UVM Verification of an I2C Master Core

With the increasing complexity of IP designs, verification has become quite popular yet is still a significant challenge for a verification engineer. A proper verification environment can bring out bugs that one may never expect in the design. On the contrary, a poorly designed verification environment could give false information about the functioning of the design and bugs may appear on the consumer’s end. Hence, the verification industry is continually looking for more efficient verification methodologies. This paper describes one such efficient methodology implemented on an Inter-Integrated Circuit (I2C) system. I2C packs in itself the powerful features of the Serial Peripheral Interface (SPI) and the universal asynchronous receiver-transmitter (UART), but is comparatively more efficient and uses less hardware for implementation. Also, it can establish secure communication between multiple masters and multiple slaves with minimal wiring. In this project, from a design perspective, the master is a hardware block, and the slave is a verification IP. The methodology used for verification is based on the Universal Verification Methodology (UVM), a class library written in the SystemVerilog language. The paper describes how the verification of an I2C system uses the powerful tools of UVM. The master core has been successfully verified and the coverage goals are met. The effort has been documented in this paper in detail

A Comprehensive Study on Re-arrangement of Modules Based TCT Configurations of Partial Shaded PV Array with Shade Dispersion Method

The conventional Total-Cross-Tied (TCT) Solar photovoltaic (SPV) array configuration has the highest power output as compared to other configurations or topologies in most cases of partial shading. But the performance of TCT configuration is affected under shading conditions, resulting in multiple peaks occurring in the output PV characteristics. To improve the performance of TCT array configuration under different shading scenarios, it is only necessary to reposition or rearrange the PV modules in the TCT Solar PV array based on the arrangement of puzzle numbers, without altering the electrical contacts of the TCT array configuration. The main objective of this study is to investigate the performance of rearrangement of modules in SPV array based new TCT array configurations with shade dispersion technique and compare the global maximum peak power (GMPP) of SPV array, mismatch losses, Fill-Factor, efficiency and number of required electrical connections or ties between array modules with proposed optimal arrangement of modules under shading (non-uniform irradiance) conditions. For this study, one uniform irradiance case and total 14 partial shading patterns were considered. MATLAB/Simulink software was used for modeling and simulation of 6×6 size different rearrangement based TCT array and proposed optimal SPV array configurations.Citation: BALARAJU, V., and Chengaiah, C. (2020). A Comprehensive Study on Re-arrangement of Modules Based TCT Configurations of Partial Shaded PV Array with Shade Dispersion Method. Trends in Renewable Energy, 6, 37-60. DOI: 10.17737/tre.2020.6.1.0011

Mathematical Analysis of Solar Photovoltaic Array Configurations with Partial Shaded Modules

Solar-based photovoltaic (SPV) cells produce power from sunlight through the photovoltaic effect. The yield voltage of a single PV cell is small, so the voltage is extended by interfacing PV cells in series arrangement known as PV module or panel. Solar PV array comprises of series and parallel connections of modules in the grid structure with a few columns and rows. The various kinds of SPV array configurations or topologies are shaped by changing the number of electrical connections between module to module in an array. This paper presents the mathematical examination of 6×6 size regular SPV array configurations, including Total-Cross-Tied, Parallel, Honey-Comb, Series-Parallel, Series, Bridge-Linked types beneath un-shading case, and different proposed shading cases (primarily short narrow, short wide, long narrow, and long wide shadings). The electrical proportionate circuit of the SPV array setups was analyzed by Kirchhoff’s laws at distinctive nodes and loops in a sun powered PV array. The location of global maximum power point (GMPP) was determined hypothetically and distinguished in Matlab/simulation software at various shading conditions.Citation: Raju, V.B., and Chengaiah, C. (2020). Mathematical Analysis of Solar Photovoltaic Array Configurations with Partial Shaded Modules. Trends in Renewable Energy, 6, 121-143. DOI: 10.17737/tre.2020.6.2.0011

Modeling and Performance Investigations of Partially Shaded Solar PV Arrays with Cell Partition Technique based Modules

Solar photovoltaic (PV) modules consist of solar cells connected in series to provide the required output power. The solar PV system is experiencing major challenges, which are mainly due to the partial shadows on the photovoltaic modules leading to mismatching power loss and hot spot problems. Hotspots have become a major cause of PV module failure. The Cell Partition Technique (CPT) is proposed to reduce hotspots and minimize mismatch losses caused by partial shadings. Specifically, each solar PV cell (Full cell) in a solar PV module is divided or partitioned into two half cells (known as Half-Cut Cells or HC) and three equal cells (known as Tri-Cut Cells or TC) in accordance with the proposed technique. The HC and TC types of cells are connected in a strings of series-parallel connection, and bypass diode is placed in middle of the solar PV module to ensure proper operation. The primary aim of this research is to model, evaluate, and investigate the performance of solar PV arrays using new PV modules are developed based on Cell Partition Technique (PVM-CPT), such as half-cut cell modules (HCM), and tri-cut cell modules (TCM) and compared with full-sized cell modules (FCM). These PVM-CPT are connected in Series–Parallel (SP), Total-Cross-Tied (TCT), and proposed static shade dispersion based TCT reconfiguration (SD-TCTR) for the array sizes of 3x4, 4x3 and 4x4, respectively. The purpose is to select the most appropriate solar PV array configurations in terms of the highest global maximum power and thus the lowest mismatch power losses under short and narrow, short and wide, long and narrow, long and wide type of cell level partial shadings. The Matlab/Simulink software is used to simulate and analyze all of the shading cases. The results show that, when compared to conventional module configurations under different shading conditions, the proposed static SD-TCTR arrangement with TC modules (SDTCTR-TCM) exhibits the lowest mismatch power losses and the greatest improvement in array power.Citation:

Preparation and characterization of MAO-Si3N4 composite coating on AZ31B magnesium alloy

Micro arc oxidation process was carried out on AZ 31 B magnesium alloy using alkaline silicate based bath at a constant current density of 0.04 A/cm2. Nano size silicon nitride (Si3N4) particles were added in the bath to obtain MAO- Si3N4 composite coatings. Plain oxide coatings were also prepared for comparison. The developed coatings were characterised for their surface morphology, composition, structure, roughness, nanohardness and wear resistance properties. Field Emission Scanning Electron Microscopy (FE-SEM) analysis of the coating exhibited the irregular porous structure with cracked morphology. Energy Dispersive Analysis of X-ray (EDX) over the surface of the composite coating showed the presence of O (42.8 wt.%), Si (13.2 wt.%), F (4.8 wt.%), Al (0.63 wt.%) and N (7.8 wt.%) with balance Mg respectively. XRD pattern obtained for composite coating revealed the characteristic peaks corresponding to Mg, MgO and Mg2SiO4. Apart from these peaks the presence of a low intensity peak corresponding to Si3N4 was also observed. Composite coating exhibited about 56% increase in nanohardness value (387 HV) compared to plain oxide coating (167 HV). Dry reciprocating wear test experiment was carried out for composite, plain oxide and substrate materials against alumina ball. Wear loss obtained for the composite is 3 times less (10 µms) compared to plain oxide coating which indicated improved wear resistance of the MAO-Si3N4 composite

Characterization of Surface-Treated NiTi Alloy by Various Electrochemical Techniques in Phosphate-Buffered Saline

Sol–gel titania thin film coating was prepared on NiTi surfaces, modified with acidified ferric chloride solution. Nanogrids formed on chemical treatment were uniformly covered with titania coating. Cyclic voltammetry studies in phosphate-buffered saline solution revealed that sol–gel titania-coated surface displayed electrochemical properties which were similar to those observed for pure titanium. During polarization, the passive layer formed on modified NiTi was stable for potentials greater than 0.9 V. The overall resistance measured by electrochemical impedance spectroscopy for sol–gel titania surface was in the order of 10⁵ Ω, which was approximately two orders higher than bare NiTi surface. The current noise analyzed using electrochemical noise measurements was minimum after sol–gel coating, which emphasizes the better protection power of the surface from the attack of corrosive species. Dynamic impedance studies carried out on bare and titania-coated NiTi also supports the results obtained from cyclic polarization

A RAPID RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR THE QUANTITATIVE ESTIMATION OF DABIGATRAN ETEXILATE MESYLATE IN CAPSULES

Objective: To develop a rapid, sensitive, accurate, precise and linear Reverse Phase High Performance Liquid Chromatographic (RP-HPLC) method and validate as per ICH guidelines for the quantitative estimation of Dabigatran etexilate mesylate in capsules.Methods: The optimized method uses a reverse phase column, Waters Symmetry C18 (250 X 4.6 mm; 5μ), a mobile phase of tri ethylammonium phosphate buffer (pH 2.5):acetonitrile in the proportion of 40:60 v/v, flow rate of 1.0 ml/min and a detection wavelength of 313 nm using a UV detector.Results: The developed method resulted in Dabigatran etexilate mesylate eluting at 2.44 min. It exhibited linearity in the range 15-45μg/ml. The precision is exemplified by relative standard deviation of 0.05%. Percentage mean recovery was found to be in the range of 98â€102, during accuracy studies. The limit of detection (LOD) and limit of quantitation (LOQ) was found to be 39.19μg/ml and 118.88μg/ml respectively.Conclusion: A sensitive, rapid, accurate, precise and linear RP-HPLC method was developed and validated for the quantitative estimation of Dabigatran etexilate mesylate in capsules as per ICH guidelines and hence it can be used for the routine analysis in various pharmaceutical industries.Â

Production of cellulase and laccase enzymes by Oudemansiella radicata using agro wastes under solid-state and submerged conditions

Oudemansiella radicata (Relhan ex Fr.) is one of the medicinally important edible mushrooms belonging to Tricholomataceae. In the present study we reported the efficient production of cellulase and laccase enzymes by O. radicata under submerged (SMF) and solid-state (SSF) fermentations. O. radicata had grown well both in submerged and solid-state conditions. Under submerged condition the maximum cellulase activity (490 units / ml / min) was observed. In the case of SSF the maximum cellulase activity was observed as 400 units / ml / min in wheat bran, followed by rice bran (367 units / ml / min). In the case of laccase production, the maximum activity was observed as 1.476 units / ml / min on 14th day at pH 7 under SMF. In solid substrate fermentation the maximum activity was noticed as 25.784 units / ml / min in rice bran. The next higher activity was 11.473 units / ml / min in wheat bran, and the least activity was recorded with saw dust. Higher levels of laccase and cellulase activity were seen in solid-state fermentation than in submerged fermentation. Hence the present results clearly explain that O. radicata is a potential candidate for the production of industrially important enzymes using agro-wastes

XPS Characterization and Microhardness of Heat treated Co-W Coatings Electrodeposited with Gluconate Bath

Thermal stability and effect of heat treatment on electronic structure and microhardness of electrodeposited CoW alloy coatings using gluconate bath was characterized by DSC and XPS. XPS studies demonstrate that as-deposited alloy coating has significant amount of Co and W metals as well as Co2+ and W6+ species. There is a decrease in Co metal concentration in the alloy heated at 600 C and Co is in fully oxidized form when it is heat treated at 800 C. Marginal decrease in W metal concentration and presence of both W6+ and W5+ species are observed when the coating is heated at 600 C, whereas mostly W6+ species along with a little amount of W5+ could be seen in the coating heated at 800 C. Microhardness values of 1017 and 1336 HK are observed when Co−W coatings are heated at 500 and 600 C, respectively and they are comparable with as-deposited hard ch

Role of powder metallurgical processing and TiB reinforcement on mechanical response of Ti-TiB composites

In this work, titanium–titanium boride (Ti–TiB) composites were synthesized by three different powder metallurgical techniques, namely, spark plasma sintering (SPS), hot iso-static pressing (HIP) and vacuum sintering (VS). The mechanical properties of the composites were determined using the nanoindentation technique. The role of the material processing route and TiB reinforcement employed on the mechanical properties of the composites was investigated. The results revealed that the composites processed by SPS possessed improved mechanical properties relative to those of the composites prepared by the HIP and VS techniques. Furthermore, reinforcement of the composites with TiB enhanced the hardness, elastic modulus and contact stiffness, whereas it reduced the fracture toughness and indentation creep