550 research outputs found
First look at the physics case of TLEP
No full textFirst appraisal of the physics potential of a future electron-positron collider (TLEP) at the TeV scale, after the discovery of the Higgs boson at the LHC. Report of the TLEP Design Study Working Group
Mobility mining for journey planning in Rome
No full textWe present recent results on integrating private car GPS routines obtained by a Data Mining module. into the PETRA (PErsonal TRansport Advisor) platform. The routines are used as additional “bus lines”, available to provide a ride to travelers. We present the effects of querying the planner with and without the routines, which show how Data Mining may help Smarter Cities applications
One-step fabrication of new generation graphene-based electrodes for polymer electrolyte membrane fuel cells by a novel electrophoretic deposition
No full textHigh Pt loading has better tradeoff in polymer electrolyte membrane fuel cell (PEMFC) in terms of improved performance and operational longevity. But, to employ low amounts of Pt electrocatalysts via an alternative carbon-based support and utilization technique is vital. This study presents the use of a one-step novel technique, an electrophoretic deposition (EPD) method, through which reduced graphene oxide (rGO) supported Pt nanoparticles have been directly fabricated onto carbon paper to form electrodes for PEMFC. Our process involves simultaneous synthesis and deposition of Pt-reduced GO nanocomposites onto oxygen plasma pre-treated carbon paper in an organo-aqueous media at various deposition time. Through this technique, homogenously distributed Pt nanoparticles ranging from 5 to 6 nm in size on graphene support were successfully synthesized to form catalyst layer on carbon paper. The characteristics of fabricated electrodes were investigated ex-situ by Raman spectroscopy, FE-SEM, XPS, ICP, FIB, TEM. Furthermore, catalytic activity towards hydrogen oxidation reaction was evaluated via CV measurements and fuel cell performance tests were also conducted. The highest ECSA value of 27.4 m2g-1 and the Pt utilization efficiency of 1.48 kW/gPt−1 were achieved at an optimized Pt loading of 0.129 mg cm−2. A maximum power density of 280 mW cm−2 was obtained with increasing EPD time and Pt precursor concentration at the same time. The achieved results are attributed to the dispersion of Pt nanoparticles on rGO nanosheets displaying synergetic performance as catalyst necessary for PEMFCs, thanks to the EPD technique's viability, ease in handling, and reproducibility in the synthesis route. In the previous studies on Pt/GO based fuel cell electrodes by EPD, on one hand, Pt NPs were synthesized on GO by chemical methods first and electrodes were fabricated by a subsequent EPD. On the other hand, the fuel cell performances of those electrodes have been rarely shown. To the best of our knowledge, this is the first time in literature not only about the use of EPD technique for the fabrication of fuel cell electrodes in one-step but also the evaluation of fuel cell performance of the electrodes fabricated by EPD
One-step anion-assisted electrodeposition of ZnO nanofibrous networks as photoanodes for dye-sensitized solar cells
No full textA highly efficient ZnO photoanode consisting of three-dimensional (3D) nanofibrous-like networks (NFs) for dye-sensitized solar cells (DSSCs) was synthesized using a one-step and seed-layer-free electrodeposition on an indium-tin-oxide (ITO) substrate at 75 degrees C in a solution containing Zn(NO3)(2), KCl, NaCH3COO, and Na3C6H5O7. In this solution, KCl as the supporting electrolyte promotes the reduction of NO3- and the diffusion of Zn2+, whereas CH3COO- and C6H5O73- anions act as the capping agents to selectively inhibit ZnO growth along the c-axis. The photoelectrochemical results reveal that the DSSC based on ZnO NFs has the highest power conversion efficiency (3.78%) in comparison with those of DSSCs based on nanosheets (1.36%), nanorods (2.18%), and microplates (2.55%). This can be attributed to the large dye adsorption amount, efficient light scattering and direct electron transfer networks, which lead to a significant improvement in solar cell performance. Therefore, the ZnO NFs structure can be considered as a promising and efficient photoanode for DSSCs
Mathematics Achievement in the Secondary High School Context of STEM and non-STEM Schools
No full textThe primary purpose of the research conducted during this dissertation study is to explore how students who attended ISHSs performed on the mathematics high-stakes state test compared to their corresponding peers who attended traditional public high schools in Texas. All three studies included in this dissertation used quantitative data
(i.e., state standardized test scores) to investigate whether students��� mathematics performance differs by high school types: STEM and non-STEM. The research for the first article employed one year of state-based data and focused on the comparison of
STEM and non-STEM high schools in terms of students��� mathematics achievement. The second article employed a longitudinal assessment of students��� mathematics achievement to observe how students��� initial mathematics scores and their growth rate differ by their high school type as STEM and non-STEM. Research conducted for the third article also used longitudinal state-based data to examine how Hispanic students��� mathematics achievement in ISHSs compares to their Hispanic counterparts in traditional public schools.
Results from the first study revealed that Hispanic students who participate in TSTEM academies statistically significantly (p < .05) performed better in mathematics at the end of grade 11 than did Hispanic students who participated in traditional public high schools when controlling for gender and SES. The second study revealed female students��� mathematics growth rate in T-STEM academies was statistically significantly higher than female students��� mathematics growth rate in traditional public high schools controlling for ethnicity and SES. The third study���s findings indicated that female Hispanic students in T-STEM academies statistically significantly (p < .05) outperformed female Hispanic students in comparison schools on their mathematics growth rate.
Overall, results from this dissertation study yielded that T-STEM academies are most helpful for Hispanic students, and especially for female Hispanic students, in Texas. The findings of this dissertation are important because increasing the number of underrepresented students who major in STEM, which is needed to maintain the United States��� scientific leadership and economic power in the global world, can be possible by establishing more inclusive STEM schools in high Hispanic populace locations
Cavity Ring-Down Spectroscopy of Trace Components in Gas Mixtures for Breath Analysis and Environmental Applications
No full textCavity ring-down spectroscopy (CRDS) is a direct absorption technique, which provides
high detection sensitivity of gas, liquid or solid phases. By using high reflectivity mirrors, the
effective absorption path length can be increased up to the hundred-kilometer range. In this
work, a single mode tunable CW laser source was used to achieve high sensitivity detection with
a narrow line width. The light source is a distributed feedback (DFB) diode laser. By changing
the temperature and the current of the diode laser, the output wavelength was tuned across the
absorption line peaks of carbon dioxide, methane (COv2, CHv4) and acetone (CHv3COCHv3). In
particular, the main goals of this study are the optimization of the detection sensitivity of the
isotope ratio (^13C/^12C) of indoor COv2 and CHv4, exhaled acetone analysis for diagnosing diabetes
and studying of the gas content of natural water. In this study, first, the ^13C/^12C ratio of COv2 and
CHv4 for room air will be discussed. Second, the results on acetone absorption spectrum for
diabetic and non-diabetic people will be presented. Third, a membrane gas separation system and
spectroscopic analysis of gas content will be described
RILEM TC 277-LHS report: properties of lime-based renders and plasters—discussion of current test methods and proposals for improvement
No full textRenders and plasters have significant functions in buildings. Their functionality is closely related to their properties, which depend on the mortar itself, the application technology, the interaction with the environment and the substrate. There are many basic characteristics that influence the performance of renders and plasters; however, many of them are interrelated, thus the set of characteristics to be determined in each case is different, depending on the specific at each time use. These characteristics, their interrelations and the grouping of them are discussed and schematically described in the first and introductory section. Three groups are considered for renders and plasters: properties of fresh mortars; properties related to the hygric behaviour; and the mechanical behaviour. The properties of lime-based mortars measured in laboratory are highly affected by factors, such as: need of long time for development of representative values for prediction of their life-time behaviour, proper climatic conditions adequate for carbonation or/and hydration, sensitivity to the suction of water by the substrate. The last two factors—environment and substrate—have an important role for rendering and plastering with lime-based mortars, since both their exposed surfaces and the substrate areas they cover are large. Due to those specificities, the current test methods that have been mainly developed for cement-based mortars are not always fitted to characterize lime-based mortars, and in particular to assess lime-based renders and plasters. In section two the main characteristics and current standardized test methods are discussed based on experience in using them. Furthermore, needs of improvement are identified and changes are proposed, or, in some cases, new methods are outlined. Some of the most significant changes proposed are the possibility, as an option, to apply the mortar on a porous substrate, instead of moulding specimens in metallic moulds, together with modifications on curing conditions and times of mixing and testing. Additionally, test methods developed at laboratory to evaluate the cracking tendency due to restrained shrinkage and to determine the modulus of elasticity of under checking mortars are proposed, as well as alternative test methods for adhesion. In the case of testing other properties, smaller changes are proposed, in order for the standardized test methods to be adapted to the particularities of lime-based renders and plasters. As conclusions, in the third section, a synthesis of the proposed changes and complementary tests has been made in formulated tables, that could be considered as a first approach of adapted requirements for better performance of lime-based mortars for renders and plasters
First Look at the Physics Case of TLEP
No full textThe discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e+e- collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for top-quark, Higgs boson, W and Z studies, accommodates multiple detectors, and can reach energies up to the\mathrm{t}\overline{\mathrm{t}} threshold and beyond. It will enable measurements of the Higgs boson properties and of Electroweak Symmetry-Breaking (EWSB) parameters with unequalled precision, offering exploration of physics beyond the Standard Model in the multi-TeV range. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. Altogether, the combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market. This paper presents a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study. [Figure not available: see fulltext.] © 2014 SISSA, Trieste, Italy
Constructing the metropolitan homeland: the literatures of the white settler societies of New Zealand and Australia
No full textThis article examines the responses articulated in white settler writing from New Zealand and Australia to the location and status of these nations as postcolonial diasporas. Beginning with the early colonial sense of estrangement from and idealisation of the metropolitan homeland of Great Britain it traces a pattern of literary engagement with the European source of ethnic origin through to the present day. The article notes changing attitudes towards home and homelands due to the greater fluidity and complexity of migratory and travel paths as the binaries of home and abroad, empire and colony, metropolitan centre and provincial periphery begin to break down towards the end of the twentieth centur
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