Probabilistic pipe fracture evaluations for leak-rate-detection applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, S.; Ghadiali, N.; Paul, D.

1995-04-01

Regulatory Guide 1.45, {open_quotes}Reactor Coolant Pressure Boundary Leakage Detection Systems,{close_quotes} was published by the U.S. Nuclear Regulatory Commission (NRC) in May 1973, and provides guidance on leak detection methods and system requirements for Light Water Reactors. Additionally, leak detection limits are specified in plant Technical Specifications and are different for Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). These leak detection limits are also used in leak-before-break evaluations performed in accordance with Draft Standard Review Plan, Section 3.6.3, {open_quotes}Leak Before Break Evaluation Procedures{close_quotes} where a margin of 10 on the leak detection limit is used in determining the crackmore » size considered in subsequent fracture analyses. This study was requested by the NRC to: (1) evaluate the conditional failure probability for BWR and PWR piping for pipes that were leaking at the allowable leak detection limit, and (2) evaluate the margin of 10 to determine if it was unnecessarily large. A probabilistic approach was undertaken to conduct fracture evaluations of circumferentially cracked pipes for leak-rate-detection applications. Sixteen nuclear piping systems in BWR and PWR plants were analyzed to evaluate conditional failure probability and effects of crack-morphology variability on the current margins used in leak rate detection for leak-before-break.« less

Impact of Casing Expansion on the Mechanical and Petro-Physical Properties of Wellbore Cements

NASA Astrophysics Data System (ADS)

Oyibo, A. E.

2014-12-01

The main objective of this research is to investigate the applicability of expandable casing technology as a remediation technique for leaky wells resulting in gas migration problems. Micro annulus is usually created at the cement-formation/cement-casing interface or within the cement matrix either due to poor primary cementing or as a result of activities such as temperature and pressure variation or fracturing operations. Recent reports on gas migration in hydraulically fractured wellbores, has raised concerns on the contamination of fresh water aquifers resulting from fluid migration though this flow path. A unique bench-scale physical model which utilizes expandable tubulars in the remediation of micro annular gas flow has been used to simulate expansion of a previously-cemented casing under field-like conditions. Three different designs of cement slurry: regular 16.4 lb. /gal, 16.4 lb. /gal base slurry foamed to 13 lb. /gal and 16.4 lb. /gal cement slurry with 10% salt concentration. Gas flow path (microannulus) was artificially created at the pipe-cement interface by rotating the inner pipe in a pipe inside pipe assembly with cement in the annulus within the first few hours of hydration to create debonding at the cement-casing interface. Nitrogen gas flow-through experiments were performed before and after the expansion to confirm the sealing of the microannulus. The results obtained confirmed the effectiveness of this technique in the complete closure of gas leakage path, providing seal-tight cement-formation interface free of microannulus. The manipulation of the cement sheath during the casing expansion resulted in improved porosity, permeability and the strength of the cement sheath. SEM micrographs revealed decrease in pore size and fracturing of unhydrated cement grains within the cement matrix. This technology has great potential to become one of the leading cement remediation techniques for leaks behind the casing if implemented. Keywords: Wellbore Integrity, Casing Expansion, Well Gas Leaks, CSH, Pore Collapse, Cement Pore Water.

The structural significance of HAZ sigma phase formation in welded 25%Cr super duplex pipework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiesner, C.S.; Garwood, S.J.; Bowden, P.L.

1993-12-31

The welding of 25%Cr duplex stainless steel can lead to the formation of sigma phase in both weld metal and heat affected zone (HAZ) regions. It has generally been accepted that this can be avoided by the adoption of appropriate welding procedure controls, generally aimed at reducing heat input and promoting rapid cooling rates. However, experience during pipe spool fabrication for the Marathon East Brae Project has shown that it is extremely difficult to satisfy a welding specification requiring sigma free HAZs. This has proved a particular problem with thin wall pipe welds made in the 2G/5G or 6G fixedmore » positions, where the joint geometry reduces heat flow away from the weld and welding conditions tend to result in the use of higher heat inputs. This paper examines the effect of sigma phase on the fracture toughness of 25%Cr super duplex steel (UNS S32760). It is shown that the CTOD toughness at {minus}20 C decreases as soon as any sigma phase is present and continues to decrease with increasing sigma levels. The toughness of the sigmatized specimens produced by heat treatment was shown to be conservative compared to the toughness measured in the HAZ of 14.2mm and 7.1mm thick pipe weldments, made with welding parameters chosen to enhance HAZ sigma phase formation. Based on the CTOD versus percent sigma level relationship derived from the laboratory specimens, fracture assessment calculations of tolerable flaw sizes were performed. These demonstrated that under the severest design conditions, assuming the maximum flaw sizes which could remain undetected in the pipework, sigma levels up to 2.5% can be tolerated safely. The conservatism of the fracture assessments for predicting the performance of weldments was demonstrated by full scale tensile testing of 2 inch nominal bore x 2.77 mm wall thickness pipe butt welds containing through-thickness circumferential fatigue cracks located in the sigmatized HAZ.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozluk, M.J.; Vijay, D.K.

Postulated catastrophic rupture of high-energy piping systems is the fundamental criterion used for the safety design basis of both light and heavy water nuclear generating stations. Historically, the criterion has been applied by assuming a nonmechanistic instantaneous double-ended guillotine rupture of the largest diameter pipes inside of containment. Nonmechanistic, meaning that the assumption of an instantaneous guillotine rupture has not been based on stresses in the pipe, failure mechanisms, toughness of the piping material, nor the dynamics of the ruptured pipe ends as they separate. This postulated instantaneous double-ended guillotine rupture of a pipe was a convenient simplifying assumption thatmore » resulted in a conservative accident scenario. This conservative accident scenario has now become entrenched as the design basis accident for: containment design, shutdown system design, emergency fuel cooling systems design, and to establish environmental qualification temperature and pressure conditions. The requirement to address dynamic effects associated with the postulated pipe rupture subsequently evolved. The dynamic effects include: potential missiles, pipe whipping, blowdown jets, and thermal-hydraulic transients. Recent advances in fracture mechanics research have demonstrated that certain pipes under specific conditions cannot crack in ways that result in an instantaneous guillotine rupture. Canadian utilities are now using mechanistic fracture mechanics and leak-before-break assessments on a case-by-case basis, in limited applications, to support licensing cases which seek exemption from the need to consider the various dynamic effects associated with postulated instantaneous catastrophic rupture of high-energy piping systems inside and outside of containment.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brochard, J.; Charras, T.; Ghoudi, M.

Modifications to a computer code for ductile fracture assessment of piping systems with postulated circumferential through-wall cracks under static or dynamic loading are very briefly described. The modifications extend the capabilities of the CASTEM2000 code to the determination of fracture parameters under creep conditions. The main advantage of the approach is that thermal loads can be evaluated as secondary stresses. The code is applicable to piping systems for which crack propagation predictions differ significantly depending on whether thermal stresses are considered as primary or secondary stresses.

Low-frequency fluid waves in fractures and pipes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korneev, Valeri

2010-09-01

Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importancemore » of including these wave effects into poroelastic theories.« less

State-of-the-art report on piping fracture mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkowski, G.M.; Olson, R.J.; Scott, P.M.

1998-01-01

This report is an in-depth summary of the state-of-the-art in nuclear piping fracture mechanics. It represents the culmination of 20 years of work done primarily in the US, but also attempts to include important aspects from other international efforts. Although the focus of this work was for the nuclear industry, the technology is also applicable in many cases to fossil plants, petrochemical/refinery plants, and the oil and gas industry. In compiling this detailed summary report, all of the equations and details of the analysis procedure or experimental results are not necessarily included. Rather, the report describes the important aspects andmore » limitations, tells the reader where he can go for further information, and more importantly, describes the accuracy of the models. Nevertheless, the report still contains over 150 equations and over 400 references. The main sections of this report describe: (1) the evolution of piping fracture mechanics history relative to the developments of the nuclear industry, (2) technical developments in stress analyses, material property aspects, and fracture mechanics analyses, (3) unresolved issues and technically evolving areas, and (4) a summary of conclusions of major developments to date.« less

J-R fracture characteristics of ferritic steels for RPVs and RCS piping of nuclear power plants

NASA Astrophysics Data System (ADS)

Yoon, Ji-Hyun; Lee, Bong-Sang; Hong, Jun-Hwa

2001-10-01

J-R fracture resistance tests have been performed on 3 heats of SA508-Gr.3 nuclear reactor pressure vessel (RPV) steel as well as 2 heats of SA516-Gr.70 and a heat of SA508-Gr.1a steels for nuclear reactor coolant system (RCS) piping. For the latter two steels, dynamic in addition to static J-R fracture resistances were investigated. From the test results of the SA508-Gr.3 steels, the J-R fracture resistance was superior in the following order: Si-killing steel, modified VCD steel and VCD steel. Microstructural analyses were carried out to correlate J-R fracture resistances with microstructural characteristics. According to the test results for SA508-Gr.1a and SA516-Gr.70 steels, all of the tested steels showed steep drops in fracture resistance at certain temperature and loading rate combinations. One heat of SA516-Gr.70 steel was very sensitive to dynamic strain aging and its fracture resistance was significantly low. It was concluded that microstructural and chemical factors affect the J-R fracture and DSA characteristics of SA516-Gr.70 steels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chattopadhyay, J.; Dutta, B.K.; Kushwaha, H.S.

Leak-Before-Break (LBB) is being used to design the primary heat transport piping system of 500 MWe Indian Pressurized Heavy Water Reactors (IPHWR). The work is categorized in three directions to demonstrate three levels of safety against sudden catastrophic break. Level 1 is inherent in the design procedure of piping system as per ASME Sec.III with a well defined factor of safety. Level 2 consists of fatigue crack growth study of a postulated part-through flaw at the inside surface of pipes. Level 3 is stability analysis of a postulated leakage size flaw under the maximum credible loading condition. Developmental work relatedmore » to demonstration of level 2 and level 3 confidence is described in this paper. In a case study on fatigue crack growth on PHT straight pipes for level 2, negligible crack growth is predicted for the life of the reactor. For level 3 analysis, the R6 method has been adopted. A database to evaluate SIF of elbows with throughwall flaws under combined internal pressure and bending moment has been generated to provide one of the inputs for R6 method. The methodology of safety assessment of elbow using R6 method has been demonstrated for a typical pump discharge elbow. In this analysis, limit load of the cracked elbow has been determined by carrying out elasto-plastic finite element analysis. The limit load results compared well with those given by Miller. However, it requires further study to give a general form of limit load solution. On the experimental front, a set of small diameter pipe fracture experiments have been carried out at room temperature and 300{degrees}C. Two important observations of the experiments are - appreciable drop in maximum load at 300{degrees}C in case of SS pipes and out-of-plane crack growth in case of CS pipes. Experimental load deflection curves are finally compared with five J-estimation schemes predictions. A material database of PHT piping materials is also being generated for use in LBB analysis.« less

ADVANCED INTEGRATION OF MULTI-SCALE MECHANICS AND WELDING PROCESS SIMULATION IN WELD INTEGRITY ASSESSMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkowski, Gery M.; Rudland, David L.; Shim, Do-Jun

2008-06-30

The potential to save trillions of BTU’s in energy usage and billions of dollars in cost on an annual basis based on use of higher strength steel in major oil and gas transmission pipeline construction is a compelling opportunity recognized by both the US Department of Energy (DOE). The use of high-strength steels (X100) is expected to result in energy savings across the spectrum, from manufacturing the pipe to transportation and fabrication, including welding of line pipe. Elementary examples of energy savings include more the 25 trillion BTUs saved annually based on lower energy costs to produce the thinner-walled high-strengthmore » steel pipe, with the potential for the US part of the Alaskan pipeline alone saving more than 7 trillion BTU in production and much more in transportation and assembling. Annual production, maintenance and installation of just US domestic transmission pipeline is likely to save 5 to 10 times this amount based on current planned and anticipated expansions of oil and gas lines in North America. Among the most important conclusions from these studies were: • While computational weld models to predict residual stress and distortions are well-established and accurate, related microstructure models need improvement. • Fracture Initiation Transition Temperature (FITT) Master Curve properly predicts surface-cracked pipe brittle-to-ductile initiation temperature. It has value in developing Codes and Standards to better correlate full-scale behavior from either CTOD or Charpy test results with the proper temperature shifts from the FITT master curve method. • For stress-based flaw evaluation criteria, the new circumferentially cracked pipe limit-load solution in the 2007 API 1104 Appendix A approach is overly conservative by a factor of 4/π, which has additional implications. . • For strain-based design of girth weld defects, the hoop stress effect is the most significant parameter impacting CTOD-driving force and can increase the crack-driving force by a factor of 2 depending on strain-hardening, pressure level as a % of SMYS, and flaw size. • From years of experience in circumferential fracture analyses and experimentation, there has not been sufficient integration of work performed for other industries into analogous problems facing the oil and gas pipeline markets. Some very basic concepts and problems solved previously in these fields could have circumvented inconsistencies seen in the stress-based and strain-based analysis efforts. For example, in nuclear utility piping work, more detailed elastic-plastic fracture analyses were always validated in their ability to predict loads and displacements (stresses and strains). The eventual implementation of these methodologies will result in acceleration of the industry adoption of higher-strength line-pipe steels.« less

Microstructure-dependent fracture toughness (JIC) variations in dissimilar pipe welds for pressure vessel system of nuclear plants

NASA Astrophysics Data System (ADS)

Rathod, Dinesh W.; Pandey, Sunil; Singh, P. K.; Kumar, Suranjit

2017-09-01

In present study, dissimilar metal weld (DMW) joints between SA508Gr.3cl.1 ferritic steel and SS304LN pipes were prepared using Inconel 82/182, and Inconel 52/152 consumables. Metallurgical properties and their influence on fracture toughness of weldment regions and interfacial regions could play a significant role in integrity assessment of these joints. Ni-based consumables exhibit complex metallurgical properties at interfacial regions. The metallurgical characterization and fracture toughness studies of Inconel 82/182 and Inconel 52/152 joints have been carried out for determining the optimum consumable for DMW joint requirements and the effect of microstructure on fracture toughness in weldment regions. The present codes and procedures for integrity assessment of DMW joints have not given due considerations of metallurgical properties. The requirements for metallurgical properties by considering their effect on fracture toughness properties in integrity assessment have been discussed for reliable analysis. Inconel 82/182 is preferred over Inconel 52/152 joints owing to favorable metallurgical and fracture toughness properties across the interfacial and weldment regions.

Microstructural characterization of pipe bomb fragments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregory, Otto, E-mail: gregory@egr.uri.edu; Oxley, Jimmie; Smith, James

2010-03-15

Recovered pipe bomb fragments, exploded under controlled conditions, have been characterized using scanning electron microscopy, optical microscopy and microhardness. Specifically, this paper examines the microstructural changes in plain carbon-steel fragments collected after the controlled explosion of galvanized, schedule 40, continuously welded, steel pipes filled with various smokeless powders. A number of microstructural changes were observed in the recovered pipe fragments: deformation of the soft alpha-ferrite grains, deformation of pearlite colonies, twin formation, bands of distorted pearlite colonies, slip bands, and cross-slip bands. These microstructural changes were correlated with the relative energy of the smokeless powder fillers. The energy of themore » smokeless powder was reflected in a reduction in thickness of the pipe fragments (due to plastic strain prior to fracture) and an increase in microhardness. Moreover, within fragments from a single pipe, there was a radial variation in microhardness, with the microhardness at the outer wall being greater than that at the inner wall. These findings were consistent with the premise that, with the high energy fillers, extensive plastic deformation and wall thinning occurred prior to pipe fracture. Ultimately, the information collected from this investigation will be used to develop a database, where the fragment microstructure and microhardness will be correlated with type of explosive filler and bomb design. Some analyses, specifically wall thinning and microhardness, may aid in field characterization of explosive devices.« less

Flexible mobile robot system for smart optical pipe inspection

NASA Astrophysics Data System (ADS)

Kampfer, Wolfram; Bartzke, Ralf; Ziehl, Wolfgang

1998-03-01

Damages of pipes can be inspected and graded by TV technology available on the market. Remotely controlled vehicles carry a TV-camera through pipes. Thus, depending on the experience and the capability of the operator, diagnosis failures can not be avoided. The classification of damages requires the knowledge of the exact geometrical dimensions of the damages such as width and depth of cracks, fractures and defect connections. Within the framework of a joint R&D project a sensor based pipe inspection system named RODIAS has been developed with two partners from industry and research institute. It consists of a remotely controlled mobile robot which carries intelligent sensors for on-line sewerage inspection purpose. The sensor is based on a 3D-optical sensor and a laser distance sensor. The laser distance sensor is integrated in the optical system of the camera and can measure the distance between camera and object. The angle of view can be determined from the position of the pan and tilt unit. With coordinate transformations it is possible to calculate the spatial coordinates for every point of the video image. So the geometry of an object can be described exactly. The company Optimess has developed TriScan32, a special software for pipe condition classification. The user can start complex measurements of profiles, pipe displacements or crack widths simply by pressing a push-button. The measuring results are stored together with other data like verbal damage descriptions and digitized images in a data base.

Evaluation of fatigue crack behavior in electron beam irradiated polyethylene pipes

NASA Astrophysics Data System (ADS)

Pokharel, Pashupati; Jian, Wei; Choi, Sunwoong

2016-09-01

A cracked round bar (CRB) fatigue test was employed to determine the slow crack growth (SCG) behavior of samples from high density polyethylene (HDPE) pipes using PE4710 resin. The structure property relationships of fatigue failure of polyethylene CRB specimens which have undergone various degree of electron beam (EB) irradiation were investigated by observing fatigue failure strength and the corresponding fracture surface morphology. Tensile test of these HDPE specimens showed improvements in modulus and yield strength while the failure strain decreased with increasing EB irradiation. The CRB fatigue test of HDPE pipe showed remarkable effect of EB irradiation on number of cycles to failure. The slopes of the stress-cycles to failure curve were similar for 0-100 kGy; however, significantly higher slope was observed for 500 kGy EB irradiated pipe. Also, the cycle to fatigue failure was seen to decrease as with EB irradiation in the high stress range, ∆σ=(16 MPa to 10.8 MPa); however, 500 kGy EB irradiated samples showed longer cycles to failure than the un-irradiated specimens at the stress range below 9.9 MPa and the corresponding initial stress intensity factor (∆KI,0)=0.712 MPa m1/2. The fracture surface morphology indicated that the cross-linked network in 500 kGy EB irradiated PE pipe can endure low dynamic load more effectively than the parent pipe.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program: The Effects of Vegetation on these Structural Integrity of Sandy Levees.

DTIC Science & Technology

1991-08-01

cracking in earth dams commonly occurs by hydraulic fracturing . Hydraulic fracturing is a tensile separation along an internal surface in a 25 soil mass...stress. This hydraulic fracturing is facilitated by differential settle- ment and internal stress transfer in an earthen structure. Sherard also showed...the hydraulic fracturing . 42. BioLic activity, i.e., the actions of plant roots and burrowing animals, has provided a popular explanation for pipe

Influence of structure on static cracking resistance and fracture of welded joints of pipe steels of strength class K60

NASA Astrophysics Data System (ADS)

Tereshchenko, N. A.; Tabatchikova, T. I.; Yakovleva, I. L.; Makovetskii, A. N.; Shander, S. V.

2017-07-01

The static cracking resistance of a number of welded joints made from pipe steels of K60 strength class has been determined. It has been established that the deformation parameter CTOD varies significantly at identical parameters of weldability of steels. The character of fracture has been investigated and the zone of local brittleness of welded joints has been studied. It has been shown that the ability of a metal to resist cracking is determined by the austenite grain size and by the bainite morphology in the region of overheating in the heat-affected zone of a welded joint.

Effect of Combined Loading Due to Bending and Internal Pressure on Pipe Flaw Evaluation Criteria

NASA Astrophysics Data System (ADS)

Miura, Naoki; Sakai, Shinsuke

Considering a rule for the rationalization of maintenance of Light Water Reactor piping, reliable flaw evaluation criteria are essential for determining how a detected flaw will be detrimental to continuous plant operation. Ductile fracture is one of the dominant failure modes that must be considered for carbon steel piping and can be analyzed by elastic-plastic fracture mechanics. Some analytical efforts have provided various flaw evaluation criteria using load correction factors, such as the Z-factors in the JSME codes on fitness-for-service for nuclear power plants and the section XI of the ASME boiler and pressure vessel code. The present Z-factors were conventionally determined, taking conservativity and simplicity into account; however, the effect of internal pressure, which is an important factor under actual plant conditions, was not adequately considered. Recently, a J-estimation scheme, LBB.ENGC for the ductile fracture analysis of circumferentially through-wall-cracked pipes subjected to combined loading was developed for more accurate prediction under more realistic conditions. This method explicitly incorporates the contributions of both bending and tension due to internal pressure by means of a scheme that is compatible with an arbitrary combined-loading history. In this study, the effect of internal pressure on the flaw evaluation criteria was investigated using the new J-estimation scheme. The Z-factor obtained in this study was compared with the presently used Z-factors, and the predictability of the current flaw evaluation criteria was quantitatively evaluated in consideration of the internal pressure.

Failure mechanisms and lifetime prediction methodology for polybutylene pipe in water distribution system

NASA Astrophysics Data System (ADS)

Niu, Xiqun

Polybutylene (PB) is a semicrystalline thermoplastics. It has been widely used in potable water distribution piping system. However, field practice shows that failure occurs much earlier than the expected service lifetime. What are the causes and how to appropriately evaluate its lifetime motivate this study. In this thesis, three parts of work have been done. First is the understanding of PB, which includes material thermo and mechanical characterization, aging phenomena and notch sensitivity. The second part analyzes the applicability of the existing lifetime testing method for PB. It is shown that PB is an anomaly in terms of the temperature-lifetime relation because of the fracture mechanism transition across the testing temperature range. The third part is the development of the methodology of lifetime prediction for PB pipe. The fracture process of PB pipe consists of three stages, i.e., crack initiation, slow crack growth (SCG) and crack instability. The practical lifetime of PB pipe is primarily determined by the duration of the first two stages. The mechanism of crack initiation and the quantitative estimation of the time to crack initiation are studied by employing environment stress cracking technique. A fatigue slow crack growth testing method has been developed and applied in the study of SCG. By using Paris-Erdogan equation, a model is constructed to evaluate the time for SCG. As a result, the total lifetime is determined. Through this work, the failure mechanisms of PB pipe has been analyzed and the lifetime prediction methodology has been developed.

Material engineering and fabrication experiences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Havn, T.

1995-10-01

Material selection for hydrocarbon and sea water systems is shortly described and experiences are explained. The risk of external stress corrosion cracking is discussed. Same is the need for isolation pipe spools to avoid galvanic corrosion. Possible corrosion as result of hot work reduction on platform modification work is discussed. Benefit from positive material identification is explained and the solution of a weld problem due to mix-up of filler material is shown. Experiences with cold bending and subsea material engineering are discussed and recommendations are given. Fracture mechanic techniques with purpose of avoiding costly replacement and repair welding are shownmore » by two examples. At the end the new cost reduction trend of using performance based specifications is shortly discussed with respect to material requirements.« less

On thermohydrologic conditions near high-level nuclear wastes emplaced in partially saturated fractured tuff: 1. Simulation studies with explicit consideration of fracture effects

NASA Astrophysics Data System (ADS)

Pruess, K.; Wang, J. S. Y.; Tsang, Y. W.

1990-06-01

We have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated, fractured porous rock. Formation parameters were chosen as representative of the potential nuclear waste repository site in the Topopah Spring unit of the Yucca Mountain tuffs. The presence of fractures makes the transport problem very complex, both in terms of flow geometry and physics. The numerical simulator used for our flow calculations takes into account most of the physical effects believed to be important in multiphase fluid and heat flow. It has provisions for handling the extreme nonlinearities that arise in phase transitions, component disappearances, and capillary discontinuities at fracture faces. We model a region around an infinite linear string of nuclear waste canisters, taking into account both the discrete fractures and the porous matrix. Thermohydrologic conditions in the vicinity of the waste packages are found to depend strongly on relative permeability and capillary pressure characteristics of the fractures, which are unknown at the present time. If liquid held on the rough walls of drained fractures is assumed to be mobile, strong heat pipe effects are predicted. Under these conditions the host rock will remain in two-phase conditions right up to the emplacement hole, and formation temperatures will peak near 100°C. If it is assumed that liquid cannot move along drained fractures, the region surrounding the waste packages is predicted to dry up, and formation temperatures will rise beyond 200°C. A substantial fraction of waste heat can be removed if emplacement holes are left open and ventilated, as opposed to backfilled and sealed emplacement conditions. Comparing our model predictions with observations from in situ heater experiments reported by Zimmerman and coworkers, some intriguing similarities are noted. However, for a quantitative evaluation, additional carefully controlled laboratory and field experiments will be needed.

Fracture Toughness of Z3CN20.09M Cast Stainless Steel with Long-Term Thermal Aging

NASA Astrophysics Data System (ADS)

Yu, Weiwei; Yu, Dunji; Gao, Hongbo; Xue, Fei; Chen, Xu

2017-09-01

Accelerated thermal aging tests were performed at 400 °C for nearly 18,000 h on Z3CN20.09M cast stainless steel which was used for primary coolant pipes of nuclear power plants. A series of Charpy impact tests were conducted on Z3CN20.09M after different long-term thermal aging time. The test results indicated that the Charpy impact energy of Z3CN20.09M cast stainless steel decreased rapidly at an early stage and then almost saturated after thermal aging of 10,000 h. Furthermore, J-resistance curves were measured for CT specimens of longitudinal and circumferential pipe orientations. It showed that there was no obvious difference in the fracture characteristics of Z3CN20.09M in different sampling directions. In addition, the observed stretch zone width (SZW) revealed that the value of initiation fracture toughness J SZW was significantly lower than that of fracture toughness J IC, indicating a low actual crack initiation energy due to long-term thermal aging.

Pressure vessel fracture, fatigue, and life management: PVP-Volume 233

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhandari, S.; Milella, P.P.; Pennell, W.E.

1992-01-01

This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on the effects of aging. The papers are organized in the following five areas: (1) pressure vessel life management; (2) fracture characterization using local and dual-parameter approaches; (3) stratification and thermal fatigue; (4) creep, fatigue, and fracture; and (5) integrated approach to integrity assessment of pressure components. Separate abstracts were prepared for 39 papers in this conference.

Analogue modelling of caprock failure and sediment mobilisation due to pore fluid overpressure in shallow reservoirs

NASA Astrophysics Data System (ADS)

Warsitzka, Michael; Kukowski, Nina; May, Franz

2017-04-01

Injection of CO2 in geological formations may cause excess pore fluid pressure by enhancing the fluid volume in the reservoir rock and by buoyancy-driven flow. If sediments in the reservoir and the caprock are undercompacted, pore fluid overpressure can lead to hydro-fractures in the caprock and fluidisation of sediments. Eventually, these processes trigger the formation of pipe structures, gas chimneys, gas domes or sand injections. Generally, such structures serve as high permeable pathways for fluid migration through a low-permeable seal layer and have to be considered in risk assessment or modelling of caprock integrity of CO2 storage sites. We applied scaled analogue experiments to characterise and quantify mechanisms determining the onset and migration of hydro-fractures in a low-permeable, cohesive caprock and fluidisation of unconsolidated sediments of the reservoir layer. The caprock is simulated by different types of cohesive powder. The reservoir layer consists of granulates with small particle density. Air injected through the base of the experiment and additionally through a single needle valve reaching into the analogue material is applied to generate fluid pressure within the materials. With this procedure, regional fluid pressure increase or a point-like local fluid pressure increase (e.g. injection well), respectively, can be simulated. The deformation in the analogue materials is analysed with a particle tracking imaging velocimetry technique. Pressure sensors at the base of the experiment and in the needle valve record the air pressure during an experimental run. The structural evolution observed in the experiments reveal that the cohesive cap rock first forms a dome-like anticline. Extensional fractures occur at the hinges of the anticline. A further increase of fluid pressure causes a migration of this fractures towards the surface, which is followed by intrusion of reservoir material into the fractures and the collapse of the anticline. The breakthrough of the fractures at the surface is accompanied by a significant drop of air pressure at the base of the analogue materials. The width of the dome shaped uplift is narrower and the initiating fluid pressure in the needle valve is lower, if the fluid pressure at the base of the experiment is larger. The experimental outcomes help to evaluate if the injection of CO2 into a reservoir potentially provokes initiation or reactivation of fractures and sediment mobilisation structures.

FROMS3D: New Software for 3-D Visualization of Fracture Network System in Fractured Rock Masses

NASA Astrophysics Data System (ADS)

Noh, Y. H.; Um, J. G.; Choi, Y.

2014-12-01

A new software (FROMS3D) is presented to visualize fracture network system in 3-D. The software consists of several modules that play roles in management of borehole and field fracture data, fracture network modelling, visualization of fracture geometry in 3-D and calculation and visualization of intersections and equivalent pipes between fractures. Intel Parallel Studio XE 2013, Visual Studio.NET 2010 and the open source VTK library were utilized as development tools to efficiently implement the modules and the graphical user interface of the software. The results have suggested that the developed software is effective in visualizing 3-D fracture network system, and can provide useful information to tackle the engineering geological problems related to strength, deformability and hydraulic behaviors of the fractured rock masses.

ORNL Pre-test Analyses of A Large-scale Experiment in STYLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Paul T; Yin, Shengjun; Klasky, Hilda B

Oak Ridge National Laboratory (ORNL) is conducting a series of numerical analyses to simulate a large scale mock-up experiment planned within the European Network for Structural Integrity for Lifetime Management non-RPV Components (STYLE). STYLE is a European cooperative effort to assess the structural integrity of (non-reactor pressure vessel) reactor coolant pressure boundary components relevant to ageing and life-time management and to integrate the knowledge created in the project into mainstream nuclear industry assessment codes. ORNL contributes work-in-kind support to STYLE Work Package 2 (Numerical Analysis/Advanced Tools) and Work Package 3 (Engineering Assessment Methods/LBB Analyses). This paper summarizes the current statusmore » of ORNL analyses of the STYLE Mock-Up3 large-scale experiment to simulate and evaluate crack growth in a cladded ferritic pipe. The analyses are being performed in two parts. In the first part, advanced fracture mechanics models are being developed and performed to evaluate several experiment designs taking into account the capabilities of the test facility while satisfying the test objectives. Then these advanced fracture mechanics models will be utilized to simulate the crack growth in the large scale mock-up test. For the second part, the recently developed ORNL SIAM-PFM open-source, cross-platform, probabilistic computational tool will be used to generate an alternative assessment for comparison with the advanced fracture mechanics model results. The SIAM-PFM probabilistic analysis of the Mock-Up3 experiment will utilize fracture modules that are installed into a general probabilistic framework. The probabilistic results of the Mock-Up3 experiment obtained from SIAM-PFM will be compared to those results generated using the deterministic 3D nonlinear finite-element modeling approach. The objective of the probabilistic analysis is to provide uncertainty bounds that will assist in assessing the more detailed 3D finite-element solutions and to also assess the level of confidence that can be placed in the best-estimate finiteelement solutions.« less

Ductile fracture theories for pressurised pipes and containers

NASA Technical Reports Server (NTRS)

Erdogan, F.

1976-01-01

Two mechanisms of fracture are distinguished. Plane strain fractures occur in materials which do not undergo large-scale plastic deformations prior to and during a possible fracture deformation. Plane stress or high energy fractures are generally accompanied by large inelastic deformations. Theories for analyzing plane stress are based on the concepts of critical crack opening stretch, K(R) characterization, J-integral, and plastic instability. This last is considered in some detail. The ductile fracture process involves fracture initiation followed by a stable crack growth and the onset of unstable fracture propagation. The ductile fracture propagation process may be characterized by either a multiparameter (discrete) model, or some type of a resistance curve which may be considered as a continuous model expressed graphically. These models are studied and an alternative model is also proposed for ductile fractures which cannot be modeled as progressive crack growth phenomena.

Piping Inelastic Fracture Mechanics Analysis.

DTIC Science & Technology

1980-06-30

LOCATIONd THERM4AL SLEEVE REPAIR WELD TYPE 310 STAINLESS TEL C FVICt AREA SPO PCE Fig. 3.1-Duane Arnold recirculation-inlet-nozzle safe end configuration...Environment The most commonly used materials in the LWR piping system are Types 304 and 316 austenitic stainless steel ( cast /wrought). However, for various...seismic and water hammering), the contribu- tion of the residual stress due to the welding plays a very important role in initiation and propagation

Numerical study of transitional flow in fractures: the role of roughness on the road to turbulence

NASA Astrophysics Data System (ADS)

Linga, G.; Mathiesen, J.

2017-12-01

In aquifers and petroleum reservoirs, fractures are ubiquitous, and the majority of the fluid transport in such systems often occurs through fracture networks. Knowledge of the flow properties in the single fractures that together form the networks is hence necessary for safe operation downhole. Non-linear, high-velocity flow in such systems is of particular importance for geothermics, since turbulent mixing is known to increase heat conduction by several orders of magnitude. This is of importance both in terms of storing and recovering heat from aquifers. On the other hand, flow in rough fractures is interesting from a turbulence perspective. The onset of turbulence in pipes and channels is a phenomenon that historically has received broad attention since the early experiments by Reynolds, and only during the last decades, the phenomenon is beginning to be fully understood. However, in the presence of roughness, much less is known. In this work, we present comprehensive numerical simulations of flow in synthetic rough channels, representing single fracture joints. Using the finite element method, we solve the full-fledged, time-dependent Navier-Stokes equations for flow in the channels, from laminar flow, through transitional, to turbulent flow. We link the descriptions of microscopic to macroscopic properties, using geometric properties such as effective aperture, paying particular attention to the role of inertia and roughness for the transport properties of the channels. Finally, we discuss implications of our study for the transition to turbulence in the presence of roughness.

Gas-Recovery System

DOEpatents

Heckman, R. A.

1971-12-14

Nuclear explosions have been proposed as a means for recovering gas from underground gas-bearing rock formations. In present practice, the nuclear device is positioned at the end of a long pipe which is subsequently filled with grout or concrete. After the device is exploded, the grout is drilled through to provide a flow path for the released gas to the ground surface. As settled grout is brittle, often the compressive shock of the explosion fractures the grout and deforms the pipe so that it may not be removed nor reused. In addition, the pipe is sometimes pinched off completely and the gas flow is totally obstructed. (2 claims)

Gas-recovery system

DOEpatents

Heckman, R.A.

1971-12-14

Nuclear explosions have been proposed as a means for recovering gas from underground gas-bearing rock formations. In present practice, the nuclear device is positioned at the end of a long pipe which is subsequently filled with grout or concrete. After the device is exploded, the grout is drilled through to provide a flow path for the released gas to the ground surface. As settled grout is brittle, often the compressive shock of the explosion fractures the grout and deforms the pipe so that it may not be removed nor reused. In addition, the pipe is sometimes pinched off completely and the gas flow is totally obstructed. (2 claims)

U-Pb dating of uranium deposits in collapse breccia pipes of the Grand Canyon region

USGS Publications Warehouse

Ludwig, K. R.; Simmons, K.R.

1992-01-01

Two major periods of uranium mineralization are indicated by U-Pb isotope dating of uranium ores from collapse breccia pipes in the Grand Canyon region, northern Arizona. The Hack 2 and 3, Kanab North, and EZ 1 and 2 orebodies apparently formed in the interval of 200 ?? 20 Ma, similar to ages inferred for strata-bound, Late Triassic-hosted uranium deposits in southern Utah and northern Arizona. Samples from the Grand Canyon and Pine Nut pipes, however, indicate a distinctly older age of about 260 Ma. The clustering in ages for a variety of uranium deposits at about the age of the lower part of the Chinle Formation (Late Triassic) suggests that uranium in these deposits may have been derived by leaching from volcanic ash in the Chinle and mobilized by ground-water movement. Pb isotope ratios of galenas in mineralized pipes are more radiogenic than those of sulfides from either uranium-poor pipes or occurrences away from pipes. Fluids which passed through the pipes had interacted with the Proterozoic basement, possibly through the vertical fractures which influenced the location and evolution of the pipes themselves. -from Authors

Gaseous Detonation-Driven Fracture of Tubes

DTIC Science & Technology

2004-03-01

understanding, in addition to leading to safer piping system design in nuclear power plants, can also assist accident investigators in learning what type...load, there are derived expressions in the literature from which one can learn about some essential features of mode I dynamic fracture. For a...along a 0.2-mm deep longitudinal groove. Pressure histories were measured by pressure transducers mounted inside the tube, axial and circumferen- tial

Cryogenic Heat Pipe Experiment (CRYOHP)

NASA Technical Reports Server (NTRS)

Mcintosh, Roy

1992-01-01

The objective of the CRYOHP experiment is to conduct a shuttle experiment that demonstrates the reliable operation of two oxygen heat pipes in microgravity. The experiment will perform the following tasks: (1) demonstrate startup of the pipes from the supercritical state; (2) measure the heat transport capacity of the pipes; (3) measure evaporator and condenser film coefficients; and (4) work shuttle safety issues. The approach for the experiment is as follows: (1) fly two axially grooved oxygen heat pipes attached to mechanical stirling cycle tactical coolers; (2) integrate experiment in hitch-hiker canister; and (3) fly on shuttle and control from ground.

ERTS-C (Landsat 3) cryogenic heat pipe experiment definition

NASA Technical Reports Server (NTRS)

Brennan, P. J.; Kroliczek, E. J.

1975-01-01

A flight experiment designed to demonstrate current cryogenic heat pipe technology was defined and evaluated. The experiment package developed is specifically configured for flight aboard an ERTS type spacecraft. Two types of heat pipes were included as part of the experiment package: a transporter heat pipe and a thermal diode heat pipe. Each was tested in various operating modes. Performance data obtained from the experiment are applicable to the design of cryogenic systems for detector cooling, including applications where periodic high cooler temperatures are experienced as a result of cyclic energy inputs.

Kinetics and microscopic processes of long term fracture in polyethylene piping materials

NASA Astrophysics Data System (ADS)

Brown, N.; Lu, X.

1992-07-01

The report contains 9 completed works as follows: The Dependence of Slow Crack Growth in a Polyethylene Copolymer on Testing Temperature and Morphology; A Test of Slow Crack Growth Failure of PE Under Constant Load; Effect of Annealing on Slow Crack Growth in an Ethylene-Hexene Copolymer; The Fundamental Material Parameters that Govern Slow Crack Growth in Linear Polyethylene; Slow Crack Growth in Blends of HDPE and UHMWPE; The Mechanism of Fatigue Failure in a Polyethylene Copolymer; PENT Quality Control Test for PE Gas Pipes and Resins; International Round Robin Study of a Fatigue Test Approach to the Ranking of Polyethylene Pipe Material; and Proposed ASTM Specification for ASTM F17.40 Test Methods Committee.

Physical characterization and recovery of corroded fingerprint impressions from postblast copper pipe bomb fragments.

PubMed

Bond, John W; Brady, Thomas F

2013-05-01

Pipe bombs made from 1 mm thick copper pipe were detonated with a low explosive power powder. Analysis of the physical characteristics of fragments revealed that the copper had undergone work hardening with an increased Vickers Hardness of 107HV1 compared with 80HV1 for unexploded copper pipe. Mean plastic strain prior to fracture was calculated at 0.28 showing evidence of both plastic deformation and wall thinning. An examination of the external surface showed microfractures running parallel with the length of the pipe at approximately 100 μm intervals and 1-2 μm in width. Many larger fragments had folded "inside out" making the original outside surface inaccessible and difficult to fold back through work hardening. A visual examination for fingerprint corrosion revealed ridge details on several fragments that were enhanced by selective digital mapping of colors reflected from the surface of the copper. One of these fingerprints was identified partially to the original donor. © 2013 American Academy of Forensic Sciences.

Crack instability analysis methods for leak-before-break program in piping systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattar Neto, M.; Maneschy, E.; Nobrega, P.G.B. da

1995-11-01

The instability evaluation of cracks in piping systems is a step that is considered when a high-energy line is investigated in a leak-before-break (LBB) program. Different approaches have been used to assess stability of cracks: (a) local flow stress (LFS); (b) limit load (LL); (c) elastic-plastic fracture mechanics (EPFM) as J-integral versus tearing modulus (J-T) analysis. The first two methods are used for high ductile materials, when it is assumed that remaining ligament of the cracked pipe section becomes fully plastic prior to crack extension. EPFM is considered for low ductile piping when the material reaches unstable ductile tearing priormore » to plastic collapse in the net section. In this paper the LFS, LL and EPFM J-T methodologies were applied to calculate failure loads in circumferential through-wall cracked pipes with different materials, geometries and loads. It presents a comparison among the results obtained from the above three formulations and also compares them with experimental data available in the literature.« less

New software for 3D fracture network analysis and visualization

NASA Astrophysics Data System (ADS)

Song, J.; Noh, Y.; Choi, Y.; Um, J.; Hwang, S.

2013-12-01

This study presents new software to perform analysis and visualization of the fracture network system in 3D. The developed software modules for the analysis and visualization, such as BOUNDARY, DISK3D, FNTWK3D, CSECT and BDM, have been developed using Microsoft Visual Basic.NET and Visualization TookKit (VTK) open-source library. Two case studies revealed that each module plays a role in construction of analysis domain, visualization of fracture geometry in 3D, calculation of equivalent pipes, production of cross-section map and management of borehole data, respectively. The developed software for analysis and visualization of the 3D fractured rock mass can be used to tackle the geomechanical problems related to strength, deformability and hydraulic behaviors of the fractured rock masses.

Cavitation onset caused by acceleration

PubMed Central

Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J.; Thomson, Scott L.; Hurd, Randy

2017-01-01

Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation. PMID:28739956

Cavitation onset caused by acceleration.

PubMed

Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J; Thomson, Scott L; Hurd, Randy; Truscott, Tadd T

2017-07-24

Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation.

Cavitation onset caused by acceleration

NASA Astrophysics Data System (ADS)

Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J.; Thomson, Scott L.; Hurd, Randy; Truscott, Tadd T.

2017-08-01

Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation.

Tectonic fault monitoring at open pit mine at Zarnitsa Kimberlite Pipe

NASA Astrophysics Data System (ADS)

Vostrikov, VI; Polotnyanko, NS; Trofimov, AS; Potaka, AA

2018-03-01

The article describes application of Karier instrumentation designed at the Institute of Mining to study fracture formation in rocks. The instrumentation composed of three sensors was used to control widening of a tectonic fault intersecting an open pit mine at Zarnitsa Kimberlite Pipe in Yakutia. The monitoring between 28 November and 28 December in 2016 recorded convergence of the fault walls from one side of the open pit mine and widening from the other side. After production blasts, the fault first grows in width and then recovers.

LDEF transverse flat plate heat pipe experiment /S1005/. [Long Duration Exposure Facility

NASA Technical Reports Server (NTRS)

Robinson, G. A., Jr.

1979-01-01

The paper describes the Transverse Flat Plate Heat Pipe Experiment. A transverse flat plate heat pipe is a thermal control device that serves the dual function of temperature control and mounting base for electronic equipment. In its ultimate application, the pipe would be a lightweight structure member that could be configured in a platform or enclosure and provide temperature control for large space structures, flight experiments, equipment, etc. The objective of the LDEF flight experiment is to evaluate the zero-g performance of a number of transverse flat plate heat pipe modules. Performance will include: (1) the pipes transport capability, (2) temperature drop, and (3) ability to maintain temperature over varying duty cycles and environments. Performance degradation, if any, will be monitored over the length of the LDEF mission. This information is necessary if heat pipes are to be considered for system designs where they offer benefits not available with other thermal control techniques, such as minimum weight penalty, long-life heat pipe/structural members.

Fracture characterization in a deep geothermal reservoir

NASA Astrophysics Data System (ADS)

Rühaak, Wolfram; Hehn, Vera; Hassanzadegan, Alireza; Tischner, Torsten

2017-04-01

At the geothermal research drilling Horstberg in North West Germany studies for the characterization of a vertical fracture are performed. The fracture was created by a massive hydraulic stimulation in 2003 in approx. 3700 m depth within rocks of the middle Buntsandstein. The fracture surface is in the order of 100,000 m2, depending on the flow rate at which water is injected. Besides hydraulic characterization, multiple tracer tests are planned. At the depth of interest the reservoir temperature is around 150 °C, pressure is around 600 bar (60 MPa) and due to salinity the water density is around 1200 kg/m3. Knowledge of tracer stability and behavior at these reservoir conditions is limited. Additionally, the planned tracer tests will be performed within one single borehole. In a closed cycle water is injected into the inner pipe of the well (tubing), which is separated by a permanent packer from the outer pipe (annulus). The water is produced back from the annulus approximately 150 m above the injection point. Thus, the circulation of thermal water between two sandstone layers via an artificial fracture can be achieved. Tests will be carried out with different flow rates and accordingly with different pressures, resulting in different fracture areas. Due to this test setup tracer signals will be stacked and will remain for a longer time in the fracture - which is the reason why different tracers are required. For an optimal characterization both conservative and reactive tracers will be used and different injection methods (continuous, instantaneous and pulsed) will be applied. For a proper setup of the tracer test numerical modelling studies are performed in advance. The relevant thermal, hydraulic and chemical processes (mainly adsorption and degredation) are coupled, resulting in a THC model; additionally the dependence of fracture aperture and area on fluid pressure has to be considered. Instead of applying a mechanically coupled model (THMC) a simplified approach is applied which takes the pressure dependence of the fracture permeability into account by using constitutive relations. Results of this modeling study will be presented together with details of the planned field study.

Finite volume method and multigrid acceleration in modelling of rapid crack propagation in full-scale pipe test

NASA Astrophysics Data System (ADS)

Ivankovic, A.; Muzaferija, S.; Demirdzic, I.

1997-07-01

Rapid Crack Propagation (RCP) along pressurised plastic pipes is by far the most dangerous pipe failure mode. Despite the economic benefits offered by increasing pipe size and operating pressure, both strategies increase the risk and the potential consequences of RCP. It is therefore extremely important to account for RCP in establishing the safe operational conditions. Combined experimental-numerical study is the only reliable approach of addressing the problem, and extensive research is undertaken by various fracture groups (e.g. Southwest Research Institute - USA, Imperial College - UK). This paper presents numerical results from finite volume modelling of full-scale test on medium density polyethylene gas pressurised pipes. The crack speed and pressure profile are prescribed in the analysis. Both steady-state and transient RCPs are considered, and the comparison between the two shown. The steady-state results are efficiently achieved employing a full multigrid acceleration technique, where sets of progressively finer grids are used in V-cycles. Also, the effect of inelastic behaviour of polyethylene on RCP results is demonstrated.

Evaluation of flaws in carbon steel piping. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zahoor, A.; Gamble, R.M.; Mehta, H.S.

1986-10-01

The objective of this program was to develop flaw evaluation procedures and allowable flaw sizes for ferritic piping used in light water reactor (LWR) power generation facilities. The program results provide relevant ASME Code groups with the information necessary to define flaw evaluation procedures, allowable flaw sizes, and their associated bases for Section XI of the code. Because there are several possible flaw-related failure modes for ferritic piping over the LWR operating temperature range, three analysis methods were employed to develop the evaluation procedures. These include limit load analysis for plastic collapse, elastic plastic fracture mechanics (EPFM) analysis for ductilemore » tearing, and linear elastic fracture mechanics (LEFM) analysis for non ductile crack extension. To ensure the appropriate analysis method is used in an evaluation, a step by step procedure also is provided to identify the relevant acceptance standard or procedure on a case by case basis. The tensile strength and toughness properties required to complete the flaw evaluation for any of the three analysis methods are included in the evaluation procedure. The flaw evaluation standards are provided in tabular form for the plastic collapse and ductile tearing modes, where the allowable part through flaw depth is defined as a function of load and flaw length. For non ductile crack extension, linear elastic fracture mechanics analysis methods, similar to those in Appendix A of Section XI, are defined. Evaluation flaw sizes and procedures are developed for both longitudinal and circumferential flaw orientations and normal/upset and emergency/faulted operating conditions. The tables are based on margins on load of 2.77 and 1.39 for circumferential flaws and 3.0 and 1.5 for longitudinal flaws for normal/upset and emergency/faulted conditions, respectively.« less

­­Clastic Pipes on Mars: Evidence for a Near Surface Groundwater System

NASA Astrophysics Data System (ADS)

Wheatley, D. F.; Chan, M. A.; Okubo, C. H.

2017-12-01

Clastic pipes, a type of vertical, columnar injectite, occur throughout the terrestrial stratigraphic record and are identified across many Martian terrains. Terrestrial pipe analogs can aid in identifying clastic pipes on Mars to understand their formation processes and their implications for a past near-surface groundwater system. On Earth, clastic pipes form through fluidization of overpressurized sediment. Fluidization occurs when the upward frictional (i.e., drag) forces of escaping fluids overpower the downward acting gravitational force. To create the forces necessary for pipe formation requires overpressurization of a body of water-saturated porous media overlain by a low permeability confining layer. As the pressure builds, the confining layer eventually fractures and the escaping fluids fluidize the porous sediment causing the sediment to behave like a fluid. These specific formation conditions record evidence of a violent release of fluid-suspended sediment including brecciation of the host and sealing material, internal outward grading/sorting that results in a coarser-grained commonly better cemented outer rind, traction structures, and a cylindrical geometry. Pipes form self-organized, dispersed spatial relationships due to the efficient diffusion of overpressured zones in the subsurface and the expulsion of sediment under pressure. Martian pipes occur across the northern lowlands, dichotomy boundary, and southern highlands in various forms of erosional relief ranging from newer eruption structures to eroded cylindrical/conical mounds with raised rims to highly eroded mounds/hills. Similar to terrestrial examples, Martian pipes form in evenly-spaced, self-organized arrangements. The pipes are typically internally massive with a raised outer rim (interpreted as a sorted, coarser-grained, better-cemented rim). This evidence indicates that Martian pipes formed through fluidization, which requires a near-surface groundwater system. Pipes create a window into the subsurface by excavating subsurface sediment and waters. After emplacement, pipes can also act as fluid conduits, channeling post-depositional fluid flow. The preferential porosity and flow paths may make the pipes an ideal exploration target for microbial life.

Multiphase, multicomponent flow and transport models for Nuclear Test-Ban Treaty monitoring and nuclear waste disposal applications

NASA Astrophysics Data System (ADS)

Jordan, Amy

Open challenges remain in using numerical models of subsurface flow and transport systems to make useful predictions related to nuclear waste storage and nonproliferation. The work presented here addresses the sensitivity of model results to unknown parameters, states, and processes, particularly uncertainties related to incorporating previously unrepresented processes (e.g., explosion-induced fracturing, hydrous mineral dehydration) into a subsurface flow and transport numerical simulator. The Finite Element Heat and Mass (FEHM) transfer code is used for all numerical models in this research. An experimental campaign intended to validate the predictive capability of numerical models that include the strongly coupled thermal, hydrological, and chemical processes in bedded salt is also presented. Underground nuclear explosions (UNEs) produce radionuclide gases that may seep to the surface over weeks to months. The estimated timing of gas arrival at the surface may be used to deploy personnel and equipment to the site of a suspected UNE, if allowed under the terms of the Comprehensive Nuclear Test-Ban Treaty. A model was developed using FEHM that considers barometrically pumped gas transport through a simplified fractured medium and was used to quantify the impact of uncertainties in hydrologic parameters (fracture aperture, matrix permeability, porosity, and saturation) and season of detonation on the timing of gas breakthrough. Numerical sensitivity analyses were performed for the case of a 1 kt UNE at a 400 m burial depth. Gas arrival time was found to be most affected by matrix permeability and fracture aperture. Gases having higher diffusivity were more sensitive to uncertainty in the rock properties. The effect of seasonality in the barometric pressure forcing was found to be important, with detonations in March the least likely to be detectable based on barometric data for Rainier Mesa, Nevada. Monte Carlo modeling was also used to predict the window of opportunity for Xe-133 detection from a 1 kt UNE at Rainier Mesa, with and without matching the model to SF6 and He-3 data from the 1993 Non Proliferation Experiment. Results from the data-blind Monte Carlo simulations were similar, but were biased towards earlier arrival time and less likely to show detectable Xe-133. The second study, also related to nuclear nonproliferation compliance, considered the effect of barometric pumping on predicted Xe-133 breakthrough time in a Monte Carlo framework. Barometric pumping of gas through explosion-fractured rock was investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks for two rock types (granite and saturated tuff) and three depths of burial were integrated into a numerical model driven by surface pressure signals of differing amplitude and variability. Matrix porosity and maximum fracture aperture had the greatest impact on gas breakthrough time and window of opportunity for detection. Differences in model sensitivity for granite and tuff simulations highlight the importance of accurately simulating the fracture network. From Monte Carlo simulations using randomly generated hydrogeologic parameters, normalized probability of detection curves showed differences in optimal sampling time for granite and tuff. Granite breakthrough was earlier, as was breakthrough in realizations with greater variance of barometric pressure. Next, heat-generating nuclear waste (HGNW) disposal in bedded salt during the first two years after waste emplacement was explored using numerical simulations tied to experiments of hydrous mineral dehydration. Heating impure salt samples to temperatures of 265°C released water in amounts greater than 20% by mass of hydrous minerals and clays. Experimental data for water loss at several temperatures were averaged to produce a water source model that was then implemented in FEHM. Simulations using this dehydration model were used to predict temperature, moisture, and porosity after heating by 750W waste canisters, assuming hydrous mineral mass fractions from 0--10%. The formation of a three-phase heat pipe (with counter-circulation of vapor and brine) occurs as water vapor is driven away from the heat source, condenses, and flows back towards the heat source, leading to changes in porosity, permeability, temperature, saturation, and thermal conductivity of the backfill salt surrounding the waste canisters. Heat pipe formation depends on temperature, moisture availability and fluid mobility. In certain cases, dehydration of hydrous minerals provided sufficient additional moisture to push the system into a sustained heat pipe where simulations neglecting this process did not. A laboratory-scale experiment (˜1 m3) using granular salt was conducted to gain a better understanding of the complex coupled processes involved in liquid, vapor, and solid transport occurring around heated nuclear waste in crushed salt, which could be a mode of disposal for HGNW. The experiment was designed to study transport processes in the system that have not been satisfactorily quantified in prior work. Initial results from the experimental effort offer promising insights. (Abstract shortened by UMI.).

Procedure improves line pipe Charpy test interpretation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenfeld, M.J.

1997-04-14

The Charpy V-notch (CVN) impact test is a method of characterizing a line-pipe material`s notch toughness and resistance to fracture growth. Although CVN testing of line pipe material is routine, test results are sometimes misinterpreted because of specimen size and load rate on actual toughness transition behavior. These effects are readily accounted for by a simple mathematical procedure, offered here, which enables extrapolation of the full-scale transition curve from as little as a single subsize specimen test. This procedure is useful when the toughness transition curve is incomplete or nonexistent. Toughness data may be incomplete because the API 5L toughnessmore » test establishes minimum performance at a single temperature, which does not reveal the full transition curve. Toughness data may be nonexistent because the first requirements for toughness testing of line pipe appeared in the 16th Edition of API 5LX in 1969, and those requirements remain at the option of the purchaser today.« less

Finite-Element Analysis of Crack Arrest Properties of Fiber Reinforced Composites Application in Semi-Elliptical Cracked Pipelines

NASA Astrophysics Data System (ADS)

Wang, Linyuan; Song, Shulei; Deng, Hongbo; Zhong, Kai

2018-04-01

In nowadays, repair method using fiber reinforced composites as the mainstream pipe repair technology, it can provide security for X100 high-grade steel energy long-distance pipelines in engineering. In this paper, analysis of cracked X100 high-grade steel pipe was conducted, simulation analysis was made on structure of pipes and crack arresters (CAs) to obtain the J-integral value in virtue of ANSYS Workbench finite element software and evaluation on crack arrest effects was done through measured elastic-plastic fracture mechanics parameter J-integral and the crack arrest coefficient K, in a bid to summarize effect laws of composite CAs and size of pipes and cracks for repairing CAs. The results indicate that the K value is correlated with laying angle λ, laying length L2/D1, laying thickness T1/T2of CAs, crack depth c/T1 and crack length a/c, and calculate recommended parameters for repairing fiber reinforced composite CAs in terms of two different crack forms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hart, F.L.

A method is described for exerting forces on a subterranean formation for fracturing and increasing the width of a fracture wherein polymerizable materials capable of forming popcorn polymer are placed in the formation and polymerized in situ. Popcorn polymer is a hard, porous opaque material that is not soluble in ordinary solvents. The occurrence of popcorn polymer is well-known in chemical plants, such as for example a synthetic rubber plant. The forces that are exerted by the forming popcorn polymer have been known to split extra heavy steel pipe, snap a number of bolts, and force bubble traps upward throughmore » towers and, in general, exhibit forces greatly in excess of that needed to fracture and separate subterranean formations. (8 claims)« less

An experimental study of geyser-like flows induced by a pressurized air pocket

NASA Astrophysics Data System (ADS)

Elayeb, I. S.; Leon, A.; Choi, Y.; Alnahit, A. O.

2015-12-01

Previous studies argues that the entrapment of pressurized air pockets within combined sewer systems can produce geyser flows, which is an oscillating jetting of a mixture of gas-liquid flows. To verify that pressurized air pockets can effectively produce geysers, laboratory experiments were conducted. However, past experiments were conducted in relatively small-scale apparatus (i.e. maximum φ2" vertical shaft). This study conducted a set of experiments in a larger apparatus. The experimental setup consists of an upstream head tank, a downstream head tank, a horizontal pipe (46.5ft long, φ6") and a vertical pipe (10ft long, φ6"). The initial condition for the experiments is constant flow discharge through the horizontal pipe. The experiments are initiated by injecting an air pocket with pre-determined volume and pressure at the upstream end of the horizontal pipe. The air pocket propagates through the horizontal pipe until it arrives to the vertical shaft, where it is released producing a geyser-like flow. Three flow rates in the horizontal pipe and three injected air pressures were tested. The variables measured were pressure at two locations in the horizontal pipe and two locations in the vertical pipe. High resolution videos at two regions in the vertical shaft were also recorded. To gain further insights in the physics of air-water interaction, the laboratory experiments were complemented with numerical simulations conducted using a commercial 3D CFD model, previously validated with experiments.

Heavy-section steel technology program. Semiannual progress report for period ending February 28, 1973

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1974-02-01

The materials investigations under the HSST program are divided into studies of unirradiated materials and studies of irradiation effects. The studies of unirradiated materials, which include inspection, characterization, metallurgy, variability determinations, transition temperature investigations, fracture mechanics studies, and fatigue-crack propagation tests, are discussed. The investigations of irradiated materials include studies of radiation effects on A-533-B steel. Results of studies on thick pressure vessels and pipes of ASTM A508 steel are also reported along with results of studies on Mode III crack extension in reactor piping. (JRD)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Kyoung Mo; Jee, Kye Kwang; Pyo, Chang Ryul

The basis of the leak before break (LBB) concept is to demonstrate that piping will leak significantly before a double ended guillotine break (DEGB) occurs. This is demonstrated by quantifying and evaluating the leak process and prescribing safe shutdown of the plant on the basis of the monitored leak rate. The application of LBB for power plant design has reduced plant cost while improving plant integrity. Several evaluations employing LBB analysis on system piping based on DEGB design have been completed. However, the application of LBB on main steam (MS) piping, which is LBB applicable piping, has not been performedmore » due to several uncertainties associated with occurrence of steam hammer and dynamic strain aging (DSA). The objective of this paper is to demonstrate the applicability of the LBB design concept to main steam lines manufactured with SA106 Gr.C carbon steel. Based on the material properties, including fracture toughness and tensile properties obtained from the comprehensive material tests for base and weld metals, a parametric study was performed as described in this paper. The PICEP code was used to determine leak size crack (LSC) and the FLET code was used to perform the stability assessment of MS piping. The effects of material properties obtained from tests were evaluated to determine the LBB applicability for the MS piping. It can be shown from this parametric study that the MS piping has a high possibility of design using LBB analysis.« less

String and Sticky Tape Experiments: Light Pipes, Hydrostatics, Surface Tension and a Milk Carton.

ERIC Educational Resources Information Center

Edge, R. D., Ed.

1984-01-01

Describes a demonstration of light pipes using low-cost materials, relating it to fiber optics communication. Also provides several experiments in hydrostatics and hydrodynamics using the materials for light pipe. (JM)

Development of a new software for analyzing 3-D fracture network

NASA Astrophysics Data System (ADS)

Um, Jeong-Gi; Noh, Young-Hwan; Choi, Yosoon

2014-05-01

A new software is presented to analyze fracture network in 3-D. Recently, we completed the software package based on information given in EGU2013. The software consists of several modules that play roles in management of borehole data, stochastic modelling of fracture network, construction of analysis domain, visualization of fracture geometry in 3-D, calculation of equivalent pipes and production of cross-section diagrams. Intel Parallel Studio XE 2013, Visual Studio.NET 2010 and the open source VTK library were utilized as development tools to efficiently implement the modules and the graphical user interface of the software. A case study was performed to analyze 3-D fracture network system at the Upper Devonian Grosmont Formation in Alberta, Canada. The results have suggested that the developed software is effective in modelling and visualizing 3-D fracture network system, and can provide useful information to tackle the geomechanical problems related to strength, deformability and hydraulic behaviours of the fractured rock masses. This presentation describes the concept and details of the development and implementation of the software.

Fracture Analysis of Welded Type 304 Stainless Steel Pipe

DTIC Science & Technology

1986-11-01

American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code . In order to accomplish these objectives, a series of seven full...Mechanical Engineers Boiler and Pressure Vessel Code , Section XI IWB-3640 (Winter Addenda 1983). 5. Ranganath, S., and U.S. Mehta, "Engineering Methods for

Long Duration Exposure Facility (LDEF) low-temperature Heat Pipe Experiment Package (HEPP) flight results

NASA Technical Reports Server (NTRS)

Mcintosh, Roy; Mccreight, Craig; Brennan, Patrick J.

1992-01-01

The Low Temperature Heat Pipe Flight Experiment (HEPP) is a fairly complicated thermal control experiment that was designed to evaluate the performance of two different low temperature ethane heat pipes and a n-Heptane Phase Change Material (PCM) canister. A total of 388 days of continuous operation with an axially grooved aluminum fixed conductance heat pipe of axially grooved stainless steel heat pipe diode was demonstrated before the EDS batteries lost power. The inability of the HEPP's radiator to cool below 190 K in flight prevented freezing of the PCM and the opportunity to conduct transport tests with the heat pipes. Post flight tests showed that the heat pipes and the PCM are still functioning. This paper presents a summary of the flight data analysis for the HEPP and its related support systems. Pre and post-flight thermal vacuum tests results are presented for the HEPP thermal control system along with individual heat pipe performance and PCM behavior. Appropriate SIG related systems data will also be included along with a 'lessons learned' summary.

The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD

NASA Astrophysics Data System (ADS)

Thienel, Lee; Stouffer, Chuck

1995-09-01

This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.

The Cryogenic Test Bed experiments: Cryogenic heat pipe flight experiment CRYOHP (STS-53). Cryogenic two phase flight experiment CRYOTP (STS-62). Cryogenic flexible diode flight experiment CRYOFD

NASA Technical Reports Server (NTRS)

Thienel, Lee; Stouffer, Chuck

1995-01-01

This paper presents an overview of the Cryogenic Test Bed (CTB) experiments including experiment results, integration techniques used, and lessons learned during integration, test and flight phases of the Cryogenic Heat Pipe Flight Experiment (STS-53) and the Cryogenic Two Phase Flight Experiment (OAST-2, STS-62). We will also discuss the Cryogenic Flexible Diode Heat Pipe (CRYOFD) experiment which will fly in the 1996/97 time frame and the fourth flight of the CTB which will fly in the 1997/98 time frame. The two missions tested two oxygen axially grooved heat pipes, a nitrogen fibrous wick heat pipe and a 2-methylpentane phase change material thermal storage unit. Techniques were found for solving problems with vibration from the cryo-collers transmitted through the compressors and the cold heads, and mounting the heat pipe without introducing parasitic heat leaks. A thermally conductive interface material was selected that would meet the requirements and perform over the temperature range of 55 to 300 K. Problems are discussed with the bi-metallic thermostats used for heater circuit protection and the S-Glass suspension straps originally used to secure the BETSU PCM in the CRYOTP mission. Flight results will be compared to 1-g test results and differences will be discussed.

Fate of hydraulic fracturing chemicals under down-hole conditions

NASA Astrophysics Data System (ADS)

Blotevogel, J.; Kahrilas, G.; Corrin, E. R.; Borch, T.

2013-12-01

Hydraulic fracturing is a method to increase the yield of oil and natural gas extraction from unconventional rock formations. The process of hydrofracturing occurs via injecting water, sand, and chemicals into the production well and subjecting this mixture to high pressures to crack the rock shale, allowing increased amounts of gas and oil to seep out of the target formation. Typical constituents of the chemical mixtures are biocides, which are applied to inhibit growth of sulfate reducing bacteria in order to prevent pipe corrosion and production of hazardous gases. However, very little is known about the persistence, fate, and activity of biocides when subjected to the high temperatures and pressures of down-hole conditions. Thus, the objective of this talk is to present data from ongoing experiments focused on determining the fate of biocides commonly used for hydraulic fracturing under conditions simulating down-hole environments. Using stainless steel reactors, the high pressures and temperatures of down-hole conditions in the Marcellus shale are simulated, while concentration, speciation, and degradation of priority biocides are observed as a function of time, using primarily LC/MS techniques. The impact of water quality, shale, temperature, and pressure on the transformation kinetics and pathways of biocides will be discussed. Finally, field samples (both sediments and flowback brine) from the Marcellus shale are analyzed to verify that our lab simulations mirror real-life conditions and results.

Submarine slope failures due to pipe structure formation.

PubMed

Elger, Judith; Berndt, Christian; Rüpke, Lars; Krastel, Sebastian; Gross, Felix; Geissler, Wolfram H

2018-02-19

There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.

Impacts of Natural Surfactant Soybean Phospholipid on Wettability of High-rank Coal Reservoir

NASA Astrophysics Data System (ADS)

Lyu, S.; Xiao, Y.; Yuan, M.; Wang, S.

2017-12-01

It is significant to change the surface wettability of coal rock with the surfactant in coal mining and coalbed methane exploitation. Soybean phospholipid (SP) is a kind of natural zwitterionic surfactant which is non-toxic and degradable. In order to study the effects of soybean phospholipid on wettability of high-rank coal in Qinshui Basin, some experiments including surface tension test, contact angle measurement on the coal surface, coal fines imbibition, observation of dispersion effect and gas permeability test were carried out, and water locking mechanism of fracturing fluid in micro fractures of coal reservoir was analyzed. The results show that the surface of high-rank coal was negatively charged in solution and of weak hydrophilicity. The soybean phospholipid with the mass fraction of 0.1% reduced the surface tension of water by 69%, and increased the wettability of coal. Meanwhile, the soybean phospholipid helped coal fines to disperse by observation of the filter cake with the scanning electron microscope. The rising rate of soybean phospholipid solution in the pipe filled with coal fines was lower than that of anionic and cationic surfactant, higher than that of clean water and non-ionic surfactant. Composite surfactant made up of soybean phospholipid and OP-10 at the ratio of 1:3 having a low surface tension and large contact angle, reduced the capillary force effectively, which could be conducive to discharge of fracturing fluid from coal reservoir micro fracture and improve the migration channels of gas. Therefore it has a broad application prospect.

Karst-on-a-chip: microfluidic studies of dissolution of a gypsum fracture

NASA Astrophysics Data System (ADS)

Szymczak, Piotr; Dutka, Filip; Osselin, Florian

2017-04-01

Dissolution of fractured and porous media introduces a positive feedback between fluid transport and chemical reactions at mineral surfaces leading to self-focusing of the flow in pronounced wormhole-like channels [1,2]. We study the flow-induced dissolution in a simple microfluidic setup, with a gypsum block inserted in between two polycarbonate plates, which is the simplest model of a fracture [3]. This gives us a unique opportunity to observe the evolution of the dissolution patterns in-situ and in real-time. By changing the flow rate and the aperture of the fracture we can scan a relatively wide range of Peclet and Damkohler numbers, characterizing the relative magnitude of advection, diffusion and reaction in the system. Additionally, as the aperture is increased, a transition is observed between the fractal and regular dissolution patterns. For small gaps, the patterns are ramified fractals. For larger gaps, the dissolution fingers are found to have regular forms of two different kinds: either linear (for high flow rates) or parabolic (for lower flow rates). The experiments are supplemented with numerical simulations and analytical modeling which allow for a better understanding of evolving flow patterns. In particular, we find the shapes and propagation velocities of dominant fingers for different widths of the system, flow rates and reaction rates. Finally, we comment on the link between the experimentally observed patterns and the natural karst systems - both cave conduits and epikarst solution pipes. [1] Hoefner, M. L. and Fogler, H. S. Pore evolution and channel formation during flow and reaction in porous media. AIChE J. 34, 45-54, 1988 [2] P. Szymczak, A. J. C. Ladd, Wormhole formation in dissolving fractures, J. Geophys. Res., 114, B06203, 2009 [3] F. Osselin, P. Kondratiuk, A Budek, O. Cybulski, P. Garstecki, P. Szymczak Microfluidic observation of the onset of reactive infiltration instability in an analog fracture, Geophys. Res. Lett., 43, 6907-6915, 2016

Measuring the hydraulic fracture-induced deformation of reservoirs and adjacent rocks employing a deeply buried inclinometer array: GRI/DOE multi-site project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branagan, P.T.; Warpinski, N.R.; Engler, B.

A vertical inclinometer array consisting of six biaxial tiltmeters was cemented behind pipe at depths between 4,273 and 4,628 ft. This wide-aperture array provided real-time tilt profiles corresponding to a series of seven hydraulic fractures being conducted in a nearby offset well in a fluvial sandstone reservoir. Array profiles for three KCl water fracs indicated that height growth was confined to the gross thickness of the reservoir despite extensive fracture length extension. Long-term monitoring of the array suggests that a substantial residual frac: width remained long after fracture closure occurred. For two 400-bbl linear gel minifracs, some height growth wasmore » observed but it was not extensive. Tilt amplitudes related to expanded frac widths were found to increase as would be expected with these thicker frac fluids. When cross-linker and proppant were included in the last fracture, tilt-derived heights were seen to grow rapidly extending into the bounding layers as the more complex fluids entered the fracture system. This inclinometer array was one of several independent, yet complimentary, fracture diagnostics tools that included crosswell multilevel microseismic arrays, FRACPRO{reg_sign} and a remote fracture intersection well. Their purpose was to provide integrated field-scale data regarding hydraulic fracture dynamics and geometry that would be used to construct accurate fracture mapping and diagnostic techniques.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, T.; Kameyama, M.; Urabe, Y.

At present, cast duplex stainless steel has been used for the primary coolant piping of PWRs in Japan and joints of dissimilar material have been applied for welding to reactor vessels and steam generators. For the primary coolant piping of the next APWR plants, application of low alloy steel that results in designing main loops with the same material is being studied. It means that there is no need to weld low alloy steel with stainless steel and that makes it possible to reduce the welding length. Attenuation of Ultra Sonic Wave Intensity is lower for low alloy steel thanmore » for stainless steel and they have advantageous inspection characteristics. In addition to that, the thermal expansion rate is smaller for low alloy steel than for stainless steel. In consideration of the above features of low alloy steel, the overall reliability of primary coolant piping is expected to be improved. Therefore, for the evaluation of crack stability of low alloy steel piping to be applied for primary loops, elastic-plastic future mechanics analysis was performed by means of a three-dimensioned FEM. The evaluation results for the low alloy steel pipings show that cracks will not grow into unstable fractures under maximum design load conditions, even when such a circumferential crack is assumed to be 6 times the size of the wall thickness.« less

Diatremes and craters attributed to natural explosions

USGS Publications Warehouse

Shoemaker, Eugene Merle

1956-01-01

Diatremes - volcanic pipes attributed to explosion - and craters have been studied to infer the ultimate causes and physical conditions attending natural explosive processes. Initial piercement of diatremes on the Navajo reservation, Arizona was probably along a fracture propagated by a high-pressure aqueous fluid. Gas rising at high velocity along the fracture would become converted to a gas-solid fluidized system by entrainment of wall- rock fragments. The first stages of widening of the vent are probably accomplished mainly by simple abrasion of the high-velocity fluidized system on the walls of the fracture. As the vent widens, its enlargement may be accelerated by inward spalling of the walls. The inferred mechanics of the Navajo-Hopi diatremes is used to illustrate the possibility of diatreme formation over a molten salt mass.

Experimenting with a "Pipe" Whistle

ERIC Educational Resources Information Center

Stafford, Olga

2012-01-01

A simple pipe whistle can be made using pieces of PVC pipe. The whistle can be used to measure the resonant frequencies of open or closed pipes. A slightly modified version of the device can be used to also investigate the interesting dependence of the sound frequencies produced on the orifice-to-edge distance. The pipe whistle described here…

Finding buried metallic pipes using a non-destructive approach based on 3D time-domain induced polarization data

NASA Astrophysics Data System (ADS)

Shao, Zhenlu; Revil, André; Mao, Deqiang; Wang, Deming

2018-04-01

The location of buried utility pipes is often unknown. We use the time-domain induced polarization method to non-intrusively localize metallic pipes. A new approach, based on injecting a primary electrical current between a pair of electrodes and measuring the time-lapse voltage response on a set of potential electrodes after shutting down this primary current is used. The secondary voltage is measured on all the electrodes with respect to a single electrode used as a reference for the electrical potential, in a way similar to a self-potential time lapse survey. This secondary voltage is due to the formation of a secondary current density in the ground associated with the polarization of the metallic pipes. An algorithm is designed to localize the metallic object using the secondary voltage distribution by performing a tomography of the secondary source current density associated with the polarization of the pipes. This algorithm is first benchmarked on a synthetic case. Then, two laboratory sandbox experiments are performed with buried metallic pipes located in a sandbox filled with some clean sand. In Experiment #1, we use a horizontal copper pipe while in Experiment #2 we use an inclined stainless steel pipe. The result shows that the method is effective in localizing these two pipes. At the opposite, electrical resistivity tomography is not effective in localizing the pipes because they may appear resistive at low frequencies. This is due to the polarization of the metallic pipes which blocks the charge carriers at its external boundaries.

Comparative Investigation and Operational Performance Characteristics of a Wick Assisted and Axially Square Grooved Heat Pipe

NASA Astrophysics Data System (ADS)

Naik, Rudra, Dr.; Rama Narasihma, K., Dr.; Anikivi, Atmanand

2018-04-01

The present work reported here involves the experimental investigation and performance evaluation of wick assisted and axially square grooved heat pipes of outer diameter 8mm, inner diameter 4mm with a length of 150mm.The objective of this work is to design, fabricate and test the heat pipes with and without an axial square groove for horizontal and gravity assisted conditions. The performance of the heat pipes was measured in terms of thermal resistance and heat transfer coefficients. In the present investigation four different working fluids were chosen namely acetone, ethanol, methanol and distilled water. Experiments were conducted by varying the heat load from 2 W to 10 W for different fill charge ratios in the range of 25% to 75% of evaporator volume for wick assisted heat pipe and 8 W to 18 W for axially square grooved heat pipe. From the experiments, it was found that there is a steady increase in temperature with the increase in heat input. The overall heat transfer coefficient was found to increase with the increase heat load for wick assisted heat pipe. In case of axially square grooved heat pipe, an attempt was made to experiment the heat pipe in different orientations. The maximum heat transfer coefficient of 7000 W/m2 °C is found for Acetone at 180° orientation.

Scaling of an Optically Pumped Mid-Infrared Rubidium Laser

DTIC Science & Technology

2015-03-26

v AFIT-ENP-MS-15-M-104 Abstract An optically pumped mid-infrared rubidium (Rb) pulsed laser has been demonstrated in a heat pipe ... Heat Pipe Assembly ........................................................................................12 Figure 3.3. Rb Number Density vs. Heat ...the first experiments that used a heat pipe as the gain cell. This experiment would influence the work of Sharma (Sharma, 1981:210). 9 Krupke

[Study on pipe material's influence on chlorine dioxide drinking water disinfection].

PubMed

He, Tao; Yue, Yinling; Ling, Bo; Zhang, Lan

2010-09-01

To study the pipe material's influence on chlorine dioxide drinking water disinfection. 0.8 mg/L chlorine dioxide solution was injected into 5 kinds of pipes respectively, PPR, PVC-U, Steel with Zinc coating, copper and PE pipes. Dipped free from light for 48 hours and the concentrations of chlorine dioxide, chlorite and chlorate were tested from samples taken from each kind of pipe at 1, 2, 3, 4, 5, 6, 12, 24 and 48 hours respectively. Chlorine dioxides decay rates in the water dipping the pipes increase as the dipping time increases and the decay of chlorine dioxide mainly occurs within 6 hours after the dipping. But for different pipe, the influence of decay differs. The consumption of chlorine dioxide of the metal pipes is more than that of the plastic pipes. And with 2 hours after the dipping experiment begins, the concentrations of the chlorite of the copper pipe and of the steel with zinc coating pipe increase quickly and reach the maximum concentration. But then the chlorite concentration decreases greatly. After dipped 24 hours, the chlorite in the water in the pipe can not be detected. For other plastic piples, all the chlorite concentrations in the dipping water increase as the dipping time increase. Compared with the start of the dipping experiment, the chlorate concentration in the dipping water of each pipe has no obvious change. The material of the water transportation pipe does have influence on chlorine dioxide drinking water disinfection.

Catalog of Audiovisual Productions. Volume 2. Navy and Marine Corps Productions

DTIC Science & Technology

1984-06-01

O" - _ BEPEFITS IILITMAY S/06 BOISII P/2BETA ARICLES T/06 BONDING, CHEMICAL T/02 RETATROS T/06 BONE... FRACTURES C/02.21 C/E0AES 5 BONES (HUIAN) C...H/O1 ..... ’ *b-]1 FIR , M IC 03 FLOOD cUro F104 FIELDS, LDING 02 FLUIDS HYDRALIC J/07 FIELDS lI C /03 FLM kENT LIGhTS F/02 FAT ’ AliAFT /03.3 FLYING...PIPE Ff11 FGRIS, CRYSTALLINE T/09 FLAX JACKETS ,M/08 FORMULA$ K/0! 1- FLAKE THROWERS R/01 FRACTOGRAPHY (MATERIALS) J/05 FLAETIHROWERS R/01 FRACTURES

Evaluation of Neutron Elastic Scatter (NES) technique for detection of graphitic corrosion in gas cast iron pipe. Final report, March 1996-April 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charatis, G.; Hugg, E.; McEllistrem, M.

1997-04-01

PENETRON, Inc., in two phases, demonstrated the effectiveness of its Neutron elastic Scatter (NES) techniques in detecting the change in the carbon weight percentage (CWt%) as a measure of corrosion in gray cast iron pipe. In Phase I, experiments were performed with synthetic standards supplied by IIT Research Institute (IITRI) to test the applicability of the NES techniques. Irradiation experiments performed at the University of Kentucky showed that CWt% could be detected, ranging from 1.6% to 13%, within an uncertainty of around 4%. In Phase II, experiments were performed on seven (7) corroded pipe sections supplied by MichCon. Tests weremore » made on pipe sliced lengthwise into quarter sections, and in re-assembled whole pipe sections. X-ray films of the quarter sections indicated probable areas of corrosion for each quarter section.« less

Physical Properties of Granulates Used in Analogue Experiments of Caprock Failure and Sediment Remobilisation

NASA Astrophysics Data System (ADS)

Kukowski, N.; Warsitzka, M.; May, F.

2014-12-01

Geological systems consisting of a porous reservoir and a low-permeable caprock are prone to hydraulic fracturing, if pore pressure rises to the effective stress. Under certain conditions, hydraulic fracturing is associated with sediment remobilisation, e.g. sand injections or pipes, leading to reduced seal capacity of the caprock. In dynamically scaled analogue experiments using granular materials and air pressure, we intent to investigate strain patterns and deformation mechanisms during caprock failure and fluidisation of shallow over-pressured reservoirs. The aim of this study is to improve the understanding of leakage potential of a sealing formation and the fluidisation potential of a reservoir formation depending on rock properties and effective stress. For reliable interpretation of analogue experiments, physical properties of analogue materials, e.g. frictional strength, cohesion, density, permeability etc., have to be correctly scaled according to those of their natural equivalents. The simulation of caprock requires that the analogue material possess a low permeability and is capable to shear failure and tensional failure. In contrast, materials representing the reservoir have to possess high porosity and low shear strength. In order to find suitable analogue materials, we measured the stress-strain behaviour and the permeability of over 25 different types of natural and artificial granular materials, e.g. glass powder, siliceous microspheres, diatomite powder, loess, or plastic granulate. Here, we present data of frictional parameters, compressibility and permeability of these granular materials characterized as a function of sphericity, grain size, and density. The repertoire of different types of granulates facilitates the adjustment of accurate mechanical properties in the analogue experiments. Furthermore, conditions during seal failure and fluidisation can be examined depending on the wide range of varying physical properties.

The locating ways of laying pipe manipulator

NASA Astrophysics Data System (ADS)

Wang, Dan; Li, Bin; Lei, DongLiang

2010-01-01

The laying pipe manipulator is a new equipment to lay concrete pipe. This kind of manipulator makes the work of laying pipes mechanized and automated. We report here a new laying pipe manipulator. The manipulator has 5 free degrees, and is driven by the hydraulic system. In the paper, one critical question of manipulator is studied: the locating ways of the manipulator to lay concrete pipe. During the process of laying concrete pipe, how to locate the manipulator is realized by the locating system of manipulator. The locating system consists of photoelectric target, laser producer, and computer. According to different construction condition, one or two or three photoelectric targets can be used. During the process of laying concrete pipe, if the interface of pipes are jointed together, and the other segment of pipe deviates from the pipe way, one target can be used, if the angle that the manipulator rotates around the holding pipe's axes is 0°, two targets can be used, three targets can be used at any site. In the paper, according to each locating way, the theory analysis is done. And the mathematical models of the manipulator moving from original position to goal position are obtained by different locating way. And the locating experiment was done. According to the experiment result, the work principle and mathematical models of different locating way was turned out to be well adopted for requirement, the mathematical model of different locating way supplies the basic control theory for the manipulator to lay and joint concrete pipe automatically.

Investigation of growth features in several hydraulic fractures

NASA Astrophysics Data System (ADS)

Bykov, Alexander; Galybin, Alexander; Evdokimov, Alexander; Zavialova, Natalia; Zavialov, Ivan; Negodiaev, Sergey; Perepechkin, Ilia

2017-04-01

In this paper we simulate the growth of three or more interacting hydraulic fractures in the horizontal well with a cross flow of fluid between them. Calculation of the dynamics of cracks is performed in three dimensional space. The computation of the movement of fracturing fluid with proppant is performed in the two-dimensional space (the flow was averaged along crack aperture). For determining the hydraulic pipe resistance coefficient we used a generalization of the Reynolds number for fluids with power rheology and a generalization of the von Karman equation made by Dodge and Meiner. The calculations showed that the first crack was developing faster than the rest in homogeneous medium. During the steady loading the outer cracks pinch the inner cracks and it was shown that only the first and last fracture develop in extreme case. It is also possible to simulate the parameters at which the two developing outer cracks pinch the central one in the horizontal direction. In this case, the central crack may grow in the vertical direction.

The Relationship Between Constraint and Ductile Fracture Initiation as Defined by Micromechanical Analyses

NASA Technical Reports Server (NTRS)

Panontin, Tina L.; Sheppard, Sheri D.

1994-01-01

The use of small laboratory specimens to predict the integrity of large, complex structures relies on the validity of single parameter fracture mechanics. Unfortunately, the constraint loss associated with large scale yielding, whether in a laboratory specimen because of its small size or in a structure because it contains shallow flaws loaded in tension, can cause the breakdown of classical fracture mechanics and the loss of transferability of critical, global fracture parameters. Although the issue of constraint loss can be eliminated by testing actual structural configurations, such an approach can be prohibitively costly. Hence, a methodology that can correct global fracture parameters for constraint effects is desirable. This research uses micromechanical analyses to define the relationship between global, ductile fracture initiation parameters and constraint in two specimen geometries (SECT and SECB with varying a/w ratios) and one structural geometry (circumferentially cracked pipe). Two local fracture criteria corresponding to ductile fracture micromechanisms are evaluated: a constraint-modified, critical strain criterion for void coalescence proposed by Hancock and Cowling and a critical void ratio criterion for void growth based on the Rice and Tracey model. Crack initiation is assumed to occur when the critical value in each case is reached over some critical length. The primary material of interest is A516-70, a high-hardening pressure vessel steel sensitive to constraint; however, a low-hardening structural steel that is less sensitive to constraint is also being studied. Critical values of local fracture parameters are obtained by numerical analysis and experimental testing of circumferentially notched tensile specimens of varying constraint (e.g., notch radius). These parameters are then used in conjunction with large strain, large deformation, two- and three-dimensional finite element analyses of the geometries listed above to predict crack initiation loads and to calculate the associated (critical) global fracture parameters. The loads are verified experimentally, and microscopy is used to measure pre-crack length, crack tip opening displacement (CTOD), and the amount of stable crack growth. Results for A516-70 steel indicate that the constraint-modified, critical strain criterion with a critical length approximately equal to the grain size (0.0025 inch) provides accurate predictions of crack initiation. The critical void growth criterion is shown to considerably underpredict crack initiation loads with the same critical length. The relationship between the critical value of the J-integral for ductile crack initiation and crack depth for SECT and SECB specimens has been determined using the constraint-modified, critical strain criterion, demonstrating that this micromechanical model can be used to correct in-plane constraint effects due to crack depth and bending vs. tension loading. Finally, the relationship developed for the SECT specimens is used to predict the behavior of circumferentially cracked pipe specimens.

Long Duration Exposure Facility (LDEF) low temperature Heat Pipe Experiment Package (HEPP) flight results

NASA Technical Reports Server (NTRS)

Mcintosh, Roy; Mccreight, Craig; Brennan, Patrick J.

1993-01-01

The Low Temperature Heat Pipe Flight Experiment (HEPP) is a fairly complicated thermal control experiment that was designed to evaluate the performance of two different low temperature ethane heat pipes and a low-temperature (182 K) phase change material. A total of 390 days of continuous operation with an axially grooved aluminum fixed conductance heat pipe and an axially grooved stainless steel heat pipe diode was demonstrated before the data acquisition system's batteries lost power. Each heat pipe had approximately 1 watt applied throughout this period. The HEPP was not able to cool below 188.6 K during the mission. As a result, the preprogrammed transport test sequence which initiates when the PCM temperature drops below 180 K was never exercised, and transport tests with both pipes and the diode reverse mode test could not be run in flight. Also, because the melt temperature of the n-heptane PCM is 182 K, its freeze/thaw behavior could not be tested. Post-flight thermal vacuum tests and thermal analyses have indicated that there was an apparent error in the original thermal analyses that led to this unfortunate result. Post-flight tests have demonstrated that the performance of both heat pipes and the PCM has not changed since being fabricated more than 14 years ago. A summary of HEPP's flight data and post-flight test results are presented.

Control of Microstructures and the Practical Properties of API X80 Grade Heavy-Wall High-Frequency Electric Resistance-Welded Pipe with Excellent Low-Temperature Toughness

NASA Astrophysics Data System (ADS)

Goto, Sota; Nakata, Hiroshi; Toyoda, Shunsuke; Okabe, Takatoshi; Inoue, Tomohiro

2017-10-01

This paper describes development of heavy-walled API X80 grade high-frequency electric resistance-welded (HFW) line pipes and conductor-casing pipes with wall thicknesses up to 20.6 mm. A fine bainitic-ferrite microstructure, which is preferable for low-temperature toughness, was obtained by optimizing the carbon content and applying the thermomechanical controlled hot-rolling process. As a result, the Charpy ductile-brittle transition temperature (DBTT) was well below 227 K (-46 °C) in the base metal of the HFW line pipe. When the controlled hot-rolling ratio (CR) was increased from 23 to 48 pct, the area average grain size decreased from 15 to 8 μm. The dependence of CTOD properties on CR was caused by the largest grain which is represented by the area average grain size. No texture development due to the increase of CR from 23 to 48 pct was observed. In addition, because controlled in-line heat treatment of the longitudinal weld seam also produced the fine bainitic-ferrite microstructure at the weld seam, DBTT was lower than 227 K (-46 °C) at the weld portion. The developed pipes showed good girth weldability without preheat treatment, and fracture in the tensile test initiated from the base metal in all cases.

Discussion on the solar concentrating thermoelectric generation using micro-channel heat pipe array

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Feng, Wei; Jin, Yi; Chen, Xiao; Ji, Jie

2017-11-01

Heat pipe is a high efficient tool in solar energy applications. In this paper, a novel solar concentrating thermoelectric generation using micro-channel heat pipe array (STEG-MCHP) was presented. The flat-plate micro-channel heat pipe array not only has a higher heat transfer performance than the common heat pipe, but also can be placed on the surface of TEG closely, which can further reduce the thermal resistance between the heat pipe and the TEG. A preliminary comparison experiment was also conducted to indicate the advantages of the STEG-MCHP. The optimization based on the model verified by the experiment was demonstrated, and the concentration ratio and selective absorbing coating area were also discussed. In addition, the cost analysis was also performed to compare between the STEG-MCHP and the common solar concentrating TEGs in series. The outcome showed that the solar concentrating thermoelectric generation using micro-channel heat pipe array has the higher electrical efficiency and lower cost, which may provide a suitable way for solar TEG applications.

Long Valley Deep Hole Geophysical Observatory --- Strain Instrumentation and Installation.

NASA Astrophysics Data System (ADS)

Sacks, S. I.; Linde, A.; Malin, P.; Roeloffs, E. A.; Hill, D. P.; Ellsworth, W. L.

2003-12-01

The Long Valley Exploratory Well, drilled in the middle of the resurgent dome in the Long Valley caldera, was started in 1989 and after rather checkered progress eventually reached a depth of about 9,831 feet. The hole is cased to a depth of 7178 feet with bare rock below that. At 8,500 feet there is an open fracture system with substantial permeability. One of the goals of the instrument installation is to enable monitoring of this deep aquifer. The most satisfactory rock away from obvious large fractures was at about 7,400 feet, and this was the installation depth. The instrumentation package consisted of a bottom hole seismometer at a depth of about 8500 feet, and a coupled instrument string that was cemented to the rock at a depth of 7400 feet. The instrument string, 73 feet long, had an inflatable packer with an extension at the bottom, coupled to a seismometer with a cement exit port above it, a 22 foot long spacing tube connected to a 20 foot long sensing volume strainmeter assembly. The strainmeter unit is essentially an annulus with the cementing pipe passing through it. In addition, two seismometer cables, two water bypass tubes and a packer inflation tube, pass through the strainmeter, which is actually two concentric strainmeters. The outer unit is a dilatometer and the inner unit is a vertical component strainmeter. Before installation, the strainmeters and the 8000 foot long stainless steel coupling tubes were filled with filtered and degassed water. The instrument string and attached bottom hole seismometer were then lowered down the hole attached to drill pipe. Two optical fiber vertical strainmeters (one interferometer and one time-of-flight loop) consisting of three fibers were attached to the drill pipe as it was installed. After the drill pipe reached target depth, it was secured to the well head. The packer, at the bottom of the instrument package, was inflated, thus providing a sealed bottom for the cement. Cement was then pumped down the drill pipe, through the strainmeter assembly and out the tube about 25 feet below the bottom of the strain sensing assembly. About 450 feet of the hole was cemented, the cement going into the casing. The coupling tubes from the strainmeters were connected to a surface mounted sensing head that had hydraulic amplification and electronic transducers. Pressure changes in the lower aquifer cause flow through two 1/4 inch diameter tubes into the annulus outside the mounting and cementing pipe. An opening sleeve in the installed pipe will allow the resulting water level changes to be monitored in a protected environment. All installed instrumentation seems to be functioning satisfactorily.

Technical reference for the use of the slow crack growth test for modeling and predicting the long-term performance of polyethylene gas pipes. Final report, March 1987-May 1992. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanninen, M.F.; O'Donoghue, P.E.; Popelar, C.F.

1993-02-01

The project was undertaken for the purposes of quantifying the Battelle slow crack growth (SCG) test for predicting long-term performance of polyethylene gas distribution pipes, and of demonstrating the applicability of the methodology for use by the gas industry for accelerated characterization testing, thereby bringing the SCG test development effort to a closure. The work has revealed that the Battelle SCG test, and the linear fracture mechanics interpretation that it currently utilizes, is valid for a class of PE materials. The long-term performance of these materials in various operating conditions can therefore be effectively predicted.

A thin gold coated hydrogen heat pipe-cryogenic target for external experiments at COSY

NASA Astrophysics Data System (ADS)

Abdel-Bary, M.; Abdel-Samad, S.; Elawadi, G. A.; Kilian, K.; Ritman, J.

2009-05-01

A gravity assisted Gold coated heat pipe (GCHP) with 5-mm diameter has been developed and tested to cool a liquid hydrogen target for external beam experiments at COSY. The need for a narrow target diameter leads us to study the effect of reducing the heat pipe diameter to 5 mm instead of 7 mm, to study the effect of coating the external surface of the heat pipe by a shiny gold layer (to decrease the radiation heat load), and to study the effect of using the heat pipe without using 20 layers of' super-insulation around it (aluminized Mylar foil) to keep the target diameter as small as possible. The developed gold coated heat pipe was tested with 20 layers of super-insulation (WI) and without super-insulation (WOI). The operating characteristics for both conditions were compared to show the advantages and disadvantages.

TSTA Piping and Flame Arrestor Operating Experience Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadwallader, Lee C.; Willms, R. Scott

The Tritium Systems Test Assembly (TSTA) was a facility dedicated to tritium handling technology and experiment research at the Los Alamos National Laboratory. The facility operated from 1984 to 2001, running a prototype fusion fuel processing loop with ~100 grams of tritium as well as small experiments. There have been several operating experience reports written on this facility’s operation and maintenance experience. This paper describes analysis of two additional components from TSTA, small diameter gas piping that handled small amounts of tritium in a nitrogen carrier gas, and the flame arrestor used in this piping system. The operating experiences andmore » the component failure rates for these components are discussed in this paper. Comparison data from other applications are also presented.« less

GIS based location optimization for mobile produced water treatment facilities in shale gas operations

NASA Astrophysics Data System (ADS)

Kitwadkar, Amol Hanmant

Over 60% of the nation's total energy is supplied by oil and natural gas together and this demand for energy will continue to grow in the future (Radler et al. 2012). The growing demand is pushing the exploration and exploitation of onshore oil and natural gas reservoirs. Hydraulic fracturing has proven to not only create jobs and achieve economic growth, but also has proven to exert a lot of stress on natural resources---such as water. As water is one of the most important factors in the world of hydraulic fracturing, proper fluids management during the development of a field of operation is perhaps the key element to address a lot of these issues. Almost 30% of the water used during hydraulic fracturing comes out of the well in the form of flowback water during the first month after the well is fractured (Bai et. al. 2012). Handling this large amount of water coming out of the newly fractured wells is one of the major issues as the volume of the water after this period drops off and remains constant for a long time (Bai et. al. 2012) and permanent facilities can be constructed to take care of the water over a longer period. This paper illustrates development of a GIS based tool for optimizing the location of a mobile produced water treatment facility while development is still occurring. A methodology was developed based on a multi criteria decision analysis (MCDA) to optimize the location of the mobile treatment facilities. The criteria for MCDA include well density, ease of access (from roads considering truck hauls) and piping minimization if piping is used and water volume produced. The area of study is 72 square miles east of Greeley, CO in the Wattenberg Field in northeastern Colorado that will be developed for oil and gas production starting in the year 2014. A quarterly analysis is done so that we can observe the effect of future development plans and current circumstances on the location as we move from quarter to quarter. This will help the operators to make long-term decisions and also they can make decisions about the well pad siting and well densities. Three different scenarios---baseline, retroactive and proactive---were considered to see what could be the proper way to answer the question of optimal fluids management (OFM). Once the locations were obtained the results from different scenarios were compared for piping distances from each well going towards the facility, assuming the pipeline distance as the criteria to be minimized. The results obtained were pretty robust and observed to be fulfilling the intended purpose.

Thermion: Verification of a thermionic heat pipe in microgravity

NASA Technical Reports Server (NTRS)

1991-01-01

The design and development is examined of a small excore heat pipe thermionic space nuclear reactor power system (SEHPTR). The need was identified for an in-space flight demonstration of a solar powered, thermionic heat pipe element. A demonstration would examine its performance and verify its operation in microgravity. The design of a microsatellite based technology demonstration experiment is proposed to measure the effects of microgravity on the performance of an integrated thermionic heat pipe device in low earth orbit. The specific objectives are to verify the operation of the liquid metal heat pipe and the cesium reservior in the space environment. Two design configurations are described; THERMION-I and THERMION-II. THERMION-I is designed for a long lifetime study of the operations of the thermionic heat pipe element in low earth orbit. Heat input to the element is furnished by a large mirror which collects solar energy and focuses it into a cavity containing the heat pipe device. THERMION-II is a much simpler device which is used for short term operation. This experiment remains attached to the Delta II second stage and uses energy from 500 lb of alkaline batteries to supply heat energy to the heat pipe device.

Laboratory exercises on oscillation modes of pipes

NASA Astrophysics Data System (ADS)

Haeberli, Willy

2009-03-01

This paper describes an improved lab setup to study the vibrations of air columns in pipes. Features of the setup include transparent pipes which reveal the position of a movable microphone inside the pipe; excitation of pipe modes with a miniature microphone placed to allow access to the microphone stem for open, closed, or conical pipes; and sound insulation to avoid interference between different setups in a student lab. The suggested experiments on the modes of open, closed, and conical pipes, the transient response of a pipe, and the effect of pipe diameter are suitable for introductory physics laboratories, including laboratories for nonscience majors and music students, and for more advanced undergraduate laboratories. For honors students or for advanced laboratory exercises, the quantitative relation between the resonance width and damping time constant is of interest.

Effect of Groove Design and Post-Weld Heat Treatment on Microstructure and Mechanical Properties of P91 Steel Weld

NASA Astrophysics Data System (ADS)

Pandey, C.; Mahapatra, M. M.

2016-07-01

The martensitic creep-resistant steel designated as ASTM A335 for plate and as P91 for pipe is primarily used for high-temperature and high-pressure applications in steam power plants due to its excellent high-temperature properties such as high creep strength, high thermal conductivity, low thermal expansion, and so on. However, in the case of welded joints of such steels, the presence of an inter-critical heat-affected zone (IC-HAZ) can cause the joint to have lower creep strength than the base metal. In the present study, the effect of post-welding heat treatment (PWHT) and weld groove designs on the overall microstructure and mechanical properties of P91 steel pipe welds produced by the gas tungsten arc welding process was studied. Various regions of welded joints were characterized in detail for hardness and metallographic and tensile properties. Sub-size tensile samples were also tested to evaluate the mechanical properties of the weld metal and heat-affected zone (HAZ) with respect to PWHT. After PWHT, a homogenous microstructure was observed in the HAZ and tensile test fracture samples revealed shifting of the fracture location from the IC-HAZ to the fine-grained heat-affected zone. Before PWHT, the conventional V-grooved welded joints exhibited higher tensile strength compared to the narrow-grooved joints. However, after PWHT, both narrow- and V-grooved joints exhibited similar strength. Fractography of the samples indicates the presence of carbide precipitates such as Cr23C6, VC, and NbC on the fracture surface.

TRACER DISPERSION STUDIES FOR HYDRAULIC CHARACTERIZATION OF PIPES

EPA Science Inventory

A series of experiments were conducted at the U. S. Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, Ohio, to quantify longitudinal dispersion of a sodium fluoride tracer in polyvinyl chloride (PVC) pipe and ductile iron pipe under laminar, tr...

Visualization of Flow in Pressurizer Spray Line Piping and Estimation of Thermal Stress Fluctuation Caused by Swaying of Water Surface

NASA Astrophysics Data System (ADS)

Oumaya, Toru; Nakamura, Akira; Onojima, Daisuke; Takenaka, Nobuyuki

The pressurizer spray line of PWR plants cools reactor coolant by injecting water into pressurizer. Since the continuous spray flow rate during commercial operation of the plant is considered insufficient to fill the pipe completely, there is a concern that a water surface exists in the pipe and may periodically sway. In order to identify the flow regimes in spray line piping and assess their impact on pipe structure, a flow visualization experiment was conducted. In the experiment, air was used substituted for steam to simulate the gas phase of the pressurizer, and the flow instability causing swaying without condensation was investigated. With a full-scale mock-up made of acrylic, flow under room temperature and atmospheric pressure conditions was visualized, and possible flow regimes were identified based on the results of the experiment. Three representative patterns of swaying of water surface were assumed, and the range of thermal stress fluctuation, when the surface swayed instantaneously, was calculated. With the three patterns of swaying assumed based on the visualization experiment, it was confirmed that the thermal stress amplitude would not exceed the fatigue endurance limit prescribed in the Japanese Design and Construction Code.

Weld residual stresses and plastic deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybicki, E.; Shiratori, M.

1989-01-01

Residual stresses due to welding can play a primary role in the performance of piping systems and pressure vessels. The stresses are high, in the range of the yield stress of the material, and can influence the fatigue and fracture behavior as well as component service life. Thus, it is important to have an understanding of weld residual stresses. The papers in this section address the important topic of residual stresses and failure analysis. The paper by Boyles reviews computer simulation in the prediction and analysis of fatigue, fracture, and creep of welded structures. The growing use of expert systemsmore » for these purposes is also covered. Karisson, et al, determine the deformations and stresses during the butt-welding of a pipe. The determination of residual deformations and stresses is also presented. Oddy, Goldak, and McDill propose a method to incorporate transformation plasticity in a finite element program. A three-dimensional analysis of a short longitudinal pipe weld in a typical pressure vessel steel is presented. Chaaban, Morin, Ma, and Bazergui study the influence of ligament thickness, strain hardening, expansion sequence, and level of applied expansion pressure on the interference fit in a model of a tube-to-tubesheet joint in a heat exchanger. This section contains papers dealing with models for plastic deformation. Imatani, Teraura, and Inoue formulate a viscoplastic constitutive model based on an anisotropic yield criterion. Comparisons with experimental results obtained using thin walled tubular specimens made from SUS 304 stainless steel show that the present yield criterion adequately accounts for prior deformation history. Niitsu, Horiguchi, and Ikegami investigate the plastic behavior of S25C mild steel tubular specimens subjected to combined axial and torsional loading at both constant and variable temperatures.« less

Geochemical soil sampling for deeply-buried mineralized breccia pipes, northwestern Arizona

USGS Publications Warehouse

Wenrich, K.J.; Aumente-Modreski, R. M.

1994-01-01

Thousands of solution-collapse breccia pipes crop out in the canyons and on the plateaus of northwestern Arizona; some host high-grade uranium deposits. The mineralized pipes are enriched in Ag, As, Ba, Co, Cu, Mo, Ni, Pb, Sb, Se, V and Zn. These breccia pipes formed as sedimentary strata collapsed into solution caverns within the underlying Mississippian Redwall Limestone. A typical pipe is approximately 100 m (300 ft) in diameter and extends upward from the Redwall Limestone as much as 1000 m (3000 ft). Unmineralized gypsum and limestone collapses rooted in the Lower Permian Kaibab Limestone or Toroweap Formation also occur throughout this area. Hence, development of geochemical tools that can distinguish these unmineralized collapse structures, as well as unmineralized breccia pipes, from mineralized breccia pipes could significantly reduce drilling costs for these orebodies commonly buried 300-360 m (1000-1200 ft) below the plateau surface. Design and interpretation of soil sampling surveys over breccia pipes are plagued with several complications. (1) The plateau-capping Kaibab Limestone and Moenkopi Formation are made up of diverse lithologies. Thus, because different breccia pipes are capped by different lithologies, each pipe needs to be treated as a separate geochemical survey with its own background samples. (2) Ascertaining true background is difficult because of uncertainties in locations of poorly-exposed collapse cones and ring fracture zones that surround the pipes. Soil geochemical surveys were completed on 50 collapse structures, three of which are known mineralized breccia pipes. Each collapse structure was treated as an independent geochemical survey. Geochemical data from each collapse feature were plotted on single-element geochemical maps and processed by multivariate factor analysis. To contrast the results between geochemical surveys (collapse structures), a means of quantifying the anomalousness of elements at each site was developed. This degree of anomalousness, named the "correlation value", was used to rank collapse features by their potential to overlie a deeply-buried mineralized breccia pipe. Soil geochemical results from the three mineralized breccia pipes (the only three of the 50 that had previously been drilled) show that: (1) Soils above the SBF pipe contain significant enrichment of Ag, Al, As, Ba, Ga, K, La, Mo, Nd, Ni, Pb, Sc, Th, U and Zn, and depletion in Ca, Mg and Sr, in contrast to soils outside the topographic and structural rim; (2) Soils over the inner treeless zone of the Canyon pipe show Mo and Pb enrichment anf As and Ga depletion, in contrast to soils from the surrounding forest; and (3) The soil survey of the Mohawk Canyon pipe was a failure because of the rocky terrane and lack of a B soil horizon, or because the pipe plunges. At least 11 of the 47 other collapse structures studied contain anomalous soil enrichments similar to the SBF uranium ore-bearing pipe, and thus have good potential as exploration targets for uranium. One of these 11, #1102, does contain surface mineralized rock. These surveys suggest that soil geochemical sampling is a useful tool for the recognition of many collapse structures with underlying ore-bearing breccia pipes. ?? 1994.

Hydrogen accelerated fatigue crack growth of friction stir welded X52 steel pipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ronevich, Joseph Allen; Somerday, Brian P.; Feng, Zhili

Friction stir welded steel pipelines were tested in high pressure hydrogen gas to examine the effects of hydrogen accelerated fatigue crack growth. Fatigue crack growth rate (da/dN) vs. stress-intensity factor range (ΔK) relationships were measured for an X52 friction stir welded pipe tested in 21 MPa hydrogen gas at a frequency of 1 Hz and R = 0.5. Tests were performed on three regions: base metal (BM), center of friction stir weld (FSW), and 15 mm off-center of the weld. For all three material regions, tests in hydrogen exhibited accelerated fatigue crack growth rates that exceeded an order of magnitudemore » compared to companion tests in air. Among tests in hydrogen, fatigue crack growth rates were modestly higher in the FSW than the BM and 15 mm off-center tests. Select regions of the fracture surfaces associated with specified ΔK levels were examined which revealed intergranular fracture in the BM and 15 mm off-center specimens but an absence of intergranular features in the FSW specimens. In conclusion, the X52 friction stir weld and base metal tested in hydrogen exhibited fatigue crack growth rate relationships that are comparable to those for conventional arc welded steel pipeline of similar strength found in the literature.« less

Hydrogen accelerated fatigue crack growth of friction stir welded X52 steel pipe

DOE PAGES

Ronevich, Joseph Allen; Somerday, Brian P.; Feng, Zhili

2016-11-17

Friction stir welded steel pipelines were tested in high pressure hydrogen gas to examine the effects of hydrogen accelerated fatigue crack growth. Fatigue crack growth rate (da/dN) vs. stress-intensity factor range (ΔK) relationships were measured for an X52 friction stir welded pipe tested in 21 MPa hydrogen gas at a frequency of 1 Hz and R = 0.5. Tests were performed on three regions: base metal (BM), center of friction stir weld (FSW), and 15 mm off-center of the weld. For all three material regions, tests in hydrogen exhibited accelerated fatigue crack growth rates that exceeded an order of magnitudemore » compared to companion tests in air. Among tests in hydrogen, fatigue crack growth rates were modestly higher in the FSW than the BM and 15 mm off-center tests. Select regions of the fracture surfaces associated with specified ΔK levels were examined which revealed intergranular fracture in the BM and 15 mm off-center specimens but an absence of intergranular features in the FSW specimens. In conclusion, the X52 friction stir weld and base metal tested in hydrogen exhibited fatigue crack growth rate relationships that are comparable to those for conventional arc welded steel pipeline of similar strength found in the literature.« less

Strain corrosion cracking in rpm sewer piping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, S.W.; Wachob, H.F.; Duffner, D.H.

1993-12-31

Long term, aggressive environmental exposure can result in localized failure of large diameter, glass reinforced plastic mortar (RPM) piping. In order to evaluate the performance of the liner and glass reinforced matrix polyester resin, accelerated strain corrosion tests were performed on samples of RPM piping that had already experienced almost 15 years of service. To assess the sensitivity of RPM pipe to acidic environments and to correlate the fractography of the laboratory produced failures with the excavated crack, short segments of 8-inch and 48-inch diameter piping were statically loaded to produce various known surface strains. After preloading the specimens tomore » fixed strain levels, these samples were then exposed to sulfuric acid solutions having pH values of 2.7 and 4.7 and monitored as a function of time until failure. The resulting lifetimes were related to initial surface strains and showed a decreasing logarithmic relationship. Fractographic examination of the excavated crack revealed the typical strain corrosion fractography of glass fibers after almost a 1000 hour exposure at 1.3 % strain; similar fractographic observations were obtained from failed laboratory samples. At shorter times, failure appeared to be overload in nature and exhibited little, if any, timedependent fracture features. Fractographic examination of the excavated crack strongly indicated that the crack had been present for a significant time. The extremely aggressive environment had totally dissolved the exposed glass reinforcement. Based on the laboratory strain corrosion performance, the nature of the contained cracking, and fractography of the failed surface, cracking of the excavated RPM pipe was believed to be the result of an early overload failure that subsequently propagated slowly via strain corrosion in an extremely aggressive environment.« less

Depriming of arterial heat pipes: An investigation of CTS thermal excursions

NASA Technical Reports Server (NTRS)

Antoniuk, D.; Edwards, D. K.

1980-01-01

Four thermal excursions of the Transmitter Experiment Package (TEP) were the result of the depriming of the arteries in all three heat pipes in the Variable Conductance Heat Pipe System which cooled the TEP. The determined cause of the depriming of the heat pipes was the formation of bubbles of the nitrogen/helium control gas mixture in the arteries during the thaw portion of a freeze/thaw cycle of the inactive region of the condenser section of the heat pipe. Conditions such as suction freezeout or heat pipe turn-on, which moved these bubbles into the active region of the heat pipe, contributed to the depriming mechanism. Methods for precluding, or reducing the probability of, this type of failure mechanism in future applications of arterial heat pipes are included.

A Time-Variant Reliability Model for Copper Bending Pipe under Seawater-Active Corrosion Based on the Stochastic Degradation Process

PubMed Central

Li, Mengmeng; Feng, Qiang; Yang, Dezhen

2018-01-01

In the degradation process, the randomness and multiplicity of variables are difficult to describe by mathematical models. However, they are common in engineering and cannot be neglected, so it is necessary to study this issue in depth. In this paper, the copper bending pipe in seawater piping systems is taken as the analysis object, and the time-variant reliability is calculated by solving the interference of limit strength and maximum stress. We did degradation experiments and tensile experiments on copper material, and obtained the limit strength at each time. In addition, degradation experiments on copper bending pipe were done and the thickness at each time has been obtained, then the response of maximum stress was calculated by simulation. Further, with the help of one kind of Monte Carlo method we propose, the time-variant reliability of copper bending pipe was calculated based on the stochastic degradation process and interference theory. Compared with traditional methods and verified by maintenance records, the results show that the time-variant reliability model based on the stochastic degradation process proposed in this paper has better applicability in the reliability analysis, and it can be more convenient and accurate to predict the replacement cycle of copper bending pipe under seawater-active corrosion. PMID:29584695

Gas Pressure-Drop Experiment

ERIC Educational Resources Information Center

Luyben, William L.; Tuzla, Kemal

2010-01-01

Most chemical engineering undergraduate laboratories have fluid mechanics experiments in which pressure drops through pipes are measured over a range of Reynolds numbers. The standard fluid is liquid water, which is essentially incompressible. Since density is constant, pressure drop does not depend on the pressure in the pipe. In addition, flow…

The effect of advanced treatment on chlorine decay in metallic pipes

EPA Science Inventory

Experiments were run to measure what effect advanced treatment might have on the kinetics of chlorine decay in water distribution systems. A recirculating loop of 6-inch diameter unlined ductile iron pipe was used to simulate turbulent flow conditions in a pipe with significant c...

A quasi steady state method for solving transient Darcy flow in complex 3D fractured networks accounting for matrix to fracture flow

NASA Astrophysics Data System (ADS)

Nœtinger, B.

2015-02-01

Modeling natural Discrete Fracture Networks (DFN) receives more and more attention in applied geosciences, from oil and gas industry, to geothermal recovery and aquifer management. The fractures may be either natural, or artificial in case of well stimulation. Accounting for the flow inside the fracture network, and accounting for the transfers between the matrix and the fractures, with the same level of accuracy is an important issue for calibrating the well architecture and for setting up optimal resources recovery strategies. Recently, we proposed an original method allowing to model transient pressure diffusion in the fracture network only [1]. The matrix was assumed to be impervious. A systematic approximation scheme was built, allowing to model the initial DFN by a set of N unknowns located at each identified intersection between fractures. The higher N, the higher the accuracy of the model. The main assumption was using a quasi steady state hypothesis, that states that the characteristic diffusion time over one single fracture is negligible compared with the characteristic time of the macroscopic problem, e.g. change of boundary conditions. In that context, the lowest order approximation N = 1 has the form of solving a transient problem in a resistor/capacitor network, a so-called pipe network. Its topology is the same as the network of geometrical intersections between fractures. In this paper, we generalize this approach in order to account for fluxes from matrix to fractures. The quasi steady state hypothesis at the fracture level is still kept. Then, we show that in the case of well separated time scales between matrix and fractures, the preceding model needs only to be slightly modified in order to incorporate these fluxes. The additional knowledge of the so-called matrix to fracture transfer function allows to modify the mass matrix that becomes a time convolution operator. This is reminiscent of existing space averaged transient dual porosity models.

Investigation of micro-gravity effects on heat pipe thermal performance and working fluid behavior, phase B

NASA Technical Reports Server (NTRS)

Gier, K. D.; Smith, M. O.

1990-01-01

The purpose of this experiment is to develop an in-depth understanding of the behavior of heat pipes in space. Both fixed conductance heat pipes (FCHPs) with axial grooves and variable conductance heat pipes (VCHPs) with porous wicks will be investigated. This understanding will be applied to the development of improved performance heat pipes subjected to various accelerations in space, including those encountered on a lunar base or Mars mission. More efficient, reliable, and lighter weight spacecraft thermal control systems should result from these investigations.

Heat pipe investigations

NASA Technical Reports Server (NTRS)

Marshburn, J. P.

1972-01-01

The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

Heat Pipe Planets

NASA Technical Reports Server (NTRS)

Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

2014-01-01

When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

Experimental operation of a sodium heat pipe

NASA Astrophysics Data System (ADS)

Holtz, R. E.; McLennan, G. A.; Koehl, E. R.

1985-05-01

This report documents the operation of a 28 in. long sodium heat pipe in the Heat Pipe Test Facility (HPTF) installed at Argonne National Laboratory. Experimental data were collected to simulate conditions prototypic of both a fluidized bed coal combustor application and a space environment application. Both sets of experiment data show good agreement with the heat pipe analytical model. The heat transfer performance of the heat pipe proved reliable over a substantial period of operation and over much thermal cycling. Additional testing of longer heat pipes under controlled laboratory conditions will be necessary to determine performance limitations and to complete the design code validation.

Heat pipes in space and on earth

NASA Technical Reports Server (NTRS)

Ollendorf, S.

1978-01-01

The performance of heat pipes used in the thermal control system of spacecraft such as OAO-III and ATS-6 is discussed, and applications of heat pipes to permafrost stabilization on the Alaska Pipeline and to heat recovery systems are described. Particular attention is given to the ATS-6, launched in 1974, which employs 55 heat pipes to carry solar and internal power loads to radiator surfaces. In addition, experiments involving radiative cooling based on cryogenic heat pipes have been planned for the Long Duration Exposure Facility spacecraft and for Spacelab. The role of heat pipes in Space Shuttle heat rejection services is also mentioned.

A Capsule-Type Electromagnetic Acoustic Transducer for Fast Screening of External Corrosion in Nonmagnetic Pipes.

PubMed

Li, Yong; Cai, Rui; Yan, Bei; Zainal Abidin, Ilham Mukriz; Jing, Haoqing; Wang, Yi

2018-05-28

For fuel transmission and structural strengthening, small-diameter pipes of nonmagnetic materials are extensively adopted in engineering fields including aerospace, energy, transportation, etc. However, the hostile and corrosive environment leaves them vulnerable to external corrosion which poses a severe threat to structural integrity of pipes. Therefore, it is imperative to nondestructively detect and evaluate the external corrosion in nonmagnetic pipes. In light of this, a capsule-type Electromagnetic Acoustic Transducer (EMAT) for in-situ nondestructive evaluation of nonmagnetic pipes and fast screening of external corrosion is proposed in this paper. A 3D hybrid model for efficient prediction of responses from the proposed transducer to external corrosion is established. Closed-form expressions of field quantities of electromagnetics and EMAT signals are formulated. Simulations based on the hybrid model indicate feasibility of the proposed transducer in detection and evaluation of external corrosion in nonmagnetic pipes. In parallel, experiments with the fabricated transducer have been carried out. Experimental results are supportive of the conclusion drawn from simulations. The investigation via simulations and experiments implies that the proposed capsule-type EMAT is capable of fast screening of external corrosion, which is beneficial to the in-situ nondestructive evaluation of small-diameter nonmagnetic pipes.

The Iceland Deep Drilling Project (IDDP): Deep Fluid Sampling in Fractured Quartz, Reykjanes Geothermal System, Iceland

NASA Astrophysics Data System (ADS)

Seward, R. J.; Reed, M. H.; Grist, H. R.; Fridriksson, T.; Danielsen, P.; Thorhallsson, S.; Elders, W. A.; Fridleifsson, G. O.

2011-12-01

In July of 2011 a fluid inclusion tool (FIT) was deployed in well RN-17b of the Reykjanes geothermal system, Iceland, with the goal of sampling fluids in situ at the deepest feed point in the well. The tool consists of a perforated stainless steel pipe containing eight stainless steel mesh canisters, each loaded with 10mm-scale blocks of thermally fractured quartz. Except for one control canister, in each canister the fractured quartz blocks were surrounded by a different grain size of SiO¬2 glass that ranged in size from 10μm-scale glass wool to cm-scale glass shards. The FIT was left in the well on a wireline at a depth of 2768m and retrieved after three weeks. The fluid at 2768m depth is known from November 2010 well logs to have a temperature of about 330°C and pressure of 170 bars, a pressure ~40 bar too high for boiling at that temperature. After retrieval, quartz in all of the canisters contained liquid-dominated fluid inclusions, but their quantity and size differed by canister. Groups of inclusions occur in healed fractures and both healed and open fracture surfaces are visible within single quartz blocks. Measurements on a heating and cooling stage yield approximant inclusion homogenization temperatures of 332°C and freezing points of -2.0°C. These measurements and a pressure of 170 bars yield trapping temperatures of 335°C and a NaCl weight percent of 3.4, both of which match known values, thus verifying that the device trapped fluids as intended. In upcoming studies, these fluids will be analyzed using bulk methods and LA-ICP-MS on individual inclusions. The glass added to the quartz blocks in the canisters allowed the Reykjanes fluids to precipitate enough quartz to heal fractures and trap fluids despite the fluid undersaturation in quartz. Almost all of the glass that was added to the canisters, 27 to 66 grams in each (except glass wool), was consumed in the experiment. Remaining glass was in the non-mesh bottom caps of the canisters where fluid flux may have been minimal, indicating that most of the dissolved SiO2 was carried away with flowing fluid. This may explain why not all fractures were healed, as they were in our previous closed-system laboratory experiments. Upon recovery from the well, the FIT and the canister contents were covered in fine black particles, the greatest quantity by far occurring in canisters that had contained glass wool as the SiO2 source. Preliminary SEM-EDS analyses show that the particles contain silica, iron, magnesium, and small amounts of zinc sulfide. The precipitation of sulfides from the fluid sampled in the quartz fractures provides a valuable constraint on interpretation of the fluid inclusion compositions.

Visualization of various working fluids flow regimes in gravity heat pipe

NASA Astrophysics Data System (ADS)

Nemec, Patrik

Heat pipe is device working with phase changes of working fluid inside hermetically closed pipe at specific pressure. The phase changes of working fluid from fluid to vapour and vice versa help heat pipe to transport high heat flux. Amount of heat flux transferred by heat pipe, of course depends on kind of working fluid. The article deal about visualization of various working fluids flow regimes in glass gravity heat pipe by high speed camera and processes casing inside during heat pipe operation. Experiment working fluid flow visualization is performed with two glass heat pipes with different inner diameter (13 mm and 22 mm) filled with water, ethanol and fluorinert FC 72. The working fluid flow visualization explains the phenomena as a working fluid boiling, nucleation of bubbles, and vapour condensation on the wall, vapour and condensate flow interaction, flow down condensate film thickness on the wall occurred during the heat pipe operation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roos, E.; Maier, V.; Nagel, G.

The break preclusion concept is based on {open_quotes}KTA rules{close_quotes}, {open_quotes}RSK guidelines{close_quotes} and {open_quotes}Rahmenspeziflkation Basissicherheit{close_quotes}. These fundamental rules containing for example requirements on material, design, calculation, manufacturing and testing procedures are explained and the technical realisation is shown by means of examples. The proof of the quality of these piping systems can be executed by means of fracture mechanics calculations by showing that in every case the leakage monitoring system already detect cracks which are clearly smaller than the critical crack. Thus the leak before break behavior and the break preclusion concept is implicitly affirmed. In order to further diminish conservativitiesmore » in the fracture mechanics procedures, specific research projects are executed which are explained in this contribution.« less

Safety review package for University of Central Florida flat-plate heat pipe experiment

NASA Technical Reports Server (NTRS)

Chow, Louis C.

1998-01-01

A flat-plate heat pipe (FPHP) experiment has been set up for micro-gravity tests on a NASA supplied aircraft. This report presents an analysis on various components of the experimental setup to certify that it will satisfy the flight safety and operation requirements.

These Pipes Are "Happening"

ERIC Educational Resources Information Center

Skophammer, Karen

2010-01-01

The author is blessed with having the water pipes for the school system in her office. In this article, the author describes how the breaking of the pipes had led to a very worthwhile art experience for her students. They practiced contour and shaded drawing techniques, reviewed patterns and color theory, and used their reasoning skills--all while…

Experimental and Model Studies on Loading Path-Dependent and Nonlinear Gas Flow Behavior in Shale Fractures

NASA Astrophysics Data System (ADS)

Li, Honglian; Lu, Yiyu; Zhou, Lei; Tang, Jiren; Han, Shuaibin; Ao, Xiang

2018-01-01

Interest in shale gas as an energy source is growing worldwide. Because the rock's natural fracture system can contribute to gas production, it is important to understand the flow behavior of natural fractures in shale. Previous studies on the flow characteristics in shale fractures were limited and did not consider the effect of nonlinearity. To understand the basic mechanics of the gas flow behavior in shale fractures, laboratory investigations with consideration of the fluid pressure gradient, the confining stress, the loading history and the fracture geometry were conducted in this paper. Izbash's equation was used to analyze the nonlinearity of the flow. The results show that the behavior of the friction factors is similar to that shown in flow tests in smooth and rough pipes. The increase of the confining stress and the irreversible damage to the shale decreased the hydraulic aperture and increased the relative roughness. Thus, turbulent flow could appear at a low Reynolds number, resulting in a significant pressure loss. The limits of the cubic law and the existing correction factor for transmissivity are discussed. It is found that the previous friction models overestimate the friction factor in the laminar regime and underestimate the friction factor in the turbulent regime. For this reason, a new friction model based on a linear combination of the Reynolds number and the relative roughness was developed.

Monetary and social impact measures of visitor experience and the effects of a piping plover recovery program on visitor experience

Treesearch

Laura Gilbert

1995-01-01

This study examined visitor perceptions and attitudes towards their experience at a national wildlife refuge which limits access to its barrier beach during the nesting season of the threatened piping plover. It determined attitudes towards the closure, as well as what factors influenced these attitudes. It also examined how willingness to pay for refuge protection...

Structure, Dynamic Cracking Resistance, and Crack Growth Micromechanism in Pipe Billets after Thermomechanical Treatment

NASA Astrophysics Data System (ADS)

Simonov, M. Yu.; Simonov, Yu. N.; Shaimanov, G. S.

2018-01-01

The structure, dynamic cracking resistance, and micromechanisms of crack growth in initially highly tempered pipe billets made of structural carbon steel are studied after thermomechanical treatment, including cold plastic deformation by radial forging followed by annealing, under various conditions. The strength is found to be maximum after cold radial forging followed by annealing at 300°C. Cold radial forging and annealing at 600°C are shown to cause the formation of an ultrafine-grained structure with an average grain/subgrain size of 900 nm. The structural features formed in both the axial and the transverse direction after cold radial forging have been revealed. The mechanism of crack growth after heat treatment and thermomechanical treatment has been studied. The fracture surface elements formed during dynamic-crackingresistance tests have been qualitatively analyzed.

Geochemical exploration for mineralized breccia pipes in northern Arizona, U.S.A.

USGS Publications Warehouse

Wenrich, K.J.

1986-01-01

Thousands of solution-collapse breccia pipe crop out in the canyons and on the plateaus of northern Arizona. Over 80 of these are known to contain U or Cu mineralized rock. The high-grade U ore associated with potentially economic concentrations of Ag, Pb, Zn, Cu, Co and Ni in some of these pipes has continued to stimulate mining and exploration activity in northern Arizona, despite periods of depressed U prices. Large expanses of northern Arizona are comprised of undissected high plateaus; recognition of pipes in these areas is particularly important because mining access to the plateaus is far better than to the canyons. The small size of the pipes, generally less than 600 ft (200 m) in diameter, and limited rock outcrop on the plateaus, compounds the recognition problem. Although the breccia pipes, which bottom in the Mississippian Redwall Limestone, are occasionally exposed on the plateaus as circular features, so are unmineralized near-surface collapse features that bottom in the Permian Kaibab and Toroweap Formations. The distinction between these two classes of circular features is critical during exploration for this unique type of U deposit. Various geochemical and geophysical exploration methods have been tested over these classes of collapse features. Because of the small size of the deposits, and the low-level geochemical signatures in the overlying rock that are rarely dispersed for distances in excess of several hundred feet, most reconnaissance geochemical surveys, such as hydrogeochemistry or stream sediment, will not delineete mineralized pipes. Several types of detailed geochemical surveys made over collapse features, located through examination of aerial photographs and later field mapping, have been successful at delineating collapse features from the surrounding host rock: (1) Rock geochemistry commonly shows low level Ag, As, Ba, Co, Cu, Ni, Pb, Se and Zn anomalies over mineralized breccia pipes; (2) Soil surveys appear to have the greatest potential for distinguishing mineralized breccia pipes from the surrounding terrane. Although the soil anomalies are only twice the background concentrations for most anomalous elements, traverses made over collapse features show consistent enrichment inside of the feature as compared to outside; (3) B. Cereus surveys over a known mineralized pipe show significantly more anomalous samples collected from within the ring fracture than from outside of the breccia pipe; (4) Helium soil-gas surveys were made over 7 collapse features with discouraging results from 5 of the 7 features. Geophysical surveys indicate that scaler audio-magnetotelluric (AMT) and E-field telluric profile data show diagnostic conductivity differences over mineralized pipes as compared to the surrounding terrane. These surveys, coupled with the geochemical surveys conducted as detailed studies over features mapped by field and aerial photograph examination, can be a significant asset in the selection of potential breccia pipes for drilling. ?? 1986.

Theory and design of variable conductance heat pipes

NASA Technical Reports Server (NTRS)

Marcus, B. D.

1972-01-01

A comprehensive review and analysis of all aspects of heat pipe technology pertinent to the design of self-controlled, variable conductance devices for spacecraft thermal control is presented. Subjects considered include hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, materials compatibility and variable conductance control techniques. The report includes a selected bibliography of pertinent literature, analytical formulations of various models and theories describing variable conductance heat pipe behavior, and the results of numerous experiments on the steady state and transient performance of gas controlled variable conductance heat pipes. Also included is a discussion of VCHP design techniques.

Analysis, Verification, and Application of Equations and Procedures for Design of Exhaust-pipe Shrouds

NASA Technical Reports Server (NTRS)

Ellerbrock, Herman H.; Wcislo, Chester R.; Dexter, Howard E.

1947-01-01

Investigations were made to develop a simplified method for designing exhaust-pipe shrouds to provide desired or maximum cooling of exhaust installations. Analysis of heat exchange and pressure drop of an adequate exhaust-pipe shroud system requires equations for predicting design temperatures and pressure drop on cooling air side of system. Present experiments derive such equations for usual straight annular exhaust-pipe shroud systems for both parallel flow and counter flow. Equations and methods presented are believed to be applicable under certain conditions to the design of shrouds for tail pipes of jet engines.

Feasibility of Locating Leakages in Sewage Pressure Pipes Using the Distributed Temperature Sensing Technology.

PubMed

Apperl, Benjamin; Pressl, Alexander; Schulz, Karsten

2017-01-01

The cost effective maintenance of underwater pressure pipes for sewage disposal in Austria requires the detection and localization of leakages. Extrusion of wastewater in lakes can heavily influence the water and bathing quality of surrounding waters. The Distributed Temperature Sensing (DTS) technology is a widely used technique for oil and gas pipeline leakage detection. While in pipeline leakage detection, fiber optic cables are installed permanently at the outside or within the protective sheathing of the pipe; this paper aims at testing the feasibility of detecting leakages with temporary introduced fiber optic cable inside the pipe. The detection and localization were tested in a laboratory experiment. The intrusion of water from leakages into the pipe, producing a local temperature drop, served as indicator for leakages. Measurements were taken under varying measurement conditions, including the number of leakages as well as the positioning of the fiber optic cable. Experiments showed that leakages could be detected accurately with the proposed methodology, when measuring resolution, temperature gradient and measurement time were properly selected. Despite the successful application of DTS for leakage detection in this lab environment, challenges in real system applications may arise from temperature gradients within the pipe system over longer distances and the placement of the cable into the real pipe system.

Application of Non-pressure Reinforced Concrete Pipes in Modern Construction and Reconstruction of Highways

NASA Astrophysics Data System (ADS)

Rakitin, B. A.; Pogorelov, S. N.; Kolmogorova, A. O.

2017-11-01

Modern highway construction technologies provide for the quality water discharge systems to increase facilities’ service life. Pipeline operating conditions require the use of durable and reliable materials and structures. The experience in using reinforced concrete pipes for these purposes shows their utilization efficiency. The present paper considers the experience in the use of non-pressure reinforced concrete pipes manufactured by the German company SCHLOSSER-PFEIFFER under the Ural region geological and climatic conditions. The authors analyzed the actual operation of underground pipelines and effective loads upon them. A detailed study of the mechanical properties of reinforced concrete pipes is necessary to improve their production technology and to enhance their serviceability. The use of software-based methods helped to develop a mathematical model and to estimate the strength and crack resistance of reinforced concrete pipes at different laying depths. The authors carried out their complex research of the strain-stress behaviour of reinforced concrete pipes and identified the most hazardous sections in the structure. The calculations performed were confirmed by the results of laboratory tests completed in the construction materials, goods, and structures test center. Based on the completed research, the authors formulated their recommendations to improve the design and technology of non-pressure reinforced concrete pipes.

The Effect of Loading Rate on Hydraulic Fracturing in Synthetic Granite - a Discrete Element Study

NASA Astrophysics Data System (ADS)

Tomac, I.; Gutierrez, M.

2015-12-01

Hydraulic fracture initiation and propagation from a borehole in hard synthetic rock is modeled using the two dimensional Discrete Element Method (DEM). DEM uses previously established procedure for modeling the strength and deformation parameters of quasi-brittle rocks with the Bonded Particle Model (Itasca, 2004). A series of simulations of laboratory tests on granite in DEM serve as a reference for synthetic rock behavior. Fracturing is enabled by breaking parallel bonds between DEM particles as a result of the local stress state. Subsequent bond breakage induces fracture propagation during a time-stepping procedure. Hydraulic fracturing occurs when pressurized fluid induces hoop stresses around the wellbore which cause rock fracturing and serves for geo-reservoir permeability enhancement in oil, gas and geothermal industries. In DEM, a network of fluid pipes and reservoirs is used for mathematical calculation of fluid flow through narrow channels between DEM particles, where the hydro-mechanical coupling is fully enabled. The fluid flow calculation is superimposed with DEM stress-strain calculation at each time step. As a result, the fluid pressures during borehole pressurization in hydraulic fracturing, as well as, during the fracture propagation from the borehole, can be simulated. The objective of this study is to investigate numerically a hypothesis that fluid pressurization rate, or the fluid flow rate, influences upon character, shape and velocity of fracture propagation in rock. The second objective is to better understand and define constraints which are important for successful fracture propagation in quasi-brittle rock from the perspective of flow rate, fluid density, viscosity and compressibility relative to the rock physical properties. Results from this study indicate that not only too high fluid flow rates cause fracture arrest and multiple fracture branching from the borehole, but also that the relative compressibility of fracturing fluid and rock plays a significant role in fracture propagation velocity. Fluid viscosity effects are similar to the loading rate effects, because in both cases the rapid buildup of the pressure in the wellbore in absence of the inflow of the fluid into initiated fracture causes induction of multiple simultaneous fracture branches at the wellbore wall.

Development of cryogenic thermal control heat pipes. [of stainless steels

NASA Technical Reports Server (NTRS)

1978-01-01

The development of thermal control heat pipes that are applicable to the low temperature to cryogenic range was investigated. A previous effort demonstrated that stainless steel axially grooved tubing which met performance requirements could be fabricated. Three heat pipe designs utilizing stainless steel axially grooved tubing were fabricated and tested. One is a liquid trap diode heat pipe which conforms to the configuration and performance requirements of the Heat Pipe Experiment Package (HEPP). The HEPP is scheduled for flight aboard the Long Duration Flight Exposure Facility (LDEF). Another is a thermal switch heat pipe which is designed to permit energy transfer at the cooler of the two identical legs. The third thermal component is a hybrid variable conductance heat pipe (VCHP). The design incorporates both a conventional VCHP system and a liquid trap diode. The design, fabrication and thermal testing of these heat pipes is described. The demonstrated heat pipe behavior including start-up, forward mode transport, recovery after evaporator dry-out, diode performance and variable conductance control are discussed.

Variable conductance heat pipe technology

NASA Technical Reports Server (NTRS)

Marcus, B. D.; Edwards, D. K.; Anderson, W. T.

1973-01-01

Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft.

Experiment 2033. Injection Test of Upper EE-3 Fracture Zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grigsby, Charles O.

1983-09-12

This experiment is designed to investigate the apparent lithologic boundary between the low-opening-pressure fracture system (upper EE-3 fracture and Phase I system) and the high-opening-pressure fracture system (lower fracture in EE-3 and in EE-2). The experiment will test for resistence to breakthrough into the lower EE-2 fracture system at relatively low pressure and will define the veting behavior of the low pressure system.

Static elastica formulations of a pine conveying fluid

NASA Astrophysics Data System (ADS)

Thompson, J. M. T.; Lunn, T. S.

1981-07-01

An elastic pipe in an equilibrium configuration of arbitrary large deflection discharging fluid from its end experiences static centrifugal and frictional drag forces along its complete length. These are, however, entirely equivalent to an end follower force of magnitude ρ AV2. This equivalence is examined in detail by using the intrinsic field equations which are suitable for closed form solutions in terms of elliptic integrals. Once the pipe moves it also experiences gyroscopic Coriolis forces along its length, but these are not considered in this static examination. It is shown in detail how a discharging pipe with end forces and moments is statically equivalent to a beam or strut with the same end forces and moments plus the reversed momentum vector ρ AV2. It is seen that a cantilevered pipe with a free end can have no statical equilibrium states at all, at either large or small deflections, while pipes with constrained ends have large static deflections identical to those of the equivalent struts.

Synthetic Aperture Focusing Technique 3D-CAD-SAFT

NASA Astrophysics Data System (ADS)

Schmitz, V.; Kröning, M.; Chakhlov, S.; Fischer, W.

2000-05-01

Till the 80's ultrasonic holography has been used as an analyzing technique, a procedure which has been replaced by the Synthetic Aperture Focusing Technique "SAFT." This technique has been applied on metallic components in different power plants, mostly on pipe systems on pressure vessels or on specimen made of composite or concrete material. SAFT exists in different versions, either in 2D or 3D, for plane or arbitrarily shaped surfaces, for pulse echo or pitch- and catch arrangements. The defect sizes ranged from 100 μm in turbine shafts till fractures of meters in research pressure vessels. The paper covers the lastest results of the SAFT-reconstruction technique under Windows NT which has been guided by the experience obtained in the field. It contributes to the currently discussed question of the possible benefit using TOFD—techniques versus pulse echo techniques; the target has been a fatigue crack in a pipe segment which was investigated by different insonification angles, wave modes and probe arrangements. The results are evaluated with respect to signal-to-noise ratio improvement; problems of TOFD are demonstrated using an animation procedure which allows to walk through the weld in three orthogonal directions. A special example will be shown from a bore hole inspection of water power station valves where the reconstruction procedure follows the radial axial insonification planes. The multi-line SAFT images can be cut according to the situation of the crack position and orientation.

Fracture Behavior of Ultra-Low-Carbon Steel Plate and Heat-Affected-Zone.

DTIC Science & Technology

1990-12-01

ferrite . This effect on the transformation kinetics of steel is shown in Fig. 2. This alloying addition, however, has experienced...V-notch ITT of -76’F (-600C). The design philo.ophy used for this alloy required that the steel be low carbon with a nearly 100% acicular ferrite ...line pipe fitting steel by International Nickel Company and was called IN 787. It is a low carbon-manganese steel strengthened with a fine precipitate

Experimental study of the influence of low frequency flow modulation on the whistling behavior of a corrugated pipe.

PubMed

Kristiansen, Ulf R; Mattei, Pierre-Olivier; Pinhede, Cedric; Amielh, Muriel

2011-10-01

It is well known that airflow in a corrugated pipe can excite whistling at the frequencies of the pipe's longitudinal acoustic modes. This short contribution reports on the results of experiments where a low frequency, oscillating flow with velocity magnitudes of the same order as the airflow has been added. Depending on the oscillation strength, it has been found that this flow may silence the pipe or move the whistling to higher harmonics. It is also shown that the low frequency oscillation itself may excite higher frequency whistling sounds in the pipe. © 2011 Acoustical Society of America

Passive cryogenic cooling of electrooptics with a heat pipe/radiator.

PubMed

Nelson, B E; Goldstein, G A

1974-09-01

The current status of the heat pipe is discussed with particular emphasis on applications to cryogenic thermal control. The competitive nature of the passive heat pipe/radiator system is demonstrated through a comparative study with other candidate systems for a 1-yr mission. The mission involves cooling a spaceborne experiment to 100 K while it dissipates 10 W.

Experience with flexible pipe in sour service environment: A case study (the Arabian Gulf)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Maslamani, M.J.

The suitability of a flexible pipe was evaluated on a trial basis for a lift gas line in a sour oil field in the State of Qatar, in the Arabian Gulf. Flexible pipes have been successfully used in the oil and gas industries for transportation of methanol, benzene and gas condensates in wet sweet environment at temperatures of up to 80 C. However, there is little or no information available as to its corrosion resistance in sour service wells containing 6% CO{sub 2} with 3% mole H{sub 2}S and at moderate temperatures. The present experience with a flexible pipe inmore » the gas field of Qatar has shown that under sour service conditions, the layered, composite material can suffer severe degradation leading to failure. A detailed inspection and failure analysis of the flexible pipe forms the basis of this paper. The failure demonstrates the significant effects of stress level, environmental aggressiveness, and localized hard zones in promoting Sulfide Stress Cracking (SSC). Permeability of this sour gas through the composite layer of the flexible pipe resulted in varying degree of sulfide attack and hydrogen embrittlement depending on the susceptibility of the multi layered material.« less

Characterization of a high performance ultra-thin heat pipe cooling module for mobile hand held electronic devices

NASA Astrophysics Data System (ADS)

Ahamed, Mohammad Shahed; Saito, Yuji; Mashiko, Koichi; Mochizuki, Masataka

2017-11-01

In recent years, heat pipes have been widely used in various hand held mobile electronic devices such as smart phones, tablet PCs, digital cameras. With the development of technology these devices have different user friendly features and applications; which require very high clock speeds of the processor. In general, a high clock speed generates a lot of heat, which needs to be spreaded or removed to eliminate the hot spot on the processor surface. However, it is a challenging task to achieve proper cooling of such electronic devices mentioned above because of their confined spaces and concentrated heat sources. Regarding this challenge, we introduced an ultra-thin heat pipe; this heat pipe consists of a special fiber wick structure named as "Center Fiber Wick" which can provide sufficient vapor space on the both sides of the wick structure. We also developed a cooling module that uses this kind of ultra-thin heat pipe to eliminate the hot spot issue. This cooling module consists of an ultra-thin heat pipe and a metal plate. By changing the width, the flattened thickness and the effective length of the ultra-thin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module. In addition, other experiments were also conducted to determine the effects of changes in the number of heat pipes in a single module. Characterization and comparison of the module have also been conducted both experimentally and theoretically.

The specific light output of cesium iodide crystals

NASA Technical Reports Server (NTRS)

Gregory, J. C.

1976-01-01

Large area ion chambers for a high energy cosmic ray experiment, scintillating plastic fibers as light pipes for a cosmic ray hodoscope, and an evaluation of clad scintillating light pipes were considered.

Water Leak Detection by Using Ground Penetrating Radar, Synthetic Simulation and Four-Dimensional Visualization

NASA Astrophysics Data System (ADS)

Al-Shukri, H.; Eyuboglu, S.; Mahdi, H.

2005-12-01

Many geophysical techniques have been suggested as candidates for detecting water leakage in water distribution system, including ground penetrating radar (GPR), acoustic devices, and gas sampling devices. A series of laboratory experiments were conducted to determine the validity and effectiveness of GPR in detecting water leakage in metal and plastic PVC pipes. The goal was to derive a practical and robust procedure for detecting such leakage. Initially, prototype laboratory experiments were designed to simulate leaks in both PVC and metal pipe. The experiments were very well controlled and results obtained indicate that GPR is effective in detecting subsurface water leaks. This was followed by an outdoor life size experiments. 50 feet by 30 feet by 5 feet test bed was constructed using local soil and commercial water distribution pipes. A 400 MHz antenna was used to collect three-dimensional GPR data as a function of time for a number of experiments using different type of pipes. Advanced imaging and visualization technology was used to further analyze the data. The UALR Virtual Reality Center CAVE facilities were utilized to accomplish this test. Results obtained indicate that GPR is effective in detecting subsurface water leaks in both pipes. Synthetic models of the GPR signals based on Finite Difference Time Domain Method (FDTD) were built to help select an appropriate equipment configuration (frequency band, type of antenna, and real-time imaging software) prior to data acquisition. The simulation software was used to determine the near-field radiation characteristics of the GPR antenna. Different experimental models were adapted for which observational GPR data was previously collected. Matlab regression analysis was used to generate the incident waves for each model to ensure highly accurate and controlled experiments.

Langley Research Center Standard for the Evaluation of Socket Welds

NASA Technical Reports Server (NTRS)

Berry, R. F., Jr.

1985-01-01

A specification utilized for the nondestructive evaluation of socket type pipe joints at Langley Research Center (LaRC) is discussed. The scope of hardware shall include, but is not limited to, all common pipe fittings: tees, elbows, couplings, caps, and so forth, socket type flanges, unions, and valves. In addition, the exterior weld of slip on flanges shall be inspected using this specification. At the discretion of the design engineer, standard practice engineer, Fracture Mechanics Engineering Section, Pressure Systems Committee, or other authority, four nondestructive evaluation techniques may be utilized exclusively, or in combination, to inspect socket type welds. These techniques are visual, radiographic, magnetic particle, and dye penetrant. Under special circumstances, other techniques (such as eddy current or ultrasonics) may be required and their application shall be guided by the appropriate sections of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PVC).

Seismic texture and amplitude analysis of large scale fluid escape pipes using time lapses seismic surveys: examples from the Loyal Field (Scotland, UK)

NASA Astrophysics Data System (ADS)

Maestrelli, Daniele; Jihad, Ali; Iacopini, David; Bond, Clare

2016-04-01

Fluid escape pipes are key features of primary interest for the analysis of vertical fluid flow and secondary hydrocarbon migration in sedimentary basin. Identified worldwide (Løset et al., 2009), they acquired more and more importance as they represent critical pathways for supply of methane and potential structure for leakage into the storage reservoir (Cartwright & Santamarina, 2015). Therefore, understanding their genesis, internal characteristics and seismic expression, is of great significance for the exploration industry. Here we propose a detailed characterization of the internal seismic texture of some seal bypass system (e.g fluid escape pipes) from a 4D seismic survey (released by the BP) recently acquired in the Loyal Field. The seal by pass structure are characterized by big-scale fluid escape pipes affecting the Upper Paleogene/Neogene stratigraphic succession in the Loyal Field, Scotland (UK). The Loyal field, is located on the edge of the Faroe-Shetland Channel slope, about 130 km west of Shetland (Quadrants 204/205 of the UKCS) and has been recently re-appraised and re developed by a consortium led by BP. The 3D detailed mapping analysis of the full and partial stack survey (processed using amplitude preservation workflows) shows a complex system of fluid pipe structure rooted in the pre Lista formation and developed across the paleogene and Neogene Units. Geometrical analysis show that pipes got diameter varying between 100-300 m and a length of 500 m to 2 km. Most pipes seem to terminate abruptly at discrete subsurface horizons or in diffuse termination suggesting multiple overpressured events and lateral fluid migration (through Darcy flows) across the overburden units. The internal texture analysis of the large pipes, (across both the root and main conduit zones), using near, medium and far offset stack dataset (processed through an amplitude preserved PSTM workflow) shows a tendency of up-bending of reflection (rather than pulls up artefacts) affected by large scale fracture (semblance image) and seem consistent with a suspended mud/sand mixture non-fluidized fluid flow. Near-Middle-Far offsets amplitude analysis confirms that most of the amplitude anomalies within the pipes conduit and terminus are only partly related to gas. An interpretation of the possible texture observed is proposed with a discussion of the noise and artefact induced by resolution and migration problems. Possible hypothetical formation mechanisms for those Pipes are discussed.

Energy transfer mechanism and probability analysis of submarine pipe laterally impacted by dropped objects

NASA Astrophysics Data System (ADS)

Liang, Jing; Yu, Jian-xing; Yu, Yang; Lam, W.; Zhao, Yi-yu; Duan, Jing-hui

2016-06-01

Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.

Final Development, Testing, and Flight Preparation of the Rigidizable Get-Away-Special Experiment (RIGEX)

DTIC Science & Technology

2007-06-01

threads connected to a steel braided hose with ¼” pipe ends. The steel braided hose is then connected to a ¼” 107 three-way union, which is...which can be switched back and forth, are connected to the nitrogen and vacuum source. The nitrogen source is connected through a steel braided hose ...from hot piping during hot runs. This is where most of the cryogenic piping and valves are mounted. The piping near the pump and the flex hose at

Simulation studies on Tube End Expansion of AA2014 Alloy Tubes

NASA Astrophysics Data System (ADS)

Venugopal, L.; Prasad, N. E. C.; Geeta Krishna, P.; Praveen, L.

2018-03-01

End forming is defined as forming the end of tubular forms either by inverting the tube or by expanding it. It finds application in many fields such as in automotive and aerospace sectors as power transmission elements, fuel lines, exhaust pipes etc. The main aim of the present work is to expand the AA2014 alloy tubes with different die sets without any fracture. Deform 2D software was used for performing simulations on expanding the tubes with different die set (punch) values having differed forming angles (α = 15°, 30° and 45°) and expansion ratios (rp/r0 = 1.39, 1.53 and 1.67). Experiments were also conducted and the results correlate with the simulation results. The results shows that for the punch having less cone angle (α) values the linear displacement is more rather than higher cone angles. But in the case of higher cone angles the radial displacement is more than the linear displacement.

Effect of isolated fractures on accelerated flow in unsaturated porous rock

USGS Publications Warehouse

Su, Grace W.; Nimmo, John R.; Dragila, Maria I.

2003-01-01

Fractures that begin and end in the unsaturated zone, or isolated fractures, have been ignored in previous studies because they were generally assumed to behave as capillary barriers and remain nonconductive. We conducted a series of experiments using Berea sandstone samples to examine the physical mechanisms controlling flow in a rock containing a single isolated fracture. The input fluxes and fracture orientation were varied in these experiments. Visualization experiments using dyed water in a thin vertical slab of rock were conducted to identify flow mechanisms occurring due to the presence of the isolated fracture. Two mechanisms occurred: (1) localized flow through the rock matrix in the vicinity of the isolated fracture and (2) pooling of water at the bottom of the fracture, indicating the occurrence of film flow along the isolated fracture wall. These mechanisms were observed at fracture angles of 20 and 60 degrees from the horizontal, but not at 90 degrees. Pooling along the bottom of the fracture was observed over a wider range of input fluxes for low‐angled isolated fractures compared to high‐angled ones. Measurements of matrix water pressures in the samples with the 20 and 60 degree fractures also demonstrated that preferential flow occurred through the matrix in the fracture vicinity, where higher pressures occurred in the regions where faster flow was observed in the visualization experiments. The pooling length at the terminus of a 20 degree isolated fracture was measured as a function of input flux. Calculations of the film flow rate along the fracture were made using these measurements and indicated that up to 22% of the flow occurred as film flow. These experiments, apparently the first to consider isolated fractures, demonstrate that such features can accelerate flow through the unsaturated zone and should be considered when developing conceptual models.

Centrifuge Testing of a Partially-Confined FC-72 Spray

DTIC Science & Technology

2006-11-01

induced body forces. Heat transfer associated with closed - loop spray cooling will be affected by acceleration body forces, the extent of which is not...impingement cooling, spray cooling, heat pipes , loop heat pipes , carbon foam impregnated with phase-change materials, and combinations of the above...reduced gravity and elevated gravity experiments to help prove viability of pulsating heat pipes (PHPs) for space applications. The PHPs, filled

Minimization of the negative influence on the biosphere in heavy oil extraction and ecologically clean technology for the injection of the steam with supercritical parameters in oil strata on the basis of new ecologically clean tubing pipes with heat-resistant coatings

NASA Astrophysics Data System (ADS)

Komkov, M. A.; Moiseev, V. A.; Tarasov, V. A.; Timofeev, M. P.

2015-12-01

Some ecological problems related to heavy-oil extraction and ways for minimizing the negative impacts of this process on the biosphere are discussed. The ecological hazard of, for example, frequently used multistage hydraulic fracturing of formation is noted and the advantages and perspectives of superheated steam injection are considered. Steam generators of a new type and ecologically clean and costeffective insulating for tubing pipes (TPs) are necessary to develop the superheated steam injection method. The article is devoted to solving one of the most important and urgent tasks, i.e., the development and usage of lightweight, nonflammable, environmentally safe, and cost-effective insulating materials. It is shown that, for tubing shielding operating at temperatures up to 420°C, the most effective thermal insulation is a highly porous material based on basalt fiber. The process of filtration deposition of short basalt fibers with a bunch of alumina thermal insulation tubing pipe coatings in the form of cylinders and cylindrical shells from liquid pulp is substantiated. Based on the thermophysical characteristics of basalt fibers and on the technological features of manufacturing highly porous coating insulation, the thickness of a tubing pipe is determined. During the prolonged pumping of the air at an operating temperature of 400°C in the model sample of tubing pipes with insulation and a protective layer, we find that the surface temperature of the thermal barrier coating does not exceed 60°C. Introducing the described technology will considerably reduce the negative impact of heavy-oil extraction on the biosphere.

Hydraulic Fracturing Mineback Experiment in Complex Media

NASA Astrophysics Data System (ADS)

Green, S. J.; McLennan, J. D.

2012-12-01

Hydraulic fracturing (or "fracking") for the recovery of gas and liquids from tight shale formations has gained much attention. This operation which involves horizontal well drilling and massive hydraulic fracturing has been developed over the last decade to produce fluids from extremely low permeability mudstone and siltstone rocks with high organic content. Nearly thirteen thousand wells and about one hundred and fifty thousand stages within the wells were fractured in the US in 2011. This operation has proven to be successful, causing hundreds of billions of dollars to be invested and has produced an abundance of natural gas and is making billions of barrels of hydrocarbon liquids available for the US. But, even with this commercial success, relatively little is clearly known about the complexity--or lack of complexity--of the hydraulic fracture, the extent that the newly created surface area contacts the high Reservoir Quality rock, nor the connectivity and conductivity of the hydraulic fractures created. To better understand this phenomena in order to improve efficiency, a large-scale mine-back experiment is progressing. The mine-back experiment is a full-scale hydraulic fracture carried out in a well-characterized environment, with comprehensive instrumentation deployed to measure fracture growth. A tight shale mudstone rock geologic setting is selected, near the edge of a formation where one to two thousand feet difference in elevation occurs. From the top of the formation, drilling, well logging, and hydraulic fracture pumping will occur. From the bottom of the formation a horizontal tunnel will be mined using conventional mining techniques into the rock formation towards the drilled well. Certain instrumentation will be located within this tunnel for observations during the hydraulic fracturing. After the hydraulic fracturing, the tunnel will be extended toward the well, with careful mapping of the created hydraulic fracture. Fracturing fluid will be traceable, as will injected proppant, in order to demarcate in-situ fracture paths and fluid and proppant progression. This underground experiment is referred to as a "mine-back experiment". Several mine-back experiments have been conducted in the past, and have demonstrated complex, diffuse fracture systems in coals and bundled fracture systems in some sandstones. No mine-back experiment has been conducted in the tight shales; but, economics and environmental considerations dictate that more definitive measurements will be extremely helpful to establish fracture growth patterns and to validate monitoring methods such as micro-seismic measurements. This presentation discusses the mine-back experiment and presents details of geologic setting, hydraulic fracturing, and the excavation required before and after the hydraulic fracture. The mine-back experiment will provide ground-truth assessment of hydraulic fracturing, geologic forecasting, micro-seismicity, and other information.

Advances in directional borehole radar data analysis and visualization

USGS Publications Warehouse

Smith, D.V.G.; Brown, P.J.

2002-01-01

The U.S. Geological Survey is developing a directional borehole radar (DBOR) tool for mapping fractures, lithologic changes, and underground utility and void detection. An important part of the development of the DBOR tool is data analysis and visualization, with the aim of making the software graphical user interface (GUI) intuitive and easy to use. The DBOR software system consists of a suite of signal and image processing routines written in Research Systems' Interactive Data Language (IDL). The software also serves as a front-end to many widely accepted Colorado School of Mines Center for Wave Phenomena (CWP) Seismic UNIX (SU) algorithms (Cohen and Stockwell, 2001). Although the SU collection runs natively in a UNIX environment, our system seamlessly emulates a UNIX session within a widely used PC operating system (MicroSoft Windows) using GNU tools (Noer, 1998). Examples are presented of laboratory data acquired with the prototype tool from two different experimental settings. The first experiment imaged plastic pipes in a macro-scale sand tank. The second experiment monitored the progress of an invasion front resulting from oil injection. Finally, challenges to further development and planned future work are discussed.

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE PAGES

Rutqvist, J.

2014-09-19

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutqvist, J.

The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore » in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

Laboratory hydraulic fracturing experiments in intact and pre-fractured rock

USGS Publications Warehouse

Zoback, M.D.; Rummel, F.; Jung, R.; Raleigh, C.B.

1977-01-01

Laboratory hydraulic fracturing experiments were conducted to investigate two factors which could influence the use of the hydrofrac technique for in-situ stress determinations; the possible dependence of the breakdown pressure upon the rate of borehole pressurization, and the influence of pre-existing cracks on the orientation of generated fractures. The experiments have shown that while the rate of borehole pressurization has a marked effect on breakdown pressures, the pressure at which hydraulic fractures initiate (and thus tensile strength) is independent of the rate of borehole pressurization when the effect of fluid penetration is negligible. Thus, the experiments indicate that use of breakdown pressures rather than fracture initiation pressures may lead to an erroneous estimate of tectonic stresses. A conceptual model is proposed to explain anomalously high breakdown pressures observed when fracturing with high viscosity fluids. In this model, initial fracture propagation is presumed to be stable due to large differences between the borehole pressure and that within the fracture. In samples which contained pre-existing fractures which were 'leaky' to water, we found it possible to generate hydraulic fractures oriented parallel to the direction of maximum compression if high viscosity drilling mud was used as the fracturing fluid. ?? 1977.

A prototype heat pipe heat exchanger for the capillary pumped loop flight experiment

NASA Technical Reports Server (NTRS)

Ku, Jentung; Yun, Seokgeun; Kroliczek, Edward J.

1992-01-01

A Capillary Pumped Two-Phase Heat Transport Loop (CAPL) Flight Experiment, currently planned for 1993, will provide microgravity verification of the prototype capillary pumped loop (CPL) thermal control system for EOS. CAPL employs a heat pipe heat exchanger (HPHX) to couple the condenser section of the CPL to the radiator assembly. A prototype HPHX consisting of a heat exchanger (HX), a header heat pipe (HHP), a spreader heat pipe (SHP), and a flow regulator has been designed and tested. The HX transmits heat from the CPL condenser to the HHP, while the HHP and SHP transport heat to the radiator assembly. The flow regulator controls flow distribution among multiple parallel HPHX's. Test results indicated that the prototype HPHX could transport up to 800 watts with an overall heat transfer coefficient of more than 6000 watts/sq m-deg C. Flow regulation among parallel HPHX's was also demonstrated.

Programmable immersive peripheral environmental system (PIPES): a prototype control system for environmental feedback devices

NASA Astrophysics Data System (ADS)

Frend, Chauncey; Boyles, Michael

2015-03-01

This paper describes an environmental feedback device (EFD) control system aimed at simplifying the VR development cycle. Programmable Immersive Peripheral Environmental System (PIPES) affords VR developers a custom approach to programming and controlling EFD behaviors while relaxing the required knowledge and expertise of electronic systems. PIPES has been implemented for the Unity engine and features EFD control using the Arduino integrated development environment. PIPES was installed and tested on two VR systems, a large format CAVE system and an Oculus Rift HMD system. A photocell based end-to-end latency experiment was conducted to measure latency within the system. This work extends previously unpublished prototypes of a similar design. Development and experiments described in this paper are part of the VR community goal to understand and apply environment effects to VEs that ultimately add to users' perceived presence.

Multiple fracturing experiments: propellant and borehole considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuderman, J F

1982-01-01

The technology for multiple fracturing of a wellbore, using progressively burning propellants, is being developed to enhance natural gas recovery. Multiple fracturing appears especially attractive for stimulating naturally fractured reservoirs such as Devonian shales where it is expected to effectively intersect existing fractures and connect them to a wellbore. Previous experiments and modeling efforts defined pressure risetimes required for multiple fracturing as a function of borehole diameter, but identified only a weak dependence on peak pressure attained. Typically, from four to eight equally spaced major fractures occur as a function of pressure risetime and in situ stress orientation. The presentmore » experiments address propellant and rock response considerations required to achieve the desired pressure risetimes for reliable multiple fracturing.« less

Heat pipes in solar collectors

NASA Astrophysics Data System (ADS)

Bairamov, R.; Toiliev, K.

The diode property of heat pipes is evaluated for use in solar collectors. Model experiments show that the effect of heat pipes in solar collectors is most pronounced during the nighttime, when solar radiation is zero, due to a significant reduction in the heat loss from the transparent cover surface of the collector compared to that for conventional collectors. For a solar collector with a glass cover area of one square meter during the summer season when the maximum water temperature is 60 C and the discharge is 85 l/sq m/day, the water temperature in the accumulator tank of the solar collector with a heat pipe is 10-11 C higher than in the solar collector lacking a heat pipe. In addition, the design of a solar house with passive systems in which heat pipes serve as the heat eliminating mechanism is discussed

Drag reduction of turbulent pipe flows by circular-wall oscillation

NASA Astrophysics Data System (ADS)

Choi, Kwing-So; Graham, Mark

1998-01-01

An experimental study on turbulent pipe flows was conducted with a view to reduce their friction drag by oscillating a section of the pipe in a circumferential direction. The results indicated that the friction factor of the pipe is reduced by as much as 25% as a result of active manipulation of near-wall turbulence structure by circular-wall oscillation. An increase in the bulk velocity was clearly shown when the pipe was oscillated at a constant head, supporting the measured drag reduction in the present experiment. The percentage reduction in pipe friction was found to be better scaled with the nondimensional velocity of the oscillating wall than with its nondimensional period, confirming a suggestion that the drag reduction seem to be resulted from the realignment of longitudinal vortices into a circumferential direction by the wall oscillation.

Identification of corrosion and damage mechanisms by using scanning electron microscopy and energy-dispersive X-ray microanalysis: contribution to failure analysis case histories

NASA Astrophysics Data System (ADS)

Pantazopoulos, G.; Vazdirvanidis, A.

2014-03-01

Emphasis is placed on the evaluation of corrosion failures of copper and machineable brass alloys during service. Typical corrosion failures of the presented case histories mainly focussed on stress corrosion cracking and dezincification that acted as the major degradation mechanisms in components used in piping and water supply systems. SEM assessment, coupled with EDS spectroscopy, revealed the main cracking modes together with the root-source(s) that are responsible for the damage initiation and evolution. In addition, fracture surface observations contributed to the identification of the incurred fracture mechanisms and potential environmental issues that stimulated crack initiation and propagation. Very frequently, the detection of chlorides among the corrosion products served as a suggestive evidence of the influence of working environment on passive layer destabilisation and metal dissolution.

Multiwell fracturing experiments. [Nitrogen foam fracture treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.

The objective of the Multiwell fracturing experiments is to test and develop the technology for the efficient stimulation of tight, lenticular gas sands. This requires basic understanding of: (1) fracture behavior and geometry in this complex lithologic environment, and (2) subsequent production into the created fracture. The intricate interplay of the hydraulic fracture with the lens geometry, the internal reservoir characteristics (fractures, reservoir breaks, etc.), the in situ stresses, and the mechanical defects (fracture, bedding, etc.) need to be defined in order to develop a successful stimulation program. The stimulation phase of the Multiwell Experiment is concerned with: (1) determiningmore » important rock/reservoir properties that influence or control fracture geometry and behavior, (2) designing fracture treatments to achieve a desired size and objectives, and (3) conducting post-treatment analyses to evaluate the effectiveness of the treatment. Background statement, project description, results and evaluation of future plans are presented. 5 refs., 2 figs., 2 tabs.« less

The Effect of Contact Area on the Fluid Flow-Fracture Specific Stiffness Relationship

NASA Astrophysics Data System (ADS)

Petrovitch, C.; Pyrak-Nolte, L. J.; Nolte, D. D.

2009-12-01

The integrity of subsurface CO2 sequestration sites can be compromised by the presence of mechanical discontinuities such as fractures, joints and faults. The ability to detect, seismically, and determine whether a discontinuity poses a risk, requires an understanding of the interrelationships among the mechanical, hydraulic and seismic properties of fractures rock. We performed a computational study to investigate the effect of fracture geometry on the relationship between fluid flow and fracture specific stiffness. The form of this relationship and the ability to scale it among different sample sizes provides a key link between the hydraulic and seismic response of fractures. In this study, model fracture topologies were simulated using the stratified continuum percolation method. This method constructs a hierarchical aperture distribution with a tunable spatial correlation length. Fractures with correlated and uncorrelated aperture distributions were used. The contact area across the fracture plane ranged from approximately 5% to 40%. The fracture specific stiffness was calculated by deforming each fracture numerically under a normal load and extracting the stiffness from the displacement-stress curves. Single-phase flow was calculated for each increment of stress by modeling the fracture topology as a network of elliptical pipes and solving the corresponding linear system of equations. We analyzed the relationship between fracture displacement and contact area and found that the correlation length associated with the contact area distribution enables a scaling relationship between displacement and contact area. The collapse of the fluid flow - stress relationship required use of standard percolation functional forms that use average aperture (cubic law), the void area fraction, and the correlation length of the contact area clusters. A final scaling relationship between fluid flow and fracture specific was found for the class of correlated fractures while a separate relationship was found for the uncorrelated fractures. By expanding the scaling parameters to include additional length scales, it may be possible to unify all of the flow-stiffness relationships, independent of geometry. Acknowledgments: The authors wish to acknowledge support of this work by the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy (DEFG02-97ER14785 08), the GeoMathematical Imaging Group at Purdue University and from the Computer Research Institute At Purdue University.

Water quality of flow through cured-in-place pipe (CIPP).

DOT National Transportation Integrated Search

2017-02-01

Though this study did not include replication, the preponderance of the data from field and simulated-field experiments indicates that Curedin- : Place Pipe (CIPP), with some care in enforcing the Caltrans specification and delaying the reintroductio...

Detection of underground water distribution piping system and leakages using ground penetrating radar (GPR)

NASA Astrophysics Data System (ADS)

Amran, Tengku Sarah Tengku; Ismail, Mohamad Pauzi; Ahmad, Mohamad Ridzuan; Amin, Mohamad Syafiq Mohd; Sani, Suhairy; Masenwat, Noor Azreen; Ismail, Mohd Azmi; Hamid, Shu-Hazri Abdul

2017-01-01

A water pipe is any pipe or tubes designed to transport and deliver water or treated drinking with appropriate quality, quantity and pressure to consumers. The varieties include large diameter main pipes, which supply entire towns, smaller branch lines that supply a street or group of buildings or small diameter pipes located within individual buildings. This distribution system (underground) is used to describe collectively the facilities used to supply water from its source to the point of usage. Therefore, a leaking in the underground water distribution piping system increases the likelihood of safe water leaving the source or treatment facility becoming contaminated before reaching the consumer. Most importantly, leaking can result in wastage of water which is precious natural resources. Furthermore, they create substantial damage to the transportation system and structure within urban and suburban environments. This paper presents a study on the possibility of using ground penetrating radar (GPR) with frequency of 1GHz to detect pipes and leakages in underground water distribution piping system. Series of laboratory experiment was designed to investigate the capability and efficiency of GPR in detecting underground pipes (metal and PVC) and water leakages. The data was divided into two parts: 1. detecting/locating underground water pipe, 2. detecting leakage of underground water pipe. Despite its simplicity, the attained data is proved to generate a satisfactory result indicating GPR is capable and efficient, in which it is able to detect the underground pipe and presence of leak of the underground pipe.

Microbiology, chemistry and biofilm development in a pilot drinking water distribution system with copper and plastic pipes.

PubMed

Lehtola, Markku J; Miettinen, Ilkka T; Keinänen, Minna M; Kekki, Tomi K; Laine, Olli; Hirvonen, Arja; Vartiainen, Terttu; Martikainen, Pertti J

2004-10-01

We studied the changes in water quality and formation of biofilms occurring in a pilot-scale water distribution system with two generally used pipe materials: copper and plastic (polyethylene, PE). The formation of biofilms with time was analysed as the number of total bacteria, heterotrophic plate counts and the concentration of ATP in biofilms. At the end of the experiment (after 308 days), microbial community structure, viable biomass and gram-negative bacterial biomass were analysed via lipid biomarkers (phospholipid fatty acids and lipopolysaccharide 3-hydroxy fatty acids), and the numbers of virus-like particles and total bacteria were enumerated by SYBR Green I staining. The formation of biofilm was slower in copper pipes than in the PE pipes, but after 200 days there was no difference in microbial numbers between the pipe materials. Copper ion led to lower microbial numbers in water during the first 200 days, but thereafter there were no differences between the two pipe materials. The number of virus-like particles was lower in biofilms and in outlet water from the copper pipes than PE pipes. Pipe material influenced also the microbial and gram-negative bacterial community structure in biofilms and water.

Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology

PubMed Central

Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting. PMID:29551957

Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology.

PubMed

Chen, Fengchen; Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting.

Water quality of flow through cured-in-place pipe (CIPP) : final report.

DOT National Transportation Integrated Search

2017-02-01

Though this study did not include replication, the preponderance of the data from field and simulated-field experiments indicates that Curedin-Place : Pipe (CIPP), with some care in enforcing the Caltrans specification and delaying the reintroduction...

Experimental investigation of heat transfer characteristics of guar-based polymer solutions and gels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azouz, I.; Vinod, P.S.; Shah, S.N.

1996-12-31

An experimental investigation of the heat transfer characteristics of hydraulic fracturing fluids was conducted at the Fracturing Fluid Characterization Facility (FFCF) of the University of Oklahoma. The facility is equipped with a high pressure fracture simulator, coiled tubing fluid pre-conditioning system, and a full-scale, counter-current, double pipe heat exchanger. The fluids investigated include non-crosslinked and borate-crosslinked guar gum and hydroxypropyl guar (HPG). Results were also obtained for water and were used as a basis for comparison. The effects of flow rate, operating temperature, pH, and various levels of shear pre-conditioning, on the heat transfer behavior of the test fluids weremore » investigated. Results show a significant difference between the heat transfer coefficient of the pure solvent (water) and those of the polymer solutions tested. While all polymer solutions tested exhibited lower heat transfer coefficients than that of the pure solvent, crosslinking appears to enhance the heat transfer characteristics of the polymer fluids. It was also observed that shear preconditioning does not seem to have a significant effect on the heat transfer coefficient of the crosslinked gels. These findings are of great interest to the industry, especially to the petroleum industry where these fluids are commonly used during hydraulic fracturing of hydrocarbon reservoirs.« less

Primary vesicles, vesicle-rich segregation structures and recognition of primary and secondary porosities in lava flows from the Paraná igneous province, southern Brazil

NASA Astrophysics Data System (ADS)

Barreto, Carla Joana S.; de Lima, Evandro F.; Goldberg, Karin

2017-04-01

This study focuses on a volcanic succession of pāhoehoe to rubbly lavas of the Paraná-Etendeka Province exposed in a single road profile in southernmost Brazil. This work provides an integrated approach for examining primary vesicles and vesicle-rich segregation structures at the mesoscopic scale. In addition, this study provides a quantitative analysis of pore types in thin section. We documented distinct distribution patterns of vesicle and vesicle-rich segregation structures according to lava thickness. In compound pāhoehoe lavas, the cooling allows only vesicles (<1 cm size) and pipe vesicles to be frozen into place. In inflated pāhoehoe lavas, vesicles of different sizes are common, including pipe vesicles, and also segregation structures such as proto-cylinders, cylinders, cylinder sheets, vesicle sheets, and pods. In rubbly lavas, only vesicles of varying sizes occur. Gas release from melt caused the formation of primary porosity, while hydrothermal alteration and tectonic fracturing are the main processes that generated secondary porosity. Although several forms of porosity were created in the basaltic lava flows, the precipitation of secondary minerals within the pores has tended to reduce the original porosities. Late-stage fractures could create efficient channel networks for possible hydrocarbon/groundwater migration and entrapment owing to their ability to connect single pores. Quantitative permeability data should be gathered in future studies to confirm the potential of these lavas for store hydrocarbons or groundwater.

Ultrasonic guided waves in eccentric annular pipes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pattanayak, Roson Kumar; Balasubramaniam, Krishnan; Rajagopal, Prabhu

2014-02-18

This paper studies the feasibility of using ultrasonic guided waves to rapidly inspect tubes and pipes for possible eccentricity. While guided waves are well established in the long range inspection of structures such as pipes and plates, studies for more complex cross sections are limited and analytical solutions are often difficult to obtain. Recent developments have made the Semi Analytical Finite Element (SAFE) method widely accessible for researchers to study guided wave properties in complex structures. Here the SAFE method is used to study the effect of eccentricity on the modal structures and velocities of lower order guided wave modesmore » in thin pipes of diameters typically of interest to the industry. Results are validated using experiments. The paper demonstrates that even a small eccentricity in the pipe can strongly affect guided wave mode structures and velocities and hence shows potential for pipe eccentricity inspection.« less

Wind tunnel data of the analysis of heat pipe and wind catcher technology for the built environment

PubMed Central

Calautit, John Kaiser; Chaudhry, Hassam Nasarullah; Hughes, Ben Richard

2015-01-01

The data presented in this article were the basis for the study reported in the research articles entitled ‘Climate responsive behaviour heat pipe technology for enhanced passive airside cooling’ by Chaudhry and Hughes [10] which presents the passive airside cooling capability of heat pipes in response to gradually varying external temperatures and related to the research article “CFD and wind tunnel study of the performance of a uni-directional wind catcher with heat transfer devices” by Calautit and Hughes [1] which compares the ventilation performance of a standard roof mounted wind catcher and wind catcher incorporating the heat pipe technology. Here, we detail the wind tunnel test set-up and inflow conditions and the methodologies for the transient heat pipe experiment and analysis of the integration of heat pipes within the control domain of a wind catcher design. PMID:26958604

Wind tunnel data of the analysis of heat pipe and wind catcher technology for the built environment.

PubMed

Calautit, John Kaiser; Chaudhry, Hassam Nasarullah; Hughes, Ben Richard

2015-12-01

The data presented in this article were the basis for the study reported in the research articles entitled 'Climate responsive behaviour heat pipe technology for enhanced passive airside cooling' by Chaudhry and Hughes [10] which presents the passive airside cooling capability of heat pipes in response to gradually varying external temperatures and related to the research article "CFD and wind tunnel study of the performance of a uni-directional wind catcher with heat transfer devices" by Calautit and Hughes [1] which compares the ventilation performance of a standard roof mounted wind catcher and wind catcher incorporating the heat pipe technology. Here, we detail the wind tunnel test set-up and inflow conditions and the methodologies for the transient heat pipe experiment and analysis of the integration of heat pipes within the control domain of a wind catcher design.

Chill Down Process of Hydrogen Transport Pipelines

NASA Technical Reports Server (NTRS)

Mei, Renwei; Klausner, James

2006-01-01

A pseudo-steady model has been developed to predict the chilldown history of pipe wall temperature in the horizontal transport pipeline for cryogenic fluids. A new film boiling heat transfer model is developed by incorporating the stratified flow structure for cryogenic chilldown. A modified nucleate boiling heat transfer correlation for cryogenic chilldown process inside a horizontal pipe is proposed. The efficacy of the correlations is assessed by comparing the model predictions with measured values of wall temperature in several azimuthal positions in a well controlled experiment by Chung et al. (2004). The computed pipe wall temperature histories match well with the measured results. The present model captures important features of thermal interaction between the pipe wall and the cryogenic fluid, provides a simple and robust platform for predicting pipe wall chilldown history in long horizontal pipe at relatively low computational cost, and builds a foundation to incorporate the two-phase hydrodynamic interaction in the chilldown process.

Analysis of collapse in flattening a micro-grooved heat pipe by lateral compression

NASA Astrophysics Data System (ADS)

Li, Yong; He, Ting; Zeng, Zhixin

2012-11-01

The collapse of thin-walled micro-grooved heat pipes is a common phenomenon in the tube flattening process, which seriously influences the heat transfer performance and appearance of heat pipe. At present, there is no other better method to solve this problem. A new method by heating the heat pipe is proposed to eliminate the collapse during the flattening process. The effectiveness of the proposed method is investigated through a theoretical model, a finite element(FE) analysis, and experimental method. Firstly, A theoretical model based on a deformation model of six plastic hinges and the Antoine equation of the working fluid is established to analyze the collapse of thin walls at different temperatures. Then, the FE simulation and experiments of flattening process at different temperatures are carried out and compared with theoretical model. Finally, the FE model is followed to study the loads of the plates at different temperatures and heights of flattened heat pipes. The results of the theoretical model conform to those of the FE simulation and experiments in the flattened zone. The collapse occurs at room temperature. As the temperature increases, the collapse decreases and finally disappears at approximately 130 °C for various heights of flattened heat pipes. The loads of the moving plate increase as the temperature increases. Thus, the reasonable temperature for eliminating the collapse and reducing the load is approximately 130 °C. The advantage of the proposed method is that the collapse is reduced or eliminated by means of the thermal deformation characteristic of heat pipe itself instead of by external support. As a result, the heat transfer efficiency of heat pipe is raised.

Rotating optical geometry sensor for inner pipe-surface reconstruction

NASA Astrophysics Data System (ADS)

Ritter, Moritz; Frey, Christan W.

2010-01-01

The inspection of sewer or fresh water pipes is usually carried out by a remotely controlled inspection vehicle equipped with a high resolution camera and a lightning system. This operator-oriented approach based on offline analysis of the recorded images is highly subjective and prone to errors. Beside the subjective classification of pipe defects through the operator standard closed circuit television (CCTV) technology is not suitable for detecting geometrical deformations resulting from e.g. structural mechanical weakness of the pipe, corrosion of e.g. cast-iron material or sedimentations. At Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB) in Karlsruhe, Germany, a new Rotating Optical Geometry Sensor (ROGS) for pipe inspection has been developed which is capable of measuring the inner pipe geometry very precisely over the whole pipe length. This paper describes the developed ROGS system and the online adaption strategy for choosing the optimal system parameters. These parameters are the rotation and traveling speed dependent from the pipe diameter. Furthermore, a practicable calibration methodology is presented which guarantees an identification of the several internal sensor parameters. ROGS has been integrated in two different systems: A rod based system for small fresh water pipes and a standard inspection vehicle based system for large sewer Pipes. These systems have been successfully applied to different pipe systems. With this measurement method the geometric information can be used efficiently for an objective repeatable quality evaluation. Results and experiences in the area of fresh water pipe inspection will be presented.

Analysis of flame acceleration in open or vented obstructed pipes

NASA Astrophysics Data System (ADS)

Bychkov, Vitaly; Sadek, Jad; Akkerman, V'yacheslav

2017-01-01

While flame propagation through obstacles is often associated with turbulence and/or shocks, Bychkov et al. [V. Bychkov et al., Phys. Rev. Lett. 101, 164501 (2008), 10.1103/PhysRevLett.101.164501] have revealed a shockless, conceptually laminar mechanism of extremely fast flame acceleration in semiopen obstructed pipes (one end of a pipe is closed; a flame is ignited at the closed end and propagates towards the open one). The acceleration is devoted to a powerful jet flow produced by delayed combustion in the spaces between the obstacles, with turbulence playing only a supplementary role in this process. In the present work, this formulation is extended to pipes with both ends open in order to describe the recent experiments and modeling by Yanez et al. [J. Yanez et al., arXiv:1208.6453] as well as the simulations by Middha and Hansen [P. Middha and O. R. Hansen, Process Safety Prog. 27, 192 (2008) 10.1002/prs.10242]. It is demonstrated that flames accelerate strongly in open or vented obstructed pipes and the acceleration mechanism is similar to that in semiopen ones (shockless and laminar), although acceleration is weaker in open pipes. Starting with an inviscid approximation, we subsequently incorporate hydraulic resistance (viscous forces) into the analysis for the sake of comparing its role to that of a jet flow driving acceleration. It is shown that hydraulic resistance is actually not required to drive flame acceleration. In contrast, this is a supplementary effect, which moderates acceleration. On the other hand, viscous forces are nevertheless an important effect because they are responsible for the initial delay occurring before the flame acceleration onset, which is observed in the experiments and simulations. Accounting for this effect provides good agreement between the experiments, modeling, and the present theory.

Test program for transmitter experiment package and heat pipe system for the communications technology satellite

NASA Technical Reports Server (NTRS)

Depauw, J. F.; Reader, K. E.; Staskus, J. V.

1976-01-01

The test program is described for the 200 watt transmitter experiment package and the variable conductance heat pipe system which are components of the high-power transponder aboard the Communications Technology Satellite. The program includes qualification tests to demonstrate design adequacy, acceptance tests to expose latent defects in flight hardware, and development tests to integrate the components into the transponder system and to demonstrate compatibility.

Buoyant miscible displacement flow of shear-thinning fluids: Experiments and Simulations

NASA Astrophysics Data System (ADS)

Ale Etrati Khosroshahi, Seyed Ali; Frigaard, Ian

2017-11-01

We study displacement flow of two miscible fluids with density and viscosity contrast in an inclined pipe. Our focus is mainly on displacements where transverse mixing is not significant and thus a two-layer, stratified flow develops. Our experiments are carried out in a long pipe, covering a wide range of flow-rates, inclination angles and viscosity ratios. Density and viscosity contrasts are achieved by adding Glycerol and Xanthan gum to water, respectively. At each angle, flow rate and viscosity ratio are varied and density contrast is fixed. We identify and map different flow regimes, instabilities and front dynamics based on Fr , Re / Frcosβ and viscosity ratio m. The problem is also studied numerically to get a better insight into the flow structure and shear-thinning effects. Numerical simulations are completed using OpenFOAM in both pipe and channel geometries and are compared against the experiments. Schlumberger, NSERC.

A Taguchi approach on optimal process control parameters for HDPE pipe extrusion process

NASA Astrophysics Data System (ADS)

Sharma, G. V. S. S.; Rao, R. Umamaheswara; Rao, P. Srinivasa

2017-06-01

High-density polyethylene (HDPE) pipes find versatile applicability for transportation of water, sewage and slurry from one place to another. Hence, these pipes undergo tremendous pressure by the fluid carried. The present work entails the optimization of the withstanding pressure of the HDPE pipes using Taguchi technique. The traditional heuristic methodology stresses on a trial and error approach and relies heavily upon the accumulated experience of the process engineers for determining the optimal process control parameters. This results in setting up of less-than-optimal values. Hence, there arouse a necessity to determine optimal process control parameters for the pipe extrusion process, which can ensure robust pipe quality and process reliability. In the proposed optimization strategy, the design of experiments (DoE) are conducted wherein different control parameter combinations are analyzed by considering multiple setting levels of each control parameter. The concept of signal-to-noise ratio ( S/ N ratio) is applied and ultimately optimum values of process control parameters are obtained as: pushing zone temperature of 166 °C, Dimmer speed at 08 rpm, and Die head temperature to be 192 °C. Confirmation experimental run is also conducted to verify the analysis and research result and values proved to be in synchronization with the main experimental findings and the withstanding pressure showed a significant improvement from 0.60 to 1.004 Mpa.

GHGfrack: An Open-Source Model for Estimating Greenhouse Gas Emissions from Combustion of Fuel during Drilling and Hydraulic Fracturing.

PubMed

Vafi, Kourosh; Brandt, Adam

2016-07-19

This paper introduces GHGfrack, an open-source engineering-based model that estimates energy consumption and associated GHG emissions from drilling and hydraulic fracturing operations. We describe verification and calibration of GHGfrack against field data for energy and fuel consumption. We run GHGfrack using data from 6927 wells in Eagle Ford and 4431 wells in Bakken oil fields. The average estimated energy consumption in Eagle Ford wells using lateral hole diameters of 8 (3)/4 and 6 (1)/8 in. are 2.25 and 2.73 TJ/well, respectively. The average estimated energy consumption in Bakken wells using hole diameters of 6 in. for horizontal section is 2.16 TJ/well. We estimate average greenhouse gas (GHG) emissions of 419 and 510 tonne of equivalent CO2 per well (tonne of CO2 eq/well) for the two aforementioned assumed geometries in Eagle Ford, respectively, and 417 tonne of CO2 eq/well for the case of Bakken. These estimates are limited only to GHG emissions from combustion of diesel fuel to supply energy only for rotation of drill string, drilling mud circulation, and fracturing pumps. Sensitivity analysis of the model shows that the top three key variables in driving energy intensity in drilling are the lateral hole diameter, drill pipe internal diameter, and mud flow rate. In hydraulic fracturing, the top three are lateral casing diameter, fracturing fluid volume, and length of the lateral.

CHLORINE DECAY AND BIOFILM STUDIES IN A PILOT SCALE DRINKING WATER DISTRIBUTION DEAD END PIPE SYSTEM

EPA Science Inventory

Chlorine decay experiments using a pilot-scale water distribution dead end pipe system were conducted to define relationships between chlorine decay and environmental factors. These included flow rate, biomass concentration and biofilm density, and initial chlorine concentrations...

Microgravity

NASA Image and Video Library

2000-11-03

On the Space Shuttle Orbiter Atlantis' middeck, Astronaut Donald R. McMonagle, mission commander, works with the Heat Pipe Performance (HPP-2) experiment during STS-66 mission. HPP-2 was flown to investigate the thermal performance and fluid dynamics of heat pipes operating with asymmetric and multiple heating zones under microgravity condition.

Further experiments for mean velocity profile of pipe flow at high Reynolds number

NASA Astrophysics Data System (ADS)

Furuichi, N.; Terao, Y.; Wada, Y.; Tsuji, Y.

2018-05-01

This paper reports further experimental results obtained in high Reynolds number actual flow facility in Japan. The experiments were performed in a pipe flow with water, and the friction Reynolds number was varied up to Reτ = 5.3 × 104. This high Reynolds number was achieved by using water as the working fluid and adopting a large-diameter pipe (387 mm) while controlling the flow rate and temperature with high accuracy and precision. The streamwise velocity was measured by laser Doppler velocimetry close to the wall, and the mean velocity profile, called log-law profile U+ = (1/κ) ln(y+) + B, is especially focused. After careful verification of the mean velocity profiles in terms of the flow rate accuracy and an evaluation of the consistency of the present results with those from previously measurements in a smaller pipe (100 mm), it was found that the value of κ asymptotically approaches a constant value of κ = 0.384.

Separation dynamics of dense dispersions in laminar pipe flows: An experimental and numerical study

NASA Astrophysics Data System (ADS)

Voulgaropoulos, Victor; Jamshidi, Rashid; Zainal Abidin, M. I. I.; Angeli, Panagiota

2017-11-01

The physical mechanisms governing the separation of dense liquid dispersed flows in pipes are not well understood. In this work, both experiments and numerical simulations are performed to investigate these mechanisms. Liquid-liquid dispersions are generated using a static mixer and their evolution is studied along a horizontal pipe (26mm ID) at laminar flow and input dispersed phase volume fractions up to 50%. To conduct optical measurements (PLIF and PIV) in the dense dispersions, the refractive index of both liquids is matched. Measurements are carried out at two axial locations downstream the mixer (15D and 135D, where D is the pipe diameter). Homogeneous dispersions, observed at 15D, segregate at 135D. The packing of the drops results in asymmetric velocity profiles and high slip velocities. The mixture approach is used in the numerical simulations, including gravity and shear-induced diffusion of drops. The predictions on separation and on velocity fields agree well with the experiments. Research funded by Chevron.

Slow fatigue testing of titanium grade 29 in air and seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atteraas, L.; Hersvik, G.; Solbakken, H.

1999-07-01

ASTM Grade 29 titanium has been fatigue tested in air and seawater at 110 C at a low frequency. The possible influence of seawater is completely masked by the fact that all the specimens of welded titanium, and most of the parent metal samples, had internal fracture initiations. Compared to the parent metal, the welded pipe specimens (5G orbital TIG) had a significantly lower fatigue life at the relatively high cyclic stress levels employed ({sigma}{sub max} = 0.85 {sigma}{sub y}). This is attributed to the presence of pores. Fractographic studies of failed weld metal specimens indicate that the fracture initiationmore » takes place in the material immediately surrounding a pore, with an abrupt crack formation, marking the beginning of the crack growth phase. The duration of the crack initiation phase shows large variations, whereas the growth phase duration varies little.« less

On the formation, growth, and shapes of solution pipes - insights from numerical modeling

NASA Astrophysics Data System (ADS)

Szymczak, Piotr; Tredak, Hanna; Upadhyay, Virat; Kondratiuk, Paweł; Ladd, Anthony J. C.

2015-04-01

Cylindrical, vertical structures called solution pipes are a characteristic feature of epikarst, encountered in different parts of the world, both in relatively cold areas such as England and Poland (where their formation is linked to glacial processes) [1] and in coastal areas in tropical or subtropical climate (Bermuda, Australia, South Africa, Caribbean, Mediterranean) [2,3]. They are invariably associated with weakly cemented, porous limestones and relatively high groundwater fluxes. Many of them develop under the colluvial sandy cover and contain the fill of clayey silt. Although it is widely accepted that they are solutional in origin, the exact mechanism by which the flow becomes focused is still under debate. The hypotheses include the concentration of acidified water around stems and roots of plants, or the presence of pre-existing fractures or steeply dipping bedding planes, which would determine the points of entry for the focused groundwater flows. However, there are field sites where neither of this mechanisms was apparently at play and yet the pipes are formed in large quantities [1]. In this communication we show that the systems of solution pipes can develop spontaneously in nearly uniform matrix due to the reactive-infiltration instability: a homogeneous porous matrix is unstable with respect to small variations in local permeability; regions of high permeability dissolve faster because of enhanced transport of reactants, which leads to increased rippling of the front. This leads to the formation of a system of solution pipes which then advance into the matrix. We study this process numerically, by a combination of 2d- and 3d-simulations, solving the coupled flow and transport equations at the Darcy scale. The relative simplicity of this system (pipes developing in a uniform porous matrix, without any pre-existing structure) makes it very attractive from the modeling standpoint. We quantify the factors which control the pipe diameters and the distances between the pipes as well as their growth rates. The most interesting result is the existence of two different regimes of the piped growth, depending on the flow rate. At high flow rates, well-separated, cyllindrical shafts are formed, of a nearly uniform diameter all along their lengths. They advance quickly into the matrix, with velocities several times larger than that of a unperturbed, planar dissolution front. Conversely, for small flow rates, the pipes are funnel-shaped with parabolic tips and their advancement velocity is of the same order as that of a planar front. The transition between the two forms is abrupt, with no intermediate forms observed. The simulation results are compared with field evidence from limestone quarries in Smerdyna, Poland, where several hundred of solution pipes have been exposed. Interestingly, both forms (shaft-like and tunnel-like) are found in the field, sometimes in close proximity to each other. [1] P. Walsh and I. Morawiecka-Zacharz, A dissolution pipe palaeokarst of mid-Pleistocene age preserved in Miocene limestones near Staszow, Poland, Palaeogeogr. Palaeoclimatol. Palaeoecol., 174 (2001), pp. 327-350. [2] K. G. Grimes, Solution pipes and pinnacles in syngenetic karst. In: Gines A., Knez M., Slabe T., Dreybrodt W. (Eds.), Karst Rock Features: Karren Sculpturing. Ljubljana, ZRC Publishing, (2009), pp. 513-523. [3] J. De Waele, S. E. Lauritzen and M. Parise On the formation of dissolution pipes in Quaternary coastal calcareous arenites in Mediterranean settings. Earth. Surf. Proc. Land" 36, (2011), pp. 143-157.

Experiments and Simulations of Fully Hydro-Mechanically Coupled Response of Rough Fractures Exposed to High-Pressure Fluid Injection

NASA Astrophysics Data System (ADS)

Vogler, D.; Settgast, R. R.; Annavarapu, C.; Madonna, C.; Bayer, P.; Amann, F.

2018-02-01

In this work, we present the application of a fully coupled hydro-mechanical method to investigate the effect of fracture heterogeneity on fluid flow through fractures at the laboratory scale. Experimental and numerical studies of fracture closure behavior in the presence of heterogeneous mechanical and hydraulic properties are presented. We compare the results of two sets of laboratory experiments on granodiorite specimens against numerical simulations in order to investigate the mechanical fracture closure and the hydro-mechanical effects, respectively. The model captures fracture closure behavior and predicts a nonlinear increase in fluid injection pressure with loading. Results from this study indicate that the heterogeneous aperture distributions measured for experiment specimens can be used as model input for a local cubic law model in a heterogeneous fracture to capture fracture closure behavior and corresponding fluid pressure response.

Experimental and analytical study of water pipe's rupture for damage identification purposes

NASA Astrophysics Data System (ADS)

Papakonstantinou, Konstantinos G.; Shinozuka, Masanobu; Beikae, Mohsen

2011-04-01

A malfunction, local damage or sudden pipe break of a pipeline system can trigger significant flow variations. As shown in the paper, pressure variations and pipe vibrations are two strongly correlated parameters. A sudden change in the flow velocity and pressure of a pipeline system can induce pipe vibrations. Thus, based on acceleration data, a rapid detection and localization of a possible damage may be carried out by inexpensive, nonintrusive monitoring techniques. To illustrate this approach, an experiment on a single pipe was conducted in the laboratory. Pressure gauges and accelerometers were installed and their correlation was checked during an artificially created transient flow. The experimental findings validated the correlation between the parameters. The interaction between pressure variations and pipe vibrations was also theoretically justified. The developed analytical model explains the connection among flow pressure, velocity, pressure wave propagation and pipe vibration. The proposed method provides a rapid, efficient and practical way to identify and locate sudden failures of a pipeline system and sets firm foundations for the development and implementation of an advanced, new generation Supervisory Control and Data Acquisition (SCADA) system for continuous health monitoring of pipe networks.

Comparison and validation of acoustic response models for wind noise reduction pipe arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marty, Julien; Denis, Stéphane; Gabrielson, Thomas

The detection capability of the infrasound component of the International Monitoring System (IMS) is tightly linked to the performance of its wind noise reduction systems. The wind noise reduction solution implemented at all IMS infrasound measurement systems consists of a spatial distribution of air inlets connected to the infrasound sensor through a network of pipes. This system, usually referred to as “pipe array,” has proven its efficiency in operational conditions. The objective of this paper is to present the results of the comparison and validation of three distinct acoustic response models for pipe arrays. The characteristics of the models andmore » the results obtained for a defined set of pipe array configurations are described. A field experiment using a newly developed infrasound generator, dedicated to the validation of these models, is then presented. The comparison between the modeled and empirical acoustic responses shows that two of the three models can be confidently used to estimate pipe array acoustic responses. Lastly, this study paves the way to the deconvolution of IMS infrasound data from pipe array responses and to the optimization of pipe array design to IMS applications.« less

Experimental research on crack detection in pipes based on Fiber Bragg grating

NASA Astrophysics Data System (ADS)

Cai, Lin; Wei, Qin; Yu, Zhaoxiang; Lu, Ming; Li, Xiaowei

2017-11-01

Crack is one of the primary faults in pipes, and its detection is a significant measure to ensure the safety of pipes. The feasibility of circumferential crack detection in pipes on the basis of fiber Bragg grating (FBG) detection technology is discussed through experimental research. Crack is formed on the surface of a metal pipe, the circumferential length of crack is one index of the damage degree. In the experiments, both electronic vibration sensor and FBG strain sensors are used to collect response signals of impulse excitation in different damage degrees. Furthermore, the characteristics of damage detection are analysed in both frequency domain and time domain. First, the natural frequencies are compared between practical and simulated results in different damage degrees of pipes; second, the multi-fractal detrended fluctuation analysis (MFDFA) is applied to acquire the singular values α as the characteristic parameter. The experimental results indicate that FBG strain sensors can perceive the impulse response of the pipe and change in different damage degrees effectively, like the vibration sensor. And both the natural frequency and the singular value are sensitive to increasing length of crack, they are able to distinguish different degrees of crack on the pipe.

Time Reversal Method for Pipe Inspection with Guided Wave

NASA Astrophysics Data System (ADS)

Deng, Fei; He, Cunfu; Wu, Bin

2008-02-01

The temporal-spatial focusing effect of the time reversal method on the guided wave inspection in pipes is investigated. A steel pipe model with outer diameter of 70 mm and wall thickness of 3.5 mm is numerically built to analyse the reflection coefficient of L(0,2) mode when the time reversal method is applied in the model. According to the calculated results, it is shown that a synthetic time reversal array method is effective to improve the signal-to-noise ratio of a guided wave inspection system. As an intercepting window is widened, more energy can be included in a re-emitted signal, which leads to a large reflection coefficient of L(0,2) mode. It is also shown that when a time reversed signal is reapplied in the pipe model, by analysing the motion of the time reversed wave propagating along the pipe model, a defect can be identified. Therefore, it is demonstrated that the time reversal method can be used to locate the circumferential position of a defect in a pipe. Finally, through an experiment corresponding with the pipe model, the experimental result shows that the above-mentioned method can be valid in the inspection of a pipe.

Comparison and validation of acoustic response models for wind noise reduction pipe arrays

DOE PAGES

Marty, Julien; Denis, Stéphane; Gabrielson, Thomas; ...

2017-02-13

The detection capability of the infrasound component of the International Monitoring System (IMS) is tightly linked to the performance of its wind noise reduction systems. The wind noise reduction solution implemented at all IMS infrasound measurement systems consists of a spatial distribution of air inlets connected to the infrasound sensor through a network of pipes. This system, usually referred to as “pipe array,” has proven its efficiency in operational conditions. The objective of this paper is to present the results of the comparison and validation of three distinct acoustic response models for pipe arrays. The characteristics of the models andmore » the results obtained for a defined set of pipe array configurations are described. A field experiment using a newly developed infrasound generator, dedicated to the validation of these models, is then presented. The comparison between the modeled and empirical acoustic responses shows that two of the three models can be confidently used to estimate pipe array acoustic responses. Lastly, this study paves the way to the deconvolution of IMS infrasound data from pipe array responses and to the optimization of pipe array design to IMS applications.« less

Acceleration of atmospheric Cherenkov telescope signal processing to real-time speed with the Auto-Pipe design system

NASA Astrophysics Data System (ADS)

Tyson, Eric J.; Buckley, James; Franklin, Mark A.; Chamberlain, Roger D.

2008-10-01

The imaging atmospheric Cherenkov technique for high-energy gamma-ray astronomy is emerging as an important new technique for studying the high energy universe. Current experiments have data rates of ≈20TB/year and duty cycles of about 10%. In the future, more sensitive experiments may produce up to 1000 TB/year. The data analysis task for these experiments requires keeping up with this data rate in close to real-time. Such data analysis is a classic example of a streaming application with very high performance requirements. This class of application often benefits greatly from the use of non-traditional approaches for computation including using special purpose hardware (FPGAs and ASICs), or sophisticated parallel processing techniques. However, designing, debugging, and deploying to these architectures is difficult and thus they are not widely used by the astrophysics community. This paper presents the Auto-Pipe design toolset that has been developed to address many of the difficulties in taking advantage of complex streaming computer architectures for such applications. Auto-Pipe incorporates a high-level coordination language, functional and performance simulation tools, and the ability to deploy applications to sophisticated architectures. Using the Auto-Pipe toolset, we have implemented the front-end portion of an imaging Cherenkov data analysis application, suitable for real-time or offline analysis. The application operates on data from the VERITAS experiment, and shows how Auto-Pipe can greatly ease performance optimization and application deployment of a wide variety of platforms. We demonstrate a performance improvement over a traditional software approach of 32x using an FPGA solution and 3.6x using a multiprocessor based solution.

Utilization of operating experience to prevent piping failures at steam plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, T.S.; Dietrich, E.B.

1999-11-01

The key to preventing flow-accelerated corrosion (FAC) induced piping failures in steam plants is the development and implementation of a methodical program for assessing plant susceptibility to FAC and managing the effects of FAC. One of the key elements of an effective FAC program is the accurate and comprehensive utilization of plant-specific and industry-wide operating experience. Operating experience should be used to develop the program to identify specific areas for inspection or replacement, and to maintain an effective program. This paper discusses the utilization of operating experience in FAC programs at nuclear power plants, fossil plants and other steam plants.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faidy, C.

Practical applications of the leak-before break concept are presently limited in French Pressurized Water Reactors (PWR) compared to Fast Breeder Reactors. Neithertheless, different fracture mechanic demonstrations have been done on different primary, auxiliary and secondary PWR piping systems based on similar requirements that the American NUREG 1061 specifications. The consequences of the success in different demonstrations are still in discussion to be included in the global safety assessment of the plants, such as the consequences on in-service inspections, leak detection systems, support optimization,.... A large research and development program, realized in different co-operative agreements, completes the general approach.

The Effect of fluid buoyancy and fracture orientation on CaCO3 Formation in a Fracture

NASA Astrophysics Data System (ADS)

Xu, Z.; Li, Q.; Sheets, J.; Kneafsey, T. J.; Jun, Y. S.; Cole, D. R.; Pyrak-Nolte, L. J.

2016-12-01

Sealing fractures through mineral precipitation is a potential way for improving caprock integrity in subsurface reservoirs. We investigated the effect of buoyancy and fracture orientation on the amount and spatial distribution of calcium carbonate (CaCO3) precipitates in a fracture. To monitor mineral precipitation during reactive flow, transparent acrylic casts of an induced fracture in Austin chalk were used. To trigger CaCO3 precipitates, 1M CaCl2 with either 0.6M NaHCO3 solution (for surface adhering precipitation), or 0.3M Na2CO3 solution (for pore filling precipitation) were injected simultaneously into a saturated fracture. Experiments were performed with the fracture plane oriented either parallel or perpendicular to gravity. Acoustic wave transmission (compressional wave, 1 MHz) and optical imaging were used to monitor the sample prior to, during and after fluid injection. Complementary X-ray computed tomography was performed throughout the experiments on vertical fractures and post injection for the horizontal fractures. For the vertical fractures, the denser CaCl2 almost completely displaced the carbonate solution in the fracture and caused strong localization of the precipitates. The width of the precipitated region grew slowly over time. The horizontal fracture caused the less dense carbonate to flow over the CaCl2 solution thus resulting in more mixing and a more even distribution of precipitates throughout the fracture. The acoustic signatures depended on the type of precipitation that occurred. For pore filling experiments, the compressional wave amplitude increased by 5-20% and the velocity increased for both the vertical and horizontal fractures. However, the acoustic responses differed between the vertical and horizontal fractures for surface adhering experiments. Based on the acoustic response, surface adhering precipitation increased fracture specific stiffness more in the horizontal fracture than in the vertical fracture. The horizontal fracture enabled more mixing of the two solutions within the fracture than the vertical fracture. This work was supported by the Center for Nanoscale Controls on Geologic CO (NCGC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-AC02-05CH11231

Mode I Fracture Toughness of Rock - Intrinsic Property or Pressure-Dependent?

NASA Astrophysics Data System (ADS)

Stoeckhert, F.; Brenne, S.; Molenda, M.; Alber, M.

2016-12-01

The mode I fracture toughness of rock is usually regarded as an intrinsic material parameter independent of pressure. However, most fracture toughness laboratory tests are conducted only at ambient pressure. To investigate fracture toughness of rock under elevated pressures, sleeve fracturing laboratory experiments were conducted with various rock types and a new numerical method was developed for the evaluation of these experiments. The sleeve fracturing experiments involve rock cores with central axial boreholes that are placed in a Hoek triaxial pressure cell to apply an isostatic confining pressure. A polymere tube is pressurized inside these hollow rock cylinders until they fail by tensile fracturing. Numerical simulations incorporating fracture mechanical models are used to obtain a relation between tensile fracture propagation and injection pressure. These simulations indicate that the magnitude of the injection pressure at specimen failure is only depending on the fracture toughness of the tested material, the specimen dimensions and the magnitude of external loading. The latter two are known parameters in the experiments. Thus, the fracture toughness can be calculated from the injection pressure recorded at specimen breakdown. All specimens had a borehole diameter to outer diameter ratio of about 1:10 with outer diameters of 40 and 62 mm. The length of the specimens was about two times the diameter. Maximum external loading was 7.5 MPa corresponding to maximum injection pressures at specimen breakdown of about 100 MPa. The sample set tested in this work includes Permian and Carboniferous sandstones, Jurassic limestones, Triassic marble, Permian volcanic rocks and Devonian slate from Central Europe. The fracture toughness values determined from the sleeve fracturing experiments without confinement using the new numerical method were found to be in good agreement with those from Chevron bend testing according to the ISRM suggested methods. At elevated confining pressures, the results indicate a significant positive correlation between fracture toughness and confining pressure for most tested rock types.

The small community solar thermal power experiment. Parabolic dish technology for industrial process heat application

NASA Technical Reports Server (NTRS)

Polzien, R. E.; Rodriguez, D.

1981-01-01

Aspects of incorporating a thermal energy transport system (ETS) into a field of parabolic dish collectors for industrial process heat (IPH) applications were investigated. Specific objectives are to: (1) verify the mathematical optimization of pipe diameters and insulation thicknesses calculated by a computer code; (2) verify the cost model for pipe network costs using conventional pipe network construction; (3) develop a design and the associated production costs for incorporating risers and downcomers on a low cost concentrator (LCC); (4) investigate the cost reduction of using unconventional pipe construction technology. The pipe network design and costs for a particular IPH application, specifically solar thermally enhanced oil recovery (STEOR) are analyzed. The application involves the hybrid operation of a solar powered steam generator in conjunction with a steam generator using fossil fuels to generate STEOR steam for wells. It is concluded that the STEOR application provides a baseline pipe network geometry used for optimization studies of pipe diameter and insulation thickness, and for development of comparative cost data, and operating parameters for the design of riser/downcomer modifications to the low cost concentrator.

Experiments and FEM simulations of fracture behaviors for ADC12 aluminum alloy under impact load

NASA Astrophysics Data System (ADS)

Hu, Yumei; Xiao, Yue; Jin, Xiaoqing; Zheng, Haoran; Zhou, Yinge; Shao, Jinhua

2016-11-01

Using the combination of experiment and simulation, the fracture behavior of the brittle metal named ADC12 aluminum alloy was studied. Five typical experiments were carried out on this material, with responding data collected on different stress states and dynamic strain rates. Fractographs revealed that the morphologies of fractured specimen under several rates showed different results, indicating that the fracture was predominantly a brittle one in nature. Simulations of the fracture processes of those specimens were conducted by Finite Element Method, whilst consistency was observed between simulations and experiments. In simulation, the Johnson- Cook model was chosen to describe the damage development and to predict the failure using parameters determined from those experimental data. Subsequently, an ADC12 engine mount bracket crashing simulation was conducted and the results indicated good agreement with the experiments. The accordance showed that our research can provide an accurate description for the deforming and fracture processes of the studied alloy.

Cooling Effect Analysis of Suppressing Coal Spontaneous Ignition with Heat Pipe

NASA Astrophysics Data System (ADS)

Zhang, Yaping; Zhang, Shuanwei; Wang, Jianguo; Hao, Gaihong

2018-05-01

Suppression of spontaneous ignition of coal stockpiles was an important issue for safe utilization of coal. The large thermal energy from coal spontaneous ignition can be viewed as the latent energy source to further utilize for saving energy purpose. Heat pipe was the more promising way to diffuse effectively concentrated energy of the coal stockpile, so that retarding coal spontaneous combustion was therefore highly desirable. The cooling mechanism of the coal with heat pipe was pursued. Based on the research result, the thermal energy can be transported from the coal seam to the surface continuously with the use of heat pipe. Once installed the heat pipes will work automatically as long as the coal oxidation reaction was happened. The experiment was indicated that it can significantly spread the high temperature of the coal pile.

The rotating heat pipe - Implementation as a uniform-temperature heat source

NASA Astrophysics Data System (ADS)

Limoges, R. F.

1981-11-01

A wickless rotating heat pipe, if properly controlled, is a uniform heat source. The data presented are based on work done with 12.7 cm diameter x 76 cm long rotating heat pipes operating between 120 and 140 C. The major areas reviewed are: materials of fabrication, working fluids, sealing, temperature control, heaters, and safety. The optimum rotating heat pipe defined by these studies is fabricated of type 304 stainless steel, uses water as the working fluid, is sealed with welded joints, and utilizes a pressure switch and a fast-response quartz lamp for temperature control. Surface-temperature control of + or - 0.15 C and temperature uniformity within 0.8 C are obtained. Results of experiments designed to study the effects of hydrogen in the enclosed volume of the heat pipe are presented.

Attenuation characteristics of the fundamental modes that propagate in buried iron water pipes.

PubMed

Long, R; Lowe, M; Cawley, P

2003-09-01

The attenuation of the fundamental non-torsional modes that propagate down buried iron water pipes has been studied. The mode shapes, mode attenuation due to leakage into the surrounding medium and the scattering of the modes as they interact with pipe joints and fittings have been investigated. In the low frequency region the mode predicted to dominate over significant propagation distances approximates a plane wave in the water within the pipe. The established acoustic technique used to locate leaks in buried iron water pipes assumes that leak noise propagates as a single non-dispersive mode at a velocity related to the low frequency asymptote of this water borne mode. Experiments have been conducted on buried water mains at test sites in the UK to verify the attenuation and velocity dispersion predictions.

Radionuclide migration: laboratory experiments with isolated fractures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rundberg, R.S.; Thompson, J.L.; Maestas, S.

Laboratory experiments examining flow and element migration in rocks containing isolated fractures have been initiated at the Los Alamos National Laboratory. Techniques are being developed to establish simple fracture flow systems which are appropriate to models using analytical solutions to the matrix diffusion-flow equations, such as those of I. Neretnieks [I. Neretnieks, Diffusion in the Rock Matrix: An Important Factor in Radionuclide Retardation? J. Geophys. Res. 85, 4379 (1980).] These experiments are intended to be intermediate steps toward larger scale field experiments where it may become more difficult to establish and control the parameters important to nuclide migration in fracturedmore » media. Laboratory experiments have been run on fractures ranging in size from 1 to 20 cm in length. The hydraulic flow in these fractures was studied to provide the effective apertures. The flows established in these fracture systems are similar to those in the granite fracture flow experiments of Witherspoon et al. [P.A. Witherspoon, J.S.Y. Wang, K. Iwai, and J.E. Gale, Validity of Cubic Law for Fluid Flow in a Deformable Rock Fracture, Lawrence Berkeley Laboratory report LBL-9557 (October 1979).] Traced solutions containing {sup 85}Sr and {sup 137}Cs were flowed through fractures in Climax Stock granite and welded tuff (Bullfrog and Tram members, Yucca Mountain, Nevada Test Site). The results of the elutions through granite agree with the matrix diffusion calculations based on independent measurements of K/sub d/. The results of the elutions through tuff, however, agree only if the K/sub d/ values used in the calculations are lower than the K/sub d/ values measured using a batch technique. This trend has been previously observed in chromatographic column experiments with tuff. 5 figures, 3 tables.« less

Feasibility of leakage detection in lake pressure pipes using the Distributed Temperature Sensing Technology

NASA Astrophysics Data System (ADS)

Apperl, Benjamin; Pressl, Alexander; Schulz, Karsten

2016-04-01

This contribution describes a feasibility study carried out in the laboratory for the detection of leakages in lake pressure pipes using high-resolution fiber-optic temperature measurements (DTS). The usage of the DTS technology provides spatiotemporal high-resolution temperature measurements along a fibre optic cable. An opto-electrical device serves both as a light emitter as well as a spectrometer for measuring the scattering of light. The fiber optic cable serves as linear sensor. Measurements can be taken at a spatial resolution of up to 25 cm with a temperature accuracy of higher than 0.1 °C. The first warmer days after the winter stagnation provoke a temperature rise of superficial layers of lakes with barely stable temperature stratification. The warmer layer in the epilimnion differs 4 °C to 5 °C compared to the cold layers in the meta- or hypolimnion before water circulation in spring starts. The warmer water from the surface layer can be rinsed on the entire length of the pipe. Water intrudes at leakages by generating a slightly negative pressure in the pipe. This provokes a local temperature change, in case that the penetrating water (seawater) differs in temperature from the water pumped through the pipe. These temperature changes should be detectable and localized with a DTS cable introduced in the pipe. A laboratory experiment was carried out to determine feasibility as well as limits and problems of this methodology. A 6 m long pipe, submerged in a water tank at constant temperature, was rinsed with water 5-10 °C warmer than the water in the tank. Temperature measurements were taken continuously along the pipe. A negative pressure of 0.1 bar provoked the intrusion of colder water from the tank into the pipe through the leakages, resulting in local temperature changes. Experiments where conducted with different temperature gradients, leakage sizes, number of leaks as well as with different positioning of the DTS cable inside the pipe. Results showed that already small leakages (4mm) can be detected. Problems have arisen from the inside positioning of DTS cable, measuring a reduced temperature difference in the transition layer at the inside wall of the pipe.

An investigation of electrohydrodynamic heat pipes

NASA Technical Reports Server (NTRS)

Loehrke, R. I.

1977-01-01

The principles of electrohydrodynamic heat pip operation are first discussed. Evaporator conductance experiments are then described. A heat pipe was designed in which grooved and ungrooved evaporator surfaces could be interchanged to evaluate the necessity of capillary grooves. Optimum electrode spacing was also studied. Finally, heat convection in evaporating thin films is considered.

Pore-water pressures associated with clogging of soil pipes: Numerical analysis of laboratory experiments

USDA-ARS?s Scientific Manuscript database

Clogging of soil pipes due to excessive internal erosion has been hypothesized to cause extreme erosion events such as landslides, debris flows, and gullies, but confirmation of this phenomenon has been lacking. Laboratory and field measurements have failed to measure pore water pressures within pip...

Soil pipe flow tracer experiments: 2. Application of a transient storage zone model

USDA-ARS?s Scientific Manuscript database

Soil pipes, defined here as discrete preferential flow paths generally parallel to the slope, are important subsurface flow pathways that play a role in many soil erosion phenomena. However, limited research has been performed on quantifying and characterizing their flow and transport characteristic...

Second-Order Chlorine Decay and Trihalomethanes Formation in a Pilot-Scale Water Distribution Systems

EPA Science Inventory

It is well known that model-building of chlorine decay in real water distribution systems is difficult because chlorine decay is influenced by many factors (e.g., bulk water demand, pipe-wall demand, piping material, flow velocity, and residence time). In this paper, experiments ...

Mineback Stimulation Research Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.

The objective of the Mineback Stimulation Research Experiments is to improve hydraulic fracture stimulation technology by providing an in situ laboratory where basic processes and mechanisms that control and influence fracture propagation can be observed, measured and understood. While previous tests have been instrumental in providing an understanding of the mechanisms controlling fracture height, current experiments are focused on fluid flow through the created fracture and the associated pressure drops and crack widths. Work performed, accomplishments and future plans are presented. 7 refs., 2 figs.

Transient Simulation of Accumulating Particle Deposition in Pipe Flow

NASA Astrophysics Data System (ADS)

Hewett, James; Sellier, Mathieu

2015-11-01

Colloidal particles that deposit in pipe systems can lead to fouling which is an expensive problem in both the geothermal and oil & gas industries. We investigate the gradual accumulation of deposited colloids in pipe flow using numerical simulations. An Euler-Lagrangian approach is employed for modelling the fluid and particle phases. Particle transport to the pipe wall is modelled with Brownian motion and turbulent diffusion. A two-way coupling exists between the fouled material and the pipe flow; the local mass flux of depositing particles is affected by the surrounding fluid in the near-wall region. This coupling is modelled by changing the cells from fluid to solid as the deposited particles exceed each local cell volume. A similar method has been used to model fouling in engine exhaust systems (Paz et al., Heat Transfer Eng., 34(8-9):674-682, 2013). We compare our deposition velocities and deposition profiles with an experiment on silica scaling in turbulent pipe flow (Kokhanenko et al., 19th AFMC, 2014).

Performance analysis of a solar still coupled with evacuated heat pipes

NASA Astrophysics Data System (ADS)

Pramod, B. V. N.; Prudhvi Raj, J.; Krishnan, S. S. Hari; Kotebavi, Vinod

2018-02-01

In developing countries the need for better quality drinking water is increasing steadily. We can overcome this need by using solar energy for desalination purpose. This process includes fabrication and analysis of a pyramid type solar still coupled with evacuated heat pipes. This experiment using evacuated heat pipes are carried in mainly three modes namely 1) Still alone 2) Using heat pipe with evacuated tubes 3)Using evacuated heat pipe. For this work single basin pyramid type solar still with 1m2 basin area is fabricated. Black stones and Black paint are utilised in solar still to increase evaporation rate of water in basin. The heat pipe’s evaporator section is placed inside evacuated tube and the heat pipe’s condenser section is connected directly to the pyramid type solar still’s lower portion. The output of distillate water from still with evacuated heat pipe is found to be 40% more than the still using only evacuated tubes.

Stirling engine external heat system design with heat pipe heater

NASA Technical Reports Server (NTRS)

Godett, Ted M.; Ziph, Benjamin

1986-01-01

This final report presents the conceptual design of a liquid fueled external heating system (EHS) and the preliminary design of a heat pipe heater for the STM-4120 Stirling cycle engine, to meet the Air Force mobile electric power (MEP) requirement for units in the range of 20 to 60 kW. The EHS design had the following constraints: (1) Packaging requirements limited the overall system dimensions to about 330 mm x 250 mm x 100 mm; (2) Heat flux to the sodium heat pipe evaporator was limited to an average of 100 kW/m and a maximum of 550 kW/m based on previous experience; and (3) The heat pipe operating temperature was specified to be 800 C based on heat input requirements of the STM4-120. An analysis code was developed to optimize the EHS performance parameters and an analytical development of the sodium heat pipe heater was performed; both are presented and discussed. In addition, construction techniques were evaluated and scale model heat pipe testing performed.

Turbulent slurry flow measurement using ultrasonic Doppler method in rectangular pipe

NASA Astrophysics Data System (ADS)

Bareš, V.; Krupička, J.; Picek, T.; Brabec, J.; Matoušek, V.

2014-03-01

Distribution of velocity and Reynolds stress was measured using ultrasonic velocimetry in flows of water and Newtonian water-ballotini slurries in a pressurized Plexiglas pipe. Profiles of the measured parameters were sensed in the vertical plane at the centreline of a rectangular cross section of the pipe. Reference measurements in clear water produced expected symmetrical velocity profiles the shape of which was affected by secondary currents developed in the rectangular pipe. Slurry-flow experiments provided information on an effect of the concentration of solid grains on the internal structure of the flow. Strong attenuation of velocity fluctuations caused by a presence of grains was identified. The attenuation increased with the increasing local concentration of the grains.

Characterization of Anisotropic Behavior for High Grade Pipes

NASA Astrophysics Data System (ADS)

Yang, Kun; Huo, Chunyong; Ji, Lingkang; Li, Yang; Zhang, Jiming; Ma, Qiurong

With the developing requirement of nature gas, the property needs of steel for pipe line are higher and higher, especially in strength and toughness. It is necessary to improve the steel grade in order to ensure economic demand and safety. However, with the rise of steel grade, the differences on properties in different orientations (anisotropic behaviors) become more and more obvious after the process of hot rolling, which may affect the prediction of fracture for the pipes seriously (Thinking of isotropic mechanical properties for material in traditional predict way). In order to get the reason for anisotropic mechanics, a series of tests are carried out for high grade steel pipes, including not only mechanical properties but also microstructures. Result indicates that there are obviously anisotropic behaviors for high grade steel pipes in two orientations (rolling orientation and transverse orientation). Strength is better in T orientation because Rm is higher and Rt 0.5 rises more in T orientation, and toughness is better in L orientation because of the higher Akv and SA in L orientation under a same temperature. Banded structures are formed in T orientation, and the spatial distribution of inclusion and precipitated phases are different in T, L and S orientation. The anisotropic arrangement for the matrix in space (banded structures), which is formed after the process of hot rolling, may affect the mechanical properties in different orientation. Moreover, the elasticity modulus of particles is different from the elasticity modulus of matrix, deformation between particles and matrix may cause stress concentration, and damage forms in this place. Because of the different distribution of particles in space, the level of damage is anisotropic in different orientations, and the anisotropic mechanical properties occur finally. Therefore, the anisotropic mechanical properties are determined by the anisotropic microstructures, both the anisotropic of matrix and the anisotropic of particles are included.

[A method for inducing standardized spiral fractures of the tibia in the animal experiment].

PubMed

Seibold, R; Schlegel, U; Cordey, J

1995-07-01

A method for the deliberate weakening of cortical bone has been developed on the basis of an already established technique for creating butterfly fractures. It enables one to create the same type of fracture, i.e., a spiral fracture, every time. The fracturing process is recorded as a force-strain curve. The results of the in vitro investigations form a basis for the preparation of experimental tasks aimed at demonstrating internal fixation techniques and their influence on the vascularity of the bone in simulated fractures. Animal protection law lays down that this fracture model must not fail in animal experiments.

A New Test Method for Determining the Strength and Fracture Toughness of Cement Mortar and Concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jy-An John; Liu, Ken C; Naus, Dan J

2010-01-01

The Spiral Notch Torsion Fracture Toughness Test (SNTT) was developed recently to determine the intrinsic fracture toughness (KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45 a pitch. KIC values are obtained with the aid of a three-dimensional finite-element computer code, TOR3D-KIC. The SNTT method is uniquely suitable for testing a wide variety of materials used extensively in pressure vessel and piping structural components and weldments. Application of the method to metallic, ceramic, and graphite materials has been demonstrated. One importantmore » characteristic of SNTT is that neither a fatigue precrack or a deep notch are required for the evaluation of brittle materials, which significantly reduces the sample size requirement. In this paper we report results for a Portland cement-based mortar to demonstrate applicability of the SNTT method to cementitious materials. The estimated KIC of the tested mortar samples with compressive strength of 34.45 MPa was found to be 0.19 MPa m^(1/2).« less

Mixing at double-Tee junctions with unequal pipe sizes in ...

EPA Pesticide Factsheets

Pipe flow mixing with various solute concentrations and flow rates at pipe junctions is investigated. The degree of mixing affects the spread of contaminants in a water distribution system. Many studies have been conducted on the mixing at the cross junctions. Yet a few have focused on double-Tee junctions of unequal pipe sizes. To investigate the solute mixing at double-Tee junctions with unequal pipe sizes, a series of experiments were conducted in a turbulent regime (Re=12500–50000) with different Reynolds number ratios and connecting pipe lengths. It is shown that dimensionless outlet concentrations depended on mixing mechanism at the impinging interface of junctions. Junction with a larger pipe size ratio is associated with more complete mixing. The inlet Reynolds number ratio affects mixing more strongly than the outlet Reynolds number ratio. Furthermore, the dimensionless connecting pipe length in a double-Tee played an important and complicated role in the flow mixing. Based on these results, two-dimensional isopleth maps were developed for the calculation of normalized north outlet concentration. This journal article is to communicate the research results on pipe juncture mixing, a widespread and important phenomena in distribution system water quality analysis. The research outcome improves EPANET modeling capability for safe water supplies. In addition, the research is one of the outputs from the EPA-MOST bilateral cooperative research Project #1

Effect of PVC and iron materials on Mn(II) deposition in drinking water distribution systems.

PubMed

Cerrato, José M; Reyes, Lourdes P; Alvarado, Carmen N; Dietrich, Andrea M

2006-08-01

Polyvinyl chloride (PVC) and iron pipe materials differentially impacted manganese deposition within a drinking water distribution system that experiences black water problems because it receives soluble manganese from a surface water reservoir that undergoes biogeochemical cycling of manganese. The water quality study was conducted in a section of the distribution system of Tegucigalpa, Honduras and evaluated the influence of iron and PVC pipe materials on the concentrations of soluble and particulate iron and manganese, and determined the composition of scales formed on PVC and iron pipes. As expected, total Fe concentrations were highest in water from iron pipes. Water samples obtained from PVC pipes showed higher total Mn concentrations and more black color than that obtained from iron pipes. Scanning electron microscopy demonstrated that manganese was incorporated into the iron tubercles and thus not readily dislodged from the pipes by water flow. The PVC pipes contained a thin surface scale consisting of white and brown layers of different chemical composition; the brown layer was in contact with the water and contained 6% manganese by weight. Mn composed a greater percentage by weight of the PVC scale than the iron pipe scale; the PVC scale was easily dislodged by flowing water. This research demonstrates that interactions between water and the infrastructure used for its supply affect the quality of the final drinking water.

Crystal structures of resorcin[4]arene and pyrogallol[4]arene complexes with DL-pipecolinic acid. Model compounds for the recognition of the pipecolinyl ring, a key fragment of FK506, through C-H⋯π interaction

NASA Astrophysics Data System (ADS)

Fujisawa, Ikuhide; Kitamura, Yuji; Kato, Ryo; Murayama, Kazutaka; Aoki, Katsuyuki

2014-01-01

Resorcin[4]arene (resorcinol cyclic tetramer, abbreviated as RCT) or pyrogallol[4]arene (pyrogallol cyclic tetramer, PCT) form host-guest 1:1 complexes with DL-pipecolinic acid (DL-pipeH), RCT·DL-pipeH·EtOH·8H2O (1), PCT DL-pipeH·EtOH·4H2O (2), and PCT·DL-pipeH·3H2O (3), whose crystal structures have been determined. In each complex, the pipeH ligand is incorporated into the bowl-shaped cavity of the RCT or PCT host molecules through C-H⋯π interactions between alkyl protons of the piperidine ring of pipeH and π-rings of RCT or PCT, forming an [(RCT/PCT)·pipeH] structural fragment. In 1 and 3, two [(RCT/PCT) pipeH] fragments self-associate across an inversion center to form a guest-mediated, obliquely declined dimeric structure [(RCT/PCT)·L-pipeH·D-pipeH (RCT/PCT)]. In 2, each PCT-capped pipeH ligand bridges to two adjacent PCT molecules to form guest-mediated, optically-discrete helical polymers [PCT·L-pipeH]n or [PCT·D-pipeH]n. An 1H NMR experiment shows that the complexation through C-H⋯π interaction between the piperidine ring of pipeH and π-rings of RCT or PCT occurs also in solution, with the binding constants of 9.7 ± 0.6 M-1 for RCT and 26.5 ± 1.5 M-1 for PCT. These complexes provide a synthetic model for the recognition of the pipecolinyl-ring moiety, a key constituent of immunosuppressant drugs such as FK506, FK520 or rapamycin, by their binding proteins through C-H⋯π interaction.

Chlorine fate and transport in drinking water distribution systems: Results from experimental and modeling studies

NASA Astrophysics Data System (ADS)

Clark, Robert M.

2011-12-01

It has become generally accepted that water quality can deteriorate in a distribution system through microbiological and chemical reactions in the bulk phase and/or at the pipe wall. The most serious aspect of water quality deterioration in a network is the loss of the disinfectant residual that can weaken the barrier against microbial contamination. Studies have suggested that one factor contributing to the loss of disinfectant residuals is the reaction between bulk phase disinfectants and pipe wall material. Free chlorine loss in corroded metal and PVC pipes, subject to changes in velocity, was assessed during an experiment conducted under controlled conditions in a specially constructed pipe loop located at the US Environmental Protection Agency's (EPA's) Test and Evaluation (T&E) Facility in Cincinnati, Ohio (USA). These studies demonstrated that in older unlined metal pipes, the loss of chlorine residual increases with velocity but that wall demand in PVC was negligible.

Intrusion of Soil Water through Pipe Cracks

EPA Science Inventory

This report describes a series of experiments conducted at U.S. EPA’s Test and Evaluation Facility in 2013-2014 to study the intrusion of contaminated soil water into a pipe crack during simulated backflow events. A test rig was used consisting of a 3’ x 3’ x 3’ acrylic soil bo...

Laminar Flow Breakdown due to Particle Interactions

DTIC Science & Technology

2012-08-01

theoretically predicted value of 200x106 in a heated pipe flow experiment – a fact which they attributed to naturally occurring particulates contained in the...the pipe wall, y, to boundary layer thickness, δ, reproduced from Hall [10...12 Figure 5 Estimated critical particle conditions on a heated laminar flow control body at three heating

Experiments on rehabilitation of radioactive metallic waste (RMW) of reactor stainless steels of Siberian chemical plant

NASA Astrophysics Data System (ADS)

Kolpakov, G. N.; Zakusilov, V. V.; Demyanenko, N. V.; Mishin, A. S.

2016-06-01

Stainless steel pipes, used to cool a reactor plant, have a high cost, and after taking a reactor out of service they must be buried together with other radioactive waste. Therefore, the relevant problem is the rinse of pipes from contamination, followed by returning to operation.

Startup of a frozen heat pipe in one-g and micro-g environments - A proposed shuttle flight experiment

NASA Technical Reports Server (NTRS)

Ochterbeck, J. M.; Peterson, G. P.

1991-01-01

An attempt is made to determine how a heat pipe freezes under various low load and/or no load conditions in both one-g and micro-g environments. Also of interest are the mechanisms that can be used to restart the heat pipe after freezing has occurred. Particular attention is given to step function power reductions and the resulting distribution of the working fluid after freezing has occurred and the effect of noncondensible gases on the frozen configuration and the restart characteristics.

Experimental and Theoretical Research on the Compression Performance of CFRP Sheet Confined GFRP Short Pipe

PubMed Central

Zhao, Qilin; Chen, Li; Shao, Guojian

2014-01-01

The axial compressive strength of unidirectional FRP made by pultrusion is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. A theoretical iterative calculation approach was suggested to predict the ultimate axial compressive stress of the combined structure and analyze the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure. In this paper, the experimental and theoretical research on the CFRP sheet confined GFRP short pole was extended to the CFRP sheet confined GFRP short pipe, namely, a hollow section pole. Experiment shows that the bearing capacity of the GFRP short pipe can also be heightened obviously by confining CFRP sheet. The theoretical iterative calculation approach in the previous paper is amended to predict the ultimate axial compressive stress of the CFRP sheet confined GFRP short pipe, of which the results agree with the experiment. Lastly the influences of geometrical parameters on the new combined structure are analyzed. PMID:24672288

Construction and 1st Experiment of the 500-meter and 1000-meter DC Superconducting Power Cable in Ishikari

NASA Astrophysics Data System (ADS)

Yamaguchi, S.; Ivanov, Y.; Watanabe, H.; Chikumoto, N.; Koshiduka, H.; Hayashi, K.; Sawamura, T.

Ishikari project constructs two lines. The length of the Line 1 is 500 m, and connects the photovoltaic cell to the internet-data center. The other line is 1 km length, and it is a test facility and called Line 2. The structures of the cable systems are not same to test their performance. The construction was started from 2014 in the field, the Line 1 was completed in May 2015, and it was cooled down and do the current experiment, and warmed up. The Line 2 is almost complete in October 2015. It will be tested in November and December, 2015. In order to reduce the stress of the cable induced by the thermal expansion and contraction, we adopted the way of the helical deformation of the cable. The force of the cable is reduced to 1/3 of an usual cable test. Because the cryogenic pipes are welded in the field and we cannot use the baking of the vacuum chamber of the cryogenic pipe, a new vacuum pumping method was proposed and tested for the cryogenic pipe. Since the straight pipes are used to compose the cryogenic pipe, the pressure drop of the circulation would be 1/100 of the corrugated pipe in the present condition, and it is suitable for longer cable system. The heat leak of the cryogenic pipe is ∼1.4W/m including the cable pipe's and the return pipe's. The heat leak of the current lead is ∼30W/kA in the test bench. Finally the current of 6kA/3 sec and the current of 5kA/15 min were achieved in Line 1. The reduction of heat leak will be a major subject of the longer cable system. The cost of the construction will be almost twice higher than that of the copper and aluminum over-head line with the iron tower in the present Japan. The cost construction of the over-head line is an average value, and depends on the newspaper.

A Review of Large-Scale Fracture Experiments Relevant to Pressure Vessel Integrity Under Pressurized Thermal Shock Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pugh, C.E.

2001-01-29

Numerous large-scale fracture experiments have been performed over the past thirty years to advance fracture mechanics methodologies applicable to thick-wall pressure vessels. This report first identifies major factors important to nuclear reactor pressure vessel (RPV) integrity under pressurized thermal shock (PTS) conditions. It then covers 20 key experiments that have contributed to identifying fracture behavior of RPVs and to validating applicable assessment methodologies. The experiments are categorized according to four types of specimens: (1) cylindrical specimens, (2) pressurized vessels, (3) large plate specimens, and (4) thick beam specimens. These experiments were performed in laboratories in six different countries. This reportmore » serves as a summary of those experiments, and provides a guide to references for detailed information.« less

Fracture behavior of the Space Shuttle thermal protection system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komine, A.; Kobayashi, A.S.

1983-09-01

Stable crack-growth and fracture-toughness experiments were conducted using precracked specimens machined from LI-900 reusable surface insulation (RSI) tiles of the Space Shuttle thermal protection system (TPS) at room temperature. Similar fracture experiments were conducted on fracture specimens with preexisting cracks at the interface of the tile and the strain isolation pad (SIP). Stable crack growth was not observed in the LI-900 tile fracture specimens which had a fracture toughness of 12.0 kPa sq rt of m. The intermittent subcritical crack growth at the tile-pad interface of the fracture specimens was attributed to successive local pull-outs due to tensile overload inmore » the LI-900 tile and cannot be characterized by linear elastic fracture mechanics. No subcritical interfacial crack growth was observed in the fracture specimens with densified LI-900 tiles where brittle fracture initiated at an interior point away from the densification. 11 references.« less

Applications of UT results to confirm defects findings by utilization of relevant metallurgical investigations techniques on gas/condensate pipeline working in wet sour gas environment

NASA Astrophysics Data System (ADS)

El-Azhari, O. A.; Gajam, S. Y.

2015-03-01

The gas/condensate pipe line under investigation is a 12 inch diameter, 48 km ASTM, A106 steel pipeline, carrying hydrocarbons containing wet CO2 and H2S.The pipe line had exploded in a region 100m distance from its terminal; after 24 years of service. Hydrogen induced cracking (HIC) and sour gas corrosion were expected due to the presence of wet H2S in the gas analysis. In other areas of pipe line ultrasonic testing was performed to determine whether the pipeline can be re-operated. The results have shown presence of internal planner defects, this was attributed to the existence of either laminations, type II inclusions or some service defects such as HIC and step wise cracking (SWC).Metallurgical investigations were conducted on fractured samples as per NACE standard (TM-0284-84). The obtained results had shown macroscopic cracks in the form of SWC, microstructure of steel had MnS inclusions. Crack sensitivity analyses were calculated and the microhardness testing was conducted. These results had confirmed that the line material was suffering from sour gas deteriorations. This paper correlates the field UT inspection findings with those methods investigated in the laboratory. Based on the results obtained a new HIC resistance material pipeline needs to be selected.

TOUGH-RBSN simulator for hydraulic fracture propagation within fractured media: Model validations against laboratory experiments

NASA Astrophysics Data System (ADS)

Kim, Kunhwi; Rutqvist, Jonny; Nakagawa, Seiji; Birkholzer, Jens

2017-11-01

This paper presents coupled hydro-mechanical modeling of hydraulic fracturing processes in complex fractured media using a discrete fracture network (DFN) approach. The individual physical processes in the fracture propagation are represented by separate program modules: the TOUGH2 code for multiphase flow and mass transport based on the finite volume approach; and the rigid-body-spring network (RBSN) model for mechanical and fracture-damage behavior, which are coupled with each other. Fractures are modeled as discrete features, of which the hydrological properties are evaluated from the fracture deformation and aperture change. The verification of the TOUGH-RBSN code is performed against a 2D analytical model for single hydraulic fracture propagation. Subsequently, modeling capabilities for hydraulic fracturing are demonstrated through simulations of laboratory experiments conducted on rock-analogue (soda-lime glass) samples containing a designed network of pre-existing fractures. Sensitivity analyses are also conducted by changing the modeling parameters, such as viscosity of injected fluid, strength of pre-existing fractures, and confining stress conditions. The hydraulic fracturing characteristics attributed to the modeling parameters are investigated through comparisons of the simulation results.

Evolution of turbulence characteristics from straight to curved pipes

NASA Astrophysics Data System (ADS)

El Khoury, George K.; Noorani, Azad; Schlatter, Philipp; Fischer, Paul F.

2012-11-01

Large-scale direct numerical simulations are performed to study turbulent flow in straight and bent pipes at four different Reynolds numbers: Reb = 5300 , 11700 (bent and straight) and 19000 and 37700 (only straight). We consider a pipe of radius R and axial length 25 R with curvature parameter κ taken to be 0 , 0 . 01 and 0 . 1 for zero, mild and strong curvatures, respectively. The code used is Nek5000 based on the spectral element method. In the straight configuration, the obtained DNS data is carefully checked against other recent simulations, highlighting minute differences between the available data. Owing to a centrifugal instability mechanism, the flow in bent pipe (κ ≠ 0) develops counter-rotating vortices, so-called Dean vortices. The presence of the secondary motion thus induces substantial asymmetries both in the mean flow and turbulence characteristics for the bent pipe. These asymmetries tend to damp turbulence along the inner side and correspondingly enhance it along the upper side. The results are validated with recent experiments, and we could confirm the peculiar behaviour of the friction factor for specific curvatures and Re , leading to a lower friction in curved pipes than in straight pipes for the same mass flux.

Evaluation of ground-penetrating radar to detect free-phase hydrocarbons in fractured rocks - Results of numerical modeling and physical experiments

USGS Publications Warehouse

Lane, J.W.; Buursink, M.L.; Haeni, F.P.; Versteeg, R.J.

2000-01-01

The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.The suitability of common-offset ground-penetrating radar (GPR) to detect free-phase hydrocarbons in bedrock fractures was evaluated using numerical modeling and physical experiments. The results of one- and two-dimensional numerical modeling at 100 megahertz indicate that GPR reflection amplitudes are relatively insensitive to fracture apertures ranging from 1 to 4 mm. The numerical modeling and physical experiments indicate that differences in the fluids that fill fractures significantly affect the amplitude and the polarity of electromagnetic waves reflected by subhorizontal fractures. Air-filled and hydrocarbon-filled fractures generate low-amplitude reflections that are in-phase with the transmitted pulse. Water-filled fractures create reflections with greater amplitude and opposite polarity than those reflections created by air-filled or hydrocarbon-filled fractures. The results from the numerical modeling and physical experiments demonstrate it is possible to distinguish water-filled fracture reflections from air- or hydrocarbon-filled fracture reflections, nevertheless subsurface heterogeneity, antenna coupling changes, and other sources of noise will likely make it difficult to observe these changes in GPR field data. This indicates that the routine application of common-offset GPR reflection methods for detection of hydrocarbon-filled fractures will be problematic. Ideal cases will require appropriately processed, high-quality GPR data, ground-truth information, and detailed knowledge of subsurface physical properties. Conversely, the sensitivity of GPR methods to changes in subsurface physical properties as demonstrated by the numerical and experimental results suggests the potential of using GPR methods as a monitoring tool. GPR methods may be suited for monitoring pumping and tracer tests, changes in site hydrologic conditions, and remediation activities.

Investigating the Capabilities of Ground Penetrating Radar for Imaging Shallow Experimental Fractures

NASA Astrophysics Data System (ADS)

Dogan, M.; Moysey, S. M.; Murdoch, L. C.; Denison, J. L. S.; Ahmadian, M.

2017-12-01

We have used ground penetrating radar (GPR) to image fractures formed in shallow sediments as a result of high-pressure injection. Understanding fracture formation and behavior is important for a variety of reasons, ranging from validating fracture formation theories to characterizing fracture networks induced for enhancing recovery schemes in low permeability rocks. GPR is a high resolution geophysical method that is sensitive to electromagnetic property changes in the subsurface. The resolution of GPR is, however, typically on the order of ¼ of the wavelength, which for the 900MHz GPR data is on the order of 2-5cm. Thus it was not clear prior to the experiment whether it would be possible for GPR to image the fractures formed during the injection. We found that the GPR was indeed able to image the fractures very well as they evolved through time. Over the course of the experiment, we were able to collect pseudo-3D data that allowed us to monitor the growth of the fracture over time. The experiment was also repeated for different injection materials to examine how the fill in the fractures impacts the GPR signal. From the GPR data we are able to reconstruct the approximate three-dimensional shape of the facture over time. At the end of the experiment, the experimental cells were trenched so that the actual fracture distribution could be mapped. Overall, the GPR interpretation showed reasonable agreement with what we could observed in the trenches. The experimental results suggest that GPR characterization of fractures is feasible.

Modeling of the Edwards pipe experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tiselj, I.; Petelin, S.

1995-12-31

The Edwards pipe experiment is used as one of the basic benchmarks for the two-phase flow codes due to its simple geometry and the wide range of phenomena that it covers. Edwards and O`Brien filled 4-m-long pipe with liquid water at 7 MPa and 502 K and ruptured one end of the tube. They measured pressure and void fraction during the blowdown. Important phenomena observed were pressure rarefaction wave, flashing onset, critical two-phase flow, and void fraction wave. Experimental data were used to analyze the capabilities of the RELAP5/MOD3.1 six-equation two-phase flow model and to examine two different numerical schemes:more » one from the RELAP5/MOD3.1 code and one from our own code, which was based on characteristic upwind discretization.« less

Assessment of Surrogate Fractured Rock Networks for Evidence of Complex Behavior

NASA Astrophysics Data System (ADS)

Wood, T. R.; McJunkin, T. R.; Podgorney, R. K.; Glass, R. J.; Starr, R. C.; Stoner, D. L.; Noah, K. S.; LaViolette, R. A.; Fairley, J.

2001-12-01

A complex system or complex process is -"one whose properties are not fully explained by an understanding of its component parts". Results from field experiments conducted at the Hell's Half-Acre field site (Arco, Idaho) suggest that the flow of water in an unsaturated, fractured medium exhibits characteristics of a complex process. A series of laboratory studies is underway with sufficient rigor to determine if complex behavior observed in the field is in fact a fundamental characteristic of water flow in unsaturated, fractured media. As an initial step, a series of four duplicate experiments has been performed using an array of bricks to simulate fractured, unsaturated media. The array consisted of 12 limestone blocks cut to uniform size (5cm x 7 cm x 30 cm) stacked on end 4 blocks wide and 3 blocks high with the interfaces between adjacent blocks representing 3 vertical fractures intersecting 2 horizontal fractures. Water was introduced at three point sources on the upper boundary of the model at the top of the vertical fractures. Water was applied under constant flux at a rate below the infiltration capacity of the system, thus maintaining unsaturated flow conditions. Water was collected from the lower boundary via fiberglass wicks at the bottom of each fracture. An automated system acquired and processed water inflow and outflow data and time-lapse photographic data during each of the 72-hour tests. From these experiments, we see that a few general statements can be made on the overall advance of the wetting front in the surrogate fracture networks. For instance, flow generally converged with depth to the center fracture in the bottom row of bricks. Another observation is that fracture intersections integrate the steady flow in overlying vertical fractures and allow or cause short duration high discharge pulses or "avalanches" of flow to quickly traverse the fracture network below. Smaller scale tests of single fracture and fracture intersections are underway to evaluate a wide array of unit processes that are believed to contribute to complex behavior. Examples of these smaller scale experiments include the role of fracture intersections in integrating a steady inflow to generate giant fluctuations in network discharge; the influence of microbe growth on flow; and the role of geochemistry in alterations of flow paths. Experiments are planned at the meso and field scale to document and understand the controls on self-organized behavior. Modeling is being conducted in parallel with the experiments to understand how simulations can be improved to capture the complexity of fluid flow in fractured rock vadose zones and to make better predictions of contaminant transport.

Guided wave radiation from a point source in the proximity of a pipe bend

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brath, A. J.; Nagy, P. B.; Simonetti, F.

Throughout the oil and gas industry corrosion and erosion damage monitoring play a central role in managing asset integrity. Recently, the use of guided wave technology in conjunction with tomography techniques has provided the possibility of obtaining point-by-point maps of wall thickness loss over the entire volume of a pipeline section between two ring arrays of ultrasonic transducers. However, current research has focused on straight pipes while little work has been done on pipe bends which are also the most susceptible to developing damage. Tomography of the bend is challenging due to the complexity and computational cost of the 3-Dmore » elastic model required to accurately describe guided wave propagation. To overcome this limitation, we introduce a 2-D anisotropic inhomogeneous acoustic model which represents a generalization of the conventional unwrapping used for straight pipes. The shortest-path ray-tracing method is then applied to the 2-D model to compute ray paths and predict the arrival times of the fundamental flexural mode, A0, excited by a point source on the straight section of pipe entering the bend and detected on the opposite side. Good agreement is found between predictions and experiments performed on an 8” diameter (D) pipe with 1.5 D bend radius. The 2-D model also reveals the existence of an acoustic lensing effect which leads to a focusing phenomenon also confirmed by the experiments. The computational efficiency of the 2-D model makes it ideally suited for tomography algorithms.« less

A simple hydrodynamic model of a laminar free-surface jet in horizontal or vertical flight

NASA Astrophysics Data System (ADS)

Haustein, Herman D.; Harnik, Ron S.; Rohlfs, Wilko

2017-08-01

A useable model for laminar free-surface jet evolution during flight, for both horizontal and vertical jets, is developed through joint analytical, experimental, and simulation methods. The jet's impingement centerline velocity, recently shown to dictate stagnation zone heat transfer, encompasses the entire flow history: from pipe-flow velocity profile development to profile relaxation and jet contraction during flight. While pipe-flow is well-known, an alternative analytic solution is presented for the centerline velocity's viscous-driven decay. Jet-contraction is subject to influences of surface tension (We), pipe-flow profile development, in-flight viscous dissipation (Re), and gravity (Nj = Re/Fr). The effects of surface tension and emergence momentum flux (jet thrust) are incorporated analytically through a global momentum balance. Though emergence momentum is related to pipe flow development, and empirically linked to nominal pipe flow-length, it can be modified to incorporate low-Re downstream dissipation as well. Jet contraction's gravity dependence is extended beyond existing uniform-velocity theory to cases of partially and fully developed profiles. The final jet-evolution model relies on three empirical parameters and compares well to present and previous experiments and simulations. Hence, micro-jet flight experiments were conducted to fill-in gaps in the literature: jet contraction under mild gravity-effects, and intermediate Reynolds and Weber numbers (Nj = 5-8, Re = 350-520, We = 2.8-6.2). Furthermore, two-phase direct numerical simulations provided insight beyond the experimental range: Re = 200-1800, short pipes (Z = L/d . Re ≥ 0.01), variable nozzle wettability, and cases of no surface tension and/or gravity.

Investigation of the Effect of Cemented Fractures on Fracturing Network Propagation in Model Block with Discrete Orthogonal Fractures

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, C. H.

2017-07-01

Researchers have recently realized that the natural fractures in shale reservoirs are often cemented or sealed with various minerals. However, the influence of cement characteristics of natural fracture on fracturing network propagation is still not well understood. In this work, laboratory-scaled experiments are proposed to prepare model blocks with discrete orthogonal fractures network with different strength of natural fracture, in order to reveal the influence of cemented natural fractures on the interactions between hydraulic fractures and natural fractures. A series of true triaxial hydraulic fracturing experiments were conducted to investigate the mechanism of hydraulic fracture initiation and propagation in model blocks with natural fractures of different cement strength. The results present different responses of interactions between hydraulic and natural fractures, which can be reflected on the pump pressure profiles and block failure morphology. For model blocks with fluctuated pump pressure curves, the communication degree of hydraulic and natural fractures is good, which is confirmed by a proposed new index of "P-SRV." The most significant finding is that too high and too low strength properties of cemented natural fracture are adverse to generate complex fracturing network. This work can help us better understand how cemented natural fractures affect the fracturing network propagation subsurface and give us reference to develop more accurate hydraulic fracturing models.

Pain and fracture-related limitations persist 6 months after a fragility fracture.

PubMed

Sale, Joanna E M; Frankel, Lucy; Thielke, Stephen; Funnell, Larry

2017-08-01

Our objective was to examine the experience of pain after a fracture beyond the conventional healing duration of 6 months. We conducted a phenomenological study in participants who were deemed high risk for future fracture and recruited through an urban fracture clinic in Toronto, Canada. In-depth interviews were conducted with questions addressing the experience of pain, the status of recovery from the fracture, ways in which the fracture affected one's daily activities, and interactions with health care providers. Two researchers coded the transcripts within the phenomenological perspective to develop a structure of the pain experience, promoting rigour through the use of multiple analysts, searching for negative cases, and supporting claims with direct quotations from participants. We interviewed 21 participants who had sustained fractures of the wrist (n = 4), hip (n = 6), vertebrae (n = 2), and multiple or other locations (n = 9). All patients were ambulatory, had a range of socioeconomic status, and lived in the community. Eleven of the 21 participants reported persistent pain at the site of the fracture. Of the 10 participants who reported no pain, four indicated they had ongoing difficulties with range of motion and specific activities and two others described persistent pain from a previous fracture or reliance on a scooter for mobility. Our study demonstrated that over two-thirds of older adults reported fracture-related pain and/or limitations at, or beyond, 6 months post-fracture. We suggest that health care providers ask questions about post-fracture pain and/or limitations when assessing fracture status beyond 6 months.

An Experimental Study of Contaminant Intrusion Through Pipe Cracks

EPA Science Inventory

This report describes a series of experiments conducted at U.S. EPA’s Test and Evaluation Facility in 2013-2014 to study the intrusion of contaminated soil water into a pipe crack during simulated backflow events. A test rig was used consisting of a 3’ x 3’ x 3’ acrylic soil bo...

PECASE - Multi-Scale Experiments and Modeling in Wall Turbulence

DTIC Science & Technology

2014-12-23

transition to turbulence in pipe flow have been characterized by the creation of puffs and slugs [Wygnanski and Champagne , 1973]. Puffs have been identified...Fluid Mech., 568:55–76, 2006. I. J. Wygnanski and F. H. Champagne . On transition in a pipe. Part 1: The origin of puffs and slugs and the flow in a

Autogenous Metallic Pipe Leak Repair in Potable Water Systems.

PubMed

Tang, Min; Triantafyllidou, Simoni; Edwards, Marc A

2015-07-21

Copper and iron pipes have a remarkable capability for autogenous repair (self-repair) of leaks in potable water systems. Field studies revealed exemplars that metallic pipe leaks caused by nails, rocks, and erosion corrosion autogenously repaired, as confirmed in the laboratory experiments. This work demonstrated that 100% (N = 26) of 150 μm leaks contacting representative bulk potable water in copper pipes sealed autogenously via formation of corrosion precipitates at 20-40 psi, pH 3.0-11.0, and with upward and downward leak orientations. Similar leaks in carbon steel pipes at 20 psi self-repaired at pH 5.5 and 8.5, but two leaks did not self-repair permanently at pH 11.0 suggesting that water chemistry may control the durability of materials that seal the leaks and therefore the permanence of repair. Larger 400 μm holes in copper pipes had much lower (0-33%) success of self-repair at pH 3.0-11.0, whereas all 400 μm holes in carbon steel pipes at 20 psi self-repaired at pH 4.0-11.0. Pressure tests indicated that some of the repairs created at 20-40 psi ambient pressure could withstand more than 100 psi without failure. Autogenous repair has implications for understanding patterns of pipe failures, extending the lifetime of decaying infrastructure, and developing new plumbing materials.

Experimental and theoretical analysis on the effect of inclination on metal powder sintered heat pipe radiator with natural convection cooling

NASA Astrophysics Data System (ADS)

Cong, Li; Qifei, Jian; Wu, Shifeng

2017-02-01

An experimental study and theoretical analysis of heat transfer performance of a sintered heat pipe radiator that implemented in a 50 L domestic semiconductor refrigerator have been conducted to examine the effect of inclination angle, combined with a minimum entropy generation analysis. The experiment results suggest that inclination angle has influences on both the evaporator and condenser section, and the performance of the heat pipe radiator is more sensitive to the inclination change in negative inclined than in positive inclined position. When the heat pipe radiator is in negative inclination angle position, large amplitude of variation on the thermal resistance of this heat pipe radiator is observed. As the thermal load is below 58.89 W, the influence of inclination angle on the overall thermal resistance is not that apparent as compared to the other three thermal loads. Thermal resistance of heat pipe radiator decreases by 82.86 % in inclination of 60° at the set of 138.46 W, compared to horizontal position. Based on the analysis results in this paper, in order to achieve a better heat transfer performance of the heat pipe radiator, it is recommended that the heat pipe radiator be mounted in positive inclination angle positions (30°-90°), where the condenser is above the evaporator.

Measuring a state of mind indicative of thriving using the Student Pharmacist Inventory of Professional Engagement (S-PIPE).

PubMed

Aronson, Benjamin D; Janke, Kristin K

2018-07-01

Professional engagement has importance to the professional of pharmacy, and in particular the growth of student pharmacists. Measurement of this construct would allow investigation of factors that may increase or decrease professional engagement. To describe the development of the Student Pharmacist Inventory of Professional Engagement (S-PIPE), assess the factor structure and convergent validity, and test for differences in professional engagement based upon demographic and background factors. Potential items for the S-PIPE were developed iteratively through inductive and deductive item-writing, 2 pilot administrations, expert review of items, and assessment of the content validity index, and cognitive interviews with students. The S-PIPE was administered to a cohort of 164 first year student pharmacists at University of Minnesota, along with items querying types and level of involvement in professional experiences and activities. An exploratory factor analysis was conducted using principal axis factoring extraction and Promax rotation. The number of factors to retain was based upon eigenvalues, examination of the scree plot, and a parallel analysis. Factors of the S-PIPE were compared to self-rated level of involvement and other demographic factors. Three factors were retained accounting for 70.7% of the variance, and named Belonging (α = 0.942, 9 items), Connectedness (α = 0.864, 3 items), and Meaningful Experience (α = 0.760, 4 items). All 3 factors were significantly correlated to self-rated involvement (r = 0.291 to 0.370). Level of professional engagement differed in this study by gender, and pharmacy work experience. This study lays the foundation for quantitative research in professional engagement among student pharmacists. Future work is needed to further validate and extend these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

A review of the multiwell experiment in tight gas sandstones of the Mesaverde Group, Piceance Basin, Colorado

USGS Publications Warehouse

Nelson, P.H.

2002-01-01

The Cretaceous Iles and Williams Fork Formations of the Mesaverde Group contain important reservoir and source rocks for basin-centered gas accumulations in the Piceance Basin of northwestern Colorado. The sandstones in these formations have very low permeability, so low that successful production of gas requires the presence of fractures. To increase gas production, the natural fracture system of these "tight gas sandstones" must be augmented by inducing artificial fractures, while minimizing the amount of formation damage due to introduced fluids. The Multiwell Experiment was undertaken to provide geological characterization, obtain physical property data, and perform stimulation experiments in the Iles and Williams Fork Formations. Three vertical wells and one follow-up slant well were drilled, logged, partially cored, tested for gas production, stimulated in various manners, and tested again. Drawing from published reports and papers, this review paper presents well log, core, and test data from the Multiwell Experiment while emphasizing the geological controls on gas production at the site. Gas production is controlled primarily by a set of regional fractures trending west-northwest. The fractures are vertical, terminating at lithologic boundaries within and at the upper and lower boundaries of sandstone beds. Fractures formed preferentially in sandstones where in situ stress and fracture gradients are lower than in shales and mudstones. The fractures cannot be identified adequately in vertical wellbores; horizontal wells are required. Because present-day maximum horizontal stress is aligned with the regional fractures, artificial fractures induced by pressuring the wellbore form parallel to the regional fractures rather than linking them, with consequent limitations upon enhancement of gas production.

Flow and fracturing of viscoelastic media under diffusion-driven bubble growth: An analogue experiment for eruptive volcanic conduits

NASA Astrophysics Data System (ADS)

Taddeucci, J.; Spieler, O.; Ichihara, M.; Dingwell, D. B.; Scarlato, P.

2006-03-01

To visualize the behavior of erupting magma in volcanic conduits, we performed shock tube experiments on the ductile-brittle response of a viscoelastic medium to diffusion-driven bubble expansion. A sample of shear-thinning magma analogue is saturated by gas Ar under high pressure. On rapid decompression, Ar supersaturation causes bubbles to nucleate, grow, and coalesce in the sample, forcing it to expand, flow, and fracture. Experimental variables include saturation pressure and duration, and shape and lubrication of the flow path. Bubble growth in the experiments controls both flow and fracturing, and is consistent with physical models of magma vesiculation. Two types of fractures are observed: i) sharp fractures along the uppermost rim of the sample, and ii) fractures pervasively diffused throughout the sample. Rim fractures open when shear stress accumulates and strain rate is highest at the margin of the flow (a process already inferred from observations and models to occur in magma). Pervasive fractures originate when wall-friction retards expansion of the sample, causing pressure to build-up in the bubbles. When bubble pressure overcomes wall-friction and the tensile strength of the porous sample, fractures open with a range of morphologies. Both types of fracture open normally to flow direction, and both may heal as the flow proceeds. These experiments also illustrate how the development of pervasive fractures allows exsolving gas to escape from the sample before the generation of a permeable network via other processes, e.g., bubble coalescence. This is an observation that potentially impact the degassing of magma and the transition between explosive and effusive eruptions.

Physical simulation study on the hydraulic fracture propagation of coalbed methane well

NASA Astrophysics Data System (ADS)

Wu, Caifang; Zhang, Xiaoyang; Wang, Meng; Zhou, Longgang; Jiang, Wei

2018-03-01

As the most widely used technique to modify reservoirs in the exploitation of unconventional natural gas, hydraulic fracturing could effectively raise the production of CBM wells. To study the propagation rules of hydraulic fractures, analyze the fracture morphology, and obtain the controlling factors, a physical simulation experiment was conducted with a tri-axial hydraulic fracturing test system. In this experiment, the fracturing sample - including the roof, the floor, and the surrounding rock - was prepared from coal and similar materials, and the whole fracturing process was monitored by an acoustic emission instrument. The results demonstrated that the number of hydraulic fractures in coal is considerably higher than that observed in other parts, and the fracture morphology was complex. Vertical fractures were interwoven with horizontal fractures, forming a connected network. With the injection of fracturing fluid, a new hydraulic fracture was produced and it extended along the preexisting fractures. The fracture propagation was a discontinuous, dynamic process. Furthermore, in-situ stress plays a key role in fracture propagation, causing the fractures to extend in a direction perpendicular to the minimum principal stress. To a certain extent, the different mechanical properties of the coal and the other components inhibited the vertical propagation of hydraulic fractures. Nonetheless, the vertical stress and the interfacial property are the major factors to influence the formation of the "T" shaped and "工" shaped fractures.

The protein information and property explorer: an easy-to-use, rich-client web application for the management and functional analysis of proteomic data

PubMed Central

Ramos, H.; Shannon, P.; Aebersold, R.

2008-01-01

Motivation: Mass spectrometry experiments in the field of proteomics produce lists containing tens to thousands of identified proteins. With the protein information and property explorer (PIPE), the biologist can acquire functional annotations for these proteins and explore the enrichment of the list, or fraction thereof, with respect to functional classes. These protein lists may be saved for access at a later time or different location. The PIPE is interoperable with the Firegoose and the Gaggle, permitting wide-ranging data exploration and analysis. The PIPE is a rich-client web application which uses AJAX capabilities provided by the Google Web Toolkit, and server-side data storage using Hibernate. Availability: http://pipe.systemsbiology.net Contact: pshannon@systemsbiology.org PMID:18635572

Influence of natural fractures on hydraulic fracture propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principal in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur.« less

Influence of natural fractures on hydraulic fracture propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teufel, L.W.; Warpinski, N.R.

Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principle in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found to an provide guidelines for predicting when this complex fracturing occurs.« less

Cryogenic thermal diode heat pipes

NASA Technical Reports Server (NTRS)

Alario, J.

1979-01-01

The development of spiral artery cryogenic thermal diode heat pipes was continued. Ethane was the working fluid and stainless steel the heat pipe material in all cases. The major tasks included: (1) building a liquid blockage (blocking orifice) thermal diode suitable for the HEPP space flight experiment; (2) building a liquid trap thermal diode engineering model; (3) retesting the original liquid blockage engineering model, and (4) investigating the startup dynamics of artery cryogenic thermal diodes. An experimental investigation was also conducted into the wetting characteristics of ethane/stainless steel systems using a specially constructed chamber that permitted in situ observations.

Heat pipe thermal conditioning panel

NASA Technical Reports Server (NTRS)

Saaski, E. W.; Loose, J. D.; Mccoy, K. E.

1974-01-01

Thermal control of electronic hardware and experiments on future space vehicles is critical to proper functioning and long life. Thermal conditioning panels (cold plates) are a baseline control technique in current conceptual studies. Heat generating components mounted on the panels are typically cooled by fluid flowing through integral channels within the panel. However, replacing the pumped fluid coolant loop within the panel with heat pipes offers attractive advantages in weight, reliability, and installation. This report describes the development and fabrication of two large 0.76 x 0.76 m heat pipe thermal conditioning panels to verify performance and establish the design concept.

Flowpath evaluation and reconnaissance by remote field Eddy current testing (FERRET)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smoak, A.E.; Zollinger, W.T.

1993-12-31

This document describes the design and development of FERRET (Flowpath Evaluation and Reconnaisance by Remote-field Eddy current Testing). FERRET is a system for inspecting the steel pipes which carry cooling water to underground nuclear waste storage tanks. The FERRET system has been tested in a small scale cooling pipe mock-up, an improved full scale mock-up, and in flaw detection experiments. Early prototype designs of FERRET and the FERRET launcher (a device which inserts, moves, and retrieves probes from a piping system) as well as the field-ready design are discussed.

Patients with prior vertebral or hip fractures treated with teriparatide in the Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) observational study.

PubMed

Beall, D P; Feldman, R G; Gordon, M L; Gruber, B L; Lane, J M; Valenzuela, G; Yim, D; Alam, J; Krege, J H; Krohn, K

2016-03-01

In patients in the Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) observational study with and without a prior vertebral or hip fracture, the incidence of nonvertebral fractures was lower with >6 months of teriparatide treatment than during the first 6 months. Clinical evidence on the effect of teriparatide in patients with prior fracture is limited. In the DANCE observational study, the incidence of nonvertebral fragility fractures (NVFX) decreased significantly in patients receiving teriparatide for >6 months (6-24 months) versus >0 to ≤6 months (reference period). We performed a post hoc analysis to assess the effect of teriparatide 20 μg/day in patients who entered DANCE with prior vertebral or hip fractures. The incidence of patients experiencing a NVFX for four 6-month intervals during and after treatment was compared with the reference period. Overall, 4085 patients received ≥1 dose of teriparatide. Of 3720 with sufficient data for efficacy analysis, 692 had prior vertebral fracture, including 179 with previous kyphoplasty/vertebroplasty; 290 had prior hip fracture. These patients were older, and those with prior vertebral fractures had more comorbid conditions at baseline than those without prior vertebral fractures. The incidence of patients experiencing NVFX declined over time in all patient groups. The fracture incidence rate declined 49 and 46%, respectively, in patients with and without prior vertebral fracture and was 63 and 46% lower in patients with previous kyphoplasty/vertebroplasty and without prior vertebral fracture. NVFX declined 43 and 48% in patients with and without prior hip fracture. The reduced incidence over time was consistent in the subgroups (all interaction p values >0.05). Patients with prior fracture were more likely to experience serious adverse events. The incidence of NVFX decreased over time in patients receiving teriparatide in DANCE regardless of prior fracture status.

Discontinuities in effective permeability due to fracture percolation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyman, Jeffrey De'Haven; Karra, Satish; Carey, James William

Motivated by a triaxial coreflood experiment with a sample of Utica shale where an abrupt jump in permeability was observed, possibly due to the creation of a percolating fracture network through the sample, we perform numerical simulations based on the experiment to characterize how the effective permeability of otherwise low-permeability porous media depends on fracture formation, connectivity, and the contrast between the fracture and matrix permeabilities. While a change in effective permeability due to fracture formation is expected, the dependence of its magnitude upon the contrast between the matrix permeability and fracture permeability and the fracture network structure is poorlymore » characterized. We use two different high-fidelity fracture network models to characterize how effective permeability changes as percolation occurs. The first is a dynamic two-dimensional fracture propagation model designed to mimic the laboratory settings of the experiment. The second is a static three-dimensional discrete fracture network (DFN) model, whose fracture and network statistics are based on the fractured sample of Utica shale. Once the network connects the inflow and outflow boundaries, the effective permeability increases non-linearly with network density. In most networks considered, a jump in the effective permeability was observed when the embedded fracture network percolated. We characterize how the magnitude of the jump, should it occur, depends on the contrast between the fracture and matrix permeabilities. For small contrasts between the matrix and fracture permeabilities the change is insignificant. However, for larger contrasts, there is a substantial jump whose magnitude depends non-linearly on the difference between matrix and fracture permeabilities. A power-law relationship between the size of the jump and the difference between the matrix and fracture permeabilities is observed. In conclusion, the presented results underscore the importance of fracture network topology on the upscaled properties of the porous medium in which it is embedded.« less

Discontinuities in effective permeability due to fracture percolation

DOE PAGES

Hyman, Jeffrey De'Haven; Karra, Satish; Carey, James William; ...

2018-01-31

Motivated by a triaxial coreflood experiment with a sample of Utica shale where an abrupt jump in permeability was observed, possibly due to the creation of a percolating fracture network through the sample, we perform numerical simulations based on the experiment to characterize how the effective permeability of otherwise low-permeability porous media depends on fracture formation, connectivity, and the contrast between the fracture and matrix permeabilities. While a change in effective permeability due to fracture formation is expected, the dependence of its magnitude upon the contrast between the matrix permeability and fracture permeability and the fracture network structure is poorlymore » characterized. We use two different high-fidelity fracture network models to characterize how effective permeability changes as percolation occurs. The first is a dynamic two-dimensional fracture propagation model designed to mimic the laboratory settings of the experiment. The second is a static three-dimensional discrete fracture network (DFN) model, whose fracture and network statistics are based on the fractured sample of Utica shale. Once the network connects the inflow and outflow boundaries, the effective permeability increases non-linearly with network density. In most networks considered, a jump in the effective permeability was observed when the embedded fracture network percolated. We characterize how the magnitude of the jump, should it occur, depends on the contrast between the fracture and matrix permeabilities. For small contrasts between the matrix and fracture permeabilities the change is insignificant. However, for larger contrasts, there is a substantial jump whose magnitude depends non-linearly on the difference between matrix and fracture permeabilities. A power-law relationship between the size of the jump and the difference between the matrix and fracture permeabilities is observed. In conclusion, the presented results underscore the importance of fracture network topology on the upscaled properties of the porous medium in which it is embedded.« less

Introducing bio- and micro-technology into undergraduate thermal-fluids courses: investigating pipe pressure loss via atomic force microscopy.

PubMed

Müller, Marcus; Traum, Matthew J

2012-01-01

To introduce bio- and micro-technologies into general undergraduate thermal-fluids classes, a hands-on interdisciplinary in-class demonstration is described that juxtaposes classical pressure loss pipe flow experiments against a modern micro-characterization technique, AFM profilometry. Both approaches measure surface roughness and can segue into classroom discussions related to material selection and design of bio-medical devices to handle biological fluids such as blood. Appealing to the range of engineering students populating a general thermal-fluids course, a variety of pipe/hose/tube materials representing a spectrum of disciplines can be tested using both techniques. This in-class demonstration relies on technical content already available in standard thermal-fluids textbooks, provides experimental juxtaposition between classical and micro-technology-enabled approaches to the same experiment, and can be taught by personnel with no specialized micro- or bio-technology expertise.

Chemical and Thermal Analysis

NASA Technical Reports Server (NTRS)

Bulluck, J. W.; Rushing, R. A.

1995-01-01

During the past six months we have conducted significant research in several domains in order to clarify and understanding the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) for pipes. We organized numerous analytical studies with methods including Fourier Transform Infrared Spectroscopy, Dynamic Mechanical Analysis, Differential Scanning Calorimetry, and Stress Relaxation experiments. In addition we have reanalyzed previous thermogravimetric data concerning the rate of deplasticization of Coflon pipe. We investigated a number of aged samples of both Tefzel and Coflon that were forwarded from MERL. We conducted stress relaxation experiments of Coflon pipe at several temperatures and determined an activation energy. We also examined the dynamic mechanical response PVDF during deplasticization and during methanol plasticization. We performed numerous DSC analyses to research the changing crystalline morphology. We have noted significant changes in crystallinity upon aging for both PVDF and Tefzel. Little variation in elemental composition was noted for many of the aged Coflon and Tefzel samples tested.

Treatment of Pediatric Condylar Fractures: A 20-Year Experience.

PubMed

Ghasemzadeh, Ali; Mundinger, Gerhard S; Swanson, Edward W; Utria, Alan F; Dorafshar, Amir H

2015-12-01

The purpose of this study was to define patterns of injury and treatment for condylar and subcondylar fractures and evaluate short-term outcomes in the pediatric population. A retrospective chart review was performed on pediatric patients with mandibular condylar fractures who presented between 1990 and 2010. Computed tomographic imaging was reviewed for all patients to assess fracture characteristics. Mandibular fractures were codified using the Strasbourg Osteosynthesis Research Group and Lindahl classification methods. Sixty-four patients with 92 condylar fractures were identified. Of these patients, 29 had isolated condylar fracture and 35 had a condylar fracture associated with an additional mandibular arch fracture. The most common fracture patterns were diacapitular fracture in the Strasbourg Osteosynthesis Research Group system (n = 46) and vertical condylar head fracture in the Lindahl system (n = 14). Condylar fracture with additional mandibular arch fractures were treated with maxillomandibular fixation more often than patients with condylar fracture [n = 40 (74.1 percent) versus n = 14 (25.9 percent); p = 0.004]. No condylar fracture was treated in an open fashion. Forty-three patients returned for follow-up. The median follow-up period was 81 days (interquartile range, 35 to 294 days). Ten patients had complications (23.3 percent). The most common complication was malocclusion (n = 5). Nine of 10 patients with complications had condylar fracture with an additional mandibular arch fracture. Closed treatment of condylar fractures yields satisfactory results in pediatric patients. Pediatric patients with condylar fractures combined with additional arch fractures experience a higher rate of unfavorable outcomes.

Directionality and Orientation Effects on the Resistance to Propagating Shear Failure

NASA Astrophysics Data System (ADS)

Leis, B. N.; Barbaro, F. J.; Gray, J. M.

Hydrocarbon pipelines transporting compressible products like methane or high-vapor-pressure (HVP) liquids under supercritical conditions can be susceptible to long-propagating failures. As the unplanned release of such hydrocarbons can lead to significant pollution and/or the horrific potential of explosion and/or a very large fire, design criteria to preclude such failures were essential to environmental and public safety. Thus, technology was developed to establish the minimum arrest requirements to avoid such failures shortly after this design concern was evident. Soon after this technology emerged in the early 1970sit became evident that its predictions were increasinglynon-conservative as the toughness of line-pipe steel increased. A second potentially critical factor for what was a one-dimensional technology was that changes in steel processing led to directional dependence in both the flow and fracture properties. While recognized, this dependence was tacitly ignored in quantifying arrest, as were early observations that indicated propagating shear failure was controlled by plastic collapse rather than by fracture processes.

The International Heat Pipe Experiment. [international cooperation zero g experiment

NASA Technical Reports Server (NTRS)

Mcintosh, R.; Ollendorf, S.; Harwell, W.

1976-01-01

The aims of the experiment are outlined. Flight experiments included in this program were provided by NASA, Goddard Space Flight Center, ESA (European Space Agency), the German Ministry of Technology, Hughes Aircraft Company and NASA, Ames Research Center.

Heat pipe dynamic behavior

NASA Technical Reports Server (NTRS)

Issacci, F.; Roche, G. L.; Klein, D. B.; Catton, I.

1988-01-01

The vapor flow in a heat pipe was mathematically modeled and the equations governing the transient behavior of the core were solved numerically. The modeled vapor flow is transient, axisymmetric (or two-dimensional) compressible viscous flow in a closed chamber. The two methods of solution are described. The more promising method failed (a mixed Galerkin finite difference method) whereas a more common finite difference method was successful. Preliminary results are presented showing that multi-dimensional flows need to be treated. A model of the liquid phase of a high temperature heat pipe was developed. The model is intended to be coupled to a vapor phase model for the complete solution of the heat pipe problem. The mathematical equations are formulated consistent with physical processes while allowing a computationally efficient solution. The model simulates time dependent characteristics of concern to the liquid phase including input phase change, output heat fluxes, liquid temperatures, container temperatures, liquid velocities, and liquid pressure. Preliminary results were obtained for two heat pipe startup cases. The heat pipe studied used lithium as the working fluid and an annular wick configuration. Recommendations for implementation based on the results obtained are presented. Experimental studies were initiated using a rectangular heat pipe. Both twin beam laser holography and laser Doppler anemometry were investigated. Preliminary experiments were completed and results are reported.

In-line inspection of unpiggable buried live gas pipes using circumferential EMAT guided waves

NASA Astrophysics Data System (ADS)

Ren, Baiyang; Xin, Junjun

2018-04-01

Unpiggable buried gas pipes need to be inspected to ensure their structural integrity and safe operation. The CIRRIS XITM robot, developed and operated by ULC Robotics, conducts in-line nondestructive inspection of live gas pipes. With the no-blow launching system, the inspection operation has reduced disruption to the public and by eliminating the need to dig trenches, has minimized the site footprint. This provides a highly time and cost effective solution for gas pipe maintenance. However, the current sensor on the robot performs a point-by-point measurement of the pipe wall thickness which cannot cover the whole volume of the pipe in a reasonable timeframe. The study of ultrasonic guided wave technique is discussed to improve the volume coverage as well as the scanning speed. Circumferential guided wave is employed to perform axial scanning. Mode selection is discussed in terms of sensitivity to different defects and defect characterization capability. To assist with the mode selection, finite element analysis is performed to evaluate the wave-defect interaction and to identify potential defect features. Pulse-echo and through-transmission mode are evaluated and compared for their pros and cons in axial scanning. Experiments are also conducted to verify the mode selection and detect and characterize artificial defects introduced into pipe samples.

Material property relationships for pipeline steels and the potential for application of NDE

NASA Astrophysics Data System (ADS)

Smart, Lucinda; Bond, Leonard J.

2016-02-01

The oil and gas industry in the USA has an extensive infrastructure of pipelines, 70% of which were installed prior to 1980, and almost half were installed during the 1950s and 1960s. Ideally the mechanical properties (i.e. yield strength, tensile strength, transition temperature, and fracture toughness) of a steel pipe must be known in order to respond to detected defects in an appropriate manner. Neither current in-ditch methods nor the ILI inspection data have yet determined and map the desired mechanical properties with adequate confidence. In the quest to obtain the mechanical properties of a steel pipe using a nondestructive method, it is important to understand that there are many inter-related variables. This paper reports a literature review and an analysis of a sample set of data. There is promise for correlating the results of NDE measurement modalities to the information required to develop relationships between those measurements and the mechanical measurements desired for pipelines to ensure proper response to defects which are of significant threat.

Dam break analysis and flood inundation map of Krisak dam for emergency action plan

NASA Astrophysics Data System (ADS)

Juliastuti, Setyandito, Oki

2017-11-01

The Indonesian Regulation which refers to the ICOLD Regulation (International Committee on Large Dam required have the Emergency Action Plan (EAP) guidelines because of the dams have potential failure. In EAP guidelines there is a management of evacuation where the determination of the inundation map based on flood modeling. The purpose of the EAP is to minimize the risk of loss of life and property in downstream which caused by dam failure. This paper will describe about develop flood modeling and inundation map in Krisak dam using numerical methods through dam break analysis (DBA) using hydraulic model Zhong Xing HY-21. The approaches of dam failure simulation are overtopping and piping. Overtopping simulation based on quadrangular, triangular and trapezium fracture. Piping simulation based on cracks of orifice. Using results of DBA, hazard classification of Krisak dam is very high. The nearest village affected dam failure is Singodutan village (distance is 1.45 kilometer from dam) with inundation depth is 1.85 meter. This result can be used by stakeholders such as emergency responders and the community at risk in formulating evacuation procedure.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kot, C.A.; Srinivasan, M.G.; Hsieh, B.J.

As part of the Phase II testing at the HDR Test Facility in Kahl/Main, FRG, two series of high-level seismic/vibrational experiments were performed. In the first of these (SHAG) a coast-down shaker, mounted on the reactor operating floor and capable of generating 1000 tonnes of force, was used to investigate full-scale structural response, soil-structure interaction (SSI), and piping/equipment response at load levels equivalent to those of a design basis earthquake. The HDR soil/structure system was tested to incipient failure exhibiting highly nonlinear response. In the load transmission from structure to piping/equipment significant response amplifications and shifts to higher frequencies occurred.more » The performance of various pipe support configurations was evaluated. This latter effort was continued in the second series of tests (SHAM), in which an in-plant piping system was investigated at simulated seismic loads (generated by two servo-hydraulic actuators each capable of generating 40 tonnes of force), that exceeded design levels manifold and resulted in considerable pipe plastification and failure of some supports (snubbers). The evaluation of six different support configurations demonstrated that proper system design (for a given spectrum) rather than number of supports or system stiffness is essential to limiting pipe stresses. Pipe strains at loads exceeding the design level eightfold were still tolerable, indicating that pipe failure even under extreme seismic loads is unlikely inspite of multiple support failures. Conservatively, an excess capacity (margin) of at least four was estimated for the piping system, and the pipe damping was found to be 4%. Comparisons of linear and nonlinear computational results with measurements showed that analytical predictions have wide scatter and do not necessarily yield conservative responses, underpredicting, in particular, peak support forces.« less

Non-planar vibrations of slightly curved pipes conveying fluid in simple and combination parametric resonances

NASA Astrophysics Data System (ADS)

Czerwiński, Andrzej; Łuczko, Jan

2018-01-01

The paper summarises the experimental investigations and numerical simulations of non-planar parametric vibrations of a statically deformed pipe. Underpinning the theoretical analysis is a 3D dynamic model of curved pipe. The pipe motion is governed by four non-linear partial differential equations with periodically varying coefficients. The Galerkin method was applied, the shape function being that governing the beam's natural vibrations. Experiments were conducted in the range of simple and combination parametric resonances, evidencing the possibility of in-plane and out-of-plane vibrations as well as fully non-planar vibrations in the combination resonance range. It is demonstrated that sub-harmonic and quasi-periodic vibrations are likely to be excited. The method suggested allows the spatial modes to be determined basing on results registered at selected points in the pipe. Results are summarised in the form of time histories, phase trajectory plots and spectral diagrams. Dedicated video materials give us a better insight into the investigated phenomena.

The formation of floor-fractured craters in Xanthe Terra

NASA Astrophysics Data System (ADS)

Sato, Hiroyuki; Kurita, Kei; Baratoux, David

2010-05-01

Floor-fractured craters (FFC) are a peculiar form of degradation of impact craters defined by the presence of crevice networks and mesas affecting crater floors. They are preferentially distributed near chaotic terrains and outflow channels. The scope of this paper is to present a detailed systematic analysis of FFC at Xanthe Terra. FFC morphologies in this region are classified into five types making a picture of different stages of the same degradation process. FFC are geographically intermixed with un-fractured normal craters (non-FFC). Young craters are less prone to show this type of degradation, as suggested by fresh ejecta layer with preserved crater floor. Size distributions of FFC and non-FFC indicate that larger craters are preferentially fractured. Careful examinations of the crater floor elevations reveal that the crevices often extend deeper than the original crater cavity. Furthermore, an onset depth for the formation of FFC is evidenced from the difference of spatial distributions between FFC and non-FFC. Roof-collapsed depressions observed in the same region have been also documented and their characteristics suggest the removal of subsurface material at depth from about 1200 to 4000 m. These observations taken together suggest a subsurface zone of volume deficit at depth from 1 to 2 km down to several kilometers responsible for FFC formation. Then a scenario of FFC formations is presented in the context of groundwater discharge events at the late Hesperian. This scenario involves two key processes, Earth fissuring and piping erosion, known to occur with rapid groundwater migrations on Earth.

FY 2017-Progress Report on the Design and Construction of the Sodium Loop SMT-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Natesan, K.; Momozaki, Y.

This report provides an update on the design of a forced-convection sodium loop to be used for the evaluation of sodium compatibility of advanced Alloy 709 with emphasis on long term exposures of tensile, creep, fatigue, creep fatigue, and fracture toughness ASTM-size specimens in support of ASME Code qualification and NRC licensing. The report is a deliverable (Level 4) in FY17 (M4AT-17AN1602094), under the Work Package AT-17AN160209, “Sodium Compatibility” performed by Argonne National Laboratory (ANL), as part of the Advanced Materials Program for the Advanced Reactor Technology. This work package enables the development of advanced structural materials by providing corrosion,more » microstructure, and mechanical property data from the standpoint of sodium compatibility of advanced structural alloys. The first sodium loop (SMT-1) with a single tank was constructed in 2011 at ANL and has been in operation for exposure of subsize sheet specimens of advanced alloys at a single temperature. The second sodium loop with dual tanks (SMT-2) was constructed in 2013 and has been in operation for the exposure of subsize sheet specimens of advanced alloys at two different temperatures. The current loop (SMT-3) has been designed to incorporate sufficient chamber capacity to expose a large number of ASTM-size specimens to evaluate the sodium effects on tensile, creep, fatigue, creep-fatigue, and fracture toughness properties, in support of ASME Code Qualification and USNRC Licensing. The design of individual components for the third sodium loop SMT-3 is almost complete. The design also has been sent to an outside vendor for piping analysis to be in compliance with ASME Code. A purchase order has been placed with an outside vendor for the fabrication of major components such as the specimen exposure tanks. However, we have contracted with another vendor to establish the piping design in compliance with ASME design codes. The piping design was completed in FY2017 and the information is being transmitted to the tank fabricator. The SMT-3 loop will be located in Building 206 adjacent to the currently operating SMT-2 loop. In addition, we have demolished the aged power supply system in Building 206 and installed a new transformer, wiring, and power panels for the new loop. Procurement of some of the long lead items such as valves, EM pumps, EM flowmeters, etc. is in progress and will continue in FY 2018. The construction of components such as cold trap, economizers, piping arrangement etc. will be performed in the central shops at ANL. About 150 liters of sodium for the loop will be procured in early FY2018. The loop system is designed to circulate sodium through the sample tanks and the associated loop without an operator for an extended period of time. With the three sodium loops (with single-tank, dual-tank and four–tanks), materials can be tested at different sodium temperatures, and large tensile, creep, fatigue, creep-fatigue, and fracture toughness specimens can be exposed to sodium for extended periods of time and generate data on mechanical properties in support of ASME Code Qualification and USNRC Licensing of advanced Alloy 709 for use as a structural material in SFRs.« less

ANALYSIS OF MATERIALS IN AN EXPERIMENTAL TESTING PIPE SYSTEM FOR AN INHIBITOR OF MUSSEL KILL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel P. Molloy

2003-06-04

A comprehensive series of 16 laboratory experiments demonstrated that the presence of vinyl tubing within a recirculating pipe system was responsible for lowering zebra mussel kill following treatment with the bacterium Pseudomonas fluorescens. All vinyl tubing was replaced in all testing units with silicone tubing, and high mussel kill (>95%) was then obtained.

A bubble detection system for propellant filling pipeline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wen, Wen; Zong, Guanghua; Bi, Shusheng

2014-06-15

This paper proposes a bubble detection system based on the ultrasound transmission method, mainly for probing high-speed bubbles in the satellite propellant filling pipeline. First, three common ultrasonic detection methods are compared and the ultrasound transmission method is used in this paper. Then, the ultrasound beam in a vertical pipe is investigated, suggesting that the width of the beam used for detection is usually smaller than the internal diameter of the pipe, which means that when bubbles move close to the pipe wall, they may escape from being detected. A special device is designed to solve this problem. It canmore » generate the spiral flow to force all the bubbles to ascend along the central line of the pipe. In the end, experiments are implemented to evaluate the performance of this system. Bubbles of five different sizes are generated and detected. Experiment results show that the sizes and quantity of bubbles can be estimated by this system. Also, the bubbles of different radii can be distinguished from each other. The numerical relationship between the ultrasound attenuation and the bubble radius is acquired and it can be utilized for estimating the unknown bubble size and measuring the total bubble volume.« less

Theoretical and Experimental Aspects of Acoustic Modelling of Engine Exhaust Systems with Applications to a Vacuum Pump

NASA Astrophysics Data System (ADS)

Sridhara, Basavapatna Sitaramaiah

In an internal combustion engine, the engine is the noise source and the exhaust pipe is the main transmitter of noise. Mufflers are often used to reduce engine noise level in the exhaust pipe. To optimize a muffler design, a series of experiments could be conducted using various mufflers installed in the exhaust pipe. For each configuration, the radiated sound pressure could be measured. However, this is not a very efficient method. A second approach would be to develop a scheme involving only a few measurements which can predict the radiated sound pressure at a specified distance from the open end of the exhaust pipe. In this work, the engine exhaust system was modelled as a lumped source-muffler-termination system. An expression for the predicted sound pressure level was derived in terms of the source and termination impedances, and the muffler geometry. The pressure source and monopole radiation models were used for the source and the open end of the exhaust pipe. The four pole parameters were used to relate the acoustic properties at two different cross sections of the muffler and the pipe. The developed formulation was verified through a series of experiments. Two loudspeakers and a reciprocating type vacuum pump were used as sound sources during the tests. The source impedance was measured using the direct, two-load and four-load methods. A simple expansion chamber and a side-branch resonator were used as mufflers. Sound pressure level measurements for the prediction scheme were made for several source-muffler and source-straight pipe combinations. The predicted and measured sound pressure levels were compared for all cases considered. In all cases, correlation of the experimental results and those predicted by the developed expressions was good. Predicted and measured values of the insertion loss of the mufflers were compared. The agreement between the two was good. Also, an error analysis of the four-load method was done.

Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Douglas, Donya

2008-01-01

This paper presents the development of the Thermal Loop experiment under NASA's New Millennium Program Space Technology 8 (ST8) Project. The Thermal Loop experiment was originally planned for validating in space an advanced heat transport system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers. Details of the thermal loop concept, technical advances and benefits, Level 1 requirements and the technology validation approach are described. An MLHP breadboard has been built and tested in the laboratory and thermal vacuum environments, and has demonstrated excellent performance that met or exceeded the design requirements. The MLHP retains all features of state-of-the-art loop heat pipes and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. In addition, an analytical model has been developed to simulate the steady state and transient operation of the MHLP, and the model predictions agreed very well with experimental results. A protoflight MLHP has been built and is being tested in a thermal vacuum chamber to validate its performance and technical readiness for a flight experiment.

Modelling Laccoliths: Fluid-Driven Fracturing in the Lab

NASA Astrophysics Data System (ADS)

Ball, T. V.; Neufeld, J. A.

2017-12-01

Current modelling of the formation of laccoliths neglects the necessity to fracture rock layers for propagation to occur [1]. In magmatic intrusions at depth the idea of fracture toughness is used to characterise fracturing, however an analogue for near surface intrusions has yet to be explored [2]. We propose an analytical model for laccolith emplacement that accounts for the energy required to fracture at the tip of an intrusion. For realistic physical parameters we find that a lag region exists between the fluid magma front and the crack tip where large negative pressures in the tip cause volatiles to exsolve from the magma. Crucially, the dynamics of this tip region controls the spreading due to the competition between viscous forces and fracture energy. We conduct a series of complementary experiments to investigate fluid-driven fracturing of adhered layers and confirm the existence of two regimes: viscosity dominant spreading, controlled by the pressure in the lag region, and fracture energy dominant spreading, controlled by the energy required to fracture layers. Our experiments provide the first observations, and evolution, of a vapour tip. These experiments and our simplified model provide insight into the key physical processes in near surface magmatic intrusions with applications to fluid-driven fracturing more generally. Michaut J. Geophys. Res. 116(B5), B05205. Bunger & Cruden J. Geophys. Res. 116(B2), B02203.

Seismic and structural characterization of the fluid bypass system using 3D and partial stack seismic from passive margin: inside the plumbing system.

NASA Astrophysics Data System (ADS)

Iacopini, David; Maestrelli, Daniele; Jihad, Ali; Bond, Clare; Bonini, Marco

2017-04-01

In recent years enormous attention has been paid to the understanding of the process and mechanism controlling the gas seepage and more generally the fluid expulsion affecting the earth system from onshore to offshore environment. This is because of their demonstrated impact to our environment, climate change and during subsea drilling operation. Several example from active and paleo system has been so far characterized and proposed using subsurface exploration, geophysical and geochemical monitoring technology approaches with the aims to explore what trigger and drive the overpressure necessary maintain the fluid/gas/material expulsion and what are the structure that act as a gateway for gaseous fluid and unconsolidated rock. In this contribution we explore a series of fluid escape structure (ranging from seepage pipes to large blowout pipes structure of km length) using 3D and partial stack seismic data from two distinctive passive margin from the north sea (Loyal field, West Shetland) and the Equatorial Brazil (Ceara' Basin). We will focuses on the characterization of the plumbing system internal architecture and, for selected example, exploring the AVO response (using partial stack) of the internal fluid/unconsolidated rock. The detailed seismic mapping and seismic attributes analysis of the conduit system helped us to recover some detail from the signal response of the chimney internal structures. We observed: (1) small to medium seeps and pipes following structural or sedimentary discontinuities (2) large pipes (probably incipient mud volcanoes) and blowup structures propagating upward irrespective of pre-existing fault by hydraulic fracturing and assisted by the buoyancy of a fluidised and mobilised mud-hydrocarbon mixture. The reflector termination observed inside the main conduits, the distribution of stacked bright reflectors and the AVO analysis suggests an evolution of mechanisms (involving mixture of gas, fluid and probably mud) during pipe birth and development, cycling through classical fluid escape pipes evoking non-Darcy flow to Darcy flow exploiting surrounding permeable bodies (during low fluid recharge period). Limit and uncertainty of the seismic data imaging the internal structure are still controlled by illumination factor, the lateral and vertical resolution (Fresnel. Tuning thickness) and scattering/noise effect of seismic wave when they interact with the plumbing system.

Experimental investigation on the effect of nanofluid on the thermal performance of symmetric sintered U shaped heat pipe

NASA Astrophysics Data System (ADS)

Nazarimanesh, Meysam; Yousefi, Tooraj; Ashjaee, Mehdi

2016-07-01

In this study, the impact of Entrance Power and Silver nanofluid concentration (with base fluid ethanol and DI-water) on heat pipe thermal performance are considered. In order to reach the aim a U-shaped sintered heat pipe is utilized which causes occupied space to decline. The length of the heat pipe is 135 mm in each branch. On account of recognition the effect of working fluid on heat pipe thermal performance, thermal resistance and overall heat transfer coefficient in base working fluid and nano-colloidal silver are measured in the shape of thermosyphon. The working fluid is with volume percentages of 70 ethanol and 30 distilled water. The average size pertaining to the nanoparticle applied is 40 nm. In addition, the influences of nanofluid concentrations are measured by comparing three concentrations 0.001, 0.005, 0.1 vol%. The range of entrance power is from 10 to 40 W and the temperature of coolant has been changed from 20 to 40 °C. The results of the experiment indicate that by increasing entrance power, the temperatures of the condenser, evaporator and working temperature experience a rise. Furthermore, this causes a decrease of thermal resistance and an increase of overall heat transfer coefficient. A comparison of three concentrations reveals that in concentration of 50 ppm, thermal resistance compared to the base fluid has decreased to 42.26 % and overall heat transfer coefficient has gone up to 1883 (W/m2·°K) . Also, due to unexpected changes in concentration of 1000 ppm, the existence of an optimized concentration for the silver nanofluid in this heat pipe with this geometry has been clear.

Comparing slow and fast rupture in laboratory experiments

NASA Astrophysics Data System (ADS)

Aben, F. M.; Brantut, N.; David, E.; Mitchell, T. M.

2017-12-01

During the brittle failure of rock, elastically stored energy is converted into a localized fracture plane and surrounding fracture damage, seismic radiation, and thermal energy. However, the partitioning of energy might vary with the rate of elastic energy release during failure. Here, we present the results of controlled (slow) and dynamic (fast) rupture experiments on dry Lanhélin granite and Westerly granite samples, performed under triaxial stress conditions at confining pressures of 50 and 100 MPa. During the tests, we measured sample shortening, axial load and local strains (with 2 pairs of strain gauges glued directly onto the sample). In addition, acoustic emissions (AEs) and changes in seismic velocities were monitored. The AE rate was used as an indicator to manually control the axial load on the sample to stabilize rupture in the quasi-static failure experiments. For the dynamic rupture experiments a constant strain rate of 10-5 s-1 was applied until sample failure. A third experiment, labeled semi-controlled rupture, involved controlled rupture up to a point where the rupture became unstable and the remaining elastic energy was released dynamically. All experiments were concluded after a macroscopic fracture had developed across the whole sample and frictional sliding commenced. Post-mortem samples were epoxied, cut and polished to reveal the macroscopic fracture and the surrounding damage zone. The samples failed with average rupture velocities varying from 5x10-6 m/s up to >> 0.1 m/s. The analyses of AE locations on the slow ruptures reveal that within Westerly granite samples - with a smaller grain size - fracture planes are disbanded in favor of other planes when a geometrical irregularity is encountered. For the coarser grained Lanhélin granite a single fracture plane is always formed, although irregularities are recognized as well. The semi-controlled experiments show that for both rock types the rupture can become unstable in response to these irregularities. In Westerly granite, slow rupture experiments tend to produce complex fracture patterns while during the dynamic rupture experiments secondary rupture planes are not formed. These findings show that grain or flaw size, flaw distribution, and rupture speed strongly influence fracture localization and propagation.

Seismic detection of a hydraulic fracture from shear-wave VSP data at Lost Hills Field, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meadows, M.A.; Winterstein, D.F.

1994-01-01

The authors describe the results of a geophysical experiment in which shear waves (S-waves) were used to detect the presence of a hydraulic fracture in a diatomite reservoir at the Lost Hills Field. They show evidence that transient S-waves recorded in a monitor well represent diffracted energy that disappears as the fracture closes. They also show how, using simple models, one can establish limits on fracture lengths and heights by accurately modeling the scattered wavefield. These limits are dependent upon both the recording geometry and the wavelength of the S-waves incident on the fracture. The principles of S-wave recording andmore » processing described here can provide important information about the geometry of induced fractures, which are becoming increasingly important for enhanced recovery. The paper presents background information about the Lost Hills Field and provide other details relevant for mapping induced fractures. The remainder of the paper treats the data processing and modeling of the experiment itself and discusses the implications for future experiments of this type.« less

Subcritical fracture propagation in rocks: An examination using the methods of fracture mechanics and non-destructive testing. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Swanson, P. L.

1984-01-01

An experimental investigation of tensile rock fracture is presented with an emphasis on characterizing time dependent crack growth using the methods of fracture mechanics. Subcritical fracture experiments were performed in moist air on glass and five different rock types at crack velocities using the double torsion technique. The experimental results suggest that subcritical fracture resistance in polycrystals is dominated by microstructural effects. Evidence for gross violations of the assumptions of linear elastic fracture mechanics and double torsion theory was found in the tests on rocks. In an effort to obtain a better understanding of the physical breakdown processes associated with rock fracture, a series of nondestructive evaluation tests were performed during subcritical fracture experiments on glass and granite. Comparison of the observed process zone shape with that expected on the basis of a critical normal principal tensile stress criterion shows that the zone is much more elongated in the crack propagation direction than predicted by the continuum based microcracking model alone.

Treatment of Pediatric Condylar Fractures: A 20-Year Experience

PubMed Central

Ghasemzadeh, Ali; Mundinger, Gerhard S.; Swanson, Edward W.; Utria, Alan F.; Dorafshar, Amir H.

2016-01-01

Background The purpose of this study was to define patterns of injury and treatment for condylar and subcondylar fractures and evaluate short-term outcomes in the pediatric population. Methods A retrospective chart review was performed on pediatric patients with mandibular condylar fractures who presented between 1990 and 2010. Computed tomographic imaging was reviewed for all patients to assess fracture characteristics. Mandibular fractures were codified using the Strasbourg Osteosynthesis Research Group and Lindahl classification methods. Results Sixty-four patients with 92 condylar fractures were identified. Of these patients, 29 had isolated condylar fracture and 35 had a condylar fracture associated with an additional mandibular arch fracture. The most common fracture patterns were diacapitular fracture in the Strasbourg Osteosynthesis Research Group system (n = 46) and vertical condylar head fracture in the Lindahl system (n = 14). Condylar fracture with additional mandibular arch fractures were treated with maxillomandibular fixation more often than patients with condylar fracture [n = 40 (74.1 percent) versus n = 14 (25.9 percent); p = 0.004]. No condylar fracture was treated in an open fashion. Forty-three patients returned for follow-up. The median follow-up period was 81 days (interquartile range, 35 to 294 days). Ten patients had complications (23.3 percent). The most common complication was malocclusion (n = 5). Nine of 10 patients with complications had condylar fracture with an additional mandibular arch fracture. Conclusions Closed treatment of condylar fractures yields satisfactory results in pediatric patients. Pediatric patients with condylar fractures combined with additional arch fractures experience a higher rate of unfavorable outcomes. PMID:26595021

Development of electrical feedback controlled heat pipes and the advanced thermal control flight experiment

NASA Technical Reports Server (NTRS)

Bienert, W. B.

1974-01-01

The development and characteristics of electrical feedback controlled heat pipes (FCHP) are discussed. An analytical model was produced to describe the performance of the FCHP under steady state and transient conditions. An advanced thermal control flight experiment was designed to demonstrate the performance of the thermal control component in a space environment. The thermal control equipment was evaluated on the ATS-F satellite to provide performance data for the components and to act as a thermal control system which can be used to provide temperature stability of spacecraft components in future applications.

The "Long Pipe" in CICLoPE: A Design for Detailed Turbulence Measurements

NASA Astrophysics Data System (ADS)

Talamelli, A.; Bellani, G.; Rossetti, A.

A new facility to study high Reynolds number wall bounded turbulent flow has been designed. It will be installed in the laboratory of Center for International Collaboration on Long Pipe Experiments "CICLoPE" in Predappio (Italy). The facility consists of a large pipe, allowing to reach high Reynolds numbers, where all turbulent scales can be resolved with standard measurement techniques. The pipe operates with air at ambient conditions with a maximum speed of 60 m/s in order to avoid any compressibility effect. In order to maintain stable conditions over long period of time the pipe is part of a close loop circuit. The pipe will be located in a tunnel 60 m underground, thus ensuring very low level of external perturbations. The layout resembles an ordinary wind tunnel where the main difference is the long test section, which produces most of the friction losses. This requires the use of a multiple stage axial fan driven by two independent motors. Even though many of the various aerodynamic components are similar to those ordinary used in wind tunnel (corners, diffusers, turbulence manipulators, contraction, etc.) they have been designed aiming at obtaining a very good quality of the flow and minimizing the overall pressure losses.

Leaching of lead from new unplasticized polyvinyl chloride (uPVC) pipes into drinking water.

PubMed

Zhang, Yuanyuan; Lin, Yi-Pin

2015-06-01

Unplasticized polyvinyl chloride (uPVC) pipes have been used in the premise plumbing system due to their high strength, long-term durability, and low cost. uPVC pipes, however, may contain lead due to the use of lead compounds as the stabilizer during the manufacturing process. The release of lead from three locally purchased uPVC pipes was investigated in this study. The effects of various water quality parameters including pH value, temperature, and type of disinfectant on the rate of lead release were examined. The elemental mapping obtained using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) confirmed the presence of lead on the inner surfaces of the uPVC pipes and their surface lead weight percentages were determined. The leachable lead concentration for each pipe was determined using high strength acidic EDTA solutions (pH 4, EDTA = 100 mg/L). Lead leaching experiments using tap water and reconstituted tape water under static conditions showed that the rate of lead release increased with the decreasing pH value and increasing temperature. In the presence of monochloramine, lead release was faster than that in the presence of free chlorine.

Tilt angle dependence of backscattering enhancements from organ pipe modes of open water-filled cylinders: Measurements and models

NASA Astrophysics Data System (ADS)

Osterhoudt, Curtis F.; Marston, Philip L.

2003-04-01

A simple target for simulating narrow low-frequency resonances of cylinders is an open metal pipe completely filled with water. We have previously described how the high-Q organ-pipe modes having a pressure node near each end are easily observed in backscattering experiments with small cylinders [C. F. Osterhoudt and P. L. Marston, J. Acoust. Soc. Am. 110, 2773 (2001)]. The resonance occurs because of the strong reflection of internal acoustic waves from the open ends of the pipe [H. Levine and J. Schwinger, Phys. Rev. 73, 383-406 (1948)]. In the present research, the dependence of the backscattering amplitude on the orientation of the cylinder is measured and modeled. The tilt angle dependence is affected by the symmetry of the organ pipe mode. An approximation was also developed for the backscattering amplitude at high Q resonances based on energy conservation, reciprocity, and the optical theorem. While this analysis applies to cylinders suspended in water away from boundaries, the organ-pipe modes studied may be useful for investigating scattering processes for buried or partially buried cylinders. [Research supported in part by ONR.

Experimental insights into geochemical changes in hydraulically fractured Marcellus Shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcon, Virginia; Joseph, Craig; Carter, Kimberly E.

Hydraulic fracturing applied to organic-rich shales has significantly increased the recoverable volume of methane available for U.S. energy consumption. Fluid-shale reactions in the reservoir may affect long-term reservoir productivity and waste management needs through changes to fracture mineral composition and produced fluid chemical composition. We performed laboratory experiments with Marcellus Shale and lab-generated hydraulic fracturing fluid at elevated pressures and temperatures to evaluate mineral reactions and the release of trace elements into solution. Results from the experiment containing fracturing chemicals show evidence for clay and carbonate dissolution, secondary clay and anhydrite precipitation, and early-stage (24-48 h) fluid enrichment of certainmore » elements followed by depletion in later stages (i.e. Al, Cd, Co, Cr, Cu, Ni, Sc, Zn). Other elements such as As, Fe, Mn, Sr, and Y increased in concentration and remained elevated throughout the duration of the experiment with fracturing fluid. Geochemical modeling of experimental fluid data indicates primary clay dissolution, and secondary formation of smectites and barite, after reaction with fracturing fluid. Changes in aqueous organic composition were observed, indicating organic additives may be chemically transformed or sequestered by the formation after hydraulic fracturing. The NaCl concentrations in our fluids are similar to measured concentrations in Marcellus Shale produced waters, showing that these experiments are representative of reservoir fluid chemistries and can provide insight on geochemical reactions that occur in the field. These results can be applied towards evaluating the evolution of hydraulically-fractured reservoirs, and towards understanding geochemical processes that control the composition of produced water from unconventional shales.« less

Experimental insights into geochemical changes in hydraulically fractured Marcellus Shale

DOE PAGES

Marcon, Virginia; Joseph, Craig; Carter, Kimberly E.; ...

2016-11-09

Hydraulic fracturing applied to organic-rich shales has significantly increased the recoverable volume of methane available for U.S. energy consumption. Fluid-shale reactions in the reservoir may affect long-term reservoir productivity and waste management needs through changes to fracture mineral composition and produced fluid chemical composition. We performed laboratory experiments with Marcellus Shale and lab-generated hydraulic fracturing fluid at elevated pressures and temperatures to evaluate mineral reactions and the release of trace elements into solution. Results from the experiment containing fracturing chemicals show evidence for clay and carbonate dissolution, secondary clay and anhydrite precipitation, and early-stage (24-48 h) fluid enrichment of certainmore » elements followed by depletion in later stages (i.e. Al, Cd, Co, Cr, Cu, Ni, Sc, Zn). Other elements such as As, Fe, Mn, Sr, and Y increased in concentration and remained elevated throughout the duration of the experiment with fracturing fluid. Geochemical modeling of experimental fluid data indicates primary clay dissolution, and secondary formation of smectites and barite, after reaction with fracturing fluid. Changes in aqueous organic composition were observed, indicating organic additives may be chemically transformed or sequestered by the formation after hydraulic fracturing. The NaCl concentrations in our fluids are similar to measured concentrations in Marcellus Shale produced waters, showing that these experiments are representative of reservoir fluid chemistries and can provide insight on geochemical reactions that occur in the field. These results can be applied towards evaluating the evolution of hydraulically-fractured reservoirs, and towards understanding geochemical processes that control the composition of produced water from unconventional shales.« less

Seismic stops for nuclear power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cloud, R.L.; Leung, J.S.M.; Anderson, P.H.

1989-10-01

In the regulated world of nuclear power, the need to have analytical proof of performance in hypothetical design-basis events such as earth quakes has placed a premium on design configurations that are mathematically tractable and easily analyzed. This is particularly true for the piping design. Depending on how the piping analyses are organized and on how old the plant is, there may be from 200 to 1000 separate piping runs to be designed, analyzed, and qualified. In this situation, the development of snubbers seemed like the answer to a piping engineer's prayer. At any place where seismic support was requiredmore » but thermal motion had to be accommodated, a snubber could be specified. But, as experience has now shown, the program was solved only on paper. This article presents an alternative to conventional snubbers. These new devices, termed Seismic Stops are designed to replace snubbers directly and look like snubbers on the outside. But their design is based on a completely different principle. The original concept has adapted from early seismic-resistant pipe support designs used on fossil power plants in California. The fundamental idea is to provide a space envelope in which the pipe can expand freely between the hot and cold positions, but cannot move outside the envelope. Seismic Stops are designed to transmit any possible impact load, as would occur in an earthquake, away from the pipe itself to the Seismic Stop. The Seismic Stop pipe support is shown.« less

Experimental Investigation of Thermal Performance of Miniature Heat Pipe Using SiO2-Water Nanofluids.

PubMed

Niu, Yan-Fang; Zhao, Wei-Lin; Gong, Yu-Ying

2015-04-01

The four miniature heat pipes filled with DI water and SiO2-water nanofluids containing different volume concentrations (0.2%, 0.6% and 1.0%) are experimentally measured on the condition of air and water cooling. The wall temperature and the thermal resistance are investigated for three inclination angles. At the same of inlet heat water temperature in the heat system, it is observed that the total wall temperatures on the evaporator section are almost retaining constant by air cooling and the wall temperatures at the front end of the evaporator section are slightly reduced by water cooling. However, the wall temperatures at the condenser section using SiO2-water nanofluids are all higher than that for DI water on the two cooling conditions. As compared with the heat pipe using DI water, the decreasing of the thermal resistance in heat pipe using nanofluids is about 43.10%-74.46% by air cooling and 51.43%-72.22% by water cooling. These indicate that the utilization of SiO2-water nanofluids as working fluids enhances the performance of the miniature heat pipe. When the four miniature heat pipes are cut to examine at the end of the experiment, a thin coating on the surface of the screen mesh of the heat pipe using SiO2-water nanofluids is found. This may be one reason for reinforcing the heat transfer performance of the miniature heat pipe.

Hybrid sodium heat pipe receivers for dish/Stirling systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laing, D.; Reusch, M.

1997-12-31

The design of a hybrid solar/gas heat pipe receiver for the SBP 9 kW dish/Stirling system using a United Stirling AB V160 Stirling engine and the results of on-sun testing in alternative and parallel mode will be reported. The receiver is designed to transfer a thermal power of 35 kW. The heat pipe operates at around 800 C, working fluid is sodium. Operational options are solar-only, gas augmented and gas-only mode. Also the design of a second generation hybrid heat pipe receiver currently developed under a EU-funded project, based on the experience gained with the first hybrid receiver, will bemore » reported. This receiver is designed for the improved SPB/L. and C.-10 kW dish/Stirling system with the reworked SOLO V161 Stirling engine.« less

Slow crack growth test method for polyethylene gas pipes. Volume 1. Topical report, December 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leis, B.; Ahmad, J.; Forte, T.

1992-12-01

In spite of the excellent performance record of polyethylene (PE) pipes used for gas distribution, a small number of leaks occur in distribution systems each year because of slow growth of cracks through pipe walls. The Slow Crack Growth Test (SCG) has been developed as a key element in a methodology for the assessment of the performance of polyethylene gas distribution systems to resist such leaks. This tropical report describes work conducted in the first part of the research directed at the initial development of the SCG test, including a critical evaluation of the applicability of the SCG test asmore » an element in PE gas pipe system performance methodology. Results of extensive experiments and analysis are reported. The results show that the SCG test should be very useful in performance assessment.« less

A study on fatigue strength reduction factor for small diameter socket welded pipe joints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higuchi, Makoto; Nakagawa, Akira; Hayashi, Makoto

1996-12-01

Factors that may exert influence on the fatigue strength of small diameter socket welded joints of nominal diameter in the 20--50 mm range have been investigated by the fully reversed four-point bending fatigue test with the material, diameter, pipe schedule, throat depth, bead shape, slip-on gap, and root defect as the testing parameters. The fatigue strength of socket joints depended acutely on the diameter. When the diameter is large, the fatigue strength tended to be low and the fracture is of the root-failure mode; when it is small, on the other hand, the fatigue strength is high and the fracturemore » is of the toe-failure mode. Stainless steel proved to be superior to carbon steel; it gave rise to 1.37 times the fatigue strength of the latter for socket joints of nominal diameter 50 mm; the fatigue strength reduction factor determined at 10{sup 7} cycles with respect to the fatigue strength of smooth base metal in the fully reversed fatigue was about 4 for stainless steel and about 5 for carbon steel. The fatigue strength was higher, the larger the Sche number (i.e., the thicker the pipe wall); it was improved markedly by placing one final refinement pass on the toe or by eliminating the slip-on gap. An empirical formula relating the size of the root defect to the fatigue strength reduction has been proposed.« less

Analysis of the Earthquake Impact towards water-based fire extinguishing system

NASA Astrophysics Data System (ADS)

Lee, J.; Hur, M.; Lee, K.

2015-09-01

Recently, extinguishing system installed in the building when the earthquake occurred at a separate performance requirements. Before the building collapsed during the earthquake, as a function to maintain a fire extinguishing. In particular, the automatic sprinkler fire extinguishing equipment, such as after a massive earthquake without damage to piping also must maintain confidentiality. In this study, an experiment installed in the building during the earthquake, the water-based fire extinguishing saw grasp the impact of the pipe. Experimental structures for water-based fire extinguishing seismic construction step by step, and then applied to the seismic experiment, the building appears in the extinguishing of the earthquake response of the pipe was measured. Construction of acceleration caused by vibration being added to the size and the size of the displacement is measured and compared with the data response of the pipe from the table, thereby extinguishing water piping need to enhance the seismic analysis. Define the seismic design category (SDC) for the four groups in the building structure with seismic criteria (KBC2009) designed according to the importance of the group and earthquake seismic intensity. The event of a real earthquake seismic analysis of Category A and Category B for the seismic design of buildings, the current fire-fighting facilities could have also determined that the seismic performance. In the case of seismic design categories C and D are installed in buildings to preserve the function of extinguishing the required level of seismic retrofit design is determined.

Acoustic Emission Based Surveillance System for Prediction of Stress Fractures

DTIC Science & Technology

2007-09-01

aging are susceptible to such fractures in contexts of osteoporosis, diabetes, cerebral palsy, fibrous dysplasia and osteogenesis imperfecta . This...disease, or, healthy people who have excessive exercise regimes (soldiers and athletes) experience these fractures [2]. Stress fractures interrupt

Structural reliability assessment of the Oman India Pipeline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Sharif, A.M.; Preston, R.

1996-12-31

Reliability techniques are increasingly finding application in design. The special design conditions for the deep water sections of the Oman India Pipeline dictate their use since the experience basis for application of standard deterministic techniques is inadequate. The paper discusses the reliability analysis as applied to the Oman India Pipeline, including selection of a collapse model, characterization of the variability in the parameters that affect pipe resistance to collapse, and implementation of first and second order reliability analyses to assess the probability of pipe failure. The reliability analysis results are used as the basis for establishing the pipe wall thicknessmore » requirements for the pipeline.« less

Heat pipe temperature control utilizing a soluble gas absorption reservior

NASA Technical Reports Server (NTRS)

Saaski, E. W.

1976-01-01

A new gas-controlled heat pipe design is described which uses a liquid matrix reservior, or sponge, to replace the standard gas reservior. Reservior volume may be reduced by a factor of five to ten for certain gas-liquid combinations, while retaining the same level of temperature control. Experiments with ammonia, butane, and carbon dioxide control gases with methanol working fluid are discussed.

Speed of Sound versus Temperature Using PVC Pipes Open at Both Ends

ERIC Educational Resources Information Center

Bacon, Michael E.

2012-01-01

In this paper we investigate the speed of sound in air as a function of temperature using a simple and inexpensive apparatus. For this experiment it is essential that the appropriate end corrections be taken into account. In a recent paper the end corrections for 2-in i.d. (5.04-cm) PVC pipes open at both ends were investigated. The air column…

Gas propagation following a sudden loss of vacuum in a pipe cooled by He I and He II.

NASA Astrophysics Data System (ADS)

Garceau, N.; Guo, W.; Dodamead, T.

2017-12-01

Many cryogenic systems around the world are concerned with the sudden catastrophic loss of vacuum for cost, preventative damage, safety or other reasons. The experiments in this paper were designed to simulate the sudden vacuum break in the beam-line pipe of a liquid helium cooled superconducting particle accelerator. This paper expands previous research conducted at the National High Magnetic Field Laboratory and evaluates the differences between normal helium (He I) and superfluid helium (He II). For the experiments, a straight pipe and was evacuated and immersed in liquid helium at 4.2 K and below 2.17 K. Vacuum loss was simulated by opening a solenoid valve on a buffer tank filled nitrogen gas. Gas front arrival was observed by a temperature rise of the tube. Preliminary results suggested that the speed of the gas front through the experiment decreased exponentially along the tube for both normal liquid helium and super-fluid helium. The system was modified to a helical pipe system to increase propagation length. Testing and analysis on these two systems revealed there was minor difference between He I and He II despite the difference between the two distinct helium phases heat transfer mechanisms: convection vs thermal counterflow. Furthermore, the results indicated that the temperature of the tube wall above the LHe bath also plays a significant role in the initial front propagation. More systematic measurements are planned in with the helical tube system to further verify the results.

CFD Application to Flow-Accelerated Corrosion in Feeder Bends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietralik, John M.; Smith, Bruce A.W.

2006-07-01

Feeder piping in CANDU{sup R} plants experiences a thinning degradation mechanism called Flow-Accelerated Corrosion (FAC). The piping is made of carbon steel and has high water flow speeds. Although the water chemistry is highly alkaline with room-temperature pH in a range of 10.0-10.5, the piping has FAC rates exceeding 0.1 mm/year in some locations, e.g., in bends. One of the most important parameters affecting the FAC rate is the mass transfer coefficient for convective mass transport of ferrous ions. The ions are created at the pipe wall as a result of corrosion, diffuse through the oxide layer, and are transportedmore » from the oxide-layer/water interface to the bulk water by mass transport. Consequently, the local flow characteristics contribute to the highly turbulent convective mass transfer. Plant data and laboratory experiments indicate that the mass transfer step dominates FAC under feeder conditions. In this study, the flow and mass transfer in a feeder bend under operating conditions were simulated using the Fluent{sup TM} computer code. Because the flow speed is very high, with the Reynolds numbers in a range of several millions, and because the geometry is complex, experiments in a 1:1 scale were conducted with the main objective to validate flow simulations. The experiments measured pressure at several key locations and visualized the flow. The flow and mass transfer models were validated using available friction-factor and mass transfer correlations and literature experiments on mass transfer in a bend. The validation showed that the turbulence model that best predicts the experiments is the realizable k-{epsilon} model. Other two-equation turbulence models, as well as one-equation models and Reynolds stress models were tried. The near-wall treatment used the non-equilibrium wall functions. The wall functions were modified for surface roughness when necessary. A comparison of the local mass transfer coefficient with measured FAC rate in plant specimens shows very good agreement. Visualization experiments indicate secondary flows in the bends. No boundary layer separation was observed in experiments or in simulations. (authors)« less

DEM Particle Fracture Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Boning; Herbold, Eric B.; Homel, Michael A.

2015-12-01

An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density andmore » packings o the samples are also studied in numerical examples.« less

Predicting mineral precipitation in fractures: The influence of local heterogeneity on the feedback between precipitation and permeability

NASA Astrophysics Data System (ADS)

Jones, T.; Detwiler, R. L.

2016-12-01

Long-term subsurface energy production and contaminant storage strategies often rely on induced-mineralization to control the transport of dissolved ions. In low-permeability rocks, precipitation is most likely to occur in fractures that act as leakage pathways for fluids that are in chemical disequilibrium with the formation minerals. These fractures are commonly idealized as parallel-plate channels with uniform surface mineralogy, and as a result, our predictions often suggest that precipitation leads to fast permeability reduction. However, natural fractures contain both heterogeneous mineralogy and three-dimensional surface roughness, and our understanding of how precipitation affects local permeability in these environments is limited. To examine the impacts of local heterogeneity on the feedback between mineral precipitation and permeability, we performed two long-term experiments in transparent analog fractures: (i) uniform-aperture and (ii) variable-aperture. We controlled the initial heterogeneous surface mineralogy in both experiments by seeding the bottom borosilicate fracture surfaces with randomly distributed clusters of CaCO3 crystals. Continuous flow ISCO pumps injected a well-mixed CaCl2-NaHCO3 solution, log(ΩCaCO3) = 1.44, into the fracture at 0.5 ml/min and transmitted-light techniques provided high-resolution (83 x 83 µm), direct measurements of aperture and fluid transport across the fracture. In experiment (i), precipitation decreased local aperture at discrete CaCO3 reaction sites near the fracture inlet, but transport variations across the fracture remained relatively small due to the initial lack of aperture heterogeneity. In contrast, the feedback between precipitation and aperture in experiment (ii) focused flow into large-aperture, preferential flow paths that contained significantly less CaCO3 area than the fracture scale average. Precipitation-induced aperture reduction in (ii) reduced dissolved ion transport into small-aperture regions of the fracture that were abundant with CaCO3 and led to a 72% decrease in measured precipitation rate. These results suggest that incorporating the effects of local heterogeneity may dramatically improve our ability to predict precipitation-induced permeability alterations in fractured rocks.

Roof Weakening of Hydraulic Fracturing for Control of Hanging Roof in the Face End of High Gassy Coal Longwall Mining: A Case Study

NASA Astrophysics Data System (ADS)

Huang, Bingxiang; Wang, Youzhuang

2016-09-01

The occurence of hanging roof commonly arises in the face end of longwall coal mining under hard roof conditions. The sudden break and subsequent caving of a hanging roof could result in the extrusion of gas in the gob to the face, causing gas concentrations to rise sharply and to increase to over a safety-limited value. A series of linear fracturing-holes of 32 mm diameter were drilled into the roof of the entries with an anchor rig. According to the theory that the gob should be fully filled with the fragmentized falling roof rock, the drilling depth is determined as being 3 5 times the mining height if the broken expansion coefficient takes an empirical value. Considering the general extension range of cracks and the supporting form of the entryway, the spacing distance between two drilling holes is determined as being 1 2 times the crack's range of extension. Using a mounting pipe, a high pressure resistant sealing device of a small diameter-size was sent to the designated location for the high-pressure hydraulic fracturing of the roof rock. The hydraulic fracturing created the main hydro-fracturing crack and airfoil branch cracks in the interior of the roof-rock, transforming the roof structure and weakening the strength of the roof to form a weak plane which accelerated roof caving, and eventually induced the full caving in of the roof in time with the help of ground pressure. For holes deeper than 4 m, retreating hydraulic fracturing could ensure the uniformity of crack extension. Tested and applied at several mines in Shengdong Mining District, the highest ruptured water pressure was found to be 55 MPa, and the hanging roof at the face end was reduced in length from 12 m to less than 1 2 m. This technology has eliminated the risk of the extrusion of gas which has accumulated in the gob.

Laboratory research of fracture geometry in multistage HFF in triaxial state

NASA Astrophysics Data System (ADS)

Bondarenko, T. M.; Hou, B.; Chen, M.; Yan, L.

2017-05-01

Multistage hydraulic fracturing of formation (HFF) in wells with horizontal completion is an efficientmethod for intensifying oil extraction which, as a rule, is used to develop nontraditional collectors. It is assumed that the complicated character of HFF fractures significantly influences the fracture geometry in the rock matrix. Numerous theoretical models proposed to predict the fracture geometry and the character of interaction of mechanical stresses in the multistage HFF have not been proved experimentally. In this paper, we present the results of laboratory modeling of the multistage HFF performed on a contemporary laboratory-scale plant in the triaxial stress state by using a gel-solution as the HFF agent. As a result of the experiment, a fracturing pattern was formed in the cubic specimen of the model material. The laboratory results showed that a nearly plane fracture is formed at the firstHFF stage, while a concave fracture is formed at the second HFF stage. The interaction of the stress fields created by the two principal HFF fractures results in the growth of secondary fractures whose directions turned out to be parallel to the modeled well bore. But this stress interference leads to a decrease in the width of the second principal fracture. It is was discovered that the penny-shaped fracture model is more appropriate for predicting the geometry of HFF fractures in horizontal wells than the two-dimensional models of fracture propagation (PKN model, KGD model). A computational experiment based on the boundary element method was carried out to obtain the qualitative description of the multistage HFF processes. As a result, a mechanical model of fracture propagation was constructed,which was used to obtain the mechanical stress field (the stress contrast) and the fracture opening angle distribution over fracture length and fracture orientation direction. The conclusions made in the laboratory modeling of the multistage HFF technology agree well with the conclusions made in the computational experiment. Special attention must be paid to the design of the HFF stage spacing density in the implementation of the multistage HFF in wells with horizontal completion.

Geophysical Properties of Hard Rock for Investigation of Stress Fields in Deep Mines

NASA Astrophysics Data System (ADS)

Tibbo, M.; Young, R. P.; Schmitt, D. R.; Milkereit, B.

2014-12-01

A complication in geophysical monitoring of deep mines is the high-stress dependency of the physical properties of hard rocks. In-mine observations show anisotropic variability of the in situ P- and S-wave velocities and resistivity of the hard rocks that are likely related to stress field changes. As part of a comprehensive study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, data from in situ monitoring of the seismicity, conductivity, stress, and stress dependent physical properties has been obtain. In-laboratory experiments are also being performed on borehole cores from the Sudbury mines. These experiments will measure the Norite borehole core's properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. Hydraulic fracturing has been successfully implemented in industries such as oil and gas and enhanced geothermal systems, and is currently being investigated as a potential method for preconditioning in mining. However, further research is required to quantify how hydraulic fractures propagate through hard, unfractured rock as well as naturally fractured rock typically found in mines. These in laboratory experiments will contribute to a hydraulic fracturing project evaluating the feasibility and effectiveness of hydraulic fracturing as a method of de-stressing hard rock mines. A tri-axial deformation cell equipped with 18 Acoustic Emission (AE) sensors will be used to bring the borehole cores to a tri-axial state of stress. The cores will then be injected with fluid until the the hydraulic fracture has propagated to the edge of the core, while AE waveforms will be digitized continuously at 10 MHz and 12-bit resolution for the duration of each experiment. These laboratory hydraulic fracture experiments will contribute to understanding how parameters including stress ratio, fluid injection rate, and viscosity, affect the fracturing process.

Effect of Unsaturated Flow Modes on Partitioning Dynamics of Gravity-Driven Flow at a Simple Fracture Intersection: Laboratory Study and Three-Dimensional Smoothed Particle Hydrodynamics Simulations

NASA Astrophysics Data System (ADS)

Kordilla, Jannes; Noffz, Torsten; Dentz, Marco; Geyer, Tobias; Tartakovsky, Alexandre M.

2017-11-01

In this work, we study gravity-driven flow of water in the presence of air on a synthetic surface intersected by a horizontal fracture and investigate the importance of droplet and rivulet flow modes on the partitioning behavior at the fracture intersection. We present laboratory experiments, three-dimensional smoothed particle hydrodynamics (SPH) simulations using a heavily parallelized code, and a theoretical analysis. The flow-rate-dependent mode switching from droplets to rivulets is observed in experiments and reproduced by the SPH model, and the transition ranges agree in SPH simulations and laboratory experiments. We show that flow modes heavily influence the "bypass" behavior of water flowing along a fracture junction. Flows favoring the formation of droplets exhibit a much stronger bypass capacity compared to rivulet flows, where nearly the whole fluid mass is initially stored within the horizontal fracture. The effect of fluid buffering within the horizontal fracture is presented in terms of dimensionless fracture inflow so that characteristic scaling regimes can be recovered. For both cases (rivulets and droplets), the flow within the horizontal fracture transitions into a Washburn regime until a critical threshold is reached and the bypass efficiency increases. For rivulet flows, the initial filling of the horizontal fracture is described by classical plug flow. Meanwhile, for droplet flows, a size-dependent partitioning behavior is observed, and the filling of the fracture takes longer. For the case of rivulet flow, we provide an analytical solution that demonstrates the existence of classical Washburn flow within the horizontal fracture.

Deformation and fracture of thin sheet aluminum-lithium alloys: The effect of cryogenic temperatures

NASA Technical Reports Server (NTRS)

Wagner, John A.; Gangloff, Richard P.

1990-01-01

The objective is to characterize the fracture behavior and to define the fracture mechanisms for new Al-Li-Cu alloys, with emphasis on the role of indium additions and cryogenic temperatures. Three alloys were investigated in rolled product form: 2090 baseline and 2090 + indium produced by Reynolds Metals, and commercial AA 2090-T81 produced by Alcoa. The experimental 2090 + In alloy exhibited increases in hardness and ultimate strength, but no change in tensile yield strength, compared to the baseline 2090 composition in the unstretched T6 condition. The reason for this behavior is not understood. Based on hardness and preliminary Kahn Tear fracture experiments, a nominally peak-aged condition was employed for detailed fracture studies. Crack initiation and growth fracture toughness were examined as a function of stress state and microstructure using J(delta a) methods applied to precracked compact tension specimens in the LT orientation. To date, J(delta a) experiments have been limited to 23 C. Alcoa 2090-T81 exhibited the highest toughness regardless of stress state. Fracture was accompanied by extensive delamination associated with high angle grain boundaries normal to the fatigue precrack surface and progressed microscopically by a transgranular shear mechanism. In contrast the two peak-aged Reynolds alloys had lower toughness and fracture was intersubgranular without substantial delamination. The influences of cryogenic temperature, microstructure, boundary precipitate structure, and deformation mode in governing the competing fracture mechanisms will be determined in future experiments. Results contribute to the development of predictive micromechanical models for fracture modes in Al-Li alloys, and to fracture resistant materials.

Helical comb magnetostrictive patch transducers for inspecting spiral welded pipes using flexural guided waves.

PubMed

Zhang, Xiaowei; Tang, Zhifeng; Lv, Fuzai; Pan, Xiaohong

2017-02-01

A wavefront analysis indicates that a flexural wave propagates at a helix angle with respect to the pipe axis. The expression for calculation of the helix angle for each flexural mode is given, and the helix angle dispersion curves for flexural modes are calculated. According to the new understanding of flexural guided waves, a helical comb magnetostrictive patch transducer (HCMPT) is proposed for selectively exciting a single predominant flexural torsional guided wave in a pipe and inspecting spiral welded pipes using flexural waves. A HCMPT contains a pre-magnetized magnetostrictive patch that is helically coupled with the outer surface of a pipe, and a novel compound comb coil that is wrapped around the helical magnetostrictive patch. The proposed wideband HCMPT possesses the direction control ability. A verification experiment indicates that flexural torsional mode T(3,1) at center frequency f=64kHz is effectively actuated by a HCMPT with 13-degree helix angle. Flexural torsional modes T(N,1) with circumferential order N equals 1-5 are selected to inspect a seamless steel pipe, artificial defects are effectively detected by the proposed HCMPT. A 20-degree HCMPT is adopted to inspect a spiral welded pipe, an artificial notch with cross section loss CSL=2.7% is effectively detected by using flexural waves. Copyright © 2016 Elsevier B.V. All rights reserved.

Studies on the influence of axial bends on ultrasonic guided waves in hollow cylinders (pipes)

NASA Astrophysics Data System (ADS)

Verma, Bhupesh; Balasubramaniam, Krishnan; Rajagopal, Prabhu

2013-01-01

Ultrasonic guided waves in hollow cylinders (pipes) are today widely applied as rapid screening tools in the inspection of straight pipe segments in oil, power generation and petrochemical processing industries. However, the characteristics of guided wave propagation across features such as bends in the pipe network are complicated, hampering a wider application of the developed techniques. Although a growing number of studies in recent years have considered guided wave propagation across elbows and U-type bends, the topic is still not very well understood for a general bend angle φ, mean bend radius R and pipe thickness b. Here we use 3D Finite Element (FE) simulation to illumine the propagation of fundamental guided pipe modes across bends of several different angles φ. Two different bend radius regimes, R/λ ≈ 1 and 10 (where λ denotes the wavelength of the mode studied) are considered, exemplifying 'sharp' and gradual or 'slow' bends. Different typical pipe thicknesses b within these regimes are also studied. The results confirm the expectation that different bend radius regimes affect the waves differently. Further, while as observed in earlier studies, at moderate bend radii, fundamental modes travel almost unaffected by an elbow (bend angle φ = 90 degrees), we find that as the bend angle is reduced, there is a progressively larger extent of mode-conversion. These trends and results are validated using experiments.

In-pipe aerodynamic characteristics of a projectile in comparison with free flight for transonic Mach numbers

NASA Astrophysics Data System (ADS)

Hruschka, R.; Klatt, D.

2018-03-01

The transient shock dynamics and drag characteristics of a projectile flying through a pipe 3.55 times larger than its diameter at transonic speed are analyzed by means of time-of-flight and pipe wall pressure measurements as well as computational fluid dynamics (CFD). In addition, free-flight drag of the 4.5-mm-pellet-type projectile was also measured in a Mach number range between 0.5 and 1.5, providing a means for comparison against in-pipe data and CFD. The flow is categorized into five typical regimes the in-pipe projectile experiences. When projectile speed and hence compressibility effects are low, the presence of the pipe has little influence on the drag. Between Mach 0.5 and 0.8, there is a strong drag increase due to the presence of the pipe, however, up to a value of about two times the free-flight drag. This is exactly where the nose-to-base pressure ratio of the projectile becomes critical for locally sonic speed, allowing the drag to be estimated by equations describing choked flow through a converging-diverging nozzle. For even higher projectile Mach numbers, the drag coefficient decreases again, to a value slightly below the free-flight drag at Mach 1.5. This behavior is explained by a velocity-independent base pressure coefficient in the pipe, as opposed to base pressure decreasing with velocity in free flight. The drag calculated by CFD simulations agreed largely with the measurements within their experimental uncertainty, with some discrepancies remaining for free-flying projectiles at supersonic speed. Wall pressure measurements as well as measured speeds of both leading and trailing shocks caused by the projectile in the pipe also agreed well with CFD.

Fluid Pocket Generation in Response to Heterogeneous Reactivity of a Rock Fracture Under Hydrothermal Conditions

NASA Astrophysics Data System (ADS)

Okamoto, A.; Tanaka, H.; Watanabe, N.; Saishu, H.; Tsuchiya, N.

2017-10-01

Fractures are the location of various water-rock interactions within the Earth's crust; however, the impact of the chemical heterogeneity of fractures on hydraulic properties is poorly understood. We conducted flow-through experiments on the dissolution of granite with a tensile fracture at 350°C and fluid pressure of 20 MPa with confining pressure of 40 MPa. The aperture structures were evaluated by X-ray computed tomography before and after the experiments. Under the experimental conditions, quartz grains dissolve rapidly to produce grain-scale pockets on the fracture surface, whereas altered feldspar grains act as asperities to sustain the open cavities. The fracture contained gouge with large surface area. The feedback between fluid flow and the rapid dissolution of gouge material produced large fluid pockets, whereas permeability did not always increase significantly. Such intense hydrological-chemical interactions could strongly influence the porosity-permeability relationship of fractured reservoirs in the crust.

On Subsurface Fracture Opening and Closure

NASA Astrophysics Data System (ADS)

Wang, Y.

2016-12-01

Mechanistic understanding of fracture opening and closure in geologic media is of significant importance to nature resource extraction and waste management, such as geothermal energy extraction, oil/gas production, radioactive waste disposal, and carbon sequestration and storage). A dynamic model for subsurface fracture opening and closure has been formulated. The model explicitly accounts for the stress concentration around individual aperture channels and the stress-activated mineral dissolution and precipitation. A preliminary model analysis has demonstrated the importance of the stress-activated dissolution mechanism in the evolution of fracture aperture in a stressed geologic medium. The model provides a reasonable explanation for some key features of fracture opening and closure observed in laboratory experiments, including a spontaneous switch from a net permeability reduction to a net permeability increase with no changes in a limestone fracture experiment.

Long-period tilt-induced accelerations associated with hydraulic fracturing

NASA Astrophysics Data System (ADS)

Milkereit, Claus; Dahm, Torsten; Cesca, Simone; Lopez, Jose; Nooshiri, Nima; Zang, Arno

2017-04-01

In 2015, several small scale hydrofracture experiments have been performed in situ from a horizontal borehole in a mine gallery in granitic rock. The hydrofracture experiments were monitored by a bundle of different near field sensors covering a broad range of frequencies (see Zang et al., Geophys. J. Int. (2017) 208, 790-813, doi: 10.1093/gji/ggw430). We installed broad band sensors in the gallery close to the fracture experiments, and observed clear long period transients on the horizontal components, with timing and polarity correlated with the opening and closing of the fractures. We interpret the broadband signals as tilt-induced excursions. The broadband signals have been measured independent whether high frequency acoustic emission have been observed or not during the individual fracture experiments. They are thus an independent measure of the success of a hydrofracture experiment and the parameter of the newly formed cracks. In this study we show that most tilt-induced long-period signals can be modeled by a rectangular crack with constant opening in an elastic full space, as first order approximation. From theoretical forward modeling, we proof that the tilt has a higher sensitivity to resolve the strike of the fracture than the displacement field. With this model, we retrieve the strike of the fractures from the tilt observed at a single sensor. The results indicate that the strike angles of the hydrofractures change systematically with the distance to the gallery wall, indicating a rotation of the principal stresses close to the free surface of the gallery. The rotation trend is similar to the one observed in previous hydrofracture experiments in mines. We compare the strength of the modeled tensile cracks, i.e. opening times crack area, with the volume of the injected fluid, and discuss the general resolving power of tilt signals for source parameter fractures. The temporal evolution of the opening and closure of the fractures is discussed.

Embedded and conventional ultrasonic sensors for monitoring acoustic emission during thermal fatigue

NASA Astrophysics Data System (ADS)

Trujillo, Blaine; Zagrai, Andrei

2016-04-01

Acoustic emission is widely used for monitoring pressure vessels, pipes, critical infrastructure, as well as land, sea and air vehicles. It is one of dominant approaches to explore material degradation under fatigue and events leading to material fracture. Addressing a recent interest in structural health monitoring of space vehicles, a need has emerged to evaluate material deterioration due to thermal fatigue during spacecraft atmospheric reentry. Thermal fatigue experiments were conducted, in which aluminum plates were subjected to localized heating and acoustic emission was monitoring by embedded and conventional acoustic emission sensors positioned at various distances from a heat source. At the same time, surface temperature of aluminum plates was monitored using an IR camera. Acoustic emission counts collected by embedded sensors were compared to counts measured with conventional acoustic emission sensors. Both types of sensors show noticeable increase of acoustic emission activity as localized heating source was applied to aluminum plates. Experimental data demonstrate correlation between temperature increase on the surface of the plates and increase in measured acoustic emission activity. It is concluded that under particular conditions, embedded piezoelectric wafer active sensors can be used for acoustic emission monitoring of thermally-induced structural degradation.

The elderly recognizing themselves as vulnerable to falls in the concreteness of the femoral fracture.

PubMed

Carvalho, César Junior Aparecido de; Bocchi, Silvia Cristina Mangini

2017-04-01

understand the experience of the elderly with falls followed by femoral fracture and elaborate theoretical model of this process of lived experience. qualitative research with theoretical saturation through analysis of the ninth nondirected interview of elderly who underwent such experience. Interviews were recorded, transcribed, and analyzed according to Grounded Theory. three categories emerged (sub-processes): evaluating signs and symptoms of fracture after the fall; feeling sad and insecure with the new condition; and finding oneself susceptible to fractures. From realignment of these categories (sub-processes) we could abstract the central category (process), recognizing oneself as vulnerable to falls in the concreteness of the fracture. the theoretical model considering the Symbolic Interactionism signals the implementation of continued program for fall prevention, with teaching strategies that encourage the elderly to reflect on the concreteness of contexts in which there is risk of occurring injury to their health.

Interface test series: An in situ study of factors affecting the containment of hydraulic fractures

NASA Astrophysics Data System (ADS)

Warpinski, N. R.; Finley, S. J.; Vollendorf, W. C.; Obrien, M.; Eshom, E.

1982-02-01

In situ experiments, which are accessible for direct observation by mineback, were conducted to determine the effect that material-property interfaces and in situ stress differences have on hydraulic fracture propagation and the resultant overall geometry. These experiments show conclusively that a difference in elastic modulus at a geologic interface has little or no effect on crack growth and, therefore, is not a feature which would promote containment of fractures within a specified reservoir zone. However, differences in the in situ stress between adjacent layers is shown to have a considerable influence on fracture propagation. Experiments were conducted in a low modulus ash-fall tuff which contained two layers of high minimum principal in situ stress and which was overlain by a formation with at least a factor of 5 increase in elastic modulus. Fractures were observed to terminate in regions of high minimum principal in situ stress in nearly every case.

Permeability Evolution of Fractured Anhydrite Caused by Chemical and Mechanical Alteration

NASA Astrophysics Data System (ADS)

Detwiler, R. L.; Elkhoury, J. E.; Ameli, P.

2011-12-01

Geologic carbon sequestration requires competent structural seals (caprock) to prevent leakage over decadal time scales. Injection of large volumes of CO2 perturbs the target formation from chemical and mechanical equilibrium leading to the possible creation or enhancement of leakage pathways. We investigate the potential for leakage pathways (fractures) to grow over time under reservoir conditions in a series of anhydrite (Ca2SO4) cores. To simulate a potential leakage event in the laboratory, we fractured and jacketed the cores, and placed them in a flow-through reactor vessel. A high-pressure syringe pump applied confining stresses ranging from 7 to 17 MPa and another syringe pump pushed water through the sample at a constant flow rate with pressure control at the outlet. Effluent was sampled periodically and analyzed for Ca2+ and SO42- using an ion chromatograph. Before and after each experiment, we characterized the surfaces of the fractures using a high-resolution optical profilometer and a scanning electron microscope. Careful alignment of the surfaces during optical profiling allowed reproduction of the fracture aperture before and after each experiment. We present results from several experiments each carried out under different conditions in similar fractured anhydrite cores. One involved a well-mated pre-existing fracture and results showed that the permeability of the fractured core was similar to the intact rock matrix (O(10-18 m2); chemical alteration of the core was largely limited to the inflow face of the core and the fracture surfaces remained largely unaltered. To enhance permeability during subsequent experiments, we imposed a small (380 μm) shear displacement between the fracture surfaces resulting in a four-order-of-magnitude increase in initial permeability. The first of these was run at a constant flow rate of 0.6 ml/min for a period of 7 days. The measured pressure gradient within the core increased slowly for a period of 4 days followed by a rapid increase in differential pressure corresponding to a two-order-of-magnitude decrease in permeability. During the experiment, the diameter of the core decreased by ~300 μm at the inlet and a skin of gypsum (Ca2SO42H2O) was created along the length of the fracture. Dissolution of anhydrite and transition to gypsum of additional anhydrite weakened the fracture surfaces leading to closure of the fracture with a corresponding reduction in aperture and permeability. Additional experiments explore the influence of flow at a lower flow rate, which, in the absence of a large confining stress, has been shown to lead to the development of dissolution channels or wormholes.

Results of the multiwell experiment in situ stresses, natural fractures, and other geological controls on reservoirs

NASA Astrophysics Data System (ADS)

Lorenz, John C.; Warpinski, Norman R.; Teufel, Lawrence W.; Branagan, Paul T.; Sattler, Allan R.; Northrop, David A.

Hundreds of millions of cubic meters of natural gas are locked up in low-permeability, natural gas reservoirs. The Multiwell Experiment (MWX) was designed to characterize such reservoirs, typical of much of the western United States, and to assess and develop a technology for the production of this unconventional resource. Flow-rate tests of the MWX reservoirs indicate a system permeability that is several orders of magnitude higher than laboratory permeability measurements made on matrix-rock sandstones. This enhanced permeability is caused by natural fractures. The single set of fractures present in the reservoirs provides a significant permeability anisotropy that is aligned with the maximum in situ horizontal stress. Hydraulic fractures therefore form parallel to the natural fractures and are consequently an inefficient mechanism for stimulation. Successful stimulation may be possible by perturbing the local stress field with a large hydraulic fracture in one well so that a second hydraulic fracture in an offset well propagates transverse to the natural fracture permeability trend.

Caprock integrity susceptibility to permeable fracture creation

DOE PAGES

Frash, Luke; Carey, James William; Ickes, Timothy Lee; ...

2017-07-14

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

Caprock integrity susceptibility to permeable fracture creation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frash, Luke; Carey, James William; Ickes, Timothy Lee

Caprock leakage is of crucial concern for environmentally and economically sustainable development of carbon dioxide sequestration and utilization operations. One potential leakage pathway is through fractures or faults that penetrate the caprock. In this study, we investigate the permeability induced by fracturing initially intact Marcellus shale outcrop specimens at stressed conditions using a triaxial direct-shear method. Measurements of induced permeability, fracture geometry, displacement, and applied stresses were all obtained at stressed conditions to investigate the coupled processes of fracturing and fluid flow as may occur in the subsurface. Fracture geometry was directly observed at stressed conditions using X-ray radiography video.more » Numerical simulation was performed to evaluate the stress distribution developed in the experiments. Our experiments show that permeability induced by fracturing is strongly dependent on the stresses at which the fractures are created, the magnitude of shearing displacement, and the duration of flow. The strongest permeability contrast was observed when comparing specimens fractured at low stress to others fractured at higher stress. Measureable fracture permeability decreased by up to 7 orders of magnitude over a corresponding triaxial confining stress range of 3.5 MPa to 30 MPa. These results show that increasing stress, depth, and time are all significant permeability inhibitors that may limit potential leakage through fractured caprock.« less

High-Resolution Experimental Investigation of mass transfer enhancement by chemical oxidation from DNAPL entrapped in variable-aperture fractures

NASA Astrophysics Data System (ADS)

Arshadi, M.; Rajaram, H.; Detwiler, R. L.; Jones, T.

2012-12-01

Permanganate oxidation of DNAPL- contaminated fractured rock is an effective remediation technology. Permanganate ion reacts with dissolved DNAPL in a bi-molecular oxidation-reduction reaction. The consumption of dissolved DNAPL in this reaction results in increased concentration gradients away from the free-phase DNAPL, resulting in reaction-enhanced mass transfer, which accelerates contaminant removal. The specific objective of our research was to perform high-resolution non-intrusive experimental studies of permanganate oxidation in a 15.24 × 15.24 cm, transparent, analog, variable-aperture fracture with complex initial TCE entrapped phase geometry. Our experimental system uses light-transmission techniques to accurately measure both fracture aperture and the evolution of individual entrapped DNAPL blobs during the remediation experiments at high resolution (pixel size : 6.2×10-3 cm). Three experiments were performed with different flow rates and permanganate inflow concentrations to observe DNAPL-permanganate interactions across a broader range of conditions. Prior to initiating each experiment, the aperture field within the fracture was measured. The oxidation experiment was initiated by TCE injection into the water saturated fracture till the TCE reached the outflow end, followed by water re-injection through the fracture. The flowing water mobilized some TCE. We continued injection of water till TCE mobilization ceased, leaving behind the residual TCE entrapped within the variable-aperture fracture. Subsequently, permanganate injection through the fracture resulted in propagation of a fingered reaction front into the fracture. We developed image processing algorithms to analyze the evolution of DNAPL phase geometry over the duration of the experiment. The permanganate consumption rate varied significantly within the fracture due to the complex flow and DNAPL concentration fields. Precipitated MnO2 was clearly evident on the downstream side of DNAPL blobs near the inflow boundary indicating high reaction rates in these regions. This behavior is explained by the diversion of permanganate around entrapped DNAPL blobs and downstream advection of dissolved DNAPL. Our results indicate that the total rate of mass transfer from the DNAPL blobs is higher at early times, when not much MnO2 has formed and precipitated. With time, MnO2 precipitation in the fracture leads to changes the aperture field and flow field. Precipitated MnO2 around TCE blobs also decreases the DNAPL accessible surface area. By comparing the results of three experiments, we conclude that low permanganate concentrations and high flow rates lead to more efficient DNAPL remediation, resulting from the fact that under these conditions there would be slower MnO2 formation and less precipitation within the fracture. We also present results on the time-evolution of fracture-scale permanganate consumption and DNAPL removal rates. The experimental observations are being used to develop improved high-resolution numerical models of reactive transport in variable-aperture fractures. The overall goal is to relate the coupled processes of DNAPL removal, permanganate consumption, MnO2 formation and associated changes in aperture and interface area; to derive fracture-scale effective representations of these processes.

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs

PubMed Central

Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM. PMID:29621295

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs.

PubMed

Zhang, Fan; Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM.

Experimental Study of Thermal Energy Storage Characteristics using Heat Pipe with Nano-Enhanced Phase Change Materials

NASA Astrophysics Data System (ADS)

Krishna, Jogi; Kishore, P. S.; Brusly Solomon, A.

2017-08-01

The paper presents experimental investigations to evaluate thermal performance of heat pipe using Nano Enhanced Phase Change Material (NEPCM) as an energy storage material (ESM) for electronic cooling applications. Water, Tricosane and nano enhanced Tricosane are used as energy storage materials, operating at different heating powers (13W, 18W and 23W) and fan speeds (3.4V and 5V) in the PCM cooling module. Three different volume percentages (0.5%, 1% and 2%) of Nano particles (Al2O3) are mixed with Tricosane which is the primary PCM. This experiment is conducted to study the temperature distributions of evaporator, condenser and PCM during the heating as well as cooling. The cooling module with heat pipe and nano enhanced Tricosane as energy storage material found to save higher fan power consumption compared to the cooling module that utilities only a heat pipe.

Intermittent gravity-driven flow of grains through narrow pipes

NASA Astrophysics Data System (ADS)

Alvarez, Carlos A.; de Moraes Franklin, Erick

2017-01-01

Grain flows through pipes are frequently found in various settings, such as in pharmaceutical, chemical, petroleum, mining and food industries. In the case of size-constrained gravitational flows, density waves consisting of alternating high- and low-compactness regions may appear. This study investigates experimentally the dynamics of density waves that appear in gravitational flows of fine grains through vertical and slightly inclined pipes. The experimental device consisted of a transparent glass pipe through which different populations of glass spheres flowed driven by gravity. Our experiments were performed under controlled ambient temperature and relative humidity, and the granular flow was filmed with a high-speed camera. Experimental results concerning the length scales and celerities of density waves are presented, together with a one-dimensional model and a linear stability analysis. The analysis exhibits the presence of a long-wavelength instability, with the most unstable mode and a cut-off wavenumber whose values are in agreement with the experimental results.

Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

NASA Technical Reports Server (NTRS)

Ababneh, Mohammed T.; Tarau, Calin; Anderson, William G.; Farmer, Jeffery T.; Alvarez-Hernandez, Angel R.

2016-01-01

Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

CaSO4 Scale Formation on Vibrated Piping System in the Presence Citric Acid

NASA Astrophysics Data System (ADS)

Mangestiyono, W.; Jamari, J.; Muryanto, S.; Bayuseno, A. P.

2018-02-01

Vibration in many industries commonly generated by the operation mechanical equipment such as extruder, mixer, blower, compressor, turbine, generator etc. Vibration propagates into the floor and attacks the pipe around those mechanical equipment. In this paper, the influence of vibration in a pipe on the CaSO4 scale formation was investigated to understand the effect of vibration on the kinetics, mass of scale, crystal phases and crystal polymorph. To generate vibration force, mechanical equipment was prepared consisted of electrical motor, crankshaft, connecting rod and a vibration table at where test pipe section mounted. Deposition rate increased significantly when the vibration affected to the system i.e. 0.5997 and 1.6705 gr/hr for vibration frequency 4.00 and 8.00 Hz. The addition 10.00 ppm of citric acid declined the deposition rate of 8 Hz experiment from 3.4599 gr/hr to 2.2865 gr/hr.

Complex and open fractures: a straightforward approach to management in the cat.

PubMed

Corr, Sandra

2012-01-01

Cats often present with traumatic injuries of the limbs, including complex and open fractures, frequently as a result of road traffic accidents. On initial assessment, complex and open fractures may appear to require expertise beyond the experience of the general practitioner and, in some cases, referral to a specialist may be indicated or amputation should be considered. Many cases, however, can be managed using straightforward principles. This review describes a logical and practical approach to treating such injuries. It discusses general principles of fracture management, highlights the treatment of open fractures, and describes the use of external skeletal fixation for stabilisation of both open and complex fractures. Most fractures can be stabilised using equipment and expertise available in general practice if the basic principles of fracture fixation are understood and rigorously applied. Many textbooks and journal articles have been published on the management of fractures in companion animals, presenting case studies, case series and original biomechanical research. The simple strategy for managing complex injuries that is provided in this review is based on the published literature and the author's clinical experience.

A permanently installed guided wave system for pipe monitoring

NASA Astrophysics Data System (ADS)

Galvagni, Andrea; Cawley, Peter

2012-04-01

Ultrasonic guided waves are routinely used to inspect pipes. The advantage of this technique is that it enables a fullyvolumetric screening of several metres of pipe from a single transducer location, resulting in substantial time and cost savings. However, it suffers from limitations such as relatively low damage sensitivity and difficulties in dealing with intricate pipe networks; furthermore, for a pipe that is buried, submerged or high up in a plant, access to even a single point can be prohibitively expensive. The use of permanently attached sensors can overcome these limitations since access needs to be obtained only once during installation and they enable the use of baseline subtraction, so that any reading from a sensor can be compared to previous readings. This paper discusses the advantages of baseline subtraction and the challenge of compensating for signal changes due to effects other than the growth of damage. It is shown that the use of baseline subtraction allows significant damage sensitivity improvements, particularly in the vicinity of large reflectors. Data from four years of field experience is backed up by accelerated laboratory testing.

Influence of dimension parameters of the gravity heat pipe on the thermal performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kosa, Ľuboš, E-mail: lubos.kosa@fstroj.uniza.sk; Nemec, Patrik, E-mail: patrik.nemec@fstroj.uniza.sk; Jobb, Marián, E-mail: marian.jobb@fstroj.uniza.sk

Currently the problem with the increasing number of electronic devices is a problem with the outlet Joule heating. Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. Perfect dustproof cooling of electronic components ensures longer life of the equipment. One of more alternatives of heat transfer without the using of mechanical equipment is the use of the heat pipe. Heat pipes are easy to manufacture and maintenance of low input investment cost. The advantage of using the heat pipe is its use inmore » hermetic closed electronic device which is separated exchange of air between the device and the environment. This experiment deals with the influence of changes in the working tube diameter and changing the working fluid on performance parameters. Changing the working fluid and the tube diameter changes the thermal performance of the heat pipe. The result of this paper is finding the optimal diameter with ideal working substance for the greatest heat transfer for 1cm{sup 2} sectional area tube.« less

[Research on controlling iron release of desalted water transmitted in existing water distribution system].

PubMed

Tian, Yi-Mei; Liu, Yang; Zhao, Peng; Shan, Jin-Lin; Yang, Suo-Yin; Liu, Wei

2012-04-01

Desalted water, with strong corrosion characteristics, would possibly lead to serious "red water" when transmitted and distributed in existing municipal water distribution network. The main reason for red water phenomenon is iron release in water pipes. In order to study the methods of controlling iron release in existing drinking water distribution pipe, tubercle analysis of steel pipe and cast iron pipe, which have served the distribution system for 30-40 years, was carried out, the main construction materials were Fe3O4 and FeOOH; and immersion experiments were carried in more corrosive pipes. Through changing mixing volume of tap water and desalted water, pH, alkalinity, chloride and sulfate, the influence of different water quality indexes on iron release were mainly analyzed. Meanwhile, based on controlling iron content, water quality conditions were established to meet with the safety distribution of desalted water: volume ratio of potable water and desalted water should be higher than or equal to 2, pH was higher than 7.6, alkalinity was higher than 200 mg x L(-1).

Removal of unwanted fluid

NASA Astrophysics Data System (ADS)

Subudhi, Sudhakar; Sreenivas, K. R.; Arakeri, Jaywant H.

2013-01-01

This work is concerned with the removal of unwanted fluid through the source-sink pair. The source consists of fluid issuing out of a nozzle in the form of a jet and the sink is a pipe that is kept some distance from the source pipe. Of concern is the percentage of source fluid sucked through the sink. The experiments have been carried in a large glass water tank. The source nozzle diameter is 6 mm and the sink pipe diameter is either 10 or 20 mm. The horizontal and vertical separations and angles between these source and sink pipes are adjustable. The flow was visualized using KMnO4 dye, planer laser induced fluorescence and particle streak photographs. To obtain the effectiveness (that is percentage of source fluid entering the sink pipe), titration method is used. The velocity profiles with and without the sink were obtained using particle image velocimetry. The sink flow rate to obtain a certain effectiveness increase dramatically with lateral separation. The sink diameter and the angle between source and the sink axes don't influence effectiveness as much as the lateral separation.

Reconstruction of gas distribution pipelines in MOZG in Poland using PE and PA pipes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borowicz, W.; Podziemski, T.; Kramek, E.

1996-12-31

MOZG--Warsaw Regional Gas Distribution Company was established in 1856. Now it is one of six gas distribution companies in Poland. Due to steadily increasing safety demands, some of the pipelines will need reconstruction. The majority of the substandard piping is located in urban areas. The company wanted to gain experiences in applying reconstruction technologies using two different plastic materials polyethylene and polyamide. They also wanted to assess the technical and economic practicalities of performing relining processes. A PE project--large diameter polyethylene relining (450 mm) conducted in Warsaw in 1994/95 and PA projects--relining using polyamide pipes, projects conducted in Radom andmore » in Warsaw during 1993 and 1994 are the most interesting and representative for this kind of works. Thanks to the experience obtained whilst carrying out these projects, reconstruction of old gas pipelines has become routine. Now they often use polyethylene relining of smaller diameters and they continue both construction and reconstruction of gas network using PA pipes. This paper presents the accumulated knowledge showing the advantages and disadvantages of applied methods. It describes project design and implementation with details and reports on the necessary preparation work, on site job organization and the most common problems arising during the construction works.« less

Cryogenic thermometry for refrigerant distribution system of JT-60SA

NASA Astrophysics Data System (ADS)

Natsume, K.; Murakami, H.; Kizu, K.; Yoshida, K.; Koide, Y.

2015-12-01

JT-60SA is a fully superconducting fusion experimental device involving Japan and Europe. The cryogenic system supplies supercritical or gaseous helium to superconducting coils through valve boxes or coil terminal boxes and in-cryostat pipes. There are 86 temperature measurement points at 4 K along the distribution line. Resistance temperature sensors will be installed on cooling pipes in vacuum. In this work, two sensor attachment methods, two types of sensor, two thermal anchoring methods, and two sensor fixation materials have been experimentally evaluated in terms of accuracy and mass productivity. Finally, the verification test of thermometry has been conducted using the sample pipe fabricated in the same way to the production version, which has been decided by the comparison experiments. The TVO sensor is attached by the saddle method with Apiezon N grease and the measurement wires made of phosphor bronze are wound on the pipe with Stycast 2850FT as the thermal anchoring. A Cernox sensor is directly immersed in liquid helium as a reference thermometer during the experiment. The measured temperature difference between the attached one and reference one has been within ±15 mK in the range of 3.40-4.73 K. It has satisfies the accuracy requirement of 0.1 K.

Lonely GPFUTV-the movement of water under the action of unknown vacuum

NASA Astrophysics Data System (ADS)

Lin, Weiyi

2013-11-01

In this paper, firstly, the experiment on the flow resistance of the aerated pipe flow is introduced. The experimental research on comparison between different volumes of air entrained is presented. Secondly, the characteristics of gravity pipe flow under the action of Torricelli's vacuum, shortly called as GPFUTV are dissertated, including creative and functional design, fundamental principle, etc. Under the joint action of an unknown vacuum energy and the formation of non-aerated flow the water flow is full-pipe and continuous, high-speed and non-rotational as distinguished from turbulent flow. Thirdly, an appeal in relation to the experimental research, the applied studies and basic theory research is given. For instance, experimental study of Torricelli's experiment phenomenon in the vacuum environment, applied study of the potential for GPFUTV to be developed for deep seawater suction technology and lifting technology for deep ocean mining, theoretical study of flow stability and flow resistance under GPFUTV condition, etc. At last, the famous GPFUTV project is illustrated. 12 years of rigorous and independent survey research.

Features of CO2 fracturing deduced from acoustic emission and microscopy in laboratory experiments

NASA Astrophysics Data System (ADS)

Ishida, Tsuyoshi; Chen, Youqing; Bennour, Ziad; Yamashita, Hiroto; Inui, Shuhei; Nagaya, Yuya; Naoi, Makoto; Chen, Qu; Nakayama, Yoshiki; Nagano, Yu

2016-11-01

We conducted hydraulic fracturing (HF) experiments on 170 mm cubic granite specimens with a 20 mm diameter central hole to investigate how fluid viscosity affects HF process and crack properties. In experiments using supercritical carbon dioxide (SC-CO2), liquid carbon dioxide (L-CO2), water, and viscous oil with viscosity of 0.051-336.6 mPa · s, we compared the results for breakdown pressure, the distribution and fracturing mechanism of acoustic emission, and the microstructure of induced cracks revealed by using an acrylic resin containing a fluorescent compound. Fracturing with low-viscosity fluid induced three-dimensionally sinuous cracks with many secondary branches, which seem to be desirable pathways for enhanced geothermal system, shale gas recovery, and other processes.

Toughness-Dominated Regime of Hydraulic Fracturing in Cohesionless Materials

NASA Astrophysics Data System (ADS)

Germanovich, L. N.; Hurt, R. S.; Ayoub, J.; Norman, W. D.

2011-12-01

This work examines the mechanisms of hydraulic fracturing in cohesionless particulate materials with geotechnical, geological, and petroleum applications. For this purpose, experimental techniques have been developed, and used to quantify the initiation and propagation of hydraulic fractures in saturated particulate materials. The fracturing liquid is injected into particulate materials, which are practically cohesionless. The liquid flow is localized in thin self-propagating crack-like conduits. By analogy we call them 'cracks' or 'hydraulic fractures.' When a fracture propagates in a solid, new surfaces are created by breaking material bonds. Consequently, the material is in tension at the fracture tip. Because the particulate material is already 'fractured,' no new surface is created and no fracturing process per se is involved. Therefore, the conventional fracture mechanics principles cannot be directly applied. Based on the laboratory observations, performed on three particulate materials (Georgia Red Clay, silica flour, and fine sand, and their mixtures), this work offers physical concepts to explain the observed phenomena. The goal is to determine the controlling parameters of fracture behavior and to quantify their effects. An important conclusion of our work is that all parts of the cohesionless particulate material (including the tip zone of hydraulic fracture) are likely to be in compression. The compressive stress state is an important characteristic of hydraulic fracturing in particulate materials with low, or no, cohesion (such as were used in our experiments). At present, two kinematic mechanisms of fracture propagation, consistent with the compressive stress regime, can be offered. The first mechanism is based on shear bands propagating ahead of the tip of an open fracture. The second is based on the tensile strain ahead of the fracture tip and reduction of the effective stresses to zero within the leak-off zone. Scaling indicates that in our experiments, there is a high pressure gradient in the leak-off zone in the direction normal to the fracture. Fluid pressure does not decrease considerably along the fracture, however, due to the relatively wide fracture aperture. This suggests that hydraulically induced fractures in unconsolidated materials may be considered to be within the toughness-dominated regime of hydraulic fracturing. Our results indicate that the primary influence on peak or initiation pressure comes from the remote stresses. However, fracture morphology changes significantly with other chosen parameters (stress, flow rate, rheology and permeability). Additionally, an important characteristic feature of fractures in our experiments is the frequent bluntness of the fracture tip, which suggests that plastic deformation at the fracture tip is important. Modeling shows that large openings at the fracture tip correspond to relatively large 'effective' fracture (surface) energy, which can be orders of magnitude greater than for typical (solid) rocks.

Nano-scale zero valent iron transport in a variable aperture dolomite fracture and a glass fracture

NASA Astrophysics Data System (ADS)

Mondal, P.; Sleep, B. E.; Cui, Z.; Zhou, Z.

2014-12-01

Experiments and numerical simulations are being performed to understand the transport behavior of carboxymethyl cellulose polymer stabilized nano-scale zero valent iron (nZVI) in a variable aperture dolomite rock fracture and a variable aperture glass replica of a fractured slate. The rock fracture was prepared by artificially inducing a fracture in a dolomite block along a stylolite, and the glass fracture was prepared by creating molds with melted glass on two opposing sides of a fractured slate rock block. Both of the fractures were 0.28 m in length and 0.21 m in width. Equivalent hydraulic apertures are about 110 microns for the rock fracture and 250 microns for the glass replica fracture. Sodium bromide and lissamine green B (LGB) serve as conservative tracers in the rock fracture and glass replica fracture, respectively. A dark box set-up with a light source and digital camera is being used to visualize the LGB and CMC-nZVI movement in the glass fracture. Experiments are being performed to determine the effects of water specific discharge and CMC concentration on nZVI transport in the fractures. Transmission electron microscopy, dynamic light scattering, and UV-visual spectrophotometry were performed to determine the stability and characteristics of the CMC-nZVI mixture. The transport of bromide, LGB, CMC, and CMC-nZVI in both fractures is being evaluated through analysis of the effluent concentrations. Time-lapse images are also being captured for the glass fracture. Bromide, LGB, and CMC recoveries have exceeded 95% in both fractures. Significant channeling has been observed in the fractures for CMC transport due to viscous effects.

Evolution of a fracture network in an elastic medium with internal fluid generation and expulsion

NASA Astrophysics Data System (ADS)

Kobchenko, Maya; Hafver, Andreas; Jettestuen, Espen; Renard, François; Galland, Olivier; Jamtveit, Bjørn; Meakin, Paul; Dysthe, Dag Kristian

2014-11-01

A simple and reproducible analog experiment was used to simulate fracture formation in a low-permeability elastic solid during internal fluid/gas production, with the objective of developing a better understanding of the mechanisms that control the dynamics of fracturing, fracture opening and closing, and fluid transport. In the experiment, nucleation, propagation, and coalescence of fractures within an elastic gelatin matrix, confined in a Hele-Shaw cell, occurred due to CO2 production via fermentation of sugar, and it was monitored by optical means. We first quantified how a fracture network develops, and then how intermittent fluid transport is controlled by the dynamics of opening and closing of fractures. The gas escape dynamics exhibited three characteristic behaviors: (1) Quasiperiodic release of gas with a characteristic frequency that depends on the gas production rate but not on the system size. (2) A 1 /f power spectrum for the fluctuations in the total open fracture area over an intermediate range of frequencies (f ), which we attribute to collective effects caused by interaction between fractures in the drainage network. (3) A 1 /f2 power spectrum was observed at high frequencies, which can be explained by the characteristic behavior of single fractures.

Justification of indirect methods of bending stresses polyethylene pipes evaluation

NASA Astrophysics Data System (ADS)

Serebrennikov, A. A.; Serebrennikov, D. A.; Hakimov, Z. R.

2017-10-01

The world and Russian companies have a long experience of the polyethylene pipeline installation and operation. At the same time, the significant attention is paid to the improvement of the relevant machines and the production technology. The polyethylene pipeline installation experience proves that its operation properties (reliability and durability) depend on physical and mechanical characteristics of polyethylene, which should be saved during its installation. Defects can occur, including in cases when the pipe is subjected to the significant bending stresses during installation. To evaluate these stresses, including when exposed to cold weather conditions, an indirect method based on the relationship between strength characteristics and occurred deformations is proposed.

Multispectral imaging of plant stress for detection of CO2 leaking from underground

NASA Astrophysics Data System (ADS)

Rouse, J.; Shaw, J. A.; Repasky, K. S.; Lawrence, R. L.

2008-12-01

Multispectral imaging of plant stress is a potentially useful method of detecting CO2 leaking from underground. During the summers of 2007 and 2008, we deployed a multispectral imager for vegetation sensing as part of an underground CO2 release experiment conducted at the Zero Emission Research and Technology (ZERT) field site near the Montana State University campus in Bozeman, Montana. The imager was mounted on a low tower and observed the vegetation in a region near an underground pipe during a multi-week CO2 release. The imager was calibrated to measure absolute reflectance, from which vegetation indices were calculated as a measure of vegetation health. The temporal evolution of these indices over the course of the experiment show that the vegetation nearest the pipe exhibited more stress than the vegetation located further from the pipe. The imager observed notably increased stress in vegetation at locations exhibiting particularly high flux of CO2 from the ground into the atmosphere. These data from the 2007 and 2008 experiments will be used to demonstrate the utility of a tower-mounted multispectral imaging system for detecting CO2 leakage from below ground with the ability to operate continuously during clear and cloudy conditions.

Variation of brine compositions resulting from flow from matrix or fracture permeability, investigated by high pressure laboratory experiments

NASA Astrophysics Data System (ADS)

Poszwa, A. C.; Coleman, M. L.; Pouya, A.; Ader, M.; Bounenni, A.

2003-04-01

Planning oil production from a chalk reservoir oilfield is difficult because the matrix usually has low permeability despite its high porosity. Most oil is thought to come from fracture porosity but the matrix contribution should increase as compaction occurs during production. To better understand the respective contributions from matrix and fracture, we studied the geochemical characteristics of fluids using high-pressure brine flow experiments on chalk cores. During the experiment axial load was changed relative to confining pressure to induce fractures and to close them again. We used chlorine stable isotope variations to study fluid pathway, because chlorine is a chemically conservative element in sedimentary systems and its isotopes fractionate only with physical processes like diffusion or adsorption that could occur mainly in the chalk matrix. A first experiment was performed on a very porous chalk from Henley (on-shore UK) and using a low-salinity brine. Large variations of brine Cl isotope composition were observed (from -0.56 to +0.08 per mil). The variations were correlated positively with the brine flux through the chalk and the permeability of the rock, both parameters controlled by the rock fracturing. A second experiment used brine with salinity similar to that of seawater. In this case, chemical and isotopic variations were not significant. From the beginning, the chalk structure seems to have been destroyed very quickly (induced fracture porosity collapsed) possibly because of the fluid nature, so that whatever pressure was applied, the permeability did not change significantly. Using Valhall reservoir chalk (offshore Norwegian North Sea) and fluid half the salinity of seawater in a third experiment, we obtained a large range of permeabilities. Brine isotopic trends were very similar on average to those of the first experiment even though variations were smaller (Cl isotopes from -0.09 to +0.29 per mil) and not significantly correlated simply to permeability values. The highest isotopic values were in brine flowed through chalk when the permeability was high and fractures opened; the lowest values were in brine flowed through the chalk when its permeability was reduced by closing fractures and increasing the relative contribution from matrix flow where diffusion processes fractionated chlorine isotopes. From this work it seems that the relative contributions from fracture and matrix permeability in reservoirs can be estimated from the geochemical compositions of brines that flowed from them.

Episodic sediment-discharge events in Cascade Springs, southern Black Hills, South Dakota

USGS Publications Warehouse

Hayes, Timothy Scott

1999-01-01

Cascade Springs is a group of artesian springs in the southern Black Hills, South Dakota, with collective flow of about 19.6 cubic feet per second. Beginning on February 28, 1992, a large discharge of red suspended sediment was observed from two of the six known discharge points. Similar events during 1906-07 and 1969 were documented by local residents and newspaper accounts. Mineralogic and grain-size analyses were performed to identify probable subsurface sources of the sediment. Geochemical modeling was performed to evaluate the geochemical evolution of water discharged from Cascade Springs. Interpretations of results provide a perspective on the role of artesian springs in the regional geohydrologic framework. X-ray diffraction mineralogic analyses of the clay fraction of the suspended sediment were compared to analyses of clay-fraction samples taken from nine geologic units at and stratigraphically below the spring-discharge points. Ongoing development of a subsurface breccia pipe(s) in the upper Minnelusa Formation and/or Opeche Shale was identified as a likely source of the suspended sediment; thus, exposed breccia pipes in lower Hell Canyon were examined. Upper Minnelusa Formation breccia pipes in lower Hell Canyon occur in clusters similar to the discrete discharge points of Cascade Springs. Grain-size analyses showed that breccia masses lack clay fractions and have coarser distributions than the wall rocks, which indicates that the red, fine-grained fractions have been carried out as suspended sediment. These findings support the hypothesis that many breccia pipes were formed as throats of abandoned artesian springs. Geochemical modeling was used to test whether geochemical evolution of ground water is consistent with this hypothesis. The evolution of water at Cascade Springs could not be suitably simulated using only upgradient water from the Minnelusa aquifer. A suitable model involved dissolution of anhydrite accompanied by dedolomitization in the upper Minnelusa Formation, which is caused by upward leakage of relatively fresh water from the Madison aquifer. The anhydrite dissolution and dedolomitization account for the net removal of minerals that would lead to breccia pipe formation by gravitational collapse. Breccia pipes in the lower Minnelusa Formation are uncommon; however, networks of interconnected breccia layers and breccia dikes are common. These networks, along with vertical fractures and faults, are likely pathways for transmitting upward leakage from the Madison aquifer. It is concluded that suspended sediment discharged at Cascade Springs probably results from episodic collapse brecciation that is caused by subsurface dissolution of anhydrite beds and cements of the upper Minnelusa Formation, accompanied by replacement of dolomite by calcite. It is further concluded that many breccia pipes probably are the throats of artesian springs that have been abandoned and exposed by erosion. The locations of artesian spring-discharge points probably have been shifting outwards from the center of the Black Hills uplift, essentially keeping pace with regional erosion over geologic time. Thus, artesian springflow probably is a factor in controlling water levels in the Madison and Minnelusa aquifers, with hydraulic head declining over geologic time, in response to development of new discharge points. Development of breccia pipes as throats of artesian springs would greatly enhance vertical hydraulic conductivity in the immediate vicinity of spring-discharge points. Horizontal hydraulic conductivity in the Minnelusa Formation also may be enhanced by dissolution processes related to upward leakage from the Madison aquifer. Potential processes could include dissolution resulting from leakage in the vicinity of breccia pipes that are abandoned spring throats, active spring discharge, development of subsurface breccias with no visible surface expression or spring discharge, as well as general areal leakage

An Experimental Investigation of the Effects of Vacuum Environment on the Fatigue Life, Fatigue-Crack-Growth Behavior, and Fracture Toughness of 7075-T6 Aluminum Alloy. Ph.D. Thesis - North Carolina State Univ.

NASA Technical Reports Server (NTRS)

Hudson, C. M.

1972-01-01

Axial load fatigue life, fatigue-crack propagation, and fracture toughness tests were conducted on 0.090-inch thick specimens made of 7075-T6 aluminum alloy. The fatigue life and fatigue-crack propagation experiments were conducted at a stress ratio of 0.02. Maximum stresses ranged from 33 to 60 ksi in the fatigue life experiments, and from 10 to 40 ksi in the fatigue-crack propagation experiments, and fatigue life experiments were conducted at gas pressures of 760, 0.5, 0.05, and 0.00000005 torr. Fatigue-crack-growth and fracture toughness experiments were conducted at gas pressures of 760 and 5 x 10 to the minus 8th power torr. Residual stress measurements were made on selected fatigue life specimens to determine the effect of such stresses on fatigue life. Analysis of the results from the fatigue life experiments indicated that fatigue life progressively increased as the gas pressure decreased. Analysis of the results from the fatigue-crack-growth experiments indicates that at low values of stress-intensity range, the fatigue crack growth rates were approximately twice as high in air as in vacuum. Fracture toughness data showed there was essentially no difference in the fracture toughness of 7075-T6 in vacuum and in air.

Fundamental Research on Heat Transfer Characteristics in Shell & Tube Type Ice Forming Cold Energy Storage

NASA Astrophysics Data System (ADS)

Saito, Akio; Utaka, Yoshio; Okawa, Seiji; Ishibashi, Hiroaki

Investigation of heat transfer characteristics in an ice making cold energy storage using a set of horizontal cooling pipes was carried out experimentally. Cooling pipe arrangement, number of pipes used and initial water temperature were varied, and temperature distribution in the tank and the volume of ice formed around the pipe were measured. Natural convection was also observed visually. During the experiment, two kinds of layers were observed. One is the layer where ice forming is interfered by natural convection and its temperature decreases rapidly with an almost uniform temperature distribution, and the other is the layer where ice forms steadily under a stagnant water condition. The former was called that the layer is under a cooling process and the latter that the layer is under an ice forming process. The effect of the experimental parameters, such as the arrangement of the cooling pipes, the number of pipes, the initial water temperature and the flow rate of the cooling medium, on the cooling process and the ice forming process were discussed. Approximate analysis was also carried out and compared with the experimental results. Finally, the relationship between the ice packing factor, which is significant in preventing the blockade, and experimental parameters was discussed.

Velocity and stage data collected in a laboratory flume for water-surface slope determination using a pipe manometer

USGS Publications Warehouse

Lee, Jonathan K.; Visser, H.M.; Jenter, H.L.; Duff, M.P.

2000-01-01

U.S. Geological Survey (USGS) hydrologists and ecologist are conducting studies to quantify vegetative flow resistance in order to improve numerical models of surface-water flow in the Florida Everglades. Water-surface slope is perhaps the most difficult of the flow resistance parameters to measure in the Everglades due to the very low gradients of the topography and flow. In an effort to measure these very small slopes, a unique pipe manometer was developed for the local measurement of water-surface slopes on the order of 1 centimeter per kilometer (cm/km). According to theory, a very precise measurement of centerline velocity obtained inside the pipe manometer should serve as a unique proxy for water-surface slope in the direction of the pipe axis. In order to confirm this theoretical relationship and calibrate the pipe manometer, water-surface elevation and pipe centerline velocity data were simultaneously measured in a set of experiments carried out in the tilting flume at the USGS Hydraulic Laboratory Facility at Stennis Space Center, Mississippi. A description of the instrumentation and methods used to evaluate this technique for measuring water-surface slope as well as a summary of the entire data set is presented.

Degradation of specific aromatic compounds migrating from PEX pipes into drinking water.

PubMed

Ryssel, Sune Thyge; Arvin, Erik; Lützhøft, Hans-Christian Holten; Olsson, Mikael Emil; Procházková, Zuzana; Albrechtsen, Hans-Jørgen

2015-09-15

Nine specific compounds identified to migrate from polyethylene (PE) and cross-linked polyethylene (PEX) to drinking water were investigated for their degradation in drinking water. Three sample types were studied: field samples (collected at consumer taps), PEX pipe water extractions, and water samples spiked with target compounds. Four compounds were quantified in field samples at concentrations of 0.15-8.0 μg/L. During PEX pipe water extraction 0.42 ± 0.20 mg NVOC/L was released and five compounds quantified (0.5-6.1 μg/L). The degradation of these compounds was evaluated in PEX-pipe water extractions and spiked samples. 4-ethylphenol was degraded within 22 days. Eight compounds were, however, only partially degradable under abiotic and biotic conditions within the timeframe of the experiments (2-4 weeks). Neither inhibition nor co-metabolism was observed in the presence of acetate or PEX pipe derived NVOC. Furthermore, the degradation in drinking water from four different locations with three different water works was similar. In conclusion, eight out of the nine compounds studied would - if being released from the pipes - reach consumers with only minor concentration decrease during water distribution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe.

PubMed

Zhao, Shanguo; Xu, Guoying; Wang, Ning; Zhang, Xiaosong

2018-01-28

The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties-including the thermal conductivity and viscosity-of nanofluid with various graphene nanoplatelets (GNPs) concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe's start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected.

Integrated Modeling and Experiments to Characterize Coupled Thermo-hydro-geomechanical-chemical processes in Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Viswanathan, H. S.; Carey, J. W.; Karra, S.; Porter, M. L.; Rougier, E.; Kang, Q.; Makedonska, N.; Hyman, J.; Jimenez Martinez, J.; Frash, L.; Chen, L.

2015-12-01

Hydraulic fracturing phenomena involve fluid-solid interactions embedded within coupled thermo-hydro-mechanical-chemical (THMC) processes over scales from microns to tens of meters. Feedbacks between processes result in complex dynamics that must be unraveled if one is to predict and, in the case of unconventional resources, facilitate fracture propagation, fluid flow, and interfacial transport processes. The proposed work is part of a broader class of complex systems involving coupled fluid flow and fractures that are critical to subsurface energy issues, such as shale oil, geothermal, carbon sequestration, and nuclear waste disposal. We use unique LANL microfluidic and triaxial core flood experiments integrated with state-of-the-art numerical simulation to reveal the fundamental dynamics of fracture-fluid interactions to characterize the key coupled processes that impact hydrocarbon production. We are also comparing CO2-based fracturing and aqueous fluids to enhance production, greatly reduce waste water, while simultaneously sequestering CO2. We will show pore, core and reservoir scale simulations/experiments that investigate the contolling mechanisms that control hydrocarbon production.

Effect of Speed (Centrifugal Load) on Gear Crack Propagation Direction

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2001-01-01

The effect of rotational speed (centrifugal force) on gear crack propagation direction was explored. Gears were analyzed using finite element analysis and linear elastic fracture mechanics. The analysis was validated with crack propagation experiments performed in a spur gear fatigue rig. The effects of speed, rim thickness, and initial crack location on gear crack propagation direction were investigated. Crack paths from the finite element method correlated well with those deduced from gear experiments. For the test gear with a backup ratio (rim thickness divided by tooth height) of nib = 0.5, cracks initiating in the tooth fillet propagated to rim fractures when run at a speed of 10,000 rpm and became tooth fractures for speeds slower than 10,000 rpm for both the experiments and anal sis. From additional analysis, speed had little effect on crack propagation direction except when initial crack locations were near the tooth/rim fracture transition point for a given backup ratio. When at that point, higher speeds tended to promote rim fracture while lower speeds (or neglecting centrifugal force) produced tooth fractures.

The dependence of chlorine decay and DBP formation kinetics on pipe flow properties in drinking water distribution.

PubMed

Zhao, Yingying; Yang, Y Jeffrey; Shao, Yu; Neal, Jill; Zhang, Tuqiao

2018-04-27

Simultaneous chlorine decay and disinfection byproduct (DBP) formation have been discussed extensively because of their regulatory and operational significance. This study further examines chemical reaction variability in the water quality changes under various hydrodynamic conditions in drinking water distribution. The variations of kinetic constant for overall chlorine decay (k E ) and trihalomethane (THM) formation were determined under stagnant to turbulent flows using three devices of different wall demand and two types of natural organic matters (NOM) in water. The results from the comparative experiments and modeling analyses show the relative importance of wall demand (k w ), DBP-forming chlorine decay (k D ), and other bulk demand (k b ' ) for pipe flows of Re = 0-52500. It is found that chlorine reactivity of virgin NOM is the overriding factor. Secondly, for tap water NOM of lower reactivity, pipe flow properties (Re or u) can significantly affect k E , the THM yield (T), formation potential (Y), and the time to reach the maximum THM concentration (t max ) through their influence on kinetic ratio k D (k b ' +k w ). These observations, corroborating with turbidity variations during experiments, cannot be explained alone by chlorine dispersion to and from the pipe wall. Mass exchanges through deposition and scale detachment, most likely being flow-dependent, may have contributed to the overall chlorine decay and DBP formation rates. Thus for the simultaneous occurrence of chlorine decay and DBP formation, model considerations of NOM reactivity, pipe types (wall demand), flow hydraulics, and their interactions are essential. Copyright © 2018 Elsevier Ltd. All rights reserved.

Coupled Fracture and Flow in Shale in Hydraulic Fracturing

NASA Astrophysics Data System (ADS)

Carey, J. W.; Mori, H.; Viswanathan, H.

2014-12-01

Production of hydrocarbon from shale requires creation and maintenance of fracture permeability in an otherwise impermeable shale matrix. In this study, we use a combination of triaxial coreflood experiments and x-ray tomography characterization to investigate the fracture-permeability behavior of Utica shale at in situ reservoir conditions (25-50 oC and 35-120 bars). Initially impermeable shale core was placed between flat anvils (compression) or between split anvils (pure shear) and loaded until failure in the triaxial device. Permeability was monitored continuously during this process. Significant deformation (>1%) was required to generate a transmissive fracture system. Permeability generally peaked at the point of a distinct failure event and then dropped by a factor of 2-6 when the system returned to hydrostatic failure. Permeability was very small in compression experiments (< 1 mD), possibly because of limited fracture connectivity through the anvils. In pure share experiments, shale with bedding planes perpendicular to shear loading developed complex fracture networks with narrow apertures and peak permeability of 30 mD. Shale with bedding planes parallel to shear loading developed simple fractures with large apertures and a peak permeability as high as 1 D. Fracture systems held at static conditions for periods of several hours showed little change in effective permeability at hydrostatic conditions as high as 140 bars. However, permeability of fractured systems was a function of hydrostatic pressure, declining in a pseudo-linear, exponential fashion as pressure increased. We also observed that permeability decreased with increasing fluid flow rate indicating that flow did not follow Darcy's Law, possibly due to non-laminar flow conditions, and conformed to Forscheimer's law. The coupled deformation and flow behavior of Utica shale, particularly the large deformation required to initiate flow, indicates the probable importance of activation of existing fractures in hydraulic fracturing and that these fractures can have adequate permeability for the production of hydrocarbon.

Numerical Simulation Applications in the Design of EGS Collab Experiment 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Henry; White, Mark D.; Fu, Pengcheng

The United States Department of Energy, Geothermal Technologies Office (GTO) is funding a collaborative investigation of enhanced geothermal systems (EGS) processes at the meso-scale. This study, referred to as the EGS Collab project, is a unique opportunity for scientists and engineers to investigate the creation of fracture networks and circulation of fluids across those networks under in-situ stress conditions. The EGS Collab project is envisioned to comprise three experiments and the site for the first experiment is on the 4850 Level (4,850 feet below ground surface) in phyllite of the Precambrian Poorman formation, at the Sanford Underground Research Facility, locatedmore » at the former Homestake Gold Mine, in Lead, South Dakota. Principal objectives of the project are to develop a number of intermediate-scale field sites and to conduct well-controlled in situ experiments focused on rock fracture behavior and permeability enhancement. Data generated during these experiments will be compared against predictions of a suite of computer codes specifically designed to solve problems involving coupled thermal, hydrological, geomechanical, and geochemical processes. Comparisons between experimental and numerical simulation results will provide code developers with direction for improvements and verification of process models, build confidence in the suite of available numerical tools, and ultimately identify critical future development needs for the geothermal modeling community. Moreover, conducting thorough comparisons of models, modelling approaches, measurement approaches and measured data, via the EGS Collab project, will serve to identify techniques that are most likely to succeed at the Frontier Observatory for Research in Geothermal Energy (FORGE), the GTO's flagship EGS research effort. As noted, outcomes from the EGS Collab project experiments will serve as benchmarks for computer code verification, but numerical simulation additionally plays an essential role in designing these meso-scale experiments. This paper describes specific numerical simulations supporting the design of Experiment 1, a field test involving hydraulic stimulation of two fractures from notched sections of the injection borehole and fluid circulation between sub-horizontal injection and production boreholes in each fracture individually and collectively, including the circulation of chilled water. Whereas the mine drift allows for accurate and close placement of monitoring instrumentation to the developed fractures, active ventilation in the drift cooled the rock mass within the experimental volume. Numerical simulations were executed to predict seismic events and magnitudes during stimulation, initial fracture orientations for smooth horizontal wellbores, pressure requirements for fracture initiation from notched wellbores, fracture propagation during stimulation between the injection and production boreholes, tracer travel times between the injection and production boreholes, produced fluid temperatures with chilled water injections, pressure limits on fluid circulation to avoid fracture growth, temperature environment surrounding the 4850 Level drift, and fracture propagation within a stress field altered by drift excavation, ventilation cooling, and dewatering.« less

The break remains – elderly people's experiences of a hip fracture 1 year after discharge.

PubMed

Zidén, Lena; Scherman, Marianne Hansson; Wenestam, Claes-Göran

2010-01-01

To explore experienced long-term consequences of a hip fracture and conceptions of what influences hip fracture recovery among community-living elderly people 1 year after discharge. Fifteen subjects (13 females and 2 males), aged 66-94, were interviewed. The phenomenographic method was used for analysis. Experiences of insecurity and restricted life dominated the interviews. The descriptive categories within experienced consequences of a hip fracture were: (1) isolated life with more restricted activity and fewer social contacts, with the two sub-categories (a) more insecure and afraid and (b) more limited ability to move, (2) disappointed and sad that identity and life have changed and (3) satisfied with the situation or feeling even better than before the fracture. The categories within conceptions of what influences hip fracture recovery were: (4) own mind and actions influence recovery, (5) treatment and actions from others influence recovery and (6) you cannot influence recovery. The findings accentuate that the negative consequences of a hip fracture are substantial and long-lasting. As it strikes mostly elderly people, who may have experienced earlier losses and growing disabilities, a hip fracture could add to the risk of losing important life values. Furthermore, the findings indicate that all health care professionals who meet the patients need to consider the patients' own experiences and possible fear and not merely focus on the physical injury and disabilities.

The change of the inlet geometry of a centrifugal compressor stage and its influence on the compressor performance

NASA Astrophysics Data System (ADS)

Wang, Leilei; Yang, Ce; Zhao, Ben; Lao, Dazhong; Ma, Chaochen; Li, Du

2013-06-01

The impact on the compressor performance is important for designing the inlet pipe of the centrifugal compressor of a vehicle turbocharger with different inlet pipes. First, an experiment was performed to determine the compressor performance from three cases: a straight inlet pipe, a long bent inlet pipe and a short bent inlet pipe. Next, dynamic sensors were installed in key positions to collect the sign of the unsteady pressure of the centrifugal compressor. Combined with the results of numerical simulations, the total pressure distortion in the pipes, the pressure distributions on the blades and the pressure variability in the diffuser are studied in detail. The results can be summarized as follows: a bent pipe results in an inlet distortion to the compressor, which leads to performance degradation, and the effect is more apparent as the mass flow rate increases. The distortion induced by the bent inlet is not only influenced by the distance between the outlet of the bent section and the leading edge of the impeller but also by the impeller rotation. The flow fields in the centrifugal impeller and the diffuser are influenced by a coupling effect produced by the upstream inlet distortion and the downstream blocking effect from the volute tongue. If the inlet geometry is changed, the distributions and the fluctuation intensities of the static pressure on the main blade surface of the centrifugal impeller and in the diffuser are changed accordingly.

Welding Penetration Control of Fixed Pipe in TIG Welding Using Fuzzy Inference System

NASA Astrophysics Data System (ADS)

Baskoro, Ario Sunar; Kabutomori, Masashi; Suga, Yasuo

This paper presents a study on welding penetration control of fixed pipe in Tungsten Inert Gas (TIG) welding using fuzzy inference system. The welding penetration control is essential to the production quality welds with a specified geometry. For pipe welding using constant arc current and welding speed, the bead width becomes wider as the circumferential welding of small diameter pipes progresses. Having welded pipe in fixed position, obviously, the excessive arc current yields burn through of metals; in contrary, insufficient arc current produces imperfect welding. In order to avoid these errors and to obtain the uniform weld bead over the entire circumference of the pipe, the welding conditions should be controlled as the welding proceeds. This research studies the intelligent welding process of aluminum alloy pipe 6063S-T5 in fixed position using the AC welding machine. The monitoring system used a charge-coupled device (CCD) camera to monitor backside image of molten pool. The captured image was processed to recognize the edge of molten pool by image processing algorithm. Simulation of welding control using fuzzy inference system was constructed to simulate the welding control process. The simulation result shows that fuzzy controller was suitable for controlling the welding speed and appropriate to be implemented into the welding system. A series of experiments was conducted to evaluate the performance of the fuzzy controller. The experimental results show the effectiveness of the control system that is confirmed by sound welds.

The Geothermic Fatigue Hydraulic Fracturing Experiment in Äspö Hard Rock Laboratory, Sweden: New Insights Into Fracture Process through In-situ AE Monitoring

NASA Astrophysics Data System (ADS)

Kwiatek, G.; Plenkers, K.; Zang, A.; Stephansson, O.; Stenberg, L.

2016-12-01

The geothermic Fatigue Hydraulic Fracturing (FHF) in situ experiment (Nova project 54-14-1) took place in the Äspö Hard Rock Laboratory/Sweden in a 1.8 Ma old granitic to dioritic rock mass. The experiment aims at optimizing geothermal heat exchange in crystalline rock mass by multistage hydraulic fracturing at 10 m scale. Six fractures are driven by three different water injection schemes (continuous, cyclic, pulse pressurization) inside a 28 m long, horizontal borehole at depth level 410 m. The rock volume subject to hydraulic fracturing and monitored by three different networks with acoustic emission (AE), micro-seismicity and electromagnetic sensors is about 30 m x 30 m x 30 m in size. The 16-channel In-situ AE monitoring network by GMuG monitored the rupture generation and propagation in the frequency range 1000 Hz to 100,000 Hz corresponding to rupture dimensions from cm- to dm-scale. The in-situ AE monitoring system detected and analyzed AE activity in-situ (P- and S-wave picking, localization). The results were used to review the ongoing microfracturing activity in near real-time. The in-situ AE monitoring network successfully recorded and localized 196 seismic events for most, but not all, hydraulic fractures. All AE events detected in-situ occurred during fracturing time periods. The source parameters (fracture sizes, moment magnitudes, static stress drop) of AE events framing injection periods were calculated using the combined spectral fitting/spectra ratio techniques. The AE activity is clustered in space and clearly outline the fractures location, its orientation, and expansion as well as their temporal evolution. The outward migration of AE events away from the borehole is observed. Fractures extend up to 7 m from the injection interval in the horizontal borehole. The fractures orientation and location correlate for most fractures roughly with the results gained by image packer. Clear differences in seismic response between hydraulic fractures in different formations and injection schemes are visible which need further investigation. For further analysis all AE data of fracturing time periods were recorded continuously with 1 MHz sampling frequency per channel.

A study of the effects of phosphates on copper corrosion in drinking water: Copper release, electrochemical, and surface analysis approach

NASA Astrophysics Data System (ADS)

Kang, Young C.

The following work is the study to evaluate the impact of corrosion inhibitors on the copper metal in drinking water and to investigate the corrosion mechanism in the presence and absence of inhibitors. Electrochemical experiments were conducted to understand the effect of specific corrosion inhibitors in synthetic drinking water which was prepared with controlled specific water quality parameters. Water chemistry was studied by Inductively Coupled Plasma--Atomic Emission Spectroscopy (ICP--AES) to investigate the copper leaching rate with time. Surface morphology, crystallinity of corrosion products, copper oxidation status, and surface composition were characterized by various solid surface analysis methods, such as Scanning Electron Microscopy/Energy--Dispersive Spectrometry (SEM/EDS), Grazing-Incidence-angle X-ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ions Mass Spectrometry (ToF-SIMS). The purpose of the first set of experiments was to test various electrochemical techniques for copper corrosion for short term before studying a long term loop system. Surface analysis techniques were carried out to identify and study the corrosion products that form on the fresh copper metal surface when copper coupons were exposed to test solutions for 2 days of experiments time. The second phase of experiments was conducted with a copper pipe loop system in a synthetic tap water over an extended period of time, i.e., 4 months. Copper release and electrochemically measured corrosion activity profiles were monitored carefully with and without corrosion inhibitor, polyphosphate. A correlation between the copper released into the solution and the electrochemically measured corrosion activities was also attempted. To investigate corrosion products on the copper pipe samples, various surface analysis techniques were applied in this study. Especially, static mass spectra acquisition and element distribution mapping were carried out by ToF-SIMS. Dynamic SIMS provided shallow depth profile of corroded copper sample. The third set of the experiments was related to electrochemical noise (EN) measurement through copper coupons to pipes. Calculating corrosion rate of a metal and predicting exactly how long it lasts are problematic since the metal corrosion may be caused by combined corrosion types. Many other metals undergo not only uniform corrosion, but localized corrosion. Uniform corrosion may be conducive for copper pipe to prevent it from further severe corrosion and form passivated film, but localized corrosion causes pinhole leaks and limits the copper pipe applications. The objective of this set of experiment is to discuss the application of electrochemical noise approaches to drinking water copper corrosion problems. Specially, a fundamental description of EN is presented including a discussion of how to interpret the results and technique limitations. Although it was indicated with electrochemical analysis that the corrosion activity was affected by orthophosphate addition in the short-term test, no copper-phosphate complex or compound was found by copper surface characterization. Apparently, orthophosphate can inhibit corrosion by adsorption on the copper surface, but cannot form solid complexes with copper in such a short time, 2 days. When polyphosphate was added into recirculating copper pipe system, copper level increased and polarization resistance decreased. Greenish blue residue on the copper pipe was suspected as copper phosphate complex and corrosion inhibition mechanism was proposed.

Dynamical constraints on kimberlite volcanism

NASA Astrophysics Data System (ADS)

Sparks, R. S. J.; Baker, L.; Brown, R. J.; Field, M.; Schumacher, J.; Stripp, G.; Walters, A.

2006-07-01

Kimberlite volcanism involves the ascent of low viscosity (0.1 to 1 Pa s) and volatile-rich (CO 2 and H 2O) ultrabasic magmas from depths of 150 km or greater. Theoretical models and empirical evidence suggest ascent along narrow (˜1 m) dykes at speeds in the range > 4 to 20 m/s. With typical dyke breadths of 1 to 10 km, magma supply rates are estimated in the range 10 2 to 10 5 m 3/s with eruption durations of many hours to months. Based on observations, theory and experiments we propose a four-stage model for kimberlite eruptions to explain the main geological relationships of kimberlites. In stage I magma reaches the Earth's surface along fissures and erupts explosively due to their high volatile content. The early flow exit conditions are overpressured with choked flow conditions; an exit velocity of ˜200 m/s is estimated as representative. Explosive expansion and near surface overpressures initiate crater and pipe formation from the top downwards. In stage II under-pressures (the difference between the lithostatic pressure and pressure of the erupting mixture) develop within the evolving pipe causing rock bursting at depth, undermining overlying rocks and causing down-faulting and crater rim slumping. Rocks falling into the pipe interior are ejected by the strong explosive flows. Stage II is the erosive stage of pipe formation. As the pipe widens and deepens larger under-pressures develop enhancing pipe wall instability. A critical threshold is reached when the exit pressure falls to one atmosphere. As the pipe widens and deepens further the gas exit velocity declines and ejecta becomes trapped within the pipe, initiating stage III. A fluidised bed of pyroclasts develops within the pipe as the eruption wanes to form typical massive volcaniclastic kimberlite. Marginal breccias represent the transition between stages II and III. After the eruption stage IV is a period of hydrothermal metamorphism (principally serpentinisation) and alteration as the pipe cools and meteoric waters infiltrate the hot pipe fill. Following an eruption an open crater can be filled by kimberlite- and country-rock derived sediments, forming the crater-facies.

A Lenz's law experiment revisited

NASA Astrophysics Data System (ADS)

Sawicki, Charles A.

2000-10-01

A dipole magnet model predicts a terminal velocity VT proportional to 1/n for n attached identical cylindrical magnets dropped down a copper pipe. Experiments show that VT increases approximately linearly with n. The explanation for this difference is presented.

Fracture induced electromagnetic emissions: extending laboratory findings by observations at the geophysical scale

NASA Astrophysics Data System (ADS)

Potirakis, Stelios M.; Contoyiannis, Yiannis; Kopanas, John; Kalimeris, Anastasios; Antonopoulos, George; Peratzakis, Athanasios; Eftaxias, Konstantinos; Nomicos, Constantinos

2014-05-01

Under natural conditions, it is practically impossible to install an experimental network on the geophysical scale using the same instrumentations as in laboratory experiments for understanding, through the states of stress and strain and their time variation, the laws that govern the friction during the last stages of EQ generation, or to monitor (much less to control) the principal characteristics of a fracture process. Fracture-induced electromagnetic emissions (EME) in a wide range of frequency bands are sensitive to the micro-structural chances. Thus, their study constitutes a nondestructive method for the monitoring of the evolution of damage process at the laboratory scale. It has been suggested that fracture induced MHz-kHz electromagnetic (EM) emissions, which emerge from a few days up to a few hours before the main seismic shock occurrence permit a real time monitoring of the damage process during the last stages of earthquake preparation, as it happens at the laboratory scale. Since the EME are produced both in the case of the laboratory scale fracture and the EQ preparation process (geophysical scale fracture) they should present similar characteristics in these two scales. Therefore, both the laboratory experimenting scientists and the experimental scientists studying the pre-earthquake EME could benefit from each- other's results. Importantly, it is noted that when studying the fracture process by means of laboratory experiments, the fault growth process normally occurs violently in a fraction of a second. However, a major difference between the laboratory and natural processes is the order-of-magnitude differences in scale (in space and time), allowing the possibility of experimental observation at the geophysical scale for a range of physical processes which are not observable at the laboratory scale. Therefore, the study of fracture-induced EME is expected to reveal more information, especially for the last stages of the fracture process, when it is conducted at the geophysical scale. As a characteristic example, we discuss about the case of electromagnetic silence before the global rupture that was first observed in preseismic EME and recently was also observed in the EME measured during laboratory fracture experiments, completely revising the earlier views about the fracture-induced electromagnetic emissions.

Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

PubMed

Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

2016-08-12

Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs.

Hydraulic fracturing in granite under geothermal conditions

USGS Publications Warehouse

Solberg, P.; Lockner, D.; Byerlee, J.D.

1980-01-01

The experimental hydraulic fracturing of granite under geothermal conditions produces tensile fracture at rapid fluid injection rates and shear fracture at slow injection rates and elevated differential stress levels. A sudden burst of acoustic emission activity accompanies tensile fracture formation whereas the acoustic emission rate increases exponentially prior to shear fracture. Temperature does not significantly affect the failure mechanism, and the experimental results have not demonstrated the occurrence of thermal fracturing. A critical result of these experiments is that fluid injection at intermediate rates and elevated differential stress levels increases permeability by more than an order of magnitude without producing macroscopic fractures, and low-level acoustic emission activity occurs simultaneously near the borehole and propagates outward into the specimen with time. Permeability measurements conducted at atmospheric pressure both before and after these experiments show that increased permeability is produced by permanent structural changes in the rock. Although results of this study have not demonstrated the occurrence of thermal fracturing, they suggest that fluid injection at certain rates in situ may markedly increase local permeability. This could prove critical to increasing the efficiency of heat exchange for geothermal energy extraction from hot dry rock. ?? 1980.

The graphite deposit at Borrowdale (UK): A catastrophic mineralizing event associated with Ordovician magmatism

NASA Astrophysics Data System (ADS)

Ortega, L.; Millward, D.; Luque, F. J.; Barrenechea, J. F.; Beyssac, O.; Huizenga, J.-M.; Rodas, M.; Clarke, S. M.

2010-04-01

The volcanic-hosted graphite deposit at Borrowdale in Cumbria, UK, was formed through precipitation from C-O-H fluids. The δ 13C data indicate that carbon was incorporated into the mineralizing fluids by assimilation of carbonaceous metapelites of the Skiddaw Group by andesite magmas of the Borrowdale Volcanic Group. The graphite mineralization occurred as the fluids migrated upwards through normal conjugate fractures forming the main subvertical pipe-like bodies. The mineralizing fluids evolved from CO 2-CH 4-H 2O mixtures (XCO 2 = 0.6-0.8) to CH 4-H 2O mixtures. Coevally with graphite deposition, the andesite and dioritic wall rocks adjacent to the veins were intensely hydrothermally altered to a propylitic assemblage. The initial graphite precipitation was probably triggered by the earliest hydration reactions in the volcanic host rocks. During the main mineralization stage, graphite precipitated along the pipe-like bodies due to CO 2 → C + O 2. This agrees with the isotopic data which indicate that the first graphite morphologies crystallizing from the fluid (cryptocrystalline aggregates) are isotopically lighter than those crystallizing later (flakes). Late chlorite-graphite veins were formed from CH 4-enriched fluids following the reaction CH 4 + O 2 → C + 2H 2O, producing the successive precipitation of isotopically lighter graphite morphologies. Thus, as mineralization proceeded, water-generating reactions were involved in graphite precipitation, further favouring the propylitic alteration. The structural features of the pipe-like mineralized bodies as well as the isotopic homogeneity of graphite suggest that the mineralization occurred in a very short period of time.

Experimental analysis of quasi-static and dynamic fracture initiation toughness of gy4 armor steel material

NASA Astrophysics Data System (ADS)

Ren, Peng; Guo, Zitao

Quasi-static and dynamic fracture initiation toughness of gy4 armour steel material are investigated using three point bend specimen. The modified split Hopkinson pressure bar (SHPB) apparatus with digital image correlation (DIC) system is applied to dynamic loading experiments. Full-field deformation measurements are obtained by using DIC to elucidate on the strain fields associated with the mechanical response. A series of experiments are conducted at different strain rate ranging from 10-3 s-1 to 103 s-1, and the loading rate on the fracture initiation toughness is investigated. Specially, the scanning electron microscope imaging technique is used to investigate the fracture failure micromechanism of fracture surfaces. The gy4 armour steel material fracture toughness is found to be sensitive to strain rate and higher for dynamic loading as compared to quasi-static loading. This work is supported by National Nature Science Foundation under Grant 51509115.

Computer assisted surgery in preoperative planning of acetabular fracture surgery: state of the art.

PubMed

Boudissa, Mehdi; Courvoisier, Aurélien; Chabanas, Matthieu; Tonetti, Jérôme

2018-01-01

The development of imaging modalities and computer technology provides a new approach in acetabular surgery. Areas covered: This review describes the role of computer-assisted surgery (CAS) in understanding of the fracture patterns, in the virtual preoperative planning of the surgery and in the use of custom-made plates in acetabular fractures with or without 3D printing technologies. A Pubmed internet research of the English literature of the last 20 years was carried out about studies concerning computer-assisted surgery in acetabular fractures. The several steps for CAS in acetabular fracture surgery are presented and commented by the main author regarding to his personal experience. Expert commentary: Computer-assisted surgery in acetabular fractures is still initial experiences with promising results. Patient-specific biomechanical models considering soft tissues should be developed to allow a more realistic planning.

Pressure drop reduction and heat transfer deterioration of slush nitrogen in triangular and circular pipe flows

NASA Astrophysics Data System (ADS)

Ohira, Katsuhide; Kurose, Kizuku; Okuyama, Jun; Saito, Yutaro; Takahashi, Koichi

2017-01-01

Slush fluids such as slush hydrogen and slush nitrogen are characterized by superior properties as functional thermal fluids due to their density and heat of fusion. In addition to allowing efficient hydrogen transport and storage, slush hydrogen can serve as a refrigerant for high-temperature superconducting (HTS) equipment using MgB2, with the potential for synergistic effects. In this study, pressure drop reduction and heat transfer deterioration experiments were performed on slush nitrogen flowing in a horizontal triangular pipe with sides of 20 mm under the conditions of three different cross-sectional orientations. Experimental conditions consisted of flow velocity (0.3-4.2 m/s), solid fraction (0-25 wt.%), and heat flux (0, 10, and 20 kW/m2). Pressure drop reduction became apparent at flow velocities exceeding about 1.3-1.8 m/s, representing a maximum amount of reduction of 16-19% in comparison with liquid nitrogen, regardless of heating. Heat transfer deterioration was seen at flow velocities of over 1.2-1.8 m/s, for a maximum amount of deterioration of 13-16%. The authors of the current study compared the results for pressure drop reduction and heat transfer deterioration in triangular pipe with those obtained previously for circular and square pipes, clarifying differences in flow and heat transfer properties. Also, a correlation equation was obtained between the slush Reynolds number and the pipe friction factor, which is important in the estimation of pressure drop in unheated triangular pipe. Furthermore, a second correlation equation was derived between the modified slush Reynolds number and the pipe friction factor, enabling the integrated prediction of pressure drop in both unheated triangular and circular pipes.

Impact of eliminating fracture intersection nodes in multiphase compositional flow simulation

NASA Astrophysics Data System (ADS)

Walton, Kenneth M.; Unger, Andre J. A.; Ioannidis, Marios A.; Parker, Beth L.

2017-04-01

Algebraic elimination of nodes at discrete fracture intersections via the star-delta technique has proven to be a valuable tool for making multiphase numerical simulations more tractable and efficient. This study examines the assumptions of the star-delta technique and exposes its effects in a 3-D, multiphase context for advective and dispersive/diffusive fluxes. Key issues of relative permeability-saturation-capillary pressure (kr-S-Pc) and capillary barriers at fracture-fracture intersections are discussed. This study uses a multiphase compositional, finite difference numerical model in discrete fracture network (DFN) and discrete fracture-matrix (DFM) modes. It verifies that the numerical model replicates analytical solutions and performs adequately in convergence exercises (conservative and decaying tracer, one and two-phase flow, DFM and DFN domains). The study culminates in simulations of a two-phase laboratory experiment in which a fluid invades a simple fracture intersection. The experiment and simulations evoke different invading fluid flow paths by varying fracture apertures as oil invades water-filled fractures and as water invades air-filled fractures. Results indicate that the node elimination technique as implemented in numerical model correctly reproduces the long-term flow path of the invading fluid, but that short-term temporal effects of the capillary traps and barriers arising from the intersection node are lost.

Mineral Reactions in Shale Gas Reservoirs: Barite Scale Formation from Reusing Produced Water As Hydraulic Fracturing Fluid.

PubMed

Paukert Vankeuren, Amelia N; Hakala, J Alexandra; Jarvis, Karl; Moore, Johnathan E

2017-08-15

Hydraulic fracturing for gas production is now ubiquitous in shale plays, but relatively little is known about shale-hydraulic fracturing fluid (HFF) reactions within the reservoir. To investigate reactions during the shut-in period of hydraulic fracturing, experiments were conducted flowing different HFFs through fractured Marcellus shale cores at reservoir temperature and pressure (66 °C, 20 MPa) for one week. Results indicate HFFs with hydrochloric acid cause substantial dissolution of carbonate minerals, as expected, increasing effective fracture volume (fracture volume + near-fracture matrix porosity) by 56-65%. HFFs with reused produced water composition cause precipitation of secondary minerals, particularly barite, decreasing effective fracture volume by 1-3%. Barite precipitation occurs despite the presence of antiscalants in experiments with and without shale contact and is driven in part by addition of dissolved sulfate from the decomposition of persulfate breakers in HFF at reservoir conditions. The overall effect of mineral changes on the reservoir has yet to be quantified, but the significant amount of barite scale formed by HFFs with reused produced water composition could reduce effective fracture volume. Further study is required to extrapolate experimental results to reservoir-scale and to explore the effect that mineral changes from HFF interaction with shale might have on gas production.

Bifurcating Particle Swarms in Smooth-Walled Fractures

NASA Astrophysics Data System (ADS)

Pyrak-Nolte, L. J.; Sun, H.

2010-12-01

Particle swarms can occur naturally or from industrial processes where small liquid drops containing thousands to millions of micron-size to colloidal-size particles are released over time from seepage or leaks into fractured rock. The behavior of these particle swarms as they fall under gravity are affected by particle interactions as well as interactions with the walls of the fractures. In this paper, we present experimental results on the effect of fractures on the cohesiveness of the swarm and the formation of bifurcation structures as they fall under gravity and interact with the fracture walls. A transparent cubic sample (100 mm x 100 mm x 100 mm) containing a synthetic fracture with uniform aperture distributions was optically imaged to quantify the effect of confinement within fractures on particle swarm formation, swarm velocity, and swarm geometry. A fracture with a uniform aperture distribution was fabricated from two polished rectangular prisms of acrylic. A series of experiments were performed to determine how swarm movement and geometry are affected as the walls of the fracture are brought closer together from 50 mm to 1 mm. During the experiments, the fracture was fully saturated with water. We created the swarms using two different particle sizes in dilute suspension (~ 1.0% by mass). The particles were 3 micron diameter fluorescent polymer beads and 25 micron diameter soda-lime glass beads. Experiments were performed using swarms that ranged in size from 5 µl to 60 µl. The swarm behavior was imaged using an optical fluorescent imaging system composed of a CCD camera illuminated by a 100 mW diode-pumped doubled YAG laser. As a swarm falls in an open-tank of water, it forms a torroidal shape that is stable as long as no ambient or background currents exist in the water tank. When a swarm is released into a fracture with an aperture less than 5 mm, the swarm forms the torroidal shape but it is distorted because of the presence of the walls. The portions of the torroid closest to the fracture wall experiences more drag that causes the swarm to bifurcate. In fractures with 2.5 mm apertures, swarms were observed to bifurcate 7-10 times over a distance of 70 mm. The length of the branches in the tree-like structures decreased as the swarm progressed through multiple bifurcations. The bifurcation length is related to the distance swarms can travel along fractures. Acknowledgment: The authors wish to acknowledge support of this work by the Geosciences Research Program, Office of Basic Energy Sciences US Department of Energy (DE-FG02-09ER16022).

Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms

NASA Astrophysics Data System (ADS)

Bruthans, Jiri; Svetlik, Daniel; Soukup, Jan; Schweigstillova, Jana; Valek, Jan; Sedlackova, Marketa; Mayo, Alan L.

2012-12-01

In Strelec Quarry, the Czech Republic, an underground conduit network > 300 m long with a volume of ~ 104 m3 and a catchment of 7 km2 developed over 5 years by groundwater flow in Cretaceous marine quartz sandstone. Similar landforms at natural exposures (conduits, slot canyons, undercuts) are stabilized by case hardening and have stopped evolving. The quarry offers a unique opportunity to study conduit evolution in sandstone at local to regional scales, from the initial stage to maturity, and to characterize the erosion processes which may form natural landforms prior to stabilization. A new technique was developed to distinguish erodible and non-erodible sandstone surfaces. Based on measurements of relative erodibility, drilling resistance, ambient and water-saturated tensile strength (TS) at natural and quarry exposures three distinct kinds of surfaces were found. 1) Erodible sandstone exposed at ~ 60% of surfaces in quarry. This sandstone loses as much as 99% of TS when saturated. 2) Sub-vertical fracture surfaces that are non-erodible already prior to exposure at ground surface and which keep considerable TS if saturated. 3) Case hardened surfaces that start to form after exposure. In favorable conditions they became non-erodible and reach the full TS in just 6 years. An increase in the hydraulic gradient from ~ 0.005 to > 0.02 triggered conduit evolution, based on long-term monitoring of water table in 18 wells and inflows to the quarry. Rapidly evolving major conduits are characterized by a channel gradient of ~ 0.01, a flow velocity ~ 40 cm/s and sediment concentration ~ 10 g/l. Flow in openings with a discharge 1 ml/s and hydraulic gradient > 0.05 exceeds the erosion threshold and initiates piping. In the first phase of conduit evolution, fast concentrated flow mobilizes erodible sandstone between sets of parallel fractures in the shallow phreatic zone. In the second phase the conduit opening mainly expands vertically upward into the vadose zone by mass wasting of undercut sandstone slabs. Mass wasting is responsible for > 90% of mobilized sandstone. Sides of the mature conduits are protected by non-erodible fracture surfaces. Natural landforms were probably formed very rapidly by overland flow, piping and possibly fluidization during or at the end of the glacial periods when sandstone was not yet protected by case hardening.

Working Fluids for Increasing Capacities of Heat Pipes

NASA Technical Reports Server (NTRS)

Chao, David F.; Zhang, Nengli

2004-01-01

A theoretical and experimental investigation has shown that the capacities of heat pipes can be increased through suitable reformulation of their working fluids. The surface tensions of all of the working fluids heretofore used in heat pipes decrease with temperature. As explained in more detail below, the limits on the performance of a heat pipe are associated with the decrease in the surface tension of the working fluid with temperature, and so one can enhance performance by reformulating the working fluid so that its surface tension increases with temperature. This improvement is applicable to almost any kind of heat pipe in almost any environment. The heat-transfer capacity of a heat pipe in its normal operating-temperature range is subject to a capillary limit and a boiling limit. Both of these limits are associated with the temperature dependence of surface tension of the working fluid. In the case of a traditional working fluid, the decrease in surface tension with temperature causes a body of the liquid phase of the working fluid to move toward a region of lower temperature, thus preventing the desired spreading of the liquid in the heated portion of the heat pipe. As a result, the available capillary-pressure pumping head decreases as the temperature of the evaporator end of the heat pipe increases, and operation becomes unstable. Water has widely been used as a working fluid in heat pipes. Because the surface tension of water decreases with increasing temperature, the heat loads and other aspects of performance of heat pipes that contain water are limited. Dilute aqueous solutions of long-chain alcohols have shown promise as substitutes for water that can offer improved performance, because these solutions exhibit unusual surface-tension characteristics: Experiments have shown that in the cases of an aqueous solution of an alcohol, the molecules of which contain chains of more than four carbon atoms, the surface tension increases with temperature when the temperature exceeds a certain value. There are also other liquids that have surface tensions that increase with temperature and could be used as working fluids in heat pipes. For example, as a substitute for ammonia, which is the working fluid in some heat pipes, one could use a solution of ammonia and an ionic surfactant.

Characterization of Hydraulic Fractures Growth During the Äspö Hard Rock Laboratory Experiment (Sweden)

NASA Astrophysics Data System (ADS)

López-Comino, J. A.; Cesca, S.; Heimann, S.; Grigoli, F.; Milkereit, C.; Dahm, T.; Zang, A.

2017-11-01

A crucial issue to characterize hydraulic fractures is the robust, accurate and automated detection and location of acoustic emissions (AE) associated with the fracture nucleation and growth process. Waveform stacking and coherence analysis techniques are here adapted using massive datasets with very high sampling (1 MHz) from a hydraulic fracturing experiment that took place 410 m below surface in the Äspö Hard Rock Laboratory (Sweden). We present the results obtained during the conventional, continuous water injection experiment Hydraulic Fracture 2. The resulting catalogue is composed of more than 4000 AEs. Frequency-magnitude distribution from AE magnitudes (MAE) reveals a high b value of 2.4. The magnitude of completeness is also estimated approximately MAE 1.1, and we observe an interval range of MAE between 0.77 and 2.79. The hydraulic fractures growth is then characterized by mapping the spatiotemporal evolution of AE hypocentres. The AE activity is spatially clustered in a prolate ellipsoid, resembling the main activated fracture volume ( 105 m3), where the lengths of the principal axes ( a = 10 m; b = 5 m; c = 4 m) define its size and its orientation can be estimated for a rupture plane (strike 123°, dip 60°). An asymmetric rupture process regarding to the fracturing borehole is clearly exhibited. AE events migrate upwards covering the depth interval between 404 and 414 m. After completing each injection and reinjection phase, the AE activity decreases and appears located in the same area of the initial fracture phase, suggesting a crack-closing effect.

Effects of age and loading rate on equine cortical bone failure.

PubMed

Kulin, Robb M; Jiang, Fengchun; Vecchio, Kenneth S

2011-01-01

Although clinical bone fractures occur predominantly under impact loading (as occurs during sporting accidents, falls, high-speed impacts or other catastrophic events), experimentally validated studies on the dynamic fracture behavior of bone, at the loading rates associated with such events, remain limited. In this study, a series of tests were performed on femoral specimens obtained post-mortem from equine donors ranging in age from 6 months to 28 years. Fracture toughness and compressive tests were performed under both quasi-static and dynamic loading conditions in order to determine the effects of loading rate and age on the mechanical behavior of the cortical bone. Fracture toughness experiments were performed using a four-point bending geometry on single and double-notch specimens in order to measure fracture toughness, as well as observe differences in crack initiation between dynamic and quasi-static experiments. Compressive properties were measured on bone loaded parallel and transverse to the osteonal growth direction. Fracture propagation was then analyzed using scanning electron and scanning confocal microscopy to observe the effects of microstructural toughening mechanisms at different strain rates. Specimens from each horse were also analyzed for dry, wet and mineral densities, as well as weight percent mineral, in order to investigate possible influences of composition on mechanical behavior. Results indicate that bone has a higher compressive strength, but lower fracture toughness when tested dynamically as compared to quasi-static experiments. Fracture toughness also tends to decrease with age when measured quasi-statically, but shows little change with age under dynamic loading conditions, where brittle "cleavage-like" fracture behavior dominates. Copyright © 2010 Elsevier Ltd. All rights reserved.

Environmentally Friendly, Rheoreversible, Hydraulic-fracturing Fluids for Enhanced Geothermal Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Hongbo; Kabilan, Senthil; Stephens, Sean A.

Cost-effective creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the feasibility of enhanced geothermal systems (EGS). Current reservoir stimulation entails adverse environmental impacts and substantial economic costs due to the utilization of large volumes of water “doped” with chemicals including rheology modifiers, scale and corrosion inhibitors, biocides, friction reducers among others where, typically, little or no information of composition and toxicity is disclosed. An environmentally benign, CO2-activated, rheoreversible fracturing fluid has recently been developed that significantly enhances rock permeability at effective stress significantly lower than current technology. We evaluate the potential of this novel fracturingmore » fluid for application on geothermal sites under different chemical and geomechanical conditions, by performing laboratory-scale fracturing experiments with different rock sources under different confining pressures, temperatures, and pH environments. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable Polyallylamine (PAA) represent a highly versatile fracturing fluid technology. This fracturing fluid creates/propagates fracture networks through highly impermeable crystalline rock at significantly lower effective stress as compared to control experiments where no PAA was present, and permeability enhancement was significantly increased for PAA compared to conventional hydraulic fracturing controls. This was evident in all experiments, including variable rock source/type, operation pressure and temperature (over the entire range for EGS applications), as well as over a wide range of formation-water pH values. This versatile novel fracturing fluid technology represents a great alternative to industrially available fracturing fluids for cost-effective and competitive geothermal energy production.« less

Extraoral approach to mandibular condylar fractures: our experience with 100 cases.

PubMed

Colletti, Giacomo; Battista, Valeria Marinella Augusta; Allevi, Fabiana; Giovanditto, Federica; Rabbiosi, Dimitri; Biglioli, Federico

2014-07-01

Mandibular condylar fractures are very common. The current literature contains many indications and methods of treatment. Extraoral approaches are complicated by the need to avoid injury to the facial nerve. On the other hand intraoral approaches can make fracture reduction and/or fixation difficult. The mini-retromandibular approach provides an excellent view of the surgical field, minimises the risk of injury to the facial nerve, and allows rapid and easy management of condylar fractures. We have collected and reviewed our first 100 condylar fractures treated by means of a mini-retromandibular approach. Between June 2006 and June 2012, Eighty-seven patients with extracapsular condylar fractures underwent open reduction and rigid fixation for 100 extracapsular condylar fractures via a mini-retromandibular approach. Dental occlusion and anatomic reduction were restored in all 100 condylar fractures. Postoperative infection developed in three patients. There was one sialocele and one case of plate fracture. Four patients experienced transient palsy of the buccal branch of the facial nerve. No permanent deficit of any facial nerve branch was observed. No patient showed condylar head resorption. Our experience with the treatment of the first 100 condylar fractures using the mini-retromandibular approach has demonstrated that this technique has allowed the Authors to safely manage extracapsular condylar fractures at all levels. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

The Influence of Various Vibration Frequency on Barium Sulfate Scale Formation Of Vibrated Piping System In The Presence Citric Acid

NASA Astrophysics Data System (ADS)

Karaman, N.; Mangestiyono, W.; Muryanto, S.; Jamari, J.; Bayuseno, A. P.

2018-01-01

In this paper, the influence of vibrated piping system for BaSO4 scale formation was investigated. The vibration frequency and presence of citric acid were independent variables determining the kinetics, mass deposit and polymorph of the crystals. Correspondingly, induction time and mass of scale were obtained during the experiments. The crystalline scale was observed by scanning electron microscopy (SEM) and X-Ray Diffraction (XRD) to investigate the morphology and the phase mineral deposits, respectively. This effect indicated that the increase in vibration frequency promoted the increased deposition rate, while the pure barite with a plate-like morphology was produced in the experiments.

Long Duration Exposure Facility (LDEF) low-temperature heat pipe experiment package power system results

NASA Technical Reports Server (NTRS)

Tiller, Smith E.; Sullivan, David

1992-01-01

An overview of a self-contained Direct Energy Transfer Power System which was developed to provide power to the Long Duration Exposure Facility (LDEF) Low-Temperature Heat Pipe Experiment Package is presented. The power system operated successfully for the entire mission. Data recorded by the onboard recorder shows that the system operated within design specifications. Other than unanticipated overcharging of the battery, the power system operated as expected for nearly 32,000 low earth orbit cycles, and was still operational when tested after the LDEF recovery. Some physical damage was sustained by the solar array panels due to micrometeoroid hits, but there were not electrical failures.

BACTERIOPHAGE TRANSPORT IN SANDY SOIL AND FRACTURED TUFF

EPA Science Inventory

Bacteriophage transport was investigated in laboratory column experiments using sandy soil, a controlled field study in a sandy wash, and laboratory experiments using fractured rock. In the soil columns, the phage MS-2 exhibited significant dispersion and was excluded from 35 to ...

Three-dimensional modeling of flow through fractured tuff at Fran Ridge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eaton, R.R.; Ho, C.K.; Glass, RJ.

1996-09-01

Numerical studies have been made of an infiltration experiment at Fran Ridge using the TOUGH2 code to aid in the selection of computational models for performance assessment. The exercise investigates the capabilities of TOUGH2 to model transient flows through highly fractured tuff and provides a possible means of calibration. Two distinctly different conceptual models were used in the TOUGH2 code, the dual permeability model and the equivalent continuum model. The infiltration test modeled involved the infiltration of dyed ponded water for 36 minutes. The 205 gallon infiltration of water observed in the experiment was subsequently modeled using measured Fran Ridgemore » fracture frequencies, and a specified fracture aperture of 285 {micro}m. The dual permeability formulation predicted considerable infiltration along the fracture network, which was in agreement with the experimental observations. As expected, al fracture penetration of the infiltrating water was calculated using the equivalent continuum model, thus demonstrating that this model is not appropriate for modeling the highly transient experiment. It is therefore recommended that the dual permeability model be given priority when computing high-flux infiltration for use in performance assessment studies.« less

Three-dimensional modeling of flow through fractured tuff at Fran Ridge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eaton, R.R.; Ho, C.K.; Glass, R.J.

1996-01-01

Numerical studies have been made of an infiltration experiment at Fran Ridge using the TOUGH2 code to aid in the selection of computational models for performance assessment. The exercise investigates the capabilities of TOUGH2 to model transient flows through highly fractured tuff and provides a possible means of calibration. Two distinctly different conceptual models were used in the TOUGH2 code, the dual permeability model and the equivalent continuum model. The infiltration test modeled involved the infiltration of dyed ponded water for 36 minutes. The 205 gallon filtration of water observed in the experiment was subsequently modeled using measured Fran Ridgemore » fracture frequencies, and a specified fracture aperture of 285 {mu}m. The dual permeability formulation predicted considerable infiltration along the fracture network, which was in agreement with the experimental observations. As expected, minimal fracture penetration of the infiltrating water was calculated using the equivalent continuum model, thus demonstrating that this model is not appropriate for modeling the highly transient experiment. It is therefore recommended that the dual permeability model be given priority when computing high-flux infiltration for use in performance assessment studies.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moulin, D.; Chapuliot, S.; Drubay, B.

For structures like vessels or pipes containing a fluid, the Leak-Before-Break (LBB) assessment requires to demonstrate that it is possible, during the lifetime of the component, to detect a rate of leakage due to a possible defect, the growth of which would result in a leak before-break of the component. This LBB assessment could be an important contribution to the overall structural integrity argument for many components. The aim of this paper is to review some practices used for LBB assessment and to describe how some new R & D results have been used to provide a simplified approach ofmore » fracture mechanics analysis and especially the evaluation of crack shape and size during the lifetime of the component.« less

ELECTRON CLOUD OBSERVATIONS AND CURES IN RHIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

FISCHER,W.; BLASKIEWICZ, M.; HUANG, H.

Since 2001 RHIC has experienced electron cloud effects, which have limited the beam intensity. These include dynamic pressure rises - including pressure instabilities, tune shifts, a reduction of the stability threshold for bunches crossing the transition energy, and possibly incoherent emittance growth. We summarize the main observations in operation and dedicated experiments, as well as countermeasures including baking, NEG coated warm beam pipes, solenoids, bunch patterns, anti-grazing rings, pre-pumped cold beam pipes, scrubbing, and operation with long bunches.

Physical disintegration of toilet papers in wastewater systems: experimental analysis and mathematical modeling.

PubMed

Eren, Beytullah; Karadagli, Fatih

2012-03-06

Physical disintegration of representative toilet papers was investigated in this study to assess their disintegration potential in sewer systems. Characterization of toilet papers from different parts of the world indicated two main categories as premium and average quality. Physical disintegration experiments were conducted with representative products from each category according to standard protocols with improvements. The experimental results were simulated by mathematical model to estimate best-fit values of disintegration rate coefficients and fractional distribution ratios. Our results from mathematical modeling and experimental work show that premium products release more amounts of small fibers and disintegrate more slowly than average ones. Comparison of the toilet papers with the tampon applicators studied previously indicates that premium quality toilet papers present significant potential to persist in sewer pipes. Comparison of turbulence level in our experimental setup with those of partial flow conditions in sewer pipes indicates that drains and small sewer pipes are critical sections where disintegration of toilet papers will be limited. For improvement, requirements for minimum pipe slopes may be increased to sustain transport and disintegration of flushable products in small pipes. In parallel, toilet papers can be improved to disintegrate rapidly in sewer systems, while they meet consumer expectations.

Use of a corrugated beam pipe as a passive deflector for bunch length measurements

NASA Astrophysics Data System (ADS)

Seok, Jimin; Chung, Moses; Kang, Heung-Sik; Min, Chang-Ki; Na, Donghyun

2018-02-01

We report the experimental demonstration of bunch length measurements using a corrugated metallic beam pipe as a passive deflector. The corrugated beam pipe has been adopted for reducing longitudinal chirping after the bunch compressors in several XFEL facilities worldwide. In the meantime, there have been attempts to measure the electron bunch's longitudinal current profile using the dipole wakefields generated in the corrugated pipe. Nevertheless, the bunch shape reconstructed from the nonlinearly deflected beam suffers from significant distortion, particularly near the head of the bunch. In this paper, we introduce an iterative process to improve the resolution of the bunch shape reconstruction. The astra and elegant simulations have been performed for pencil beam and cigar beam cases, in order to verify the effectiveness of the reconstruction process. To overcome the undesirable effects of transverse beam spreads, a measurement scheme involving both the corrugated beam pipe and the spectrometer magnet has been employed, both of which do not require a dedicated (and likely very expensive) rf system. A proof-of-principle experiment was carried out at Pohang Accelerator Laboratory (PAL) Injector Test Facility (ITF), and its results are discussed together with a comparison with the rf deflector measurement.

Flow of High Internal Phase Ratio Emulsions through Pipes

NASA Astrophysics Data System (ADS)

Kostak, K.; Özsaygı, R.; Gündüz, I.; Yorgancıoǧlu, E.; Tekden, E.; Güzel, O.; Sadıklar, D.; Peker, S.; Helvacı, Ş. Ş.

2015-04-01

The flow behavior of W/O type of HIPRE stabilized by hydrogen bonds with a sugar (sorbitol) in the aqueous phase, was studied. Two groups of experiments were done in this work: The effect of wall shear stresses were investigated in flow through pipes of different diameters. For this end, HIPREs prestirred at constant rate for the same duration were used to obtain similar drop size distributions. Existence and extent of elongational viscosity were used as a probe to elucidate the effect of drop size distribution on the flow behavior: HIPREs prestirred for the same duration at different rates were subjected to flow through converging pipes. The experimental flow curves for flow through small cylindrical pipes indicated four different stages: 1) initial increase in the flow rate at low pressure difference, 2) subsequent decrease in the flow rate due to capillary flow, 3) pressure increase after reaching the minimum flow rate and 4) slip flow after a critical pressure difference. HIPREs with sufficient external liquid phase in the plateau borders can elongate during passage through converging pipes. In the absence of liquid stored in the plateau borders, the drops rupture during extension and slip flow takes place without elongation.

Investigation of transient chill down phenomena in tubes using liquid nitrogen

NASA Astrophysics Data System (ADS)

Shukla, A. K.; Sridharan, Arunkumar; Atrey, M. D.

2017-12-01

Chill down of cryogenic transfer lines is a crucial part of cryogenic propulsion as chill down ensures transfer of single phase fluid to the storage tanks of cryogenic engines. It also ensures single phase liquid flow at the start of the engine. Chill down time depends on several parameters such as length of the pipe, pipe diameter, orientation, mass flux etc. To understand the effect of these parameters, experiments are carried out in a set up designed and fabricated at Indian Institute of Technology Bombay using tubes of two different diameters. Experiments are conducted at different inlet pressures and mass flow rate values to understand their effect. Two different pipe sizes are taken to study the effect of variation in diameter on chill down time and quantity of cryogen required. Different orientations are taken to understand their effect on the chill down time, heat transfer coefficient and critical heat flux for the same inlet pressure and mass flux. Pipe inner wall temperature, heat transfer coefficient for different boiling regimes and critical heat flux are calculated based on measured outer surface temperature history for each case. A one dimensional energy conservation equation is solved for transient chill down process considering constant mass flux and inlet pressure to predict the chill down time. Temperature variation during chill down obtained from the numerical simulations are compared with the measured temperature history.

Mode Conversion Behavior of Guided Wave in a Pipe Inspection System Based on a Long Waveguide.

PubMed

Sun, Feiran; Sun, Zhenguo; Chen, Qiang; Murayama, Riichi; Nishino, Hideo

2016-10-19

To make clear the mode conversion behavior of S0-mode lamb wave and SH0-plate wave converting to the longitudinal mode guided wave and torsional mode guided wave in a pipe, respectively, the experiments were performed based on a previous built pipe inspection system. The pipe was wound with an L-shaped plate or a T-shaped plate as the waveguide, and the S0-wave and SH0-wave were excited separately in the waveguide. To carry out the objective, a meander-line coil electromagnetic acoustic transducer (EMAT) for S0-wave and a periodic permanent magnet (PPM) EMAT for SH0-wave were developed and optimized. Then, several comparison experiments were conducted to compare the efficiency of mode conversion. Experimental results showed that the T(0,1) mode, L(0,1) mode, and L(0,2) mode guided waves can be successfully detected when converted from the S0-wave or SH0-wave with different shaped waveguides. It can also be inferred that the S0-wave has a better ability to convert to the T(0,1) mode, while the SH0-wave is easier to convert to the L(0,1) mode and L(0,2) mode, and the L-shaped waveguide has a better efficiency than T-shaped waveguide.

[Testing the efficacy of disinfectants during drinking water treatment. A new experimental set-up at the German EPA (Umweltbundesamt - UBA)].

PubMed

Grützmacher, G; Bartel, H; Althoff, H W; Clemen, S

2007-03-01

A set-up for experiments in the flow-through mode was constructed in order to test the efficacy of substances used for disinfecting water during drinking water treatment. A flow-through mode - in contrast to experiments under stationary conditions (so-called batch experiments) - was chosen, because this experimental design allows experiments to be carried out under constant conditions for an extended time (up to one week) and because efficacy testing is possible repeatedly, simultaneously and under exactly the same conditions for short (about 0.5 min) and also longer (about 47 min) contact times. With this experimental design the effect of biofilms along the inner pipe surfaces can be included in the observations. The construction of the experimental set-up is based on experience with laboratory flow-through systems that were installed by the UBA's drinking water department (formerly Institute for Water-, Soil- and Air Hygiene (WaBoLu) Institute) for testing disinfection with chlorine. In the first step, a test pipe for the simulation of a water works situation was installed. Water of different qualities can be mixed in large volumes beforehand so that the experimental procedure can be run with constant water quality for a minimum of one week. The kinetics of the disinfection reaction can be observed by extracting samples from eight sampling ports situated along the test pipe. In order to assign exact residence times to each of the sampling ports, tracer experiments were performed prior to testing disinfectant efficacy. This paper gives the technical details of the experimental set-up and presents the results of the tracer experiments to provide an introduction with respect to its potential.

Water-hammer pressure waves interaction at cross-section changes in series in viscoelastic pipes

NASA Astrophysics Data System (ADS)

Meniconi, S.; Brunone, B.; Ferrante, M.

2012-08-01

In view of scarcity of both experimental data and numerical models concerning transient behavior of cross-section area changes in pressurized liquid flow, the paper presents laboratory data and numerical simulation of the interaction of a surge wave with a partial blockage by a valve, a single pipe contraction or expansion and a series of pipe contraction/expansion in close proximity.With regard to a single change of cross-section area, laboratory data point out the completely different behavior with respect to one of the partially closed in-line valves with the same area ratio. In fact, for the former the pressure wave interaction is not regulated by the steady-state local head loss. With regard to partial blockages, transient tests have shown that the smaller the length, the more intense the overlapping of pressure waves due to the expansion and contraction in series.Numerically, the need for taking into account both the viscoelasticity and unsteady friction is demonstrated, since the classical water-hammer theory does not simulate the relevant damping of pressure peaks and gives rise to a time shifting between numerical and laboratory data. The transient behavior of a single local head loss has been checked by considering tests carried out in a system with a partially closed in-line valve. As a result, the reliability of the quasi steady-state approach for local head loss simulation has been demonstrated in viscoelastic pipes. The model parameters obtained on the basis of transients carried out in single pipe systems have then been used to simulate transients in the more complex pipe systems. These numerical experiments show the great importance of the length of the small-bore pipe with respect to one of the large-bore pipes. Precisely, until a gradually flow establishes in the small-bore pipe, the smaller such a length, the better the quality of the numerical simulation.

Hydraulic Fracture Extending into Network in Shale: Reviewing Influence Factors and Their Mechanism

PubMed Central

Ren, Lan; Zhao, Jinzhou; Hu, Yongquan

2014-01-01

Hydraulic fracture in shale reservoir presents complex network propagation, which has essential difference with traditional plane biwing fracture at forming mechanism. Based on the research results of experiments, field fracturing practice, theory analysis, and numerical simulation, the influence factors and their mechanism of hydraulic fracture extending into network in shale have been systematically analyzed and discussed. Research results show that the fracture propagation in shale reservoir is influenced by the geological and the engineering factors, which includes rock mineral composition, rock mechanical properties, horizontal stress field, natural fractures, treating net pressure, fracturing fluid viscosity, and fracturing scale. This study has important theoretical value and practical significance to understand fracture network propagation mechanism in shale reservoir and contributes to improving the science and efficiency of shale reservoir fracturing design. PMID:25032240

The Danish Fracture Database can monitor quality of fracture-related surgery, surgeons' experience level and extent of supervision.

PubMed

Andersen, Morten Jon; Gromov, Kiril; Brix, Michael; Troelsen, Anders

2014-06-01

The importance of supervision and of surgeons' level of experience in relation to patient outcome have been demonstrated in both hip fracture and arthroplasty surgery. The aim of this study was to describe the surgeons' experience level and the extent of supervision for: 1) fracture-related surgery in general; 2) the three most frequent primary operations and reoperations; and 3) primary operations during and outside regular working hours. A total of 9,767 surgical procedures were identified from the Danish Fracture Database (DFDB). Procedures were grouped based on the surgeons' level of experience, extent of supervision, type (primary, planned secondary or reoperation), classification (AO Müller), and whether they were performed during or outside regular hours. Interns and junior residents combined performed 46% of all procedures. A total of 90% of surgeries by interns were performed under supervision, whereas 32% of operations by junior residents were unsupervised. Supervision was absent in 14-16% and 22-33% of the three most frequent primary procedures and reoperations when performed by interns and junior residents, respectively. The proportion of unsupervised procedures by junior residents grew from 30% during to 40% (p < 0.001) outside regular hours. Interns and junior residents together performed almost half of all fracture-related surgery. The extent of supervision was generally high; however, a third of the primary procedures performed by junior residents were unsupervised. The extent of unsupervised surgery performed by junior residents was significantly higher outside regular hours. not relevant. The Danish Fracture Database ("Dansk Frakturdatabase") was approved by the Danish Data Protection Agency ID: 01321.

CO2 injection into fractured peridotites: a reactive percolation experiment

NASA Astrophysics Data System (ADS)

Escario, S.; Godard, M.; Gouze, P.; Leprovost, R.; Luquot, L.; Garcia-Rios, M.

2017-12-01

Mantle peridotites have the potential to trap CO2 as carbonates. This process observed in ophiolites and in oceanic environments provides a long term and safe storage for CO2. It occurs as a part of a complex suite of fluid-rock reactions involving silicate dissolution and precipitation of hydrous phases, carbonates and minor phases that may in turn modify the hydrodynamic properties and the reactivity of the reacted rocks. The efficiency and lastingness of the process require the renewal of fluids at the mineral-fluid interface. Fractures are dominant flow paths in exhumed mantle sections. This study aims at better understanding the effect of CO2-enriched saline fluids on hydrodynamic and chemical processes through fractured peridotites. Experiments were performed using the reactive percolation bench ICARE Lab 3 - Géosciences Montpellier. It allows monitoring the permeability changes during experiments. Effluents are recurrently sampled for analysing cation concentration, pH and alkalinity. Reacted rock samples were characterized by high resolution X-ray microtomography (ESRF ID19, Grenoble, France) and SEM. Experiments consisted in injecting CO2-enriched brines (NaCl 0.5 M) at a rate of 6 mL.h-1 into artificially fractured cores (9 mm diameter × 20 mm length) of Oman harzburgites at T=170°C and Ptotal = 25 MPa for up to 2 weeks. Fractures are of few µm apertures with rough walls. Three sets of experiments were performed at increasing value of [CO2] (0, 0.1 and 1 mol/kg). All experiments showed a decrease in permeability followed by steady state regime that can be caused by a decrease in the roughness of fracture walls (dissolution dominated process), thus favouring fracture closing, or by the precipitation of secondary phases. Maximum enrichments in Mg, Fe and Ca of the effluent fluids occur during the first 2 hours of the experiments whereas Si displays a maximum enrichment at t = 20 h, suggesting extensive dissolution. Maximum enrichments are observed with the highest values of the [CO2]. After one day, effluent fluid concentrations decrease and become constant. By analysing both the permeability and the outlet fluid concentration one can investigate the coupling processes controlling the transport and the reaction mechanisms that in turn act at maintaining the circulation in the fractures.

Numerical simulation of water hammer in low pressurized pipe: comparison of SimHydraulics and Lax-Wendroff method with experiment

NASA Astrophysics Data System (ADS)

Himr, D.

2013-04-01

Article describes simulation of unsteady flow during water hammer with two programs, which use different numerical approaches to solve ordinary one dimensional differential equations describing the dynamics of hydraulic elements and pipes. First one is Matlab-Simulink-SimHydraulics, which is a commercial software developed to solve the dynamics of general hydraulic systems. It defines them with block elements. The other software is called HYDRA and it is based on the Lax-Wendrff numerical method, which serves as a tool to solve the momentum and continuity equations. This program was developed in Matlab by Brno University of Technology. Experimental measurements were performed on a simple test rig, which consists of an elastic pipe with strong damping connecting two reservoirs. Water hammer is induced with fast closing the valve. Physical properties of liquid and pipe elasticity parameters were considered in both simulations, which are in very good agreement and differences in comparison with experimental data are minimal.

Steam generator feedwater nozzle transition piece replacement experience at Salem Unit 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patten, D.B.; Perrin, J.S.; Roberts, A.T.

Cracking of steam generator feedwater piping adjacent to the feedwater nozzles has been a recurring problem since 1979 at Salem Unit 1 owned and operated by Public Service Electric and Gas Company. In addition to the cracking problem, erosion-corrosion at the leading edge of the feedwater nozzle thermal sleeve was also observed in 1992. To provide a long-term solution for the pipe cracking and thermal sleeve erosion-corrosion problems, a unique transition piece forging was specially designed, fabricated, and installed for each of the four steam generators during the 1995 outage. This paper discusses the design, fabrication, and installation of themore » transition piece forgings at Salem Unit 1, and the experiences gained from this project. It is believed that these experiences may help other utilities when planning similar replacements in the future.« less

Application experience of grade 10Kh9MFB chromium steel for steam shutoff and control valve bodies

NASA Astrophysics Data System (ADS)

Skorobogatykh, V. N.; Schenkova, I. A.; Danyushevskiy, I. A.; Grin', E. A.; Levkov, L. Ya.; Prudnikov, D. A.; Zhuravlev, D. N.; Bazhenov, A. M.

2017-04-01

In 2014-2015, the engineers of JSC "NPO "TsNIITMash", in cooperation with JSC "Energomash (Chekhov)—ChZEM", developed a technology for manufacturing D u = 250 mm valve bodies from 10Kh9MFB chromium steel by electroslag melting (ESM) and produced their pilot copies within the frame of import substitution program. This article provides results of research into determining the design values of metal characteristics, including short-term mechanical properties at working temperatures and impact and long-term strength. The test specimens have been sampled from the following four zones: bottom, central, branch-pipe, and head. Tensile short-term rupture testing has been performed at temperatures of 350, 450, 500, 550, 600, and 650°C. Testing for long-term strength has been carried out at temperatures of 550, 575, 600, and 625°C and stresses of 156.8, 137.2, 117.6, and 98 MPa. To estimate brittle fracture resistance, impact-strength tests have been run at temperatures of-20 and-10°C; 20 and 50°C. The specimens have been sampled from the middle of the blank section. All short-term mechanical properties and impact strength are in agreement with the requirements imposed on the metal of hot-deformed steam piping made of 10Kh9MFB steel as per TU (Technical Conditions) 14-3R-55-2001. The absence of microliquation of alloying elements and the high homogeneity of chemical composition (as demonstrated with nine specimens) have also been experimentally confirmed. Metallographic analysis has shown that the structure of the tested metal is that of tempered martensite with local areas of tempered bainite. Overall, the microscopic structure of metal is practically the same in all the studied zones. Service-life calculation of pilot valve bodies has proved conformity with the safety-margin regulations. Such properties of electroslag melting blank as long-term strength and allowable stress correspond to the level of deformed metal and to regulations.

The flow of water through culverts.

DOT National Transportation Integrated Search

1926-06-01

This paper presents the results of 3,301 experiments on the flow of water through short conduits such as pipe and box culverts and sluiceways under levees. The experiments were conducted by the Bureau of Public Roads, U.S. Department of Agriculture, ...

Experimental testing and modeling analysis of solute mixing at water distribution pipe junctions.

PubMed

Shao, Yu; Jeffrey Yang, Y; Jiang, Lijie; Yu, Tingchao; Shen, Cheng

2014-06-01

Flow dynamics at a pipe junction controls particle trajectories, solute mixing and concentrations in downstream pipes. The effect can lead to different outcomes of water quality modeling and, hence, drinking water management in a distribution network. Here we have investigated solute mixing behavior in pipe junctions of five hydraulic types, for which flow distribution factors and analytical equations for network modeling are proposed. First, based on experiments, the degree of mixing at a cross is found to be a function of flow momentum ratio that defines a junction flow distribution pattern and the degree of departure from complete mixing. Corresponding analytical solutions are also validated using computational-fluid-dynamics (CFD) simulations. Second, the analytical mixing model is further extended to double-Tee junctions. Correspondingly the flow distribution factor is modified to account for hydraulic departure from a cross configuration. For a double-Tee(A) junction, CFD simulations show that the solute mixing depends on flow momentum ratio and connection pipe length, whereas the mixing at double-Tee(B) is well represented by two independent single-Tee junctions with a potential water stagnation zone in between. Notably, double-Tee junctions differ significantly from a cross in solute mixing and transport. However, it is noted that these pipe connections are widely, but incorrectly, simplified as cross junctions of assumed complete solute mixing in network skeletonization and water quality modeling. For the studied pipe junction types, analytical solutions are proposed to characterize the incomplete mixing and hence may allow better water quality simulation in a distribution network. Published by Elsevier Ltd.

Numerical simulation of X90 UOE pipe forming process

NASA Astrophysics Data System (ADS)

Zou, Tianxia; Ren, Qiang; Peng, Yinghong; Li, Dayong; Tang, Ding; Han, Jianzeng; Li, Xinwen; Wang, Xiaoxiu

2013-12-01

The UOE process is an important technique to manufacture large-diameter welding pipes which are increasingly applied in oil pipelines and offshore platforms. The forming process of UOE mainly consists of five successive operations: crimping, U-forming, O-forming, welding and mechanical expansion, through which a blank is formed into a pipe in a UOE pipe mill. The blank with an appropriate edge bevel is bent into a cylindrical shape by crimping (C-forming), U-forming and O-forming successively. After the O-forming, there is an open-seam between two ends of the plate. Then, the blank is welded by automatic four-electrode submerged arc welding technique. Subsequently, the welded pipe is expanded with a mechanical expander to get a high precision circular shape. The multiple operations in the UOE mill make it difficult to control the quality of the formed pipe. Therefore, process design mainly relies on experience in practical production. In this study, the UOE forming of an API X90 pipe is studied by using finite element simulation. The mechanical properties tests are performed on the API X90 pipeline steel blank. A two-dimensional finite element model under the hypothesis of plane strain condition is developed to simulate the UOE process according to data coming from the workshop. A kinematic hardening model is used in the simulation to take the Bauschinger effect into account. The deformation characteristics of the blank during the forming processes are analyzed. The simulation results show a significant coherence in the geometric configurations comparing with the practical manufacturing.

Establishing well-being after hip fracture: a systematic review and meta-synthesis.

PubMed

Rasmussen, Birgit; Uhrenfeldt, Lisbeth

2016-12-01

This study aimed to identify, appraise, aggregate and synthesize findings of experiences of self-confidence and well-being after hip fracture. The systematic review followed the Joanna Briggs Institute (JBI) guidelines. A three-step literature search strategy was followed. Included studies were critically appraised using the JBI critical appraisal tool. Data were analyzed into a meta-summary and a meta-synthesis using a hermeneutic approach. Twenty-nine studies were included in the analysis. The category "balancing a new life" was illustrated through older people's "adaptations", "adjustments" and "worries". The second category "striving for interaction with new life possibilities" was built on experiences of "supportive interaction", "missing interaction" and "obstacles". The abstraction of the categories into the meta-synthesis "establishing well-being described the process of older people gradually coming to terms with new life conditions". It was a process of building confidence through cooperation with staff. Experiences of well-being were possible after hip fracture. Self-confidence enhanced adaptations and adjustments. Older people strived for an active everyday life where they had a sense of identity. Health professionals can facilitate the establishing of well-being through supportive interaction being aware of vulnerabilities and possibilities. This study provides information that may help in the development of interventions taking into account what is meaningful for older people. Implications for Rehabilitation Both staff and significant others play a significant role during rehabilitation after hip fracture and can give rise to both well-being and suffering. During rehabilitation, experiences of self-efficacy can be important as they support progress and adaptation towards a new way of living. After hip fracture, older people may have worries and can experience a diversity of obstacles. A sensitivity towards these experiences by health care professionals can be a support for older people striving to establish well-being after hip fracture. To enhance functional ability and experiences of independency, it may be important to consider what it is about activities that are meaningful in the lives of older people after a hip fracture.

Preferences of older patient regarding hip fracture rehabilitation service configuration: A feasibility discrete choice experiment.

PubMed

Charles, Joanna M; Roberts, Jessica L; Din, Nafees Ud; Williams, Nefyn H; Yeo, Seow Tien; Edwards, Rhiannon T

2018-05-14

As part of a wider feasibility study, the feasibility of gaining older patients' views for hip fracture rehabilitation services was tested using a discrete choice experiment in a UK context. Discrete choice experiment is a method used for eliciting individuals' preferences about goods and services. The discrete choice experiment was administered to 41 participants who had experienced hip fracture (mean age 79.3 years; standard deviation (SD) 7.5 years), recruited from a larger feasibility study exploring a new multidisciplinary rehabilitation for hip fracture. Attributes and levels for this discrete choice experiment were identified from a systematic review and focus groups. The questionnaire was administered at the 3-month follow-up. Participants indicated a significant preference for a fully-qualified physiotherapist or occupational therapist to deliver the rehabilitation sessions (β = 0·605, 95% confidence interval (95% CI) 0.462-0.879), and for their rehabilitation session to last less than 90 min (β = -0.192, 95% CI -0.381 to -0.051). The design of the discrete choice experiment using attributes associated with service configuration could have the potential to inform service implementation, and assist rehabilitation service design that incorporates the preferences of patients.

Heat transfer experiments with a central receiver tube subjected to unsteady and non-uniform heat flux

NASA Astrophysics Data System (ADS)

Fernández-Torrijos, María; Marugán-Cruz, Carolina; Sobrino, Celia; Santana, Domingo

2017-06-01

In this work, a molten salt test loop to study the heat transfer process in external molten salt receivers is described. The experimental installation is formed by a cylindrical molten salt tank, a pump, a flow meter, and an induction heater to generate the heat flux, which is applied in a small rectangular region of the tube surface. In central tower plants, the external receiver pipe is considered to be under unilateral concentrated solar radiation, because only one side of the pipe receives high heat flux. The main advantage of using an induction heater is the control of heating in different areas of the tube. In order to measure the effects of a non-homogenous and unsteady heat flux on the wall temperature distribution a series of experiments have been carried out. 4 K-type thermocouples have been welded at different axial and azimuthal positions of the pipe to obtain the wall temperature distribution. Different temperature measurements have been made varying the heat flux and water velocity to study their effects on the heat transfer process.

Hydrodynamic and Sediment Responses of Open Channels to Exposed Pipe Encasements

PubMed Central

Mao, J. Q.; Zhang, H. Q.; Dai, H. C.; Yuan, B. H.; Hu, T. F.

2015-01-01

The effects of exposed pipe encasements on the local variation of hydrodynamic and sediment conditions in a river channel are examined. Laboratory experiments are performed to assess the response of water level, flow regime and bed deformation to several representative types of concrete encasements. The experimental conditions considered are: three types of exposed pipe encasements exposed on the bed, including trapezoidal shape, circular-arc shape and polygonal shape, and three sets of discharges, including annual discharge, once-in-3-year flood, and once-in-50-year flood. Our experiments show that: (1) the amount of backwater definitely depends on the encasement geometric shape and the background discharge; (2) smaller discharges generally tend to induce local scour of river bed downstream of the encasement, and the order of sensitivity of bed deformation to the encasement geometric shape is trapezoidal > circular-arc > polygonal; (3) comparatively speaking, the polygonal encasement may be considered as a suitable protective structure for pipelines across alluvial rivers, with relatively modest effects on the local hydrodynamic conditions and bed stabilization. PMID:26588840

Effect of using acetone and distilled water on the performance of open loop pulsating heat pipe (OLPHP) with different filling ratios

NASA Astrophysics Data System (ADS)

Rahman, Md. Lutfor; Afrose, Tonima; Tahmina, Halima Khatun; Rinky, Rumana Parvin; Ali, Mohammad

2016-07-01

Pulsating heat pipe (PHP) is a new innovation in the modern era of miniaturizes thermal management system for its higher heating and cooling capacity. The objective of this experiment is to observe the performance of open loop pulsating heat pipe using two fluids at different filling ratios. This OLPHP is a copper capillary tube of 2.5mm outer diameter and 2mm inner diameter. It consists of 8 loops where the evaporative section is 50mm, adiabatic section is 120mm and condensation section is 80mm. The experiment is conducted with distilled water and acetone at 40%, 50%, 60%, and 70% filling ratios where 0° (vertical) is considered as definite angle of inclination. Distilled water and acetone are selected as working fluids considering their different latent heat of vaporization and surface tension. It is found that acetone shows lower thermal resistance than water at all heat inputs. Best performance of acetone is attained at 70% filling ratio. Water displays better heat transfer capability at 50% filling ratio.

Developing a Fracture Model of the Granite Rocks Around the Research Tunnel at the Mizunami Underground Research Laboratory in Central Japan

NASA Astrophysics Data System (ADS)

Kalinina, E.; Hadgu, T.; Wang, Y.

2017-12-01

The Mizunami Underground Research Laboratory (MIU) is located in Tono area in Central Japan. It is operated by the Japan Atomic Energy Agency (JAEA) with the main purpose of providing scientific basis for the research and development of technologies needed for deep geological disposal of radioactive waste in fractured crystalline rocks. The current work is focused on the research and experiments in the tunnel located at 500 m depth. The data collected in the tunnel and exploratory boreholes were shared with the participants of the DEvelopment of COupled models and their VALidation against EXperiments (DECOVALEX), an international research and model comparison collaboration. This study describes the development of the fracture model representing granite rocks around the research tunnel. The model domain is 100x150x100m with the main experimental part of the tunnel, Closure Test Drift, located approximately in the center. The major input data were the fracture traces measured on the tunnel walls (total of 2,023 fractures), fractures observed in the horizontal borehole parallel to the tunnel, and the packer tests conducted in this borehole and one vertical borehole located within the modeling domain. 78 fractures (the ones with the inflow) in the tunnel were incorporated in the development of the fracture model. Fracture size was derived from the fracture trace analysis. It was shown that the fracture radius followed lognormal distributions. Fracture transmissivity was estimated from an analytical solution of inflow into the tunnel through an individual fracture and the total measured inflow into the tunnel. 16 fractures were incorporated in the model along the horizontal borehole. The packer test data in the different well intervals were used to estimate the range in fracture transmissivity. A relationship between the fracture transmissivity and fracture radius was developed. The fractures in the tunnel and borehole were used to derive fracture orientation and fracture intensity distributions. These distributions were used to generate stochastic fractures outside the tunnel and horizontal borehole. The fracture model was upscaled to an orthogonal continuum mesh with 1x1x1 m3 cell size using Oda's method.

Chlorine decay and bacterial inactivation kinetics in drinking water in the tropics.

PubMed

Thøgersen, J; Dahi, E

1996-09-01

The decay of free chlorine (Cl2) and combined chlorine (mostly monochloramine: NH2Cl) and the inactivation of bacteria was examined in Dar es Salaam, Tanzania. Batch experiments, pilot-scale pipe experiments and full-scale pipe experiments were carried out to establish the kinetics for both decay and inactivation, and to compare the two disinfectants for use under tropical conditions. The decay of both disinfectants closely followed first order kinetics, with respect to the concentration of both disinfectant and disinfectant-consuming substances. Bacterial densities exhibited a kinetic pattern consisting of first order inactivation with respect to the density of the bacteria and the concentration of the disinfectant, and first order growth with respect to the bacterial density. The disinfection kinetic model takes the decaying concentration of the disinfectant into account. The decay rate constant for free chlorine was 114 lg(-1)h(-1), while the decay rate constant for combined chlorine was 1.84 lg(-1)h(-1) (1.6% of the decay rate for free chlorine). The average concentration of disinfectant consuming substances in the water phase was 2.6 mg Cl2/l for free chlorine and 5.6 mg NH2Cl/l for combined chlorine. The decay rate constant and the concentration of disinfectant consuming substances when water was pumped through pipes, depended on whether or not chlorination was continuous. Combined chlorine especially could clean the pipes of disinfectant consuming substances. The inactivation rate constant λ, was estimated at 3.06×10(4) lg(-1)h(-1). Based on the inactivation rate constant, and a growth rate constant determined in a previous study, the critical concentration of free chlorine was found to be 0.08 mg Cl2/l. The critical concentration is a value below which growth rates dominate over inactivation.

Analysis of the fractures of metallic materials using optical coherence tomography

NASA Astrophysics Data System (ADS)

Hutiu, Gh.; Duma, V.-F.; Demian, D.; Bradu, A.; Podoleanu, A. Gh.

2017-06-01

Forensic in situ investigations, for example for aviation, maritime, road, or rail accidents would benefit from a method that may allow to distinguish ductile from brittle fractures of metals - as material defects are one of the potential causes of such accidents. Currently, the gold standard in material studies is represented by scanning electron microscopy (SEM). However, SEM are large, lab-based systems, therefore in situ measurements are excluded. In addition, they are expensive and time-consuming. We have approached this problem and propose the use of Optical Coherence Tomography (OCT) in such investigations in order to overcome these disadvantages of SEM. In this respect, we demonstrate the capability to perform such fracture analysis by obtaining the topography of metallic surfaces using OCT. Different materials have been analyzed; in this presentation a sample of low soft carbon steel with the chemical composition of C 0.2%, Mn 1.15%, S 0.04%, P 0.05 % and Fe for the rest has been considered. An in-house developed Swept Source (SS) OCT system has been used, and height profiles have been generated for the sample surface. This profile allowed for concluding that the carbon steel sample was subjected to a ductile fracture. A validation of the OCT images obtained with a 10 microns resolution has been made with SEM images obtained with a 4 nm resolution. Although the OCT resolution is much lower than the one of SEM, we thus demonstrate that it is sufficient in order to obtain clear images of the grains of the metallic materials and thus to distinguish between ductile and brittle fractures. This study analysis opens avenues for a range of applications, including: (i) to determine the causes that have generated pipe ruptures, or structural failures of metallic bridges and buildings, as well as damages of machinery parts; (ii) to optimize the design of various machinery; (iii) to obtain data regarding the structure of metallic alloys); (iv) to improve the manufacturing technologies of metallic parts.

4D ERT Monitoring of Subsurface Water Pipe Leakage During a Controlled Field Experiment

NASA Astrophysics Data System (ADS)

Inauen, C.; Chambers, J. E.; Wilkinson, P. B.; Meldrum, P.; Swift, R. T.; Uhlemann, S.; Gunn, D.; Dashwood, B.; Taxil, J.; Curioni, G.

2016-12-01

Locating and delineating leakage from subsurface pipelines is an important task for civil engineers. 4D Electrical Resistivity Tomography (ERT) allows changes in subsurface resistivity to be imaged at a high spatial and temporal resolution in a minimally invasive manner. It is therefore a promising tool to supplement conventional point-sensing techniques to monitor subsurface flow processes. To assess the efficacy of ERT for pipe leakage monitoring several controlled leak experiments were carried out at a test site in Blagdon, Bristol, UK. To simulate the leak, a plastic pipe with a hole was buried below a flat, grassed area at a depth of 0.7 m, representing a standard UK mains water pipe installation. The water table at the site lies well below the surface meaning that the experiment took entirely place in the vadose zone, where changes in resistivity are primarily sensitive to water content variations. The ERT array covered an area of 6.5m x 6.5m around the leak location. Data acquisition was carried out with the BGS PRIME (Proactive Infrastructure Monitoring and Evaluation) system, which facilitates remote scheduling and autonomous ERT data collection and transmission. To obtain the resistivity changes of the subsurface a 4D inversion was carried out using a Gauss-Newton approach with spatial and temporal smoothness constraints. We were able to reliably observe the onset, spread and cessation of the leakage. Measurements from in-situ soil sensors at several depths above and below the leak complemented the ERT data and allowed us to assess their reliability and directly relate them to hydrogeological processes. Moreover, through experimental tests with soil samples from the test area, a Waxman-Smits relation was obtained to directly convert the changes in electrical resistivity to gravimetric soil moisture content. With future experiments on the test site more work is planned towards survey optimization, automated processing and tracking of leakage plumes.

Hydraulic-fracture diagnostic research. Final report, December 1989-December 1990

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fix, J.E.; Adair, R.G.; Clawson, G.E.

1992-05-01

The results of the research in microseismic methods to determine hydraulic fracture dimensions during the contract were significant. The GRI Hydraulic Fracture Test Site (HFTS) development planning was a major effort. Ten meetings of the Planning Team were coordinated and hosted. A statement of the HFTS mission, scope, objectives, and requirements was created. The primary objectives were to provide for interdisciplinary experiments on fracture modeling and fracture diagnostics. A Conceptual Plan for the HFTS was compiled by Teledyne Geotech and distributed at the Project Advisors Group meeting. An experiment at the Shell South Belridge Field in California was a directmore » analog of the HFTS. Multiple fracture stimulations were monitored from 3 wells with cemented-in geophones. Methods of handling and processing large data volumes in real time were established. The final fracture geometry did not fit the circular model. Fracture diagnostics were monitored at two GRI cooperative wells: the Enron S. Hogsback No. 13-8A and the Phillips Ward C No. 11. Theoretical studies indicate that crack waves might be used as an estimate of fracture length. After applying advanced signal enhancement techniques to low-frequency signals from 14 surveys, it was concluded that the data from presently available sondes is contaminated by sonde resonances.« less

Fracture in Westerly granite under AE feedback and constant strain rate loading: Nucleation, quasi-static propagation, and the transition to unstable fracture propagation

USGS Publications Warehouse

Thompson, B.D.; Young, R.P.; Lockner, D.A.

2006-01-01

New observations of fracture nucleation are presented from three triaxial compression experiments on intact samples of Westerly granite, using Acoustic Emission (AE) monitoring. By conducting the tests under different loading conditions, the fracture process is demonstrated for quasi-static fracture (under AE Feedback load), a slowly developing unstable fracture (loaded at a 'slow' constant strain rate of 2.5 ?? 10-6/s) and an unstable fracture that develops near instantaneously (loaded at a 'fast' constant strain rate of 5 ?? 10-5/s). By recording a continuous ultrasonic waveform during the critical period of fracture, the entire AE catalogue can be captured and the exact time of fracture defined. Under constant strain loading, three stages are observed: (1) An initial nucleation or stable growth phase at a rate of ??? 1.3 mm/s, (2) a sudden increase to a constant or slowly accelerating propagation speed of ??? 18 mm/s, and (3) unstable, accelerating propagation. In the ??? 100 ms before rupture, the high level of AE activity (as seen on the continuous record) prevented the location of discrete AE events. A lower bound estimate of the average propagation velocity (using the time-to-rupture and the existing fracture length) suggests values of a few m/s. However from a low gain acoustic record, we infer that in the final few ms, the fracture propagation speed increased to 175 m/s. These results demonstrate similarities between fracture nucleation in intact rock and the nucleation of dynamic instabilities in stick slip experiments. It is suggested that the ability to constrain the size of an evolving fracture provides a crucial tool in further understanding the controls on fracture nucleation. ?? Birkha??user Verlag, Basel, 2006.

Butt Welding of 2205/X65 Bimetallic Sheet and Study on the Inhomogeneity of the Properties of the Welded Joint

NASA Astrophysics Data System (ADS)

Gou, Ning-Nian; Zhang, Jian-Xun; Wang, Jian-Long; Bi, Zong-Yue

2017-04-01

The explosively welded 2205 duplex stainless steel/X65 pipe steel bimetallic sheets were butt jointed by multilayer and multi-pass welding (gas tungsten arc welding for the flyer and gas metal arc welding for the transition and parent layers of the bimetallic sheets). The microstructure and mechanical properties of the welded joint were investigated. The results showed that in the thickness direction, microstructure and mechanical properties of the welded joint exhibited obvious inhomogeneity. The microstructures of parent filler layers consisted of acicular ferrite, widmanstatten ferrite, and a small amount of blocky ferrite. The microstructure of the transition layer and flyer layer consisted of both austenite and ferrite structures; however, the transition layer of weld had a higher volume fraction of austenite. The results of the microhardness test showed that in both weld metal (WM) and heat-affected zone (HAZ) of the parent filler layers, the average hardness decreased with the increasing (from parent filler layer 1 to parent filler layer 3) welding heat input. The results of hardness test also indicated that the hardness of the WM and the HAZ for the flyer and transition layers was equivalent. The tensile test combined with Digital Specklegram Processing Technology demonstrated that the fracturing of the welded joint started at the HAZ of the flyer, and then the fracture grew toward the base metal of the parent flyer near the parent HAZ. The stratified impact test at -5 °C showed that the WM and HAZ of the flyer exhibited lower impact toughness, and the fracture mode was ductile and brittle mixed fracture.

Heterogeneous flow in multi-layer joint networks and its influence on incipient karst generation

NASA Astrophysics Data System (ADS)

Wang, X.; Jourde, H.

2017-12-01

Various dissolution types (e.g. pipe, stripe and sheet karstic features) have been observed in fractured layered limestones. Yet, due to a large range of structural and hydraulic parameters play a role in the karstification process, the dissolution mechanism, occurring either along fractures or bedding planes, is difficult to quantify. In this study, we use numerical models to investigate the influence of these parameters on the generation of different types of incipient karst. Specifically, we focus on two parameters: the fracture intensity contrast between adjacent layers and the aperture ratio between bedding planes and joints (abed/ajoint). The DFN models were generated using a pseudo-genetic code that considers the stress shadow zone. Flow simulations were performed using a combined finite-volume finite-element simulator under practical boundary conditions. The flow channeling within the fracture networks was characterized by applying a multi-fractal technique. The rock block equivalent permeability (keff) was also calculated to quantify the change in bulk hydraulic properties when changing the selected structural and hydraulic parameters. The flow simulation results show that the abed/ajoint ratio has a first-order control on the heterogeneous distribution of flow in the multi-layer system and on the magnitude of equivalent permeability. When abed/ajoint < 0.1, flow in the system is highly localized and controlled by joints, and the keff is low; while, when abed/ajoint > 0.1, the bedding plane has more control and flow becomes more pervasive and uniform, and the keff is accordingly high. A simple model, accounting for the calculation of the heterogeneous distributions of Damköhler number associated with different aperture ratios, is proposed to predict what type of incipient karst tends to develop under the studied flow conditions.

The stability of a hip fracture determines the fatigue of an intramedullary nail.

PubMed

Eberle, S; Bauer, C; Gerber, C; von Oldenburg, G; Augat, P

2010-01-01

The purpose of this study was to address the question of how the stability of a proximal hip fracture determines the fatigue and failure mechanism of an intramedullary implant. To answer this question, mechanical experiments and finite element simulations with two different loading scenarios were conducted. The two load scenarios differed in the mechanical support of the fracture by an artificial bone sleeve, representing the femoral head and neck. The experiments confirmed that an intramedullary nail fails at a lower load in an unstable fracture situation in the proximal femur than in a stable fracture. The nails with an unstable support failed at a load 28 per cent lower than the nails with a stable support by the femoral neck. Hence, the mechanical support of a fracture is crucial to the fatigue failure of an implant. The simulation showed why the fatigue fracture of the nail starts at the aperture of the lag screw. It is the location of the highest von Mises stress, which is the failure criterion for ductile materials.

Active and passive seismic imaging of a hydraulic fracture in diatomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinegar, H.J.; Wills, P.B.; De Martini, D.C.

1992-01-01

This paper reports on a comprehensive set of experiments including remote- and treatment-well microseismic monitoring, interwell shear-wave shadowing, and surface tiltmeter arrays, that was used to monitor the growth of a hydraulic fracture in the Belridge diatomite. To obtain accurate measurements, and extensive subsurface network of geophones was cemented spanning the diatomite formation in three closely spaced observation wells around the well to be fracture treated. Data analysis indicates that the minifracture and main hydraulic fracture stimulations resulted in a nearly vertical fracture zone (striking N26{degrees}E) vertically segregated into two separate elements, the uppermost of which grew 60 ft abovemore » the perforated interval. The interwell seismic effects are consistent with a side process zone of reduced shear velocity, which remote-well microseismic data independently suggest may be as wide as 40 ft. The experiments indicate complicated processes occurring during hydraulic fracturing that have significant implications for stimulation, waterflooding, in fill drilling, and EOR. These processes are neither well understood nor included in current hydraulic fracture models.« less

Numerical Experiments on Ductile Fracture in Granites

NASA Astrophysics Data System (ADS)

Regenauer-Lieb, K.; Weinberg, R. F.

2006-12-01

Ceramics and, by analogy rocks, are brittle at low temperatures, however, at high temperature and high pressure a second ductile mode of fracture based on dislocation and/or diffusion processes predominates. For ceramics 0.5-0.7 times the melting temperature suffice to create creep/ductile fracture which occurs typically after long time of deformation 104-1010 s (1). Ductile creep fractures make up for the low stress by profiting from accumulated strain and diffusion during slow creep deformation. Creep fractures typically nucleate on grain or phase boundaries, rigid or soft inclusions. Ultimately, the localized inhomogeneous damaged zone, begin to spread laterally and coalesce to create or follow a propagating shear band. The creep fracture sequence of crack nucleation, growth and coalescence relies on a mechanism of self-organization of fluids into a shear band during deformation and converts macroscopically to the crack like propagation of localized shear zones. Numerical experiments are used to test the ductile fracture hypothesis for the segregation and transfer of melts in granites. Ref: (1) C. Ghandi, M. F. Ashby, Acta Metallurgica 27, 1565 (1979).

Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005

USGS Publications Warehouse

Shoemaker, W. Barclay; Kuniansky, Eve L.; Birk, Steffen; Bauer, Sebastian; Swain, Eric D.

2007-01-01

This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by modifying horizontal conductances assembled by the Block-Centered Flow (BCF), Layer-Property Flow (LPF), or Hydrogeologic-Unit Flow Packages (HUF) of MODFLOW-2005. For both conduit flow pipes (CFPM1) and preferential flow layers (CFPM2), critical Reynolds numbers are used to determine if flow is laminar or turbulent. Due to conservation of momentum, flow in a laminar state tends to remain laminar and flow in a turbulent state tends to remain turbulent. This delayed transition between laminar and turbulent flow is introduced in the CFP, which provides an additional benefit of facilitating convergence of the computer algorithm during iterations of transient simulations. Specifically, the user can specify a higher critical Reynolds number to determine when laminar flow within a pipe converts to turbulent flow, and a lower critical Reynolds number for determining when a pipe with turbulent flow switches to laminar flow. With CFPM1, the Hagen-Poiseuille equation is used for laminar flow conditions and the Darcy-Weisbach equation is applied to turbulent flow conditions. With CFPM2, turbulent flow is approximated by reducing the laminar hydraulic conductivity by a nonlinear function of the Reynolds number, once the critical head difference is exceeded. This adjustment approximates the reductions in mean velocity under turbulent ground-water flow conditions.

Experimental and theoretical fracture mechanics applied to volcanic conduits and domes

NASA Astrophysics Data System (ADS)

Sammonds, P.; Matthews, C.; Kilburn, C.; Smith, R.; Tuffen, H.; Meredith, P.

2008-12-01

We present an integrated modelling and experimental approach to magma deformation and fracture, which we attempt to validate against field observations of seismicity. The importance of fracture processes in magma ascent dynamics and lava dome growth and collapse are apparent from the associated seismicity. Our laboratory experiments have shown that brittle fracture of magma can occur at high temperature and stress conditions prevalent in the shallow volcanic system. Here, we use a fracture mechanics approach to model seismicity preceding volcanic eruptions. Starting with the fracture mechanics concept of a crack in an elastic body, we model crack growth around the volcanic conduit through the processes of crack interactions, leading either to the propagation and linkage of cracks, or crack avoidance and the inhibition of crack propagation. The nature of that interaction is governed by the temperature and plasticity of the magma. We find that fracture mechanics rules can account for the style of seismicity preceding eruptions. We have derived the changes in seismic b-value predicted by the model and interpret these in terms of the style of fracturing, fluid flow and heat transport. We compare our model with results from our laboratory experiments where we have deformed lava at high temperatures under triaxial stresses. These experiments were conducted in dry and water saturated conditions at effective pressures up to 10 MPa, temperatures up to 1000°C and strain rates from 10-4 s-1 to 10-6 s-1. The behaviour of these magmas was largely brittle under these conditions. We monitored the acoustic emission emitted and calculate the change in micro-seismic b-value with deformation. These we find are in accord with volcano seismicity and our fracture mechanics model.

Life impact of ankle fractures: qualitative analysis of patient and clinician experiences.

PubMed

McPhail, Steven M; Dunstan, Joel; Canning, Julie; Haines, Terry P

2012-11-21

Ankle fractures are one of the more commonly occurring forms of trauma managed by orthopaedic teams worldwide. The impacts of these injuries are not restricted to pain and disability caused at the time of the incident, but may also result in long term physical, psychological, and social consequences. There are currently no ankle fracture specific patient-reported outcome measures with a robust content foundation. This investigation aimed to develop a thematic conceptual framework of life impacts following ankle fracture from the experiences of people who have suffered ankle fractures as well as the health professionals who treat them. A qualitative investigation was undertaken using in-depth semi-structured interviews with people (n=12) who had previously sustained an ankle fracture (patients) and health professionals (n=6) that treat people with ankle fractures. Interviews were audio-recorded and transcribed. Each phrase was individually coded and grouped in categories and aligned under emerging themes by two independent researchers. Saturation occurred after 10 in-depth patient interviews. Time since injury for patients ranged from 6 weeks to more than 2 years. Experience of health professionals ranged from 1 year to 16 years working with people with ankle fractures. Health professionals included an Orthopaedic surgeon (1), physiotherapists (3), a podiatrist (1) and an occupational therapist (1). The emerging framework derived from patient data included eight themes (Physical, Psychological, Daily Living, Social, Occupational and Domestic, Financial, Aesthetic and Medication Taking). Health professional responses did not reveal any additional themes, but tended to focus on physical and occupational themes. The nature of life impact following ankle fractures can extend beyond short term pain and discomfort into many areas of life. The findings from this research have provided an empirically derived framework from which a condition-specific patient-reported outcome measure can be developed.

2017 GTO Project review Laboratory Evaluation of EGS Shear Stimulation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Stephen J.

The objectives and purpose of this research has been to produce laboratory-based experimental and numerical analyses to provide a physics-based understanding of shear stimulation phenomena (hydroshearing) and its evolution during stimulation. Water was flowed along fractures in hot and stressed fractured rock, to promote slip. The controlled laboratory experiments provide a high resolution/high quality data resource for evaluation of analysis methods developed by DOE to assess EGS “behavior” during this stimulation process. Segments of the experimental program will provide data sets for model input parameters, i.e., material properties, and other segments of the experimental program will represent small scale physicalmore » models of an EGS system, which may be modeled. The coupled lab/analysis project has been a study of the response of a fracture in hot, water-saturated fractured rock to shear stress experiencing fluid flow. Under this condition, the fracture experiences a combination of potential pore pressure changes and fracture surface cooling, resulting in slip along the fracture. The laboratory work provides a means to assess the role of “hydroshearing” on permeability enhancement in reservoir stimulation. Using the laboratory experiments and results to define boundary and input/output conditions of pore pressure, thermal stress, fracture shear deformation and fluid flow, and models were developed and simulations completed by the University of Oklahoma team. The analysis methods are ones used on field scale problems. The sophisticated numerical models developed contain parameters present in the field. The analysis results provide insight into the role of fracture slip on permeability enhancement-“hydroshear” is to be obtained. The work will provide valuable input data to evaluate stimulation models, thus helping design effective EGS.« less

Adaptive and Collaborative Exploitation of 3 Dimensional Environmental Acoustics in Distributed Undersea Networks

DTIC Science & Technology

2015-09-30

experiment was conducted in Broad Sound of Massachusetts Bay using the AUV Unicorn, a 147dB omnidirectional Lubell source, and an open-ended steel pipe... steel pipe target (Figure C) was dropped at an approximate local coordinate position of (x,y)=(170,155). The location was estimated using ship...position when the target was dropped, but was only accurate within 10-15m. The orientation of the target was unknown. Figure C: Open-ended steel

Hydraulic Design of Navigation Locks

DTIC Science & Technology

1989-09-01

service brought about by surface deposits, erossion, corrosion , bacterial slimes and growths and marine and fresh water fouling. Experience of similar...Drawn brass, copper, alluminium , etc. 0.0025 Glass, plastic, perspex, fibre glass, etc. 0.0025 2. Steel pipes New smooth pipes 0.025 Centrifugally...1 H l I T j I 1 1 In E 1- 0 C D I ) N N C4dv Fig. .1. oodyChar TBT7 2. Adequate initial protection to prevent corrosion and erosion. 3. Chlorination

Gas distribution equipment in hydrogen service - Phase II

NASA Technical Reports Server (NTRS)

Jasionowski, W. J.; Huang, H. D.

1980-01-01

The hydrogen permeability of three different types of commercially available natural gas polyethylene pipes was determined. Ring tensile tests were conducted on permeability-exposed and as-received samples. Hydrogen-methane leakage experiments were also performed. The results show no selective leakage of hydrogen via Poiseuille, turbulent, or orifice flow (through leaks) on the distribution of blends of hydrogen and methane. The data collected show that the polyethylene pipe is 4 to 6 times more permeable to hydrogen than to methane.

ADDITIONAL STRESS AND FRACTURE MECHANICS ANALYSES OF PRESSURIZED WATER REACTOR PRESSURE VESSEL NOZZLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, Matthew; Yin, Shengjun; Stevens, Gary

2012-01-01

In past years, the authors have undertaken various studies of nozzles in both boiling water reactors (BWRs) and pressurized water reactors (PWRs) located in the reactor pressure vessel (RPV) adjacent to the core beltline region. Those studies described stress and fracture mechanics analyses performed to assess various RPV nozzle geometries, which were selected based on their proximity to the core beltline region, i.e., those nozzle configurations that are located close enough to the core region such that they may receive sufficient fluence prior to end-of-life (EOL) to require evaluation of embrittlement as part of the RPV analyses associated with pressure-temperaturemore » (P-T) limits. In this paper, additional stress and fracture analyses are summarized that were performed for additional PWR nozzles with the following objectives: To expand the population of PWR nozzle configurations evaluated, which was limited in the previous work to just two nozzles (one inlet and one outlet nozzle). To model and understand differences in stress results obtained for an internal pressure load case using a two-dimensional (2-D) axi-symmetric finite element model (FEM) vs. a three-dimensional (3-D) FEM for these PWR nozzles. In particular, the ovalization (stress concentration) effect of two intersecting cylinders, which is typical of RPV nozzle configurations, was investigated. To investigate the applicability of previously recommended linear elastic fracture mechanics (LEFM) hand solutions for calculating the Mode I stress intensity factor for a postulated nozzle corner crack for pressure loading for these PWR nozzles. These analyses were performed to further expand earlier work completed to support potential revision and refinement of Title 10 to the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G, Fracture Toughness Requirements, and are intended to supplement similar evaluation of nozzles presented at the 2008, 2009, and 2011 Pressure Vessels and Piping (PVP) Conferences. This work is also relevant to the ongoing efforts of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code, Section XI, Working Group on Operating Plant Criteria (WGOPC) efforts to incorporate nozzle fracture mechanics solutions into a revision to ASME B&PV Code, Section XI, Nonmandatory Appendix G.« less

[Eponyms of distal radius fractures. Colles-Pouteau, Smith-Goyrand and Barton fractures and their importance in the trauma surgery patient sample].

PubMed

Ebert, B; Müller, J E

1993-10-01

Fractures at the distal end of the radius are quite common. So, these fractures are well known to represent consequences of industrial accidents leading to temporary unfitness for work, too. Eponym descriptions of fractures may mislead authors and readers as well if used in a non-uniform way in medical literature. Using the original articles of the first describing authors a clear distinction of eponyms concerning fractures near to the wrist joint is given. The authors of this feature report of the clinical experience in treatment and results of distal radius fractures in combination with aspects of expert opinions on these fractures.

Structures Formed in Experimentally Sheared Artificial Fault Gouge: Precise Statistical Measurements

NASA Astrophysics Data System (ADS)

Dilov, T.; Yoshida, S.; Kato, A.; Nakatani, M.; Mochizuki, H.; Otsuki, K.

2004-12-01

The physical parameters governing earthquakes change with the ongoing formation and evolution of structures, formed in the course of a single or multiple earthquakes, within a particular fault zone or in a broad volume containing interacting tectonic faults. Our precise knowledge of these complex phenomena is still elusive. Especially, works considering geometrical evolution of shear structures under controlled conditions are rare. In order to gain some insights we accomplished a set of 12 laboratory experiments using a servo-controlled direct-shear apparatus, under room temperature and without controlling the air humidity. Two fault gouge layers (industrially produced quartz powder, average particle size of 5 μ m, and pre-shear thickness of 1.5, 2.0 and 3.0 mm,) were sandwiched between three granite blocks. The middle block was slid in order to create frictional structures within the simulated gouge. The total imposed shear strain varies between 0.14 and 11.80. The post-shear gouge layer thickness ranges from 0.99-2.11 mm. Each experiment was run under a constant normal stress (varying from 10-44 MPa through the experiments) and at a constant shear velocity (0.07, 0.7 and 7 μ m/s, through the experiments). Later, in cross-sections of solidified by epoxy glue gouge (parallel to the shear direction, normal to the gouge walls,) we quantified the numerous R-shears, according to their density distribution, fracture thickness (measured perpendicularly to the fracture walls), fracture angle and morphology, and fracture length. In gouge views parallel to the sliding blocks, we measured fracture length and along-strike R-shear morphology. Although the latter data are with lower quality, both observational sets provide precise statistical fracture data as well snapshots of evolving 3D structures. We observe shear localization with decreasing gouge layer thickness and with increasing normal stress. The average density of major fractures increases from 2.83 to 3.67 [fracture/cm] for decrease of the post-shear gouge layer thickness. This is at the expense of a considerable decrease of visible more diffusive minor fractures. On the other hand, the fractures formed at lower normal stress are more irregular and show average fracture density of 4.48 [fracture/cm]. The latter decreases down to 3.64 at higher normal stress, as the fracture morphology becomes more regular. The fracture density increases abruptly from zero, after a small total shear strain (0.15-0.50), and later the change is slower or none with the increase of the total shear strain; the fractures are already localized and they accommodate most of the brittle deformation. Also we observe weak polarity in fracture development in accordance to the sliding sense, especially in the subset of fractures starting from the gouge wall and dying out within the gouge layer. More such fractures are developed along the leading part of the sliding blocks. Our results throw new light over the formation and development of fault-related structures and their dependency on the earthquake-governing physical parameters.

Fluid-driven Fractures and Backflow in a Multilayered Elastic Matrix

NASA Astrophysics Data System (ADS)

Smiddy, Samuel; Lai, Ching-Yao; Stone, Howard

2016-11-01

We study the dynamics when pressurized fluid is injected at a constant flow rate into a multi-layered elastic matrix. In particular, we report experiments of such crack propagation as a function of orientation and distance from the contact of the layers. Subsequently we study the shape and propagation of the fluid along the contact of layers as well as volume of fluid remaining in the matrix once the injection pressure is released and "flowback" occurs. The experiments presented here may mimic the interaction between hydraulic fractures and pre-existing fractures and the dynamics of flowback in hydraulic fracturing. Study made possible by the Andlinger Center for Energy and the Environment and the Fred Fox Fund.

Fracture propagation during fluid injection experiments in shale at elevated confining pressures.

NASA Astrophysics Data System (ADS)

Chandler, Mike; Mecklenburgh, Julian; Rutter, Ernest; Fauchille, Anne-Laure; Taylor, Rochelle; Lee, Peter

2017-04-01

The use of hydraulic fracturing to recover shale-gas has focused attention upon the fundamental fracture properties of gas-bearing shales. Fracture propagation trajectories in these materials depend on the interaction between the anisotropic mechanical properties of the shale and the anisotropic in-situ stress field. However, there is a general paucity of available experimental data on their anisotropic mechanical, physical and fluid-flow properties, especially at elevated confining pressures. Here we report the results of laboratory-scale fluid injection experiments, for Whitby mudstone and Mancos shale (an interbedded silt and mudstone), as well as Pennant sandstone (a tight sandstone with permeability similar to shales), which is used an isotropic baseline and tight-gas sandstone analogue. Our injection experiments involved the pressurisation of a blind-ending central hole in an initially dry cylindrical sample. Pressurisation was conducted under constant volume-rate control, using silicone oils of various viscosities. The dependence of breakdown pressure on confining pressure was seen to be dependent on the rock strength, with the significantly stronger Pennant sandstone exhibiting much lower confining-pressure dependence of breakdown pressure than the weaker shales. In most experiments, a small drop in the injection pressure record was observed at what is taken to be fracture initiation, and in the Pennant sandstone this was accompanied by a small burst of acoustic energy. Breakdown was found to be rapid and uncontrollable after initiation if injection is continued, but can be limited to a slower (but still uncontrolled) rate by ceasing the injection of fluid after the breakdown initiation in experiments where it could be identified. A simplified 2-dimensional model for explaining these observations is presented in terms of the stress intensities at the tip of a pressurised crack. Additionally, we present a suite of supporting mechanical, flow and elastic measurements. Mechanical experiments include standard triaxial tests, pressure-dependent permeability experiments and fracture toughness determined using the double-torsion test. Elastic characterisation was determined through ultrasonic velocities determined using a cross-correlation method.

Experimental and Numerical Investigations on Colloid-facilitated Plutonium Reactive Transport in Fractured Tuffaceous Rocks

NASA Astrophysics Data System (ADS)

Dai, Z.; Wolfsberg, A. V.; Zhu, L.; Reimus, P. W.

2017-12-01

Colloids have the potential to enhance mobility of strongly sorbing radionuclide contaminants in fractured rocks at underground nuclear test sites. This study presents an experimental and numerical investigation of colloid-facilitated plutonium reactive transport in fractured porous media for identifying plutonium sorption/filtration processes. The transport parameters for dispersion, diffusion, sorption, and filtration are estimated with inverse modeling for minimizing the least squares objective function of multicomponent concentration data from multiple transport experiments with the Shuffled Complex Evolution Metropolis (SCEM). Capitalizing on an unplanned experimental artifact that led to colloid formation and migration, we adopt a stepwise strategy to first interpret the data from each experiment separately and then to incorporate multiple experiments simultaneously to identify a suite of plutonium-colloid transport processes. Nonequilibrium or kinetic attachment and detachment of plutonium-colloid in fractures was clearly demonstrated and captured in the inverted modeling parameters along with estimates of the source plutonium fraction that formed plutonium-colloids. The results from this study provide valuable insights for understanding the transport mechanisms and environmental impacts of plutonium in fractured formations and groundwater aquifers.

Solute transport along preferential flow paths in unsaturated fractures

USGS Publications Warehouse

Su, Grace W.; Geller, Jil T.; Pruess, Karsten; Hunt, James R.

2001-01-01

Laboratory experiments were conducted to study solute transport along preferential flow paths in unsaturated, inclined fractures. Qualitative aspects of solute transport were identified in a miscible dye tracer experiment conducted in a transparent replica of a natural granite fracture. Additional experiments were conducted to measure the breakthrough curves of a conservative tracer introduced into an established preferential flow path in two different fracture replicas and a rock‐replica combination. The influence of gravity was investigated by varying fracture inclination. The relationship between the travel times of the solute and the relative influence of gravity was substantially affected by two modes of intermittent flow that occurred: the snapping rivulet and the pulsating blob modes. The measured travel times of the solute were evaluated with three transfer function models: the axial dispersion, the reactors‐in‐series, and the lognormal models. The three models described the solute travel times nearly equally well. A mechanistic model was also formulated to describe transport when the pulsating blob mode occurred which assumed blobs of water containing solute mixed with residual pools of water along the flow path.

Shake, Rupture And Flow: Hydraulic Constraints On The Formation Of Europa’s Chaos

NASA Astrophysics Data System (ADS)

Schmidt, Britney E.; Gooch, B. T.; Blankenship, D. D.; Soderlund, K. M.

2012-10-01

Europa’s chaos terrains may have formed above shallow water lenses formed by melting of the upper ice shell with ascending thermo-compositional plumes. A key factor in the creation of chaos terrain may be dramatic disruption and collapse of the ice lid above the forming melt lens along with potentially violent mixing upon its rupture; this is analogous to the collapse of terrestrial ice shelves in which massive ice bodies disintegrate in a few days. At Thera Macula, there is evidence for modification by water immediately external to the scarp that bounds the collapsed region. Since water runs either subaerially down hill or from high pressure to low when below or within ice, the swollen appearance of bands entering Thera Macula, which are uphill in terms of hydraulic and topographic gradients, raises the possibility that this steep scarp represents the place where the lens initially broke. As the ice lid ruptures, the overpressure within the lens may create sufficient pressure within the fracture to drive water through it, allowing water to escape into and modify surrounding terrain. Similar effects are seen when aquifers or subglacial water sources are tapped: water flows up the pipe until the pressure in the water body is relieved and the hydraulic “pressure head” in the pipe is lowered. We have modeled the hydraulic potential associated with a rupturing lens in order to investigate the range of parameters for overpressure, fracture width, and lid thickness that could produce such modification as is observed at Thera Macula. These place important constraints on the pressure within the lens and the energetics of a collapse event. These estimates may explain how ice masses within chaos are initially disrupted and provide a means for quantifying the vigor of surface-subsurface mixing that could be critical to Europa’s habitability.

Core Flooding Experiments Combined with X-rays and Micro-PET Imaging as a Tool to Calculate Fluid Saturations in a Fracture

NASA Astrophysics Data System (ADS)

Gran, M.; Zahasky, C.; Garing, C.; Pollyea, R. M.; Benson, S. M.

2017-12-01

One way to reduce CO2 emissions is to capture CO2 generated in power plants and other industrial sources to inject it into a geological formation. Sedimentary basins are the ones traditionally used to store CO2 but the emission sources are not always close to these type of basins. In this case, basalt rocks present a good storage alternative due their extent and also their potential for mineral trapping. Flow through basaltic rocks is governed by the permeable paths provided by rock fractures. Hence, knowing the behavior of the multiphase flow in these fractures becomes crucial. With the aim to describe how aperture and liquid-gas interface changes in the fracture affect relative permeability and what are the implications of permeability stress dependency, a series of core experiments were conducted. To calculate fracture apertures and fluid saturations, core flooding experiments combined with medical X-Ray CT scanner and micro-PET imaging (Micro Positron Emission Tomography) were performed. Capillary pressure and relative permeability drainage curves were simultaneously measured in a fractured basalt core under typical storage reservoir pressures and temperatures. The X-Ray scanner allows fracture apertures to be measured quite accurately even for fractures as small as 30 µ, but obtaining fluid saturations is not straightforward. The micro-PET imaging provides dynamic measurements of tracer distributions which can be used to calculate saturation. Here new experimental data is presented and the challenges associated with measuring fluid saturations using both X-Rays and micro-PET are discussed.

Modular Cooling Components

NASA Technical Reports Server (NTRS)

Eastman, G. Yale; Dussinger, Peter M.; Hartenstine, John R.

1994-01-01

Three modular heat-transfer components designed for use together or separately. Simple mechanical connections facilitate assembly of these and related heat-transfer components into cooling systems of various configurations, such as to cool laboratory equipment rearranged for different experiments. Components are clamp-on cold plate, cold plate attached to flexible heat pipe, and thermal-bus receptacle. Clamp-on cold plate moved to any convenient location for attachment of equipment cooled by it, then clamped onto thermal bus. Heat from equipment conducted through plate and into coolant. Thermal-bus receptacle integral with thermal bus. Includes part of thermal bus to which clamp-on cold plate attached, plus tapered socket into which condenser end of flexible heat pipe plugged. Thermal-bus receptacle includes heat-pipe wick structure using coolant in bus to enhance transfer of heat from cold plate.

Effect of Water Cut on Pressure Drop of Oil (D130) -Water Flow in 4″Horizontal Pipe

NASA Astrophysics Data System (ADS)

Basha, Mehaboob; Shaahid, S. M.; Al-Hems, Luai M.

2018-03-01

The oil-water flow in pipes is a challenging subject that is rich in physics and practical applications. It is often encountered in many oil and chemical industries. The pressure gradient of two phase flow is still subject of immense research. The present study reports pressure measurements of oil (D130)-water flow in a horizontal 4″ diameter stainless steel pipe at different flow conditions. Experiments were carried out for different water cuts (WC); 0-100%. Inlet oil-water flow rates were varied from 4000 to 8000 barrels-per-day in steps of 2000. It has been found that the frictional pressure drop decreases for WC = 0 - 40 %. With further increase in WC, friction pressure drop increases, this could be due to phase inversion.

A new mechanism for periodic bursting of the recirculation region in the flow through a sudden expansion in a circular pipe

NASA Astrophysics Data System (ADS)

Lebon, Benoit; Nguyen, Minh Quan; Peixinho, Jorge; Shadloo, Mostafa Safdari; Hadjadj, Abdellah

2018-03-01

We report the results of a combined experimental and numerical study of specific finite-amplitude disturbances for transition to turbulence in the flow through a circular pipe with a sudden expansion. The critical amplitude thresholds for localized turbulent patch downstream of the expansion scale with the Reynolds number with a power law exponent of -2.3 for experiments and -2.8 for simulations. A new mechanism for the periodic bursting of the recirculation region is uncovered where the asymmetric recirculation flow develops a periodic dynamics: a secondary recirculation breaks the symmetry along the pipe wall and bursts into localized turbulence, which travels downstream and relaminarises. Flow visualizations show a simple flow pattern of three waves forming, growing, and bursting.

Unsteady heat transfer performance of heat pipe with axially swallow-tailed microgrooves

NASA Astrophysics Data System (ADS)

Zhang, R. P.

2017-04-01

A mathematical model is developed for predicting the transient heat transfer and fluid flow of heat pipe with axially swallow-tailed microgrooves. The effects of liquid convective heat transfer in the microgrooves, liquid-vapor interfacial phase-change heat transfer and liquid-vapor interfacial shear stress are accounted for in the present model. The coupled non-linear control equations are solved numerically. Mass flow rate at the interface is obtained from the application of kinetic theory. Time variation of wall temperature is studied from the initial startup to steady state. The numerical results are verified by experiments. Time constants for startup and shutdown operation are defined to determine how fast a heat pipe responds to an applied input heat flux, which slightly decreases with increasing heat load.

Measurements of radiated elastic wave energy from dynamic tensile cracks

NASA Technical Reports Server (NTRS)

Boler, Frances M.

1990-01-01

The role of fracture-velocity, microstructure, and fracture-energy barriers in elastic wave radiation during a dynamic fracture was investigated in experiments in which dynamic tensile cracks of two fracture cofigurations of double cantilever beam geometry were propagating in glass samples. The first, referred to as primary fracture, consisted of fractures of intact glass specimens; the second configuration, referred to as secondary fracture, consisted of a refracture of primary fracture specimens which were rebonded with an intermittent pattern of adhesive to produce variations in fracture surface energy along the crack path. For primary fracture cases, measurable elastic waves were generated in 31 percent of the 16 fracture events observed; the condition for radiation of measurable waves appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For secondary fractures, 100 percent of events showed measurable elastic waves; in these fractures, the ratio of radiated elastic wave energy in the measured component to fracture surface energy was 10 times greater than for primary fracture.

Development of a Novel Synthetic Drug for Osteoporosis and Fracture Healing

DTIC Science & Technology

2015-11-01

Four-point bending setup for mechanical testing. (C & D) X-ray images of the fractured tibiae. Of note, a stainless steel rod was inserted in the...respectively. Figure 15. Mechanical strength 4 weeks after fracture induction for experiment 1. (A) Force- displacement relationship for the hydrogel...University Purdue University Indianapolis, Indianapolis, IN 46202, USA Keywords: bone fracture , tibia, salubrinal, hydrogel, mechanical test Running

Numerical Simulation of Tuff Dissolution and Precipitation Experiments: Validation of Thermal-Hydrologic-Chemical (THC) Coupled-Process Modeling

NASA Astrophysics Data System (ADS)

Dobson, P. F.; Kneafsey, T. J.

2001-12-01

As part of an ongoing effort to evaluate THC effects on flow in fractured media, we performed a laboratory experiment and numerical simulations to investigate mineral dissolution and precipitation. To replicate mineral dissolution by condensate in fractured tuff, deionized water equilibrated with carbon dioxide was flowed for 1,500 hours through crushed Yucca Mountain tuff at 94° C. The reacted water was collected and sampled for major dissolved species, total alkalinity, electrical conductivity, and pH. The resulting steady-state fluid composition had a total dissolved solids content of about 140 mg/L; silica was the dominant dissolved constituent. A portion of the steady-state reacted water was flowed at 10.8 mL/hr into a 31.7-cm tall, 16.2-cm wide vertically oriented planar fracture with a hydraulic aperture of 31 microns in a block of welded Topopah Spring tuff that was maintained at 80° C at the top and 130° C at the bottom. The fracture began to seal within five days. A 1-D plug-flow model using the TOUGHREACT code developed at Berkeley Lab was used to simulate mineral dissolution, and a 2-D model was developed to simulate the flow of mineralized water through a planar fracture, where boiling conditions led to mineral precipitation. Predicted concentrations of the major dissolved constituents for the tuff dissolution were within a factor of 2 of the measured average steady-state compositions. The fracture-plugging simulations result in the precipitation of amorphous silica at the base of the boiling front, leading to a hundred-fold decrease in fracture permeability in less than 6 days, consistent with the laboratory experiment. These results help validate the use of the TOUGHREACT code for THC modeling of the Yucca Mountain system. The experiment and simulations indicate that boiling and concomitant precipitation of amorphous silica could cause significant reductions in fracture porosity and permeability on a local scale. The TOUGHREACT code will be used to evaluate larger-scale silica sealing observed in a portion of the Yellowstone geothermal system, a natural analog for the precipitation-experiment processes.

Vortex breakdown in simple pipe bends

NASA Astrophysics Data System (ADS)

Ault, Jesse; Shin, Sangwoo; Stone, Howard

2016-11-01

Pipe bends and elbows are one of the most common fluid mechanics elements that exists. However, despite their ubiquity and the extensive amount of research related to these common, simple geometries, unexpected complexities still remain. We show that for a range of geometries and flow conditions, these simple flows experience unexpected fluid dynamical bifurcations resembling the bubble-type vortex breakdown phenomenon. Specifically, we show with simulations and experiments that recirculation zones develop within the bends under certain conditions. As a consequence, fluid and particles can remain trapped within these structures for unexpectedly-long time scales. We also present simple techniques to mitigate this recirculation effect which can potentially have impact across industries ranging from biomedical and chemical processing to food and health sciences.

Experimental study of heat transfer enhancement due to the surface vibrations in a flexible double pipe heat exchanger

NASA Astrophysics Data System (ADS)

Hosseinian, A.; Meghdadi Isfahani, A. H.

2018-04-01

In this study, the heat transfer enhancement due to the surface vibration for a double pipe heat exchanger, made of PVDF, is investigated. In order to create forced vibrations (3-9 m/s2, 100 Hz) on the outer surface of the heat exchanger electro-dynamic vibrators are used. Experiments were performed at inner Reynolds numbers ranging from 2533 to 9960. The effects of volume flow rate and temperature on heat transfer performance are evaluated. Results demonstrated that heat transfer coefficient increases by increasing vibration level and mass flow rate. The most increase in heat transfer coefficient is 97% which is obtained for the highest vibration level (9 m/s2) in the experiment range.

Thermal Vacuum Testing of a Multi-Evaporator Miniature Loop Heat Pipe

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Nagano, Hosei

2008-01-01

Under NASA's New Millennium Program Space Technology 8 Project, four experiments are being developed for future small system applications requiring low mass, low power, and compactness. GSFC is responsible for developing the Thermal Loop experiment, which is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and condensers. The objective is to validate the operation of an MLHP, including reliable start-ups, steady operation, heat load sharing, and tight temperature control over the range of 273K to 308K. An MLHP Breadboard has been built and tested for 1200 hours under the laboratory environment and 500 hours in a thermal vacuum chamber. Results of the TV tests are presented here.

Anisotropic nature of radially strained metal tubes

NASA Astrophysics Data System (ADS)

Strickland, Julie N.

Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the strain in the material. The amount of strain is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of strained pipe is desired and valuable. The sponsor currently rates strained pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic strain, which may decrease the yield strength. This study measured the yield strength of strained material in the transverse and axial direction and compared them to raw material, to determine the amount of anisotropy. This information will be used to more accurately determine burst and collapse ratings for strained pipes. More accurate ratings mean safer products, which will minimize risk for the sponsor's customers. Since the strained metal has a higher yield strength than the raw material, using the raw yield strength to calculate burst and collapse ratings is a conservative method. The metal has even higher yield strength after strain aging, which indicates that the stresses are relieved. Even with the 12% anisotropy in the strained and 9% anisotropy in the strain aged specimens, the raw yield strengths are lower and therefore more conservative. I recommend that the sponsor continue using the raw yield strength to calculate these ratings. I set out to characterize the anisotropic nature of swaged metal. As expected, the tensile tests showed a difference between the axial and transverse tensile strength. The correlation was 12% difference in yield strength in the axial and transverse directions for strained material and 9% in strained and aged material. This means that the strength of the metal in the hoop (transverse) direction is approximately 10% stronger than in the axial direction, because the metal was work hardened during the swaging process. Therefore, the metal is more likely to fail in axial tension than in burst or collapse. I presented the findings from the microstructure examination, standard tensile tests, and SEM data. All of this data supported the findings of the mini-tensile tests. This information will help engineers set burst and collapse ratings and allow material scientists to predict the anisotropic characteristics of swaged steel tubes.

Insights about transport mechanisms and fracture flow channeling from multi-scale observations of tracer dispersion in shallow fractured crystalline rock.

PubMed

Guihéneuf, N; Bour, O; Boisson, A; Le Borgne, T; Becker, M W; Nigon, B; Wajiduddin, M; Ahmed, S; Maréchal, J-C

2017-11-01

In fractured media, solute transport is controlled by advection in open and connected fractures and by matrix diffusion that may be enhanced by chemical weathering of the fracture walls. These phenomena may lead to non-Fickian dispersion characterized by early tracer arrival time, late-time tailing on the breakthrough curves and potential scale effect on transport processes. Here we investigate the scale dependency of these processes by analyzing a series of convergent and push-pull tracer experiments with distance of investigation ranging from 4m to 41m in shallow fractured granite. The small and intermediate distances convergent experiments display a non-Fickian tailing, characterized by a -2 power law slope. However, the largest distance experiment does not display a clear power law behavior and indicates possibly two main pathways. The push-pull experiments show breakthrough curve tailing decreases as the volume of investigation increases, with a power law slope ranging from -3 to -2.3 from the smallest to the largest volume. The multipath model developed by Becker and Shapiro (2003) is used here to evaluate the hypothesis of the independence of flow pathways. The multipath model is found to explain the convergent data, when increasing local dispersivity and reducing the number of pathways with distance which suggest a transition from non-Fickian to Fickian transport at fracture scale. However, this model predicts an increase of tailing with push-pull distance, while the experiments show the opposite trend. This inconsistency may suggest the activation of cross channel mass transfer at larger volume of investigation, which leads to non-reversible heterogeneous advection with scale. This transition from independent channels to connected channels when the volume of investigation increases suggest that both convergent and push-pull breakthrough curves can inform the existence of characteristic length scales. Copyright © 2017 Elsevier B.V. All rights reserved.

Insights about transport mechanisms and fracture flow channeling from multi-scale observations of tracer dispersion in shallow fractured crystalline rock

NASA Astrophysics Data System (ADS)

Guihéneuf, N.; Bour, O.; Boisson, A.; Le Borgne, T.; Becker, M. W.; Nigon, B.; Wajiduddin, M.; Ahmed, S.; Maréchal, J.-C.

2017-11-01

In fractured media, solute transport is controlled by advection in open and connected fractures and by matrix diffusion that may be enhanced by chemical weathering of the fracture walls. These phenomena may lead to non-Fickian dispersion characterized by early tracer arrival time, late-time tailing on the breakthrough curves and potential scale effect on transport processes. Here we investigate the scale dependency of these processes by analyzing a series of convergent and push-pull tracer experiments with distance of investigation ranging from 4 m to 41 m in shallow fractured granite. The small and intermediate distances convergent experiments display a non-Fickian tailing, characterized by a -2 power law slope. However, the largest distance experiment does not display a clear power law behavior and indicates possibly two main pathways. The push-pull experiments show breakthrough curve tailing decreases as the volume of investigation increases, with a power law slope ranging from - 3 to - 2.3 from the smallest to the largest volume. The multipath model developed by Becker and Shapiro (2003) is used here to evaluate the hypothesis of the independence of flow pathways. The multipath model is found to explain the convergent data, when increasing local dispersivity and reducing the number of pathways with distance which suggest a transition from non-Fickian to Fickian transport at fracture scale. However, this model predicts an increase of tailing with push-pull distance, while the experiments show the opposite trend. This inconsistency may suggest the activation of cross channel mass transfer at larger volume of investigation, which leads to non-reversible heterogeneous advection with scale. This transition from independent channels to connected channels when the volume of investigation increases suggest that both convergent and push-pull breakthrough curves can inform the existence of characteristic length scales.

Hands-On Exercise in Environmental Structural Geology Using a Fracture Block Model.

ERIC Educational Resources Information Center

Gates, Alexander E.

2001-01-01

Describes the use of a scale analog model of an actual fractured rock reservoir to replace paper copies of fracture maps in the structural geology curriculum. Discusses the merits of the model in enabling students to gain experience performing standard structural analyses. (DDR)

Long-term predictions of minewater geothermal systems heat resources

NASA Astrophysics Data System (ADS)

Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

2014-05-01

Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both through open pipes and from the rock massif) have been implemented. Among others, parametric methods are used to bypass some shortcomings in the physical models used for the subsurface. The advantage is that the complete geometry of the mine workings can be integrated and that computing is fast enough to allow implementing and testing several scenarios (e.g. contributions from fault zones, different assumptions about the actual status of shafts, drifts and mined out areas) in an efficient way (Ferket et al., 2011). EPANET allows to incorporate the full complexity of the subsurface mine structure. As a result, the flooded mine is considered as a network of pipes, each with a custom-defined diameter, length and roughness.

Effect of Aperture Field Variability, Flow Rate, and Ionic Strength on Colloid Transport in Single Fractures: Laboratory-Scale Experiments and Numerical Simulation

NASA Astrophysics Data System (ADS)

Zheng, Q.; Dickson, S.; Guo, Y.

2007-12-01

A good understanding of the physico-chemical processes (i.e., advection, dispersion, attachment/detachment, straining, sedimentation etc.) governing colloid transport in fractured media is imperative in order to develop appropriate bioremediation and/or bioaugmentation strategies for contaminated fractured aquifers, form management plans for groundwater resources to prevent pathogen contamination, and identify suitable radioactive waste disposal sites. However, research in this field is still in its infancy due to the complex heterogeneous nature of fractured media and the resulting difficulty in characterizing this media. The goal of this research is to investigate the effects of aperture field variability, flow rate and ionic strength on colloid transport processes in well characterized single fractures. A combination of laboratory-scale experiments, numerical simulations, and imaging techniques were employed to achieve this goal. Transparent replicas were cast from natural rock fractures, and a light transmission technique was employed to measure their aperture fields directly. The surface properties of the synthetic fractures were characterized by measuring the zeta-potential under different ionic strengths. A 33 (3 increased to the power of 3) factorial experiment was implemented to investigate the influence of aperture field variability, flow rate, and ionic strength on different colloid transport processes in the laboratory-scale fractures, specifically dispersion and attachment/detachment. A fluorescent stain technique was employed to photograph the colloid transport processes, and an analytical solution to the one-dimensional transport equation was fit to the colloid breakthrough curves to calculate the average transport velocity, dispersion coefficient, and attachment/detachment coefficient. The Reynolds equation was solved to obtain the flow field in the measured aperture fields, and the random walk particle tracking technique was employed to model the colloid transport experiments. The images clearly show the development of preferential pathways for colloid transport in the different aperture fields and under different flow conditions. Additionally, a correlation between colloid deposition and fracture wall topography was identified. This presentation will demonstrate (1) differential transport between colloid and solute in single fractures, and the relationship between differential transport and aperture field statistics; (2) the relationship between the colloid dispersion coefficient and aperture field statistics; and (3) the relationship between attachment/detachment, aperture field statistics, fracture wall topography, flow rate, and ionic strength. In addition, this presentation will provide insight into the application of the random walk particle tracking technique for modeling colloid transport in variable-aperture fractures.

The EGS Collab Project: Stimulation Investigations for Geothermal Modeling Analysis and Validation

NASA Astrophysics Data System (ADS)

Blankenship, D.; Kneafsey, T. J.

2017-12-01

The US DOE's EGS Collab project team is establishing a suite of intermediate-scale ( 10-20 m) field test beds for coupled stimulation and interwell flow tests. The multiple national laboratory and university team is designing the tests to compare measured data to models to improve measurement and modeling toolsets available for use in field sites and investigations such as DOE's Frontier Observatory for Research in Geothermal Energy (FORGE) Project. Our tests will be well-controlled, in situexperiments focused on rock fracture behavior, seismicity, and permeability enhancement. Pre- and post-test modeling will allow for model prediction and validation. High-quality, high-resolution geophysical and other fracture characterization data will be collected, analyzed, and compared with models and field observations to further elucidate the basic relationships between stress, induced seismicity, and permeability enhancement. Coring through the stimulated zone after tests will provide fracture characteristics that can be compared to monitoring data and model predictions. We will also observe and quantify other key governing parameters that impact permeability, and attempt to understand how these parameters might change throughout the development and operation of an Enhanced Geothermal System (EGS) project with the goal of enabling commercial viability of EGS. The Collab team will perform three major experiments over the three-year project duration. Experiment 1, intended to investigate hydraulic fracturing, will be performed in the Sanford Underground Research Facility (SURF) at 4,850 feet depth and will build on kISMET Project findings. Experiment 2 will be designed to investigate hydroshearing. Experiment 3 will investigate changes in fracturing strategies and will be further specified as the project proceeds. The tests will provide quantitative insights into the nature of stimulation (e.g., hydraulic fracturing, hydroshearing, mixed-mode fracturing, thermal fracturing) in crystalline rock under reservoir-like stress conditions and generate high-quality, high-resolution, diverse data sets to be simulated allowing model validation. Monitoring techniques will also be evaluated under controlled conditions identifying technologies appropriate for deeper full-scale EGS sites.

Simulating flow in karst aquifers at laboratory and sub-regional scales using MODFLOW-CFP

NASA Astrophysics Data System (ADS)

Gallegos, Josue Jacob; Hu, Bill X.; Davis, Hal

2013-12-01

Groundwater flow in a well-developed karst aquifer dominantly occurs through bedding planes, fractures, conduits, and caves created by and/or enlarged by dissolution. Conventional groundwater modeling methods assume that groundwater flow is described by Darcian principles where primary porosity (i.e. matrix porosity) and laminar flow are dominant. However, in well-developed karst aquifers, the assumption of Darcian flow can be questionable. While Darcian flow generally occurs in the matrix portion of the karst aquifer, flow through conduits can be non-laminar where the relation between specific discharge and hydraulic gradient is non-linear. MODFLOW-CFP is a relatively new modeling program that accounts for non-laminar and laminar flow in pipes, like karst caves, within an aquifer. In this study, results from MODFLOW-CFP are compared to those from MODFLOW-2000/2005, a numerical code based on Darcy's law, to evaluate the accuracy that CFP can achieve when modeling flows in karst aquifers at laboratory and sub-regional (Woodville Karst Plain, Florida, USA) scales. In comparison with laboratory experiments, simulation results by MODFLOW-CFP are more accurate than MODFLOW 2005. At the sub-regional scale, MODFLOW-CFP was more accurate than MODFLOW-2000 for simulating field measurements of peak flow at one spring and total discharges at two springs for an observed storm event.

The Mpemba effect: When can hot water freeze faster than cold?

NASA Astrophysics Data System (ADS)

Jeng, Monwhea

2006-06-01

We review the Mpemba effect, where initially hot water freezes faster than initially cold water. Although the effect might appear impossible, it has been observed in numerous experiments and was discussed by Aristotle, Francis Bacon, Roger Bacon, and Descartes. It has a rich and fascinating history, including the story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon is simple to describe and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. Proposed theoretical mechanisms for the Mpemba effect and the results of contemporary experiments on the phenomenon are surveyed. The observation that hot water pipes are more likely to burst than cold water pipes is also discussed.

Study of pore pressure reaction on hydraulic fracturing

NASA Astrophysics Data System (ADS)

Trimonova, Mariia; Baryshnikov, Nikolay; Turuntaev, Sergey; Zenchenko, Evgeniy; Zenchenko, Petr

2017-04-01

We represent the results of the experimental study of the hydraulic fracture propagation influence on the fluid pore pressure. Initial pore pressure was induced by injection and production wells. The experiments were carried out according to scaling analysis based on the radial model of the fracture. All required geomechanical and hydrodynamical properties of a sample were derived from the scaling laws. So, gypsum was chosen as a sample material and vacuum oil as a fracturing fluid. The laboratory setup allows us to investigate the samples of cylindrical shape. It can be considered as an advantage in comparison with standard cubic samples, because we shouldn't consider the stress field inhomogeneity induced by the corners. Moreover, we can set 3D-loading by this setting. Also the sample diameter is big enough (43cm) for placing several wells: the fracturing well in the center and injection and production wells on two opposite sides of the central well. The experiment consisted of several stages: a) applying the horizontal pressure; b) applying the vertical pressure; c) water solution injection in the injection well with a constant pressure; d) the steady state obtaining; e) the oil injection in the central well with a constant rate. The pore pressure was recorded in the 15 points along bottom side of the sample during the whole experiment. We observe the pore pressure change during all the time of the experiment. First, the pore pressure changed due to water injection. Then we began to inject oil in the central well. We compared the obtained experimental data on the pore pressure changes with the solution of the 2D single-phase equation of pore-elasticity, and we found significant difference. The variation of the equation parameters couldn't help to resolve the discrepancy. After the experiment, we found that oil penetrated into the sample before and after the fracture initiation. This fact encouraged us to consider another physical process - the oil-water displacement. Have taken into account the phenomenon, we could find the parameter values for the best matching the experimental data with the analytical one. After such a comparison, we could estimate the permeability variation in the different directions due to changes in the pore pressure during fracturing. Thus it was found that for the correct solution of hydrodynamic problems in relation with hydraulic fracturing (for example, to estimate the production rate of the fractured well) one should take into account the change of the permeability in the vicinity of the fracture and solve nonlinear pore-elasticity problem.

A new classification and treatment protocol for combined fractures of the femoral shaft with the proximal or distal femur with closed locked intramedullary nailing: clinical experience of 63 fractures.

PubMed

Lambiris, Elias; Giannikas, Dimitrios; Galanopoulos, George; Tyllianakis, Minos; Megas, Panagiotis

2003-03-01

The medical records and radiographs of 63 patients, who were admitted between 1989-1997, with a combined femur fracture, were reviewed. Associated injuries were present in 38 (60%) patients. The combined fractures were classified into four major types depending on their anatomical position: type I, femoral shaft fracture combined with hip neck fracture; type II, femoral shaft fracture combined with a trochanteric fracture; type III, femoral shaft fracture combined with a distal femur fracture; and type IV, femoral shaft fracture combined with a proximal or distal femur fracture. The fractures were treated with locked intramedullary nailing and additional free cancellous 6.5-mm screws as needed. Fifty-six fractures healed without further operations. Of the remaining 6 fractures, 2 were material failures, 1 malunion with 3-cm shortening and external rotation of the femoral diaphysis, 2 early infections of the surgical wound, and 1 pseudarthrosis of the femoral shaft. All fractures were healed between 16 and 32 weeks (average: 20 weeks).

Monitoring underground water leakage pattern by ground penetrating radar (GPR) using 800 MHz antenna frequency

NASA Astrophysics Data System (ADS)

Amran, T. S. T.; Ismail, M. P.; Ahmad, M. R.; Amin, M. S. M.; Ismail, M. A.; Sani, S.; Masenwat, N. A.; Basri, N. S. M.

2018-01-01

Water is the most treasure natural resources, however, a huge amount of water are lost during its distribution that leads to water leakage problem. The leaks meant the waste of money and created more economic loss to treat and fix the damaged pipe. Researchers and engineers have put tremendous attempts and effort, to solve the water leakage problem especially in water leakage of buried pipeline. An advanced technology of ground penetrating radar (GPR) has been established as one of the non-destructive testing (NDT) method to detect the underground water pipe leaking. This paper focuses on the ability of GPR in water utility field especially on detection of water leaks in the underground pipeline distribution. A series of laboratory experiments were carried out using 800-MHz antenna, where the performance of GPR on detecting underground pipeline and locating water leakage was investigated and validated. A prototype to recreate water-leaking system was constructed using a 4-inch PVC pipe. Different diameter of holes, i.e. ¼ inch, ½ inch, and ¾ inch, were drilled into the pipe to simulate the water leaking. The PVC pipe was buried at the depth of 60 cm into the test bed that was filled with dry sand. 15 litres of water was injected into the PVC pipe. The water leakage patterns in term of radargram data were gathered. The effectiveness of the GPR in locating the underground water leakage was ascertained, after the results were collected and verified.

The Collection of Ice in Jet A-1 Fuel Pipes

NASA Astrophysics Data System (ADS)

Maloney, Thomas C.

Ice collection and blockages in fuel systems have been of interest to the aerospace community since their discovery in the late 1950's when a B-52 crashed. A recent growth of interest was provoked by several incidents that occurred within the last few years. This study seeks to understand the underlying principles of ice growth in fuel flow systems. Tests were performed in a recirculated fuel system with a fuel tank that held approximately 115 gallons of Jet A-1 fuel and ice accumulation was observed in two removable test pipes. The setup was in an altitude chamber capable of -60 °F and the experiments involved full scale flow components. Initially, tests were done to better understand the system and variables that effected accumulation. First, initial conditions within the test pipes were varied. Next, pipe geometry, pipe surface properties, initial water content of the fuel and heat transfer from the fuel pipe were varied. As a result of the tests, observations were made about other effects involved in the study. The effects include: the result of sequentially run tests, the effect of the fuel on the freezing temperature of the entrained water, the effect of ice accumulation on pipe welds, and the effect of the test pipe entrance and exit flow conditions on ice accumulation. The results of initial tests were qualitative. Later quantitative tests were done to demonstrate the dependence of temperature, Reynolds number, and heat transfer on ice accumulation. Tests were quantified with a pressure increase across the pipe sections that was normalized by the expected theoretical initial pressure. As a result of these tests the effect of contamination in the fuel was revealed. For ease of reference, the initial tests were called "stage I" and the later tests were called "stage II". The results of stage I showed that accumulation of soft ice was greatest when a layer of hard ice had initially formed on the pipe surface. Stainless steel collected more ice than Teflon® and there was a lack of a preferential accumulation region downstream of a pipe bend. A greater heat transfer from the pipe increased ice accumulation for aluminum that was made rough with 80 grit sand paper, and for Teflon®. Water was shown to collect in the pipe system as the number of tests increased and the freeze temperature of either the hard or soft ice was about 0 °C. Finally, results of "stage I" tests showed that stainless steel pipe welds were a preferred sight for ice to accumulate. Repeatability was done first in stage II and the normalized pressure increase for two 3/42 un-insulated pipe tests were within 7%. Normalized pressure increase across a pipe was shown to increase as Reynolds number decreased. A 50% increase in Reynolds number led to a 40% decrease in characteristic normalized pressure increase (CNPI). Tests were done at three temperatures and ice accumulated the most at -11 °C. The CNPI at -11 °C was about three times greater than the CNPI at -7.4 °C and about sixty times greater than the CNPI at -19.4 C. A greater heat transfer from the fuel pipe increased ice accumulation. For the amount of time that the tests ran, the total normalized pressure increase was about .9 greater for an un-insulated pipe than for an insulated pipe. Contamination in the fuel increased the amount of soft ice that collected in the system. The CNPI for the more contaminated fuel was more than double the case with less contaminated fuel. Possible solutions for the prevention or decrease of ice accumulation in aircraft fuel systems based on the results of this study are insulated pipes, a change in the type of pipe material, a higher fuel flow rate and cleaner fuel. The fuel temperature could also be altered to avoid temperatures where the most ice accumulates.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerard, R.; Malekian, C.; Meessen, O.

The Leak Before Break (LBB) concept allows to eliminate from the design basis the double-ended guillotine break of the primary loop piping, provided it can be demonstrated by a fracture mechanics analysis that a through-wall flaw, of a size giving rise to a leakage still well detectable by the plant leak detection systems, remains stable even under accident conditions (including the Safe Shutdown Earthquake (SSE)). This concept was successfully applied to the primary loop piping of several Belgian Pressurized Water Reactor (PWR) units, operated by the Utility Electrabel. One of the main benefits is to permit justification of supports inmore » the primary loop and justification of the integrity of the reactor pressure vessel and internals in case of a Loss Of Coolant Accident (LOCA) in stretch-out conditions. For two of the Belgian PWR units, the LBB approach also made it possible to reduce the number of large hydraulic snubbers installed on the primary coolant pumps. Last but not least, the LBB concept also facilitates the steam generator replacement operations, by eliminating the need for some pipe whip restraints located close to the steam generator. In addition to the U.S. regulatory requirements, the Belgian safety authorities impose additional requirements which are described in details in a separate paper. An novel aspect of the studies performed in Belgium is the way in which residual loads in the primary loop are taken into account. Such loads may result from displacements imposed to close the primary loop in a steam generator replacement operation, especially when it is performed using the {open_quote}two cuts{close_quotes} technique. The influence of such residual loads on the LBB margins is discussed in details and typical results are presented.« less

Thermal-hydrodynamic-chemical (THC) modeling based on geothermal field data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiryukhin, Alexey; Xu, Tianfu; Pruess, Karsten

Data on fluid chemistry and rock mineralogy are evaluated for a number of geothermal fields located in the volcanic arc of Japan and Kamchatka, Russia, Common chemical characteristics are identified and used to define scenarios for detailed numerical modeling of coupled thermal hydrodynamic chemical (THC) processes. The following scenarios of parental geothermal fluid upflow were studied: (1) single-phase conditions, 260 C at the bottom ( Ogiri type); (2) two-phase conditions, 300 C at the bottom ( Hatchobaru type); and (3) heat pipe conditions, 260 C at the bottom ( Matsukawa type). THC modeling for the single-phase upflow scenario shows wairakite,more » quartz, K-feld spar and chlorite formed as the principal secondary minerals in the production zone, and illite-smectite formed below 230 C. THC modeling of the two-phase upflow shows that quartz, K-feldspar (microcline), wairakite and calcite precipitate in the model as principal secondary minerals in the production zone. THC modeling of heat pipe conditions shows no significant secondary deposition of minerals (quartz, K-feldspar, zeolites) in the production zone. The influence of thermodynamic and kinetic parameters of chemical interaction, and of mass fluxes on mineral phase changes, was found to be significant, depending on the upflow regime. It was found that no parental geothermal fluid inflow is needed for zeolite precipitation, which occurs above 140 C in saturated andesite, provided that the porosity is greater than 0.001. In contrast, quartz and K-feldspar precipitation may result in a significant porosity reduction over a hundred-year time scale under mass flux conditions, and complete fracture sealing will occur given sufficient time under either single-phase or two-phase upflow scenarios. A heat pipe scenario shows no significant porosity reduction due to lack of secondary mineral phase deposition.« less

Does the Spine Surgeon’s Experience Affect Fracture Classification, Assessment of Stability, and Treatment Plan in Thoracolumbar Injuries?

PubMed Central

Kanna, Rishi Mugesh; Schroeder, Gregory D.; Oner, Frank Cumhur; Vialle, Luiz; Chapman, Jens; Dvorak, Marcel; Fehlings, Michael; Shetty, Ajoy Prasad; Schnake, Klaus; Kandziora, Frank; Vaccaro, Alexander R.

2017-01-01

Study Design: Prospective survey-based study. Objectives: The AO Spine thoracolumbar injury classification has been shown to have good reproducibility among clinicians. However, the influence of spine surgeons’ clinical experience on fracture classification, stability assessment, and decision on management based on this classification has not been studied. Furthermore, the usefulness of varying imaging modalities including radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) in the decision process was also studied. Methods: Forty-one spine surgeons from different regions, acquainted with the AOSpine classification system, were provided with 30 thoracolumbar fractures in a 3-step assessment: first radiographs, followed by CT and MRI. Surgeons classified the fracture, evaluated stability, chose management, and identified reasons for any changes. The surgeons were divided into 2 groups based on years of clinical experience as <10 years (n = 12) and >10 years (n = 29). Results: There were no significant differences between the 2 groups in correctly classifying A1, B2, and C type fractures. Surgeons with less experience had more correct diagnosis in classifying A3 (47.2% vs 38.5% in step 1, 73.6% vs 60.3% in step 2 and 77.8% vs 65.5% in step 3), A4 (16.7% vs 24.1% in step 1, 72.9% vs 57.8% in step 2 and 70.8% vs 56.0% in step3) and B1 injuries (31.9% vs 20.7% in step 1, 41.7% vs 36.8% in step 2 and 38.9% vs 33.9% in step 3). In the assessment of fracture stability and decision on treatment, the less and more experienced surgeons performed equally. The selection of a particular treatment plan varied in all subtypes except in A1 and C type injuries. Conclusion: Surgeons’ experience did not significantly affect overall fracture classification, evaluating stability and planning the treatment. Surgeons with less experience had a higher percentage of correct classification in A3 and A4 injuries. Despite variations between them in classification, the assessment of overall stability and management decisions were similar between the 2 groups. PMID:28815158

Does the Spine Surgeon's Experience Affect Fracture Classification, Assessment of Stability, and Treatment Plan in Thoracolumbar Injuries?

PubMed

Rajasekaran, Shanmuganathan; Kanna, Rishi Mugesh; Schroeder, Gregory D; Oner, Frank Cumhur; Vialle, Luiz; Chapman, Jens; Dvorak, Marcel; Fehlings, Michael; Shetty, Ajoy Prasad; Schnake, Klaus; Kandziora, Frank; Vaccaro, Alexander R

2017-06-01

Prospective survey-based study. The AO Spine thoracolumbar injury classification has been shown to have good reproducibility among clinicians. However, the influence of spine surgeons' clinical experience on fracture classification, stability assessment, and decision on management based on this classification has not been studied. Furthermore, the usefulness of varying imaging modalities including radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) in the decision process was also studied. Forty-one spine surgeons from different regions, acquainted with the AOSpine classification system, were provided with 30 thoracolumbar fractures in a 3-step assessment: first radiographs, followed by CT and MRI. Surgeons classified the fracture, evaluated stability, chose management, and identified reasons for any changes. The surgeons were divided into 2 groups based on years of clinical experience as <10 years (n = 12) and >10 years (n = 29). There were no significant differences between the 2 groups in correctly classifying A1, B2, and C type fractures. Surgeons with less experience had more correct diagnosis in classifying A3 (47.2% vs 38.5% in step 1, 73.6% vs 60.3% in step 2 and 77.8% vs 65.5% in step 3), A4 (16.7% vs 24.1% in step 1, 72.9% vs 57.8% in step 2 and 70.8% vs 56.0% in step3) and B1 injuries (31.9% vs 20.7% in step 1, 41.7% vs 36.8% in step 2 and 38.9% vs 33.9% in step 3). In the assessment of fracture stability and decision on treatment, the less and more experienced surgeons performed equally. The selection of a particular treatment plan varied in all subtypes except in A1 and C type injuries. Surgeons' experience did not significantly affect overall fracture classification, evaluating stability and planning the treatment. Surgeons with less experience had a higher percentage of correct classification in A3 and A4 injuries. Despite variations between them in classification, the assessment of overall stability and management decisions were similar between the 2 groups.

An analysis of pipe flange connections using epoxy adhesives/anaerobic sealant instead of gaskets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sawa, T.; Sasaki, R.; Yoneno, M.

1995-11-01

This paper deals with the strength and the sealing performance of pipe flange connections combining the bonding force of adhesives with the clamping force of bolts. The epoxy adhesives or anaerobic sealants are bonded at the interface partially instead of gaskets in pipe flange connections. The stress distribution in the epoxy adhesives (anaerobic sealant), which governs the sealing performance, and the variations in axial bolt force are analyzed, using an axisymmetrical theory of elasticity, when an internal pressure is applied to a connection in which two pipe flanges are clamped together buy bolts and nuts with an initial clamping forcemore » after being joined by epoxy adhesives or anaerobic sealant. In addition, a method for estimating the strength of the combination connection is demonstrated. Experiments are performed and the analytical results are consistent with the experimental results concerning the variation in axial bolt force and the strength of combination connections. It can be seen that the strength of connections increases with a decrease in the bolt pitch circle diameter. Furthermore, it is seen that the sealing performance of such combination connections in which the interface is bonded partially is improved over that of pipe flange connections with metallic gaskets.« less

Residual stresses in a stainless steel - titanium alloy joint made with the explosive technique

NASA Astrophysics Data System (ADS)

Taran, Yu V.; Balagurov, A. M.; Sabirov, B. M.; Evans, A.; Davydov, V.; Venter, A. M.

2012-02-01

Joining of pipes from stainless steel (SS) and titanium (Ti) alloy still experience serious technical problems. Recently, reliable and hermetic joining of SS and Ti pipes has been achieved with the explosive bonding technique in the Russian Federal Nuclear Center. Such adapters are earmarked for use at the future International Linear Collider. The manufactured SS-Ti adapters have excellent mechanical behavior at room and liquid nitrogen temperatures, during high-pressure tests and thermal cycling. We here report the first neutron diffraction investigation of the residual stresses in a SS-Ti adapter on the POLDI instrument at the SINQ spallation source. The strain scanning across the adapter walls into the SS-SS and SS-Ti pipes sections encompassed measurement of the axial, radial and hoop strain components, which were transformed into residual stresses. The full stress information was successfully determined for the three steel pipes involved in the joint. The residual stresses do not exceed 300 MPa in magnitude. All stress components have tensile values close to the adapter internal surface, whilst they are compressive close to the outer surface. The strong incoherent and weak coherent neutron scattering cross-sections of Ti did not allow for the reliable determination of stresses inside the titanic pipe.

On the universality of inertial energy in the log layer of turbulent boundary layer and pipe flows

NASA Astrophysics Data System (ADS)

Chung, D.; Marusic, I.; Monty, J. P.; Vallikivi, M.; Smits, A. J.

2015-07-01

Recent experiments in high Reynolds number pipe flow have shown the apparent obfuscation of the behaviour in spectra of streamwise velocity fluctuations (Rosenberg et al. in J Fluid Mech 731:46-63, 2013). These data are further analysed here from the perspective of the behaviour in second-order structure functions, which have been suggested as a more robust diagnostic to assess scaling behaviour. A detailed comparison between pipe flows and boundary layers at friction Reynolds numbers of 5000-20,000 reveals subtle differences. In particular, the slope of the pipe flow structure function decreases with increasing wall distance, departing from the expected slope in a manner that is different to boundary layers. Here, , the slope of the log law in the streamwise turbulence intensity profile at high Reynolds numbers. Nevertheless, the structure functions for both flows recover the slope in the log layer sufficiently close to the wall, provided the Reynolds number is also high enough to remain in the log layer. This universality is further confirmed in very high Reynolds number data from measurements in the neutrally stratified atmospheric surface layer. A simple model that accounts for the `crowding' effect near the pipe axis is proposed in order to interpret the aforementioned differences.

Experimental Study on the Thermal Start-Up Performance of the Graphene/Water Nanofluid-Enhanced Solar Gravity Heat Pipe

PubMed Central

Zhao, Shanguo; Xu, Guoying; Wang, Ning; Zhang, Xiaosong

2018-01-01

The solar gravity heat pipe has been widely used for solar thermal water heating because of its high efficient heat transfer and thermal diode characteristics. Operated on fluctuant and low intensity solar radiation conditions, a solar gravity heat pipe may frequently start up. This severely affects its solar collection performance. To enhance the thermal performance of the solar gravity heat pipe, this study proposes using graphene/water nanofluid as the working fluid instead of deionized water. The stability of the prepared graphene/water nanofluid added with PVP was firstly investigated to obtain the optimum mass ratios of the added dispersant. Thermophysical properties—including the thermal conductivity and viscosity—of nanofluid with various graphene nanoplatelets (GNPs) concentrations were measured at different temperatures for further analysis. Furthermore, based on the operational evaluation on a single heat pipe’s start-up process, the performance of nanofluid-enhanced solar gravity heat pipes using different concentrations of GNPs were compared by using water heating experiments. Results indicated that the use of 0.05 wt % graphene/water nanofluid instead of water could achieve a 15.1% and 10.7% reduction in start-up time under 30 and 60 W input heating conditions, respectively. Consequently, a higher thermal efficiency for solar collection could be expected. PMID:29382094

Numerical analysis of flow resistance and heat transfer in the transitional regime of pipe flow with twisted-tape turbulators

NASA Astrophysics Data System (ADS)

Rossi, R.; Cattani, L.; Mocerino, A.; Bozzoli, F.; Rainieri, S.; Caminati, R.; Pagliarini, G.

2017-11-01

In this paper, we present the numerical analysis of the fully developed ow and heat transfer in pipes equipped with twisted-tape inserts in the laminar to transitional flow regime. The flow Reynolds number ranges from 210 to 3100 based on the pipe diameter, whereas the Prandtl number of the working fluid, a 40% mixture of water and ethylene glycol, is about 45 at the average film temperature. The numerical study is carried out via Scale Adaptive Simulations (SAS) where the k-ω SST model is employed for turbulence modeling. Using SAS and low-dissipation discretization schemes, the present study shows that it is possible to capture the transition from the laminar regime to the pulsating or pseudo-laminar flow regime induced by the twisted-tape at low Reynolds numbers, as well as the transition to moderate turbulent regime at the higher, yet non-turbulent for smooth pipes, range of Reynolds numbers. Numerical results, validated against experiments performed in a dedicated test rig, show very good agreement with measured data and an increase of the friction factor and Nusselt number in the range of 4 to 7 times and 6 to 15 times, respectively, of the values for an empty pipe.

Proceedings of the Joint IAEA/CSNI Specialists` Meeting on Fracture Mechanics Verification by Large-Scale Testing held at Pollard Auditorium, Oak Ridge, Tennessee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pugh, C.E.; Bass, B.R.; Keeney, J.A.

This report contains 40 papers that were presented at the Joint IAEA/CSNI Specialists` Meeting Fracture Mechanics Verification by Large-Scale Testing held at the Pollard Auditorium, Oak Ridge, Tennessee, during the week of October 26--29, 1992. The papers are printed in the order of their presentation in each session and describe recent large-scale fracture (brittle and/or ductile) experiments, analyses of these experiments, and comparisons between predictions and experimental results. The goal of the meeting was to allow international experts to examine the fracture behavior of various materials and structures under conditions relevant to nuclear reactor components and operating environments. The emphasismore » was on the ability of various fracture models and analysis methods to predict the wide range of experimental data now available. The individual papers have been cataloged separately.« less

Early treatment of penile fractures: our experience.

PubMed

García Gómez, Borja; Romero, Javier; Villacampa, Felipe; Tejido, Angel; Díaz, Rafael

2012-09-01

To report our experience in early surgery of penile fractures. We review retrospectively all the cases that underwent surgery at our center from 1989 to 2009, with a total of 24. The cause of the fracture was sexual intercourse in most cases, and in all of them, surgical management was performed according to clinical presentation and physical exploration. In only 7 cases an ultrasound was performed as a complementary test. Early surgery allows prompt resolution of the problem with excellent functional outcomes and little side effects. The prognosis after emergency surgery was excellent in this review.

Prediction of Fracture Initiation in Hot Compression of Burn-Resistant Ti-35V-15Cr-0.3Si-0.1C Alloy

NASA Astrophysics Data System (ADS)

Zhang, Saifei; Zeng, Weidong; Zhou, Dadi; Lai, Yunjin

2015-11-01

An important concern in hot working of metals is whether the desired deformation can be accomplished without fracture of the material. This paper builds a fracture prediction model to predict fracture initiation in hot compression of a burn-resistant beta-stabilized titanium alloy Ti-35V-15Cr-0.3Si-0.1C using a combined approach of upsetting experiments, theoretical failure criteria and finite element (FE) simulation techniques. A series of isothermal compression experiments on cylindrical specimens were conducted in temperature range of 900-1150 °C, strain rate of 0.01-10 s-1 first to obtain fracture samples and primary reduction data. Based on that, a comparison of eight commonly used theoretical failure criteria was made and Oh criterion was selected and coded into a subroutine. FE simulation of upsetting experiments on cylindrical specimens was then performed to determine the fracture threshold values of Oh criterion. By building a correlation between threshold values and the deforming parameters (temperature and strain rate, or Zener-Hollomon parameter), a new fracture prediction model based on Oh criterion was established. The new model shows an exponential decay relationship between threshold values and Zener-Hollomon parameter (Z), and the relative error of the model is less than 15%. This model was then applied successfully in the cogging of Ti-35V-15Cr-0.3Si-0.1C billet.

Massive hydraulic fracture mapping and characterization program. Surface potential data for Wattenberg 1975--1976 experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCann, R.P.; Bartel, L.C.; Keck, L.J.

1977-08-01

Three massive hydraulic fracture experiments for natural gas stimulation were conducted by Halliburton for AMOCO in the Wattenberg field northeast of Denver, Colorado. The experiments were conducted on three wells--Martin Hart ''E'' No. 1, Salazar G.U. No. 1, and UPRR-22P. All three wells were open hole and the fracture zone was located at a depth of approximately 8000 ft. All were treated with approximately 300,000 gal of fluid and 600,000 lb of proppant. The surface electrical potential technique was used to attempt characterization and mapping of the fracture. The noise perturbating the system consists of telluric currents, currents from industrialmore » sources, and natural local currents. It is difficult to determine the exact signal-to-noise ratio or the exact origin of the noise without exhaustive field measurements and data analysis. However, improvements have been made in the surface potential gradient technique since the early developmental stage of the diagnostic program. To aid in the interpretation of the field data, mathematical modeling efforts have been undertaken. The model utilizes the Green's function integral equation approach where the so-called half-space Green's function is used. The model calculates the potential difference that exists at the surface as a function of fracturing conditions. Data analysis indicates that the fracture orientation for all three wells lies in a SE to NW direction and that the fractures are asymmetric.« less

Experimental and numerical simulation of dissolution and precipitation: implications for fracture sealing at Yucca Mountain, Nevada

NASA Astrophysics Data System (ADS)

Dobson, Patrick F.; Kneafsey, Timothy J.; Sonnenthal, Eric L.; Spycher, Nicolas; Apps, John A.

2003-05-01

Plugging of flow paths caused by mineral precipitation in fractures above the potential repository at Yucca Mountain, Nevada could reduce the probability of water seeping into the repository. As part of an ongoing effort to evaluate thermal-hydrological-chemical (THC) effects on flow in fractured media, we performed a laboratory experiment and numerical simulations to investigate mineral dissolution and precipitation under anticipated temperature and pressure conditions in the repository. To replicate mineral dissolution by vapor condensate in fractured tuff, water was flowed through crushed Yucca Mountain tuff at 94 °C. The resulting steady-state fluid composition had a total dissolved solids content of about 140 mg/l; silica was the dominant dissolved constituent. A portion of the steady-state mineralized water was flowed into a vertically oriented planar fracture in a block of welded Topopah Spring Tuff that was maintained at 80 °C at the top and 130 °C at the bottom. The fracture began to seal with amorphous silica within 5 days. A 1-D plug-flow numerical model was used to simulate mineral dissolution, and a similar model was developed to simulate the flow of mineralized water through a planar fracture, where boiling conditions led to mineral precipitation. Predicted concentrations of the major dissolved constituents for the tuff dissolution were within a factor of 2 of the measured average steady-state compositions. The mineral precipitation simulations predicted the precipitation of amorphous silica at the base of the boiling front, leading to a greater than 50-fold decrease in fracture permeability in 5 days, consistent with the laboratory experiment. These results help validate the use of a numerical model to simulate THC processes at Yucca Mountain. The experiment and simulations indicated that boiling and concomitant precipitation of amorphous silica could cause significant reductions in fracture porosity and permeability on a local scale. However, differences in fluid flow rates and thermal gradients between the experimental setup and anticipated conditions at Yucca Mountain need to be factored into scaling the results of the dissolution/precipitation experiments and associated simulations to THC models for the potential Yucca Mountain repository.

Checking a Conceptual Model for Groundwater Flow in the Fractured Rock at Äspö, Sweden

NASA Astrophysics Data System (ADS)

Kröhn, K. P.

2015-12-01

The underground Hard Rock Laboratory (HRL) at Äspö, Sweden, is located in granitic rock and dedicated to investigations concerning deep geological disposal of radioactive waste. Several in-situ experiments have been performed in the HRL, among them the recent Buffer-Rock Interaction Experiment (BRIE) and, on a much larger scale, the long-term Prototype Repository (PR) experiment.Interpretation of such experiments requires a profound understanding of the groundwater flow system. Often assumed is a conceptual model where the so-called "intact rock" is interspersed with stochastically distributed fractures. It is also a common assumption, though, that fractures in granite exist on all length-scales implying that the hydraulically relevant rock porosity is basically made up of micro fractures. The conceptual approach of GRS' groundwater flow code d3f thus appeared to be fitting where large fractures are represented discretely by lower-dimensional features while the remaining set of smaller fractures - also called "background fractures" - is assumed to act like an additional homogeneous continuum besides what is believed to be the undisturbed matrix. This approach was applied to a hydraulic model of the BRIE in a cube-like domain of 40 m side length including drifts, boreholes and three intersecting large fractures. According to observations at the underground rock laboratories Stripa and the HRL a narrow zone of reduced permeability - called "skin" - was additionally arranged around all geotechnical openings. Calibration of the model resulted in a considerable increase of matrix permeability due to adding the effect of the background fractures. To check the validity of this approach the calibrated data for the BRIE were applied to a model for the PR which is also located in the HRL but at quite some distance. The related brick-shaped model domain has a size of 200 m x 150 m x 50 m. Fitting the calculated outflow from the rock to the measured outflow distribution along the PR-tunnel and the outflow into the six "deposition boreholes" nevertheless required only a moderate modification of the initially used permeabilities. By and large the chosen approach for the BRIE can thus be considered to have been successfully transferred to the PR.

Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

2018-02-01

Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

ClimatePipes: User-Friendly Data Access, Manipulation, Analysis & Visualization of Community Climate Models

NASA Astrophysics Data System (ADS)

Chaudhary, A.; DeMarle, D.; Burnett, B.; Harris, C.; Silva, W.; Osmari, D.; Geveci, B.; Silva, C.; Doutriaux, C.; Williams, D. N.

2013-12-01

The impact of climate change will resonate through a broad range of fields including public health, infrastructure, water resources, and many others. Long-term coordinated planning, funding, and action are required for climate change adaptation and mitigation. Unfortunately, widespread use of climate data (simulated and observed) in non-climate science communities is impeded by factors such as large data size, lack of adequate metadata, poor documentation, and lack of sufficient computational and visualization resources. We present ClimatePipes to address many of these challenges by creating an open source platform that provides state-of-the-art, user-friendly data access, analysis, and visualization for climate and other relevant geospatial datasets, making the climate data available to non-researchers, decision-makers, and other stakeholders. The overarching goals of ClimatePipes are: - Enable users to explore real-world questions related to climate change. - Provide tools for data access, analysis, and visualization. - Facilitate collaboration by enabling users to share datasets, workflows, and visualization. ClimatePipes uses a web-based application platform for its widespread support on mainstream operating systems, ease-of-use, and inherent collaboration support. The front-end of ClimatePipes uses HTML5 (WebGL, Canvas2D, CSS3) to deliver state-of-the-art visualization and to provide a best-in-class user experience. The back-end of the ClimatePipes is built around Python using the Visualization Toolkit (VTK, http://vtk.org), Climate Data Analysis Tools (CDAT, http://uv-cdat.llnl.gov), and other climate and geospatial data processing tools such as GDAL and PROJ4. ClimatePipes web-interface to query and access data from remote sources (such as ESGF). Shown in the figure is climate data layer from ESGF on top of map data layer from OpenStreetMap. The ClimatePipes workflow editor provides flexibility and fine grained control, and uses the VisTrails (http://www.vistrails.org) workflow engine in the backend.

How reactive fluids alter fracture walls and affect shale-matrix accessibility

NASA Astrophysics Data System (ADS)

Fitts, J. P.; Deng, H.; Peters, C. A.

2014-12-01

Predictions of mass transfer across fracture boundaries and fluid flow in fracture networks provide fundamental inputs into risk and life cycle assessments of geologic energy technologies including oil and gas extraction, geothermal energy systems and geologic CO2 storage. However, major knowledge gaps exist due to the lack of experimental observations of how reactive fluids alter the pore structures and accessible surface area within fracture boundaries that control the mass transfer of organics, metals and salts, and influence fluid flow within the fracture. To investigate the fracture and rock matrix properties governing fracture boundary alteration, we developed a new flow-through cell that enables time-dependent 2D x-ray imaging of mineral dissolution and/or precipitation at a fracture surface. The parallel plate design provides an idealized fracture geometry to investigate the relationship between flow rate, reaction rate, and mineral spatial heterogeneity and variation. In the flow-cell, a carbonate-rich sample of Eagle Ford shale was reacted with acidified brine. The extent and rate of mineral dissolution were correlated with calcite abundance relative to less soluble silicate minerals. Three-dimensional x-ray tomography of the reacted fracture wall shows how calcite dissolution left behind a porous network of silicate minerals. And while this silicate network essentially preserved the location of the initial fracture wall, the pore network structures within the fracture boundary were dramatically altered, such that the accessible surface area of matrix components increased significantly. In a second set of experiments with a limestone specimen, however, the extent of dissolution and retreat of the fracture wall was not strictly correlated with the occurrence of calcite. Instead, the pattern and extent of dissolution suggested secondary causes such as calcite morphology, the presence of argillaceous minerals and other diagenetic features. Our experiments show that while calcite dissolution is the primary geochemical driver of fracture wall alterations, hydrodynamic properties and matrix accessibility within fracture boundaries evolve based on a complex relationship between mineral spatial heterogeneity and variation, fluid chemistry and flow rate.

Understanding hydraulic fracturing: a multi-scale problem.

PubMed

Hyman, J D; Jiménez-Martínez, J; Viswanathan, H S; Carey, J W; Porter, M L; Rougier, E; Karra, S; Kang, Q; Frash, L; Chen, L; Lei, Z; O'Malley, D; Makedonska, N

2016-10-13

Despite the impact that hydraulic fracturing has had on the energy sector, the physical mechanisms that control its efficiency and environmental impacts remain poorly understood in part because the length scales involved range from nanometres to kilometres. We characterize flow and transport in shale formations across and between these scales using integrated computational, theoretical and experimental efforts/methods. At the field scale, we use discrete fracture network modelling to simulate production of a hydraulically fractured well from a fracture network that is based on the site characterization of a shale gas reservoir. At the core scale, we use triaxial fracture experiments and a finite-discrete element model to study dynamic fracture/crack propagation in low permeability shale. We use lattice Boltzmann pore-scale simulations and microfluidic experiments in both synthetic and shale rock micromodels to study pore-scale flow and transport phenomena, including multi-phase flow and fluids mixing. A mechanistic description and integration of these multiple scales is required for accurate predictions of production and the eventual optimization of hydrocarbon extraction from unconventional reservoirs. Finally, we discuss the potential of CO2 as an alternative working fluid, both in fracturing and re-stimulating activities, beyond its environmental advantages.This article is part of the themed issue 'Energy and the subsurface'. © 2016 The Author(s).

Understanding hydraulic fracturing: a multi-scale problem

PubMed Central

Hyman, J. D.; Jiménez-Martínez, J.; Viswanathan, H. S.; Carey, J. W.; Porter, M. L.; Rougier, E.; Karra, S.; Kang, Q.; Frash, L.; Chen, L.; Lei, Z.; O’Malley, D.; Makedonska, N.

2016-01-01

Despite the impact that hydraulic fracturing has had on the energy sector, the physical mechanisms that control its efficiency and environmental impacts remain poorly understood in part because the length scales involved range from nanometres to kilometres. We characterize flow and transport in shale formations across and between these scales using integrated computational, theoretical and experimental efforts/methods. At the field scale, we use discrete fracture network modelling to simulate production of a hydraulically fractured well from a fracture network that is based on the site characterization of a shale gas reservoir. At the core scale, we use triaxial fracture experiments and a finite-discrete element model to study dynamic fracture/crack propagation in low permeability shale. We use lattice Boltzmann pore-scale simulations and microfluidic experiments in both synthetic and shale rock micromodels to study pore-scale flow and transport phenomena, including multi-phase flow and fluids mixing. A mechanistic description and integration of these multiple scales is required for accurate predictions of production and the eventual optimization of hydrocarbon extraction from unconventional reservoirs. Finally, we discuss the potential of CO2 as an alternative working fluid, both in fracturing and re-stimulating activities, beyond its environmental advantages. This article is part of the themed issue ‘Energy and the subsurface’. PMID:27597789

Transmissivity Changes and Microseismicity Induced by Small-Scale Hydraulic Fracturing Tests in Crystalline Rock

NASA Astrophysics Data System (ADS)

Jalali, Mohammadreza; Gischig, Valentin; Doetsch, Joseph; Näf, Rico; Krietsch, Hannes; Klepikova, Maria; Amann, Florian; Giardini, Domenico

2018-03-01

Multiple meter-scale hydraulic fracturing (HF) experiments were executed in the crystalline rock at the Grimsel Test Site, Switzerland. The effect of the HF on the rock transmissivity has been quantified with hydraulic tests before and after each HF experiment. We observe transmissivity enhancement of 2 to 3 orders of magnitude and a change in the dominant flow regime after most of the HF tests. From microseismicity induced by the HF, we do not observe a systematic correlation between transmissivity enhancement and event numbers, frequency-magnitude distribution, or maximum magnitude. However, the radii of hydraulic fractures inferred independently from seismicity clouds and hydraulic responses coincide, implying that slip along fractures is the common underlying mechanism for transmissivity increase and seismicity.

Failure Analysis on Tail Rotor Teeter Pivot Bolt on a Helicopter

NASA Astrophysics Data System (ADS)

Qiang, WANG; Zi-long, DONG

2018-03-01

Tail rotor teeter pivot bolt of a helicopter fractured when in one flight. Failure analysis on the bolt was finished in laboratory. Macroscopic observation of the tailor rotor teeter pivot bolt, macro and microscopic inspection on the fracture surface of the bolt was carried out. Chemical components and metallurgical structure was also carried out. Experiment results showed that fracture mode of the tail rotor teeter pivot bolt is fatigue fracture. Fatigue area is over 80% of the total fracture surface, obvious fatigue band characteristics can be found at the fracture face. According to the results were analyzed from the macroscopic and microcosmic aspects, fracture reasons of the tail rotor teeter pivot bolt were analyzed in detail

Reaction processes and permeability changes during CO2-rich brine flow through fractured Portland cement

NASA Astrophysics Data System (ADS)

Abdoulghafour, H.; Luquot, L.; Gouze, P.

2012-12-01

So far, cement alteration was principally studied experimentally using batch reactor (with static or renewed fluid). All exhibit similar carbonation mechanisms. The acidic solution, formed by the dissolution of the CO2 into the pore water or directly surrounding the cement sample, diffuses into the cement and induces dissolution reactions of the cement hydrates in particular portlandite and CSH. The calcium released by the dissolution of these calcium bearing phases combining with carbonate ions of the fluid forms calcium carbonates. The cement pH, initially around 13, falls to values where carbonate ion is the most dominant element (pH ~ 9), then CaCO3 phases can precipitate. These studies mainly associate carbonation process with a reduction of porosity and permeability. Indeed an increase of volume (about 10%) is expected during the formation of calcite from portlandite (equation 2) assuming a stoichiometric reaction. Here we investigated the cement alteration mechanisms in the frame of a controlled continuous renewal of CO2-rich fluid in a fracture. This situation is that expected when seepage is activated by the mechanical failure of the cement material that initially seals two layers of distinctly different pressure: the storage reservoir and the aquifer above the caprock, for instance. We study the effect of flow rates from quasi-static flow to higher flow rates for well-connected fractures. In the quasi-static case we observed an extensive conversion of portlandite (Ca(OH)2) to calcite in the vicinity of the fracture similar to that observed in the published batch experiments. Eventually, the fracture was almost totally healed. The experiments with constant flow revealed a different behaviour triggered by the continuous renewing of the reactants and withdrawal of reaction products. We showed that calcite precipitation is more efficient for low flow rate. With intermediate flow rate, we measured that permeability increases slowly at the beginning of the experiment and then remains constant due to calcite precipitation in replacement of CSH and CH into fracture border. With higher flow rate, we measured a constant permeability which can be explained by the development of a highly hydrated Si-rich zone which maintains the initial fracture aperture during all over the experiment while noticeable mass is released from the sample. These preliminary results emphasize that more complex behaviours than that envisaged from batch experiments may take place in the vicinity of flowing fractures. We demonstrated that if only micro-cracks appear in the cement well, carbonation reaction may heal these micro-cracks and mitigate leakage whereas conductive fractures allowing high flow may represent a risk of perennial leakage because the net carbonation process, including the calcite precipitation and its subsequent re-dissolution, is sufficiently to heal the fracture. However, the precipitation of Si-rich amorphous phases may maintain the initial fracture aperture and limit the leakage rate. Keywords: leakage, cement alteration, flow rate, fracture, permeability changes, reaction processes.

Management and outcomes of penile fracture: 10 years' experience from a tertiary care center.

PubMed

Özorak, Alper; Hoşcan, Mustafa Burak; Oksay, Taylan; Güzel, Ahmet; Koşar, Alim

2014-03-01

To evaluate our experience on diagnosis and management of penile fractures. This retrospective study included 31 patients who were treated for penile fracture between 2002 and 2012. We analyzed the etiology of penile fracture, concomitant pathologies such as urethral injury, deep or superficial dorsal vein ruptures, treatment modalities (surgery or conservative treatment) and complications of treatment modalities. The mean age of the patients was 32 years (range, 23-47 years). In 27 patients (87%), the cause of penile fracture was sexual intercourse. Patients presented with swelling, pain and popping or cracking sound in penis. The diagnosis of penile fracture was established clinically in all of the patients. There were no urethral injuries or dorsal vein ruptures. Ten patients who refused surgical treatment were treated conservatively and remaining 21 patients with early surgical intervention. Among conservatively treated patients, two suffered from erectile dysfunction, two from painful erection and another two from penile curvature. No serious complications such as erectile dysfunction, penile curvature or painful erection were observed in surgically treated patients. Penile fracture can be diagnosed easily with history and physical examination, and favorable functional results can be achieved with early surgical repair.

A generalized genetic framework for the development of sinkholes and Karst in Florida, U.S.A.

NASA Astrophysics Data System (ADS)

Beck, Barry F.

1986-03-01

Karst topography in Florida is developed on the Tertiary limestones of the Floridan aquifer Post-depositional diagenesis and solution have made these limestones highly permeable, T=ca. 50,000 m2/d. Zones of megaporosity have formed at unconformities, and dissolution has enlarged joints and fractures Erosion of the overlying clastic Miocene Hawthorn group strata on one flank of a structural arch has exposed the limestone The elevated edge of the Hawthorn cover forms the Cody scarp Ubiquitous solution pipes have previously formed at joint intersections and are now filled Downwashing of the fill deeper into solution cavities in the limestone and subsidence of the overlying unconsolidated sediments causes surface collapse a subsidence doline or sinkhole This process may penetrate up to 60 m of the semi-consolidated Hawthorn cover, as occurred when the Winter Park sinkhole developed Dense clusters of solution pipes may have formed cenotes which are now found on the exposed limestone terrain Groundwater moves laterally as diffuse flow except where input or outflow is concentrated. At sinking streams, vertical shafts, and springs, karst caves have formed, but only the major sinking streams form through-flowing conduit systems Shaft recharge dissipates diffusely. Spring discharge is concentrated from diffuse flow In both cases, conduits taper and merge into a zone of megaporosity

Chemical and Thermal Analysis

NASA Technical Reports Server (NTRS)

Bulluck, J. W.; Rushing, R. A.

1997-01-01

Work during the past three years has included significant research in several areas aimed at further clarification of the aging and chemical failure mechanism of thermoplastics (PVDF or Tefzel) for pipes. Among the areas investigated were the crystallinity changes associated with both the Coflon and Tefzel after various simulated environmental exposures using X-Ray diffraction analysis. We have found that significant changes in polymer crystallinity levels occur as a function of the exposures. These crystallinity changes may have important consequences on the fracture, fatigue, tensile, and chemical resistance of the materials. We have also noted changes in the molecular weight distribution and the increased crosslinking of the Coflon material using Gel Permeation Chromatographic Analysis. Again these changes may result in variations in the mechanical and chemical properties in the material. We conducted numerous analytical studies with methods including X-ray Diffraction, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, and Differential Scanning Calorimetry. We investigated a plethora of aged samples of both Tefzel and Coflon that were forwarded from MERL. Pressurized tests were performed on powdered PVDF in a modified Fluid A, which we will call A-2. In this case the ethylene diamine concentration was increased to 3 percent in methanol. Coflon pipe sections and powdered Coflon were exposed in pressure cells at 1700 psi at three separate test temperatures.

Closed loop oscillating heat pipe as heating device for copper plate

NASA Astrophysics Data System (ADS)

Kamonpet, Patrapon; Sangpen, Waranphop

2017-04-01

In manufacturing parts by molding method, temperature uniformity of the mold holds a very crucial aspect for the quality of the parts. Studies have been carried out in searching for effective method in controlling the mold temperature. Using of heat pipe is one of the many effective ways to control the temperature of the molding area to the right uniform level. Recently, there has been the development of oscillating heat pipe and its application is very promising. The semi-empirical correlation for closed-loop oscillating heat pipe (CLOHP) with the STD of ±30% was used in design of CLOHP in this study. By placing CLOHP in the copper plate at some distance from the plate surface and allow CLOHP to heat the plate up to the set surface temperature, the temperature of the plate was recorded. It is found that CLOHP can be effectively used as a heat source to transfer heat to copper plate with excellent temperature distribution. The STDs of heat rate of all experiments are well in the range of ±30% of the correlation used.

FBG-based sensorized light pipe for robotic intraocular illumination facilitates bimanual retinal microsurgery.

PubMed

Horise, Yuki; He, Xingchi; Gehlbach, Peter; Taylor, Russell; Iordachita, Iulian

2015-01-01

In retinal surgery, microsurgical instruments such as micro forceps, scissors and picks are inserted through the eye wall via sclerotomies. A handheld intraocular light source is typically used to visualize the tools during the procedure. Retinal surgery requires precise and stable tool maneuvers as the surgical targets are micro scale, fragile and critical to function. Retinal surgeons typically control an active surgical tool with one hand and an illumination source with the other. In this paper, we present a "smart" light pipe that enables true bimanual surgery via utilization of an active, robot-assisted source of targeted illumination. The novel sensorized smart light pipe measures the contact force between the sclerotomy and its own shaft, thereby accommodating the motion of the patient's eye. Forces at the point of contact with the sclera are detected by fiber Bragg grating (FBG) sensors on the light pipe. Our calibration and validation results demonstrate reliable measurement of the contact force as well as location of the sclerotomy. Preliminary experiments have been conducted to functionally evaluate robotic intraocular illumination.

Gas-liquid two-phase flow pattern identification by ultrasonic echoes reflected from the inner wall of a pipe

NASA Astrophysics Data System (ADS)

Liang, Fachun; Zheng, Hongfeng; Yu, Hao; Sun, Yuan

2016-03-01

A novel ultrasonic pulse echo method is proposed for flow pattern identification in a horizontal pipe with gas-liquid two-phase flow. A trace of echoes reflected from the pipe’s internal wall rather than the gas-liquid interface is used for flow pattern identification. Experiments were conducted in a horizontal air-water two-phase flow loop. Two ultrasonic transducers with central frequency of 5 MHz were mounted at the top and bottom of the pipe respectively. The experimental results show that the ultrasonic reflection coefficient of the wall-gas interface is much larger than that of the wall-liquid interface due to the large difference in the acoustic impedance of gas and liquid. The stratified flow, annular flow and slug flow can be successfully recognized using the attenuation ratio of the echoes. Compared with the conventional ultrasonic echo measurement method, echoes reflected from the inner surface of a pipe wall are independent of gas-liquid interface fluctuation, sound speed, and gas and liquid superficial velocities, which makes the method presented a promising technique in field practice.

NASA National Combustion Code Simulations

NASA Technical Reports Server (NTRS)

Iannetti, Anthony; Davoudzadeh, Farhad

2001-01-01

A systematic effort is in progress to further validate the National Combustion Code (NCC) that has been developed at NASA Glenn Research Center (GRC) for comprehensive modeling and simulation of aerospace combustion systems. The validation efforts include numerical simulation of the gas-phase combustor experiments conducted at the Center for Turbulence Research (CTR), Stanford University, followed by comparison and evaluation of the computed results with the experimental data. Presently, at GRC, a numerical model of the experimental gaseous combustor is built to simulate the experimental model. The constructed numerical geometry includes the flow development sections for air annulus and fuel pipe, 24 channel air and fuel swirlers, hub, combustor, and tail pipe. Furthermore, a three-dimensional multi-block, multi-grid grid (1.6 million grid points, 3-levels of multi-grid) is generated. Computational simulation of the gaseous combustor flow field operating on methane fuel has started. The computational domain includes the whole flow regime starting from the fuel pipe and the air annulus, through the 12 air and 12 fuel channels, in the combustion region and through the tail pipe.

Performance of fuel system at different diesel temperature

NASA Astrophysics Data System (ADS)

Xu, Xiaoyong; Li, Xiaolu; Sun, Zai

2010-08-01

This paper presents the findings about performance of the fuel system of a diesel engine at different diesel temperature obtained through simulation and experiment. It can be seen from these findings that at the same rotational speed of fuel pump, the initial pressure in the fuel pipe remain unchanged as the fuel temperature increases, the peak pressure at the side of fuel pipe near the injector delays, and its largest value of pressure decreases. Meanwhile, at the same temperature, as the rotational speed increases, the initial pressure of fuel pipe is also essentially the same, the arrival of its peaks delays, and its largest value of pressure increases. The maximum fuel pressure at the side of fuel pipe near the injector has an increase of 28.9 %, 22.3%, and 13.9% respectively than the previous ones according to its conditions. At the same rotational speed, as the temperature increases, the injection quantity through the nozzle orifice decreases. At the same temperature, as the rotational speed increases, the injection quantity through the nozzle orifice increases. These experimental results are consistent with simulation results.

Measurements of terahertz radiation generated using a metallic, corrugated pipe

DOE PAGES

Bane, Karl; Stupakov, Gennady; Antipov, Sergey; ...

2016-11-23

Here, a method for producing narrow-band THz radiation proposes passing an ultra-relativistic beam through a metallic pipe with small periodic corrugations. We present results of a measurement of such an arrangement at Brookhaven's Accelerator Test Facility (ATF). Our pipe was copper and was 5 cm long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a corrugation depth (peak-to-peak) of 60 µm. In the experiment we measured both the effect on the beam of the structure wakefield and the spectral properties of the radiation excited by the beam. We began by injecting a relatively long beam comparedmore » to the wavelength of the radiation, but with short rise time, to excite the structure, and then used a downstream spectrometer to infer the radiation wavelength. This was followed by injecting a shorter bunch, and then using an interferometer (also downstream of the corrugated pipe) to measure the spectrum of the induced THz radiation. For the THz pulse we obtain and compare with calculations: the central frequency, the bandwidth, and the spectral power—compared to a diffraction radiation background signal.« less

Measurements of terahertz radiation generated using a metallic, corrugated pipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bane, Karl; Stupakov, Gennady; Antipov, Sergey

Here, a method for producing narrow-band THz radiation proposes passing an ultra-relativistic beam through a metallic pipe with small periodic corrugations. We present results of a measurement of such an arrangement at Brookhaven's Accelerator Test Facility (ATF). Our pipe was copper and was 5 cm long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a corrugation depth (peak-to-peak) of 60 µm. In the experiment we measured both the effect on the beam of the structure wakefield and the spectral properties of the radiation excited by the beam. We began by injecting a relatively long beam comparedmore » to the wavelength of the radiation, but with short rise time, to excite the structure, and then used a downstream spectrometer to infer the radiation wavelength. This was followed by injecting a shorter bunch, and then using an interferometer (also downstream of the corrugated pipe) to measure the spectrum of the induced THz radiation. For the THz pulse we obtain and compare with calculations: the central frequency, the bandwidth, and the spectral power—compared to a diffraction radiation background signal.« less

Thermocapillary phenomena and performance limitations of a wickless heat pipe in microgravity.

PubMed

Kundan, Akshay; Plawsky, Joel L; Wayner, Peter C; Chao, David F; Sicker, Ronald J; Motil, Brian J; Lorik, Tibor; Chestney, Louis; Eustace, John; Zoldak, John

2015-04-10

A counterintuitive, thermocapillary-induced limit to heat- pipe performance was observed that is not predicted by current thermal-fluid models. Heat pipes operate under a number of physical constraints including the capillary, boiling, sonic, and entrainment limits that fundamentally affect their performance. Temperature gradients near the heated end may be high enough to generate significant Marangoni forces that oppose the return flow of liquid from the cold end. These forces are believed to exacerbate dry out conditions and force the capillary limit to be reached prematurely. Using a combination of image and thermal data from experiments conducted on the International Space Station with a transparent heat pipe, we show that in the presence of significant Marangoni forces, dry out is not the initial mechanism limiting performance, but that the physical cause is exactly the opposite behavior: flooding of the hot end with liquid. The observed effect is a consequence of the competition between capillary and Marangoni-induced forces. The temperature signature of flooding is virtually identical to dry out, making diagnosis difficult without direct visual observation of the vapor-liquid interface.

Parameter Prediction of Hydraulic Fracture for Tight Reservoir Based on Micro-Seismic and History Matching

NASA Astrophysics Data System (ADS)

Zhang, Kai; Ma, Xiaopeng; Li, Yanlai; Wu, Haiyang; Cui, Chenyu; Zhang, Xiaoming; Zhang, Hao; Yao, Jun

Hydraulic fracturing is an important measure for the development of tight reservoirs. In order to describe the distribution of hydraulic fractures, micro-seismic diagnostic was introduced into petroleum fields. Micro-seismic events may reveal important information about static characteristics of hydraulic fracturing. However, this method is limited to reflect the distribution area of the hydraulic fractures and fails to provide specific parameters. Therefore, micro-seismic technology is integrated with history matching to predict the hydraulic fracture parameters in this paper. Micro-seismic source location is used to describe the basic shape of hydraulic fractures. After that, secondary modeling is considered to calibrate the parameters information of hydraulic fractures by using DFM (discrete fracture model) and history matching method. In consideration of fractal feature of hydraulic fracture, fractal fracture network model is established to evaluate this method in numerical experiment. The results clearly show the effectiveness of the proposed approach to estimate the parameters of hydraulic fractures.