The hypothesis that lean manufacturing audits are an effective way to measure improvements in operational performance was tested using 64 manufacturing sites owned by a FTSE 100 company. Commonly-used lean characteristics were evaluated: policy deployment, standardised work, visual management and housekeeping, quick changeover techniques, total productive maintenance, continuous improvement (kaizen), error proofing, cultural awareness, material control, and levelling (heijunka). Operational performance was assessed employing commonly-used operational performance measures: on-time-delivery, inventory turns, and direct labour utilisation. The findings are that lean manufacturing audits are effective in measuring improvements in operational performance provided that the audit scope and the lean characteristics are aligned up front. OPSOMMINGDie hipotese dat die amptelike evaluering van stroombelynde produksie effektief gebruik kan word om verbetering in bedryfsdoeltreffendheid te meet, is getoets met die gebruik van 64 vervaardigingsaanlegte wat deur 'n FTSE 100 maatskappy besit word. Stroombelynde tegnieke wat algemeen gebruik word, is geëvalueer: strategiese beplanning, gestandaardiseerde werk, visuele bestuur en huishouding, vinnige oorgangstegnieke, totale gehaltebestuur, kaizen, foutvoorkoming, kulturele bewustheid, materiaalbeheer, en konstante produksietempo's. Maatreëls wat algemeen gebruik word om bedryfsdoeltreffendheid te meet is gebruik om bedryfsdoeltreffendheid te assesseer: tydige aflewering, voorraadomsetsnelheid, en direkte arbeidsbenutting. Die bevinding is dat, om amptelike evaluering van stroombelynde produksie effektief te gebruik om verbetering in bedryfsdoeltreffendheid te meet, moet die omvang van die amptelike evaluering en stroombelynde tegnieke vooraf belyn word. a a a a a a a a a a aa a a a a 1*

We introduce a new class of ventilated brake disk which incorporates an open cellular core: wire-woven bulk diamond (WBD). Transient and steady-state thermofluidic charac teristics are presented. As reference, a commercially available pin-finned brake disk is also considered. At a braking power of 1.9 kW, representative of a medium sized truck descending a 2% gradient at a vehicle speed of 40 km/h (i.e., 200 rpm), the WBD cored brake disk reduces the overall brake disk temperature by up to 24% compared to the pinfinned brake disk. Results also reveal that in typical operating ranges (up to lOOOrpm), the WBD core provides up to 36% higher steady-state overall cooling capacity over that obtainable by the pin-finned core. In addition, the three-dimensional morphology of the WBD core gives rise to a tangentially and radially more uniform temperature distribu tion. Although the WBD core causes a higher pressure drop, this is balanced by the bene fit o f a stronger suction of cooling flow. Flow mixing in an enlarged heat transfer area by the WBD core is responsible for the substantial heat transfer enhancement. The WBD core is mechanically strong yet light while providing a substantial reduction in a brake's operating temperature.

The transient thermal response of a newly developed ventilated brake disc cored with a porous medium (wire-woven bulk diamond) is compared with those of a solid brake disc and a conventionally ventilated brake disc with pin fins. The best-performing brake disc vis-à-vis the operating temperature is dependent on the duration of braking: for a short braking event, T(solid) \ T(pin-finned) \ T(porous); however, for extended braking T(porous) \ T(pin-finned) \ T(solid). These experimental results are explained in terms of the governing thermophysical parameters using a classical firstorder unsteady-state differential equation. The initial rate of increase in the brake disc temperature is dominated by the thermal capacity term; hence, for a short braking event, solid discs with a large thermal capacity operate at a low temperature. However, for extended braking, ventilated discs run cooler and reach lower steady-state temperatures than solid rotors do owing to the increased convective surface area and the forced convection in the ventilated channels. With the wire-woven bulk diamond core which allows a slightly lighter disc than the conventional pin-finned disc, a substantially lower steady-state temperature can be achieved, resulting from promoted flow mixing by three-dimensional wire-woven bulk diamond ligaments which enhance convection.

The flow behavior through the vented channel of a brake disk determines its thermal performance, viz. its resistance to brake fade, brake wear, thermal distortion, and thermal cracking. We present experimental results of the flow characteristics inside the vented channel of a radial vane brake rotor with a selected number of vanes (i.e., 18, 36, and 72) but constant porosity (ε ∼ 0.8) at low rotational speeds (i.e., 25 rpm ≤ N ≤ 400 rpm). Using bulk flow and velocity field mapping measurement techniques, we observed that increasing the number of vanes for a given rotational speed results in (i) the increase in the mass flow rate of the air pumped by the rotor, (ii) the reduction of inflow angle (β) becoming more closely aligned with the vanes, (iii) more uniformly distributed passage velocity profiles, and (iv) increased Rossby number. In addition, for a certain range of rotational speeds (i.e., 100 rpm ≤ N ≤ 400 rpm), we identified the biased development of streamwise secondary flow structures in the vented passages that only form on the inboard side of the rotor. This is due to the entry conditions where the incoming flow must transition sharply from the axial to the radial direction as air is drawn into the rotating channel. The biased secondary flow is likely to cause uneven cooling of the brake rotor, leading to thermal distortion. At lower rotational speeds (i.e., N < 100 rpm), the biased secondary flows transitions into a symmetric structure.

The material selection of prostheses in developing countries is currently biased towards what is readily available and ignores important criteria such as patient comfort and structural strength. In this study, the ELECTRE III multiple attribute decision-making method was applied to the material selection of a paediatric prosthetic knee. Light metals were considered as candidates for selection. While composites are light, they are not suitable for use in components with sliding and mating surfaces such as a prosthetic knee. Plastics are prone to failure. Candidate materials were evaluated on criteria related to patient fatigue and comfort, structural stability and material cost. The patient fatigue and comfort requirement was evaluated using material density as the weight of the prosthesis affects the comfort level. Finite element analyses simulating the ISO 10328:2006 standard for structural testing of lower limb prostheses were used to evaluate the structural strength suitability of the candidate materials. The present day prices of the raw material of the candidates were used as an index of material cost. Wrought aluminium alloy aluminium 7175 was ranked highest while titanium alloys were ranked below these due to their higher cost. Cast aluminium alloys ranked lowest due to their poor structural performance. The study, using ELECTRE III, a rigorous multi-criteria decision analysis method, shows that aluminium 7175 is the optimal light metal material for a paediatric prosthetic knee.