Simulación de sistemas de riego hibridos FV-RED: aplicación a riego directo

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: Este artículo presenta la metodología utilizada en una herramienta de simulación de la productividad de sistemas de riego híbridos fotovoltaico-red, así como su aplicación a un sistema de riego directo en Marrakech, Marruecos. Se trata de una finca de olivar intensivo, cuyas necesidades de riego son 8 horas diarias entre marzo y octubre. La aportación fotovoltaica en ese periodo es de 1456 kWh/kWp, mientras que la red eléctrica tiene que aportar 66 kWh/kWp. Entre los meses de noviembre y febrero toda la energía fotovoltaica es desaprovechada (550 kWh/kWp) puesto que no se riega. Con el objetivo de generalizar el estudio, se analiza la influencia de las necesidades de riego diarias en la aportación FV mediante cuatro simulaciones adicionales para necesidades de riego diarias de 4 h, 10 h, 12 h y 16 h. Por ejemplo, en el mes de junio, y considerando 4 h de riego al día, la aportación FV es 104 kWh/kWp (cuando para las 8 h es 185 kWh/kWp), llegando a 239 kWh/kWp a partir de las 12 h de riego al día.ABSTRACT: This article explains the methodology used in a hybrid photovoltaic-grid irrigation system simulation tool, as well its application to a direct pumping system in Marrakech, Morocco. It is an intensive olive tree cultivation, with a daily irrigation need of 8 hours between March and October. The photovoltaic energy used in this period is 1456 kWh/kWp, while the grid electricity consumption is 66 kWh/kWp. Between November and February, the photovoltaic energy is wasted (550 kWh/kWp). To evaluate the influence of the irrigation needs in terms of the number of irrigation hours per day, four additional simulations were performed – for 4 h, 10 h, 12 h, and 16 h. For example, in June, and considering 4 h of irrigation per day, the photovoltaic energy used is 104 kWh/kWp (while it is 185 kWh/kWp for 8 hours), achieving 239 kWh/kWp from 12 hours of irrigation per day.info:eu-repo/semantics/publishedVersio

Efecto de la osteotomía medializante de calcáneo sobre tejidos blandos de soporte del arco plantar: un estudio computacional

Medializing calcaneal osteotomy forms part of the treatment options for adult acquired flat foot. The structural correction that is achieved is widely known. However, the effect of this procedure on the soft tissues that support the plantar arch has been little studied, since it is not possible to quantify experimentally the tension and deformation variations generated. Therefore, the objective of this study was to evaluate the effect of medializing calcaneal osteotomy on the soft tissue that supports the plantar arch, using a computational model of the human foot designed with a clinical approach. The proposed finite element model was reconstructed from computerized tomography images of a healthy patient. All the bones of the foot, the plantar fascia, cartilages, plantar ligaments and the calcaneus-navicular ligament were included, respecting their anatomical distribution and biomechanical properties. Simulations were performed emulating the monopodal support phase of the human walk of an adult. The effect on each tissue was evaluated according to clinical and biomechanical criteria. The results show that calcaneal osteotomy reduces the tension normally generated on the evaluated tissues, with the effect on the calcaneus-navicular ligament and the plantar fascia being the most notable. The deformation results obtained are consistent with experimental tests and clinical knowledge. The versatility of this model allows the objective assessment of different conditions and supports decision making for the treatment of adult acquired flat foot in middle and advanced stages

Changes in Coastal Benthic Algae Succession Trajectories and Assemblages Under Contrasting Nutrient and Grazer Loads

Eutrophication plays a crucial role in coastal systems, driving changes in the composition and abundance of flora and fauna with consequent effects for the entire ecosystem. Sensitive to nutrient levels, micro- and macroalgal blooms serve as valuable indicators of eutrophication. The San Antonio Bay (Northern Argentinean Patagonia, 40° 43′ S, 64° 56′ W) provides an appropriate system to study in situ eutrophication processes on coastal communities. In a multi-scale approach, using two different kind of settlement substrates (micro: polyethylene terephthalate, and macro: ceramic), the present study followed benthic algal dynamics over one year, distinguishing changes in natural succession and seasonality. Strong differences were found in the biofilm assemblages after three days, marked by tube dwelling diatoms and Cocconeis spp. under high nutrient-grazer conditions and needle like diatoms (e.g. Nitzschia spp., Tabularia spp.) under lower nutrient-grazer loads. The succession continued by the colonization of macroalgae, with a higher recruitment rate in the nutrient and grazer rich environment with a concomitant higher diversity. Our results show that under higher nutrient-grazer conditions natural benthic succession not only differs in trajectory but in its final taxa composition promoting higher biodiversity and biomass accumulation. In addition, taxa specific substrate preferences interfere with the observed eutrophication pattern, suggesting substrate dependant interrelations between the bloom forming taxa. These findings provide evidence that nutrient enrichment can not only affect an established assemblage but also affect the early succession stages, changing the succession trajectory and thus the final assemblage.Facultad de Ciencias Naturales y Muse

Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms

Canagliflozin and Renal Outcomes in Type 2 Diabetes and Nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to 300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m 2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to &lt;90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], &gt;300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of &lt;15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P&lt;0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P&lt;0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Evaluación del performance de un sistema de riego FV de alta potencia tras 2 años de operación

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: Los sistemas de riego de alta potencia alimentados a través de la red eléctrica o generadores diésel van dando paso a sistemas fotovoltaicos (FV) de alta potencia que reducen el coste de la energía hasta en un 80%. Se trata de una tecnología nueva de la que se desconocen los datos de performance esperables y su comportamiento frente a la variabilidad de la potencia FV provocada por el paso de nube. Este artículo recupera la definición de unos nuevos índices de performance y presenta sus valores experimentales para un sistema de riego FV de 360 kWp a balsa, aislado de la red y sin baterías, así como los valores del índice de resistencia al paso de nube. El rendimineto del sistema ha sido analizado a lo largo de dos años de operación real del mismo. Por ejemplo, el performance ratio de la parte FV, PRPV, fue de un 79,6% y 80,3% en el primer y segundo año de operación, respectivamente, y el índice de resistencia al paso de nube fue del 95,6%.ABSTRACT: High-power diesel-based or grid-connected irrigation systems are giving way to high-power photovoltaic (PV) systems that reduce the energy costs by up to 80%. This is a new technology for which the expected performance data and its behavior against the variability of PV power caused by passing clouds are unknown. This paper incorporates the existing definition of new performance ratios and presents their experimental values for a stand-alone and battery-free 360 kWp irrigation system, pumping to a water pool, as well as the values for the passing cloud resistance ratio. The system’s performance has been analyzed over two years of real operation. For example, the performance ratio of the PV part, PRPV, was 79,6% and 80,3% in the first and second year of operation, respectively, and the passing cloud resistance ratio was 95,6%.info:eu-repo/semantics/publishedVersio

Saharan dust transport to Europe and its impact on photovoltaic performance: A case study of soiling in Portugal

Abstract The impact of long range Saharan dust transport, arising from one event in February and other in March 2017, on the performance of photovoltaic flat panels is reported as a case study of soiling. Through satellite images, dust coming from north Africa was detected, while using the Hybrid Single-Particle Lagrangian Integrated Trajectory, specific origin locations of the dust were found. Dust accumulated on glass coupons deployed in Southern Portugal, Évora and Alter do Chão, was analysed by Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy. Mass accumulation on those coupons was weekly measured with a microbalance and related with environmental parameters, aerosol optical depth and rain, through a proposed empirical model. Performance measurement took place at Évora using mc-Si PV flat panels and an I-V curve tracer to get two parameters: maximum output power and short-circuit current. It was found that the first dust event led to decreases in the maximum output power of ≈8% and in the short-circuit current of ≈3%, while the second event led to a decrease of ≈3% in both parameters. A relation between PV performance and mass accumulation was successfully explored