Experimental study on similarity simulation of air leakage and transport in multi-layer composite goaf above and below the shaft

During the mining process of multi-layer composite coal seams, the mining of the lower coal seam causes severe air leakage in the upper goaf, which exacerbates the spontaneous combustion of residual coal in the goaf. In order to prevent the occurrence of coupled disasters of coal spontaneous combustion and gas explosion, similar physical simulation experiments were conducted to study the law of air leakage and transportation in coal mine goaf. A multi-layer composite goaf simulation system was designed. Based on the situation of 22310 working face in Bulianta Coal Mine, simulation experiments were conducted using two ventilation methods: extraction type and pressing type, with controlled air flow rates of 4.4×10−3, 5.9×10−3, 7.4×10−3 m3/min. The distribution patterns of oxygen volume fraction in the goaf under different ventilation methods and the spatial distribution law of coal spontaneous combustion risk areas in multi-layer composite goaf were obtained. The results show that the impact area of oxygen volume fraction in press-in ventilation is relatively large, with high oxygen volume fraction in both direction and inclination, and the impact height is below 0.5 m from the bottom plate; the impact of the extraction type on the oxygen volume fraction in the goaf involves the top layer, manifested as local effects, and the distribution of oxygen volume fraction contour lines presents a “funnel shape”

Influence of feeding operation and social factors on cattle locomotion in free stall barns

The influence of feeding operation and social factors on voluntary movement of cattle was studied with a group of nine Holstein calves in free stall barns. The results of this study suggest that cattle can move more voluntarily when rations are put beyond the place that farmers want them to walk through. The results also suggest that conflicts between motivations for approaching rations and avoiding competitive feeding behaviour should be considered when efficient systems of locomotion control of cattle groups are designed, such as in AMSs. Key words: Dairy cattle, feeding, social behaviour, motivation </jats:p

Simulations of Future Trends in Welfare-Centric Egg Production Systems: Impacts on Productivity and Prices

The implementation of more animal welfare-centric livestock production systems holds considerable potential for achieving sustainable production in Japan. However, such systems generally reduce productivity per unit area, impose financial burdens on farmers that adversely affect their physical and mental health, and require increased consumer awareness. In particular, declines in productivity per unit area substantially affect the farming economy, giving rise to concerns about the sufficient egg production for the population, which consequently exacerbates Japan’s food security concerns.In this study, our goal was to predict temporal trends in the Japanese transition to welfare-centric facilities by analyzing desired egg consumption. We formulated five scenarios, ending in 2050, to assess the future impact of changing the proportions of types of egg production on total production, numbers of hens, total farm area, production costs, and retail prices. Multiple issues were identified in our analysis. First, Japanese production uses conventional caging, which provides high efficiency, maximum output, and decreased prices. Our simulations suggest that ensuring optimal production is likely to present challenges as animal welfare is addressed. They also suggest that the poultry industry or the Japanese government will likely need to plan changes in production methods will likely be necessary to prevent egg surpluses and/or shortages. Additional issues were identified, including price increases, numbers of hens, total farm area, and production costs. This study offers valuable insights for policymakers in their decision-making processes to help optimize production methods while considering food security, animal welfare, and farmers’ welfare

Effect of low salinity on the survival of postlarvae of the blue shrimp, at different stages

The development of low salinity culture techniques is the major factor that facilitated the wide- spread cultivation of the white shrimp Litopenaeus vannamei in China. Similarly, adaptation to fresh or low salt water is critical for the commercial farming of a related species, the blue shrimp L. stylirostris. To determine the effects of low salinity on L. stylirostris development, the survival of postlarvae was investigated at different levels of salinity at the Haichang Jinhaian Shrimp Breeding Farm and Gulangyu Breeding Farm for Aquatic Animals of the Fisheries Research Institute of Fujian during 2002-2003. Results showed that both salinity and the age of the post- larvae significantly affected survival (p&lt;0.01). The minimum seawater salinity for young postlar- vae was 10-14 ppt and survival rates increased with age. When the post-larvae were 9 days old or older (≥P9), survival did not significantly differ in the low salinity treatments from that of the control (P12). The first hour was the most critical period. If larvae survived the first hour, they usually survived the whole study period (24 h) or longer.</jats:p

Effect of low salinity on the survival of postlarvae of the blue shrimp, at different stages

The development of low salinity culture techniques is the major factor that facilitated the wide- spread cultivation of the white shrimp Litopenaeus vannamei in China. Similarly, adaptation to fresh or low salt water is critical for the commercial farming of a related species, the blue shrimp L. stylirostris. To determine the effects of low salinity on L. stylirostris development, the survival of postlarvae was investigated at different levels of salinity at the Haichang Jinhaian Shrimp Breeding Farm and Gulangyu Breeding Farm for Aquatic Animals of the Fisheries Research Institute of Fujian during 2002-2003. Results showed that both salinity and the age of the post- larvae significantly affected survival (p<0.01). The minimum seawater salinity for young postlar- vae was 10-14 ppt and survival rates increased with age. When the post-larvae were 9 days old or older (≥P9), survival did not significantly differ in the low salinity treatments from that of the control (P12). The first hour was the most critical period. If larvae survived the first hour, they usually survived the whole study period (24 h) or longer