Distribution of lignin in vascular bundles of coconut wood (Cocos nucifera) by cellular UV-spectroscopy and relationship between lignification and tensile strength in single vascular bundles

Holzforschung ◽  
2014 ◽  
Vol 68 (8) ◽  
pp. 915-925 ◽  
Author(s):  
Leila Fathi ◽  
Arno Frühwald ◽  
Gerald Koch

Abstract The topochemical distribution of lignin in vascular bundles separated from different radial positions of Mexican coconut wood stems (Cocos nucifera) has been studied with focus on the relationship between the degree of lignification and tensile strength properties. The cellular lignin distribution was analyzed by UV-microspectrophotometry (UMSP) scanning at 280 nm of sections of vascular bundles (VBs) of 1 μm thickness. The fibers of the VBs with high tensile strength reveal a relatively low UV-absorbance at 280 nm (A280 nm 0.39), whereas the VBs with low tensile strength display the highest A280 nm (0.59). The S2 of fiber walls are characterized by the typical lamellar structure with increasing lignin contents from the cell lumen towards the compound middle lamellae (CML). The A280 nm data of CMLs are higher (0.67 to 0.87) than those of the S2 wall layers. Overall, the A280 nm values of S2 of fibers walls within single VBs of coconut are in the range of 0.36 to 0.59.

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.


2021 ◽  
Vol 4 (1) ◽  
pp. 11
Author(s):  
Khoiriya Latifah ◽  
Joko Siswanto ◽  
Bambang Supriyadi ◽  
Carsoni C

Bamboo is an abundant material and easily available in Indonesia. In addition to having high compressive strength and tensile strength as well as ease of obtaining and low prices, bamboo is a consideration and focus in developing in the world of construction today. In this study, bamboo is used for soil stabilization, where bamboo is used in the form of fibre. This research focuses on the strength properties of various types of bamboo. The focus is to investigate the relationship between the maximum tensile strength of bamboo and the flexibility of bamboo in soil stabilization. This is very important, because bamboo fibers used for soil stabilization rely on their tensile strength rather than their compressive strength. Thus, the optimum tensile strength and flexibility of bamboo must be of particular concern. From the results of the study of the tensile strength of two types of bamboo, namely Apus Bamboo and Java Bamboo, the Apus Bamboo results were found to have a higher tensile strength of 225.57 mpa with maximum flexibility of 19.99 mm and 43.76 mpa for tensile strength of Javanese Bamboo with a level of flexibility of 10.26 mm.


Author(s):  
Carla Cavalcante Araújo ◽  
Gibson Rocha Meira

abstract: Periodic inspections in reinforced concrete structures are important to be carried out to assess their state of conservation. In this scenario, non-destructive tests can be a suitable option since destructive tests are invasive and may be difficult to be performed in some cases. Considering this option, correlations between non-destructive test parameters and the concrete properties to be analyzed are useful tools that make easier the structure inspection. In the present work, correlations between the compressive strength (fc) and splitting tensile strength (ft) and surface electrical resistivity (ρ) of concretes were studied. Brazilian concretes of six different mixtures were analyzed at five different ages and correlation curves between strength properties and surface electrical resistivity of concrete were obtained, which are represented by the general relationships fc= 14.18·ln(ρ) + 18.43 and ft = 0.69·ln(ρ) + 2.15 for compressive strength and splitting tensile strength, respectively. In addition, a general curve considering literature data and results from this work was proposed to represent the relationship between compressive strength and surface electrical resistivity - fc = 11.89·ln(ρ) + 18.90.


TAPPI Journal ◽  
2016 ◽  
Vol 15 (11) ◽  
pp. 731-738 ◽  
Author(s):  
KARITA KINNUNEN-RAUDASKOSKI ◽  
KRISTIAN SALMINEN ◽  
JANI LEHMONEN ◽  
TUOMO HJELT

Production cost savings by lowering basis weight has been a trend in papermaking. The strategy has been to decrease the amount of softwood kraft pulp and increase use of fillers and recycled fibers. These changes have a tendency to lower strength properties of both the wet and dry web. To compensate for the strength loss in the paper, a greater quantity of strength additives is often required, either dosed at the wet end or applied to the wet web by spray. In this pilot-scale study, it was shown how strength additives can be effectively applied with foam-based application technology. The technology can simultaneously increase dryness after wet pressing and enhance dry and wet web strength properties. Foam application of polyvinyl alcohol (PVA), ethylene vinyl alcohol (EVOH), carboxymethyl cellulose (CMC), guar gum, starch, and cellulose microfibrils (CMF) increased web dryness after wet pressing up to 5.2%-units compared to the reference sample. The enhanced dewatering with starch, guar gum, and CMF was detected with a bulk increase. Additionally, a significant increase in z-directional tensile strength of dry web and and in-plane tensile strength properties of wet web was obtained. Based on the results, foam application technology can be a very useful technology for several applications in the paper industry.


Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  

Abstract Lucefin Group C30, C30E, and C30R are medium-carbon, non-alloy steels that are used in the normalized, cold worked, or quenched and tempered condition. C30E and C30R may also be flame or induction hardened. C30, C30E, and C30R are widely used for small, moderately stressed parts, where higher strength levels are needed than can be achieved in the lower carbon grades, and also where toughness is more important than high tensile strength. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: CS-206. Producer or source: Lucefin S.p.A.


Alloy Digest ◽  
1997 ◽  
Vol 46 (10) ◽  

Abstract Vasco 9-4-20 (0.20 wt% C) is a premium quality aircraft steel that combines high tensile strength with good fracture toughness. It is a heat-treatable alloy capable of developing an ultimate tensile strength greater than 190 ksi. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SA-489. Producer or source: Vasco, An Allegheny Teledyne Company.


Alloy Digest ◽  
1976 ◽  
Vol 25 (12) ◽  

Abstract NJZ Alloy No. 55 is a zinc-cadmium alloy characterized by high tensile strength and hardness but low ductility. It has high stiffness and resiliency but low drawing and forming characteristics. Its applications include hardware and medallions. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep and fatigue. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: Zn-30. Producer or source: New Jersey Zinc Company.


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