Finite Set Model Predictive Current Control of a Grid Converter Equipped with an LCL Filter

A grid converter is a critical component used to synchronize a renewable energy source with the utility grid and are also used as an active front-end rectifier for motor drives. Converter switching actions produce harmonics and therefore, it is equipped with an LCL filter to feed smooth sinusoidal current to the grid. However, the resonance behaviour of LCL filter amplifies the harmonics appearing at its resonant frequencies, therefore resonance damping is necessary. This thesis proposes a current controller based upon finite set model predictive control for current tracking and active damping of the LCL filter resonance. The current prediction for the controller is done in a small horizon window and the possibility to extend it to longer horizon has been explored. A hold equivalent discrete-time model with zero-order-hold assumption is used by the controller for predicting current for future time instants using the present state measurement. The current controller also uses an observer to enhance its disturbance rejection capability and reduce the need of additional sensors required to run the controller. The dynamic performance and robustness of the finite set model predictive current controller is demonstrated through simulation results

Bioprocessing of Crop Residues using Fibrolytic Enzymes and Flavobacterium bolustinum for Enriching Animal Feed

Flavobacterium bolustinum and its extracellular cellulase were tested for animal feed pretreatment. The fibrolytic enzymes, cellulase and pectinase were applied to various crop residues such as wheat straw, rice straw, corn seeds and sorghum for enriching animal feed. Different parameters like temperature, incubation time and enzyme dose had been optimized for maximum reducing sugar and protein release. The highest amount of reducing sugar obtained was 29.83 mg g-1 dry substrate and soluble protein was 27.34 mg g-1 dry substrate on single cellulase enzyme treatment at 50°C for 6 h. An increase in amount of released reducing sugar (39.5 mg g-1 dry substrate) and protein (33.88 mg g-1 dry substrate) was observed when enzyme cocktail (cellulose and pectinase) was used. Solid state fermentation using F. bolustinum had also been performed for all crop residues. It released higher amount of reducing sugar (41.36 mg g-1) and protein (47.21 mg g-1) as compared to enzymatic treatment. Different substrates resulted in appreciable weight loss by enzymatic treatment (15-35%) as well as fermentation using F. bolustinum (40%). Liquefaction of lignocellulosic rich crop residues, for better utilization of feed has never been reported earlier

Intraarticular versus intravenous tranexemic acid in reducing blood loss after primary total knee arthroplasty

Background: One of the substantial complications of total knee arthroplasty is major blood loss. Postoperative blood loss can range up to 2000 ml and 10-38% of patients may require blood transfusion. Among the sundry methods of preventing this prob, tranexamic acid, an anti-fibrinolytic, is one of the most effective options. It can be administered directly into the blood or injected locally. The purpose of this study was to compare the hemostatic effects of intraarticular versus intravenous administration of tranexamic acid in primary total knee arthroplasty. Methods: A prospective comparative observational study was done from done September 2020 to February 2022 at Civil Service Hospital, Kathmandu. 64 patients randomized into two groups: an intraarticular tranexamic acid group (31 patients who received 3.0 grams of intraarticular tranexamic acid) and intravenous tranexamic acid group (31 patients who received 15 mg/kg intravenous tranexamic acid in two instances). The primary measure was the amount of hemoglobin loss. Secondary outcomes included comparison of hemoglobin level pre- and post- operatively at first and fifth day, drain volume at 48 hours and amount of blood transfusion. There were no significant differences in demographics or preoperative laboratory values between the groups. Results: The baseline data, preoperative hemoglobin, and tourniquet time were similar in both groups. Hemoglobin at first and fifth operative day and drain volume at 48 hours were measured in both categories. There was no significant difference in perioperative blood loss, drain volume, rates of allogeneic blood transfusion between the two groups.  No any thromboembolic complications occurred. Conclusions: Intra-articular administration of tranexamic acid was found to be as effective and safe as intra-venous administration in reducing blood loss in primary total knee arthroplasty

Affinity flow fractionation of cells via transient interactions with asymmetric molecular patterns

Flow fractionation of cells using physical fields to achieve lateral displacement finds wide applications, but its extension to surface molecule-specific separation requires labeling. Here we demonstrate affinity flow fractionation (AFF) where weak, short-range interactions with asymmetric molecular patterns laterally displace cells in a continuous, label-free process. We show that AFF can directly draw neutrophils out of a continuously flowing stream of blood with an unprecedented 400,000-fold depletion of red blood cells, with the sorted cells being highly viable, unactivated, and functionally intact. The lack of background erythrocytes enabled the use of AFF for direct enumeration of neutrophils by a downstream detector, which could distinguish the activation state of neutrophils in blood. The compatibility of AFF with capillary microfluidics and its ability to directly separate cells with high purity and minimal sample preparation will facilitate the design of simple and portable devices for point-of-care diagnostics and quick, cost-effective laboratory analysis

Weed dynamics, wheat (Triticum aestivum) yield and irrigation water-use efficiency under conservation agriculture

A field experiment was conducted to evaluate the impacts of a 12-year old conservation agriculture (CA)- based pigeon pea-wheat system on weeds, wheat crop, and resource use during winter (rabi) 2021–22. Results indicated that surface retention of residue irrespective of ZT permanent bed and N dose led to significant reduction in weed interference at 60 DAS. CA-based systems reduced weed density and dry weight considerably than CT. CA- based systems led to significantly higher wheat grain yield (by 11.6–14.9%) and net B:C (by 24.0 –28.0%) than CT, and PFBR100N and PBBR100N were slightly superior to others. PBBR100N and PBBR75N had lower irrigation water use and significantly higher irrigation water productivity than CT. Contrast analysis showed that wheat yield and water productivity were comparable between 75% N and 100% N in CA, indicating a saving of 25% N under CA

Sequential herbicide application coupled with mulch enhances the productivity and quality of winter onion (Allium cepa L.) while effectively controlling the mixed weed flora

Weed control poses substantial difficulties for winter season onion (Allium cepa L.) cultivation in the north-western Indo-Gangetic Plains, primarily due to the constrained efficacy of the existing herbicides. To address this issue, a 2-year field study was conducted to assess the efficacy of pre- and post-emergence herbicides (pendimethalin, ethoxysulfuron, imazethapyr, and quizalofop-p-ethyl) individually and in combination with crop residue mulch for weed control in winter onion. The results revealed that using herbicides or mulches in isolation did not provide satisfactory weed control. However, the integration of natural mulch with pendimethalin followed by quizalofop-p-ethyl application proved to be the most effective weed control strategy, resulting in the least reduction in bulb yield (10.3%) compared to other treatments. On the contrary, combinations of pendimethalin with ethoxysulfuron or imazethapyr showed adverse effects on the onion crop and inflicted the highest yield losses among all treatments (78.6 and 83.4%, respectively). However, the combination of pendimethalin with quizalofop-p-ethyl coupled with crop mulch resulted in season-long weed control and over 80% bulb yield (36.58 t/ha) gains compared to the weed-free condition. These findings emphasize the efficacy of combining herbicides and mulches as an integrated weed management strategy for onions. By adopting such integrated approaches, farmers could improve weed control while maintaining bulb yield and quality, reducing the risks associated with herbicide resistance, and promoting sustainable onion production in the north-western Indo-Gangetic Plains

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis