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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial and engineering chemistry 18 (1979), S. 86-91 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 11 (1958), S. 93-97 
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 10 (1957), S. 364-368 
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International journal of biometeorology 13 (1969), S. 81-86 
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Die weitverbreitete Ansicht, dass man kaltes Wetter in feuchter Luft als kälter empfindet als wenn sie trocken ist, wurde an bekleideten Versuchspersonen untersucht. Das subjektive Empfinden von Kälte und Feuchte bei 6 Versuchspersonen, die eine Strecke van 1/2 Meile im Winter im Freien gingen, wurde mit Messungen der Temperatur, der relativen Luftfeuchte und anderer meteorologischer Parameter verglichen. Die Beobachtungen der Versuchsteilnehmer zeigten, dass bei kaltem Wetter die Menschen meinen, dass es feucht sei, wenn gleichzeitig der Himmel bedeckt war, und zwar unabhängig von der relativen Feuchte. Wenn man diese Meinung jedoch berücksichtigt, scheint eine gewisse Beziehung zwischen dem subjektiven Feuchtegefühl und der relativen Feuchte zu bestehen. Sie scheint einen Einfluss darauf zu haben, als wie kalt man es bei tiefen Temperaturen empfindet, aber nur in begrenztem Ausmass und umgekehrt, als die allgemeine Ansicht lautet.
    Abstract: Resume On a cherché à vérifier l'opinion généralement répandue que l'on ressent plus désagréablement un temps froid si l'air est humide que s'il est sec.Pour cela, on a interrogé des personnes vêtues qui avaient parcouru 1/2 mille à pieds. On a mis en regard les unes des autres d'une part leurs sensations subjectives de froid et d'humidité et d'autre part la température et l'humidité ambiantes ainsi que d'autres paramètres météorologiques. Les indications des personnes interrogées montrent que l'homme croit, quand il fait froid, que l'air est humide si le ciel est couvert et cela indépendamment de l'humidité relative effective. Cependant, si l'on tient compte de cette constatation, il semble qu'il y ait effectivement une relation entre la sensation d'humidité et l'humidité relative. L'humidité relative semble donc avoir effectivement des répercussions sur le degré de froid ressenti, mais seulement dans des proportions restreintes et en sens inverse de la croyance populaire.
    Notes: Abstract The widely held view that in cold weather one feels colder when the atmosphere is damp than when it is dry was investigated on clothed subjects. Subjective coldness and dampness, determined by a panel of six people who walked about half a mile in the open in winter, were compared with measurements of temperature, relative humidity, and other meteorological variables. The panellists comments showed that when the weather is cold, people think it is damp when the sky is overcast, irrespective of relative humidity. However, when this factor has been allowed for there still appears to be some correlation between subjective dampness and relative humidity. Relative humidity does appear to have an effect on how cold one feels at low temperatures, but only to a limited extent, and in the opposite direction to popular belief.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 24 (1989), S. 4068-4075 
    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 Controlled matrix shrinkage composites have resin matrices in which the cure shrinkage is controlled by adding expanding monomers to epoxy (and other) resins. The shrinkage stresses can be reduced to about one third of their normal values, accompanied by a 50% increase in impact resistance of the composites, with no corresponding loss of shear strength. Tensile and compressive properties of the composites are slightly reduced, although the resin matrices themselves have slightly improved properties as a result of the addition of the expanding monomer. In contrast to this, the addition to the resin matrix of a compatible solvent, dimethyl formamide, had very little effect on the shrinkage stress or composite impact strength but caused losses of resin properties which were manifested in a decrease in composite shear strength.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 25 (1990), S. 1197-1202 
    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 During fatigue of aligned fibre pultrusions, the flexural modulus decreases continuously when the applied stresses are tensile and directed along the fibres (R=0.1). In addition, the Poisson's ratio increases continuously, and so does the energy absorbed during the fatigue cycle. Holes in the specimens continuously increase in size in a direction at right angles to the applied stress, but change little in the stressing direction. These effects are enhanced by including compressive stresses in the cycle (R=−0.3) and are reduced by reducing the polymer cure shrinkage pressure. There are notable similarities between fatigue failure and compressive failure in aligned fibre composites, and evidence that matrix stresses are produced at right angles to the fibres, which are probably large enough to cause matrix fatigue failure. These observations lead to the conclusion that the fatigue failure may well originate from misaligned fibres, which generate off-axis stresses. These cause interface failure and polymer fragmentation, which can then lead to fibre failure (and thus composite failure) even when the applied stresses are always tensile.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 27 (1992), S. 925-929 
    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 Single-fibre pull-out experiments were carried out on samples which had been immersed in water at 22°C, 60°C and 75°C for periods of up to 13 000 h. A curve-fitting technique was used to estimate the pressure and coefficient of friction during sliding, as the fibre was pulled out of the polymer. The immersion reduced the pressure from about 16 M Pa to about 6 M Pa for immersion at 75°C. The effect was much smaller at 60°C and still less at 22°C. The results indicated that, except at 75°C, the pressures were governed by the thermal and chemical shrinkages, water dilation of the polymer, and the change in Young's modulus of the polymer caused by the water. At 75°C the apparent thermal shrinkage stress was anomalously low, taking into account the dilatation and plasticization of the resin. This could have been due to some slight dissolution of the glass by the water. The coefficient of friction was reduced, possibly by softening of the interphasial material when silanes were present. When the silane coating was removed the friction did not appear to obey Amontons law and it was concluded that a water film was probably present at the interface.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1981), S. 2837-2845 
    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 New experimental results have made necessary the reformulation of the theory for compressive strength. The new theory is based on the precept that a number of different mechanisms can cause composite failure. The active one in a particular situation is that which gives the lowest failure stress. Thus composite strength can be dominated by fibre strength when the fibres are ductile, or controlled by matrix yielding when the matrix is soft. Lack of linearity in the fibres has a very important effect also, as does the adhesion between the matrix and the fibres. Modulus is affected as well as strength. Governing equations are developed for six different mechanisms and the agreement with experiment is very good. It is concluded that to make composites with good compressive properties the fibres should be hard, as straight as possible and well bonded to the matrix. The matrix should have a high yield stress, tensile strength and compressive strength. Hybridization is useful to improve the compressive strength of Kevlar composites, but should be avoided with brittle fibre systems due to unfavourable “hybrid effects”.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1981), S. 2831-2836 
    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 Experiments carried out on pultruded fibre reinforced polyester resins show that, at moderate fibre volume fractions, the compressive strength of aligned fibre composites depends linearly on the volume fraction. The strength falls off when the fibre volume fraction,V f=0.4 with Kevlar and high strength carbon fibres. The effective fibre strength atV f〈0.4 is much less than the tensile strength but it is close to the tensile strength with E-glass fibres and high modulus carbon fibres. Poor adhesion between fibres and matrix reduces the compressive strength, as does kinking the fibres when the fibre radius of curvature is reduced to below 5 mm. Misalignment of the fibres reduces the compressive strength when the average angle of misalignment exceeds about 10° for glass and carbon fibres. However, with Kevlar no such reduction is observed because the compression strength of Kevlar reinforced resin is only a very little better than that of the unreinforced resin.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    International journal of fracture 11 (1975), S. 479-488 
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résué Dans la plupart des matériaux, et notamment les métaux, l'écoulement plastique survient à une contrainte nettement inférieure à la résistance théorique. On peut donc s'attendre à ce que des fissures dans un matériau sous contraintes aient une largeur finie, résultat d'un écoulement plastique à leur extrémité on tente dans l'article de déterminer les conditions de stabilité de telles fissures. Ceci conduit à un critère de fragilité qui se trouve être en bon accord avec le comportement d'un large éventail de matériaux, et qui indique la nécessité d'un module d'élasticité élevé pour atteindre une résistance potentielle élevée.
    Notes: Abstract In most materials, and especially metals, plastic flow occurs at a stress well below the theoretical strength. Cracks in a stressed material can therefore be expected to have a finite width as a result of plastic flow at the tip, and an attempt is made here to determine the conditions for stability of such cracks. This has led to a criterion of brittleness which is in good agreement with the behaviour of a wide range of materials, and indicates that for very high strength materials a large modulus is necessary.
    Type of Medium: Electronic Resource
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