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In wind energy conversion system, extraction of optimum power and efficient operation are two major challenges. In grid connected mode, a doubly fed induction generator (DFIG) control unit is designed to operate at optimum speed to deliver maximum output power in the grid while the voltage, frequency and harmonic regulations need to be fulfilled. Vector control associated with proportional-integral (PI) controllers has been widely applied in wind farms for reliable power regulation of DFIG. As DFIG based wind energy conversion system (WECS) experiences strong nonlinearity and uncertainties originated from the aerodynamics of the wind turbine and magnetic saturation of the generator, different adaptive and nonlinear control schemes have been proposed to resolve the problems associated with fixed-gain PI controllers.

NanoLuc (NLuc) luciferase has found extensive application in designing a range of biological assays including gene expression analysis, protein-protein interaction and protein conformational changes due to its enhanced brightness and small size. However, questions related to its mechanism of interaction with the substrate, furimazine, as well as bioluminescence activity remains elusive. Here, we combined molecular dynamics (MD) simulation and mutational analysis to show that the R162A mutation results in a decreased but stable bioluminescence activity of NLuc in vitro. Specifically, we performed multiple, all-atom, explicit solvent MD simulations of the apo and furimazine-docked (holo) NLuc structures revealing differential dynamics of the protein in the absence and presence of the ligand. Further, analysis of trajectories for hydrogen bonds (H-bonds) formed between NLuc and furimazine revealed substantial H-bond interaction between R162 and Q32 residues. Mutation of the two residues in NLuc revealed a decreased but stable activity of the R162A, but not Q32A, mutant NLuc in in vitro assays performed with furimazine. In addition to highlighting the role of the R162 residue in NLuc activity, we believe that the mutant NLuc will find wide application in designing in vitro assays requiring extended monitoring of NLuc bioluminescence activity.

The cobalt ferrite (CoFe2O4) nanoparticles were synthesized by chemical co-precipitation technique and characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Mössbauer spectroscopy. The CoFe2O4 nanoparticles coated with biocompatible chitosan at different concentrations to produce homogeneous suspensions were also characterized by dynamic light scattering (DLS) and hyperthermia set-up. XRD data of the sample explored the particle size near about 7 nm in as-dried condition. TEM micrograph of bare CoFe2O4 nanoparticles provided the particle size nearly too about 8 nm which is in good agreement with the XRD data. This particle size after coating with chitosan became 14 nm. EDX results of this sample confirmed its nano dimension with spinel structure. VSM results of the sample in as-dried condition showed the ferromagnetic character which has been beyond proved by Mössbauer spectroscopy. The hydrodynamic diameter (Hd) and polydispersity index (PDI) of the chitosan-coated samples also provided promising results. The samples were tested for their induction heating properties with an RF magnetic field of 20 mT and a frequency of 342 kHz. We also studied therapeutic efficiency in-vitro on 9L gliosarcoma cancer cells, which revealed > 98% of mortality through hyperthermia protocol with the same RF field and frequency using chitosan-coated CoFe2O4nanoparticles. GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 7, Dec 2020 P 69-75

The study was conducted to analyze the groundwater potential zones in the Eastern part of Kushtia district. Secondary data collected from Bangladesh Agriculture Development Board Corporation (BADC) and borehole data of 119 locations have been processed, analyzed and interpreted for studying the hydrogeological properties. The sub-surface groundwater-bearing sequence of the area up to the depth of 97 m have been classified into two main hydrostratigraphic units- aquitard and aquifer, consisting of clay-silt-sand and sands of different granular respectively. The 18-30 m thick aquitard is covering a major part of the study area. The thickness of main aquifers is varying from 0.9-30 m and 27-67 m consisting of fine-medium to coarse sand. The yield potential index is 1.3-13.0. However, from the obtained results, it can be concluded that the area is suitable for groundwater potentiality. GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 7, Dec 2020 P 36-41

Intrinsic zinc oxide thin films have deficiencies in terms of structural, optical and electronic characteristics, which has given rise to researches on metal doped zinc oxide films in the interest of enhancing its characteristics. Indium tin oxide, Au, Ag, Pt and Ti; which are extensively used in industrial level thin film applications but aluminum has low cost than those metals, so by doping with this on ZnO thin films, its performance and quality on the morphological, elemental, structural, optical and electrical attributes were analyzed in this research. Tuning of ZnO nanocrystalline thin films’ optical band gap, doped by different materials simplifies possible elements for photonic applications. Sol–gel spin coating method has been used for these analyses which was accustomed to gain the Al doped ZnO (AZO) parent compounds on silicon-glass substrates. Ultra violet visible spectrophotometer was used to determine band gap tuning characteristics, urbach energy, transmittance and absorption properties. The Moss-Burstein outcome imprints the blue shift with thickness increment of the absorption end and there is a clear relationship between band gap and urbach energy. Tuning of band gap value varies from 3.22 eV to 3.26 eV by varying the film thickness from 100 to 300 nm. A non-linear, non-monotonic relation has been seen for the change of optical and structural parameters of AZO thin films. Deep research of structural and optical properties represents important information to get a better perspective of band gap dependence on structural properties.

The computer control plays important role in the solar cell design and development of dual axis solar tracker for the sun's position. The main goal of this paper is to maximize energy output to reduce panel temperature (cooling), to increase efficiency of the PV panel. Small-scale solar is developed through a complete hardware and software in order to function accurately. The main parts in this work are Arduino Uno R3, kit relay, LDR (Light Dependent Resistor), LM35 (temperature sensor), high-efficiency solar panel and satellite motor. The Protuse software is used with (Arduino Uno) as embedded computer control. The results show the effectiveness of the complete tracking system.

The present study has been undertaken to depict spatial distribution of different aquifer parameters in the eastern part of Kushtia district through a detailed hydrogeological survey. For this investigation, 119 lithologs and 92 pumping test data have been used. These data have been processed, analyzed, interpreted and krigged for the spatial assessment of the aquifer properties viz. transmissivity, hydraulic conductivity, hydraulic diffusivity, specific yield, radius of influence, and specific drawdown. It is seen from the investigation that the transmissivity and hydraulic conductivity values obtained from the pumping tests of the wells are varying from 1811 m2/day to 2568 m2/day and 32.5 m/day and 61.5 m/day respectively, the hydraulic diffusivity being ranging from 181,143 m2/day to 256,788 m2/day. The estimated specific yield of 17.97% - 23.46% supports that the area is dominated with coarse grained sands. This study reveals that the distribution of deep tube wells in the area are not within the radius of influence (638 - 760 m) each other, but few shallow and hand tube wells existed within the radius of influence. The estimated specific draw down is varying from 57 m/cumec to 126.1 m/cumec. From the overall analysis, it is found that the area is favorable for groundwater exploration.

Globally, real-time reverse transcription-polymerase chain reaction (rRT-PCR) is the reference detection technique for SARS-CoV-2, which is expensive, time consuming, and requires trained laboratory personnel. Thus, a cost-effective, rapid antigen test is urgently needed. This study evaluated the performance of the rapid antigen tests (RATs) for SARS-CoV-2 compared with rRT-PCR, considering different influencing factors.We enrolled a total of 214 symptomatic individuals with known COVID-19 status using rRT-PCR. We collected and tested paired nasopharyngeal (NP) and nasal swab (NS) specimens (collected from same individual) using rRT-PCR and RATs (InTec and SD Biosensor). We assessed the performance of RATs considering specimen types, viral load, the onset of symptoms, and presenting symptoms.We included 214 paired specimens (112 NP and 100 NS SARS-CoV-2 rRT-PCR positive) to the analysis. For NP specimens, the average sensitivity, specificity, and accuracy of the RATs were 87.5%, 98.6%, and 92.8%, respectively, when compared with rRT-PCR. While for NS, the overall kit performance was slightly lower than that of NP (sensitivity 79.0%, specificity 96.1%, and accuracy 88.3%). We observed a progressive decline in the performance of RATs with increased Ct values (decreased viral load). Moreover, the RAT sensitivity using NP specimens decreased over the time of the onset of symptoms.The RATs showed strong performance under field conditions and fulfilled the minimum performance limit for rapid antigen detection kits recommended by World Health Organization. The best performance of the RATs can be achieved within the first week of the onset of symptoms with high viral load.