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Effect of Incorporation of Chips and Wood Dust mahogany on Mechanical and Acoustic Behavior of Brick Clay

Journal of Building Construction and Planning Research 2014年第3期2卷 198-208页

作者： Gilbert Ganga Timothee Nsongo Hilaire Elenga Bernard Mabiala Thomas Tamo Tatsiete Nzonzolo Ecole Nationale Supérieure Polytechnique (ENSP) Université Marien Ngouabi Brazzaville Congo Faculté des Sciences et Techniques Université Marien Ngouabi Brazzaville Congo Ecole Nationale Supérieure Polytechnique (ENSP) Université de Yaoundé I Yaoundé Cameroun

An experimental study was carried out on bricks using local materials in order to take into account the waste wood management to protect the environment and to reduce the cost of the habitat. Chips and sawdust were built-in clay bricks in order to study their influence on the compressive strength, Young’s modulus and the speed for soundproofing. Testings in compressive strength were made on the parallelepiped clay bricks, stabilized with different percentages of cement, with incorporation to various percentages of sawdust or wood chips (mahogany), using a universal press. Young’s modulus was measured from the speed of sound by the ultrasonic method. The results obtained show that the incorporation of mahogany tree chips in the stabilized brick at 8% of cement, does not have much effect on the compressive strength. It was found that the incorporation of chips or sawdust on the clay brick, does not improve the compressive strength. The Young’s modulus decreases with increasing content of sawdust and practically remains constant regardless of the content of chips at 4% and 6% of cement. The clay brick mixed with 8% of mahogany sawdust can be an acoustic barrier.

关键词： Effect of Incorporation of Chips and Wood Dust mahogany on Mechanical and Acoustic Behavior of Brick Clay

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Silvicultural Systems for Restoration of mahogany in Degraded Landscapes in Africa: Influence of Mixed Rainforest Plantation on Growth and Pest Damage

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Open Journal of Forestry 2014年第4期4卷 414-425页

作者： Emmanuel Opuni-Frimpong Nana Yaa Nyarko-Duah Ebenezer J. D. Belford Andrew J. Storer Faculty of Biosciences Kwame Nkrumah University of Science and Technology Kumasi Ghana Forestry Research Institute of Ghana Kumasi Ghana School of Forest Resources and Environmental Science Michigan Technological University Townsend USA

African mahogany, one of the world’s most valuable timber species is threatened by over-exploitation in natural forests and failure of plantations due to attacks by the shoot borer Hypsipyla robusta. Mixed-species plantations has been reported to be an effective component of integrated pest management of major pest in other crops;but there is very limited empirical data on its use for managing Hypsipyla in mahogany mixed stands in West Africa. The aim of this study was to assess the effect of mixed-species stands as management intervention, on the growth of Khaya grandifoliola and Khaya ivorensis in relation to Hypsipyla robusta attack in a 10 ha experimental plantation in the wet evergreen forest type in Ghana. Khaya grandifoliola recorded faster growth than Khaya ivorensis in this forest type though the later naturally grow in this forest type while the former is introduced from the dry forest. Two years after planting, diameter and height growth were greater in the mixed-species stand than the pure stands for K. grandifoliola and K. ivorensis. Hypsipyla damage was less in the mixed stands of both K. grandifoliola and K. ivorensis compared to the pure stands, with the 20% and 10% Khaya mixed stand recording the lowest attack in both species. It can be recommended that mixed stands of the two Khaya species at 20% or lower Khaya density might be ideal for reducing the levels of Hypsipyla attack in this type of forest.

关键词： African mahogany Hypsipyla robusta Mixed Plantation Planting Density Khaya Species

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Eco-Friendly Pest Control in Cucumber (<i>Cucumis sativa</i>L.) Field with Botanical Pesticides

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Natural Resources 2013年第5期4卷 404-409页

作者： Abul Kalam Azad Arif Sardar Nilufa Yesmin Mizanur Rahman Saiful Islam Department of Crop Science and Technology University of Rajshahi Rajshahi Bangladesh Institute of Environmental Science University of Rajshahi Rajshahi Bangladesh

A field experiment on eco-friendly pest control in cucumber (Cucumis sativa L.) field was conducted at Rajshahi University during April, 2011 to June, 2011 with eight botanical pesticides prepared from the leaves and seeds of Bangladeshi plants. These botanicals are mahogany seeds, (Swietenia mahagoni), chirata leaves (Swertia chirata), jute seeds (Corchorus olitorius L.), garlic (Allium sativum L.), marigold leaves (Tagetes erecta) and carrot leaves (Daucus carota). One control treatment without botanicals was maintained during this experiment where only water was sprayed. Out of these botanicals, a less number of insect attacks on cucumber leaves (1.33 ± 0.19) were found in combined treatment of mahogany and chirata whereas a high number of insect attacks were observed in combined treatment of garlic and jute seed (5.89 ± 0.40) and control (4.66 ± 0.33). Individual application of chirata extract also showed good protection of cucumber leaves (1.67 ± 0.19) from insect attack. A smaller number of leaves perforations were found in the combined treatment of mahogany and chirata (3.44 ± 0.29) compared to control (14.22 ± 1.05). Chirata extract also showed good performance (4.00 ± 0.19) against leaves perforation of insect. Besides the pest control, botanical pesticides also have enormous effect on plant growth. The tallest cucumber plant was observed in the combined treatment of mahogany and chirata (469.00 ± 63.51 cm) and shortest in garlic treatment (84.56 ± 15.24 cm). The cucumber production was also high in combined treatment of mahogany and chirata (1863.33 ± 196.32 g) compared to control (1260.00 ± 501.63 g). From this study, it is found that combined application of mahogany and chirata extract not only showed good protection of cucumber plant from insect attack but also increased the cucumber production. Therefore, we conclude that farmers should use botanical pesticides from mahogany seeds and chirata leaves instead of toxic chemical insecticides for controllin

关键词： Cucumber Chirata mahogany Extract Eco-Friendly

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