263 research outputs found
Two kinds of procedural semantics for privative modification
In this paper we present two kinds of procedural semantics for privative modification. We do this for three reasons. The first reason is to launch a tough test case to gauge the degree of substantial agreement between a constructivist and a realist interpretation of procedural semantics; the second is to extend Martin-L ̈f’s Constructive Type Theory to privative modification, which is characteristic of natural language; the third reason is to sketch a positive characterization of privation
PREDICATION AND EXTENSIONALIZATION
In his 2000 book Logical Properties Colin McGinn argues that predicates denote properties rather than sets or individuals. I support the thesis, but show that it is vulnerable to a type-incongruity objection, if properties are (modelled as) functions, unless a device for extensionalizing properties is added. Alternatively, properties may be construed as primitive intensional entities, as in George Bealer. However, I object to Bealer’s construal of predication as a primitive operation inputting two primitive entities and outputting a third primitive entity. Instead I recommend we follow Pavel Tichý in construing both predication and extensionalization as instances of the primitive operation of functional application.PhilosophyTechnology, Policy and Managemen
Morphogenesis of Palatal Ridges in the Golden Hamster (Mesocricetus auratus, Rodentia)
Effect of rubber powder from waste tyre rubbers on mechanical properties of one-component polyurethane putty
ArticleThe utilization of adhesives in technical practice is varied. Adhesives serve for a
creation of strength bonds on the one hand, and on the other hand e.g. for cementing. The aim of
the research is a modification of one
-
component polyurethane putty RPS 45 used in automotive
industry to increase strength properties in an adhesive bond. An i
nteraction between a filler in the
form of rubber powder micro
-
particles and one
-
component polyurethane adhesive was
investigated by means of SEM analysis. Sealing is a primary property of this putty. Sealing putties
usually reach very small strength which
can be increased by an admixture of the filler. In order
to keep elastic properties, micro
-
particles of the rubber powder gained from tyre recycling process
were used as the filler. An aspect of a loading speed of the adhesive bond is essential at the
pra
ctical application at which the adhesive bond can be failed in adhesive or cohesive layers. The
adhesive bond can be perceived in terms of its function as a complex of three layers, i.e. an
adhesive bonded material, the interaction between the adhesive and
the adhesive bonded material
and the adhesive layer itself. There are often states in the practices when the adhesive bonds are
exposed to the loading which can be either a static or a dynamic one. That is why the research is
focused not only on the evalu
ation of the influence of the modification of the one
-
component
polyurethane adhesive, but also on the influence of the loading speed of the adhesive bond. Tested
speeds set on a universal testing machine Zwick/Roell Z150 were 2, 50 and 100
mm
min
-
1
. The
r
esults of mechanical tests proved a positive influence of the filler on the strength σ
m
higher by
42.68
±
6.96% and the elongation at break ε
b
higher by 12.2
±
20.95%. On the contrary, the stress
at yield σ
y
was decreased
Research on influence of cyclic degradation process on changes of structural adhesive bonds mechanical properties
ArticleThe paper deals with an influence of a cyclic degradation process on changes of a shear
tensile strength of single lap-shear adhesive bonds and their elongation according to ČSN EN
ISO 9142. Five one-component structural adhesives used in a construction of car body works
were used within the research. The degradation of adhesive bonds is a significant factor which
influences a quality and a service life of adhesive bonds exposed to environment. A main
requirement in production companies is not only reaching satisfactory initial mechanical
properties but namely ensuring a reliability and a safety of adhesive bonds during their usage.
These reasons show a great importance of adhesive bonds tests either directly in the operating
environment or by a simulation of operating conditions in laboratories. The degradation process
of adhesive bonds worsens mechanical properties of not only the bond itself but also of the bonded
material. This process is progressing and it is usually permanent and irreversible. It is a change
of mechanical and physical properties which can endanger a safety and a reliability of parts,
prospectively of the whole equipment. It can leads up to a complete failure of its function in the
extreme case. A temperature, a moisture, a direct contact with water and chemicals or an
atmospheric corrosion belong among the most serious degradation agents. It is important to take
into regard time of the processes influence at the same time which can act either independently
or concurrently when their effects grow stronger.
From that reason the adhesive bonds were exposed to the cyclic degradation process according
to the standard ČSN EN ISO 9142. Subsequently, the adhesive bonds mechanical properties were
tested on universal testing machine and by means of SEM analysis (TESCAN MIRA 3).
Results of mechanical tests proved a fall of the shear tensile strength of single lap-shear adhesive
bonds after 42 cycles of the degradation process of 12.8 to 21.7%. The bond strength fall was
gradual and it showed a linear trend at some adhesives. Other adhesives showed a significant fall
after the exposition to the degradation process after which the strength fall stabilized
Reliability of Human Subject - Artificial System Interactions
Main problems related to reliability of interaction between human subject and artificial system (namely of the transportation character) are discussed. The paper consists of three mayor parts:The first one is devoted to the theoretical backgrounds of the problem from the both theory of system reliability and neurology/psychology views.Second part presents the discussion of relevant methodologies of the classification and prediction of the reliability decline. The methodology based on EEG pattern analysis is chosen as the appropriate one for the presented task. The key phenomenon of "micro-sleep" is discussed in detail.The last part presents some latest experimental results in context of presented knowledge. Proposals for the future studies are presented at the end of the presented article. The special interest should be devoted to the analysis and in-time prediction of fatal attention decreases and to the design and construction of the respective on-board applicable warning system
Preliminary measurements of lumbar spine kinematics and stiffness
The purpose of the presented study was the experimental measurement of lumbar spine stiffness and its range of motion. The dependence of torsion moment of lumbar spine segment on deflection of flexion, extension and torsion was observed during experiments. Stiffness of spine segment was determined from measured data. Human lumbar spine was used for verification of the experimental technique. The sample consisted of one lumbar vertebrae composed by five vertebral bodies and four intervertebral discs. All muscles were removed, however all ligaments were preserved. Experiments were ca rried out on the test system MTS 858.2 MiniBionix, where loading by axial force and torsion moment is possible at the same time. Special Modular Bionix Spine Test Fixator, attached to the test system was used for the measurements. Loading was controlled kinematically (gradual turning) by keeping the axial force equal zero. Measurement was timedependent. The results of these experiments are going to be used as input data for creating a model of artificial lumbar spine and new type of artificial disc replacement
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