bluuebunny/crossref_metadata_2025 huggingface dataset:
Hysterectomy for Cervical and Intraligamental Fibroids
Authors: Hiramatsu Yuji
Published: November 2019

Hysterectomy for cervical and intraligamental fibroids is particularly likely to cause massive bleeding, ureteral/bladder injury, and intestinal damage. In such cases, preoperative evaluation is very important, and the way in which surgery proceeds should be based on the preoperative evaluation findings. In other words, before starting surgery, it is important to discuss what second and third methods to use if the first surgical method is unsuccessful. The main points to consider during surgery are expanding the operative field, approaching the operation from a site with weak adhesions, and performing applied techniques such as myomectomy and retrograde hysterectomy.
Evaluation of Obesity Influence in the Sexual Function of Postmenopausal Women: A Cross-Sectional Study
Authors: Silva Gustavo Maximiliano Dutra da , Lima Sônia Maria Rolim Rosa , Reis Benedito Fabiano dos , Macruz Carolina Furtado , Postigo Sóstenes
Published: November 2019

Objective The incidence of obesity, which is a chronic condition, has increased in recent years. The association between obesity and female sexual dysfunction remains unclear, particularly in postmenopausal women. In the present study, we evaluated whether obesity is a risk factor for sexual dysfunction in postmenopausal women.

Methods This is a cross-sectional study that analyzed data from interviews of postmenopausal women at the Climacteric Outpatient Clinic from 2015 to 2018. After applying the inclusion and exclusion criteria, 221 women aged between 40 and 65 years old were selected and invited to participate in the study. Obesity was diagnosed according to body mass index (BMI). The participants were grouped into the following BMI categories: group 1, 18.5–24.9 kg/m2 (normal); group 2, 25.0–29.9 kg/m2 (overweight); and group 3, ≥30.0 kg/m2 (obese). Sexual function was assessed using the Female Sexual Function Index (FSFI) questionnaire. Cutoff points of ≥23 and ≥26.5 were adopted to define a diagnosis of female sexual dysfunction (FSD) based on the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, Text Revision by the American Psychiatric Association (DSM-IV-TR).

Results The desire and arousal scores were statistically higher in the normal BMI group than in the obese group (p = 0.028 and p = 0.043, respectively). The satisfaction scores were statistically higher in the normal BMI group than in the overweight and obese groups (p < 0.05). The total FSFI score statistically differed among the BMI categories (p = 0.027).

Conclusion In the present study, obese and overweight postmenopausal women had higher total scores than women with normal BMI. Our results show that obese and overweight postmenopausal women had a higher index of dysfunction in desire and arousal and lower sexual satisfaction than normal-weight women.
Organization of a Neurointensive Care Unit
Authors: Chavali Siddharth , Sidiqqi Obaid A. , Rath Girija P.
Published: November 2019

Although in its infancy as a specialty, neurocritical care is rapidly developing its own niche, with a wide profile of patients—both neurosurgical and those with neurological pathologies. Rapid advances in monitoring technology as well as surgical techniques have led to an increasing number of patients, often presenting with myriad concurrent illnesses, who could be best served if managed by specialist neurointensivists. Neurocritical care units are being developed as free-standing intensive care units in several tertiary care hospitals, and literature regarding their establishment and organization is scant, leading to questions regarding how best to utilize resources to gain maximum benefit. This review aims to outline the challenges that are likely to be faced during establishment of such a unit, and to identify certain issues that are specific to this specialty.
Thalidomide Reduces Cell Proliferation in Endometriosis Experimentally Induced in Rats
Authors: Antônio Luana Grupioni Lourenço , Rosa-e-Silva Julio Cesar , Machado Deborah Juliani , Westin Andrezza Telles , Garcia Sergio Britto , Candido-dos-Reis Francisco José , Poli-Neto Omero Benedicto , Nogueira Antonio Alberto
Published: November 2019

Objective To analyze the effect of thalidomide on the progression of endometriotic lesions experimentally induced in rats and to characterize the pattern of cell proliferation by immunohistochemical Proliferating Cell Nuclear Antigen (PCNA) labeling of eutopic and ectopic endometrium.

Methods Fifteen female Wistar rats underwent laparotomy for endometriosis induction by resection of one uterine horn, isolation of the endometrium and fixation of a tissue segment to the pelvic peritoneum. Four weeks after, the animals were divided into 3 groups: control (I), 10mg/kg/day (II) and 1mg/kg/day (III) intraperitoneal thalidomide for 10 days. The lesion was excised together with the opposite uterine horn for endometrial gland and stroma analysis. Eutopic and ectopic endometrial tissue was submitted to immunohistochemistry for analysis of cell proliferation by PCNA labeling and the cell proliferation index (CPI) was calculated as the number of labeled cells per 1,000 cells.

Results Group I showed a mean CPI of 0.248 ± 0.0513 in the gland and of 0.178 ± 0.046 in the stroma. In contrast, Groups II and III showed a significantly lower CPI, that is, 0.088 ± 0.009 and 0.080 ± 0.021 for the gland (p < 0.001) and 0.0945 ± 0.0066 and 0.075 ± 0.018 for the stroma (p < 0.001), respectively. Also, the mean lesion area of Group I was 69.2 mm2, a significantly higher value compared with Group II (49.4 mm2, p = 0.023) and Group III (48.6 mm2, p = 0.006). No significant difference was observed between Groups II and III.

Conclusion Thalidomide proved to be effective in reducing the lesion area and CPI of the experimental endometriosis implants both at the dose of 1 mg/kg/day and at the dose of 10 mg/kg/day.
Pulmonary Edema in the Acute Stage of Rheumatic Fever Treated with Double-Valve Replacement in a Pediatric Patient
Authors: Yozgat Yilmaz , Uzuner Selcuk , Yesilbas Osman , Ogur Mustafa , Yakut Kahraman , Yozgat Can Yilmaz , Temur Hafize Otcu , Ay Yasin
Published: November 2019

Cardiogenic pulmonary edema (CPE) is a rare clinical condition of acute rheumatic fever (ARF) in the early stage. Generally, CPE can be convalesced by steroid and anticongestive treatment. Herein, we describe a case of a 14-year-old boy with ARF presenting with bilateral pulmonary edema secondary to acute mitral and aortic insufficiency. In this case, the pulmonary edema of ARF was successfully managed by combined surgical replacements of both valves.
Terahertz hyper-Raman time-domain spectroscopy of gallium selenide and its application in terahertz detection
Authors: Mou Sen , Rubano Andrea , Paparo Domenico
Published: November 2019

We report the observation of Terahertz (THz) hyper-Raman generation in a gallium selenide crystal. This nonlinear optical process derives from the four- and five-wave-mixing of femtosecond optical pulses and intense, subps, broadband terahertz pulses. The wavelength spectrum of the resulting signal displays two pronounced frequency sidebands close to the optical second-harmonic central frequency 2ωL, where ωL is the optical central frequency of the fundamental beam. The two sidebands develop around the central frequency at the (anti-) Stokes side of ωs,a=2ωL∓ωT, where ωT is the THz central frequency. This nonlinear optical process is used for the coherent detection of intense and broadband terahertz waves. The proposed technique shows a good linear response of up to 90 kV/cm and a better efficiency in detecting the lowest terahertz frequencies, as compared to the standard electro-optic sampling performed in two different nonlinear crystals.
Dynamic pilot wave bound states
Authors: Shinbrot Troy
Published: November 2019

Motivated by recent parallels between classical bouncing droplet experiments and quantum bound states, we explore the lessons that droplet experiments might teach us about the dynamics of quantum solutions. Since the classical experiment is periodically driven, we examine periodic driving of the integer spin Klein-Gordon equation. We find that an exact solution can be obtained, and surprisingly this solution necessarily produces “half-integer” orbital angular momentum. We stress that these findings are strictly mathematical; nevertheless, this and other physical implications are intriguing and suggest further study.
Relativistic effects on dust grain charging in non-equilibrium dusty plasma with relativistic Tsallis distribution
Authors: Taherimoghadam Masoud , Motie Iman , Bakhshayeshi Ali , Mirzaye Taghi
Published: November 2019

The relativistic effects on the dust grain charging are investigated by calculating the relativistic cross section by the orbit-limited motion (OLM) theory and relativistic Tsallis distribution function for currents carried by ions and electrons in nonequilibrium plasma. The dust grain electrical potential equation is derived in the dust grain charging process, and this nonlinear equation is solved by the numerical method. We indicate that the behavior of nonextensivity is in contrast to ions and electrons, and it is found that the density of species in plasma has the most influence on the degree of nonextensivity. We show that the degree of nonextensivity of the electron and the ion has significant effects on the relationship between dust grain electrical potential and dust density. As another result, it is indicated that by increasing the dust density, the dust particles will be seen as a component from ordinary multi-ionic plasma that shows collective behavior. By comparing the results in relativistic and nonrelativistic regimes, it is indicated that in the relativistic regime, the density of dust is limited, and the electrical potential of dust grains also varies, whereas in the nonrelativistic regime, the dust density is not limited, and the dust grain electrical potential tends to be constant in small amounts of dust density.
Study on flow fields of regional control constrained spray deposition under different atomization gas pressures
Authors: Chen Yegao , Yin Jiancheng
Published: November 2019

A regional control constrained spray deposition model was established to study the flow fields and deposition of atomized droplets in a semienclosed space. The FLUENT software was used to simulate the changing rules of the pressure field, velocity field, and temperature field under different atomization gas pressures (AGPs), aiming to optimize the equipment and parameters of spray Conform. The results show that the flow fields are prone to be disturbed by the controller of the two rotating disks when the AGP is low, which makes it difficult to control the droplet deposition. Besides, excessive AGP will bring a robust reverse airflow, which is not conducive to control droplet deposition either. However, the outlet pressure of the diversion tube is about 2.5 × 104 Pa when the AGP is between 2.5 and 3.0 × 105 Pa. In this condition, the melt will exit the nozzle without blockage. Moreover, the pressure near the basement is about 5 × 104 Pa at this point, making the droplet deposition controllable.
Numerical study on wide gap Taylor Couette flow with flow transition
Authors: Razzak M. A. , Khoo B. C. , Lua K. B.
Published: November 2019

This study aims to investigate the possible sources of nonaxisymmetric disturbances and their propagation mechanism in Taylor Couette flow for wide gap problems using a direct numerical simulation with a radius ratio of 0.5 and the Reynolds number (Re) ranging from 60 to 650. Here, attention is focused on the viscous layer (VL) thickness in near-wall regions and its spatial distribution along the axial direction to gain an insight into the origin and propagation of nonaxisymmetric disturbances. The results show that an axisymmetric Taylor-vortex flow occurs when Re is between 68 and 425. Above Re = 425, transition from axisymmetric to nonaxisymmetric flow is observed up to Re = 575 before the emergence of wavy-vortex flow. From the variation of VL thickness with Re, the VL does not experience any significant changes in the flow separation region of the inner wall, as well as jet impingement region of both the inner and outer walls. However, a sudden increase in VL thickness in the flow separation region of the outer wall reveals possible sources of nonaxisymmetric disturbances in the flow separation region of the outer wall. These disturbances develop into the periodic secondary flow as the axisymmetric flow transforms into nonaxisymmetric flow, and this leads to the emergence of the azimuthal wave. The periodic secondary flow contributes to a sudden increase in the natural wavelength and rapid reduction in the strength of two counter-rotating Taylor vortices. This in turn leads to a substantial reduction of torque in the transition flow vis-à-vis axisymmetric Taylor-vortex flow.
Anomalous viscoelastic response of water-dimethyl sulfoxide solution and a molecular explanation of non-monotonic composition dependence of viscosity
Authors: Kumar Shubham , Sarkar Sarmistha , Bagchi Biman
Published: November 2019

Amphiphilic molecules such as dimethyl sulfoxide (DMSO) and its aqueous binary mixtures exhibit pronounced nonideality in composition dependence of several static and dynamic properties. We carry out detailed molecular dynamics simulations to calculate various properties including viscosity of the mixture and combine the results with a mode coupling theory analysis to show that this nonideality can be attributed to local structures that are stable on a short time scale but transient on a long time scale to maintain the large scale homogeneity of the solution. Although the existence of such quasistable structures has been deciphered from spectroscopy, a detailed characterization does not exist. We calculate stress-stress autocorrelation functions (SACFs) of water-DMSO binary mixtures. We employ two different models of water, SPC/E and TIP4P/2005, to check the consistency of our results. Viscosity shows a pronounced nonmonotonic composition dependence. The calculated values are in good agreement with the experimental results. Fourier transform of SACF provides frequency-dependent viscosity. The frequency-dependent viscosity (that is, viscoelasticity) is also found to be strongly dependent on composition. Viscoelasticity exhibits sharp peaks due to intramolecular vibrational modes of DMSO, which are also seen in the density of states. We evaluate the wavenumber dependent dynamic structure factor and wavenumber dependent relaxation time. The latter also exhibits a sharp nonmonotonic composition dependence. The calculated dynamic structure factor is used in mode coupling theory expression of viscosity to obtain a semiquantitative understanding of anomalous composition dependence of viscosity. Both the self-diffusion coefficients and rotational correlation times of water and DMSO molecules exhibit nonmonotonic composition dependence.
Investigation of carrier localization in InAs/AlSb type-II superlattice material system
Authors: Lee S. , Jo H. J. , Mathews S. , Simon J. A. , Ronningen T. J. , Kodati S. H. , Fink D. R. , Kim J. S. , Winslow M. , Grein C. H. , Jones A. H. , Campbell J. C. , Krishna S.
Published: November 2019

We investigate carrier localization in the InAs/AlSb type-II superlattice (T2SL) material system using temperature- and excitation power (Iex)-dependent photoluminescence (PL). Evidence of carrier localization in T2SLs was observed by an S-shaped temperature dependence of the PL peak position. Analysis of the Iex-dependent PL at various temperatures also shows the existence of carrier localization in the T2SLs. The thermal activation energies in T2SLs were extracted to identify the nonradiative recombination mechanisms and the possible origins of localized states. We found that there are two thermal activation energies, E1 = 8.2–1.2 meV and E2 = ∼60 meV at various Iex. We interpret E1 as a thermal activation energy that comes from Anderson localization, associated with roughness due to As2 diffusion into the interfaces. This is because the extracted E1 values are comparable to the exciton binding energy of localization in various quantum structures. Carrier trapping at a state in the InSb interfacial layer (Tamm state) may account for the origin of E2. Based on previous reports, we believe that the 60 meV state might be a Tamm state if we consider thickness variations in the InSb interfacial layer for the T2SLs.
Modeling of vacuum arc plasmas in anode spot or anode plume mode taking into account multiple ion components
Authors: Yang Ze , Wang Lijun , Deng Jie , Jia Shenli
Published: November 2019

This work investigates the arc behaviors with CuCr25 electrodes considering anode vapor using a magneto-hydro-dynamic model. Different kinds of components are considered including ions (Cu and Cr) with different charge numbers, electrons, and atoms (Cu and Cr). The effect of the anode sheath is also considered. The density distributions of these components are analyzed and compared with the experiments during the anode spot mode and the anode plume mode. Simulation results show that the anode vapor can enter the arc column forming a cool and poorly conducting region (i.e., neutral atom vapor area, NAVA) under high anode temperature. Atoms and single-charged ions mainly gather near each electrode. The highest double-charged ion density can be seen in front of the NAVA. Triple-charged ion density is negligibly low and reaches its maximum where the electron temperature is high. Cr is more likely to be ionized to a higher ionization level compared with Cu. Our results agree with experimental measurements of density distributions of different components and plasma temperature.
Study of the compression behavior and high-pressure strength of a-Si3N4 combining experimental and theoretical methods
Authors: Jiang Mingli , Kou Zili , Liang Hao , Dou Xilong , Li Xin , Guan Shixue , Huo Ruizhi , Wang Zhiwei , Yin Xiaoshuang , Chen Shijiang , Peng Fang
Published: November 2019

The compression behavior and high-pressure strength of alpha silicon nitride (α-Si3N4) at pressures of up to 60 GPa are studied using synchrotron radiation powder diffraction, complemented with first-principles calculations. Compression experiments reveal that a-Si3N4 remains stable under the highest pressure and ambient temperature and has a bulk modulus of K0 = 256.3(±4) GPa, with a pressure derivative of K′0 = 5.6. However, the bulk modulus of experiment is higher than that of calculation (232.5 GPa). The correlation between strength and pressure is confirmed by diffraction peak broadening data. A transition from elastic deformation to plastic deformation of α-Si3N4 at 20 GPa is observed, indicating that α-Si3N4 begins to yield, with yield strength reaching 21 GPa at pressures of up to 20 GPa. A similar phenomenon is observed for MgO, WB3, and c-BC2N. Additionally, theoretical calculations are basically consistent with diffraction experimental results regarding structural stability and mechanical properties.
Uranium-based materials for thermoelectric applications
Authors: Svanidze E. , Veremchuk I. , Leithe-Jasper A. , Grin Yu.
Published: November 2019

Uranium-based compounds possess several properties which make them suitable candidates for thermoelectric applications—complex crystal structures made of heavy components, electrons with enhanced effective masses, as well as low thermal conductivity. However, the difficulty in predicting their properties by computational means, coupled with the lack of experimental investigations on these peculiar systems, limits our understanding of the effect of 5f- and conduction electron hybridization on the Seebeck coefficient, as well as electric and thermal conductivities. In this work, we examine a family of uranium-based materials with a crystal structure of the ternary Zintl phase Y3Au3Sb4. The thermoelectric properties of U3T3Sb4 (T = Ni, Pd, and Pt) compounds are highly dependent upon their microstructures and compositions, arising from the differences in their synthesis. The maximum value of the thermoelectric figure of merit ZT≈0.02 was obtained for the U3Pt3Sb4 compound in the −100 °C ≤T≤ 100 °C temperature range, which makes this material interesting for further development in aerospace applications.
Pollination by nectar-foraging thynnine wasps in the endangered Caladenia arenaria and Caladenia concolor (Orchidaceae)
Authors: Reiter Noushka , Bohman Björn , Freestone Marc , Brown Graham R. , Phillips Ryan D.
Published: November 2019

Prior to undertaking conservation translocations of plants with specialised pollination systems, it is important to ensure the presence of pollinators at recipient sites. Here, for two threatened species, Caladenia concolor Fitzg. and Caladenia arenaria Fitzg. (Orchidaceae), we determine (i) the pollination strategy used, (ii) which floral visitors are involved in pollination, and (iii) whether the pollinator species are present at potential translocation sites. For both orchid species, pollination was primarily achieved by nectar-foraging thynnine wasps, with a single species responsible for pollination in C. concolor, whereas C. arenaria utilised at least two species to achieve pollination. Both orchid species secreted meagre quantities of sucrose on the upper surface of the labellum. Visits to C. concolor occurred primarily in the late afternoon, with some wasps perching on the flowers overnight. Surveys revealed that pollinators were present at all extant populations and most potential translocation sites for both orchids. The specialisation on one pollinator species in C. concolor means that the distribution of the pollinator needs to be considered for conservation translocations. With C. arenaria, the risk of hybridisation with other Caladenia that are known to share one of its pollinator species needs to be taken into account when selecting translocation sites.
Predicting general practitioner utilisation at a small area level across Western Australia
Authors: Lyle Greg , Hendrie Delia
Published: November 2019

Equitable delivery of GP services is a key goal in universal healthcare systems. In Australia, information to evaluate equitable delivery is limited, especially at finer geographic scales, leaving an information void that needs to be filled to inform, prioritise and target interventions. To fill this void, GP utilisation was estimated by combining responses on GP utilisation from a national survey differentiated by demographic and area-based socioeconomic and remoteness characteristics with similar characteristics represented geographically at a fine scale. These estimates were then compared to actual GP utilisation to evaluate their predictive reliability. Comparable estimates were found in the greater metropolitan area, with 76% of areas having estimated GP utilisation within ±10% of actual utilisation. Larger discrepancies were found as areas became remoter, with 84% of areas reporting estimated utilisation that was higher than actual utilisation. Comparing the geographic differences between estimated and actual utilisation allowed us to examine the reliability of our methodology. Given the identified limitations, a proxy for GP utilisation at a small area level can be created, a dataset that is not currently published at this geography. This approach has the potential to be applied Australia-wide, providing another valuable tool to evaluate the equitable delivery of primary health care nationally.
Analytical Beamlet Code 3D for neutral beam injectors: principles and applications
Authors: Harder N den , Rittich D , Orozco G , Hopf C
Published: November 2019

Neutral beam injection is the main heating system on a variety of fusion devices, and will be the main heating system of ITER. Especially during high-power operation in long pulse devices, it is important that transmission losses and power deposition in the beamline are well quantified. This paper presents the analytical beamlet code (ABC)3D. ABC3D is based on analytical Gaussian beamlets, and includes shadowing effects. The code is able to calculate emission spectra in the beamline, duct transmission losses, and neutral beam power loads on 3D components. Examples of its application are shown that highlight key results in beam emission spectroscopy, beamline design, and geometry verification in experiments. Limitations to the computational approach are discussed on the basis of a comparison with more advanced calculations.
Micro-crack detection of nonlinear Lamb wave propagation in three-dimensional plates with mixed-frequency excitationyg*
Authors: Zhu Wei-Guang , Li Yi-Feng , Guan Li-Qiang , Wan Xi-Li , Yu Hui-Yang , Liu Xiao-Zhou
Published: November 2019

We propose a nonlinear ultrasonic technique by using the mixed-frequency signals excited Lamb waves to conduct micro-crack detection in thin plate structures. Simulation models of three-dimensional (3D) aluminum plates and composite laminates are established by ABAQUS software, where the aluminum plate contains buried crack and composite laminates comprises cohesive element whose thickness is zero to simulate delamination damage. The interactions between the S0 mode Lamb wave and the buried micro-cracks of various dimensions are simulated by using the finite element method. Fourier frequency spectrum analysis is applied to the received time domain signal and fundamental frequency amplitudes, and sum and difference frequencies are extracted and simulated. Simulation results indicate that nonlinear Lamb waves have different sensitivities to various crack sizes. There is a positive correlation among crack length, height, and sum and difference frequency amplitudes for an aluminum plate, with both amplitudes decreasing as crack thickness increased, i.e., nonlinear effect weakens as the micro-crack becomes thicker. The amplitudes of sum and difference frequency are positively correlated with the length and width of the zero-thickness cohesive element in the composite laminates. Furthermore, amplitude ratio change is investigated and it can be used as an effective tool to detect inner defects in thin 3D plates.
A new technology for controlling in-situ oxygen fugacity in diamond anvil cells and measuring electrical conductivity of anhydrous olivine at high pressures and temperatures*
Authors: Shen Wen-Shu , Wu Lei , Ou Tian-Ji , Yue Dong-Hui , Ji Ting-Ting , Han Yong-Hao , Xu Wen-Liang , Gao Chun-Xiao
Published: November 2019

We present a novel technique for controlling oxygen fugacity, which is broadly used to in-situ measure the electrical conductivities in minerals and rocks during diamond anvil cell experiments. The electrical conductivities of olivine are determined under controlled oxygen fugacity conditions (Mo–MoO2) at pressures up to 4.0 GPa and temperatures up to 873 K. The advantages of this new technique enable the measuring of the activation enthalpy, activation energy, and activation bulk volume in the Arrhenius relationship. This provides an improved understanding of the mechanism of conduction in olivine. Electrical conduction in olivine is best explained by small polaron movement, given the oxygen fugacity-dependent variations in conductivity.
Major impact of queue-rule choice on the performance of dynamic networks with limited buffer size*
Authors: Ling Xiang , Wang Xiao-Kun , Chen Jun-Jie , Liu Dong , Zhu Kong-Jin , Guo Ning
Published: November 2019

We investigate the similarities and differences among three queue rules, the first-in-first-out (FIFO) rule, last-in-first-out (LIFO) rule and random-in-random-out (RIRO) rule, on dynamical networks with limited buffer size. In our network model, nodes move at each time step. Packets are transmitted by an adaptive routing strategy, combining Euclidean distance and node load by a tunable parameter. Because of this routing strategy, at the initial stage of increasing buffer size, the network density will increase, and the packet loss rate will decrease. Packet loss and traffic congestion occur by these three rules, but nodes keep unblocked and lose no packet in a larger buffer size range on the RIRO rule networks. If packets are lost and traffic congestion occurs, different dynamic characteristics are shown by these three queue rules. Moreover, a phenomenon similar to Braess’ paradox is also found by the LIFO rule and the RIRO rule.
Study of highly excited vibrational dynamics of HCP integrable system with dynamic potential methods*
Authors: Wang Aixing , Sun Lifeng , Fang Chao , Liu Yibao
Published: November 2019

Highly excited vibrational dynamics of phosphaethyne (HCP) integrable system are investigated based on its dynamic potentials. Taking into consideration the 2:1 Fermi resonance between H–C–P bending vibrational mode and C–P stretching vibrational mode, it is found that the effects of H–C stretching vibrational mode on vibrational dynamic features of the HCP integrable system are significant and regularly vary with Polyad numbers (P number). The geometrical profiles of the dynamic potentials and the corresponding fixed points are sensitive to the variation of H–C stretching vibrational strength when P numbers are small, but are not sensitive when P numbers become larger and the corresponding threshold values become lower. The phase space trajectories of different energy levels in a designated dynamic potential (P = 28) were studied and the results indicated that the dynamic potentials govern the various dynamic environments in which the vibrational states lie. Furthermore, action integrals of the energy levels contained in dynamic potential (P = 28) were quantitatively analyzed and elucidated. It was determined that the dynamic environments could be identified by the numerical values of the action integrals of trajectories of phase space, which is equivalent with dynamic potentials.
Highly sensitive detection of Rydberg atoms with fluorescence loss spectrum in cold atoms*
Authors: Shi Xuerong , Zhang Hao , Jing Mingyong , Zhang Linjie , Xiao Liantuan , Jia Suotang
Published: November 2019

Fluorescence loss spectrum for detecting cold Rydberg atoms with high sensitivity has been obtained based on lock-in detection of fluorescence of 6P3/2 state when cooling lasers of the magneto-optical trap are modulated. The experiment results show that the signal to noise ratio has been improved by 32.64 dB when the modulation depth (converted to laser frequency) and frequency are optimized to 4 MHz and 6 kHz, respectively. This technique enables us to perform a highly sensitive non-destructive detection of Rydberg atoms.
Influences of grain size and microstructure on optical properties of microcrystalline diamond films*
Authors: Wang Jia-Le , Chen Cheng-Ke , Li Xiao , Jiang Mei-Yan , Hu Xiao-Jun
Published: November 2019

Microcrystalline diamond (MCD) films with different grain sizes ranging from 160 nm to 2200 nm are prepared by using a hot filament chemical vapor deposition (HFCVD) system, and the influences of grain size and structural features on optical properties are investigated. The results show that the film with grain size in a range of 160 nm–310 nm exhibits a higher refractive index in a range of (2.77–2.92). With grain size increasing to 620±300 nm, the refractive index shows a value between 2.39 and 2.47, approaching to that of natural diamond (2.37–2.55), and a lower extinction coefficient value between 0.08 and 0.77. When the grain size increases to 2200 nm, the value of refractive index increases to a value between 2.66 and 2.81, and the extinction coefficient increases to a value in a range of 0.22–1.28. Visible Raman spectroscopy measurements show that all samples have distinct diamond peaks located in a range of 1331 cm−1–1333 cm−1, the content of diamond phase increases gradually as grain size increases, and the amount of trans-polyacetylene (TPA) content decreases. Meanwhile, the sp2 carbon clusters content and its full-width-at-half-maximum (FWHM) value are significantly reduced in MCD film with a grain size of 620 nm, which is beneficial to the improvement of the optical properties of the films.
Beryllium carbide as diffusion barrier against Cu: First-principles study*
Authors: Cao Hua-Liang , Cheng Xin-Lu , Zhang Hong
Published: November 2019

Beryllium carbide is used in inertial confinement fusion (ICF) capsule ablation material due to its low atomic number, low opacity, and high melting point properties. We used the method of climbing image nudged elastic band (CINEB) to calculate the diffusion barrier of copper atom in the crystal of beryllium and beryllium carbide. The diffusion barrier of copper atom in crystal beryllium is only 0.79 eV, and the barrier in beryllium carbide is larger than 2.85 eV. The three structures of beryllium carbide: anti-fluorite Be2C, Be2C-I, and Be2C-III have a good blocking effect to the diffusion of copper atom. Among them, the Be2C-III structure has the highest diffusion barrier of 6.09 eV. Our research can provide useful help for studying Cu diffusion barrier materials.
Thermal-hydrodynamic design of energy-efficient surfaces with inclined oval-trench vortex generators
Authors: Isaev S A
Published: November 2019

In the present study it is found that enhancement of air turbulent flow and heat transfer at Re=104 is influenced by a set of one-row oval-trench dimples of depth 0.25 inclined at an angle of 65° to the incoming flow and located at the heated wall of the rectangular (9×1) narrow channel when the dimple step H is varied. The periodic section of the dimpled channel 8 in length is considered. The dimple step H is varied from 8 to 2. Abnormal enhancement of flow and heat transfer at H=2 is followed by both a 4-fold decrease in relative negative friction and a 6.5-fold increase in relative heat transfer in the separated flow zone. The phenomenon of turbulent flow acceleration with a 1.39-fold increase in the maximum flow velocity (at H=2) in the dimpled narrow channel in comparison to the plane-parallel channel is discovered.
Numerical analysis of the leaflet elasticity effect on the flow in the model of a venous valve
Authors: Gataulin Y A , Yukhnev A D , Smirnov S I , Rosukhovskiy D A
Published: November 2019

The paper presents the results of the numerical study of the flow in a symmetric model of the venous valve with different leaflet elasticity. The focus is on the analysis of the velocity field and the stagnant region. The stagnant region behind the valve is of great practical interest for phlebologists in terms of the potential for the formation of blood clots. The constructed simplified model of the venous valve has given a good qualitative agreement with the clinical ultrasound data on the position of the valve leaflet and the stagnant zone behind the valve.
The flow regimes of the annular swirling turbulent jet
Authors: Ryzhenkov V O , Abdurakipov S S , Mullyadzhanov R I
Published: November 2019

We perform Large-eddy simulations (LES) of an annular swirling turbulent jet. The swirl parameter is considered within the range S = 0.3−0.6. The Reynolds number based on the bulk velocity and outer pipe diameter is 8900 while the outer to inner diameter ratio is 2. We obtain different flow regimes without and with the vortex breakdown occurring for S = 0.4. Coherent vortical structures for each regime are indentified using the azimuthal Fourier decomposition and the Proper orthogonal decomposition (POD). The turbulent kinetic energy accumulates in the first POD modes with the azimuthal number m = 1.
Numerical simulation of heat and moisture transfer in co-current membrane heat exchangers
Authors: Naumkin V S , Nizovtsev M I
Published: November 2019

The paper presents the mathematical model, based on the narrow-channel approximation, for calculating the processes of heat and moisture transfer in membrane heat exchangers and taking into account possible condensation on heat exchange surfaces. The possibility of humidifying the supply air with moisture from the exhaust air in the cold period is considered. It is shown that the membrane co-current heat exchangers can operate without freezing up to the outdoor temperature equal to -20 °C.
Numerical simulation of the electrovortex flow in the non-inductive approximation under the influence of an external magnetic field
Authors: Vinogradov D A , Teplyakov I O , Ivochkin Yu P
Published: November 2019

The results of a numerical study of the structure of an electro-vortex flow under an external magnetic field are presented. It was shown that an external magnetic field can lead to both an increase and a decrease in the intensity of the flux. At the same time, it is necessary to control the external magnetic field in direct current arc furnaces very carefully, since the non-optimal external magnetic field leads to the suppression of the flow in the melting bath.
Influence of controlled pulsations of a liquid flow on the surface temperature of heater with a high heat flux
Authors: Eloyan K S , Kreta A S
Published: November 2019

The removal of high heat fluxes from 100 W/cm2 to 1000 W/cm2 for microelectronics components is one of the difficult tasks in the field of applied thermal physics. One of the important parameters in the task of cooling the intensely heated surfaces of the elements of microelectronics is the surface temperature depending on the operation time. This work is an experimental study of the influence of controlled pulsations of a liquid flow in a two-phase system on the temperature of the heater surface depending on the heat flux. It is shown that for a heat flux of more than 80% of the critical heat flux, the temperature change on the surface of the heater can reach up to 15 °C, which can adversely affect the operation of the cooled chip. In the case of less than 80% of the critical heat flux, the temperature change is less than 4 °C, allowing the cooled chip to work in a stable mode. It is shown that in the case of controlled pulsations of the liquid flow, subregimes are formed with different duration of existence.
Study of Rain Simulation for Aircraft Engine Certification
Authors: Guryanov A I , Evdokimov O A , Veretennikov S V , Guryanova M M , Kalinina K L
Published: November 2019

Engine tests under flight conditions are extremely important at the stage of its complex debugging. These conditions include the simulation of icing, check for the penetration of birds in the inlet vanes, modeling hail and rain. Simulation of rain due to its significant unsteadiness need providing requirements for the concentration of water in the air, the distribution spectrum of droplets by size, the value of the average diameter of the droplets, the mass flow rate curves for the injectors and the conditions of interaction of droplets with air. This paper contains information about the developed method of calculating the characteristics of the injector for the necessary modes of water injection into the engine as well as experimental study of the injector and conducted studies of the parameters of its operation process, including the choice of optimal modes. As a result of the research, an injector was developed that allows to obtain the average median diameter of 2.66 mm and droplets of the certification spectrum. Also there was worked out the schematic diagram of the collector module of the installation for rain simulation that meets the certification requirements: simulation of rain in the “idle power” and “take-off” modes with the condition of simultaneous provision of water concentration in the air of 20 g/m3 and the average median diameter of 2.66 mm. This installation provides operation in transient modes with the condition of maintaining the water concentration in the air of 20 g/m3.
Investigation of the self-similarity of wind velocity and temperature profiles in laboratory modelling of the exchange processes in the atmosphere boundary layer
Authors: Troitskaya Y I , Sergeev D A , Vdovin M I
Published: November 2019

The paper is concerned with investigation of the self-similarity of wind velocity and temperature profiles in a stably stratified temperature turbulent boundary layer over the waved water surface.
Unsteady model of wall-adjacent boiling subcooled liquid flow
Authors: Levin A A , Chudnovsky V M
Published: November 2019

We discuss an approach to constructing a mathematical model of formation and dynamics of the vapor phase on the heat-releasing surface under conditions of unsteady heat flux. We focus on nucleate boiling, since its predictive model is at present most difficult to design. The nucleate boiling stage is described in the form of a homogeneous model that accounts for the heat fluxes associated with the vapor phase presence. The stage of film boiling takes into account the dynamics of a pulsating vapor layer and its heat exchange with subcooled liquid and the heat-releasing surface.
Determination of the vapor film thickness at steady superfluid helium film boiling
Authors: Puzina Yu Yu , Kryukov A P , Yachevsky I A
Published: November 2019

Heat mass transfer processes at superfluid helium boiling is considered for different conditions. Mathematical description is formulated with taking into account the peculiarities of superfluid helium. System of equations is based on the methods of continuum mechanics and molecular kinetic theory. Pressure distribution in the liquid is determined by the hydrostatic difference. At the vapor-liquid interface the Laplace formula is used. The vapor pressure in the film is determined by the non-equilibrium effects in the vapor near the interface. Heat transfer in a liquid is described by the Gorter-Mellink semi-empirical theory. Experimental data on the stationary boiling of superfluid helium under various conditions are interpreted based on the formulated mathematical model. For all cases in the considered range of parameters, the qualitative and in some cases quantitative agreement between the calculated and experimental values of the vapor film thickness were obtained.
Simulation of structure and thermodynamic properties of the double of ozone and carbon dioxide hydrates using molecular and lattice dynamics methods
Authors: Bozhko Yu Yu , Gets K V , Subbotin O S , Belosludov V R
Published: November 2019

Ozone is a very effective medical, industrial and agricultural disinfector, bleacher and deodorizer. Ozone acts very quickly, but its decay rate is also high. Gas hydrate formation is a promising method for storing ozone and ozone-containing gas mixtures. We use molecular dynamics (conjugate gradient) and lattice dynamics method to calculate the free energy double O3+CO2 hydrate of cubic structure I at 270 K and 275 K temperatures and various gas phase compositions. It allowed determining the chemical potential of water molecules depending on pressure at given temperatures and compositions. Comparison with Ih ice and liquid water allowed us to determine regions of O3+CO2 double hydrate stability. The presented results may be useful in studies of thermodynamic stability areas of hydrates obtained from pure ozone (e.g. liquid ozone), its mixtures and in the development of corresponding storage technologies.
Combustion of aluminum and boron powders suspended in the air
Authors: Moiseeva K M , Yu Krainov A
Published: November 2019

This paper presents results on the numerical solution of the flame propagation problem in the air with suspended aluminum and boron particles. The aim of the study is to determine the combustion rate of the Al-B-air mixture depending on the particle mass concentration and its size. The physical and mathematical model of the process is based on the approaches of the mechanics of two-phase reactive media. The numerical method for solving the problem is based on the decay algorithm of an arbitrary discontinuity. It is shown that the apparent burning rate of the aerosol suspension of the mixture of aluminum and boron powders slightly decreases with an increase in the mass fraction of the powder in the mixture.
On a compact finite-difference scheme of the third order of weak approximation
Authors: Ostapenko V V , Polunina E I , Khandeeva N A
Published: November 2019

The stability and accuracy of compact difference schemes with artificial viscosities of the fourth divergence order are studied. These schemes have a third order both of classical approximation on smooth solutions and weak approximation on discontinuous solutions. As a result of the stability analysis of these schemes in the linear approximation, the optimal values of their viscosity coefficients were obtained. Test calculations are presented to demonstrate the advantages of the new compact scheme compared to the TVD and WENO schemes when calculating discontinuous solutions with shock waves.
Influence of surface currents on the nutrient fluxes from the shelf to the deep part of the Black Sea
Authors: Dorofeyev V L , Sukhikh L I
Published: November 2019

Functioning of marine ecosystems strongly depends on nutrient supply. One of the key sources of nutrients in the Black sea is rivers runoff, concentrated mainly on the northwestern shelf (NWS). Due to surface currents waters from NWS propagate into deep part of the basin and transport nutrients into interior basin. Study of this exchange of water mass and nutrients between the NWS and the deep part of the Black Sea is a goal of this work. It is based on the results of numerical modelling evolution of physical and biogeochemical fields of the Black Sea. The interdisciplinary model of the Black Sea ecosystem consists of a circulation model and a biogeochemical one, describing the interactions between different components of the marine ecosystem. It is shown, that nutrient fluxes between NWS and deep sea are defined by intensity and character of surface currents, which depend on regional wind stress vorticity.
Computational and experimental research of a steam turbine system for an intra-cycle compression of fuel
Authors: Borisov Yu A , Pugachuk A S , Sinkevich M V , Khalife H
Published: November 2019

The paper deals with the design of highly efficient small-size turbines. A method for designing a steam gas turbine using numerical methods for calculating the working processes in the flow section is described. The results of the calculated and theoretical research, which allowed determining the main characteristics of the turbine, are given. The estimated efficiency of the resulting turbine was not less than 85%. The results of tests in the model conditions of the model turbine, manufactured using additive technology, are presented. A comparison of experimental and calculated data has led to the conclusion about the adequacy of the developed mathematical model used in the calculated and theoretical research.
Calibration error minimization method of three-dimensional geometry optical meter with two photodetectors
Authors: Ovchinnikov N N , Dvoynishnikov S V , Glavny V G , Yu Sadbakov O , Shepihin I V
Published: November 2019

The paper presents a method for minimizing the calibration error of a triangulation three-dimensional geometry meter with two photodetectors, ensuring a reduction in the calibration error using the method of an arbitrarily oriented flat calibration object in the measuring volume. The method is based on minimizing the deviation from flatness of the result of the reconstruction of a three-dimensional image of a calibration object and can be used in the algorithm for automatic calibration of a triangulation meter of three-dimensional geometry with two photo-receivers.