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This review critically examines the various ways in which the mechanical properties of wood have been understood. Despite the immense global importance of wood in construction, most understanding of its elastic and inelastic properties is based on models developed for other materials. Such models neglect wood’s cellular and fibrous nature. This review thus questions how well models that were originally developed for homogeneous and effectively continuous materials can describe wood’s mechanical properties. For example, the elastic moduli of wood have been found by many authors to depend on the size of the test specimen. Such observations are incompatible with classical elasticity theory. There is also much uncertainty about how well elastic moduli can be defined for wood. An analysis of different models for size effects of various inelastic properties of wood shows that these models only approximate the observed behaviour, and do not predict or explain the scatter in the results. A more complete understanding of wood’s mechanical properties must take account of it being in some sense intermediate between a material and a structure.

The aim of this study is to help to create a healthier environment by measuring the noise levels in the furniture and lumber sectors of forest products industry. In this study, noise measurement for approximately 3 min has been conducted in 4 measurement spots in the side of the machinery, in the factory entrance and in full and empty state for each machinery; from 3 different chosen spots in enterprises producing lumber. Measurements have been recorded as 720, from each machine as 36 measurements, with the condition to be recorded every 5 sec for 3 min. For this purpose, noise measurements have been carried out in 17 workplaces producing lumber and results have been compared statistically. As a result of the obtained findings, it is understood that the noise levels of thickness machinery don't exceed the value for the upper limit stated in the regulations. However, vertical wood band sawmill and band saw machines have been observed to go over this limit. Besides, some factors of planning and multi slitting machine don't exceed this limit, some of them exceed. As a result, it has been conducted that when noise levels of machinery used in the lumber industry enterprises exceed the upper limit stated in the regulations, they can pose a serious threat to human health. Gumushane University, Gumushane (in Turkish)Gumushane University [17. B0116.02.01] This study was supported as scientific research Project (Project Number: 17. B0116.02.01), Gumushane University, Gumushane 2018 (in Turkish). WOS:000588261100009 2-s2.0-85096970676

Freshly cut 30-mm-thick wood disks of Scots pine, Caucasian elm, narrow-leafed ash, wild cherry, black walnut, and European alder with various natural grade defects were dried together in a radiofrequency-vacuum (RF/V) dryer. A mild four-step drying schedule at the maximum temperature of 45 degrees C and power density in the range of 1-2 kWm(-3)with an on-off control of RF radiation at the final step was used. The moisture content of the disks at the end of drying ranged from 10.6% to 13.4%. An almost uniform radial moisture gradient developed in the dried disks. The six wood species, however, exhibited variations in checking. The RF/V drying schedule used here was able to completely inhibit near-bark radial checking in all disks but pine and elm, whereas it failed to efficiently prevent V-cracking in pine and ash with a high mean tangential to radial shrinkage anisotropy (S-T/S-R). A strong positive correlation was also found between S-T/S(R)and the proportion of V-cracked disks. The occurrence of ring failure within the reaction wood-containing disks of walnut, pine, and elm was almost completely prevented by the drying schedule, but a significant correlation was observed between the pith eccentricity and V-crack length in the compression wood-containing disks of pine. All other natural defects, i.e., scar in cherry, bark pocket, double or triple pithing in walnut and elm, sound knots in pine, and roundness deviation, exhibited no statistically significant effect (p > 0.05) on check formation. College of Agriculture and Natural Resources at University of Tehran This work was financially supported by College of Agriculture and Natural Resources at University of Tehran. This study was carried out in Turkey during a research stay of the first author at Duzce University. We would like to thank Recep Sivrikaya Company in Duzce for allowing us to use the industrial RF/V kiln. WOS:000579695500001 2-s2.0-85092777335

The objective of this work was to identify, diagnose and characterize the sawmills in four municipalities in the State of Minas Gerais (Divinésia, Senador Firmino, Brás Pires and Dores do Turvo) that provide lumber for the industries in the Furniture Hub in Ubá, State of Minas Gerais. A semi-structured questionnaire with open questions, answered in loco and accompanied by a responsible person (interviewer), with information on the identification of the potentialities and fragilities of the local lumber sector as well as to know the raw material (logs), the wood split processes, the internal management, the qualification of the employees, the machinery, products, market and prospects of the sector in these municipalities. It was found that Eucalyptus wood is the most used. The diameter of the logs is shown as the factor that affects the yield in 100% of the analyzed sawmills, where cracking and variability of the logs are the main difficulties of working with the raw material. The lumber sector in the analyzed municipalities needs a greater qualification, both managerial and technical, to improve the activity. In addition, it is necessary to better organize the companies related to the lumber sector through associations and support from local entities and greater exposure of the products to the local consumers. The objective of this work was to identify, diagnose and characterize the sawmills in four municipalities in the State of Minas Gerais (Divinésia, Senador Firmino, Brás Pires and Dores do Turvo) that provide lumber for the industries in the Furniture Hub in Ubá, State of Minas Gerais. A semi-structured questionnaire with open questions, answered in loco and accompanied by a responsible person (interviewer), with information on the identification of the potentialities and fragilities of the local lumber sector as well as to know the raw material (logs), the wood split processes, the internal management, the qualification of the employees, the machinery, products, market and prospects of the sector in these municipalities. It was found that Eucalyptus wood is the most used. The diameter of the logs is shown as the factor that affects the yield in 100% of the analyzed sawmills, where cracking and variability of the logs are the main difficulties of working with the raw material. The lumber sector in the analyzed municipalities needs a greater qualification, both managerial and technical, to improve the activity. In addition, it is necessary to better organize the companies related to the lumber sector through associations and support from local entities and greater exposure of the products to the local consumers.

This study aimed to evaluate the mechanical properties determined in a 4-point bending test of beams made of lumber from which knots had been locally removed and the resulting loss replaced with sound wood. Three sets of beams were prepared, which differed in the number of layers/lamellas and the position of the lamellas from which edge knots were removed. All the lamellas used in the tests were subjected to a modulus of elasticity assessment. In addition to the distribution of defects, it determined the position of a given piece in the beam structure. The tests showed that high mechanical properties could characterise the beams produced in this way, i.e., a modulus of elasticity close to 12 kN/mm2 and a strength above 40 N/mm2, if the lamellas without knots were located below the outer tension lamella. Significantly better results were obtained when PUR glue was used in the inserts rather than MUF. In this case, beams with an improved outer lamella in the tension zone using semi-circular inserts glued with PUR glue had an average strength of 34.6 N/mm2.

The aim of the study was to evaluate how the specific cutting energy is influenced by the variation of the wood basic density in Eucalyptus spp. clones. Five clones, 10 years old, were used in the study: three hybrids of Eucalyptus grandis x Eucalyptus urophylla, one of Eucalyptus grandis and one of Eucalyptus urophylla. From each clone, five trees were cut down and divided into 2.0 m long logs. In two axial regions of the trunk (from 2.5 to 4.5 m and from 4.5 m to 6.5 m) the logs were cut into boards and reduced to specimens with dimensions of 660 x 110 x 21 mm. The basic density was determined by the hydrostatic method in two opposite wedges obtained from discs removed at 2.5, 4.5 and 6.5 m from the total height of the tree. To analyze the specific cutting energy, 10 specimens were selected for each axial region and clone. A frequency inverter was used to monitor the cutting process. Analysis of variance was applied to evaluate the specific cutting energy and the wood basic density. The results obtained appointed a significant difference between the woods of the clones for basic density and specific cutting energy. For the wood in the different axial regions, only the specific cutting energy was significant. Clone 1 required less specific cutting energy, as it was influenced by the lower basic density. In the 2.5 to 4.5 m axial region, a higher specific cutting energy was observed even with lower basic density. El objetivo del estudio fue evaluar la influencia de la variación de la densidad básica de la madera del clon Eucalyptus sobre la energía específica de corte. Se utilizaron cinco clones, tres híbridos de Eucalyptus grandis x Eucalyptus urophylla, uno de Eucalyptus grandis y uno de Eucalyptus urophylla, de 10 años de edad. De cada clon, se talaron cinco árboles y se trazaron sobre troncos de 2,0 metros, en dos regiones axiales del tronco (2,5 a 4,5 m y 4,5 m a 6,5 m), los cuales se partieron en tablas y luego se redujeron a especímenes con dimensiones de 660 x 110 x 21 mm. La densidad básica se determinó por el método hidrostático en dos cuñas opuestas obtenidas de los discos removidos a 2.5; 4,5 y 6,5 m de la altura total del árbol. Para el análisis de la energía específica de corte se seleccionaron 10 especímenes para las regiones axiales y clones. El monitoreo de los cortes realizados por el convertidor de frecuencia CW 08 (WEG). Se realizó análisis de varianza para la energía específica de corte y para la densidad básica de las maderas. Los resultados obtenidos mostraron diferencias significativas, al 5%, entre las maderas de los clones para las densidades básicas y energía específica de corte. Para las maderas en las diferentes regiones axiales, solo la energía específica de corte fue significativa. El clon 1 requirió menor energía específica de corte, siendo influenciado por la menor densidad básica. En la región de 2,5 a 4,5 m, se observó mayor energía específica de corte aún con menor densidad básica. O objetivo do estudo foi avaliar a influência da variação da densidade básica da madeira de clones de Eucalyptus na energia específica de corte. Utilizou-se cinco clones sendo três híbridos de Eucalyptus grandis x Eucalyptus urophylla, um de Eucalyptus grandis e um de Eucalyptus urophylla, com 10 anos. De cada clone foram derrubadas cinco árvores e traçadas em toras de 2,0 metros, em duas regiões axiais do tronco (2,5 a 4,5 m e 4,5 m a 6,5 m) que foram desdobradas em tábuas e depois reduzidas a corpos de prova com dimensões de 660 x 110 x 21 mm. A densidade básica foi determinada pelo método hidrostático em duas cunhas opostas obtidas nos discos retirados a 2,5; 4,5 e 6,5 m da altura total da árvore. Para a análise da energia específica de corte foram selecionados 10 corpos de prova para as regiões axiais e clones. O monitoramento dos cortes feito pelo inversor de frequência CW 08 (WEG). Foi feita a análise de variância para a energia específica de corte e para a densidade básica das madeiras. Os resultados obtidos apontaram diferenças significativas, a 5%, entre as madeiras dos clones para as densidades básicas e energia espefícia de corte. Para as madeiras nas diferentes regiões axiais, apenas a energia específica de corte se mostrou significativa. O clone 1 exigiu menor energia específica de corte sendo influenciado pela menor densidade básica. Na região de 2,5 a 4,5 m, observou maior energia específica de corte mesmo apresentando menor densidade básica.

This paper proposes a non-contact, online, rapid, and non-destructive measurement method of Pinus densiflora S.et Z. (Pinus densiflora) dimension lumber based on an algorithm of maximizing lumber recovery by minimizing the enclosure rectangle fitting area. The method takes the full influence of multiple factors, such as the difficulty in measuring large-size dimension lumber, conveying deflection, etc. into account. Image splicing, object and background segmentation, and lumber size measurements are carried out. Compared to other current algorithms, it can decrease the measurement errors and improve measurement efficiency. The problems of slow image segmentation, large-size lumber measurement, and conveying deflection are solved. Through measurement tests and error analysis, the measurement accuracy of the lumber size can reach 0.8 mm/m. This method meets the requirements of high-speed lumber production and lays the foundation for the development of a lumber detection and evaluation system.

Background One-handed backhand (OB) and two-handed backhand (TB) styles are commonly used in tennis, but only TB generates loadings on the non-dominant arm and a greater extension torque on the rear leg, leading to a greater axial torque involving rotation of the hip and trunk. The current study investigated whether those effects can further affect bone area (BA), bone mineral content (BMC) and density (BMD) in postmenopausal recreational tennis players. Methods BA, BMC and BMD of the lumbar spine, hip and distal radius were assessed using dual-energy X-ray absorptiometry in TB, OB, and swimmers’ group as a control (SG) (all participants self-reported for at least 5 years of exercise history, n = 14 per group). Muscular strength was assessed with a hand dynamometer. Among these three groups, the BA, BMC and BMD of distal radius and muscle strength were assessed using one-way ANOVA, and those of the lumbar region and the hip joint were tested by one-way ANCOVA. Results TB showed higher BMC and BMD for both lumbar spine and femoral neck than SG (all, p p p p Conclusion For postmenopausal women, performing two-handed backhand strokes, leads to higher BMC and BMD in the non-dominant arm, the lumbar region, and hips, indicating potential benefit to maintain bone health and strength. Whether this result leads to reducing the risk of osteoporosis needs to be investigated in further research.

S’hi descriuen diferents experiències de recuperació territorial a partir de resistències al model de producció forestal de monocultiu, en comunitats maputxes lafquentxes a Tirua, al litoral sud de la regió del Bio-Bio, Xile. El valor que cobren les resistències ve determinat perquè, en el període comprès entre 1997 i 2014, la proporció de superfície comunal coberta per plantacions forestals es va incrementar del 33% al 45,4%. A través del treball desenvolupat en el terreny durant els últims quatre anys, ha estat possible rescatar històries de resistències en diferents comunitats, com ara la comunitat Kellgko, a la localitat de San Ramón; la comunitat Lorenzo Quintrileo, a la localitat de Quidico; la comunitat Milla Raye, a la localitat de Las Misiones, i per últim, la comunitat Alto Primer Agua, The article describes several experiences of territory recovered by means of resistance to a monoculture model of forest exploitation in Lafkenche Mapuche communities in Tirua, in the southern coastal region of Bio-Bio, in Chile. The special meaning and value of such resistance derives from the fact that, in the period from 1997 to 2014, the portion of communal land used for forestry plantations rose from 33 percent to 45.4 percent. Thanks to the research work carried out on site for the past four years, it has been possible to rescue and collect stories of resistance in several communities, such as the Kellgko community in the municipality of San Ramon; the Lorenzo Quintrileo community in the town of Quidico; the Milla Raye community in the municipality of Las Misiones, and, finally, the Alto Primer Agua community., Se describen diversas experiencias de recuperación territorial a partir de resistencias al modelo de producción forestal de monocultivo en comunidades mapuches lafkenches de Tirúa, en el litoral sur de la región del Bío-Bío, Chile. El valor que adquieren las resistencias está determinado por el hecho de que, en el periodo comprendido entre 1997 y 2014, la proporción de superficie comunal cubierta por plantación forestal aumentó de 33% a 45,4%. A través del trabajo desarrollado sobre el terreno durante los últimos cuatro años, ha sido posible rescatar historias de resistencias en distintas comunidades, como lo son la Comunidad Kellgko en la localidad de San Ramón, la Comunidad Lorenzo Quintrileo en la localidad de Quidico, Comunidad Milla Rayen en la localidad de Las Misiones y finalmente, Comunidad Alto Primer Agua.

В статье рассмотрен вариант запатентованной конструкции пилорамы ленточной самоходной. Ленточная пилорама установлена на самоходное гусеничное средство и может быть доставлена в любое недоступное для колёсной техники место и вести заготовку обрезных досок и бруса различного вида. Общеизвестно, что при определённых условиях выгоднее готовую продукцию, в том числе пиломатериалы, вывозить с лесозаготовительного участка, а не доставлять кругляк к стационарным установкам. Постоянный рост цен на горюче-смазочные материалы заставляет искать пути снижения затрат на производство пиломатериала., The article considers a variant of the patented design of a self-propelled band sawmill. The band sawmill is installed on a self-propelled tracked vehicle and can be delivered to any place inaccessible to wheeled vehicles and make a stock of edged boards and beams of various types. It is well known that under certain conditions it is more profitable to export finished products, including lumber, from the logging site, rather than deliver the round timber to stationary installations. The constant increase in prices for fuel products makes us look for ways to reduce the cost of lumber production.

An integral calculation method (ICM) is presented for fully estimating the fiber orientation and fundamental physical and mechanical properties of softwood (SW) logs and lumber. The proposed ICM reproduces with great detail the most important anatomical features of SW, including annual rings, seasonal variations, main growth patterns (straight, spiral, and interlocked grain), and especially fiber distortions due to knot clusters for each annual ring. The failure load of the lumber has been predicted with an absolute error of 10.2%. In addition, the ICM has shown very strong robustness and high calculation speed as most of the calculations are performed analytically, and only one final simplistic computation is conducted by finite element analysis (FEA). This article describes the proposed ICM in detail and shows the initial verification with experiments. The ICM should contribute not only to lumber research and grading but also to research and optimization of logging and sawing industrial processes.

Při připravě metodiky pro snimkovani zkusebnich tělisek pro vidlickovou zkousku byly vyzkouseny dva způsoby snimani. Snimani pomoci kamery s makroobjektivem a snimani pomoci skeneru. Z jejich vzajemneho porovnani z hlediska casove narocnosti a kvality snimku vyplynulo, že snimani zkusebnich tělisek pomoci deskoveho skeneru s nasledným provedenim obrazove analýzy je pro daný experiment vhodnějsi.Obecný postup snimani a měřeni zkusebnich tělisek:- položeni folie a uhelniku na pracovni plochu skeneru,- nastaveni rozliseni skeneru,- vkladani zkusebniho vzorku,- snimani zkusebniho vzorku,- obrazova analýza zkusebniho vzorku.Výsledkem výse uvedene metodiky je soubor digitalizovaných dat pro vice než 4200 diskretnich bodů umožňujicich charakterizovat specificke tvary vice než 300 zkusebnich tělisek, ziskaných pro vidlickovou zkousku. Data svým rozsahem a charakterem umožňuji zahajeni praci na dalsi planovane etapě, kterou je porovnani těchto udajů s výstupy numerických modelů, vcetně celkoveho statistickeho srovnani.Pomoci digitalizace zkusebnich tělisek byla ziskana kvalitni zasoba pracovniho materialu a zjednodusil se problem dlouhodobeho skladovani klasických zkusebnich tělisek. Archivovane snimky, doplněne charakteristikou zkusebniho materialu, mohou být v připadě potřeby pomoci obrazove analýzy opětovně zkoumany.Lze předpokladat uplatněni metodiky snimani vzorků pro zjistěni stavu zkornatěni dřeva při řeseni aktualniho problemu - optimalizaci procesu suseni dřeva a sledovani výsledne kvality suseni.

The purpose of this study is to estimate the modulus of elasticity of green lumber with unknown moisture content (MC) by non-destructive measurement. This paper reports the results and statistical analysis of a large number of experiments. They indicate that the dynamic modulus of elasticity (DMOE) can be determined without knowing the MC. Mechanical grading with DMOE determined in this way is reliable and efficient with a correlation coefficient of 0.44, compared with a coefficient of 0.45 between MOR and DMOE of dry specimens. Thus the possibility of strength grading of Maritime pine (Pinus pinaster) at an early step in the industrial process is demonstrated with success.

Wood shrinks anisotropically as it loses hygroscopic moisture. While longitudinal shrinkage (parallel to the grain) is nearly negligible in normal wood, transverse shrinkage (across the grain) is significant and characterized as tangential and radial shrinkage. The application of average tangential shrinkage values to a rectangular cross section results in errors, especially for boards cut from near the center of the log. In addition, using a Cartesian coordinate system to calculate shrinkage cannot provide an estimate of cup. Calculating shrinkage and cup deformation using a previously developed model, this Excel model can provide a more realistic image of the final cross section and a more accurate estimate of shrinkage. The model is dependent on wood species, initial and final moisture contents, and location of the board within the log. This paper describes and illustrates uses of the model.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:21:54Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:34:45Z : No. of bitstreams: 1 2-s2.0-33750506319.pdf: 3116966 bytes, checksum: 14589d7ca8b0102c7e82104c43217314 (MD5) Made available in DSpace on 2014-05-27T11:21:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-07-01 The glued-laminated lumber (glulam) technique is an efficient process for making rational use of wood. Fiber-Reinforced Polymers (FRPs) associated with glulam beams provide significant gains in terms of strength and stiffness, and also alter the mode of rupture of these structural elements. In this context, this paper presents a theoretical model for designing reinforced glulam beams. The model allows for the calculation of the bending moment, the hypothetical distribution of linear strains along the height of the beam, and considers the wood has a linear elastic fragile behavior in tension parallel to the fibers and bilinear in compression parallel to the fibers, initially elastic and subsequently inelastic, with a negative decline in the stress-strain diagram. The stiffness was calculated by the transformed section method. Twelve non-reinforced and fiberglass reinforced glulam beams were evaluated experimentally to validate the proposed theoretical model. The results obtained indicate good congruence between the experimental and theoretical values. São Paulo State University UNESP, Rod. Com. Joao Ribeiro de Barros, 17900-000 Dracena, São Paulo São Carlos School Engineering USP, São Carlos, São Paulo São Paulo State University UNESP, Rod. Com. Joao Ribeiro de Barros, 17900-000 Dracena, São Paulo

Introduction :Myelomeningocele is a congenital defect in posterior arch of vertebra with herniation of cord and meanings ,which presence of hydrocephalus with high precalence complicates its treatment . This study tries to determine the frequency of hydrocephalus associated with myelomeningocele(MMC) in different levels of spinal column. Method: In a descriptive study during five years 1375-71childern under one year old with myelomeningocele admitted to Tabrize Medical Center of Imam Khomeini were followed for hydrocephalus . Results: From ninety-five patients of MMC ,56.8% developed hydrocephalus (68.4% male, 31.5% female ). Prevalence of MMC in each level of spinal column was: Lumbar 60%, Lumbosacral 31.5%,Thorasic and cervical 4.2% equally .developed in sixty eight percent of lumbar MMC,48% of lumbosacral ,25% of cervical and 0% of thoracic. Conclusion: More percentage of female gender with lumbosacral MMC developed hydrocephalus ,whereas in other level male gender more developed . Prevalence of hydrocephalus in this study was less than other studies .In contrast to other studies showed that our study lumbar and then lumbosacral MMC had more susceptibility to develop hydrocephalus.

This paper presents the results from an experimental test program conducted on commercially available oriented strandboard (OSB) panels and statistical analyses of the results. Standardised testing was used to determine the short-term behaviour of OSB/3 panels subjected to tension loading. A variety of thicknesses sourced from three different producers were used. Analysis of the results indicate that a quadratic expression in the form of sigma = a epsilon(2) + b epsilon provides the best description of the relationship between stress (sigma) and strain (epsilon) up to the point of failure. It has also been shown that the coefficients a and b of the quadratic regression equations are negatively correlated to each other. Anderson-Darling goodness-of-fit tests were conducted on the results for tension strength and modulus of elasticity (MOE). The results indicate that the tension strength and MOE come from populations that follow either normal or lognormal probability distributions.

Residential deck and balcony failures are preventable if the decks and balconies are maintained and inspected regularly. Inspection of in-service decks or balconies is not common and often is unregulated or building codes do not appear to be widely enforced. With every failure, the need for a comprehensive inspection manual for residential wood decks and balconies becomes more apparent. Research was conducted on inspection techniques, common deck and balcony construction methods, maintenance issues, decay detection and the evolution of the building code regulations on decks and balconies. Eight decks were inspected to find the extent of structural inadequacies and non-conformance with building codes. Using the information gathered from the research and inspections, a Manual for the Inspection of Residential Wood Decks and Balconies was written for professional inspectors and building officials. The manual includes recommended methods to prepare for inspection to preparation of final reports. It contains an appendix with information on the "pick test" for detecting early decay, information on adequate deck attachment, and a sample report for a complete deck inspection. Master of Science

An extensive characterisation of Spanish laricio pine, Subsp. Salzmannii (Pinus nigra Arn. Subsp. Salzmannii) lumber has been carried out. The forest area for this species accounts for 352.954 Has and the average production for 310.000 m3/year (roundwood with bark). The study of technological characterisation of Pinus nigra Arn. Subsp. Salzmannii lumber is focussed only on three (Region 6 «Alto Maestrazgo», Region 7 «Sistema Ibérico Meridional» y Region 8 «Cordilleras Béticas») of the ten Regions of provenance that the species has in Spain due to the special interest of those forests and because they accounts for the 70,57 % of the total area and the 95 % of the total production of sawnwood. A test sample with 107 trees from 11 different sampling zones has been selected. 2886 boards, 500 disks and a very high number of small clear test samples, coming from 507 logs, has been prepared and tested. All the tests were carried out according to standards. Drying ability and quality have also been studied. This lumber seems to be highly resistant, with a high level of extractives and with a pronounced level of warp when drying. This lumber also seems to be very appropriated for structural purposes. Se ha llevado a cabo un completo estudio de caracterización de la madera de pino laricio subespecie Salzmannii (Pinus nigra Arn. subsp. Salzmannii), especie que ocupa en España un total de 352.954 Has, siendo la producción de madera en rollo (c.c.) de 310.000 m3. El estudio de caracterización tecnológica de la madera de P. nigra Subsp. Salzmannii se centra sólo en tres (Región 6 «Alto Maestrazgo», Región 7 «Sistema Ibérico Meridional» y Región 8 «Cordilleras Béticas») de las 10 Regiones de procedencia distintas existentes para la especie, dado el especial interés de estas masas y por representar por sí solas el 70,57 % de la superficie ocupada por la especie en España y prácticamente el 95 % del aprovechamiento maderero regular y de calidad. Para ello se ha seleccionado una muestra compuesta por un total de 107 árboles procedentes de 11 zonas de muestreo distintas, de los que se han extraído 507 trozas. La muestra de ensayo estuvo compuesta por 2886 tablas de 2, 3 y 4 metros de longitud, 500 discos y un número muy elevado de pequeñas probetas libres de defectos. Todos los ensayos fueron efectuados según normas. La aptitud al secado y su calidad fueron también evaluadas. Los resultados obtenidos permiten concluir que esta madera es altamente resistente, con un contenido en extractivos elevado y una acusada tendencia a la deformación durante el secado, siendo muy apta para el trabajo estructural.

A nation-wide survey of hardwood sawmills was conducted in the fall of 1999. The objectives of the survey were to determine the differences between adopters and non-adopters of scanning and optimizing technology, identify the company expectations of scanning and optimizing technology, and model the adoption decision process for future scanning and optimizing technology. These objectives were chosen because timely information was not available on the hardwood sawmill industry, and even less was known about the overall state of technology with the industry. The survey consisted of a mail questionnaire which was sent to over 2000 hardwood sawmills. The questionnaire was used to collect demographic, equipment, and preference scale information on the hardwood sawmill industry. The second part of this project used the Analytic Hierarchy Process to model the adoption decision process for future scanning and optimizing technology in hardwood sawmills. Data was collected through personal interviews with two hardwood sawmill groups including adopters and non-adopters of advanced scanning and optimizing technology. The interviewee rated the importance of the decision factors in the adoption decision process. They also rated the influence of four sawmill departments on the adoption decision process. The results from the mail survey found that the average yearly lumber production was 7.6 million board feet per sawmill. The most common type of scanning and optimizing technology, headrig optimization, was only in use by 27 percent of the responding mills. Advanced scanning and optimizing technology such as edger-optimizers and trimmer-optimizers were only in use by 10 percent and 5 percent of the respondents respectively. Adoption decision factors for scanning and optimizing technology were rated. Improved raw material recovery and increased lumber revenues were the two most highly rated factors. Accuracy of grading was the most highly rated factor for automated grading systems. The adoption decision model found that production related issues were most important in the decision process and that the production department was the most influential of the sawmill departments. Overall, scanning and optimizing technology adoption within the hardwood sawmill industry is low. For those that have adopted advanced scanning and optimizing technology, production issues were the driving factors. Ph. D.

Letter concerning the cost of a building being built for poultry.

Correspondence concerning a poultry house being built.

Colloque avec actes et comité de lecture. internationale.; International audience; In the lumber industry, we can observe that commodity products prices fluctuate according to seasonal patterns. Nevertheless, it is believed by the industry that it is impossible to take advantage of this information for many reasons. Firstly, the fact that many different products are produced at the same time from the same material input (coproduction) makes it difficult to produce exactly and only what is needed. Secondly, equipment is already being used at 100% capacity all year long, so there is no room to increase production when product selling price increases. Finally, the belief is that keeping finished products in stock till the moment for the right price arrives would increase inventory holding cost too much. For these reasons, the typical sawmill produces using a "push" strategy and sells its production, without much consideration of yearly price fluctuation. We have developed a mathematical model that allows planning the sales and operations of a network of sawmills at the tactical level. Using that model, we were able to show it is in fact possible to modulate production and inventory levels to increase sales revenue. We generated a single plan which, if it had been used for each of the last twelve years, would have increased the gross margin generated by an average of 1,47% of sales revenue.

Colloque avec actes et comité de lecture. internationale.; International audience; This research addresses the problem of tactical planning in a lumber supply chain. It proposes a framework for incorporating together data from two software, which simulate harvesting operations and lumber production, into an optimization module called LogiOpt. Using this framework, decisions regarding harvesting, transportation, wood allocation and lumber production can be integrated. Although the idea of global optimization is not entirely new, the main challenge has always been to obtain the data required. With the proposed framework, simulation allows us to obtain the information needed. Thus, by rethinking the tactical planning process and making it focus on value rather than on costs, we provide an optimal solution to the tactical planner, helping him make better decisions. Experiments carried-out using industrial data from a large Canadian company indicate that many opportunities are lost because the planner focuses more on cost-related considerations. These results illustrate why the forest supply chain needs to be considered as a whole rather than by its individual components. They also show the potential of using both simulation and optimization together in order to capture those gains.