scholarly journals Physical and Mechanical Properties of Kenaf (Hibiscus cannabinus L.) Stems at Varying Moisture Contents

Author(s):  
S. A. Fagbemi

The physical and mechanical properties of Nigerian variety Kenaf stems Ibadan Local were studied. Plant height was ranged from 224 cm to 327 cm and maximum stem diameter was ranged from 15 mm to 50 mm. The mechanical properties revealed that maximum cutting force and shearing energy were 1778.62 N and 10.20 J, respectively for 37% moisture content while it was 742.67 N and 3.74 J for 77% moisture content. The Young’s modulus ranged from 60.04 – 266.80 MPa. The greater shearing energy was obtained at the base of the stem.

2014 ◽  
Vol 931-932 ◽  
pp. 1574-1581
Author(s):  
Nirattisak Khongthon ◽  
Somposh Sudajan

The physical and mechanical properties of sugarcane leaves were necessary for the design consideration of the relating storage, handling and processing equipment. The sugarcane trash at moisture contents of 23.40 and 73.91 % w.b. were used for this study. The mean length and unit weight of sugarcane trashes were 168.63 cm and 65.87 grams respectively. The average number of leaf of each sample was 4. The mean diameter of the thrash top, width and thickness increased with the increase of moisture from 23.40 and 73.91 % w.b.. The average leaf angles (β) relative to the horizontal plane of the first left leaf, second left leaf, first right leaf and second right leaf were 65.10, 73.36, 71.07 and 78.26 degrees for 73.91 % w.b., and 66.33, 73.50, 67.50 and 75.83 degrees for 23.40 % w.b. respectively. When the moisture content increased from 23.40 to 73.91% w.b., the static coefficient of friction increased from 0.30 to 0.43, 0.38 to 0.41, 0.30 to 0.37 and 0.54 to 0.66 for plywood, mild steel, galvanized iron and rubber plate respectively. The least static coefficient of friction occurred on the galvanized iron plate. The results from experimenting on mechanical properties showed that the maximum shearing force increased with the increase in moisture content from 23.40 to 73.91% w.b. respectively. The maximum shearing force was 360.15 and 457.32 N for moisture contents of 23.40 and 73.91% w.b.. The maximum tensile force decreased toward upper region of the leaf for both 23.40 and 73.91% w.b.. The results of this study would be useful for the design and optimization of the equipment associated with harvesting, threshing, chopping and processing.


Author(s):  
Khaled Abdeen Mousa Ali ◽  
Wang Yuan Zong ◽  
Lin Yang ◽  
Horia Mohamed Abd El-Ghany

This study was carried out to measure some physical and mechanical properties of the sunflower seeds variety “DW667”. The physical properties (length, width, thickness, equivalent diameter, sphericity, surface area of seed, one thousand seed mass, bulk and true density, porosity) and mechanical properties (compressive load and displacement deformation for vertical and horizontal orientations) were measured at 4%, 10%, 15%, 20% and 25% Dray basis (d.b.) moisture contents. Higher moisture content from 4%to25% increased length, width, thickness, equivalent diameter, sphericity, surface area of seed, one thousand seed mass, bulk and true density, porosity and deformation displacement at the vertical and horizontal orientations of seeds increased from 10.57 to , 4.50 to , 2.85 to , 5.13 to , 49 to 50 %, 82.95 to 94.53 mm2, 33.70 to , 286.80 to 314.98 kg/m3, 406.47 to 483.61 kg/m3, 29.22 to 34.54 %, 1.63 to 2.63 mm and 0.70 to 1.87 mm, respectively. While the required compressive force for rupture seeds decreased from 25.3 to 12.39 N and 11.5 to 5.63 N for vertical and horizontal orientations, respectively with moisture contents uprising from 4 to 25 %. The findings of this study will open new windows in farm mechanization for the designing and improvement of treatment machines for this type of seed.


2017 ◽  
Vol 63 (No. 1) ◽  
pp. 23-28 ◽  
Author(s):  
Kaewwinud Nisanath ◽  
Khokhajaikiat Porntep ◽  
Boonma Apichart

In an attempt to investigate the potential of using cassava stalk as a biomass material and determine the design requirements for developing a cutting machine, this study aims to investigate physical and mechanical properties of cassavas stalk, under the influence of moisture content and region of cut using statistical techniques. Moisture contents were ranged into three different levels; 54.19, 43.05 and 24.93% wet basis (w.b.) while cutting regions were classified as top (tip of cassava stalk), middle and bottom. Mechanical properties were represented by shearing stress. Physical properties, on the other hand, were represented by length, diameter, and mass. By decreasing moisture levels, all parameter values were reduced, except shearing stress. Moreover, it was found that shearing stress increased when lowering the cutting line. Maximum and minimum shearing stress occurred at bottom and top regions of the stalk, respectively. Most importantly, moisture content and region of cut both had a significant influence (P < 0.05) on shearing stress, although the latter had much larger impact.


Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 717
Author(s):  
Dang Duc Viet ◽  
Te Ma ◽  
Tetsuya Inagaki ◽  
Nguyen Tu Kim ◽  
Nghiem Quynh Chi ◽  
...  

Acacia plants are globally important resources in the wood industry, but particularly in Southeast Asian countries. In the present study, we compared the physical and mechanical properties of polyploid Acacia (3x and 4x) clones with those of diploid (2x) clones grown in Vietnam. We randomly selected 29 trees aged 3.8 years from different taxa for investigation. BV10 and BV16 clones represented the diploid controls; X101 and X102 were the triploid clones; and AA-4x, AM-4x, and AH-4x represented neo-tetraploid families of Acacia auriculiformis, Acacia mangium, and their hybrid clones. The following metrics were measured in each plant: stem height levels, basic density, air-dry equilibrium moisture content, modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and Young’s modulus. We found that the equilibrium moisture content significantly differed among clones, and basic density varied from pith-to-bark and in an axial direction. In addition, the basic density of AA-4x was significantly higher than that of the control clones. Furthermore, the MOR of AM-4x was considerably lower than the control clones, whereas the MOE of X101 was significantly higher than the control values. The compression strength of AM-4x was significantly lower than that of the control clones, but AH-4x had a significantly higher Young’s modulus. Our results suggest that polyploid Acacia hybrids have the potential to be alternative species for providing wood with improved properties to the forestry sector of Vietnam. Furthermore, the significant differences among the clones indicate that opportunities exist for selection and the improvement of wood quality via selective breeding for specific properties.


2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.


2019 ◽  
Vol 11 (4) ◽  
pp. 279
Author(s):  
Gabrielly B. Rodrigues ◽  
Osvaldo Resende ◽  
Daniel E. C. de Oliveira ◽  
Lígia C. de M. Silva ◽  
Weder N. Ferreira Junior

This study aimed to evaluate the influence of drying at different temperatures on the mechanical properties of grains of grain sorghum subjected to compression at the natural rest position. Grains dried at temperatures of 60, 80 and 100 °C with different moisture contents (0.515; 0.408; 0.315; 0.234; 0.162 and 0.099 (d.b.)) were subjected to uniaxial compression between two parallel plates, applied at their natural rest position, at a rate of 0.001 m s-1. The force required to rupture in grains of grain sorghum increased as their moisture contents decreased, with values of 47.17 to 78.44 N, 61.81 to 69.66 N and 52.07 to 70.89 N for the temperatures of 60, 80 and 100 °C, respectively. The compression force required to deform grain sorghum decreased with the increment in moisture content, and the proportional deformation modulus increases with moisture content reduction. Within the studied range of moisture content, the values were 87 × 10-7 to 354.99 × 10-7 Pa, 132.63 × 10-7 to 465.98 × 10-7 Pa and 80.18 × 10-7 to 429.85 × 10-7 Pa for the temperatures of 60, 80 and 100 °C, respectively.


2020 ◽  
Author(s):  
Jackie E. Kendrick ◽  
Lauren N. Schaefer ◽  
Jenny Schauroth ◽  
Andrew F. Bell ◽  
Oliver D. Lamb ◽  
...  

Abstract. Volcanoes represent one of the most critical geological settings for hazard modelling due to their propensity to both unpredictably erupt and collapse, even in times of quiescence. Volcanoes are heterogeneous at multiple scales, from porosity which is variably distributed and frequently anisotropic to strata that are laterally discontinuous and commonly pierced by fractures and faults. Due to variable and, at times, intense stress and strain conditions during and post-emplacement, volcanic rocks span an exceptionally wide range of physical and mechanical properties. Understanding the constituent materials' attributes is key to improving the interpretation of hazards posed by the diverse array of volcanic complexes. Here, we examine the spectrum of physical and mechanical properties presented by a single dome-forming eruption at a dacitic volcano, Mount Unzen (Japan) by testing a number of isotropic and anisotropic lavas in tension and compression and using monitored acoustic emission (AE) analysis. The lava dome was erupted as a series of 13 lobes between 1991–1995, and its ongoing instability means much of the volcano and its surroundings remain within an exclusion zone today. During a field campaign in 2015, we selected 4 representative blocks as the focus of this study. The core samples from each block span range in porosity from 9.14 to 42.81 %, and permeability ranges from 1.54 × 10−14 to 2.67 × 10−10 m2 (from 1065 measurements). For a given porosity, sample permeability varies by > 2 orders of magnitude is lower for macroscopically anisotropic samples than isotropic samples of similar porosity. An additional 379 permeability measurements on planar block surfaces ranged from 1.90 × 10−15 to 2.58 × 10−12 m2, with a single block having higher standard deviation and coefficient of variation than a single core. Permeability under confined conditions showed that the lowest permeability samples, whose porosity largely comprises microfractures, are most sensitive to effective pressure. The permeability measurements highlight the importance of both scale and confinement conditions in the description of permeability. The uniaxial compressive strength (UCS) ranges from 13.48 to 47.80 MPa, and tensile strength (UTS) using the Brazilian disc method ranges from 1.30 to 3.70 MPa, with crack-dominated lavas being weaker than vesicle-dominated materials of equivalent porosity. UCS is lower in saturated conditions, whilst the impact of saturation on UTS is variable. UCS is between 6.8 and 17.3 times higher than UTS, with anisotropic samples forming each end member. The Young's modulus of dry samples ranges from 4.49 to 21.59 GPa and is systematically reduced in water-saturated tests. The interrelation of porosity, UCS, UTS and Young's modulus was modelled with good replication of the data. Acceleration of monitored acoustic emission (AE) rates during deformation was assessed by fitting Poisson point process models in a Bayesian framework. An exponential acceleration model closely replicated the tensile strength tests, whilst compressive tests tended to have relatively high early rates of AEs, suggesting failure forecast may be more accurate in tensile regimes, though with shorter warning times. The Gutenberg-Richter b-value has a negative correlation with connected porosity for both UCS and UTS tests which we attribute to different stress intensities caused by differing pore networks. b-value is higher for UTS than UCS, and typically decreases (positive Δb) during tests, with the exception of cataclastic samples in compression. Δb correlates positively with connected porosity in compression, and negatively in tension. Δb using a fixed sampling length may be a more useful metric for monitoring changes in activity at volcanoes than b-value with an arbitrary starting point. Using coda wave interferometry (CWI) we identify velocity reductions during mechanical testing in compression and tension, the magnitude of which is greater in more porous samples in UTS but independent of porosity in UCS, and which scales to both b-value and Δb. Yet, saturation obscures velocity changes caused by evolving material properties, which could mask damage accrual or source migration in water-rich environments such as volcanoes. The results of this study highlight that heterogeneity and anisotropy within a single system not only add uncertainty but also have a defining role in the channelling of fluid flow and localisation of strain that dictate a volcano's hazards and the geophysical indicators we use to interpret them.


2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Dendi Prayoga ◽  
. Dirhamsyah ◽  
. Nurhaida

This research aimed to examine the physical and mechanical properties of particle boards based on the composition of raw materials and adhesive content and know the treatment of the composition of raw materials and the best adhesive content and meet the standard JIS A 5908-2003. The research was conducted at Wood Workshop Laboratory, Wood Processing Laboratory Faculty of Forestry,Tanjungpura University and Laboratory of PT. Duta Pertiwi Nusantara Pontianak. The adhesive used is Urea Formaldehyde with 52% Solid Content. Comparison of the composition of rice husks and sengon varies namely rice husk 50%: sengon 50%, rice husk 60%: sengon 40% and rice husk 70%: sengon 30%  and variations in the levels of UF adhesives, namely 14% and 16%, with target density 0,7 gr/cm3. The particleboard was 30 cm x 30 cm x 1 cm Pressing at temperature 140oC for 8 minutes, with  pressure of 25 kg/cm2. The research results of the study of density and moisture content meet the standards JIS A 5908-2003. The best particle values of rice husk and sengon  with composition a ratio of  rice husk 50%: sengon 50% , 16% adhesive content  16%, with density value of  0,7072 gr/cm3, moisture content 9,1949 %, thick development 12,3210 %, water absorption 68,8270 %, MOE 12110,7273 kg/cm2, MOR 161,0025 kg/cm2, firmness sticky 1,9320 kg/cm2, screw holding strength 62,3124 kg.Keywords : adhesive, composition, particle board, rice husk, sengon


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
. Erma ◽  
Fadiilah H Usman ◽  
. Muflihati

Physical and mechanical properties of wood is one of the basic properties that need to be known in the selection of wood, because the physical and mechanical properties of wood are not the same height on the stem. Increased wood demand gives the opportunity to use wood that is not yet known for its marketing, one of which is Salam wood (Syzygium polianthum (Wight) Walp). The purpose of this research was to determine the physical and mechanical properties of Salam wood based on the height of the stem so that Salam wood can be optimally utilized by testing based on Classification SNI – 5 PKKI 1961. Methods of making test and test examples based on British Standard Methods No. 373-1957. The results showed that Salam wood has physical properties with an average  brown colour, the moisture content 3,13 % , density  0,58 kg/cm2 , Depreciation 2,59 %. Salam has mechanical properties with an average height position stem from base to tip with Modulus of Elastiscity (MOE)  97.701,54 , Modulus of Rupture (MOR) 659,18  and  Modulus Crushing  Streang 342,86 . Salam can be classified into strong class III and based on its properties and mechanics, it is suitable for use as a lightweight construction and furniture.Keywords: Density, depreciation, MCS, MOE, moisture content, MOR


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