11,841 research outputs found
Hydrogen and fuel cell technologies for heating: A review
The debate on low-carbon heat in Europe has become focused on a narrow range of technological options and has largely neglected hydrogen and fuel cell technologies, despite these receiving strong support towards commercialisation in Asia. This review examines the potential benefits of these technologies across different markets, particularly the current state of development and performance of fuel cell micro-CHP. Fuel cells offer some important benefits over other low-carbon heating technologies, and steady cost reductions through innovation are bringing fuel cells close to commercialisation in several countries. Moreover, fuel cells offer wider energy system benefits for high-latitude countries with peak electricity demands in winter. Hydrogen is a zero-carbon alternative to natural gas, which could be particularly valuable for those countries with extensive natural gas distribution networks, but many national energy system models examine neither hydrogen nor fuel cells for heating. There is a need to include hydrogen and fuel cell heating technologies in future scenario analyses, and for policymakers to take into account the full value of the potential contribution of hydrogen and fuel cells to low-carbon energy systems
Effect of Tao-Hong-Si-Wu-Tang, a Traditional Chinese Herbal Medicine Formula, on Physical Fatigue in Mice
Tao-Hong-Si-Wu-Tang (THSWT) is a famous traditional Chinese herbal medicine formula, which has traditionally been used in China for about one thousand years. The present study investigated the effect of THSWT on physical fatigue. 32 male mice were randomly divided into 4 groups with 8 in each group. All were administered orally and daily for 28 days. Group I received isotonic saline solution as control; Group II, III and IV obtained 5, 10 and 20ml/ kg body weight of THSWT solutions, respectively. After 28 days, the anti-physical fatigue effect of THSWT was evaluated by using a forced swimming test, along with the determination of blood lactic acid, blood urea nitrogen (BUN), liver glycogen and muscle glycogen contents. The data showed that THSWT could extend exhaustive swimming time of mice, as well as decrease the BLA and BUN contents and increase the liver glycogen and muscle glycogen contents. The results support that THSWT had anti-physical fatigue effect
Regulation of notch sensitivity of lattice materials by strut topology
We propose a local reinforcement technique for lattices in the vicinity of a
stress-raiser such as a notch, in order to elevate the macroscopic strength and
ductility. A spatially non-uniform waviness distribution of sinusoidally-shaped
struts is assumed in the vicinity of the notch, and the sensitivity of
macroscopic tensile response to strut waviness distribution is studied by
finite element analysis. Optimized lattice structures are determined in order
to maximise the macroscopic tensile strength or ductility from these various
strut waviness distributions. Both hexagonal and triangular lattices are
studied as these geometries are representative of bending-dominated and
stretching-dominated lattices, respectively
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The Influence of Strut Waviness on the Tensile Response of Lattice Materials
Abstract
Recent advances in additive manufacturing methods make it possible, for the first time, to manufacture complex micro-architectured solids that achieve desired stress versus strain responses. Here, we report experimental measurements and associated finite element (FE) calculations on the effect of strut shape upon the tensile response of two-dimensional (2D) lattices made from low-carbon steel sheets. Two lattice topologies are considered: (i) a stretching-dominated triangular lattice and (ii) a bending-dominated hexagonal lattice. It is found that strut waviness can enhance the ductility of each lattice, particularly for bending-dominated hexagonal lattices. Manufacturing imperfections such as undercuts have a small effect on the ductility of the lattices but can significantly reduce the ultimate tensile strength. FE simulations provide additional insight into these observations and are used to construct design maps to aid the design of lattices with specified strength and ductility.</jats:p
Estimation of global final-stage energy-return-on-investment for fossil fuels with comparison to renewable energy sources
Under many scenarios, fossil fuels are projected to remain the dominant energy source until at least 2050. However, harder-to-reach fossil fuels require more energy to extract and, hence, are coming at an increasing ‘energy cost’. Associated declines in fossil fuel energy-return-on-investment ratios at first appear of little concern, given that published estimates for oil, coal and gas are typically above 25:1. However, such ratios are measured at the primary energy stage and should instead be estimated at the final stage where energy enters the economy (for example, electricity and petrol). Here, we calculate global time series (1995–2011) energy-return-on-investment ratios for fossil fuels at both primary and final energy stages. We concur with common primary-stage estimates (~30:1), but find very low ratios at the final stage: around 6:1 and declining. This implies that fossil fuel energy-return-on-investment ratios may be much closer to those of renewables than previously expected and that they could decline precipitously in the near future
An assessment of the J-integral test for a metallic foam
An assessment is made of the J-integral test procedure for initial crack
growth in an open-cell aluminium alloy foam by combining finite element (FE)
simulations with experiment. It is found experimentally that a zone of randomly
failed struts develops ahead of the primary crack tip, and is comparable in
size to that of the plastic zone. Hence, a crack tip J-field is absent at the
initiation of crack growth from the primary crack tip. This implies that the
measured J_IC value and the J versus crack extension Da curve cannot be treated
as material properties despite the fact that the specimen size meets the usual
criteria for J validity. The toughness tests were performed on a single-edge
notched bend specimen, and crack extension was measured by the direct current
potential drop method, by digital image correlation and by X-ray computed
tomography. The crack growth resistance of the foam is associated with two
distinct zones of plastic dissipation: (i) a bulk plastic zone emanating from
the crack tip (containing a cluster of randomly failed struts), and (ii) a
crack bridging zone behind the advancing crack tip. The applicability of a
cohesive zone model to predict the fracture response is explored for the
observed case of large scale bridging. To do so, FE simulations are performed
by replacing the discrete lattice of the open-cell metallic foam by a
compressible, elastic-plastic hardening solid while the fracture process zone
in the foam is represented by a cohesive zone, as characterised by a tensile
traction versus separation law. A detailed comparison of the cohesive zone
model with experimental observations reveals that it is possible to capture the
load versus displacement response but not the details of the fracture process
zone using a single set of process zone parameters
EFFECT OF TAO-HONG-SI-WU-TANG, A TRADITIONAL CHINESE HERBAL MEDICINE FORMULA, ON PHYSICAL FATIGUE IN MICE
Tao-Hong-Si-Wu-Tang (THSWT) is a famous traditional Chinese herbal medicine formula, which has traditionally been used in China for about one thousand years. The present study investigated the effect of THSWT on physical fatigue. 32 male mice were randomly divided into 4 groups with 8 in each group. All were administered orally and daily for 28 days. Group I received isotonic saline solution as control; Group II, III and IV obtained 5, 10 and 20ml/ kg body weight of THSWT solutions, respectively. After 28 days, the anti-physical fatigue effect of THSWT was evaluated by using a forced swimming test, along with the determination of blood lactic acid, blood urea nitrogen (BUN), liver glycogen and muscle glycogen contents. The data showed that THSWT could extend exhaustive swimming time of mice, as well as decrease the BLA and BUN contents and increase the liver glycogen and muscle glycogen contents. The results support that THSWT had anti-physical fatigue effect
Synchronous primary intrapulmonary and mediastinal thymoma-A case report
We report an extremely rare case of Synchronous primary intrapulmonary and mediastinal thymoma in a Chinese patient. We describe the histological and radiological findings, which support the possibility of multicentric thymoma. Resection of the mass in the left anterior superior mediastinum and upper lobectomy of right lung were performed, with lymph Nodes clearance, superior vena cava, left and right brachiocephalic veins resection, reconstruction of left brachiocephalic vein to right auricle and reconstruction of right brachiocephalic vein to superior vena cava
Culture clash: Appearance concerns in black and minority ethnic groups
Around the world, men and women of all cultures and ethnicities are being exposed to Western appearance ideals. Paired with a lack of representation of black and minority ethnic (BME) men and women in the mainstream media, the public's appreciation of ethnic diversity is being threatened. Nicola Stock examines the growing trend of appearance-altering practice among those from BME communities
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