Transfer Interactions Research Articles

Adsorption fixed beds modeling revisited: Generalized solutions for S-shaped isotherms

ABSTRACTAdsorption fixed bed models are of paramount importance in chemical and environmental engineering research. Although the related literature is rich, the vast majority of models employed are either phenomenological, based on chemical reaction kinetics, or limited to systems that obey simple equilibrium isotherms (favorable, unfavorable, linear, and rectangular) combined to linear driving force (LDF) for the solid-phase mass transfer kinetics and ideal plug flow. This paper complements the existing studies by presenting and analyzing a versatile nondimensional fixed bed model equipped with diffusion-based mass transfer kinetics and nonideal flow terms and adapted to deal with S-shaped (sigmoidal) isotherms. A discussion is conducted on the rather unusual fixed bed dynamics produced by systems that follow S-shaped isotherms, a subject which has been rarely and nonsystematically discussed in the related literature. Thus, this study aims at providing better understanding of the interactions of S-shaped isotherms, mass transfer, and axial dispersion on the shape of adsorption fixed bed breakthrough curves and comes to clarify and complement previously published results, especially on the unexplored effects of the isotherms’ inflection point on the breakthrough curves.

Volumetric Behavior of Sodium Saccharin in Water and (0.1, 0.3, and 0.5) m Fructose at (298.15, 303.15, 308.15, and 313.15) K

In order to get the information regarding the sweetener-water and sweetener-sweetener interactions, densities of sodium saccharin in water and (0.1, 0.3, and 0.5) m fructose have been measured at (298.15, 303.15, 308.15, and 313.15) K by the use of bicapillary pycnometer. From density values, partial molar volumes, expansion coefficient, Hepler’s constant, apparent specific volumes, partial molar volumes of transfer, doublet and triplet interaction coefficients have been calculated. From density study, it has been concluded that strong water-sodium saccharin interactions exist. Sodium saccharin is water structure maker. Strong interactions exist between sodium saccharin and fructose. In presence of fructose, the interactions exist between hydrophilic group (–OH, C=O, and –O–) of fructose and sodium ion of sodium saccharin in aqueous solutions of sodium saccharin. All investigated solutions exhibit sweet taste. DOI: http://dx.doi.org/10.17807/orbital.v9i1.921

Bridging the gap between observational oceanography and users

Abstract. In order to ensure relevance and societal impact of research and to meet the various requirements of different target groups, the Coastal Observing System for Northern and Arctic Seas (COSYNA) developed and pursued a broad range of activities for knowledge transfer and stakeholder interaction. Potential user groups of data and data products include (but are not limited to) science, administration, renewable energies, engineering, tourism, and nature conservation. COSYNA data and data products are publicly accessible and available free of charge via the Internet (data portal; www.cosyna.de). The stakeholder interaction is integrated into the COSYNA product life cycle outlined here and the steps undertaken are exemplified for the product Surface Current Fields in the German Bight. Initial surveys revealed COSYNA's potential relevance in the national and international context. After the technological and mathematical realization of high-quality parameter fields, external experts evaluated the scientific value, informational value, innovative leap, cost/benefit aspects, operability, etc., of the data products. In order to improve products and their usability and to pave the way for future co-operation, interviews and workshops with potential users from the offshore wind energy industry were conducted. The stakeholder interaction process was successful, revealing relevant insights into user demands and usability of (possible) products. Analysis of data download provided some evidence for impact beyond academia. Other criteria for the increasingly demanded evaluation of the impact of coastal research are discussed. By sharing first-hand experiences, this study contributes to the emerging knowledge on integration of science and end users.

Studies on the σ–hole bonds (halogen, chalcogen, pnicogen and carbon bonds) based on the orientation of crystal structure

ABSTRACTThe 4,7-dibromo-5,6-dinitro-2,1,3-benzothiadiazole (DDBT) crystal has two polymorphic forms [1], where the close contacts between two electronegative atoms are identified and studied through Hirshfeld surface analysis. Br---Br and O---O cut-off distances are addressed and analysed. The σ–hole of bromine, sulphur, oxygen atoms and π-hole of carbon and nitrogen atoms were subjected to study using molecular electrostatic potential map and 3D-deformation density map. Sixteen types of dimers from the two forms of crystal structure (6 for form I and 10 for form II) were studied using the charge transfer properties and interaction energies and made detailed analysis of halogen bond (Br---N), dihalogen bond (Br---Br), chalcogen bond (O---Br and S---Br), dichalcogen bond (S---O, O---S and O---O), pnicogen bond (N---O) and carbon bond (C---O and C---Br) interactions. The impact of orientations is discussed to define the type of interaction and its strength through charge transfer mechanism. The contribution of bond angle values for the σ-hole and π–hole bonds are discussed. Utilisation of σ–hole in smaller bond angle values (above 30°) of |θ1 − θ2| existing in type II halogen–halogen bond have been examined in the two forms.

Explicit inclusion of nonlocality in(d,p)transfer reactions

Background: Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation. Purpose: Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel. Method: We extend the finite-range adiabatic distorted wave approximation to include nonlocal nucleon optical potentials. We apply our method to (d,p) reactions on 16O, 40Ca, 48Ca, 126Sn, 132Sn, and 208Pb at 10, 20 and 50 MeV. Results: We find that nonlocality in the deuteron scattering state reduces the amplitude of the wave function in the nuclear interior, and shifts the wave function outward. In many cases, this has the effect of increasing the transfer cross section at the first peak of the angular distributions. This increase was most significant for heavy targets and for reactions at high energies. Conclusions: Our systematic study shows that, if only local optical potentials are used in the analysis of experimental (d,p) transfer cross sections, the extracted spectroscopic factors may be incorrect by up to 40% due to the local approximation.

The roles of boundary spanners and mentalizing skills in alliance learning and knowledge transfer

Although there is growing awareness of the significance of learning and knowledge transfer in inter-firm collaboration, most studies have been at the firm or firm-to-firm level; few have investigated individual-level effects on learning and knowledge transfer. There is thus a gap in the literature on our understanding of micro-level issues. The individuals who are responsible for the day-to-day management of inter-firm collaboration are often referred to as boundary spanners. In this paper, we emphasize boundary spanners’ actions and interactions in learning and knowledge transfer between firms, and draw on theory of mind, particularly the concept of mentalizing skills. In this paper, we develop a conceptual framework that examines the role of boundary spanners’ mentalizing skills, and posit a set of propositions that suggest how differences in mentalizing skills among boundary spanners may influence a firm’s ability to reveal the true intentions of its partner, identify the partner’s ability to absorb ne...

Interaction for transfer: flexible approaches to multilingualism and their pedagogical implications for classroom interaction in linguistically diverse mainstream classrooms

ABSTRACTThis study focuses on how teachers construe and give meaning to a pedagogical experiment in which the use of the home language in a primary school in Flanders was permitted in order to acknowledge the urban multilingual realities and resources of the pupils and to turn them into didactic capital (functional multilingual learning, FML). Using ethnographic interviews, teachers were asked to comment on recorded classroom activities in which FML played a role. Results showed that teachers created space for FML by facilitating and stimulating peer interaction, but tended to leave the interaction in the hands of the pupils. Teachers viewed individual learning outcomes as more important than collectively organized interactional efforts. Individual pupil characteristics occurred as a starting point to manage and organize classroom activities.

Synergistic and diminutive effects between halogen bond and lithium bond in complexes involving aromatic compounds.

Quantum chemical calculations have been performed to study the interplay between halogen bond and lithium bond in the ternary systems FX-C6H5CN-LiF, FLi-C6H5CN-XF, and FLi-C6H5X-NH3 (X = Cl, Br, and I) involving aromatic compounds. This effect was studied in terms of interaction energy, electron density, charge transfer, and orbital interaction. The results showed that both FX-C6H5CN-LiF and FLi-C6H5CN-XF exhibit diminutive effects with the weakening of halogen bond and lithium bond, while FLi-C6H5X-NH3 displays synergistic effects with the strengthening of halogen bond and lithium bond. The nature of halogen bond and lithium bond in the corresponding binary complexes has been unveiled by the quantum theory of atoms in molecules methodology and energy decomposition analysis.

Theoretical study of interaction of thiazolidine-2-thione as an anti-thyroid agent with iodine

Quantum chemical calculations were used to investigate the interaction of tautomer forms of thiazolidine-2-thione (T2T) with iodine in the gas and solution phases. The calculations show that the planar complexes are more stable than the perpendicular complexes. Also in the perpendicular complexes, the thione form is more stable than the thiol form. The calculated thermodynamic parameters in the solution phase indicate that the stability of the formed complexes increases as the dielectric constant of the solvent is increased. This result is in good agreement with the experimental results. The NBO results predict that the LP(S) → σ*(I─I) and LP(S) → σ*(N─H) charge transfer (CT) interactions are very important in the stabilizing of the planar complexes with respect to the perpendicular complexes. In all complexes, CT takes place from T2T to I2. Therefore, it is predicted that the donor properties of T2T are the origin of its anti-thyroid action. The atoms in molecule (AIM) analysis shows that the interactions in the planar complexes are stronger than the perpendicular complexes.

Molecular Spectroscopic Characterization and Electronic Structure Analysis of N- benzylaniline- A DFT Approach

The FT-IR and FT-Raman spectra of N-benzylaniline[NBZA] have been analysed in the region 4000-450cm-1 and 4000-50cm-1respectively. The geometrical structure, harmonic vibrational frequency, infrared intensity, Raman activities and bonding features of the title compound were carried out by DFT method with B3LYP/6-311++G(d, p) basis set. The complete vibrational frequency assignments were made by normal co-ordinate analysis following the scaled quantum mechanical force field methodology (SQM). The charge transfer and hyperconjugative interactions have been analysed using natural bond orbital (NBO) and HOMO-LUMO analysis. The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MESP). The thermodynamic properties of the title compound at the different temperatures have been calculated. The mulliken charges, the values of electric dipole moment (µ) of the molecule were computed using DFT calculations and the results are interpreted. The UV absorption spectrum of the title compound has been described at the experimental level.

A Method to Derive the Definition of Generalized Entropy from Generalized Exergy for Any State in Many-Particle Systems

The literature reports the proofs that entropy is an inherent property of any system in any state and governs thermal energy, which depends on temperature and is transferred by heat interactions. A first novelty proposed in the present study is that mechanical energy, determined by pressure and transferred by work interactions, is also characterized by the entropy property. The second novelty is that a generalized definition of entropy relating to temperature, chemical potential and pressure of many-particle systems, is established to calculate the thermal, chemical and mechanical entropy contribution due to heat, mass and work interactions. The expression of generalized entropy is derived from generalized exergy, which in turn depends on temperature, chemical potential and pressure of the system, and by the entropy-exergy relationship constituting the basis of the method adopted to analyze the available energy and its transfer interactions with a reference system which may be external or constitute a subsystem. This method is underpinned by the Second Law statement enunciated in terms of existence and uniqueness of stable equilibrium for each value of energy content of the system. The equality of chemical potential and equality of pressure are assumed, in addition to equality of temperature, to be necessary conditions for stable equilibrium.

Spectroscopic, thermal studies and molecular modelling of charge transfer complexation between 5-amino-2-methoxypyridine with chloranilic acid in different polar solvents

Charge transfer (CT) interaction between 5-amino-2-methoxypyridine (5AMPy), as electron donor (proton acceptor), with 3,6-dichloro-2,5-dihydroxy-p-benzoquinone (chloranilic acid, H2CA), as electron acceptor (proton donor), has been investigated spectrophotometrically in the polar protic solvents ethanol (EtOH) and methanol (MeOH) and the aprotic one acetonitrile (AN). Pink-coloured solution is formed instantaneously upon mixing 5AMPy with H2CA solutions in all solvents, which is the hallmark evidence of CT complex formation. Based on Job’s method of continuous variations, as well as spectrophotometric titrations, the stoichiometry of the complex was found to be 1:1 [(5AMPy) (H2CA)] in all solvents. Benesi–Hildebrand equation has been applied to estimate the formation constant of the produced CT complex (KCT) and its molar absorptivity (ε), they reached high values, confirming the complex high stability. Solid CT complex has been synthesised and analysed by elemental analyses and FTIR, 1H NMR spectroscopies, where 2:1 [(5AMPy)2 (H2CA)] CT complex was obtained.

Interplay of hole transfer and host-guest interaction in a molecular dyad and triad: ensemble and single-molecule spectroscopy and sensing applications.

A new molecular dyad consisting of a Cy5 chromophore and ferrocene (Fc) and a triad consisting of Cy5, Fc, and β-cyclodextrin (CD) are synthesized and their photophysical properties investigated at both the ensemble and single-molecule levels. Hole transfer efficiency from Cy5 to Fc in the dyad is reduced upon addition of CD. This is due to an increase in the Cy5-Fc separation (r) when the Fc is encapsulated in the macrocyclic host. On the other hand, the triad adopts either a Fc-CD inclusion complex conformation in which hole transfer quenching of the Cy5 by Fc is minimal or a quasi-static conformation with short r and rapid charge transfer. Single-molecule fluorescence measurements reveal that r is lengthened when the triad molecules are deposited on a glass substrate. By combining intramolecular charge transfer and competitive supramolecular interaction, the triad acts as an efficient chemical sensor to detect different bioactive analytes such as amantadine hydrochloride and sodium lithocholate in aqueous solution and synthetic urine.

Pleated Surface Morphology of C60 Fullerene Nanowhiskers Incorporated by Polyaniline in N-Methyl-2-Pyrrolidone

The addition of polyaniline emeraldine base dissolved in N-methyl-2-pyrrolidone (PAni/NMP) on fullerene C60 whiskers (FW) by direct-mixing technique resulted to the formation of a hybrid material herein called FW/PAni hybrid. The FW/PAni hybrid has a tubular structure with pleated surface texture. It is thinly coated with PAni and has a higher surface area relative to pristine FW and PAni. Beneath the amorphous outer covering, the hybrid shows a crystalline structure as shown by high resolution TEM and selected area electron diffraction. Charge transfer (CT) interaction from electron-rich PAni to electron deficient FW may have resulted to the physical chain entanglement of PAni to FW. The tubular structure of the hybrid is likely caused by the lone pair electrons present in both NMP and PAni causing dissolution inside the whisker. The FW/PAni hybrid having a large surface area and narrow pore size distribution has potential use as hydrogen adsorbent for fuel cell applications, catalysts, and templates for nanofabrication.

Photoinduced intramolecular electron transfer and electronic coupling interactions in π- expanded imidazole derivatives.

An intramolecular excited charge transfer (CT) analysis of imidazole derivatives has been made. The determined electronic transition dipole moments has been used to estimate the electronic coupling interactions between the excited charge transfer singlet state ((1)CT) and the ground state (S0) or the locally excited state ((1)LE). The properties of excited (1)CT state imidazole derivatives have been exploited by the significant contribution of the electronic coupling interactions. The excited state intramolecular proton transfer (ESIPT) analysis has also been discussed.

The role of exchange interaction in nonradiative energy transfer between semiconductor quantum dots

The contribution of exchange interaction to the probability of nonradiative energy transfer between two (donor and acceptor) semiconductor quantum dots based on A3B5 compounds has been analyzed using the Kane model of energy-band structure. It is established that the dependence of the exchange contribution on the distance between donor and acceptor centers has a power character for nearly contact distances and acquires an exponential character when the distance increases. Numerical calculations showed that the exchange contribution is comparable with that of the dipole-quadrupole interaction of quantum dots and is one to two orders of magnitude lower than the contribution of the dipole-dipole interaction at shorter distances.

Special Section on Interconnection of Atmospheric Water, Surface Water, and Groundwater

As the climate changes, conjunctive use and management of water resources, or integrated water resources management, has become critically important for water resource planners and managers. Climate variability has resulted in irregular precipitation and temperature patterns, and, in turn, extreme storm events causing floods and frequent droughts. Such extreme events have raised stakeholders’ concerns for water availability. Conjunctive uses of multiple water resources are best management practices/ strategies to address this change in water availability. To implement such strategies, an important aspect gaining a better understanding of the hydrological interconnections among atmospheric water, surface water, and groundwater (three waters) as well as their trends or patterns with climate variations. The Earth’s hydrologic cycle is defined as “the pathway of water as it moves in its various phase through the atmosphere, to the Earth, over and through the land, to the ocean, and back to the atmosphere” (National Research Council 1991). Water in this hydrologic cycle (Chow et al. 1988) may be divided into atmospheric water, surface water, and groundwater (subsurface water). Surface water and atmospheric water transfer to each other through water surface evaporation, evapotranspiration by aquatic plants, and precipitation; groundwater and atmospheric water transfer to each other through near-surface evaporation, evapotranspiration through plants, and deep percolation of precipitation. Surface water and groundwater transfer to each other through seepage when they are hydraulically connected or by infiltration when they are hydraulically disconnected. This three-water transfer has been recognized since the latter part of the seventeenth century (Todd and Mays 2005). The three-water interactions mainly occur on the water’s surface, the land’s surface, and in the vadose zone above the groundwater table, as well as in the hyporheic zone between surface water and groundwater. Along with this water transfer, bio-chemical, physical, and kinetic interactions occur between atmospheric water, surface water, and groundwater. The threewater interactions involve multiple disciplines such as meteorology, surface hydrology, subsurface hydrology, geology, agronomy, pedology, and bio-ecology, to name just a few. Significant advances in understanding three-water interactions have been made over the last several decades. For example, advances in interactions between groundwater and surface water have been overviewed (Winter 1995, 1999; Sophocleous 2002; Diiwu 2003) since the growth in research related to surface-subsurface exchange processes mushroomed during the 1990s (Stanley and Jones 2000). Winter (1995) reviewed advances in understanding the interaction of groundwater and surface water in different landscapes: mountain, riverine, coastal, hummocky, and karst terrains. Winter (1999) proposed three general theoretical considerations regarding the interaction of groundwater with surface water. This interaction is affected by (1) different-scale groundwater flow systems, (2) local soil and geologic controls on seepage distribution, and (3) the magnitude of transpiration directly from groundwater around a surface-water perimeter since this transpiration intercepts potential groundwater inflows or draws water from surface-water bodies. Sophocleous (2002) synthesized and exemplified the interactions between groundwater and surface water in relation to climate, landform, geology, and biotic factors. Diiwu (2003) reviewed fundamental concepts of the ecohydrology of the interaction between groundwater and surface water, and discussed the relevance of this interaction to the sustainable management of water resources in semi-arid regions. A task committee (see subsequent information) was established within the Groundwater Council to promote scientific exchange and share experiences by inviting scientists and researchers to prepare articles and presentations focusing on the state of science relative to the interaction of atmospheric water, surface water, and groundwater, and on the impacts of climate change on water resources, as well as their conjunctive management and uses. This special section includes a collection of invited and peer-reviewed papers including field investigations, numerical simulations, and practical case studies on the following topics: physical/hydrological characterization of interactions; analytical and numerical models for simulating interactions; conjunctive uses and management of the three waters; climate change impacts on interaction of the three waters, including extreme events such as floods and drought; and water quality issues related to such interactions. In this special section, authors present their recent research findings on the interactions of the three waters and their associated processes. It is anticipated that this collection will promote further scientific exchange and further advances of our knowledge in this research area. We are very appreciative of the authors’ contribution and efforts and of the constructive comments and timely reports by reviewers and editors.

Modeling triplet flavin-indole electron transfer and interradical dipolar interaction: a perturbative approach

A benchmark biochemical reaction is here theoretically investigated by means of a perturbative approach in order to model each reaction step. The reaction is the flavin-indole electron transfer, involving also a spin-state relaxation of the ionic complex. The whole reaction path is modeled and the kinetics of the process is studied. The dipolar interaction between the two radicals is explicitly considered during the dynamic evolution of the system in order to investigate the proper conditions for the triplet-to-singlet transition to occur.

Interaction of atenolol with iodine: a novel structural formula of charge transfer complexes

Interaction of atenolol (ATE), as an electron donor, with iodine (I2), as a typical σ-electron acceptor, has been studied. This interaction occurs in several remarkable steps. The first step is the initial formation of the ATE–I2 outer charge transfer (CT) complex, meanwhile this interaction ends with the formation of the solid CT complex which has the stoichiometric ratio 4:2 (ATE:I2). The synthesized solid CT complex has a novel and amazing structural formula in which hydrogen bonds exist side by side with the CT binding. Formation constants, molar absorption coefficients, and thermodynamic properties, ΔH, ΔS, and ΔG, of this ATE/I2 interaction have been determined and discussed. The different structural forms of the ATE/I2 complexes which occur in each of the different formation steps, involving their stoichiometric ratios, have been determined and confirmed. Several techniques involving UV/Visible, FT-IR, 1H NMR, and Mass spectra have been used in this study. In addition, morphology of the synthesized solid complex has been investigated by the scanning electron microscope. The charge transfer (CT) interaction between atenolol (ATE) and iodine (I2) occurs in several remarkable steps starting with an initial formation of the ATE–I2 outer CT complex and ending by formation of the solid CT complex having the stoichiometric ratio 4:2 (ATE:I2). The synthesized solid CT complex has a novel and amazing structural formula in which hydrogen bonds exist side by side with the CT binding. Several techniques involving UV/Visible, FT-IR, 1H NMR, and Mass spectra have been used in this study. In addition, morphology of the synthesized solid complex has been investigated by the scanning electron microscope (SEM).

CFD Study on Wall/Nanoparticle Interaction in Nanofluids Convective Heat Transfer

The Brownian motion of the nanoparticles in nanofluid is one of the potential contributors to enhance effective thermal conductivity and the mechanisms that might contribute to this enhancement are the subject of considerable discussion and debate. In this paper, the mixing effect of the base fluid in the immediate vicinity of the nanoparticles caused by the Brownian motion was analyzed, modeled, and compared with existing experimental data available in the literature. CFD was developed to study the effect of wall/nanoparticle interaction on forced convective heat transfer in a tube under constant wall temperature condition. The results showed that the motion of the particle near the wall which can decrease boundary layer and the hydrodynamics effects associated with the Brownian motion have a significant effect on the convection heat transfer of nanofluid.