In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray ...In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90,BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7(municipal waste dumping) and 8(medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5(Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9(urban), 10(sub-urban), 11(rural) while sites-7 and 8(urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites -7 and 8. Values of incremental lifetime cancer risk were from 10to 10showed no carcinogenic health risk by road dusts contaminated with the heavy metals.展开更多
Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surfa...Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020.To compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads.Across Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic zone.EZD values vary from 6-154 m for the study area,and it has an inverse correlation with NPP concentration.EZD is deeper during the summer season and shallower during the wintertime,with a corresponding increase in productivity.Throughout the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern BoB.Long-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open ocean.The findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost re展开更多
In this research, we have projected and carried out a novel fishbone network that shows better performance in the term of minimizing the packet delay with respect to sink speed. Previous study implies that sector angl...In this research, we have projected and carried out a novel fishbone network that shows better performance in the term of minimizing the packet delay with respect to sink speed. Previous study implies that sector angle affects greatly on designing fishbone network. Finite Set of nodes arranges to sense the physical condition of any system is called wireless sensor. Our designed fishbone network can be potentially applied for a wireless sensing system to formulate a whole network. The network is a novel design which has been finalized by comparing sector angle. Analysis takes place by varying packet delay according to sink speed. Future analysis takes place for Quality of Service (QoS) and Quality of Experience (QoE). Latency of Packet and its size is the measurement criteria of any network or service is called Quality of Service (QoS). On the other hand the user experience of using the designed network is called Quality of Experience (QoE). Our designed network has been analyzed in TCP Tracer to find out the latency or packet delay for different users. The user data has been shorted and equated among them for latency with different no of packets. Our proposed spiral fishbone network shows better QoS and QoE. In future more nodes can be added to design extended fishbone network for wireless.展开更多
Ethernet network, standardized by IEEE 802.3, is vastly installed in Local Area Network (LAN) for cheaper cost and reliability. With the emergence of cost effective and enhanced user experience needs, the Quality of S...Ethernet network, standardized by IEEE 802.3, is vastly installed in Local Area Network (LAN) for cheaper cost and reliability. With the emergence of cost effective and enhanced user experience needs, the Quality of Service (QoS) of the underlying Ethernet network has become a major issue. A network must provide predictable, reliable and guaranteed services. The required QoS on the network is achieved through managing the end-to-end delay, throughput, jitter, transmission rate and many other network performance parameters. The paper investigates QoS parameters based on packet size to analyze the network performance. Segmentation in packet size larger than 1500 bytes, Maximum Transmission Unit (MTU) of Ethernet, is used to divide the large data into small packets. A simulation process under Riverbed modeler 17.5 initiates several scenarios of the Ethernet network to depict the QoS metrics in the Ethernet topology. For analyzing the result from the simulation process, varying sized packets are considered. Hence, the network performance results in distinct throughput, end-to-end delay, packet loss ratio, bit error rate etc. for varying packet sizes.展开更多
The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be...The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.展开更多
From the environmental consideration,it would be very interesting to use natural fibers such as banana,jute or coir as reinforcement materials instead of artificial fibers or any kind of synthetic materials.Natural fi...From the environmental consideration,it would be very interesting to use natural fibers such as banana,jute or coir as reinforcement materials instead of artificial fibers or any kind of synthetic materials.Natural fibers have many advantages over synthetic ones.Polypropylene banana fiber composites(PPBC)are prepared using untreated and alkali-treated banana fibers at 10-25%by weight of the fiber loading.The thermal properties of polypropylene natural fiber composites are very important for technological uses.Thermogravimetric measurements show that the incorporation of banana fiber into PP enhances the thermal stability of composites containing treated fibers,in comparison with untreated fibers.A composite of biodegradable polypropylene(PP)reinforced with short banana natural fibers was prepared by melt blending followed by a hot press molding system.The thermal properties of matrix materials were studied using thermogravimetric analyzers TGA units.It is observed that the introduction of short banana fibers slightly improved the thermo oxidative stability of PP-banana composites.Physical and chemical changes occurred through dehydration,phase transition,molecular orientation,crystallinity disruption,oxidation and decomposition,and incorporation of several functional groups.Systematic investigations of the thermal behavior of polymers in gas,vacuum or inert atmosphere give the knowledge of how change takes place in polymers.To understand such changes thermogravimetric analysis(TGA)and thermal analysis(TG)were performed.It is observed reinforcement of short banana fiber leads to little improvement in the thermooxidative stability of PPBC.Due to the enhancement of thermo-mechanical properties,such composites may be used as building materials namely roof materials,selling materials and many other engineering applications.展开更多
In this research, the denoising of speckled SAR image has been done with fuzzy filters (ATMED, TMED, ATMAV & TMAV). SAR image or Synthetic Aperture Radar image consists of the informatics of ISW (Internal solitary...In this research, the denoising of speckled SAR image has been done with fuzzy filters (ATMED, TMED, ATMAV & TMAV). SAR image or Synthetic Aperture Radar image consists of the informatics of ISW (Internal solitary waves). A new technique has been proposed which preserved the edge pixels by fuzzy edge detection method and then altered with the filtered image-pixels by fuzzy filtration for getting the denoised image. The comparative result shows that the proposed filter performs better than the other filtered results in terms of PSNR (41.61 dB), MAE (1.47), MSE (4.54) for TMAVxAPE & SSIM (81%) for ATMEDwAPE. The proposed method in this research shows better SSI (Spackle Suppression Index) value. Therefore the experimental result illustrates that the suggested fuzzy filter is much more capable of simultaneously protecting edges and suppressing speckle noise. This research will be beneficial to remove spackle noise from SAR images and can be used for remote sensing and mapping of surface area of earth.展开更多
The standard specification of IEEE 802.15.4 is called ZigBee Propocol. ZigBee protocol required security, low data transfer rate, power efficient network. In addition, the ZigBee mobility function makes the ZigBee net...The standard specification of IEEE 802.15.4 is called ZigBee Propocol. ZigBee protocol required security, low data transfer rate, power efficient network. In addition, the ZigBee mobility function makes the ZigBee network more interactive and multi-purpose. The ZigBee mobile node has a significant effect on network parameters, namely MAC delay, end-to-end delay, MAC throughput and network load. However, a particular significant ZigBee node affects network data traffic and reduces the strength of the Quality of Service (QoS). The key issues are to analyze the QoS in order to increase overall performance of the network. The study proposes a ZigBee network with the mobile node and fixed node based on a variety of MAC layer settings. The Riverbed Network Simulator (Academic Modeler Release 17.5) is used for configuring and simulating the ZigBee network in a variety of conditions. The simulation results show that ZigBee with a fixed node performs better than the ZigBee mobile node. The ZigBee network with fixed node produces a lower network load and a high ratio of successfully transmitted data. The analysis of this study allows the ZigBee network to be better designed.展开更多
Wireless Sensor Network (WSN) is a special type of communication medium through distributed sensor nodes. Popular wireless sensor nodes like ZigBee have splendid interoperability after IEEE 802.15.4 standardization in...Wireless Sensor Network (WSN) is a special type of communication medium through distributed sensor nodes. Popular wireless sensor nodes like ZigBee have splendid interoperability after IEEE 802.15.4 standardization in the domain of wireless personal area network (WPAN). ZigBee has another great feature mobility that makes the ZigBee network more versatile. The mobility feature of ZigBee mobile nodes has a greater impact on network performance than fixed nodes. This impact sometimes turns into more severe because of network structure and mobility model. This study mainly focuses on the performance analysis of the ZigBee mobile node under Random and Octagonal mobility management model with the Tree routing method. The Riverbed academic modeler is used to design, implement and simulate the ZigBee network under certain conditions. This study also presents a competitive performance analysis based on ZigBee mobile nodes transmitter and receiver characteristics under the observation of the mobility model. This indicates that Octagonal mobility model exhibits better performance than the Random mobility model. This study will constitute a new way for further designing and planning a reliable and efficient ZigBee network.展开更多
There are reports on the use of chemicals like sodium tri polyphosphate (STPP) and foreign materials like pearl tapioca (locally called ‘sagu’), jelly (litchi) to adulterate freshwater prawn (Macrobrachium rosenberg...There are reports on the use of chemicals like sodium tri polyphosphate (STPP) and foreign materials like pearl tapioca (locally called ‘sagu’), jelly (litchi) to adulterate freshwater prawn (Macrobrachium rosenbergii) prior to freeze processing to increase their weight. Studies were, therefore, undertaken to determine the changes in product quality on the use of different concentrations of STPP, sagu and litchi under ice storage condition. Percent weight gain of prawn was 5.46, 18.87 and 23.50 when dipped in 2%, 4% and 6% STPP solution, respectively. In all cases maximum water uptake by prawn muscle was during the first 6 h with fastest weight gain with STPP solutions containing tap water compared to those of ice and tap water. Organoleptic quality of the STPP treated samples became brown and spongy after 8 h of dipping treatment under iced condition. Quality assessment studies conducted after injecting sagu and litchi in prawn muscle showed little or no difference with those of control samples during the first 6 h, which turned whitish and swollen with severe drip loss after 24 h of ice stored condition, indicating characteristics for easy identification of the injected shrimps by organoleptic method.展开更多
Background: CT-scan is a very useful diagnostic tool for the detection of hepatic mass. Objective: The present study was undertaken to determine the CT-scan findings of benign and malignant hepatic mass patients. Meth...Background: CT-scan is a very useful diagnostic tool for the detection of hepatic mass. Objective: The present study was undertaken to determine the CT-scan findings of benign and malignant hepatic mass patients. Methodology: This was a cross sectional study conducted in Radiology and Imaging Department at Mymensingh Medical College Hospital (MMCH), Mymensingh;Dhaka Medical College Hospital (DMCH), Dhaka and Banghabandhu Sheikh Mujib Medical University (BSMMU), Dhaka with the collaboration of Pathology Department of the same institute for histopathological confirmation. This study was carried out from January 2006 to December 2007 for a period of 2 years. The patients who were clinically suspected of having hepatic mass attended in the Radiology and Imaging Department in the above mentioned institutes were included as study population. All the CT-scan findings were recorded. Result: A total number of 50 patients were enrolled for this study. CT-scan was done among 40 males and 10 females with a mean age of 51.28 years old. Hypodensity was found in 17 (60.7%) and 18 (81.8%) cases in malignant and benign hepatic lesions respectively. Ill-defined margin was detected in 12 (42.9%) and 6 (27.3%) cases respectively. Calcification was present on 11 (39.3%) malignant lesion and 6 (27.3%) benign lesions. Pressure effect on biliary apparatus was found in 11 (39.3%) malignant lesions and 1 (4.5%) benign lesions (p < 0.05). Lymphadenopathy was found in 10 (35.7%) malignant lesions and 1 (4.5%) benign lesions (p < 0.05). Conclusion: In conclusion, CT-scan findings of malignant and benign hepatic mass show hypodensity with more contrast enhancement in malignant lesions with more calcification in malignant lesion;however, significant difference is detected in pressure effect on biliary apparatus and lymphadenopathy.展开更多
The main purpose of this study is to find the awareness level as well as the determinants of awareness on HIV/AIDS among the garments workers in Dhaka City, Bangladesh. To do so, 200 garments workers were interviewed ...The main purpose of this study is to find the awareness level as well as the determinants of awareness on HIV/AIDS among the garments workers in Dhaka City, Bangladesh. To do so, 200 garments workers were interviewed through a structured questionnaire using purposive sampling technique. As the statistical tools, univariate analysis was completed to figure out frequency distribution and the binary logistic regression model was used to predict the probability occurrence of the events by fitting data. The results revealed that the majority of the garments workers (63.5%) are very young (18 - 27 years), almost all (97.5%) are literate and most of them (57.0%) used contraceptives. Importantly, most of the respondents (64.0%) had not participated in any type of seminar or workshop related to HIV/AIDS, though almost all the respondents (84.5%) know HIV is a dangerous and life threatening disease. The logistic regression model identified that respondents' education, contraceptive usage, mass media and HIV workshops have statistically significant positive effects on HIV/AIDS awareness. Various media campaigns are strongly suggested to be increased knowledge and awareness to control the spread of HIV as well as STDs among garments workers in Bangladesh.展开更多
Cryptography is the study that provides security service. It concerns with confidentiality, integrity, and authentication. Public key cryptography provides an enormous revolution in the field of the cryptosystem. It u...Cryptography is the study that provides security service. It concerns with confidentiality, integrity, and authentication. Public key cryptography provides an enormous revolution in the field of the cryptosystem. It uses two different keys where keys are related in such a way that, the public key can use to encrypt the message and private key can be used to decrypt the message. This paper proposed an enhanced and modified approach of RSA cryptosystem based on “n” distinct prime number. This existence of “n” prime number increases the difficulty of the factoring of the variable “N” which increases the complexity of the algorithm. In this approach, two different public key and private key generated from the large factor of the variable “N” and perform a double encryption-decryption operation which affords more security. Experiment on a set of a random number provided that the key generation time, analysis of variable “N”, encryption and decryption will take a long time compared to traditional RSA. Thus, this approach is more efficient, highly secured and not easily breakable.展开更多
The HIV/AIDS epidemic has grown on an unprecedented scale since it was first recognized, and presently it is considered as a well known global public health crisis. In making the health policy where millions of popula...The HIV/AIDS epidemic has grown on an unprecedented scale since it was first recognized, and presently it is considered as a well known global public health crisis. In making the health policy where millions of populations are at risk, it is necessary to understand the knowledge level about HIV/AIDS. So, this study aimed at to investigate the knowledge level about HIV/AIDS among the villagers. Data and necessary information were collected from one hundred villagers of Salmanpur from Comilla district, Bangladesh through a structured questionnaire. The collected data were used for univariate analysis, to carry out the description of the variables;and to justify the total score of knowledge about HIV/AIDS among the respondents, Cronbach’s alpha (α) was calculated. The results revealed that almost all the respondents (92.00%) were ever heard about HIV/AIDS and half of them (51.00%) were known it as a communicable disease. Majority of the respondents (62.00%) believed that it is caused by heterosexual relation as well as sex with HIV positive persons. However, a good number of respondents were found unaware about the major causes and preventive ways of AIDS. Less than half of the respondents (45.00%) had medium knowledge (α = 0.34 - 0.66) and only 36.00% had the enough knowledge about HIV/AIDS. The knowledge level is increasing with the increase of education level, and the respondents who involved in agricultural works are found the lowest knowledge level (47.00%) about HIV/AIDS. The villagers were known about HIV/AIDS but they do not have accurate information about the ways in which AIDS virus can or cannot be transmitted. Therefore, effective programs should be taken to increase the knowledge level about HIV/AIDS among the villagers in Bangladesh.展开更多
The Wireless Sensor Network (WSN) is spatially distributed autonomous sensor to sense special task. WSN like ZigBee network forms simple interconnecting, low power, and low processing capability wireless devices. The ...The Wireless Sensor Network (WSN) is spatially distributed autonomous sensor to sense special task. WSN like ZigBee network forms simple interconnecting, low power, and low processing capability wireless devices. The ZigBee devices facilitate numerous applications such as pervasive computing, security monitoring and control. ZigBee end devices collect sensing data and send them to ZigBee Coordinator. The Coordinator processes end device requests. The effect of a large number of random unsynchronized requests may degrade the overall network performance. An effective technique is particularly needed for synchronizing available node’s request processing to design a reliable ZigBee network. In this paper, region based priority mechanism is implemented to synchronize request with Tree Routing Method. Riverbed is used to simulate and analyze overall ZigBee network performance. The results show that the performance of the overall priority based ZigBee network model is better than without a priority based model. This research paves the way for further designing and modeling a large scale ZigBee network.展开更多
China has departed from the East Asian development model by letting inequality rise to a high level, which is now contributing to China＇s current problems of macroeconomic imbalance, declining efficiency of capital, ...China has departed from the East Asian development model by letting inequality rise to a high level, which is now contributing to China＇s current problems of macroeconomic imbalance, declining efficiency of capital, and rising social tensions. If inequality persists, China may get caught in the ＂inequality-trap,＂ which may then lead to the middle income trap （MIT）. Fortunately, China still has the levers to pull to reduce inequality and avoid the MIT. Measures along both the ＂wage route＂ and the ＂redistributive route＂ can be adopted for this purpose. In addition, China may pursue the ＂cooperative route＂ to more equitable distribution.展开更多
This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pi...This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pipe(CFUT)with different geometric properties were tested.To obtain the specimens different class pipes with three different diameters were used to investigate the sensitivity of these columns to various parameters.The effect of each variable on the ultimate strength,ductility and confinement efficiency of the samples was investigated.All specimens were compressed by applying load only to the concrete core to obtain the load-displacement variations and the corresponding deformation mode.A finite element model was developed using the proposed stress-strain variation of confined concrete with UPVC tubes to simulate axial compression of CFUT specimens.According to the results obtained,the effect of the change in diameter-thickness ratio failure stress of concrete limited by(D/t)is obtained and discussed with empirical relationship.Polypropylene fibers were found to slightly increase column strength up to a certain volume fraction,after which the strength generally experienced a decrease.展开更多
Objective:To evaluate the anticancer activity of vanillin semicarbazone(VSC) against Ehrlich ascites carcinoma(EAC) cells in Swiss albino mice.Methods:The compound VSC at three doses(5, 7.5 and 10 mg/kg i.p.) was admi...Objective:To evaluate the anticancer activity of vanillin semicarbazone(VSC) against Ehrlich ascites carcinoma(EAC) cells in Swiss albino mice.Methods:The compound VSC at three doses(5, 7.5 and 10 mg/kg i.p.) was administered into the intraperitoneal cavity of the EAC inoculated mice to observe its efficiency by studying the cell growth inhibition, reduction of tumour weight,enhancement of survival time as well as the changes in depleted hematological parameters. Allsuch parameters were also studied with a known standard drug bleomycin at the dose of 0.3 mg/kg(i.p.).Results:Among the doses studied, 10 mg/kg(i.p.) was found to be quite comparable in potency to that of bleomycin at the dose of 0.3 mg/kg(i.p.). The host toxic effects of VSC was found to be negligible.Conclusions:It can be concluded that VSC can therefore be considered as potent anticancer agent.展开更多
基金the financial support by the National Natural Science Foundation of China (42042050, U2005207)Natural Science Foundation of Fujian Province, China (2020J0141)。
文摘In this study, concentrations of Cr, Mn, Ni, Cu, Zn, Cd and Pb were determined in road dusts collected from different locations in Dhaka to assess source, contamination status and health risk. Energy-dispersive X-ray fluorescence spectroscopy and energy-dispersive X-ray spectroscopy were used to determine Cr, Mn, Ni, Cu, Zn, Cd and Pb and their mean concentrations were 162.27 ± 29.46, 721.18 ± 180.14, 35.65 ± 12.55, 104.56 ± 128.33, 515.32 ± 321.90,BDL, and 342.82 ± 591.20 mg/kg, respectively. Among the heavy metals, highest concentrations of Cu, Zn and Pb were found at urban sites-7(municipal waste dumping) and 8(medical waste incineration). Highest concentration of Cr followed by Cu and Zn was found at site-5(Tejgaon, urban). Principal component analysis revealed that anthropogenic activities are the potential sources for Cr, Ni, Cu, Zn and Pb while earth crust for Mn. Pollution index and pollution load index results suggested that all the sites were contaminated and/or degraded by Cr, Cu, Zn and Pb except sites-9(urban), 10(sub-urban), 11(rural) while sites-7 and 8(urban) were extremely degraded. For noncarcinogenic health risk, hazard quotient values for dermal were higher compared to that of inhalation/ingestion. Though hazard index values were less than 1 at all the sites, these were at least one order of magnitude higher for children group than that of adult group, thus the children group may face more noncarcinogenic health risk at sites -7 and 8. Values of incremental lifetime cancer risk were from 10to 10showed no carcinogenic health risk by road dusts contaminated with the heavy metals.
基金The US Department of State for sponsoring undergraduate exchange program。
文摘Ocean productivity is the foundation of marine food web,which continuously removes atmospheric carbon dioxide and supports life at sea and on land.Spatio-temporal variability of net primary productivity(NPP),sea surface temperature(SST),sea surface salinity(SSS),mixed layer depth(MLD),and euphotic zone depth(EZD) in the northern B ay of Bengal(BoB) during three monsoon seasons were examined in this study based on remote sensing data for the period 2005 to 2020.To compare the NPP distribution between the coastal zones and open BoB,the study area was divided into five zones(Z1-Z5).Results suggest that most productive zones Z2 and Zl are located at the head bay area and are directly influenced by freshwater discharge together with riverine sediment and nutrient loads.Across Z1-Z5,the NPP ranges from 5 315.38 mg/(m^(2)·d) to 346.7 mg/(m^(2)·d)(carbon,since then the same).The highest monthly average NPP of 5 315.38 mg/(m^(2)·d) in February and 5 039.36 mg/(m^(2)·d) in June were observed from Z2,while the lowest monthly average of 346.72 mg/(m^(2)·d) was observed in March from Z4,which is an oceanic zone.EZD values vary from 6-154 m for the study area,and it has an inverse correlation with NPP concentration.EZD is deeper during the summer season and shallower during the wintertime,with a corresponding increase in productivity.Throughout the year,monthly SST shows slight fluctuation for the entire study area,and statistical analysis shows a significant correlation among NPP,and EZD,overall positive between NPP and MLD,whereas no significant correlation among SSS,and SST for the northern BoB.Long-term trends in SST and productivity were significantly po sitive in head bay zones but negatively productive in the open ocean.The findings in this study on the distribution of NPP,SST,SSS,MLD,and EZD and their seasonal variability in five different zones of BoB can be used to further improve the management of marine resources and overall environmental condition in response to climate changes in BoB as they are of utmost re
文摘In this research, we have projected and carried out a novel fishbone network that shows better performance in the term of minimizing the packet delay with respect to sink speed. Previous study implies that sector angle affects greatly on designing fishbone network. Finite Set of nodes arranges to sense the physical condition of any system is called wireless sensor. Our designed fishbone network can be potentially applied for a wireless sensing system to formulate a whole network. The network is a novel design which has been finalized by comparing sector angle. Analysis takes place by varying packet delay according to sink speed. Future analysis takes place for Quality of Service (QoS) and Quality of Experience (QoE). Latency of Packet and its size is the measurement criteria of any network or service is called Quality of Service (QoS). On the other hand the user experience of using the designed network is called Quality of Experience (QoE). Our designed network has been analyzed in TCP Tracer to find out the latency or packet delay for different users. The user data has been shorted and equated among them for latency with different no of packets. Our proposed spiral fishbone network shows better QoS and QoE. In future more nodes can be added to design extended fishbone network for wireless.
文摘Ethernet network, standardized by IEEE 802.3, is vastly installed in Local Area Network (LAN) for cheaper cost and reliability. With the emergence of cost effective and enhanced user experience needs, the Quality of Service (QoS) of the underlying Ethernet network has become a major issue. A network must provide predictable, reliable and guaranteed services. The required QoS on the network is achieved through managing the end-to-end delay, throughput, jitter, transmission rate and many other network performance parameters. The paper investigates QoS parameters based on packet size to analyze the network performance. Segmentation in packet size larger than 1500 bytes, Maximum Transmission Unit (MTU) of Ethernet, is used to divide the large data into small packets. A simulation process under Riverbed modeler 17.5 initiates several scenarios of the Ethernet network to depict the QoS metrics in the Ethernet topology. For analyzing the result from the simulation process, varying sized packets are considered. Hence, the network performance results in distinct throughput, end-to-end delay, packet loss ratio, bit error rate etc. for varying packet sizes.
基金MoES (Govt of India)for his financial assistance to our project (GPP364).
文摘The Cenozoic-age Makum coal from northeastern India offers numerous research opportunities because of its diverse geochemical and geological characteristics.Due to its high sulfur content,the coal has been found to be less useful for industrial purposes.It can,however,serve as a hub for ongoing research on coal-based derivative products.The aim of this research work is to investigate the mineralogical and geochemical compositions of the coal,mine overburden(MOB)and shale samples taken from the Makum coal field and also on establishing a mutual relationship between them.To characterize the geochemical controlling factors of the Makum coal field,the study employs coal petrography,FTIR,mineralogical,and geochemical analysis.According to X-ray diffraction analysis,the major minerals like quartz,kaolinite,haematite,illite,pyrite,and calcite are present in coal and MOB.Pyrite is observed by SEM-EDS analysis as cubic-shaped particles that are smaller than a fewμm in size.The presence of sulfide minerals represents a phase of pyrite mineralization.The petrography study was used to better understand the environment that existed during the formation of the plant material,which aids us in determining the quantity of detrital mineral sediment contained in the coal.According to the ICP-MS analysis,the samples indicate significant levels of rare earth elements including yttrium.The present study reveals higher concentrations of poten-tial hazardous elements in the coal samples,with V,Cr,Ni,Cu,and Zn content in coal being considerably enriched compared to world-average concentrations.The correlation analysis reveals that the potential hazardous elements like Co,Ni,As,and Cu are associated with pyrite as they have strong affinity towards pyrite.Thus,numerous minerals and rare earth elements(REEs)exist,opening up a fresh avenue for more research in the area.This study also assists researchers in understanding the significance of Makum coal and provides numerous ideas for coal characterization.
文摘From the environmental consideration,it would be very interesting to use natural fibers such as banana,jute or coir as reinforcement materials instead of artificial fibers or any kind of synthetic materials.Natural fibers have many advantages over synthetic ones.Polypropylene banana fiber composites(PPBC)are prepared using untreated and alkali-treated banana fibers at 10-25%by weight of the fiber loading.The thermal properties of polypropylene natural fiber composites are very important for technological uses.Thermogravimetric measurements show that the incorporation of banana fiber into PP enhances the thermal stability of composites containing treated fibers,in comparison with untreated fibers.A composite of biodegradable polypropylene(PP)reinforced with short banana natural fibers was prepared by melt blending followed by a hot press molding system.The thermal properties of matrix materials were studied using thermogravimetric analyzers TGA units.It is observed that the introduction of short banana fibers slightly improved the thermo oxidative stability of PP-banana composites.Physical and chemical changes occurred through dehydration,phase transition,molecular orientation,crystallinity disruption,oxidation and decomposition,and incorporation of several functional groups.Systematic investigations of the thermal behavior of polymers in gas,vacuum or inert atmosphere give the knowledge of how change takes place in polymers.To understand such changes thermogravimetric analysis(TGA)and thermal analysis(TG)were performed.It is observed reinforcement of short banana fiber leads to little improvement in the thermooxidative stability of PPBC.Due to the enhancement of thermo-mechanical properties,such composites may be used as building materials namely roof materials,selling materials and many other engineering applications.
文摘In this research, the denoising of speckled SAR image has been done with fuzzy filters (ATMED, TMED, ATMAV & TMAV). SAR image or Synthetic Aperture Radar image consists of the informatics of ISW (Internal solitary waves). A new technique has been proposed which preserved the edge pixels by fuzzy edge detection method and then altered with the filtered image-pixels by fuzzy filtration for getting the denoised image. The comparative result shows that the proposed filter performs better than the other filtered results in terms of PSNR (41.61 dB), MAE (1.47), MSE (4.54) for TMAVxAPE & SSIM (81%) for ATMEDwAPE. The proposed method in this research shows better SSI (Spackle Suppression Index) value. Therefore the experimental result illustrates that the suggested fuzzy filter is much more capable of simultaneously protecting edges and suppressing speckle noise. This research will be beneficial to remove spackle noise from SAR images and can be used for remote sensing and mapping of surface area of earth.
文摘The standard specification of IEEE 802.15.4 is called ZigBee Propocol. ZigBee protocol required security, low data transfer rate, power efficient network. In addition, the ZigBee mobility function makes the ZigBee network more interactive and multi-purpose. The ZigBee mobile node has a significant effect on network parameters, namely MAC delay, end-to-end delay, MAC throughput and network load. However, a particular significant ZigBee node affects network data traffic and reduces the strength of the Quality of Service (QoS). The key issues are to analyze the QoS in order to increase overall performance of the network. The study proposes a ZigBee network with the mobile node and fixed node based on a variety of MAC layer settings. The Riverbed Network Simulator (Academic Modeler Release 17.5) is used for configuring and simulating the ZigBee network in a variety of conditions. The simulation results show that ZigBee with a fixed node performs better than the ZigBee mobile node. The ZigBee network with fixed node produces a lower network load and a high ratio of successfully transmitted data. The analysis of this study allows the ZigBee network to be better designed.
文摘Wireless Sensor Network (WSN) is a special type of communication medium through distributed sensor nodes. Popular wireless sensor nodes like ZigBee have splendid interoperability after IEEE 802.15.4 standardization in the domain of wireless personal area network (WPAN). ZigBee has another great feature mobility that makes the ZigBee network more versatile. The mobility feature of ZigBee mobile nodes has a greater impact on network performance than fixed nodes. This impact sometimes turns into more severe because of network structure and mobility model. This study mainly focuses on the performance analysis of the ZigBee mobile node under Random and Octagonal mobility management model with the Tree routing method. The Riverbed academic modeler is used to design, implement and simulate the ZigBee network under certain conditions. This study also presents a competitive performance analysis based on ZigBee mobile nodes transmitter and receiver characteristics under the observation of the mobility model. This indicates that Octagonal mobility model exhibits better performance than the Random mobility model. This study will constitute a new way for further designing and planning a reliable and efficient ZigBee network.
文摘There are reports on the use of chemicals like sodium tri polyphosphate (STPP) and foreign materials like pearl tapioca (locally called ‘sagu’), jelly (litchi) to adulterate freshwater prawn (Macrobrachium rosenbergii) prior to freeze processing to increase their weight. Studies were, therefore, undertaken to determine the changes in product quality on the use of different concentrations of STPP, sagu and litchi under ice storage condition. Percent weight gain of prawn was 5.46, 18.87 and 23.50 when dipped in 2%, 4% and 6% STPP solution, respectively. In all cases maximum water uptake by prawn muscle was during the first 6 h with fastest weight gain with STPP solutions containing tap water compared to those of ice and tap water. Organoleptic quality of the STPP treated samples became brown and spongy after 8 h of dipping treatment under iced condition. Quality assessment studies conducted after injecting sagu and litchi in prawn muscle showed little or no difference with those of control samples during the first 6 h, which turned whitish and swollen with severe drip loss after 24 h of ice stored condition, indicating characteristics for easy identification of the injected shrimps by organoleptic method.
文摘Background: CT-scan is a very useful diagnostic tool for the detection of hepatic mass. Objective: The present study was undertaken to determine the CT-scan findings of benign and malignant hepatic mass patients. Methodology: This was a cross sectional study conducted in Radiology and Imaging Department at Mymensingh Medical College Hospital (MMCH), Mymensingh;Dhaka Medical College Hospital (DMCH), Dhaka and Banghabandhu Sheikh Mujib Medical University (BSMMU), Dhaka with the collaboration of Pathology Department of the same institute for histopathological confirmation. This study was carried out from January 2006 to December 2007 for a period of 2 years. The patients who were clinically suspected of having hepatic mass attended in the Radiology and Imaging Department in the above mentioned institutes were included as study population. All the CT-scan findings were recorded. Result: A total number of 50 patients were enrolled for this study. CT-scan was done among 40 males and 10 females with a mean age of 51.28 years old. Hypodensity was found in 17 (60.7%) and 18 (81.8%) cases in malignant and benign hepatic lesions respectively. Ill-defined margin was detected in 12 (42.9%) and 6 (27.3%) cases respectively. Calcification was present on 11 (39.3%) malignant lesion and 6 (27.3%) benign lesions. Pressure effect on biliary apparatus was found in 11 (39.3%) malignant lesions and 1 (4.5%) benign lesions (p < 0.05). Lymphadenopathy was found in 10 (35.7%) malignant lesions and 1 (4.5%) benign lesions (p < 0.05). Conclusion: In conclusion, CT-scan findings of malignant and benign hepatic mass show hypodensity with more contrast enhancement in malignant lesions with more calcification in malignant lesion;however, significant difference is detected in pressure effect on biliary apparatus and lymphadenopathy.
文摘The main purpose of this study is to find the awareness level as well as the determinants of awareness on HIV/AIDS among the garments workers in Dhaka City, Bangladesh. To do so, 200 garments workers were interviewed through a structured questionnaire using purposive sampling technique. As the statistical tools, univariate analysis was completed to figure out frequency distribution and the binary logistic regression model was used to predict the probability occurrence of the events by fitting data. The results revealed that the majority of the garments workers (63.5%) are very young (18 - 27 years), almost all (97.5%) are literate and most of them (57.0%) used contraceptives. Importantly, most of the respondents (64.0%) had not participated in any type of seminar or workshop related to HIV/AIDS, though almost all the respondents (84.5%) know HIV is a dangerous and life threatening disease. The logistic regression model identified that respondents' education, contraceptive usage, mass media and HIV workshops have statistically significant positive effects on HIV/AIDS awareness. Various media campaigns are strongly suggested to be increased knowledge and awareness to control the spread of HIV as well as STDs among garments workers in Bangladesh.
文摘Cryptography is the study that provides security service. It concerns with confidentiality, integrity, and authentication. Public key cryptography provides an enormous revolution in the field of the cryptosystem. It uses two different keys where keys are related in such a way that, the public key can use to encrypt the message and private key can be used to decrypt the message. This paper proposed an enhanced and modified approach of RSA cryptosystem based on “n” distinct prime number. This existence of “n” prime number increases the difficulty of the factoring of the variable “N” which increases the complexity of the algorithm. In this approach, two different public key and private key generated from the large factor of the variable “N” and perform a double encryption-decryption operation which affords more security. Experiment on a set of a random number provided that the key generation time, analysis of variable “N”, encryption and decryption will take a long time compared to traditional RSA. Thus, this approach is more efficient, highly secured and not easily breakable.
文摘The HIV/AIDS epidemic has grown on an unprecedented scale since it was first recognized, and presently it is considered as a well known global public health crisis. In making the health policy where millions of populations are at risk, it is necessary to understand the knowledge level about HIV/AIDS. So, this study aimed at to investigate the knowledge level about HIV/AIDS among the villagers. Data and necessary information were collected from one hundred villagers of Salmanpur from Comilla district, Bangladesh through a structured questionnaire. The collected data were used for univariate analysis, to carry out the description of the variables;and to justify the total score of knowledge about HIV/AIDS among the respondents, Cronbach’s alpha (α) was calculated. The results revealed that almost all the respondents (92.00%) were ever heard about HIV/AIDS and half of them (51.00%) were known it as a communicable disease. Majority of the respondents (62.00%) believed that it is caused by heterosexual relation as well as sex with HIV positive persons. However, a good number of respondents were found unaware about the major causes and preventive ways of AIDS. Less than half of the respondents (45.00%) had medium knowledge (α = 0.34 - 0.66) and only 36.00% had the enough knowledge about HIV/AIDS. The knowledge level is increasing with the increase of education level, and the respondents who involved in agricultural works are found the lowest knowledge level (47.00%) about HIV/AIDS. The villagers were known about HIV/AIDS but they do not have accurate information about the ways in which AIDS virus can or cannot be transmitted. Therefore, effective programs should be taken to increase the knowledge level about HIV/AIDS among the villagers in Bangladesh.
文摘The Wireless Sensor Network (WSN) is spatially distributed autonomous sensor to sense special task. WSN like ZigBee network forms simple interconnecting, low power, and low processing capability wireless devices. The ZigBee devices facilitate numerous applications such as pervasive computing, security monitoring and control. ZigBee end devices collect sensing data and send them to ZigBee Coordinator. The Coordinator processes end device requests. The effect of a large number of random unsynchronized requests may degrade the overall network performance. An effective technique is particularly needed for synchronizing available node’s request processing to design a reliable ZigBee network. In this paper, region based priority mechanism is implemented to synchronize request with Tree Routing Method. Riverbed is used to simulate and analyze overall ZigBee network performance. The results show that the performance of the overall priority based ZigBee network model is better than without a priority based model. This research paves the way for further designing and modeling a large scale ZigBee network.
文摘China has departed from the East Asian development model by letting inequality rise to a high level, which is now contributing to China＇s current problems of macroeconomic imbalance, declining efficiency of capital, and rising social tensions. If inequality persists, China may get caught in the ＂inequality-trap,＂ which may then lead to the middle income trap （MIT）. Fortunately, China still has the levers to pull to reduce inequality and avoid the MIT. Measures along both the ＂wage route＂ and the ＂redistributive route＂ can be adopted for this purpose. In addition, China may pursue the ＂cooperative route＂ to more equitable distribution.
基金the Head of the Civil Engineering Department,Faculty of Engineering and Technology,Jamia Millia Islamia,New Delhi-110025,India.
文摘This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pipe(CFUT)with different geometric properties were tested.To obtain the specimens different class pipes with three different diameters were used to investigate the sensitivity of these columns to various parameters.The effect of each variable on the ultimate strength,ductility and confinement efficiency of the samples was investigated.All specimens were compressed by applying load only to the concrete core to obtain the load-displacement variations and the corresponding deformation mode.A finite element model was developed using the proposed stress-strain variation of confined concrete with UPVC tubes to simulate axial compression of CFUT specimens.According to the results obtained,the effect of the change in diameter-thickness ratio failure stress of concrete limited by(D/t)is obtained and discussed with empirical relationship.Polypropylene fibers were found to slightly increase column strength up to a certain volume fraction,after which the strength generally experienced a decrease.
基金financially supported by University Grants Commission of Bangladesh[grant No.6(76)/UGC/BK/Chemistry(9)/2007-2008/3268]
文摘Objective:To evaluate the anticancer activity of vanillin semicarbazone(VSC) against Ehrlich ascites carcinoma(EAC) cells in Swiss albino mice.Methods:The compound VSC at three doses(5, 7.5 and 10 mg/kg i.p.) was administered into the intraperitoneal cavity of the EAC inoculated mice to observe its efficiency by studying the cell growth inhibition, reduction of tumour weight,enhancement of survival time as well as the changes in depleted hematological parameters. Allsuch parameters were also studied with a known standard drug bleomycin at the dose of 0.3 mg/kg(i.p.).Results:Among the doses studied, 10 mg/kg(i.p.) was found to be quite comparable in potency to that of bleomycin at the dose of 0.3 mg/kg(i.p.). The host toxic effects of VSC was found to be negligible.Conclusions:It can be concluded that VSC can therefore be considered as potent anticancer agent.
