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This paper presents the direct power control (DPC) of asymmetrical six-phase permanent magnet synchronous generator (A6PMSG) which supplied the isolated load via two PWM rectifiers. The study concerns the method of control by the converter (DPC). The proposed method is around two hysteresis controllers that enable the adjustment of active and reactive power. The research in this paper is verified by MATLAB SIMULINK software. It has been demonstrated through the simulation results that the proposed strategy can be an attractive and practical solution to multi-phase machines applications.

Abstract Bed expansion of fine powders was investigated in two high aspect ratio fluid beds, an expanded top bed and a circulating system. The range of gas velocities (0.07 – 8 m/s) spanned the bubbling/slugging, turbulent, fast, and dense conveying fluidization regimes. The two-phase theory was shown generally not to apply in the slugging and the higher velocity fluidization regimes. A modified Richardson-Zaki approach, using an ‘effective’ cluster terminal velocity, was shown to adequately describe bed expansion. Changes in slope of the expansion curve were associated with regime changes, and can prove useful for the analysis of large diameter fluid beds. The effect of particle size distribution was shown to be considerable.

Abstract A general methodology for the decomposed optimization of highly coupled, highly dynamic energy systems is presented. The approach is based on the physical division of the system into units (sub-systems, components or disciplines) subject to functions describing the energy, cost and other couplings between them. Two versions of the approach are proposed. The first approach is called the Local-Global Optimization (LGO) Approach. LGO requires unit optimizations to be carried out with respect to purely local decision variables for various combinations of the functions that connect the units. The results are used to create an Optimum Response Surface (ORS) for the entire problem. The ORS is then searched by a system-level optimizer to find the values of the coupling functions that lead to an optimum system-level solution. The second approach proposed is an iterative version of LGO (ILGO). In this case, the ORS is closely approximated using a linear Taylor series expansion. The partial derivatives resulting from such an approximation are seen to correspond to the marginal costs typically used in the thermoeconomic literature. ILGO effectively and significantly reduces the number of unit optimizations required. The properties used to describe the coupling functions play a critical role in the convergence of ILGO to a global system-level optimum. A discussion of this and its implication for the choice of First or Second-Law based quantities for the optimization of systems is given.

A promising route to transition wastewater treatment facilities (WWTFs) from energy-consuming to net energy-positive is to retrofit existing facilities with process modifications, residual biosolid upcycling, and effluent thermal energy recovery. This study assesses the economics and life cycle environmental impacts of three proposed retrofits of WWTFs that consider thermochemical conversion technologies, namely, hydrothermal liquefaction, slow pyrolysis, and fast pyrolysis, along with advanced bioreactors. The results are in turn compared to the reference design, showing the retrofitting design with hydrothermal liquefaction, and an up-flow anaerobic sludge blanket has the highest net present value (NPV) of $177.36MM over a 20-year plant lifetime despite 15% higher annual production costs than the reference design. According to the ReCiPe method, chlorination is identified as the major contributor for most impact categories in all cases. There are several uncertainties embedded in the techno-economic analysis and life cycle assessment, including the discount rate, capital investment, sewer rate, and prices of main products; among which, the price of biochar presents the widest variation from $50 to $1900/t. Sensitivity analyses reveal that the variation of discount rates causes the most significant changes in NPVs. The impact of the biochar price is more pronounced in the slow pyrolysis-based pathway compared to the fast pyrolysis since biochar is the main product of slow pyrolysis.

Many vulnerable people lose their health or lives each year as a result of unhealthy environmental conditions that perpetuate medical conditions within the scope of allergy and immunology specialists' expertise. While detrimental environmental factors impact all humans globally, the effect is disproportionately more profound in impoverished neighborhoods. Environmental injustice is the inequitable exposure of disadvantaged populations to environmental hazards. Professional medical organizations such as the American Academy of Allergy, Asthma & Immunology (AAAAI) are well positioned to engage and encourage community outreach volunteer programs to combat environmental justice. Here we discuss how environmental injustices and climate change impacts allergic diseases among vulnerable populations. We discuss pathways allergists/immunologists can use to contribute to addressing environmental determinants by providing volunteer clinical service, education, and advocacy. Furthermore, allergists/immunologists can play a role in building trust within these communities, partnering with other patient advocacy nonprofit stakeholders, and engaging with local, state, national, and international nongovernmental organizations, faith-based organizations, and governments. The AAAAI's Volunteerism Addressing Environmental Disparities in Allergy (VAEDIA) is the presidential task force aiming to promote volunteer initiatives by creating platforms for discussion and collaboration and by funding community-based projects to address environmental injustice.

Abstract The steady-state performance of the gravity-assisted, two-phase, closed thermosyphon was modeled from first principles. Liquid-film momentum advection and axial normal stress, typically neglected by previous investigators, were included and shown to be important to the thermosyphon performance. The model presented also expanded previous analyses to include both temperature and heat-flux controlled thermosyphons and thermosyphons with mixed or other external boundary conditions. Numerical techniques were incorporated to solve the nonlinear governing equations and respective boundary conditions. A series of thermosyphon experiments were conducted. Predictions from the model agree well with experimental results. The parametric effects of operating temperatures, geometry, working fluid inventory and condenser thermal capacity were studied. The model presented could be used for optimization studies and design of thermosyphons.

Abstract Bamboo has been considered a potential feedstock of energy for the future. It can be subjected to the pyrolysis for biofuels production. The thermogravimetric analysis (TGA) combined with differential thermogravimetric analysis (DTG) for bamboo was carried out prior to pyrolysis. The thermal degradation of bamboo was mainly between 230 and 420 °C. The conventional pyrolysis of bamboo was investigated in a bubbling fluidized-bed reactor using silica sand. The product distribution and composition of pyrolysis bio-oil were dependent on biomass component and operating conditions such as pyrolysis temperature, fluidization velocity, and particle size of biomass. The fractional catalytic pyrolysis of bamboo was also studied to upgrade the pyrolysis vapor, using HZSM-5 and red mud. The highest yield of bio-oil was 54.03 wt% compared to 49.14 wt% and 50.34 wt% of HZSM-5 and red mud catalyst, respectively. In the red mud catalytic pyrolysis, the oxygen content was rejected from pyrolysis vapor mostly via decarboxylation to produce more CO2 than CO; in contrast, for the HZSM-5 catalytic pyrolysis, the production of CO through decarbonylation was more favored than CO2. The main composition of catalytic pyrolysis bio-oil was 4-vinylphenol, which was employed as a raw material source to synthesize valuable material for energy storage.

Abstract The hybrid pneumatic power system (HPPS) proposed in this research replaces the battery’s electric-chemical energy with flow work and optimizes the management and utilization of the energy. This power system is able to keep the internal-combustion engine working at its optimal condition and turn its waste energy into effective mechanical energy and so enhance the thermal efficiency of the whole system. Using computer simulation software ITI-SIM, this study simulates the overall dynamic characteristics of the system in accordance with the regulated running-vehicle test-mode ECE47, and, with experimental verification and analysis, proves that this system can meet the requirements of the standard running-car mode. As for recycling the waste energy, the experimental results show that this design could offset the shortcomings of the low-density of pneumatic power and so effectively enhance the efficiency of the whole system.