Economics of Finishing Pigs in Hoop Structures and Confinement: A Summer Group under Different Space Restrictions
The study was conducted at the ISU Rhodes Research and Demonstration farm. The two types of pork grow-finish production facilities compared in this study are hoop and total confinement. This is the eighth group of finishing pigs that has been evaluated in these facilities and the forth summer group. This study was conducted from April 2001 to September 2001. 
Past reports examined the differences between the two facility types to evaluate facility performance under summer and winter seasons. This report similarly examines the difference between the two facility types. An additional focus of this group is pig stocking density rates. Stocking rates of 9, 10.5, and 12 square feet per pig are evaluated for the hoop system. Net revenue per pig for the hoop systems were $19.79 (12 square feet), $22.41 (10.5 square feet), and $17.74 (9 square feet), respectively. The net revenue per pig for the confinement system was $16.25 per pig. 
The hoop facilities showed a dramatic drop in production efficiency when the facilities were stocked at a rate of 9 square feet per pig. The feed conversion increased nearly a tenth of a pound of feed per pound of gain and the average daily gain decreased by .6 pounds per day compared with the other stocking densities. However, feed efficiency and average daily gain only improved slightly when the space allowed per pig was 12 square feet compared with 10.5 square feet. Moreover, the reduction in space per pig from 12 to 10.5 square feet allowed a more efficient use of both facilities and bedding per pig. This allowed the group stocked at 10.5 square feet per pig to increase net revenue by $2.62 per pig over the hoop stocked at 12 square feet per pig. This difference is impacted somewhat by a difference in the weight of the pigs that were marketed (Table 1). They were on feed for a slightly longer time period. Despite this difference in sale weight the study suggests that a decrease in space utilized from 12 to 10.5 square feet per pig would increase the profit level for hoop facilities during the summer. 
Net revenue for the hogs from the hoop facility with 12 square feet of space was $3.54 per pig over the confinement system. This difference was greater than the average of the three previous summer groups, which favored the hoops by $1.43 and saw a difference in hoop net revenue vs. confinement net revenue that ranged from $.20 to $3.05 per pig. The range of differences can be explained by a number of reasons. Some can be attributed to on farm research variables such as weather and disease exposure. Another key issue is the distribution of marketing. This changes the performance of the remaining hogs as well as the average sale weight
Analysis of Growth of Pigs in Grow-Finish Facilities
Introduction Pork production is a dynamic and ever-changing industry. Producers are continually evaluating pork production systems, with the goal of improving or maintaining their competitive position. Production systems range from totally enclosed confinement to pasture systems. Although the method of finishing hogs in hoop structures is not necessarily new, it is a system with a renewed focus in the industry. The Iowa State University Rhodes Research Farm is a research site of hoop as well as confinement pork production. The facilities at the Rhodes Farm consist of three hoop structures and one modular confinement unit. The focus of this report is to evaluate growth of growfinish pigs in a hoop system and provide a comparison to a confinement system. At this time, there have been three groups of pigs finished in each system: winter 97/98, summer 98, and winter 98/99. This report provides pig growth functions for the summer 98 and winter 98/99 production period along with the annual results. Although this report focuses on the second (summer) group and third (winter) group of pigs that were finished in the facility, the basic facility research will eventually contain results from at least five feeding trials over at least a 2-year period and with more than 2500 pigs.
Numerical Simulation for Natural State of Two-Phase Liquid Dominated Geothermal Reservoir with Steam Cap Underlying Brine Reservoir
Hydrothermal reservoir which liquid-dominated hydrothermal reservoir is a type of geothermal reservoir that most widely used for power plant. The exploitation of mass and heat from the geothermal fluid will decrease the pressure in the reservoir over time. Therefore the pressure drop in the reservoir will have an impact on the formation of boiling zones or boiling will increase. The impacts are an increase in the fraction of steam, dryness, in the reservoir and with good vertical permeability will form a steam cap underlying the brine reservoir. The two- phase liquid dominated reservoir is sensitive to the porosity and difficult to assign average properties of the entire reservoir when there is boiling zone in some area of the reservoir. These paper showed successful development of two-phase liquid dominated geothermal reservoir and discussed the formation of steam cap above brine reservoir through numerical simulation for state natural conditions. The natural state modeling in steam cap shows a match with the conceptual model of the vapor-dominated developed. These paper also proofed the presence of transition zone, boiling zone, between steam cap and brine reservoir.