Graft polycondensation of microfibrillated jute cellulose with oligo(L‐lactic acid) and its properties

In order to improve the compatibility with different polymer matrices, microfibrillated jute cellulose (MFJC) was surface grafted by oligo(l ‐lactic acid) (OLA) via graft polycondensation reaction catalyzed by Sn(Oct)₂ in toluene medium. The effects of the OLA concentration, Sn(Oct)₂ concentration, reaction time, temperature, and pressure on the progress of the graft polycondensation were investigated. Maximum grafting was found 44% at optimum reaction condition. The observation was confirmed by Fourier transform infrared spectroscopy, ¹³C‐NMR spectrometry, and X‐ray photoelectron spectroscopy. The morphology and crystalline structure of the graft copolymer (MFJC‐g‐OLA) were examined by scanning electron microscopy and wide angle X‐ray diffraction, respectively. Measurements showed that initial morphological integrity of MFJC changed due to incorporation of amorphous OLA onto MFJC surface, as a result decreases crystallinity. Extracted MFJC‐g‐OLA was also characterized by thermo‐gravimetric analysis. Results reflect the enhanced hydrophobicity and thermal stability of the MFJC as a consequence of this modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40139.     

Preparation and characterization of polypropylene composites reinforced with chemically treated coir

In the present work chemically treated coir reinforced polypropylene composites were fabricated by injection molding method. Raw coir was chemically treated by a simple two-step reaction. The mechanical properties of the treated coir reinforced polypropylene (PP) composites were found to be much improved compared to the corresponding values of the untreated ones. Water absorption of the composites increased with an increase in fiber content. However, treated coir-PP composites showed lower water uptake capacity compared to those prepared from untreated coir, indicating that upon chemical treatment the number of hydroxyl groups in the cellulose of coir has decreased, giving reduced the hydrophilic nature of the fiber. The surface morphology of the composites obtained from scanning electron microscopy (SEM) showed that raw coir-PP composites possess microvoids, fiber agglomerates and surface roughness with extruded fiber moieties. However, due to favorable interaction between the treated coir and the PP matrix, agglomerates and micro-voids in the composites have largely minimized showing better dispersion of the fiber in the matrix. It was concluded that upon surface modification hydrophilic nature of coir has largely minimized, giving better fiber-matrix interfacial adhesion and improved mechanical properties of the composites.     

Charge photogeneration in hybrid solar cells: a comparison between quantum dots and in situ grown CdS

We demonstrate that blend films containing poly(3-hexylthiophene-2,5-diyl) and in situ grown CdS display a greater yield of photogenerated charges than a blend containing an equivalent amount of pre-synthesised CdS quantum dots. Moreover, we show that the greater charge yield in the in situ grown films leads to an improvement in device efficiency. The present findings also appear to suggest that charge photogeneration at the CdS/polymer heterojunction is facilitated by the formation of nanoparticle networks as a result of CdS aggregation.     

Bioregenerative life support as self-sustaining ecosystem in space

Recent results of research on the development of biological systems and the related technologies for life support ecosystem in space have been reviewed. The integration of higher plants and algal subsystems and the technologies for food and atmospheric regeneration, water reclamation as waste recycling are the aspects which have been dealt with and need critical evaluation before they can be tested in space. The adaptation of living organisms and their ability to multiply and regenerate in space environment during long duration missions is one of the important criteria for their final selection. It is not yet clear to what extent bioregenerative subsystems can be accommodated in the space station Freedom, which will depend on their mass and functional stability, maintainability and operational cost. But it can be expected that bioregenerative life support systems will continue to evolve during the life time of space station Freedom leading towards an integrated ecosystem with further simplification and an increased degree of closure. Several biological and physico-chemical life support systems currently developed are under investigation on the MIR space station.     

A locus for autosomal recessive hypodontia with associated dental anomalies maps to chromosome 16q12.1

Lumbosacral defects on 20 patients were covered with a perforator-based flap. Cutaneous perforators derived from the 9th and 10th intercostal arteries, the 4th lumbar artery, and multiple gluteal perforators that penetrate the gluteus maximus muscle were used as vascular pedicles. Minor complications occurred in five cases. Using this method, minimal morbidity of the donor site is expected because the gluteus maximus need not be sacrificed. Accordingly, perforator-based flaps are especially indicated for ambulatory patients, but for paraplegic patients as well. Even in the event of recurrence, another perforator-based or musculocutaneous flap can be elevated from the ipsilateral side because of the presence of multiple perforators in the lumbosacral and gluteal regions.     

Properties of concrete with and without calcium chloride during drying and wetting

The effect of calcium chloride on the direct tensile strength of hardened cement paste and concrete cylindrical and prismatic specimens are investigated. Two different techniques for the determination of the direct tensile strength i.e. cylinders with embedded bars and prisms with glued end blocks are used. The results indicate that the addition of 2% calcium chloride significantly increases the direct tensile strength and the dynamic modulus of hardened cement paste. It is concluded that the addition of calcium chloride can partially inhibit the cracking caused by drying and sorption induced microcracking in the concrete system.     

Assessment of the Actual Performance of an Industrial Solar Kiln for Drying Timber

The aim of this study was to assess the actual performance of an instrumented industrial solar kiln for drying Australian hardwood timber (Eucalyptus pilularis) boards (270 × 43 mm). Ambient temperature and humidity, air temperature and humidity in the kiln, and wood moisture contents were recorded on site (Heron's Creek, NSW, Australia) using sensors and an electronic data acquisition and logging system. The average increases in air temperatures in the kiln compared with ambient conditions were 17.3°C (May-June), 13.8°C (July-August), 10°C (September-October), 8.2°C (November-March), and 7.5°C (March-May) for five runs monitored. Drying times were 2-4 months from initial moisture contents of 43 to 62% (dry-basis) to final moisture contents of 12 to 22%. Overall, the solar kiln has been shown to be an acceptable alternative to air-drying for pre-drying of Australian hardwood timber.