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1
Yang, Deshan, Ming Xu e Zhongfan Chen. "Experimental study on the reinforcement methods and lateral resistance of mortise-tenon jointed traditional timber frames". BioResources 16, n. 2 (20 aprile 2021): 4039–51. http://dx.doi.org/10.15376/biores.16.2.4039-4051.
Testo completoAbstract (sommario):
In order to study the lateral resistance of reinforced traditional Chinese timber frames with mortise-tenon connections, three cyclic tests were conducted on one-bay mortise-tenon jointed traditional timber frames. Three reinforcement methods, i.e., steel angle strengthening, wood brace, and Timu, were studied. Seismic performances were evaluated according to the experimental phenomena and the test results. The failure mode, hysteresis curves, skeleton curves, curves of stiffness degradation, and energy dissipation capacity of the three specimens were analyzed based on the tests. The test results showed that the wood frames had good deformability. The stiffness degradation of the timber frame was severe at the initial loading stage; however, the degradation rate tended to decrease after the initial stage. In addition, the energy dissipation increased as the lateral displacement increased. The wooden frames with mortise tenon joints strengthened by steel angle, wood brace, and Timu can achieve good aseismic results. The study can provide a theoretical basis for seismic design and reinforcing methods of traditional timber structures.
2
Kuklík, Petr, Lukáš Velebil, Anna Gregorová e Petr Svora. "MONITORING AND PROTECTION OF TIMBER-CONCRETE BRIDGES". Acta Polytechnica CTU Proceedings 22 (25 luglio 2019): 57–61. http://dx.doi.org/10.14311/app.2019.22.0057.
Testo completoAbstract (sommario):
The majority of timber bridges for ordinary road traffic are often made as timber-concrete composite structures. Concrete slab is something like as umbrella for timber. The reason for problems in timber-concrete bridges is nearly always poor detailing for durability and neglected maintenance. Mainly all aspects of timber protection and maintenance should therefore be considered even during the planning phase of bridge. Paper deals with evaluation of timber properties, system of opto-fiber sensors for monitoring and diagnostics of mechanical stress of timber-concrete bridges, and degradation of timber due to UV radiation, atmospheric conditions and biological agents after application of photocatalytic materials on surface.
3
Majak, W. "Further enhancement of 3-nitropropanol detoxification by ruminal bacteria in cattle". Canadian Journal of Animal Science 72, n. 4 (1 dicembre 1992): 863–70. http://dx.doi.org/10.4141/cjas92-098.
Testo completoAbstract (sommario):
Ruminal fluid obtained from cattle was used to determine the effects of different diets and supplements on the in vitro degradation of 3-nitropropanol, the miserotoxin aglycone of certain Astragalus species such as timber milkvetch (Leguminosae). Nitroethane, an analog of the aglycone that is much less toxic to mammals, was effective as a supplement when given on alternate days. It enhanced the in vitro rates of nitropropanol degradation in all experiments, by 70–170%. In agreement, daily doses of timber milkvetch at a level equivalent to 3 mg nitropropanol kg−1 body weight also enhanced nitropropanol degradation, suggesting an adaptation to the aliphatic nitro group by ruminal bacteria. The forage protein content appears to contribute to the microbial efficacy and this was verified when diets were supplemented with soybean meal. The protein supplement increased nitropropanol degradation by 37–44% and, as expected, it also promoted cellulose digestion in vitro. The effect of nitroethane supplementation on the absorption of nitropropanol from the rumen was examined when treated and control groups were challenged with timber milkvetch. Plasma levels of 3-nitropropionic acid, the oxidized form of nitropropanol which is detected in the blood, were significantly reduced in response to nitroethane supplementation, and rates of nitropropanol degradation by ruminal microbes were concomitantly enhanced. These combined results further elucidate the factors that control and contribute to nitropropanol detoxification and suggest possible methods of prevention of timber milkvetch poisoning under rangeland conditions. Key words: Timber milkvetch, toxic plant, detoxification, 3-nitropropanol, ruminal bacteria, cattle
4
Banjade, Mani R. "Discourse and Discursive Practices Over Timber in Nepal". Journal of Forest and Livelihood 10, n. 1 (13 settembre 2013): 58–73. http://dx.doi.org/10.3126/jfl.v10i1.8601.
Testo completoAbstract (sommario):
Forest sector of Nepal is far from harnessing its economic potential, but witnesses a continuation of deforestation and forest degradation. This is largely because of the limited policy focus on the management of the most important forest product – the timber. Taking timber at the central stage in the debate on forest management, this paper examines the existing stakeholder relations, policy deliberations, programs and everyday practices in Nepal. This paper draws on the country’s policy, legal and regulatory documents, policy deliberations on forest governance, media analysis and everyday practices of forest management. These policies and practices are analysed in relation to environmental discourse, social practices and hegemony in forest sector governance. This paper shows that, while timber occupies a central stage in the government’s decisions, in most of forest-related contestations, and in everyday management decisions, timber management has received only secondary importance in the national forest policy and discourses. The analysis shows that since forest policy discourses have departed from timber, local communities and the government have lost significant incomes from the forest. The marginalization of timber in the policy discourse also encouraged deforestation and forest degradation especially through illegal logging and forest encroachment. DOI: http://dx.doi.org/10.3126/jfl.v10i1.8601 Journal of Forestry and Livelihood Vol.10(1) 2012 58-73
5
Entry, James A., Nellie M. Stark e Howard Loewenstein. "Timber harvesting: Effects on degradation of cellulose and lignin". Forest Ecology and Management 22, n. 1-2 (dicembre 1987): 79–88. http://dx.doi.org/10.1016/0378-1127(87)90097-1.
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Anshari, G. Z., M. Afifudin, M. Nuriman, E. Gusmayanti, L. Arianie, R. Susana, R. W. Nusantara, J. Sugardjito e A. Rafiastanto. "Drainage and land use impacts on changes in selected peat properties and peat degradation in West Kalimantan Province, Indonesia". Biogeosciences 7, n. 11 (4 novembre 2010): 3403–19. http://dx.doi.org/10.5194/bg-7-3403-2010.
Testo completoAbstract (sommario):
Abstract. Degradation of tropical peats is a global concern due to large Carbon emission and loss of biodiversity. The degradation of tropical peats usually starts when the government drains and clears peat forests into open peats used for food crops, oil palm and industrial timber plantations. Major properties of tropical peat forests are high in Water Contents (WC), Loss on Ignition (LOI) and Total Organic Carbon (TOC), and low in peat pH, Dry Bulk Density (DBD), and Total Nitrogen (TN). In this study, we investigated impacts of drainage and land use change on these properties. We collected peat samples from peat forests, logged over peat forest, industrial timber plantation, community agriculture, and oil palms. We used independent t-tests and oneway ANOVA to analyze mean differences of the research variables. We found that peat pH, DBD, and TN tend to increase. A significant decrease of C/N ratio in oil palm and agriculture sites importantly denotes a high rate of peat decompositions. Water contents, LOI, and TOC are relatively constants. We suggest that changes in pH, DBD, TN and atomic C/N ratio are important indicators for assessing tropical peat degradation. We infer that land use change from tropical peat forests into cleared and drained peats used for intensive timber harvesting, oil palms and industrial timber plantations in Indonesia has greatly degraded major ecological function of tropical peats as Carbon storage.
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Daňková, Jana, Tereza Majstríková e Pavel Mec. "Bonded Joints in Water-Repellent Timber Structures". Key Engineering Materials 714 (settembre 2016): 3–9. http://dx.doi.org/10.4028/www.scientific.net/kem.714.3.
Testo completoAbstract (sommario):
Water in liquid and gaseous form is the main factor which significantly affects degradation processes in the wood. The mechanism and rate of wooden degradation processes can be effectively influenced by appropriate methods and technologies for its protection. However new knowledge, based on the possibilities of application of modern physical and chemical analytical methods, confirms that most well-known and previously commonly used protective equipment damages wooden structure. Many chemical substances, which are included in preservatives such as organic and inorganic biocides, or also flame retardants, are declared to be environmentally unacceptable. Nowadays, environmentally friendly treatment technologies of wood have increased attention to the above reasons. Wooden treatment by silicones ranks among the technologies which repellent, fire resistant and corrosion effectiveness is demonstrated by many authors. This article presents results of the experimental study that deals with the mechanical properties of bonded joints in the wood treated by silicones.
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Soe, Khaing Thandar, e Youn Yeo-Chang. "Livelihood Dependency on Non-Timber Forest Products: Implications for REDD+". Forests 10, n. 5 (16 maggio 2019): 427. http://dx.doi.org/10.3390/f10050427.
Testo completoAbstract (sommario):
Deforestation and forest degradation are occurring continuously and posing serious threats to forests and people worldwide. In Myanmar, poor regulation and unsustainable extraction of non-timber forest products (NTFPs) is affecting millions of hectares of natural forests; overexploitation of forest resources is one of the main drivers of forest degradation. Although evidence shows that the extraction of NTFPs results in forest degradation, there have been few studies on what drives rural people to depend on NTFPs and how to address these drivers in terms of policies and measures. Policies and measures are nationally enacted policies and actions that countries undertake to address the causes of deforestation and forest degradation. This study identifies which factors determine the dependence on NTFPs in forest-dependent communities. From these factors, we derived policy implications for the main causes of overexploitation of NTFPs to provide suggestions for developing policies and measures in the design of national Reducing Emissions from Deforestation and Forest Degradation (REDD+) strategies. Focusing on the Taungoo District as a case of dependence on NTFPs by local communities, we conducted a qualitative and quantitative data collection procedure based on interviewing households in the local communities. NTFPs contributed the most to total household income and the main types of NTFPs exploited were charcoal making and bamboo selling. Households with lower education level, less agricultural land, less income from off-farm activities, lived under the poverty line or used only charcoal were more dependent on NTFPs in the study areas. Poverty and fuelwood usage were factors affecting NTFPs dependence for landowners while rice insufficiency, off-farm income and fuelwood usage most affected the NTFPs dependence for landless people. The results suggested that national strategies for REDD+ should take into account local features such as income opportunities and land tenure in order to make local people cooperate with the government to avoid deforestation and forest degradation.
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Parracha, João, Manuel Pereira, António Maurício, Paulina Faria, Daniel F. Lima, Marina Tenório e Lina Nunes. "Assessment of the Density Loss in Anobiid Infested Pine Using X-ray Micro-Computed Tomography". Buildings 11, n. 4 (17 aprile 2021): 173. http://dx.doi.org/10.3390/buildings11040173.
Testo completoAbstract (sommario):
The present study aims at evaluating the impact of anobiid damage on pine timber elements. Anobiid attack produces a diffuse damage of the elements with a set of tunnels in random directions and sizes, thus confusing quantification. Therefore, a method was developed based on X-ray micro-computed tomography (μ-XCT) to obtain, for naturally infested timber samples, an empirical correlation between lost material percentage (consumed by beetles) and timber apparent density (original, before degradation—OTD and residual, after degradation—RTD). The quantified density loss can then be used in further assessment of the structure. The results of the tests performed showed high correlation between original apparent density and lost material percentage (r2 = 0.60) and between residual apparent density and lost material percentage (r2 = 0.83), which confirms μ-XCT as a valuable tool to the required quantification. The loss of density results can be further applied on the definition of an assessment method for the evaluation of the residual strength of anobiids infested timber, thus contributing to reducing unnecessary replacement. The optimized procedure of the μ-XCT study for infested Maritime pine (Pinus pinaster) is presented and discussed in this article.
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Akapame, Clement Kojo. "The chase for legal timber: Developments in the commercial trade of timber in Ghana". Environmental Law Review 22, n. 3 (settembre 2020): 198–214. http://dx.doi.org/10.1177/1461452920934704.
Testo completoAbstract (sommario):
The quest for timber and timber resources and its corollary effects on forest degradation has in the last decade contributed to a series of concerted local and international interventions aimed at addressing the situation. These interventions have taken the character of domestic policies, international agreements and pacts and to some extent, domestic legislative reforms. The plethora of interventions have created a horde of laws and agreements with varying scopes and applications, multiple institutions with interlocked and overlapping responsibilities and uncoordinated and often undocumented practice in the commercial trade of timber. The focus of this article is to prod through the domestic and international legal and institutional architecture on the regulation of the trade of timber and timber resources. The article hopes to unearth the challenges in complying with these obligations and propose recommendations on the way forward.
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Zhou, Hai Bin, Chuan Shuang Hu e Jian Hui Zhou. "Thermal Degradation of Bending Properties of Structural Larch Wood". Advanced Materials Research 557-559 (luglio 2012): 1563–66. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1563.
Testo completoAbstract (sommario):
Wood is being used extensively in timber construction in China. It is important to understand its response when exposed to elevated temperatures. In fire-resistant design for timber construction, the main goal is to ensure that enough structural integrity is maintained during a fire to prevent structure collapse. To study the effect of temperature on bending strength (MOR) and stiffness (MOE) of solid clear wood from Chinese larch, a total of 108 samples with various target temperatures were tested in static bending under same temperatures to ensure the wood temperature to be sustained. The results indicated that exposure to sustained temperatures caused significant degradation of bending strength and stiffness. The degradation of chemical composition of larch wood happened after 170 °C and caused a serious drop in mechanical properties of larch wood after 225 °C. The bending strength and MOE of larch wood behaved negative linear relationship with temperatures before 100 °C.
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Sinha, Arijit, Kenneth E. Udele, Jed Cappellazzi e Jeff J. Morrell. "A Method to Characterize Biological Degradation of Mass Timber Connections". Wood and Fiber Science 52, n. 4 (28 ottobre 2020): 419–30. http://dx.doi.org/10.22382/wfs-2020-040.
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Ferro, Fabiane Salles, Julio César Pigozzo, Diego Henrique de Almeida, Felipe Hideyoshi Icimoto, Laurenn Borges de Macedo, Carlito Calil Junior e Francisco Antonio Rocco Lahr. "Nondestructive Evaluation of Timber Columns of a Capela Bridge in the State of São Paulo, Brazil". Advanced Materials Research 778 (settembre 2013): 258–64. http://dx.doi.org/10.4028/www.scientific.net/amr.778.258.
Testo completoAbstract (sommario):
After years of exposure in environmental conditions, the wood is subject to decay by chemical, mechanical, physical and biological agents. Consequently its physical and mechanical properties can be reduced, affecting their use. Timber used in bridge sustention columns is subject to intense decay process, mainly in outcrop area (area in contact to the ground), the most critical situation, because of the best combination of humidity e oxygen, factors that provide wood decay organisms. Decay process can be minimized with preventive maintenance, as wood impregnation with preservatives, before installation of the timber. After wood is installed, a periodical maintenance is necessary to conserve and prolong its life time. Thus, the aim of this study is to evaluate degradation occurred in timber columns used in Capela Bridge sustention, built with mixed system of wood and concrete, after 10-years-old of use. Located in Piracicaba - SP, Brazil, the bridge was made with Corymbia citriodora CCA-treated. The columns strength and degradation conditions were evaluated in 2 points with isntrumented driller. Point A was approximately 1,5 m of the ground and point B was in outcrop area. Instrumented driller results showed that all the columns, in both points, presented good strength and had no degradation level.
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Treu, Andreas, Katrin Zimmer, Christian Brischke, Erik Larnøy, Lone Ross Gobakken, Foued Aloui, Simon M. Cragg et al. "Durability and protection of timber structures in marine environments in Europe: An overview". BioResources 14, n. 4 (11 ottobre 2019): 10161–84. http://dx.doi.org/10.15376/biores.14.4.treu.
Testo completoAbstract (sommario):
Timber structures in marine applications are often exposed to severe degradation conditions caused by mechanical loads and wood-degrading organisms. This paper presents the use of timber in marine environments in Europe from a wood protection perspective. It discusses the use of wood in coastline protection and archeological marine wood, reviews the marine borer taxa in European waters, and gives an overview of potential solutions for protection of timber in marine environments. Information was compiled from the most relevant literature sources with an emphasis on new wood protection methods; the need for research and potential solutions are discussed. Traditionally, timber has been extensively utilized in a variety of marine applications. Although there is a strong need for developing new protection systems for timber in marine applications, the research in this field has been scarce for many years. New attempts to protect timber used in marine environments in Europe have mainly focused on wood modification and the use of mechanical barriers to prevent colonization of marine wood borers. The importance of understanding the mechanisms of settlement, migration, boring, and digestion of the degrading organisms is key for developing effective systems for protecting timber in marine environments.
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Yu, Ling Ling, Jie Jun Wang e Te Huang. "Mechanical Properties of Wood and Timber Bridge Evaluation". Applied Mechanics and Materials 587-589 (luglio 2014): 1381–85. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.1381.
Testo completoAbstract (sommario):
Wood possesses material properties that may be significantly different from other materials normally encountered in structural design. It is necessary for the engineer to have a general understanding of the properties and characteristics that affect the strength and performance of wood in bridge applications. This paper discusses the mechanical properties of wood, including elastics properties and strength properties. Timber bridge are often exposed to harsh environment conditions. Over time, this exposure can lead to deterioration. In turn, this deterioration may lead to a loss of structural integrity that is detrimental to the structure and its users. Timber structural elements are susceptible to degradation due to environmental and loading conditions. A variety of inspection techniques can be employed to locate damage and decay in timber members in order to maintain structural performance. Methods of non-destructive techniques for timber bridges are getting more and more important. This paper presents several non-destructive methods to timber bridge structures.
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Preklet, Edina, László Tolvaj, Satoru Tsuchikawa e Dénes Varga. "Photodegradation Properties of Earlywood and Latewood Spruce Timber Surfaces". Acta Silvatica et Lignaria Hungarica 17, n. 1 (2021): 9–20. http://dx.doi.org/10.37045/aslh-2021-0001.
Testo completoAbstract (sommario):
Spruce (Picea abies Karst.) samples were irradiated using an ultraviolet light emitter mercury vapour lamp. The examined specimen surfaces contained earlywood or latewood to determine the photodegradation properties of these two tissue types. The generated chemical changes were monitored by diffuse reflectance Fourier transformed infrared spectroscopy. The difference spectrum method was used to present absorption changes. The earlywood suffered considerably greater degradation than the latewood during the UV irradiation. Most of the lignin molecules in the examined surface layer degraded during the first 11 days of UV irradiation for both earlywood and latewood. Results demonstrated that two types of unconjugated carbonyls absorbing at 1705 and 1764 cm–1 wavenumbers were created during the photodegradation. Time dependence of the absorption changes showed correlation between the guaiacyl lignin degradation and the generation of unconjugated carbonyl group absorbing at 1764 cm–1 wavenumber.
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Amilien, Caroline. "Conflicting international policies in tropical timber trade". Environmental Conservation 23, n. 1 (marzo 1996): 29–33. http://dx.doi.org/10.1017/s0376892900038224.
Testo completoAbstract (sommario):
SummaryTrade in tropical timber, while a minor cause of deforestation in the tropics, can be a substantial factor in promoting forest degradation and deforestation. International organizations and conferences increasingly recognize that adverse environmental effects of international trade can be reduced through regulations and economic incentives. Three international agreements, the GATT, the CITES, and the ITTA, now affect the tropical timber trade and are here reviewed. Adopted at different times, they illustrate different philosophies, pursue different objectives, and develop contradictory trade policy perspectives. Legal conflicts among these agreements reduce their effectiveness, and mitigate a global objective of making international trade in tropical timber more responsive to environmental issues. Harmonization among the GATT, the CITES, and the ITTA, and collaboration among organizations in charge of managing these agreements, should be reinforced in order to establish a coherent and uniform policy for tropical timber trade.
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Kamath, Abhijith, Wolfgang Gard e Jan-Willem Van de Kuilen. "Biodynamic timber sheet pile walls: vegetation retaining structure". European Journal of Wood and Wood Products 78, n. 5 (settembre 2020): 1045–55. http://dx.doi.org/10.1007/s00107-020-01598-7.
Testo completoAbstract (sommario):
Abstract Timber sheet pile walls are widely used for the protection of stream banks in different parts of the world. However, there is a tendency to create more sustainable types of stream banks not only because exploitable wood is more difficult to obtain, but also because of disturbance to the natural habitat of plants and animals due to hard embankments. In the Netherlands alone, about 2500 km of engineered timber sheet pile wall embankments exist, primarily made with tropical hardwood, besides an even much larger amount of ‘non-engineered’ small-size timber-based embankments. As an alternative, the authors propose to use a mixed timber sheet pile-vegetation system, where locally available timber can be applied in combination with natural vegetation. Unlike the usual bioengineering scheme, vegetation is not seen as an element, which could replace the timber sheet piles. Instead, a new perspective is tested, where the vegetation is included as a ‘structural’ element which can even counteract the consequences of time-dependent biological degradation of the timber sheet pile. By doing so, both long-term durability as well as reliability of the stream bank is improved. A comprehensive design strategy was developed based on well-established sub-models from the literature on plant growth, root reinforcement as well as timber damage accumulation. The timber sheet pile wall-vegetation system is illustrated in an example case study. Preliminary analysis including only the mechanical reinforcement of vegetation shows that there is a decrease in moment and shear acting on the timber sheet pile with growth of the vegetation. Consequently, the damage accumulation due to load duration effects on the timber decreases and the service life of the system increases. Thus, using vegetation in combination with highly degradable timber could possibly negate the need for using hardwood timber, or more generally, save resources that are currently used for these structures.
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Sulistyo, Joko, Sri Nugroho Marsoem, Tomy Listyanto e Yus Andhini Bhekti Pertiwi Bhekti Pertiwi. "Sifat Ketahanan Api dan Degradasi Panas Tiga Jenis Kayu Dilapisi Arang Kayu Sengon". Jurnal Ilmu Kehutanan 14, n. 1 (1 luglio 2020): 28. http://dx.doi.org/10.22146/jik.57460.
Testo completoAbstract (sommario):
Kayu sebagai biomaterial memiliki sifat yang tidak menguntungkan yaitu kayu dapat terbakar. Kebakaran dalam rumah dengan kostruksi material kayu membahayakan keselamatan jiwa manusia. Upaya telah dilakukan dalam mencegah kebakaran dengan meningkatan daya tahan material kayu. Penelitian ini dilaksanakan untuk mengembangkan material tahan api berbasis karbon (CFR) dari arang kayu sengon. Efektifitas CFR dari arang sengon untuk meningkatkan ketahanan api pada kayu jati, meranti merah dan pinus dipelajari. CFR dibuat melalui pencampuran serbuk arang sengon berukuran 10 mesh dan perekat PVAC dengan perbandingan (60:40), kemudian dikempa pada suhu 80 °C dengan tekanan 70 MPa selama 15 menit sehingga diperoleh lembaran komposit karbon berukuran 4 mm x 18 cm x 18 cm. Kayu jati, meranti merah dan pinus yang dilapisi dengan lembaran CFR diuji ketahanan terhadap api melalui pengumpanan pada api selama 1500 detik berdasarkan metode ASTM E 69-02 dengan modifikasi. Lembaran CFR dari arang sengon efektif untuk meningkatkan ketahanan api ketiga jenis kayu. Keberadaan lapisan CFR pada permukaan kayu efektif berfungsi sebagai solid material penghambat yang mampu memblok panas dari api dan melindungi dari terjadinya degradasi material kayu, yang ditunjukan dengan persentase luas penampang melintang yang tidak terbakar pada jati CFR sebesar 68,6% yang lebih besar dibanding jati kontrol sebesar 57,9%, rendahnya persentase kehilangan berat pada kayu pinus CFR dan meranti merah CFR sebesar 50,56% dan 26,57% dibandingkan kontrolnya sebesar 76,98% dan 30,72%, dan perubahan berat yang relatif sama dengan kontrol pada kayu jati dan meranti merah sampai 700-1.160 detik. Fire Retardancy Properties and Thermal Degradation of Three Timber Species Overlayed by Sengon Wood CharcoalAbstractWood as biomaterial poses unfavorable property that is wood can burn. Fire disaster in wooden houses threaten human lifes. Efforts have been implemented to improve fire retardancy properties of timbers for wooden houses. This research was carried out to develop carbon-based fire-retardant materials (CFR) overlay on three timber species. The effectiveness of carbon-based fire-retardant material from sengon charcoal to improve fire resistance in teak, red meranti and pine timbers was studied. The CFR materials were prepared by mixing 10 mesh sengon charcoal powder and PVAC adhesive with a ratio (w/w) 0f 60:40 followed by a hot pressing at a temperature of 80 °C with a pressure of 70 MPa for 15 minutes resulting 4 mm x 18 cm x 18 cm carbon sheets. Teak, red meranti and pine timbers overlayed by CFR sheet from sengon charcoal were tested through feeding on fire for 1500 seconds based on ASTM E 6-02 method with a modification. CFR sheets from sengon charcoal were effective to improve the fire resistance of the three species of timbers. CFR overlayed on timber surface was functioned as solid barrier material which was able to block thermal from fire and protected timber from thermal degradation showing by lesser percentage of cross section unburning area on teak CFR i.e. 68.6% than that of teak control i.e. 57.9%, lower percentage of weight loss on pinus CFR and red meranti CFR i.e. 50.56% and 26.57% respectively comparing with the controls i.e. 76.98% and 30.72%, and similar values of weight change percentage between teak CFR and red meranti CFR with the control until 700-1,160 s.
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J.T Yeo, Kevin, e David E.C Yeoh. "Stiffness and Strength Degradation of Timber Concrete Composite under Fatigue Loading". IOP Conference Series: Materials Science and Engineering 713 (3 gennaio 2020): 012024. http://dx.doi.org/10.1088/1757-899x/713/1/012024.
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Zen, Kazuaki. "Degradation, Inspection, Maintenance and Repair of Timber in a Marine Environment". Zairyo-to-Kankyo 54, n. 12 (2005): 554–58. http://dx.doi.org/10.3323/jcorr1991.54.554.
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McBain, Adam, Futong Cui, Linda Herbert e John N. R. Ruddick. "The microbial degradation of chlorophenolic preservatives in spent, pressure-treated timber". Biodegradation 6, n. 1 (gennaio 1995): 47–55. http://dx.doi.org/10.1007/bf00702298.
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Suwito, D., Suratman e E. Poedjirahajoe. "The Covid-19 pandemic impact on indigenous people livelihoods in the peat swamp forest ecosystem in Central Kalimantan Indonesia". IOP Conference Series: Earth and Environmental Science 894, n. 1 (1 novembre 2021): 012023. http://dx.doi.org/10.1088/1755-1315/894/1/012023.
Testo completoAbstract (sommario):
Abstract Global tropical peat swamp forest ecosystems mostly are found in Indonesia. However, these unique yet fragile ecosystems are subject to deforestation and degradation due to forest fires and land conversion. Peat swamp forests are well known for their ecosystem services related to global climate mitigation because they store carbon inside and are very vulnerable to forest fires. Another direct function is providing various needs for the indigenous people livelihoods who live close to and in the areas. This study was conducted qualitatively to assess the forest utilization and the impact of the COVID-19 pandemic on the livelihoods of indigenous people. The study results show that the Dayak Ngaju Communities utilize the forest for timber, non-timbers, medicinal plants, foods, and religious culture. There is no significant impact of COVID-19 on forest product collection activities, but the pandemic impacts the marketing and sales of forest products. The marketing of fish and other non-timber forest products has been negatively affected due to decreased demand and limited transportation. On the contrary, the use, need, and demand for medicinal plants for the traditional medicine of COVID-19 is increasing significantly and improving local livelihoods.
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Musah, Munkaila, Javier Hernandez Diaz, Abiodun Oluseun Alawode, Tom Gallagher, Maria Soledad Peresin, Dana Mitchell, Mathew Smidt e Brian Via. "Field Assessment of Downed Timber Strength Deterioration Rate and Wood Quality Using Acoustic Technologies". Forests 13, n. 5 (12 maggio 2022): 752. http://dx.doi.org/10.3390/f13050752.
Testo completoAbstract (sommario):
Hurricane and tornado events cause significant damage to high-value timber in the United States each year. Forest managers and landowners are keenly interested in finding solutions to salvage and repurpose these downed timbers before they cause pest infestations and fire outbreaks, completely losing their value or increasing processing costs. To better understand the wood quality of the downed timber, we used acoustic waves techniques as a nondestructive testing approach to assess the wood degradation rate of downed trees and determine the extent of fracture and voids in the damaged regions. We periodically monitored the acoustic velocity of the downed trees for 12 consecutive months using a time of flight (TOF) acoustic method. Acoustic measurements were conducted using three different techniques—longitudinal, transverse, and off-set methods. Wood density, age, and the diameter at breast height (dbh) class measurement for southern timber (chip-n-saw for dbh 8″–11″ and sawtimber with dbh 12″ and up) were used as the predictive parameters of the downed trees. The results indicated positive relationships between dbh class, stand age, and acoustic velocity measurement (R2 > 65%). The TOF acoustic velocity was indicated to potentially separate higher-stiffness timber from lower-stiffness timber in a hurricane event for structural or non-structural applications. The regression coefficient from the repeated measurements indicated that both age and diameter class strongly impacted the acoustic properties of the downed trees (p-value ≤ 0.001). The sawtimber dbh class recorded a higher acoustic velocity compared to the chip-n-saw type. Fracture, voids, and massive decay in downed trees were detected beyond the visible inspection, features that often are identified by loggers in lower quality wood; however, TOF showed a weak response in picking up incremental deterioration due to changes in specific environmental factors that affected acoustic readings. This study showed that acoustic wave methods could potentially be used as a field evaluation tool for assessing the quality of downed trees.
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van de Kuilen, Jan Willem G., e Wolfgang Gard. "Damage Assessment and Residual Service Life Estimation of Cracked Timber Beams". Advanced Materials Research 778 (settembre 2013): 402–9. http://dx.doi.org/10.4028/www.scientific.net/amr.778.402.
Testo completoAbstract (sommario):
Service life modelling of cracked timber beams can be performed using modified damage accumulation models that describe the combined effect or long term loads (mechanical) and biological of physical wood degradation. The combined model allows for the estimation of residual service life and an analysis of crack development. The model can also be used to analyse safety factors that may need to be applied. Also, a sensitivity analysis can be performed for future risks. It is shown that the failure risk is very sensitive to the level of the applied loads, similar to time to failure analysis of non-degraded timber. Failure in timber structures occurs within a very short time frame. A practical case of cracked glulam beams is included in the paper.
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Yang, Qingshan, Chao Gao, Ke Liu, Yingming Zhu e Juan Wang. "Compressive Strength of Aged Timber Members in Traditional Building: Considering Differences in Heartwood and Sapwood". Applied Sciences 12, n. 15 (31 luglio 2022): 7719. http://dx.doi.org/10.3390/app12157719.
Testo completoAbstract (sommario):
This paper compares the parallel-to-grain compressive strengths of wood sample specimens with defects with those of the associated timber log samples. The Chinese fir (Cunninghamia lanceolata) was examined using the static test method. We analyzed the effects of sampling position along the radial direction of the log sample and the age of timber on the parallel-to-grain compressive strength. We then developed time-dependent strength models of the heartwood (HW) and sapwood (SW). These models can be used to evaluate the strength of an aged timber member, using only the service duration, without taking material samples. The degradation of compressive strength over time was then analyzed using an existing multivariate time-dependent model that includes the stress level. The failure strength of the HW was found to be close to that of the SW when at low stress levels. The estimates of the compressive strength of timber members based on these models were better than those recommended by the Chinese National Standard.
27
Vanpachtenbeke, Michiel, Jan Van den Bulcke, Joris Van Acker e Staf Roels. "Performance of wood and wood-based materials regarding fungal decay". E3S Web of Conferences 172 (2020): 20010. http://dx.doi.org/10.1051/e3sconf/202017220010.
Testo completoAbstract (sommario):
Due to the increasingly stringent energy efficiency requirements, timber frame houses are becoming more and more popular across Europe. Depending on the circumstances, timber frame walls might be exposed to high relative humidity or condensation conditions, leading to a risk of fungal degradation. In order to assess the durability of a timber frame construction in a reliable way, a clear view on the potential risk of fungal growth is essential. Various experiments are reported in literature to define the minimal moisture threshold for fungal decay, yet all very different in set-up and hence leading to contradictory conclusions. Therefore, the present paper aims at a contribution to a better understanding of the influence of moisture conditions on the onset and progress of wood decay in timber frame walls. Based on the information that is still lacking in international literature, a new test methodology has been elaborated within this work and is reported in this paper.
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Oyediji, Olubukola Tolulope, e O. A. Adenika. "Forest Degradation and Deforestation in Nigeria; Poverty Link". International Journal of Multidisciplinary Research and Analysis 05, n. 10 (21 ottobre 2022): 2837–80. http://dx.doi.org/10.47191/ijmra/v5-i10-35.
Testo completoAbstract (sommario):
Forests are the most diverse terrestrial ecosystems, housing a quite large majority of the world’s terrestrial species. It provides many social, economic, and environmental benefits. In addition to timber and paper products, forests provide wildlife habitat and recreational opportunities, it prevents soil erosion and flooding, provides clean air and water as well. Degradation and Deforestation occurs when changes happens which affects the characteristics of a forest negatively in such a way that the value and production of its goods and services decline or it is converted to an alternative permanent non-forested land use such as agriculture, grazing or urban development. These changes are caused by both direct and indirect causes with direct causes being human activities e.g agricultural expansion, road construction etc while indirect causes are economic growth etc. A positive correlation between the level of poverty and utilization of forest resources which leads to deforestation and exploitations of forest resources has been established, with an estimation of more than 90% of the 1.2 billion people living in extreme poverty dependence on forests for some part of their livelihood. Hence, degradation and loss of forests pose a grave threat to biodiversity. The result of degradation and deforestation include flooding, reduction in forest carbon storage, climate change etc. some perceived way forward to tackling this are poverty reduction programs, addressing land tenure matters , forest monitoring mechanism amongst others.
29
Gao, Zhongwei, Donghui Ma, Ziyi Wang, Xiaodong Guo, Shidong Fang e Zhitao Fei. "Investigation of the restoring force model of through-tenon and half-tenon of timber with a certain level of universality". BioResources 16, n. 3 (7 giugno 2021): 5313–28. http://dx.doi.org/10.15376/biores.16.3.5313-5328.
Testo completoAbstract (sommario):
A restoring force model of through-tenon and half-tenon joints was studied with a certain level of universality. To address the differences among data collected under different test conditions, test data collected via through-tenon and half-tenon joints were counted and fitted, and their similarities were then generalized. To better simulate the gap and stiffness degradation between the through-tenon and half-tenon joints, the skeleton curves frameworks were simplified into four phases, namely sliding, elastic, yielding, and failure. The normalized control parameters collected through the characteristics of the framework of through-tenon and half-tenon joints, as well as the different coefficients of strength degradation and stiffness degradation were calculated. The hysteretic rules of the restoring force model of through-tenon and half-tenon joints were developed. Through case study, the results show that the MAPE (mean absolute percentage error) and R2 (coefficient of determination) of experimental data in the references and simulated data of through-tenon are respectively 12.570% and 0.735, while those of half-tenon are respectively 11.763% and 0.772; and the restoring force model of through-tenon and half-tenon joints being constructed had a certain level of universality. The results demonstrated that the construction of refined finite element analysis model of Chinese ancient timber architectures can be simplified to a certain extent to meet the pressing time for seismic performance analysis of many ancient timber architectures. It provides researchers with an innovative pathway to enhance the efficiency of seismic performance analysis of ancient timber architectures.
30
Goodell, Barry, Jerrold E. Winandy e Jeffrey J. Morrell. "Fungal Degradation of Wood: Emerging Data, New Insights and Changing Perceptions". Coatings 10, n. 12 (11 dicembre 2020): 1210. http://dx.doi.org/10.3390/coatings10121210.
Testo completoAbstract (sommario):
Wood durability researchers have long described fungal decay of timber using the starkly simple terms of white, brown and soft rot, along with the less destructive mold and stain fungi. These terms have taken on an almost iconic meaning but are only based upon the outward appearance of the damaged timber. Long-term deterioration studies, as well as the emerging genetic tools, are showing the fallacy of simplifying the decay process into such broad groups. This paper briefly reviews the fundamentals of fungal decay, staining and mold processes, then uses these fundamentals as the basis for a discussion of fungal attack of wood in light of current knowledge about these processes. Biotechnological applications of decay fungi are reviewed, and an overview is presented on how fungi surmount the protective barriers that coatings provide on surfaces. Advances in biochemical analyses have, in some cases, radically altered our perceptions of how wood is degraded, and even the relationships between fungal species, while other new findings have reinforced traditional perspectives. Suggestions for future research needs in the coatings field relative to enhanced fungal and environmental protection are presented.
31
Corradi, Marco, Adelaja Israel Osofero e Antonio Borri. "Repair and Reinforcement of Historic Timber Structures with Stainless Steel—A Review". Metals 9, n. 1 (21 gennaio 2019): 106. http://dx.doi.org/10.3390/met9010106.
Testo completoAbstract (sommario):
Recent trends in the use of stainless steel profiles for repair and reinforcement of historic timber structures, after degradation due to biotic and non-biotic attacks, are discussed in this paper. These structural challenges can vary from inadequate load carrying capacity to complexities involved with choice of repair materials and techniques. Given the recurring requirements of conservation authorities in terms of reversibility of interventions and compatibility between historic and new materials, an increase in the use of non-invasive reinforcement materials and reversible techniques was observed. Subsequently, engineers and researchers have increasingly employed stainless steel alloys in retrofitting historic timber structures. This paper therefore presents the state of the art in the use of stainless steel profiles in retrofitting timber structural elements within historic structures. It includes a review of the development of the retrofitting methods and existing experimental studies on the mechanical behavior of timber structures reinforced with stainless steel. Finally, it presents a number of case studies and draws conclusions on current trends and practices based on reported studies.
32
Stoilova, Alina S. "Impact of the Prospective Roundwood Export Ban on Russian Timber Production". Journal of Siberian Federal University. Humanities & Social Sciences 14, n. 7 (luglio 2021): 1080–91. http://dx.doi.org/10.17516/1997-1370-0786.
Testo completoAbstract (sommario):
Illegal timber harvesting and trafficking is one of the most important economic and environmental problems in the Russian Federation. Illegal logging leads to degradation of forests and a shortage of timber in wood industries. One of the measures to counter illegal logging is the ban on the export of raw wood, which will take effect on January 1, 2022. However, such a measure will lead not only to control over the circulation of illegal timber, but also to a number of economic consequences. The impact of the ban on the inland market can be assessed using the point sectoral model of the forestry complex (PSM‑fc). The results of scenario calculations show that a ban on the export of raw materials can lead to a reduction in logging volumes and an increase in the share of products of deeper processing in exports
33
Barchia, Muhammad Faiz, Khairul Amri e Renra Apriantoni. "Land Degradation and Option of Practical Conservation Concepts in Manna Watershed Bengkulu Indonesia". TERRA : Journal of Land Restoration 1, n. 2 (24 febbraio 2019): 23–30. http://dx.doi.org/10.31186/terra.1.2.23-30.
Testo completoAbstract (sommario):
Watershed overcoming deteriorates in its function was indicated by increasing soil erosion and land degradation. The research aims were to determine and map critical land degradation levels and to chose options of practical conservation concepts in Manna watershed. The Manna watershed lays on 102°51'38.2" - 103°10'57.8" long, and 04°0'39.6" - 4°29'38.0" alt covering 72,899.9 ha. The analysis procedures to determine land degradation levels based on Ministry of Forestry Rule (No. P.32/Menhut-11/2009), Procedures of Technical Design on Forest and Land Rehabilitation in Watershed (RTkRHL-DAS). The results showed that the Manna watershed divided in three land uses functions namely protected forest, limited timber forest, and agricultural cultivated areas/settlement. The land starting overcome degradation in covered by 35,318.6 ha or 48,77% of the watershed based on digital mapping using ArcGIS 10.1 software. The lands that categorized the critical level of degradation covered 7,989.5 ha or 11,03% of the watershed, and classified in the high critical level were 169.8 ha or 0,23% of the watershed. Options of conservation practice on the degraded lands in the Manna watershed should implement agro-forestry models because of the physiographical landscape in this area covering by waving to hilly landforms. On the protected forest and limited timber forest should develop agro-forestry with collaborative approaches through social engineering and social forestry. Re-establishing land use of the Manna watershed based on functions of land is the wise options for the sustainable environmental concepts
34
Islam, M. A., S. M. S. Quli e Tahir Mushtaq. "Wasteland reclamation strategy for household timber security of tribes in Jharkhand, India". Journal of Applied and Natural Science 9, n. 4 (1 dicembre 2017): 2264–71. http://dx.doi.org/10.31018/jans.v9i4.1522.
Testo completoAbstract (sommario):
The study sought to examine the timber dependency on forests and evolve wasteland reclamation strategy to eliminate the forest dependency in Bundu block of Ranchi District in Jharkhand, India. Multi-stage random sampling technique was applied to select 164 tribal households from 9 sample villages. Data were collected using structured interviews and non-participant observations which were analyzed using descriptive statistics viz., frequency, percentage, mean and range. Results revealed that forests contributed maximum timber (136.36 m3 annum-1) followed by traditional agroforestry (69.09 m3 annum-1), community forestry (41.33 m3 annum-1) and homestead forestry (35.71 m3 annum-1). Timber extracted is mostly consumed in housing (124.66 m3 annum-1) followed by agricultural implements (82.71 m3 annum-1), furniture (35.25 m3 annum-1), carts/ carriages (17.60 m3 annum-1), fencing (10.23 m3 annum-1), cattle shed/ store house (9.10 m3 annum-1) and others (2.94 m3 annum-1). Forests were exposed to timber pressure of 136.36 m3 annum-1 (48.27%) posing ample deforestation and degradation. The strategy consisted of timber and bamboo plantations is designed which would secure 1065.60 m3 annum-1 of timber, 0.455 lakh annum-1 of bamboo culms, 568.26 tons annum-1 of bamboo leaf and agricultural products. The strategy would yield income of Rs. 34210.78 household-1 annum-1 and employment of 67.15 person-days household-1 annum-1. Financial viability of proposed interventions has been worked out by meticulous economic calculations of Net Present Value, Benefit Cost Ratio and Internal Rate of Return. The execution of strategy would eliminate the current unsustainable timber extraction, safeguard the future timber predicament and ensure environmental security.
35
Cachim, Paulo. "ANN prediction of fire temperature in timber". Journal of Structural Fire Engineering 10, n. 2 (10 giugno 2019): 233–44. http://dx.doi.org/10.1108/jsfe-06-2018-0012.
Testo completoAbstract (sommario):
Purpose Fire degradation is an extremely important risk that threatens timber structures. It is therefore normal that timber design codes include provisions for the design and verification of structures under fire loading. Eurocode 5 is no exception to this, but the simplified methods presented in the code show some inconsistencies, and the advanced method is not practical to use for design purposes. Artificial neural networks (ANNs) have the ability to model complex problems and have been used in a variety of construction engineering problems. They can learn from a subset of data, and then they can be used to predict the results for other input parameters. The purpose of this study is to present the possibility of the use of ANNs for the prediction of temperatures in rectangular timber cross sections, under fire exposure. Design/methodology/approach In this work, a multilayer feedforward ANN has been trained to predict the temperatures within a timber cross section, using as input the size of the cross section, the timber density, the time of exposure and the coordinates of the point within the cross section. Findings The results obtained clearly indicate that ANN can be used to predict the temperatures in a timber cross section subjected to fire. Originality/value ANNs have not been used for the prediction of temperatures in timber cross sections. The use of ANN makes the temperature prediction under a standard fire loading in a cross section extremely easy to implement in any code. These results can be used to calculate the strength of the elements after fire.
36
Yermán, Luis, Yuhao Zhang, Jiangwan He, Martin Xiao, Lisa-Mareike Ottenhaus e Jeffrey J. Morrell. "Effect of wetting and fungal degradation on performance of nailed timber connections". Construction and Building Materials 353 (ottobre 2022): 129113. http://dx.doi.org/10.1016/j.conbuildmat.2022.129113.
Testo completo
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Mather, Alexander. "Bad harvest? The timber trade and the degradation of the world's forests". Applied Geography 16, n. 3 (luglio 1996): 264. http://dx.doi.org/10.1016/0143-6228(96)83719-2.
Testo completo
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Qin, Shujie, e Na Yang. "Strength degradation and service life prediction of timber in ancient Tibetan building". European Journal of Wood and Wood Products 76, n. 2 (1 agosto 2017): 731–47. http://dx.doi.org/10.1007/s00107-017-1211-x.
Testo completo
39
Poudyal, Bishnu Hari, Tek Narayan Maraseni e Geoff Cockfield. "Implications of Selective Harvesting of Natural Forests for Forest Product Recovery and Forest Carbon Emissions: Cases from Tarai Nepal and Queensland Australia". Forests 10, n. 8 (15 agosto 2019): 693. http://dx.doi.org/10.3390/f10080693.
Testo completoAbstract (sommario):
Selective logging is one of the main natural forest harvesting approaches worldwide and contributes nearly 15% of global timber needs. However, there are increasing concerns that ongoing selective logging practices have led to decreased forest product supply, increased forest degradation, and contributed to forest based carbon emissions. Taking cases of natural forest harvesting practices from the Tarai region of Nepal and Queensland Australia, this study assesses forest product recovery and associated carbon emissions along the timber production chain. Field measurements and product flow analysis of 127 commercially harvested trees up to the exit gate of sawmills and interaction with sawmill owners and forest managers reveal that: (1) Queensland selective logging has less volume recovery (52.8%) compared to Nepal (94.5%) leaving significant utilizable volume in the forest, (2) Stump volume represents 5.5% of total timber volume in Nepal and 3.9% in Queensland with an average stump height of 43.3 cm and 40.1 cm in Nepal and Queensland respectively, (3) Average sawn timber output from the harvested logs is 36.3% in Queensland against 61% in Nepal, (4) Nepal and Queensland leave 0.186 Mg C m−3 and 0.718 Mg C m−3 on the forest floor respectively, (5) Each harvested tree damages an average of five plant species in Nepal and four in Queensland predominantly seedlings in both sites, and (6) Overall logging related total emissions in Queensland are more than double (1.099 Mg C m−3) those in Nepal (0.488 Mg C m−3). We compared these results with past studies and speculated on possible reasons for and potential implications of these results for sustainable forest management and reducing emissions from deforestation and forest degradation.
40
Navaratnarajah, Sinniah Karuppiah, Henpita Gamage Sushan Mayuranga e Somasundaraiyer Venuja. "Influence of Type of Sleeper–Ballast Interface on the Shear Behaviour of Railway Ballast: An Experimental and Numerical Study". Sustainability 14, n. 24 (7 dicembre 2022): 16384. http://dx.doi.org/10.3390/su142416384.
Testo completoAbstract (sommario):
The shear resistance at the sleeper–ballast interface of a ballasted track is an important contributor in maintaining track stability under faster and heavier axle loads where the ballast undergoes significant lateral sliding. Different types of sleeper–ballast interfaces based on the type of sleeper arrangements, such as concrete sleepers, timber sleepers, and under sleeper pads (USPs) attached to the concrete sleepers influence the lateral stability of railway tracks. Therefore, in this study the shear and degradation behaviour of ballast at concrete–ballast, timber–ballast, and USP–ballast interfaces were examined in the laboratory using large-scale direct shear tests under 60 kPa normal stress. The use of waste materials in the construction of civil infrastructure is gaining a lot of interest in the engineering community. Therefore, in addition to commercial USPs manufactured using raw materials, recycled USPs manufactured from granulates of end-of-life rubber tyres were also tested in this study. The discrete element modelling (DEM) approach was used to predict the shear behaviour of ballast at 30, 90, 120, 150, and 180 kPa normal stresses. The bonded particle model (BPM) was adopted in the DEM to simulate the effects of particle breakage during shearing. The results exhibited that both commercial and recycled USPs significantly improve the shear resistance at the sleeper–ballast interface while reducing particle degradation compared to concrete and timber sleeper interfaces.
41
Le e Tsai. "Experimental Assessment of the Fire Resistance Mechanisms of Timber–Steel Composites". Materials 12, n. 23 (2 dicembre 2019): 4003. http://dx.doi.org/10.3390/ma12234003.
Testo completoAbstract (sommario):
Hybrid structures known as timber–steel composites (TSCs) have been extensively studied due to their potential use as alternative construction materials that can satisfy demands related to sustainability. In addition to load capacity, fire resistance is a major consideration regarding the extensive use of TSCs. In this study, 12 specimens were tested using a glulam timber material covering cold-formed steel at the center. Specifically, the TSCs were fabricated from two timber blocks and an I-shaped steel core assembled using dowels or glue as a major structure. In order to use additional timber as a fire protection layer to protect a major structure by its charcoal produced after being burned, an additional timber with 5 cm in thickness was used to cover the major structure. The 1-h fire testing of TSC following the ISO 834-1 standard was applied, in order to achieve the potential application for a 4-story timber building. The results showed that temperatures at the steel flange increased by more than 300 °C for the final 5 min in 10 out of the 12 TSC specimens, indicating that the fire protection provided by the timber structure was not sufficient. The charcoal layer surpassing the extra timber was originally set and entered the steel structure of the TSC, which was expected to retain its physical qualities after a fire. Methods for evaluating the charring properties, based on the conventional method for wood and the standard specification set by Eurocode 5, were used to assess the structural degradation of TSCs. The conventional assessments showed a divergence from the actual performance of TSCs. Such variations demonstrated the limitations of models for conventional wood in assessing the structure of a TSC. A realistic assessment was conducted to expand knowledge related to this composite under destructive processes and provide fire reference values for the practical implementation of TSCs.
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Liu, Angela, e David Carradine. "Seismic bracing performance of plasterboard timber walls". Bulletin of the New Zealand Society for Earthquake Engineering 52, n. 2 (30 giugno 2019): 56–66. http://dx.doi.org/10.5459/bnzsee.52.2.56-66.
Testo completoAbstract (sommario):
The goal of this study is to develop a racking model of plasterboard-sheathed timber walls as part of the efforts towards performance-based seismic engineering of low-rise light timber-framed (LTF) residential buildings in New Zealand.
Residential buildings in New Zealand are primarily stand-alone low-rise LTF buildings, and their bracing elements are commonly plasterboard-sheathed LTF walls. It is an essential part of performance-based seismic designs of LTF buildings to be able to simulate the racking performance of plasterboard walls. In this study, racking test results of 12 plasterboard walls were collected and studied to gain insight into the seismic performance of plasterboard-sheathed LTF walls. The racking performance of these walls was examined in terms of stiffness/strength degradation, displacement capacity, superposition applicability and failure mechanisms. Subsequently, a mathematical analysis model for simulating racking performance of LTF plasterboard walls is developed and presented. The developed racking model is a closed-form wall model and could be easily used for conducting three-dimensional non-linear push-over studies of seismic performance of LTF buildings.
43
Baba, M. Y., M. A. Islam e P. A. Sofi. "Household dynamics and small timber consumption in rural Kashmir (J&K), India". Journal of Applied and Natural Science 8, n. 4 (1 dicembre 2016): 2021–28. http://dx.doi.org/10.31018/jans.v8i4.1081.
Testo completoAbstract (sommario):
The study examined the extraction and consumption pattern of small timber and its socioeconomic and forest resource determinants among the rural people in district Ganderbal of Kashmir. The results showed that the total extraction of small timber from different sources in the sample villages was 39.46 tons annum-1, which is mostly consumed in housing and roofing (39.63%) followed by cattle shed/ store house (15.25%), rural furniture/ packing cases (14.75%), agricultural implements (13.25%), fencing (12.50%) and others (4.62%). The total small timber demand was 47.88 m3 annum-1, which is mostly procured from agroforestry (42.57%) followed by forests (26.09%), homestead forestry (17.05%) and social/ community forestry (14.29%). The people were destitute with respect to socioeconomic attributes while they are well-off regarding forest resource characteristics. Correlation and multiple regression analysis established a robust relationship between small timber consumption and socioeconomic and forest resource parameters. The small timber flow from forests to the sample villages is excessive as compared to the national estimates, creating threats to the biodiversity conservation and ecological stability of the adjoining forests. The over-utilization of forest biomass by the local people is leading to degradation of forest resources and diminished biomass productivity, which in turn induce socioeconomic and livelihood stress. Therefore, some alternative interventions are essential to be implemented efficiently to keep pace with current development and future challenges.
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Pandit, Bishnu Hari, e Gopal B. Thapa. "A tragedy of non-timber forest resources in the mountain commons of Nepal". Environmental Conservation 30, n. 3 (settembre 2003): 283–92. http://dx.doi.org/10.1017/s0376892903000286.
Testo completoAbstract (sommario):
There is increasing degradation of non-timber forest products (NTFPs) in the mountains of Nepal. It has been proposed that different components of a common property resource (CPR) do not undergo degradation at the same rate, as they are not managed in the same way under different types of property rights regimes. To examine this, information was collected through a survey of 324 households, community resource assessment ranking and group discussion in a small mountain watershed of Nepal. The study analysed NTFP collection and management practices under government and community forest management systems, and impact of these practices on the status of forest and NTFPs. The analysis based on people's perception revealed that NTFPs were being depleted more rapidly than timber components in both types of forest. The pace of depletion was, however, considerably lower in community forests, as these forests were accessible only to the relevant forest user group members. Depletion of NTFPs was due primarily to the lack of proper institutional arrangements, including the lack of a comprehensive government policy framework, for sustainable use and management of NTFPs.
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Davis, Kent, Scott Leavengood e Jeffrey J. Morrell. "Performance of Exterior Wood Coatings in Temperate Climates". Coatings 11, n. 3 (11 marzo 2021): 325. http://dx.doi.org/10.3390/coatings11030325.
Testo completoAbstract (sommario):
Wood used in exposed exterior applications degrades and changes color due to weathering. Expanded use of mass timber is resulting in architects increasingly designing structures with wood in exterior exposure. Coatings can reduce the effects of weathering and prolong the visual characteristics of wood. However, coating performance depends on a variety of factors including the blend of resins, oils, pigments, and binders. Coating manufacturers often claim superior performance for products, but data directly comparing different coatings on different species is rarely publicly available. Premature coating failure increases long-term building maintenance expense while potentially enhancing biological degradation and reducing service life. This study compares the performance of 12 exterior wood coatings on 5 wood species. Performance was evaluated according to changes in the components in the International Commission on Illumination (CIE) L*a*b* color space of images taken at 6-month intervals over 18 months of the wood samples. The analysis was performed using Welch’s ANOVA, Games-Howell pairwise comparisons tests, and a clustering procedure using distances between each pair of groups means for the 18 months ΔL*, Δa*, Δb* values. Most of the coatings lost their protective effects within 1 year of exposure due to combinations of biological and ultraviolet radiation (UV) degradation illustrating the difficulty of protecting timber in exterior exposures. This study provides a guide for users wishing to specify coatings for exposed wood in mass timber structures.
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Praveena, Dr S. Mary, B. Akshaya, BB Devipriya, C. Divya e K. Mirudhula. "FOREST FIRE DETECTION USING DRONE". International Journal of Engineering Applied Sciences and Technology 6, n. 7 (1 novembre 2021): 110–13. http://dx.doi.org/10.33564/ijeast.2021.v06i07.018.
Testo completoAbstract (sommario):
Forest fires are a major reason behind forest degradation and have wide ranging adverse ecological, economic and social impacts, including loss of valuable timber resources, degradation of catchment areas, loss of biodiversity and extinction of plants and animals. In the recent times forests of Amazon and Australia faced a serious a threat to both wildlife and mankind. It also caused an enormous loss to both the countries. This paper describes early detection of fire by sectionally dividing the forest for efficient monitoring. The flame sensor is used to detect fire and a drone is employed as a mobile object which monitors the respective section. This drone travels from one pole to a different every alternate hour and gets charged while it's on a pole, because the pole has solar array. There is a timer also used at the poles which indicate the time of arrival and time of departure of the drone. The transponders are accustomed receive and transmit the signals. By this detection the nearby department of local government can get the precise location of the wildfire and early measures will be taken accordingly
47
Ellefson, Paul V., e Patrick D. Miles. "Protecting Water Quality in the Midwest: Impact on Timber Harvesting Costs". Northern Journal of Applied Forestry 2, n. 2 (1 giugno 1985): 57–61. http://dx.doi.org/10.1093/njaf/2.2.57.
Testo completoAbstract (sommario):
Abstract Costs were evaluated for six forest practices designed to prevent degradation of water quality from 18 timber harvesting operations in the Midwest. Net revenue reductions ranged from 1.2% for redesigning landing and skid trail locations to 26.4% for meeting buffer strip requirements. Nine operations were profitable with application of all six practices. Limited production function information hinders such analyses. North J. Appl. For. 2:57-61, June 1985.
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Macchioni, Nicola, Massimo Mannucci, Roberto Olmi, Sabrina Palanti e Cristiano Riminesi. "Microwave Reflectometric Tool for Non-Destructive Assessment of Decay on Timber Structures". Advanced Materials Research 778 (settembre 2013): 281–88. http://dx.doi.org/10.4028/www.scientific.net/amr.778.281.
Testo completoAbstract (sommario):
Timber structures can be degraded during their life both by structural problems and, mainly, by biological degradation factors like fungi, and insects (Coleoptera and termites). The occurrence of these biodegradation agents leads, in the absence of appropriate maintenance interventions, to the loss of their structural integrity. Furthermore, if these biological agents decay old buildings, the loss of mechanical resistance of timber structures can be added to loss of cultural heritages. Just in these contexts an early evaluation of decay is crucial to design remedial treatments and a less invasive restoration intervention. This work presents a new microwave diagnostic system for the in situ evaluation of timber structures based on microwave reflectometry, i.e on the measurement of the microwave reflection coefficient as a function of frequency. The continuous-wave (CW) microwave signal is launched by a double-ridged antenna, which also measures the wave reflected by the material under investigation. The measurement system allows diagnosing the effects of biodegradation during a first quick survey in a non-destructive and non-invasive manner. Measurements on laboratory models demonstrated the feasibility of the method. Results obtained on timber beam sections, compared with the findings of traditional investigation methodologies, demonstrate the potentiality of microwave reflectometry, suggesting its usefulness for decay detection and as a support to invasive diagnostic tools.
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Perria, Elena, e Mike Sieder. "Six-Steps Process of Structural Assessment of Heritage Timber Structures: Definition Based on the State of the Art". Buildings 10, n. 6 (8 giugno 2020): 109. http://dx.doi.org/10.3390/buildings10060109.
Testo completoAbstract (sommario):
Each construction material deals with specific mechanical properties, their distribution, damage mechanisms, and degradation processes. Therefore, each material requires a particular assessment approach in order to derive a reliable description of the residual performance of the structure, correctly remove the cause of damage, and proceed with the correct design of interventions. The aims of this paper are, first, the definition of a process of assessment and retrofitting of existing timber structures, both for engineered and heritage/traditional timber structures, and second, a comparison between the defined assessment process and its contents, and the content of existing guidelines, codes, and standards. In order to gain a definition of the process of assessment and retrofitting of existing timber structures, the content of scientific papers and articles was analyzed, and on this basis, an assessment process with six main steps and three milestones was developed. The content of the guidelines, codes and standards was afterwards analyzed basing on this six-steps assessment process. From a comparison among the current literature, guidelines, codes, and standards, interesting results emerged that gave us a picture of the European knowledge and interests on the assessment of existing timber structures. Not only agreement, but also discrepancies, variances, and incongruities were identified as possible topics for future research.
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Ananda, Komang Dean, Pande Komang Suparyana e Maftukhakh Hilmya Nada. "PERAN BALAI PENGELOLAAN HUTAN MANGROVE WILAYAH I BALI DALAM PENGOLAHAN HASIL HUTAN MANGROVE BERBASIS PEMBERDAYAAN MASYARAKAT LOKAL". SOCA: Jurnal Sosial, Ekonomi Pertanian 13, n. 3 (31 dicembre 2019): 331. http://dx.doi.org/10.24843/soca.2019.v13.i03.p04.
Testo completoAbstract (sommario):
Mangrove degradation is increasing along the proliferation of purposely land conversion. The utilization of the products of mangrove forests are oriented to the timber. Processing of mangrove products that have economic value should be a form of mangrove conservation and sustainability. Balai Pengelolaan Hutan Mangrove (BPHM) Wilayah 1 Bali, has become a center to processing mangrove forest products, especially non-timber products in Mangrove Tahura Ngurah Rai, which empowers local communities with skill training to process mangrove products into the economic value products. This research was carried out at the Mangrove Tahura Ngurah Rai. The method used is by observing mangroves by random sampling which will then be harvested based on the characteristics of ready harvest and harvest time. Mangroves that have been harvested, among others Sonneratia caseolaris, Bruguiera gymnorrizha, and Xylocharpus granatum. Those mangrove products will be processed into products such as syrup, soap, dodol, flour, rice, and scrubs. The processing of non-timber products is done through empowering local communities. The utilization of mangroves is more focused on the non-timber of forest products by utilizing mangrove fruits and leaves, ecotourism utilization, and silvofishery. BPHM I. Bali has an important role in maintaining the sustainability of the Mangrove Tahura Ngurah Rai.