Diagrams and the Concept of Logical System

Author(s):  
Jon Barwise ◽  
Eric Hammer

In attempting to analyze the notion of a logical system, there are various approaches that could be taken. One would be to look at the things people have called logical systems and try to develop a natural framework which would encompass most or many of these, and then explore the consequences of the framework, seeing what else falls under the framework and what the consequences of the general notion happen to be. This was basically the approach taken, for example, in Barwise [1974], one of the early attempts to develop such a framework. This approach has much to recommend it, but it also has at least two serious drawbacks. It is too dependent on accidents of history, that is, on what particular systems of logic people happened to have developed. There is at least the theoretical possibility that biases of precedent and fashion have played a significant role in the way things have gone. If so, the abstraction away from practice has the danger of codifying these historicallycontingent biases, making them appear like necessary features of a logical system. The flip side of this problem is that there may well be some unnatural logical systems which contort the framework. But how else could one proceed in an attempt to get a principled notion of logical system? Another approach, the one we take here, is to look at the existing logical systems that people happened to have developed and to try to see what they were up to in more general terms. Our hope is to find some interesting natural phenomenon lurking behind these systems, a “natural kind,” if you will. If there is such a natural phenomenon, it could be used to guide the formulation of an abstract notion of logical system. If a characterization of logical systems could be found using this approach, it would have potentially two significant advantages over the more orthodox approach. First, it would provide a basis from which one could give a principled critique of existing systems claimed to be logical systems. Second, though, it would point out gaps, that is, logical systems which have yet to be developed.

Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1525-1535 ◽  
Author(s):  
Eugene A. Nosal

The vertical response function of induction logging tools is shown to be derivable from a power spectrum analysis of the measurement. The vertical response function is the one‐dimensional sequence of weights that characterizes how the tool combines the rock conductivities along the borehole to form an output called the apparent conductivity; it is the system impulse response. The value of knowing this function lies in the possible use of filter theory to aid in data processing and interpretation. Two general notions establish the framework for the analysis. The first is that logging is a linear, convolutional operation. Second, the earth’s conductivity profile forms a stochastic process. The probabilistic component is fleshed out by reasonably based assumptions about the occurrence of bed boundaries and nature of conductivity changes across them. Brought together, these tenets create a characterization of the conductivity sequence that is not a stationary process, but rather is intrinsic, as defined in the discipline of geostatistics. Such a process is described by a variogram, and it is increments of the process that are stationary. The connection between the power spectrum of the measurement and the system response function is made when the convolutional model is merged with the conductivity process. Some examples of induction log functions are shown using these ideas. The analysis is presented in general terms for possibly wider application.


2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Yoan Martínez Márquez ◽  
Yalice Gámez Batista ◽  
Norberto Valcárcel Izquierdo

Las TIC median las interacciones y la comunicación de los estudiantes a diario. Se conciben como mediado-ras de la reflexión y la autorregulación de la actividad del estudiante, resultante de la interacción consciente de la percepción que tiene el estudiante sobre si con la que negocia con el resto de los estudiantes, los ase-sores y la sociedad en general. En este contexto el aprovechamiento de las TIC debe promover una influen-cia formativa en los espacios formales y no formales. Las condicionantes de complementariedad de espa-cios y de unidad en la diversidad de recursos tecnológicos y didácticos deben guiar la actividad que tenga al estudiante como centro de la misma.Ya no se trata de integrar las TIC en el proceso de formación, haciéndolo formal y estandarizado. El reto está en que sean las características personales de los estudiantes, sus estilos de aprendizaje, sus conoci-mientos y experiencias previas, y sus esquemas afectivos los que marquen el aprovechamiento de las TIC en la evaluación del aprendizaje autónomo de inglés.En el presente trabajo se estructura el aprovechamiento de las TIC mediante un EPA base para la evalua-ción del aprendizaje autónomo de inglés. El EPA base constituye un andamiaje de personas, procedimien-tos, espacios de interacción, y de recursos tecnológicos y didácticos. Los componentes que lo conforman se encuentran débilmente acoplados por la tecnología y altamente cohesionados por la significatividad de las conexiones que el estudiante establece entre ellos. Palabras Clave: Aprendizaje, Autonomía, Entorno, Evaluación, Personal. ABSTRACT There is no doubt about the key role of ICT in the interaction and communication processes among students. ICT are thought as a mean for the reflection and self-regulation of students´ activity, which is in a permanent conscientious comparison between the perception a student has about him/herself and the one he/she nego-tiates with the rest of students, advisors and society in general terms. In this context, ICT should promote a positive influence on student formation in formal and non-formal spaces. The conditionals related to spaces combined support and union in the diversity of technological and didactical resources should guide every activity having students at the center of its conception.It is no longer about integrating ICT to the formation process making it formal and standardized. The chal-lenge on autonomous language learning evaluation with ICT has to do with making the differences through personal characteristics of students, their learning styles, previous experiences and affective schemas.In this paper the use of ICT is structured by means of a PLE frame for the evaluation of English autonomous language learning. It is a scaffolding of people, procedures, interaction spaces, and technological and didac-tical resources. Its components are weakly coupled by technologies and highly cohesive by the meaningful connections students establish among them. Keywords: Learning, Autonomy, Evaluation, Environment, Personal. Recibido: septiembre de 2016Aprobado: noviembre de 2016


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.


2021 ◽  
pp. 009524432110061
Author(s):  
Bo Yang ◽  
Balakrishnan Nagarajan ◽  
Pierre Mertiny

Polymers may absorb fluids from their surroundings via the natural phenomenon of swelling. Dimensional changes due to swelling can affect the function of polymer components, such as in the case of seals, microfluidic components and electromechanical sensors. An understanding of the swelling behavior of polymers and means for controlling it can improve the design of polymer components, for example, for the previously mentioned applications. Carbon-based fillers have risen in popularity to be used for the property enhancement of resulting polymer composites. The present investigation focuses on the effects of three carbon-based nano-fillers (graphene nano-platelets, carbon black, and graphene nano-scrolls) on the dimensional changes of polydimethylsiloxane composites due to swelling when immersed in certain organic solvents. For this study, a facile and expedient methodology comprised of optical measurements in conjunction with digital image analysis was developed as the primary experimental technique to quantify swelling dimensional changes of the prepared composites. Other experimental techniques assessed polymer cross-linking densities and elastic mechanical properties of the various materials. The study revealed that the addition of certain carbon-based nano-fillers increased the overall swelling of the composites. The extent of swelling further depended on the organic solvent in which the composites were immersed in. Experimental findings are contrasted with published models for swelling prediction, and the role of filler morphology on swelling behavior is discussed.


1963 ◽  
Vol 22 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Joan Bondurant

The title of this essay begins with the word traditional and it moves towards the idea of change. As is well known, these terms—tradition and change—are not opposites, nor are they to be understood in contradistinction to one another. It is important in this context to avoid the temptation to treat them as contradictory or to draw contrasts between what one considers on the one hand traditional, and on the other, changing. One cannot accurately speak of what was as over against what will be, or what is becoming. Nor can one view the ancient as opposed to that which is modern. Clearly, the opposite of change is permanence and persistence, and is not—at least not necessarily—to be couched in terms of the traditional. One need only to remind oneself that among the most compelling elements in the West's intellectual history is the idea of progress, to understand that there are indeed traditions in which the notion of change itself has played a significant role. And so it does not follow that "traditional Indian polity" is a set of concepts to be placed over against the "dynamics of change"—quite the contrary, as I shall try to show in what follows.


Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2967
Author(s):  
Seunghoon Choi ◽  
Sungjin Park ◽  
Minjoo Park ◽  
Yerin Kim ◽  
Kwang Min Lee ◽  
...  

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4–10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20–60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4–0.6 mm width.


2020 ◽  
Vol 70 (6) ◽  
pp. 1275-1288
Author(s):  
Abd El-Mohsen Badawy ◽  
Miroslav Haviar ◽  
Miroslav Ploščica

AbstractThe notion of a congruence pair for principal MS-algebras, simpler than the one given by Beazer for K2-algebras [6], is introduced. It is proved that the congruences of the principal MS-algebras L correspond to the MS-congruence pairs on simpler substructures L°° and D(L) of L that were associated to L in [4].An analogy of a well-known Grätzer’s problem [11: Problem 57] formulated for distributive p-algebras, which asks for a characterization of the congruence lattices in terms of the congruence pairs, is presented here for the principal MS-algebras (Problem 1). Unlike a recent solution to such a problem for the principal p-algebras in [2], it is demonstrated here on the class of principal MS-algebras, that a possible solution to the problem, though not very descriptive, can be simple and elegant.As a step to a more descriptive solution of Problem 1, a special case is then considered when a principal MS-algebra L is a perfect extension of its greatest Stone subalgebra LS. It is shown that this is exactly when de Morgan subalgebra L°° of L is a perfect extension of the Boolean algebra B(L). Two examples illustrating when this special case happens and when it does not are presented.


Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Gaetano Festa ◽  
Guido Maria Adinolfi ◽  
Alessandro Caruso ◽  
Simona Colombelli ◽  
Grazia De Landro ◽  
...  

Seismic sequences are a powerful tool to locally infer geometrical and mechanical properties of faults and fault systems. In this study, we provided detailed location and characterization of events of the 3–7 July 2020 Irpinia sequence (southern Italy) that occurred at the northern tip of the main segment that ruptured during the 1980 Irpinia earthquake. Using an autocorrelation technique, we detected more than 340 events within the sequence, with local magnitude ranging between −0.5 and 3.0. We thus provided double difference locations, source parameter estimation, and focal mechanisms determination for the largest quality events. We found that the sequence ruptured an asperity with a size of about 800 m, along a fault structure having a strike compatible with the one of the main segments of the 1980 Irpinia earthquake, and a dip of 50–55° at depth of 10.5–12 km and 60–65° at shallower depths (7.5–9 km). Low stress drop release (average of 0.64 MPa) indicates a fluid-driven initiation mechanism of the sequence. We also evaluated the performance of the earthquake early warning systems running in real-time during the sequence, retrieving a minimum size for the blind zone in the area of about 15 km.


Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Mariana Lemos ◽  
Teresa Valente ◽  
Paula Marinho Reis ◽  
Rita Fonseca ◽  
Itamar Delbem ◽  
...  

For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Uasmim Lira Zidanes ◽  
Matheus Cordazzo Dias ◽  
Mário Sérgio Lorenço ◽  
Elesandra da Silva Araujo ◽  
Maryella Júnnia Ferreira e Silva ◽  
...  

AbstractAdhesives based on vegetable tannins are already a reality in the market. However, their use is still limited due to their low mechanical resistance and weak humidity resistance. Cellulose nanofibrils (CNFs) are being used as reinforcing materials in various composites, resulting in an improvement of mechanical proprieties in general. The objective of this work was to evaluate the incorporation of CNFs in adhesives made of tannins obtained from the Angico tree (Anadenanthera peregrine). Concentrations of nanofibrils at 1, 5, and 10% were added to the adhesives on a dry basis. Tests of viscosity, pH, solids content, and gel time were performed to determine the physical proprieties of the adhesives. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Raman spectra measurements were also determined to understand the interaction between tannins and CNFs. Thermogravimetric analyses (TGA) were carried out to determine the thermal resistance of the composite. The FTIR and Raman characterization identified some differences in the peaks in the chemical composition of the adhesives with different percentages of CNFs. The adhesives showed no different decomposition in the thermogravimetric analyses. The shear strength in the glue line of the adhesive with 5% of CNFs in Toona ciliata woods was determined. Among all the adhesives analyzed, the one with 5% of CNFs produced an improvement in the mechanical resistance and humidity resistance on the glue line.


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