Optimization of lead- and cadmium-free front contact silver paste formulation to achieve high fill factors for industrial screen-printed Si solar cells

Screen-printed n⁺–p–p⁺ solar cells were fabricated on Cz single crystalline Si material, with a 45 Ω/sq emitter and PECVD SiNx antireflective coating with a thickness of 700 Å, using different Ag pastes and commercial leaded reference paste (CN33-462, Ferro Corp.). Ag and Al contacts were co-fired using a mass-production line equipped with mesh belt conveyer furnace systems (Centrotherm thermal solution GmbH & Co. KG). The average results for single crystalline Si solar cells (156 cm²) are: I_sc=5.043 A, V_oc=0.621 V, R_s=0.0087 Ω, R_sh=15.3 Ω, FF=0.773, and E_ff=16.45%. R_sh and fill factor values of fabricated cells were slightly higher when compared with the commercial leaded Ag paste, although cells were fabricated by metallizing the lead-free silver pastes. For the lead-free Ag paste used in this study, the line pattern continuity is retained with improved edge definition in sharp contrast to that of reference Ag paste. Average value of R_s was also equivalent approximately to that of the leaded Ag paste.     

Virtual reality for cultural landscape visualization

Although land managers and policy-makers generally have a good experience of what result can be expected from their decisions, they are often faced with difficulty when trying to communicate the visual impact of a management option to stakeholders, particularly when the landscape exhibits a high cultural value. Three-dimensional visualization of the landscape is often used for communicating with the stakeholders. A challenge in participatory methods for integrated assessment and policy planning is to view future changes in land use, according to scenarios. A 3-D landscape visualization component, SLE (“Seamless Landscape Explorer”), has been developed, which is launched after a scenario simulation to allow for exploration of landscape changes. Pressures causing such changes are translated into changes in the spatial configuration of the landscape. The different types of land-use are visualized thanks to a library of detailed textures, and vegetation can be added. This has been applied to a study of four scenarios in the French Mediterranean region, which were set up as part of a participatory process for discussing the planning of the regional peri-urban and agricultural policy, in an area dominated by the typical culturally sensitive Mediterranean matorral, (“garrigue” shrubland) surrounding the Pic Saint-Loup mountain. Examples of visualization are shown and discussed here.     

Sequential or parallel processes? A longitudinal field study concerning determinants of identity-management strategies.

Using a longitudinal field design, this study tested the dynamics of an integrative model of social identity theory (SIT) and relative deprivation theory (RDT) with regard to relations between perceived sociostructural characteristics, perceived in-group identification, perceived fraternal deprivation (i.e., resentment) and identity-management-strategy preference. Trait-state analyses revealed that the dynamic relationship among constructs in the model can best be explained in terms of trait-dependent variation rather than sequentially ordered processing. The trait components of the variables replicate previous findings concerning SIT and RDT. However, stable functional relations between variables and their traitlike character contradict the notion that their underlying processes are linear and sequential. Rather, variables and their relations can be regarded as the product of parallel processes. The authors discuss the results as a challenge to core assumptions of SIT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

La mesure de perfectionnisme: Validation canadienne-fran?aise du Positive and Negative Perfectionism Scale.

The purpose of this study was to verify the validity of a French version of the Positive and Negative Perfectionism Scale developed by L. A. Terry-Short (1995). This instrument measures the type as well as the level of perfectionism in adolescents. The instrument was first administered to 734 7th, 9th, and 11th grade students. Four weeks later, 596 Ss were invited to answer the questionnaire once more. The factorial structure, temporal stability and internal consistency of each subscales of the translated version of the instrument correspond to those of the original version. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment

Objective: The aim of this study was to evaluate a formulation made of poly(lactide-co-glycolide) (PLGA) nanoparticles containing azelaic acid for potential acne treatment.

Methods: Azelaic acid-loaded PLGA nanoparticles were prepared by spontaneous emulsification processes using poloxamer 188 as stabilizer. Several manufacturing parameters such as stirring rate, concentration of stabilizer and different recovery methods were investigated. Nanoparticles were evaluated in terms of size, zeta potential, encapsulation efficiency, release kinetics and permeation kinetics in vitro. Furthermore, in vitro toxicological studies were performed in Saccharomyces cerevisiae model.

Results: The results showed that by adjusting some formulation conditions it was possible to obtain nanoparticles with high loading and a controlled drug release. Freeze-dried recovery altered the nanoparticles structure by enhancing porous structures and mannitol was required to control the mean particle size. The centrifugation recovery was found to be the best approach to nanoparticles recovery. Similar toxicity profiles were observed for both drug-free and azelaic acid-loaded nanoparticles, with concentration-dependent decreases in cell viability.

Conclusion: These results indicate a potential formulation for controlled release delivery of azelaic acid to the follicular unit.     

Mobilization and deposition of iron nano and sub-micrometer particles in porous media: a glass micromodel study

Mobilization and deposition of iron nano and sub-micrometer particles (INSMP) in a porous medium were investigated using a water-saturated glass micromodel. The deposition and detachment of INSMP in the micromodel were visualized by taking serial images and experimentally verified by analysis of breakthrough curves. This first visualization study of INSMP fate showed that there were dense aggregations at the pores as the concentration of INSMP increased. The presence of dissolved humic substances (>1 ppm) significantly reduced deposition of suspended particles and enhanced detachment of the deposited particles. The mobility of INSMP in the presence of Pahokee peat fulvic acid standard II (PPFA) was higher than for Pahokee peat humic acid standard I (PPHA) due to the presence of more aromatic groups and the molecular weight in PPFA. Interfacial energy estimation based on the DLVO theory revealed that the adsorption of humic substances onto the INSMP increased the energy barrier and reduced the depth of secondary minimum between particles. The “affinity transition” in the initial deposition of INSMP within the micromodel was observed in the presence of Pahokee peat humic substances.     

Opposing actions of BMP3 and TGF beta 1 in human bone marrow stromal cell growth and differentiation

BMP3 and TGF beta 1 were found to induce opposite effects on human bone marrow stromal cells both in cell proliferation and cell differentiation and on calcium deposition onto the extracellular matrix. Moreover, BMP3 may exert, in part, the inhibitory effect of TGF beta 1 through decreasing the affinity of TGF-beta for its receptors which are now identified in these human bone cells.