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Effect of Particulate reinforcement on the Mechanical Properties of Al2024-WC MMCs

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journal of Minerals and Materials Characterization and Engineering 2015年第6期3卷 469-476页

作者： K. punith gowda j. N. Prakash Shivashankare gowda B. Satish Babu Department of Mechanical Engineering East West Institute of Technology Bengaluru India St johns College of Engineering and Technology Yemmiganur India Swarnandhra Institute of Engineering & Technology Narasapur India

The present work reveals the study of mechanical properties of Al2024-Tungsten carbide MMCs containing tungsten carbide (WC) particulates. The reinforcing particulates in the Al2024 alloy were varied from 0% to 5% by weight. The vortex method of cast production was employed to fabricate the MMCs, in which the reinforcement was poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composite so produced was subjected to a series of mechanical tests. The results of this study revealed that as the tungsten carbide particle content was increased, there were significant increases in the ultimate tensile strength, hardness and young’s modulus, compressive strength, accompanied by a reduction in its ductility. An attempt is made in the paper to provide explanations for these phenomena.

关键词： Aluminium 2024 Alloys Tungsten Carbide Stir Casting Mechanical Properties

Effects of firewood harvesting intensity on biodiversity and ecosystem services in shrublands of northern Patagonia

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Forest Ecosystems 2020年第4期7卷 621-634页

作者： Matías G.Goldenberg Facundo j.Oddi juan H.gowda Lucas A.Garibaldi Universidad Nacional de río Negro Instituto de Investigaciones en Recursos NaturalesAgroecología y Desarrollo RuralSan Carlos de BarilocheRío NegroArgentina. Consejo Nacional de Investigaciones Científicas y Técnicas Instituto de Investigaciones en Recursos NaturalesAgroecología y Desarrollo RuralSan Carlos de BarilocheRío NegroArgentina. Laboratorio Ecotono INIBIOMACONICET-Universidad Nacional del ComahueSan Carlos de BarilocheRío NegroArgentina.

Background: Forest management has historically focused on provisioning of goods (e.g. timber, biomass), butthere is an increasing interest to manage forests also to maintain biodiversity and to provide other ecosystemservices (ES).Methods: We evaluated the effects of firewood harvesting intensity on biodiversity and different ES in threecontrasting shrubland sites in northern Patagonia (Argentina). At each site, four harvesting treatments, representingvarious levels of harvest intensity, were randomly assigned to eight permanent sample plots of 31.5m× 45 mduring 2013–***: We found that the effects of increasing harvesting intensity on plant diversity changed from negative topositive (and from nonlinear to more linear responses) with increasing site productivity. Harvesting intensityshowed contrasting effects on variables related to fire protection ecosystem service, since it reduced fuel amount(potentially reducing fire spread) but also reduced live fuel moisture content (potentially increasing flammability) atthe three sites. Two variables related to soil formation and protection ES, leaf litter cover and aerial soil cover,decreased with harvesting intensity at the three ***: We conclude that shrubland management for firewood production may enhance biodiversity withoutcompromising certain important ES. The intensity of harvesting should be determined according to site conditionsand forecasted impacts on biodiversity, fire and soil formation and protection.

关键词： Temperate forest ecosystems Disturbance intensity Plant diversity Ecosystem services

Colour and organic removal of biologically treated coffee curing wastewater by electrochemical oxidation method

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journal of Environmental Sciences 2003年第3期15卷 323-327页

作者： rajesh S. Bejankiwar K.S. Lokesh T.P. Halappa gowda Department of Environmental Engineering S. J. Collge of EngineeringDepartment of Environmental Engineering S. J. Collge of EngineeringDepartment of Environmental Engineering S. J. Collge of Engineering Mysore-570023 Karnataka State IndiaMysore-570023 Karnataka State IndiaMysore-570023 Karnataka State India

The treatment of biologically treated wastewater of coffee-curing industry by the electrochemical oxidation using steel anode was investigated. Bench-scale experiments were conducted for activated sludge process on raw wastewater and the treated effluents were further treated by electrochemical oxidation method for its colour and organic content removal. The efficiency of the process was determined in terms of removal percentage of COD, BOD and colour during the course of reaction. Several operating parameters like time, pH and current density were examined to ascertain their effects on the treatment efficiency. Steel anode was found to be effective for the COD and colour removal with anode efficiency of 0.118 kgCOD\5h -1\5A -1\5m -2 and energy consumption 20.61 kWh\5kg -1 of COD at pH 9. The decrease in pH from 9 to 3 found to increase the anode efficiency from 0.118 kgCOD\5h -1\5A -1\5m -2 to 0.144 kWh\5kg -1 of COD while decrease the energy consumption from 20.61 kWh\5kg -1 of COD to 12.86 kWh\5kg -1 of COD. The pH of 5 was considered an ideal from the present treatment process as it avoids the addition of chemicals for neutralization of treated effluents and also economical with respect to energy consumption. An empirical relation developed for relationship between applied current density and COD removal efficiency showed strong predictive capability with coefficient of determination of 96.5%.

关键词： electrochemical oxidation coffee-curing wastewater steel anode COD colour removal

Electrochemical behavior of paclitaxel and its determination at glassy carbon electrode

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Asian journal of Pharmaceutical Sciences 2014年第1期9卷 42-49页

作者： jayant I.gowda Sharanappa T.Nandibewoor P.G.Department of Studies in Chemistry Karnatak UniversityDharwad 580003Indi

The electrochemical behavior of paclitaxel drug was studied at a glassy carbon electrode in phosphate buffer solutions using cyclic and differential-pulse voltammetric *** oxidation process was shown to be irreversible over the pH range(3.0e10.4)and was diffusion *** of anodic peak potential(E_(p)),anodic peak current(Ipa),scan rate,pH,heterogeneous rate constant(k^(0)),etc have been discussed.A possible electrooxidation mechanism was *** analytical method was developed for the determination of paclitaxel in phosphate buffer solution at pH¼7.0 as a supporting *** anodic peak current varied linearly with paclitaxel concentration in the range 1.0×10^-(6)M to 1.0×10^-(5)M with a limit of detection(LOD)of 1.23×10^(-8)M and limit of quantification(LOQ)of 4.10×10^(-8)*** proposed method was successfully applied to the determination of paclitaxel in pure and real samples.

关键词： Paclitaxel Glassy carbon electrode Voltammetry Injection analysis Urine

Impact of mycotoxins and their metabolites associated with food grains

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Grain & Oil Science and Technology 2023年第1期6卷 1-9页

作者： Chennappa Gurikar D.P.Shivaprasad Luis Sabillón N.A.Nanje gowda Kaliramesh Siliveru ramaiah University of Applied Sciences BangaloreIndia Department of Grain Science and Industry Kansas State UniversityManhattanKSUSA Department of Family and Consumer Sciences New Mexico State UniversityLas CrusesNMUSA

Mycotoxins are secondary toxic metabolites synthesized by numerous filamentous fungi including members of the genus Fusarium,Penicillium,Drechslera,Aspergillus,Claviceps,Monascum,Alternaria,Cephalosporium,Nigrospora,and *** them,Aspergillus and Fusarium species are major plant pathogens recognized to induce infection and produce mycotoxins in food *** than 400 mycotoxins have been documented and among them,aflatoxin,fumonisins,trichothecenes,zearalenone,ochratoxin A,citrinin,ergot alkaloids,and patulin are the most prominent compounds linked to a variety of human and animal health *** Fusarium and Aspergillus belong to a saprophytic group,which can infect and contaminate many crops at pre and post-harvest *** can have a variety of negative effects on health in both humans and *** and their metabolites can cause severe acute poisoning,which can result in death,as well as long-term negative health effects,such as cancer and immune-suppressive disorders in living beings(animals and humans).Mycotoxin contamination of agricultural goods has gained global significance,due to its toxic effects on living beings,as well as its importance to international *** objective is to provide a consolidated information on the potential mycotixs in food grains and their significant impact on the health of the human beings.

关键词： Mycotoxins Aspergillus Fusarium Penicillium Carcinogen Contamination Aflatoxins Fumonisins

Scale Effects of STATSGO and SSUrGO on Flow and Water Quality Predictions

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journal of Water resource and Protection 2013年第3期5卷 266-274页

作者： Prasanna H. gowda David j. Mulla Vinay Nangia Srinivasulu Ale Department of Soil Water and Climate University of Minnesota St. Paul USA International Center for Agricultural research in Dry Areas Amman Jordan Texas A&M AgriLife research Vernon USA USDA-ArS Conservation and Production research Laboratory Bushland USA

Soil information is one of the crucial inputs needed to assess the impacts of existing and alternative agricultural management practices on water quality. Therefore, it is important to understand the effects of spatial scale at which soil databases are developed on water quality evaluations. In the United States, STATSGO (State Soils Geographic) and SSUrGO (Soil Survey Geographic) are the most commonly available soil databases. The purpose of this paper was to quantify the effect of scale by employing STATSGO (1:250,000) and SSUrGO (1:24,000) soil databases in predicting and comparing flow, sediment, nitrate and phosphorus losses for High Island Creek. This watershed is predominately agricultural and located in south-central Minnesota. The ADAPT (Agricultural Drainage and Pesticide Transport), model was calibrated for flow, sediment, nitrate and phosphorus losses over two years (2001-2002) using STATSGO and SSUrGO soil databases. Then the calibrated model was used to evaluate alternative tillage and fertilizer management practices such as adoption of conservation tillage, and rate, timing and method of N- and P-fertilizer applications. Statistical comparison of calibration results with observed data indicated excellent agreement for both soil databases (STATSGO with r2 of 0.95, 0.97, 0.77 and 0.92 and SSUrGO with r2 of 0.90, 0.97, 0.82 and 0.99 for flow, sediment, nitrate and phosphorus losses, respectively). However, STATSGO based predictions of annual nitrate-N losses were consistently greater than those with SSUrGO database and vice-versa for predicted annual phosphorus losses for the alternative management practice that were evaluated.

关键词： Total Maximum Daily Loads Watershed Management Agricultural Best Management Practices ADAPT

Nano-Microencapsulation and Controlled release of Linoleic Acid in Biopolymer Matrices: Effects of the Physical State, Water Activity, and Quercetin on Oxidative Stability

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journal of Encapsulation and Adsorption Sciences 2012年第1期2卷 1-10页

作者： Gilles K. Kouassi Vinod K. Teriveedhi Christopher L. Milby Tarab Ahmad Mark S. Boley Netkal M. gowda ronald j. Terry Department of Chemistry Western Illinois University Macomb USA Department of Physics Western Illinois University Macomb USA

In this study, linoleic acid (LA) was encapsulated in the presence or absence of quercetin into a dual polymer system of whey protein and kappa-carrageenan using power ultrasound. Atomic Force Microscopy (AFM) and FlowCam imaging technology were used for imaging and size determination of nano-and micro-capsules. Differential scanning calorimeter (DSC) was used to determine the glass transition temperature (Tg) of the freeze-dried nanocapsules. In order to examine the effect of water activity (aw) on the release profile of the encapsulated LA, the nanocapsules were equilibrated over saturated salt solution conditions corresponding to the range of aw between 0.333 and 0.769 in evacuated desiccators at room temperature. Gravimetric measurements of the steady state linoleic acid (LA) contents were conducted. The anti-oxidant activity of quercetin and the stability of encapsulated LA toward long term and thermally induced rancidity was investigated. The capsules were in the nanosize regime and 83% of the LA was effectively encapsulated. Furthermore, at aw of 0.764, the highest percentage of LA (74%) was released from the expelling nanocapsules. Quercetin was found to exhibit protective antioxidant effect against time-dependent oxidation and thermally induced rancidity of LA. Water activity values of 0.662 and 0.764 provided ideal humidity and pressure conditions for sustained release of nanoencapsulated LA at room temperature.

关键词： Nanoencapsulation Microencapsulation kappa-Carrageenan Quercetin rancidity Antioxidant

Comparing the Effects of Inputs for NTT and ArcAPEX Interfaces on Model Outputs and Simulation Performance

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journal of Water resource and Protection 2019年第5期11卷 554-580页

作者： Amanda M. Nelson Daniel N. Moriasi Mansour Talebizadeh Haile K. Tadesse jean L. Steiner Prasanna H. gowda Patrick j. Starks USDA-ArS-Grazinglands research Laboratory El Reno OK US

The Agricultural Policy/Environmental eXtender (APEX) model has five different interfaces used to process and build simulation projects. These interfaces utilize different input databases that lead to different model default values. These values can result in different hydrologic, crop growth, and nutrient flow model outputs. This study compared structural and input value differences of the ArcAPEX and Nutrient Tracking Tool (NTT) interfaces. Long-term, water quality data from the rock Creek watershed, located in Ohio were used to determine the impact of the differences on computation time, parameter sensitivity, and streamflow, total nitrogen (TN), and total phosphorus (TP) simulation performance. The input structures were the same for both interfaces for all files except soils, where NTT assigns three soil files per field, rather than a single one in ArcAPEX. As a result, computation times were three times as long for NTT as for ArcAPEX. There were twelve sensitive parameters in both cases, but the order of sensitivity was different. Both interfaces simulated streamflow well, but ArCAPEX simulated evapotranspiration, TN, and TP better than NTT, while NTT simulated crop yields better than ArcAPEX. However, none of the models met all of the performance criteria for either interface. Therefore, more work is needed to ensure models are properly calibrated before being used for scenario analysis. While it is acceptable for the values to be different from the SSUrGO database, there is no documentation explaining the rationale for the modifications from the original source. This is one of the examples that highlights lack of detailed documentation that would be useful to model users. Overall, the results indicate that different interfaces lead to different model simulation results and, therefore, the authors recommend users specify the interface used and any modifications made to the associated databases when reporting model results.

关键词： Agricultural Policy Environmental eXtender (APEX) Calibration Sensitivity Analysis Parameterization Model Databases

Calibration of SWAT2009 Using Crop Biomass, Evapotranspiration, and Deep recharge: Calera Watershed in Zacatecas, Mexico Case Study

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journal of Water resource and Protection 2012年第7期4卷 439-450页

作者： jose r. ávila-Carrasco Francisco Mojarro Dávila Daniel N. Moriasi Prasanna H. gowda Carlos Bautista-Capetillo Francisco G. Echavarria-Cháirez jurgen D. Garbrecht jean L. Steiner Terry A. Howell Edward T. Kanemasu Alan j. Verser Kevin Wagner jairo Hernandez Department of Civil Engineering Boise State University Boise USA Instituto Nacional de Investigaciones Forestales Agricolas y Pecuarias (INIFAP) Zacatecas Calera de V.R. Zac. Mexico Office of Global Programs University of Georgia Georgia USA Texas Water resources Institute Texas A&M Institute of Renewable Natural Resources College Station USA Universidad Autónoma de Zacatecas Zacatecas México USDA-ArS-Conservation and Production research Laboratory Bushland USA USDA-ArS-Grazinglands research Laboratory El Reno USA

Groundwater is the main source of water in the semi-arid Calera watershed, located in the State of Zacatecas, Mexico. Due to increasing population, rapid industrial growth, and increased irrigation to meet growing food demand, groundwater extraction in the Calera watershed are exceeding recharge rates. Therefore, development and evaluation of alter-native water management strategies are needed for sustainable development of the region. The Soil and Water Assessment Tool (SWAT) model was selected for this purpose as it has been used to simulate a wide range of agricultural production, the extensive testing and application in diverse watersheds worldwide, and the potential for future linkage of this model to groundwater models. However, crucial flow data which are commonly used for calibrating hydrologic models are not available in this watershed. This paper describes a novel calibration methodology that uses biomass and water balance approach which has potential for calibration of hydrologic models in ungauged or data-scarce watersheds, which are prevalent in many parts of the world. Estimated long-term annual average actual evapotranspiration (AET), and deep aquifer recharge rates and plant biomass values based on the expert knowledge of researchers and managers in the watershed were used as targets for calibration. The model performance was assessed using the Nash-Sutcliffe effi-ciency coefficient (NSE), coefficient of determination (r2), and percent bias (PBIAS, %) statistics. On average, the calibrated SWAT model yielded annual Nash-Sutcliffe efficiency coefficient values of 0.95, 0.99, and 0.85 for AET, recharge, and biomass, respectively. The coefficient of determination, values for AET, recharge, and biomass were 0.95, 0.94, and 0.99 respectively. The percent bias values of ±2.21%, ±0.18%, and ±0.96% for AET, recharge, and biomass, respectively, indicated that the model reproduced the calibration target values of the three water budget variables within an acce

关键词： SWAT Calera Watershed Scenarios recharge Evapotranspiration runoff Erosion