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Search Results: 1 - 10 of 20946 matches for " Sumon Kumar Bormon "
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Photocatalytic Degradation of p-Nitrophenol (PNP) in Aqueous Suspension of TiO2  [PDF]
Shafiqul Islam, Sumon Kumar Bormon, Md. Nadim, Kamrul Hossain, Ahsan Habib, Tajmeri Selima Akhter Islam
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.58057
Abstract: The effects of initial concentrations of PNP, doses of TiO2, cations and anions have been investigated to find out the conditions for the maximum degradation of PNP in presence of 254 nm UV light. The rate of photocatalytic degradation of PNP was increased with increasing TiO2 dose until the dose concentration reached at a value 0.4 g/100 mL. Further increase of TiO2 decreased the degradation. The maximum degradation of PNP was found with the catalyst dose 0.4 g/100 mL at pH 3. The degradation of PNP was decreased with increasing of PNP concentration. About 90% degradation of PNP was observed when 1.0 × 10﹣4 M PNP was irradiated for 2 hours in 0.4 g/100 mL of TiO2 suspension. The effect of Cu(II) and Fe(II) ions on the degradation was also investigated. Addition of Cu(II) ions enhances the percent degradation but excess of Cu(II) ions decreases the degradation. Under the same experimental conditions, the presence of \"\" and \"\" is found to be detrimental to the photodegradation of PNP. Hydrogen ion concentration of reaction mixture was found to increase continuously during photodegradation suggesting mineralization of PNP.
Mitigation of High-Tech Products with Probabilistic Deterioration and Inflations  [PDF]
Biswajit Sarkar, Bimal Kumar Sett, Adrijit Goswami, Sumon Sarkar
American Journal of Industrial and Business Management (AJIBM) , 2015, DOI: 10.4236/ajibm.2015.53009
Abstract: This paper describes a deteriorating inventory model with ramp-type demand pattern under stock-dependent consumption rate. The deterioration of the product is considered as probabilistic to make the research a more realistic one. The proposed model assumes partially backorder rate which follows a negative exponential with the waiting time. The effect of inflation and time value of money are incorporated into the model. The purpose of this study is to develop an optimal replenishment policy so that the total profit is maximized. We provide a simple solution procedure to obtain the optimal solutions. Numerical examples along with graphical representations are provided to illustrate the model. Sensitivity analysis of the optimal solution with respect to key parameters of the model has been carried out and the implications are discussed.
A New Approach of Solving Linear Fractional Programming Problem (LFP) by Using Computer Algorithm  [PDF]
Sumon Kumar Saha, Md. Rezwan Hossain, Md. Kutub Uddin, Rabindra Nath Mondal
Open Journal of Optimization (OJOp) , 2015, DOI: 10.4236/ojop.2015.43010
Abstract: In this paper, we study a new approach for solving linear fractional programming problem (LFP) by converting it into a single Linear Programming (LP) Problem, which can be solved by using any type of linear fractional programming technique. In the objective function of an LFP, if β is negative, the available methods are failed to solve, while our proposed method is capable of solving such problems. In the present paper, we propose a new method and develop FORTRAN programs to solve the problem. The optimal LFP solution procedure is illustrated with numerical examples and also by a computer program. We also compare our method with other available methods for solving LFP problems. Our proposed method of linear fractional programming (LFP) problem is very simple and easy to understand and apply.
Performance Evaluation of Unicast and Broadcast Mobile Ad hoc Network Routing Protocols
Sumon Kumar Debnath,Foez Ahmed,Nayeema Islam
Computer Science , 2010,
Abstract: Efficient routing mechanism is a challenging issue for group oriented computing in Mobile Ad Hoc Networks (MANETs). The ability of MANETs to support adequate Quality of Service (QoS) for group communication is limited by the ability of the underlying ad-hoc routing protocols to provide consistent behavior despite the dynamic properties of mobile computing devices. In MANET QoS requirements can be quantified in terms of Packet Delivery Ratio (PDR), Data Latency, Packet Loss Probability, Routing Overhead, Medium Access Control (MAC) Overhead and Data Throughput etc. This paper presents an in depth study of one to many and many to many communications in MANETs and provides a comparative performance evaluation of unicast and broadcast routing protocols. Dynamic Source Routing protocol (DSR) is used as unicast protocol and BCAST is used to represent broadcast protocol. The performance differentials are analyzed using ns2 network simulator varying multicast group size (number of data senders and data receivers). Both protocols are simulated with identical traffic loads and mobility models. Simulation result shows that BCAST performs better than DSR in most cases.
Performance Evaluation of TCP over Mobile Ad-hoc Networks
Foez Ahmed,Sateesh Kumar Pradhan,,Nayeema Islam,,Sumon Kumar Debnath
International Journal of Computer Science and Information Security , 2010,
Abstract: With the proliferation of mobile computing devices, the demand for continuous network connectivity regardless of physical location has spurred interest in the use of mobile ad hoc networks. Since Transmission Control Protocol (TCP) is the standard network protocol for communication in the internet, any wireless network with Internet service need to be compatible with TCP. TCP is tuned to perform well in traditional wired networks, where packet losses occur mostly because of congestion. However, TCP connections in Ad-hoc mobile networks are plagued by problems such as high bit error rates, frequent route changes, multi-path routing and temporary network partitions. The throughput of TCP over such connection is not satisfactory, because TCP misinterprets the packet loss or delay as congestion and invokes congestion control and avoidance algorithm. In this research, the performance of TCP in Ad-hoc mobile network with high Bit Error rate (BER) and mobility is studied and investigated. Simulation model is implemented and experiments are performed using the Network Simulatior-2 (NS-2).
Performance Evaluation of TCP over Mobile Ad hoc Networks
Foez Ahmed,Sateesh Kumar Pradhan,Nayeema Islam,Sumon Kumar Debnath
Computer Science , 2010,
Abstract: With the proliferation of mobile computing devices, the demand for continuous network connectivity regardless of physical location has spurred interest in the use of mobile ad hoc networks. Since Transmission Control Protocol (TCP) is the standard network protocol for communication in the internet, any wireless network with Internet service need to be compatible with TCP. TCP is tuned to perform well in traditional wired networks, where packet losses occur mostly because of congestion. However, TCP connections in Ad-hoc mobile networks are plagued by problems such as high bit error rates, frequent route changes, multipath routing and temporary network partitions. The throughput of TCP over such connection is not satisfactory, because TCP misinterprets the packet loss or delay as congestion and invokes congestion control and avoidance algorithm. In this research, the performance of TCP in Adhoc mobile network with high Bit Error rate (BER) and mobility is studied and investigated. Simulation model is implemented and experiments are performed using the Network Simulatior 2 (NS2).
Predictive Factors of Hyponatremia in Under-Five Severely Malnourished Children with Pneumonia Admitted to a Large Urban Hospital in Dhaka, Bangladesh: A Nested Case-Control Design  [PDF]
Cheryl Kay Zogg, Tahmeed Ahmed, Abu Syeed Golam Faruque, Sumon Kumar Das, Gazi Imran, Mohammod Jobayer Chisti
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.44051
Abstract:

Background: Hyponatremia is the most common electrolyte imbalance encountered in the management of diarrheal children. Common ramifications include cerebral edema and fatal outcomes. However, pediatric data remain lacking, particularly in developmental contexts where resources are limited and associated conditions like malnutrition and pneumonia are common. Aim: This study aimed to evaluate predicting factors associated with hyponatremia in children under five years of age with severe acute malnutrition (SAM) in Bangladesh. Methods: Using a nested case-control design, we compared clinical and laboratory characteristics of children with (n = 61) and without hyponatremia (n = 183) taken from a parent population of all children under five with SAM and clinical or radiological pneumonia admitted to Dhaka Hospital of icddr,b between April 2011 and June 2012 (n = 407). Results: Logistic regression analysis adjusting for potential confounders such as lack of breast feeding, duration of vomiting (days), and severe wasting revealed that older age (OR 1.05, 95%CI 1.02 - 1.07, p = 0.001) (5% increase in the relative odds of hyponatremia for each additional month of age), presence of diarrhea (OR 2.43, 95%CI 1.0 - 6.0, p = 0.05), and difficulty breathing (OR 1.52, 95%CI 1.0 - 2.05, p = 0.05) were significantly associated with hyponatremia. Conclusion: Our data suggest that older age, presence of diarrhea, and difficulty breathing in under-five children with SAM is independent predictors of hyponatremia. These findings underscore the importance of detecting simple clinical predictors early in order to facilitate appropriate management and to prevent potential ramifications of hyponatremia in SAM children, especially in resource-poor settings.

Etiology of Diarrhea among Severely Malnourished Infants and Young Children: Observation of Urban-Rural Differences over One Decade in Bangladesh  [PDF]
Sumon Kumar Das, Mohammod Jobayer Chisti, Sayeeda Huq, Mohammad Abdul Malek, Mohammed Abdus Salam, Tahmeed Ahmed, Abu Syed Golam Faruque
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.43031
Abstract:

There is inadequate information on the etiology of diarrhea in severely malnourished (SM) young children. Thus, the study aimed to determine the etiology of diarrhea among severely malnourished (z score < ?3.00 SD) children in rural and urban Bangladesh. From the database (2000-2011) of Diarrheal Disease Surveillance Systems (DDSS) at rural Matlab and urban Dhaka hospitals of icddr,b, 2234 and 3109 under-5 children were found severely malnourished (underweight, stunted or wasted) respectively. Two comparison groups [moderately malnourished (MM) and well-nourished (WN)] were randomly selected in a ratio of 1:1:1. Children with all categories of SM were more likely to be infected with Vibrio cholerae (rural—11%; urban—15%), Shigella (16%; 9%), Salmonella (1%; 2%) and Campylobacter (3%; 4%); and less likely to have rotavirus (25%; 20%) compared to only one SM category. Isolation rate of Vibrio cholerae was significantly higher among SM both in rural and urban children (7%; 13%) than those of MM (5%; 10%) and WN (2%; 8%) and lower for rotavirus (30%; 31%), (34%; 43%), (35%; 47%) respectively (p < 0.01). However, for Shigella it was only higher among rural SM children (11%) [MM (9%), and WN (8%) (p < 0.01)]. The isolation rate of Salmonella in SM (2%) was similar to that in MM (2%; p = 0.72) but significantly higher than that in WN (1%; p < 0.01) among urban children. Isolation rates of bacterial enteric pathogens were higher but rotavirus was lower in SM children in both rural and urban area with geographical heterogeneity.

Predictors of Meningitis in Under-Fifteen Children Attending an Intensive Care Unit of an Urban Large Diarrheal Disease Hospital in Bangladesh  [PDF]
Farzana Afroze, Tahmeed Ahmed, Shafiqul Alam Sarker, Abu S. G. Faruque, Hasan Ashraf, Pradip Kumar Bardhan, Sumon Kumar Das, Mohammod Jobayer Chisti
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.52022
Abstract:

Background: Data are lack on predicting features of meningitis in diarrheal children although the great clinical importance. Objective: To evaluate clinical and laboratory features in predicting meningitis in under-fifteen children having diarrheal illnesses. Methods: Children aged 1 month to 15 years, admitted in the ICU of the Dhaka Hospital of icddr, b between March 2011 and February 2012 with fever and seizure or altered consciousness and having LP done were enrolled into this analysis. Those children who had abnormal CSF findings [pleocytosis (normal range of leukocyte, 0 - 10/mm3) and/or elevated protein (normal range, 0.10 - 0.45 mg/dl) and low glucose (normal value, 60% of corresponding blood glucose)] were defined as meningitis. Comparison was made between children with (cases = 17) and without meningitis (controls = 66) from our study children. Data were retrospectively collected from SHEBA, an online database system of the Dhaka Hospital of icddr, b. Results: Death was significantly higher among the cases compared to the controls (29% vs. 3%, p = 0.003). In logistic regression analysis, after adjusting for potential confounders, cases frequently had hypoxemia (95% CI 1.55 - 21.93), absent peripheral pulse (95% CI 1.95 - 27.13) and neutrophilia (95% CI 1.13 - 17.00). Conclusion: Our data suggest that children with meningitis had higher case fatality rate. Simple independent predictors of meningitis such as hypoxemia, absent peripheral pulse, and neutrophilia may help clinicians to initiate early and prompt management in order to curve lifelong sequel due to meningitis and death in such patient population especially those in resource poor settings.

Predictors of Death in Under-Five Children with Sepsis Attending an Urban Diarrheal Treatment Centre in Bangladesh  [PDF]
K. M. Shahunja, Abu Sadat Mohammad Sayeem Bin Shahid, Hasan Ashraf, Abu Syeed Golam Faruque, Sumon Kumar Das, Md. Kamruzzaman, Farhana Pervin Flora, Mohammod Jobayer Chisti
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.47090
Abstract:

SETTING: Special Care Ward (SCW) of the Dhaka Hospital of icddr,b, Bangladesh. OBJECTIVE: To evaluate the clinical and laboratory predictors of death in under-five children with clinically defined sepsis presenting with diarrhea. METHODS: We prospectively enrolled all the diarrheal children (n = 151) aged 0 to 59 months with clinical sepsis admitted in the SCW during September’2007 through December’2007. Comparison was made between deaths (n = 23) and survivors (n = 128). Sepsis is defined as presence of inflammation [abnormal WBC count (>11 × 109/L or, <4 × 109/L or, band and neutrophil ratio ≤0.10] plus presence or presumed presence of infection with thermo-instability [hypo (≤35.0) or hyperthermia (≥38.5)], tachycardia, tachypnea, and/or the indications of altered organ function (altered mental status and bounding pulse) in the absence of clinical dehydration or after correction of dehydration. RESULTS: The median (inter-quartile range) age (months) of the children who survived and died was comparable [4.0 (2.0, 12.0) vs. 1.5 (0.8, 10.0); p = 0.703]. In the logistic regression analysis, after adjusting for potential confounders, such as abnormal WBC count, use of intravenous fluid, patient with fatal outcome more often presented with hypernatremia (odds ratio = 16.48, 95% confidence interval = 2.21 - 123.12; p = 0.006), lobar consolidation (odds ratio = 19.9, 95% confidence interval = 2.99 - 132.80; p = 0.002), hypoxemia (odds ratio = 14.78, 95% confidence interval = 1.38 157.90; p = 0.026) and severe under-nutrition (odds ratio = 7.57, 95% confidence interval = 1.24 - 46.11; p = 0.028). CONCLUSIONS: Our data suggest that children under-five with clinical sepsis who present with lobar pneumonia, hypoxaemia, severe acute malnutrition and hyperntaemia are at higher risk of death and identification of these simple factors may help clinicians to take prompt initiative for the aggressive management of such children especially in a resource-limited setting like Bangladesh.

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