Statistical calculation of the geometrical factors in radiant transfer

1972 ◽  
Vol 23 (6) ◽  
pp. 1562-1565
Author(s):  
V. P. Fotin ◽  
F. R. Shklyar
Keyword(s):  
Statistical Calculation ◽  
Geometrical Factors ◽  
Radiant Transfer

Students’ Understanding of Generic Structure of the Text and the Quality of Writing: A Correlational Study

2019 ◽  
Vol 2 (1) ◽  
pp. 37-45
Author(s):  
Atikah Wati
Keyword(s):  
High School ◽  
Research Design ◽  
Senior High School ◽  
Second Grade ◽  
Statistical Calculation ◽  
Writing Quality ◽  
Generic Structure ◽  
Writing Test ◽  
Correlational Research

Indriyani et al, (2013) stated that many students had dificulty in understanding the generic structure of analytical exposition text. Therefore, the present study tried to investigate the correlation between students understanding in writing generic structure of analytical exposition and the quality of students’ writing in second grade of senior hight school. Grounded in explanatory correlational research design by Creswell (2011), this study conducted over two weeks in one of senior high school in Indramayu. Close-ended questionnaire and writing test were instruments to collect the data and it was analyzed  by using SPSS 22. The statistical calculation from students understanding in writing generic stucture of the text and writing test indicated that the value of tcount was 3.23 and the value of ttable was 0.361. It can be concluded that the hypothesis was accepted because tcount 3.23 > ttable 0.361. The finding reveal that there was middle correlation or middle prediction in students understanding of generic structure of analytical exposition and students writing quality with the score 0,52.

Radiant Heat Transfer From Isothermal Dispersions With Isotropic Scattering

1967 ◽  
Vol 89 (4) ◽  
pp. 300-308 ◽  
Author(s):  
R. H. Edwards ◽  
R. P. Bobco
Keyword(s):  
Heat Transfer ◽  
Approximate Solutions ◽  
Radiant Heat ◽  
Second Order ◽  
Isotropic Scattering ◽  
Radiant Heat Transfer ◽  
Approximate Methods ◽  
First Order ◽  
Order Solution ◽  
Radiant Transfer

Two approximate methods are presented for making radiant heat-transfer computations from gray, isothermal dispersions which absorb, emit, and scatter isotropically. The integrodifferential equation of radiant transfer is solved using moment techniques to obtain a first-order solution. A second-order solution is found by iteration. The approximate solutions are compared to exact solutions found in the literature of astrophysics for the case of a plane-parallel geometry. The exact and approximate solutions are both expressed in terms of directional and hemispherical emissivities at a boundary. The comparison for a slab, which is neither optically thin nor thick (τ = 1), indicates that the second-order solution is accurate to within 10 percent for both directional and hemispherical properties. These results suggest that relatively simple techniques may be used to make design computations for more complex geometries and boundary conditions.

scholarly journals Impact of pitch angle fluctuations on airborne lidar forward sensing along the flight direction

2017 ◽  
Vol 10 (10) ◽  
pp. 3851-3864 ◽  
Author(s):  
Alexander Sergeevich Gurvich ◽  
Victor Alexeevich Kulikov
Keyword(s):  
Pitch Angle ◽  
Beam Steering ◽  
Airborne Lidar ◽  
Civil Aviation ◽  
Aerosol Layer ◽  
Flight Direction ◽  
Air Turbulence ◽  
Shear Turbulence ◽  
Geometrical Factors ◽  
Vertical Scales

Abstract. Airborne lidar forward sensing along the flight direction can serve for notification of clear air turbulence (CAT) and help to prevent injuries or fatal air accidents. The validation of this concept was presented in the framework of the DELICAT (DEmonstration of LIdar-based CAT detection) project. However, the strong variations in signal level, which were observed during the DELICAT measurements but not explained, sometimes indicated the need of a better understanding the observational errors due to geometrical factors. In this paper, we discuss possible error sources pertinent to this technique, related to fluctuations of the flight parameters, which may lead to strong signal variations caused by the random deviations of the sensing beam from the forward flight trajectory. We analyze the variations in backscattered lidar signal caused by fluctuations of the most important forward-sensing flight parameter, the pitch angle. The fluctuation values considered in the paper correspond to the error limits of the compensational gyro platform used in civil aviation. The part of the pitch angle fluctuations not compensated for by the beam-steering device in the presence of aerosol concentration variations can lead to noticeable signal variations that can be mistakenly attributed to wind shear, turbulence, or fast evolution of the aerosol layer. We formulate the criteria that allow the recognition of signal variations caused by pitch angle fluctuations. Influence of these fluctuations is shown to be stronger for aerosol variations on smaller vertical scales. An example of DELICAT observations indicating a noticeable pitch angle fluctuation impact is presented.

Study on the Formation of Stray Grains during Directional Solidification of Nickel-Based Superalloys

2016 ◽  
Vol 879 ◽  
pp. 1582-1587 ◽  
Author(s):  
Maria Rita Ridolfi ◽  
Oriana Tassa ◽  
Giovanni de Rosa
Keyword(s):  
Directional Solidification ◽  
Gas Turbines ◽  
Complex Geometry ◽  
Turbine Blades ◽  
Columnar Dendrite ◽  
Affecting Factors ◽  
Stray Grains ◽  
Geometrical Factors ◽  
Stray Grain ◽  
The Impact

Ni-based superalloy single-crystal turbine blades are widely used in gas turbines for aircraft propulsion and power generation as they can be subjected to high service temperature and show high mechanical properties due to the almost total elimination of grain boundaries. Particularly in presence of complex geometry shapes, rare grains nucleating apart from the primary grain, become a serious problem in directional solidification, when characterized by high-angle boundaries with the primary grain, extremely brittle due the elevated amount of highly segregating elements and the absence of grain boundary strengthening elements. It is of fundamental importance analyzing the physical mechanisms of formation of stray grains, to understand which thermo-physical and geometrical factors highly influence their formation and to find possible ways to reduce the impact of the problem. In this paper, constrained dendrite growth and heterogeneous grain nucleation theories have been used to model the formation of stray grains in directional solidification of Ni-base superalloys. The study allows to derive the preferred locations of stray grains formation and the role played by the most affecting factors: (i) geometrical: angle of primary grain dendrites with withdrawal direction and orientation of the primary grain with respect to the side walls, responsible for the formation of volumes where the stray grain undercooling is lower than the undercooling of the columnar dendrite tip; (ii) process and alloy: thermal gradient ahead to the solidification front and alloy composition, influencing the columnar dendrite tip undercooling; (iii) wettability of foreign substrates, on which the stray grain undercooling strongly depends.

Active RFID Indoor Location System Based on RSSI Ranging Correction

2013 ◽  
Vol 677 ◽  
pp. 449-454 ◽  
Author(s):  
Qing Bin Meng ◽  
Lan Ju ◽  
Jie Jin ◽  
Wei Xiang Li
Keyword(s):  
High Precision ◽  
Environmental Parameters ◽  
Statistical Calculation ◽  
Average Deviation ◽  
Active Rfid ◽  
Indoor Location ◽  
Location System ◽  
Statistical Experiments ◽  
Location Algorithm

For indoor location, an active RFID indoor location system is designed. The system is designed and implemented by using a RSSI-based ranging technology location algorithm. In this article, the author amended the RSSI ranging equation, proposed and implemented a way to extract and estimate the environmental parameters of specific application scenarios, and improved the accuracy of the RSSI ranging. After many statistical experiments, the results show that the system’s deviation can reach 10cm on the diagonal of the region, and about 30cm on the edge. Through statistical calculation, the average deviation of system position is about 10.6cm, which is a good location system of high precision. When implemented for different applications, this system has the advantages of simplicity and adaptability.

Instrument-related geometrical factors affecting the intensity in XPS and ARXPS experiments

2011 ◽  
Vol 184 (8-10) ◽  
pp. 487-500 ◽  
Author(s):  
A. Herrera-Gomez ◽  
F.S. Aguirre-Tostado ◽  
P.G. Mani-Gonzalez ◽  
M. Vazquez-Lepe ◽  
A. Sanchez-Martinez ◽  
...  
Keyword(s):  
Factors Affecting ◽  
Geometrical Factors
Sign in / Sign up

Export Citation Format

Share Document