Efficiency of Machine Sanding of Wood

We hypothesized that the type of wood, in combination with the grit size of sandpapers, would affect sanding efficiency. Fixed factors were used in the experiment (a belt sander with pressure p = 3828 Pa, and a belt speed of vs = 14.5 m/s) as well as variable factors (three sand belts (P60, P120, P180), six hardwood species (beech, oak, ash, hornbeam, alder, walnut) and three softwood species (pine, spruce, larch)). The masses of the test samples were measured until they were completely sanded. The sanding efficiency of hardwood species is less variable than for softwood species. Maximum sanding efficiency for the softwood ranged from 1 to 2 min, while for the hardwood species, it ranged from 2 to 4.5 min at the start of sanding and then decreased. The average time for complete sanding of the softwood samples was: 87 s (P60), 150 s (P120), and 188 s (P180). For hardwood, these times were 2.4, 1.5, and 1.8 times longer. The results indicate that the factors determining sanding efficiency are the type of wood, and, secondly, the grit size of sanding belts. In the first phase of blunting with the sanding belts, the sanding processes of hardwood and softwood are significantly different. In the second phase of blunting, sanding belts with higher grit numbers (P120 and P180) behaved similarly while sanding hardwood and softwood.

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EFFECTS OF BELT SPEED, PRESSURE AND GRIT SIZE ON THE SANDING OF Pinus elliottii WOOD

CERNE ◽

10.1590/01047760201521011216 ◽

2015 ◽

Vol 21 (1) ◽

pp. 45-50 ◽

Cited By ~ 3

Author(s):

Manoel Cléber de Sampaio Alves ◽

Luiz Fernando Frezzatti Santiago ◽

Marcos Tadeu Tiburcio Gonçalves ◽

Ivaldo De Domênico Valarelli ◽

Francisco Mateus Faria de Almeida Varasquim

Keyword(s):

Surface Roughness ◽

Analysis Of Variance ◽

Block Design ◽

Pinus Elliottii ◽

Grit Size ◽

Significance Level ◽

Belt Speed ◽

Randomized Complete Block Design ◽

Four Levels ◽

Temperature Levels

The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size) on the output parameters (temperature and surface roughness) for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD). The results were analyzed employing the analysis of variance (ANOVA) with 5% of significance level. Only grit sizes were significant to different temperature levels. The same outcome was observed for roughness, where only grits sizes were significant. No interaction between the pressure and belt speed factors were observed for all the results analyzed.

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Resistance and Collaboration in the Philippine-American War: The Case of Batangas

Journal of Southeast Asian Studies ◽

10.1017/s0022463400012212 ◽

1984 ◽

Vol 15 (1) ◽

pp. 69-90 ◽

Cited By ~ 1

Author(s):

Glenn A. May

Keyword(s):

Middle Class ◽

Second Phase ◽

College Level ◽

Standard Account ◽

War Effort ◽

The Republic ◽

The Masses

For more than two decades, the standard account of the Filipino side of the Philippine-American War has been Teodoro Agoncillo's Malolos: The Crisis of the Republic. Agoncillo's book is, by the author's own admission, a celebration of the role of the Filipino “masses” in the second phase of the Philippine Revolution. “If I appear inclined to sympathize with the masses”, he writes, “it is because their faith in the cause of the Republic was unshaken and their patriotism and self-sacrifice unsullied by selfish motives.” The villains of his story are the “Haves” (Agoncillo also refers to them as the “plutocrats” and the “middle class”) who, in his view, betrayed their countrymen by collaborating with the Americans and undermining the war effort. He directs his harshest criticism at Trinidad H. Pardo de Tavera, Benito Legarda, Cayetano Arellano, and other Manila-based men of means. Agoncillo repeats this story, albeit in briefer form, in a popular college-level text, which he coauthored with Milagros Guerrero.

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Influence of Grit Size and Wood Species on the Granularity of Dust Particles during Sanding

Applied Sciences ◽

10.3390/app10228165 ◽

2020 ◽

Vol 10 (22) ◽

pp. 8165

Author(s):

Marta Pędzik ◽

Kinga Stuper-Szablewska ◽

Maciej Sydor ◽

Tomasz Rogoziński

Keyword(s):

Particle Size ◽

Grit Size ◽

Dust Particles ◽

Wood Dust ◽

Particle Sizes ◽

Respirable Fraction ◽

Dust Fraction ◽

The Mean ◽

Oak Ash

Wood dust poses a threat to the health of employees and the risk of explosion and fire, accelerates the wear of machines, worsens the quality of processing, and requires large financial outlays for its removal. The aim of this study was to investigate the extent to which the grit size of sandpaper influences the size of the wood dust particles and the proportion of the finest particles which, when dispersed in the air, may constitute the respirable fraction. Six species of hardwood (beech, oak, ash, hornbeam, alder, and walnut), and three species of softwood (larch, pine, and spruce) were used in the research. While sanding the samples under the established laboratory conditions, the following were measured for two types of sandpapers (grit sizes P60 and P180): mean arithmetic particle size of dust and finest dust particles content (<10 µm). Based on the obtained results, we found that the largest dust particle sizes were obtained for alder, pine, and spruce; the smallest size of dust particles during sanding with both sandpapers was obtained for beech, hornbeam, oak, ash, larch, and walnut. The mean arithmetic particle sizes ranged from 327.98 µm for pine to 104.23 µm for hornbeam. The mean particle size of the dust obtained with P60 granulation paper was 1.4 times larger than that of the dust obtained with P180 granulation sandpaper. The content of the finest dust particles ranged from 0.21% for pine (P60 sandpaper) to 12.58% for beech (P180 sandpaper).The type of wood (hardwood or softwood) has a significant influence on the particle size and the content of the finest dust fraction.

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Erythro/threo ratio of β-O-4-5 structures as an important structural characteristic of lignin. Part 4: Variation in the erythro/threo ratio in softwood and hardwood lignins and its relation to syringyl/guaiacyl ratio

Holzforschung ◽

10.1515/hf.2005.045 ◽

2005 ◽

Vol 59 (3) ◽

pp. 276-281 ◽

Cited By ~ 60

Author(s):

Takuya Akiyama ◽

Hitoshi Goto ◽

Deded S. Nawawi ◽

Wasrin Syafii ◽

Yuji Matsumoto ◽

...

Keyword(s):

Correlation Coefficient ◽

Structural Characteristic ◽

Wood Species ◽

Vanillic Acid ◽

Syringic Acid ◽

Molar Ratio ◽

Strongly Correlated ◽

Hardwood Species ◽

The Relationship ◽

Softwood Species

Abstract The proportion of erythro- and threo-forms of β-O-4-structures in lignin was elucidated by ozonation analysis of 21 wood species, and the relationship to the syringyl and guaiacyl composition was investigated. For all hardwood species, the erythro-form of β-O-4-structures predominated, although the extent varied widely, depending on wood species. In contrast, the proportion and amount of erythro- and threo-forms were very similar in all softwood species. The proportion of the erythro-form was greater in species with a higher methoxyl content in the lignin (correlation coefficient, R2=0.83). The S/V ratio (molar ratio of syringaldehyde and syringic acid to that of vanillin and vanillic acid) obtained by nitrobenzene oxidation was also strongly correlated with the proportion of the erythro-form (R2=0.99). Accordingly, the syringyl/guaiacyl ratio is closely related to the erythro/threo ratio. This stereochemical characteristic of β-O-4-structures is discussed in relation to the process of lignin formation.

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Comparative Studies on Two Types of OSB Boards Obtained from Mixed Resinous and Fast-growing Hard Wood

Applied Sciences ◽

10.3390/app10196634 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6634

Author(s):

Aurel Lunguleasa ◽

Adela-Eliza Dumitrascu ◽

Valentina-Doina Ciobanu

Keyword(s):

Modulus Of Elasticity ◽

Internal Bond ◽

Elasticity Modulus ◽

Modulus Of Rupture ◽

Deciduous Trees ◽

Fast Growing ◽

Hardwood Species ◽

Industry Standards ◽

Softwood Species ◽

Made In

The paper aims to compare the oriented strand boards (OSBs) made in the laboratory from a mixture of softwood species to those made from hardwood species, followed by their comparison to European and industry standards. In this regard, the main properties of the panels made in the laboratory were determined, including density, absorption, and swelling in thickness, modulus of elasticity, modulus of rupture, and internal bond. The analysis of the properties of swelling (24 h) and absorption (24 h) revealed that the mixture of softwood species was slightly better thanthe hardwood one. It was also shown that the panels manufactured from the mixture of hardwood species had better mechanical properties than those made of the softwood mixture (modulus of rupture (MOR) = 43.48 N/mm2, modulus of elasticity (MOE) = 7253 N/mm, and internal bond (IB) = 1.57 N/mm2). Additionally, the comparative analysis of properties indicates that the density is highly significant in determining the MOE values of the OSBs. This will allow softwood speciestobe replaced with other species of soft and fast-growing deciduous trees such as willow, birch, and poplar in the manufacture of oriented strand boards.

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The Political Leadership of Mao Zedong

Journal of Contemporary Educational Research ◽

10.26689/jcer.v2i4.407 ◽

2018 ◽

Vol 2 (4) ◽

pp. 28-33

Author(s):

Donia Zhang

Keyword(s):

Cultural Revolution ◽

Chinese Communist Party ◽

Mao Zedong ◽

Party Leader ◽

The Political ◽

Second Phase ◽

Political Movements ◽

Great Leap Forward ◽

The Great Leap Forward ◽

The Masses

This paper presents an analysis of the former Chinese Communist Party leader Chairman Mao Zedong's political career (reigned 1949-1976), with regards to his success and failures. Mao was one of the most prominent Communist theoreticians who governed a quarter of humankind for a quarter of a century. His political philosophy, particularly his Method of Leadership, focusing on the "masses" is discussed here. The analytical arguments are centered on three phases of his leadership: the rise, the apex, and the fall. In the first phase, the paper attributes his victory before 1949 to his profound understanding of Chinese peasants. In the second phase, it elaborates on his successful method of leadership in the early 1950s. And in the third and last phase, it criticizes his disastrous political movements, particularly the Great Leap Forward and the Cultural Revolution, from the late 1950s to the mid-1970s. The study hopes to offer an objective and a balanced view of Chairman Mao, who had a complex personality and was a highly controversial figure in human history. The article also wishes to help readers gain a better understanding of China's top leader in recent history, and how China came to be what it is today.

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Contact And Non-Contact Proportions Between Axial Elements and Rays

IAWA Journal ◽

10.1163/22941932-90001594 ◽

2003 ◽

Vol 24 (3) ◽

pp. 247-255 ◽

Cited By ~ 4

Author(s):

Chunhua Zhang ◽

Minoru Fujita ◽

Keiji Takabe

Keyword(s):

Cryptomeria Japonica ◽

Chamaecyparis Obtusa ◽

Pinus Thunbergii ◽

Wood Fibers ◽

Paulownia Tomentosa ◽

Axial Parenchyma ◽

Albizia Julibrissin ◽

Contact Rates ◽

Hardwood Species ◽

Softwood Species

Proportions ofaxial elements without any spatial contacts with rays were investigated. Non-contact rates between rays and fusiforrn initials or axial parenchyma strands were examined in tangential sections of cambial or axial parenchyma zones in 21 hardwood species . The noncontact rates were very different among species, ranging from 0% to 76%. Serial trans verse sections of xylem were used to deterrnine the non-contact rates between rays and wood fibers in 3 of the 21 hardwood species having high non-contact rates of parenchyma strands . The noncontact rate of wood fibers was 49% in Albizia julibrissin (non-storied cambium), 30% in Paulownia tomentosa (non-storied cambium), and 52% in Pterocymbium beccarii (storied cambium). Tangential seetions of three softwood species, Pinus thunbergii, Cryptomeria japonica, and Chamaecyparis obtusa were used to investigate the contacts between rays and tracheids. All tracheids in the three species had contact with at least one ray, ranging from 1 to 15 rays.

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Digestibility of sawdust estimated by the nylon bag technique

Australian Journal of Experimental Agriculture ◽

10.1071/ea9810052 ◽

1981 ◽

Vol 21 (108) ◽

pp. 52 ◽

Cited By ~ 3

Author(s):

RA Hunter ◽

DB Purser ◽

RJW Barron

Keyword(s):

Pinus Pinaster ◽

Dry Matter ◽

Lignin Concentration ◽

Hardwood Species ◽

Hoop Pine ◽

Araucaria Cunninghamii ◽

Ruminal Digestion ◽

Eucalyptus Maculata ◽

Softwood Species

The digestibilities of sawdust from one hardwood species, Spotted Gum (Eucalyptus maculata), and two softwood species, Hoop Pine (Araucaria cunninghamii) and Pinus pinaster, were estimated by the nylon bag technique. The dry matter digestibilities were 8.3, 1.7 and 4.4%, respectively. Lignin concentration was possibly a major factor affecting digestibility as the values were 16.4,32.3 and 27.8%, respectively. For each species the ruminal digestion was completed within 48 h.

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Influence of belt speed, grit sizes and pressure on the sanding of Eucalyptus grandis wood

CERNE ◽

10.1590/s0104-77602012000200007 ◽

2012 ◽

Vol 18 (2) ◽

pp. 231-237 ◽

Cited By ~ 7

Author(s):

Francisco Mateus Faria de Almeida Varasquim ◽

Manoel Cléber de Sampaio Alves ◽

Marcos Tadeu Tiburcio Gonçalves ◽

Luis Fernando Frezzatti Santiago ◽

Alexandre Jorge Duarte de Souza

Keyword(s):

Surface Roughness ◽

Power Consumption ◽

Cutting Force ◽

Eucalyptus Grandis ◽

Cutting Speed ◽

Wood Products ◽

Grit Size ◽

Belt Speed ◽

Surface Finishes ◽

Input Parameters

The sanding process is important to the quality of wood products. Sanding reduces imperfections in wood surfaces and it is important to the final product and application of paints or varnishes. There are few studies about sanding in the literature and finding out the relationship between the input parameters (i.e., species of wood, grit size, abrasive) on the output parameters (i.e., roughness, force, pressure) will help to improve this process. This study analyzed the influence of input parameters as belt speed (cutting speed), grit size and pressure on the output parameters as surface roughness, cutting force (sanding force) and power consumption on cross-grain sanding of Eucalyptus grandis wood. The tests were performed with 3 types of grit sizes (80, 100 and 120 grit), 3 belt speeds (10, 11 and 12 m/s) and 2 pressures (219.89 and 283.44 g/cm²). The surface roughness was analyzed based on roughness average (Ra). Sanding efforts were analyzed by cutting force and power consumption. It was found that the 100 grit size provided the lowest cutting force. It was observed that the belt speed, pressure and grit size influenced the surface roughness, cutting force and power consumption. The best surface finishes were obtained in tests with higher pressure.

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A CAS Approach to Handle the Anisotropic Hooke’s Law for Cancellous Bone and Wood

Chinese Journal of Engineering ◽

10.1155/2014/487314 ◽

2014 ◽

Vol 2014 ◽

pp. 1-28

Author(s):

Sandeep Kumar

Keyword(s):

Data Analysis ◽

Elastic Constant ◽

Cancellous Bone ◽

Elastic Constants ◽

Fourth Order ◽

Elasticity Tensor ◽

Eigenvalues And Eigenvectors ◽

Hardwood Species ◽

Maple Code ◽

Softwood Species

The present research entirely relies on the Computer Algebric Systems (CAS) to develop techniques for the data analysis of the sets of elastic constant data measurements. In particular, this study deals with the development of some appropriate programming codes that favor the data analysis of known values of elastic constants for cancellous bone, hardwoods, and softwood species. More precisely, a “Mathematica” code, which has an ability to unfold a fourth-order elasticity tensor is discussed. Also, an effort towards the fabrication of an appropriate “MAPLE” code has been exposed, that can calculate not only the eigenvalues and eigenvectors for cancellous bone, hardwoods, and softwood species, but also computes the nominal average of eigenvectors, average eigenvectors, average eigenvalues, and the average elasticity matrices for these materials. Further, using such a MAPLE code, the histograms corresponding to average elasticity matrices of 15 hardwood species have been plotted and the graphs for I, II, III, IV, V, and VI eigenvalues of each hardwood species against their apparent densities are also drawn.

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