Showing papers by "Ford Motor Company published in 1970"

Empirical Relation between the Linear and the Third-Order Nonlinear Optical Susceptibilities

Abstract: A simple empirical relation is found to exist between the linear and the third-order nonlinear optical susceptibilities This empirical relation holds within the available experimental accuracy for gases at low pressures The applicability of this empirical relation to crystalline solids, and its bearing on the generalized Miller's rule for these solids, are discussed

Statistical detection for communication channels with intersymbol interference

Abstract: The optimum detector under a fixed delay constraint D is derived for channels having memory and additive noise. The resulting receiver is recursive and does not grow with the message length. Its structure is presented for linear channels (AM and PSK) with known (or estimated) impulse response and noise statistics. The intersymbol interference is assumed to extend for L sampling periods and the receiver is allowed a "look-ahead" at D future received samples. Simulation results using actual channel characteristics show the detector to outperform a transversal equalizer even for relatively small values of D.

Spectral Broadening of Elastic Second-Harmonic Light Scattering in Liquids

Abstract: The spectral width of "elastic" second-harmonic light scattering has been measured for a number of liquids. The broadening arises principally from rotational molecular motions and, ignoring possible nonadditive molecule-molecule interactions, the spectrum is shown to be related to the Fourier transform of the orientation-dependent pair distribution function $G(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}}, \stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Omega}}, t)$. An irreducible spherical-tensor representation is employed. It is shown that a totally symmetric nonlinear-susceptibility tensor produces elastic harmonic light scattering characterized by just the first- and third-degree spherical elements of $G(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}}, \stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Omega}}, t)$ and that the corresponding spectra may be independently determined. For Brownian orientational motion, these comprise Lorentzians whose widths are related to the tensorial orientational-diffusion coefficient. For isotropic orientational diffusion, the widths are in the ratio 1: 6. Dielectric-relaxation and depolarized Rayleigh scattering also relate to $G(\stackrel{\ensuremath{\rightarrow}}{\mathrm{r}}, \stackrel{\ensuremath{\rightarrow}}{\ensuremath{\Omega}}, t)$, and the results of all three experiments are compared. In no instance was isotropic orientational diffusion found to be a satisfactory model. A more extended study was made of carbon tetrachloride. Evidence was found both for nonadditive response and for coherent effects resulting from short-range orientational ordering. The extremely weak signals - often less than one photoevent per laser firing - necessitated development of a reliable high-repetition-rate $Q$-switched ruby laser and use of electronic data-accumulation techniques.

Chemistry of the collagen cross-links. Isolation and characterization of two intermediate intermolecular cross-links in collagen

Abstract: This paper describes the isolation from reduced collagen of two new amino acids believed to be involved, in their non-reduced form, as intermolecular cross-links stabilizing the collagen fibre. The reduction of intact collagen fibrils with tritiated sodium borohydride was found to stabilize the aldehyde-mediated cross-links to acid hydrolysis and thus allowed their location and isolation from acid hydrolysates on an automatic amino acid analyser. Comparison of the radioactive elution patterns from the autoanalyser of collagen treated in various ways before reduction permitted a preliminary classification of the peaks into cross-link precursors, intramolecular and intermolecular cross-links. The techniques employed to isolate the purified components on a large scale and to identify them structurally are described in detail. Two labile intermolecular cross-links were isolated in their reduced forms, one of which was identified by high-resolution mass spectrometry as N(in)-(5-amino-5-carboxypentyl)hydroxylysine. The structure of this compound was confirmed by chemical synthesis. The cross-link precursor alpha-aminoadipic delta-semialdehyde was isolated in its reduced form, in-hydroxynorleucine, together with its acid degradation product in-chloronorleucine. A relatively stable intermolecular cross-link was isolated and partially characterized by mass spectrometry as an aldol resulting from the reaction of the delta-semialdehyde derived from lysine and hydroxylysine.

Stress and Volume Relaxation in Annealing Flat Glass

Abstract: Laboratory simulation of the industrial process of annealing sheet glass has yielded data on the genesis of stresses in initially stress-free glass. The experimental results differed from expectations based on classical annealing theory in that stresses began to develop in the annealing range even when the glass was being cooled at a constant rate, i.e. even in the absence of any changes of temperature gradients within the glass. Typically, these stresses account for 40% of the total residual stress in glass annealed according to a linear schedule. The remaining 60% are the well-known thermoelastic stresses that arise later in the annealing process from the decay of temperature gradients in the glass. The stresses observed to arise in glass as it is being cooled at a constant rate are attributed to volume relaxation effects which, in parts of the annealing range, generate stresses rapidly enough that they are not dissipated by stress relaxation. A mathematical model of annealing is proposed that takes account of both stress and structural relaxation. The model fits the experimentally observed evolution of stresses during linear cooling. It also suggests that (with the activation energies of stress and structural relaxation about the same) the actual rate, at any given temperature, of structural relaxation is about 4 times lower than that of stress relaxation.

Determination of stress-strain characteristics at very high strain rates

Abstract: A modified version of the Kolsky thin-wafer technique is described. The method permits one to obtain the dynamic plastic properties of materials at strain rates as high as 105 sec−1. Data obtained from compression tests on high-purity aluminum are presented for strain rates ranging from 4000 to 120,000 sec−1 at room temperature. Specimen-size effects and the effect of lateral inertia are taken into account in analyzing the data. The results plotted as stress vs. strain rate at constant strains (5 to 20 percent) show that, at the highest strain rates, the stress rises very rapidly with strain rate suggesting that a limiting strain rate is being reached. At the lower strain rates (103 to 104 sec−1), the stress is linearly proportional to the strain rate indicating that the material is deforming in a viscous manner.

Resonance Raman Scattering of Laser Radiation by Vibrational Modes of Carotenoid Pigment Molecules in Intact Plant Tissues

Abstract: WE report here the detection of resonance Raman (RR)1–11 scattering of laser radiation from vibrational modes in the molecules of the carotenoid pigments12–14 lycopene and β-carotene in intact plant samples (Figs. 1a and b). Resonance enhancement is obtained in the Raman spectra of pigments excited at wavelengths in the region of electronic absorption. The effect is manifest in a conspicuous gain in the scattering efficiency from some of the vibrational modes of the pigment. The scattered light becomes sufficiently intense to overcome the increased absorption losses of both the exciting and the scattered radiation. In this study we have demonstrated this effect in heterogeneous (tissue) samples, in which the pigment is just one constituent.

Second Paper: Instantaneous Heat Transfer Rates to the Cylinder Head Surface of a Small Compression-Ignition Engine:

Abstract: Measurements of instantaneous heat transfer rates from the working fluid to the cylinder head of a small open-chamber, four-stroke, compression-ignition engine have been made at five points on the surface, using a new form of thin-film thermocouple. These observations demonstrate that flux magnitude and the form of flux variation during the cycle depend greatly on local conditions. Some of the observed phenomena are explained qualitatively. Finally, some results are presented of an analysis of fluxes averaged over all five locations, in terms of the bulk mean properties of the working fluid. It is shown that some compensation for the non-steady nature of the situation may be given by adding to the usual type of quasi-steady relation a term involving the time derivative of the bulk mean temperature.

Voltage-Induced Vorticity and Optical Focusing in Liquid Crystals

Abstract: We have observed that liquid crystals of the $p$-azoxyanisole type exhibit macroscopic rotational motion above a threshold voltage. The vortex motion of the birefringent liquid results in a lattice of cylindrical lenses whose focal lengths are voltage variable. These experiments are in excellent agreement with the dynamic predictions of the continuum theory.

Load-compression behavior of brittle foams

Abstract: Quantitative relationships between the load-compression behavior and the physical characteristics of the foam matrix, previously reported for flexible systems, have now been extended to brittle foams. The shape of the compression curve is expressed in terms of ψ(e), a dimensionless function of the compressive strain, while the stiffness, or load-bearing capacity, is defined by Ef, the apparent Young's modulus. Because the brittle matrix breaks–rather than flexes–when compressed, a brittle foam exhibits a flatter and wider plateau in the load-compression curve than a rigid (but ductile) foam of equivalent density, cell geometry, and Ef. These differences are expressed quantitatively by ψ(e). It is important to distinguish between brittle foams and rigid, but ductile, foams. Since both types may exhibit the same stiffness, this distinction, particularly significant in energy absorbing applications, often is not considered in designing foam structures. Using the relationships established in this report, it is now possible to delineate precisely the characteristics a brittle foam must possess to meet a given load-compression specification.

The Meyerhof quotient and the synthesis of glycogen from lactate in frog and rabbit muscle. A reinvestigation

Abstract: 1. The conversion of lactate into glycogen was demonstrated in frog sartorius muscle in oxygen. The rates and amounts are highest when lactate is added to the bathing medium and are dependent on lactate and CO(2) concentration, as well as pH. The glycogen content of a resting muscle can be doubled in 4h at 24 degrees C. 2. Sartorius muscle, recovering aerobically in liquid paraffin from a period of anoxia, converts preformed lactate into glycogen at a lower rate and in smaller amounts than when lactate is added in an aqueous medium. The lower rates are similar to those Meyerhof found under the same conditions, after correction for temperature; they can be attributed partly to low muscle pH and partly to the limited amounts of lactate present. 3. Rabbit psoas muscle also shows the ability to convert added lactate into glycogen under aerobic conditions. The rates are low and similar to those in frog sartorius muscle recovering from anoxia. 4. The present experiments yield a Meyerhof quotient of 6.2, compared with Meyerhof's value of 4-5. However, these values are not significantly different from one another. 5. It is suggested that the glycogen coefficient, i.e. mol of glycogen formed/mol of lactate disappearing, is a more reliable way of assessing the resynthetic mechanism than the original quotient, i.e. mol of lactate disappearing/mol of lactate oxidized. The found coefficient is 0.419+/-0.024.

Grain size effects in the strain hardening of polycrystals

Abstract: The degree to which the flow stress of a polycrystal is sensitive to grain size is discussed in terms of the distribution of slip and dislocation structure that develops in the vicinity of grain boundaries as deformation proceeds. The point of view is taken that the two principal classes of grain boundary hardening models, namely, those based on dislocation pile-ups and those based on dislocation density concepts respectively represent special cases of a single rationale developed in this paper. Grain boundary strengthening is intimately related to strain hardening which is affected by slip mode,i.e., the number of slip systems and the ability to cross slip. The effects of substitutional solute elements on grain boundary strengthenings is considered to be a consequence of their influence on slip modes rather than on their interaction with dislocation sources.

Energy‐absorbing characteristics of foamed polymers

Abstract: The energy-absorbing characteristics of a foam are determined by its load–compression response, and hence reflect the geometric structure and physical properties of the matrix material. In this report, the energy-absorbing characteristics are expressed in terms of three dimensionless quantities: (1) K, the energy-absorbing efficiency, (2) I, the impact energy per unit volume divided by Ef, and (3) I/K, the maximum decelerating force per unit area divided by Ef, where Ef is the apparent Young's modulus. Using the calculation procedures described in this report, it is now possible to delineate the geometric structure and physical properties a foam matrix must possess to meet a given energy absorption specification. This approach shows that: (1) the energy-absorbing characteristics of a brittle foam are superior to those of a ductile foam, (2) the optimum energy-absorbing foam has a large cell size, a narrow cell size distribution, and a minimum number of reinforcing membranes between the cells, (3) foam composites offer no significant advantage over a single foam, and (4) the optimum energy-absorbing region obtains over a tenfold change in impact velocity and can be extended in a given system only if the foam stiffness increases while the impact velocity is increased, as in a fluidfilled foam.

The use of young’s modulus for predicting the plastic-strain ratio of low-carbon steel sheets

Abstract: The variation in Young’s modulus,E, and plastic-strain ratio,R, with angle to the rolling direction, o, was measured for 35 samples of cold-rolled and annealed low carbon steel sheets. Functions ofE andR were fitted to an empirical expression and correlations were made from which it was possible to predict not only the average plastic-strain ratio, −R, but also the planar anisotropy, ΔR, and the dependence ofR on o Calculations were made of the orientation dependence ofE and the quantity R/(R + 1) for single crystals of α-Fe. Although these calculations show that the correlations made for polycrystalline samples are reasonable, they offer little guidance as to the probable limits of applicability of the correlations. The limiting drawing ratio (LDR) was determined_for 12 sheet samples by Swift-cup testing. For these limited results, the average modulus, −E, and the average strain ratio, −R, correlate equally well with the LDR. Use of E(o), to predict deep drawability and earing, should reduce the effort required to characterize the formability of. low-carbon steel sheets.

Flexible check valves

Abstract: Check valve apparatus for controlling fluid flow, comprising a flexible ''''flapper'''' -type valve member and a tubular valvereceiving collar including an internal annular valve seat. The collar is apertured around a portion of its periphery to accommodate insertion of the flexible valve laterally of the direction of fluid flow. Mounting of a hose over the collar, and clamping of the hose thereon, provides a seal and completes the assembly.

The temperature dependence of the flow stress of the γ' phase based upon Ni 3 Al

Abstract: The temperature dependence of the ordinary flow stress, the microplastic yield stress, and the transient creep responses ofγ′ have been studied with respect to the effect of alloying additions, slip line topography, and dislocation structure. The increase observed in the flow stress with increase in temperature may be attributed to a change in the mechanism controlling the flow stress. An exhaustion hardening process at low temperatures appears to be supplanted by a debris hardening process at high temperatures. This transition arises from an increased propensity for {100} slip as the temperature is raised. Solute additions affect the temperature dependence of the flow stress probably by altering the tendency for {100} slip.

Forced velocity pearlite

Abstract: A high purity Fe-C alloy of eutectoid composition has been transformed from homogenized austenite in two ways: isothermally and at forced constant-velocity. The latter transformation mode, forced over five decades of velocity, produces structures with characteristic dimensions ranging over nearly two orders of magnitude. There is a consistent alignment of the transformation product in the heat-flow direction at all velocities, but the classical pearlite morphology undergoes a microstructural transition at the higher velocities. A spacing-velocity relationship for regular lamellar pearlite was measured as V0.41±o.02λν = constant.