Inverter Power Stage Connected with PV-Grid

Abstract This paper focuses on the design of the inverter power stage connected with PV-grid which supports the contrived PV system. The increased number of grid connected photovoltaic (PV) inverters gave rise to problems concerning the stability and safety of the utility grid, as well as power quality issues. The proposed systems can overcome these issues and improve standard regulation methods for gird connected PV inverter. The maximum available voltage in the PV string is tracked by the power stage which has been planned and designed in such a way. The tracked voltage is boosted then. The important components to voltage source inverter (VSI) are boost inductor and input capacitor which are calculated. To get a clear sinusoidal output phase voltage of 230 V from a DC capacitance bus projected to deal with 400 V, the important inverter stage parameters have been planned and modeled in Mat lab. Each block stage of the converter is easily understandable by the Simlink of the dual stage DC-AC converter explanation. The control schemes which have been proposed would compromise with the inverter power stage which forms the neat grid system. The existing renewable energy sources in the laboratory are integrated by the proposed control

Fishery and Exploitation of Malabar Grouper, Epinephelus malabaricus (Bloch & Schneider 1801) from Andaman Islands

The fishery and population dynamics of groupers from Andaman Islands were studied from Jan 2010 to Dec 2011 with a special emphasis on Malabar grouper, Epinephelus malabaricus (Bloch & Schneider 1801). The average annual catch of Malabar grouper was 1,296 tonnes contributing to 21.6% of annual grouper landings. Length-weight relationship of Malabar grouper showed that growth was allometric (b=2.96) and relative condition factor (Kn) was 1 and the growth parameters viz., L∞, K and t0 were 124.60 cm, 0.80 and -0.05 respectively. The recruitment pattern was unimodal with one major peak during April to July throughout the study period. The natural mortality (M), fishing mortality (F) and total mortality (Z) were 1.05, 1.48 and 2.53 respectively and exploitation rate (E) was 0.58. The M/K ratio (1.31) was found to be well within the normal range of 1to 2.5. Catch per unit effort varied from 4 to16.5 kg.h-1. The maximum sustainable yield (MSY) was 1,107 tonnes which was lower than the average annual catch (1,296 tonnes), indicating over exploitation. The current study calls for further research in identifying the grouper fishing and spawning aggregation grounds and introduce measures for reducing fishing efforts with input and output controls to sustain the Malabar grouper fishery in Andaman waters

Impact evaluation of marine fisheries interventions among Tribal Fisher Commune of Car Nicobar Island, India

Fisheries and tourism are two important sectors that provide livelihood and employment in the tropical Islands. Andaman and Nicobar group of Islands is a biodiversity hotspot in the Bay of Bengal inhabited by settler population along with indigenous tribal communities. The Nicobar tribal community is one among occupying the Nicobar group of Islands in the majority and are quite socialized tribal communities of the Islands. Agriculture, animal husbandry and fisheries are the major sectors that contribute to the livelihood and nutritional security of the Nicobar tribes. Traditional fishing activities have been a part of their culture over the years however, tribal youths were reluctant in taking up fishing as a profession considering the changing scenario and alternative employment options. To reinstate fisheries as a profession and to improve their livelihood and employment opportunities, interventions were carried out in Car Nicobar Island. The interventions were mainly aimed towards increasing fish catches, to expand their fishing grounds and to sensitize safe fishing and navigation practices. Fishing inputs such as modern fishing boats, GPS and outboard engines were provided as inputs to tribal fishers based on the outcome of an expert consultation meeting. Structured questionnaires were prepared to analyze the impact of the interventions. The results indicated that the interventions led to a significant improvement (p <0.001) in the expansion of their fishing grounds (3.47 ± 0.2 km), reduced time spent to reach the fishing grounds (2.3 ± 0.25 hour) and increased catch per unit effort (7.93 ± 1.23 kg/boat). This study shows that the targeted interventions coupled with awareness and sensitization programmes could make fishing activities profitable, attractive and can motivate the unemployed youths to opt for fishing as a profession

Efficacy of different modes in disseminating Potential Fishing Zone (PFZ) forecasts - a case study from Andaman and Nicobar Islands

Potential Fishing Zone forecasts based on Indian Remote Sensing satellite P4 Ocean Colour Monitor derived chlorophyll concentration and National Oceanographic Aerospace Administration-Advanced Very High Resolution Radiometer derived sea surface temperature were disseminated through different modes viz., Digital display boards, e-mail, telephoning/text messaging, radio, community networking and distribution of print-outs in person to the targeted fishermen and the efficacy was tested. Profound reach of technology dissemination was observed in telephoning/text messaging with an average of 72 users per forecast. Printouts of PFZ maps were distributed to an average of 35 fishermen/boat-masters in person. Digital Display Boards were viewed by 30 fishermen per forecast. E-mail message containing PFZ forecasts were sent to regional fisheries sub-stations of remote islands and it was inferred that an average of 15 fishermen per forecasts were benefitted. Further, PFZ messages were transmitted through All India Radio and Agromet Field Unit for extensive reach all along the inhabited islands. Since the validity period of PFZ forecasts is limited to 2-3 days, near real-time dissemination through telephoning/text messaging was found as an optimal tool for efficient utilisation. Field level constraints in different dissemination modes are illustrated in the paper

Impact of Coastal Pollution on Microbial and Mineral Profile of Edible Oyster (Crassostrea rivularis) in the Coastal Waters of Andaman

The impact of coastal pollution was studied using edible oysters, Crassostrea rivularis as an indicator at two sites viz., North Wandoor (NW) and Phoenix Jetty (PJ) in Port Blair, Andaman. The hydrographic parameters showed that nitrite, nitrate and phosphate concentration were less and dissolved oxygen were more at NW compared to PJ. The oysters were collected from the study sites and biochemical, microbial, mineral profiles and ATPase activities were estimated. ATPase activity was inhibited in the gill tissue of oysters (p\0.05) of PJ sample. Total microbial load in the water and oyster, and coliform bacteria (MPN) in the water were significantly (p\0.05) higher at PJ compared to the NW. There was no significant difference (p[0.05) in the mineral profile of water collected from both the sites. However, calcium and magnesium were more in the oysters collected from NW (p\0.05), and Cu, Zn and Cd were more in PJ samples (p\0.05)

Fisheries governance in the tropical archipelago of Andaman and Nicobar – opinions and strategies for sustainable management

Globally, marine fisheries sector provides livelihood, food security and employment to the fishers engaged in subsistence, artisanal and industrial fishing activities. The dependency on marine fish supplies keeps rising globally leading to intense competition, fishery conflicts and unsustainable fishing practices which threatens the sustainability and leading to the depletion of marine fishery resources. Andaman and Nicobar Islands (ANI) in India is a tropical archipelago cited as an example where marine fishery resources were considered to be highly underutilized vis-a-vis the harvestable potential

Hollow-structured NiCoP nanorods as high-performance electrodes for asymmetric supercapacitors

One-dimensional hollow-structured NiCoP nanorods are synthesized via Kirkendall effect resulting from different diffusion rates of Ni and Co ions at 350 °C, using NaH2PO2 as a phosphorization agent. Various techniques were used to study the formation mechanism of hollow NiCoP nanorods which structure and crystallinity could be effectively tuned by adjusting phosphorization time. Capacitance of NiCoP reaches 273.4 μAh cm−2 at a current density of 30 mA cm−2 with a rate retention of 85.6%. Specific capacitance of an asymmetric supercapacitor cell (ASC) where NiCoP sample was used together with activated carbon reached 264.6 μAh cm−2 at 2 mA cm−2 and decreased to 213.2 μAh cm−2 with current density rising to 30 mA cm−2. The ASC possesses quite high energy- and power densities, compared to previously reported results, which demonstrates applicability of hollow NiCoP nanorods for electrochemical energy storage

Recent advances in hydrothermal carbonisation:from tailored carbon materials and biochemicals to applications and bioenergy

Introduced in the literature in 1913 by Bergius, who at the time was studying biomass coalification, hydrothermal carbonisation, as many other technologies based on renewables, was forgotten during the "industrial revolution". It was rediscovered back in 2005, on the one hand, to follow the trend set by Bergius of biomass to coal conversion for decentralised energy generation, and on the other hand as a novel green method to prepare advanced carbon materials and chemicals from biomass in water, at mild temperature, for energy storage and conversion and environmental protection. In this review, we will present an overview on the latest trends in hydrothermal carbonisation including biomass to bioenergy conversion, upgrading of hydrothermal carbons to fuels over heterogeneous catalysts, advanced carbon materials and their applications in batteries, electrocatalysis and heterogeneous catalysis and finally an analysis of the chemicals in the liquid phase as well as a new family of fluorescent nanomaterials formed at the interface between the liquid and solid phases, known as hydrothermal carbon nanodots

Study on Fatigue Life of Heat-treated Aluminium alloy coated with Castor oil.

This paper involves the study of fatigue life of coated aluminium alloy Al 7075-T651 that is heat-treated under 100oC soaked in castor oil for three days. The specimen after heat treatment is subjected to fatigue test using rotary bending machine for number of cycles to fail under cyclic load of 15kgf, 25Kgf, and 50kgf.The life of the specimen is found and compared with uncoated specimen and improved life in number of cycle is noticed. The crack propagation and its type is analysed using scanning electron microscope for knowing the point of fracture and its initiation to failure

Study on Fatigue Life of Heat-treated Aluminium alloy coated with Castor oil.

This paper involves the study of fatigue life of coated aluminium alloy Al 7075-T651 that is heat-treated under 100oC soaked in castor oil for three days. The specimen after heat treatment is subjected to fatigue test using rotary bending machine for number of cycles to fail under cyclic load of 15kgf, 25Kgf, and 50kgf.The life of the specimen is found and compared with uncoated specimen and improved life in number of cycle is noticed. The crack propagation and its type is analysed using scanning electron microscope for knowing the point of fracture and its initiation to failure