The influence of extraction techniques on the chemical composition of essential oils from Pelargonium cv.rose in the Eastern Cape
- Authors: Ngcangatha-Maqhude, Bulelwa
- Date: 2017
- Subjects: Essences and essential oils Pelargoniums Rose geranium oil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8111 , vital:31524
- Description: Rose geranium is a world known essential oil plant priced for its high grade essential oil mostly utilized in the perfumery industry. However, South Africa has just joined the geranium oil production industry and still battling with the variations in oil yield and composition. Volatile components from Rose geranium were respectively extracted by three methods including hydro-distillation, steam distillation and solvent free microwave. The composition was characterized by GC-FID and GC-MS .No significant differences were found in the oil constituents, colour of the oil was the same in hydro-distillation and steam distillation (light green) but in solvent free microwave extraction the oil was clear because in the receiving flask there was hexane and the quantity of the oil was not the same. The difference was the time taken to extract the oil: Hydro-distillation took 3 hours, steam distillation took 1 hour, 30 minutes and solvent free microwave took only 30 minutes. The main constituents of the essential oil of rose geranium (steam distillation) are Dohne: Citronellol (20.61percent), geraniol (14.79percent), linalool (1.98percent), citronellyl formate (14.25percent), geranyl formate (10.25percent) and guaiadiene 6, 9 (7.22percent). Kieskammahoek: Citronellol (20.36percent), geraniol (9.81percent), linalool (1.54percent), citronellyl formate (16.09percent), geranyl formate F (8.96percent) and guaiadiene 6, 9 (8. 22percent).University of FortHare: Citronellol (21.55percent), geraniol (9.41percent), linalool (1.40percent), citronellyl formate (16.37percent), geranyl formate (8.10percent) and guaiadiene 6, 9 7.92percent). For hydro-distillation, Dohne: Citronellol (24.68percent), geraniol (11.68percent), linalool (11.74percent), citronellyl formate (14.97percent), geranyl formate (5.95percent) and guaiadiene 6, 9 (4.63percent). Kieskammahoek: Citronellol (25.25percent), geraniol (13.44percent), linalool (3.35percent), citronellyl formate (15.62percent), geranyl formate (5.40percent) and guaiadiene 6, 9(4.96percent).University of FortHare: Citronellol (24.73percent), geraniol (8.35percent), linalool (9.76percent), citronellyl formate (16.54percent), geranyl formate (4.42percent) and guaiadiene 6, 9(9.76percent). The solvent free microwave extraction , Dohne: Citronellol (20.87), geraniol (17.85percent), linalool (1.21percent), citronellyl formate (13.44percent), geranyl formate (10.26percent) and guaiadiene 6, 9 (4.59percent).Kieskammahoek: Citronellol (20.13percent), geraniol (5.40percent), linalool (0.28percent), citronellyl formate (14.22percent), geranyl formate (6.04percent) and guaiadiene 6, 9(8.63percent).University of FortHare: Citronellol (21.15percent), geraniol (22.36percent), linalool (1.37percent), citronellyl formate (12.13percent), geranyl formate (8.91percent) and guaiadiene 6, 9 (5.82percent).The percentage of oil composition in hydro-distillation and Solvent Free Microwave Extraction was higher than steam distillation.
- Full Text:
- Date Issued: 2017
Explanation in rule-based expert systems
- Authors: Carden, Kenneth John
- Date: 1988
- Subjects: Expert systems (Computer science) Ecology -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4569 , http://hdl.handle.net/10962/d1002034
- Description: The ability of an expert system to explain its reasoning is fundamental to the system's credibility. Explanations become even more vital in systems which use methods of uncertainty propagation. The research documented here describes the development of an explanation sub-system which interfaces with the P.R.O. Expert System Toolkit. This toolkit has been used in the development of three small ecological expert systems. This project has involved adapting the results of research in the field of explanation-generation, to the requirements of the ecologist users. The subsystem contains two major components. The first lists the rules that fired during a consultation. The second component comprises routines responsible for quantifying the effects on the system conclusions of the answers given to questions. These latter routines can be used to perform sensitivity analyses on the answers given. The incorporation of such routines in small expert systems is quite unique
- Full Text:
- Date Issued: 1988
The importance of habitat use in the foraging behaviour of village chacma baboons (Papio ursinus, Cercopithecidae: Primates) in Hogsback, Eastern Cape
- Authors: Pamla, Lwandiso
- Date: 2016
- Subjects: Chacma baboon -- Behavior -- South Africa -- Eastern Cape Cercopithecidae Primates -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8055 , vital:31494
- Description: Baboons are among the most widespread primates in Africa because they are able to adapt their foraging behaviour and omnivorous diet under challenging and changing conditions. They are attracted by food, shelter and water on human-owned properties, which brings them into conflict with the residents in Hogsback, Eastern Cape, South Africa, and results in them being shot, trapped or poisoned. To quantify the proportion of food baboons obtain from raiding human properties and to assess the quality of this food, I recorded activity budgets for foraging and movement in two free-ranging troops (Evie’s and Nola’s troops) using direct field observation. I determined home range sizes using GIS methods. I hypothesised that a troop that frequents more human-modified areas should have smaller home ranges, higher densities and forage less than a troop that spends more time in natural habitats, irrespective of troop size, because of more readily accessible food sources. The three methods I used (100 percent minimum convex method, 95 percent fixed kernel method and quadrat method) revealed that Evie’s troop used more human-modified habitat, but had a larger home range than Nola’s troop. The troop sizes have been stable for the past four years: at last count, Evie’s troop had 47 individuals and Nola’s, 38 individuals. During my field study I also recorded diverse vocalisations made by the animals, as an aid to detecting and identifying the troops and understanding individual interactions. Responses to the presence of baboons of many of the local residents – whether affluent and living on semi-urban estates, or impoverished and hunting for food – do not augur well for the future of Hogsback’s baboons. Affluent residents with horticultural gardens occasionally shoot baboons that venture on to their properties, while rural occupants hunt baboons in their natural environment. Both of these responses cause troop disruption and decreased troop size, possibly leading to local troop extinctions.
- Full Text:
- Date Issued: 2016
How phase feeding manipulation affects growth, performance, feed cost, carcass characteristics and the quality of meat from broilers
- Authors: Sokanyile, Sanda
- Date: 2017
- Subjects: Animal nutrition Feeds Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5565 , vital:29334
- Description: The main objective of the study was to determine how phase feeding manipulation affects growth performance, feed cost, carcass characteristics and quality of meat from broiler chickens. A total of 180 day old un-sexed broiler chicks (Cobb 500) were separated into 3 dietary treatments of 60 birds per treatment and each treatment was replicated 3 times with 20 birds per replicate. The dietary treatments were as follows: T1 (starter 1-7 days; grower 8-21 days; finisher 22-35 days), T2 (starter 1-14 days; grower 15-21 days, finisher 22-35 days) and T3 (starter 1-14 days; grower 15-28 days; finisher 29-35 days). Feed intake and body weight gains were recorded weekly in kilograms. Average daily gain and feed conversion ratio were computed weekly. At day 35, the chickens were slaughtered and 12 representative breast muscles from each treatment were used for the determination of muscle pH (pH1, pH24 and pH48) and colour coordinates (Lightness – L*, redness – a* and yellowness – b*) in triplicate at 1 hour, 24 hours and 48 hours post-mortem.Feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG) and average body weight at slaughter (ABW) were not significant (P>0.05) amongst the treatments. The most cost efficient feed (which accumulated the cheapest cost feed per kg were) T1 (R11.32) and T3 (R11.32) although there was a slight difference in the gross profit of these treatments T1 (R45.71) and T3 (R44.48). Carcass characteristics were the same (P > 0.05) across the treatments except for the wing, thigh, drumstick and the breast (P < 0.05). T2 had the highest wing weight (166.63±8.60), T1 (113.03±8.60) and the lowest in T3 (74.46±8.60). The thigh weight were greater (P<0.05) in T2 (185.69±4.34); T1 (185.54±4.34) compared to T3 (166.97±4.34) which was lower. Treatments 1 (204.17±6.57), T2 (197±6.57) had heavier (P<0.05) breast weights than T3 (186.06±6.57). Dietary treatments had no significant effect (P > 0.05) on pH of the breast meat. No differences were observed in colour during the 1 hour period after slaughter. At 24 hours after slaughter, the L* values were different (P < 0.05) in T1 and T2 (44.3 ± 0.37; 43.7 ± 0.37), respectively, T1 and T3 were the same. The a*-values were different (P < 0.05) at 48 hours after slaughter for T1 and T3 (4.5 ± 0.27; 3.4 ± 0.27), T2 was the same as T1. It was therefore, concluded that since manipulation of starter phase did not have adverse effects on growth performance, gross profit, slight statistical difference in meat quality attributes and carcass characteristics. Therefore, the manipulation of starter diet has the potential to be used in broiler production.
- Full Text:
- Date Issued: 2017