Miracle-dz/UniFAR-FTUs huggingface dataset:
Ferrochirality: a simple theoretical model of interacting, dynamically invertible, helical polymers, 2. Molecular field approach: supports and the details

Using a molecular field approach, the effect of interaction between reversibly invertible, helical polymers is investigated theoretically. The helices are modelled by nearest-neighbour statistical thermodynamics. If the interaction energy between two helices of common handedness is lower than that of oppositely handed ones, a critical temperature Tc exists, below which the system spontaneously must leave the racemic state, though there is no contact to any chiral centre or force. This is analogous to the second-order phase transition of ferromagnets. The critical point increases with molecular weight and optical persistence of the helices. At the critical point the system is highly sensitive to any chiral influence. Doping with 1 ppb of a chiral additive leads to a relative optical rotation of order 10−3 at the critical point. This corresponds to an intrinsic energy difference of left- to right-handed monomeric units of only 10−8 J/mol. The cooperative effects in chirally doped nematic poly(hexyl isocyanate) (PHIC) can be easily described without using the improbable assumption that the supramolecular cholesteric arrangement with an axis-to-axis rotation of only 0,001° must be the reason for the collective helix sense preference in this system. On the other hand, if the chain-to-chain interaction is transmitted through this supermolecular twist, the structure of the equations is altered slightly only and critical behaviour must be expected as well.
Effect of soil and foliar application of boron on wheat productivity in north east alluvial plain of eastern India

On-farm trials were conducted during rabi season of 2013 in a randomized block design with six treatments on boron deficits soil at farmer’s field by KVK Purnea (Bihar) to validate, refine and popularize the technology developed at Bihar Agricultural University Sabour, Bhagalpur (Bihar) for enhancing the productivity of wheat {Triticum aestivum (L.) emend. Fiori & Paol. }. Results revealed that all B application i.e. 1.0 & 2.0 Kg/ha B application as basal, 0.2% foliar application of B at 2-5% spike initiation, 1.0 & 2.0 Kg/ha B application as basal + 0.2% foliar application of B at 2-5% spike initiation were increased plant height, spikes/m2, spike length, grains/spike and 1,000-grain weight, grain yield, straw yield and nutrient uptake over farmer’s practice (No B). 2.0 Kg/ha B application as basal + 0.2% foliar application of B at 2-5% spike initiation produced 15.1% higher grain yield as compared to farmer’s practice (No boron). 2.0 Kg/ha B application as basal + 0.2% foliar application of B at 2-5 spike initiation was most economical. This boron application on wheat crop recorded ₹ 23.51 ×103 /ha net returns along with 1.20% benefit: cost ratio.
Simulation of temperature and electric field-dependent barrier traps effects in AlGaN/GaN HEMTs

We considered electron trapping and detrapping processes in the AlGaN barrier of AlGaN/GaN high electron mobility transistors as that trapping is the process of electrons directly tunneling from the gate metal into the AlGaN barrier traps while detrapping is electrons emission from the traps into the AlGaN conduction band by phonon-assisted tunneling. By fully coupling the electron emission characteristic time with the device thermal and electrical behavior, simulations were performed to comprehensively analyze the contributions of device bias, accounting for self-heating and electric field dependent electron detrapping. Discussions on the current-transient method for traps characterization based on these simulations and impact of traps-dependent reverse gate current on drain current collapse are presented.
On the low frequency noise mechanisms in GaN/AlGaN HFETs

The low frequency noise in GaN/AlGaN heterostructure field effect transistors (HFETs) was studied in the temperature range from 8 to 300 K. At gate biases close to the threshold, the noise came from the device region under the gate, and the Hooge parameter αch was inversely proportional to ns (α ~ 1/ns) in the entire temperature range. This dependence might be explained by electron tunnelling from the 2D gas into the traps in the adjoining GaN or AlGaN layers. At voltages close to zero, the ungated source-gate and gate-drain regions were responsible for the noise, and the Hooge constant was two orders of magnitude larger. This result is consistent with recent studies of the mechanism of the current collapse in GaN-based FETs. A notable contribution from the generation-recombination noise with activation energy 0.24 eV was observed in the temperature interval from 50 K to 150 K.
A Review on the Sintering and Microstructure Development of Transparent Spinel (MgAl2O4)

A review of the densification mechanisms and the microstructural development for transparent spinel made by free sintering and by hot pressing is given. The paper is divided into two main parts. The first part considers spinel without any sintering additives because there still is some controversy concerning the role of cation stoichiometry on sintering and grain growth. The second part discusses the role of the classic sintering aid, LiF, in processing transparent spinel. LiF is shown to have multiple behaviors: (1) it initially wets spinel and forms a liquid phase at relatively low temperatures, which affects early-stage densification and also grain growth; (2) upon cooling from intermediate temperatures, or even from higher temperatures if microstructure evolution (e.g., formation of closed porosity) prevents volatization, the LiF-containing liquid dewets and resides in isolated pockets; (3) LiF alters the cation stoichiometry, thereby enhancing diffusion via an increase in the concentration of oxygen vacancies; this affects both the densification rate and grain growth; and (4) it reacts with impurities in the system, thereby acting as a cleanser. For the production of transparent spinel, it is critical that LiF or associated reaction products not be retained as a secondary phase.
An Exploration of the Effects of Reversibility in Chain Transfer to Metal in Olefin Polymerization

A kinetic model was derived to investigate the effects of reversibility in chain transfer to metal in olefin polymerization. The model predicts both number- and weight-average molecular weights, Mn and Mw, as a function of several reactor input variables including the constants for chain transfer and reversible transfer. A number of interesting and nonobvious insights into molecular weight distributions are gained from these simulations. The most revealing result is the variation of the molecular weight distribution (Mw/Mn) with conversion. In the absence of reversible transfer, the Mw/Mn is always greater than or equal to 2. Regardless of the magnitude of the reversible transfer constant, Mw/Mn approaches 2 as Mn approaches its maximum value. More dramatic deviations from Mw/Mn = 2 are observed for higher chain transfer constants. Polymerization data from two bis(phenoxyimine)zirconium catalyst systems are presented to demonstrate these effects. These results indicate that singular polymerizations should.
Environmental fate and behavior of some PAHs at roadside ambient air in a fast developing city environment of northern India

Atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations were measured at two monitoring stations (interior and outskirt of the city) for a span of one year during 2013 at Jalandhar, a fast developing city in the state of Punjab in northern India. The objective of the study was to ascertain PAH contamination levels, distribution behavior, seasonal variation, and ratio of low and high carcinogenic PAHs in the ambient air. Samples were collected using high volume sampler fitted with glass fiber filter paper and polyurethane foam plug (PUF) erected at two monitoring stations of the city. The PAHs were extracted by soxhlet using toluene as a solvent and analyzed on gas chromatography-flame ionization detector. Recovery range was found between 30% and 70% with the lower value corresponding to the low molecular weight PAH compound.The mean concentration of total low/high carcinogenic PAHs (among 16 PAHs) for the year was found to be 4.79 and 5.49 ng/m3 (ratio 1:1.14) in the interiors and 3.55 and 5.79 n.
Ge/Si Heterojunction Photodiodes Fabricated by Low Temperature Wafer Bonding

Ge/Si heterojunctions are formed by wet wafer bonding at annealing temperatures of 250 or 350 °C. Photodiodes fabricated using Ge/Si heterojunctions exhibit photocurrents flowing over the heterojunction with an internal quantum efficiency higher than 80% at wavelengths between 1000 and 1550 nm. The measured photocurrent–voltage and capacitance–voltage characteristics reveal that the electrical property of the heterojunctions is the same as that for samples fabricated by higher temperature annealing.
Run‐off transport of herbicides during natural and simulated rainfall and its reduction by vegetated filter strips

The efficiency of filter strips in protecting watercourses against herbicides in run‐off was evaluated in field experiments in western Germany. Surface run‐off caused by natural rainfall and related transport of metolachlor, terbuthylazine and pendimethalin were measured on plots of 40 m length without filter strips (F0), and after passing over three types of herbicide‐untreated field margin: 12 m conservation headland (CH12), 6 m (GF6) and 12 m grass strips (GF12). Run‐off was also measured after simulated rainfall on 7 m long plots without (F0) and with 3 m grass strips (GF3). All three herbicides were transported both in dissolved and in adsorbed forms; the partitioning depended on their water solubility with metolachlor and terbuthylazine mainly translocated in dissolved form (F0: highest mean concentrations for a natural run‐off event 721 and 220 μg L−1, respectively). Pendimethalin was predominantly transported in adsorbed form (maximum mean concentration 11.2 μg L−1). In the sediment, the highest mean herbicide contents in a single natural event (F0) accounted for 2294 μg kg−1 (metolachlor), 1317 μg kg−1 (terbuthylazine) and 5648 μg kg−1 (pendimethalin). The proportions of applied herbicide translocated were 0.3% (metolachlor), 0.2% (terbuthylazine) and 0.06% (pendimethalin; F0, natural rainfall). The extent of herbicide transport decreased with time but within this trend soil sealing, soil moisture and amount and intensity of rainfall increased losses. Compared with the F0 plots, the reduction of herbicide translocation after natural rainfall reached 80–83% (CH12), 80–88% (GF6) and >99% (GF12) over the 3‐year period. The 12 m grass strips allowed only one extreme run‐off event to pass through, thus providing a highly effective watercourse protection against herbicide pollution.
Energy dependence of deep level introduction in electron irradiated GaAs

The energy dependence of the introduction rates of the E2–E5 traps which are created by electron irradiation at room temperature has been studied and found to correspond to a threshold energy for production of 10 eV. A comparison is given between these results and other published results dealing with defects introduced by irradiation at 77 K.
Fungicide and Temperature Affect Leachate-Predicted Germination of Cotton1

The ASA-610 Automatic Seed Analyzer is used to predict the germination of acid delinted cotton (Gossypium hirsutum L.) seeds, reportedly in 24 h as compared to 7 days by standard methods. The prediction is based on the electrical conductivity of seed leachate, with higher leachate resulting in higher conductivity values and indicating lower germination potential. Because cotton planting seeds usually are treated with fungicides and instruments such as the ASA-610 may be used to assess planting seed quality without using controlled environmental chambers, this research was initiated. We studied the effects of fungicide treatments and temperature during soaking on ASA-610-predicted germination of cotton seeds. Corre lations among ASA-610-predicted germination and standard (30°C) and cool (18°C) germination tests were determined. Fungicide effects were evaluated by use of aliquots from a single seed lot of ‘Stoneville 213’ treated with 17 different fungicides and/or formulations plus an untreated control and a nine-entry fungicide test, again applied to aliquots of a single seed lot of Stoneville 213. Samples from 17 commercial planting seed lots were used to study the effects of soaking temperatures and to investigate the correlation between the ASA-610-predicted germination and standard germination at 30°C. Of 25 fungicide treatments studied, 20 did not significantly affect ASA-610-predicted germination when seeds were soaked for 19 h and partitioned at 55µA/seed. Soaking cotton seeds for 19 h at 18°C resulted in Significantly higher ASA-610-predicted germination than soaking at 24 or 30°C. Correlation analysis indicated that the ASA-610 will not predict accurately the germination of aciddelinted, commercial planting seeds as defined by standard germination procedures.
Interfacial tensions near critical endpoints: experimental checks of EdGF theory

Predictions of the extended de Gennes–Fisher local-functional theory for the universal scaling functions of interfacial tensions near critical endpoints are compared with experimental data. Various observations of the binary mixture isobutyric acid + water are correlated to facilitate an analysis of the experiments of Nagarajan, Webb and Widom who observed the vapour–liquid interfacial tension as a function of both temperature and density. Antonow's rule is confirmed and, with the aid of previously studied universal amplitude ratios, the crucial analytic ‘background’ contribution to the surface tension near the endpoint is estimated. The residual singular behaviour thus uncovered is consistent with the theoretical scaling predictions and confirms the expected lack of symmetry in (T−Tc ). A searching test of theory, however, demands more precise and extensive experiments; furthermore, the analysis highlights a previously noted but surprising, threefold discrepancy in the magnitude of the surface tension of isobutyric acid + water relative to other systems.
DTPA AND MEHLICH-3 MICRONUTRIENT EXTRACTABILITY IN NATURAL SOILS

Most soils of the humid area in the Iberian Peninsula are characterized by acid, desaturated, organic rich surface horizons. In this study micronutrients (Cu, Fe, Mn and Zn) were extracted using DTPA and Mehlich-3. Total contents were also determined by digestion with nitric acid. Seven natural soil profiles, representing major acid soil types developed over a wide variety of parent materials were collected. In addition, three soil profiles containing carbonates and/or a high base saturation were sampled. The organic matter content when all samples were included in the data set ranged between 0.37 and 26.51%. For the acid set of samples, Mehlich-3 extractable concentrations of Cu, Fe, Mn and Zn were higher than contents extracted by DTPA. However, DTPA extracted higher concentrations of Cu, Fe and Mn than Mehlich-3 in near neutral or calcareous soils. Correlation coefficients between DTPA and Mehlich-3 extractable amounts were in the range from 0.49 to 0.96 for the set of acid soil samples and in the range from 0.71 to 0.92 for non-acid horizons. However, for acid and non-acid samples combined, correlations between micronutrient contents extracted by both solutions were much weaker and not significant. Results illustrate difficulties for selecting a single multielement extractant for different soils of the studied region. Interactions between micronutrient extractability, pH and organic matter content were evaluated. In all of the studied soil profiles, there was a decrease in the extractable Cu, Fe, Mn and Zn contents with increasing soil depth.
Synthesis and characterisation of monodisperse zirconia particles

Monodisperse spherical ZrO2 particles were prepared by controlled hydrolysis of zirconium tetraalkoxide in alcoholic solution. Ageing the reaction solution at 60 °C for 4 h yields particles with sizes in the range between 200 and 2000 nm. The influence of various ions and surfactants on the final product was investigated. Stable suspensions of coated, monodisperse, zirconia particles were prepared by hydrolysis and subsequent polymerisation of tetraethoxysilane in an alkaline ethanol solution. Thermal analysis revealed that the weight loss of bound water occurred below 400 °C and is about 35 %. The phase transition from amorphous zirconia to the tetragonal phase proceeded at approximately 450 °C, the transition to the monoclinic phase began at about 600 °C and was completed at about 800 °C. The crystallinity of the powders was investigated by X-ray diffraction. Electrophoretic measurements were carried out to determine the charges on the particle surface. Elementary analyses were used for further investigations. On the basis of the results obtained, the mechanism of particle formation was discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cheesemaking with vegetable coagulants—the use of Cynara L. for the production of ovine milk cheeses

This paper reviews the use of plant extracts as vegetable coagulants for cheesemaking. It covers the plants used as sources of coagulants, with a historical overview and particular emphasis on Cynara species. The genus Cynara L. , its composition, milk clotting and proteolytic enzymes (cardosins) and their specificity towards peptide linkages are also described. Cheeses produced in the Iberian Peninsula using Cynara L. as coagulant are documented. Cynara L. is still the most used vegetable coagulant in cheesemaking, and also the most investigated. However, much work remains to be done to understand its action during cheese maturation and further characterization.
A computational fluid dynamics design of a carbon dioxide sorption circulating fluidized bed

A kinetic theory based hydrodynamic model with experimentally determined sorption rates for reaction of CO2 with K2CO3 solid sorbent is used to design a compact circulating fluidized bed sorption-regeneration system for CO2 removal from flue gases. Because of high solids fluxes, the sorber does not require internal or external cooling. The output is verified by computing the granular temperatures, particle viscosities, dispersion, and mass transfer coefficients. These properties agree with reported measurement values except the radial dispersion coefficients, which are much higher due to the larger bed diameter. With the solid sorbent prepared according to published information, the CO2 removal percentage at the riser top is 69.16%. To improve the CO2 removal, an effort is needed to develop a better sorbent or to simply lower the inlet gas velocity to operate in a denser mode, leading to a larger system. Also, the effect of temperature rise on the removal efficiency is investigated. © 2010 American Institute of Chemical Engineers AIChE J, 2010
Straight and Smooth Etching of GaN (1100) Plane by Combination of Reactive Ion Etching and KOH Wet Etching Techniques

GaN striped structures along the <11 20 > and <1 100 > directions were fabricated by a combination etching technique, consisting of reactive ion etching followed by KOH wet etching. After wet etching, the sidewalls of the striped structures along the <11 20 > direction became very smooth and straight, compared with normal wet etching and dry etching. From the differences of the etching along the <1 100 > direction, it was found that etching mainly occurs in the (1 100) plane. This phenomenon can be explained by the action of OH- ions, which are repelled by N dangling bonds on the surface and which attack Ga back bonds as well as the mechanism of (000 1) polar GaN etching.
Geomagnetically Induced Currents, a space weather hazard. Case study - Europe under intense geomagnetic storms of the solar cycle 23

The interaction of the solar wind and heliospheric magnetic field with the magnetosphere and ionosphere results in variations of the geomagnetic field that induce hazardous electric currents in grounded technological systems (electric power and hydrocarbon transportation networks), the so-called geomagnetically induced currents (GICs). In order to evaluate the hazard induced on the European continent, we present a study of the surface electric field induced by 16 intense (Dst < -150 nT) geomagnetic storms, based on the analysis of the geomagnetic records from the European network of observatories, study that tend to solve the geophysical part of the problem. The evolution during storm development and the sources of the disturbance field are explored in case of the largest geomagnetic storm in the cycle 23 (Dst = -422 nT, November 20-21, 2003), and the geographical distribution of the maximum induced surface geoelectric field over Europe by the 16 storms considered in the study is presented. As source proxies, the Dst geomagnetic index, showing the disturbed field produced by the magnetospheric ring current at the geomagnetic equator, the AL geomagnetic index, showing the disturbed field produced by the ionospheric electrojet at auroral latitude, and the PC geomagnetic index, showing the disturbed field produced by the polar cap current, were examined. © 2016 BBSCS RN SWS. All rights reserved
Effects of surface structures of MgO(100) single crystal substrates on ferroelectric PbTiO3 thin films grown by radio frequency sputtering

Effects of surface structures of MgO(100) single crystal substrates on the growth of PbTiO3 thin films by radio frequency magnetron sputtering have been investigated. First, the surface structures of the substrates prepared by cleaving, polishing, and annealing were characterized using Rutherford backscattering spectroscopy combined with channeling, surface sensitive x‐ray scattering, and atomic force microscopy. We found a strong correlation between the surface structures and the growth of the thin films. The film on the cleaved substrate was not uniform and its crystallinity was poorer than that on the polished or the annealed substrates due to the presence of large cleavage steps, whereas better epitaxiality was found on the annealed substrate than on the polished substrate. Favorable effects of thermal annealing after polishing have been explained based on surface step rearrangements, damage removal, and improvement in surface flatness by the thermal annealing treatment.