Growth rate of multiple intracranial hydatid cysts assessed by CT from the time of embolisation

The authors report a case of necrotizing glomerulonephritis, with granular immune deposits, leading to the etiologic diagnosis of splenic non-Hodgkin's Lymphoma (NHL). The serum creatinine, initially markedly elevated, decreased under steroids and chlorambucil. Unfortunately, the patient died from septic complications. The importance of a careful search for a (localized) NHL in case of necrotizing glomerulonephritis with granular immune deposits is emphasized.     

Image sequence stabilisation using fuzzy adaptive Kalman filtering

Image sequence stabilisation based on fuzzy adaptive Kalman filtering of absolute frame displacements is proposed. Two Kalman filters are operated in parallel, one of which is used as a reference filter and is run with a constant high process noise variance to enable smooth and close tracking of global camera displacements. The process noise variance of the stabilisation filter is adaptively varied according to the residual between the stabilisation filter and the reference filter output.     

The effect of excessive steam curing on Portland composite cement concrete

Steam curing at atmospheric pressure is an important technique for obtaining high early strength values in precast concrete production. Cement type, as well as curing period and temperature, is an important parameter in the steam-curing process. PC42.5 is the type of cement that is most commonly used in Turkish precast concrete plants. Its behavior is well known. Nowadays, the production of composite cements is becoming more popular every other day due to its advantages. The object of this study was to determine the properties of this relatively new binder comparatively with conventional PC42.5 under steam curing. For this purpose, 15-cm concrete cubes were prepared with a water/cement ratio (W/C) of 0.44 and were subjected to steam curing for five different curing periods of 4, 8, 16, 24 and 36 h under curing temperatures of 65 and 85 °C. Cement dosage was kept constant (400 kg/m³) for all specimens. The variation of compressive strength values and maturity for each condition has been presented comparatively within this study. Test results indicated that Portland composite cement (PKC/A42.5) can be used in place of PC42.5 for steam curing at atmospheric pressure in precast concrete production. However, in case of early high strength demand for early demolding purposes, curing temperature should be increased to 85 °C for PKC/A42.5 cement concretes.     

Subependymal giant-cell astrocytoma associated with tuberous sclerosis: case report

Tuberous sclerosis is a neurocutaneous syndrome with a wide variety of clinical, pathologic, and radiologic manifestations. Intracranial phakomatosis has been reported to include subependymal nodules; cortical tubers, and subependymal giant-cell astrocytomas. Subependymal giant-cell astrocytomas are rare, benign brain tumors of unknown histogenesis which cause increased intracranial pressure, seizures, and focal neurologic signs. The only treatment of these tumors is total surgical removal, because they are not sensitive to irradiation and chemotherapy. We report a patient with tuberous sclerosis who underwent surgery for a large subependymal giant-cell astrocytoma.     

Active and non-active porosity in concrete Part II: Evaluation of existing models

Mechanical, semi-empirical, and theoretical models suitable for describing concrete mechanical properties (modulus of elasticity, bulk modulus, and ultrasonic pulse velocity) are evaluated. Extensive experimental data is generated from saturated and dry concrete specimens with varying volume of active and non-active pores. Experimetnal data established that active and non-active pores appear at different aspect ratios furthermore, active pores change shape with moisture content. The experimental data is compared to those obtained from these three model categories. Models are evaluated based on their capability in evaluating the effect of pores during dry and saturated states. One model, capable of representing pores at various aspect ratios, was successful in describing mechanical properties in dry and saturated states.

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Résumé Les résultats d'une étude visant à évaluer la fiabilité de différents modèles permettant de prédire les propriétés mécaniques (module élastique, vitesse de propagation d'une onde ultrasonique) sont présentés. Trois différents types de modèles ont été considérés: des modèles mécaniques, semi-empiriques et théoriques. De nombreuses données expérimentales ont été générées dans le cadre de cette étude. Le programme expérimental visait à étudier le comportement d'éprouvettes de béton sec et humide préparé à différentes teneurs en pores actifs (pores capillaires) et non-actifs (vides d'air). Les résultats des essais indiquent que les pores actifs et non-actifs ont différents coefficients de forme et que la géométrie des pores actifs varie en fonction de la teneur en eau du béton. Les prédictions obtenues avec les différents modèles sont comparées aux valuers expérimentales. La capacité des modèles à prendre en considération l'influence des pores et de l'état hygrométrique du matériau a été évaluée. Les résultats de cette évaluation systématique démontrent que seul le modèle qui considère le coefficient de forme des pores permet de prédire correctement les propriétés mécaniques du béton à l'état sec et humide.

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Editorial Note Dr. Nataliya Hearn is a RILEM Affiliate Member.     

Computer aided operability analysis via interactive graphics

A comprehensive computer-aided design methodology utilizing the highly interactive capabilities between a graphics computer and the user is described. The program, CHESOPS, enables a flexible simulation of any arbitrary chemical process by synthesizing the process design about several steady state values and extending the analysis to the effects of design changes on process operability. In this way the process may be visualized within a dynamic environment from which interactive control system design and dynamic simulation takes place. The highly flexible nature of the program enables efficient and comprehensive investigation of alternative designs, control structures, and optimal operating conditions.     

Indentation of a cantilever beam or plate

In this paper the general plane problem for a semi-infinite strip fixed at its short end, containing a crack perpendicular to its voundaries is considered. The strip is under the effect of a stamp. By extending the crack to the surfaces, one can reduce the problem to that of c cantilever beam or plate. Integral transform technique is used to provide an exact formulation of this problem, in terms of a system of four singular integral equations one of them being second kind. Stress singularities at the corners of the fixed-end, at the crack tips and at the end points of the contact region undermeath the stamp are obtained from the singular integral equations which are then solved numerically.     

New morphological methods to generate two-dimensional curve offsets

For the purpose of generating 2D curve offsets used in 2.5D machining, four new methods based on morphological operations on different mathematical entities are presented in this paper. All of the methods, which lend themselves for parallel processing, exploit the idea that the boundaries formed by a circular structuring element whose center sweeps across the points on a generator/base curve comprise the entire offsets of the progenitor. The first approach, which is a carry-over from image processing, makes good use of morphological operations on binary images to produce 2D offsets via contour tracing algorithms. The second method, which is to rectify the high memory cost associated with the former technique, utilizes morphological operations on (boundary data) sets. The implementation of this basic technique is illustrated by two Matlab functions given in the paper. Despite its simplicity, the time complexity of this paradigm is found to be high. Consequently, the third method, which is evolved from the preceding one, reduces the time complexity significantly with the utilization of a geometric range search method. This technique, which has a considerable margin for improvement, is found to be suitable to be used as a part of the real-time motion command generator for CNC applications. Unlike the previous schemes, the final approach uses polygon operations to generate such curves. The run-time of this technique is highly governed by the complexity of the polygon overlay algorithm selected. The paper analyzes the complexity of each technique. Finally, the presented methods are evaluated (in terms of run-time and geometric accuracy) via two test cases where most CAD/CAM packages fail to yield acceptable results.     

Direct command generation for CNC machinery based on data compression techniques

This paper presents a direct command generation technique for digital motion control systems. In this paradigm, higher-order differences of a given trajectory (i.e. position) are calculated and the resulting sequence is compacted via data compression techniques. The overall method is capable of generating trajectory data at variable rates in forward- and reverse-directions with the utilization of a linear interpolator. As a part of the command generation scheme, the paper also proposes a new data compression technique titled ΔY10. Apart from this new method, the performances of the proposed generator employing different compression algorithms (such as Huffman coding, Arithmetic coding, LZW, and run length encoding) are also evaluated through three test cases. The paper illustrates that the ΔY10 technique, which is suitable for real-time hardware implementation, exhibits satisfactory performance in terms of data compaction achieved in the test cases considered.