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The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O

Over the last two years, concern has been generated about the capabilities of performing nondestructive evaluation (NDE) of the closure-head penetrations in nuclear-reactor pressure vessels. These penetrations are primarily for instrumentation and control rod drive mechanisms (CRDMs) and are usually thick-walled Inconel tubes, which are shrink-fttted into the steel closure head. The penetrations are then welded between the outside surface of the penetration and the inside surface of the closure head. Stress corrosion cracks initiating at the inner surface of the penetration have been reported at several plants. Through-wall cracks in the CRDM penetration or CRDM weld could lead to loss of coolant in the reactor vessel. The CRDM penetration presents a complex inspection geometry for conventional NDE techniques. A thermal sleeve, through which pass the mechanical linkages for operating the control rods, is inserted into the penetration in such a way that only a small annulus (nominally 3 mm) exists between the thermal sleeve and inside surface of the penetration. Ultrasonic (UT) and eddy current testing (ET) techniques that could be used to provide defect detection and sizing capability were investigated. NDE techniques that could be applied inside and outside the annulus were investigated, but the major goal was to provide high defect-detection sensitivity without requiring removal of the thermal sleeve. As a result of this investigation, both ET and UT techniques for the CRDM penetrations have been developed and evaluated. Long, thin probes were designed to fit into the annulus to carry both eddy current coils and irrigated ultrasonic transducers into the region of interest. The eddy current probes were used primarily to detect cracks in the penetration while the ultrasonic transducers were used to provide an estimate of the remaining wall thickness. This paper describes the ET and UT techniques, the probes developed, and the results obtained using these probes and techniques on CRDM penetration mock-ups.

The small-scale roughness of the sea surface acts as an important link in air-sea interaction processes. Radar and sonar waves are scattered by short surface waves providing the basis for remote sensing methods of the sea surface. At high wind speeds, breaking waves occur. Bubbles penetrate into the water and drastically increase acoustical reverberation, transmission loss and ambient noise. Thus, the development of short waves and wave breaking have to be known to apply radar remote sensing to the surface and to deduce from radar backscatter which sonar conditions prevail. To measure the wind dependence of short waves an experimental device was constructed for use from stationary platforms. It is nearly all-weather capable and can easily be handled by a crane. On the other hand, frequencies of short waves measured in a fixed position are extremely frequency shifted by currents. This limits the usefulness of tower-based measurements, e.g., the short wave modulation by wind and waves or currents can only be estimated in a rough approximation. Consequently, a buoy was developed to reduce the frequency shifts. The principle of the buoy is to drift in the local surface current and to follow the amplitudes of long waves. Therefore, short waves are measured in facets of long waves and the Doppler shifts are minimized. The wind is measured at a constant height above the long wave profile and relative to the moving facets. The paper describes the conventional measuring device and points out the necessity of the drifting buoy system. Examples of wind and wave spectra are presented and short wave modulations by long waves are depicted, too. From these measurements, new insights in short wave behaviour have to be expected. >

Sonar and radar signals are scattered by small-scale roughness elements of the sea surface. The characteristics of the roughness depend on wind, sea state, and other parameters. The dynamic behavior of this roughness is related to radar backscatter. This provides a basis for oceanographic radar remote sensing and links radar backscatter to sea surface sonar conditions. Radar, sonar, and roughness experiments have been conducted at the research platform NORDSEE. The results are combined and provide a method to estimate shallow water sonar conditions from the radar backscatter cross section. >

A narrowband tunable eXtreme UltraViolet (XUV) laser source is used for a high resolution study of the Lyman (B 1 Σ + ™X 1 Σ + ) band system of molecular hydrogen. Seven rotational transitions of two vibrational bands, (10,0) and (11,0), in the wavelength range from 97.2–98.3 nm have been investigated for the first time under sub-Doppler molecular beam conditions. A calibration procedure using the I2 standard in the visible yielded an absolute frequency accuracy of 0.02 cm−1. The obtained H2 transition frequencies provide a calibration standard in the extreme ultraviolet wavelength region.

An experimental method to investigate submarine bedform signatures at the sea surface is described. The study area was the Lister Tief in the German Bight of the southeastern North Sea, a semienclosed tidal basin with asymmetric and very large sand waves. In-situ and remote measurements of surface roughness were obtained simultaneously. An X-band wave monitoring radar, an oceanographic multisensor sea surface buoy, an acoustic Doppler current profiler, and a standard echo sounder were operated on and from board a research vessel while drifting along the tidal channel. >

The intrinsic photostability of 3-phenyl-1,2-dihyrdonaphthalene ( 4a ) in hexane at room temperature was proved by photoacoustic measurements. The large photoacoustic effect of 4a compared with that of 2-phenylindene ( 7 and stilbene ( 8 demonstrates the unexpected flexible structure of excited 4 .

The temporal coherence between atmospheric turbulence 5 meters above the mean sea surface and the small scale roughness, was measured by four different microwave radar wavelengths during the SAXON-FPN experiment. Continuous radar cross section measurements (one second averages) and spatially coincident, simultaneous sonic anemometer measurements of the 3 wind components provide the first known coherence function for frequencies from .0005 to .5 Hz. Unexpectedly, the wind fluctuations above .01 Hz do not induce correlated surface roughness variations, as observed by L,S,X and Ka-band radars. Only below .01 Hz, and only for X-band and Ka-band roughness scales do the authors measure coherences above 0.5. These results indicate that the short waves are only correlated with the wind on scales of 10's of minutes. Therefore the authors cannot assume that these short sea waves receive their energy directly from the wind, and they must identify a wave generating mechanism for these centimeter waves based on hydrodynamic interactions. >

Measurements of short waves are often performed using resistance wire systems in fixed positions. They have the serious disadvantage that measurements in frequency space are Doppler-shifted. Corrections are only possible in coarse approximation and often not feasible. To reduce these shifts high frequency wave profilers have to drift in local currents. During the SAXON-experiment measurements were performed with a fixed device and with a new developed drift buoy. Results of wave and breaker measurements are presented. Examples of short wave spectra show different characteristics when Doppler-shifts are reduced.

Gastrointestinal graft-versus-host disease (GVHD) is one of the main causes of therapy-related death after allogeneic hemopoietic stem cell transplantation. Early diagnosis and immediate treatment are probably essential for improving clinical outcome. High-resolution sonography allows the evaluation of single bowel wall layers throughout the small and large bowel. We report the sonographic findings of seven consecutive patients with histologically confirmed GVHD grade II–IV of the gastrointestinal tract. The patients were examined sonographically within the 1st week after onset of clinical symptoms. Dilatation of the colon and striking bowel wall thickening were early and common features in these patients. Sonography may become a useful tool for diagnosis of patients with gastrointestinal GVHD. Its role for preclinical diagnosis, grading of severity of disease, and guiding therapy of patients with gastrointestinal GVHD warrants evaluation in prospective studies.

Radar images often show features of bottom topography although radar waves do not penetrate the water. This imaging process is caused by bottom induced current variations which modulate the short waves and hence the radar backscatter intensity. Principally it is possible to deduce a transfer function from radar images to bottom topography. In the frame of the C-STAR project of the European Commission (Coastal Sediment Transport Assessment using SAR imagery) a field experiment had been performed to study the short wave modulation due to bottom topography. A special buoy system drifted across the study area off the Dutch coast measuring waves, wind and bottom profiles. The results clearly show correlations of short wave modulation and water depths.

Radar signatures of spatially varying surface currents, such as found over underwater bottom topography in tidal waters, are often underestimated by theoretical models. After the development of advanced radar backscattering models which account for contributions of the entire ocean wave spectrum, this is usually attributed to shortcomings of existing wave-current interaction theories. In this paper we discuss results of a comprehensive analysis of radar images and in-situ wave and wind data that were acquired during the C-STAR experiment over underwater bottom topography in the North Sea. As expected, measured radar signatures and intensity variations of short waves are underestimated by a conventional model. Clear improvement is obtained after introducing a modified equilibrium wave spectrum and spatial wind stress variations as given by buoy data. Our results suggest that a surface roughness-wind stress feedback mechanism exists, which leads to a coupling between intensity variations of short ripple waves and longer waves via interaction with the wind field.

The knowledge of the imaging mechanisms of submarine bedforms based on the functional dependence of the interaction between the current and water surface roughness on meteorological, oceanographic, and radar parameters was improved during recently conducted experiments. Within the framework of the Marine Science and Technology Program (MAST-I) during 1990-1992 of the Commission of the European Communities a group of several institutes in Europe has investigated the mapping of sea bottom topography in a multi-sensor approach for morphodynamic studies off the Dutch coast. During the SAR and X-Band Ocean Nonlinearities Research Platform North Sea (SAXON-FPN) Experiment in 1990 one aim was to improve the understanding of the hydrodynamics due to the sea bed. Within this project oceanographic, meteorological and remotely sensed shipborne radar data of a nonlinear flow regime were simultaneously observed and analysed. The maximum radar cross-section modulation caused by the sand waves in the MAST-I study area is about 3 dB and is located at the downstream end of the steep slope. A strong current-wave interaction creates the roughness modulation in the SAXON-FPN study area. >

The concept of the modulation transfer function between the microwave backscatter from meter-sized areas of the sea surface and the long dominant-wave slope is being expanded to include the role of wind fluctuations at the surface. In the experimental results from the SAXON-FPN experiment, X-band radar measurements have been supplemented by simultaneous wind measurements performed by an ultrasonic anemometer positioned 5 meters above the surface. This study is to examine the correlation between the low frequency wind fluctuations and the sizeable low frequency signal in the corresponding radar spectrum that has long been observed but not yet explained. The results of the joint radar and wind data analysis show coherences between the atmospheric turbulence and the RCS fluctuations. In the frequency range where the ocean wave spectrum is dominant (>0.1 Hz) the coherence function for the atmospheric turbulence displays a minor, but still visible role. In the frequency range below 0.01 Hz, the authors find the highest consistent coherences. This finding implies that the 2 cm Bragg waves at a given location appears to be less affected by the local instantaneous wind and stress; it is only correlated with the wind on scales of 10's of minutes. >

Measurements of short sea waves are often conducted by resistance wire methods. Instruments installed in fixed positions provide frequencies which are Doppler-shifted by tidal and orbital currents, also by wind induced surface drifts. In the case of cm-waves these shifts go up to several hundred per cent. To study short wave dynamics in detail, e.g., the modulation by long waves, the shifts must be excluded by the measuring method. A buoy has been developed which follows the long wave amplitudes and the local currents. Short waves are measured at greatly reduced Doppler-shifts and the wind is measured in constant height above the long wave profile. Examples of wave and wind spectra and short wave-long wave correlations are presented. Short wave modulation depths are depicted, too. >

Radar signals are scattered by short scale roughness elements of the sea surface. These features depend on wind, sea state and other parameters. The dynamical behaviour of this roughness provides the basis of oceanographic radar remote sensing. Sonar signals are also scattered by short waves causing reverberation. Wave breaking and bubble production give rise to transmission loss, reverberation, and ambient noise. Breaker measurements have been conducted on board the research platform NORDSEE. Characteristic signal jumps were recorded by a resistance wire measuring device. Signal analyses and wave approximations resulted in estimates of breaker heights, lengths and momenta. Breakers produce bubbles. Their penetration depths were measured by a towed side scan sonar fish. Statistical relations of bubble penetration depths were deduced. >

Pharmacists are becoming increasingly involved in the detection and monitoring of chronic disease states. A growing number of chronic diseases can be screened and monitored by pharmacists, including diabetes, dyslipidemias, hypertension, and osteoporosis. Devices for screening and monitoring are becoming less complex and more convenient, allowing for greater use in pharmacies and, in many cases, for patients use at home. The provision of pharmacist-led assessment services is becoming more widely accepted by patients, physicians, and some third-party payers.

Detection of subsurface cracks around fasteners and hidden corrosion in multi-layer aluminum structure is a critical requirement for aging aircraft inspection. Of particular concern is the Navy P-3 aircraft which is currently undergoing refurbishment In this aircraft, multi-layer structure with thicknesses up to 0.3 inch must be inspected nondestructively to identify areas in need of repair. In order to meet productivity requirements, eddy current testing (ECT) using the McDonnell Douglas MAUS III system will be performed.

Es gibt — entsprechend der Indikation — verschiedene Formen der Vorbehandlung von Blutkonserven. Zur Sensibilisierungsprophylaxe fur haufig transfusionsbedurftige Patienten werden beispielsweise Erythrozytenkonzentrate eingesetzt, deren Leukozytengehalt man zuvor durch Sedimentation und mechanische Trennung oder auch durch Filterung stark reduziert hat. Mehrmaliges Waschen von Erythrozytenkonzentraten vor einer Transfusion ist bei Patienten mit Antikorpern gegen Plasmaproteine, z. B. im Rahmen eines IgA-Mangels, indiziert. Auf die Bestrahlung von Blutkonserven mit Gammastrahlen wird im folgenden naher eingegangen. Auch wenn die Indikation zur Bestrahlung nur selten gegeben ist, ist die Kenntnis hieruber von Bedeutung, um schwerwiegende Komplikationen zu vermeiden.

Current techniques for determination of the thickness of coatings for gas turbine parts involve metallographic measurements on sections cut from the coated component. This technique is time consuming and expensive, and only a limited amount of data can be obtained for individual systems. In this paper, initial results are presented for a nondestructive technique using eddy current testing. Measurements have been carried out on flat and curved surfaces with and without thermal barrier coatings, and good agreement has been obtained with metallographic determinations in every case. Preliminary data suggest that a combination of eddy current and ultrasonic techniques may enable degradation behavior to be monitored.

Hexapole state-selection and orientation of parent molecules is combined with two-dimensional ion imaging of photofragments to study the direct photolysis of deuterated methyl iodide molecules (CD3I). These two techniques allow us to create an essentially single quantum state-selected beam of oriented molecules, which are subsequently photodissociated, and to measure the final state-, velocity-, and angle-resolved recoil distribution of fragments. For the prompt dissociation of CD3I at 266 nm the angular recoil distribution reflects predominantly the initial spatial orientation of the state-selected parent. The dependence of the orientation of the parent as a function of the orientation fieldstrength has been investigated and the three-dimensional recoil distributions of fragments are compared with theoretically calculated distributions.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We use a combination of hexapole focusing and two‐dimensional ion imaging to study the direct photolysis of methyl iodide molecules. Hexapole focusing allows us to select the (JKM) rotational state and orient the molecule before it is photolyzed. Resonance enhanced multiphoton ionization (REMPI) of the products of the photolysis and two‐dimensional imaging of the ions give us the internal energy and angular distribution of the fragments. Next to reporting results obtained with the photolysis of methyl iodide molecules we would like to discuss some future objects of study. Dissociation of linear triatomic molecules like BrCN, N2O and OCS results in rotationally highly excited diatomic fragments. The dynamics on the anisotropic excited state potentials can be revealed into much greater detail with oriented parents as compared to the conventional studies with isotropic parents. © 1995 American Institute of Physics

Sub-Doppler excitation spectra of HD have been recorded in the range 92--98 nm with the use of a narrow-band and tunable extreme ultraviolet laser in combination with a molecular beam. Frequencies of 147 transitions to the {ital B} {sup 1}{Sigma}{sub {ital u}}{sup +}, {ital C} {sup 1}{Pi}{sub {ital u}}, and {ital EF} {sup 1}{Sigma}{sub {ital g}}{sup +} states have been calibrated with an average absolute accuracy of 0.035 cm{sup {minus}1}. The data have been analyzed in the framework of a semiempirical deperturbation model involving mutual couplings between nearby lying levels of the {ital B} {sup 1}{Sigma}{sub {ital u}}{sup +} and {ital C} {sup 1}{Pi}{sub {ital u}} states. Also, symmetry-breaking effects, i.e., interactions with {ital EF} {sup 1}{Sigma}{sub {ital g}}{sup +} gerade states, were inferred from the data.

IR photo-dissociation spectra of SF6 clusters have been studied. A He-seeded molecular beam has been attenuated by crossing it with a line tunable cw CO2 laser of moderate power. — In the electron bombardment beam ionizer (E el=100eV) small neutral clusters are found to fragment predominantly to the main monomer mass (SF 5 + ). — Predissociation spectra have been calculated for clusters containing up to six SF6-molecules invoking the dipole-dipole resonance force to lift the degeneracy of the molecule — excited molecule interaction. On the basis of these spectra, dimer and trimer concentrations have been determined quantitatively, for different molecular beam conditions.

A beam of state-selected NO molecules (J = Ω = 3 2 ) has been produced by an electrostatic hexapole and has been collided with O3 molecules in a scattering chamber. The E-field dependence of the chemiluminescent cross section, σhr, has been investigated and resulted in the determination of the M-dependence of σhr: σhr (M)/σ0 = 1.192±0.009, 0.0848±0.015, 1.177±0.015, 0.783±0.009 for M = 3 2 , 1 2 , −1 2 and −3 2 , respectively. Application of the Legendre expansion technique and the density matrix formalism provided a deconvoluted σhr(γ), for a single angle of attack γ of the NO axis, expressed in simple model functions with adjustable parameters. From this analysis it is concluded that chemiluminescence only occurs when cos γ ≈ 1, the “end-on-head” orientation of NO yielding ≈ 30% of all collected light, and when cos γ ≈ −0.275, the “broad-side-tail” orientation of NO yielding the remaining 70%. The steric factors belonging to these reactive orientations have been estimated and are S1 = 0.25±0.07 and S2 = 0.40±0.09, respectively. The observed dependence of σhr has been confronted with the rules of Woodward and Hoffman. Although there are indeed two symmetries (bpl and cpl) correlating the electron orbitals of the reactants and the products, these rules do not lead to an explanation of the steric effects of the NO+O3 reaction.

For the first time, in-situ measurements of orbital velocities were obtained 5 cm above the sea bed in a wave boundary layer by hot wire anemometry. For a wind speed of 12 knots, the period of the peak of the wind-sea spectrum shifted from 3.3 sec at the surface to 4.8 sec at the bottom in a water depth of 15 m. The maximum horizontal bottom velocity μ 1m did not exceed 1.5 cm/sec. The possible influence of specific features of the selected site on wind sea and on bottom roughness is discussed in a comparison of measured data with predictions by linear-wave theory.

The influence of internal (rotational and electronic fine structure states of NO) and translational energy upon the chemicaluminescence has been studied by crossing a seeded NO beam with an effusive O3 beam for energies large in comparison with threshold. The translational energy (0.4< Etr< 1.6 eV) is selected by a velocity selector placed in front of the scattering region. Thus, the internal beam temperature (state distribution) remains constant, when Etr is varied by changing the rotational frequency of the velocity selector. The cross section of this exothermic process is found to increase very rapidly with translation, νhν ∝ E3.75tr, with some levelling off starting at Etr ≈ 1.2 eV. The influence of the internal energy of the NO-molecules is studied by changing the pressure behind the nozzle, at a constant speed of the velocity selector; thereby the internal beam temperature is varied (100 ⩽ T| ⩽ 300 K). A linear behaviour is found: σhν ∝ [1+α(kT|/Ethreshold)] with Ethreshold=0.129 eV and α = 4.5 ± 0.5 for Etr between 0.62 and 0.84 eV. Assuming the rotational and electronic fine structure temperature equal to T|. we obtain (dohν/dĒt)/(dσhν/dĒtr) = 4.5 ± 0.5 at Etr = 0.7 eV with Ēint = Ērot + Ēel· Eint is even more efficient than Etr in promoting chemiluminescence in the visible. If the internal energy effect can be attributed ot different cross sections for the two fine structure states involved, one derives σhν(Π12)/σhν(Π32) = 0.27 ± 0.03. The exothermic chemiluminescent reaction cross section is surprisingly energy selective far from the threshold.

Dimers can often be treated as prolate symmetric tops, with their symmetry axis along the dimer axis. In that case, thermal excitation results in J, MJ ⪢ K if the moment of inertia around the dimer axis can be assumed much larger than the moment of inertia along an axis perpendicular to it. Expressions are derived which describe the near saturation behaviour of perpendicular and parallel excitations; for J, MJ ⪢ K, simple analytical expressions are obtained.

Three independent sources of information are used to analyze the angle dependent potential for NOAr: (a) the glory structure of the total collision cross section; (b) the relative difference in the total collision cross section for two different orientations of NO in the 2Π 3 2 state; (c) the absolute value of the total collision cross section. The sudden approximation employed for the calculation of the various properties is discussed. For NOAr a fit to the total collision cross section data is obtained on the basis of an extended Maitland—Smith potential containing a Pt anisotropy in the repulsion and a P2 anisotropy in the repulsion and attraction. A comparison is made with the theoretical potential for NOAr recently by Nielson et al. and the extended Lennard-Jones potential employed in the earlier analysis. For NOKr and NOXe similar Maitland—Smith potentials are obtained by assuming the Pt anisotropy parameter for these systems to be equal to that for NOAr. In a separate appendix is analyzed which intermolecular distances are probed through measurements of the anisotropy in the total collision cross section.

IR predissociation spectra for C2H4 dimers have been recorded, using a cw CO2 laser as source of radiation and a Ge bolometer as detector. Apart from the main peak around 952 cm−1, two extra peaks at 916 and 986.3 cm−1 have been observed. Those two peaks are discussed in terms of van der Waals combination modes and, from their relative intensities, dimer temperatures in He-seeded beams have been obtained. Observed peaks show rotational fine structure with a 10 MHz linewidth, which implies a predissociation lifetime of 16 ns.

The IR absorption spectra of gaseous CF3Br expanded in a molecular jet have been recorded with a linewidth of about 0.002 cm−1. The rotational K-structure of the ν1 fundamental has been resolved and the molecular constants ΔB and ΔA have been determined with an accuracy better than 5 x 10−6 cm−1. Spectral features belonging to the ν6- and ν3-hotbands have been identified. For CF3B79r (CF3B81r) improved values of the vibrational origins for the fundamental ν1 = 1084.768(2) cm−1 (1084.520(2) cm−1) and for its hotbands ν3+ν1←ν3 = 1081.709(80) cm−1 (1081.065(40) cm−1) and ν6+ν1←ν6 = 1083.533(4) cm-1 (1083.288(4) cm-1) have been determined.

Molecular beam electric resonance spectrsocopy has been used to investigate the Δ J = 0, Δ M = ± 1 transition of the 1 11 , 2 11 , 4 04 and 4 13 rotational states of ozine in the presence of external electric and magnetic fiels. The data have been used to evaluate the electric dipole moment μ = 0.53373 (7) D; the electric polarizability anisotropies α aa −α = 2.04(40) A 3 and α bb −α = −0.98(13) A 3 ; the molecular g -values g aa = −2.9877(9), g bb = −0.2295(3) and g cc = −0.0760(3); and the magnetic susceptibility anisotropies (in units of 10 −6 erg/G 2 mole) x aa − x = 23.85(11) and x bb − x = 0.41(8). The molecular quadrupole moments obtained from the g -values and the magnetic susceptibility anisotropies are in satisfactory agreement with the results of ab initio calculations. The bulk susceptibility of ozone is estimated to be x = 8.0 × 10 −6 erg/G 2 mole, using the theoretical value of the out-of-plane component of the second moment of the electronic charge distribution.