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The use of portable X-ray fluorescence (PXRF) spectrometry to detect dietary external markers on processed or unprocessed bovine fecal specimens to estimate apparent total tract digestibility (ATTD) was evaluated. Seven beef crossbred, ruminally-cannulated steers (BW = 520 ± 30 kg) were used in a completely randomized design. Steers were individually fed a steam-flaked corn-based finishing diet ad libitum for 21-d. Degradable gel capsules containing 7.5 g of titanium dioxide and chromic oxide were placed inside the rumen through the ruminal-cannulae twice daily, throughout the experiment. Fecal samples were collected twice daily from d 14–21, stored frozen (-20oC), and thawed on d-21 to make a composite sample per steer/day. Wet chemistry analyses of fecal samples included atomic absorption for Cr and spectrophotometry for TiO2 and were compared with PXRF to determine the concentration of these markers on three types of fecal specimens: fresh (average 22.5 % DM), dried (60oC, 72 h), or dried/ground (1 mm). Data were analyzed using the GLIMMIX procedures of SAS with collection day as a repeated measure. Delta between ATTD estimated by wet chemistry and PXRF was not different from zero when using fresh fecal specimens analyzed for Cr (P = 0.40) or Ti (P = 0.14), while for dried or dried/ground specimens it differed (P ≤ 0.04), in which ATTD was underestimated by 3.6 and 1.1 percent units for Cr and Ti, respectively, when using PXRF. Concentration of Ti in fecal specimens was similar (P = 0.39) between analytical methodologies regardless of sample preparation. However, concentration of Cr was underestimated (P < 0.01) by 13% when PXRF was used in dried or dried/ground fecal samples compared to wet chemistry. Detection of Cr and Ti in fresh fecal samples with PXRF spectrometry seems to be a viable alternative to wet chemistry for estimating ATTD for finishing steers.

The scattering at a rectilinear step change in depth of a shallow-water vortex pair consisting of two patches of equal but opposite-signed vorticity is studied. Using the constants of motion, an explicit relationship is derived relating the angle of incidence to the refracted angle after crossing. A pair colliding with a step from deep water crosses the escarpment and subsequently propagates in shallow water refracted towards the normal to the escarpment. A pair colliding with a step from shallow water either crosses and propagates in deep water refracted away from the normal or, does not cross the step and is instead totally internally reflected by the escarpment. For large depth changes, numerical computations show that the coherence of the vortex pair is lost on encountering the escarpment.

The paper outlines a modelling technique that predicts how woven fabric constructions will change shape when subjected to the application of hydrostatic pressure. The initial specification required for the technique is in terms of a triangulated pattern for each fabric piece in the construction and an initial 3D location for each node. Fabric types are characterised by look-up tables describing the warp and weft tensile and shear behaviours. The modelling proceeds by seeking to find the minimum energy state of the construction where material strain energy is balanced by the energy required to inflate the construction by the application of hydrostatic energy. Examples are provided to illustrate the operation of the technique.

With traditional two-dimensional based interfaces, many CAD surface models are difficult to design and edit due to their 3D nature. This paper discusses a technique for the deformation of CAD surface models with haptic interaction based on shape control functions. With the technique, designers can use a haptic interface to directly touch a native B-rep CAD model, and deform it in real-time by pushing, pulling and dragging its surfaces in a natural 3D environment. The deformation is governed by shape control functions. By using the shape functions, designers can specify the area of deformation, and also have greater controls on the shape of deformation. This technique is numerically efficient, and can deform complex surface models involving several thousand control points in real-time. The haptic-based deforming approach gives designers greater flexibility for the manipulation of complex CAD surfaces.

In many applications it is necessary to define good-fitting 2D flattened patterns for user-defined regions of a larger 3D surface. This paper describes the major stages involved in pattern flattening and illustrates the process with examples. In generating 2D patterns, some distortion is inevitably involved if the target 3D surface is not developable. For situations where distortion is required, it can be quantified in terms of the energy that must be imparted to the 2D flattening in localised areas so that it takes-up the original 3D region of the surface. An orthotropic strain model is adopted to convert the strain values to energy values. Starting with a bi-parametric definition of a large 3D surface, an arbitrary defined region is specified by the user in terms of a contiguous series of cubic curves lying on the bi-parametric plane. To extract the 3D region, a polygon list is generated to represent the surface. The triangulation process is based on a 'marching front' algorithm. A process is described which then flattens this polygon list and performs an energy minimisation analysis every time the process attempts to flatten an over-constrained triangle. Further consideration is made of seam insertion in the 3D surface definition and of adaptively modifying the triangulation process so that more triangles are used in areas of high-energy concentration. Examples are also presented to illustrate the sensitivity of the strain profiles to the fabric grain direction when the pattern is applied to the 3D surface.

In this paper, a model for predicting the stresses within a strained anisotropic fabric is presented. The fabric is characterised by tensile test data in the warp and weft directions as well as shear behaviour. The data is in the form of look-up tables that are capable of representing the non-linear form of each response. The model operates simultaneously on a triangular representation for both the 2D pattern defined on an undistorted fabric and an equivalent triangulation of a 3D representation of the fabric. An energy relaxation technique is applied to the situation in order to predict how the 3D representation should react in order to reach a minimum energy state. Arbitrary constraining configurations can be applied by setting a flag for each node to indicate those fixed in 3D. The resultant forces on fixed nodes can be determined. The model has been successfully applied to two examples. In the second of these, validation took the form of measuring the physical force effects of the fabric on an experimental rig and comparing them with those predicted by the model. It was then demonstrated that the model could predict other forces that could not be easily measured.

Haptic devices (force feedback interfaces) show great promise for use in the design of CAD models. However, current haptic systems are used primarily to verify rather than to interact with CAD systems to design a model. The paper discusses a haptic-based CAD system—Virtual DesignWorks. It is the world's first haptic application for the design of CAD models based on component technology (COM+). With haptic devices, the system allows engineers, in virtual space, to directly touch a native B-Rep CAD model, and deform it by pushing, pulling and dragging its surfaces in a natural three-dimensional environment. Virtual DesignWorks adopts the novel COM-based haptic model, which demonstrates significant advantages compared to the traditional haptic models. Force feedback gives designers the greatest flexibility for the design of complex surfaces, and haptics has the potential to become a critical interface for design applications.

Machining with an uneven chip load can lead to dimensional errors on workpiece surfaces. Tool deflections are liable to occur especially when machining with slender end mills where tool flexibility is high compared with that of the machine structure. Whilst steady state machining errors are commonly considered, it is more difficult to deal with the transient errors that occur at tool entry and exit to cuts. Using a predictive equation that links tool deflection to chip load, it is possible to compare expected errors of form or position with standards set out using geometric dimensioning and tolerancing. Machining conditions can be investigated to establish whether part features can be manufactured within tolerances allowed. A process for selecting machining conditions for producing a circular pocket is introduced. The use of a tolerance analysis chart is demonstrated to clarify the results of machining at tool entry and exit.

This paper presents prevalence data from the 1994 OPCS survey of psychiatric morbidity among adults permanently resident in institutions catering for people with mental health problems in Great Britain. It describes briefly the survey methods used, and how diagnoses of psychiatric morbidity were derived. Its main aim is to show the prevalence of psychiatric morbidity in different types of institutional settings. Residents were eligible for the survey if they were aged 16 to 64 at the date of sampling and were permanently resident at the establishment. Residents were defined as permanently resident if they had been living in the sampled establishment for six months or more, or had no other permanent address, or were likely to stay in the establishment for the foreseeable future. In 1994, about 33,200 adults aged 16 to 64 were permanently resident in accommodation for people with mental health problems. About a third of residents were in NHS hospitals, while about two-thirds were in residential care facilities. About two-thirds of adults interviewed suffered from schizophrenia, delusional and schizoaffective disorders. About 8% suffered from neurotic disorders and 8% suffered from affective psychoses (mainly bipolar affective disorder). The prevalence of schizophrenia, delusional, and schizoaffective disorders was higher in hospitals than in residential care, while the prevalence of neurotic and related disorders was higher in residential accommodation. The prevalence of schizophrenia, delusional, and schizoaffective disorders was higher in NHS psychiatric hospitals and general hospital units than in private hospitals, clinics or nursing homes.

The word retirement is going out of fashion. Many orthopaedic surgeons want to work in some capacity when they stop performing surgery. Making a smooth transition from a busy orthopaedic practice to alternative work demands advanced planning. The surgeon must consider personal issues that involve how to use human capital (his or her accumulated knowledge and experience). New ventures, hobbies, travel, and spending time with family and friends are some possibilities. Plans for slowing down or leaving the practice should be discussed and agreed on well ahead of time. Agreements for buyouts may be difficult to work out and will require creative thinking. The solo practitioner can close the practice or hire a successor. Financial planning is perhaps the most important consideration and should be started by approximately age 40. It is recommended that the surgeon develop a portfolio of secure investments and annuities to provide adequate income for as long as is needed and then to turn the residual income to one's family, favorite charities, or other desired cause. A team of competent advisors is needed to help develop and achieve one's goals, create financial security, and provide the discipline to carry out the needed planning for life after orthopaedics.

The requirements in CAD modelling of garments are first considered and alternative user interfaces are considered. Features which occur in block patterns and for which accurate simulation is required are identified. An energy based modeller, developed for drape simulation, is introduced and applied to model garment constructional details in fabric test specimens of variable stiffness. The modeller is further applied to garment pieces in contact with a mannequin to compare drape with and without constructional features.

While considerable progress has been made in fabric modelling techniques, which could be used in garment computer aided design (CAD) systems, less attention has been paid to the way in which garments might be specified in a CAD system. The final shape taken by a garment is often achieved through the incorporation of darts, seams, edges, stiffening pads and local stretch of the fabric. In order to gain credibility, CAD systems should have to functionally handle the level of complexity normally found in garment assemblies combined with a simple interface to specify the constructional detail. Different conceptual approaches are possible. Given an accurate drape algorithm, garment block patterns in a chosen fabric could simply be anchored or attached around the mannequin in order to achieve a visualisation of a garment. If changes were necessary, the user would alter the 2D patterns and re-run the visualisation. An alternative and possibly more productive approach would be to specify in 3D, with advanced drawing tools, the 3D shape required. Processing of the 3D garment piece using expert rules would indicate the 2D shape and constructional detail required to achieve the final form. This paper describes a CAD system that is under development and which aims to facilitate both the approaches.

Applications such as garment manufacture and composite structure fabrication require a two dimensional (2D) woven material to assume a three dimensional (3D) shape. The specification of the process is usually initiated by defining the 3D surface. Hence, the problem arises of determining the best 2D pattern. The problem is made more complex by the anistropic nature of woven fabrics which are often used as raw material. Such materials display a variation in mechanical properties with respect to the woven structure. This paper presents a model for determining the optimum 2D pattern for a specified 3D surface where optimality is determined in terms of minimising the energy distribution required to force the 2D pattern to assume the 3D shape. The 3D surface specification is assumed to consist of a polygonal mesh. The model allows affine transformations to be applied to the weave structure which can be unique for each polygon in the mesh. Important considerations in the modelling process include the following: 1. The degree to which the specified 3D surface departs from a developable surface. 2. The energy components used to model the woven structure and their sensitivity to weave direction. Essentially, these stem from tensile strain in each direction of the weave and shear strain. 3. The prediction of weave geometry as it reacts to the energy distribution being applied. The model is demonstrated by applying it to a relatively simple pyramidal 3D shape. Energy values are optimised to produce a pattern that requires the minimum overall energy to be applied to the 2D pattern in order for it to assume the 3D shape. This 2D pattern is sensitive to the orientation of the woven structure with predictions being made of how the woven structure will behave in 3D.

The design of garments is a labour-intensive manual activity in which it has been difficult to use computers other than as a means of sketching. The fixing of dimensions only occurs when the garment structure and associated patterns have been decided. A proposal for starting and continuing the design process in a dimensionally accurate and controlled environment is presented. Garments are modelled as three-dimensional surfaces and corresponding patterns are derived. Visualization of the complete garment can proceed when the fabric parameters are specified and drape is performed relative to a body form.

The process of making connections between the different layers in a printed circuit board requires holes to be drilled which are subsequently plated. A trend towards miniaturization of board detail requires smaller holes to be drilled. However, the smaller-size drills are inherently more prone to breakage and must be used within a restricted range of drilling and process parameters. In a typical cycle, a drill encounters alternate layers of copper separated by a glass-resin composite. Drill forces, comprising an end-load and a torque, depend upon the process conditions and the composition of the material being cut. This paper examines the forces during a typical drilling cycle. Force trends associated with wear, glass content, chip-load and aspect ratio are presented together with an indication of the contribution from the copper layers. Recommendations for the selection of process parameters to avoid drill breakage due to excessive forces are given.

The problem of deriving patterns from 3D surfaces is described. An algorithm is presented for the flattening of 3D surfaces described in terms of a list of triangles. The algorithm incorporates an energy model in terms of the strain energy required to deform the edges of the triangular mesh. Also considered is the problem of arbitrarily siting darts or gussets to assist in the fitting process. The operation of the algorithm is demonstrated by fitting patterns to a classical geometric shape. The sensitivity of the final pattern to the algorithm's parameters is examined. Results are presented which quantify the strain energy reductions as a result of inserting darts or gussets in the pattern.

A component of the direct operating cost of aircraft is that associated with the manufacturing cost. This affects depreciation, interest, insurance and maintenance charges. By relaxing the requirements for aerodynamic surface smoothness the manufacturing cost can be reduced at the expense of an increase in drag and corresponding fuel costs. This work is part of a study to examine this multidisciplinary problem. Only isolated turbofan nacelles are considered. The costs associated with assigning different tolerance levels to the feature dimensions on nacelles are assessed. A statistical procedure is employed to estimate the cost-tolerance relationship for eleven features involving gaps, steps, surface profile and fastener flushness. This procedure requires actual manufacturing and cost source data. A knowledge of the cost-tolerance relationships is useful in a concurrent engineering context. It will allow aerodynamicists to optimise surface smoothness in consultation with production engineers, thus achieving the best compromise between cost and drag.

A complex of ethyne and chlorine monofluoride has been identified and characterised in a supersonically expanded mixture of the two gases by means of its ground-state rotational spectrum. A fast-mixing nozzle was used in combination with a pulsed-nozzle, Fourier-transform microwave spectrometer to preclude chemical reaction of the components and to observe the spectrum of each of the isotopomers C2H2⋯35ClF, C2H2⋯37ClF and C2D2⋯35ClF. Analysis of the spectrum led to the rotational constants A0, B0 and C0, the centrifugal distortion constants ΔJ, ΔJK and δJ, the Cl-nuclear quadrupole coupling constants χaa(Cl) and χbb(Cl)–χaa(Cl), and the spin–rotation coupling constant ½[Mbb(Cl)+Mcc(Cl)] in each case. Arguments based on nuclear-spin statistical weight effects and a detailed interpretation of the spectroscpic constants revealed that the detected pre-reactive intermediate has a planar T-shaped geometry, with C2H2 acting as the bar of the T, and ClF as the stem but oriented so that the Cl atom was closer to the ethyne π-bond than F. The distance between the centre (*) of the π-bond and the Cl nucleus is r(*⋯Cl)= 2.783 (8)A. The small intermolecular stretching force constant kσ= 10.0 N m–1 and the minor changes in the Cl nuclear qudrupole coupling constants of ClF on formation of the complex demonstrate that the complex is weakly bound and that the electric charge distribution of ClF suffers only a small perturbation. It is concluded that C2H2⋯ClF is best described formally as a complex of the Mulliken bπ· aσ weak outer type.

A weakly bound complex of NH 3 and F 2 has been detected as a pre-reactive intermediate in mixtures of the component gases and characterised by means of its ground-state rotational spectrum. Chemical reaction of NH 3 and F 2 was precluded by using a fast-mixing nozzle in a Fourier-transform microwave spectrometer. Spectroscopic constants B 0 , D J and D JK are reported for both symmetric-top isotopomers H 3 14 N…F 2 , and the 14 N-nuclear quadrupole constant is given for the former species. The complex has a geometry H 3 N…FF of C 3v symmetry, with r( N…F ) = 2.708(7) A and the intermolecular force constant k σ = 4.69(3) N m −1 .

The reaction between H 2 S and ClF was precluded and H 2 S…ClF isolated by a coaxial supersonic expansion of the gaseous components into the Fabry-Perot cavity of a pulsed-nozzle, Fourier-transform microwave spectrometer. The ground-state rotational spectra of seven isotopomers of H 2 S…ClF were analysed and gave in each case the spectroscopic constants 1 2 (B 0 + C 0 ), D J , χ aa (Cl) and M bb (Cl). Interpretation of these constants revealed the complex to have a geometry of C s symmetry with the S…ClF nuclei collinear in the order shown, with the angle 180°− φ = 84.2(4)° between the C 2 axis of H 2 S and the S…ClF axis, and with r( S…Cl ) = 2.857(3) A .

The ground-state rotational spectra of four isotopomers of the complex OC3.C1F have been observed by using a fast-mixing nozzle in a pulsed-nozzle, Fourier-transform microwave spectrometer. The spectrum of the reaction product carbonyl chloride fluoride was detected by its intensity indicated that the extent of the reaction was small. The observed spectroscopic constants B 0 , D J , χ aa (Cl) and M bb (Cl) were interpreted to show that the pre-chemical complex has the nuclei collinear in the order OC3.C1F, with r( C 3. Cl ) = 2.770(3) A and the intermolecular stretching force constant k σ =7.03(3) N m −1 . There is only a minor electric charge redistribution within C1F on complex formation.

Ground-state rotational spectra of several isotopomers of a linear complex formed between HCN and BrCl were observed by pulsed-nozzle, F-T microwave spectroscopy and analysed to give the spectroscopic constants B0, DJ, χ(Br), χ(Cl), and Mbb(Br). The order HCN…BrCl of the nuclei was established from the changes in the B0 values on isotopic substitution. The small fractional electronic charge (δ ≈ 0.05) transferred from Br to Cl on complex formation and the intermolecular stretching force constant (kσ ≈ 11 N m−1) estimated from the spectroscopic constants indicates a weak interaction of HCN and BrCl, with little perturbation of the charge distribution of BrCl.

A complex of ethene and Cl2 has been characterised in the gas phase. Rotational spectra of the isotopomers C2H4…35Cl2, C2H4…35Cl37Cl and C2H4…37Cl35Cl were recorded by using a fast-mixing nozzle in an FT microwave spectrometer. Rotational constants, centrifugal distortion constants and Cl nuclear quadrupole coupling constants. χgg (Cl) are reported in each case. The complex is of the π-donor–acceptor type and has a C2v geometry in which Cl2 lies along the C2 axis perpendicular to the plane of the C2H4 nuclei. The binding is weak, and only small changes in the χgg (Cl) attend complex formation. A simple model attributes these changes to a transfer of around 0.02e from the inner to the outer Cl nucleus, thus confirming that the complex is of the Mulliken outer type. Similarities in the properties of C2H4… Cl2 and C2H4… HCl indicate that the angular geometry is in both cases determined mainly by the electrostatic part of the interaction. The distance from the π-bond midpoint to Cl decreases from C2H4… HCl to C2H4… Cl2; this suggests that Cl2 is “snub-nosed”.

The ground-state rotational spectra of five isotopomers (H2S⋯35Cl2, H2S⋯35Cl37Cl, H2S⋯37Cl35Cl, HDS⋯35Cl2 and D2S⋯35Cl2) of a complex formed by hydrogen sulfide and chlorine have been observed with a pulsed-nozzle, Fourier-transform microwave spectrometer. The reaction of H2S and Cl2 was precluded by employing a fast-mixing nozzle. The rotational constant ½(B0+C0), the centrifugal distortion constant DJ and the Cl-nuclear quadrupole coupling constants χaa(Cli) and χaa(Cl0)(i = inner Cl atom, o = outer Cl atom) were determined in each case. The rotational constants were interpreted, under the assumption of unperturbed monomer geometries, to establish that H2S⋯Cl2 has a geometry in which the SClCl nuclei are collinear or almost collinear, with the Cl2 subunit nearly perpendicular to the plane of the H2S nuclei. The observed angular geometry is rationalised in terms of a set of rules previously used to discuss hydrogen-bonded complexes B⋯HX. The strength of the interaction, as measured by the force constant kσ(determined from DJ), and the electric charge redistribution within Cl2 on formation of H2S⋯Cl2[determined from the χaa(Clx)] both indicate that the complex is of the weak, outer type described by Mulliken. A comparison of the properties of H2S⋯Cl2 and H2S⋯HCl reveals that the complexes are similar in several respects and explanations for these similarities are given in terms of the electric charge distributions of Cl2 and HCl. In particular, the reason why the angular geometries of both can be predicted by some electrostatically based rules is discussed.

An intermediate C2H2⋯Cl2 belonging to the bπ.aσ class of complex defined by Mulliken has been isolated in a reactive mixture of ethyne and molecular chlorine and characterised by means of its ground-state rotational spectrum, as observed with a fast-mixing nozzle incorporated in a pulsed-nozzle, Fourier-transform microwave spectrometer. Rotational constants A0, B0 and C0, quartic centrifugal distortion constants ΔJ, ΔJK and δJ, and Cl-nuclear quadrupole coupling constants χaa(Clx) and χbb(Clx)–χcc(Clx)(where x= i for inner or o for outer) were determined for the four isotopomers C2H2⋯35Cl2, C2H2⋯37Cl35Cl, C2H2⋯35Cl37Cl and C2D2⋯35Cl2. Detailed analyses of the spectroscopic constants established unambiguously that the observed complex has a planar, T-shaped geometry of C2v symmetry with Cl2 as the stem of the T, that the extent of electric charge redistribution within Cl2 on formation of the complex is equivalent to a transfer of only 0.02e from Cli to Clo, and that the binding strength, as measured by the intermolecular stretching force constant kσ, is very small. The systematic shortening of the B⋯Cl distance from B⋯HCl to B⋯Cl2 identified previously was also observed for B = C2H2 and has been attributed to the ‘snub-nosed’ nature of molecular chlorine.

A T-shaped planar complex of ethyne and Cl 2 has been isolated in a mixture of the substances using a pulsed-nozzle, FT microwave spectrometer and characterised through its rotational spectrum. Rotational constants ( A 0 , B 0 , C 0 ), centrifugal distortion constants (Δ J , Δ JK , δ J ), and Cl-nuclear quadrupole coupling constants χ aa (Cl) and χ bb (Cl)  χ cc (Cl) of both Cl nuclei are reported for the isotopomer (HCCH, 35 Cl 2 ). The angular geometry, electric charge redistribution within the Cl 2 subunit and intermolecular force constant k σ , as derived from the spectroscopic constants, are compared with those of other B…Cl 2 and of the corresponding series B…HCl to give some generalisations.

Pulsed-nozzle, Fourier transform-microwave spectroscopy has been used to observe the symmetric-top rotational spectrum of the most abundant isotopic species of 1-iodoadamantane. The I nuclear quadrupole coupling constant has been determined to be −1675.2(1) MHz in the ground state, and has been compared with the values for a series of iodohydrocarbons. The rotational constant, centrifugal distortion constants and spin—rotation constant have also been measured to be B 0 =421.72219(8) MHz, D J =0.0065(3) kHz, D JK =0.0269(8) kHz and C N =1.563(9) kHz.

In the apparel field, there is the problem of creating a design with respect to an underlying standard form. Instead of applying general-purpose three-dimensional computer aided design systems to such tasks it is proposed that design can be carried more efficiently with bespoke design systems. These can be targeted to deal with the problems of accurately defining the offset surfaces which comprise the garment. Such a system is introduced and the methods of data entry are discussed. Position on the three-dimensional form is determined using a digitizer tablet and fit with respect to the form is specified by an offset dimension. It is shown that complex garment pieces with variable fit can be quickly specified within the system.

[1] Laboratory experiments are performed which study the behavior of two-dimensional vortex dipoles propagating toward a rectilinear step change in depth. The dipoles are formed in a homogeneous shallow water layer by an impulsive jet and approach the step from either relatively deep or shallow water at normal or oblique incidence. Qualitative observations agree well with previous theoretical predictions: At normal incidence the separation of the two vortices forming the dipole increases for a dipole crossing from deep water and decreases for a dipole crossing from shallow water. Dipoles with oblique angles of incidence refract toward the normal when passing into shallower water, and dipoles that cross the step into deep water refract away from the normal. Dipoles approaching from shallow water at sufficiently large angles of incidence reflect off the step.

A method for the design of garments at a workstation is proposed. An underlying body form analogous to a trade mannequin is first represented in the computer. Garment panels are considered to be surfaces of complex shape, whose fit with respect to body form may vary over the surface. A method of easy entry of data for representing panels is proposed, whereby fit around panel edges can be defined. The problems of controlling fit in the interior of panels is considered and a scheme is proposed which accomplishes design with economy of effort from the designer.

With traditional two-dimensional based interfaces, many CAD surface models, such as automobile bodies and ship hulls, are difficult to design and edit due to their 3D nature. This paper discusses the haptic-based deformation for the design of CAD surface models. With haptic devices (force feedback interfaces) designers can, in virtual space, touch a native B-rep CAD model, and use their tactile senses to manipulate it by pushing, pulling and dragging its surfaces in a natural 3D environment. The paper presents shape control functions. By using the shape functions, designers can directly manipulate and deform a selected region of a surface to the desired shape, and generate complex geometry with simple operations. Force feedback gives designers the greatest flexibility for the design of complex surfaces.Copyright © 2004 by ASME

(2003). The prevalence of psychiatric morbidity among homeless adults. International Review of Psychiatry: Vol. 15, No. 1-2, pp. 134-140.

This article presents some findings about adults with a psychotic disorder who were identified in the OPCS surveys of psychiatric morbidity. The main aim of the analysis was to identify characteristics associated with differences in the circumstances and health-related behaviour of adults aged 16-64 with psychosis. The analysis covers people who were identified by the various criteria used on the surveys as having a psychotic illness and who were considered to be living in private households. First we describe briefly the survey methods used and how diagnoses of psychosis were derived. We then present results from four topic areas covered in the analysis. These are: use of medication, use of health services, difficulties with activities of daily living, and social support.

Virtual reality (VR) devices, such as haptic (force feedback) devices, provide users with virtual environments where they can interact with digital models in 3D. Haptic devices show great promise for use in design. However, current haptic systems are used primarily to verify rather than to interact with CAD systems to modify a design. In order to use haptic devices in the design of CAD models, we use component technology (COM+) to develop a novel haptic model system—which we have termed super-object modeling. The novel haptic model solves several crucial problems for seamlessly integrating CAD models with haptic models, such as the efficient exchange of complex models in real-time, real-time model updating, and the issue related to CPU power etc. Based on this super-object modeling, we have developed a virtual reality system, called Virtual DesignWorks. The system provides a new approach to 3D design—Designing CAD models via touch interaction. Engineers or designers can, in virtual space, directly touch native B-rep CAD models, feel and deform the CAD models rather than just verify a design. Super-object modeling represents the first development of haptic geometric models based on component technology. It demonstrates significant advantages compared to the traditional haptic models. With this technology, touch interaction has the potential to become a critical interface of design, and force feedback gives designers the greatest flexibility for 3D design.

Department of Computer Science, Brunel UniversityUxbridge, Middlesex UB8 3PH, UKB. K. Hinds and J. McCartneyDepartment of Mechanical and Manufacturing EngineeringQueen's University, Belfast BT9 5AH, Northern IrelandABSTRACTShoe uppers are often constructed of panels which overlap one another and which may or may not have been thinnedalong the periphery. One of the visual features important to aesthetic shoe CAD is the profile variation along thepanel boundary caused by either stitching or compressed gluing. Based upon an understanding of geometricrequirements, the following issues are addressed: offset curve generation according to a classification of localgeometry of an arbitrary 3D surface patch; cross section type handling; profile representation and rendering.Key words: aesthetic shoe CAD, surface rendering, bump mapping, offset curve1JNTRODUCTIONPrototyping and sample evaluation is very time consuming and expensive in the footwear industry as in most fashionindustries. Only a very small proportion of sathples are eventually accepted and manufactured. In addition, designflexibility and quick response times are demanded by a highly competitive market.Computer advances have now made a high degree of visual realism possible. Although the visual accuracy of acomputer generated image does not contribute to the geometric design directly, it is vital to highlight the aestheticfeatures of a design during the sample evaluation stage. Textures, wrinkles, stitching runs and other detailedgeometric variations all contribute towards making a design representation realistic.Shoe uppers are made by stitching panels together. Neighbouring panels overlap one another either with or withoutbeing thinned along the overlapping periphery. One of the important visual features of shoe uppers is the profilevariation along panel boundaries caused by gluing and stitches. Since the upper panels are normally 3D free formsurfaces, the geometric properties need to be fully understood before such kind of the geometric perturbation can berealistically represented. This paper discusses how a panel profile varies along the panel periphery and how this canbe translated in terms of the visual effects along certain boundary edges.2. BOUNDARY PROFILES OF SHOE UPPER PANELSShoe uppers are constructed of pieces of upper material called shoe panels which can be made of different materialsdepending on the shoe type. Such materials include natural and synthesised leather, canvas and other textiles. Interms of geometry, a panel is usually a 3D free form surface patch with boundary edges of arbitrary shape. To formthe whole upper of a shoe, panels are connected together either by stitching or compressed gluing. In addition, panelsegmentation and profile variation serve an important aesthetic purpose in footwear design. In fact. colour andmaterial texture, tessellation of shoe panels and the profile perturbation resulting from the manufacture processes areexamples of the fine details that contribute towards the overall aesthetics of a design.

In all jawed vertebrate species, antibody diversity is specified by an immunoglobulin monomeric structure consisting of two heavy chains and two light chains. Different immuno-globulin classes are associated with various polymeric configurations of the basic monomer. Immunoglobulin-like heterodimers also occur in the jawless vetebrates (cyclostomes) of which the only extant representatives are the lampreys and hagfishes (Varner and Litman, unpub-lished observations);1-2 primary structure data that would firmly establish these as antibodies, however, are not available presently. During the past several years, our labora-tory has identified immunoglobulin genes in species that are considered to represent signifi-cant departure points in vertebrate phylogeny.3 Taken together with the descriptions of im-munoglobulin genes in avians4,5 and mammals,6 a reasonably complete picture of the over-all evolution of immunoglobulin gene structure and diversity is emerging. In all of these species, the most distinctive features of the immunoglobulin gene system, segmental organiza-tion and selective rearrangement in somatic tissues, are preserved. The structures of indivi-dual heavy chain variable (VH), diversity (DR), joining (JH) and certain constant region (CR) segmental elements are also remarkably similar. Two additional features of higher, vertebrate immunoglobulin genomic organization, the split leader and recombination signal sequences (RSSs), also are found in lower vertebrates. Furthermore, the exon-intron organization of the constant region found in Heterodontus (horned shark), the most phylogenetically primitive vertebrate studied thus far, is equivalent to that described in mammals.7 To a certain degree, some of these findings are not unexpected since in many cases the genes in lower vetebrates were detected by cross-hybridization with a particular mammalian immunoglobulin heavy chain gene probe.8,9

The general motion of a pair of point vortices of arbitrary circulations in two-dimensional ideal shallow water near topography in the form of rectilinear step is found using Hamiltonian techniques. Paths are determined by the constants of motion: energy, linear impulse, and circulation. The behavior of vortex patches in the same geometry is computed using contour dynamics. Comparisons of point vortex and patch trajectories are found to be close provided the vortex patch centroids are sufficiently far away from the escarpment. For special values of the constants of motion, vortex pairs that propagate steadily parallel to the escarpment without deformation are found (that is, vortex pair equilibrium states) and exist even when the circulation of each vortex has the same sign.

A T-shaped complex formed between acetylene and bromine monochloride is identified and characterised through its rotational spectrum, as detected in a mixture of the two components by using a fast-mixing nozzle incorporated into a pulsed-nozzle, F–T microwave spectrometer.

Pre-reactive complexes B ⋯ ClF, where B is ethyne or ethene, of C2v symmetry have been isolated in mixtures of B and ClF by using a fast-mixing nozzle in a pulsed-nozzle, Fourier-transform microwave spectrometer and characterised by their rotational spectra.

The rotational spectrum of a complex of C2v symmetry has been detected in a mixture of ethene and molecular chlorine by using a pulsed nozzle, Fourier-transform microwave spectrometer; the Cl2 molecule lies along the C2 axis of ethene that is perpendicular to the molecular plane and interacts only weakly with the π bond.

The immunoglobulin (Ig) heavy chain variable (VH) gene family of Heterodontus francisci (horned shark), a phylogenetically distant vertebrate, is unique in that VH, diversity (DH), joining (JH) and constant region (CH) gene segments are linked closely, in multiple individual clusters. The V regions of 12 genomic (liver and gonad) DNA clones have been sequenced completely and three organization patterns are evident: (i) VH-D1-D2-JH-CH with unique 12/22 and 12/12 spacers in the respective D recombination signal sequences (RSSs); VH and JH segments have 23 nucleotide (nt) spacers, (ii) VHDH-JH-CH, an unusual germline configuration with joined VH and DH segments and (iii) VHDHJH-CH, with all segmental elements being joined. The latter two configurations do not appear to be pseudogenes. Another VH-D1-D2-JH-CH gene possesses a D1 segment that is flanked by RSSs with 12 nt spacers and a D2 segment with 22/12 spacers. Based on the comparison of spleen, VH+ cDNA sequences to a germline consensus, it is evident that both DH segments as well as junctional and N-type diversity account for Ig variability. In this early vertebrate, the Ig genes share unique properties with higher vertebrate T-cell receptor as well as with Ig and may reflect the structure of a common ancestral antigen binding receptor gene.

A thermal model is derived for a heat source moving at constant velocity. Experimental data are presented to define the shape of the heat source and its overall efficiency in this mode. The resultant temperature field at the entry to the cutting zone is thus defined and the positioning of the torch to achieve the greatest benefit is discussed. Also consideration is given to the effects of excess heating on the surface layers of the work.

SUMMARY An adaptive control system is proposed in which a given amount of tool wear is allowed per operation. The objective of the control system is to machine a certain feed distance in the minimum tune using no more than the wear allowed and working within the conventional adaptive control constraints. The average rate at which the operation progresses can thus be regulated by appropriately setting the wear target. The adaptive control system has been applied to the control of a lathe performing a simple bar turning operation. An on-line computer receives transducer responses, calculates and issues feed and speed corrections. The optimization policy requires the tool wear rate to be estimated while cutting and in this work the estimation was made from the cutting process variables including the tool-work thermocouple voltage. Workpiece disturbances in the form of hardness changes were introduced and the experimental responses of the control system to these disturbances are presented. The success of esti...

In the high speed machining of metals it has been established that the shearing process is frequently non-uniform resulting in a serrated chip with highly localised shearing. This type of chip formation is promoted solely by the properties of the material being machined and is not initiated by vibrations or resonances of the machine structure. It has been found that this type of unsteady, shear localised chip form can be duplicated when polyethylene is machined at low speeds with araldite cutting tools. By means of a photoelastic technique the variations in tool stress associated with these non-uniform chip forms has been revealed during the machining process. The photoelastic results clearly show that the tool stresses oscillate in a regular manner during the formation of each chip segment. The results obtained have lead to a better understanding of the chip formation process and provide a more complete description of the stress conditions experienced by the cutting tool.