Relationship between ae signal strength and absolute energy in determining damage classification of concrete structures

The most efficient tools in real monitoring system is acoustic emission (AE). This technique can be used to identify the damage classifications in RC structure. This research paper will mainly focus on the utilization of signal strength and Absolute energy (AE signal) in determining on the damage quantification for RC beam subjected to cyclic load test. The beam specimens size (150 X 250 X 1900) mm were prepared in the laboratory and tested with the four point bending test using cyclic loading together with acoustic emission monitoring system. The results showed that the analysis of AE data parameters is capable of determining the damage classification in concrete structures and the data corresponded to the visual observations during the increased loading cycle

The Effectiveness of Wedge-Shaped Dental Defects with the Combined Use of Hydroxyapatite and Fluoride-Containing Drugs and Measures for Their Prevention In Undergrowth

Currently, there is a significant increase in the prevalence of non-carious lesions of the teeth, leading to a significant loss of enamel and dentin, hypersensitivity and aesthetic defect. The most common type of non-carious pathology is CDZ, which makes up 37.5%[2.4]. The structure of non-carious lesions of the teeth is getting younger every year. So today, CDZ occur at the age of 20 years, and sometimes in adolescents. Previously, it was believed that this is pathology of people over forty years old [1.3]

Comparative study of coral conversion, Part 2: Microstructural evolution of calcium phosphate

© 2015, The Australian Ceramic Society. Calcium phosphate materials can be easily produced by a number of wet chemical methods that involve both acidic and basic environments. In our previous study, we investigated calcium phosphates such as monetite (DCPA), hydroxyapatite (HAp) and whitlockite which were successfully produced by mechano-chemical method from corals obtained from the Great Barrier Reef. It was observed that a number of synthesis factors such as the pH of the environment, the reaction temperature and the chemistry influenced the crystal size formed. A number of theories have been suggested on the mechanisms of crystal formation; however, very few mechanisms have been universally accepted. The present work was aimed to explore the evolution of crystalline calcium phosphate and their morphology with respect to the pH of the environment and reaction time. Conversion of coral to calcium phosphates was carried out with stoichiometric amount of required H3PO4 or (NH4)2HPO4, to obtain hydroxyapatite or tricalcium phosphate (TCP) phases. The acidic or basic solution was added, drop wise, at a rate of 2 mL min-1, to 6 g of coral powder suspended in 300 mL of distilled water at 80 ± 0.5°C on a hot plate with magnetic stirrer. The pH of reaction was monitored. Crystal morphology and the phases were identified by XRD, FTIR, and SEM studies. It was observed that under acidic conditions (H3PO4), dissolution and then precipitation influences the crystal morphology and transition from plate like to rod like hydroxyapatite structure. During the first hour of the dissolution a monetite and hydroxyapatite mixture precipitates and then the full conversion to hydroxyapatite is observed. However under basic conditions (NH4)2HPO4), pH is only marginally changed within the environment and just surface conversion of the calcium carbonate structure of coral to hydroxyapatite and a very small amount of tri-calcium phosphate is observed. The mechanism can be classified as the solid state topotactic ion-exchange reaction mechanism

PENAMBAHAN SERBUK OLAHAN DARI GIGI SAPI TERHADAP SIFAT MEKANIK DAN FISIK MODEL GIGI TIRUAN

Abstrak: Penambahan serbuk olahan dari gigi sapi terhadap sifat mekanik dan fisik model gigi tiruan. Tujuan dari penelitian ini adalah mendapatkan HA dari gigi sapi sebagai bahan pengganti bahan baku impor. Limbah gigi sapi disintesis menjadi bubuk HA, dan selanjutnya dikarakterisasi dengan SEM dan EDX untuk mengetahui struktur mikro dan komposisi kimia serbuk. Geligi sapi ini dilepaskan dari rahang, dicuci dan kemudian direbus dalam air mendidih selama 3 jam dengan presto untuk menghilangkan sumsum tulang dan lemak yang melekat. Gigi selajutnya dicacah, digiling dan dihaluskan dengan ball mill sebelum dikalsinasi beberapa kali pada temperatur 800oC. Hasil penelitian menunjukkan bahwa pengolahan gigi sapi relatif lebih sulit dari pada tulang sapi. Kalsinasi selama 3 kali sudah meningkatkan kandungan Kalsium dan Posfor menjadi sekitar 33% dan 16% pada sampel serbuk, namun kadar ini dinilai masih jauh lebih rendah dari potensi sebenarnya. Oleh sebab itu, beberapa tahapan proses masih berlanjut untuk menghasilkan serbuk yang superhalus dengan karakteristik fisik menyamai serbuk impor. Kemudian dilakukan pembuatan model gigi tiruan dengan mencampurkan serbuk HA dari gigi sapi dan resin dilanjukan pengujian struktur mikro, pengujian kekerasan dan uji tekan. Nilai kekerasan sampel gigi tiruan 40,3 VHN dan kekuatan tekan 45,4 MPa. Kata Kunci : Gigi tiruan, resin, gigi sapi, Hydroxypatite (HA), Ball mill. Kekerasan, Kekuatan tekan

Levantamento do seio maxilar pela técnica da janela lateral: tipos enxertos

ResumoO objetivo principal desta revisão bibliográfica é sistematizar e determinar qual omaterial de enxerto ósseo de eleição no levantamento do seio maxilar atrófico pela técnica da janelalateral para posterior colocação de implantes dentários (segunda fase cirúrgica) em função da alturaganha de osso. Como objetivo secundário, tentamos avaliar qual o efeito do uso dos promotores decrescimento, da mistura dos diversos biomateriais com osso autólogo e a sobrevivência dos implantesdentários nos diferentes tipos de enxertos. A pesquisa foi realizada na base de dados Pubmed, utilizando-se o total de 22 artigos datados de 2005a 2011. As exclusões deveram-se aos artigos referirem-se a colocação dos implantes dentários numaetapa, a técnica utilizada não ser a janela lateral ou inadequado desenho do estudo.AbstractThe main objective of this literature review was to try with a simple and systematic observer which was the bone graft material of choice in sinus lift of atrophic maxilla for the technic of lateral window, to placing dental implants (second surgical phase) in according the gain of bone height. As asecond objective we try to understand what is the effect of the use of growth romoters, the mixture of various biomaterials whith autologous bone and the survival of dental implants in different types of grafts. The research was conducted in Pubmed database, using a total of 22 articles dating from 2005 to 2011.The exclusions were due to articles refer to a one surgical phase, the technique used was not the lateral window or a inadequate study design

Sintesis dan Karakterisasi Struktur Padatan NiO/CaF2 dengan Difraksi Sinar-X

Sifat keasaman NiO dapat digunakan sebagai katalis dalam sintesis yang mengikuti reaksi Friedel-Crafts. Pada penelitian ini, telah dilakukan sintesis padatan CaF2 dan NiO/CaF2 padat dengan variasi loading Ni (2,5; 5,0; 7,5, 10 dan 15% w/w) dan karakterisasi struktur padatan menggunakan X-ray difraksi. Difraktogram CaF2 hasil sintesis menunjukkan puncak yang sesuai dengan data base JCPDS-Internasional Centres for Diffraction Data tahun 1997 dengan nomer PDF 35-0816. Difraktogram padatan impregnasi NiO/CaF2 hasil sintesis menunjukkan bahwa gabungan dari puncak NiO dan CaF2, semakin tinggi jumlah loading Ni intensitas puncak NiO semakin tinggi pula

Effect of the Mg/Al ratio and of the rate of reinforcement on the synthesis of a nanocomposite Cellulose/Hydrotalcite

The objective of this work is to synthesize a nonmaterial by introducing synthetic clay (hydrotalcite) as a nanofiller in a natural polymer matrix (cellulose) and to study the effect of Mg/Al ratio and the rates of reinforcement.Cellulose fibers were extracted from ‘Yucca‘ tree’s leaves by a chemical treatment and Hydrotalcite (MgAlCO3) was synthesized by the method of co-precipitation at fixed pH with a ratio of Mg/Al=2 or 3.The composite materials were elaborated by microwave activation.The Hydrotalcites with an Mg/Al ratio = 2 or 3 were tested as well as various rates of reinforcement (2, 5 or 10% Hydrotalcite) in order to optimize conditions of obtaining a nanomaterial. The structures of obtained materials were characterized by IR spectroscopy, X-ray Diffraction and Transmission Electron Microscopy. The thermal stability was analyzed by TG-DTA analyses.The characterizations carried out on these compounds revealed structural modifications in agreement with the formation of a nanomaterial (cellulose/Hydrotalcite) with the improved thermal properties