An ultrasonic flowmeter for measuring dynamic liquid flow

A novel oscillating pipe system was developed to provide dynamic calibration wherein small sinusoidal signals with amplitudes of 0.5 to 10% of the steady-state flow were added to the steady-state flow by oscillating the flowmeter relative to the fixed pipes in the flow system. Excellent agreement was obtained between the dynamic velocities derived from an accelerometer mounted on the oscillating pipe system and those sensed by the flowmeter at frequencies of 7, 19, and 30 Hz. Also described were the signal processing techniques used to retrieve the small sinusoidal signals which were obscured by the fluid turbulence

A computer-controlled instrumentation system for third octave analysis

An instrumentation system is described which employs a minicomputer, a one-third octave band analyzer, and a time code/tape search unit for the automatic control and analysis of third-octave data. With this system the information necessary for data adjustment is formatted in such a way as to eliminate much operator interface, thereby substantially reducing the probability for error. A description of a program for the calculation of effective perceived noise level from aircraft noise data is included as an example of how this system can be used

Evaluation of an electro-optic remote displacement measuring system

An instrumentation system to provide a noncontact method for measurement of target positions was evaluated. The system employs two electro-optic camera units which give stereo information for use in determining three dimensional target locations. Specially developed, infrared sensitive photodetectors are used in the cameras to sense radiation from light emitting diode targets. Up to 30 of these targets can be monitored with a sampling rate of 312 Hz per target. An important part of the system is a minicomputer which is used to collect the camera data, sort it, make corrections for distortions in the electro-optic system, and perform the necesssary coordinate transformations. If target motions are restricted to locations in a plane which is perpendicular to a camera's optical axis, the system can be used with just one camera. Calibrations performed in this mode characterize accuracies in single camera operation. This information is also useful in determination of single camera contributions to total system errors. For this reason the system was tested in both the single camera and two camera (stereo) modes of operation

An investigation of thin film oxygen partial pressure sensors

Product development and testing of thin film oxygen partial pressure sensor

IPLIB (Image processing library) user's manual

IPLIB is a collection of HP FORTRAN 77 subroutines and functions that facilitate the use of a COMTAL image processing system driven by an HP-1000 computer. It is intended for programmers who want to use the HP 1000 to drive the COMTAL Vision One/20 system. It is assumed that the programmer knows HP 1000 FORTRAN 77 or at least one FORTRAN dialect. It is also assumed that the programmer has some familiarity with the COMTAL Vision One/20 system

Carbapenem Precursors From Allyl and (Allenylmethyl)silanes

Most successful syntheses of beta-lactam antibiotics involve the early generation of a monocyclic 6-lactam ring. The addition of CSI to functionalised alkenes has proven to be of great synthetic utility in this step. Generally the addition is performed on enol acetate type alkenes, the product 4-acetoxyazetidinones finding widespread use since the 4-acetoxy substituent can be replaced by a variety of nucleophiles in an elimination/addition sequence. Unfortunately none of the additions of CSI to functionalised alkenes is generally applicable to the formation of 4-carbon substituted azetidinones, which could then serve as carbapenem precursors. Earlier reports by Dunogues(1) and Fleming(2) intrigued us since the addition of CSI to allylsilanes produced N-chlorosulphonyl-O-silyl imidates via the corresponding N-chlorosulphonyl beta-lactams arising from formal [2+2] cycloaddition between the allylsilane and CSI. These intermediate beta-lactams possessed a 4-carbon substituent as found in the carbapenem series and we have been able to repeat the work of Dunogues and intercept the intermediate beta-lactams with Na2SO3 to furnish the corresponding N-protio beta-lactams(3) in yields generally superior to those of other CSI/alkene addition/reduction sequences. (4) The regiochemistry of cycloaddition is controlled by the beta-effect of silicon, i. e. , silicon's ability to stabilise the development of partial positive charge beta to itself. This is well demonstrated by the regiochemistry of addition of CSI to l-trimethylsilyl-4-methylpenta-2,3-diene, which will be described, when contrasted with the addition of CSI to 2-methylpenta-2,3-diene, which has previously been described by Moriconi. (5) Generally, yields in the addition of CSI to (allenylmethyl)silanes were low, but the 3-alkylidene-4-(silylmethyl)azetidinones produced are advanced carbapenem precursors difficult to access by other methodologies. Initial studies by Dunogues, Fleming and ourselves made use of trimethyl substituted silyl moieties which served to demonstrate the scope and utility of the method, but rendered the product azetidinones of little utility. Extending the cycloaddition to oxidatively cleavable silyl residues, namely phenyldimethyl substituted silicon moieties, furnished high yields in the cycloaddition, although a slightly lower allylsilane reactivity was observed as the trimethylsilyl substituent was replaced by a phenyldimethylsilyl moiety. Unfortunately the fluoroborane(6) and KBr/AcOOH(7) mediated procedures developed by Fleming to accomplish oxidative cleavage of the phenyldimethylsilyl species did not furnish any of the target 4-(hydroxymethyl)-azetidinone but the mercuridesilylation/oxidative rearrangement protocol, also developed by Fleming(7), accomplished the required transformation, albeit in low yield. Further synthetic manipulations were then carried out on this oxidatively cleaved 3-unsubstituted-azetidinone, namely Peterson olefination, which was found to be impossible with the corresponding 4-(phenyldimethylsilylmethyl)azetidinone, and conversion into a thienamycin precursor possessing the correct relative configuration at all three chiral centres

A study of charge storage in silicon oxide resulting from non-penetrating electron irradiation

Charge storage in silicon dioxide resulting from electron irradiatio

Charge storage effects in Mylar resulting from electron irradiation, June 1965 - June 1966

Charge storage effects in Mylar from electron irradiatio

Study of the use of Metal-Oxide-Silicon (MOS) devices for particulate detection and monitoring in the earth's atmosphere

A metal-oxide-silicon (MOS) capacitor-type particulate sensor was evaluated for use in atmospheric measurements. An accelerator system was designed and tested for the purpose of providing the necessary energy to trigger the MOS-type sensor. The accelerator system and the MOS sensor were characterized as a function of particle size and velocity. Diamond particles were used as particulate sources in laboratory tests. Preliminary tests were performed in which the detector was mounted on an aircraft and flown in the vicinity of coal-fired electric generating plants

Epistemologiese oortuigings en die onderrigen leerhandeling

Epistemological convictions with regard to teaching and learning It is often assumed by teaching-learning specialists that teaching and learning are proportionally related technical activities, and can be accurately measured in examinations or experiments. The fact that teaching and learning are respectively, as well as in combination with each other, embedded in a multitude of pre-scientific and scientific presuppositions is frequently overlooked. This discussion is aimed at revealing that views and standpoints regarding teaching and learning can hardly be substantial or plausible without cognisance and evaluation of the epistemological convictions in which they are grounded. Such convictions also determine the nature of their application in actual class-room practice