Astigmatism correction of convex aspheres using the subaperture stitching Hindle test

2022 ◽  
Author(s):  
Goeun Kim ◽  
In-Ung Song ◽  
Hagyong Kihm ◽  
Ho-Soon Yang
Keyword(s):  
Measurement Data ◽  
Correction Method ◽  
Test Surface ◽  
Test Results ◽  
Third Order ◽  
Error Sources ◽  
Surface Error ◽  
Astigmatism Correction ◽  
Subaperture Stitching ◽  
System Errors

Abstract We propose an astigmatism correction method for the subaperture stitching Hindle test to measure hyperbolic convex aspheres. Astigmatic wavefront errors arise from misaligned Hindle setups, mechanical runout errors of the rotational motion for stitching, and the surface error of the target itself. Because these errors are combined, they cannot be separated in the conventional subaperture stitching Hindle tests. We exploited the rotational periodicity of each error to distinguish the surface figure error from other astigmatic error sources and rectified the Hindle test results with a third-order astigmatism. Using the subaperture stitching Hindle test, we averaged two sets of measurement data with a 180° rotational phase difference between them to calculate the astigmatic surface error. The proposed method was verified experimentally by comparing it with the results from a commercial stitching interferometer from QED Technologies; only subnanometer differences in the root-mean-square values were obtained. Therefore, the proposed method calibrated the system errors from the test surface wedge and the rotational decenter easily, thereby reducing the mechanical costs and alignment efforts and making it more accessible than a sophisticated mechanism.

scholarly journals Load characteristics of three-plunger pumps for spray seawater fire-fighting

2020 ◽  
pp. 142-146
Author(s):  
В.А. Наумов ◽  
Н.Л. Великанов ◽  
А.В. Тришина
Keyword(s):  
Satisfactory Agreement ◽  
Test Data ◽  
High Efficiency ◽  
Measurement Data ◽  
Fire Fighting ◽  
Test Results ◽  
Hydraulic Characteristics ◽  
Fire Extinguishing ◽  
Load Characteristics ◽  
Low Pressures

Цель статьи – получить эмпирические зависимости для характеристик трехплунжерных противопожарных насосов (ТПН), необходимые для автоматизации расчетов систем тушения пожаров на судах с применением распыленной морской воды. Задачи исследования: проверка непротиворечивости данных испытаний; определение расчетных зависимостей производительности ТПН, к.п.д., затраченной мощности от давления. Проведенный анализ результатов испытаний ТПН подтвердил возможность использования предложенных зависимостей в инженерных расчетах. Данные измерений удовлетворительно согласуются с результатами расчетов, за исключением к.п.д. Отклонение экспериментальных точек от эмпирических зависимостей, скорее всего, связано с занижением значений затраченной мощности на испытаниях при небольших давлениях. Предложено для оценки к.п.д. использовать ранее полученную типовую зависимость. Построены графики для характеристик насоса NP25/41-170S. Пример расчета рабочей точки насосной установки с использованием приближенной гидравлической характеристики водяной пожарной системы судна показал высокую эффективность предложенных методик. The purpose of the article is to obtain empirical dependences for the characteristics of three-plunger fire-fighting pumps (TFP), which are necessary for automating calculations of fire extinguishing systems on ships using sprayed seawater. Research objectives: checking the consistency of test data; determining the calculated dependences of the TFP performance, efficiency, power expended on pressure. The analysis of the TFP test results confirmed the possibility of using the proposed dependencies in engineering calculations. The measurement data are in satisfactory agreement with the results of calculations, with the exception of efficiency. The deviation of experimental points from the empirical dependences is most likely due to an underestimation of the power consumed during tests at low pressures. It is proposed to use the previously obtained typical dependence to estimate the efficiency. Graphs are plotted for the characteristics of the NP25/41-170S pump. An example of calculating the working point of a pumping unit using the approximate hydraulic characteristics of the ship's water fire system showed the high efficiency of the proposed methods.

scholarly journals Time interval measurement module implemented in SoC FPGA device

2016 ◽  
Vol 62 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Grzegorz Grzęda ◽  
Ryszard Szplet
Keyword(s):  
Mass Measurement ◽  
Measurement Data ◽  
Measurement Instrument ◽  
General Concept ◽  
Time Interval ◽  
Processing Unit ◽  
Test Results ◽  
Interval Measurement ◽  
Time Interval Measurement ◽  
On Chip

Abstract We presents the design and test results of a picosecond-precision time interval measurement module, integrated as a System-on-Chip in an FPGA device. Implementing a complete measurement instrument of a high precision in one chip with the processing unit gives an opportunity to cut down the size of the final product and to lower its cost. Such approach challenges the constructor with several design issues, like reduction of voltage noise, propagating through power lines common for the instrument and processing unit, or establishing buses efficient enough to transport mass measurement data. The general concept of the system, design hierarchy, detailed hardware and software solutions are presented in this article. Also, system test results are depicted with comparison to traditional ways of building a measurement instrument.

Error Recovery System Encoder/Decoder Method and VHDL Design for Saving Memory of Embedded System

2011 ◽  
Vol 110-116 ◽  
pp. 4985-4991
Author(s):  
Byung Joon Kim ◽  
Rae Cho Sung ◽  
Sung Ho Jin
Keyword(s):  
Embedded System ◽  
Error Correction ◽  
Recovery Process ◽  
Error Recovery ◽  
Correction Method ◽  
Memory Space ◽  
Rs Code ◽  
Error Correction Method ◽  
Recovery System ◽  
System Errors

Unexpected errors may occur in any embedded systems. An error correction circuitry is used to prevent system errors. Parity bits generated from an encoder are needed to perform an error recovery process. Therefore, to be stored in the memory space should be added. In this paper, Parity bits to be stored without a memory space that can be used to error correction circuitry are proposed. The proposed method was designed in VHDL. The proposed design used the Reed-Solomon (RS) code of an error correction method. Then, 8 bits of information symbols and a symbol error correcting RS code were designed based on the design.

scholarly journals Nonintrusive Appliance Load Monitoring: An Overview, Laboratory Test Results and Research Directions

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3621 ◽  
Author(s):  
Augustyn Wójcik ◽  
Robert Łukaszewski ◽  
Ryszard Kowalik ◽  
Wiesław Winiecki
Keyword(s):  
Smart Home ◽  
State Of The Art ◽  
Measurement Data ◽  
Electricity Consumption ◽  
Identification Accuracy ◽  
Test Results ◽  
Research Directions ◽  
Laboratory Test Results ◽  
New Directions ◽  
Load Monitoring

Nonintrusive appliance load monitoring (NIALM) allows disaggregation of total electricity consumption into particular appliances in domestic or industrial environments. NIALM systems operation is based on processing of electrical signals acquired at one point of a monitored area. The main objective of this paper was to present the state-of-the-art in NIALM technologies for the smart home. This paper focuses on sensors and measurement methods. Different intelligent algorithms for processing signals have been presented. Identification accuracy for an actual set of appliances has been compared. This article depicts the architecture of a unique NIALM laboratory, presented in detail. Results of developed NIALM methods exploiting different measurement data are discussed and compared to known methods. New directions of NIALM research are proposed.

Study on Correction Method of Subgrade Modulus Based on FWD

2013 ◽  
Vol 579-580 ◽  
pp. 862-865
Author(s):  
Xiao Hua Luo ◽  
Qing Yang ◽  
Xin Qiu
Keyword(s):  
Resilient Modulus ◽  
Implementation Process ◽  
Correction Method ◽  
Deformation Analysis ◽  
Test Results ◽  
Moisture Condition ◽  
Back Calculation ◽  
The Mean ◽  
Subgrade Modulus ◽  
New Perspective

In order to calibrate subgrade back calculation modulus, the correction method of subgrade back calculation modulus was put forward based on theoretical analysis and indoor/outdoor experiments, and the detailed implementation process was analyzed combined the latest results of subgrade dynamic modulus and subgrade moisture forecast. The results show that the equivalent resilient modulus of subgrade simultaneously consider subgrade material moisture condition and stress dependency and the forecast equation has higher correlation. The ratio of the loading plate test results to the predicted results ranges from 0.25 to 0.4 and the mean is 0.32, which conforms to the requirements of AASHTO normal value. Utilizing the scale factor 0.65 to calibrate subgrade back calculation modulus is viable and validated. The results provides a new perspective and approach for deformation analysis of subgrade structure. As well, the established method makes up the defect that can't reflect the effect of moisture and stress on equivalent resilient modulus of subgrade.

scholarly journals Experimental Investigation of an Automotive Magnetorheological Shock Absorber

2017 ◽  
Vol 11 (4) ◽  
pp. 253-259
Author(s):  
Łukasz Jastrzębski ◽  
Bogdan Sapiński
Keyword(s):  
Shock Absorber ◽  
Measurement Data ◽  
Test Results ◽  
Experimental Examination ◽  
Piston Velocity ◽  
Testing Program ◽  
Technical Data ◽  
Piston Displacement ◽  
Operating Current ◽  
Set Up

AbstractThe study summarises the experimental examination of an automotive magnetorheological (MR) shock absorber under electrical and mechanical excitations, investigates its current and force responses and the energy dissipation in the system. The aim of experiments was to acquire measurement data that allows in next step of the research program to engineer an energy harvesting device for the absorber. The work covers basic technical data of the absorber, description of the experimental set-up, scenario of testing program and test results of the device. Of particular importance is the influence the operating current, piston displacement amplitude and piston velocity have on the absorber’s response.

Influence of Strain Gauge Bonding-Process on Measurement Data Accuracy of Composite Material Structure

2014 ◽  
Vol 910 ◽  
pp. 132-136
Author(s):  
Jia Zuo ◽  
Jian Feng Zhang
Keyword(s):  
Strain Gauge ◽  
Measurement Data ◽  
Surface Cleaning ◽  
Strength Test ◽  
Data Accuracy ◽  
Material Structure ◽  
Test Results ◽  
Bonding Agents ◽  
Cleaning Agents ◽  
Measured Strain

With the extensive application of composite materials in aircraft structure, effect of the installing process of strain gauge on the strain measuring results of composite structure need to be researched experimentally. In this paper, the composite (T700/LT-03A) was selected to made specimens, and the different grinding manners, surface cleaning agents and bonding agents were adopted respectively as one of strain gauge installing processes. In order to identify influence of the different installing processes on the measuring data accuracy, measured strain data repeatability, linearity and characteristics of measured value oscillation are served as test standard. The compared test results show that the strain installing processes adopted in strength test on traditional metal also apply to the composite (T700/LT-03A) structures strength test.

The Research of Straight Pipe Viscometer

2013 ◽  
Vol 694-697 ◽  
pp. 976-980
Author(s):  
En Ping Zhang ◽  
Bao Shuang Liu ◽  
Xi Min Liu ◽  
Ming Jian Huang ◽  
Hong Wei Ren
Keyword(s):  
Signal Processing ◽  
Data Acquisition ◽  
Measurement Data ◽  
Test Results ◽  
Single Chip ◽  
Working Process ◽  
Straight Pipe ◽  
Pressure Transmitter ◽  
Drive Circuit ◽  
Rotary Viscometer

A straight pipe viscometer is proposed, which consists of the measuring sub-system and the data-acquisition and signal processing sub-system. The measuring sub-system include straight pipe, pressure transmitter, Coriolis flow-meter and slurry bump, and the data-acquisition and signal processing sub-system include single-chip processor, A/D converter, digital display, serial output port, drive circuit and so on. The measuring principle and working process of the straight pipe viscometer are analyzed. The measurement data and results are given and compared with test results of rotary viscometer in the same test conditions. The measuring accuracy is 3% at 5-150mPas, and the online measurement of viscosity is implemented.

scholarly journals Model Tests for Shallow-Water Ship Maneuverability in Three Gorges Reservoir

2015 ◽  
Vol 22 (s1) ◽  
pp. 136-140
Author(s):  
Chuang Cai ◽  
Xinyong Cai ◽  
Yi Li
Keyword(s):  
Shallow Water ◽  
Scale Effect ◽  
Three Gorges Reservoir ◽  
Correction Method ◽  
Model Tests ◽  
Influential Factors ◽  
Three Gorges ◽  
Test Results ◽  
Experimental Basis ◽  
Ship Maneuverability

Abstract This paper conducts calibration tests on the shallow-water maneuverability of 1:100 ship models for the typical navigation fleets in Three Gorges Reservoir. Major influential factors for the maneuverability similitude between models and prototypes and for scale effect were identified. A correction method for model scale was also established through model tests. Test results indicate that, by correcting the model scales of various fleets based on scale effect, the maneuverability indexes K’ (dimensionless of K) and T’ (dimensionless of T) of ship models are suitable for shallow-water tests, and properly reflect the maneuvering characteristics of prototypes. The findings provide an experimental basis for the navigation safety in Three Gorges Reservoir.

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