Circular 87

High rates of female breeding success and offspring survival are the two major factors in productivity of any commercial livestock industry. To im prove breeding success and offspring survival, the herd m anager will establish selection criteria and choose which males and females will breed. The genetics or characteristics of future animals will reflect their parentage. Selection pressure is evident in both wild and captive populations of herbivores. Predators, environment, and human harvest strategies are a few forces which influence the characteristics of freeranging populations of reindeer, caribou, moose, wapiti, etc. In livestock production systems, herd managers often breed for specific characteristics such as larger body size, high birth and growth rates, leanness, etc. A single color or combination of colors has been another characteristic often selected by purebred cattle producers as well as reindeer herders

Someday We\u27ll Be Happy

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A Comparison of Risk Assessment Models for Pipe Replacement and Rehabilitation in a Water Distribution System

A water distribution system is composed of thousands of pipes of varying materials, sizes, and ages. These pipes experience physical, environmental, and operational factors that cause deterioration and ultimately lead to their failure. Pipe deterioration results in increased break rates, decreased hydraulic capacity, and adverse effects on water quality. Pipe failures result in economic losses to the governing municipality due to loss of service, cost of pipe repair/replacement, damage incurred due to flooding, and disruptions to normal business operations. Inspecting the entire water distribution system for deterioration is difficult and economically unfeasible; therefore, it benefits municipalities to utilize a risk assessment model to identify the most critical components of the system and develop an effective rehabilitation or replacement schedule. This study compared two risk assessment models, a statistically complex model and a simplified model. Based on the physical, environmental, and operational conditions of each pipe, these models estimate the probability of failure, quantify the consequences of a failure, and ultimately determine the risk of failure of a pipe. The models differ in their calculation of the probability of failure. The statistically complex model calculates the probability of failure based on pipe material, diameter, length, internal pressure, land use, and age. The simplified model only accounts for pipe material and age in its calculation of probability of failure. Consequences of a pipe failure include the cost to replace the pipe, service interruption, traffic impact, and customer criticality impact. The risk of failure of a pipe is determined as the combination of the probability of failure and the consequences of a failure. Based on the risk of failure of each pipe within the water distribution system, a ranking system is developed, which identifies the pipes with the most critical risk. Utilization of this ranking system allows municipalities to effectively allocate funds for rehabilitation. This study analyzed the 628-pipe water distribution system in the City of Buellton, California. Four analyses were completed on the system, an original analysis and three sensitivity analyses. The sensitivity analyses displayed the worst-case scenarios for the water distribution system for each assumed variable. The results of the four analyses are provided below. Risk Analysis Simplified Model Complex Model Original Analysis All pipes were low risk All pipes were low risk Sensitivity Analysis: Older Pipe Age Identified 2 medium risk pipes Identified 2 medium risk pipes Sensitivity Analysis: Lower Anticipated Service Life Identified 2 medium risk pipes Identified 9 high risk pipes and 283 medium risk pipes Sensitivity Analysis: Older Pipe Age and Lower Anticipated Service Life Identified 1 high risk pipe and 330 medium risk pipes Identified 111 critical risk pipes, 149 high risk pipes, and 137 medium risk pipes Although the results appeared similar in the original analysis, it was clear that the statistically complex model incorporated additional deterioration factors into its analysis, which increased the probability of failure and ultimately the risk of failure of each pipe. With sufficient data, it is recommended that the complex model be utilized to more accurately account for the factors that cause pipe failures. This study proved that a risk assessment model is effective in identifying critical components and developing a pipe maintenance schedule. Utilization of a risk assessment model will allow municipalities to effectively allocate funds and optimize their water distribution system. Keywords: Water Distribution System/Network, Risk of Failure, Monte Carlo Simulation, Normal Random Variable, Conditional Assessment, Sensitivity Analysis

Yields and nutrient relationships of corn grown in small grain-legume cover crops

Rising energy costs and high soil erosion losses are causing many farmers in West Tennessee to turn to no-tillage methods of production. This study, con-ducted during the growing season of 1980 at Milan, Tennessee, evaluated the effects of utilizing a legume in the no-till mulch on the growth, yield, and nutrient relationships of corn (Zea mays L.). Corn planted into a hairy vetch (Vicia villosa Roth.) and wheat (Triticum aestivum L.) mixture under both conventional and no-tillage was compared to no-tillage into a wheat alone mulch and to a check plot consisting of corn grown by conventional tillage into bare ground. These four treatments were compared at rates of 56, 112, and 168 kg/ha of nitrogen as NH4NO3. Tissue samples for dry matter weight and elemental analysis were taken of the wheat and wheat-vetch cover crops before corn planting and of the corn at five dates during the growing season. The corn was planted on April 30 and harvested September 12. The dry matter yield and N content of the wheat-vetch cover crop was lower than expected. This resulted in a very low N contribution from the mulch. Stover weight values were similar for all treatments across sampling dates at the non-zero N rates and the rate of dry matter production declined during the latter part of the growing season. These results reflect the severe moisture stress during this period. There appeared to be some immobilization of N under the no-till mulches. The WNT (wheat, no-tillage) treatment required the most supplemental N fertilization to reach its yield maximum. Also, the stover dry matter yield of both no-till treatments was lower than the conventional during the early part of the growing season. The analysis of variance for grain yields indicates that tillage was necessary to release the legume N and that there did not appear to be any priming effect from the addition of inorganic fertilizer N. These conclusions follow from the significant F value for the WVC vs. WVNT comparison and its insignificant interaction with N rates. Stover N content was significantly increased by additional fertilizer N. In some comparisons between treatments and between N rates, when dry matter and grain production were low there was a concomitant increase in the N content of the stover. There were significant decreases in the P and K percentages of the stover as the supplemental N rate was increased. These percentages also declined with increas-ing dry matter production. A concentration effect caused by low dry matter production at the low N rates during the first half of the growing season resulted in significantly higher stover P% values for the no-tillage treatments. A comparison of the data on stover yield and phosphorus uptake reveal that the wheat-vetch residue released available phosphorus at the 0 and 56 kg/ha N rates under both tillage situations

Alien Registration- Lyle, John W. (Bangor, Penobscot County)

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Someday We\u27ll Be Happy

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