Experimental and numerical investigations of free convection heat transfer in solar oven

The use of solar energy for baking, heating or drying represents a sustainable way of solar energy applications with negligible negative effects. Solar oven is an alternative to conventional oven that rely heavily on coal and wood or Electric oven that uses the power from the National grid of which the end users have little or no control. Since the Solar oven uses no fuel and it cost nothing to run, it use are widely promoted especially in situations where minimum fuel consumption or fire risks are considered highly important. As useful as the Solar Oven proved, it major setback in the area of applications has been its future sustainability. For the use of Solar Oven/Cookers to be sustained in the future, the design and development of solar oven must rely on sound analytical tools. Therefore, this work focused on the design and development of the solar oven. To test the performance of the Small Solar Oven a 5000cm3 beaker of water was put into the Oven and the temperature of the water was found to reach 810C after about 3hrs under an average ambient temperature of 300C. On no load test, the oven reached a maximum temperature of 112oC in 6hrs. In order to carry out the parametric studies and improve the performance of the Solar Oven, Mathematical models were developed and solved by using Characteristics-Based Split (CBS) Finite Element Method. The Model results were compared with the Experimental results and a good agreement ware found between the two results

Classical Strongly Coupled QGP: VII. Energy Loss

We use linear response analysis and the fluctuation-dissipation theorem to derive the energy loss of a heavy quark in the SU(2) classical Coulomb plasma in terms of the $l=1$ monopole and non-static structure factor. The result is valid for all Coulomb couplings $\Gamma=V/K$, the ratio of the mean potential to kinetic energy. We use the Liouville equation in the collisionless limit to assess the SU(2) non-static structure factor. We find the energy loss to be strongly dependent on $\Gamma$. In the liquid phase with $\Gamma\approx 4$, the energy loss is mostly metallic and soundless with neither a Cerenkov nor a Mach cone. Our analytical results compare favorably with the SU(2) molecular dynamics simulations at large momentum and for heavy quark masses.Comment: 18 pages, 15 figures. v2: added references, changed title, replaced figures for Fig. 7, corrected typo

Bioactivity, persistence and mobility of picloram in Selangor and Serdang soil series

The effects of environmental factors on bioactivity, persistence and mobility of picloram were studied in the laboratory and greenhouse using long beans (Vigna sinensis Endl. ex Hassk), as a bioassay species. Two soils were used, namely Selangor series (silty clay loam soil) and Serdang series (silty clay soil). The bioactivity of picloram (Tordon®) was inversely correlated with the organic matter content of the soil and increased with increasing herbicide concentrations. The half-life ofpicloram decreased from 33.1 to 24.1 days as soil temperature increased from 25°C to 35°C in the Selangor series, and from 28.1 to 17.7 days in the Serdang series soil. The degradation rate of picloram also increased with increasing moisture level in both soil series. However, picloram persisted longa in Selangor series soil than in Serdang series. Downward mobility through the soil profile was inversely related to the organic maller content of the soil. The quantity and frequency of simulated rain directly influenced the extent of leaching of the herbicide. Downward movement of picloram was greater in Serdang series which contains less organic matter but high sand than Selangor series longest available vessel

The Performance Evaluation of Lightweight Concrete Piles on UTHM's Soft Soil under Static and Dynamic Loading Tests

Light-weight concrete generally has low density and low strength compared with normalconcrete, the use of the lightweight concrete for piling is still very rare due to high porosityand underestimate the strength. This research was done to find out the performance of lightweight concrete piles (LCP’s) which were made by Palm Oil Clinker (POC) and FoamedConcrete (FC) and to compare their performance with normal concrete pile (NC).Conventional static load test (slow maintained load test, SM) using kenteledge system toobtain pile capacities were performed for those three type of piles (NC, POC and FC)embedded in soft soil at RECESS, UTHM, Batu Pahat. Performance of piles were alsoevaluated using Pile Driving Analyzer (PDA) in dynamic loading. The results shows closecorrelation between static and dynamic test results and the stresses of compression and tensileunder both loadings were within the allowable limit state thus, the application of LCP’s fordeep foundation on soft soil is feasible

Evidence for Allelopathic Activity of Mikania micrantha H.B.K. on Three Weed Species

Laboratory, greenhouse and field studies were conducted to determine the allelopathic potential of Mikania micrantha H.B.K. on the germination and growth of three weed species, A.systasia gangetica (L.) T. Anders., Chrysopogon aciculatus (Ritz.) Trin and Paspalum conjugatum Berg. Germination and fresh weight of all three weeds decreased progressively when exposed to increasing concentrations of aqueous leaf or root extract of Mikania. The phytotoxic effect of root extract on the radicle elongation of the test species was greater than that of leaf extract. The dry weight and rate of emergence of the bioassay species used were affected when Mikania debris (leaf or root) were placed on soil surfaces or incorporated into the soil. P. conjugatum emergence was strongly affected when Mikania (root orleaf) was incorporated into the soil. Soil collectedfrom the field where Mikania had been growing had no effecton the final germination of the three weed species. However, dry weights of A. gangetica and P. conjugatum were significantly reduced when grown in the Mikanilt-infested so

Influence of Seeding Rate on Growth Performance and Yield of Early Maturing Sorghum

Heavy grazing pressure in Tanzanian semi-arid rangelands coupled with climate change and variability has resulted into severe decline in forage production and changes in vegetation composition. To increase forage biomass production in the face of climate change and variability, climate resilient fodder crops such as early maturing sorghum have been recommended in arid and semi-arid regions. However, paucity of information on the best agronomic practices especially the optimal seeding rate and row spacing fostered the need to carry out research on growth performance and yield of early maturing sorghum. The experiment was conducted at Magadu Dairy Farm to assess the Influence of Seeding Rate on Growth Performance and Yield of Early Maturing Sorghum. The experiment adopted the Complete Randomized Design (CRD), where different seeding rate (such as 8kg/ha, 12kg/ha, 16kg/ha, 200kg/ha) were assigned randomly and replicated three times making a total of 12 subplots. The row spaces were also varied in reciprocal order with seeding rate (60cm in 8kg/ha, 50cm in 12kg/ha, 40cm in 16kg/ha and 30cm in 20kg/ha). Parameters collected include, number of plants germinated, circumference of the plant, Dry matter (DM) yield and height of the plants. The data were subjected to One Way Analysis of Variance (ANOVA) using SAS program of 2014 to analyse the effect of seeding rate on growth attributes and yield of early maturing sorghum. The study established the positive correlation of seeding rate and number of plant as well as plant heights. On the contrary, seeding rate was found to be inversely proportion to plant thickness and number of leaves per plant. The above ground biomass was found to increase with increasing seeding rate up to 22.20 tonnes per ha and slightly declined at the highest seeding rate. We recommend further studies on nutritive values and palatability of sorghum to livestock

A study of weed populations and their buried seeds in the soil of MARDI research station and at farmers' rice fields in Sungai Burung, Tanjung Karang, Selangor, Malaysia

A study of weed populations and their buried seeds before and after harvesting was carried out at the MARDI Research Station and at Farmers' Rice Fields, Sungai Burung in Tanjung Karang, Selangor. The results showed that the broadleaf weeds were the most dominant in the MARDI and Sungai Burung rice fields. Two species, namely Cyperus difformis (sedge) and Najas graminae (broadleaj) were the most dominant species in the MARDI and Sungai Burung rice fields respectively. The weed seed populations were similar in both rice fields. However, the weed seed counts before and after harvesting were different. In general, it was also found that the highest number of weed seeds in the soil was detected in the 0-5 cm layer of soil in both rice fields

Mechanism of paraquat resistance in crassocephalum crepidioides (Benth.) S. moore during immature stage

The mechanism of paraquat resistance in Crassocephalum crepidioides at the six-leaf stage was investigated. The extractable paraquat was not metabolized fly the leaf tissue in the resistant (R) and susceptible (S) biotypes. Therefore, differential metabolism does not appear to play a role in the mechanism of resistance. The S biotype absorbed 44% more 14Gparaquat than the R biotype. However, more than 98% of the absorbed 14G paraquat remained on the treated leaf of both biotypes. The difference in absorption had a negative correlation with the amount of epicuticular wax as well as the cuticle of leaf surfaces in both biotypes. The results of this study suggest that differential absorption may be a factor that accounts for resistance to paraquat at the six-leaf stage