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

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.

다중 특징 기반 입자필터를 이용한 강건한 영상객체 추적

( Kabir Hossain ),이칠우 ( Chi-woo Lee ) 한국정보처리학회 2012 한국정보처리학회 학술대회논문집 Vol.19 No.2

The main goal of this paper is to develop a robust visual tracking algorithm with particle filtering. Visual Tracking with particle filter technique is not easy task due to cluttered environment, illumination changes. To deal with these problems, we develop an efficient observation model for target tracking with particle filter. We develop a robust phase correlation combined with motion information based observation model for particle filter framework. Phase correlation provides straight-forward estimation of rigid translational motion between two images, which is based on the well-known Fourier shift property. Phase correlation has the advantage that it is not affected by any intensity or contrast differences between two images. On the other hand, motion cue is also very well known technique and widely used due to its simplicity. Therefore, we apply the phase correlation integrated with motion information in particle filter framework for robust tracking. In experimental results, we show that tracking with multiple cues based model provides more reliable performance than single cue.

An evaluation of two calibration procedures using thermal desorption-gas chromatography in the analysis of odorous volatile compounds.

Kabir, Ehsanul,Kim, Ki-Hyun Preston Publications 2011 Journal of Chromatographic Science Vol.49 No.9

<P>In this study, the relative performance of gas chromatography (GC) was investigated with respect to the differences in two types of calibration approaches with a thermal desorption (TD) method: the fixed standard concentration approach (FSC: the comparison of different sample volumes for a given standard) was compared with the fixed standard volume approach (FSV: the comparison of different concentration standards at a fixed loading volume). Gaseous working standards of seven odorants, including methyl ethyl ketone (MEK), butyl acetate, methyl isobutyl ketone, isobutyl alcohol, toluene, xylene, and a reference component, benzene, were prepared at four concentration levels (10-100 ppb). They were then analyzed by controlling the TD-loading volumes at six levels (40-1200 mL). The results derived by these contrasting calibration approaches showed moderate changes in the GC sensitivity, either with an increasing concentration (i.e., FSC), or with an increasing sample loading volume (i.e., FSV). Despite an eccentric trend of MEK, the TD-based analysis was fairly predictable and can be recommended for the analysis of the selected odorants.</P>

An Efficient Approach for Lightpath Restoration in WDM Networks

Kabir, S.M. Humayun,Pham, Van Su,Yoon, Gi-Wan The Korea Institute of Information and Commucation 2008 Journal of information and communication convergen Vol.6 No.1

WDM is an incredibly promising technique in which multiple channels are operated along a single fiber, providing the facilities of terabit per second bandwidth. Thus, the survivability of WDM networks becomes critical for the success of the next generation internet architecture. Despite the fact that the path-based proactive restoration scheme guarantees 100% restoration as it computes a backup light path while the primary light path is being set up, this method results in additional capacity consumption. In this paper, an ideal technique is proposed that modifies the active multi-backup paths method and results in a better restoration scheme. Based on a theoretical analysis, a new method is shown to reduce the number of hopes as well as the restoration time.

A Formula Derivation of Channel Capacity Calculation in a MIMO System

Kabir, S.M.Humayun,Lee, Eun-Ju,Yoon, Gi-Wan The Korea Institute of Information and Commucation 2009 Journal of information and communication convergen Vol.7 No.2

In this letter, we derive a tight closed-form formula for an ergodic capacity of a multiple-input multiple-output (MIMO) for the application of wireless communications. The derived expression is a simple closed-form formula to determine the ergodic capacity of MIMO systems. Assuming the channels are independent and identically distributed (i.i.d.) Rayleigh flat-fading between antenna pairs, the ergodic capacity can be expressed in a closed form as the finite sum of exponential integrals.

A New Optimized Localized Technique of CG Return Stroke Lightning Channel in Forest

Kabir, Homayun,Kanesan, Jeevan,Reza, Ahmed Wasif,Ramiah, Harikrishnan,Dimyati, Kaharudin The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.6

Localization of lightning strike point (LSP) in the forest is modeled to mitigate the forest fire damage. Though forest fire ignited by lightning rarely happens, its damage on the forest is grievousness. Therefore, predicting accurate location of LSP becomes crucial in order to control the forest fire. In this paper, we proposed a new hybrid localization algorithm by combining the received signal strength (RSS) and the received signal strength ratio (RSSR) to improve the accuracy by mitigating the environmental effect of lightning strike location in the forest. The proposed hybrid algorithm employs antenna theory (AT) model of cloud-to-ground (CG) return stroke lightning channel to forecast the location of the lightning strike. The obtained results show that the proposed hybrid algorithm achieves better location accuracy compared to the existing RSS method for predicting the lightning strike location considering additive white Gaussian noise (AWGN) environment.