Real and Reactive Power Control of Induction Motor Drives

Induction motors are considered the workhorse in the majority of industrial applications. Their rugged, low-maintenance, and efficient designs keep finding new forms of use nowadays. In this work, power control strategies of induction motor drives based on principles of Direct Torque Control and Model Predictive Control are investigated. The proposed methods control the real and reactive power flow into/out of the machine by selecting and applying proper voltage space phasors to the stator. First, the impact of voltage space phasors on real and reactive power variations is explored. Based on these observations, two methods to choose the appropriate voltage space phasors are proposed based on: six-sector and twelve-sector direct power control, and model predictive power control. Methods to calculate reference and motor powers are then introduced. The presence of high currents during the motor start-up period is analyzed and solutions to limit them are proposed. Finally, simulations using ®Matlab ™Simulink are carried out to test the performance of the control strategies under different operating conditions, including presence of motor parameter variations

Can Maquila Booms Reduce Poverty? Evidence from Honduras

This paper identifies and estimates the strength of the reduction in poverty linked to improved opportunities for women in the expanding maquila sector. A simulation exercise shows that, at a given point in time, poverty in Honduras would have been 1.5 percentage points higher had the maquila sector not existed. Of this increase in poverty, 0.35 percentage points is attributable to the wage premium paid to maquila workers, 0.1 percentage points to the wage premium received by women in the maquila sector, and 1 percentage point to employment creation. Given that female maquila workers represent only 1.1 percent of the active population in Honduras, this contribution to poverty reduction is significant.Trade liberalization; maquila; poverty; gender wage gap; Honduras

Flow cytometric assessment of the reactivity of a panel of monoclonal antibodies (mAb) against two populations of human dendritic cells (DC)

BACKGROUND: The identification of antigens on human DC has been a very difficult and elusive task because of the lack of appropriate reagents. Therefore, we evaluated by flow cytometry a panel of mAb that recognize antigens on human DC, aiming to determine the kinetics of DC antigen expression at 7, 14, 21 and 28 days in (i) Dermal DC like cells (Mo-DC) and (ii) Langerhans cell like DC (Mo-LC). In addition we aimed to identify markers for DC subpopulations. RESULTS: It was found at day 7, that mAb BG6, HP-F1, BU10, RFD-1, CMRF-44 recognized <20% of Mo-DC. In contrast, 7H5, ZM3.8, CDlb/c, 55K-2, MMR1.16, MMR190.BB3 and L25 reacted with >50% of Mo-DC. Moreover, 7H5, ZM3.8, CMRF-56, CDlb/c, 55K-2, MMR1.16, MMR190.BB3 and L25 showed increased MFI reactivity against Mo-DC. mAb BG6, BU10 and CMRF-44 recognized <20% Mo-LC while RFD-1 reacted with 21% of Mo-LC. In contrast, HP-F1 showed 87% of Mo-LC positive. Also, 7H5, ZM3.8, RFD-7, MR15-2, CDlb/c, 55K-2, MMR1.16, MMR190.BB3 and L25 reacted with >50% of Mo-LC. The increase in % of positive cells was paralleled by MFI increases. At day 14, fourteen mAb recognized >50% of the Mo-DC, while five recognized 20-50% of Mo-DC. BG6 reacted with 7% of the Mo-DC. Nineteen mAb recognized >48% of Mo-LC while BG6 had negative reactivity. At day 21 and 28, all mAb reacted with >20% of Mo-DC and yielded a significant MFI with Mo-DC. Also nineteen mAb yielded significant MFI with Mo-LC while RFD-7 did not. CONCLUSIONS: The immunophenotyping assays demonstrated differences between the two DC populations as well as variations in the reactivity of the mAb at diverse time points, suggesting the existence of subpopulations within the Mo-DC and Mo-LC

Flow cytometry analysis of the effect of allopurinol and the dinitroaniline compound (Chloralin) on the viability and proliferation of Leishmania infantum promastigotes

BACKGROUND: Leishmaniasis is a major parasitic disease in the tropical regions. However, Leishmania infantum has recently emerged as a very important cause of opportunistic infections for individuals positive for human immunodeficiency virus (HIV). However, there is a lack of in vitro tests for assessing the effect of anti-parasitic drugs on the viability and proliferation of Leishmania infantum. The aim of this study is to assess the efficacy of anti-parasitic drugs like allopurinol and Chloralin on the viability and proliferation of L. infantum promastigotes by utilizing two complementary flow cytometric approaches after exposure of the promastigotes to various concentrations of the drugs. RESULTS: The density of the cultures in the presence and absence of allopurinol was determined by haemocytometer enumeration. The two flow cytometric approaches used to monitor the drug effect were: (i) a quantitative method to measure cell division using 5-,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) staining and (ii) evaluation of cell viability by dual-staining with the membrane-permeable nuclear stain, SBRY-14 and propidium iodide. It was found that concentrations of allopurinol above 50 μg/ml yielded a clear decrease in the proliferation rate of the promastigotes. However, the viability results showed that about 46.8% of the promastigotes incubated in the presence of 800 μg/ml of allopurinol were still alive after 96 hours. In sharp contrast, more than 90% of promastigotes treated with Chloralin 10 μM (2.7 μg/ml) were dead after 48 hours of treatment. These flow cytometric findings suggest that allopurinol has a leishmaniostatic effect while the dinitroaniline compound (Chloralin) has a leishmaniocidal effect against promastigotes. CONCLUSIONS: The flow cytometric data on proliferation and viability were consistent with results obtained from haemocytometer counts and allowed us to develop a model for assessing in vitro the effects of medicaments like allopurinol and chloralin on L. infantum promastigotes on a cellular level

High-Performance Simultaneous Multiprocessing for Heterogeneous System-on-Chip

This paper presents a methodology for simultaneous heterogeneous computing, named ENEAC, where a quad core ARM Cortex-A53 CPU works in tandem with a preprogrammed on-board FPGA accelerator. A heterogeneous scheduler distributes the tasks optimally among all the resources and all compute units run asynchronously, which allows for improved performance for irregular workloads. ENEAC achieves up to 17\% performance improvement \ignore{and 14\% energy usage reduction,} when using all platform resources compared to just using the FPGA accelerators and up to 865\% performance increase \ignore{and up to 89\% energy usage decrease} when using just the CPU. The workflow uses existing commercial tools and C/C++ as a single programming language for both accelerator design and CPU programming for improved productivity and ease of verification.Comment: 7 pages, 5 figures, 1 table Presented at the 13th International Workshop on Programmability and Architectures for Heterogeneous Multicores, 2020 (arXiv:2005.07619

Effects of Managing Heifers to Calve First at Two \u3ci\u3evs\u3c/i\u3e Three Years of Age on Longevity and Lifetime Production of Beef Cows

Resources used by cow herds for beef production vary greatly. To optimize reproduction and other production characteristics in the cow herd, breeding and management should be matched with the feed resources available for production. One management decision is whether to develop replacement females to calve first as 2-year-olds or as 3-year-olds. When feed resources are limited or expensive relative to other costs and value of output, it may be economical to delay the first calving until 3 years of age. When feed resources are adequate to support rapid growth and development of heifers and thus to reduce age at puberty to 14 months of age or less, then calving at 2 years of age may be optimum. another management decision is whether or not cows should be culled the first time they are open, or held over for another opportunity to breed (in lieu of keeping an additional replacement heifer). This study was conducted to evaluate effects of 2-year-old vs 3-year-old first calf management on longevity and lifetime production of cows and on current economics of beef production

Effects of Heterosis on Longevity in Beef Cattle

Longevity can be important to the economic efficiency of beef production. The longer cows remain productive in a herd, the fewer the number of replacement heifers needed and the greater the calf output per cow maintained. In this way, more heifers can be sold for feeding and slaughter, and the cost of growing out replacement females to a productive age is reduced. Less culling of infertile cows also increases output per cow exposed. This study was conducted to determine effects of heterosis on longevity and associated factors in crosses of the Hereford, Angus, and Shorthorn breeds