Showing papers on "Transverse plane published in 1977"

A combined normal‐ and transverse‐displacement interferometer with an application to impact of y‐cut quartz

Abstract: A new transverse‐displacement inteferometer (TDI) is described. This interferometer makes use of intensity variations of a beam obtained by superposition of two beams diffracted symmetrically from a diffraction grating copied onto a plane surface. The TDI is used to monitor the transverse motion of the rear surface of a y‐cut quartz target plate in a plate‐impact experiment. For this application, a 200‐line/mm grating is copied onto the rear surface of the target plate. The normal motion of the rear surface is monitored by means of a standard Michelson interferometer in which the zeroth‐order diffracted beam is used as the beam reflected from the moving mirror. The transverse motion is monitored simultaneously by means of a TDI employing the two fourth‐order diffracted beams, with a resulting sensitivity of 0.625 μm per fringe. The recorded motion confirms the predicted features of two coupled elastic waves, each involving both normal and transverse motion.

Patient positioning indication arrangement for a computed tomography system

Abstract: A computed tomography system has an arrangement for indicating the staged position of a patient in relation to the location of a first scan by the system. The arrangement includes at least one energy beam source, such as a laser, which projects a visible pattern on the surface of the patient. The pattern corresponds to the central alignment of the system and to the location of the first scan of the system when a patient-supporting table is subsequently translated into a gantry of the system for x-ray examination. The pattern includes a central longitudinal line indicating a central longitudinal plane of the area to be scanned, and a transverse line indicating the location of the transverse plane of the first scan. The energy beam source of the arrangement is adjustable to project an angled line which corresponds to a tilted gantry or a tilted patient, or a tilted supporting table to indicate the location of the transverse plane of the first scan of the system. The patient is aligned and located in agreement to the projected patterns to thereby properly position the patient for the subsequent desired first scan by the system.

Nonlinearity in power‐output–current characteristics of stripe‐geometry injection lasers

Abstract: The origins and behaviors of kinks in power‐output–injection‐current (I‐L) curves of stripe‐geometry lasers are theoretically investigated. Laser output power is calculated as a function of injection current by solving the carrier diffusion equation and Maxwell’s equation. Transverse modes along the junction plane are assumed to be guided by the injected‐carrier‐induced gain profile. At low current densities, it is shown that the gain profile is nearly parabolic, resulting in the transverse mode very close to the lowest Hermite‐Gaussian distribution. However at high current densities the gain profile is deformed by the stimulated recombination of carriers near the center of the stripe. The resultant mode becomes deformed and penetrates into the low‐gain or lossy region. Consequently the mode gain is reduced, and the power saturation (kink) appears in the I‐L curves. If there exists an asymmetry in the injection current density profile, it is shown that the optical intensity peak moves along the junction plane and the beam direction shifts from the normal to the laser facets with the increase of the current density. Such theoretical results are qualitatively in good agreement with recent experimental observations and demonstrate that kinks originate from the gain profile deformation and the resultant mode deformation. Investigating the dependence of the output power at which a kink appears on various device parameters such as the stripe width, the amount of current spreading, and the degree of asymmetry, we conclude that the scatter of the output power experimentally observed is caused by the small fluctuations of such device parameters.

Longitudinal and transverse displacements of a bounded microwave beam at total internal reflection

Abstract: Longitudinal and transverse shifts of an 8 cm parallel bounded beam of 34.2 GHz (8.77 mm) microwaves totally reflected from a paraffin prism have been investigated. The 45°–45°–90° prism is 18 cm high by 25 cm on the sides and the index of refraction is 1.491. Longitudinal shifts as large as 3 cm have been measured in a single reflection near the critical angle for a beam linearly polarized in the plane of incidence. The shift for perpendicular polarization is approximately half this value. The results are in general agreement with the classical theory for the Goos-Hanchen effect. An incident beam polarized at 45° to the incidence plane produces both parallel and perpendicular polarization shifts with values similar to the above. The shifts for both polarizations are reduced but are still distinctly separate if either a second prism or a metallic reflector is brought into the evanescent wave at millimeter distances from the interface. These results are in accordance with stationary phase calculations for two interfaces. It is found that a small (6 mm) transverse shift results if the prism is illuminated with circularly polarized microwaves.

Magnetic recording device for double sided media

Abstract: In a data storage system using a non-rigid magnetic storage surface, such as a floppy disc, and in which recording and reproduction are to be effected on both sides of the element by contact transducers, significant improvements over prior art devices are realized by employing a fixed transducer on one side of the element, and a movable transducer element on the opposite side. The movable transducer may be gimbal mounted on a pivoted spring-loaded arm of low mass and high stiffness to urge the magnetic storage surface against the fixed transducer with a light force. The force is adequate, together with a slight penetration of the fixed transducer into the plane of the disc, to correct deflections of the storage surface in directions transverse to its principal plane in the region between the transducers. Thus the transducers are maintained in operative relation for maximum flux interchange, but without introducing undue wear or requiring a long head settling time.

Electrodynamics at Metal Boundaries with Inclusion of Plasma Waves

Abstract: The energy theorem of electrodynamics is cast in a form which yields expressions for the energy current and energy dissipation of a combined field of transverse and longitudinal waves when the longitudinal field is described in the hydrodynamic approximation. This has consequences concerning the boundary conditions for transverse and plasma waves at metal-metal interface and the photoemission yield.

Ballistics of Transversely Impacted Fibers

Abstract: The rate-independent theory of transverse impact of textile fibers is reviewed and cast in a form that provides convenient preliminary guidance to designers of impact-resistant textile structures. It is shown that energy-absorption rate increases monotonically with fiber modulus, but that decreased ductility at high modulus may result in an optimum fiber stiffness for transverse critical velocity. A reaction-rate fraction model is suggested as a means of rationalizing the observed variation in experimental transverse critical velocities.

Moving‐load stability of a circular plate on a floating central collar

Abstract: The eigenvalue problem and transverse response of a circular plate, that is free at the periphery and that slides freely along the axis of symmetry without bending rotation, are theoretically analyzed. The occurance of eigenvalues in the boundary conditions is accounted for with an extended operator definition in the equation of transverse motion. The stability of these plates under concentrated loads moving at uniform speed is analyzed for (i) harmonic transverse loading and (ii) loading proportional to transverse displacement and velocity. The harmonic loading case leads to a classical, critical‐speed analysis. The proportional loading case represents the excitation of the plate by transverse position guides. The number, orientation, and mechanical properties of the guides determine the transverse stability of the plate‐guide dynamic system.

Method of measuring stress in a material

Abstract: Stress in a material is measured using electromagnetically generated, transverse elastic waves. A correlation is known to exist between the difference in velocity of orthogonally polarized transverse waves in the type material being measured and stress in the material. An electromagnetic transducer is used to generate orthogonally polarized waves traveling through the part at different velocities as a result of anisotropic stress in the part. The difference in velocity between the polarized waves is measured and compared to the correlation to obtain the stress existing in the part.

Method and apparatus for severing tubing

Abstract: Apparatus for severing tubing along a generally transverse plane through the tubing wall, and including two confined explosive charges aligned axially with the tubing wall and terminating at opposed, proximal ends facing each other across a space disposed in such transverse plane. A portion of the opposed ends of the charges can contact each other, provided the main bodies of the two charges are spaced at the location of the plane of desired severance. Detonation devices are disposed at the distal or remote ends of the charges for originating detonation of the charges at such distal ends. The apparatus is employed by emplacing the confined charges in the tubing to be severed with the charges positioned on opposite sides of, and terminating with their proximal ends substantially at, the plane in which the desired severance is to be effected. The charges are then simultaneously exploded by concurrently initiating the explosion of each at points substantially equidistantly spaced from the desired plane of severance.

Method and apparatus for palletizing articles

Abstract: Method and apparatus for palletizing articles delivered by an accumulator belt onto a pallet in transverse rows of alternating orientation, with the first and last transverse rows of each tier of articles on the pallet being of the same orientation, such palletization being accomplished by engaging and lifting the transverse row of an appropriate orientation which immediately follows the last transverse row of a first tier, loading a second tier of articles with the transverse row immediately following the lifted transverse row forming the first transverse row of such tier, reforming the lifted transverse row into a transverse row of the appropriate orientation by side shifting, and inserting the reformed lifted transverse row as the initial transverse row of a third tier of articles.

Unstable horizontal transverse modes and their stabilization with a new stripe structure

Abstract: Kinks in the light output and other anomalous characteristics in stripe-geometry lasers were studied. It was found that these anomalies were caused by unstable horizontal, parallel to the junction, transverse modes. Introduction of a refractive-index guiding by Zn-diffusion stabilized the horizontal mode and removed the kink and other anomalies completely.

Gas velocity meter

Abstract: A flow velocity meter is described suitable for measuring the mean flow velocity of a medium flowing along a duct using optical means which generates first and second beams of light each in the form of a relatively shallow wide band which traverse the duct across first and second spaced apart transverse planes which are arranged substantially at right angles to the mean flow direction. Light beams emerging from the duct are received on respective photoelectric detectors the output signals of which are essentially identical but relatively displaced because of the time required for the medium to flow between the two planes. By processing the signals in a correlation circuit this time is established and is used to produce an output proportional to the mean flow velocity of the medium between the two planes. The correlation circuit used is based on digital techniques.

The ventricular size on computed tomography.

Abstract: Deriving a ventriculocranial index for the evaluation of ventricular size from a standard transverse plane image can lead to an erroneously small estimate of ventricular size due to partial volume averaging. Coronal plane imaging largely eliminates this problem. The index can then be derived either from the video image or the digital printout. There appears to be less error in measurements derived from the image than in measurements derived from the 64 X 64 printout, provided the image is photographed at large window widths of 2,000 Delta units or more.

Transverse dielectric response of a semi-infinite metal: Surface effect

Abstract: The transverse dielectric response of a semi-infinite solid is studied in terms of the current-current correlation function. An expression is given for the conductivity tensor as a generalization of the corresponding bulk formula, when translational invariance normal to the surface is absent, but translational invariance parallel to the surface is retained. The $f$-sum rule is generalized and then used to establish the gauge invariance of the result for conductivity. The transverse conductivity is nonlocal and anisotropic even in the long-wavelength limit owing to the presence of the surface. Specific surface features that influence the result are isolated and studied in a simple, convenient manner. The importance of including finite electronic lifetime effects is emphasized.

Investigations on the self-loosening of threaded fasteners under transverse vibration

Abstract: This paper presents a solution for self-loosening mechanism of bolt-nut joints under transverse vibration. At the first stage of relative transverse displacement between fastened plates, a bolt-thread inclines in a mating nut-thread with slip on the screw-surface of the nut-thread, producing elastic torsion of the bolt-shank. At the next stage of the transverse displacement, the washer face of the nut slips on the surface of the vibrating plate, accompanying loosening rotation of the nut caused by spring back of the elastic torsion of the bolt-shank. Repetition of these behaviours in each cycle of the vibration, advances the self-loosening of the bolt-nut joint. Above mentioned self-loosening mechanism is analyzed theoretically, considering loci of slip on the screw surface and washer face. The theory is compared with the experiment, resulting that they show fairly good agreement, except small difference which is seemed to be caused by the fluctuation of the frictional coefficients on the screw surface and the washer face.

An explanation of the observed differences between coronal holes and quiet coronal regions

Abstract: The main differences between a coronal hole and quiet coronal regions are explained by a reduction of the thermal conduction coefficient by transverse components of the magnetic field in the transition region of quiet coronal regions

Longitudinal and transverse field losses in multifilament superconductors

Abstract: A review is given of the method of calculating losses in a composite twisted multifilament superconductor based on the anisotropic continuum model, and a summary of results are shown for the loss as a function of frequency due to longitudinal and transverse applied fields. In both cases three frequency ranges may be distinguished in which (1) the magnetic field in the superconductor is just the applied field, (2) the field produced by internal currents becomes important, and (3) skin effect develops in the eddy currents, which flow transverse to the filaments. In addition to these losses in the body of the superconductor (characterized by a vanishing component of electric field parallel to the filament axes), the loss in the current saturated boundary layer is described. Some discussion is also given on the use of ac field losses in calculating the "ramped" field case.

Metal carrier for trim

Abstract: A metal carrier is embedded into trim, for providing proper rigidness in the transverse direction as well as in the longitudinal direction to the strip-like trim formed with rubber or plastics and the like. Transverse slots are formed in the strip-like sheet metal at given intervals in the longitudinal direction and a thin link portion and/or narrow width portion (sectional area in the transverse direction is small) is alternately formed at the top and bottom portions of the transverse slot. When an external force is applied to the metal carrier covered with rubber or plastics, the formed connecting links of the thin link portion and/or narrow width portion at top and bottom are broken, and the metal carrier becomes a continuous zigzag strip.

Optical web inspection system

Abstract: The specification discloses an optical web inspection system for detecting imperfections in a web having a longitudinal axis and moving in a plane across an inspection area. Radiation means is disposed above the plane of the web and transverse to the longitudinal axis of the web for directing radiant energy on the web at the inspection area. A plurality of sensors are mounted transverse to the longitudinal axis of the web and above the inspection area for receiving reflected radiation from successive transverse portions of the web passing across the inspection area. The plurality of sensors generate electrical output signals representing the intensity of the reflected radiation from the successive transverse portions of the web. Circuitry for periodically summing the electrical output signals from selected ones of the sensors is provided to generate a summation signal representative of the sum of reflected radiation from selected discrete segments of a plurality of the transverse portions of the web. The system further includes circuitry for comparing at least one of the electrical output signals with the summation signal for determining whether an imperfection exists within the web.

Broadband microwave polarizer device

Abstract: A broadband microwave polarizer device for introducing a differential phase shift between orthogonal components of linear orthogonally-polarized signals, the differential phase shift being relatively constant over a wide range of frequencies, for example, a range of frequencies of 5.925GHz to 6.425GHz. The polarizer device includes a section of waveguide having two opposing rows of pins at inner surface regions thereof, in a first common plane, and two opposing ridges at other inner surface regions thereof in a second common plane transverse to the first plane. By appropriate design of the pins and ridges, a relatively constant resultant phase shift φ R may be achieved over the abovementioned bandwidth. The value of φ R may be approximated by A.sub.O -B.sub.O +(A.sub.1 -B.sub.1)(f-f.sub.O) + (A.sub.2 -B 2 )(f-f O ) 2 , where f is a selected frequency of the orthogonally-polarized signals, f is the center frequency of the operating frequency bandwidth of the polarizer device, A O , A 1 and A 2 , are constants associated with the two rows of pins of the polarizer device, and B O , B 1 and B 2 are constants associated with the two ridges of the polarizer device.

The E.M.I. scanner.

Abstract: The E.M.I. scanner is a machine which employs a method of X-raying patients whereby the information obtained from the X-rays is fully utilized. The high sensitivity thus obtained enables the machine to differentiate between the various organs of the body which are presented in three-dimensional form as a series of tomographic slices. The machine scans through the patient in a transaxial plane with a narrow beam of X-rays. A bank of detectors measures the transmission through the body as it scans across the plane and this is repeated at many different angles through the plane. The readings obtained from the detectors are passed to a computer which mathematically reconstructs a picture of absorption values of the slice.

Transverse effects associated with the propagation of coherent optical pulses in resonant media

Abstract: Analytical and numerical methods are used to study the transverse reshaping that occurs when ultrashort optical pulses propagate through media resonant to the pulse-carrier frequency. The field is described by the scalar quasi-optic equation, and the material system by the full Bloch equations describing a distribution of homogeneously broadened two-level molecules. Transverse derivatives in the field equation provide the coupling leading to the development of radially dependent frequency variations and phase curvature. We have studied the origin and evolution of transverse energy flow and investigated the conditions under which this leads to significant coherent self-focusing. The physical mechanisms responsible for the onset and development of the focusing phenomenon are discussed and related to other types of self-confinement of optical pulses.

Device for locating a layer of tubes in an enclosure

Abstract: A layer of tubes is located in an enclosure using a device comprising a pair of parallel strips arranged one on each side of the layer of tubes in a plane transverse to the axes of the tubes, the strips being connected together by tongues which extend from a respective strip towards the other strip, the tongues being inclined to the strips and adjacent tongues of each strip being inclined in opposite directions.