A Start Trigger Detector for the ALICE Spectrometer

A fall-back option of the T0 start trigger detector was developed for the ALICE setup that was intended for the study of quark–gluon plasma with the LHC accelerator (CERN). The Monte Carlo simulation with the PYTHIA program was performed for a detector incorporating two symmetrical arrays of 12 Cerenkov counters, each composed of 26-mm-diameter Hamamatsu R5505 phototubes with fine-mesh dynodes and a quartz radiator 3 cm in length and 26 mm in diameter. Its simulated detection efficiency for p–p collisions exceeded 88%. A prototype Cerenkov counter, consisting of a R3432-01(similar to R5505) phototube and a quartz radiator with dimensions of 25 × 30 × 12 mm, was tested in a beam of pions and protons with a 1.19-GeV/c-momentum. The time resolution in the 1–200 dynamic range was better than 50 ps.     

Method of determination of truncation parameters from measured surface profile

The probability density function of the roughness height of a sliding surface is not always Gaussian like that of a truncated surface caused by running-in or mild wear. Therefore, it is important for obtaining contact pressure or frictional characteristics to estimate the truncation level of the non-Gaussian distribution function. This paper presents a method of determination of the two truncation parameters in the truncation model presented by King et al. [Proceedings of the 4th Leeds–Lyon Symposium on Tribology, MEP, London, 1978, p. 333]. The two truncation parameters p and β can be determined by plotting the values of skewness S_k and kurtosis K obtained from a measured profile of surface roughness on the S_k–K diagram calculated with the truncation model for various given values of parameters p and β. The height distributions reproduced by the truncation model with the truncation parameters p and β identified by the present method is in good agreement with the original ones of the measured surfaces.     

MAGE Spectrometer for the Investigation of Hadron–Nucleus Interactions and the Identification of Final Nuclear States

A combined spectrometer is composed of a wide-aperture magnetic spectrometer with proportional chambers and a -spectrometer based on a Ge(Li) detector. The respective momentum and the angular resolutions of the magnetic spectrometer are FWHM/p(%) = 0.59p (GeV/c) + 1.1 and 0.5–1 mrad; its average efficiency for 0°–5° angles is 85%. The energy resolution of the -spectrometer is 8 and 16 keV for 0.5- and 2.0-MeV photons, respectively; the average angular acceptance is 1.5 msr.     

An X-ray Backlighting Technique Based on Using X-Pinch Radiation for Probing the Plasma of Multiwire Imploding Liners at the Angara-5-1 Facility

A method for determining the substance density distribution in the plasma produced by a current-driven implosion of multiwire tungsten liners at the Angara-5-1 facility is described. This method is based on the X-ray probing of plasma with radiation from a point source. As a source of this radiation, an X pinch is used. The time resolution (<2 ns) was determined by the X pinch. The probing of both the liner peripheral and near-axial regions is considered. The plasma-attenuated X-pinch radiation was detected using photographic film and p–i–n diodes in the first and second approach, respectively. The spatial resolutions (over the object) in both cases were determined by the sizes of the X pinch and p–i–n diodes and amounted to 4 and 44 m, respectively. The design of the X-pinch and the dependence of its radiation characteristics (the burst time moment and the radiation-pulse power and duration) on the electric and design parameters of the circuit and load are described. The experimental data on the X-pinch radiation spectrum in the range of photon energies of 1–20 keV and the results of studying the substance-density distribution inside liners during the current-driven implosion at the Angara-5-1 facility are presented.     

Identification of yield stress and plastic hardening parameters from a spherical indentation test

Assuming plastic hardening of metals are specified by the stress–strain curve in the form , the material parameters σ₀, k and m are identified from spherical indentation tests by measuring compliance moduli in loading and unloading of the load–penetration curve. The curve P(h_p) is analytically described by a two term expression, each with different exponents. Here, ε_p and h_p denote the plastic strain and permanent penetration. The proposed identification method is illustrated by specific examples including numerical and physical identification tests.     

Efficiency of Pulsed Regimes for Enhancing the Breakdown Strength of Vacuum Insulation

Processing the experimental data on breakdown delay time in a vacuum was used to obtain the function K (t _p) of the relative change in the field gain factor at microscopic inhomogeneities of the cathode surface resulting from the realization of optimum pulse conditioning regimes. It is shown that over the range of pulse durations 10^–8 t _p 10^–6 s, the relative change in the state of the cathode surface corresponds to the relative changes in the breakdown strength of all-metal electrodes and to the voltage of the appearance of local flashes in a system of evaporated electrodes—a microchannel plate and the screen of an image intensifier. Applying optimum regimes for conditioning the surface with pulses of durations t _p < 10^–8 s makes it possible to achieve the limiting breakdown strength determined by the cathode mechanism of breakdown initiation.     

Persistence of Epoxy‐Based Sealer Residues in Dentin Treated With Different Chemical Removal Protocols

The presence of residual endodontic sealer in the pulp chamber may cause discoloration of the dental crown and interfere with the adhesion of restorative materials. The aim of this study was to compare the efficacy of different solvents in removing residues of an epoxy resin‐based sealer (AH Plus) from the dentin walls of the pulp chamber, by scanning electron microscopy (SEM). Forty‐four bovine incisor dental crown fragments were treated with 17% EDTA and 2.5% NaOCl. Specimens received a coating of AH Plus and were left undisturbed for 5 min. Then, specimens were divided in four groups (n = 10) and cleaned with one of the following solutions: isopropyl alcohol, 95% ethanol, acetone solution, or amyl acetate solution. Negative controls (n = 2) did not receive AH Plus, while in positive controls (n = 2) the sealer was not removed. AH Plus removal was evaluated by SEM, and a score system was applied. Data were analyzed by Kruskal–Wallis and Dunn tests. None of the solutions tested was able to completely remove AH Plus from the dentin of the pulp chamber. Amyl acetate performed better than 95% ethanol and isopropyl alcohol (p < 0.05), but not better than acetone (p > 0.05) in removing the sealer from dentin. No significant differences were observed between acetone, 95% ethanol, and isopropyl alcohol (p > 0.05). It was concluded that amyl acetate and acetone may be good options for cleaning the pulp chamber after obturation with AH Plus. SCANNING 35:17‐21, 2013. © 2012 Wiley Periodicals, Inc.     

High-performance base fluids for environmentally adapted lubricants

Future lubricants have to be more environmentally adapted, have a higher level of performance, and lower total life cycle cost (LCC) than presently used lubricants. To be able to formulate those lubricants, the properties of the base fluids have to be well known. Base fluid properties that influence the formulated lubricant performance could be divided into three different groups. These groups are: physical, chemical, and film formation properties. In this study, properties from all of these groups are investigated to improve the understanding on thier influence on base fluid overall performance.There are more or less environmentally adapted base fluids available for formulation of lubricants. They could be divided into different groups, mineral, semi–synthetic, and synthetic fluids. Synthetic fluids could be of different types: polyalpha olefins (PAO), synthetic ester, polyglycols, and others. The most interesting group for formulation of environmentally adapted lubricants are the synthetic esters. In this study, the properties for a large number of environmentally adapted ester base fluids are studied in detail. The tested properties relate to the macroscopic/molecular behavior and include: viscosity–temperature—pressure effects, η(p,T), thermal conductivity, λ(p,T), and heat capacity per unit volume, ρc_p(p,T). The film formation capability in elasto-hydrodynamic contacts is also studied. Different connections between the molecular structure and the performance of the fluids are discussed. As an example, it is found that a large number of carboxylate groups in the ester molecule improve the thermal properties, and thereby a thicker lubricating film could be maintained in highly loaded, high-slip contacts.     

A Multichannel Acoustooptical Deflector with a Planar Delay-Line Structure for Ultrasound Excitation

Results are presented from the development and experimental study of an eight-channel acoustooptical deflector with central frequency f ₀ = 1000 MHz and bandwidth Δf _Σ = 500 MHz within the limits of a 6-dB nonuniformity of diffraction efficiency, the maximum value of which is η ≈ 0.35%/W. In the deflector, a flat spiral delay-line structure excites ultrasound from the surface of a Z-cut LiNbO₃ piezoelectric crystal. The technical parameters of the deflector are discussed, as are the optical, microwave electrical, and acoustical aspects of its construction.__________Translated from Pribory i Tekhnika Eksperimenta, No. 4, 2005, pp. 95–100.Original Russian Text Copyright © 2005 by Rozdobud’ko, Shibaev, Pelipenko.     

A Dosimeter for On-line Dose Rate Monitoring Based on a Natural Diamond Detector

The structure and principle of operation of a dosimeter for on-line dose rate monitoring (DOM) are considered. The DOM provides real-time measurements of the absorbed -ray and electron dose rates, monitors relative distributions of radiation fields in radiotherapy facilities, and controls the radiation characteristics of radiotherapeutic equipment during its adjustment, certification, and service. The dosimeter can measure the dose absorbed in a certain period of time. Compared to conventional dosimeters based on air ionization chambers and silicon semiconductor detectors, the DOM has a number of advantages: dose-rate measurement linearity, energy independence of radiation detection in the range of 0.8–20 MeV for -rays and 8–20 MeV for electrons, high sensitivity compared to air ionization chambers, high radiation and thermal stability, and the small size of the device. The detecting element of the dosimeter is manufactured from a tissue equivalent to a biological material. The operating ranges of dose rate measurements are 10^–3–10 Gy/min and 10^–2–10² Gy/min. The DOM measurement error is <2%. Radiation therapy is the dosimeter field of application.     

Tribological characterization of environmentally adapted ester based fluids

Fundamental properties of six synthetic ester base fluids, suitable for the formulation of environmentally adapted lubricants, have been investigated. High pressure viscosity data for the test fluids were obtained through experimental measurements with a high pressure Couette rheometer. The temperature, pressure and viscosity data η(p, T) were parameterized against the Roelands pressure–viscosity equation. Thermal conductivity and specific heat capacity data were obtained using a transient hotwire method, and the EHD friction coefficient, γ, was obtained experimentally as well. The results from these measurements are reported, and the correlation between thermal properties, molecular structure, and the fluid rheology parameters, of the test fluids are discussed.     

Calcium supplementation in colorectal cancer prevention: A systematic meta-analysis of adverse events

Despite the multiple systematic reviews and meta-analyses accumulating evidence on the preventive effect of calcium supplementation for colorectal cancer, most of the associated adverse effects are not systematically analyzed. The aim of the study is evaluating adverse events associated with calcium supplementation for colorectal cancer prevention through a systematic meta-analysis. We searched Medline, PubMed Central, EMBASE (Excerpta Medica database), Scopus, Cochrane Central Register of Controlled Trials, and Web of Science published in English from database inception up to 31 July 2019. In the current systematic meta-analysis, we included human studies (including cohort studies, clinical trials, case-control studies) on supplementation of calcium in patients with or at risk of colorectal cancer. Assessment of the quality of included studies was performed by Jadad score. Information on the patient population, number of enrolled subjects in each group, dose of calcium supplementation, duration of calcium supplementation, and reported adverse events were gathered. The data were pooled for incidence rates for any adverse event during the study period regardless of causality association. We identified 6 studies, comprising 4583 participants that met the inclusion criteria. Meta-analysis on pooled incidence rates for adverse event during study period showed no statistically significant increased risk for cancer (OR = 0.92, 95% CI: 0.70–1.21, P = 0.577; I² = 0.0%, P = 0.731), coronary revascularization (OR = 1.12, 95% CI: 0.79–1.59, P = 0.492; I² = 0.0%, P = 0.957), myocardial infarction (OR = 0.81, 95% CI: 0.34–1.91, P = 0.634; I² = 67.9%, P = 0.047), stroke (OR = 0.75, 95% CI: 0.42–1.33, P = 0.332, I² = 0.00%, P = 0.717), Transient Ischemic Attack (TIA) (OR = 1.37, 95% CI: 0.28–6.51, P = 0.692, I² = 81.9%, P = 0.002), urolithiasis (OR = 1.23, 95% CI: 0.75–2.01, P = 0.410; I² = 0.0%, P = 0.851), fracture (OR = 0.98, 95% CI: 0.70–1.37, P = 0.938; I² = 37.8%, P = 0.152) and death (OR = 1.05, 95% CI: 0.71–1.56, P = 0.786, I² = 12.2%, P = 0.317) in patients receiving calcium supplementation for colorectal cancer prevention compared to control. Based on the results of Egger test, publication bias was not observed among the studies (P = 0.262). The current result of the meta-analysis on human studies reporting adverse events associated with calcium supplementation for the prevention of colorectal cancer demonstrated no statistically significant increased risk for the development of adverse events compared to control groups.     

Effect of surface topography of scraped machine tool guideways on their tribological behaviour

Tribological behaviour of two kinds of scraped surface topography of machine tool guideways — the conventional form named ‘narrow-deep’ scraping and an improved form termed ‘wide-shallow’ scraping — is described. Behaviour is compared under the following conditions: average pressure p = 0.135−0.675 kgf cm⁻² and sliding velocity V = 15−600 mm min⁻¹. In comparison with narrow-deep scraping of slideways, wide-shallow scraping may reduce the friction coefficient by about 50–90%, relieve the phenomenon of stick-slip, and increase the amount of table floating. Consequently, the positioning accuracy of the machine tool feed drive system and the wear durability of guideways can be expected to be improved greatly. The amount of scraping work might be decreased to less than . An attempt is made to explain the above results from the viewpoint of hydrodynamic lubrication and to summarize the characteristics of the two kinds of scraped surface mentioned above. Based upon a series of experiments, the authors propose that in evaluating the performance of guideway surfaces, the concepts of oil-film-forming ability and oil-film-retaining ability are helpful.     

Optimum design of multi-ring composite flywheel rotor using a modified generalized plane strain assumption

A numerical method for calculating the stress and strength ratio distribution of the hybrid rim-type composite flywheel rotor is presented with a consideration of the thermally induced residual stresses. The axisymmetric rotor is divided into several rings and the stiffness matrix for each ring is derived by solving the radial equilibrium equation and the stress–strain–temperature relations. The ring stiffness matrices are assembled into a symmetric global matrix satisfying the continuity equations at each interface with the assumptions of a modified generalized plane strain (MGPS). In the MGPS, the z-directional axial strains are assumed to vary linearly along the radial direction; ε_z=ε₀+ε₁r. The conditions that the z-directional force and the circumferential moment resultants vanish are thus used to solve the z-directional axial strains as well as the radial and circumferential strains. After solving the strain distributions, the on-axis stresses and the strength ratios are calculated at each ring. Three-dimensional finite element method (3D FEM) is then used to verify the accuracy of the present method. The results are also compared with those based on the assumption of a plane stress (PSS). In this case, the analysis of MGPS better matches with 3D FEM results than PSS. An optimum design is then performed maximizing total stored energy (TSE) with the thickness of each composite rim as design variables. The optimal design obtained in this study, which considers material sequence, provides a more effective way of maximizing TSE. It is found that the consideration of the residual stress in the design of the hybrid flywheel rotor is crucial. The result of the optimal designs shows that TSE with consideration of ΔT reduces by about 30%.     

Predictive model to estimate the stress–strain curves of bulk metals using nanoindentation

Many studies have shown that finite element modeling (FEM) can be used to fit experimental load–displacement data from nanoindentation tests. Most of the experimental data are obtained with sharp indenters. Compared to the spherical case, sharp tips do not directly allow the behavior of tested materials to be deduced because these produce a nominally-constant plastic strain impression. The aim of this work is to construct with FEM an equivalent stress–strain response of a material from a nanoindentation test, done with a pyramidal indenter. The procedure is based on two equations which link the parameters extracted from the experimental load–displacement curve with material parameters, such as Young's modulus E, yield stress Y₀ and tangent modulus E_T. We have already tested successfully the relations on well-known pure metallic surfaces. However, the load–displacement curve obtained using conical or pyramidal indenters cannot uniquely determine the stress–strain relationship of the indented material. The non-uniqueness of the solution is due to the existence of a characteristic point (ε_c, σ_c); for a given elastic modulus, all bilinear stress–strain curves that exhibit the same true stress σ_c at the specific true strain ε_C lead to the same loading and unloading indentation curve. We show that the true strain ε_c is constant for all tested materials (Fe, Zn, Cu, Ni), with an average value of 4.7% for a conical indenter with a half-included angle θ=70.3°. The ratio σ_c/ε_c is directly related to the elastic modulus of the indented material and the tip geometry.     

Effect of Chenopodium ambrosioides on the healing process of the in vivo bone tissue

The focus of this double‐blind randomized study was on evaluating the effect of an aqueous extract of Mastruz (Chenopodium ambrosioides L.) on the bone repair process in vivo. In total, 36 male Wistar rats were randomly selected for this study, and divided into 3 groups (n = 12): Group HS (Hemostatic Sponge), Group SM (Hemostatic Sponge with Mastruz) and Group BC (Blood Clot). In each animal, bone defects measuring 2 mm in diameter were performed in both tibias for placement of the substances. After 3 and 10 days, the animals were sacrificed, and the tissues were analyzed under an optical microscope relative to the following events: inflammatory infiltrate; necrosis; young fibroblasts; osteoclastic and osteoblastic activity; endosteal and periosteal bone formation; and bone repair. The results were assessed by using Kruskal–Wallis and Mann–Whitney tests (p < .05). Inflammatory infiltrate demonstrated difference between Groups SM and BC in the time interval of 3 days (p = .004); an event related to the presence of the fibrin sponge and liquid of the extract, which induced a foreign body initial reaction. The presence of young fibroblasts (p = .003), osteoclastic (p = .003), and osteoblastic (p = .020) activity was statistically significant between Groups HS and BC in the time interval of 10 days; performance was related to the presence of the sponge within bone. As regards injured bone tissue repair, Group SM demonstrated a higher level of regenerative capacity (p = 0.004), due to a larger quantities of endosteal and periosteal bone formation, demonstrated in Group SM. The aqueous extract of mastruz stimulated bone neoformation, presenting wound closure with bone tissue at the end of 10 days.     

Noninvasive Quantification of Cutaneous Oedema in Patch Test Reactions by Fiber Optic Near-Infrared Fourier Transform Raman Spectroscopy

The major aim of the present study was to quantitatively differentiate various degrees of positive patch test reactions by estimating relative water content noninvasively using fiber optic near-infrared Fourier transform (NIR-FT) Raman spectroscopy. The specific intent was to examine its technical applicability and reproducibility in reading patch tests at 48 and 72 hr. Instrumental measurements at 63 patch test sites were compared visually in 19 patients with suspected allergic contact dermatitis. Raman spectra were measured in vivo in skin reacting to patches on the back using a fiber optic technique. Negative (–), doubtful (?+) and positive patch test reactions (+; ++/+++) could be separated by means of measured differences in absolute values of the 3250 cm^–1 peak (ratio I₃₂₅₀/I₂₉₄₀): at 48 hr the mean increases were 0.31(–), 0.40(?+); 0.45(+); 0.69(++/+++) and at 72 hr they were 0.31(–); 0.34(?+); 0.42(+); 0.60(++/+++). At 48 hr significant differences (p<0.05) were shown between all reactions, but not between negative and doubtful reactions at 72 hr. These findings indicate that cutaneous oedema in patch test reactions can be noninvasively quantified based on positive patch test reactions by NIR-FT Raman spectroscopy, with continuous data grading of reaction intensity suitable for clinical studies at 48 and 72 hr. We also demonstrated good technical reproducibility of patch test reactions evaluation by NIR-FT Raman spectroscopy at 48 and 72 hr, showing that this method can be used to monitor the dynamics of these reactions and display the results spectroscopically.     

The Spatial Reconstruction of Grain Coordinates in the Emulsion Tracker

It is shown that the use of formulas of paraxial optics in the spatial reconstruction of grain coordinates which are measured by a microscope with a wide-aperture objective lens in an emulsion tracker plate may lead to a systematic error. The error vanishes, if, in these formulas, a single phenomenological parameter a _eff with a value lying between zero and the numerical aperture of the lens. The results of the combined analysis of a series of film thickness measurements for films with various refractive indices n allowed us to estimate a _eff parameters for several lenses. With no allowance for correction, the relative systematic error is +0.6% in measurements with a TIYODA 60^×/1.0 immersion lens in a plastic layer with n _pl = 1.49 and –0.2% in measurements in an emulsion with n _em = 1.53 with the same objective lens. Measurements with a LOMO 40^×/0.65 lens yielded corresponding errors of –3.4 and –3.6%.     

Stability, bifurcation and chaos of closed flexible cylindrical shells

Complex vibrations of closed cylindrical shells of infinite length and circular cross-section subjected to transversal local load in the frame of the classical non-linear theories are studied. A transition from partial differential equations (PDEs) to ordinary differential equations (ODEs) is carried out using a higher-order Bubnov–Galerkin approach and Fourier representation. On the other hand, the Cauchy problem is solved using the fourth-order Runge–Kutta method.In the first part of this work, static problems of the theory of closed cylindrical shells are studied. Reliability of the obtained results is verified by comparing them with the results taken from literature. The second part is devoted to the analysis of stability, bifurcation and chaos of closed cylindrical shells. In particular, an influence of sign-changeable external pressure and the control parameters such as magnitude of pressure measured by ₀, relative linear shell dimension λ=L/R, frequency ω_p and amplitude q₀ of external transversal load, on the shell's non-linear dynamics is studied.     

Meta-analysis evaluation of the treatment of neonatal hypoxic– ischemic encephalopathy with ganglioside

The efficacy and safety of ganglioside in the treatment of neonates who suffer from hypoxic–ischemic encephalopathy (HIE) needs to be fully evaluated. We searched the following databases: PubMed, ScienceDirect, LISTA, CNKI, Chinese biomedical literature database and Wanfang digital journals of full-text database to determine the inclusion and exclusion criteria of papers and a total of 12 papers were included after quality evaluation. Then we conducted the meta-analysis with RevMan5.0 software. The results showed that compared with the control group, the abnormal rate declined in the ganglioside-treated group (relative risk (RR)=0.27, 95% confidence interval (CI)= 0.05– 1.96). NBNA records of the 7, 10–14d neonates were improved effectively: RR (95% CI) were 2.28 (0.86–3.42) and 2.53 (1.04–2.92) respectively. Neural system sequelae incidence was reduced significantly: RR (95% CI) = 0.35: (0.15–0.79). Ganglioside treatment could effectively reduce the abnormality rate of head size, improve the neurological score, reduce the incidence of neurological sequelae, and significantly prompt clinical recovery for neonates with HIE.