A curvilinear snake arm robot with gripper-axis fibre-optic image processor feedback

The official version of this article can be found at the link below.A curvilinear robot constructed from a number of modular flexible sections of fixed length and diameter but independently controlled radius and direction of curvature has been equipped with an optical fibre image guide transmitting images from between the gripper jaws to the remote TV camera of Microvision-100, a microcomputer controlled real-time DMA-based vision System that is easily trained to recognise the shape, position and orientation of components. The gripper position and orientation is controlled by feedback from the vision System, the action taken depending on component recognition and inspection for defects. Redundant degrees of freedom enable the curvilinear robot to avoid obstacles and work in confined spaces.The research programme described in this paper is supported by the U.K. Science and Engineering Research Council

Professionalism, prejudice and personal taste: does it matter what we wear?

An earlier opinion piece considered the professional issues surrounding the occupational therapist’s dress code within the work place (Davys et al, 2006). This second paper considers the role of the occupational therapist when a client choice of clothing may conflict with social expectations and negatively impact upon social inclusion. Three practice based scenarios are presented, which serve as the prompts for reflection upon informed choice, professional responsibilities and the therapeutic relationship. This paper concludes that there needs to be debate about the conflict between each of these areas and the concept of social inclusion

A high-accuracy optical linear algebra processor for finite element applications

Optical linear processors are computationally efficient computers for solving matrix-matrix and matrix-vector oriented problems. Optical system errors limit their dynamic range to 30-40 dB, which limits their accuray to 9-12 bits. Large problems, such as the finite element problem in structural mechanics (with tens or hundreds of thousands of variables) which can exploit the speed of optical processors, require the 32 bit accuracy obtainable from digital machines. To obtain this required 32 bit accuracy with an optical processor, the data can be digitally encoded, thereby reducing the dynamic range requirements of the optical system (i.e., decreasing the effect of optical errors on the data) while providing increased accuracy. This report describes a new digitally encoded optical linear algebra processor architecture for solving finite element and banded matrix-vector problems. A linear static plate bending case study is described which quantities the processor requirements. Multiplication by digital convolution is explained, and the digitally encoded optical processor architecture is advanced

Nonlinear dynamics of attractive magnetic bearings

The nonlinear dynamics of a ferromagnetic shaft suspended by the force of attraction of 1, 2, or 4 independent electromagnets is presented. Each model includes a state variable feedback controller which has been designed using the pole placement method. The constitutive relationships for the magnets are derived analytically from magnetic circuit theory, and the effects of induced eddy currents due to the rotation of the journal are included using Maxwell's field relations. A rotor suspended by four electro-magnets with closed loop feedback is shown to have nine equilibrium points within the bearing clearance space. As the rotor spin speed increases, the system is shown to pass through a Hopf bifurcation (a flutter instability). Using center manifold theory, this bifurcation can be shown to be of the subcritical type, indicating an unstable limit cycle below the critical speed. The bearing is very sensitive to initial conditions, and the equilibrium position is easily upset by transient excitation. The results are confirmed by numerical simulation

A constitutive model for the forces of a magnetic bearing including eddy currents

A multiple magnet bearing can be developed from N individual electromagnets. The constitutive relationships for a single magnet in such a bearing is presented. Analytical expressions are developed for a magnet with poles arranged circumferencially. Maxwell's field equations are used so the model easily includes the effects of induced eddy currents due to the rotation of the journal. Eddy currents must be included in any dynamic model because they are the only speed dependent parameter and may lead to a critical speed for the bearing. The model is applicable to bearings using attraction or repulsion

A study of the enzymatic hydrolysis of fish frames using model systems

A model system was employed to study the operating conditions and primary parameters of enzymic hydrolysis of cod proteins. Pancreatin, papain, and bromelain were used to hydrolyse minced cod fillets under controlled conditions and with the rate of hydrolysis being continually monitored via both the pH-stat and TNBS method. The two methods were compared and evaluated. The rate of protein solubilisation was plotted against the degree of hydrolysis (DH). Dry fish protein hydrolysate (FPH) powders having short, medium and high degrees of hydrolysis (DH of approximately 8%, 11% and 16% respectively) were produced and analysed for their molecular weight distribution, using size exclusion chromatography. Almost complete protein solubilisation (75 g soluble protein per kg hydrolysis solution) could be achieved within an hour, at 40°C, at 1% enzyme/substrate ratio (w/w) with papain and bromelain. The pH-stat was found capable of continuously following the rate of hydrolysis but only at low DH. The TNBS could be accurately used even at high DH to estimate the percentage of the peptide bonds cleaved, but required chemical analysis of withdrawn samples

Enzymatic hydrolysis of fish frames using pilot plant scale systems

Papain was used to hydrolyse fish frames under controlled conditions at a batch-pilot plant scale-process, for the pro-duction of fish protein hydrolysates (FPH). Mass balance calculations were carried out so that the rate of hydrolysis, rate of protein solubilisation and yields could be estimated. Almost complete hydrolysis could be achieved in 1 hour, at 40°C, with no pH adjustment, at 0.5% (5 g·kg−1) enzyme to substrate ratio (E/S, were S is Kjeldahl protein) using whole fish frames (including heads and flaps). This was achieved both with the addition of water (1/1 to 2/1 frames/water) but more importantly from commercial considerations without the initial addition of water (after mincing of the fish mate-rial). The degree of protein solubilisation ranged between 71% - 86% w/w. Four different processes are described, namely: 1) a soluble spray-dried FPH powder; 2) a liquid FPH; 3) a partly soluble, spray dried FPH powder and; 4) a crude, drum-dried protein for animal consumption. The amino acid profile of the FPH was identical to that of the par-ent substrate (fish frames)