What Yer Can\u27t Get Yer Got to do Without / music by John F. Rourke; words by N.D. Mc Donnell

Cover: drawing of a smiling face of an African American male; Publisher: Henry Crey Music Co. (Boston)https://egrove.olemiss.edu/sharris_b/1072/thumbnail.jp

Development and Performance of a Digital Image Radiometer for Heliostat Evaluation at Solar One

A review is presented of the development, performance, and operation of a digital image radiometer (DIR) used to evaluate and enhance heliostat optical and tracking performance at the Solar One 10 MWe pilot plant at Daggett, Calif. The system, termed the beam characterization system (BCS), is based on digitizing, calibrating, and computer-processing video images of heliostat-reflected beams displayed on four 30-by 40-ft targets located on the tower beneath the receiver. Additionally, the radiance distribution of the sun is simultaneously recorded by a separate, specially modified solar-tracking video camera. The basic theory and analytical techniques used to determine beam centroid error {i.e., heliostat pointing errors), the actual incident beam power, spillage power off the receiver, and solar radiance distribution are described. The computer system is presented including the automatic data acquisition mode, the interface with the heliostat array controller (HAC), and the data acquisition system (DAS). Data display for plant operator purposes and additional data acquired and stored for more detailed engineering evaluations are discussed. Advanced applications of the DIR such as determination of total incident flux on a receiver from a field of heliostats, reflectance monitoring, and measurement of atmospheric attenuation are presented. Introduction Early in the development of solar central receivers, it was recognized that some means of aligning, monitoring, and evaluating large numbers of heliostats would be required. To meet these objectives, a digital image radiometer (DIR) was conceived in 1974 at McDonnell Douglas Astronautics Co. as part of a company-funded solar research and development program. This early DIR system consisted of a video camera, video digitizer, elevated target with several radiometers, and computers. This system was used to evaluate heliostats in desert tests conducted in 1974-1975 and 1976-1977 at the Naval Weapons Center An improved version was installed in late 1977 at the MDAC Huntington Beach Solar Energy Test Facility and used to evaluate various mirror modules and heliostats. A similar device was developed at Sandia National Laboratories Central Receiver Test Facility in 1979, and used extensively in the evaluation of various heliostats The basic DIR approach was originally selected because it offered high resolution, high acquisition rates, and real-time visual monitoring, used passive targets, required little maintenance, and was the lowest cost system when compared Contributed by the Solar Energy Division and presented at the Solar Energy Conference, Las Vegas, Nev., 1984. Manuscript received by the Solar Energy Division, November, 1984. with calorimeters or arrays of moving or stationary point detectors mounted on the tower. These advantages, coupled with successful experience with the first DIR systems at MDAC and Sandia, led to selection of the DIR as the beam characterization system (BCS) at the Solar One 10 MWe pilot plant in Daggett, Calif. Additional requirements imposed on this system involved automatic operation, sophisticated integration with other subsystems, and a variety of options for acquiring, storing, and analyzing on-line and off-line data. This system provides an automatic update of heliostat-tracking-aimpoint biases and monitors heliostat optical performance; it has been operational since September 1982 [7]. Improvements were made in 1984, such as the addition of a camera to track the sun and determine the solar radiance distribution simultaneously with each beam scan. The BCS now provides comparisons of observed beam shape with computer codes that use solar radiance distribution data and theoretical heliostat optical characteristics to evaluate performance. Beam Characterization System (BCS) Design The Solar One beam characterization system characterizes the reflected beam from a heliostat or mirror module, with respect to flux distribution and beam size, shape, centroid, and power. The BCS is used to align and evaluate heliostats as part of the pilot plant functional and integrated acceptance test program, and provides operational support for collector subsystem realignment, performance evaluation, and maintenance throughout plant operation. The overall system design and special component design features are described below. System Design. The BCS is based on the DIR measuring and recording instrument and is shown in Additional radiometers located in the field as part of the data acquisition subsystem (DAS) determine incident solar irradiance, which is used to establish heliostat reflective efficiency as measured at the target. Beam centroid data are obtained to establish heliostat aimpoints. Component Design Features Video Camera. The video camera is a Model 2850C-207 low-light television camera manufactured by COHU, Inc., Electronics Division. The camera is equipped with an RCA Model 4532 B/H silicon diode array vidicon tube and a COHU Model 2820 C-204 10:1 zoom lens with a 2X extender. Features include remote or automatic iris and zoom control, antiglare shields, sealed environmental housing, dual-tone modulated frequency (DTMF) control from the BCS computer interface, and a stable platform to minimize camera movement and wind-induced vibration. The antiglare shields eliminate stray light from clouds, receiver, sun, etc., which could cause erroneous measurements. The shields are formed to match the shape of the target and two or three are used as multiple light baffles. Circuit modifications eliminate automatic gain control types of responses and a black-level mask located at the edge of the image is used as a reference to ensure constant black level over a wide temperature range. These modifications allow the camera to operate as a radiometer, with light level controlled by iris settings and filters. The camera has a relay lens for the black-level mask and space for a variety of filters used to flatten the response of the camera over its spectral response range. Dual Tone Modulated Frequency (DTMF) Camera Control System. Camera selection and light control are accomplished by a noise-resistant tone-command system composed of a transmitter in the camera control rack and a remote receiver near each camera. The transmitter is a COHU Model DTMF 100 modified for Solar One application. Integral manual control switches are provided to select the desired camera, apply power, and control the iris or place it in automatic mode. Reed relay outputs from the MODCOMP Model 1136 module in the BCS computer provide programmable camera selection and iris control. Camera control commands are encoded to digital form and transmitted to the selected receiver over standard twisted-pair wires using audio tones to represent the digital information. The transmitter also sends camera-select commands to route the desired video input through the video switch to the digitizer. The COHU Model DTMF 200 receiver decodes the command data from the transmitter and provides power and iris control commands to the associated video camera. Video Switch. The video switch is a Pelco Model VS504R switching matrix, which routes the selected video input (north, south, east, west, or sunshape camera) to the video digitizer. Video Digitizer. The video digitizer system is a Quantex Model DS-12 digital image memory/processor. This system (1) accepts the video signal from the video camera (conforming to the EIA RS-170 standard), (2) converts the signal to a digital form, (3) stores the digital data, and (4) transmits the data to the BCS computer upon command over an IEEE 488 interface. Incoming composite video is stripped of sync and applied to a high-speed A/D converter. Data from the A/D passes through the arithmetic process where it may be combined with a memory data through hardwired arithmetic processes that include summation with data already in memory, averaging, and subtraction. The resulting data are then stored in memory. The IEEE 488 interface connects the digital memory port and the system control microprocessor to the MODCOMP Model 5488 controller in the BCS computer. This interface connects the digitizer to a direct memory access channel of the BCS computer and allows block transfer of image data and program control of the digitizer functions. A standard EIA RS-170 video output is routed to the BCS monitor CRT in the receiver console in the control room. Processed data are routed through a D/A converter to the digitizer or unprocessed data may be selected. Operation. Automatic BCS operation normally occurs when the plant is operational. Heliostats are automatically selected from a file, or heliostat candidate list, so that 60 heliostats can be tested each day. To avoid stray beams from heliostats in an adjacent quadrant, opposite quadrants and targets are tested; that is, the north and south field heliostat beams are sequentially moved onto the north and south targets while the east and west field heliostats continue to track on the receiver. Later, the east and west field heliostats are sequentially tested. Three runs are taken during the day (morning, noon, afternoon) so that the tracking aimpoint variations can be assessed and a nominal aimpoint selected. This procedure is used because heliostat aimpoints often exhibit a diurnal variation. At the end of the day, the aimpoint data, based on the measured beam intensity centroids, are used to bias the heliostat tracking data in the heliostat array controller (HAC) and thus correct the aimpoint. The HAC controls the heliostats so that each beam is moved on and off the target as required. As each selected heliostat is trained on the target, the appropriate video camera is switched to view the beam and the video signal is digitized and transmitted to the BCS computer. The BCS computer processes the digitized data, correlates the data with absolute intensity measured by target-mounted radiometers, and outputs the processed data on a CRT display terminal that has hardcopy capability. A computer program resident in the BCS determines which heliostats could block or shadow the test heliostat. The beam from the test heliostat is then moved from the receiver to a standby aimpoint, the interfering heliostats are commanded to face-up stow positions, and the test heliostat beam is then directed at the target. The 8-bit video digitizer takes an "image grab" and the computer analyzes the data. If the beam is too bright (the digitizer shows saturated values) or too dim (peak values less then 150), the camera iris is adjusted automatically to obtain the correct brightness range. Five image grabs are then taken and stored in rapid succession. A calibration curve is constructed from the digitized brightness values at the three points on the target where the radiometers are located and the corresponding radiometer measurements of irradiance (W/m 2 ). A total of 15 data points is obtained, from which a curve relating brightness to irradiance is determined. A message is then sent from the BCS to the HAC that the beam scans are complete, the HAC moves the beam off the target, and a rapid series of background image grabs is taken. The background brightness values are subtracted from the previous beam brightness values taken 5 to 30 seconds previously. The calibration curve is used to obtain the net irradiance corresponding to each pizel. Calculations are then made of beam centroid, beam power, spillage power, etc., as described in the following sections. Immediately after the last beam scan, an image grab is taken of the sun and the corresponding irradiance is measured by an adjacent Eppley pyrheliometer. Correlation of the digitized video image of the sun and the measured irradiance gives the radiance (W/m 2 steradian). This procedure is followed sequentially at a rate of roughly 15 to 30 heliostats per hour with most of this time period required for repositioning interfering heliostats. Principle of Operation. The BCS acquires a large number (256 x 256) of relative brightness values (termed DIR numbers) with a video scan. These qualitative brightness data can be transformed into quantitative irradiance data using the calibration technique that associates the brightness at several points on the target with simultaneous, quantitative radiometer measurements taken at those points. The calibration curve obtained is then applied to all of the brightness values so that the irradiance at each pixel, the net beam power, the centroid of the beam, and the isoflux contours can be determined. In order to achieve reasonable accuracies, however, a number of requirements must be met, as discussed below. Alignment. The principal requirement for accurate power measurement is that the beam must cover at least one of the three central radiometers, preferably with the higher irradiance region of the beam. Because the Solar One heliostats have a single mirror-module cant angle configuration, beam irradiance for outer row heliostats shows a central maximum and a gradual decrease with increasing radius from the beam center. Close-in heliostats show little overlap and exhibit a great deal of nonuniformity; each mirror module is distinguishable, as are the spaces between the modules. As a result, close-in heliostats may cover a radiometer with a rapidly varying irradiance distribution or slope, and heliostat movement further changes the irradiance on the radiometer. These effects decrease accuracy by increasing the data spread for the calibration curve. Power measurement accuracy is therefore greater for outer field heliostats that normally give good calibration-curve results. Because of this close-in heliostat nonuniformity, multiple heliostat scans are taken (usually five) from which 15 data points correlating irradiance and brightness are obtained. The increase in data improves the curve fit. Heliostat initial alignment has some relatively large errors (centroid error up to 1 to 3 meters) and thus some beams barely cover even one radiometer. In this case, power measurement results are not accurate, but the beam centroid data are in general accurate and a bias update can be achieved. Subsequent tests of this redirected beam give more accurate beam power and centroid results. Shading Corrections. Response over the vidicon tube face normally exhibits a relatively flat maximum near the center and drops off in the outer region. This nonunifority is corrected by an algorithm that increases the brightness (or DIR number) in the proper proportion, depending on the pixel position. The correction data are obtained by periodically pointing the camera into an integrating sphere that has uniform illumination. An image grab is taken and stored as a corrective "white file." Similarly, an image grab is taken without any light to obtain a black file. The correction is then applied as a proportional increase of the actual image file, pixel by pixel, based on the response to uniform illumination. Brightness/Irradiance Correlation. Accurate results are dependent on the correlation of a brightness value obtained at a point on the target with the corresponding irradiance measured at that point at nearly the same instant. Either of two methods is used to accomplish this. The first method uses a shutter at each radiometer, coated with the target paint. When the shutter is open, the radiometer measures the irradiance and immediately after the shutter is closed, the video digitizer takes a "frame grab." The brightness of that particular spot on the beam can then be correlated with the irradiance reading immediately prior to shutter closure. The time between the two measurements is approximately 0.5 to 1 second. This technique is workable for beams having reasonably uniform irradiance and little rapid beam movement. For beams having an irregular irradiance distribution, and beam movement, the correlations show increased scatter. The second method is to leave the shutters open and obtain data on brightness from the adjacent pixels. This approach was originally used for the NWC tests [1], The average brightness is then correlated with the radiometer reading taken at the same instant. This technique has proven to be more accurate and efforts are planned to improve this technique by reconfiguring the shutter opening and further reducing the time delay. In principle, the radiometer as seen by the camera is darker than the immediate surrounding target area, but since the radiometer and target hole size can be less than the characteristic dimensions of a pixel (~ 5 cm/pixel), the camera response to this dark region is slight. In addition, iteration techniques are used to determine the brightness that would have been observed at the radiometer, if the target hole were negligibly small and the target reflectance were thus uniform. Background. The target background irradiance is time and position dependent as a result of incident light variations on the target from the sun, clouds, ground, and especially, wideangle scattering from the heliostats. The time between a power scan and background scan is approximately 5 to 30 seconds, and slight background changes can occur. Since background area is several times the beam area, a relatively small change in background can introduce a nonnegligible error in net beam power. Several techniques are used to minimize this effect. First, if incident solar irradiance is changing rapidly, a flag is set, alerting an evaluator that conditions may be changing rapidly. Second, the background brightness on the target periphery is monitored continuously and the background values adjusted so as to nearly correspond to the values during the time the individual beam scans were taken. Third, the region outside the beam is examined by an algorithm that adjusts the difference so that it becomes minimal. In effect, the region outside the beam should have a net irradiance of zero when the total irradiance minus the background irradiance is examined

Novel modified zeolites for energy-efficient hydrocarbon separations.

We present synthesis, characterization and testing results of our applied research project, which focuses on the effects of surface and skeletal modification of zeolites for significant enhancements in current hydrocarbon (HC) separations. Zeolites are commonly used by the chemical and petroleum industries as catalysts and ion-exchangers. They have high potential for separations owing to their unique pore structures and adsorption properties and their thermal, mechanical and chemical properties. Because of zeolites separation properties, low cost, and robustness in industrial process, they are natural choice for use as industrial adsorbents. This is a multidisciplinary effort to research, design, develop, engineer, and test new and improved materials for the separation of branched vs. linear organic molecules found in commercially important HC streams via adsorption based separations. The focus of this project was the surface and framework modification of the commercially available zeolites, while tuning the adsorption properties and the selectivities of the bulk and membrane separations. In particular, we are interested with our partners at Goodyear Chemical, on how to apply the modified zeolites to feedstock isoprene purification. For the characterization and the property measurements of the new and improved materials powder X-ray diffraction (PXRD), Residual Gas Analyzer-Mass Spectroscopy (RGA-MS), Electron Microscopy (SEM/EDAX), temperature programmed desorption (TPD) and surface area techniques were utilized. In-situ carbonization of MFI zeolite membranes allowed for the maximum separation of isoprene from n-pentane, with a 4.1% enrichment of the binary stream with n-pentane. In four component streams, a modified MFI membrane had high selectivities for n-pentane and 1-3-pentadiene over isoprene but virtually no separation for the 2-methyl-2-butene/isoprene pair

Use of an orthovoltage X-ray treatment unit as a radiation research system in a small-animal cancer model

<p>Abstract</p> <p>Background</p> <p>We explore the use of a clinical orthovoltage X-ray treatment unit as a small-animal radiation therapy system in a tumoral model of cervical cancer.</p> <p>Methods</p> <p>Nude mice were subcutaneously inoculated with 5 × 10⁶HeLa cells in both lower limbs. When tumor volume approximated 200 mm³treatment was initiated. Animals received four 2 mg/kg intraperitoneal cycles (1/week) of cisplatin and/or 6.25 mg/kg of gemcitabine, concomitant with radiotherapy. Tumors were exposed to 2.5 Gy/day nominal surface doses (20 days) of 150 kV X-rays. Lead collimators with circular apertures (0.5 to 1.5 cm diameter) were manufactured and mounted on the applicator cone to restrict the X-ray beam onto tumors. X-ray penetration and conformality were evaluated by measuring dose at the surface and behind the tumor lobe by using HS GafChromic film. Relative changes in tumor volume (RTV) and a clonogenic assay were used to evaluate the therapeutic response of the tumor, and relative weight loss was used to assess toxicity of the treatments.</p> <p>Results</p> <p>No measurable dose was delivered outside of the collimator apertures. The analysis suggests that dose inhomogeneities in the tumor reach up to ± 11.5% around the mean tumor dose value, which was estimated as 2.2 Gy/day. Evaluation of the RTV showed a significant reduction of the tumor volume as consequence of the chemoradiotherapy treatment; results also show that toxicity was well tolerated by the animals.</p> <p>Conclusion</p> <p>Results and procedures described in the present work have shown the usefulness and convenience of the orthovoltage X-ray system for animal model radiotherapy protocols.</p

Myeloid Cells Contribute to Tumor Lymphangiogenesis

The formation of new blood vessels (angiogenesis) and lymphatic vessels (lymphangiogenesis) promotes tumor outgrowth and metastasis. Previously, it has been demonstrated that bone marrow-derived cells (BMDC) can contribute to tumor angiogenesis. However, the role of BMDC in lymphangiogenesis has largely remained elusive. Here, we demonstrate by bone marrow transplantation/reconstitution and genetic lineage-tracing experiments that BMDC integrate into tumor-associated lymphatic vessels in the Rip1Tag2 mouse model of insulinoma and in the TRAMP-C1 prostate cancer transplantation model, and that the integrated BMDC originate from the myelomonocytic lineage. Conversely, pharmacological depletion of tumor-associated macrophages reduces lymphangiogenesis. No cell fusion events are detected by genetic tracing experiments. Rather, the phenotypical conversion of myeloid cells into lymphatic endothelial cells and their integration into lymphatic structures is recapitulated in two in vitro tube formation assays and is dependent on fibroblast growth factor-mediated signaling. Together, the results reveal that myeloid cells can contribute to tumor-associated lymphatic vessels, thus extending the findings on the previously reported role of hematopoietic cells in lymphatic vessel formation

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Design and Geometry of Face-Gear Drives,

The authors have developed the analytical geometry of face-gear drives, proposed the method for localization of bearing contact, developed computerized simulation of meshing and bearing contact, investigated the influence of gear misalignment on the shift of bearing contact and transmission errors. Application for design is discussed. The obtained results are illustrated with numerical examples. Introduction This paper is based on the research that was performed at the University of Illinois at Chicago (UIC), Lucas Western Inc. (LW), and McDonnell Douglas Helicopter Co. (MDH). The research was initiated and supported financially by MDH. Face-gear manufacturing equipment is a product of the Fellows Corporation. Face-gears have had widespread use in low power applications but have not had much development of design and manufacturing practice for high power use. The theory of face-gear drives has not been developed sufficiently for the needs of the designers and manufacturers. The contents of this paper cover the main problems of design and manufacturing of face-gear drives with intersected axes where the drive pinion is a spur gear. The research performed is based on methods that have been developed by F. L. Litvin The paper covers the following topics: (1) localization of bearing contact; (2) meshing of shaper with the face-gear being generated; (3) limitation of length of face-gear teeth caused by pointing and undercutting; (4) computerized simulation of meshing and contact of pinion-face-gear tooth surfaces (TCATooth Contact Analysis); and (5) results of TCA. Generation of Face-Gear Drives with Localized Bearing Contact The generation of the face-gear by a shaper is shown in Transactions of the ASME Copyright © 1992 by ASME contacting surfaces and results in the undesirable contact at the edge. To avoid this, it is necessary to use a shaper with a larger number of teeth. The difference is denoted as AN = N s -Ni = 1 -3 (iVi is the number of the pinion teeth). The geometric aspects of localization of bearing contact are illustrated with drawings of The contact of the pinion and the face-gear surfaces under the load is a contact over an elliptical area; the center of such an ellipse is the theoretical contact point of E 2 and E^ The input design data for an example of a face-gear drive are given in Meshing of the Shaper and the Face-Gear The shaper tooth surface Z s and the face-gear tooth surface E 2 contact each other at every instant at a spatial line L s2 . Contact lines on E s and E 2 are shown in (/) Contact lines on the shaper surface ( Limitations of Face-Gear Tooth Surface The length of the tooth surface of a face-gear is limited, due to the possibility of undercutting by the shaper in the dedendum area and the pointing of the teeth in the addendum area The investigation of conditions of nonundercutting of the face-gear is based on the theorem that has been proposed by Litvin [5]. There is a limiting line L on the generating surface (shaper surface L s ) that generates singular points on face-gear surface E 2 . The limiting line on E s can be determined with the equation V, (s) + V (i2) = 0 (5) Here: Vr S) is the velocity of contact point in its motion over E s ; v (s2) is the sliding velocity of the shaper with respect to the face-gear. The reflection line of the conjugate meshing part and the fillet on the face-gear tooth surface is designated by L sp as shown in Computer programs for determination of limitations of the length of the face-gears have been developed at the University of Illinois at Chicago. A quick review of results obtained are represented in the following charts. Computerized Simulation of Meshing and Contact of Pinion and Face-Gear The bearing contact of pinion and face-gear tooth surfaces Ei and E 2 is localized using the technique described in section 1. Ei and E 2 are in point contact at every instant. The computerized simulation of meshing and contact of E, and E 2 (Tooth Contact Analysis) can provide information on trans-644/Vol. 114, DECEMBER 1992 Transactions of the ASME Our investigation shows that the gear misalignment (change of the shaft angle, crossing of axes instead of intersection, axial displacement of face-gear) does not cause transmission errors. This is a great advantage of face-gear drives in comparison with spiral bevel gear drive. However, gear misalignment does result in the shift of the contact path on the gear surfaces. The patterns of the bearing contact can be determined considering the motion of the instantaneous contact ellipse over the pinion-gear tooth surfaces in the process of meshing. The dimensions and orientation of the instantaneous contact ellipse can be found if the principal directions and curvatures of the contacting surfaces are determined at the current point of surface contact Theoretical and Real Contact Ratio The contact ratio m c is determined with the equation Here: &lt;/&gt;\&apos; and &lt;j&gt;\&apos; represent the angles of rotation of the pinion that correspond to the beginning and the end of meshing for one pair of teeth; N t is the number of pinion teeth. Angles 0i 2) and &lt;j&gt;\ l) can be determined from drawings of The localization of bearing contact is accompanied with the reduction of contact ratio, since the number of potential contact ellipses is reduced Conclusion The authors have developed (7) Equations of tooth surfaces of the pinion and facegear. (2) Determined limitations of tooth length to avoid tooth pointing and undercutting. Charts for fast review of such limitations have been developed. (3) A method for localization of bearing contact has been proposed. (4) A method and computer programs for simulation of meshing and bearing contact has been developed. (5) The influence of misalignment on the shift of bearing contact and transmission errors has been investigated. (6) The obtained results with numerical examples have been illustrated