Papers by Darold Wobschall
<title>Parallel hardware architecture for CCD-mosaic digital mammography</title>
Proceedings of SPIE, Jun 26, 1998
ABSTRACT
A Capacitance Meter for Bilayer Membrane Studies
Review of Scientific Instruments, Nov 1, 1972
A meter which features direct readout of the capacitance of artificial lipid bilayer membranes is... more A meter which features direct readout of the capacitance of artificial lipid bilayer membranes is described. It is basically an ac ohmmeter that has been designed to minimize the commonly encountered series (solution) and input resistance errors. An accuracy of about 3% can be achieved for typical membrane capacitances of 10−3−10−1 μF.
Design of teds writer, reader and testing system for transducer interface modules based on the ieee 1451 standard
Dissertations & Theses @ SUNY Buffalo,ProQuest Dissertations & Theses Global, 2006
The commercial benefit of transducer industry is very large potentially. The IEEE 1451 standard p... more The commercial benefit of transducer industry is very large potentially. The IEEE 1451 standard provides compatibility among the products from different transducer manufacturers. The IEEE and NIST developed this standard for smart transducers. In this thesis, I focus on developing IEEE 1451 TEDS Writer/Compiler, TEDS Reader and TIM Tester, etc. and study the following topics: (1) IEEE 1451 TEDS Writer/Compiler and TEDS Reader Design, each with the following seven function blocks: (a) Meta TEDS Writer (Access Code 1); (b) eta ID TEDS Writer (Access Code 2); (c) Transducer Channel TEDS Writer (Access Code 3); (d) Channel ID TEDS Writer (Access Code 4); (e) Calibration TEDS Writer (Access Code 5); (f) Calibration ID TEDS Writer (Access Code 6); (g) XdrcName TEDS Writer (Access Code 12); (2) IEEE 1451 TEDS (Version 1997) Testing system based on the board of NCAP/Ethernet With TCP/IP Through RS232; (3) Design of TIM Tester based on IEEE 1451 Standard; (4) Sensor Data Calibration. Analysis is provided on these topics and a test TIM with three channels is designed for testing purpose of this standard. The TEDS Writer, TEDS Reader and TIM Tester contribute originally to transducer industry field.
The Velocity and Attenuation of Sound in Carbons
Elsevier eBooks, 1960
A study was made of the velocity and attenuation of high frequency longitudinal sound waves trans... more A study was made of the velocity and attenuation of high frequency longitudinal sound waves transmitted through carbon rods. The velocities found are independent of frequency and are in fair agreement with values calculated using values for Young's modulus obtained from static deflections. A rather strong dependence of ultrasonic attenuation on particle size and on heat-treatment temperature was found. Rods made from small particle size mixes show a linear dependence of attenuation on frequency. Hysteresis losses are probably responsible for most of the attenuation in this type of carbon. Rods made of large, single-sized particle mixes have high attenuation coefficients with a square frequency dependence in the frequency range used. This is attributed to scattering of sound waves by pores.
Scope and limitations of thermal imaging using multiwavelength infrared detection
Optical Engineering, 1992
... Scope and limitations of thermal imaging using multiwavelength infrared detection (Journal Pa... more ... Scope and limitations of thermal imaging using multiwavelength infrared detection (Journal Paper). Author(s): Shahram Hejazi; Darold C. Wobschall; Robert A. Spangler MD; Michael Anbar. ... The complete Field Guide to Geometrical Optics is now available as an iPhone app. ...
Step conductance increases in bilayer membranes induced by antibody-antigen-complement action
Biochimica Et Biophysica Acta - Biomembranes, Dec 1, 1975
A sharp rise in the electrical conductance of lipid bilayer membranes was observed following the ... more A sharp rise in the electrical conductance of lipid bilayer membranes was observed following the addition of antigen (bovine serum), antibody (rabbit anti-bovine serum), and complement to the neighboring aqueous phases. At low concentrations, step increases in the conductivity occurred which are consistent with the appearance of about 2.2 nm holes in the membrane. Probably attack or lysis of the lipid bilayer by complement is responsible.
Development and Field Evaluation of Protoype Soil Moisture Sensors
NCHRP Research Results Digest, Jun 1, 1980
This paper discusses a study where moisture determinations from nuclear magnetic resonance (NMR) ... more This paper discusses a study where moisture determinations from nuclear magnetic resonance (NMR) and dielectric sensors were compared with moisture measurements obtained by nuclear depth probes and gravimetric analysis of soil borings. The following are general observations and conclusions of the field evaluation phase of the study: some operational problems were encountered with several sensors of each type; with suitable calibration, both sensors are capable of determining in situ moisture content with an estimated accuracy of 2 percent; although the actual moisture levels encountered in the field were only in the 20 to 30 percent range, on the base of the results of laboratory tests, the actual operating range of the sensors is estimated to be 0 to 50 percent; best results are obtained by calibrating the sensors using the soils of interest; special installation procedures devised for the sensors produce minimal disturbance of the subgrade soil; laboratory studies of temperature effects showed that the dielectric sensor can be used to determine with a high degree of certainty when freezing of pore fluid occurs; and on the basis of current fabrication costs, the price to the user for production quantities is estimated to be $125 per sensor, $1,000 for the dielectric readout, and $5,000 for the NMR readout. The results of this research indicate that both the dielectric and the NMR measurement systems can be potentially useful for in situ determination of moisture in pavement subgrades; and with proper calibration, the accuracy of moisture measurement with these sensors can be at least comparable to existing in situ sensor types such as moisture blocks.
<title>Effect of the reconstruction technique on the quality of digital mosaic mammograms</title>
Proceedings of SPIE, Apr 21, 1998
ABSTRACT
<title>Cost-effective, high-resolution, portable digital x-ray imager</title>
Proceedings of SPIE, May 8, 1995
ABSTRACT
<title>Portable digital radiographic imager: an overview</title>
Proceedings of SPIE, Apr 11, 1996
Pre-production prototype of a low-cost, portable, compact digital radiographic imaging device whi... more Pre-production prototype of a low-cost, portable, compact digital radiographic imaging device which replaces current film based systems has been constructed and tested. Currently, it is in the process of full utilization for field hospitals where immediate verification of the results is essential. For the particular pre-production unit, image acquisition is performed by a 3 by 4 matrix of charge-coupled-device (CCD)
<title>Integrated distortion correction and reconstruction technique for digital mosaic mammography</title>
Proceedings of SPIE, May 7, 1997
ABSTRACT Investigations in the area of digital mammography have been limited by the resolution of... more ABSTRACT Investigations in the area of digital mammography have been limited by the resolution of the sensor devices employed. We have proposed a multiple camera or mosaic architecture in which adjacent sensors observe an overlapping field of view. Such a technique can deliver extremely high resolution while simultaneously maintaining a moderate cost for the resultant instrument. However, this technique&#39;s clinical efficacy will be limited by the ability to accurately and precisely reconstruct a single continuous image from multiple CCD sensors. We present an integrated algorithm which will correct distortions introduced by the camera while addressing the problem of image reconstruction or &#39;re- stitching.&#39; Such a technique will minimize pixel loss by limiting image re-sampling to a single incident. Custom designed calibration screens were employed for the calculation of camera distortion and intra-camera disparity. A parallel digital signal processor architecture has been developed to accelerate system performance when employing a large number of camera inputs. We present a quantitative evaluation of our reconstruction technique and an analysis with respect to similar methods of image reconstruction. We have previously constructed and presented a prototype imager for digital radiography based upon a similar sensor architecture. The algorithm presented will significantly enhance the feasibility of our multiple camera architecture for both digital radiography and mammography. We believe that such a methodology will enhance diagnostic accuracy at a moderate cost when compared with system of similar imaging resolution.
Electronic Properties of Steroid - Iodine Charge Transfer Complexes
PhDT, 1966
Elastic Constants and Permanent Set in Carbons and Graphite at Room Temperature
Elsevier eBooks, 1960
Four basic types of carbons were prepared, namely from (1) soft filler-soft binder, (2) soft fill... more Four basic types of carbons were prepared, namely from (1) soft filler-soft binder, (2) soft filler-hard binder, (3) hard filler-soft binder and (4) hard filler-hard binder. The room temperature elastic constants and permanent set for these types of carbons were measured as a function of heat-treatment temperature. A sensitive apparatus using linear variable differential transformers was developed for measuring elastic moduli in bending and torsion in which the specimen can be stressed in either of two opposite directions. It was found that the dependence of Young's modulus and rigidity modulus on heat-treatment temperature are similar. Hysteresis loops are observed in both force-deflection and torque-twist measurements; the second and third loops becoming progressively more narrow. Annealing the specimen at 1000°C for a few minutes was found to restore the virgin behavior. Crackling noises are detected when carbon specimens are strained for the first time beyond the limits of previous deflection. Room temperature creep was observed which depends logarithmically on time, showing the absence of viscous creep.
Preliminary Studies of Young's Modulus of Carbons at High Temperature
An apparatus has been constructed for measuring the static Young's modulus of carbons in bend... more An apparatus has been constructed for measuring the static Young's modulus of carbons in bending at high temperature. The specimen is heated in a graphite tube furnace and its deflection under load is determined by measuring the deflection at three points with Linear Variable Differential Transformers and appropriate electronic circuits. The force-deflection curves are recorded on an X–Y recorder. Four basic types of carbons were measured, namely, those prepared from (1) soft filler–soft binder, (2) soft filler–hard binder, (3) hard filler–soft binder, and (4) hard filler–hard binder. The usual maximum at about 1800°C was observed for graphitized soft filler bodies; bodies with hard filler showed only a continuous decrease in modulus with increase of temperature. A system of temperature curves was obtained for soft filler–soft binder and for hard filler–hard binder rods as they were heat treated to successively higher temperatures. All the Young's modulus curves show maxima shifting in position with heat treatment except for the graphitized hard filler material.
Progress Report No. 6 for January 1, 1959 to March 31, 1959
ABSTRACT
Progress Report No. 4 for July 1, 1958 to September 30, 1958
Measurement of Young's modulus was made on a graphite 1/2-in.-diam. rod ; for eight differen... more Measurement of Young's modulus was made on a graphite 1/2-in.-diam. rod ; for eight different directions of bending. Additional attenuation measurements ; were made on carbon rods. An effort was made to determine the cause of variance ; of the thermal conductivity as evidenced upon repeated heating and cooling of the ; carbon test specimens. (W.L.H.);
Progress Report No. 2 for September 1, 1957 to November 30, 1957
ABSTRACT
Investigation of Elastic and Thermal Properties of Carbon-Base Bodies
Families of curves of the dependence of Young&#x27;s modulus on temperature ; and on heat tre... more Families of curves of the dependence of Young&#x27;s modulus on temperature ; and on heat treatment were obtained for four basic types of carbons, using high ; temperature equipment. The decisive influence of filler type was established. ; As a result of gained experience, improvements in the associated electronics were ; introduced. The amplitude dependence of the internal friction and dynamic ; Young&#x27;s modulus were, for the first time, investigated at room temperature for ; vibrations in the sonic range of frequencies for several types of carbons. ; Reproducibility was achieved in measurements of thermal conductivity with the new ; high temperature test apparatus and families of curves of the dependence of the ; conductivity on temperature and on heat treatment obtained for soft carbon. A ; new technique of determining the heat conductivity of carbons without internal ; heat generation was tried and found to work up to 1800 deg C. Improved results ; were obtained with the transient state technique of determination of the heat ; diffusivity by using a new fast responding pyrometer and a new improved apparatus ; for the steady sinusoidal wave technique constructed. (auth);
Sensitive Output Indicator for Differential Transformer Displacement Determinations
Review of Scientific Instruments, 1961
A transistorized circuit particularly designed as an output indicator for linear variable differe... more A transistorized circuit particularly designed as an output indicator for linear variable differential transformers is given. It is relatively simple to construct, adjust, and operate. The advantages of a phase-sensitive detector for the measurements of small displacements is discussed. Resolution of the unit is about 0.05 μ; the linearity is about ¼%.
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Papers by Darold Wobschall