Mechanical Testing Following the Application of Polymers on Different Types of Screws Used to Fix Osteoporotic Bone

2021 ◽  
Author(s):  
Alexandru Filip ◽  
Mihaela Pertea ◽  
Dan Cristian Moraru ◽  
Bogdan Huzum ◽  
Claudiu Carp ◽  
...  
Keyword(s):  
Mechanical Testing ◽  
Osteoporotic Bone ◽  
Different Types

scholarly journals Morphological evaluation of the active tip of six types of orthodontic mini-implants

2013 ◽  
Vol 18 (2) ◽  
pp. 36-41 ◽  
Author(s):  
Flávia Mitiko Fernandes Kitahara-Céia ◽  
Tatiana Féres Assad-Loss ◽  
José Nelson Mucha ◽  
Carlos Nelson Elias
Keyword(s):  
Mechanical Testing ◽  
Optical Microscope ◽  
Internal Thread ◽  
Orthodontic Anchorage ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Mini Implants ◽  
Morphological Evaluation ◽  
Different Types ◽  
Different Characteristics

OBJECTIVE: To morphologically evaluate the active tip of six different types of self-drilling mini-implants for orthodontic anchorage. METHODS: Images of the active tips of the mini-implants were obtained with a Zeiss optical microscope, Stemi 200-C with magnification of 1.6X. The images of the surface were viewed with the Axio Vision program (Zeiss, Jena, Germany) to calculate linear and angular measures. Mini-implant morphology and the details of tips and threads were also evaluated through Scanning Electronic Microscopy (SEM) (JEOL, model JSM5800 LV - JEOL, Tokyo, Japan) with magnifications of 90X and 70X, respectively. The evaluation of the mini-implant taper shape was assessed using to the formula: (b - a) / (2 x D). RESULTS: The following variables were measured: (1) active tip width, (2) major diameter of external thread, (3) minor diameter of internal thread and taper of the mini-implant, (4) number of threads and lead of the screw, (5) angle of thread, (6) flank width and (7) pitch width. CONCLUSION: Mini-implants from different manufacturers presented active tips with different characteristics. Mechanical testing is necessary to cor-relate the analyzed characteristics aiming to determine the best performance.

Determination of Mastication Forces in Case of Total Dental Prosthesis

2015 ◽  
Vol 638 ◽  
pp. 145-150
Author(s):  
Lucian Rusu ◽  
Cosmina Vigaru ◽  
Dan Ioan Stoia
Keyword(s):  
Mechanical Testing ◽  
Dental Implant ◽  
Dental Prosthesis ◽  
The Body ◽  
Testing Equipment ◽  
Space Distribution ◽  
Vertical Force ◽  
Complicated Process ◽  
Different Types

In whole wide world, lots of individuals lose teeth from different causes. In these cases, in first phase, a dental implant is the best solution. In some cases, as the last solution, a dental prosthesis is needed. To correct these disorders, rehabilitation treatments with adequate dentures, either fixed or removable, are indicated. [6] The forces that appear during mastication are influenced by occlusion type and space distribution of teeth. In case of persons that have a dental prosthesis the forces that occurred during mastication can be reduced if the dental prosthesis is correctly generated. A mastication simulator is any device that reproduces the conditions present during the process of chewing in order to reconstruct the complicated process of mastication outside the body. [5] The aim of this paper is to produce a device that can simulate the mastication and use it to determinate the mastication forces that appears during the mastication of different foods types. On the device that was build can be placed different dental prosthesis. [2] Using the device adjustment facilities we are able to simulate any type of occlusion. Using this device, a mechanical testing equipment and different types of food we are able to determinate the vertical force that occur. Base on these results we will be able to determinate if the dental prosthesis was correctly produced.

The Evaluation of Different Types of Welding in the Orthodontic Expanders

2015 ◽  
Vol 1111 ◽  
pp. 56-61
Author(s):  
Camelia Szuhanek ◽  
Traian Fleșer
Keyword(s):  
Laser Welding ◽  
Mechanical Testing ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Different Types ◽  
Laboratory Procedures ◽  
Physical And Chemical ◽  
And Chemical Properties

The purpose of our paper was to evaluate the effect of different methods of welding in the laboratory procedures of orthodontic expanders. The results of flame, ultrasound, resistance and laser welding methods were evaluated by means of mechanical testing. Metallographic investigations were also used in order to compare the results of different welding testing. A combination of techniques which offer optimum mechanical, biological, physical and chemical properties must be selected. New results are presented in comparison to previous research with published results.

Transform a Mechanical Testing Machine into High-Temperature Disk Spring Stress Relaxation Test Equipment

2014 ◽  
Vol 989-994 ◽  
pp. 3224-3227
Author(s):  
Xiao Yu Zhou ◽  
Yi Zhong Yu
Keyword(s):  
High Temperature ◽  
Stress Relaxation ◽  
Mechanical Testing ◽  
Testing Machine ◽  
High Sensitivity ◽  
Loss Ratio ◽  
Stress Relaxation Test ◽  
Disk Spring ◽  
Different Types ◽  
Failure Life

Prediction of disk spring failure life due to stress relaxation is necessary for users; the problem was not solved before. According to special test requirement, we modified a 100N mechanical testing machine into high temperature testing equipment which can be used for different types of disk spring. With a test for 36 days on a group of 45×22.5×3.5×2.5 mm disk springs, a result of prediction of 3.38% load loss ratio after 12 years relaxation is obtained, these disk springs are qualified. Our modified equipment has the advantages of real time, heavy loading, high sensitivity and good generality.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj> 0 for eachj> 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Differentiating between different forms of moral obligations

2020 ◽  
Vol 43 ◽  
Author(s):  
Rajen A. Anderson ◽  
Benjamin C. Ruisch ◽  
David A. Pizarro
Keyword(s):  
Moral Character ◽  
Moral Obligations ◽  
Different Types

Abstract We argue that Tomasello's account overlooks important psychological distinctions between how humans judge different types of moral obligations, such as prescriptive obligations (i.e., what one should do) and proscriptive obligations (i.e., what one should not do). Specifically, evaluating these different types of obligations rests on different psychological inputs and has distinct downstream consequences for judgments of moral character.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

Sign in / Sign up

Export Citation Format

Share Document