Miracle-dz/UniFAR-FTUs huggingface dataset:
Modelado de la combustión de mezclas gasolina-etanol en motores de combustión interna.

Este trabajo analiza el efecto que tiene el cambio de combustibles tradicionales por combustibles oxigenados (que contienen etanol) sobre la temperatura del proceso de combustion en motores de combustion interna encendidos por chispa. Ademas de esto se investiga el impacto de otras variables de funcionamiento como el tiempo de encendido, la relacion de combustible-aire equivalente y la relacion de compresion. Para llevar esto a cabo se realizo una labor de experimentacion y simulacion. Para el primero se ejecutan pruebas sobre un motor CFR utilizando diferentes mezclas de gasolina-etanol, registrando como minimo los parametros exigidos en la NTC 1930, mas la senal de presion de la camara de combustion. Para la simulacion se desarrollo un modelo unidimensional basado en la teoria de propagacion turbulenta de llama, planteada originalmente por Blizard y Keck [132]. A este modelo se le introdujeron modificaciones para poder utilizar mezclas de gasolina con etanol. Los principales cambios incluyen sub-modelos nuevos para la velocidad laminar de llama, para la velocidad promedio a traves de la valvula y para la eficiencia de combustion. Los resultados indican que la temperatura de combustion aumenta con el cambio de combustible siempre y cuando la velocidad promedio a traves de la valvula y la eficiencia de combustion sean mayores que las del caso con gasolina pura. Estos dos factores se pueden presentar cuando se utilizan mezclas gasolina-etanol, debido a la mayor densidad en la mezcla durante la admision y al mejor quemado del combustible por una liberacion mas alta de radicales libres durante el proceso de combustion. / Abstract: This paper analyzes the effect of changing fuels by oxygen (containing ethanol) on the temperature of the combustion process in internal combustion engines ignited by spark. In addition to this we investigate the impact of other operating variables such as ignition timing, the fuel-air ratio of charge and the compression ratio. To accomplish this work was carried out experimentation and simulation. For the first run on a CFR engine tests using different blends of gasoline-ethanol, recording at least the standards set by the NTC 1930, more pressure signal of the combustion chamber. To simulate one-dimensional model was developed based on the theory of turbulent flame propagation, originally raised by Blizard and Keck [132]. This model was introduced modifications to use ethanol-gasoline blends. The major changes include new sub-models for the laminar flame speed for the average speed through the valve and combustion efficiency. Results indicate that the combustion temperature increases with fuel switching as long as the average velocity through the valve and combustion efficiency are greater than the case with pure gasoline. These two factors may occur when using gasoline-ethanol blends, due to increased density in the mix at admission and better fuel burned by a higher release of free radicals during the combustion process.
Teachers’ Engagement in Workplace Learning Activities: Validation of a Measure

Quantitative research into the topic of workplace learning among teachers has been limited due to the lack of measures that are applicable to the educational sett ings. In this study, items measuring teachers’ engagement in workplace learning activities were generated through literature review and discussions with schoolteachers; selected by the authors; and then tested in a fi eld study. The sample involved a total of 500 schoolteachers, selected through a multistage cluster sampling procedure. Exploratory and confi rmatory factor analyses were used to test the hypothesised two-dimensional model for the construct of engagement in workplace learning activities. Results indicated that the proposed model acceptably fi ts the data and the loadings were all signifi cant at p<. 05, thus lending evidence for the construct validity of the instrument. Implications for the use of this scale in future workplace learning research, particularly in the educational sett ings, are discussed.
Hierarchical NiCo2O4 nanowire arrays on Ni foam as an anode for lithium-ion batteries

A facile two-step method is developed for large-scale growth of hierarchical mesoporous NiCo2O4 nanowire arrays on Ni foam with robust adhesion as a high performance electrode for lithium-ion batteries (LIBs). The as-prepared mesoporous NiCo2O4 nanowire arrays consist of numerous highly crystalline nanoparticles, the Ni foam supported NiCo2O4 nanowires promote fast electron and ion transport, and alleviate the volume change during the charge–discharge processes. When evaluated as a binder-free electrode for LIBs, the NiCo2O4 electrode exhibits a greatly enhanced charge capacity of 1520 mA h g−1 at a current density of 100 mA g−1. The mesoporous NiCo2O4 nanowire arrays exhibit great potential as an anode material for LIBs with the advantages of unique performance and facile preparation.
Compilation of Wavelengths, Energy Levels, and Transition Probabilities for W I and W II

Energy levels, wavelengths, and transition probabilities of the first and second spectra of tungsten, W I and W II, have been compiled. Wavelengths of observed transitions and energy levels derived from those wavelengths have been obtained from a critical evaluation of the available literature. Measured transition probabilities for some of the observed transitions have been compiled from the published literature.
Self-diffusion and shear viscosity of simple fluids. A molecular-dynamics study

Extensive molecular-dynamics, MD, simulations of Lennard-Jones, LJ, and soft-sphere, SS, fluids have been made. The LJ state points agree excellently with the predictions of a recent equation of state for this fluid. Self-diffusion coefficients obtained from the LJ mean-square displacements at equilibrium are fitted to a simple analytic expression, involving temperature and density, which has a density and temperature range of wider applicability than that of Levesque and Verlet. The corresponding shear viscosities in the limit of zero shear rate have been obtained by a new non-equilibrium MD technique, which involves orthogonal longitudinal distortions (eliminating pure expansion or compression terms). The LJ shear rigidity moduli are fitted to better than 1 % by a simple analytic expression. A similar relationship for the shear viscosities is less satisfactory but this merely reflects the greater uncertainty in this collective transport property. The Stokes–Einstein relationship using slip boundary conditions gives an effective ‘flow unit’ diameter which decreases from several molecular diameters to one as the density increases. This suggests that the motion between a molecule and those in its first coordination shell is more cooperative at moderate densities resulting in greater coupling between molecular trajectories. Support for this comes from the direct evaluation of the friction coefficient by non-equilibrium MD, pair radial and pair fluctuation correlation functions.The Verlet algorithm was used in these calculations. The more accurate Toxvaerd algorithm is shown not to improve noticeably the accuracy of the systematic component of single (and hence possibly collective) particle motion, as measured by velocity and force autocorrelation functions.
EXPERIMENTAL THERMAL BURNS, ESPECIALLY THE MODERATE TEMPERATURE BURN

I. With the object of producing standard low-temperature burns in animals, and of studying the area of tissue only partly damaged in a burn, a burning iron has been made capable of applying temperatures from 45°-80°C. to the skin; with this the amount of heat and temperature causing skin damage has been studied, and the macroscopic and microscopic damage due to graded temperatures have been delineated. II. Macroscopic Changes. 1. Graded temperatures of 45°-80°C. have been applied to the skin of shaved, anaesthetised guinea-pigs, and in some cases rats, for times varying from 10 sec. to 6 and 10 min. Observations have been made of the development of erythema, flare, blanching, blueing, heat fixation, incipient blister formation, œdema, and edge wheal, as also upon the later scab formation and rate of epithelium regeneration. 2. Applications of 47°C. up to 6 minutes produce no visible change. 3. At 50°-55°C. applied for 1 minute and over, there is a critical temperature for the development of permanent and irreversible damage; in animals good scab formation occurs after burning at this temperature. 4. After temperatures of 60°-65°C. the epidermis can be peeled off from the exposed area, leaving a punched-out exposed surface area somewhat like the exposed human blister. 5. A temperature of 70°-80°C. for 10-20 seconds produces severe scabbing. 6. Observations of œdema formation have been checked by wet and dry weights of specimens of skin taken 2 hours after heating. At 55°C. there is some change, but this is more definite at 60°C. 7. The observations recorded here are readily reproducible and provide a standard method of burning for experimental work. III. Microscopic Changes. 1. The histological effects of mild burns of varying intensity and duration have been described in detail. They follow the general picture previously recorded in necrotic changes. 2. Two different types of reaction are described; with milder burns there is cellular disintegration; with more intense burns, heat coagulation. 3. In more intense burns there is a peripheral shell of changes characteristic of burns of lower temperature. 4. Two substances are lost by the epithelium of skin which has been subjected to a burn: (a) Basophil granules from the cytoplasm. (b) Nucleoprotein from the nuclei. These two substances can be identified in the intercellular blister spaces. 5. Collagen fibres change in structure and staining affinity in the more intense burns. Our thanks are due to the Carnegie Trustees for a personal grant to one of us (R. J. Rossiter); to the Nuffield Committee and Trustees and to the Medical Research Council for grants which have helped the cost of this research, though this has been also much financed from University sources. We are grateful to Dr. M. C. Manifold for help with some of the preliminary observations and to Dr. A. N. Drury, Dr. L. Colebrook, and Mr. E. Rock Carling for their interest. We also wish to thank Mr. Marsden for technical assistance with the histology.
Effect of collector‐base valence‐band discontinuity on Kirk effect in double‐heterojunction bipolar transistors

The effect of valence‐band discontinuity at the collector base heterojunction on the current gain and base charge storage is modeled. It is shown that the onset of the Kirk effect is accompanied by a sharp drop in the current gain and ft due to the formation of a potential barrier. The variation of barrier height with collector current density is determined and its effect on current gain and base transit time described. The results discussed here are applicable to Si/SiGe double‐heterojunction bipolar transistors.
Soil water storage dynamics in peatlands with shallow water tables.

Time domain reflectometry (TDR) was used to estimate soil water storage dynamics in several uncultivated blanket bogs and poor fens in southeastern Newfoundland during the summer growing season. The purpose of the research was to evaluate links between surface moisture conditions, evapotranspiration, and recharge processes in order to elucidate factors that govern blanket peat formation in the region. Water storage changes in the peat/Sphagnum above the water table (ΔSWS) were found to be important storage terms in daily water balance estimates. Daily mean ΔSWS values for bog and fen approximated −0.3 and −0.45 mm, respectively. It was also found that, i) fairly high peat water-holding capacities, ii) frequent atmospheric recharge, iii) atmospheric controls on evapotranspiration, and, iv) the transport of water into the unsaturated zone from the shallow water table via capillary and external wicking processes helped to preclude significant de-watering over the bulk of the peatland surfaces. Recharge via g.
Permafrost and Thermokarst Lake Dynamics in the Old Crow Flats, Northern Yukon, Canada

Aspects of the thaw lake cycle were investigated in Old Crow Flats (OCF), a 5600 km2 peatland with thousands of thermokarst lakes in the continuous permafrost of northern Yukon. It is located in the traditional territory of the Vuntut Gwitch'n, who expressed concern that climatic change may be affecting the permafrost and lakes of OCF. Field data collected in 2008-2011 provided the first assessment of spatial variability in permafrost temperatures across the treeline ecotone in OCF. Lake-bottom temperatures were recorded near the shores of four thermokarst lakes and talik configuration was defined beneath the lakes by jet-drilling to determine conditions controlling permafrost degradation in the area. Analytical and thermal models were used to relate field observations to current theory. Surface and subsurface conditions were examined in three drained lake basins and four expanding lakes to investigate how shore recession, talik development, and sediment deposition during lake expansion control the topography in lake basins after drainage. Permafrost temperature at the depth of zero annual amplitude varied between -5.1oC and -2.6oC on the Flats. Within the forest-tundra transition, spatial variability in permafrost temperatures appeared to be controlled by the snow-holding capacity of vegetation and the configuration of land covers in the surrounding landscape, which controlled snow supply. Annual mean lake-bottom temperatures close to shorelines were unaffected by spatial variations in on-ice snow depth, but accumulation of freezing degree-days at the lake bottom varied sufficiently to affect rates of permafrost degradation beneath the lake. Where ice reached the lake bottom, talik development rates were controlled by the ratio of freezing degree days to thawing degree days and the thermal offset in the lake sediment. After lake drainage and permafrost aggradation, thermokarst lake basins in OCF commonly develop depressed margins and raised centres. An elevation difference of up to 2 m was recorded between the margins and centres of drained basins, but this elevation difference was not associated with increased ice-wedge density or increased segregated ice content. A conceptual model based on sediment deposition patterns during lake expansion was proposed to explain the topography of drained lake basins in OCF.
Absorption, Desorption, and Transport of Water in Polymer Electrolyte Membranes for Fuel Cells

The transport of water vapor through a nafion membrane includes absorption of water at one membrane/gas diffusion layer interface, water transport in the membrane, and desorption of water at another interface. based on the structure of the membrane, a model for the water transport through the membrane is presented. it was assumed that the mass-transfer coefficients for the absorption and desorption of water and the water diffusion coefficient were dependent on the volume fraction of water (f(v)) in the membrane. these parameters were determined from steady-state water transport flux through the membranes at different water activity gradients. the results show that the mass-transfer coefficient for the absorption of water (k(a) = 3.53 x 10(-5)fv m/s, 353 k) is much lower than that for the desorption of water (k(d) = 1.42 x 10(-4)fv m/s, 353 k). the parameters k(a) and k(d) describe the nonequilibrium water uptake of the membrane on operating conditions. using these obtained parameters, the simulation results agree well with experimental data under many different conditions, including thickness of the membrane, water vapor/liquid water, temperature, and flow rate. © 2005 the electrochemical society. [doi: 10.1149/ 1.1899263] all rights reserved.
Dielectric relaxation studies of ion motions in electrolyte-containing perfluorosulfonate ionomers. 4. Long-range ion transport

Discussion de la loi de puissance decrivant la perte dielectrique de membranes Nafion contenant des electrolytes aqueux obtenue par Mauritz a l'aide de la theorie du transport dispersif des porteurs de charge dans les materiaux amorphes et de la theorie du phenomene de dispersion dielectrique anormal a basse frequence. Les resultats montrent que l'indice de puissance n pourrait etre utilise comme indice qualitatif de la regularite morphologique ou un indice quantitatif de la tortuosite du reseau conducteur
The Sunphotometer Airborne Validation Experiment 2012: Preliminary Results

(1) University of La Laguna, San Cristóbal de La Laguna, Spain, (2) Universitat de Valencia, Burjassot, Spain, (3) Met Office, United Kingdom, (4) University of Reading, Reading, United Kingdom, (5) Instituto di Scienze dell’Atmosfera e del Clima, Rome Tor Vergata, Italy, (6) Universitat de Barcelona, Spain, (7) Universidad de Valladolid, Spain, (8) Agencia Estatal de Meteorología (AEMET), Spain, (9) University of Oxford, United Kingdom
Solid solutions in the system Ag_2S–Ag_2Se

Optical, electron microprobe, and x-ray diffraction analysis of 88 samples of various compositions between Ag_2S and Ag_2Se synthesized at high temperature in sealed quartz tubing indicates the presence of two solid-solution series in this system at ambient (room) conditions. One series extends from Ag_2S to approximately Ag_2S_0. 4Se_0. 7 and has the Ag_2S-III-type structure (monoclinic). The second series ranges from Ag_2S_0. 3Se_0. 7 to Ag_2Se and is characterized by the Ag_2Se-II-type structure (orthorhombic). Members of both series, in appropriate proportions, characterize the apparent compositional gap between the two solid solutions. Gradual shifts in the locations of the x-ray diffraction peaks along the compositional gradient of each solid solution revealed an expansion of the d -spacing as the larger Se ion was substituted for S in the Ag_2S-III-type structure and a contraction as S was substituted for Se in the Ag_2Se-II-type structure. The reported discrete phase, Ag_4SSe (aguilarite, orthorhombic), appears to be simply a member of the monoclinic Ag_2S-III-type solid solution.
Fractal geometry of a numerically simulated flame surface

Two-dimensional, direct numerical simulations of premixed turbulent combustion in the so-called flamelet regime were done in an earlier study. The flame surfaces passed through stationary isotropic turbulence that was maintained by forcing at either large scales (LS) or small scales (SS) producing inertial ranges with power-law exponents of -3 and -5/3, respectively. In the present study, the impact of the inertial range scaling on the fractal dimension of the flame surface is considered. It is shown that the SS simulations, having the more classical -5/3 inertial range, yield fractal dimensions that are in closer agreement with experimental measurements in the literature than the LS simulations with the -3 inertial range. Indeed, the latter produce consistently lower fractal dimensions than the SS simulations and experiment. A theoretical expression for the fractal dimension of an isocontour of a passive scalar developed by Vascillicos and Hunt does not compare favorably with the simulation results for the flame surface. We propose an alternative empirical expression (D K = d - 0.42 - 0.lsq, where d is the dimension of the system and q is the inertial range exponent) that agrees more closely with the simulation results, particularly at high turbulence intensities.
ANALISIS PENGARUH KUALITAS LAYANAN TERHADAP TINGKAT KEPUASAN NASABAH TABUNGAN SIMPEDES PADA PT BANK RAKYAT INDONESIA (PERSERO), TBK KANTOR CABANG PATTIMURA SEMARANG

<p><em>The purpose of research is to analyze the service quality influence to the customer satisfaction of Simpedes savings product in Bank Rakyat Indonesia ltd Pattimura Branches Semarang. </em><em>This research is quantitative</em><em> </em><em>causal applied research. </em><em> </em><em>The population in this research is Simpedes savings </em><em>product</em><em> </em><em>in</em><em> </em><em>in Bank Rakyat Indonesia ltd Pattimura Branches Semarang </em><em>as many as 100 </em><em>customers. Data collection method used the purposive sampling. The data used in the research are primary and secondary data. The analytical model used in this research is </em><em>Multiple Linear Regression. Based on the results of research, service quality </em><em>has </em><em>significantly influence </em><em>on </em><em>the customer satisfaction</em><em>. Emphaty has the greatest influence customer satisfaction with beta of 31,1 and the lowest influence customer satisfaction is reliability with beta of 11,8. </em></p>
Application of thermodynamic model to study the ferroelectric properties of nAL and nHL homologous series

Using a thermodynamic model developed by us in an earlier paper [A. Singh and S. Singh, Thermodynamic model for the description of smectic C* and smectic A–smectic C* phase transition properties, Phase Trans. 83 (2010), pp. 205–222] for the description of SmC* and SmA–SmC* phase transition properties, we study, in detail, the temperature variation of spontaneous polarization P 0, tilt angle θ0 and helical pitch p of two homologous series nAL(n = 9, 10, 12) and nHL(n = 9, 10, 12, 14, 16) of ferroelectric mesogens. In this model, the free-energy density of a system is expanded in terms of three degrees of freedom – tensor orientational order , scalar smectic order ψ and polarization vector P and their coupling terms. The tilt vector ξ is not considered as an independent order parameter on the plea that governs ξ . The coupled equations for these order parameters are obtained, as usual, by the minimization of the free-energy density with respect to respective order parameters together with the criterion for the thermodynamic stability. Adopting usual method, we evaluate the relative contribution of each individual term of the expansion series and the values of P 0, θ0, and p as a function of temperature for the above-mentioned eight ferroic mesogens. We found that the theoretical results agree very well with the experimental data of all the mesogens.
A Set of Analytical Benchmarks to Test Numerical Models of Flow and Transport in Soils

Accurate model predictions of water flow and solute transport in unsaturated soils require a correct representation of relevant mechanisms in a mathematical model, as well as correct solutions of the mathematical equations. Because of the complexity of boundary conditions and the nonlinearity of the processes considered, general solutions of the mathematical equations rely on numerical approximations. We evaluate a number of numerical models (WAVE, HYDRUS_1D, SWAP, MARTHE, and MACRO) that use different numerical methods to solve the flow and transport equations. Our purpose is to give an overview of analytical solutions that can be found for simple initial and boundary conditions and to define benchmark scenarios to check the accuracy of numerical solutions. Included are analytical solutions for coupled transport equations that describe flow and transport in dual‐velocity media. The relevance of deviations observed in the analytical benchmarks for more realistic boundary conditions is illustrated using an intercode comparison for natural boundary conditions. For the water flow scenarios, the largest deviations between numerical models and analytical solutions were observed for the case of soil limited evaporation. The intercode differences could be attributed to the implementation of the evaporation boundary condition: the spatial discretization and the internode averaging of the hydraulic conductivity in the surface grid layer. For solute transport, accurate modeling of solute dispersion poses the most problems. Nonlinear and nonequilibrium sorption and coupled transport in pore domains with different advection velocities are in general accurately simulated.