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 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

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

ON SOMEWHAT PAIRWISE FUZZY CONTINUOUS FUNCTIONS

Uma, M.K.,Roja, E.,Balasubramanian, G. The Youngnam Mathematical Society Korea 2007 East Asian mathematical journal Vol.23 No.1

In this paper the concept of somewhat pairwise fuzzy continuous functions and somewhat pairwise fuzzy open functions are introduced. Some interesting properties of these functions are investigated besides giving some characterizations of these functions.

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.

Microcontroller based split mass resonant sensor for absolute and differential sensing

Uma, G.,Umapathy, M.,Kumar, K. Suneel,Suresh, K.,Josephine, A. Maria Techno-Press 2009 Smart Structures and Systems, An International Jou Vol.5 No.3

Two degrees of freedom resonant systems are employed to improve the resonant property of resonant sensor, as compared to a single degree of freedom resonant system. This paper presents design, development and testing of two degrees of freedom resonant sensor. To measure absolute mass, cantilever shaped two different masses (smaller/absorber mass and bigger/drive mass) with identical resonant frequency are mechanically linked to form 2 - Degree-of-Freedom (DOF) resonator which exhibits higher amplitude of displacement at the smaller mass. The same concept is extended for measuring differential quantity, by having two bigger mass and one smaller mass. The main features of this work are the 3 - DOF resonator for differential detection and the microcontroller based closed loop electronics for resonant sensor with piezoelectric sensing and excitation. The advantage of using microcontroller is that the method can be easily extended for any range of measurand.

TIETZE EXTENSION THEOREM FOR ORDERED FUZZY PRE-EXTREMALLY DISCONNECTED SPACES

Uma, M.K.,Roja, E.,Balasubramanian, G. The Youngnam Mathematical Society Korea 2008 East Asian mathematical journal Vol.24 No.3

In this paper, a new class of fuzzy topological spaces called ordered fuzzy pre-extremally disconnected spaces is introduced. Tietze extension theorem for ordered fuzzy pre-extremally disconnected spaces has been discussed as in [9] besides proving several other propositions and lemmas.

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.

ENABLING UNASSISTED VISIBLE SOLAR WATER SPLITTING VIA GREEN AND EFFICIENT EUTECTIC MEDIATED QUANTUM DOT SENSITIZED PHOTOELECTRODES

Uma V. Ghorpade,Jin Hyeok Kim 한국신재생에너지학회 2017 AFORE Vol.2017 No.11

Video of World Festivals as Novelties in Teaching Description Writing Using a Genre-Based Approach

( Uma Maheswari Rajagopalan ) 범태평양응용언어학회 2017 범태평양응용언어학회지 Vol.21 No.1

In order to motivate ESL students and engage them in different tasks effectively, it is necessary to make the tasks novel to the students. As one possible way of introducing novelty in the course, films could be used advantageously. In this study, a writing course integrated with videos of movies and cultural festival of different regions of the world including that of author`s country were used as a novel activity and students` attitudes were investigated through questionnaire and open-ended comments. The students belonged to second year undergraduate course of food and nutrition sciences of a Japanese private university. In addition to the film videos as part of listening activity, students were introduced to writings of different genres such as autobiographical, general description, procedure and argumentative writings using a genre-based approach. Students were first introduced to a model writing followed by deconstructing the model writing based on a set of questions. Next, students were asked to write based on the questions to make an outline of their own writings. Following making an outline in the classroom, students constructed their own one paragraph essays. Effects of learning were assessed through students` engagement in writing and in class questionnaire on the video. It was found that students showed real interest in watching film and cultural festivals videos. With cultural festivals, students were made to make comparison with their own and report describing the interesting feature of the festival. The students were also asked to critically reflect on the festivals themselves. Because of the novelty, students actively engaged in the class making the class interesting to the students. In future, a more detailed curriculum using festivals from different parts of their country along with festivals from different parts of the world could be worth considering.