Miracle-dz/UniFAR-FTUs huggingface dataset:
Energy Efficiency of an Indirect Thermally Coupled Distillation Sequence

Several thermally coupled distillation sequences have been proposed to improve the thermal inefficiency of conventional distillation sequences. Particularly, for the separation of ternary mixtures, structures that perform a lateral extraction in one of the columns of the integrated arrangement have been shown to provide significant energy savings. The structure of existing sequences, based on conventional distillation columns, might provide the basis for alternate thermally coupled designs. In this paper, it is shown how a thermally coupled system derived from an indirect conventional sequence can provide energy savings through a proper optimization of the interconnecting streams. On propose plusieurs sequences de distillation couplees thermiquement afin d'ameliorer l'efficacite thermique des sequences de distillation conventionnelles. En particulier, pour la separation des melanges ternaires, on montre que les structures qui effectuent une extraction laterale dans l'une des colonnes du dispositif integre permettent des economies d'energie significatives. La structure des sequences existantes, basee sur les colonnes de distillation classiques, pourrait servir de base pour des installations couplees thermiquement alternees. Dans cet article, on montre comment un systeme couple thermiquement concu a partir d'une sequence conventionnelle indirecte peut permettre des economies d'energie par une optimisation adequate des courants d'interconnexion.
Reverse flow operation with reactor side feeding : analysis, modeling and simulation

The novel concept of reverse flow operation with reactor side feeding is studied for selective oxidation of NH 3 to produce either N 2 , N 2 O, or NO. During normal reverse flow operation, where the feeds are alternately introduced from either end of the reactor, the conversion is always lower when compared to steady state, once-through operation at the same residence time. The novel concept of reverse flow operation with reactor side feeding is therefore proposed to avoid the decrease of conversion. The production rate of the desired product can be kept at a high level, which may even exceed the production of normal reverse flow operation and steady state, once-through operation. The reactor behavior was simulated for three regimes (quasi steady state, dynamic, and relaxed steady state) with varying feed positions. The development of spatiotemporal patterns inside the reactor with side feeding shows completely different behavior compared to normal reverse flow operation and steady state, once-through operation, leading to the possibility of conversion and selectivity manipulations. In addition, the proposed concept also indicates better conversion for the dynamic and relaxed steady-state regimes. The influence of shifting the feed positions to the reactor center is most pronounced if the switching time is shorter. This concept also provides an opportunity to prevent the dead gas volume in the center of the reactor if suitable feed positions can be applied. The catalyst effectiveness in this novel concept is therefore much better than during normal reverse flow operation and steady state, once-through operation, particularly in the relaxed steady-state regime.
Refining of Nanopillars Induced by Mn-doping in Epitaxial Ba(Zr,Ti)O3 Thin Films

Microstructures of the epitaxially grown Ba(Zr,Ti)O3 (BZT) and Mn-doped Ba(Zr,Ti)O3 (Mn:BZT) thin films on (001) MgO substrate fabricated by pulsed laser deposition were studied using X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution TEM. The XRD studies showed that both epitaxial thin film structures are c-axis oriented. TEM and high-resolution TEM studies demonstrated that both BZT and Mn:BZT films consist of a continuous epitaxial layer near the interface followed by the formation of twin-coupled nanopillars, united by sharing their {111} or {110} plane as a common plane. The microstructure evolution from the epilayer to nanopillars is accomplished by alternatively introducing {111} and {110} plane twin boundaries, resulting in gradual shrinking/enlarging of the lateral size of the epitaxial grains/twin-coupled nanopillars. The lateral size of the nanopillars in BZT films is about four times larger than that in the Mn:BZT films. The refining of the nanopillars in the Mn-doped films is attributed to enhanced twinning facilitated by the preferential presence of Mn ions on the {110} boundary planes.
Transitional Phase Inversion of Solid-Stabilized Emulsions Using Particle Mixtures

For emulsions containing equal volumes of toluene and water stabilized by nanometer-size silica particles alone, we demonstrate that transitional inversion, from oil-in-water (o/w) to water-in-oil (w/o) and vice versa, can be achieved using mixtures of two particle types of different wettability. Using conductivity, stability, light diffraction, and optical microscopy measurements, we detail three main ways of effecting this which include addition of hydrophilic silica to w/o emulsions stabilized by hydrophobic silica, addition of hydrophobic silica to o/w emulsions stabilized by hydrophilic silica, and varying the weight fraction of one of the particle types at constant total particle concentration. Although both types of emulsion are very stable to coalescence, the stability to creaming of o/w emulsions and to sedimentation of w/o emulsions is least around conditions of inversion, consistent with the average drop sizes displaying a maximum. An increase in the proportion of charged hydrophilic silica res.
Effects of Alkali Pretreatment on Surface Properties and Green Color Conservation of Moso Bamboo (Phyllostachys pubescens Mazel)

Summary Standing bamboo culms have an attractive greenish skin. Once harvested, however, they turn yellow and the color starts to decay. These adverse properties limit their applications and degrade their performance. Chromated copper arsenate (CCA) based preservatives have been reported to be good protectors for preserving the green color of bamboo culms. An alkali pretreatment was required before applying CCA. However, the mechanism of alkali pretreatment on color conservation is not fully understood. In this study, morphology, wettability, chemical and pigment changes of moso bamboo (Phyllostachys pubescens Mazel) were studied after treating with four alkali reagents. The results showed that 2% KOH effectively removed the waxes and capes of silica cells on moso bamboo surface and also increased the surface wettability much better than treatments with 4% K2CO3, 10% K2CO3, 4% Na2CO3, or 4% NaHCO3. The KOH pretreatment also results in a better penetration and reaction with the green color protector (5% Boliden K-33, type-B CCA), and subsequently preserved the green color appearance of moso bamboo.
Design and Synthesis of Novel Aza-Aromatic Host−Guest Complexes: Crystal Structures of 1,7-Phenanthroline with Thiodipropionic and Thiodiglycolic Acids

Aza-aromatic compounds such as 1,10-phenanthroline and 1,7-phenanthroline constitute a new class of hosts involving hydrogen bonds as well as hydrophobic interactions. Crystal structures of 1,7-phenanthroline with thiodipropionic and thiodiglycolic acids are discussed, showing the incorporation of the thiodipropionic acid as a guest molecule in channels of 1,7-phenanthroline and the thiodiglycolic acid as being sandwiched between layers of the aza molecules.
Effect of simultaneous excitation of singlet and triplet excitons on the operation of organic solar cells

Primary steps of exciton formation in organic solar cells are presented here. The rates of absorption of photons to excite singlet and triplet excitons are derived using exciton-photon and exciton-spin-orbit-photon-interaction, respectively, as perturbation operators. In both singlet and triplet absorptions, the rates are found to depend on the absorption energy, excitonic Bohr radius, and the dielectric constant of the donor organic material. Incorporation of heavy metal atoms enhances the exciton-spin-orbit-photon interaction and hence the rate of excitation of triplet excitons because it depends on the square of the heaviest atomic number. The new exciton-spin-orbit-photon interaction operator flips the spin to a singlet form leading to faster dissociation into charge carriers and resulting in higher photon to electron-hole pair conversion efficiency in organic solar cells.
Effect of the Solvent Refractive Index on the Excited-State Lifetime of a Single Tryptophan Residue in a Protein

Excited-state lifetime and quantum yield of a fluorophore are determined by the radiative and nonradiative decay rates. There is an extensive literature about factors affecting the nonradiative decay rate. In this paper we demonstrate that the radiative decay rate for a tryptophan residue in a protein depends on the refractive index of the solvent, whether the residue is solvent-exposed or buried. We describe the theory of the refractive index effect and show that the theoretical prediction agrees with experimental data. The radiative decay rate for an electric dipole emitter embedded in a small dielectric ellipsoid of a refractive index n1 varies with the refractive index n0 of the surrounding dielectric fluid according to the law kr = γ〈ν3〉fcfn05[n02 + (n12 − n02)LM]-2, where γ is a constant factor, LM is determined by the ellipsoid axis ratio and the transition moment orientation, 〈ν3〉fcf = ∫Fλ(λ) dλ/∫λ3Fλ(λ) dλ, and Fλ(λ) represents the corrected emission spectrum. The radiative decay rate of the only.
Behaviour of Somatic and F-specific Coliphages in Slow Sand Filter

Behaviour of somatic and F-specific coliphages, as model viruses, in a full-scale slow sand filtration (SSF) treatment plant of Japan was investigated through enumeration with the conventional plaque-forming unit (PFU) and the real-time reverse transcription polymerase chain reaction (RRT-PCR). The results showed that in the effluent of SSF, concentration of coliphages decreased while Qβ phage, as a part of F-specific coliphages, was still detected by the RRT-PCR method. The detection of Qβ may indicate that F-specific RNA phages in the water were mainly derived from human faeces. Moreover, the practice of partial regeneration of the filters did not obviously affect the whole performance of the sand filters in removing coliphages and indicator bacteria (E.coli, total coliforms, general bacteria and heterotrophic bacteria). Furthermore, strong correlations were not obtained among all model viruses and indicator bacteria in the SSF effluent as well as the general water quality indices (turbidity, DOC and UV260). However, a relatively strong correlation was found existent between the indicator bacteria and particle numbers.
Étude par microscopie acoustique de couches minces de Ag2S déposées par spray

Des couches minces de sulfure d'argent Ag 2 S sont preparees sur substrat de pyrex, a la temperature de 250°C, par la technique de pulverisation chimique reactive en phase liquide ou spray'. Ces depots, d'epaisseur variable (0,4-2 μm), sont analyses par microscopie acoustique et, plus particulierement, par la methode de releve de la signature acoustique V(z). Cette signature, effectuee a differentes frequences (50, 130, 570 MHz), a permis de caracteriser les proprietes elastiques du materiau Ag 2 S. La valeur du module d'Young, de l'ordre de 180 GPa, est en accord avec la faible cohesion de la liaison Ag-S et le caractere de conducteur ionique rapide de Ag 2 S. Les observations par MEB et AFM permettent d'expliquer l'allure des courbes V(z) par les defauts de compacite lies a la methode de preparation. Les resultats experimentaux sont discutes en liaison avec la courbe de dispersion de vitesses du premier mode du systeme Ag 2 S/pyrex.
The drift-diffusion interpretation of the electron current within the organic semiconductor characterized by the bulk single energy trap level

The closed solution for the internal electric field and the total charge density derived in the drift-diffusion approximation for the model of a single layer organic semiconductor structure characterized by the bulk shallow single trap-charge energy level is presented. The solutions for two examples of electric field boundary conditions are tested on room temperature current density-voltage data of the electron conducting aluminum/tris(8-hydroxyquinoline aluminum/calcium structure [W. Brutting et al., Synth. Met. 122, 99 (2001)] for which jexp∝Va3.4, within the interval of bias 0.4 V≤Va≤7. In each case investigated the apparent electron mobility determined at given bias is distributed within a given, finite interval of values. The bias dependence of the logarithm of their lower limit, i.e., their minimum values, is found to be in each case, to a good approximation, proportional to the square root of the applied electric field. On account of the bias dependence as incorporated in the minimum value of the a.
Determination of chemical‐shift tensor orientations in methylene groups by separated‐local‐field NMR

The 13C chemical‐shift tensor orientations in the OCH2CH2O moieties of poly(ethylene oxide) (PEO) and poly(ethylene terephthalate) (PET) were determined by means of 1H13C separated‐local‐field NMR spectroscopy, and the literature values for the shift tensors in polyethylene (PE) and polyoxymethylene (POM) were improved. An angular resolution of ± 4° was attained on standard equipment with 90° pulse lengths exceeding 4 μs. Relatively high uniformity of the methylene tensor orientations, complying with local molecular symmetry, was found.
The Equilibrium Network: A New Approach for Simulation and Visualization of Aqueous Electrolyte Systems

A new simulation method for investigating mixed aqueous electrolyte systems at thermodynamic equilibrium is presented. Based on the commercial simulation package IPSEpro, a graphical procedure for assembling equilibrium systems followed by simultaneous solution of the underlying equation system was developed. At graphical setup, species and reactions objects are connected by the information of activity and stoichiometry in a network-like manner. Consequently, the resulting equations of mass action, the electro-neutrality and balance conditions are solved incorporating the Pitzer activity coefficient model and equilibrium constants from thermodynamic standard data. The method developed allows fast and flexible application of the complex thermodynamic principles to engineering tasks. The modeling approach and all basic models for graphical input and simultaneous solution of coupled equilibrium conditions are explained. For demonstration of the simulation method, example simulations for the systems of H2SO4-H2O, CaSO4-H2SO4-H2O and NaCl-CaSO4-CO2-H2O are described and evaluated successfully.
Reactions of Amines with Zwitterionic Quinoneimines: Synthesis of New Anionic and Zwitterionic Quinonoids

Following the discovery of an unprecedented transamination reaction between primary alkylamines and a quinonoid molecule of the type [C6H2([pb2]NHCH2R)2([pb2]O)2] (1), obtained from commercially available diaminoresorcinol·2HCl, we have extended this method to the use of primary arylamines, and found that, in contrast, secondary amines led to a different outcome. Whereas functionalized molecules of type 1, which are best described as 6π + 6π zwitterions, were obtained with aniline or 4-methoxyaniline, no transmination was observed with tBuNH2 in ethanol. In water, however, a reaction took place, but it afforded instead salt 6a, which resulted from hydrolysis of the imine group and deprotonation. Under similar conditions, secondary amines led to comparable results. The cations associated with the anionic quinonoid are readily exchanged in the presence of a primary amine. Whereas for the transamination reaction basic amines react under mild conditions, slightly harsher conditions are needed for less basic amines such as piperidine, diisopropylamine, or diethylamine. Transamination reactions were also performed with bis(methylamino) quinoneimine 4c, which is more soluble in organic solvents than 3. This led to the first examples of quinonoidal zwitterions functionalized with different alkyl groups on the nitrogen atoms. A number of compounds were characterized by X-ray diffraction, which allowed a better understanding of their electronic situation, and in many cases, the presence of multiple hydrogen-bond donors and acceptors results in crystal packings dominated by these interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Cumulative Disadvantage, Poverty, And The Role Of Community Capitals: A Spatial Analysis Of Uneven Development In The Multi-State Delta Region

ii DEDICATION . iii ACKNOWLEDGEMENTS . iv LIST OF TABLES . vi LIST OF FIGURES . viii CHAPTER I: INTRODUCTION . 1 CHAPTER II: LITERATURE REVIEW . 4 CHAPTER III: METHODS . 23 CHAPTER IV: FINDINGS . 32 CHAPTER V: DISCUSSION . 59 CHAPTER VI: CONCLUSION . 76 LIST OF REFERENCES . 78 APPENDICES . 87 VITA . 108
Substrate influence on infrared absorption by clusters of small spheres

In this work we study the effects of a semi-infinite substrate on the electromagnetic properties of a cluster of small spheres in the electrostatic approximation. General expressions for coefficients of the multipole expansion of the electrostatic potential of a sphere accounting for interaction between ambient particles and the substrate are obtained. Expressions for the polarizability tensor and resonant frequencies of a single sphere above a substrate are derived for the case of Lorentzian permittivities of both the sphere and substrate. Optical properties of small spheres are shown to be anisotropic due to the substrate influence.
Versatile, Benzimidazole/Amine‐Based Ambipolar Compounds for Electroluminescent Applications: Single‐Layer, Blue, Fluorescent OLEDs, Hosts for Single‐Layer, Phosphorescent OLEDs

A series of compounds containing arylamine and 1,2‐diphenyl‐1H‐benz[d]imidazole moieties are developed as ambipolar, blue‐emitting materials with tunable blue‐emitting wavelengths, tunable ambipolar carrier‐transport properties and tunable triplet energy gaps. These compounds possess several novel properties: (1) they emit in the blue region with high quantum yields; (2) they have high morphological stability and thermal stability; (3) they are capable of ambipolar carrier transport; (4) they possess tunable triplet energy gaps, suitable as hosts for yellow‐orange to green phosphors. The electron and hole mobilities of these compounds lie in the range of 0.68–144 × 10−6 and 0.34–147 × 10−6 cm2 V−1 s−1, respectively. High‐performance, single‐layer, blue‐emitting, fluorescent organic light‐emitting diodes (OLEDs) are achieved with these ambipolar materials. High‐performance, single‐layer, phosphorescent OLEDs with yellow‐orange to green emission are also been demonstrated using these ambipolar materials, which have different triplet energy gaps as the host for yellow‐orange‐emitting to green‐emitting iridium complexes. When these ambipolar, blue‐emitting materials are lightly doped with a yellow‐orange‐emitting iridium complex, white organic light‐emitting diodes (WOLEDs) can be achieved, as well by the use of the incomplete energy transfer between the host and the dopant.
Multiple‐quantum NMR spectroscopy of S=3/2 spins in isotropic phase: A new probe for multiexponential relaxation

In nuclear magnetic resonance of quadrupolar spins with S≥3/2, it is shown that excitation and observation of multiple‐quantum coherence is possible in the absence of scalar, dipolar, or quadrupolar splittings, in contrast to the widely accepted view that nonvanishing couplings are a prerequisite for the creation of multiple‐quantum coherence. In the absence of splittings, multiple‐quantum coherence can be excited because the longitudinal (‘‘T1’’) or transverse (‘‘T2’’) relaxation is multiexponential, which occurs if the motional correlation times τc are comparable to or larger than the inverse of the Larmor frequency (violation of the extreme narrowing approximation). Two experiments are described, which combine multiple‐quantum filtration with conventional spin‐echo and inversion‐recovery sequences. For isotropic motion each experiment allows one to determine the motional correlation time without knowledge of the magnitude of the quadrupolar coupling constant.
INFLUENCE OF ORGANIC MATERIALS ON THE DETERMINATION OF THE SPECTFIC SURFACE AREAS OF SOILS

Summary The surface areas of a number of soils have been determined before and after removal of organic matter by treatment with hydrogen peroxide. The external area as determined by low-temperature nitrogen adsorption increased after peroxidation. The total area derived from the nitrogen area and cetyl pyridinium bromide (CPB) adsorption generally decreased. Part of the clay-organic complex was separated from some soils, and the external and total surface areas of this material before and after peroxidation determined similarly. Both the external and total areas increased after peroxidation. These results indicate that soils contain organic materials which are not part of the clay-organic complex and which adsorb large amounts of CPB on surfaces not accessible to nitrogen molecules. A sample of peat showed a correspondingly high CPB adsorption and low nitrogen area. The large differences that occur in the nitrogen and CPB areas after peroxidation show the importance of removal of organic matter prior to the determination of the surface areas of soil clays. The surface areas were only slightly greater when carbon was completely removed by 30 per cent peroxide than when it was partly removed by 6 per cent peroxide. Organic compounds associated with the clay in the clay-organic complex are apparently able to prevent access of nitrogen molecules to many of the clay surfaces, and also probably exclude CPB from some of these surfaces.
The effect of water content on proton transport in polymer electrolyte membranes

We investigate proton transport in a polymer electrolyte membrane using continuum theory and molecular dynamics (MD) computer simulations. Specifically our goal is to understand the possible molecular origin of the effect of water content on the activation energy (AE) and pre‐exponential factor of proton conductivity, in comparison with experimental observations reported for Nafion, where a decrease of AE with increasing water content has been observed. We study proton diffusion in a single pore, using a slab‐like model. We find that although the average proton diffusion coefficient is several times smaller in a narrow pore than in a wide water‐rich pore, its AE is almost unaffected by the pore width. This contradicts an earlier proposed conjecture that the sizable Coulomb potential energy barriers near the lattice of immobile point‐like SO3– groups increase the AE in a narrow pore. Here we show that these barriers become smeared out by thermal motion of SO3– groups and by the spatial charge distribution over their atoms. This effect strongly diminishes the variation of the AE with pore width, which is also found in MD simulations. The pre‐exponential factor for the diffusion process, however, decreases, indicating a limited number of pathways for proton transfer and the freezing out of degrees of freedom that contribute to the effective frequency of transfer. Decreasing the pore size diminishes bulk‐like water regions in the pore, with only less mobile surface water molecules remaining. This hampers proton transfer. The increase of AE takes place only if the thermal motion of the SO3– head groups freezes out simultaneously with decreasing water content, but the effect is not profound. The stronger effect observed experimentally may thus be associated with some other rate‐determining consecutive process, concerned with polymer dynamics, such as opening and closing of connections (bridges) between aqueous domains in the membrane under low water content.