Four-step Cycle Research Articles

Investigation of the flash vaporization technique as a novel anolyte separation method in a copper-chlorine thermochemical cycle for sustainable hydrogen production

Thermochemical water-splitting processes are a promising alternative to the conventional hydrogen production technologies. In this regard, the thermochemical copper-chlorine cycle is amongst the clean hydrogen production processes that have shown immense promise to achieve commercialization in the long term future through several investigations reported in the open literature. A primary reason for this is its moderate temperature requirements which can be harnessed through a wide variety of sources such as waste heat or solar thermal energy. More specifically, the four-step variant of the copper-chlorine cycle has exhibited the highest efficiencies compared to its three and five-step versions. However, certain aspects of the cycle need further attention. One such aspect is the fourth and the final step of the cycle – the anolyte separation step which ensures the complete replenishment of all chemical compounds within the cycle. The anolyte is a homogeneous solution that constitutes water, hydrochloric acid, copper (II) chloride, and copper (I) chloride. The existing methodology for the separation of all these chemicals considers a multi-step drying process that takes place at ambient pressure and temperatures over 100°C. These conditions have been concluded to contribute to lowering the energy efficiency and increasing the cost rate of hydrogen through various studies previously conducted and published by the authors. In this regard, the authors have investigated an alternative technique for the anolyte separation process – the flash vaporization method where the partial separation of various chemical species can be achieved under vacuum conditions resulting in lower required temperatures and ultimately making the anolyte separation process relatively less energy intensive. Thus, this paper develops a stand-alone experimental set-up to investigate the flash vaporization process on a lab scale to determine its feasibility and potential to be a replacement for the existing approach of anolyte separation in a four-step copper-chlorine thermochemical cycle. The experiments are conducted under a wide variety of conditions and the obtained results are quite promising. Further, this study also considers the development of an empirical model to enable an analytical quantitative prediction of the separated anolyte solution.

Experimental study of four-step thermal swing adsorption cycle to upgrade biogas obtained from anaerobic digestion

Biogas is a renewable source of energy that when upgraded can be adopted as a reliable and sustainable alternative. This study evaluates the performance of thermal swing adsorption technology applying resistive heating, in upgrading biogas obtained from anaerobic digestion to biomethane. Commercial coconut shell-based activated carbon was used as an adsorbent in the four-step cycle process to capture carbon dioxide, using a fabricated adsorption model. The influence of minor gas constituents of biogas in carbon dioxide breakthrough curves was analyzed. Dynamic adsorption tests were carried out to evaluate the system performance in carbon dioxide capture. The maximum regeneration temperature of 60 ℃ was found to have peak carbon dioxide concentration of 39% in the waste gas, maximum energy requirements of 0.1538kWh per cycle, and an energy efficiency of 87%. This is a good trade-off between adsorbent recovery and system energy efficiency. The adoption of thermal swing adsorption technology in biogas upgrading systems is a viable alternative for water-deficient regions.

Thermodynamic performance assessment of the four-step copper-chlorine cycle in hydrogen production and compression

Rapidly increasing global energy demands requires sustainable alternatives to conventional fossil fuels. Hydrogen emerges as a promising energy carrier due to its high energy density and minimal environmental impact, mainly when produced via thermochemical cycles like the Copper Chlorine (CuCl), which makes use of low-grade waste thermal energy for hydrogen production in an environmentally friendly manner. This study integrates hydrogen production using the Cu-Cl cycle and hydrogen compression systems crucial for establishing robust hydrogen infrastructure. Following hydrogen generation, the study examines the thermodynamic analysis of compressing hydrogen to higher pressures. Parametric variations in compression, including inlet and outlet pressures and the number of stages, are analyzed to optimize energy efficiency and exergy performance. Energy efficiency of around 47.05% is obtained for the 4-step Cu-Cl cycle. The integrated step showed a notably high exergy efficiency of 98.48%. Other key findings include a 35% increase in energy efficiency with five compression stages for an inlet pressure increment from 15 to 30 bars, and a 12% efficiency decrease when varying outlet pressure from 500 to 800 bars. Exergy efficiency shows a 17% improvement with increased compression stages under constant inlet pressure but a 4% decline when varying outlet pressure with a five-stage configuration. These findings highlight the critical role of efficient compression systems in enhancing hydrogen storage and distribution for sustainable energy applications.

Joint Antenna Scheduling and Power Allocation for Multi-Target Tracking under Range Deception Jamming in Distributed MIMO Radar System

The proliferation of electronic countermeasure (ECM) technology has presented military radar with unprecedented challenges as it remains the primary method of battlefield situational awareness. In this paper, a joint antenna scheduling and power allocation (JASPA) scheme is put forward for multi-target tracking (MTT) in the distributed multiple-input multiple-output (D-MIMO) radar. Aiming at radar resource scheduling in the presence of range deception jamming (RDJ), the false target discriminator is designed based on the Cramer–Rao lower bound (CRLB) in terms of the spoofing range, and the predicted conditional CRLB (PC-CRLB) plays a role in evaluating tracking accuracy. The JASPA scheme integrates the quality of service (QoS) principle to develop an optimization model based on false target discrimination, with the objective of enhancing both the discrimination probability of false targets and the tracking accuracy of real targets concurrently. Since the optimal variables can be separated in constraints, a four-step optimization cycle (FSOC)-based algorithm is developed to solve the multidimensional non-convex problem. Numerical simulation results are provided to illustrate the effectiveness of the proposed JASPA scheme in dealing with MTT in the RDJ environment.

The challenge of generating lasting mucosal anti-viral sterilising immunity

The challenge of generating lasting mucosal anti-viral sterilising immunity Achieving sterilising immunity is often challenging and sometimes even impossible. This article gives a glimpse into the concepts behind and highlights some recent advances and challenges. In its essence, sterilising immunity describes the removal of a virus from the host before it can replicate, and this kind of immunity would be the preferred outcome for vaccination as it efficiently limits the infection of the individual and the spread of disease within the community. A typical viral infection goes through a four-step cycle: first, the virus attaches to and enters a host cell; second, it copies its genetic material; third, it assembles new viral particles; and finally, it detaches to infect new cells. In its most straightforward form, sterilising immunity is achieved by the neutralisation of the infectious potential in the first step, (Wahl and Wardemann, Immunity, 2022) followed by their removal.

AI Literacy for Hispanic-Serving Institution (HSI) Students

Degree completion rates for Hispanic students lag far be-hind their white non-Hispanic peers. To close this gap and accelerate degree completion for Hispanic students at Hispanic-Serving Institutions (HSIs), we offer a pedagogical framework to incorporate AI Literacy into existing programs and encourage faculty-mentored undergraduate research initiatives to solve real-world problems using AI. Using a holistic perspective that includes experience, perception, cognition, and behavior, we describe the ideal process of learning based on a four-step cycle of experience, reflecting, thinking, and acting. Additionally, we emphasize the role of social interaction and community in developing mental abilities and understand how cognitive development is influenced by cultural and social factors. Tailoring the content to be culturally relevant, accessible, and engaging to our Hispanic students, and employing projects-based learning, we offer hands-on activities based on social justice, inclusion, and equity to incorporate AI Literacy. Furthermore, combining the pedagogical framework along with faculty-mentored undergraduate research (the significance of which has been shown to have numerous benefits) will enable our Hispanic students develop competencies to critically evaluate AI technologies, communicate and collaborate effectively with AI, and use AI as a tool anywhere; preparing them for the future and encouraging them to use AI ethically.

A comparative exergoenvironmental assessment of thermochemical copper-chlorine cycles for sustainable hydrogen production

Hydrogen is one of the highly promising clean solutions to address the concerns of energy security in the future given the rapid rate of depletion of naturally occurring hydrocarbon sources. However, it is of immense importance that hydrogen is obtained through sources that ensure sustainability. Thermochemical water-splitting processes are among such routes of hydrogen production that are both sustainable and environmentally benign. Thus, this study focuses on assessing the copper-chlorine thermochemical cycles that are among the more promising cycles of the chlorine family in terms of efficiency and cost-effectiveness. Moreover, this study considers a comparative exergoenvironmental evaluation of the four variants of the copper-chlorine cycle that vary in the number and the nature of steps. A comparison in this regard is carried out between the various steps of each cycle in terms of the component-associated environmental impact rates and environmental impact rates of energy transfer as well as the overall environmental impacts of all cycles. In addition, a comparison of the global warming potential of hydrogen synthesized through utilizing various electricity sources is also performed. Based on our evaluations, hydrolysis and electrolysis are the common steps in the five-step cycle, the four-step cycle, and the three-step cycle configuration 1 yielding the highest component-associated environmental impact rates and environmental impact rates of energy transfer, respectively. Conversely, in the three-step cycle configuration 2, the electrolysis and thermal decomposition steps yield the highest corresponding values, respectively. In addition, the three-step cycle configuration 2 (4,869 mPts/h) and the five-step cycle (3,194 mPts/h) have the highest and the lowest component-associated environmental impact rates, respectively while the five-step (530,694 mPts/h) and the four-step (248,050 mPts/h) cycles result in the highest and the lowest environmental impact rates of energy transfer, respectively.

INCORPORATING MIND MAPPING INTO THE INSTRUCTION OF TEACHING WRITING PROCEDURE TEXTS AT SMKN 1 DEDAI

This study explores the effectiveness of the Mind Mapping technique in enhancing students' writing abilities and their active participation in learning activities, specifically in Class X Multimedia of SMKN 1 Dedai. Drawing on various theories of writing instruction and motivation, as well as the benefits of Mind Mapping, the research aims to address students' writing challenges through innovative teaching methodologies.Utilizing Classroom Action Research (CAR) as the methodological framework, the study follows a four-step cycle: Planning, Action, Observing, and Reflecting. Researchers actively engage in teaching writing procedures using the Mind Mapping technique, while observing student interactions and responses in the classroom. Data collection involves observations, tests, field notes, and interviews conducted across two research cycles.The findings reveal significant improvements in student engagement and writing proficiency throughout the research process. Despite initial challenges, such as low motivation and participation, the implementation of the Mind Mapping technique leads to notable enhancements in student participation rates, writing skills, and overall learning experiences.Analysis of data from both cycles demonstrates a marked increase in student participation, with average scores rising from 69.21% to 82.89%. Moreover, test results indicate substantial advancements in students' writing proficiency, particularly in content, organization, language use, vocabulary, and mechanics. This study underscores the importance of innovative teaching methodologies, such as Mind Mapping, in fostering student engagement and improving learning outcomes. By actively integrating such techniques into classroom instruction, educators can create dynamic learning environments conducive to student participation and skill development. Keywords: Mind mapping technique, teaching writing, procedure text

A study on integrated HTR-PM driven hydrogen production using thermochemical cycles

This present study aims to design a nuclear-based hydrogen production system by using the three- and four-step magnesium-chloride cycles, and compares the three-step magnesium-chloride cycle integrated nuclear-based system and the four-step magnesium-chloride cycle integrated nuclear-based system. Within the scope of this study, four units of high-temperature gas-cooled-pebble bed modular nuclear reactor are employed, where a total of 1 GW thermal energy (heat) is secured from these four reactors. All of the heat generated by the reactors is used to drive the power generation and hydrogen production cycles. The proposed system, along with its cycles and processes, are examined by using mass, energy, entropy, and exergy balance equations. The modeling and simulations for the three- and four-step magnesium-chloride cycles are carried out via the Aspen Plus software package. The results are compared for two hydrogen production methods, and sensitivity analysis is assessed for various steam/MgCl2 ratios, as well as different reactor temperatures and pressures for each reaction in the cycles. While the three-step magnesium-chloride cycle integrated nuclear-based system produces 2.43 kg/s hydrogen, 2.13 kg/s hydrogen is produced by the four-step magnesium-chloride cycle integrated nuclear-based system. As a consequence of this present study, energy and exergy efficiencies are calculated as 54.2% and 60.9% for the three-step magnesium-chloride cycle, while these values are 48.0% and 54.0% for the four-step magnesium-chloride cycle. Additionally, while the energy and exergy efficiencies of the three-step magnesium-chloride cycle integrated overall system are 29.2% and 40.3%, these values are 25.6% and 35.2% for the four-step magnesium-chloride cycle integrated system, respectively.

Oxygen-evolving photosystem II structures during S1–S2–S3 transitions

Photosystem II (PSII) catalyses the oxidation of water through a four-step cycle of Si states (i = 0–4) at the Mn4CaO5 cluster1–3, during which an extra oxygen (O6) is incorporated at the S3 state to form a possible dioxygen4–7. Structural changes of the metal cluster and its environment during the S-state transitions have been studied on the microsecond timescale. Here we use pump-probe serial femtosecond crystallography to reveal the structural dynamics of PSII from nanoseconds to milliseconds after illumination with one flash (1F) or two flashes (2F). YZ, a tyrosine residue that connects the reaction centre P680 and the Mn4CaO5 cluster, showed structural changes on a nanosecond timescale, as did its surrounding amino acid residues and water molecules, reflecting the fast transfer of electrons and protons after flash illumination. Notably, one water molecule emerged in the vicinity of Glu189 of the D1 subunit of PSII (D1-E189), and was bound to the Ca2+ ion on a sub-microsecond timescale after 2F illumination. This water molecule disappeared later with the concomitant increase of O6, suggesting that it is the origin of O6. We also observed concerted movements of water molecules in the O1, O4 and Cl-1 channels and their surrounding amino acid residues to complete the sequence of electron transfer, proton release and substrate water delivery. These results provide crucial insights into the structural dynamics of PSII during S-state transitions as well as O–O bond formation.

Heat utilized pressure swing distillation (PSD) process for the separation of the maximum boiling azeotrope HCl and Water in the Cu-Cl Cycle

The four-step copper-chlorine cycle is utilized for hydrogen production from water. Intermediate copper and chlorine compounds facilitate the process, while all other reactants are regenerated and recycled, forming a closed-loop system. Hydrolysis of CuCl2, leading to the formation of Cu2OCl2 and dilute HCl, is a crucial step that uses a large excess of steam to ensure completion of reaction leading to the formation of dilute hydrochloric acid which needs to be recycled for the electrolysis reaction, requiring removal of the azeotrope between HCl and water. This study explores the utilization of pressure swing distillation (PSD) for concentrating HCl above azeotropic composition. Separation of the aqueous mixture of HCl and water using PSD is optimized using a sequential iterative optimization technique, focusing on process intensification. Integration of a simple heat-utilized FE-Process results in a reduction of TAC and energy cost (4.27% TAC and 7.20% energy cost) compared to the process without heat integration. A higher feed composition of HCl (8 mol %) leads to savings of ∼ 38.75% in TAC and a reduction of 53.06% in CO2 emissions compared to a lower feed composition (2.53 mol % HCl). The heat-utilized FE-Process with a higher feed composition is more economically viable for the separation of HCl and water.

Completing the Sexual Response Cycle Three Times a Week Can Improve Whole Body Health

Completing the sexual response cycle can improve individual whole-body wellness. While humans are born with the innate essential of completing the sexual response cycle (orgasm), a lack of education and generational bias has kept orgasm in a fog of shame and guilt. After twelve years of personal research and study on the process and pleasure of the human orgasm, it has led me to support the existing studies of human orgasm that report the bodies’ whole-body benefits of the phases of the orgasm. How the human is stimulated to orgasm is less important than the existence of arousal and the intensity of the climax. There are four primary phases of the sexual response cycle developed by William Masters and Virginia Johnson and published in their 1966 book: Human Sexual Response. Through research, they created a four-step cycle that begins with excitement/attraction, and continues through a plateau, the orgasm and resolution process. There is much research conducted that supports their findings.

Exergoeconomic performance evaluation of three, four, and five-step thermochemical copper-chlorine cycles for hydrogen production

Thermochemical water-splitting processes are among the most promising options for producing sustainable and green hydrogen due to being extremely environmentally benign. Being extensively investigated in the literature, the thermochemical copper-chlorine cycle has demonstrated much promise in this regard as one of the most efficient options for thermochemically obtaining hydrogen. Thus, this study focuses on investigating the exergoeconomic performances of the different variants of the copper-chlorine cycle including the three-, four-, and five-step versions. All cycles are modeled and simulated in Aspen-plus software by considering a recovery of thermal energy from industrial waste flue gases in addition to internal heat recovery. Moreover, a hydrogen production capacity of 668 kg/h is considered for all cycles. The Specific Exergy Costing methodology is employed to study the exergoeconomic performance of each cycle. All cycles are initially examined in terms of the cost rates of energy transfer and hourly levelized cost rates for each step. The cycle variants are further examined through a comparative assessment of several performance parameters including hydrogen cost rates, overall cost rates of energy transfer, and overall hourly levelized cost rates. According to the performed analyses, the three-step variant of the cycle that constitutes a high-temperature electrolysis process produces hydrogen at the lowest cost rate (0.83 $/kg) while the four-step cycle produces hydrogen at the highest cost rate (1.82 $/kg). Furthermore, the hydrolysis step is found to have the highest hourly levelized cost rates for all variants of the cycle. Several factors that impact the hydrogen cost rate are also examined comprehensively. In addition, the extent to which the hydrogen cost rate is sensitive to those factors is discussed.

Studying on the psychological contract of farmers behavior of transferring agricultural land in China

BackgroundAt present, the social economy is in a period of fast-paced change in China, with various modes of production and life evolving and emerging. The transfer of agricultural land is the transformation of the utilization mode of the main factors of production in rural areas, and it is one of the contents of the social and economic reform in rural areas. In 2021, the area of rural land transfer is up to 3.7×1011 m2 in China, an increase of 4.3% over the previous year. 1,239 counties (cities, districts) and 18,731 townships have established agricultural land management rights transfer centers to provide services such as policy consultation, information release, and contract signing for both sides of the transfer. Farmers are the subjects of agricultural land management and transfer. Their behaviors are affected by their psychology to some extent. In the long-term, dynamic, and gradual process of agricultural land transfer, it is particularly important to respect farmers’ wishes, pay attention to farmers’ psychology, and guide farmers’ behavior. However, only a few written contracts were signed. Most are verbal agreements of spontaneous or collective land transfers. The verbal agreements auto-execute to some extent within certain limits. The goals of farmers in farmland transfer are diversified, and their cognition, willingness and psychological identity affect the performance of the contract and the effect of transfer.Subjects and MethodsThe psychological contract of agricultural land transfer can be defined as the transferor and transferee of agricultural land transfer. Through a certain psychological suggestion mode, through the subjective cognition and understanding of the rights and obligations of both parties, rather than the direct explicit expression, a contract relationship of rights and obligations is formed. The party awarding contract and the contractor are the subjects of agricultural land transfer. Therefore, the subjects of the psychological contract of agricultural land transfer include farmers, village collectives and enterprises, all of whom have equal status, forming their own psychological contracts. The forming process of the psychological contract of agricultural land transfer includes four steps. Step one is cognition and judgment. Both parties to the transfer are aware of and judge their own rights and obligations based on external environmental information and their own circumstances. Step two is psychological expectations. Before information is transmitted, both sides of the transmission transform cognition and judgment into psychological expectations. The third step is to convey psychological expectations. Both sides of transfer transmit psychological expectations by means of direct patterns, such as oral form and written form, and implicit ways, such as perception and comprehension. Step four is the formation of the psychological contract. Both sides of transfer reciprocally admit information of psychological expectations transmitted in implicit ways, forming psychological contracts. If they can’t come to an agreement on psychological contracts, a new four-step cycle is entered.ResultsThe forming of the psychological contract of agricultural land transfer is shown in Figure 1. First, farmers’ behavior background, such as the experiences of land lease and transfer, the targets of land transfer and education, has an effect on the building of psychological contracts and its type. On the one hand, the farmers who have the experience of land transfer and get high benefits from it are much more motivated than those who don’t have that experience or ever have dissension while transferring. On the other hand, the targets of transfer and the education level of farmers affect the type of psychological contracts. Second, Farmers’ subjective norms, mainly reflected in the difference in folk customs, will form various communication modes and take different measures to deal with breaching contracts while transferring. Third, farmers’ behavior cognition reflects in their comprehension of the capability of executing contracts, including bargaining power, decision-making level and managing modes of the rent. The ability of behavior cognition and control of farmers has a positive influence on their behavior intention and happened.ConclusionsAccording to the above results, in order to promote the reposeful transfer and orderly development of agricultural land, the following suggestions are proposed: The first is to improve the agricultural land transfer policy system, establish and improve the institutional environment for agricultural land transfer, create conditions for the establishment of farmers’ behavioral psychological contracts in the process of agricultural land transfers, and guide farmers to establish relationship psychological contracts. The second is to improve the market system, properly cultivate and develop agricultural land transfer intermediaries, reduce transaction costs, and reduce the probability of farmers’ psychological contracts being broken. The third is to guide farmers to establish a positive agricultural land transfer psychology based on their resource endowments such as labor force quality and cultural quality, and encourage farmers to make agricultural land transfer decisions such as subcontracting, leasing, reselling, and interchanging.Figure 1.Psychological contracts of agricultural land transfer forming

Study on the Influence of Accelerated Aging on the Properties of an RTV Anti-Pollution Flashover Coating.

The purpose of this work is to study the accelerated aging behavior of a room-temperature vulcanized (RTV) silicone rubber anti-pollution flashover coating. Red, blue and gray RTV rubber samples were selected to prepare coatings on the surface of stainless-steel sheets. The accelerated aging test was carried out in an aging test chamber according to a four-step program cycle. After the completion of different aging tests, the color difference, glossiness, surface micromorphology, wettability, insulation performance and other parameters of the samples were measured using colorimetry, infrared spectrometry, scanning electron microscopy, and a high-voltage breakdown tester. The results showed that with the increase in aging time, the color difference ∆Eab of the coatings increased. The G60 gloss value decreased gradually and tended to be saturated after 60 cycles. After the aging tests, the RTV coating surface had holes, cracks, peeling and other damage to varying degrees. The C:Si atomic ratio was less than 2, and the hydrophobicity was obviously deteriorated. After aging, the electrical strength of the three RTV coatings decreased significantly. It can be concluded that during the accelerated aging test, the RTV coating had cross-linking and oxidation reactions, and the internal deterioration and surface damage of the coating led to changes in its color, luster, morphology, insulation strength, etc.

Vacuum swing adsorption for R-32 recovery from R-410A refrigerant blend

The recovery of high purity fluorinated gases from refrigerant blends is vital to promote a circular economy in the field of refrigeration and air conditioning. In this work, we evaluate the performance of a four-step Vacuum Swing Adsorption (VSA) process using activated carbon for the recovery of R-32 (difluoromethane) from a R-410A refrigerant blend: a binary mixture of R-125 (pentafluoroethane) and R-32 (yR−32=0.7; yR−125=0.3). Breakthrough curves were performed using dilute and bulk feed concentrations to determine mass and heat transfer parameters, which were then employed in simulations of fixed-bed adsorber dynamics. The mathematical model employed successfully predicts the experimental results of a four-step VSA cycle (feed, blowdown, purge, pressurization). The VSA performance was evaluated using process simulation. For a cycle time of 800 s (each step taking 200 s) and feed and regeneration pressures of 1.01 and 0.01 bar, respectively, R-32 is obtained with 97.0 mol-% purity and 30.9% recovery, with process productivity of 4.06 mol h−1 per kilogram of adsorbent, and energy consumption of 123.2 kJ/mol. Our results demonstrate the feasibility of using VSA processes for the recovery of R-32 from the near-azeotropic R-410A refrigerant blend.

Processive binding mechanism of Cel9G from Clostridium cellulovorans: molecular dynamics and free energy landscape investigations.

The degradation of recalcitrant polysaccharides such as cellulose and chitin requires the synergistic functionality of processive glycosidase (GH) cocktails. Understanding the fundamental phenomenon of processivity is of biological and economic importance for the conversion of biomass into biofuel. In this work, cellulase family 9 from Clostridium cellulovorans (Cel9G), which is a processive endoglucanase, was used to elucidate the processive binding mechanism with respect to polysaccharides, since it exhibits a multimodular crystallographic structure. Metadynamics and molecular dynamics simulations were performed to explore the dynamics of cellulose chain binding to Cel9G via processive motion. The processive movement of the cellulose chain towards the catalytic domain may exhibit several local minima, which are related to strong CH/π interactions between the sugar rings and the aromatic residues distributed at the active site. For the binding of the G6 and G12 molecules, the energy barriers were determined to be 4.8 and 7.4 kcal mol-1, respectively. Based on the site-directed mutagenesis simulations of Y520A, it was found that the existence of Y520 is critical for processive binding. It is likely that Y520 and H125/Y416 form two anchor points to facilitate processive binding to polysaccharides. More importantly, the straight-line morphology of the substrate could be observed after the formation of the so-called slide mode, which is different from the V-shaped Michaelis complex structure revealed by quantum mechanics/molecular mechanics simulations. This indicates that an additional step, namely, catalytic activation, probably exists between processive binding and the hydrolysis reaction. Finally, a four-step catalytic cycle was proposed for Cel9G. Our work provides novel molecular-level insights into the structure-function relationship for the processive enzyme Cel9G and should aid the development of improved GH cocktails for the efficient cleavage of glycosidic linkages.

A novel clean hydrogen production system combining cascading solar spectral radiation and copper-chlorine cycle: Modeling and analysis

In this work, a novel integrated hydrogen production system was proposed. A detailed analysis of the efficiency limit, energy requirement, and parametric impact was theoretically performed. The system combined cascading solar spectral radiation with a copper-chlorine thermochemical cycle, which effectively converted different grades of solar energy to clean hydrogen. The process of a four-step copper-chlorine cycle was simulated to obtain the energy demands using Aspen Plus software. A model for cascading utilization of solar spectral radiation was developed to select the optimal segmented wavelengths and investigate the effects of parameters on the system efficiency. The system designs integrated with other solar cells were also optimized using this model. Among the parameters, the segmented wavelengths were the key parameters that determined the amount of solar energy converted to heat and electricity. The theoretical calculations and simulations were used to determine the performance of this new hydrogen production system. Efficiency analysis demonstrated that the proposed system achieved an ideal efficiency of 68.20%, exceeding the theoretical limit of the single-junction photovoltaic-electrolysis water system. The efficiency of the actual design was 43.44%, higher than the systems without a spectrum splitting module. This study provides an efficient method for realizing high efficiency and high-grade solar energy cascading utilization for producing clean hydrogen energy.

Methane liquefaction with an active magnetic regenerative refrigerator

This manuscript reports liquefaction of methane using an active magnetic regenerative refrigerator (AMRR) which cooled from 285 K to 135 K. This refrigerator has two identical regenerators fabricated with adjacent layers of four ferromagnetic refrigerants, each with sequentially lower Curie temperatures and lesser masses from hot to cold temperatures. The refrigerants either heated or cooled by the magnetocaloric effect when moved in or out of a high-field superconducting magnet. The dual multilayer regenerators were assembled in opposition with a common cold region between them. The same mass of helium heat transfer gas was circulated through all layers of the regenerators during the two flow steps of the four-step AMR cycle. A compact coil-fin tube heat exchanger closely fitted around a small liquid storage vessel mounted in the cold region of the assembly was alternatively cooled by cold 2.76 MPa helium gas during hot-to-cold flow steps of the AMRR cycle. In this experiment the cold coil-fin tube heat exchanger was used to cool and liquefy a process stream of methane gas supplied at 295 K from a lecture bottle at different pressures in different runs. By measuring time to liquefy a known volume of methane at three different pressures, cooling powers of the AMRR as a function of temperature were determined. The resultant data were compared to values predicted by the cooling power equation of the AMRR model. Conclusions from these experiments and suggestions for future work are presented.

The very long-chain fatty acid elongase FgElo2 governs tebuconazole sensitivity and virulence in Fusarium graminearum.

Very long-chain fatty acids (VLCFAs), the precursors for the synthesis of sphingolipids (SLs), play pivotal roles in the development and stress response in eukaryotes. In Saccharomyces cerevisiae, VLCFAs are synthesized in the endoplasmic reticulum (ER) through a four-step elongation cycle. However, the functions of VLCFA elongases in phytopathogenic fungi remain largely unexplored. Here, we identified a single copy of the VLCFA elongase gene FgELO2 in Fusarium graminearum that causes Fusarium head blight worldwide. FgElo2 localized to ER membrane, and deletion mutant of FgELO2 exhibited serious defects in vegetative growth and conidiation. Importantly, ΔFgElo2 led to ergosterol content reduction and disrupted the ER-localization of 14-α-demethylase FgCyp51s, indicating that the scarce of SLs reduced ergosterol, which ultimately elevated the sensitivity of ΔFgElo2 to tebuconazole. Fluorescent microscopic examination suggested that FgElo2 was degraded upon cell membrane stress. ΔFgElo2 showed decreased phosphorylation of high osmolarity glycerol (HOG) pathway and subsequently exhibited remarkable sensitivity to osmotic stress. In addition, fungal virulence was dramatically reduced in ΔFgElo2 via inhibiting deoxynivalenol production and formation of infection structures. Together, this study demonstrates that the VLCFA elongase FgElo2 modulates fungal development, tebuconazole sensitivity, stress responses and virulence, which may advance our understanding of pathogen-host interactions mediated by VLCFAs.