共查询到7条相似文献,搜索用时 15 毫秒
1.
Hydrogen storage: The major technological barrier to the development of hydrogen fuel cell cars 总被引:2,自引:0,他引:2
In this paper, we review the current technology for the storage of hydrogen on board a fuel cell-propelled vehicle. Having outlined the technical specifications necessary to match the performance of hydrocarbon. fue1, we first outline the inherent difficulties with gas pressure and liquid hydrogen storage. We then outline the history of transition metal hydride storage, leading to the development of metal hydride batteries. A viable system, however, must involve lighter elements and be vacuum-tight. The first new system to get serious consideration is titanium-activated sodium alanate, followed by the lithium amide and borohydride systems that potentially overcome several of the disadvantages of alanates. Borohydrides can alternatively produce hydrogen by reaction with water in the presence of a catalyst but the product would have to be recycled via a chemical plant. Finally various possible ways of making magnesium hydride decompose and reform more readily are discussed. The alternative to lighter hydrides is the development of physisorption of molecular hydrogen on high surface area materials such as carbons, metal oxide frameworks, zeolites. Here the problem is that the surface binding energy is too low to work at anything above liquid nitrogen temperature. Recent investigations of the interaction mechanism are discussed which show that systems with stronger interactions will inevitably require a surface interaction that increases the molecular hydrogen-hydrogen distance. 相似文献
2.
C. Tötzke I. MankeT. Arlt H. MarkötterN. Kardjilov A. Hilger S.H. WilliamsP. Krüger R. KuhnC. Hartnig J. ScholtaJ. Banhart 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2012,663(1):48-54
We present two different methods to increase the size of available neutron beams in order to allow for the investigation of large objects. Application of these methods is demonstrated for radiographic imaging of fuel cells. The first approach is a scanning procedure based on the coordinated translation of detector and sample through the beam. Further advancement was achieved by installing a focusing neutron guide, which offers an expanded neutron beam size after diverging from a focused point source. 相似文献
3.
In order to protect bolts from corrosion, electroplating such as zinc plating is widely used. However, hydrogen can easily penetrate or diffuse into the vacancies and dislocations between the lattices of bolt steel during electroplating. As the diffused hydrogen defects inside the lattice are in gaseous form, small cracks can easily be produced due to high pressure from the hydrogen gas. In this research, in order to determine the root cause of the fracture in pole fastening screws resulting from hydrogen embrittlement in typical electric motors, additional factors that accelerate hydrogen embrittlement fracture were selectively applied, including a small fillet in the head–shank transition and excessive hardness, and parametric study was performed experimentally. 相似文献
4.
There is tremendous worldwide interest in functional nanostructured materials, which are the advanced nanotechnology materials with internal or external dimensions on the order of nanometers. Their extremely small dimensions make these materials unique and promising for clean energy applications such as lithium ion batteries, supercapacitors, hydrogen storage, fuel cells, and other applications. This paper will highlight the development of new approaches to study the relationships between the structure and the physical, chemical, and electrochemical properties of functional nanostructured materials. The Energy Materials Research Programme at the Institute for Superconducting and Electronic Materials, the University of Wollongong, has been focused on the synthesis, characterization, and applications of functional nanomaterials, including nanoparticles, nanotubes, nanowires, nanoporous materials, and nanocomposites. The emphases are placed on advanced nanotechnology, design, and control of the composition, morphology, nanostructure, and functionality of the nanomaterials, and on the subsequent applications of these materials to areas including lithium ion batteries, supercapacitors, hydrogen storage, and fuel cells. 相似文献
5.
《Materials at High Temperatures》2013,30(2):233-239
AbstractBoth the US Department of Energy (DOE) and EPRI are developing models for the evolution of a secure energy future for the USA. Our general views are very similar. However, there are some differences in approach. DOE is concerned with all energy issues in the US future, including electricity, transportation fuels, and the industrial, commercial, and residential energy sectors; EPRI is concerned specifically with the electricity component, principally in the USA, but, as does DOE, also takes a global view.Both organizations take what is now known as a ‘Roadmapping’ approach. Roadmapping is an example of a ‘Top Down’ planning method: it involves the specification of a “destination” which the research and development program is aimed towards. In the DOE case, the destination refers to a secure energy future. Typically, Roadmapping is concerned with relatively long time scales. Time scales for different technologies are, of course, very different; in a fast-moving technology such as semiconductors, five to ten years may be a long time. For energy, the equipment is large; planning and construction times are long, and the expected lifetimes of the major components are not less than twenty years, and more typically up to forty years. The time scale that both of our organizations talk about is in the range 20–50 years in the future. The DOE model is called ‘Vision 21.’ The specific destination for Vision 21 is the technical design bases for near-zero emission fossil fueled energy plants. The EPRI model is called the ‘Electricity Technology Roadmap’, and more recently we have ‘A Vision of the Electricity System of 2020.’ An important aspect of the method common to both DOE and EPRI is that the destination is developed by what is called a ‘Stakeholder’ group: this involves not only the researchers and developers, but also the eventual customers for the technology, and the users of the products. This will include members with environmental and societal concerns.In this paper, we will highlight some of the scenarios that emerge from these models. The first part will concentrate on the Department of Energy program; the latter part on the EPRI view, remembering that we are in close agreement on most aspects. 相似文献
6.
This paper links the industrial policy and national systems of innovation literature to the investigation of learning capabilities of suppliers in the context of the automotive parts industry of Pakistan. Drawing data from 50 Pakistani autoparts suppliers, the findings suggest that industrial policy has been helpful in creating a local parts supply base and facilitating the entry of Japanese assemblers in the market. However, the implementation of the policy has been weak, and it is an arduous journey for the local suppliers to develop ambidextrous (exploratory and exploitative) learning capabilities. The findings also indicate that where local training and support from R&D institutions are weak, networking alone with foreign multinationals is not sufficient on its own to develop exploratory learning capabilities of local suppliers. This paper shows the importance of creating national–provincial institutions offering learning and skills development aimed towards innovation. 相似文献
7.
Laura Tirkkonen Heidi Halonen Jari Hyttinen Hannu Kuokkanen Harri Siev?nen Anna-Maija Koivisto Bettina Mannerstr?m George K. B. Sándor Riitta Suuronen Susanna Miettinen Suvi Haimi 《Journal of the Royal Society Interface》2011,8(65):1736-1747
Mechanical stimulation is an essential factor affecting the metabolism of bone cells and their precursors. We hypothesized that vibration loading would stimulate differentiation of human adipose stem cells (hASCs) towards bone-forming cells and simultaneously inhibit differentiation towards fat tissue. We developed a vibration-loading device that produces 3g peak acceleration at frequencies of 50 and 100 Hz to cells cultured on well plates. hASCs were cultured using either basal medium (BM), osteogenic medium (OM) or adipogenic medium (AM), and subjected to vibration loading for 3 h d–1 for 1, 7 and 14 day. Osteogenesis, i.e. differentiation of hASCs towards bone-forming cells, was analysed using markers such as alkaline phosphatase (ALP) activity, collagen production and mineralization. Both 50 and 100 Hz vibration frequencies induced significantly increased ALP activity and collagen production of hASCs compared with the static control at 14 day in OM. A similar trend was detected for mineralization, but the increase was not statistically significant. Furthermore, vibration loading inhibited adipocyte differentiation of hASCs. Vibration did not affect cell number or viability. These findings suggest that osteogenic culture conditions amplify the stimulatory effect of vibration loading on differentiation of hASCs towards bone-forming cells. 相似文献