STR-931: TIMBER I-JOISTS WITH WEB OPENINGS: REINFORCEMENT, CAPACITY PREDICTION AND SENSITIVITY ANALYSIS

Timber I-joists are a popular product in light-frame wood construction in North America. The design with timber I-joists, however, has not yet achieved the same level of refinement compared to reinforced concrete or steel structures. One of the reasons is that timber I-joists have higher variability in their material properties than more homogeneous building materials. Additionally, although very commonly applied in practice, engineers and practitioners have limited knowledge and guidance for I-joists with web opening. As a result, in many cases the design of timber I-joists based on manufacturer’s specifications lead to very conservative solutions. The present research predicts the capacity of unreinforced and reinforced timber I-joists with openings from experimental results. A total of 100 unreinforced and 100 reinforced I-joists with opening were tested under four point loading. The capacity of the I-joists with opening was predicted from regression analysis. A sensitivity analysis was performed for the predicted equations using Meta-model of Optimal Prognosis (MOP) to evaluate the contribution of each parameter on the model responses. The research demonstrates that the reinforcement technique was efficient for I-joists with openings and the proposed equations were very accurate to predict the I-joists capacity

Comparative economic analysis of pond fish production in Mymensingh and Jessore Districts, Bangladesh

The study was conducted to determine the cost, return and relative profitability of pond fish production of Mymensingh and Jessore districts. A total of 75 ponds were selected on the basis of purposive random sampling technique from 7 villages under 2 Upazila (Trishal and Gouripur) of Mymensingh districts and 8 villages under 4 Upazila (Monimmpur, Jhikorgacha, Chowgacha and Sadar) of Jessore district. It was found that per hectare per year gross cost of pond fish production in Mymensingh and Jessore were Tk 333457.75 and Tk 54327.74, while gross return were Tk 434131.16 and Tk. 96640.00 and net return were Tk 100673.41 and Tk. 42312.26, respectively. The findings of this study revealed that the pond fish production in Jessore district was more profitable than that of Mymensingh district. Cobb-Douglas production function was applied to realize the specific effect of the factors on pond fish production. Out of six variables included in the function three variables had positive impact on return from pond fish production, in Mymensingh district but five variables had positive impact on return from pond fish production in Jessore distric

Conjugate Effects of Radiation and Viscous Dissipation on Natural Convection flow over a Sphere with Pressure Work

ABSTRACT The effects of viscous dissipation and radiation on natural convection flow along a sphere with pressure work have been investigated. The governing equations are transformed into dimensionless non-similar equations by using set of suitable transformations and solved numerically by the finite difference method along with Newton's linearization approximation. We have focused our attention on the evaluation of velocity profiles, temperature profiles, shear stress in terms of local skin friction and the rate of heat transfer in terms of local Nusselt number for different values of radiation parameter, Prandlt number, heat generation parameter, magnetic parameter, joule heating parameter and viscous dissipation parameter and the numerical results have been shown graphically

Genetic variation of wild and hatchery populations of the catla Indian major carp (Catla catla Hamilton 1822: Cypriniformes, Cyprinidae) revealed by RAPD markers

Genetic variation is a key component for improving a stock through selective breeding programs. Randomly amplified polymorphic DNA (RAPD) markers were used to assess genetic variation in three wild population of the catla carp (Catla catla Hamilton 1822) in the Halda, Jamuna and Padma rivers and one hatchery population in Bangladesh. Five decamer random primers were used to amplify RAPD markers from 30 fish from each population. Thirty of the 55 scorable bands were polymorphic, indicating some degree of genetic variation in all the populations. The proportion of polymorphic loci and gene diversity values reflected a relatively higher level of genetic variation in the Halda population. Sixteen of the 30 polymorphic loci showed a significant (p < 0.05, p < 0.01, p < 0.001) departure from homogeneity and the FST values in the different populations indicated some degree of genetic differentiation in the population pairs. Estimated genetic distances between populations were directly correlated with geographical distances. The unweighted pair group method with averages (UPGMA) dendrogram showed two clusters, the Halda population forming one cluster and the other populations the second cluster. Genetic variation of C. catla is a useful trait for developing a good management strategy for maintaining genetic quality of the species

Participatory and Institutional Approaches to Agricultural Climate Services: A South and Southeast Asia Regional Technical & Learning Exchange

In order to share experience and boost capacity in agricultural climate services, a three-day workshop titled ‘Participatory and Institutional Approaches to Agricultural Climate Services Development: A South and South East Asia Regional Technical and Learning exchange” was held between September 17-19, 2017, in Dhaka, Bangladesh, with more than 50 leaders in agricultural climate services from 11 countries attending. The workshop was sponsored by the U.S. Agency for International Development (USAID) behalf of the Climate Services for Resilient Development (CSRD). The workshop was organized by the International Maize and Wheat Improvement Center (CIMMYT) alongside the SERVIR and Climate Services Support Activity and CSRD South Asian partners

Solar photovoltaic technology and Bangladesh

The geography and topography of Bangladesh has created many rural and remote areas. The progress of rural electrification in Bangladesh faces specific problems because of the scarcity of power generation. The major electricity grid and a number of isolated local grids cannot economically reach many rural areas. A photovoltaic system is one suitable solution because of its flexibility, low environmental impact and freedom from fuel requirements. Therefore photovoltaic technology is a most feasible option to provide an alternative source of energy in areas where conventional grid electrification is a major issue. Various photovoltaic systems ranging from solar home systems, photovoltaic-pumping systems for drinking water, TV repeaters, public health centers, institutions and office systems have been installed in Bangladesh. More recently PV system are also effectively used in income generating enterprises such as grocery shops, tailoring shops, clinics, restaurants, rice mills, cellular phone services, barber shops, buzzers, and micro utilities which sell electricity to customers in the neighborhood. And Solar PV also introduced in the electrification of cyclone shelter in the coastal areas

A compact reconfigurable antenna with wide tunable frequency and 360° beam scanning

A compact microstrip-fed antenna, which consists of two radiating rings and two parasitic strips, is proposed for frequency- and pattern- reconfigurability. The resonant frequency is tuned within a tuning range of 24.7% by controlling the input impedance at the rings using two varactor diodes. By regulating the radiation from the rings and changing the operation of the strips from reflector to director and vice versa, beam-steerability is realized for nearly 360&#x00B0; azimuth scanning. A prototype is built on FR4 substrate and tested to validate the concept. Despite having a compact size and thin profile (0.27&#x03BB;0 $\times$ 0.34&#x03BB;0 $\times$ 0.005&#x03BB;0, &#x03BB;0 at the lowest frequency), the antenna with its simplified mechanism possesses multiple functions that are comparable with array antennas for similar purposes

Improved communications in underground mines using reconfigurable antennas

Fixed performing antennas are ineffective in providing optimum performance in a changing multi-path environment, such as underground mines where channel conditions quickly change as the antenna is moved. Hence, we investigated the performance of a pattern reconfigurable antenna in improving the wireless communications link in a hard rock underground mine. A reconfigurable antenna and a dipole were characterized and compared in line-of-sight (LOS) and non-line-of-sight (NLOS) propagation scenarios. As a proof of concept, experiments were performed at the University of Queensland Experimental Mine using a 1 GHz frequency band centered at 2.45 GHz. Analysis of complex channel impulses captured through frequency domain channel sounding is presented. Also, the results show that reconfigurability in the rich multipath environment achieves a 20&#x0025; and 34&#x0025; improvement in path loss and delay spread, respectively, compared to a fixed-beam antenna in NLOS propagation. Furthermore, more than 34&#x0025; improvement in coherence bandwidth is observed in LOS and NLOS. Therefore, reliable high-data rate communication is achievable in underground mines by the effective management of multipath effects using the reconfigurable antenna

Genetic polymorphism in rice (Oryza sativa L.) through RAPD analysis

224-229Random Amplified Polymorphic DNA (RAPD) assay was performed to estimate genetic polymorphism in six different rice (Oryza sativa L.) cultivars viz. Basmati 370, DM 25, IRATOM 24, Binadhan 6, TNDB 100 and Y 1281. Three out of the 15 decamer random primers showed amplification of genomic DNA in 24 individuals. The primers produced a total of 26 bands of which 14 were polymorphic. Proportion of polymorphic bands and gene diversity estimates were 26.92% and 0.09 for Basmati 370, 11.54% and 0.04 for DM 25, 11.54% and 0.05 for IRATOM 24, 7.69% and 0.02 for Binadhan 6 and 23.08% and 0.11 for TNDB 100 whereas Y 1281 cultivar was monomorphic indicating the existence of high level of intra cultivar genetic variation in Basmati 370 and TNDB, respectively 100. High levels of population differentiation (GST = 0.75) and low levels of gene flow (Nm = 0.16) estimates across all the loci indicate sufficient existence of genetic variation among these six cultivars. Low intra cultivar variation and significant differentiation in different cultivar pairs was observed at a number of loci. Nei’s genetic distances estimated among the different pairs of cultivars were correlated with geographical distances. The UPGMA dendrogram based on Nei’s genetic distance clubbed the cultivars into three clusters. RAPD analysis showed promise as an effective tool in estimating genetic polymorphism in different rice cultivars