Hydraulic Tube Research Articles

Options for painting hydraulic tubes

Powder coatings offer the most economical solution for coating hydraulic tubes, but several practical issues need to be resolved before going ahead with this strategy. If powders cannot be used then dip application of liquid coatings offers the next most efficient method, but even this option has potential difficulties associated with it, especially if two-component coatings are to be used. If spray application remains the last practical method, then electrostatic spray guns should be preferred to nonelectrostatic applications such as conventional air atomizing or HVLP. In most cases it is unlikely, but not impossible, that any of the spray methods will achieve TEs in the 80 to 90% range as can be achieved by either powder or dip coatings.

Continuous bone distraction with the help of a microhydraulic cylinder

Distraction osteogenesis of the mandible is one treatment option in mandibular hypoplasia. Usually, a non-continuous distraction mode is applied. The aim of the present study was to establish continuous bone distraction using a microhydraulic cylinder. Using a submandibular approach, the mandible was dissected subperiostally on one side in four mini-pigs; corticotomy was performed and the microhydraulic cylinder fixed with two bicortical screws. The hydraulic tube was connected with an automatic hydropneumatic injector system. Following 7 days at rest, a continuous distraction of 1.5 mm per day was performed for 14 days. After 2 and 4 weeks postoperatively, the animals were killed and X-rays taken. The mandible was then removed en bloc and microscopic evaluation of the sections was performed. The microhydraulic cylinder was easy to apply and to handle. The continuous stimulus did induce direct mineralisation of longitudinal oriented collagenous fibre bundles. Bony regeneration seems to be accelerated, which might reduce the postoperatively stabilizing phase.

Role of tapering in aortic wave reflection: hydraulic and mathematical model study

Pressure and flow have been measured simultaneously at six locations along the aorta of an anatomically correct 1 : 1 scale hydraulic elastic tube model of the arterial tree. Our results suggest a discrete reflection point at the level of the renal arteries based on (i) the quarter-wavelength formula and (ii) the comparison of foot-to-foot ( c ff) and apparent phase velocity ( c app). However, separation of the pressure wave into an incident and reflected wave at all six locations indicates continuous reflection: a reflected wave is generated at each location as the forward wave passes by. We did a further analysis using a mathematical transmission line model with a simple tapering geometry (length 50 cm, 31 and 11 mm proximal and distal diameter, respectively) for a low (0.32 ml/mmHg), normal (1.6 ml/mmHg) and high (8 ml/mmHg) value of total arterial compliance. Using the quarter-wavelength formula, a discrete reflection point is found at x=33 cm, the level of the renal arteries, independent of the value of total compliance. However, local analysis comparing c ff and c app does not reveal a marked reflection site, and the analysis of incident and reflected waves merely suggests a continuous reflection. We therefore conclude that the measured in vivo aortic wave reflection indices are the result of at least two interacting phenomena: a continuous wave reflection due to tapering, and local reflections arising from branches at the level of the diaphragm. The continuous reflection is hidden in the input impedance pattern. Using the quarter-wavelength formula or the classical wave separation theory, it appears as a reflection coming from a single discrete site, confusingly also located at the level of the diaphragm. Therefore, the quarter-wavelength formula and the linear wave separation theory should be used with caution to identify wave reflection zones in the presence of tapering, i.e., in most mammalian arteries.

Production of medical radioisotopes in the ORNL high flux isotope reactor (HFIR) for cancer treatment and arterial restenosis therapy after PICA

The High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) represents an important resource for the production of a wide variety of medical radioisotopes. First beginning operation in 1965, the high thermal neutron flux (2.5×1015 neutrons/cm2/sec at 85 MW) and versatile target irradiation and handling facilities provide the opportunity for production of a wide variety of neutron-rich medical radioisotopes of current interest for therapy. In addition to serving as a key production site for californium-252 and other transuranic elements, important examples of therapeutic radioisotopes which are currently routinely produced in the HFIR for distribution include dysprosium-166 (parent of holmium-166), rhenium-186, tin-117m and tungsten-188 (parent of rhenium-188). The nine hydraulic tube (HT) positions in the central high flux region permit the insertion and removal of targets at any time during the operating cycle (22–24 days) and have traditionally represented a major site for production of medical radioisotopes. To increase the irradiation capabilities of the HFIR, special target holders have recently been designed and fabricated which will be installed in the six Peripheral Target Positions (PTP), which are also located in the high flux region. These positions are only accessible during reactor refueling and will be used for long-term irradiations, such as required for the production of tin-117m and tungsten-188. Each of the PTP tubes will be capable of housing a maximum of eight HT targets, thus increasing the total maximum number of HT targets from the current nine, to a total of 57. In this paper the therapeutic use of reactor-produced radioisotopes for bone pain palliation and vascular brachytherapy and the therapeutic medical radioisotope production capabilities of the ORNL HFIR are briefly discussed.

TIMETAL 3-2.5 and TIMETAL 3-2.5 .05Pd

Abstract TIMETAL 3-2.5 (Ti-3%Al-2.5%V) alloy is cold formable and weldable. This alloy is used primarily for honeycomb foil and hydraulic tubing applications. Industrial applications, such as pressure vessels and piping, also utilize this alloy. The alloy is available with palladium stabilization to enhance corrosion resistance. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear and bend strength It also includes information on heat treating. Filing Code: TI-114. Producer or source: Titanium Metals Corporation (Timet).

A Predictive Model for Condensation in Small Hydraulic Diameter Tubes Having Axial Micro-Fins

A semiempirical model is proposed to predict the condensation coefficient inside small hydraulic diameter extruded aluminum tubes having microgrooves. The model accounts for the effects of vapor shear and surface tension forces. Surface tension force is effective in enhancing the condensation coefficient as long as the fin tips are not flooded by condensate. This enhancement increases as mass velocity is reduced. At high mass velocity the flow is vapor shear controlled and the surface tension contribution is very small. The surface tension effect is strongly affected by the fin geometry. A smaller fin tip radius provides a higher surface tension drainage force. A large cross sectional area in the interfin region will allow the surface tension enhancement to occur at lower vapor quality. Separate models are developed for the surface tension and vapor shear controlled regimes and the models are combined in the form of an asymptotic equation. The vapor shear model is based on use of an equivalent mass velocity and the heat-momentum transfer analogy. The surface tension model is analytically based. The model is validated by predicting the authors data for two tube geometries using R-12 and R-134a, and the model predicts 95 percent of the condensation data within ±16 percent.

Evaluation of neutron inelastic scattering for radioisotope production

A systematic study of the production of 117mSn, 119mSn and 195mPt in the hydraulic tube facility (HT) of the ORNL High Flux Isotope Reactor (HFIR) has demonstrated that in all three cases the yields from neutron inelastic scattering ( A Z[n,n′] Am Z) were higher than yields obtained from neutron capture reactions ( ( A−1) Z[n,γ] Am Z) . The corresponding fission-averaged cross-sections were 222 ± 16, 168 ± 12 and 287 ± 20 mb, respectively. The relative gains in the specific activity were 1.4 for 195mPt, 3.3 for 117mSn and 4.4 for 119mSn. The larger gain from 119mSn could be attributed to the relatively lower excitation energy (89.5 keV) of this metastable nucleus. As a part of these studies, the thermal neutron capture cross-sections and resonance integrals for the above reactions and the cross-sections for the [ n,2 n] reactions leading to the above nuclides were also evaluated.

Interdepartmental Interdependence and Coordination: The Case of the Design/Manufacturing Interface

In contrast with the relative stability of interdepartmental coordination mechanisms in ongoing operations, coordination tasks and mechanisms typically change over the course of the product development project’s life cycle. This article presents a taxonomy of these project coordination mechanisms. The taxonomy is based on an inductive analysis of development projects in nine printed circuit board operations and four aircraft hydraulic tubing operations. It distinguishes four modes of interdepartmental interaction—standards, schedules, mutual adaptation and teams (as in Thompson [Thompson, J. D. 1967. Organizations in Action. McGraw-Hill, New York.] and Van de Ven et al. [Van de Ven, A. H., A. L. Delbecq, R. Koenig, Jr. 1976. Determinants of coordination modes within organizations. Amer. Sociological Rev. 41322–338.])—in each of three temporal phases: pre-project, product and process design, and manufacturing. Each of the resulting twelve matrix cells represents a distinct coordination mechanism. Since the objective of coordinating design and manufacturing departments is to ensure an acceptable fit between product design and manufacturing process parameters, the most efficient interdepartmental coordination mechanism is that which is able to deal with the uncertainty of this product/process fit at least cost to the organization. Extending Perrow’s (Perrow, C. 1967. A framework for the comparative analysis of organizations. Amer. Sociological Rev. 32 194–208.) analysis of the two dimensions of uncertainty to the case of product/process fit, the choice of interaction mode within each project phase is hypothesized to depend on the novelty of the product/process fit problem, and the relative importance of coordination effort across the three project phases is hypothesized to depend on the analyzability of the product/process fit problem.

Kopplung einer einfachen sub- oder superkritischen Extraktion mit normalen Analysenmethoden

Substances can be extracted in pressure resistant hydraulic tubes with carbon dioxide, ammonia, or other compressed solvents and the extracts can be analyzed by conventional methods. The elevated pressure is indicated by a small gauge and after extraction reduced to normal pressure by a small capillary, which can be connected to the bulk volume of a syringe in order to collect the extract in this syringe. The extract is then transferred into an analytical apparatus, e.g. a gaschromatograph. The method is demonstrated by the gas chromatogram of clove oil from different preparation methods.

Developments of the Belarussian Republic scientific and production union for powder metallurgy in the area of new materials and methods and their use in machine building

Today the Republic of Belarus is emerging as a region of skilled machine building, of developed chemical, petrochemical, light, and food industries, and electronics. Traditional products of the specialization of its industry are wheeled tractors, trucks, metal cutting tools, automatic lines, wrist-watches, motorcycles, television sets, computers, household refrigerators, bicycles, bearings, and electrical equipment. This determines the directions of scientific investigations in the area of powder metallurgy including the development of new materials and effective methods of production from them of parts of mechanisms, machines, equipment, etc. The start of development of powder metallurgy in the republic was the creation in 1957 of a special laboratory in the Department of Metals Technology of the Belorussian Polytechnic Institute. In 1980 there was formed the Belorussian Republic Scientific and Production Union for Powder Metallurgy, which included the Scientific-Research and Design Technology Institute for Powder Metallurgy (the head organization) and Molodechno Powder Metallurgy Plant. The path of development of power metallurgy in the republic was long and complex. For example, while in 1960 there were two areas in Belorussia with a total volume of production of about 20 tons of parts, in 1990 14 areas, shops, and a plant with a total volume of production of 8500 tons had been placed in service. In the territory of the republic alone more than 50 areas for the application of coatings have been created in recent years with the direct participation of the union. Today the primary directions in the activity of the union are development of the theoretical fundamentals of use of pulsed loads for creation of powder and composite materials with increase physicomechanical and functional properties, the development of new powder and composite materials and progressive methods of production from them of parts for machine building and other branches of technology with use of methods of static pressing, hot and cold forming, and sintering of freely poured powder, development of the theoretical fundamentals of application of protective coatings on machine and tool parts, and the development of equipment for accomplishment of them. As the result of training of engineering and scientific personnel in the Belorussian Polytechnic Institute (now the Polytechnic Academy) a well operating chain of scientific research-design and technology development-experimental production-industrial production-training of personnel has been established. In the union a broad range of materials which have found use in the machine building, radio and electronics, and electrical industries has been developed. To satisfy the requirements of industry Molodechno Powder Metallurgy Plant has started production of new forms of highly effective production such as blanks for electrical machinery commutators, gear hydraulic pump parts, friction parts, thermal tubes, and filters. New tribotechnical and constructional materials, coatings resistant to wear and corrosion, and porous materials are being developed. High-Density Constructional Materials and Parts of Powder Metallurgy Ferrous and Nonferrous Metals Produced with Use of Plastic Deformation of the Sintered Blanks. One of the effective methods of increasing the physicomechanical properties of ferrous and nonferrous metal-base powder metallurgy materials is plastic deformation of sintered powder metallurgy blanks in the cold condition and with heating. The essence of these processes is plastic flow of the sintered material under the action on it of external loads at normal or increased temperatures. This provides production of parts of the required

Pressure Control in Hydraulic Tube Forming

At THD/PtU a manufacturing technique was developed in order to form tubes under internal hydraulic pressure and axial farce. The forming of the bulging tube can be influenced by pressure control. Algorithms can be developed to define pressure depending on the axial force or parameters to that, such as displacement and time. The most important parameters of geometry and load are recorded during the process.

LDV measurements of orifice jet flows at low Reynolds numbers.

Measurements of orifice jet flows in oil hydraulic tubes with LDV were carried out in order to clarify the flow structure which causes the peculiar behavior in the pressure recovery previously discovered by some of the present authors. The findings are as follows: with Re around 200, the orifice jet flow starts to become turbulent, exhibiting observable pressure recovery. In a typical turbulent jet flow of a low Reynolds number the axial velocity rapidly decreases downstream, and then gradually increases until it reaches the velocity of the corresponding Poiseuille laminar flow. In this rapid deceleration field, a small percentage of the kinetic energy of the main flow is restored to the static pressure, while most of it is consumed to develop turbulence which becomes most intense at the end of the field. The deceleration field travels noticeably downstream as Re decreases below 1000, which coincides with the movement of the pressure recovering region.

Effect of crystallographic texture on flexure fatigue properties of Ti3Al2.5V hydraulic tubing: Meredith, S.E. and Schemel, J.H. ASTM J. Test. Eval. Mar. 1990 18, (2), 98–105

Effect of crystallographic texture on flexure fatigue properties of Ti3Al2.5V hydraulic tubing: Meredith, S.E. and Schemel, J.H. ASTM J. Test. Eval. Mar. 1990 18, (2), 98–105

Navier-Stokes Flow Analysis for Hydraulic Turbine Draft Tubes

Three-dimensional turbulent viscous flow analyses for hydraulic turbine elbow draft tubes are performed by solving Reynolds averaged Navier-Stokes equations closed with a two-equation turbulence model. The predicted pressure recovery factor and flow behavior in the draft tube with a wide range of swirling flows at the inlet agree well with experimental data. During the validation of the Navier-Stokes flow analysis, particular attention was paid to the effect of grid size on the accuracy of the numerical result and the importance of accurately specifying the inlet flow condition.

The hydraulic tube bulging of a tube-attached lining rubber membrane with axial compressive force.

The authors have developed a new machine for tube bulging which initially puts a deflated rubber membrane into a work tube and drives the internal pressure through a membrane after the initial settingup. Using this new machine, the effects of the tube end condition and tube length on the deformed shaped and the strain distribution are examined experimentally. Three cases of the tube end conditions, (A) axially fixed, (B) axially free and (C) axially compressed by force, are parametrically investigated. The results are as follows: (1) comparing at the same bulge height, the internal pressure is lower with the longer tube and also lower with the end condition changing from case A to C, (2) when the tube is short and/or the axial compressive force is small, the deformed shape appears as a barrel, and when the tube is long and/or the axial force is large, it has a cylindrical region uniformly expanded at its center, and (3) the axial compressive force tends to prevent thickness reduction of the tube.

CAD/CAM: managerial challenges and research issues

Results are reported of an exploratory investigation into the managerial problems of integrating computer-aided design (broadly construed to include engineering design and drafting), and computer-aided manufacturing (encompassing machine control, materials handling, manufacturing scheduling, planning and administration, testing and quality assurance). The focus is on engineering, design, fabrication, assembly, and test of printed circuit boards used in the electronics industry and on design and fabrication of hydraulic tubing in the aircraft industry. Nine US electronics businesses and four US aircraft companies were visited with the aim of synthesizing the elements of 'best practice'. Managerial problems and research issues are identified at each of five key levels of organizational learning: skills, procedures, structure, strategy, and culture. >

Comparison of human jejunal and ileal fat absorption by electron microscopy

Morphologic and physiologic experiments in rodents have demonstrated differences between jejunal and ileal fat absorption. Compared with the rat jejunum, absorbed lipid particles within rat ileal absorptive cells are larger and exit at a slower rate. To evaluate the relevance of these observations to humans, we studied jejunal and ileal ultrastructure in 3 volunteers, each of whom had an intact small intestine and an ileostomy postcolectomy for ulcerative colitis. Proximal jejunal biopsy specimens were obtained via a hydraulic tube after an overnight fast and again after a 20-min intrajejunal lipid infusion. On a separate day, terminal ileal biopsy specimens were taken via the stoma with a small steerable suction biopsy tube after an overnight fast and again after a 20-min intraileal infusion of the same lipid mixture. One volunteer underwent biopsy after a 60-min ileal infusion of a digested meal of higher lipid content. Electron microscopy of fasting human jejunal absorptive cells revealed obvious smooth endoplasmic reticulum in the extreme apical region beneath the terminal web; very low density lipoprotein particles were observed within smooth endoplasmic reticulum and Golgi cisternae. In contrast, fasting human ileal absorptive cells contained less apical smooth endoplasmic reticulum and fewer or no very low density lipoprotein particles. After the 20-min infusion of lower-lipid content, human jejunal and ileal absorptive cells were indistinguishable because they contained fat particles of the same size and number within smooth endoplasmic reticulum, Golgi cisternae, and extracellular spaces. After the 60-min ileal infusion of higher-lipid content, human ileal absorptive cells appeared to be the same as those of the human jejunum after similar lipid infusions. Our observations of the ultrastructural similarity in human jejunal and ileal absorptive cells after lipid infusions contrasts with those in rodents and may reflect species-specific differences in mechanisms of fat absorption.

Apparatus for Extraction of Undisturbed Samples on Noncohesive Subsoils

AbstractA sampler was designed and tested for extracting 60‐ by 53‐mm (length by depth) undisturbed core samples from subsoils. The sampler consists of a sample cylinder “barrel,” and an “adaptor block” for fitting the barrel to the end of a 76.1‐mm o.d. hydraulic probe tube. Samples are taken by augering to the desired depth, and using the tube and sampler assembly to extract the sample. The tube and sampler assembly can also be used with a protective steel anvil to remove samples in shallow subsoils without a hydraulic probe. Samples on sands have been taken as deep as 2.5 m using the hydraulic probe, and as deep as 0.61 m using the anvil and maul method.

Three‐dimensional analysis of the flow in a curved hydraulic turbine draft tube

AbstractThe three‐dimensional turbulent flow in a curved hydraulic turbine draft tube is studied numerically. The analysis is based on the steady Reynolds‐averaged Navier–Stokes equations closed with the κ‐ε model. The governing equations are discretized by a conservative finite volume formulation on a non‐orthogonal body‐fitted co‐ordinate system. Two grid systems, one with 34 × 16 × 12 nodes and another with 50 × 30 × 22 nodes, have been used and the results from them are compared. In terms of computing effort, the number of iterations needed to yield the same degree of convergence is found to be proportional to the square root of the total number of nodes employed, which is consistent with an earlier study made for two‐dimensional flows using the same algorithm. Calculations have been performed over a wide range of inlet swirl, using both the hybrid and second‐order upwind schemes on coarse and fine grids. The addition of inlet swirl is found to eliminate the stalling characteristics in the downstream region and modify the behaviour of the flow markedly in the elbow region, thereby affecting the overall pressure recovery noticeably. The recovery factor increases up to a swirl ratio of about 0˙75, and then drops off. Although the general trends obtained with both finite difference operators are in agreement, the quantitative values as well as some of the fine flow structures can differ. Many of the detailed features observed on the fine grid system are smeared out on the coarse grid system, pointing out the necessity of both a good finite difference operator and a good grid distribution for an accurate result.

Burn-up cross sections of 51Cr, 59Fe, 65Zn, 86Rb, 103Ru

Abstract Targets of Cr, Fe, Zn, Rb, and Ru were irradiated in the hydraulic tube of the Oak Ridge HFIR reactor at a neutron flux of 2.6 × 1015 n/cm2sec for 1 day and 20 days. The reactor burn-up cross sections (in barns) of the radioactive product nuclides are: 51Cr, <10; 59Fe, <10; 65Zn, 60±30; 86Rb, <20; 103Ru, <20.