Experimental Estimation of the Heat Transfer Coefficient of an Unglazed Solar Plate for Unsteady Humid Outdoor Condition

This research presents a study on the heat transfer coefficient for an unglazed solar plate collector in an unsteady humid outdoor environment. The purpose for undertaking this research is to investigate the correlation between the heat transfer coefficient and air speed and also verify whether heat transfer from unglazed solar thermal collectors under outdoor conditions can be experimentally determined using a particular mathematical relationship for different locations. In estimating the heat transfer coefficient for an unglazed solar plate in an unsteady humid outdoor condition, an experiment was held using an outdoor setup that measured temperatures, wind speeds, and solar radiations from 11:00 A.M. to 2:00 P.M. The solar plate collector was placed on a flat bed of height 2.2 m and a collection area of 0743 m2. An average temperature of 45°C was recorded for a mild steel plate collector which was initially exposed to an ambient temperature which ranges from 25°C to 32°C. The interfacial temperature between the plate and an asbestos board ranges from 42°C to 52°C, and that of the asbestos and a plywood is 40°C to 46°C. The specific heat capacity of the mild steel plate and the asbestos board used for the construction of the experimental setup are 25.00 kJ/kg and 950.00 kJ/kg, respectively, while the thermal conductivity of these materials is 0.46 W/m·K and 0.25 W/m·K, respectively. The novelty of this work is the use of such a study to generate empirical equations for Ghana and to produce representative equations for determining the heat transfer coefficient for solar plate collectors in unsteady humid outdoor conditions in West Africa. This work is expected to contribute data alongside similar works done for different areas to help propose empirical equations for estimating global and not site-specific heat transfer coefficients.

Small Scale Home Drying of Indigenous Fish Species in Urban High-Rises at Dhaka Metro

Drying is one of the common and ancient methods of fish preservation and is generally done in a wide range of open space. This study attempt to evaluate fish drying method at high-rise urban households with three small indigenous fishes namely Mola (Amblypharyngodon mola), Chapila (Gudusia chapra) and Lal Khailsha (Trichogaster lalius). Fishes were dried at high-rise indoor veranda and outdoor rooftop conditions. The dry weight of Mola, Chapila and Lal Khailsha fishes were 70%, 69.5% and 72% in indoor condition and 71.1%, 70.5% and 73% in outdoor condition. The differences of drying capacity between the indoor and outdoor dried fishes were none (p<0.05), thus, the both drying methods are feasible for the urban lifestyle. In dry state, the moisture level in Mola, Chapila and Lal Khailsha were 6.45%, 7.89% and 7.82% whereas, the protein level were 66.51%, 72.26% and 62.02% respectively. The ash value found in the respective fishes was 10.05%, 12.18% and 16.07% and the amount of total fat was 11.14%, 11.28% and 12.32% respectively. The protein and moisture values showed an inverse relationship between the indoor and outdoor condition. The preference analysis of dried fish was found to be highly (100%) accepted among the dry fish-eating consumers from Chittagong, Lakhimpur, Mymensingh, Rangpur, Bandarban, Pabna and Sylhet districts. On the contrary, in case of the consumers of Barisal and Chandpur districts, the level of acceptance was none (0%), whereas the consumers of Kushtia district have accepted the dry fish moderately (60%). Bangladesh J. Zool. 49(1): 117-124, 2021

HIỆU QUẢ CỦA PHƯƠNG PHÁP XẾP MÔ VÀ ĐỐT ÁO MÔ ĐẾN SINH TRƯỞNG VÀ NĂNG SUẤT NẤM RƠM (Volvariella volvacea) TRỒNG NGOÀI TRỜI

Mục tiêu của nghiên cứu là xác định phương pháp xếp mô và đốt áo mô đối với trồng nấm rơm ngoài trời. Thí nghiệm được bố trí khối hoàn toàn ngẫu nhiên với 05 lần lặp lại, mỗi lặp lại là 01 dòng dài 1,5 m. Các nghiệm thức (NT) gồm: NT1: Gối - Đốt áo mô, NT2: Cuộn - Đốt áo mô, NT3: Khuôn ngửa - Đốt áo mô, NT4: Khuôn úp - Đốt áo mô, NT5: Gối - Không đốt áo mô, NT6: Cuộn - Không đốt áo mô, NT7: Khuôn ngửa - Không đốt áo mô, NT8: Khuôn úp - Không đốt áo mô. Kết quả cho thấy nhiệt độ mô nấm ở giai đoạn ủ tơ và hình thành quả thể đều phù hợp với sinh trưởng và phát triển của nấm rơm. Chiều dài, chiều rộng của 30 quả thể xuất hiện đầu tiên và khối lượng trung bình/quả thể không bị ảnh hưởng bởi phương pháp xếp mô kết hợp đốt áo mô, hoặc không đốt áo mô. Xếp mô theo phương pháp cuộn và khuôn ngửa kết hợp đốt áo mô có thời gian xuất hiện quả thể sớm hơn so với các nghiệm thức tương ứng nhưng không đốt áo mô trong khi các phương pháp xếp mô kết hợp đốt rơm có thời gian kết thúc thu hoạch chậm hơn, ngoại trừ phương pháp xếp mô theo khuôn ngửa kết hợp đốt áo mô. Tổng khối lượng quả thể và số lượng quả thể/1,5 m mô của phương pháp xếp mô cuộn kết hợp đốt áo mô (2,82 kg và 339,8 quả thể) cao hơn tương ứng so với chỉ xếp mô cuộn (2,50 kg và 307,0 quả thể). ABSTRACT The objective of this study was to determine the proper bed design (BD) and burning of dry rice straw cover (BDRSC) to improve of rice straw mushroom (RSM) yield. A completely randomized block (CRB) experiment was carried out based on incubated rice straw bed under outdoor condition with 8 treatments and 5 replications, each replication as a row length of 1.5 m. The treatments included (1) Packing of rice straw (RS) - BDRSC, (2) Rolling of RS - BDRSC (3) Upward wood frame (UWF) containing RS - BDRSC, (4) Downward wood frame (DWF) containing RS- BDRSC, (5) Packing of RS– without BDRSC, (6) Rolling of RS - without BDRSC, (7) UWF - without BDRSC and (8) DWF - without BDRSC. The results showed that the temperature of bed met the demand of the growth and development of RSM. The length and width of the first 30 mushroom fruiting bodies (MFB) and mean weight per a MFB have not affected by bed types either BDRSC or without BDRSC. The BD as rolling of RS and UWF with BDRSC early produced MFB as compared to each corresponding treatment while BD with BDRSC expanded the harvest period, the exception for BD with UWF in combination with BDRSC. Total number of MFB and mean weight per 1.5 meter of rolling of RS incorporation of BDRSC (2.82 kg and 339.8 MFB) were higher than only rolling of RS (2.50 kg and 307.0 MFB), respectively.

Pendidikan Pembebasan : Telaah Terhadap Pemikiran Paulo Freire

Nowadays, education tends to ignore the value of human being which consists of the liberation. The liberation value in human individual is taken by another person who yells out democracy. We can find the real fact in reality where one person takes another person’s right through an institution with democracy and quality reasons. An education scientist, Paulo Freire, gives an illustration that education today through formal institution makes robot in human who work as mechanic machine, where their independent to act and express the ideas is limited. In simple way, Freire points out that, “The absolute consistency will make life becomes worthless, discolor, and cannot be felt experience.” Based on the statement above, Freire has deschooling concept, the concept of study without schooling. It’s because the study can be done out of the formal school even in outdoor condition.