bluuebunny/crossref_metadata_2025 huggingface dataset:
OPTIMASI WAKTU FERMENTASI PRODUKSI BIOETANOL DARI DEDAK SORGHUM MANIS (Sorghum Bicolor L) MELALUI PROSES ENZIMATIS
Authors: Arif Abdullah Bin , Budiyanto Agus . , Diyono Wahyu . , Richana Nur .
Published: February 2018

Salah satu energi baru terbarukan (EBT) yang potensial untuk dikembangkan adalah bioetanol. Bioetanol merupakan salah satu EBT yang banyak dipertimbangkan sebagai bahan bakar pengganti minyak bumi. Sorgum merupakan tanaman yang dapat dijadikan sebagai bahan baku untuk produksi bioetanol. Tujuan penelitian ini yaitu untuk memperoleh konsentrasi enzim terbaik saat hidrolisis dan waktu fermentasi yang optimum pada produksi bioetanol dari dedak sorgum manis. Penelitian dilaksanakan di Laboratorium Balai Besar Penelitian dan Pengembangan Pascapanen Pertanian, Bogor pada bulan Januari-Mei 2016. Bahan-bahan yang digunakan meliputi dedak sorgum manis, enzim amilase, enzim glukoamilase dan Saccharomyces cereviseae. Pada penelitian ini terdapat tiga tahapan kegiatan, yang meliputi: Karakterisasi bahan baku, optimasi hidrolisis enzimatis pada produksi gula dari dedak sorgum, optimasi pengaruh perlakuan penambahan konsentrasi enzim (α-amilase dan glukoamilase) dan lama fermentasi pada produksi bioetanol dari dedak sorgum. Hasil penelitian menunjukkan bahwa dedak sorgum manis dapat digunakan sebagai bahan baku pembuatan bioetanol dengan waktu fermentasi optimum selama 48 jam dengan penambahan konsentrasi enzim α-amilase : glukoamilase (0,5 : 1,5) ml/kg dengan hasil rendemen sebanyak 20,88%.
STUDI SIFAT FISIKOKIMIA DAN FUNGSIONAL PADI LOKAL (MAYANG PANDAN) PADA BERBAGAI TINGKAT DERAJAT SOSOH
Authors: Febriandi Erico , Widowati Sri , Sjarief Rizal
Published: February 2018

Mayang Pandan adalah padi merah lokal Bangka Belitung yang banyak dikonsumsi warga lokal, baik dalam bentuk pecah kulit ataupun disosoh. Namun hingga saat ini belum ada penelitian yang mengkaji sifat fisikokimia tersebut. Penelitian ini bertujuan untuk mengetahui sifat fisikokimia, sifat fungsional dan organoleptik. Rancangan penelitian yang digunakan adalah Rancangan acak lengkap dengan 4 perlakuan derajat sosoh (DS) (0% sebagai kontrol, 80, 90, dan 100%). Dari hasil penelitian diketahui bahwa DS 0 % memiliki nilai kadar lemak, protein, karbohidrat, antosianin, Vitamin B1, dan daya cerna pati secara berturut-turut yaitu 3,69 %, 9,84 %, 84,87%, 364,20 ppm, 0,40 mg/100g, dan 45,05%. Untuk DS yang memiliki nilai gizi yang paling mendekati DS 0% adalah DS 80 %, dengan nilai kadar lemak, protein, karbohidrat, antosianin, Vitamin B1, dan daya cerna pati secara berturut-turut yaitu 1,99%, 9,48 %, 87,64%, 102,19 ppm, 0,20 mg/100g, dan 47,50%. Hasil uji organoleptik Mayang Pandan dengan derajat sosoh 80 % memiliki rasa yang paling disukai panelis. Hal ini menunjukkan Mayang Pandan berpotensi sebagai padi lokal unggul bila dibandingkan dengan Aek Sibundong.
“Photonics explorer kit”, una nueva herramienta para la enseñanza experimental básica de la fotónica
Authors: Ruiz-Salmerón Luis
Published: February 2018

La Unión Europea estableció la fotónica como una de las 5 tecnologías facilitadoras clave (Key EnablingTechnologies, KET). En este año 2015, declarado por las Naciones Unidas como Año Internacional dela Luz, debemos incrementar su divulgación en los centros educativos. Dentro de este esfuerzo, debemosincluir el de introducir a los jóvenes, especialmente del sexo femenino, en el mundo científicotecnológico.El objetivo de este artículo de revisión es describir el estado del arte del "Photonics explorerkit" (PEK) así como sentar las bases para la búsqueda de distintos caminos que lleven al desarrollo desus potencialidades. Más allá de la educación secundaria, para lo que fue diseñado originalmente, ampliaremossu campo de acción a la Universidad. Se realizó una búsqueda de diversas bases de datospara describir lo ya hecho, su desarrollo y aplicaciones; así como composición y posibles kits alternativos.Existe poca información publicada, casi nula si buscamos en castellano y aplicada al sistema educativoespañol. Encontramos varios kits similares. Como ya en el proyecto piloto PEK se añadieronnuevos desarrollos basados en sugerencias de profesores y alumnos; buscamos poder desarrollarloaún más, y expandirlo a otros ámbitos educativos.
Robot navigation in dynamic environments using global-appearance descriptors. State of the art
Authors: Berenguer Fernández Yerai
Published: February 2018

Map building and localization are two impor- tant abilities that autonomous mobile robots must develop. This way, much research has been carried out on these topics, and researchers have proposed many approaches to address these problems. This work presents a state of the art report on map building and localization using global appearance descriptors. In this approach, robots capture visual information from the environment and obtain, usually by means of a transformation, a global appearance descriptor for each image. Using these descriptors, the robot is able to estimate its location in a map previously built, which is also composed of a set of global appearance descriptors. Several previous investigations that have led to the approach of this research are summarized in this paper, such as researches that compare several methods of creating global appearance descriptors. In these works we observe how the continuous optimization of the algorithms has lead to better estimations of the robot position within the environment. Finally a number of future directions in which researches are currently working are listed.
Citoesqueleto y neurotransmisión. Bases moleculares e interacciones proteicas del transporte y fusión vesicular en un modelo neuroendocrino
Authors: Giménez Molina Yolanda
Published: February 2018

El estudio de la red citoesqueletal y su función en el proceso de liberación de neurotransmisores y hormonas por exocitosis conocido con el término de neurosecreción es fundamental para entender como realizan su función los sistemas nervioso y endocrino. Son muchas las publicaciones que han venido contribuyendo a la elucidación de las bases moleculares y etapas del proceso en la célula cromafín, un excelente modelo neuroendocrino, utilizando una estrategia multidisciplinar que combina herramientas moleculares bioquímicas y de biología molecular, con un análisis biofísico de alta resolución temporal de la secreción y de imagen por microscopia confocal dinámica, FRET y TIRFM de los fenómenos de transporte vesicular e interacción proteica. La línea de investigación propuesta como cuerpo central de esta futura tesis doctoral pretende profundizar en el estudio de la configuración estructural citoesqueletal y su dinámica así como de proteínas participantes e interacciones entre estas, que gobiernan las etapas de transporte, atraque vesicular y de fusión de membranas constituyentes del proceso exocitótico. Dicho conocimiento resultará esencial para el desarrollo de terapias específicas para enfermedades tales como el Parkinson o el Alzheimer cuya etiología tiene base en defectos de la neurotransmisión.
Acoso escolar: características, factores de riesgo y consecuencias
Authors: Cañas-Pardo Elizabeth
Published: February 2018

La repercusión que el acoso escolar está teniendo actualmente sobre la conciencia social se debe a que este tipo de violencia escolar involucra y afecta a toda la sociedad y no sólo a la víctima y al agresor como se pensaba hasta ahora. Motivado por esta preocupación, el objetivo de este estudio se centró en aportar una definición amplia del concepto de acoso escolar, así como, proporcionar datos significativos acerca de la prevalencia, de los factores de riesgo y las consecuencias del acoso escolar. Para ello se realizó una revisión bibliográfica de fuentes nacionales e internacionales, teniendo en cuenta las bases de datos Psicodoc, Psycarticles, Psicinfo, Dialnet y Scopus y seleccionando aquellos estudios que se ajustaban con el objetivo de la presente investigación. Los hallazgos de las 36 investigaciones seleccionadas nos permiten afirmar que existen características individuales y familiares de cada uno de los niños que están directamente relacionados con la mayor o menor incidencia de las situaciones de acoso escolar. Junto a ellos debe tenerse en cuenta la influencia de aspectos escolares, sociales y culturales. El conjunto de todos ellos podría determinar la probabilidad de que ese niño en particular se convierta en acosador o víctima, siendo crucial para ese riesgo el contexto inmediato.
Nueva aproximación para rehabilitar la marcha basada en la combinación de neurotecnologías y exoesqueletos
Authors: Rodríguez-Ugarte Marisol
Published: February 2018

Cada día se está más cerca de conseguir que personas que han sufrido un accidente cerebrovascular (ACV) vuelvan a caminar con menos dificultad. Para mejorar la rehabilitación y el incremento de la plasticidad cerebral (LTP) en personas que han sufrido un ACV, nuestro grupo propone la combinación de técnicas de neuroestimulación (tDCS/tACS), interfaces cerebro-máquina (BMIs) y exoesqueletos. La neuroestimulación tDCS/tACS es una técnica relativamente nueva que está siendo ampliamente investigada a día de hoy para comprobar si produce plasticidad cerebral. Aunque se ha investigado mucho las BMI en las últimas décadas, lograr una BMI precisa y efectiva es algo arduo y tedioso en el campo de la rehabilitación o control de extremidades (e.g. exoesqueletos). Los exoesqueletos son órtesis colocadas en alguna extremidad del cuerpo que permiten asistir durante el movimiento. Este artículo describe las tecnologías que se van a usar para mejorar las terapias de rehabilitación actuales. Además, se explican las diferentes fases del proyecto ASSOCIATE para lograr nuestro objetivo.
Genome-wide Identification and Expression Pattern Analysis of Zinc-finger Homeodomain Transcription Factors in Tomato under Abiotic Stress
Authors: Hu Jingkang , Gao Yingmei , Zhao Tingting , Li Jingfu , Yao Meini , Xu Xiangyang
Published: February 2018

Members of the zinc-finger homeodomain (ZF-HD) family play a key role in the control of plant growth and development, which are involved in plant responses to stress. Although many functional studies of this gene family have been performed in different plants, the features of this family in tomato (Solanum lycopersicum) remain unknown. In this study, we identified 22 ZF-HD genes in the tomato genome and classified them into seven groups located on six chromosomes. Expression of 15 ZF-HD genes in tomato was studied in different tissues to identify their putative functions in many aspects of plant growth and development. Based on previous phylogenetic analyses in arabidopsis (Arabidopsis thaliana), our results showed that some tomato SL-ZH (S. lycopersicum zinc-finger homeodomain) genes cluster into the same neighbor-joining (NJ) branch as arabidopsis, indicating that these genes may share similar structures and functions in these plants. Gene expression analysis demonstrated that the tomato ZF-HD gene may be involved in abiotic stress responses, the SL-ZH13 gene in cold stress and the SL-ZH15 gene in drought stress; almost all tomato ZF-HD genes were responsive to salt stress, except for SL-ZH7, -ZH8, and -ZH22. However, the structures and functions of unknown groups require further research. In conclusion, this study identified tomato ZF-HD genes and analyzed their gene structures, subfamily distribution, and expression characteristics. These experiments combined with previous research findings reveal significant information and insight for future studies on the agronomic features and stress resistance in tomato.
Differential Responses of Amino Acids and Soluble Proteins to Heat Stress Associated with Genetic Variations in Heat Tolerance for Hard Fescue
Authors: Wang Jinyu , Yuan Bo , Xu Yi , Huang Bingru
Published: February 2018

Amino acid and protein metabolism are interrelated and both play important roles in plant adaptation to heat stress. The objective of this study was to identify amino acids and soluble proteins associated with genetic variation in heat tolerance of hard fescue (Festuca trachyphylla). According to a previous screening experiment, the hard fescue cultivars Reliant IV and Predator were selected as heat-tolerant and heat-sensitive cultivars, respectively. Plants of these two hard fescue cultivars were exposed to heat stress at 38/33 °C (day/night) or optimal temperature at 21/18 °C in growth chambers. Each cultivar had four replications under each temperature, and the experimental design was a split-plot design, temperature as the main plots and cultivars as the subplots. Under heat stress, ‘Reliant IV’ exhibited higher turf quality (TQ) and greater membrane stability than ‘Predator’. In response to heat stress, total amino acid content increased, whereas total soluble protein content decreased in both cultivars. The greater accumulation of amino acids in ‘Reliant IV’ was contributed by the greater increase of proteins involved in the glycolysis and the tricarboxylic acid (TCA) cycle that provided carbon skeleton for amino acid synthesis. ‘Reliant IV’ leaves exhibited greater extent of increases in the content of six individual amino acids (histidine, glutamine, proline, threonine, aspartate, and tryptophan) than ‘Predator’ under heat stress. Several soluble proteins were upregulated in response to heat stress, to a greater extent in ‘Reliant IV’ than ‘Predator’, including the proteins involved in photosynthesis, protein folding, redox hemostasis, stress signaling, stress defense, cell organization, and metabolism. These differentially accumulated free amino acids and soluble proteins could be associated with the genetic variation in heat tolerance of hard fescue.
Relationship between Phloem Fiber and Trailing Habit, and Independent Inheritance of Growth Habit and Flower Form in Periwinkle
Authors: Lin Huan-Keng , Wei Tzu-Yao , Chen Chin-Mu , Yeh Der-Ming
Published: February 2018

Stem anatomy and modulus of elasticity (MOE) were compared between upright and trailing cultivars of periwinkle [Catharanthus roseus (G.) Don.]. The inheritance of growth habit and flower form was also studied. Internode cross sections revealed that phloem fiber was distributed at the inner cortex in upright cultivars but not in trailing cultivars. Except the youngest internode, the upright ‘Vitesse Pink’ had the highest MOE throughout the 1st–13th internodes above the cotyledon. The more trailing ‘Cora Cascade Strawberry’ had consistently lower MOE than a less trailing ‘Cora Cascade Polka Dot’. All F1 plants between upright and trailing cultivars were upright, and the F2 generation derived from self-pollinating F1 fit a 3 upright : 1 trailing segregation ratio. All F1 plants between upright/double-flower and trailing/single-flower exhibited upright and single-flowers, whereas plants in the F2 generation fitted a 9 upright/single-flower : 3 trailing/single-flower : 3 upright/double-flower : 1 trailing/double-flower ratio. New double-flowered periwinkle selections with trailing growth habit were successfully developed from the F2 population.
Genome-wide Identification and Expression Pattern Analysis of BRI1-EMS–suppressor Transcription Factors in Tomato under Abiotic Stresses
Authors: Gao Yingmei , Hu Jingkang , Zhao Tingting , Xu Xiangyang , Jiang Jingbin , Li Jingfu
Published: February 2018

BRI1-EMS-suppressor 1 (BES1) is a transcription factor (TF) that functions as a master regulator of brassinosteroid (BR)-regulated gene expression. Here, we provide a complete overview of Solanum lycopersicum BES1 (SLB) genes, including phylogeny, gene structure, protein motifs, chromosome locations and expression characteristics. Through bioinformatic analysis, we compared the sequences of SLB genes, arabidopsis (Arabidopsis thaliana) genes, and chinese cabbage (Brassica pekinensis) genes. All of the gene sequences were divided into three groups by cluster analysis. SLB genes were mapped to the eight tomato (S. lycopersicum) chromosomes. Bioinformatic analysis showed that SLB genes shares similarities with the proteins from other plants, though different species exhibit specific features. The expression patterns of SLB genes in various tissues and under different abiotic conditions were analyzed by quantitative reverse transcription polymerase chain reaction. SLB genes were found to be induced by multiple stresses, particularly salt stress, indicating that SLB genes may have important roles in the response to unfavorable environmental changes. This study provides insight into the evolution of SLB genes and may aid in the further functional identification of BES1 proteins and the response of tomato plants to different stresses.
REVITALIZING SOCIAL SANCTIONS OF CUSTOMARY LAW TO ERODE PERMISSIVISM TOWARD CORRUPT BEHAVIOR IN SOCIETY
Authors: Busroh Firman Freaddy
Published: February 2018

ABSTRACTCorruption is still common in Indonesia. The existence of permissive culture in Indonesian society has caused corruption to continue to flourish and difficult to eradicate. Many cases of corruption have been brought to trial, but it is still unable reduce the level of corruption. Permissive culture (or also known as permissivism) is still often encountered in everyday life, such as granting bribes for administration, from office to religious affairs, such as marriage. The development of this permissive culture is due to the advancement of the times and the increasing lifestyle of hedonism in society which result in the community being consumptive. Unwittingly, the permissive culture has permitted corrupt behavior to occur. Corruption is an act that cannot be justified in any aspect. Corruption is detrimental to the State's finances which has an impact on the waiver of public interest. In addition, corruption also has a negative impact on various fields. So, corruption is an unforgivable act. Therefore, it is necessary to revitalize social sanction in combating the culture of corruption. Indonesia, as a legal laboratory, has various kinds of customary law. Customary law in Indonesia has traditional religious characteristics that use religious and cultural approaches. Some areas in Indonesia that still uphold the value of religion and customs can be used as a foundation to eradicate permissivism of corrupt behavior. In religion and custom there are social sanctions that can cause the feelings of shame for the perpetrators of corruption. Such social sanctions include exclusion, expulsion from a territory, or even the removal of a customary title. The revitalization of social sanctions could be part of a strategy for eradicating corruption in Indonesia.
THE ROLE OF LOCAL WISDOM AS PART OF CORRUPTION ERADICATION STRATEGY
Authors: SETIADARMA LIM KURNIAWAN
Published: February 2018

ABSTRACT Corruption has been a pervasive problem plaguing our country for a long time. On the other hand, raising community awareness and enhancing public participation have been acknowledged as part of the corruption prevention and eradication strategy in Indonesia for many years, especially since the enactment of 1999 Corruption Law. Nonetheless, public participation in the country seems to keep decreasing throughout the years, leaving corruption alone eroding every sector of society. For this reason, it is important to realize that the success level of public participation is highly related to the existing beliefs and values of people that are expected to be participating – the local wisdom. The purpose of this paper is to evaluate the effectiveness of public participation in eradication of corruption, assess whether the local wisdom has been supporting the corruption eradication/prevention strategy, and finally conclude with a proposition to maximize the role of local wisdom in combatting corruption in Indonesia. To achieve that goal, delving into applicable laws, general principles of law, journals and books, cases and reports, as well as various surveys becomes very important to increase the knowledge and objectivity in thinking and analyzing. Two surveys were also conducted to Indonesian citizens with 328 respondents and 495 respondents, in order to see the real cultures and beliefs that are currently developing in Indonesian society. This research paper will reveal the current Indonesian local wisdom on the ground and its connection to the large strategy of corruption eradication at national level.
Republished Paper. Numerical study for single and multiple damage detection and localization in beam-like structures using BAT algorithm
Authors: Khatir Samir , Belaidi Idir , Serra Roger , Wahab Magd Abdel , Khatir Tawfiq
Published: February 2018

This paper presents a new damage detection and localization technique based on the changes in vibration parameters using BAT and Particle Swarm Optimization algorithm. The ﬁnite element method is used to apply damage at specific element(s) of the considered beams. The damage is represented by a reduction in Young’s modulus and the identification of damage is formulated as an optimization problem using objective function based on Modal Scale Factor and changes in natural frequencies. A procedure for detecting and locating damage of beam-like structures based on BAT algorithm is used. This approach presents a method that can be used to detect the single and multiple-damage positions and the rate of damage in structural elements with high accuracy after the first iteration. The results obtained using BAT algorithm are compared to those obtained using Particle Swarm Optimization Algorithm. By taking noise into account in the damage detection and localization problem, it is shown that our approach based on BAT algorithm can detect the damage locations with high accuracy.
Republished Paper. Rapid early damage detection using transmissibility with distance measure analysis under unknown excitation in long-term health monitoring
Authors: Zhou Yun-Lai , Abdel Wahab Magd
Published: February 2018

Accurate and efficient damage detection in long-term health monitoring for structures still encounters many difficulties due to the effect of environment. Furthermore, recorded big data requires efficient damage detection algorithm. In this study, an efficient and effective damage detection algorithm is proposed using transmissibility along with Mahalanobis distance and Hotelling T-square. A numerically simulated beam and an experimentally tested laboratory structure are used to validate the proposed algorithm. Results demonstrate good performance of the proposed technique in damage detection.
Republished Paper. Multiple damage detection and localization in beam-like and complex structures using co-ordinate modal assurance criterion combined with firefly and genetic algorithms
Authors: Khatir Abdelwahhab , Tehami Mohamed , Khatir Samir , Abdel Wahab Magd
Published: February 2018

Damage detection and localization in civil engineering constructions using dynamic analysis has become an important topic in recent years. This paper presents a methodology based on non-destructive detection, localization and quantification of multiple damages in simple and continuous beams, and a more complex structure, namely two-dimensional frame structure. The proposed methodology makes used of Firefly Algorithm and Genetic Algorithm as optimization tools and the Coordinate Modal Assurance Criterion as an objective function. The results show that the proposed combination of Coordinate Modal Assurance Criterion and Firefly Algorithm or Genetic Algorithm can be easily used to identify multiple local structural damages in complex structures. However, the convergence rate becomes slower for the case of multiple damages compared to the case of single damage. The effect of noise on the algorithm is further investigated. It is found that the proposed technique is able to detect the damage location and its severity with high accuracy in the presence of noise, although the convergence rate became slower than in the case when no noise is present. It is also found that the convergence rate of Firefly Algorithm is much faster than that of Genetic Algorithm.
Dynamic instability analysis of U-shaped electromechanical nano-sensor operated in vdW regime
Authors: Keivani Maryam , Ghahremani Esmaeil , Koochi Ali , Mokhtari Javad , Abadian Naeime , Abadyan Mohamadreza
Published: February 2018

U-shape nanoelectromechanical systems (NEMS) are potential for developing miniature sensors. While the electro-mechanical performance of conventional beam-type NEMS has been exclusively addressed in the literature, few works have considered this phenomenon in U-shaped systems. Herein, the static and dynamic pull-in instability of the U-shaped NEMS is investigated under the presence of vdW force. Based on the recently developed consistent couple stress theory (CCST), the size-dependent constitutive equation is derived. Two types of the beam cross-sections including rectangular and circular geometries are considered. The nonlinear equations are solved by employing Ray-leigh-Ritz solution method. The developed model is validated by comparison with the results presented in literature. The effect of various parameters on the static and dynamic pull-in parameters, phase plans and stability threshold of the system is discussed. The obtained results reveal that the vdW attraction decreases the pull-in voltage while the size dependency enhances the instability voltage. On the other hand, the presented model demonstrates that characteristics of the tip-plate can change the pull-in parameters significantly.
The effect of noise on the comfort of passengers inside the tramway and its impact on traffic congestion in the urban area
Authors: Khelf Mouloud , Boukebbab Salim
Published: February 2018

The tramway is a mean of transport which is used frequently in many cities around the world, because it improves the offer of public transport through its important capacity of transporting. This may ameliorate the state of road traffic by reducing the number of vehicles along the tram line. Despite these advantages, there are some problems related to users’ comfort like the noise caused during the operation. This study is focused on the human perception of the noise levels detected inside the tramway. The objective of this work is to identify and analyze the level of noise detected inside tramway, to know in which cabin and section the high noise is recorded, to find the causes and to show if the measured noise influences the comfort of passengers. For that, noise measurements are taken in all cabs and along the tram line. The results show that the levels of noise inside the seven cabins is different. The high noise is detected in the motorized cabins and in many sections, like the curves and also in other sections. The results show also that this noise affects negatively on the comfort of passengers. Finally, different solutions that can contribute to reduce effectively the noise to make the tram more comfortable and efficient to relieve traffic congestion in urban areas are presented.
Differential quadrature method (DQM) for studying initial imperfection effects and pre- and post-buckling vibration of plates
Authors: Makvandi Hesam , Moradi Shapour , Poorveis Davood , Heidari Shirazi Kourosh
Published: February 2018

The effects of initial geometric imperfection and pre- and post-buckling deformations on vibration of isotropic rectangular plates under uniaxial compressive in-plane load have been studied. The differential equations of plate motions, using the Mindlin theory and Von-Karman stress-strain relations for large deformations, were extracted. The solution of nonlinear differential equations was assumed as the summation of dynamic and static solutions. Due to a large static plate deflection as compared with its vibration amplitude, the differential equations were solved in two steps. First, the static equations were solved using the differential quadrature method and the arc-length strategy. Next, considering small vibration amplitude about the deformed shape and eliminating nonlinear terms, the natural frequencies were extracted using the differential quadrature method. The results for different initial geometric imperfection and different boundary conditions reflect the impact of the mentioned factors on the natural frequencies of plates.
Joint sparse representation based classification of rub-impact in rotating machinery with multiple acoustic emission sensors
Authors: Peng Wei , Li Jing , Liu Weidong , Shi Liping , Li Han
Published: February 2018

Acoustic emission (AE) technique has been widely used for the classification of rub-impact in rotating machinery due to its high sensitivity, wide frequency response range and dynamic detection property. However, it is still unsatisfied to effectively classify the rub-impact in rotating machinery under complicated environment using traditional classification method tailored to a single AE sensor. Recently, motivated by the theory of compressed sensing, a sparse representation based classification (SRC) method has been successfully used in many classification applications. Moreover, when dealing with multiple measurements the joint sparse representation based classification (JSRC) method could improve the classification accuracy with the aid of employing structural complementary information from each measurement. This paper investigates the use of multiple AE sensors for the classification of rub-impact in rotating machinery based on the JSRC method. First, the cepstral coefficients of each AE sensor are extracted as the features for the rub-impact classification. Then, the extracted cepstral features of all AE sensors are concatenated as the input matrix for the JSRC based classifier. Last, the backtracking simultaneous orthogonal matching pursuit (BSOMP) algorithm is proposed to solve the JSRC problem aiming to get the rub-impact classification results. The BSOMP has the advantages of not requiring the sparsity to be known as well as deleting unreliable atoms. Experiments are carried out on real-world data sets collected from in our laboratory. The results indicate that the JSRC method with multiple AE sensors has higher rub-impact classification accuracies when compared to the SRC method with a single AE sensor and the proposed BSOMP algorithm is more flexible and it performs better than the traditional SOMP algorithm for solving the JSRC method.
Wake and structure model for simulation of cross-flow/in-line vortex induced vibration of marine risers
Authors: Komachi Younes , Mazaheri Said , Tabeshpour Mohammad R.
Published: February 2018

Three dimensional responses of riser subjected to Vortex Induced Vibration (VIV) are investigated. Proportionality relations of stress and fatigue damage are mentioned. A computer code has been developed for time domain modeling of VIV of riser accounting for both Cross-Flow (CF) and In-Line (IL) vibration. The wake oscillator model is used to calculate the VIV of each strip. The wake oscillators are coupled to the dynamics of the long riser, while the Newmark-beta method is used for evaluating the structural dynamics of riser. The wake dynamics, including IL and CF vibrations, is represented using a pair of non-linear Van der Pol equations that solved using modified Euler method. The existing experimental and numerical results for stepped and sheared current are used to validate the proposed model and the results show reasonable agreement. The proposed model was implemented on Amir-Kabir semi-submersible riser deployed at the water depth of 713 meters of Caspian Sea. CF/IL VIV of this riser is simulated for various current velocities. The results show that although displacement amplitude of IL direction is lower than CF direction but because of higher curvature, stress values of IL direction for some cases can be higher than CF direction. Also because of higher frequency of IL direction, fatigue damage of this direction can be higher than CF one in some cases. It is shown that with increasing of current velocity; however, variation of displacement amplitude of two directions is low but stress increased and fatigue damage also increased with higher rate. For lower velocities which the modes are controlled with tension, stress and fatigue damage of IL direction is higher than CF direction.
Study on kinetic characteristics of a reciprocating mechanism with clearances
Authors: Zou Yan , Xu Cheng , Luo Shao Min
Published: February 2018

Clearances in mechanism are inevitable due to the errors from assembly, manufacture and wear. To study the kinetic characteristics of a typical automatic mechanism and the influence of clearances, an experimental device based on a reciprocating mechanism with clearances was set up, and a high speed camera system (HSCS) was used to record the mechanism motions. While the kinetic characteristics were analyzed based on the experimental data from HSCS, a coefficient of initial pressure of gas chamber used to characterize the randomness of the gunpowder gas force was proposed and its distribution was obtained. Meanwhile, the stiffness coefficient and damping coefficient of counterrecoil spring were identified. The virtual prototype model of this automatic mechanism was established. It’s found that the kinetic characteristics from the simulation and the experimental results of stochastic parameters and identification parameters are coincident approximately. Finally, the influence of guide rail’s clearances on kinetic characteristics based on the virtual prototype model was studied.
Research on torsional vibration reduction of crankshaft in off-road diesel engine by simulation and experiment
Authors: Sun Liming , Luo Fuqiang , Shang Tansu , Chen Hongtao , Moro Adams
Published: February 2018

Formerly, torsional vibration of crankshaft in off-highway diesel engine (agricultural machinery) were given little attention at their developmental stages, however with increasing agricultural activities, numerous torsional vibration problems have been noted to occur in agricultural machinery, especially in their diesel engines. This results in engine vibration, crankshaft failure and undesirable engine noise. In this paper, a six-cylinder four-stroke inline diesel engine’s crankshaft model was developed using AVL Excite Designer. After experimentally validating the model, it was used to numerically determine the torsional vibrations of a crankshaft. For the reduction of torsional vibration, two methods of crankshaft improvements were proposed based on simulation results. The first method, is to decrease the inertia of the crank pulley while the second, involves the replacement of the crank pulley with a torsional vibration damper. To ensure minimal engine alterations and cost effectiveness, the second improvement method was adopted for improving torsional vibration. Afterwards, engine radiating noise and surface vibration measurements were conducted to ensure that the required limits were achieved by the improved engine. The simulation, experiment and the improvement process of the crankshaft torsional vibration are documented further in this research. These improvements have applicable values in the developmental or quality enhancement stage of diesel engines used in agricultural machinery.
Model reaching adaptive-robust control law for vibration isolation systems with parametric uncertainty
Authors: Burkan Recep , Özgüney Ömür Can , Özbek Cengiz
Published: February 2018

Adaptive control has been used for active vibration isolation and vehicle suspensions systems. A model reference adaptive control law is used for the plant to track the ideal reference model. In a model reaching adaptive control approach, the ideal of a skyhook target without using a reference model is achieved. In this paper, a novel approach, a model reaching adaptive-robust control law is studied for active vibration isolation systems. A dynamic manifold for ideal system is defined using the ideal of a skyhook target model system parameters. First, a new Lyapunov function is defined. Based on the Lyapunov stability theory, a model reaching adaptive and a robust control laws are derived for the uncertain system to reach the ideal manifold. Parameters and upper bounding functions are estimated as a trigonometric function depending on the relative displacements, velocities and the defined manifold. The developed adaptive and the robust compensators are combined and this combination is proposed as an adaptive-robust control law. After that, the controller is applied to a vehicle suspension system and the ideal of a skyhook target without using a reference model is achieved. The results also show that the proposed robust control law can increase the comfort of the vehicle active suspension systems and the ride comfort is remarkably increased.
Numerical simulation on the aerodynamic performance of the high-speed train under crosswinds
Authors: Yang Ai Min , Zhang Ce , Li Shan Shan , Zhang Ling , Men Xiao Jun , Kong Fan Bei , He Shi Yu
Published: February 2018

With the continuously increased speed of the high-speed train, the lateral aerodynamic performance of high-speed trains has attracted more and more attention. Under strong crosswinds, the aerodynamic performance of trains deteriorate and air drag, lift and lateral forces borne by trains quickly increase, which has an impact on the lateral stability of trains and even leads to train derailment. This paper adopted computational fluid dynamics theory to establish an aerodynamic model for a high-speed train, computed aerodynamic forces and moments acting on the high-speed train and obtained the unsteady flow field of the high-speed train. In the meanwhile, this paper combined with multi-body system dynamics theory to establish a system dynamics model for the train and analyzed the safe aerodynamic performance of the high-speed train under cross winds. Computational results showed: Under cross winds, the aerodynamic performance of the high-speed train had a random fluctuation. When wind direction angle was 90°, aerodynamic forces (drag, lift and lateral forces) and moments (overturning moment, shaking moment and nodding moment) borne by the high-speed train were the largest; train speed was a main factor affecting the size of positive pressures of train and cross wind velocity had no obvious impacts on the positive and negative pressures of train body; the aerodynamic forces and moments of the high-speed train had a random fluctuation within a certain range with time; the frequency for the peak value of power spectral density of lateral forces of head train was within 25 Hz and the peak value of power spectral density was the largest when the main frequency was 1.6 Hz; the frequency for the peak value of power spectral density of overturning moment of head train was within 20 Hz and main frequency was 0.57 Hz. When the cross wind speed was 15 m/s, all safety indexes of the high-speed train running at the speed of 250 km/h were within the range of limited values and satisfied design requirements. Aerodynamic performance of the high-speed train with the suction chamber under the cross wind was computed and compared with original results. Aerodynamic force and force moments of the high-speed train under cross wind will be reduced obviously and running safety of the high-speed train can be improved through application of the suction chamber.
Direct force control of upper-limb exoskeleton based on fuzzy adaptive algorithm
Authors: Tang Jing , Zheng Jianbin , Wang Yang
Published: February 2018

In order to synchronize human and machine positions and minimize human-machine interaction forces in exoskeleton control, we present a two-degree-of-freedom (2-DOF) upper-limb exoskeleton model with power enhancement and direct force control strategy based on fuzzy adaptive algorithm. The conventional PD controller is widely used in exoskeleton control because it is model independent and its gains can be easily tuned. However, the speed of movement of the operator and the mass of external load are uncertain in practice; hence, the parameters of a conventional PD controller have to be adjusted according to the velocity of the motion and external loads to ensure the effectiveness of trajectory tracking. Additionally, there is a lag in the response time when the operator starts to move or changes direction suddenly. Therefore, this study proposes the use of an adaptive controller combining the fuzzy set techniques and PD controller to improve trajectory tracking. Robustness testing of the fuzzy PD controller for the external load uncertainty and motion velocity change are also investigated. The simulation results clearly indicate the superior performance of the fuzzy adaptive PD controller over the conventional one for tracking performance with external load uncertainty and motion velocity variance.
Nonlinear robust adaptive NN control for variable-sweep aircraft
Authors: Ma Zongcheng , Feng Jinfu , Hu Junhua , Liu An
Published: February 2018

In this paper, we address the problem of altitude and velocity controllers design for variable-sweep aircraft with model uncertainties. The object is to maintain altitude and velocity during the wing transition process where mass distribution and aerodynamic parameters change significantly. Based on the functional decomposition, the longitudinal dynamics of the aircraft can be divided into altitude subsystem in non-affine pure feedback form and velocity subsystem. And then nonlinear robust adaptive NN velocity controller and altitude controller are designed with backstepping method to relax the prior requirements of aerodynamic parameters accuracy in linear LPV controller design. The method of filtered signal is used to circumvent the algebraic loop problem caused by the dynamics of non-affine pure feedback form. Dynamic surface control (DSC) and minimal learning parameters (MLP) techniques are employed to solve the problems of ‘explosion of complexity’ in the back-stepping method and the online updated parameters being too much. The robust terms have been introduced to eliminate the influences of approximation errors. According to the Lyapunov-LaSalle invariant set theorem, the semi-global boundedness and convergence of all the signals of the closed-loop system are proved. Simulation results are presented to illustrate the control algorithm with good performance.
Rolling bearing fault diagnosis based on improved complete ensemble empirical mode of decomposition with adaptive noise combined with minimum entropy deconvolution
Authors: Rabah Abdelkader , Abdelhafid Kaddour
Published: February 2018

The vibration signals provide useful information about the state of rolling bearing and the diagnosis of the faults requires an accurate analysis of these signals. Several methods have been developed for diagnosing rolling bearing faults by vibration signal analysis. In this paper, we present an improvement of the technique Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN), this technique is combined with the Minimum Entropy Deconvolution (MED) and the correlation coefficient to diagnose defects. First, the vibration signal was decomposed by the improved CEEMDAN decomposition into several oscillatory modes called Intrinsic Mode Function (IMF). After calculation of the correlation coefficients between the original signal and their IMFs, the modes with higher coefficients are selected as the relevant modes. Secondly, the MED technique is applied to the selected modes in order to improve the sensitivity of the scalar and frequency indicators of faults detection. Finally, kurtosis and envelope analysis are used to detect and locate the defect position. The simulation is carried out using the Case Western University data base and the results obtained show that the proposed method provides very good results for the early detection and diagnosis of defects and can efficiently extract the defective characteristics of the rolling bearing.
Dynamical response of fractional-order nonlinear system with combined parametric and forcing excitation
Authors: Xing Hai Jun , Xiao Ke Shi , Song Peng Sai , Li Lin Ru
Published: February 2018

A dynamical analysis of a Mathieu-van der Pol-Duffing nonlinear system with fractional-order derivative under combined parametric and forcing excitation is studied in this paper. The approximate analytical solution is researched for 1/2 sub harmonic resonance coupled with primary parametric resonance based on the improved averaging approach. The steady-state periodic solution including its stability condition is established. The equivalent linear stiffness coefficient (ELDC) and equivalent linear damping coefficient (ELSC) for this nonlinear fractional-order oscillator are defined. Then, the numerical simulations are presented in three typical cases by iterative algorithms. The time history, phase portrait, FFT spectrum and Poincare maps are shown to explain the system response. Some different responses, such as quasi-periodic, multi-periodic and single periodic behaviors are observed and investigated. The results of comparisons between the numerical solutions and the approximate analytical solutions in three typical cases show the correctness of the analytical solutions. The influences of the fractional-order parameters on the system dynamical response are researched based on the ELDC and ELSC. Through analysis, it could be found that the increase of the fractional-order coefficient would result in the rightward and downward movements of the amplitude-frequency curves. The increase of the fractional-order coefficient will also move the bifurcation point rightwards and will make the existing range of steady-state solution larger. It could also be found that the ELSC will become larger and ELDC smaller when the fractional order is closer to zero, so that the decrease of the fractional order would make the response amplitude larger. At last, the detailed conclusions are summarized, which is beneficial to design and control this kind of fractional-order nonlinear system.
Vibration control of rotating piezo-composite blade beam with CUS configuration based on optimal LQG controller
Authors: Liu Tingrui , Liu Guifang
Published: February 2018

Vibration control of rotating composite blade beam with piezoelectric patch embedded is investigated. Stall flutter of piezo-composite blade driven by nonlinear aerodynamic forces is analyzed based on anisotropic circumferentially uniform stiffness (CUS) configuration. The blade is modeled as single-cell thin-walled beam structure, exhibiting the couplings among three displacements of vertical bending, lateral bending and transverse shear deformation, with structural tailoring implemented. The transversely piezoelectric actuating element is embedded in a manner such that its surface is parallel to the mid-surface of the blade beam. Piezoelectric damping ratios of rotating piezo-composite blade are described, with influences of different ply angles and rotating speeds illustrated. The flutter suppression for stall aeroelastic behavior based on an optimal LQG controller (OLC) with a dynamic regulator is highlighted with obvious effects demonstrated. In contrast with conventional LQG controller, the superiority of OLC controller is apparently demonstrated by time response and piezoelectric feedback voltage. Analytical proof of the structural modeling and feasibility analysis of the physical realization of the OLC algorithm are also investigated by comparisons of different modeling theories, and demonstrated by experimental platform.