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Lignocellulose comprises a significant portion of municipal solid waste (MSW) - 40-70% in developed countries, including paper, wood, and yard waste. Cellulose and hemicellulose are often shielded by lignin, posing a barrier to waste decomposition and landfill gas generation. Unfortunately, lignin is resistant to microbial degradation under low-oxygen conditions that normally occur in MSW landfills. The bacterium strain TAV5, microaerophilic and member of phylum Verrucomicrobia, isolated from the hindgut of the Reticulitermes flavipes termite, the most widely distributed subterranean termite in North America. Its genome contains genes associated with methylotrophic competency which code for enzymes that structurally modify lignin. The overall goal of this research was to use TAV5 to modify lignin and boost methane production from MSW. Batch-scale reactors (125 mL) were filled with paper, yard, or wood waste, and four ratios of mixed of waste. Reactors were seeded with different ratios of TAV5 to anaerobic digester (AD) microorganisms (representing landfill anaerobic microorganisms). Based on batch tests, optimal ratios of TAV5 to AD microorganisms were used to seed wastes (mixed, yard, and wood) in 6-gallon reactors. Addition of TAV5 increased methane production from mixed waste, yard waste, and wood, by 49%, 34%, and 297%, respectively. TAV5 decreased acid soluble lignin by 7-39%, depending on waste type. TAV5 grown under aerobic conditions and room temperature (not requiring a heated anaerobic chamber) was found to remain viable and increase methane production under low-level oxygen conditions (1-2%). This finding will potentially lessen costs for growing large volumes of it for seeding landfills.

CuO nanoparticles (NPs) stand out due to their inherent antibacterial activity, cost-effectiveness, and tunable bandgap, rendering them promising for medical, disinfection, environmental, and industrial applications. Our study aimed to synthesize CuO NPs using fish scale (FS) waste and assess the impact of calcination temperature (100 °C, 300 °C, 500 °C, and 700 °C) on their structural and antibacterial properties. XRD analysis confirmed the formation of monoclinic structured CuO, corroborated by XPS analysis indicating a Cu2+ oxidation state. Crystallographic parameters such as lattice dimensions, the volume of the unit cell, the density of the unit cell, micro-strain, and dislocation density for all four CuO NP samples were calculated using established equations. The crystallite size was estimated by employing the Scherrer equation, linear straight-line method (LSLM), Williamson–Hall (W–H) method, Halder–Wagner (H–W) method, Monshi–Scherrer (M–S) method, and size–strain plot (SSP) method. Based on the highest value of the coefficient of determination (R2), the appropriateness of the measurement techniques was determined, and the crystallite sizes were found to be 10 nm, 11 nm, 24 nm, and 35 nm, respectively. The particle size was estimated based on the FESEM and TEM images, both of which showed an increase in size with calcination temperature. FTIR detected the presence of amide bands, which originated from the FS, and the EDX analysis provided qualitative and quantitative elemental measurements. The antibacterial activity was investigated against two Gram-negative (E. coli and S. typhi) and two Gram-positive (B. megaterium and S. aureus) bacterial strains. Increasing the calcination temperature resulted in increased particle size, which led to reduced antibacterial activity. [ABSTRACT FROM AUTHOR]

There are millions of older buildings in the colder climate regions of the world where envelope upgrades are needed to improve the indoor quality of buildings, reduce energy costs, and lower greenhouse gas (GHG) emissions. This study assessed the global warming potential (GWP) with and without accounting for CO2 uptake in trees (biogenic carbon) for 20- and 100-year timespans of an exterior insulation panel. The panels consisted of six different materials with three-ply cross-laminated timber (CLT) as its main component. The net GWP100-Uptake impact when explicitly accounting for biogenic CO2 uptake over a 100-year time period was 7.2 kgCO2-eq/m2 which was 92.7% lower than if it was not included (GWP100-Fossil of 98.7 kgCO2-eq/m2). Using a 20-year GWP increased the impact of the GWP fossil by 21.7% and the CO2 uptake scenario by 298%. The major contributor was the energy used for manufacturing panel's materials (53%), with embodied carbon in bio-products primarily responsible for offsetting emissions. The findings will be helpful for policymakers in setting net-zero carbon emission goals for embodied and operational impacts of building materials. [ABSTRACT FROM AUTHOR]

Wound healing requires a substantial amount of moisture for faster recovery. Completely hydrophobic or hydrophilic biomaterials are not suitable to be applied for cell growth in wounded areas. The study aimed to prepare a nanofibrous scaffold from the blend of a solution of hydrophobic PLA and a solution of hydrophilic gelatine. The stability of the blend was achieved using a surfactant and an electrospun nanofibrous scaffold was made out of the solution. The optimum composition of gelatine and PLA to make a scaffold of uniform fibre diameter was achieved with the help of conductivity, viscosity and FESEM analysis. The optimum scaffold was characterised by TGA, DSC and XRD analysis. The water contact angle of the optimum sample was observed at 27°. The blended scaffold was found non-toxic to cells and showed a 30% faster healing of wounds in the rat model test compared to the healing rate of the PLA scaffold or the gelatine scaffold alone. The histological assay also supported the blend scaffold as an encouraging material for tissue regeneration. [ABSTRACT FROM AUTHOR]

Moisture and suction variation beneath pavement contribute significantly to the volumetric deformation of expansive subgrade in response to climatic loading. In order to quantify the damage due to climatic loading, estimation of moisture, and suction variation in pavement subgrade is of paramount importance. The objective of the current study is to investigate the moisture and suction variation in response to precipitation events with the aid of numerical modeling in the unsaturated pavement subgrade. In unsaturated soils where the voids are filled with both water and air, the SWCC describes the volume of the voids that remain filled with water as the soil drains pore water. The SWCC has been identified as the vital soil information required to analyze seepage, stability, and volume change problems involved in unsaturated soils. However, the selection of unsaturated flow parameters is typically laboratory-based which represents specific conditions rather than a dynamic scenario of the field. In this study, an attempt was undertaken to conduct numerical modeling using field generated unsaturated flow parameters along with five other predictive models. Results indicated the distinct variation of moisture and suction distribution in subgrade from the same rainfall event while using laboratory versus field generated SWCC unsaturated flow parameters. In addition, predicted model yielded output was also varying with the field generated parameters’ output. Instead of using laboratory-generated static parameters, it was found that field generated dynamic unsaturated flow parameters were able to capture better suction variation at the pavement subgrade.

Water balance covers for landfill closure are used as a barrier which act with the natural processes to reduce percolation. The ideal performance of water balance cover is characterized by the minimal quantity of percolation. The rate of percolation of water balance cover largely depends on unsaturated soil behavior. In this study, percolation was evaluated through unsaturated soil parameters of six instrumented lysimeters. The field instrumentation included moisture sensors, tensiometers, rain gauge, dosing siphon, and pressure transducer. Soil water storage (SWS) capacity (SA) was quantified from the soil water characteristic curves (SWCC) which were developed based on laboratory experiments and field instrumentation data. Required SWS (SR) was also measured from the field monitoring results. Based on analysis, the relative storage ratio (SR/SA) was observed to be greater than unity (1) in most of the cases, indicating potential percolation. The SR/SA was also found competent to identify the lysimeter with higher quantity of percolations. The estimated percolation from the laboratory experimented and field generated SWCCs fairly resembled with the actual field measured percolation. The analyzed results also developed a framework to estimate the thickness of the cover storage layer required to manage percolation for the specific region of the study area.

Abstract: The negative pore water pressure or soil suction has significant effect on the performance of geotechnical infrastructures (e.g., slope, pavement, embankment etc.). The unsaturated behavior of soil is not static, rather offers variation in response to climatic loading. The objective of the study was to evaluate field-based techniques of SWCC construction in terms of capturing these variation as compared to laboratory methods and predictive models. The field assessment could allow the quantification of hysteresis effect on the SWCC. Instrumentation data from one Texas, USA highway was used in this study. Soil Water Characteristic Curves (SWCCs) were regenerated utilizing co-located moisture and suction data from the field. Laboratory and field measured SWCCs from the instrumented site were fitted by van Genuchten model. Previously developed predicted models were also utilized to evaluate the SWCC parameters. Based on the evapotranspiration and rainfall amounts, distinct drying and wetting cycles were recorded. Though hourly data was collected in this study, average daily values were used for the analysis. Unsaturated flow parameters (α, n, m) were determined from both laboratory testing and field moisture-suction data along with the predictive models. Clear differences were observed between the values obtained from predictive models and field generated SWCC. The outcome from this study revealed that field reconstructed SWCCs can be used to simulate higher precision in numerical modeling in numerous geotechnical applications.

The use of the evapotranspiration cover for landfill is increasing because of its long-term enhanced performance. However, the performance of evapotranspiration cover primarily depends on the onsite geo-climatic conditions. Therefore, field verification of cover performance through constructed test plots is required before actual implementation. Additionally, numerical modeling and comparison with field results are necessary for future performance prediction. The objective of this study was to simulate the water balance hydrology of evapotranspiration cover using the code SEEP/W. Drainage lysimeter was constructed with fine-grained soil and native vegetation. Field water balance data from the lysimeter were obtained through instrumentation. Onsite climatological data, laboratory and field investigated soil parameters and actual field studied plant parameters were used as model input. Based on one year’s simulation, it was observed that the code nearly captured the seasonal variations in the water balance quantities measured in the field. Surface runoff was reasonably predicted in the model where precipitation intensity appeared to be responsible to some extent. Evapotranspiration was slightly overpredicted and the fluctuation in soil water storage was similar to the field results. The model predicted annual percolation was approximately 45 mm, which is under-predicted than the actual field measured annual percolation of 62 mm.