The plasmatron: Advanced mode thermionic energy conversion

A theory of the plasmatron was developed. Also, a wide range of measurements were obtained with two versatile, research devices. To gain insight into plasmatron performance, the experimental results are compared with calculations based on the theoretical model of plasmatron operation. Results are presented which show that the plasma arc drop of the conventional arc (ignited) mode converter can be suppressed by use of an auxiliary ion source. The improved performance, however, is presently limited to low current densities because of voltage losses due to plasma resistance. This resistance loss could be suppressed by an increase in the plasma electron temperature or a decrease in spacing. Plasmatron performance characteristics for both argon and cesium are reported. The argon plasmatron has superior performance. Results are also presented for magnetic cutoff effects and for current distributing effects. These are shown to be important factors for the design of practical devices

AN APPLICATION OF SAFETY-FIRST PROBABILITY LIMITS IN A DISCRETE STOCHASTIC FARM MANAGEMENT PROGRAMMING MODEL

A sequential decision-making model was developed, and data from farm-raised catfish production were used to demonstrate its use. Outcomes of sequences of decisions which satisfied chance constraints on ending cash balances were traced through a specified time period. Discrete choice variables were specified due to the fixed nature of pond facilities. Recourse actions specified were sale of production in excess of endogenously determined transfer levels or purchase of inputs to supplement needs of the next production stage. Production activities cannot be changed during the planning period. Only yield variability was considered due to its impact on relative competitiveness among growth stages. Deviations were calculated from endogenously determined target levels based on goal and probability limits.Farm Management,

ENDOGENOUS GROWTH MODELS AND THE ENVIRONMENTAL KUZNETS CURVE: AN ANALYSIS OF GLOBAL ENVIRONMENTAL SUSTAINABILITY

Fertilizer consumption per cubic meter of freshwater is taken as a proxy for global water quality indicator. A global model of environmental quality for 121 countries confirms the Kuznet's hypothesis. Global turning point is reached at nearly five times the average income of all countries. Foreign Direct Investment (FDI) was significant to increase the national income. Increased aid and larger farm size per capita favored higher environmental quality, albeit insignificant. A flow of better technology and possible non-agricultural employment might help improve water quality in developing countries when their net income increases.Environmental Economics and Policy,

CHANGE AND CONFLICT IN LAND AND WATER USE: RESOURCE VALUATION IN CONFLICT RESOLUTION AMONG COMPETING USERS

Resource /Energy Economics and Policy,

SOCIOECONOMIC INFLUENCES ON LAND USE CHOICE AT WATERSHED LEVEL: A MULTINOMIAL LOGIT ANALYSIS OF LAND USE DISTRIBUTION IN WEST GEORGIA

Allocation of fixed proportion of land to developed, forest, agricultural and other land uses in a watershed was modeled as an optimization problem faced by a single user. A multinomial logit model was used to estimate the effects of urbanization, demographic structure, personal income and spatial distribution of watersheds.Land Economics/Use,

RELATING FARM AND OPERATOR CHARACTERISTICS TO MULTIPLE GOALS

Farm Management,

Association of prior depressive symptoms and suicide attempts with subsequent victimisation - analysis of population-based data from the Adult Psychiatric Morbidity Survey

Background: Symptoms of mental disorder, particularly schizophrenia, predispose to victimisation. Much less is known about the relationship between depressive symptoms and later victimisation in the general population, the influence of these symptoms on types of subsequent victimisation, or the role of symptom severity. We investigated this in nationally representative data from the UK. Methods: Data were from the Adult Psychiatric Morbidity Survey 2007. Multivariable logistic regressions estimated association between: a. prior depressive symptoms, and b. prior depressive symptoms with suicide attempt, and types of more recent victimisation. Gender-specific associations were estimated using multiplicative interactions. Results: Prior depressive symptoms were associated with greater odds of any recent intimate partner violence (IPV), emotional IPV, sexual victimisation, workplace victimisation, any victimisation, and cumulative victimisation (adjusted odds ratio (aOR) for increasing types of recent victimisation: 1.47, 95% confidence interval (CI): 1.14, 1.89). Prior depressive symptoms with suicide attempt were associated with any recent IPV, emotional IPV, any victimisation, and cumulative victimisation (aOR for increasing types of recent victimisation: 2.33, 95%: 1.22, 4.44). Limitations: Self-reported recalled data on previous depressive symptoms, may have limited accuracy. Small numbers of outcomes for some comparisons resulted in imprecision of these estimates. Conclusion: Aside from severe mental illness such as schizophrenia, previous depressive symptoms in the general population are associated with greater subsequent victimisation. Men and women with prior depressive symptoms may be vulnerable to a range of types of victimisation, and may benefit from interventions to reduce this vulnerability

COASTAL ALABAMA RECREATIONAL LIVE BAIT STUDY

Recreational fishing is major industry and reasonably priced, high quality bait plays an important role in sustaining recreational fishing's popularity. This study provides a summary of Alabama's coastal live bait market including information on previous live bait studies and results of two surveys on the live bait shrimp, bull minnow and other bait markets. Results indicated there were periods of supply shortages, dealer willingness to pay more for shrimp that live longer and a dealers' use of multiple supply sources. Lost income was reported from not having live bait shrimp available for sale at peak demand periods. The economics of shrimp mariculture needs to be examined to determine its feasibility in augmenting the current supply of shrimp to the live bait industry.Resource /Energy Economics and Policy,

OPTIMAL IRRIGATION PIVOT LOCATION ON IRREGULARLY SHAPED FIELDS

Although annual rainfall in the Southeast is adequate, its distribution is a potential constraint to agricultural production. Farmers require production information concerning efficient use of irrigation technology adapted to regional growing conditions. Selection of optimal position, size, and number of pivots in center pivot irrigation systems poses special problems on small, irregularly shaped fields. In the southeastern United States, field size and shape are often varied and irregular. A mixed integer programming model was constructed to assist in irrigation investment decisions. The model is illustrated using irrigated peanut production in southeast Alabama. Results indicate the importance of economic engineering considerations.Farm Management,

An Investigation of the Socioeconomic Impacts of Tri-State Bypass, 1970-2000

Geographical information systems and econometric tools were used to determine the socioeconomic impacts of bypasses in Atlanta-Birmingham Metropolitan area. Mean household income and per capita income of county is separately used as a proxy for anticipated bypass impact as a function, of socioeconomic variables: farm income, farm employment, non-farm employment, age groups, and population density. The cross-sectional and the time series data were pooled together and estimated as panel data. Results indicate that most of these variables have positive impacts on growth.Public Economics,