scholarly journals Fisuras de contracción en pavimentos de hormigón y el aserrado de juntas

2013 ◽  
Vol 3 (2) ◽  
pp. 111-121
Author(s):  
M. F. Barreda ◽  
M. J. Naber ◽  
I. Quispe Sallo ◽  
J. D. Sota
Keyword(s):  
A Priori ◽  
Ultrasonic Pulse ◽  
Optimal Time ◽  
Hardened Concrete ◽  
Concrete Pavements ◽  
Maintenance Costs ◽  
Shrinkage Cracks ◽  
Contraction Joints ◽  
First Results ◽  
The Right

RESUMENLos cambios volumétricos por variaciones de temperatura y contenido de humedad en el hormigón endurecido de los pavimentos, que por sus restricciones impiden su deformación, causan tensiones de tracción, provocando fisuras aleatorias. La presencia de fisuras de contracción en los pavimentos de hormigón, reducen su vida útil y generan costos de mantenimiento importantes. Es necesario definir a priori la ubicación de las fisuras aserrando el pavimento. Las zonas aserradas crean planos de debilidad donde se forman las fisuras, siendo crítico el momento oportuno para realizar el aserrado de las juntas de contracción en los pavimentos. El período óptimo para efectuar el aserrado se denomina ventana de aserrado. El objetivo de este trabajo es (poner objetivo). Entre los resultados obtenidos se puede decir que (dar resultados). Los estudios son parte de un Proyecto de I+D.Palabras Clave: contracción; hormigón; pavimentos; juntas; fisuras.ABSTRACTIn the hardened concrete of pavements, with limited deformation, volumetric changes due to variations in temperature and humidity cause tensile stresses, with subsequent cracks random. The presence of shrinkage cracks in concrete pavements, reduces its service life and generates substantial maintenance costs. It is necessary to define a priori the location of cracks, by sawing the pavement. Sawn areas create planes of weakness where cracks form, being critical the right time to saw the contraction joints in pavements. The optimal time to perform the sawing is called sawing window. In this paper the first results about concrete pavements are recorded, establishing sawing times, comparing cylindrical compressive strength, maturity of concrete and ultrasonic pulse values. The studies are part of a R & D project.Keywords: contraction; concrete; pavements; joints; cracks.

Towards 1-Ångstrom-resolution STEM

1993 ◽  
Vol 51 ◽  
pp. 996-997
Author(s):  
H.S. von Harrach ◽  
D.E. Jesson ◽  
S.J. Pennycook
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Phase Contrast ◽  
Spherical Aberration ◽  
A Priori ◽  
Dark Field ◽  
Image Resolution ◽  
Objective Lens ◽  
Annular Dark Field ◽  
First Results

Phase contrast TEM has been the leading technique for high resolution imaging of materials for many years, whilst STEM has been the principal method for high-resolution microanalysis. However, it was demonstrated many years ago that low angle dark-field STEM imaging is a priori capable of almost 50% higher point resolution than coherent bright-field imaging (i.e. phase contrast TEM or STEM). This advantage was not exploited until Pennycook developed the high-angle annular dark-field (ADF) technique which can provide an incoherent image showing both high image resolution and atomic number contrast.This paper describes the design and first results of a 300kV field-emission STEM (VG Microscopes HB603U) which has improved ADF STEM image resolution towards the 1 angstrom target. The instrument uses a cold field-emission gun, generating a 300 kV beam of up to 1 μA from an 11-stage accelerator. The beam is focussed on to the specimen by two condensers and a condenser-objective lens with a spherical aberration coefficient of 1.0 mm.

Construct Validity

2017 ◽  
Author(s):  
Richard McCleary ◽  
David McDowall ◽  
Bradley J. Bartos
Keyword(s):  
Time Series ◽  
Construct Validity ◽  
Hypothesis Test ◽  
Secondary Data ◽  
Time Frame ◽  
Primary Data ◽  
Optimal Time ◽  
Intervention Model ◽  
Right Hand ◽  
The Right

Chapter 8 focuses on threats to construct validity arising from the left-hand side time series and the right-hand side intervention model. Construct validity is limited to questions of whether an observed effect can be generalized to alternative cause and effect measures. The “talking out” self-injurious behavior time series, shown in Chapter 5, are examples of primary data. Researchers often have no choice but to use secondary data that were collected by third parties for purposes unrelated to any hypothesis test. Even in those less-than-ideal instances, however, an optimal time series can be constructed by limiting the time frame and otherwise paying attention to regime changes. Threats to construct validity that arise from the right-hand side intervention model, such as fuzzy or unclear onset and responses, are controlled by paying close attention to the underlying theory. Even a minimal theory should specify the onset and duration of an impact.

On Fourier Series in Eigenfunctions of Elliptic Boundary Value Problems

2003 ◽  
Vol 10 (3) ◽  
pp. 401-410
Author(s):  
M. S. Agranovich ◽  
B. A. Amosov
Keyword(s):  
Fourier Series ◽  
Boundary Conditions ◽  
Fourier Coefficients ◽  
Elliptic Boundary ◽  
A Priori ◽  
Adjoint Problem ◽  
Elliptic Boundary Value ◽  
Right Hand ◽  
The Difference ◽  
The Right

Abstract We consider a general elliptic formally self-adjoint problem in a bounded domain with homogeneous boundary conditions under the assumption that the boundary and coefficients are infinitely smooth. The operator in 𝐿2(Ω) corresponding to this problem has an orthonormal basis {𝑢𝑙} of eigenfunctions, which are infinitely smooth in . However, the system {𝑢𝑙} is not a basis in Sobolev spaces 𝐻𝑡 (Ω) of high order. We note and discuss the following possibility: for an arbitrarily large 𝑡, for each function 𝑢 ∈ 𝐻𝑡 (Ω) one can explicitly construct a function 𝑢0 ∈ 𝐻𝑡 (Ω) such that the Fourier series of the difference 𝑢 – 𝑢0 in the functions 𝑢𝑙 converges to this difference in 𝐻𝑡 (Ω). Moreover, the function 𝑢(𝑥) is viewed as a solution of the corresponding nonhomogeneous elliptic problem and is not assumed to be known a priori; only the right-hand sides of the elliptic equation and the boundary conditions for 𝑢 are assumed to be given. These data are also sufficient for the computation of the Fourier coefficients of 𝑢 – 𝑢0. The function 𝑢0 is obtained by applying some linear operator to these right-hand sides.

scholarly journals Repair and maintenance costs of 4WD tractors and self propelled combine harvesters in Italy

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Aldo Calcante ◽  
Luca Fontanini ◽  
Fabrizio Mazzetto
Keyword(s):  
Cost Estimation ◽  
Working Hours ◽  
The United States ◽  
Operating Conditions ◽  
List Price ◽  
Optimal Time ◽  
Model Parameters ◽  
Maintenance Costs ◽  
Combine Harvesters ◽  
Engine Power

Purchasing and maintaining tractors and operating machines are two of the most considerable costs of the agricultural sector, which includes farm equipment manufacturers, farm contractors and farms. In this context, repair and maintenance costs (R&M costs) generally constitute 10-15% of the total costs related to agricultural equipment and tend to increase with the age of the equipment; hence, an important consideration in farm management is the optimal time for equipment replacement. Classical, R&M cost estimation models, calculated as a function of accumulated working hours, are usually developed by ASAE/ASABE for the United States operating conditions. However, R&M costs are strongly influenced by farming practices, operative conditions, crop and soil type, climatic conditions, etc. which can be specific for individual countries. In this study, R&M cost model parameters were recalculated for the current Italian situation. For this purpose, data related to the R&M costs of 100 4WD tractors with engine power ranging from 59 to 198 kW, and of 20 SP combine harvesters (10 straw walkers combines and 10 axial flow combines) with engine power ranging from 159 to 368 kW working in Italy were collected. According to the model, which was obtained by interpolating the data through a two-parameter power function (proposed by ASAE/ASABE), the R&M cost incidence on the list price of Italian tractors at 12,000 working hours (estimated life of the machines) was 48.6%, as compared with 43.2% calculated through the most recent U.S. model while, for self propelled combine harvesters, the R&M cost incidence at 3,000 working hours was 23.1 % as compared with 40.2% calculated through the same U.S. model.

scholarly journals Realism and Knowledge First. Interview with Timothy Williamson

2022 ◽  
Vol 19 (3) ◽  
pp. 175-204
Author(s):  
I. E. Pris
Keyword(s):  
A Priori ◽  
Gettier Problem ◽  
Traditional Epistemology ◽  
Timothy Williamson ◽  
Skeptical Problem ◽  
Ill Posed ◽  
The Right ◽  
Metaphysical Realist ◽  
First Interview ◽  
The Gettier Problem

The renowned British philosopher Timothy Williamson talks about his philosophical views and main lines of research. Williamson is a metaphysical realist in a broad sense. Fir him there are true or false answers to questions about all aspects of reality. Classical logic is a universal true theory. Knowledge-first epistemology is an alternative to the traditional belief-first epistemology. The former takes the concept of knowledge as a basic concept, explaining other epistemic concepts, including belief, in its terms, whereas the latter does the opposite. Knowledge, not truth, is the fundamental epistemic good. The Gettier problem and the skeptical problem that arise within traditional epistemology are ill posed and therefore cannot be solved. Hybrid epistemological theories do not satisfy the principles of simplicity and beauty and are refuted by counter-examples. Epistemic contextualism is problematic, and relativism violates the semantics of the phenomena being explained. Knowledge does not entail knowledge about knowledge. Knowledge-how is a kind of knowledge-that. The distinction between a priori and a posteriori is superficial, and there are no analytical truths. The concept of qualia is unhelpful for solving the problems related to consciousness. The so-called “hard problem” of consciousness points to an area of conceptual confusions in which we do not know how to reason properly. Speculative metaphysics is quite a respectable enterprise. But progress in metaphysics is not automatic; it requires the right methodology.

scholarly journals REFORMS IN THE COMMUNICATIONS MONITORING SYSTEM AS A PRECONDITION FOR EFFECTIVE HUMAN RIGHTS PROTECTION

2019 ◽  
Vol 31 (5) ◽  
pp. 1509-1514
Author(s):  
Biljana Karovska-Andonovska ◽  
Zoran Jovanovski
Keyword(s):  
Monitoring System ◽  
A Priori ◽  
Personal Data ◽  
The Other ◽  
Right To Privacy ◽  
Human Rights Protection ◽  
Personal Data Protection ◽  
The Right To Privacy ◽  
The Right ◽  
And Control

The reforms in the communications monitoring system as part of the wider reform of the security services in the Republic of Macedonia, resulted with creation of a package of several laws whose adoption was supposed to provide the legislative basis for a system that would really work in accordance with the goals for which it was established. The communications monitoring system should provide a balanced protection of the right to security, on the one hand, and the right to privacy, on the other. Only on that way a priori primacy of the right to security over the right to privacy will it be disabled. Hence, the reforms in communications monitoring system are a precondition for the effective protection, primarily for the right to privacy and the secrecy of communications, but also for the right to personal data protection, the inviolability of the home as well as for the right to presumption of innocence. It is a complex and delicate matter where opening of a real debate through which the present deficiencies will be perceived in order to create an appropriate legal solutions was very important. However, the new Law on Interception of Communications as the most important in this area, retained a certain part of the provisions that were debatable in the previous legal solutions. The provisions regarding the model for interception of communications, which stipulates the establishment of a separate agency that mediates between the operators and the authorized bodies for interception of communications, were questionable as well. Also, new measures for monitoring communications in the interest of security and defense, as well as the provisions which regulate the disposition and delivery of metadata for security and defense, are also debatable. On the other side, the reform laws made an evident progress in a positive sense through the provisions for oversight and control over the interception of communications. With these changes, certain debatable elements have been overcome, especially those that have hindered it so far, and in some cases completely paralyzed the oversight and control over the monitoring of communications. In this paper we analyzed the debatable elements in the reform package of laws on interception of communications as well as some positive aspects contained in the provisions of the reform laws.

scholarly journals High Strength Nano Silica Based Concrete

2020 ◽  
Vol 9 (7) ◽  
pp. 1150-1155
Keyword(s):  
Electron Microscope ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Hardened Concrete ◽  
Nano Silica ◽  
Nano Structure ◽  
Transmission Electron

There is a substantial curiosity in academia, the investment community and among manufacturers about the exhilarating opportunities offered by nano materials. Although a lot of applications for nanotechnology remain hypothetical, construction is one area where numerous ‘here and now’ applications have already emerged. While existing use is restricted, the market is likely to approach more than 500 million dollars within ten years. Concrete is most likely exceptional in the construction field, that it is the distinct material exclusive to business and hence, is the recipient of a reasonable quantity of research and development capital from the construction industry. SiO2 (Silica) usually is an integral part of concrete in the normal mix. On the other hand, one of the innovations made by the study of concrete at nano scale level is that particle stuffing in concrete can be enhanced by means of adding nano silica (NS), which results in the densification of the micro and nano structure of cementitious composite resulting in enhanced mechanical properties. In this research paper, the result of a thorough investigational analysis on the utilization of NS in addition to cement so that the strength and quality of concrete can improve has been achieved. The effect of various proportions of NS in concrete has been premeditated to evaluate the properties of NS based hardened concrete according to the standard concrete. The obtained outcomes after testing indicate that the addition of NS together with concrete has improved the mechanical behavior of concrete. The NS blended high strength concrete (HSC) shows a better compressive strength (CS) of 66.00 N/mm2 (MPa) after standard twenty eight days, which is an exceptional development over standard concrete. Each and every mixture containing NS in various proportions gave enhanced outcomes in comparison with the standard predictable concrete. RH (Rebound Hammer), UPV (Ultrasonic Pulse Velocity), SEM (Scanning Electron Microscope) and TEM (Transmission Electron Microscope) examinations further authenticate the above results.

scholarly journals Implementation of Apriori Algorithm Data Mining for Increase Sales

SinkrOn ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 17
Author(s):  
Reza Alfianzah ◽  
Rani Irma Handayani ◽  
Murniyati Murniyati
Keyword(s):  
Data Mining ◽  
Business Strategy ◽  
A Priori ◽  
Data Mining Algorithm ◽  
Sales Data ◽  
The Right ◽  
Or Organization ◽  
Product Sales ◽  
The Relationship ◽  
Confidence Value

Any company or organization that wants to survive needs to determine the right business strategy. The product sales data carried out by Lakoe Dessert Pondok Kacang will eventually result in a pile of data, so it is unfortunate if it is not re-analyzed. The products offered vary with a wide variety of products as many as 45 products, to find out the products with the most sales and the relationship between one product and another, one of the algorithms is needed in the data mining algorithm, namely the a priori algorithm to find out, and with the help of the Rapidminer 5 application, with a support value 2,4% and a confidence value 50%, products that customers often buy or are interested in can be found. This study used sales data for March 2020, which amounted to 209 transaction data. From the research, it was found that the item with the name Pudding Strawberry and Pudding Vanilla was the product most purchased by consumers. With knowledge of the most sold products and the patterns of purchasing goods by consumers, Lakoe Dessert Pondok Kacang can develop marketing strategies to market other products by analyzing the profits from selling the most sold products and anticipating running out or empty of stock or materials at a later date.

scholarly journals Replacement Model for Street Lighting Systems

2021 ◽  
Vol 40 (1) ◽  
pp. 49-55
Author(s):  
A.M. Usman ◽  
Y.A. Adediran ◽  
A.O. Otuoze ◽  
O.O. Mohammed ◽  
O.S. Zakariyya
Keyword(s):  
Field Survey ◽  
Optimal Time ◽  
North Central ◽  
Street Lighting ◽  
Maintenance Costs ◽  
Optimal Replacement ◽  
Replacement Model ◽  
Lighting Systems ◽  
The University ◽  
Replacement Time

Replacing failed bulbs of streetlights in a location can be very tasking and expensive if the optimal time for replacement is not determined. In this paper, a model has been developed that helps to establish the optimal time for the replacement of streetlight bulbs. Burnt-out bulbs are replaced individually when they fail, and group replacement is carried out on all bulbs after a specified time. The costs for both individual replacement and group replacement are determined. The developed model was applied to locally sourced data from a field survey of a streetlight installation at the University of Ilorin, Ilorin, North-central Nigeria. The model gave the optimum replacement time of burnt-out bulbs as the eighteenth week when applied to the data used in this work. The optimum replacement time will be dependent on the dataset used. This makes the developed model useful in establishing the optimal replacement time of any stochastically failing items that are in large quantities. The model will help to reduce maintenance costs for facility managers.

Fundamental Solutions of PDEs as Radial Basis Functions in Multivariate Interpolation

2007 ◽  
Vol 7 (4) ◽  
pp. 321-340
Author(s):  
A. Masjukov
Keyword(s):  
Radial Basis Functions ◽  
Interpolation Method ◽  
A Priori ◽  
Fundamental Solutions ◽  
Basis Functions ◽  
Scale Parameters ◽  
Radial Basis ◽  
Undecidable Problem ◽  
The Right ◽  
Smooth Approximations

AbstractFor bivariate and trivariate interpolation we propose in this paper a set of integrable radial basis functions (RBFs). These RBFs are found as fundamental solutions of appropriate PDEs and they are optimal in a special sense. The condition number of the interpolation matrices as well as the order of convergence of the inter- polation are estimated. Moreover, the proposed RBFs provide smooth approximations and approximate fulfillment of the interpolation conditions. This property allows us to avoid the undecidable problem of choosing the right scale parameter for the RBFs. Instead we propose an iterative procedure in which a sequence of improving approx- imations is obtained by means of a decreasing sequence of scale parameters in an a priori given range. The paper provides a few clear examples of the advantage of the proposed interpolation method.

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