gamma - Al(2)O(3)-Coated Porous Silicon for Trace Moisture Detection

A simple moisture sensor working at room temperature has been fabricated using porous silicon (PS) coated with porous gamma-aluminium oxide (gamma - Al(2)O(3)). Porous silicon was formed by electrochemical anodization of p-type silicon. Thereafter, a porous layer of the PS was dip coated with gamma - Al(2)O(3) film. The gamma - Al(2)O(3) coating solution was made by a simple sol-gel method. The coated structure was sintered at 500 degrees C for 30 m to form a nano porous layer of metal oxide on the porous silicon. Sintering the gamma - Al(2)O(3)-coated PS sample improves the stability of the sensor. Two different sensors with membrane-type metal contact have been fabricated by varying electrochemical parameters of PS. The sensors were tested to detect low moisture content in the N(2) gaseous atmosphere in the range of 25 to 200 mu l. Results show that suitable pore morphology of the hybrid structure will enable one to obtain characteristics of a sensor comparable to the commercial porous alumina moisture sensor. It was further observed that the sensor output is highly reproducible and has negligible hysteresis

Pig raising practices by unprivileged, ethnic people in Bangladesh

We interviewed 207 pig raisers from seven different districts of Bangladesh to explore their practices related to their pig farming. We used structured questionnaires to interview the pig raisers and used descriptive statistics for analysis. Most of the pig raisers (54%) were illiterate. 50% (104) of them had a monthly income of less than 10000 BDT and 60% (124) were landless. Most of the pig raisers (92%, 191) were rearing local breed and 67% of them were practicing semi-scavenging system. As feed source 55% (114) pig owners used kitchen waste and 54% (111) used rice husk. The pig raisers mentioned different types of challenges such as social problem (16%), disease (50%), less profitable (20%) and unavailability of feed (19%). In our study, we found that 31% respondents visited veterinarians, 28% visited quack and 21% do not take any action when their pigs were sick. Only 16% pig raisers used vaccines against different infectious diseases and 36% used anthelmintics against parasitic diseases. Awareness buildup of the pig raisers may help them raising pigs in a better way which will improve the farming system and reduce the probability of disease transmission