Miracle-dz/UniFAR-FTUs huggingface dataset:
Unexpected isotope effect on the spin transition of the coordination polymer Fe(C5H5N)2[Ni(CN)4]

The two-dimensional coordination polymer spin-crossover compound Fe(pyridine)2[Ni(CN)4] (1) and its isotope substituted analogues Fe(pyridine-D5)2[Ni(CN)4] (2) and Fe(pyridine-15N)2[Ni(CN)4] (3) have been synthesised and the isotope effect on the thermal spin-crossover behaviour has been studied using magnetic susceptibility, 57Fe Mossbauer, Raman and calorimetric techniques. All these methods confirmed that upon isotope substitution—contrary to previous observations—the spin transition temperature shifted downwards from 202 to 194 K. The theoretical analysis of spectroscopic data has revealed that this shift was a result of a subtle balance between different vibrational and electronic factors.
Antibody—antigen interactions studied by means of Raman spectroscopy

The percentages of secondary structure of rabbit IgG and anti-IgG in the lyophilized solid and aqueous solution state were obtained from the Raman spectra. The Raman spectrum of the lyophilized IgG-anti-IgG complex was also recorded. The vibrational results indicate that the percentages of secondary structure of IgG do not change when lyophilized IgG is dissolved in water. Moreover, the secondary structure of IgG and of anti-IgG changes only very slightly as a consequence of the complex formation. However, the Raman spectra in the S-S stretching region suggest that some changes in the molecular geometry around the S−S bridges take place as a consequence of the IgG-anti IgG complex formation
A Note on Gravimetric Measurements of Gas-Adsorption Equilibria

Adsorption equilibria of He, Ar, N2, CH4 on several types of activated carbon (AC) and molecular sieves (MS) have been measured at ambient temperature in the pressure range 0 MPa–15 MPa using a microbalance (Sartorius 4104 S). The resulting experimental data on principle only allow to calculate the difference (m–ρfVas) between the net mass adsorbed m, and the buoyancy related volume Vas of the adsorbent/adsorbate system multiplied by the density of the (fluid) adsorptive ρf. To determine simultaneously m and Vas, the data are fitted to an analytic adsorption isotherm m = m (ρf,T) of generalized Langmuir-Freundlich type and/or Dubinin-Radushkeviz type, and to one of four different models for the volume Vas, including the so-called helium volume, this quantity considered to be constant. – The two times four adsorption isotherms (AI) resulting in this way do not differ much for low pressures (p < 1 MPa), however tend to differ considerably at higher pressures, the helium volume related AI leading to thermodynamic inconsistencies! As a result it can be stated that the buoyancy related apparent volume Vas of a porous adsorbent/adsorbate system strongly depends on the adsorptive used, i.e. on the size of its molecules, and also, to lesser extend, on the amount of mass adsorbed. Consequently, Vas should not simply be identified with the helium volume but instead specified for different adsorptives and pressure ranges used in industrial adsorption processes.
Glass transition breadths and composition profiles of weakly, moderately, and strongly segregating gradient copolymers: experimental results and calculations from self-consistent mean-field theory

Gradient copolymers are prepared from comonomer systems with a range of segregation strengths and homopolymer glass transition temperature (Tg) differences to explore the breadths that can be achieved by their single, continuous glass transition regions compared to random and block copolymers. A variety of chain architectures are synthesized using semibatch nitroxide-mediated controlled radical polymerization, including linear gradients, sigmoidal gradients, blocky gradients, and blocky random cases. The derivative of the differential scanning calorimetry heat curve is used to extract Tg breadths (ΔTgs). For the first time, these Tg breadths are compared against values derived from nanophase separation levels predicted by self-consistent mean-field theory and found to be in good accord. In moderately segregating systems (styrene (S)/n-butyl acrylate and S/tert-butyl acrylate), ΔTg may be tuned dramatically via gradient structure and molecular weight; e.g., a Tg breadth exceeding 100 °C, or >65% of the hom.
Determination of the barriers to internal rotation in ONOOX (X = H, Cl) and characterization of the minimum energy conformers

Because of the interest in their possible formation in the atmosphere, the conformational potential energy surfaces of ONOOH (peroxynitrous acid) and ONOOCl (chlorine peroxynitrite) were thoroughly investigated using correlated methods of electronic structure theory. Three conformers of ONOOH were found to be minima, the lowest in energy a planar five-membered hydrogen-bonded ring, predicted to lie 1 kcal mol[sup [minus]1] below the form with a cis ONOO arrangement and perpendicular OH bond. Although predicted to be 3 kcal mol[sup [minus]1] higher in energy than the planar conformer (in the gas phase), the identity of the form previously observed in matrix isolation experiments is suggested to have a trans ONOO arrangement and perpendicular OH bond, consistent with the experimental assignment. The chlorine analog ONOOCl was found to have two minimum energy conformers, the cis-perpendicular form predicted to lie 2 kcal mol[sup [minus]1] below the trans-perpendicular form. Rotation about the peroxide bond is much more hindered in ONOOCl than in ONOOH: Calculations of physical properties, including geometrical structures and vibrational spectra, were made at the MP2 level of theory using basis sets ranging in quality from 6-31G(d) to 6-311G(2df,2p). Thermochemical tabulations based on G2 and G2(MP2) energies were made for ONOOH and ONOOCl,more » respectively. Values of [Delta]G(300 K), for production of the lowest energy conformers from reactants XO + NO[sub 2], are predicted to be [minus]12 kcal mol[sup [minus]1] (X = H) and +3 kcal mol[sup [minus]1] (X = Cl). 23 refs., 3 figs., 6 tabs. « less
Evaluating accessibility of small communities via public transit

Accessibility to and from urban centres allows small communities’ dwellers to participate in primary activities and use essential services that are not available on-site, such as educational, work and medical services. Public transport networks are supposed to enhance accessibility and pursue equity principles, overcoming socio-economical differences among people that can exacerbate during crisis. In this paper a methodology is proposed and implemented to assess small communities’ accessibility via public transit. A metric is defined based on the calculation of total travel time, taken as a proxy of travel impedance, with consideration of in-vehicle time, schedule delay and users’ arrival and departure preference curves (i.e. time-of-day functions). A “rooftops” model is specified and implemented under the assumption that travellers cannot accept (scheduled) late arrival or early departure time penalties before and after the participation in their activities in the main urban centre, as many activities rarely admit time-flexibility. Also, a public transport specific impedance factor (PTSIF) is proposed, in order to account for travel impedance determinants, which are a consequence of service scheduling and routing decisions and not due to inherent geographical and infrastructural disadvantages affecting car users too. An application of the methodology for the city of Cesena, Italy, and 90 surrounding small communities is presented. The city is served by train and bus services. Assessment of small communities' accessibility based on both total travel time and PTSIF is presented and discussed. This practice-ready quantitative method can help transport professionals to evaluate impacts on small communities’ accessibility in light of public transport service changes or reduction. Quantitative approach to support strategic decisions is needed, for example, both to assess public transport strengthening politics against depopulation of rural and marginal mountainous areas and to mitigate the effects of possible increasing concentration of services towards high-demand lines, which may follow as a consequence of budget cuts or contingencies, such as vehicle capacity reductions required by sanitary emergencies.
Comparative Studies on Structural, Optical, and Textural Properties of Combustion Derived ZnO Prepared Using Various Fuels and Their Photocatalytic Activity

Pure mesoporous nanosized ZnO samples have been synthesized by combustion synthesis method using different type of fuels such as citric acid, dextrose, glycine, oxalyl dihydrazide, oxalic acid, and urea. All these samples were found to have the standard hexagonal wurtzite structure with the lattice constants a and c having values 3.25 A and 5.21 A, respectively. The diffuse reflectance spectra of the prepared samples have shown the maximum absorption of light in the UV region stating that these catalysts can be used as photocatalysts. The BET surface area measurements of the prepared catalysts were found to vary according to the equivalence ratio. The presence of pronounced hysteresis in N2 adsorption–desorption isotherm curves indicated the three-dimensional network arrangement of pores in the ZnO samples prepared using dextrose and urea as fuels. The photodegradation ability of the various synthesized photocatalysts was tested for the photodegradation of an azo dye, namely, orange G dye solution. ZnO ph.
Scale-Up of Polymerization Process: A Practical Example

The scale-up/-down of polymerization reactors has to deal with large viscosity changes during the process, addressing mass- and heat-transfer issues. A practical example on scale-up of styrene and methyl methacrylate free radical bulk and solution polymerization is presented. The main critical parameters are mixing at molecular level (micromixing) and heat removal capacity. The operating parameters being kept constant are: reaction conditions (temperature, pressure, chemistry) and thus the reaction time. A pilot plant issued from scale-down of possible industrial sizes was developed to represent, at best, larger scales. The main parameter being scaled-up is the heat removal capacity, which has to be maintained constant among the different sizes. New concepts are adapted to dissipate the mixing energy where it is the most suitable, and the final step is the scale-up/-down strategy. Another issue addressed in this contribution is the need for in-line analytics that could operate at different plant scales a.
SALES ANALYSIS OF E-COMMERCE USING DATA MINING TECHNIQUES

In the emerging global economy, E-commerce is a strong method for financial development. The fast growth in usage of Internet and Web-based applications is decreasing operational costs of large enterprises, extending trading opportunities and lowering the financial barriers for active ecommerce participation. Many companies are reorganization their business strategies to attain maximum value in terms of profits as well as customer’s satisfaction. Data mining (DM) is used to attain knowledge from available information in order to help companies make weighted decisions. An organization needs to invest only on the group of products which are frequently purchased by its customers as well as price them appropriately in order to attain maximum customer satisfaction. The objective of this paper is to evaluate, propose and improve traditional pricing strategies by using web mining techniques to collect information from e-commerce websites and apply data mining methods to induce and extract useful information out of it.
Removal of methyl orange from aqueous solutions by magnetic maghemite/chitosan nanocomposite films: Adsorption kinetics and equilibrium

Magnetic maghemite (γ-Fe2O3)/chitosan nanocomposite films were prepared by solution casting method and characterized by Fourier transform infrared spectra, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction. Batch adsorption experiments were carried out utilizing the composite films to adsorb a typical azo dye, i.e., methyl orange (MO) from aqueous solutions. The effects of adsorbent dosage, solution pH, coexisting anions, and temperature were studied. Adsorption kinetic was verified by pseudo-first-order and pseudo-second-order kinetic models. Results indicated that the rate of dye adsorption followed pseudo-second-order kinetic model for the initial dye concentration range studied. MO adsorption onto magnetic γ-Fe2O3/chitosan composite films was better described by Langmuir isotherm. Thermodynamic studies showed that MO adsorption was exothermic and spontaneous in nature. Because magnetic maghemite/chitosan nanocomposite films could be recovered conveniently and possessed of excellent adsorptive property, it can be developed as an economical and alternative adsorbent to decolorize or treat dye wastewater. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A whole-air relaxed eddy accumulation measurement system for sampling vertical vapour exchange of elemental mercury

An apparatus relying on relaxed eddy accumulation (REA) methodology has been designed and developed for continuous-field measurements of vertical Hg0 fluxes over cropland ecosystems. This micro-meteorological technique requires sampling of turbulent eddies into up- and downdraught channels at a constant flow rate and accurate timing, based on a threshold involving the sign of vertical wind component (w). The fully automated system is of a whole-air type drawing air at a high velocity to the REA sampling apparatus and allowing for the rejection of samples associated with w-fluctuations around zero. Conditional sampling was executed at 10-Hz resolution on a sub-stream by two fast-response three-way solenoid switching valves connected in parallel to a zero Hg0 air supply through their normally open ports. To suppress flow transients resulting from switching, pressure differentials across the two upstream ports of the conditional valves were minimised using a control unit. The Hg0 concentrations of the up- and downdraught channel were sequentially (each by two consecutive 5-minute gas samples) determined after enhancement collection onto gold traps by an automated cold vapour atomic fluorescence spectrophotometer (CVAFS) instrument. A protocol of regular reference sampling periods was implemented during field campaigns to continuously adjust for bias that may exist between the two conditional sampling channels. Using a 5-minute running average was conditional threshold, nearly-constant relaxation coefficients (βs) of ~0.56 were determined during two bi-weekly field deployments when turbulence statistics were assured for good quality, in accordance with previously reported estimates. The fully developed REA-CVAFS system underwent Hg0 flux field trial runs at a winter wheat cropland located in the North China Plain. Over a 15-d period during early May 2012, dynamic, often bi-directional, fluxes were observed during the course of a day with a tendency of emission (Hg0 median flux of 77.1 ng m−2 h−1) during daytime and fluctuation around zero (Hg0 median flux of 9.8 ng m−2 h−1) during nighttime.
Degradation of cellulosic and hemicellulosic substrates using a chelator-mediated Fenton reaction

The involvement of catechol and hydroxamate chelators, along with hydrogen peroxide and Fe3+, in the degradation of cellulosic and hemicellulosic substrates was examined with the purpose of improving our current knowledge of the non-enzymatic mechanisms involved in wood biodegradation by fungi. It could be demonstrated that a catechol chelator-mediated Fenton reaction not only clearly degraded hemicellulosic substrates but also significantly accelerated and increased the effectiveness of degradation reactions. On the other hand, when a hydroxamate chelator-mediated Fenton reaction was used, an inhibitory effect was observed. When cellulosic substrates underwent a chelator-mediated Fenton reaction, no significant difference in degradation was observed between catechol and hydroxamate chelator-mediated reactions. However, a catechol-mediated reaction did accelerate the degradation of cellulosic substrates at the beginning of reactions. In addition, it was observed that with a chelator-mediated Fenton reaction, oxidation of cellulose proceeds depolymerization. Copyright © 2005 Society of Chemical Industry
Fluorescence and photobleaching studies of methylene blue binding to DNA

Complexes of methylene blue with DNA are characterized by time- resolved fluorescence spectroscopy and transient photobleaching methods. At least four, and probably five, spectroscopically distinct binding sites have been identified. Three of these (components 1, 2, and 3B) dominate the fluorescence decay at low ionic strength and have fluorescence lifetimes significantly different from that of the free dye. With increasing ionic strength a fourth component (3A) appears at the expense of components 1 and 3B. Component 3A exhibits two subcomponents with different degrees of shielding from O2 quenching of its triplet state. The relative amplitudes of the components at low ionic strength are strongly dependent on the composition of the DNA, and independent of superhelix density. Hence, it is inferred that components 1, 2, and 3B represent binding to different base pair steps, and that all of these components represent intercalation sites that unwind the DNA to the same degree. Component 3A is apparently not intercalated. From plots of the relative photobleach amplitudes versus the relative fluorescence intensities, we infer that the triplet yield and photobleach amplitude are dominated by components 3A and/or 3B under nearly all conditions. Our results are used to discuss the suitability of methylene blue as the extrinsic probe in transient photodichroism experiments.
The Inescapability of Uncertainty

As big data becomes a larger presence in our lives, we increasingly rely on artiﬁcial intelligence to help us make decisions. And why not? There is a certain appeal to the idea that clever algorithms and troves of data will let us tame the uncertainty in our lives. In this position paper, we examine three properties of AI systems: 1) AI is built on assumptions about data and desired system behavior; 2) algorithms can have unfair consequences; and 3) algorithmic predictions can be hard to interpret. We argue that no matter how clever our algorithms are or how much data we collect, it will never be possible to fully escape uncertainty. Therefore, rather than treating AI systems as a way to automatically make our decisions for us, freeing us from dealing with the uncomfortable reality of uncertainty, it is smarter to treat AI systems as a way to leverage the complementary strengths of people and machines.
Photothermal ionization spectroscopy of shallow nitrogen donor states in 4H–SiC

Photothermal ionization spectroscopy (PTIS) measurements were carried out on a free-standing, high purity and high quality 4H–SiC epitaxial layer at various temperatures. The two step photothermal ionization process is clearly reflected in the temperature dependence of the photoconductivity. The PTI spectrum at a temperature of 25.6 K exhibits one order of magnitude higher energy resolution than the infrared absorption spectra of 4H–SiC bulk material. It reveals five strong, well resolved electronic transition lines associated with the shallow nitrogen donor. The ionization energy of the shallow nitrogen donor is deduced to be 60.2±0.5 meV based on experimental results. Furthermore, PTI magnetospectroscopy measurements were performed to investigate the symmetry properties of these transitions in Faraday configuration. No linear Zeeman splitting is observed, however, these lines show a diamagnetic shift. It indicates that the excited states of the shallow nitrogen donor are nondegenerate at zero magnetic f.
MALAYSIAN JOURNAL OF CONSUMER AND FAMILY ECONOMICS 175 Store Image Attributes and Customer Satisfaction of Convenience Store and Implications on Retail Innovation: The Malaysian Shopper Experience

New technology ideas have continued to change the retail industry landscape spurring innovation across the convenience store industry. Convenience stores (Cstores) are now considered as the fastest-growing retail vertically. Retailers are increasingly challenging the notion that c-stores should not be just mere pit stops. Modern c-stores are becoming convenience destinations. Recent developments witness new C-store chains popping up in Malaysia such as KK Mart, Happy Mart, Orange Mart, Family Mart and Irispay to compete along with conventional ones such as 7-Eleven and those stores subsumed with a petrol station. New C-stores have features beyond standard convenience offerings with digital technology to capture customer attention and drive store traffic. New players are expanding its brick-andmortar presence, just like how Amazon shook up the C-store sector in 2017 with new checkout-free, ultra-convenient shopping experience. In the wake of this new retail innovation, how will other C-store retailers position themselves one step ahead of the game? This paper examines store image attributes influencing customer satisfaction of C-stores amongst the conventional one. These stores are considered as plain, outdated and at the boredom stage of its business lifecycle. C-stores may need to deliver a new experience that today’s digital consumers are looking for. The methodology utilized a survey questionnaire approach on 255 shoppers together with store observation and personal interview at a C-store franchise chain. Findings found personnel, pricing, merchandising and product assortment as predictors of customer satisfaction of C-stores. Findings had managerial implications for C-store retailers focusing on what innovations in-store image attributes can impact competition. Knowing how quick consumers are embracing technological advances in this C-store sector is imperative to stay ahead in this game.
δ15N Values of sorghum grains harvested on a vertisol in the semi-arid tropics were positively related to doses of fertilizer N but negatively with the frequency of legume cultivation

Abstract The relation between δ15N values of sorghum grains grown on Alfisol or Vertisol fields and the fields' cropping and N-fertilizer histories was investigated. Fields were cultivated with legumes or cereals at different frequencies for 10 y, prior to sowing of sorghum. During that period, the fields for study were amended with different N-fertilizers at rates ranging between 236 and 1,472 kg N ha-1. The δ15N values were markedly different between the two soil types. In the Vertisol fields, the grain δ15N values were positively correlated with the cereal-cropping frequency and amounts of applied fertilizers, but negatively correlated with the legume-cropping frequency. Such correlations were not observed in the Alfisol fields. It was concluded that only the amount of applied fertilizer influenced the δ15N values of sorghum grains, and that this effect was caused by the slight alkalinity of the Vertisol.
An Information-Theoretic Perspective on Credit Assignment in Reinforcement Learning

How do we formalize the challenge of credit assignment in reinforcement learning? Common intuition would draw attention to reward sparsity as a key contributor to difficult credit assignment and traditional heuristics would look to temporal recency for the solution, calling upon the classic eligibility trace. We posit that it is not the sparsity of the reward itself that causes difficulty in credit assignment, but rather the \emph{information sparsity}. We propose to use information theory to define this notion, which we then use to characterize when credit assignment is an obstacle to efficient learning. With this perspective, we outline several information-theoretic mechanisms for measuring credit under a fixed behavior policy, highlighting the potential of information theory as a key tool towards provably-efficient credit assignment.