Miracle-dz/UniFAR-FTUs huggingface dataset:
Exergetic evaluation and comparison of quintuple effect evaporation units in Indian sugar industries

Present work analyzes and compares two quintuple effect evaporation units with and without heat recovery devices being employed. It is based on actual operational data of sugar plant. This study is primarily based on exergy analysis. Case A is a quintuple effect evaporation unit without heat recovery devices, while case B is with heat recovery devices. The average exergy efficiency is found to be 70.53% for case A, while it is 86.71% for case B. Highest exergy destruction for case A is in second effect with a value of 1562.20 kW, and for case B, it is for the first effect with a value of 1871.68 kW. Steam economy for case A is 1.99, while for case B, it is 3.46. This is due to high evaporation rates and heat recovery devices being employed for case B. The fifth effect evaporator in case A and first effect evaporator in case B are found to be the least efficient components from exergy point of view. As energy economy is concerned in terms of exhaust steam demand, case B is more attractive than case A. However, in terms of exergy, case B is less sustainable than case A. A parametric study indicated that increase in the exhaust/inlet steam temperature is highly disadvantageous in terms of exergy and quality of the end product. The authors expect that the exergy analyses results would facilitate the designers and professional practioners in the field of sugar engineering in furthering the goal of improving energy systems. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular electrochemistry and electrocatalysis: a dynamic view

The frequent simple gross redox reaction notation, where A is a solution species and Bads is its adsorbed reduction product, is misleading in its simplicity. It may represent a concerted reaction, i.e., a true elementary step in which the electron transfer (ET) to the solution species A is concerted with the creation of the electrode-species bond(s) in Bads. Conversely, the reaction may be a composite one involving two sequential steps. One such two-step mechanism may be termed as a CadsEads sequence where Cads stands for a pre-adsorption elementary step and Eads for the follow-up ET. Alternatively, the two steps may proceed in the reverse order, leading to an EsolnCads mechanism in which A is reduced into B, both being solution species, followed by adsorption of B onto the electrode. The present theoretical investigations show that a different panel of voltammetric behaviours may be produced by each mechanism. Hence, rationalising voltammetric peak positions and shapes in terms of surface or potential effects is challenging and may be completely erroneous if the wrong mechanistic sequence is considered.
Vibrational and Electronic Spectral Study on 3,5-Dihydro-4H-Imidazol-4-One Derivatives Containing Organo-Selenium

ABSTRACT The Fourier transform infrared, Raman, and UV-visible absorption spectral analyses were carried out on five 3,5-dihydro-4H-imidazol-4-one derivatives containing organo-selenium. The ground-state geometries, vibrational wavenumbers, and infrared and Raman intensities were calculated by density functional theory using the B3PW91 functional and 6-311G(2df,p) basis set. Spectral analysis shows that the large conjugation effect makes the C=N stretching vibration of the skeleton shift by 50–100 cm−1 toward the lower wavenumber. The UV-visible absorption spectra were studied by the time-dependent density functional theory method with the polarizable continuum model using B3LYP and PBE0 functionals. Theoretical calculations reveal that the strong absorption bands at 368–411 nm arise from the n → π* transition, and the sharp bands at 208–211 nm arise from the π → π* transition.
Carbon spheres for energy applications: Raman and X‐ray photoemission spectroscopy studies

The effect of nitrogen functionalization on the atomic structure of carbon spheres (CSs) with diameters ~55–900 nm, made via direct pyrolysis process, has been studied. The CSs and NCSs were made in a tubular quartz reactor placed either in a vertical furnace or in a horizontal furnace. The chemical bonding in the CSs and NCSs was investigated by means of X‐ray photoelectron (XPS) and Raman spectroscopies. XPS studies revealed a decrease in the sp3 bonded carbon sites and an associated increase in the N–sp2C bonding sites after nitrogenation. These results were further confirmed by Raman spectroscopy that showed that the ID/IG ratio increased after N addition to the spheres, indicating a rise in either the number or size of the sp2 clusters. In addition, scanning electron microscopy showed that the spheres, which are >90 at% carbon, consist of concentric graphitic shells. The possible use of CSs in magnetic data storage devices, oxygen reduction reactions, electric double layer capacitors and dye‐sensitized solar cells to generate clean and sustainable energy technologies is described. Copyright © 2013 John Wiley & Sons, Ltd.
Direct identification of yessotoxin in shellfish by liquid chromatography coupled with mass spectrometry and tandem mass spectrometry

A new method for the direct identification of yessotoxin (YTX), a polyether compound belonging to the diarrhoeic shellfish poisoning (DSP) toxins, using liquid chromatography coupled with mass spectrometry and tandem mass spectrometry (LC/MS and LC/MS/MS) is reported. Full-scan ionspray mass spectra of YTX, as acquired in single MS negative ion mode by flow injection analysis (FIA), showed the most intense ion at m/z 1141, assigned to the [M−2Na+H]−, the ion at m/z 1163, assigned to the [M−Na]− and a signal at m/z 1185, due to the deprotonated molecule [M−H]− of the analyte taken here to be the disodium salt. Collision induced dissociation of the precursor ion at m/z 1141, as obtained by FIA negative tandem mass spectrometry experiments, showed the most intense fragment ions in the higher mass region, at m/z 1061, m/z 924, m/z 855, m/z 713, which are characteristic of the structure of the analyte. Ionspray reversed phase LC/MS and LC/MS/MS was performed by isocratic elution at 30 μL/min, with a mobile phase of acetonitrile–ammonium acetate 4 mM, 80:20 (v/v), using a 1.0 mm i.d. C18 column. The detection of YTX in Italian shellfish samples collected in 1997 from the Adriatic sea was successfully carried out using this method, permitting demonstration of a false negative result obtained by the official mouse bioassay during routine control monitoring. © 1998 John Wiley & Sons, Ltd.
Radiation degradation of microcrystalline cellulose in solid status

Pulverization and degradation are important pretreatment procedures in producing bio-ethanol from cellulose. In this study, microcrystalline cellulose (MCC), a pure α-cellulose, was degraded by γ-irradiation. The average degree of polymerization, content of reducing sugar, crystalline structure, and molecular structure were investigated to elucidate the radiation effect on the degradation of MCC. The results manifested that γ-ray destroyed part of the chemical bond and hydrogen bond, leading to the degradation of cellulose and increasing of the reducing sugar content. According to the Fourier transform infrared result, radiation degradation led to the formation of reductive carbonyl group. Meanwhile, radiation had slight influence on the crystalline structures of MCC. Therefore, the radiation degradation procedure is expected to benefit the further proceedings such as ultrafine treatment and enzyme hydrolysis of cellulose. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Interactions of H2O molecules in ice I. The dipole moment of an H2O molecule in ice

The dipole moment of an H2O molecule in ice is greater than the moment of an isolated H2O molecule, 1·84 D, owing to the electric fields of neighbouring molecules. The magnitude and direction of the field arising from the nearest 85 neighbours is computed here by representing each molecule as a series of electric multipoles. It is found that the field has the direction of the dipole moment of the central molecule and is sufficiently strong to increase its total dipole moment to about 2·60 D.
Charge and Mass Transfer Across the Metal/Solution Interface

Electrode reactions are characterized by charge transfer across the interface. The charge can be carried by electrons or by ions. It is shown here that when both mass and charge cross the interface, the charge must be carried by the ionic species, not by the electrons, as a result of the very large difference in the time scale for electron and ion transfer. A prime example of charge transfer by ions is metal deposition. It is proposed that ion transfer occurs by migration of the ions across the interface, under the influence of the high electrostatic field in the double layer. The rate constants observed for metal deposition are comparable to those for outer-sphere charge transfer. These unexpectedly high rate constants for metal deposition are explained by a model in which removal of the solvation shell and reduction of the effective charge on the metal ion occur in many small steps, and a make-before-break mechanism exists, which lowers the total Gibbs energy of the system as it moves along the reaction coordinate from the initial to the final state.
Syntheses and Carbonyliridium Complexes of Unsymmetrically Substituted Fluorous Trialkylphosphanes: Precision Tuning of Electronic Properties, Including Insulation of the Perfluoroalkyl Groups

Reactions of iodides I(CH2)mRf8 [m = 2−4; Rf8 = (CF2)7CF3] and LiPH2 · DME (−45 °C, THF) give the primary phosphanes PH2(CH2)mRf8 (7−9; 48−76%). Radical-initiated reactions (100 °C) of 7 and H2C=CHCH2Rf8, 8 and H2C=CHRf8 or H2C=CHCH2CH2Rf8, and 9 and H2C=CHCH2Rf8, give the title phosphanes P[(CH2)mRf8]2[(CH2)m′Rf8] [m/m′ = 2/3 (10), 3/2 (11), 3/4 (12), 4/3 (13); 70−76%]. The symmetrically substituted phosphane P[(CH2)mRf8]3 (m = 5, 6) is similarly prepared from PH3 and H2C=CHCH2CH2CH2Rf8, analogously to previously reported homologs [m = 2 (2), 3 (4), 4 (5)]. Reactions of 10−13 and 2, 4, 5, and 6 with [Ir(COD)Cl]2 and CO give trans-Ir(CO)(Cl)(PR2R′)2 (70−83%). The IR νCO values show a monotonic decrease with increasing numbers of CH2 groups. Phosphanes 13, 5, and 6 have the most CH2 groups, and give νCO values 10, 7, and 4 cm−1 higher than the unfluorinated phosphane P[(CH2)7CH3]3. Hence, 6 provides nearly complete insulation of the iridium center from the electronegative perfluoroalkyl groups. Analogous rhodium derivatives of 4 and 5 are also described.
Self‐assembling in a living supramolecular linear nematic polymer‐like system

Self‐assembling in a linear supramolecular liquid crystalline (LC) polymer based on 4,4′‐bipyridine and bis‐(4‐carboxyphenyloxycarbonyl)‐heptanoate was studied by IR spectroscopy and optical microscopy. Although just a simple single hydrogen bond is required for the formation of a polymer chain, the reversibility of the hydrogen bonding forces the supramolecular macromolecule to behave under specific conditions similar to a mixture composed of two partly immiscible low molecular weight materials rather than as a polymer. An analytical description indicates that nematic droplets form two overlapping thermodynamically optimised statistical ensembles all across the phase transition in the linear supramolecular LC polymer studied. The kinetics of the nematic nucleus growth in the melted polymer was also studied. The number of generated nematic droplets oscillates with time. Two regimes of the growth kinetics were recognised: (i) nucleation and nucleus growth and (ii) nucleus coarsening, i.e. Ostwald ripening.
Determination of sulfite and thiosulfate in aqueous samples including anoxic seawater by liquid chromatography after derivatization with 2,2'-dithiobis(5-nitropyridine)

Dosage par chromatographie HPLC avec detection UV. Utilisation d'un agent de paire d'ions, le sulfate de tetrabutyl-ammonium, pour optimiser la separation sur une microcolonne en phase inverse (C18). Application de la methode a l'analyse d'echantillon d'eau de la Mer Noire
Synthesis of Polycyclic Alkaloid-Type Compounds by an N-Acyliminium Pictet―Spengler/Diels―Alder Sequence

A range of structurally diverse penta- and hexacyclic alkaloid-type compounds have been prepared in a two-step procedure from readily available starting materials. A flexible N-acyliminium Pictet-Spengler reaction employing electron-rich -arylethyl-amines, cinnamaldehyde derivatives, and alkynoyl chlorides sets the stage for an intramolecular Diels-Alder cycloaddition. The complex and diverse polycyclic alkaloid-like compounds are easily obtained in reasonable to excellent yield in a reliable and efficient reaction sequence. © Georg Thieme Verlag Stuttgart New York.
An application of the self-consistent variational effective potential against the path-integral to compute equilibrium properties of quantum simple fluids

The thermodynamic and structural features obtained from the self-consistent variational effective potential SCP (developed by Feynman and Kleinert and by Giachetti and Tognetti) in the study of quantum fluids are analysed, taking the full path-integral (PI) treatment as a reference and helium-4 as a probe. Within the SCP method the pair radial distribution functions are of two types: one describing the correlations between the centroids of the quantum particles, and the other describing the true correlations between quantum particles. An analytical derivation states that the SCP picture for quantum particles does not distinguish between the instantaneous and the linear response pair radial distribution functions, which otherwise can be defined within a full path-integral framework by considering equal imaginary time or mixed imaginary time averages, respectively. It is also shown how the centroid and true quantum particle pair radial distribution functions are connected through a convolution. Explicit for.
Application of Elimination Voltammetry to the Resolution of Adenine and Cytosine Signals in Oligonucleotides. I. Homo-oligodeoxynucleotides dA9 and dC9

Elimination voltammetry with linear scan (EVLS) has been applied to the resolution of reduction signals of adenine and cytosine in short synthetic homo-oligodeoxynucleotides (dA9 and dC9). In comparison with the common electrochemical methods (linear sweep, differential pulse, and square wave voltammetry) EVLS enables to resolve the overlapped signals by using the function which eliminates the charging and kinetic currents ( , ) and conserves the diffusion current ( ). For the adsorbed electroactive substance, this elimination function gives a well readable peak-counterpeak which has successfully been utilized to the analysis of overlapped reduction signals of adenine and cytosine on hanging mercury drop electrode (HMDE). The height and potential of signals studied were affected by the dC9/dA9 ratio, the time of accumulation, the stirring speed during the adsorption, and pH. Our results showed that EVLS in connection with the adsorption procedure is a useful tool for qualitative and quantitative studies of short oligonucleotides.
Characterisation of the (H3-H4)2-tetramer and its interaction with histone chaperones

Histones are a major protein component of chromatin, yet mechanisms which control synthesis, post translational modification, deposition and removal of histones are not fully understood. Although atomic resolution structures have been solved for the nucleosome core particle, there is limited information regarding the conformation of the core histones outside of chromatin. Insight into the structure of soluble histones, and the complexes they form, is likely to further our understanding of important nuclear processes such as transcription, chromatin replication and epigenetic inheritance. In this study we employ novel biochemical and biophysical techniques to address two key questions in the field: the structure of the soluble (H3-H4)2-tetramer, and the conformation of H3 and H4 in complex with histone chaperones. Firstly, we determined the conformation of histones H3 and H4 when in complex with two histone chaperones from S. cerevisaie, Nap1 and Vps75. Within the nucleosome H3 and H4 form a heterotetrameric structure sustained by the interface between two histone H3 proteins. Interestingly, when bound to the histone chaperone Asf1 the H3-H3’ interaction is disrupted, thus Asf1 effectively splits the tetramer binding a single H3-H4 dimer. Using targeted protein crosslinking and pulsed EPR we determine that, unlike Asf1, the Nap1 family of histone chaperones can bind H3-H4 in their tetrameric conformation, analogous to that observed within the nucleosome. The ability to bind H3 and H4 as a tetramer has implications in the prevalence of chromatin states during DNA replication and transcription, and may be in part responsible for the alternate in vivo functions of these two classes of chaperones. Secondly, using site direct spin labelling in conjunction with pulsed EPR we probe in detail the structure of the soluble (H3-H4)2-tetramer. Whilst the core crescent shape of the tetramer surrounding the H3-H3’ interface is retained, discrete regions such as the αN helix of H3 are more structurally heterogeneous than in the histone octamer or nucleosome. Such structural heterogeneity in the αN helix of H3 highlights potential roles in the post translational modification of histones and in their binding to histonechaperones. These new findings reveal possible modes of interaction between a tetramer
Quantum dots as fluorescent bio‐labels in cancer diagnostic

In this work we present and discuss some results concerning the application of colloidal semiconductor quantum dots for cancer diagnostic. We have prepared and applied different core-shell semiconductor quantum dots such as Cadmium Teluride-Cadmium Sulfide (CdTe-CdS) and Cadmium Sulfide –Cadmium Hydroxide (CdS/Cd(OH)2). For the purpose of diagnostic with living cells, the CdS/Cd(OH)2 presented best results, maintaining high levels of luminescence as well high stability in biological media. The quantum dots were obtained in aqueous medium, by reacting Cd2+ and S2– in the presence of sodium polyphosphate as the stabilizing agent. Subsequent surface passivation with Cd(OH)2 was carried out to improve luminescence. At a pH of 7,2 the quantum dots were functionalized with a 0.01% glutaraldehyde solution and then, incubated with living healthy and neoplastic cells (glial, glioblastoms and cervical) and tissues (breast) in culture medium. Tissue and cell staining were evaluated by the laser scanning confocal microscopy. Fluorescence Microscopy was used as a primary tool in order to explore the labeling of the samples. The procedure presented in this work, shown to be very efficient as a potential tool for fast and precise cancer diagnostic. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Gas diffusion through columnar laboratory sea ice: implications for mixed-layer ventilation of CO2 in the seasonal ice zone

Gas diffusion through the porous microstructure of sea ice represents a pathway for ocean.atmosphere exchange and for transport of biogenic gases produced within sea ice. We report on the experimental determination of the bulk gas diffusion coefficients, D, for oxygen (O2) and sulphur hexafluoride (SF6) through columnar sea ice under constant ice thickness conditions for ice surface temperatures between -4 and -12°C. Profiles of SF6 through the ice indicate decreasing gas concentration from the ice/water interface to the ice/air interface, with evidence for solubility partitioning between gas-filled and liquid-filled pore spaces. On average, DSF6 was 1.3 × 10-4 cm2 s-1 (±40%) and DO2 was 3.9 × 10.5 cm2 s-1 (±41%). The preferential partitioning of SF6 to the gas phase, which is the dominant diffusion pathway produced the greater rate of SF6 diffusion. Comparing these estimates of D with an existing estimate of the air.sea gas transfer through leads indicates that ventilation of the mixed layer by diffusion through sea ice may be negligible, compared to air.sea gas exchange through fractures in the ice pack, even when the fraction of open water is less than 1%.
57Fe Mössbauer Spectroscopy of Montmorillonites: A New Interpretation

The 57Fe Mössbauer spectra of several montmorillonites, measured at room temperature and 453 K, showed a considerably broadened Fe3+ resonance which can be computer-fitted with a similarly broadened Fe3+ doublet. In some spectra, particularly if all linewidths were constrained to be equal, this broadened Fe3+ resonance was further resolved into overlapping inner and outer Fe3+ doublets, also having broad linewidths. In accordance with recent electron diffraction evidence, the assignment by previous workers of the inner doublet to Fe3+ in the octahedral sites having the cis-arrangement of OH groups and the outer doublet to the octahedral site having the trans-arrangement of OH groups is incorrect. Instead, the Fe3+ was found to be located largely in the trans-octahedral sites. Because of the relatively low iron content of the montmorillonite examined, the next and more distant neighboring-cation environment varied considerably about the octahedral Fe3+ ions. This variation produced a broadened experimental resonance, and the resulting two-doublet computer fits probably represent the mean extremes of a continuum of slightly different Fe3+ resonances arising from the variable nature of the environment surrounding these such trans-sites, rather than distinct cis- and trans-sites. In addition, a small resonance indicating the substitution of Fe3+ into the tetrahedral sites was observed. The interlayer species probably influenced the Mössbauer resonance of Fe3+ in the tetrahedral and octahedral sites.
Fuel Cell Hybrids, Their Thermodynamics and Sustainable Development

The increasing demand on primary energy and the increasing concern on climatic change demand immediately a sustainable development, but still there remain open questions regarding its technical realisation. The second law of thermodynamics is a very simple but efficient way to define the principle design rules of sustainable technologies in minimising the irreversible entropy production. The ideal, but real process chain is defined by a still reversible structure or logic of the process chain—the reversible reference process chain—but consisting of real components with an irreversible entropy production on a certain level. It can easily be shown for energy conversion and for transportation that hybridisation in general can be indeed a measure to meet the reversible process chain and to minimise the entropy flow to the environment. Fuel cells are principal reversible converters of chemical energy and thus a key element within hybridisation. Depending on application, CHP may be a hybridisation step or only a slight improvement. There is a fundamental difference in heating a house or in supplying an endothermic chemical reaction with reaction entropy. The use of heat recovery and isolation is a necessary measure to minimise the entropy flow to the environment and can be described by a reversible reference process as well. The application of reversible reference process chains shows that hybrid systems with fuel cells are a technical feasibility to approach very closely the thermodynamic potential. This development differs from the past where the technical possibilities of materials and manufacturing limited the technology to meet reversibility and thus sustainability.Copyright © 2005 by ASME