ARTICLE | doi:10.20944/preprints201803.0180.v1
Subject: Materials Science, Nanotechnology Keywords: random magnetic field; safe basin; single-walled carbon nanotubes; stochastic resonance; strong nonlinearity
Online: 20 March 2018 (11:28:17 CET)
In this paper, a kind of single-walled carbon nanotube nonlinear model is developed, and the strongly nonlinear dynamic characteristics of such carbon nanotubes subjected to random magnetic field are studied. The nonlocal effect of microstructure is considered based on the theory of nonlocal elasticity. The natural frequency of the strongly nonlinear dynamic system is obtained by the energy function method, the drift coefficient and the diffusion coefficient are verified. The stationary probability density function of the system dynamic response is given and the fractal boundary of the safe basin is provided. Theoretical analysis and numerical simulation show that stochastic resonance occurs when varying the random magnetic field intensity. The boundary of safe basin has fractal characteristics and the area of safe basin decreases when the intensity of the magnetic field permeability increases.
REVIEW | doi:10.20944/preprints201608.0050.v1
Subject: Chemistry, Other Keywords: amorphous carbon; sulfur; superconductivity; peculiar magnetic behavior
Online: 5 August 2016 (07:16:18 CEST)
We report on magnetic studies of inhomogeneous commercial and synthesized amorphous carbon (a-C) and a-C doped with sulfur (a-CS) powders which exhibit (i) peculiar magnetic behavior and (ii) traces of two superconducting (SC) phase ~ Tc=33 and at 65 K. (i) The temperature dependence of zero-field-cooled (ZFC) curves measured up to room temperature show a well distinguish elusive peaks around 50-80 K, their origin is not yet known. These peaks are totally washed-out in the second ZFC sweeps and in the FC branches as well. As a result, in the vicinity of the peaks, the FC curves lie below the ZFC peaks (FC<ZFC), a phenomenon which is rarely observed. These magnetic anomalies are intrinsic properties of a-C and a-CS materials (ii) SC was observed in three different a-C sources: (a) The commercial a-C powder contains 0.21% of sulfur and it is suggested that two different a-CS phases (at 33 and 65 K) are the origin of the two SC states observed. The compositions of these two phases are not yet unknown. The small SC volume fractions of the 33 K phase can be enhanced by a solid reaction with additional sulfur at 250 ºC. (b) The synthesized a-C powder (obtained from decomposition of sucrose) is not SC. However, when mixed with sulfur and heated at 400 ºC under a protective atmosphere, the a-CS powder obtained also show traces of a SC phase at TC= 42 K. (c)The same occurs in a-C thin films. The as-grown films are not SC but a SC phase at Tc = 34 K emerges after the films were reacted with sulfur at elevated temperatures. It is concluded therefore, that all SC phases observed are due to different unknown a-CS phases. Since the a-C and a-CS powders possess SC and magnetic states, we believe that these powders resemble the high TC curates and Fe-As based systems in which the SC and the magnetic states are closed related to each other.
ARTICLE | doi:10.20944/preprints201808.0365.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: coffee; insulin resistance; metabolic syndrome X; Non-alcoholic fatty liver disease; Carbon-13 magnetic resonance spectroscopy; phytotherapy
Online: 21 August 2018 (04:38:00 CEST)
Literature is inconsistent as to how coffee affects the features of the metabolic syndrome (MetS), and which bioactive compounds are responsible for its metabolic effects. We aimed to compare the in-vivo effects of unfiltered coffee with a selected mixture of its compounds on diet-induced MetS. 24 male Sprague-Dawley rats were fed a high-fat (35% W/W) food plus 20% W/W fructose in drinking water for 14 weeks, and were randomized into three groups: control, coffee, or nutraceuticals (5-O-caffeoylquinic acid, caffeic acid, and trigonelline). Coffee or nutraceuticals were provided in drinking water in a dosage equal to 4 cups/day in a human. Compared to the controls, only coffee supplementation decreased total food intake, weight gain, and estimated average plasma glucose. Surrogate measures of insulin resistance (fasting insulin, HOMA-IR, and oral glucose tolerance) were improved at endpoint in the coffee group. Circulating triglyceride levels were also reduced by coffee. Histopathological and quantitative measurements indicated lower grades of liver steatosis after long-term coffee consumption. In conclusion, a combination of phenolic acids and trigonelline was not as effective as coffee per se in improving the components of the MetS. This points to the role of other coffee chemicals and a potential synergism between compounds.
ARTICLE | doi:10.20944/preprints201906.0264.v1
Subject: Physical Sciences, Fluids & Plasmas Keywords: laser-induced plasma; atomic spectroscopy; molecular spectroscopy; cyanide; hydrogen; carbon
Online: 26 June 2019 (07:49:09 CEST)
This work examines atomic and molecular signatures in laser-induced plasma in standard ambient temperature and pressure environments, including background contributions to the spectra that depend on the laser pulse-width. Investigations include solids, gases, and nano-particles. Abel inversions of measured line-of-sight data reveal insight into the radial plasma distribution. For nominal 6 nanosecond laser pulses and for pulse-energies in the range of 100 to 800 mJ, expansion dynamics and turbulence due to shock phenomena are elucidated to address local equilibrium details that are frequently assumed in spatially averaged emission spectroscopy. Chemical equilibrium computations reveal temperature dependence of selected plasma species. Specific interests include atomic hydrogen (H) and cyanide (CN). Atomic hydrogen spectra indicate axisymmetric shell structures and isentropic expansion of the plasma kernel over and above the usual shockwave. The recombination radiation of CN emanates within the first 100 nanoseconds for laser-induced breakdown in a 1:1 CO2:N2 gas mixture when using nanosecond laser pulses to create the micro-plasma. The micro-plasma is generated using 1064 nm, 150 mJ, 6 ns Q-switched Nd:YAG laser radiation. Measurements of the optical emission spectra utilize a 0.64 m Czerny-Turner type spectrometer and an intensified charge-coupled device.
ARTICLE | doi:10.20944/preprints201906.0095.v1
Subject: Keywords: paracetamol; laser-induced breakdown spectroscopy; cyanide; carbon Swan bands; principal component analysis; Raman spectroscopy; Fourier-Transform-infra-red spectroscopy
Online: 11 June 2019 (10:42:58 CEST)
Laser-induced breakdown spectroscopy (LIBS) of pharmaceutical drugs that contain paracetamol is investigated in air and argon atmospheres. Characteristic neutral and ionic spectral lines of various elements and molecular signatures of CN violet and C2 Swan band systems are observed. The relative hardness of all drug samples is measured as well. Principal component analysis, a multivariate method, is applied in data analysis for demarcation purposes of the drug samples. The CN violet and C2 Swan spectral radiances are investigated for evaluation of possible correlation of the chemical and molecular structures of the pharmaceuticals. Complementary Raman and Fourier-transform-infra-red spectroscopies are used record molecular spectra of the drug samples. The applicationof the above techniques for the drug screening are important for identification and mitigation of drugs that reveal additives that may cause adverse side-effects.
ARTICLE | doi:10.20944/preprints201812.0274.v1
Subject: Biology, Anatomy & Morphology Keywords: MMP-13; ADAMTS-4; FMOD; LUM; SLRPs; OA; PAMPs; DAMPs
Online: 24 December 2018 (11:27:04 CET)
Cartilage regeneration requires a balance of anabolic and catabolic processes. This study examined the susceptibility of fibromodulin (FMOD) and lumican (LUM) to degradation by MMP-13, ADAMTS-4 and ADAMTS-5, the three major degradative proteinases in articular cartilage in osteoarthritis (OA). Immunolocalisation of FMOD and LUM in foot sections of developmental cartilages demonstrated prominent localisations in metatarsal and phalangeal foetal rudiment cartilages and growth plate. An MMP-13 neoepitope antibody (TsYG11) demonstrated localisation of MMP-13 cleaved FMOD in the hypertrophic chondrocytes of the metatarsal growth plate. FMOD was more prominently localised in the superficial cartilage of normal and fibrillated zones in OA cartilage, TsYG11 positive FMOD was located deeper in the cartilage samples. Ab TsYG11 also identified FMOD fragmentation in Western blots of extracts of normal and fibrillated cartilage and total knee replacement OA cartilage. The C-terminal anti-FMOD used in this study (PR-184) failed to identify FMOD fragmentation due to C terminal processing, an equivalent Ab to the C-terminus of LUM (pAb PR-353) identified 3 prominent LUM fragments in OA human knee cartilages. In-vitro digestion of human knee cartilage with MMP-13, ADAMTS-4 and ADAMTS-5 generated equivalently sized FMOD fragments of 54, 45 and 32kDa to those in blots of OA cartilage, LUM was not less susceptible to fragmention in in-vitro digestions however Ab PR-353 detected N-terminally processed LUM fragments of 39, 38 and 22 kDa in 65-80 year old OA knee cartilage. FMOD and LUM were differentially processed during in-vitro digestions with MMP-13, ADAMTS-4 and ADAMTS-5 with FMOD susceptible to degradation by MMP-13, ADAMTS-4 and to a lesser extent ADAMTS-5 however LUM was less susceptible to fragmentation. FMOD was processed by MMP-13 in metatarsal and phalangeal foetal rudiment developmental cartilages and growth plate indicating a role in skeletogenesis.
ARTICLE | doi:10.20944/preprints201810.0574.v1
Subject: Materials Science, Nanotechnology Keywords: carmustine-loaded micelle; brain targeting; borneol; IL-13 receptor; BBB
Online: 24 October 2018 (11:53:00 CEST)
Abstract: Tumor-targeting and blood-brain barrier (BBB)-penetrating are highly desirable for the treatment of glioma. In this study, we developed Pep-1&borneol-bifunctionalized carmustin-loaded micelles (Pep-1/Bor/CMS-M) capable of targeting to IL-13 receptor-overexpressed glioma and penetrating the brain microvascular endothelial cells-associated physiologic barriers. Pep-1/Bor/CMS-M were nearly spherical particles with a dimeter of 32.6 ± 1.1 nm and zeta potential of -21.3 ± 3.1 mV. Carmustine (CMS) released from Pep-1/Bor/CMS-M in pH 7.4 was significantly faster than in acidic environments. In human glioma BT325 cellular studies, Pep-1/Bor/CMS-M remarkably increased the cytotoxicity, notably improved the internalization and effectively induced the cell apoptosis. Likewise, in human brain microvascular endothelial cells (HBMEC) cells, Pep-1/Bor/CMS-M obviously promoted the cellular uptake, rapidly decreased the transepithelial electrical resistance (TEER) and thereby of enhancing the ability of penetration. In orthotopic Luc-BT325 glioma tumor-bearing nude mouse models, the stronger fluorescence signal and longer retention were observed in brain tissues compared with other controls, after single administration of DiD-labelled Pep-1/Bor/M (DiD/Pep-1/Bor/M). Importantly, Pep-1/Bor/CMS-M displayed the strongest inhibition of tumor growth, the longest survival period and low systemic toxicity in treating orthotopic glioma tumor-bearing nude mice. Simultaneous functionalization of Pep-1 and borneol offers a novel strategy for designing CMS-based nanomedicine and precisely treating glioma.
ARTICLE | doi:10.20944/preprints202201.0037.v1
Subject: Life Sciences, Microbiology Keywords: Antimicrobial nanomaterials; Carbon Nanotubes; Graphene; Magnetic Nanoparticles; hydrogel; Photodynamic Therapy; Photothermal Therapy; Nanocarrier
Online: 5 January 2022 (12:02:34 CET)
Microbial diseases have been declared one of the main threats to humanity, which is why, in recent years, great interest has been generated in the development of nanocomposites with antimicrobial capacity. In the present work, two magnetic nanocomposites, based on Graphene Oxide (GO) and Multiwall Carbon Nanotubes (MWCNTs) were studied. The synthesis of these magnetic nanocomposites consisted of three phases: first, the synthesis of Iron Magnetic Nanoparticles (MNPs) was carried out in the presence of MWCNTs and GO using the Co-precipitation method. The second phase consisted of the adsorption of photosensitizer menthol-Zinc phthalocyanine (ZnMintPc) into MWCNTs and GO, and the third phase was the encapsulation in poly (N-vinylcaprolactam-co-poly(ethylene glycol diacrylate)) poly (VCL-co-PEGDA) polymer VCL/PEGDA a biocompatible hydrogel, in order to obtain the magnetic nanocomposites: VCL/PEGDA-MNPs-MWCNTs-ZnMintPc and VCL/PEGDA-MNPs-GO-ZnMintPc. In vitro studies were carried out using Escherichia coli and Staphylococcus aureus bacteria and the Candida albicans yeast based on the PTT/PDT effect. This research describes the optical, morphological, magnetic and photophysical characterizations of nanocomposites and their application as antimicrobial agents. It was evaluated the antimicrobial effect of magnetics nanocomposites based on the Photodynamic/Photothermal (PDT/PTT) effect; for this purpose, doses of 65 mW cm-2 at 630 nm of light were used. The VCL/PEGDA-MNPs-GO-ZnMintPc nanocomposite was able to eliminate colonies of E. coli and S. aureus, while VCL/PEGDA-MNPs-MWCNTs-ZnMintPc nanocomposite was able to eliminate the three types of microorganisms; consequently, the latter is considered a broad-spectrum of antimicrobial agent in PDT and PTT.
ARTICLE | doi:10.20944/preprints202111.0498.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: bortezomib; IL-13; IL-1Ra; IL-4; multiple myeloma; OS; PFS
Online: 26 November 2021 (10:31:50 CET)
Multiple myeloma (MM) is characterized by the malignant proliferation of monoclonal plasma cells in the bone marrow with an elevation in monoclonal paraprotein, renal impairment, hypercalcemia, lytic bony lesions, and anemia. Immune cells and associated cytokines play a significant role in MM growth, progression, and dissemination. While some cytokines and their clinical significance are well described in MM biology, others remain relatively unknown. The aim of the present study was to assess the impact of pretreatment serum levels of 27 selected cytokines on progression-free survival (PFS) and overall survival (OS) in MM patients before first-line therapy with bortezomib-based regimens. Serum cytokine levels were assayed with a Bio-Rad Bio-Plex Pro Human Cytokine 27-Plex Assay on the MAGPIX Multiplex Reader and the Bio-Plex® 200 System (Bio-Rad) including IL-1β, IL-1Ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-17, Eotaxin, FGF, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α, and VEGF. A total of 61 MM patients were examined. Most patients received a bortezomib, cyclophosphamide and dexamethasone (VCD) chemotherapy regimen. In the final multivariate model, IL-13 cytokine level (HR 0.1411, 95% CI: 0.0240-0.8291, p = 0.0302), and ASCT (HR 0.3722, 95% CI: 0.1826-0.7585, p=0.0065) significantly impacted PFS. Furthermore, ASCT (HR 0.142, 95% CI: 0.046-0.438, p=0.0007), presence of bone disease at diagnosis (HR 3.826, 95% CI: 1.471-9.949, p=0.0059) and two cytokine levels- IL-1Ra (HR 1.017, 95% CI: 1.004-1.030, p= 0.0091) and IL-4 (HR 0.161, 95% CI: 0.037-0.698, p = 0.0147) were independent predictors of OS. Three clusters of MM patients were identified with different cytokine profiles. In conclusion, serum pretreatment levels of IL-13 and IL-4 are predictors of better PFS and OS, respectively, whereas IL-1Ra pretreatment levels negatively impact OS in MM patients treated with bortezomib-based chemotherapy. Cytokine signature profile may have a potential influence on the outcome of patients treated with bortezomib.
ARTICLE | doi:10.20944/preprints201911.0183.v2
Subject: Arts & Humanities, Architecture And Design Keywords: informal settlement; sustainable neighborhood; approaches; district 13 of Kabul city Afghanistan
Online: 20 November 2019 (11:20:52 CET)
Abstract: Afghanistan witnessed rapid urbanization in recent decades due to the post-war recovery process. When the war ended in 2001 by fall of Taliban regime, most Afghans refugees returned to urban areas of Afghanistan, especially in Kabul city. Moreover, the rapid urbanization, migration from rural areas, and population growth impacted on Kabul city with the manifestation of informal settlement. The residents of informal settlements suffer social and economic exclusion from the benefit and opportunity of an urban environment. Furthermore, the residents of informal settlements experience disadvantages by geographical marginalization, shortage of basic infrastructure, improper governance framework, vulnerability into the effect of poor environment, and natural disasters. With all the above, the problems of informal settlements are considered enormous challenges for informal residents. Therefore, this paper aims to identify the proper approaches to addressing informal settlement problems in District 13 of Kabul city. To reach the aim of the research, the interview and questionnaires survey used as an instrument in data collection. Consequently, the finding of this paper indicates that through the resident’s preferences, government capacity, and District 13 physical condition there are three approaches which can be implemented and adopted for improvement of informal settlement in District 13 of Kabul city, which is settlement upgrading as the first option, the land readjustment as the second option and urban redevelopment as the last option.
REVIEW | doi:10.20944/preprints202108.0496.v1
Subject: Life Sciences, Other Keywords: carbon farming; carbon foot printing; low carbon agriculture; carbon sequestration; carbon economy
Online: 25 August 2021 (15:01:05 CEST)
Carbon farming is a capable strategy for more sustainable production of food and other related products. It seeks to produce the diverse array of natural farming methods and marketable products simultaneously. In agroforestry system, carbon sequestration is done by incorporating carbon dioxide (CO2) into plant biomass via photosynthesis. Carbon is, thus, stored in reserves of above-ground biomass, such as timber or branches, and below-ground biomass such as roots, or organic carbon in the soil. In addition to the significance of carbon sequestration in climate change mitigation, soil organic carbon (SOC) is an imperative indicator for the soil health as well as fertility. The change in SOC can explain whether the land use pattern degrades or improves the soil fertility. SOC, found in the soil in the form of soil organic matter (SOM), helps to improve soil health either directly or indirectly. Its direct consequence is related to the process of mineralization. Further, agroforestry is highly capable of generating huge amounts of bio-mass. In fact, agroforestry is believed to be particularly suitable for replenishment of SOC. Therefore, efforts should be made to convince farmers for their resource-use efficiency and soil conserving ability in order to get maximum benefits out of agriculture. According to food and agriculture organization (FAO,) agriculture, forestry, and other land use practices account for 24% of global greenhouse gas (GHG) emissions, and total global livestock emissions of 7.1 gigatons of CO2-equivalent per year, representing 14.5% of total anthropogenic GHG emissions. Agroforestry system that deliberately integrates trees and crops with livestock in the agricultural production could potentially increase carbon sequestration and decrease GHG emission from the terrestrial ecosystems, thus, helping in global climatic change mitigation. This study, therefore, aimed at clarification about carbon farming, modifications in carbon cycle and carbon sequestration during agricultural development in addition to benefits of agroforestry.
ARTICLE | doi:10.20944/preprints202105.0258.v1
Subject: Life Sciences, Biochemistry Keywords: ANGPTL3-DOCK7; irisin; c-peptide; triglyceride; interleukin 13; lipid metabolism; insulin resistance; Arab population
Online: 12 May 2021 (07:28:31 CEST)
ANGPTL3 is an important regulator of lipid metabolism. Its inhibition in people with hypercholesteremia reduces plasma lipid levels dramatically. Genome-wide association studies have associated ANGPTL3 variants with lipid traits. Irisin, an exercise modulated protein, has been associated with lipid metabolism. Intracellular accumulation of lipids impairs insulin action and contributes to metabolic disorders. In this study, we evaluate the impact of ANGPTL3 variants on levels of irisin and markers associated with lipid metabolism and insulin resistance. ANGPTL3 rs1748197 and rs12130333 variants were genotyped in a cohort of 278 Arab individuals from Kuwait. Levels of irisin and other metabolic markers were measured by ELISA. Significance of association signals was assessed using Bonferroni-corrected P-values and empirical P-values. The study variants were significantly associated with low levels of c-peptide and irisin. Levels of c-peptide and irisin were mediated by interaction between carrier genotypes (GA+AA) at rs1748197 and measures of IL13 and TG, respectively. While levels of c-peptide and IL13 were directly correlated in individuals with reference genotype, they were inversely correlated in individuals with carrier genotype. Irisin correlated positively with TG which is strong in individuals with carrier genotypes. These observations illustrate ANGPTL3 as a potential link connecting lipid metabolism, insulin resistance and cardioprotection.
ARTICLE | doi:10.20944/preprints201607.0085.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: CNN; Deep Learning; AlexNet; VGGNet; Texture Descriptor; Garment Categories; 13 Garment Trend Identification; Design Classification for Garments.
Online: 27 July 2016 (15:39:53 CEST)
Automatic garments design class identification for recommending the fashion trends is important nowadays because of the rapid growth of online shopping. By learning the properties of images efficiently, a machine can give better accuracy of classification. Several methods, based on Hand-Engineered feature coding exist for identifying garments design classes. But, most of the time, those methods do not help to achieve better results. Recently, Deep Convolutional Neural Networks (CNNs) have shown better performances for different object recognition. Deep CNN uses multiple levels of representation and abstraction that helps a machine to understand the types of data (images, sound, and text) more accurately. In this paper, we have applied deep CNN for identifying garments design classes. To evaluate the performances, we used two well-known CNN models AlexNet and VGGNet on two different datasets. We also propose a new CNN model based on AlexNet and found better results than existing state-of-the-art by a significant margin.
ARTICLE | doi:10.20944/preprints202211.0479.v1
Subject: Earth Sciences, Environmental Sciences Keywords: wildfires; carbon cycle; forestry carbon emissions
Online: 25 November 2022 (10:13:04 CET)
Forest plantations can substantially contribute to carbon sequestration and greenhouse gases (GHG) mitigation at the country and global scale. Forest fires (specially when combined with droughts) may significantly reduce such carbon sequestration capability. IPCC has global scale estimates for such losses, but they can vary widely depending on crops, climate, topography and management, among others. IPCC defines a factor for biomass loss as a consequence of forest fires, expressed as a fraction of total biomass. This methodology implies using aggregated data and the default emission factor, being only recommended for countries where wildfires are not a key category. In Chile, and over the last decade, there are between 5,000 to 8,000 wildfires annually (average 6,398 for the period 2011-2020), burning an average of 122,328 hectares each year. Countries may progress in the refinement of such factors depending on the availability and reliability of local values. This paper aims at estimating C_f values for the main forest plantation species in Chile: Pinus radiata, Eucalyptus nitens, and Eucalyptus globulus, across different age-classes and forest fire severities. To this aim we assessed the biomass loss after forest fires for a stratified sample of forest plots for the season 2018-2019. We fitted a model to predict the amount of biomass loss during fires, and in this way, predict the emissions associated to wildfires. The model employs very simple predictive variables, age and species, because statistics for burnt areas in plantations are only provided by age-classes and species, without details about productivity or management.
REVIEW | doi:10.20944/preprints202009.0670.v1
Subject: Earth Sciences, Atmospheric Science Keywords: petroleum refining carbon footprints; refining carbon footprints; refined product carbon footprints
Online: 27 September 2020 (08:32:10 CEST)
Energy-related greenhouse gas emissions dominate the carbon footprints of most product systems, and petroleum is one of the main types of energy sources. This is consumed as a variety of refined products – most notably diesel, petrol (gasoline) and jet fuel (kerosene). Refined product carbon footprints are of great importance to regulators, policymakers and environmental decision-makers. For instance, they are at the heart of legislation such as the European Union’s Renewable Energy Directive or the United States’ Renewable Fuels Standard. This study identified 14 datasets that report footprints for the same system, European petroleum refining. For the main refined products – diesel, petrol and jet fuel – footprints vary by at least a factor of three. For minor products, the variation is even greater. Five different organs of the European Commission have estimated refining footprints: for main products these are relatively harmonic; for minor products much less so. The footprint variation is due mainly to differing approaches to refinery modelling, especially regarding the rationale and methods applied to assign shares of the total burden from the petroleum refinery operation to the individual products. Given the economic/social importance of refined products, a better harmony of their footprints would be valuable to their users.
ARTICLE | doi:10.20944/preprints202007.0576.v4
Subject: Earth Sciences, Atmospheric Science Keywords: carbon dioxide; global warming; sequestration; carbon cycle; biomass sequestration, carbon sequestration, CO2
Online: 15 January 2021 (12:34:52 CET)
Many corporations aspire to become Net Zero Carbon Dioxide by 2030-2050. This paper examines what it will take. It requires understanding where energy is produced and consumed, the magnitude of CO2 generation, and the Carbon Cycle. Reviews are provided for prior technologies for reducing CO2 emissions from fossil to focus on their limitations and to show that none offer a complete solution. Both biofuels and CO2 sequestration reduce future CO2 emissions from fossil fuels. They will not remove CO2 already in the atmosphere. Planting trees has been proposed as one solution. Trees are a temporary solution. When they die, they decompose and release their carbon as CO2 to the atmosphere. The only way to permanently remove CO2 already in the atmosphere is to break the Carbon Cycle by growing biomass from atmospheric CO2 and sequestering biomass carbon. Permanent sequestration of leaves is proposed as a solution. Leaves have a short Carbon Cycle time constant. They renew and decompose every year. Theoretically, sequestrating a fraction of the world’s tree leaves can get the world to Net Zero without disturbing the underlying forests. This would be CO2 capture in its simplest and most natural form. Permanent sequestration may be achieved by redesigning landfills to discourage decomposition. In traditional landfills, waste undergoes several stages of decomposition, including rapid initial aerobic decomposition to CO2, followed by slow anaerobic decomposition to methane and CO2. The latter can take hundreds to thousands of years. Understanding landfill chemistry provides clues to disrupting decomposition at each phase.
OPINION | doi:10.3390/sci2030057
Subject: Keywords: blue carbon; carbon; carbon stock; carbon sequestration; climate change; CO<sub>2</sub> emissions; mangrove; mitigation
Online: 23 July 2020 (00:00:00 CEST)
Mangrove forests store and sequester large area-specific quantities of blue carbon (Corg). Except for tundra and peatlands, mangroves store more Corg per unit area than any other ecosystem. Mean mangrove Corg stock is 738.9 Mg Corg ha−1 and mean global stock is 6.17 Pg Corg, which equates to only 0.4–7% of terrestrial ecosystem Corg stocks but 17% of total tropical marine Corg stocks. Seagrasses sequester more Corg per unit area than mangroves (179.6 g Corg m−2·a−1) but twice the Corg sequestered by mangroves globally (15 Tg Corg a−1). Mangroves sequester only 4% (range 1.3–8%) of Corg sequestered by terrestrial ecosystems, indicating that mangroves are a minor contributor to global C storage and sequestration. CO2 emissions from mangrove losses equate to 0.036 Pg CO2-equivalents a−1 based on rates of C sequestration but 0.088 Pg CO2-equivalents a−1 based on complete destruction for conversion to aquaculture and agriculture. Mangrove CO2 emissions account for only 0.2% of total global CO2 emissions but 18% of CO2 emissions from the tropical coastal ocean. Despite significant data limitations, the role of mangrove ecosystems in climate change mitigation is globally insignificant but may be more significant and effective at the national and regional scale.
REVIEW | doi:10.20944/preprints202008.0187.v1
Subject: Engineering, Civil Engineering Keywords: Sequestration, Carbon Dioxide, concrete strength, carbon footprint.
Online: 7 August 2020 (11:21:18 CEST)
Carbon dioxide, CO2 accounts for most of the emission from all the types of greenhouse gasses in the world. The ability of CO2 to remain longer than other greenhouse gases and the convenience of producing CO2 has resulted in its high projection in a yearly manner. The prime factor for the emission of CO2 are from the actions of human beings. One such human act is the concrete industry. Total emissions from the concrete industry could therefore contribute as much as 8% of global CO2 emissions. Sequestered CO2 in concrete can provide an impact on reducing the carbon footprint and is also able to improve the compressive strength of concrete. During this process, the sequestered carbon dioxide chemically reacts with cement to produce a mineral, trapping carbon dioxide gas in the concrete. Hence, sequestering carbon dioxide gas in concrete does not only on a bigger scale reduces carbon footprint, but it also reduces the impact the construction industry has on the environment. This paper presents a detailed review on the chemical reaction that takes place during the sequestration of carbon dioxide and the research published on the effects of carbon dioxide sequestered concrete on its properties. The impact this process has on the concrete industry and the environment is discussed in this paper.
ARTICLE | doi:10.20944/preprints202007.0288.v1
Online: 14 July 2020 (03:53:45 CEST)
The questions on who is entitled to benefit from REDD+ transactions remains one of the most controversially debated issues around cooperative efforts to reduce deforestation in developing countries. REDD+ has been conceived as international framework for voluntary efforts of developing countries to reduce greenhouse gas emissions and enhance carbon removals from forest activities. Designed as international framework under the UNFCCC that calculates emission reductions and removals (ERRs) at the national -and as an interim step on the subnational level – REDD+ is primarily a creature of international law. However, in defining forest-carbon ERRs the international framework competes with national emission trading systems and domestic REDD+ legislation as well as private standards that define units traded on the voluntary carbon market. The definition of various carbon units is closely linked to the question on who is entitled to participate in REDD+ and benefit from the sale of ERRs under results-based payment schemes or carbon market transactions. This paper applies a legal lens to the various claims to participate in REDD+ transactions. It tries to disentangle the various rights to ERRs, various carbon credits, and payments that come with REDD+ and that almost always create confusion and not seldom conflict around REDD+ implementation. The definition of carbon rights and the legal nature of carbon credits depends on local law and differs between countries. However, there are a number of legal considerations that apply and certain underlying concepts are relevant for the understanding of REDD+ transactions and the allocation of benefits and burdens of conservation activities.
ARTICLE | doi:10.20944/preprints201810.0716.v1
Subject: Earth Sciences, Environmental Sciences Keywords: carbon; energy; campus; sustainability; city; low carbon
Online: 30 October 2018 (08:53:17 CET)
The establishment of low carbon assessment initiatives is a crucial task especially at the city level. The determination of which source of carbon contributed more require robust data set and strategic approach. Hence, by using the campus as a small city approach, the establishment of carbon assessment and its’ reduction initiatives was required to keep track of the hotspot of the carbon source. The substantial amount of carbon source from campus operations such as energy consumption in the building, waste generation, and water consumption were identified. Moreover, as institutions of higher education, the execution of low carbon campus was initiated structurally involves the triangulation of research activities, teaching & learning and as well as campus operations or known as campus living lab approach. The application of low carbon cities framework, LCCF and assessment system enables to strategize the low carbon campus initiatives through the use of carbon footprint concept and the LCCF carbon track.
ARTICLE | doi:10.20944/preprints202007.0525.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Ice Complex; Yedoma; organic carbon; inorganic carbon; total carbon; Batagay megaslump; North Yakutia
Online: 22 July 2020 (11:28:37 CEST)
The most massive and fast-eroding thaw slump of the Northern Hemisphere located in the Yana uplands of northern Yakutia was investigated to assess in detail the cryogenic inventory and carbon pools of two distinctive Ice Complex stratigraphic units and the uppermost cover deposits. Differentiating into modern and Holocene near-surface layers (active layer and shielding layer), highest total carbon contents were found in the active layer (18.7 kg m-2), while the shielding layer yielded much lower carbon content of 1.8 kg m-2. The late Pleistocene upper Ice Complex contained 10.4 kg m-2 total carbon, and the mid-Pleistocene lower Ice Complex 17.7 kg m-2. The proportion of organic carbon from total carbon content is well above 70% in all studied units with 94 % in the active layer, 73% in the shielding layer, 83% in the upper Ice Complex and 79% in the lower Ice Complex. Inorganic carbon is low in the overall structure of the deposits.
ARTICLE | doi:10.20944/preprints202205.0361.v1
Subject: Engineering, Energy & Fuel Technology Keywords: grills; carbon footprints; carbon intensities; full fuel cycle
Online: 26 May 2022 (10:27:15 CEST)
Grill-specific footprints for common fuels/grill types in the USA are estimated from public information and data from a major grill manufacturer. These are a function of both 1) a fuel’s footprint and 2) a grill’s efficiency of cooking. In 2022, grill-specific footprints vary by 9:1. A typical gas grill is highest at 3.6 lb CO2e/grill session, nine times that of a wood-pellet grill, lowest at 0.4 lb. Charcoal briquettes, electricity and super-efficient gas grills come in-between. Pellets are lowest, because they are made from waste wood and their production burden is modest. Electricity has the highest fuel footprint, yet the second-lowest grill-specific footprint, thanks to its high efficiency. Briquettes come in fourth, because their production involves fossil gas, and they contain some fossil coal. Grill efficiency is key for gas (natural gas or propane): a typical gas grill has twice the footprint of a super-efficient one. In 2027, with bio substitution, the super-efficient gas grill would move ahead of pellets. Electricity and charcoal could improve but would still place fifth and sixth. The range of grill-specific footprints could fall to 4.5:1, within a much-lower range, the highest footprint in 2027 almost 60% lower than 2022’s highest.
ARTICLE | doi:10.20944/preprints202204.0066.v2
Subject: Engineering, Energy & Fuel Technology Keywords: greenhouse; biomass; carbon dioxide; capture carbon dioxide; gasification
Online: 16 May 2022 (04:50:47 CEST)
The gasification of sugarcane cutting residues (RAC) is a process that occurs in a gasifier where the transformation of this raw material into a solid-state and a gasifying agent with a moderate calorific value occurs, thanks to the application of heat. And under restricted oxygen levels, we can say that there are several styles of gasifiers for air, steam, oxygen, and hydrogen, all of which have a performance that can be analyzed and categorized by their performance to avoid damage to the environment. (1) The objective of this article is based on the mathematical development using simulation of the gasification of cane cutting residues. (2) In the methodology, the simulation of the gasification and CO2 capture process was developed from the biomass residues of the sugarcane cutting residues; it was carried out as a transformation of the primary fuel into a gas stream whose main components are CO2 and H2, which can be separated relatively easily by their concentrations, available pressures and in some cases, their temperatures; (3) According to the kinetic data obtained, the second-order reaction in the transformation and improvement of the process was identified; applying to the optimization of development in the capture of CO2, contributing to the reduction of greenhouse gases. (4) The gasification simulation process results in a biomass conversion corresponding to 93% of its feed and the formation of volatiles whose molar fraction corresponds to 37% H2, 12% CH4, 37% CO and 12 % CO2.
REVIEW | doi:10.20944/preprints202103.0029.v1
Subject: Earth Sciences, Atmospheric Science Keywords: miombo; carbon stocks; aboveground; belowground; soil organic carbon
Online: 1 March 2021 (14:16:54 CET)
Miombo woodlands are extensive dry forest ecosystems in central and southern Africa covering ≈2.7 million km2. Despite their vast expanse and global importance for carbon storage, the long-term carbon stocks and dynamics have been poorly researched. The objective of this paper is to present and summarize the evidence gathered on above- and belowground (root and soil) carbon stocks of miombo woodlands from the 1960s to mid-2018 through a review. We analyzed data to answer: (1) What is the range of aboveground and belowground carbon stocks found in miombo woodlands over the last six decades? (2) Are there differences in carbon stocks based on land-management categories? (3) Does precipitation influence aboveground carbon stocks in old-growth miombo? (4) Do differences in cover type, age and region influence carbon stocks? (5) How does previous land-use affect carbon stocks in re-growth miombo? A literature review protocol was used to identify 56 publications from which quantitative data on aboveground and soil carbon pools were extracted. We found that the mean aboveground carbon stock in old-growth miombo was 30.83±16.76 Mg C ha-1 (range 1.48—107.24 Mg ha-1). Old-growth miombo had an average calculated root carbon stock of 16.49±9.18 Mg C ha-1 (range 0.8—57.81 Mg ha-1). Soil carbon stocks in old-growth miombo varied widely, between 8.75 and 134.6 Mg C ha-1 while in re-growth miombo they varied between 10.73 and 52.2 Mg C ha-1. It must be noted these soil data are given only for information; they inconsistently refer to varying soil depths and are thus difficult to interpret. The wide range reported suggests a need for further studies, much more systematic in methods and reporting. Other limitations of the dataset include the lack of systematic sampling and lack of data in some countries, viz. Angola and Democratic Republic of the Congo.
ARTICLE | doi:10.20944/preprints202002.0317.v1
Subject: Earth Sciences, Atmospheric Science Keywords: carbon dioxide emissions; carbon dioxide concentrations; Atmospheric Fraction
Online: 23 February 2020 (10:48:35 CET)
In this work, a semi-empirical relationship of carbon dioxide emissions with atmospheric CO2 concentrations has been developed that is capable of closely replicating observations from 1751 to 2018. The correlation consists of a superposition of a linear component that may be attributed to the net emission flux from land use changes coupled with a rapidly varying component of the terrestrial sink combined with a fossil-fuel combustion/cement production emissions-based calculation with a single, fixed, scaling parameter determined by the ocean sink coupled with the remaining slowly varying component of the land sink (the fossil-fuel combustion airborne fraction).
ARTICLE | doi:10.20944/preprints201810.0588.v1
Subject: Earth Sciences, Environmental Sciences Keywords: carbon; energy; campus; sustainability; city; low carbon campus
Online: 25 October 2018 (05:15:25 CEST)
The establishment of low carbon assessment initiatives is a crucial task especially at the city level. The determination of which source of carbon contributed more require robust data set and strategic approach. Hence, by using the campus as a small city approach, the establishment of carbon assessment and its’ reduction initiatives was required to keep track of the hotspot of the carbon source. The substantial amount of carbon source from campus operations such as energy consumption in the building, waste generation, and water consumption were identified. Moreover, as institutions of higher education, the execution of low carbon campus was initiated structurally involves the triangulation of research activities, teaching & learning and as well as campus operations or known as campus living lab approach. The application of low carbon cities framework, LCCF and assessment system enables to strategize the low carbon campus initiatives through the use of carbon footprint concept and the LCCF carbon track.
ARTICLE | doi:10.20944/preprints201807.0249.v1
Subject: Engineering, Mechanical Engineering Keywords: carbon concrete composites; low-cost carbon fibers; pultrusion
Online: 13 July 2018 (17:51:12 CEST)
Carbon concrete PAN/lignin-based CF composites are a new promising material class for the building industry. The replacement of the traditional heavy and corroding steel reinforcement by carbon fiber (CF) based reinforcements offers many significant advantages: a higher protection of environmental resources because of lower CO2 consumption during cement production, a longer lifecycle and thus muss less damage in structural components and a higher degree of design freedom because lightweight solutions can be realized. However, due to cost pressure in civil engineering, completely new process chains are required to manufacture CF based reinforcement structures for concrete. The article describes the necessary process steps in order to develop CF reinforcement: (1) the production of cost-effective CF using novel carbon fiber lines, (2) the fabrication of CF rebars with different geometry profiles. It was found that PAN/lignin-based CF is currently the most promising material in order to meet the future market demands. However, significant research needs to be undertaken in order to improve the properties of lignin-based and PAN/lignin-based CF, respectively. The CF can be manufactured to CF-based rebars using different manufacturing technologies which have been developed on prototype level in this study.
ARTICLE | doi:10.20944/preprints202011.0200.v1
Subject: Engineering, Automotive Engineering Keywords: artificial neural network; APS; cavitation erosion; ceramic coatings; multi-objectives optimization; wear; hardness; microstructure; alumina – titania; Al2O3-13%TiO2.
Online: 4 November 2020 (16:01:50 CET)
The study aims to elaborate a neural model and algorithm for optimising hardness and porosity of coatings and thus ensure that they have superior cavitation erosion resistance. Al2O3-13wt.%TiO2 ceramic coatings were deposited onto 316L stainless steel by atmospheric plasma spray (ASP). The coatings were prepared with different values of two spray process parameters: the stand-off distance and torch velocity. Microstructure, porosity and microhardness of the coatings were examined. Cavitation erosion tests were conducted in compliance with the ASTM G32 standard. Artificial neural networks (ANN) were employed to elaborate the model, and the multi-objectives genetic algorithm (MOGA) was used to optimise both properties and cavitation erosion resistance of the coatings. Results were analysed with Matlab software by Neural Network Toolbox and Global Optimization Toolbox. The fusion of artificial intelligence methods (ANN+MOGA) is essential for future selection of thermal spray process parameters, especially for the design of ceramic coatings with specified functional properties. Selection of these parameters is a multicriteria decision problem. The proposed method made it possible to find a Pareto front, i.e. trade-offs between several conflicting objectives – maximising the hardness and cavitation erosion resistance of Al2O3-13%TiO2 coatings and, at the same time, minimizing their porosity.
ARTICLE | doi:10.20944/preprints202010.0566.v1
Subject: Earth Sciences, Environmental Sciences Keywords: inorganic carbon; organic carbon and nitrogen; carbon and nitrogen isotopes; coastal sediments; environmental significance
Online: 27 October 2020 (21:41:21 CET)
Carbon and nitrogen contents and their isotopic components and AMS radiocarbon dating ages were measured for 57 coastal sediments from Weizhou Island to analyze the distribution of total inorganic carbon (TIC) and its carbon and oxygen isotopic components (δ13Ccarb and δ18Ocarb), total organic carbon (TOC) and total nitrogen (TN) contents and their stable isotopic components (δ13CTOC and δ15NTN) and environmental significance. The results showed that the oldest age of coastal sediments on Weizhou Island was 2750 cal. a BP, and the average TIC contents of A1, A2, B1, C1, and D1 in the intertidal zone were all greater than 5%, where δ13Ccarb and δ18Ocarb were enriched, while the TIC contents in A3, C2, and D2 of the supra-tidal zone were low, where δ13Ccarb and δ18Ocarb were depleted. Moreover, TIC decreased sharply from the estuary to upstream region in the C1-C2 section. The average C/N ratio was 7.02, and δ13CTOC and δ15NTN were between -14.96‰~-27.26‰ and -14.38‰~4.12‰, respectively. These measurements indicated that the TIC in coastal sediments mainly came from seawater. A1, A2, and B1 in the northern intertidal zone exhibited organic terrestrial signals because of C3 and C4 plant inputs, which proved that the important source of the northern coast of Weizhou Island came from the island. The lacustrine facies deposits were mainly distributed in the upper reaches of the river, the northern coastline was rapidly advancing toward the sea, and part of the southwestern coastal sediments rapidly accumulated to the shore under the influence of a storm surge. The relative sea level of the Weizhou Island area has continuously declined at a rate of approximately 2.07 mm/a, using beach rock as a marker, since the Holocene.
ARTICLE | doi:10.20944/preprints202111.0296.v1
Subject: Engineering, General Engineering Keywords: decarbonisation; carbon footprint; net-zero; resources; energy consumption; implementation; manufacturing; product carbon footprint; carbon neutrality
Online: 17 November 2021 (10:12:59 CET)
From the perspective of manufacturing companies, the political, media and economic discourse on decarbonisation of the recent years manifests itself as an increasing social expectation of action. In Germany in particular, this discourse is also being driven forward by powerful companies, respectively sectors, most notably the automotive industry. Against this background, it was examined how German manufacturing companies react to rising societal pressure and emerging policies. It is examined which measures the companies have taken or plan to take to reduce their footprint, which aspirations are associated with this and by which structural characteristics (company size, energy intensity, sector) these are influenced. A mix methods approach was applied, utilising data gathered from approx. 900 companies in context of the Energy Efficiency Index of German Industry (EEI), along with media research focusing on decarbonisation plans and initiatives announced. We demonstrate that one-size-serves-all approaches are not suitable to decarbonise industry as the situation and ambitions differ considerably depending on size, energy intensity and sector. Even though the level of ambition and urgency is high, particularly micro and energy intensive companies are challenged. The research uncovers a series of questions that call for attention to materialise the ambitions and address the challenges outlined.
ARTICLE | doi:10.20944/preprints202203.0330.v2
Subject: Biology, Forestry Keywords: capital return rate; expected value; carbon storage; carbon rent
Online: 26 April 2022 (09:45:34 CEST)
The effect of capitalization premium in forest estate markets on forest management and climate change mitigation economics is investigated. It is shown that proportional goodwill in capitalization induces linear scaling of the financial return, without any contribution to sound management practices. However, there is a financial discontinuity as harvesting deteriorates goodwill. On the contrary, capitalization premium set on bare land as a tangible asset would increase timber storage and carbon sequestration. Observations indicate that the proportional goodwill is closer to reality within the Nordic Region, resulting in continuity problems but a reduced capital expense for carbon storage.
Subject: Earth Sciences, Atmospheric Science Keywords: carbon sequestration; biochar; soil carbon; basalt; enhanced weathering; agriculture
Online: 3 March 2021 (09:45:11 CET)
One of society’s greatest challenges is sequestering vast amounts of carbon to avoid dangerous climate change without driving competition for land and resources. Here we assess the potential of an integrated approach based on enhancement of natural biogeochemical cycles in agro-ecosystems that stimulate carbon capture and storage while increasing resilience and long-term productivity. The method integrates plant photosynthesis in the form of (cover) crops and agroforestry which drives carbon capture. Belowground plant-carbon is efficiently stored as stable soil organic carbon (SOC). Aboveground crop and tree residues are pyrolyzed into biochar, which is applied to the soil reducing carbon release through decomposition. Enhanced weathering of basalt powder worked into the soil further captures and stores carbon, while releasing nutrients and alkalinity. The integrated system is regenerative, through enhanced virtuous cycles that lead to improved plant capture, biomass storage and crop yield, the prerequisites for large-scale carbon sequestration along with food security.
REVIEW | doi:10.20944/preprints202009.0298.v1
Subject: Materials Science, Nanotechnology Keywords: Nanomaterials; Carbon nanotubes; Rice husk; Agriculture waste; Carbon nanofibres
Online: 13 September 2020 (16:23:49 CEST)
Today is the era of nanoscience and nanotechnology, which finds applications in the field of medicine, electronics, or environmental cleanup. Even though the nanotechnology is in its emerging phase, but still it provides solutions to numerous challenges. Nanotechnology and nanoparticles are found very effective because of their unique chemical and physical properties, high surface area, but their high cost is one of the major hurdles in its wider application. So, the synthesis of nanomaterials especially 2D nanomaterials from the industrial, agricultural and other biological activities could provide a cost-effective technique. The nanomaterials synthesized from such waste not only minimizes the pollution but also provides an eco-friendly approach towards the utilization of the waste. In the present review work, the emphasis has been given on the types of nanomaterials, different methods for the synthesis of 2D nanomaterials from the waste generated from industries, agriculture and their application in electronics, medicine and catalysis.
Subject: Chemistry, Physical Chemistry Keywords: CO2 capture; Activated carbon; Carbon nanomaterials; Adsorption; Surface area.
Online: 8 April 2020 (11:37:06 CEST)
Carbon dioxide (CO2), a major greenhouse gas, capture and separation has recently become a crucial technological solution to reduce atmospheric emissions from fossil fuel burning. Thereafter, many efforts have been put forwarded to reduce the burden on climate change by capturing and separating them especially from larger power plants by the utilization of different technologies. Those technologies have often suffered from high operating cost and huge energy consumption. On right side, physical process such as adsorption is very cost effective process which have been widely used to adsorb different contaminants including CO2. Henceforth, this review covers the overall efficacies of CO2 capture by the utilization of carbon based materials through adsorption technology. Subsequently, we also address the associated challenges and future opportunities of carbon based materials (CBMs). For CO2 capture, it was found that CBMs followed the order of carbon nanomaterials (i.e., graphene, graphene oxides, carbon nanotubes and their composites) < mesoporous -microporous or hierarchical porous carbons < biochar and activated biochar < activated carbons.
ARTICLE | doi:10.20944/preprints201805.0452.v1
Subject: Social Sciences, Other Keywords: transportation; carbon emission; carbon intensity; panel data analysis; China
Online: 30 May 2018 (16:16:35 CEST)
China’s transportation industry has made rapid progress, which has led to a mass of carbon emissions. However, it is still unclear how the carbon emission from transport sector is punctuated by shifts in underlying drivers. This paper aims to examine the process of China’s carbon emissions from transport sector as well as its major driving forces during the period of 2000 to 2015 at the provincial level. We firstly estimate the carbon emissions from transport sector at the provincial level based on the fuel and electricity consumption using a top-down method. We find that the carbon emission per capita is steadily increasing across the nation, especially in the provinces of Chongqing and Inner Mongolia. However, the carbon emission intensity is decreasing in most provinces of China, except in Yunnan, Qinghai, Chongqing, Zhejiang, Heilongjiang, Jilin, Inner Mongolia, Henan and Anhui. We then quantify the effect of socio-economic factors and their regional variations on the carbon emissions using panel data model. The results show that the development of secondary industry is the most significant variable in both the entire nation level and the regional level, while the effects of the other variables vary across regions. Among these factors, population density is the main motivator of the increasing carbon emissions per capita from transport sector for both the whole nation and the western region, whereas the consumption level per capita of residents and the development of tertiary industry are the primary drivers of per capita carbon emissions for the eastern and central region.
Subject: Materials Science, General Materials Science Keywords: carbon; atomic structure; electron-dynamics; potential energy; force-exertion; atomic binding
Online: 17 May 2019 (08:36:23 CEST)
Many studies discuss carbon-based materials because of the versatility of its element. They include different opinions for scientific problems and discuss fairly at convincing and compelling levels within the scope and application. A gas-state carbon atom converts into various states depending on its conditions of processing. The electron transfer mechanism in the gas-state carbon atom is responsible to convert it into various states, namely, graphite, nanotube, fullerene, diamond, lonsdaleite and graphene. The shape of ‘energy trajectory’ enables transferring electrons from the left- and right-sides of an atom is like a parabola. That ‘energy trajectory’ is linked to states (filled state and suitable nearby unfilled state) where force-exertion along the poles of transferring electrons is remained balance. So, the mechanism of originating different states of a gas-state carbon atom is under the involvement of energy first. This is not the case for atoms executing confined inter-state electron-dynamics as the force is involved first. Graphite-, nanotube- and fullerene-state atoms ‘partially evolve partially develop’ (form) their structures. These possess one-dimensional, two-dimensional and four-dimensional ordering of atoms, respectively. Their structural formation also comprises ‘energy curve’ having a shape-like parabola. Transferring suitable filled state electron to suitable nearby unfilled state is under a balance force exerting along the poles. The graphite structure under only attained-dynamics of atoms can also be formed but in two-dimension. Here, binding energy between graphite-state carbon atoms is for a small difference of exerting forces along their opposite poles. Structural formation in diamond, lonsdaleite and graphene atoms involve energy to gain required infinitesimal displacements of electrons through which they maintain orientationally-controlled exerting forces along dedicated poles. In this study, the growth of diamond is found to be south to east-west (ground) where atoms bound ground to south. Thus, diamond atoms merge for a tetra-electron ground to south topological structure. Lonsdaleite atoms merge for a bi-electron ground to just-south topological structure. The growth of graphene is found to be north to ground where atoms bound ground to north. Thus, graphene atoms merge for a tetra-electron ground to north topological structure. Glassy carbon exhibits layered-topological structure where, tri-layers of gas-, graphite- and lonsdaleite-state atoms successively bind in repetitive order. Nanoscale hardness is also sketched based on different force-energy behaviors of different state carbon atoms. Here, structure evolution in each carbon state atom explores its own science.
ARTICLE | doi:10.20944/preprints201703.0169.v1
Subject: Social Sciences, Econometrics & Statistics Keywords: China; sustainability development; carbon emissions; carbon flow; sectoral analysis
Online: 21 March 2017 (04:28:01 CET)
Reducing carbon emissions is a major ways to achieving green development and sustainability for China’s future. This paper elaborates the detailed feature of China's carbon flow for 2013 with the carbon flow chart and gives changing characteristics of China's CO2 flow from the viewpoint of sector and energy during 2000 and 2013. The results show that (1) during 2000 to 2013, China's CO2 emissions with the approximately growth portion of 9% annually, while the CO2 intensity of China diminishes at different rates. (2) The CO2 emissions from secondary industry are prominent from the perspective of four main sectors accounting for 83.5%. The manufacturing play an important part in the secondary industry with 45%. In which the "smelting and pressing of metal" takes up a large percentage as about 50% in manufacturing. (3) The CO2 emissions produced by coal consumption is keep dominant in energy-related emissions with a contribution of 65%, while it will decrease in the future. (4) From the aspect of sector, the CO2 emissions mainly come from the "electricity and heating" sector and the "smelting and pressing of metals" sub-sector. While it is essential and urgent to propose concrete recommendations for CO2 emissions mitigation. Firstly, the progression of creative technology is inevitable and undeniable. Secondly, the government should make different CO2 emissions reduction policies among different sectors. For example, the process emission plays an important role in "non-metallic mineral" while in "smelting and manufacturing of metals" it is energy. Thirdly, the country can change the energy structure and promote renewable energy for powering by wind or other low-carbon energy. Besides it, the coke oven gas can be a feasible substitution. Finally, policy maker should be aware of the emissions from residents have been growing in a fast rate. It is effective to involve the public in the activity of energy conservation and carbon emissions reduction such as reducing the times of personal transportation.
COMMUNICATION | doi:10.20944/preprints202208.0360.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Thermal Infrared satellite data; carbon monoxide; boreal fires; carbon dioxide
Online: 19 August 2022 (08:27:04 CEST)
Biomass burning is an important and changing component of the global and hemispheric carbon cycles. Boreal forest fires in Russia and Canada are significant sources of greenhouse gases carbon dioxide (CO2) and methane (CH4). The influence of carbon monoxide (CO) on the greenhouse effect is practically absent: its main absorption bands of 4.6 and 2.3 μm are far away from the climatically important spectral regions. Meanwhile, CO concentrations in fire plumes are closely related to CO2 and CH4 emissions from fires. On the other hand, satellite measurements of CO are much simpler than those for the aforementioned gases. The Atmospheric Infrared Sounder (AIRS) provides a satellite-based CO data set since October, 2002 up to now. This communication presents estimates of CO emissions from biomass burning north of 30° N using a simple two-box mass-balance model. These results correlate closely with independently estimated CO emissions from the GFED4 bottom-up data base. Both ones reported record high emissions in 2021 throughout two decades, double the annual emissions comparing to the previous years. There have been two years with extremely high emissions (2003 and 2021), but for the rest of data upward trend with a rate of 3.6 ± 2.2 Tg CO yr-2 (4.8 ± 2.7% yr-1), was found. A similar rate of CO emission follows from the GFED4 data.
ARTICLE | doi:10.20944/preprints202206.0070.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Thermal Infrared satellite data; carbon monoxide; boreal fires; carbon dioxide
Online: 6 June 2022 (08:39:43 CEST)
Biomass burning is an important and changing component of the global and hemispheric carbon cycles. In particular, boreal forest fires in Russia and Canada are important sources of greenhouse gases carbon dioxide (CO2) and methane (CH4). The influence of carbon monoxide (CO) on the climate is insignificant: its main absorption bands of 4.6 and 2.3 μm are far away from the climatically important regions of the spectrum. Meanwhile, CO concentrations in fire plumes are closely related to CO2 and CH4 emissions from fires. On the other hand, satellite measurements of CO are much simpler than those for the aforementioned gases. The Atmospheric Infrared Sounder (AIRS) provides a long satellite-based CO data set. This article presents estimates of CO emissions from biomass burning north of 30° N using a simple two-box model. These results correlate closely with independently estimated CO emissions from the GFED4 bottom-up data base. Both ones reported record high emissions in 2021 throughout two decades, double the annual emissions comparing to the previous a few years. There have been several years with extreme emissions, but for the rest of data upward trend with a rate of 3.7 ± 2.3 Tg CO yr-2 (4.4 ± 2.8% per year), was found.
ARTICLE | doi:10.20944/preprints202107.0439.v2
Subject: Biology, Anatomy & Morphology Keywords: capital return rate deficiency; expected value; carbon storage; carbon rent; albedo effect
Online: 2 August 2021 (13:28:23 CEST)
Two sets of initial conditions are used in the investigation of capital return rate and carbon storage in boreal forests. Firstly, a growth model is applied in young stands as early as the inventory-based model is applicable. Secondly, the growth model is applied to observed wooded stands. Four sets of thinning schedules are investigated in either case. First, the capital return rate is aspired without any restriction. Second, the number of thinnings is restricted to at most one. Third, thinnings are restricted to the removal of only trees thicker than 237 mm. Fourth, commercial thinnings are omitted. The two sets of initial conditions yield similar results. The capital return rate is a weak function of rotation age, which results in variability in the optimal number of thinnings. Reducing the number of thinnings to one increases timber stock but induces a capital return rate deficiency. The deficiency per excess volume unit is smaller if the severity of any thinning is restricted by the removal of large trees only. Omission of thinnings best applies to spruce-dominated stands with stem count less than 2000/ha. Restricted thinning intensity applies to deciduous stands and dense pine stands. The albedo effect increases the benefits of restricted thinnings and increased clearcuttings instead of contradicting the carbon storage.
ARTICLE | doi:10.20944/preprints202009.0102.v1
Subject: Earth Sciences, Environmental Sciences Keywords: forest carbon cycle; climate change mitigation; plantation foestry; soil carbon
Online: 4 September 2020 (12:14:53 CEST)
Forest plantations have a large potential for carbon sequestration, playing an important role in the global carbon cycle. However, despite the huge amount of research carried out worldwide, the absolute contribution of industrial forest plantations is still incomplete for some parts of the world. To contribute to bridge this gap, we calculated the amount of C stock in three fast growing forest species in Chile. Relevant C pools (above-ground and below-ground biomass, forest floor, and soil) were considered for this analysis. Across the industrial plantation forests of Chile, carbon accumulated in the above-ground biomass was 181–212 Mg · ha−1 for Pinus radiata, 147–180 Mg · ha−1 for Eucalyptus nitens, and 95–117 Mg · ha−1 for Eucalyptus globulus (age 20–24 years for P.radiata and 10–14 years for Eucalyptus). Our results agree with other studies showing that 30%–50% of the total C stock is stored in the soil. Total C stocks were for 343 Mg · ha−1 for P.radiata, 352 Mg · ha−1 for E.nitens, and 254 Mg · ha−1 for E. gloubulus, also at the end of a typical rotation. The carbon pool in the forest floor was found to be significantly lower (less than 4% of the total) when compared to the other pools and showed large spatial variability. We conclude that industrial forest plantations are a valuable tool to reduce atmospheric CO2 and mitigate climate change. Given the contribution of soils to total carbon stocks, special attention should be paid to forest management activities that affect the soil organic carbon pool.
ARTICLE | doi:10.20944/preprints202208.0281.v1
Subject: Materials Science, Nanotechnology Keywords: nanobelts; tin oxide; gas sensor; carbon monoxide; carbon dioxide; CO; CO2
Online: 16 August 2022 (07:43:01 CEST)
When present in specific amounts in the air, the colorless, odorless, and tasteless gases monoxide and carbon dioxide may either replace oxygen in red blood cells (CO) or increase the respiratory rate causing cardiac arrhythmias (CO2), leading to death. Commercial sensors take around 8 h to detect levels of CO (50 PPM), causing moderate poisoning. SnO2 presents controlled interactions with the atmosphere using conductance and vacancy adjustments to capture electrical properties. However, the selectivity of gas detection by SnO2 can still be improved, thus also increasing the application possibilities. The present study aimed to optimize the sensing of CO and CO2 in SnO2 using palladium functionalization. The vapor-liquid-solid method synthesized a network of SnO2 nanobelts decorated with palladium nanoparticles. The sensitivity of the sensors for CO and CO2 were evaluated, characterizing parameters such as response time, a wide range of CO and CO2 concentrations, and temperature. In the seventh measurement cycle, the sensor response for different concentrations of gases in consecutive cycles showed a sensitivity of up to 125% for CO in 60 s. Furthermore, we observed increased sensor sensitivity with material doping with nanoparticles from 130 ppm to 1360 ppm in 30 seconds to CO. Conclusion: The results provide a better understanding of the sensitivity of SnO2 in palladium-decorated nanoparticles, offering insights for detecting low CO concentrations quickly. The behavior of these doped nanosensors showed us the importance of considering them as a practical possibility for detecting these gases of importance to human health.
REVIEW | doi:10.20944/preprints202009.0236.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Biogeochemistry; Carbon; Carbon balance; Ecosystem; Ecosystem processes; Mangrove; Salt marsh; Wetland
Online: 10 September 2020 (11:22:38 CEST)
Mangroves and salt marshes are among the most productive ecosystems in the global coastal ocean. Mangroves store more carbon (739 Mg CORG ha-1) than salt marshes (334 Mg CORG ha-1), but the latter sequester proportionally more (24%) net primary production (NPP) than mangroves (12%). Mangroves exhibit greater rates of gross primary production (GPP), above-ground net primary production (NPP) and plant respiration (RC) with higher PGPP/RC ratios, but salt marshes exhibit greater rates of below-ground NPP. Mangroves have greater rates of subsurface DIC production and, unlike salt marshes, exhibit significant microbial decomposition to a soil depth of 1 m. Salt marshes release more soil CH4 and export more dissolved CH4 , but mangroves release more CO2 from tidal waters and export greater amounts of POC, DOC and DIC to adjacent waters. Both ecosystems contribute only a small proportion of GPP, RE (ecosystem respiration) and NEP (net ecosystem production) to the global coastal ocean due to their small global area, but contribute 72% of air-sea CO2 exchange from the world’s wetlands and estuaries and contribute 34% of DIC export and 17% of DOC + POC export to the world’s coastal ocean. Thus, both wetland ecosystems contribute disproportionately to carbon flow of the global coastal ocean.
ARTICLE | doi:10.20944/preprints202008.0335.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Biomass burning; SMOKE; NCO; GFASv1.3; Black carbon; Organic carbon; Southern Hemisphere
Online: 15 August 2020 (04:19:14 CEST)
Wildfires generate large amounts of atmospheric pollutants yearly. The development of an emissions inventory for this activity is a challenge today, mainly to perform modeling of air quality. There are free available databases with historical information about this source. The main goal of this study was to process the results of biomass burning emissions for the year 2014 from the Global Fire Assimilation System (GFAS). The pollutants studied were the black carbon, the organic carbon, fine and coarse particulate matter, respectively. The inputs were pre-formatted to enter to the simulation software of the emission inventory. In this case, the Sparse Matrix Operator Kernel Emissions (SMOKE) was used and the values obtained in various cities were analyzed. As a result, the spatial distribution of the forest fire emissions in the Southern Hemisphere was achieved, with the polar stereographic projection. The highest emissions were located in the African continent, followed by the northern region of Australia. Future air quality modeling at a local level could apply the results and the methodology of this study. The biomass burning emissions could add a better performance of the results and more knowledge on the effect of this source.
ARTICLE | doi:10.20944/preprints202004.0544.v1
Subject: Biology, Ecology Keywords: ecological restoration; illegal mining; Clean Development Mechanism; carbon sequestration; carbon credits
Online: 30 April 2020 (17:24:36 CEST)
Ghana has had a long-standing problem of illegal gold mining that has led to the destruction of the environment. The government of Ghana is taking steps to not only curb illegal mining but also to restore destroyed lands that resulted from illegal mining. The government intends to spend financially in the area of ecological restoration to returned disturbed lands to their natural states possible, but the question remains whether restoring those disturbed lands will be beneficial to the country. The study was undertaken in Bekwai Municipal Area in the Ashanti region of Ghana where most locals are farmers. The research studies whether the benefits of ecological restoration outweigh the cost of ecological restoration? The research deployed a quantitative data collection. The data collected was analyzed using benefit-Cost ratio. The result shows that the benefit of ecological restoration outweighs the cost incurred as dependent on the land use as a carbon sequestration project. In conclusion, investment in ecological restoration is a step in the right direction for a country endowed with gold resources. This will spur growth and at the same time improve and protect the country’s natural resources and environment.
ARTICLE | doi:10.20944/preprints201807.0385.v2
Subject: Social Sciences, Other Keywords: low carbon island; electric motorcycles; green transport; battery exchange; carbon emissions
Online: 5 September 2018 (16:23:53 CEST)
Global warming and climate change have led to extreme changes in climatic conditions in recent years. The Taiwan government designates the construction of the Kinmen County as low carbon islands, to promote the operation of 100 electric motorcycles and battery demonstration. This study combined with island tourism, after boarding the island, visitors can rent electric motorcycles from the passenger service center and coordinate with the island tour map to show the location of the battery exchange points, so as to facilitate the search. During the operation, the amount of electric motorcycle lease is 15,551 times, the total mileage of motor vehicle is 284,404 km, the number of battery exchange is 622 times, the lease income is about NT$900,000. To reduce carbon and economic benefits of the assessment, compared to the motorcycles (50 c.c), electric motorcycles (EM 100) can reduce the carbon emissions by 8,726 kg, reducing energy costs of NT$422,594.
ARTICLE | doi:10.20944/preprints201806.0210.v1
Subject: Chemistry, Analytical Chemistry Keywords: carbon graphite; crystal cubic carbon; M-polynomial; Zagreb index; Randic index
Online: 13 June 2018 (10:58:44 CEST)
Graph theory plays a crucial role in modeling and designing of chemical structure or chemical network. Chemical Graph theory helps to understand the molecular structure of molecular graph. The molecular graph consists of atoms as vertices and bonds as edges. Topological indices capture symmetry of molecular structures and give it a mathematical language to predict properties such as boiling points, viscosity, the radius of gyrations etc. In this article, we study the chemical graph of carbon Crystal structure of graphite and cubic carbon and compute several degree-based topological indices. Firstly we compute M-Polynomials of these structures and then from these M-polynomials we recover nine degree-based topological indices.
ARTICLE | doi:10.20944/preprints201803.0207.v1
Subject: Biology, Ecology Keywords: above-ground carbon stock; below-ground carbon stock; soil nutrients; exclosure
Online: 26 March 2018 (08:17:48 CEST)
Exclosures are used to regenerate native vegetation as a way to reduce soil erosion, increase rain water inﬁltration and provide fodder and woody biomass in degraded grazing lands. Therefore, this study assessed the impact of grazing exclosure on vegetation biomass, carbon sequestration and soil nutrients under five and ten years of grazing exclosures and freely grazed areas in Tigray, northern Ethiopia. Vegetation biomass, carbon stocks and soil nutrients increased with increasing grazing exclusion. However, open grazing lands and five years of grazing exclosure did not differ in aboveground biomass, above-and-belowground carbon stocks. Moreover, ten years of grazing exclosure had a higher (P<0.01) grass, herb and litter carbon stocks compared to five years exclosure and open grazing lands. The total carbon stock was higher for ten years exclosure (193.3 t C ha-1) than the five years exclosure (154.0 t C ha-1) and in open grazing areas (146.6 t C ha-1). Grazing lands closed for ten years had a higher SOC, organic matter, total N, available P, and exchangeable K+ and Na+ compared to five year’s exclosure and open grazing lands. Therefore, establishment of grazing exclosures had a positive effect in restoring degraded grazing lands, thus improving vegetation biomass, carbon sequestration potentials and soil nutrients under the changing climate and global warming.
ARTICLE | doi:10.20944/preprints201612.0020.v1
Subject: Biology, Forestry Keywords: natural secondary forest; planted forest; vegetation biomass carbon; soil organic carbon
Online: 3 December 2016 (09:25:48 CET)
Forest ecosystems make a greater contribution to carbon (C) stocks than any other terrestrial ecosystem. To understand the role of regional forest ecosystems in global climate change and carbon exchange, forest C stock and its spatial distribution within the small (2,300 km2) Liuxihe River basin were analyzed to determine the different contributors to the C stock. Forest C stocks were quantified by measuring the biomass of trees, understory vegetation, litter and roots, as well as soil organic C, using data from field samples and laboratory experiments. The results showed that forests stored 38.04 Tg C in the entire basin, with secondary and planted forests accounting for 89.82% and 10.18%, respectively, of the stored C. Five types of forests, a subtropical evergreen broad-leaved forest, a subtropical coniferous and broad-leaved mixed forest, a subtropical coniferous forest, a timber forest, and a non-wood forest, stored 257.55 ± 15.01, 218.92 ± 9.59, 195.24 ± 18.29, 177.42 ± 17.55, and 117.86 ± 6.04 Mg C ha−1, respectively. In the forest ecosystem C stocks of the basin, soils averagely contribute about 73.78%, not including root underground biomass. It provides a comprehensive method for forest ecosystem carbon investigation and forest management in small basin scale.
ARTICLE | doi:10.20944/preprints202212.0258.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Humus; soil biota; organic soil carbon; atmospheric CO2; carbon credits and deficits
Online: 14 December 2022 (14:02:26 CET)
Land’s basic biota metric is soil organic carbon (SOC) yet global estimates range 1,417–15,000 Gt C. Erosion of ancient topsoil and loss of vital soil taxa are most urgent – and most ignored – of all context-triaged concerns. Albeit topographical terrain increases most soil calculations and inventories on a non-flat Earth, re-evaluation shows the major contribution to unrelenting atmospheric CO2 increase more from topsoil loss than fossil fuels. Although increased CO2 has resulted in a global greening effect with NPP productivity now ~220 Gt C/yr, this is arguably outweighed by more rapid erosion of topsoil and expansion of desertification at 2-15 Gt SOC/yr volatilized due to excessive meat eating with unsupportable soil extractive, toxic farm management. In particular excess synthetic Nitrogen acidifies topsoil and depletes the organic SOC biotic-dynamics. Carbon credits of our disappearing soil biotic stocks are enumerated for plant roots (916 Gt C), litter (600 Gt C), microbes (200 Gt C), fungi (30 Gt C), biocrust (10-20 Gt C), earthworms (2.3-3.6 Gt C), termites (0.15 Gt C), nematodes (0.06 Gt C), ants (0.024 Gt C), and soil viruses (0.02–4.0 Gt C). Consideration of soil microbes and review of global SOC inventories reveal critical topsoil loss up to 20,000 tonnes per second with species extinction as high as 23 taxa each second. Sustainable Development Goals (SDGs) fail without a solid soil foundation. However, heritage soil data points to remedy in modern organic farm restoration. Safe solution is via natural vermi-composting, 100% organic farming, and Permaculture under a simple logical premise that the Problem (i.e., SOC loss) is the Solution (viz., SOC restoration).
ARTICLE | doi:10.20944/preprints202104.0320.v1
Subject: Mathematics & Computer Science, Algebra & Number Theory Keywords: Carbon neutral; Equator Principle; Industrial Bank; "Three Principles"; Factor Analysis; Carbon neutral
Online: 12 April 2021 (14:32:36 CEST)
The Equator Principle is the goal of promoting the harmonious development of my country's economy and society. It promotes the green transformation and upgrading of the industrial structure by strictly controlling the flow of commercial bank funds, so as to achieve the goal of environmental protection and the coordinated development of the national economy. This paper uses factor analysis to reduce the dimensions of 10 financial indicators and non-financial indicators that measure the operating performance and development potential of joint-stock commercial banks, and then compares the comprehensive operating performance, liquidity, and safety of Industrial Bank and comparable banks. And the level of profitability, analyze the difference in comprehensive operating performance of joint-stock commercial banks joining the Equator Principles compared with commercial banks that have not joined the Equator Principles. The results of the study found that joining the Equator Principles of joint-stock commercial banks can improve comprehensive operating performance in the short term. In the long run, the development trend of Industrial Bank will be similar to that of comparable banks in the same category. Joining the Equator Principles of Industrial Bank can improve its liquidity and profitability, but it will not in the long run. Conducive to the improvement of the asset quality of joint-stock commercial banks. In this regard, the government, enterprises and financial institutions should work together to help commercial banks achieve an effective balance between operating performance and social responsibility, so as to achieve the goals of "carbon peak" and "carbon neutral".
ARTICLE | doi:10.20944/preprints202101.0362.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Elemental carbon; Secondary organic carbon; Health impact; Polycyclic aromatic hydrocarbon; Northeasterly monsoon
Online: 18 January 2021 (17:27:22 CET)
With increasing interest in understanding contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the City of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analysed for water soluble organic carbon (WSOC), organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analysed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC and EC were 2.7 ± 2.2 (range of 0.63-9.1) µg/m3, 6.9 ± 4.9 (3.1-24.1) µg/m3 and 3.7 ± 1.6 (1.3-6.8) µg/m3, respectively, with estimated average SOC of 2.3 µg/m3, contributing 34% to total OC. The average of total PAHs was 1.8 ± 2.7 ng/m3. Source identification methods revealed natural gas and biomass burning, and urban traffic combustion as dominant sources of PAHs in Kuala Lumpur. To understand human health risk posed by PAHs, a deterministic screening health risk assessment was also conducted for several age groups including infant, toddler, children, adolescent and adult. The total concentration of BaPeq is 3.8 ng/m3, with the average of 0.29 (range of 0.001-1.6) ng/m3. Carcinogenic and non-carcinogenic risk of PAH species were well below the acceptable levels recommended by the USEPA. Future work is needed using long-term monitoring data to understand the origin of PAH contributing to SOA formation and to apply source-risk apportionment to know better the potential risk factors posed by the various sources in urban areas in Kuala Lumpur.
ARTICLE | doi:10.20944/preprints201911.0154.v1
Subject: Earth Sciences, Environmental Sciences Keywords: calcareous soil; plantation ages; organic carbon mineralization; fitting parameters; organic carbon accumulation
Online: 14 November 2019 (09:17:50 CET)
Soil organic carbon (SOC) mineralization is closely related to carbon source or sink of terrestrial ecosystem. Understanding soil organic carbon (SOC) mineralization under plum plantation is essential for improving our understanding of SOC responses to land-use change in karst rocky desertification ecosystem. In this study, 2-y, 5-y and 20-y plum plantations and adjacent woodland were sampled and a 90-day incubation experiment was conducted to investigate the effect of plum plantation with different years on SOC mineralization in subtropical China. Results showed that: (1) there was no significant difference in SOC content between different planting years, but there were significant differences in accumulative SOC mineralization (Ct) and potential SOC mineralization (C0); (2) the dynamics of the SOC mineralization was a good fit to a first-order kinetic model. Both C0 and Ct in calcareous soil of this study was several to ten folds lower than that in other soils, indicating that SOC in karst region has higher stability. (3) Correlation analysis revealed that both Ct and C0 was significantly correlated with soil calcium (Ca) and C/N, indicating the important role of Ca and C/N in SOC mineralization in karst rocky desertification area.
Subject: Biology, Agricultural Sciences & Agronomy Keywords: carbon sequestration; methane; carbon dioxide; nitrous oxide; global warming potential; paddy field
Online: 23 June 2019 (13:54:38 CEST)
Three rice paddy fields under farmers’ actual management conditions were investigated from May to April at Bibai (43°18′N, 141°44′E), in central Hokkaido, Japan to evaluate the carbon (C) sequestration and contribution of CO2, CH4 and N2O fluxes to a global warming potential (GWP). CH4 and N2O fluxes were measured by placing the chamber over the rice plants covering four hills and CO2 fluxes from rice plants root free space in paddy fields were taken as an indicator of soil microbial respiration (Rm) using the closed chamber method. Annual cumulative Rm ranged from 422 to 519 g C m-2 yr-1; which accounted for 54.7 to 55.5 % mainly during the rice growing season. Annual cumulative CH4 emission ranged from 75.5 to 116 g C m-2 yr-1 and this contribution occurred entirely during the rice growing period. Annual cumulative N2O emission ranged from 0.091 to 0.154 g N m-2 yr-1 and 73.5 to 81.3% of the positive annual N2O emission observed during the winter-fallow season. Soil C sequestration was estimated as the difference between net primary production (NPP) and C loss through Rm, CH4 emission and crop C harvest. The soil C sequestration ranged from -305 to -365 g C m- 2 yr-1, indicating that the C loss could not be compensated for by C input through NPP. Carbon loss was much higher (62 to 66%) in winter-fallow season than growing season. The annual net GWP from the investigated paddy fields ranged from 3823 to 5016 g CO2 equivalent m-2 yr-1. Annual GWPCH4 accounted for 71.9 to 86.1% of the annual net GWP predominantly from the rice growing period. These results indicate that CH4 dominated the rice paddy’s net GWP.
ARTICLE | doi:10.20944/preprints201810.0668.v1
Subject: Engineering, Other Keywords: climate change; carbon emissions; low carbon city; sustainability; strategy-based model; SLCM
Online: 29 October 2018 (09:55:25 CET)
Low carbon cities are increasingly forming a distinct strand of sustainability literature. Models have been developed to measure the performance of low carbon cities. The purpose of this paper is to formulate a strategy-based model to evaluate current performance and predict future conditions of low carbon cities. It examines the dynamic interrelationships between key performance indicators (KPIs), induces changes to city plan targets and then instantly predicts the outcome of these changes. Designed generic and flexible, the proposed model shows how low carbon targets could be used to guide the transformation of low carbon cities under four strategies: (1) passive intervention, (2) problem solving, (3) trend modifying and (4) opportunity seeking. Further, the model has been applied to 17 cities and then tested on 5 cities: London, New York, Barcelona, Dubai and Istanbul. The paper concludes with policy implications to realign city plans and support low carbon innovation.
REVIEW | doi:10.20944/preprints201801.0166.v1
Subject: Materials Science, General Materials Science Keywords: carbon clathrates; hybrid carbon-silicon clathrates; hybrid carbon-nitrogen clathrates; electrode materials; hydrogen storage materials; energy storage materials; hard materials
Online: 18 January 2018 (05:08:03 CET)
Hybrid carbon-silicon, carbon-nitrogen, and carbon-boron clathrates are new classes of Type I carbon-based clathrates that have been identified by first-principles computational methods by substituting atoms on the carbon clathrate framework with Si, N, and/or B atoms. The hybrid framework is further stabilized by embedding appropriate guest atoms within the cavities of the cage structure. Series of hybrid carbon-silicon, carbon-boron, carbon-nitrogen, and carbon-silicon-nitrogen clathrates have been shown to exhibit small positive values of the energy of formation, indicating that they may be metastable compounds and amenable to fabrication. In this overview article, the energy of formation, elastic properties, and electronic properties of selected hybrid carbon-based clathrates are summarized. Theoretical calculations that explore the potential applications of hybrid carbon-based clathrates as energy storage materials, electronic materials, or hard materials are presented. The computational results identify compositions of hybrid carbon-silicon and carbon-nitrogen clathrates that may be considered candidate materials for use as either electrode materials for Li-ion batteries or as hydrogen storage materials. Prior processing routes for fabricating selected hybrid carbon-based clathrates are highlighted and difficulties encountered are discussed.
ARTICLE | doi:10.20944/preprints202110.0374.v1
Subject: Materials Science, Biomaterials Keywords: Oxygen reduction reaction; Nanoporous activated carbon; Cobalt-nitrogen-doped carbon; Nonprecious metal catalyst
Online: 26 October 2021 (11:34:57 CEST)
Compared with precious metal catalysts, non-platinum catalysts have the advantages of low cost and high performance. Among them, the activated carbon (AC) with a large specific surface area (SSA) can be used as a carrier or as a carbon source of nonprecious metal/carbon system catalyst at the same time. Therefore, this paper uses cheap pine peel bio-based materials to prepare large surface area activated carbon and then compound with cobalt phthalocyanine (CoPc) to obtain a high-performance cobalt/nitrogen/carbon catalyst. The merits include AC@CoPc composite catalysts are prepared by precisely controlling the composite proportion of AC and CoPc, the atomically dispersed Co nanoparticles form and synergistically with N promote the exposure of CoNx active sites, and the Eonset of the catalyst treated with a composite proportion of AC and CoPc of 1 to 2 at 800 °C (AC@CoPc-800-1-2) is 1.01 V, which is higher than Pt/C (20 wt%) catalyst. Apart from this, the stability is 87.8% in 0.1 M KOH after 20000 s testing in compared with other AC@CoPc series catalysts and Pt/C (20 wt%) catalyst. Considering from the performance and price of the catalyst in practical application, these composite catalysts combine biomass carbon materials with phthalocyanine series, which will be widely used in the area of nonprecious metal catalysts.
ARTICLE | doi:10.20944/preprints202108.0128.v1
Subject: Materials Science, Biomaterials Keywords: Carbon foam; multi walled carbon nanotubes; Graphene oxide; electrical; mechanical and thermal properties
Online: 5 August 2021 (08:36:50 CEST)
Multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) reinforced carbon foam (CF) composite were prepared by direct pyrolysis of MWCNTs, GO and mesophase coal tar pitch. The effect of additive amount of the mixture of MWCNTs and GO on the microstruture and properties of carbon foam was analzyed by transmission electron miscroscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Four-probe resistance meter, universal testing machine, and laser thermal conductivity tester respectively. The result shows that MWCNTs and GO had significant impact on the microstructure of carbon foam. Futhermore, the electrical, mechanical and thermal properties of carbon foam composites were significantly enhanced by increasing the additive amount. Maximum compressive strenght of 19.2 MPa and Young’s modulus of 56.8 MPa of CF composite were observed. Similarly, Highest thermal conductivity of 30.91 W/m.K and electrical conductivity of 27.2 ×103 S/m were observed at 2 wt. % of MWCNTs-GO additive loading.
ARTICLE | doi:10.20944/preprints202011.0383.v1
Subject: Biology, Anatomy & Morphology Keywords: capitalization; capital return rate deficiency; expected value; carbon storage; timber stock; carbon rent
Online: 13 November 2020 (13:49:46 CET)
An empirical model for log yield from trees is established and applied in microeconomics of carbon storage in a boreal spruce estate. The transition from pulpwood to sawlogs is a smoother function of stem diameter in the empirical data, in comparison to literature values. Correspondingly, the value transition of trees along with increasing size is gentler. Due to price premium of sawlogs from clearcuttings, all economically feasible treatment schedules terminate in clearcutting. Best capital return rates are gained with two heavy thinnings from above before clearcutting. Present carbon emission prices allow moderate carbon storage increment if the increment is compensated by proportional carbon rent. Doubling the present carbon prices would allow strong carbon storage increments if compensated by carbon rent. Application of nonproportional carbon rent is proposed.
ARTICLE | doi:10.20944/preprints202008.0278.v1
Subject: Engineering, Construction Keywords: dynamic insulation; heat-exchangers; mass timber; low carbon; carbon utilization; thermally active surfaces
Online: 12 August 2020 (08:39:38 CEST)
Mass timber products, together with careful forestry management, could help decarbonize the construction industry. These products must be long-lasting, to safely store atmospheric carbon for decades or centuries, and multi-functional, to displace materials and equipment that are emissions-intensive. This paper shows how to optimize mass timber panels as heat-exchangers, suggesting how to eliminate insulation while simplifying HVAC systems. Test panels measured the heat-exchange in steady and transient conditions, when the ventilation was driven by a fan or by thermal buoyancy. The total heatexchange was predicted accurately by theory in all cases. Further investigation is needed to understand the possible heat-recovery effects at the exterior surface.
ARTICLE | doi:10.20944/preprints202004.0388.v1
Subject: Biology, Forestry Keywords: Capitalization; capital return rate deficiency; expected value; carbon storage; timber stock; carbon rent
Online: 22 April 2020 (05:33:21 CEST)
The expense of carbon sequestration in terms of capital return deficiency is investigated at estate level, in the case of a fertile boreal estate dominated by spruce forest. Thinnings from below result as a high expense of increased rotation age, thinnings from above as a small expense. The expense of increased timber stock is greater than any proportional carbon rent based on present carbon prices. Application of non-proportional carbon rent is proposed.
REVIEW | doi:10.20944/preprints202102.0346.v1
Subject: Materials Science, Polymers & Plastics Keywords: Activated carbon; Adsorbance; Pyrolysis; Applications
Online: 17 February 2021 (09:15:00 CET)
Actuated carbon (AC) is utilized in various conditions of uses after its disclosure as a solid and dependable adsorbent. A review on AC is introduced along with returning to the wellsprings of AC age; strategies used to produce AC including pyrolysis enactment; actual actuation; synthetic initiation and steam pyrolysis. The significant variables influencing the AC creation, the potential uses of AC and their future possibilities are likewise examined. AC is applied in water, wastewater and leachate medicines in numerous nations, particularly to clean the shading, eliminate the smell and some substantial metals. Taking into account this, an exhaustive rundown of research on compound, physical and organic change strategies of initiated carbon relating to prevent of foreign substance expulsion from watery arrangements was aggregated and investigated. Additionally, the examination of the actual blending strategy and the impregnation technique in enactment with antacid metals shows that the actuated carbon got through actual blending had a higher porosity than the initiated carbon created by the impregnation technique. The uses of initiated carbon items were quickly surveyed.
ARTICLE | doi:10.20944/preprints202008.0147.v1
Online: 6 August 2020 (10:10:43 CEST)
In recent years, the production of cement has grown globally in a very rapid manner due to the modernization of the world we live in, and after fossil fuels and land-use change, cement production is the third-largest source of anthropogenic emissions of carbon dioxide, CO2. Cement being the primary binding material for concrete and with the prospects for the concrete industry continues to grow so will the emissions of CO2. Hence, a method to reduce the CO2 production while keeping up with the progression of the concrete industry is very crucial in current times. This is where CO2 sequestration comes in. It is a process where CO2 is converted into a mineral which will then be trapped into the concrete forever. Required data to carry out the research between CO2 sequestered concrete and concrete without CO2 have been observed, obtained and tabulated as necessary. These data are then used to compare the concrete samples with one another and also prove the theoretical effects of CO2 exposure to concrete. Hence, experimental results on the compressive strength of the concrete samples for 7, 14 and 28 days has also been tabulated, graphed and further disputed. The objective of this research is mainly to determine the compressive strength of CO2 sequestered concrete in comparison with concrete without CO2 in order to decrease the effects the concrete industry has on the environment. The compressive strength of concrete samples with sequestration of CO2 gas is expected to be higher than of the concrete without CO2.
Online: 21 July 2020 (13:40:39 CEST)
Commercially available oxidized (carboxylic groups) and non-oxidized multiwalled carbon nanotubes were studied as adsorbents of cerium(III) in batch operation mode. Several variables affecting the rare earth adsorption were investigated, including: the stirring speed applied to the system, the pH of the solution and the metal concentration and carbon dosages. Although the removal of cerium from the solution is different and dependent upon the adsorbent type: i) adsorption in non-oxidized multiwalled carbon nanotubes, ii) cation exchange in the case of using oxidized multiwalled carbon nanotubes, the adsorption kinetics, the rate law and the isotherm models are the same for both adsorbents: pseudo-second order, film diffusion and Langmuir Type-1, respectively. Cerium is desorbed from loaded adsorbents using acidic solutions.
ARTICLE | doi:10.20944/preprints201911.0203.v1
Online: 17 November 2019 (13:17:04 CET)
The present investigation deals with the adsorption of chromium(III) from alkaline media using multi-walled carbon nanotubes. The adsorption of Cr(III) has been studied under various experimental conditions: stirring speed of the aqueous solution, initial metal and adsorbent concentrations, NaOH concentration in the aqueous solution, and temperature. The rate law indicated that chromium adsorption is well represented by the particle diffusion model, whereas the adsorption process fits to the pseudo-second order kinetic model within an exothermic character. Equilibrium data fit to the Langmuir type-2 equilibrium isotherm in an spontaneous process. Chromium(III) can be eluted from metal-loaded nanotubes using acidic solutions, from which fine chromium(III) oxide pigment can be ultimately yielded.
COMMUNICATION | doi:10.20944/preprints201709.0096.v1
Online: 20 September 2017 (10:55:56 CEST)
Cuboid diamonds are particularly common in the placers of the northeastern Siberian platform but their origin remains unclear. These crystals usually range in color from dark yellow to orange and more interestingly, are characterized by unusual low aggregated nitrogen impurities (non-aggregated C-center) suggesting a short residence time and/or low temperatures at which they have been stored in the mantle. In order to track possible isotopic signature that could help deciphering cuboid diamond's crystallization processes, δ13C values, δ15N values and nitrogen contents have been determined in-situ in three samples using secondary ion mass spectrometry (SIMS), whereas nitrogen aggregation state have been determined by FTIR spectroscopy. The samples fall out the δ13C vs. δ15N field of canonical mantle composition. Different scale of carbon and nitrogen fractionation may produce the observed variations. Alternatively, mixing of mantle and crustal material would obscure initial co-variations of δ13C values with δ15N or nitrogen content.
SHORT NOTE | doi:10.20944/preprints201610.0045.v1
Subject: Chemistry, Organic Chemistry Keywords: carbon disulphide; 1,8-diaminonaphthalene; bisthiourea
Online: 13 October 2016 (04:56:12 CEST)
A new bisthiourea compound, 1,3,1',3'-(dinaphthalene-1,8-diyl)bisthiourea, was synthesized. Its structure was characterized by elemental analysis, FT-IR and 1H-, 13C-NMR and MS spectroscopic techniques.
REVIEW | doi:10.20944/preprints202203.0198.v1
Subject: Earth Sciences, Environmental Sciences Keywords: forest carbon; carbon stock; roundwood harvest; climate change mitigation; life cycle assessment; scenarios; modelling
Online: 15 March 2022 (07:23:46 CET)
Fossil-based emissions can be avoided through using wood in place of non-renewable raw materials as energy and materials. However, increasing wood harvest influences forest carbon stocks. This effect may reduce the overall climate benefit of wood use significantly but is widely overlooked. We carried out a systematic review of simulation studies and compared differences in forest carbon and amount of wood harvested between more and less intensive wood harvest scenarios for three different time perspectives; short (1-30 years), mid (31-70 years) and long (71-100 years). Out of more than 450 reviewed studies 44 provided adequate data. Our results show that increased harvesting reduced carbon stocks over 100 years in temperate and boreal forests roughly 1.6 (stdev 0.9) tC per tC harvested. The value proved to be robust when outliers explicitly influenced by other factors than change in harvest rate, such as increase in fertilization or forest area, were removed. Interestingly, no significant difference in carbon impacts was found for average values of boreal and temperate forests or between short and long time-horizons. However, impacts tend to be greatest in the mid-term. This carbon balance indicator that we estimated can be interpreted as carbon debit of wood harvest in forests. It is significant compared with the typical GHG credits in technosphere generated by avoiding fossil emissions in substitution and increase in carbon storage in harvested wood products, and should not be ignored. Our estimates provide default values that can directly be included in GHG balances of products or assessment of mitigation policies and measures related to wood use. However, more systematic scenarios and transparent data in which different factors influencing forest carbon stocks are separately studied are clearly required to provide better constrained estimates for specific forest types.
ARTICLE | doi:10.20944/preprints201901.0328.v1
Subject: Social Sciences, Other Keywords: built environment efficiency; CASBEE; MURNInets; climate change; low carbon; carbon emission; urban tools; city
Online: 31 January 2019 (14:18:50 CET)
CASBEE-City tool determines the city’s Built Environment Efficiency (BEE) by calculating the improvement of Quality of Life (Q) over human activities’ Environmental Load (L) within the city’s hypothetical boundary. A total of 58 variables (57 Q indicators and one variable for L) are used in the worldwide version of CASBEE-City which were grounded using ISO 37120:2014 Sustainable Development of Communities and 17 Sustainable Development Goals (SDGs) by the United Nations (UN). This paper examines the application of CASBEE-City for Malaysian cities using the case of Johor Bahru City and identifies assessment indicators which are customised based on the data availability, reliability and suitability through focus group discussions (FGDs) which involved 36 respondents (researchers, urban planners and stakeholders). This paper reveals Johor Bahru with moderate score B+ in 2010 and 2025. Consensus were also achieved from the 36 FGD respondents for the practicability and future potential of CASBEE-City and BEE framework in Johor Bahru.
ARTICLE | doi:10.20944/preprints201810.0508.v1
Subject: Earth Sciences, Environmental Sciences Keywords: craft brewery, greenhouse gas accounting, carbon regulation, carbon footprint, cap and trade, institutional theory
Online: 22 October 2018 (15:40:11 CEST)
A growing number of companies in the brewery industry have made commitments to measure and reduce their greenhouse gas (GHG) emissions. However, many brewers, particularly craft brewers with relatively low rates of production, have struggled to meet these commitments. The purpose of this research was to investigate the challenges and benefits of measuring and reducing GHG emissions in the craft brewery industry. The research was conducted in Ontario, Canada, which has seen strong recent growth in the craft brewery industry. A case study and semi-structured interviews among Ontario Craft Brewers were conducted. The case study found that indirect (scope 3 emissions under the WBCSD & WRI GHG Protocol) GHG sources accounted for 46.4% of total GHGs, with major sources from barley agriculture, malted barley transportation, and bottle production. Direct emissions (scope 1) accounted for only 14.9% of GHGs, while scope 2 emissions, comprised mainly of energy consumption, accounted for 38.7% of GHGs. The case study and interviews found that the main challenges in calculating brewery GHGs are secondary data availability, technical knowledge, and finances. The study also found that the main benefits for Ontario breweries to measure their GHGs include sustainability marketing and preserving the environment. The interviews also found a poor understanding of carbon regulation among Ontario Craft Brewers, which is interesting considering that Ontario implemented a provincial cap and trade program in 2017.
ARTICLE | doi:10.20944/preprints201808.0289.v1
Subject: Materials Science, Polymers & Plastics Keywords: Microinjection molding; Hybrid fillers; Multi-walled carbon nanotubes; Carbon black; Conductive polymer composites; Microstructure
Online: 16 August 2018 (14:25:56 CEST)
The effect of hybrid carbon fillers of multi-walled carbon nanotubes (CNT) and carbon black (CB) on the electrical and morphological properties of polystyrene (PS) nanocomposites were systematically investigated in microinjection molding (μIM). The polymer nanocomposites with three different filler concentrations (i.e. 3, 5 and 10 wt%) at various weight ratios of CNT/CB (100/0, 30/70, 50/50, 70/30, 0/100) were prepared by melt blending, then followed by μIM under a defined set of processing conditions. A rectangular mold insert which has three consecutive zones with decreasing thickness along the flow direction was adopted to study abrupt changes in mold geometry on the properties of resultant microparts. The distribution of carbon fillers within microparts was observed by scanning electron microscope, which was correlated with electrical conductivity measurements. Results indicated that there is a flow-induced orientation of incorporated carbon fillers and this orientation increased with increasing shearing effect along the flow direction. High structure CB is found to be more effective than CNT in terms of enhancing the electrical conductivity, which was attributed to the good dispersion of CB in PS and their ability to form conductive networks via self-assembly. Morphology observations indicated that there is a shear-induced depletion of CB particles in the shear layer, which is due to the marked difference of shear rates between the shear and core layers of the molded microparts. Moreover, an annealing treatment is beneficial to enhance the electrical conductivity of CNT-containing microparts.
ARTICLE | doi:10.20944/preprints202301.0152.v1
Subject: Earth Sciences, Environmental Sciences Keywords: riverine particulate material; phytoplankton; seawater; growth; organic carbon cycle; nutrients; primary production; carbon burial; CO2
Online: 9 January 2023 (07:52:27 CET)
Riverine particulates dominate the transport of vital nutrients like Si, Fe or P to the ocean mar-gins, where they may increase primary production by acting as slow release fertilizer. Further-more, the supply of particulate surface area to the ocean is considered to be a major control or-ganic carbon burial. Taken together, these observations suggest a close link between the supply of riverine particulate material and the organic carbon cycle. To explore this link, we conducted microcosm experiments to measure the growth of the marine diatom Thalassiosira weissflogii in the presence and absence of different types and concentrations of riverine particulate material. Results demonstrate a strong positive effect of riverine particulate material on diatom growth with increased total diatom concentrations and slowed post-exponential death rates with in-creasing particulate concentration. Moreover, SEM and optical microscope investigations con-firm that riverine particulates facilitates organic carbon burial through their role in the aggrega-tion and sedimentation of phytoplankton. The supply of riverine particulate material has been shown to be markedly climate sensitive with their fluxes increasing dramatically with increas-ing global temperature and runoff. This pronounced climate sensitivity implies that riverine particulates contribute substantially in regulating atmospheric CO2 concentrations through their role in the organic carbon cycle.
ARTICLE | doi:10.20944/preprints202206.0154.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Above ground biomass; allometric equation; forest conservation; climate change mitigation; Biomass; carbon dioxide; carbon Sequestration
Online: 10 June 2022 (08:15:38 CEST)
Forests play an important role in reducing greenhouse gases in the atmosphere, thereby mitigating the impact of climate change. Estimating the accumulated biomass in a forest ecosystem is important for assessing the productivity and sustainability of the forest. Allometric models for above ground biomass (AGB) are linear regression equations based on the relationships between biomass and diameter at breast height (DBH), tree height (H), and/or wood density. This study estimates AGB in the Colo-I-Suva Forest Park by applying the allometry of Chave et al (2005) and the diameter: height ratio derived from Payton & Weaver (2011) for height estimation in a plot of 20
ARTICLE | doi:10.20944/preprints202111.0483.v1
Subject: Materials Science, Nanotechnology Keywords: carbon nanotube; plastic; chemical recycling, life cycle assessment; Ethernet; circular economy; data transmission, carbon footprint
Online: 25 November 2021 (16:03:05 CET)
For every three people on the planet there is approximately two Tonne (Te) of available plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the co-addition to solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas in a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multi-walled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.3% to 14.2%. Since both the CNT diameters and the percentage yield increased with respect to polystyrene addition, we conclude that carbon from the PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid washed Bucky papers produced from each loading, ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, the materials with different loading were mixed to create six wires of an Ethernet cable and tested using iPerf to give uplink and downlink speeds of ~99.5 Mbps, comparable to Cu wire of identical dimension (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for the use case in a Boeing 747-400 over the lifespan of the craft. Due to their lightweight nature the CNT wires decreased the CO2 footprint by 21 kTonne (kTe) over the aircraft lifespan.
ARTICLE | doi:10.20944/preprints201810.0568.v1
Subject: Biology, Forestry Keywords: ecological chemometrics; carbon cycle; nitrogen cycle; carbon and nitrogen distribution; plant leaf-litter-soil continuum
Online: 24 October 2018 (11:12:48 CEST)
We analyzed the plant-litter-soil continuum to investigate the carbon and nitrogen distribution and ecological stoichiometry of an evergreen broad-leaved forest at Dagangshan Mountain, Jiangxi. The results showed that the average C and N contents and C:N ratios in the leaves and fine roots among 6 different tree species were 401.87g/kg, 21.41g/kg, 19.27 and 348.64g/kg, 15.73g/kg, 23.97, respectively; the average C and N contents and C:N ratios were 323.06 g/kg, 12.76 g/kg, 25.58 respectively in leaf litter, and 16.40 g/kg, 1.09 g/kg, 16.27 respectively for soil. In contrast with the C content, the total N content of the fine roots and litter had a high coefficient of variation and a high spatial heterogeneity. We ranked the six different representative tree species according to total C and N content in leaves and fine roots. The results for each species were generally consistent with each other, showing a positive correlation relationship between total C and N content in the leaves and roots. Among them, S. discolor (Champ. ex Benth.) Muell. plants displayed high carbon and nitrogen storage capacities, and on the other hand, C. fargesii Franch., C. myrsinifolia (Blume) Oersted, A. fortunei (Hemsl.) Makino, and V. fordii (Hemsl.) Airy Shaw showed a high nitrogen transfer rate. Total soil N and C decreased with depth. Soil organic carbon (SOC), soil resistant organic carbon (ROC), total N, alkali nitrogen, NH4+-N and NO3--N contents were all also negative correlated with soil depth, but the contents of the NH4+-N and NO3--N did not change significantly; The spatial distribution of soil NO3--N was significantly heterogeneous. At 0-10 cm soil depth, SOC was positively correlated with alkaline nitrogen, and at 10-20 cm soil depth, SOC was significantly positively correlated with total N. In general, when soil carbon was abundant, nitrogen supply capacity was also high.
ARTICLE | doi:10.20944/preprints201704.0095.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: twisted carbon nanotube (twisted CNT); stretched carbon nanotube (stretched CNT); magneto resistance (MR); spin efficiency
Online: 17 April 2017 (10:07:52 CEST)
Spin dependent quantum transport properties in twisted carbon nanotube and stretched carbon nanotube are calculated using density functional theory (DFT) and non-equilibrium green’s function (NEGF) formulation. Twisting and stretching have no effect on spin transport in CNTs at low bias voltages. However, at high bias voltages the effects are significant. Stretching restricts any spin-up current in antiparallel configuration (APC) which results in higher magneto resistance (MR). Twisting allows spin-up current almost equivalent to the pristine CNT case resulting in lower MR. High spin filtration is observed in PC and APC for pristine, stretched and twisted structures at all applied voltages. In APC, at low voltages spin filtration in stretched CNT is higher than in pristine and twisted ones with pristine giving higher spin filtration than twisted CNT.
ARTICLE | doi:10.20944/preprints202205.0241.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: carbon-footprint; dentistry; environment; management; sustainability
Online: 18 May 2022 (10:43:57 CEST)
Background There is increasing awareness of problems associated with global warming but a lack of a systematic approach on how to deliver more environmentally sustainable dental care. A sustainable world aims to ensure that basic needs and quality of life of everyone are met, now and for future generations. The carbon footprint is an indicator of environmental sustainability. Aim The aim is to suggest an environmental management change for the dental practice focusing on the objective of carbon footprint reduction. Environmental management change design The management change is based on the concept of “Plan-Do-Check-Act”, as recommended by the International Organisation for Standardisation (ISO) and described through the environmental aspects of the dental practice. The approach focuses on establishing and implementing environmental objectives, followed by monitoring results and taking actions to improve continually. The environmental aspects considered for the dental practice are activities causing an impact on the carbon footprint: energy use, travel, product purchasing, waste production, emission to air, water use, and contamination of land. Conclusions The “Plan-Do-Check-Act” ISO 14100-2015 model can be effectively integrated into the dental practice setting for its environmental management. A reduction of the carbon footprint of the dental practice is achieved by applying the environmental management change described for each activity.
ARTICLE | doi:10.20944/preprints202008.0673.v2
Subject: Materials Science, Nanotechnology Keywords: carbon nanotube; catalyst; alloy; nanoparticle; electrospray
Online: 17 September 2020 (12:01:44 CEST)
The direct growth of single-walled carbon nanotubes (SWCNTs) with a narrow distribution of diameter or chirality remains elusive despite significant benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT synthesis, but how to precisely manipulate their chemistry, size, concentration, and deposition remains difficult, especially within a continuous production process from the gas-phase. Here, we demonstrate the preparation of W6Co7 alloyed nanoparticle catalysts with precisely tunable stoichiometry using electrospray, which remain solid state during SWCNT growth. We also demonstrate continuous production of liquid iron nanoparticles with in-line size selection. With the precise size manipulation of catalysts in the range of 1-5 nm, and a nearly monodisperse distribution (σg < 1.2), an excellent size selection of SWCNT can be achieved. All of the presented techniques show great potential to facilitate the realization of single-chirality SWCNT production.
ARTICLE | doi:10.20944/preprints202009.0384.v1
Online: 17 September 2020 (07:50:55 CEST)
Researchers’ attention has been turned on Health expenditure, Carbon emissions, and economic growth as they play a focal role in the current debate on environmental protection and sustainable development. Our paper endeavors to investigate the impact of economic growth and CO2 emissions on Health expenditure for two main countries in Asia (China and India) using a dynamic panel data model estimated employing the Generalized Method of Moments (GMM) for the period 1960–2019. Our empirical results show that there is a significant relationship between health expenditure, CO2 emissions, and economic growth. The empirical evidence indicates a significant positive impact of CO2 emissions on health expenditure whiles economic growth has a negative impact on health expenditure for both countries for the period under study. The population growth rate has transposed effect on India's health spending; on the other hand, its impact on China’s health spending is significantly positive. The strong observable correlation between health expenditure and economic growth is crucial for economic development.
ARTICLE | doi:10.20944/preprints202008.0325.v1
Subject: Materials Science, Nanotechnology Keywords: Carbon; Crystal structure; Graphene; Graphite; Nanoplatelet.
Online: 14 August 2020 (11:58:53 CEST)
Graphite nanoplatelets (GNPs) were produced from flake graphite that had been immersed in isopropyl alcohol solution (70%) and converted to powder form in an ultrasonic bath (5 h, room temperature). Scanning and transmission electron microscopy, X-ray diffractometry, and Raman spectroscopy identified 120-nm-thick GNP crystallites and 0.5–21 µm plates with different areas and shapes. Extensive exfoliation was observed by transmission electron microscopy with abundant multilayer and some monolayer GNPs. X-ray diffractometry confirmed 43 GNP layers along the c-axis. Raman spectroscopy indicated well-defined GNPs with few defects and no oxide content. Rietveld analysis indicated a GNP crystal lattice with stacks of parallel two-dimensional graphene layers and tightly bound hybridized carbon atoms stacked in a translational …ABAB… sequence in hexagonal rings.
ARTICLE | doi:10.20944/preprints202005.0419.v1
Subject: Materials Science, Polymers & Plastics Keywords: polyacrylonitrile; stabilization; cyclization; kinetics; carbon fiber
Online: 26 May 2020 (05:30:13 CEST)
A methodology is proposed for designing the stabilization process of polyacrylonitrile (PAN) fibers. In its core, this methodology is based on a model that describes the characteristic fiber length change during the treatment, through the de-convolution of the three main contributors (i.e. entropic shrinkage, creep, and chemical shrinkage). The model has the additional advantage of offering further insight into the physical and chemical phenomena taking place during the treatment. Validation of PAN-model prediction performance for different processing parameters was achieved as demonstrated by FTIR and DSC. Τensile testing revealed the effect of processing parameters on fiber quality, while model prediction demonstrated that ladder polymer formation is accelerated at temperatures over 200oC. Additionally, according the DSC and FTIR measurements predictions from the application of the model during stabilization seem to be more precise at high-temperature stabilization stages. It was shown that mechanical properties could be enhanced preferably by including a treatment step below 200oC, before the initiation of cyclization reactions. Further confirmation was provided via Raman spectroscopy, which demonstrated that graphitic like planes are formed upon stabilization above 200oC, and thus multistage stabilization is required to optimize synthesis of carbon fibers. Optical Microscopy proved that isothermal stabilization treatment did not severy alter the cross section geometry of PAN fiber monofilaments.
ARTICLE | doi:10.20944/preprints202005.0302.v1
Subject: Chemistry, Applied Chemistry Keywords: lanthanum; multiwalled carbon nanotubes; adsorption; recovery
Online: 18 May 2020 (12:35:28 CEST)
The behaviour of oxidized and non-oxidized multiwalled carbon nanotubes in the adsorption of lanthanum(III) from aqueous solutions is described. Metal uptake is studied as a function of several variables such as the stirring speed of the system, pH of the aqueous solution and metal and nanomaterial concentrations. The experimental results are fitted to various kinetics and isotherm models, being the rate law fitted to the film diffusion and particle diffusion models, when the non-oxidized and the oxidized nanomaterials are used to remove lanthanum from the solution, respectively. Sulphuric acid solutions seem to be appropriate to recover the metal from La-loaded nanomaterials.
ARTICLE | doi:10.20944/preprints202003.0023.v1
Subject: Earth Sciences, Environmental Sciences Keywords: shifting cultivation; Philippines; biodiversity; carbon; REDD+
Online: 2 March 2020 (02:27:00 CET)
The Philippines is both a biodiversity hotspot and a megadiverse country. The country also has experienced one of the highest rates of deforestation in Southeast Asia and is among the first countries to introduce a massive reforestation program to address the country’s rapid biodiversity and forest loss. Drawing upon an empirical study from the Leyte island and other relevant case studies from the Philippines, in this chapter, we demonstrate that recovering secondary forests following shifting cultivation, locally known as kaingin have the high potentials for biodiversity and carbon co-benefits. Based on our empirical study, we also found that secondary forest regrowing after kaingin use can potentially be used as a cost-effective reforestation measure with multiple benefits to people and the environment in upland areas of the Philippines. We also discuss measures that are essential for such programs to be successful.
ARTICLE | doi:10.20944/preprints201909.0185.v1
Subject: Materials Science, Metallurgy Keywords: activated carbon; adsorption; copper; winemaking wastes
Online: 17 September 2019 (11:44:45 CEST)
This article presents the copper ions adsorption process using an activated carbon from winemaking wastes. The pH, temperature, activated carbon amount and initial copper concentration were varied based on a full factorial 2k experimental design. Kinetic and thermodynamic studies were also carried out. The adsorption kinetics was found follow a pseudo-second-order model. The adsorption data fit better to the Langmuir isotherm. The ANOVA demonstrated that both pH of the solution and activated carbon dosage had the greatest influence on copper adsorption. The activation energy was -32 kJ·mol-1 suggesting that the copper adsorption is a physic-sorption process. The best fit to a linear correlation was the moving boundary equation that controls the kinetics for the adsorption copper ions onto the activated carbon. The X-ray photoelectron spectroscopy (XPS) results reveal the existence of different copper species (Cu2+, Cu+ and or Cu0) on the surface of the carbonaceous adsorbent after the adsorption, which could suggest a simultaneous reduction process.
ARTICLE | doi:10.20944/preprints201812.0328.v1
Online: 28 December 2018 (04:20:40 CET)
The harmful nature of high concentrations of antibiotics to humans and animals requires urgent development of novel materials and techniques for their absorption. In this work, CTAB (Cetyltrimethyl Ammonium Bromide)-assisted synthesis of ZIF-8 (zeolitic imidazolate framework) derived hollow carbon (ZHC) was designed, prepared and used as a high-performance adsorbent, further evaluated by Langmuir and Freundlich isothermal adsorption experiments, dynamic analysis as well as theoretical calculation. The maximum capacities of ZHC on adsorbing tetracycline (TC), norfloxacin (NFO) and levofloxacin (OFO) are 267.3, 125.6 and 227.8 mg g-1, respectively, which delivers superior adsorptive performance when compared to widely studied inorganic adsorbates. The design concept of ZIFs-derived hollow carbon material provides guidance and insights for the efficient adsorbent of environmental antibiotics.
ARTICLE | doi:10.20944/preprints201612.0133.v1
Subject: Materials Science, General Materials Science Keywords: MoS2; carbon nanofibers; electrospinning; anode material
Online: 28 December 2016 (10:49:33 CET)
The one-dimensional MoS2/carbon nanofibers (1D MoS2/CNFs) are synthesized by electrospinning using exfoliated MoS2 nanosheets and polyacrylonitrile as raw materials. The exfoliated MoS2 nanosheets with size of about 150 nm are encapsulated in carbon nanofibers, and the free-standing MoS2/CNFs can be easily cut into flexible tablet and directly used as binder-free anode for lithium storage. The resultant 1D MoS2/CNFs exhibit a very high reversible capacity of 700 mAh g-1 at 100 mA g-1 after 50 cycles, high rate capacity (450 mAh g-1 at 1000 mA g-1 after 200 cycles) and good cycle stability.
ARTICLE | doi:10.20944/preprints201806.0106.v1
Subject: Engineering, Energy & Fuel Technology Keywords: carbon dioxide; carbon monoxide; cetane improver; ethanol; high content of oxygen; ignition quality; waste plastic pyrolysis oil
Online: 7 June 2018 (08:32:07 CEST)
Alternative fuels available at low cost, friendly to natural environments and meet the energy needs and demands, have witnessed a growing demand and use today. Ethanol is an attractive renewable energy source with a high content of oxygen. Ethanol can be produced through ethanolisis, however for this work direct blending of conventional diesel, waste plastic pyrolysis oil and ethanol with commercial fuel improver CI-0808 purchased from Innospec company was attempted. The primary purpose of adding a cetane improver was to improve the combustion characteristics of the blends by at least 1- 3 ignition quality points. Five mixing ratios were chosen in the following order, 50:25:25, 60: 20:20, 70: 15:15, 80: 10:10 and 90: 5:5 for Waste Plastic Pyrolysis Oil (WPPO), ethanol and conventional diesel (CD) respectively. However, for the fuel additive mixing ratio the total volume percentage was considered and the ratio put at 0.01% of the total quantity of blended fuel. In this work WPPO, diesel blends and fuel additives improvers were used as alternative fuel. This was to evaluate their performance and emission characteristics in a stationary single cylinder water cooled experimental diesel engine. The CI-0808 was added due to its potential power to reduce emissions of CO, UHC, NOX, PM and improved engine performance. The results obtained were compared carefully to ASTM standards and discussed using graph curves figures and tabulated values. The conclusion was that ethanol and WPPO blends can be used in diesel engines as alternative fuel without modification. Used in combination with cetane improvers the emissions reduce significantly and performance improved equalling that of conventional diesel fuel.
ARTICLE | doi:10.20944/preprints202211.0527.v1
Subject: Materials Science, General Materials Science Keywords: Carbon nanowall; Molybdenum disulfide; Interlayer; Morphological characteristics
Online: 29 November 2022 (03:09:25 CET)
Carbon, which exists in large quantities on Earth, is a material with interesting properties, and many studies have been conducted since the past. In particular, nano-sized carbon allotropes are called carbon nanomaterials, and many studies are currently underway. Among them, carbon nanowall (CNW) is a structure in which graphene of sp2 bond is grown vertically, CNW have outstanding strength, can be highly electrically conducting or semiconducting, have a large specific surface area per unit mass. Electrical, chemical, physical properties of these CNW is modified by parameter such as surface density, height and thickness of it. Those have great effect on CNW and can be adjusted as growth interlayer. It was confirmed that the molybdenum disulfide (MoS2) interlayer synthesized by radio frequency (RF) magnetron sputtering altered the morphological characteristics such as the shaped edge of the CNW, the pores diameter and density. Through these studies, we confirmed the effect of MoS2 on the morphological characteristics of CNW. This opens the door to improving the performance of electrodes and devices.
ARTICLE | doi:10.20944/preprints202201.0109.v1
Subject: Materials Science, Nanotechnology Keywords: magnetization; photoluminescence; carbon dots; magnetic nanoparticles; antimicrobial
Online: 10 January 2022 (12:21:24 CET)
We present a simple strategy to generate a family of carbon dot/iron oxide nanoparticles (C/Fe-NPs) that relies on the thermal decomposition of iron (III) acetylacetonate in the presence of a highly fluorescent carbon-rich precursor, while polyethylene glycol serves as the passivation agent. By varying the molar ratio of the reactants, a series of C/Fe-NPs have been synthesized with tuneable elemental composition in terms of C, H, O, N, Fe. The quantum yield is enhanced from 6% to 9% as the carbon content increases from 27% to 36%, while the room temperature saturation magnetization is improved from 4.1 emu/g to 17.7 emu/g as the iron content is enriched from 17 to 31%. In addition, the C/Fe-NPs show excellent antimicrobial properties, minimal cytotoxicity and demonstrate promising bioimaging capabilities, thus showing great potential for the development of advanced diagnostic tools.
ARTICLE | doi:10.20944/preprints202110.0109.v1
Online: 6 October 2021 (15:20:34 CEST)
The current Global Climate Change, the 2030 Agenda and the Planetary boundaries have driven new development strategies, such as the circular economy, bioeconomy and biorefineries. In this framework, this study analyzes the potential availability and sustainability of the wood supply chain for a small-scale biorefinery aiming at producing 280–300 L of bioethanol per ton dry biomass, consuming 30,000 t of dry biomass per year harvested in a 50 km radius. This wood production goal was assessed from Eucalyptus grandis stands planted for solid wood in northeastern Uruguay. Moreover, to understand the environmental performance of this biomass supply chain, the energy return on investment (EROI), carbon footprint (CF) and potential soil erosion were also assessed. The results showed that the potential wood production would supply an average of 81,800 t of dry mass per year, maintaining the soil erosion below the upper threshold recommended, an EROI of 2.3 and annual CF of 1.22 kg CO2-eq m–3 (2.6 g CO2-eq MJ–1). Combined with the environmental performance of the bioethanol biorefinery facility, these results would show acceptable values of sustainability according to EU Directive 2009/28/ec because the bioethanol CF becomes 1.7% of this petrol’s CF.
ARTICLE | doi:10.20944/preprints202103.0550.v1
Subject: Materials Science, Biomaterials Keywords: biocompatibility; carbon nanomaterials; graphite; phototherapy; skin disease.
Online: 22 March 2021 (15:47:21 CET)
Nanostructured carriers have been widely used in pharmaceutical formulations for dermatological treatment. They offer targeted drug delivery, sustained release, improved biostability, and low toxicity, usually presenting advantages over conventional formulations. Due to its large surface area, small size and photothermal properties, graphene oxide (GO) has the potential to be used for such applications. Nanographene oxide (GOn) presented average sizes of 197.6 ± 11.8 nm, and a surface charge of -39.4 ± 1.8 mV, being stable in water for over 6 months. 55.5 % of the mass of GOn dispersion (at a concentration of 1 mg mL-1) permeated the skin after 6 h of exposure. GOn dispersions have been shown to absorb near-infrared radiation, reaching temperatures up to 45.7 °C, within mild photothermal therapy temperature range. Furthermore, GOn in amounts superior to those which could permeate the skin were shown not to affect human skin fibroblasts (HFF-1) morphology or viability, after 24 h of incubation. Due to its large size, no skin permeation was observed for graphite particles in aqueous dispersions stabilized with Pluronic P-123 (Gt-P-123). Altogether, for the first time, GOn potential as a topic administration agent and for delivery of photothermal therapy has been demonstrated.
ARTICLE | doi:10.20944/preprints202102.0036.v1
Subject: Earth Sciences, Atmospheric Science Keywords: alkalinity; carbon; coast; Wadden Sea; German Bight
Online: 1 February 2021 (13:52:55 CET)
High alkalinity values on the seaside can influence the exchange of carbon dioxide between seawater and the atmosphere. Still, there are many uncertainties about biogeochemical processes responsible for alkalinity generation in the coastal area. One example of coastal areas with high alkalinity is the German Bight. The German Bight is the south-east part of the North Sea. The literature suggests that high summer alkalinity values in the German Bight result from the exchange of the German Bight with the Wadden Sea (an intertidal zone along Dutch, German, and Danish coasts). We show that the origin of high alkalinity values in the German Bight can be sulfate reduction in sediments of the Wadden Sea and that it can increase alkalinity from March to August up to approximately 220 micromoles per liter. Also, we show that sulfate reduction does not cause any significant year alkalinity flux from the Wadden Sea to the German Bight; instead, nitrogen compounds ( and ) are responsible for it and cause an alkalinity flux about 13 GM a year from the Wadden Sea to the German Bight.
REVIEW | doi:10.20944/preprints202011.0547.v1
Subject: Materials Science, Biomaterials Keywords: Carbon dots; organic light-emitting diode; photoluminescence
Online: 20 November 2020 (14:48:50 CET)
In the last 10 years, carbon dots (CDs) synthesized from renewable organic resources have been gathered a considerable amount of attention in different fields for their peculiar photoluminescent properties. Moreover, the synthesis of CDs fully responds to the principles of the circular chemistry and the concept of safe-by-design. This review will focus on the different strategies for the incorporation of CDs in organic light-emitting devices (OLEDs) and on the study of the impact of CDs properties on the OLEDs performance. The main current research outcomes and highlights are summarized to guide users towards the fully exploitation of use these materials in optoelectronic applications.
ARTICLE | doi:10.20944/preprints202011.0004.v1
Subject: Materials Science, Nanotechnology Keywords: carbon fiber; wire-type; CoMn3O4; supercapacitor electrodes
Online: 2 November 2020 (09:08:34 CET)
In this work, we report the carbon fiber-based wire-type asymmetric supercapacitors (ASCs). The highly conductive carbon fibers were prepared by the carbonized and graphitized process using the polyimide (PI) as a carbon fiber precursor. To assemble the ASC device, the CoMnO2-coated and Fe2O3-coated carbon fibers were used as the cathode and the anode materials, respectively. FE-SEM analysis confirmed that the CoMnO2-coated carbon fiber electrode exhibited the porous hierarchical interconnected nanosheet structures, depending on the added amounts of ammonium persulfate (APS) as an oxidizing agent, and Fe2O3-coated carbon fiber electrode showed a uniform distribution of porous Fe2O3 nanorods over the surface of carbon fibers. The nanostructured CoMnO2 were directly deposited onto carbon fibers by a chemical oxidation route without high temperature treatments. In particular, the electrochemical properties of the CoMnO2-coated carbon fiber with the concentration of 6 mmol APS presented the enhanced electrochemical activity, probably due to its porous morphologies and good conductivity. Further, to reduce the interfacial contact resistance as well as improve the adhesion between transition metal nanostructures and carbon fibers, the carbon fibers were pre-coated with the Ni layer as a seed layer using an electrochemical deposition method. The fabricated ASC device delivered a specific capacitance of 221 F g-1 at 0.7 A g-1 and good rate capability of 34.8% at 4.9 A g-1. Moreover, the wire-type device displayed the superior energy density of 60.16 Wh kg-1 at a power density of 490 W kg-1 and excellent capacitance retention of 95% up to 3,000 charge/discharge cycles.
ARTICLE | doi:10.20944/preprints202009.0761.v1
Subject: Earth Sciences, Atmospheric Science Keywords: black carbon; snow; albedo; glaciers; trajectories, Vallunaraju
Online: 30 September 2020 (17:53:58 CEST)
The role of Black Carbon (BC) as a contributor to glacial retreat is of particular interest to the scientific community and decision makers, due to its impact on snow albedo and glacier melt. In this study, a thermal-optical instrument (LAHM) was used to measure effective Black Carbon (eBC) in a series of surface snow samples collected from the Vallunaraju glacier, Cordillera Blanca, between April 2019 and May 2020. The time series obtained indicates a marked seasonal variability of eBC with maximum concentrations during the dry season and dramatic decrease during the wet season. The concentrations detected ranged between a minimum of 3.73 ng/g and 4.23 ng/g during the wet season and a maximum of 214.13 ng/g and 181.60 ng/g during the dry season, in the accumulation and ablation zone. Using SNICAR model, the reduction of albedo was estimated at 6.36% and 6.60% during the dry season and 0.68% and 0.95% during the wet season, which represents an average radiative forcing of 4.52 ± 1.84 W/m2 and 4.69 ± 1.59 W/m2 in the accumulation zone, and 0.49 ± 0.27 W/m2 and 0.68 ± 0.43 W/m2 in the ablation zone. The melting of snow due to the eBC translates into 80.18 ± 37.30 kg/m2 and 83.16 ± 32.75 kg/m2 during the dry season, and 7.91 ± 4.29 kg/m2 and 10.85 ± 6.62 kg/m2 during the wet season, in the accumulation and ablation zones, respectively. Finally, the HYSPLIT trajectory assessment shows that aerosols predominate in the Amazon rainforest, especially when forest fires are most abundant according to VIIRS images.
ARTICLE | doi:10.20944/preprints202009.0336.v1
Subject: Materials Science, Polymers & Plastics Keywords: Thermal conductivity; Electrical conductivity; Composite; Carbon fiber
Online: 15 September 2020 (09:00:04 CEST)
The electrical, mechanical and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. EBC/carbon-fiber composites can be utilized as an electro-mechanical material which is capable of changing it electric resistance with mechanical strain. Carbon fibers were introduced to EBC with different concentrations (5-25 wt%). The results showed that the addition of carbon fibers to EBC could increase the electric resistance up to 10 times. Increasing the load to 2.9 MPa could increase the electric resistance change by 4500% compared 25% fiber sample with pure EBC. It is also noted that the electric resistance of the EBC/CF composites underwent a dramatic increase with raising the strain, for example, the resistance change was around 13 times more at 15% strain in comparison to 5% of strain; The thermal conductivity tests showed that the addition of carbon fibers could increase the thermal conductivity by 40%, from 0.19 to 0.27 (Wm-1K-1). It was also observed that the addition of carbon fibers to EBC could increase the thermal conductivity.
Subject: Earth Sciences, Atmospheric Science Keywords: temperature precursors; carbon dioxide; HadCRUT4; Mauna Loa
Online: 26 June 2020 (12:30:25 CEST)
The non-secular anomalies in carbon dioxide measurements at Mauna Loa are compared to the non-secular anomalies in the HadCRUT4 median global temperature from 1991 to 2020. A strong and significant Pearson's product-moment correlation is found between carbon dioxide anomalies and global temperature anomaly, indicating that the correlation is an actual characteristic of the atmosphere. But more important from a numerical weather prediction perspective, this result indicates that carbon dioxide anomalies can have no skills as temperature precursors on short time scales.
ARTICLE | doi:10.20944/preprints202001.0254.v1
Subject: Materials Science, Metallurgy Keywords: adsorption; Lanthanum; Cerium; carbon nanotubes; rare earth
Online: 22 January 2020 (03:21:11 CET)
Since the 1960s Rare earths (REs) applications gradually have expanded to everyday life. REs have great strategic importance in industrial and technological development, so it is expected an increase in their demand. Among the REs the European Commission considered Cerium and Lanthanum as critical raw materials. This research article studies the adsorption of Ce and La onto two carbon nanomaterials, multiwalled carbon nanotubes (MWCNT) and carboxylic functionalized multiwalled carbon nanotubes (MWCNT_ox). The latter has slightly more affinity for REs than MWCNT. The recovery percentage for Ce were 89 and 98% and in the case of for La were 99 and 92% using 0.8 g of MWCNT and 0.2 g of MWCNT_ox respectively. The adsorption process fits a pseudo second-order kinetic model and the Langmuir isotherm best represented the metal uptake.
ARTICLE | doi:10.20944/preprints201905.0045.v2
Subject: Engineering, Energy & Fuel Technology Keywords: fuel cell; carbon nanotube; catalyst; platinum-ruthenium
Online: 29 December 2019 (07:06:08 CET)
Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalysts in methanol fuel cells leads to increasing the cost of this kind of fuel cell which is considered as a barrier to the commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of electro-catalyst in the oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that the oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. The current density of methanol oxidation reaction increased up to 62% in CNT sample compared to CB supported one, therefore the active electrochemical surface area of the catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst. Moreover, the resistance of the CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of the CNT electro-catalyst show remarkable improvement compared to CB electro-catalyst in the long term.
ARTICLE | doi:10.20944/preprints201908.0076.v1
Subject: Chemistry, Applied Chemistry Keywords: dysprosium; activated carbon; spent coffee ground; adsorption
Online: 6 August 2019 (12:23:23 CEST)
This paper describes the physico-chemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m2·g-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g-1 and 33.52 mg·g-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.