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Naveed Ahmed,Adnan,Umar Khan,Syed Tauseef Mohyud-Din,Ilyas Khan,Kottakkaran Sooppy Nisar 한국자기학회 2020 Journal of Magnetics Vol.25 No.2
The objectives of the research are to explored the heat and mass transport over a paraboloid surface of revolution by taking the effects of Lorentz force, resistive heating and internal heat source. The dimensionless version of the model was attained via similarity transformations. Then, for solution purpose, RK scheme is utilized and performed computations for the flow fields. The influence of different physical quantities on the flow characteristics described comprehensively via graphs. It is examined that the stretching index parameter m opposes the fluid velocity and the temperature enhances for Eckert number. Moreover, significant impacts of the Schmidt number are observed for mass transfer gradient.
Statistical Evaluation of the Multi-Frequency GPS Ionospheric Scintillation Observation Data
Naveed Ahmed,Jiwon Seo 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10
With the growing overdependence on the widely available Global Navigation Satellite System (GNSS) technology, the demand of the secure, reliable and accurate navigation especially for the aviation market has been a major concern of the satellite navigation engineers. The ionospheric scintillation is one of the most dangerous and sophisticated phenomena that not only compromises the accuracy of the receiver’s position, velocity and time (PVT) output but also the reliability of receiver’s performance in such critical situations. The maximum intensity scintillation occurs after every 11 years on average and, therefore, due to lack of available data, there are not enough practical studies to study this phenomenon. In this paper, we study the strong scintillation data collected during the last strong solar maximum event in 2013 at the Ascension Island. The frequency-to-frequency correlation is selected as an important metric to study the fading signals. The observations and the results discussed in the paper are the significant contributions toward the practical study of real ionospheric scintillation data and, hence, provide a strong ground for the future research.
Ahmed, Naveed,Oh, Sang-Eun Elsevier 2018 Sensors and actuators. B Chemical Vol.258 No.-
<P><B>Abstract</B></P> <P>A seven-chamber reactor was developed for a 2-h batch toxicity assessment in water using sulfur-oxidizing bacteria (SOB) based bioassay. The optimum sulfur to water ratio (g:mL) was evaluated using a constant 20 g of sulfur and varying volumes of water at ratios of 1:1, 1:1.5, 1:2, and 1:2.5. Sulfur particles with 20 g sulfur and 20 mL water (1:1 ratio) proved the most efficacious and led to higher electrical conductivity (EC) values. Air flow rates may hinder the effectiveness of EC as the indicator since rates greater than 300 mL/min were shown to lead to higher ECs, most likely through evaporation resulting in higher concentrations. Once optimal conditions were established, the toxicity of Cr<SUP>6+</SUP>, Cu<SUP>2+</SUP>, Zn<SUP>2+</SUP>, Hg<SUP>2+</SUP>, and Ag<SUP>2+</SUP> were assessed. The toxicity values (EC<SUB>50</SUB>) were decreased as exposure time was increased. A 2-h EC<SUB>50</SUB> of 1.78 mg/L for Cr<SUP>6+</SUP>, 5.0 mg/L for Cu<SUP>2+</SUP>, 1.55 mg/L for Zn<SUP>2+</SUP>, 0.21 mg/L for Hg<SUP>2+</SUP>, and 1.76 mg/L for Ag<SUP>2+</SUP> was calculated. The toxicity was compared in decreasing manner as Hg<SUP>2+</SUP> > Zn<SUP>2+</SUP> > Ag<SUP>2+</SUP> > Cr<SUP>6+</SUP> > Cu<SUP>2+</SUP>. The results suggest that SOB was effective for detecting heavy metals in a short period of time (2-h).</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel sulfur-oxidizing bacteria based bioassay was tested in batch reactor. </LI> <LI> Mechanism relies on pH drop and EC rise with SOB growth that can be hindered by toxicants. </LI> <LI> A 2 h EC<SUB>50</SUB> of 1.78 mg/L for Cr<SUP>6+</SUP>, 5.0 mg/L for Cu<SUP>2+</SUP>, 1.55 mg/L for Zn<SUP>2+</SUP>, 0.21 mg/L for Hg<SUP>2+</SUP>, and 1.76 mg/L for Ag<SUP>2+</SUP> was obtained. </LI> <LI> The toxicity was compared in decreasing manner as Hg<SUP>2+</SUP> > Zn<SUP>2+</SUP> > Ag<SUP>2+</SUP> > Cr<SUP>6+</SUP> > Cu<SUP>2+</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Qambrani, Naveed Ahmed,Rahman, Md. Mukhlesur,Won, Seunggun,Shim, Soomin,Ra, Changsix PERGAMON 2017 RENEWABLE AND SUSTAINABLE ENERGY REVIEWS Vol.79 No.-
<P><B>Abstract</B></P> <P>Pyrolysis is one of the most promising technologies for the conversion of biomass into high-value products such as bio-oil, syngas, and biochar in the absence of oxygen. High yield biochar can be produced through torrefaction or slow pyrolysis. The efficiency of biochar production from biomass is highly dependent on the pyrolysis temperature, heating rate, type and composition of feedstock, particle size, and reactor conditions. Application of biochar to agriculture may have a significant effect on reducing global warming through the reduction of greenhouse gas (GHG) emissions and the sequestering of atmospheric carbon into soil. At the same time, biochar can help improve soil health and fertility, and enhance agricultural production. Livestock manure, along with waste-feed residues and bedding materials, is a potential source of biochar. This waste emits significant amounts of GHGs adding to global warming and threatening the environment in other ways. The environmental challenges caused by agricultural and animal-waste disposal can be reduced by recycling the waste using pyrolysis, into biochar, energy, and value-added products. Biochar can act as a sorbent for organic and inorganic contaminants and can efficiently remove these materials from affected waters. Contaminant removal is mainly based on the presence of functional groups and charges on the surface of the biochar. Thus, biochar can help to improve food security by contributing to sustainable production systems and maintaining an eco-friendly environment. This review details the principles and concepts involved in biochar production, the factors that affect biochar quality, as well as the applications of biochar.</P>
구두발표(OC)-농업화학 및 생태,식품분야 : OC-04 ; 황산화 미생물(SOB)을 이용한 토양 독성 평가
나비드 ( Naveed Ahmed Qambrani ),신범수 ( Boem Soo Shin ),오상은 ( Sang Eun Oh ) 한국환경농학회 2014 한국환경농학회 학술대회집 Vol.2014 No.-
A sulfur-oxidizing bacteria (SOB) was successfully applied on the Cd2+ contaminated soil toxicity assessment in batch tests. The monitoring of pH and EC is enough to detect SOB activity. The SOB was found active in different weights of sulfur particles and a 25 g SOB attached sulfur particles were selected to be used in tests. EC and sulfate were found to be correlated with each other, and increasing soil quantity in the reactors decreased the EC change and sulfate production. Contaminated soil having 2 to 64 mg/L Cd2+ concentration was checked. An EC50 of 7.05 mg/L was calculated for Cd2+ contaminated soil. The SOB system was found to be efficient in detecting soil toxicity and can be applied for the evaluation of soil.
아메드 나비드(Naveed, Ahmed T),강은철(Kang, E. C.),이의준(Lee, E. J.) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.06
Photovoltaic (PV) module can generate electricity using sunlight without causing any environmental degradation. Due to higher fossil fuel prices and environmental awareness, PV applications are becoming more popular as clean source of electricity generation. PV output is sensitive to the operating temperature and can be drastically affected in Building Integrated PV (BIPV) systems. PV Solarwall (SWPV) combination and PV systems have been evaluated in this study for improvement in electrical output and system costs. PV modules under forced ventilation. A 75W polycrystalline silicon PV module was fixed on SW in front of the ventilation fan as it was indicated to be the coolest position on the SW in phoenix simulations. The effectiveness of cooling by means of the forced ventilating air stream has been studied experimentally. The results indicate that there appears to be significant difference in temperature as well as electricity output comparing the SWPV and BIPV options. Electrical output power recovered is about 4% during the typical day of the month of February. RETScreen(R) analysis of a 3kW PV system hypothetically located at Taegu has shown that with typical temperature reduction of 15^{{circ}C, it is possible to reduce the simple payback periods by one year. The work described in this paper may be viewed as an appraisal of a SWPV system based on its improved electrical and financial performances due to its ability to operate at relatively lower temperatures.