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نویسندگان: 

Hattiangadi Jagdish

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    17
  • شماره: 

    42
  • صفحات: 

    107-126
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    122
  • دانلود: 

    15
چکیده: 

Critical rationalism faces difficulty in Karl Popper’s Socratic formulation: “I may be wrong, and you may be right, and by an effort, we may find the truth.” But the Socratic elenchus, using refutations, can only give us negative knowledge of general principles, which is not the wisdom we seek. Affirmatively, we can only find a collection of opinions to be coherent, which is one of many. Francis Bacon proposed an improved elenchus to find general truths. You must take up a limited topic to study, then cross-examine your evidence for and against its apparent nature. Experiments contrary to evidence and presumed knowledge are entered as self-contradictions in tables of opposition recorded in an “Experimental and natural history.” Such an account highlights a challenging puzzle if the account is to be made coherent. With enough problematized evidence, a coherent reading, or a solution of the puzzle, will be unique. Being both coherent and unique, it will be the truth about that limited reality being investigated. Unlike the method of hypothesis (“Anticipating Nature”), deciphering a coherent model is “Interpreting Nature,” allowing us to find a general truth on a limited topic. Isaac Newton achieved great success using Robert Boyle’s mechanistic version of this method. Using the “Experimental philosophy,” he discovered general principles of optics and astronomy.

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اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    14
  • شماره: 

    1
  • صفحات: 

    91-95
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    296
  • دانلود: 

    0
چکیده: 

This article describes a workflow executed with MATLAB simulation and practical measurements for single phase power transformer. In addition, no-load, short-circuit test and load test are achieved in this work. The test procedures are implemented on a real transformer (terco– type) which has specifications of (1KVA, 220/110V, 50Hz). Finally, the simulation results are appeared proximately similar from the practical results.

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نویسندگان: 

نشریه: 

Heliyon

اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    5
  • شماره: 

    3
  • صفحات: 

    0-0
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    27
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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نویسندگان: 

KAHNEMAN D. | KNETSCH J.L. | THALER R.

اطلاعات دوره: 
  • سال: 

    1990
  • دوره: 

    98
  • شماره: 

    6
  • صفحات: 

    1325-1348
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    202
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 202

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نویسندگان: 

LI X. | HALLETT S.R. | WISNOM M.R.

اطلاعات دوره: 
  • سال: 

    2009
  • دوره: 

    40
  • شماره: 

    12
  • صفحات: 

    1891-1899
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    100
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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بازدید 100

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اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    19
  • شماره: 

    6
  • صفحات: 

    155-168
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    54
  • دانلود: 

    0
چکیده: 

With increasing urban population, the need for underground spaces increases and deep excavation is an inevitable affair in civil projects. deep tunnels and large buildings require deep excavations, which is a must use some techniques for stabilize it. grouted soil nail is a popular reinforcement to stabilize slopes, excavations and retaining walls. This method has been introduced to Hong Kong in the mid-1980s and has become an alternative solution to the conventional slope stabilizing methods such as compaction, earth retaining structure, or reduced inclination of the slope, etc. this method is based on sewing the potential failure wedge of soil on the stable soil using some inactive (un-prestressed) elements. the shear strength-displacement behavior at the interface between the grouted nail and surrounding soil is an important parameter in design of various geotechnical engineering projects, for example, soil nails, retaining walls, shallow foundations, pile foundations, etc. in soil nail system, the most common method to measure the interface shear strength is pullout test. It is also possible to determine the interface strength based on the development of resistance between soil and grout in direct shear Tests. However, accurate perception of the shear behavior in the connection area of the soil and grout is essential to reach an optimum design. In other words, the interaction between soil and grouted nail is necessary to design an optimum soil nail system. the most common method for determination grouted soil interface resistance is pullout test but there is another experiment that can yield acceptable results. The current study investigates the interface shear behavior between cement-grout and granular soil in direct shear test with different grout pressures ( 0 up to 2 bar) and different overburden pressures (100 up to 300 ,kPa). For this purpose, a number of direct shear Tests are performed by modifying of the standard shear box for injection of grout. “, Firozkooh”,sand is used in this study. The soil is compacted to the relative density of 90 % and the slurry is sprayed with pressure on its surface. Furthermore, results of two pullout Tests were used for verification. These pullout test have already been presented in another study with different normal stress and grout pressure. it is shown that the results of direct shear test and pullout test at interface are similar. this may indicate the proper function of direct shear test as a suitable choice alongside pullout test. It was observed that shear stress–, displacement curves of the soil-grout interface in direct shear Tests are similar to the soil-soil Tests,which are classified under different grouting pressures. In addition, increasing grout pressure increases shear strength by increasing the angle of friction and bonding of soil and slurry. The effect of adhesion is dominant. it is shown that The interface shear stress under different grouting pressures is greater than the shear stress of soil under the same normal stresses. it is shown that grouting pressure and normal stress have influence on the behavior of soil-cement interface. Therefore, interface shear strength increases with increase in overburden and injection pressure. The variation of the interface shear strength is approximately linear versus grouting pressure. Finally, a formula is proposed for interface shear strength considering grouting pressure.

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نویسندگان: 

ADIB A. | SHAFAI BEJESTAN M. | SHIRI V.

اطلاعات دوره: 
  • سال: 

    2019
  • دوره: 

    7
  • شماره: 

    1
  • صفحات: 

    21-34
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    136
  • دانلود: 

    0
چکیده: 

In this article a physical model is presented. A trapezoidal shape of channel with 1. 45 m width, 1 meter depth and banks slope of 1H: 1. 5V was applied. Circular piers (6, 8 and 10cm diameter) were examined under three dissimilar flow discharges of 50, 65 and 80 lit/s and three different median bed material sizes equal to 0. 94, 1. 31 and 2. 12 mm. Seven different longitude distance to pier diameter ratios (1, 1. 5, 2, 2. 5, 3, 4 and 5) were examined. Measurement of scour depth (upstream, around and downstream of pier) was accomplished in 10, 15, 20, 30, 60, 120, 240 and 360 minutes from the beginning of each examination. The results indicated that 30%-40%, up to 65% and more than 90% of local scour occurs at first two, 10, 120 and 200 minutes from the beginning of test respectively. The effect of dissimilar parameter especially the distance between piers on scour depth at group piers in series was evaluated and the results were compared to other researchers. It was found that our results is best fitted with the general form of well known Sheppard et al. (2004)’ s equation.

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نویسندگان: 

JIANG F.C. | VECCHIO K.S.

نشریه: 

APPLIED MECHANICS REVIEWS

اطلاعات دوره: 
  • سال: 

    2009
  • دوره: 

    62
  • شماره: 

    6
  • صفحات: 

    60802-60839
تعامل: 
  • استنادات: 

    1
  • بازدید: 

    133
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

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نویسندگان: 

Norouzi Larsari Vahid

اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    17
  • شماره: 

    45
  • صفحات: 

    215-230
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    165
  • دانلود: 

    54
چکیده: 

Postmodernism represents skepticism toward metanarratives and universal ideologies that dominated the modernist era. The study focuses on three key postmodernist concepts - alternative assessment, process syllabi, and self-directed learning. Alternative assessment emphasizes evaluating the learning process over summative testing. Process syllabi focus on the learning experience rather than rigid outcomes. Self-directed learning enables student responsibility in setting learning goals and processes. This paper examined the effects of postmodernist educational concepts on improving Iranian EFL learners’ autonomy. A quasi-Experimental pre-test/post-test design was utilized with 60 intermediate level Iranian EFL students divided into an Experimental and control group (n=30 each). The Experimental group received instruction utilizing the three postmodernist concepts over 14 weeks, while the control group received traditional modernist instruction. Autonomy was measured using a validated questionnaire before and after the intervention. The results showed the Experimental group demonstrated significant increases in autonomy compared to the control group. Paired sample t-Tests revealed significant differences between pre-test and post-test autonomy for the Experimental group across all three postmodern concepts - alternative assessment, process syllabi, and self-directed learning. This suggests postmodernist concepts that decentralize instruction and emphasize student process over outcomes can enhance Iranian EFL learners’ self-direction and responsibility for language acquisition. The study implies EFL syllabus designers and instruction should transition to postmodern models centered on individualized assessment, flexible syllabi, and student-guided learning to boost autonomy. Further research can expand sample sizes and explore additional postmodernist concepts across diverse demographics.

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نویسندگان: 

HASSANLOU RAD M. | VOSOUGHI M. | SARRAFI A.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    47
  • شماره: 

    2
  • صفحات: 

    239-253
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    290
  • دانلود: 

    0
چکیده: 

In this paper, the grouting ability of sandy soils is investigated by artificial neural networks based on the results of chemical grout injection Tests. In order to evaluate the soil grouting potential, Experimental samples were prepared and then injected. The sand samples with three different particle sizes (medium, fine, and silty) and three relative densities (%30, %50, and %90) were injected with the sodium silicate grout with three different concentrations (water to sodium silicate ratio of 0.33, 1, and 2). A multi-layer Perceptron type of the artificial neural network was trained and tested using the results of 138 Experimental Tests. The multi-layer Perceptron included one input layer, two hidden layers and one output layer. The input parameters consisted of initial relative densities of grouted samples, the average size of particles (D50), the ratio of the grout water to sodium silicate and the grout pressure. The output parameter was the grout injection radius. The results of the Experimental Tests showed that the radius of grout injection is a complicated function of the mentioned parameters. In addition, the results of the trained artificial neural network showed to be reasonably consistent with the Experimental results.

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