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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.
( 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.
A study of diamond wire rock cutting process analysis by FEM
Kabir, Mohammed Ruhul,Sagong, Myung,Ahn, Sung-Kwon Korean Tunnelling and Underground Space Associatio 2015 한국터널지하공간학회논문집 Vol.17 No.6
In this paper diamond wire cutting method has been proposed to cut the rock in the tunnel face. Diamond wire saw method could cut the rock from tunnel face with very minor vibration and noise. In this study rock cutting process has been simulated with FEM method by using LS-DYNA explicit non-linear finite element code. Normal load act as an prime factor when cutting the rock surface. For observing the effect of normal load on bead, several experiments has been conducted by varying normal loads on the bead. From each experiment, cutting rate has been calculated to compare the cutting rate with different load conditions. By increasing the normal load on bead, cutting rate increases drastically.
Kabir, Mohammad Humayun,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2010 Applied Biological Chemistry (Appl Biol Chem) Vol.53 No.6
Dehydroascorbate reductase (DHAR) plays an important role in the ascorbate-glutathione cycle in plants by controlling the homeostasis of reactive oxygen species. Expression profiles of two DHAR genes (SlDHAR1 and SlDHAR2) in tomato leaves were analyzed in response to abiotic and oxidative stresses as well as their expression in various organs were investigated under normal growth conditions. Multiple copies of SlDHAR homologues exist in the tomato genome. SlDHAR1 expression was dominant in stems and flowers but moderate in leaves; however, SlDHAR2 induction was strong in stems, leaves, and flowers, and young leaves showed the highest expression of SlDHAR2. Both genes were transcribed after treatment with salt, dehydration, and methyl viologen. Prolonged stress reduced SlDHAR genes expression. The level of hydrogen peroxide increased, and DHAR activity was altered by stress treatment. Results indicate that SlDHAR genes could play a role in multiple stress responses.
Sensor Comparison for Grass Growth Estimation
Kabir, Md. Shaha Nur,Chung, Sun-Ok,Kim, Yong-Joo,Lee, Geung-Joo,Yu, Seung-Hwa,Lee, Kyeong-Hwan,Okayasu, Takashi,Inoue, Eiji FACULTY OF AGRIC PUBLICATIONS-KYUSHU UNIV 2016 Journal of the Faculty of Agriculture, Kyushu Univ Vol. No.
<P>Precision agriculture has been implemented in various cultivation operations for various crops. Recently, autonomous mower tractor with variable rate fertilization has been tried. Variable rate fertilization requires quantification of grass growth level. Objective of this study was to compare the performance of potential sensors under different growth levels and sensor operation conditions. A CCD camera, an ultrasonic module, and an optical reflectance sensor (i.e., Crop Circle) were tested at fields with different grass growth levels. Effects of sensor mounting height and angle were investigated. Effects of vehicle (i.e., mower tractor) vibration and traveling were also investigated: under static, vibration and no traveling, and vibration with traveling conditions. Results showed that sensor mounting height had a little effect on the sensor performance, and grass growth level was successfully quantified. Camera angle of 90 degrees showed the best performance with less noise. The ultrasonic sensor could work with less deviation under static condition, whereas, CCD camera proved the applicability under all operating conditions. Operation condition of the optical reflectance sensor showed a little effect on the grass growth detection results. This study would provide information useful for automated grass growth mapping and variable fertilization recommendation.</P>
A Review of Some Representative Techniques for Controlling the Indoor Volatile Organic Compounds
Kabir, Ehsanul,Kim, Ki-Hyun Korean Society for Atmospheric Environment 2012 Asian Journal of Atmospheric Environment (AJAE) Vol.6 No.3
Poor indoor air quality is now worldwide concern due to its adverse impacts on our health and environment. Moreover, these impacts carry a significant burden to the economy. Various technical approaches (e.g., biological, activated carbon fiber (ACF), photocatlytic oxidation (PCO), etc.) have gained popularity in controlling indoor volatile organic compounds (VOCs). This is because removing indoor VOC sources or increasing ventilation rates is often not feasible or economical. This review provides an overview of the various air purification technologies used widely to improve indoor air quality. Although most of these technologies are very useful to remove indoor VOCs, there is no single fully satisfactory method due to their diversity and presence at the low concentration. To achieve technical innovations and the development of specific testing protocols, one should possess a better knowledge on the mechanisms of substrate uptake at VOC concentrations.
Kabir, E.,Kim, K.H. Pergamon Press ; Elsevier [distribution] 2010 Atmospheric environment Vol.44 No.29
The concentrations of seven odorous volatile organic compounds (VOCs) including styrene (S), toluene (T), xylene (X), methyl ethyl ketone (MEK), isobutyl alcohol (i-BuAl), methyl isobutyl ketone (MIBK), and butyl acetate (BuAc) were measured continuously at hourly intervals from an on-line odor monitoring station in Ansan city, Korea (August 2005 to December 2007). Their concentration data (ppb) exhibited a narrow range of mean values despite large variabilities: 1.33 +/- 8.81, 16.1 +/- 96.6, 3.32 +/- 11.5, 7.45 +/- 10.3, 20.4 +/- 2.38, 1.31 +/- 1.16, and 2.43 +/- 3.02, respectively. However, unlike aromatics, the distribution of other VOCs was characterized by infrequent occurrences, e.g., as large as 97.5% of i-BuAl data below detection limit. Comparison of temporal patterns indicates that aromatic VOCs are the highest in summer, while others tend to peak during fall (or summer). If the relative compositions of these VOCs were compared in terms of odor intensity, their contribution in the study area is unlikely significant as the malodor components. Evaluation of the data suggests that the distribution of the target VOCs should be affected more sensitively by local traffic activities rather than industrial processes in the surrounding area. Nonetheless, the potent roles of these volatile components should not be underestimated with respect to human health.
Response of Calcineurin B-like Protein Kinase Gene in Tomato to Various Abiotic Stresses
Kabir, Mohammad Humayun,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2010 Applied Biological Chemistry (Appl Biol Chem) Vol.53 No.1
This study describes the expression patterns of the CBL interacting protein kinase (SlCIPK) gene in Solanum lycopersicum after treatment with various abiotic stresses, such as salt, dehydration and mechanical wounding. The cDNA of the SlCIPK gene from the tomato leaf encodes 446 amino acids and shows significant homology with other plant CIPK proteins. SlCIPK is a single copy gene in the tomato genome. The organ-specific expression pattern of the SlCIPK gene revealed that the transcript of this gene was present in all tissues examined (roots, stems, leaves and flowers), with strong expression being observed in the roots. Additionally, the SlCIPK gene was upregulated in response to salt, dehydration and wounding. Moreover, SlCIPK was regulated by abscisic acid (ABA) and calcium. Taken together, these results indicate that SlCIPK gene may play a role in the response to abiotic stresses via ABA-mediated calcium signaling.