Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

A negative isotropic magnetoresistance effect more than three orders of magnitude larger than the typical giant magnetoresistance of some superlattice films has been observed in thin oxide films of perovskite-like La0.67Ca0.33MnOx. Epitaxial films that are grown on LaAIO3 substrates by laser ablation and suitably heat treated exhibit magnetoresistance values as high as 127,000 percent near 77 kelvin and ∼1300 percent near room temperature. Such a phenomenon could be useful for various magnetic and electric device applications if the observed effects of material processing are optimized. Possible mechanisms for the observed effect are discussed.

http://science.sciencemag.org/content/sci/264/5157/413.full.pdf

Thousandfold Change in Resistivity in Magnetoresistive La-Ca-Mn-O Films

The Theory of Matrices. By F R. Gantmacher. Two volumes, pp. 374 and 276. 1959. (Translated from the Russian by K. A. Hirsch; Chelsea Publishing Company, New York)

Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B

Fluids of differential type: Critical review and thermodynamic analysis

Commercially pure titanium was sandblasted with SiO2 particles of 200–300 μm in diameter. It was found that the sandblasted samples exhibited an increase in fatigue strength by 11% over that of the untreated samples. The peak subsurface compressive residual stress produced by sandblasting was measured by XRD to be around 480 MPa. Three distinct regions were observed in the sandblasted samples, namely the severely deformed surface layer, the region deformed mainly by twinning, and the substrate. After recovery treatment below 300 °C, the surface layer of the sandblasted samples was transformed into a nano-crystalline structure, and its corrosion resistance was significantly improved.

Enhancement of fatigue and corrosion properties of pure Ti by sandblasting

The rudiments of an acoustoelastic theory is developed within the framework of linear elasticity with initial stress. Since no assumption is made about the origin of the initial stress, our acoustoelastic theory will be applicable to evaluation of stress in plastically deformed bodies, provided that the superimposed ultrasonic waves be hyperelastic. New universal relations are deduced. An approach to evaluation of stress which does not use calibration specimens and makes full use of universal relations in our acoustoelastic theory is advocated. Examples are given which illustrate application of our theory to evaluate residual stress in plates. Preliminary corroborations of our theory are provided by the recent experiments of King & Fortunko and Thompson et al.

/pdf/towards-an-acoustoelastic-theory-for-measurement-of-residual-1qi51xr71a.pdf

Towards an acoustoelastic theory for measurement of residual stress

The application of shot-peening to improve performance and reduce scatter in the high cycle fatigue regime is common in aerospace production practice. Frequently, aerospace components are re-shot-peened during refit to “restore” compressive stresses that may have redistributed in service. Since shot-peening is an impact process that can cause various surface artifacts, it is not clear what effect this re-shot-peening process has on fatigue properties. In the current study, the effects of shot-peening and re-shot-peening on the profile of surface residual stress and the four-point bend fatigue behavior of Ti–6Al–4V(wt.%) alloy were investigated at room temperature and 150 °C. A step-test method was used to determine the fatigue strength of the shot-peened and re-shot-peened specimens in different conditions. Shot-peening improved the fatigue strength of the alloy from about 65% σ y to 71% σ y ( σ y is the yield strength of this alloy at room temperature). The fatigue limits of the shot-peened Ti–6Al–4V alloy at room temperature and 150 °C were found to be almost identical. Residual stresses did not seem to redistribute significantly under the fatigue loading at room temperature and 150 °C. Both shot-peening and re-shot-peening significantly enhanced the fatigue strength over that of the un-shot-peened alloy. No negative effects of re-shot-peening were observed.

Effects of shot-peening and re-shot-peening on four-point bend fatigue behavior of Ti–6Al–4V

McTigue and others (1985) identified a possible problem in the type of constitutive equation usually used for modeling the creep behaviour of polycrystalline ice. They pointed out that Glen’s flow law necessarily excludes the consideration of normal stress effects, which are of great significance in other disciplines that consider non-Newtonian fluids. Using the second-order fluid (with material parameters evaluated from laboratory data) as a tentative model for ice, they reached the conclusion that normal stress effects may be discernible in natural glacier flow. But, as noted by McTigue and others, the second-order fluid “fails to represent the non-linear rate dependence of ice in shear”; therefore it is in fact not a suitable constitutive model for glacier ice in shearing flow. In this note, parallel to what McTigue and others did for the second-order fluid, we present a similar analysis for (I) the modified second-order fluid and (II) the power-law fluid of grade 2, both of which are constitutive models recently proposed by Man as a tentative generalization of Glen’s flow law. Both models (I) and (II) can represent normal stress effects, and both agree with Glen’s flow law in the prediction of the depth profile of velocity in the steady laminar flow of glaciers. For ease of comparison, the same creep data of McTigue and others are used in quantifying the material parameters in these two models. Both models (I) and (II) predict far less pronounced normal stress effects in glaciers than those estimated by McTigue and others (whose data analysis in fact suffered from inconsistencies and over-parameterization).

/pdf/on-the-significance-of-normal-stress-effects-in-the-flow-of-1fx94dmtb2.pdf

On the Significance of Normal Stress Effects in the Flow of Glaciers

The two constitutive equations which have hitherto been called upon in mathematical studies on static determination of residual stress by boundary measurements share the same deficiency, namely that they do not adequately describe the elastic response of any currently known real material. Here we substantiate this critical remark and present a physically more acceptable constitutive equation for further work on the subject.

https://iopscience.iop.org/article/10.1088/0266-5611/14/2/007/pdf

Chi-Sing Man

Papers

Enhancement of fatigue and corrosion properties of pure Ti by sandblasting

Towards an acoustoelastic theory for measurement of residual stress

Effects of shot-peening and re-shot-peening on four-point bend fatigue behavior of Ti–6Al–4V

On the Significance of Normal Stress Effects in the Flow of Glaciers

Hartig's law and linear elasticity with initial stress