Direct processing of structural thermoplastic composites using rapid isothermal stamp forming

A novel rapid isothermal stamp forming process is proposed which enables the rapid manufacture of structural thermoplastic composite laminate parts directly from multilayer hybrid fabrics comprising stitched unidirectional carbon fibre-thermoplastic polymer veil. The process employs rapid-response variothermal tooling, allowing macro-scale (fabric forming/draping) and micro-scale (fibre wetting/laminate consolidation) composite material transformation processes to occur isothermally above the constituent polymer matrix melt temperature (Tm), thus manufacturing a composite component directly from a hybrid dry fabric in a single press cycle in a relatively short overall cycle time. The proposed rapid isothermal stamp forming (RISF) concept is presented, and details of the process are given along with some considerations made throughout the formulation of the process. As a result of the RISF process development work, candidate manufacturing parameters were derived, delivering parts that exhibit acceptable composite laminate microstructure and mechanical performance within a press station cycle time of 330 s

Chlorella vulgaris modulates hydrogen peroxide-induced dna damage and telomere shortening of human fibroblasts derived from different aged individuals

The objective of this study was to investigate the modulatory effect of Chlorella vulgaris on cultured fibroblast cells derived from young and old aged individuals focusing on DNA damage, telomere length and telomerase activity. Dose-response test of the algal extract on cells in both age groups revealed that optimum viability was observed at a concentration of 50 μg/ml. Results obtained showed that Chlorella vulgaris exhibited protective effects against H2O2-induced oxidative stress as shown by the reduction in damaged DNA caused by H2O2 treatment (

Leaf Surface Characteristics of Selected Malaysian Weed Species of Oil Palm

Laboratory and glasshouse studies were conducted to examine the leaf surface characteristics of selected weed species of oil palm. The broadleaf weeds selected were Asystasia gangetica, Borreria latifolia, Cleome rutidosperma, Clidemia hirta, Diodia ocimifolia and Mikania micrantha, while for the narrow leafs, Axonopus compressus, Cyperus kylingia, Eleusine indica, Paspalum conjugatum and Pennisetum polistachyon were investigated. The weeds were categorized into different types of roughness based on the macroscopic roughness, microscopic roughness and the estimation of three roughness parameters: Ra (arithmetic average height parameter), Rq (root-mean-square roughness parameter, corresponding to Ra), and Rz (average of high peaks and low valleys over the evaluation length). The leaf was examined using scanning electron microscopy (SEM) for the surface roughness, while the epicuticular wax content of the leaf was extracted using chloroform. The amount of wax extracted from the weeds varied between species. For broadleaf plants, Mikania micrantha (44.22 µg/cm2) was identified as the plant that contained the highest quantity of wax. Clidemia hirta (24.03 µg/cm2) and Asystasia gangetica (23.03 µg/cm2) were grouped in the plants with a medium quantity of wax while Cleome rutidosperma (16.52 µg/cm2), Borreria latifolia (14.19 µg/cm2) and Diodia ocimifolia (10.75 µg/cm2) were grouped in the plants with a low quantity of cuticular wax weight. For narrow leaf plants, Eleusine indica (44.23 µg/cm2) and Imperata cylindrica (49.88 µg/cm2) were recognized as the plants that contained a high quantity of wax. Pennisetum polystachion (32.16 µg/cm2) and Cyperus kylingia (22.85 µg/cm2) were categorized under the plants with a medium quantity of wax, whereas Paspalum conjugatum (19.59 µg/cm2) and Axonopus compressus (16.78 µg/cm2) were classified under the plant with a low quantity of wax. The wax on the abaxial surface data of the broadleaf weeds was found to be significantly different when compared to the adaxial surface data. In contrast, the amount of wax on the abaxial and adaxial leaf surface of the narrow leaf weeds was more or less similar. For the leaf surface roughness of the broadleaf species, Borreria latifolia was categorized as the roughest, followed by Clidemia hirta, Diodia ocimifolia, Asystasia gangetica and Cleome rutidosperma. Mikania micrantha had the smoothest leaf surface among the broadleaf species. On the other hand, the narrow leaf of Pennisetum polistachyon was identified as the roughest, followed by Imperata cylindrica and Paspalum conjugatum, while Eleusine indica, Axonopus compressus and Cyperus kylingia were categorized as having the smoothest leaf surface

Geotechnical Application for the Design and Estimation of Amata-Lekwesi, Nigeria Open Mine

The need for a proper understanding of the subsurface geology of a place and the depositional pattern of what is to be mined is very important in establishing its mining trend especially if such deposits are not exposed at the surface. Eleven borings were made in the quarry pit and around the surrounding berm to depths of 25 meters at a sampling interval of 1.0m into the intrusive rock bodies using Slanzi rotary diamond coring rig. The depth range of the boreholes varies from 15.0 meters to 25.0 meters. Rock/Soil samples obtained from borings were subjected to both visual field examination and laboratory tests/analyses to guide in designing a mine system that is based on the geology, trending pattern and geotechnical properties of the rocks. The intrusive was observed to trend in the east-west orientation. However, north-south trends were also observed at certain sections of the mine/quarry. The values of the plunges of the intrusive were observed to be between 2o and 6o at the northern southern segments. The average thickness of the intrusive bodies varies from 11.20m for the surrounding bench area to 20.00m in the pit. This observed thickness of rock mass covers an area of approximately 81,750 m2, made up of 29,500 m2 for the floor of the quarry and 52,250 m2 for the surrounding bench. The area of the surrounding berm and the pit floor area are  52,250 m2 and 29,500m2 respectively. A total reserve tonnage of 3,874,000 was obtained. Keywords: Geotechnical, Mining design, intrusive body, Slanzi rotary diamond coring rig, Quarry, Trend, Plung

Did Corruption Decrease Post-Crisis? The Case of Wholesalers across Less-Developed Economies

This study examines informal payments/gifts paid by wholesalers during and postcrisis periods. We find that bribes were less frequent for wholesalers in general, post-crisis. The results hold for certain groups of wholesalers when they are classified with respect to structure, size, structure, legal form, and owner and manager’s gender. However, we do not find much evidence of significant difference between the crisis and post-crisis period in terms of the incidence of bribes when we categorize them into customs/imports, courts, and taxes

The effect of financial crises on stock market liquidity across global markets

In this study, using a widely available market liquidity measure, the “turnover ratio”, the authors test for market liquidity contagion during the four financial crises that occurred between 1997 and 1999: The Thai crisis, the Hong Kong crisis, the Russian crisis, and the Brazilian crisis. It is found that while the liquidity levels decreased in approximately half of the sample markets, in the remaining half, the liquidity levels actually improved. The Granger causality tests show that while there is almost no evidence of causality (in both directions) before each crisis, during each crisis, approximately half of the pairwise tests were significant. The results show that most of these causalities are reverse feedback effects from the non-crisis-origin markets to the crisis-origin market. Therefore, it is concluded that the more crucial phenomenon during these crises is the “reverse feedback effects” rather than the liquidity contagion itself

Swarm optimization based radio resource allocation for dense devices D2D communication

In Device to Device (D2D) communication two or more devices communicate directly with each other in the in-band cellular network. It enhances the spectral efficiency due to cellular radio resources (RR) are shared among the cellular users and D2D users. If the RR sharing is not legitimate properly, it causes interference and inefficient use. Therefore, management of RR between cellular users and D2D users is required to control the interference and inefficient use of RR. In D2D enabled cellular network, D2D users have a good signal to noise ratio (SNR) compared with cellular users due to the short distances and dedicated path. Using this advantage, an efficient RR allocation algorithm based on swarm optimization is proposed in this paper, that allows utmost spatial reuse in multi-users and OFDMA networks. The algorithm determines the required RR on the request of D2D users following the indicator variable. It enhances the capacity (Bit/Hz), overall system throughput and spectral efficiency with respect to sub-carriers in OFDMA networks. The performance of the proposed algorithm is evaluated via MATLAB simulations

Fatty acids composition of microalgae Chlorella vulgaris can be modulated by varying carbon dioxide concentration in outdoor culture

Varying culture methods of Chlorella vulgaris (CV) has been associated with different nutrient composition. The aim of this study was to investigate the fatty acid contents and other nutrients of CV subjected to various culturing conditions. We found that CV cultured under 24 h light and 10% CO2 showed the best growth rates and contained higher lipid, protein and moisture contents compared to other culture conditions. Interestingly, the content of fatty acids of CV was dependent on the amount of CO2. Fatty acid analysis of CV by gas chromatography-mass spectrometry (GC-MS) showed the presence of cis-10-pentadecanoic acid (C15:1), palmitic acid (C16:0), palmitoleic acid (C16:1), heptadecanoic acid (C17:0), stearic acid (C18:0), oleic acid (C18:1n9c), linoleic acid (C18:2n6c), linolenic acids (C18:3n3) and arachidic acid (C20:0). Remarkably, polyunsaturated fatty acids (linoleic and linolenic acids) are found in abundance compared to other fatty acids in CV. The concentrations of palmitic, oleic, linoleic and linolenic acids increased when the amount of carbon dioxide was raised from 1 to 10% under both culture conditions (12 and 24 h light). This study shows the possibility of modifying lipid contents in freshwater microalgae by varying the amount of carbon dioxide and light.Key words: Chlorella vulgaris, microalgae, fatty acids, vitamins, minerals, carbon dioxide

A versatile source of polarisation entangled photons for quantum network applications

We report a versatile and practical approach for generating high-quality polarization entanglement in a fully guided-wave fashion. Our setup relies on a high-brilliance type-0 waveguide generator producing paired photon at a telecom wavelength associated with an advanced energy-time to polarisation transcriber. The latter is capable of creating any pure polarization entangled state, and allows manipulating single photon bandwidths that can be chosen at will over five orders of magnitude, ranging from tens of MHz to several THz. We achieve excellent entanglement fidelities for particular spectral bandwidths, i.e. 25 MHz, 540 MHz and 100 GHz, proving the relevance of our approach. Our scheme stands as an ideal candidate for a wide range of network applications, ranging from dense division multiplexing quantum key distribution to heralded optical quantum memories and repeaters.Comment: 5 figure