A low concentrating cell and receiver concept based on low cost silicon solar cells

A multi-use and low cost silicon concentrator solar cell and receiver concept is presented. It is based on a industrially feasible Metall Wrap Through concentrator solar cell available in various dimensions up to 156×156m. Solar cell performance evolution and current results are reported, with a top efficiency of 20.2% at 1W/cm² irradiance. The interconnection and receiver integration of the cells is demonstrated with several prototypes. A maximum cell-to-receiver efficiency of 99.3 % is shown, and a top receiver efficiency of 19.2 % at 1W/cm² irradiance is measured. Preliminary reliability testing sequences (humidity freeze, thermal cycling) and outdoor exposure results are passed without significant damages or IV power degradation (<1%)

FLATCON® CPV Module Technology: A New Design based on the Evaluation of 10 Years of Outdoor Measurement Data

In this paper, we present our experience in designing FLATCON® concentrator modules. The FLATCON® technology uses silicone-on-glass (SoG) Fresnel lenses and solar cells mounted to a metal heat distributor on a glass rear plate. During the past two decades, various FLATCON® module designs have been investigated. The first FLATCON® modules consisted of lenses with 16 cm² and GaAs single-junction solar cells with a diameter of 2 to 4 mm. In 2007, the first triple-junction solar cells with a diameter of 2.3 mm were integrated into FLATCON-type modules. The results of the test module ISE049T are discussed in this paper in detail. It was measured on the test tracker in Freiburg for more than 10 years. Moreover, the latest FLATCON® module design is presented together with the major manufacturing steps

Sustainable carbon sources for microbial organic acid production with filamentous fungi

Background: The organic acid producer Aspergillus oryzae and Rhizopus delemar are able to convert several alternative carbon sources to malic and fumaric acid. Thus, carbohydrate hydrolysates from lignocellulose separation are likely suitable as substrate for organic acid production with these fungi. Results: Before lignocellulose hydrolysate fractions were tested as substrates, experiments with several mono- and disaccharides, possibly present in pretreated biomass, were conducted for their suitability for malic acid production with A. oryzae. This includes levoglucosan, glucose, galactose, mannose, arabinose, xylose, ribose, and cellobiose as well as cheap and easy available sugars, e.g., fructose and maltose. A. oryzae is able to convert every sugar investigated to malate, albeit with different yields. Based on the promising results from the pure sugar conversion experiments, fractions of the organosolv process from beechwood (Fagus sylvatica) and Miscanthus giganteu s were further analyzed as carbon source for cultivation and fermentation with A. oryzae for malic acid and R. delemar for fumaric acid production. The highest malic acid concentration of 37.9 ± 2.6 g/L could be reached using beechwood cellulose fraction as carbon source in bioreactor fermentation with A. oryzae and 16.2 ± 0.2 g/L fumaric acid with R. delemar. Conclusions: We showed in this study that the range of convertible sugars for A. oryzae is even higher than known before. We approved the suitability of fiber/cellulose hydrolysate obtained from the organosolv process as carbon source for A. oryzae in shake flasks as well as in a small-scale bioreactor. The more challenging hemicellulose fraction of F. sylvatica was also positively evaluated for malic acid production with A. oryzae

Quantitative appraisal of bilateral sagittal split osteotomy impact on the loading of temporomandibular joint

Bilateral sagittal split osteotomy is one of the most frequently performed operations in orthognathic surgery. The health of the temporomandibular joint (TMJ) is an important prerequisite for its functionality. The aim of this finite element study was to assess the developed stresses during mouth opening after bilateral sagittal split osteotomy. Different osteotomy gap widths and disc positions were evaluated. Computed tomography and magnetic resonance data of a dentulous cadaver head were used in order to create two finite element models simulating split distances of 5 and 10 mm, respectively. The fixation of the distal and proximal segments was made by a four- or a six-hole titanium mini plate and four monocortical screws respectively. For both models, three different situations of the articular disc were created: a physiological disc position, anterior disc displacement and posterior disc displacement. The mandible was vertically displaced in the midline in order to simulate a mouth opening of 20 mm. The simulation showed high stresses in the area of the titanium plates (up to 850 MPa), implying an increased risk of material failure. High stresses were found within the discs in the models with normal disc position and anterior disc displacement as well (up to 8 MPa), indicating a higher risk of developing craniomandibular disorders. Regarding the stresses within the fixation screws, the highest values were recorded in the area of the upper thread. The degree of mandibular advancement after a bilateral sagittal split osteotomy affects the stress balance in the mandible and the articular discs during mouth opening. © 2020 Elsevier Lt

Development and Outdoor Characterization of a Hybrid Bifacial HCPV Module

Conversion of direct, diffuse, and albedo irradiance into electricity is demonstrated with a new kind of hybrid bifacial high‐concentration photovoltaic module named bifacial EyeCon. It consists of Fresnel lenses that concentrate the direct sunlight 321x onto III‐V triple‐junction solar cells that are mounted on the front surface of p‐PERC bifacial c‐Si cells. Thus, the Si absorbs the front and rear diffuse irradiance. Because III‐V and Si cells are electrically isolated (hence a 4‐terminal device) but thermally coupled by a dielectric adhesive, Si also acts as a heat distributing substrate. To accommodate the concentrator cells, we adapted the metallization layout and also optimized it for low intensity, ie, 200 W/m2 on the front and 100 W/m2 on the rear, using finite element network simulation. Additionally, when the concentrator cells are mounted on a bifacial Si cell instead of a metal heat distributor, their operating temperature is 16 K higher. However, we demonstrate with outdoor measurements that the power output of the bifacial EyeCon module reaches up to 326 W/m2 when the direct to global irradiance ratio is 92%. At a lower fraction of 70% the bifacial Si cells augment the power output of the III‐V string by 19%rel