scholarly journals Evaluation of Low-Grade Yellow-Poplar (Liriodendron tulipifera) as Raw Material for Cross-Laminated Timber Panel Production

2021 ◽  
Vol 72 (1) ◽  
pp. 1-10
Author(s):  
Rafael da Rosa Azambuja ◽  
David B. DeVallance ◽  
Joseph McNeel
Keyword(s):  
Liriodendron Tulipifera ◽  
Small Population ◽  
National Standards ◽  
Raw Material ◽  
Low Grade ◽  
Yellow Poplar ◽  
Visual Grade ◽  
Cross Laminated Timber ◽  
Bending Modulus ◽  
Manufacturing Facilities

Abstract Utilization of low-grade yellow-poplar (Liriodendron tulipifera) lumber would provide for alternative structural lumber sources and promote the growth of cross-laminated timber (CLT) manufacturing facilities within the Appalachian Region. A significant amount of low-grade yellow-poplar lumber (i.e., National Hardwood Lumber Association [NHLA] No. 2A and Below Grade) is utilized for wood pallets. In practice, this material is not graded for structural purposes. Additionally, research on yellow-poplar for structural use has focused on grading lumber from a small population of selected logs, not by regrading NHLA lumber from manufacturing facilities. Therefore, the research's objective was to investigate the structural grades of a typical population of NHLA graded No. 2 and lower lumber and evaluate their potential to meet structural grades necessary for CLT panels. NHLA graded lumber was regraded and assigned to visual structural grades following Northeastern Lumber Manufacturers Association rules and evaluated for flatwise bending modulus of elasticity (MOEb) by nondestructive proof loading. The results of the study indicated that 54.6 percent of the boards possessed a minimal structural visual grade required for CLT panels according to American National Standards Institutes/The Engineered Wood Association (ANSI/APA) PRG 320-2019 (2020). Splits were the most common limiting defect that downgraded boards to nonstructural grades. Also, 96.6 percent of the boards evaluated had a MOEb above the required minimal board value of 1.2 ×106 psi (8,274 MPa) listed in ANSI/APA PRG 320-2019 (2020). The results of the study indicated that a majority of NHLA low-grade yellow-poplar, when regraded for structural purposes, meets or exceeds minimum lumber grade values necessary for use in CLT panel production.

Research status of microwave-assisted reduction technology of pyrolusite

2020 ◽  
Vol 07 ◽  
Author(s):  
Li Qiannan ◽  
Ling Yeqing ◽  
Zheng Hewen ◽  
Yang Zhi
Keyword(s):  
Metallurgical Industry ◽  
Raw Material ◽  
Utilization Efficiency ◽  
Low Grade ◽  
Manganese Ore ◽  
Effective Utilization ◽  
Research Status ◽  
Strategic Position ◽  
Research Intensity ◽  
Stable Development

: Manganese ore is an important metallurgical raw material that holds an important strategic position in the national economy of China. However, the grade of manganese ore in the country is mostly low, and the utilization efficiency of lowgrade manganese ore resources is low, which seriously restrict the healthy and stable development of China’s metallurgical industry. As a new green heating method, microwave is expected to address the problems of conventional methods and realize the effective utilization of low-grade manganese ore. In this paper, the research status of the microwave composite reduction of pyrolusite in recent years is reviewed. Microwave plays an important role in metallurgy, and it is the current direction pursued to improve the research intensity of microwave heating and extend it to actual industrial processes.

scholarly journals PULL-OUT RESISTANCE OF SELF-TAPPING SCREWS IN CROSS-LAMINATED TIMBER MADE FROM RADIATA PINE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Xin Li ◽  
Mahmud Ashraf ◽  
Mahbube Subhani ◽  
Paul Kremer
Keyword(s):  
Failure Modes ◽  
Construction Materials ◽  
Structural Response ◽  
Radiata Pine ◽  
Raw Material ◽  
Fibrous Materials ◽  
Cross Laminated Timber ◽  
Pull Out ◽  
Traditional Construction ◽  
Penetration Depths

Cross-laminated timber (CLT) is now considered a viable alternative to traditional construction materials both in mid-rise and high-rise structures. The structural response of CLT heavily relies on the type of timber used in manufacturing, and this can vary significantly based on the original source for this naturally grown raw material. Spruce has been widely used in Europe for CLT production, but in Australia, locally available radiata pine is used by XLam for the manufacturing of their CLT panels. Self-tapping screws (STS) are typically recommended by CLT manufacturers and are most commonly used in relevant construction due to their high load carrying capacities and easy installation process. VGS STSs produced by Rothoblaas were used to investigate their composite actions when pulled-out from three-layer XLam CLT panels with thicknesses of 105 mm and 135 mm. VGS screws with 11 mm in diameter were inserted both parallel-to-grain and perpendicular-to-grain on the narrow face of the CLT panels as part of the current study. Typical failure modes as well as critical penetration depths were carefully recorded. Obtained results showed significant increase of pull-out capacity as penetration depths were increased for considered cases. However, experimental results also showed some obvious inconsistencies. These observations clearly demonstrate the challenges associated with working naturally grown fibrous materials and highlights the importance of major research on this field.

scholarly journals Analysis and Calculation of Stability Coefficients of Cross-Laminated Timber Axial Compression Member

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4267
Author(s):  
Qi Ye ◽  
Yingchun Gong ◽  
Haiqing Ren ◽  
Cheng Guan ◽  
Guofang Wu ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Calculation Method ◽  
National Standards ◽  
Test Results ◽  
Average Deviation ◽  
Stability Coefficient ◽  
Cross Laminated Timber ◽  
Stability Bearing Capacity ◽  
The Stability

Cross-laminated timber (CLT) elements are becoming increasingly popular in multi-storey timber-based structures, which have long been built in many different countries. Various challenges are connected with constructions of this type. One such challenge is that of stabilizing the structure against vertical loads. However, the calculations of the stability bearing capacity of the CLT members in axial compression in the structural design remains unsolved in China. This study aims to determine the stability bearing capacity of the CLT members in axial compression and to propose the calculation method of the stability coefficient. First, the stability coefficient calculation theories in different national standards were analyzed, and then the stability bearing capacity of CLT elements with four slenderness ratios was investigated. Finally, based on the stability coefficient calculation formulae in the GB 50005-2017 standard and the regression method, the calculation method of the stability coefficient for CLT elements was proposed, and the values of the material parameters were determined. The result shows that the average deviation between fitting curve and calculated results of European and American standard is 5.43% and 3.73%, respectively, and the average deviation between the fitting curve and the actual test results was 8.15%. The stability coefficients calculation formulae could be used to predict the stability coefficients of CLT specimens with different slenderness ratios well.

scholarly journals LOW- GRADE STRUCTURES OF NOBLE AND NON- FERROUS METALS AND METHODS OF THEIR SELECTIVE SEPARATION

2021 ◽  
Vol 13 (2) ◽  
pp. 161-169
Author(s):  
Tatyana ALEXANDROVA ◽  
◽  
Anastasia AFANASOVA ◽  
Nadezhda NIKOLAEVA ◽  
◽  
...  
Keyword(s):  
Development Strategy ◽  
Raw Materials ◽  
Close Association ◽  
Mining Industry ◽  
Raw Material ◽  
Free Form ◽  
Mineral Matter ◽  
Low Grade ◽  
Rare Metals ◽  
Flotation Process

There is a worldwide trend of increasing the share of extraction and processing of low-grade minerals, but their extraction and processing volumes are still low. There are several reasons for this: high mining and transportation costs, imperfect techniques and technological difficulties in enrichment and processing of refractory and low-quality minerals. Due to the depletion of reserves of easily beneficiated raw materials and to compensate for the growing shortage of high-quality minerals, the Russian mining industry development strategy provides for the involvement of new and unconventional types of deposits into production. Examples of such deposits are deposits of carbonaceous raw materials (black shale, refractory sulphide carbon-bearing ores, impactites, etc.) containing carbon of varying degrees of metamorphism. On the basis of the most modern mineralogical, physical, nuclear and chemical methods of research of composition, structure and properties of the carbonaceous raw materials at the micro- and nanolevel, the composition of the productive mineral matter, physical, chemical and thermodynamic laws of separation of valuable mineral components and the basic technological processes to obtain the finished product for valorization of the unconventional carbonaceous mineral raw materials were determined with maximum reliability. One of the possible reasons of difficulty of beneficiation of carbonaceous raw materials is the fine phenocrysts in graphite which can be solved by using the flotation process. Contrast of surface properties of minerals with similar technological properties can be increased by application of different energy effects (MEMI, MIO, microwave, electrochemical treatment etc.) at successive stages of raw material transformation, regulation of pulp conditioning conditions (duration and intensity of agitation, heat treatment of pulp) as well as by development and application of selective reagent regimes. The special feature of flotation as a method of extraction of noble and rare metals is the ability to extract valuable metals not only in their native free form, but also in close association with sulphides and carbon. Flotation with the use of intensifying influences made it possible to transfereven low-sized structures of noble and rare metals, which are not extracted by conventional methods of cyanidation, gravitation enrichment and amalgamation, into the concentrate. One of the ways to increase the efficiency of the flotation process is preliminary modification of the additive which is introduced in addition to the main reagents of the sinter - “carrier material”.

American tulipwood (Liriodendron tulipifera L.) as an innovative material in CLT technology

2021 ◽  
Vol 115 ◽  
pp. 18-28
Author(s):  
Teresa Kłosińska
Keyword(s):  
Robinia Pseudoacacia ◽  
Abies Alba ◽  
Liriodendron Tulipifera ◽  
Wood Products ◽  
Raw Material ◽  
Adjacent Layer ◽  
White Fir ◽  
Innovative Material ◽  
Production Technologies ◽  
Robinia Pseudoacacia L

American tulipwood (Liriodendron tulipifera L.) as an innovative material in CLT technology. CLT (cross laminated timber, X-Lam) is one type of engineered wood products. The first idea of CLT was presented in the seventies of the last century. It is manufactured with timber boards placed side by side commonly with 3, 5 and 7 layers glued at 90 degrees to adjacent layer. The CLT production technology was developed for softwood. The main species in CLT production is Norway spruce (Picea abies L.) and less often White fir (Abies alba Mill.). Hardwood is also used more and more for production of CLT, most often, the wood of Silver birch (Betula pendula Roth.), Ash (Fraxinus excelsior L.), poplars (Populus spp.), Locust tree (Robinia pseudoacacia L.). This paper describes the suitability of cheap tulipwood (Liriodendron tulipifera L.) as a raw material for the production of CLT. Examples of the use of this type of panels in construction are also presented. The tulipwood has similar physical characteristics to softwood, for which CLT production technologies were previously developed. This makes it possible to use the technology previously for softwood CLT was developed. In addition, the tulipwood is characterized by aesthetic visual quality (wood surface similar to marble). Thanks to this, CLT boards to make exposed surfaces can be used.

Synthesis of NPK fertilizer from low-grade phosphate raw material

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Anar Kareeva ◽  
Uilesbek Besterekov ◽  
Perizat Abdurazova ◽  
Ulzhalgas Nazarbek ◽  
Irina Pochitalkina ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphical Method ◽  
Raw Materials ◽  
Xrd Analysis ◽  
Raw Material ◽  
Low Grade ◽  
Phosphate Raw Material ◽  
Npk Fertilizer ◽  
Scanning Electron ◽  
Comprehensive Study

Abstract The article presents the results of studies of the process of obtaining NPK fertilizer from low-grade phosphate raw materials with P2O5 of about 18%. Phosphate raw materials were leached with a mixture of nitric-phosphoric acids with the addition of potassium carbonate, which serves as a source of potassium in the final product. The main parameters determined were the content of the main nutrients P2O5:N:K2O, temperature and time of the leaching process. According to the graphical method, the “apparent” activation energy of the heterogeneous process is found, which is equal to 3.8 kJ/mol indicates the intradiffusion nature of the process. Methods of chemical analysis, scanning electron microscopy and XRD analysis were used for a comprehensive study of raw materials and final products.

scholarly journals Life Cycle Assessment (LCA) of Cross-Laminated Timber (CLT) Produced in Western Washington: The Role of Logistics and Wood Species Mix

2019 ◽  
Vol 11 (5) ◽  
pp. 1278 ◽  
Author(s):  
Cindy Chen ◽  
Francesca Pierobon ◽  
Indroneil Ganguly
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impacts ◽  
Wood Species ◽  
Picea Sitchensis ◽  
Wood Products ◽  
Cross Laminated Timber ◽  
Environmentally Sustainable ◽  
Western Washington ◽  
Manufacturing Facilities

The use of cross-laminated timber (CLT), as an environmentally sustainable building material, has generated significant interest among the wood products industry, architects and policy makers in Washington State. However, the environmental impacts of CLT panels can vary significantly depending on material logistics and wood species mix. This study developed a regionally specific cradle-to-gate life cycle assessment of CLT produced in western Washington. Specifically, this study focused on transportation logistics, mill location, and relevant wood species mixes to provide a comparative analysis for CLT produced in the region. For this study, five sawmills (potential lamstock suppliers) in western Washington were selected along with two hypothetical CLT mills. The results show that the location of lumber suppliers, in reference to the CLT manufacturing facilities, and the wood species mix are important factors in determining the total environmental impacts of the CLT production. Additionally, changing wood species used for lumber from a heavier species such as Douglas-fir (Pseudotsuga menziesii) to a lighter species such as Sitka spruce (Picea sitchensis) could generate significant reduction in the global warming potential (GWP) of CLT. Given the size and location of the CLT manufacturing facilities, the mills can achieve up to 14% reduction in the overall GWP of the CLT panels by sourcing the lumber locally and using lighter wood species.

Effect of Control Technology on Properties of Quartz Porous Brick

2018 ◽  
Vol 777 ◽  
pp. 564-568 ◽  
Author(s):  
Long He ◽  
Jin Shi Li ◽  
Mei Hua Chen ◽  
Yan Yang ◽  
Xin Peng Lou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Quartz Sand ◽  
High Performance ◽  
Performance Test ◽  
Holding Time ◽  
Raw Material ◽  
Process Conditions ◽  
Low Grade ◽  
Sintering Process ◽  
Foaming Agent

A high-performance quartz sand insulation brick was prepared by using low grade quartz sand under different sintering process conditions. The optimum sintering process conditions were obtained by analyzing the relationship between microstructure and sintering process. Through the compounding, pulping, forming, drying and sintering processes, and the performance test of the porous brick, the following conclusions can be drawn, the comprehensive performance in all aspects, the porosity is similar, the preferred high compressive strength conditions, in order to get a best The bonding point, brick body sintering temperature of 1150 °C, porosity of 74.56%, compressive strength of 2.1 MPa of porous brick, and the pores are smooth, more uniform distribution. With the prolonging of the holding time, the porosity of the porous brick is reduced, and the performance is 1h, the porosity is 77.22% and the compressive strength is 2.05 MPa. When the raw material ratio is 60% quartz sand, 30wt% kaolin, calcium carbonate 9.6wt%, foaming agent 0.4wt%, water ratio 0.9 holding time at 1h sintering at 1150°C can get better porosity and compressive strength of the insulation brick. The porous material was sintered at 1150 °C, the content of foaming agent was 0.2wt%, the ratio of water to material was 0.9, and the compressive pressure and porosity were the better.

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