Terms Of Packing Research Articles

N-acetyl-5-isopropyl-2-tioxoimidazolidin-4-one: Synthesis, spectroscopic characterization, crystal structure, DFT calculations, Hirshfeld surface analysis and energy framework study

Studies based on the role of non-covalent interactions in supramolecular structure of materials with pharmacological properties have gained considerable relevance. Herein, we report the structural characterization of a new thiohydantoin compound which are important heterocyclic scaffolds and a class of well-known molecules for their pharmacological properties. N-acetyl-5-isopropyl-2-thioxoimidazolidin-4-one compound has been synthesized and characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Its crystal structure was also determined by single-crystal X-ray diffraction studies. This material crystallizes in the triclinic system with space group P1¯(N°2), Z = 4, with two independent molecules in the asymmetric unit. The crystal packing is governed by N–H⋯O hydrogen bond-type intermolecular interactions, forming infinite one-dimensional chains with graph-set motif C(6). The manifestations of cooperative effects in the formation of supramolecular synthons observed were analyzed from the fully optimized clusters employing a DFT/B3LYP level of calculations, which reproduce the main features of the stereochemistry and geometries of the synthons exhibited by X-ray diffraction. Additionally, these intermolecular interactions were analyzed using Hirshfeld surfaces analysis, 2D finger print plots, shape index topological surfaces and 3D energy framework (crystal packing in terms on energy).

Automotive battery pack manufacturing – a review of battery to tab joining

Automotive battery packs used for electromobility applications consist of a large number of individual battery cells that are interconnected. Interconnection of the battery cells creates an electrical and mechanical connection, which can be realised by means of different joining technologies. The adaption of different joining technologies greatly influences the central characteristics of the battery pack in terms of battery performance, capacity and lifetime. Selection of a suitable joining technology, therefore, involves several considerations regarding electrical and mechanical properties and an assessment of production and operational conditions. Particularly, during the operation of an electric vehicle, challenges and mutual dependencies of the electrical and mechanical system emerge. The present work provides an overview of interdisciplinary challenges occurring at joints which are exposed to electrical current with a strong focus on interconnecting batteries for electric cars. It summarizes common quality criteria for the joining technologies and recombines those with criteria deduced from an electrical engineering point of view. Scientific literature concerning different joining technologies in the field of battery manufacturing is discussed based on those criteria. The most common joining techniques are ultrasonic welding, wire bonding, force fitting, soldering, laser beam welding, and resistance welding. Besides those, friction stir welding, tungsten inert gas welding, joining by forming and adhesive bonding are presented.

Minimal surfaces from infinitesimal deformations of circle packings

We study circle packings with the combinatorics of a triangulated disk in the plane and parametrize deformations of circle packings in terms of vertex rotation and cross ratios. We show that there is a Weierstrass representation formula relating infinitesimal deformations of circle packings to discrete minimal surfaces of Koebe type. Furthermore, every minimal surface of Koebe type can be extended naturally to a discrete minimal surface of general type. In this way, discrete minimal surfaces via Steiner's formula are unified.

Characterization and Correlations of CO2 Absorption Performance into Aqueous Amine Blended Solution of Monoethanolamine (MEA) and N,N-Dimethylethanolamine (DMEA) in a Packed Column

To get a more accurate mass transfer coefficient model of CO2 into aqueous monoethanolamine (MEA)/N,N-dimethylethanolamine (DMEA) solution in a packed column, the Henry’s law constant, equilibrium CO2 solubility, volumetric overall mass transfer coefficient (KGav), overall gas-phase mass transfer coefficient (KG), and effective gas–liquid interfacial area (av) were comprehensively studied. The Henry’s law constant was obtained using a jacketed stirred glass reactor, and the equilibrium CO2 solubility was investigated using a bubbling absorption reactor. Additionally, the mass transfer performance was measured and evaluated experimentally in a packed column with DX-Type structured packing in terms of KGav, KG, and av. These experiments were conducted under the MEA/DMEA concentration of 6 kmol·m–3 with ratio of 5:1. The dynamic changes of solubility, species concentration, and absorption heat of solution were analyzed under different CO2 loadings. The experimental results showed that the relationship of suc...

Packing of arborescences with matroid constraints via matroid intersection

Edmonds’ arborescence packing theorem characterizes directed graphs that have arc-disjoint spanning arborescences in terms of connectivity. Later he also observed a characterization in terms of matroid intersection. Since these fundamental results, intensive research has been done for understanding and extending these results. In this paper we shall extend the second characterization to the setting of reachability-based packing of arborescences. The reachability-based packing problem was introduced by Cs. Király as a common generalization of two different extensions of the spanning arborescence packing problem, one is due to Kamiyama, Katoh, and Takizawa, and the other is due to Durand de Gevigney, Nguyen, and Szigeti. Our new characterization of the arc sets of reachability-based packing in terms of matroid intersection gives an efficient algorithm for the minimum weight reachability-based packing problem, and it also enables us to unify further arborescence packing theorems and Edmonds’ matroid intersection theorem. For the proof, we also show how a new class of matroids can be defined by extending an earlier construction of matroids from intersecting submodular functions to bi-set functions based on an idea of Frank.

Hydraulic and Mass Transfer Performances of a Commercial Hybrid Packing: The RSP200X-Key Modelling Parameters for Gas Treatment Applications

The use of the last generation of Raschig’s structured packings, Raschig SuperPack (RSP) has been investigated for scrubbing columns operating at high liquid loads, for their potential to increase capacity while maintaining mass transfer efficiencies at high levels. IFPEN has measured pressure drops, flooding limits, liquid and gas side mass transfer coefficients and interfacial areas for the RSP 200X. Flooding limits were in agreement with literature, however at high liquid loads and for tested X-Style RSP they were 30-40% lower than those calculated with the Winsorp Software. This indicates that extrapolation of flooding models should be used with caution to size column diameters for fluid systems and liquid loads that differ from those from which these models were derived. With the support of the present results a modified version of Winsorp has been elaborated for high liquid loads and X-Style RSP. RSP 200X develops a high interfacial area, close to the one of a standard 250 m2/m3 structured packing. One important difference however has been noted about the impact of the gas flowrate on the interfacial area. While for standard packings the gas flow rate is often considered to have only a small effect on area when operating below the loading point, the effect measured on RSP200X is significant and of the same order as for liquid load. Measurements of kLae further confirm that these latest generations of packings show different trends when compared to standard structured packings. Detailed characterization tests are therefore highly recommended to estimate the performances of these packings in terms of hydraulics and mass transfer properties. In some distant future, it is believed that CFD calculations (gas and gas/liquid) will help to better understand and model such phenomena.

Compressive resistance of granular-scale microgels: From loose to dense packing

Microgels are deformable and compressible particles that can be packed to concentrations that exceed the random close packing limit of hard spheres. For reaching high packing levels, one has to overcome the resistance to compression of the system. This resistance potentially originates from many different phenomena (thermal agitation effects, surface interactions, microgel deformation, interpenetration, water expulsion) that depend on the microgel properties (size, ionic charge, structure, softness). Here, we investigate granular-scale dextran-based microgels with different native water contents. The resistance to compression of the suspensions is measured through the variation of the osmotic pressure with packing concentration. In parallel, we characterize the structure of the packings in terms of polymer heterogeneity, microgel deformation, and average size using confocal microscopy. We find that all microgel suspensions resist compression in the same manner; however, the mechanisms involved clearly depend on the actual degree of compression. In the loose packing regime, the resistance originates mainly from the resistance of the microgels to their own deformation, with no or negligible deswelling; the osmotic pressure rises abruptly with concentration in analogy to compressed emulsion droplets. In the second and dense packing regime, the microgels necessarily have to expel water to withstand compression. The resistance of the packing is then similar to that of a continuous gel of the same polymer. Importantly, we find that structural macro-voids are still observable in these systems; the presence of which needs to be taken into account when modeling the osmotic resistance.

Sustainability strategies in the Indian leather industry: an empirical analysis

PurposeBurgeoning challenges of climate change and poverty alleviation across many parts of the world have enforced the policy makers and researchers to develop an alternate system for performance assessment of an individual, a country, and a corporate. The purpose of this paper is to analyze the sustainability strategies of three leading states in the Indian leather industry – Tamil Nadu (TN), West Bengal (WB) and Uttar Pradesh (UP) – to gain insights into their efforts and progress in generating economic, social, and environmental values.Design/methodology/approachThis study used case study approach for investigative analysis, and triangulation method – interviews and field visits, for data verification. The study examines the various sustainability strategies by applying economic value creation (evaluation of growth in total turnover, evaluation of the growth in profitability, evaluation of leverage), social value creation (evaluation of the growth in wages, evaluation of the growth in employee welfare expenses), and environmental value creation (conservation in raw material consumption, conservation in energy consumption, evaluation of waste management practices).FindingsThe findings reveal that the three states differ significantly from each other both in terms of efforts made and progress achieved during the period of study, 1998-2013. UP seems to be making the most consistent progress in achieving economic value, while WB shows the most progress in creating social value, and TN leads the pack in terms of creating environmental value. Thus, the three leading states in the Indian leather industry have been allowing trade-offs to get competitive advantage over others.Research limitations/implicationsThe opaqueness with which the Indian leather Industry conducts social and environmental practices clearly limits the sources of accurate and reliable data, and the ability of researchers to precisely identify the problems and suggest solutions.Practical implicationsThe opaqueness with which the Indian leather Industry conducts social and environmental practices clearly impacts the policy makers, practitioners, and researchers to continue such initiatives and improve the lives of people in India for whom continuing this profession is a big challenge and a hurdle to accomplish their livelihood.Originality/valueThe paper gives a theoretical explanation of the sustainability in the leather industry with respect to its strategies in terms of economic value, social value, and environmental value.

Thermal-hydraulic and quench analysis of the DEMO toroidal field winding pack WP1

Three alternative designs of the toroidal field (TF) coil were proposed for the European DEMO being developed under the Eurofusion Consortium. The most ambitious TF coil winding pack in terms of technological deviation from the ITER TF coil design and consequent potential cost saving, the so-called WP1, is based on the react&wind technology of Nb3Sn layer-wound flat multistage conductors. We present the thermal-hydraulic and quench propagation analyses for the WP1 proposed in 2015, in which the realistic magnetic field and nuclear heat load maps are taken into account. The aim of the analysis, performed using the Cryosoft software, is to assess the temperature margin at the end-of-burn conditions, as well as the hot-spot temperature that is expected in case of quench, and consequently to optimize the WP1 design from the thermal-hydraulic point of view.

A hydrodynamic study of cylindrical metal foam packings: Residence time distribution and two phase pressure drop

The present study deals with hydrodynamic characterization of a cylindrical metal foam packings in terms of wetting efficiency, residence time distribution and pressure drop. It was shown that the operation of foam packings in liquid downward flow does not lead to an optimal wetting efficiency according to very high void volume and is very sensitive to the wall issues i.e. fabrication tolerances in the range of 100μm, Therefore, the study was performed for an upward flow operation mode. The RTD measurements in liquid upward flow and gas/liquid co-current upward flow revealed that the axial backmixing in the foam packing was less than in a vertical pipe with the same diameter. Furthermore, it was shown that the two phase pressure drop for 30 PPI and 45 PPI pore densities were below 250Pam−1 and 350Pam−1 respectively. The energy dissipation of 30 and 45PPI foam packings were below 1Wm−3 indicating a very energy efficient type of packing.

The compression–error trade-off for large gridded data sets

Abstract. The netCDF-4 format is widely used for large gridded scientific data sets and includes several compression methods: lossy linear scaling and the non-lossy deflate and shuffle algorithms. Many multidimensional geoscientific data sets exhibit considerable variation over one or several spatial dimensions (e.g., vertically) with less variation in the remaining dimensions (e.g., horizontally). On such data sets, linear scaling with a single pair of scale and offset parameters often entails considerable loss of precision. We introduce an alternative compression method called "layer-packing" that simultaneously exploits lossy linear scaling and lossless compression. Layer-packing stores arrays (instead of a scalar pair) of scale and offset parameters. An implementation of this method is compared with lossless compression, storing data at fixed relative precision (bit-grooming) and scalar linear packing in terms of compression ratio, accuracy and speed. When viewed as a trade-off between compression and error, layer-packing yields similar results to bit-grooming (storing between 3 and 4 significant figures). Bit-grooming and layer-packing offer significantly better control of precision than scalar linear packing. Relative performance, in terms of compression and errors, of bit-groomed and layer-packed data were strongly predicted by the entropy of the exponent array, and lossless compression was well predicted by entropy of the original data array. Layer-packed data files must be "unpacked" to be readily usable. The compression and precision characteristics make layer-packing a competitive archive format for many scientific data sets.

Mass transfer performance of CO2 absorption into aqueous DEEA in packed columns

A bench-scale absorption column packed with high efficiency Sulzer DX-type packing was used to determine the volumetric overall mass transfer coefficient (KGav) for CO2 absorption into an aqueous solution of DEEA. The effects of the main operating parameters, such as liquid feed temperature, DEEA concentration, lean CO2 loading, liquid flow rate, CO2 partial pressure, and inert gas flow rate were examined. The results showed that DEEA concentration, CO2 lean loading, and liquid flow rate had a significant effect on KGav while inert gas flow rate had little effect. In addition, CO2-loaded aqueous DEEA solution was observed to have a higher KGav as compared to that of aqueous MDEA solutions. Also, the performance of CO2 absorption with DEEA in structured packing in terms of KGav and cyclic capacity (Δα) were compared with the performance in a random packing column. The structured packing column performed better than the random packing column. Finally, two experimental KGav correlation models for CO2-DEEA system were proposed and found to be in satisfactory agreement with experimental results with AAD of 8 and 3%, respectively.

The load-balanced multi-dimensional bin-packing problem

The bin-packing problem is one of the most investigated and applicable combinatorial optimization problems. In this paper we consider its multi-dimensional version with the practical extension of load balancing, i.e. to find the packing requiring the minimum number of bins while ensuring that the average center of mass of the loaded bins falls as close as possible to an ideal point, for instance, the center of the bin. We formally describe the problem using mixed-integer linear programming models, from the simple case where we want to optimally balance a set of items already assigned to a single bin, to the general balanced bin-packing problem. Given the difficulty for standard solvers to deal even with small size instances, a multi-level local search heuristic is presented. The algorithm takes advantage of the Fekete–Schepers representation of feasible packings in terms of particular classes of interval graphs, and iteratively improves the load balancing of a bin-packing solution using different search levels. The first level explores the space of transitive orientations of the complement graphs associated with the packing, the second modifies the structure itself of the interval graphs, the third exchanges items between bins repacking proper n-tuples of weakly balanced bins. Computational experiments show very promising results on a set of 3D bin-packing instances from the literature.

English

PURPOSE OF STUDY: Nasal dressing following nasal surgery in an attempt to prevent postoperative bleeding and to modulate the wound healing process. Experience with postoperative nasal dressings in otolaryngologic literature spans more than half a century; despite of this, there is still little agreement between the surgeons on the appropriate choice of nasal dressings following nasal surgery, or whether nasal dressings are required at all. This paper briefly reviews the comparative study between the postoperative cases with and without nasal dressings. STUDY DESIGN: It is a prospective study carried out in a tertiary care, teaching hospital. MATERIALS AND METHODS: A prospective evaluation of patients who underwent nasal surgery at tertiary teaching hospital setting between February 2013 to June 2014 was performed. Nasal dressing was done in some cases who underwent nasal surgery and no dressing was done in some cases. The comparative results between the cases with and without nasal packing in terms of Postoperative bleeding, Adhesion formation, Middle turbinate lateralization were studied. RESULTS: Out of 160 patients included in this study, nasal dressing postoperatively was done in 92 cases and 68 cases were not packed postoperatively. In terms of postoperative bleeding there is no significant difference between the cases with packs (5.43%) and without pack (5.88%). Postoperative Adhesion formation was less in cases without nasal packing (2.94%) than in cases with nasal dressing (8.7%). Middle turbinate lateralization is also less in cases without nasal packing (8.82%) than in cases with nasal packing (17.5%). CONCLUSION: The decision as to whether to pack the nose after nasal surgery remains controversial. There has been an increasing tendency to move away from removable nasal dressings due to discomfort and bleeding upon removal and also postoperative adhesions. This study showcases that there is no considerable difference in postoperative bleeding in patients with or without nasal dressings postoperatively. It also shows that wound healing is better and middle turbinate lateralization is less significant in cases without nasal packings than in cases with post- operative nasal dressings.

Adhesive loose packings of small dry particles.

We explore adhesive loose packings of small dry spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics and statistical ensemble theory. A dimensionless adhesion parameter (Ad) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for Ad > 1. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes the correlation between bulk and contact spheres. Our theoretical and numerical results predict: (i) an equation of state for adhesive loose packings that appear as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram and (ii) the existence of an asymptotic adhesive loose packing point at a coordination number Z = 2 and a packing fraction ϕ = 1/2(3). Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing (RLP), which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

ChemInform Abstract: Chalcogenide Derivatives of 1,2,5‐Triphenyl‐1H‐phosphole: Structure and Photophysical Properties.

Abstract Chalcogenide derivatives of triphenylphosphole (oxide ( 1 ), sulfide ( 2 ) and selenide ( 3 )) were synthesized and characterized by X-ray diffraction studies. Intermolecular interactions were observed in the bulk molecular packing in terms of hydrogen bonding for 1 or π–π stacking for 3 . One of the useful applications of the chalcogenide derivatives of triphenylphosphole has been demonstrated utilizing the photophysical properties of 1 to detect aromatic nitro compounds through fluorescence quenching.

Stability Analysis of Converter-Connected Battery Energy Storage Systems in the Grid

This paper analyzes the stability of a battery energy storage system (BESS) connected to the grid using a power-electronic interface. It is shown that the internal resistance and internal voltage of the battery affect system stability. Variations in these parameters may occur due to aging and changes in the state-of-charge (SoC). Using average-value modeling, this problem is framed into a nonlinear system formulation and the region of stability as a function of the internal resistance and the internal voltage of the battery is determined. This paper also extends its results in determining the configuration of a battery pack in terms of the number of battery cells in series and parallel to prevent instability while meeting demand power requirements. The findings are useful both in the design and operation stages of large-scale battery storage systems in the grid.

Statistics of frictional families.

We develop a theoretical description for mechanically stable frictional packings in terms of the difference between the total number of contacts required for isostatic packings of frictionless disks and the number of contacts in frictional packings, m=Nc0 - Nc. The saddle order m represents the number of unconstrained degrees of freedom that a static packing would possess if friction were removed. Using a novel numerical method that allows us to enumerate disk packings for each m, we show that the probability to obtain a packing with saddle order m at a given static friction coefficient μ, Pm(μ), can be expressed as a power series in μ. Using this form for Pm(μ), we quantitatively describe the dependence of the average contact number on the friction coefficient for static disk packings obtained from direct simulations of the Cundall-Strack model for all μ and N.

Polymorphism in two biologically active dihydropyrimidinium hydrochloride derivatives: quantitative inputs towards the energetics associated with crystal packing.

A new polymorph belonging to the tetrahydropyrimidinium class of compounds, namely 6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-2-(3-(trifluoromethylthio)phenylamino)-3,6-dihydropyrimidin-1-ium chloride, and a hydrate of 2-(3-bromophenylamino)-6-(4-chlorophenyl)-5-(methoxycarbonyl)-4-methyl-3,6-dihydropyrimidin-1-ium chloride, have been isolated and characterized using single-crystal X-ray diffraction (XRD). A detailed comprehensive analysis of the crystal packing in terms of the associated intermolecular interactions and a quantification of their interaction energies have been performed for both forms of the two different organic salts (A and B) using X-ray crystallography and computational methods such as density functional theory (DFT) quantum mechanical calculations, PIXEL lattice-energy calculations (with decomposition of total lattice energy into the Coulombic, polarization, dispersion and repulsion contribution), the calculation of the Madelung constant (the EUGEN method), Hirshfeld and two-dimensional fingerprint plots. The presence of ionic [N-H](+)···Cl(-) and [C-H](+)···Cl(-) hydrogen bonds mainly stabilizes the crystal packing in both forms A and B, while in the case of B·H2O [N-H](+)···O(water) and O(water)-H···Cl(-) hydrogen bonds along with [N-H](+)···Cl(-) and [C-H](+)···Cl(-) provide stability to the crystal packing. The lattice-energy calculations from both PIXEL and EUGEN methods revealed that in the case of A, form (I) (monoclinic) is more stable whereas for B it is the anhydrous form that is more stable. The analysis of the `Madelung mode' of crystal packing of two forms of A and B and its hydrates suggest that differences exist in the position of the charged ions/atoms in the organic solid state. The R/E (distance-energy) plots for all the crystal structures show that the molecular pairs in their crystal packing are connected with either highly stabilizing (due to the presence of organic R(+) and Cl(-)) or highly destabilizing Coulombic contacts. The difference in crystal packing and associated intermolecular interactions between polymorphs (in the case of A) or the hydrates (in the case of B) have been clearly elucidated by the analysis of Hirshfeld surfaces and two-dimensional fingerprint plots. The relative contributions of the various interactions to the Hirshfeld surface for the cationic (dihydropyrimidinium) part and anionic (chloride ion) part for the two forms of A and B and its hydrate were observed to be different.

Quantitative Crystal Structure Analysis of (E)-1-[(2-Chloro-1,3-thiazol-5-yl)methyl]-3-methyl-2-nitroguanidine

The crystal structure of a biologically active (E)-1-[(2-chloro-1,3-thiazol-5-yl)methyl)]-3-methyl-2-nitroguanidine with molecular formula C6H8N5O2ClS has been investigated based on the molecular conformation and the supramolecular packing in terms of intermolecular interactions involving N–H⋯O, N–H⋯N, and C–H⋯O–N (nitro group), C–H⋯N (thiazol) hydrogen bonds, offset π–π stacking, C–H⋯π and N(–NO2)⋯C=N intermolecular interactions. Furthermore, a short C–Cl⋯O–N contact is also present which contributes towards the crystal packing. The lattice energy of the title compound has been calculated using the PIXEL approach (the Coulomb-London-Pauli (CLP) model) and compared with periodic calculations performed using CRYSTAL09. In addition, Hirshfeld surface analysis and fingerprint plots provide a platform for the evaluation of the contribution of different intermolecular interactions towards the packing behaviour.