The Microstructure of the Hen\u27s Egg Shell - A Short Review

The structure of the hen\u27s egg shell can be divided into five separate layers . The Innermost layer consists of two distinct membranes known as the inner and outer shell membranes. These membranes are compos ed of networks of protein/polysaccharide fibres and are =70 mm thick. Attached to the outer fibres of the outer membrane are polycrystals of calcite (calcium carbonate) which extend outward in an inverse conical manner until the cones from several sites of crystal i nit iation fuse together. The fibre/ crystal attachment sites, known as basal caps, and the cones form the mammillary knobs layer which is :: 100- 110 llm thick. After the cones fuse with each other, continuing calcite deposition produces columnar crystals 10 -30 \u27m in diameter and :::200 llm in length. These crys tals form the palisade layer and are intermingled with a protein/polysaccharide matrix that differs in composition From the shell membranes. Over the columnar crystals is a thin layer (::S -8 \u27m thick), known as the vertical crystal layer, of small calcite crystals that are orientated perpendicular to the shell\u27s surface. The cuticle is the outermost layer of the shell; it is =10 mm thick and contains predominantly protein. Passing vertically through the palisade layer of the shell from valleys between the marrmillary knobs to the surface of the vertical crystal layer are funnel - shaped, unbranched pores, These pores are capped by the cuticle which is cracked and thus allows the diffusion of gases between the contents of the egg and its environment. The geometrical configuration of the cones in the mammillary knobs layer is related to the thickness of shell. Specific amino acids in the membrane fibres

The Microstructure of the Hen\u27s Egg Shell - A Short Review

The structure of the hen\u27s egg shell can be divided into five separate layers . The Innermost layer consists of two distinct membranes known as the inner and outer shell membranes. These membranes are compos ed of networks of protein/polysaccharide fibres and are =70 mm thick. Attached to the outer fibres of the outer membrane are polycrystals of calcite (calcium carbonate) which extend outward in an inverse conical manner until the cones from several sites of crystal i nit iation fuse together. The fibre/ crystal attachment sites, known as basal caps, and the cones form the mammillary knobs layer which is :: 100- 110 llm thick. After the cones fuse with each other, continuing calcite deposition produces columnar crystals 10 -30 \u27m in diameter and :::200 llm in length. These crys tals form the palisade layer and are intermingled with a protein/polysaccharide matrix that differs in composition From the shell membranes. Over the columnar crystals is a thin layer (::S -8 \u27m thick), known as the vertical crystal layer, of small calcite crystals that are orientated perpendicular to the shell\u27s surface. The cuticle is the outermost layer of the shell; it is =10 mm thick and contains predominantly protein. Passing vertically through the palisade layer of the shell from valleys between the marrmillary knobs to the surface of the vertical crystal layer are funnel - shaped, unbranched pores, These pores are capped by the cuticle which is cracked and thus allows the diffusion of gases between the contents of the egg and its environment. The geometrical configuration of the cones in the mammillary knobs layer is related to the thickness of shell. Specific amino acids in the membrane fibres

Sonobuoy Mils

The purpose of this paper is to describe a new technique for locating missile impact positions in the open ocean using Navy sonobuoys. Figure 1 shows a typical Navy ASW sonobuoy, an air-dropped, expendable VHF radio that relays the underwater acoustic signals received on a hydrophone beneath it to an aircraft overhead* This missile impact location system has the advantages of being low cost, portable and capable of high accuracy. Basically the sonobuoys monitor the hydroacoustic signal of a missile impact on the ocean\u27s surface and use fixed ocean bottom transponders as a geodetic reference for the sonobuoys* Heretofore we have used aircraft dropped sofar charges as an acoustic tie between the surface sonobuoys and the ocean bottom transponders. Impact accuracy in this sonobuoy system of 0.1 NM is possible. In the future, with a little more hardware development, the use of active sonobuoys will eliminate the need for the sofar charge reference tie and the upgraded SMILS will have an accuracy of 250\u27

The effect of low-energy ion-implantation on the electrical transport properties of Si-SiO2 MOSFETs

Using silicon MOSFETs with thin (5nm) thermally grown SiO2 gate dielectrics, we characterize the density of electrically active traps at low-temperature after 16keV phosphorus ion-implantation through the oxide. We find that, after rapid thermal annealing at 1000oC for 5 seconds, each implanted P ion contributes an additional 0.08 plus/minus 0.03 electrically active traps, whilst no increase in the number of traps is seen for comparable silicon implants. This result shows that the additional traps are ionized P donors, and not damage due to the implantation process. We also find, using the room temperature threshold voltage shift, that the electrical activation of donors at an implant density of 2x10^12 cm^-2 is ~100%.Comment: 11 pages, 10 figure

The Generalized Ricci Flow for 3D Manifolds with One Killing Vector

We consider 3D flow equations inspired by the renormalization group (RG) equations of string theory with a three dimensional target space. By modifying the flow equations to include a U(1) gauge field, and adding carefully chosen De Turck terms, we are able to extend recent 2D results of Bakas to the case of a 3D Riemannian metric with one Killing vector. In particular, we show that the RG flow with De Turck terms can be reduced to two equations: the continual Toda flow solved by Bakas, plus its linearizaton. We find exact solutions which flow to homogeneous but not always isotropic geometries

A compactness theorem for complete Ricci shrinkers

We prove precompactness in an orbifold Cheeger-Gromov sense of complete gradient Ricci shrinkers with a lower bound on their entropy and a local integral Riemann bound. We do not need any pointwise curvature assumptions, volume or diameter bounds. In dimension four, under a technical assumption, we can replace the local integral Riemann bound by an upper bound for the Euler characteristic. The proof relies on a Gauss-Bonnet with cutoff argument.Comment: 28 pages, final version, to appear in GAF

The measurement of lubricant-film thickness using ultrasound

Ultrasound is reflected from a liquid layer between two solid bodies. This reflection depends on the ultrasonic frequency, the acoustic properties of the liquid and solid, and the layer thickness. If the wavelength is much greater than the liquid-layer thickness, then the response is governed by the stiffness of the layer. If the wavelength and layer thickness are similar, then the interaction of ultrasound with the layer is controlled by its resonant behaviour. This stiffness governed response and resonant response can be used to determine the thickness of the liquid layer, if the other parameters are known. In this paper, ultrasound has been developed as a method to determine the thickness of lubricating films in bearing systems. An ultrasonic transducer is positioned on the outside of a bearing shell such that the wave is focused on the lubricant-film layer. The transducer is used to both emit and receive wide-band ultrasonic pulses. For a particular lubricant film, the reflected pulse is processed to give a reflection-coefficient spectrum. The lubricant-film thickness is then obtained from either the layer stiffness or the resonant frequency. The method has been validated using fluid wedges at ambient pressure between flat and curved surfaces. Experiments on the elastohydrodynamic film formed between a sliding ball and a flat surface were performed. Film-thickness values in the range 50-500 nm were recorded, which agreed well with theoretical film-formation predictions. Similar measurements have been made on the oil film between the balls and outer raceway of a deep-groove ball bearing

Remarks on the extension of the Ricci flow

We present two new conditions to extend the Ricci flow on a compact manifold over a finite time, which are improvements of some known extension theorems.Comment: 9 pages, to appear in Journal of Geometric Analysi

Observing sub-microsecond telegraph noise with the radio frequency single electron transistor

Telegraph noise, which originates from the switching of charge between meta-stable trapping sites, becomes increasingly important as device sizes approach the nano-scale. For charge-based quantum computing, this noise may lead to decoherence and loss of read out fidelity. Here we use a radio frequency single electron transistor (rf-SET) to probe the telegraph noise present in a typical semiconductor-based quantum computer architecture. We frequently observe micro-second telegraph noise, which is a strong function of the local electrostatic potential defined by surface gate biases. We present a method for studying telegraph noise using the rf-SET and show results for a charge trap in which the capture and emission of a single electron is controlled by the bias applied to a surface gate.Comment: Accepted for publication in Journal of Applied Physics. Comments always welcome, email [email protected], [email protected]