bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress-strain response in gears tooth root due to low cycle fatigue
Authors: Franulovic Marina , Markovic Kristina , Herceg Zdravko
Published: August 2019

Gears are mechanical components which experience high dynamic loading during their exploitation period. Therefore, their load carrying capacity together with life expectancy are often the main research interest in various studies. The research presented in this paper is focused on the materials response in spur gears tooth root, with the attention given to the repeated overloads during gears operation. In order to simulate low cycle fatigue by using numerical modeling of stress - strain relationship within material, the material model which takes into account isotropic and kinematic hardening is used here. Material response of specimens produced out of steel 42CrMo4 in different loading conditions is used for the calibration of material model, which is then applied to simulate damage initiation and materials stress - strain response in gears tooth root. The results show that materials response to the given loading conditions non-linearly change through the loading cycles.
Investigation of the opportunities for experimental research of gear trains vibrations
Authors: Stoyanov Svetlin , Dobrev Vasko , Dobreva Antoaneta
Published: August 2019

The improvement of the dynamic and exploitation characteristics of power transmissions is a significant and important problem. The solution of this problem becomes possible through improving the methods in the area of machine design and the existing approaches in experimental investigations. The vibrations in different technical systems including driving systems and power transmissions increase the noise level and the dynamic load. Therefore, the frequency analysis of these systems is especially important. The theoretical analysis of the dynamic behaviour of gear trains indicates that the vibrations in the area of the resonance zone display non-linear character as a result of partial or complete loss of contact in the meshing. The objective of the research presented is to investigate the dynamic behaviour of gear trains. An experimental test device for measuring, processing and analysis of the gear train vibrations has been deigned. The opportunities for data processing in an environment of LabVIEW and/or MATLAB aiming to obtain in an experimental way relationships demonstrating acceleration and resonant frequencies. Conclusions and recommendations have been summarized.
About waveguide modeling (transmissions of ultrasonic technological machines)
Authors: Krupenin Vitaly , Astashev Vladimir
Published: August 2019

The modeling of energy transfer systems in ultrasonic technological machines is considered. As such systems rod waveguides are usually used. These are, as a rule, distributed systems of variable cross-section, which must transmit energy from an electromechanical vibration exciter to a working body. Sometimes additional equipment is attached to the waveguide (core system), which should be modeled using lumped-parameter subsystems. This article discusses the problems related to the modeling and calculation of the so-called ultrasonic concentrators - waveguides that have a heterogeneous shape and are made to ensure optimal energy delivery to the working body (instrument). Examples of calculations are given that consider the influence of a nonlinear elastic-dissipative load, determined by the nature of the technological process. The analysis of real models is described.
Transmission of lateral vibrations to children during car traveling and possibilities for their reduction
Authors: Pavlov Nikolay , Sokolov Evgeni , Iontchev Emil , Miletiev Rossen , Peychev Mihail
Published: August 2019

The publication addresses the need for technical solutions to reduce the transmission of lateral vibrations to passengers, especially children traveling by car in a child seat. A special design of a pendulum type tilting child seat has been proposed. Results of road trial conducted on a specific mountain road section are shown. The differences in the values of lateral accelerations acting on a child traveling in a conventional and in a tilting seat are given. The power spectral densities of lateral accelerations for both types of child seats are presented and compared. The root mean square values of lateral acceleration are given. Results for the values of the seat tilt angle are presented.
Justification of the parameters of a pneumatic conveyor for active ventilation of soybean during storage
Authors: Duisenova Sholpan , Atykhanov Aibek , Karaivanov Dimitar
Published: August 2019

The article proposes a methodology for studying the productivity (capacity) and power consumption of a pneumatic conveyor for active ventilation of soybeans in container-modular storage in farms and the factors affecting them. In determining the parameters of the pneumatic conveyor, the physical and technological characteristics of the grain (soybean) are taken into account. The proposed methodology is based on the method of classical calculation for selecting a pneumatic conveyor with nominal parameters, which is necessary not only for transportation, both vertically and horizontally, but also for active ventilation of grain in containers during storage. The purpose of the methodology is to select a specific pneumatic conveyor for container-modular equipment for soybeans storage in the conditions of farms in Kazakhstan.
Application of powder filter materials in run-in of engines
Authors: Ilyushchanka Aliaksandar , Kaptsevich Vyacheslav , Korneeva Valeria , Kusin Ruslan , Zakreuski Igar , Charniak Iryna , Kusin Alexey
Published: August 2019

The article discusses the use of powder filter materials (PFM) for cleaning engine oil when running-in internal combustion engines (ICE) of agricultural vehicles at motor repair enterprises. The results of comparative tests of powder, paper and net filter elements (FE) are presented. The design of the equipment for cleaning engine oil during and after run-in the engine is proposed.
Instrumental methods in the diagnostics of special vehicle drive
Authors: Stodola Jiri , Krobot Zdenek
Published: August 2019

The article deals with selected possibilities of diagnostics of the integrated power pack of special vehicles using advanced instrumental tribotechnical diagnostic methods. Fourier Transformation Infrared Spectrometry (FTIR), Ferrography, Atomic Emission Spectrometry (AES) and Laser Counter and Laser-Net Fines were used to analyse used oil samples. The analyses were focused on objective evaluation of the technical state of the monitored systems as well as the degree of degradation of the oils used in these systems.
A topology of grid connected photovoltaic inverter with variable power factor
Authors: Mirev Andrey , Rakanov Yovko , Javorova Juliana , Andonov Anton
Published: August 2019

By outlying renewable energy sources, the reactive electric power of local consumers at the same area must be carried by the grid. This loads and causes losses in the same grid. This can be avoided if the necessary reactive power is generated on the spot by the inverter. For that purpose is proposed and investigated a new modified topology for operating with variable power factor. Features of this topology are: transformerless connection to single-phase grid, symmetrical operation in both half waves and the presence of flying inductor, which eliminate the necessity from a separate boost converter, if the input voltage is smaller than the grid peak voltage. The simulation analysis is done on the model elaborated on the SIMETRIX software environment. The results show that the suggested topology can operate with variable power factor and has many additional advantages.
Nonlinear inversion method based on dynamics model modification
Authors: Zhang Faping , Wu Kai
Published: August 2019

In the fields of modern aviation system, subgrade vehicle system and complex mechanical system, there is a problem that parameters of most dynamic models are inaccurate. This problem results in a large difference between the model results and the experimental results. In order to solve this problem, this paper build a nonlinear inversion method based on dynamics model modification (NIDM). Firstly, the error relationship was obtained by integrating the experimental data with the simulation results of the forward modelling model by the cost function and penalty function. Then, the problem of error function minimization was solved by using the parameter iteration generated by particle swarm optimization algorithm, and the corrected parameters of the forward modelling model were obtained. Finally, the method was tested by building a vehicle suspension vibration model and a pavement excitation model as test samples. The test results show that the fitting degree between the simulation results and the experimental results can be effectively improved by modifying the parameters of the dynamic model based on the NIDM method.
Research on Multi - axis Machining of Titanium Alloy Integral Impeller
Authors: Li Guowei
Published: August 2019

Titanium alloy impeller is hard in material, with large curvature and complex shape, all these factors increase its manufacturing difficulty and machining cost. By formulating the corresponding process plan, the three-axis and five-axis NC machining are combined, and the phased processing mode is implemented. The cutting tools of different lengths are selected according to the needs, and the reasonable processing strategy and cutting parameters are selected. The experimental results show that the processing time of the titanium alloy impeller is reduced effectively, the cost of manufacturing is reduced, and the processing quality is improved.
Dynamic response of a cracked rotor-bearing-seal system
Authors: Zhiwei Huang
Published: August 2019

With the structural parameters of the rotation machinery increased, the seal fluid induced force imposed on the rotor will significantly increase. Taking a cracked rotor-bearing-seal system as object the non-linear dynamic behaviours of the coupled system are investigated using numerical integration method. For the crack in shaft, the segmented switch function is applied to express the process of the crack’s opening and closing in rotation, and the cross stiffness originated from crack is considered. Various nonlinear phenomena compressing periodic, quasi-periodic and chaotic motions in the rotor system are analysed. The research results show that the unstable form of the rotor system is Hopf bifurcation when the crack depth is smaller. The influence to the response of the system increased along with the crack depth, the unstable form of the coupled system is period-doubling bifurcation. The seal clearance has an important impact on stability of the cracked rotor system. In other words, the fluid induced force can reduce the periodic responses of the rotor. It is indicated that this study can contribution to a further understanding of the nonlinear of such a rotor-bearing system with crack and seal.
Solving acoustic scattering problem by the meshless method based on radial basis function
Authors: Liu Weifang , Zhao Sanfei , Zhang Cong , Qiao Huipo
Published: August 2019

In this paper, radial point collocation method (RPCM) is introduced to solve the acoustic scattering problem. This is a mathematically simple, easy-to-program and truly meshless method, which has been successfully applied to solve the solid mechanics and convection diffusion problems. However, application of this method to investigate acoustic problems, in particle the acoustic scattering problem is relatively new. The main advantage of this method is its mathematically simple, easy to program, and truly meshless. A Hermite-type interpolation method is employed to improve the solution accuracy while the Neumann boundary conditions exist. In addition, acoustic scattering problem is a typical unbounded domain problem, in order to solve it with RPCM, the domain is truncated to a finite region and an artificial boundary condition (ABC) is imposed. Finally, numerical example is presented to validate the accuracy and effectiveness of RPCM. In the future, the extension of RPCM to more complex and practical problems, especially the three-dimensional situations need to be investigated in more detail.
Dynamics Analysis of Mooring Near Space Airship with Nosecone Constraint
Authors: Baogang Geng , Yongdong Zhang , Xiaojun Meng , Kai Guo , Hu Ye , Yunfei Li , Jianglong Zhou , Yuan Liu
Published: August 2019

The near space airships usually have a large volume. when the airship leave the boathouse, it is influenced by the near surface wind significantly, and the attitude of the airship will change, and the risk of the experiment will be increase. In this paper, the dynamics method is used to analyse the force in the mooring rope and the attitude of the airship with nosecone constraint. The kinetic equation is established. A typical near space airship is choose as an example. The Runge- Kutta method is used to solve the dynamic equation. According to calculation result, the change law of the force in the mooring rope and the attitude of the airship is given, which can provide reference for the near space airship experiment. For the airport in this paper, the force in the mooring rope near the tail in the windward side is bigger than the others. The stronger rope should be used in design.
Study on Three-Dimensional Analysis Method of Radiation Dose of GEO Satellite
Authors: Xu Chunsheng , Zhang Yang , Liu Hui , Yang Yong , Xia Yongquan
Published: August 2019

GEO satellite in orbit is greatly affected by the total radiation dose of space environment. In order to meet the requirements of satellite reliability design, radiation dose analysis is an important work in the process of satellite design. Previous radiation dose analysis is based on one-dimensional dose-depth analysis, or three-dimensional analysis, but over-simplified 3-D model may cause the analysis results deviated different from the reality. This paper presents a three-dimensional radiation dose analysis method based on the actual 3-D model of satellite. This method could analyze radiation dose with actual models, which could be automatically simplified according to needs. It could automatically extract the attribute information in the model and calculate the radiation dose value in each subspace
Circulating CTRP6 Levels are Increased in Overweight or Obese Chinese Individuals and Associated with Insulin Resistance Parameters: A Pilot Study
Authors: Liao Xin , Liu Sha , Tang Xuejiao , Yang Dan , Liu Hua , Gao Lin , Yang Gangyi
Published: August 2019

Aims CTRP6, a newly discovered adipokine, has been found to be a regulator for energy homeostasis. However, the association between circulating CTRP6 and obesity in humans is still unclear.

Methods 256 individuals, including 185 overweight/obese (OW/OB) and 71 normal weight adults, were recruited for this study. Circulating concentrations of CTRP6 and adiponectin (Adipoq) were examined by ELISA.

Results Serum CTRP6 levels in obese individuals were significantly increased compared with those in healthy individuals (506.1±134.9 vs.363.3±80.5 ng/mL, P<0.01). Conversely, serum Adipoq concentrations in OW/OB individuals were markedly decreased compared with healthy controls [20.8 (12.1–29.3) vs. 14.1
(
8.61–17.7)
;

P<0.01]. Correlation analysis revealed that there was a positive relationship between circulating CTRP6 and age, BMI, Fat%, LDL-C, TG, WHR, TC, FBG, FIns, HOMA-IR and HbA1c, but there was an inverse correlation with Adipoq and HDL-C. Logistic regression analysis revealed that high serum CTRP6 levels are markedly associated with OW/OB. Finally, ROC curve analysis showed that the cut-off value for serum CTRP6 for prediction of IR is 518 ng/mL.

Conclusions CTRP6 may be a marker related to OW/OB.
Der Lipödemschmerz, seine Folgen auf die Lebensqualität
betroffener Patientinnen – Ergebnisse einer Patientenbefragung mittels
Schmerzfragebogen
Authors: Gensior Matthias H.L. , Cornely Manuel
Published: August 2019

Bei 640 Patientinnen einer Fachklinik für operative Lymphologie erfolgte mittels
Fragebogen der Deutschen Schmerzgesellschaft e. V. eine Befragung. Neben Fragen
zum Schmerz und zur Schmerzcharakteristik wurden gleichzeitig noch
demographische Daten miterhoben. Es ergab sich, dass nur bei etwas über 50 %
eine echte Adipositas nachgewiesen werden konnte.Lipödem und Adipositas müssen
als unabhängige Krankheitsbilder gewertet werden. Der Schmerz wurde überwiegend
als drückend und ziehend empfunden. Attribute wie klopfend oder pochend, passend
zu einer akuten Entzündung, erfuhr die Wertung „nichtzutreffend“. Die
Beschwerdesymptomatik war unabhängig vom BMI, der bei der Lipohyperplasie
dolorosa nur bedingt verwertbar ist. Insgesamt ist das Leitsymptom „Schmerz“
sehr facettenreich, das angeborene, nicht erworbene Lipödemfett der Extremitäten
führt zu einer deutlichen Beeinträchtigung der Aktivitäten allgemein, als auch
im Freizeitbereich. Die durch den GBA initiierte Studie muss daher kritisch
gesehen werden. Da bislang keine objektivierbaren Befunde beim Lipödem erhoben
werden können, ist eine subtile Befragung betroffener Patientinnen zur
Diagnosestellung notwendig.
Transanale totale mesorektale Exzision – Voraussetzungen zur sicheren Implementierung
Authors: Kneist Werner
Published: August 2019

Die transanale totale mesorektale Exzision (TaTME) ist eine innovative und technisch anspruchsvolle Methode zur chirurgischen Behandlung des Rektumkarzinoms. Ziel dieses Artikels ist es, die Voraussetzungen und Trainingsbedingungen darzustellen, die für die sichere Implementierung dieses komplexen Verfahrens entscheidend sind. Die internationalen Expertenmeinungen werden vor dem Hintergrund der veröffentlichten Ergebnisse aus TaTME-Schulungszentren diskutiert. Darüber hinaus werden eigene Erfahrungen aus den TaTME-Anatomiekursen (Video) und einer ersten klinischen Serie von 102 TaTMEs mitgeteilt. Das Verfahren sollte in erster Linie von kolorektal spezialisierten Fachärzten für Chirurgie durchgeführt werden. Zunächst ist aber ein strukturiertes Schulungsprogramm an ausgewiesenen Aus- und Weiterbildungszentren obligatorisch. Ein Training am Körperspender und ein Proctoring für die ersten klinischen Fälle sind für eine sichere Implementierung der TaTME erforderlich. Die TaTME-Schulungskonzepte müssen weiterhin validiert werden. Die statistischen Auswertungen erster Fallserien deuten auf Lernphasen hin, die mindestens 40 Operationen umfassen. Hiernach werden niedrigere Komplikationsraten und eine akzeptable TME-Qualität erreicht. Auch in vorliegender Fallserie nahm die Morbidität nach > 40 Fällen signifikant ab (Clavien-Dindo ≥ III: 29 vs. 9%). Die Indikation wird bei besonders hohem Risiko (Median: 6 Risikofaktoren, Streubreite: 4 – 8) für ungenügende TME-Qualität und kritisch eingeschränkte Funktionalität gestellt. Für High-Volume-Zentren mit einer Konzentration von entsprechend selektierten Patienten wird eine TaTME-Frequenz von 20 pro Jahr empfohlen. Strukturierte Schulungsprogramme für TaTME sind notwendig und sollen vor der Einführung in die Klinik durchlaufen werden. Der Case-Volume-Effekt und die individualisierte Indikation führen zur Konzentration der Methode an spezialisierten Zentren.
Safety and Efficacy of Placenta-Derived Mesenchymal Stem Cell Treatment for Diabetic Patients with Critical Limb Ischemia: A Pilot Study
Authors: Wang Jiao , Zeng Xiang-Xia , Cai Wei , Han Zhi-Bo , Zhu Ling-Yan , Liu Jian-Ying , Xu Ji-Xiong
Published: August 2019

Aim Diabetic foot has become the main cause of non-traumatic amputation. Stem cell therapy, especially mesenchymal stem cells (MSCs), holds a great promise as a therapy for diabetic foot with ischemia limb arterial disease. The aim of this pilot study is to evaluate the safety and efficacy of placenta-derived MSCs (P-MSCs) treatment for diabetic patients with critical limb ischemia (CLI).

Methods Four eligible diabetic patients with CLI were consecutively enrolled in this pilot study. On the base of the standard-of-care treatment, these patients accepted P-MSCs treatment by intramuscular injection for successive 3 times at an interval of 4 weeks, and the safety and efficacy of placenta-derived MSCs (P-MSCs) treatment were evaluated.

Results There were no serious adverse events during the period of P-MSCs injection and the 24-weeks follow-up period. The clinical ischemic features of patients were improved 24 weeks after P-MSCs treatment. The scores of resting pain and limb coldness significantly decreased, and pain-free walking distance significantly increased from baseline to 24 weeks after P-MSCs therapy. The resting ankle brachial index increased, but no statistically significant difference was found. The findings of magnetic resonance angiography showed the increase of collateral vessel formation in one patient, but there were no significant changes observed in the other patients.

Conclusions The data in this pilot study indicated that multiple intramuscular P-MSCs injections may be a safe and effective alternative therapy for diabetic patients with CLI, and larger, placebo-controlled, perspective studies are needed to prove these results.
Synthesis of Tetrahydropyrazolo[4',3':5,6]pyrano[3,4-c]quinolones by Domino Knoevenagel/Hetero Diels–Alder Reactions
Authors: Kiamehr Mostafa , Mohammadkhani Leyla , Khodabakhshi Mohammad Reza , Jafari Behzad , Langer Peter
Published: August 2019

An efficient Lewis acid mediated domino Knoevenagel/hetero Diels–Alder (DKHDA) reaction of pyrazolone derivatives with N-acrylated anthranilic aldehydes was developed, which afforded functionalized tetracyclic tetrahydropyrazolo[4',3':5,6]pyrano[3,4-c]quinolones. The products were formed in good yields and with excellent regio- and stereoselectivity in favor of the cis-configured isomer.
All I Have Learned, I Have Learned from Google: Why Today's Facial Rejuvenation Patients are Prone to Misinformation, and the Steps We can take to Contend with Unreliable Information
Authors: Mehta Neil , Gupta Amar , Nissan Michael
Published: August 2019

A growing number of patients are seeking answers for their health concerns online. This study assesses the reliability, quality, and readability of online materials patients have access to through the Internet and evaluates the social media presence of information providers. An online search was conducted for facial rejuvenation by utilizing three ubiquitously used web search engines: Google, Bing, and Yahoo. The first 25 result pages were collected from each search engine, and exclusionary criteria were applied to exclude online stores and advertisements. Website reliability and quality were assessed via the DISCERN method. Readability was measured through six measurements: Flesch–Kincaid Grade Level (FKGL), Gunning Fox score, SMOG index, Coleman Liau index, and automated readability index. Social media presence and profile followers on Facebook, Twitter, and Instagram were determined to gauge social media presence. Exclusionary criteria yielded 41 unique websites, with the majority of websites authored by physicians (54%) followed by professional organizations (19%). The DISCERN method demonstrated that journal websites yielded the highest overall quality (4.00) and physician websites yielded the lowest (2.72). Readability analysis demonstrated that online forums proved the most challenging to read, and encyclopedia articles were the least challenging. Physician websites maintained the highest social media presence (95%) followed by professional organizations (75%). However, professional organizations had more social media followers in comparison to physician websites. Physician websites and professional organizations overwhelmingly command social media presence compared to other information providers and provide information with serious deficits in reliability and quality. A strong majority of online information also surpasses the health care literacy of patients. This poses a serious concern for physicians who need to provide and guide patients to high quality and reliable information.
Ultrasound to Localize the Peripherally Inserted Central Catheter Tip Position in Newborn Infants
Authors: Ren Xiao-Ling , Li Hong-Lei , Liu Jing , Chen Ya-Juan , Wang Man , Qiu Ru-Xin
Published: August 2019

Objective This study aimed to evaluate the application of ultrasound for the localization of the tip position of peripherally inserted central catheters (PICCs) in newborn infants.

Study Design This study was a retrospective analysis on ultrasonic localization for PICC placement conducted in our department over the past 2 years. Ultrasonic localization was performed immediately after PICC placement in all neonatal patients. Successful PICC placement was confirmed if the PICC tip position was located at the inferior/superior cavoatrial junction. Chest X-ray localization was performed on 32 infants immediately after ultrasound examination to compare the accuracy of ultrasound localization.

Results Of the 186 patients, 174 (93.5%) had successful PICC placement on the first attempt. In 11 (5.9%) patients, the catheter tip was placed beyond the ideal location as follows: too deep (in the right atrium) in 4 patients, too shallow in 4 patients, and malpositioned in 3 patients. Both the sensitivity and the specificity of ultrasound for identifying PICC tip localization were 100%. Complications occurred in 2.7% of this group of patients.

Conclusion Ultrasonic localization of the PICC tip position is a timely, accurate, and reliable method and can identify the catheter tip with high accuracy. This method could be widely applied in neonatal wards.
Energiespar-Contracting: Win-win-Partnerschaft für die Umwelt
Authors: Kucera Martin
Published: August 2019

Die Universitätsmedizin Magdeburg setzt seit diesem Jahr auf ein neues Konzept zur Energieoptimierung im Rahmen eines sogenannten Energiespar-Contractings. Trotz umfangreicher Investitionen des Contracting-Partners fallen für den Kunden keine Mehrkosten an. Die deutliche Dezimierung der CO2-Emission verbessert auch die Umweltbilanz der Einrichtung.
Calculation of domain wall resistance in magnetic nanowire
Authors: Boonruesi W. , Chureemart J. , Chureemart P.
Published: August 2019

The enhancement of domain wall resistance (DWR) in spintronic devices containing the domain wall is required for a full understanding since it represents the efficiency of spin transport and contributes to magnetoresistance phenomena. In this work, we theoretically investigate the effect of the domain wall width, injected current density, and temperature on DWR in magnetic nanowire by using the generalized spin accumulation model based on the Zhang, Levy, and Fert approach. The proposed model allows us to deal with a multilayer system with arbitrary orientation of magnetization. In addition, the temperature effect can be taken into account by considering the spin-dependent resistivity of the ferromagnet at any finite temperature. This leads to the calculation of temperature variation of spin transport parameters, and it eventually allows us to calculate the thermal effect on spin accumulation. The spin transport behavior and DWR can be calculated directly from the gradient of spin accumulation and spin current within the wall. The results show the increase in DWR with temperature as the thermal effect causes the reduction of transport parameters.
Effects of anion size on flow electrification of polycarbonate and polyethylene terephthalate
Authors: Kou Rui , Zhong Ying , Qiao Yu
Published: August 2019

Flow electrification at polymer surfaces has long been studied; yet, its mechanism is still not fully understood. In the current research, we experimentally investigated the surface electric potentials of polycarbonate and polyethylene terephthalate exposed to electrolyte solutions of various anion sizes. The surface potential was always negative, and its magnitude decreased as the anion became larger. Other important factors include the ion concentration and the flow rate. These results help precisely control the polymer charging process, important for electret processing, energy harvesting, biosensing, among others.
Parametric effects in circuit quantum electrodynamics
Authors: Wustmann Waltraut , Shumeiko Vitaly
Published: August 2019

We review recent advances in the research on quantum parametric phenomena in superconducting circuits with Josephson junctions. We discuss physical processes in parametrically driven tunable cavity and outline theoretical foundations for their description. Amplification and frequency conversion are discussed in detail for degenerate and nondegenerate parametric resonance, including quantum noise squeezing and photon entanglement. Experimental advances in this area played decisive role in successful development of quantum limited parametric amplifiers for superconducting quantum information technology. We also discuss nonlinear down-conversion processes and experiments on self-sustained parametric and subharmonic oscillations.
Energy dissipation after single vortex reconnection in He II at different temperatures
Authors: Andryushchenko V. A. , Kondaurova L. P.
Published: August 2019

The dynamics of vortex loops from the moment of reconnection to their collapse are investigated. Numerical studies are carried out within the framework of the vortex filament model at different temperatures and for various sets of initial data. It is shown that at nonzero temperatures, after the moment of reconnection, i.e. in the presence of large perturbations, there is an increased dissipation rate of the total kinetic energy due to the mutual friction force. The nature of the dissipation is universal for all temperatures and initial conditions. The power of dissipation increases with increasing temperature. The vortex impulse modulus decays linearly, starting from the moment of reconnection, and also has a universal shape. For the chosen spatial resolution, a Kelvin-wave cascade is not observed near absolute zero; this phenomenon apparently occurs on a smaller scale. Time dependences of the length of the vortex loops, the average curvature, the minimum distance between the perturbations, are obtained.
Spatiotemporal vortex rings in atomic Bose–Einstein condensates
Authors: Chelpanova O. G. , Kuriatnikov Y. I. , Vilchinskii S. , Yakimenko A. I.
Published: August 2019

We investigate spatiotemporal vortex rings with phase dislocation both in space and time. It is demonstrated that these structures naturally appear as a periodical in time edge phase dislocation at the low-density region of a perturbed atomic Bose–Einstein condensate. The condition of formation, dynamics and stability of the spatiotemporal vortex rings are investigated for repulsive and attractive interatomic interactions. These theoretical findings open up a perspective for experimental observation of novel type of topological coherent structures in ultracold gases.
A dynamical motif comprising the interactions between antigens and CD8 T cells may underlie the outcomes of viral infections
Authors: Baral Subhasish , Antia Rustom , Dixit Narendra M.
Published: August 2019

Significance

Viral infections have different outcomes in different individuals. They could be cleared spontaneously, turn chronic, or cause host death due to tissue damage. Identifying what determines these outcomes has been a longstanding challenge in immunology. Many factors, including viral inoculum size and host genetics, that influence the outcomes have been identified, suggesting that a complex interplay of numerous factors determines the outcomes. In striking contrast, we argue that the outcomes are determined by a dynamical motif comprising a few, essential interactions between viral antigens and CD8 T cells. The other factors influence the outcomes indirectly by modulating these essential interactions. The motif presents a conceptual understanding of the outcomes, explains several confounding experimental observations, and proposes interventions.
DMBT1 suppresses progression of gallbladder carcinoma through PI3K/AKT signaling pathway by targeting PTEN
Authors: Sheng Shen , Jiwen Wang , Dexiang Zhang , Bohao Zheng , Yueqi Wang , Han Liu , Xiaoling Ni , Tao Suo , Liu Houbao
Published: August 2019

Gallbladder carcinoma (GBC) is a highly lethal malignancy of the gastrointestinal tract. Despite extensive research, the underlying molecular mechanism of GBC remains largely unclear. Deleted in malignant brain tumors 1 (DMBT1) is low-expression during cancer progression and as a potential tumor-suppressor gene in various types of cancer. However, its role in Gallbladder cancer remains poorly understood. Here, we found that DMBT1 was significantly low-expression and deletion of copy number in GBC tissues by qRT-PCR and Western blot. Overexpression of DMBT1 impaired survival, promoted apoptosis in GBC cells in vitro, and inhibited tumor progression in vivo. Further study of underlying mechanisms demonstrated that DMBT1 combined with PTEN which could stabilize PTEN protein, resulting in inhibiting the activation of PI3K/AKT signaling pathway. Our study revealed a new sight of DMBT1 as a tumor-suppressor gene on the PI3K/AKT pathway in GBC, which may be a potential therapeutic target for improving treatment.
Highly reliable and selective ethanol sensor based on α-Fe2O3 nanorhombs working in realistic environments*
Authors: Yan Wenjun , Zeng Xiaomin , Liu Huan , Guo Chunwei , Ling Min , Zhou Houpan
Published: August 2019

A highly reliable and selective ethanol gas sensor working in realistic environments based on alpha-Fe2O3 (α-Fe2O3) nanorhombs is developed. The sensor is fabricated by integrating α-Fe2O3 nanorhombs onto a low power microheater based on micro-electro-mechanical systems (MEMS) technology. The α-Fe2O3 nanorhombs, prepared via a solvothermal method, is characterized by transmission electron microscopy (TEM), Raman spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The sensing performances of the α-Fe2O3 sensor to various toxic gases are investigated. The optimum sensing temperature is found to be about 280 °C. The sensor shows excellent selectivity to ethanol. For various ethanol concentrations (1 ppm–20 ppm), the response and recovery times are around 3 s and 15 s at the working temperature of 280 °C, respectively. Specifically, the α-Fe2O3 sensor exhibits a response shift less than 6% to ethanol at 280 °C when the relative humidity (RH) increases from 30% to 70%. The good tolerance to humidity variation makes the sensor suitable for reliable applications in Internet of Things (IoT) in realistic environments. In addition, the sensor shows great long-term repeatability and stability towards ethanol. A possible gas sensing mechanism is proposed.
Finite element modeling and updating of the composite plate structure
Authors: Yaacob R M , Hashim M A H , Sani M S M
Published: August 2019

Composite plate structure is broadly used in engineering structures for automotive and aerospace applications. Furthermore, the problem in vibrational is one of the industries main challenges. Composite materials are frequently used in industry for weight and cost reduction to enhance mechanical properties in structural components. This research aims to execute a composite plate structure model updating procedure. Through finite element analysis (FEA) and experimental modal analysis (EMA), modal parameters such as natural frequencies, mode shapes, and damping ratios are collected. Composite plate structure is set to be free-free boundary condition and node equivalence is done in the surface plate area. Correlation is executed between these two data sets. The discrepancies in natural frequencies between FEA and EMA were reduced with the selected parameters identified to perform structure updating model using sensitivity analysis.
Updating of the Dynamic Behaviour of an Assembled Structure with Bolted Joints in Light of EMA Results
Authors: Omar R , Rani M N Abdul , Yunus M A , Isa A A M , Rahman Z A
Published: August 2019

Bolted joints, which contribute significantly to minimise the magnitudes of resonant peaks of assembled structures and give easy-to-install and uninstall, have been widely used in various types of mechanical structural assembly and. However, modelling of an individual bolted joint within a large assembled structure has always been problematic, especially when it comes to predicting dynamic behaviour. The aim of this paper is to put forward an idea of efficiently and economically modelling of bolted joints of an assembled structure focusing on the bolting and assembly interfaces. The finite element (FE) models of individual components (Plate A and Plate B), bolting and assembly interfaces were developed using the NX11 Simcenter 3D software. Normal modes analysis was carried out for the initial FE models of the individual components and the assembled structure. Experimental modal analysis (EMA) was performed to determine the modal parameters of the individual components and assembled the structure. It was found that a low correlation between the initial FE models and EMA has been recorded. The initial FE models were then tuned in the light of EMA results in order to improve their accuracy and reliability. The proposed updating procedure has been successfully used in improving the low correlation which is largely due to the inaccurate modelling of the bolted joints.
Removal of Dust from the Solar Panel Surface using Mechanical Vibrator
Authors: Attia Osam H. , Adam Nor Mariah , As’arry Azizan , Md Rezali Khairil Anas
Published: August 2019

Soiling and its effect on the performance of solar modules are generally of high concern for regions with a high deposition of dust and low frequency and less intensity of rainfall. The procedure of removing dust using traditional methods is capital and labour intensive. Additionally, most of the cleaning methods consumed power from the energy produced by the solar system. Therefore, the main objective of this study is to investigate the effect of vibration magnitude on the dust removal index of solar panel. In this work, wind energy was transformed into mechanical energy i.e. vibration. The mechanical vibrator attached to a panel produced harmonic excitation force to overcome the adhesive force between the dust particles and the surface of the solar panel. The generated vibration force has a linear relationship with the air velocity. This new designed and fabricated system was able to remove 3.5 gram of dust out of 5 grams on the panel with a vibration force of 3.128 N at a tilt angle of 15°. The new system has effectively proven that wind energy if being converted into vibration force can be used for dust removal from the solar panel surface.
Biodynamic Modelling of Hand for Glove Transmissibility Prediction using Artificial Neural Networks
Authors: Rahman Tuan A Z , Rezali K A M , As’arry A , Jalil N A A
Published: August 2019

Prediction of glove transmissibility to the hand plays an important role in order to improve its vibration reduction capability. This study presents a non-parametric biodynamic modelling of the hand based on artificial neural networks (ANNs) model for predicting the apparent mass in order to estimate the transmissibility of a glove to the hand. An experimental investigation was carried out to obtain the input-output vibration data using five subjects. Then, an ANNs model was used to map between the input and the output with its weight and bias parameters optimized using chaos-enhanced stochastic fractal search (CFS) algorithm. The results indicate that the developed ANNs hand model capable to predict the apparent mass of the human hand with an average accuracy of 97.67%.
Application of the Structural Dynamic Modification Method to Reduce the Vibration of the Vehicle HVAC System
Authors: Satar MHA , Mazlan AZA , Hamdan MH , Md Isa MS , Man S , Paiman MAR , Abd Ghapar MZ , Sulaiman MSA
Published: August 2019

Heating, ventilating and air conditioning (HVAC) system is one of the major sources for the vehicle noise and vibration, which subsequently contribute to the bad acoustical environment. The components of the HVAC system can produce a significant level of vibration during the operation and contributed to an unwanted noise. As the vibration of HVAC components get worse, it will be transferred to other components and excites the natural frequencies of the HVAC system. Natural frequencies of the components are depending on the mass and stiffness of the HVAC components and the value can been modify using these two parameters. This study is focusing on the specific type of HVAC noise and vibration problem and the counter measure has been perform by implementing the structural dynamic modification (SDM) method to the air conditioning (AC) pipe. The lab-scale of the vehicle HVAC system is set up to represent the actual HVAC system with the real vehicle operation. Noise and vibration of the HVAC system in the system level are measured and compared. From this data, the Dynamic Vibration Absorber (DVA) is designed and applied at the AC pipe of the HVAC system. The result shows that, the natural frequency of the AC pipe can be shifted which resulting a wide effective frequency range of 100-500 Hz. The effect of DVA on the HVAC system is observed during operation whereby a significant vibration attenuation has been achieved for operating frequency range of 100-300 Hz.
Effect of flattening reduction rate of primary recrystallization microstructure and rare earth in copper-containing grain-oriented silicon steel on secondary recrystallization
Authors: Jin Zi-li , Ren Hui-ping , Zhang Zhi-nan , Wu Zhong-wang
Published: August 2019

The results show that the content of rare earth and the flattening reduction rate after the initial recrystallization annealing have significant effects on the secondary recrystallization process and grain growth behavior in the copper oriented silicon steel produced by the first cold rolling method. After the initial recrystallization of the oriented silicon steel containing copper, the flattening with a reduction ratio of about 9%, relatively coarse recrystallized grains are obtained after high temperature annealing. About 8 ppm of lanthanum and 3 ppm of cerium were added to the oriented silicon steel containing copper, the temperature at which the secondary recrystallization abnormally grew during the high temperature annealing was increased by 30 °C ∼50 °C . After the primary recrystallization annealing, the secondary recrystallized structure of copper-oriented silicon steel containing rare earth is relatively coarse after being flattened.
Cold Rolling Reduction Dependence of the Recrystallization Texture of 3% Si Non-oriented Electrical Steel
Authors: Seil Lee , De Cooman Burno C.
Published: August 2019

The effect of the amount of cold reduction on the crystallographic texture, the microstructure, and the magnetic properties of cold rolled and annealed 3% Si non-oriented (NO) Si steel has been studied. The results indicate that, at constant final thickness, the combination of initial hot-rolled sheet thickness and the cold rolling reduction had a significant influence on the B50 magnetic flux density. The initial thickness of the hot-rolled sheet did not affect the crystallographic texture of the as-hot rolled sheet and the annealed hot-rolled sheet. At constant final thickness, the combination of a larger hot-rolled sheet thickness and a higher cold rolling reduction resulted in the decrease of the B50 magnetic flux density. This was due to an increase of the {411}<148> and {111}<112> texture components intensity and a decrease of the {110}<001> texture component intensity.
Evolution of recrystallization texture in non-oriented electrical steels during final annealing – influence of shear stress after cold rolling
Authors: Bacroix B , Schneider J , Franke A
Published: August 2019

The fabrication process of non-oriented electrical steels comprises hot rolling, annealing of the hot band (optional), cold rolling and final annealing. Starting from different hot band, quite distinct deformation substructures have been observed after cold rolling of ferritic FeSi steels. The recrystallization texture after annealing of the cold rolled material depends on the deformation structure obtained after cold rolling. In the present paper, a simple method to evaluate the energy stored during cold deformation of Fe-Si steels is presented. An estimate of the stored energy has then been made for various deformation modes (in-plane compression superimposed with shear stress). It is shown that, by adding a shear component, a more appropriate explanation of the experimental observed recrystallization textures may be obtained. The existence of shear components produces an inversion of the soft and hard orientations with respect to the case of a pure in-plane strain compression.
Effect of pearlite morphology on recrystallization behaviour in cold rolled high strength automotive steel sheets
Authors: Janakiram S , Gautam J , Kestens L A I
Published: August 2019

The present study is mainly focused on recrystallization behaviour and associated microstructure and texture evolution with the effect of second phase as pearlite. Two cold rolled sheets with 80% cold reduction consisted of coarse and fine pearlite bands along with ferrite. Cold rolling was followed by interrupted annealing at different soaking time to study the kinetics and recrystallization texture evolution. Results are analysed with the help of micro-Vickers hardness, microstructure and texture analysis through SEM and Electron Backscattered Diffraction (EBSD). Results clearly show the effect of pearlite band size on recrystallization kinetics and texture evolution. Faster recrystallization is observed for fine pearlite band compared to coarse band. Heterogeneous nucleation of grains took place at ferrite pearlite interface, grain boundaries of RD-ND orientations and within the deformed ferrite. Fragmentation and spherodization of pearlite lamellae takes place inside the colony of pearlite with increase in soaking time.
Microstructure, texture, and mechanical behaviour of warm-rolled and annealed standard duplex stainless steel
Authors: Dias F L , Tavares T B , Santos D B
Published: August 2019

The microstructural evolution and mechanical behaviour of 2205-type duplex stainless steel were studied after plate warm rolling at 600 °C with 60% and 80% thickness reduction and subsequently annealed at 1050 °C for 300 s. With increasing thickness reduction level, ferrite-phase α-fibre became weaker and γ-fibre was developed. For the austenite phase, a weakening of Brass component and increases in Goss and Copper components was observed. A transition from bamboo type into a pearl structure from the 60% sample to the 80% warm-rolled annealed sample was observed. An average tensile strength of 794 MPa was assessed through tensile tests. Post deformation tests demonstrated an increase in microhardness toward the fractured areas and a deformation-induced martensitic transformation was observed in transmission electron microscope results in those regions for all conditions.