Search Result

14840

Results Found

Relevance

Filter

Newest

Filter

Most Viewed

Filter

Most Downloaded

Filter

Most Cited

Filter

Pages Count

1484

Go To Page

Search Results/Filters    

Filters

Year

Banks



Expert Group











Full-Text


مرکز اطلاعات علمی SID1
اسکوپوس
دانشگاه غیر انتفاعی مهر اروند
ریسرچگیت
strs
Author(s): 

KETABI N. | FATEMI J.

Journal: 

SCIENTIA IRANICA

Issue Info: 
  • Year: 

    2009
  • Volume: 

    16
  • Issue: 

    3 (TRANSACTION B: MECHANICAL ENGINEERING)
  • Pages: 

    269-272
Measures: 
  • Citations: 

    0
  • Views: 

    91733
  • Downloads: 

    114898
Abstract: 

In this paper, we present a Mont Carlo simulation by using the inhomogeneous diffusion equation suggested by Lagutin et al. in a FRACTAL interstellar MEDIUM for a supernova, as being the main source of Galactic cosmic rays in an energy range up to 1016ev. When the numerical results of this simulation are compared with the predicted energy density of cosmic rays from the supernova model of Erlikyn and Wolfendale (EW), they show a strong consistency with the observed experimental parameters of cosmic rays, i.e. Galactic radial gradient, percentage of total supernova energy transfer to cosmic particles etc., which is also confirmation of a supernova being of cosmic ray origin.

Yearly Impact:

View 91733

Download 114898 Citation 0 Refrence 0
Issue Info: 
  • Year: 

    2016
  • Volume: 

    7
  • Issue: 

    2
  • Pages: 

    385-402
Measures: 
  • Citations: 

    0
  • Views: 

    480
  • Downloads: 

    259
Abstract: 

IntroductionTwo main principal aspects for the genesis of porphyry copper deposits have been determined. The first genetic model concerns the petrologic and geochemical processes and the other relates the genesis to crustal deformation and geodynamic conditions (Kesler, 1997). Recent studies (e.g., Padilla Garza et al., 2001) show that the generation and emplacement of porphyry copper deposits may not only be dependent on magmatic and hydrothermal processes, but also that the regional and local tectonic setting plays an important role.

Yearly Impact:

View 480

Download 259 Citation 0 Refrence 0
Author(s): 

ZUO Yuting | Liu Zhongjun

Issue Info: 
  • Year: 

    2021
  • Volume: 

    7
  • Issue: 

    1
  • Pages: 

    13-18
Measures: 
  • Citations: 

    0
  • Views: 

    7078
  • Downloads: 

    5562
Abstract: 

The rheological property plays an important role in a free-form extrusion 3D printing process, no rheological model was available in open literature that could effectively take into account effects of both the non-Newtonian viscosity and the concentration of nano/micro particles in a paste. Here a FRACTAL law for non-Newtonian fluids is suggested using a FRACTAL derivative, the law can predict correctly the boundary effect of a viscous flow, and can model effectively the nonlinear velocity distribution across the section. A systematic derivation of a FRACTAL rheological model is suggested using the basic laws in the fluid mechanics, which can provide a deep insight into the two-scale FRACTAL interpretation of non-Newtonian fluids. An experiment was carefully designed to verify the model and to elucidate the relationship between the shear rate and viscosity of the SiC paste. 15wt. %, 25wt. %, 35wt. % and 45wt. % SiC pastes were prepared by using mixing, stirring and ball milling processes. The rheology of the paste can be controlled primarily through the SiC concentration, which affects the FRACTAL order. The FRACTAL model sheds a bright light on a simple but accurate approach to non-Newtonian fluids.

Yearly Impact:

View 7078

Download 5562 Citation 0 Refrence 0
گارگاه ها آموزشی
Author(s): 

DELIREZH NOWRUZ | ASADI BEHNAZ

Issue Info: 
  • Year: 

    2012
  • Volume: 

    21
  • Issue: 

    SUPPLEMENT 1
  • Pages: 

    51-65
Measures: 
  • Citations: 

    607
  • Views: 

    614
  • Downloads: 

    472
Abstract: 

Background and purpose: Several laboratories have developed culture systems including maturation factors for human DC from peripheral blood monocytes. We comprehensively studied the effect of addition of poly (I-C) to standard maturation stimulus, MCM and TNF-a on maturation of monocyte derived DCs and their ability to elicit T cell responses.Materials and methods: A short (4-day) priming of plastic adherent monocytes with granulocytemacrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) followed by allogenic tumor antigen pulsing and addition of MCM and TNF-a with or without poly (I-C) to generate fully mature and stable DCs. Phenotypic and functional analysis were carried out using anti CD14, HLA-DR and CD83 monoclonal antibodies, mixed lymphocyte reaction (MLR), phagocytic activity and cytokine release by DC stimulated T lymphocytes.Results: We found that fully matured DCs with large amount cytoplasm and copious dendritic projections were visible at the end of culturing period in the presence of MCM and TNF-a with or without rpoly (I-C). Flow cytometric analysis using anti-CD14, HLA-DR and CD83 revealed that addition of poly (I-C) to conventional maturation factors results in decreased expression of CD14 and increased expression of HLA-DR and CD83. Functionally, MCM and TNF-a with poly (I-C) treated DCs showed a little stronger mixed leukocyte reaction Analysis of phagocytic activity showed that addition of poly (I-C) reduced FITC-conjugated bead uptake and increased mean fluorescent intensity (MFI) of phagocytic DCs. Furthermore our results revealed that additional treatment of DCs with poly (I-C) results in reduction of IL-12: IL-10 and IFN-γ: IL-4 ratios in DC and DC-primed T cell supernatants respectively.Conclusion: Our results support this idea that use of the MCM, TNF-a and poly (I-C) as maturation factor could gnerates more mature monocyte derived DCs that prime T lymphocytes to TH2 type cytokine release.

Yearly Impact:

View 614

Download 472 Citation 607 Refrence 0
Journal: 

WATER ENGINEERING

Issue Info: 
  • Year: 

    2020
  • Volume: 

    13
  • Issue: 

    45
  • Pages: 

    81-100
Measures: 
  • Citations: 

    0
  • Views: 

    1983
  • Downloads: 

    20698
Abstract: 

Density current is caused by a slight density difference with the environmental fluid. These currents are of two-phase current type. These currents are non-linear in nature, which are complex and sensitive to initial conditions. FRACTAL geometry is used as a powerful tool to investigate geophysical phenomena including density current and many complex natural phenomena. This study aimed to conduct a comprehensive study on the FRACTAL and multi-FRACTAL properties of density current and established a significant relation between the Richardson number evolution and the entrainment of ratio density current through FRACTAL analysis. For this purpose, three experimental models in 28 different states were performed by changing the bed slope, density and inlet discharge. The developed codes in MATLAB were used to calculate the multi-FRACTAL generalized dimension indices D(q), singularity spectrum f(α, ), singularity angle α, , the scaling exponent T(q) and FRACTAL dimension Df. The results and various investigations indicated that the FRACTAL dimension decreased a little with the increase of flume bed slope. Further, the FRACTAL dimension increases with increasing the concentration and current discharge. As the Richardson number increases, the scaling exponent has a linear pattern. Furthermore, the FRACTAL dimension changes are monotonic than q in these experiments, and the singularity angles are larger with less range. A significant relationship with 92% coefficient was made between Richardson number and entrainment ratio by FRACTAL analysis.

Yearly Impact:

View 1983

Download 20698 Citation 0 Refrence 0
Issue Info: 
  • Year: 

    2008
  • Volume: 

    7
  • Issue: 

    2
  • Pages: 

    134-136
Measures: 
  • Citations: 

    0
  • Views: 

    129692
  • Downloads: 

    39913
Abstract: 

In recent few years FRACTALs have been employed in conjunction with antennas to develop new applications. In this work, novel FRACTAL geometry is introduced as a miniaturized microstrip patch antenna. Compared to a square patch antenna, the antenna shows an improvement of 68% size reduction. Furthermore, by applying of a new feeding method, refereed to here as the sleeve feeding, up to 27% impedance bandwidth is achieved as shown in the experiments.

Yearly Impact:

View 129692

Download 39913 Citation 0 Refrence 0
strs
Issue Info: 
  • Year: 

    2021
  • Volume: 

    1
  • Issue: 

    1
  • Pages: 

    159-178
Measures: 
  • Citations: 

    0
  • Views: 

    5946
  • Downloads: 

    4107
Abstract: 

In this article, the price adjustment equation has been proposed and studied in the frame of FRACTAL calculus which plays an important role in market equilibrium. FRACTAL time has been recently suggested by researchers in physics due to the self-similar properties and fractional dimension. We investigate the economic models from the viewpoint of local and non-local FRACTAL Caputo derivatives. We derive some novel analytical solutions via the FRACTAL Laplace transform. In FRACTAL calculus, a useful local FRACTAL derivative is a generalized local derivative in the standard computational sense, and the non-local FRACTAL Caputo FRACTAL derivative is a generalization of the non-local fractional Caputo derivative. The economic models involving FRACTAL time provide a new framework that depends on the dimension of FRACTAL time. The suggested FRACTAL models are considered as a generalization of standard models that present new models to economists for fitting the economic data. In addition, we carry out a comparative analysis to understand the advantages of the FRACTAL calculus operator on the basis of the additional FRACTAL dimension of time parameter, denoted by $alpha$, which is related to the local derivative, and we also indicate that when this dimension is equal to $1$, we obtain the same results in the standard fractional calculus as well as when $alpha$ and the nonlocal memory effect parameter, denoted by $gamma$, of the nonlocal FRACTAL derivative are both equal to $1$, we obtain the same results in the standard calculus.

Yearly Impact:

View 5946

Download 4107 Citation 0 Refrence 0
Author(s): 

JAM S. | MEHBOODI A.

Issue Info: 
  • Year: 

    2017
  • Volume: 

    15
  • Issue: 

    2
  • Pages: 

    143-149
Measures: 
  • Citations: 

    0
  • Views: 

    1353
  • Downloads: 

    494
Abstract: 

For further and various applications of communication systems, we lead to using the overall of electromagnetic spectrum. Also, because of the developing f multiband wireless systems, antenna designers are enforced to design antennas matched to the operation in multi-band and multi-frequency. On the other hand, nowadays, the use of light-weight, simple, small and inexpensive antennas is an essential requirement for covering multi bands. In this paper, a microstrip antenna is designed and suggested FRACTAL-based and utilized FR4 substrate with small size and light, and also ability to resonance in multi-frequency by increasing FRACTAL repetitions and self-similarity property. Therefore, this proposed structure causes the antenna resonance in more frequencies, and also leads to miniaturization of its size. This antenna operates in 1-10 GHz range includes five frequency resonance for the most of convenient applications. Also, it has appropriate pattern and circular polarization which increases its applications. The antenna has been fabricated and there is a good agreement between measurement results and full wave simulation using HFSS software.‏

Yearly Impact:

View 1353

Download 494 Citation 0 Refrence 1
Issue Info: 
  • Year: 

    2019
  • Volume: 

    5
  • Issue: 

    1
  • Pages: 

    57-72
Measures: 
  • Citations: 

    0
  • Views: 

    1205
  • Downloads: 

    255
Abstract: 

Summary The East Azarbaijan geothermal area is located in northwest of Iran, which hosts several hot springs. It is situated mostly around the Sabalan and Sahand mountains. The Sabalan and Sahand geothermal area is now under investigation for the geothermal electric power generation. It is characterized by high thermal gradient and high heat flow. In this study, our aim is to determine the FRACTAL parameter and top and bottom depths of the magnetic sources. A modified spectral analysis technique named “ de-FRACTAL spectral depth method” is developed and used to estimate the top and bottom depths of the magnetized layer. A mathematical relationship is used between the observed power spectrum (due to FRACTAL magnetization) and an equivalent random magnetization power spectrum. The de-FRACTAL approach removes the effect of FRACTAL magnetization from the observed power spectrum, and estimates the parameters of the depth to top and depth to bottom of the magnetized layer using iterative forward modelling of the power spectrum. This approach is applied to the aeromagnetic data of the East Azarbaijan Province. The obtained results indicated variable magnetic bottom depths ranging from 9. 8 km to about 16. 8 km. In addition, the FRACTAL parameter was found to vary from 1. 6 to 3 within the study area...

Yearly Impact:

View 1205

Download 255 Citation 0 Refrence 0
Issue Info: 
  • Year: 

    2005
  • Volume: 

    4
  • Issue: 

    3
  • Pages: 

    235-243
Measures: 
  • Citations: 

    0
  • Views: 

    660
  • Downloads: 

    163
Abstract: 

Patterns formed by the flow of an inhomogeneous fluid (suspension) over a smooth inclined surface were studied. It was observed that FRACTAL patterns formed. There exists a threshold angle for the inclination above which, global FRACTAL patterns are formed. This angle depends on the particle size of the suspension. We observed that there are two FRACTAL dimensions for these patterns, depending on the area from which the pattern is extracted. If the pattern is taken from the top which only consists of the beginning stages of the pattern forming, one finds two FRACTAL dimensions i.e. 1.35-1.45 and 1.6-1.7, in which the first one is dominant. And if the entire pattern is taken, then FRACTAL dimension 1.6-1.7 is observed. The first FRACTAL dimension belongs to the class of flow of water over an inhomogeneous surface, and the second one corresponds to the river network. This may imply that both universality classes are present. However, disorder is present in the fluid and is transferred to the surface. We have also determined the FRACTAL dimension of the patterns formed below the threshold angle. We find it to be between 1.57 to 1.7.

Yearly Impact:

View 660

Download 163 Citation 0 Refrence 0
litScript