Cylinder Method Research Articles

Mixed Alkali Effect in Viscosity of CaO-SiO2-Al2O3-R2O melts

The mixed alkali effects of Li2O, Na2O, and K2O on viscosity of CaO-SiO2-Al2O3 melts are investigated by rotating cylinder method. It is found that the single addition of Li2O, Na2O, or K2O to CaO-SiO2-Al2O3 melt will reduce the viscosity of melt, regardless of the Al2O3 content, while the degree of reduction follows the sequence of Li2O > Na2O > K2O. For melts containing two alkali oxides, viscosity monotonically decreases when one alkali oxide is replaced by another at all temperature investigated in this paper, but no extrema of viscosity is found like the behavior of electrical conductivity. In addition, the extrema are not found in the slag containing three alkali oxides if changing their relative contents but keeping their total contents constant. Raman spectroscopy is used to illustrate the relationship between viscosity and structure of melt and it is found that degree of polymerization is the major factor affecting the viscosity of melt.

Broad-spectrum antimicrobial activity of wetland-derived Streptomyces sp. ActiF450.

The increased incidence of invasive infections and the emerging problem of drug resistance particularly for commonly used molecules have prompted investigations for new, safe and more effective microbial agents. Actinomycetes from unexplored habitats appear as a promising source for novel bioactive compounds with a broad range of biological activities. Thus, the present study aimed to isolate effective wetland-derived actinomycetes against major pathogenic fungi and bacteria. Water samples were collected from various locations of Fetzara Lake, Algeria. Thereafter, an actinomycete designated ActiF450 was isolated using starch-casein-agar medium. The antimicrobial potential of the newly isolated actinomycete was screened using the conventional agar cylinders method on Potato Dextrose Agar (PDA) against various fungal and bacterial pathogens. A wetland-derived Streptomyces sp. Actif450 was identified as Streptomyces malaysiensis based on its physiological properties, morphological characteristics, and 16S rDNA gene sequence analysis. The antimicrobial activity of Streptomyces sp. ActiF450 showed a potent and broad spectrum activity against a range of human fungal pathogens including moulds and yeasts, such as Arthroderma vanbreuseghemii, Aspergillus fumigatus, A. niger, Candida albicans, C. glabarta, C. krusei, C. parapsilosis, Fusarium oxysporum, F. solani, Microsporum canis, Rhodotorula mucilaginous and Scodapulariopsis candida. In addition, high antibacterial activity was recorded against pathogenic staphylococci. The novel Streptomyces sp. ActiF450 may present a promising candidate for the production of new bioactive compounds with broad-spectrum antimicrobial activity.

Effects of MgO/Al2O3 ratio on viscous behaviors and structures of MgO–Al2O3–TiO2–CaO–SiO2 slag systems with high TiO2 content and low CaO/SiO2 ratio

Abstract The effects of MgO/Al2O3 ratio on the viscous behaviors of MgO–Al2O3–TiO2–CaO–SiO2 systems were investigated by the rotating cylinder method. Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag. The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al2O3 ratio increases from 0.82 to 1.36. The break point temperature and liquidus temperature of slag initially decrease and subsequently increase. The complex viscous structures are gradually depolymerized to simple structural units. In conclusion, with the increase of MgO/Al2O3 ratio, the degree of polymerization of slag decreases, which improves the fluidity of slag. The variations of liquidus temperature of slag lead to the same changes of break point temperature.

Buckling Behavior of Horizontal Hydraulic Cylinder Articulated at Both Supports

The existing critical buckling load calculation methods of horizontal hydraulic cylinder failed to fully reflect the initial boundary conditions and some critical influence factors, resulting in an unjustified critical buckling load. A new method to analyze the buckling behavior of the horizontal hydraulic cylinder articulated at both supports is developed on basis of large deflection theory and Timoshenko beam theory. Friction at supports, self-weight and initial misalignment by clearances are taken into account. Friction moments of supports are built according to Hertz contact theory. Bending stiffness of cylinder-rod junction is figured out in terms of elastic deformation theory. Runge–Kutta and Newton–Raphson method are used in numerical calculation for the critical buckling load. Practical calculation and stability test are carried out to verify the necessity of considering large deflection and shear effect in the proposed method. Experimental work shows the critical buckling load by the proposed method can well match to that by stability test with 0.55% deviation. Moreover, the numerical calculation results demonstrate that the friction moment of the support at piston rod end is crucial for the buckling behavior. The critical buckling load rises increasingly as the friction coefficient [Formula: see text] rises. As the friction coefficients [Formula: see text] increases from 0 to 0.020, the rise rate of critical buckling load increases from 1.782% to 8.055% per 0.001. And the clearance at cylinder-rod junction is a minor factor on the critical buckling load. As the clearances increase by 10 times, the critical buckling load decreases by 3.542%.

Viscosity behaviour of silicate melts during cooling under variable shear rates

The viscosity of a crystal-bearing shoshonite from Vulcanello (Aeolian Archipelago, Italy) was measured using the concentric cylinder method. Experiments were performed in the temperature interval from superliquidus (1573 K) to 1373 K with the aim to investigate the rheological response of the magma during variable cooling rate (i.e. 1000, 100 and 10 K/h) and shear rate (0.01, 0.1 and 1 s−1). In one experiment, with a cooling rate of 10 K/h and shear rate of 1 s−1, clinopyroxenes (ca. 11 vol.%) with hopper texture crystallized. One further experiment was performed for a longer time with a cooling rate of 100 K/h and shear rate of 1 s−1 to the final temperature of 1323 K. In this case, the final product showed skeletal crystals of pyroxenes (ca. 17 vol.%) and an apparent viscosity of 1.10 × 104 Pa s, which was very close to the experiment performed at 10 K/h and shear rate of 1 s−1 to 1373 K (1.18 × 104 Pa s). The comparison between experiments performed at cooling rate of 100 K/h, and finally quenched at to 1373 and 1323 K, respectively, showed that a temperature decrease of 50 K produces an increase in the apparent viscosity of ca. 1 log unit due to the transition from crystal-free to crystal-bearing melts.This study provides new data on apparent viscosity variation as cooling and shear rates vary in a crystallizing magmatic system. Results show that, on average, the viscosity of a shoshonitic system can increase by about two orders of magnitude due to temperature decrease from 1573 to 1373 K and the incipient crystallization occurring at the lowest temperatures. Finally, the results confirm that crystal nucleation and growth kinetics, as well as magma viscosity, are controlled by the dynamic state of the system.

Instability of saturated granular materials in biaxial loading with polygonal particles using discrete element Method (DEM)

Sandy soils may become unstable under loading which causes large deformations and consequently, impose damages to existing structures. In this research, Discrete Element Method (DEM) is used to simulate 2D drained and undrained behavior of polygonal granular materials to investigate instability occurrence. The so-called cylinder method is applied to simulate the undrained behavior that a pipe is assumed between neighboring pores to allow fluid flow. The applicability of this method was evaluated with constant-volume approach. The advantage of the cylinder method is to assess the distribution of fluid pressure. Comparison of the results indicate good match. Based on both drained and undrained simulations, a unique critical state line was obtained; however, the position of instability line was influenced by the initial void ratio. At the onset of potential instability, the central pore pressure increases highly; however, it reduces afterwards and the fluid pressure is almost distributed uniformly throughout the sample.

Influence of TiO2 on the melting property and viscosity of Cr-containing high-Ti melting slag

A study on the melting and viscosity properties of the chromium-containing high-titanium melting slag (CaO-SiO2-MgO-Al2O3-TiO2-Cr2O3) with TiO2 contents ranging from 38.63wt% to 42.63wt% was conducted. The melting properties were investigated with a melting-point apparatus, and viscosity was measured using the rotating cylinder method. The FactSage 7.1 software and X-ray diffraction, in combination with scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS), were used to characterize the phase equilibrium and microstructure of chromium-containing high-titanium melting slags. The results indicated that an increase in the TiO2 content led to a decrease in the viscosity of the chromium-containing high-titanium melting slag. In addition, the softening temperature, hemispheric temperature, and flowing temperature decreased with increasing TiO2 content. The amount of crystallized anosovite and sphene phases gradually increased with increasing TiO2 content, whereas the amount of perovskite phase decreased. SEM observations revealed that the distribution of the anosovite phase was dominantly influenced by TiO2.

Development of manufacturing technology and quality control methods for solid-drawn cylinders from AMg5 alloy

Development of manufacturing technology and quality control methods for solid-drawn cylinders from AMg5 alloy

Electric hybrid control method of assembly line robot based on PLC

With the development of modern industry, manipulators have become a kind of mechanical equipment widely used in assembly lines, which not only can improve production efficiency and product quality, but also improve working conditions. Taking the polar co-ordinate manipulator in the automated assembly line as the research object, the programmable logic contoller (PLC) based assembly line manipulator electrical hybrid control method is analyzed. The assembly line robot includes the base, the stepping motor to drive the rotation of the waist, the cylinder controlled arm and the gripper, based on the polar co-ordinate manipulator action requirements, FX2N series programmable logic contoller is selected to analyze programmable logic contoller based stepper motor, pneumatic servo positioning device, pitch cylinder and gripper control method in detail. The components of the assembly line manipulator are organically combined by programmable logic contoller to realize the electrical mixing control of the assembly line manipulator. The experimental results show that the assembly success rate and breakage rate of the assembly line robot controlled by the proposed method are 99.25% and 0.85%, respectively. The transmission performance and anti-noise performance are better than the comparison method, compared with the traditional method, this method has significant performance advantages in control accuracy, cost, practicability and so on and it has a good application prospect.

The liquid AlCu4TiMg alloy: thermophysical and thermodynamic properties

In this study, some structure-sensitive thermophysical properties, namely, thermal conductivity, thermoelectric power, density and surface tension of liquid AlCu4TiMg alloy, as one of the most promising cast alloys to fabricate components for cars, aircraft and other complex engineering products, were investigated. Thermoelectric power was measured in a wide temperature range by the four-point contact method. Thermal conductivity was investigated by the steady-state concentric cylinder method. The oscillating drop technique combined with electromagnetic levitation was used for density and surface tension studies. The results obtained are compared with experimental and calculated data from literature for pure aluminum.

Influence of Nb2O5 and basicity on the viscosity and structure of CaO-SiO2-Nb2O5-CeO2-CaF2 slag system

In order to utilize niobium concentrate of Bayan Obo effectively, the effect of Nb2O5 and basicity on the viscosity of CaO-SiO2-Nb2O5-5.0 wt.% CeO2-5.0 wt.% CaF2 slag system was studied from 1653 to 1813 K in reducing atmosphere by rotating cylinder method. For the same condition, the as-quenched samples were investigated through X-ray diffraction and Raman spectroscopy. The results show that the viscosity, break temperature and activation energy of viscous flow decrease with the increase of Nb2O5 and basicity. Raman spectra show that the Nb4+ ions exist in the form of [NbO6] octahedron with different distortion and little [NbO4] tetrahedron in the slags. The Nb2O5 addition and basicity lower the degree of polymerization, where the complex Si-O network is depolymerized into simple structural units.

Effect of MgO and BaO on viscosity and structure of blast furnace slag

The viscosity was measured by the cylinder method to investigate the effect of MgO and BaO on the viscous behavior of CaO-SiO2-Al2O3-MgO-BaO slags (CaO/SiO2 = 1.05, 7–10 wt%MgO, 0–3.5 wt%BaO). Based on the experimental data, the free running temperature and the activation energy were calculated to analyze the changes of characteristic of viscosity flow. The Fourier transformation infrared (FTIR) and Raman spectra were used to provide the information about the variation of slag structure. The results indicate that the viscosity, free running temperature, as well as activation energy decrease with the increase of MgO content in range of 7 wt%–10 wt%, and increase at BaO content from 0 wt% to 3.5 wt%. MgO provides free oxygen (O2−) to reduce the polymerization degree of slag and decreases the viscosity. However, the addition of BaO tends to form complicated structure and increase the viscosity. When BaO is added into slag, Ba2+ and O2− simultaneously influence the slag structure. O2− can break the Si-O bonds, and thus decrease the polymerization degree of slag. On the other hand, the charge compensation of Ba2+ can form complex aluminate-silicate structure and increase the viscosity of the slag. And the strong charge compensation effect that BaO acted is more dominated in the changes of slag structure.

Estimation of limit state for quasi-isotropic [90°/± 45°/0°]S AS4/3501-6 carbon/epoxy under uniaxial and biaxial loads

Background. Composite materials, in particular laminated carbon fiber reinforced with high-strength unidirectional fibers, are widely used in many industries. The active development of the production of fibers and matrices leads to a large number of new materials and their widespread using in production requires effective techniques for estimate the ultimate state of carbon fiber under various load conditions.Objective. Comparative analysis of strength estimation methods using the example of laminated carbon fiber with AS4 carbon fiber and a 3501-6-epoxy matrix reinforcing pattern [90 ° / ± 45 ° / 0 °] s under UNIAXIAL AND BIAXIAL LOADS conditions using an analytical model of the degradation of the mechanical properties of the composite layer proposed in the work of M.K. Kucher and M.M. Zarazovskii and the method of numerical simulation in the software environment ANSYS Workbench.Methods. The mechanical characteristics of the carbon fiber monolayer were previously calculated using various analytical methods: the mixture rule, the coaxial cylinder method, the Kilchinsky model, and the Vanin method. The stress calculations were compared with tests results published by a group of authors (P. D. Soden, M. J. Hinton & A. S. Kaddour).Results. The application boundaries for numerical and analytical methods for assessing the strength of carbon plastics in a plane and linear stress state are analyzed.Conclusions. Based on the studies, it was concluded that the model of degradation of the mechanical properties of the layer requires improvement under conditions of a negative ratio between the main stresses. The effectiveness of using the ACP(Pre) and ACP(Post) modules of the ANSYS Workbench software environment for estimation the ultimate state of laminated carbon fiber reinforced plastic under uniaxial and biaxial loads conditions is confirmed.

Vapor thermal conductivity of R-125/R-134a (84.6/15.4) mixture

The vapors thermal conductivity of binary mixture R-125/R134a (84.6/15.4) was measured with a coaxial cylinders method in the temperature range of 305–412 K and the pressure range of 0.1–1.7 MPa. The thermal conductivity as a function of pressure and temperature was considered. The correlations for thermal conductivity on dew line and in ideal gas state are presented.

Effect of Wearing Plus Lens on Reading Ability of College Students with Normal Binocular Function

Purpose : The purpose of this study was to investigate the effect of wearing plus lens on reading ability in college students with normal binocular function. Methods : Accommodative lag and reading ability were measured in 42 college students with normal binocular function, and no eye disease. For the control lag test the subjective cross cylinder method was applied, and for the reading ability the duration of fixation, number of regression, saccadic in return sweep and reading rate were measured using the Readalyzer. The subjects reading abilities were measured before and after with the plus lens corresponding to the amount of accommodative lag. Statistical analysis using SPSS version 21.0(SPSS Inc, Chicago, IL, USA) was used to analyze the change of the ability before and after wearing the plus lens through a paired t-test. Results : When the subjects wore the plus lens corresponding to the accommodative lag, the duration of fixation was slightly increased, the number of regression was significantly decreased, and the reading rate was significantly increased. Conclusion : It was considered that wearing plus lens with low refractive power may affect the time to look at words during reading. During reading with the lens, it may also have an effect changes such as reducing the number of regression and increasing the reading rate.

Evaluation of the mucoadhesive strengths of Abelmoschus esculentus and Irvingia gabonensis gums for possible application in veterinary vaccine delivery: the effect of extraction methods

ABSTRACTThis study evaluates the effects of different gum extraction methods on the mucoadhesive strengths of Abelmoschus esculentus (AE) and Irvingia gabonensis (IG) gums and the release of vaccine antigen in vaccine–gum formulations. AE and IG gums were extracted employing previously documented methods with acetone or sodium chloride (NaCl) and either oven-dried or freeze-dried. Gum extracts were analyzed for mucoadhesive strengths using a modified rotational cylinder method on animal mucosa. The time taken to detach from the mucosa was taken as the Peak Adhesion Time (PAT). The gum extracts were charged with Peste des petits ruminant vaccine and the antigen release was evaluated using agar gel immunodiffusion technique. The means of the PATS were analyzed using Mann-whitney t-test at p < .05. The NaCl extracted and freeze-dried IG gum showed sustained mean PATs of 1766 ± 73 s; 2116 ± 101 s; 7044 ± 117 s, while the oven-dried IG gum and both AE gums showed short-lived average PATs. Vaccine-gum formulations of IG at ratios 2:1, 1:1 & 1:2 had strong positive reactions while only that of AE at 2:1 showed a strong positive reaction. This study shows that NaCl extracted and freeze-dried IG gum has immunomodulatory potential for mucoadhesive vaccine delivery in ruminants.

Kirchhoff Approximations for the Forward-Scattering Target Strength of Underwater Objects

Kirchhoff approximations for the forward-scattering target strength of underwater objects are developed by combining Babinet’s principle and the Kirchhoff integral, where theoretical formulations and a numerical implementation are given in detail. The Kirchhoff approximation is found to be a high-frequency physical acoustic approximation. The forward-scattering target strength versus frequency and the spatial angles for spherical objects, prolate spheroids and the Benchmark Target Strength Simulation Submarine (BeTSSi-Sub) model are obtained by the Kirchhoff approximation and compared with results from theory, the deformed cylinder method (DCM) and the boundary element method (BEM). The Kirchhoff approximation shows considerable agreement with the theoretical and numerical approaches in a region of [Formula: see text] from the rigorous forward-scattering direction. The forward-scattered field contour and the corresponding directivity for the BeTSSi-Sub model are also calculated as a demonstration. Mode coupling caused by the simulated target is clearly revealed. The results indicate that the Kirchhoff approximation can predict the forward-scattering target strength of complex underwater objects.

Insight into the Relationship Between Viscosity and Structure of CaO-SiO2-MgO-Al2O3 Molten Slags

This article elucidates the quantitative relationship between viscosity and structure in a basic slag system of CaO-SiO2-MgO-Al2O3 and focuses on the role of Al2O3. Slag viscosity was measured by the rotating cylinder method, and structural information was obtained using Fourier transformation infrared, Raman and magic angular spinning nuclear magnetic resonance (MAS-NMR) techniques. The results show that, as the Al2O3 content increased, slag viscosity increased initially and decreased afterwards, directly indicating that Al2O3 had an amphoteric effect on slag viscosity. The Raman spectra verified that with increasing Al2O3 content, the concentrations of Q0(Si) and Q2(Si) decreased first and then increased, while that of Q1(Si) kept increasing and that of Q3(Si) increased first and then decreased. The 27Al MAS-NMR spectra proved that the mole ratios of AlO5 and AlO6 to AlO4 kept increasing with the increase of Al2O3 content, and, overall, Al2O3 changed from a network former to a network modifier. The relationship between the viscosity and structure of the molten slags was further analyzed quantitatively based on the modified (NBO/T), denoted as (NBO/T)′, and we found a fine linear correlation between the logarithm of viscosity and (NBO/T)′. Moreover, the variations of thermodynamic properties of this system also indirectly supported the present experimental results.

Roles of MgO and Al2O3 on the Viscous and Structural Behavior of Blast Furnace Primary Slag, Part 1: C/S = 1.3 Containing TiO2

This research provides fundamental insight into the roles of MgO and Al2O3 on the viscous and structural behaviors of CaO−SiO2−MgO−Al2O3−10 mass% TiO2−5 mass% FeO (CaO/SiO2 = 1.3) system primary blast furnace slag. The slag viscosity is measured by the rotating cylinder method, which is essential to the efficient and stable operation of a blast furnace. The network structure characterization of the quenched vitreous samples was conducted using Fourier Transformation Infrared (FTIR) and Raman spectroscopy. Usual viscous behaviors (that the slag viscosity and the activation energy decrease or increase with increasing MgO or Al2O3 content) were observed, corresponding to changes in the network structure certified by FTIR and Raman analyses. It seems that the addition of MgO and Al2O3 prefers to modify the Si−O and Ti−O network in the present slag. When the slag composition reaches 10% MgO and 12% Al2O3, unexpected viscous behaviors (that MgO increases viscosity and Al2O3 decreases viscosity) are discovered. The roles of MgO and Al2O3 could be interpreted by changes in the arrangement structure of ions in liquid, corresponding to changes in the primary equilibrium phase region determined in phase diagrams and variation in the difference between the experimental and liquidus temperature, respectively.

A smeared stiffener based reduced-order modelling method for buckling analysis of isogrid-stiffened cylinder

• A reduced-order modelling method is proposed for nonlinear stability of isogrid-stiffened cylinders. • The reduced order model is constructed based on the smeared stiffener model. • Mode selection criteria are developed in the proposed method for imperfect cylinders. • Computational costs are significantly reduced in buckling and imperfection sensitivity analyses. Thin-walled isogrid-stiffened structures have been widely used as highly efficient structural components in aerospace engineering. In this work, the stability behavior of isogrid-stiffened cylinder is analyzed using the smeared stiffener model based reduced-order modelling (SSM-ROM) method. The smeared stiffener method proposed based on mechanical characteristics of isogrid-stiffener cell is applied to facilitate the finite element(FE) modelling of structure. The reduced-order models constructed based on Koiter asymptotic expansion are extended to be applicable for the smeared stiffener model. Mode selection criteria for cylinders with measured geometric-shape imperfections are developed to lower the computational cost in construction of the reduced-order model. The proposed method is implemented into the finite element framework and achieved completely using the in-house codes. The isogrid-stiffened cylinders with two different configurations(strong or weak stiffeners) are considered to validate the performance of the proposed method. Linear and nonlinear buckling analyses are first applied to test the numerical accuracy of the smeared stiffener model. The sensitivity of the buckling load in terms of magnitude of initial imperfections is then carefully studied using three different geometric imperfection shapes. Numerical results demonstrate the good performance of the proposed method in both structural buckling analysis and imperfection sensitivity analyses.