A ground test measurement system for the shuttle entry air data system

The Ground Test Measurement System (GTMS) for determining vacuum decay leak rate within the orifice tubing assembly of SEADS is described. The system can also monitor the absolute pressure in the tubing assembly under certain conditions. The GTMS determines leak rate by measuring vacuum-pressure decay which can be converted into leakage flow rate. Results of performance testing and operation of the GTMS are given

Quo Vadis, opvoeder?

Enige opvoedkunde word deur sy grondbeginsels beheers, ook die Calvinistiese. Hierdie beheersing strek hom veel verder uit as slegs die grense wat deur die teorie gestel word; dit reik heen na die praktyk en die organisasie. Dit omvat die opvoeder en die opvoedeling, die opvoedingsinrigting en die beheer daarvan, die stof en die metode, die liggaam en die siel, die tydelike en die ewige bestemming. As Calviniste laat ons ons ,,in U lig” lei op al hierdie terreine, of wil ons graag daardeur gelei word

Die kultuurkrisis en die opvoeding van die jeug

Ons gaan ons besig hou met die krisis in die opvoeding en onderwys van die 20ste eeu, en veral van die tweede kwart daarvan. Ons wil direk aan die begin baie duidelik stel dat ons op hierdie terrein voortdurend krisisse belewe

A study of strength and vasoactivity in a tissue engineered vascular media

To be successful a tissue engineered small diameter blood vessel must be non-immunogenic, non-thrombogenic, have mechanical properties similar to native vessel and be vasoactive. The vascular media is responsible for the mechanical properties and the vasoactivity of the vessel. The collagen hydrogel approach has been long used and has many advantages, but has not yet achieved the mechanical integrity needed for implantation. No collagen-based tissue engineered vascular media has been shown to be vasoactive using culture techniques required to achieve the cell numbers needed to make a vascular graft. To study collagen synthesis, two model systems were used. Cells were seeded on top of an adsorbed collagen I or fibrin layer. Alternatively the cells were encapsulated in a collagen or fibrin hydrogel. Collagen I, decorin and biglycan synthesis was affected by both matrix type and presentation. After two weeks in culture the smooth muscle cells produce more type I collagen in the collagen based hydrogels then in the fibrin hydrogels and was used for further studies. The collagen based tissue engineered vascular media produced a consistent vasoactive response between two and eight weeks of culture. The smooth muscle cells have functional endothelin, kinin, adrenergic, serotonergic and purinergic receptors. The application of cyclic strain improves both the tissue strength and the contractile response. Use of transforming growth factor-β improved tissue strength, but reduced the contractile response. Transforming growth factor- β actually promoted a more contractile cell phenotype, but a stronger contractile force was required to overcome the thick compact collagen hydrogel and elicit a measurable contraction. This work adds to what is known about collagen-based tissue engineered vascular medias by identifying means of improving not only strength but vasoactivity. The trade-offs found between these two important characteristics are relevant to all tissue engineered medias.Ph.D.Committee Chair: Nerem, Robert M.; Committee Member: Gleason, Rudolf L.; Committee Member: Taylor, W. Robert; Committee Member: Vito, Raymond P.; Committee Member: Wang, Yadon

'n Pleidooi vir moderne leerplanne in die voorgraadse chemie kursus

Dis nie nét die letterkundiges wat kan spog met hulle „geslagte” nie! Ons kan die chemici van die vyftiger-jareklassifiseer as „die vyftigers” — nie soseer omdat hulle gesorg het vir opsienhaas geen poging is aangewend om die gegewens teoreties te korrelleer en te begryp nie. Chemie was net ’n opeenhopingvan empiriese gegewens (reaksies!)

H.J J. Bingle se plek in die S.A. opvoedkundige panorama

Hierdie plasing is net so maklik as wat dit moeilik is. Om ’n een-spoormens te waardeer is nie besonder moeilik nie; om so ’n veelsydig-begaafde te plaas, kan maklik uitloop op versplintering, op miskenning van die eenheidsbeginsel wat soos ’n goue draad deur elke afdeling loop, op miskenning van die mens (hele mens) wat agter dié fasette skuil. Op die gevaar af dat ons juis in die opsig die bal mag misslaan, wil ons tog hier van fasette gebruik maak. Dis prakties onmoontlik om die terreine waterdig af te sluit, en ons gaan dit ook nie probeer nie

VIGS en die Suid-Afrikaanse ekonomiese en bestuurswêreld - Enkele perspektiewe

There is no doubt anymore that AIDS as a disease has the potential to become a very serious issue in the South African social, political, demographic and economic environment. AIDS will have macro-economic as well as micro-business implications. At macro-level (without the influence of AIDS) decision-makers already anticipate and plan for a • shortage in housing for blacks; • shortage in employment opportunities; • high level of unemployment; • uncontrollable urbanisation; and a • lack of educational infrastructure. Burning issues for decision-makers and managers will be • who will be the worker tomorrow? • who will be the manager? • will there be sufficient manpower resources? • what would a training strate& took like ? • in what ways will production and productivity be managed? • in what ways will sound labour relations be created and maintained? Although a great many decision-makers and managers still have a sceptical view and perception regarding AIDS, it is certain that it will affect the entire spectrum of life. Managers should proactively plan for the implications of AIDS on business, and if projections do not realise as darkly, it could be seen and accepted as a "bonus

Die skool en die onderwyser as faktore in die geestesgesondheid van die kind*

Ons hou geestesgesondheidsweke, stig beroepsentrums, samel geld in om mense wat geestelik siek is te genees, klae oor die tekort aan psigiaters, kliniese sielkundiges, bedryfsielkundiges, voorligters, skoolpsigoloë,ens. ’n Karige kwarteeu gelede het ons aan al hierdie dinge slegs akademiese aandag gewy. In hierdie kursus wordverskeie tipes kinders bespreek en geleer hoe om hulle probleme te benader