INCREASING EFFICIENCY AND SUSTAINABILITY OF WASTE-TO-ENERGY SYSTEMS USING BIOCHAR FOR HYDROGEN SULFIDE CONTROL AND LIFE CYCLE ASSESSMENT

The research aim was to increase energy production efficiency and reduce the environmental impacts of waste-to-energy technologies, specifically anaerobic digestion (AD) of dairy manure (DM) and combustion of poultry litter (PL). The first objective was co-digestion of DM with gummy vitamin waste (GVW) to increase methane (CH4) yield. The GVW co-digestion treatments significantly increased CH4 yield by 126% - 151% compared to DM-only treatment and significantly decreased the H2S concentration in the biogas by 66% - 83% compared to DM-only. The second objective was understanding the effect of hydrogen sulfide (H2S) scrubber management, operation, and maintenance parameters on H2S removal efficiency. Even though the capital and operating costs for the two H2S scrubbing systems in this study were low (< $1500/year), they showed ineffective performance due to insufficient air injection, substitution of proprietary iron oxide-based H2S adsorbents for cheaper alternatives, and the lack of dedicated operators. The third objective was adsorption of H2S using Fe-impregnated biochar as a substitute for activated carbon (AC). Fe-impregnation of biochar led to a 4.3-fold increase in the H2S adsorption capacity compared to AC. When compared to unimpregnated biochars, Fe-impregnation led to an average 3.2-fold increase in the H2S adsorption capacity. The fourth objective was in-situ use of biochar in AD to remove H2S. In-situ biochar addition at the highest dose (1.82 g biochar/g manure total solids (TS)) resulted in an average H2S removal efficiency of 91.2%. Biochar particle size had no significant effect on H2S reduction. In-situ addition of Fe-impregnated biochar resulted in an average H2S removal efficiency of 98.5%. The fifth objective was a life cycle assessment (LCA) of a PL fluidized bed combustion (FBC) system. The LCA assessment showed that heating poultry houses using heat obtained from the combustion of PL in the FBC system had 32% lower climate change potential (CCP) compared to use of propane for heating poultry houses. However, analyzing the FBC system under a net positive electrical output scenario resulted in 66% less impact on CCP and a 48 – 98% reduction in environmental impacts compared to the previous scenario with net electricity input

\tau Polarization asymmetry in B→Xsτ+τ−B \to X_s \tau^+ \tau^- in SUSY models with large tanβtan\beta

Rare B decays provides an opportunity to probe for new physics beyond the standard model. the effective Hamiltonian for the decay $b \to s l^+ l^-$ predicts the characteristic polarization for the final state lepton. Lepton polarization has, in addition to a longitudinal component $P_L$, two orthogonal components $P_T$ and $P_N$ lying in and perpendicular to the decay plane. In this article we perform a study of the $\tau$-polarisation asymmetry in the case of SUSY models with large $\tan\beta$ in the inclusive decay $B \to X_s \tau^+ \tau^-$.Comment: RevTex file, 15 pages (including 6 ps figures). accepted version in Phys. Rev.

Longitudinal Polarization in KL→μ+μ−K_L \to \mu^+ \mu^- in MSSM with large tanβtan\beta

A complete experiment on decay $K_L \to l^+ l^-$ will not only consist of measurement of the decay rates but also lepton polarization etc. These additional observations will yield tests of CP invariance in these decays. In $K_L$ and $K_S$ decays, the e mode is slower than the $\mu$ mode by roughly $(m_e/m_\mu)^2$ \cite{sehgal1}. As well discussed in literature \cite{herczeg} the Standard Model contribution to the lepton polarization is of order $2 \times \sim 10^{-3}$. We show that in MSSM with large \tanbeta and light higgs masses ($\sim 2 M_W$), the longitudinal lepton polarization in $K_L \to \mu^+ \mu^-$ can be enhanced to a higher value, of about $10^{-2}$.Comment: version appeared in Physics Letters B, minor correction

Tricking LLMs into Disobedience: Understanding, Analyzing, and Preventing Jailbreaks

Recent explorations with commercial Large Language Models (LLMs) have shown that non-expert users can jailbreak LLMs by simply manipulating the prompts; resulting in degenerate output behavior, privacy and security breaches, offensive outputs, and violations of content regulator policies. Limited formal studies have been carried out to formalize and analyze these attacks and their mitigations. We bridge this gap by proposing a formalism and a taxonomy of known (and possible) jailbreaks. We perform a survey of existing jailbreak methods and their effectiveness on open-source and commercial LLMs (such as GPT 3.5, OPT, BLOOM, and FLAN-T5-xxl). We further propose a limited set of prompt guards and discuss their effectiveness against known attack types

Unitarity constraints on the stabilized Randall-Sundrum scenario

Recently proposed stabilization mechanism of the Randall-Sundrum metric gives rise to a scalar radion, which couples universally to matter with a weak interaction ($\simeq 1$ TeV) scale. Demanding that gauge boson scattering as described by the effective low enerrgy theory be unitary upto a given scale leads to significant constraints on the mass of such a radion.Comment: 10 page Latex 2e file including 4 postscript figures. Accepted in Journal of Physics

Smartphone assisting convolutional neural networks for soil texture classification in dry and wet humid conditions in West Guwahati, Assam

Soil texture using a hydrometer or pipette method requires expertise, although these are accurate. A soil expert may help the farmer to detect the soil texture by analyzing the visual texture of the soil, which is not always accurate. This paper presents the smartphone image-based sand and clay soil classification in wet and dry humid conditions using Self Convolution Neural Network (SCNN) and finetuned MobileNet.A soil dataset of 576 soil images was prepared using a low-cost smartphone under natural light conditions. Different augmentation techniques such as shift, range, rotation, and zoom were applied to the soil dataset to increase the number of images in the soil dataset. The best performance of the MobileNet was reported at epoch 15 with a testing and training loss of 0.0091 and 0.0194, respectively. Though the SCNN model performed best at epoch 10 with a testing accuracy of 99.85%, the MobileNet reported less computation time (167.8s) than the SCNN (273.2s). The precision and recall of the models were 99.62 (MobileNet) and 99.84 (SCNN). The accuracy of the SCNN reported itself as the best model, whereas the computing time of the MobileNet reported itself as the best model in different humid conditions. The model can be used to replicate the traditional soil texture analysis method and the farmers can use it for better productivity

Methane and Hydrogen Sulfide Production from the Anaerobic Digestion of Fish Sludge from Recirculating Aquaculture Systems: Effect of Varying Initial Solid Concentrations

Recirculating aquaculture systems (RAS) are efficient at solid waste capture and collection but generate a concentrated waste stream. Anaerobic digestion (AD) could be one potential treatment option for RAS facilities. However, the concentration of organic matter in the sludge can significantly affect the biogas quality from AD. This study evaluated the effect of fish sludge (FS) solid concentration on biogas quality. Three FS treatments consisted of different initial total solid concentrations (1.5%, 2.5%, and 3.5%) from a mixture of sludge produced by Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Methane (CH4) production was measured, quantified, and normalized on a volatile solids (VS) basis. The highest solid concentration treatment produced 23% more CH4 than the lowest solid concentration (519 mL/g VS versus 422 mL/g VS, respectively). Peak CH4 production occurred on Day 7 for the lowest FS concentration (78.2 mL/day), while the highest FS concentration peaked on Day 11 (96 mL/day). Peak hydrogen sulfide (H2S) concentrations ranged from 1803&ndash;2074 ppm across treatments, signifying the requirement of downstream unit processes for H2S removal from biogas. Overall, this study demonstrated that increasing the FS concentration can significantly enhance CH4 production without affecting the stability of the digestion process

Evaluation of Hydrogen Sulfide Scrubbing Systems for Anaerobic Digesters on Two U.S. Dairy Farms

Hydrogen sulfide (H2S) is a corrosive trace gas present in biogas produced from anaerobic digestion systems that should be removed to reduce engine-generator set maintenance costs. This study was conducted to provide a more complete understanding of two H2S scrubbers in terms of efficiency, operational and maintenance parameters, capital and operational costs, and the effect of scrubber management on sustained H2S reduction potential. For this work, biogas H2S, CO2, O2, and CH4 concentrations were quantified for two existing H2S scrubbing systems (iron-oxide scrubber, and biological oxidation using air injection) located on two rural dairy farms. In the micro-aerated digester, the variability in biogas H2S concentration (average: 1938 &plusmn; 65 ppm) correlated with the O2 concentration (average: 0.030 &plusmn; 0.004%). For the iron-oxide scrubber, there was no significant difference in the H2S concentrations in the pre-scrubbed (450 &plusmn; 42 ppm) and post-scrubbed (430 &plusmn; 41 ppm) biogas due to the use of scrap iron and steel wool instead of proprietary iron oxide-based adsorbents often used for biogas desulfurization. Even though the capital and operating costs for the two scrubbing systems were low (&lt;$1500/year), the lack of dedicated operators led to inefficient performance for the two scrubbing systems

Methane and Hydrogen Sulfide Production from Co-Digestion of Gummy Waste with a Food Waste, Grease Waste, and Dairy Manure Mixture

Co-digestion of dairy manure with waste organic substrates has been shown to increase the methane (CH4) yield of farm-scale anaerobic digestion (AD). A gummy vitamin waste (GVW) product was evaluated as an AD co-digestion substrate using batch AD testing. The GVW product was added at four inclusion levels (0%, 5%, 9%, and 23% on a wet mass basis) to a co-digestion substrate mixture of dairy manure (DM), food-waste (FW), and grease-waste (GW) and compared to mono-digestion of the GVW, DM, FW, and GW substrates. All GVW co-digestion treatments significantly increased CH4 yield by 126&ndash;151% (336&ndash;374 mL CH4/g volatile solids (VS)) compared to DM-only treatment (149 mL CH4/g VS). The GVW co-digestion treatments also significantly decreased the hydrogen sulfide (H2S) content in the biogas by 66&ndash;83% (35.1&ndash;71.9 mL H2S/kg VS) compared to DM-only (212 mL H2S/kg VS) due to the low sulfur (S) content in GVW waste. The study showed that GVW is a potentially valuable co-digestion substrate for dairy manure. The high density of VS and low moisture and S content of GVW resulted in higher CH4 yields and lower H2S concentrations, which could be economically beneficial for dairy farmers

Methane and Hydrogen Sulfide Production from Co-Digestion of Gummy Waste with a Food Waste, Grease Waste, and Dairy Manure Mixture

Co-digestion of dairy manure with waste organic substrates has been shown to increase the methane (CH4) yield of farm-scale anaerobic digestion (AD). A gummy vitamin waste (GVW) product was evaluated as an AD co-digestion substrate using batch AD testing. The GVW product was added at four inclusion levels (0%, 5%, 9%, and 23% on a wet mass basis) to a co-digestion substrate mixture of dairy manure (DM), food-waste (FW), and grease-waste (GW) and compared to mono-digestion of the GVW, DM, FW, and GW substrates. All GVW co-digestion treatments significantly increased CH4 yield by 126–151% (336–374 mL CH4/g volatile solids (VS)) compared to DM-only treatment (149 mL CH4/g VS). The GVW co-digestion treatments also significantly decreased the hydrogen sulfide (H2S) content in the biogas by 66–83% (35.1–71.9 mL H2S/kg VS) compared to DM-only (212 mL H2S/kg VS) due to the low sulfur (S) content in GVW waste. The study showed that GVW is a potentially valuable co-digestion substrate for dairy manure. The high density of VS and low moisture and S content of GVW resulted in higher CH4 yields and lower H2S concentrations, which could be economically beneficial for dairy farmers.https://doi.org/10.3390/en1223446