Correlating cutting efficiency and debris retention of endodontic files to their design features using AutoCAD measurements

This study aims at evaluating the deformation changes on three types of root canal rotary instruments with different designs; the Pro-Taper Universal, the V-Taper, and the Liberator systems after clinical use. Measurements were made before and after the instruments were used for treating four human root canals by developing stereo-microscopic images for a number of instruments from the three systems at the same position. All images were transformed to AutoCAD to evaluate changes in measurements before and after use. The results showed that the majority of the tested instruments were subjected to significant deformations along the length of the working parts of the instruments. These deformations were only detected by the AutoCAD program but went unnoticed by either visual or microscopic examinations. The results suggest that AutoCAD could be a ground of developing a chair side “computer image analysis program” to predict and justify discarding of a piece before or during operation. In addition, considerations should be given to the material of construction and new approaches of ion implants, such as electro-polishing, that could improve or at least assist in enhancing the wear resistance of the instruments against the dentine surface.     

Secure multicast routing protocols in mobile ad‐hoc networks

A mobile ad‐hoc network (MANET) is a collection of autonomous nodes that communicate with each other by forming a multi‐hop radio network. Routing protocols in MANETs define how routes between source and destination nodes are established and maintained. Multicast routing provides a bandwidth‐efficient means for supporting group‐oriented applications. The increasing demand for such applications coupled with the inherent characteristics of MANETs (e.g., lack of infrastructure and node mobility) have made secure multicast routing a crucial yet challenging issue. Recently, several multicast routing protocols (MRP) have been proposed in MANETs. Depending on whether security is built‐in or added, MRP can be classified into two types: secure and security‐enhanced routing protocols, respectively. This paper presents a survey on secure and security‐enhanced MRP along with their security techniques and the types of attacks they can confront. A detailed comparison for the capability of the various routing protocols against some known attacks is also presented and analyzed. Copyright © 2013 John Wiley & Sons, Ltd.     

Oxidation Properties of a Beta-Stabilized TiAl Alloy Modified by Rare Earth Elements

This paper explores the effects of adding rare earth elements (lanthanum or erbium) on the oxidation properties of Ti–43.5Al–4Nb–1Mo–0.1B (TNM) alloy. Isothermal oxidation tests were performed under air atmosphere at 900 and 1000 °C. Mass gain was measured in several steps during the oxidation test, and the oxidized specimens were characterized by XRD and FE-SEM. The results showed that while adding 0.1 at.% rare earth elements (REEs) reduced oxidation rate of the TNM alloy, 0.2 at.% REEs addition increased the mass gain of the alloys. The oxidation curves were fitted by a power-law equation; the results showed that the oxidation kinetic curves of all alloys obeyed parabolic growth kinetics (n = 2). Meanwhile, the activation energy of oxidation was in the range of 40–50 kCal/mol, thereby suggesting that the scale growth was controlled by mass transport in the TiO₂ layer. Also, the results of the scale characterization showed that addition of REEs at low level (e.g., 0.1 at.%) could reduce diffusion rate in the scale. However, addition of the higher amounts of La or Er (e.g., 0.2 at.%) due to the lower valency (+ 3) of these elements, as compared with Ti (+ 4), could lead to the increased anion diffusion, the formation of hillocks in the scale and a rise of the oxidation rate.     

Preparation of PET/clay nanocomposites via in situ polymerization in the presence of monomer‐activated organoclay

Various polyethylene terephthalate (PET)/clay nanocomposites containing a commercial organoclay (organophilic montmorillonite nanoclay [OMMT]) and a monomer‐activated OMMT (remodified OMMT) were prepared via in situ interlayer polycondensation of dimethyl terephthalate and ethylene glycol. In order to remodify the commercial OMMT nanoparticles, a diacid chloride monomer was applied. The prepared nanocomposites were characterized by diverse methods, including X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and intrinsic viscosity measurements. The results of the study revealed that the PET/(remodified OMMT) nanocomposites possess a better state of clay dispersion as well as significantly better thermal properties as compared with the PET/OMMT nanocomposites. Moreover, the PET/(remodified OMMT) nanocomposites showed higher crystallization temperature, degree of crystallinity, maximum degradation temperature, and lower half‐time of crystallization than that of the PET/OMMT nanocomposites. It was found that the remodification process for OMMT led to less of a foaming problem during in situ polymerization. J. VINYL ADDIT. TECHNOL., 21:70–78, 2015. © 2014 Society of Plastics Engineers     

Using affective human-machine interface to increase the operation performance in virtual construction crane training system: A novel approach

In the construction industry, some progress have been achieved by researchers to design and implement environments for task training using VR technology and its derivatives such as Augmented and Mixed Reality. Although, these developments have been well recognized at the application level, however crucial to the virtual training system is the effective and reliable measurement of training performance of the particular skill and handling the experiment for long-run. It is known that motor skills cannot be measured directly, but only inferred by observing behaviour or performance measures. The typical way of measuring performance is through measuring task completion time and accuracy, but can be supported by indirect measurement of some other factors. In this paper, a virtual crane training system has been developed which can be controlled using control commands extracted from facial gestures and is capable to lift up loads/materials in the virtual construction sites. Then, we integrate affective computing concept into the conventional VR training platform for measuring the cognitive load and level of satisfaction during performance using human's forehead bioelectric-signals. By employing the affective measures and our novel control scheme, the designed interface could be adapted to user's affective status during the performance in real-time. This adaptable user interface approach helps the trainee to cope with the training for long-run performance, leads to gaining more expertise and provides more effective transfer of learning to other operation environments. The detailed methodology of the affective control is presented in the paper. The results and future applications of the proposed method for disabled users, especially from neck down are discussed.     

Short- and long-term rheological and chemical characteristics of nanomodified asphalt binder

Due to the special characteristics of nanoparticles, pavement engineers have used nanoparticles as an additive in asphalt pavement to improve pavement performance. This study focuses on characterizing modified asphalt performance using nanoclay particles compared to the unmodified asphalt binder. For this evaluation, 3% of nanoclay particles were added to a neat binder to prepare the nanomodified binder. Then, the modified and unmodified binders underwent a short- and long-term aging process using the Rolling Thin Film Oven (RTFO) and two cycles of Pressure Aging Vessel (PAV). Finally, the Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR), and Fourier-Transform Infrared Spectroscopy - Attenuated Total Reflection (FTIR-ATR) tests were carried out in each aging step to assess and monitor the rutting, fatigue, low-temperature performance, durability, and chemical changes of binders during the aging process. The results of this study proved the enhanced properties and performances of the nanomodified binder compared to the unmodified binder. These results can pave the path with the use of nanomodified binders in the recycling of aged pavement and construction of roads that experience poor weather conditions and high traffic loads.     

An efficient technique for dairy wastewater treatment

The aim of this study was to consider the efficiency of the electro‐Fenton process for organic compound reduction in an industrial dairy effluent. Experiments were conducted to evaluate the effect of several parameters, such as reaction time, pH, H₂O₂/Fe²⁺ molar ratio and volume fraction of H₂O₂ to dairy wastewater (mL/L), on the process performance. The Taguchi technique was applied to investigate the optimum operating conditions. The optimum chemical oxygen demand removal (93.24%) was experimentally obtained at a pH value of 7.58, reaction time of 87.13, current density of 58.5, H₂O₂/Fe²⁺ molar ratio of 3.62 and volume fraction of H₂O₂ to dairy wastewater of 1.39 mL/L.     

The Role of Centrosome Distal Appendage Proteins (DAPs) in Nephronophthisis and Ciliogenesis

The primary cilium is found in most mammalian cells and plays a functional role in tissue homeostasis and organ development by modulating key signaling pathways. Ciliopathies are a group of genetically heterogeneous disorders resulting from defects in cilia development and function. Patients with ciliopathic disorders exhibit a range of phenotypes that include nephronophthisis (NPHP), a progressive tubulointerstitial kidney disease that commonly results in end-stage renal disease (ESRD). In recent years, distal appendages (DAPs), which radially project from the distal end of the mother centriole, have been shown to play a vital role in primary ciliary vesicle docking and the initiation of ciliogenesis. Mutations in the genes encoding these proteins can result in either a complete loss of the primary cilium, abnormal ciliary formation, or defective ciliary signaling. DAPs deficiency in humans or mice commonly results in NPHP. In this review, we outline recent advances in our understanding of the molecular functions of DAPs and how they participate in nephronophthisis development.     

Cylindrical electron–hole bilayer TFET with a single surrounding gate and induced quantum confinement

Journal of Computational Electronics - In this paper, for the first time, an electron–hole bilayer TFET based on a cylindrical architecture with a single surrounding gate is proposed. The...