Packing Of Sheets Research Articles

Physical therapy and quality of life: Design and results of a study on hydrotherapy

We proposed to use physical therapy in addition to the well-known physiological effects influencing the emotional state. 24 patients allocated to our department, suffering from chronic cardiac, rheumatic, and metabolic diseases, as well as functional disorders, received a cold-wet sheet pack on the trunk. The control group received a dry sheet pack, undergoing exactly the same procedure, but without the stimulus of hydrotherapy. We focused on the change of acute mental state in both groups. We used two questionnaires which had been evaluated by the Psychiatric Information System of D. v. Zerssen in Munich. Our results showed significant differences in the outcome of both applications: the mental well-being was affected positively in 18 patients during the real treatment, compared with 9 in the control group. (Wilcoxon matched-pairs signed-ranks text 2 p< 0.0025). The interpretation shows a clear trend towards a better mental balance after experiencing the stimulus of hydrotherapy.

Structure and function of the DNA repair enzyme exonuclease III from E. coli.

The three-dimensional structure of exonuclease III, the major AP DNA repair endonuclease of Escherichia coli, has been determined using x-ray crystallographic methods at 2.7 A resolution. The atomic model was fit to an electron density map calculated with phases obtained from three isomorphous heavy atom derivatives. The overall chain fold of exonuclease III is that of a compact alpha,beta-protein of dimensions 55 by 50 by 45 A. The pair of extended beta-pleated sheets pack against each other in an approximately parallel fashion to form the hydrophobic core of a four-layered sandwich structure. These beta sheets are flanked by four alpha-helices that form the outer two layers of the fold. The individual strands of the beta-sheets are in a mostly antiparallel configuration and are linked by extensive loop regions that connect adjoining strands. The structure contains internal symmetry with the two extended beta-sheets and four alpha-helices related by a pseudo-twofold axis running approximately down the center of the two sheets. This internal symmetry is not mirrored in the structure of the loop regions, nor is it detectable within the amino acid sequence. There is a "groove" between the beta-sheets at one end of the molecule that is bordered by several of the exposed loop regions and may be significant for DNA binding.

Formation and stability of secondary structures in globular proteins

We study two models for the formation and packing of helices and sheets in globular (compact) proteins. These models, based on weighted Hamiltonian paths on a regular lattice both exhibit a first order transition between a compact high temperature phase, with no extended secondary structures, and a quasi-frozen compact phase, with secondary structures invading the whole lattice. The quasi-frozen phase with very weak temperature dependence, is identified as the native phase of proteins, whereas the high-temperature phase may be relevant to the so-called molten globule state of proteins

Protein-protein recognition and the association of immunoglobulin constant domains

Four immunoglobulin constant domain interfaces were analysed to determine how the light and heavy chains of the domains recognize each other and secondarily, why the packing of the beta sheets is different from that normally observed in the interior of domains of beta sheet proteins. It was found that two bulky groups in the centre of each of the domain interfaces prevent the alignment of sheet axes by intercalating with residues in the sheet opposite. This intercalation forms the basis of constant domain light chain-heavy chain recognition.

Automation of the packing of tinplate sheets and coils in steel covers

Automation of the packing of tinplate sheets and coils in steel covers

アルミナの粒径とフラックスの比表面積がアルミナ基板の焼結特性に及ぼす影響

We studied the effects of alumina particle diameter and flux specific surface area on the sinterability of alumina substrate in relation with the powder packing density.Alumina particle diameter and flux specific surface area were varied within the ranges from 0.5 to 3.6μm and from 1 to 100 m2/g, respectively. The larger the alumina particle diameter, the higher became the minimum sintering temperature. The minimum sintering temperature of alumina substrate decreased by about 50°C when agglomerated particles were pulverized and packing density was improved. On the other hand, the effect of flux specific surface area was insignificant on minimum sintering temperature. Saturated sintered density remained almost unchanged when the alumina particle diameter was varied.However, it became higher when agglomerated alumina particles were pulverized. Surface smoothness was improved significantly when agglomerated particles were pulverized and hence the green sheet packing density increased.

The dynamics of freely decaying two-dimensional turbulence

Direct numerical simulations of decaying high-Reynolds-number turbulence are presented at resolutions up to 8002 for general periodic flows and 20482 for periodic flows with large-scale symmetries. For turbulence initially excited at large scales, we characterize a transition of the inertial energy-spectrum exponent from n ≈ − 4 at early times to n ≈ − 3 when the turbulence becomes more mature. In physical space, the first regime is associated with isolated vorticity-gradient sheets, as predicted by Saffman (1971). The second regime, which is essentially statistical, corresponds to an enstrophy cascade (Kraichnan 1967; Batchelor 1969) and reflects the formation of layers resulting from the packing of vorticity-gradient sheets. In addition to these small-scale structures, the simulation displays vorticity macro-eddies which will survive long after the vorticity-gradient layers have been dissipated (McWilliams 1984). We validate the linear description of two-dimensional turbulence suggested by Weiss (1981), which predicts that coherent vortices will survive in regions where vorticity dominates strain, while vorticity-gradient sheets will be formed in regions where strain dominates. We show that this analysis remains valid even after vorticity-gradient sheets have been formed.

Scrubbing in packed columns of gases from soda-regeneration boiler complexes

The treatment of gases from the soda-regeneration boilers in sulfate cellulose pulping plants is intended for the removal of dust and sulfur dioxide from the gases and for the recovery and utilization of their heat. In this paper the authors investigate the possibility of using columns of KhOLPAK horizontal sheet packings for cleaning the stack gases. The packings consist of sheets of punched and drawn metal arranged at fixed distances in a horizontal configuration. Spray nozzles are used to wet the surface area. Calculations and design parameters are carried out depicting the flow characteristics of the gases and sprays in both counterflow and concurrent flow scrubbers.

Bestimmung des spreitungskoeffizienten bei einer horizontalen streckmittelpackung

Investigations are reported aimed at determining the distribution coefficient of a horizontal expanded sheet packing, depending on the flow rate of a single jet as well as on the geometrical dimensions of the packing. An empirical relation for its determination has been derived. The high distribution coefficient makes the possibility of using that device as a redistribution layer very promising.

The effect of surface active agents on the mass transfer coefficient in vertical film flow of liquid over the surface of expanded metal sheet packing

Experimental data have been used on absorption of poorly soluble gases, helium, carbon dioxide, and propane, to study the mechanism of interfacial mass transfer in vertical gravitational film flow down the surface of the expanded metal sheet. It has been found that upon addition of surface active agents into water, the original almost freely moving liquid-gas interfacial surface behaves similarly as a liquid-solid surface. Two adjustable hydrodynamic parameters have been evaluated on the basis of the film penetration theory with the physical meaning of the dimensionless thickness of an unmixed region near the interface ϑ+ = 0.4 and the characteristic length &lt; scale of the disturbance λ+ = 26.4.

Flow-by electrodes of ordered sheets of expanded metal—I. Mass transfer and current distribution

The paper is an experimental study concerning mass transfer and the current distribution within flow-through electrodes obeying a perpendicular configuration and made by ordered packing of sheets of expanded metal. The mesh size, the orientation of the mesh with respect to the electrolyte flow direction and the respective arrangement of the sheets are the geometrical parameters of the study.

A new crystalline modification of nylon 10

A new crystalline modification of nylon 10, named α ∗, was obtained by evaporating a solution of the polymer in formic acid. The XRD pattern analysis indicates a chain packing similar, in the c axis projection, to that of melt-crystallized α-nylon 6 but indicates a reflection impossible to be indexed on the basis of a monoclinic lattice. By examining the XRD pattern of an oriented sample of α ∗- nylon 10 , it was found that the polymer crystallizes in the triclinic system. Calculation gave the following cell parameters: a = 9.80 A ̊ ; b = 5.12 A ̊ ; c = 27.54 A ̊ ; a = 54°; β = 90°; γ = 110° . The most reliable structural hypothesis corresponds to a sheet packing of antiparallel planar chains linked by hydrogen bonds. These sheets (parallel to the ac plane), are spaced at 3.74 Å, nearly as in α-nylon 6, and progressively shift at a constant value (3.03 Å) along the c axis direction; also the sheets of α-nylon 6 are displaced by a constant value (3.73 Å) along the c direction, but alternately up and down.

Ergebnisse einer Untersuchung der Gasverteilung über dem Querschnitt einer Füllkörperkolonne

The gas distribution has been investigated over a cross-section of a 472 mm diameter column assembled with two types of inlet devices with and without equalizing packing layer, respectively. The minimum height of Raschig rings, Pall rings, Intalox saddles and four types of horizontal expanded sheet packing, at which a uniform velocity profile can be obtained, was found. It is shown that when applying these packings no increase occurs in the velocity of the nearwall layer.

A Compact Low-Pressure Drop Desiccant Bed for Solar Air Conditioning Applications: Analysis and Design

Requirements for silica gel desiccant beds used in the “Solar-Desiccant-Evaporative Cooling System” are discussed and the advantages of laminar flow packings demonstrated. An analysis of transient heat and mass transfer in laminar flow silica gel desiccant beds is presented, together with a description of an associated computer code for the solution of the governing partial differential equations. Based on results of calculations using the code, a preliminary design of a prototype scale desiccant bed is developed for a coated sheet packing concept. Results are presented for code calculations used to determine an optimum gel particle size and to explore the effect of substrate thermal capacity on cyclic performance.

Measurement of interfacial area and intensity of mass transfer in the gas phase in a packing with significant dependence of the interfacial area on the density of irrigation

The dependence has been measured of the interfacial area and the number of transfer units for gas side resistance controlled absorption on the flow rate of gas and liquid at counter- and cocurrent flow arrangement. The measurements have been carried out for a vertical expanded metal sheet packing exhibiting a strong dependence of the interfacial area on the density of irrigation. The interfacial area has been measured by absorption of carbon dioxide into a solution of sodium hydroxide under the conditions of the pseudo first order reaction. The number of transfer units has been measured by absorption of sulphur dioxide also into a solution of sodium hydroxide. In addition, the pressure drop has been correlated against the flow rate of gas and liquid.

X-ray analysis of the eye lens protein γ-II crystallin at 1·9 Å resolution

We report the X-ray structure analysis and refinement at 1.9 A resolution of calf gamma-II crystallin, a lens-specific protein. The sequence of Croft (1972) has been modified to give a polypeptide chain of 174 residues (cf. 165). The protein has a symmetrical, hierarchical structure of two globular domains each comprising two similar "Greek key" motifs, consecutive along the polypeptide chain, and related by a pseudo 2-fold axis. The two domains pack together with a single connection and are related by a further pseudo 2-fold axis which bisects the angle between the intra-domain dyads. Forty-two pairs of C alpha positions for the two most similar motifs have root-mean-square separation at best fit of 0.69 A. The N and C-terminal domains gave root-mean-square separation of 0.89 A for 82 pairs of C alpha atoms at best fit. In each domain the two Greek key motifs form a pair of four-stranded antiparallel beta-pleated sheets, each sheet composed of three stands from one motif and one from the other. The sheets pack together in a wedge shape, closed at the top by the loops connecting the third and fourth strands of each motif. The first two strands of each motif form an extended beta-hairpin which is folded on to the beta-sheet. The packing of each motif into the globular domains involves a staggered bilayer of side-chains between each pair of beta-sheets which does not preserve the pseudo 2-fold axes observed in the C alpha position topology. In the core of each domain there are interactions between polarizable aromatic groups and sulphur-containing residues which may contribute to stability and may also serve to protect aromatic side-chains from ultraviolet light damage in the lens. At the surface of the molecule over half the ionic side-chains are closely paired, which probably stabilizes the tertiary fold and may reduce the water bound. Crystal lattice interactions are described which may be similar to those occurring in vivo in the lens between crystallins. Seven cysteine residues have been identified in the structure and these may have a role in the thermodynamic stability of the molecule, its intermolecular interactions under the normal reducing conditions of the lens, and also in the aggregation and cross-linking which occur in some forms of cataract. Three of these residues, Cys18, Cys23 and Cys74, form a cluster in the N-terminal domain.(ABSTRACT TRUNCATED AT 400 WORDS)

Relative orientation of close-packed β-pleated sheets in proteins

When beta-pleated sheets pack face to face in proteins, the angle between the strand directions of the two beta-sheets is observed to be near -30 degrees . We propose a simple model for beta-sheet-to-beta-sheet packing in concanavalin A, plastocyanin, gamma-crystallin, superoxide dismutase, prealbumin, and the immunoglobin fragment V(REI). This model shows how the observed relative orientation of two packed beta-sheets is a consequence of (i) the rows of side chains at the interface being approximately aligned and (ii) the beta-sheet having a right-handed twist. The special amino acid composition of residues at the beta-sheet-to-beta-sheet interfaces makes the contact surfaces essentially smooth and hydrophobic.

Structural classification and properties of the layered oxides

Layer oxides with formula AxMO2 where M stands for a transition element with two oxidation states or for a mixture of tetravalent and trivalent (or eventually divalent) elements are obtained for 0.5 ≤ x ≤ 1. The lattice is built up by sheets of edge sharing MO6 octahedra between which the alkali ions are inserted with trigonal prismatic or octahedral environment. Similar structures can be found among A2MO3 oxides, the alkali ions lying between (A13M23)O2 sheets. The influence of the pressure on the stability of the various packings is discussed. Layer structures are also obtained for the compositions Li8MO6, Li7L□O6 and Li6In2□O6. Structures of these pseudo-2D materials are characterized by a packing of octahedral and tetrahedral sheets where the alkali ions and the vacancies are distributed. Transport properties of these materials have been studied.

The gass-side mass transfer coefficient and the interfacial area under the turbulent flow over the packing of parallel expanded metal sheets

Specific interfacial area has been computed from experimental values of the gas-side volume mass transfer coefficient, kga, and the theoretically derived expressions for gas-side mas transfer coefficient per unit area of interfacial surface, kg. The results have been compared with the specific interfacial area determined experimentally using the chemical method.

Liquid side mass transfer coefficient and interfacial area at vertical liquid flow on expended metal sheet packing

Prediction of the liquid side mass transfer coefficient k1 at vertical liquid flow on the expanded metal packing is based on the penetration model according to Higbie. The experimental value of mass transfer coefficient k1 at absorption of sparingly soluble gases with differing diffusivities in water (propane, carbon dioxide and helium) are in a good agreement with the predicted values in a wide range of linear wetting densities. Interfacial area is determined by the chemical method and is correlated by an empirical relation.