Miracle-dz/UniFAR-FTUs huggingface dataset:
Spectre des fluctuations thermiques a la surface libre d'un cristal liquide nématique

Nous calculons le spectre des fluctuations thermiques de la coordonnee verticale des points de la surface libre d'un cristal liquide nematique place dans un champ magnetique, en utilisant le theoreme de fluctuation-dissipation. La fonction de reponse a une force de pression exterieure de caractere sinusoidal s'exercant a la surface est evaluee a partir des equations linearisees de l'hydrodynamique. Nous avons utilise la theorie hydrodynamique de Eriksen et Leslie dans laquelle interviennent 5 coefficients de viscosite. Cependant, pour le domaine de frequences et de vecteurs d'onde qui nous interesse, le tenseur des contraintes visqueuses a sa partie antisymetrique negligeable et s'exprime uniquement a l'aide de 3 coefficients qui representent les 3 viscosites cinetiques typiques d'un milieu incompressible uniaxe. Le spectre des fluctuations depend en outre de la tension superficielle que nous supposons isotrope. Nous indiquons explicitement la repartition spectrale, quelles que soient les conditions d'amortissement et pour plusieurs geometries correspondant a diverses orientations relatives de la direction des molecules vis-a-vis du vecteur d'onde q des fluctuations. Enfin, nous envisageons l'effet d'une orientation des molecules en volume contrariant l'orientation imposee par la surface libre. La presence pres de la surface d'une zone ou l'orientation des molecules est distordue a le meme effet qu'une viscosite de surface ηs lorsque son epaisseur est petite devant q-1 ; ηs peut s'evaluer pour chaque geometrie en fonction de l'epaisseur de la distorsion et des viscosites du liquide.
A complete basis set model chemistry. VI. Use of density functional geometries and frequencies

The recently introduced complete basis set, CBS-Q, model chemistry is modified to use B3LYP hybrid density functional geometries and frequencies, which give both improved reliability (maximum error for the G2 test set reduced from 3.9 to 2.8 kcal/mol) and increased accuracy (mean absolute error reduced from 0.98 to 0.87 kcal/mol), with little penalty in computational speed. The use of a common method for geometries and frequencies makes the modified model applicable to transition states for chemical reactions.
Photoreactive nanomatrix structure formed by graft‐copolymerization of 1,9‐nonandiol dimethacrylate onto natural rubber

Formation of photoreactive nanomatrix structure was investigated by graft copolymerization of an inclusion complex of 1,9-nonandiol dimethacrylate (NDMA) with β-cyclodextrin (β-CD) onto natural rubber particle using potassium persulfate (KPS), tert-butyl hydroperoxide/tetraethylenepentamine (TBHPO/TEPA), cumene hydroperoxide /tetraethylenepentamine (CHPO/TEPA), and benzoyl peroxide (BPO) as an initiator. The graft copolymer was characterized by 1H-NMR and FT-IR after coagulation. The conversion of NDMA and the amount of residual methacryloyl group was found to be 58.5 w/w% and 1.81 w/w%, respectively, under the suitable condition of the graft copolymerization. The morphology of the film specimen, prepared from the graft copolymer, was observed by transmission electron microscopy (TEM) after staining the film with OsO4. Natural rubber particle of about 1.0 μm in diameter was dispersed in poly(NDMA) matrix of about 10 nm in thickness.
A simple, inexpensive, rapid, sensitive and solventless technique for the analysis of accelerants in fire debris based on SPME†

The current method of choice for the extraction of flammable or combustible liquid resides from fire debris samples is passive headspace concentration using activated charcoal strips (ACS) for adsorption of the liquid residues followed by elution with carbon disulfide or other suitable solvent. Presently, we report a new technique based on headspace solid-phase microextraction which has been successfully applied to the identification of a wide range of accelerants commonly seen in arson analysis. The SPME technique developed is simple, inexpensive, rapid, and eliminates the use of the highly flammable and toxic solvent carbon disulfide. Results using this SPME method have been directly compared to results obtained via the ACS technique for light, medium, and heavy petroleum distillates as well as gasoline. All of the accelerants studied were accurately identified by the SPME method with equal or greater sensitivity compared to the ACS method.
Synthesis and pH Responsive Self-Assembly of New Double Hydrophilic Block Copolymers

The synthesis of a new class of double hydrophilic block copolymers, namely poly(p-hydroxystyrene-b-methacrylic acid) (PHOS−PMAA), by a combination of anionic polymerization high-vacuum techniques and postpolymerization acidic hydrolysis, is described. A series of PHOS−PMAA copolymers with different molecular weights and compositions have been synthesized, indicating the good control over the molecular characteristics of the final copolymers. The solution behavior of PHOS−PMAA is studied as a function of the solution pH. A number of characterization techniques, including potentiometric titrations, fluorescence and IR spectroscopy, dynamic and electrophoretic light scattering, and atomic force microscopy, are used in an effort to elucidate the structural changes of the block copolymers at different levels, under different pH environments. Experimental results prove the pH responsive self-assembling ability of PHOS−PMAA copolymers.
Comparing Photovoltaic Capacity Value Metrics: A Case Study for the City of Toronto

Hourly electric power demand data in Toronto from 2000 to 2006 was analyzed along with coincident, simulated hourly photovoltaic (PV) power generation to quantify PV capacity value on a year‐round basis. Three different methods commonly employed by electric utilities were used to assess PV capacity value, and their results were compared. The first method is the Garver approximation to effective load carrying capability (ELCC), which served as a benchmark for capacity value. The other two methods equate PV capacity value with the capacity factor during “peak demand intervals”: for method 2 the interval includes all hours with loads within a given per cent deviation from the peak load; for method 3, a fixed “on‐peak” interval of 11–17 h in June–August is used. Methods 2 and 3 yielded PV capacity values of about 40%, in agreement with the results of the Garver approximation at low grid penetration. This is considerably higher than the yearly PV capacity factor of about 12%, and is in good agreement with previous studies. Capacity value varies significantly from year to year: for instance, values from method 1 at low grid penetration levels range from 30% (year 2000) to 44% (year 2006). Yearly variations in capacity value appear correlated with variations in the demand summer to winter peak ratio, reflecting the fact that PV capacity value is strongly linked to its capacity to reduce peak demand (“peak shaving”) during the summer. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Gender Differences in Statistics Anxiety with Undergraduate College Students

This empirical study examined gender differences in statistics anxiety with 156 undergraduate college students (48 males, 107 females) from a liberal arts college in the United States. Students completed surveys regarding number of prior statistics classes completed and statistics anxiety. Three subscales of the Statistical Anxiety Rating Scale (STARS; Cruise, Cash, and Bolton, 1985) which measures statistics anxiety were used. No gender differences were obtained for the Worth of Statistics and Computation Self-Concept subscales. Females had greater anxiety on the Test and Class Anxiety subscale than males. For males, no significant correlations were obtained between statistics anxiety and course grades. For females, significant correlations were obtained between Worth of Statistics and course grades (r = .230, p < .05) and Computation Self-Concept and course grades (r = .226, p < .05).
Influences of Substrate and Annealing on the Structural and Optical Properties and Photoluminescence of Nanocrystalline ZnO Films Prepared by Plasma Assisted Pulsed Laser Deposition

Single-crystalline silicon, amorphous quartz, and single-crystalline sapphire were used as the substrates for the deposition of nanocrystalline zinc oxide (nc-ZnO) thin films by plasma assisted pulsed laser deposition from metallic zinc at low temperature below 80 °C, and a postdeposition annealing process was performed for the deposited nc-ZnO thin films. The influences of substrate and annealing on the structural and optical properties as well as the photoluminescence of the prepared nc-ZnO thin films were studied. Raman spectroscopy and Fourier-transform infrared spectroscopy measurements reveal the wurtzite ZnO phase in the films. X-ray diffraction results indicate the nanocrystalline structure of the films with c axis perpendicular to substrates. Optical characterization shows that the prepared films have an ultraviolet (UV) absorption edge near 380 nm with a direct band gap of about 3.25 eV. The prepared films emit predominantly UV photoluminescence at light excitation. The structure and properties .
ROLE OF PROTECTION PROVIDED BY EMBLICA OFFICINALIS LINN. AGAINST RADIATION AND LEAD INDUCED HISTOLOGICAL CHANGES IN THE JEJUNUM OF SWISS ALBINO MICE

Exposure to ionizing radiation increases the production of the reactive oxygen species (ROS) leading the irradiated cells into a state of oxidative stress. Furthermore, Lead exposure along with ionizing radiation can potentially become toxic to the tissues due to the heightened oxidative stress. In the present study adult male Swiss albino mice were procured and divided into seven groups. Group (II to IV) serving as control, received sub lethal dose (3.0 Gy or 6.0Gy) and /or lead acetate (20ppm) in drinking water ad libitum . The experimental groups (V to VII) were given aqueous solution of Emblica (1000 mg/ Kg b.wt./ animal/ day) orally seven days prior to radiation and/or lead acetate treatment. Sham- irradiated animals of Group I served as normal. Animals of all the groups were autopsied at each post treatment interval of 1, 2, 4, 7, 14 and 28 days. After the experiments observed number of lesions in the intestinal epithelium from outer coat to inner mucosa. Loosened sub mucosa with hyperaemia and hemorrhage, shortened crypts and a number of apoptotic cells with severe cytoplasmic variations were noted. Villi had a rough surface, wavy epithelium and hydropic degeneration up to day-2 and thereafter, a recovery from intestinal lesions was initiated and noticed till the last autopsy interval. After the combined exposure of gamma radiation and lead acetate, Group IV exhibited same pattern of damage but severe histopathological alteration than individual exposure of radiation or lead acetate indicating â€œsynergistic â€œeffect. Process of recovery started on day-14 after the combined treatment but the process was slow. The Combined treatment showed synergistic effect. In experimental groups less severe radiolesions and an early onset of recovery was observed. Therefore it may be deduced that Emblica is a good herbal radioprotector and may be useful for the clinical applications in human beings during radiotherapy. Â
Kinetic Studies of Phytosterol Adsorption on Zeolite

Abstract Equilibrium isotherms of sterol adsorption on zeolite show the characteristics of irreversible equilibrium adsorption. First order and second order surface adsorption control mechanisms as well as micropore diffusion control model failed to satisfactorily describe the kinetics of sterol adsorption on zeolite. From the analysis of adsorption data, it was found that macropore diffusion control model satisfactorily describes the kinetics of sterol adsorption on zeolite. The effect of temperature on the diffusivity during adsorption was found to conform to the Eyring equation. It was shown that a change in temperature has a negligible effect on the selectivity of sterol adsorption on zeolite.
NOx Formation in High-Pressure Jet-Stirred Reactors With Significance to Lean-Premixed Combustion Turbines

Measurements of NOx and CO in methane-fired, lean-premixed, high-pressure jet-stirred reactors (HP-JSRs) independently obtained by Rutar [1] and Rutar et al. [2] and by Bengtsson [3] and Bengtsson et al. [4] are well predicted assuming simple chemical reactor models and the GRI 3.0 chemical kinetic mechanism. The single-jet HP-JSR of Rutar [1] and Rutar et al. [2] is well modeled for NOx and CO assuming a single PSR for Damkohler number below 0.15. Under these conditions, the estimates of flame thickness indicate the flame zone, that is, the region of rapid oxidation and large concentrations of free radicals, fully fills the HP-JSR. For Damkohler number above 0.15, that is, for longer residence times, the NOx and CO are well modeled assuming two PSRs in series, representing a small flame zone followed by a large post-flame zone. The multi-jet reactor of Bengtsson [3] and Bengtsson et al. [4] is well modeled assuming a large PSR (over 88% of the reactor volume) followed by a short PFR, which accounts for the exit region of the HP-JSR and the short section of exhaust prior to the sampling point. The Damkohler number is estimated between 0.01 and 0.03. Our modeling shows the NOx formation pathway contributions. Although all pathways, including Zeldovich (under the influence of super-equilibrium O-atom), nitrous oxide, Fenimore prompt, and NNH, contribute to the total NOx predicted, of special note are the following findings: 1) NOx formed by the nitrous oxide pathway is significant throughout the conditions studied; and 2) NOx formed by the Fenimore prompt pathway is significant when the fuel-air equivalence ratio is greater than about 0.7 (as might occur in a piloted lean-premixed combustor) or when the residence time of the flame zone is very short. The latter effect is a consequence of the short lifetime of the CH radical in flames.Copyright © 2001 by ASME
Removal of methylene blue and acid orange 7 from aqueous solutions by activated carbon coated with zinc oxide (ZnO) nanoparticles: equilibrium, kinetic, and thermodynamic study

AbstractVarious industries like textile, plastic, pulp, and paper produce dye containing wastewaters that have harmful effects on the environment as well as human health. The aim of this study was to investigate the effect of granular activated carbon (AC) coated by zinc oxide nanoparticles (ZnO-np) in the removal of dyes, methylene blue (MB) and acid orange 7 (AO7), from aqueous solutions. The morphology of the AC and AC–ZnO was determined by SEM and the FTIR spectra confirmed the strong interaction between AC and ZnO. The effect of various parameters, such as nanoparticles loading onto the AC, pH, contact time, dye concentration, ion strength, temperature, and adsorbent regeneration, was studied on the adsorption. The results showed that the surface structure of the raw AC was porous and had irregular shapes, but the surface of the modified AC (AC–ZnO) due to the homogenous coating of the ZnO-np onto the AC was approximately uniform and regular. The sorption capacity and optimum contact time for the rem.
Effect of the temperature on the drawing behavior of poly(ether ether ketone)

This study examines the drawing behavior of amorphous films of poly(ether ether ketone) (PEEK) and the effect of the drawing and the drawing temperature on some physical properties of the drawn samples. The thermal analysis shows that the amorphous films drawn at 200% of deformation and at temperatures of 80, 120, and 140°C crystallize by heating and the crystallization occurs at lower temperature with a lower crystallization enthalpy. The first effect can be related to the influence of orientation on the crystallization rate and the second to strain-induced crystallization. The dynamic—mechanical behavior of the drawn samples is in good agreement with the thermal analysis and confirms the presence of strain-induced crystallization at drawing temperatures well below 180°C. © 1992 John Wiley & Sons, Inc.
Leisure activities and their presence in social networks in potentially vulnerable youth

La atencion a los colectivos en riesgo de exclusion social en referencia a la alfabeti­zacion digital ha de tener mayor protagonismo en la investigacion educativa y social. El objetivo del estudio es analizar la presencia y difusion en las redes sociales de las actividades de ocio de un colectivo de jovenes potencialmente vulnerable, relacionandolo con el sexo y las areas geograficas de residencia. La muestra ascendio a 140 estudiantes espanoles de Formacion Pro­fesional Basica. Se aplico un cuestionario estructurado en diferentes bloques tematicos, del que se seleccionaron los 3 items que indagaban en el tema objeto de estudio. Se llevaron a cabo analisis descriptivos e inferenciales. Los resultados manifiestan que un 62.8% difunden sus actividades de ocio en las redes sociales, siendo las actividades fisicas las experiencias mas compartidas por este colectivo. Los chicos publican en mayor medida actividades festivas. Son los nortenos y quienes residen en el centro de Espana los que mas comunican en las redes so­ciales las actividades fisicas y los levantinos quienes mas comparten las experiencias culturales. Las conclusiones de este estudio han proporcionado claves que optimizan la educacion del ocio digital de los estudiantes de Formacion Profesional Basica para un uso constructivo y critico de las redes sociales, lo que contribuira a la alfabetizacion digital de este colectivo y, por ende, a minimizar las posibilidades de pertenecer a escenarios de riesgo.
Precise Measurement of Chlorine Isotopes Based on Cs2Cl2 by Thermal Ionization Mass Spectrometry

Abstract An improved procedure for precise measurement of chlorine isotope ratios in geological samples based on Cs2Cl+ ion by thermal ionization mass spectrometry is reported. Using this procedure the 37Cl/35Cl ratio of NIST SRM 975 is determined to be 0.318929±0.000028(1[sgrave]) with a precision of 0.009%(1 [sgrave]). The procedure has been successfully applied to study the variation of chlorine isotopic compositions in seawater and to determine atomic weight of chlorine.
Effect of Hydrocolloids on the Pasting Profiles of Tapioca Starch Mixtures and the Baking Properties of Gluten‐Free Cheese Bread

The effect of guar gum and a guar gum/hydroxypropyl methylcellulose (HPMC) blend on the pasting profile of a tapioca starch–precooked corn flour mixture was assessed. Moreover, the baking quality characteristics of gluten-free (GF) cheese bread with these hydrocolloids added were evaluated. The properties were weight, height, diameter, specific volume, hardness, dough stickiness, and dough and crumb moisture content. The guar gum increased the peak, breakdown and final viscosities, whereas the guar gum/HPMC blend increased the setback viscosity. The addition of hydrocolloids (guar gum and guar gum/HPMC) decreased the GF dough stickiness. As the concentration of guar gum increased, the hardness of the GF cheese bread decreased. Adding guar gum at levels of 5% w/w based on the amount of cheese prevented increases in the hardness of the GF cheese bread during 6 days of storage and, therefore, might be used to increase the shelf life of this product. Practical Applications This research would have practical applications in gluten-free (GF) cheese bread in terms of providing technological information about the influence of hydrocolloids on the quality characteristics of this product. Gums and hydrocolloids are essential ingredients in GF bread formulations for improving the texture and the appearance of the final products. In this study, guar gum and a guar gum/hydroxypropyl methylcellulose blend were used to overcome quality losses and improve the texture properties of GF cheese breads. Adding guar gum at levels of 5% w/w based on the amount of cheese decreased hardness in the GF cheese bread during storage for 6 days at room temperature and, therefore, can assure a longer shelf life.
Rigorous modeling of UV absorption by TiO2 films in a photocatalytic reactor

The radiation absorption profiles on the surfaces of TiO 2 films in a corrugated-plate photocatalytic reactor were modeled based on first principles. A new term, the local-area-specific rate of energy absorption (LASREA), was adopted to describe the catalyst surface radiation in heterogeneous photoreactors. The LASREA and the energy absorption efficiency were both quite sensitive to the dimensions of the corrugated plates. Due to the multiple photon reflections between the opposing surfaces, corrugated plates possess a superior capability for recapturing longer wavelength photons that would otherwise be reflected out of some reactor designs. This results in higher energy absorption efficiency and more uniform LASREA on the catalyst films. Compared to a flat plate, corrugations are predicted to enhance the energy absorption efficiency by up to 50% for UV-A fluorescent-lamp-powered systems and more than 100% for solar-powered systems.
Preconcentration of some trace metal ions on coated alumina modified by 1-((6-(-(2-hydroxynaphthalen-1-yl)methyleneamino) hexylimino) methyl) naphthalen-2-ol

A sensitive and efficient method for preconcentration of trace amounts of some metal ions such as Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Cr3+, and Fe3+ ions based on modification of sodium-dodecyl-sulphate (SDS) coated alumina with 1-(6-(-(2-hydroxynaphthalen-1-yl) methyleneamino) hexylimino) methyl) naphthalen-2-ol (HNMAHN) is reported. The method is based on the uptake of these ions following their chelation with HNMAHN and their recovery using a suitable eluent. The influence of parameters such as pH, concentration of ligand and amount of coated alumina, SDS concentration, eluent (type and concentrations), and elution volume on metal ion recoveries are investigated. The preconcentration factor is 150 (10 mL elution volume) for a 1500 mL sample volume. The method has been successfully applied for extraction and determination of these ions content in some real samples. Extraction efficiency is generally >95% with low relative standard deviations between 1.8% and 2.4 %.
Measuring the Heat Increment of Activity in Growing-Finishing Swine

ABSTRACT AN indirect calorimeter was shown to be adequately described as a linear, first order, constant coefficient system. Dynamic variation in the heat production of animals, normally obscured when measured using indirect calorimeters, could, therefore, be recovered via deconvolution and methods are presented to do this. These methods were applied in the measurement of activity related heat production of 40 kg swine. When the deconvolution methods were applied to measured data, a close correlation was found between observed behavior and the resulting changes in heat production. Results showed that, on average, heat production rate was increased 95% above the resting level during standing activity
The Preparation and Characterization of Glycerol Pseudo-Thermoplastic Starch/Glycerol Pseudo-Thermoplastic Polyvinyl Alcohol (GTPS/GTPVA) Biodegradable Films Using the Solution Casting Method

Starch and polyvinyl alcohol (PVA) are non-plasticized biodegradable materials. The purpose of this research was to transform starch and PVA into pseudo-thermoplastic starch (GTPS) and pseudo-thermoplastic PVA (GTPVA). Plasticizer (Glycerol) was used to reduce the molecular chain interactions and the melting temperatures, and then blended them via solution casting to form GTPS/GTPVA biodegradable films. Experimental tests evaluate the effect of plasticizer on GTPS/GTPVA films; the results indicate that GTPS/GTPVA-50/50 biodegradable films had excellent plasticization effect. Therefore, the method presented here should be useful in preparing GTPS/GTPVA biodegradable films.