Mass scan

Applications of Silicon Carbide. SiHcon carbides are used more for the low temperature wear properties than for the high temperature behavior. AppHcations such as sand blasting nozzles, automotive water pump seals, bearings, pump components, and extmsion dies utilize the high hardness, abrasion resistance, and corrosion resistance of siHcon carbide (4,5,32). Elevated temperature stmctural appHcations range from rocket nozzle throats to furnace roUers and the combination of high thermal conductivity and high temperature strength and stabiHty make siHcon carbide heat exchanger tubes and diffusion furnace components feasible.  [c.321]

Refractories. Its low coefficient of expansion, high thermal conductivity, and general chemical and physical stabihty make sihcon carbide a valuable material for refractory use. Suitable apphcations for sihcon carbide refractory shapes include boiler furnace walls, checker bricks, mufflers, kiln furniture, furnace skid rails, trays for zinc purification plants, etc (see Refractories).  [c.468]

The mass scan mode is used to survey the entire mass spectrum within a certain volume of the specimen.  [c.537]

Mass Scan Mode  [c.539]

A mass scan is acquired in cases when a survey of all impurities present in a volume of material is needed. Rather than measuring the secondary ion count rates of preselected elements as a fimction of sputtering time the count rates of all secondary ions are measured as a fimction of mass. Because a mass scan is continuously acquired over a mass range, no depth profiling or lateral information is available while operating in this mode. Figure 4 shows a mass scan acquired from a zirconia  [c.539]

Figure 4 Mass scan acquired from a zirconia crystai. Figure 4 Mass scan acquired from a zirconia crystai.
By contrast, in the system propionic acid d) - methyl isobutyl ketone (2), (fi and are very much different when y 1, Propionic acid has a strong tendency to dimerize with itself and only a weak tendency to dimerize with ketone also,the ketone has only a weak tendency to dimerize with itself. At acid-rich compositions, therefore, many acid molecules have dimerized but most ketone molecules are monomers. Acid-acid dimerization lowers the fugacity of acid and thus is well below unity. Because of acid-acid dimerization, the true mole fraction of ketone is signi-  [c.35]

In the first class, azeotropic distillation, the extraneous mass-separating agent is relatively volatile and is known as an entrainer. This entrainer forms either a low-boiling binary azeotrope with one of the keys or, more often, a ternary azeotrope containing both keys. The latter kind of operation is feasible only if condensation of the overhead vapor results in two liquid phases, one of which contains the bulk of one of the key components and the other contains the bulk of the entrainer. A t3q)ical scheme is shown in Fig. 3.10. The mixture (A -I- B) is fed to the column, and relatively pure A is taken from the column bottoms. A ternary azeotrope distilled overhead is condensed and separated into two liquid layers in the decanter. One layer contains a mixture of A -I- entrainer which is returned as reflux. The other layer contains relatively pure B. If the B layer contains a significant amount of entrainer, then this layer may need to be fed to an additional column to separate and recycle the entrainer and produce pure B.  [c.81]

Now let us take a closer look at the two most commonly used heat engines (steam and gas turbines) to see whether they achieve this efficiency in practice. To make a quantitative assessment of any combined heat and power scheme, the grand composite curve should be used and the heat engine exhaust treated like any other utility.  [c.194]

This brief description of past and present refining developments leads to a certain number of important remarks. First of all, we are observing a gradual, continuous evolution. It could hardly be otherwise, considering the large time factors —it takes several years to build a refinery— the capital investment, and the tightness of the product specifications. Moreover, refining evolves around successive modifications to a basic flow scheme containing a limited number of processes. These processes have been greatly improved over the past twenty years from the technological point of view and, for catalytic processes, the level of performance of the catalysts in service. On the other hand, very few new processes have appeared as early as 1970 one could almost have built the refinery of the year 2000 but with much lower performance with regard to energy, economics, and product quality. Among the truly new processes, one can name selective oligomerization, light olefin etherification and very low pressure reforming with continuous catalyst regeneration.  [c.485]

For example a process flow scheme for crude oil stabilisation might contain details of equipment, lines, valves, controls and mass and heat balance information where appropriate. This would be the typical level of detail used in the project definition and preliminary design phase described in Section 12.0.  [c.239]

In such cases the development scheme for the original reserves may have to be modified to make processing capacity available for the new hydrocarbons. The economics of such a scheme can be affected negatively if substantial engineering modifications have to made to meet new safety legislation. For more background to ERD refer to Section 3.  [c.364]

Three different specimens are considered here. Penetration depths range from 0.7 mm for aluminium to 0.15 mm for the steel block. For the experimental test frequencies used the electromagnetic skin depth is much smaller than the depth of the cracks for all the measurement considered.  [c.143]

Ultrasonic waves are generated by a Q-switched Nd Yag laser operating at the wavelength of 1.064 /xm with a half-width pulse duration of 15 ns, while a Mach-Zehnder heterodyne interferometer is used for the detection of ultrasound (Fig. 1). The probe, with a large bandwidth 20 kHz - 30 MHz, only measures the out-of-plane displacements with a sensitivity of about 10 run/ /Hz on a mirror-like surface [2]. The laser beam is focused on the surface of the sample by a spherical or a cylindrical lens to form a circular spot or a line source, respectively. The optical power density is adjusted to avoid any damage ensuring a non-destructive testing (thermoelastic regime). Mechanical displacements drive the movement of the sample according to two directions, which is, as the data processing, entirely controlled by computer. The ultrasonic images are visualized (B-scan views) thanks to the softwares developed by our laboratory.  [c.694]

The prototype of verification system of ultrasonic flaw detector developed is described in the scheme given in figure 2. The verification operators performed with the system are as much automated as possible. The level of automatization is limited by the necessity of human reading of information on flaw detector screen, or other operations as manual adjustment of flaw detector settings.  [c.703]

MUSE with HILL-SCAN 3010)  [c.860]

After magnetizing the disk it is placed on a turntable to support and move it during measurements. Fig. 3 shows an example measurement of the remanent magnetization of artifical inclusions with masses of 1 mg, 10 mg, and 15 mg at a depth of 70 mm. The signal to noise ratio is very high. A test which is nearer to the resolution limit is shown in fig. 4. An iron particle with a mass of approximately 10 mg was magnetized and than placed 4 mm below the sensor, i. e. the bottom of the cryostat containing the SQUIDs. The single scan signal to noise ratio is still much larger than 10. Averaging will give further improvments.  [c.989]

What is the critical surface tension for human skin Look up any necessary data and make a Zisman plot of contact angle on skin versus surface tension of water-alcohol mixtures. (Note Ref. 136.)  [c.381]

The interest in vesicles as models for cell biomembranes has led to much work on the interactions within and between lipid layers. The primary contributions to vesicle stability and curvature include those familiar to us already, the electrostatic interactions between charged head groups (Chapter V) and the van der Waals interaction between layers (Chapter VI). An additional force due to thermal fluctuations in membranes produces a steric repulsion between membranes known as the Helfrich or undulation interaction. This force has been quantified by Sackmann and co-workers using reflection interference contrast microscopy to monitor vesicles weakly adhering to a solid substrate [78]. Membrane fluctuation forces may influence the interactions between proteins embedded in them [79]. Finally, in balance with these forces, bending elasticity helps determine shape transitions [80], interactions between inclusions [81], aggregation of membrane junctions [82], and unbinding of pinched membranes [83]. Specific interactions between membrane embedded receptors add an additional complication to biomembrane behavior. These have been stud-  [c.549]

Atomic force microscopy yields magnifications and atomic resolution maps rather similar to those obtained by STM. There are two useful differences, however. AFM works with nonconducting surfaces, while STM requires conducting or semiconducting surfaces. Further, in AFM one can scan at constant force, and the force chosen can be varied. Scans at different force levels may show differences since projecting surface atoms may be pushed inward to varying degrees depending on the force level (e.g.. Ref. 25). Both STM and AFM may be used at a solid-liquid interface, but more often the latter. An example shown in Fig. XVIII-3 is that of DNA at the mica-water interface.  [c.688]

A complementary approach to reaction dynamics centres on probing reaction products by optical spectroscopy. Optical spectroscopy often provides higher resolution on the product internal energy distribution than the measurement of translational energy distributions, but is less universally applicable than mass spectrometry as a detection scheme. If products are fonned in electronically excited states, their emission spectra (electronic chemiluminescence) can be observed, but ground-state products are more problematic. Polanyi [24] made a seminal contribution in this field by showing that vibrationally excited products in their ground electronic state could be detected by spectrally resolving their spontaneous emission in the infrared this method of infrared chemiluminescence has proved of great utility in detennining product vibrational and, less frequently, rotational distributions.  [c.873]

Equation (A3.11.85) implies that the R, r —> S, s transfomiation is orthogonal, a point which is responsible for the similarities between the Hamiltonian expressed in tenns of reagent and product mass-scaled coordinates ((A3.11.81) and (A3.11.84)). In fact, the reagent to product transfomiation can be thought of as a rotation by an angle p followed by a flip in the sign of. s. The angle p is sometimes called the skew angle, and it can vary between 0 and 90°, as detennined by equation (A3.11.86). If (i.e., all three  [c.975]

Recently, it has been shown that both the detection and generation of ultrafast THz pulses can be carried out usmg the electro-optic effect in thin films of materials such as ZnTe, GaAs and InP that are pumped in the near-IR [49]. The generation efficiency is similar to that of the photoconducting anteima approach, but the electro-optic scheme offers two extremely significant advantages. First, the detection bandwidth can be extremely large, up to 30-40 THz under optimum conditions [49]. Second, it is possible to directly image the THz field with such spectrometers. Such approaches therefore make possible the THz imaging of optically opaque materials with a compact, all solid-state, room-temperature system [50]  [c.1249]

Based o the test data, the parameter a6 is correlating with the residual resistance (table 1). It is discovered that the less resistible samples have much higher value of a6. On the base of collected data it is possible to identify the critical value of the accumulation coefficient (which is a defective sign of the material (if aG> AiScR-the sample is defected if aG< a6cr - the sample is without defects).  [c.84]

TRIFOU is a general code for solving Maxwell s equations. It has been developed by EDF/R D for ten years. TRIFOU is able to treat different electromagnetic problems such as magnetostatic, magnetodynamic (transient or harmonic regime), electrostatic and micro wave. It is able to treat the thin-skin regime by reducing mesh step size in the test block depth direction.  [c.140]

TRIFOU can model any isotropic material encountered in eddy current inspections such as ferromagnetic steel and aluminium. TRIFOU can model any type of probe with one or several coils, including those containing ferrite cores and shields. For the thin-skin regime modelling, basic rules are needed for accurate results. The ratio between the mapped mesh step and the penetration depth in the test block has to be small enough to ensure good precision in the results. But too many elements increase the calculation time and the memory space needed, so that a compromise has to be made. For the following calculations the ratio between mesh step and penetration depth is greater than 3. This hypothesis is to be validated.  [c.141]

The HILL-SCAN 30XX boards can be used in different PCs. Desktop- and tower-PCs as well suited for laboratory uses. For in-field inspections rugged notebooks and portable PCs are advantageous. A typical portable system is shown in Fig. 2 (USPC 3010), used in MUSE (Mobile Ultrasonic Equipment). This portable PC not only contains the boards for ultrasonic testing but also a controller with power supply for stepper motors, so that a manipulator can be connected directly. The MUSE system is enlarged with a water circulation system which enables a local immersion technique" for in-field inspections. A typical result is shown in Fig. 3, which presents a D-scan of a CFRP- component in RTM-techniques. The defect area caused by an impact is clearly indicated. The manipulator is described in [3].  [c.859]

Together with LM Glasfiber, FORCE Institute has now developed two new scariners one for inspection of filament winded beams, and one for inspection of bonded joints on rotor blades. The main goal of the project was to develop automated ultrasonic inspection equipment which can be applied on damaged rotor blades, new designs and for production inspection. The two scanners, both controlled by the P-scan system, have been tested with promising results on rotor blades with both artificially and naturally introduced defects such as delaminations, inclusions, missing adhesion, lack of adhesive, porosities and variations in thickness. The newly developed scanners make it possible to scan large bonded areas in a fast and systematic way. The scanners are controlled by the P-scan system, which automatically gives access to a wide range of inspection parameters including a unique visualisation of inspection results.  [c.983]

An eddy-current inspection falls neatly into the client /server paradigm in that the test-piece, probe, defect and instrument circuitry worldview, shown in Figures 1, 2, 3 and 4, can be thought of as the server. The eddy-current instrument display worldview, shown on the right of Figures 1 and 4, can be thought of as the clienl. The client receives or requests information from the server. One process is a producer of information, the other is a consumer. The server can synchronously provide data to clients on the same machine or on any machine connected to the machine. Scan sampling speeds are much slower than modern communication speeds, so that sampled data can be view synchronously at remote sites. This sort of remote synchronous inspection is already being carried out in difficult and remote sites like offshore platforms.  [c.1018]

One of the most novel uses of STM has been to monitor the dynamics of surface processes including phase transitions, surface diffusion, epitaxial growth and corrosion. An example of this type of work is shown in Fig. VIII-2A, where the selective dissolution of Ag from an Ag-Au alloy is studied over a period of 42 min [22]. Corrosion first roughens the surface followed by vacancy migration to form smooth terraces. Similar surface motion is observed in electrochemically roughened gold films [23] and in gold deposited from vapor on mica at sufficient temperatures [20]. In a related application, scanning electrochemical microscopy (SECM), the STM tip serves as an ultramicroelectrode to reduce electroactive species, allowing the study of electrochemical reactions on the 100-nm scale [40]. A novel atom-tracking technique has allowed the direct measurement of Si dimers on Si(OOl) [2S].  [c.295]

Two models for adhesive joint failure are the following. One is essentially a classic, mechanical picture, relating stored elastic energy and the work of crack propagation, known as the Griffith-Irwin criterion (see Ref. 110). Bik-erman [111], however, has argued that the actual situation is usually one of a weak boundary layer. This was thought to be a thin layer (but of greater than molecular dimensions) of altered material whose mechanical strength was less than that of either bulk phase. While oxides, contamination, and so on, could constitute a weak boundary layer, it was also possible that this layer could be structurally altered but pure material. Interestingly, Schonhom and Ryan [112] found that proper cleaning of a plastic greatly improved the ability to bond it to metal substrates. Good ([113], but see Ref. 110 also) has argued that the molecular interface may often be the weakest layer and that adhesive failure is at the true interface. A rather different idea, especially applicable to the peel test procedure, is due to Deijaguin (see Ref. 114). The peeling of a joint can produce static charging (sometimes visible as a glow or flashing of light), and much of the work may be due to the electrical work of, in effect, separating the plates of a charged condenser.  [c.456]

Weak interactions are not invariant to the operation C just as tliey are not invariant to the inversion operation P. One might hope to preserve the exact mirror synnnetry of nature if invariance to the product CP were a fact. Unfortunately, CP synnnetry is not universal [18], although its violation is a small effect that has never been observed outside the neutral Aimeson (kaon) system and the extent of its violation caimot be calculated (unlike the situation with parity violation, which by comparison is a big effect). CP violation pennits unequal treatment of particles and antiparticles and it may be responsible for the domination of matter over antimatter in the universe [19]. Very recent considerations concerning CP violation are summarized in [20] in particular, this reference points out that the study of CP violation in neutral B mesons will probe the physics behind the standard model, which does not predict sufficient CP violation to account, by itself, for the predominance of matter over antimatter in the universe. In the light of the fact that C was introduced as a generalization of the changing-the-sign-of-the-charge operation, it is appropriate that CP violation provides an unambiguous convention-free definition of positive charge it is the charge carried by the lepton preferentially produced in the decay of the long-lived neutral K meson[2 ]. Although CP violation is a fact there is one invariance in nature involving C that is believed to be universal (based on quantum field theory) and that is invariance under the triple operation TCP, which also involves the time reversal operation T.T CP synnnetry implies that every particle has the same mass and lifetime as its antiparticle. However, now, if J C P symmetry is true the observation of CP violation in experiments on neutral K mesons must mean that there is a compensating violation of time reversal synnnetry at the same time. A direct experimental measure of the violation of time reversal synnnetry has not been made, mainly because the degree of violation is very small.  [c.177]

RDOs is much smaller than that for the vibration itself, not to mention that for the near-IR FT-Raman teclmique already discussed. This is particularly striking for high energy modes such as the C-H vibrations [108]. Modem applications of I CRS now utilize a two-dimensional time-frequency detection scheme  [c.1209]

Fourier transfomr ion cyclotron resonance (FT-ICR) mass spectrometry is another in the class of trapping mass spectrometers and, as such is related to the quadnipole ion trap. The progenitor of FT-ICR, the ICR mass spectrometer, originated just after the Second World War when tire cyclotron accelerator was developed into a means for selectively detecting ions other than protons. At the heart of ICR is the presence of a magnetic field that confines ions into orbital trajectories about their flight axis. Early ICR experiments mainly took advantage of this trapping and were focnsed on ion-molecnle reactions. The addition of the tlnee-dimensional trapping cell by Mclver m 1970 [4T, 42] led to improved storage of ions. In 1974 Comisarow and Marshall introdnced the Former transfonn detection scheme that paved the way for FT-ICR [43, 44] which is now employed in virtually all areas in physical chemistry and chemical physics that rise mass spectrometry.  [c.1355]

As seen in equation B 1.13.2 and equation B 1.13.3. the cross-relaxation rate Ojg is given by W -W , the difference between two transition probabilities. Assuming the simple isotropic rotational iflfiision model, each of the transition probabilities is proportional to a Lorentzian spectral density (cf equation B 1.13.121. taken at tire frequency of the corresponding transition. For the homonuclear case, W2 corresponds to a transition at high frequency (coj+(aj,)=i2(Dj, while is proportional to a Lorentzian at (coj-(Dj,)=iO. When the product is small, is larger than and the cross-relaxation rate is positive. When the product (OjT is large, the Lorentzian fiinction evaluated at 2oj is much smaller than at zero-frequency and Ojj, changes sign. The corresponding NOESY peak intensities m a two-spin  [c.1511]

See pages that mention the term Mass scan : [c.427]    [c.542]    [c.309]    [c.95]    [c.348]    [c.141]    [c.181]    [c.272]    [c.892]    [c.981]    [c.1040]    [c.405]    [c.1296]    [c.1475]    [c.1548]   
Encyclopedia of materials characterization (1992) -- [ c.537 ]