Elastoplastic stress analysis of functionally graded disc under internal pressure– complas XII

The study deals with elastoplastic stress analysis of a hollow disk made of functionally graded materials (FGMs) subjected to an internal pressure. The material properties of disc are assumed to vary radially according to power law function, but Poisson’s ratio is taken constant. Small deformations and a state of plane stress are presumed, and the analysis of disk is based on Von-Mises yield criterion. The materials are assumed to be linear strain hardening, isotropic and not be affected by temperature. Variation of stresses and displacements according to gradient parameters are investigated by using analytical and finite element method. The results show that gradient parameters have an important role in determining the elastoplastic stress of functionally graded disc

Investigation of experimental research on the low velocity impact damage behavior of ncf composite plates – COMPLAS XII

In this study an experimental investigation is performed on the impact response of non-crimp fabric composite plates at room temperature. Chopped strand mat combi is used as reinforcing material and two kinds of matrix; epoxy and polyester, are also used as resin material in the composite plates. All specimens used in experiments are manufactured by vacuum assisted resin infusion method at Atard Defence and Aerospace Advanced Technology Application Research and Development Inc. An instrumented drop weight impact testing machine Instron-Dynatup 9250 HV is used for impact testing. Impact tests are performed under various impact energies ranging from initiation of damage to final perforation. Damage processes of the samples are analyzed from cross-examining load– deflection curves, energy profiling method and damaged specimens

Are open educational resources the future of e-learning?

Increased interest in more open approaches to learning, in particular Open Educational Resources is reflected in the programmes of international organisations, national initiatives and the actions of individual institutions. However, while some see OER as an indicator of the future of learning, others are much more sceptical and doubt their long-term success. This paper considers the vision of OER as part of future learning solutions in the society driven by technology and knowledge. Supported by an examination of specific national contexts and linked to research from relevant initiatives arguments in favour of using OER are outlined. These include their value in both developing and developed countries, and flexible ways of use in structured courses and in informal, learner-driven environments. This is balanced by highlighting concerns that relate mainly to current issues of certification, quality and intellectual property rights, but also potential problems such as the lack of instructor-learner interaction and the dominance of OER initiatives from English-speaking universities. The paper concludes that OER have an immense potential as long as the elements that contribute to their success are identified and harnessed, and barriers effectively dealt with

Anatomical characteristics of the lingual foramen in ancient skulls: a cone beam computed tomography study in an Anatolian population

Background: The purpose of this study is to evaluate the anatomical features of lingual foramina and their bony canals in Anatolian ancient mandibles (9–10th century) by using cone beam computed tomography (CBCT). Materials and methods: Fifty-eight ancient dry mandibles were scanned with CBCT. Lingual foramina were grouped into midline, paramedian, posterior foramina and combination of these groups. Midline group was also classified according to internal surface of the mandible (gonial tubercles [GTs]). The incidence, vertical distance and diameter of lingual foramina were measured according to age groups and gender. Results: The incidence of the lingual foramen was 96.6%. Midline of the symphysis had the highest incidence (34.4%) of foramina (p < 0.05), followed by both midline and paramedian type (32.8%; p < 0.05). Classification in terms of GT represented class 3 as the most encountered group (28.6%). Number of foramina observed in the mandibles ranged from 0 to 6 with the incidence of 3.4% and 32.8%, respectively. The male and < 35 years groups presented larger measurement values in midline region (p < 0.05). Conclusions: Mandibular lingual foramina and bony canals are frequently present in ancient mandibles. When compared with modern subjects, similar findings are observed according to published literatures. CBCT is also proved to be an effective imaging modality in the detection of lingual foramina and canals in anthropological studies

Delayed diagnosis of oral squamous cell carcinoma: a case series

<p>Abstract</p> <p>Introduction</p> <p>In malign neoplasms, oral cancer is one of the important causes of mortality and morbidity. Squamous cell carcinoma is the most common form of oral cancers in adults and is related to risk factors such as smoking and alcohol consumption.</p> <p>Case presentation</p> <p>In this article, we present three case reports of oral squamous cell carcinomas with delayed diagnosis. The first patient was a 52-year-old Turkish man, the second patient was a 61-year-old Turkish man and the third patient was a 60-year-old Turkish woman. All were referred to the Ankara University Faculty of Dentistry with pain, swelling and various complaints in their jaws.</p> <p>Conclusion</p> <p>Early diagnosis is of vital importance for the prognosis of the patients with oral squamous cell carcinomas. For this reason, dentists play a crucial role in the early detection and prevention of oral cancers.</p

Single-molecule correlated chemical probing of RNA

RNA molecules function as the central conduit of information transfer in biology. To do this, they encode information both in their sequences and in their higher-order structures. Understanding the higher-order structure of RNA remains challenging. In this work we devise a simple, experimentally concise, and accurate approach for examining higher-order RNA structure by converting widely used massively parallel sequencing into an easily implemented single-molecule experiment for detecting through-space interactions and multiple conformations. We then use this experiment to analyze higher-order RNA structure, detect biologically important hidden states, and refine accurate three-dimensional structure models

Low Power and High Speed Multi Threshold Voltage Interface Circuits

Employing multiple supply voltages (multi-V-DD) is an effective technique for reducing the power consumption without sacrificing speed in an integrated circuit (IC). In order to transfer signals among the circuits operating at different voltage levels specialized voltage interface circuits are required. Two novel multi-threshold voltage (multi-V-th) level converters are proposed in this paper. The new multi-V-th, level converters are compared with the previously published circuits for operation at different supply voltages. When the circuits are individually optimized for minimum power consumption, the proposed level converters offer significant power savings of up to 70\% as compared to the previously published circuits. Alternatively, when the circuits are individually optimized for minimum propagation delay, the speed is enhanced by up to 78\% with the proposed voltage interface circuits in a 0.18-mu m TSMC CMOS technology

CLOCK DISTRIBUTION NETWORKS WITH GRADUAL SIGNAL TRANSITION TIME RELAXATION FOR REDUCED POWER CONSUMPTION

Clock distribution network consumes a significant portion of the total chip power since the clock signal has the highest activity factor and drives the largest capacitive load in a synchronous integrated circuit. A new methodology is proposed in this paper for buffer insertion and sizing in an H-tree clock distribution network. The objective of the algorithm is to minimize the total power consumption while satisfying the maximum acceptable clock transition time constraints at the leaves of the clock distribution network for maintaining high performance. The new methodology employs nonuniform buffer insertion and progressive relaxation of the transition time requirements from the leaves to the root of the clock distribution network. The proposed algorithm provides up to 30\% savings in the total power consumption without sacrificing clock skew as compared to a standard algorithm with uniform buffer insertion aimed at maintaining uniform transition time constraints at all the nodes of a clock tree in a 180 nm CMOS technology

Multi-Threshold Voltage FinFET Sequential Circuits

New multi threshold voltage (multi-V(th)) brute-force FinFET sequential circuits with independent-gate bias, work-function engineering, and gate-drain/source overlap engineering techniques are presented in this paper. The total active mode power consumption, the clock power, and the average leakage power of the multi-V(th) sequential circuits are reduced by up to 55%, 29%, and 53%, respectively, while maintaining similar speed and data stability as compared to the circuits in a single threshold voltage (single-V(th)) tied-32 nm-gate FinFET technology. Furthermore, the area is reduced by up to 21% with the new sequential circuits as compared to the circuits with single-V(th) tied-gate FinFETs

Dual Supply Voltages and Dual Clock Frequencies for Lower Clock Power and Suppressed Temperature-Gradient-Induced Clock Skew

Two new clocking methodologies based on supply voltage and frequency scaling are proposed in this paper for lowering the power consumption and the temperature-fluctuation-induced skew without degrading the clock frequency. The clock signal is distributed globally at a scaled supply voltage with a single clock frequency with the first clocking methodology. Alternatively, dual supply voltages and dual signal frequencies are employed with the second methodology that provides enhanced power savings. The optimum supply voltage that minimizes clock skew is 44\% lower than the nominal supply voltage in a 0.18 mu m TSMC CMOS technology. Novel multi-threshold voltage level converters and frequency multipliers are employed at the leaves of the clock trees in order to maintain the synchronous system performance. The temperature-fluctuation-induced skew and the power consumption are reduced by up to 80\% and 76\%, respectively, with the proposed dual supply voltage and dual frequency clock distribution networks as compared to a standard clock tree operating at the nominal supply voltage with a single clock frequency