Investigation of fatigue properties of shot peened and plasma nitrocarburized P/M FC0205 steel

One of the widely used powder metal materials in automotive industry, which is copper steel FC 0205 (Fe + 2% Cu + 0.5% C), was used in this study. The pressed samples has been prepared at the compression pressure of 680 MPa and sintered in conventional furnace at 1120°C for 30 minutes. The samples with 7 Mg/m³ densities were used as fatigue and shot peening processes. Shot peening were applied with 20A and 32A and the others were not peened. Plasma nitrocarburizing process was performed at 555°C for 2 hours under 600–900 Pa pressure. Fatigue tests were conducted at room temperature on a rotating bending type fatigue test device. It was determined that shot peening should be used where increased fatigue strength is needed, and plasma nitrocarburizing should be preferred where surface hardness is required, and plasma nitrocarburizing after shot peening process is much more useful.     

Assessing effect of electrode configuration on the efficiency of electrokinetic remediation by sequential extraction analysis

The electroremediation experiments were conducted on artificially polluted soils by introducing a single metallic contaminant (Pb, Zn and Cu) and multiple metallic contaminants (Pb+Zn+Cu). Based on sequential extraction results, it was observed that the removal efficiencies of lead, zinc and copper vary depending on types of contamination. When the soil was contaminated only by lead, the removal efficiency was found to be 48%. However, the removal efficiency of lead decreased to 32% when the soil was contaminated by the combination of lead, zinc and copper. Similar results were observed for zinc and copper. The corresponding removal efficiency values for zinc and copper were 92% and 37%, and 34% and 31%, respectively. Effects of electrode geometry on the removal efficiency of metals were investigated by constructing a multiple anode arrangement. In this arrangement, the electrokinetic unit consists of three cylinders, which lie one inside the other, and the soil was placed in the middle cylinder. The central cylinder was the cathode well and the outer cylinder was the anode well, where eight identical anode electrodes were placed in octagonal with respect to the cathode electrode. By using this electrode arrangement in removal of metals from the soil contaminated with the combination of three metals (Pb+Zn+Cu), the removal efficiencies of lead, zinc and copper were found to be 29%, 18% and 18%, respectively. As it can be seen, these numerical values are much lower than the values that were obtained when the traditional two-plate electrode arrangement used in the electroremediation experiments (32%, 37% and 31%).     

Congenital hypodontia of maxillary lateral incisors in association with coloboma of the iris and hypomaturation type of amelogenesis imperfecta in a large kindred

This article presents a step-by-step approach to working with family-generated metaphor in family therapy. Although the use of therapist-generated "therapeutic metaphors" has been widely advocated and practiced for many years now, less attention has been paid to the metaphors used by family members. We argue that the family's metaphors are a neglected linguistic resource in family therapy. Highlighting and validating these metaphors produces a therapeutic conversation in which the voices of family members are heard more clearly by the therapist, and the families' own imaginative energies are engaged in defining and pursuing the goals of therapy. Several case examples illustrate the use of this approach with children of various ages.     

The role of dislocation-induced scattering in electronic transport in GaxIn1-xN alloys

ABSTRACT: Electronic transport in unintentionally doped GaxIn1-xN alloys with various Ga concentrations (x = 0.06, 0.32 and 0.52) is studied. Hall effect measurements are performed at temperatures between 77 and 300 K. Temperature dependence of carrier mobility is analysed by an analytical formula based on two-dimensional degenerate statistics by taking into account all major scattering mechanisms for a two-dimensional electron gas confined in a triangular quantum well between GaxIn1-xN epilayer and GaN buffer. Experimental results show that as the Ga concentration increases, mobility not only decreases drastically but also becomes less temperature dependent. Carrier density is almost temperature independent and tends to increase with increasing Ga concentration. The weak temperature dependence of the mobility may be attributed to screening of polar optical phonon scattering at high temperatures by the high free carrier concentration, which is at the order of 1014 cm-2. In our analytical model, the dislocation density is used as an adjustable parameter for the best fit to the experimental results. Our results reveal that in the samples with lower Ga compositions and carrier concentrations, alloy and interface roughness scattering are the dominant scattering mechanisms at low temperatures, while at high temperatures, optical phonon scattering is the dominant mechanism. In the samples with higher Ga compositions and carrier concentrations, however, dislocation scattering becomes more significant and suppresses the effect of longitudinal optical phonon scattering at high temperatures, leading to an almost temperature-independent behaviour.     

Soybean oil based thermoset networks via photoinduced CuAAC click chemistry

A simple method based on photochemically induced copper(I)‐catalyzed azide ? alkyne cycloaddition click reaction (CuAAC ) is developed for the preparation of thermoset networks from soybean oils as renewable resources. The incorporation of clickable azide and alkyne functionalities into epoxidized soybean oils is done by simultaneous ring‐opening reactions between the epoxide group of soybean oils and sodium azide and propargyl alcohol, respectively. The obtained azide‐ and alkyne‐functionalized soybean oils are easily transformed crosslinked networks via the photoinduced CuAAC reaction in ambient conditions. The introduction of additional multifunctional monomers in the formulation not only increases the crosslinking density but also improves the mechanical properties of the thermoset material obtained. In a comparison of the two formulations, the sample containing additional multifunctional monomers has a higher glass transition temperature, storage modulus and damping properties. © 2017 Society of Chemical Industry     

Image-Based Rendering Using Parameterized Image Varieties

This paper addresses the problem of characterizing the set of all images of a rigid set of m points and n lines observed by a weak perspective or paraperspective camera. By taking explicitly into account the Euclidean constraints associated with calibrated cameras, we show that the corresponding image space can be represented by a six-dimensional variety embedded in R^2(m+n) and parameterized by the image positions of three reference points. The coefficients defining this parameterized image variety (or PIV for short) can be estimated from a sample of images of a scene via linear and non-linear least squares. The PIV provides an integrated framework for using both point and line features to synthesize new images from a set of pre-recorded pictures (image-based rendering). The proposed technique does not perform any explicit three-dimensional scene reconstruction but it supports hidden-surface elimination, texture mapping and interactive image synthesis at frame rate on ordinary PCs. It has been implemented and extensively tested on real data sets.     

Epidemic-based reliable and adaptive multicast for mobile ad hoc networks

An emerging approach to distributed systems exploits the self-organization, autonomy and robustness of biological epidemics. In this article, we propose a novel bio-inspired protocol: EraMobile (Epidemic-based Reliable and Adaptive Multicast for Mobile ad hoc networks). We also present extensive performance analysis results for it. EraMobile supports group applications that require high reliability. The protocol aims to deliver multicast data reliably with minimal network overhead, even under adverse network conditions. With an epidemic-based multicast method, it copes with dynamic and unpredictable topology changes due to mobility. Our epidemic mechanism does not require maintaining any tree- or mesh-like structure for multicasting. It requires neither a global nor a partial view of the network, nor does it require information about neighboring nodes and group members. In addition, it substantially lowers overhead by eliminating redundant data transmissions. Another distinguishing feature is its ability to adapt to varying node densities. This lets it deliver data reliably in both sparse networks (where network connectivity is prone to interruptions) and dense networks (where congestion is likely). We describe the working principles of the protocol and study its performance through comparative and extensive simulations in the ns-2 network simulator.     

Structural changes driven by e-petitioning technology: changing the relationship between the central government and local governments

ABSTRACT

e-Petitioning is a type of information and communication technology for development that can be used by citizens to express their voices in society. Although much work is focused on government-citizen relationships, little is known about whether and, if so, how e-petitions technology might result in structural transformations in public administration. In this study, we investigated the effects of an e-petitioning system in the Turkish public administration from neo-institutional and transaction cost perspectives. In contrast to the expectation of reducing transaction costs due to ICTs use, the transaction costs increased. The changes have further strengthened the central government by transforming the current tutelary relationship into a more hierarchical structure. The change is not driven by lowering transaction costs; instead, the change mirrors the power structures. The use of technology changed the structures in such a way that political power structures are reinforced while empowering the citizens to make their voices heard.     

PCR‐RFLP and DAMD‐PCR genotyping for Salvia species

BACKGROUND: Identification of genotypes in Salvia is complicated owing to the morphological similarity and common occurrence of natural hybridisation within Salvia species. Species‐ and genotype‐specific DNA markers are very useful for plant identification, breeding and preservation programmes and can also provide a general overview on the prediction of plant essential oil yield. RESULTS: Polymerase chain reaction restriction fragment length polymorphism (PCR‐RFLP) was used for identification of species‐specific chloroplast and mitochondrial organelle DNA markers, and directed amplification of minisatellite DNA polymerase chain reaction (DAMD‐PCR) was used for genotyping of plant materials. Application of PCR‐RFLP resulted in species‐specific DNA markers, and use of DAMD‐PCR resulted in reproducible DNA patterns that are useful in Salvia genetic studies. Multivariate cluster analysis and principal coordinate analysis indicated that there were relationships between DNA marker patterns and essential oil yields at the species level. CONCLUSION: Results showed that genetic variations in Salvia are wide, and DNA patterns of relatedness among plant species appeared to correlate with essential oil yields. Further studies are required to confirm the application of PCR‐RFLP and DAMD‐PCR markers for selection of Salvia species with higher essential oil yield. Copyright © 2008 Society of Chemical Industry