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The purpose of this paper is to introduce a weighted average method to process speed measurements from multiple magnetic sensors, which are installed on road segments. Speeds are weighted‐averaged in a fix duration time (5 minutes) for each sensor across location index of the sensor where it was installed. The proposed method is evaluated with numeric and simulation results.

Unlike traditional vehicle average speed measurements, the authors propose a weighted‐average speed measurement method of road segment, using wireless magnetic sensor nodes, which are installed on the measured road segment. Magnetic sensors offer a non‐contact vehicle detection method, and small sensors with relatively low power consumption. Using magnetic sensors, the local changes in the Earth's magnetic field caused by the presence of a moving vehicle can be measured and the vehicle's speed obtained. Next, using adaptive weighted average algorithm and space weighted algorithm in a fixed period, the weighted average travel speed of road segment can be obtained.

In current literature, there are many methods to measure vehicles' speed on road, such as image‐based, radar‐based, GPS‐based, double‐loop‐based or magnetic sensor‐based, but most of them only provide individual vehicle speed. Using probe vehicles, mean travel speed of road segment can be obtained, but it is costly on hardware and measurement, because many probe‐vehicles need to be used on roads and many measurements need to be done everyday. GPS data can be used to provide valuable travel speed data for Intelligent Transportation System (ITS). However, not every vehicle is equipped with GPS and to access ID numbers for personal cars would entail privacy problems. Mean travel speed of road segment is obtained based on statistical average speed. Generally, statistical average speed is used, which is based upon Gaussian distribution is not true in traffic systems.

By using wireless magnetic sensor nodes, vehicle instantaneous speeds are obtained in a fixed time when vehicles are passing over sensor nodes and then the adaptive weighted average speed on each sensor node location is computed based on the monitoring data from each sensor node in the fixed time. Considering different weights of each lane and road space (in the middle of the road segment or near the intersection), the proposed scheme can obtain the weighted‐average speed of the road segment.

Review of the advancements in non-contact laser sensors for much more accurate real time speed as well as length measurements. The paper aims to discuss these issues.

In-depth review of a number of applications of laser sensors.

A wide range of manufacturers in the converting industries have solved measurement problems and realized major improvements in product quality, cost of production and productivity by applying laser measurement as well as reduction in scrap.

Others with the need to make very accurate measurements of speed and length in real time may find that laser sensors may provide the answer.

An expert insight into how to solve real time speed and length measurement problems.

“WHAT is its top speed?” This is the question which is perhaps most frequently asked about any new aeroplane, and it is certainly a question which is usually incorrectly answered. By this is not meant the natural tendency of manufacturers to be optimistic as to the paces of their latest progeny, but merely that the top speed of an aeroplane cannot be stated with accuracy until a number of careful and methodical measurements have been made. In this article a short account will be given of the errors inherent in the ordinary methods for indicating speeds, and descriptions of some of the methods evolved to measure speed—not only top speed but speed generally—to a high degree of accuracy.

This paper aims to investigate the influence of nonuniform gas speed across the build area on the melt pool depth during laser powder bed fusion. This study focuses on whether a nonuniform gas speed is a source of process variation within an individual build.

Parts with many single-track laser scans were printed and characterized in different locations across the build area coupled with corresponding gas speed profile measurements. Cross-sectional melt pool depth, width and area are compared against build location/gas speed profiles, scan direction and laser scan speed.

This study shows that the melt pool depth of single-track laser scans produced on parts are highly variable. Despite this, trends were found showing a reduction in melt pool depth for slow laser scan speeds on the build platform near the inlet nozzle and when the laser scans are parallel to the gas flow direction.

A unique data set of single-track laser scan cross-sectional melt pool measurements and gas speed measurements was generated to assess process variation associated with nonuniform gas speed. Additionally, a novel sample design was used to increase the number of single-track tests per part, which is widely applicable to studying process variation across the build area.

This paper aims to solve the typical thermal airflow sensor's high power consumption and integration difficulties, based on the FS5 thermal element and constant temperature measurement method, a flow sensor is developed with high measurement accuracy, low power consumption, small size, low cost and easy system integration.

A small wind tunnel was used to test and assess the sensor's measurement range, reaction time, stability, repeatability, measurement accuracy and multi-temperature calibration was performed in the temperature range of −10°C to 30°C. The effect of ambient temperature on the sensor's measurement data is investigated, and the coefficient correction method of power function was investigated to implement the sensor's software temperature compensation function.

The results show that the sensor is stable and repeatable, the output voltage has a power function relationship with the airflow rate, the flow rate measurement range is 0–18 m/s, the response time is less than 3 s, the measurement accuracy at high flow rates is within 0.4 m/s and the temperature-corrected airflow rate measurement error is less than 5%. Setting the temperature calibration interval to 2°C and 5°C has the same temperature compensation effect, reducing the sensor's calibration effort significantly.

This paper demonstrates that a thermostatic method is used to construct a thermal wind speed sensor that delivers accurate measurements in the wind speed measuring range of 0–18 m/s under test conditions. In addition, the sensor's performance is evaluated, and calibration tests for a wide range of temperatures are done. Finally, based on the power function correction method, a temperature compensation algorithm is proposed.

On‐board absolute speed sensors would be very useful in automotive applications in order to perform the measurement of the speed independently of the wheel rotation. Narrow beam Doppler sensors give a good accuracy but only operate if there is a reflecting obstacle in the antenna footprint on the road. Broad beam Doppler sensors have the advantage of offering a higher probability of getting a reflected wave, but they require multiple frequencies. A novel sensor is presented. It uses a single frequency emission, which leads to low cost devices. Simulations and measurements have been carried out which show that it is particularly well adapted to high‐risk situations, for instance icy or very wet road surfaces, when only a few reflecting obstacles are present. In such situations, the accuracy of the measurement is typically of the order of 0.5 per cent.

Relevant and reliable data from the surroundings in addition to the vibration measurements are required to achieve effective diagnosis and prognosis when a vibration‐based maintenance (VBM) policy is used. The main conclusion is that the variation in the machine load and speeds influences the amplitudes of rolling element bearing defect frequencies. Therefore, changes in the machine speed and load should be considered when interpreting vibration spectra. This will improve the effectiveness and accuracy of fault diagnosis and prediction of the time to maintenance action. The paper classifies stoppage times and highlights the reasons behind them. Also, it discusses the consequential economic losses incurred by unplanned stoppages. During the period covered by this study (58 days), the total stoppage time was about 76.6 days and caused appreciable economic losses of about 2.3 million SEK.

PROGRESS in most branches of engineering has been dependent upon model tests, and in no branch has the testing of models been of greater importance than in that of aeronautics. The earliest flights were made on models; and after the first successful flight of the full‐sized aeroplane, the development of aircraft to their present state of efficiency has been bound up, at every step, with the information obtained from model tests.

A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by equipping the rotor with a diffusing channel ended with a brim (diffuser augmented wind turbine – DAWT). The purpose of this paper is to design an experimental stand and perform the measurements of velocity vector fields through the diffuser and power characteristic of the wind turbine.

The experiments were carried out in a small subsonic wind tunnel at the Institute of Turbomachinery, Lodz University of Technology. An experimental stand design process as well as measurement results are presented. Model size sensitivity study was performed at the beginning. The experimental campaign consisted of velocity measurements by means of particle image velocimetry (PIV) and pneumatic pitot probe as well as torque and rotational velocity measurements.

Characteristics (power coefficient vs tip speed ratio) of the bare and shrouded wind turbine were obtained. The results show an increase in the wind turbine power up to 70-75 per cent by shrouding the rotor with a diffuser. The mechanisms responsible for such a power increase were well explained by the PIV and pneumatic measurement results revealing the nature of the flow through the diffuser.

Experimental stand for wind turbine rotor testing is of a preliminary character. Most optimal methodology for obtaining power characteristic should be determined now. Presented results can serve as good input for choice of stable and reliable control system of wind turbine operational parameters.

A 3 kW DAWT is being developed at the Institute of Turbomachinery, Lodz University of Technology. Aim of the study is to design a compact and smart wind turbine optimised for low wind speed conditions. Developed wind turbine has a potential to be used as an effective element within a net of distributed generation, e.g. for domestic use.

Research carried out is the continuation of theoretical study began in 1970s. It was also inspired by practical solutions proposed by Japanese researchers few years ago. Presented paper is the summary of work devoted to optimisation of the DAWT for wind conditions in the region. Original solution has been applied, e.g. for experimental stand design (3D printing application).