Modelling and Analysis of Custom Power Device for Improve Power Quality

Abstract: This paper describes the model and analyzes custom power devices for compensating voltage sag and swell conditions in three phase systems. Faults occurring in power distribution systems or facilities in plants cause the voltage sag or swell. If a fault occurs, it can damage the power system or user’s facility. Sensitivity to voltage sags and swells varies within different applications. For sensitive loads (PLC’s, paper mills etc.), even voltage sags of short duration can cause serious problems in the entire system. Normally, a voltage interruption triggers a protection device, which causes shutdown of the entire system. In order to mitigate power interruptions, this paper proposes a scheme for voltage sag support based on a pulse width modulated autotransformer. The proposed scheme is able to quickly recognize the voltage sag or swell condition, and it can correct the voltage by either boosting the input voltage during voltage sag events or reducing the voltage during swell events.DOI:http://dx.doi.org/10.11591/ijece.v1i1.4

Welding of nickel free high nitrogen stainless steel: Microstructure and mechanical properties

AbstractHigh nitrogen stainless steel (HNS) is a nickel free austenitic stainless steel that is used as a structural component in defence applications for manufacturing battle tanks as a replacement of the existing armour grade steel owing to its low cost, excellent mechanical properties and better corrosion resistance. Conventional fusion welding causes problems like nitrogen desorption, solidification cracking in weld zone, liquation cracking in heat affected zone, nitrogen induced porosity and poor mechanical properties. The above problems can be overcome by proper selection and procedure of joining process. In the present work, an attempt has been made to correlate the microstructural changes with mechanical properties of fusion and solid state welds of high nitrogen steel. Shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), electron beam welding (EBW) and friction stir welding (FSW) processes were used in the present work. Optical microscopy, scanning electron microscopy and electron backscatter diffraction were used to characterize microstructural changes. Hardness, tensile and bend tests were performed to evaluate the mechanical properties of welds. The results of the present investigation established that fully austenitic dendritic structure was found in welds of SMAW. Reverted austenite pools in the martensite matrix in weld zone and unmixed zones near the fusion boundary were observed in GTA welds. Discontinuous ferrite network in austenite matrix was observed in electron beam welds. Fine recrystallized austenite grain structure was observed in the nugget zone of friction stir welds. Improved mechanical properties are obtained in friction stir welds when compared to fusion welds. This is attributed to the refined microstructure consisting of equiaxed and homogenous austenite grains

Ballistic behavior of boron carbide reinforced AA7075 aluminium alloy using friction stir processing – An experimental study and analytical approach

AbstractHigh strength-to-weight ratio of non-ferrous alloys, such as aluminium, magnesium and titanium alloys, are considered to be possible replacement of widely accepted steels in transportation and automobile sectors. Among these alloys, magnesium is self explosive and titanium is costlier, and aluminium is most likely to replace steels. Application of aluminium or its alloys is also thought of as an appropriate replacement in defence field, especially to enhance the easiness in mobility of combat vehicles while maintaining the same standard as that of conventional armour grade steels. Hence most of the investigations have been confined to aluminium or its alloys as base material and open an era of developing the newer composite materials to address the major limitation, i.e. tribological properties. The surface composites can be fabricated by incorporating the ceramic carbides like silicon carbide, carbides of transition metals and oxides of aluminium using surface modification techniques, such as high energy laser melt treatment, high energy electron beam irradiation and thermal spray process which are based on fusion route. These techniques yield the fusion related problems, such as interfacial reaction, pin holes, shrinkage cavities or voids and other casting related defects, and pave the way to need of an efficient technique which must be based on solid state. Recently developed friction stir processing technique was used in the present investigation for surface modification of AA7075 aluminum alloy, which is an alternative to steels. In the present investigation, 160 μm sized boron carbide powder was procured and was reduced to 60 μm and 30 μm using high energy ball mill. Subsequently these powders were used to fabricate the surface composites using friction stir processing.Ballistic performance testing as per the military standard (JIS.0108.01) was carried out. In the present work, an analytical method of predicting the ballistic behavior of surface composites was developed. This method was based on energy balance, i.e., the initial energy of impact is same as that of energy absorbed by multi layers. An attempt also has been made to validate the analytical results with the experimental findings. Variation between the analytical and experimental results may be accounted due to the assumptions considering such as isotropic behavior of target and shearing area of contact as cylindrical instead of conical interface As the analytical model yields the ballistic performance in the closer proximity of experimentally obtained, it can be considered to be an approximation to evaluate the ballistic performance of targets

Role of Threaded Tool Pin Profile and Rotational Speed on Generation of Defect Free Friction Stir AA 2014 Aluminium Alloy Welds

Influence of threads on tool pin and rotational speeds on defect occurrence in friction stir welding (FSW) of aluminum alloy AA 2014 T6 plates has been studied. The effect of FSW forces on the evolution of mechanistic defects, caused in turn through a variation in heat generation during the process has also been examined. In case of conical tool pin, relatively lower rotational speeds resulted in unbounded zones and micro defects while high speeds caused excessive flash, thereby resulting in surface defects and voids inside the weld. The FSW joints were defect-free at moderate speeds, hinting an optimum heat generation and flow. Reaction forces on the tool pin, in the welding direction, were correlated with the defect formation. Tools equipped with a threaded conical pin profile resulted in sound welds, irrespective of the tool rotational speeds in the entire range of 400 rpm - 2400 rpm. The threaded conical pin, with a relatively larger frictional area, may be contributing to higher levels of heat generation compared to a plain conical pin. Further, positive displacement of the hot plasticised material by the threads will carry away excess heat from the advancing-to-the-retracting side and simultaneously downwards, thus confining all heat within the weld zone.

Preparation and storage stability of amla (Phyllanthus emblica) based instant pulihora mix - a South Indian traditional food condiment

Amla (Phyllanthus emblica Linn) is an important crop, indigenous to Indian subcontinent, which is used in alternative medicine, health foods and herbal products. An attempt was made to add value to the highly perishable and seasonable raw material and produce a convenient, shelf stable instant mix for south Indian cuisines. The standardized instant amla pulihora mix (APM) consisted of amla powder (AP, 26%), roasted ground nuts, bengal gram, black gram, green chili, salt (18%) and spices. The titrable acidity of amla powder and amla pulihora mix was 15.1 and 6.4%, respectively. Amla pulihora mix was a rich source of Ca (191.18 mg/100 g), Fe (21.19 mg/100 g) and a considerable amount of proteins (11.2%). The total polyphenol content in amla powder and the amla pulihora mix was found to be 9989 and 3093 mg/100 g, respectively. HPLC analysis revealed that tannic acid and ascorbic acid contents of amla powder were 8102.1, 1601.21 mg/100 g, respectively, and ascorbic acid in amla pulihora mix was found to be 440.21 mg/100 g. Retention of ascorbic acid was higher in the amla pulihora mix (84%), when compared to amla powder (22%), over a storage period of six months. The antioxidant activity (IC50) of amla powder and the amla pulihora mix, as assayed by DPPH and ABTS, were 0.7 and 0.2 mg/ml and 0.28 and 0.17 mg/ml, respectively. Sensory evaluation of the amla pulihora mix indicated that the product was highly acceptable, when mixed with cooked rice in the ratio of 1: 6.9 w/w. The shelf-life of the product was 6 months with a sensory acceptability score of 8. The equilibrium moisture content- relative humidity studies indicated that both the amla powder and amla pulihora mix were non-hygroscopic and stable at room temperature (28±2 °C) up to 6 months when packed in metalized polyester polyethylene pouches. Microbiological analysis indicated both products as safe for consumption up to 6 months storage

Tissue culture-independent in planta transformation strategy: an Agrobacterium tumefaciens-mediated gene transfer method to overcome recalcitrance in cotton (Gossypium hirsutum L.)

The major constraint in cotton improvement has been the recalcitrance of cotton varieties to tissue culture. Alternate methods that avoid/ minimize tissue culture would be beneficial for the improvement of cotton. In this report, transgenic cotton plants have been produced by a tissue-culture independent Agrobacterium tumefaciens - mediated transformation procedure. Agrobacterium strain LBA4404 harboring the binary vector pKIWI105 that carries the genes for β-glucuronidase (GUS) and neomycin phosphotransferase (npt II) was used for transformation. Apical meristem of the differentiated embryo of the germinating seedling is infected with Agrobacterium. Since the transgene is integrated into the cells of already differentiated tissues, the T0 plants will be chimeric and stable integration can be seen only in the T1 generation. The first proof of transformability in the T0 generation was indicated by the GUS histochemical analysis of the seedlings, five days after co-cultivation and subsequently in the pollen and lint. T1 transformants were identified by PCR analysis and subsequently confirmed by Southern. Three plants (T1) with single copy insertions were selected for continuing into the next generations. Molecular characterization and GUS expression analysis (histochemical and fluorimetric) of the T1, T2 and T3 generation suggested the feasibility of the method to generate transgenic plants in cotton

GR-183 - Deep Learning Search Engine

Deep Learning Information Retrieval (IR) is a booming area of research. Research in this field focuses on retrieving the most relevant search results based on the meaning of the search result, not just the keywords. The state-of-the-art technologies generally involve taking existing deep neural networks (such as Universal Sentence Encoder, or Google’s BERT), and training them to rank search results. However, some search engines make use of text matching algorithms (like Best Match 25). These algorithms work by taking into account the term frequency and other word patterns and work surprisingly well. The most common problem when it comes to Machine Learning is over-fitting. Even if the model gives better search results for programming-related questions, that doesn’t mean that it’ll work for searching the research articles. Generally, machine learning-based models are often slow and not scalable. In this project, we tackle all these problems by using the deep learning networks and approximate nearest neighbor search to implement the search engine that accurately ranks the search results based on the given query with a rapid and scalable solution. This model accepts not only text as input but also images as input. The image data is processed through the Image Captioning model that generates the text. This work uses the 200,000 Jeopardy! Questions and MS COCO datasets

Solar PV and Battery Storage Integration System Using Three Level NPC Inverter

In this work, another setup of a three-level neutral point-clipped (NPC) inverter that can incorporate sun powered photovoltaic (PV) with battery stockpiling in a lattice associated framework is proposed. The quality of the proposed topology lies in a novel, expanded unbalance three-level vector tweak strategy that can create the right ac  voltage under lopsided dc voltage conditions. This venture shows the plan investigation of the proposed arrangement and the hypothetical structure of the proposed adjustment system. Another control calculation for the proposed framework is additionally introduced keeping in mind the end goal to control the power conveyance between the sun powered PV, battery, and network, which at the same time gives most extreme power point following (MPPT) operation for the sunlight based PV. In this venture fuzzy controller used to lessened the harmonic distortion when contrasted with the PI controller. The viability of the proposed procedure is explored by the recreation of a few situations, including battery accusing and releasing of various levels of sun based light. The reenactment performed in MATLAB/SIMULINK condition

Pixelated Interactions: Exploring Pixel Art for Graphical Primitives on a Pin Array Tactile Display

Two-dimensional pin array displays enable access to tactile graphics that are important for the education of students with visual impairments. Due to their prohibitive cost and limited access, there is limited research within HCI and the rules to design graphics on these low-resolution tactile displays are unclear. In this paper, eight tactile readers with visual impairments qualitatively evaluate the implementation of Pixel Art to create tactile graphical primitives on a pin array display. Every pin of the pin array is assumed to be a pixel on a pixel grid. Our findings suggest that Pixel Art tactile graphics on a pin array are clear and comprehensible to tactile readers, positively confirming its use to design basic tactile shapes and line segments. The guidelines provide a consistent framework to create tactile media which implies that they can be used to downsize basic shapes for refreshable pin-array displays