Modélisation numérique du chauffage par micro-ondes des membranes biocomposites.

En raison des contraintes environnementales et de la raréfaction des ressources fossiles de matières premières, des efforts de recherches considérables sont déployés pour développer de nouveaux matériaux plus écologiques. Dans ce contexte, les fibres de bois et les fibres végétales, en générales, offrent beaucoup de potentiel pour la fabrication de biocomposites thermoplastiques. Ces renforts naturels présentent plusieurs avantages par rapport aux renforts conventionnels : ressources renouvelables, faible masse volumique, faible coût, moins abrasif. Ainsi, dans le but d’améliorer les performances des biocomposites et d’élargir l’éventail d’applications possibles de ces nouveaux matériaux, un nombre important d’études concernent le développement de nouveaux processus de fabrication, de biocomposites et la mise en forme de produits biocomposites. Toutefois, les travaux sur le comportement thermique de ces matériaux sont insuffisants et particulièrement sur l’impact des micro-ondes sur le chauffage de ces nouveaux matériaux. Dans ce travail, une approche numérique basée sur la méthode des éléments finis est utilisée pour caractériser l’évolution de la température d’un groupe de biocomposites soumis à des micro-ondes. Pour ce faire, l’équation de conservation de l’énergie thermique couplée à deux différentes formulations de la source radiative à micro-onde a été considérée. De nombreuses simulations numériques ont permis de confronter et de valider les résultats obtenus vis-à-vis des résultats analytiques et expérimentaux issus de la littérature. Ensuite, une étude numérique a été réalisée sur l’impact des micro-ondes sur un groupe de biocomposites

Transfer RNA Genes Affect Chromosome Structure and Function via Local Effects

The genome is packaged and organized in an ordered, non-random manner and specific chromatin segments contact nuclear substructures to mediate this organization. Transfer RNA genes (tDNAs) are binding sites for transcription factors and architectural proteins and are thought to play an important role in the organization of the genome. In this study, we investigate the role of tDNAs in genomic organization and chromosome function by editing a chromosome so that it lacks any tDNAs. Surprisingly our analyses of this tDNA-less chromosome show that loss of tDNAs does not grossly affect chromatin architecture or chromosome tethering and mobility. However, loss of tDNAs affects local nucleosome positioning and the binding of SMC proteins at these loci. The absence of tDNAs also leads to changes in centromere clustering and a reduction in the frequency of long-range HML-HMR heterochromatin clustering with concomitant effects on gene silencing. We propose that the tDNAs primarily affect local chromatin structure that result in effects on long-range chromosome architecture

Sago enterprise / Hanani Omar... [et al.]

SAGO ENTERPRISE is a business that focuses on producing products based from the sago palm (Metroxylon sp.). Our products are sago flour and Tebalui and had certificated from Sabah Forestry Department. All of these products are high demand especially in northern Sabah because it is highly used on a tourism sector. Unfortunately, the producers of sago products is very limited suppliers and about only 3 suppliers around Sabah. For the reason, we produce sago products to local people and small holders. According to the Sabah's history (early 1940), sago has saving many of people around Kuala Penyu and Beaufort on Japanese colonization. At that moment, the local people don't have any source of food especially rice because all of food sources has been taken by Japanese soldiers. Nowadays, the sago palm became as a commercial plant that can give better profit for those who involve with these plant. This is because only several areas in our country get benefit from it. As we know, sago is also has a potential to be a substitute product for substituting the starch flour

IoT based dual axis solar tracker implementation for polycrystalline photovoltaic with energy storage

This project has been identified as IoT Based Dual Axis Solar Tracker Implementation for Polycrystalline Photovoltaic with Energy Storage that has two degrees of freedom that act as axes of rotation, both horizontal and vertical. Polycrystalline panel is great in both diffuse light and specular light and yet known for its minimal cost. This motorized servo-motor system based final year project is a self-orient the solar panel towards the maximum intensity of sunlight using Light Dependent Resistor (LDR) and hence, it will generate supply to the load. The main system that use to control the movement of motor and sense the LDR is Arduino Uno. This portable 10W solar project can be used anywhere at any time as its main concern to educate people of basic solar tracker concept aside to help supplying 5V Direct Current (DC) load. An Internet of Things (IoT) is therefore added as a feature for this project to monitor the performance of photovoltaic voltage through Blynk application in cell phon

Allelopathic effects of Batawali (Tinospora tuberculata) on germination and seedling growth of plants.

A study was undertaken to explore the effects of methanol extracts (100,50, 25, 12.5 and 6.25 g/l) from the dried powders of aerial parts of Batawali (Tinospora tuberculata) on emergence and initial growth of rice, radish, lettuce and carrot as represented by germination percentage, radical and hypocotyle length. Results indicated that both stem and leaves of Batawali markedly raised the suppression of germination and primary growth of all examined crops when plants were exposed to increasing the methanol extract concentrations from 6.25to 100 g/l of distilled water. The half-inhibitory concentrations that inhibit germination (ECg50), radicle (ECr50) and hypocotyle (ECh50) growth weredetermined for both the extracts. According to these values, an index (Re) was calculated in order to establish a ranking of the most sensitive plants and most effective extract. It was observed that the leaves extract was more active than the stem extract and caused the greatest negative effect on germination and early growth of plants. All tested plants differed in their sensitivity to T. tuberculata extracts. Higher reduction in plant growth parameters was observed in carrot. The tested extracts inhibited mainly the growth of radicle more than the growth of the hypocotyle and germination percentage in all examined crops, except carrot. According to the study, it could be concluded that T. tuberculata extracts had a significant herbicidal activity which depended on the extract concentrations, plant parts and the target crops

Allelopathic effect of methanol extracts from Tinospora tuberculata on selected crops and rice weeds

Herbicidal potential of aerial parts of Tinospora tuberculata on germination and seedling growth of seven test plant species, namely rice (Oryza sativa L.); two rice weeds, barnyardgrass (Echinochloa crus-galli L.) and weedy rice (O. sativa f. spontanea); and four vegetable crops, lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.), carrot (Daucus carota L.), and cucumber (Cucumis sativus L.) were evaluated. Six concentrations of methanol extract (3.12, 6.25, 12.5, 25, 50, and 100 g L−1) were compared with the control (distilled water). The rate of seed germination and the radicle and hypocotyl length of 7-day-old test plant seedlings were reduced as the concentration of extracts increased compared to the control. Generally, the degree of toxicity of extracts derived from the leaves was more than the extracts derived from the stem. Cluster analysis and the concentrations required for 50% inhibition (defined as EC50) of all parameters showed that radicle growth was more suppressed than germination and hypocotyl growth. Lettuce and carrot were observed as the most sensitive plants while rice showed the highest tolerance to both extracts. Moreover, the dicot target plants were affected more severely than the monocots when treated with leaf extract. The chemical composition of the T. tuberculata methanolic extracts was analyzed by a GC–MS system. A total of 92 and 22 constituents (not previously identified) were found in the leaves and stem, respectively. The results showed that 17 of the 92 components in the leaves, as compared to 4 of 22 compounds in the stem, are known as toxic compounds. These results suggest that T. tuberculata contains a significant source of plant growth inhibitors with potential for the development of future natural herbicide

Comparative phytotoxic effects of aerial and root aqueous extracts of Sida Cordifolia L. on germination and seedling vigour performance of Lettuce, tomato and carrot

A comparative study was conducted to see the effect of Sida cordifolia L. aerial and root extracts on seed germination and seedling vigour performance of Lacttuca sativa (Lettuce), Lycopersicon esculentum (Tomato) and Daucus carota (Carrot). Four treatments were prepared 50, 25, 10 and 0 g/l (control). The result showed a significant decrease in germination and growth in all the treatments and regardless of concentrations lettuce was observed to be more susceptible in all extracts. Leaf extract exhibited the highest phytotoxicity followed by root while shoot extract produced the least effect. Inhibition index showed decrease in growth appeared to be concentration dependent. Liquid chromatography mass spectrum analysis of leaf and root extracts revealed presence of aliphatic acids notably stearic and palmitic which may act as inhibitory agents

Phytotoxic interference of volatile organic compounds and water extracts of Tinospora tuberculata Beumee on growth of weeds in rice fields

Tinospora tuberculata Beumee is an aromatic shrub with pharmacological properties and belongs to the Menispermaceae family. We assessed T. tuberculata for its ability to suppress growth of weeds in rice fields. In seedling bioassays, the rate of seed germination and the radicle and hypocotyl lengths of barnyard grass, rice and weedy rice seedlings were reduced as the concentration of aqueous water extracts and volatile organic compounds increased compared to the control. In a glasshouse experiment, T. tuberculata leaf powder also exhibited effective reduction in the emergence and growth of weeds in rice fields. Applications at rates of 4 t ha−1 completely suppressed emergence of barnyard grass, sprangletop and smallflower umbrella. The chemical compositions of extracts and volatiles were analyzed by GC–MS and HS-SPME-GC–MS. The results showed that 7 of 43 components in the leaf aqueous extract, as compared to 5 of 15 compounds in the stem aqueous extract, are known to be toxic compounds. Moreover, eight main volatile organic compounds were identified, which accounted for 97 and 95% of the whole fresh and dry leaf volatiles, respectively. We observed qualitative and quantitative differences in the compounds present in the dry and fresh leaf. Confocal laser scanning microscope images showed that the volatile emissions and aqueous extracts also inhibited the main root diameter, and the number and elongation of root hairs of tested weeds in rice fields. These results suggest that T. tuberculata contains a significant source of plant growth inhibitors. Hence, it can be used as a mulch to suppress weeds in rice fields and for developing new herbicide based on phytotoxic compounds release by this plant

Phytotoxic interference of volatile organic compounds and water extracts of Tinospora tuberculata Beumee on growth of weeds in rice fields

Tinospora tuberculata Beumee is an aromatic shrub with pharmacological properties and belongs to the Menispermaceae family. We assessed T. tuberculata for its ability to suppress growth of weeds in rice fields. In seedling bioassays, the rate of seed germination and the radicle and hypocotyl lengths of barnyardgrass, rice and weedy rice seedlings were reduced as the concentration of aqueous water extracts and volatile organic compounds increased compared to the control. In a glasshouse experiment, T. tuberculata leaf powder also exhibited effective reduction in the emergence and growth of weeds in rice fields. Applications at rates of 4 t ha− 1 completely suppressed emergence of barnyardgrass, sprangletop and smallflower umbrella. The chemical compositions of extracts and volatiles were analyzed by GC–MS and HS-SPME-GC–MS. The results showed that 7 of 43 components in the leaf aqueous extract, as compared to 5 of 15 compounds in the stem aqueous extract, are known to be toxic compounds. Moreover, eight main volatile organic compounds were identified, which accounted for 97 and 95% of the whole fresh and dry leaf volatiles, respectively. We observed qualitative and quantitative differences in the compounds present in the dry and fresh leaf. Confocal laser scanning microscope images showed that the volatile emissions and aqueous extracts also inhibited the main root diameter, and the number and elongation of root hairs of tested weeds in rice fields. These results suggest that T. tuberculata contains a significant source of plant growth inhibitors. Hence, it can be used as a mulch to suppress weeds in rice fields and for developing new herbicide based on phytotoxic compounds release by this plant