Cylindrical Case Research Articles

MOVEMENT OF A PARTICLE BY A MOVING VERTICAL AUGER BOUNDED BY A CASING

During the various technological operations in various fields of industry and production, the working bodies of machines and tools interact with particles of technological material. At the same time, the geometric shape of the surface of the working bodies determines the character of the movement of particles on it. Particles of the technological material are often considered as material particles, which is acceptable because of their small dimensions. In this case, inertial forces from the rotation of the material are not taken into account, and as a result, the obtained analytical dependencies of its movement are somewhat approximate, however, it can be applied to a certain extent to the material and determine the direction of further research. A fairly common method of transporting technological material is the use of screws – a curved blade in the form of a strip of a helical conoid. Usually, a screw is moving and limited by a stationary coaxial cylindrical casing. In the article, the movement of a particle inside the vertical structure, which is made up of a cylinder and a coaxial strip of a helical conoid, and which rotates around a common vertical axis, is investigated. The differential equations of the relative movement of the particle along the periphery of the screw have been received. A special case, when the surfaces are stationary, was considered. A qualitative analysis of the obtained equations was made and based on this, the patterns of particle movement along the helical line – the curve of the intersection of the screw with the cylinder – were found. Constructive and kinematic parameters, when the particle moves up during sliding along a helical line or falls down, were found. It was established that if the angle of rising of the curve of the intersection of the limiting cylinder with the surface of the screw is less than or equal to the angle of friction of the particle on it, then the movement of the particle in both directions becomes impossible. This applies to both moving and stationary surfaces. The relative and absolute trajectories of particle movement are constructed in the article.

Impurity effects on binding energy, diamagnetic susceptibility and photoionization cross-section of chalcopyrite AgInSe2 nanotadpole

Recently the interest in chalcopyrite semiconductor nanostructures has increased because of their non-toxicity and their wide direct bandgap. Likewise, structures with non-trivial geometry are particularly interesting because of their electronic, optical, and magnetic properties. In the current article, the finite element method was used in conjunction with the effective mass approximation to theoretically investigate the properties of a chalcopyrite AgInSe2 nanotadpole in the presence of an hydrogen like shallow off-center impurity. The morphology of the nanotadpole gives it excellent hydrodynamic properties and is ideal for a wide range of applications. The probability densities for various impurity positions and energy levels were obtained. The results suggested a strong dependence of the behavior of the electron on the impurity positions and the orientation of the wave function. The investigation of the nanotadpole’s energy spectra and their comparison with the cylindrical and spherical quantum dots suggest that the spectrum has degenerate states similar to the spherical case, however at some ranges, the levels behave similarly to the cylindrical case. The binding energy’s dependence on the nanotadpole’s size and the impurity position was obtained. The dependence of the diamagnetic susceptibility on the impurity position was calculated. An extensive investigation of the photoionization cross-section was carried out for the ground and the first two excited states as the initial states and the first twenty excited states as the final states.

A geometrical optimization and comparison study on the charging and discharging performance of shell-and-tube thermal energy storage systems

Shell-and-tube latent heat thermal energy storage (ST-LHTES) systems have been extensively studied due to their high thermal/cold storage capacity during the charging/discharging process and their wide range of applications. The thermal performance of these systems is heavily dependent on the shape and geometry of the shell part. This research aims to investigate the transient heat transfer of phase change material (PCM) in the vertical ST-LHTES systems during charging (melting) and discharging (solidification) and the impact of geometric design on the heat transfer characteristics and consequently the thermal performance of the system in both processes. For this purpose, phase change heat transfer in a conventional cylindrical shell is compared with conical configurations with arbitrary inclination angles. The different heat transfer characteristics, e.g., the rate of phase change fraction and the energy stored/released, are determined and compared for all systems to evaluate their thermal performance and find the optimal design. The phase change process is also numerically visualized to track the phase change interface during both charging and discharging processes. A dynamic adaptive mesh refinement technique is implemented to capture gradients and simulate phase change front accurately. Depending upon the inclination angle, a favorable result can be achieved for the charging process in conical shape compared with a cylindrical geometry, while inverse results are obtained for the discharging process. In other words, increasing the lateral slope of the shell from a vertical to tilted state enhances the melting process resulting in a faster energy storage rate during the charging process, whereas decreasing this slope leads to better thermal performance for discharging process. The optimum designs can improve the system performance by 52% and 56% for the charging and discharging processes, respectively. A comprehensive experimental setup is developed for the cylindrical case to visualize and compare the charging and discharging process experimentally as well. Results obtained from numerical simulations exhibit similar patterns to experimental visualizations.

Gurney velocity modification for detonation-driven steel cylindrical casings

Detonation-driven experiments for 2,4,6-trinitrotoluene in standard copper cylindrical casings and in 50SiMnVB and 45 steel cylindrical casings with three thicknesses were carried out in this study. The results showed that due to the influences of the coupled loading of the shock waves and the detonation products, the initial velocity of the fragments of the steel cylinders predicted using the Gurney formula and Gurney velocity obtained from a standard cylinder experiment significantly deviated from the experimental observations. This was caused by the difference in the cylinder density and the load coefficient β. Thus, a modified method and model of the Gurney velocity were proposed, and modification coefficients were obtained via a numerical simulation, which provided a means for a more accurate calculation of the initial velocity of fragments of the steel cylinder. Moreover, further analysis showed that at the same β value, the modified Gurney velocity of the copper cylinder was larger than that of the steel cylinder. The modified Gurney velocity of the same cylinders increased with the increase in the β value. The smaller the β value was, the larger the increase in the ratio was. When β > 0.8, the modified Gurney velocity became constant.

Fragments velocity distribution and estimating method of thin-walled cylindrical improvised explosive devices with different length-to-diameter ratios

The fragment velocity distribution of the improvised explosive device (IED) that is commonly made of thin-walled casings filled with explosives is an important parameter in the development of protection structures. In this study, the axial fragment velocity distributions of 10 thin-walled cylindrical casings with different L/D ratios filled with charges were measured and analyzed by orthogonal flash X-ray radiography. The results suggest that the axial rarefaction waves significantly affect the fragment velocity distribution at the L/D ratios less than 1.5. A bivariate 3D empirical model for calculating axial fragment velocity distribution was then constructed by fitting the experimental data with the coupled effect of the axial rarefaction waves included. The general applicability of the estimating method was verified with the experimental data of another set of 7 charges. The average relative error between the calculation results and experiment results is only 4.33%, suggesting that the model is reliable for estimating the fragment velocity distributions of the charges with different L/D ratios. Furthermore, the estimating method has also been verified based on numerical simulation. The numerical results show that the estimating method can be used for the casing with C/M of 0.2∼1.9, which means the potential of the estimating method in engineering applications. Our work can provide a practical guide in assessing the hazards of IEDs in the framework of anti-terrorism engineering.

Thermal endoscope based on cost-effective LWIR camera cores

The implementation of a thermal endoscope based on the LWIR camera cores Lepton and a custom miniaturized electronics is reported. The sensor and the PCB can be inserted into a cylindrical protective case of diameter down to 15mm, inox tube or plastic, 3D printable envelope, with an optical window in Germanium. Two PCBs were developed for assembling the endoscope in two different schemes, to enable frontal or lateral thermal vision setup. The thermal endoscope unit is controlled by a Raspberry external unit. The Infrared Vision Software is provided for controlling the acquisition of thermal frames, and for the thermographic calculation of the object temperature from the input parameters on object surface emissivity and environment. In general, the device enables to perform thermography in applications in which traditional larger equipment cannot be employed, as nondestructive diagnostics in confined space in the engineering field. The thermal endoscope was designed with dimensions also compatible for robotic-assisted/traditional minimally-invasive surgery.

Sliding frictional contact problem of a layer indented by a rigid punch in couple stress elasticity

This paper investigates the frictional contact problem of a layer indented by a rigid punch within the framework of the couple stress elasticity. It is assumed that the layer is homogeneous, isotropic, and fully bonded to a rigid substrate. The mixed-boundary value problem is converted using Fourier transform into a singular integral equation in which the unknown is the contact pressure between the layer and the punch. The integral equation is further derived for the flat and cylindrical punch case profiles, normalized and then solved numerically using the Gauss–Jacobi integration formula. The obtained results are first validated based on those published for the case of a frictionless contact problem of a half-plane indented by a rigid punch and solved within the context of couple stress theory. An extensive parametric study is then conducted to investigate the effect of several parameters on the contact stresses for the both the flat and cylindrical punch profiles. These parameters include the characteristic material length, the layer height, the friction coefficient, the indentation load, and the shear modulus.

A Low-Cost Filament Winding Technology for University Laboratories and Startups.

This paper systematically explains the methodology and results of empirical work on the development of a low-cost filament winding technology for manufacturing axisymmetric polymer composite structures with a high length-to-diameter ratio, such as tubes, motor casings, and pressure vessels. The principal objective was to examine the experiences and most optimal practices in the development of computer-controlled equipment and auxiliary tooling for the wet filament-winding process. To preclude expensive commercial software for the automated control of a winding machine, analytical equations were derived for the winding trajectory of a four-axis filament-winding machine. The feasibility of the proposed equations was successfully validated by laying the fiber along the geodesic path marked on the surface of a cylindrical mandrel with hemispherical ends. Moreover, the carbon/epoxy cylindrical casings with hemispherical ends and port openings of the same diameter were wound to determine the thickness distribution in the hemispherical dome. The fiber volume ratio in the wound composite parts was evaluated using an optical technique.

Deceleration-stage Rayleigh–Taylor growth in a background magnetic field studied in cylindrical and Cartesian geometries

Experiments have identified the Rayleigh–Taylor (RT) instability as one of the greatest obstacles to achieving inertial confinement fusion. Consequently, mitigation strategies to reduce RT growth and fuel–ablator mixing in the hotspot during the deceleration phase of the implosion are of great interest. In this work, the effect of seed magnetic fields on deceleration-phase RT growth are studied in planar and cylindrical geometries under conditions relevant to the National Ignition Facility (NIF) and Omega experiments. The magnetohydrodynamic (MHD) and resistive-MHD capabilities of the FLASH code are used to model imploding cylinders and planar blast-wave-driven targets. Realistic target and laser parameters are presented that suggest the occurrence of morphological differences in late-time RT evolution in the cylindrical NIF case and a measurable difference in spike height of single-mode growth in the planar NIF case. The results of this study indicate the need for target designs to utilize an RT-unstable foam–foam interface in order to achieve sufficient magnetic field amplification to alter RT evolution. Benchmarked FLASH simulations are used to study these magnetic field effects in both resistive and ideal MHD.

Numerical investigation on thermal characteristics of a liquid-cooled lithium-ion battery pack with cylindrical cell casings and a square duct

The thermal management of Lithium-Ion batteries has gained significant attention in the automobile industry. An efficient battery cooling system particularly active cooling techniques have opted as a promising solution in commercial electric vehicles. The physical structure and configuration of the battery pack play a crucial role while designing the battery cooling systems. In the present article, a novel design of a battery pack is designed which includes the cylindrical casings to insert batteries into it and a liquid cooling medium is circulated in its surrounding. This acts as a midway solution between the direct and indirect liquid cooling techniques. The battery cooling system has been numerically modeled using a finite volume approach and theoretically investigated to analyze the thermal behavior of battery systems. The thermal performance of the twenty-five 18,650 Lithium-Ion battery cells arranged in a 5 × 5 configured battery module is evaluated using a forced-liquid cooling system. A detailed thermal analysis has been performed under different discharge rates of 0.5C, 1C, 2C, 3C, 4C, and 5C to determine the impact of heat generation on the battery thermal performance. The numerical model is validated with the empirical correlations of heat transfer for the accuracy of the proposed design. The results reveal that the proposed design minimizes heat accumulation by enhancing the exposure of the cell casings to the heat transfer medium. An even distribution of coolant to each cell provides uniform temperature distribution within the battery module. Further, the effect of natural convection has also been investigated and the results reveal that the maximum temperature rise has been reduced to a great extent at a convective heat transfer coefficient of 25 W/m2 K. Furthermore, an overall battery pack temperature below 28 °C is recorded at 0.5C and even at a higher discharge rate of 5C for 720 s, and the maximum temperature between adjacent cells is limited to 0.12 °C.

Influence of a stopping angle of a spiral coil on the operation of a spiral-screw dispenser

Dosing of dry concentrated feed to dairy cows is one of the most important tasks in the field of livestock mechanization. Devices that carry out volume dosing are more reliable and easier to be manufactured. Volumetric dispensers also include a spiral-screw dispenser – a special case of a screw dispenser. It is proposed to study the working process of the spiral-screw dispenser, namely the influence of a stopping angle of the last turn of the transporting spiral at the end of the discharge hole of the cylindrical casing. The paper indicates the method of determining and the value of the physical and mechanical properties of granulated feed. A laboratory installation on which it is possible to change the angle of installation of the spiral on the drive shaft is described. To study the effect of the stopping angle of the last turn of the transporting spiral on the accuracy of the formation of the feed portion, spirals with a diameter of 49, 73, 97 mm with different steps of 0.75, 1 and 1.25 of the diameter values were used. As a result of the experiments, it was revealed that the lowest coefficient of variation is 0.56 – 17.50%. And, accordingly, the greatest dosing accuracy is obtained when the last turn of the spiral stops at the position of 0°. That is, when the turn stops at the edge of the discharge neck in its lower part and this is typical for all sizes of spirals that were used.

Численное решение задачи о сжатии газа при заданном законе воздействия

Выполнено численное моделирование одномерных течений политропного газа, описывающее сжатие покоящегося газа с плотностью 1 в покоящийся газ, сжатый до значения 10. Описываемое сжатие происходит без ударных волн эффективным с точки зрения энерговложения способом, так как энергия тратится только на сжатие газа, но не на его разгон Controlled thermonuclear fusion (CTF) is an almost unlimited source of energy and scientists have been studying it for several decades. This requires an efficient and stable compression of diyterium-tritium fuel to a very high density. This work addresses shockless one-dimensional (plane, cylindrical and spherical symmetry cases) “compression from rest to rest”, when gas from the initial resting state under the influence of an impenetrable piston is shocklessly transferred to a resting homogeneous state, but compressed by 10000 times. This compression is energetically most advantageous, because work is spent only on the compression, but not on the gas acceleration. Earlier [10] this problem was solved in the opposite direction of time change. In this case, a density jump occurs on the piston which was taken into account in calculations [3] at the final moment of compression. The numerical solution of this problem in the opposite direction of time variation allows calculating the trajectory of the compressing piston in the form of a set of points ( t,r ) at which the gas velocity and density are determined. In this paper, the problem of shockless “compression from rest to rest” is numerically solved in the forward direction of time change if the compressing piston trajectory is known. The compression piston moves along a monotonous trajectory away from the axis or center of symmetry. It is important, when calculating in forward direction of time change, no internal characteristics are initially entered. They, like all gas flow in the calculation area, are determined in the process of direct calculation. This indicates that the trajectory of compressing piston is the recommendation for appropriate physical experiments

The larva of Eubasilissa maclachlani White 1862 (Trichoptera: Phryganeidae) from Thailand, with notes on its biology.

The final-instar larva of Eubasilissa maclachlani White 1862 is described with illustrations for the first time based on Thai specimens. The larva of E. maclachlani exhibits typical morphological characteristics of Phryganeidae. The morphological characteristics of the larva of E. maclachlani can be seen in the following features: First, the band on the frontoclypeus is anchor-like. Second, the ventral apotome is narrowly triangular. Third, the mesonotum is large and membranous, and the mesonotal sa1 sclerites are contiguous mesally. Fourth, comb-like spines, each consisting of tiny points, are distributed over much of the ventromesal surfaces of the fore- and midcoxae. Finally, the shape of tergite IX is heart-like with reddish brown dots. Larvae of E. maclachlani construct cylindrical cases made from many pieces of plant fragments, fastened together by silk in a ring-like pattern, with five successive rings. The larval habitat and phenology are also briefly discussed.

Uniqueness of asymptotically conical tangent flows

Singularities of the mean curvature flow of an embedded surface in R^3 are expected to be modelled on self-shrinkers that are compact, cylindrical, or asymptotically conical. In order to understand the flow before and after the singular time, it is crucial to know the uniqueness of tangent flows at the singularity. In all dimensions, assuming the singularity is multiplicity one, uniqueness in the compact case has been established by the second-named author, and in the cylindrical case by Colding-Minicozzi. We show here the uniqueness of multiplicity-one asymptotically conical tangent flows for mean curvature flow of hypersurfaces. In particular, this implies that when a mean curvature flow has a multiplicity-one conical singularity model, the evolving surface at the singular time has an (isolated) regular conical singularity at the singular point. This should lead to a complete understanding of how to "flow through" such a singularity.

Molten-Salt Battery Response to Open-Circuit and Puncture Testing

Molten-salt thermal batteries may pose hazards in industrial settings if they are damaged or inadvertently ignited. Tests have been performed to determine how a thermal battery would behave without a suitable electrical load, open-circuit, and whether it could be ignited by puncturing the case. Some intact and damaged batteries were ignited by normal means to observe the open-circuit response. None of these batteries ruptured, but some showed evidence of internal short circuits developing. The consequences of puncturing side-fired Ca/CaCrO4 and Li-Si/FeS2 thermal batteries were investigated. Fourteen batteries were punctured on the side of the cylindrical case with a steel rod propelled by a gas gun. The gas gun pressure was modulated to interrogate the probability of battery activation as a function of kinetic energy using the Neyer method. The batteries were observed to activate with kinetic energies in the range of 100–156 J [74–115 ftlb] and velocities between 3.2–4.0 m/s [10–13 ft/s], producing voltages at or below the design value and a normal thermal response. No thermal runaways occurred. The relationships between the kinetic energy and the probability of ignition are presented for both battery chemistries.

Molten-Salt Battery Response to Open-Circuit and Puncture Testing

Molten-salt thermal batteries may pose hazards in industrial settings if they are damaged or inadvertently ignited. Tests have been performed to determine how a thermal battery would behave without a suitable electrical load, open-circuit, and whether it could be ignited by puncturing the case. Some intact and damaged batteries were ignited by normal means to observe the open-circuit response. None of these batteries ruptured, but some showed evidence of internal short circuits developing. The consequences of puncturing side-fired Ca/CaCrO4 and Li-Si/FeS2 thermal batteries were investigated. Fourteen batteries were punctured on the side of the cylindrical case with a steel rod propelled by a gas gun. The gas gun pressure was modulated to interrogate the probability of battery activation as a function of kinetic energy using the Neyer method. The batteries were observed to activate with kinetic energies in the range of 100–156 J [74–115 ftlb] and velocities between 3.2–4.0 m/s [10–13 ft/s], producing voltages at or below the design value and a normal thermal response. No thermal runaways occurred. The relationships between the kinetic energy and the probability of ignition are presented for both battery chemistries.

Superintegrability of separable systems with magnetic field: the cylindrical case

Superintegrability of separable systems with magnetic field: the cylindrical case

Superintegrability of separable systems with magnetic field: the cylindrical case

We present a general method simplifying the search for additional integrals of motion of three dimensional systems with magnetic fields. The method is suitable for systems possessing at least one conserved canonical momentum in a suitable coordinates system. It reduces the problem either to consideration of lower dimensional systems or of particular constrained forms of the hypothetical integral. In particular, it is applicable to all separable systems in the Euclidean space since they are known to possess at least one cyclic coordinates when magnetic field is present. Next, we focus on systems which separate in the cylindrical coordinates. Using our method, we are able to classify all superintegrable systems of this kind under the assumption that all considered integrals are at most second order in the momenta. In addition to already known systems, several new minimally superintegrable systems are found and we show that no quadratically maximally superintegrable ones can exist. We also construct some examples of systems with higher order integrals.

Sloshing of Fluid Between Rotating Inner Vertical Shaft and Stationary Outer Casing

Abstract Unsteady behaviors of free surface around a rotating vertical shaft in cylindrical stationary casing were investigated. Experiments were carried out with various rotating frequency of the shaft at two initial water levels. An axi-symmetrical free surface oscillation took place when the rotational speed of the shaft became larger than a certain value. The frequency of the free surface oscillation decreased as the rotating frequency increased. A theoretical model was developed, and the mechanisms of the free surface oscillation were clarified. The oscillation was found to be a sloshing mode excited by the change of fluid angular velocity, caused by the change of wetted areas on the inner rotating shaft and outer stationary casing, associated with the change in free surface height.

Thermographic Measurement of the Temperature of Reactive Power Compensation Capacitors

An excessive increase in reactive power consumption is unfavorable from the point of view of a power system. For this reason, devices compensating reactive power consumption are used. The capacitor is one such device. Capacitors must be tested regularly during their exploitation. One of the activities that should be performed is testing the degree of heating of the cells of a capacitor bank. Thermography can be used to perform such tests. This non-contact method has its limitations. Due to the angular emissivity and the change in the distance between the lens and the object under observation, the temperature measured with a thermographic camera may differ from the actual temperature. This phenomenon is visible on cylindrical capacitor cases. Consequently, depending on the location of the observation point on the capacitor case, the result of the thermographic temperature measurement may be different. To investigate this phenomenon, experimental work has been undertaken.