bluuebunny/crossref_metadata_2025 huggingface dataset:
Importance of the ultrasound-guided approach for the quadratus lumborum muscle and adjacent structures
Authors: A. Aneiros Zapata , MA Mendoza Rebordinos , A. Benito Domingo
Published: December 2019

Introduction Ultrasound is currently a powerful and valuable tool for assessment purposes and for the performance of invasive procedures during physical therapy treatments, to the extent that this technology is becoming essential for many of these techniques. The evolution undergone by ultrasound-guided techniques in our profession derives in the need to research the importance of the combined use of these two powerful tools.

Aims To demonstrate the importance of ultrasound guidance for the treatment of the quadratus lumborum muscle and adjacent structures.

Material and Methods 20 volunteer subjects were evaluated (seven women and 13 men) aged 22 to 54 years who were asymptomatic. Four freehand approaches were performed (two freehand approaches, one approach on acupuncture point V52 and one approach described by Travell and Simons) and two ultrasound-guided approaches (in prone and in side lying). Each approach was performed twice by the same physical therapist. The freehand approaches were performed by two physical therapists with over five years' experience in invasive physical therapy techniques. The assessment and post-intervention measurements were performed by another physical therapist with over five years' experience in ultrasound assessment and invasive physical therapy techniques. Ultrasound-guided approaches were performed by a physical therapist with over five years' experience in invasive techniques and ultrasound assessment. The data were analyzed with SPSS statistical software for Windows.

Results Statistically significant differences were found between the freehand approaches and ultrasound guided approaches regarding the ability to reach the objective/target tissue (17.5% hit ratios compared to 100%), obtaining a mean distance in the failed attempts of 0.5165cm (0.11-1.61cm). In 70% of the freehand approaches the needle was found in the iliocostal muscle. Overall, during the freehand approaches, and without considering the learning effect, the percentages of hits on the target decreased (from 17.5% to 11.25%) and the percentage needle placements on the iliocostal increased (from 70% to 75%).

Conclusions During physical therapy procedures of the quadratus lumborum muscle and peripheral structures ultrasound-guided approaches are essential to reach the target tissue effectively and with safety.
Ultrasound-Guided percutaneous neuromodulation in non-radiating low back pain
Authors: F. Sanmartin Enriquez , F. Valera Garrido , D. Álvarez Prats , O. Carvajal Fernández
Published: December 2019

Background Low back pain is very common, affecting 15–20% of the population each year, and representing of the main causes of physical therapy consultations. Multiple treatments have been defined for chronic low back pain, however, the findings are still controversial, and therefore new and improved solutions are necessary for the population who suffers from low back pain.

Aims To evaluate the effectiveness of ultrasound-guided percutaneous neuromodulation (US-guided PNM) in patients with non-radiating low back pain.

Material and Methods An experimental study was performed in patients with non-radiating low back pain, between the months of march and may of 2018 at the F&S-Narón Physical Therapy clinic, in A Coruña. Functionality was evaluated via the Oswestry questionnaire and pain was evaluated using the visual analog scale (VAS). US-guided NMP was applied to stimulate the medial branch of a L2 posterior ramus and the iliohypogastric and ilioinguinal nerves, following the protocol described by Valera & Minaya, which consists of the application of a PES type current at 10Hz and 240 microseconds, during 15 seconds and for 6 applications. In total, 3 sessions were applied (sequence 1:7:7), once a week after the first week of initiating treatment.

Results Initially, 12 patients participated in the study, aged between 32 and 59 years. The mean age was 41.4 years. Two of the patients abandoned the study due to personal reasons, unrelated to the research. The final sample consisted of 10 subjects, 50% of each sex. 80% of patients improved after the application of the treatment protocol. An important decrease in activity limitations was observed, from 14 to 4.35 points out of 100 according to the Oswestry questionnaire, and a decrease of 6.8 to 2.15 points out of 10 was observed on the VAS scale, which was statistically significant according to the Wilcoxon test (p < 0,05).

Conclusions The ultrasound-guided percutaneous neuromodulation technique used was effective, obtaining positive results in relation to pain and functionality. Clinical studies are necessary with a greater sample size to confirm these findings.
Optimization of switch diagnostics on the MAIZE linear transformer driver
Authors: Shah A. P. , Campbell P. C. , Miller S. M. , Woolstrum J. M. , Sporer B. J. , Patel S. G. , Jordan N. M. , Gilgenbach R. M. , McBride R. D.
Published: December 2019

The MAIZE Linear Transformer Driver consists of 40 capacitor-switch-capacitor “bricks” connected in parallel. When these 40 bricks are charged to ±100-kV and then discharged synchronously, the MAIZE facility generates a 1-MA current pulse with a 100-ns rise time into a matched load impedance. Discharging each of the capacitors in a brick is carried out by the breakdown of a spark-gap switch, a process that results in the emission of light. Monitoring this output light with a fiber optic coupled to a photomultiplier tube (PMT) and an oscilloscope channel provides information on switch performance and timing jitter—whether a switch fired early, late, or in phase with the other switches. However, monitoring each switch with a dedicated detector-oscilloscope channel can be problematic for facilities where the number of switches to be monitored (e.g., 40 on MAIZE) greatly exceeds the number of detector-oscilloscope channels available. The technique of using fibers to monitor light emission from switches can be optimized by treating a PMT as a binary digit or bit and using a combinatorial encoding scheme, where each switch is monitored by a unique combination of fiber-PMT-oscilloscope channels simultaneously. By observing the unique combination of fiber-PMT-oscilloscope channels that are turned on, the prefiring or late-firing of a single switch on MAIZE can be identified by as few as six PMT-oscilloscope channels. The number of PMT-oscilloscope channels, N, required to monitor X switches can be calculated by 2N = X + 1, where the number “2” is selected because the PMT-oscilloscope acts as a bit. In this paper, we demonstrate the use of this diagnostic technique on MAIZE. We also present an analysis of how this technique could be scaled to monitor the tens of thousands of switches proposed for various next generation pulsed power facilities.
On the alloying and strain effects of divacancy energy level in n-type Si1 − xGex
Authors: Mamor Mohammed , Bouziane Khalid , Maaza Malik
Published: December 2019

Deep level transient spectroscopy was used to investigate point defects introduced by room temperature He-ion irradiation in both fully strained and partially relaxed phosphorous doped n-type Si1 − xGex films epitaxially grown on the Si (001) substrate by chemical vapor deposition. Two major point defects are identified as the doubly negative charge state of the divacancy (V2=/−) and the V-P pair (E-center). The activation enthalpy (EH) of V2=/− was investigated upon strain and alloying effects in order to quantify their individual impact. The deduced variation of activation enthalpy associated with the sole strain effect in strained films is found to decrease linearly as a function of strain (tetragonal mismatch), corresponding to 56 meV/GPa regardless of the degree of strain relaxation for 0 ≤ × ≤ 0.1. This result may suggest that while the strain and alloying have an additive effect on the variation of EH, may however have different physical origins.
Hybrid meta-structure for broadband waterborne sound absorption
Authors: Yang Haibin , Zhao Honggang , Yin Jianfei , Wen Jihong
Published: December 2019

A new hybrid-mechanism metastructure combined resonances of locally resonant scatterers and air cavities is proposed for broadband waterborne sound absorption. In the design, the locally resonant scatterers are embedded into the backing plate of a rubber layer with air cavities. The results demonstrate significant absorption improvement in the low-frequency range using the locally resonant scatterers. Cavities of mixed sizes and locally resonant scatterers of mixed types can be used to achieve efficient absorption over an ultrawide band. This broadband absorption is found to be attributed to the hybrid-mechanism of the resonances of the cavities and the locally resonant scatterers. Furthermore, the absorption mechanism is illustrated by the displacement patterns, the absorption contribution decomposition analysis, and the effective medium theory.
Tuning high-Q superconducting resonators by magnetic field reorientation
Authors: Zollitsch Christoph W. , O’Sullivan James , Kennedy Oscar , Dold Gavin , Morton John J. L.
Published: December 2019

Superconducting resonators interfaced with paramagnetic spin ensembles are used to increase the sensitivity of electron spin resonance experiments and are key elements of microwave quantum memories. Certain spin systems that are promising for such quantum memories possess “sweet spots” at particular combinations of magnetic fields and frequencies, where spin coherence times or linewidths become particularly favorable. In order to be able to couple high-Q superconducting resonators to such specific spin transitions, it is necessary to be able to tune the resonator frequency under a constant magnetic field amplitude. Here, we demonstrate a high-quality, magnetic field resilient superconducting resonator, using a 3D vector magnet to continuously tune its resonance frequency by adjusting the orientation of the magnetic field. The resonator maintains a quality factor of >105 up to magnetic fields of 2.6 T, applied predominantly in the plane of the superconductor. We achieve a continuous tuning of up to 30 MHz by rotating the magnetic field vector, introducing a component of 5 mT perpendicular to the superconductor.
The effects of annealing temperature and heating rate on Ta/TbFeCo bilayers
Authors: Ye Lin-Xiu , Bhatt Ramesh C. , Lee Ching-Ming , Chang Shih-Min , Wu Te-ho
Published: December 2019

Among various perpendicularly anisotropic magnetic materials, amorphous rare earth-transition metal RE-TM alloys have attracted much interest due to the advantages of tunable magnetic properties and suitable perpendicular magnetic anisotropy (PMA) strength. In this study, the magnetic properties of the Ta/TbFeCo/MgO structure with various Tb-contents are investigated under different annealing conditions like heating rate and annealing temperature. The samples were annealed at heating rate from 10 °C/min to 50 °C/min and holding time was varied from 10 min to 30 min with annealing temperatures ranging from 100 to 150 °C. We found that fast heating rate and low holding temperature help to improve PMA and significantly increase the saturation magnetization and squareness of the TbFeCo films.
Solute release from an elastic capsule flowing through a microfluidic channel constriction
Authors: Luo Zheng Yuan , Bai Bo Feng
Published: December 2019

In recent years, microfluidic channels with narrow constrictions are extensively proposed as a new but excellent possibility for advanced delivery technologies based on either natural or artificial capsules. To better design and optimize these technologies, it is essential and helpful to fully understand the releasing behavior of the encapsulated solute from capsules under various flow conditions which, however, remains an unsolved fundamental problem due to its complexity. To facilitate studies in this area, we develop a numerical methodology for the simulation of solute release from an elastic capsule flowing through a microfluidic channel constriction, in which the tension-dependent permeability of the membrane is appropriately modeled. Using this model, we find that the release of the encapsulated solute during the capsule’s passage through the constriction is enhanced with the increase in the capillary number and constriction length or the decrease in the constriction width. On the other hand, a large variation in the channel height, which is generally larger than the capsule diameter, generates little effect on the released amount of the solute. We reveal that the effects of the capillary number and constriction geometry on the solute release are generally attributed to their influence on the capsule deformation. Our numerical results provide a reasonable explanation for previous experimental observations on the effects of constriction geometry and flow rate on the delivery efficiency of cell-squeezing delivery systems. Therefore, we believe these new insights and our numerical methodology could be useful for the design and optimization of microfluidic devices for capsule-squeezing delivery technologies.
The legacy of pasture improvement causes recruitment failure in grassy eucalypt woodland conservation reserves in the Midlands of Tasmania
Authors: Romanin Louise M. , Prior Lynda D. , Bowman David J. M. S.
Published: December 2019

Australia’s most fragmented and least reserved landscapes are the grassy eucalypt woodlands of the south-east. Two hundred years of agricultural disruption have transformed these landscapes, and agricultural enterprises continue to expand and develop, meaning the threats to these landscapes have not abated. The Tasmanian Midlands is primarily privately owned, with very little area devoted to conservation of biodiversity. In this landscape, conservation covenants have been enacted on many private properties with the intention of encouraging tree recruitment and conservation of threatened plant communities and rare species. Evidence of the effectiveness of these covenants in protecting overstorey tree population health is lacking. This study compared the demographic structures of overstorey Eucalyptus species and midstorey tree genera on public and private properties with contrasting land use histories. Reserves on private lands had little tree recruitment, probably because exotic pasture species were common, whereas tree recruitment was abundant in public reserves, where pasture improvement has not occurred. Active measures are needed to restore ecological structure and function in grassy woodland conservation reserves on private land by encouraging regeneration of Eucalyptus and Acacia species as well as returning the ground layer to a functionally native state. This will entail reinstating fire disturbance, reducing exotic pasture species cover and managing domesticated, feral and native herbivores.
Gender Differences in Association of Prescription Opioid Use and Mortality: A Propensity-Matched Analysis from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Prospective Cohort
Authors: Khodneva Yulia , Richman Joshua , Kertesz Stefan , Safford Monika M.
Published: December 2019

Background

Prescription opioids (PO) have been widely used for chronic non-cancer pain, with commensurate concerns for overdose. The long-term effect of these medications on non-overdose mortality in the general population remains poorly understood. This study's objective was to examine the association of prescription opioid use and mortality in a large cohort, accounting for gender differences and concurrent benzodiazepine use, and using propensity score matching.

Methods

29,025 US community-dwellers were enrolled in the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort between 2003 and 2007, and followed through December 31, 2012. At baseline there were 1907 participants with PO; 1864 of them were matched to participants without PO, based on the model-derived propensity to receive opioid prescriptions. Causes of death were expert-adjudicated.

Results

Over median follow-up of 6 years there were 4428 deaths (413 among persons with PO). The risk for all-cause mortality was 12% higher, in absolute terms, for persons with PO compared to those without PO in the overall sample, with gender differences (interaction p = .0008). The risk of death was increased for women with PO (hazard ratio [HR] 1.21 [95% Confidence Interval (CI) 1.04–1.40]), but not men (HR 0.92 [95% CI 0.77–1.10]). Women with PO were at higher risk of cardiovascular disease (CVD) death (HR 1.43 [95% CI 1.12–1.84]), sudden death (HR 2.02 [95% CI 1.29–3.15]) (a subset of CVD death), and accidents (HR 2.18 [95% CI 1.03–4.60]). These risks were not observed for men with PO.

Conclusion

Over 6 years of follow-up, women but not men who had opioid prescriptions were at higher risk of all-cause mortality, CVD death, sudden death, and accidents. Special caution in prescribing opioids for women may be warranted until these findings are confirmed.
In vitro thermal adaptation of mesophilic Acetobacter pasteurianus NBRC 3283 generates thermotolerant strains with evolutionary trade-offs
Authors: Matsumoto Nami , Matsutani Minenosuke , Azuma Yoshinao , Kataoka Naoya , Yakushi Toshiharu , Matsushita Kazunobu
Published: December 2019

Thermotolerant strains are critical for low-cost high temperature fermentation. In this study, we carried out the thermal adaptation of A. pasteurianus IFO 3283–32 under acetic acid fermentation conditions using an experimental evolution approach from 37ºC to 40ºC. The adapted strain exhibited an increased growth and acetic acid fermentation ability at high temperatures, however, with the trade-off response of the opposite phenotype at low temperatures. Genome analysis followed by PCR sequencing showed that the most adapted strain had 11 mutations, a single 64-kb large deletion, and a single plasmid loss. Comparative phenotypic analysis showed that at least the large deletion (containing many ribosomal RNAs and tRNAs genes) and a mutation of DNA polymerase (one of the 11 mutations) critically contributed to this thermotolerance. The relationship between the phenotypic changes and the gene mutations are discussed, comparing with another thermally adapted A. pasteurianus strains obtained previously.
EURAMET-T.K9.1 bilateral comparison of ITS-90 SPRT calibration from the Hg TP to Zn FP
Authors: Olsen Åge Andreas Falnes , Opel Karsten , Tammik Kristjan
Published: December 2019

Justervesenet (JV, Norway) and Metrosert (Estonia) agreed in 2016 to conduct a bilateral comparison of SPRT calibrations for the fixed points from the triple point of Hg to the freezing point of Zn, with the exception of the freezing point of In which Metrosert could not realise. The aim of the comparison was to link Metrosert to the CCT-K9 via the EURAMET-T.K9. JV was the linking laboratory to the EURAMET-T.K9 and the pilot. An SPRT was first calibrated at Metrosert, shipped to JV and calibrated there, and finally returned to Metrosert for a second calibration. The measurements were carried out and completed in 2017.

The results show that the laboratories involved are in agreement. At the triple point of Hg and the melting point of Ga the results are consistent and agree at all three reported measurements. At the freezing points of Sn and Zn Metrosert observes some change in W-values, although the difference is smaller than the reported uncertainty. The difference may suggest some drift either in the circulating probe or in the reference equipment at Metrosert, and this discrepancy increased the uncertainty in the degree of equivalence somewhat.

The resistance of the probe was measured at the triple point of water after every fixed point, and prior to and after annealing upon reception at the laboratories. In general the resistance values are stable, but may suggest some drift between the first measurements at Metrosert and the measurements at JV.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Supplementary comparison EURAMET.AUV.A-S2
Authors: Rodrigues Dominique , Rosenkranz Peter , Barrera-Figueroa Salvador , Guglielmone Claudio , Soares Zemar M Defilippo , Kling Christoph
Published: December 2019

The Supplementary comparison EURAMET.AUV.A-S2 has been carried out under the auspices of the Consultative Committee on Acoustics, Ultrasound and Vibration (CCAUV) of the International Bureau of Weights and Measures (BIPM). This comparison is concerned with secondary free-field methods of microphone calibration, particularly the methods described in the International Standard IEC 61094-8 (2012). The participating NMI's are BEV (Austria), DFM (Denmark), INMETRO (Brazil), INRiM (Italy), LNE (France), NPL (UK) and PTB (Germany). The role of Pilot laboratory was undertaken by LNE (France). The measurements took place between February 2014 and June 2016. Two WS2 microphones were circulated. This report includes the measurement results from the participants, information about their calibration methods, and the analysis leading to the assignation of equivalence degrees.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Four-station laser tracer-based geometric error measurement of rotary table
Authors: Zha Jun , Li Linhui , Han Lin , Chen Yaolong
Published: December 2019

The geometric errors of numerical control (NC) rotary tables can be measured using a single instrument according to the conventional measurement method. This study presents an efficient method for this measurement using four-station laser tracers. A 3D coordinate measurement algorithm of the four-station laser tracer was established, the self-calibration of the laser tracer position and the spatial measuring point algorithm was realized, and the volumetric error of the measuring point on the rotary table was obtained. Then, the geometric errors of the NC rotary table were modeled using the screw theory, and a three-point measurement method was proposed to realize the separation of these geometric errors. Using the geometric error measurement experiment, six geometric errors of the NC rotary table were obtained. Compared with the conventional standard ball and laser interferometer measurement methods, the radial and axial runout results obtained using the laser tracer show differences of 0.08 and 0.07 µm, respectively, and the result of positioning error measurement shows a difference of 2.2 µrad. In addition, the method proposed in this study demonstrates an efficiency improved by five times, under the premise of ensuring the measurement accuracy, which broadens the possibilities for applications of rotation axes’ geometric error measurement in machining centers.
Plasma wakefield accelerator driven coherent spontaneous emission from an energy chirped electron pulse
Authors: Alotaibi B M , Altuijri R , Habib A F , Hala A , Hidding B , Khalil Sh M , McNeil B W J , Traczykowski P
Published: December 2019

Plasma accelerators (Esary et al 2009 Rev. Mod. Phys.
81 1229) are a potentially important source of high energy, low emittance electron beams with high peak currents generated within a relatively short distance. As such, they may have an important application in the driving of coherent light sources such as the Free Electron Laser (FEL) which operate into the x-ray region (McNeil and Thompson 2010 Nat. Photon.
4 814–21). While novel plasma photocathodes (Hidding et al 2012 Phys. Rev. Lett.
108 035001) may offer orders of magnitude improvement to the normalized emittance and brightness of electron beams compared to Radio Frequency-driven accelerators, a substantial challenge is the energy spread and chirp of beams, which can make FEL operation impossible. In this paper it is shown that such an energy-chirped, ultrahigh brightness electron beam, with dynamically evolving current profile due to ballistic bunching at moderate energies, can generate significant coherent radiation output via the process of Coherent Spontaneous Emission (CSE) (Campbell and McNeil 2012 Proc. FEL2012 (Nara, Japan)). While this CSE is seen to cause some FEL-induced electron bunching at the radiation wavelength, the dynamic evolution of the energy chirped pulse dampens out any high-gain FEL interaction. This work may offer the prospect of a future plasma driven FEL operating in the high-gain Self Amplified CSE mode.
100 years of nuclear isomers—then and now
Authors: Walker Philip , Podolyák Zsolt
Published: December 2019

The suggestion that some atomic nuclei would be able to exist in more than one stable or metastable configuration was proposed by Soddy in 1917. Subsequently, the first experimental example of such an isomeric pair was reported by Hahn in 1921, in the form of two metastable states of 234Pa, then known as UZ and UX2. Nowadays, of the 3437 nuclides listed in the most recent NUBASE evaluation, 1318 have at least one metastable excited state with a half-life of 100 ns or longer. The present work reviews historical aspects of nuclear isomers, and the different physical mechanisms that lead to their formation. Selected frontiers of contemporary isomer research are discussed, with an emphasis on remote regions of the nuclear landscape. Some possibilities for the electromagnetic manipulation of isomers are included.
Entropy-SGD: biasing gradient descent into wide valleys*
Authors: Chaudhari Pratik , Choromanska Anna , Soatto Stefano , LeCun Yann , Baldassi Carlo , Borgs Christian , Chayes Jennifer , Sagun Levent , Zecchina Riccardo
Published: December 2019

This paper proposes a new optimization algorithm called Entropy-SGD for training deep neural networks that is motivated by the local geometry of the energy landscape. Local extrema with low generalization error have a large proportion of almost-zero eigenvalues in the Hessian with very few positive or negative eigenvalues. We leverage upon this observation to construct a local-entropy-based objective function that favors well-generalizable solutions lying in large flat regions of the energy landscape, while avoiding poorly-generalizable solutions located in the sharp valleys. Conceptually, our algorithm resembles two nested loops of SGD where we use Langevin dynamics in the inner loop to compute the gradient of the local entropy before each update of the weights. We show that the new objective has a smoother energy landscape and show improved generalization over SGD using uniform stability, under certain assumptions. Our experiments on convolutional and recurrent networks demonstrate that Entropy-SGD compares favorably to state-of-the-art techniques in terms of generalization error and training time.
Operational and physical characteristics of self-drilling rock bolt
Authors: Zubkov A A , Kutlubaev I M , Samigullin V A , Buzmakov V A
Published: December 2019

The key factor in the operation safety for the shaft mining is stabilization of the working surface [1]. The time required to install support element is crucial [2, 3]. Surface stabilization can be done three ways: using frame support or rock bolt or their combination [4]. The rock stabilizing method is realized using significant number of design options of rock stabilizer systems [5, 6]. Friction rock bolts with tubular profile have become widespread recently [7 -9]. Its fixation in borehole is based on generation of friction force at contact surface. There are two methods realized: Swellex and Split Set. According to the first method the closed tubular profile (after being freely inserted into borehole) that has working liquid inside forced under the high pressure is used. Under the pressure outside dimension of profile is increased and its forcing against the borehole surface is provided [10]. The second method is based on use of spindle with unclosed tubular profile and outside diameter that exceeds the spindle diameter [11]. When spindle is inserted into borehole it elastically deforms at cross section. By means of that the distributed pressure is provided on contact surface. This operating principle of spindle and borehole interaction determined name of the support as self-installing rock bolt (SARB). Usage of SARB is preferable for building temporary support because of smaller time expenditure on installation.
Features of chromatographic separation on heteropaternal sorbents
Authors: Bogoslovskii S Y , Ivankin A N , Boldyrev V S
Published: December 2019

The possibility of using a short 20x4 mm chromatographic column with a heterosurface sorbent for direct determination of theophylline and caffeine in blood plasma and a 120x4 mm column for determination of tetracycline antibiotics in cow’s milk was studied. Complete separation of tetracycline peaks was not achieved. Determination of caffeine and theophylline was performed successfully in plasma filtrates without long and time-consuming stages of preliminary preparation of the sample without protein deposition. Before backwashing, unfiltered blood plasma can be injected in an amount equivalent to 50 mg of dry matter. Retention characteristics of caffeine and theophylline are practically stable: the retention factor of theophylline for k = 4,0 + 0,1 for caffeine k = 8,5 + 0,4 eluent in composition of 0.02 M sodium hydrogen phosphate (pH = 6,0) – acetonitrile (90:10).
Low-cycle fatigue life prediction of a variable thickness disk
Authors: Veretimus D K , Veretimus N K
Published: December 2019

The turbomachines are characterized by complex geometry of the main parts and extreme operation conditions. The review of the testing results indicates that in most cases the failure of turbine disks and blades is caused by low- and high-cycle fatigue. We included the experimental dependences of the material properties of temperature, time and number of loading cycles in the fatigue life calculation. This enabled us to observe the kinetics of the part stress-strain state which is present even under constant external load. The observed increase of strain (decrease of stress) at the constant external load indicates the process of cyclic damage accumulation in the disk material. The plastic strains determine the damage fields (distribution of damage in the part material) which in turn allow predicting the area of initiation and probable growth direction of a fatigue crack in a part. We chose a material damage model, and numerically calculated the damage field by taking into account the change of the part stress-strain state with the number of cycles. The damage fields allow determining the point life (time or number of cycles to failure since the moment when a crack passes through a given point), the number of cycles before crack initiation, number of cycles to failure with a crack, crack propagation speed in the damaged and not damaged material. Finally, we determined the permissible number of cycles, time to failure and crack length with a given safety factor. The numerical investigations of the cyclic failure of machine parts should be conducted taking into account the kinetics of the accumulated damage fields.
Synthesis of highly dispersed calcium carbonate at excessive pressure of carbon dioxide
Authors: Bogoslovskii S Yu , Mechandin A G , Boldyrev V S , Kovalenko A S
Published: December 2019

The purpose of the paper was to find out how the conditions for the synthesis of calcium carbonate, having the patent of the Russian Federation No. 2489355, affect the average particle size and their size distribution. The process was carried out in a transparent 1 liter plastic reactor; the excess pressure of carbon monoxide (IV) was quickly created and sharply dropped in no longer than 90 seconds at a temperature of 25ºC and in no longer than 6 minutes at 6ºC. The obtained highly dispersed carbonate was studied microscopically, and a histogram of the particle size distribution was constructed. The optimum process time at room temperature is 60 seconds. The resulting product is characterized by a narrow particle size distribution with a maximum of about 2.5 µm. The particle size reduction occurs when either the reaction time or the temperature decreases. Aggregate stability of the suspension depends on the molar ratios of calcium hydroxide and carbon monoxide (IV). The activation energy of the reaction is 59 kJ / mol.
The electromagnetic field distribution in the 1D layered quasiperiodic dispersive media
Authors: Gorelik Vladimir , Bi Dongxue , Klimova Natalia , Pichkurenko Svetlana , Filatov Vladimir
Published: December 2019

In the paper, we analyze the layer-by-layer electromagnetic field distribution in a quasiperiodic dispersive aluminum photonic crystal film. We propose the new way to calculate such structures without the finite-difference time-domain (FDTD) numerical computing agreed with both the experimental spectrum and the FDTD simulation. Also, we found the first pore electromagnetic pumping at the photonic bandgap edge which is useful for the various fundamental and engineering applications.
A study of hemodynamics and the structure of capillary blood flow using the method of laser speckle contrast analysis LASCA
Authors: Nebritova O A
Published: December 2019

The LASCA method can be applied to the study of microcirculation of superficial microvessels. A chicken embryo of the 5th - 7th day of incubation was used as a model of the vascular system. The effect of laser occlusion of a vessel on blood microcirculation in the vascular system was studied. Using the LASCA method, we can conclude about the presence or absence of the blood flow in the vascular system. The contrast value C, calculated by the method, shows the blood redistribution in the vascular system before and after occlusion.
Development of educational video materials collection as a part of special conditions for hearing impaired students while studying chemistry at technical university
Authors: Gurov A A , Oreshkina O A
Published: December 2019

BMSTU trains hearing impaired persons as engineers on inclusive programs. The subjects of the inclusive educational process are students with hearing impairment of varying severity. The key need of this contingent of students is the content accessibility of educational resources in the disciplines of fundamental engineering, including chemistry. BMSTU solves the problem of accessibility of such disciplines as chemistry for hearing impaired students through creation of special educational conditions during study, taking into account individual characteristics of restricted information perception, restricted life activities and degree of their severity in students. Special conditions form a special accessible multimodal educational environment learning process in chemistry for students with hearing impairments. An element of forming such an environment was the development of a collection of educational multimedia video materials on the chemistry course topics. Involving deaf and hard-of-hearing students themselves in development of demonstration experiments as part of the educational process in chemistry and creation of a complex of video materials are important cognitive and social factors that increase their motivation to study chemistry.
Modern X-ray refraction optics in the course of physics of Technical University
Authors: Smirnov E V
Published: December 2019

The review of modern achievements in X-ray optics taking into account the refraction of X-rays in the matter is given. The complete external reflection of X-ray radiation from the substance allowing creating mirrors for X-ray radiation is considered. Much attention is paid to the practical use of the whispering gallery effect for X-ray radiation. An analysis of the focusing and collimation of X-ray beams by refractive lenses is given. The urgent need to include this material in the course of physics, as well as in courses on X-ray optics at Technical Universities of Russia, is noted.
Relativistic positrons dynamics in the electrostatic field of perfect periodic positively charged structures
Authors: Gorev V V , Strekalov D E
Published: December 2019

In this paper, the channeling effect is considered, which consists in the ability of charged particles to penetrate relatively large distances into the interior of the crystal, in which particles move in the interplanar space and are affected by an electrostatic field created by ions of the crystal lattice. Interest in this effect arises due to the fact that channeling is accompanied by directed electromagnetic radiation. This was facilitated, on the one hand, by the versatility and complexity of the problem from a theoretical point of view and, on the other hand, by the practical possibility of using such radiation, the parameters of which can vary in a wide range by changing the parameters of the crystal structure in many fields of science and technology. In the work, the electrostatic field inside an arbitrary periodic structure is considered and a mathematical model is constructed that describes the main characteristics of the field in the ellipsoidal approximation: the scalar potential of the electric field and its intensity. The paper also provides all the necessary mathematical relationships.
Electromagnetically induced transparency in Ruby
Authors: Alimkina I S , Filatov V V , Gorelik V S
Published: December 2019

In this paper, the authors show new results on the electromagnetically induced transparency in ruby. At the powerful laser excitation, the authors observed the room-temperature Bose-Einstein polaritonic condensation, the ruby optical over-transparency and the traces of hidden photonic states. The results are crucial to the paraphoton lasing.
Nuclear battery based on beta decay of isotopes of radioactive elements
Authors: Fedorov R A , Chudova S A
Published: December 2019

This article is dedicated to the creation of the nuclear battery as a portable source of electric power, capable of producing energy for a long period, and the prospects of using them as energy storage devices for consumer goods. This article will consider existing analogues and ways of improving them.
Cluster radioactivity: analysis, forecast, new factors of slowing the decay of atomic nuclei
Authors: Okunev V S
Published: December 2019

Some regularities of cluster decays are revealed, which make it possible to predict the existence of a large number of medium, heavy and, possibly, superheavy f-active nuclei. The stability of the majority of non-magic nuclides (products of cluster radioactivity) is explained by the simultaneous action of the already known factors slowing (stabilizing) the radioactive decays of atomic nuclei and some additional factors. Among the additional factors, a weakly expressed effect of pairing of α-particles in light nuclei can be noted. In some cases, an additional particle (neutron, proton or light cluster) contributes to the stability of the nucleus by intensifying the forces of mutual nuclear attraction. Compact arrangement of α-clusters in another additional factor stabilizing the nuclei. One more factor is associated with compact placement of neutrons (possibly paired) between α-clusters within the of light nuclei.
On the research of the magnetic field between the plates of a plane capacitor
Authors: Sumnitelnyi N V , Sorokin D L
Published: December 2019

The purpose of the paper was to consider the impact of the displacement current in magnetic field in the vicinity of the plane capacitor plates. We obtained a magnetic field model that accounted for the effects of both displacement currents and conduction currents. Theoretical calculations of the surface on which the magnetic field changes the direction were performed.
RKDG method for 2D gas dynamics simulation on uniform rectangular meshes
Authors: Korchagova Victoria , Fufaev Ivan , Lukin Vladimir , Marchevsky Ilia , Sautkina Sofya
Published: December 2019

This paper is devoted to a numerical simulation of 2D gas dynamics flows on uniform rectangular meshes using the Runge - Kutta - Discontinuous - Galerkin (RKDG) method. The RKDG algorithm was implemented with in-house C++ code based on the experience in the investigation of 1D case. The advantage of the RKDG method over the most popular finite volume method (FVM) is discussed: three basis functions being applied in the framework of the RKDG approach lead to a considerable decrease of the numerical dissipation rate with respect to FVM. The results of the acoustic pulse simulation on a sufficiently coarse mesh with the piecewise-linear approximation show a good agreement with the analytical solution in contrast to the FVM numerical solution. For the Sod problem, the results of the discontinuities propagation illustrate the dependence of the scheme resolution on the numerical fluxes, troubled cell indicator and the limitation technique choice. The possibility to resolve strong shocks is demonstrated with the Sedov cylindrical explosion test.
Assessment of selected parameters of concrete composite containing recyclate obtained from fire-resistant cullet
Authors: Powęzka A , Ogrodnik P , Biedugnis S , Szulej J
Published: December 2019

The purpose of the work is to determine the possibility of using waste from waste heat-resistant cullet as a filler in concrete composites. The article discusses the results of testing selected performance properties of the designed concrete composite. The samples were tested for mechanical properties: compressive strength, impact resistance. Research also included identifying structural changes in the designed composite.
Initial growth state MoS2 thin film by magnetron sputtering
Authors: Belikov A I , Dolomanzhi A , Kalinin V N , Nhan Do Thi , Phyo Kyaw Zin , Syomochkin A I
Published: December 2019

MoS2 thin films were grown on sapphire substrates by the MoS2 target magnetron sputtering, using the DC mode in Ar atmosphere at the substrate temperature of 200 °C for 10, 20 and 30 sec. The results of AFM studies have shown that the morphology of MoS2 thin films changes significantly with the increase of the process time. At the initial stage of growth, after 10 sec of deposition, a continuous film about 3.5 nm thick was observed.
Effect of morphology features of patterned surface on the nucleation processes of In/GaAs nanostructures during droplet epitaxy
Authors: Chernenko N E , Balakirev S V , Eremenko M M , Solodovnik M S
Published: December 2019

We present the results of theoretical studies of the self-organization processes of nanoscale metal In droplets on GaAs(001) substrates with artificial structural heterogeneities of various types – with a rectangular, trapezoidal, and triangular shapes. The study showed that to improve the accuracy of nanostructure positioning and homogeneity, it is necessary to use patterns with triangular grooves. In order to ensure the full groove filling by the material and to suppress the undesirable structure formation outside modified areas, it is necessary to provide sufficient diffusion length of adatoms taking into account the peculiarities of the patterned surface morphology.
The study on agglomerates of WC, TiC, TaC nanopowder mixtures obtained from hard-alloy waste products
Authors: Gavrish V. , Chayka T. , Baranov G.
Published: December 2019

The paper presents findings of the nanopowder obtained from hard-alloy waste (a mixture of tungsten, titanium, and tantalum carbides) under a unique technology. Dispersion, particles’ morphology have been studied. Chemical purity of this nanopowder has been confirmed by X-ray spectral microanalysis.
Study of the mechanical characteristics of the Al2O3 film on the LiNbO3 substrate
Authors: Shumilin A , Shumilina I , Fomin A
Published: December 2019

The microhardness of a thin aluminum oxide film with a thickness of 80 to 240 nm on the surface of a lithium niobate single crystal was determined by the method of nanoindentation. The hardness and Young’s modulus for a film deposited by dc-magnetron sputtering of an aluminum target in a gas (Ar+O2) medium were more than 30 GPa and 300 GPa, respectively. The dependences of the film thickness on the mechanical properties of a layered system, in particular hardness and elastic modulus, were established.
Formation of SiO2 buffer layer for LiNbO3 thin films growth
Authors: Vakulov Z E , Klimin V S , Rezvan A A , Tominov R V , Korzun K , Kots I N , Polyakova V V , Ageev O A
Published: December 2019

This paper shows the results of study of the effect of SiO2 buffer layer thickness on the morphological parameters of nanocrystalline LiNbO3 films formed by pulsed laser deposition. It has been established that with increasing in the thickness of SiO2 buffer layer from 10 nm to 50 nm, the roughness of LiNbO3 films decreases from 5.1 nm to 4.4 nm. The minimum value of the grain diameter (118 nm) corresponds to the thickness of the buffer layer equal to 50 nm. The results obtained can be used in the design and manufacture of integrated acousto-optic and piezoelectric devices, as well as sensitive elements of sensors using various effects of surface acoustic waves.
Study of the ITO sublayer influence on the tubular carbon nanostructures formation
Authors: Il’in O I , Rudyk N N , Kuzhelev M V , Il’ina M V , Fedotov A A
Published: December 2019

The study of the formation of catalytic centers and the growth of CNT-based TCN was carried out on the Ni (10 nm)/ITO (100 nm)/Si (370 μm) structure. Shown that the temperature at the stage of heating and growth has a significant impact on the parameters of the formed TCN. Promising for instrumental use, the TCN were formed at a temperature of 750 °C, a heating time of 20 minutes, an activation time of 3 minutes. The effect of plasma ions at the stages of «activation» and growth was also demonstrated.
Fabrication and luminescent properties of(In,Fe)Sb/GaAs/InGaAs diodes
Authors: Ved M. V. , Dorokhin M.V. , Lesnikov V. P. , Zdoroveyshchev A.V. , Danilov Yu.A. , Demina P.B. , Kudrin A. V.
Published: December 2019

The electrical and luminescent characteristics of InGaAs/GaAs spin light-emitting diodes with an injector based on (In,Fe)Sb were investigated and the circular polarization of the electroluminescence was obtained for such structure. It has been established that the deposition of (In,Fe)Sb layer does not introduce any additional defects into the region of near-surface quantum wells, but directly affects the (In,Fe)Sb/GaAs interface. It was found that the application of a thin protective layer of MgO between the ferromagnetic (In,Fe)Sb injector and the light-emitting structure minimizes this effect.
Simulation of AlGaAs-heterostructures CVC kinetic due to degradation
Authors: Shasurin V D , Vetrova N A , Meshkov S A , Ivanov Y A , Kuimov E V
Published: December 2019

A model of degradation of AlGaAs-heterostructures has been developed. Parasitic resistance growth and diffusion of aluminum and donor impurities are considered as the main reasons of degradation of the structure. Current transfer models are generalized to the case of structures with continuous impurity distribution profiles. Algorithms based on numerical methods with reduced time complexity have been developed. RTS CVC was calculated before and after the annealing operation in order to verify the models. According to the results of the calculation, it was concluded that the developed algorithms are advisable for reliability prediction applications.
Synthesis of glycidoxy spacer on the surface of magnetic nanoparticles and immobilization of albumin
Authors: Korolev D V , Gareev K G , Zorin V N , Evreinova N V , Postnov V N , Romanova T N
Published: December 2019

The glycidine spacer was synthesized from three different solvents. It is shown that the samples synthesized from benzene have the highest efficiency. Human albumin was immobilized onto a glycidine spacer. A mechanism for the interaction of albumin with a glycine spacer is proposed. An analysis of the determination of albumin adsorbed by magnetic nanoparticles was performed in this work.