scholarly journals Morphological Analysis of Several Bamboo Species with Potential Structural Applications

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2126
Author(s):  
Asier Elejoste ◽  
Alfonso Arevalillo ◽  
Nagore Gabilondo ◽  
Amaia Butron ◽  
Cristina Peña-Rodriguez

Bamboo constitutes a family of plants that are very promising and interesting as renewable materials for both large and small structure construction. To be used as an alternative to traditional materials; the understanding of its morphology and mechanical behavior is of crucial importance. As the distribution of fibers and vascular bundles differs for each type of bamboo; several bamboo types have been characterized: Phyllostachys aurea (PA), Arundinaria amabilis (AA) and Dendrocalamus strictus (DS). Morphological analysis has been performed by optical (OM) and scanning electron microscopy (SEM). Differences in density; surface morphology and wall thickness have been found. In fact; PA and AA have shown a great morphological regularity; while DS presents the greatest thickness; to the point that it can be considered full culm. The plant’s own ducts constitute a very important factor for future impregnations and the optimization of mechanical properties for structure construction.

Author(s):  
John R. Devaney

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.


Author(s):  
N. Merk ◽  
A. P. Tomsia ◽  
G. Thomas

A recent development of new ceramic materials for structural applications involves the joining of ceramic compounds to metals. Due to the wetting problem, an interlayer material (brazing alloy) is generally used to achieve the bonding. The nature of the interfaces between such dissimilar materials is the subject of intensive studies and is of utmost importance to obtain a controlled microstructure at the discontinuities to satisfy the demanding properties for engineering applications . The brazing alloy is generally ductile and hence, does not readily fracture. It must also wett the ceramic with similar thermal expansion coefficient to avoid large stresses at joints. In the present work we study mullite-molybdenum composites using a brazing alloy for the weldment.A scanning electron micrograph from the cross section of the joining sequence studied here is presented in Fig. 1.


2015 ◽  
Vol 38 (1) ◽  
pp. 87-89
Author(s):  
R. Santhoshkumar ◽  
K.V. Bhat

Bamboo species is widely used for different purposes in the different parts of World. The variation in properties of the culms of bamboos are affected its use. Shrinkage is one of the physical properties in bamboo and it will affect the products. In this article deals with the variation in shrinkage at different height levels of bamboo culms, different portion in bamboo culms such as outer to inner variation, variation in different age groups of bamboo culms. In addition to this tangential and radial variation in shrinkage also studied. The result shows that a uniform trend in variation was observed based on different parameters.


2012 ◽  
Vol 706-709 ◽  
pp. 271-276 ◽  
Author(s):  
Claudia Carrasco ◽  
C. Montalba ◽  
Carlos Camurri

In the present study, the fabrication of an Al-based metal matrix composite material obtained directly from the melting of the aluminium used beverage cans in a modified rheocasting process is presented. The analysed operational condition is the shear rate applied to the bath and its influence on the properties of the obtained samples. Additionally, samples were heat treated at two different times. The characterization of the phases obtained in Al-based MMC was made by means of metallography, scanning electron microscopy with energy dispersive spectroscopy and electron microprobe with wavelength dispersion spectroscopy. The results show that some constituents were formed during the fabrication process of the MMC, mainly Al6(Fe, Mn), which are partially transformed during the heat treatment. Additionally, samples were evaluated using dynamic mechanical analysis, and the results suggest that the obtained MMC could have very good mechanical properties, similar or superior to the aluminium alloys commonly used for structural applications such as 6XXX family.


2021 ◽  
Vol 1 ◽  
pp. 67-72
Author(s):  
V.S. Yusupov ◽  
◽  
S.I. Tyutyunnikov ◽  
V.A. Artyukh ◽  
T.L. Enik ◽  
...  

By the method of mechanical alloying, compaction and thermosynthesis of a mixture of amorphous boron and aluminum powders, a prototype of highly borated (~50 wt.%) dispersed boron-aluminum was obtained. A comparative assessment of the neutron-shielding properties of borated dispersed aluminum and fibrous boron-aluminum VKM Al-B under irradiation with neutrons with a flux density of 1.4·106 n/cm²·s with a fluence of 3·109 n/cm2 was carried out. Using optical and scanning electron microscopy, a morphological analysis of samples of dispersed-borated powdered aluminum and fibrous-composite boron-aluminum was carried out. It was found that in both materials the level of absorption of neutrons with energies of 0.02-0.05 eV is up to 99.5-99.95%. It is concluded that highly borated dispersed boron-aluminum supplements the line of known boron-containing neutron-absorbing materials with the possibility of using it up to temperatures of 500-700°C.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Avra Kundu ◽  
Maria Gabriela Nogueira Campos ◽  
Swadeshmukul Santra ◽  
Swaminathan Rajaraman

Abstract We demonstrate use of makerspace techniques involving subtractive microtechnologies to fabricate micromilled microneedles (µMMNs) of stainless steel (SS) for precise delivery of agrochemicals into vascular bundles of plant tissue. Precision delivery is of immense importance for systemic pathogen control in specific areas of plant tissue. Optimization of the micromilling allows for selective removal of SS at the microscale and the microfabrication of a 5 × 5 array of µMMNs having both base width and height of 500 µm to enable precise puncture into the stem of citrus saplings. Atomic Absorption Spectroscopy reveals up to 7.5× increase in the uptake of a therapeutic cargo while Scanning Electron Microscopy reveals that specific sites of the vascular bundle; either xylem or the phloem can be uniquely targeted with customized µMMNs. Such rapid and cost-effective customization with intricate designs along with scalability is enabled by makerspace microfabrication. Additionally, a 19 × 20 array of micromilled mesoneedles has been fabricated and affixed to a paint roller as an applicator system for real-world field testing outside the laboratory. Initial results indicate reliable behavior of the applicator system and the technique can be applied to the systemic delivery of agrochemicals while conserving the loss of the agrochemical with increased application efficiency.


2020 ◽  
pp. 152808372093662
Author(s):  
K C Nagaraja ◽  
S Rajanna ◽  
G S Prakash ◽  
G Rajeshkumar

In this work the effect of stacking sequence of Carbon (C)/Glass (G) fibers and halloysites addition (1, 3 and 5 wt.%) on the mechanical and thermal properties of the hybrid composites were explored. The composite laminates were prepared by using Vacuum Assisted Resin Infusion Technique (VARIT). The outcomes disclosed that the hybrid composites having sequence of C2G3C2 (2-Carbon/3-Glass/2-Carbon layers) showed better overall properties. Moreover, the addition of halloysites enhanced the mechanical and thermal properties of the C2G3C2 hybrid composites. In particular, the hybrid composites added with 3 wt.% of halloysites showed higher overall properties among the other hybrid composites investigated. Finally, the morphological analysis was performed on the fractured surface of mechanical tested composites to study the failure mechanisms occurred. Based on the obtained results it can be concluded that the C2G3C2 hybrid composites added with 3 wt.% of halloysite could be a suitable alternative light weight material for automobile, aerospace and building structures.


Phytotaxa ◽  
2018 ◽  
Vol 371 (3) ◽  
pp. 168 ◽  
Author(s):  
MARIE BULÍNOVÁ ◽  
NATALIA KOCHMAN-KĘDZIORA ◽  
KATEŘINA KOPALOVÁ ◽  
BART VAN DE VIJVER

Following an earlier revision of the genus Hantzschia (Bacillariophyta) in the Maritime Antarctic Region, several at present unidentified or poorly known taxa of this aerophilic genus have been investigated using both light and scanning electron microscopy. Based on the morphological analysis of the observations, three new species are currently described: Hantzschia australabundans sp. nov., H. zidarovae sp. nov. and H. zikmundiana sp. nov. The new species differ from comparable taxa in valve outline, structure of the internal proximal raphe endings and structure of the striae and areolae. Additional observations are presented on Hantzschia amphioxys and its forma muelleri, H. abundans and H. incognita, based on observations of Antarctic populations from the South Shetland Islands, Vega Island and James Ross Island. Brief notes on the ecology of all reported species are added.


Author(s):  
Ali J Salman ◽  
Ali Assim Al-Obaidi ◽  
Dalya H Al-Mamoori ◽  
Lina M Shaker ◽  
Ahmed A Al-Amiery

Abstract The polyurethane (PU) has been showing a dramatic increase in applications related to material science and technology. However, the mechanical, physical and thermal properties could be further improved by loading PU with zirconia (Zr) to create renewable materials known as polyurethane–zirconia (PUZ) composites. In this study, PU matrix was treated with wt.% Zr at 0.5, 1.0, 1.5 and 2.0. In this study, the thermo-mechanical properties and the morphology were investigated of PU and PUZ nano-samples. The images of the scanning electron microscope (SEM) were the prime tool in investigating PU and PUZ surfaces and fractured surfaces showing vanishing the cracks and formation of agglomeration on the sample PUZ-1.5%. In addition, the tensile strength, Young’s modulus and maximum loading were improved by 36.7, 31.8 and 39.1%, respectively, at Zr loading of 1.5 wt.%. The flexural stress and the load were improved by 94.3% and 93.6%, respectively, when Zr loading was 1.5 wt.%. The impact without and with a notch was improved by 110.7% and 62.6%, respectively, at Zr loading of 1.5 wt.%. The the morphologies of the PU surface and Zr surface supported by SEM images. Regarding the storage modulus ability of PU and PUZ composites, Zr loading has negatively influenced E. The E functioning temperature was observed to move from 142 to 183°C. Another effect was determined by adding a small amount of Zr. This small amount was enough to shift the crystallization temperature (${T}_c$) and the melting temperature (${T}_m$) of PU from 125 to 129°C and from 150 to 144°C, respectively.


Blood ◽  
1987 ◽  
Vol 69 (2) ◽  
pp. 677-681 ◽  
Author(s):  
DN Podell ◽  
CH Packman ◽  
J Maniloff ◽  
GN Abraham

Abstract The morphology of the amorphous, gelatinous, and crystalline varieties of monoclonal IgG cryoglobulins was analyzed by light and transmission and scanning electron microscopy. Each cryoglobulin had a characteristic fine structure that correlated with its gross morphology. Transmission electron microscopy showed that the amorphous precipitates were random and disorganized molecular clumps. In contrast, cryogels were thin-walled, well-organized, and hydrated strawlike clusters, whereas cryocrystals formed tightly compacted, highly structured molecular clusters. Crystals that formed in blood produced rouleaux, and analysis by scanning electron microscopy indicated that the crystals could form thick-walled, branching, macromolecular nets that could physically trap cells. The morphological properties provided visual impressions by which cryoglobulins could cause clinical disease secondary to vascular occlusion produced by self- associated IgG cryoglobulin molecules.


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