Maximum Production Research Articles

Production and Antimicrobial Activities of Pyocyanin Extracts from Pseudomonas aeruginosa

Pyocyanin is a blue-green phenazine pigment synthesized by Pseudomonas aeruginosa that has significant biotechnological applications. The present study aims to investigate pyocyanin extracts of multi-drug resistant P. aeruginosa isolates sourced from hospital wastewater and evaluate their antimicrobial activity against a panel of clinically relevant pathogens such as Staphylococcus aureus, Salmonella typhi, Achromobacter xylosoxidans and Candida albicans. Nutrient broth and King’s A broth supplemented with 1% nutrient supplements such as rice water and groundnut cake powder were used as a production medium. Extracted pyocyanin was confirmed by FTIR analysis. The isolates P8 and P9 demonstrated of varying concentrations of pyocyanin in different media. Isolate P8 showed maximum pyocyanin production in King’s A broth compared to nutrient broth with pyocyanin yields 14.34 (µg/mL) and 5.63 (µg/mL), respectively, without the nutrient supplements. Preliminary antimicrobial activity of the pyocyanin extracts exhibited substantial inhibition of tested bacterial culture at a concentration of 25 mg/µl; however, did not show any antifungal activity against tested fungi.

Log-Concavity with Respect to the Number of Orbits for Infinite Tuples of Commuting Permutations

AbstractLet A(p, n, k) be the number of p-tuples of commuting permutations of n elements whose permutation action results in exactly k orbits or connected components. We formulate the conjecture that, for every fixed p and n, the A(p, n, k) form a log-concave sequence with respect to k. For $$p=1$$ p = 1 this is a well-known property of unsigned Stirling numbers of the first kind. As the $$p=2$$ p = 2 case, our conjecture includes a previous one by Heim and Neuhauser, which strengthens a unimodality conjecture for the Nekrasov–Okounkov hook length polynomials. In this article, we prove the $$p=\infty $$ p = ∞ case of our conjecture. We start from an expression for the A(p, n, k), which follows from an identity by Bryan and Fulman, obtained in the their study of orbifold higher equivariant Euler characteristics. We then derive the $$p\rightarrow \infty $$ p → ∞ asymptotics. The last step essentially amounts to the log-concavity in k of a generalized Turán number, namely, the maximum product of k positive integers whose sum is n.

Process development and optimization of sustainable and integrated large scale ammonia production process using water electrolysis based green hydrogen: Investigating process, energy, economic & environmental perspectives

Ammonia is an important raw material for fertilizer production and significantly contributes globally to agricultural systems. The multi-objective optimization of a large-scale integrated ammonia production process using water electrolysis-based green hydrogen is carried out using the Hybrid Multi-Objective Differential Evolution-Distance Learning Scheme (Hybrid MODE-DLS) algorithm. Three optimization cases are solved with the objectives of ammonia production rate, total production cost, and total energy by considering nine decision variables, and multiple constraints. The maximum ammonia production (66.51 kmol/h) and minimum total production cost (105.07 $/yr × 105) are obtained in Case 1 whereas the minimum energy value (7863.45 kWh) is obtained in Case 2. The minimum heat credit value of 3057300.5 $/annum exists in Case 2 solutions whereas the maximum heat credit value of 7992076 $/annum is seen in Case 3. The ammonia production rate increased by 82.79% in Case 2 results compared to the base case results.

Rethinking Amino Acid Nutrition of Black Soldier Fly Larvae (Hermetia illucens) Based on Insights from an Amino Acid Reduction Trial

Rearing black soldier fly larvae (BSFL) in order to utilize biogenic materials is of increasing interest in the context of sustainable animal production. However, little is known about the amino acid (AA) requirements of this animal species. Therefore, a feeding experiment with BSFL was conducted, in which lysine, methionine, cysteine, arginine, phenylalanine, or histidine was reduced by 65% or methionine was increased by 65%. Reductions in single AAs in the substrate did not negatively impact BSFL growth, while the addition of methionine improved the growth performance, indicating that methionine was a limiting nutritional factor for maximal productivity. Differences in dietary AA profiles had no impact on the AA profile of the BSFL biomass. However, balance calculations for individual AAs indicated that the substrate microbiome was capable of synthesizing and balancing those AAs for microbial protein synthesis. While both the BSFL and microbiome utilized all free AAs, suggesting that supplemental AAs can be effective additives in BSFL production, this microbial AA synthesis avoided the negative performance impacts of BSFL provoked by severe AA reductions. The quantification of these effects suggested that the microbiome could add up to 35% to the overall AA supply in order to overcome AA deficiency. This effect may not necessarily ensure maximal BSFL productivity, as demonstrated by the extra addition of methionine to the substrate. Our research indicated that BSFL nutrition should consider interactions between substrate composition and microbial activity.

Depolymerization of Lignosulfonate Catalyzed by Different Solid Base Oxides to Prepare Phenolic Compounds

Lignin is the most abundant aromatic renewable polymer in nature. However, its very stable structure limits its widespread application. To achieve high-value utilization of lignin, this study used solid base oxides to depolymerize calcium lignosulfonate (CLS) for the synthesis of phenolic compounds. The catalyst precursors were prepared by hydrothermal synthesis, and the corresponding mesoporous metal oxides NiO, MgCoOx, and NiMgCoOx were obtained after calcination. MgCoOx and NiMgCoOx had similar but stronger basicity compared to NiO. While all oxides promoted the depolymerization of CLS, NiMgCoOx was identified as the best catalyst, achieving a maximum liquid product yield of 74.3 wt.% and a selectivity of phenolic compounds of 74.52% in the liquid product. In addition, NiMgCoOx showed satisfactory structural and catalytic stability. The experimental results indicated that solid base oxides can capture the active hydrogen in CLS, causing the hydrolysis reaction of ether bonds, and the resulting products continuously depolymerize or polymerize; Co present in the catalyst promotes the adsorption of hydrogen by Ni, while NiO in NiMgCoOx facilitates the adsorption of both reactants and hydrogen. The combination of Ni and Co improves hydrogenation performance.

DOWN DRAFT GASIFIER TO PRODUCE SYNGAS BY BIO WASTE

Biowaste is a valuable resource for sustainable energy production. Through combustion, it generates thermal energy, while gasification a thermo chemical process which transforms solid fuel into gaseous fuel. This process, specifically through a downdraft gasifier, converts biowaste into a combustible gas known as producer gas. Utilizing biowaste as a fuel source plays a crucial role in reducing dependency on fossil fuels, providing a renewable, low-carbon energy alternative. Combining biowaste with other renewable sources like wind and solar power is an effective solution for small-scale, decentralized power generation. This approach not only meets local electricity needs but also supplies heat for rural development. Optimizing operating conditions and methodologies for maximum syngas production in biomass gasification is essential. The gasification system designed here includes a downdraft biomass thermo chemical conversion gasifier, a gas transport line with tar removal, and a fully enclosed combustion chamber—together, forming a robust setup for efficient, clean energy production. KEY WORD: Downdraft gasifier, biowaste, gasification, pyrolysis, syngas

Dynamic Integrated Scheduling of Production Equipment and Automated Guided Vehicles in a Flexible Job Shop Based on Deep Reinforcement Learning

The high-quality development of the manufacturing industry necessitates accelerating its transformation towards high-end, intelligent, and green development. Considering logistics resource constraints, the impact of dynamic disturbance events on production, and the need for energy-efficient production, the integrated scheduling of production equipment and automated guided vehicles (AGVs) in a flexible job shop environment is investigated in this study. Firstly, a static model for the integrated scheduling of production equipment and AGVs (ISPEA) is developed based on mixed-integer programming, which aims to optimize the maximum completion time and total production energy consumption (EC). In recent years, reinforcement learning, including deep reinforcement learning (DRL), has demonstrated significant advantages in handling workshop scheduling issues with sequential decision-making characteristics, which can fully utilize the vast quantity of historical data accumulated in the workshop and adjust production plans in a timely manner based on changes in production conditions and demand. Accordingly, a DRL-based approach is introduced to address the common production disturbances in emergency order insertions. Combined with the characteristics of the ISPEA problem and an event-driven strategy for handling dynamic events, four types of agents, namely workpiece selection, machine selection, AGV selection, and target selection agents, are set up, which refine workshop production status characteristics as observation inputs and generate rules for selecting workpieces, machines, AGVs, and targets. These agents are trained offline using the QMIX multi-agent reinforcement learning framework, and the trained agents are utilized to solve the dynamic ISPEA problem. Finally, the effectiveness of the proposed model and method is validated through a comparison of the solution performance with other typical optimization algorithms for various cases.

Solid-state anaerobic digestion of sweet corn waste: The effect of mixing and recirculation interval

The mixing and sludge recirculation interval is one of the key successes of the solid-state anaerobic digestion process, a promising technology for converting high-solid agro-industrial wastes to renewable energy. This study employed a pilot-scale completely stirred tank reactor to examine biogas production from sweet corn waste, including corn cobs, husks, and seeds. The reactor was operated as solid-state anaerobic digestion at an ambient temperature. The mixing and recirculating intervals were set to non-mixing and mixing for 10 minutes every 3, 6, and 12 hours. The initial total solid of the feedstock was 25%, while the hydraulic retention time was 30 days. The results showed that during the mixing and recirculation every three hours, the highest chemical oxygen demand, total solid, and volatile solid (VS) removal efficiencies were 85.42%, 62.92%, and 64.59%, respectively. The ratio between volatile fatty acid and alkalinity ranged between 0.20 and 0.30 without any sign of system failure. The highest specific methane yield of 766 L/kg VSadded was obtained in the experiment with mixing and recirculating intervals every 3 hours. It was found that the modified Gompertz model could effectively fit the methane yields with an R2 of 0.9667. The modeled methane production potential and the maximum methane production rate were 867.40 NL/kg VSadded and 132.01 NL/kg VSadded-d, respectively. Additionally, the levelized cost of the biogas produced from the solid-state anaerobic digestion of the sweet corn waste was calculated to be 0.61 USD/kg. The findings of this study can serve as a guide for the design and operation of the SS-AD system, which aims to transform various types of lignocellulosic waste into environmentally friendly energy.

High-performance anisotropic Sm2Co17/Fe(Co) bulk nanocomposite magnets fabricated by two-step high-pressure thermal compression deformation

In the realm of Sm2Co17 nanocomposite magnetic materials, it remains a challenge to fabricate anisotropic magnets by forming nanocrystalline Sm2Co17 phases with strong texture, alongside soft phases of small size and high soft phase content. In this paper, we present a novel approach for fabricating anisotropic Sm2Co17/Fe(Co) nanocomposite bulk magnets with a prominent (00 l) texture of the Sm2Co17 phase, the 25 wt% content of the Fe(Co) phase, and a refined grain size of 25 nm. This fabrication is achieved using a two-step high-pressure thermal compression (HPTC) deformation process. The fabricated magnets exhibit a maximum energy product [(BH)max] of 20.0 MGOe with a pronounced magnetic anisotropy (Br///Br⊥ = 1.23). This result is 53 % higher than the previously reported largest value [(BH)max = 13.1 MGOe] for Sm2Co17-based nanocomposites. The magnets also exhibit a low remanence temperature coefficient (α = −0.014 %/°C) and a low coercivity temperature coefficient (β = −0.23 %/°C), demonstrating exceptional thermal stability. Our findings may improve the fabrication of anisotropic bulk Sm2Co17 nanostructure magnets for practical applications.

Effects of cardiac telerehabilitation during COVID-19 on cardiac hemodynamic and functional responses and quality of life: a randomized controlled trial

Purpose: This study aimed to assess the effects of a home-based cardiac telerehabilitation (HBCT) on cardiac hemodynamic and functional responses and health-related quality (HRQOL) of the patients undergoing percutaneous coronary intervention (PCI). Materials and methods: In this randomized controlled clinical trial, single-blinded. One hundred-fifty-five patients (mean age: 50.41±7.3 years, 41 women and 39 men) who underwent PCI were randomized into the two groups of intervention and control. The HBCT program included supervised exercise training, walking, phone calls, and a pedometer for 8 weeks. Hemodynamic changes, including systolic blood pressure (SBP) and diastolic blood pressure (DBP), resting heart rate (HRrest), maximum heart rate (HRmax), ejection fraction (EF), and rate pressure product (RPP), and functional parameters including the distance walked and metabolic equivalents (METS), also HRQOL were measured in all patients before and after the 8-week HBCT program. Results: Our results showed significant reductions in SBPrest (126.82±9.17 vs. 131.27±10.24; P =0.044), DBPrest (87.4±5.39 vs. 89.17±7.33; P=0.027), HRrest (76.15±3.01 vs. 77.65±4.16; P=0.041), HRmax (143.1±5.24 vs. 147.57±8.63; P=0.011), and RPP (9.64±0.81 vs. 10.07±0.99; P=0.007) and significant elevations in (45.75±4.31 vs. 43.5±5.21; P=0.039), distance walked (514.95±214.5 vs. 368.04±221.43; P=0.019), Mets (7.41±0.84 vs. 6.89±1.28; P=0.018), as well as HRQOL in the MCS (50.62±10.45 vs. 46.25±7.74; P=0.037), and HRQOL in the PCS (46.75±8.73 vs. 42.37±9.99; P=0.040) in the intervention group compared to the control group. Conclusion: An HBCT program consisting of supervised exercise training significantly improved hemodynamic response, exercise performance capacity, and HRQOL in patients following PCI.

Biofilm mass transfer and thermodynamic constraints shape biofilm in trickle bed reactor syngas biomethanation

Syngas (H2, CO2, CO) produced thermochemically from lignocellulosic biomass is an underexploited source for resource recovery and valorisation through its biological conversion for the production of a wide range of chemicals and fuels. Syngas biomethanation is one such promising bioconversion pathway, displaying interesting features such as high conversion efficiency and product selectivity, as methane is the sole product of the process. The biological conversion of syngas to high purity biomethane is still typically associated with a number of challenges related to the syngas composition, CO toxicity, and gas–liquid mass transfer limitations. In this work, the syngas biomethanation process carried out in trickle bed reactors was investigated at its boundary conditions to explore the limits of the process, focusing on syngas composition and mass-transfer conditions potentially limiting process performance. The process was found to be robust when exposed to CO excess, but highly sensitive to H2 excess, which caused severe inhibition even under small amounts of excess H2. This implies that biomethane purity comparable to natural gas can be achieved by addition of renewable H2, but this requires precise control to avoid process failure. Modulating the liquid recirculation rate and gas residence time allowed for a maximum methane productivity of 9.8 ± 0.5 mmol CH4 h−1 Lreactor−1 with full conversion of H2 and CO at a gas residence time of 1 h. Nevertheless, increasing the gas–liquid mass transfer with increasing liquid recirculation rate did not lead to increased methane productivity, which suggested additional rate-limiting bottlenecks in the process. Careful investigation of other factors potentially limiting the process led to the conclusion that diffusive transport of syngas components in the biofilm was the main bottleneck of the process. This diffusive limitation leads to a scenario of severe substrate scarcity in the biofilm phase that conditions the thermodynamic feasibility of the different biochemical reactions involved in syngas biomethanation. In turn, these thermodynamic constraints were found to drive the stratification of microbial groups and sequential consumption of syngas components along the height of the reactor

Performance of a pilot-scale microbial electrolysis cell coupled with biofilm-based reactor for household wastewater treatment: simultaneous pollutant removal and hydrogen production.

The septic tank is the most commonly used decentralized wastewater treatment systems for household wastewater treatment in on-site applications. The removal rate of various pollutants is lower in different septic tank configurations. The integration of a microbial electrolysis cells (MEC) into septic tank or biofilm-based reactors can be a green and sustainable technology for household wastewater treatment and energy production. In this study, a 50-L septic tank was converted into a 50-L MEC coupled with biofilm-based reactor for simultaneous household wastewater treatment and hydrogen production. The biofilm-based reactor was integrated by an anaerobic packed-bed biofilm reactor (APBBR) and an aerobic moving bed biofilm reactor (aeMBBR). The MEC/APBBR/aeMBBR was evaluated at different organic loading rates (OLRs) by applying voltage of 0.7 and 1.0V. Result showed that the increase of OLRs from 0.2 to 0.44kg COD/m3 d did not affect organic matter removals. Nutrient and solids removal decreased with increasing OLR up to 0.44kg COD/m3 d. Global removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), ammoniacal nitrogen (NH4+), total phosphorus (TP) and total suspended solids (TSS) removal ranged from 81 to 84%, 84 to 85%, 53 to 68%, 88 to 98%, 11 to 30% and 76 to 88% respectively, was obtained in this study. The current density generated in the MEC from 0 to 0.41 A/m2 contributed to an increase in hydrogen production and pollutants removal. The maximum volumetric hydrogen production rate obtained in the MEC was 0.007 L/L.d (0.072 L/d). The integration of the MEC into biofilm-based reactors applying a voltage of 1.0V generated different bioelectrochemical nitrogen and phosphorus transformations within the MEC, allowing a simultaneous denitrification-nitrification process with phosphorus removal.

The Complement Factor H (Y402H) risk polymorphism for age-related macular degeneration affects metabolism and response to oxidative stress in the retinal pigment epithelium

Age-related macular degeneration (AMD), the leading cause of central vision loss in the elderly, involves death of the retinal pigment epithelium (RPE) and light-sensing photoreceptors. This multifactorial disease includes contributions from both genetic and environmental risk factors. The current study examined the effect of the Y402H polymorphism of Complement Factor H (CFH, rs1061170) and cigarette smoke, predominant genetic and environmental risk factors associated with AMD. We used targeted and discovery-based approaches to identify genotype-dependent responses to chronic oxidative stress induced by cigarette smoke extract (CSE) in RPE differentiated from induced pluripotent stem cells (iPSC) derived from human donors harboring either the low risk (LR) or high risk (HR) CFH genotype. Chronic CSE altered the metabolic profile in both LR and HR iPSC-RPE and caused a dose-dependent reduction in mitochondrial function despite an increase in mitochondrial content. Notably, cells with the HR CFH SNP showed a greater reduction in maximal respiration and ATP production. Significant genotype-dependent changes in the proteome were observed for HR RPE at baseline (cytoskeleton, MAPK signaling) and after CSE exposure, where a less robust upregulation of the antioxidants and significant downregulation in proteins involved in nucleic acid metabolism and membrane trafficking were noted compared to LR cells. In LR cells, uniquely upregulated proteins were involved in lipid metabolism and chemical detoxification. These genotype-dependent differences at baseline and in response to chronic CSE exposure suggest a broader role for CFH in modulating the response to oxidative stress in RPE and provides insight into the interaction between environmental and genetic factors in AMD pathogenesis.

H2-Rich Gas Production from Gasification of Oily Sludge via Supercritical Water Technology: Synergy Effect of KOH, K2CO3, and Reaction Parameters

Yielding H2 as a sustainable gaseous fuel from oily sludge is of critical importance in mitigating the environmental effects linked with the usage of conventional fossil fuels. The deficiency in the drying of biomass has ensued to the exploration of supercritical water gasification (SCWG) as an effective method for harvesting H2-rich gas. This study utilized a combination of two alkali catalysts (KOH and K2CO3) in supercritical water to generate a H2-rich gas from a conventional oily sludge. The Box-Behnken design was utilized to assess the impact of different operational variables, including temperature (400-600°C), feed concentration (FC) (between 5 and 25 wt.%), residence time (RT) (15-45 min), and catalyst to feed mass ratios (FMR) (0-0.50). The maximum production of H2 at 3.22 mmolg-feed-1 was achieved under optimal conditions of 600°C, 32.76 min, and a KOH to FMR of 0.45 and K2CO3 to FMR of 0.28.

Potassium Fertilization Alters the Morphogenetic, Structural, and Productive Characteristics of Panicum maximum Cultivars

The objective was to evaluate the effects of potassium fertilization on the morphogenetic, structural, and productive characteristics of Panicum maximum (cvs. Tanzania, Quênia, Mombaça, Zuri, Massai, and Tamani). The design was in randomized blocks with four doses of potassium (K) 0, 205, 410, and 820 mg dm−3, divided into 5 applications. The analyzed variables were leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), leaf senescence rate (LSR), leaf life span (LLS), phyllochron (PC), number of live leaves (NLL), final leaf length (FLL), tiller population density (TPD), and forage mass (FM). LAR increased by 0.00216 leaves tiller on day-1 (p = 0.0354) and LER increased by 0.00980 cm tiller on day-1 for each milligram of K (p = 0.0402). There was an increase in FLL of 0.16, 0.08, and 0.07 days for the cultivars Mombaça, Massai, and Tamani, respectively, for each milligram of K applied (p = 0.0034). The TPD of the cultivar Tamani increased linearly by 0.074 tillers/pot for each milligram of K (p = 0.0226), and the cultivar Massai showed a quadratic behavior. The TPD of the other cultivars was not influenced by the increase in the K doses. For forage mass (FM), the cultivars Mombaça and Quênia increased by 0.16 and 0.39 g DM/pot for each milligram of K added to the soil. The cultivars Tanzânia, Zuri, Massai, and Tamani showed maximum point at doses of 261.35, 279.45, 300.57, and 275.86 mg dm−3 K, respectively. Potassium fertilization linearly increased leaf appearance and elongation, with maximum productivity reached at a K dose of 430 mg dm−3, except for the cultivars Mombaça and Quênia, which responded up to a K dose of 820 mg dm−3.

Transcriptomics-guided optimization of vitamins to enhance erythromycin yield in saccharopolyspora erythraea

Comparative transcriptomics uncovered distinct expression patterns of genes associated with cofactor and vitamin metabolism in the high-yielding mutant strain Saccharopolyspora erythraea HL3168 E3, as compared to the wild-type NRRL 2338. An in-depth analysis was conducted on the effects of nine vitamins, and it was determined that thiamine pyrophosphate (TPP), vitamin B2, vitamin B6, vitamin B9, vitamin B12, and hemin are key enhancers in erythromycin production in E3, increasing the erythromycin titer by 7.96–12.66%. Then, the Plackett-Burman design and the path of steepest ascent were applied to further optimize the vitamin combination for maximum production efficiency, enhancing the erythromycin titer in shake flasks by 39.2%. Otherwise, targeted metabolomics and metabolic flux analysis illuminated how vitamin supplementation modulates the central carbon metabolism with notable effects on the TCA cycle and methionine synthesis to augment the provision of energy and precursors essential for erythromycin synthesis. This work highlights the capacity for precise vitamin supplementation to refine metabolic pathways, thereby boosting erythromycin production, and provides valuable directions for application on an industrial scale.Graphical

Crystallographic Orientation of Grains Formed in the Laser Melt-Pool of (CoCuFeZr)17Sm2 Anisotropic Permanent Magnets

Textured microstructures and anisotropic properties are key factors for the optimization of magnetic materials. Only for high texture grades can the remanence Jr and the maximum energy product (BH)max be maximized. In additive manufacturing such as laser powder bed fusion (PBF-LB), methods to achieve texture have to be developed. In this work, anisotropic (CoCuFeZr)17Sm2 sintered magnets have been used as a substrate in experiments featuring single laser tracks to study the relationships between crystallographic orientation of the substrate grains and crystallographic orientation of grain growth in the melt-pool. The <0001> crystal direction (c-axis) of the substrate has been systematically varied with respect to the orientation of the laser scan track on the specimen surface. Crystallographic orientations of the melt-pool and the substrate have been analyzed using electron backscatter diffraction (EBSD). It is found that if the c-axis is oriented perpendicular to the temperature gradient in the melt-pool, grains grow with orientation similar to that of the substrate grain. If the c-axis and the temperature gradient are oriented in the same direction, the grains grow with high misorientation to the substrate. The highest anisotropy in the melt-pool is achieved when the substrate’s c-axis is oriented along the laser scan track. Under these conditions, 98.7% of the melt-pool area shows a misorientation <45° compared to the substrate orientation. The texture grade of the melt-pool area is comparable to that of the substrate magnet, at 91.8% and 92.2%, respectively.

Performance Monitoring of Greenhouse Biogas Digester

The country of South Africa is facing an energy crisis due to heavy reliance on fossil fuels, resulting in continuous load shedding. The use of renewable energy technologies can help resolve the current electricity crisis in the country. Moreover, waste-to-energy conversion has the potential to greatly contribute to economic development and improve public health. One such technology is biomass, which exploits waste-to-energy conversion. Additionally, solar energy can be utilized to maintain appropriate digester temperatures for optimal biogas yield. The study aims to assemble a portable balloon biogas digester in an enclosed greenhouse cavity and feed it with cow dung. Daily monitoring of pH and temperature (ambient, greenhouse, and slurry) was conducted, while biogas yield was monitored using a serial residential diaphragm flow meter. Furthermore, the composition of methane was monitored using the SAZQ biogas analyzer. The study investigated the impact of temperature on biogas production. The results revealed that the gas production rate of biogas fermentation increased within a certain temperature range. Therefore, maximum biogas production was achieved at a pH of 6.84 to 7.03, and the composition of methane exceeded 50%. Consequently, the study concluded by indicating that the digester housed within a greenhouse envelope, as demonstrated in this novel study, maintains the temperature within the optimal mesophilic range necessary for anaerobic digestion.

Analyzing Cancer Survival Times Using the Exponentiated Fréchet-Gompertz Distribution

Understanding the survival of cancer patients is essential for determining optimal treatment strategies. This research introduces a robust distribution for analyzing survival data known as the Exponential Fr ́echet-Gompertz distribution (EFG). The EFG combines the unique characteristics of the Exponential Fr ́echet and Gompertz distributions, enhancing its efficiency and providing greater flexibility in representing complex datasets. The study specifically investigates the EFG distribution’s effectiveness in modeling cancer patients’ survival times. A comprehensive analysis of the distribution’s properties is presented, including the quantile and quartile functions, shape indices, moments, moment-generating function, characteristic function, mean residual life, mean waiting time, R ́enyi entropy, and order statistics. The parameters of the distribution are derivedusing five distinct methods: Maximum Likelihood Estimation (MLE), Ordinary Least Squares (OLS), Weighted Least Squares (WLS), Cram ́er-von Mises (CVM), and Maximum Product of Spacings (MPS). A Monte Carlo simulation technique is employed to evaluate the performance of these estimation methods. The simulation results indicate that as sample size increases, the meansquare error (MSE) values for all estimators decrease. Notably, the MLE exhibits the lowest MSE, while the MPS has the highest MSE, particularly for smaller sample sizes. Furthermore, the study presents a comprehensive comparison of the effectiveness of these estimation methods in analyzing survival times for various cancer types, including bladder, bone, blood and brain cancer. The results indicate that the EFG distribution is an optimal model for representing the survival times of patients across these different cancers data. Furthermore, the W.LS method yielded superior estimations for most datasets concerning cancer patient survival. Overall, the EFG distribution demonstrates exceptional capability in accurately fitting survival times for cancer patients compared to other competing distributions.

Optimization of Hydrogen Production System Performance Using Photovoltaic/Thermal-Coupled PEM

A proton exchange membrane electrolyzer can effectively utilize the electricity generated by intermittent solar power. Different methods of generating electricity may have different efficiencies and hydrogen production rates. Two coupled systems, namely, PV/T- and CPV/T-coupling PEMEC, respectively, are presented and compared in this study. A maximum power point tracking algorithm for the photovoltaic system is employed, and simulations are conducted based on the solar irradiation intensity and ambient temperature of a specific location on a particular day. The simulation results indicate that the hydrogen production is relatively high between 11:00 and 16:00, with a peak between 12:00 and 13:00. The maximum hydrogen production rate is 99.11 g/s and 29.02 g/s for the CPV/T-PEM and PV/T-PEM systems. The maximum energy efficiency of hydrogen production in CPV/T-PEM and PV/T-PEM systems is 66.7% and 70.6%. Under conditions of high solar irradiation intensity and ambient temperature, the system demonstrates higher total efficiency and greater hydrogen production. The CPV/T-PEM system achieves a maximum hydrogen production rate of 2240.41 kg/d, with a standard coal saving rate of 15.5 tons/day and a CO2 reduction rate of 38.0 tons/day. Compared to the PV/T-PEM system, the CPV/T-PEM system exhibits a higher hydrogen production rate. These findings provide valuable insights into the engineering application of photovoltaic/thermal-coupled hydrogen production technology and contribute to the advancement of this field.