(S)-Benzyl 3-phenyl­carbamoyl-1,2,3,4-tetra­hydro­isoquinoline-2-carboxyl­ate

There are two independent mol­ecules in the asymmetric unit of the title compound, C24H22N2O3. The heterocyclic ring assumes a twisted boat conformation and N—H⋯O inter­actions help to construct the three-dimensional network within the crystal packing

Community Engagement newsletter, Faculty of Veterinary Science, Winter 2014

Putting our best paw forward / Kirsten Collins and David Chelopo -- Veterinary outreach sees great success in the mountain kingdom! / Nicolle Gray -- The Husky Rescue Centre Project / Sone Reyneke.Originally published as HTML file, converted to PDF with Adobe Acrobat 9 Pro Version 9.0.0.News articles with colour photos about the various community engagement projects of the Faculty of Veterinary Science, University of Pretoria.ab201

Stereoselective synthesis of 1,3-disubstituted dihydroisoquinolines vial-phenylalanine-derived dihydroisoquinoline N-oxides.

The preparation of chiral pool-derived nitrone 3 and its use in the protecting-group free, stereoselective synthesis of a range of 1,3-disubstituted tetrahydroisoquinolines is described. Grignard reagent additions to nitrone 3 yielded trans-1,3-disubstituted N-hydroxytetrahydroisoquinolines 6 with good levels of selectivity, while 1,3-dipolar cycloadditions to this nitrone provided access to 3-(2-hydroxyalkyl)isoquinolines 12 as single diastereomers

An investigation into the most efficient brake disc material for application on overland and decline belt conveyor systems

Abstract: A disk brake system has three essential functions, namely, reducing the moving conveyor speed, preserving its steady downhill speed, and stopping the conveyor fully during normal or emergency operation. There has been a persistent demand in recent years for lightweight disks with highly efficient energy-absorbing structures and materials in the overall conveyor system. This aspiration has led to experimental work in an attempt to use various materials for engineering designs. In this work, a rotating annular disc subjected to in-plane frictional loads is analytically modelled on the brake system. In order to obtain modal properties of braking for inputs into the finite element model, the experimental modal test of the disc brake device under free boundary conditions is performed. The goal of my research is to recognize various properties that may in the future enable us to optimize working parameters and increase braking system efficiency. The findings will enable us to achieve the optimal functionality of this structure to improve the operational disc life or performance. ANSYS 19.2 academic finite element software has been used to analyse stress accumulation, structural deformation, and brake disk interaction pressure during a single braking stop event. This work thus provides an important orientation for the design and progress of the brake disk and the brake liner pad. Structural and Thermal analysis with complementary experiments is therefore preferred method used to access and to choose the most efficient brake disc material for improved performance. The Finite Element Approach (FEM) was used to perform a study of four brake disk compounds...M.Tech. (Mechanical Engineering

Physiological responses of African elephant (Loxodonta africana) immobilised with a thiafentanil-azaperone combination

Objective To determine the cardiopulmonary and blood gas status of elephants during chemical capture (immobilisation) with a thiafentanil-azaperone drug combination kept in lateral recumbency. Study design Prospective descriptive study. Animal population Ten free-ranging adult African elephant bulls (estimated weight range 3000 to 6000 kg). Methods Elephants were immobilised using a thiafentanil (15-18 mg) and azaperone (75-90 mg) by darting from a helicopter. Once recumbent, the tidal volume, minute volume, end-tidal carbon dioxide, arterial blood pressure and pulse rate were recorded immediately after instrumentation and at five-minute intervals until T20. Arterial and venous blood gases were analysed at the time of initial instrumentation and at 20 minutes. On completion of the data collection, the thiafentanil was antagonised using naltrexone (10 mg mg-1 thiafentanil). A stopwatch was used to record time to recumbency (dart placement to recumbency) and time to recovery (administering antagonist to standing). Data was checked for normality and was found to be parametric. Data were compared using a one-way analysis of variance and reported as mean (± SD). Results All elephants were successfully immobilised and all physiological variables remained constant with minimal non-significant variation over time. Average time to recumbency was 12.5 minutes. The estimated expiratory tidal volume was 21 (± 6) L breath-1 or 4.8 ± 0.8 mL kg-1, and the measured minute volume was 103 (± 31) L minute-1. The heart and respiratory rates were 49 (±6) beats and 5 (± 1) breaths minute-1, respectively. The mean arterial blood pressure was 153 (± 31) mmHg. The elephants were acidaemic (pH 7.18 ±0.06; bicarbonate ion 20 ±4 mmol L-1; lactate 11 ± 4 mmol L-1), mildly hypoxemic (PaO2 68 ± 15 mmHg) and mildly hypercapnic (PaCO2 52 ± 7 mmHg). Average time to recovery was 2.2 minutes. Conclusion and clinical relevance African elephant bulls can be successfully immobilised using thiafentanil-azaperone. Recumbency was rapid, the cardiopulmonary variables were stable and within acceptable ranges, and recovery was rapid and complete. Mild hypoxaemia and hypercapnia were evident, but does not necessarily require oxygen supplementation.Dissertation (MSc)--University of Pretoria, 2020.Companion Animal Clinical StudiesMScUnrestricte

Structural analysis on mild-steel and aluminium brake disk for application on belt conveyor

Abstract: A disk brake system has three essential functions, namely, reducing the moving conveyor speed, preserving its steady downhill speed and stopping the conveyor fully during normal or emergency operation. There has been a persistent demand in recent years for light weight disks with highly efficient energy-absorbing structures and materials in the overall conveyor system. This aspiration has led to experimental work in attempt to use various materials for engineering designs. In this article, a rotating annular disc subjected to in-plane frictional loads is analytically modelled on the brake system. In order to obtain modal properties of breaking for inputs into the finite element model, the experimental modal test of disc brake device free under free boundary conditions is performed. The goal of this research is to recognize various properties that may in future enable us to optimize working parameters and increase braking system efficiency. The findings will enable us to achieve the optimal functionality of this structure to improve the operational disc life or performance. The aim of this document is to examine stress concentration, structural deformation and brake disk contact pressure during a single braking stop event using ANSYS 19.2 academic finite element software. This research therefore provides an important guide to the design and engineering of the brake disk and the brake pad. Structural and stress analysis are therefore preferred to pick the lightweight material for improved performance. Consequently, the lightweight material may be recommended to reduce the conveyor working load and preserve operational energy consumption, provided that light weight will satisfy working duty requirements. Comparing the results achieved with those of the technical literature, the simulation is satisfactory