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Construction of robust and efficient yeast strains is a prerequisite for commercializing a biofuel production process. We have demonstrated that high intracellular spermidine (SPD) contents in Saccharomyces cerevisiae can lead to improved tolerance against various fermentation inhibitors, including furan derivatives and acetic acid. In this study, we examined the potential applicability of the S. cerevisiae strains with high SPD contents under two cases of ethanol fermentation: glucose fermentation in repeated-batch fermentations and xylose fermentation in the presence of fermentation inhibitors. During the sixteen times of repeated-batch fermentations using glucose as a sole carbon source, the S. cerevisiae strains with high SPD contents maintained higher cell viability and ethanol productivities than a control strain with lower SPD contents. Specifically, at the sixteenth fermentation, the ethanol productivity of a S. cerevisiae strain with twofold higher SPD content was 31% higher than that of the control strain. When the SPD content was elevated in an engineered S. cerevisiae capable of fermenting xylose, the resulting S. cerevisiae strain exhibited much 40-50% higher ethanol productivities than the control strain during the fermentations of synthetic hydrolysate containing high concentrations of fermentation inhibitors. These results suggest that the strain engineering strategy to increase SPD content is broadly applicable for engineering yeast strains for robust and efficient production of ethanol.

This paper presents a newly designed fault-ride-through (FRT) scheme i.e. bridge-type fault-current limiter (BFCL) for Grid-Tied photovoltaic system (PVS) to optimize unbalance fault variables. A 100 kW three-phase Grid-Tied MATLAB/Simulink model is used to analyze the system response during unbalance conditions. The simulation results of designed FRT scheme are critically compared with conventionally adopted FRT scheme i.e. crowbar circuitry. However, for inverter control proportional integrator (PI) controller is used. Moreover, the analysis is carried out for faults at point of common-coupling (PCC) as well as 5-km away from PCC. The obtained simulated results of PI controller with well-designed FRT scheme authenticates stable, minimum oscillation, ripples free, robust and fast performance for unbalance fault variables as compared to previous work.

International audience ; We investigate a spectrum sharing system that enables energy harvesting from distributed multi-antenna energy transmitter devices for primary dual-band device-to-device networks and secondary dual-band wireless sensor networks (WSNs), incorporating a multi-stage rectenna energy harvesting circuit model. We formulate a new multi-hop routing problem for network energy efficiency maximization of this system, which involves the interconnected tasks of WSN routing, controlling the transmit power of sensor nodes, and energy transmitter clustering, taking into account interference, power budget and rate constraints. To tackle these interconnected tasks effectively, we propose an integrated solution that includes both centralized and distributed routing schemes. Furthermore, the solution incorporates energy transmitter clustering schemes based on harvested power and channel gain. We provide an analysis of the computation complexity and signaling overhead for the proposed solution. Our simulation results demonstrate that the proposed routing and clustering schemes outperform their respective benchmark schemes, achieving significant performance gains.

The requisition for maintainable constructions has been greatly raising over the last several years. To fulfil the maintainability necessities of a construction, decisions or changes must be done to a construction in the course of the preconstruction and design steps. This can be plausible utilizing building information modelling. To indicate the utilize of building information modelling in maintainable planning, an example nursing-house is received for modelling research. The energy efficiency of nursing-home is analysed utilizing Autodesk Revit and Green Building Studio simulation which contained different characteristics such as annual heating and cooling loads, annual energy usage. Through using the utilize of different building, insulation and roof materials in the nursing-home modelling, the nursing-home modelling is changed into a greener construction modelling. In addition, the effects of using green walls on the facade of the building on the energy performance were analysed. Utilizing simulation, the utilize of non-natural sources can be dramatically decreased through substituting for them with the utilize of sustainable natural sources by that means energy saving. Building information modelling has substantiated to be effective in providing maintainability with alternative material’s assessment and earlier decision-making. Furthermore, this study employed an integrated new MCDM model to evaluate the performance of four natural stones for utilize in a nursing home setting.

The characteristics of spray behavior and combustion of DME (dimethyl ether) were investigated using experimental and numerical approaches. For experiments, injection rates and macroscopic spray characteristics were investigated at various injection parameters by using an injection rate system and a spray visualization system. The combustion and emission characteristics were also obtained from the modified engine for DME fuel and emission measurement equipment. For numerical approaches, the combustion characteristics of DME fueled engine were predicted by a 3D-CFD code, the KIVA code coupled with the CHEMKIN (KIVA-CHEMKN) and spray behavior and evaporation were calculated by considering the thermo-chemical properties of DME. In order to calculate the fuel oxidation and emission formation such as NOx, a detailed chemical kinetic mechanism which was composed of 83 species and 360 reaction paths was considered. To simulate soot emission, two-step phenomenological model was applied. Both experimental and numerical results indicate that injection delay, ignition delay, and combustion duration of DME are shorter than that of diesel because of good evaporation and mixing characteristics. The pressure history predicted by the KIVA code agrees well with the measurements from the test engine. The amount of NOx emission was predicted by the reduced NOx mechanism shows good agreements to the experiments.

This study explores heat transfer behaviour in mixed convection of a fluid with internal heat generation, a situation found in chemical and nuclear engineering contexts. Computational fluid dynamics is used to simulate laminar ascending mixed convection flow of a heat-generating fluid in a vertical cylinder with uniformly cooled wall, based on a liquid nuclear fuel concept. A new non-dimensional parameter, the IHG-flux number Ω, is developed to express the balance of axial convection versus radial conduction heat transfer. It was found that heat transfer behaviour depends on this parameter, and it can be used as the transition criterion to categorise the simulated results into three distinct heat transfer regimes. A heat transfer correlation using Ω was also developed for Regime I with small values of Ω, where convection and conduction effects are balanced in a stable flow. In Regime II at intermediate Ω, stronger convection gives rise to flow instability. In Regime III with large Ω, convection dominates and the temperature profile inverts so that the maximum temperature occurs at the wall, while instability remains likely.

Abstract Rice husk (RH), an agricultural waste, is abundantly available in rice producing countries like China, India, Bangladesh, Brazil, US, Cambodia, Vietnam, Myanmar, and South East Asia. Despite the massive amount of annual production worldwide, so far RHs have been recycled only for low-value applications. In recent years, many rice mills in rice producing countries have started using RH for the energy production for mill operations as well as household lighting in rural regions. Burning of RHs produces the rice husk ash (RHA). The disposal in landfills or open fields can be problematic and may cause a serious environmental and human health related problems due to the low bulk density of RHA. Several ways are being thought of for disposing RHA by making its commercial use. The amorphous silica forms the main component (83–90%) of RHA. The amorphous silica rich RHA has wide range of applications. High-value applications and current research investigations such as the use of RHA in manufacturing of silica gels, silicon chip, synthesis of activated carbon and silica, production of light weight construction materials and insulation, catalysts, zeolites, ingredients for lithium ion batteries, graphene, energy storage/capacitor, carbon capture, and in drug delivery vehicles are presented. Use of RHA in potential future applications is also discussed. It is suggested that the amorphous silica rich RHA could become a potential resource of low cost precursor for the production of value-added silica based materials for practical applications.

A data-driven approach is developed to predict the future capacity of lithium-ion batteries (LIBs) in this work. The empirical mode decomposition (EMD), kernel recursive least square tracker (KRLST), and long short-term memory (LSTM) are used to derive the proposed approach. First, the LIB capacity data is split into local regeneration and monotonic global degradation using the EMD approach. Next, the KRLST is used to track the decomposed intrinsic mode functions, and the residual signal is predicted using the LSTM sub-model. Finally, all the predicted intrinsic mode functions and the residual are ensembled to get the future capacity. The experimental and comparative analysis validates the high accuracy (RMSE of 0.00103) of the proposed ensemble approach compared to Gaussian process regression and LSTM fused model. Furthermore, two times lesser error than other fused models makes this approach an efficient tool for battery health prognostics.