Search results for "abrasion"
showing 10 items of 50 documents
Release of copper-amended particles from micronized copper-pressure-treated wood during mechanical abrasion
2016
Background We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. Results Our results indicate that the abrasion of MCA-pressure-treated wood does not cause an additional release of nanoparticles from the unreacted copper (Cu) carbonate nanoparticles from of the MCA formulation. Howev…
Reactive Powder Concrete Containing Basalt Fibers: Strength, Abrasion and Porosity
2020
The paper presents the test results of basalt fiber impact on a compressive and flexural strength, resistance to abrasion and porosity of Reactive Powder Concrete (RPC). The reasons for testing were interesting mechanical properties of basalt fibers, the significant tensile strength and flexural strength, and in particular the resistance to high temperatures, as well as a relatively small number of RPC tests performed with those fibers and different opinions regarding the impact of those fibers on concrete strength. The composition of the concrete mix was optimized to obtain the highest packing density of particles in the composite, based on the optimum particle size distribution curve acc.…
Retention strength of ball-attachment titanium post for removable partial denture or overdenture
2020
Aim: To evaluate the retention of an endodontic titanium post with a spherical head for removable partial denture or overdenture attachment according to surface treatment type. Methods: Sixty healthy single-rooted teeth, sectioned at the enamel/cementum junction, were treated endodontically and steadily fixed in the embedding acrylic resin. The titanium posts were subdivided into four groups: control, no surface treatment (Ctrl); posts with macro-retentive grooves (MR); air abrasion of the post surface (AB); and posts with macro-retentive grooves and air abrasion of the post surface (MR+AB). The posts were luted in the root canal using self-adhesive dual resin cement. Pull-out testing was p…
Physical pre-treatment of plums (Prunus domestica). Part 1. Modelling the kinetics of drying
2002
An alternative physical method for enhancing the drying rate of plums is proposed. It consists of the superficial abrasion of the plums' peel using an inert abrasive material to remove the cuticular waxy layer, the limiting factor for moisture loss. The physical pre-treatment was compared with a chemical treatment in which the plums were dipped into a solution of ethyl oleate. The drying kinetics of the above samples, including the untreated one, were reconstructed by using a mathematical model. The drying process, carried out at 60 C to reduce the prunes' quality loss, showed the great capability of both pre-treatments to enhance water diffusivity in the plum peel with respect to the untre…
Acne vulgaris and the most popular and new cosmetological treatments
2023
Introduction: Acne vulgaris is a disease that has an enormous impact on appearance of the skin of the patients and also on their quality of life. Long-term dermatological treatment, which often lasts years, and disease relapses contribute to the occurrence of low self-esteem and depression. Acne is one of the 10 most common diseases in the world and the most common inflammatory skin disease. Many methods of dermatological treatment that bring very good results are available. However, educating people with acne on how to take care of their skin on a daily basis to minimize the bleak effects of the disease is an extremely important element. Contemporary cosmetology creates an environment for …
Tool Wear and Damage
2008
This chapter provides comprehensive knowledge regarding tool wear mechanisms and characterizes their physical fundamentals. Adhesion, abrasion, diffusion and oxidation are selected as predominant mechanisms controlling tool wear, depending on the mechanical and thermal conditions at the rake and flank faces. The analytical models describing the wear rate and volumetric material loss for different wear mechanisms are provided. The tool wear indicators related to crater, flank and notch wear specified in ISO 3685 are presented for both flat-faced and grooved tools. Tool life is defined and corresponding models, including the influence of cutting speed, feed and the depth of cut, are derived. …
A new 3-d approach to determine functional morphology of cercopithecoid molars.
2005
Summary Functional relationships between diet and tooth morphology form an integral part of primatological and paleontological research. Previously, mostly two-dimensional parameters have been used to compare and interpret the complex crown morphology of cercopithecine and colobine molars. However, as teeth are three-dimensional objects, any dimensional reduction in describing their morphology must result in loss of information. In the current study we use a high resolution optical topometric system to record crown morphology in different wear stages in order to extract three-dimensional (3-d) parameters from virtual 3-d models. Structural parameters such as relief index, occlusal surface a…
Effects Of COOH-terminal tripeptide alpha-MSH (11-13) on corneal epithelial wound healing:role of nitric oxide
2006
It is known that alpha-melanocyte stimulating hormone (alpha-MSH) may exert anti-inflammatory effects and facilitate reparative processes in different tissues. The effective message sequence of alpha-MSH resides in the COOH-terminal tripeptide alpha-MSH(11-13). This study was undertaken to investigate the effects of topical administration of the COOH-terminal tripeptide sequence of alpha-MSH (alpha-MSH(11-13), KPV) on corneal epithelial wound healing in rabbits and the possible role of nitric oxide (NO) in these effects. The whole corneal epithelium was denuded in both eyes by mechanical abrasion. The area of the corneal epithelial defect was stained with fluorescein, photographed, and then…
A Split Face Comparative Study to Evaluate the Efficacy of 40% Pyruvic Acid vs. Microdermabrasion with 40% Pyruvic Acid on Biomechanical Skin Paramet…
2022
The synergy of cosmetic acids, with their keratolytic and antibacterial properties, with the mechanical exfoliation of the epidermis brings faster and better treatment results. The aim of the study was to compare the effects of using only pyruvic acid and the synergy of microdermabrasion and chemical exfoliation. In total, 14 women diagnosed with acne took part in the study. Two areas were marked on the participants’ faces: the right side (microdermabrasion treatment and a preparation containing pyruvic acid 40%) and the left side (preparation containing pyruvic acid 40%) without mechanical exfoliation. A series of four treatments was performed at 2-week intervals. Skin parameters such as s…