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.

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

Polyphenolic Contents and Antioxidant Activities of Underutilized Grape (Vitis vinifera L.) Pomace Extracts

Kabir, Faisal,Sultana, Mosammad Shahin,Kurnianta, Heri The Korean Society of Food Science and Nutrition 2015 Preventive Nutrition and Food Science Vol.20 No.3

Grape pomace is an abundant source of underutilized winery by-products. Polyphenols were extracted from grape pomace using cellulase and gluco-amylase enzymes. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Folin-Ciocalteu's assays were used to measure antioxidant activity and total polyphenolic contents. Both cellulase, and gluco-amylase digested grape pomace showed efficient radical scavenging activity. In addition, the total polyphenolic contents of cellulase digested grape pomace showed lower concentrations were effective compared to higher concentrations, whereas glucoamylase enzyme did not show remarkable variations. The DPPH radical scavenging activity and total polyphenolic contents were significantly higher in the cellulase digested grape pomace compared to the gluco-amylase digested and the not digested grape pomace. It is notable that enzymatic digestions were efficient for extracting polyphenols from grape pomace. The underutilized grape pomace polyphenols can be further used for food safety as a natural antioxidant.

Nonlinear numerical simulation of RC columns subjected to cyclic oriented lateral force and axial loading

Kabir Sadeghi 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.4

A nonlinear Finite Element (FE) algorithm is proposed to analyze the Reinforced Concrete (RC) columns subjected to Cyclic Loading (CL), Cyclic Oriented Lateral Force and Axial Loading (COLFAL), Monotonic Loading (ML) or Oriented Pushover Force and Axial Loading (OPFAL) in any direction. In the proposed algorithm, the following parameters are considered: uniaxial behavior of concrete and steel elements, the pseudo-plastic hinge produced in the critical sections, and global behavior of RC columns. In the proposed numerical simulation, the column is discretized into two Macro-Elements (ME) located between the pseudo-plastic hinges at critical sections and the inflection point. The critical sections are discretized into Fixed Rectangular Finite Elements (FRFE) in general cases of CL, COLFAL or ML and are discretized into Variable Oblique Finite Elements (VOFE) in the particular cases of ML or OPFAL. For pushover particular case, a fairly fast converging and properly accurate nonlinear simulation method is proposed to assess the behavior of RC columns. The proposed algorithm has been validated by the results of tests carried out on full-scale RC columns.

Optimization of Estrus Synchronization Protocol for Target Breeding to Decrease Voluntary Waiting Period in Lactating Cows

Kabir, Md. Parvez,Islam, Md. Rashedul,Maruf, Abdulla Al,Shamsuddin, Mohammed,Bari, Farida Yeasmin,Juyena, Nasrin Sultana,Rahman, Md Saidur The Korean Society of Animal Reproduction 2017 Reproductive & developmental biology Vol.41 No.2

Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with $PGF_2{\alpha}$ analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional $PGF_2{\alpha}$ after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of $PGF_2{\alpha}$ and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with $PGF_2{\alpha}$ and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

Upgrading flexural performance of prefabricated sandwich panels under vertical loading

Kabir, M.Z.,Rezaifar, O.,Rahbar, M.R. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.3

3-D wall panels are used in construction of exterior and interior bearing and non-load bearing walls and floors of building of all types of construction. Fast construction, thermal insulation, reduced labor expense and weight saving are the most well pronounced advantage of such precast system. When the structural performance is concerned, the main disadvantage of 3D panel, when used as floor slab, is their brittleness in flexure. The current study focuses on upgrading ductility and load carrying capacity of 3D slabs in two different ways; using additional tension reinforcement, and inserting a longitudinal concentrated beam. The research is carried on both experimentally and numerically. The structural performance in terms of load carrying capacity and flexural ductility are discussed in details. The obtained results could give better understanding and design consideration of such prefabricated system.

Research Articles : Application of Silver Nanoparticles for the Control of Colletotrichum Species In Vitro and Pepper Anthracnose Disease in Field

( Kabir Lamsal ),( Sang Woo Kim ),( Jin Hee Jung ),( Yun Seok Kim ),( Kyong Su Kim ),( Youn Su Lee ) 한국균학회 2011 韓國菌學會誌 Vol.39 No.3

Pepper anthracnose caused by Colletotrichum species is one of the most important limiting factors for pepper production in Korea, its management being strongly dependent on chemicals. The aim of this work was to evaluate the possibilities of using silver nanoparticles instead of commercial fungicides. In this study, we evaluated the effect of silver nanoparticles against pepper anthracnose under different culture conditions. Silver nanoparticles (WA-PR-WB13R) were applied at various concentrations to determine antifungal activities in vitro and in the field. The application of 100 ppm concentration of silver nanoparticles produced maximum inhibition of the growth of fungal hyphae as well as conidial germination in comparison to the control in vitro. In field trials, the inhibition of fungi was significantly high when silver nanoparticles were applied before disease outbreak on the plants. Scanning electron microscopy results indicated that the silver nanoparticles caused a detrimental effect on mycelial growth of Colletotrichum species.

An algorithm for simulation of cyclic eccentrically-loaded RC columns using fixed rectangular finite elements discretization

Kabir Sadeghi,Fatemeh Nouban 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.23 No.1

In this paper, an algorithm is presented to simulate numerically the reinforced concrete (RC) columns having any geometric form of section, loaded eccentrically along one or two axes. To apply the algorithm, the columns are discretized into two macro-elements (MEs) globally and the critical sections of columns are discretized into fixed rectangular finite elements locally. A proposed triple simultaneous dichotomy convergence method is applied to find the equilibrium state in the critical section of the column considering the three strains at three corners of the critical section as the main characteristic variables. Based on the proposed algorithm a computer program has been developed for simulation of the nonlinear behavior of the eccentrically-loaded columns. A good agreement has been witnessed between the results obtained applying the proposed algorithm and the experimental test results. The simulated results indicate that the ultimate strength and stiffness of the RC columns increase with the increase in axial force value, but large axial loads reduce the ductility of the column, make it brittle, impose great loss of material, and cause early failure.

Spatial distribution of <i>Heterodera trifolii</i> in Chinese cabbage fields

Kabir, Md. Faisal,Mwamula, Abraham Okki,Lee, Jae-Kook,Jeong, Mungi,Lee, DongWoon,Park, Jung Joon 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol. No.

<P><B>Abstract</B></P> <P>Although <I>Heterodera trifolii</I> is commonly known as the clover cyst nematode, recently the nematode has been identified as a serious menace for Chinese cabbage growers in highland areas in Korea. Soil samples were collected from two Chinese cabbage fields highly infested with <I>H. trifolii</I> in highland areas of Korea, Jungsun and Samcheok, in 2014 and 2015, respectively. A total of 777 (2 × 2 m sampling area) and 414 (5 × 5 m area) soil samples were collected from Jungsun and Samcheok, respectively. The total cysts, cysts with eggs, number of eggs, and empty cysts were calculated for each sample. Distribution patterns for these variables were characterized using spatial analysis by distance indices (SADIE) and variogram model analysis. The aggregation index for cysts with eggs was higher in Jungsun (89.32) than Samcheok (3.63), which indicated that the cyst population density was higher. However, the spatial association of total cysts versus cysts with eggs was higher in Samcheok. The Gaussian model showed reasonable independent range of the nematode in Jungsun and Samcheok to be approximately 53.66 m and 48.54 m, respectively. The model suggested that each nematode sample should be taken at least 50 m apart in the given areas. Inclusion of this distribution pattern may significantly minimize the number of samples in future sampling methods, which could save time and labor, and initiate management practices by elucidating spatial variability factors that influence crop yield.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregation pattern of <I>H. trifolii</I> was identified from two highly infested fields. </LI> <LI> Semivariogram analysis predicted the independent data range for both fields. </LI> <LI> Independent range from Gaussian model can minimize future sampling number and time. </LI> <LI> Nematode management can be initiated by elucidating spatial variability factors. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>