White Clay Research Articles

Brownish Green Fired Clay Tiles Produced by Valorizing Green Glass Cullet and Sediment Soil

This paper aims to valorize waste materials for producing eco-friendly fired clay tiles. Green glass cullet and the water supply process waste; sediment soil have been utilized. In addition, local white clay is used to mix with waste materials for promoting the plasticity and easily forming of specimens. The Triaxial diagram has been employed to construct the formulas. Mixture’s formulation of this experiment consists of 23 formulas. Test samples are fired at temperature 950 °C. Physical properties of fired specimens are carried out and compared with Thailand Industrial Standards. The results show that formula A6 can pass TIS. 2508-2555 wall tiles of medium water absorption series. However, A6 only utilize 10% of sediment soil. Therefore, increasing sintering temperature to 1,050 °C for utilizing higher content of sediment soil has been examined. Twelve formulas of group A and C are selected to be further investigated. Results show that formula A6 and C6 can achieve TIS. 2508-2555. Formula C6 utilizing 30% and 60% of sediment soil and green glass cullet obtain the highest strength and lowest water absorption. Analyzing microstructure of this formula by Scanning Electron Microscope has found glassy phases. Furthermore, Wollastonite 2M, Nepheline and Albite are identified by X-Ray Diffractometer. It can be summarized that sediment soil mixed up with green glass cullet and local white clay can develop brownish green color fired clay tiles which can be further applied to the production of local ceramic factory.

Effect of magnesia additive on the morphology and physico‐mechanical properties of kaolinitic clays ceramics

AbstractNigeria is rich in various minerals, including crude oil and solid minerals. However, despite this abundance, effectively utilizing these resources remains a challenge. Kaolin, also known as white China clay, is a crucial raw material used in industries such as ceramics, paper, paint, plastic, and welding electrodes. Despite its plentiful availability in Nigeria, kaolin has not been adequately exploited. Consequently, Nigeria spends approximately 14.35 million USD annually to import refined kaolin to meet local demand, due to the lack of capacity to process it to the required industrial standards. This study investigates the effect of magnesia (MgO) on the morphology and physico‐mechanical properties of kaolinitic clay ceramics using the slip‐casting method. Various analytical techniques were employed to examine the kaolin, including X‐ray fluorescence (XRF), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). Also, compressive and flexural tests were conducted. The XRF analysis revealed that all samples contained SiO2 (54.41%wt), Al2O3 (34.05%wt), and other trace elements. The main mineral phases identified were quartz, microcline, and orthoclase. Among the samples, 30–200 exhibited the highest compressive strength at 218 MPa, while the highest flexural rigidity was observed in sample 15–200. The results indicated that MgO significantly affected the properties of kaolin, as the control sample had a compressive strength of 59 MPa. The study also found that the quantities of additives should align with stoichiometric requirements. Results showed hypo‐stoichiometry in samples 30–600 and 15–400, and hyper‐stoichiometry in sample 60–200. XRF, XRD, and FTIR spectra confirmed the elemental and chemical compositions of the samples, while SEM analysis revealed the morphological structure. It was observed that increasing the magnesia content from 10% to 30% led to an increase in pore spaces within the samples. TGA analysis provided insights into the relationship between mass loss and temperature variation in the ceramic samples, While The DTG curves explain the endothermic phase changes over changes in temperature; at 50–150°C, loss of the water phase is complete, at 300–400°C burning of organic matter phase is achieved and at 500–700°C endothermic dihyroxylation phase begins forming armorphous meta‐kaolin.

Porewater microbiomes in buried wetland soils: Synergic effects of water chemistry and redox gradients associated with hydrological processes

Abstract Interstitial water or pore water occupies the space between soil particles and provides “hotspots” and “fluvial networks” for microbial activities in floodplain soil. However, to date, we know very little about the microorganisms living in pore water and how they respond to environmental changes. This study aimed to understand microbial distribution and assemblage in riparian pore waters, and how they respond to water chemistry and redox gradients associated with hydrological processes. We analysed the annual changes of porewater microbial communities from the east and west banks of the White Clay Creek, a site at the Christina River Basin – Critical Zone Observatory, Pennsylvania, USA. Microbial abundances were quantified by epifluorescence microscopy and detailed community structures were characterised by high‐throughput sequencing. Water chemistry and redox gradients were also monitored and recorded, and their interactions with porewater microbiomes were analysed using correlations and multivariate analyses. Abundance of microbial cells increased during summer and late autumn. Wetland porewater microbiomes mainly contained Acidobacteria, Bacteroidetes, Nitrospirae and Proteobacteria, and microbiome structures were easily distinguishable from those in the underlying hyporheic gravel layer. Seasonal dynamics of bacterial community structure in the east and west wetlands were distinct, responding to floodplain topography and associated hydrological/geochemical processes. Iron (Fe)‐cycling bacteria (mainly Gallionellaceae and Rhodoferax spp.) dominated the porewater microbiome, and their relative abundance was significantly higher in the east than the west wetland. Furthermore, Fe‐oxidising bacteria (Gallionellaceae) were negatively correlated with Fe‐reducing bacteria (Rhodoferax spp.) at the east wetland. Microbial abundances (cell density) in pore waters showed similar seasonal patterns across stream banks, but microbial community structure did not. Microbiome assembly in pore water is correlated with water chemistry and redox gradients primarily associated with local hydrological processes. As a consequence of their significance for carbon (C) mineralisation and Fe reduction at terrestrial–aquatic interfaces, microbiomes in riparian pore waters and associated microbial activity play an essential role in C and mineral dynamics. These findings will inform future studies of the response of freshwater ecosystems to hydrological dynamics influenced by global climate change.

Isolation and characterization of Chromobacterium violaceum and antibacterial activities of its metabolite violacein

Violacein is a naturally-occurring bacterial secondary metabolite which is known to demonstrate a wide range of biological properties including antibacterial, antifungal, antiviral as well as anticancer and antitumor activities. Bacteria belonging to the genus Chromobacterium are the most studied microorganisms for violacein production. In this study, indigenous violacein-producing Chromobacterium violaceum was isolated from water and sediment samples of Bijaypur white clay hill lake, Netrokona, Bangladesh, and identified by biochemical and molecular characterization. After confirming the presence of the vioB gene in a polymerase chain reaction, crude violacein was purified from C. violaceum CV1 by ethanol extraction followed by filtration through 0.22 µm syringe filters. The partially-purified pigment exhibited significant antibacterial activity against three Gram-positive pathogens; Staphylococcus aureus, Streptococcus sp, and Listeria monocytogenes, with the later demonstrating the highest sensitivity. The bactericidal activity was more pronounced when combined with an antibiotic, thereby producing a drug-metabolite synergistic antibacterial activity. Dhaka Univ. J. Biol. Sci. 33(1): 109-119, 2024 (January)

Use of Kaolin in the Pharmaceutical and Cosmetic Industries

Kaolin, a white clay mineral composed mainly of kaolinite with the chemical formula Al2O3.2SiO2.2H2O, has been a subject of interest since the days of medieval western literature. This interest increased especially after the advent of a more empirical approach to pharmacology, the establishment of pharmacopoeias, and developments in mineralogy, chemistry, as well as pharmaceutical technology. The use of kaolin in pharmaceutical (both topical and oral) and cosmetic applications has become important. Although it has long been recognized as a remedy in traditional medicine, the use of kaolin as an active ingredient for various diseases continues to be researched. Unfortunately, research focused on the use of kaolin in pharmaceuticals and cosmetics is still fairly limited. Therefore, this article aims to highlight the role and benefits of kaolin in both fields. Kaolin has been shown to have antibacterial, antiviral, and antidiarrheal properties when administered orally, as well as serve as a skin-protective agent when used topically. Aside from being an active ingredient, kaolin is also often used as an excipient in pharmaceutical formulations, acting as a filler, emulsifier, suspending agent, and crusher. In the cosmetic world, kaolin is often used as a sunscreen and to treat the skin. This article is organized based on a literature review of various articles and journals relevant to the topic discussed.

Comparative study for adsorptive removal of radioactive Cs+, Sr2+ and Co2+ ions from aqueous solution by acid-activated white clay

Comparative study for adsorptive removal of radioactive Cs+, Sr2+ and Co2+ ions from aqueous solution by acid-activated white clay

Physical, chemical and biological characteristics of clays from Durban (South Africa) for applications in cosmetics.

Clay soils are rock-decomposed materials comprised of both clay- and non-clay-like minerals. Clays' physiochemical and mineralogical composition determines their applicability use in cosmetics. Because of their high bioburden, they must be effectively characterized before being incorporated into cosmetics. The scope of the current study was to characterize two different samples of red and white clays for their physical, chemical and biological properties; mined from Durban, South Africa. Characterization was performed using techniques like X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, hydrogen potential, soil colour, oil absorption, swelling capacity, texture, bulk density, plastic and apparent viscosity, sun protection factor and microbiological analysis.

Ceramic Fine Wares of Natakamani and the Problem of Identifying the “Imperial Style” in the Material Culture of Meroe (Sudan)

The article analyzes ceramic fine wares of the ancient Meroitic Kingdom, made of white kaolinite clays (“eggshell wares”). This pottery appeared not earlier than the 1st century B.C. and gained popularity in the 1st–2nd centuries A.D., during the reign of king Natakamani and his successors. The kaolinite clays required professionalism and specific skills from ancient potters, as well as the availability of improved pottery wheels and kilns. Clay deposits were located near Meroe Royal City and in several other regions. The vessels were decorated with stamped or painted decoration in Egyptian or Hellenistic style and were distributed from Sennar and Abu Geili in the south to Karanog and Shablul in the north, being a clear marker of the Meroitic civilization. These complex wares could not be produced locally and became a marketable commodity. The morphological assortment of Meroitic fine wares is quite modest, while standardization of the shape and volume is noticeable, which may indicate centralized control over pottery workshops. The stylistic uniformity of the vessels suggests the existence of a special “Imperial” style of pottery in the time of Natakamani and his successors. At the same period plans of settlements, the architecture of palaces and temples, cult objects also demonstrated uniformity, which could be associated with state control of administrative centers and craft workshops. The decline of royal power in the 3rd – mid-4th centuries A.D. was synchronous with the degradation of Meroitic fine kaolin ceramics and its gradual replacement with wadi clays of grayish-beige colour and simplified decoration.

Определение зависимости кажущейся плотности керамических образцов от формовочной влажности глинистого сырья и давления прессования на основе регрессионных моделей

The paper proposes to use white clay with the highest apparent density to improve the production of wire-ceramic resistors. Preliminary studies of white clay have shown that it is more sensitive to drying than red clay. The intensity of moisture output from the center of the product to its surface during the manufacturing process and the drying characteristics of white clay give greater shrinkage and strength of dry samples. Linear and nonlinear multiple regression models with and without multicollinearity are considered to find the dependence of the apparent density of clay raw materials on humidity and pressing pressure. To clarify the model structures, a two-stage approach is used, which involves building a model for residuals. It is found that the combination of a multiple regression model taking into account multicollinearity with an AR model constructed for residues makes it possible to calculate the apparent density of clay raw materials with the smallest standard deviation from experimental data. The obtained model structures will be used to determine the optimal parameters of forming ceramic samples: the moisture content of clay raw materials and the compaction pressure, at which the greatest apparent density of samples is achieved. This will improve the production technology of wire-ceramic resistors. The use of wire-ceramic resistors based on white clay with the highest apparent density will speed up one of the stages of the technological process – drying and reduce their hygroscopicity. As a result of the use of wire-ceramic resistors with the highest apparent density, the mechanical strength of the products will increase, which will improve the operational characteristics and prolong the life of the products.

Effect of White Clay- and Oyster Shell Powder-Ground Layering on the Painting Layer Stability of Traditional Dan-Cheong

In the study, a deterioration test was conducted after making a test specimen by reenacting the “Ground layering” technique, one of the traditional Dan-Cheong techniques, with traditional materials such as White caly and oyster shell White. According to the results, the effect of Ground layering on the stability of Gachil layer and Painting layer of Dan-Cheong using traditional materials was analyzed. Surface state, color difference, and adhesion changes of the coating film before and after the deterioration test were quantified according to the evaluation criteria; by dividing the grades, the stability of Gachil layer and Painting layer was evaluated according to the application and Ground layering pigment to be based on apply Ground layering. As a result of the evaluation, fewer changes in surface state were observed in the specimen to which Ground layering was applied, oyster shell white Ground layering was more stable. In the Chromaticity change, there was less color difference change in the specimen to which Ground layering was applied, the oyster shell white was more stable. The change in adhesion was evaluated by dividing Powdery flaking and Plate flaking, and the specimen applied with Ground layering was more stable, and the oyster shell white was more stable. In conclusion, the Ground layering technique using traditional materials such as oyster shell white and white clay is believed to be helpful in improving the surface state, color difference, and adhesion of Gachil layer and Painting layer the in the traditional Dan-Cheong, and is more stable when applied using oyster shell white.

Application of laser heating to coat ceramic surfaces: An alternative for traditional Raku firing

This study presents a novel approach for coating ceramic surfaces with an organic material using laser heating. To achieve this, white clay ceramics were prepared and subjected to a 150W continuous wave fiber laser irradiation at 1090 nm for various durations. Following the laser treatment, a physical contact was established between an ostrich feather and the non-illuminated surface of the ceramic. As a result, the ostrich feathers underwent distinct stages of chemical changes known as pyrolysis, depending on the duration of laser illumination. Subsequently, the ceramics obtained were analyzed using SEM, EDX, XRD, and optical microscopy. Our experimental results indicate a specific temperature range between low temperatures (below 500 °C) where the pyrolyzed feathers do not adhere properly to the surface and higher temperatures (around and above 800 °C) where excessive pyrolysis occurs, resulting in an aesthetically pleasing pattern on the ceramic surface reminiscent of ostrich feather Raku. EDX and XRD analyses confirmed the penetration of feather residue into the structure of the non-illuminated surface, creating an artistic pattern, while the illuminated side displays a glazed and glassy like surface. Thus, these findings present a promising and innovative method that significantly reduces energy consumption and process time when compared to traditional Raku pottery approaches.

Study of the activation of Truc Thon ball clay by acids

Natural clay minerals have attracted attention for their availability and economical cost as adsorbents in the treatment of contaminants in aquatic environments. In this study, Truc Thon white ball clay from Hai Duong province, Vietnam was activated by different acids including H2SO4, HCl and H3PO4 at 110°C from 6 to 18 hours under refluxing conditions. The chemical composition and structure changes before and after the activation of the clay were characterized by X-ray fluorescence, X-Ray Diffraction and Fourier transform infrared spectroscopy. The raw clay is mainly composed of minerals containing alumina and silica while in activated clay, silica is dominant in amorphous phase. The specific area of clay particles was increased significantly after acid treatment from 10.55 m2.g-1 to 178.53 m2.g-1. Images from a scanning electron microscope also reveal more porous structure of activated clay. These behaviors make acid activated clay highly effective in various adsorption applications.

Mechanical properties of white clay used as wall painting substrate material: measurement of strength and modulus of elasticity of simulated substrate material of wall paintings Hiten at Kondo, the main hall at Horyu-ji Temple

Preserving cultural artifacts while minimizing the energy consumption and costs associated with environmental control is crucial. This often requires predicting artifacts degradation caused by temperature and humidity. Here, mechanical damage can be predicted by comparing stress and damage criteria. Although the constitutive coefficients and damage criteria of various materials have been extensively studied, the mechanical properties of white clay remain unknown. This material is a crucial component of various artifacts including some important cultural artifacts and national treasures of Japan. Thus, this study aims to identify the strength and elastic properties of simulated white clay mimicking the substrate of the wall paintings Hiten at Kondo, the main hall at Horyu-ji Temple. Following existing literature, we created the simulated white clay by combining clay, paper fiber, and rice glue. We fabricated 36 distinct specimen patterns by varying the equilibrium humidity and material mixing ratios. We measured the tensile strength using splitting tensile tests and, compressive strength, Young's modulus, and Poisson’s ratio using compressive tests. The tensile strength, compressive strength, Young’s modulus, and Poisson’s ratio ranged from 0.0785–1.17(MPa), 0.358–3.67(MPa), 0.0394–0.274 (GPa), and 0.10–0.44(-), respectively, with variations depending on the equilibrium humidity and ratio of material mixing. We also formulated the results as functions that depend on the equilibrium humidity and material mixing ratios. These findings can be used to predict stress and damage to targeted wall paintings and to inform the preservation and restoration of cultural artifacts containing white clay.Graphical

Fabrication and characterization of coated ceramic membranes from natural sources for water treatment applications

This study aimed to fabricate ceramic membranes for water treatment applications using natural and cost-effective materials. This is the first-time white clay, Arabic gum, and marble powder were used in ceramic membranes. Two ceramic membranes were fabricated using an extrusion process: substrate A and substrate B. The JMP software (Version 15) was used to obtain the optimal recipes for the two substrates, which were white clay (62.7 %), silica flour (32.3 %), and Arabic gum (5 %) for substrate A and white clay (63 %), silica flour (26.8 %), and marble powder (10.2 %) for substrate B. Additionally, the effect of waste glass in the coating layer on the separation rate was examined. The ceramic membranes were analysed using various techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), laser diffraction particle size analysis, thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM), and their chemical resistances were evaluated. The flux across the substrates was measured using a crossflow filtration system, and it was found that substrate B had a higher flux (116 L/m2h) than substrate A (77 L/m2h). This was probably due to its higher porosity (34 %) compared to substrate A (29 %). Substrate A, with a coating layer (CO-2), exhibited the highest removal efficiency of approximately 99.2 % for synthetic feed water composed of tap water and bentonite clay, with an average particle size of 1.1 μm and turbidity of 13 ± 0.2 NTU. The costs of ceramic membranes A and B were estimated to be approximately 51 and 47 USD/m2, respectively. Their cost-effectiveness results from the use of low-cost materials that do not require high sintering temperatures. This study demonstrates that these ceramic membranes are not only affordable but also possess desirable properties for water treatment applications.

Carbon-Based Solid Acid Catalyzed Esterification of Soybean Saponin-Acidified Oil with Methanol Vapor for Biodiesel Synthesis

In this study, carbon-based solid acids were used to catalyze the esterification of soybean saponin-acidified oil (SSAO) with methanol vapor for the synthesis of biodiesel. The esterification conversion under different conditions was determined, and the catalyst components were determined using acid-base titration, elemental analysis, and inductively coupled plasma spectroscopy. The results showed that the conversion of SSAO under the optimal esterification conditions (i.e., catalyst loading of 6 wt%, methanol/oil molar ratio of 50:1, reaction temperature of 76 °C, and reaction time of 4 h) was 98.9%. The conversion was still higher than 80% after the catalyst was reused for four batches. The methanol vapor esterification (MVE) effectively mitigated the leaching of sulfonic acid groups and the production of sulfonate esters, while the activated white clay adsorption can significantly reduce the metal ion content in SSAO, which weakens its ion exchange with sulfonic acid groups. MVE for biodiesel synthesis is less costly compared to liquid methanol esterification because of the high recovery of methanol and the improved catalyst stability. Therefore, the addition of methanol in the form of vapor in the carbon-based solid acid-catalyzed esterification system is an effective way to maintain the catalyst activity and reduce the production cost of biodiesel.

Isolation, Identification, and Application of Pigment-Producing Actinobacteria from Stingless Bee Hives for Handicraft Production

Actinobacteria are distributed in natural habitats and produce a vast variety of natural pigments that are different in colour shades and applied in textile industry and others. The extracted actinobacterial pigments are used as eco-friendly natural dyes and colour and non-toxic to living organisms and environments compared with chemical or synthetic colours. In order to produce actinobacterial pigments for handicraft making, eight strains of the pigmented producing actinobacteria were isolated from stingless bee (Tetragonilla collina Smith, 1857) hives. Based on deep colour shades presented, 4 actinobacterial strains were chosen to prepare various colour for handicrafts, including yellow, violet, green, and pink. To identify actinobacterial strains selected, phylogenetic identification was carried out. The phylogenetic results indicated that strain C2 phylogenetically shared the 16S rDNA sequence 99.6 % similarity with its closest species, namely Streptomyces cellulosae. Strain C4 had the phylogenetic relationship close to Streptomyces californicus (99.9% similarity of 16S rDNA). Strain E1 was a closest member belonged to Streptomyces chartreusis (99.9% 16S rDNA sequence similarity), and strain E2 was phylogenetically closely related to Streptomyces aureoversilis with 99.2% 16S rDNA sequence similarity. To produce the handicraft colour, we cultivated four actinobacterial strains on broken-milled rice, and actinobacterial pigments were extracted using ethyl acetate. The crude extracts obtained were mixed with white flower clay that was used for handicraft making, and the artificial clay flowers were made. This study is the first to report the use of natural colours obtained from pigment-producing actinobacteria in handicrafts in Thailand and other countries. Future research will explore the application of actinobacterial pigments in various fields, including fine arts, the ceramic industry, and others.

Search for Qualified Soil for the Production of Low-Energy Biobased Composite Materials

The development of earth-based bio-sourced materials requires a thorough analysis of the study soil. For the present study, we took five (05) soil samples from a tunnel-digged quarry in the layer between 0.5 m and 5 m : white clay (MSB-BL), red clay (MSB-RG), weak clay or sandy clay (MSB-FB), strong clay (MSB-FR) and mixture (MSB-ME). To verify the quality of these five (05) soils samples, their intrinsic properties were determined at the National Building and Public Works Laboratory (LNBTP). These included grain size, clay content, specific weight, loss on ignition and moisture content. These analyses revealed that MSG-RG and MSG-BL clays have fine fractions of 64.28% and 47.85% respectively; clay fractions of 27.51% and 20.61% respectively; and methylene blue values in the range (6;8). Their plasticity indices are in the range (20;40). These two (02) clays thus meet the requirements in terms of granularity, and their relatively high clay fraction will favor their adhesion with admixtures such as plant fibers. What's more, the particle size distribution of these clays is within the ideal CRAterre range for soils used in the manufacture of BTC or adobes, so they are all eligible.

Pre- and postsettlement depositional processes and environments of the 3rd- to 5th-order White Clay Creek watershed, Piedmont Province, Pennsylvania and Delaware, USA

We extend two hypotheses based on studies of 1st- to 3rd-order Piedmont watersheds of southeastern Pennsylvania, USA, by collecting data in a larger 3rd- to 5th-order watershed nearby. One hypothesis posits that presettlement river corridors were dominated by wetlands, and the other suggests that river valleys were filled by millpond sedimentation following European settlement. Both hypotheses support new river restoration practices, so their generality is important to assess. Ten lithofacies indicate depositional environments, while pedostratigraphic criteria and 14C dating define presettlement and postsettlement stratigraphic units. Basal gravels similar to modern stream bed sediments represent presettlement channels with active bedload transport. Wedge-shaped gravel deposits resembling modern bars further document presettlement bedload transport by channelized flows. Extensive presettlement and postsettlement units of massive, organic-poor, fine-grained sediment formed when overbank flows inundated floodplains. Peat deposits, exposed at a single site (but absent elsewhere), represent a presettlement wetland. Decimeter-thick, discontinuous, massive carbonaceous fine-grained sediments occasionally overlie basal gravels; these may represent localized wetlands adjacent to presettlement channels or hydraulic backwater environments. Laminated sand and mud accumulated behind one 3-m-high mill dam, but these millpond deposits are absent at other sites. Instead of being dominated by wetlands, presettlement river corridors are better described as a complex mosaic of riparian environments including older colluvial landforms, floodplains (some of which may have been seasonally inundated wetlands), primary (and possibly secondary) channels, and depending on geomorphic setting, either localized or valley-spanning wetlands. After European settlement, millponds were important locally, but their deposits represent a minor component of the stratigraphic record.

Novel formulations improve the environmental tolerance of entomopathogenic nematodes

Entomopathogenic nematodes (EPN) are susceptible to environmental factors such as ultraviolet (UV), for which formulations of EPN infective juveniles (IJs) were explored. In the screening test for Steinernema carpocapsae, liquid starch displayed the greatest UV protection, followed by white kaolin clay (WKC), watergel and Barricade. In concentration tests, after 20-min UV S. carpocapsae IJs mixed in WKC caused 100% mortality of Galleria mellonella larvae at ≥5% concentration and had lower IJ mortality than aqueous IJs at 0.5%-10% WKC. Liquid starch showed increased UV tolerance with concentrations up to 30% and 50% for IJ viability and virulence, respectively. The WKC, liquid starch, Barricade and watergel were further compared to water using S. carpocapsae and Heterorhabditis floridensis. H. floridensis was more susceptible to UV radiation than S. carpocapsae. Liquid starch provided the strongest protection of both EPNs in IJ viability and virulence, with more prominent effects for S. carpocapsae than H. floridensis. The WKC and Barricade improved the viability of both EPNs after UV treatment, but only WKC enhanced S. carpocapsae virulence. The number of invading S. carpocapsae decreased as UV exposure time increased for WKC and only decreased at 20-min UV for liquid starch. Very few H. floridensis invaded insects after UV exposure regardless of treatments. In outdoor soil tests, liquid starch and WKC protected S. carpocapsae but were inferior to Barricade and watergel, probably associated with anti-desiccation. Overall, liquid starch and WKC improved the UV tolerance of EPNs, although the effects were less pronounced in soil involving other factors.

Production of autoclaved lightweight concretes using pottery stone and bagasse ash

This study investigated the influence of pottery stone and bagasse ash on the mechanical features of autoclaved lightweight concrete. Pottery stone is a natural resource of igneous rock weathering commonly exists with white clay, feldspar and limestone. This raw material is mainly composed of quartz and mica that has been used for the production of ceramic products. Bagasse ash is a waste product of the sugar refining process that causes serious environmental pollution. Pottery stone and bagasse ash waste were physically characterized and partially substituted by the weight of cement in lightweight concrete with the addition of aluminium powder at a certain amount. The use of aluminium powder showed a positive effect on the porosity of lightweight bodies. Compressive strength, density and thermal conductivity were determined. Pottery stone can be used as a natural pozzolan for the production of lightweight concrete. Lightweight concrete manufactured with 17.5% pottery stone and 17.5% bagasse ash showed low density and good compressive strength. Autoclaved lightweight concrete is considered an economy in the consumption of pottery stone and bagasse ash waste as cement replacement, therefore enhancing the possibility of its reuse in a sustainable way.