Cementation of Soil Due to Carbonate Production in the Presence of Oyster Shell

Author(s):  
Motohei Kanayama ◽  
Masataka Akashi ◽  
Masami Ohtsubo ◽  
Takahiro Higashi
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
M.S. Hamzah

The growth of pearl shell oyster is influenced by nacre availability consisting of calcium carbonate. Nacre is identified as a protein metabolism product in pearl oyster. The aim of this study was to evaluate the effects of media level pressure in larva rearing tank on protease enzyme activity to promote growth performance and survival rate of Pinctada maxima larvae. The research was conducted from March 6th to May 7th 2015 in laboratorium of Mataram Marine Bio Industry Technical Implementation Unit, LIPI. “Chi-Square” test showed that survival rate of larvae at Umbo-veliger stage (planktonic) was significantly affected by water level pressure within 99% with ratio 1.00:1.61. In contrast, treatment with no water level pressure also significantly influenced the survival rate of larvae in spat stage within 99% confidence with ratio of 1.00:1.93. The highest average survival rate of larvae in umbo-veliger and spat stages were 13.10% and 2.60%, respectively. The effect of protease enzyme activity on calcium carbonate production to produce oyster shell are also discussed in this paper. Keywords:  water level pressure, protease enzyme activity, survival rate, growth, larvae, P. maxima


2016 ◽  
Vol 13 (4) ◽  
pp. 1223-1235 ◽  
Author(s):  
Mathias Harzhauser ◽  
Ana Djuricic ◽  
Oleg Mandic ◽  
Thomas A. Neubauer ◽  
Martin Zuschin ◽  
...  

Abstract. We present the first analysis of population structure and cohort distribution in a fossil oyster shell bed based on 1121 shells of the giant oyster Crassostrea gryphoides (von Schlotheim, 1813). Data derive from terrestrial laser scanning of a Lower Miocene shell bed covering 459 m2. Within two transects, individual shells were manually outlined on a digital surface model and cross-checked based on high-resolution orthophotos, resulting in accurate information on center line length and area of exposed shell surface. A growth model was calculated, revealing this species as the fastest growing and largest Crassostrea known so far. Non-normal distribution of size, area and age data hints at the presence of at least four distinct recruitment cohorts. The rapid decline of frequency amplitudes with age is interpreted to be a function of mortality and shell loss. The calculated shell half-lives range around a few years, indicating that oyster reefs were geologically short-lived structures, which could have been fully degraded on a decadal scale. Crassostrea gryphoides reefs were widespread and common along the Miocene circum-Tethyan coasts. Given its enormous growth performance of  ∼  150 g carbonate per year this species has been an important carbonate producer in estuarine settings. Yet, the rapid shell loss impeded the formation of stable structures comparable to coral reefs.


2016 ◽  
Vol 7 (2) ◽  
Author(s):  
M.S. Hamzah

<p><em>The growth of pearl shell oyster is influenced by nacre availability consist</em><em>ing</em><em> of calcium carbonate. Nacre is identified as a protein metabolism product in pearl oyster. The aim of this study was to evaluate the effects of media level pressure in larva rearing tank on protease enzyme activity to promote growth performance and survival rate of <span style="text-decoration: underline;">Pinctada</span> <span style="text-decoration: underline;">maxima</span> larvae. The research was conducted from March 6<sup>th</sup> to May 7<sup>th</sup> 2015 in laboratorium of Mataram Marine Bio Industry Technical Implementation Unit, LIPI. “Chi-Square” test showed that survival rate of larvae at Umbo-veliger stage (planktonic) was significantly affected by water level pressure within</em><em> </em><em>99% with ratio 1.00:1.61. In contrast, </em><em>treatment with no </em><em>water level pressure </em><em>also </em><em>significantly </em><em>influenced the</em><em> survival rate of larvae in spat stage within 99% confidence with ratio of </em><em>1.</em><em>00:1.93. The highest average survival rate of larvae in umbo-veliger and spat stages were 13.10</em><em>%</em><em> and 2.60%, respectively. The effect of protease enzyme activity on calcium carbonate production to produce oyster shell are also discussed in this paper.</em></p><p><em> </em><strong><em>Keywords</em></strong><em>:  water level pressure, protease enzyme activity, survival rate, growth, larvae, P. maxima</em></p>


Author(s):  
Nuraiffa Syazwi Adzami ◽  
◽  
Miskiah Fadzilah Ghazali ◽  
Amira Hidayati Ramli ◽  
Husnul Azan Tajarudin ◽  
...  

2018 ◽  
Vol 69 (5) ◽  
pp. 1272-1275 ◽  
Author(s):  
Camelia Tecu ◽  
Aurora Antoniac ◽  
Gultekin Goller ◽  
Mustafa Guven Gok ◽  
Marius Manole ◽  
...  

Bone reconstruction is a complex process which involves an osteoconductive matrix, osteoinductive signaling, osteogenic cells, vascularization and mechanical stability. Lately, to improve the healing of the bone defects and to accelerate the bone fusion and bone augmentation, bioceramic composite materials have been used as bone substitutes in the field of orthopedics and dentistry, as well as in cosmetic surgery. Of all types of bioceramics, the most used is hydroxyapatite, because of its similar properties to those of the human bone and better mechanical properties compared to b-tricalcium phosphate [1]. Currently, the most used raw materials sources for obtaining the hydroxyapatite are: bovine bone, seashells, corals, oyster shell, eggshells and human teeth. There are two common ways to obtain hydroxyapatite: synthetically and naturally. Generally, for the improvement of the mechanical properties and the structural one, hydroxyapatite is subjected to the sintering process. Considering the disadvantages of hydroxyapatite such as poor biodegradation rate, b-TCP has been developed, which has some disadvantages too, such as brittleness. For this reason, the aim of this study is to look into the effect of adding magnesium oxide on the sintering behavior, the structure and the mechanical properties of the hydroxyapatite-tricalcium phosphate composites.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hayer ◽  
Dirk Brandis ◽  
Alexander Immel ◽  
Julian Susat ◽  
Montserrat Torres-Oliva ◽  
...  

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.


2021 ◽  
Author(s):  
Hong Huang ◽  
Remzi Can Samsun ◽  
Ralf Peters ◽  
Detlef Stolten

Techno-economic performances of four different dimethyl carbonate production pathways are analysed based on the Power-to-Fuel concept.


2021 ◽  
pp. 105322
Author(s):  
Chin Soon Lionel Ng ◽  
Yong Kit Samuel Chan ◽  
Nhung Thi Hong Nguyen ◽  
Yuichi Preslie Kikuzawa ◽  
Shu Qin Sam ◽  
...  

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