Статті в журналах: "Shell hardness"

1

Freire Andrade, Ariana, and Rodrigo Bíscaro Nogueira. "Caracterización mecánica de conchas amazónicas de Pomacea dolioides (Reeve, 1856)." ACTA ZOOLÓGICA MEXICANA (N.S.) 34, no. 1 (October 29, 2018): 1–11. http://dx.doi.org/10.21829/azm.2018.3412120.

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We investigated the mechanical behavior of freshwater mollusk shells, Pomacea dolioides, collected from a floodplain area located in Amazonas, Brazil. With the purpose of characterizing the mechanical properties of the shells, bending, hardness and roughness tests were carried out. To determine the shell flexural strength, a new methodology was proposed for the calculation of it, considering the curved geometry of the specimens taken from the shells. It was also described the mechanical properties as a function of shell position and thickness, variation of the surface hardness along the shell and the low level of superficial irregularity in the inner layer of the shells. Shell presented a mean flexural rupture modulus (MOR) of 128.0 MPa, Rockwell HR15N hardness = 50 ± 8.3 and a low level of irregularities in the inner layer, roughness Ra = 0.160 μm.

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2

Ikechukwu, I. F., O. S. Onwuka, and M. C. Nwogu. "Production of Periwinkle Shell Reinforced Grindstone." Journal of Applied Sciences and Environmental Management 26, no. 6 (June 30, 2022): 1157–62. http://dx.doi.org/10.4314/jasem.v26i6.24.

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The study involves the use of periwinkle shell particles as reinforcement in the production of grindstone to meliorate its physical and mechanical properties. The assessment of the properties of the periwinkle shell reinforced concrete grindstone showed that reinforcement yielded several promising results. The compressive strength was higher for samples with lower water/cement ratio (7%) than those with higher water/cement ratio (10%). The introduction of concrete that contains periwinkle shells as fine aggregates resulted in the loss of smooth like appearance and reduction in weight. The loss of its smooth like nature introduces the rough nature which improved its functionality. The reinforced sample had the lowest hardness test and in hardness test the lower the number the higher the hardness. There was an increase in the density after absorption test was carried out on specimens. There was also reduction in production cost with periwinkle shells partial replacement of cement and gravel as fine aggregate. The composite was adequate for grindstone production since its sample has a compressive of 18.15Mpa and thus satisfied MOR requirements of 11.5 MPa for general purpose boards.

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3

Ji, Hong Mei, Yun Jiang, Wen Yang, Guang Ping Zhang, and Xiao Wu Li. "Comparisons of Microstructures and Hardness Distribution between Clinocardium Californiense and Veined Rapa Whelk Shells." Key Engineering Materials 544 (March 2013): 295–98. http://dx.doi.org/10.4028/www.scientific.net/kem.544.295.

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Abstract. Microstructures, phase compositions and microhardness distribution of two kinds of natural biological materials called Burnt-end Ark and Veined rapa whelk shells were studied and discussed for comparisons. It was found that the both shells present a hierarchical structure comprising three layers in thickness, i.e., inner, middle and outer layers. The inner and middle layers of the two kinds of shells exhibit cross-lamellar structures with somewhat of differences in the morphology and dimension. The outer layer presents a porous blocky structure for Burnt-end Ark shell and a layered structure for Veined rapa whelk shell. The X-ray diffraction (XRD) analyses show that all the layers of Burnt-end Ark shell as well as the inner and middle layers of Veined rapa whelk consist of crystalline aragonite CaCO3, while the out layer of Veined rapa whelk consists of crystalline calcite CaCO3. The microhardness measurements on the cross sections perpendicular to the growth lines of the shells demonstrate that the hardness of the both shells decreases gradually from the inner layer to the outer layer, strongly depending upon their microstructures.

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4

DANYLUK, MICHELLE D., MARIA T. BRANDL, and LINDA J. HARRIS. "Migration of Salmonella Enteritidis Phage Type 30 through Almond Hulls and Shells." Journal of Food Protection 71, no. 2 (February 1, 2008): 397–401. http://dx.doi.org/10.4315/0362-028x-71.2.397.

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The ability of Salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. First, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a suspension of Salmonella enterica serovar Enteritidis phage type 30 for 24hat24°C. Salmonella Enteritidis was isolated from the inside of these almond shells in 46 and 100% of the samples, by direct swabbing of the inner surface of the shell and by enrichment from the swab, respectively. These findings suggested that hardness of the shell is not a significant factor in the migration of the pathogen through that tissue. In addition, both motile and nonmotile strains of S. enterica serovar Typhimurium migrated through the almond shells to the same extent under the conditions of this assay, indicating that bacterial migration through the wet shell may be a passive process. Second, whole almonds (intact hull, shell, and kernel) were soaked for 24 to 72 h at 24°C in a suspension of Salmonella Enteritidis phage type 30 labeled with the green fluorescent protein. Green fluorescent protein–labeled Salmonella cells were observed on the outer and inner surfaces of both the almond hull and shell, and on the kernel, by confocal laser scanning microscopy. Our data provide direct evidence that wet conditions allow for Salmonella migration through the hull and shell and onto the almond kernel, thus providing a means by which almond kernels may become contaminated in the field.

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5

Handoko, Dwi, Vivaldi Vivaldi, and Sutrisno Sutrisno. "Pengaruh Variasi Jenis Katalisator Dan Holding Time Pada Proses Pack Carburizing Terhadap Perubahan Komposisi Karbon Dan Nilai Kekerasan Baja Karbon Rendah (Low Carbon Steel) St 37." Jurnal Vokasi 16, no. 1 (June 30, 2021): 38–45. http://dx.doi.org/10.31573/vokasi.v16i1.316.

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In this study, a pack carburizing process was carried out on low carbon steel using activated carbon, coconut shell charcoal and various catalysts in the form of ale-ale shells, eggshells, and beef bones. The method used is heating at an austenite temperature of 900 oC with a variation of holding time of 30, 60, and 90 minutes, then quenching using water, followed by hardness testing with the Vickers method and composition testing. The general result is that the three types of catalysts can accelerate the diffusion-reaction so that the carbon addition process occurs and the longer holding time can provide an opportunity for the carbon formed to transform from the pearlite microstructure to the austenite microstructure, and when quenching it forms the Martensite microstructure. Of the three types of catalysts that produced the highest hardness was an ale-ale shell, from the initial hardness 119 HV to 464 HV.

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6

Li, Rui, Yue Pan, Di Chen, Xiangyu Xu, Guangrong Yan, and Tianyuan Fan. "Design, Preparation and In Vitro Evaluation of Core–Shell Fused Deposition Modelling 3D-Printed Verapamil Hydrochloride Pulsatile Tablets." Pharmaceutics 14, no. 2 (February 17, 2022): 437. http://dx.doi.org/10.3390/pharmaceutics14020437.

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The aim of the study was to investigate core–shell pulsatile tablets by combining the advantages of FDM 3D printing and traditional pharmaceutical technology, which are suitable for a patient’s individual medication and chronopathology. The tablets were designed and prepared with the commercial verapamil hydrochloride tablets as core inside and the fused deposition modelling (FDM) 3D-printed shell outside. Filaments composed of hydroxypropylmethyl cellulose (HPMC) and polyethylenglycol (PEG) 400 were prepared by hot melt extrusion (HME) and used for fabrication of the shell. Seven types of printed shells were designed for the tablets by adjusting the filament composition, geometric structure and thickness of the shell. A series of evaluations were then performed on the 3D-printed core–shell tablets, including the morphology, weight, hardness, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), in vitro drug release and CT imaging. The results showed that the tablets prepared by FDM 3D printing appeared intact without any defects. All the excipients of the tablet shells were thermally stable during the extruding and printing process. The weight, hardness and in vitro drug release of the tablets were affected by the filament composition, geometric structure and thickness of the shell. The pulsatile tablets achieved personalized lag time ranging from 4 h to 8 h in the drug release test in phosphate-buffered solution (pH 6.8). Therefore, the 3D-printed core–shell pulsatile tablets in this study presented good potential in personalized administration, thereby improving the therapeutic effects of the drug for circadian rhythm disease.

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7

Skripalenko, Mikhail M., Stanislav O. Rogachev, Boris A. Romantsev, Viacheslav E. Bazhenov, Mikhail N. Skripalenko, and Andrei V. Danilin. "Microstructure and Hardness of Hollow Tube Shells at Piercing in Two-High Screw Rolling Mill with Different Plugs." Materials 15, no. 6 (March 11, 2022): 2093. http://dx.doi.org/10.3390/ma15062093.

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AA6060 ingots were pierced in a two-high screw rolling mill (MISIS-130D) with guiding shoes (Mannesmann mill type). Three different plugs, i.e., a conventional entire plug, a plug with a cavity, and a hollow plug, were used for piercing. We established that the grain size decreases after piercing, by order of magnitude, compared to the initial non-pierced annealed bill, with a grain size of 100–400 μm, and the hollow shell grains are elongated along the piercing direction. The produced hollow shells had 30% higher hardness than the initial billet. The highest hardness values were obtained after piercing the conventional entire plug. The most uniform hardness distribution through the hollow shell’s volume was obtained after piercing the hollow plug. The cross and longitudinal section hardness measurements demonstrate that the hardness decreases from the outer surface to the inner surface of the hollow shells.

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8

Meng, Yuan, Zhenbin Guo, Susan C. Fitzer, Abhishek Upadhyay, Vera B. S. Chan, Chaoyi Li, Maggie Cusack, Haimin Yao, Kelvin W. K. Yeung, and Vengatesen Thiyagarajan. "Ocean acidification reduces hardness and stiffness of the Portuguese oyster shell with impaired microstructure: a hierarchical analysis." Biogeosciences 15, no. 22 (November 16, 2018): 6833–46. http://dx.doi.org/10.5194/bg-15-6833-2018.

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Abstract. The rapidly intensifying process of ocean acidification (OA) due to anthropogenic CO2 is not only depleting carbonate ions necessary for calcification but also causing acidosis and disrupting internal pH homeostasis in several marine organisms. These negative consequences of OA on marine calcifiers, i.e. oyster species, have been very well documented in recent studies; however, the consequences of reduced or impaired calcification on the end-product, shells or skeletons, still remain one of the major research gaps. Shells produced by marine organisms under OA are expected to show signs of dissolution, disorganized microstructure and reduced mechanical properties. To bridge this knowledge gap and to test the above hypothesis, we investigated the effect of OA on juvenile shells of the commercially important oyster species, Magallana angulata, at ecologically and climatically relevant OA levels (using pH 8.1, 7.8, 7.5, 7.2). In lower pH conditions, a drop of shell hardness and stiffness was revealed by nanoindentation tests, while an evident porous internal microstructure was detected by scanning electron microscopy. Crystallographic orientation, on the other hand, showed no significant difference with decreasing pH using electron back-scattered diffraction (EBSD). These results indicate the porous internal microstructure may be the cause of the reduction in shell hardness and stiffness. The overall decrease of shell density observed from micro-computed tomography analysis indicates the porous internal microstructure may run through the shell, thus inevitably limiting the effectiveness of the shell's defensive function. This study shows the potential deterioration of oyster shells induced by OA, especially in their early life stage. This knowledge is critical to estimate the survival and production of edible oysters in the future ocean.

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9

SHUAIB-BABATA, YUSUF LANRE, Ibrahim Owolabi Ambali, Lawal Babatunde Abdulqadir, Hassan Kobe Ibrahim, Ishaq Na’allah Aremu, and Taofeek Olawale Ibraheem. "Production of Abrasive Sandpaper using Periwinkle Shells and Crab Shells." International Journal of Engineering Materials and Manufacture 5, no. 2 (June 25, 2020): 55–61. http://dx.doi.org/10.26776/ijemm.05.02.2020.04.

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In this study, the abrasive properties of periwinkle shell and crab shell grains with the binding effect of polyester resin at high concentration were evaluated. The abrasive properties considered were the hardness, compressive strength and wear resistance. The shells were processed into grit standards by crushing, grinding and then sieving using ASTM E11 set of sieves into grain sizes of P40 and P60. Furthermore on, the grits were developed into polymer matrix composite with particles varying from 96 wt.% to 92 wt.% and resin 3 wt.% to 7 wt.% with 1 wt.% each of cobalt naphthalene and methyl ethyl ketone peroxide hardener respectively by mixing and mold compression using a hydraulic press. It was found that, with an increase in polyester resin content, the hardness and compressive strength increased, while the wear rate decreased. The composition with most improved abrasive properties was 92 wt.% periwinkle shell grains to 7 wt.% polyester resin.

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10

Srikiran, S., Ch Venkatarao, and T. Raviteja. "Fabrication and Mechanical Properties of Hybrid Aluminum Metal Matrix Composite by Using Stir Casting Process." Advances in Science and Technology 106 (May 2021): 17–25. http://dx.doi.org/10.4028/www.scientific.net/ast.106.17.

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An attempt is made to study the influence of dispersion of Groundnut shell ash (GSA) on the hardness and density of Aluminum Metal Matrix Composite. It is an attempt to use agricultural waste in trying to enhance the mechanical properties of the already existing materials. The work deals with the use of groundnut shell ash, mixed with aluminum using stir casting process. . The composites with varying percentage of groundnut shell ash from 0% to 6% were prepared. The prepared specimens were tested before and after the heat treatment process in terms of its hardness using a Rockwell Hardness Tester. The present work attempts to compare the hardness and density of prepared composites as compared to the alloy. The comparison is carried out before and after the heat treatment process. The results indicate the increasing hardness value and reducing density of composites.

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11

Rolence, Cecilia. "Water Hardness Removal by Coconut Shell Activated Carbon." International Journal of Science, Technology and Society 2, no. 5 (2014): 97. http://dx.doi.org/10.11648/j.ijsts.20140205.11.

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12

Kolawole, M. Y., J. O. Aweda, S. Abdulkareem, S. A. Bello, A. Ali, and F. Iqbal. "Influence of calcined snail shell particulates on mechanical properties of recycled aluminium alloy for automotive application." Acta Periodica Technologica, no. 51 (2020): 163–80. http://dx.doi.org/10.2298/apt2051163k.

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Nowadays, low-cost particulate reinforced metal matrix composites with improve mechanical properties are highly sought in various industrial and critical engineering applications including automotive and aerospace sectors. Meanwhile, increasing consumption rate of African giant land snail (Archachatina marginata) had been posing disposal challenges of its shells. Therefore, this paper tends to investigates the influence of waste snail shells particulates on the physical and mechanical properties of recycled aluminum- silicon alloy matrix. Different weight proportions i.e. (0 - 7.5) wt% of calcined snail shell particles at an interval of 1.5 wt% were successfully incorporated into Al-Si alloy matrix melted at 750 ?C using stir-casting route. The microstructure, physical and mechanical properties of the resulting composites were examined and presented. Microstructural examination shows fairly uniform dispersion of snail shell particles in the aluminium alloy matrix intermingled with aluminium-silicon dendrites. Mechanical properties such as hardness, impact, compressive and tensile strengths increased with increasing addition of calcined snail shell particulate up to 6 wt% while density and elongation decreases. The total equivalent density reduction of 5.4% in composites compared to unreinforced alloy was obtained at 7.5 wt% snail shell addition. The maximum hardness, impact, compressive and tensile strengths obtained are 118?4 HV, 88 J, 552?20 MPa and 211 ? 4.8 MPa equivalent to 21, 25, 19 and 36 percent increase respectively relative to un-reinforced aluminium-silicon alloy. Hence, mechanical and physical properties of Al-Si alloy can be enhanced using calcined snail shell particulates which can widen its application in automotive industries.

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13

Bellow, S. A., J. O. Agunsoye, J. A. Adebisi, F. O. Kolawole, and S. B. Hassan. "Physical properties of coconut shell nanoparticles." Kathmandu University Journal of Science, Engineering and Technology 12, no. 1 (November 12, 2018): 63–79. http://dx.doi.org/10.3126/kuset.v12i1.21566.

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Physical properties such as apparent density, bulk density, compressibility index and particle sizes of carbonized and uncarbonized coconut shell nanoparticles produced through top down approach have been studied. Percentage composition of the coconut fruit was determined using five different coconut fruit samples. Results revealed that coir occupies the highest percentage; coconut shells account for 15 % while the flesh and liquid occupy 30 % of the whole coconut fruit. The apparent densities of the uncarbonized and carbonized coconut shell nanoparticles obtained at 70 hours of milling are 0.65 g/cm3 and 0.61 g/cm3 respectively. Their respective compressibility indices and average particle sizes are 46.4 % and 69.7 %; 50.01 nm and 14.29 nm. The difference in the particle sizes of the carbonized and uncarbonized coconut shell nanoparticles can be linked with reduction in the moisture content and volatiles of the carbonized coconut shell nanoparticles due to carbonization process. The reduction in the moisture and volatiles results in the enhanced hardness and brittleness of the carbonized coconut shells which facilitate their breakage during the course of milling than that of the uncarbonized coconut shells. Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016, Page: 63-79

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14

Müller, M., P. Valášek, M. Linda, and S. Petrásek. "Exploitation of Hazelnut (Corylus avellana) Shell Waste in the Form of Polymer–Particle Biocomposite." Scientia Agriculturae Bohemica 49, no. 1 (March 1, 2018): 53–59. http://dx.doi.org/10.2478/sab-2018-0009.

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Abstract Mechanically ground hazelnut (Corylus avellana) shells, a food industry by-product of hazelnuts processing, were tested for use as a composite material filler. Mechanical properties and fracture surface of the composite were evaluated using scanning electron microscopy. Polymer composites, i.e. resins filled with microparticles of hazelnut shells, were tested at various concentrations of the filler (5, 10, 20, 30, and 40 wt%). Hazelnut shell microparticles used at low concentration (5 wt%) increased tensile strength. The filler did not considerably influence hardness of the composite. Adhesive bond strength did not significantly change up to 20 wt%. The hazelnut shell microparticles were well wetted with the resin.

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15

Fitzer, Susan C., Wenzhong Zhu, K. Elizabeth Tanner, Vernon R. Phoenix, Nicholas A. Kamenos, and Maggie Cusack. "Ocean acidification alters the material properties of Mytilus edulis shells." Journal of The Royal Society Interface 12, no. 103 (February 2015): 20141227. http://dx.doi.org/10.1098/rsif.2014.1227.

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Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis , was cultured at projected levels of p CO 2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus ( E ), hardness ( H ) and toughness ( K IC ) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean p CO 2 and temperatures as projected for future global ocean appears to reduce the impact of increasing p CO 2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature.

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16

Rafidah, Rafidah, and Elsa Safitri Muin. "EFEKTIFITAS ARANG TEMPURUNG KELAPA (Cocus nucifera L) DALAM MENURUNKAN KESADAHAN TOTAL PADA AIR." Sulolipu: Media Komunikasi Sivitas Akademika dan Masyarakat 19, no. 1 (August 23, 2019): 1. http://dx.doi.org/10.32382/sulolipu.v19i1.903.

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ABSTRACT One of the chemical parameters in the water requirement is water hardness. Hardness is the term used in water containing the cation causing hardness. In general, hardness is caused by the presence of metals or cations of divalent 2, such as Fe, Sr, Mn, Ca and Mg.The purpose of this research is to know how the effectiveness of coconut shell charcoal in reducing total hardness in water. The type of research conducted is True Experiment with Pretest - Posttest Group Design design that is comparing the decrease of water hardness before and after being treated with coconut shell charcoal medium by using combination of thickness variation and contact time.Based on this research it is known that there is relationship between thickness variation and contact time with decrease of total hardness in water. With the result that is at 10 cm thickness by using time variation 40,50, and 60 minutes obtained by sequence 7.82%, 11.25% and 12.5%. As for the thickness of 20 cm with variations of time 40 minutes, 50 minutes, and 60 minutes obtained results 8.75% sequence, 13.76% and 19.16%. While at 30 cm thickness with time 40 minutes, 50 minutes, 60 minutes sequentially obtained results 22.05%, 27.08% and 33.33%. The conclusion of this research is the variation of thickness and contact time of charcoal and water of sadah able to decrease the hardness. So it can be an alternative in reducing hardness. For further researchers can use or combine other media so that the results of hardness filtration can occur decrease the hardness. Keyword: Hardness, Coconut Shell Charcoal, Charcoal Thickness, Contact Time

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17

Szabó, Balázs P. "Connection Between the Debranning Time and the Kernel Hardness of Wheat." Analecta Technica Szegedinensia 11, no. 1 (January 3, 2017): 16–22. http://dx.doi.org/10.14232/analecta.2017.1.16-22.

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Surface cleaning has an important role in the technology of milling of wheat considering food security. Wheat hardness has an effect on the milling process, it determines the properties, qualities and end use of flours. In the last decade new debranning methods have appeared, which are able to better remove the shell of wheat grains applying rubbing surfaces. In my thesis I examined how different levels of debranning affect hardness and content of ash in wheat types with different grain structure. Conclusion is with approximately 4% of shell removed the hardness of grain. Further removing of shell does not result in further changes though. Reduction of hard wheat’s general grain size with longer debranning process is larger compared to soft wheat’s.

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18

Fornés Comas, Jaume, Rafel Socias i Company, and José M. Alonso Segura. "Shell hardness in almond: Cracking load and kernel percentage." Scientia Horticulturae 245 (February 2019): 7–11. http://dx.doi.org/10.1016/j.scienta.2018.09.075.

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19

Salam Fadhil, Hwazen, and Rusul Salah Hadi. "EROSION WEAR AND HARDNESS SHORE D OF EPOXY RESIN FILLED WITH PISTACHIO POWDER." IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING 21, no. 1 (April 3, 2021): 26–34. http://dx.doi.org/10.32852/iqjfmme.v21i1.536.

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In this research, erosion wear rate and hardness shore D for polymer biocomposite materials were investigated. The present bio-composites made up of differing weight percentage of pistachio shell powder (0%, 5%, 7%, and 9%) with epoxy resin was prepared by hand layout method. The erosion wear rates for bio composites obtained with under constant factors (10 hours, 60º impingement angles, sand silica particles 850μm, standoff distance 23 cm, flow rate 45 L/min, room temperature, nozzle diameter 4mm and pump diameter 50 mm). Results show that the specimen (epoxy + 9% pistachio shell powder) has the best erosion wear rate resistance and hardness shore D compared with other specimens, also the specimen reinforced by 9% pistachio shell have the lower density and highest water absorption percentage and it is found that the improving percentage for the this specimen in hardness is (11.5%) and in erosion wear rate is (775%). The study reveals that the addition of pistachio shell powder to the epoxy reduces its erosion wear rate and semi ductile behavior.

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20

E. E. Sudaria and D. C. Suministrado. "QUASI STATIC MECHANICAL PROPERTIES OF COCONUT SHELL OF DEHUSKED MATURE NUTS." CORD 10, no. 01 (December 1, 1994): 34. http://dx.doi.org/10.37833/cord.v10i01.278.

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The experiment was conducted to determine the (1) cracking, shearing, bending and tensile stresses of coconut shell at different positions of dehusked mature nut; (2) hardness of the coconut shell at different positions of dehusked mature nut; and (3) cracking streBB Of the dehusked mature coconut at different positions. The range values of the parameters under study were as follows: cracking stress of the coconut shell, 3,345, 083.2‑5, 397, 828.3 kg/m2; shearing stress of coconut shell, 574,984.9‑1, 258,830.9 kg/m2; bending stress of the coconut shell, 1,775,213.1‑ 23,463,299.9 kg/m2 , tensile stress of the coconut shell, 61,801.9‑259,003.3 kg/m2, hardness of the coconut shell, 150C51.5-150C57.6; and the cracking stress of the dehusked mature nut, 280,104.0‑440,277.7 kg/m2. The combined average stresses on bending, shearing, tensile, cracking of coconut shell, and cracking of dehusked mature nut revealed no significant difference on stresses at any positions of the dehusked mature nut. This suggests that nuts could be splitted at any position without significant difference on power expenditure. For the design of the splitter machine, cracking stress of the coconut shell should be viewed very well since this parameter had the highest stress.

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21

SUH, CHANG-MIN, and MIN-SOO SUH. "VARIATIONS OF IMPACT VALUE AND HARDNESS FOR ROLL SHELL STEEL AND S25C UNDER VARIOUS TEMPERING." International Journal of Modern Physics B 25, no. 31 (December 20, 2011): 4245–48. http://dx.doi.org/10.1142/s0217979211066684.

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This study carried out a series of experiments viz. impact tests (drop weight & Charpy) and hardness tests after various heat treatments. The fractography observation on normal roll shell steel (NRS), abnormal roll shell steel (ARS), and S25C steel were carried out as well to analyze the cause of brittle fractures and damages in the roll shell steel. The optimal tempering temperature has been characterized for ARS and NRS.

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Anjali, Razia, Anjali, Razia, Shivani Bhandari, Ankur Pant, Arpit Saxena, Seema, Nitin Kumar, Nikhil Chotrani, Dheeraj Gunwant, and P. L. Sah. "Fabrication and Mechanical Testing of Egg Shell Particles Reinforced Al-Si Composites." International Journal of Mathematical, Engineering and Management Sciences 2, no. 1 (March 1, 2017): 53–62. http://dx.doi.org/10.33889/ijmems.2017.2.1-005.

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The production of chicken eggs on a widespread industrial level has led to the generation of a large amount of egg shells. These egg shells are considered to be bio-hazardous waste materials although they are a rich source of amino acids and minerals. In the present investigation, effort has been made to incorporate waste poultry egg shell particles (ESP) both in carbonized (C) as well as uncarbonized (UC) form into the matrix of an Aluminum-Silicon (Al-Si) alloy to improve its mechanical properties. Various mechanical properties of the resulting composites such as tensile strength, modulus of elasticity, hardness, toughness, impact and compressive strengths have been determined and found to increase after the addition of the ESPs confirming that the incorporation of waste ESPs in the Al-Si matrix serve as reinforcements. The increase in mechanical properties such as the hardness (10.2% - UC, 19% - C), tensile (6.61% - UC, 10.61% - C), compressive (9.12% - UC, 63.94% - C) and impact strengths (30.07% - UC, 302.35% - C) is more pronounced in the case of carbonized ESPs. Field-Emission Scanning Electron Microscopy (FE-SEM) has been conducted to determine the compositions of the matrix materials as well as the composites.

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23

Oleiwi, Jawad K., and Rusul S. Hadi. "Study of Polymeric Composite Reinforced with Natural Particles: Measurement and Evaluation." Instrumentation Mesure Métrologie 21, no. 3 (June 30, 2022): 113–17. http://dx.doi.org/10.18280/i2m.210304.

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Natural particles and their composites are important in materials science, where a significant attentiveness is being displayed in the usage of natural particles as reinforcement in polymer composites. The purpose of this research is to investigate the effect of the walnut shell particles as reinforcing fillers in a matrix composite. So, the amount composite examples were advanced through varying the percentage by weight of filler (3, 5, 7, and 9%) in an epoxy and unsaturated polyester polymer. Composite samples were mechanically characterized by tensile tests, flexural tests, hardness tests, and the Izod impact test. The tensile strength and impact strength of epoxy resin were increased after adding organic waste filler. The highest values of tensile strength and impact strength happened at 7% wt. The flexural strength and hardness of shore D increased with the percentage of walnut shell particles. The highest values of flexural strength and hardness were found at 9% wt. The results show that the mechanical properties of epoxy composite are better than the mechanical properties of unsaturated polyester composite when walnut shell particles are added.

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24

Gardnerm, Caleb, and Richard Musgrove. "Quantifying Shell Hardness in the Southern Rock Lobster (Jasus edwardsii)." Journal of Aquatic Food Product Technology 15, no. 2 (July 27, 2006): 17–35. http://dx.doi.org/10.1300/j030v15n02_03.

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25

Igic, Branislav, Kim Braganza, Margaret M. Hyland, Heather Silyn-Roberts, Phillip Cassey, Tomas Grim, Jarkko Rutila, Csaba Moskát, and Mark E. Hauber. "Alternative mechanisms of increased eggshell hardness of avian brood parasites relative to host species." Journal of The Royal Society Interface 8, no. 64 (May 11, 2011): 1654–64. http://dx.doi.org/10.1098/rsif.2011.0207.

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Obligate brood parasitic birds lay their eggs in nests of other species and parasite eggs typically have evolved greater structural strength relative to host eggs. Increased mechanical strength of the parasite eggshell is an adaptation that can interfere with puncture ejection behaviours of discriminating hosts. We investigated whether hardness of eggshells is related to differences between physical and chemical traits from three different races of the parasitic common cuckoo Cuculus canorus , and their respective hosts. Using tools developed for materials science, we discovered a novel correlate of increased strength of parasite eggs: the common cuckoo's egg exhibits a greater microhardness, especially in the inner region of the shell matrix, relative to its host and sympatric non-host species. We then tested predictions of four potential mechanisms of shell strength: (i) increased relative thickness overall, (ii) greater proportion of the structurally harder shell layers, (iii) higher concentration of inorganic components in the shell matrix, and (iv) elevated deposition of a high density compound, MgCO 3 , in the shell matrix. We confirmed support only for hypothesis (i). Eggshell characteristics did not differ between parasite eggs sampled from different host nests in distant geographical sites, suggesting an evolutionarily shared microstructural mechanism of stronger parasite eggshells across diverse host-races of brood parasitic cuckoos.

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Ohmi, Tatsuya, and Manabu Iguchi. "Solidification Structure and Hardness Distribution in Centrifugally Cast Aluminum Alloy Duplex Pipes." Materials Science Forum 631-632 (October 2009): 367–72. http://dx.doi.org/10.4028/www.scientific.net/msf.631-632.367.

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The solidification structure and hardness distribution in aluminum alloy duplex pipes produced by a two-step centrifugal casting have been investigated. In this process, two kinds of molten metals, i.e., the first melt and the second melt with a higher liquidus temperature were cast in sequence at a given interval into a rotating mold of a centrifugal caster. An Al-12mass%Si alloy was used for the first melt, and an Al-30mass%Ni or Al-32mass%Si-0.1mass%P alloy was used for the second melt. The second melt was cast after the solidified shell of the first melt had formed. The resultant cast pipes consisted of an outer side layer and a composite layer containing fine primary crystals. The outer side layer was a portion of the solidified shell of the first melt that survived after the contact with the higher-temperature second melt. The composite layer consisted of one or two layer(s). When the volume of the remelted part of the solidified shell was large, all the second melt mixed into the first melt and the resulted mixed melt formed the composite layer. On the other hand, the composite layer formed only from the second melt when the temperature of the solidified shell was low. In the intermediate case, the composite layer consisted of these two types of the layers.

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PUTZ, MIHAI V. "SEMICLASSICAL ELECTRONEGATIVITY AND CHEMICAL HARDNESS." Journal of Theoretical and Computational Chemistry 06, no. 01 (March 2007): 33–47. http://dx.doi.org/10.1142/s0219633607002861.

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The semiclassical path integral approach is undertaken to develop new definitions and atomic scales of electronegativity and chemical hardness. The considered quantum probability amplitude up to the fourth-order expansion provides intrinsic electronegativity and chemical hardness analytical expressions in terms of principal quantum number of the concerned valence shell and of the effective atomic charge including screening effects. The present electronegativity scale strikes on different orders of magnitude down groups of the periodic table, while still satisfying the main required acceptability criteria regarding the finite difference–based scale. The actual chemical hardness scale improves the trend across periods of the periodic system, avoiding the usual irregularities within the old-fashioned energetic picture. The current quest introduces the electronegativity of an element as the power by which the frontier electrons are attracted to the center of the atom being a stability measure of the atomic system as a whole.

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28

Yönetken, Ahmet, Ayhan Erol, and Günnur Peşmen. "Characterization of egg shell powder-doped ceramic–metal composites." Open Chemistry 20, no. 1 (January 1, 2022): 716–24. http://dx.doi.org/10.1515/chem-2022-0175.

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Abstract Titanium is known to be an indispensable element in biomaterials. In this study, boron carbide was considered as an alternative to titanium due to its good mechanical properties. Boron carbide has high temperature resistance, high wear resistance, etc. It is a preferred material due to its properties. Considering this information, different compositions were created by mixing Fe–B4C and egg shell powders. Compositions sintered using powder metallurgy technique were investigated mechanically, physically and metallographically. According to the results of the analysis, it was determined that the hardness increased by 13.75% with the addition of egg shell. The hardness value of 204.12 HB was measured in the sample sintered at 1,400°C by adding 6.66% egg shelter powder.

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Mehditabar, Aref, Gholam H. Rahimi, and Seyed Ebrahim Vahdat. "Mechanical Properties of Al 25 wt.% Cu Functionally Graded Material." Science and Engineering of Composite Materials 26, no. 1 (January 28, 2019): 327–37. http://dx.doi.org/10.1515/secm-2019-0014.

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AbstractThe present work refers to describe the effects of Al2Cu variations on various properties of thick-walled functionally graded (FG) cylindrical shell. Al-25 wt.% Cu hypo-eutectic alloy ingot is melted and centrifugally casted to obtain high entropy FG composite. A series of microstructure examinations such as FESEM and EDX analysis were carried out to determine the distributions of constituent phases and elements. It is revealed that the maximum volume fraction of Al2Cu particle is reached near the inner surface with 35.7 Vol.% and then reduces gradually to 32.5 Vol.% at the outer surface of FG cylindrical shell. The effects of the variations Al2Cu along radial direction of FG tube are discussed through Vickers hardness, wear rate, coefficient of thermal expansion and compressive test measurements. The experimental results show that the wear and hardness are varied in graded manner which the highest wear resistance with wear rate of 9.1×10−5g/mm2 and hardness with 153HV are found towards Al2Cu enriched zone or inner periphery. Moreover, the studied FG cylindrical shell shows drop 2.5% in yield stress and 4.5% in elastic modulus from intermediate to inner layers due to Al2Cu particles clustering in metal matrix.

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Belyaev, Dmitry, Alexey Aleksandrov, Yuri Zuyev, Eugene Kozlov, Igor Svyatov, and Catherine Levi. "Structure of U-Zr-Mo alloy shell after explosive loading." EPJ Web of Conferences 183 (2018): 03025. http://dx.doi.org/10.1051/epjconf/201818303025.

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This presentation describes investigation of a thick-wall spherical shell 48 mm in diameter from the alloy of uranium with molybdenum and zirconium, which survived after high-intensity explosive loading. Investigation was performed in the meridional section of the shell to obtain qualitative data on hardness and microhardness, metallurgical inclusions, damage, and also material microstructure. Structural changes are observed to widely present in the shell material. The localized damage observed both at R ≈ 12-14 mm and R ≈ 16-18 mm are the first and second converged spalls, respectively. What is more, in the southern sector the first spall was recompacted with the remelting of a large region of the material in the adjacent layers (region with the enhanced hardness for the first spall). Cracks of the second spall in the northern sector were also recompacted almost completely.

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Oinu, Oinu Timothy, D. T. Gundu Gundu, and G. B. Nyior Nyior. "EVALUATION OF COW BONE AND SNAIL SHELL FOR SURFACE TREAMENT OF LOW CARBON STEEL." Natural Science Journal 3, no. 1 (July 18, 2022): 1–11. http://dx.doi.org/10.47941/nsj.932.

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Purpose: In this study, selected calcareous wastes (cow bone and snail shell) were evaluated for use in surface carburizing of low carbon steel. Methodology: Pack carburization process was used for the surface hardening of mild steel at 800 oC as the carburizing temperature. The soaking period of 2 hours was used and water was used as quenching medium. The specimens were subsequently tempered at 500. Mechanical tests such as hardness, impact, microstructural and wear resistance were carried out on the samples using standardized methods. Results: The results obtained showed that the sample carburized with snail shell gave a higher hardness value than sample carburized with cow bone and untreated sample. In the charpy impact test carried out, it was observed that the sample carburized by snail shell has higher energy value than sample carburized with cow bone. For microstructural analysis test, it was seen that sample carburized by cow bone gave equiaxed and finer grains than sample carburized with snail shell and untreated sample, and for wear rate test, sample carburized by snail shell, has a better wear rate than sample carburized by cow bone and untreated sample.

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Donahue, Darrell W., and Robert C. Bayer. "Effects of Diet on Weight Gain and Shell Hardness of New-Shell American Lobster,Homarus americanus." Journal of Applied Aquaculture 8, no. 2 (May 27, 1998): 79–85. http://dx.doi.org/10.1300/j028v08n02_08.

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Inegbedion, F., L. C. Igbonazobi, A. O. Imasuen, and C. O. Inetianbor. "CHARACTERIZATION OF LOW DENSITY POLYETHYLENE WASTE FILLED WITH PALM KERNEL SHELL." International Journal of Engineering Technologies and Management Research 8, no. 4 (April 28, 2021): 71–78. http://dx.doi.org/10.29121/ijetmr.v8.i4.2021.918.

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All over the world, polyethylene wastes has been found littered on the streets of most communities and states. Palm kernel shell (agricultural waste) constitutes dirt and environmental pollution. The aim of this research was to study the potentials of palm kernel shell (PKS) filler as reinforcement for low density polyethylene (LDPE) waste. LDPE-Palm kernel shell composites of varying ratio (100:0, 90:10, 80:20, 70:30, 60:40, 50:50) of LDPE to PKS respectively were produced using the compression moulding technique. Mechanical properties such as water absorption, hardness, young’s modulus and tensile strength of the composites were found to increase with increasing PKS loading. The results showed that composites containing 40% of PKS gave the highest tensile strength corresponding to 18.42MPa. The results also indicated that the composites with 50% filler loading gave the highest hardness of 84.25A and water absorption rate which stood at 3.1%. The elongation at break was found to decrease with increasing filler content. The scanning electron micrograph (SEM) obtained revealed that the composites with 20% and 50% palm kernel shell had voids and surface cracks.

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Schmahl, W. W., E. Griesshaber, C. Merkel, K. Kelm, J. Deuschle, R. D. Neuser, A. J. Göetz, A. Sehrbrock, and W. Mader. "Hierarchical fibre composite structure and micromechanical properties of phosphatic and calcitic brachiopod shell biomaterials — an overview." Mineralogical Magazine 72, no. 2 (April 2008): 541–62. http://dx.doi.org/10.1180/minmag.2008.072.2.541.

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AbstractBrachiopods are a phylum of shell-forming sessile marine invertebrates which have existed since the early Cambrian. Two very different biomaterial design strategies for their shells evolved early in their history. Both strategies use hybrid fibre composites, however, one is based on mineral fibres embedded in ~2 wt.% of organic biopolymer sheaths and the inorganic fibres are calcite single crystals. In the second strategy the fibres are biopolymers and are reinforced with Ca-phosphate nanoparticles to form a fibrous nanocomposite. Here the organic component (chitin) dominates. The Ca-phosphate nanoparticle-reinforcement strategy is not unlike that in vertebrate bone, however, the microscale structure is laminated with alternating laminae which have a different degree of mineralization.The calcitic shells feature an outer compact layer of calcite micro- and nanoparticles protecting the inner fibrous layer from the outside. Transmission electron microscopy of the fibrous layer reveals intercrystalline and intracrystalline biopolymers. The calcitic shell material is stiff with nano-indentation E-moduli of 63±8 GPa and relatively hard (Vickers microhardness up to 400 HV 0.0005/10 and nanohardness 4±0.5 GPa). Compared to inorganic calcite the microhardness is doubled and the nanohardness increases by 60%. We attribute this increased hardness to intracrystalline biopolymers. The nano-indentation E-moduli of the chitinophosphatic shells range from 3 to 55 GPa as a result of the varying degree of mineralization between their laminae, and similarly their nanohardness varies between 0.1 and 3 GPa. For brachiopods burrowing inside the sediment, the alternation of non-mineralized laminae with thin, more strongly mineralized laminae provides abrasion-resistance, hardness and longitudinal stiffness while it preserves the flexibility provided by the organic component for bending movements.

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Ethmane, Isselem Arbih, and Ahmed Yahfdhou. "EFFECT OF ALMOND SHELL PARTICLES ON TENSILE PROPERTY OF PARTICLEBOARD." Chemistry & Material Sciences Research Journal 2, no. 2 (June 23, 2020): 51–54. http://dx.doi.org/10.51594/cmsrj.v2i2.94.

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The objective of the study was to fabricate particleboard using almond shell. The significance of the study is that it can result in creating raw material for panel industry which is in shortage these days. Different particleboards were made based on almond shell particles ratios mixed with epoxy resin. In this study, we investigated the resulting shell particleboard tensile properties. Results shows that when added with almond shell, the tensile properties of the resulting panel showed greater performance. For example, it showed better hardness which is a desirable quality.

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36

Pramuko Ilmu Purboputro, Patna Partono, and Radix Ekaputra. "The analysis of carbon carburizing of ST 60 steel with 80 mesh due to hardness and microstructure." JTTM : Jurnal Terapan Teknik Mesin 3, no. 2 (October 31, 2022): 80–88. http://dx.doi.org/10.37373/jttm.v3i2.297.

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ST 60 steel is a steel with a medium carbon content of about 0.56% by weight. The process will affect the amount of carbon that will be diffused on the surface when the carburizing process is carried out. Different types of carbon from materials and finer carbon grains, it is hoped that carbon diffusion will easily occur. In this study, carbon grains were made with a mesh size of 80, from variations of coal, coconut shell carbon, mangrove tree carbon to microstructure and hardness in ST60 steel material. The method carried out is to heat the ST 60 steel which is inserted in a pack of carbon powder until 900 °C is held for 60 minutes. After that, room temperature cooling is carried out so that carbon atoms are still diffused until the temperature is completed. The tests carried out microstructure (SEM) on raw materials formed pearlite and ferrite phases, after pack carburizing the phase formed pearlite, ferrite and coated by graphite from carbon atoms caused the hardness of the specimen to increase in the pearlite phase exposed to carbon. The results of the Rockwell Hardness test on raw material 52.3 HRA after the pack carburizing process, the hardness of the material has increased which is found in coal carbon of 62.2 HRA, coconut shell carbon of 64.8 HRA and mangrove carbon of 60.7 HRA from the test. The chemical composition of the results obtained in the raw material condition of 0.404 when in pack carburizing increased each material’s coal carbon by 0.829, coconut shell carbon by 0.88, mangrove carbon by 0.76. The largest intake of carbon when pack carburizing compared to the largest is in the pack carburizing with coconut shell charcoal.

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Bello, Sefiu Adekunle. "Coconut Shell Particle Reinforced Al-Cu-Mg Nanocomposites for Cavity Die Mould Parts Applications." International Journal of Engineering Research in Africa 61 (July 25, 2022): 79–94. http://dx.doi.org/10.4028/p-29l8h7.

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This study explored coconut shells in developing Al-Cu-Mg based nanocomposites for fabricating mould parts. The aim is to engineer alternate way through which income can be generated from agricultural wastes and recycling of industrial waste like aluminium cans. Al-Cu-Mg based nanocomposites were produced and characterised. Effects of carbonised and uncarbonised coconut shell nanoparticle (UCSNP) additions on properties of Al-Cu-Mg nanocomposites were compared. Maximum tensile strength was obtained at 10%vol uncarbonised coconut shell nanoparticle additions to Al-Cu-Mg. Increase in tensile strength and elastic modulus were noted with carbonised coconut shell reinforced Al-Cu-Mg nanocomposites against the decrease in the elastic (Young’s) modulus of the UCSNP/Al-Cu-Mg nanocomposites. Despite highest tensile strength of 10%volUCSNP/Al-Cu-Mg, 10%volCCSNP/Al-Cu-Mg nanocomposite is ranked as the best material in this study due to its optimum combination of properties including tensile strength, elastic modulus, tensile strain, impact energy and hardness values. Hence, it has been selected for fabricating open die mould parts to be used in compression sheet forming process for fabricating polymeric standard samples for tensile flexural analyses. Keywords: Al-Cu-Mg, Coconut, Shell, Nanoparticles, Mould fabrication

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38

Ramli, Chung-Chun Wu, and Adel Shaaban. "Mechanical Properties of Pack Carburized SCM 420 Steel Processed Using Natural Shell Powders and Extended Carburization Time." Crystals 11, no. 9 (September 18, 2021): 1136. http://dx.doi.org/10.3390/cryst11091136.

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The feasibility of using coconut shell powder (CSP) and dog conch shell powder (DCSP) as carburizing media in the pack carburization of SCM 420 steel was investigated. The carbon content and surface hardness of the carburized specimens prepared with different CSP:DCSP ratios and carburizing durations were examined and compared. A CSP:DCSP ratio of 60%:40% and an extended carburizing time of 12 h were found to increase the carbon content of the carburized specimens to 1.14 ± 0.007 wt%. Furthermore, the surface hardness was significantly improved to 961.3 ± 4.918 HV following water quenching. Finally, the thickness of the carburized layer of the quenched specimens increased by around 2.5 times as the carburizing duration was increased from 3 to 12 h.

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OTOGURO, Chikao, Sachiko ODAKE, Kyoko TSUJI, and Kentaro KANEKO. "Effect of Ashed Egg Shell on Hardness of Brined Ume Fruit." NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI 42, no. 5 (1995): 353–61. http://dx.doi.org/10.3136/nskkk.42.353.

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40

Yang, Wenk, Guangping Zhang, Huasai Liu, and Xiaowu Li. "Microstructural Characterization and Hardness Behavior of a Biological Saxidomus purpuratus Shell." Journal of Materials Science & Technology 27, no. 2 (February 2011): 139–46. http://dx.doi.org/10.1016/s1005-0302(11)60039-x.

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41

Politzer, Peter, Jane S. Murray, Monica C. Concha, and Ping Jin. "An Operational Definition of Relative Hardness." Collection of Czechoslovak Chemical Communications 72, no. 1 (2007): 51–63. http://dx.doi.org/10.1135/cccc20070051.

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After a brief review of polarizability, charge capacity and hardness, we look at some of the consequences of the requirement, in density functional theory, that the chemical potential and hardness be evaluated with the nuclear potential being held constant. The effects of this can be quite significant, one of them being that some molecules, especially closed-shell, may have zero chemical potentials. We propose that hardness be defined operationally through its inverse relationship to polarizability. Drawing upon correlations found earlier for the latter property, we present a formula for relative hardness in terms of the volume of a molecule and the average local ionization energy on its surface. The formula can also be applied to molecular components, e.g. functional groups, and we show - within the context of this approach - how their contributions combine to yield the hardness of the molecule. This involves a leveling-off effect that explains the relatively small range of hardness values obtained for a group of 33 molecules.

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Orisadare, Oluseyi, Ayodeji S. Olawore, Michael O. Ibiwoye, Eyitayo A. Ponle, Omolola T. Odeyemi, and Opeyemi S. Kegbeyale. "MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF BRASS REINFORCED WITH COCONUT SHELL ASH POWDER." FUTA JOURNAL OF ENGINEERING AND ENGINEERING TECHNOLOGY 15, no. 2 (November 29, 2021): 234–43. http://dx.doi.org/10.51459/futajeet.2021.15.2.270.

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Metal matrix composites (MMCs) are materials in which metals are reinforced with other materials preferably of lower cost to improve their properties. In this present study, Brass /Coconut Shell Ash powder (CSAp) composites having 0%, 5%, 10% and 15% weight CSAp were fabricated by stir-casting method. The tensile strength of the MMCs is in the order 15% > 10% >5% > 0% of CSAp. Hardness of the MMCs increases slightly with increase in the percentage body weight of CSAp, in the order 15% > 10% >5% > 0% of CSAp. The highest impact energy of 61 J was obtained for 5% CSAp. However, significant improvement in tensile strength and hardness values was noticeable at the 15%. Scanning Electron Microscopy (SEM) analysis of the MMCs shows dendritic structures formation, the reinforcing particles (CSAp) are visible and clearly delineated in the microstructure. Hence, this study has established that reinforcing brass matrix with coconut shell ash particles can result in the production of low cost brass composites with enhanced tensile strength, hardness and impact energy values.

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Al-Zubaidi, Aseel Basim. "Mechanical and thermal properties of cockles shell cementing material." Iraqi Journal of Physics (IJP) 13, no. 26 (February 10, 2019): 107–11. http://dx.doi.org/10.30723/ijp.v13i26.290.

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Mortar of ordinary Portland cement was blended with cockles shellpowder at different weight ratios to investigate the effect of powderadmixture on their strength and thermal conductivity. Results showedthat addition of cockles shell powder at 50% of mortar weightimproves hardness and compressive strength notably and reduces thethermal conductivity of the end product. Results suggest thepossibility to incorporate cockles shell powders as constituents incement mortars for construction and plastering applications.

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Ukeje, Chukwudike, Saliu Seidu, Sheriff Saka, Daniel Patrick, and Ubong Essien. "Influence of Palm Kernel Shell Powder on the Mechanical Properties of Inoculated Gray Cast Iron." Advanced Technologies & Materials 47, no. 1 (June 15, 2022): 5–10. http://dx.doi.org/10.24867/atm-2022-1-002.

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The use of agricultural by-products and waste materials as fillers and additives to produce different mix designs with enhanced properties is one of the ways researchers are shifting focus to seek and develop materials that rely on renewable resources. The present research investigates the influence of Palm Kernel Shell Powder (PKSP) on the mechanical properties of inoculated Gray Cast Iron (GCI). Five specimens consisting of sample C0 (0.3%FeSi, 0%PKSP), Sample C3 (0.3%FeSi, 0.3%PKSP), sample C6 (0.3%FeSi, 0.6%PKSP), sample C9 (0.3%FeSi, 0.9%PKSP), and sample C12 (0.3%FeSi, 1.2%PKSP) were developed using sand mold casting method, the chemical analysis, and their mechanical properties (tensile, hardness, and microstructures) were evaluated. The chemical composition shows that the produced gray cast iron solidified within the hypereutectic cast iron range (Carbon Equivalent, CE > 4.5), while the microstructure reveals through the graphite flakes distribution that the produced gray cast iron consists of type A graphite. The highest tensile strength and hardness values were observed in sample C3 with tensile strength and hardness values of 155.97MPa and 156.74 BHN respectively. From the result obtained, an increase in both tensile and hardness values was observed up to 0.3% PKSP addition, beyond this amount, shows a decrease in both tensile strength and hardness values for the developed gray cast iron samples.

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45

Mohan, TP, and K. Kanny. "Thermal, mechanical and physical properties of nanoegg shell particle-filled epoxy nanocomposites." Journal of Composite Materials 52, no. 29 (May 2, 2018): 3989–4000. http://dx.doi.org/10.1177/0021998318773445.

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This work involves the study of the thermal, mechanical and physical properties of epoxy filled with nanoegg shell particles. Nanoegg shell particles of near uniform size and shape were prepared by high-speed ball milling technique. The influence of nanoegg shell particle concentration (1 to 5 wt.%) on epoxy curing rate, thermal stability, dynamic mechanical properties and the tensile, hardness, impact and water uptake properties was evaluated. The result showed improvement in most of these properties except for storage modulus in the rubbery phase. Microscopic examination revealed strong particle–matrix adhesion strength, with optimum improvement of all properties at 2 wt.% nanoegg shell filler concentration.

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46

Kumar, Rajesh, IPS Ahuja, and Rupinder Singh. "Experimental and Analytical Analysis of Light Alloy Shell Castings Using Three Dimensional Printing." International Journal of Advance Research and Innovation 2, no. 3 (2014): 139–53. http://dx.doi.org/10.51976/ijari.231422.

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Growth of rapid prototyping (RP) technologies has proven highly significant in efforts to reduce the production time for a number of casting processes. Lot of research has been done in production of sacrificial sand moulds used in investment casting. This paper systematically presents procedure of producing shell casting using light alloys in ceramic moulds created with three dimensional printing (3DP). The shells are made using special sand provided by Z-Corporation for production of easy and economical shell moulds with creation of 3D printers. Selected part was designed using UNIGRAPHICS modeling software. The moulds using the CAD model were produced with ZCorp 510 RPT machine. An experimental and analytical investigation was conducted to establish the influence of parameters like Layer thickness (Lt), Post curing time (Pc), orientation (O) for printing of shell. Light alloy shell castings using aluminium, zinc and lead were produced with the developed moulds. The effect of other parameters like the shell wall thickness (SWT), weight density (WD) and pouring temperatures (PT) on mechanical characteristics like hardness, dimensional accuracy and international tolerance (IT) grades of castings was also analyzed experimently. The paper concludes feasibility to reduce the shell wall thickness from 12 mm to 2 mm with dimensional accuracy. Consistencies with the permissible range of tolerance grades were achieved. Further at optimised SWT 5 mm, 5 mm and 6 mm, production cost has been reduced by 54.28%, 54.28% and 49.12% and production time has been reduced by 46.05%, 46.28% and 43.42% respectively in comparison to 12mm recommended shell thickness for selected light alloys.

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Prabowo, Herwidhi Tri, Sulhadi Sulhadi, Mahardika Prasetya Aji, and Teguh Darsono. "SIFAT MEKANIK BAHAN KOMPOSIT KAMPAS REM BERBAHAN DASAR SERBUK ARANG KULIT BUAH MAHONI." SPEKTRA: Jurnal Fisika dan Aplikasinya 2, no. 2 (October 17, 2017): 127. http://dx.doi.org/10.21009/spektra.022.06.

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Mahogany bark is one of natural material which not used optimally in society. The overabundance of mahogany bark appearing new problem of garbage which charges an alternative solution creatively and innovatively becomes a new efficient and effective product. An alternative solution of mahogany bark utilization is as organic composite material of disk brake. The making of organic composite material of brake disk firstly is reducing the mahogany bark becomes a homogeneous carbon powder. The mahogany bark was smoked being of carbon and mixed with coconut shell and resin polyester as an adhesive. The organic composite material was produced, tested by Brinell Hardness test and attrition test by varied of composition percentage. There are five kinds of composite material composition had been tested. The result is obtainable of the most precise composition percentage 60% mahogany bark carbon, 15% coconut shell carbon, and 25% resin polyester which has brinell hardness number and attrition massa identically with Standar Nasional Indonesia (SNI). Keywords: mahogany bark, composite material, disk brake, Brinell hardness test, attrition test

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MODESTIN, Emma. "Morphological variations of the shell of the bivalve Lucina pectinata (Gmelin, 1791)." JOURNAL OF ADVANCES IN BIOLOGY 10, no. 2 (September 27, 2017): 2092–107. http://dx.doi.org/10.24297/jab.v10i2.6355.

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In Martinique, the species Lucina pectinata (Gmelin, 1791) is called "mud clam, white clam or mangrove clam" by bivalve fishermen depending on the harvesting environment. Indeed, the individuals collected have differences as regards the shape and colour of the shell. The hypothesis is that the shape of the shell of L. pectinata (P. pectinatus) shows significant variations from one population to another. This paper intends to verify this hypothesis by means of a simple morphometric study. The comparison of the shape of the shell of individuals from different populations was done based on samples taken at four different sites. The standard measurements (length (L), width or thickness (E - Ã©paisseur) and height (H)) were taken and the morphometric indices (L/H; L/E; E/H) were established. These indices of shape differ significantly among the various populations. This intraspecific polymorphism of the shape of the shell of P. pectinatus could be related to the nature of the sediment (granulometry, density, hardness) and/or the predation. The shells are significantly more elongated in a loose muddy sediment than in a hard muddy sediment or one rich in clay. They are significantly more convex in brackish environments and this is probably due to the presence of more specialised predators or of more muddy sediments.

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Yu, Lian Qing, Kai Tuo Dong, Qian Qian Zhi, and Ming Jiang Cai. "Oil Column Method for Magnetic Microspheres with Core-Shell Structure." Materials Science Forum 743-744 (January 2013): 677–80. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.677.

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Spherical alumina catalysts have been widely used in fluidized bed and slurry-bed or catalyst carrier due to their excellent pore structure, large surface area, good physical strength and resistance to acids and stability. Magnetic microspheres of γ-Fe2O3 @ Al2O3 with core-shell structure were obtained by γ-Fe2O3 magnetic core coating with aluminum sol. After aging, drying and calcinations process, microspheres with certain hardness and magnetic properties can be obtained. During the preparation of core-shell structure microspheres, effect of both the content of aluminum sol, hexamethylenetetramine(HMT), magnetic core γ-Fe2O3 and process parameters of shaping time, aging temperature, calcination temperature on the properties of the spherical carrier was investigated. The optimum properties of microsphere carrier for hardness of 36.32 N/mm, specific surface area of 89.016 m2/g, pore volume of 0.874 cm3/g and average pore diameter 18.51 nm were synthesized, respectively.

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50

Strąg, Martyna, Łukasz Maj, Magdalena Bieda, Paweł Petrzak, Anna Jarzębska, Jürgen Gluch, Emre Topal, et al. "Anisotropy of Mechanical Properties of Pinctada margaritifera Mollusk Shell." Nanomaterials 10, no. 4 (March 28, 2020): 634. http://dx.doi.org/10.3390/nano10040634.

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The mechanical properties such as compressive strength and nanohardness were investigated for Pinctada margaritifera mollusk shells. The compressive strength was evaluated through a uniaxial static compression test performed along the load directions parallel and perpendicular to the shell axis, respectively, while the hardness and Young modulus were measured using nanoindentation. In order to observe the crack propagation, for the first time for such material, the in-situ X-ray microscopy (nano-XCT) imaging (together with 3D reconstruction based on the acquired images) during the indentation tests was performed. The results were compared with these obtained during the micro-indentation test done with the help of conventional Vickers indenter and subsequent scanning electron microscopy observations. The results revealed that the cracks formed during the indentation start to propagate in the calcite prism until they reach a ductile organic matrix where most of them are stopped. The obtained results confirm a strong anisotropy of both crack propagation and the mechanical strength caused by the formation of the prismatic structure in the outer layer of P. margaritifera shell.

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