bluuebunny/crossref_metadata_2025 huggingface dataset:
Boundary layer flow over a moving plate in MHD Jeffrey nanofluid: A revised model
Authors: Zokri S M , Arifin N S , Kasim A R M , Mohammad N F , Salleh M Z
Published: August 2018

The flow and heat transfer of magnetohydrodynamic (MHD) Jeffrey nanofluid induced by a moving plate is examined numerically. The formulation is established by using the revised model of passively controlled boundary layer instead of actively, which is more realistic physically. The similarity transformation variables are used to transform the partial differential equations into a set of ordinary differential equations before solving it via numerical approach called as the Runge-Kutta Fehlberg method. Graphical representation of the physical parameters over the temperature profile is deliberated. Temperature profile is slowed down due to the parameters of Deborah number and plate velocity while the reverse trend is observed for thermophoresis diffusion parameter. The Brownian motion has shown an insignificant outcome on the temperature profile. A comparison with the earlier publication has been conducted and a perfect agreement between the data is detected.
Stationary queue length of a single-server queue with negative arrivals and nonexponential service time distributions
Authors: Koh S K , Chin C H , Tan Y F , Teoh L E , Pooi A H , Goh Y K
Published: August 2018

In this paper, a single-server queue with negative customers is considered. The arrival of a negative customer will remove one positive customer that is being served, if any is present. An alternative approach will be introduced to derive a set of equations which will be solved to obtain the stationary queue length distribution. We assume that the service time distribution tends to a constant asymptotic rate when time t goes to infinity. This assumption will allow for finding the stationary queue length of queueing systems with non-exponential service time distributions. Numerical examples for gamma distributed service time with fractional value of shape parameter will be presented in which the steady-state distribution of queue length with such service time distributions may not be easily computed by most of the existing analytical methods.
Analysis and test for thermal performance of High Altitude Super Pressure Balloons during ascending process
Authors: Zhao Da , Liu Dong-xu , Feng Kai , Zhu Ming
Published: August 2018

A two-node model for thermal characteristics and a dynamic model of High Altitude Super Pressure Balloon (HASPB) during ascending process are established. The thermal performance of HASPB during ascending process is analyzed. Several simulations are conducted under the same conditions with the real flight test. Results show that supercool phenomenon occurs during ascending caused by free expansion of gas, and the value is about 10-15 K. Once the balloon reaches the design height and becomes over-pressured, the temperature of balloon rises rapidly, and this adjustment process lasts for about 10 minutes. The real flight test to 20000 m validates the reliability of the two-node model.
Asynchronous differential evolution with selfadaptive parameter control for global numerical optimization
Authors: Jong Choi Tae , Lee Yeonju
Published: August 2018

In this paper, we propose an extended self-adaptive differential evolution algorithm, called A-jDE. A-jDE algorithm is based on jDE algorithm with the asynchronous method. jDE algorithm is one of the popular DE variants, which shows robust optimization performance on various problems. However, jDE algorithm uses a slow mutation strategy so that its convergence speed is slow compared to several state-of-the-art DE algorithms. The asynchronous method is one of the recently investigated approaches that if it finds a better solution, the solution is included in the current population immediately so it can be served as a donor individual. Therefore, it can improve the convergence speed significantly. We evaluated the optimization performance of A-jDE algorithm in 13 scalable benchmark problems on 30 and 100 dimensions. Our experiments prove that incorporating jDE algorithm with the asynchronous method can improve the optimization performance in not only a unimodal benchmark problem but also multimodal benchmark problem significantly.
The influence of CDN sinking on metro transmission network
Authors: Hu Y. , Peng P.
Published: August 2018

With the rise of VR/AR and 4K/8K video services, users have higher requirements for personal experience. Promotion of user experience is an important factor to attract end-users. Compared with traditional website access, the deployment of CDN has advantages of improving access speed, solving the problem of high traffic and large concurrency, improving the reliability of data sources. CDN’s basic characteristics can be summarized as: cache contents in different locations, and load requests of users to the most appropriate cache server through load balancing technology. The traditional networking mode deployed CDN on the core layer leads to contents away from the end users. This means the probability of occurrence of congestion increased, and the end-to-end delay enhanced. Therefore, CDN sink to the convergence layer and even edge layer can be considered to solve problems such as web browsing slow, video buffer in slow and so on. The sinking of CDN has a profound impact on the network structure, basic resources and network intellectualization. Large capacity PTN/OTN equipment should be deployed on each layer. The sinking of CDN leads to the flattening of the network. The basic resources of metro transport network such as computer room space, air conditioning, power supply must ensure the normal operation of the sinking CDN equipments and transmission equipments. SDN/NFV technology should be introduced to transmission network in the future.
High-order neural network in entity relationship extraction
Authors: Liu Wei , Chen Hongchang , Huang Ruiyang
Published: August 2018

In this paper, a kind of high-order neural network is proposed to extract entity relations in natural language. In this kind of network, different parameters absorb non-overlapping information from separated data respectively, which makes parameters more significant for understanding. This neural network can alleviate overfitting problem in some degree. When solving the task of entity relationship extraction, this network can give a result no worse than current methods.
Network selection algorithm based on decision tree in heterogeneous wireless networks
Authors: Li Wang-hong , Qi Zhu
Published: August 2018

A network selection algorithm based on Decision Tree is proposed to solve the problem. Users can select the appropriate network according to their service characteristics and requirements when they decide which network to access. First, we get the training data under the Interactive Class service from the synergetic algorithm which can be used for training set. The network attributes are used for attribute set. And then we can choose the attribute with the largest information gain as the division attribute after the discretization of continuous features by the bisection method. Keep going this step recursively, we can finally get a decision tree with high generalization ability by which we can make the network selection. Simulation results show that the algorithm we proposed is simple and effective and demonstrate the effectiveness of our scheme in improving the quality of service according to the user requirements under the Interactive Class service.
Design and implementation of an Agricultural IoT based on LoRa
Authors: Jin Jin , Ma Yajie , Zhang Yingcong , Huang Qihui
Published: August 2018

In order to build a large-scale Agriculture IoT, a sensor network based on LoRa is designed instead traditional Zigbee network. The data collected by the sensors is transmitted to remote server for storage through GPRS. The environment data is displayed on the browser for users to use. Because the agricultural production environment is complex, collected data is greatly influenced by noise and can not be analyzed directly. To solve this problem, the time series analysis method is used to model the raw data and a prediction model is obtained, which can fill or replace the missing data, abnormal data and so on, and can effectively predict the future data. It provides a good data source for the analysis of subsequent data. The experiment shows that the system can satisfy the design requirements and can operate efficiently and steadily.
Synthesis of cellulose from office waste paper and the effect on mechanical properties of cellulose/kenaf/epoxy composite
Authors: Vicki. W.V. , Santhana Rajah Taness , Selvakumar. S.
Published: August 2018

Environmental and open public health aspects have an important and increasing role, especially in the exploration of natural fibers from recycle materials. The aim of this study is to synthesis cellulose from office waste paper and use it as a reinforcement filler to develop biocomposites. Epoxy reinforced kenaf fiber and cellulose composite were prepared in this study using polymer casting technique consisting of grinded kenaf fibre (natural fibre) 5% and epoxy 95% as reinforcement element. Cellulose was synthesized from recycled office papers and used as a filler to prepare cellulose/kenaf reinforced epoxy composite. Effect of cellulose to the mechanical properties of the composite were investigated. Samples were fabricated by weight percentage of 0%, 0.5%, 1.0%, 1.5% and 2.0% of cellulose content. For mechanical properties impact test, Rockwell harness and tensile testings were conducted.
The role of sales effort on manufacturer's channel strategies
Authors: Li Baixun , Chen Guo , Nan Yaru
Published: August 2018

Competing manufacturers, who sell their products through retailers, may face the strategic distribution channel design question of whether to establish an “store-within-store” channel or not. With consider of the role of sales effort, we analyze the manufacturer channel strategies. Two cases are considered: competing manufacturer and competing retailer. We built four game models corresponding to four channel strategies, and discussed the influence of manufacture's bargaining power coefficient, prices competition intensity, and sales effort competition intensity on manufactures' channel strategies.
Fast analytical calculation of the air-gap flux density in an outer-rotor permanent-magnet brushless motor
Authors: Ye Shuaichen , Yao Xiaoxian
Published: August 2018

The air-gap flux density must be considered in the design and optimization of the structure parameters of permanent-magnet brushless motors (PMBMs). Existing methods for calculating the air-gap flux density are complex and thus cannot be easily applied in practical engineering. This paper presents a fast analytical method for calculating the air-gap flux density that is more efficient and practicable than existing methods. A lumped magnetic circuit model is presented to illustrate the proposed method. Then, the analytical result and finite element analysis (FEA) results obtained for a PMBM prototype are compared. The results indicate that the error between the two methods does not exceed 5%. Therefore, the proposed analytical method is highly efficient and accurate, which may be applied in the motor pro-design process of many engineering instruments.
Investigation of the effect of the angle between drive shafts on vibration responses of main reducer
Authors: Liu Xiaogang , Wu Zhaoyu , Shu Weiguang , Lu Jie
Published: August 2018

The drive shaft arrangement has a considerable influence on the vibration responses of the shaft-final drive system. In this research, a coupled vibration model is developed based on force analysis of hypoid gear and lumped mass method. The effect of time-varying mesh stiffness, gear backlash and transfer error are included to investigate the effect of the angle between drive shafts on vibration responses of main reducer. The vibration responses of main reducer are acquired using this model. The results show that the vibration amplitude of the gears of main reducer increase with the angle between drive shafts. This paper presents an analytical method to determine the value of the angle between drive shafts, so as to control the vibration of main reducer.
Flow boiling instabilities of nitrogen in horizontal small diameter tube
Authors: Zhang Qiaoyu , Liu Jianjun
Published: August 2018

The flow boiling instability characteristics of nitrogen flow boiling in a horizontal small diameter tube were numerically studied, and a numerical model coupled with two phase flow boiling and system flow supplying was developed. With the steady state solution of the model, the flow boiling characteristic curve and flow supplying curve were obtained. The flow boiling characteristic curve was affected by the heat flux and inlet subcooling, meanwhile the flow supplying curve was affected by the total system pressure drop and friction feature of the flow supplying section. With the transient solution of the model, The dynamical response of pressure drop oscillations type (PDOs) instability of two phase flow were investigated, occurring region and trigging conditions were also obtained.
The inverse kinematics analysis and simulation study on the controllable loading mechanism
Authors: Zhang Lin , Wu Cheng-ge , Cai Gan-wei
Published: August 2018

The multi-DOF controllable loading mechanism adopts the electric drive system to replace the hydraulic drive system of traditional loader, not only has higher transmission efficiency and has better mechanical and electrical integration level, but also overcome the shortcomings of high cost of manufacture and maintenance.The inverse kinematics model of this type of loading mechanism was built by means of closed loop vector method. According to the performance index of the loading mechanism, the inverse kinematics model was solved by means of MATLAB software, and the input motion law of the two driving lever at different period of time is obtained, and a small prototype is built, which provides the basis for control system programming of this new type of leading mechanism. To some extent, this research lays a foundation for further development of this type of loading mechanism.
Effect of bonding agent production materials on the mechanical properties of composite solid rocket propellant
Authors: elall Ali.M.Abd , Lin Guo
Published: August 2018

An effective pathway was explored to design and select proper bonding agents that could effectively improve the interfacial interactions between bonding agents and solid particles, modern types of composite solid propellants focused on increasing the mechanical properties in order to withstand stresses produced due to various loading conditions, changes in environmental condition, transportation and handling. In this work, the study show that the effect of solvent in production of bonding agent has a different impact on the mechanical properties as the polar solvent in formulation S3 has a good strain values corresponding to the stress. Also the changing of the percentage of CuCl2 has a significant effect on mechanical properties as giving high value of strain with the percentage of 4.5 % and returns back the value of strain decrease with increase the percentage of CuCl2 to give the lowest values of the strain corresponding to the stress value with percentage 7.5 %.
Study of the reversing mechanism of wetting agent adding device based on Adams simulation
Authors: Gao Guijun , Dong Qiang
Published: August 2018

This paper proposed a hydraulically-driven adjustable concentration of wetting agent adding device applied in underground of coal mine. A 3D model of the reversing mechanism of adding device was
built by using Solidworks, and then imported to the Adams to build a virtual prototype model. The reversing mechanism was optimized by setting the model parameters, adding constraints and drive. The dynamic characteristics of the reversing mechanism were analysed under different length l of the driven rocker arm. The results show that the value of l (l=17mm) can realize automatic reversing. The simulation results provide a basis for trial-manufacture of physical prototyping and optimized design.
Analysis of traffic-related air pollution using Shanghai road traffic state index
Authors: Chen Ruoyu , Chen Lianliang , Fan Wenhao
Published: August 2018

Recently, due to the rapid economic development and the acceleration of urbanization, haze events have occurred frequently in most parts of China, which has attracted widespread attention at home and
abroad. This study presents a statistical summary of air pollution concentrations and traffic state indexes from August 2014 to April 2015 in Shanghai, China. We find PM2.5 concentrations show a remarkable seasonal variability with ``winter > spring > autumn > summer'' in Shanghai. Concentrations of PM2.5, CO, NO2, SO2 are generally higher in winter than in summer due to enhanced anthropogenic and biogenic emissions and unsuitable meteorological conditions for pollution diffusion, contrary to concentrations of O3. The weekly changes of NO2 are highly consistent with that of traffic state indexes, suggesting a significant contribution to NO2 concentrations from road traffic emissions. Two moderate peaks are found in the diurnal variability of concentrations of PM2.5, CO and NO2, similar to road traffic indexes, indicating the important contribution of road traffic emissions every day. We find that SO2, NO2, CO are the dominant factors contributing to PM2.5 pollution, where NO2 and CO are mainly from road traffic emissions. The average annual Spearman correlation coefficient is r = 0.689 (p < 0.01), r = 0.564 (p < 0.01), r = 0.812 (p < 0.01), respectively.
Predicting the travel time of arterial traffic using particle filter with speed matrix
Authors: Yang Qiangrong , Peng Qi
Published: August 2018

Travel time prediction is an essential part of intelligent transportation system applications. However, the existing travel time prediction methods mainly focus on the freeway due to its simplicity and the high coverage of sensors and few researches have been conducted for the urban arterial road. Consequently, a travel time prediction algorithm based on particle filter is proposed in this paper to predict short-term travel time of the arterial traffic with historical floating car data and the concept of speed matrix is developed to illustrate the spatiotemporal properties of the arterial traffic. Unlike previous travel time prediction methods, the proposed algorithm uses particles with corresponding weights to model the traffic trend in the historical data instead of state-transition function and the weight for each particle are calculated with similarities between the speed matrix of the particle and the current traffic pattern. Moreover, a resampling process is developed to solve the degeneracy problem of the particles by replacing the low-weight particles with historical data. A real floating car dataset of 10357 taxis over a period of 3 months within Beijing is utilized to evaluate the performances of the algorithms. The proposed algorithm has the least errors by comparing with other three algorithms.
E-Government for human capability development program: An implementation of G2E System for enhanced government services
Authors: Mapanoo Ma. ELiza D. , Caballero Jonathan M.
Published: August 2018

e-Government for human capability development program: an Implementation of G2E System for enhanced government services is design for Local Government Unit (LGU) which will enable every government employee to have an equal chance of providing services to their clientele and management. Philippines has been one of the countries promoting e-government where people linked to government agencies through the aid of network infrastructure, web technologies and database management. The system is designed and patterned to PRIME (Program to Institutionalize Meritocracy and Excellence in Human Resources Management) module, releases by Philippine Civil Service Commission which assures and safeguards smooth operations and procedures are done in every local government in both cities and municipalities. The system was test both in municipality and city to determine the readiness of its design and algorithm in handling government human resources management process. The design based on ISO 9126 yield a very good response from the respondents.
Sentiments classification in stock network public opinion space based on long-short
memory convolution neural network
Authors: Zhang Gaowei , Xu Lingyu , Wang Lei
Published: August 2018

Deep learning is used to deal with natural language processing problems. Some are based on phrases and some are based on words. This article is inspired by the pixel level in the CV world and therefore retrains the neural network from a character perspective. Neural networks do not need to know about word lookup table or word2vec in advance, and the knowledge of these words is often high-dimensional and it is difficult to apply to convolutional neural networks. In addition, our long-short term memory convolutional neural networks no longer need to know the syntax and semantics in advance. The purpose of this paper is to analyse the investor's psychological characteristics and investment decision-making behaviour characteristics, to study the investor sentiment in the network public opinion space.
Research on E-sports session identification
Authors: Yu Cheng , Wan Ning Zhu , LiuLei Li , Yu Meng Sun , Nong Liqing
Published: August 2018

With the development of the e-sports, data analysis has gained more and more attention in the use of it. For the important problem that the analysis of behaviour patterns of the e-sports’ individual character is not solved directly and solved by anyone, this paper has put forward the session partitioning algorithm based on heat maps of jungle which adopts the clustering prototype thinking that partitions spatial range in advance and then determines by the range of time threshold. Experiments show that it solves the problem of roles of the session which is difficult to be partitioned.
LBS privacy protection technology based on searchable encryption mechanism
Authors: Feng Tao , Wang Xudong , Li Xinghua
Published: August 2018

Location based Service (the Location - -based Service, LBS) is a System is to transform the existing mobile communication network, wireless sensor networks, and Global Positioning System (Global Positioning System, GPS) with the combination of information Service mode, the general improvement in Positioning technology and the high popularity of mobile intelligent terminals, led to the growing market of LBS. This article from the perspective of LBS service privacy security, mainly studies the LBS location privacy protection scheme based on cipher text search, in LBS service location privacy and search information privacy issues, focus on to design the scheme, based on the cryptography in LBS service privacy protection issues in the process, this paper fully and secret cipher text search characteristics, design a new privacy protection of LBS service model, and expounds the system structure and working principle of model, defines the security properties of the privacy protection model and security model, Under the specific security assumptions, the new location privacy protection scheme based on lbspp-bse (LBS location privacy protection based on searchable encryption) is implemented.
Applying deep learning for adverse pregnancy outcome detection with pre-pregnancy health data
Authors: Mu Yu , Feng Kai , Yang Ying , Wang Jingyuan
Published: August 2018

Adverse pregnancy outcomes can bring enormous losses to both families and the society. Thus, pregnancy outcome prediction stays a crucial research topic as it may help reducing birth defect and improving the quality of population. However, recent advances in adverse pregnancy outcome detection are driven by data collected after mothers having been pregnant. In this situation, if a bad pregnancy outcome is diagnosed, the parents will suffer both physically and emotionally. In this paper, we develop a deep learning algorithm which is able to detect and classify adverse pregnancy outcomes before parents getting pregnant. We train a multi-layer neural network by using a dataset of 75542 couples’ multidimension pre-pregnancy health data. Our model outperforms some of algorithms in accuracy, recall and F1 score.
A centralized secure plan for detecting and mitigation incidents in hybrid SDN
Authors: Zkik Karim , EL Hajji Said , Orhanou Ghizlane
Published: August 2018

The information technology sector has experienced phenomenal growth during recent years. To follow this development many new technologies have emerged to satisfy the expectations of businesses and customers, such as Cloud Computing, mobility, virtualization, Internet of things and big data. Traditional network cannot longer support this growth and suffers more and more in terms of misconfiguration,management and configurations complexity. Software defined network (SDN) architectures can be considered as a big revolution in the field of computer networks, because they offer a centralized control on infrastructure, services and the applications deployed which facilitate configuration and management on the network. The implementation of this type of architecture is not obvious and requires great expertise and good handling and management of network equipment. To remedy this problem the SDN architectures have evolved towards distributed and hybrid architectures. Despites the advantages of using SDN, security issues remain a real obstacle in front of the deployment of this type of architecture. The centralized architecture of this type of networks makes it vulnerable to several types of attacks and intrusions, and the implementation of security equipment generally causes a decrease in performance and increase latency.
Practical output tracking for a class of uncertain nonlinear time-delay systems via state feedback
Authors: Alimhan Keylan , Otsuka Naohisa , Kalimoldayev M.N. , Tasbolat N.
Published: August 2018

In this paper, the problem of global practical output tracking is investigated by state feedback for a class of uncertain nonlinear time-delay systems. Under mild conditions on the system nonlinearities involving time delay, we construct a homogeneous state feedback controller with an adjustable scaling gain. By a homogeneous Lyapunov-Krasovskii functional, the scaling gain is adjusted to dominate the time-delay nonlinearities bounded by homogeneous growth conditions and render the tracking error can be made arbitrarily small while all the states of the closed-loop system remain to be bounded.
Aligned magnetic field flow of Williamson fluid over a stretching sheet with convective boundary condition
Authors: Arifin N S , Zokri S M , Kasim A R M , Salleh M Z , Mohammad N F
Published: August 2018

The analysis on mathematical model of Williamson fluid on the convective boundary layer flow and heat transfer over a horizontal stretching sheet has been carried out. The model is constructed by introducing the aligned magnetic field on the flow region under the case of convective boundary conditions which is implies the fluid heated from the stretching surface. The numerical method of Runge-Kutta Fehlberg (RKF45) is employed to the ordinary differential equations after being transformed from the governing equations by using suitable similarity transformation. The solutions of several influencing parameters on the velocity and temperature profiles are discussed and displayed in graphical form. The results of this study indicate that the increasing magnetic field parameter decreases the fluid velocity which suppressed the fluid motion.
Electron transport coefficients in binary mixtures of tetramethylsilane gas with Kr, Xe, He and Ne gases
Authors: Thi Tuoi Phan , Xuan Hien Pham , Anh Tuan Do
Published: August 2018

Tetramethylsilane, alone and in combination with inert gases are widely used in various material processing. The electron transport coefficients in binary mixtures tetramethylsilane gas with buffer gases such as Kr, Xe, He, and Ne gases, therefore, was firstly calculated and analyzed by a two-term approximation of the Boltzmann equation in the E/N (ratio of the electric field E to the neutral number density) range of 0.1-1000 Td (Townsend). These results can be considered to use in many industrial applications depending on particular application of gas, especially on plasma polymerization and plasma enhanced chemical vapour deposition.
Research on fiber coupling technology of kilowatt laser diode by single emitters
Authors: Qin Wenbin , Li Jing , Yao Lei , Liu Youqiang , Qiu Yuntao , Wang Zhiyong
Published: August 2018

This paper proposes a program that combine the laser of single-emitters by using fiber combiner, what’s more, we designed and developed a multiple single emitters diode laser module of full optical fiber. We used ZEMAX software to simulate and optimize the influence of fiber coupling efficiency by the location of cylindrical lens and fiber, finally, we developed 8W fiber coupling single emitter diode laser, the wavelength is 915nm, fiber diameter is 105/125μm, NA0.15. This article also carried on the theoretical research of N×1 fiber combiner, and based on Vytran GPX glass processing system, we fabricated the 19×1fiber combiner by TFB technique, combined 19 105/122μm, NA0.15 fibers to a 400/440μm, NA0.22 fiber, has realized 150W laser output, with fiber combining efficiency more than 96%. In the end, 8*400um fibers are synthesized through a fiber taper. The output laser power after fiber taper reached 1453W, with the focus spot size is 2.25mm*1.1mm and power density reached 6×104W/cm2.
Damage detection of cracks in carbon fibre reinforced composites by pulsed eddy-current testing
Authors: Aoukili Abdeslam , Khamlichi Abdellatif
Published: August 2018

Non-destructive evaluation techniques that are based on electromagnetic methods are commonly used for inspection of metallic and carbon fibre reinforced plastics parts. Some of these inspection methods are based on eddycurrents which are generated by the electromagnetic induction phenomenon occurring under variable magnetic induction field. In eddy-currents testing, the depth of penetration into the material is controlled by the conductivity of the tested material and also the work frequency. Transient eddy-currents, also called pulsed eddy-currents, is an emerging non destructive technique that employs a pulsed excitation to induce a transient electromagnetic response from defects lying deep within a conducting structure. Such defects are difficult to inspect by conventional techniques, such as harmonic eddy-currents or ultrasonics. A large number of recent scientific publications have dealt with the theoretical understanding of the pulsed eddy-currents phenomenon and have also undertaken the design feature of appropriate probes. Finite element solution of the governing equations has been used to simulate the output signals as function of the input electrical excitation signal. Considering a B-scan strategy, simulation of a pulsed eddy-currents based probe is performed in this work with the objective to assess detectability of small defects through monitoring impedance changes of a detection probe.
Bridge deck condition assessment by using GPR: a review
Authors: Bachiri Tahar , Khamlichi Abdellatif , Bezzazi Mohammed
Published: August 2018

Bridge deck deterioration includes delamination, corrosion of rebars, vertical cracking and concrete degradation. Ground Penetrating Radar based inspection technique was used for mapping bridge deck in order to monitor the health of this vital structure. Beginning from the 1970‘s, research has focused on identification of bridge deck deterioration which causes severe deficiencies by reducing seriously strength. The main purpose of this work was to review the literature existing in the field of bridge deck diagnosis by means of Ground Penetrating Radar. This enabled to survey detailed evolution of this technique, to understand the effects of key intervening parameters and to determine the kind of material disorders that this device could be used for. Bridge deck condition assessment can then be performed more successfully, based on the huge progress experienced by this particular method of inspection.
Micromechanical modelling of porous viscoelastic composite materials
Authors: El Kouri Mohamed , Bakkali Abderrahmane , Azrar Lahcen
Published: August 2018

Modelling and predicting the effective behavior of non-ageing viscoelastic composites have attracted the attention of many researchers. Actually, predicting the effective behavior and the macroscopic overall response while taking into account the constituents properties and shape of inclusions as well as their volume fractions is a challenging topic. In this work, porous viscoelastic composites are considered. The porous effect is introduced as a solid voided inclusions embedded in a viscoelastic matrix. The effective behavior is modelled by delayed integropartial differential equations. The resolution of the resulting equations is done through a methodological approach based on the Volterra tensorial products and the dynamic Green‘s tensor. Thus, the localization equations relating the local and the global fields are derived. After that, the Mori-Tanaka mean field micromechanical model assumptions are applied to derive the Mori-Tanaka‘s localization tensor. Once this step is completed, the effective properties are obtained through mean field techniques. The effective properties are given through tensorial convolution products. A numerical algorithm is elaborated for the computation of direct and inverse tensorial convolution products. For the validation of the developed modelling a comparison with Laplace-Carson approach is done.
Detection of rebar corrosion in bridge deck by using GPR
Authors: Bachiri Tahar , Khamlichi Abdellatif , Bezzazi Mohammed
Published: August 2018

Ground Penetrating Radar based inspection technique is currently used for mapping bridge deck in order to monitor the health of this vital structure. Research over recent years in this field has focused on identification of rebar corrosion which is known to cause staged deficiencies by reducing bridge deck strength to critical levels. It is expected that using high-frequency antennas could improve discrimination of anomalies and enhance detection of small corrosion defects affecting bridge deck rebars. In this work, simulation of the input reflection coefficient of reinforced concrete bridge deck as modified by corrosion of a steel rebar is performed. The objective is to analyse the effect of the work frequency and corrosion layer thickness on the input reflection coefficient. Simulations have been carried out for various situations involving intact and corroded zones of a rebar buried in a reinforced concrete plate with the whole infrastructure overlaid by an asphalt layer. The obtained results have shown that the value of work frequency is very important and should be carefully selected.
Robustness of ultrasonic detection of flaws by using synthetic aperture focusing technique
Authors: Rejani Sofia , Khamlichi Abdellatif , El-Hajjaji Abdellah
Published: August 2018

One of the challenging problems in non-destructive evaluation is related to identification and sizing of flaws. A high resolution image of the scanned part is required. This allows, through using adequate post-processing of data, to perform localisation and sizing of a flaw. Several techniques have been introduced recently for this purpose. These include among others the synthetic aperture focusing technique, inverse wave-field extrapolation and the total focusing method. However, large uncertainties are affecting the inverse problem solution as provided by these methods when dealing with small defects. It was recognized that reconstruction based on the ultrasonic synthetic aperture focusing technique elaborated in frequency domain provides high resolution imaging even at large distances. This work focused on this promising procedure for the special case of ultrasonic imaging of flaws in 2D elastic medium under plane strain conditions, where the image is provided by a B-scan. Robustness of detection was investigated through perturbing the radargram by white noise and assessed as function of noise energy. It was found that synthetic aperture focusing technique is insensitive to noise.
Structural, optical and electrical characterizations of ZnO/PS
Authors: Yamlahi Alami Zineb , Salem Moez , Gaidi Mounir , El khamkhami Jamal
Published: August 2018

This work reported on solar cell ZnO/PS heterojunction fabricated from Zinc nitrate with molar concentrations 0.05M and 0.2M using spray pyrolysis technique, to study the effect of high and low molar concentration of Zn precursor on structural, optical and electrical properties. The structural analyse showed that the obtained thin films deposited on glass substrate were polycrystalline with a hexagonal wurtzite structure and preferentially oriented along the c-axis direction, while structural properties enhanced with higher morality 0.2M. Roughness surface of ZnO/PS HJ increased widely with higher morality. Through I-V characteristics, the enhancement of electrical properties with higher molarity has been achieved. Isc get augment from 23mA/cm2, to 27mA/cm2, and Voc from 551mV to 554mV when molarity has taken values 0.05M and 0.2M respectively. Ideality factor has influenced by molarity variance too. The impact of solar irradiance G and temperature T on solar cell fabricated from 0.2M molarity has been investigated. The current density increased from 13.53 mA/cm2 to 27mA/cm2, the voltage from 525mV to 546mV, and the efficiency from 5.2% to 10.9% when the solar irradiance have increased from 500 to 1000W/m2. The temperature also influences on the solar cell behaviours, especially the voltage is enhanced by temperature increasing.
Moroccan Cedar softwood study: Application of FT-Raman spectroscopy
Authors: Fellak Somia , Boukir Abdellatif
Published: August 2018

As non-destructive technique, FT-Raman spectroscopy has been used to study the molecular structure and monitor changes in the composition of carbohydrates and lignin components containing wood materials. For this purpose, four samples originated from Moroccan cedar wood were analyzed. Following the FT-Raman spectra, it was found that carbohydrates were identified by the bands at 898, 1098, 1123 and 1456 cm-1, while lignin matrix was evaluated by the bands at 1657, 1598 and 1267 cm-1. The decrease of the intensities related to these feature bands reflects the effects of natural degradation phenomenon and shows the evidence of chemical changes and quick deterioration of these contents upon exposure time to natural degradation process. Thus, the FT-Raman tool has the potential to be one of crucial sources to characterize composite materials and to evaluate the chemical changes occurred on their structures under the influence of physico-chemical or biological attacks without causing any damage of the wood surfaces or their supports.
Memory Impairment Allied to Temporal Lobe Epilepsy and its Deterioration by Phenytoin: A Highlight on Ameliorative Effects of Levetiracetam in Mouse Model
Authors: Mohan Asher , Krishna Kamsagara
Published: August 2018

Background/Objectives Memory impairment (MI) and epilepsy go hand in hand, mainly in conditions of temporal lobe epilepsy (TLE). This disease comorbidity has been reported to worsen upon treatment. Hence this study aims to evaluate the extent of aggravating effect of phenytoin (PHT) at normal and reduced doses on MI associated with TLE and additionally assesses the protective effect of levetiracetam (LEV) on these adverse effects.

Methods Swiss albino mice of either sex (n = 36) were used for this study in which seizures were induced by intraperitoneal administration of pilocarpine (300 mg/kg i.p.) followed by evaluation of antiepileptic activity by technique of Racine's scale for convulsive scores. Errors (a factor denoting MI) were assessed using radial arm maze. Finally brain biochemical measures of acetylcholinesterase and glutamate along with cresyl violet staining and estimation of total neuronal number of the hippocampus were performed.

Results Exacerbation of MI by PHT was observed, where the extent of MI was found to be lesser in the reduced dose approach (PHTR: 28.50 ± 1.03; p ≤ 0.05). However, this tactic in dose reduction was interfered with the antiepileptic potential of the drug. Attenuation of MI upon combining with LEV, without an interference in the principal treatment, was observed equally in the behavioral and brain aspects of the study (PHTN + LEV: 1.33 ± 0.33 and PHTR + LEV: 1.00 ± 0.17; p ≤ 0.05).

Conclusions The promising effects of LEV could thus aid in proposing a new management remedy for TLE to minimize the adverse effect associated with it.
Arterial Endovascular Interventions in Acute Mesenteric Ischemia
Authors: Miller Geoffrey , Stone James , Wilkins Luke
Published: August 2018

Acute mesenteric ischemia (AMI) is a true medical emergency and requires a multi-disciplinary treatment approach. AMI occurs when there is a sudden decrease in blood flow resulting in hypoperfusion to the intestines and may lead to bowel infarction. There are many potential etiologies of AMI that include arterial embolus, arterial, or venous thrombosis; traumatic injury; aortic dissection; intestinal obstruction; non-occlusive mesenteric ischemia, and vasculitis. Given mortality rates that approach 90%, rapid diagnosis is essential to decrease risk of bowel infarction. While surgical management has traditionally been the treatment of choice, endovascular management is being used with increasing frequency. Further, utilizing endovascular treatment options together with surgical intervention has shown promising results. The endovascular approach to treatment of AMI will depend on the underlying etiology. In addition, the acuity of patient presentation, presence, or absence of bowel infarction; patient stability; and availability of a hybrid operating room will influence the treatment plan of a patient with AMI. Early diagnosis with advanced cross-sectional imaging along with assessment of the underlying risk factors will optimize chances of early intervention and improve patient outcomes.
Klassifikation subaxialer Halswirbelsäulenverletzungen
Authors: Schopper Clemens , Schultheiss Markus
Published: August 2018

Im klinischen Alltag wurden Verletzungen der unteren Halswirbelsäule lange Zeit analog zu den Brust- und Lendenwirbelsäulenverletzungen gemäß der AO-Klassifikation beschrieben. Im Rahmen dieser Übersicht wird nun die neue AOSpine-Klassifikation für Verletzungen der subaxialen Halswirbelsäule vorgestellt.
A systematic approach to optimize excitations for perturbative transport experiments
Authors: van Berkel M. , de Cock A. , Ravensbergen T. , Hogeweij G. M. D. , Zwart H. J. , Vandersteen G.
Published: August 2018

In this paper, techniques for optimal input design are used to optimize the waveforms of perturbative experiments in modern fusion devices. The main focus of this paper is to find the modulation frequency for which the accuracy of the estimated diffusion coefficient is maximal. Mathematically, this problem can be formulated as an optimization problem in which the Fisher information matrix is maximized. First, this optimization problem is solved for a simplified diffusion model, while assuming a slab geometry and a semi-infinite domain. Later, the optimization is repeated under more general conditions such as a cylindrical geometry, finite domain, and simultaneous estimation of multiple transport coefficients. Based on the results of these optimizations, guidelines are offered to select the modulation frequency and to determine the optimality of the corresponding experiment.
A sensitive, low noise, DC to 12 MHz, large area photodiode preamplifier for photothermal heterodyne imaging
Authors: Zeng Zhi-Cong , Schultz Zachary D.
Published: August 2018

We report a compact, fast, and low-noise large area photodiode preamplifier designed for photothermal heterodyne imaging (PHI). The preamplifier exhibits a noise level of 7 nV/Hz1/2 and a bandwidth from DC to 12 MHz sufficient for PHI experiments. Simulations of the preamplifier bandwidth and noise agree with the observed experimental characterization and performance in our home-built PHI system. The observed noise is close to the inherent limitations of the SR844 lock-in amplifier used. The results indicate that the preamplifier is also useful for any other single frequency pump-probe detection technique, such as stimulated Raman scattering.
Structural instability and dynamic emission fluctuations in zinc oxide random lasers
Authors: Peterson Zachariah , Word R. C. , Könenkamp R.
Published: August 2018

We report experimental results on the structural stability of optically pumped zinc oxide random lasers. We find that the lasing threshold is not entirely stable and depends on the accumulated light exposure received in pulsed optical pumping. We show that exposure levels below ∼1.5 kJ/cm2 improve the lasing efficiency and lower the lasing threshold. Beyond that value, however, lasing efficiency and threshold begin to degrade. Electron microscopy shows that the degradation is accompanied by morphological changes characteristic of melting. These changes become visible at an exposure of ∼0.7 kJ/cm2. We suggest that the melting is initially localized within nanometer areas and that the initial improvement is due to defect annealing. For exposures larger than 1.5 kJ/cm2, the melting zones connect, leading to deterioration. The findings apply to coherent and incoherent lasing. If stable output from ZnO random lasers is desired, lower lasing thresholds or higher damage thresholds are needed.
Advanced neutral alkali beam diagnostics for applications in fusion research (invited)
Authors: Zoletnik S. , Anda G. , Aradi M. , Asztalos O. , Bató S. , Bencze A. , Berta M. , Demeter G. , Dunai D. , Hacek P. , Hegedűs S. , Hu G. H. , Krizsanóczi T. , Lampert M. , Nagy D. , Németh J. , Otte M. , Petravich G. , Pokol G. I. , Réfy D. , Tál B. , Vécsei M. ,   W7-X Team
Published: August 2018

Diagnosing the density profile at the edge of high temperature fusion plasmas by an accelerated lithium beam is a known technique since decades. By knowledge of the relevant atomic physics rate coefficients, the plasma electron density profile can be calculated from the relatively calibrated light profile along the beam. Several additional possibilities have already been demonstrated: Charge Exchange Resonance Spectroscopy (CXRS) for ion temperature/flow and Zeeman polarimetry for edge plasma current; therefore the Li-beam diagnostic offers a wealth of information at the plasma edge. The weaknesses of the method are the relatively faint light signal, background light, and technical difficulties of the beam injector which usually seriously limit the applicability. In this talk, we present systematic developments in alkali-beam diagnostics (Li, Na) for the injector and the observation system and detectors which resulted in strongly increased capabilities. Advanced systems have been built, and microsecond scale density profile, turbulence, and zonal flow measurement have been demonstrated. A novel edge current measurement technique has also been designed, and components have been tested with potential microsecond-scale time resolution. Additional possibilities of these advanced systems for spectral measurements (CXRS and various Zeeman schemes) are also discussed.