Elliptical Combing Motion for Harvesting Bell Peppers

A new concept for mechanically harvesting bell peppers, intended specifically for multiple-pass harvesting, utilized spaced horizontal fingers combing vertically upward through plant foliage in an elliptical path alternating from both sides of the row. An apparatus based on this concept was designed and built, and harvest tests were conducted to determine the effect of two main machine operating parameters, vertical picking speed and disk angle. Harvesting performance was evaluated in terms of harvest efficiency, fruit damage, and plant damage as it related to multiple-pass harvesting. Fruit removal, both harvestable size and immature, increased significantly as vertical picking speed increased. Branch breakage also tended to increase as vertical picking speed increased, partially accounting for the increased fruit removal. Fruit damage increased significantly as the disk angle increased. Overall, the average harvest efficiency for the tests was 81% and the average fruit damage was 5.9%

Determination of Strategy for Harvesting Burley Tobacco

The decision-making process associated with the scheduling of burley tobacco harvesting operations was formulated as a multi-stage decision process, and solved using a procedure called dynamic programming. The solution of a stochastic dynamic programming model provides a set of optimal decision rules, that is, a strategy. When certain user-specified parameters are provided, the decision model provides information concerning the optimal date to start harvesting, the optimal number of hours to harvest on each day, the optimal date to introduce hired labor, and the optimal number of workers which should be hired. The solution of the dynamic programming model makes it possible to compute a timeliness cost which is defined as the amount of the expected total return which is lost because of delaying harvest initiation beyond the optimal starting day. Thus, a decision-maker can consult tabulated strategy solutions in any situation during the harvesting season and make decisions with the aid of timeliness cost information

A Computer Model for Analysis of Alternative Burley Tobacco Harvesting Practice

Agricultural operations and practices have been the subject of many computer models and simulations. Holtman et al. (1970) developed a corn harvesting simulator, and Morey et al. (1971) used simulation techniques to analyze net profit of a corn harvesting and handling system during a particular weather year. Further, Loewer et al. (1977) advanced a model that assessed alternative beef production strategies for the individual farm with land, energy and capital as constraints. Bridges et al., (1979) developed a design simulation oriented toward the individual producer that examines corn harvesting systems and compares them regarding investment and annual cost. The CATCH (Computer Analysis of Tobacco Cutting and Housing) simulation model (Bridges et al., 1980) was written to apply similar principles to the analysis of burley tobacco systems

Economic Comparison of Alternative Burley Tobacco Harvesting Practices by Computer

The computer model CATCH (Computer Analysis of Tobacco Cutting and Housing) was developed to provide the individual tobacco producer with management information concerning alternative methods of harvesting burley tobacco. CATCH utilizes specific producer in-puts to analyze 24 alternative burley production systems and presents up to four economic rankings containing costs, equipment and labor for each system. The economic rankings aid the producer in decision making with regard to his own operation

Simulation of Burley Tobacco Harvesting-Housing Systems

A computer model has been developed using systems analysis techniques to simulate the labor and equipment aspects of harvesting burley tobacco. By varying the parameters of the model the user can determine a harvesting and housing strategy based on labor and equipment availability

A Reduced–Cost Mechanized System for Handling and Curing Mechanically–Harvested Burley Tobacco

An experimental system was tested in which mechanically harvested burley tobacco plants placed onto steel slotted receivers were retrieved from a field, transported to a field curing structure, and placed onto the structure for air curing by a single worker. The system consisted of a tractor–towed, trailer mechanism that engaged and hoisted loads of approximately 360 burley plants of approximately 1 Mg mass. Ten slotted steel rails, 3.05 m long, holding 36 notched plants were placed onto parallel wooden beams suspended at a height of 2.13 m by wooden posts set in the ground. Burley tobacco was cured in this configuration covered by polyethylene. Time–and–motion experiments showed that the system could retrieve tobacco from the field and place it onto a curing structure adjacent to the field at the rate of 0.1 to 0.18 ha/h. Replicated experiments also showed that the system operated with negligible leaf loss due to handling. Finally, experimental results showed that leaf grade index decreased with time that filled tobacco rails were left lying on the ground after being harvested and prior to being retrieved. This study further indicated that the estimated cost of the proposed harvesting system compares favorably with systems that require several manual laborers

Policy-driven, narrative-based evidence-gathering: UK priorities for decarbonisation through biomass

Evidence-based policy-making (EBPM) has been a much-debated concept, attracting various theoretical interpretations. This paper builds on those insights for a novel perspective: policy-driven, narrative-based evidence-gathering. In a case study of UK priority-setting for bioenergy innovation, documents and interviews were analysed to identify links between problem-diagnoses, societal visions, policy narratives and evidence-gathering. This process is illuminated by the theoretical concept of socio-technical imaginaries – technoscientific projects which the state should promote for a feasible, desirable future. Results suggest that evidence has been selectively generated and gathered within a specific future vision, whereby bioenergy largely provides an input-substitute within the incumbent centralised infrastructure; such evidence is attributed to an external expertise, thus helping to legitimise the policy framework. Evidence has helped to substantiate policy commitments to expand bioenergy. An earlier policy vision for decentralised bioenergy has been kept marginal. The dominant narrative has been reinforced by the government’s multi-stakeholder consultation favouring incumbent industry and by incentive structures for industry co-investment

A High Power Hydrogen Target for Parity Violation Experiments

Parity-violating electron scattering measurements on hydrogen and deuterium, such as those underway at the Bates and CEBAF laboratories, require luminosities exceeding $10^{38}$cm$^{-2}$s$^{-1}$, resulting in large beam power deposition into cryogenic liquid. Such targets must be able to absorb 500 watts or more with minimal change in target density. A 40~cm long liquid hydrogen target, designed to absorb 500~watts of beam power without boiling, has been developed for the SAMPLE experiment at Bates. In recent tests with 40~$\mu$A of incident beam, no evidence was seen for density fluctuations in the target, at a sensitivity level of better than 1\%. A summary of the target design and operational experience will be presented.Comment: 13 pages, 9 postscript figure