Highly efficient large area (10.5%, 1376 cm) thin-film CdS/CdTe solar cell

Highly efficient large area (10.5%, 1376 cm²) thin-film CdS/CdTe solar cell sub-module has been fabricated. Very recently we also have fabricated a very large area sub-module of aperture area 5413 cm² exhibiting a conversion efficiency of 8.4%. Such a high efficiency has been achieved by depositing all the constituent films such as SnO₂: F, CdS and CdTe having greater uniformity and better quality under atmospheric pressure conditions. A post deposition treatment of CdTe surface with CdCl₂ has been optimized to improve the overall solar cell output performance significantly.     

Numerical simulation of damage progression and fracture in structures made of 3D woven ceramic matrix composites

This paper proposes numerical simulation to predict damage progression and critical strength in structural components made of 3D woven ceramic matrix composites (CMCs). This method implements three numerical approaches with the commercial finite element method. (i) Damage models are used to predict damage initiation and propagation of CMCs. (ii) The failure criterion based on the Weibull volumetric statistical strength model is implemented to take into account the size effects of fiber-bundle strength. (iii) The nonlocal damage theory is implemented to confirm the mesh independence of the results and the convergence of computation. To verify the accuracy of the two damage models, simulations of smooth SiC/SiC specimens were performed. Furthermore, several kinds of open-hole SiC/SiC tensile test were simulated to verify the accuracy of the proposed numerical simulation. Finally, the proposed numerical simulation was validated by detailed comparisons of experiment and simulation.     

Relationship between Pectic Substances and Strand Separation of Cooked Spaghetti Squash--Part 2. Changes in Firmness,Histological Structure and Pectic Substances during Soaking in Pectin Extractants

The flesh of spaghetti squash separates into strands when cooked. The purpose of this paper is to investigate the cause of strand separation （during cooking） by soaking for 24 h at 35 ℃ in solutions with three kinds of pectin extractant. The changes in strand separation, firmness, histological structure and the pectin of flesh during soaking in 0.01 N HCI solution （pH 2.0）, 0.035 M ammonium oxalate solution （pH 4.0） or 2% sodium hexametaphosphate solution （pH 4.0） were investigated. When flesh was soaked in the HCI solution, the separation into strands and removal of calcium and magnesium were greater than that soaked in other pectin extractants. High methoxyl pectin was extracted by soaking in HC1 solution （pH 2.0） due to removal of polyvalent cations. This result shows that high methoxyl pectin glues strands together in the flesh of spaghetti squash. The shape of the cells which constituted strands was round; on the other hand, that of cells surrounded strands was elongated. When cooked in boiling water or soaked at pH 2.0, the shape of the former cells was maintained, but the latter cells, which contributed to adhesion between strands, broke down. Thus, the flesh separated into strands. When flesh was boiled for 15-30 min, pectin degraded and dissolved in the cooking solution; consequently, the flesh separated into strands and also the middle lamella of cell walls of strands separated. However, pectin remaining in strands maintained their crispness.     

Going beyond energy accounting for sustainability: Energy,fund elements and the economic process

The main purpose of this paper is to examine to what extent the widely used energy accounting schemes are useful for dealing with sustainability issues in view of Georgescu-Roegen’s production process and its implications for the evolutionary aspects of the economic process. The first part critically examines the concept of “net energy” in relation to material elements produced and consumed in the economic process in light of Georgescu-Roegen’s bioeconomics. The first part also considers the issue of what is produced in the economic process and emphasizes the importance of matter in bulk. The second part first compares the theoretical basis of embodied energy analysis (EEA) from the point of view of Piero Sraffa, a point of view not examined by Georgescu-Roegen. The second part also examines EEA critically in terms of Georgescu-Roegen’s flow-fund model and compares Sraffa’s analysis and Georgescu-Roegen’s flow-fund model.     

Hijiki seaweed consumption elevates levels of inorganic arsenic intake in Japanese children and pregnant women

Although exposure to inorganic arsenic is a health concern, especially in developing foetuses and children, dietary exposure levels among pregnant women and children have not been extensively studied in Japan. To address this shortcoming, we completed a 3-day duplicate diet study for 104 children and 101 pregnant women in two cities, Shimotsuke, Tochigi and Asahikawa, Hokkaido. The levels of intake of total and inorganic arsenic were estimated using the concentrations of total and inorganic arsenic in food and drinking water measured by inductively coupled plasma-mass spectrometry. Estimated intakes of total and inorganic arsenic were 8.46 ± 3.02 [µg/kg BW/week] and 1.74 ± 1.07 [µg/kg BW/week] in pregnant women and 20.07 ± 3.53 [µg/kg BW/week] and 8.46 ± 3.02 [µg/kg BW/week] in children, respectively. Weekly arsenic exposure per kg body weight was significantly higher in children than in pregnant women. Concentrations of total arsenic were generally very low in collected drinking water samples with a small number of exceptions, and drinking water was not considered as a major source of inorganic arsenic exposure in Japan. We found that total and inorganic arsenic intake were higher among frequent consumers of hijiki seaweed, in both pregnant women and children. Although rice and rice products that are staple foods of the Japanese have been reported to be major sources of inorganic arsenic exposure in Japan, our results indicate that hijiki consumption elevates levels of inorganic arsenic in Japanese children and pregnant women. More efforts are necessary to reduce the risk of exposure to inorganic arsenic in populations highly sensitive to environmental pollutants.     

Enhanced bactericidal action and masking of allergen structure of soy protein by attachment of chitosan through maillard-type protein-polysaccharide conjugation

The soy protein-chitosan conjugate was formed by the Maillard reaction in dry state (relative humidity 65%) at 60 degrees C for 2 weeks to improve the functional properties. The antimicrobial activity of the Maillard-type soy protein-chitosan conjugates enhanced 2-3 times that of soy protein-chitosan mixture. The soy protein-chitosan conjugate showed excellent emulsifying property with the progress of Maillard-type conjugation. The allergenicity of soy protein was greatly decreased by the attachment of chitosan through Maillard reaction. The immonoblotting analysis with patient's sera revealed that soy protein-chitosan conjugate was more effective to mask the allergen structure of soy protein causing from 34 kDa-protein (Gly m Bd 30K) than soy protein-galactomannan conjugate. The Western blotting showed that allergen (34 kDa-protein) was completely masked by soy protein-chitosan conjugation, while it was not completely masked by soy protein-galactomannan conjugation.     

Overexpression of 1-Deoxy-D-xylulose-5-phosphate reductoisomerase gene in chloroplast contributes to increment of isoprenoid production

Plants synthesize a large number of isoprenoid compounds that are of industrial, nutritional and medicinal importance. 1-Deoxy-D-xylulose reductoisomerase (DXR) catalyzes the first committed step of plastidial isoprenoid-precursor biosynthesis. In the present study, we generated transplastomic tobacco plants that overproduced DXR from Synechosystis sp. strain PCC6803. The transformants showed increase in the content of various isoprenoids such as chlorophyll a, beta-carotene, lutein, antheraxanthin, solanesol and beta-sitosterol, indicating that the DXR reaction is one of the key steps controlling isoprenoid level in tobacco leaves. A qualitative change in isoprenoid composition was also observed. The growth phenotype of the transplastomic plants was similar to that of wild-type plants. These results showed that plastid metabolic engineering is useful in manipulating the yield of isoprenoids in plants.     

Separation of oil-in-water emulsions by microbubble treatment and the effect of adding coagulant or cationic surfactant on removal efficiency

This study examined the efficiencies of microbubble (MB) treatment, MB treatment with polyaluminium chloride (PAC) as a coagulant, and MB treatment with cetyltrimethylammonium chloride (CTAC) as a cationic surfactant in the separation of emulsified oil (EO) by modified column flotation. Batch mode experiments were conducted by synthesizing emulsified palm oil (d<20 μm), and the chemical oxygen demand (COD) of the influent and effluent was measured to evaluate the treatment performance. MB treatment with PAC and MB treatment with CTAC were found to be more efficient in EO removal than the MB treatment alone. At an EO concentration of ～1,000 mg L(-1) (pH 7) and under identical treatment conditions (MB generation time: 2.5 min, flotation time: 30 min), MB treatment with PAC (50 mg L(-1)) and that with CTAC (0.5 mg L(-1)) showed equally high EO removal efficiencies of 92 and 89%, respectively. This result is of significant relevance to studies focusing on the development of economical and high-efficiency flotation systems. Furthermore, the effect of pH was investigated by varying the sample pH from 3 to 8, which showed that the EO separation efficiency of MB alone increased drastically from slightly alkaline to acidic condition.     

Removal of hydrogen sulfide using palygorskite in a fixed bed adsorber

This work describes the use of a novel palygorskite, a type of magnesium aluminium silicate clay possessing a high specific surface area and pore surface activity, as a low cost and highly efficient adsorbent for hydrogen sulfide (H(2)S) removal. Adsorption of H(2)S on palygorskite pretreated with acid or base was investigated in a fixed bed adsorber. The samples after base pretreatment had better dynamic adsorption performances than raw material and samples pretreated with acid. The H(2)S adsorption capacity decreased with an increase in inlet H(2)S concentration. This can be interpreted by the fact that H(2)S adsorption on the surface of palygorskite is chemisorption. The adsorption capacity increased from 25 to 50 °C, then decreased from 50 to 100 °C, which indicates that chemisorption took place and its better reaction temperature was around 50 °C.