ARTICLE | doi:10.20944/preprints202203.0008.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: Sustainable dryland farming; clay soil amendment; soil water use; organic matter; enzyme activity; nutrient turnover
Online: 1 March 2022 (08:27:33 CET)
Degraded soils causing from natural and human affects are universal in arid and semi-arid regions all over the world. Bentonite and humic acid (BHA) are increasingly being tested to remediate these degraded lands with potential benefits on crop production and soil health. The objective of this paper was to determine the residual effects four to five years after a one-time BHA application at six rates on (i) dynamic changes in soil properties, and (ii) oat crop productivity parameters, in a dryland farming ecosystem. With increasing rates of one-time BHA application, soil profile water storage displayed a piecewise linear increase plus plateau, whereas soil electrical conductivity, pH and bulk density were all reduced significantly (P < 0.05) in the 0-20 cm and 20-60 cm layers. The improved soil environments gave rise to an increased activity of soil enzymes urease, invertase and catalase that respectively reached the peak values of 97%, 37% and 32% at the rates of 21 to 24 Mg BHA ha-1. These conversely boosted soil nutrient turnover, leading to a 40% higher soil available P. Compared with the control treatment, application of BHA at the estimated optimum rate (roughly 24 Mg ha-1) increased grain yield by 20%, protein yield by 62%, water use efficiency by 41%, and partial factor productivity of N by 20%. Results of this study showed for the first time that a one-time BHA application would be a new and effective strategy to combat land degradation, drought, and promote a sustainable soil micro-ecological environment in dryland agroecosystem under a varying climate scenario.
ARTICLE | doi:10.20944/preprints202208.0264.v1
Subject: Earth Sciences, Geophysics Keywords: airborne gamma-ray spectroscopy; non-linear machine learning; potassium; clay; thorium; sand; soil texture; paleo-hydrography
Online: 15 August 2022 (12:01:44 CEST)
Soil texture is key information in agriculture for improving soil knowledge and crop performance, so the accurate mapping of this crucial feature is imperative for rationally planning cultivations and for targeting interventions. We studied the relationship between radioelements and soil texture in the Mezzano Lowland (Italy), a 189 km2 agricultural plain investigated through a dedicated airborne gamma-ray spectroscopy survey. The K and Th abundances were used to retrieve the clay and sand content by means of a multi-approach method. Linear (simple and multiple) and non-linear (machine learning algorithms with deep neural networks) predictive models were trained and tested adopting a 1:50,000 scale soil texture map. The comparison of these approaches highlighted that the non-linear model introduces significant improvements in the prediction of soil texture fractions. The predicted maps of the clay and of the sand content were compared with the regional soil maps. Although the macro-structures were equally present, the airborne gamma-ray data permits us shedding light on finer features. Map areas with higher clay content were coincident with paleo-channels crossing the Mezzano Lowland in Etruscan and Roman periods, confirmed by the hydrographic setting of historical maps and by the geo-morphological features of the study area.
ARTICLE | doi:10.20944/preprints201809.0343.v1
Subject: Engineering, Civil Engineering Keywords: initial water content; lean clay soil; compound calcium-based stabilizer; compressibility; strength; microstructure and composition
Online: 18 September 2018 (10:39:53 CEST)
Initial water content significantly affects the efficiency of soil stabilization. In this study, the effects of initial water content on the compressibility, strength, microstructure and composition of a lean clay soil stabilized by compound calcium-based stabilizer were investigated by static compaction test, unconfined compression test, optical microscope observations, environment scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction spectroscopy. The results indicate that as the initial water content increases in the range studied, both the compaction energy and the maximum compaction force decrease linearly and there are less soil aggregates or agglomerations, and smaller proportion of large pores in the compacted mixture structure. In addition, for specimens cured with or without external water supply and under different compaction degrees, the variation law of the unconfined compressive strength with initial water content is different and the highest strength value is obtained at various initial water contents. With the increase of initial water content, the percentage of oxygen element tends to increase in the reaction products of the calcium-based stabilizer, whereas the crystalline mineral of the soil did not change obviously.
ARTICLE | doi:10.20944/preprints202208.0216.v1
Subject: Earth Sciences, Geoinformatics Keywords: block cokriging; clay composition; granulometry; multi-collocated cokriging; multi-collocated fac-torial cokriging; regularization; SIDSAM; VIS-NIR-SWIR spectroscopy
Online: 11 August 2022 (11:30:23 CEST)
Traditional soil characterization methods are time consuming, laborious and invasive and do not allow long-term repeatability of measurements. The overall aim of this paper was to assess and model spatial variability of the soil in an olive grove in south Italy by using data from two sensors of different type: a multi-spectral on-board drone radiometer and a hyperspectral visible-near infrared-shortwave infrared (VIS-NIR-SWIR) reflectance radiometer as well as sample data, to arrive at a delineation of homogeneous areas. The hyperspectral data were processed using continuum removal methodology to obtain information about the content and composition of clay. Differently, the multispectral data were firstly upscaled to the support of soil data using geostatistics and taking into account change of support. Secondly, the two-sensor data were integrated with soil granulometric properties by using the multivariate geostatistical techniques of multi-collocated cokriging and factor cokriging, in order to achieve a more exhaustive and finer-scale soil characterisation. The paper shows the impact of change of support on the uncertainty of soil prediction that can have a significant effect on decision making in Precision Agriculture. Moreover, four regionalised factors at two different scales (two per each scale) were retained and mapped. Each factor provided a different delineation of the field with areas characterised by different granulometry and clay composition. The applied method is sufficiently flexible and could be applied to any number and type of sensors.
ARTICLE | doi:10.20944/preprints201808.0128.v2
Subject: Chemistry, Physical Chemistry Keywords: bentonite, N2 physisorption, BET, thermogravimetry, clay
Online: 10 August 2018 (09:51:31 CEST)
The employment of clays in industry and on laboratory scale is still of interest, despite their long history. The chemical-physical characteristics of such material are strongly related to their geographical origin and the availability of proper characterization techniques is of great importance in order to gain as more information about their behavior when utilized as filling materials. In the present contribute a physical characterization by meaning of Thermogravimetry and N2 physisorption, including a thermal stability evaluation, of samples of Sardinian bentonite collected from the Alghero area (Italy) is reported.
REVIEW | doi:10.20944/preprints202008.0240.v1
Subject: Earth Sciences, Geology Keywords: clay minerals; heterogeneous catalysis; saponite; synthesis; urea
Online: 10 August 2020 (06:29:57 CEST)
Clay minerals surfaces potentially played a role in prebiotic synthesis through adsorption of organic monomers that give rise to highly concentrated systems; facilitate condensation and polymerization reactions; protection of early biomolecules from hydrolysis and photolysis; and surface-templating for specific adsorption and synthesis of organic molecules. This review presents processes of clay formation using saponite as a model clay mineral since it is shown to catalyze organic reactions, easy to synthesize in large and pure form, and has tunable properties. In particular, a method involving urea is presented as a reasonable analog of natural processes. The method involves a two-step process – 1) formation of the precursor aluminosilicate gel and 2) hydrolysis of a divalent metal (Mg, Ni, Co, Zn) by the slow release of ammonia from urea decomposition. The aluminosilicate gels in the first step forms a 4-fold-coordinated Al3+ similar to what is found in nature such as in volcanic glass. The use of urea, a compound figuring in many prebiotic model reactions, circumvents the formation of undesirable brucite, Mg(OH)2, in the final product by slowly releasing ammonia thereby controlling the hydrolysis of magnesium. In addition, the substitution of B and Ga for Si and Al in saponite is also described The saponite products from this urea-assisted synthesis were tested as catalysts for several organic reactions including Friedel-Crafts alkylation, cracking and isomerization reactions.
ARTICLE | doi:10.20944/preprints201705.0112.v1
Subject: Chemistry, Physical Chemistry Keywords: adsorption; magadiite; cationic clay; methylene blue; remediation
Online: 15 May 2017 (12:14:05 CEST)
The removal of methylene blue (MB) dye from water was investigated using synthetic nano-clay magadiite (SNCM). SNCM was synthesized by hydrothermal treatment under autogenous pressure. A rosette-shaped single mesoporous magadiite phase with 16.63 nm average crystallite size and 33 m2.g-1 BET-surface area was recorded. The adsorption results indicated the pronounced affinity of the SNCM to the MB dye molecules which reached adsorption uptake of 20.0 mg MB dye/g of SNCM. The elimination of MB dye by the SNCM was kinetically and thermodynamically considered; a pseudo second order kinetic model was attained, and a spontaneous, chemical, and exothermic in nature was verified.
ARTICLE | doi:10.20944/preprints202208.0018.v1
Subject: Engineering, Civil Engineering Keywords: atterberg limits; fallcone; Casagrande; flow index; clay mineralogy.
Online: 1 August 2022 (10:06:51 CEST)
In geotechnical engineering applications, it is very important to obtain the undrained shear strength of remolded soils accurately and reliably. This study aims to obtain a trustworthy solution to determine the undrained shear strength of remolded clay mixtures using Atterberg limit test results in various states of consistency. An experimental study was carried out involving a wide range of clay mixtures of varying plasticity and geological origin. In the analyses, the variation of the remolded undrained shear strength depending on the cone penetration depth, water content, flow index, liquidity index and log liquidity index were investigated. In the study, the highest undrained shear strength of 100% Na-montmorillonite (NaM) was obtained at 171.89 kPa at 56.60% water content, while the lowest undrained shear strength was obtained for 100% Sepiolite (S), 9.28 kPa at 31.65% water content. The results of this study revealed that the shear strength is significantly affected by soil conditions, rather than dominant clay mineral. Besides, it was observed that the undrained shear strength at the plastic limit was approximately 30-35 times greater than that at liquid limit. The equations of liquid limit-flow index and plasticity index- flow index were proposed. It was concluded that the interdependence between undrained shear strength, liquidity index, log liquidity index, and flow index is not unique due to the different physical and chemical properties of clays.
ARTICLE | doi:10.20944/preprints202007.0421.v1
Subject: Engineering, Civil Engineering Keywords: strength; stiffness; clay; stabilization; microstructure; wood ash; waste
Online: 19 July 2020 (18:49:54 CEST)
The world’s population is growing at a rapid pace, thus increasing the need for shelter, which, because of increased carbon emissions, is making our planet less inhabitable. Thus, supplementary cementitious materials (SCMs) are used to reduce the embodied carbon emissions in the building sector. Wood ash, as a replacement for cement in soil treatment, seems to be a promising material. In this study, we considered the strength, stiffness, and microstructural behavior of marine clay treated with cement and wood ash as a cement replacement. Since clay is abundant in nature, it could help stabilize waste to improve the mechanical behavior of produced composites. Portland cement (7%, 10%, and 13%) was replaced with various amount of wood ash (5% and 10%) with two different dry densities (1400 and 1600 kg/m3) and three distinct curing periods (7, 28, and 60 days). Unconfined compressive strength, direct shear, porosity, pulse velocity, x-ray diffraction, and scanning electron microscopy tests were performed on selected specimens to evaluate the structural and microstructural effect of clay–wood ash–cement interaction. The results revealed that the replacement of cement with 5% of wood ash yielded superior performance. The microstructure investigation of wood ash–cement–clay blends further showed the formation of a densified matrix with stable bonds. Furthermore, the porosity and strength properties of blends developed unique relationships, which were further confirmed by other supplementary materials and soils.
ARTICLE | doi:10.20944/preprints202105.0630.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: Smart Farm; Smart Systems; Machine Learning; Multispectral Image; Clay.
Online: 26 May 2021 (11:03:37 CEST)
The present work proposed a low-cost portable device as an enabling technology for Smart Farms using multispectral imaging and Machine Learning in soil texture. Clay is an important factor for the verification and monitoring of soil use due to its fast reaction to chemical and surface changes. The system developed uses the analysis of reflectance in wavebands for clay prediction. The selection of each wavelength is performed through an LED lamp panel. A NoIR microcamera controlled by a Raspberry Pi device is employed to acquire the image and unfold it in RGB histograms. Results showed an good prediction performance with R2 of 0.96, RMSEC of 3.66% and RMSECV of 16.87%. The high portability allows the equipment to be used in a field providing strategic information related to soil sciences.
ARTICLE | doi:10.20944/preprints202007.0678.v1
Subject: Engineering, Energy & Fuel Technology Keywords: coal wettability; microemulsion; contact angle; functional group; clay mineral
Online: 28 July 2020 (10:34:51 CEST)
To improve water injection effect, microemulsions (MEs) were used to wet coal seam compared with water and sodium dodecyl sulfate solution (SDS). Wetting effects were characterized by contact angle, X-ray diffraction, Fourier infrared spectroscopy. The results showed that the microemulsion has better spreadability on coal surface and has stronger wettability for coals of different ranks and different particle sizes than traditional wetting agents. The W/O type microemulsion is more affinity to coal than the O/W type and the bicontinuous type.Oxygen and hydrogen contents contributed to wetting. Different wetting agents have the greatest impact on the oxygen-containing functional group absorption zone of coal, but have little impact on the change of clay mineral composition.As the content of quartz increased, the content of montmorillonite was decreased, and the hydrophilicity of coal was increased. This research proposes new ideas for solving coal dust problems and reducing coal mine disasters.
ARTICLE | doi:10.20944/preprints201911.0304.v1
Subject: Materials Science, Other Keywords: Kaolinitic clay; magnesite; slurries; Na silicate; Na hexametaphosphate; rheology
Online: 26 November 2019 (03:37:00 CET)
The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.
ARTICLE | doi:10.20944/preprints201806.0362.v1
Subject: Earth Sciences, Geology Keywords: phyllosilicate minerals; serpentine; chlorite; clay minerals; aggregates; physicomechanical properties
Online: 22 June 2018 (15:38:55 CEST)
This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks from various areas from Greece used as aggregates. The studied lithologies include dunites, harzburgites, lherzolites, gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of studied rock samples was performed by using a Rietveld method on X-Ray diffraction patterns of the studied aggregates. The aggregates are also tested to assign moisture content [w (%)], total porosity [nt (%)], uniaxial compressive strength [UCS (MPa)] and Los Angeles abrasion test [LA (%)]. The influence of secondary phyllosilicate minerals on physicomechanical behavior of tested samples determined using regression analysis and their derived equations. Regression analysis shows positive relationship between the percentage of phyllosilicate minerals of rocks and moisture content as well as with the total porosity values. The relationships between phyllosilicate minerals in the ultramafic and mafic samples and their mechanical properties show that the total rates of phyllosilicate mineral products result negatively in their mechanical properties, while the low percentage of phyllosilicate minerals in volcanic rocks are not able to define set of their engineering parameters.
ARTICLE | doi:10.20944/preprints202205.0371.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Bentonite-Kaolinite-Worm Cast Clay; composite; Diclofenac-Na; geosorption; wastewater
Online: 27 May 2022 (08:48:13 CEST)
Under batch experiment conditions, this work seeks to successfully remove Diclofenac-Na (DCF-Na) from an aqueous solution utilizing a composite sorbent made of Bentonite, Kaolinite clay, and Worm casting (BKW). This study investigated the structural modification of the H3PO4 Modified Clay by X-ray fluorescence and the effect of selected adsorption factors – DCF-Na concentration and modified BKW composite dosage. The concentration equilibrium data was used to study six isotherm models. Freundlich isotherm model better explained the adsorption of DCF-Na onto modified BKW composite with a correlation coefficient close to 1. Kinetics models were examined, and the Elovich model gave a better fit than other kinetic models studied. Mass diffusion mechanisms and thermodynamics studies were successfully carried out. The enthalpy change values evaluated were negative, which revealed the spontaneity of DCF-Na remediation onto modified BKW, and that DCF-Na adsorption is exothermic and occurred through a physisorption process.
ARTICLE | doi:10.20944/preprints201905.0372.v1
Subject: Engineering, Civil Engineering Keywords: Pozzolan; Limestone-Calcined Clay; Fly Ash; Compressive Strength; Hydration Heat
Online: 31 May 2019 (08:14:34 CEST)
This study aims to investigate the hydration and strength characteristics of green cementitious mortars with ultrahigh-volume limestone-calcined clay as well as two kinds of Class F fly ash. Using the ASTM C311 strength activity index test method, the effect of different pozzolan replacement levels of cement (0%, 20%, 50%, and 80%, by weight) were investigated. Compressive strength at 3, 7, 14, 28 and 90 days under standard curing was recorded, and hydration heat of the 20% and 80% replacement mixes was studied using iso-thermal calorimetry. It was observed that the effectiveness of the pozzolan in mortars depends on particle size distribution, glassy or amorphous nature, surface area and replacement level. The sum of all these effects can be captured by the strength activity test only if the standard recommended 20% pozzolan mix is substituted with the actual mix composition. The results in this study provide insights into the mix design and applications of ultrahigh-volume pozzolanic cementitious materials specifically made with limestone-calcined clay, and promote greener cement and concrete in construction industry.
ARTICLE | doi:10.20944/preprints202205.0369.v1
Subject: Earth Sciences, Environmental Sciences Keywords: carbamazepine; adsorption; clay minerals; organoclays; advanced oxidation processes; photocatalysis; water reuse
Online: 27 May 2022 (04:42:22 CEST)
Carbamazepine (CBZ) is one of the most common emerging contaminants released to the aquatic environment through domestic and pharmaceutical wastewater. Due to its high persistence through conventional degradation treatments, is considered a typical indicator for anthropogenic activities. This study tested the removal of CBZ through two different clay-based purification techniques: adsorption of relatively large concentrations (20-500 μmol L-1) and photocatalysis of lower concentrations (<20 μmol L-1). The sorption mechanism was examined by FTIR measurements, exchangeable cations released, and colloidal charge of the adsorbing clay materials. Photocatalysis was performed in batch experiments under various conditions. Despite the neutral charge of carbamazepine, the highest adsorption was observed on negatively charged montmorillonite-based clays. Desorption tests indicate that adsorbed CBZ is not released by washing. The adsorption/desorption processes were confirmed by ATR-FTIR analysis of the clay-CBZ particles. A combination of synthetic montmorillonite or hectorite with low H2O2 concentrations under UVC irradiation exhibits efficient homo-heterogeneous photodegradation at μM CBZ levels. The two techniques presented in this study suggest solutions for both industrial and municipal wastewater, possibly enabling water reuse.
COMMUNICATION | doi:10.20944/preprints202111.0332.v1
Subject: Life Sciences, Biochemistry Keywords: Origins of Life; RNA World; Uracil; Ribosylation; Metal Cation; Clay Mineral
Online: 18 November 2021 (14:35:29 CET)
We report a prebiotically relevant solution to the N1-ribosylation of pyrimidine nucleobases, a well-known challenge in the RNA World hypothesis. It is found that the presence of metal cations and clay mineral enables the previously unachievable direct ribosylation of uracil, providing by far the highest yield. Spectroscopy and chromatography analyses confirmed the formation of ribosylated uracil. The method can also be extended to the ribosylation of 2-pyrimidinone. These findings are also compatible with the metal-doped-clay model developed by our lab for the unified route of the selection of ribose and subsequent syntheses of nucleotide and RNA.
ARTICLE | doi:10.20944/preprints202111.0149.v1
Subject: Chemistry, Applied Chemistry Keywords: Alginate; polyvinyl alcohol; bentonite clay; nanocomposites hydrogel; cationic dyes; water remediation.
Online: 8 November 2021 (14:30:34 CET)
Hazardous chemicals like toxic organic dyes are very harmful to the environment and their removal is quite challenging. Therefore there is a necessity to develop techniques, which are environment friendly, cost-effective and easily available in nature for water purification and re-mediation. The present research work is focused on the development` and characterization of the ecofriendly polyvinyl alcohol (PVA) and alginate (Alg) hydrogel beads incorporating natural bentonite (Bent) clay as beneficial adsorbents for removal of toxic methylene blue (MB) from industrial water. PVA−Alg/Bent nanocomposite hydrogel beads with different Bent content (0, 10, 20, and 30 wt%) were synthesized via external ionic gelation method. The designed porous and steady structure beads were characterized by the use of Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The performance of the beads as MB adsorbents was investigated by treating batch aqueous solutions. The experimental results indicated that the incorporation of Bent (30 w%) in the nanocomposite formulation sustained porous structure, preserved water uptake, and increased MB removal effi-ciency by 230 % compared to empty beads. Designed beads possessed higher aﬃnity to MB at high pH 8, 30 °C, and ﬁtted well to pseudo-second-order kinetic model a high correlation coeﬃcient. Moreover, designed beads had a good stability and reusability as they exhibited excellent removal eﬃciency (90%) after six consecutive adsorption-desorption cycles. Adsorption process was found be combination of both monolayer adsorption on homogeneous surface and multilayer adsorption on heterogeneous surface. The maximum adsorption capacity of the designed beads system as calculated by Langmuir isotherm was found to be 51.34 mg/g, which is in good agreement with the reported clay-related adsorbents. The designed PVA−Alg/Bent nanocomposite hydrogel beads demonstrated good adsorbent properties and could be potentially used for MB removal from polluted water.
ARTICLE | doi:10.20944/preprints202009.0695.v1
Subject: Social Sciences, Other Keywords: clay minerals; limestone; biochar; trace elements; bio-availability; alkaline degraded soils
Online: 28 September 2020 (17:52:02 CEST)
Ca-bentonite (CB) alone and in a mixture with limestone (L), tobacco biochar (TB) and zeolite (Z) on the fixation, geochemical fractions and absorption of Cd and Zn by Chinese cabbage in smelter heavily polluted (S-HP) and smelter low polluted (S-LP) soils were investigated. The results showed that the CB+TB and CB+L+TB treatments significantly immobilized Cd up to 22.03% and 29.68%, respectively, and reduced uptake by Chinese cabbage shoot to 35.98% with CB+Z+L and 61.35% with CB+L in S-HP and S-LP soils compared with the control. The CB+ Z+ L+TB treatment mobilized Cd up to 4.45% and increased absorption in the shoot by 9.85% in S-HP soil. The greatest immobilization of Zn was 53.18% and 58.20% with the CB+Z+L+TB treatment, which reduced Zn uptake in the plant shoot by 9.94% with CB + L and 58.04 with CB+Z+L+TB in S-HP and S-LP soils. The CB+Z+TB and CB+TB treatments mobilized Zn up to 35.40% and 4.80%, respectively, in both soils. Furthermore, the uptake of Zn in plant shoot was observed by 58.96% and 7.82% with application of CB+Z and CB+TB treatments, respectively, in S-HP and S-LP soils. Overall, our results suggest that Ca-bentonite alone and in mixtures with different amendments can be used to reduce the phyto-extraction of Cd and Zn in Zn-smelter polluted soils.
ARTICLE | doi:10.20944/preprints202008.0238.v1
Subject: Engineering, Construction Keywords: autonomous rammed earth construction; red clay; epoxy emulsion; mechanical properties; microstructure
Online: 10 August 2020 (06:21:39 CEST)
Existing rammed earth construction methods have disadvantages such as increased initial costs for manufacturing the large formwork and increased labor costs owing to the labor-intensive construction techniques involved. To address the limitations of existing rammed earth construction methods, an autonomous rammed earth construction method is introduced herein. As this autonomous rammed earth construction method uses a modular formwork, alternative materials must be used in the construction to satisfy the requirements for the early-age binder performance. Accordingly, this study evaluates the use of an epoxy emulsion composed of epoxy and a hardener to enhance the performance of the binder. Preliminary experiments were conducted to determine the optimal formulation of the epoxy emulsion, following which the compressive strength, water loosening, shrinkage, rate of mass change, and microstructure of several red clay binder specimens with and without epoxy emulsion were analyzed at early ages. The results confirmed that the epoxy emulsion can be applied to satisfy the performance requirements for autonomous rammed earth construction by improving the durability and strength of the binder at early ages.
ARTICLE | doi:10.20944/preprints201806.0202.v1
Subject: Engineering, Construction Keywords: marble cutting waste; stabilized clay bricks; hydrated lime; Shaq El-Thoban
Online: 13 June 2018 (05:23:31 CEST)
This study evaluates the feasibility of stabilizing clay bricks with marble cutting waste (MCW). This waste currently discarded in huge quantities as a sludge resulted from sawing the marble blocks to slabs, grinding and polishing of marble processes to the landfills located around the marble processing factories located in the Shaq El-Thoban industrial zone, Cairo governorate, Egypt causing negative impacts on the environment, health and sustainable development. Experimental investigations were carried out to explore the effect of addition of the MCW in different clay-base mixes at different percentages up to 25% at the expense of the hydrated lime. Cement, hydrated lime and MCW are the three types of solidification agents used, clay and sand were also added in the formulations of the unfired clay brick specimens. Laboratory cylindrical stabilized and compressed specimens were made, and then they were cured in a humidity chamber for 2 and 4 weeks, then after were air dried, tested and evaluated according to the Egyptian code for the building by the stabilized and compressed earth soil (ECBS, 2016). To enhance the durability of the cured specimens, transparent silicon – based paint was used for this purpose. The laboratory results demonstrate high potential usage of MCW based additives up to 15% incorporating HL. In addition, the used paint could be an effective treatment way for the use of stabilized bricks in a wet environment. The use of eco-friendly building materials will be a great contribution for the environmental advantages and suggest a remarkable economical alternative to the fired building units.
REVIEW | doi:10.20944/preprints202110.0060.v3
Subject: Biology, Plant Sciences Keywords: RNAi; dsRNA; silencing; encapsulation; liposomes; virus-like particles; polyplex nanoparticles; bio-clay; regulatory
Online: 13 October 2021 (15:39:34 CEST)
RNAi technology is a versatile, effective, safe, and eco-friendly alternative for crop protection. There is plenty of evidence of its use through host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS) techniques to control viruses, bacteria, fungi, insects, and nematodes. For SIGS, its most significant challenge is achieving stability and avoiding premature degradation of RNAi in the environment or during its absorption by the target organism. One alternative is encapsulation in liposomes, virus-like particles, polyplex nanoparticles, and bioclay, which can be obtained through the recombinant production of RNAi in vectors, transgenesis, and micro/nanoencapsulation. The materials must be safe, biodegradable, and stable in multiple chemical environments, favoring the controlled release of RNAi. Most of the current research on encapsulated RNAi focuses primarily on oral delivery to control insects by silencing essential genes. The regulation of RNAi technology focuses on risk assessment using different approaches; however, this technology has positive economic, environmental, and human health implications for its use in agriculture. The emergence of alternatives combining RNAi gene silencing with the induction of resistance in crops by elicitation and metabolic control is expected, as well as multiple silencing and biotechnological optimization of its large-scale production.
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.
Subject: Keywords: clay; mica; biotite; muscovite; origin of life; abiogenesis; mechanical energy; work; wet-dry
Online: 5 November 2020 (10:43:44 CET)
This paper presents a hypothesis about the origins of life in a clay mineral, starting with the earliest molecules, continuing through the increasing complexity of the development, in neighboring clay niches, of “Metabolism First,” “RNA World,” and other necessary components of life, to the encapsulation by membranes of the components in the niches, to the interaction and fusion of these membrane-bound protocells, resulting finally in a living cell, capable of reproduction and evolution. Biotite (black mica) in micaceous clay is the proposed site for this origin of life. Mechanical energy of moving biotite sheets provides one endless source of energy. Potassium ions between biotite sheets would be the source of the high intracellular potassium ion concentrations in all living cells.
HYPOTHESIS | doi:10.20944/preprints202005.0507.v1
Subject: Keywords: neurodegeneration; protein misfolding; Western Pacific; Guam; montmorillonite; bentonite; clay; mineral; ALS; Parkinson’s disease
Online: 31 May 2020 (20:43:13 CEST)
Neurodegenerative diseases of protein misfolding affect humans and animals. In humans, these diseases include Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and Western Pacific amyotrophic lateral sclerosis and Parkinsonism-dementia complex (ALS/PDC). Mineral exposure may be important in the pathogenesis of protein misfolding cascades. The possible association of bentonite, montmorillonite, and mineral risk factors with Alzheimer’s disease, Parkinson’s disease, ALS, and Western Pacific ALS/PDC is analyzed and discussed.
ARTICLE | doi:10.20944/preprints201812.0107.v1
Subject: Chemistry, Physical Chemistry Keywords: clay; diazonium salt; ion imprinted polymers; radical photopolymerization; visible light; adsorption; copper ions
Online: 10 December 2018 (14:27:52 CET)
There is an urgent demand worldwide for the development of highly selective adsorbents and sensors of heavy metal ions and other organic pollutants. Within these environmental and public health frameworks, we are combining the salient features of clays and chelatant polymers to design selective metal ion adsorbents. Towards this end, the ion imprinting approach has been used to develop a novel nanohybrid material for the selective separation of Cu2+ ions in aqueous solution. The Cu2+-imprinted polymer/ montmorillonite nanocomposite (IIP/Mt) and non-imprinted polymer/montmorillonite nanocomposite (NIP/Mt) were prepared by radical photopolymerization process in the visible light. Ion imprinting was indeed important as the recognition of copper ions by IIP/Mt was significantly superior to that of NIP/Mt that is the nanocomposite synthesized in the same way but in the absence of Cu2+ ions. The adsorption process as batch study was investigated under the experimental condition affecting same parameters such as contact time, concentration of ions metals and pH. The adsorption capacity of Cu2+ ions is maximized at pH 5. Removal of Cu2+ ion achieved equilibrium within 15 minutes; the results obtained were found to be fitted by the pseudo-second order kinetics model. The equilibrium process was well described by the Langmuir isothermal model and the maximum adsorption capacity was found to be 23.6 mg/g.
ARTICLE | doi:10.20944/preprints201801.0132.v1
Subject: Engineering, Civil Engineering Keywords: clay ball; asphalt pavement; pattern and density; infrared image collection system; field core
Online: 16 January 2018 (05:00:02 CET)
Clay ball is a pavement surface defect which refers to a clump in which clay or dirt is mixed with hot asphalt mixture. Clay ball is typically caused by a combination of aggregate contamination of clay or soil, high aggregate moisture, and low production temperature at the asphalt plant. It usually appears a few weeks or months after paving under traffic load, after being liquefied and knocked from the pavement surface. Clay balls can be the source of potholing, raveling, and other issues such as moisture infiltration and reduced ride quality. This paper presents an investigation of the clay balls on US-31 one winter after construction in Hamilton County, Indiana. In order to understand the pavement condition, their severity was measured using both visual observation and infrared image collection system. In addition, a clay ball distribution pattern, its density, and cores condition were evaluated. A precipitation effect on clay ball formation was investigated for finding a cause of the clay balls. The investigation found that infrared image collection system was appropriate in detecting the clay balls. The clay balls were elliptic in shape with 1 inch to 4 inches in diameter, and the maximum clay ball depth is almost penetrating the entire surface course. It was also found that the asphalt paving on the raining days or right after raining could increase the potential of clay balls. Monitoring of aggregate moisture during construction on or after raining days should be able to reduce the risk of clay balls.
ARTICLE | doi:10.20944/preprints202201.0022.v1
Subject: Life Sciences, Biophysics Keywords: clay; mica; biotite; muscovite; origin of life; abiogenesis; mechanical energy; work; wet-dry cycles
Online: 4 January 2022 (20:36:31 CET)
Intracellular potassium concentrations, [K+], are high in all types of living cells, but the origins of this K+ are unknown. The simplest hypothesis is that life emerged in an environment that was high in K+. One such environment is the spaces between the sheets of the clay mineral, mica. The best mica for life’s origins is the black mica, biotite, because it has a high content of Mg++ and it has iron in various oxidation states. Life also has many of the characteristics of the environment between mica sheets, giving further support for the possibility that mica was the substrate on and within which life emerged.
ARTICLE | doi:10.20944/preprints201811.0261.v1
Subject: Engineering, Civil Engineering Keywords: expanded glass; expanded clay; lightweight aggregate concrete; microfiller; alkali-silica reaction; freeze-thaw resistance
Online: 12 November 2018 (04:37:43 CET)
This study is focused on the experimental investigation of compressive strength and durability properties of lightweight concrete mixtures with fine expanded glass and expanded clay aggregates using different microfillers. The paper proposes the relationships between the compressive strength and density of concrete mixtures with different proportions of lightweight aggregates mentioned above. The performed experimental studies have revealed the tendencies of possible usage of different amount of fine lightweight aggregates and their combinations in the production of concrete mixtures depending on the demands of practical application. Following the requirements for structural concrete subjected to environmental effects, durability properties (alkaline corrosion and freeze–thaw resistance) of the selected concrete mixtures with expanded glass aggregate were studied. The results of the experimental investigations have shown that durability of tested concrete specimens was sufficient. The study has concluded that the mixtures under consideration can be applied for the production of structural elements to which durability requirements are significant.
ARTICLE | doi:10.20944/preprints202108.0087.v6
Subject: Engineering, Mechanical Engineering Keywords: stone block; polygonal masonry; clay model; pantograph; translator; parallelogram mechanism; replica; chisel; hammer; megalith; Inca; Cusco; Ollantaytambo; Machu Picchu; Sacsayhuaman; Peru
Online: 16 May 2022 (12:15:55 CEST)
The article suggests methods that allow creating the most complicated type of polygonal masonry found in Peru. This masonry type consists of large stone blocks weighing from several hundred kilograms to several tons fitted close to each other almost without a gap between complicated curved surfaces over a large area. The work provides a description of techniques, which apparently were used by builders who arrived from Europe. The techniques under discussion are based on the use of a reduced clay model, 3D-pantograph, topography translator and replicas. The use of a reduced clay model and a pantograph provides not only the unique appearance and high quality of masonry with large blocks, but also allows to significantly increase the productivity of the builders. As machines coping-scaling three-dimensional objects are known since the beginning of the 18th century, the stone structures under consideration should be approximately dated by this time. The remaining simpler types of polygonal masonry with smaller stones or fitted surfaces are almost flat, or stones contact with each other by a small area, or there are significant gaps between stones, are quite consistent with the well-known methods of stone processing of those and earlier years, and, therefore, they do not require any additional explanations.
Subject: Life Sciences, Molecular Biology Keywords: origin of life; origins of life; mechanical energy; work; entropic forces; mica; biotite; Muscovite; wet/dry cycles; clay
Online: 29 April 2019 (07:51:38 CEST)
Forces and mechanical energy are prevalent in living cells. This may be because forces and mechanical energy preceded chemical energy at life’s origins. Mechanical energy is more readily available in non-living systems than the various other forms of energy used by living systems. Two possible prebiotic environments that might have provided mechanical energy are hot pools that experience wet/dry cycles and mica sheets as they move, open and shut, as heat pumps or in response to water movements.
ESSAY | doi:10.3390/sci2020019
Subject: Keywords: origin of life; origins of life; mechanical energy; mechanochemistry; work; entropic forces; mica; biotite; Muscovite; wet/dry cycles; clay
Online: 25 March 2020 (00:00:00 CET)
Mechanical forces and mechanical energy are prevalent in living cells. This may be because mechanical forces and mechanical energy preceded chemical energy at life’s origins. Mechanical energy is more readily available in non-living systems than the various forms of chemical energy used by living systems. Two possible prebiotic environments that might have provided mechanical energy are hot pools that experience wet/dry cycles and mica sheets as they move, open and shut, as heat pumps or in response to water movements.
ARTICLE | doi:10.20944/preprints201907.0175.v1
Subject: Engineering, Civil Engineering Keywords: masonry structures; shear walls; clay brick (CB); calcium-silicate (Ca-Si) masonry units; autoclaved aerated concrete masonry units (AAC); bed joints reinforcement; shear strength; strain angle; wall stiffness
Online: 15 July 2019 (05:37:44 CEST)
The area of Central and Eastern Europe, and thus Poland, is not exposed to effects of seismic actions. Any possible tremors can be caused by coal or copper mining. Wind, rheological effects, the impact of other objects or a non-uniform substrate are the predominant types of loading included in calculations for stiffening walls. The majority of buildings in Poland, as in most other European countries, are low, medium-high brick buildings. Some traditional materials, like solid brick (>10% of construction materials market) are still used. But autoclaved aerated concrete (AAC) and cement-sand calcium-silicate (Ca-Si) elements with thin joints are prevailing (>70% of the market) on the Polish market. Adding reinforcement only to bed joints in a wall is a satisfactory solution (in addition to confining) for seismic actions occurring in Poland that improves ULS and SLS. This paper presents results from our own tests on testing horizontal shear walls without reinforcement and with different types of reinforcement. This discussion includes 51 walls made of solid brick (CB) reinforced with steel bars and steel trusses, results from tests on 15 walls made of calcium-silicate (Ca-Si) and AAC masonry units reinforced with steel trusses and plastic meshes. Taking into account our own tests and those conducted by other authors, empirical relationships were determined on the basis of more than 90 walls. They are applicable to design and construction phase to determine the likely effect of reinforcement on cracking stress that damage shear deformation and wall stiffness.
HYPOTHESIS | doi:10.20944/preprints202007.0100.v2
Subject: Medicine & Pharmacology, Allergology Keywords: amyotrophic lateral sclerosis; ALS; glacial; lake; clay; mineral; United States; Canada; Finland; Vermont; New Hampshire; Maine; Ohio; Wisconsin; Indiana; Minnesota; North Dakota; Montana, Idaho; Washington; Oregon; Colorado; Iowa; Utah
Online: 15 December 2020 (10:21:51 CET)
Amyotrophic lateral sclerosis (ALS) disease clusters are found in several countries worldwide. In the United States, ALS clusters are found in many states, largely within the northern United States. The cause of the increased rates of ALS in these areas remains indefinite. It is reported here that many ALS clusters are associated with sites of current or prior glacial lakes, or regions containing an abundance of silts and clay minerals. The potential significance of these findings in ALS is discussed.