Therapeutic management in trochanteric fractures

The authors present the management of trochanteric fractures based on 343 fractures treated in Department of Orthopaedics and Trauma in Clinical Hospital of Emergencies of Ia?i for 5 years. The non-operative treatment was used in 17.2% of cases and the conservative methods were plaster immobilization, continuous traction and early mobilization. The surgical treatment was used in 82.8% of cases. The reduction of the fractures was usually possible using closed methods. For fixation, the authors used four types of implants: the 135 degrees blade-plate in 9.2% of cases, the condylar blade plate in 44.7%, Ender nails in 45.4% and DHS in 0.6% of cases. The choice of one of this methods depends on the type of fracture, age of the patient and on his biological status.     

Rendering complex scenes for psychophysics using RADIANCE: how accurate can you get?

Rendering packages are used by visual psychophysicists to produce complex stimuli for their experiments, tacitly assuming that the simulation results accurately reflect the light-surface interactions of a real scene. RADIANCE is a physically based, freely available, and commonly used rendering software. We validated the calculation accuracy of this package by comparing simulation results with measurements from real scenes. RADIANCE recovers color gradients well but the results are shifted in color space. Currently, there is no better simulation alternative for achieving physical accuracy than by combining a spectral rendering method with RADIANCE.     

Representing Animations by Principal Components

In this paper, we present a representation for three-dimensional geometric animation sequences. Different from standard key-frame techniques, this approach is based on the determination of principal animation components and decouples the animation from the underlying geometry. The new representation supports progressive animation compression with spatial, as well as temporal, level-of-detail and high compression ratios. The distinction of animation and geometry allows for mapping animations onto other objects.     

Constrained Modelling of 3‐Valent Meshes Using a Hyperbolic Deformation Metric

Polygon meshes with 3‐valent vertices often occur as the frame of free‐form surfaces in architecture, in which rigid beams are connected in rigid joints. For modelling such meshes, it is desirable to measure the deformation of the joints' shapes. We show that it is natural to represent joint shapes as points in hyperbolic 3‐space. This endows the space of joint shapes with a geometric structure that facilitates computation. We use this structure to optimize meshes towards different constraints, and we believe that it will be useful for other applications as well.     

PWM technique with partially constant modulating waves

Contents In this paper the waveform quality and overmodulation region voltage-gain characteristic of pulsewidth-modulation (PWM) method with partially constant modulating waves are investigated. Thus the number of switchings in the three-phase inverter diminishes by 33 as compared to the classical methods. The PWM version proposed, in which during π/3 intervals only two switchings of the inverter semiconductor devices are performed, can also be matched much better to the methods for accomplishing the switchings of these devices according to the ZVS principle.

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Ubersicht Im vorliegenden Aufsatz wird die Qualit?t der Wellenformen sowie die Charakteristik des Gewinns an Spannung für den Bereich der Supramodulation im Falle der Pulsbreitenmodulationstechnik (PWM) mit partiell konstanten Modulationssignalen studiert. Auf diese Weise wird die Kommutationsanzahl in einem Dreiphasen-Wechselrichter um 33 verringert im Vergleich zur klassischen PWM-Methode. Die vorgesch lagene PWM-Variante, wo in den Winkelbereichen von π/3 nur zwei Kommutationen der Halbleitervorrichtungen im Wechselrichter durchgeführt werden, kann besser an die Kommutationsmethoden dieser Vorrichtungen nach dem ZVS-Prinzip angepasst werden.

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Received: 30 June 1999     

Perfect Laplacians for Polygon Meshes

A discrete Laplace‐Beltrami operator is called perfect if it possesses all the important properties of its smooth counterpart. It is known which triangle meshes admit perfect Laplace operators and how to fix any other mesh by changing the combinatorics. We extend the characterization of meshes that admit perfect Laplacians to general polygon meshes. More importantly, we provide an algorithm that computes a perfect Laplace operator for any polygon mesh without changing the combinatorics, although, possibly changing the embedding. We evaluate this algorithm and demonstrate it at applications.     

Particle atomic layer deposition of alumina for sintering yttria-stabilized cubic zirconia

The addition of aluminum oxide (Al₂O₃) as a sintering aid to yttria-stabilized zirconia (YSZ) reduces the required densification temperature. Sintering aids are incorporated using a number of processes which can lead to ambiguity when determining the effect of the sintering aid on the densification mechanism. In this study, a novel method for sintering aid addition, Particle Atomic Layer Deposition (ALD), was used to deposit an amorphous Al₂O₃ thin film on YSZ particles. Transmission electron microscopy confirmed the deposition of conformal Al₂O₃ thin films on the surface of the YSZ particles. The addition of Al₂O₃ to YSZ reduced the temperature at which densification began by ~75°C, and 2.2 wt% Al₂O₃ addition resulted in a minimum activation energy for the intermediate stage of densification. This concentration is well in excess of the solubility limit of Al₂O₃ in YSZ, showing that Al₂O₃ does not enhance the densification of YSZ solely by dissolving into the YSZ lattice and activating volume diffusion. The addition of 0.7 wt% Al₂O₃ with one Particle ALD cycle enhanced the ionic conductivity of YSZ by 23% after sintering at 1350°C for 2 hours, demonstrating that dense parts with high oxygen ion conductivities can be produced after sintering at reduced temperatures. One Particle ALD cycle is a fast, easily scaled-up process that eliminates the use of solvents and has substantial cost/performance advantages over conventional processing.     

Effect of κ-carrageenan on rheological properties, microstructure, texture and oxidative stability of water-in-oil spreads

The effect of κ-carrageenan concentration (0-7.5 g kg⁻¹) on the rheology, microstructure, texture and oxidative stability of water-in-oil (W/O) spreads (600 g fat kg⁻¹ emulsion) was examined over 60 days storage time. Results showed that increasing the κ-carrageenan concentration to 7.5 g kg⁻¹ significantly increased the viscosity of the aqueous phase (to 42.7 mPa s at 60 °C) resulting in gelation of the aqueous phase on cooling. The microstructure of the spreads was disrupted by higher levels of κ-carrageenan, resulting in a less homogeneous distribution of the aqueous phase. Melt temperature (where tan δ > 1) decreased significantly from 62 to 56.2 °C with increasing κ-carrageenan concentration from 0 to 7.5 g kg⁻¹. The firmness and the G′ at 6 °C for all samples were significantly increased after 60 days storage with only small effects due to κ-carrageenan levels. Oxidation of the fat phase was evident by the significant increases in peroxide values of all spreads on storage, with κ-carrageenan exhibiting no antioxidant behaviour. While increased κ-carrageenan levels modified the microstructure of W/O spreads in terms of the droplet size of the aqueous phase and its distribution few changes were evident in the continuous fat phase.     

Betontechnologie und Dauerhaftigkeit von glasfaserbewehrten Bauteilen

Concrete Technology and Durability of Glass Fibre Reinforced Structures The durability of glass fibre reinforced concrete structures is significantly determined by matrix composition, the type of glass and its surface quality including necessary coatings. In the paper an experimental overview is given concerning special material influences and their interaction in the composite.