bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Smoking Cessation On Tooth Loss: A Systematic Review With Meta-Analysis
Authors: Souto Maria Luisa Silveira , Rovai Emanuel Silva , Villar Cristina Cunha , Braga Mariana Minatel , Pannuti Claudio Mendes
Published: October 2019

Background: Smoking is a major risk factor for periodontitis and tooth loss. Smoking cessation has a positive impact in periodontal treatment. However, so far, no systematic reviewhas evaluatedthe effect of smoking cessation on tooth loss. Therefore, this review aimed to evaluate if smoking cessation reduces the risk of tooth loss. Methods: Observational (cross-sectional and longitudinal) studiesthat investigated the association between smoking cessation and tooth loss were included. MEDLINE, EMBASE and LILACS databases were searched for articles published up to November 2018. Pooled results for subgroups of current and former smokers were compared in meta-analysis. Meta-regression was used to test the influence of smoking status on estimates and explore the heterogeneity. Results: Of 230 potentially relevant publications, 21 studies were included in the qualitative review and 12 in the quantitative analysis. Meta-analysis of cross-sectional studies did not show any differences between former and current smokers in the chance of losing 1 or more teeth (OR = 1.00; 95% CI = 0.80 to 1.24, I 2 = 80%), losing more than 8 teeth (OR = 1.02; 95% CI = 0.78 to 1.32, I 2 = 0%) or being edentulous (OR = 1.37; 95% CI = 0.94 to 1.99, I 2 = 98%). Meta-analysis from longitudinal studies showed that, when compared to never smokers, former smokers presented no increased risk of tooth loss (RR = 1.15; 95% CI = 0.98 to 1.35, I 2 = 76%), while current smokers presented an increased risk of tooth loss (RR = 2.60; 95% CI = 2.29 to 2.96, I 2 = 61%). Meta-regression showed that, among former smokers, the time of cessation was the variable that better explained heterogeneity (approximately 60%). Conclusions: Risk for tooth loss in former smokers is comparable to that of never smokers. Moreover, former smokers have a reduced risk of tooth loss, when compared to current smokers.
Oral health of children and adolescents with or without attention deficit hyperactivity disorder (ADHD) living in residential care in rural Rhineland-Palatinate, Germany
Authors: Ehlers Vicky , Callaway Angelika , Wantzen Sophia , Patyna Michael , Deschner James , Azrak Birgül
Published: October 2019

Background: Attention deficit hyperactivity disorder (ADHD) is defined as childhood neurobehavioural disorder. Due to short attention span, oral hygiene and dental treatment of such individuals can be challenging. Aim of this study was to evaluate the oral health of children and adolescents with and without ADHD living in residential care in rural Rhineland-Palatinate, Germany.
Methods: Included in the study were 79 participants (male/female:58/21, age 9-15 years) living in residential care: 34 participants with ADHD and 45 participants without ADHD (control). Oral examination included the following parameters decayed, missing, filled teeth in the primary dentition (dmft), decayed, missing, filled surfaces/teeth in the secondary dentition (DMFS/DMFT), approximal plaque index (API), bruxism and orthodontic treatment. Additionally, oral hygiene, last dental visit and treatment performed, and dietary habits were assessed by questionnaire.
Results: There were no significant differences in dmft, API, bruxism and oral hygiene habits between groups. However, participants with ADHD tended to have higher DMFS/DMFT values than the control group. Ongoing orthodontic treatment was found more often in the control group. The ADHD group tended to consume acidic/sugary beverages and sweet snacks more often than the controls. Different treatments (control visit/prophylaxis, dental therapy, orthodontic treatment) were performed at the last dental visit in the two groups.
Conclusions: Within the limitations of this study, oral health was similar in children and adolescents with or without ADHD from the same residential care setting. Parents/guardians need instructions for better supervision of oral hygiene and dietary habits to improve the poor oral health of children with or without ADHD.
Malic enzyme 1 may be a novel target of breast cancer metastasis
Authors: Liu Chang , Lin Shuchen , Zhao Yannan , Cao Jun , Tao Zhonghua , Hu Xichun
Published: October 2019

Background Malic enzyme 1 (ME1) catalyzes malate to pyruvate and thus promotes glycolysis, playing a part in the Warburg effect. It also has a potential role in tumor progression, but its function in breast cancer remains to be fully clarified. This work aimed to investigate the prognostic value of ME1 and its possible mechanism in breast cancer.Methods We evaluated ME1 expression in 220 early breast cancer patients with tissue microarray-based immunohistochemistry and explored the relationships between ME1 expression and clinicopathological features. Survival analyses were further performed to determine its prognostic value. The public database was used to confirm tissue microarray results. Moreover, we profiled ME1 expression in breast cancer cell lines via western blotting, and then assessed it in cell viability and motility via Cell counting kit-8 (CCK-8), colony formation, transwell migration and invasion assays. Reactive oxygen species (ROS) was detected by dihydroethidium (DHE) and 2’,7’-Dichlorodihydrofluorescein diacetate (DCFH-DA).Results In breast cancer tissues, high ME1 expression was significantly associated with larger tumor size, more lymph node metastasis and more extensive lymph-vascular invasion. Survival analysis showed high ME1 expression was significantly correlated with worse recurrence free survival (RFS). Multivariate analysis further identified high ME1 expression as an independent prognostic factor for RFS, which was confirmed by mRNA results in the public database. In vitro , human epidermal growth factor receptor-2 positive and triple negative breast cancer cell lines showed higher expression of ME1, while Luminal cell lines showed lower expression of ME1. Upregulation of ME1 by transfecting MCF-7 cells with virus vector remarkably enhanced viability and motility, epithelial-mesenchymal transition (EMT), and decreased ROS levels, whereas knockdown of this gene in MDA-MB-468 cells produced totally opposite effects as expected. More important, when pretreated with hydrogen peroxide, an oxidizing agent, MCF-7 cells overexpressing ME1 lost its motility, whereas MDA-MB-468 cells with knock-down of ME1 restored its motility when pretreated with N-acetyl cysteine, an antioxidant.Conclusions To our knowledge, these clinical and experiment work first suggested that ME1 may be a potential therapeutic target for breast cancer metastasis, and its biological effect is mainly controlled by manipulating ROS.
Psychometric Properties of Instrumented Postural Sway Measures Recorded in Community Settings in Independent Living Older Adults
Authors: Alqahtani Bader , Sparto Patrick J. , Whitney Susan L. , Greenspan Susan L. , Perera Subashan , Brach Jennifer S.
Published: October 2019

Background: In the last few decades, research related to balance in older adults has been conducted in lab-based settings. The lack of portability and high cost that is associated with the current gold standard methods to quantify body balance, limits their application to community settings such as independent living facilities. The purpose of the study was to examine the test-retest reliability and the convergent validity of static standing balance performance using an accelerometer device. Methods: A total of 131 subjects (85% female, mean age 80 ± 8 years) were included for the validity aim, and a sample of 38 subjects were enrolled in the reliability testing (89% female, mean age 76 ± 7 years). Acceleration data in the anterior-posterior and medial-lateral directions was collected for different standing balance conditions. Test-retest reliability was assessed over two testing visits occurring one week apart. Spearman’s rank correlation coefficient was used to test convergent validity at baseline. Results: Balance measurements showed good to excellent reliability in most of measured parameters and were correlated with mobility measurements. Conclusions: Using a portable accelerometer to quantify static standing postural control provides reliable measurements in community settings.
Epidemiological, Clinical characteristics and Drug resistance situation of Culture-confirmed Children TBM in Southwest of China: A 6-Year Retrospective Study
Authors: Wang Dong-Mei , Li Qing-Feng , Zhu Ma , Wu Gui-Hui , Li Xi , Xu Yuan-Hong , Zhong Jing , Luo Jia , Li Ying-Jie , Ying Bin-Wu , Tao Chuan-Min
Published: October 2019

Background : Sichuan is a province located in southwestern China, which have a higher incidence of tuberculosis (TB).This study aimed to analyze the epidemiological, clinical characteristics, and drug resistance in culture-confirmed children with Tuberculosis meningitis (TBM) in Southwest of China.
Materials and Methods: We performed a retrospective study of children with cerebrospinal fluid (CSF) culture-confirmed TBM who were <14 years of age between January 2013 and December 2018 at Public Health Clinical Center of Chengdu (PHCCC). Mycobacterium tuberculosis (MTB) drug sensitivity testing (DST) was performed using the MicroDST TM method. The age, gender, family history of tuberculosis, status of Bacillus Calmette–Guérin (BCG) vaccination, residential areas information, clinical, laboratory and radiological features were recorded. Data were analyzed using SPSS Statistics Client 25.0, and the change in drug resistance rate was analyzed using the Cruskal-Wallis test.
Results: From 319 TBM initially recruited patients,42 cases were Mycobacterialculture-positive, with the positive rate of 13.2 per 100 patients. Theirmedian age was nine years, sex distribution was equal. Among 42 patients who were enrolled in the study, 1/42 (2.38%) died. Children with TBM in the southwest of China were mainly concentrated in the minority areas of western Sichuan. In fact, 34/42 (81.0%) patients with TBM belonged to ethnic minorities, and only 2/42 (4.76%) had BCG vaccination histories.All the 42 patients had varying degrees of chest X-rays changes and 18/42 (42.9%) merger of extracranial TB. Fever and headache were the most common presenting symptom. Thirty-five (83.3%) patients suffered from neck stiffness and 30/42 (71.4%) had high CSF pressure. DST results showed that the resistance rate was high; resistance to any anti-tuberculosis drug (ATD) was 13 (31.0%), and to multidrug-resistant tuberculosis (MDR-TB) and XDR it was 2 (4.8%) and 1 (2.4%), respectively.
Conclusions : TBM in children in Southwest China was mainly concentrated in the minority areas of western Sichuan. The most common symptoms were fever, headache and neck stiffness and all patients had positive chest X-ray findings. High rates of drug resistance were founded. In addition, more than 95% of patients did not receive BCG vaccination at birth.
Psychometric Properties of the School Liking and Avoidance Questionnaire in a Turkish Preschool Sample
Authors: Nur İmray , Aktaş Arnas Yaşare
Published: October 2019

In
this study, the replicability of the factor structure of The School Liking and
Avoidance Questionnaire for Turkish preschool children and the psychometric
properties of the scale were investigated. The SLAQ consists of 14 items and is
used to assess children's emotional and behavioral participation in school
based on children's perceptions. 345 children aged 5-6 years were included in
the study. The findings of exploratory and confirmatory factor analyses, to
assess the validity of the scale in Turkish culture, have identified two
distinct but related factors: school liking and school avoidance. This result
is consistent with the original scale and the adaptation studies in different
cultures. However, there were no significant correlations between children and
teacher reports on school liking and school avoidance subdimensions. Cronbach's
Alpha and test-retest ratios for subdimensions showed adequate psychometric
properties. This data support the Turkish version of the SLAQ as a valid and
reliable tool, similar to the original version.
Penguasa, Tuhan, dan Rakyat: Membaca Apokalips Daniel 7 sebagai Subversi
Authors: Setio Robert
Published: October 2019

Because of its cryptic nature apocalypse Daniel 7 has been interpreted in many ways. Often it is linked to the end of time teachings. This kind of interpretation is problematic. First, while emphasizing the dark side of the prophecy, it fails to capture its main intention which is optimism toward the future. Second, apocalypse contains dualistic ideas, but, they are not supposed to be separated, let alone taking one side over the other. Apocalyptic dualism should be treated as an oscillating, always negotiating positions, tensional but creativecollisions. This article shows a reading of apocalypse that reveals dualism as an integrated entity. It also considers theological consequences of such a reading. While being placed within the world’s history, God is deeply involved in worldly drama which consists of tragedy, as well as, comedy. On the political side, this reading demonstrates that imperial history does not run by itself, but, always prones to subversive movements.
Does enterprise risk management impact accounting quality? Evidence from the Nigerian financial institutions
Authors: Erin Olayinka Adedayo , Uwuigbe Uwalomwa , Sylvester Eriabie , Ranti Uwuigbe Olubukola , Osereme Amiolemen Omoike
Published: October 2019

This research empirically looked at Enterprise Risk Management impact on accounting quality of selected listed firms in the Nigerian financial sector. The study engaged the use of content analysis of the selected listed firms’ annual financial reports and corporate websites in determining the ERM disclosure index and its impact on accounting quality for a period of five years (pre-ERM period) (2007–2011) and another five years period (post-ERM period) (2013–2017). In attaining the proposed objectives, the study employed the panel Generalized Method of Moments estimator to test the hypotheses and find out the relationship between the variables. The study observed from the findings that there is no significant association between enterprise risk management and accounting quality during the pre-ERM period. This study adds to the body of knowledge in the area of corporate reporting, risk disclosure, risk management and accounting quality in emerging economies especially the Sub-Saharan African countries.
On the issue of acceleration of the compensating mass in an automatic balancing device with a horizontal axis of rotation
Authors: Strautmanis Guntis , Mezitis Mareks , Strautmane Valentina , Gorbenko Alexander
Published: October 2019

Among the ways to reduce vibrations of rotary machines with a vertical or horizontal axis of rotation is the use of ball-type automatic balancing devices. At the same time, the acceleration of compensating masses in the automatic balancing device with an annular cross-section of the housing showed that to accelerate the compensating masses to the operating speed of the rotor, it is necessary to provide the initial velocity due to the influence of gravity at the initial stage of acceleration. The value of the initial velocity of compensating masses depends on the parameters of the elastic suspension of the rotor, the size of the compensating mass, the coefficient of rolling friction between the compensating mass and the inner surface of the housing of the automatic balancing device and other parameters. In this work, the influence of the rolling friction coefficient and other parameters of the rotor system on the acceleration of compensating masses is studied, recommendations on the selection of parameters are given.
Experimental study on ground vibration response in gun firing environment
Authors: Wang Baoyuan , Lei Qiang , Wang Dongying
Published: October 2019

In order to know the ground vibration response law of gun firing environment, a large caliber gun was taken as the research object, and the ground vibration response law of gun firing environment was tested. Several acceleration sensors are arranged on the ground around the gun, and the ground vibration acceleration response laws of the gun position in the firing environment are obtained. The firing of gun will cause the ground vibration of gun position. In the bore period, as long as the projectile is fired, there will be acceleration response on the ground of the gun position. The maximum acceleration response of ground vibration in the bore period of projectile is less than 0.03 g. The maximum acceleration response of ground vibration is less than 0.1 g after projectile exits the muzzle and before the muzzle shock wave reaches the ground. If the sensor bracket is placed on the ground around the gun, when the muzzle shock wave does not reach the sensor position, the influence of ground vibration on the sensor can be neglected. Once the muzzle shock wave reaches the sensor position, its influence should be paid attention to.
Static analysis of dynamic servo tool rest considering the influence of precision error
Authors: Li Xiaolei , Chen Mingjun
Published: October 2019

The analysis of the reliability of dynamic servo tool rest using traditional methods is inaccurate because the influences of the accuracy of gear machining and assembly are not considered. In this study, a static analysis method for dynamic servo tool rest is conducted considering the influence of accuracy error. Firstly, the working principle of tool rest is analysed, and its working process is divided into two actions, namely, initial positioning and locking. Secondly, the error sources of dynamic servo tool rest are investigated, and the transmission angle error is divided into two kinds, namely, assembly error of shafting and machining error of gear. The static analysis of tool rest is performed by considering the influence of the transmission error of the tool rest. Results show that the assembly, machining and locking forces of the fixed tooth disc of the dynamic servo tool rest have important effects.
Temperature stress of waste bunker in municipal solid waste incineration power generation plant
Authors: Wu Qi , Dong Yinfeng , Rao Jianli
Published: October 2019

With large number of municipal solid waste incineration power generation plants appearing, serious environmental pollution will be caused if temperature cracks appear in waste bunkers. To reveal the interaction between the surrounding soil and bunker walls under the action of temperature, a finite element model is established. Considering the surrounding soil layer, the characteristics and influence laws of the interaction between the municipal solid waste bunker and the soil under different temperature conditions are studied. The simulation results show that the existence of the surrounding soil layer will affect the stress distribution, mainly at the bottom of the bunker and the surface of the bunker wall. Due to the thermal expansion and contraction, the municipal solid waste bunker is pressed during the heating process. In the process of cooling, there will be excessive tensile stress at the bottom of the bunker. To address this problem, expansion belt is arranged at the stress concentration portion to reduce the stress concentration. This measure proves to be effective according to analysis results, which provides a reference for the design of municipal solid waste bunkers.
Effect of temperature stress on main structure in waste incineration power generation plant
Authors: Rao Jianli , Dong Yinfeng , Wu Qi
Published: October 2019

Waste incineration power station includes many functional structures, such as garbage discharge, storage, sorting and feeding units, boiler unit, tail gas treatment unit, leachate treatment unit, and coal storage unit. The structural forms of each part are different. Because of the particularity of garbage, structure units are required to be as close as possible and temperature joints should not be set up for the sake of possible leakage of exhaust gas or effluent liquor, so various structural units are integrated, which leads to the difficulty in structure design, and thermal stress cannot be neglected. In order to understand the effect temperature stress on main plant structures, a finite element model is established to study the distribution of thermal stress of the whole structure under three conditions: heating in summer, cooling in winter and heating in winter. It is found the influence of temperature on frame beam, column and steel space truss can be neglected, and the thermal stress on floor cannot be neglected [1]. The maximum stress is mainly distributed on both edges of floor along the longitude direction of structure. For those regions where stress concentration occurs, reinforcement bands or reinforcement mesh can be used to reduce the tensile stress. The analysis results show that this measure is effective and provides a reference for the design of the main structure of waste incineration power plant. This paper innovatively analyses the structure system of main workshop of refuse incineration power plant, which is composed of steel structure and concrete structure, and describes the skills and key points of complex system modeling. According to different seasons and heating temperature difference, the temperature stress on the surface of the structure is analyzed, which provides a reference for calculating degree stress and temperature difference of the similar structure system. The weak part of resistance to temperature stress in the structure system composed of concrete structure and steel structure is found out, and the corresponding solutions are put forward, which provides guidance for the construction of the main workshop of refuse incineration power station.
Improving ride comfort for vibratory roller utilizing semi-active hydraulic cab mounts with control optimization
Authors: Jiao Renqiang , Nguyen Vanliem
Published: October 2019

Hydraulic mounts can provide a better vibration attenuation performance than elastomeric mounts especially in the low frequency range. However, it is incapable of providing a response-dependent damper for the mount system to improve the ride comfort. In this study, a semi-active hydraulic cab mount (SHM) with control optimization was designed to improve ride comfort for the heavy vibratory roller. And a 7-DOF non-linear dynamic model of the vehicle was established for evaluation of the performance of hydraulic cab mounts based on different control optimization algorithms. To simulate roughness height the ISO level D road surface and deformed soil model were employed under the compaction work condition. The optimization study for two performance objectives as measured by responses of the vertical driver’s seat and cab pitch angle was carried out. It was shown that the SHM optimized by the fuzzy logic and proportional, integral, derivative controller methods (FLC-PID) giving best optimum values of the objective vector as compare to by multi-objective genetic algorithm (MOGA) and PID controller based on genetic algorithm (GA-PID).
Defect elimination in torsional harmonic reducer based on harmonic resonance
Authors: Huang Dishan , Zong Peng , Gu Jingjun
Published: October 2019

This paper will introduce the torsional vibration test method and signal analysis for a harmonic reducer in industrial robot. The harmonic reducer is generally applied to the fifth and sixth axes of the industrial robots, and the torsional vibration will affect the mechanical performance. To understand the torsional vibration condition of the harmonic reducer, the test device is set up through loading the corresponding moment of inertia. In the study, the curve of torsional characteristic is obtained, and it can be used to assess the mechanical performance; Using zoom spectrum technology on harmonic resonance, the characteristic frequency is identified in detail. The manufacturing defect of the harmonic reducer is diagnosed based on characteristic frequencies of its transmission, and defect elimination is successfully realized by adjustment of components in the harmonic driver; Some nonlinear vibration characteristics caused by stiffness with time periodic dependent, including bi-spectrum and harmonic resonance, etc., are investigated. The experimental results show that the test and analysis of torsional vibration have positive significance for the online quality assembly assurance of harmonic reducer.
Study on blast-induced vibrations of a tunnel cross section
Authors: Jiangbo Xu , Changgen Yan , Han Bao , Pengtao Yu
Published: October 2019

Construction blasting in a tunnel in deep-buried soft rock will undoubtedly influence the cross section of the tunnel. Taking the deep-buried soft rock tunnel as the research background, a field monitoring experiment of the tunnel blast-induced vibrations is carried out. The cross section was established using 5 monitoring points to collect the peak particle velocity (PPV) data and frequency spectrum data. The results show that the maximum horizontal radial component of the blast-induced vibration velocity is greater than the maximum vertical component in the deep soft rock tunnel, and the maximum vertical component is greater than the horizontal tangential component. Due to the presence of an inclined shaft, the high domain frequencies have an amplification effect on the tunnel, while low frequencies do not exhibit significant amplification effects.
Structural-acoustic modeling and analysis of an engineering machinery cab in the mid-frequency range
Authors: Gong Can , Jiao Renqiang , Nguyen Vanliem
Published: October 2019

The hybrid finite element method and statistical energy method was used to study the vibro-acoustic coupling characteristics of an engineering vehicle cab. The parameters of the statistical energy method, such as modal densities, damping loss factors and coupling loss factors of substructures, were acquired by numerical and analytical methods. The acoustic-structure coupling of the cab was established based on the modal densities of substructures. The vibration and noise excitations of the cab were measured by test and the sound pressure level response of the driver’s ear was predicted. It was shown that the prediction results based on the hybrid method are in agreement with the experiments and the proposed method can be applied to predict the mid-frequency response of complex vibro-acoustic coupling systems with a moderate computational cost and accuracy.
Construction of 12 DOFs spur gear coupling dynamic model
Authors: Lv Huanchao , Li Zhengminqing , Zhu Wenlin , Tang Xin , Gao Jie , Zhu Rupeng
Published: October 2019

A 12-degree-of-freedom (DOF) spur gear dynamic model is constructed, which is coupled by the mesh gear pair and the gearbox. The construction method of spur gear coupling dynamic model, based on lumped mass method, is better than finite element method, due to higher modeling efficiency. The work would be benefit to spur gear coupling dynamic modeling and analyses.
Fixed point problems of nonexpansive mappings for nononvex set in Hilbert spaces
Authors: Wu Xianbing
Published: October 2019

In this paper, we introduce a new concept of W-nonexpansive mappings and obtain fixed point theorems for nonexpansive mappings for non-convex set. Our results resolve fixed pointed problem that nonexpansive mappings be not on closed convex set, and it extends fixed point theorems for nonexpansive mappings.
Study on penetration characteristics of honeycomb aluminum
Authors: Du Wenbin , Chao Hongxiao , Lei Qiang , Ren Junlong , Wang Dongyin
Published: October 2019

In order to analyze the mechanical properties of projectile penetrating honeycomb aluminum, a dynamic nonlinear finite element model of projectile penetrating honeycomb aluminum was established and verified by experiments. It is found that the numerical simulation results of projectile penetration into honeycomb aluminum are consistent with the acceleration variation of the test. When the projectile penetrates into the honeycomb aluminum, the acceleration waveform is trapezoidal and the peak and pulse width of the acceleration are related to the velocity of the projectile and the wall thickness of the honeycomb aluminum material. With the increase of the velocity of the projectile, the peak value of the acceleration increases and the pulse width of the acceleration decreases. With the increase of the wall thickness of honeycomb aluminum, the peak value of acceleration increases, while the pulse width of acceleration decreases.
Influence of mass unbalancing of three-cylinder engine on idle vibration based on powertrain model
Authors: Guo Rong , Zhou Ziwei
Published: October 2019

This paper proposes a model of three-cylinder engine excitation which includes the characteristics of the mass unbalancing. Then, a powertrain model is established to analyze the response of powertrain mounts under different balancing strategy of the mass unbalancing during idle condition. Simulation is performed based on the powertrain model to demonstrate how different balancing strategies of three-cylinder engines influence the design of powertrain mounts.
The control strength quantification analysis of outer pendulum rod for double inverted pendulum
Authors: Fu Wencong , Wang Chan , Xu Peng , Dan Yuanhong
Published: October 2019

Due to the complexity of the dynamics characteristics of an inverted pendulum, and the problem that the linearization analyze method cannot satisfy the controlling requirement, a nonlinear dynamics analyze method was proposed. Through decoupling the dynamics model of a double inverted pendulum, the outer pendulum rod motion equation was derived. And then, aiming at the control strength function of outer pendulum rod, the qualitative and quantitative relationship between spatial position of pendulum rod and the control strength of outer rod, and the quantification relationship between dynamics parameters and the control strength of outer rod were separately analyzed. And the simulation verified the correctness of the analysis.
Research on the dynamic characteristics of the squeeze film damper of a certain aero-engine
Authors: Liao Xue-Min , Luo Gui-Huo , Feng Zhao-Jun , Chen Li-Jia , Zheng Nan
Published: October 2019

Numerical methods were conducted to simulate the characteristics of SFD under different clearance, eccentricity and precession angular velocity and verified by bidirectional excitation experiments, which is comparatively leading initiative in characteristic measurement of SFD. In addition, finite difference method was introduced to derive Reynolds equation and SOR method to obtain the distribution of oil film, the convergence was also mathematical proof. The results indicate the rotor system keep large vibration state for a long time due to the increasing of actual critical speed of system, which result from the oil film stiffness increases nonlinear excessively with the increase of eccentricity; clearance make a great influence on SFD, especially SFD with large radial size should be kept within 2 ‰.
Vibration-based damage growth monitoring in beam-like structures
Authors: Sha Ganggang , Cao Maosen , Liu Jingqiang , Soman Rohan , Radzieński Maciej , Ostachowicz Wiesław
Published: October 2019

Damage growth monitoring plays an important role in providing early warning of structural failure. The existing methods for damage growth monitoring are mainly local inspection methods, such as acoustic emission. These methods need a priori knowledge of accessible damage vicinity, which may not be realized in practice. Hence, vibration-based global approach is adopted to overcome these difficulties. Natural frequency, as a global modal parameter, can be measured easily and is used for vibration-based damage growth monitoring in this study. A concept of damage-induced relative natural frequency change (RNFC) curve is defined first and its relation with mode shape is then derived analytically, giving a good way to approximate RNFC curves. For monitoring damage growth, a damage growth indicator is proposed based on RNFCs between two damaged stages of a beam. The effectiveness of the indicator for damage growth monitoring is proved by both numerical and experimental cases in beam-like structures.
Nonlinear crack assessment method in beams based on bispectrum-normal cloud model
Authors: Cui L. , Manoach E. , Xu W. , Pan L. X. , Cao M. S.
Published: October 2019

Fatigue damage in engineering structures is universal. The occurrence of fatigue cracks brings unpredictable hidden dangers to a structure in terms of safety and service performance. Traditional damage identification methods, such as power spectrum analysis, are mostly based on linear elasticity theory that cannot reflect the typical nonlinear characteristics of fatigue cracks and cannot meet the higher requirements of the signal analysis method put forward by current mass detection data. To solve this problem, a numerical model of a cantilever beam with a breathing crack is established in this study. A method for diagnosing fatigue damage is studied by combining bispectral analysis and a statistical normal cloud model, which characterize the nonlinear characteristics of the structure. This method can effectively describe the nonlinear characteristics of the structure and reasonably evaluate the degree of fatigue damage in the structure. The bispectrum-normal cloud model method proposed in this study overcomes the limitations of existing linear damage detection methods in nonlinear damage detection, and can improve the efficiency of signal analysis from a statistical point of view. It has good prospects for structural nonlinear damage assessment.
Damage detection in sluice hoist beams subject to excitation at resonance frequency band based on local primary frequency
Authors: Wei Q. Y. , Xu W. , Novák D. , Pukl R. , Li D. Y. , Cao M. S.
Published: October 2019

Cracks of sluice hoist beams due to the load and aging of the material threaten the safety of sluice structural system. As the one of the main methods of damage detection, the non-destructive detection method based on natural frequency is still insensitive to local damage. Therefore, this paper proposes a method for hoist beams damage detection driven by resonance frequency band based on local primary frequency in the local mode. Firstly, the possibility of damage detection based on local primary frequency is discussed and the procedure of determining resonance frequency band is explained. Then the damage identification index based on the change ratio of local primary frequency is provided. Finally, numerical results demonstrate the correctness and effectiveness of the proposed method. The proposed method can provide reference for damage detection of hoist beams and health monitoring of sluice structural system.
Sarcoide equino: revisión y actualización
Authors: Tuemmers Apablaza Christian Alex , Quezada Sandoval Gerardo Alonso
Published: October 2019

El sarcoide equino es la neoplasia más común de los équidos y representa más de la mitad de las neoplasias de la piel de los caballos. El objetivo del presente trabajo fue realizar una compilación del conocimiento actual sobre etiología, fisiopatología, diagnóstico y tratamiento de esta patología.El agente etiológico del sarcoide equino es el virus del papiloma bovino tipo 1 y 2 que afecta a équidos de todas las razas, sexos y edades. El traumacutáneo, la presencia de vectores como insectos y algunos haplotiposgenéticos son potenciales factores de riego. Se diagnostica a partir de la apariencia clínica, clasificándose en 6 tipos diferentes. La confirmación del diagnóstico se realiza mediante histopatología y las alternativas terapéuticas disponibles son muy variadas incluyendo cirugía, quimioterapia,radioterapia, inmunoterapia y otras. En conclusión, ésta es una patología de curso impredecible, no existiendo tratamiento efectivo por sí solo, ya que existe una alta probabilidad de recurrencia y solo el empleo de nuevas modalidades terapéuticas combinadas permite obtener mejores resultados. La prevención probablemente se verá facilitada en el futuro por el desarrollo de vacunas contra el virus del papiloma bovino.
Corrección quirúrgica de una fractura mandibular en una yegua por cerclaje interdentario: un reporte de caso
Authors: Cedeño Quevedo Darío Alejandro , Yandún M Lina Lucero , Portilla Domingues Elmer
Published: October 2019

Las fracturas de la mandíbula no son raras en equinos, siendo este el hueso de la cabeza más fracturada. En la mayoría de los casos, se abren y se ven involucrados tejidos blandos adyacentes. Como los huesos de la cabeza no son sometidos a fuerzas de carga de apoyo, la fijación de la fractura es menos desafiante. El presente trabajo describe el tratamiento quirúrgico en campo de una fractura mandibular en una yegua Criolla Colombiana de 64 meses de edad. Esta presenta mala oclusión con desgarro de la mucosa bucal. La proyección radiográfica oral muestra una fractura abierta transversal en el cuerpo mandibular a nivel de la región de la placa alveolar derecha. La anestesia se inicia con acepromazina (0,04mg/kg intramuscular) e inducción con xilacina (1,1 mg/kg) y ketamina (2,2 mg/kg Intravenosa). Se utilizó una anestesia total intravenosa con triple goteo para mantenimiento(2 g de ketamina + 500 mg de xilacina en 1 litro de guaifenesina al 5%) eninfusión constante (2–3 ml/kg/h). Después de limpiar y desbridar la herida se realiza una incisión a través de la mejilla sobre los premolares 406 y 407. Se perforó un orificio con una broca entre los espacios interalveolares de los premolares. Se pasó el alambre a través del agujero, el fue dirigido rostralmente y atado a través de los agujeros previamente hechos entre los incisivos 402 y 403. El alambre se torció para aumentar la compresión en la línea de la fractura. Después de apretar, los extremos de los cables se doblaron. El manejo posoperatorio se basó en la administración de ketoprofeno durante 5 días, Penicilina G (20.000 UI/kg) y desinfección diaria de la herida con Clorhexidina 0,12%. El alambre se dejó 4 semanas, observando una rápida cicatrización y consolidación de la fractura. El restablecimiento de las funciones deaprehensión y masticación se obtuvieron rápidamente. Se puede afirmar que esta técnica proporciona una estabilidad segura, es fácil de realizar y de bajo costo.
Metabolism prepartum and reproductive responses postpartum of Nellore cows supplemented in different periods of gestation
Authors: Contreras Marquez David Esteban , Fonseca Paulino Mário , Mageste de Almeida Daniel , Masa Ortega Román Enrique , Soares Martins Leandro , Sotelo Moreno Deilen Paff , Ramalho Moreira Thiago , dos Santos Edson , Vieira Pereira Vinicius Augusto , Arantes Campos Mateus
Published: October 2019

The purpose of this study was to determine the effect of cow’s grazing supplementation during pregnancy on the concentration of metabolites in blood and its relation with uterine involution and postpartum fertility. Twenty-seven Nellore cows were divided into three groups (n=9 for each group) as follows: UNS, unsupplemented during gestation; MID, supplemented from the 30 to 180-day of gestation; LATE, supplemented from the 181 to 281-day of gestation. Blood samples to determine the concentrations of NEFA, BHBA (β-hydroxybutyrate) and the glucose was performed on days 30, 105, 180, 230 and 281 of gestation. Fixed-time artificial insemination (FTAI) was performed in all matrices at forty-five days postpartum. Lower NEFA and BHBA concentrations it was observed in the MID and LATE group at 180 and 281 days of gestation respectively for each treatment. A higher glucose concentration was observed at 180 and 281 days of gestation for MID and LATE treatment, respectively. There were no differences in uterine involution and percentage of gestation between treatments. Pre-partum supplementation improves energy balance without altering uterine involution and postpartum fertility.
Selenio y glutatión peroxidasa en la nutrición porcina
Authors: Quisirumbay-Gaibor Jimmy Rolando , Vílchez Perales Carlos
Published: October 2019

El selenio (Se) es un mineral que cumple con funciones importantes en el organismo una de ellas es favorecer el equilibrio oxidativo al formar parte de la enzima glutatión peroxidasa. Existen dos fuentes de Se que pueden a través de la dieta ser suplementados a los animales, orgánica e inorgánica. La forma más antigua de Se ha sido la inorgánica por lo general el selenito de sodio y la orgánica es la Se-metionina que es el principal componente de la Se-levadura y recientemente la forma hidroxilada conocida como ácido 2-hidroxi-4-metil-seleno butanoico. La administración de Se-orgánico presenta mayores niveles de retención en el organismo, mayor concentración tisular en hígado, músculo, suero y mayor transferencia a lechones recién nacidos por medio del calostro y leche. En cerdos en etapas de finalización ha demostrado reducir las pérdidas por goteo al favorecer la retención de agua. Los niveles más recomendados de selenio en la nutrición porcina están entre 0,15 y 0,3 ppm y como fuente de elección Se-orgánico.
Barium exposure of an invasive breast cancer cluster investigation – quantitative drinking water chemistry for carcinogen search
Authors: Kamlade Paul
Published: October 2019

Quantitative review of oral barium exposure was conducted using drinking water metals data from the confirmed sixfold (18-fold15–39 years) Brisbane Australia invasive breast cancer cluster (IBC) investigation, which also included fivefold duct carcinoma in situ (DCIS). The new approach here was to assess sub-guideline on-site water system barium fluctuations and use cancer slope factor (CSF) firstly to profile match barium as a carcinogen, then correlate risk. Dissolved barium was converting, up to 71%, into non-dissolved forms in the cluster location; with only up to 3% in a comparison location. A CSF of approximately 330 (mg L−1)−1 gave a chemistry-based number of women of 12, consistent with 14 originally (mostly IBC), less 2 per general population biostatistics. The comparison location gave null women numbers. One-woman IBC correlated to 0.0018 mg/L barium, comparable to the US Environmental Protection Agency's (USEPA) 0.002 mg/L, 10−4 cancer risk for arsenic. The two- to fivefold San Diego USA IBC cluster had barium as the only metal in common with Brisbane; and, breast cancer alcohol risk factor fingered barium qualitatively. It is put that barium causes IBC and DCIS; proof submitted hereby to wider scrutiny. The relevant barium exposure was likely calcium coprecipitated.
Uncertainty of annual runoff projections in Lithuanian rivers under a future climate
Authors: Akstinas V. , Jakimavičius D. , Meilutytė-Lukauskienė D. , Kriaučiūnienė J. , Šarauskienė D.
Published: October 2019

Uncertainties of runoff projections arise from different sources of origin, such as climate scenarios (RCPs), global climate models (GCMs) and statistical downscaling (SD) methods. Assessment of uncertainties related to the mentioned sources was carried out for selected rivers of Lithuania (Minija, Nevėžis and Šventoji). These rivers reflect conditions of different hydrological regions (western, central and southeastern). Using HBV software, hydrological models were created for river runoff projections in the near (2021–2040) and far (2081–2100) future. The runoff projections according to three RCP scenarios, three GCMs and three SD methods were created. In the Western hydrological region represented by the Minija River, the GCMs were the most dominant uncertainty source (41.0–44.5%) in the runoff projections. Meanwhile, uncertainties of runoff projections from central (Nevėžis River) and southeastern (Šventoji River) regions of Lithuania were related to SD methods and the range of uncertainties fluctuates from 39.4% to 60.9%. In western Lithuania, the main source of rivers' supply is precipitation, where projections highly depend on selected GCMs. The rivers from central and southeastern regions are more sensitive to the SD methods, which not always precisely adjust the meteorological variables from a large grid cell of GCM into catchment scale.
Impacts of land use changes and climate variability on transboundary Hirmand River using SWAT
Authors: Hajihosseini Mohammadreza , Hajihosseini Hamidreza , Morid Saeed , Delavar Majid , Booij Martijn J.
Published: October 2019

Many river basins are facing a reduction of flows which might be attributed to changes in climate and human activities. This issue is very important in transboundary river basins, where already existing conflicts about shared water resources between riparian countries can easily escalate. The decrease of streamflow in the transboundary Hirmand (Helmand) River is one of the main challenges for water resources management in Iran and Afghanistan. This research aims to quantify the causes of this problem which has a direct impact on the dryness of the Hamoun wetlands being an international Ramsar site. To achieve this, the land use changes in the Middle Helmand Basin (MHB) in Afghanistan were evaluated for three time periods between 1990 and 2011 using remote sensing data and the Soil and Water Assessment Tool (SWAT) Model for understanding watershed response to environmental changes. It was concluded that the total irrigated area in the region has increased from 103,000 ha in 1990 to 122,000 ha in 2001 and 167,000 ha in 2011 (62% increase). According to the results, the average annual discharge when adapting the land use during the simulations was 4,787 million cubic meters (MCM)/year and while employing the land use of 1990 from the beginning of the simulations, the average annual discharge was 5,133 MCM/year. Therefore, the agricultural developments in the Helmand basin decreased the discharge with about 346 MCM/year accompanying an increase of 64,000 ha in an irrigated area in MHB after 1990. Notably, the impact of land use change increases significantly for more recent periods and causes a reduction of 810 MCM in annual streamflow for the MHB. The amount of water depletion (i.e. actual evapotranspiration) per hectare has increased from 5,690 in 1985 to 7,320 m3 in 2012. The applied methodology of this study is useful to cope with such a data scarcity region. It can help quantify the impact of land use change on the region and formulates strategies that can improve the situation between Iran and Afghanistan.
Size optimization of a hybrid PV/wind/diesel/battery power system for reverse osmosis desalination
Authors: Xu Daming , Acker Tom , Zhang Xuhui
Published: October 2019

This study was to find the optimal configuration for an independent renewable energy system for reverse osmosis (RO) desalination. The objective was to find the lowest levelized cost of energy (LCOE), with power reliability as the constraint. A genetic algorithm was used to solve the nonlinear integer programming program. A site with brackish groundwater in Arizona, USA was selected. The capacity of the RO system was 18.93 m3/d (5,000 gal/d), requiring a constant power consumption of 3.95 kW. Two scenarios were considered in terms of diesel generator (DG) allowed running time. The results showed that the optimal configuration was a hybrid photovoltaic/wind/diesel/battery system with 0.56 USD/kWh and the corresponding levelized cost of water 3.84 USD/m3, when the DG can run in any hour every day. The optimal solution was a hybrid wind/photovoltaic/battery system with 0.69 USD/kWh and 4.48 USD/m3, when the DG can run between 9 am and 9 pm every day for noise control. Both the two LCOWs were about half of the 7.9 USD/m3 currently paid by residents that live in the area. Sensitivity analyses showed the LCOE was fairly insensitive to photovoltaic panel tilt angle over a range for both the two configurations.