scholarly journals Application of Latitude Stripe Division in Satellite Constellation Coverage to Ground

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Maocai Wang ◽  
Xin Luo ◽  
Guangming Dai ◽  
Xiaoyu Chen
Keyword(s):  
Orbital Period ◽  
High Efficiency ◽  
Classical Method ◽  
Grid Point ◽  
Spherical Geometry ◽  
Optimized Design ◽  
Target Region ◽  
Satellite Constellation ◽  
Orbital Periods ◽  
The Relationship

Grid point technique is a classical method in computing satellite constellation coverage to the ground regions. Aiming at improving the low computational efficiency of the conventional method, a method using latitude stripe division is proposed, which has high efficiency, and we name it latitude stripe method. After dividing the target region into several latitude stripes, the coverage status of each latitude stripe is computed by means of the spherical geometry relationship in the first orbital period. The longitude coverage intervals in the remaining orbital periods are computed by sliding the coverage status in the first orbital period. Based on this method, the instantaneous and cumulative coverage in simulation time can be calculated more efficiently. As well, the relationship between the cumulative coverage and altitude can be computed fast by this method, which could be used in the optimized design of repeating sun-synchronous orbits. The comparison between the conventional grid point method and the latitude stripe method shows that the latitude stripe method has high efficiency and accuracy. Through various case studies, the optimization in repeating sun-synchronous orbits design is successfully represented.

scholarly journals Improvement Effect of Green Remodeling and Building Value Assessment Criteria for Aging Public Buildings

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1200
Author(s):  
Yong-Joon Jun ◽  
Seung-ho Ahn ◽  
Kyung-Soon Park
Keyword(s):  
High Efficiency ◽  
Energy Performance ◽  
Operating Conditions ◽  
Energy Usage ◽  
Public Buildings ◽  
Value Judgment ◽  
Relationship Analysis ◽  
Improvement Effect ◽  
The Relationship ◽  
Usage Data

The Green Remodeling Project under South Korea’s Green New Deal policy is a government-led project intended to strengthen the performance sector directly correlated with energy performance among various elements of improvement applicable to building remodeling by replacing insulation materials, introducing new and renewable energy, introducing high-efficiency equipment, etc., with public buildings taking the lead in green remodeling in order to induce energy efficiency enhancement in private buildings. However, there is an ongoing policy that involves the application of a fragmentary value judgment criterion, i.e., whether to apply technical elements confined to the enhancement of the energy performance of target buildings and the prediction of improvement effects according thereto, thus resulting in the phenomenon of another important value criterion for green remodeling, i.e., the enhancement of the occupant (user) comfort performance of target buildings as one of its purposes, being neglected instead. In order to accurately grasp the current status of these problems and to promote ‘expansion of the value judgment criteria for green remodeling’ as an alternative, this study collected energy usage data of buildings actually used by public institutions and then conducted a total analysis. After that, the characteristics of energy usage were analyzed for each of the groups of buildings classified by year of completion, thereby carrying out an analysis of the correlation between the non-architectural elements affecting the actual energy usage and the actual energy usage data. The correlation between the improvement performance of each technical element and the actual improvement effect was also analyzed, thereby ascertaining the relationship between the direction of major policy strategies and the actual energy usage. As a result of the relationship analysis, it was confirmed that the actual energy usage is more affected by the operating conditions of the relevant building than the application of individual strategic elements such as the performance of the envelope insulation and the performance of the high-efficiency system. In addition, it was also confirmed that the usage of public buildings does not increase in proportion to their aging. The primary goal of reducing energy usage in target buildings can be achieved if public sector (government)-led green remodeling is pushed ahead with in accordance with biased value judgment criteria, just as in the case of a campaign to refrain from operating cooling facilities in aging public buildings. However, it was possible to grasp through the progress of this study that the remodeling may also result in the deterioration of environmental comfort and stability, such as the numerical value of the indoor thermal environment. The results of this study have the significance of providing basic data for pushing ahead with a green remodeling policy in which the value judgment criteria for aging existing public buildings are more expanded, and it is necessary to continue research in such a direction that the quantitative purpose of green remodeling, which is to reduce energy usage in aging public buildings, and its qualitative purpose, which is to enhance their environmental performance for occupants’ comfort, can be mutually balanced and secured at the same time.

scholarly journals Tidally induced stellar oscillations: converting modelled oscillations excited by hot Jupiters into observables

2020 ◽  
Vol 500 (2) ◽  
pp. 2711-2731
Author(s):  
Andrew Bunting ◽  
Caroline Terquem
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Planetary Systems ◽  
Velocity Signal ◽  
Convective Flux ◽  
Hot Jupiters ◽  
Stellar Oscillations ◽  
Orbital Periods ◽  
Hot Jupiter

ABSTRACT We calculate the conversion from non-adiabatic, non-radial oscillations tidally induced by a hot Jupiter on a star to observable spectroscopic and photometric signals. Models with both frozen convection and an approximation for a perturbation to the convective flux are discussed. Observables are calculated for some real planetary systems to give specific predictions. The photometric signal is predicted to be proportional to the inverse square of the orbital period, P−2, as in the equilibrium tide approximation. However, the radial velocity signal is predicted to be proportional to P−1, and is therefore much larger at long orbital periods than the signal corresponding to the equilibrium tide approximation, which is proportional to P−3. The prospects for detecting these oscillations and the implications for the detection and characterization of planets are discussed.

scholarly journals A tale of two periods: determination of the orbital ephemeris of the super-Eddington pulsar NGC 7793 P13

2018 ◽  
Vol 616 ◽  
pp. A186 ◽  
Author(s):  
F. Fürst ◽  
D. J. Walton ◽  
M. Heida ◽  
F. A. Harrison ◽  
D. Barret ◽  
...  
Keyword(s):  
Accretion Disk ◽  
Orbital Period ◽  
Timing Analysis ◽  
X Ray ◽  
System Parameters ◽  
Orbital Resonance ◽  
Photometric Period ◽  
Orbital Periods ◽  
Analyze Data

We present a timing analysis of multiple XMM-Newton and NuSTAR observations of the ultra-luminous pulsar NGC 7793 P13 spread over its 65 d variability period. We use the measured pulse periods to determine the orbital ephemeris, confirm a long orbital period with Porb = 63.9+0.5−0.6 d, and find an eccentricity of e ≤ 0.15. The orbital signature is imprinted on top of a secular spin-up, which seems to get faster as the source becomes brighter. We also analyze data from dense monitoring of the source with Swift and find an optical photometric period of 63.9 ± 0.5 d and an X-ray flux period of 66.8 ± 0.4 d. The optical period is consistent with the orbital period, while the X-ray flux period is significantly longer. We discuss possible reasons for this discrepancy, which could be due to a super-orbital period caused by a precessing accretion disk or an orbital resonance. We put the orbital period of P13 into context with the orbital periods implied for two other ultra-luminous pulsars, M82 X-2 and NGC 5907 ULX, and discuss possible implications for the system parameters.

scholarly journals The Relation between Spin and Orbital Periods in HMXBs

2003 ◽  
Vol 214 ◽  
pp. 215-217
Author(s):  
Q. Z. Liu ◽  
X. D. Li ◽  
D. M. Wei
Keyword(s):  
Magnetic Fields ◽  
Orbital Period ◽  
Critical Line ◽  
High Mass ◽  
Orbital Eccentricity ◽  
X Ray ◽  
Spin Period ◽  
Orbital Periods ◽  
X Ray Binaries

The relation between the spin period (Ps) and the orbital period (Po) in high-mass X-ray binaries (HMXBs) is investigated. In order for Be/X-ray binaries to locate above the critical line of observable X-ray emission due to accretion, it is necessary for an intermediate orbital eccentricity to be introduced. We suggest that some peculiar systems in the Po − Ps diagram are caused by their peculiar magnetic fields.

scholarly journals Modeling of texture of the surface of collector plates

2019 ◽  
Vol 3 (122) ◽  
pp. 59-71
Author(s):  
Volodymyr Serhiiovych Hryshyn ◽  
Serhii Oleksiiovych Abramov
Keyword(s):  
High Efficiency ◽  
Statistical Simulation ◽  
Optimal Choice ◽  
Technological Parameters ◽  
Resource Saving ◽  
Technological Processes ◽  
Air Jet ◽  
Concrete Production ◽  
High Efficient ◽  
The Relationship

Technological possibilities of jet processing cause increased attention to the study of the regularities of the process. The main interest for practice is the establishment of the kind of dependencies between technological parameters (abrasive particles size, particle speed, concentration, compressed air pressure, attack angle, physical and mechanical properties of particles and surface to be treated) and initial process parameters (roughness of the treated surface, removal rates of the metal and libel). That, in turn, determines the necessity of optimal choice of the values of technological parameters in the conditions of a concrete production situation. The basic regularities can be established as a result of regression analysis of experimental data. However, the use of the resulting laws is limited to the complexity of the process and relatively narrow areas of changing the parameters of the experiment.The purpose of the work is to determine the factors that determine the formation of a microrelief in the area of the abrasive air jet, the relationship between them and the degree of their effect on the intensity of the formation of a microrelief; formation of a model of finishing treatment of collector plates, creation of theoretical bases and methodology of designing high-efficient resource-saving technological processes of production of motor collectors of electric machines.Analysis of recent research and publications. The following contributions were made to the development of the theory of modeling of the inkjet-abrasive surface treatment: Volovetsky O.E., Denysyuk V.Yu., Kharchik M.M., Buts BP, Andilahi A.A., Novikov FV, Gordeyev AI, Urbanyuk Ye.A., Silin R.S. and other.The most universal approach based on determining the search dependencies and solving the problem of optimizing the technological parameters of the processing process as a result of statistical simulation, namely the ability to control the input parameters before the start of the model or in the process of work - one of the key benefits of using simulation modeling for the analysis of systems and processes. This allows you to determine the optimal parameters, which maximize the efficiency of the processes, determine the relationship between the input and output parameters.The paper considers: creation of theoretical bases and methodology of designing high-efficiency resource-saving technological processes of production of motor collectors of electric machines; the process of formation of microrelief of collector plates in the area of the abrasive air jet, the relationship between the factors and the degree of their influence on the intensity of formation. The formation of a model of finishing treatment of collector plates treated with silicon carbide (black) was determined.Prospects for further research are the improvement of the technological process of obtaining collector nodes on the possibilities of implementation.

scholarly journals Recycling Heat Losses of an Oil-Immersed Transformer: Feasibility Study

2021 ◽  
Vol 21 (1) ◽  
pp. 48-54
Keyword(s):  
High Efficiency ◽  
Power Transformer ◽  
Heat Losses ◽  
Power Transformers ◽  
Passive Mode ◽  
Active Mode ◽  
Short Circuits ◽  
Definition Of ◽  
The Relationship ◽  
Novel Design

The paper investigates the feasibility of adding a liquid heater to an oil-immersed transformer. It proves that design the high efficiency of power transformers, losses due to idling and short circuits are substantial and are scattered in the environment as heat. The paper proposes a novel design that implements a liquid (coolant) heater to enable the unit not only to convert electricity, but also to generate heat. In order to analyze the feasibility of such heat recycling, the authors have developed an equivalent thermal circuit and a mathematical model thereof. Said heater can operate in two modes. In the passive mode, the coolant it contains only absorbs the heat emitted (lost) by the power transformer. In the active mode, it also receives the heat emitted due to the passage of electric current through the pipes of the heater. The paper further introduces the definition of heater efficiency. Studies have shown that up to 50 % of transformer heat losses can be recycled by heating the coolant in the heater. The paper presents the relationship between utilized heat and transformer losses, as well as heater efficiency as a function of coolant flow rate. The heater efficiency exceeds 90 % in the active mode.

scholarly journals Binocular stereovision omnidirectional motion handling robot

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092685
Author(s):  
Bo Tang ◽  
Li Jiang
Keyword(s):  
Real Time ◽  
High Efficiency ◽  
Recognition Rate ◽  
Three Dimensional ◽  
Image Feature ◽  
Software Framework ◽  
Matching Algorithm ◽  
Speeded Up Robust Features ◽  
Binocular Stereovision ◽  
The Relationship

Binocular stereovision has become one of the development trends of machine vision and has been widely used in robot recognition and positioning. However, the current research on omnidirectional motion handling robots at home and abroad is too limited, and many problems cannot be solved well, such as single operating systems, complex algorithms, and low recognition rates. To make a high-efficiency handling robot with high recognition rate, this article studies the problem of robot image feature extraction and matching and proposes an improved speeded up robust features (SURF) algorithm that combines the advantages of both SURF and Binary Robust Independent Elementary Features. The algorithm greatly simplifies the complexity of the algorithm. Experiments show that the improved algorithm greatly improves the speed of matching and ensures the real-time and robustness of the algorithm. In this article, the problem of positioning the target workpiece of the robot is studied. The three-dimensional (3-D) reconstruction of the target workpiece position is performed to obtain the 3-D coordinates of the target workpiece position, thereby completing the positioning work. This article designs a software framework for real-time 3-D object reconstruction. A Bayesian-based matching algorithm combined with Delaunay triangulation is used to obtain the relationship between supported and nonsupported points, and 3-D reconstruction of target objects from sparse to dense matches is achieved.

scholarly journals Eclipse timing variation of GK Vir: evidence of a possible Jupiter-like planet in a circumbinary orbit

2020 ◽  
Vol 497 (3) ◽  
pp. 4022-4029
Author(s):  
L A Almeida ◽  
E S Pereira ◽  
G M Borges ◽  
A Damineli ◽  
T A Michtchenko ◽  
...  
Keyword(s):  
Orbital Period ◽  
Binary Systems ◽  
Orbital Stability ◽  
Theoretical Description ◽  
Apsidal Motion ◽  
Variation Analysis ◽  
Third Body ◽  
Common Envelope ◽  
Cyclic Behaviour ◽  
Orbital Periods

ABSTRACT Eclipse timing variation analysis has become a powerful method to discover planets around binary systems. We applied this technique to investigate the eclipse times of GK Vir. This system is a post-common envelope binary with an orbital period of 8.26 h. Here, we present 10 new eclipse times obtained between 2013 and 2020. We calculated the O−C diagram using a linear ephemeris and verified a clear orbital period variation (OPV) with a cyclic behaviour. We investigated if this variation could be explained by the Applegate mechanism, the apsidal motion, or the light travel time (LTT) effect. We found that the Applegate mechanism would hardly explain the OPV with its current theoretical description. We obtained using different approaches that the apsidal motion is a less likely explanation than the LTT effect. We showed that the LTT effect with one circumbinary body is the most likely cause for the OPV, which was reinforced by the orbital stability of the third body. The LTT best solution provided an orbital period of ∼24 yr for the outer body. Under the assumption of coplanarity between the external body and the inner binary, we obtained a Jupiter-like planet around the GK Vir. In this scenario, the planet has one of the longest orbital periods, with a full observational baseline, discovered so far. However, as the observational baseline of GK Vir is smaller than twice the period found in the O−C diagram, the LTT solution must be taken as preliminary.

scholarly journals Estimation of C∗-Integral for Central Cracked Plate Under Biaxial Loading

2020 ◽  
Vol 12 (07) ◽  
pp. 2050079
Author(s):  
Yanwei Dai ◽  
Fei Qin ◽  
Yinghua Liu ◽  
Weizhe Feng ◽  
Guian Qian
Keyword(s):  
Loading Condition ◽  
Biaxial Loading ◽  
Classical Method ◽  
Creep Crack ◽  
Cracked Plate ◽  
Reference Stress ◽  
Creep Time ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

The reference stress method (RSM) is a classical method to estimate [Formula: see text]-integral of creep crack. An extended reference stress method (ERSM) is given for the central cracked plate (CCP) under biaxial loading in this paper. The applicability and verification for the proposed ERSM is given. The study finds that the solutions with the proposed ERSM agree better than those of RSM under biaxial loading condition. A theoretical form to predict the relationship of [Formula: see text]-integral between biaxial loading and uniaxial loading is discussed. Relation between [Formula: see text]-integral and creep time under biaxial loading is validated and discussed.

Protective Efficiency of Filtering Respirators

2017 ◽  
Vol 25 ◽  
pp. 88-95
Author(s):  
Sergiy Cheberiachko ◽  
Olena Yavors’ka ◽  
Olena Stolbchenko ◽  
Dmytro Radchuk
Keyword(s):  
High Efficiency ◽  
Protective Device ◽  
Protective Efficiency ◽  
Protective Devices ◽  
Respiratory Protective Devices ◽  
The Face ◽  
The Relationship ◽  
Protective Effectiveness ◽  
Penetration Coefficient

In the article the dependence of protective efficiency of the respiratory protective devices on the filter penetration coefficient and leakage of the polluted air through sealing band was established. The leakage was determined by the ratio of the filter resistance and the sealing band. The relationship between increasing the filter resistance and worsening the protective effectiveness of respiratory protective device was established. Factors that worsen the respirator quality were determined: the gaps between the face and half-mask, weak tension of the head harness. Filter parameters that will ensure high efficiency for respirators of the second protection class were established.

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