1,797 research outputs found
Development of a PIGE-Detection System for In-situ Inspection and Quality Assurance in the Evolution of Fast Rotating Parts in High Temperature Environment Manufactured From TiAl
Intermetallic Ξ³-titanium aluminides are a promising material in high temperature technologies. Their high specific strength at temperatures above 700Β°C offers the possibility for their use as components of aerospace and automotive industries. With a specific weight of 50% of that of the widely used Ni-based superalloys TiAl is very suitable as material for fast rotating parts like turbine blades in aircraft engines and land based power stations or turbocharger rotors. Thus lower mechanical stresses and a reduced fuel consumption and CO2-emission are expected. To overcome the insufficient oxidation protection the halogen effect offers an innovative way. After surface doping using F-implantation or liquid phase-treatment with an F-containing solution and subsequent oxidation at high temperatures the formation of a protective alumina scale can be achieved. By using non-destructive ion beam analyses (PIGE, RBS) F was found at the metal/oxide interface. For analysis of large scale components a new vacuum chamber at the IKF was installed and became operative. With this prototype of in-situ quality assurance system for the F-doping of manufactured parts from TiAl some performance test measurements were done and presented in this paper.Received: 01 March 2013; Revised: 24 April 2013; Accepted: 25 April 201
The measurement of long period and secular deformation with deep borehole tiltmeters
Two clusters of instruments were emplaced in fractured bedrock in eastern Massachusetts in 1970 and 1975. The intrasite agreement at tidal periods was about two percent, but there is no agreement at longer periods. A strong temperature-induced annual component ranging from 3 to 15 urads was present on instruments installed at depths of 15-20m; it was not apparent on those at 100-120m. One instrument, in continuous operation for three years at 100m, showed a net drift of 0.3 urads down to the SW, with a maximum departure of 2.0 urads from the trend. Pore pressure variations, material corrosion and creep, and local movements are apparently the limiting factors to long-term measurements
ANALYSIS OF THE ELECTRICAL CHARACTERISTICS IN MULTIPHASE FLOW THROUGH THE WIRE-MESH SENSOR
Many studies on the characterization of electrical properties of multiphase fluid are found in the literature. One of the main motivations of these efforts has been the development of instrumentation for the measurement of volumetric fraction using electrical sensors. Although one can find a variety of instruments for that purpose, relatively few works in the open literature present studies on the best range of measurement frequency and its effect on permittivity models. An experimental and theoretical study is presented, where the best frequency to measure the volumetric fraction in two and three-phase mixtures is selected. Several permittivity models are applied to measure the volumetric fraction. The fluids used in the experiments were tap water, deionized water, mineral oil, isopropyl alcohol and hexane. Known volumes of fluids were mixed until obtaining a homogeneous mixture. The data were taken by a 1Γ4 wire-mesh sensor (WMS) immersed in the mixture. The WMS had a gap between planes of 1.4 mm, the wires were 3 mm apart from each other and the diameter of the wires was of 0.2 mm. The experimental system consisted of a generator, an oscilloscope and conditioning circuits (formed by operational amplifiers). A frequency scan was performed between 7000 Hz and 20 MHz for each mixture. A total of 60 logarithmically spaced frequencies were applied
Development of a PIGE-Detection System for in-situ Inspection and Quality Assurance in the Evolution of Fast Rotating Parts in High Temperature Environment Manufactured from TiAl
Intermetallic Ξ³-titanium aluminides are a promising material in high temperature technologies. Their high specific strength at temperatures above 700Β°C offers the possibility for their use as components of aerospace and automotive industries. With a specific weight of 50% of that of the widely used Ni-based superalloys TiAl is very suitable as material for fast rotating parts like turbine blades in aircraft engines and land based power stations or turbocharger rotors. Thus lower mechanical stresses and a reduced fuel consumption and CO2-emission are expected. To overcome the insufficient oxidation protection the halogen effect offers an innovative way. After surface doping using F-implantation or liquid phase-treatment with an F-containing solution and subsequent oxidation at high temperatures the formation of a protective alumina scale can be achieved. By using non-destructive ion beam analyses (PIGE, RBS) F was found at the metal/oxide interface. For analysis of large scale components a new vacuum chamber at the IKF was installed and became operative. With this prototype of in-situ quality assurance system for the F-doping of manufactured parts from TiAl some performance test measurements were done and presented in this paper.Received: 01 March 2013; Revised: 24 April 2013; Accepted: 25 April 201
Tidal friction in the solid earth
The earth's imperfectly elastic response to body and loading tidal forces is discussed using complex Love numbers and complex mass loading coefficients. Exact analytical expressions were derived relating the energy dissipation within an inhomogeneous, compressible solid earth to the surface values of these complex characteristic numbers, thus relating the global dissipation function Q to the phase shifts in the potential, gravity, tilt, strain and displacement tides. Integration of a global ocean tidal model shows that energy dissipated in the solid earth due to ocean loading is at least 10% of that dissipated in the body tides
On the stress dependence of the earthquake b value
Laboratory experiments have shown that the b value in the size distribution of acoustic emission events decreases linearly with differential stress. There have been a number of observations that indicate that this relation may also hold for earthquakes. Here using a simple frictional strength model for stresses in the continental lithosphere combined with earthquake b values measured as a function of depth in a wide variety of tectonic regions, we verify and calibrate that relation, finding bβ=β1.23βΒ±β0.06βββ(0.0012βΒ±β0.0003)(Ο1βββΟ3), where the stress difference (Ο1βββΟ3) is in megapascal. For subduction zones, we find that b value correlates linearly with the slab pull force and with the net reduction of plate interface normal force, both of which also indicate a negative linear relation between b value and differential stress
ΠΠ°Π·Π΅ΡΠ½ΠΎΠ΅ ΠΈΠ½ΠΈΡΠΈΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎΡΠΎΡΠΊΠΎΠ² ΡΡΠ½Π° Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ ΠΎΠ±ΡΠ΅ΠΌΠ½ΠΎΠ³ΠΎ ΡΠΆΠ°ΡΠΈΡ
ΠΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ ΡΠ½Π΅ΡΠ³Π΅ΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΠΎΡΠΎΠ³ΠΈ ΠΈΠ½ΠΈΡΠΈΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΈ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π° ΠΊΠΈΠ½Π΅ΡΠΈΠΊΠ° ΠΏΡΠΎΡΠ΅ΡΡΠ° Π²Π·ΡΡΠ²Π½ΠΎΠ³ΠΎ ΡΠ°Π·Π»ΠΎΠΆΠ΅Π½ΠΈΡ ΠΏΠΎΡΠΎΡΠΊΠΎΠ² ΡΠ΅ΡΡΠ°Π½ΠΈΡΡΠ°ΡΠ° ΠΏΠ΅Π½ΡΠ°ΡΡΠΈΡΡΠΈΡΠ°, ΠΎΠ±ΡΠ΅ΠΌΠ½ΠΎΡΠΆΠ°ΡΡΡ
Π΄ΠΎ Π΄Π°Π²Π»Π΅Π½ΠΈΡ 5Β·108Π/ΠΌ2, ΠΏΡΠΈ Π²ΠΎΠ·Π΄Π΅ΠΉΡΡΠ²ΠΈΠΈ ΠΈΠΌΠΏΡΠ»ΡΡΠΎΠΌ Π»Π°Π·Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ Π½Π° Π΄Π»ΠΈΠ½Π°Ρ
Π²ΠΎΠ»Π½ 1064 Π½ΠΌ (ΠΎΠ±Π»Π°ΡΡΡ ΠΏΡΠΎΠ·ΡΠ°ΡΠ½ΠΎΡΡΠΈ) ΠΈ 266 Π½ΠΌ (ΠΎΠ±Π»Π°ΡΡΡ ΡΠΎΠ±ΡΡΠ²Π΅Π½Π½ΠΎΠ³ΠΎ ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ). Π Π΅Π°Π»ΠΈΠ·ΠΎΠ²Π°Π½Ρ ΡΡΠ»ΠΎΠ²ΠΈΡ Π½ΠΈΠ·ΠΊΠΎΠΏΠΎΡΠΎΠ³ΠΎΠ²ΠΎΠ³ΠΎ ΠΈΠ½ΠΈΡΠΈΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄Π»Ρ ΠΏΠΎΡΠΎΡΠΊΠΎΠ² ΡΠΈΡΡΠΎΠ³ΠΎ ΡΡΠ½Π° ΠΏΠ΅ΡΠ²ΠΎΠΉ, Π²ΡΠΎΡΠΎΠΉ ΠΈ ΡΠ΅ΡΠ²Π΅ΡΡΠΎΠΉ Π³Π°ΡΠΌΠΎΠ½ΠΈΠΊΠ°Ρ
ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ Π½Π΅ΠΎΠ΄ΠΈΠΌΠΎΠ²ΠΎΠ³ΠΎ Π»Π°Π·Π΅ΡΠ°
Reply to 'A Second Opinion on "Operational Earthquake Forecasting: Some Thoughts on Why and How," by Thomas H. Jordan and Lucile M. Jones,' by Stuart Crampin
In folklore, a "silver bullet" is an effective weapon against were-wolves and witches. In earthquake prediction, a silver bullet is a diagnostic precursorβa signal observed before an earthquake that indicates with high probability the location, time, and magnitude of the impending event (Jordan 2006). In his comment, Crampin (2010) claims that shear-wave splitting (SWS) observations provide a silver bullet. He asserts that seismology is thus capable of raising earthquake forecasting out of the low-probability environment to which we assigned it in our recent opinion piece (Jordan and Jones 2010)
High Energy Benthic Boundary Layer Experiment (HEBBLE): Preliminary program plan and conceptual design
Deep sea processes of flow-sediment interaction, particularly the role of high energy ocean bottom current events in forming the seafloor topography, transporting material, and mixing the bottom of the water column are examined. A series of observations at and near the sea bottom, in water depths of 4 to 5 km, in areas of the western North Atlantic where high energy current events occur, include site surveys and physical reconnaissance to identify suitable areas and positions, and one or more six month experiments to investigate temporal and spatial variations of high energy events within the boundary layer and their interaction with the seabed. Descriptions of proposed HEBBLE activities are included, with emphasis on technology transfer to the oceanographic community through design, fabrication, testing, and operation of an instrumented ocean bottom lander
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