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.

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.

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.

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

Comparison of Test Standards for the Performance and Safety of Agricultural Tractors: A Review

Kabir, Md. Shaha Nur,Chung, Sun-Ok,Kim, Yong-Joo,Shin, Sung-Hyun Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.3

Purpose: The objective of this paper was to compare test standards regarding the performance and safety of agricultural tractors to identify the differences in test conditions, measurement tolerances, and test procedures. Based on the comparison, some recommendations were proposed for possible revisions or improvements to current tractor test standards. Methods: The test standards and codes of major standards development organizations (SDOs), such as the Organization for Economic Cooperation and Development (OECD), the International Organization for Standardization (ISO), the American Society of Agricultural and Biological Engineers (ASABE), EC type approval, and the board of actions of the Nebraska Tractor Test Laboratories (NTTL), were selected and analyzed. Comparison of the test standards: The ISO provides references for fuel and lubricants for tractor tests, and the OECD provides additional measurements for calculating fuel consumption characteristics during the power take-off (PTO) tests. The ISO, EC type approval, and the ASABE provide PTO protective device and the safety requirements. During drawbar power tests, seven transmission ratios are selected for fully automatic transmissions, according to the OECD. In case of hydraulic lift tests, ISO 789-2 and OECD Code 2 advise the use of a static lift force, while SAE J283 advises the use of additional dynamic lift capacity tests for a better representation of in-field operations. The OECD, the ISO, and EC type approval determine the seat index point (SIP), whereas the ASABE determines the seat reference point (SRP) for roll-over protective structure (ROPS) tests. Diversified measurement tolerances were among the braking performance test standards. The European Union (EU) has developed daily limits for vibration exposures with adaptations from ISO 2631-1. Electromagnetic compatibility evaluations are emerging of high-efficiency tractors due to the long-term conformance to electromagnetic emissions and interferences. Comparisons of tractor test standards discussed in this paper are expected to provide useful information for tractor manufacturers and standards development personnel to improve the performance and safety test standards of tractors.

Carbonyl Emissions during Food Decay from Kimchi, Fish, and Salted Fish

Kabir, Ehsanul,Kim, Ki-Hyun Korean Society for Atmospheric Environment 2008 Asian Journal of Atmospheric Environment (AJAE) Vol.2 No.2

In this study, the emissions of carbonyl compounds as offensive odorants were measured using three food types (Kimchi, fresh fish, and salted fish) as a function of time. Odor samples for each food type, collected at 0, 1, 3, 7, and 14 days, were analyzed by high performance liquid chromatography (HPLC). Only three kinds of carbonyl compounds were quantified above their respective detection limits: formaldehyde, acetaldehyde, and acetone. The emission patterns of these compounds were distinguishable from each other. Formaldehyde tends to peak at the beginning and decrease through time with unique patterns. Conversely, acetaldehyde and acetone seem to increase gradually through time. The results showed that relative patterns of carbonyl emissions were more distinguishable by compound type rather than food type.

Chemical Characteristics of Groundwater in Carbonate Rock Areas of Korea

Kabir, Mohammad Lutful,Park, Youngyun,Lee, Jin-Yong Korean Society of Soil and Groundwater Environment 2014 지하수토양환경 Vol.19 No.2

This study was conducted to understand the chemical characteristics of groundwater in carbonate areas of Korea. In this study, data on pH, electric conductivity (EC), $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ were collected from 97 wells which were installed in various carbonate rock regions of Korea. The pH values ranged from 5.7 to 9.9, and the average value was 7.3. The concentration range showed differences between the maximum value of $HCO_3{^-}$ and the medium to minimum values of $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $Cl^-$, $SO_4{^{2-}}$, and $K^+$ in the study area. The average value of EC was $374{\mu}S/cm$, higher than in granite and gneiss areas, where the value is $176{\mu}S/cm$. Most of the groundwater was type $Ca-HCO_3$, and some was type $Mg-HCO_3$. The relationship between $Ca^{2+}$, $Cl^-$, and $HCO_3{^-}$, respectively, and EC showed relatively significant positive correlations compared to the other dissolved components. However, the determination coefficients for $Mg^{2+}$, $Na^+$, $SO_4{^{2-}}$, and $K^+$ were very low less than 0.2. These results indicate that the source of $Ca^{2+}$ and $Mg^{2+}$ is relatively simple (carbonate dissolution) compared to other sources. The sources of $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ might be not only water-rock interactions, but also irrigation return flow, because many groundwater wells had been developed for irrigation purposes. Subsequently, the influence of agriculture on groundwater chemistry was evaluated using a cumulative plot of $SO_4{^{2-}}$. The threshold value of $SO_4{^{2-}}$ calculated from the cumulative frequency curve was 29.2 mg/L. Therefore, 12.4% of all the groundwater wells were affected by agricultural activity.

Feasibility of Streaming Potential Signal on Estimation of Solute Transport Characteristics

Kabir, Mohammad Lutful,Ji, Sung- Hoon,Lee, Jin-Yong,Koh, Yong- Kwon Korean Society of Soil and Groundwater Environment 2015 지하수토양환경 Vol.20 No.2

The drag of the excess charge in an electrical double layer at the solid fluid interface due to water flow induces the streaming current, i.e., the streaming potential (SP). Here we introduce a sandbox experiment to study this hydroelectric coupling in case of a tracer test. An acrylic tank was filled up with homogeneous sand as a sand aquifer, and the upstream and downstream reservoirs were connected to the sand aquifer to control the hydraulic gradient. Under a steady-state water flow condition, a tracer test was performed in the sandbox with the help of peristaltic pump, and tracer samples were collected from the same interval of five screened wells in the sandbox. During the tracer test, SP signals resulting from the distribution of 20 nonpolarizable electrodes were measured at the top of the tank by a multichannel meter. The results showed that there were changes in the observed SP after injection of tracer, which indicated that the SP was likely to be related to the solute transport.

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>