Review of the Performance of Residential PV systems in France

The main objective of this paper is to review the state of the art of residential PV systems in France. This is done analyzing the operational data of 6868 installations. Three main questions are posed. How much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? During the year 2010, the PV systems in France have produced a mean annual energy of 1163 kWh/kWp. As a whole, the orientation of PV generators causes energy productions to be some 7% inferior to optimally oriented PV systems. The mean Performance Ratio is 76% and the mean Performance Index is 85%. That is to say, the energy produced by a typical PV system in France is 15% inferior to the energy produced by a very high quality PV system. On average, the real power of the PV modules falls 4.9% below its corresponding nominal power announced on the manufacturer's datasheet. A brief analysis by PV modules technology has led to relevant observations about two technologies in particular. On the one hand, the PV systems equipped with heterojunction with intrinsic thin layer (HIT) modules show performances higher than average. On the other hand, the systems equipped with the copper indium (di)selenide (CIS) modules show a real power that is 16% lower than their nominal value.

Performance Analysis of 10,000 Residential PV Systems in France and Belgium

The main objective of this paper is to review the state of the art of residential PV systems in France and Belgium. This is done analyzing the operational data of 10650 PV systems (9657 located in France and 993 in Belgium). Three main questions are posed. How much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? During the year 2010, the PV systems in France have produced a mean annual energy of 1163 kWh/kWp in France and 852 kWh/kWp in Belgium. As a whole, the orientation of PV generators causes energy productions to be some 7% inferior to optimally oriented PV systems. The mean Performance Ratio is 76% in France and 78% in Belgium, and the mean Performance Index is 85% in both countries. On average, the real power of the PV modules falls 4.9% below its corresponding nominal power announced on the manufacturer?s datasheet. A brief analysis by PV modules technology has lead to relevant observations about two technologies in particular. On the one hand, the PV systems equipped with Heterojunction with Intrinsic. Thin layer (HIT) modules show performances higher than average. On the other hand, the systems equipped with Copper Indium (di)Selenide (CIS) modules show a real power that is 16 % lower than their nominal value.

Non uniform target illumination in deflagration regime : refractive smoothing

Refractive smoothing of weak non-uniformities in the illumination of laser targets is analyzed, assuming absorption at the critical density and restricting conduction to a thin layer, and using results from thermal smoothing, which is uncoupled from the refraction. Magnetic effects are included. Non-uniformity wavelengths comparable to the thickness of the conduction layer are considered; efficient smoothing exists at both short and long wavelengths in this range. Thermal focusing could make the ablated plasma unstable.

Magnetic self-field effects on current collection by an ionospheric bare tether

It was recently suggested that the magnetic field created by the current of a bare tether strongly reduces its own electron-collection capability when a magnetic separatrix disconnecting ambient magnetized plasma from tether extends beyond its electric sheath. It is here shown that current reduction by the self-field depends on the ratio meterizing bias and current profiles along the tether (Lt tether length, characteristic length gauging ohmic effects) and on a new dimensionless number Ks involving ambient and tether parameters. Current reduction is weaker the lower Ks and L*/ Lt, which depend critically on the type of cross section: Ks varies as R5/3, h2/3R, and h2/3 1/4 width for wires, round tethers conductive only in a thin layer, and thin tapes, respectively; L* varies as R2/3 for wires and as h2/3 for tapes and round tethers conductive in a layer (R radius, h thickness). Self-field effects are fully negligible for the last two types of cross sections whatever the mode of operation. In practical efficient tether systems having L*/Lt low, maximum current reduction in case of wires is again negligible for power generation; for deorbiting, reduction is <1% for a 10 km tether and 15% for a 20 km tether. In the reboost mode there are no effects for Ks below some threshold; moderate effects may occur in practical but heavy reboost-wire systems that need no dedicated solar power.

Sheath vaporization of a monodisperse fuel-spray jet

The group vaporization of a monodisperse fuel-spray jet discharging into a hot coflowing gaseous stream is investigated for steady flow by numerical and asymptotic methods with a two-continua formulation used for the description of the gas and liquid phases. The jet is assumed to be slender and laminar, as occurs when the Reynolds number is moderately large, so that the boundary-layer form of the conservation equations can be employed in the analysis. Two dimensionless parameters are found to control the flow structure, namely the spray dilution parameter 1, defined as the mass of liquid fuel per unit mass of gas in the spray stream, and the group vaporization parameter e, defined as the ratio of the characteristic time of spray evolution due to droplet vaporization to the characteristic diffusion time across the jet. It is observed that, for the small values of e often encountered in applications, vaporization occurs only in a thin layer separating the spray from the outer droplet-free stream. This regime of sheath vaporization, which is controlled by heat conduction, is amenable to a simplified asymptotic description, independent of ε,in which the location of the vaporization layer is determined numerically as a free boundary in a parabolic problem involving matching of the separate solutions in the external streams, with appropriate jump conditions obtained from analysis of the quasi-steady vaporization front. Separate consideration of dilute and dense sprays, corresponding, respectively, to the asymptotic limits λ<<1 and λ>>1, enables simplified descriptions to be obtained for the different flow variables, including explicit analytic expressions for the spray penetration distance.

Entrainment Effects in Turbulent Boundary Layers

Esta tesis estudia el comportamiento de la región exterior de una capa límite turbulenta sin gradientes de presiones. Se ponen a prueba dos teorías relativamente bien establecidas. La teoría de semejanza para la pared supone que en el caso de haber una pared rugosa, el fluido sólo percibe el cambio en la fricción superficial que causa, y otros efectos secundarios quedarán confinados a una zona pegada a la pared. El consenso actual es que dicha teoría es aproximadamente cierta. En el extremo exterior de la capa límite existe una región producida por la interacción entre las estructuras turbulentas y el flujo irrotacional de la corriente libre llamada interfaz turbulenta/no turbulenta. La mayoría de los resultados al respecto sugieren la presencia de fuerzas de cortadura ligeramente más intensa, lo que la hace distinta al resto del flujo turbulento. Las propiedades de esa región probablemente cambien si la velocidad de crecimiento de la capa límite aumenta, algo que puede conseguirse aumentando la fricción en la pared. La rugosidad y la ingestión de masa están entonces relacionadas, y el comportamiento local de la interfaz turbulenta/no turbulenta puede explicar el motivo por el que las capas límite sobre paredes rugosas no se comportan como en el caso de tener paredes lisas precisamente en la zona exterior. Para estudiar las capas límite a números de Reynolds lo suficientemente elevados, se ha desarrollado un nuevo código de alta resolución para la simulación numérica directa de capas límite turbulentas sin gradiente de presión. Dicho código es capaz de simular capas límite en un intervalo de números de Reynolds entre ReT = 100 — 2000 manteniendo una buena escalabilidad hasta los dos millones de hilos en superordenadores de tipo Blue Gene/Q. Se ha guardado especial atención a la generación de condiciones de contorno a la entrada correctas. Los resultados obtenidos están en concordancia con los resultados previos, tanto en el caso de simulaciones como de experimentos. La interfaz turbulenta/no turbulenta de una capa límite se ha analizado usando un valor umbral del módulo de la vorticidad. Dicho umbral se considera un parámetro para analizar cada superficie obtenida de un contorno del módulo de la vorticidad. Se han encontrado dos regímenes distintos en función del umbral escogido con propiedades opuestas, separados por una transición topológica gradual. Las características geométricas de la zona escalan con o99 cuando u^/isdgg es la unidad de vorticidad. Las propiedades del íluido relativas a la posición del contorno de vorticidad han sido analizados para una serie de umbrales utilizando el campo de distancias esféricas, que puede obtenerse con independencia de la complejidad de la superficie de referencia. Las propiedades del fluido a una distancia dada del inerfaz también dependen del umbral de vorticidad, pero tienen características parecidas con independencia del número de Reynolds. La interacción entre la turbulencia y el flujo no turbulento se restringe a una zona muy fina con un espesor del orden de la escala de Kolmogorov local. Hacia el interior del flujo turbulento las propiedades son indistinguibles del resto de la capa límite. Se ha simulado una capa límite sin gradiente de presiones con una fuerza volumétrica cerca de la pared. La el forzado ha sido diseñado para aumentar la fricción en la pared sin introducir ningún efecto geométrico obvio. La simulación consta de dos dominios, un primer dominio más pequeño y a baja resolución que se encarga de generar condiciones de contorno correctas, y un segundo dominio mayor y a alta resolución donde se aplica el forzado. El estudio de los perfiles y los coeficientes de autocorrelación sugieren que los dos casos, el liso y el forzado, no colapsan más allá de la capa logarítmica por la complejidad geométrica de la zona intermitente, y por el hecho que la distancia a la pared no es una longitud característica. Los efectos causados por la geometría de la zona intermitente pueden evitarse utilizando el interfaz como referencia, y la distancia esférica para el análisis de sus propiedades. Las propiedades condicionadas del flujo escalan con 5QQ y u/uT, las dos únicas escalas contenidas en el modelo de semejanza de pared de Townsend, consistente con estos resultados. ABSTRACT This thesis studies the characteristics of the outer region of zero-pressure-gradient turbulent boundary layers at moderate Reynolds numbers. Two relatively established theories are put to test. The wall similarity theory states that with the presence of roughness, turbulent motion is mostly affected by the additional drag caused by the roughness, and that other secondary effects are restricted to a region very close to the wall. The consensus is that this theory is valid, but only as a first approximation. At the edge of the boundary layer there is a thin layer caused by the interaction between the turbulent eddies and the irroational fluid of the free stream, called turbulent/non-turbulent interface. The bulk of results about this layer suggest the presence of some localized shear, with properties that make it distinguishable from the rest of the turbulent flow. The properties of the interface are likely to change if the rate of spread of the turbulent boundary layer is amplified, an effect that is usually achieved by increasing the drag. Roughness and entrainment are therefore linked, and the local features of the turbulent/non-turbulent interface may explain the reason why rough-wall boundary layers deviate from the wall similarity theory precisely far from the wall. To study boundary layers at a higher Reynolds number, a new high-resolution code for the direct numerical simulation of a zero pressure gradient turbulent boundary layers over a flat plate has been developed. This code is able to simulate a wide range of Reynolds numbers from ReT =100 to 2000 while showing a linear weak scaling up to around two million threads in the BG/Q architecture. Special attention has been paid to the generation of proper inflow boundary conditions. The results are in good agreement with existing numerical and experimental data sets. The turbulent/non-turbulent interface of a boundary layer is analyzed by thresholding the vorticity magnitude field. The value of the threshold is considered a parameter in the analysis of the surfaces obtained from isocontours of the vorticity magnitude. Two different regimes for the surface can be distinguished depending on the threshold, with a gradual topological transition across which its geometrical properties change significantly. The width of the transition scales well with oQg when u^/udgg is used as a unit of vorticity. The properties of the flow relative to the position of the vorticity magnitude isocontour are analyzed within the same range of thresholds, using the ball distance field, which can be obtained regardless of the size of the domain and complexity of the interface. The properties of the flow at a given distance to the interface also depend on the threshold, but they are similar regardless of the Reynolds number. The interaction between the turbulent and the non-turbulent flow occurs in a thin layer with a thickness that scales with the Kolmogorov length. Deeper into the turbulent side, the properties are undistinguishable from the rest of the turbulent flow. A zero-pressure-gradient turbulent boundary layer with a volumetric near-wall forcing has been simulated. The forcing has been designed to increase the wall friction without introducing any obvious geometrical effect. The actual simulation is split in two domains, a smaller one in charge of the generation of correct inflow boundary conditions, and a second and larger one where the forcing is applied. The study of the one-point and twopoint statistics suggest that the forced and the smooth cases do not collapse beyond the logarithmic layer may be caused by the geometrical complexity of the intermittent region, and by the fact that the scaling with the wall-normal coordinate is no longer present. The geometrical effects can be avoided using the turbulent/non-turbulent interface as a reference frame, and the minimum distance respect to it. The conditional analysis of the vorticity field with the alternative reference frame recovers the scaling with 5QQ and v¡uT already present in the logarithmic layer, the only two length-scales allowed if Townsend’s wall similarity hypothesis is valid.

Cyp7b, a novel brain cytochrome P450, catalyzes the synthesis of neurosteroids 7α-hydroxy dehydroepiandrosterone and 7α-hydroxy pregnenolone

Steroids produced locally in brain (neurosteroids), including dehydroepiandrosterone (DHEA), influence cognition and behavior. We previously described a novel cytochrome P450, Cyp7b, strongly expressed in rat and mouse brain, particularly in hippocampus. Cyp7b is most similar to steroidogenic P450s and potentially could play a role in neurosteroid metabolism. To examine the catalytic activity of the enzyme mouse Cyp7b cDNA was introduced into a vaccinia virus vector. Extracts from cells infected with the recombinant showed NADPH-dependent conversion of DHEA (Km, 13.6 μM) and pregnenolone (Km, 4.0 μM) to slower migrating forms on thin layer chromatography. The expressed enzyme was less active against 25-hydroxycholesterol, 17β-estradiol and 5α-androstane-3β,17β-diol, with low to undetectable activity against progesterone, corticosterone, and testosterone. On gas chromatography and mass spectrometry of the Cyp7b metabolite of DHEA the retention time and fragmentation patterns were identical to those obtained with authentic 7α-hydroxy DHEA. The reaction product also comigrated on thin layer chromatography with 7α-hydroxy DHEA but not with 7β-hydroxy DHEA; when [7α-3H]pregnenolone was incubated with Cyp7b extracts the extent of release of radioactivity into the medium suggested that hydroxylation was preferentially at the 7α position. Brain extracts also efficiently liberated tritium from [7α-3H]pregnenolone and converted DHEA to a product with a chromatographic mobility indistinguishable from 7α-hydroxy DHEA. We conclude that Cyp7b is a 7α-hydroxylase participating in the synthesis, in brain, of neurosteroids 7α-hydroxy DHEA, and 7α-hydroxy pregnenolone.

Occurrence of Cello-Oligosaccharides in the Apoplast of Auxin-Treated Pea Stems

Treatment of pea (Pisum sativum L.) hypocotyl segments with indole-3-butyric acid, which promotes segment elongation, increased the solubilization of both xyloglucan and cello-oligosaccharides in the apoplast of auxin-treated pea stems. The cello-oligosaccharides were isolated from the apoplastic solution with a charcoal/Celite column and were identified as cellobiose, cellotriose, and cellotetraose after subsequent thin-layer chromatography and paper electrophoresis. Cello-oligosaccharides in the apoplastic fraction were monitored using cellobiose dehydrogenase. Both xyloglucan and cello-oligosaccharides appeared to be formed concurrently within 30 min after treatment with the auxin, and the cello-oligosaccharides increased with stem elongation even after 2 h. The total activity of cellulase did not increase for up to 4 h.

Protein Phosphorylation during Coconut Zygotic Embryo Development1

Evidence was obtained on the occurrence of protein threonine, serine, and tyrosine (Tyr) kinases in developing coconut (Cocos nucifera L.) zygotic embryos, based on in vitro phosphorylation of proteins in the presence of [γ-32P]ATP, alkaline treatment, and thin-layer chromatography analysis, which showed the presence of [32P]phosphoserine, [32P]phosphothreonine, and [32P]phosphotyrosine in [32P]-labeled protein hydrolyzates. Tyr kinase activity was further confirmed in extracts of embryos at different stages of development using antiphosphotyrosine monoclonal antibodies and the synthetic peptide derived from the amino acid sequence surrounding the phosphorylation site in pp60src (RR-SRC), which is specific for Tyr kinases. Anti-phosphotyrosine western blotting revealed a changing profile of Tyr-phosphorylated proteins during embryo development. Tyr kinase activity, as assayed using RR-SRC, also changed during embryo development, showing two peaks of activity, one during early and another during late embryo development. In addition, the use of genistein, a Tyr kinase inhibitor, diminished the ability of extracts to phosphorylate RR-SRC. Results presented here show the occurrence of threonine, serine, and Tyr kinases in developing coconut zygotic embryos, and suggest that protein phosphorylation, and the possible inference of Tyr phosphorylation in particular, may play a role in the coordination of the development of embryos in this species.

Identification and Partial Characterization of the Pectin Methyltransferase “Homogalacturonan-Methyltransferase” from Membranes of Tobacco Cell Suspensions1

A membrane preparation from tobacco (Nicotiana tabacum L.) cells contains at least one enzyme that is capable of transferring the methyl group from S-adenosyl-methionine (SAM) to the C6 carboxyl of homogalacturonan present in the membranes. This enzyme is named homogalacturonan-methyltransferase (HGA-MT) to distinguish it from methyltransferases that catalyze methyletherification of the pectic polysaccharides rhamnogalacturonan I or rhamnogalacturonan II. A trichloroacetic acid precipitation assay was used to measure HGA-MT activity, because published procedures to recover pectic polysaccharides via ethanol or chloroform:methanol precipitation lead to high and variable background radioactivity in the product pellet. Attempts to reduce the incorporation of the 14C-methyl group from SAM into pectin by the addition of the alternative methyl donor 5-methyltetrahydrofolate were unsuccessful, supporting the role of SAM as the authentic methyl donor for HGA-MT. The pH optimum for HGA-MT in membranes was 7.8, the apparent Michaelis constant for SAM was 38 μm, and the maximum initial velocity was 0.81 pkat mg−1 protein. At least 59% of the radiolabeled product was judged to be methylesterified homogalacturonan, based on the release of radioactivity from the product after a mild base treatment and via enzymatic hydrolysis by a purified pectin methylesterase. The released radioactivity eluted with a retention time identical to that of methanol upon fractionation over an organic acid column. Cleavage of the radiolabeled product by endopolygalacturonase into fragments that migrated as small oligomers of HGA during thin-layer chromatography, and the fact that HGA-MT activity in the membranes is stimulated by uridine 5′-diphosphate galacturonic acid, a substrate for HGA synthesis, confirms that the bulk of the product recovered from tobacco membranes incubated with SAM is methylesterified HGA.

Submucosal gland secretions in airways from cystic fibrosis patients have normal [Na+] and pH but elevated viscosity

Fluid and macromolecule secretion by submucosal glands in mammalian airways is believed to be important in normal airway physiology and in the pathophysiology of cystic fibrosis (CF). An in situ fluorescence method was applied to measure the ionic composition and viscosity of freshly secreted fluid from airway glands. Fragments of human large airways obtained at the time of lung transplantation were mounted in a humidified perfusion chamber and the mucosal surface was covered by a thin layer of oil. Individual droplets of secreted fluid were microinjected with fluorescent indicators for measurement of [Na+], [Cl−], and pH by ratio imaging fluorescence microscopy and viscosity by fluorescence recovery after photobleaching. After carbachol stimulation, 0.1–0.5 μl of fluid accumulated in spherical droplets at gland orifices in ≈3–5 min. In gland fluid from normal human airways, [Na+] was 94 ± 8 mM, [Cl−] was 92 ± 12 mM, and pH was 6.97 ± 0.06 (SE, n = 7 humans, more than five glands studied per sample). Apparent fluid viscosity was 2.7 ± 0.3-fold greater than that of saline. Neither [Na+] nor pH differed in gland fluid from CF airways, but viscosity was significantly elevated by ≈2-fold compared to normal airways. These results represent the first direct measurements of ionic composition and viscosity in uncontaminated human gland secretions and indicate similar [Na+], [Cl−], and pH to that in the airway surface liquid. The elevated gland fluid viscosity in CF may be an important factor promoting bacterial colonization and airway disease.

Nitric oxide regulates vascular cell adhesion molecule 1 gene expression and redox-sensitive transcriptional events in human vascular endothelial cells.

Decreased nitric oxide (NO) activity, the formation of reactive oxygen species, and increased endothelial expression of the redox-sensitive vascular cell adhesion molecule 1 (VCAM-1) gene in the vessel wall are early and characteristic features of atherosclerosis. To explore whether these phenomena are functionally interrelated, we tested the hypothesis that redox-sensitive VCAM-1 gene expression is regulated by a NO-sensitive mechanism. In early passaged human umbilical vein endothelial cells and human dermal microvascular endothelial cells, the NO donor diethylamine-NO (DETA-NO, 100 microM) reduced VCAM-1 gene expression induced by the cytokine tumor necrosis factor alpha (TNF-alpha, 100 units/ml) at the cell surface level by 65% and intracellular adhesion molecule 1 (ICAM-1) gene expression by 35%. E-selectin gene expression was not affected. No effect on expression of cell adhesion molecules was observed with DETA alone. Moreover, DETA-NO suppressed TNF-alpha-induced mRNA accumulation of VCAM-1 and TNF-alpha-mediated transcriptional activation of the human VCAM-1 promoter. Conversely, treatment with NG-monomethyl-L-arginine (L-NMMA, 1 mM), an inhibitor of NO synthesis, augmented cytokine induction of VCAM-1 and ICAM-1 mRNA accumulation. By gel mobility shift analysis, DETA-NO inhibited TNF-alpha activation of DNA binding protein activity to the VCAM-1 NF-kappa B like binding sites. Peroxy-fatty acids such as 13-hydroperoxydodecanoeic acid (linoleyl hydroperoxide) may serve as an intracellular signal for NF-kappa B activation. Using thin layer chromatography, DETA-NO (100 microM) suppressed formation of this metabolite, suggesting that DETA-NO modifies the reactivity of oxygen intermediates in the vascular endothelium. Through this mechanism, NO may function as an immunomodulator of the vessel wall and thus mediate inflammatory events involved in the pathogenesis of atherosclerosis.

Targeted replacement of the mycocerosic acid synthase gene in Mycobacterium bovis BCG produces a mutant that lacks mycosides.

A single gene (mas) encodes the multifunctional enzyme that catalyzes the synthesis of very long chain multiple methyl branched fatty acids called mycocerosic acids that are present only in slow-growing pathogenic mycobacteria and are thought to be important for pathogenesis. To achieve a targeted disruption of mas, an internal 2-kb segment of this gene was replaced with approximately the same size hygromycin-resistance gene (hyg), such that hyg was flanked by 4.7- and 1.4-kb segments of mas. Transformation of Mycobacterium bovis BCG with this construct in a plasmid that cannot replicate in mycobacteria yielded hygromycin-resistant transformants. Screening of 38 such transformants by PCR revealed several transformants representing homologous recombination with single crossover and one with double crossover. With primers representing the hyg termini and those representing the mycobacterial genome segments outside that used to make the transformation construct, the double-crossover mutant yielded PCR products expected from either side of hyg. Gene replacement was further confirmed by the absence of the vector and the 2-kb segment of mas replaced by hyg from the genome of the mutant. Thin-layer and radio-gas chromatographic analyses of the lipids derived from [1-14C]propionate showed that the mutant was incapable of synthesizing mycocerosic acids and mycosides. Thus, homologous recombination with double crossover was achieved in a slow-growing mycobacterium with an intron-containing RecA. The resulting mas-disrupted mutant should allow testing of the postulated roles of mycosides in pathogenesis.

A general assay for antibody catalysis using acridone as a fluorescent tag.

A simple and highly sensitive catalysis assay is demonstrated based on analyzing reactions with acridonetagged compounds by thin-layer chromatography. As little as 1 pmol of product is readily visualized by its blue fluorescence under UV illumination and identified by its retention factor (Rf). Each assay requires only 10 microliters of solution. The method is reliable, inexpensive, versatile, and immediately applicable in repetitive format for screening catalytic antibody libraries. Three examples are presented: (i) the epoxidation of acridone labeled (S)-citronellol. The pair of stereoisomeric epoxides formed is resolved on the plate, which provides a direct selection method for enantioselective epoxidation catalysts. (ii) Oxidation of acridone-labeled 1-hexanol to 1-hexanal. The activity of horse liver alcohol dehydrogenase is detected. (iii) Indirect product labeling of released aldehyde groups by hydrazone formation with an acridone-labeled hydrazide. Activity of catalytic antibodies for hydrolysis of enol ethers is detected.