Microstructure and Wear Behaviour of 17-4 Precipitation Hardening Stainless Steel with Various Ti Content

Powder Metallurgy and Metal Ceramics - In this study, the wear behaviour of aged 17-4 PH SS (precipitation hardening stainless steel) that contains 0.5, 1, 1.5, and 2% of Ti was examined. The mixed...     

Growth of NBT template particles through topochemical microcrystal conversion and their structural characterization

In this study, uniform rectangular plate‐like perovskite Na_0.5Bi_0.5TiO₃ templates were obtained by molten salt synthesis method in three steps. Perovskite plate‐like Na_0.5Bi_0.5TiO₃ templates were synthesized from bismuth‐layered Na_0.5Bi_4.5Ti₄O₁₅ by topochemical microcrystal conversion method at the third and final step. The most important point was that the plate‐like morphology remained as desired, but templates were obtained in cubic perovskite structure. The Na₂CO₃ excess in the third step was the main controlling parameter. The crystalline orientation of the particles was investigated by electron backscatter diffraction analysis. The results indicated that the particles are single crystalline in nature. In the case of the 90 mol% excess of the stoichiometric Na₂CO₃ ratio, the NBT platelets had highly regular, rectangular prismatic morphology and single‐crystal nature. The structure was also confirmed through high‐resolution transmission electron microscope and selected area electron diffraction analysis.     

Identifying significant predictors of injury severity in traffic accidents using a series of artificial neural networks

Understanding the circumstances under which drivers and passengers are more likely to be killed or more severely injured in an automobile accident can help improve the overall driving safety situation. Factors that affect the risk of increased injury of occupants in the event of an automotive accident include demographic or behavioral characteristics of the person, environmental factors and roadway conditions at the time of the accident occurrence, technical characteristics of the vehicle itself, among others. This study uses a series of artificial neural networks to model the potentially non-linear relationships between the injury severity levels and crash-related factors. It then conducts sensitivity analysis on the trained neural network models to identify the prioritized importance of crash-related factors as they apply to different injury severity levels. In the process, the problem of five-class prediction is decomposed into a set of binary prediction models (using a nationally representative sample of 30358 police-recorded crash reports) in order to obtain the granularity of information needed to identify the "true" cause and effect relationships between the crash-related factors and different levels of injury severity. The results, mostly validated by the findings of previous studies, provide insight into the changing importance of crash factors with the changing injury severity levels.     

The contribution of wind-hydro pumped storage systems in meeting Turkey's electric energy demand

Renewable energy resources have played an important role to meet increasing energy demand in the world. Among the renewable energy resources, especially, wind energy is of interest due to some advantages, such as being clean, environmental friendly etc. However, the intermittent nature of wind creates several problems to the power system operation and new approaches based on the combined use of wind power and energy storage technologies need to be developed. One of these combined systems is wind-hydro pumped storage systems. In this paper, hydropower and wind energy potential of Turkey are investigated in details. Besides, the importance and the necessity of wind-hydro pumped storage systems for Turkey are comprehensively examined and finally, the contribution of wind-hydro pumped storage systems is emphasized in meeting Turkey's electric energy demand.     

Analysis of cancer data: a data mining approach

Abstract: Even though cancer research has traditionally been clinical and biological in nature, in recent years data driven analytic studies have become a common complement. In medical domains where data and analytics driven research is successfully applied, new and novel research directions are identified to further advance the clinical and biological studies. In this research, we used three popular data mining techniques (decision trees, artificial neural networks and support vector machines) along with the most commonly used statistical analysis technique logistic regression to develop prediction models for prostate cancer survivability. The data set contained around 120 000 records and 77 variables. A k-fold cross-validation methodology was used in model building, evaluation and comparison. The results showed that support vector machines are the most accurate predictor (with a test set accuracy of 92.85%) for this domain, followed by artificial neural networks and decision trees.     

An analytic approach to better understanding and management of coronary surgeries

Demand for high-quality, affordable healthcare services increasing with the aging population in the US. In order to cope with this situation, decision makers in healthcare (managerial, administrative and/or clinical) need to be increasingly more effective and efficient at what they do. Along with expertise, information and knowledge are the other key sources for better decisions. Data mining techniques are becoming a popular tool for extracting information/knowledge hidden deep into large healthcare databases. In this study, using a large, feature-rich, nationwide inpatient databases along with four popular machine learning techniques, we developed predictive models; and using an information fusion based sensitivity analysis on these models, we explained the surgical outcome of a patient undergoing a coronary artery bypass grafting. In this study, support vector machines produced the best prediction results (87.74%) followed by decision trees and neural networks. Studies like this illustrate the fact that accurate prediction and better understanding of such complex medical interventions can potentially lead to more favorable outcomes and optimal use of limited healthcare resources.     

The releases of agrochemicals from radiation induced acrylamide/crotonic acid hydrogels

Summary The aim of this work was to test the application of new copolymeric poly(acrylamide/crotonic acid) (AAm/CA) hydrogels to agrochemicals (sodium 2,2 dichloropropionate (dalapon), ammonium nitrate, potassium nitrate and ammonium sulfate) releases. AAm/CA hydrogels containing agrochemicals is prepared by two different composition of crotonic acid and two different γ-rays doses. The herbiside such as sodium 2,2 dichloropropionate (dalapon) and fertilizers such as ammonium nitrate, potassium nitrate and ammonium sulfate were trapped in the gels by including it in the feed mixture of radiation polymerization. The equilibrium swelling degree in water was between 1020% and 1840%. The swelling kinetics of the hydrogels were studied at 25 °C, and the initial swelling rate, swelling rate constant, maximum swelling, diffusional exponent and diffusion coefficient of the process were obtained. The concentration of the released of agrochemicals from the hydrogels was determined by conductivity measurements. The initial releasing rate, release rate constant, maximum concentration of releasing agrochemicals were calculated. As a result, if AAm/CA hydrogels containing agrochemicals were swelled in water, release of agrochemicals was increased with the raising of crotonic acid quantities in the hydrogel and γ-rays doses. Received: 28 August 1998/Accepted: 24 September 1998     

Swelling and dye adsorption properties of radiation induced N-vinyl-2-pyrrolidone/acrylonitrile hydrogels

Summary Swollen hydrogels were prepared by γ-radiation copolymerization of N-vinyl-2-pyrrolidone and acrylonitrile. The influence of radiation dose and feed composition on the swelling properties, diffusional behavior of water and diffusion coefficients of the hydrogel systems were examined. N-vinyl-2-pyrrolidone/acrylonitrile hydrogels were swollen in the range 50–850%. Water diffusion to the hydrogels generally was a non-Fickian type diffusion. The hydrogel were used in the studies of adsorption of some water soluble dye such as basic blue 9, tetraethyl rhodamine, xylidine ponceau 2R, indigo carmine, helianthin and erythrosine, and of a vitamin riboflavin (Vitamin B₂). Received: 9 June 1998/Revised version: 23 July 1998/Accepted: 23 July 1998     

Interaction of some cationic dyes with acrylamide/itaconic acid hydrogels

Acrylamide/itaconic acid (AAm/IA) hydrogels prepared by irradiating with γ radiation were used in experiments on uptake of some cationic dyes such as union green B (UG-B), basic blue 17 (BB-17), basic red 2 (BR-2), and lauths violet (LV). Adsorption of the cationic dyes onto AAm/IA hydrogels is studied by batch adsorption technique at 25°C. In the experiments of the adsorption, Langmiur type adsorption in the Giles classification system was found. Some binding and thermodynamic parameters for AAm/IA hydrogel-dye systems were calculated by using Klotz method. Adsorption studies indicated that monolayer coverages of AAm/IA hydrogel by these dyes were increased with following order BB-17 > UG-B > BR-2 > LV. © 1996 John Wiley & Sons, Inc.     

Equilibrium, kinetic and thermodynamic studies on the adsorption of phenol onto chitin

The adsorption of phenol onto chitin, a naturally occurring material was studied as a function of initial pH, temperature and initial phenol concentration. The highest phenol adsorption capacity was determined as 21.5 mgg(-1) for 300 mgdm(-3) initial phenol concentration at pH 1.0 and 40 degrees C. Adsorption data were well described by the Freundlich Model, although they could be modeled by the Langmuir equation. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data. The pseudo-second-order kinetic model provided the best correlation of the experimental data compared to the pseudo-first-order model. The thermodynamic constants of the adsorption process; DeltaG degrees , DeltaH degrees and DeltaS degrees were evaluated as -19.4 kJmol(-1) (at 40 degrees C), 10.2 kJmol(-1) and 0.093 kJmol(-1)K(-1), respectively. These showed that adsorption of phenol on chitin was endothermic and spontaneous.