bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of the Z-form of equations of steady-state modes of energy systems’ complex electric networks
Authors: Akhmetbayev Dauren , Akhmetbayev Arman , Zhantlessova Assemgul
Published: October 2018

This paper describes the state of the methodological problem of calculating steady-state modes of energy systems’ complex electric networks. It also describes the topological method of forming the Z-form of equations of steady-state modes of complex electric networks. The analytical dependence of the node impedance matrix with the matrix of the nodal currents distribution coefficients is established. The matrix of infeed coefficients is determined during the initial data preparation. An analytical approach for determining infeed coefficients topological essence is considered. A simplified method for calculating the driving current distribution coefficients is proposed based on all possible graph trees of a complex electric network. An algorithm for forming infeed coefficients matrix in the environment is developed. A technique for obtaining real solutions of the steady-state mode equations is developed. Steady-state modes direct formation significantly reduces the amount of work performed, increases the visibility of the calculation algorithms performance, and ensures fast and reliable iteration convergence. Increases the level of automation and efficiency of the calculations performed.
Electromagnetic safety enhancing in railway electric supply systems
Authors: Buyakova Natal’ya , Zakaryukin Vasiliy , Kryukov Andrey , Nguyen Tu
Published: October 2018

The methods of simulation modeling of traction power supply systems is developed, allowing analyzing the electromagnetic safety conditions in complex traction power networks equipped with sucking transformers. The effectiveness of the application of the sucking transformers (ST) connected in the rail cut with a distance of 3 km between transformers is small due to rails’ currents. The sucking transformers with return wires do not have this drawback. The use of ST with a return wire allows significantly improving the electromagnetic safety conditions: the level of magnetic field strength is reduced by tens of percent.
Analysis and modeling of harmonic distortions in consumer’s distribution networks, containing a powerful non-linear load
Authors: Rakhmanov N.R. , Kurbatsky V.G. , Guliyev H.B. , Tomin N.V. , Rakhmanov R.N.
Published: October 2018

The paper proposes to simulate a random variability of the nonlinear load in the form of probabilistic characteristics of the amplitudes of harmonic components of powers. The influence of the variability of distribution of amplitude values of the power harmonics on the load flow in the network, power losses and maximum power transmission in lines is studied. The results of design experiments for one of distribution networks of Azerbaijan power system, feeding the non-linear load, are given.
A single slot micro-ring structure for simultaneous CO2 and CH4 gas sensing
Authors: Zhang Weijia , Zhang Xin , Zhang Xiaowei , Jin Han , Jin Qinghui , Jian Jiawen
Published: October 2018

In this paper, we proposed a single silicon-on-insulator micro-ring structure for detecting two different gas components in the same time from one output spectrum. By introducing slot structure, the sensitivity and selectivity of sensor are improved. Specifically, two different sensing mechanisms are synthesized in this structure, thus output spectrum is impacted by varying concentrations of CH4 and CO2 respectively. The resonant wavelength of micro-ring resonator is the absorption peak of CH4, the concentration of CH4 can be measured with the light intensity change. Simultaneously, the combined action of CH4 and CO2 can cause the shift of resonant wavelength, and the total concentration of CH4 and CO2 gas can be obtained through the shift amount. For enhancing the evanescent field fraction in slot area and tuning the resonant wavelength of micro-ring being located on the absorption peak of CH4 (around 3.31 µm), the parameters of slot micro-ring structure, including height of slot in silicon, slot width, radius of micro-ring, waveguide width and the gap distance in coupling section, are well tailored, meanwhile, the quality factor Q of micro-ring is considered for ensuring a satisfied accuracy of sensor. A simulation based on the finite difference time domain method is implemented and the analysis results show that the sensitivity of sensor reaches 2308 nm/refractive index unit.
Geometrically nonlinear free and forced vibrations analysis of clamped-clamped functionally graded beams with multicracks
Authors: Chajdi Mohcine , Adri Ahmed , El bikri Khalid , Benamar Rhali
Published: October 2018

Geometrically nonlinear free and forced vibrations of clampedclamped Functionally Graded beams with multi-cracks, located at different positions, based on the equivalent rotational spring model of crack and the transfer matrix method for beams is investigated. The FG beam properties are supposed to vary continuously through the thickness direction. The theoretical model is based on the Euler-Bernoulli beam theory and the Von Karman geometrical nonlinearity assumptions. A homogenization procedure, taking into account the presence of the crack, is developed to reduce the problem examined to that of an equivalent isotropic homogeneous multi-cracked beam. Upon assuming harmonic motion, the discretized expressions for the total strain and kinetic energies of the beam are derived, and through application of Hamilton’s principle and spectral analysis, the problem is reduced to a nonlinear algebraic system solved using an approximate explicit method developed previously (second formulation) to obtain numerically the FG multi-cracked beam nonlinear fundamental mode and the corresponding backbone curves for a wide range of vibration amplitudes. The numerical results presented show the effect of the number of cracks, the crack depths and locations, and the volume fraction on the beam nonlinear dynamic response.
Nonlinear free and forced vibration of Euler-Bernoulli beams resting on intermediate flexible supports
Authors: Fakhreddine Hatim , Adri Ahmed , Rifai Saïd , Benamar Rhali
Published: October 2018

This paper deals with the geometrically nonlinear free and forced vibration analysis of a multi-span Euler Bernoulli beam resting on arbitrary number N of flexible supports, denoted as BNIFS, with general end conditions. The generality of the approach is based on use of translational and rotational springs at both ends, allowing examination of all possible combinations of classical beam end conditions, as well as elastic restraints. First, the linear case is examined to obtain the mode shapes used as trial functions in the nonlinear analysis. The beam bending vibration equation is first written in each span. Then, the continuity requirements at each elastic support are stated, in addition to the beam end conditions. This leads to a homogeneous linear system whose determinant must vanish in order to allow nontrivial solutions to be obtained. Numerical results are given to illustrate the effects of the support stiffness and locations on the natural frequencies and mode shapes of the BNIFS. The nonlinear theory is then developed, based on the Hamilton’s principle and spectral analysis. The nonlinear beam transverse displacement function is defined as a linear combination of the linear modes calculated before. The problem is reduced to solution of a non-linear algebraic system using numerical or analytical methods. The nonlinear algebraic system is solved using an explicit method developed previously (second formulation) leading to the amplitude dependent nonlinear fundamental mode of the BNIFS.
Theoretical and experimental investigation of parametrically excited piezoelectric energy harvester
Authors: Garg Anshul , Dwivedy Santosha K.
Published: October 2018

In the present work, a cantilever beam based piezoelectric energy harvester is investigated both theoretically and experimentally. The harvester is consists of a harmonically base excited vertical cantilever beam with a piezoelectric patch at the fixed end and a mass attached at an arbitrary position. The Euler-Bernoulli beam theory is applied considering the cantilever beam to be slender. The temporal nonlinear electromechanical governing equation of motion is obtained by using generalized Galerkin’s method considering two-mode approximation. Here for principal parametric resonance condition the steady state response of the voltage is obtained by using the method of multiple scales. The results are validated by developing an experimental setup of the harvester. For the harvester having a dimension of 295 mm×24 mm×7.6 mm, a maximum voltage of 40 V is obtained for a base motion of 9 mm with a frequency of 10.07 Hz when 15 gm mass is attached at a distance of 140 mm from the fixed end.
Recurrence analysis of fractional-order Lorenz system
Authors: Rysak Andrzej , Gregorczyk Magdalena
Published: October 2018

The fractional derivative is increasingly used in modeling of nonlinear systems. Fractional-order systems often give better fit to the experimental results, especially for the systems in which memory effects or hysteresis play a significant role. The paper presents numerical results obtained for Lorenz dynamical system, described by equations with the fractional derivative components. The impact of the fractional derivative terms on the system dynamics and stability is analyzed by using phase diagrams and recurrence plot analysis.
Dynamic response of double-beam system with nonlinear viscoelastic layer to moving load
Authors: Koziol Piotr , Pilecki Rafał
Published: October 2018

In previous papers, the problem of double-beam system resting on viscoelastic foundation was solved with the assumption of nonlinear foundation stiffness. This multilayer model finds application in railway modelling, where rails are represented by the infinite Euler-Bernoulli beams and sleepers are modelled as a rigid body. In this paper, another assumption is made. The layer connecting two Euler-Bernoulli beams has nonlinear stiffness. This assumption is related to laboratory tests of fastening systems. These tests show that the stiffness of fasteners and rail pads is nonlinear and this factor should be taken into account in detailed analysis of dynamic features. Therefore inclusion of nonlinearity in double-beam system is justified. The physical model presented in this paper consists of two infinitely long beams connected by viscoelastic layer with nonlinear stiffness and resting on viscoelastic foundation. The mathematical model is described by two coupled fourth order partial differential equations of motion with homogeneous boundary conditions. The system is solved by using the Fourier transform and Adomian’s decomposition, combined with the wavelet based approximation of the response using Coiflet filters. The error index for Adomian series is proposed and the approximate solution for vertical vibrations is shown along with computational examples for some systems of parameters.
Vehicle response on kinematic excitation
Authors: Valašková Veronika , Melcer Jozef
Published: October 2018

The vehicle - roadway interaction is actual engineering problem solved on many workplaces in the world. At the present time preference is given to numerical and experimental approaches. Vehicle designers are interested in the vibration of the vehicle and the forces acting on the vehicle. Civil engineers are interested in the load acting on the road. Solution of the problem can be carried out in time or in frequency domain. Road unevenness is the main source of kinematic excitation of the vehicle and therefore the main source of dynamic forces acting both on the road and the vehicle. The offered article deals with one of the possibilities of numerical analysis of the vehicle response in frequency domain. It works with quarter model of the vehicle. For the selected computational model of the vehicle it quantifies the Frequency Response Functions (FRF) of both force and kinematic quantities. It considers the stochastic road profile. The Power Spectral Density (PSD) of the road profile is used as input value for the calculation of Power Spectral Density of the response. All calculations are carried out numerically in the environment of program system MATLAB. When we know the modules of FRF or the Power Response Factors (PRF) of vehicle model the calculation of vehicle response in frequency domain is fast and efficient.
Effect of adding mass to rotor on in-plane squeal in automotive disc brake
Authors: Nakae Takashi , Ryu Takahiro , Goto Hiroki , Sato Daisuke
Published: October 2018

This study experimentally examined disc brake-generated inplane squeal by looking at vibration modes. The in-plane squeal was determined to be closely related to both the out-of-plane squeal that has directionality caused by Coulomb friction and the in-plane squeal caused by dry friction. The characteristics of in-plane squeal were also analytically investigated using a concentrated mass model formed by connected massless beams, and the relationship between mass added to the rotor and squeal suppression was clarified.
Limitations of a dynamic shear-frame model based in a small-scale experimental steel structure
Authors: de S. Pippi Augusto , Bernardes Júnior Pedro L. , Avila Suzana M. , de Morais Marcus V. G. , Doz Graciela
Published: October 2018

Many engineering problems require geometric modeling and mechanical simulation of structures. Through the structural models, engineers try to simulate the real behavior of these structures. It is important that a model contain all the necessary parameters that describe the structure and its behavior during its useful life. In the field of dynamics, one of the most used models is the shear-frame, in which the stiffness of the structure is given by the stiffness of the columns and the whole mass is concentrated in the floor levels, which are considered with infinite stiffness. In some cases, this simplification offers more conservative results, which can lead to considerable errors, especially in the case of natural frequencies. Knowing that the quality of a structural model depends on the simplifications considered, an experimental 3D steel frame, constructed to typify the dynamic behavior of a tall building, was tested with a data acquisition system and accelerometers, in order to obtain its natural frequencies. In addition, a numerical model was developed in order to ascertain the results. These values of natural frequencies are compared with an idealized shear-frame model obtained from the experimental model. This comparison allows a critical analysis of the numerical models that can be employed to represent the real dynamic behavior of structures. The aim of the investigation is to show the results of the modal analysis for each model, comparing them with the experimental results and commenting their advantages and the limitations.
Identification of vibration properties of a midrise wooden building using subspace identification method
Authors: Miyazu Yuji , Mori Takuro
Published: October 2018

Recent years, the mid- and high-rise wooden building using cross-laminated timber (CLT) is on the increase in the world. In the regions highly subjected to seismic events, it is important to know the basic property of the vibration of the building to design the building to be safety enough against the seismic load; however, there is enough such data of full scale wooden buildings. In this paper, the natural period, the damping ratio, and the mode shape of a full-scale five-story wooden building are evaluated using subspace identification method. The results show that the damping ratios of higher modes tend to be lower than that of the first mode, and the natural period and the damping ratio show amplitude dependency even in the range of low amplitude.
Hydrodynamic aspects of moving vehicle with sloshing tanks
Authors: Han Mengmeng , Dai Jian , Ang Kok Keng
Published: October 2018

Freight vehicles with partially filled liquid tanks will be affected by liquid sloshing during transient motion. The sloshing induced by vehicle motion will lead to extra force on the vehicle and sometimes is a potential threat to safety. Previous studies on this problem usually use a mass-spring analogy to represent the sloshing effect of the liquid tank. Its main disadvantage is that CFD analysis or experimental study has to be performed beforehand, so that an equivalent mass-spring model can be constructed by curve fitting. In this paper, frequency domain boundary element method (BEM) and analytical solution to the sloshing problems are used to derive the modal equation and hydrodynamic parameters of the sloshing fluid. The accuracy of the results will be examined by comparison with available CFD results in the literature. The paper then evaluates the accuracy of equivalent mass-spring model and explores the possibility to approximate the sloshing effects inside cylindrical tanks by using analytical solution to the sloshing inside equivalent rectangular tanks.
Frequency response of a liquid sloshing in a rotating, laterally oscillating, cylindrical vessel
Authors: Yokose Eisaku , Saito Yusuke , Sawada Tatsuo
Published: October 2018

We have investigated the free-surface fluctuations of liquid in a rotating, laterally oscillating, cylindrical vessel. In the experiments, we changed independently both the lateral forcing frequency f and the rotation frequency Ω of the cylinder. We measured the time-dependent fluid-dynamic pressure instead of the free surface fluctuations. From an FFT analysis of the dynamic pressure, we obtained two significant frequencies: f - Ω and f + Ω. They are associated, respectively, with waves that rotate in the same direction, and in the opposite direction, relative to the rotation of the vessel. We also examined these results using linearized wave theory.
Prediction of flow induced vibrations in vertical turbine pumps using one-way fluid-structure interaction
Authors: Birajdar Ravindra , Keste Appasaheb
Published: October 2018

Centrifugal pumps/vertical turbine pumps are important and critical equipment for operation in the power generation, water supply, process industries and petrochemical industries. All centrifugal and vertical turbine pumps have rotors and structures that can vibrate in response to excitation forces. Mechanical and hydraulic unbalance are the two major factors which can create dynamic effects in terms of pump vibrations. In many cases the resulting hydraulic forces due to hydraulic unbalance has much the same effect as the mechanical unbalance. The vibrations in the pumps must be within acceptable limits of applicable standards. If there is higher level of vibrations, it not only leads to operational inefficiencies but also causes pump failures. Hence, it is very important for designers to understand the dominating fact of unbalance force and its origin. The prediction of vibrations in a vertical turbine pump due to the hydro dynamic forces, using numerical methods can help a designer to accomplish a successful design. The interaction between solid and fluid in present case can be completed by one-way coupling method. The one-way fluid-structure interaction approach is presented in present paper to predict the vibrations at specific operating condition which has good correlation with the test data. The advantage of reduced computational effort in this approach can be utilized during initial design stage. In this paper, a case study of one-way FSI approach of a vertical turbine pump is discussed. After detailed explanation about the CFD results, one-way coupling approach is explained with comparison of vibration displacements in both numerical and test data.
Simulation of plastic deformation and destruction in the process of chip formation
Authors: Tärgla Tanel , Olt Jüri , Liivapuu Olga
Published: October 2018

Metal cutting is a complex process in which several mechanisms are at work simultaneously. The mathematical modelling allows carrying out research into the optimization of machining conditions. This work examines the simulation of chip formation during the process of cutting. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elasticductile- plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for the chip formation process. The key factors that govern the chip formation have been taken into account, such as tool vibration frequency and amplitude, depth of cut, feed rate.
Data fusion of acceleration and velocity features (dFAVF) approach for fault diagnosis in rotating machines
Authors: Luwei Kenisuomo C. , Sinha Jyoti K. , Yunusa-Kaltungo Akilu , Elbhbah Keri
Published: October 2018

Earlier research studies have suggested the unified vibration-based approach for fault diagnosis (FD) in identical machines with different foundation flexibilities and multi-rotating speeds. Intially the acceleration-based features were used for this approach then further work optimised the approach by combining acceleration and velocity features from vibration data for analysis. However the optimised approach was only tested on the identical machines rotating at different speeds below the machine’s first critical speed. The current paper tends to observe the optimised approach when applied to a test rig operating below and above the machine’s first critical speed.
Assessing the effectiveness of botulinum toxin injections into masticatory muscles in the treatment of temporomandibular disorders
Authors: Kahn Alexis , Bertin Helios , Corre Pierre , Praud Morgan , Paré Arnaud , Kün-Darbois Jean-Daniel
Published: October 2018

Introduction: Temporomandibular disorders (TMD) are a common and invalidating disease sometimes difficult to treat. Current international recommendations favour reversible and non-invasive treatments, including the injection of botulinum toxin (BTX) into masticatory muscles. There is no strong evidence of its effectiveness. Objective: The main goal of this study was to assess the effectiveness of BTX six months following injection, in terms of pain, mouth opening, improvement of symptoms and duration of effect. Materials and methods: A retrospective study carried out at Nantes University Hospital between 2014 and 2016. Results: Thirty-four patients were included. The mean age was 37 years (17–76) and seventy six percents were female. Eighty percent of patients reported a significant improvement, notably in cases of arthralgia, which decreased in 8/18 (44%) patients (p < 0.05). The mean duration of measured efficacy was 4.2 months. Discussion: Significant improvement in cases of arthralgia and a tendency for improvement in cases of myalgia, with a mean duration of action of 4.2 months. Although BTX injection do not guarantee complete resolution of myofascial pain, it have been shown to have beneficial effects on some symptoms have been shown. Conclusion: Botulinum toxin should be considered as an alternative treatment when other conservative methods fail to yield satisfactory results. A thorough multicentre assessment is necessary in the future to scientifically validate its use.
Pattern of maxillofacial injuries in patients with craniocerebral injuries: a prospective study
Authors: Agbara Rowland , Obiechina Ambrose Emeka , Ajike Sunday Olusegun , Adeola Davis Sunday
Published: October 2018

Introduction:This prospective study highlights the pattern of oral and maxillofacial injuries in patients with associated craniocerebral injuries.Material and Methods:This was a prospective descriptive study conducted over a 22-month period. Information was collected using a structured questionnaire and analyzed using Statistical Package for Social Sciences (SPSS) Version 13 (SPSS Inc., Chicago, IL, USA) and Microsoft Office Excel 2007 (Microsoft, Redmond, WA, USA). Test of statistical significance was set at 0.05.Results:Three hundred and three consecutive patients were studied and this consisted of 254 males and 49 females. The difference in the gender distribution was statistically significant (p = 0.008). Road traffic crashes (n = 262; 86.5%) was the most common cause of injury and soft tissues orofacial injuries accounted for 61.7% of injuries. Le Fort II fractures were the major skeletal injuries. Glasgow Coma Score (GCS) of 13–15 had the highest frequency (n = 157; 53.4%). Intracerebral haemorrhage was the most common cerebral injury recorded and the commonest complication noted was dysocclusion.Discussion:Although middle third facial fractures were the most common skeletal injury, fractures of the upper third facial skeleton appear to be associated with lower GCS.Conclusion:Fractures of the facial skeleton are fairly common in craniocerebral injuries.
An unusual case of microcystic lymphatic malformation discovered after wisdom teeth extraction
Authors: Thévenon Joannice , Barthelemy Isabelle , Pham-Dang Nathalie , Devoize Laurent
Published: October 2018

Lymphangioma is a benign vascular malformation of the lymphatic vessels. In 90% of cases it is diagnosed during the first 2 years of life. As seen in 75% of cases, the head and neck region are the preferred location. This report represents an original case of lymphatic malformation (LM) in a 15-year-old patient discovered during an unscheduled postoperative symptomatology of third molar germectomies. Two biopsies, one non-contributory, were required to make the diagnosis. Lymphangiomas are classified as LM. They are usually non-regressive. Their etiology remains controversial.
Empirisme intelligent, petites séries de cas et recherche frugale
Authors: Odier Bernard
Published: October 2018

Un clinicien qui rencontre dans son activité quotidienne sur d’assez longues périodes des malades gagne leur confiance et peut accéder à des connaissances cliniques dont certaines reposent sur des confidences. Cette cueillette clinique est hors de portée des questionnaires construits pour être applicables en quelques instants quelles que soient la culture et la langue. Le thérapeute est à la fois l’acteur et le témoin de séquences évolutives, parfois liées à ses interventions thérapeutiques. Son travail clinique une fois formalisé peut s’inscrire dans des études prometteuses en termes de connaissances des liens entre les interventions des thérapeutes et les changements chez les patients grâce à une connaissance fine de leurs troubles et de leurs évolutions. Celles-ci méritent d’être formalisées afin d’être reconnues et que leur éventuelle portée générale soit établie.

L’article détaille aussi comment un clinicien attentif peut, en s’appuyant sur des petites séries de cas, détecter des régularités à même de constituer des hypothèses pour d’autres cliniciens. La sagacité d’un observateur permet des découvertes qui ne sont qu’apparemment dues au hasard. L’auteur souligne l’importance de l’empirisme et de la sérendipité dans les progrès de la thérapeutique psychiatrique. Des tâches importantes d’investigation clinique appartiennent aujourd’hui encore au clinicien. Les transitions entre la remarque clinique, la petite série de cas, la recherche-action, l’étude-pilote et la recherche clinique doivent être encouragées. Les étapes à franchir pour contribuer à la marche en avant des connaissances cliniques et thérapeutiques sont illustrées. Elles peuvent être facilitées par des dispositifs de type « Fablab ». Elles s’accommodent du cadre souple et de la réactivité de la recherche frugale.
Vergleich einer kommerziell erhältlichen, Formula-basierten, mit Haferballaststoffen angereicherten Ernährungstherapie mit einer isokalorischen diätetischen Therapie ohne Formula zur Therapie der nicht-alkoholischen Fettlebererkrankung (NAFLD) – eine randomisierte, kontrollierte Interventionsstudie
Authors: Schweinlin Anna , Ulbrich Sina , Stauß Sina , Teutsch Melanie , Walle Hardy , Basrai Maryam , Bischoff Stephan
Published: October 2018

Die nicht-alkoholische Fettlebererkrankung (NAFLD) wird primär mittels Kalorienrestriktion mit konsekutiver Reduktion des Körpergewichts behandelt. Ein Austausch von Stärke und Zucker gegen Protein, einfach ungesättigte und langkettige Omega-3-Fettsäuren wie auch präbiotisches β-Glucan sollen dabei unterstützend wirken.

In einer randomisierten, kontrollierten Interventionsstudie wurde der Effekt zweier Diätkonzepte auf den hepatischen Lipidgehalt und biochemische Parameter an Patienten mit Body-Mass-Index (BMI) > 30 kg/m2 und Zeichen einer Fettlebererkrankung untersucht. Die Interventionsgruppe (IG, n = 17) erhielt eine kommerziell erhältliche Formula-Diät mit Haferballaststoffen, die Kontrollgruppe (KG, n = 19) wurde auf eine kalorisch vergleichbar beschränkte Kost (ca. 1000 kcal/Tag) nach der Methodik der „low glycemic and insulinemic diet“ eingestellt.

Beide Diätkonzepte führten nach 12 Wochen zu einer Reduktion des BMI (IG: von 33,8 ± 2,9 nach 29,3 ± 2,5 kg/m2, KG: von 33,7 ± 2,8 nach 30,1 ± 3,2 kg/m2, beide p < 0,001) sowie zu einer Verbesserung der Leberfunktion und der metabolischen Situation. Der hepatorenale Index verringerte sich in beiden Gruppen, allerdings in der IG deutlicher als in der KG (Studienende: 1,1 ± 0,2 vs. 1,9 ± 0,3, p < 0,05). Eine Blutdruckreduktion trat nur in der IG auf (systolisch von 136 ± 15 auf 122 ± 11 mmHg, diastolisch von 89 ± 9 auf 79 ± 11 mmHg, beide p < 0,01).

Zusammenfassend sind beide diätetischen Interventionen ähnlich effektiv hinsichtlich Gewichtsreduktion, aber die Intervention mit der Formula-Diät mit Haferballaststoffen war hinsichtlich der Reduktion des Leberfettgehalts und der Blutdrucksenkung effektiver als die Kontroll-Diät.
Concise Synthesis of Tryptanthrin Spiro Analogues with In Vitro Antitumor Activity Based on One-Pot, Three-Component 1,3-Dipolar Cycloaddition of Azomethine Ylides to Сyclopropenes
Authors: Boitsov Vitali , Stepakov Alexander , Filatov Alexander , Knyazev Nickolay , Shmakov Stanislav , Bogdanov Alexey , Ryazantsev Mikhail , Shtyrov Andrey , Starova Galina , Molchanov Alexander , Larina Anna
Published: October 2018

A simple, efficient and atom-economic method has been developed for the synthesis of complex alkaloid-like compounds with spiro-fused indolo[2,1-b]quinazoline and cyclopropa[a]pyrrolizine or 3-azabicyclo[3.1.0]hexane moieties. We have found that one-pot, three-component 1,3-dipolar cycloaddition reactions allow the desired products to be obtained from various cyclopropene derivatives with tryptanthrin-derived azomethine ylides generated in situ, in good to high yields and excellent diastereoselectivity. The possibility of ylide generation was exemplified by using α-amino acids (l-proline, l-4-thiazolidincarboxylic acid) and simplest peptides (dipeptide Gly-Gly, tripeptide Gly-Gly-Gly). Quantum chemical investigations indicate that the reaction proceeds through the S-shaped azomethine ylide, the interaction of which with cyclopropenes proceeds via a less sterically hindered endo-transition state. The antitumor activity of some of spiro-tryptanthrin derivatives against erythroleukemia (K562), cervical carcinoma (HeLa) and colon carcinoma (CT26) cell lines was evaluated in vitro by MTS-assay.
Growth of Pituitary Macroadenomas Postpartial Resection: Implications for Adjuvant Radiotherapy
Authors: Panet-Raymond Valerie , Sabit Kushraw , Shenouda George , Sirhan Denis , Zeitouni Anthony , Souhami Luis
Published: October 2018

Objective To determine the volumetric growth in macroadenomas (MAs) patients with residual postoperative disease and to identify subpopulations with rapid postoperative growth rate that may benefit from early salvage radiotherapy (RT).

Methods Patients who had undergone a partial resection for MAs and did not receive immediate postoperative RT were eligible. Residual tissue was contoured on serial magnetic resonance imaging and planimetric and volumetric changes in size were measured. Growth rates were established by a single observer using serial volumetric measurements. Data were analyzed to find a relationship among growth rate, adjuvant treatment, and patient and tumor characteristics.

Results Thirty-one patients met the eligibility criteria. Nine patients (29%) required adjuvant treatment because of tumor growth. Volumetric growth was identified 95% of the time compared with 64% planimetrically. Planimetric growth could not be established in 10% of patients showing volumetric changes. Median growth rate was 0.4464 mL/y. Growth rate positively correlated with size of residual postoperative volume (p < 0.001). Receiving salvage treatment positively correlated with growth rate (p = 0.001), particularly at a rate above 2.19 mL/y (p = 0.0064). Five patients (16%) had a growth rate above this level, all of which required salvage treatment. Patients with postoperative residual volume > 3.95 mL were most likely to experience rapid growth rate and require salvage treatment (p = 0.007).

Conclusion Volumetric measurement was found to be superior to planimetric measurement in detecting changes in patients with residual tumors. Patients with postoperative residual volume > 3.95 mL should be considered for early treatment with RT.
A dot-line square super-lattice pattern with surface discharge in dielectric barrier discharge
Authors: Huang Jiayu , Pan Yuyang , Liu Fucheng , Han Rong , Sun Haoyang , Mi Yanlin , Liu Binbin , Cui Yiqian , Dong Lifang
Published: October 2018

We report a dot-line square super-lattice pattern with surface discharge (DLSSPSD) in a dielectric barrier discharge system and show for the first time that the surface discharge can promote the formation of volume discharge (VD). The pattern consists of three different discharge morphologies, namely, bright spots, dim spots, and bright lines. The spatiotemporal dynamics of the DLSSPSD are studied using an intensified charge-coupled device camera, a photomultiplier, and a high-speed video camera. The results show that the VD located at the dim spots and bright lines is generated on both the rising and falling edges of the voltage. It is found that the high surface charge density transferred by the surface discharge of the bright spots promotes the formation of VD at the dim spots and bright lines.
Real-time distributed monitoring of pressure and shock velocity by ultrafast spectrometry with Chirped Fiber Bragg Gratings: Experimental vs calculated wavelength-to-pressure sensitivities in the range [0–4 GPa]
Authors: Magne S. , Barbarin Y. , Lefrançois A. , Balbarie M. , Sinatti F. , Osmont A. , Luc J. , Woirin K.
Published: October 2018

Fiber Bragg Gratings (FBGs) are gaining acceptance as velocity/pressure gauges in the fields of detonation and shock physics on account of their sensitivity, small size, flexibility, electromagnetic immunity, and wavelength-encoded feature. Chirped FBGs (CFBGs) are investigated as wavelength-to-position discriminators with the purpose of monitoring pressure/velocity profiles over a distance range of typically 100 mm. The use of CFBGs simplifies both sensor deployment and data retrieval and finally improves the accuracy due to the increased number of measurement data. In this paper, the metrological performance of CFBGs used as in situ distributed shock pressure/velocity gauges is investigated both theoretically and experimentally in a planar shock loading configuration with an aluminum-based flyer and target. In the intermediate range for shock stress, i.e., less than the Hugoniot Elastic Limit (HEL) of silica, CFBGs provide simultaneous measurements of both shockwave velocity and stress within the target material. A Bragg wavelength-to-stress model is proposed that takes into account (i) the state-of-stress within the target material, (ii) the stress coupling coefficient due to imperfect impedance matching between the target material and the silica fiber, (iii) the conversion of the state-of-stress into a state-of-strain within the silica fiber, and (iv) the conversion of strain data into observable Bragg wavelength shifts. Finally, the model also takes into account the pressure dependence of constitutive parameters for silica and aluminum. Experiments were performed in planar shock loading using CFBGs as stress gauges, bonded along the target axis with Araldite glue. 6061-T6 aluminum flyers were launched at several velocities by a gas gun onto targets of the same material. A free-space Czerny-Turner (CT) spectrometer and an integrated-optics Arrayed-Waveguide Grating (AWG) were both used as dynamic spectrum analyzers. Experimental Bragg wavelength shifts agree well with theoretical predictions for both elastic and hydrodynamic planar shock loading of 6061-T6 aluminum, opening up large perspectives for shock physics experiments.
Optimizing the design of composite phase change materials for high thermal power density
Authors: Barako Michael T. , Lingamneni Srilakshmi , Katz Joseph S. , Liu Tanya , Goodson Kenneth E. , Tice Jesse
Published: October 2018

Phase change materials (PCMs) provide a high energy density for thermal storage systems but often suffer from limited power densities due to the low PCM thermal conductivity. Much like their electrochemical analogs, an ideal thermal energy storage medium combines the energy density of a thermal battery with the power density of a thermal capacitor. Here, we define the design rules and identify the performance limits for rationally-designed composites that combine an energy dense PCM with a thermally conductive material. Beginning with the Stefan-Neumann model, we establish the material design space using a Ragone framework and identify regimes where hybrid conductive-capacitive composites have thermal power densities exceeding that of copper and other high conductivity materials. We invoke the mathematical bounds on isotropic conductivity to optimize and define the theoretical limits for transient cooling using PCM composites. We then demonstrate the impact of power density on thermal transients using copper inverse opals infiltrated with paraffin wax to suppress the temperature rise in kW cm−2 hotspots by ∼10% compared to equivalent copper thin film heat spreaders. These design rules and performance limits illuminate a path toward the rational design of composite phase change materials capable of buffering extreme transient thermal loads.
High resolution gamma-ray spectrometer with MHz capabilities for runaway electron studies at ASDEX Upgrade
Authors: Nocente M. , Shevelev A. , Giacomelli L. , Pautasso G. , Tardocchi M. , Gin D. , Gobbin M. , Gorini G. , Fernandes A. , Herrmann A. , Khilkevitch E. , Panontin E. , Papp G. , Pereira R. C. , Salewski M. , Tardini G. , Valisa M. ,   ASDEX Upgrade Team,   EUROfusion MST1 Team
Published: October 2018

A new gamma-ray spectrometer with MHz capabilities has been developed to measure the bremsstrahlung emission spectrum in the gamma-ray energy band generated by MeV range runaway electrons in disruption experiments at ASDEX Upgrade. Properties of the runaway electrons are inferred from the measured bremsstrahlung spectrum by a deconvolution technique, particularly with regard to their maximum energy. Changes induced to the runaway electron velocity space are unambiguously observed both in massive gas injection and resonant magnetic perturbation experiments with the detector.
Velocity correction for neutron activation diagnostics at the NIF
Authors: Rinderknecht Hans G. , Bionta R. , Grim G. , Hatarik R. , Khater H. , Schlossberg D. , Yeamans C.
Published: October 2018

The velocity distribution of the hotspot in an inertial confinement fusion implosion changes the energy spectra of fusion neutrons emitted from the experiment as a function of viewing angle. These velocity-induced spectral changes affect the response of neutron activation diagnostics (NADs) positioned around the experiment and must be accounted for to correctly extract information about areal density (ρR) asymmetry from the data. Three mechanisms through which average hotspot velocity affects NAD activation are addressed: change in activation cross section due to the Doppler shift of the mean neutron energy, kinematic focusing of neutron fluence, and change in the scattering cross section due to the Doppler shift. Using the hotspot velocity inferred from neutron time-of-flight measurements of D-T and D-D fusion neutrons, the hotspot velocity is shown to account for the observed NAD activation asymmetry in a calibration shot with negligible fuel ρR. A robust method to evaluate uncertainties in spherical-harmonic fits to the NAD data due to the velocity correction and detector uncertainty is discussed.
Signal to noise ratio of upgraded imaging bolometer for KSTAR
Authors: Peterson Byron J. , Oh Seungtae , Seo Dongcheol , Jang Juhyeok , Park Jae Sun , Mukai Kiyofumi , Choe Wonho
Published: October 2018

An InfraRed imaging Video Bolometer (IRVB) was installed on KSTAR in 2012 having a ∼2 μm × 7 cm × 9 cm Pt foil blackened with graphite and a 5 mm × 5 mm aperture located 7.65 cm from the foil with 16 × 12 channels and a time resolution of 10 ms. The IR camera was an Indigo Phoenix (InSb, 320 × 256 pixels, 435 fps, <25 mK). In 2017, the IRVB was upgraded by replacing the IR camera with a FLIR SC7600 (InSb, 640 × 512 pixels, 105 fps, <25 mK). The aperture area was reduced by approximately half to 3.5 mm × 3.5 mm, and the number of channels was quadrupled to 32 × 24. A synthetic image derived using the projection matrix for the upgraded IRVB from a Scrape Off Layer Plasma Simulator (SOLPS) model with 146 kW of total radiated power had a maximum signal of 7.6 W/m2 and a signal to noise ratio (SNR) of 11. Experimental data for a plasma with parameters similar to the SOLPS model (total radiated power of 158 kW) had a maximum signal of 12.6 W/m2 and noise equivalent power density (SNR) of 0.9 W/m2 (14).
Design of gamma-ray spectrometers optimized for fast particle studies at ITER
Authors: Rebai M. , Bertalot L. , Brichard B. , Brolatti G. , Croci G. , Esposito B. , Fernandes A. , Giacomelli L. , Gorini G. , Krasilnikov V. , Lengar I. , Marocco D. , Muraro A. , Nocente M. , Pereira R. C. , Perelli Cippo E. , Rigamonti D. , Rzadkiewicz J. , Sousa J. , Tardocchi M.
Published: October 2018

A set of gamma ray spectrometers has been designed for ITER within the Radial Gamma Ray Spectrometer (RGRS) project. The aim of this project is designing a system, integrated with the ITER radial neutron camera, which is able to measure the gamma-rays emitted from the plasma with a good energy resolution (about 1.5% at 4.44 MeV) and at high counting rates (in excess of 1 MHz). The RGRS will be able to operate both in the D phase and in the full-power DT phase and will measure gamma rays from (i) reactions between fast ions, such as α particles, and light impurities and (ii) bremsstrahlung emission generated by runaway electron interactions with both plasma bulk and tokamak walls. The RGRS detectors are arranged in nine lines of sights (able to cover a radial region with r < a/3), each featuring a large LaBr3 scintillator crystal. Due to the high neutron flux and magnetic field, several solutions have been adopted to guarantee a good signal to background ratio and MHz counting rate capabilities. The RGRS is capable to combine space and energy distribution measurements of α particles and runaway electrons, which will help the study of the fast particle physics in a burning plasma.
Aperture design for the third neutron and first gamma-ray imaging systems for the National Ignition Facility
Authors: Fatherley V. E. , Fittinghoff D. N. , Hibbard R. L. , Jorgenson H. J. , Martinez J. I. , Oertel J. A. , Schmidt D. W. , Waltz C. S. , Wilde C. H. , Volegov P. L.
Published: October 2018

The current construction of a new nuclear-imaging view at the National Ignition Facility will provide a third line of sight for hotspot and cold fuel imaging and the first dedicated line of sight for 4.4-MeV γ-ray imaging of the remaining carbon ablator. To minimize the effort required to hold and align apertures inside the vacuum chamber, the apertures for the two lines of sight will be contained in the same array. In this work, we discuss the system requirements for neutron and γ-ray imaging and the resulting aperture array design.
Lower-hybrid drift instability and macroscopic flow of colliding magnetized plasmas
Authors: Malkov M. A. , Sotnikov V. I.
Published: October 2018

Microscopic instability and the macroscopic flow pattern resulting from colliding plasmas are studied analytically in support of laboratory experiments. The plasma flows are assumed to stream radially from two separate centers. In a quasi-planar (2D) geometry, they may arise from an Ohmic explosion of two parallel wires, but similar configurations emerge from other outflows, e.g., colliding winds in binary star systems. One objective of this paper is to characterize the flow instabilities developing near the flow stagnation line. An exact solution for the Buneman-type dispersion equation is obtained without conventional simplifications. The unstable wave characteristics are key to anomalous resistivity that determines the reconnection rate of opposite magnetic fields transported with each flow toward the stagnation zone. The second objective of this paper is to calculate the stream function of the plasma shocked upon collision. We addressed this task by mapping the flow region to a hodograph plane and solving a Dirichlet problem for the stream function. By providing the instability growth rate, responsible for anomalous transport coefficients, and the overall flow configuration, these studies lay the ground for the next step. From there, we will examine the field reconnection scenarios and emerging mesoscopic structures, such as radial striata observed in the experiments.
Measurement of water vapor diffusion in nanoscale polymer films by frequency-domain probe beam deflection
Authors: Xie Xu , Dennison Jordan M. , Shin Jungwoo , Diao Zhu , Cahill David G.
Published: October 2018

We developed an optical pump-probe technique, frequency-domain probe beam deflection (FD-PBD) to measure the diffusion of water vapor in nanoscale polymer films with microsecond temporal resolution and micrometer spatial resolution. We describe the quantitative model of beam deflection for multilayer structures, the experimental approach, and the application of FD-PBD to measure the diffusivity (Dm) of saturated water vapor in various glassy polymer films including polyimide (PI, Dm = 7.0 × 10−13 m2 s−1), poly(methyl methacrylate) (PMMA, Dm = 1.2 × 10−12 m2 s−1), poly-(vinylpyrrolidone) (PVP, Dm = 1.7 × 10−12 m2 s−1), and cellulose acetate (CA, Dm = 2.6 × 10−11 m2 s−1), and the piperazine/trimesoyl chloride (PIP/TMC, Dm = 9 × 10−11 m2 s−1) nanofiltration membrane synthesized by interfacial polymerization. The uncertainty of the measurements is typically ≈8%.
Simulation of coupled spin torque oscillators for pattern recognition
Authors: Popescu Bogdan , Csaba Gyorgy , Popescu Dan , Fallahpour Amir Hossein , Lugli Paolo , Porod Wolfgang , Becherer Markus
Published: October 2018

In this paper, we use circuit-level simulations to investigate the synchronization dynamics of spin torque oscillators (STOs) and demonstrate a pattern recognition scheme based on STO dynamics. We perform a sensitivity analysis in order to determine the robustness of the different STO coupling methods, considering parameter variations, such as radius or thickness of STOs. After pointing out the advantages of the cross coupled architecture, we demonstrate a coupling scheme for pattern recognition. Several patterns are encoded in the resistive coupling network and are successfully identified, after the network has been initialized correspondingly. Finally, by extracting the corresponding impulse sensitivity function, we show how an existing analytical phase domain model can be adapted to the STO array. We compare the results of this analytical model with the numerical model of the STO and conclude that they agree well providing thus a fast method for design.