Subject: Materials Science, Biomaterials Keywords: Silver nano dots; DNA; Biobar code assays; nano sensors; nano medicine
Online: 27 January 2021 (11:44:48 CET)
Nano medicine seeks to deliver a valuable set of research tools and clinically useful devices in the near future. The current medical field is in dire need of new commercial applications in the pharmaceutical industry that may include advanced drug delivery systems, new therapies, and in vivo imaging. Here in this experimental study, the nano materials used in DNA biosensors like silver nano dots were incorporated as nano biosensors are used for both therapeutic and diagnostic applications. The most important step while preparing a DNA biosensor is the immobilization of DNA probe on the surface of a sensing device such as an electrode. The amount of immobilized DNA probe will influence the accuracy sensitivity, selectivity and life of a DNA biosensor directly. Because of the high surface to volume ratio and excellent biological compatibility, nano materials can enlarge the sensing surface area to increase the amount of immobilized DNA and the DNA mixed with nano materials can keep its biologically activity well.In this study,silver nano dots created in our lab were functionalized with thio nucleides and were used as nano sensor probes in bio bar code assays.
ARTICLE | doi:10.20944/preprints201905.0298.v1
Subject: Chemistry, Chemical Engineering Keywords: silver nanoparticles; nano-TiO2; nano- ZnO; nanohybrids; antibacterial
Online: 24 May 2019 (12:44:36 CEST)
This work emphasizes to use silver decorative method to enhance the antibacterial activity of TiO2 and ZnO nanoparticles. These silver decorated nanoparticles (hybrid nanoparticles) were synthesized by using sodium borohydride as a reducing agent, with the weight ratio of Ag precursors: oxide nanoparticles = 1: 30. The morphology and optical property of these hybrid nanoparticles were investigated using transmission electron microscopy (TEM) and UV–vis spectroscopy. The agar-well diffusion method was used to evaluate their antibacterial activity against both Staphylococcus aureus and Escherichia coli bacteria, with or without light irradiation. The TEM images indicated clearly that silver nanoparticles (AgNPs, 5-10 nm) were well deposited on the surface of nano-TiO2 particles (30-60 nm). Besides, smaller AgNPs (< 2 nm) were dispersed on the surface of nano-ZnO particles (20-50 nm). UV-vis spectra confirmed that the hybridization of Ag and oxide nanoparticles led to shift the absorption edge of oxide nanoparticles to the lower energy region (visible region). The antibacterial tests indicated that both oxide pure nanoparticles did not exhibit inhibitory against bacteria, with or without light irradiation. However, the presence of AgNPs in their hybrids, even at low content (< 40 mg/mL) leads to a good antibacterial activity and the higher inhibition zones under light irradiation as compared to that in dark was observed.
ARTICLE | doi:10.20944/preprints201809.0359.v1
Subject: Materials Science, Nanotechnology Keywords: synchrotron X-ray diffraction; nano-structures; nano mechanics
Online: 18 September 2018 (16:50:04 CEST)
The three-point bending behavior of a single Au nanowire deformed with an atomic force microscope was monitored by coherent X-ray diffraction using a sub-micrometer sized hard X-ray beam. While three-dimensional reciprocal-space maps were recorded before and after deformation by standard rocking curves, they were measured by scanning the energy of the incident X-ray beam during deformation at different loading stages. The mechanical behavior of the nanowire is visualized in reciprocal space and a complex deformation mechanism is described. In addition to the expected bending of the nanowire, torsion is detected. Bending and torsion angles are quantified from the high resolution diffraction data.
ARTICLE | doi:10.20944/preprints202212.0514.v1
Subject: Materials Science, Nanotechnology Keywords: nano-alloy; Si-Cr; Si nano-needles; sub-100 nm; nanoscale
Online: 27 December 2022 (08:41:50 CET)
Ultra-short 230 fs laser pulses of 515 nm wavelength were tightly focused into 700 nm focal spots and utilised in opening ~ 400 nm nano-holes in a Cr etch mask that was tens-of-nm thick. Nano-holes ablated at slightly above the threshold of ablation irradiance became nano-disks and nano-rings at slightly lower pulse energies. Subtle sub-1 nJ pulse energy control was harnessed to pattern large surface areas with controlled nano-alloying of Si and Cr. This technique is extendable to vacuum-free large area patterning of nanolayers by alloying them at distinct locations with sub-diffraction resolution. Such metal masks with nano-hole opening can be used for formation of random patterns of nano-needles with sub-100 nm separation when applied to dry etching of Si.
REVIEW | doi:10.20944/preprints202104.0711.v1
Online: 27 April 2021 (12:31:25 CEST)
Electro-spun ultra-fine fibers exhibit two significant properties: a high surface-to-volume ratio and a relatively defect-free molecular structure. Due to the high surface-to-volume ratio, electro-spun materials are well suited for activities requiring increased physical contact, such as providing a site for a chemical reaction or filtration of small-sized physical materials. However, electrospinning has many shortcomings, including difficulties in producing inorganic nanofibers and a limited number or variety of polymers used in the process. The fabrication of nanofiber bundles via electrospinning is explored in this analytical study, as well as the relationship between extrinsic electrospinning parameters and the relative abundance of various fiber morphologies. Numerous variables could impact the fabrication of nanofibers, resulting in a variety of morphologies; therefore, adequate ambient conditions and selecting the appropriate solvent for achieving a homogenous polymer solution and uniform electro-spun materials are examined. Finally, common polymers suitable for electrospinning and the promising applications of ultra-fine fibers achieved via electrospinning are studied in this paper.
Online: 28 June 2019 (07:53:35 CEST)
The research progress of nano-hydroxyapatite and its composite biomaterials, which are widely used, is summarized. The preparation techniques and applications of nano-hydroxyapatite and its composites in tissue engineering scaffolds, sustained and controlled release drug carriers, targeting drug delivery and environmental functional materials show that nano-hydroxyapatite and its composites will have good prospects in the field of biomedicine. The nano-hydroxyapatite composite biomaterial is a first phase or multi-phase material added to the nano-hydroxyapatite to obtain a favorable histological reaction, satisfactory strength and rigidity, and to synthesize a scaffold material for tissue regeneration. As a scaffold for guiding bone tissue regeneration, nano-hydroxyapatite composite material can also be used as a targeted drug release system for drug delivery system. It has good biocompatibility and degradability and has become a research hotspot in bone tissue engineering. The complex is expected to be applied to medical diagnostic fields such as tumor cell detection and nano biological probes.
ARTICLE | doi:10.20944/preprints202112.0418.v1
Subject: Physical Sciences, General & Theoretical Physics Keywords: Relativity; Nano Technology; Magnetic materials
Online: 27 December 2021 (09:59:50 CET)
In a recent paper discussing Newton’s third law in the framework of special relativity for charged bodies, it was suggested that one can construct a practical relativistic motor provided high enough charge and current densities are available. As on the macroscopic scale charge density is limited by the phenomena of dielectric breakdown, it was suggested to take advantage of the high charge densities which are available on the microscopic scale. A preliminary analysis of this option denoted "nano relativistic scale" is studied in the current paper.
ARTICLE | doi:10.20944/preprints202212.0333.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Nanotechnology; Plant Nutrition; Nano Urea; Potato
Online: 19 December 2022 (09:14:27 CET)
In today’s world, it is the need of the hour to adopt new technology to sustain the production of the future. Nanotechnology is gaining popularity for its efficiency in various applied fields of science. In agriculture, nanomaterials have a huge impact on the efficiency of fertilizers pesticides, etc. As it requires very fewer quantities and has a negligible residual effect the environment is safe with the innovation of Nano fertilizer. Keeping this view into account an experimental Trial at a farmer’s field was carried out at Berui village in the Hooghly District of West Bengal during the winter (rabi) season of 2019 – 20 under the supervision of Berui Cooperative, KVK-Hooghly, BCKV, and IFFCO with nano-Urea, nano-Zn and nano-Cu using RBD design with 10 treatments and 3 replications. Experimental results revealed that the highest tuber yield was obtained in T-7 (50% N+100% P & K+ 2 spray of nano-Urea), and that was followed by T-10 (50% N + 100% P & K + 50% Zn + 1 spray each of Nano-Urea, Zn and Cu) and T-8 (100% N-P-K + 50% Zn + 2 spray of Nano-Zn). The performance of nano fertilizers, Nano- Urea, was quite promising and economically viable as compared to the 100% recommended dose with commercial fertilizers (RDF).
REVIEW | doi:10.20944/preprints202211.0186.v2
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Sleep deprivation; Cytokines; curcumin; nano – curcumin
Online: 11 November 2022 (02:06:44 CET)
In this review, the following information describes the manifestation of sleep deprivation by human beings and its adverse effect on their health. Sleep deprivation has been demonstrated into namely two types known as REM sleep and NREM sleep affecting our health in so a problematic way that it is making our body immune to many diseases leading to lethal problems. Therefore, great research by many scientists has discovered that the turmeric “Curcuma longa” which is been used in every Indian kitchen since ancient times, has shown a remarkable effect on the problem caused by sleep deprivation but due to its poor solubility and low bioavailability drawn it into a great disadvantage. But the help of the study of nanotechnology and the evolution of curcumin into nano–curcumin made the possibility of the remarkable effect by making the curcumin more potent and enhancing its stability. Immunological changes due to sleep deprivation lead to Alzheimer’s disease, glioma, neuropathic pains, and many more. Therefore, this review has been summarized as it is been providing information related to curcumin and its affection for sleep deprivation.
BRIEF REPORT | doi:10.20944/preprints202210.0253.v1
Subject: Engineering, Mechanical Engineering Keywords: rubber composites; Nano composite; laser vulcanization
Online: 18 October 2022 (07:08:58 CEST)
Rubber-based composites are widely used especially in transportation. The goal of this paper is to study the mechanical properties of rubber-based composites of carbon black and Nano Aluminum trioxide additive (50 nm). Various percentage of carbon black was used (20,40, and 60 phr). The increase in Carbon black percentage shows an increase in mechanical properties of the composites (for 60 phr properties tensile test improve by 49%, for hardness resistance the improve was 21%, and for the wear test the composite improve by 22%). Various wetting percentage of nano Aluminum trioxide was used (1,1.5,2, and 2.5 %). Increasing the wetting percentage increase tensile strength (27%, hardness resistance increase by 28%, and wear resistance increase nonlinearly with a percentage reaching 70%). Selecting the optimal composition of the two fillers, then study different irradiances for it with the ultraviolet laser of moderately low energy after the vulcanization process. Post ultraviolet laser of (345 nm). Furthermore, laser vulcanization shows improvement in mechanical properties.
ARTICLE | doi:10.20944/preprints202007.0394.v1
Subject: Materials Science, Polymers & Plastics Keywords: thermal properties; temperature diffusivity; nano cellulose
Online: 17 July 2020 (15:36:15 CEST)
The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of cellulose nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2%wt. of nanocellulose were synthesised by a simple chemical process. Films of a high optical transmittance T ≈ 80 % (for a 200- μ m-thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on: 1) a resistance change and 2) micro-thermocouple detected modulation of a heat wave, were used for the polymer films with cross-sections of ∼ 100 μ m thickness. Twice different in-plane α ‖ and out-of-plane α ⊥ temperature diffusivities were directly determined with high fidelity: α ‖ = 2 . 12 × 10 − 7 m 2 /s and α ⊥ = 1 . 13 × 10 − 7 m 2 /s. An amorphous polyethylene terephthalate (PET) fiber was measured for comparison α ‖ = 1 . 15 × 10 − 7 m 2 /s. This work provides an example of a direct contact measurement of thermal properties of nanocellulose composite films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this composite.
ARTICLE | doi:10.20944/preprints201807.0140.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: nano resonator; electromechanical system array; bolometer
Online: 9 July 2018 (13:20:01 CEST)
Microbolometer is the most common uncooled infrared technique that allows to achieve 50mK-temperature resolution on the scene. However, this approach has to struggle with both the self-heating inherent to the resistive readout principle and the 1/f noise. We present an alternative approach that consists in using micro / nanoresonators vibrating according to a torsional mode, and whose resonant frequency changes with the incident IR-radiation. Dense arrays of such electromechanical structures were fabricated with a 12µm-pitch at low temperature allowing their integration on CMOS circuits according to a post-processing method. H-shape pixels with 9 µm-long nano-rods and a cross-section of 250 × 30 nm² were fabricated to provide large thermal responses, whose experimental measurements reached up to 1024 Hz/nW. These electromechanical resonators featured a noise equivalent power of 140pW for a response time of less than 1 ms. To our knowledge, these performance are unrivaled with such small dimensions. We also showed that a temperature sensitivity of 20 mK within 100ms-integration time is conceivable at a 12µm-pitch by co-integrating the resonators with their readout electronics and suggesting a new readout scheme. This sensitivity could be reached at short-term by depositing on top of the nano-rods a vanadium oxide layer having a phase-transition that could possibly enhance the thermal response by one order of magnitude.
ARTICLE | doi:10.20944/preprints201801.0164.v1
Online: 18 January 2018 (04:31:20 CET)
The BRightest Target Explorer (BRITE) is the pioneering nanosatellite mission dedicated for photometric observations of the brightest stars in the sky. The BRITE CCD sensors are poorly shielded against extensive flux of energetic particles which constantly induce defects in the silicon lattice. In this paper we investigate the temporal evolution of the generation of the dark current in the BRITE CCDs over almost 4 years after launch. Utilizing several steps of image processing and employing normalization of the results it was possible to obtain useful information about the progress of thermal activity in the sensors. The outcomes show clear and consistent linear increase of induced damage despite the fact that only about 0.14% of CCD pixels were probed. By performing the analysis of temperature dependencies of the dark current, we identified the observed defects as phosphorus-vacancy (PV) pairs, which are common in proton irradiated CCD matrices. Moreover, the Meyer-Neldel empirical rule was confirmed in our dark current data, yielding EMN=24.8 meV for proton-induced PV defects.
ARTICLE | doi:10.20944/preprints201704.0028.v1
Subject: Materials Science, Nanotechnology Keywords: lanthanides; fluorapatite; drug loading; nano carrier
Online: 5 April 2017 (11:26:48 CEST)
Europium (Eu)-doped fluorapatite (FA) nanorods has a similar biocompatibility with hydroxyapatite (HA) in terms, attracted much attention as cell imaging biomaterials due to their luminescent property. Here, we will discuss the new feature of europium doped fluorapatite (Eu-FA) nanorods as anticancer drug carrier. Eu-FA nanorods was prepared using a hydrothermal method. The morphology, crystal structure, fluorescence and composition are investigated. The specific crystal structure, enabling an effective loading of drug molecules. Doxorubicin (DOX), used as an anticancer model drug, was shown to be effectively loaded onto the surface of the nanorods. The DOX release was fairly pH-dependent, occurring more rapidly at pH 5.5 than pH 7.4 was observed. The intracellular penetration of the DOX-loaded Eu-FA nanorods (Eu-FA/DOX) can be imaged in situ due to the self-fluorescence property. Treatment of melanoma A375 cells with Eu-FA/DOX elicited a more effective apoptosis rate than direct DOX treatment. Overall, Eu-FA show great promise for tracking and treating tumor, may potentially useful as a multifunctional carrier system to effectively load and sustainably deliver drugs.
ARTICLE | doi:10.20944/preprints202109.0311.v1
Subject: Chemistry, Organic Chemistry Keywords: Quinazolinone; Styrene; Methacrylate; Nano-silver; Antibacterial; Antitumor.
Online: 17 September 2021 (12:11:48 CEST)
Reaction of 2-mercapto-3-phenylquinazolin-4(3H)-one (MPQ) with both 4-vinyl benzyl chloride and allyl bromide furnished the reactive heterocyclic monomers 3-phenyl-2-((4-vinylbenzyl) thio) quinazolin-4(3H)-one (PVTQ) and 2-(allylthio)-3-phenylquinazolin-4(3H)-one (APQ), respectively. Copolymerization of PVTQ monomer with styrene and methyl methacrylate in the presence of 2,2′-azobisisobutyronitrile (AIBN) afforded the copolymers PS-co-PPVTQ and PMMA-co-PPVTQ, respectively. Similarly, copolymerization of monomer APQ with styrene and methyl methacrylate (MMA) afforded the copolymers PS-co-PAPQ and PMMA-co-PAPQ, respectively. The resulted copolymers were characterized by using FT-IR, 1H-NMR and GPC techniques. Silver nanocomposites of PS, PMMA, PS-co-PPVTQ, PMMA-co-PPVTQ, PS-co-PAPQ and PMMA-co-PAPQ were synthesized by the addition of silver nitrate into the polymer solution. The reduction of silver ions into silver nanoparticles was performed in DMF and water. Thermogravimetric (TGA) analysis was used to determine the thermal stability of the copolymers and their silver nanocomposites. The X-ray diffraction (XRD) analysis indicated the amorphous structures of the co-polymers and confirmed the formation of silver nanoparticles. The antitumor and antibacterial activities were screened for the copolymers and enhanced by the formation of their silver nanocomposites. In vivo antitumor activity in Ehrlich Ascitic Carcinoma (EAC) mice model showed that PS-co-PPVTQ/Ag NPs, PMMA-co-PPVTQ/Ag NPs, and PMMA-co-PAPQ/Ag NPs displayed promising inhibitory effects against EAC and induce apoptosis against MCF-7 cells.
REVIEW | doi:10.20944/preprints202106.0619.v1
Subject: Life Sciences, Biochemistry Keywords: Natural products; Madagascan active principles; Nano-delivery.
Online: 25 June 2021 (12:02:28 CEST)
Natural products endowed of biological activity represent a primary source of commodities ranging from nutrition to therapeutic agents, as well as cosmetic tools, and recreational principles. These natural means have been used by mankind since centuries if not millennia. They are commonly used all over the world and socio-economical contexts but are particularly attractive in disadvantaged area or economically emerging situations all over the world. This is very likely due to the relatively easy recovery of these bioactive principles from the environment, to the low if any cost as well as ease of administration and to the general popular compliance concerning their consumption/ingestion. In this concise review, we focus on some popular bioactive principles of botanical origin which find a wide use in the Madagascan populations. But, due to space limitations only some most common and largely diffused principles in this country are considered. Finally, a possible nanotechnological administration is discussed in the case where a potential therapeutic usage is envisaged.
Subject: Materials Science, Biomaterials Keywords: synthetic; xenogenous; nano-hydroxyapatita; beta-tricalcium phosphate
Online: 6 October 2020 (13:18:42 CEST)
Nowadays, we can observe a worldwide trend towards the development of synthetic biomaterials. Numerous researches have been carried out in order to better understand the cellular behavior involved in the inflammation and bone healing processes related to living tissues. The aim of this study is to evaluate the tissue behavior of two different types of biomaterials: synthetic nano-hydroxyapatite / beta-tricalcium phosphate and hydroxyapatite in non-critical bone defects in rat calvaria. Twenty four rats underwent surgery in which two 3 mm defects in each cavity were performed. The rats were divided into 2 groups: Group 1, using xenogen hydroxyapatite (Bio oss ™); Group 2, using synthetic nano-hydroxyapatite / beta-tricalcium phosphate (Blue Bone ™). Sixty days after the surgery, the calvaria bone defect was filled with biomaterial, the animals were sacrificed and marked with Masson's trichrome and PAS staining, and immunohistochemistry (TNF-α, MMP-9) and electron microscopy analyzes were performed. Histomorphometric analysis indicates a greater presence in the protein matrix in Group 2, in addition to higher levels of TNF-α, MMP-9. The ultrastructural analysis shows an association of material with fibroblasts in the tissue regeneration stage. Paired statistical data indicates that Blue Bone ™ can improve bone formation / remodeling when compared to biomaterials of xenogenous origin.
ARTICLE | doi:10.20944/preprints201901.0076.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: agitator; dirt; humidity; nano mill; temperature; time
Online: 8 January 2019 (15:34:45 CET)
A highly dirt resistant paint for building facades without chemicals harmful to nature and environment, is developed which resolves the unattractive disfigurement of building walls caused by dirt. The experimentation is scientifically and statistically planned with the aid of computer programming. It consists of a sequence of phases which include the selection of appropriate raw materials, adopting of Basic Language computer programming to generate a target population of paint formulations. The average PVC percentage is computed using theory and found to be 54.98% for the target population of 543143 paint formulations hence verifies the literature results. Experimentation and statistical analysis are performed to compare the classical conventional agitator with latest lab equipment like Nano mill and it is concluded that Nano mill performs better on the average than conventional agitator in preparation of paint formulations. Hence the sample of paint formulations is prepared on Nano mill and tested in laboratory using advanced available technology for the analysis and comparison of paint properties to determine the best paint formulation. The results are analyzed using Analysis Of Variance Technique (ANOVA) and it is concluded that the paint formulation named “O3” has the highest dirt resistance on the average. The final selected formula O3 is compared with three other competitor paints in market under natural environment for a period of almost one year. A regression model is also constructed to study the effect of environmental factors like time, temperature and humidity on dirt resistance of paints. It is found that O3 formulation is the best environment friendly which performs equally well with one competitor paint and has higher dirt resistance than two other competitor paint formulations containing harmful chemicals. The regression model of dirt resistance on variables including time, temperature and humidity shows that these factors are significantly affecting the dirt resistance of a given paint at 5% level of significance. 95.34% variation in the dirt resistance of a given paint is due to and explained by the given factors. The regression model is useful to predict the average dirt resistance of a given paint with a certain level of confidence. The project exemplifies the work of an applied research from conceptualization to successful commercialization for the paint industry.
ARTICLE | doi:10.20944/preprints201811.0121.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Nano-Magnetic; TiO2; Fe3O4; Degradation; 2,4-Dicholorophenol
Online: 5 November 2018 (14:45:11 CET)
In this work, pure TiO2 and nano-magnetic of Fe3O4/TiO2 were synthesized for degradation of 2,4-dichlorophenol (2, 4-DCP) as an organic pollutant. A range of analytical techniques including XRD, DRS, FESEM, and VSM were employed to reveal the crystal structure, morphology and property of the nanocomposite. The XRD results showed the prepared samples including 100% anatase phase. We obtained the band gap energy 2.9 and 2.8 eV for pure TiO2 and Fe3O4/TiO2 respectively. VSM results demonstrate that easy, fast separation and redispersion of Fe3O4/TiO2 sample can be realized. We obtained 62% and 31% degradation of 2,4-DCP in the presence of Fe3O4/TiO2 and pure TiO2 under visible light respectively.
ARTICLE | doi:10.20944/preprints201708.0005.v1
Subject: Engineering, Mechanical Engineering Keywords: piezoelectric; actuator; nano-positioning; flexure hinge; FEM
Online: 3 August 2017 (05:50:16 CEST)
A compact 2-DOF (two degrees of freedom) piezoelectric-driven platform for 3D cellular bio-assembly systems has been proposed based on “Z-shaped” flexure hinges. Multiple linear motions with high resolution both in x and y directions are achieved. The “Z-shaped” flexure hinges and the parallel-six-connecting-rods structure are utilized to obtain the lowest working stress while compared with other types of flexure hinges. In order to achieve the optimized structure, matrix-based compliance modeling (MCM) method and finite element method (FEM) are used to evaluate both the static and dynamic performances of the proposed 2-DOF piezoelectric-driven platform. Experimental results indicate that the maximum motion displacements for x stage and y stage are lx=17.65 μm and ly=15.45 μm, respectively. The step response time for x stage and y stage are tx=1.7 ms and ty =1.6 ms, respectively.
CONCEPT PAPER | doi:10.20944/preprints201612.0111.v2
Subject: Materials Science, Surfaces, Coatings & Films Keywords: chemical phosphate coating; EIS; nano TiO2; TAFEL
Online: 23 December 2016 (10:23:24 CET)
The present study aims at deposition of zinc phosphate coatings with the incorporation of nano Titanium dioxide particles by chemical phosphating method. Zinc phosphate coatings were developed on low carbon steel by using nano TiO2 in the standard phosphating bath. The Coated low carbon steel samples were assessed for corrosion studies using electrochemical impedance spectroscopy and potentiodynamic polarisation techniques in 3.5% NaCl solution. Chemical composition of the coatings was analysed by energy dispersive X-ray spectroscopy (EDX). Significant variations in the coating weight, porosity and corrosion resistance were observed with the addition of nano TiO2 in the phosphating bath. Corrosion rate of nano TiO2 incorporated chemical phosphate coated samples was found to be 3.5 mpy which was 4 times less than the bare uncoated low carbon steel (~14 mpy). Electrochemical impedance spectroscopy studies revels in the reduction of porosity in nano TiO2 phosphate coated samples. It was found that nano TiO2 particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal phosphating bath).
ARTICLE | doi:10.20944/preprints201811.0549.v1
Subject: Engineering, Automotive Engineering Keywords: Nano-Tribology, Nano-Lubricants, Al2O3 and TiO2 Nanomaterials, Tribological Behavior of Piston Ring Assembly, Gasoline Engine Performance, Fuel Economy
Online: 22 November 2018 (14:34:45 CET)
One of the most important objectives of the studies worldwide is to improve the performance of automotive engines to reduce fuel consumption and environmental pollution. Accordingly, the principal motivation of this research study is improving the tribological behavior of the piston ring/cylinder liner interfaces as a promising and straightforward approach in automotive fuel economy and increasing engine durability using Al2O3 and TiO2 nanomaterials as smart nano-lubricant additives that adapted to different operating conditions by replenishing mechanisms anti-friction and anti-wear in automotive engines.
ARTICLE | doi:10.20944/preprints202210.0121.v1
Subject: Engineering, Civil Engineering Keywords: nano-silica; C320 bitumen; rutting; penetration; DSR; MSCR
Online: 10 October 2022 (10:20:33 CEST)
Nanomaterials exhibit novel properties and profound attributes as an additive in asphalt binder modification. However, the application of nano-silica in asphalt binders and mixture modification is still limited and further research is required. Along these lines, in this work, nano-silica with a content from 2% to 8% and an increment of 2% were utilized in modifying the bitumen binder type C320, which is considered the most conventional type of bitumen used in Western Australia road asphalt mixtures. Various tests were performed to assess their properties including dynamic shear rheometer, penetration, softening point, and multiple stress creep recovery (MSCR) test. The extracted results revealed an increase in the strength and stiffness properties by lowering the penetration, improving the softening point, and increasing the complex shear modulus of all nano-silica modified bitumen samples. Interestingly, a relatively big content of nano-silica leads to a higher rutting resistance. Nevertheless, the rutting resistance was affected by the size of the nano-silica coated with the silane coupling agent. The ideal sample of nano-silica modified C320 was determined as NS-15nm (NS-A), which can improve the rutting resistance. Nevertheless, the rutting resistance of the modified asphalt mixtures needs to be further investigated in the future to elaborate on the impact of nano-silica as modified binders on the mechanical properties of Australian asphalt mixtures.
ARTICLE | doi:10.20944/preprints202203.0184.v3
Online: 4 April 2022 (11:57:37 CEST)
In the current study nanocellulose was isolated from walnut shell using mechanical and chemical methods. This study highlights the particle size, morphology and these methods’ efficiency in nano structure extraction. The difference between morphology and size of the particles (of the both extracted methods) were investigated by field emission scanning electron microscopy (FESEM). Walnut shell is an agro-waste material with source of lignin and cellulose. Ball mill-ing with different times, in the presence and absence of additive and acid hydrolysis were used as mechanical and chemical methods, respectively. The result showed mechanical method is unable to extract nanoparticle and just reshape the walnut shell. Milling time were also found important in morphology of fiber extracted. FE-SEM images represented that structure mean diameter of using ball mill was 1± 5 μm while hydrolysis acid method extract nano particle with mean diameter of 40± 20 nm.
ARTICLE | doi:10.20944/preprints202106.0191.v1
Subject: Engineering, Automotive Engineering Keywords: nano-composite; blasting; pretreatment; adhesion; microhardness, corrosion resistance
Online: 7 June 2021 (15:14:17 CEST)
In this study, grit blasting pretreatment was used to improve the adhesion and corrosion resistance and microhardness of Ni-W/SiC nanocomposite coatings fabricated using conventional electrodeposition technique. Prior to deposition, grit blasting and polishing (more commonly used) pretreatment were used to prepare the surface of the substrate and the 3D morphology of the pretreated substrates was characterized using laser scanning confocal microscopy. The coatings surface and the cross section morphology were analyzed using scanning electron microscopy (SEM). The chemical composition, crystalline structure, microhardness, adhesion, and the corrosion behavior of the deposited coatings were characterized using energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), microhardness tester, scratch tester and electrochemical workstation, respectively. The results indicated that the grit blasting and SiC addition, improved the microhardness, adhesion and corrosion resistance. The Ni-W-SiC nanocomposites pretreated by grit blasting exhibited the best adhesion strength, up to 36.5 ± 0.75 N. Its hardness was the highest and increased up to 673 ± 5.47Hv and its corrosion resistance was the highest compared to the one pretreated by polishing.
ARTICLE | doi:10.20944/preprints202102.0115.v1
Subject: Engineering, Automotive Engineering Keywords: Soybean biodiesel; Engine performance; Engine emission; Nano-additives
Online: 3 February 2021 (10:45:16 CET)
The present study examines the effect of SiO2 nano-additives on the performance and emission characteristics of a diesel engine fuelled with soybean biodiesel. Soybean biofuel was prepared using the transesterification process. Nano-additives characterisations were done using different tests such as FESEM, XRD, EDS, etc., to study the morphology of nano-additives. For proper blending of nano-additives with biodiesel, the ultrasonication process was used. Surfactant was used for the stabilisation of nano-additives. After making all the combinations of nano fuel blends, physicochemical properties were measured as per ASTM standards. Performance and emissions readings were taken at different load conditions. It was found that with the addition of SiO2 nano-additives, brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) was increased by 3.48-6.39% and 5.81-9.88%, respectively. Significant reduction of CO, CO2, NOx, and smoke emissions were also observed compared to baseline fule due to better combustion efficiency with the use of SiO2 nano-additive.
ARTICLE | doi:10.20944/preprints202005.0185.v1
Subject: Materials Science, General Materials Science Keywords: severe plastic deformation; iron hardness; micro/nano-structure
Online: 11 May 2020 (03:33:40 CEST)
The evolution of metals micro/nano-structure upon severe plastic deformation (SPD) is still far to be theoretically explained, while experimental datasets are persistently growing for several decades. Major problem associated with understanding of SPD is related to a fact that the latter is a synergetic product of several competing physical effects which alter the material micro/nano-structure. In attempt to find deformational boundaries, where predominantly one mechanism determines the micro/nano-structure, in this paper we propose a continuous piecewise model for the analysis of experiments on material hardness vs strain of SPD processed materials. The novelty of this approach lies in its ability to find, as free-fitting parameters, the strain breakpoints which separate different micro/nano-structure modes generated upon SPD process. The model is applied to analyse experimental data for polycrystalline samples of pure iron and two distinctive strain breakpoints are revealed with good accuracies. This finding is in a good agreement with our earlier results on TEM microscopy studies on pure iron polycrystals after SPD treatment.
ARTICLE | doi:10.20944/preprints202211.0533.v1
Subject: Materials Science, Other Keywords: Nano surfaces; Early bone formation; Implant surface; histomorphometry; osseointegration.
Online: 29 November 2022 (03:57:25 CET)
Background: Implant surface topography is a key element in achieving osseointegration. Nanostructured surfaces have shown promising results in accelerating and improving bone healing around dental implants. The main objective of the present clinical and histological study is to compare, at 4 and 6 weeks, (w) bone-to-implant contact in implants having either machined surface (MAC), SLA medium roughness surface or a Nanostructured Calcium-Incorporated sur-face (XPEED®). Methods: 35 mini-implants with 3 different surface treatments (XPEED® (n=16) – SLA (n=13) – Machined (n=6), were placed in the posterior maxilla of 11 patients then, retrieved at either 4 or 6w in a randomized split-mouth study design. Results: The BIC rate measured at 4 and 6w respectively, was: 16.8 % (±5.0) and 29.0 % (±3.1) for MAC surface; 18.5 % (±2.3) and 33.7 % (±3.3) for SLA surface; 22.4 % (±1.3) and 38.6 % (±3.2) for XPEED® surface. In all types of in-vestigated surfaces, the time factor appeared to significantly increase the BIC rate (p < .05). XPEED® surface showed a significantly higher values when compared to both SLA and MAC values at 4w (p < .05). Also, at 6w, both roughened surfaces (SLA and XPEED® ) showed signifi-cantly higher values (p < .05) than turned surface (MAC). Conclusion: Nanostructured Calcium titanate coating is able to enhance bone deposition around implants at early healing stages.
REVIEW | doi:10.20944/preprints202107.0474.v1
Subject: Life Sciences, Biochemistry Keywords: Nano crystallization; Chemotherapeutic agents; Targeting; Morphology; Stabilizer; Cell lines
Online: 21 July 2021 (09:40:09 CEST)
Presently, nano-crystallization is widely accepted for increasing the solubility and biological barrier permeability of poorly soluble drugs. It improves the bioavailability of therapeutic agents, increasing the effectiveness for treating diseased conditions, and could be safely administered by oral, parenteral, or transdermal routes. Drug nanocrystals are drug particles coated with a thin polymer layer to enhance their stability and could be decorated with ligands for active targeting. In addition, nanocrystals, due to their morphological properties, improve cell internalization. Therefore, passive targeting by high cellular uptake and retention in the mononuclear phagocyte system (MPS) may be expected. Drug nanocrystals are formulated by either top-down or bottom-up methods and could be scaled up for industrial manufacturing. In the past few decades, nanocrystal formulation has been increasingly studied to overcome the limitations of BCS Class II and IV chemotherapeutic agents. The study of cytotoxic effects of drug formulation on cell lines gives an insight for estimating its in-vivo biodistribution. This review highlights the role of morphology, stabilizer, and ligand conjugation on drug targeting and cellular uptake in cancer cells, as well as a brief discussion on nanocrystal production.
ARTICLE | doi:10.20944/preprints202003.0312.v1
Subject: Materials Science, Nanotechnology Keywords: graphene oxide; nano composite; ruthenium oxide; supercapacitor; XRD; XPS
Online: 20 March 2020 (09:27:19 CET)
Graphene-oxide (G) was prepared by the Hummers’ method. A G-COOH layer was synthesised using chloroacetic acid and G. To fabricate carboxylated graphene-RuO2 (G-COORu) nano¬¬-composites, RuO2 nano particles were grown on graphene layers using a one-step thermal method, -COOH(G-COOH), and RuCl3. All materials were characterised using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, 13C-nuclear magnetic resonance as well as X-ray photoelectron, Fourier-transform infrared spectroscopy, and Raman. The electrochemical characteristics of the G-COORu supercapacitors were analysed using electrochemical impedance spectroscopy, cyclic voltammetry, constant current charge–discharge tests, and Nyquist impedance plots. The supercapacitors exhibit a specific capacitance of ~125 F g-1 at 100 mA cm-2 within the potential range of 0–1.0 V. The method used here provides a simple approach for the deposition of RuO2 nano particles on graphene layers and can be widened to the fabrication of other classes of hybrids based on G layers for specific technical applications.
ARTICLE | doi:10.20944/preprints201810.0045.v1
Subject: Life Sciences, Other Keywords: Copper nanoparticles, nano-fertilizer, soil, nitrification, nitrification kinetics, toxicity
Online: 3 October 2018 (12:46:58 CEST)
The potential agricultural use of metal nanoparticles (NPs) for slow-release micronutrient fertilizers is beginning to be investigated by both industry and regulatory agencies. However, the impact of such NPs on soil biogeochemical cycles is not clearly understood. In this study, impacts of a commercially-available copper NPs on the soil nitrification kinetics was investigated via batch experiments. The X-ray absorption near edge structure spectroscopy analysis showed that the NPs readily oxidized to Cu(II) and strongly retained in soils with minimum dissolution (<1% of total mass). The Cu2+ (aq) at 1mg/L showed the beneficial effect on the nitrification, an increase in the rate of nitrification kinetics (Vmax). However Vmax was negatively impacted by ionic Cu at 10-100mg/L and CuNP at 1-100 mg/L. The trace metal toxicity of soil nitrifiers seems to be critical in the soil nitrification processes. Among CuNPs, the suppressed nitrification kinetics was concentration dependent at >10mg/L. The reaction products of surface oxidation such as the release of ionic Cu seem to play an important role in suppressing the nitrification process. Considering the potential use of copper NPs as a slow-release micronutrient fertilizer, further studies are needed in heterogeneous soil systems.
ARTICLE | doi:10.20944/preprints201809.0421.v1
Subject: Materials Science, Nanotechnology Keywords: Nanoparticles – Bio-nano interfaces – Electrostatic interactions – Supported Lipid Bilayers
Online: 20 September 2018 (16:29:35 CEST)
The impact of nanomaterials on lung fluids or on the plasma membrane of living cells has prompted researchers to examine the interactions between nanoparticles and lipid vesicles. Recent studies have shown that nanoparticle-lipid interaction leads to a broad range of structures including supported lipid bilayers (SLB), particles adsorbed at the surface or internalized inside vesicles, and mixed aggregates. Today, there is a need to have simple protocols that can readily assess the nature of structures obtained from particles and vesicles. Here we apply the method of continuous variation for measuring Job scattering plots and provide analytical expressions for the scattering intensity in various scenarios. The result that emerges from the comparison between modeling and experimental measurements is that electrostatics plays a key role in the association, but it is not sufficient to induce the formation of supported lipid bilayers.
ARTICLE | doi:10.20944/preprints201809.0376.v1
Subject: Materials Science, Nanotechnology Keywords: polycrystalline nano phosphor; photoluminescence; Eu3+ doped CaSiO3; microemulsion technique
Online: 19 September 2018 (09:04:52 CEST)
A series of Eu3+ doped CaSiO3/SiO2 nano-phosphor powder of controlled grain size, crystalline structure, and chemical composition were synthesized using the microemulsion technique. XRD profiles of samples sintered over 600 of suggested phase shift from amorphous powder grain to more ordered polycrystalline powder of triclinic type wollastonite, CaSiO3, with preferred crystal phase orientation of (112) and tetragonal type cristobalites of SiO2. The grain size, crystallinity, and chemical composition of the host matrix, activator and sensitizer strongly affected both the absorption and emission bands of these samples. The amplitude of both the orange and red emission bands significantly increased with sintering temperature. The emission band is red-shifted with decreasing grain sizes. These bands displayed good sensitivity to ionic concentration of the Si4+, Ca2+, and Eu3+. With increasing Ca2+ ion concentration both the intensity of the red photoluminescence (PL) band increased and a concentration quenching observed. Increase in Si4+ ion concentration led to quenching in PL intensity of both the orange and red bands whereas the amplitude of the blue-band slightly increased. With increasing Eu3+ ion concentration the red-band initially increased whereas it started decreasing at higher sample concentration. In the presence of Ca2+ ion as a sensitizer, the sample showed a remarkable PL property—including—about 100% photon conversion efficiency and a two-fold increase in excitation and emission photons.
ARTICLE | doi:10.20944/preprints201805.0336.v1
Subject: Materials Science, Biomaterials Keywords: 316L; electrodeposition; nano-hydroxyapatite; carbon nanotubes; osteoblasts; gene expression
Online: 24 May 2018 (06:18:52 CEST)
Herein, we evaluated the electrophoretic deposition of nanohydroxyapatite/superhydrophilic multiwalled carbon nanotube composites (nHAp/MWCNT) onto stainless steel biomedical alloys for applications in bone tissue engineering. First, nHAp/MWCNT composites were dispersed into 0.042 mol L−1 of Ca(NO3)2·4H2O + 0.025 mol L−1 NH4H2PO4 electrolytes (pH = 4.8) at two different concentrations. Next, a voltage of −2 V was applied using 316L stainless steel as a working electrode and (0.27 cm2), a high-purity platinum coil wire as the auxiliary electrode, and an Ag/AgCl(3 M) electrode was used as the reference electrode. The nHAp/MWCNT composites were characterized by transmission electron microscopy. The deposited nHAp and nHAp/MWCNT films were characterized by profilometry, scanning electron microscopy, X-Ray diffractometry and Raman spectroscopy. Human osteoblast cells were cultivated with the different materials, and in vitro cytotoxicity was evaluated using lactate dehydrogenase (LDH) assay. The osteogenesis process was evaluated by mRNA levels of the three genes that are directly related to bone repair: Alkaline Phosphatase, Osteopontin and Osteocalcin. We showed that rough, crystalline apatite thin films containing phases of nHAp were successfully deposited onto 316L stainless steel alloys. Also, we noticed that nHAp/MWCNT thin films deposited onto 316L stainless steel alloys upregulated the expression of important genes related to bone mineralization and maturation. Our results strongly support the possibility of this new alternative to modify the surface of metallic biomedical alloys to promote bone tissue regeneration.
ARTICLE | doi:10.20944/preprints201805.0305.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: nano-TiO2; water-based nanolubricant; hot rolling; grain refinement
Online: 22 May 2018 (12:27:13 CEST)
Hot rolling tests of a low-alloy steel were conducted at a rolling temperature of 850 ℃ under different lubrication conditions, including benchmarks (dry condition and water) and water-based nanolubricants containing different concentrations of nano-TiO2 from 1.0 to 8.0 wt%. The effects of nanolubricants on rolling force, surface roughness, thickness of oxide scale and microstructure were systematically investigated through varying nano-TiO2 concentrations. The results show that the application of nanolubricants can decrease the rolling force, surface roughness and oxide scale thickness of rolled steels, and refine ferrite grains. In particular, the nanolubricant containing an optimal concentration (4.0 wt%) of nano-TiO2 demonstrates the best lubrication performance, owing to the synergistic effect of lubricating film, rolling, polishing and mending generated by nano-TiO2.
ARTICLE | doi:10.20944/preprints201609.0109.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: nano-Au particles; NIPAAm hydrogel; plasma treatment; UV grafting
Online: 28 September 2016 (09:49:23 CEST)
In this study, a new type of temperature sensor device was developed. The circular electrode of the thermal sensitive sensor was modified with TMT and O2 plasma to enhance the conductivity by forming a thin SnOxCy layer on the electrode surface. The Nano-Au particles were subjected to O2 plasma pretreatment to form peroxide groups on the surface. The thermally sensitive sensor was made by mixing the above-treated Nano-Au particles with N-isopropylacrylamide (NIPAAm) to form solution and then UV-induced grafting polymerization of the NIPAAm-containing solution onto the electrode substrate. The composite hydrogels on the electrode introduce thermo-sensitive polymeric surface films for temperature sensing. Using ambient environment resistance test to measure the resistance, the LCST (lower critical solution temperature) of Nano-Au (MUA) mixed with NIPAAm hydrogel was found to be 32 °C. At ambient temperatures higher than LCST, the electrode resistance decreases linearly.
ARTICLE | doi:10.20944/preprints202110.0181.v3
Subject: Engineering, Civil Engineering Keywords: Construction practices using nanotechnology applications; nano-modified emulsion stabilisation of granular materials; nano-modified emulsion stabilised layers in highway construction; central plant
Online: 23 December 2021 (10:52:06 CET)
The introduction of any new disruptive technology in a traditionally well-established industry, such as the road construction industry, is usually associated with considerable resistance. This is especially relevant when the new technology is based on the use of granular materials traditionally considered to be of an unacceptable quality in combination with relatively new concepts such as New-age (Nano) Modified Emulsions (NME). In such cases, the fact that the material design methods are based on fundamental scientific principles and have been proven in laboratories and through Accelerated Pavement Testing (APT), may be of little influence. However, the general acceptance of new disruptive technologies, e.g. telecommunications and Information Technologies (IT), have been based on the considerable advantages it presented. The same principles are applicable to the general acceptance and use of NME stabilisation/enhancement of materials in the road construction industry. This article is aimed at the practical cost-effective demonstration of the general application of the use of nanos-silane modified emulsions in the construction of the highest order roads, i.e. inter-city multi-lane highways, lower order roads (including Low-Volume-Roads (LVR)) and even local accesses to farms and in villages/townships. The implementation of NME technologies is directly associated with ease of use, time and cost savings and the addressing and reduction of risks applicable to the use thereof.
ARTICLE | doi:10.20944/preprints202206.0417.v1
Subject: Materials Science, Nanotechnology Keywords: lecithin; ginger oil; essential oil; nano-lipid; drug delivery system
Online: 30 June 2022 (08:00:31 CEST)
Lipid nanoparticles have an interesting part of drug delivery system. In this study, the modification of the convention nano-lipid based soybean lecithin was demonstrated. Ginger oil derived Zingiber officinale was used along with lecithin, cholesterol and span 80 to fabricate nano-lipid (GL nano-lipid) using thin-film method. Through TEM and confocal microscope, GL nano-lipid exposes the liposome- like morphology. The average size of the resultant nanoparticles was 249.1nm with monodistribution (PDI= 0.021). The ζ-potential of GL nano-lipid was negative as similar to as prepared nano-lipid based lecithin. GL nano-lipid express the highly stable over 60 days of storage at room temperature in term of size, ζ-potential. A shift of pH value from alkaline to acid was detected in lecithin nano-lipid, while with the incorporation of ginger oil, pH value of nano-lipid dispersion was around 7.0. Furthermore, due to the rich of shogaol-6 and other active compounds in ginger oil, the GL nano-lipid is endowed with intrinsic antibacterial feature. In addition, the sulforhodamine B (SRB) assay and live/dead imaging revealed the excellent biocompatibility of GL nano-lipid. Notably, GL nano-lipid was capable to carry the hydrophobic agents as curcumin and perform a pH-dependent release profile. A subsequent characterization are a suitable potential for drug delivery system.
ARTICLE | doi:10.20944/preprints201902.0093.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: drift current; diffusion current; mobility; nano-node; model; ALD technology
Online: 11 February 2019 (16:15:49 CET)
A novel drive current model covering the effects of source/drain voltage (VDS) and gate voltage (VGS) and incorporating drift and diffusion current on the surface channel at the nano-node level, especially beyond 28nm node is presented. The effect of the diffusion current added is more satisfactory to describe the behavior of the drive current in nano-node MOSFETs, fabricated with the atomic-layer-deposition (ALD) technology. This breakthrough in model establishment can expose the long and short channel devices together. Introducing the variables of VDS and VGS, the mixed current model more effectively and meaningfully demonstrates the drive current of MOSFETs under the operation of horizontal, vertical, or mixed electrical field. In comparison between the simulation and experimental consequences, the electrical performance is impressive. The error between both is less than 1%, better than the empirical adjustment to issue a set of drive current models.
ARTICLE | doi:10.20944/preprints201811.0364.v1
Subject: Physical Sciences, Applied Physics Keywords: Bio-sensing, Extinction cross-section, Nano-particles, Plasmons, Raman scattering.
Online: 15 November 2018 (14:54:58 CET)
In this paper, the far field and near field optical responses of a gold nanoparticle are studied and simulated numerically. The electromagnetic field was excited by an electric dipole located near one end of the nanorod, which is used to model the emission of a quantum dot. Another excitation method was also simulated in which an incident plane wave is used. The excitation of dark plasmon modes of the gold nanorod is presented. The Poynting equation was solved numerically to study the influence of the gold nanorod on the dipole radiative power. In addition, the extinction cross section of the gold nanoparticle illuminated by the incident plane wave was calculated to estimate the amount of the scattered and absorbed light.
REVIEW | doi:10.20944/preprints201811.0061.v1
Subject: Chemistry, Other Keywords: reverse micelles, biomimetic, confinement, water dynamics, nanoparticles, nano(bio) sensors
Online: 2 November 2018 (13:25:22 CET)
This paper presents an overview of the principal structural and dynamics characteristics of reverse micelles (RMs) in order to highlight their structural flexibility and versatility, along with the possibility to modulate their parameters in a controlled-manner. The multifunctionality in a large range of different scientific fields is exemplified in two distinct directions: a theoretical model for mimicry of biological microenvironment and practical application in the field of nanotechnology and nano-based sensors. RMs represents a convenient experimental approach that limits the drawbacks of the conventionally biological studies in vitro, while the particular structure confers them the status of simplified mimics of cells by reproducing a complex supramolecular organization in an artificial system. The biological relevance of RMs is discussed in some particular cases referring to the confinement and crowding environment, molecular dynamics of water and cell membrane structure. The use of RMs in different range of applications seems to be more promising due to their structural and compositional flexibility, a high efficiency and selectivity being achieved. The advance in nanotechnology is based on developing new methods of nanomaterials synthesis and deposition. This review highlighting the advantages of using RMs in synthesis of nanoparticles with specific properties and in nano (bio)sensors design.
ARTICLE | doi:10.20944/preprints201810.0598.v1
Subject: Materials Science, Biomaterials Keywords: nano-structures; polymer-matrix composites (PMCs); mechanical properties; thermal properties
Online: 25 October 2018 (06:20:41 CEST)
Poly(vinylidene fluoride) nanocomposites processed with different morphologies, such as porous and non-porous films and fibres, have been prepared with silica nanoparticles (SiNPs) of varying diameter (17, 100, 160 and 300 nm) which in turn have encapsulated perylenediimide (PDI), a fluorescent molecule. Structural, morphological, optical, thermal, and mechanical properties of the nanocomposites, with SiNP filler concentration up to 16 wt% were evaluated. Further, cytotoxicity and cell proliferation studies were performed. All SiNPs are negatively charged independently of the pH and more stable from pH 5 upwards. The SiNPs introduction within the polymer matrix increases the contact angle independently of the nanoparticle diameters and the smallest ones (17 nm) improve the PVDF Young modulus from 0.94 ± 0.04 GPa for the pristine polymer film to 1.05 ± 0.06 GPa. Varying filler diameter, physico-chemical, thermal and mechanical properties of the polymer matrix were not significantly affected. Finally, the SiNPs inclusion does not induce cytotoxicity in murine myoblasts (C2C12) after 72 h of contact and proliferation studies reveal that the prepared composites represent a suitable platform for tissue engineering applications, as they allow to combine the biocompatibility and piezoelectricity of the polymer with the possible functionalization and drug encapsulation and release of the SiNP.
REVIEW | doi:10.20944/preprints201809.0266.v1
Subject: Materials Science, Nanotechnology Keywords: nano hybrids, nanocomposites, sol-gel, in situ synthesis, metal oxides
Online: 14 September 2018 (13:38:47 CEST)
Hybrid inorganic-polymer nanocomposites can be employed in diverse applications due to the potential combination of desired properties from both the organic and inorganic components. The use of novel bottom-up in situ synthesis methods for the fabrication of these nanocomposites is advantageous compared to top-down ex situ mixing methods, as it offers increased control over the structure and properties of the material. In this review, the focus will be on the application of the sol-gel process for the synthesis of inorganic oxide nanoparticles in epoxy and polysiloxane matrices. The effect of the synthesis conditions and the reactants used on the inorganic structures formed, the interactions between the polymer chains and the inorganic nanoparticles, and the resulting properties of the nanocomposites are appraised from several studies over the last two decades. Lastly, alternative in situ techniques and the applications of various polymer-inorganic oxide nanocomposites are briefly discussed.
REVIEW | doi:10.20944/preprints201805.0027.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: flexible electronics; nano-fabrication; top-down approaches; bottom-up approaches
Online: 2 May 2018 (11:51:13 CEST)
Recent progress in the fabricating flexible electronics has been developed significantly due to the increased interest of the flexible electronics which can be applied to enormous fields not only to conventional electronic devices but to bio/eco electronic devices. Flexible electronics can be applied to wide range of fields such as flexible display, flexible power storage, flexible solar cells, wearable electronics and healthcare monitoring devices. Recently, flexible electronics are being attached on the skin and even implanted into human body to monitor the bio-signals and for treatment purpose. To improve the electrical characteristic and the mechanical properties of flexible electronics, nanoscale fabrications using novel nano-materials are required. Advanced in nanoscale fabrication methods allow construction of the active materials that can combine with the ultra-thin soft substrate to form flexible electronics with high performances and reliability. In this review, wide range of nanoscale fabrication methods for flexible electronics classified in either top-down or bottom-up approaches such as conventional photolithography, soft lithography, nanoimprint lithography, growth, assembly and chemical vapor deposition(CVD) will be reported with specific fabrication processes and results. Here, our aim is to introduce various fabrication methods that can be used to fabricate the flexible electronics.
ARTICLE | doi:10.20944/preprints202201.0030.v1
Subject: Engineering, Civil Engineering Keywords: New-age (Nano) Modified Emulsion (NME) stabilisation; identifying construction problems; preventing construction related problems; material related problems; constructability using nanotechnology applications; nano-silane stabilisation of granular materials; construction quality control problems; construction equipment problems; practical implementation of nano-silane stabilisation.
Online: 11 January 2022 (10:37:34 CET)
The use of New-age (Nano) Modified Emulsions (NME) for the stabilisation of marginal materials for use in the upper-pavement layers of roads have been proven in laboratories, through Accelerated Pavement Tests (APT) and in practice. In addition, material design methods have been developed based on the scientific analysis of granular material mineralogy and the chemical interaction with the binder to design a material compatible NME stabilising agent for naturally available (often marginal) materials. However, the introduction of any new disruptive technology in a traditionally well-established industry, such as the road construction industry, is usually associated with considerable resistance. This is especially relevant when the new technology enables the use of granular materials traditionally considered to be of an unacceptable quality in combination with relatively new concepts such as New-age (Nano) Modified Emulsions (NME). In practice, few road construction projects are without any problems. The introduction of new-technologies obviously makes it an easy target to blame for any non-related problem that may arise during construction. This article aims to assist in pre-empting, recognising, preventing and resolving material or non-material related construction problems through the correct identification of the cause of the problem and recommending the best, most cost-effective way to correct any deficiencies on site.
Subject: Physical Sciences, Other Keywords: education; neuroscience; nano-robots; financial markets; financial options; security; computation; optimization
Online: 25 September 2020 (03:03:07 CEST)
Of course, now we know that quantum mechanics has been a fundamental structure of our world since our universe came into being. However, it has been only a century since the experimental and theoretical discovery of quantum mechanics and its extensions into many implications and applications. In particular, there are implications across many disciplines that most likely will affect education, health, security, etc. Examples are given of the need for starting education as early as possible in schools, the use of nano-robots to deliver drugs targeted to specific molecular sites, to developing new cryptographic systems to safeguard our privacy.
ARTICLE | doi:10.20944/preprints202009.0447.v1
Subject: Materials Science, Nanotechnology Keywords: nano- and micro-sized TiO2; photocatalytic efficiency; photoelectrochemical characterization; environmental remediation
Online: 19 September 2020 (05:11:43 CEST)
The size of TiO2 (either nanometric or micrometric) can significantly affect both its photocatalytic and photoelectrochemical properties, thus altering the photooxidation of organic pollutants in air or water. The purpose of this work is to give an account of the photoelectrochemical and photocatalytic features of some nano- and micro-sized TiO2 commercial powders towards a model reaction, the photooxidation of acetone. Cyclic voltammograms (CV) of TiO2 particulated electrodes under UV illumination experiments were carried out in either saturated O2 or N2 solutions for a direct correlation with the photocatalytic process. In addition, the effect of different reaction conditions on the photocatalytic efficiency under UV light in both aqueous and gaseous phases was also investigated. CV curves with the addition of acetone under UV light showed a negative shift of the photocurrent onset, confirming the efficient transfer of photoproduced reactive oxygen species (ROSs), e.g., hydroxyl radicals, or holes to acetone molecules. The photocatalytic experiments showed that the two nano-sized samples exhibit the best photocatalytic performance. The different photoactivity of the micro-sized samples is probably attributed to their morphological differences, affecting both the amount and distribution of free ROSs involved in the photooxidation reaction.
ARTICLE | doi:10.20944/preprints202007.0126.v1
Subject: Engineering, Mechanical Engineering Keywords: Coarse Grain Models; Water Models; Nanoscale Evaporation; Nano Channels; Molecular Dynamics
Online: 7 July 2020 (11:03:25 CEST)
Evaporation studies of water using classical molecular dynamics simulations are largely limited due to its high computational expense. We aim at addressing the computational issues by developing a coarse grain model for evaporation of water on solid surfaces by combining four water molecules into a single bead. Most commonly used mono atomic pair potentials like Lennard Jones, Morse, Mie and three body potential like Stillinger-Weber are optimized using a combination of Genetic algorithm and Nelder-Mead algorithm. Among them, Stillinger-Weber based model shows excellent agreement of density and Enthalpy of vaporization with experimental results for a wide range of temperatures. Further, the new water model is used to simulate contact angle of water and thin film evaporation from surfaces with different wettabilities.
ARTICLE | doi:10.20944/preprints201902.0250.v1
Subject: Physical Sciences, Applied Physics Keywords: rare-earth garnets; optical constants; envelope method; nano-composites; magneto-optics
Online: 27 February 2019 (09:09:58 CET)
Amorphous ferrite-type rare-earth (RE) substituted garnets and garnet-oxide nanocomposite layers are prepared on clear glass substrates by using RF magnetron sputter-deposition process. By using a combination approach employing custom-built spectrum-fitting software in conjunction with Swanepoel’s envelope method, the spectral dispersion function of optical constants and the layer thicknesses are derived accurately from the transmission spectra of the as-deposited samples. The effects of excess metal-oxides added to the base material systems during the co-deposition process are found to affect the refractive index and the optical absorption coefficients of garnet-oxide composites. A number of optical constant datasets are presented, enabling the experimentalists to design nanophotonic or integrated-optics devices employing these functional materials.
ARTICLE | doi:10.20944/preprints201708.0073.v1
Subject: Mathematics & Computer Science, Other Keywords: carbon nano-fibers; 3-D braided composite material; damage detection; SVD
Online: 21 August 2017 (10:27:05 CEST)
Aiming at the damage detection and continuous monitoring of high efficiency composite structure, the method of carbon nano sensor embeded in the 3-D braided composite material specimen was put forward and the method of damage location for 3-D braided composite material was described. In this paper, the mechanical and electrical characteristics of carbon nano-fiber were analyzed. Considering the massive data of the health monitoring of composite processing, to ensure that the system has good real-time performance, quaternary matrix Singular Value Decomposition algorithm is proposed to simplify data and improve the efficiency of the algorithm. The existence of injury is determined and the damage location is calculated by comparing with key features of healthy specimen. Experimental results prove the method is feasible and effective.
ARTICLE | doi:10.20944/preprints201702.0013.v1
Subject: Materials Science, Nanotechnology Keywords: nano-cube; heterostructures; bottom-up growth; electron microscopy; bandgap; Ag-WO3
Online: 4 February 2017 (09:23:00 CET)
A new class of nano-cube core-shell heterostructures containing Ag coating on the top of WO3 was fabricated. Physical vapor deposition was used to produce WO3 based nano-heterostructures. All kind of wet toxic chemical process was avoided to make the process simple and contaminant free. Sputtering of WO3 and a subsequent thermal annealing process was done to create nano-cubes of WO3. After that, sputtering of Ag was performed to form the Ag-WO3 core-shell nano-heterostructures (CSNH). The CSNHs were characterized using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD) and UV-vis spectroscopy. The morphologies, elemental analysis, interfaces, crystallinity, phases, and chemical compositions were analyzed. The bottom-up growth of WO3 nanocubes was studied using different time periods at 900°C. Ag coating was also studied before and after annealing. Finally, an optical property (band gap) was also analyzed using Tauc plot derive from absorption spectra. The tailoring the band gap of WO3 from ~2.9eV to ~ 2.45 eV was observed while Ag-WO3 CSNH formed.
ARTICLE | doi:10.20944/preprints202212.0396.v1
Subject: Materials Science, Polymers & Plastics Keywords: Spin Crossover; (Coaxial)-electrospinning; Triazole Complexes; nano fibers; PMMA; Coordination Chemistry; Composites
Online: 21 December 2022 (09:19:47 CET)
We synthesized iron(II)-triazole spin crossover compounds of the type [Fe(atrz)3]X2 and incorporated and deposited them on electrospun polymer nanofibers. In view of possible applications, we chose iron(II)-triazole-complexes that are known to exhibit spin crossover close to ambient temperature. Therefore we used the complexes [Fe(atrz)3]Cl2 and [Fe(atrz)3](2ns)2 (2ns = 2Naphthalenesulfonate) and analyzed them with IR-, UV/Vis and Mossbauer spectroscopy and with a SQUID magnetometer. The synthesized complexes were then in one attempt deposited on fibers of polymethylmethacrylate (PMMA) and in another attempt incorporated into core-shell like PMMA fiber structures. This was done via two different electrospinning methods. Deposition was performed by uniaxial electrospinning and incorporation was performed by coaxial electrospinning. The obtained polymer-complex-composites were then further investitgated by the same methods as the pure complexes as well as by SEM pictures and EDX measurements. The analysis by UV/Vis spectroscopy, Mössbauer spectroscopy and temperature-depended magnetic measurements with the SQUID magnetometer showed that the spin crossover properties were maintained and were not changed after the electrospinning processes and that the complexes were not harmed during the procedure.
ARTICLE | doi:10.20944/preprints202112.0308.v1
Subject: Physical Sciences, Other Keywords: Nano-ZrO2+3 mol.%Y2O3; Hydrogen generation; Kinetics; Thermal processes; Adsorption, Desorption.
Online: 20 December 2021 (10:50:44 CET)
The physicalchemistry properties and crystal structure of were nano-ZrO2+3mol.%Y2O3 determined. The kinetics of the formation of H2 as a result of the decomposition of H2O on the surface of nano-ZrO2+3mol.%Y2O3 was studied. Effects of adsorption and desorption process on ZrO2+3 mol.%Y2O3 nanoparticles were studied at different (T=400÷10000C) temperature. The study of H2 in thermal processes at nano-ZrO2+3 mol.%Y2O3 system increased. Such an increase in H2 generation in comparison with a pure H2O as thermal processes had formedactive centers for H2O decomposition on the surface of the catalyst at the expense of δ-electrons emitted on the surface of nano-ZrO2+3 mol.%Y2O3. This showed that the dimensions of the studied nanoscale particles systems are comparable to the free running distance of energy carriers generated by of nano-ZrO2+3 mol.%Y2O3 as a result of thermal processes. These results are promising for hydrogen generation by waer spliting in near future.
ARTICLE | doi:10.20944/preprints202109.0524.v1
Subject: Engineering, Civil Engineering Keywords: ultra high performance concrete (UHPC); concrete; compression strength; durability; nano additions; additions.
Online: 30 September 2021 (15:23:02 CEST)
This paper seeks to optimize the mechanical and durability properties of ultra-high performance concrete (UHPC). To meet this objective, concrete specimens were manufactured by using 1,100 kg/m3 of binder, water/binder ratio 0.20, silica sand and last generation of superplasticizer. Silica fume, metakaolin and two types of nano silica were used for improving the performances of the concrete. Additional mixtures included 13mm long OL steel fibers. Compressive strength, electrical resistivity, mercury intrusion porosimetry tests and differential and thermogravimetric thermal analysis were carried out. The binary combination of nano silica and metakaolin, and the ternary combination of nano silica with metakaolin and silica fume, led to the best performances of the UHPC, both mechanical and durable performances.
ARTICLE | doi:10.20944/preprints202010.0099.v1
Subject: Physical Sciences, Acoustics Keywords: Au nano-pore; surface plasmon polariton; pyramidal aperture; intraband emission; nanoslit array
Online: 5 October 2020 (16:57:24 CEST)
We fabricated the nano-aperture plasmonic platforms for single molecule detection and other various applications such as infrared thermal emission device. The nano-apertures including the nanopores on the pyramid, and the nano-slits on the Au flat membrane were fabricated using a Ga ion focused ion beam drilling technique, followed by high energy electron beam irradiations dependent upon the electron beam current density. The nanopores with a few nanometer size and the nanoslit array with order of ~ 100 nm width were fabricated. Optical characteristics for the various nanoslits were examined dependent upon the slit opening width and sample thickness. The broad emission spectra from the (7x 7) slit array are obtained from spp-mediated emission in the visible and infrared region. A sharp strong infrared emission peak is also obtained due to Au nanoparticle. The fabricated Au platform can be utilized as single molecule sensor and infrared thermal emission device.
ARTICLE | doi:10.20944/preprints202102.0443.v1
Subject: Keywords: critical sized bone defect; bone tissue regeneration; nano-gelatin/ hydroxyapatite fiber (NGF); metformin.
Online: 19 February 2021 (14:35:11 CET)
Tissue engineering and regenerative medicine has gradually evolved as a promising therapeutic strategy to the modern healthcare of the aging and diseased population. In this study, we developed a novel nano-fibrous scaffold and verified its application in the critical bone defect regeneration. The metformin-incorporated nano-gelatin/hydroxyapatite fibers (NGF) was produced by electrospinning, cross-linked, and then characterized by XRD and FTIR. Cytotoxicity, cells adhesion, cell differentiation, and quantitative osteogenic gene and protein expression were analyzed by bone marrow stem cells from rat. Rat forearm critical bone defect model was performed for the in vivo study. The nano-gelatin/hydroxyapatite fibers (NGF) were characterized by their porous structures with proper interconnectivity without significant cytotoxic effects; the adhesion of bone marrow stem cells on the nano-gelatin/hydroxyapatite fibers (NGF) could be enhanced. The osteogenic gene and protein expression were upregulated. Post implantation, the new regenerated bone in bone defect was well demonstrated in the NGF samples. We demonstrated that the metformin-incorporated nano-gelatin-hydroxyapatite fibers greatly improved healing potential on the critical sized bone defect. Although metformin-incorporated nano-gelatin/hydroxyapatite fibers had advantageous effectiveness during bone regeneration, further validation is required before it can be applied to clinical applications.
ARTICLE | doi:10.20944/preprints202102.0280.v1
Subject: Life Sciences, Biochemistry Keywords: Double stranded RNA; Nano clay; Phytophthora infestans; Potato; Spray Induced gene silencing (SIGS)
Online: 11 February 2021 (11:07:19 CET)
Phytophthora. infestans is a well known late blight causing oomycetes pathogen. It evolves and adapts to the host background and new fungicide molecules rapidly within a few years of their release, may be due to the predominance of transposable elements in its genome. Frequent and huge applications of fungicides cause environmental concerns. Here we developed target specific RNA interference based molecules, that are capable of effectively reducing the late blight infection. cDNA microarray expression data was used for the selection of genes involved in the early stage of infection process, sporulation etc. The in vitro synthesis of double stranded RNA molecule, targeting SDH, EF-1α, GPI-HAM344, PLD-3 and HSP-90 encoding genes revealed the reduction in growth, sporulation and symptom expression, which were subsequently assessed by culture bioassay, detached leaf assay and topical application methods. The multiple genes targeted dsRNA nano clay sprayed plants showed enhanced disease resistance (4% disease severity) and least sporulation (<1x103), compared to naked dsRNA spray. Use of nano clay was assumed to be involved in the effective delivery, protection and boosting the action of RNAi in potato plants. A significant difference in the growth, sporulation count, disease severity and reduced expression of the genes and confocal microscopy imaging authenticates the effects of SIGS on late blight disease progression. Our research demonstrated that topical dsRNA nano clay spray under the open-air environment could be an alternative to chemical fungicides and transgenic approaches as a novel plant protection strategy for late blight in an environmentally friendly manner.
REVIEW | doi:10.20944/preprints202007.0318.v1
Subject: Materials Science, Nanotechnology Keywords: agricultural industry; antibacterial; antimicrobial; green synthesis; gold; nano-biotechnology; nanoparticles; silver; sustainable development
Online: 15 July 2020 (06:13:43 CEST)
Currently, metal nanoparticles have varied uses for different medical, pharmaceutical, and agricultural applications. Nano-biotechnology combined with green chemistry has great potential for the development of novel and necessary products that benefit human activities, while encourages the reduction of hazardous reagents for nanoparticle production. Green chemistry has an important role due to its contribution to unconventional synthesis methods of gold and silver nanoparticles from plant extracts, which have exhibited antimicrobial potential among other outstanding properties. Biodiversity-rich countries need to collect and convert knowledge from biological resources into processes, compounds, methods, and tools, which need to be achieved along with sustainable use and exploitation of biological diversity. Therefore, this review focuses on the importance of metal nanoparticles, the use of plant extract for their synthesis as well as other available methods, and the relevant antimicrobial activity that can be exploited in a sustainable model of agricultural management through a modern nanotechnological approach.
REVIEW | doi:10.20944/preprints201906.0112.v1
Subject: Engineering, Mechanical Engineering Keywords: porosity; atmospheric plasma spraying; chromium oxide; porosity measurement; multi-layer coatings; nano-coatings
Online: 13 June 2019 (07:49:09 CEST)
Porosity in plasma sprayed coatings is vital for most engineering applications. It is either advantageous or disadvantageous depending on the functionality of the coating and the immediate working environment. Consequently, the formation mechanisms and development of porosity has been extensively explored to find out modes of controlling porosity in plasma sprayed coatings. In this work, a comprehensive review of porosity on plasma sprayed coatings is established. The formation and development of porosity on plasma sprayed coatings are governed by set spraying parameters. Optimized set spraying parameters have been used to achieve the most favorable coatings with minimum defects. Even with the optimized set spraying parameters, defects like porosity still occur. Here, we discuss other ways that can be used to control porosity in plasma sprayed coating with emphasis to atmospheric plasma sprayed chromium oxide coatings. Techniques like multi-layer coatings, nano-structured coatings, doping with rare earth elements, laser surface re-melting and a combination of the above methods have been suggested in adjusting porosity. The influences of porosity on properties of plasma sprayed coatings and the measurement methods of porosity have also been reviewed.
ARTICLE | doi:10.20944/preprints201812.0325.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: multiple valued logic (MVL); CNFET; energy-efficiency; nano-electronics; ternary logic, adder, ALU
Online: 28 December 2018 (03:54:46 CET)
Traditional silicon binary circuits continue to face challenges such as high leakage power dissipation and large area of interconnections. Multiple-Valued Logic (MVL) and nano-devices are two feasible solutions to overcome these problems. In this paper, we present a novel method to design ternary logic circuits based on Carbon Nanotube Field Effect Transistors (CNFETs). The proposed designs use the unique properties of CNFETs, e.g., adjusting the Carbon Nanotube (CNT) diameters to have the desired threshold voltage and have the same mobility of P-FET and N-FET transistors. Each of our designed logic circuits implements a logic function and its complementary via a control signal. Also, these circuits have a high impedance state which saves power while the circuits are not in use. We show a more detailed application of our approach by designing a two-digit adder-subtractor circuit. We simulate the proposed ternary circuits using HSPICE via standard 32nm CNFET technology. The simulation results indicate the correct operation of the designs under different process, voltage and temperature (PVT) variations. Moreover, we designed a two-digit adder/subtractor and a power efficient ternary logic ALU based on the proposed gates. Simulation results show that the two-digit adder/subtractor using our proposed gates has 12X and 5X lower power consumption and PDP (power delay product) respectively, compared to previous designs.
ARTICLE | doi:10.20944/preprints201712.0189.v1
Subject: Materials Science, Nanotechnology Keywords: micro/nano-structured alloy; mechanical properties; in-situ tensile; deformation mechanism; research progress
Online: 27 December 2017 (06:39:22 CET)
Metal and alloy toughening was the core and long-term research direction in materials filed. As grain size had bimodal distribution, micro/nano-structured alloys presented excellent comprehensive mechanical properties, and this had become one of the research hotspots and developing trends in the field of nanotechnology. In-situ tensile test was a direct and effective method to study the deformation mechanism of materials, which revealed the multiple mechanisms responding to feature grain sizes and provided reliable experimental means and research technique. Research on development of in-situ technique and its applications in mechanical properties was reviewed in this paper according to the recent advances on the modern mechanical properties for high strength and high plasticity alloy at home and abroad. The disadvantages of the present study of preparation methods and investigation techniques for high-performance alloy had been concluded. Finally, the development prospects of high strength and high plasticity alloy materials were analyzed.
ARTICLE | doi:10.20944/preprints202101.0336.v1
Subject: Engineering, Automotive Engineering Keywords: Particle packing; packaging models; packaging density; concrete; addition; nano addition; ultra-high-performance concrete
Online: 18 January 2021 (12:44:45 CET)
This paper describes the packaging models that are fundamental for the design of ultra-high-performance concrete (UHPC), and their evolution. They are divided into two large groups: continuous and discrete models. The latter are those that provide the best answer in obtaining an adequate simulation of the packing of the particles up to nanometric size. This includes the interaction among the particles by means of loosening and wall coefficients, allowing a simulation of the virtual and real compactness of such particles. In addition, a relationship between virtual and real compactness is obtained, through the compaction index, which may simulate the energy of compaction that the particles undergo in their placement in the mold. The use of last-generation additives allows such models to be implemented with water-cement (w/c) ratios close to 0.18. However, the premise of maximum packing as a basic pillar for the production of UHPC should not be the only one. The cement hydration process affected by nanoadditions and the ensuing effectiveness in the properties in both fresh and hardened state according to the respective percentages in the mixture should also be studied. An adequate ratio and proportion of these additions may lead to an obtaining of better results even with lower levels of compactness.
REVIEW | doi:10.20944/preprints202010.0438.v1
Subject: Materials Science, Biomaterials Keywords: conversion efficiency; GaAs substrate; light absorption; nano-grating structures; reflection loss; simulation; solar cells
Online: 21 October 2020 (13:28:28 CEST)
At present, the world is now passing a very far different time than normal situation due to the COVID-19 pandemic crisis. The global life-style and human civilization is currently progressing with down-stream that affecting almost every sectors necessary for human civilizations except the current environmental situation. To control the COVID-19 spreading, most of the countries are following lockdown process that reduces human mobility, thus reducing the CO2 emission to the environment. Though the COVID-19 pandemic is a blessing for the present environment, however, the post-COVID world will face a massive thrust of energy and only conventional energy resources may not be enough to mitigate the energy demands. Solar power generation technology mainly the photovoltaic (PV) systems and their advancement can be the leading possibilities to minimize the gap between the power demand and generation. It is now time to think how we can improve the PV power generation in future and the post-COVID world. In this encyclopaedia communication, we report on Nano-technological approach to improve the conversion efficiency of GaAs solar cells. We have designed and optimized several types of nano-structured assemblies that can be implemented to reduce the front surface incident light reflection losses thus can assist to improve the conversion efficiency of GaAs solar cells.
ARTICLE | doi:10.20944/preprints201906.0239.v1
Subject: Arts & Humanities, Art History & Restoration Keywords: marble black crust; carbon nano particles; soluble dust; blue-green algae (cyanophyceae); humic substances
Online: 24 June 2019 (09:22:15 CEST)
The science on the anthropogenic airborne aerosols impacting upon the World Heritage marble monument, the Taj Mahal, at Agra has been studied in the light of modern physico-chemical approaches. The study is an effort to understand yet unrecognized airborne species which were found on the surface of the Taj Mahal monument. These species have been analyzed in the light of current analytical methods to impart characterization features and their possible impacts on the surface of the marble. Chemical constituents of these substrates which were incorporated over the top surface of the monument have been identified. Interestingly, the carbon particulates which were thought in the micro level, popularly called “particulate matters” has now been identified even in the nano domain entity, which are chemically more reactive, have been found on the surface of the monument. Because of their high chemical activity these nano carbons do play newer chemistry in the presence of air and sunlight generating several reactive oxygen species (ROS).These ROS are capable to respond to complicated chemical reactions on the surface of the marble in association with deposited cyanophyceae and other deposits of plant origin causing rapid degradation. This study provides the nature of onslaught borne out by such monument exposed under the prevalent smoggy environmental scenario.
ARTICLE | doi:10.20944/preprints201903.0077.v1
Subject: Materials Science, Nanotechnology Keywords: γ-ray irradiation; surface plasmon resonance; fiber sensor; nano-particles; cladding embedded optical fiber
Online: 6 March 2019 (11:37:09 CET)
The effect of γ-ray irradiation on surface plasmon resonance (SPR) sensing capability of refractive index (n = 1.418–1.448) of the silica glass optical fiber comprised of germano-silicate glass cladding embedded with Au nano-particles (NPs) was investigated. As the γ-ray irradiation increased from 1 hour to 3 hours with the dose rate of 1,190 Gy/h, the morphology of the Au NPs and the SPR spectrum were found to change. The average diameter of Au NPs increased with the aspect ratio from 1 to 2 and the nano-particles became grown to the clusters. The SPR peak wavelength shifted towards longer wavelength with the increase of total dose of γ-ray irradiation regardless of the corresponding refractive indices. The SPR sensitivities (wavelength/refractive index unit, nm/RIU) also increased from 407 nm/RIU to 3,553 nm/RIU, 1,483 nm/RIU, and 2,335 nm/RIU after the γ-ray irradiation at the total dose of 1,190 Gy, 2,380 Gy, and 3,570 Gy, respectively.
ARTICLE | doi:10.20944/preprints201801.0136.v1
Subject: Materials Science, Nanotechnology Keywords: polymer-drug association; inclusion nano-complex; an amphiphilic polymer; polysoaps; antibiotic resistance; ampicillin trihydrate
Online: 16 January 2018 (07:56:15 CET)
Biocompatible polymeric materials with potential to form functional structures in association with different therapeutic molecules have a high potential for biological, medical and pharmaceutical applications. Therefore, the protective capability of the inclusion nano-Complex formed between the sodium salt of poly(maleic acid-alt-octadecene) and a β-lactam drug (ampicillin trihydrate) on the chemical, enzymatic and biological degradation was evaluated. PAM-18Na was produced and characterized as reported previously. The formation of polymeric hydrophobic aggregates in aqueous solution was determined, using pyrene as a fluorescent probe. Furthermore, the formation of polymer-drug nano-complexes was characterized by Differential Scanning Calorimetry-DSC, viscometric, ultrafiltration/centrifugation assays, zeta potential and size measurements by dynamic light scattering-DLS. The PAM-18Na capacity to avoid the chemical degradation was studied through stress stability tests. The enzymatic degradation was evaluated from a pure β-lactamase, while the biological degradation was determined by different β-lactamase producing Staphylococcus aureus strains. When ampicillin was associated with PAM-18Na, the half-life time in acidic conditions increased, whereas both the enzymatic degradation and the minimum inhibitory concentration decreased to a 90 and 75%, respectively. These results suggest a promissory capability of this polymer to protect the β-lactam drugs against chemical, enzymatic and biological degradation.
REVIEW | doi:10.20944/preprints202006.0200.v1
Subject: Life Sciences, Other Keywords: exosomes; micro vesicles; extracellular vesicles; mesenchymal stromal cells (MSC); miRNA; cell therapy; artificial nano particles
Online: 16 June 2020 (07:57:00 CEST)
Extracellular vesicles (EV) such as exosomes, are newly recognized fundamental, natural and physiologic particles of life that seemingly are involved all biologic processes and clinical diseases. Due to their universal involvements, understanding the nature and the potential therapeutic uses of these nano-vesicles requires innovative experimental approaches, in virtually every field. Of the EV group, exosome nano-vesicles and larger companion extracellular micro vesicles (MV) can mediate completely new phenomena dependent on intercellular transfer of proteins and selected RNAs; particularly miRNAs, between donor and targeted cells to elicit epigenetic alterations inducing functional cellular changes. These recipient acceptor cells are nearby (paracrine transfers) or far away after distribution via the circulation (endocrine transfers). The major properties of such vesicles seem to have been conserved over eons, suggesting that they may have ancient evolutionary origins arising perhaps even before cells in the primordial soup from which life evolved. Their potential ancient evolutionary attributes may be responsible for the ability of some modern day exosomes to withstand unusually harsh conditions; perhaps due to unusual membrane lipid compositions. This is exemplified by maternal milk exosome survival of the neonatal acid/enzyme rich stomach. It is postulated that this also applies to their durable presence in phagolysosomes; suggesting unique intracellular release of contents. A major issue discussed is the generally poorly realized superiority of these naturally evolved nano vesicles to therapies compared human engineered artificial nanoparticles; say for treatment of cancers.
ARTICLE | doi:10.20944/preprints202204.0199.v1
Subject: Chemistry, Organic Chemistry Keywords: Catalyst; antibacterial activity; solvent-free conditions; heterogeneous catalysis; Synthesis; cyanopyridines; pyrimidines; nano-structured Na2CaP2O7; catalyst recovery
Online: 21 April 2022 (09:26:25 CEST)
A facile and novel synthesis of thirteen 2-amino-3-cyanopyridine derivatives 5(a-m), by a one-pot multicomponent reaction (MCRs), is described for the first time, starting from aromatic aldehydes, malononitrile, methyl ketones, or cyclohexanone and ammonium acetate in the presence of the nanostructured diphosphate Na2CaP2O7 (DIPH) at 80 °C, under solvent-free conditions. These compounds were synthesized in short reaction times with good to excellent yields (84-94%). The diphosphate Na2CaP2O7 is used as an efficient catalyst, environmentally, easy handling, non-toxic, stable, and reusable. Our study was strengthened by the synthesis of five new pyrido[2,3-d]pyrimidine derivatives 6(b, c, g, h, j) by intramolecular cyclization of 2-amino-3-cyanopyridines 5(b, c, g, h, j), with formamide. The synthesized products were characterized by FT-IR, SEM, XRD, TEM, 1H NMR, 13C NMR, TLC, and BET. The operating conditions were optimized using a model reaction in which the catalyst amount, temperature, time, and solvent effect were evaluated. The antibacterial activity was tested against Gram-positive and Gram-negative strains for the synthesized compounds.
ARTICLE | doi:10.20944/preprints201905.0129.v1
Subject: Materials Science, Other Keywords: Alkaline copper quat (ACQ); Boric acid (BA); Micronized copper quat (MCQ); Nano boron (NB); Corrosion test
Online: 10 May 2019 (14:36:07 CEST)
In this study, the corrosion performances of ammonium copper quat (ACQ) and boric acid (BA) wood preservatives were investigated, with micronized copper quat (MCQ) and nano boron (NB) used as reference materials. In the study, Scots pine (Pinus sylvestris L.) wood samples were impregnated according to the full-cell process method with ACQ at 2.4% concentration, BA at 4% and MCQ and NB at 1%. The ACQ- and BA-impregnated samples were then impregnated for a second time using five different water-repellent materials: tall oil, linseed oil, sodium silicate, methyl hydrogen silicone and N'-N- (1, 8-Naphthalyl) hydroxylamine. Polyethylene glycol (PEG) 600 and aluminum sulfate were introduced as single impregnations in the form of homogeneous mixtures with the ACQ and BA. The corrosion properties of the impregnated and control samples, including metal weight loss (MWL) and corrosion depth, were examined. As a result, the MWL values of the ACQ-impregnated samples showed an increase compared to the control group. The MWL values of the MCQ-impregnated samples were lower than those of the samples impregnated with ACQ, whilst the MWL values of the BA-impregnated samples were higher than those of the samples impregnated with NB.
ARTICLE | doi:10.20944/preprints202301.0478.v1
Subject: Social Sciences, Other Keywords: Nanotechnology; Risk assessment and management; safety and health; Nano worker; DOSH guideline; IRGC framework; policy advice; Malaysia
Online: 26 January 2023 (10:41:49 CET)
In its 8th Malaysia Plan (MP*), the Malaysian government has given nanotechnology development a high priority and has been made a Strategic Research (SR) programme. Consequently, an exhaustive and long-term approach is essential. Additionally, specific laws are required to provide an optimal health and safety environment for workers. Consequently, the current study intends to assist Malaysian policymakers in promoting improved safety, risk assessment, and management for nanotechnology workplaces, as well as drafting a comprehensive policy for the recently released DOSH guideline in 2018. Utilizing a unique methodology, this study evaluated the assessment and management of nanotechnology health and safety risks in Malaysia using the international risk governance council (IRGC) framework. In addition to document analysis, n = 20 semi-structured interviews were conducted with representatives of several nanotechnology platforms to collect data that was then analyzed thematically. The research evaluated current workplace safety regulations and laws. Consequently, we propose a future dynamic strategy for Malaysian nanotechnology with more favourable upgrades supported by increased concentrations in the following areas: I policy creation, ii) comprehensive management system, iii) knowledge transfer, and iv) infrastructure management. In addition, the findings highlight the need of cross-sectional communication in bridging existing gaps. This study laid the groundwork for a more systematic and comprehensive health and safety strategy.
ARTICLE | doi:10.20944/preprints202208.0521.v1
Subject: Physical Sciences, Applied Physics Keywords: ZnO crystallite; random laser; excitons; stimulated emission; polydisperse powder; thin film; hexagonal microdisks; monodisperse nano-powder; nanophotonics
Online: 30 August 2022 (10:45:02 CEST)
A comparative analysis of the features of UV- stimulated emission (SE) of various types of disorder active materials based on ZnO crystallites for a random laser (RL) was carried out. The superlinear increase in the intensity of the UV photoluminescence (PL) band of polydisperse nano- microcrystalline (PNMC) ZnO powder at a wavelength of λ = 387 nm and some narrowing of its half-width in the range of 20-15 nm with increasing pump intensity indicate random lasing with incoherent feedback (FB). Properties of similar UV PL bands under the same conditions from a thin film containing hexagonal ZnO microdisks, as well as samples of monodisperse ZnO nanopowder indicate stimulated emission with coherent feedback. It is shown that, among the studied materials, the PNMC ZnO powder with crystallites contained nano-grains with is the most suitable for creating a laser with incoherent feedback at room temperature. The dominant factor of UV SE in PNMC ZnO powder is radiation transitions under exciton - exciton scattering conditions. The possible mechanisms of this random emission with the continuous spectrum are discussed. The average optical gain coefficient αg at λ = 387 nm in this RL system is estimated, as αg ~ 150 cm-1.
ARTICLE | doi:10.20944/preprints202202.0195.v1
Subject: Chemistry, Applied Chemistry Keywords: olea europaea; olive stone; agro-waste; slow pyrolysis; bimetallic nano-alloys; catalyzed dye degradation; Trash-to-Treasure
Online: 16 February 2022 (06:41:46 CET)
Biochar is a carbon allotrope obtained by pyrolysis of biomass, usually agro-waste. Owing to the demand for sustainable development, biochar is continuously raising much hope in the scientific community. However, in order to impart it with new properties, its modification is required, either in situ during pyrolysis, or after the carbonization process. Herein, we propose a new direct approach to obtain bimetallic copper/nickel nanoparticle-loaded on olive stone biochar. The bimetallic-coated biochar and the reference materials bare biochar, copper-loaded and nickel-loaded biochar were prepared at 400 °C under a stream of dinitrogen from olive pit powder particles impregnated first with citric acid (CA), and then with copper and nickel nitrates. We have employed citric acid in the process in order to check its effect on the structural and textural properties of biochar supporting the metallic nanoparticles. Surprisingly, citric acid induced the formation of agglomerated or even raspberry-shaped, bimetallic copper/nickel nanoparticles. Large 450-500 nm-sized agglomerates of ~80 nm bimetallic CuNi NPs were noted for B-CA@CuNi. Interestingly, for biochar material prepared with initial Cu/Ni=10 molar ratio (B-CA@CuNi10/1), the bimetallic NPs formed unusual nano-raspberries (1748 nm in size) which are agglomerates of individual 10-20 nm-sized CuNi10/1 nanoparticles. The B-CA@CuNi and reference materials were characterized by Raman spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and magnetometry. The B-CA@CuNi and B-CA@Ni materials could be attracted efficiently with a magnet, but not B-CA@CuNi10/1 due to a low nickel loading. B-CA@CuNi was tested as a catalyst for the degradation of methyl orange (MO). Discoloration was noted within 10 min, much faster than a similar material prepared in the absence of CA. B-CA@CuNi could be recycled at least 3 times with exhibit as fast discoloration catalysis performance. This paper stresses the important role of citric acid in shaping the bimetallic nanoparticles loaded in situ on biochar during the slow pyrolysis process and to enable faster catalysed discoloration of organic dye solution.
ARTICLE | doi:10.20944/preprints202112.0295.v1
Subject: Mathematics & Computer Science, Applied Mathematics Keywords: nano-fluid; nanoparticles removing; magnetohydrodynamics; stability of the flow; water treatment; exact solution; instability of the flow
Online: 20 December 2021 (09:37:36 CET)
The process of water treatment by nanoparticles is one of the most considerable subjects in the cross-field of hydrodynamics, chemistry and mathematics. This paper is dedicated to the case of the flows that appear when squeezing and stretching a spongy with a mix of water with nanoparticles and contaminants. It is assumed that fluid is homogeneous at the starting moment, the parameters of the nanoparticles and contaminants are known, and there is a constant non-homogeneous magnetic field applied to the system. The flow starts moving when the walls of the channel shift to each other. Exact and numerical solutions of the system of ordinary differential equations are used to receive the results. The article gives an answer to the question about stability of the flow and proposes the technique to evaluate the essential characteristics of the system to achieve the treatment process efficiency. The main result is that the considered system shows excellent treatment properties during some part of squeezing stage. This effect does not appear without magnetic field.
ARTICLE | doi:10.20944/preprints202003.0154.v1
Subject: Materials Science, General Materials Science Keywords: eutectic high-entropy alloy; dynamic shear deformation; split-Hopkinson pressure bar test; hat-shaped specimen; nano-indentation
Online: 10 March 2020 (03:09:01 CET)
Lamellar eutectic structure of Al0.7CoCrFeNi high-entropy alloy (HEA) is emerging as a promising candidate for structural applications because of its high strength-ductility combination. The alloy consists of a fine-scale lamellar fcc+B2 microstructure with high flow stresses >1500 MPa under quasi-static conditions. The response to shear loading was not investigated so far. This is the first report on the shear deformation of an eutectic structured HEA and effect of precipitation on shear deformation. The dynamic shear response (DSR) of the eutectic HEA was examined in two microstructural conditions, with and without the presence of L12 precipitates. A split-Hopkinson pressure bar (SHPB) was used to compress the hat-shaped specimens to study the local DSR of the alloy. The adiabatic shear bands (ASBs) in two different microstructural conditions were characterized after deformation at dynamic strain rates. The adiabatic shear localization occurs at low strains for the high strength material, and the eutectic microstructure does not delay cracking. The width of ASBs and the extent of plastic deformation around them has been correlated with the rate of straining. Dynamic recrystallization within ASBs and profuse twinning around it was observed. Local mechanical response of individual lamellae before and after shear deformation was examined using nano-indentation.
ARTICLE | doi:10.20944/preprints201806.0478.v1
Subject: Earth Sciences, Environmental Sciences Keywords: allophane; adsorption; precipitation; interface processes; environment; heavy metals; nano-structure; short-range order aluminosilicate; wastewater treatment; aqueous geochemistry
Online: 28 June 2018 (15:39:12 CEST)
The capacity and the mechanism of the adsorption of aqueous barium (Ba), cobalt (Co), strontium (Sr) and zinc (Zn) by Ecuadorian (NatAllo) and synthetic (SynAllo-1 and SynAllo-2) allophanes were studied as a function of contact time, pH and metal ion concentration using kinetic and equilibrium experiments. The mineralogy, nano-structure and chemical composition of the allophanes were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and specific surface area analyses. The evolution of adsorption fitted to a pseudo-first-order reaction kinetics, where equilibrium between aqueous metal ions and allophane was reached within < 10 min. The metal ion removal efficiencies varied from 0.7 to 99.7 % at pH 4.0 to 8.5. At equilibrium, the adsorption behavior is better described by the Langmuir model than by the Dubinin-Radushkevich model, yielding sorption capacities of 10.6, 17.2 and 38.6 mg/g for Ba^(2+), 12.4, 19.3 and 29.0 mg/g for HCoO_2^-, 7.2, 15.9 and 34.4 mg/g for Sr^(2+) and 20.9, 26.9 and 36.9 mg/g for Zn^(2+), respectively, by NatAllo, SynAllo-2 and SynAllo-1. The uptake mechanism is based on a physical adsorption process. Allophane holds great potential to remove aqueous metal ions and could be used instead of zeolites, montmorillonite, carbonates and phosphates for wastewater treatment.
REVIEW | doi:10.20944/preprints202011.0156.v1
Subject: Materials Science, Nanotechnology Keywords: Bacterial detection; Biosensors; Clinical pathogen; COVID-19; Electrospun nanofibers; Nano-biosensors; Point-of-care; SARS-CoV-2; Viral detection.
Online: 3 November 2020 (14:15:34 CET)
Biosensors are measurement devices that can sense several biomolecules, and are widely used for the detection of relevant clinical pathogens such as bacteria and viruses, showing outstanding results. Because of the latent existing risk of facing another pandemic like the one we are living due to COVID-19, researchers are constantly looking forward to developing new technologies for diagnosis and treatment of infections caused by different bacteria and viruses. Regarding that, nanotechnology has improved biosensors design and performance through the development of materials and nanoparticles that enhance their affinity, selectivity, and efficacy in detecting these pathogens, such as employing nanoparticles, graphene quantum dots, and electrospun nanofibers. Therefore, this work aims to present a comprehensive review that exposes how biosensors work in terms of bacterial and viral detection, and the nanotechnological features that are contributing to achieving a faster yet still efficient COVID-19 diagnosis at the point-of-care.
ARTICLE | doi:10.20944/preprints201812.0119.v1
Subject: Physical Sciences, Applied Physics Keywords: 3D nano-lithography, 3D laser lithography, direct laser writing, nanopolymerization, cross-linking, multi-photon absorption, avalanche ionization, temperature effects
Online: 11 December 2018 (09:31:31 CET)
Direct laser writing three-dimensional nano-lithography is an established technique for manufacturing functional 3D micro- and nano-objects via non-linear absorption induced polymerization process. In this Chapter an underlying physical mechanisms taking place during nano-confined polymerization reaction, induced by tightly focused ultra-short laser pulses, are reviewed and discussed. The special attention is paid on the effects that directly impact structuring resolution and minimum achievable feature size. Analysis of possible photo-initiation mechanisms as contributing multi-photon absorption and avalanche ionization in pre-polymers under diverse exposure conditions (wavelength, pulse duration) is presented. Feasible structuring of pure (non-photosensitized) and functional nanoparticles doped polymer precursors is justified and benefits of such materials/structures for microoptics, photonics and cell scaffolds are highlighted. The influence of temperature effects (induced by writing process itself or determined by ambient conditions) on polymerization process, observed in different pre-polymers under diverse exposure regimes is outlined. The further adjustment of the structuring resolution is possible via precise control of light polarization and diffusion assisted radical quenching. The work is concluded with a brief outlook on future challenges and perspectives related to refinement of 3D ultra-fast laser lithography fabrication process in the means of application of diverse post-processing methods and research into novel photo-curable materials including inorganic ones.
ARTICLE | doi:10.20944/preprints201809.0003.v1
Subject: Chemistry, Analytical Chemistry Keywords: surface plasmon resonance; urinary tract infection; surface relief gratings; crossed surface relief gratings; nano-plasmonics; biosensing; uropathogenic E. coli
Online: 1 September 2018 (17:29:04 CEST)
Given the rise in the number of cases and their recurrences, Urinary Tract Infections (UTI) are one of the major burdens on public healthcare worldwide. Rapid, inexpensive and selective detection of Uropathogenic E. coli (UPEC), a major contributor to UTIs, is the need of the hour for effective treatment, given the rise of antibiotic-resistant bacteria due to improper diagnosis. Here we present a rapid, real-time, selective and label-free detection of UPEC using an integrated sensing platform based on Crossed Surface Relief Gratings (CSRGs) as nanoplasmonic sensors. Detection is achieved due to the unique Surface Plasmon Resonance (SPR)-based light energy exchange attributed to the CSRGs, allowing real-time sensing in a very narrow bandwidth of the incident light to pass where the SPR energy conversion occurs. The sensing ability of the platform is experimentally demonstrated by the detection of bulk Refractive Index (RI) changes, with a bulk sensitivity of 382.2 nm/RIU and a resolution in the order of 10-6 RIU. We demonstrate selective capture and detection of clinical concentration of UPEC, as opposed to other gram-negative bacteria, in real-time, a first for CSRGs. This work is particularly important for effective treatment of UTIs, allowing point-of-care diagnosis for economically disadvantaged regions around the world.
CONCEPT PAPER | doi:10.20944/preprints202102.0228.v1
Subject: Materials Science, Biomaterials Keywords: energetic materials; solid propulsion systems; extreme thrust control; reaction zones; functionalized carbon-based nanostructured metamaterials; nano-sized additives; carbon atomic wires, sp1-hybridized bonds; ion-assisted pulsed-plasma deposition; self-organizing of the nanostructures; universal phenomena of nano-cymatics; electrostatic field; synergistic effect
Online: 9 February 2021 (09:48:42 CET)
A new generation of nano-technologies is expanding solid propulsion capabilities and increasing their relevance for versatile and manoeuvrable micro-satellites with safe high-performance propulsion. We propose the innovative concept, connected with application of new synergistic effect of the energetic materials performance enhancement and reaction zones programming for the next generation small satellite multimode solid propulsion system. The main idea of suggested concept is manipulating by the self-organized wave patterns excitation phenomenon, by the properties of the energetic materials reaction zones and by localization of the energy release areas. This synergistic effect can be provided through application of the functionalized carbon-based nanostructured metamaterials as a nano-additives along with simultaneous manipulating by their properties through the electrostatic field. Mentioned effect will be controlled through predictive programming both by the spatial structure and physics-chemical properties of the functionalized carbon-based nano-additives and through the electromagnetic control of the self-organized wave pattern excitation and micro- and nano- scale oscillatory networks in the energetic material reaction zones. Suggested new concept makes it possible to increase the energetic material regression rate and increase the thrust of the solid propulsion system with minimal additional energy consumption.
ARTICLE | doi:10.20944/preprints202010.0525.v1
Subject: Materials Science, Biomaterials Keywords: Ni-P-MoS2-SiO2 nano-composite coatings; Ni-P-MoS2 composite coatings; Ni-P-Toner composite coatings; Electrochemical properties; Electroless
Online: 26 October 2020 (13:56:19 CET)
In this paper, various Ni-P composite coatings containing toner, MoS2, and nano-SiO2 particles were deposited on steel substrates by the electroless method. Then, the electrochemical properties of these coatings after a heat treatment process were compared. The microstructural evaluations were also done by using the optical and electron microscopy methods. Both Tafel polarization and electrochemical impedance spectroscopy techniques were utilized to survey the electrochemical behavior of such coatings. The surface morphology of all coatings contained cauliflower-like nodules. The X-ray diffraction patterns showed the crystalline phases of Ni and Ni3P for all coatings after the heat-treatment step. Obtained results showed that all composite coatings exhibited lower corrosion rates with respect to Ni-P coatings. Such a reduction was about 21.6-92.2%. This behavior was attributed to the presence of reinforcement as barriers for corrosive ion diffusion through the coating plus the changes in detected phases and thickness. Electrochemical impedance spectroscopy test results also demonstrated that the increase in the polarization resistance for composites coatings was about 18.4-85.3% after 1 h immersion in a 0.6M NaCl solution; however, when the immersion time increased to 24 h, such increased resistance changed to 18.1 to 73.1%. Totally, despite the lower deposition rate, the presence of MoS2 and nano-SiO2 particles were more effective than toner particles to raise the corrosion rate of the Ni-P coating.
ARTICLE | doi:10.20944/preprints202007.0625.v1
Subject: Engineering, General Engineering Keywords: elderly care; hand gesture; computer vision system; Microsoft Kinect depth sensor; Arduino Nano Microcontroller; global system for mobile communication (GSM)
Online: 26 July 2020 (02:07:09 CEST)
Hand gestures may play an important role in medical applications for health care of elderly people, where providing a natural interaction for different requests can be executed by making specific gestures. In this study we explored three different scenarios using a Microsoft Kinect V2 depth sensor then evaluated the effectiveness of the outcomes. The first scenario utilized the default system embedded in the Kinect V2 sensor, which depth metadata gives 11 parameters related to the tracked body with five gestures for each hand. The second scenario used joint tracking provided by Kinect depth metadata and depth threshold together to enhance hand segmentation and efficiently recognize the number of fingers extended. The third scenario used a simple convolutional neural network with joint tracking by depth metadata to recognize five categories of gestures. In this study, deaf-mute elderly people execute five different hand gestures to indicate a specific request, such as needing water, meal, toilet, help and medicine. Then, the requests were sent to the care provider’s smartphone because elderly people could not execute any activity independently. The system transferred these requests as a message through the global system for mobile communication (GSM) using a microcontroller.
REVIEW | doi:10.20944/preprints201810.0204.v2
Subject: Life Sciences, Biotechnology Keywords: DNA origami; aptamer; DNA nanotechnology; protein nano array; biosensor; logic gate; enzyme cascade; drug delivery system; targeted therapy; molecular robotics
Online: 22 October 2018 (10:57:21 CEST)
DNA origami has emerged in recent years as a powerful technique for designing and building 2D and 3D nanostructures. While the breadth of structures that have been produced is impressive, one of the remaining challenges, especially for DNA origami structures intended to carry out useful biomedical tasks in vivo, is to endow them with the ability to detect and respond to molecules of interest. Target molecules may be disease indicators or cell surface receptors, and the responses may include conformational changes leading to release of therapeutically relevant cargo. Nucleic acid aptamers are ideally suited to this task and are beginning to be used in DNA origami designs. In this review we consider examples of uses of DNA aptamers in DNA origami structures and summarise what is currently understood regarding aptamer-origami integration. We review three major roles for aptamers in such applications: protein immobilisation, triggering of structural transformation, and cell targeting. Finally, we consider future perspectives for DNA aptamer integration with DNA origami.
REVIEW | doi:10.20944/preprints202011.0061.v1
Subject: Biology, Anatomy & Morphology Keywords: Targeted Protein Silencing (TPS); Targeted Protein Degradation (TPD); dTAG; FKBP12; von Hippel-Lindau (VHL); degron; deGradFP; Anchor-Away; Nanobody; Nano-Grad
Online: 2 November 2020 (15:59:46 CET)
Targeted Protein Silencing (TPS) is an elegant approach to investigate protein function and its role in the cellular landscape, overcoming limitations of genetic perturbation strategies. In contrast to CRISPR/Cas9 and RNA interference, these systems act in a reversible manner and reduce off-target effects. Several TPS have been developed and wisely improved, including compartment delocalization tools and protein degradation systems. In this review, we focus on Anchor-Away, deGradFP, auxin inducible degron (AID) and dTAG technologies, and discuss their recent applications and advances. Finally, we propose Nano-Grad, a novel nanobody-based protein degradation tool to specifically proteolyze endogenous tag-free target protein.
COMMUNICATION | doi:10.20944/preprints202007.0443.v1
Subject: Materials Science, Nanotechnology Keywords: Coronavirus disease 2019; COVID-19 pandemic; HIV/AIDS; Nanoantivirals; Smart nanomaterials; Synergistic oxidant @ reductant agents, antiviral coatings; Oxidizer and Reductant Nano agents; Nanomedicine
Online: 19 July 2020 (20:56:28 CEST)
Research on the chemical mechanism and reciprocal behavior of the coronavirus relate to living organisms, engaging in the give and take of electrochemical mediators, is a very important, controversial and vital issue. What we should accept is the chemical identity of this scenario, and not preferably a characteristic of a biological system. This chemical reaction should be familiar, referring to the theory of chemical pathways involved in DNA/proteins in the body against aggressive guests (such as viruses). From the point of view of a chemist, this simple reaction is nothing more than an oxidation-reduction reaction (redox-stress signaling) which conducted and carried out by coronavirus in a biointerface medium. Thereby, oxidizing as well as reducing reagents should be very constructive, promoting development in such chemical process. We understand redox reactions as switchable thiol/disulfide exchanges (formation and cleavage of inherent disulfide bonds), then, we can hugely profit from redox-responsive nano-surfaces equipped with multiple new ionic and covalent interactions. This game-changing idea can substantiate by surface modified-nanoparticles to play powerful roles in synthesis of nano oxidizers as well as reducing agents in nanomedicine. Chemists and pharmacists must then explore new thoughts and present modern experiences/approaches of preparation nanoparticles and nanocomposites to create novel vaccines as well as coronavirus drugs. In this regard, this experience can also be so helpful for HIV/AIDS, which is caused by viruses.
ARTICLE | doi:10.20944/preprints201905.0006.v1
Subject: Engineering, Mechanical Engineering Keywords: Biopolymers; Nanoclays; Nano-biocomposites; Extrusion-compounding; Poly(hydroxyalkanoates); Thermal properties; Microstructure; Volatiles; Autoxidation, Thermal gravimetric analysis, Scanning electron microscope, Headspace-solid phase microextraction.
Online: 3 May 2019 (15:11:39 CEST)
Poly(hydroxyalkanoates) (PHAs) are currently considered competent candidates to replace traditional plastics in several market sectors. However, commercial PHA grades exhibit unsatisfactory smell that can negatively affect the quality of the final product. The cause of this typical rancid odour is attributed to oxidized cell membrane glycolipids, coming from Gram negative production strains, which remain frequently attached to PHAs granules after extraction. The aim of this research is the development of customised PHA nano-biocomposites for industrial applications containing organo-modified nanoclays with high adsorption properties able to capture volatile compounds responsible of the displeasing fragrance in PHAs. To this end, a methodology for the detection and identification of the key volatiles released due to oxidative degradation of PHAs has been established using a headspace solid-phase microextraction technique. We report the development of nine nano-biocomposite materials based on three types of commercial PHA matrices loaded with three species of nanoclays which represent a different polar behaviour. It has been demonstrated that although the reached outcome effect depends on the volatile nature, natural sepiolite (T2) might result in the most versatile candidate for all PHA matrices selected.
ARTICLE | doi:10.20944/preprints201810.0386.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: physical vapor deposition; magnetron-sputtering; AlN/Al coating; silicon substrate; residual stresses; wafer curvature method; Nano-scale residual stress profiling; indentation failure modes; nanoindentation adhesion
Online: 17 October 2018 (12:36:39 CEST)
Compressive residual stresses in thin films can inhibit crack propagation under normal or sliding contact loading, with associated enhancement of the coating apparent toughness, load bearing capacity and wear resistance. This study investigates the influence of residual stress distributions on the thin film/substrate adhesion using a nanoindenter coupled with scanning electron microscope (SEM) investigations of indentation induced failure modes. Reactive and un-reactive magnetron sputtering with ion plating was used to coat a (100) silicon substrate with aluminum nitride (AlN) with and without an aluminum (Al) adhesion layer. The presence of an Al bond layer gives additional interfacial tensile stress because of the difference in thermal expansion coefficient. Additionally, a different magnitude of residual stresses in the AlN coating was achieved by changing the applied bias voltage onto the substrate. Wafer curvature method and incremental focused ion beam (FIB) milling, combined with high-resolution in situ scanning electron microscopy (SEM) imaging and full field strain analysis by digital image correlation (DIC), were used to measure the average and in-depth stress residual stress distribution in the produced coatings. The adhesion energy was then quantified by using a nanoindentation based model. Results demonstrate that the additional tensile residual stress in the aluminum adhesion layer decrease significantly the coating adhesion, even in presence of a higher compressive stress state in the AlN top-layer. Therefore, the coatings without Al-layer showed better adhesion because of a more homogeneous compressive residual stress in comparison with the coating having Al layer, even though both groups of coatings are produced under same bias voltage. Results are discussed, and some general suggestions are made on the correlation between coating/substrate property combination and the adhesion energy of multilayer stacks. The results suggested that Al bond-layer and inhomogeneous residual stresses affected the adhesion of AlN negatively to a substrate like silicon.
ARTICLE | doi:10.20944/preprints202107.0627.v2
Subject: Engineering, Civil Engineering Keywords: nanotechnology in pavement engineering; stabilisations of naturally available materials; road pavement engineering; mineralogy; chemistry in emulsions; organofunctional silanes; anionic emulsion; cationic emulsion; New-age (Nano) Modified Emulsions (NME)
Online: 14 September 2021 (15:20:44 CEST)
Nano-scale organofunctional silanes have been developed, tested and successfully applied to protect stone buildings in Europe against climatic effects since the 1860s. The same nanotechnologies can also be used in pavement engineering to create strong chemical bonds between a stabilising agent and the material substrata. The attachment of the organofunctional silane to a material also makes the surface of the material hydrophobic, reducing future chemical weathering. These properties allow naturally available materials to be used in any pavement layer at a low risk. In the built environment, scientists soon determined that the successful use of an organo-silane depends on the type and condition of the stone to be treated. The same principles apply to the implementation of applicable nanotechnologies in pavement engineering. Understanding the basic chemistry determining the properties of the stabilising agent and the organofunctional modifying agent and the chemical interaction with the primary and secondary minerals of the material are essential for the successful application of these technologies in pavement engineering. This paper explains some basic chemistry which fundamentally influences engineering outputs that can be achieved using New-age (Nano) Modified Emulsions (NME) stabilising agents with naturally available material in all road pavement TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back
CONCEPT PAPER | doi:10.20944/preprints202103.0350.v1
Subject: Materials Science, Biomaterials Keywords: carbyne-enriched nanostructured metamaterials; sp1-hybridized bonds; carbon atomic wires; ion-assisted pulsed-plasma deposition; nanocavities; cluster-assembling; vibration-assisted growing; acoustic activation; vibrational patterns; electromagnetic activation; self-organizing of the nanostructures; nano-cymatics; controlled patterning; synergistic effect
Online: 12 March 2021 (20:07:52 CET)
Structural self-organizing and pattern formation are universal and key phenomena observed during growth and cluster-assembling of the carbyne-enriched nanostructured metamaterials at the ion-assisted pulse-plasma deposition. Fine tuning these universal phenomena opens access to designing the properties of the growing carbyne-enriched nano-matrix. The structure of bonds in the grown carbyne-enriched nano-matrices can be programmed by the processes of self-organization and auto-synchronization of nanostructures. We propose the innovative concept, connected with application of the universal Cymatics phenomena during the predictive growth of the carbyne-enriched nanostructured metamaterials. We also propose the self-organization approach for increase stability of the long linear carbon chains. The main idea of suggested concept is manipulating by the self-organized wave patterns excitation phenomenon and their distribution by the spatial structure and properties of the nanostructured metamaterial grows region through the new synergistic effect. Mentioned effect will be provided through the vibration-assisted self-organized wave patterns excitation along with simultaneous manipulating by their properties through the electric field. We propose to use acoustic activation of the plasma zone of nano-matrix growing. Interaction between the inhomogeneous electric field distribution generated on the vibrating layer and the plasma ions will serve as the additional energizing factor controlling the local pattern formation and self-organizing of the nano-structures. Suggested concept makes it possible to provide precise predictive designing the spatial structure and properties of the advanced carbyne-enriched nanostructured metamaterials.
ARTICLE | doi:10.20944/preprints202101.0589.v1
Subject: Engineering, Civil Engineering Keywords: nanotechnology in pavement engineering; thin surfacings for New-age (Nano) Modified Emulsion stabilised base layers; applicable modified binders for chip seals; Cape seals using anionic New-age Modified Emulsion slurries; Sasobit-M® modified binders for chip seals.
Online: 28 January 2021 (15:35:30 CET)
Emulsion stabilisation of base layers surfaced with chip seals often proves problematic with chips punching into the base and early distress. This can be aggravated by the use of modified binders that restricts the evaporation of moisture from pavement layers. The introduction of New-age (Nano) Modified Emulsion (NME) stabilisation has the advantage that water is chemically repelled from the stabilised layer resulting in an accelerated development of strength. A need was identified to evaluate the early life performance of selected chip seals, together with identified binders. Three different chip seal surfacings with unconventional modified binders were constructed and evaluated using Accelerated Pavement Testing (APT) with the MMLS3. The objectives of the experimental design and testing were to evaluate binder performance, early loss of chips before chip orientation at low temperatures, punching of the chips into the NME stabilised base, deformation characteristics of a Cape seal and the effect of the use of a standard normal modified binder. This paper contains details of the NME base layer, the binder and seal selection and the test results. It is shown that a cost-effective thin chip seal in combination with a suitable binder can be used on a NME stabilised base with confidence.
ARTICLE | doi:10.20944/preprints202108.0425.v1
Subject: Engineering, Civil Engineering Keywords: road pavement design; design based on materials science; material mineralogy; New-age (Nano) Modified Emulsions (NME); naturally available materials; material stabilisation; basic engineering requirements; Unconfined Compressive Strengths (UCS); Indirect Tensile Strengths (ITS); Retained Compressive Strengths (RCT) and; Retained Tensile Strengths (RTS)
Online: 23 August 2021 (10:38:52 CEST)
The use of naturally available materials not conforming to traditional specifications or standards, in the base and sub-base layers of road pavement structures, stabilised with New-age (Nano) Modified Emulsions (NME), have been tested, implemented and successfully verified through Accelerated Pavement Testing (APT) in South Africa. This was made possible through the development and use of a design procedure addressing fundamental principles and based on scientific concepts, which are universally applicable. The understanding of and incorporation of the chemical interaction between the mineralogy of the materials and a NME stabilising agent (compatibility between the chemistry of the reactive agents and material mineralogy) into the design approach is key to achieving the required engineering properties. Stabilised materials evaluation is done using tests indicative of the basic engineering properties (physics) of compressive strengths, tensile strengths and durability. This article describes the basic materials design approach developed to ensure that organofunctional nano-silane modified emulsions can successfully be used for pavement layer construction utilising naturally available materials, at a low risk. The enablement of the use of naturally available materials in all pavement layers can have a considerable impact on the unit cost and life-cycle costs of road transportation infrastructure. TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back
ARTICLE | doi:10.20944/preprints202201.0093.v2
Subject: Engineering, Civil Engineering Keywords: nanotechnology applications in road maintenance; preventative road surface maintenance; nanotechnology clear-seals; New-age (Nano) Modified Emulsions (NME); pot-hole repairs; modified binder slurry seals; hydrophobic slurries; hydrophobic road surface sealants; labour intensive maintenance; rapid employment creation through nanotechnology usage in road maintenance
Online: 25 January 2022 (17:34:49 CET)
: Nanotechnology options to road surface maintenance offers several advantages compared to traditionally used materials. The small particle sizer of hydrophobic Nano-Silane modified Nano-Polymers (NSNP) enables these nanotechnology products to deeply penetrate existing road surfaces, sealing micro-cracks and render surfacings to be water-resistant for extended periods of time. In comparison, traditionally used products contain minimum partial sizes of about 1 – 5 microns, that provide a superficial protection that wears off in a relatively short period of time. These traditional products are often associated with vehicle contamination while drying and requires the re-instatement of road markings. None of these disadvantages are associated with applicable NSNP technologies that are quick drying, with no vehicle contamination risks and is equivalent to a “clear-seal” requiring no reinstatement of road markings. In a similar vein, pot-hole repairs can be done using applicable, easy to use, pre-packed and treated pot-hole repair kits that are water-repellent and quick-drying at a fraction of the costs of conventional cold-mix products. Resurfacing using NME binder slurries can be done labour-intensively on a pre-treated NSNP surfacing, restoring cracked surfacing and providing a water-resistant long-lasting protective layer without the removal of existing cracked areas. The implementation of nanotechnology solutions for road surface maintenance operations is directly associated with ease of use, labour-intensive operations, prevention of considerable deterioration in riding quality due to removal and manual re-instatement of cracked surfaces, time and cost savings and a reduction in the risk of water damage to the sub-structure. TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back TRANSLATE with x English ArabicHebrewPolish BulgarianHindiPortuguese CatalanHmong DawRomanian Chinese SimplifiedHungarianRussian Chinese TraditionalIndonesianSlovak CzechItalianSlovenian DanishJapaneseSpanish DutchKlingonSwedish EnglishKoreanThai EstonianLatvianTurkish FinnishLithuanianUkrainian FrenchMalayUrdu GermanMalteseVietnamese GreekNorwegianWelsh Haitian CreolePersian TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back
ARTICLE | doi:10.20944/preprints201802.0163.v1
Subject: Physical Sciences, Optics Keywords: optical metamaterials; fundamental concepts in photonics; light-matter interactions at the subwavelength and nanoscale; fundamental understanding of linear and nonlinear optical processes in novel metamaterials underpinning photonic devices and components; advancing the frontier of nanophotonics with the associated nanoscience and nanotechnology; nanostructures that can serve as building blocks for nano-optical systems; use of nanotechnology in photonics; nonlinear nanophotonics, plasmonics and excitonics; subwavelength components and negative index materials; slowing, store, and processing light pulses; materials with such capabilities that could be used for optical sensing, tunable optical delay lines, optical buffers, high extinction optical switches, novel image processing hardware, and highly-efficient wavelength converters
Online: 26 February 2018 (11:24:39 CET)
Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described which enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular properties of the outlined processes in the proposed metamaterial are demonstrated through numerical simulations. Potential applications include ultra-miniature amplifiers, frequency changing reflectors, modulators, pulse shapers, and remotely actuated sensors.