23 research outputs found
Mechanical activation and thermodynamic destabilization of the lithium amide and lithium hydride system
No full textThe practical application of hydrogen storage in fuel cells for transportation purposes in hydrogen powered vehicles has been one of the major challenges. Complex metal hydrides have been considered as potential materials for practical on-board hydrogen storage applications because of their reversible storage and release of hydrogen, and moderately high gravimetric and volumetric hydrogen capacities. Within the last decade, the Li-N-H or (LiNH2+LiH) system has been investigated intensively as a candidate for practical on-board hydrogen storage. Despite of its reversible storage reaction with a theoretical capacity of 6.5 wt. % H2, there are two primary issues that prevent the utilization of this system for the on-board hydrogen storage: (1) the NH3 emission and (2) a relatively high operating temperature (∼280°C) for reversible hydrogen absorption and desorption at 1 bar of H2. ^ The NH3 emission results in hydrogen fuel contamination which can damage the PEM fuel cells and consequently degrade the hydrogen storage capacity. The utilization of the mechanical activation via the high-energy ball milling has been shown to be an effective way to address the NH 3 emission issue. This is due to the decrease in particle and crystallite size, increase in surface area, and better mixing of LiNH2 and LiH. The dehydriding reaction of the (LiNH2+LiH) mixture was also substantially enhanced by high-energy ball milling. The peak temperature for releasing large amounts of H2 from the mixture was reduced by ∼ 100°C via ball milling at room temperature for 180 min. ^ To lower the hydrogen absorption and desorption temperatures further and increase the H2 equilibrium pressure of the (LiNH2+LiH) system, the thermodynamic destabilization of the lithium amide through partial substitution of Li by Mg in lithium hydride has been pursued and confirmed that the (2LiNH 2+MgH2) mixture has a higher thermodynamic driving force for dehydrogenation than the (LiNH2+LiH) mixture, as reported by many other studies. This higher thermodynamic driving force results in a lower onset temperature for the dehydrogenation of the (2LiNH2+MgH 2) mixture than that of the (LiNH2+LiH) mixture. Furthermore, the isothermal hydriding and dehydriding cycling performance of the Li-Mg-N-H (1:2) system, starting with Li2MgN2H2 at 200°C has been examined in this study. This system exhibits a slow hydriding rate controlled by diffusion and a fast dehydriding rate that exhibits two distinct stages consisting of a very fast release at the beginning followed by a slow release. The hydriding and dehydriding reaction pathways during the cycling have been proposed.
Inorganic additives for passivation of high voltage cathode materials
No full textThe incorporation of additives designed to sacrificially react on the surface of cathode materials of lithium ion batteries has been investigated. Addition of low concentrations of inorganic additives including lithium bisoxalatoborate (LiBOB), lithium difluorooxalatoborate (LiBF2(C 2O4)), and tetramethoxy titanium (TMTi) to 1 M LiPF 6 in 1:1:1 EC/DEC/DMC improves the capacity retention of Li/Li 1.17Mn0.58Ni0.25O2 cells cycled to 4.9 V vs. Li. Surface analysis of the cathode materials (XPS and IR) suggests that structure of the cathode surface film is modified by the presence of the additives resulting in a decrease in detrimental electrolyte oxidation reactions on the cathode surface. © 2010 Elsevier B.V. All rights reserved
Cathode Solid Electrolyte Interphase Generation in Lithium-Ion Batteries with Electrolyte Additives
No full textThe incorporation of additives designed to sacrificially react on the surface of cathode materials of lithium ion batteries has been investigated. Addition of low concentrations of either organic (2,5-dihydrofuran (2,5-DHF) or γ-butyrolactone (GBL)) or inorganic additives (lithium bisoxalatoborate (LiBOB), lithium difluorooxalatoborate (LiBF2(C2O4)), tetramethoxytitanium (TMTi), and tetraethoxysilane (TEOS)) to 1 M LiPF6 in 1:1:1 EC/DEC/DMC improves the capacity retention of Li/ Li1.17Mn0.58Ni0.25O2 cells cycled to 4.9 V vs Li.</jats:p
Inhibition of electrolyte oxidation in lithium ion batteries with electrolyte additives
No full textThe incorporation of additives designed to sacrificially react on the surface of cathode materials of lithium ion batteries has been investigated. Addition of low concentrations of various additives to 1 M LiPF6 in 1:1:1 EC/DEC/DMC improves the capacity retention of Li/Li1.17Mn0.58Ni0.25O2 cells cycled to 4.9 V vs Li. Surface analysis of the cathode materials (XPS and IR) suggest that structure of the cathode surface film is modified by the presence of the additives resulting in a decrease in detrimental electrolyte oxidation reactions on the cathode surface. Film forming mechanisms and structures will be discussed
Abiding by the sufficiency economy philosophy to develop the quality of life of teachers and educational personnel in the central region
No full textPublic and private partnerships in strengthening vocational education and training
No full textDissertation (Ph.D. (Development Administration))--National Institute of Development Administration, 2015This paper draws on the theoretical concepts from Inter-organizational
relations theory, public governance, and public and private partnerships (PPPs), which
are incorporated with the conceptions learned from the two cases of PPPs in technical
vocational education and training in Singapore and the U.S. As a result, an initial
conceptual framework was developed to guide in the understanding of the public and
private partnership phenomenon. The framework includes a broad conceptualization
of public and private partnerships, consisting of the following domains: initial
conditions and motives, structure and governance, the partnership process, and
partnership capabilities.The objectives of the study include: 1) identifying the motives of the
collaborating actors in initiating public and private partnerships for vocational
education and training; 2) exploring the institutional settings of the PPPs in terms of
governance and structure; 3) identifying the factors critical for sustaining successful
public and private partnerships for vocational education and training; and 4)
developing a conceptual framework in order to understand and assess public and
private partnerships for vocational education and training.The author has chosen the case study research method, an inductive, caseoriented
process of theory development, to investigate the in-depth phenomenon and
rich context of public and private partnerships, which are regarded as a new topic area
within the organizational theories arena. The unit of analysis for this study is the
partnerships among relevant partners agreeing to implement an initiative in
strengthening vocational education and training. The multiple case study approach was used as the research design. Therefore, the author collected the data and analyzed
them within the cases and compared them across different cases with different
contexts.In this study, the author selected three cases of leading vocational education
and training implemented in Thailand. They are: 1) the Automotive Human Resource
Development Academy, 2) a Work-Integrated Learning program, and 3) German-Thai
Dual Excellence Education. These three cases are different in terms of the
combination of partnering agencies, sponsoring organization, and key players
contributing to the success of the partnerships. The collected information included
qualitative data derived from documentation, archival records, participant
observation, and in-depth interviews with the 24 key informants selected from the
three cases.The conceptualization of the public and private partnerships is presented in
two stages, before and during PPP formation. Prior to the PPP formation, vulnerable
strategic conditions existed. The convener of the PPP, who is highly regarded as a
respectable figure with access to resources, assembles potential partners, agreeing that
urgent action is needed to address the issue. They all shared common values in
treating the shared goals of public interests as a high priority. The contingencies of
reciprocity and effectiveness are prompted by these shared benefits. During PPP
formation, the convener or the party with higher political power will influence how
the partnership is structured and governed. The contingency of asymmetry leads to the
formation of partnerships, which is usually influenced by the partner with superior
negotiating power. It is essential that this coordination unit possess cooperative
capabilities, especially regarding relationship management skills, in order to
effectively liaise with the partners to undertake the planned activities successfully.The author has proposed four strategies to forster successful public and private
partnerships in order to efficienty synergize resources for tackling public issues.
These strategies include: 1) building awareness of public and private partnerships and
a collaborativeon mindset; 2) engagement of the private sector as part of the
governance of public service delivery; 3) promotion of PPPs through a funding and
incentive mechanism with government oversight on the quality control of the awarded
programs; and 4) building government capacity regarding cooperative capabilities
Sphingius gracilis Thorell 1895
No full textSphingius gracilis (Thorell, 1895) Figure 2 Thamphilus gracilis Thorell: Thorell, 1895: 36; description of female. Sphingius gracilis (Thorell): Simon, 1897: 158. Deeleman-Reinhold, 2001: 489, figs 837–838. Scotophaeoides sinensis Schenkel: Schenkel, 1963: 49, fig. 24; description of female. Song, Zhu & Zhang, 2004: 209, figs 124 A– C. Murphy, 2007: 589, figs 596–597. Syn. nov. Sphingius sinensis (Schenkel): Zhang Fu & Zhu, 2009, 38, figs 13–20. Type material. Holotype, Scotophaeoides sinensis Schenkel: ♀, CHINA: Cantong (modern formal spelling = Guangdong), (MNHN AR- 3109, examined). Other material. Thamphilus gracilis Thorell: MYANMAR, Palon: 1885-1889, leg. L. Fea, 2 ♀ (MSNG, examined). Original label: Thamphilus gracilis Thor. Birmania: Palon. Fea. Remarks. The first author was unable to locate a female holotype of Thamphilus gracilis Thorell, 1895 collected from Tharrawaddy and subsequently deposited in the collection of NMHL during his visit. Fortunately, the type was previously studied by Deeleman-Reinhold (2001) who transferred it to Sphingius and provided sketches of the epigyne and internal genitalia. Two females collected from Palon which were identified as T. gracilis by Thorell himself (deposited at MSNG) are the base of our study (Fig. 2). Zhang et al. (2009) transferred Scotophaeoides sinensis Schenkel, 1963 (misplaced in Gnaphosidae) to Sphingius. The female holotype of Sc. sinensis closely resembles females of T. gracilis in having very similar general appearance and genitalic structures (see also Murphy 2007; Zhang et al. 2009). The difference between S. gracilis and S. sinensis is the broader proximal portion of insemination ducts in the latter species but this is likely an intraspecific variation. Distribution. Myanmar and China (Guangdong, Guangxi).Published as part of Dankittipakul, Pakawin, Tavano, Maria & Singtripop, Tippawan, 2011, Neotype designation for Sphingius thecatus Thorell, 1890, synonymies, new records and descriptions of six new species from Southeast Asia (Araneae, Liocranidae), pp. 1-20 in Zootaxa 3066 on pages 17-18, DOI: 10.5281/zenodo.20192
