Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the ...Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the Kutubpalong & Balukhali Rohingya camp area. An attempt has been made to see the influence of seasonal variation of ground water level (G.W.L.) fluctuations on the stability of the eco hills and forests of Ukhiya Teknaf region. Ukhiya hills are in great danger because of cutting trees from the hill slopes and it is well established that due to recent change of climate, short term rainfall for few consecutive days during monsoon might show an influence on the factor of safety (Fs) values of the camp hill slopes. A clear G.W.L. variation between dry and wet seasons has an influence on the stability (Fs) values indicating that climate has a strong influence on the stability and threatening sustainable development. A stable or marginally stable slope might be unstable during raining and show a variation of ground water level (G.W.L.). The generation of pore water pressure (P.W.P.) is also influenced by seasonal variation of ground water level. During wet season negative P.W.P. called suction plays an important role to occur slope failures in the Ukhiya hills. Based on all calculated factor of safety values (Fs) at different locations, four (4) susceptible landslide risk zones are identified. They are very high risk (Fs = 0.18 to 0.46), high risk (Fs = 0.56 to 0.75), medium risk (Fs = 0.76 to 1.0) and marginally stable areas (Fs ≈ 1). Proper geo-engineering measures must be taken by the concerned authorizes to reduce P.W.P. during monsoon by installing rain water harvesting system, allowing sufficient drainage & other geotechnical measures to reduce the risk of slope failures in the Ukhiya hills. Based on the stability factor (Fs) at different slope locations of the camp hills, a risk map of the investigated area has been produced for the local community for their safety and to build up awareness & to m展开更多
Area studied in this paper is located in the northwest of city of Alasht. The most important varieties of studied rocks are volcanic and semi-volcanic rocks of basic nature. These rocks, which form a distinguishable s...Area studied in this paper is located in the northwest of city of Alasht. The most important varieties of studied rocks are volcanic and semi-volcanic rocks of basic nature. These rocks, which form a distinguishable solid mass on 1:100,000 geological map, belong to Cretaceous period. According to results of petrographic study, rocks of this area include olivine basalt, dolerite, gabbro and microgabbro, and all have almost similar chemical compositions. According to chemistry-based naming process carried out through TAS method, these rocks are entirely basalt and basic and are all products of Sub-alkaline-Tholeiitic magma. According to Harker diagrams, a magmatic differentiation can be observed in all volcanic rocks;furthermore, basaltic magma erupted in this area has undergone an alteration and possibly a crustal contamination. The spider diagrams plotted in this paper show that basic rocks of Alasht area (basalts, andesite basalts, dolerites, gabbros and microgabbros) are all mostly similar to ocean island basalts (OIB). Once field study, sampling and microscopic study stages were complete, ten samples were selected for chemical analysis and were analyzed by XRF method.展开更多
This paper systematically investigates the effective parameter ontheperformanceof polydimethylsiloxane/graphene(PDMS@Gr)-based triboelectric nanogenerators(TENGs)as well as their applications.PDMS@Gr films containing ...This paper systematically investigates the effective parameter ontheperformanceof polydimethylsiloxane/graphene(PDMS@Gr)-based triboelectric nanogenerators(TENGs)as well as their applications.PDMS@Gr films containing 0,0.05,0.5,1,and 1.5 wt.%graphene are synthesized,and their sur-face characteristics,mechanical behavior,and electrical prop-erties are characterized.Vertical contact-separation mode TENGs are fabricated,and their performance is evaluated.The results demonstrate that the surface roughness and sur-face charge density are the most critical parameters for the performance of PDMS@Gr-based TENGs compared to the elec-trical and mechanical properties of the friction layers.The PDMS@Gr-based TENG with 1 wt.%graphene shows the high-est power output of 2.6 W/m?at an optimized working con-dition(5 Hz and 15 N).It also exhibits stable power output until 15,oo0 working cycles and displays battery-free applica-tions by powering a light-emitting diode(LED)array,a calculator,a digital watch,and a digital thermometer.展开更多
The role of double oxide film （bifilm） defects in the formation of gas porosity in commercial purity and Srcontaining AI alloys was investigated by means of a reduced pressure test （RPT） technique. The liquid meta...The role of double oxide film （bifilm） defects in the formation of gas porosity in commercial purity and Srcontaining AI alloys was investigated by means of a reduced pressure test （RPT） technique. The liquid metal was poured from a height into a crucible to introduce oxide defects into the melt. The melt was then subjected to different ＂hydrogen addition＂ and ＂holding in liquid state＂ regimes before RPT samples were taken. The RPT samples were then characterized by determining their porosity parameters and examining the internal surfaces of the pores formed in them by scanning electron microscopy. The results indicated oxide defects as the initiation sites for the growth of gas porosity, both in commercial purity and Sr-containing AI alloys. The results also rejected reduction of the surface tension of the melt, increase in the volumetric shrinkage and reduction in interdendritic feeding as the possible causes of an increase in the porosity content of the AI castings modified with strontium. The change in the composition of the oxide layers of double oxide film defects was suggested to be responsible for this behaviour.展开更多
Dikes can be divided into sheeted, feeder, cone and swarm types based on the origin and the formation. A group of dikes that are formed in dense in a relatively broad zone influenced by a particular tectonic regime ar...Dikes can be divided into sheeted, feeder, cone and swarm types based on the origin and the formation. A group of dikes that are formed in dense in a relatively broad zone influenced by a particular tectonic regime are referred to as swarm dikes. Swarm dikes have numerous applications such as locating mantle plume centers, determining areas of longstanding tensions and detection of deformation networks. The purpose of this article is classified swarm dikes of “North of Saveh” based on previous studies. In one study, swarm dikes are classified based on their initial geometry into five types of I, II, III, IV and V. According to this classification, our study has been shown that the dikes in north of Saveh are of type IV. In another study, the swarm dikes are classified into three types: parallel, large radial and small radial. According to the classification, our study has been shown that the dikes of North Saveh are parallel that have arisen by tensions caused by the collision of the Arabian plate and the Central Iran plate. In addition to original tensions in the region, local faults have been effective on the arrangement and the establishment of dikes.展开更多
The present study characterized NbSi2-Al2O3 nanocomposite powders plasma-sprayed on Ti-6Al-4Vsubstrates. The powders were agglomerated to obtain suitable particle sizes for spraying. The agglomerated powders were then...The present study characterized NbSi2-Al2O3 nanocomposite powders plasma-sprayed on Ti-6Al-4Vsubstrates. The powders were agglomerated to obtain suitable particle sizes for spraying. The agglomerated powders were then plasma-sprayed using atmospheric plasma spraying. The structural transformations of the powders along with the morphological and mechanical changes of the coatings were examined by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and hard- ness testing. The results showed that after plasma spraying, the grain size increased, and the lattice strain decreased. However, the grain size of this compound after spraying was still in the nanometer range. The coating was uniform and exhibited good adhesion to the substrate. The microhardness and fracture toughness of the nanocomposite coating were higher than those of a nanostructured NbSi2 coating.展开更多
We report a 43-year-old man who presented with a right painful shoulder mass and bilateral lung masses in computed tomography(CT).Scapular mass was excised and pathology report demonstrated high-grade metastatic tumor...We report a 43-year-old man who presented with a right painful shoulder mass and bilateral lung masses in computed tomography(CT).Scapular mass was excised and pathology report demonstrated high-grade metastatic tumor.Same side lung biopsy and histopathological study characterized tuberculosis but biopsy of the left lung lesion identified adenocarcinoma of the lung.The final diagnosis was right scapular metastatic lesion from left lung adenocarcinoma.Musculoskeletal symptoms are commonly encountered in lung malignancies due to paraneoplastic syndrome or hematogenous metastasis but scapular metastasis on the other side as the presentation of lung cancer is extremely rare.展开更多
KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s des...KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s design and environment. In this study, the Finite Element Model of the KK-type tubular joint has been created, and analysis has been performed under static loading using the Static Structural analysis system of ANSYS 19.2 commercial software and structural mechanics module of COMSOL Multiphysics. The KK tubular model is analyzed under compressive load conditions, and the resulting stress, strain, and deformation values are tabulated in both graphical and tabular form. This study includes a comparison of the outcomes from both commercial software. The results highlight that maximum stress, strain, and deformation values decrease as joint thickness increases. This study holds significant relevance in advancing the understanding of tubular KK joints and their response to compressive loading. The insights derived from the analysis have the potential to contribute to the development of more robust and reliable tubular KK joints in various engineering and structural applications. .展开更多
Background: Cholecystectomy is one of the most now common abdominal surgeries performed every day. The incidence of bile duct injury (BDI) following open cholecystectomy is only 0.1% - 0.2%. After the introduction of ...Background: Cholecystectomy is one of the most now common abdominal surgeries performed every day. The incidence of bile duct injury (BDI) following open cholecystectomy is only 0.1% - 0.2%. After the introduction of laparoscopic cholecystectomy, the incidence has gone up to 0.4% - 0.7%. The present study is a prospective analysis of all patients with bile duct injury who were admitted to Dhaka Medical College Hospital during or at a variable period following cholecystectomy. Methods: To determine the pattern of presentation of iatrogenic biliary injury following cholecystectomy in the department of surgery of Dhaka Medical College Hospital, a total of 30 patients were purposively selected from May 2018 to November 2018. Patient particulars, records of physical and clinical evaluation, and operative details were collected by individual researchers. Data analysis was done by SPSS for windows version 21. Results: BDI was found very common among the age group 21 - 30 yrs (36%) and female dominant (60%). Majority of the patients presented with abdominal pain (96%), intra-abdominal collection (88%), biliary peritonitis (68%), cholangitis (60%), and obstructive jaundice (40%), and biliary fistula (40%). Laparoscopic cholecystectomy (84%) was the principal cause of biliary injury in our study. 48% of patients experienced clinical features within 7 days post-cholecystectomy. Per-operative diagnosis was done in only 12% of cases. 44% of patients in this study were recognized as Bismuth grade-3, followed by 36%, grade-2 patients. Management outcomes included wound infection (41.66%), minor bile leak (25%), peritonitis (8.33%), and renal impairment (8.33%). Conclusion: The effect of BDI is an extremely distressful clinical condition for the patients and their family members, hence proper care and management protocol should be followed.展开更多
The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of t...The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.展开更多
Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation re...Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation represents the satisfaction or the dissatisfaction of relationship, connection or correspondence between the objects of two or more sets. However, there are some problems that can’t be solved through classical relationships, such as the relationship between two objects being vague. In those situations, picture fuzzy relation over picture fuzzy sets is an important and powerful concept which is suitable for describing correspondences between two vague objects. It represents the strength of association of the elements of picture fuzzy sets. It plays an important role in picture fuzzy modeling, inference and control system and also has important applications in relational databases, approximate reasoning, preference modeling, medical diagnosis, etc. In this article, we define picture fuzzy relations over picture fuzzy sets, including some other fundamental definitions with illustrations. The max-min and min-max compositions of picture fuzzy relations are defined in the light of picture fuzzy sets and discussed some properties related to them. The reflexivity, symmetry and transitivity of a picture fuzzy relation are described over a picture fuzzy set. Finally, various properties are explored related to the picture fuzzy relations over a picture fuzzy set.展开更多
In this article, we define the arithmetic operations of generalized trapezoidal picture fuzzy numbers by vertex method which is assembled on a combination of the (α, γ, β)-cut concept and standard interval analysis...In this article, we define the arithmetic operations of generalized trapezoidal picture fuzzy numbers by vertex method which is assembled on a combination of the (α, γ, β)-cut concept and standard interval analysis. Various related properties are explored. Finally, some computations of picture fuzzy functions over generalized picture fuzzy variables are illustrated by using our proposed technique.展开更多
Ecosystem maps are vital to represent ecological patterns and processes in a region. It enables the use of ecosystem goods and services as a robust unit for a variety of applications, including conservation planning, ...Ecosystem maps are vital to represent ecological patterns and processes in a region. It enables the use of ecosystem goods and services as a robust unit for a variety of applications, including conservation planning, climate change adaptation and mitigation measures, resource management, and the economic estimation of ecosystem benefits. As different elements of eco-geological components, such as the geological, soil, and biotic assemblages organize an ecosystem;here, we developed an ecosystem map of the State of Selangor, Peninsular Malaysia, using geology, soil, elevation, and land-use data. Landsat ETM+ images, ASTER Digital Elevation Model (DEM) data, and digitized soil and geological data were integrated to develop a map of the types of ecosystem for 2005. We found 19 different natural ecosystems in the studied region that represented approximately 35% of the total land area. Among the natural ecosystems, peat-swamp forest represents highest (at ~10%), while montane ericaceous forest representing the lowest (at ~0.008%) and the hill dipterocarp quartz forest, lowland dipterocarp sandstone forest, upper dipterocarp quartz forest, and mangrove forest are representing approximately 6.4%, 4.6%, 3% and 2.6% of the total land area respectively. These data can be used to prioritize the areas deserving attention due to their value for biodiversity conservation and for the production of goods and supply of ecosystem services. In addition to a variety of ecological and environmental aspects, such an ecosystem map has potential use for the sustainable management of natural resources at the national, regional, continental, and global scales.展开更多
<strong><em>Background</em></strong><span style="font-family:Verdana;"><strong>:</strong></span><span style="font-family:;" "="">...<strong><em>Background</em></strong><span style="font-family:Verdana;"><strong>:</strong></span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Despite of different adverse events, streptokinase (SK) is widely used to treat patients presented with acute ST segment elevation myocardial infarction. </span><b><i><span style="font-family:Verdana;">Objective</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> The purpose of the present study was to observe different adverse events in patients of acute ST segment elevation myocardial infarction receiving SK infusion. </span><b><i><span style="font-family:Verdana;">Methodology</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> This cross-sectional type of analytic observational study was carried out in the inpatient department of Cardiology at National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from December 23</span><sup><span style="font-size:12px;font-family:Verdana;">rd</span></sup></span><span style="font-family:Verdana;"> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">2019 to February 22</span><sup><span style="font-size:12px;font-family:Verdana;">nd</span></sup><span style="font-family:Verdana;"> 2020 for a period of two (2) months. All patients diagnosed as acute ST segment elevation myocardial infarction receiving SK were included in the present study. Adverse events were documented through completing a questionnaire by reviewing the records in the medical file as well as interviewing with the patients. </span><b><i><span style="font-family:Verdana;">Result</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In this study, 43 (26.2%) patients developed different types of adverse events and 121 (73.8%) had no complications following SK infusion. The most common adverse event was hypotension </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verda展开更多
The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity g...The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity gain. The development of an analytical mathematical model of ensuring security in multicasting through fading channels incorporating this benefit of multi-hop relaying is still an open problem. Motivated by this issue, this paper considers a secure wireless multicasting scenario employing multi-hop relaying technique over frequency selective Nakagami-m fading channel and develops an analytical mathematical model to ensure the security against multiple eavesdroppers. This mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to ensure the security in the presence of multiple eavesdroppers. Moreover, the effects of the fading parameter of multicast channel, the number of hops and eavesdropper are investigated. The results show that the security in multicasting through Nakagami-m fading channel with multi-hop relaying system is more sensitive to the number of hops and eavesdroppers. The fading of multicast channel helps to improve the secrecy multicast capacity and is not the enemy of security in multicasting.展开更多
The Ready-Made Garments (RMG) industry is a major contributor to the economy of Bangladesh, accounting for over 80% of the country’s total exports. In recent years, the industry has faced challenges due to changing g...The Ready-Made Garments (RMG) industry is a major contributor to the economy of Bangladesh, accounting for over 80% of the country’s total exports. In recent years, the industry has faced challenges due to changing global fashion trends and increasing competition from other manufacturing countries. One of the latest trends in the fashion industry is micro seasonal fashion, which has significant impacts on the RMG industry of Bangladesh. The purpose of this study is to examine the impact of micro seasonal fashion on the RMG industry of Bangladesh. It will examine the changes in buyer and consumer behavior and demand patterns, the implications for manufacturers and suppliers, and the strategies adopted by industry players to adapt to this trend. The emergence of micro seasonal fashion has disorderly the traditional seasonal cycle of the fashion industry. Consumers are no longer satisfied with the two-season model of spring/summer and fall/winter, but instead demand new styles and trends every few weeks. This trend has created opportunities for the RMG industry of Bangladesh to cater to the fast-changing demands of consumers. Micro Seasonal Fashion also poses significant challenges for the industry. Manufacturers and suppliers must be able to produce and deliver garments quickly and efficiently, while ensuring high quality and sustainability standards. This requires investments in technology, supply chain management, and training of workers. To address these challenges, industry players in Bangladesh have adopted several strategies, such as diversifying product offerings, investing in technology and innovation, and enhancing sustainability practices. These strategies have helped the industry to remain competitive and meet the demands of fast-changing consumer preferences. The industry must be able to adapt quickly to the changing demands of consumers and invest in technology and sustainability practices to remain competitive. With the right strategies and investments, the RMG industry of Bangladesh can control the展开更多
The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by th...The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel.展开更多
Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now...Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now a challenging issue. In most cases, pantropical and regional biomass models are used frequently to estimate biomass and carbon stock in trees, but these estimation</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> have some uncertainty compared to the species-specific allometric biomass model. </span><i><span style="font-family:Verdana;">Acacia</span></i><span> <i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Casuarina</span></i> <i><span style="font-family:Verdana;">equisetifolia</span></i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Melia</span></i><span style="font-family:Verdana;"> <i>azedarach</i> </span><span style="font-family:Verdana;">have been planted in different areas of Bangladesh considering the species-specific site requirements. While </span><i><span style="font-family:Verdana;">Barringtonia</span></i><span style="font-family:Verdana;"> <i>acutangula</i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Pongamia</span></i><span style="font-family:Verdana;"> <i>pinnata</i> </span><span style="font-family:Verdana;">are the dominant tree species of the freshwater swamp forest of Bangladesh. This study was aimed to develop species-specific allometric biomass models for estimating stem and above ground biomass (TAGB) of these species using the non-destructive method and to compare the efficiency of the derived biomass models with the frequently used regional and pantropical biomass models. Four Ln-based models with diameter at breast height (DBH) and 展开更多
<em>Xylocarpus mekongensis</em> Pierre is the important tree species of the Sundarbans. The present study was conducted to evaluate the effect of salinity on the survival and growth of <em>X. mekonge...<em>Xylocarpus mekongensis</em> Pierre is the important tree species of the Sundarbans. The present study was conducted to evaluate the effect of salinity on the survival and growth of <em>X. mekongensis</em> seedlings. The distributional patterns of nitrogen, phosphorus, potassium, sodium, and carbon in seedling parts were also examined in relation to salinity. Comparatively higher survival (95%) of seedlings was observed at non-saline to slightly saline conditions (0-5 PSU) and it was decreased to 78% at 35 PSU salinity. The relative growth rate (RGR) was higher at non-saline to slightly saline (0 to 5 PSU) conditions compared to higher salinity. Nutrients, sodium, and carbon concentration are found to vary significantly (p < 0.05) among the parts of seedlings. Comparatively (p < 0.05) highest concentration of nitrogen (20 to 34 mg/g), phosphorus (0.50 to 0.75 mg/g), potassium (9 to 27 mg/g) and sodium (7 to 36 mg/g) were found in leaves, while the highest concentration of carbon (42% to 45%) was detected in the stem. However, nitrogen, potassium, and carbon concentration in different parts of seedlings showed significant (p < 0.05) negative correlations with salinity levels. It can be concluded that <em>X. mekongensis</em> has the capacity to tolerate higher saline condition but they grow well in non-saline to less saline conditions.展开更多
Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-grou...Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-ground biomass, nutrients (N, P and K) and carbon stock in A. corniclatum. A total of 8 linear models (y = aX + b, , y = aLogX + b, Logy = aX + b, Logy = aLogX + b, y = alnX + b, Lny = aX + b and Lny = alnX + b) with 64 regression equations were tested to derive the allometric model for biomass of each plant part;and nutrients and carbon stock in total aboveground biomass. The best fit allometric models were selected by considering the values of R<sup>2</sup>, CV, R<sub>mse</sub>, MS<sub>error</sub>, S<sub>a</sub>, S<sub>b</sub>, F value, AICc and Furnival Index. The selected allometric models were Logbiomass = 0.76LogDBH<sup>2</sup> - 1.39;Biomass = 0.07DBH<sup>2</sup> - 0.49;Logbiomass = 1.04LogDBH<sup>2</sup> - 1.80;Logbiomass = 1.04LogDBH<sup>2</sup> - 0.99;= 0.48DBH - 0.13 for leaves, branches, bark, stem without bark and total above-ground biomass respectively. The selected allometric models for Nitrogen, Phosphorous, Potassium and Carbon stock in total above-ground biomass were = 0.67DBH + 0.11;= 0.94DBH + 0.08;= 1.06DBH - 0.18;= 0.33DBH - 0.09 respectively.展开更多
文摘Bangladesh is a south Asian Monsoonal Country and the recent precipitation pattern in the Cox’s Bazar area of Bangladesh is changing and increasing the number of monsoonal slope failures and landslide hazards in the Kutubpalong & Balukhali Rohingya camp area. An attempt has been made to see the influence of seasonal variation of ground water level (G.W.L.) fluctuations on the stability of the eco hills and forests of Ukhiya Teknaf region. Ukhiya hills are in great danger because of cutting trees from the hill slopes and it is well established that due to recent change of climate, short term rainfall for few consecutive days during monsoon might show an influence on the factor of safety (Fs) values of the camp hill slopes. A clear G.W.L. variation between dry and wet seasons has an influence on the stability (Fs) values indicating that climate has a strong influence on the stability and threatening sustainable development. A stable or marginally stable slope might be unstable during raining and show a variation of ground water level (G.W.L.). The generation of pore water pressure (P.W.P.) is also influenced by seasonal variation of ground water level. During wet season negative P.W.P. called suction plays an important role to occur slope failures in the Ukhiya hills. Based on all calculated factor of safety values (Fs) at different locations, four (4) susceptible landslide risk zones are identified. They are very high risk (Fs = 0.18 to 0.46), high risk (Fs = 0.56 to 0.75), medium risk (Fs = 0.76 to 1.0) and marginally stable areas (Fs ≈ 1). Proper geo-engineering measures must be taken by the concerned authorizes to reduce P.W.P. during monsoon by installing rain water harvesting system, allowing sufficient drainage & other geotechnical measures to reduce the risk of slope failures in the Ukhiya hills. Based on the stability factor (Fs) at different slope locations of the camp hills, a risk map of the investigated area has been produced for the local community for their safety and to build up awareness & to m
文摘Area studied in this paper is located in the northwest of city of Alasht. The most important varieties of studied rocks are volcanic and semi-volcanic rocks of basic nature. These rocks, which form a distinguishable solid mass on 1:100,000 geological map, belong to Cretaceous period. According to results of petrographic study, rocks of this area include olivine basalt, dolerite, gabbro and microgabbro, and all have almost similar chemical compositions. According to chemistry-based naming process carried out through TAS method, these rocks are entirely basalt and basic and are all products of Sub-alkaline-Tholeiitic magma. According to Harker diagrams, a magmatic differentiation can be observed in all volcanic rocks;furthermore, basaltic magma erupted in this area has undergone an alteration and possibly a crustal contamination. The spider diagrams plotted in this paper show that basic rocks of Alasht area (basalts, andesite basalts, dolerites, gabbros and microgabbros) are all mostly similar to ocean island basalts (OIB). Once field study, sampling and microscopic study stages were complete, ten samples were selected for chemical analysis and were analyzed by XRF method.
基金supported by the National Research Foundation of Korea under the Creative Research Initiatives Program (NRF-2015R1A3A2066301).
文摘This paper systematically investigates the effective parameter ontheperformanceof polydimethylsiloxane/graphene(PDMS@Gr)-based triboelectric nanogenerators(TENGs)as well as their applications.PDMS@Gr films containing 0,0.05,0.5,1,and 1.5 wt.%graphene are synthesized,and their sur-face characteristics,mechanical behavior,and electrical prop-erties are characterized.Vertical contact-separation mode TENGs are fabricated,and their performance is evaluated.The results demonstrate that the surface roughness and sur-face charge density are the most critical parameters for the performance of PDMS@Gr-based TENGs compared to the elec-trical and mechanical properties of the friction layers.The PDMS@Gr-based TENG with 1 wt.%graphene shows the high-est power output of 2.6 W/m?at an optimized working con-dition(5 Hz and 15 N).It also exhibits stable power output until 15,oo0 working cycles and displays battery-free applica-tions by powering a light-emitting diode(LED)array,a calculator,a digital watch,and a digital thermometer.
文摘The role of double oxide film （bifilm） defects in the formation of gas porosity in commercial purity and Srcontaining AI alloys was investigated by means of a reduced pressure test （RPT） technique. The liquid metal was poured from a height into a crucible to introduce oxide defects into the melt. The melt was then subjected to different ＂hydrogen addition＂ and ＂holding in liquid state＂ regimes before RPT samples were taken. The RPT samples were then characterized by determining their porosity parameters and examining the internal surfaces of the pores formed in them by scanning electron microscopy. The results indicated oxide defects as the initiation sites for the growth of gas porosity, both in commercial purity and Sr-containing AI alloys. The results also rejected reduction of the surface tension of the melt, increase in the volumetric shrinkage and reduction in interdendritic feeding as the possible causes of an increase in the porosity content of the AI castings modified with strontium. The change in the composition of the oxide layers of double oxide film defects was suggested to be responsible for this behaviour.
文摘Dikes can be divided into sheeted, feeder, cone and swarm types based on the origin and the formation. A group of dikes that are formed in dense in a relatively broad zone influenced by a particular tectonic regime are referred to as swarm dikes. Swarm dikes have numerous applications such as locating mantle plume centers, determining areas of longstanding tensions and detection of deformation networks. The purpose of this article is classified swarm dikes of “North of Saveh” based on previous studies. In one study, swarm dikes are classified based on their initial geometry into five types of I, II, III, IV and V. According to this classification, our study has been shown that the dikes in north of Saveh are of type IV. In another study, the swarm dikes are classified into three types: parallel, large radial and small radial. According to the classification, our study has been shown that the dikes of North Saveh are parallel that have arisen by tensions caused by the collision of the Arabian plate and the Central Iran plate. In addition to original tensions in the region, local faults have been effective on the arrangement and the establishment of dikes.
文摘The present study characterized NbSi2-Al2O3 nanocomposite powders plasma-sprayed on Ti-6Al-4Vsubstrates. The powders were agglomerated to obtain suitable particle sizes for spraying. The agglomerated powders were then plasma-sprayed using atmospheric plasma spraying. The structural transformations of the powders along with the morphological and mechanical changes of the coatings were examined by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and hard- ness testing. The results showed that after plasma spraying, the grain size increased, and the lattice strain decreased. However, the grain size of this compound after spraying was still in the nanometer range. The coating was uniform and exhibited good adhesion to the substrate. The microhardness and fracture toughness of the nanocomposite coating were higher than those of a nanostructured NbSi2 coating.
文摘We report a 43-year-old man who presented with a right painful shoulder mass and bilateral lung masses in computed tomography(CT).Scapular mass was excised and pathology report demonstrated high-grade metastatic tumor.Same side lung biopsy and histopathological study characterized tuberculosis but biopsy of the left lung lesion identified adenocarcinoma of the lung.The final diagnosis was right scapular metastatic lesion from left lung adenocarcinoma.Musculoskeletal symptoms are commonly encountered in lung malignancies due to paraneoplastic syndrome or hematogenous metastasis but scapular metastasis on the other side as the presentation of lung cancer is extremely rare.
文摘KK tubular joints are used to build jacket-type offshore structures. These joints are mostly made up of structural steel. These joints can withstand yield, buckling, and lateral loads depending on the structure’s design and environment. In this study, the Finite Element Model of the KK-type tubular joint has been created, and analysis has been performed under static loading using the Static Structural analysis system of ANSYS 19.2 commercial software and structural mechanics module of COMSOL Multiphysics. The KK tubular model is analyzed under compressive load conditions, and the resulting stress, strain, and deformation values are tabulated in both graphical and tabular form. This study includes a comparison of the outcomes from both commercial software. The results highlight that maximum stress, strain, and deformation values decrease as joint thickness increases. This study holds significant relevance in advancing the understanding of tubular KK joints and their response to compressive loading. The insights derived from the analysis have the potential to contribute to the development of more robust and reliable tubular KK joints in various engineering and structural applications. .
文摘Background: Cholecystectomy is one of the most now common abdominal surgeries performed every day. The incidence of bile duct injury (BDI) following open cholecystectomy is only 0.1% - 0.2%. After the introduction of laparoscopic cholecystectomy, the incidence has gone up to 0.4% - 0.7%. The present study is a prospective analysis of all patients with bile duct injury who were admitted to Dhaka Medical College Hospital during or at a variable period following cholecystectomy. Methods: To determine the pattern of presentation of iatrogenic biliary injury following cholecystectomy in the department of surgery of Dhaka Medical College Hospital, a total of 30 patients were purposively selected from May 2018 to November 2018. Patient particulars, records of physical and clinical evaluation, and operative details were collected by individual researchers. Data analysis was done by SPSS for windows version 21. Results: BDI was found very common among the age group 21 - 30 yrs (36%) and female dominant (60%). Majority of the patients presented with abdominal pain (96%), intra-abdominal collection (88%), biliary peritonitis (68%), cholangitis (60%), and obstructive jaundice (40%), and biliary fistula (40%). Laparoscopic cholecystectomy (84%) was the principal cause of biliary injury in our study. 48% of patients experienced clinical features within 7 days post-cholecystectomy. Per-operative diagnosis was done in only 12% of cases. 44% of patients in this study were recognized as Bismuth grade-3, followed by 36%, grade-2 patients. Management outcomes included wound infection (41.66%), minor bile leak (25%), peritonitis (8.33%), and renal impairment (8.33%). Conclusion: The effect of BDI is an extremely distressful clinical condition for the patients and their family members, hence proper care and management protocol should be followed.
文摘The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.
文摘Nowadays, picture fuzzy set theory is a flourishing field in mathematics with uncertainty by incorporating the concept of positive, negative and neutral membership degrees of an object. A traditional crisp relation represents the satisfaction or the dissatisfaction of relationship, connection or correspondence between the objects of two or more sets. However, there are some problems that can’t be solved through classical relationships, such as the relationship between two objects being vague. In those situations, picture fuzzy relation over picture fuzzy sets is an important and powerful concept which is suitable for describing correspondences between two vague objects. It represents the strength of association of the elements of picture fuzzy sets. It plays an important role in picture fuzzy modeling, inference and control system and also has important applications in relational databases, approximate reasoning, preference modeling, medical diagnosis, etc. In this article, we define picture fuzzy relations over picture fuzzy sets, including some other fundamental definitions with illustrations. The max-min and min-max compositions of picture fuzzy relations are defined in the light of picture fuzzy sets and discussed some properties related to them. The reflexivity, symmetry and transitivity of a picture fuzzy relation are described over a picture fuzzy set. Finally, various properties are explored related to the picture fuzzy relations over a picture fuzzy set.
文摘In this article, we define the arithmetic operations of generalized trapezoidal picture fuzzy numbers by vertex method which is assembled on a combination of the (α, γ, β)-cut concept and standard interval analysis. Various related properties are explored. Finally, some computations of picture fuzzy functions over generalized picture fuzzy variables are illustrated by using our proposed technique.
文摘Ecosystem maps are vital to represent ecological patterns and processes in a region. It enables the use of ecosystem goods and services as a robust unit for a variety of applications, including conservation planning, climate change adaptation and mitigation measures, resource management, and the economic estimation of ecosystem benefits. As different elements of eco-geological components, such as the geological, soil, and biotic assemblages organize an ecosystem;here, we developed an ecosystem map of the State of Selangor, Peninsular Malaysia, using geology, soil, elevation, and land-use data. Landsat ETM+ images, ASTER Digital Elevation Model (DEM) data, and digitized soil and geological data were integrated to develop a map of the types of ecosystem for 2005. We found 19 different natural ecosystems in the studied region that represented approximately 35% of the total land area. Among the natural ecosystems, peat-swamp forest represents highest (at ~10%), while montane ericaceous forest representing the lowest (at ~0.008%) and the hill dipterocarp quartz forest, lowland dipterocarp sandstone forest, upper dipterocarp quartz forest, and mangrove forest are representing approximately 6.4%, 4.6%, 3% and 2.6% of the total land area respectively. These data can be used to prioritize the areas deserving attention due to their value for biodiversity conservation and for the production of goods and supply of ecosystem services. In addition to a variety of ecological and environmental aspects, such an ecosystem map has potential use for the sustainable management of natural resources at the national, regional, continental, and global scales.
文摘<strong><em>Background</em></strong><span style="font-family:Verdana;"><strong>:</strong></span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Despite of different adverse events, streptokinase (SK) is widely used to treat patients presented with acute ST segment elevation myocardial infarction. </span><b><i><span style="font-family:Verdana;">Objective</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> The purpose of the present study was to observe different adverse events in patients of acute ST segment elevation myocardial infarction receiving SK infusion. </span><b><i><span style="font-family:Verdana;">Methodology</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> This cross-sectional type of analytic observational study was carried out in the inpatient department of Cardiology at National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from December 23</span><sup><span style="font-size:12px;font-family:Verdana;">rd</span></sup></span><span style="font-family:Verdana;"> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">2019 to February 22</span><sup><span style="font-size:12px;font-family:Verdana;">nd</span></sup><span style="font-family:Verdana;"> 2020 for a period of two (2) months. All patients diagnosed as acute ST segment elevation myocardial infarction receiving SK were included in the present study. Adverse events were documented through completing a questionnaire by reviewing the records in the medical file as well as interviewing with the patients. </span><b><i><span style="font-family:Verdana;">Result</span></i><span style="font-family:Verdana;">:</span></b><span style="font-family:Verdana;"> In this study, 43 (26.2%) patients developed different types of adverse events and 121 (73.8%) had no complications following SK infusion. The most common adverse event was hypotension </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verda
文摘The additional diversity gain provided by the relays improves the secrecy capacity of communications system significantly. The multiple hops in the relaying system is an important technique to improve this diversity gain. The development of an analytical mathematical model of ensuring security in multicasting through fading channels incorporating this benefit of multi-hop relaying is still an open problem. Motivated by this issue, this paper considers a secure wireless multicasting scenario employing multi-hop relaying technique over frequency selective Nakagami-m fading channel and develops an analytical mathematical model to ensure the security against multiple eavesdroppers. This mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multicasting (SOPM) to ensure the security in the presence of multiple eavesdroppers. Moreover, the effects of the fading parameter of multicast channel, the number of hops and eavesdropper are investigated. The results show that the security in multicasting through Nakagami-m fading channel with multi-hop relaying system is more sensitive to the number of hops and eavesdroppers. The fading of multicast channel helps to improve the secrecy multicast capacity and is not the enemy of security in multicasting.
文摘The Ready-Made Garments (RMG) industry is a major contributor to the economy of Bangladesh, accounting for over 80% of the country’s total exports. In recent years, the industry has faced challenges due to changing global fashion trends and increasing competition from other manufacturing countries. One of the latest trends in the fashion industry is micro seasonal fashion, which has significant impacts on the RMG industry of Bangladesh. The purpose of this study is to examine the impact of micro seasonal fashion on the RMG industry of Bangladesh. It will examine the changes in buyer and consumer behavior and demand patterns, the implications for manufacturers and suppliers, and the strategies adopted by industry players to adapt to this trend. The emergence of micro seasonal fashion has disorderly the traditional seasonal cycle of the fashion industry. Consumers are no longer satisfied with the two-season model of spring/summer and fall/winter, but instead demand new styles and trends every few weeks. This trend has created opportunities for the RMG industry of Bangladesh to cater to the fast-changing demands of consumers. Micro Seasonal Fashion also poses significant challenges for the industry. Manufacturers and suppliers must be able to produce and deliver garments quickly and efficiently, while ensuring high quality and sustainability standards. This requires investments in technology, supply chain management, and training of workers. To address these challenges, industry players in Bangladesh have adopted several strategies, such as diversifying product offerings, investing in technology and innovation, and enhancing sustainability practices. These strategies have helped the industry to remain competitive and meet the demands of fast-changing consumer preferences. The industry must be able to adapt quickly to the changing demands of consumers and invest in technology and sustainability practices to remain competitive. With the right strategies and investments, the RMG industry of Bangladesh can control the
文摘The orthogonal space-frequency block coding (OSFBC) with orthogonal frequency division multiplexing (OFDM) system reduces complexity in the receiver which improves the system performance significantly. Motivated by these advantages of OSFBC-OFDM system, this paper considers a secure wireless multicasting scenario through multiple-input multiple-output (MIMO) OFDM system employing OSFBC over frequency selective α-μ fading channels. The authors are interested to protect the desired signals from eavesdropping considering the impact of the number of multicast users and eavesdroppers, and the fading parameters α and μ. A mathematical model has been developed based on the closed-form analytical expressions of the probability of non-zero secrecy multicast capacity (PNSMC) and the secure outage probability for multi-casting (SOPM) to ensure the security in the presence of multiple eaves-droppers. The results show that the security in MIMO OSFBC OFDM system over α-μ fading is more sensitive to the magnitude of α and μ and this effect increases in the high signal-to-noise ratio (SNR) region of the main channel.
文摘Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now a challenging issue. In most cases, pantropical and regional biomass models are used frequently to estimate biomass and carbon stock in trees, but these estimation</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> have some uncertainty compared to the species-specific allometric biomass model. </span><i><span style="font-family:Verdana;">Acacia</span></i><span> <i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Casuarina</span></i> <i><span style="font-family:Verdana;">equisetifolia</span></i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Melia</span></i><span style="font-family:Verdana;"> <i>azedarach</i> </span><span style="font-family:Verdana;">have been planted in different areas of Bangladesh considering the species-specific site requirements. While </span><i><span style="font-family:Verdana;">Barringtonia</span></i><span style="font-family:Verdana;"> <i>acutangula</i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Pongamia</span></i><span style="font-family:Verdana;"> <i>pinnata</i> </span><span style="font-family:Verdana;">are the dominant tree species of the freshwater swamp forest of Bangladesh. This study was aimed to develop species-specific allometric biomass models for estimating stem and above ground biomass (TAGB) of these species using the non-destructive method and to compare the efficiency of the derived biomass models with the frequently used regional and pantropical biomass models. Four Ln-based models with diameter at breast height (DBH) and
文摘<em>Xylocarpus mekongensis</em> Pierre is the important tree species of the Sundarbans. The present study was conducted to evaluate the effect of salinity on the survival and growth of <em>X. mekongensis</em> seedlings. The distributional patterns of nitrogen, phosphorus, potassium, sodium, and carbon in seedling parts were also examined in relation to salinity. Comparatively higher survival (95%) of seedlings was observed at non-saline to slightly saline conditions (0-5 PSU) and it was decreased to 78% at 35 PSU salinity. The relative growth rate (RGR) was higher at non-saline to slightly saline (0 to 5 PSU) conditions compared to higher salinity. Nutrients, sodium, and carbon concentration are found to vary significantly (p < 0.05) among the parts of seedlings. Comparatively (p < 0.05) highest concentration of nitrogen (20 to 34 mg/g), phosphorus (0.50 to 0.75 mg/g), potassium (9 to 27 mg/g) and sodium (7 to 36 mg/g) were found in leaves, while the highest concentration of carbon (42% to 45%) was detected in the stem. However, nitrogen, potassium, and carbon concentration in different parts of seedlings showed significant (p < 0.05) negative correlations with salinity levels. It can be concluded that <em>X. mekongensis</em> has the capacity to tolerate higher saline condition but they grow well in non-saline to less saline conditions.
文摘Aegiceras corniculatum grows as single-stemmed evergreen shrub or small tree in the Sundarbans mangrove forest of Bangladesh. The objectives of this study were to derive the allometric models for estimating above-ground biomass, nutrients (N, P and K) and carbon stock in A. corniclatum. A total of 8 linear models (y = aX + b, , y = aLogX + b, Logy = aX + b, Logy = aLogX + b, y = alnX + b, Lny = aX + b and Lny = alnX + b) with 64 regression equations were tested to derive the allometric model for biomass of each plant part;and nutrients and carbon stock in total aboveground biomass. The best fit allometric models were selected by considering the values of R<sup>2</sup>, CV, R<sub>mse</sub>, MS<sub>error</sub>, S<sub>a</sub>, S<sub>b</sub>, F value, AICc and Furnival Index. The selected allometric models were Logbiomass = 0.76LogDBH<sup>2</sup> - 1.39;Biomass = 0.07DBH<sup>2</sup> - 0.49;Logbiomass = 1.04LogDBH<sup>2</sup> - 1.80;Logbiomass = 1.04LogDBH<sup>2</sup> - 0.99;= 0.48DBH - 0.13 for leaves, branches, bark, stem without bark and total above-ground biomass respectively. The selected allometric models for Nitrogen, Phosphorous, Potassium and Carbon stock in total above-ground biomass were = 0.67DBH + 0.11;= 0.94DBH + 0.08;= 1.06DBH - 0.18;= 0.33DBH - 0.09 respectively.
