The elective treatment of a spigelian hernia is still under discussion, fundamentally owing to its rarity. The purpose of the study is to analyze the elective surgical treatment of spigelian hernia.Design: A prospective, randomized controlled trial.Setting: University teaching hospital.Patients and Interventions: Two surgeons performed 11 conventional and 11 laparoscopic repairs for a spigelian hernia, alternating roles as primary surgeon and assistant. Each time the type of technique was randomly chosen using a computerized program.Main Outcome Measures: Epidemiological, clinical, and surgical factors are analyzed according to treatment, ie, the open or laparoscopic approach.Results: The statistical study shows no significant differences for epidemiological or diagnostic factors, but it does show significant advantages for laparoscopy in terms of morbidity (PϽ.05) and hospital stay (PϽ.001).
Conclusion:The approach using extraperitoneal laparoscopy is the technique that offers best results in the elective treatment of spigelian hernia.
The adaptation of the mature PV water-pumping technology to large power irrigation applications requires the problems associated to PV power intermittencies and matching PV production with the irrigation needs to be resolved. This paper presents the innovations developed, implemented and tested in a PV irrigation prototype installed in a real well at an Irrigator Community in Alicante, Spain. The innovations elimínate the intermittences due to passing clouds, reducing the PV power by 80% in just few seconds without batteries, just using control algorithms in the frequency converter, avoiding water hammers and overvoltages. A North-South horizontal axis tracker has been used to extend the number of hours of irrigation per day and to provide daily constant profiles of PV power during the irrigation period. Moreover, the use of this tracker allows the nominal power of the PV generator to be reduced by 45% as compared to a flxed structure for the same volume of water. The analysis of the economic feasibility of the prototype compared with the cost of grid electricity shows savings of 60%. This prototype has been operating in the South of Morocco delivering more than 235 m 3 /day for the last three years.
This paper presents an economic assessment of large power (from tens to hundreds kWp) PV irrigation systems in the ECOWAS region, evaluating the economic feasibility of substituting diesel-powered and grid-powered systems with PV ones. Seven countries from the ECOWAS region were considered and two irrigation operating modes were compared (pumping to a water tank or at constant pressure). Net Present Cost (NPC) values are in the 0.33-41.5x10 5 $ range, Internal Rate of Return (IRR) values are in the 8-47% range and Payback Period (PBP) values are in the 2.1-10 years range. The economic savings in terms of Levelized Cost of Energy, LCOE, were also evaluated. LCOE for PV irrigation systems are in the 4.5-17.4 $cents/kWh range, which represent percentage savings of 30-84% if compared to diesel-powered and gridpowered systems.
In decentralised rural electrification through solar home systems, private companies and promoting institutions are faced with the problem of deploying maintenance structures to operate and guarantee the service of the solar systems for long periods (ten years or more). The problems linked to decentralisation, such as the dispersion of dwellings, difficult access and maintenance needs, makes it an arduous task. This paper proposes an innovative design tool created ad hoc for photovoltaic rural electrification based on a real photovoltaic rural electrification program in Morocco as a special case study. The tool is developed from a mathematical model comprising a set of decision variables (location, transport, etc.) that must meet certain constraints and whose optimisation criterion is the minimum cost of the operation and maintenance activity assuming an established quality of service. The main output of the model is the overall cost of the maintenance structure. The best location for the local maintenance headquarters and warehouses in a given region is established, as are the number of maintenance technicians and vehicles required.
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