Landing and distribution of captured fish in selected landing centers in Kishoreganj haor, Bangladesh

The present study illustrates species diversity, landing quality and catch composition of fish in 10 fish landing centers of 5 haor upazilas of Kishoreganj haor for 12 months from January 2018 to December 2018. A total of 15 different types of fishing gears were detected to harvest fish in different stations throughout a year. Most of the fishing (46.88%) was conducted by small groups of 2 – 5 fishers, while 24.87% of the fishing was conducted by 6 – 10 fishers. The average depth of water in haor associated rivers and inundated lands during monsoon period varied from 4.87±0.99 to 15.2±6.71 and 2.6±0.55 to 6.2±2.68 feet respectively. Fifty different types of fish species were landed in the selected 10 landing centers, where both cultured fish and captured fish were present. Fishes under the Cyprinidae family included 9 species, viz. Labeo rohita. Gebelion catla, Cirrhinus cirrhosus, Labeo calbasu, Hypophthalmichthys nobilis, Hypophthalmichthys molitrix, Cyprinus carpio, Ctenopharyngodon idella, Labeo gonius covered a maximum of 12450.61±468.32 MT. The second largest landed fish under the family Schilbeidae included 4 species Silonia silondia, Mystus armatus, Mystus cavasius Pseudeutropius atherinoides. Other fish species landed were identified as: 4 species under the family Mastacembelidae, 2 species under Siluridae, 3 species under Clupidae, 1 species under Ambassidae, 2 species under Palaemonidae, 3 species under Channidae, 1 species under Gobidae, 2 species under Bagridae and 1 species from each of the family Heteropneustidae, Pangasiidae, Clariidae, Ailiidae, Botiidae, Nandidae, Cichlidae, Anabantidae, Osphronemidae, Ambassidae, Notopteridae, Notopteridae,Belonidae and Gobiidae. Highest number 14 species landed were under catfish category, followed by 9 species of major carp. The captured total fish landed in 10 landing centers in 12 month period accounted 12,574±1029.64 MT, but the cumulative total landed fish, including pond fish, was 15,795±1666061.93 MT, as calculated by 45 Aratdars of 10 landing centers. About 88.35% fishermen sold the captured fish at local arat, but the rest (11.65%) were sold to large traders (paiker), retailers and consumers. A 56.6% of the fishermen cleaned the captured fish by river water, while 43.4% fishermen did not use water for washing fish before selling. After harvest, 45.62% fishers used clean utensils for carrying fish to arat and 54.38% used uncleaned utensils. Average harvest per fishermen per day was 23.9 kg, of which 22.26 kg was sold in the market and 1.64 kg was used for own family consumption. Out of total fish landed, a 45.2% was transported by fish hold of the country boat, 21.9% by bamboo basket and 14.8% by plastic crate. Relatively small quantity of fish was transported by insulated ice box (4.7%), aluminum container (2.7%) and gunny bag (3.2%). A 32.6% fisherman used ice and 67.4 % fishermen did not use ice after harvesting of fish. During fishing season, fish and ice ratio used by the transporters was 2.62:1. The highest number of auctioneers were found in Chamra Ghat of Karimganj, while lowest were in Nikli, with an area of 55±1.44 and 25±8.42 decimal area per auctioneers being used for fish business. Asian Australas. J. Biosci. Biotechnol. 2021, 6 (2), 75-88

Market Selling Conditions and Storage Methods Influences β-carotene Stability and Retention in Biofortified Gari

The influence of regular market selling conditions and storage methods on β-carotene stability and retention were investigated in two different biofortified gari types. Freshly processed gari samples obtained from TMS 01/1412 and TMS 01/1371 respectively were exposed to 35-450C sunlight (ESL) and 60 watts electric bulb light (EEB); stored in black polyethylene bag (SPB) and air-tight aluminum container (SAC) respectively. The stability (using area under curve analysis) and retention (%) of β-carotene in all the experiments were monitored and compared over a period of 4 weeks. Results revealed that ESL had a huge negative influence on the stability and retention of β-carotene in the two biofortified gari types. Although EEB showed minimal but progressive negative influence, SAC followed by SPB showed the least negative influence on the nutrient stability. The overall retention of β-carotene in gari processed from TMS 01/1412 and TMS 01/1371 respectively were as follows: ESL (12.1%, 12.8%), EEB (58.5%, 47.5%), SPB (61.9%, 50.8%) and SAC (60.2%, 82.6%). SAC retained the most appreciable amount of the nutrient thus suggesting it as a better form of storage while ESL lost the largest amount of the nutrient thus portraying it a detrimental market selling condition for the biofortified gari.

Experimental and Numerical Study on Melting of Solar Salt in a Finned Metallic Container

This work presents an experimental and numerical study of the melting and solidification processes of Solar Salt in a finned square metallic container with a constant heat flux source inside for the latent heat thermal energy storage (LHTES) for medium temperature applications. During the experiments the temperature of the PCM in several locations were recorded and used to validate results of numerical simulations that were conducted deploying the enthalpy method in Ansys FLUENT. Two prototypes of the container were tested, one with fins made of steel and the other with fins and casing made of aluminum, to compare the charging and discharging time in both configurations. The modelling results are in good agreement with experimental data for the charging of aluminum container and slightly higher deviation are found in the other cases. The validated simulation model can be used as a design tool to achieve the optimal geometry of the full scale LHTES for the required charging and discharging periods.

Numerical Simulation of an Aluminum Container including a Phase Change Material for Cooling Energy Storage

Thermal energy storage systems can be determinant for an effective use of solar energy, as they allow to decouple the thermal energy production by the solar source from thermal loads, and thus allowing solar energy to be exploited also during nighttime and cloudy periods. The current study deals with the modelling and simulation of a cooling thermal energy storage unit consisting of an aluminum container partially filled with a phase change material (PCM). Two unsteady models are implemented and discussed, namely a conduction-based model and a conduction-convection-based one. The equations systems relative to both the models are solved by means of the Comsol Multiphysics finite element solver, and results are presented in terms of temporal variation of temperature in different points inside the PCM, of the volume average liquid fraction, and of the cooling energy stored and released through the aluminum container external surface during the charge and discharge, respectively. Moreover, the numerical results obtained by the implementation of the above different models are compared with experimental ones obtained with a climatic chamber. The comparison between numerical and experimental results indicate that, for the considered cooling energy storage unit, free convection plays a crucial role in the heat transfer inside the liquid PCM and cannot be neglected.

Combustion synthesis method for synthesis of aluminum nitride powder using aluminum containers (II)

A combustion synthesis method was developed for synthesis of AlN powder. Al powder and small amounts of urea were thoroughly mixed and placed in aluminum containers. A layer of AlN powder was placed on the top of the reactant powdersand in between the reactant powders and the container walls. The combustion reaction was ignited by heating the top surface of the powder stack and the aluminum container was converted completely to AlN during combustion reaction. High product yields (∼99.5%) were obtained under N2 pressures of 0.3–0.5 MPa. The product as synthesized is porous and loose and can be easily ground. A quenching technique was developed and formation of the various types of product morphology was investigated. Effects of several process parameters on the product yield were also studied. These results were reported and discussed.

Combustion synthesis method for synthesis of aluminum nitride powder using aluminum containers

A combustion synthesis method was developed for synthesis of AlN powder. Al powder and small amounts of NH4Cl were thoroughly mixed and placed in low-melting-point containers made of a thin, perforated aluminum sheet. The combustion reaction was ignited by heating the top surface of the powder stack, and the aluminum container was converted completely to AlN during the combustion reaction. High product yields were obtained under N2 pressures of 0.2–0.5 MPa. The product was composed of a dense outer portion and a loose inner portion. Effects of several process parameters on the product yield were investigated and discussed.