24 research outputs found

    Spatial-Temporal Stochasticity of Electric Vehicles in Integrated Traffic and Power System

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    A penetration of a large number of electric vehicles for charging their batteries in the grid can have a negative impact to the grid. To prevent a negative effect to the grid, the behavior of electric vehicles must be accurately modeled and their charging schedules must be coordinated. Therefore, it is necessary to determine where and how much charge is available in electric vehicles in the distribution system. In this thesis, a state transition algorithm is designed to determine a stochastic model of electric vehicles to simulate electric vehicle movement in an integrated traffic and power network. Dijkstra’s algorithm is used to determine the shortest distance between end-user residential and office areas. An uncoordinated and semi-coordinated charging technique are used to charge electric vehicles at different time intervals at different charging stations based on their driving patterns. Monte Carlo simulation is performed to analyze the effect of uncertainty in driving behavior. Results show that uncoordinated charging techniques generate new peaks in the load profile of each node in the distribution system and cause undervoltage problems in the power network. The semi-coordinated charging technique introduces a delay in the charging time to shift electric vehicle charging loads to off-peak times. Hence, with the semi-coordinated charging method, it is unnecessary to immediately upgrade the distribution network infrastructure to avoid network overloading

    Peace-Building - A Powerful Deterrent to Conflict

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    Vogt-Koyanagi-Harada Disease: A Case Series in a Tertiary Eye Center

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    Purpose. To study the clinical spectrum of Vogt-Koyanagi-Harada (VKH) disease in a tertiary eye center in Nepal. Methods. Baseline demographic details and clinical features of six patients diagnosed as VKH in a tertiary eye center were retrospectively reviewed. Examinations included best corrected visual acuity, intraocular pressure, and slit lamp examination of anterior and posterior segments. Baseline blood investigations, chest X-ray, fundus photography, and fundus fluorescent angiography (FFA) were performed on all the patients. Results. The mean age at presentation was 46±8.43 years with female predominance (83.3%). The disease was complete in 16.7%, incomplete in 16.7%, and probable in 66.7% of the patients. Most cases presented in acute uveitis stage (66.7%). The most common finding in acute cases was serous retinal detachment (66.7%), followed by disc edema (58.3%), whereas in chronic cases, depigmented fundus was the most common. All cases had bilateral presentation. Conclusion. VKH is an important cause of bilateral loss of vision and has a good visual prognosis if aggressive treatment is initiated during the early stages

    Au-TiO2 nanocomposites and efficient photocatalytic hydrogen production under UV-visible and visible light illuminations: a comparison of different crystalline forms of TiO2

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    Au[subscript (~1 wt%)]/TiO[subscript 2(anatase or rutile or P25)] nanocomposites were prepared by the solvated metal atom dispersion (SMAD) method, and the as-prepared samples were characterized by diffuse reflectance UV-visible spectroscopy, powder XRD, BET surface analysis measurements, and transmission electron microscopy bright field imaging. The particle size of the embedded Au nanoparticles ranged from 1 to 10 nm. These Au/TiO[subscript 2] nanocomposites were used for photocatalytic hydrogen production in the presence of a sacrificial electron donor like ethanol or methanol under UV-visible and visible light illumination. These nanocomposites showed very good photocatalytic activity toward hydrogen production under UV-visible conditions, whereas under visible light illumination, there was considerably less hydrogen produced. Au/P25 gave a hydrogen evolution rate of 1600 mol/h in the presence of ethanol (5 volume %) under UV-visible illumination. In the case of Au/TiO[subscript 2] prepared by the SMADmethod, the presence of Au nanoparticles serves two purposes: as an electron sink gathering electrons from the conduction band (CB) of TiO[subscript 2] and as a reactive site for water/ethanol reduction to generate hydrogen gas. We also observed hydrogen production by water splitting in the absence of a sacrificial electron donor using Au/TiO[subscript 2] nanocomposites under UV-visible illumination

    Inhibition and Reduction of Biofilm Production along with Their Antibiogram Pattern among Gram-Negative Clinical Isolates

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    Background. Bacterial biofilm is a significant virulence factor threatening patients, leading to chronic infections and economic burdens. Therefore, it is crucial to identify biofilm production, its inhibition, and reduction. In this study, we investigated biofilm production among Gram-negative isolates and assessed the inhibitory and reduction potential of ethylene diamine tetra acetic acid (EDTA) and dimethyl sulfoxide (DMSO) towards them. In addition, we studied the antimicrobial resistance pattern of the Gram-negative isolates. Methods. Bacterial isolation and identification was done using standard microbiological techniques, following the Clinical and Laboratory Standards Institute (CLSI) guideline, 28th edition. The Kirby–Bauer disk diffusion method was used to determine the antibiotic susceptibility pattern of the isolates, and β-lactamase production was tested via the combination disk method. Biofilm formation was detected through the tissue culture plate (TCP) method. Different concentrations of EDTA and DMSO were used to determine their inhibitory and reduction properties against the biofilm. Both inhibition and reduction by the various concentrations of EDTA and DMSO were analyzed using paired t-tests. Results. Among the 110 clinical isolates, 61.8% (68) were found to be multidrug resistant (MDR). 30% (33/110) of the isolates were extended-spectrum β-lactamase (ESBL) producers, 14.5% (16/110) were metallo-β-lactamase (MBL), and 8% (9/110) were Klebsiella pneumoniae carbapenemase (KPC) producers. Biofilm formation was detected in 35.4% of the isolates. Biofilm-producing organisms showed the highest resistance to antibiotics such as cephalosporins, chloramphenicol, gentamicin, and carbapenem. The inhibition and reduction of biofilm were significantly lower (p < 0.05) for 1 mM of EDTA and 2% of DMSO. Conclusion. Isolates forming biofilm had a higher resistance rate and β-lactamase production compared to biofilm nonproducers. EDTA and DMSO were found to be potential antibiofilm agents. Hence, EDTA and DMSO might be an effective antibiofilm agent to control biofilm-associated infections

    Water Taxation and Subsidy Analysis Based on Consumer Water Use Behavior and Water Sources Inside the Kathmandu Valley

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    Groundwater is a major alternative water source used to cover the deficit of water supplied by Kathmandu Upatyaka Khanepani Limited (KUKL), the authority responsible for water supply inside Kathmandu Valley. The groundwater price relative to that of KUKL affects priority of usage, and hence, groundwater resources sustainability. Therefore, taxation or subsidies on water sources become necessary based on their implication on environment. In this study, we evaluate volumetric water price, including initial investment, operation and maintenance (O&amp;M) cost for different water sources, and compare it with the water price of KUKL, Kathmandu. The results show that shallow groundwater is cheaper than KUKL&#8217;s water. For groundwater sustainability, taxation on shallow groundwater seems necessary. For the recent water use of 97 LPCD (liters per capita per day) the taxation requirement is Nepalese Rupee (NRs.) 320/month (0.35% of total expenditure) if the initial investment for well construction and O&amp;M cost are considered, and NRs. 626 (0.7% of total expenditure) if only O&amp;M cost is considered. On the other hand, rainwater harvesting and recharging, the measures to cope with groundwater exploitation, might need 40% to 50% subsidy for their initial investment

    Water Price Optimization after the Melamchi Water Supply Project: Ensuring Affordability and Equitability for Consumer’s Water Use and Sustainability for Utilities

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    Sustainability of water supply services has been central to the main water supply agenda globally. In order to promote affordable, equitable, and sustainable water supply, this paper proposed a method to set the piped water price inside Kathmandu Valley, Nepal. The Melamchi Water Supply Project (MWSP) is currently under construction inside the valley to tide over the water deficit. Domestic water use and expenditure data were obtained from a household survey of 1500 households. Post-MWSP were developed based upon per capita water use and water price. Equity and affordability were evaluated by comparing the ratio of water expenditure to total expenditure of households (expenditure ratio: ER) in each service area. The expenditure for piped water service and alternate water sources was taken into account to calculate the total water expenditure. Sustainability was measured as the ratio of operation and maintenance cost to the total revenue of the utility (Working ratio: WR). The results show that an increase in water price by approximately 54% over the current price is necessary to meet operation and maintenance costs, assuming the WR to be 0.7. Approximately 30% increase in water use (a minimum of 80 LPCD) can be maintained post MWSP. However, water use of 135 LPCD increased the ER by more than 1%, which was the threshold of water affordability and may cause ground water stress
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