bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of hybrid model based on Lattice Boltzmann Method and Cellular Automata devoted for phase transformation – simulation of heat flow with consideration of enthalpy
Authors: Łach Łukasz , Straka Robert , Svyetlichnyy Dmytro
Published: November 2018

In heat treatment of materials, the phase transformation is an important phenomenon, which determines the final microstructure. The microstructure of different materials described by such parameters as morphology, grain size, phase fraction and their spatial distribution, largely effects on the mechanical and functional properties of final products. The subject of the work is a development of a hybrid model based on CA and Lattice Boltzmann method (LBM) for modeling of the diffusion phase transformation. The model has a modular structure and simulates three basic phenomena: diffusion, heat flow and phase transformation. The objective of the paper is a presentation of module of the hybrid model for simulation of heat flow with considering of enthalpy of transformation. This is one of the stages in the development of the model and obtained results will be used in a combined solution of heat transfer and diffusion during the modeling of diffusion phase transformations. Lately, the model will be extended to three dimensions and will use hybrid computational systems (CPU and GPU). CA and LBM are used in the model as follows. LBM is used for modeling of heat flow, while CA is used for modeling of microstructure evolution during the phase transformation. The main factors considered in the model are the enthalpy of transformation and heat transfer. The paper presents the results of the modeling of the new phase growth determined by different values of overcooling affecting on different values in the enthalpy of transformation. The heat flow is simulated and the results for some modeling variants are shown. Examples of simulation results obtained from the modeling are presented in the form of images, which present the growth of new phase and temperature distributions.
Effect of baffle shape in heat transfer for jet impingement on a solid block
Authors: Marimuthu Muthukannan , Uthayakumar  , Kanna P Rajesh , Ocłoń Paweł , Taler Jan , Taler Dawid
Published: November 2018

The numerical solution solution is obtained for fluid flow and heat transfer in a confined impinging slot on a solid block with the presence of baffles. In order to consider the effect of baffle shape the rectangular and semi circular baffles are considered and for the effect for Reynolds number the Reynolds number is varied from 100 to 300 with the step of 50. The present study reveals the vital impact of Baffle shape and Reynolds number (Re) on the fluid flow and heat transfer characteristics over a wide range. It is finally added that the presence of baffle improves the Nusselt number. The Nusselt number increases with the increase of Reynolds number. The present study proved that, the primary peak of Nusselt number occurs nearer to the reattachment length. The secondary peak of Nusselt number occurs nearer to the baffle. It is observed that for semi circle baffle the velocity attains maximum one compared to rectangular baffle.
Heat transfer study on a hybrid smooth and spirally corrugated tube
Authors: Yang Chen , Chen Min-rui , Qian Jin-yuan , Wu Zan , Jin Zhi-jiang , Sunden Bengt
Published: November 2018

Corrugated tubes are widely used in a range of applications for heat transfer enhancement. The spirally corrugated tube has a better heat transfer performance than the smooth tube. In this paper, the heat transfer performance of a hybrid smooth and six-start spirally corrugated tube is studied. With a validated numerical model, the effects of the corrugation part length on the vortex in the downstream smooth tube are studied for a range of high Reynolds numbers, where the existence of the corrugation part can turn out the secondary flow and enhance heat transfer. Meanwhile, it is found that in the smooth part, the fluid flow part with whirling can reach a maximum length, even if the length of the corrugation part continuously increases. Thus a series of critical corrugation lengths can be obtained. This work can reveal the enhanced heat transfer mechanism of the hybrid smooth and spirally corrugated tube and be of interest to researchers in heat transfer issues of corrugated tubes.
Evaluation of selected methods of the heat transfer coefficient determination in fin-and-tube cross-flow heat exchangers
Authors: Bury Tomasz , Hanuszkiewicz Drapała Małgorzata
Published: November 2018

The work is a part of a thermodynamic analysis of a finned cross-flow heat exchanger of the liquid-gas type. The heat transfer coefficients on the liquid and the gas side and the area of the heat transfer are the main parameters describing such a device. The basic problem in computations of such heat exchangers is determination of the coefficient of the heat transfer from the finned surfaces to the gas. The differences in the heat transfer coefficient local values resulting from the non-uniform flow of mediums through the exchanger complicates the analysis additionally. Six Nusselt number relationships are selected as suitable for the considered heat exchanger, and they are used to calculate the heat transfer coefficient for the air temperature ranging from 10°C to 30°C and for the velocity values ranging from 2 m/s to 20 m/s. In the next step, the gas-side heat transfer coefficient is determined by means of numerical simulations using a numerical model of a repetitive fragment of the heat exchanger under consideration. Finally, the Wilson plot method is also used. The work focuses on an analysis of the in-house HEWES code sensitivity to the method of the heat transfer coefficient determination. The authors believe that the analysis may also be useful for the evaluation of different methods of the heat transfer coefficient computation.
An analysis of temperature distribution in solar photovoltaic module under various environmental conditions
Authors: Jaszczur Marek , Hassan Qusay , Teneta Janusz , Majewska Ewelina , Zych Marcin
Published: November 2018

The operating temperature of the photovoltaic module is an important issue because it is directly linked with system efficiency. The objective of this work is to evaluate temperature distribution in the photovoltaic module under different environmental conditions. The results shown that photovoltaic module operating temperature depends not only on the ambient temperature or solar radiation dependent but also depends on wind speed and wind direction. It is presented that the mounting conditions which are not taken into consideration by most of the literature models also play a significant role in heat transfer. Depends on mounting type an increase in module operating temperature in the range 10-15oC was observed which cause further PV system efficiency decrease of about 3.8-6.5 %.
Study of dust deposition and temperature impact on solar photovoltaic module
Authors: Jaszczur Marek , Hassan Qusay , Teneta Janusz , Styszko Katarzyna , Nawrot Weronika , Hanus Robert
Published: November 2018

This work investigates the effect of the dust deposition and temperature on the photovoltaic module working under varying environmental conditions. The impact of the module temperature caused by the dust deposition, as well as direct impact caused by the dust particle absorption, scattering and reflectance on module performance, has been analysed. Presented results showed that dust deposition even in desert free country Poland influences the module temperature and power output significant. The estimated join effect of dust deposition and temperature increase, on power loss after three-four days of natural dust exposure in the city environment, was about 0.32 and 0.37 point of percentage for the selected sunny and cloudy days while evaluated PV system efficiency was in the range 13.37-14.14%.
Tilt optimization of a double-glazed air solar collector prototype
Authors: Mzad Hocine , Otmani Abdessalam , Haouam Abdallah , Łopata Stanisław , Ocłoń Pawel
Published: November 2018

To understand usage of solar air collector there are factors that have influence on the performance. The goal of this paper is to investigate a solar air collector prototype in order to perform a performance optimization using the possible min imum of equations. The thermal efficiency, fluid outlet temperature, heat increase and heat losses of the collector are calculated depending on the collector geometry, fluid properties, fluid inlet temperature, air flow rate, solar insulation and ambient temperature. The calculations were performed using actual data of temperature, wind speed and the global-horizontal radiation Hh over the year 2011 at the international airport of Annaba city. Comparison of results reveals that optimal efficacy is obtained for south facing panels with an inclination angle ß comprised in the interval [15°, 35°]. These conditions provide a useful energy exceeding 4300 W and an efficiency of about 51 %.
Energy saving and optimum insulation thicknesses in building upgrading
Authors: Orzechowski Mateusz , Orzechowski Tadeusz
Published: November 2018

Heat pumps are classified as ecologically friendly heat-generating devices and are one of the most suitable solutions for improving energy efficiency in buildings. Systems based on such solutions replace conventional sources very well. Household sector is one of the major energy consumers, where energy is used mainly for space heating and providing hot water. To increase renewable energy consumption levels, it is necessary to take decisive actions aimed at energy modernization of existing buildings. Particular emphasis must be put on the use of renewable energy sources. A wide selection of insulation materials is available on the market, however proper technologies are required to apply those materials, especially for historical buildings. Therefore, while planning investment, a question must be answered what type of material should be used, and what costs that will generate. The paper presents simple methodology for calculating the optimal insulation thickness so that the costs of the thermo-modernization would be covered by savings in heating expenses, when bank loan for the project is available at fixed interest rate.
First and second order dual phase lag equation. Numerical solution using the explicit and implicit schemes of the finite difference method
Authors: Majchrzak Ewa , Mochnacki Bohdan
Published: November 2018

In the paper the different variants of the dual phase lag equation (DPLE) are considered. As one knows, the mathematical form of DPLE results from the generalization of the Fourier law in which two delay times are introduced, namely the relaxation time τqand the thermalization one τT. Depending on the order of development of the left and right hand sides of the generalized Fourier law into the Taylor series one can obtain the different forms of the DPLE. It is also possible to consider the others forms of equation discussed resulting from the introduction of the new variable or variables (substitution). In the paper a thin metal film subjected to a laser pulse is considered (the 1D problem). Theoretical considerations are illustrated by the examples of numerical computations. The discussion of the results obtained is also presented.
Numerical investigation of passive stabilization of the surface temperature using PCM and metal foam
Authors: Seredyński Mirosław
Published: November 2018

Stabilization of the temperature of PVs is of great importance, due to strong relation between operating temperature and its efficiency. Due to low thermal conductivity of PCM, intensification of heat transfer to the operating material is needed. The four fully passive PV’s temperature stabilization systems, based on the phase change material (PCM) are numerically investigated in this paper. Apart from the natural convection promotion, intensification of heat transfer is done with aluminium fins and aluminium foam. The simplified computational model based on the equilibrium formulation of energy transport equation, taking into account viscous and inertial fluid flow resistances in the porous material, is formulated and solved with the general purpose software - ANSYS Fluent. Proposed model is succesfully verified by comparing the results with available in literature numerical solutions.Simulations outcomes are presented, the temperature and liquid fraction distributions in proposed geometry configurations, temperature variations determined in selected points and averaged on the heated surface temperature plots. Presented results help to assign the best configuration.
The influence of adsorption chillers on CHP power plants
Authors: Sztekler Karol , Kalawa Wojciech , Stefański Sebastian , Krzywanski Jarosław , Grabowska Karolina , Sosnowski Marcin , Nowak Wojciech
Published: November 2018

The simultaneous production of electricity, heat and cooling, the so-called trigeneration, allows for substantial savings in the chemical energy of fuels. More efficient use of the primary energy contained in fuels translates into tangible earnings for power plants while reductions in the amounts of fuel burned, and of non-renewable resources in particular, certainly have a favourable impact on the natural environment. The main aim of the above-described project was to analyse the influence of use adsorption contacted to conventional CHP power plant. An adsorption chiller is an item of industrial equipment that is driven by low grade heat and intended to produce chilled water and desalinated water. Adsorption chillers ACH can by used for utilization heat from many industrial process where temperature medium is too low for use absorption chillers. In this article modelled the cycle of a conventional heat power plant integrated with an adsorption chiller-based plant. Multi-variant simulation calculations were performed using IPSEpro simulation software.
Posterior versus direct anterior approach in total hip arthroplasty: difference in patient-reported outcomes measured with the Forgotten Joint Score-12
Authors: Ozaki Yu , Baba Tomonori , Homma Yasuhiro , Ochi Hironori , Watari Taiji , Banno Sammy , Matsumoto Mikio , Kaneko Kazuo
Published: November 2018

Introduction: When the postoperative outcome of primary total hip arthroplasty (THA) was compared with the direct anterior approach (DAA) and the posterior approach (PA), there was no significant difference of the clinical outcome at 6 months to 1 year after surgery in many studies. This study was performed to compare the medium-term outcome of THA via the DAA or PA and clarify which approach achieves better quality of life (QOL).

Methods: We investigated 61 hips receiving primary THA (30 via DAA and 31 via PA), using hip function scores such as the Harris Hip Score (HHS) and patient-reported outcomes such as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS).

Results: The mean duration of postoperative follow-up was 36.8 months in the DAA group and 40.5 months in the PA group. There was no difference in preoperative or postoperative HHS between the two groups. Although there was no difference of postoperative WOMAC and JHEQ, the postoperative FJS-12 score was significantly higher in the DAA group than in the PA group (75.2 ± 15.9 versus 60.1 ± 24.4,p = 0.01).

Conclusion: When forgetting the artificial joint in daily life is the target, better QOL can be achieved by performing THA via the DAA.
Debora: Akzeptanz und Machbarkeit eines Schmerzkompetenz- und Depressionspräventionstrainings in der VMO
Authors: Korsch Sabrina , Köpnick Anne , Hampel Petra
Published: November 2018

Ziel der Studie Es herrscht ein zunehmender Bedarf an der Etablierung von Patientenschulungen bei chronischem Rückenschmerz und psychischer Komorbidität. Die vorliegende Studie fand im Setting der stationären verhaltensmedizinisch orthopädischen Rehabilitation (VMO) statt und untersuchte die Akzeptanz und Machbarkeit des kombinierten Schmerzkompetenz- und Depressionspräventionstrainings Debora im Vergleich von Interventions- zur Kontrollgruppe. Während die Interventionsgruppe das kombinierte kognitiv-behaviorale Training erhielt, nahmen Rehabilitanden der Kontrollgruppe lediglich am Schmerzkompetenztraining teil.

Methodik Insgesamt wurden 3 Teilstudien für die formative Evaluation herangezogen. Das triangulative Design setzte sich aus problemzentrierten Interviews und Fokusgruppen mit Rehabilitanden sowie Fokusgruppen mit Experten zusammen. Die Interviews wurden transkribiert, anonymisiert und anschließend inhaltsanalytisch ausgewertet.

Ergebnisse Sowohl aus Rehabilitanden- als auch aus Expertenperspektive lag eine gute Akzeptanz und Machbarkeit des Trainings vor. Die durchführenden Therapeuten hatten bedeutsamen Einfluss auf die Teilnehmerzufriedenheit. Verbesserungswünsche gab es hauptsächlich zum Ausbau von Inhalten zur Schmerz- und Stressbewältigung sowie hinsichtlich der Beratung der individuellen Problemlagen. Die Kontrollgruppe bewertete das Training, unabhängig von der Depressivität, insgesamt schlechter und wies verglichen mit der Interventionsgruppe eine schlechtere Gruppenkohärenz auf.

Schlussfolgerung Die Ergebnisse der formativen Evaluation sprechen für die kombinierte Durchführung des Schmerzkompetenz- und Depressionspräventionstrainings Debora und legen die langfristige Etablierung des Trainings in der stationären VMO nahe.
An Opinion Survey of Orthopaedic and Traumatology Surgeons Working in Outpatient Care (Society, Laws and Patients)
Authors: Omari Ehsan , Thoma Wolfgang , Schulze Johannes
Published: November 2018

Background The German health care system is well accepted, but efficiency, costs and patient satisfaction are sometimes criticised. Opinions and models prevail, and empirical data are rarely presented, although quantitative data are a precondition to assess the acceptance of the health care system.

Method To determine the appraisal of the patient-doctor relationship, economic situation and cooperation with clinical institutions, a 37 item was developed where participants indicated their agreement with a statement on a four point Likert scale. This questionnaire was answered by 525 German orthopaedic and/or traumatology surgeons, representing 7.7% of all German specialists working in outpatient care.

Results 75% of all respondents felt challenged by demanding patients and a need for justification; what was less pronounced was the feeling of being exploited as physicians. Restrictions in medical treatment from budgeting expenses were seen by 74%. More than 90% considered that it was impossible to finance their medical practice expenses by conservative medical treatment only. The respondents felt similarly critical about the current cooperation with hospitals – only 19% were not interested in closer cooperation and 96% advocated higher fees for this cooperation. 74% confirmed that hospitals are taking over outpatient tasks, whereas only 35% agreed that more clinical patient care can be provided by outpatient providers, especially due to legal restrictions.

Discussion Practitioning orthopaedic and traumatology surgeons feel exploited by uninformed patients, misallocation of reimbursement funds and legal restrictions, as well as unilateral substitution of outpatient care by hospitals. They do not consider that the current structures are sustainable for long term patient care.
Body Composition and Strength Parameters in Elite Judo Athletes 5 Years after Anterior Cruciate Ligament Reconstruction
Authors: Prill Robert , Michel Sven , Schulz Robert , Coriolano Hans-Joachim
Published: November 2018

The purpose of this study was to investigate if there are still deficits in muscle mass or strength capabilities in elite judo athletes with a history of anterior cruciate ligament reconstruction (ACLR) after their return to the sport. Therefore, bioimpedance analysis, 3D-laser thigh circumference measurement and isokinetic dynamometry in a closed kinetic chain were used. The side-to-side differences were investigated in a group of judo athletes 5 years after ACLR (n=17) and compared with a group of healthy judo athletes (n=27). Neither thigh circumferences, nor muscle masses of the lower extremities differed in formerly injured judo athletes compared to healthy judo athletes. In contrast, isokinetic strength testing showed a significantly larger side-to-side difference of peak muscle force in formerly injured judo athletes (p=0.021). They provided significantly lower peak forces with the formerly injured leg than with the non-injured leg (p<0.001). The authors conclude that strength capabilities, but not body composition, remains altered in recovered judo athletes in mean 5 years after ACLR and definitely after their return to sports. This indicates that the focus of rehabilitation protocols and return to sports assessments should focus more on maximum strength capabilities.
Retrospective Analysis of Whole-Body Magnetic Resonance Imaging of Bone Manifestations in Long-Term Treated Patients with Gaucher Disease Type 1
Authors: Lollert André , Laudemann Katharina , Mengel Eugen , Hoffmann Christian , Moos Larissa , Reinke Jörg , Brixius-Huth Miriam , Hennermann Julia , Düber Christoph , Staatz Gundula
Published: November 2018

Purpose We retrospectively assessed bone and visceral manifestations in patients with Gaucher disease type 1 (GD1) with whole-body magnetic resonance imaging (WB-MRI) to determine the effects of different timing in initiating long-term enzyme replacement therapy.

Materials and Methods In 17 patients with GD1, we performed 2 WB-MRI examinations at a median interval of 13 months. Patients had received enzyme replacement therapy with alglucerase/imiglucerase for a median of 13 years prior to the first examination. MRI results were retrospectively stratified based on treatment initiation into 2 groups: “early” (age ≤12 years, median 5 years) and “late” (during adulthood, median 32 years). We evaluated occurrence of irreversible avascular necroses (AVN) and applied several semi-quantitative scores, including the Bone-Marrow-Burden (BMB) score, the Düsseldorf-Gaucher score (DGS), the Vertebra-Disc-Ratio (VDR), and the Gaucher disease type 1 Severity Scoring System (GD-DS3).

Results MRI assessments showed no AVN in the “early” group. AVN were observed in 2 patients of the “late” group; one also had a splenic Gaucheroma. The follow-up examinations showed slight improvements in the BMB-score, DGS, and VDR, with similar tendencies in both treatment groups. The GD-DS3 score only improved in “late” group.

Conclusion This retrospective study supported the ongoing clinical value of enzyme replacement therapy with alglucerase/imiglucerase, as WB-MRI-based scores stayed constant or slightly improved even after long-term treatment. Secondary complications were only observed in the late treatment group. Our results suggest that “early initiation” of enzyme replacement therapy may protect the bone.
Natural Deep Eutectic Solvents as Sustainable Solvents for Suzuki­–Miyaura Cross-Coupling Reactions Applied to Imidazo-Fused Heterocycles
Authors: Delaye Pierre-Olivier , Pénichon Mélanie , Boudesocque-Delaye Leslie , Enguehard-Gueiffier Cécile , Gueiffier Alain
Published: November 2018

Herein, we present the first Suzuki–Miyaura cross-coupling in a sustainable natural deep eutectic solvent (NaDES) applied to biologically relevant imidazo-fused scaffolds imidazo[1,2-a]pyridine and imidazo[1,2-b]pyridazine. The choline chloride/glycerol (1:2, mol/mol) NaDES allowed the functionalisation of diverse positions on the heterocycles with various boronic acids, by using 2.5 mol% of readily available Pd(OAc)2. Notably, the catalytic system proceeds without any ligands or additives, without protection from the atmosphere.
Lemierre Syndrome: Clinical Update and Protocol for a Systematic Review and Individual Patient Data Meta-analysis
Authors: Sacco Clara , Zane Federica , Granziera Serena , Holm Karin , Creemers-Schild Dina , Hotz Michel-André , Turpini Elena , Valentini Adele , Righini Christian , Karkos Petros , Verhamme Peter , Di Nisio Marcello , Konstantinides Stavros , Pecci Alessandro , Barco Stefano ,   on behalf of the Lemierre Study Group
Published: November 2018

Lemierre syndrome usually affects otherwise healthy adolescents or young adults and occurs at an overall rate of 1 to 10 cases per million person-years with an estimated fatality rate of 4 to 9%. Diagnostic criteria remain debated and include acute neck/head bacterial infection (often tonsillitis caused by anaerobes at high potential for sepsis and vascular invasion, notably Fusobacterium necrophorum) complicated by local vein thrombosis, usually involving the internal jugular vein, and systemic septic embolism. Medical treatment is based on antibiotic therapy with anaerobic coverage, anticoagulant drugs and supportive care in case of sepsis. Surgical procedures can be required, including drainage of the abscesses, tissue debridement and jugular vein ligation. Evidence for clinical management is extremely poor in the absence of any adequately sized study with clinical outcomes. In this article, we illustrate two cases of Lemierre syndrome not caused by Fusobacterium necrophorum and provide a clinically oriented discussion on the main issues on epidemiology, pathophysiology and management strategies of this disorder. Finally, we summarize the study protocol of a proposed systematic review and individual patient data meta-analysis of the literature. Our ongoing work aims to investigate the risk of new thromboembolic events, major bleeding or death in patients diagnosed with Lemierre syndrome, and to better elucidate the role of anticoagulant therapy in this setting. This effort represents the starting point for an evidence-based treatment of Lemierre syndrome built on multinational interdisciplinary collaborative studies.
The Mutual Relation of Platelet Activation and Innate Immunity
Authors: Eisinger Felix , Langer Harald
Published: November 2018

Platelets are known to be central regulators of haemostasis, inflammation and immune response. Formed by megakaryocytes in the bone marrow and the lungs, platelets express a broad range of adhesion receptors and release cytokines and platelet microparticles which enable them to interact with both immune cells and pathogens. In bacterial and viral infections, thrombophilia and thrombocytopenia are commonly seen symptoms, indicating the close relationship between haemostasis and immune defence. Indeed, platelets contribute both directly and via immune mediation to pathogen clearance. In sterile inflammation, a pathogen-free process which is often triggered by cell necrosis and autoimmune reactions, platelets are also of central importance. Recently, platelet inflammasome has been extensively studied in this context. Both sterile inflammation and infection are affected by the interactions of platelets and innate immunity, notably the complement system. Although the general elements of this interplay have been known for long, more and more insights into disease-specific mechanisms could be gained recently. This review gives an outline of the current findings in the field of platelet–immune cell interactions and points out possible implications for clinical therapy.
Future Antithrombotic Therapies in Cardiology
Authors: Bäuml Marina , Hilgendorf Ingo
Published: November 2018

Thrombi are composed of activated platelets and fibrin, the latter being the final product of the blood coagulation system. Therefore, antithrombotic therapies may either interfere with adhesion, aggregation, secretion or signalling of platelets or with fibrin formation. Established drugs potently inhibit clot formation, but also increase the risk of bleeding. In this review article, we discuss novel strategies for the inhibition of pathological thrombosis while enabling normal haemostasis, thus minimizing the risk of bleeding.
Aortomegaly Causing Nutcracker Syndrome and Pelvic Congestion Syndrome
Authors: Rathod Krantikumar , Sahu Amit , Popat Bhavesh , Deshmukh Hemant
Published: November 2018

The authors present an uncommon cause of pelvic congestion syndrome (PCS) secondary to anterior nutcracker syndrome, which was caused by aortomegaly. Positional flank and pelvic pain was the only presenting feature with no renal dysfunction. Early and significant decompression of left renal vein (LRV) via left ovarian vein resulted in preserved renal function with symptomatic pelvic varices. Endovascular management by left ovarian vein coiling and LRV stenting was done. They briefly review the etiopathology, imaging, treatment rationale, and management options for nutcracker and PCS.
Shielding of the azimuthal magnetic field by the anode plasma in a relativistic self-magnetic-pinch diode
Authors: Biswas S. , Johnston M. D. , Doron R. , Mikitchuk D. , Maron Y. , Patel S. G. , Kiefer M. L. , Cuneo M. E.
Published: November 2018

In relativistic electron beam diodes, the self-generated magnetic field causes electron-beam focusing at the center of the anode. Generally, plasma is formed all over the anode surface during and after the process of the beam focusing. In this work, we use visible-light Zeeman-effect spectroscopy for the determination of the magnetic field in the anode plasma in the Sandia 10 MV, 200 kA (RITS-6) electron beam diode. The magnetic field is determined from the Zeeman-dominated shapes of the Al III 4s–4p and C IV 3s–3p doublet emissions from various radial positions. Near the anode surface, due to the high plasma density, the spectral line-shapes are Stark-dominated, and only an upper limit of the magnetic field can be determined. The line-shape analysis also yields the plasma density. The data yield quantitatively the magnetic-field shielding in the plasma. The magnetic-field distribution in the plasma is compared to the field-diffusion prediction and found to be consistent with the Spitzer resistivity, estimated using the electron temperature and charge-state distribution determined from line intensity ratios.
Bayesian calibration of strength parameters using hydrocode simulations of symmetric impact shock experiments of Al-5083
Authors: Walters David J. , Biswas Ayan , Lawrence Earl C. , Francom Devin C. , Luscher Darby J. , Fredenburg D. Anthony , Moran Kelly R. , Sweeney Christine M. , Sandberg Richard L. , Ahrens James P. , Bolme C. A.
Published: November 2018

Predictive modeling of materials requires accurately parameterized constitutive models. Parameterizing models that describe dynamic strength and plasticity require experimentally probing materials in a variety of strain rate regimes. Some experimental protocols (e.g., plate impact) probe the constitutive response of a material using indirect measures such as free surface velocimetry. Manual efforts to parameterize constitutive models using indirect experimental measures often lead to non-unique optimizations without quantification of parameter uncertainty. This study uses a Bayesian statistical approach to find model parameters and to quantify the uncertainty of the resulting parameters. The technique is demonstrated by parameterizing the Johnson-Cook strength model for aluminum alloy 5083 by coupling hydrocode simulations and velocimetry measurements of a series of plate impact experiments. Simulation inputs and outputs are used to calibrate an emulator that mimics the outputs of the computationally intensive simulations. Varying the amount of experimental data available for emulator calibration showed clear differences in the degree of uncertainty and uniqueness of the resulting optimized Johnson-Cook parameters for Al-5083. The results of the optimization provided a numerical evaluation of the degree of confidence in model parameters and model performance. Given an understanding of the physical effects of certain model parameters, individual parameter uncertainty can be leveraged to quickly identify gaps in the physical domains covered by completed experiments.
Electronic transport and Klein tunneling in gapped AA-stacked bilayer graphene
Authors: Abdullah Hasan M. , Al Ezzi Mohammed , Bahlouli H.
Published: November 2018

We theoretically investigate the electronic transport and Klein tunneling in AA-stacked bilayer graphene (AA-BLG) encapsulated by dielectric materials. Using the four-band continuum model, we evaluate the transmission and reflection probabilities along with the respective conductances. We find that the interlayer mass-term difference induced by the dielectric materials opens a gap in the energy spectrum and couples the upper and lower Dirac cones in AA-BLG. This cone coupling induces an inter-cone transport that is asymmetric with respect to the normal incidence in the presence of the asymmetric mass-term. The energy spectrum of the gapped AA-BLG exhibits electron-hole asymmetry that is reflected in the associated intra- and inter-cone transport channels. We also find that even though Klein tunneling exists in gated and biased AA-BLG, it is precluded by the interlayer mass-term difference and instead Fabry-Pérot resonances appear.
All group-IV SiGeSn/GeSn/SiGeSn QW laser on Si operating up to 90 K
Authors: Margetis Joe , Zhou Yiyin , Dou Wei , Grant Perry C. , Alharthi Bader , Du Wei , Wadsworth Alicia , Guo Qianying , Tran Huong , Ojo Solomon , Abernathy Grey , Mosleh Aboozar , Ghetmiri Seyed A. , Thompson Gregory B. , Liu Jifeng , Sun Greg , Soref Richard , Tolle John , Li Baohua , Mortazavi Mansour , Yu Shui-Qing
Published: November 2018

In this work, all group-IV band-to-band lasers based on SiGeSn/GeSn/SiGeSn multi-quantum-well structures were demonstrated. Lasing performance was investigated via two 4-well samples. The thinner GeSn well sample exhibits a maximum lasing temperature of 20 K and a threshold of 55 kW/cm2 at 10 K, while the thicker well sample features a higher maximum operating temperature of 90 K and lower lasing thresholds of 25 and 62 kW/cm2 at 10 and 77 K, respectively. The distinct results were tentatively interpreted mainly by the difference of gain volume. This result provides guidance for the future GeSn quantum well laser optimization for higher performance.
Optimized rotation of an optically trapped particle for micro mixing
Authors: Hosseinzadeh Mahmoud , Hajizadeh Faegheh , Habibi Mehdi , Milani Moghaddam Hossain , S. Reihani S. Nader
Published: November 2018

The angular momentum transferred by circularly polarized photons is able to rotate an optically trapped microparticle. Here, the optically rotating particle is introduced as an active micromixer to reduce the mixing time in a microfluidic system. To optimize the system for microfluidic application, the effect of several optical parameters such as spherical aberration and the numerical aperture of the objective on the rotation rate of a trapped particle is investigated. The results show that the optimized depth for the rotation of a particle is located close to the coverslip and can be changed by a fine adjustment of the refractive index of the immersion oil. By applying the obtained optimized optical parameters on a trapped particle at the interface of two fluids in a microchannel, the mixing length is reduced by a factor of ∼2.
Numerical simulation for a rising bubble interacting with a solid wall: Impact, bounce, and thin film dynamics
Authors: Zhang Changjuan , Li Jie , Luo Li-Shi , Qian Tiezheng
Published: November 2018

Using an arbitrary Lagrangian-Eulerian method on an adaptive moving unstructured mesh, we carry out numerical simulations for a rising bubble interacting with a solid wall. Driven by the buoyancy force, the axisymmetric bubble rises in a viscous liquid toward a horizontal wall, with impact on and possible bounce from the wall. First, our simulation is quantitatively validated through a detailed comparison between numerical results and experimental data. We then investigate the bubble dynamics which exhibits four different behaviors depending on the competition among the inertial, viscous, gravitational, and capillary forces. A phase diagram for bubble dynamics has been produced using the Ohnesorge number and Bond number as the two dimensionless control parameters. Finally, we turn to the late stage of the bubble rise characterized by a small flux of liquid escaping from the thin film between the wall and the bubble. Since the thin film dynamics can be accurately described by the lubrication approximation, we carry out numerical simulations to compare the simulation results with the predictions of the lubrication approximation. Remarkable agreement is obtained to further demonstrate the accuracy of the simulations.
High-mobility diamond field effect transistor with a monocrystalline h-BN gate dielectric
Authors: Sasama Yosuke , Komatsu Katsuyoshi , Moriyama Satoshi , Imura Masataka , Teraji Tokuyuki , Watanabe Kenji , Taniguchi Takashi , Uchihashi Takashi , Takahide Yamaguchi
Published: November 2018

Diamond is a wide bandgap semiconductor that can work at high temperatures and resist very high electric fields. It endures harsh environments through its physical stability and conducts heat very well. These properties make diamond suitable for the fabrication of unique electronic devices. In particular, diamond field effect transistors (FETs) have promising applications, including high-power converters for trains and electric vehicles and high-power high-frequency amplifiers for telecommunications and radar. Although high mobility is desirable for these applications, it has been difficult to achieve in diamond FETs particularly when the carrier density is high. The low mobility is most probably due to fixed and trapped charges in the non-ideal amorphous gate dielectric and at the dielectric/diamond interface. Here, we report on diamond FETs with monocrystalline hexagonal boron nitride (h-BN) as a gate dielectric. Thanks to the low density of charged impurities in monocrystalline h-BN, we obtained unprecedentedly high mobilities (>300 cm2 V−1 s−1) for moderately high carrier densities (>5 × 1012 cm−2). The resulting minimum sheet resistance was exceptionally low (<3 kΩ). Our results show that a heterostructure consisting of monocrystalline h-BN and diamond is an excellent platform with which to manufacture high-performance electronic devices.
High-density cascade arc plasma sources for application to plasma windows for virtual vacuum interfaces
Authors: Namba S. , Iwamoto Y. , Asano Y. , Shugyo T. , Fukuyama K. , Ikoma N. , Okuno H. , Tamura N. , Endo T.
Published: November 2018

We develop two cascade arc plasma sources for application to plasma windows for virtual vacuum interfaces. For windowless vacuum–atmosphere separation, a compact arc discharge source having a channel diameter of 3 mm is fabricated, and an atmospheric Ar thermal plasma is generated. For an alternative differential pumping system, separating low- and high-pressure vacuum chambers, a larger arc device with an 8-mm diameter is also constructed, producing a high-density He plasma. The performances of the two cascade arcs as plasma windows are investigated. The 3-mm arc discharge generates a steep pressure gradient of Ar 100 kPa–100 Pa through the discharge channel, while the 8-mm discharge apparatus isolates the high-pressure side at 7 kPa from the lower pressure of 54 Pa. Emission spectroscopy of visible and vacuum UV radiation reveals the characteristics of the Ar and He plasmas. Spectral analysis yields a plasma temperature of around 1 eV in both discharges. Stark broadenings of the H-β and Ar I lines give an electron density of 6.5 × 1016 cm−3 for Ar 60 A with a gas flow rate of 1.0 l/min and 4.7 × 1013 cm−3 under a He 100-A and 0.45-l/min condition.
The traditional livestock breeding practices of women and men Somali pastoralists: breeding management and beliefs on breeding issues
Authors: Marshall Karen , Mtimet Nadhem , Wanyoike Francis , Ndiwa Nicholas , Ghebremariam Haileselassie , Mugunieri Lawrence , Costagli Riccardo
Published: November 2018

In Somalia, located in the horn of Africa and one of the world’s poorest countries, livestock are the mainstay of the economy. While strengthening the livestock sector is considered key to reduced poverty and increased food security, few studies have reported the livestock management practices of Somali pastoralists, including on breeding issues. Here, we present the final of a series of papers documenting the breeding practices of women and men Somali pastoralists for goat, sheep, camel and cattle. Data for the study were obtained by surveying 200 livestock-keeping households located within the Tog-Dheer region of Somaliland. The most important livestock species kept, in terms of contribution to household livelihood, were goats and sheep, followed by camel, then cattle. Migration with livestock was practiced by two-thirds of the households for some or all of the year, whereas other households were settled with their livestock. On breeding practices, the main means of acquiring breeding animals was by the animal being born into the herd, and varied means were used to control mating, including castration, culling, separation of male and female animals, purposeful mating of best males to best females, and controlling the size of mating groups. On beliefs on breeding issues, the pastoralists had a varied understanding of whether specific livestock traits were influenced by genetics, environment, or a combination of both, and most could not articulate the basis of inheritance. Knowledge of inbreeding was poor, with almost all respondents indicating they did not consider the mating of related animals to be problematic. Additionally, some pastoralists tried to influence the sex of the livestock progeny born through various practices. Overall, the finding presented here and in the companion studies (Marshall et al. 2014, 2016) indicated that the women and men Somali pastoralists generally employ sound breeding practices, although there is room for capacity building such as on inbreeding.
Metabolic network-based stratification of hepatocellular carcinoma reveals three distinct tumor subtypes
Authors: Bidkhori Gholamreza , Benfeitas Rui , Klevstig Martina , Zhang Cheng , Nielsen Jens , Uhlen Mathias , Boren Jan , Mardinoglu Adil
Published: November 2018

Significance

Hepatocellular carcinoma (HCC) is a heterogeneous and deadly form of liver cancer. Here, we stratified and characterized HCC tumors by applying graph and control theory concepts to the topology of genome-scale metabolic networks. We identified three HCC subtypes with distinct differences in metabolic and signaling pathways and clinical survival and validated our results by performing additional experiments. We further identified HCC subtype-specific genes pivotal in controlling the entire metabolism and discovered genes that can be targeted for development of efficient treatment strategies for specific HCC subtypes. Our systems-level analyses provided a systematic way for characterization of HCC subtypes and identification of drug targets for effective treatment of HCC patients.
NETSeq reveals heterogeneous nucleotide incorporation by RNA polymerase I
Authors: Clarke Andrew M. , Engel Krysta L. , Giles Keith E. , Petit Chad M. , Schneider David A.
Published: November 2018

Significance

It is well known that ribosomal RNA processing is directly impacted by the rate of transcription elongation by RNA polymerase I (Pol I). To understand how these processes are orchestrated, we must carefully define transcription elongation properties in vitro and in living cells. Here, we characterize DNA sequence elements that pause and terminate Pol I transcription in vitro. We also establish methods for analyzing Pol I transcription elongation properties in vivo using native elongating transcript sequencing (NETSeq). Our NETSeq data revealed frequent pausing by Pol I and decreased Pol I occupancy at G residues, suggesting unequal rates of nucleotide incorporation by the enzyme. These findings redefine our understanding of Pol I transcription elongation and its heterogeneity in vivo.
Structure and architecture of immature and mature murine leukemia virus capsids
Authors: Qu Kun , Glass Bärbel , Doležal Michal , Schur Florian K. M. , Murciano Brice , Rein Alan , Rumlová Michaela , Ruml Tomáš , Kräusslich Hans-Georg , Briggs John A. G.
Published: November 2018

Retroviruses assemble and bud from infected cells in an immature form and require proteolytic maturation for infectivity. The CA (capsid) domains of the Gag polyproteins assemble a protein lattice as a truncated sphere in the immature virion. Proteolytic cleavage of Gag induces dramatic structural rearrangements; a subset of cleaved CA subsequently assembles into the mature core, whose architecture varies among retroviruses. Murine leukemia virus (MLV) is the prototypical γ-retrovirus and serves as the basis of retroviral vectors, but the structure of the MLV CA layer is unknown. Here we have combined X-ray crystallography with cryoelectron tomography to determine the structures of immature and mature MLV CA layers within authentic viral particles. This reveals the structural changes associated with maturation, and, by comparison with HIV-1, uncovers conserved and variable features. In contrast to HIV-1, most MLV CA is used for assembly of the mature core, which adopts variable, multilayered morphologies and does not form a closed structure. Unlike in HIV-1, there is similarity between protein–protein interfaces in the immature MLV CA layer and those in the mature CA layer, and structural maturation of MLV could be achieved through domain rotations that largely maintain hexameric interactions. Nevertheless, the dramatic architectural change on maturation indicates that extensive disassembly and reassembly are required for mature core growth. The core morphology suggests that wrapping of the genome in CA sheets may be sufficient to protect the MLV ribonucleoprotein during cell entry.
Coordinated histone modifications and chromatin reorganization in a single cell revealed by FRET biosensors
Authors: Peng Qin , Lu Shaoying , Shi Yuxin , Pan Yijia , Limsakul Praopim , Chernov Andrei V. , Qiu Juhui , Chai Xiaoqi , Shi Yiwen , Wang Pengzhi , Ji Yanmin , Li Yi-Shuan J. , Strongin Alex Y. , Verkhusha Vladislav V. , Izpisua Belmonte Juan Carlos , Ren Bing , Wang Yuanliang , Chien Shu , Wang Yingxiao
Published: November 2018

Significance

We have developed a fluorescence resonance energy transfer (FRET) biosensor to visualize in single live cells the histone H3 Lys-9 trimethylation (H3K9me3) dynamics. Together with another FRET biosensor for simultaneous monitoring of the neighboring histone H3 Ser-10 phosphorylation (H3S10p) in the same cell, we found an anticorrelation between the dynamics of H3K9me3 and H3S10p during cell cycles, with H3S10p facilitating the decrease of H3K9me3 at onset of mitosis. This decrease of H3K9me3 is accompanied by dissolution of heterochromatin structures before chromatin condensation and nuclear envelope dissolution. The coordinated regulation of H3S10p and H3K9me3 may enhance access of remodeling complexes to the chromatin. Our results hence provide insights on how histone modifications and chromatin structures are coordinated to regulate mitosis.
Bottom–up modeling of chromatin segregation due to epigenetic modifications
Authors: MacPherson Quinn , Beltran Bruno , Spakowitz Andrew J.
Published: November 2018

Significance

Predicting how epigenetic marks control the 3D organization of the genome is key to understanding how these marks regulate gene expression. We show that a physical model of a chromosome with experimentally measured local interactions segregates into euchromatin- and heterochromatin-like phases. The model reproduces many of the features of the large-scale organization of the chromosome as measured by Hi-C. Our work provides an estimate of the amount of epigenetic marking needed to segregate a gene into heterochromatin.