bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of a transverse crack in a nonlinear rotor using non-stationary response
Authors: Wang Xiaofeng , Liu Jun , Ge Weimin
Published: November 2017

To accurately detect an early transverse crack in the rotating machinery caused by fatigue or creep, various kinds of diagnosis systems utilizing the steady-state responses of a cracked rotor were developed. The paper focuses on the non-stationary response of a rotor system such as the startup, the shutdown or the variable running speeds of a rotating machinery to detect a transverse crack and to overcome the defects of the diagnosis system utilizing steady-state responses. Non-stationary characteristics during passages through the major resonance and various kinds of resonances are studied numerically and experimentally. The results demonstrate that the changes of vibration characteristics in a non-stationary response can detect a crack in a wide rational speed range and also prevent the dangerous operation for detecting a crack.
Effect of vibration in the treatment of children with spastic diplegic cerebral palsy
Authors: Dudoniene Vilma , Lendraitiene Egle , Pozeriene Jurate
Published: November 2017

Cerebral palsy is one of the leading causes of movement and posture disorders. Recently, Vibration, as a treatment method in clinical practice has been used as a complementary approach. The aim of this intervention was to determine the effect of vibration in addition to conventional therapy on spasticity, range of motion and gross motor functions in children with cerebral palsy. A total of 20 children with spastic diplegic cerebral palsy (7-10 years old) were randomly divided into two equal groups (conventional therapy – Control group, and conventional therapy plus Vibration – Vibration group), and participated in a 3-week physiotherapy program. The same exercise program was prescribed for children of both groups; frequency of intervention ‒ five times a week, one session lasted for 45 min. Children in the vibration group apart from conventional therapy also received treatment on a special vibration equipment set at 15 Hz frequency. Ashwort scale was used to assess spasticity, goniometry – range of motion, and Gross Motor Function Measure (GMFM) 88 domain – to assess standing (D) and mobility (E – walking, jumping, and running) functions. Both interventions significantly increased range of motion, decreased spasticity in legs and improved standing and mobility functions (p< 0.05). No statistical differences were found between the two groups after interventions.
Influence of asymmetric structure parameters on rolling mill stability
Authors: Huang Jinlei , Zang Yong , Gao Zhiying , Zeng Lingqiang
Published: November 2017

Considering the asymmetric structure of a rolling mill system, a chatter model is established by coupling a rolling process model and structure model to describe the asymmetric vibration characteristics. According to this mathematical model, the critical rolling speed is determined by calculating eigenvalues of the characteristic matrix. Model correctness and validity are confirmed by an experimental observation of a 2030 cold rolling mill. On this basis, the effects of asymmetric structure parameters on the rolling mill stability are investigated with the help of the numerical approach. It is found that the influence of the asymmetric structure parameters on stability and critical conditions is significant. An optimal stiffness ratio and optimal mass ratio is determined, in order to ensure the best stability for the considered system. As the asymmetry in terms of the stiffness and mass becomes considerable, a modal conversion phenomenon occurs. This study serves as a contribution both for the mill vibration suppressing, and for mill optimization design.
Damage localization and quantification of composite beam structures using residual force and optimization
Authors: Behtani A. , Bouazzouni A. , Khatir S. , Tiachacht S. , Zhou Y.-L. , Abdel Wahab M.
Published: November 2017

Structural Health Monitoring (SHM) and impact monitoring of composite structures have become important research topics in the recent year. In this research, a non-destructive vibration-based damage detection method is formulated using Genetic Algorithm (GA) and compared with classical method. The robustness and reliability of the capability to locate and to estimate the severity of damage, based on changes in dynamic characteristics of a structure, is investigated. The objective function for the damage identification problem is established by using the residual force method (FRM). Numerical experiments using finite element analysis are performed on composite beams with different damage scenarios in order to clarify the validity of the developed technique. The comparison between estimated and real damage illustrates the efficiency of the algorithm in damage detection. The results show that the present approach is correct and efficient for detecting structural local damages in composite beam structures.
Vibration signal modeling of a localized defective rolling bearing under unbalanced force excitations
Authors: Fan Jun , Cui Wei , Han Qinkai
Published: November 2017

Vibration signal modeling of a localized defective rolling bearing under unbalanced force excitations is carried out in this paper. A mass-spring-damping system with eight degrees of freedom is derived to consider the transverse vibrations and high frequency resonances of the rotor and bearing pedestals. External excitations come from the unbalanced mass and self-weight of the rotor. Due to the Hertz contact and bearing clearance, the dynamic model is coupled by the nonlinear stiffness. The inner/outer race defects are localized and modeled by additional contact deformations. The Runge-Kutta method is utilized to solve the nonlinear coupled differential equations and vibration signals with and without defects are obtained. Through envelope analysis, the fault characteristic frequencies of inner/outer raceway defects with and without unbalanced force excitations are presented. Detailed comparisons show that the unbalanced force excitations have signiﬁcant inﬂuence on the fault characteristic frequencies. Finally, dynamic tests on a typical rotor-bearing system are conducted to verify the theoretical results.
Prediction of dynamic characteristics of a pantograph-catenary system using the displacement compatibility
Authors: Chen Guo , Yang Yiren , Yang Yang
Published: November 2017

Using the equation of displacement compatibility, a novel method for describing the contact between pantograph and catenary is proposed in this paper. Then an interaction catenary-pantograph system capable of describing vertical vibration is established. Taking into account the frictional characteristic between pantograph and catenary, the Coulomb model is applied. Based on the continuum mechanics, the partial differential equations of the coupling system are set up. For facilitating numerical simulation, the dynamic equations are further discretized by the Galerkin method, in which the modes of the complicated system are obtained by the finite element method. Therefore, the ordinary differential equations of the coupling system are numerically solved and the corresponding dynamic behaviors at different running speeds are analyzed in terms of waveform. Moreover, the effects of the frictional characteristic on the contact force between pantograph and catenary are discussed in detail. By comparing the results with European standard EN50318, the novel contact method is proved to be valid and accurate.
Relating structural damage to modal frequencies shift using low cost LQG-FEA approach and minimal feedback measurements
Authors: Al Ghailani Latifa , El-Sinawi Ameen
Published: November 2017

Vibration signature of flexible structures can be used as a tool to monitor the structural health and predict failure. This work presents a practical low cost technique for predicting vibration signature of a mechanical structure and relates it to its structural health. The technique utilizes a model constructed from Modal frequencies and Eigen vectors obtained via finite element analysis (FEA) of the structure. Linear Quadratic Gaussian (LQG) servo controller of the acceleration output of the model is utilized to minimize error between actual acceleration measurements and its estimates. The LQG controller requires minimal feedback measurements from the physical system and can provide acceleration estimates at any location on the structure. Thus, it is adaptable to structures that are complex and/or have limited accessible measurements points. Anytime during operation, a shift in estimated Modal frequencies of the structure is shown to have a strong relationship with variation in structural parameters, (i.e. structural damage). Therefore, the presented technique is unique for three reasons, (a) it uses estimates, rather than actual measurements to identify structural damage, (b) requires minimal feedback measurements from the structure and (c) uses an effective low-cost reduced order model to achieve (a) and (b). The proposed technique is utilized on a pipeline structure and is evaluated both numerically and experimentally as a proof of concept. Research outcomes are presented and discussed.
In-plane vibration modal analysis of heavy-loaded radial tire with a larger flat ratio
Authors: Liu Zhihao , Gao Qinhe
Published: November 2017

Experimental modal analysis, dynamic modeling and parameter identification is employed to investigate the in-plane vibration modal characteristic of a heavy-loaded radial tire with a larger flat ratio. In-plane vibration characteristic of heavy-loaded radial tire is modeled as flexible beam on modified elastic foundation model and flexible tread and distributed sidewall are respectively modeled as the Euler beam and distributed mass element with sectional stiffness. Analytic relationship between the modal resonant frequency and the structural parameters is solved and derived with modal expansion method. The in-plane coupling modal between the flexible tread and sidewall is investigated experimentally. The unknown structural parameters are identified by the genetic algorithm based on the experimental and analytical modal parameter. The higher order modal frequency is predicted with the identified structural parameters and the influence of structural parameters on the modal parameters is compared. Experimental and theoretical result shows that: the experimental modal analysis and theoretical modeling method with the coupling feature of flexible tread, distributed sidewall and rim can accurately characterize the in-plane vibration feature of heavy-loaded radial tire within the frequency band of 300 Hz, compared with the method which only considers the flexible feature of tread and is limited to 180 Hz.
Numerical study on aerodynamic characteristics of high-speed trains with considering thermal-flow coupling effects
Authors: Yang Ai Min , Li Yi Fan , Xing Hong Wei , Zhang Ling , Feng Li Jing , Li Yu Han , Cheng Fei Yu
Published: November 2017

In order to conduct in-depth researches on rationality of air conditioning system equipment of a high-speed train as well as its pipeline system design, working conditions of the air conditioning system and distribution of aerodynamic characteristics including pressure, velocity and temperature in high speed trains should be computed carefully at the design stage. Therefore, the finite volume method was used to solve a governing equation of computational fluid dynamics. The aerodynamic characteristics of pipelines of the air conditioning system and the complete high speed train were computed, so the indoor distribution of wind velocity, temperature and gas concentration (carbon oxide, carbon dioxide, nitrogen and so forth) was obtained. The flow field index and the thermal comfort index were used to evaluate the indoor thermal comfort degree. In this way, whether rationality of the air conditioning system design and indoor aerodynamic characteristic could satisfy requirements for design specifications can be analyzed. Results show that: Under winter or summer working conditions, wind velocity was relatively high at the passageway door, where the maximum wind velocity was more than 1 m/s and would make passengers uncomfortable. Air flow velocity outside comfortable regions was more than 0.05 m/s, satisfying UIC553 standards. Velocity distribution was basically the same indoors, where wind velocity was large at positions perpendicular to the air supply hole, and the maximum wind velocity was more than 1 m/s, but wind velocity was uniform in the passenger region, which was basically lower than 0.2 m/s and satisfied UIC553 standards. In summer and winter working conditions, distribution of pressure, velocity and temperature was not uniform, where the maximum temperature gradient was near the air inlet in the compartment. Air components in the compartment satisfied requirements for comfort. The most uncomfortable regions in the compartment were concentrated at the passageway. Air supply holes distributed symmetrically on the train roof caused high air flow intensity, high wind velocity, low temperature and high humidity at the passageway in the compartment, so the thermal comfort was low, and it is feasible to adjust the layout of air supply holes appropriately.
Engine power measurement without external load based on vibration signal
Authors: Zhang Shuai , Zeng Ruili
Published: November 2017

The vibration signals from engines contain information about the engine conditions. Engine power is an important parameter that indicates the state of an engine. In this manuscript, a method for measuring the engine power, using the vibration signals from the engine, is developed. In our proposed method, the power of the engine is measured based on the principle of no-load measurement. The discrete values of rotation speed are computed from the vibration signal, using wavelet transforms, the Hilbert envelope, and three autocorrelations. By comparing various curve-fitting and interpolation methods, an optimal method for curve fitting the discrete acceleration data is chosen, and the corresponding times of the starting speed and terminal speed are calculated using the analytical formulas of the fitted curve. Finally, the maximum engine power is obtained from the calibration tests. Experimental results show that the overall performance is good and that the maximum power measurement accuracy is 98.4 % after accurate calibration. This meets the requirements of the power measurement accuracy under the condition of no load.
Research on pressure fluctuation characteristics of a centrifugal pump with guide vane
Authors: Wang Yong , Luo Kaikai , Wang Kai , Liu Houlin , Li Yu , He Xianghui
Published: November 2017

In order to study the pressure pulsation characteristics of a centrifugal pump with a guide vane, a pump with specific speed ns= 190 was chosen as the research object. The numerical simulation was carried out using the standard k-ε turbulence model. The pressure pulsation characteristic was researched at a set monitoring point. The reliability of the numerical simulation was verified with experiment results. The pressure pulsation characteristic curves of each calculation domain were obtained by dimensionless data processing. The results elucidate that the rotor/stator interaction at the outlet of the impeller is the main source for the pressure pulsation. With increasing distance, the pressure pulsation gradually decreases; the pressure pulsation amplitude of the pressure surface is larger than the suction surface; the pressure pulsation in the flow channel of the guide vane remains the same; the pressure fluctuation near the outlet of the annular volute chamber is larger, and the pressure pulsation near the upstream of the flow channel is quite complicated. The pressure pulsation at the annular volute and axial symmetry is the same.
Active frequency tuning of the cantilever nanoresonator utilizing a phase transformation of NiTi thin film
Authors: Stachiv Ivo , Sittner Petr , Jeng Yeau Ren , Vokoun David
Published: November 2017

Due to their small sizes, compactness, low cost, high sensitivity, high resolution and extraordinary physical properties, nanoresonators have attracted a widespread attention from the scientific community. It is required that the nanoresonators can operate at desired but adjustable resonant frequencies. In this work, we present a novel active frequency tuning method utilizing a large change of the Young’s modulus (more than 50 %) and generated interlayer stress (up a few hundred of MPa) during a phase transformation of NiTi thin film deposited on an elastic substrate. We show that this tuning mechanism can allow one to achieve the extraordinary high fundamental resonant frequency tunability (~30 %). The impact of NiTi film thickness and dimensions on the first three consecutive resonant frequencies of the cantilever nanobeam is examined. In addition, developed theoretical model can be used as a simple guide for further design of novel tunable cantilever nanoresonators with thin films that cover only partially the entire cantilever length.
Dynamic behavior of reinforced concrete panels subjected to blast loading
Authors: Park Jong Yil , Kim Min Sook , Lee Young Hak
Published: November 2017

This paper presents experimental and analytical results for dynamic response of reinforced concrete one-way slab under blast loading. Steel frame with massive concrete foundation to minimize rigid movement was prepared for fixed-fixed boundary condition. Two 1500×2350×150 mm RC slabs were tested under surface bursts of 50 kg TNT and 100 kg TNT at standoff distance of 20 m. Types of measured data related to structural response includes strain of longitudinal reinforcement at mid-span, and longitudinal strain on unloaded side concrete at midspan. Incident pressures were measured at 15 m, 20 m, and 25 m to check if full detonation occurs. All measured data were compared with results of AUTODYN. Difference of peak reinforcement strains is 3 %, and one of concrete strains at surface of unloaded side is 11 %, showing that prepared numerical analysis can be used to estimate behavior of reinforced concrete one-way slab under explosion.
The evaluation of the sustainable transport system development with the scenario analyses procedure
Authors: Gołda Ilona Jacyna , Gołębiowski Piotr , Izdebski Mariusz , Kłodawski Michał , Jachimowski Roland , Szczepański Emilian
Published: November 2017

The problem of sustainable transport system development is currently very important and frequently analysed. It concerns promotion of such transport, which is efficient, cost effective and meets the expectations of the society. At the same time, such transport should minimize its negative impact on public health, environment, and economy or urban planning. This paper deals with selected aspects of developing sustainable transport systems and assessing them based on their negative impact on society (amount of pollution and noise emissions). A number of different scenarios for the sustainable transport system development were presented. In addition, a procedure for evaluating these scenarios was proposed (using appropriate evaluation criteria and indicators, including noise and pollutant emissions from road transport). The studies presented in this paper were carried out using the PTV Visum tool and transport models developed in it (e.g. EMITRANSYS or MTAW 2015).
The stability loss of the rotor-slide bearings system under random load variations
Authors: Pietkiewicz Paweł , Banaszek Sławomir , Żywica Grzegorz
Published: November 2017

The article presents how the system equipped with a rotor supported by slide bearings loses stability, operating under random load conditions. The computer simulations were applied for the analysis of the rotating machinery (using in-house developed codes). The MESWIR software is presented herein that can be used to assess dynamic performance of machines of this type. A special algorithm for the randomisation of loads was implemented and discussed in detail on the basis of a representative example. The rotor model was subjected to randomly-generated transverse forces during its operation. It exhibited unstable behaviour manifesting itself in the form of oil whirl or oil whip. The system operation was analysed both under constant and random load.
A novel index for damage detection of deck and dynamic behavior of horizontally curved bridges under moving load
Authors: Najafabadi Alireza Arabha , Daneshjoo Farhad , Bayat Mahmoud
Published: November 2017

The purpose of this paper is to evaluate the responses of horizontally curved bridges that are affected by vehicles load. The effect of vehicles dynamic loads on bridges is influenced by factors such as geometric characteristics of structures and moving loads specifications. To consider the effect of dynamic loads in design of bridges, static load increases with a coefficient which is called “impact factor” in Design Codes. In this paper, by examining the effect of curvature of deck and the speed of vehicles which are passing along the bridge on the dynamic response of bridge, set of new equations for DAF is presented. For this purpose, dynamic analysis is performed for seven bridges with different radius of curvature under the influence of AASHTO truck. In the case study models, it can be seen that the separation of impact factor into two different coefficients; support reaction and displacement responses make bridge design more economical and safer. Reduction of the curvature radius decreases dynamic amplification factor (both coefficients). To identify the possible damages of the examined bridges in the early stages of the advent a new index is presented. This index can predict the damages due to moving vehicles.
Energy recovery in high rate algal pond used for domestic wastewater treatment
Authors: Assemany Paula Peixoto , Calijuri Maria Lúcia , do Couto Eduardo de Aguiar , da Silva Fernanda Pereira , de Souza Mauro Henrique Batalha
Published: November 2017

High rate algal pond (HRAP) was evaluated according to its energy potential and productivity by two rates, net energy ratio (NER) and specific biomass productivity. All energy inputs were calculated according to one HRAP with pre-ultraviolet disinfection treating anaerobic domestic sewage. The outputs were calculated for two energetic pathways: lipid and biogas production for the raw biomass (RB) and biomass after lipid extraction. The non-polar lipid content in dry biomass was 7.6%, reaching a daily lipid productivity of 0.2 g/m2·day and the biogas production potential was 0.20 m3/kg solids. For the biomass after lipid extraction, the biogas production reached 2.6 m3/kg solids. NER values of 10−3 for the RB were similar for lipids and biogas routes. The specific biomass productivity was 0.7 mg/kJ. For the residual biomass, after lipid extraction, NER value was 10−2 for the integrated route (lipids + biogas) and the specific biomass productivity of the extracted biomass was 0.4 mg/kJ. The best energetic pathway was to integrate both lipids and biogas route.
La apropiación social del conocimiento un impulsor de la innovación: caso Asociación Horfrubella, Pereira- (Risaralda)
Authors: Díaz González Carolina
Published: November 2017

¿Cuáles son las estrategias de apropiación social del conocimiento evidenciadas en la Asociación Horfrubella que han impulsado la innovación en la producción de mora?; Este es el interrogante de la presente investigación, que toma como unidad de estudio la Asociación Horfrubella del municipio de Pereira; por ser un caso exitoso de escalonamiento agroindustrial y apropiación de tecnología de punta en el departamento de Risaralda. Para lograr el objetivo se realizó la identificación de la innovación en la producción de mora por los agricultores vinculados a Horfrubella; se utilizaron para ello herramientas diseñadas por la Red RAET de varias universidades (de Medellín, Jorge Tadeo Lozano, de los llanos y de Córdoba) y Colciencias en el libro: “Medición de la innovación agropecuaria en Colombia”, como las “encuestas de desarrollo e innovación tecnológica “(Eniagro)” y la matriz de innovación (MI). Dichas herramientas fueron aplicadas a diecisiete productores de mora de la asociación. Posteriormente, con el fin de identificar las estrategias de apropiación social del conocimiento que apalancaron los procesos de innovación en la asociación Horfrubella, se realizaron entrevistas a los productores y un taller siguiendo la metodología ZOPP (planificación de proyectos orientada por objetivos). Los resultados obtenidos evidencian las estrategias que implementó esta asociación de productores para generar innovación con el fin de crear valor agregado en procesos agroindustriales, y así llegar a garantizar canales de comercialización consolidados que han mejorado la calidad de vida de los asociados y han ampliado las oportunidades laborales de los mismos.
The effects of situational factors on the choice of the mechanical engineering expertise program in Vocational High Schools
Authors: Rahdiyanta Dwi
Published: November 2017

The objective of this study was to determine the effects of the family environment, the previous school environment, the social environment, and the students’ attitude on the choice of the mechanical engineering expertise program in Vocational High Schools (VHSs) by the graduates of Junior High Schools. This was a correlational study which was ex post facto in nature. The study population totaled 1095 students. The sample, consisting of 300 students, was selected using the proportional random sampling technique by means of the Krejcie and Morgan formula. The data were collected through inventories, observation sheets, and documents. The content validity was assessed through expert judgment. The construct validity was assessed using the factor analysis and the reliability using the Cronbach’s Alpha formula. The data were analyzed using the descriptive analysis, regression analysis, and path analysis at a significance level of 0.05. The results showed that, there were significant effects of the family environment, the previous school environment, the social environment, and attitude in the choice of mechanical engineering expertise program in VHSs by the graduates of Junior High Schools
The effect of silent short movie on EFL writing achievement of Vocational High School students
Authors: Kartika Rahmani Ayu Rinda , Susilo S. , Natsir Muhammad
Published: November 2017

The purpose of the study was to investigate whether or not there is a significant effect of silent short movie on EFL writing achievement of the vocational high school students. This study was quasi-experimental using a nonrandomized control group, pretest-posttest design. There were 61 students who were selected randomly from the 10 classes of tenth-graders of the 6th State Vocational School in Samarinda. The instruments used in the study was writing test. The result revealed that the vocational high school tenth grade students who were taught by silent short movie (M = 8.01, SD = .32) got significantly different achievement in EFL writing than did the vocational high school tenth grade students who were not taught by silent short, t(58) = -2.22, p = .030. This result suggests that the writing aspects which the students significantly outperformed were text organization, sentence formation, grammar, vocabulary, mechanics, and tidiness.
Factors affecting junior high school students’ interest in continuing to Vocational High School in Magelang District
Authors: Sari Dian Purnama , Munadi Sudji
Published: November 2017

This research aimed to reveal the effect of junior high school (SMP) students’ self-knowledge, academic achievement, counseling and guidance service, school (SMK) image to their interest in continuing their education to vocational high school (SMK) in Magelang District. The population of the research was all of grade IX SMP students, with 387 students as samples. The data were collected using questionnaires and documentation and were analyzed using descriptive and regression analysis. The result of this study shows that: (1) the interest of SMP students’ to continue their study to SMK is very high; (2) there is a positive and significant contribution of students’ self-knowledge, academic achievement, counseling and guidance service, school (SMK) image; to SMP students’ interest in continuing their study to SMK. The r2 values are 0.338; 0.063, 0.226, and 0.155, respectively; and (3) the four variables collectively have a positive and significant contribution to the interest in continuing the study to SMK in Magelang District with an r2 value of 0.440.
The implementation of integrated learning for developing the entrepreneurship readiness for the students of vocational high school majoring in architecture engineering
Authors: Hariyanto V. Lilik , Usman Husaini , Pardjono P.
Published: November 2017

The objective of the research was to: (1) find the level of integrated learning effectiveness between the entrepreneurship subjects and the stone and concrete practical subject from the perspective of the teachers and the students; (2) to find the level of integrated learning implementation between the entrepreneurship subject and the stone and concrete practical subject; (3) to find the level of teacher and student activities within the integrated learning between the entrepreneurship subject and the stone and concrete practical subject; and (4) to find the level of student readiness within the integrated learning between the entrepreneurship subject and the stone and concrete practical subject. The researchers implemented the Research and Development approach with an orientation toward the product development. The research period in the form of learning implementation within the classroom was from January to February 2013. The research site was in 2 Pengasih State Vocational High School Kulonprogo. The research subjects were the students of XI Grade Stone and Concrete Construction Engineering, 2 Pengasih State Vocational High School, Kulonprogo. The research procedures were divided into two stages namely: (1) pre-integrated learning implementation; and (2) integrated learning implementation. The research data included: (1) the effectiveness of integrated learning from the perspective of the teachers and the students; (2) the implementation of integrated learning; (3) the level of activeness that the teachers and the students exposed; and (4) the readiness of the students for performing entrepreneurship based on the achievement of learning competences in the domain of knowledge, attitude and skill. The data analysis was performed in a descriptive-qualitative manner by providing logical narratives  according to the research objectives. The results of the research were as follows: (1) the implementation of integrated learning, from the perspective of both the teachers and the students, had been in the category of effective to very effective; (2) the implementation of integrated learning had been in the category of good to very good; (3) the teachers and the students had been in the category of active to very active; and (4) the students had been in the category of ready for performing the entrepreneurship with the achievement of learning scores for more than the already determined passing grade.
The Concept and Practice of Critical Thinking in EFL Classes in Benin: Prospects and Challenges—Ministry of Higher Education and Scientific Research, Republic of Benin
Authors: Gbènakpon Sekoubaou, Abel,
Published: November 2017

Critical Thinking, formerly viewed as a western concept is now taught to learners worldwide as an important skill in education. This study deals with the necessity of incorporating Critical Thinking teaching in EFL classes in Beninese secondary schools through pointing out its advantages and current challenges to implementation. To collect relevant data for the research, three instruments were used: The Cornell Critical Thinking Test Level X, questionnaire and class observation. The target population has consisted of one hundred and fifty high school learners and sixty EFL teachers. The learners were split into two groups: the control group and the experimental one. Both groups took the critical thinking test twice, as pre- and post- tests. The results of the test and answers provided by teachers have revealed that teachers do not teach critical thinking skills to their learners. Trying to understand the root cause of this situation, the researcher has found that Beninese EFL teachers are not trained to teach and assess critical thinking skills.
Fiabilidad y validez de la Escala del Contínuum de Salud Mental (MHC–SF) en el contexto ecuatoriano
Authors: Peña Contreras Eva Karina , Lima Castro Sandra Eugenia , Bueno Pacheco Gladys Alexandra , Aguilar Sizer Mónica Elisa , Keyes Lee Corey , Arias Medina William Paúl
Published: November 2017

El presente estudio tiene como objetivo estudiar la estructura factorial, fiabilidad y validez del Contínuum de Salud Mental (MHC–SF) de Keyes (2009) en el contexto ecuatoriano. La escala fue aplicada a dos muestras, una de 100 personas que funcionó como piloto y otra de 550 personas residentes en la ciudad de Cuenca- Ecuador, a quienes también se aplicó una adaptación del Perfil PERMA de Butler y Kern (2016) para comprobar la validez convergente y discriminante. Se observó que la aplicación en esta población presenta adecuados niveles de ajuste y alta consistencia interna (α= .91) y un ajuste general adecuado de la estructura de tres factores: bienestar psicológico, bienestar social, bienestar emocional propuestos por el autor, dando valores de RMSEA= .045, CFI= .996, χ2(52)= 109.048 (p= .000), GFI= .997 y TLI= 0.993. El modelo bifactorial presenta valores de RMSEA= .042, CFI= .996, χ2 (52)= 103.040 (p= .000), GFI= .997, TLI= 0.993. Se concluye que la versión en español de MHC-SF (Keyes, 2009) y la versión bifactorial son herramientas apropiadas para medir la salud mental en el contexto ecuatoriano.
El problema del entendimiento en el lenguaje y la comunicación: Reflexiones desde un enfoque biofenomenológico
Authors: Romeu Vivian
Published: November 2017

En este trabajo se hace una reflexión en torno al papel del lenguaje en la comunicación a partir del entendimiento. Se busca comprender al lenguaje desde su estatuto onto-epistemológico y desde ahí, posicionar un cuestionamiento sobre su naturaleza intersubjetiva para objetar también a la comunicación entendida desde esta premisa. Se toman como referencia las perspectivas teóricas de la fenomenología, la biosemiótica, la neurobiología y la biología evolutiva, y se concluye que hay dos tipos de lenguaje: el social y el individual o subjetivo, lo que posibilita pensar a la comunicación como comportamiento y acto expresivo desde una dimensión subjetiva y otra intersubjetiva desde donde se articula el entendimiento.
Association of demographic and behavioral characteristics on financial decision making
Authors: Shahid Sana , Ahmad Basheer , Badar Munib
Published: November 2017

Managerial Risk acceptance criteria are affected by several factors. The study focuses on demographic and behavioral factors that plays their role in altering their decision making process. Questionnaires were distributed for collecting response of different professionals holding managerial positions encompassing Demographic Factors i.e. gender, age, marital Status and education, Behavioral factors i.e. Excessive Optimism, Over Confidence and Emotional Intelligence on risk perception. Reliability of the questionnaire is assessed through Cron Bach Alpha and to evaluate technical aspects of all variables, Linear regression and General Linear Univariate model are used. It is found that the variables including both, behavioral and demographic aspects are significantly associated with risk acceptance.
Performance of European banks: Crisis, corporate governance and convergence
Authors: Lazarides Themistokles
Published: November 2017

Financial performance as a phenomenon in the European banking sector is an issue of a wide debate. The paper is seeking to detect the variables that have an impact on performance. Ratios and stratification variables are used in panel data regressions and the time period of the study is from 2004 to 2013. The results show that performance (ROAA) is dependent on four categories of ratios (Asset quality, Capital ratios/risk and solvency ratios, Operations ratios, Liquidity ratios). Corporate governance system and the geographic location (political and macroeconomic factors) of the bank seem to effect significantly the factors that have an impact on performance.
Adaptive algorithm based on antenna arrays for radio communication systems
Authors: Fedosov Valentin , Legin Andrey , Lomakina Anna
Published: November 2017

Trends in the modern world increasingly lead to the growing popularity of
wireless technologies. This is possible due to the rapid development of
mobile communications, the Internet gaining high popularity, using wireless
networks at enterprises, offices, buildings, etc. It requires advanced
network technologies with high throughput capacity to meet the needs of
users. To date, a popular destination is the development of spatial signal
processing techniques allowing to increase spatial bandwidth of communication
channels. The most popular method is spatial coding MIMO to increase data
transmission speed which is carried out due to several spatial streams
emitted by several antennas. Another advantage of this technology is the
bandwidth increase to be achieved without expanding the specified frequency
range. Spatial coding methods are even more attractive due to a limited
frequency resource. Currently, there is an increasing use of wireless
communications (for example, WiFi and WiMAX) in information transmission
networks. One of the main problems of evolving wireless systems is the need
to increase bandwidth and improve the quality of service (reducing the error
probability). Bandwidth can be increased by expanding the bandwidth or
increasing the radiated power. Nevertheless, the application of these methods
has some drawbacks, due to the requirements of biological protection and
electromagnetic compatibility, the increase of power and the expansion of the
frequency band is limited. This problem is especially relevant in mobile
(cellular) communication systems and wireless networks operating in difficult
signal propagation conditions. One of the most effective ways to solve this
problem is to use adaptive antenna arrays with weakly correlated antenna
elements. Communication systems using such antennas are called MIMO systems
(Multiple Input Multiple Output multiple input - multiple outputs). At the
moment, existing MIMO-idea implementations do not always noticeably
accelerate traffic at short distances from the access point, but, they are
very effective at long distances. The MIMO principle allows reducing the
number of errors in radio data interchange (BER) without reducing the
transmission rate under conditions of multiple signal re-reflections. The
work aims at developing an adaptive space-time signal algorithm for a
wireless data transmission system designed to improve the efficiency of this
system, as well as to study the efficiency of the algorithm to minimizing the
error bit probability and maximizing the channel capacity.
Partition optimization for a random process realization to estimate its expected value
Authors: Marchuk Vladimir , Shrafel Igor , Chernyshov Dmitry , Minaev Alexander , Buryakov Stepan
Published: November 2017

The paper provides an analytical proof the optimal number of partitions of a
non-stationary random process realization, which is necessary for estimating
its expected value when using ?the estimation reproduction? method for signal
processing. This method allows to process signal with a limited volume of
priori information about the desired signal function and statistical
characteristics of the additive noise component.
Space monitoring of the earth on the presence of solid domestic wastes using a discrete orthogonal transforms
Authors: Kazaryan Maretta , Shahramanyan Mihail , Richter Andrey
Published: November 2017

The paper investigates multivariate Wavelet Haar?s series. To study on the
correctness is made by means of Tikhonov?s method. A theorem on stability
and uniform convergence of a regularized summable function of the
wavelet-Haar?s series functions in Lipschitz class with approximate
coefficients is proved. An experiment confirms the validity of Tikhonov?s
method using space monitoring of waste disposal facilities is conducted as
an example. Namely, the decoding of space images-images using N-dimensional
Haar?s wavelet transform is used.
Television images identification in the vision system basis on the mathematical apparatus of cubic normalized B-splines
Authors: Krutov Vladimir , Bezuglov Dmitriy , Voronin Viacheslav
Published: November 2017

The solution the task of television image identification is used in industry
when creating autonomous robots and systems of technical vision. A similar
problem also arises in the development of image analysis systems to function
under the influence of various interfering factors in complex observation
conditions complicated the registration process and existing when priori
information is absent, in background noise type. One of the most important
operators is the contour selection operator. Methods and algorithms of
processing information from image sensors must take into account the
different character of noise associated with images and signals registration.
The solution of the task of isolating contours, and in fact of digital
differentiation of two-dimensional signals registered against a different
character of background noise, is far from trivial. This is due to the fact
that such task is incorrect. In modern information systems, methods of
numerical differentiation or masks are usually used to solve the task of
isolating contours. The paper considers a new method of differentiating
measurement results against a noise background using the modern mathematical
apparatus of cubic smoothing B-splines. The new high-precision method of
digital differentiation of signals using splines is proposed for the first
time, without using standard numerical differentiation procedures, to
calculate the values of the derivatives with high accuracy. In fact, a method
has been developed for calculating the image gradient module using spline
differentiation. The method, as proved by experimental studies, and
computational experiments has higher noise immunity than algorithms based on
standard differentiation procedures using masks.
‘HIDDEN OBJECT MEDIA’ FOR TEACHING ENGLISH AT THIRD GRADE ELEMENTARY STUDENTS IN SD LABORATORIUM UNDIKSHA SINGARAJA
Authors: Sari I. A. P. P. G.
Published: November 2017

This research aimed to (1) analyze the use of ‘Hidden Object Media’ in teaching English for third-grade elementary students in SD Lab Undiksha Singaraja. The subject of this research was thirty seven of third grade students in SD Lab Undiksha Singaraja at even semester academic year 2016/2017. This research categorized as descriptive qualitative in the form of graphs and percentage. Some instruments were used to conduct this research. There was interview guide, observation sheet and questionnaire. There are four media that was trying out based on topic of animals and body parts. Each media consist of teacher’s guidelines, brief story, hidden object handout, and list of possible post activities. Based on the result of students’ interview and teacher’s questionnaire it was found that hidden object media were able to involve students in learning, able to motivate and help students learn new vocabularies. The percentage shows that more than 78% in every session students felt happy, more than 57% in every session students felt helpful and 100% students feel motivated and feel that the media were good for them to be used. Thus, this media was proper to use for teaching English for third grade students.
THE EFFECT OF BIG BOOK AS MEDIA ON STUDENTS’ READING COMPREHENSION AT FIFTH GRADE OF ELEMENTARY SCHOOL
Authors: Mahayanti N. W. S. , Artini L.P. , Nur Jannah I. A.
Published: November 2017

This study was aimed at investigating whether or not there was a significant effect of the implementation of Big Book as media on reading comprehension achievement of the fifth grade students. This study was conducted in SD Laboratorium Undiksha Singaraja in the form of an experimental research with post-Test only Control Group Design. The population was the fifth grade in which two classes were selected as the sample of the study. Then, the samples were decided as the experimental group and control group by using lottery. The experimental group was taught by using Big Book as media and the control group was taught by using conventional media. The data were analyzed by using t-test through SPSS 17.0. The result of the data analysis showed that students in experimental group performed better than the students in the control group. It was proven by the result of the descriptive statistics that showed the mean score of the experimental group was 85.51 while the mean score of the control group was 75.56. The result of the t-test also showed that the value of Sig (2-tailed) 0.000 was less than 0.05. It can be concluded that there was a significant difference of reading comprehension achievement between students treated with big book as media and those treated using conventional media at fifth grade of elementary school in SD Laboratorium Undiksha Singaraja.
STRUCTURAL INVESTIGATION OF SOME NATIVE BIODEGRADABLE PACKAGING MATERIALS
Authors: COZAR Onuc , CIOICA Nicolae , NAGY Elena Mihaela , COŢA Constantin , FECHETE Radu , FILIP Claudiu
Published: November 2017

The IR, Raman and NMR methods are used to investigate the structural effects of water and glycerol (plasticizers) on biodegradable packaging materials proceeding from native corn starch. The IR and Raman methods not give a clear response on the amorphous/crystalline content in the investigated starch samples because the origin of vibrational bands is in the same atomic groups of the major starch components (amylose, amylopectin). The nuclear magnetic relaxation data show that the amorphous/crystalline ratio depends not only by the amylose/amylopectin content but also of the mobility and the place of theirs polymer chain segments. The shapes of 13C CP/MAS NMR spectra show clearly the presence of A, B, V-types crystalline structures and also amorphous phase which prevails with the increasing of plasticizers content and also in the extruded starch samples. The composition having starch/glycerol/water 68/17/15 mass % ratio was found to have a dominant amorphous character and very similar features with a commercial specimen (USA) used for the package. It was also found that this best package is extremely degraded after just one day under water absorption.
COMPARATIVE STUDIES REGARDING THE USE OF RECYCLED PVC IN FINITE PRODUCTS
Authors: PETRI Zosin Sergiu , RISTOIU Dumitru , BELDEAN-GALEA Mihail Simion , MIHĂIESCU Radu
Published: November 2017

The PVC wastes generated by post-industrial and post-consume activity creates serious problems regarding their wastes management. In the last years, the concept of reusing these wastes in other finite products became very attractive due to some advantages such as: eliminate the problems of their storage, decrease the price of the products in which these wastes are enclosed, and protect the environment against pollution. This paper presents some comparative studies regarding the use of recycled PVC in finite products such as obtaining PVC multilayer pipes. The quality and performances of the new products were compared with products in which only virgin PVC is used. The results showed that the quality of the finite products which contained recycled PVC is comparable with those of virgin PVC. Thus rigidity, flexibility, dimensional variation and shock resistance are similar or even superior if we use recycled PVC as raw material. The conclusion is that recycled PVC can be successful reused for obtaining PVC multilayer pipes being suitable to use in a percentage of 30-50%. Moreover, the economical benefices of this method are considerable.