Apparent Water Research Articles

Effective Stabilization of Cadmium and Copper in Iron-Rich Laterite-Based Geopolymers and Influence on Physical Properties.

This study aimed to investigate the efficiency of a geopolymer binder of the type of Na-poly(ferro-silico-aluminate) as a matrix for the stabilization of heavy metals along with their effect on the development of structural performances. The artificial contamination of soil with ions was carried out and used to prepare an alkali-activated iron-rich lateritic soil binder. Further, various microstructural analyses were carried out to explain the stabilization mechanism. The stabilization efficiency was assessed by leaching tests in de-ionized water and hydrochloric acid (0.1 M, HCl). Then, the physical properties were determined to evaluate the impact of heavy metals on the structural performance of the binder. Results demonstrated that the prepared geopolymer binder has the lowest stabilization capacity in an acidic medium (low pH) than in water with high pH. However, the stabilization of Cu ions was effective at 99%, while the Cd ion is barely retained in the matrix. Firstly, the mechanism consists of chemical bonds through ion exchange with sodium of the Na-poly(ferro-silico-aluminate) network. Secondly, through physical interaction with the pore network of the matrix, the heavy metals induced structural deterioration in the geopolymer matrix with a decrease in the compressive strength and bulk density and an increase of both apparent porosity and water absorption.

Mechanical properties of ignimbrites of Tenerife Island employed as building stone and their correlation with some physical properties

The aim of this research work was to determine and analyse the mechanical properties of a group of four varieties of ignimbrites, which are differentiated according to their colour: brown, violet, grey and green. These ignimbrites are mined in the southern part of Tenerife (Canary Islands) and are widely used as building stone. Mechanical characterisation was carried out by determining: ultrasound propagation velocity, uniaxial compressive strength, flexural strength under concentrated load, point load strength, Schmidt hammer rebound number and rupture energy. To evaluate the influence of the anisotropy planes and the degree of correlation between the different directions, all tests were done in more than one direction, except for the rupture energy. A simple regression analysis incorporating the physical properties available in the literature is included, with special emphasis on those with the highest correlation coefficient. Finally, a multiple regression analysis is performed to find the best fitting equations to predict the compressive strength. Of the four varieties studied, the green ignimbrite proved to be the one with the highest mechanical strength, with some properties three times higher than those obtained for the brown ignimbrite and almost twice as high as those obtained for the violet ignimbrite and the grey ignimbrite, the latter varieties having a similar behaviour to each other. In most cases, the behaviour of the ignimbrites studied is consistent with their lithology, but some properties of the green ignimbrite exceed the range reported in the literature, thus providing a new reference for this lithotype. Simple regression analysis revealed strong correlations between uniaxial compressive strength and water absorption (r = −0.89) and point load strength (r = 0.85). Flexural strength showed very strong correlation with ultrasonic velocity (r = 0.91) and point load strength (r = 0.95). Applying the multiple regression method, the best estimators of compressive strength found were a model with four independent variables; apparent density, open porosity, water absorption and Schmidt hammer rebound index (R2 = 0.91) and a model with five variables, adding point load resistance (R2 = 0.93).

Physical and Hydrodynamic Textural Parameters of Soils: The Case of the Rubber Plantations of the Centre National de Recherche Agronomique (CNRA) Anguédédou in South-Eastern Côte d'Ivoire

The rubber tree, a species of Amazonian forest tree, is cultivated for its latex, which is rich in natural rubber. Its cultivation is of economic, social, climatic and environmental importance. However, it is often accused of destroying the soil. To clear up this misunderstanding, a study was carried out to characterise the physical and hydrodynamic characteristics of soils under rubber in south-eastern Côte d'Ivoire. According to the biotope (rubber plantation, abandoned rubber plantations and forest) and the age of the rubber plantations, this study selected 12 plots. These included ten rubber plantations that were divided into four age categories: 1-5 years, 6-10 years, 11-20 years, and 21-40 years. Additionally, a secondary forest was also selected as a control, which was located in close proximity to these plantations. Furthermore, a rubber plantation that had been abandoned for more than eight years was also selected considered as a transition between the active plantations and the secondary forest. In these biotopes, soil samples were taken using an auger and sent to the laboratory to determine soil texture. Using the Yoro sand method and the single ring device, the apparent density, porosity and water infiltration rate of the soils were determined. The results show that the soil texture of the CNRA Anguédédou rubber plantations in southern Côte d'Ivoire is generally clayey. On the other hand, the texture of the soils of the youngest plantations (1 to 5 years old) is silty-clayey with more than 37% clay and a low water content. However, the soils of old rubber plantations with a clay texture have high water content. The soil compactness observed in young rubber plantations is corrected as the plantations age.

Effect of Salt Mist Ageing on the Physical and Mechanical Properties of Two Ignimbrites from the Canary Islands (Spain).

The aim of this research work is to study the effect of salt mist ageing on the physico-mechanical properties of two ignimbrites from the Canary Islands (Spain). Due to their insular nature and extensive coastlines, these regions are highly susceptible to atmospheric salt aerosols, which is a significant weathering agent for building materials. The ignimbrites analysed are marketed under the names "Azul Lomo Tomás de León" and "Marrón de Abades" and are widely used as building stones. Petrographic, mineralogical and chemical properties were obtained via polarisation microscopy, X-ray diffraction and X-ray fluorescence. The samples were subjected to 60 cycles of a salt mist environment, following relevant European standards. Scanning electron microscopy images of the specimens were analysed along with physical properties, including apparent density, open porosity, water absorption, colourimetry and ultrasound propagation velocity, initially and after every 20 cycles, allowing us to assess their evolution during the ageing test. Mechanical properties were evaluated using uniaxial compressive strength and flexural strength under concentrated load tests on two groups of specimens: one unaged and the other subjected to 60 ageing cycles. With the exception of apparent density, the other properties show a decrease between 5% and 30%. However, open porosity increases and is one of the properties most affected by the ageing test.

Ocean Color Image Sequences Reveal Diurnal Changes in Water Column Stability Driven by Air–Sea Interactions

The southward propagation of cold-air frontal boundaries into the Gulf of Mexico region initiates a cascade of coupled air–sea processes that manifests along the coastlines as an apparent brightness anomaly in the ocean color signals. Our hypothesis is that the color anomaly is largely due to the turbulent resuspension of sedimentary particles. Initially, there is significant wind-driven ocean turbulence as the frontal boundary passes, followed by the potential for sustained convective instability due to significant heat losses from the ocean surface. These cold front events occur during boreal autumn, winter, and into early spring, and the latter episodes occur in the context of the seasonally recurring thermal stratification of shelf waters. Here, we show that as stratification reasserts thermal stability in the waning days of a cold front episode, daily to hourly ocean color patterns are temporally coherent with the air–sea heat flux changes and the resulting impact on water column stability. Concomitant results from a nested, data-assimilative, and two-way coupled ocean-atmosphere numerical modeling system provides both corroboration and insight into how surface air–sea fluxes and in-water turbulent mixing manifest as hourly changes in apparent surface water turbidity due to the potential excitation and settling of reflective particles. A simple model of particle mixing and settling driven by the simulated turbulence mimics patterns seen in the satellite image sequences. This study offers a preview of potential application areas that may emerge following the launch of a dedicated ocean color geostationary sensor.

Performance of eco-friendly concrete made from recycled waste tire fine aggregate as a replacement for river sand

Tires are non-biodegradable and can last long, providing an environmental risk. This material could substitute natural aggregate in concrete, reducing aggregate consumption, promoting sustainable development, and protecting the environment. This study examines the mechanical strength, shrinkage, durability, and structural performance of concrete prepared with varied content of waste tire fine aggregate (WTFA) up to 75 % as a substitute for sand at two water-to-cement ratios of 0.30 and 0.55. Results indicate that slump, dry density, and mechanical strength all decrease as WTFA content increases. At both w/c ratios, the compressive and splitting tensile strength decreases by up to 71–77 % and 59–62 %, respectively, when the WTFA content is 75 %. Young's modulus dropped by about 71–77 % when the WTFA content was 75. In contrast, the flexural load-carrying capacity declined by about 63–69 % for the beam with 75 % WTFA. The 100-day shrinkage test reveals no apparent shrinkage up to 20 % WFTA. However, the control specimens show the lowest shrinkage. Further, increased WTFA content increased the apparent porosity, water absorption, and chloride ion penetration. Nevertheless, the statistical analysis (ANOVA) revealed no significant effects on mechanical and durability properties due to incorporating WTFA in concrete. The outcome demonstrates that 20 % WTFA can be used as a replacement for river sand in many structural concrete whose design strength is not significantly high (fcat28days ≈ 20 MPa).

Simple UV-Grafting of PolyAcrylic and PolyMethacrylic Acid on Silicone Breast Implant Surfaces: Chemical and Mechanical Characterizations

Poly(dimethyl siloxane) (PDMS) is one of the most widely used materials in the biomedical field. Despite its numerous advantages, its hydrophobic character promotes bacterial adhesion and biofilm formation. For breast implants, biocompatibility is challenged due to the biofilm formed around the implant that can degenerate to severe capsular contracture over time. Thus, the laboratory has set up strategies to prevent bacterial contamination by grafting covalently hydrophilic bioactive polymers on the surface of implants. In this study, poly(methacrylic acid) (PMAc) and poly(acrylic acid) (PAAc) were chosen as non-toxic and biocompatible bioactive polymers known for reducing bacteria adhesion. These polymers are also good candidates to lend reactivity on the surface for further functionalization. X-ray photoelectron Spectroscopy (XPS) and Fourier-Transform Infrared spectroscopy (FTIR) analysis have highlighted the covalent grafting of these polymers. Apparent water contact angle measurements have shown the change in hydrophilicity on the surface, and a colorimetric assay allowed us to assess the grafting rate of PMAc and PAAc. Tensile strength assays were performed to ensure that the functionalization process does not significantly alter the material’s mechanical properties. Analyses of the surface aspect and roughness by Scanning Electron Microscope (SEM) and optical profilometer allow us to formulate hypotheses to approach the understanding of the behavior of the polymer once grafted.

Trifolium repens L.-Like Periodic Micronano Structured Superhydrophobic Surface with Ultralow Ice Adhesion for Efficient Anti-Icing/Deicing.

Wind turbine blades are often covered with ice and snow, which inevitably reduces their power generation efficiency and lifetime. Recently, a superhydrophobic surface has attracted widespread attention due to its potential values in anti-icing/deicing. However, the superhydrophobic surface can easily transition from Cassie-Baxter to Wenzel at low temperature, limiting its wide applications. Herein, inspired by the excellent water resistance and cold tolerance of Trifolium repens L. endowed by its micronano structure and low surface energy, a fresh structure was prepared by combining femtosecond laser processing technology and a boiling water treatment method. The prepared icephobic surface aluminum alloy (ISAl) mainly consists of a periodic microcrater array, nonuniform microclusters, and irregular nanosheets. This three-scale structure greatly promotes the stability of the Cassie-Baxter state. The critical Laplace pressure of ISAl is up to 1437 Pa, and the apparent water contact angle (CA) is higher than 150° at 0 °C. Those two factors contribute to its excellent anti-icing and deicing performances. The results show that the static icing delay time reaches 2577 s, and the ice adhesion strength is only 1.60 kPa. Furthermore, the anti-icing and deicing abilities of the proposed ISAl were examined under the environment of low temperature and high relative humidity to demonstrate its effectiveness. The dynamic anti-icing time of ISAl in extreme environments is up to 5 h, and ice can quickly fall with a speed of 34 r/min when it is in a horizontal rotational motion. Finally, ISAl has excellent reusability and mechanical durability, with the ice adhesion strength still being less than 6 kPa and the CA greater than 150° after 15 cycles of icing-deicing tests. The proposed structure would offer a promising strategy for the efficient anti-icing and deicing of wind turbine blades.

Production potential of pulse-and oilseed-based climate-resilient alternative cropping systems for diversification of rice (Oryza sativa)–wheat (Triticum aestivum) in North-western Indo-Gangetic Plains

A field experiment was conducted during 2016–17, 2017–18 and 2018–19 at the Punjab Agrcultural University, Ludhiana, India, to evaluate the economic feasibility of pulse-and oilseed-based new alternative cropping systems in comparison to rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system. Among the 10 cropping systems evaluated in a randomized block design on a loamy sand soil, the highest rice-equivalent yield (23.2 t/ha) was obtained in groundnut (Arachis hypogaea L.)–garden peas (Pisum sativum L.)–sunflower (Helianthus annuus L.) with highest sustainable- yield index (0.81), followed by groundnut –garden peas– spring maize (Zea mays L.) (22.5 t/ha) as significantly better than rest of the cropping systems. In comparison to conventional rice–wheat system, higher net returns as well as relative economic efficiency were recorded in 4 cropping systems, viz. groundnut–garden peas–sunflower, groundnut–garden peas–spring maize, rice–wheat–summer mungbean [Vigna radiata (L.) R. Wilczek] and mungbean–toria [Brassica rapa subsp. dichotoma (Roxb.) Hanelt]–sunflower. Maximum apparent water productivity was observed in pigeonpea [Cajanus cajan (L.) Millsp.]–chickpea (Cicer arietinum L.)– summer mungbean, whereas the maximum nutrient-use productivity was observed in groundnut–garden peas– sunflower, followed by pigeonpea–chickpea–summer mungbean and the least values were recorded in rice–wheat system. Thus, resource-conserving biointensive cropping systems, viz. groundnut–garden peas–sunflower, groundnut–garden peas–spring maize, rice–wheat–summer mungbean and mungbean–toria–sunflower can be adopted for higher productivity, profitability and sustainability.

Canopy Structure, Light Intensity, Temperature and Photosynthetic Performance of Winter Wheat under Different Irrigation Conditions.

A high-quality canopy architecture is central to obtaining high crop yields. A field experiment was carried out at the Wuqiao Experimental Station from 2015 to 2019 under four irrigation schemes (W0, no irrigation after sowing; W1, 75 mm irrigation at jointing stage; W2, 75 mm irrigation at jointing and anthesis stages, respectively; W3, 75 mm irrigation at tillering, jointing and anthesis stages, respectively) to investigate the canopy structure, canopy apparent photosynthesis (CAP), canopy temperature (CT), yield and water use efficiency (WUE). The results showed that increasing irrigation times improved the leaf area index (LAI), non-leaf area index (NLAI) and light interception (LI) of the spike and total canopy but decreased the canopy temperature (CT) after anthesis. The CAP in the W3 treatment was consistently lower than that in the W1 treatment, suggesting lower effective utilization of light energy under the W3 treatment. Increasing irrigation times improved wheat yield, but the W2 treatment had no significant difference in yield compared to the W3 treatment. In addition, the W1 and W2 treatments had higher WUEs. The CT, organ temperature and LI were closely positively associated with each other, but they were all strongly negatively related to the yield. Overall, the W2 treatment was the best irrigation scheme for constructing a reasonable canopy architecture for winter wheat, obtaining more efficient water use and yield in the North China Plain (NCP). CT and organ temperature can be used as proxy parameters to estimate the canopy structure.

Multi-performance experimental assessment of autogenous and crystalline admixture-stimulated self-healing in UHPFRCCs: Validation and reliability analysis through an inter-laboratory study

The huge benefits brought by the use of Ultra High-Performance Fibre-Reinforced Cementitious Composites (UHPFRCCs) include their high “intrinsic” durability, which is guaranteed by (1) the compact microstructure and (2) the positive interaction between stable multiple-cracking response and autogenous self-healing capability. Hence, self-healing capability must be properly characterized addressing different performances, thus providing all the tools for completely exploiting such large potential. Within this context, the need is clear for a well-established protocol for self-healing characterization. To this end, in the framework of the Cost Action CA15202 SARCOS, six Round Robin Tests involving 30 partners all around Europe were launched addressing different materials, spanning from ordinary concrete to UHPFRCC, and employing different self-healing technologies. In this paper, the tailored experimental methodology is presented and discussed for the specific case of autogenous and crystalline-admixture stimulated healing of UHPFRCC, starting from the comparison of the results from seven different laboratories. The methodology is based on chloride penetration and water permeability tests in cracked disks together with flexural tests on small beams. The latter ones are specifically aimed at assessing the flexural performance recovery of UHPFRCCs, which stands as their signature design “parameter” according to the most recent internationally recognized design approaches. This multi-fold test approach allows to address both inherent durability properties, such as through-crack chloride penetration and apparent water permeability, and more structural/mechanical aspects, such as flexural strength and stiffness.

Quantitative myelin water imaging using short TR adiabatic inversion recovery prepared echo-planar imaging (STAIR-EPI) sequence.

Numerous techniques for myelin water imaging (MWI) have been devised to specifically assess alterations in myelin. The biomarker employed to measure changes in myelin content is known as the myelin water fraction (MWF). The short TR adiabatic inversion recovery (STAIR) sequence has recently been identified as a highly effective method for calculating MWF. The purpose of this study is to develop a new clinical transitional myelin water imaging (MWI) technique that combines STAIR preparation and echo-planar imaging (EPI) (STAIR-EPI) sequence for data acquisition. Myelin water (MW) in the brain has shorter T1 and T2 relaxation times than intracellular and extracellular water. In the proposed STAIR-EPI sequence, a short TR (e.g., ≤300 ms) together with an optimized inversion time enable robust long T1 water suppression with a wide range of T1 values [i.e., (600, 2,000) ms]. The EPI allows fast data acquisition of the remaining MW signals. Seven healthy volunteers and seven patients with multiple sclerosis (MS) were recruited and scanned in this study. The apparent myelin water fraction (aMWF), defined as the signal ratio of MW to total water, was measured in the lesions and normal-appearing white matter (NAWM) in MS patients and compared with those measured in the normal white matter (NWM) in healthy volunteers. As seen in the STAIR-EPI images acquired from MS patients, the MS lesions show lower signal intensities than NAWM do. The aMWF measurements for both MS lesions (3.6 ± 1.3%) and NAWM (8.6 ± 1.2%) in MS patients are significantly lower than NWM (10 ± 1.3%) in healthy volunteers (P < 0.001). The proposed STAIR-EPI technique, which can be implemented in MRI scanners from all vendors, is able to detect myelin loss in both MS lesions and NAWM in MS patients.

Study on Matrix Damage and Control Methods of Fracturing Fluid on Tight Sandstone Gas Reservoirs.

Hydraulic fracturing is a highly effective method for stimulating the development of gas reservoirs. However, the process of pumping fracturing fluid (FF) into the reservoir unavoidably causes damage to the surrounding matrix, leading to a decrease in the overall stimulation effect. To assess the extent of matrix permeability damage caused by the intrusion of FF, as well as its impact on the pore throat structure, and to propose appropriate measures to control this damage, we conducted a series of experimental studies on tight gas reservoirs. These studies included mercury intrusion, core flow, nitrogen adsorption, linear expansion, and contact angle measurements. The findings revealed that the damage inflicted on matrix permeability by FF was significantly greater than that caused by its gel-breaking counterpart. Surprisingly, the damage rate of the rejecting fluid to the matrix was found to be comparable to that of its gel-breaking counterpart. The fractal dimension (D2) was observed to have a strong correlation with surface area, pore volume, and mean pore size, making it an effective means of characterizing pore structure characteristics. After the rock samples were displaced by the formation water, the D2 value decreased, leading to a decrease in the complexity of the pore throat structure and an increase in matrix permeability. Conversely, the displacement of the FF increased the D2 value, indicating a gradual complication of the pore throat structure and a more uneven distribution of pore sizes. The inclusion of polyamide in antiexpansion FF, as well as its gel-breaking counterpart, proved to be effective in inhibiting the hydration and expansion of clay minerals, thereby reducing water-sensitive damage. Additionally, the use of surfactants with low surface tension enhanced the flowback rate of FF by increasing the contact angle and reducing the work of adhesion. This, in turn, helped to decrease the apparent water film thickness and expand gas flow channels, ultimately improving gas permeability.

Recycling of dolomite powder in clay bricks: Effects on characteristics and gas release

This paper evaluates the influence of dolomite industrial waste (dolomite powder (DP) on the properties, structure and durability of clay bricks. Four clay samples fired at 900 °C and 1000 °C containing 0 wt%, 10 wt%, 20 wt% and 30 wt% DP were prepared and investigated to measure their properties (shrinkage, bulk density, water absorption, thermal conductivity, apparent porosity, compressive strength), structure and durability (compressive strength after freeze thaw). The results showed a decrease in bulk density, compressive strength and an increase in apparent porosity and water absorption of the clay bricks produced by mixing 70–90 wt% clay and 10–30 wt% DP compared to the control bricks. Also, a significant improvement in the thermal conductivity of clay bricks produced by 70 wt% clay and 30 wt% DP (0.407–0.420 W/(m⋅K) compared to the control clay bricks (0.839–0.845 W/(m⋅K). As clay mixtures contain DP (chemical composition: CaO-49.68%, Loi-42.80%), CO2 emissions during the firing process are increased (decarbonation reactions). However, the thermal conductivity of the fired clay bricks is significantly reduced (to 50%). These results showed the potential of DP for the manufacturing of clay masonry units.

Sulfate resistance and degradation mechanism of basalt fiber modified graphite tailings cement-based materials

This paper delves into the modification mechanism and deterioration mechanism of basalt fiber (BF) on the sulfate resistance of graphite tailings (GT) cement-based materials. Initially, the comprehensive properties of basalt fiber modified graphite tailings cement mortar (BFM-GTCM) under different sulfate cycles, such as apparent morphology, water absorption and mechanical characteristics were investigated. Subsequently, the relationship between the evolution of microstructure, interface stability, pore structure, chemical composition and functional groups of BFM-GTCM and its resistance to sulfate erosion under different cycles was revealed by various microscopic characterization and analysis methods (SEM/XRD/MIP/FTIR/DSI). Simultaneously, a corrosion coefficient-pore structure relationship model was also put forth based on multivariate regression theory, and the mechanism enhancing BFM-GTCM resistance to sulfate attack was investigated. The results demonstrated that a suitable blend of BF and GT can prevent sulfate ion penetration, significantly slow down the generation of corrosion products (AFt and gypsum) in cement mortar during sulfate attack, postpone the occurrence of new cracks and the growth of existing ones, improve pore structure, and significantly lessen the degree of durability degradation of BF-GTCM. Among them, 0.3% BF addition and 20% GT replacement was the ideal ratio.

Effects of initial damage on self-healing of fly ash-based engineered geopolymer composites (FA-EGC)

The effect of initial damage levels on self-healing properties and the mechanism of fly ash-based engineered geopolymer composites (FA-EGC) was investigated. FA-EGC paste with an ultimate tensile strain exceeding 5.4% was prepared using fly ash, composite alkali activator, and PVA fibers. The FA-EGC specimens were pre-damaged by 1.5%, 2.0%, and 2.5% tensile strains, then self-healed for 7, 14, and 28 days. The self-healing properties of FA-EGC were studied by uniaxial tension, apparent crack characteristic, water absorption, and ultrasonic pulse velocity methods. The self-healing products were characterized by XRD, FTIR, BET, and SEM-EDS. The model of the relationship between initial damage levels and initial internal crack characteristics was built. The results showed that FA-EGC had significant multiple cracking characteristics, strain-hardening behavior, and ultra-high tensile ductility after 28 days of self-healing. After self-healing, the ultimate tensile strength of pre-damage FA-EGC recovered to 97.86% compared with the control specimen, and the ultimate tensile strain recovered to 94.50%. Moreover, the strain of ultra-high tensile ductility FA-EGC was up to 5%. Self-healing products were mainly amorphous aluminosilicate and calcium carbonate phases. The self-healing rate was determined by initial internal crack width according to the model, and FA-EGC had an initial damage threshold (about 2.0% tensile strain) with the lowest mean crack width and the highest self-healing rate.

Effect of molding pressure and firing temperature on the properties of ceramics from natural zeolite

In recent years, there has been growing interest in eco-friendly and sustainable construction materials that reduce environmental impact while maintaining high-performance standards. The brick industry, in particular, is under pressure to develop solutions that incorporate waste and natural-based materials, reducing reliance on traditional energy-intensive manufacturing processes. In response, this study explores the fabrication of ceramic bricks using naturally occurring zeolite, which is widely available and offers promising properties for use in construction. The ceramic matrix is made with natural zeolite and water, pressed at three different pressures, and fired at three different temperatures. The study investigates the impact of varying molding pressures and firing temperatures on the microstructural and mechanical properties of ceramic bricks made with natural zeolite. XRF and XRD techniques were used to analyze the raw material's chemical composition, and TGA tests were conducted to evaluate the bricks' chemical stability. The study finds that the compressive strength of zeolite bricks molded at 15 MPa pressure and fired at 900 ℃ increased from 7.1 MPa to 51.2 MPa when fired at 1100 ℃. Increasing the molding pressure led to a higher compressive strength of the specimens, but the effect was minimal compared to the influence of firing temperature on the compressive strength. The apparent porosity and water absorption of the bricks decreased with increasing molding pressure and firing temperature. Further, clinoptilolite, a zeolite phase, decomposes during firing and transforms into silica polymorphs, feldspathic phases, and glassy phases. As the molding pressure increased, the irregular-shaped pores in the brick specimens decreased. Moreover, the density of the bricks increased with the firing temperature due to sintering between particles in the microstructure. By investigating the impact of molding pressure and firing temperature on the microstructural and mechanical properties of these eco-friendly bricks, this study offers insight into a potential solution for sustainable construction practices. By investigating the impact of pressing pressure and firing temperature on the microstructural and mechanical properties of these eco-friendly bricks, this study demonstrated that optimizing firing temperature and pressing pressure can significantly improve the physical and mechanical properties of zeolite bricks, including bulk density, compressive strength, water absorption, and porosity, while also reducing the environmental impact of the production process. Thus, this study offers insight into a potential solution for sustainable construction practices.

Evaluation of the contents of ornamentals stones wastes and vegetable polyurethane resin in the production of engineered stones

The production of ornamental stones in Brazil has been increasing over the years. As a consequence, waste generation also increases. The objective of the present work was to evaluate the influence of different contents of ornamental stone wastes and vegetable polyurethane resin in the production of eco-efficient engineered stones. Initially, the characterization of the waste was carried out through the technique of X-ray fluorescence and X-ray powder diffraction. Subsequently, the engineered stone slabs were produced through the vacuum vibration and compression method, using quartzite waste as natural aggregate and vegetable polyurethane resin in the contents of 6, 8, 10, 12, and 14 wt%. The slabs were submitted to water absorption, porosity, density, mechanical resistance, scanning electron microscopy (SEM), and petrography tests. The results indicated that increasing the resin content decreased the apparent density, water absorption, and porosity of the engineered stones. The engineered stones produced with 10 wt% resin showed the best results, with greater flexural strength and acceptable density, water absorption, and porosity indices. Resin contents below 10% resulted in porous slabs, while contents above 10 wt%, the slabs showed elastic behavior and the presence of fractures and bubbles. Therefore, the use of these wastes for the manufacture of eco-efficient materials can contribute to the circular economy and can help to solve one of the biggest problems of the ornamental stone sector, and consequently, to reduce the negative environmental impact, can add value to the waste and contribute to sustainable development.

Novel Meta-iodobenzylguanidine and Etoposide Complex: Physicochemical Characterization and Mathematical Modeling of Anticancer Activity.

It is hypothesized that meta-iodobenzylguanidine (MIBG) complexation with etoposide (VP-16) will improve drug solubility and specificity towards BE(2)C neuroblastoma (NB) cells, 90% of which are known to be MIBG avid. After MIBG and VP-16 interaction, the dry complex was analyzed for crystalline structure, surface morphology, solubility, and size distribution by X-ray powder diffraction (P-XRD), scanning electron microscopy (SEM), infrared (FTIR) and UV spectroscopy, and dynamic light scattering. After exposure to the complex, the cell viability and decay rates were assessed by the MTS assay and estimated using exponential decay models (EDM). Multi-factorial ANOVA and an independent t-test were used to assess for cell viability and solubility data, respectively. The resulting (1: 3 w/w) VP-16: MIBG complex had a mean diameter and zeta potential of 458.5nm and 0.951mV, respectively. It dramatically increased the drug apparent water solubility (~ 12-folds). This was ascribed to the formation of a VP-16/MIBG nanocrystalline state mainly governed by cation-π interactions, evidenced by FTIR, SEM, and P-XRD data following the complexation. The EDM relating percent cell viability to drug concentration yielded an excellent fit (r2 > 0.95) and enabled to estimate the IC50 values of both native drug and its complex: 6.2μM and 5.23μM, respectively (indicating a conservation of drug anticancer activity). The statistical results were consistent with those of the exponential decay models, indicating that MIBG does not inhibit the anticancer activity of VP-16. This study indicates that the VP-16/MIBG complexation improves VP-16 solubility without antagonizing its anticancer activity. Moreover, the efficiency of the EDM for drug IC50 estimation provides alternative mathematical method for such in vitro cytotoxicity studies.

Reduced tillage and subsurface fertigation improve productivity and economic benefits in the cotton-wheat cropping system

Soil compaction under repetitive tillage and surface flood method of irrigation (SFMI) are significant hurdles for sustaining crop production in India, necessitating the adoption of efficient soil and water management strategies. Hence, a 3-year field study was conducted at two diverse agro-climatic locations (Abohar and Faridkot) to investigate the impact of subsurface drip (SUSD) fertigation on crop and water productivity of cotton-wheat cropping system (CWCS), over traditional practice (TP) (conventional tillage with SFMI and manual application of nutrients). The experiment was conducted in a factorial randomized complete block design with three levels of subsurface drip irrigation (SUSDI) [100, 80, and 60% of crop evapotranspiration (ETc)] and two fertigation levels [75% recommended dose of nutrients (RDN) and 100% RDN], where TP and surface drip (SD) fertigation at 80% ETc coupled with 100% RDN (Control 2), served as two control treatments. Cotton was raised through reduced tillage, while zero till drill was used for sowing wheat. The results revealed that, barring SUSDI at 60% ETc, both crops exhibited improved yield under all drip combinations of reduced or zero tillage over TP. Better mass and higher length of cotton roots in drip fertigation were evident due to improved steady-state infiltration rates (SSIR) and reduced bulk density (BD) under conservation tillage. When 100% RDN was applied, the 100% and 80% ETc SUSDI resulted in 26.7% and 24.7% higher seed cotton yield (SCY) than TP. Similarly, wheat yield with 100% RDN was improved by 10.5% and 14.4% under SUSDI of 80% and 100% ETc, respectively, over the TP. The results indicated that SUSD can be clubbed with reduced tillage for better soil health, improved crop yield, and higher apparent water productivity. The improved benefit to cost (B:C) owing to enhanced monetary returns over TP also substantiated that reduced tillage with SUSD is a viable and remunerative practice for CWCS. The study elucidated that reduced tillage exercised a beneficial effect on physical soil properties by lowering BD and improving SSIR. At the same time, SUSD could save huge amounts of irrigation water besides enhanced input use efficiency leading to higher crop productivity.