Sorptive Stress Estimation: An Important Key to the Mechano-Sorptive Effect in Wood

The mechano-sorptive effect (MSE) can be classified as a veryinteresting, but not yet completely explained phenomenon of woodbehaviour. We therefore decided to try to discover its most relevantmechanisms, by conducting two independent series of measurements:accurate measurements of bending deflections on small, clear specimensof spruce wood in changeable climate conditions; and average moisturecontent (MC) in three parts of the cross-section of unloaded dummysamples. The paper emphasises on the sorptive part of MSE. A computersimulation of the wetting experiment is done to determine the space andtime-dependent MC field in the cross-section of the sample. Using aso-called inverse problem identification method, where the equivalenceof the computed and measured responses of the numerical model and realsample is imposed, we identified unknown material properties. Thesolution of the inverse problem enabled us simultaneously to estimatethe moisture diffusion coefficients and to determine the MC field. Twokinds of boundary conditions were used in simulations. To estimate themagnitude of sorption stresses a numerical analysis using Finite ElementMethod (FEM) was done. The sorptive stresses resulting from thenonhomogeneous MC distribution in the sample were obtained. The decisivefactor is the gradient of moisture content and resulting sorptivestresses must be taken into account because their magnitude is of thesame order as the load induced bending stresses. Our experiments and thecalculations following enabled us to conclude that the reason for MSbehaviour could be the simultaneous action of permanent load stressesand the transient triaxial sorptive stress state.     

Overall equipment effectiveness when production speeds and stoppage durations are uncertain

Evaluation of manufacturing equipment performance has been very important in production-related functions such as planning, scheduling, and maintenance. Nevertheless, low accuracy of performance measurements can mislead decision makers. In this study, overall equipment effectiveness (OEE) is considered as a performance indicator of manufacturing equipment. In practice, components of OEE may consist of uncertainty due to manual or semi-automatic measurement systems. As a consequence, true performance of equipment may be masked by the uncertainty of measurements. In this study, two types of uncertainty are considered in production speed and stoppage duration measurements, which are used in calculating OEE components. When the measurements have uncertainty due to use of linguistic terms or some minor stoppages, idling, or speed losses being ignored, fuzzy arithmetic is used as a method to handle uncertainty. In some low accuracy cases, best guess interval estimates of operators may better reflect the state than just providing a point estimate. For such cases, interval arithmetic is used as a method to handle uncertainty. Implementation of the methods are illustrated using two real-world examples and a software is provided for practitioners. Proposed methods help making better informed decisions using OEE under measurement uncertainty of production speed and stoppage durations.     

Prediction of earthquake damage to urban water distribution systems: a case study for Denizli,Turkey

Prediction of damage to water supply lines during an earthquake is a critical part of seismic planning. This study evaluates the performance of the water supply system in Denizli, Turkey, in the event of an M6, M6.3, M6.5 and M7 earthquake associated with the Pamukkale and Karakova-Akhan Faults. The relative effects of transient ground deformations and permanent ground deformations based on maps of liquefiable soil and zones of predicted lateral ground displacements are compared. The relative effects of the different magnitude earthquakes and pipeline damage relationships on the pipeline performance following a seismic event are assessed.     

The Bauschinger effect in the supercooled austenite of SAE 52100 steel

During the heat treatment and the welding of steel components, the interactions between the thermal and phase transformation strains result in cyclic loading of the component, which often results in plastic deformation. Although this has long been a well-known fact, the cyclic hardening behavior of supercooled austenite was not investigated up to now. In this study, tension–compression tests were performed on the supercooled austenite of SAE 52100 ball bearing steel at several temperatures using Gleeble3500® thermomechanical testing machine. The results were compared with conventional hardening models used in heat treatment and welding simulation. The results indicate that the metastable austenite exhibits a complicated cyclic hardening behavior that can only be partially reproduced by commercial simulation software. In the outlook, it is concluded that more complicated cyclic hardening models should be implemented for better prediction of distortion and residual stresses after heat treatment or welding.     

Modified gold surfaces by 6-(ferrocenyl)hexanethiol/dendrimer/gold nanoparticles as a platform for the mediated biosensing applications

An electrochemical biosensor mediated by using 6-(Ferrocenyl) hexanethiol (FcSH) was fabricated by construction of gold nanoparticles (AuNPs) on the surface of polyamidoamine dendrimer (PAMAM) modified gold electrode. Glucose oxidase (GOx) was used as a model enzyme and was immobilized onto the gold surface forming a self assembled monolayer via FcSH and cysteamine. Cyclic voltammetry and amperometry were used for the characterization of electrochemical response towards glucose substrate. Following the optimization of medium pH, enzyme loading, AuNP and FcSH amount, the linear range for the glucose was studied and found as 1.0 to 5.0 mM with the detection limit (LOD) of 0.6 mM according to S/N = 3. Finally, the proposed Au/AuNP/(FcSH + Cyst)/PAMAM/GOx biosensor was successfully applied for the glucose analysis in beverages, and the results were compared with those obtained by HPLC.     

Fracturing Rate Effect and Creep in Microplane Model for Dynamics

The formulation of microplane model M4 in Parts I and II is extended to rate dependence. Two types of rate effect in the nonlinear triaxial behavior of concrete are distinguished: (1) Rate dependence of fracturing (microcrack growth) associated with the activation energy of bond ruptures, and (2) creep (or viscoelasticity). Short-time linear creep (viscoelasticity) is approximated by a nonaging Maxwell spring-dashpot model calibrated so that its response at constant stress would be tangent to the compliance function of model B3 for a time delay characteristic of the problem at hand. An effective explicit algorithm for step-by-step finite-element analysis is formulated. The main reason that the rate dependence of fracturing must be taken into account is to simulate the sudden reversal of postpeak strain softening into hardening revealed by recent tests. The main reason that short-time creep (viscoelasticity) must be taken into account is to simulate the rate dependence of the initial and unloading stiffness. Good approximations of the rate effects observed in material testing are achieved. The model is suitable for finite-element analysis of impact, blast, earthquake, and short-time loads up to several hours duration.     

Renal artery embolization in severe nephrotic syndrome

Introduction Severe nephrotic syndrome is associated with increased morbidity and mortality. Renal artery embolization (RAE) has been used in a number of renal diseases such as renal tumors, arteriovenous fistulas etc. However, data regarding benefits of RAE in patients with symptomatic severe proteinuria is limited. We decided to evaluate role of RAE in the setting of severe symptomatic nephrotic syndrome. Methods Eight patients who had undergone transcatheter renal artery embolization with polyvinyl alcohol (PVA) were included. Clinico‐demographic characteristics as well as baseline laboratory data including level of proteinuria, serum albumin, C‐reactive protein and LDL cholesterol levels were recorded for each patient. After RAE, outpatient clinic control laboratory values were also assessed. Findings All patients except one underwent bilateral RAE (four simultaneous or three sequential). Two patients experienced postembolization syndrome characterized by flank pain, fever, and leukocytosis, which was self‐limited and responded to analgesics in all patients. There was no technical complications associated with RAE procedure. All patients became anuric except one. Serum albumin levels increased and serum LDL‐cholesterol levels decreased considerably in treated patients. Discussion Renal artery embolization with the purpose of amelioration in nephrotic syndrome complications was effective and free of major technical complications in our patients.     

Synthesis of beta silicon carbide powders using carbon coated fumed silica

The synthesis of beta silicon carbide (-SiC) powders by carbothermic reduction of carbon coated silica and silica mixed with carbon black was investigated. The production of -SiC powders by using carbon coated silica consists of two steps. The first step is to prepare the carbon coated silica precursor by coating fumed silica particles with carbon by pyrolytic cracking of a hydrocarbon gas (C3H6). This provides intimate contact between the reactants and yields a better distribution of carbon within the fumed silica. Fumed silica was also mechanically mixed with carbon black for comparison. Both starting mixtures were reacted in a tube furnace for 2 h at temperatures of 1300°C to 1600°C in 1 l min-1 flowing argon. The reaction products were characterized using weight loss data, X-ray diffraction (XRD), a BET surface area analyser, oxygen and free carbon analysis and transmission electron microscopy (TEM). The carbon coating process resulted in a more complete reaction, purer product and high yield SiC powders with very little agglomeration at temperatures of 1500°C and 1600°C. The -SiC powders produced at 1600°C for 2 h in argon gas flow have oxygen content of 0.3 wt%, a very fine particle size 0.1–0.3 m and uniform shape. © 1998 Chapman & Hall     

An information theoretic approach to camera control for crowded scenes

Navigation and monitoring of large and crowded virtual environments is a challenging task and requires intuitive camera control techniques to assist users. In this paper, we present a novel automatic camera control technique providing a scene analysis framework based on information theory. The developed framework contains a probabilistic model of the scene to build entropy and expectancy maps. These maps are utilized to find interest points which represent either characteristic behaviors of the crowd or novel events occurring in the scene. After an interest point is chosen, the camera is updated accordingly to display this point. We tested our model in a crowd simulation environment and it performed successfully. Our method can be integrated into existent camera control modules in computer games, crowd simulations and movie pre-visualization applications.     

Uniaxial tensile properties of TiO2 coated single wool fibers by sol‐gel method: The effect of heat treatment

Single wool fibers were coated with TiO₂ by using the sol‐gel method. The uniaxial tensile properties of TiO₂ coated single wool fibers heated at different temperatures from 25 to 200°C were investigated and compared with those of uncoated single wool fibers. It was observed that the shape of the stress–strain curve of TiO₂ coated wool fibers became the same as uncoated wool fibers and showed a similar tendency of change to uncoated wool fibers with increasing temperature. But, the TiO₂ coated wool fibers obtained higher rigidity than uncoated wool fibers and up to their rupture points; they obtained higher stress levels in three deformation regions in the stress–strain curves, which indicates stronger wool fibers. Although the breaking extension of TiO₂ coated wool fibers decreased little by about 8%, the Young's modulus of TiO₂ coated wool fibers increased significantly by 19%, which was caused mostly by an increment in the stiffness of the cuticle layer of the wool fiber, and remained relatively higher than that of uncoated wool fibers after heat treatments. Structural changes in both uncoated and TiO₂ coated single wool fibers due to thermal effect, which caused the changes in the uniaxial tensile properties and the thermal behaviors of these fibers were discussed by using spectroscopic and thermal analysis methods in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 898‐907, 2013