Blow Velocity Research Articles

Blood flow and diameter effect in the navigation process of magnetic nanocarriers inside the carotid artery

Background and objective: Serious side effects are occurred during the cancer therapy. Magnetic driving of nanoparticles is a novel method for the elimination of these effects by supplying with anticancer drug or increase the temperature of the infected area. For this reason, a numerical model for optimal guidance of nanoparticles, through the gradient magnetic field, inside the human artery system is presented in this study. Methods: The present method couples Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) techniques. In addition, the optimum magnetic intensity each time is evaluated by using the covariance matrix adaptation evolution strategy (CMA-ES). Under five feature blood flow velocities in cardiac cycle, the developed method evaluate and select the optimum gradient magnetic field in order to eliminate the deviation of the guided nanoparticles from a pre-described trajectory. Results: Results of the simulations indicate both the influence of the blood flow and the volume of nanocarriers in the magnetic driving process in real conditions. Specifically, the blood flow and the volume of particles are inversely proportional parameters in the magnetic navigation process. As the blood flow is decreased, the deviation of nanoparticles compared to the desired path is minimized. On the contrary, the decrease of the volume of nanocarriers increase the distance of particles from the described trajectory. However, greater magnetic gradient values are needed as the blood flow is increased. Furthermore, the imposed gradient magnetic values are strongly connected with the position of the nanoparticles and the blood blow velocity. Conclusions: Based on the results of the present study, the most important parameter in the navigation process is the magnetic volume of particles. Under real conditions, the effect of the blood flow is insignificant compared to the volume of particles in the navigation process. In addition, great differences in the optimized magnetic sequence are presented both among the different blood flows and the volume of particles.

Chemistry of the Gasification of Carbonaceous Raw Material

The paper represents the studies of the process of carbonaceous raw material gasification. The initial material is represented by bituminous coal of grade H with the carbon (C) content of 79.2-85.3 %. Experimental studies have been used to substantiate the parameters of combustible generator gases (СО, Н2, СН4) output depending on the temperature of a reduction zone of the reaction channel and gas flow velocity along its length. It has been identified that the volume of the raw material input to be used for gasification process changes in direct proportion depending on the amount of burnt-out carbon and blow velocity. The gasification is intensified in terms of equal concentration of oxygen and carbon in the reaction channel of an underground gas generator. The gasification rate is stipulated by the intensity of chemical reactions, which depend immediately on the modes of blow mixture supply. Moreover, they depend directly on the intensity of oxygen supply to the coal mass and removal of the gasification products.

Research on low-carbon smelting technology of blast furnace – optimized design of blast furnace

ABSTRACT The optimized blast furnace design is the prerequisite for low-carbon smelting. The salamander depth and bosh angle are the key parameters, which determine the blast furnace longevity. In this paper, the physical and mathematical force model of deadman and cooling stave was established. The relationship between operating parameters and the salamander depth, as well as bosh angle, was analysed, and the gas flow scouring curve was proposed. The following results were obtained: first, the reasonable salamander depth/hearth diameter ratio and bosh angle should be 23∼25% and 73°∼75° in China, respectively. Second, the key factors that influence the floatation of deadman and wear of the cooling stave are the deadman voidage and the slag crust thickness, respectively. Lastly, it is necessary to adjust some measures such as coke ratio, blow velocity and tuyere length. This paper is meant for optimizing the design of blast furnace.

Effect of tapered and semi-tapered geometry on the offshore piles driving performance

Pile driving procedure and efficiency is not only affected by soil parameters, but also by pile geometry including the pile shape and taper angle. Several important effective factors in pile driving are hammer blow counts, penetration and velocity developed in the pile during driving. In this paper, the drivability of different pile geometries was investigated by performing field tests and numerical analyses based on finite difference method. Four steel piles have driven by hammer blows and pile driving analyser (PDA) was used to record the pile dynamic responses. The time histories of the pile head force, settlement, and velocity have been continuously monitored under each hammer blow during the driving tests. The numerical analysis with simulating the soil-pile system in the driving process has been also investigated and compared with the obtained results from the field tests. Parametric studies have been performed on effective parameters on driving such as pile geometry and embedded length. The results indicate that the pile geometry such as tapered and semi-tapered can offer better drivability performance with decreasing cumulative hammer blow counts, increasing the piles' velocity and settlement and the efficiency of the driving operation. These are remarkable in pile driving scenario.

Thermal Imaging and Biometrical Thermography of Humpback Whales

Determining species distributions through time and space remains a primary challenge in cetacean science and conservation. For example, many whales migrate thousands of kilometers every year between remote seasonal habitats along migratory corridors that cross major shipping lanes and intensively harvested fisheries creating a dynamic spatial and temporal context that conservation decisions must take into account. Technological advances enabling automated whale detection have the potential to dramatically improve our knowledge of when and where whales are located, presenting opportunities to help minimize adverse human-whale interactions. Using thermographic data we show that near-horizontal (i.e. high zenith angle) infrared images of humpback whale (Megaptera novaeangliae) blows, dorsal fins, flukes and rostrums record similar magnitude brightness temperature anomalies relative to the adjacent ocean surface. Our results demonstrate that these anomalies are similar in both low latitude and high latitude environments despite a ~16°C difference in ocean surface temperature between study areas. We show that these similarities occur in both environments due to emissivity effects associated with oblique target imaging, rather than differences in cetacean thermoregulation. The consistent and reproducible brightness temperature anomalies we report provide important quantitative constraints that will help facilitate the development of transient temperature anomaly detection algorithms in diverse marine environments. Thermographic videography coupled with laser range finding further enables calculation of whale blow velocity, demonstrating that biometrical measurements are possible for near-horizontal datasets that otherwise suffer from emissivity effects. The thermographic research we present creates a platform for the delivery of 3 important contributions to cetacean conservation: 1) non-invasive species-level identifications based on whale blow shapes and velocities recorded by infrared videography; 2) reduced ship-strike rates through automated thermographic cetacean detection systems deployed in high traffic areas; 3) monitoring the spatial and temporal distributions of endangered animals in remote habitats.

Effects of Gas Blow Velocity on the Surface Properties of Ti-6Al-4V Alloy Treated by Gas Blow IH Nitriding

Effects of Gas Blow Velocity on the Surface Properties of Ti-6Al-4V Alloy Treated by Gas Blow IH Nitriding

ガスブローIH窒化を施したTi-6Al-4V合金の表面特性に及ぼすガス流速の影響

ガスブローIH窒化を施したTi-6Al-4V合金の表面特性に及ぼすガス流速の影響

The effect of a uniform through-surface flow on a cylinder and sphere

The effect of a uniform through-surface flow (velocity$U_{b}$) on a rigid and stationary cylinder and sphere (radius$a$) fixed in a free stream (velocity$U_{\infty }$) is analysed analytically and numerically. The flow is characterised by a dimensionless blow velocity${\it\Lambda}\,(=U_{b}/U_{\infty })$and Reynolds number$Re\,(=2aU_{\infty }/{\it\nu}$, where${\it\nu}$is the kinematic viscosity). High resolution numerical calculations are compared against theoretical predictions over the range$-3\leqslant {\it\Lambda}\leqslant 3$and$Re=1,10,100$for planar flow past a cylinder and axisymmetric flow past a sphere. For$-{\it\Lambda}\gg 1$, the flow is viscously dominated in a thin boundary layer of thickness${\it\nu}/|U_{b}|$adjacent to the rigid surface which develops in a time${\it\nu}/U_{b}^{2}$; the surface vorticity scales as$Re|{\it\Lambda}|U_{\infty }/a$for a cylinder and sphere. A boundary layer analysis is developed to analyse the unsteady viscous forces. Numerical results show that the surface pressure and vorticity distribution within the boundary layer agrees with a steady state analysis. The flow downstream of the body is irrotational so the wake volume flux,$Q_{w}$, is zero and the drag force is$F_{D}=-{\it\rho}U_{\infty }Q_{b}$, where${\it\rho}$is the density of the fluid and$Q_{b}$is the normal flux through the body surface. The drag coefficient is therefore$-2{\rm\pi}{\it\Lambda}$or$-8{\it\Lambda}$for a cylinder or sphere, respectively. A dissipation argument is applied to analyse the drag force; the rate of working of the drag force is balanced by viscous dissipation, flux of stagnation pressure and rate of work by viscous stresses due to sucking. At large$Re|{\it\Lambda}|$, the drag force is largely determined by viscous dissipation for a cylinder, with a weak contribution by the normal viscous stresses, while for a sphere, only$3/4$of the drag force is determined by viscous dissipation with the remaining$1/4$due to the flux of stagnation pressure through the sphere surface. When${\it\Lambda}\gg 1$, the boundary layer thickness initially grows linearly with time as vorticity is blown away from the rigid surface. The vorticity in the boundary layer is weakly dependent on viscous effects and scales as$U_{\infty }/a{\it\Lambda}$or$U_{\infty }/a{\it\Lambda}^{3/2}$for a cylinder and sphere, respectively. For large blow velocity, the vorticity is swept into two well-separated shear layers and the maximum vorticity decreases due to diffusion. The drag force is related to the vorticity distribution on the body surface and an approximate expression can be derived by considering the first term of a Fourier expansion in the surface vorticity. It is found that the drag coefficient$C_{D}$for a cylinder (corrected for flow boundedness) is weakly dependent on${\it\Lambda}$while for a sphere,$C_{D}$decreases with${\it\Lambda}$.

Low-Reynolds-number flow past a cylinder with uniform blowing or sucking

We analyse the low-Reynolds-number flow generated by a cylinder (of radius $a$) in a stream (of velocity $U_{\infty }$) which has a uniform through-surface blowing component (of velocity $U_{b}$). The flow is characterized in terms of the Reynolds number $Re$ ($=2aU_{\infty }/{\it\nu}$, where ${\it\nu}$ is the kinematic viscosity of the fluid) and the dimensionless blow velocity ${\it\Lambda}$ ($=U_{b}/U_{\infty }$). We seek the leading-order symmetric solution of the vorticity field which satisfies the near- and far-field boundary conditions. The drag coefficient is then determined from the vorticity field. For the no-blow case Lamb’s (Phil. Mag., vol. 21, 1911, pp. 112–121) expression is retrieved for $Re\rightarrow 0$. For the strong-sucking case, the asymptotic limit, $C_{D}\approx -2{\rm\pi}{\it\Lambda}$, is confirmed. The blowing solution is valid for ${\it\Lambda}<4/Re$, after which the flow is unsymmetrical about ${\it\theta}={\rm\pi}/2$. The analytical results are compared with full numerical solutions for the drag coefficient $C_{D}$ and the fraction of drag due to viscous stresses. The predictions show good agreement for $Re=0.1$ and ${\it\Lambda}=-5,0,5$.

Experimental Techniques of the Study of the Vortex Disturbances Structure Caused by Point Injection on the Swept Wing Leading Edge

The article contains the results of thermoanemometry on the curvilinear surface and liquid crystal thermography techniques for the investigation of the flow stability on the swept wing leading edge. The numeric results of the velocity disturbance distribution in the boundary layer near the attachment line were received with a help of the thermoanemometry technique. It was found out, that the boundary layer become less stable, when a stationary vortex modifies the flow. The liquid crystal thermography technique allowed to expand the workspace for investigations up to 70 from the attachment line, to receive the visualization pictures of disturbed flow for several regimes of blowing, to reveal an influence of the blow velocity on dimensions and trajectory of stationary disturbances, which were induced by injection. The results of visualizations are in a good agreement with thermoanemometry results

Investigation of the structure of swirling flows in a cyclone chamber under various conditions of gas inlet and outlet

The features of swirling flows in a cyclone chamber of diameter 0.4 m have been investigated experimen- tally for various configurations of inlet nozzles and sizes of the outlet hole. The existence of general laws of swirling flows independent of the inlet and outlet geometry of the chamber, as well as of the air blow velocity has been established. Equations for calculating the main characteristics of the swirling flow in the above chamber have been obtained and their comparison with the dependences established for chambers with other geometric parameters has been made. As analysis of the literature has shown, it is still not clearly understood how the conditions of gas injection into the cyclone chamber and the diameter of its outlet hole influence the character of swirling flows determining such important indices as the separating power of the chamber, its aerodynamic drag, and the inlet blast air distribution over the chamber height. This information is especially topical in creating cyclone-spreader furnaces using the tangential character of air inlet. In this paper, we present the results of the experimental investigation of flows in the cyclone furnace model and their generalization at various configurations, positions, and cross-sectional areas of inlet nozzles in the charac- teristic range of change in the relative diameter of the inlet hole (0.2-0.7). Experimental Setup. In the vertical isothermal cyclone chamber of the experimental setup (10) having an inner diameter D = 0.393 m and a height H = 0.408 m, the top cover with the outlet hole was replaceable. The rela- tive diameter of the outlet hole (d out ⁄ D) was 0.2, 0.3, 0.5, and 0.7. The outlet nozzles with a section of width b n = 15.2 mm had the following configurations and location: 1) the height of the air inlet channel was equal to the cham- ber height: H n = 0.4 m; 2) H n = 0.124 m, the air inlet channel was located in the upper part of the chamber; 3) H n = 0.124 m, the inlet channel was located in the lower part of the chamber; 4) five inlet channels with a total height H n = 0.0248 × 5 = 0.124 m were uniformly distributed over the height of the chamber (Fig. 1). The inlet air velocity was 4.2-13.6 m ⁄ s. The measurement procedure is described in (10). Analysis of the Measurement Data. Flow structure in the cyclone chamber at a height of the air inlet chan- nel H n = 0.4 m. Measurements have shown that the velocity and pressure in the chamber strongly depend on the rela- tive diameter of its outlet hole (Figs. 2-5). However, the profiles of the measured characteristics throughout the range of change in this diameter have qualitatively equal features. They point to the presence of zones of quasi-uniform and

Experimental study on threshold conditions of arcing phenomenon in hot air

In a gas circuit breaker and a molded case circuit breaker, the hot gas between the two metals may transform into the arc plasma. We call this arc formation the “arcing phenomenon”. Since the hot gas somewhat has electrical conductivity, the arcing phenomenon presumably results from a physical mechanism different from that of dielectric breakdown through the cool gas. The present paper describes the transient aspects of the conductance of the hot air that is exposed to the DC voltage and the threshold conditions of the occurrence of the arcing phenomenon. The influence of the velocity of hot air on arcing phenomenon is also discussed. As far as the present experimental condition of 3 mm in gap is concerned, it might be concluded that the threshold voltages for the arcing occurrence in the hot air around 3000 K were 59, 51 and 48 V, for the air blow velocity of 65, 55 and 34 m/s, respectively.

A Study on the Flow of Molten Polymers in a Mold

Filling up flows of several molten polymers in a rectangular cavity grooved on a mold surface were experimentally investigated by means of a flow visualization technique. The conditions for the higher mold printability were obtained as a function of polymer melt temperature, mold wall temperature, air blow pressure and air blow velocity.

Angiographie der A. pudenda und ihrer Äste bei erektiler Dysfunktion

A new simplified technique for evaluating the internal pudendal artery and the penile vessels is described using a new catheter configuration with a very short 90 degrees-angled tip. In 30 consecutive patients, a superselective catheterisation of the internal pudendal artery was achieved in 93%. To improve visualisation of the penile arteries, the selective intraarterial application of 0.2 mg nitroglycerin in addition to the mandatory intracavernous injection of papaverin or prostaglandin E1 has proved to be of value. Examination of the blood blow velocity in the dorsal penile artery with Doppler ultrasound 2 minutes after intra-arterial application of 0.2 mg nitroclyerin showed a mean elevation of the Doppler amplitude by the factor 2.4 (range 0.4-9). With regard to the maximal increase of the blood velocity (range 1-6 minutes), a high interindividual difference was observed.

油圧ブレーカのピストン後室からの油漏れによる性能低下

In order to verify the results of sensitivity analysis based on the analytical model introduced by the authors, an experiment have been carried out by using two different types of the oil hydraulic breakers.The experimental results obtained are summarized as follows.(1) In the case of the forward stroke of the piston, both pressure in the piston rear-chamber and the accumulator are maintained a higher value with decrease the leakage flow rate of the piston rear-chamber.(2) As the leakage flow rate of the piston rear-chamber decreases, the supply oil flow rate also decreases, but the blow velocity of the piston and the number of blow increase. As a consequence, the efficiency of the oil hydraulic breaker is improved sharply.(3) It is confirmed that the results of sensitivity analysis are supported by the experimental results.(4) It is necessary to design and manufacture an oil hydraulic breaker paying particularly close attention to the spaces between the sliding surfaces related to the piston rear-chamber.

油圧ブレーカの性能におよぼす被打撃体の影響

In the design of a hydraulic breaker, it is necessary to take the properties of blowed materials into consideration because the properties have infuluence on the performance of hydraulic breakers. In order to clarify the effect of the materials-properties, an experiment has been organized for evaluating the performance of a breaker. In the experiment, three kinds of hard rubbers have been used for simulating the properties of materials which are broken by breaker.The following results have been obtained.(1) The rate of the energy-absorptive-power for the materials, which is calculated from the blow velocity and the repel velocity of the piston, increases linearly as the supply flow rate and the tate of the supply-flow-energy are increasing.(2) As the rate of energy-absorptive-power is increasing, the blow velocity of the piston increases. but the efficiency of the oil hydraulic breaker decreases.(3) The blow rate increases as the rate of the energy-absorptive- power is increasing. The harder the blowed rubber becomes, the more the blow rate increases. Under the constant supply pressure, the blow rate decreases as the hardness of the blowed rubber is decreasing.

Effect of the Property of Rock on the Dynamic Characteristics of a Pneumatic Rock-Drill

Since a drill must have enough power to crush various rocks, it is necessary for analysis of the dynamic characteristics of a pneumatic rock-drill to consider the physical property of rock under drilling. Thus, the effect of the property of rock the dynamic charactristics of the drill was examined experimentally by using four kinds of rocks. The following results were obtained.(1) Although the blow velocity and the air consumption are not affected by the property of rock, the number of blow is greatly affected and increased with increasing Shore-hardness of rock. This fact indicated that Shore-hardness of rock must considered as a factor affecting the dynamic characteristics of the drill.(2) Considering the fact that the net thermal efficiency increases with increasing performance-index under drilling, it is confirmed that the previous criterion presented by one of the authors can be applied for the design of a pneumatic rock-drill.

The stamp test for rock drillability classification

With the Stamp Test the force and the penetration depth, required for a tungsten carbide button to fracture a rock surface, are determined. The indentation yields a crater in the rock surface, the volume of which is also determined. From the force and the penetration depth one may determine the piston blow velocity and the piston mass/length in a percussive machine, capable of drilling the rock material. The crater volume yields information about the expected drilling rate. Normally rock materials exhibit a decrease in the stamp strength with an increase in the stamp contact area radius. This effect is investigated experimentally for three representative rock materials. In everyday applications the standard Stamp Test radius b = 2 mm is used. Three additional representative rock materials are investigated experimentally and compared with the previous results. The stamp strength of a rock material may be used to define a non-dimensional drilling force F rel , which determines the rock drilling efficiecy. For F rel ⋍ 2 , the maximum drilling rate for constant power of a percussive rock drill is obtained. This is demonstrated in drop hammer experiments, where the rock material, drill bit type, drill bit size and drill bit state of wear are varied, together with the hammer blow velocity.

Experimental Study of Crater Formation in Plastically Deforming Synthetic Rocks

Introduction The resistance of solid materials to indentation or perforation by projectiles or other penetrators has been studied by workers in many areas. Despite these efforts no universally accepted laws or formulas are available for describing experimental observations. In the metals field the force-deformation behavior of impacting bodies is often analyzed by the Hertz law for clastic collisions, the Meyer law if plastic deformations occur, or some combination of both. The similarities of these expressions to empirical drilling formulas of the oil industry are apparent.Beginning with the basic contributions of Simon and co-workers at Battelle, a number of experimental papers concerning the reaction of rocks to vertical impact have appeared in the U. S. mining and petroleum literature. Most published data have, to date, been obtained at atmospheric pressure, although some early high pressure information was reported by Payne and Chippendale. Maurer has recently utilized available brittle impact data to develop a drilling rate equation based on the experimentally observed proportionality between crater volume and blow energy. His result agreed with earlier efforts by both Somerton, who used dimensional analysis, and Outmans, who used plasticity theory.It has long been known that rocks exhibit different modes of failure depending on the state of stress. The literature in this area is considerable; however, papers by Bredthauer, Handin and Hager, and Robinson are adequate to illustrate the point.Since rocks flow plastically at certain triaxial stress conditions, the mathematical theory of plasticity has been used to analyze the rock drilling problem. Cheatham has altered the wedge indentation solution of Prandtl to rocks, and has developed useful equations for penetrator forces under a variety of conditions. Outmans has utilized Hill's solution in a similar manner to develop a drilling rate equation. Both Cheatham and Outmans used the linear Mohr-Coulomb rule to relate rock strength and confining pressure.The actual stress at the hole bottom is not easily ascertained, although photoelastic studies by Galle and Wilhoit, plus the analytical treatment of Cheatham and Wilhoit provide some insight. Consequently it is not clear to what extent the highly idealized rheological model of a perfectly plastic solid can be realistically applied to the rock drilling problem.This paper is the first report on a long range experimental study of crater formation in rocks at elevated stress states. The data presented here are from the first phase of the project. Data obtained from impulsive wedge impacts on two synthetic, plastically deforming rocks are presented. MODEL ROCKS Geologists have long been faced with modelling the behavior of the earth and, as a consequence, have studied scaling problems in some detail. In general, their main problem is handling the wide disparity between laboratory and geologic time. In our studies the time effects (blow velocity or rate of loading, blow duration, etc.) were essentially the same for both model and prototype, as were wedge geometry and tooth penetration. Thus application of available scaling laws suggests that similarity is obtained if the stress-strain curves of model and prototype are similar. JPT P. 1025^