bluuebunny/crossref_metadata_2025 huggingface dataset:
Element composition of additive products from electroerozive cobalt-chromum powders
Authors: Ageev Evgeny , Altukhov Alexandr , Novikov Alexandr
Published: October 2018

The wide use of the EED method for processing metal waste into powders for the purpose of their reuse and application in additive technologies is hampered by the lack in the scientific and technical literature of full-fledged information on the effect of the initial composition, regimes and media on the properties of powders and technologies of practical application. Therefore, in order to develop technologies for the reuse of electroerosive powders and to evaluate the effectiveness of their use, complex theoretical and experimental studies are required. The aim of the work was to conduct X-ray spectral microanalysis of additive products from electroerosive cobalt-chrome powders. For the implementation of the planned studies, wastes of the cobaltochrome alloy of the brand KHMS “CELLIT” were chosen. As a working fluid, butyl alcohol (butanol-1) was used. For the production of cobalt-chrome powders, a unit for EED of conductive materials was used. Dispersion parameters: voltage 100 V, capacity 48 μF, repetition rate 120 Hz. The microstructure of the samples (on the surface) was studied by scanning electron microscopy. The surface of the samples was ground and polished. With the help of an energy-dispersive X-ray analyzer from EDAX, built into the scanning electron microscope QUANTA 200 3D, spectra of characteristic X-ray radiation were obtained at various points on the surface of the sample and along the cross-section. Based on the results of X-ray spectral analysis of additive products from electroerosive cobalt-chrome powders, it has been established experimentally that the main elements in them are Co, Mo, and Cr.
Analysis of mathematical models of drilling describing surface quality and tool overload protection aspects
Authors: Abdulgazis Dilyaver , Umerov Ervin , Abdulgazis Umer
Published: October 2018

In the article, taking into account the specifics of the drilling operation, especially deep, the analysis of the known mathematical models describing the aspects of ensuring the accuracy and quality of the holes is presented. Based on the results of the analysis of the known mathematical models, it is concluded that the available dependences cover only part of the problem of improving the accuracy, aging the shape of the hole and the quality of its surface. The expediency of development of mathematical models more widely covering technological systems of drilling of holes, especially in difficult materials is shown. An example of the work of the system of stabilization of the load on the drill, where the correction of adjustable values is carried out by the current drilling depth.
Optimization of the parameters of the piston pin bearing of the tractor engine taking into account the solution of the lubrication problem
Authors: Zavyalov Oleg
Published: October 2018

The task of the investigation is to make the model, the algorithm, the program and the results of the calculations of optimization of the parameters of the bearing sliding of piston pin of the internal-combustion engine. An approximate mathematical model of dynamically loaded bearings of a piston pin of the internal-combustion engine was built up with the account of calculation methods of the statically loaded sliding bearings. The approximate mathematical model describes the relationship of output parameters of bearings of piston pin the operational and structural factors. The model is based on the method of M.V..Korovchinskiy of hydrodynamic calculation of statically loaded sliding bearings. The solution of optimization task was performed with the help of the author’s program in MATLAB environment. The optimization was produced by using the gradient release method. At each iteration a step was calculated in the condition of minimum of the function of the independent variable. The program of the calculation is a finished product and it can be used at the designing of the bearings of sliding engines.
Systematization of the definitions characterizing the content of services provided by industrial enterprises
Authors: Revenko Nikolay , Berkutova Tatyana , Silivanova Olga
Published: October 2018

The conducted analysis of the conceptual construct applied in scientific literature to reveal the relationships characterizing the content of the processes of produced equipment maintenance and repair, as complication of technical means, caused by the acceleration of scientific and technical progress, changes requirements for organization of processes of operation, and significantly changes the situation in the relationships between a producer and a consumer at which the priority in economic interests reserves for a consumer. These circumstances could justify the main motivation to create the necessary conditions to develop the service providing the consumer a possibility of optimum alternating choice while buying and using goods, and, in particular, technical and industrial goods. In the market, the crucial factors to buy those goods are to a lesser extend their price and technical operational characteristics than the real ability of the enterprises to provide necessary maintenance and repair during all operation life.The attempt is made to differentiate definitions in relation to technical and industrial goods, cultural goods and household goods. It is offered to define the services connected with satisfaction of human needs as “service, service maintenance”, and to define the services, connected with creation of material assets, as «production service».
Using business process improvement concept to optimize enterprise production system in conditions of innovative economic development
Authors: Palkina Elena S.
Published: October 2018

Innovation is the basis of economic growth. Currently, they are mainly subordinated to the goal of creating a digital economy. The article is devoted to creation of research methodology in the field of production and economic system development processes, real and potential results of its functioning on the basis of the business processes improvement concept that will serve the making managerial decisions, implementation of the innovative scenario of the Russian enterprises strategic development, increase of their competitiveness in the world market.
Experimental research in automobile non-pneumatic tire force heterogeneity
Authors: Mazur Vladimir
Published: October 2018

Simplicity and high efficiency of a wheeled mover as a mechanism for converting rotational motion into a translatory one have conditioned its wide application in overland machines including motor vehicles. However a wheel with a non-pneumatic tyre (NPT) has a sufficient drawback lying in termination of a wheeled machine movement at the excess air pressure loss. Moreover, the loss of excess air pressure in a pneumatic tyre of traditional design at high speed of movement of a motor vehicle can lead to a traffic accident with heavy consequences. The stop of a motor vehicle to change a wheel on a heavy traffic roadway or roadside also poses a threat. These reasons determine the necessity of both well-known design improvements and search for the new wheeled mover design solutions to enhance a motor vehicle safety, the use of wheels with non-pneumatic tyres of elastic polymeric materials being one of them. Safety enhancement by means of non-pneumatic tyre use along with keeping the high performance of wheeled machine operational properties, is an important scientific and technical task that determines the research urgency.
Method of identification of parameters of closed planetary train based on exploratory design
Authors: Kutlubaev Ildar , Matcko Elena , Panfilova Olga
Published: October 2018

Practicability of usage of gears with closed planetary trains in high-powered drives having weight and dimensions limitations is represented. Method that makes it possible to perform evaluation of mass-dimensional characteristics of planetary double-flow gears at the exploratory design stage is proposed. The developed approach makes it possible to determine basic geometric parameters of gear-tooth system: diameters and width of tooth-wheels reasonably. Besides the obligatory fulfillment of contact tooth strength conditions, providing of the required transmission ratio and condition of coincidence of axes of the gear input and output shafts, the condition of its minimum weight and dimensions is taken into account either. The last requirement is achieved by determination of conditional factor that is square of kinematic scheme contour expressed through projected parameters. The minimum value of contour square corresponds to the best combination of diameters and width values of tooth wheels if all functional limitations are maintained. Then the need of arbitrary choice of any of projected parameters and further verification of the choice made at the closing designing stage is excepted. The proposed approach makes it possible to evaluate the efficiency of chosen gear structural scheme at the initial design stage without design study of workpieces and units.
Thermo-ultrasound method for determining the damage of structural material
Authors: Gonchar Alexander , Mishakin Vasily , Kurashkin Konstantin
Published: October 2018

The effect of plastic strain and temperature on the longitudinal and shear waves velocity of austenitic stainless steel 12Kh18N10T (analogue AISI 321) is investigated. Cryogenic corrosion-resistant austenitic steel 12Kh18N10T is interesting due to the fact, that during plastic deformation a martensitic phase is formed. The martensitic phase significantly changes the electromagnetic, elastic and strength properties of the entire material. The formation of a new phase in conjunction with the process of plastic deformation has a significant effect on the temperature dependence of the elastic wave velocity. As a result of the studies, numerical values of the temperature-velocity factor for longitudinal and shear ultrasonic waves in steel 12Kh18N10T were obtained. The relationship between changes of the magnetic phase and temperature-velocity factor is suggested; it can be used for determining the material damage by the ultrasound method.
Static analysis and parameters synthesis of planetary-layshaft transmissions with three power flows
Authors: Salamandra Konstantin
Published: October 2018

The increase in the number of transmission ratios in the vehicles gearboxes leads to an increase in the number of mechanisms used and their complication. One way to obtain simple designs of multi-speed transmissions with smaller number of gears, clutches, brakes and synchronizers is to use combinations of planetary differential gears and gears with fixed axes (planetary-layshaft transmissions). The article presents a static analysis of a planetary-layshaft transmissions with three parallel power flows for obtaining the dependencies between the gear ratios of the internal mechanisms and the speed ratios of the transmission. A technique for determination the gear ratios of the internal mechanisms for providing a close to a given series of transmission ratios is described.
Improving the economic efficiency of Russian industrial enterprises
Authors: Mechikova Maria , Zemlyakova Nataliya , Medjuha Ekaterina
Published: October 2018

This study is devoted to the study of the current state of the industry in Russia, the identification of positive and negative trends in the development of domestic industry, the development of a system of indicators that reflect the effectiveness of individual industrial enterprises, as well as the development of proposals to improve their economic efficiency.
Chaotic dynamics of a pulse modulated control system for a heating unit
Authors: Gol’tsov Yuriy A. , Kizhuk Alexander S. , Rubanov Vasiliy G.
Published: October 2018

The dynamic modes and bifurcations in a pulse control system of a heating unit, the condition of which is described through differential equations with discontinuous right–hand sides, have been studied. It has been shown that the system under research can demonstrate a great variety of nonlinear phenomena and bifurcation transitions, such as quasiperiodicity, multistable behaviour, chaotization of oscillations through a classical period–doubling bifurcations cascade and border–collision bifurcation.
A method of predicting the time of failure of a rolling bearing
Authors: Liakhmanov Dmitry , Gay Vasily , Polyakov Igor
Published: October 2018

This article considers the problem of predicting wear and breakage of machine components using rolling bearings. Any mechanism wears out over time and, accordingly, the risk of breakage increases. This creates the need for timely maintenance of worn out parts of machinery. The solution of the problem consists in the development of new models and methods for predicting the condition of bearings in the nodes and mechanisms. The developed methods, unlike known ones, should allow us to increase the accuracy of the residual resource prediction, working in the absence of accumulated statistics on faults. To solve the problem, it is proposed to use the theory of active perception, which allows solving problems associated with the use of known methods of pattern recognition.
Improving the efficiency of the roller screen with circular disks
Authors: Kondratiev Alexander , Smorodov Sergei , Antsev Vitaliy , Kirichek Andrei
Published: October 2018

The design, operation and technical characteristics of the roller screen test bench with movable aprons are described. The results of studies of gravel screening on a roller device with circular disks are presented. The rational parameters of the roller screen plate are obtained: the speed of the rollers with disks, working surface canting angle, the speed of the aprons. Comparative evaluation of the efficiency and productivity of the screening process at the devices with circular and multisided disks is given.
Technology of computing risks visualization for distributed production infrastructures
Authors: Voronin Dmitrii , Shevchenko Victoria , Chengar Olga
Published: October 2018

Scientific problems related to the classification, assessment, visualization and management of risks in the cloud environments have been considered. The analysis of the state-of-the-art methods, offered for these problems solving, has been carried out taking into account the specificity of the cloud infrastructure oriented on large-scale tasks processing in distributed production infrastructures. Unfortunately, not much of scientific and objective researches had been focused on the developing of effective approaches for cloud risks visualization providing the necessary information to support decision-making in distributed production infrastructures. In order to fill this research gap, this study attempts to propose a risks visualization technique that is based on radar chart implementation for multidimensional data visualization.
Efficiency of cooling the water droplets within Jet-Film unit of cooling tower filler
Authors: Madyshev Ilnur N. , Dmitrieva Oksana S. , Dmitriev Andrey V.
Published: October 2018

Researches of blocks of sprinklers of cooling towers with jet-film devices are presented. The conducted numerical studies allow us to estimate the influence of the design and operating parameters of the proposed contact device on the efficiency of the process of cooling the recycled water. The increase in the average gas velocity leads to a more intense flow of water drops and more efficient cooling. To achieve high performance, it is necessary to create zones of drip interaction of phases with droplet sizes up to 100 µm at relatively low speeds of two-phase gas-liquid flow. Under such conditions, the drop can be cooled by more than 10°C within one contact stage. The proposed sprinkler units with jet-film contact devices will be able to achieve a lower level of cooling water temperatures in the cooling towers of industrial enterprises at relatively low operating costs.
Investigation of the vibration state of the turbine rotor taking into account the influence of geometric accuracy of parts
Authors: Bolotov Michail , Pechenin Vadim , Kolchina Ekaterina
Published: October 2018

The article describes the method of estimating the state of vibration of the rotor taking into account the geometrical deviations parts. The results obtained theoretical studies of the relationship of vibration characteristics and geometrical deviations of the rotor of low pressure turbine. To conduct research, a parametric rotor model has been created, as well as a finite element model in the ANSYS. To determine the center of mass of a part in the process of balancing, an algorithm developed in the program MATLAB.
The robotized stand for the diagnosing compression refrigerating machines
Authors: Petrosov Sergey , Lemeshko Michael , Kozhemyachenko Alexander
Published: October 2018

The process of creation and improvement of small refrigerating machines, the way of increasing their energy efficiency and reducing costs should be provided with reliable means and effective technologies of technical diagnosing these machines. One of the methods for achieving this goal is the creation of robotic research complexes. The authors, using the example of the automated research stand, show a possible variant of solving research problems when the researcher needs to make a measurement program, including a program of varying experimental conditions. Long-term tests with recording measurement results are performed in automatic mode without the operator-researcher’s participation. The robotic stand usually replaces the research operator, and ensures the effective results of long-term studies as they can be carried out more qualitatively and deeply, with simultaneous evaluation of results and adjustments of the measurement plans. The scheme and description of the developed stand are given. The significant advantages of a robotic stand are shown in comparison with the known analogous means of technical diagnostics of small refrigerating machines.
Durability of metal structures under quasi-static load
Authors: Ogorelkov Dmitriy , Mironov Vladimir , Lukashuk Olga
Published: October 2018

Failure of materials and structures is one of unresolved problems of mechanics. This paper offers an approximate approach to assessing durability of products on the basis of a mechanical experiment. The experiment represents the fatigue process as a transition of a plastic material into its brittle state. A simplified physical model – which could be used to build a mathematical model of fatigue process – hangs on a local transition of a plastic material into its brittle state. The calculation methodology includes both an original part on cyclic degradation of material strength and correlations based on experiments and checked by design routines. Two approaches to calculating the durability of a randomly-loaded object are compared: using the equation of cyclic degradation of strength and the rule of linear summation of fatigue damages. The results obtained are useful for improving methodologies of calculating service life or durability of structures.
Mathematical model of the volumetric hydrodrive’s dynamics, sensitive to the loading variation
Authors: Ivanovskaya Alexandra , Popov Vladimir
Published: October 2018

The paper deals with the problems of mathematical modeling of the dynamic processes proceeding in a complex hydromechanical system of the ship’s deck load-lifting devices. The characteristic feature of this class of equipment is the operation in special conditions, i.e, under the influence of external hydrometeorological factors, taking into account variations in the parameters of lifted or lowered cargo. With a view to gradual regulation of the change of torque on the working drum to reduce dynamic loads, it is offered to use a hydraulic drive that is sensitive to the variation of loading. The operating principle of the considered volumetric hydraulic drive is described. The received mathematical model allows to establish influence of the hydrodrive parameters on transients in a drive system.
Modeling of the elastic characteristics of a long-fiber reinforced composite with an arbitrary orientation of the reinforcing fibers
Authors: Pavlov Victor P. , Kudoyarova Vilina M. , Philippov Alexander A.
Published: October 2018

Currently, the question of the best scheme for constructing a mathematical model of a homogeneous anisotropic elastic material equivalent to fiber reinforced plastic composite (FRP) with arbitrary laminate stacking sequence configuration, have been remained open. A new method for the theoretical prediction of anisotropic elastic characteristics of material equivalent to a given FRP is suggested in this paper. Results are obtained for representative volume elemen (RV) which has been cut out in three different ways from FRP. Calculations for a specific FRP have shown that the FRP replacement by a homogeneous anisotropic material equivalent to it leads to an error order 10% for the elastic properties.
Semi-Markov model of a technical system with the component-wise instantly replenished time reserve
Authors: Obzherin Yuriy E. , Sidorov Stanislav M. , Fedorenko Sergey N.
Published: October 2018

Time redundancy is one of the methods to increase the reliability and efficiency of technical systems. When it is used, the system is given additional time (a time reserve) for restoring characteristics. In this paper we construct a semi-Markov model of a two-component system with a component-wise instantly replenished time reserve. In this paper we construct a semi-Markov model of a two-component system with a component-wise instantaneous replenishment of the time reserve. For an approximate determination of the stationary characteristics of the reliability of the system, the phase merging scheme algorithm is used.
Using a parametric 3D assembly of a GTE combustion chamber to quickly generate its computed sector
Authors: Nekhoroshev Maksim , Orlov Mikhail , Ryazanov Aleksandr
Published: October 2018

The paper describes the development of a parametric 3D CAD assembly of a small-size GTD combustion chamber. Based on the chamber model, we derive the internal CAD volume of the designed single-burner sector. The created parametric models are auto-adjustable by an external excel spreadsheet controlling their parameters. The 3D combusion chamber assembly and the single-burner sector can further be used for optimizing the geometry of flame tubes and nozzles, arranging the sustainable fuel burning space, for the spatial distribution of air flows, and for other design tasks.
Eigenvibrations of a simply supported beam with elastically attached load
Authors: Samsonov Anton A. , Solov’ev Sergey I. , Solov’ev Pavel S.
Published: October 2018

The nonlinear differential eigenvalue problem describing eigenvibrations of a simply supported beam with elastically attached load is investigated. The existence of an increasing sequence of positive simple eigenvalues with limit point at infinity is established. To the sequence of eigenvalues, there corresponds a system of normalized eigenfunctions. To illustrate the obtained theoretical results, the initial problem is approximated by the finite difference method on a uniform grid. The accuracy of approximate solutions is studied. Investigations of the present paper can be generalized for the cases of more complicated and important problems on eigenvibrations of plates and shells with elastically attached loads.
Column press design optimization on the basis of stress-strain state’s mathematical modeling
Authors: Karpushkin Sergey , Glebov Aleksey , Karpov Sergey
Published: October 2018

The problem of optimizing the design of vertical column press traverse according to the metal consumption criterion is taken into consideration. As a limitation, the maximum value of equivalent stresses in the volume of the traverse was used. It is shown that the methods of parametric and topological optimization are ineffective for solving the optimization problem. A mathematical model of the stress-strain state of the traverse is proposed, which allows carrying out simulation independently from other elements of the press. The finite element analysis of the existing structure of the traverse revealed the redundancy of the loaded elements amplification, as well as the low manufacturability of the structure. The method of expert analysis was used to find the optimal design. The effect of the thickness of the base of the traverse on the resulting equivalent stresses was studied. A new design of the traverse was proposed on the base of the study results. That design is characterized by low metal capacity and high manufacturability. It is found that the maximum stresses occur in the areas of rapid changes in shape, as well as in the areas of loads.
Development of a technique of the automated construction of 3D models of standard mass transfer trays
Authors: Tukaeva Rimma , Afanasenko Vitalliy , Kulakov Petr
Published: October 2018

The main elements of most mass-transfer columns of industrial enterprises are contact trays which are formed by various details inside the apparatus. The dimensions of the details are standardized and regulated by regulatory documents. under modern conditions of equipment designing it is necessary to develop three-dimensional model of typical assembly units, that is a very time-consuming task. The article considers the way to improve the design efficiency by automation of the process of standard mass-transfer valve tray model development in Kompas 3D system with MySQL application.
Interaction of rotary working body of roller type with the object of processing
Authors: Papusha Sergey K. , Bogus Azamat E. , Konovalov Vladimir I.
Published: October 2018

There was presented the constructive-technological scheme of leaf-separating apparatus for harvesting tobacco leaves in the article. There was conducted the theoretical analysis of the process of tobacco leaf separation from a stalk. There were obtained the dependencies characterizing the trajectory and speed of arbitrary point of the cutting edge of a small drum.
Justification of the design of pneumatic sorting machine for the preparation of selection seeds
Authors: Khamyev Viktor , Gulyev Anatoly , Boiko Andrey
Published: October 2018

The results of the study of the determination of the optimal parameters of the narrowing partitions installed in pneumatic channels with a vertical ascending air flow, intended for seed cleaning, are presented. The installation of the narrowing walls in the pneumatic channels makes it possible to increase the productivity and efficiency of seed cleaning from hardly separated impurities at least 20%, while the optimal ratio of the width of the partitions and the depth of the sections of the air channel varies from 0.3 to 0.5.
Harrowing of sowings with synchronous additional fertilizing
Authors: Serguntsov Alexander , Malashikhin Nikolai
Published: October 2018

There were offered the combination of technological operations for harrowing sowings of different crops at the same time with additional soil mineral fertilizing. On the example of field experience in 2017 in the educational farm “Kuban” of the Kuban State Agrarian University there was tested the effectiveness of various serial production machines for harrowing winter wheat variety Bagrat. In the control plot, harrowing of wheat after wintering was not carried out. The combination of technological operations in one pass of the machine-tractor unit on the field provides a reduction in the fleet of machines, its capital intensity, energy, material costs, and thus the increase the competitiveness of products. As a result of the research, there was offered a new technical support of processes, new working bodies for harrowing, a technological scheme of a multifunctional unit for combining the operations of additional fertilizing and harrowing of sowings, an experimental installation for research, there were studied the working conditions and quality indicators of the various working bodies on harrowing of sowings (uniformity of harrowing depth, structural and aggregate composition of soil after each option treatment of treatment). There was carried out the comparative analysis of the uniformity of harrowing depth of winter wheat crops compared with working bodies in the experiment, there was revealed the advantage of individual serial machines for harrowing crops. Mathematical processing of experimental data confirmed the effectiveness of the rotational harrow-hoe on all qualitative indicators (uniformity of harrowing depth, the coefficient of structural soil, etc.).
Using the imitation model of elementary technological operation at the evaluation of the threshing action of the threshing device
Authors: Fisunova Elena , Lavrenova Tatiana , Zharov Viktor
Published: October 2018

The threshing process consists of a number of elementary technological operations, the duration of each of which proceeds during a time of 0.002-0.004 s. surrounded by one bar. In this article we present the calculation of the parameters of the threshing zone using the law of compression. A model of an elementary technological operation has been developed that makes it possible to determine probability of threshing, Calculate the parameters of the working elements of the output zone of the underdrum space of the threshing apparatus of a combine harvester.
Alexander Gerst forscht für neue Horizonte in Wissenschaft und Technologie
Authors: Schmid Volker , Irina Buchheim Judith
Published: October 2018

Horizons

Autonome Assistenzsysteme mit künstlicher Intelligenz sind heute technisch möglich. Durch solche Assistenten sind Effizienzsteigerungen zu erwarten. Ein solches System mit Sprachsteuerung und Gesichtserkennung soll als Experiment auf der Internationalen Raumstation ISS während der Mission „horizons“ vom deutschen ESA-Astronauten Alexander Gerst getestet werden. Beim Alltag auf der ISS unterliegen die Astronauten 6 Monate durch Isolation und Schwerelosigkeit besonderem Stress. In medizinischer Hinsicht ist dies beim Zusammenspiel zwischen Mensch und Maschine von Interesse sowie die Akzeptanz und mögliche zukünftige Anwendungen. Das Experiment CIMON wurde von Airbus Defence and Space entwickelt und gebaut, im Auftrag des DLR-Raumfahrtmanagements.
Neue Wege gehen – Das Dilemma Führung in Krankenhäusern
Authors: Langhold Andrea
Published: October 2018

Überlastetes Krankenhauspersonal und Investitionsstaus – davon ist nicht nur ein deutschsprachiges Krankenhaus betroffen. Egal ob privat oder kommunal, kaum
ein Haus leidet nicht unter der Spar- und Effizienz-„Geiselhaft“, unter dem Mangel an qualifiziertem Personal und der Notwendigkeit, auf teures Leihpersonal
zuzugreifen. Neben Veränderungen und neuen Strategien muss weiter eingespart werden, oft so lange bis Stationen vorübergehend stillgelegt werden – aus
Personalmangel oder weil kein Geld für Leiharbeitskräfte zur Verfügung steht. Ein Ansatz, um aus dem „was da ist“ etwas zu machen – und das zu bewahren „was
noch da ist“.
Dehydrozingerone Exhibits Synergistic Antifungal Activities in Combination with Dodecanol against Budding Yeast via the Restriction of Multidrug Resistance
Authors: Yamawaki Chika , Yamaguchi Yoshihiro , Ogita Akira , Tanaka Toshio , Fujita Ken-ichi
Published: October 2018

Drug resistance in fungal infections has been a more frequent occurrence with the increasing number of immunocompromised patients. In efforts to overcome the problem of fungal drug resistance, we focused on the phenolic compound dehydrozingerone, which is isolated from Zingiber officinale. The effectiveness of this compound on the model yeast Saccharomyces cerevisiae has not been reported. In our study, dehydrozingerone showed a weak antifungal activity against the yeast, but demonstrated a synergistic effect in combination with dodecanol, which typically only restricts cell growth transiently. Efflux of rhodamine 6G through the multidrug efflux pumps was significantly restricted by dehydrozingerone. The transcription level of PDR5, encoding a primary multidrug efflux pump in S. cerevisiae, was enhanced with dodecanol treatment, whereas the level was reduced by dehydrozingerone. These results suggest that dehydrozingerone may be effective for potentiating antifungal activity of other drugs that are expelled from fungi by multidrug transporters like Pdr5p.
Role of Moderate Hypothermia and Antegrade Cerebral Perfusion during Repair of Type A Aortic Dissection
Authors: McHugh Michael , Conway Brian , Nores Marcos , Stamou Sotiris
Published: October 2018

The goal of this study was to compare early postoperative outcomes and actuarial survival between patients who underwent repair of acute type A aortic dissection with deep or moderate hypothermia.

A total of 132 consecutive patients from a single academic medical center underwent repair of acute type A aortic dissection between January 2000 and June 2014. Of those, 105 patients were repaired under deep hypothermia (< 24 C°), while 27 patients were repaired under moderate hypothermia (≥24 C°). Median ages were 62 years (range: 27–86) and 59 years (range: 35–83) for patients repaired under deep hypothermia compared with patients repaired under moderate hypothermia, respectively (p = 0.451). Major morbidity, operative mortality, and 10-year actuarial survival were compared between groups.

Operative mortality was 17.1 and 7.4% in the deep and moderate hypothermia groups, respectively (p = 0.208). Incidence of permanent stroke was 12.4% in the deep hypothermic circulatory arrest group and 0% in the moderate hypothermia group (p = 0.054). Actuarial 5- and 10-year survival demonstrated a trend for lower long-term mortality with moderate hypothermia compared with deep hypothermia (69% 5-year and 54% 10-year for deep hypothermia vs. 79% 5-year and 10-year for moderate hypothermia, log-rank p = 0.161).

Moderate hypothermia is a safe and efficient alternative to deep hypothermia and may have protective benefits. Stroke rate was lower with moderate hypothermia.
Fibre Interplay in the Pregnant Uterus of the Frugivorous Bat Eidolon Helvum
Authors: Odukoya Samson , Odukoya Opeyemi , Adelodun Stephen
Published: October 2018

Introduction There is currently a lack of adequate information on the mating, reproduction and the reproductive anatomy of the frugivorous bat Eidolon helvum. We, therefore, investigated their uterus during the non-pregnant and pregnant states for adequate information and comparison between the two states to ascertain what histological adaptations occur during pregnancy in relation to collagen and elastic fibers.

Materials and Methods A total of 47 female bats (E. helvum) were used, out of which 24 were pregnant and 23 were not. They were harvested on the Obafemi Awolowo University Campus. The animals were carefully screened, assumed to be presumably healthy and then sacrificed by cervical dislocation. The left and right uterine limbs with the uterine body and part of the placenta were fixed in 10% formal saline, processed for paraffin embedding and sectioned at 5 μm with a rotary microtome. The sections were stained using Verhoeff-van Gieson stain to demonstrate collagen and elastic fibers.

Results The results showed that both uterine limbs were histologically active during pregnancy. The prevalent fiber was the elastic type during the non-pregnant state, and collagen type during pregnancy.

Conclusion We conclude that elastic fibers tend to obey Hooke's law during pregnancy in the uterus of the frugivorous bat E. helvum, which signifies a form of histomorphological response or adaptation to pregnancy in the uterus of this bat species.
Fetal/Neonatal Pericardial Effusion in Down's Syndrome: Case Report and Review of Literature
Authors: Pharande Pramod , Balegar Virupakshappa Kiran , Mehta Bhavesh , Badawi Nadia
Published: October 2018

We report a preterm (35 4/7 weeks) male neonate with Down's syndrome (DS) diagnosed with isolated pericardial effusion (PE) at 20 weeks of gestation. He was born by precipitous delivery, needed no resuscitation and presented within first 24 hours of life with respiratory distress, anemia due to feto-maternal bleed, hypotension, hepatomegaly, and coagulopathy. Postnatal echocardiography confirmed a 5 mm rim of PE without tamponade, normal cardiac structure, and function. He was stabilized with ventilation, packed red cell, fresh frozen plasma, inotropes (dopamine, dobutamine, and adrenaline), and steroid (hydrocortisone). Subsequent evaluation confirmed hypothyroidism, transient myeloproliferative disorder (TMD), hepatic failure due to fibrosis/cirrhosis with portal hypertension, and steroid sensitive hypotension on two occasions possibly due to adrenal insufficiency. PE completely resolved over 2 weeks. In view of progressively worsening liver failure with ascites and portal hypertension, the family opted for palliation. Literature review has been discussed regarding perinatal onset of PE in DS.
Migration of Oxidized Cellulose to the Ventricle as a Complication of Endoscopic Third Ventriculostomy: A Case Report
Authors: da Silva Aldo , Fortes Thiago , Bomfim Rodrigo , Bomfim Filho Ângelo
Published: October 2018

Endoscopic third ventriculostomy (ETV) is an increasingly common neurosurgical procedure. Hemostatic agentes (porcine gelatin and oxidized cellulose) are normally placed to plug the cortical hole after ETV to avoid cerebral spinal fluid leakage, subdural hygroma, and hemorrhage. Here we report the case of a 6-year-old boy with hydrocephalus who underwent ETV and which oxidized cellulose was placed to plug the cortical hole. Magnetic resonance imaging of the head performed 3 months after the procedure showed the presence of oxidized cellulose in the ventricle. After an unsuccessful attempt to remove the cellulose, it was decided that the patient should be kept under observation. Two years later, the child is in good health and without any complaints. Hemostatic agents (especially oxidized cellulose) used on the cortical hole after ETV can migrate to the ventricle and compromise the procedure. Follow-up should be performed for such patients, and the main focus should be on not causing further injury.
Epigenetik der Depression
Authors: Montag C. , Kiefer M. , Sanwald S.
Published: October 2018

Moderne ätiologische Theorien erklären die Entstehung der Major Depression durch eine Interaktion von Genen und Umwelt. Dabei stellt die individuelle Genetik einen Risikooder Resilienzfaktor dar, der im Zusammenspiel mit den individuellen Umweltbedingungen die Depressionsentwicklung begünstigen oder der Entstehung einer Depression vorbeugen kann. Solchen Theorien fehlte bislang das Bindeglied für das Zusammenspiel zwischen Genetik und Umwelteinflüssen. Ein solches Bindeglied ist die Epigenetik, die sich in den letzten Jahren als wegweisend in der Erforschung biologischer Marker stressbedingter Psychopathologie erwiesen hat. Der am besten erforschte epigenetische Mechanismus ist die DNA-Methylierung. Diese hat sich über viele Studien hinweg als ein möglicher Mechanismus etabliert, der dazu imstande ist, die psychopathogene Wirkung von Stress auf behaviorale, endokrine und molekulare Prozesse zu erklären. Diese Arbeit soll dazu dienen, die Grundlagen der Epigenetik und der DNA-Methylierung zu erläutern, um nachfolgend eine Übersicht über die Studienlage zu stress- und depressionsassoziierten Unterschieden in den Methylierungsmustern der bekanntesten Kandidatengene zu geben.
In-plane and out-of-plane free vibration of stepped straight and curved beams with different materials
Authors: Özyiğit Hamdi Alper , Yetmez Mehmet , Uzun Utku
Published: October 2018

This paper presents a comprehensive investigation of the free vibrations of stepped straight and curved beams with different shapes and different materials. The beams are assumed to be Euler-Bernoulli type, and Finite Element Displacement Method (FEDM) is used as a computational approach. In-plane and out-of-plane vibration analyses are handled with stepped straight and curved beams at different end conditions. Material pairs of the stepped curved beam are considered as (i) steel-steel, (ii) steel-aluminum, (iii) steel-brass and (iv) steel-araldite. Results are given in tabular form and compared with those in literature and computations obtained by Ansys. The effects of beam shape and different material type on the vibration characteristics are also investigated.
Efficient design of hardware-enabled reservoir computing in FPGAs
Authors: Penkovsky Bogdan , Larger Laurent , Brunner Daniel
Published: October 2018

In this work, we propose a new approach toward the efficient optimization and implementation of reservoir computing hardware, reducing the required domain-expert knowledge and optimization effort. First, we introduce a self-adapting reservoir input mask to the structure of the data via linear autoencoders. We, therefore, incorporate the advantages of dimensionality reduction and dimensionality expansion achieved by conventional algorithmically-efficient linear algebra procedures of principal component analysis. Second, we employ evolutionary-inspired genetic algorithm techniques resulting in a highly efficient optimization of reservoir dynamics with a dramatically reduced number of evaluations comparing to exhaustive search. We illustrate the method on the so-called single-node reservoir computing architecture, especially suitable for implementation in ultrahigh-speed hardware. The combination of both methods and the resulting reduction of time required for performance optimization of a hardware system establish a strategy toward machine learning hardware capable of self-adaption to optimally solve specific problems. We confirm the validity of those principles building reservoir computing hardware based on a field-programmable gate array.
Temperature controlled Fe/Au/FeRh spin valves
Authors: Dróżdż P. , Ślęzak M. , Matlak K. , Kozioł-Rachwał A. , Wilgocka-Ślęzak D. , Korecki J. , Ślęzak T.
Published: October 2018

We demonstrate that FeRh layers can be implemented to the epitaxial Fe/Au/FeRh spin valve structures grown on MgO(001). Owing to the AFM-FM phase transition in the FeRh film, the magnetic structure of our Fe/Au/FeRh system can be temperature controlled. The indirect exchange coupling between Fe and FeRh films mediated by the Au spacer enables to control the relative orientation of the Fe and FeRh magnetizations by the Au spacer thickness between ferromagnetic and non-collinear with nearly orthogonal magnetizations. Moreover, the evolution of magnetic structure of the Fe/Au/FeRh system along with the AFM-FM transition is accompanied by the reversible in-plane rotation of the top Fe-layer magnetization.
Describing screening in dense ionic fluids with a charge-frustrated Ising model
Authors: Ludwig Nicholas B. , Dasbiswas Kinjal , Talapin Dmitri V. , Vaikuntanathan Suriyanarayanan
Published: October 2018

Charge correlations in dense ionic fluids give rise to novel effects such as long-range screening and colloidal stabilization which are not predicted by the classic Debye–Hückel theory. We show that a Coulomb or charge-frustrated Ising model, which accounts for both long-range Coulomb and short-range molecular interactions, simply describes some of these ionic correlations. In particular, we obtain, at a mean field level and in simulations, a non-monotonic dependence of the screening length on the temperature. Using a combination of simulations and mean field theories, we study how the correlations in the various regimes are affected by the strength of the short ranged interactions.
Real-time visualization of GaN/AlGaN high electron mobility transistor failure at off-state
Authors: Islam Zahabul , Haque Aman , Glavin Nicholas
Published: October 2018

Degradation and failure phenomena in high electron mobility transistors (HEMTs) are complex functions of electrical, thermal, and mechanical stresses as well as the quality of the device materials and their interfaces. Thus, it is difficult to predict or identify the dominant mechanism under various test protocols adopted in the literature. We propose that real-time visualization of the device microstructure can shift this paradigm. This is demonstrated by operating electron transparent AlGaN/GaN HEMTs inside a transmission electron microscope (TEM). Through the bright-field, diffraction, and energy dispersive spectroscopy techniques, we show that it is possible to characterize the lattice defects and diffusion of the various elements and thus monitor the microstructural quality during the transistor failure. Off-state failure studies in the TEM clearly show the critical role of defects and interfaces that lead to punch-through mechanisms at the drain and even source sides. The “seeing while measuring” approach presented in this study can be useful in pinpointing the dominant failure mechanisms and their fundamental origin.
Inertial migration of a rigid sphere in plane Poiseuille flow as a test of dissipative particle dynamics simulations
Authors: Huang Yuanding , Marson Ryan L. , Larson Ronald G.
Published: October 2018

After reviewing and organizing the literature on the problem of inertial cross-stream migration of rigid spheres in various geometries including tubes and channels, we use Dissipative Particle Dynamics (DPD) simulations to study the simplest case of migration of a single neutrally or non-neutrally buoyant sphere with diameter 20% of the gap in plane Poiseuille flow and assess the potential and limitations of DPD simulations for this and similar problems. We find that the neutrally buoyant sphere lags by up to 6% behind the surrounding fluid and is focused at a position around 50% of the distance between the channel center and the wall. With Re increasing from around 100 to 500, the sphere migrates closer to the channel center. With flow driven by gravity, a much denser non-neutrally buoyant sphere leads the surrounding fluid and is focused at a position closer to the wall, around 60% the distance from the channel center to the wall, in qualitative agreement with previous work. The lower values of the Schmidt number Sc in DPD simulations relative to real fluids, due to the relatively large diffusivity of DPD beads, are shown to not significantly affect the consistency of our DPD results with literature results although they make results noisy at low Re (i.e., ≲50). However, the increase in Ma and Wi with increasing Re leads to compressible flow effects and in some cases viscoelastic effects at high Re depending on the DPD parameters chosen. Even for optimally chosen parameters, we require Re≲500 to avoid strong compressibility effects. Thus, the relative simplicity of the DPD method for complex fluid flows is offset by the need to control the effects of unphysically high values of other parameters, such as Ma and Wi, which seriously limits the range of conditions under which DPD simulations give valid results in fluid transport problems.
One-step synthesis of highly-branched gold nanostructures and its application in fabrication of SERS-active substrates
Authors: Cao Xiaowei , Chen Shuai , Li Wei , Li Jianfeng , Bi Liyan , Shi Hongcan
Published: October 2018

In this paper, we reported a simple one-step synthesis of highly-branched gold nanostructures (HGNs) in high yields. The reduction of HAuCl4 was accomplished by dopamine hydrochloride in the reaction system. By varying the amount of dopamine hydrochloride, HAuCl4 and the reaction temperature, we managed to tune the size of the HGNs from 200 to 600 nm. Systematic analysis revealed that the optical properties and surface-enhanced Raman scattering (SERS) activities of the HGNs were highly dependent on their morphology and size. In terms of their SERS activities, it was found that the HGNs synthesized at 60 °C with 2.0 mL dopamine hydrochloride (53 mM), 0.4 mL HAuCl4 (50 mM) exhibited the largest SERS enhancement. When the HGNs were assembled onto the silicon wafers, outstanding SERS efficiency was obtained with a detection limit of 5×10-10 M of 4-mercaptobenzoic acid (4-MBA) and the analytical enhancement factor (AEF) was calculated to be 7×107. Besides, the 3-aminopropyltriethoxysilane (APTES)-functionalized substrates with the HGNs displayed remarkable signal reproducibility with relative standard deviation (RSD) of 3.57%. All these results demonstrated that the SERS-active substrates held great promise to be applied in trace-level molecule detection in the future.