Flow of a low concentration polyacrylamide fluid solution in a channel with a flat plate obstruction at the entry

Kabir, M.A.,Khan, M.M.K.,Rasul, M.G. The Korean Society of Rheology 2004 Korea-Australia rheology journal Vol.16 No.2

Flow in a channel with an obstruction at the entry can be reverse, stagnant or forward depending on the position of the obstruction. These flow phenomena have potential applications in the control of energy and various flows in process engineering. Parameters that affect this flow inside and around the test channel are the gap (g) between the obstruction geometry and the test channel, the Reynolds number (Re) and the length (L) of the test channel. The influence of these parameters on the flow behavior was investigated using a flat plate obstruction at the entry of the channel. A low concentration polyacrylamide solution (0.018% by weight) showing a powerlaw fluid behavior was used as the fluid in this investigation. The flow phenomena were investigated by the velocity measurement and the flow visualization and their results were compared with numerical simulation. These results of low concentration polyacrylamide solution are also compared with the results of water published elsewhere (Kabir et al., 2003). The maximum reverse flow inside the test channel observed was 20% - 30% of the outside test channel velocity at a g/w (gap to width) ratio of 1 for Reynolds numbers of 1000 to 3500. The influence of the test channel length (L) and the Reynolds number (Re) on the velocity ratio ($V_i$/$V_o$: inside velocity/outside velocity in the test channel) are also presented and discussed here.

Analysis of spray uniformity and distribution by boom height and operating pressure under test bench and field condition

( Sazzadul Kabir ),( Ashrafuzzamn Gulandaz ),( Nasim Reza ),( Mohammod Ali ),( Shaha Nur Kabir ),( Sun-ok Chung ) 한국농업기계학회 2023 한국농업기계학회 학술발표논문집 Vol.28 No.1

Excessive use of pesticide increase production costs and negatively impact on the environment. Increasing spraying effectiveness is one of the major goals of precision variable rate technologies. The technical performance of the nozzle significantly impacts sprayer performance and quality. Analysis of the effects of operating pressure and boom height on spray dispersal and uniformity was the goal of this research. The test bench consisted of four nozzles (NN D-35) and a single-cylinder motor with a four-stroke capacity of 0.72 kW. This self-propelled sprayer was tasted on the ground with 2 km/h speed. Experiments were conducted both in lab and field condition with conventional spray nozzles and water as the test liquid. Tested liquid outflow pressure ranged from 280 to 520 kPa. Depending on the spraying target surface, 35, 45, and 55 cm of working spray boom height were adjusted. The nozzle spacing was 30 cm and the spray angle of the nozzles was 110o. Resultant sprayer nozzle widths with boom heights of 35, 45, and 55 cm caused overlaps of 22.38%, 23.43%, and 24.15% under the lab condition and 24.11%, 26.32%, and 29.37% under field condition. Under the laboratory condition average droplet density levels of 155.38, 159.20, and 168.31 (spots/cm2) were achieved at boom heights of 35, 45, and 55 cm with a speed of 2 km/h, resulting in the spray coverage levels of 23.21%, 26.38%, and 28.35%, respectively. At boom heights of 35, 45, and 55 cm at a speed of 2 km/h, average droplet densities of 138.62, 151.22, and 171.91 (spots/cm2) were obtained under the field yielding spray coverage levels of 24.11%, 26.38%, and 29.37%, correspondingly. Under the both conditions, the 55 cm boom overlapped less than 30%, and the average droplet density and spray coverage in unit area were better than the other two boom heights. It would also be economical and environmentally friendly to use these spraying tools.

Environmental impacts of nanomaterials

Kabir, Ehsanul,Kumar, Vanish,Kim, Ki-Hyun,Yip, Alex C.K.,Sohn, J.R. Elsevier 2018 Journal of environmental management Vol.225 No.-

<P><B>Abstract</B></P> <P>Nanotechnology is currently one of the highest priority research fields in many countries due to its immense potentiality and economic impact. Nanotechnology involves the research, development, production, and processing of structures and materials on a nanometer scale in various fields of science, technology, health care, industries, and agriculture. As such, it has contributed to the gradual restructuring of many associated technologies. However, due to the uncertainties and irregularities in shape, size, and chemical compositions, the presence of certain nanomaterials may exert adverse impacts on the environment as well as human health. Concerns have thus been raised about the destiny, transport, and transformation of nanoparticles released into the environment. A critical evaluation of the current states of knowledge regarding the exposure and effects of nanomaterials on the environment and human health is discussed in this review. Recognition on the potential advantages and unintended dangers of nanomaterials to the environment and human health is critically important to pursue their development in the future.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanotechnology has drawn great interests of researchers due to its immense potentiality. </LI> <LI> Nanotechnology has contributed to the gradual restructuring of diverse technologies. </LI> <LI> The presence of nanomaterials (NMs) can exert adverse effects on the human health. </LI> <LI> In this work, the exposure and effects of NMs is evaluated from various respects. </LI> <LI> The proper evaluation of NMs is offered for their future development and use. </LI> </UL> </P>

Antimicrobial Effects of Chlorogenic Acid and Related Compounds

Kabir, Faisal,Katayama, Shigeru,Tanji, Noriko,Nakamura, Soichiro The Korean Society for Applied Biological Chemistr 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.3

Chlorogenic acid (CGA) is a natural chemical ester composed of caffeic acid and (-)-quinic acid, and is further metabolized into active compounds in the living body. Here, we aimed to provide fundamental information on the antimicrobial action of CGA and related compounds against the Gram-negative bacterium Escherichia coli IFO 3301. Bacteriostatic effects were assessed by spectrophotometry, and bactericidal effects were determined by enumerating viable cells on MacConkey agar plates. CGA and related compounds exhibited specific antimicrobial activity and corresponding reduction in log survival ratio, in which ferulic, isoferulic, benzoic, and hydroxybenzoic acids exhibited obvious antimicrobial activity against E. coli. In a time-kill assay, it was observed that bactericidal effects were associated with treatment time, temperature, and dose. A reduction in log survival ratio was observed at low pH as well as under thermal stress condition. Thus, we demonstrated that CGA and related compounds have not only bacteriostatic effects but also bactericidal effects.

Biocontrol of Late Blight and Plant Growth Promotion in Tomato Using Rhizobacterial Isolates

( Kabir Lamsal ),( Sang Woo Kim ),( Yun Seok Kim ),( Youn Su Lee ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.7

Seven bacterial isolates (viz., AB05, AB10, AB11, AB12, AB14, AB15, and AB17) were derived from the rhizosphere and evaluated in terms of plant growth-promoting activities and the inhibition of Phytophthora infestans affecting tomatoes in Korea. According to 16S rDNA sequencing, a majority of the isolates are members of Bacillus, and a single isolate belongs to Paenibacillus. All seven isolates inhibited P. infestans by more than 60% in vitro. However, AB15 was the most effective, inhibiting mycelial growth of the pathogen by more than 80% in vitro and suppressing disease by 74% compared with control plants under greenhouse conditions. In a PGPR assay, all of the bacterial isolates were capable of enhancing different growth parameters (shoot/root length, fresh biomass, dry matter, and chlorophyll content) in comparison with non-inoculated control plants. AB17-treated plants in particular showed the highest enhancement in fresh biomass with 18% and 26% increments in the root and shoot biomass, respectively. However, isolate AB10 showed the highest shoot and root growth with 18% and 26% increments, respectively. Moreover, the total chlorophyll content was 14%~19% higher in treated plants.

Highly Proton Conductive Zn(II)-Based Metal-Organic Framework/Nafion^® Composite Membrane for Fuel Cell Application

Kabir, M. D. Lutful,Kim, Hee Jin,Choi, Sang-June American Scientific Publishers 2018 Science Of Advanced Materials Vol.10 No.11

Domestic or Multinational penetration strategy of E-commerce Markets: Comparing Daraz.com.bd & Bikroy.com in Bangladesh

Kabir Md Shahriar,Mondol Sonjit Kumer,고일상 한국인터넷전자상거래학회 2023 인터넷전자상거래연구 Vol.23 No.1

Shopping online has also become a new trend as a result of the recent pandemic COVID 19, which has significantly altered consumer purchasing habits and improved public acceptability. However, some e-commerce is still having trouble in achieving satiation while other businesses are growing quickly. Bikroy.com and Daraz.com are Bangladeshi e-commerce platforms where buyers and sellers can connect and exchange things online. These websites were launched in Bangladesh in 2012 and 2015, respectively. Both E-commerce advertises their goods and services on social media platforms like Facebook, Instagram, etc. as m-commerce increasingly gains popularity in Bangladesh. Two examples worth mentioning are Daraz's social media promotion of 15% cash back for Nagad/Bkash Payments and Bikroy’s “Stay Safe in Bikroy.com”. The purpose of the study is to contrast these two e-commerce companies in order to demonstrate why some, like Bikroy, have had trouble attracting customers despite having formerly been the industry leader and a quick mover. At the same time, Daraz.com has experienced significant growth in popularity in the Bangladeshi market despite receiving several product quality complaints. This study uncovers the best business model- and advertising-focused market strategies are most successful in a global setting. Penetration into another marketplace demands the companies to design and implement proper targeting, penetration strategy, business model analysis, and market analysis, and by following the current trend social media marketing strategy. The research provides valuable insights about potential strategies for global reach and different approaches to implement those strategies and recommendations for e-commerce businesses in Bangladesh and contributes to the understanding of e-commerce in developing countries. And Bikroy.com focuses on customer satisfaction while Daraz.com.bd is a cost-driven and value-driven business with a larger revenue and resources and despite challenges, e-commerce has potential in Bangladesh.

APPLICATION OF A HYDRAULIC MODEL FOR PREDICTING THE GENERAL SCOUR: A CASE STUDY FOR ELASIN BRIDGE ON THE DHALESWARI RIVER IN BANGLADESH

KABIR M. MAHBOOB-UL,JAHAN SARWAT,NOOR AHMED ABDULLAH 한국수자원학회 2005 한국수자원학회 학술대회 Vol.2005 No.1

Solar energy: Potential and future prospects

Kabir, Ehsanul,Kumar, Pawan,Kumar, Sandeep,Adelodun, Adedeji A.,Kim, Ki-Hyun Elsevier 2018 RENEWABLE & SUSTAINABLE ENERGY REVIEWS Vol.82 No.1

<P><B>Abstract</B></P> <P>The development of novel solar power technologies is considered to be one of many key solutions toward fulfilling a worldwide increasing demand for energy. Rapid growth within the field of solar technologies is nonetheless facing various technical barriers, such as low solar cell efficiencies, low performing balance-of-systems (BOS), economic hindrances (e.g., high upfront costs and a lack of financing mechanisms), and institutional obstacles (e.g., inadequate infrastructure and a shortage of skilled manpower). The merits and demerits of solar energy technologies are both discussed in this article. A number of technical problems affecting renewable energy research are also highlighted, along with beneficial interactions between regulation policy frameworks and their future prospects. In order to help open novel routes with regard to solar energy research and practices, a future roadmap for the field of solar research is discussed.</P>

Research Trends for Performance, Safety, and Comfort Evaluation of Agricultural Tractors: A Review

Kabir, Md. Shaha Nur,Ryu, Myong-Jin,Chung, Sun-Ok,Kim, Yong-Joo,Choi, Chang-Hyun,Hong, Soon-Jung,Sung, Je-Hoon Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.1

Background: Significant technological development and changes happened in the tractor industries. Contrariwise, the test procedures of the major standard development organizations (SDO's) remained unchanged or with a little modification over the years, demanding new tractor test standards or improvement of existing ones for tractor performance, safety, and comfort. Purpose: This study focuses on reviewing the research trends regarding performance, safety and comfort evaluation of agricultural tractors. Based on this review, few recommendations were proposed to revise or improve the current test standards. Review: Tractor power take-off power test using the DC electric dynamometer reduced human error in the testing process and increased the accuracy of the test results. GPS signals were used to determine acceleration and converted into torque. High capacity double extended octagonal ring dynamometer has been designed to measure drawbar forces. Numerical optimization methodology has been used to design three-point hitch. Numerous technologies, driving strategies, and transmission characteristics are being considered for reducing emissions of gaseous and particulate pollutants. Engine emission control technology standards need to be revised to meet the exhaust regulations for agricultural tractors. Finite Element Analysis (FEA) program has been used to design Roll-Over Protective Structures (ROPS). Program and methodology has been presented for testing tractor brake systems. Whole-body vibration emission levels have been found to be very dependent upon the nature of field operation performed, and the test track techniques required development/adaptation to improve their suitability during standardized assessment. Emphasizes should be given to improve visibility and thermal environment inside the cab for tractor operator. Tractors need to be evaluated under electromagnetic compatibility test conditions due to large growing of electronic devices. Research trends reviewed in this paper can be considered for possible revision or improvement of tractor performance, safety, and comfort test standards.