scholarly journals Study of the Effect of Intake Layout on the Wavefront in a Beam Expanding System of a Telescope

2020 ◽  
Vol 10 (10) ◽  
pp. 3643
Author(s):  
Qingpeng Zhang ◽  
Yi Tan ◽  
Ge Ren ◽  
Tao Tang
Keyword(s):  
High Reliability ◽  
Wavefront Aberration ◽  
Flow State ◽  
Analysis Method ◽  
Smooth Flow ◽  
Main Disadvantage ◽  
The Matrix ◽  
Calculation Results ◽  
Ray Tracing Simulation ◽  
Small Holes

The main disadvantage of windowless beam expansion systems is that they cannot achieve a good sealing effect. Turbulence and impurities in the environment can easily affect the imaging and primary mirror. Thus, in this study, a matrix of small holes was introduced for inflation to form a stable and smooth flow inside the system to avoid these disadvantages. In order to study the layout of the matrix, the flow state of the model was analysed, and the Lorentz–Lorenz formula and Barron gradient operator were used for ray tracing. Simulation results show that when the matrix of small holes is arranged in 16 rows with 360 holes in each row, inflation has a lesser effect on the wavefront aberration of the system. Moreover, the root mean square (RMS) of wavefront aberration was only 0.077 μm, which was superior to the other layouts considered. Experimental results show that the RMS was 0.08 μm in this state, which is consistent with the analysis. This indicates that this analysis method can meet actual work needs. The calculation methods and calculation results have high reliability and, thus, can be also used in similar situations.

scholarly journals Dilution of QuEChERS Extracts Without Cleanup Improves Results in the UHPLC-MS/MS Multiresidue Analysis of Pesticides in Tomato

2021 ◽  
Author(s):  
Fabiane M. Stringhini ◽  
Lucila C. Ribeiro ◽  
Graziela I. Rocha ◽  
Juliana D. de B. Kuntz ◽  
Renato Zanella ◽  
...  
Keyword(s):  
Matrix Effect ◽  
Practical Method ◽  
Analysis Method ◽  
Multiresidue Analysis ◽  
Limit Of Quantification ◽  
Chromatography Tandem Mass Spectrometry ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Ultrahigh Performance Liquid Chromatography ◽  
Positive Results

AbstractTomato is well-known to be one of the most cultivated and consumed vegetables worldwide and frequently contain pesticide residues. Therefore, a simple multiresidue method was established and validated to determine 129 pesticides and metabolites in tomato samples using a modified acetate QuEChERS without cleanup for sample preparation and determination by ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Dilution of the raw extract in different proportions of mobile phase was evaluated and a dilution of 10 times presented adequate results improving analysis performance while minimizing the matrix effect. Validation performed according to SANTE guideline presented satisfactory results. Practical method limit of quantification was 0.01 mg kg−1 for most compounds. Recoveries between 70 and 120% with precision ≤ 20% were found for most compounds and spike levels evaluated. Matrix effect results were not significant for most part of compounds. Method proved to be simple, robust, and effective to be applied in routine analysis. Method applicability was performed by analysis of samples commercialized in Brazil and positive results were found demonstrating the importance of the proposed method.

scholarly journals Geographic Information Systems Application to Drought Distribution Identification with Standardized Precipitation Index (SPI) Method in Trenggalek Regency

2021 ◽  
Vol 5 (2) ◽  
pp. 266-278
Author(s):  
Aditya Utama ◽  
Mohammad Pramono Hadi ◽  
Emilya Nurjani
Keyword(s):  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Analysis Method ◽  
A Value ◽  
Distance Weighted ◽  
Calculation Results ◽  
Negative Impacts ◽  
The Standardized Precipitation Index ◽  
Inverse Distance ◽  
Rain Data

The widespread drought area in Trenggalek Regency in 2019 needs to be analyzed to reduce negative impacts and as a monitoring tool to anticipate future drought events. The Standardized Precipitation Index (SPI) is a drought analysis method by calculating the rainwater deficit at various time scales used to identify the distribution of drought in Trenggalek Regency. This study using rain data on 13 rain stations for the period 1990-2019 and agricultural production data for 2019. The calculation results show that the highest SPI value occurred in March at the highly wet level with a value of 2.11. The lowest SPI value occurred in May at the extremely dry level with a value of -2.31. The results are then mapped using ArcGIS with the Inverse Distance Weighted (IDW) method to identify the spatial distribution of drought.

scholarly journals An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing

2017 ◽  
Vol 17 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. Borowiecka-Jamrozek ◽  
J. Lachowski
Keyword(s):  
Elastic Energy ◽  
Synthetic Diamond ◽  
Computer Modelling ◽  
Diamond Particle ◽  
Metallic Matrix ◽  
Mechanical Parameters ◽  
Powder Mixtures ◽  
The Matrix ◽  
Calculation Results ◽  
Abaqus Software

Abstract This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.

Calculation methods of bridge deck for prestressed short rib T-beam bridges

2020 ◽  
pp. 1-13
Author(s):  
Sijia Wang ◽  
Tianlai Yu
Keyword(s):  
Finite Element ◽  
Bridge Deck ◽  
Mechanical Performance ◽  
Test Results ◽  
Analysis Method ◽  
Slab Method ◽  
Element Analysis ◽  
Calculation Results ◽  
Beam Bridge ◽  
T Beam

Because of the low height of the prestressed short rib T-beam bridge and the poor torsion resistance of the main beam, the positive moment in the middle span of the bridge deck will increase correspondingly compared with the normal rib beam bridge. At present, there is little research on the calculation method of the bridge deck of the prestressed short rib T-beam bridge. In this paper, the space finite element method and the continuous one-way slab method are used to calculate the forces on the bridge deck, based on the space finite element method, a finite element elastic supported continuous beam method is proposed to calculate the forces on the bridge deck. By comparing the calculation results of the three methods with the test results, the reasonable calculation method of the bridge deck is studied. The results show that the spatial finite element analysis method can simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge well, the stress calculation results are consistent with the test results, and the calculation accuracy is high, which can be used in the actual engineering design; The finite element analysis method of elastic support continuous beam can also simulate the mechanical performance of the deck of the bridge of the prestressed short rib T-beam bridge. The concept of the method is clear, the calculation is convenient, and it is more suitable for the application of engineering design; The calculation results of the continuous one-way slab method are too large to be safe for design.

Modal Analysis of Multi-Stepped Distributed-Parameter Rotor-Bearing Systems Using Exact Dynamic Elements

2001 ◽  
Vol 123 (3) ◽  
pp. 401-403 ◽  
Author(s):  
Seong-Wook Hong ◽  
Jong-Heuck Park
Keyword(s):  
Modal Analysis ◽  
Closed Form ◽  
Complete Analysis ◽  
Distributed Parameter ◽  
Analysis Method ◽  
Closed Form Solutions ◽  
Analysis Scheme ◽  
Rotor Bearing ◽  
The Matrix ◽  
Transcendental Functions

Although the exact dynamic elements have been suggested by the authors [1] and proved to be useful for the dynamic analysis of distributed-parameter rotor-bearing systems, difficulty remains in computation because of the presence of transcendental functions in the matrix. This paper proposes a complete analysis scheme for the exact dynamic elements, a generalized modal analysis method, to obtain exact and closed form solutions of time and frequency domain responses for multi-stepped distributed-parameter rotor-bearing systems. A numerical example is provided for validating the proposed method.

scholarly journals Numerical Thermal Analysis and 2-D CFD Evaluation Model for An Ideal Cryogenic Regenerator

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 361 ◽  
Author(s):  
Natheer Almtireen ◽  
Jürgen J. Brandner ◽  
Jan G. Korvink
Keyword(s):  
High Reliability ◽  
Low Cost ◽  
Evaluation Model ◽  
Volumetric Flow Rate ◽  
Cooling Capacity ◽  
Heating And Cooling ◽  
The Matrix ◽  
Overall Performance ◽  
Application Requirements ◽  
Vital Element

Regenerative cryocoolers such as Stirling, Gifford–McMahon, and pulse tube cryocoolers possess great merits such as small size, low cost, high reliability, and good cooling capacity. These merits led them to meet many IR and superconducting based application requirements. The regenerator is a vital element in these closed-cycle cryocoolers, but the overall performance depends strongly on the effectiveness of the regenerator. This paper presents a one-dimensional numerical analysis for the idealized thermal equations of the matrix and the working gas inside the regenerator. The algorithm predicts the temperature profiles for the gas during the heating and cooling periods, along with the matrix nodal temperatures. It examines the effect of the regenerator’s length and diameter, the matrix’s geometric parameters, the number of heat transfer units, and the volumetric flow rate, on the performance of an ideal regenerator. This paper proposes a 2D axisymmetric CFD model to evaluate the ideal regenerator model and to validate its findings.

Building the Simple Model of Bridge Reinforced Shallow Foundation

2014 ◽  
Vol 1079-1080 ◽  
pp. 127-130
Author(s):  
Hai Zhang ◽  
Yuan Cheng Ni ◽  
Li Jiao
Keyword(s):  
Simple Model ◽  
Reference Value ◽  
Shallow Foundation ◽  
Actual Situation ◽  
Analysis Method ◽  
Substantial Agreement ◽  
Safety Requirement ◽  
Finite Element Software ◽  
Calculation Results ◽  
The Ideal

In order to calculate the shallow foundation for moreappropriate, the paperbuildinga simplemodel in line with the actual situation of reinforced shallow foundation andcalculates, thereby improves the existing analysis method. By analyzing themodel of shallow foundation reinforced by supplementary pile, the paper getsthe method for the new model, and combined with the specificexample. Then we compare theresult between the simple model calculation and theanalysis of finite element software Midas/GTS. The analysis of specific exampleshows that, the calculation results of this new simple model and finite elementsoftware are in substantial agreement, and satisfied the safety requirement,and achieves the ideal target.It has a certain practical and reference value,because itcan be quickly and conveniently to calculate the bridge shallow foundation.

The Investigation of Stability Analysis of Tube and Coupler Scaffold

2012 ◽  
Vol 594-597 ◽  
pp. 730-733 ◽  
Author(s):  
Hua Zhi Li ◽  
Zhe Liu ◽  
Jia Yong Miao
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
Empirical Method ◽  
Analysis Method ◽  
Ultimate Load Capacity ◽  
Calculation Results ◽  
Impacting Factors ◽  
The Stability ◽  
High Load Capacity ◽  
Semi Empirical

The tube and coupled scaffold is widely used in the construction of building, bridge, sports stadium etc, due to the advantage of easily assembling, high load capacity and good overall stiffness. However as a very important temporary structure in the construction, the semi-empirical method has been used for the calculation of ultimate load capacity (ULC), whether the calculation results are acceptable is not given too much attention. To ascertain the safety of using process, the FEM code-Midas is used to investigate and compare the stability and ultimate load analysis method of scaffold, and the impacting factors, such as the span, step distance, height, and width of scaffold, are discussed, the varying process and trend is described in this paper.

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