bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy Consumption Prediction System of Mechanical Processes Based on Empirical Models and Computer-Aided Manufacturing
Authors: He Keyan , Tang Renzhong , Zhang Zhongwei , Sun Wenjun
Published: June 2016

Energy consumption prediction at the process planning stage is the basis of mechanical process optimization aiming at saving energy and reducing carbon emission. The accuracy and efficiency of the prediction method will be the most concerning issues. This paper presents an energy consumption prediction system of mechanical processes based on empirical models and computer-aided manufacturing (CAM). The system was developed based on analysis of energy-related data and data acquiring methods. The energy consumption sources of mechanical processes are divided into two parts: energy of auxiliary machine movements and intrinsic process movements. Considering data sources, there are two kinds of data acquiring methods: acquiring data from database or from CAM files. Process energy state is introduced to support calculation of energy consumption and presentation of calculation results. Example of the system was developed based on Microsoft SQL Server 2008 and ugs nx 7.0, and several examples of energy prediction of mechanical processes were also presented. The results demonstrate that the proposed system developing method is effective in predicting energy consumption of mechanical processes with high accuracy and high efficiency.
Local Microstructure and Hardness Variation After Pulsed Laser Micromelting on S7 Tool Steel
Authors: Morrow Justin D. , Pfefferkorn Frank E.
Published: June 2016

Laser surface melting is being increasingly used as a method of surface polishing steels and other alloys, but understanding the effect of this process on the microstructure and properties is still incomplete. This work experimentally explores several basic questions about how the surface microstructure and properties of S7 tool steel change during a pulsed laser micromelting (PLμM) process. Evaluations of the microstructure and hardness suggest that diffusion-controlled processes such as melt homogenization and surface back-tempering are relevant during rapid microscale laser melting and that the laser parameters and process planning contribute to determining the final surface hardness. The results also suggest that some influence can be exerted over the final hardness obtained from laser surface melting by changing the processing parameters.
Stress Field Analysis in Orthogonal Cutting Process Using Digital Image Correlation Technique
Authors: Zhang Dong , Zhang Xiao-Ming , Xu Wen-Jie , Ding Han
Published: June 2016

Cutting stress field in machining process plays a significant role in the understanding of cutting mechanics and prediction of surface integrity, tool wear, and failure. It is in great need to get accurate and reliable cutting stresses in the chip formation zone. In this paper, a new methodology to obtain the cutting stress field is proposed. The deformation field containing elastic as well as plastic parts can be obtained via digital image correlation (DIC) technique. The orthogonal cutting stress field can be obtained with the experimental determined deformation field and material constitutive model as inputs. However, the challenge is to handle the inaccuracy of infinitesimal elastic deformation involved in the total deformation due to the inaccuracy of the obtained images. We develop a method to modify the hydrostatic pressure field based on mechanical equilibrium equations to compensate the inaccuracy of elastic deformation part. Besides, Eulerian logarithmic strain based on a least square plane fit on a subset of displacement data is adopted to reduce the image noise. The stress distribution along the shear plane and tool–chip interface can be extracted and integrated to calculate cutting forces. A feasibility study is performed by comparing the cutting forces predicted based on this new method against the experimental measurements. The comparison of cutting parameters obtained through DIC technique with finite element method (FEM) predictions is also made.
Piezo-Actuated Modulation-Assisted Drilling System With Integrated Force Sensing
Authors: Guo Yang , Lee Seong Eyl , Mann James B.
Published: June 2016

A new electromechanical modulation system designed with piezoelectric stacks for both linear actuation and force sensing functions is described. The system can be adapted for modulation-assisted machining (MAM) drilling processes where a low-frequency (<1000 Hz) sinusoidal oscillation is superimposed directly onto the drilling process, such that the feedrate is modulated. A series of drilling experiments were conducted in Ti6Al4V, 17-4 steel, and Al6061 with the system installed on a CNC machine. The drill displacement, thrust force, and chip morphology were characterized across a range of conventional and MAM drilling conditions. The mechanical response (stiffness) of the system agrees with the design specifications. The system offers new capabilities to control the modulation frequency and amplitude in MAM drilling, while simultaneously measuring the drilling thrust force in real time. The force sensing function enables detection of the intermittent separations between the drill tip and the workpiece surface (occurrence of discrete cutting), providing a method to prescribe and control the modulation conditions necessary for effective MAM drilling. Opportunities for force feedback control and process monitoring in MAM drilling processes are discussed. While the system described emphasizes MAM drilling, the capabilities can be extended to other machining processes.
Hoar Frost Accretion on Organic Coatings Under Offshore Conditions
Authors: Momber A. W. , Irmer M. , Glück N.
Published: June 2016

Nine organic corrosion protection coating systems are investigated according to their hoar frost accretion performance under simulated offshore conditions. A special test scenario is developed for the generation and measurement of defined hoar frost layers. Hoar frost layer thickness is estimated on newly applied coatings and on artificially aged coatings. The aging procedure refers to offshore conditions, which mainly cover low temperatures, dry–wet cycles, salt spray, and ultraviolet (UV) radiation. In average, the accreted thickness either did not change significantly or increased. Spearman's rank correlations were estimated for all surface parameters. If all measurements (new and aged) for an individual surface parameter were considered, only weak correlations were found between hoar frost thickness, static contact angle, specific surface energy, and surface roughness. The importance of UV radiation on the appearance of hoar frost is highlighted.
An Expert-Based Model for Reliability Analysis of Arctic Oil and Gas Processing Facilities
Authors: Naseri Masoud , Barabady Javad
Published: June 2016

Oil and gas companies are expanding their operations in the remote Arctic offshore with harsh weather conditions such as the Barents Sea. One of the major challenges in reliability assessment of production plants operating in such areas is lack of life data accounting for the adverse effects of harsh operating conditions. The aim of this study is to develop an expert-based model to assess the reliability of oil and gas exploration and production plants operating in Arctic regions. Expert opinions are used to modify the life data available in normal-climate locations, which are considered as the base area, to account for the effects of operating conditions. The proposed model is illustrated by assessing the reliability of an oil processing train in the Western Barents Sea. Additionally, based on a criticality analysis, some design modifications are suggested to improve the reliability of the processing train.
Evaluation of Leakage Through Graphite-Based Compression Packing Rings
Authors: Kazeminia Mehdi , Bouzid Abdel-Hakim
Published: June 2016

The prediction of leakage is one of the most challenging tasks when designing bolted flanged connections and industrial valves. Failure of these pressure vessel components can cause shutdowns but also accidents, loss of revenue, and environmental damages. With the strict regulations on fugitive emissions and environmental protection laws new tightness-based standards and design methods are being adopted to improve the sealing performance of bolted joints and valves. In addition, there is a practical interest in using a reliable correlation that could predict leak rates of one fluid on the basis of tests carried out with another on compressed packings. The paper presents an innovative approach to accurately predict and correlate leak rates in porous braided packing rings. The approach is based on Darcy–Klinkenberg to which a modified effective diffusion term is added to the equation. Experimentally measured gas flow rates were performed on a set of graphite-based compression packing rings with a large range of leak rates under isothermal steady conditions. Leakage from three different gases namely helium, nitrogen, and argon were used to validate the developed correlation. In the presence of the statistical properties of porous packings, the leak rates for different gases can be predicted with reasonable accuracy.
Experimental Investigations on Three-Dimensional Blading Optimization for Low-Speed Model Testing
Authors: Zhang Chenkai , Hu Jun , Wang Zhiqiang , Li Jun
Published: June 2016

Low-speed model testing (LSMT) plays a key role in advanced multistage high-pressure compressor (HPC) design recently, due to this, employing low-speed large-scale compressor to conduct 3D blading design and detailed flow mechanism investigation is convenient and cost-saving. This paper is one portion of a whole LSMT project for the seventh stage of an advanced commercial HPC, and experimental investigations of 3D blading optimizations for LSMT were presented in this paper, consisting of overall performances for the compressor and stage 3 and detailed flowfield measurements including area traverse for rotor 3 inlet, stator 3 inlet and outlet, area traverse inside stator 3 passage, and static pressure on stator 3 blade surface. Compared with the datum compressor, revised rotor 3 is J-type and hub restaggered, and the improved stator 3 possesses characteristics of controlled camber angle, reduced leading blade angle, forward movement of maximum thickness position, and larger bowed-shape. Experimental results show that efficiency is improved by 1%, and total pressure rise for the compressor and the third stage is raised by 1.4% and 10%, respectively, while the stalling mass flow rate is maintained. The effectiveness of improved design methods is confirmed, and it is a guide for further blading design and optimization, furthermore, detailed flowfield measurements reveal the basic flow mechanism of all the improvement methods. Moreover, the results indicate that utilization of cfd code in the optimization procedure is promising, and the reliability and feasibility of cfd code are verified with the detailed experimental results.
Composite Cylinders for Deep Sea Applications: An Overview
Authors: Davies Peter , Choqueuse Dominique , Bigourdan Benoît , Chauchot Pierre
Published: June 2016

In order to develop the knowledge base necessary to design deep sea pressure vessels, it is essential to understand the full chain from design and manufacturing through nondestructive testing (NDT) and characterization to long-term behavior under hydrostatic pressure. This paper describes results from European and national research programs focusing on the use of composites for underwater applications over the last 20 years. Initial tests on small glass/epoxy cylinders were followed by large demonstration projects on carbon/epoxy cylinders with implosion pressures of up to 600 bar, corresponding to 6000 m depth. Numerical modeling has enabled end closures design to be optimized for test performance. Thin and thick wall cylinders have been tested under quasi-static, and long-term loading. Both thermosetting and thermoplastic matrix composites have been tested to failure, and the influence of defects and impact damage on implosion pressure has been studied. These deep sea exploitation and exploration studies were performed for oceanographic, military, and offshore applications, and extensive data are available. The aim of this paper is to indicate existing results, particularly from European projects, in order to avoid costly repetition.
Stabilization of a Rigid Body Payload With Multiple Cooperative Quadrotors
Authors: Goodarzi Farhad A. , Lee Taeyoung
Published: June 2016

This paper presents the full dynamics and control of arbitrary number of quadrotor unmanned aerial vehicles (UAVs) transporting a rigid body. The rigid body is connected to the quadrotors via flexible cables where each flexible cable is modeled as a system of arbitrary number of serially connected links. It is shown that a coordinate-free form of equations of motion can be derived for the complete model without any simplicity assumptions that commonly appear in other literature, according to Lagrangian mechanics on a manifold. A geometric nonlinear controller is presented to transport the rigid body to a fixed desired position while aligning all of the links along the vertical direction. A rigorous mathematical stability proof is given and the desirable features of the proposed controller are illustrated by numerical examples and experimental results.
Stability of Nonlinear Stochastic Distributed Parameter Systems and Its Applications
Authors: Do K. D.
Published: June 2016

This paper derives several well-posedness (existence and uniqueness) and stability results for nonlinear stochastic distributed parameter systems (SDPSs) governed by nonlinear partial differential equations (PDEs) subject to both state-dependent and additive stochastic disturbances. These systems do not need to satisfy global Lipschitz and linear growth conditions. First, the nonlinear SDPSs are transformed to stochastic evolution systems (SESs), which are governed by stochastic ordinary differential equations (SODEs) in appropriate Hilbert spaces, using functional analysis. Second, Lyapunov sufficient conditions are derived to ensure well-posedness and almost sure (a.s.) asymptotic and practical stability of strong solutions. Third, the above results are applied to study well-posedness and stability of the solutions of two exemplary SDPSs.
Multirate Output Feedback Based Stochastic Sliding Mode Control
Authors: Mehta A. J. , Bandyopadhyay B.
Published: June 2016

In this paper, a multirate output feedback (MROF) based discrete-time sliding mode control for the stochastic system with slowly varying bounded uncertainty is proposed. The states are estimated by the multirate Kalman filter and are used for designing the stochastic sliding mode controller which guarantee the stability under the bounded uncertainty and the uncertain noise covariance. The proposed algorithm has advantage of computational and implementation simplicity as it requires only the past output and input information. The stochastic sliding band (SSB) is also calculated which is found to be wider as compared to the state feedback case. Finally, the design procedure for stochastic sliding mode controller is demonstrated with an illustrative example.
Optimum Design of a Passive Suspension System of a Semisubmersible for Pitching Reduction
Authors: Zhu Hongzhong , Hu Changhong , Liu Yingyi
Published: June 2016

With the development of ocean energy exploration, reliable semisubmersible platforms with very small motion are expected to develop. Especially, in a floating offshore wind turbine (FOWT) system, the maximum pitching amplitude is required to be less than a few degrees. To reduce wave-induced pitch motion, a new type semisubmersible with suspensions and a design method of the suspension coefficients are presented. In practical case, an add-on wave energy dissipation device mounted on a floating platform, such as the combined wave-wind energy converter system, could be regarded as the suspension system. In this study, first, the conceptual semisubmersible is described. Then, the hydrodynamic loads to the semisubmersible are linearized so that the whole system is expressed by a state-space model. The suspension design problem is transformed into solving a constrained H∞ optimization problem, which after all is the optimal controller design of a feedback system. Finally, numerical examples are performed to verify the effectiveness of the design. The results illustrate that the pitch motion of the semisubmersible can be remarkably reduced by the designed suspensions.
Characterization of the Dominant Structural Vibration of Hearing Aid Receivers
Authors: Varanda B. R. , Miles R. N. , Warren D.
Published: June 2016

Results are presented of an analysis and characterization of the mechanical vibration of hearing aid receivers, a key electroacoustic component of hearing aids. The function of a receiver in a hearing aid is to provide an amplified sound signal into the ear canal. Unfortunately, as the receiver produces sound, it also undergoes vibration which can be transmitted through the hearing aid package to the microphones, resulting in undesirable feedback oscillations. To better understand and control this important source of feedback in hearing aids, a rigid body model is proposed to describe the essential dynamic features of the system. The receiver is represented by two hinged rigid bodies, under an equal and opposite dynamic moment load, and connected to each other by a torsional spring and damper. A method is presented to estimate the parameters for the proposed model using experimental data. The data were collected from translational velocity measurements using a scanning laser vibrometer of a Knowles ED-series receiver supported on a complaint foundation. Excellent agreement is shown between results obtained using the analytical model and the measured translation and rotation of an independent receiver. It is concluded that a dynamic model of the receiver must account for both rotation and translation of the structure in order to properly describe its motion due to an input current.
Effect of pulse sequence parameter selection on signal strength in positive‐contrast MRI markers for MRI‐based prostate postimplant assessment
Authors: Lim Tze Yee , Kudchadker Rajat J. , Wang Jihong , Stafford R. Jason , MacLellan Christopher , Rao Arvind , Ibbott Geoffrey S. , Frank Steven J.
Published: June 2016

Purpose:

For postimplant dosimetric assessment, computed tomography (CT) is commonly used to identify prostate brachytherapy seeds, at the expense of accurate anatomical contouring. Magnetic resonance imaging (MRI) is superior to CT for anatomical delineation, but identification of the negative‐contrast seeds is challenging. Positive‐contrast MRI markers were proposed to replace spacers to assist seed localization on MRI images. Visualization of these markers under varying scan parameters was investigated.

Methods:

To simulate a clinical scenario, a prostate phantom was implanted with 66 markers and 86 seeds, and imaged on a 3.0T MRI scanner using a 3D fast radiofrequency‐spoiled gradient recalled echo acquisition with various combinations of scan parameters. Scan parameters, including flip angle, number of excitations, bandwidth, field‐of‐view, slice thickness, and encoding steps were systematically varied to study their effects on signal, noise, scan time, image resolution, and artifacts.

Results:

The effects of pulse sequence parameter selection on the marker signal strength and image noise were characterized. The authors also examined the tradeoff between signal‐to‐noise ratio, scan time, and image artifacts, such as the wraparound artifact, susceptibility artifact, chemical shift artifact, and partial volume averaging artifact. Given reasonable scan time and managable artifacts, the authors recommended scan parameter combinations that can provide robust visualization of the MRI markers.

Conclusions:

The recommended MRI pulse sequence protocol allows for consistent visualization of the markers to assist seed localization, potentially enabling MRI‐only prostate postimplant dosimetry.
UAV photogrammetry for mapping vegetation in the low-Arctic
Authors: Fraser Robert H. , Olthof Ian , Lantz Trevor C. , Schmitt Carla
Published: June 2016

Plot-scale field measurements are necessary to monitor changes to tundra vegetation, which has a small stature and high spatial heterogeneity, while satellite remote sensing can be used to track coarser changes over larger regions. In this study, we explored the potential of unmanned aerial vehicle (UAV) photographic surveys to map low-Arctic vegetation at an intermediate scale. A multicopter was used to capture highly overlapping, subcentimetre photographs over a 2 ha site near Tuktoyaktuk, Northwest Territories. Images were processed into ultradense 3D point clouds and 1 cm resolution orthomosaics and vegetation height models using Structure-from-Motion (SfM) methods. Shrub vegetation heights measured on the ground were accurately represented using SfM point cloud data (r2 = 0.96, SE = 8 cm, n = 31) and a combination of spectral and height predictor variables yielded an 11-class classification with 82% overall accuracy. Differencing repeat UAV surveys before and after manually trimming shrub patches showed that vegetation height decreases in trimmed areas (− 6.5 cm, SD = 21 cm). Based on these findings, we conclude that UAV photogrammetry provides a promising, cost-efficient method for high-resolution mapping and monitoring of tundra vegetation that can be used to bridge the gap between plot and satellite remote sensing measurements.
Sublethal consequences of urban life for wild vertebrates
Authors: Birnie-Gauvin Kim , Peiman Kathryn S. , Gallagher Austin J. , de Bruijn Robert , Cooke Steven J.
Published: June 2016

Urbanization is modifying previously pristine natural habitats and creating “new” ecosystems for wildlife. As a result, some animals now use habitat fragments or have colonized urban areas. Such animals are exposed to novel stimuli that they have not been exposed to in their evolutionary history. Some species have adapted to the challenges they face — a phenomenon known as synurbanization — while others have not. Here we present a review of the sublethal consequences of life in the city for wild vertebrates, and demonstrate that urban animals face an almost completely different set of physiological and behavioural challenges compared to their rural counterparts. We focus on the negative fitness-related impacts of urbanization, but also identify instances where there are benefits to wildlife. The effects of urbanization appear to be both species- and context-dependent, suggesting that although the field of urban ecology is far from nascent, we are still just beginning to understand how the intricacies of biodiversity on our planet are affected by our presence.
High scale mixing relations as a natural explanation for large neutrino mixing
Authors: Abbas Gauhar , Abyaneh Mehran Zahiri , Biswas Aritra , Gupta Saurabh , Patra Monalisa , Rajasekaran G. , Srivastava Rahul
Published: June 2016

The origin of small mixing among the quarks and a large mixing among the neutrinos has been an open question in particle physics. In order to answer this question, we postulate general relations among the quarks and the leptonic mixing angles at a high scale, which could be the scale of Grand Unified Theories. The central idea of these relations is that the quark and the leptonic mixing angles can be unified at some high scale either due to some quark–lepton symmetry or some other underlying mechanism and as a consequence, the mixing angles of the leptonic sector are proportional to that of the quark sector. We investigate the phenomenology of the possible relations where the leptonic mixing angles are proportional to the quark mixing angles at the unification scale by taking into account the latest experimental constraints from the neutrino sector. These relations are able to explain the pattern of leptonic mixing at the low scale and thereby hint that these relations could be possible signatures of a quark–lepton symmetry or some other underlying quark–lepton mixing unification mechanism at some high scale linked to Grand Unified Theories.
Subdominant left–right scalar dark matter as origin of the 750 GeV di-photon excess at LHC
Authors: Borah Debasish , Patra Sudhanwa , Sahoo Shibananda
Published: June 2016

We study the possibility of explaining the recently reported 750 GeV di-photon excess at LHC within the framework of a left–right symmetric model. The 750 GeV neutral scalar in the model is dominantly an admixture of neutral components of scalar bidoublets with a tiny fraction of neutral scalar triplet. Incorporating [Formula: see text] septuplet scalar pairs into the model, we enhance the partial decay width of the 750 GeV neutral scalar into di-photons through charged septuplet components in loop while keeping the neutral septuplet components as subdominant dark matter candidates. The model also predicts the decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or ruled out by future LHC data. The requirement of producing the correct di-photon signal automatically keeps the septuplet dark matter abundance subdominant in agreement with bounds from direct and indirect detection experiments. We then briefly discuss different possibilities to account for the remaining dark matter component of the Universe in terms of other particle candidates whose stability arises either due to remnant discrete symmetry after spontaneous breaking of [Formula: see text] or due to high [Formula: see text]-dimension forbidding their decay into lighter particles.
Production of massless bottom jets in pp̄ and pp collisions at next-to-leading order of QCD
Authors: Bierenbaum Isabella , Kramer Gustav
Published: June 2016

We present predictions for the inclusive production of bottom jets in proton–antiproton collisions at 1.96 TeV and proton–proton collisions at 7 TeV. The bottom quark is considered massless. In this scheme, we find that at small transverse momentum [Formula: see text] the ratio of the next-to-leading order to the leading-order cross-section ([Formula: see text] factor) is smaller than one. It increases with increasing [Formula: see text] and approaches one at larger [Formula: see text] at a value depending essentially on the choice of the renormalization scale. Adding nonperturbative corrections obtained from PYTHIA Monte Carlo calculations leads to reasonable agreement with experimental [Formula: see text]-jet cross-sections obtained by the CDF and the CMS collaborations.
Long-wavelength lattice vibrations of Ag3In5Se9 and Ag3In5Te9 single crystals — An inversion of LO- and TO-mode frequencies
Authors: Gasanly Nizami Mamed
Published: June 2016

Infrared (IR) reflectivities are registered in the frequency range of 50–2000 cm[Formula: see text] for Ag3In5Se9 and Ag3In5Te9 single crystals grown by Bridgman method. Three infrared-active modes are detected in spectra. The optical parameters, real and imaginary parts of the dielectric function, the function of energy losses, refractive index, absorption index and absorption coefficient were calculated from reflectivity experiments. The frequencies of transverse and longitudinal optical modes (TO and LO modes) and oscillator strength were also determined. The bands detected in infrared spectra were tentatively attributed to various vibration types (valence and valence-deformation). The inversion of LO- and TO-mode frequencies of the sandwiched pair was observed for studied crystals.
Hybrid models in loop quantum cosmology
Authors: Elizaga Navascués Beatriz , Martín-Benito Mercedes , Mena Marugán Guillermo A.
Published: June 2016

In the framework of Loop Quantum Cosmology (LQC), inhomogeneous models are usually quantized by means of a hybrid approach that combines loop quantization techniques with standard quantum field theory methods. This approach is based on a splitting of the phase space in a homogeneous sector, formed by global, zero-modes and an inhomogeneous sector, formed by the remaining, infinite number of modes, that describe the local degrees of freedom. Then, the hybrid quantization is attained by adopting a loop representation for the homogeneous gravitational sector, while a Fock representation is used for the inhomogeneities. The zero-mode of the Hamiltonian constraint operator couples the homogeneous and inhomogeneous sectors. The hybrid approach, therefore, is expected to provide a suitable quantum theory in regimes where the main quantum effects of the geometry are those affecting the zero-modes, while the inhomogeneities, still being quantum, can be treated in a more conventional way. This hybrid strategy was first proposed for the simplest cosmological midisuperspaces: the Gowdy models, and it has been later applied to the case of cosmological perturbations. This paper reviews the construction and main applications of hybrid LQC.
INNOVATIVE BORN GLOBALS: INVESTIGATING THE INFLUENCE OF THEIR BUSINESS MODELS ON INTERNATIONAL PERFORMANCE
Authors: KRAUS SASCHA , BREM ALEXANDER , SCHUESSLER MIRIAM , SCHUESSLER FELIX , NIEMAND THOMAS
Published: June 2016

Internationalization is a hot topic in innovation management, whereby the phenomenon of “Born Globals” is still limited to research in the domains of Entrepreneurship and International Management. As business model design plays a key role for Born Globals, we link these two concepts. For this, we propose hypotheses about the influence of efficiency-centered and novelty-centered business model design on international firm performance. To test these hypotheses, we performed a quantitative survey with 252 founders of international companies in Germany, Switzerland and Liechtenstein. Additionally, we gained further insights through a case study analysis of 11 Born Globals. The results show that business model design matters to international firm performance and the business model design of Born Globals tends to be more efficiency-centered. Based on a multiple case study, we analyzed business models in a more sophisticated way and derived propositions that yielded in an archetype of a Born Global’s business model.
Design of Normal Concrete Mixtures Using Workability-Dispersion-Cohesion Method
Authors: Qasrawi Hisham
Published: June 2016

The workability-dispersion-cohesion method is a new proposed method for the design of normal concrete mixes. The method uses special coefficients called workability-dispersion and workability-cohesion factors. These coefficients relate workability to mobility and stability of the concrete mix. The coefficients are obtained from special charts depending on mix requirements and aggregate properties. The method is practical because it covers various types of aggregates that may not be within standard specifications, different water to cement ratios, and various degrees of workability. Simple linear relationships were developed for variables encountered in the mix design and were presented in graphical forms. The method can be used in countries where the grading or fineness of the available materials is different from the common international specifications (such as ASTM or BS). Results were compared to the ACI and British methods of mix design. The method can be extended to cover all types of concrete.
Synthesis and Characterization of TiO2Modified with Polystyrene and Poly(3-chloro-2-hydroxypropyl Methacrylate) as Adsorbents for the Solid Phase Extraction of Organophosphorus Pesticides
Authors: Alejo-Molina Enrique , Vilchis-Néstor A. Rafael , Muñoz-Rodríguez David , Carrera-Figueiras Cristian
Published: June 2016

Novel hybrid TiO2particles were developed and assessed as an adsorbent for solid phase extraction (SPE) of organophosphorus pesticides (fensulfothion, parathion methyl, coumaphos, and diazinon) from spiked water. The sol-gel method was used to synthesize TiO2particles, which were coated with free-radical polystyrene (PS) and poly(3-chloro-2-hydroxypropyl methacrylate) (PClHPMA) polymers. Particle structures were determined via Fourier transform infrared spectroscopy to confirm that the polymers were successfully anchored to the TiO2particles. Thermogravimetric analysis was conducted to determine organic and inorganic matter in TiO2-PS and TiO2-PClHPMA particles showing results of 20 : 80 wt/wt% and 23 : 77 wt/wt%, respectively. SEM-EDS and X-ray diffraction test were conducted to determine the morphology and semielemental composition of the particles showing amorphous characteristics. By observing the contact angle, particles coated with PClHPMA were determined to be more hydrophilic than TiO2-PS particles. The pore size distributions obtained from the N2adsorption-desorption isotherms were 0.150 and 0.168 cm3g−1. The specific surface area (BET) was 239.9 m2g−1for TiO2-PS and 225.7 m2g−1for TiO2-PClHPMA. The synthesized particles showed relatively high yields of adsorption in SPE. The pesticide recoveries obtained by high performance liquid chromatography ranged from 6 to 26% for TiO2-PClHPMA and 44 to 92% for TiO2-PS.
Comparison of Different MPPT Algorithms with a Proposed One Using a Power Estimator for Grid Connected PV Systems
Authors: Hlaili Manel , Mechergui Hfaiedh
Published: June 2016

Photovoltaic (PV) energy is one of the most important energy sources since it is clean and inexhaustible. It is important to operate PV energy conversion systems in the maximum power point (MPP) to maximize the output energy of PV arrays. An MPPT control is necessary to extract maximum power from the PV arrays. In recent years, a large number of techniques have been proposed for tracking the maximum power point. This paper presents a comparison of different MPPT methods and proposes one which used a power estimator and also analyses their suitability for systems which experience a wide range of operating conditions. The classic analysed methods, the incremental conductance (IncCond), perturbation and observation (P&O), ripple correlation (RC) algorithms, are suitable and practical. Simulation results of a single phase NPC grid connected PV system operating with the aforementioned methods are presented to confirm effectiveness of the scheme and algorithms. Simulation results verify the correct operation of the different MPPT and the proposed algorithm.
A Case of Strangulated Urethral Prolapse in a Premenopausal Adult Female
Authors: Jessop Morris L. , Zaslau Stanley , Al-Omar Osama
Published: June 2016

Urethral prolapse in a premenopausal adult female is exceedingly rare. This paper describes a case of strangulated urethral prolapse presenting as a urethral mass in an unusual demographic and reviews the literature on etiology and management. Only a few cases have occurred in women of reproductive age. The etiology is likely multifactorial. Treatment with surgical excision provides good results in the majority of cases.
Effects of Shaoyao-Gancao Decoction on Infarcted Cerebral Cortical Neurons: Suppression of the Inflammatory Response following Cerebral Ischemia-Reperfusion in a Rat Model
Authors: Zhang Ying , Jia Xinling , Yang Jian , Li Qing , Yan Guofeng , Xu Zhongju , Wang Jingye
Published: June 2016

The mechanisms by which Shaoyao-Gancao decoction (SGD) inhibits the production of inflammatory cytokines in serum and brain tissue after cerebral ischemia-reperfusion (CI-RP) in rats were investigated. A right middle cerebral artery occlusion was used to induce CI-RP after which the rats were divided into model (n=39), SGD (n=28), clopidogrel (n=25) and sham operated (n=34) groups. The Bederson scale was used to evaluate changes in behavioral indices. The levels of IL-1β, TNF-α, MCP-1, IL-10, RANTES, VEGF, and TGF-β1 in the serum and infarcted brain tissues were measured. Nissl body and immunohistochemical staining methods were used to detect biochemical changes in neurons, microglial cells, and astrocytes. Serum levels of VEGF, TNF-α, MCP-1, IL-1β, and IL-10 increased significantly 24 h after CI-RP. In brain tissue, levels of TNF-αand IL-1βsignificantly increased 24 h after CI-RP, whereas levels of TGF-β1 and MCP-1 were significantly higher 96 h after CI-RP (P<0.05). SGD or clopidogrel after CI-RP reduced TNF-αand IL-1βlevels in brain tissue and serum levels of MCP-1, IL-1β, and IL-10. SGD increased the number of NeuN-positive cells in infarcted brain tissue and reduced the number of IBA1-positive and GFAP-positive cells. The efficacy of SGD was significantly higher than that of clopidogrel.
Hand Gesture Recognition Using Particle Swarm Movement
Authors: Nyirarugira Clementine , Choi Hyo-rim , Kim TaeYong
Published: June 2016

We present a gesture recognition method derived from particle swarm movement for free-air hand gesture recognition. Online gesture recognition remains a difficult problem due to uncertainty in vision-based gesture boundary detection methods. We suggest an automated process of segmenting meaningful gesture trajectories based on particle swarm movement. A subgesture detection and reasoning method is incorporated in the proposed recognizer to avoid premature gesture spotting. Evaluation of the proposed method shows promising recognition results: 97.6% on preisolated gestures, 94.9% on stream gestures with assistive boundary indicators, and 94.2% for blind gesture spotting on digit gesture vocabulary. The proposed recognizer requires fewer computation resources; thus it is a good candidate for real-time applications.
Effect of Perovskite Film Preparation on Performance of Solar Cells
Authors: Pei Yaxian , Zou Xiaoping , Qi Xiaolei , Teng Gongqing , Li Qi , Guo Dongdong , Zeng Shuangxiong
Published: June 2016

For the perovskite solar cells (PSCs), the performance of the PSCs has become the focus of the research by improving the crystallization and morphology of the perovskite absorption layer. In this thesis, based on the structure of mesoporous perovskite solar cells (MPSCs), we designed the experiments to improve the photovoltaic performance of the PSCs by improved processing technique, which mainly includes the following two aspects. Before spin-coating PbI2solution, we control the substrate temperature to modify the crystal quality and morphology of perovskite films. On the other hand, before annealing, we keep PbI2films for the different drying time at room temperature to optimize films morphology. In our trials, it was found that the substrate temperature is more important in determining the photovoltaic performance than drying time. These results indicate that the crystallization and morphology of perovskite films affect the absorption intensity and obviously influence the short circuit current density of MPSCs. Utilizing films prepared by mentioning two methods, MPSCs with maximum power conversion efficiency of over 4% were fabricated for the active area of 0.5 × 0.5 cm2.
Adaptive Robust Posture Control of a 3-RPS Pneumatic Parallel Platform with Unknown Deadzone
Authors: Tao Guoliang , Shang Ce , Meng Deyuan
Published: June 2016

An adaptive robust controller integrated with online deadzone estimation is proposed. This controller provides trajectory tracking control for pneumatic parallel mechanisms. Due to the air compressibility and nonlinear characteristics of the pneumatic system, unknown parameters in the model are selected to build online estimation matrices with the robust parts considered in the design. As each proportional valve has specific values of deadzone boundary points, the deadzone parts are integrated into the online estimator, and an inverse deadzone compensator is used to overcome nonlinear limitations. The effectiveness of the method was verified by simulation and experiment, and theoretical stability was demonstrated using the Lyapunov method. Experiments in an actual plant with the proposed controller indicated that the performance of the pneumatic platform can be as good as that of ideal deadzone inverse compensation. The deadzone estimated parameters converged to the real values quickly. Additionally, this algorithm was effective under a compound reference input trajectory; thus, the controller is expected to perform well in actual working situations.
Diagnosis ofXeroderma PigmentosumGroups A and C by Detection of Two Prevalent Mutations in West Algerian Population: A Rapid Genotyping Tool for the FrequentXPCMutation c.1643_1644delTG
Authors: Bensenouci Salima , Louhibi Lotfi , De Verneuil Hubert , Mahmoudi Khadidja , Saidi-Mehtar Nadhira
Published: June 2016

Xeroderma pigmentosum(XP) is a rare autosomal recessive disorder. Considering that XP patients have a defect of the nucleotide excision repair (NER) pathway which enables them to repair DNA damage caused by UV light, they have an increased risk of developing skin and eyes cancers. In the present study, we investigated the involvement of the prevalentXPAandXPCgenes mutations—nonsense mutation (c.682C>T, p.Arg228X) and a two-base-pair (2 bp) deletion (c.1643_1644delTG or p.Val548Ala fsX25), respectively—in 19 index cases from 19 unrelated families in the West of Algeria. For the genetic diagnosis ofXPAgene, we proceeded to PCR-RFLP. For theXPCgene, we validated a routine analysis which includes a specific amplification of a short region surrounding the 2 bp deletion using a fluorescent primer and fragment sizing (GeneScan size) on a sequencing gel. Among the 19 index cases, there were 17 homozygous patients for the 2 bp deletion in theXPCgene and 2 homozygous patients carrying the nonsenseXPAmutation. Finally,XPCappears to be the major disease-causing gene concerningxeroderma pigmentosumin North Africa. The use of fragment sizing is the simplest method to analyze this 2 bp deletion for the DNA samples coming from countries where the mutation c.1643_1644delTG ofXPCgene is prevalent.
Supervariable Approach to the Nilpotent Symmetries for a Toy Model of the Hodge Theory
Authors: Shukla D. , Bhanja T. , Malik R. P.
Published: June 2016

We exploit the standard techniques of the supervariable approach to derive the nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for a toy model of the Hodge theory (i.e., a rigid rotor) and provide the geometrical meaning and interpretation to them. Furthermore, wealsoderive the nilpotent (anti-)co-BRST symmetry transformations for this theory within the framework of the above supervariable approach. We capture the (anti-)BRST and (anti-)co-BRST invariance of the Lagrangian of our present theory within the framework of augmented supervariable formalism. We also express the (anti-)BRST and (anti-)co-BRST charges in terms of the supervariables (obtained after the application of the (dual-)horizontality conditions and (anti-)BRST and (anti-)co-BRST invariant restrictions) to provide the geometrical interpretations for their nilpotency and anticommutativity properties. The application of the dual-horizontality condition and ensuing proper (i.e., nilpotent and absolutely anticommuting) fermionic (anti-)co-BRST symmetries are completelynovelresults in our present investigation.
The Relationship of Oxidation Sensitivity of Red Blood Cells and Carbonic Anhydrase Activity in Stored Human Blood: Effect of Certain Phenolic Compounds
Authors: Huyut Zübeyir , Şekeroğlu Mehmet Ramazan , Balahoroğlu Ragıp , Karakoyun Tahsin , Çokluk Erdem
Published: June 2016

It has been reported that many modifications occur with the increase of oxidative stress during storage in erythrocytes. In order to delay these negative changes, we evaluated whether the addition of substances likely to protect antioxidant capacity in stored blood would be useful. Therefore, we investigated the effects of resveratrol, tannic acid, and caffeic acid in lipid peroxidation and antioxidant capacity of erythrocytes in stored blood. Donated blood was taken into four CPD containing blood bags. One bag was used as the control, and the others were supplemented with caffeic acid (30 μg/mL), resveratrol (30 μg/mL), and tannic acid (15 μg/mL), respectively. Erythrocyte lipid peroxidation, sensitivity to oxidation, glutathione levels and carbonic anhydrase, glutathione peroxidase, and catalase activities were measured on days 0, 7, 14, 21, and 28. In the control group, erythrocyte malondialdehyde levels and sensitivity to oxidation were increased whereas glutathione, glutathione peroxidase, and catalase levels were decreased (p<0.05). Resveratrol and caffeic acid prevented malondialdehyde accumulation and preserved glutathione, glutathione peroxidase, and catalase activities in erythrocytes. We demonstrated that resveratrol, caffeic acid, and tannic acid in stored blood could decrease the sensitivity to oxidation of erythrocytes in vitro but did not exhibit such effects on CA activity.
Design and Analysis of an Optical Coupler for Concentrated Solar Light Using Optical Fibers in Residential Buildings
Authors: Aslian Afshin , Honarvar Shakibaei Asli Barmak , Tan Chin Joo , Adikan Faisal Rafiq Mahamd , Toloei Alireza
Published: June 2016

Concentrated sunlight that is transmitted by fiber optics has been used for generating electricity, heat, and daylight. On the other hand, multijunction photovoltaic cells provide high efficiency for generating electricity from highly concentrated sunlight. This study deals with designing and simulating a high-efficiency coupler, employing a mathematical model to connect sunlight with fiber optics for multiple applications. The coupler concentrates and distributes irradiated light from a primary concentrator. In this study, a parabolic dish was used as the primary concentrator, a coupler that contains nine components called a compound truncated pyramid and a cone (CTPC), all of which were mounted on a plate. The material of both the CTPC and the plate was BK7 optical glass. Fiber optics cables and multijunction photovoltaic cells were connected to the cylindrical part of the CTPC. The fibers would transmit the light to the building to provide heat and daylight, whereas multijunction photovoltaic cells generate electricity. Theoretical and simulation results showed high performance of the designed coupler. The efficiency of the coupler was as high as92%, whereas the rim angle of the dish increased to an optimum angle. Distributed sunlight in the coupler increased the flexibility and simplicity of the design, resulting in a system that provided concentrated electricity, heat, and lighting for residential buildings.
A Novel Homozygous p.L539F Mutation Identified inPINK1Gene in a Moroccan Patient with Parkinsonism
Authors: Ben El Haj Rafiqua , Regragui Wafaa , Tazi-Ahnini Rachid , Skalli Asmae , Bouslam Naima , Benomar Ali , Yahyaoui Mohamed , Bouhouche Ahmed
Published: June 2016

Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer’s disease. Ten of fifteen causative genes linked to familial forms of PD have been reported to cause autosomal recessive forms. Among them, mutations in the PTEN-induced kinase 1 (PINK1) gene were shown to be responsible for a phenotype characterized by early onset, good response to levodopa, and a benign course. Using chromosomal microarray analysis and Sanger sequencing, we identified a homozygous G/C substitution in a 58-year-old Moroccan man diagnosed with recessive inherited Parkinson’s disease. This G-to-C transition occurred at position 1617 leading to an amino acid change L/F at position 539 located in highly conserved motif in the C terminal sequence ofPINK1. Interestingly, the c.1617G>C substitution is absent in 192 ethnically matched control chromosomes. Our findings have shown that the p.L539F is a novel mutation located in the C terminal sequence of the PINK1 protein that could be pathogenic and responsible for a clinical phenotype resembling idiopathic Parkinson’s disease with rapid progression and early cognitive impairment.