Model Validation for Bridge-Road-Vehicle Dynamic Interaction System

The dynamic response of highway bridges subjected to moving truckloads has been observed to be dependent on (1) dynamic characteristics of the bridge; (2) truck configuration, speed, and lane position on the bridge; and (3) road surface roughness profile of the bridge and its approach. Historically, truckloads were measured to determine the load spectra for girder bridges. However, truckload measurements are either made for a short period of time [for example, weigh-in-motion (WIM) data] or are statistically biased (for example, weigh stations) and cost prohibitive. The objective of this paper is to present results of a 3D computer-based model for the simulation of multiple trucks on girder bridges. The model is based on the grillage approach and is applied to four steel girder bridges tested under normal truck traffic. Actual truckload data collected using a discrete bridge WIM system are used in the model. The data include axle loads, truck gross weight, axle configuration, and statistical data on multiple presence (side by side or following). The results are presented as a function of the static and dynamic stresses in each girder and compared with code provisions for dynamic load factor. The study provides an alternate method for the development of live-load models for bridge design and evaluation.     

Assessing the potential of renewable energy sources in Turkey

To meet Turkey’s growing energy demand, the installed electric power capacity of 27.8 GW in 2001 has to be doubled by 2010 and increased fourfold by 2020. The difference between Turkey’s total primary energy supply (TPES) of from its own sources and total final consumption (TFC) is projected grow from 1 quad (1.06–2.06) in 1999 to 5.71 quads (2.79–8.5) in 2020 (1 QUAD=293.071 TWh). Turkey’s limited amount of fossil fuels has a present average ratio of proved reserves of 97.38 quads to production rate of 3.2 quads yr⁻¹ of about 30 years. Turkey’s reliance on fossil fuel-based energy systems to meet the growing demand is most likely to exacerbate the issues of energy insecurity, national environmental degradation, and global climate change in increasing proportions. Economically-feasible renewable energy potential in Turkey is estimated at a total of ca. 1.69 quads yr⁻¹ (495.4 TWh yr⁻¹) with the potential for 0.67 quads yr⁻¹ (196.7 TWh yr⁻¹) of biomass energy, 0.42 quads yr⁻¹ (124 TWh yr⁻¹) of hydropower, 0.35 quads yr⁻¹ (102.3 TWh yr⁻¹) of solar energy, 0.17 quads yr⁻¹ (50 TWh yr⁻¹) of wind energy, and 0.08 quads yr⁻¹ (22.4 TWh yr⁻¹) of geothermal energy. Pursuit and implementation of sustainability-based energy policy could provide about 90 and 35% of Turkey’s total energy supply and consumption projected in 2010, respectively. Utilization of renewable energy technologies for electricity generation would necessitate about 23.2 Mha (29.8%) of Turkey’s land resources.     

The role of diagnostic laparoscopy in treatment of penetrating injuries of the lower thoracic wall and anterior abdominal wall

Penetrating injuries of the lower thoracic wall and anterior abdominal wall cause difficulties in the decision for laparotomy. For gunshot wounds laparotomy without further investigations is in most cases justified, but in other penetrating traumata one should use every diagnostic modality to prevent unacceptably high negative laparotomy rates. We performed diagnostic laparoscopy (DL) on 39 patients with penetrating injuries of the anterior abdominal wall and/or lower thoracic wall. Of these 39 patients, 25 had negative and 14 positive results. We had only one false-negative finding. No false-positive result occurred. We think that DL is a very reliable diagnostic tool which requires a relatively high technology.     

Grafting of poly(ethylene terephthalate) fibers with methacrylic acid using benzoyl peroxide

The graft copolymerization of methacrylic acid onto poly(ethylene terephthalate) fibers, by the aid of benzoyl peroxide, have been investigated. The graft yield increased up to 85°C, and then decreased with the further increase in temperature. The maximum graft yield was obtained at benzoyl peroxide concentration of 4.0 × 10^?3 mol/L. The increase in the concentration of monomer was found to increase the graft yield. The change in the graft yield was followed by the experiments carried out using different water/solvent mixtures. Also, the change in the properties of polye (thylene terephthalate) fibers grafted with methacrylic acid such as moisture regain, density, and diameter were investigated.     

Cancer patients psychological adjustment and perception of illness: cultural differences between Belgium and Turkey

Little is known about cultural differences in psychological adjustment and perception of illness (PI) during medical procedures in general and radiotherapy in particular. This study compares a Turkish (TP) and a French speaking Belgian (BP) population. A group of 296 consecutive patients attending the radiotherapy clinic of Institut Jules Bordet, Brussels, (n = 172) and Oncology Institute, Capa-Istanbul, (n = 124) were interviewed and assessed by a symptom checklist, the SCL-90-R, at the beginning and at the end of the radiotherapy. PI, derived from a semi-structured interview, was assessed at the beginning of radiotherapy by a five-point observer-rating scale derived from the Omega Vulnerability Rating Scale. Differences in SCL-90-R scores, taking into account country, age, gender, level of education and PI as potential explanatory variables, have been tested by a multivariate analysis of variance with a design of repeated measures using the SCL-90-R scores as dependent variables. Mainly a time effect and a country effect have been found. Some interactions between both effects have also been found. Globally, all the SCL-90-R scores decrease between the beginning and the end of the radiotherapy. The effect of country is noticeable for most of the SCL-90-R components, with higher scores in the BP, except for the positive symptom total score where the TP showed higher scores. The interaction between country and time is not significant, the scores of both the BP and TP decreasing over time, except for somatization scores (P < 0.001) where the scores of the BP were stable over time while the scores of the TP decreased considerably, and for paranoid ideation scores (P = 0.001) where the scores of the BP decreased while the scores of the TP increased. Results showed a higher rate of correct perception in the BP compared to the TP (P = 0.0001). A PI effect has been found for somatization (P = 0.02), anxiety (P = 0.01) and Global Severity Index scores (P = 0.05), with higher mean scores for the "correct perception" category. No interaction with time was found. A significant interaction effect between country and PI has been found for anxiety scores with higher scores in the correct perception category in the BP and in the "denial of implications" category in the TP (P < 0.001). Results highlight cultural differences in psychological adjustment and/or in the responses to self-report questionnaires: greater weight was given to items by the BP, more numerous items were scored by the TP, and greater weight was given to the somatization subscale compared to the psychological subscales by the TP. This study suggests that psychosocial distress is expressed differently in Belgium and Turkey, where patients express mostly somatic complaints. Finally PI, a culture-dependent factor, appears to influence psychological adjustment very differently, a correct perception of illness leading to more anxiety in the BP compared to the TP.     

Is cheating a human function? The roles of presence,state hostility,and enjoyment in an unfair video game

In sports and board games, when an opponent cheats, the other players typically greet it with disdain, anger, and disengagement. However, work has yet to fully address the role of the computer cheating in video games. In this study, participants played either a cheating or a non-cheating version of a modified open-source tower-defense game. Results indicate that when a computer competitor cheats, players perceive the opponent as being more human. Cheating also increases player aggravation and presence, but does not affect enjoyment of the experience. Additionally, players that firmly believed that their opponent was controlled by the computer exhibited significantly less state hostility compared to players that were less certain of the nature of their competitor. Game designers can integrate subtle levels of cheating into computer opponents without any real negative responses from the players. The results indicate that minor levels of cheating might also increase player engagement with video games.     

Surface modification of polysulfone based hemodialysis membranes with layer by layer self assembly of polyethyleneimine/alginate-heparin: a simple polyelectrolyte blend approach for heparin immobilization

This study intends to improve blood compatibility of polysulfone (PSF) membranes by generating a nonthrombogenic surface through heparin immobilization. To achieve this task, the support membrane prepared from a blend of PSF and sulfonated polysulfone (SPSF) was modified with layer by layer (LBL) deposition of polyethyleneimine (PEI) and alginate (ALG) and heparin blended with ALG was immobilized only on the outermost surface of the LBL assembly. The results have shown that the adsorption of human plasma proteins and platelet activation on the LBL modified membranes decreased significantly compared with the unmodified PSF and PSF-SPSF blend membranes. Furthermore, blending ALG with a small amount of heparin remarkably prolonged the APTT values of heparin free PEI/ALG coated membranes. It is envisaged that the use of a blend of HEP and ALG only in the terminating layer of the LBL assembly can be an economical and alternative modification technique to create nonthrombogenic surfaces.     

Multi-dimensional clearing functions for aggregate capacity modelling in multi-stage production systems

Nonlinear clearing functions have been proposed in the literature as metamodels to represent the behaviour of production resources that can be embedded in optimisation models for production planning. However, most clearing functions tested to date use a single-state variable to represent aggregate system workload over all products, which performs poorly when product mix affects system throughput. Clearing functions using multiple-state variables have shown promise, but require significant computational effort to fit the functions and to solve the resulting optimisation models. This paper examines the impact of aggregation in state variables on solution time and quality in multi-item multi-stage production systems with differing degrees of manufacturing flexibility. We propose multi-dimensional clearing functions using alternative aggregations of state variables, and evaluate their performance in computational experiments. We find that at low utilisation, aggregation of state variables has little effect on system performance; multi-dimensional clearing functions outperform single-dimensional ones in general; and increasing manufacturing flexibility allows the use of aggregate clearing functions with little loss of solution quality.