Equilibrium and kinetic studies for removal of malachite green from aqueous solution by a low cost activated carbon

Uma,Yogesh C. Sharma,Sushmita Banerjee 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.4

A low cost activated carbon was synthesized from coconut coir and was applied for the removal of malachite green (MG) from its aqueous solutions. Characterization of the adsorbent was carried out and BET surface area of the adsorbent was found to be 205.27 m2/g. The process of removal of MG was better governed by second order kinetics with a rate constant of 0.21 g mgˉ1 minˉ1 at 323 K. The coefficient of mass transfer was found to be 3.70 x10ˉ5 cm sˉ1. The value of DG8 was found to be negative indicating feasibility and spontaneity of the adsorption process.

Adaptive Distance Protection Scheme Setting in Presence of SVC Using Remote Terminal Unit

Uma Uma Uzubi,Ekwue Arthur,Nmadu Daniel,Eli-Chukwu Ngozi Clara 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

FACTS devices are presently used to improve the power transfer capability of a transmission line and voltage stability of a power system network. Shunt injected current (I sh ) by the Static Var Compensators (SVC) causes underreach or overreach of distance relay when not considered during relay calibration of protection system. This paper presents an adaptive relay setting procedure in the presence of a SVC connected at the midpoint of a transmission line. The remote terminal unit RTU is connected to the SVC terminal via a current transformer (CT) measures the injected shunt current when the SVC is the switch in or out of the network and transferred the measured value to the local station via fi ber optic. The PSCAD/ EMTDC software is used to model an adaptive relay that implements the conventional and adaptive relay system settings. The proposed scheme presents a hybrid distance protection system whose setting is based on the prevailing SVC switching conditions; the relay system was implemented using mho characteristics relay. The results obtained show that the proposed scheme has a high accurate setting

Adaptive Distance Protection Scheme for Mutually Coupled Line

Uma Uzubi Uma,Arthur Ekwue,Emenike Ejiogu 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.1

The availability of zero-sequence current, under normal circumstances, determines the accuracy of the operation of a distance relay which is connected to a mutually coupled parallel line. When this is not available, the system adopts a diff erent compensation factor which if, not properly calculated introduces errors in the relay operation. The proposed adaptive protection scheme, described in this paper, consists of three modular artifi cial neural networks model (ANN). This is developed using the feed-forward nonlinear backpropagation Levenberg–Marquardt algorithm that determines the actual status of the mutually coupled lines. The remote terminal units connected to the current and voltage transformers are used to acquire the appropriate data. The proposed scheme also carefully determines the ground distance element reach settings by calculating the apparent impedance while considering mutual coupling for all practical system confi gurations from the ANN; this eliminates the need for a compensation factor. The results of the apparent impedance (R + jX) calculated by the proposed adaptive and the conventional schemes, showed an average percentage error of (0.06% and 0.02%) and (15% and 41.5%) respectively. Having obtained this result, the performance of the proposed adaptive scheme showed the exact fault location with a higher accuracy when compared with a compensated conventional scheme

Anti-Salmonella activity of a flavonone from Butea frondosa bark in mice

Uma Shankar Mishra,Noton Kumar Dutta,Kaushiki Mazumdar,Santosh Kumar Mahapatra,Pronobesh Chakraborty,Sujata G Dastidar 경희대학교 융합한의과학연구소 2008 Oriental Pharmacy and Experimental Medicine Vol.8 No.4

Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at 50 - 200 μg/ml, while BF-2 (MIC50 400 μg/ml) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The MIC50 of the compound was 50 μg/ml while the MIC90 was 100 μg/ml. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF- 1 as an antibacterial agent may be confirmed further by pharmacological studies. Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at 50 - 200 μg/ml, while BF-2 (MIC50 400 μg/ml) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The MIC50 of the compound was 50 μg/ml while the MIC90 was 100 μg/ml. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF- 1 as an antibacterial agent may be confirmed further by pharmacological studies.

Pervaporation of hydrazine/water with ethylcellulose/4A zeolite mixed matrix membranes

Uma Maheshwari Peddoddi,Dilip Kumar Behara,Suggala Venkata Satyanarayana 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.11

Hydrazine, a hygroscopic liquid, needs to be dehydrated for its utilization as rocket propellant. The conventional processes of separation are cumbersome, as hydrazine forms an azeotrope with water apart from being explosive and highly alkaline. Pervaporation is a well-established safe, energy intensive process for separation of azeotrope mixtures. The selection of polymer for separation of hydrazine and water is of major concern as hydrazine is highly alkaline with pH of ~13.6. Ethyl cellulose (EC) polymer withstands the high pH without any physical deformation or color change. Further, to increase the permselectivity, zeolite 4A nanoparticles were incorporated into the EC polymer matrix. The major focus of the present study was synthesis of zeolite 4A nanoparticles and preparation of ethyl cellulose- zeolite 4A mixed matrix membranes (MMMs). The zeolite particles and membranes were characterized using XRD and FTIR. The characteristics of the membranes were further observed by measuring contact angles. The pervaporation results were quite promising as the total permeate flux and selectivity were 18.35 g/m2h and 8.46 at 36 wt% of feed water concentration with the MMMs with highest zeolite loading. The performance of the MMM’s was comparatively better than pristine EC.

SYNTHESIS OF METASTABLE WURTZITE CZTS NCs AND THEIR TRANSFORMATION INTO KESTERITE CZTS ABSORBER LAYER FOR SOLAR CELL APPLICATION

Uma Ghorpade,Mahesh Suryawanshi,Seung Wook Shin,K. V. Gurav,S. A. Patil,B. S. Pawar,M. G. Gang,Sanjay Kolekar,Jin Hyeok Kim 한국신재생에너지학회 2014 AFORE Vol.2014 No.-

The Relationships between CO2 Emissions, Economic Growth and Life Expectancy

Uma MURTHY,Mohd Shahidan SHAARI,Paul Anthony MARIADAS,Noorazeela Zainol ABIDIN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.2

The issue of the relationship between environmental degradation and human health has been widely addressed by medical doctors. However, economists have sparsely debated it. The release of carbon dioxide (CO2 ) into the air can cause several environmental problems and, thus, it can affect human health. Therefore, it is imperative to examine the effect of CO2 emissions on life expectancy in the D-8 countries (Malaysia, Indonesia, Bangladesh, Nigeria, Egypt, Iran, Pakistan, and Turkey) from 1992 to 2017. The panel ARDL method is employed and, then, the PMG estimator is selected. The results show that economic growth, population growth and health expenditure can significantly and positively affect life expectancy, but CO2 emissions can have a significant and negative effect on life expectancy. Since, the major findings reveal that life expectancy can be explained by CO2 emissions. Hence, it is important to formulate policies on reducing CO2 emissions so that life expectancy will not be affected. Energy diversification policies should be formulated or improved in some countries. This is to ensure that the countries are not highly dependent on non-renewable energy that can harm the environment. The government should increase its expenditure on the health sector to save more lives by extend human lifespan.

Wavelet Relationship between Climate Variability and Deep Groundwater Fluctuation in Thailand’s Central Plains

Uma Seeboonruang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

Groundwater is constantly under direct and indirect pressures from the anthropogenic effects, long-term climate change, and climate variability. This research investigates the association, in the time-frequency domain, between the groundwater fluctuations in Thailand’s Lower Chao Phraya Basin and specific climate variability forces: the El Nino/Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Asian Summer Monsoons (ASM). The analysis was carried out using the wavelet method and the findings presented in the form of the complete, global, and local wavelet spectrums. In addition, the Pearson correlation was utilized to establish the linkages between the groundwater and the climate variability forces. The results indicated that the deep groundwater signals of the Lower Chao Phraya Basin were linked to the ENSO, IOD and ASM with the absolute correlation coefficients in excess of 0.5. Moreover, the recent climatic indices exerted greater influence on the groundwater than in the past, given the former’s correlation coefficients of 0.9 on average. By comparison, the deep groundwater was strongly associated with the recent ENSO and ASM but weakly linked to the IOD, with the absolute coefficients of around 0.5. The findings revealed the resilience of the deep groundwater under such high frequency signal conditions as the seasonal and tidal oscillations. Moreover, the results showed that the groundwater could be an alternative source of water supply during periods of droughts in the region.

A New Fuzzy Logic and GSO based Load balancing Mechanism for Public Cloud

Uma Singhal,Sanjeev Jain 보안공학연구지원센터 2014 International Journal of Grid and Distributed Comp Vol.7 No.5

The recent advances in cloud computing set up well established research in Distributed computing, virtualization, web services, utility computing, have offered many benefits in scalability, cost and efficiency for cloud service users. These advantages are further expected to fulfill the demands of cloud users for cloud services efficiently. This brings the problem of fault tolerance, scalability, efficiency, high availability. Central to these issues require the dynamic and efficient load balancing techniques. In this paper, an effective load balance model is presented for public cloud in which cloud is partitioned with a switch mechanism to choose different load balancing strategy for different load. Fuzzy Logic have been extensively used in various applications such as image processing, data mining, networking, etc. due to its efficient internal architecture and its compatibility to solve various optimization problems. Fuzzy base networks have been observed to produce optimal results in various combinatorial optimization problems. Another important area which provides significant results in solving optimization is the swarm intelligence approach. GSO is observed to have provided significant optimal solution in lesser iterations. In this paper The Fuzzy logic and GSO based load balancing algorithm applied to the load balancing strategy to enhance the utilization and efficiency in the public cloud environment.

Modified Smith Predictor Based Parallel Cascade Control Strategy for Non-Self Regulating Time Delay Processes

Uma, Srinivasan,Rao, Ambati Seshagiri,Kim, JeongTai,Yoo, ChangKyoo The Society of Chemical Engineers, Japan 2011 Journal of chemical engineering of Japan Vol.44 No.8

<P>Modified Smith predictor based parallel cascade control strategy is proposed for enhanced control of non-self regulating processes involving time delays. Modified Smith predictor is integrated in the primary loop of the parallel cascade control structure to enhance the closed loop performance. The proposed structures consist of two control loops, a secondary inner loop and a primary outer loop. The secondary loop controller is designed using the internal model control (IMC) method. Then, the primary loop controllers are designed after identifying the overall primary process model. The primary loop has two controllers meant for set point tracking and good disturbance rejection and designed using direct synthesis method. The primary set point tracking controller is designed as a PID with lag filter and the primary disturbance rejection controller is designed as a PID with lead-lag filter. For comparison, a simple parallel cascade control is also applied to non-self regulating time delay processes. Simulation studies have been carried out on various unstable and integrating processes. The proposed method provides enhanced closed loop performances compared to that of simple parallel cascade control.</P>