Miracle-dz/UniFAR-FTUs huggingface dataset:
Simulations of Deformation Processes in Energetic Materials

The sensitivity of energetic materials has been studied extensively for more than half a century, both experimentally and numerically, due to its importance for reliable functioning of a munition and avoidance or mitigation of accidents (Bowden & Yoffe, 1952). While the shock initiation of an explosive under nominal conditions is relatively well understood from an engineering perspective, our understanding of initiation due to unintended stimuli (weak shock or fragment impact, fire, damaged explosive charge) is far less complete. As an example, one cannot exclude the ignition of an explosive due to mechanical deformation, potentially leading to lowor even high-order explosion/detonation as a consequence of mechanical stimuli with strain rates and pressures well below the shock sensitivity threshold. During the last two decades there has been an increased interest in the scientific community in understanding initiation sensitivity of energetic materials to weak insults. A relationship between energy dissipation and rate of plastic deformation has been developed for crystalline energetic materials (Coffey & Sharma, 1999). Chemical reactions are initiated in crystalline solids when a crystal-specific threshold energy is exceeded. In this sense, initiation is linked to the rate of plastic deformation. However, practical energetic materials are usually heterogeneous composites comprised of one or more kinds of energetic crystals (the filler, for which the mass fraction can exceed 90%) bound together with a binder matrix that often consists of several different polymer, plasticizer, and stabilizer materials. Clearly, the mechanical behavior of these polymer-bonded (plastic-bonded) explosives (PBXs) is far more complicated than for neat crystals of high explosive. It is necessary in realistic constitutive modeling of energetic compositions to incorporate features reflecting the complex, multiphase, multiscale structural, dynamical, and chemical properties; see, for example, Bennett et al., 1998, and Conley & Benson, 1999. The goal in constitutive modeling is to bridge the particulate nature at the mesoscale to the mechanical properties at the macroscale. The macroscale deformations applied to PBX composites in experiments are generally not the same as the local deformation fields in a component crystal within the composite. This has been demonstrated using grain-resolved mesoscale simulations wherein the individual grains and binder phases in a PBX are resolved within a continuum simulation framework.
Chloride ion recognition using thiourea/urea based receptors incorporated into 1,3-disubstituted calix[4]arenes

New calix[4]arene derivatives (3–5, 7–8) of cone and 1,3-alternate conformations possessing thiourea/urea moieties have been synthesized and examined for their anion recognition abilities towards different anions like fluoride, chloride, bromide, iodide, nitrate and acetate by 1H NMR and UV-Vis spectroscopy. Fitting the changes in the absorption spectra using nonlinear regression analysis indicates that all these compounds have strong binding affinity for chloride ions. The stoichiometry of the hydrogen bonded complexes is 1 : 1 (H : G) for receptor 3–5, while it is 2 : 1 (H : G) with 7–8. Chloride ion selective electrodes (ISEs) were also formed which showed excellent selectivity over all other anions tested.
New bound electronic states of NH

Ab initio MRD-CI electronic structure calculations were carried out on the NH+ cation. A basis set of DZ + POL quality augmented with Rydberg and bond functions was employed, together with an extensive treatment of electron correlation. We find four new bound electronic states of NH+, namely, three doublets (2Δ, 2Σ+, 2Σ+) and one sextet (6Π). A fifth bound electronic state, a quartet (4Π) that was reported schematically in an early SCF study (Liu, H. P. D.; Verhaegen, G. J Chem Phys 1970, 53(2), 735), is calculated for the first time over a wide range of NH distances. Electronic energies, potential energy curves, and spectroscopic constants are reported for these five states. Vertical and adiabatic excitation and ionization energies are reported, as well as vertical de-excitation energies for emission from the novel states to lower-lying bound states. The potential energy curve of NH2+ (X1Σ+) was also calculated to aid in the discussion of a Rydberg bound state of NH+. It is hoped that the information reported in this article will be helpful in guiding the experimental detection of these species. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Mathematical models for the anodization conditions and structural features of porous anodic Al{sub 2}O{sub 3} films on aluminum

A developed strict kinetic model for the growth of porous anodic Al{sub 2}O{sub 3} films was employed to the experimental results obtained at different bath temperatures and current densities of Al anodization. Treatment of the values of parameters involved in the kinetic equation showed that the pore/cell surface density depends only on current density, the pore base diameter depends only on bath temperature, and the equations ln n = p ln J + p{double_prime} and ln D{sub b} = g ln T + g{double_prime} accurately apply. By using these equations, mathematical models for other structural features were also formulated describing their dependence on the anodization conditions.
A DFT and HF quantum chemical study of the tin nanocluster [(RSn)12O14(OH)6]2+ and its interactions with anions and neutral nucleophiles: confrontation with experimental data

Calculations of traditional wave function and DFT based reactivity descriptors are reported for the nanocluster [(RSn)12O14(OH)6]2+ (R = CH3) in order to get insight into the factors determining the exact nature of its interactions with anions or neutral nucleophiles (F−, Cl−, OH−, H2O, acetone, DMSO). Two levels of calculation (Hartree–Fock and DFT) were used in this study, giving the opportunity to compare the performance of both aproaches. As a whole the HF and DFT results, despite some numerical differences, are qualitatively and in most cases quantitatively similar, since no interchanges in the sequences are found. Calculated charge distributions indicate that the hexacoordinated tin atoms are expected to be harder, the pentacoordinated ones softer. This result is confirmed by the condensed local softness and experimental observations provided by the literature (X-ray, 119Sn NMR), thereby matching predictions made on the basis of the HSAB principle. Molecular electrostatic potential (MEP) calculations further confirm this selectivity, indicating that nucleophiles will approach preferentially the macrocation around the poles rather than at the equator of the cage. Calculated stabilization energies indicate that the charged (F−, Cl− and OH−) and uncharged (DMSO, acetone and water) nucleophiles tested all interact preferentially with the cage pole region around the hexacoordinated tin atoms. This feature appears related to the electrostatic nature of the interaction for the charged nucleophiles and to the tendency, for all the nucleophiles, to form hydrogen bridges with the μ2-OH moieties. The basicity of the three types of oxygen atoms [μ2-OH, μ3-O(I), μ3-O(P)] present in [(RSn)12O14(OH)6)]2+ has been addressed by protonation energy and MEP calculations, taking into account accessibility factors not represented by atomic charges. Summarizing, it turns out that the hardness/softness properties of tin atoms are modulated by their coordination; however, the sole consideration of these quantities is not sufficient to predict in all cases the strength and orientation of the interaction between various nucleophiles and the cluster, since electrostatic interactions and H-bonding play a major role.
Scale Development for The Utilization Of Information And Communication Technologies

Bu calismanin amaci, ilkogretim ikinci kademe ogrencilerinin bilisim teknolojilerinden yararlanma duzeylerini olcmek icin gecerli ve guvenilir bir olcek gelistirmektir. Olcek yapisinin belirlenmesi amaciyla, 157 ilkogretim ikinci kademe ogrencisi ornekleme alinmistir. Bu uygulama ile olcegin yapisina uymayan maddelerin olcekten cikarilmasiyla elde edilen olcegin son hali gecerlik ve guvenirlik testlerinin yapilmasi amaciyla 734 ilkogretim ikinci kademe ogrencisine uygulanmistir. Dortlu likert tipte hazirlanan olcegin ilk formunda yer alan 45 madde yapilan uygulama ve analizler sonunda 18 maddeye indirilmistir. Olcegin, bilgi edinme, arastirma-inceleme, iletisim, oyun-eglence ve kendini ifade etme seklinde bes faktoru oldugu belirlenmistir. Olcegin tamaminin cronbach α guvenirlik katsayisi 0.85 olarak hesaplanmistir.
Improved fabrication of micro air-channels by incorporation of a structural barrier

The fabrication of air-channels for microelectromechanical systems and microfluidic devices using polynorbornene and polycarbonates as thermally or photolitically decomposable materials to form air-gaps in dielectric materials has been reported. In this study, the incompatibility of some overcoat polymers with the sacrificial materials was addressed. SiO2 was used as a barrier layer for the fabrication of single- and multi-layer air-channels via different sacrificial and overcoat materials. The structural rigidity of SiO2 mitigates problems associated with overcoat polymers that can easily deform at the processing temperature (overcoat cure or sacrificial decomposition temperature). The chemical inertness and low permeability of SiO2 allows the use of solvent-cast polymers, for which the solvents would have otherwise dissolved the sacrificial material.
Design Theory for Screw Geometry in a Briquette Press

This paper focuses on the structural design of screw tools in briquetting presses used for the production of solid, high quality, bio fuels. The primary objective is to analyse the screw tool geometry and determine a procedure for its design, specifically the theory involved with the pressing tool and force relations which are necessary for the verification of the proposed tool geometry and its strength analysis. In designing the main drive of the press, procedures for determining frictional performance of the screw press are used. Familiarity with the above mentioned procedures forms the basis for research into new tools in screw briquetting presses that will improve the service life and competitiveness of the technology.
Microwave-assisted Extraction of Monoterpenols in Must Samples

The microwave-assisted extraction of five terpenic compounds associated with the varietal aroma of Vitis vinifera was developed and optimized by means of three- and two-level factorial designs. Four variables (extractant solvent volume, extraction temperature, amount of sample and extraction time) were considered as factors in the optimization process. The results suggest that the solvent volume and the amount of sample to be extracted are statistically significant for the overall recovery of the studied species, although compromise conditions have to be established in order to avoid losses of the extracted compounds in the concentration steps needed when the solvent volume increases. The optimum conditions established were applied to the extraction of real grape must samples and compared with the results given by conventional alternative procedures.
Rate of Hydroxypropylation of Starches as a Function of Reaction Time

To determine the course of the hydroxypropylation reaction as a function of reaction time, waxy corn, normal corn, potato, and wheat starches were reacted with propylene oxide under normal reaction conditions. Amounts of leached material and MS values of both leached and granular molecules were determined over the course of reaction. For waxy and normal corn starches, the extent of reaction increased linearly from 0 to 12 h, after which the reaction proceeded at an ever decreasing rate, reaching zero at about 30 h of reaction. The initial rate of reaction was determined by reacting waxy corn starch with a greater amount of propylene oxide (10×normal concentration) so that there would be no slowing of the reaction due to loss of reagent. Results confirmed that the initial reaction rate was linear. The hypothesis that, as derivatization proceeds, granules are opened up, resulting in ever increasing rates of reaction was not substantiated. Amounts and MS values of leached molecules from waxy and normal corn starches increased continuously over the course of the reaction. For potato and wheat starches, MS values of the granular starch also increased continuously over the entire reaction period. Amounts of leached molecules from potato starch were greater than those from wheat starch, with the amount leached at 30 h from potato starch being slightly more than that from normal and waxy corn starches and that from wheat starch being considerably less.
Cu(II)−Azabis(oxazoline) Complexes Immobilized on Magnetic Co/C Nanoparticles: Kinetic Resolution of 1,2-Diphenylethane-1,2-diol under Batch and Continuous-Flow Conditions

Carbon coated cobalt nanoparticles were tagged with azabis(oxazoline)−copper(II) complexes utilizing a copper(I)-catalyzed azide/alkyne cycloaddition (CuAAC) reaction, and the efficacy of the resulting nanomagnetic catalyst was tested in the kinetic resolution of racemic 1,2-diphenylethane-1,2-diol via asymmetric monobenzoylation. The novel semiheterogeneous catalyst was examined under batch conditions and in a continuous flow-type reactor. The extremely high ferromagnetism of the cobalt cores not only facilitates the recycling of the nanobeads via magnetic decantation in the batch reactions but also enables a novel continuous flow-reactor design: This further allowed efficient agitation and containment of the particles to occur without the need for sophisticated separation strategies such as nanofiltration.
Modeling and simulation of a bubbling SO2 absorber with granular limestone slurry and an organic acid additive

The absorption of SO 2 into limestone slurry containing suspended reactive particles was performed in a bubble reactor with continuous feeding of both gas and liquid phases at a constant pH and high temperature (50°C). An absorption model with a reaction plane based on the film model was developed. The effect of limestone particle size, concentration, acetic acid additives, and inlet SO 2 concentration on the concentration distribution of chemical species in the liquid film and SO 2 absorption rate were simulated. Increasing the concentration of limestone slurry, adding acetic acid additives into the system or decreasing the limestone particle size or inlet SO 2 concentration caused the reaction plane in the liquid film to shift towards the gas-liquid interface. Model and experimental results were compared, and it was shown that the model fits the experimental data well.
A Chemorheological Study on the Curing of Thermosetting Resins

A chemorheological viscosity model based on the free volume theory and a dimensionless curing time (t/t grl ) was used to study the complex viscosity changes during the curing of thermosetting unsaturated polyester (USPE) and epoxy resins. The model has five parameters (C 1 , C 2 , C 3 , N, and t gel ) to be determined experimentally. C 1 and C 2 are material constants determined by the complex viscosity/temperature data of neat resin, and C 3 can be calculated from C 1 , C 2 , and the temperature. N is independent of the temperature and only depends on the type and the concentration of initiator or curing agent used. The experimental correlation for N was obtained as a function of the concentration of initiator for USPE resin. The gel time, T gel , was expressed as a function of the temperature and the initial concentration of the initiator. It was observed that model predictions of the complex viscosity changes in both isothermal and nonisothermal curing of USPE and epoxy resins agree well with experimental results. The predicted values of the temperature and the time at the minimum complex viscosity and at the gelation point during nonisothermal curing also agreed well with experimental results
Solution thermodynamics of naproxen in some volatile organic solvents

The thermodynamic functions Gibbs energy, enthalpy and entropy for the solution processes of naproxen (NAP) in four volatile organic solvents were calculated from solubility values obtained at the temperature interval from 293.15 to 313.15 K. NAP solubility was determined in ethyl acetate, acetone, dichloromethane and acetonitrile, as pure solvents. The respective thermodynamic functions for mixing and solvation processes and the activity coefficients for the solute were also calculated. The NAP solubility decreases in the order, Acetone > AcOEt > DCM > AcNit. In addition, the thermodynamic quantities relative to the transfer process of this drug from cyclohexane to the organic solvents were also calculated in order to estimate the contributions due to hydrogen-bonding or other dipolar interactions. The results were discussed in terms of solute–solvent interactions.
Methods of Preparation and Nutritive Value of Some Dishes Consumed in the West Region of Cameroon

2 Abstract: This study deals with the description of the methods of preparation and the nutritive value of some dishes consumed in the West region of Cameroon. Theses dishes are prepared from potatoes, yams, cassava, unripe bananas, maize, soybeans, beans, peanuts, egusi seeds and green leafy vegetables. The contents in moisture, ash, proteins, lipids, fibres and carbohydrates were determined by standard AOAC methods. The results obtained are expressed in g/100 g fw for moisture and g/100 g dw for ash, proteins, lipids, fibres and carbohydrates. The moisture content ranges from 43 (Tag bankun) to 96 (Na'm pfeu); ash, from 2.2 (Poumseing djap mtom) to 17.8 (Na'm pfeu) ; proteins, from 1.5 (Site ngali) to 33 (Sog soja); lipids from, 1 (Na'm pfeu) to 70 (Na'nou'ne); fibres, from 1.8 (Site sembun) to 21.5 (Na'm pfeu) and carbohydrates, from 4.8 (Ndzap njheu') to 69.7 (Poumseing djap mtom). The results show that a higher consumption of Sog soja meals is to be encouraged in order to fight against malnutrition.
Electrochemistry of Uranium in Molten LiCl-KCl Eutectic

The Institute for Transuranium Elements ~ITU! is building up an accurate database of actinide behavior in chloride melts in support of its nuclear fuel reprocessing development program. The electrochemical properties of uranium, dissolved in LiCl-KCl eutectic melt, were investigated by transient electrochemical techniques, such as cyclic voltammetry ~CV! and chronopotentiometry on an inert tungsten electrode. It was shown that U4+ is reduced to U0 by a two-step mechanism corresponding to U4+/U3+ and U3+/U0 transitions. In the 400-550°C s673-823 Kd range, the diffusion coefficients of U3+ and U4+ were similar and equal to: DsU3+d = 13.7 3 10−4 exph−24.2 3 103/RTsKdj and DsU4+d = 5.25 3 10−4 exph−19.8 3 103/RTsKdj cm2 s−1. The apparent standard potentials of U4+/U3+ and U3+/U0 redox systems were Eo*sU4+/U3+dsVd = −1.902 + 0.0006104T sKd vs. Cl2/Cl and Eo*sU3+/U0dsVd = −3.099 + 0.0007689T sKd vs. Cl2/Cl, respectively. Some thermochemical properties sDG*,gd of uranium solutions were also derived from the electrochemical measurements. The Gibbs free energies of dilute solution of UCl3 and UCl4 in the LiCl-KCl were determined to be: DG* = −897.09 + 0.226T sKd and −183.53 + 0.0589T sKd in kJ mol−1, respectively. In the 400-550°C s673-823 Kd range, the activity coefficients g of UCl3 and UCl4 range between 0.3 − 4.5 3 10−3 and 17.1 − 12.7 3 10−3, respectively. © 2005 The Electrochemical Society. @DOI: 10.1149/1.1901083# All rights reserved.
Solvent responsive healing of guar gum and guar gum–multiwalled carbon nanotube nanocomposite gels prepared in an ionic liquid

Guar gum, a galactomannan extracted from the seed of the leguminous shrub Cyamopsis tetragonoloba was found to form a soft elastic gel in 1-butyl-3-methylimidazolium chloride (10% w/v). A nanocomposite gel of the gum with higher strength was prepared in the presence of multiwalled carbon nanotubes (MWCNT). The gels showed healing ability in the presence of three polar aprotic solvents namely acetone, dimethyl sulfoxide and dimethylformamide. However, they did not heal in the presence of acetonitrile. The interactions taking place between the ionic liquid, guar gum and MWCNT were studied by SEM, TEM, FT-IR, powder XRD and rheological property measurements. It was concluded that the electrostatic interactions and the van der Waals interactions among the ionic liquid molecules facilitated the formation of reversible noncovalent bonds and eventually activated the healing in the gel systems through appropriate polymer entanglements. Further, the interactions with the solvents induced favourable polymeric chain mobility required for the healing.
PREPARATION OF CaCu3Ti4O12 USING A WET CHEMICAL METHOD

CaCu3Ti4O12 was synthesized starting from a solution of TiO2 to which Ca and Cu nitrates were added. Due to the differences in the solubilities of the Ca, Cu and Ti, initial variations from ideal stoichiometry and a high solution pH was necessary to obtain stoichiometric CaCu3Ti4O12 precipitates. As precipitated samples were amorphous with CuO phases observed after drying of the precipitates at 300 o C. CaCu3Ti4O12 phases were observed after heat treatment at 1000 o C. XRD studies show the presence of CuO and TiO2 in addition to the CaCu3Ti4O12 for non-stoichiometric samples. Observations under the SEM show the presence of Cu rich and Ti rich phases in addition to the CaCu3Ti4O12.
Influence of oil type on the performance characteristics of a two‐axial groove journal bearing

The use of environmentally adapted lubricants (EALs) is a subject of growing interest to industry as legislation increasingly demands the replacement of mineral oil lubricants. Vegetable‐based fluids are widely seen as providing lubricants from a renewable source, as well as meeting demands for improved biodegradability. However, at present, utilization of such fluids is limited due to their rapid oxidation. EALs produced from other base stocks (i.e. synthetic esters) have been shown to provide performance benefits in hydrodynamic thrust bearings. In the present study, a hydrodynamic journal bearing test rig has been employed to compare the performance of three EALs (a VG32 saturated ester, rapeseed base fluid and a propylene glycol dioleate) relative to three mineral turbine oils (ISOVG32, ISOVG46 and ISOVG68) in the hydrodynamic regime. Results are given in terms of temperature, power loss and minimum film thickness. The impact of oil viscosity index is also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
AMINO ACID ANALYSIS OF PEPTIDES USING HPLC WITH EVAPORATIVE LIGHT SCATTERING DETECTION

A new procedure for the amino acid analysis of peptides has been devised utilizing high performance liquid chromatography (HPLC) with evaporative light scattering detection (ELSD). This procedure eliminates the need for complex derivatization schemes inherent of previous amino acid analysis procedures since the ELSD detects the amino acids directly. This quantitative method detects and separates 18 of the common amino acids in a one hour run time using cation exchange chromatography coupled with ELSD. The procedure was tested by analyzing the hydrolysate of human parathyroid hormone 1–34 (PTH), a synthetic polypeptide. A standard digestion consisting of 24 hour hydrolysis at 110°C in 6 N hydrochloric acid with 3% phenol was used. Validation data reveal this is an accurate and precise procedure for the amino acid analysis of peptides. The sensitivity of this technique is low compared to other state-of-the-art analytical techniques. Detection limits varied depending on the amino acid being analyzed and were.
Synthesis and Structure of 2‐Hydroxy‐2‐Methyl‐1,3‐Bis‐(Methyl 3′,4′,6′‐Tri‐O‐Acetyl‐β‐D‐Glucopyranosid‐2‐yl)‐Imidazolidine‐4,5‐Dione

The title compound was synthesized starting from methyl 3,4,6‐tri‐O‐acetyl‐2‐acetamido‐2‐deoxy‐β‐D‐glucopyranoside, oxalyl chloride, and methyl 3,4,6‐tri‐O‐acetyl‐2‐amino‐2‐deoxy‐β‐D‐glucopyranoside. The crystal and molecular structure of the obtained imidazolidine‐4,5‐dione have been determined by X‐ray analysis as well as 1H and 13C NMR spectroscopy.