6,183 research outputs found

    IS AGRICULTURAL SECTOR GROWTH A PRECONDITION FOR ECONOMIC GROWTH? THE CASE OF SOUTH AFRICA

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    In this paper a simple growth model is adapted to explain the effect of the agricultural sectors' growth on the non-agricultural sector. The empirical results suggest that for a 1% growth in the agricultural sector, the non-agricultural sector responds by more than 1%. The results also confirm that productivity difference exists, the non-agricultural sector being more efficient in terms of input use. The empirical results support the argument of President T. Mbeki, that South Africa should follow an "agricultural-led" growth strategy for successful development.International Development,

    Testing collapse models with levitated nanoparticles: the detection challenge

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    We consider a nanoparticle levitated in a Paul trap in ultrahigh cryogenic vacuum, and look for the conditions which allow for a stringent noninterferometric test of spontaneous collapse models. In particular we compare different possible techniques to detect the particle motion. Key conditions which need to be achieved are extremely low residual pressure and the ability to detect the particle at ultralow power. We compare three different detection approaches based respectively on a optical cavity, optical tweezer and a electrical readout, and for each one we assess advantages, drawbacks and technical challenges

    Multi-Objective Discrete Particle Swarm Optimisation Algorithm for Integrated Assembly Sequence Planning and Assembly Line Balancing

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    In assembly optimisation, assembly sequence planning and assembly line balancing have been extensively studied because both activities are directly linked with assembly efficiency that influences the final assembly costs. Both activities are categorised as NP-hard and usually performed separately. Assembly sequence planning and assembly line balancing optimisation presents a good opportunity to be integrated, considering the benefits such as larger search space that leads to better solution quality, reduces error rate in planning and speeds up time-to-market for a product. In order to optimise an integrated assembly sequence planning and assembly line balancing, this work proposes a multi-objective discrete particle swarm optimisation algorithm that used discrete procedures to update its position and velocity in finding Pareto optimal solution. A computational experiment with 51 test problems at different difficulty levels was used to test the multi-objective discrete particle swarm optimisation performance compared with the existing algorithms. A statistical test of the algorithm performance indicates that the proposed multi-objective discrete particle swarm optimisation algorithm presents significant improvement in terms of the quality of the solution set towards the Pareto optimal set

    Modelling the Kinetics, Thermodynamic and Physical Properties of Coconut (Cocos nucifera L.) during Convective Drying

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    The drying kinetics, thermodynamic properties, and energy consumption of five potential coconut cultivars identified by Ghana's CSIR-Oil Palm Research Institute were studied. Drying was carried out in a convectional dryer using four temperatures (70, 80, 90 and 100oC) and 2.0 m/s air velocity. The asymptotic model was adjudged the best fit model in predicting moisture content based on the highest coefficient of determination (0.9589-0.9998) and lowest residual sum of squares (8.427-252.61), chi-square (0.52671-16.8409) and root mean square error (2.8744-3.4421). Temperature caused between 66.8-96.5% variations in moisture diffusivity. Thermodynamic study revealed endothermic and non-spontaneous reactions in the drying system resulting from enthalpy change and Gibbs free energy change. Meanwhile, a direct relation was established among higher spontaneity and higher temperature. Despite the high drying temperatures used for the experiment, internal cellular composition was not affected as a result of excellent rehydration capacity. In effect, the Vanuatu TThe drying kinetics, thermodynamic properties, and energy consumption of five potential coconut cultivars identified by Ghana's CSIR-Oil Palm Research Institute were studied. Drying was carried out in a convectional dryer using four temperatures (70, 80, 90 and 100oC) and 2.0 m/s air velocity. The asymptotic model was adjudged the best fit model in predicting moisture content based on the highest coefficient of determination (0.9589-0.9998) and lowest residual sum of squares (8.427-252.61), chi-square (0.52671-16.8409) and root mean square error (2.8744-3.4421). Temperature caused between 66.8-96.5% variations in moisture diffusivity. Thermodynamic study revealed endothermic and non-spontaneous reaction in the drying system resulting from enthalpy change and Gibbs free energy change. Meanwhile, a direct relation was established among higher spontaneity and higher temperature. Despite the high drying temperatures used for the experiment, internal cellular composition was not affected as a result of excellent rehydration capacity. In effect, the Vanuatu Tall was adjudged as the best coconut variety based on its lower energy consumption and activation energy, shorter drying time and higher moisture diffusivity. All was adjudged as the best coconut variety based on its lower energy consumption and activation energy, shorter drying time and higher moisture diffusivity

    Multi-Objective Optimisation of CNC Milling Process for Al 6061 using Modified NSGA-II

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    Computer numerical controlled (CNC) growth has revolutionised the manufacturing sectors by changing the way people work. In milling process, it has contributed to the higher productivity and better quality of the products. Although a lot of researches have been done on how to improve the process, the process improvement does not stop there because of evolving materials, methods and technologies. This paper presents a multi-objective optimisation of CNC milling process in order to achieve desired surface roughness and minimise machining time for Al 6061. A full factorial experiment has been conducted to model surface roughness by controlling three variables; spindle speed, feed rate and depth of cut. Multi-objective optimisation has been performed using modified Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) with two levels crossover. The optimisation result concluded that the modified NSGA-II was able to converge to Pareto-optimal, but having difficulties to spread solutions in wider range

    On the unitarity of higher-dervative and nonlocal theories

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    We consider two simple models of higher-derivative and nonlocal quantu systems.It is shown that, contrary to some claims found in literature, they can be made unitary.Comment: 8 pages, no figure

    Hydrophobicity properties of graphite and reduced graphene oxide of the polysulfone (PSf) mixed matrix membrane

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    Hydrophobicity properties of graphite and reduced graphene oxide (rGO) (from exfoliated graphite/rGO) towards PSf polymer membrane characteristic and properties at different additives weight concentrations (1, 2, 3, 4 and 5 wt. %) were investigated. Both PSF/graphite and PSf/rGO membranes were characterized in term of hydrophobicity, surface bonding, surface roughness and porosity. FTIR peaks revealed that membrane with graphite and reduced graphene oxide nearly diminished their O-H bonding which was opposite to the graphene oxide peak that shows a strong O-H bonding as increased exfoliated times. These results were in line with the contact angle results that showed strong hydrophobicity of graphite and reduced graphene oxide membranes as increased these additives concentration. The effect of strong hydrophobicity in these membranes also has resulted in smoother surface roughness compared to pristine PSf membrane. Further investigation of the performance of water flux also proved that both above membranes have strong hydrophobic effect, with the lowest pure water flux rate (L/m2h) was given by PSf/rGO 3% membrane at 19.2437 L/m2h

    Dietary effect of red paprika used to enhance the coloration of red tilapia (oreochromis niloticus)

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    Red tilapia (Oreochromis niloticus) is one of the famous fish cultures in the aquaculture industry, especially in Malaysia. The appearance of redness makes the fish more attractive for customers to buy. Therefore, to achieve quality products it is necessary to research how to improve the color quality of tilapia as desired by customers. The purpose of this study was to identify the dietary effect of red paprika used to enhance the coloration of red tilapia. This study is an experimental quantitative study. Red tilapia was obtained from Freshwater Hatchery, University Malaysia Terengganu. A descriptive analysis was used to analyze the data in this study. This study shows that red paprika has an effect on the length and weight of red tilapia, where the highest length and weight gained (1.79 cm and 12.37 g) given red paprika 2% and the lowest length and weight gained (0.63 cm and 2.5 g) which given 4% red paprika. Only 2% of red paprika treatment showed different growth performance. The crude protein, lipid, and moisture composition of tilapia were also higher at 2% red paprika treatment. Meanwhile, the highest composition of ash is feed with 4% red paprika content. The result of this research showed that the caudal and dorsal either muscle or fin showed the highest color at the fish which fed with 8% red paprika. It could also improve the coloration of the red tilapia. Future studies suggest the use of Dunaliella salina microalgae which is one of the richest sources of carotenoids

    Nutritional Evaluation and Physicochemical Properties of Fermented Shirezh Dairy Product

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    Many of the Kurdish traditional dairy products have not been studied thoroughly so far though are still produced at small scale. Dow (sour butter milk) and Shirezh are among these products. Shirezh known to Iraqi Kurds as sour concentrated Dow. The characteristics of Shirezh and Dow were: pH (5.5, 4.05), acidity (2.13%, 1.10%), total solids (18.70%, 5.32%), ash (0.62%, 0.45%), fat (2.57%, 0.8%) and total protein (13.59%, 3.28%) respectively, furthermore the amino acids of Shirezh’s protein found in balanced and acceptable quality. The aim of this research is to introduce Shirezh and Dow to scientific literature and to determine their characterization and nutritional values. Keywords: Shirezh, Dow, Dairy, Fermented, Nutrition, Physicochemical, Amino acids
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