First Synthesis of Highly Crystalline, Hexagonally Ordered, Uniformly Mesoporous TiO₂–B and Its Optical and Photocatalytic Properties

Hossain, Md. Kamal,Koirala, Agni Raj,Akhtar, Umme Sarmeen,Song, Mee Kyung,Yoon, Kyung Byung American Chemical Society 2015 Chemistry of materials Vol.27 No.19

Diversity and Composition of Tree Species in Madhupur National Park, Tangail, Bangladesh

Md. Rayhanur Rahman,Mohammed Kamal Hossain,Md. Akhter Hossain 강원대학교 산림과학연구소 2019 Journal of Forest Science Vol.35 No.3

Madhupur National Park (MNP) is one of the last remaining patches of old-growth natural Sal forest left in Bangladesh where the forest is tropical moist deciduous type. A study was revealed to assess the tree species diversity and composition in this area. For determining tree species the study was conducted through extensive random quadrat survey methods with 20 m×20 m sized plots. Results of the study indicated that there were 139 tree species belonging to 100 genera and 40 families. The quadrat survey assessed the basal area, stem density, diversity indices and importance value index of the tree species having ≥5 cm D.B.H (Diameter at Brest Height). The basal area and stem density of the tree species were 20.689±1.08 m2/ha and 1412.93±64.27 stem ha-1 while, diversity indices, i.e. Shannon-Wiener’s diversity, Simpson’s evenness, Margalef’s species richness and Pielou’s dominance indices indicated poor diversity in comparison to that of other PAs (Protected Areas) in South-Eastern region of Bangladesh. The structural composition based on height and D.B.H through reverse- J shaped curve indicated higher regeneration and recruitment but removal of trees of large growth classes. Sal (Shorea robusta) was the most dominant tree species that accounts 75% of the total tree individuals in the natural forest patches. However, some associates of Sal, i.e. Bhutum (Hymenodictyon orixensis), Gadila (Careya arborea), and Kusum (Schleichera oleosa) etc. were seemed to be rare in MNP.

Steam-assisted synthesis of uniformly mesoporous anatase and its remarkably superior photocatalytic activities

Hossain, Md. Kamal,Akhtar, Umme Sarmeen,Koirala, Agni Raj,Hwang, In Chul,Yoon, Kyung Byung Elsevier 2015 CATALYSIS TODAY - Vol.243 No.-

<P><B>Abstract</B></P> <P>The steam treatment of hexagonally ordered uniformly mesoporous (<I>h</I>-UM) amorphous TiO<SUB>2</SUB> at 120°C for 1h leads to highly crystalline <I>h</I>-UM anatase. This process is feasible for the large scale (>50g) preparation. The surface area-normalized photocatalytic activities of <I>h</I>-UM anatase for water reduction and methylene blue and 4-chlorophenol decompositions are remarkably superior to those of wormhole-like randomly mesoporous anatase and anatase nanoparticles, demonstrating an important reason to prepare anatase in UM forms. Due to the extended crystalline interconnection, the band gap energy <I>h</I>-UM anatase decreases by 0.22eV with respect to that of 25nm anatase nanoparticle.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel steam assisted highly crystalline ordered mesoporous anatase TiO<SUB>2</SUB>. </LI> <LI> High surface area with uniformly distributed hexagonal large pores is reported. </LI> <LI> Remarkably higher rate of H<SUB>2</SUB> production from water under one sun light condition. </LI> <LI> Superior photocatalytic dye degradation (MB and 4-CP) under low pressure Hg lamp. </LI> <LI> The extended crystalline interconnection decreases the band gap energy by 0.22eV. </LI> </UL> </P>

A Dynamic Channel Switching Policy Through P-learning for Wireless Mesh Networks

( Md. Kamal Hossain ),( Tan Chee Keong ),( Lee Ching Kwang ),( Yeoh Chun Yeow ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.2

Wireless mesh networks (WMNs) based on IEEE 802.11s have emerged as one of the prominent technologies in multi-hop communications. However, the deployment of WMNs suffers from serious interference problem which severely limits the system capacity. Using multiple radios for each mesh router over multiple channels, the interference can be reduced and improve system capacity. Nevertheless, interference cannot be completely eliminated due to the limited number of available channels. An effective approach to mitigate interference is to apply dynamic channel switching (DCS) in WMNs. Conventional DCS schemes trigger channel switching if interference is detected or exceeds a predefined threshold which might cause unnecessary channel switching and long protocol overheads. In this paper, a P-learning based dynamic switching algorithm known as learning automaton (LA)-based DCS algorithm is proposed. Initially, an optimal channel for communicating node pairs is determined through the learning process. Then, a novel switching metric is introduced in our LA-based DCS algorithm to avoid unnecessary initialization of channel switching. Hence, the proposed LA-based DCS algorithm enables each pair of communicating mesh nodes to communicate over the least loaded channels and consequently improve network performance.

Formulation and In vitro Evaluation of Transdermal Drug Delivery System for Galantamine

( Md. Kamal Hossain ),( Robhash Kusam Subedi ),( Myung Kwan Chun ),( Eun Jung Kim ),( Hwan Shik Moon ),( Hoo Kyun Choi ) 한국약제학회 2011 Journal of Pharmaceutical Investigation Vol.41 No.1

The effects of different formulation variables including pressure sensitive adhesive (PSA), permeation enhancer, thickness of the matrix and loading amount of drug on the transdermal absorption of galantamine were investigated across the hairless mouse skin. The permeation profile of galantamine was different depending on the types of PSA, loading amount of drug, thickness of the matrix and type of enhancer used. Highest flux of galantamine was obtained from acrylic PSA but crystals were formed in the patch within 72 h. Among the PSAs screened, crystal formation was not observed only in the patches formulated in Styrene Butadiene Styrene (SBS) matrix. Permeation rate increased linearly as the concentration of galantamine in SBS matrix increased from 2.5 to 15% w/w. Among the enhancers screened, Brij® 30 provided highest flux of galantamine. Matrix thickness of 80um was optimum for maintaining adhesiveness as well as consistently delivering galantamine for longer period of time.

Diversity and Composition of Tree Species in Madhupur National Park, Tangail, Bangladesh

Rahman, Md. Rayhanur,Hossain, Mohammed Kamal,Hossain, Md. Akhter Institute of Forest Science 2019 Journal of Forest Science Vol.35 No.3

Madhupur National Park (MNP) is one of the last remaining patches of old-growth natural Sal forest left in Bangladesh where the forest is tropical moist deciduous type. A study was revealed to assess the tree species diversity and composition in this area. For determining tree species the study was conducted through extensive random quadrat survey methods with $20m{\times}20m$ sized plots. Results of the study indicated that there were 139 tree species belonging to 100 genera and 40 families. The quadrat survey assessed the basal area, stem density, diversity indices and importance value index of the tree species having ${\geq}5cm$ D.B.H (Diameter at Brest Height). The basal area and stem density of the tree species were $20.689{\pm}1.08m^2/ha$ and $1412.93{\pm}64.27stem\;ha^{-1}$ while, diversity indices, i.e. Shannon-Wiener's diversity, Simpson's evenness, Margalef's species richness and Pielou's dominance indices indicated poor diversity in comparison to that of other PAs (Protected Areas) in South-Eastern region of Bangladesh. The structural composition based on height and D.B.H through reverse-J shaped curve indicated higher regeneration and recruitment but removal of trees of large growth classes. Sal (Shorea robusta) was the most dominant tree species that accounts 75% of the total tree individuals in the natural forest patches. However, some associates of Sal, i.e. Bhutum (Hymenodictyon orixensis), Gadila (Careya arborea), and Kusum (Schleichera oleosa) etc. were seemed to be rare in MNP.

Minimizing Sensing Decision Error in Cognitive Radio Networks using Evolutionary Algorithms

( Mohsen Akbari ),( Md. Kamal Hossain ),( Mohsen Riahi Manesh ),( Ayman A. El-saleh ),( Aymen M. Kareem ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.9

Cognitive radio (CR) is envisioned as a promising paradigm of exploiting intelligence for enhancing efficiency of underutilized spectrum bands. In CR, the main concern is to reliably sense the presence of primary users (PUs) to attain protection against harmful interference caused by potential spectrum access of secondary users (SUs). In this paper, evolutionary algorithms, namely, particle swarm optimization (PSO) and genetic algorithm (GA) are proposed to minimize the total sensing decision error at the common soft data fusion (SDF) centre of a structurally-centralized cognitive radio network (CRN). Using these techniques, evolutionary operations are invoked to optimize the weighting coefficients applied on the sensing measurement components received from multiple cooperative SUs. The proposed methods are compared with each other as well as with other conventional deterministic algorithms such as maximal ratio combining (MRC) and equal gain combining (EGC). Computer simulations confirm the superiority of the PSO-based scheme over the GA-based and other conventional MRC and EGC schemes in terms of detection performance. In addition, the PSO-based scheme also shows promising convergence performance as compared to the GA-based scheme. This makes PSO an adequate solution to meet real-time requirements.

Effect of Pre-sowing Treatments on Seed Germination and Seedling Growth of Canarium resiniferum, A Rare Native Tree of Bangladesh

Hasnat, G.N. Tanjina,Hossain, Mohammed Kamal,Alam, Mohammed Shafiul,Hossain, Md. Akhter Institute of Forest Science 2017 Journal of Forest Science Vol.33 No.3

Dhup (Canarium resiniferum) is an economically and aesthetically important rare native tree species of Bangladesh. In natural condition 78.5-98.7% seeds do not germinate due to inhibition by hard seed coat, seed predation and unfavorable environmental conditions. A study was conducted in the Seed Research Laboratory and nursery of Institute of Forestry and Environmental Sciences, Chittagong University, Bangladesh in 2013 to find out appropriate pre-sowing treatments for maximizing germination and initial seedling growth. Eleven pre-sowing treatments were provided in both the seeds sown in polybags and seeds sown in propagator house. Results revealed that, germination started at first (after 20 days of seed sown) in seeds immersed in water at room temperature for 24 hours and germination completed within 38 days. Significantly higher (p<0.05) germination percentage (33%), germination energy (16.7%), plant percent (33%) and germination value (0.4) was found with seeds immersed in water at room temperature for 24 hours. Seedling height measured at three, four and five months after the seed germination in case of seeds treated by immersion in water for 24 hours was also greater than others. Therefore, pre-sowing treatment by immersion in water at room temperature for 24 hours was more effective in germination and production of quality vigor seedlings of Dhup.

Growth density and regeneration of afforested mangroves at Mirersarai forest range in Bangladesh

Mohammad Main Uddin,Md Siddiqur Rahman,Mohammed Kamal Hossain,Salena Akter 한국산림과학회 2014 Forest Science And Technology Vol.10 No.3

The aim of the study was to determine growth performance of planted mangroves at three beats of Mirersarai forest rangein the Chittagong coastal afforestation division, Bangladesh. This 22–29-year-old mangrove plantation showed satisfactorygrowth and regeneration with variations among different study sites. The study revealed that individual species density andoverall density (stem/ha) in the study sites varied significantly (p0.05) where density of Sonneratia apetala wasmaximum among five species followed by Excoecaria agallocha, Avicennia officinalis, Ceriops decandra and Bruguierasexangula. Sonneratia apetala attained the highest mean diameter at breast height (DBH) (cm) and height (m) among allthe plantation species. It was found dominant at the middle section plantations of three beats, whereas Bruguierasexangula and Ceriops decandra were found absent at seaside plantation sites. Overall tree density was found to be highestat the middle part (1880 stem/ha) followed by inland (1610 stem/ha) and seaside (1087 stem/ha) plantations. Mean annualincrement of height and of DBH were significantly higher for Sonneratia apetala (0.42 m/year, 0.81 cm/year) followed byAvicennia officinalis (0.32 m/year, 0.67 cm/year), Bruguiera sexangula (0.18 m/year, 0.40 cm/year), Excoecaria agallocha(0.16 m/year, 0.30 cm/year) and Ceriops decandra (0.05 m/year, 0.10 cm/year), respectively. Regeneration of vegetationsshowed promising performance in three beats. Sonneratia apetala showed rich regeneration at seaside plantations thaninner parts in northern beats than those of southern beats. For all beats this species has an increased regeneration frominland to seaside plantation strips. Avicennia officinalis seedlings were found highest at the middle part of the plantation,whereas Excoecaria agallocha was found to be regenerated with high density at the inland part with a decreasing trendtoward seaside strips. However, Bruguiera sexangula was found to be regenerated only at inland strips. Thus, this suggeststhat a coastal afforestation program with different species will show varied growth, regeneration and density at differentsituations according to species ecology and adaptability to the sites along the coast .

Coastal Afforestation Effect on Soil Physiochemical Properties at Sitakunda Coast of Chittagong, Bangladesh

Mamun, Abdullah-Al,Kabir, Md. Humayain,Kader, Mohammed Abdul,Hossain, Mohammed Kamal Institute of Forest Science 2021 Journal of Forest Science Vol.37 No.1

This study was conducted at Sitakunda coastal afforestation range, comprised of four beats- Bansbaria, Bakkhali, Baterkhil and Bogachattar, in Chittagong. Afforestation effects on soil physicochemical properties in comparison to adjacent barren land were analysed. In the study area, an area of 3277.33 ha was planted with Sonneratia apetala, Avecinnia officinalis, Excoecaria agallocha, Bruguiera sexangula, Ceriops decandra from 1968 to 2011. We found positive soil physicochemical changes in plantations in comparison to adjacent barren land. Soil bulk density of plantation was lower than the adjacent barren land. Soil pH and soil salinity were significantly higher in barren land whereas soil organic matter, organic carbon, nitrogen, phosphorus, potassium of plantations were higher in afforested land. Soil texture ranged from clay loam to sandy loam in different depth of these two types of land. However, this study concludes that there is clear evidence that afforestation has positive impacts on all soil properties in different location and soil depths in the study area.