Search

Comparison of organic apricot production under all-season rain protection, seasonal rain protection and without rain protection.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 2184-2190, PV systems using bifacial solar modules have shown an increased energy harvest compared to systems with standard, monofacial panels. Due to bifaciality of the modules, the tilt angle, the installation height, the distance between the modules and in particular the ground reflectance have a significant influence on the energy harvest. For bifacial module arrays reflective elements in between the rows might be an option in order to achieve a low light concentration resulting in a further increased energy harvest. A simulation of such conditions is hardly possible; measurements at real systems would require considerable effort. In this work we present results obtained by a measuring setup with rotating mini modules. In particular the influence of the ground reflection was studied by using various grounds and reflecting elements with different shapes. Prior to the analysis of the reflector elements the measurement setup is described and the assignability of results from the miniaturized test array to a corresponding large scale system is demonstrated.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 1618-1622, The common assumption is that plants underneath PV modules will cause a cooling effect resulting in a higher energy yield due to the negative temperature coefficient of PV power. The PV module temperature is measured to verify this thesis on a flat roof PV plant in Winterthur, Switzerland. Thirteen different mounting test field types with two different mechanical PV mounting systems are used, 20° or 15° tilted angles. Each type of mechanical mounting system is combined with planting beneath and with and without irrigation in the different test fields. The difference of the module temperatures, weighted according to the energy production, of all 13 analysed test fields is between ± 1.8 °C. This temperature difference results in a calculated energy yield difference of about ± 0.7 % for the used crystalline silicon modules. This value is in the range of the measurement uncertainty of the power measurement (± 1.2 %). Therefore the green roof has only negligible influence on the temperature reduction of the PV modules on the base of the used system components. However, a combination of PV and green roof is absolutely doable and recommendable provided that the mounting system is optimized for green roofs. Other more powerful benefits of such combination of green roofs and PV are the improvement of water retention in the city.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3105-3109, This paper provides an overview of the prEN 50530, the upcoming European Standard for measuring the overall efficiency of PV inverters. It explains in depth the approach and methodology introduced in the standard for a combined assessment of the conversion as well as the Maximum Power Point tracking efficiency. In addition, a background insight on the test conditions, the necessary test equipment and interpretation of the results is provided.

Injuries to the central venous system can result from penetrating trauma or iatrogenic causes. Injuries to major venous confluences can be particularly problematic, because the clavicle and sternum seriously limit exposure of the injury site. We report our institution's experience with central venous injuries of the subclavian-jugular and innominate-caval venous confluences. Significant injuries of the subclavian-jugular venous confluence frequently result from penetrating trauma, while injuries to the innominate-caval confluence are usually catheter-related. Median sternotomy provides adequate exposure of the innominate-caval confluence, while exposure of the subclavian-jugular venous confluence requires extension of the median sternotomy incision into the neck and resection of the clavicle. The literature is reviewed.

This article describes the use of a flexible bronchoscope to remove pledgetted repair sutures within the trachea. The use of a flexible scope to remove densely adherent material is difficult but occasionally necessary.

Patients with severe ventricular dysfunction make up a special subset of patients who undergo coronary artery bypass procedures. For these patients, the risk associated with the bypass procedure is relatively high, but the opportunity-for-survival benefit is also greater. We studied 61 consecutive coronary artery bypass patients with preoperative ejection fractions < or = 25%, and further compared several subgroups: Group I (n = 30) ejection fractions ranged from 21% to 25%; Group II (n = 23) ejection fractions ranged from 16% to 20.9%; and Group III (n = 8) ejection fractions ranged from 10% to 15.9%. The overall mortality rate was 8% (5/61), with no deaths in Group III. The 41% (25/61) of patients who received left internal mammary artery conduits experienced a higher mortality rate, yet it did not differ significantly from that of patients who received only saphenous vein conduits. Intraaortic balloon pumps were placed in 48% (29/61) of the patients, with a progressively higher incidence in patients with poorer ventricular function (P < 0.05). Most intraaortic balloon pumps (59%) were placed intraoperatively. Two patients underwent placement of left ventricular assist devices, and 1 of these survived. Coronary artery bypass grafting in patients with poor ventricular function carries a substantial, but acceptable, mortality risk. Use of the left internal mammary artery did not improve perioperative mortality, and may have a negative impact in the early postoperative period. Intraaortic balloon pump use was most common in those patients with the worst ventricular function. Prophylactic intraaortic balloon pump use may be justified in candidates with ejection fractions < 20%.