2,626 research outputs found

    Design of hydraulic output Stirling engine

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    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency

    Optimization of Adaptation - A Multi-objective Approach for Optimizing Changes to Design Parameters

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    Dynamic optimization problems require constant tracking of the optimum. A solution for such a problem has to be adjustable in order to remain optimal as the optimum changes. The manner of changing design parameters to predefined values is dealt with in the field of control. Common control approaches do not consider the optimality of the design, in terms of the objective function, while adjusting to the new solution. This study highlights the issue of the optimality of adaptation, and defines a new optimization problem – ”Optimization of Adaptation”. It is a multiobjective problem that considers the cost of the adaptation and the optimality while the adaptation takes place. An evolutionary algorithm is proposed in order to solve this problem, and it is demonstrated, first, with an academic example, and then with a real life application of a robotic arm control

    Design of Miniaturized Narrowband Absorbers Based on Resonant-Magnetic Inclusions

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    Cataloged from PDF version of article.In this paper, we present the design of miniaturized narrowband-microwave absorbers based on different kinds of magnetic inclusions. The operation of the proposed components originates from the resonance of a planar array of inclusions excited by an incoming wave with a given polarization. As in common absorber layouts, a 377 Omega resistive sheet is also used to absorb the electromagnetic energy of the impinging field. Since the planar array of magnetic inclusions behaves at its resonance as a perfect magnetic conductor, the resistive sheet is placed in close proximity of the resonating inclusions, without perturbing their resonance condition. In contrast to other typical absorber configurations presented in the literature, the absorber proposed in this paper is not backed by a metallic plate. This feature may be useful for stealth applications, as discussed thoroughly in the paper. The other interesting characteristic of the proposed absorbers is the subwavelength thickness, which has shown to depend only on the geometry of the basic resonant inclusions employed. At first, regular split-ring resonators (SSRs) disposed in an array configuration are considered and some application examples are presented. Absorbers based on SRRs are shown to reach thickness of the order of lambda(0)/20. In order to further squeeze the electrical thickness of the absorbers, multiple SRRs and spiral resonators are also used. The employment of such inclusions leads to the design of extremely thin microwave absorbers, whose thickness may even be close to lambda(0)/100. Finally, some examples of miniaturized absorbers suitable for a practical realization are proposed

    Static quantities of a neutral bilepton in the 331 model with right-handed neutrinos

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    A neutral vector boson can possess static electromagnetic properties provided that the associated field is no self-conjugate. This possibility is explored in the SUC(3)XSUL(3)XUN(1)SU_C(3) X SU_L(3) X U_N(1) model with right-handed neutrinos, which predicts a complex neutral gauge boson Y0Y^0 in a nontrivial representation of the electroweak group. In this model the only nonvanishing form factors are the CP-even ones, which arise from both the quark and gauge sectors, and contribute to the magnetic dipole and the electric quadrupole moments of this neutral particle.Comment: 10 pages, 6 figures, submitted to Phys. Rev.

    Life cycle assessment of protected strawberry productions in central Italy

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    Agricultural activities in Europe cover half of the total area of the continent and are simultaneously a cause of environmental impact and victims of the same impact. Horticultural or fruit crops are considered highly intensive and often employ many crop inputs such as fertilizers, pesticides, and various materials. Strawberry falls into this group, and it has grown in acreage and production more than others globally. The aim of this study is to compare the environmental impact of two strawberry cultivation systems in central Italy, a mulched soil tunnel and a soilless tunnel system. The method used to assess the impact is LCA, widely applied in agriculture and supported by international standards. The data used are mainly primary, related to 2018, and representative of the cultivation systems of central Italy. For impact assessment, the method selected was the CML_IA baseline version. From the results obtained, the two systems show a similar impact per kg of strawberries produced (e.g., for global warming: 0.785 kg CO2 eq for soilless, 0.778 kg CO2 eq for mulched soil tunnel). Reduced differences can be observed for the use of crop inputs (greater for the tunnel) and the use of materials and technology (greater for soilless). The mitigation measures considered concern the replacement of the packaging (excluding plastic) and the growing medium of the soilless using perlite and compost from insect breeding

    The Impact of the Semente Program on the Family-Focused Practice of Mental Health Professionals in Portugal.

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    Background: Children of parents with mental illness (COPMI) are a high-risk group. There is a strong association between parents' psychiatric disorders and the incidence of psychopathology in their children. These children need to be identified and supported by mental health workers early, and hence, clinical practice in adult mental health services needs to change from a focus on individual patients to a more systemic family focus. "Semente," a mental health promotion program developed by the Psychiatry Service of Fernando Fonseca hospital (Lisbon, Portugal), had been established to identify these children and families and promote their mental health, by decreasing the impact of risk factors and promoting protective factors. The program included preventive COPMI interventions and implementation of activities offered to families with children in the mental health care. The aim of the present study was to evaluate changes in mental health care after the training in "Child Talks" intervention (two to three psycho-educational meetings with parents and children) and implementation of the "Semente" program. Methods: Participants (N = 51) were all professionals from Psychiatric Service of Fernando Fonseca Hospital who received Child Talks training. The Family-Focused Mental Health Practice Questionnaire (FFMPQ) was used to measure change in professionals' attitudes, knowledge, confidence, and organizational structure in working with these families. All participants filled in the questionnaire before training and 10 months later. Results: The results showed that, from pre- to post-measurement, the professionals changed clinical practice significantly. The largest changes were visible in the improved provision of support at the workplace for family-focused practice and the clarity and availability of the policies and procedures. Furthermore, the skill and knowledge of the mental health workers showed significant improvement at posttest. Conclusion: The positive results of this study were not unexpected; the training, implementation of routines, and procedures as well as workplace support were aims of the "Semente" program. Interpretation of the results should be taken with caution because of the small sample and the lower reliability of some of scales of the FFMPQ. The results indicate that professionals moved from patient focus to family focus during the implementation of the "Semente" program.info:eu-repo/semantics/publishedVersio

    Removal and fate of pesticides in a farm constructed wetland for agricultural drainage water treatment under Mediterranean conditions (Italy)

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    A non-waterproofed surface flow constructed wetland (SFCW), treating agricultural drainage water in Northern Italy, was investigated to gain information on the potential ability for effective pesticide abatement. A mixture of insecticide imidacloprid, fungicide dimethomorph, and herbicide glyphosate was applied, by simulating a single rain event, into 470-m-long water course of the SFCW meanders. The pesticides were monitored in the wetland water and soil for about 2 months after treatment. Even though the distribution of pesticides in the wetland was not uniform, for each of them, a mean dissipation of 50% of the applied amount was already observed at ≤7 days. The dissipation trend in the water phase of the wetland fitted (r2 ≥ 0.8166) the first-order model with calculated DT50 of 20.6, 12.0, 5.8, and 36.7 days for imidacloprid, dimethomorph, glyphosate, and the glyphosate metabolite AMPA, respectively. The pesticide behavior was interpreted based on the chemical and physical characteristics of both the substances and the water-soil system. Despite the fast abatement of glyphosate, traces were detected in the water until the end of the trial. The formation of soluble 1:1 complex between glyphosate and calcium, the most representative cation in the wetland water, was highlighted by infrared analyses. Such a soluble complex was supposed to keep traces of the herbicide in solution
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