scholarly journals CLINICAL AND LABORATORY TESTING OF A NEW MODIFICATION OF TWO-LAYER "SILEP" DENTURES USED IN PROSTHETIC DENTISTRY

2020 ◽  
Vol 28 (28) ◽  
pp. 53-62
Author(s):  
Anton TIMOSHIN ◽  
Nikolay MITIN ◽  
Alexander OLEYNIKOV ◽  
Maria TIMOSHINA ◽  
Evgeniya MITINA
Keyword(s):  
Tensile Strength ◽  
Laboratory Testing ◽  
Polymer Materials ◽  
Shore Hardness ◽  
Physical Strength ◽  
Suitable Material ◽  
Removable Prosthesis ◽  
First Time ◽  
Compound Materials ◽  
The Ideal

Dentistry is a part of medicine, where various polymer materials were used for the first time. Many factors forced researchers to find more stable, versatile, and hygienic materials for the manufacture of dental products. It is important to note that the search for the ideal polymer dental material is still ongoing. This is because modern polymers, in some cases, do not meet the specified requirements for chemical, physical, strength, and elastic properties. Based on the data on the method of creating and using silicone material for the base of the removable prosthesis "Gossil", an improved silicone material for two-layer dentures "Silep" was developed, as well as a special primer for better connection of the lining with the rigid acrylic base of the prosthesis. To evaluate the most suitable compound, materials were tested for several parameters, such as tensile strength, elongation, and shore hardness. In addition to selecting a suitable material for modification, the selection and testing of an adhesive that allows the chemical bonding of the acrylate surface to the siloxane surface were carried out.

scholarly journals Clinical and Laboratory Testing of a New Modification of Two-Layer "Silep" Dentures Used in Prosthetic Dentistry

2020 ◽  
Vol 28 (28) ◽  
pp. 53-62
Author(s):  
Anton Timoshin ◽  
Nikolay Mitin ◽  
Alexander Oleynikov ◽  
Maria Timoshina ◽  
Evgeniya Mitina
Keyword(s):  
Tensile Strength ◽  
Laboratory Testing ◽  
Polymer Materials ◽  
Shore Hardness ◽  
Physical Strength ◽  
Suitable Material ◽  
Removable Prosthesis ◽  
First Time ◽  
Compound Materials ◽  
The Ideal

Dentistry is a part of medicine, where various polymer materials were used for the first time. Many factors forced researchers to find more stable, versatile, and hygienic materials for the manufacture of dental products. It is important to note that the search for the ideal polymer dental material is still ongoing. This is because modern polymers, in some cases, do not meet the specified requirements for chemical, physical, strength, and elastic properties. Based on the data on the method of creating and using silicone material for the base of the removable prosthesis "Gossil", an improved silicone material for two-layer dentures "Silep" was developed, as well as a special primer for better connection of the lining with the rigid acrylic base of the prosthesis. To evaluate the most suitable compound, materials were tested for several parameters, such as tensile strength, elongation, and shore hardness. In addition to selecting a suitable material for modification, the selection and testing of an adhesive that allows the chemical bonding of the acrylate surface to the siloxane surface were carried out

The Republic

2019 ◽  
pp. 205-229
Author(s):  
Dominic Scott
Keyword(s):  
Political Theory ◽  
Left Behind ◽  
Ideal State ◽  
The Republic ◽  
Individual Justice ◽  
The Individual ◽  
Political Right ◽  
First Time ◽  
The Ideal

This chapter presents a reading of Plato’s Republic. The Republic is among Plato’s most complex works. From its title, the first-time reader will expect a dialogue about political theory, yet the work starts from the perspective of the individual, coming to focus on the question of how, if at all, justice contributes to an agent’s happiness. Only after this question has been fully set out does the work evolve into an investigation of politics—of the ideal state and of the institutions that sustain it, especially those having to do with education. But the interest in individual justice and happiness is never left behind. Rather, the work weaves in and out of the two perspectives, individual and political, right through to its conclusion. All this may leave one wondering about the unity of the work. The chapter shows that, despite the enormous range of topics discussed, the Republic fits together as a coherent whole.

scholarly journals Laboratory Study of Deformation Behaviour of Two New Reinforcing Polymeric TSLs and Their Potential Application in Deep Underground Coal Mine

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2205
Author(s):  
Han Liang ◽  
Jun Han ◽  
Chen Cao ◽  
Shuangwen Ma
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Underground Mining ◽  
Deformation Behaviour ◽  
Polymer Materials ◽  
Surface Protection ◽  
Steel Mesh ◽  
Geological Conditions ◽  
Deep Underground ◽  
Roadway Support

Thin spray-on liner (TSL) is a surface protection technology used by spraying a polymer film, which is widely used for mine airtightness and waterproofing. A reinforcing TSL can replace steel mesh, which is a new method for roadway support. This paper reviews the development of a reinforcing TSL. Considering the deterioration of geological conditions in deep underground mining and the demand for reinforcing automation, two kinds of polymeric reinforcing TSL (RPTSL) materials are developed. The mechanical characteristics of the new TSL materials are studied experimentally. Results show that the average compressive strength, tensile strength, cohesion, and internal friction angle of the two TSL materials are 52 and 32 MPa, 12 and 8 MPa, 6.2 and 17.2 MPa, and 33.6° and 25.9°, respectively. The bonding strength between the two materials and coal is greater than the tensile strength of coal itself, and the mechanical properties of the material for comparison are lower than those of both materials. Based on the TSL support mechanism, we examine the application of the two TSL materials to the mining environment and compare the mechanical properties of polymer materials and cement-based materials. The advantages of polymer materials include versatile mechanical properties, good adhesion, and high early strength. This study provides a new support material to replace steel mesh for roadway surface support, which satisfies the needs of different surface support designs under complex geological conditions, and promotes the automation of roadway support.

Philosophy and Education

1998 ◽  
pp. 32-36
Author(s):  
Luciana Bellatalla
Keyword(s):  
Western Culture ◽  
Cultural Tradition ◽  
The World ◽  
Dialogic Approach ◽  
First Time ◽  
The Ideal

From its first appearance in western culture, philosophy has been considered able to build up reality, to educate people, and to disclose truth. Plato proposed philosophers as governors in life-long pursuit of philosophical learning. Socrates was the ideal paradigm of an educating philosopher: he tried to wake up human minds so that they could be aware of themselves and of the world, criticizing tradition and prejudices in a logically consistent perspective. A critical and dialogic approach—not by mere chance defined as "Socratic"—to problems has been considered until now the most profitable method of teaching. Socrates is a pioneer in discussing the question of a philosophical (paideia), as he defined his method "maieutic." He was not an authoritarian teacher, but a sparring partner in the process of self-education. Moreover, he considered himself as the most learned and, at the same time, the wisest in Greece, just because he was conscious of his ignorance. Therefore, he understood for the first time in our cultural tradition that knowledge is an endless process rather than a product, within marked bounds.

scholarly journals Composites from Thermoplastic Natural Rubber Reinforced Rubberwood Sawdust: Effects of Sawdust Size and Content on Thermal, Physical, and Mechanical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
High Density Polyethylene ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Shore Hardness ◽  
Thermoplastic Natural Rubber ◽  
Plastic Content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.

Anab initiocalculation of the ideal tensile strength of β-silicon nitride

2001 ◽  
Vol 64 (17) ◽  
Author(s):  
Shigenobu Ogata ◽  
Naoto Hirosaki ◽  
Cenk Kocer ◽  
Hiroshi Kitagawa
Keyword(s):  
Tensile Strength ◽  
Silicon Nitride ◽  
The Ideal

The Activities of the Tube Feet of Asterias Rubens L

1947 ◽  
Vol s3-88 (1) ◽  
pp. 1-14
Author(s):  
J. E. SMITH
Keyword(s):  
Forward Direction ◽  
The Other ◽  
Asterias Rubens ◽  
Ideal Form ◽  
First Time ◽  
Intrinsic Musculature ◽  
Tube Feet ◽  
Postural Muscles ◽  
The Ideal

1. An account is given of the muscular anatomy of the foot and ampulla of Asterias rubens. An intrinsic musculature of the sucker figured by Cuénot (1891) and Chadwick (1923) is shown not to be present; on the other hand, postural muscles responsible for orientating the podium, levator fibres which ‘cup’ the sucker, and radial fibres which flatten it are described and figured for the first time. 2. The role of the different muscle systems, the collagen connective tissue, and the fluid of the hydrocoel in protracting and retracting the foot, and in effecting the attachment and detachment of the sucker, is discussed. 3. Evidence is presented, to show that postural pointing of the foot is brought about by the contraction of a ring of muscles encircling the base of the podium. The orienting muscles are functionally, but not anatomically, distinct from the longitudinal fibres of the retractor sheath. 4. The ambulatory step is shown to comprise a series of linked phases of static posture and of movement. Each phase is characterized by the contraction of one member of each of the two opposing pairs of muscles engaged in the development of the step. The two pairs of muscles are (1) the anterior and posterior orienting fibres, and (2) the protractors and retractors of the foot. In its ideal form the step comprises four phases of static posture alternating with four movements. Each movement is ushered in by a reversal of the contraction-relaxation relationships of one of the two pairs of opposing muscle systems. Four such changes are possible and they occur in a sequence that ensures the orderly succession of the four movements of protraction, swing back, retraction, and swing forward, of which movements the idealized stepping cycle is composed. 5. The actual locomotory step departs from the ideal form in two respects: (1) it is liable to become disrupted by a delay in the initiation of the protraction or of the backswing movement, and (2) withdrawal of the podium occurs simultaneously with its re-orientation in the forward direction. It is pointed out that these variations are explicable on the assumption that, in the two series of opposing muscle pairs, the retractor fibres are more readily excited to contract than are their antagonists, and the anterior postural muscles than the posterior postural fibres.

Franciscan Books and their Readers

2022 ◽  
Author(s):  
René Hernández
Keyword(s):  
Space Form ◽  
Northern Italy ◽  
Ideal Space ◽  
Skilled Readers ◽  
Personal Library ◽  
Key Aspects ◽  
Cultural Agency ◽  
First Time ◽  
The Ideal

The book explores the manuscripts written, read, and studied by Franciscan friars from the thirteenth to the fifteenth centuries in Northern Italy, and specifically Padua, assessing four key aspects: ideal, space, form and readership. The ideal is studied through the regulations that determined what manuscripts should aim for. Space refers to the development and role of Franciscan libraries. The form is revealed by the assessment of the physical configuration of a set of representative manuscripts read, written, and manufactured by the friars. Finally, the study of the readership shows how Franciscans were skilled readers who employed certain forms of the manuscript as a portable, personal library, and as a tool for learning and pastoral care. By comparing the book collections of Padua’s reformed and unreformed medieval Franciscan libraries for the first time, this study reveals new features of the ground-breaking cultural agency of medieval friars.

scholarly journals The Influence of Manufacturing Parameters on the Mechanical Behaviour of PLA and ABS Pieces Manufactured by FDM: A Comparative Analysis

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1333 ◽  
Author(s):  
Adrián Rodríguez-Panes ◽  
Juan Claver ◽  
Ana Camacho
Keyword(s):  
Tensile Strength ◽  
Mechanical Behaviour ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Polymer Materials ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Layer Orientation ◽  
Lower Variability

This paper presents a comparative study of the tensile mechanical behaviour of pieces produced using the Fused Deposition Modelling (FDM) additive manufacturing technique with respect to the two types of thermoplastic material most widely used in this technique: polylactide (PLA) and acrylonitrile butadiene styrene (ABS). The aim of this study is to compare the effect of layer height, infill density, and layer orientation on the mechanical performance of PLA and ABS test specimens. The variables under study here are tensile yield stress, tensile strength, nominal strain at break, and modulus of elasticity. The results obtained with ABS show a lower variability than those obtained with PLA. In general, the infill percentage is the manufacturing parameter of greatest influence on the results, although the effect is more noticeable in PLA than in ABS. The test specimens manufactured using PLA perform more rigidly and they are found to have greater tensile strength than ABS. The bond between layers in PLA turns out to be extremely strong and is, therefore, highly suitable for use in additive technologies. The methodology proposed is a reference of interest in studies involving the determination of mechanical properties of polymer materials manufactured using these technologies.

scholarly journals Self-Dividing Micelles: A Mechanistic Look with Evolutionary and Clinical Implications

2021 ◽  
pp. 8-20
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Laboratory Testing ◽  
Prebiotic Chemistry ◽  
Clinical Implications ◽  
Proof Of Concept ◽  
Mass Spec ◽  
First Time ◽  
Division Mechanism ◽  
Viable Treatment

Micellar therapy has become a usefully viable treatment arm in various fields, ranging from oncology to bioimaging. As such, research leading to any improvements or adaptations in administration and techniques can have far-reaching consequences. Potential aspects of prebiotic chemistry may also be explored in such research as well. To that end, proof-of-concept experiments were performed to elucidate a possible mechanism of action for prebiotic protocell division. Representative potentially prebiotically plausible biomolecules, i.e., a fatty acid, amino acid, and nucleotide were mixed and heated in water and subjected to microscopic examination for observation of possible self-division and laboratory testing for the presence of polypeptides and polynucleotides (Biuret, MALDI mass-spec, etc.) with and without the presence of nucleotide. The results are presented for the first time here and a mechanism is proposed that best fits the data obtained. The evolutionary, e.g., prebiotic biomolecular cooperativity, and clinical, e.g., potential antineoplastic micellar/vesicular therapy, ramifications are discussed as well. Keywords: Micelle; Liposome; Protocell; MRNA; Self-division; Mechanism; Solid tumors

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