نتایج جستجو برای: pumice powder
تعداد نتایج: 47653 فیلتر نتایج به سال:
BACKGROUND A prolonged life of fissure sealant has always been the target for preventing caries in vulnerable newly erupted teeth. The use of preparatory techniques including bur introduction to the fissures is considered among such improving steps. MATERIALS AND METHODS Ninety freshly extracted healthy maxillary premolar teeth were randomly selected for this investigation. Teeth were then di...
This paper presents and discusses the Neutron Activation Analysis (NAA) results newly obtained from pumice pieces found decades ago at the Egyptian sites of Maiyana, Sedment, Kahun, and Amarna – now in the collections of the Ashmolean Museum, Oxford, and the Petrie Museum of Egyptian Archaeology, London – which could be successfully related to several volcanic eruptions in the Mediterranean. Th...
Silicic tuffs infilling an ancient submarine caldera, at Mineral King in California, show microscopic fabrics indicative of welding of glass shards and pumice at temperatures >500 degrees C. The occurrence indicates that subaqueous explosive eruption and emplacement of pyroclastic materials can occur without substantial admixture of the ambient water, which would cause chilling. Intracaldera pr...
PURPOSE The aim of this study was to determine the effect of the acquired pellicle on enamel etching. MATERIALS AND METHODS One-hundred teeth were sectioned in the buccal-lingual direction at the half crown. One-hundred half-crowns were polished with pumice powder and rotating brushes (group B) and one-hundred half-crowns were not polished on the buccal surface (group A). The samples were etc...
background: in recent years, proficient treatment of wastewaters containing recalcitrant and toxic compounds such as phenol has been a challenge. this study introduced and evaluated an efficient option for treating such wastewater . methods: this experimental study was performed on phenol removal as a recalcitrant and toxic compound in aqueous solutions in 2011. the pumice stone was collected f...
Influence of polishing methods on water sorption and solubility of denture base acrylic resins was studied. Eighty samples were divided into groups: Classico (CL), and QC 20 (QC) - hot water bath cured; Acron MC (AC), and Onda Cryl (ON) - microwave cured; and submitted to mechanical polishing (MP) - pumice slurry, chalk powder, soft brush and felt cone in a bench vise; or chemical polishing (CP...
BACKGROUND We evaluated the Bovine hydroxyapatite (BHA) structure. BHA powder was admixed with 5 and 10 wt% natural pumice (NP). Compression strength, Vickers micro hardness, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction studies were performed on the final NP-BHA composite products. The cells proliferation was investigated by MTT assay and SEM...
In order to study the effects of pumice (control, 30 and 60 ton ha-1) and different concentrations of Acadian and Estemplex (algae extract) (0, 1.5, 3 and 4.5 ml L-1) on the growth and some physiological characteristics of Coriandrum sativum L., an experiment was conducted as factorial based on a randomized complete block design with three replications at Azarbaijan’s Shahid Madani University, ...
Concrete's drawback is its low tensile strength and heavy weight, which may exceed 2400 kg/m3. The significance of self-weight in building construction essential, particularly when dealing with seismic loads. larger the inertial force from weight structure itself, greater therefore lightweight concrete can provide an opportunity to lower own a smaller unit 1850 Fly ash was employed as substitut...
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