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  • Articles  (102)
  • Springer  (102)
  • Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics  (102)
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  • Articles  (102)
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  • 1
    Electronic Resource
    Electronic Resource
    A summary of environmental legislation targeting disposable diapers and review of related literature (1994)
    Springer
    Journal of polymers and the environment 2 (1994), S. 39-48 
    Details
    ISSN: 1572-8900
    Keywords: Disposable diapers ; degradable plastics ; environmental legislation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In recent years state and local governments, as well as private citizens, have become very concerned about the mounting solid waste disposal problem facing our nation. Special concern has been expressed over the presence of disposable diapers in the solid waste stream. Responding to the concerns, legislators in at least 25 states proposed actions regarding disposable diapers between 1990 and 1992. Several factors contributed to the number of legislative proposals regarding disposable diapers over the past few years. First was the public's and legislators' misconception about the contribution of disposable diapers to the solid waste stream. Second was an erroneous assumption held by the public and some legislators that biodegradation readily occurs in landfills. Third was the desire to increase demand for agricultural products by requiring the use of “degradable” products. These contributing factors and other issues surrounding the proposal and passage of environmental legislation pertaining to disposable diapers are presented in this paper and the relevant literature is summarized. To provide the necessary context, the paper contains a review of the literature concerning disposable diapers, their composition and usage; and their environmental impact and fate and a comparison of their performance and cost to those of cloth diapers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02073485
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  • 2
    Electronic Resource
    Electronic Resource
    Crystallization behavior of predominantly syndiotactic poly(β-hydroxybutyrate) (1995)
    Springer
    Journal of polymers and the environment 3 (1995), S. 37-47 
    Details
    ISSN: 1572-8900
    Keywords: Poly(3-hydroxybutyrate) ; ring-opening polymerization ; syndiotactic ; syndioregularity ; crystallization ; thermal properties ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Predominantly syndiotactic poly(β-hydroxybutyrate), syn-PHB, of variable syndioregularity (syndyad fractions 0.59, 0.62, 0.64, and 0.71) and molecular weight was prepared by the dibutyltin dimethoxide catalyzed ring opening of racemicβ-butyrolactone (BL). The crystallization behavior of the syn-PHB polymers was investigated by DSC and X-ray diffraction analyses. DSC of films after melting and annealing showed at least one, and often two distinct melting transitions occuring over a broad (often ∼ 40°C) temperature range. These results indicate that syn-PHB chain segments of variable syndioregularity form crystalline regions with very different thermodynamic stabilities. Maximum degrees of crystallinity for melt annealed 0.64- and 0.71-syn-PHB was observed at an annealing temperature (T c ) of 30°C. AtT c values at 45°C and higher, crystallization of relatively lower syndioregular chain segments was apparently excluded to variable degrees dependent onT c and sample syndiotactic dyad content. After crystallization of syn-PHB samples at elevated temperatures, ambient temperature annealing resulted in an observed lower temperature melting transition at ∼ 50°C. This result showed little to no dependence on syn-PHB syndio-regularity andT c . Both solution precipitated 0.62-syn-PHB and 0.71-syn-PHB have WAXS patterns with poorly resolved crystalline reflections superimposed on amorphous haloes indicating low levels of crystallinity (17% and 25%, respectively) and poorly formed crystals. Isothermal crystallization monitored by DSC showed that the syn- and natural origin PHB showed fastest crystallization rates at temperatures between ∼ 50°C and 70°C and 60°C and 90°C, respectively. From the dependence of the higher melting transition onT c it was determined that the equilibrium melting temperatures for 0.62-syn-PHB (M n =83,700 g/mol) and a 0.64-syn-PHB (M n =11,900 g/mol) were ∼ 157 and 154°C, respectively. An Avrami analysis of syn-PHB yielded results similar to that found for natural origin PHB indicating that crystal growth occurs by a two-dimensional mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02067792
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  • 3
    Electronic Resource
    Electronic Resource
    Dendritic surface structures on excimer-laser irradiated PET foils (1993)
    Springer
    Applied physics 56 (1993), S. 329-333 
    Details
    ISSN: 1432-0630
    Keywords: 42.60 ; 61.80 ; 68.35
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A new kind of surface structure was observed on polyethylene-terephthalate (PET) foils after 248 nm KrF-excimer-laser irradiation in vacuum. The laser fluences employed were around the ablation threshold. The branched fractal structures observed have a lateral dimension in the micrometer range and a heigth of 30 to 60 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324351
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  • 4
    Electronic Resource
    Electronic Resource
    Measuring the two-dimensional structure of a wavy water surface optically: A surface gradient detector (1994)
    Springer
    Experiments in fluids 17 (1994), S. 225-237 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new method of measuring the slopes of a water surface covered with short waves is developed. A camera is placed far above the water surface looking downward so that it receives only approximately vertical rays of light emerging from the water surface from a source below. A large lens is positioned horizontally underwater. A plane light source in the form of a translucent colored screen is placed horizontally in the focal plane below this lens. Corresponding to each value of water surface slope, regardless of observer position, there is one and only one point of origin on the color screen from which light rays can enter the camera. When the color screen has a suitable two-dimensional color pattern, we are able to detect the gradient of the surface elevation throughout the field of view of the camera. This refraction slope detector has been used to find statistical properties of short wind waves in a wind-wave channel where a broad angular beam width of capillary ripples and short gravity waves contribute to the surface slopes. In these experiments waves were generated by winds ranging from 5 m/s to 10 m/s at a fetch of 24 m. The wavenumber spectra of short wave slopes have two distinguishing features: a dip at the capillary-gravity transition and steep slopes in the capillary range. Surface shapes resembling the shape of solitary capillary-gravity waves have been found from profiles of wave elevation deduced by integration of the elevation gradient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203041
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  • 5
    Electronic Resource
    Electronic Resource
    Optimization of annular fins on a horizontal tube (1974)
    Springer
    Heat and mass transfer 7 (1974), S. 87-93 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Rohre mit gleichabständlichen Kreisrippen gleicher Dicke werden für Wärmeaustauscher häufig verwendet. Hier wird ein analytisches Modell entwickelt und der damit berechnete Gesamtwärmeübergang mit verfügbaren Meßwerten verglichen. Für die Optimierung der Rippen/Rohr-Geometrie wird ein graphisches Verfahren verwendet, das die größte Wärmeübertragung durch freie Konvektion liefert. Diese optimale Anordnung hängt ab von der Wärmeleitfähigkeit des Rippenmaterials, dem Rohrdurchmesser, dem Rippenvolumen je Rohrlänge und der Temperaturdifferenz zwischen Rohr und Umgebung. Die Ergebnisse zeigen, daß eine Rippe im so optimierten System kürzer und dicker sein muß als die allein betrachtete Rippe kleinsten Materialaufwands (also ohne Berücksichtigung der Wirkung des Rippenabstandes).
    Notes: Abstract A combination of uniform-thickness annular fins evenly spaced on a tube is a common extended-surface heat exchanger configuration. An analytical model is developed and is verified by comparing total heat transfer predicted by the model to available experimental data. A direct-pattern search technique is applied to the model to optimize the fin/ tube geometry. Optimum dimensions and spacing of fins are established to provide the maximum free convection heat transfer from a fin/tube combination. The optimum arrangement is dependent on fin thermal conductivity, tube diameter, volume of fin material per unit length of tube, and temperature difference between the tube and the surrounding air. Calculated results indicate that a fin in the optimum fin/tube system is shorter and thicker than an isolated fin optimized for minimum material (with no consideration of the effects of fin spacing).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01369516
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  • 6
    Electronic Resource
    Electronic Resource
    Sizing of heat exchangers with non-uniform coefficients (1973)
    Springer
    Heat and mass transfer 6 (1973), S. 1-2 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Für die Berücksichtigung des Einflusses eines nicht-konstanten Gesamtwärmeübergangskoeffizienten in Doppelwand-Wärmetauschern wird ein Verfahren erläutert, daß die Effektivitäts(oder Wirkungsgrad-)Methode verwendet. Der lokale Wärmeübergangskoeffizient kann sich dabei mit der lokalen Temperaturdifferenz zwischen den beiden Fluiden nach der Funktion (T-t)n ändern, wobei der Exponent „n“ individuelle Größen bei verschiedenen physikalischen Situationen berücksichtigt. Es wird ein Verfahren für die Abschätzung des geeigneten Zahlenwertes für „n“ für ein) spezielles Problem angegeben. Das Ergebnis der Untersuchung ist ein Korrekturfaktor zu den gewöhnlichen Ergebnissen der Wirkungsgrad-Methode bei konstanten Wärmeübertragungskoeffizienten.
    Notes: Abstract A technique is presented to include the effects of a non-uniform, overall heat transfer coefficient in double-pipe heat exchanger analysis using the effectiveness (or efficiency) method. The local overall coefficient is permitted to vary with the local temperature difference between the two fluids according to (T−t)n, where the exponent “n” assumes individual values for various physical situations. A procedure is provided to estimate the appropriate value of “n” for a particular problem. The development provides a correction factor to the ordinary results of the effectiveness method for uniform overall coefficients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01270698
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  • 7
    Electronic Resource
    Electronic Resource
    A constitutive formulation for anisotropic materials suitable for wave propagation computer programs—II (1994)
    Springer
    Computational mechanics 15 (1994), S. 201-223 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The constitutive relationships for an anisotropic material are established for shock wave propagation and nonlinear, large deformation computer programs, commonly referred to as hydrocodes. Stresses are formulated in terms of strains; the procedure for separating material compressibility effects (equation of state) from strength effects is formulated which permits the consistent calculation of stresses in the elastic regime, and allows the mean pressure to be defined in accordance with their scalar interpretations. Futher, this procedure permits the computation of inelastic response by scaling of deviatoric stresses, so the equivalent stress resides on a yield or failure surface, without changing the pressure. The procedure for computing the equivalent plastic strain and non-radial return to the yield surface, which results from a calculated overstress, is developed. Also, the transformation matrices for large deformation (rotation), necessary for transformation between material and geometric coordinates, are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00375030
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  • 8
    Electronic Resource
    Electronic Resource
    The corrosion of glass on the sea bed (1989)
    Springer
    Journal of materials science 24 (1989), S. 3146-3153 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Alkali-lime-silicate glasses, which have corroded on the sea bed for approximately 240 years, have been studied using scanning electron microscopy, electron-probe microanalysis, X-ray and electron diffraction, and infrared spectroscopy to quantify the nature of the decay processes. Leaching and dissolution of the glass network occurs, followed by reprecipitation of new phases to produce corrosion crusts consisting of discrete layers of striking regularity. Depth profiles of the elements in the crusts revealed them to be depleted of calcium and magnesium. Silicon was enriched at the glass-corrosion interface; aluminium was concentrated throughout the crusts; iron and sulphur were enriched at the exposed surfaces. Sodium and potassium showed less regular behaviour. Several crystalline phases were identified amongst the corrosion products, not all of which arose from the decomposition of the glass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01139033
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  • 9
    Electronic Resource
    Electronic Resource
    Scale development on impure nickel at high temperatures (1992)
    Springer
    Oxidation of metals 37 (1992), S. 373-387 
    Details
    ISSN: 1573-4889
    Keywords: nickel oxidation ; scale structure ; oxygen tracer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The growth of scales on impure Ni at 1373 and 1473 K was examined by microscopy and by oxygen-tracer-imaging techniques. The outward transport of cations was the basic rate-controlling step, and on the simple initial columnar scales such cation movement was the only kinetic process. However, oxygen movement was essential for the continued growth of more complex scales. Three types of sub columnar oxide were observed: (1) relatively coarse equiaxed crystals, (2) fume-like crystals, and (3) oxide that filled the pores between the crystals of the first two types. The oxygen for the first two types was provided by dissociation of the base of the columnar layer and also from voids that developed in the columnar layer. Oxygen for the third type came directly from the atmosphere following scale cracking. Such cracks healed after forming. The origin of the major features of scales was accounted for.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00666626
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  • 10
    Electronic Resource
    Electronic Resource
    Catastrophic oxidation of zircaloys in fused salts at 300°C (1971)
    Springer
    Oxidation of metals 3 (1971), S. 399-430 
    Details
    ISSN: 1573-4889
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Very rapid oxide film growth and severe intergranular penetrating oxidation of unstressed Zircaloy specimens has been observed infused eutectic mixtures of NaNO3-KNO3-NaCl and NaNO3-KNO3-KBr at 300°C. Studies of the oxide films produced have shown that the accelerated film growth rate is associated with a change in oxide crystallite morphology, which affects the ionic transport process, coupled with a large decrease in the electronic resistivity of the oxide. The onset of intergranular penetration is determined by the development of porosity in the surface layer; no gross cracking or spalling of the oxide occurs until a late stage in the deterioration of the specimen. The penetrating intergranular oxidation does not stifle itself because an open channel is maintained along the plane of the original grain boundary surface. Severe attack in air or steam can be caused by minute deposits on specimens of NO′3-Cl′ salts which are molten at the oxidation temperature. Examples of such attack in-reactor have been identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00604043
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