Miracle-dz/UniFAR-FTUs huggingface dataset:
Ignition and extinction of flames near surfaces: Combustion of CH4 in air

Ignition and extinction characteristics of homogeneous combustion of methane in air near inert surfaces are studied by numerical bifurcation theory for premixed methane/air gases impinging on planar surfaces with detailed chemistry involving 46 reversible reactions and 16 species. One-parameter bifurcation diagrams as functions of surface temperature and two-parameter bifurcation diagrams as functions of equivalence ratio and strain rate are constructed for both isothermal and adiabatic walls. Lean and rich composition limits for ignition and extinction, and energy production are determined from two parameter bifurcation diagrams. For a strain rate of 500 s[sup [minus]1], CH[sub 4]/air mixtures exhibit hysteresis from [approximately] 0.5% up to [approximately] 12.5% and from [approximately] 5.5% up to [approximately] 13.5% near isothermal surfaces and adiabatic walls, respectively. Ignition temperature rises with composition from 1,700 to 1,950 K, without a maximum around the stoichiometric ratio. Under some conditions multiple ignitions and extinctions can occur with up to five multiple solutions, and wall quenching, kinetic limitations, and transport can strongly affect flame stability. Flames near the stoichiometric ratio cannot be extinguished by room temperature surfaces for sufficiently low strain rates. The role of intermediates in enhancing or retarding ignition and extinction is studied, and implications of the effect ofmore » catalytic surfaces on homogeneous ignition and extinction are discussed. Removal of H atoms and CH[sub 3] radicals by wall adsorption can increase extinction and ignition temperature of 6% CH[sub 4] in air by up to 300 K for a strain rate of 500 s[sup [minus]1]. « less
Highly efficient dye‐sensitized solar cells using phenothiazine derivative organic dyes

Two novel organic dyes have been synthesized using electron rich phenothiazine as electron donors and oligothiophene vinylene as conjugation spacers. The two dyes (2E)‐2‐cyano‐3‐(5‐(5‐((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐7‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)acrylic acid (PTZ‐1) and (2E)‐3‐(5‐(5‐(4,5‐bis((E)‐2‐(10‐(2‐ethylhexyl)‐10H‐phenothiazin‐3‐yl)vinyl)thiophen‐2‐yl)thiophen‐2‐yl)thiophen‐2‐yl)‐2‐cyanoacrylic acid (PTZ‐2) were fully characterized and employed in dye‐sensitized solar cells (DSCs) to explore the effect of disubstituted donors on photovoltaic (PV) performance. The solar cells sensitized by the PTZ1 dye have a high IPCE plateau of 80% and achieve a short‐circuit photocurrent density of 12.98 mA/cm2, an open‐circuit voltage of 0.713 V, and a fill factor (ff) of 66.6%, corresponding to a conversion efficiency of 6.17% under AM 1.5 100 mW/cm2 illumination. The different performance of the solar cells based on the two dyes can be understood from the studies of the electron kinetics by electrochemical impedance spectroscopy (EIS). These investigations reveal that disubstituted donors in the organic sensitizers of three or more conjugation units deteriorate the PV performance due to enhanced recombination. Copyright © 2010 John Wiley & Sons, Ltd.
SPECIATION OF Cr(III) AND Cr(VI) IN TANNERY WASTEWATER AND SEDIMENT SAMPLES ON AMBERSORB 563 RESIN*

ABSTRACT A simple method has been established for speciation of chromium(III) and chromium(VI) in natural water samples. The method is based on the solid phase extraction of the Cr(VI)–APDC chelate on the Ambersorb 563 carbonaceous resin filled mini-column. After oxidation of Cr(III) to Cr(VI) by using H2O2, the method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) concentrations. The influences of the various analytical parameters including pH, amounts of reagents, sample volume on the quantitative speciation values of chromium were investigated. Recoveries of more than 95% were found. No interferences due to major components of the natural water samples and some metal ions were observed. The detection limit based on the 3σ criterion was 2.70 µg/L for Cr(VI). The presented method was applied for the speciation of the chromium in the tannery wastewater samples from Bor Organized Industrial Region- Nigde (Turkey) with satisfactory results (recoveries >95%, RSD's<9%). *This study is a part of the Ph.D. thesis of Ibrahim Narin.
Polyisoprene-Polystyrene Diblock Copolymer Phase Diagram near the Order-Disorder Transition

The phase behavior of ten polyisoprene-polystyrene (PI-PS) diblock copolymers, spanning the composition range from 0.24 to 0.82 polyisoprene volume fraction (f PI ), has been studied near the order-disorder transition (ODT). Dynamic mechanical spectroscopy, transmission electron microscopy, and neutron and X-ray scattering have been used to characterize phase transition temperatures and ordered state symmetries. Five distinct microstructures were observed for this chemical system : spheres, hexagonally packed cylinders (HEX), lamellae (LAM), hexagonally perforated layers (HPL), and a bicontinuous cubic phase having an Ia3d space group symmetry. The bicontinuous Ia3d phase only occurs in the vicinity of the ODT between the HEX and LAM states at compositions of 0.65 ≤ f pI ≤ 0.68 and 0.36 ≤ f pI ≤ 0.39 (prior report). Farther from the ODT, within these composition ranges, the HPL phase occurs. We did not find the ordered bicontinuous double diamond (OBDD) morphology at any composition or temperature studied, and the overall phase diagram is qualitatively different from those reported previously for PI-PS block copolymers.
Extraction and characterization of chitin; a functional biopolymer obtained from scales of common carp fish (Cyprinus carpio l.): A lesser known source

Chitin is the most abundant natural amino polysaccharide and is estimated to be produced annually almost as much as cellulose. It has become of great interest not only as an industrialized resource, but also as a new functional material of high potential in various fields. Chitin was successfully extracted from the scales of a common Carp fish and characterized for it functional properties. Structural data of the chitin was determined by FT-IR and the crystalline and surface morphology were also studied by Powder X-Ray diffractometry and scanning electron microscopy (SEM). The proximate analysis determined was 2.12% moisture content, 1.56% ash and 4.18% Nitrogen. The amount of Ca, Mg, Zn, Fe, Cu and Mn present in the chitin was 26.84, 50.49, 21.80, 12.68, 0.22 and 1.17 mg/kg, obtained by atomic absorption spectrometry, respectively. Key word: Chitin, chitosan, biodegradable, biocompatibility, non-toxic, X-ray diffractormeter, scanning electron microscope (SEM), fourier transform infrared (FTIR).
Initial results from long‐term field studies at three sites on the effects of heavy metal‐amended liquid sludges on soil microbial activity

In a long‐term study of the effects on soil fertility and microbial activity of heavy metals contained in sewage sludges, metal‐amended liquid sludges each with elevated Zn, Cu or Cd concentrations were applied over a 3‐year period (1995–1997) to three sites in England. The experiments were sited adjacent to experimental plots receiving metal‐rich sludge cakes enabling comparisons to be made between the effects of heavy metal additions in metal‐amended liquid sludges and sludge cakes. The liquid sludge additions were regarded as ‘worst case’ treatments in terms of likely metal availability, akin to a long‐term situation following sewage sludge additions where organic matter levels had declined and stabilised. The aim was to establish individual Zn (50–425 mg kg−1), Cu (15–195 mg kg−1) and Cd (0.3–4.0 mg kg−1) metal dose–response treatments at each site, but with significantly smaller levels of organic matter addition than the corresponding sludge cake experiments. There were no differences (P > 0.05) in soil respiration rates, biomass carbon concentrations or most probable numbers of clover Rhizobium between the treatments at any of the sites at the end of the liquid sludge application programme. Soil heavy metal extractability differed between the metal‐amended liquid sludge and metal‐rich sludge cake treatments; Zn and Cd extractabilities were higher from the liquid sludge additions, whereas Cu extractability was higher from the sludge cake application. These differences in metal extractability in the treated soil samples reflected the contrasting NH4NO3 extractable metal contents of the metal‐amended liquid sludges and sludge cakes that were originally applied.
Influence of pulse chemical treatments on water relation in cut gerbera (Gerbera jamesonii cv.Pags) flowers.

The effect of 24 h pulse chemical treatments on the vase life and quality of cut gerbera (Gerbera jamesonii cv. Pags) flowers was studied in a completed randomized experiment. Cut flowers were kept in vases containing solutions of 8-hydroxyquinoline sulfate (8-HQS), aluminium sulfate, citric acid, calcium chloride, silver nitrate and distilled water (control). Thirty mg l -1 of sucrose was used for all treatments. Vase life was significantly (P<0.05) extended from 12.0 days (control) to 24.5 days by using combination of aluminium sulfate at 300 ppm and sucrose. Fresh weight (FW) and relative water content (RWC) data indicated that chemical treatments acted primarily by improving water uptake and consequently extending vase life, which suggests that the vase life, scape bending and wilting are all related to the water status of flower. The curvature of the stem in the end of vase life was associated with the folding and wilting of the stem in the vase.
Influence of pore fluid chemistry on the complex conductivity and induced polarization responses of Berea sandstone

The spectral induced-polarization (IP) response of rocks and soils is a complex function of pore solution chemistry, sample microgeometry, and surface chemical properties. We measure the complex conductivity and the time domain IP responses of Berea sandstone as a function of pore fluid ionic strength and pH. Complex conductivity is measured over the frequency range 10−3 to 106 Hz, and chargeability is computed using a time window of 0.16 to 1.74 s. The field IP parameters: phase, percent frequency effect, and chargeability are functions of both the surface and bulk electrical properties of the sample and are observed to decrease with increasing solution conductivity. Dividing these parameters by the sample resistivity yields normalized IP parameters (quadrature conductivity, metal factor, normalized chargeability) that are proportional to the imaginary component of the complex surface conductivity. Normalized IP parameters increase with ionic strength up to concentrations of 10−1 M NaCl and show a reduced response at pH 3, the point of zero charge for quartz-dominated systems. For concentrations >10−1 M NaCl, the normalized parameters decrease with increasing concentration. This decrease in surface polarization may indicate a decrease in the effective mobility of polarizing charges at high solution concentration. Our data indicate that normalized IP parameters are directly related to the physiochemical parameters that control the surface conductivity responses of rocks and soils. Normalization of IP measurements in environmental investigations should increase the effectiveness of IP surveys, especially in high-conductivity environments.
Grape-like mesostructured silica nanoparticle-decorated single-walled carbon nanotubes: Silica growth and dye adsorptivity

Single-walled carbon nanotube (SWCNT)-mesostructured silica nanoparticle (MSN) adsorbents (S-MSNs) were prepared through a simple one-step method with various loadings of SWCNTs. Their surface properties were characterized by XRD, TEM, N2 physisorption, and FTIR spectroscopy. A grape-like S-MSN was produced, for which the growth of MSNs became intense with increasing CNT loading. A bimodal pore structure also developed, which increased the average pore size and pore volume, but decreased the surface area. The increasing amount of CNTs was found to provide more sites for silica growth that enhanced the adsorptivity of the S-MSNs toward methylene blue (MB) dye. Accordingly, 0.1 g L−1 5 wt% S-MSN was able to adsorb 478 mg g−1 (qm) of 50 mg L−1 MB at pH 7 and 323 K. The equilibrium data were evaluated using the Langmuir, Freundlich, Redlich–Peterson, and Dubinin–Radushkevich isotherm models, with the Langmuir and Redlich–Peterson models affording the best fit to the adsorption data. The adsorption was best described by a pseudo-second-order kinetics model and thermodynamically favored the endothermic chemisorption process. These results indicated the potential of S-MSN as an effective new adsorbent for dye adsorption.
The reaction of ammonia with nitrogen dioxide in a flow reactor: Implications for the NH2 + NO2 reaction

The NH3/NO2 system has been investigated experimentally in an isothermal flow reactor in the temperature range 850–1350 K. The experimental data were interpreted in terms of a detailed reaction mechanism. The flow reactor results, supported by a theoretical analysis of the NH2NO2 complex, suggest that the NH2 + NO2 reaction has two major product channels, both proceeding without activation barriers: Our findings indicate that the N2O + H2O channel is dominant at low temperatures while H2NO + NO dominates at high temperatures. The rate constant for reaction (R21) is estimated to be 3.5 · 1012 cm3/mol-s in the temperature range studied with an uncertainty of a factor of 3. © 1995 John Wiley & Sons, Inc.
Strong Near‐Infrared Photoluminescence Emission of (003)‐Oriented MgTiO3 Thin Films

In this study, ilmenite-MgTiO3 films were sputtered on p-type Si(111) substrates and the extrinsic effects, such as grain size, crystallinity, and orientation of photoluminescence (PL) properties of the films are discussed. To reduce the effect of oxygen vacancies (act as shallow defects) on PL emissions in the films, oxygen (O2) was introduced as the sputtering gas and the excitation light source (λ = 532 nm) which has a corresponding energy (hν = 2.33 eV) below the shallow defect states was used. In this study, intense near-infrared (NIR) PL emission centered at 810.1 nm at room temperature can be observed when the MgTiO3 thin films exhibit the preferred (003)-orientation and accompanied by the presence of hexagon-shaped grains. In this study, the experiment results reveal that the NIR emission intensity of MgTiO3 films highly depend on crystal orientation and/or grain morphology.
Particle size distribution from small-angle X-ray scattering data

An improved transform technique has been developed [Gerber (1983). Thesis, Wilhelm-Pieck-University Rostock, German Democratic Republic] for calculating the particle size distribution N(R) for spherical particles with radii R from small-angle X-ray scattering data. This method permits N(R) to be calculated from analytical expressions that were derived for point collimation and for infinitely long slit collimation. A special procedure has been introduced in order to reduce termination errors. The technique described and those developed by Schmidt [Brill, Weil & Schmidt (1968). J. Colloid Interface Sci. 27, 479–492], Vonk [J. Appl. Cryst. (1976), 9, 433–440] and Glatter [J. Appl. Cryst. (1980), 13, 7–11] were used for calculating particle size distributions from theoretical scattering curves and from an experimental scattering curve of suspended SiO2 particles (Ludox). The results obtained by the different techniques were compared, and reasonable results are given by all methods employed. The accuracy of the size distributions calculated by the improved method is somewhat higher than that obtained by Schmidt's transform technique. With Glatter's procedure, the deviations from the exact distributions are comparable to those from this improved transform technique, but the use of Glatter's program requires a large computer, whereas the new method has the advantage of being suitable for a small computer. Vonk's program also requires a large computer, and the deviations obtained are larger than those produced by other methods. The experimental scattering curve of the Ludox sample was also evaluated by assuming a log-normal distribution for the particles. The parameters μ and σ of this function were determined from a set of small-angle X-ray scattering structural parameters. The resulting log-normal distribution is significantly different from the size distribution calculated by our method.
The essential oils of three unusual eucalypts: Eucalyptus curtisii, E. rubiginosa and E. tenuipes (Myrtaceae)

Eucalyptus curtisii Blakely & C. T. White, E. rubiginosa Brooker and E. tenuipes (Maiden & Blakely) Blakely & C. T. White all yielded essential oils which contained β-pinene, α-pinene, (E)-β-ocimene, α-terpineol and globulol as essential oil components. 1,8-cineole was present, but only at levels of less than 5%. © 1998 John Wiley & Sons, Ltd.
Effect of sugar factory distillery spent wash (DSW) on the growth pattern of sugarcane (Saccharum officinarum) crop.

Distillery spent wash is a rich source of organic matter and nutrients like nitrogen, phosphorus, potassium, calcium and sulfur. In addition, it contains sufficient amount of micro-nutrients such as iron, zinc, copper, manganese, boron, and molybdenum. A field experiment was conducted with different dilutions of distillery spent wash using sugar cane ( Saccharum officinarum ) variety Co1274 as test crop. The experiment was formulated with four treatments (25%, 50%, 75% and 100%) with three replicates, with a set of control for comparison. The growth parameters like height of the plant, length of the leaves, breadth of the leaves, girth of the stem, leaf area index, number of leaves per plant, no. of tillers per plant etc of the plant enhanced with increase in concentration of distillery spent wash up-to 75%. But in 100% concentration of distillery spent wash all the growth parameters showing a declining trend from the control. This increase in the parameters is statistically significant.
A mechanistic model for penicillin production

A mechanistic model for the production of penicillin has been investigated. Contois kinetics of growth coupled with a substrate-inhibition model for product formation has been used to predict data for batch-fed fermentation on synthetic and corn steep liquor medium. With the incorporation of oxygen limitation on growth and product formation it has been possible to investigate the effects of feeding rate, initial sugar concentration and the volumetric mass transfer coefficient for oxygen (KLa). Various experimentally observed trends for penicillin fermentation have been predicted qualitatively. Different product formation models have been critically reviewed with respect to the production of secondary metabolites.
Responses of Nurses and Other Healthcare Workers to Sexual Harassment in the Workplace

Sexual harassment against healthcare workers is an international problem, but little is known about how recipients of sexual harassment respond to this type of workplace violence. An integrative review was conducted that summarized the findings of 15 studies from around the world that revealed how healthcare workers respond to sexual harassment. The review indicated that recipients of sexual harassment experience a wide variety of aversive feelings, including fear, anger, and shock. Some also experience negative psychological and physical harms and negative employment-related consequences. In conclusion, more studies using increasingly sophisticated designs are required to develop an explanatory model that explicates complex relationships among characteristics of the harassment, institutional responses, and responses of the recipients over time.
Midgap states in corrugated graphene: Ab initio calculations and effective field theory

We investigate the electronic properties of corrugated graphene and show how rippling-induced pseudo-magnetic fields alter graphene's low-energy electronic properties by combining first-principle calculations with an effective field theory. The formation of flat bands near the Fermi level corresponding to pseudo-Landau levels is studied as a function of the rippling parameters. Quenched and relaxed ripples turn out to be fundamentally different is this respect: it is demonstrated, both numerically and analytically, that annealing of quenched ripples can destroy the flat bands.
Aqueous film drainage at the quartz/water/air interface

The effect of salt (sodium chloride) concentration on the drainage of a thin aqueous film between a hydrophilic quartz surface and a fast approaching air bubble has been studied using scanning interferometry. An increase in salt concentration increases the rate of drainage at the boundary ring of the draining film but is accompanied by a decrease at the centre of the film. The changes are manifested at distances beyond which equilibrium surface forces are anticipated to operate. The enhanced drainage rate at the boundary ring may arise from effects similar to those which control the flow of aqueous solutions in fine capillaries. Equilibrium thin-film thicknesses can be reasonably well predicted using standard DLVO theory. Film drainage rates exhibit a linear inverse square behaviour, of the film thickness vs. time, but diverge from extant theory.
The effects of storage periods on some quality features of various-sized potato varieties.

In this study, the effects of storage periods on some quality features of various dimensioned potatoes types were examined (2.5-5.0 cm, 5.0-6.5 cm and greater than 6.5 cm). The effects of storage duration on all properties except for the dry matter content were statistically significant. It was observed that with the extension of storage period, weight gain of the tubers decreased, and the other properties were not stable. There was no statistical significance among the tuber sizes in terms of specific weight, dry matter, the ratio of starch and protein and chip productivity, but weight loss and fat absorption ratio of the chips. The best results were obtained from 5.0-6.5 cm dimensioned tubers of Agria species with regard to features examined during storage.
Electronic Trap States in Methanofullerenes

The trap states in three fullerene derivatives, namely PC61BM ([6,6]‐phenyl C61 butyric acid methyl ester), bisPC61BM (bis[6,6]‐phenyl C61 butyric acid methyl ester) and PC71BM ([6,6]‐phenyl C71 butyric acid methyl ester), are investigated by means of thermally stimulated current measurements (TSC). Thereby, the lower limit of the trap densities for all studied methanofullerenes is on the order of 1022 m−3, with the highest trap density in bisPC61BM and the lowest in PC61BM. Fractional TSC measurements on PC61BM reveal a broad trap distribution instead of discrete trap levels, with activation energies ranging from 15 meV to 270 meV and the maximum at about 75 meV. The activation energies of the most prominent traps in the other two fullerene derivatives are significantly higher, at 96 meV and 223 meV for PC71BM and 184 meV for bisPC61BM, respectively. The influence of these findings on the performance of organic solar cells is discussed.