Here are some interesting texts on interesting topics. They mostly tackle the use of Teconer's products and their features. The articles contain author's opinions, questions and suggestions, are therefore a basis for discussion and are not intended to be the final word.

Meteorological Technology World Expo

Teconer participated in the Meteorological Technology World Expo 10.-12.10.2017 in Amsterdam. Thank you for visiting us and having interest in our products.

Welcome to visit us again in coming exhibitions.

Teconer booth in Amsterdam 2017.

Congress seminar presentation "Optimizing Usage of Anti-Icing Chemicals by Road Condition Monitoring" by Taisto Haavasoja in Brussels 2015.

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Installation of Road Condition Monitor RCM411 to Vehicles

RCM411 can be installed to almost any location in any type of vehicle. The distance to road surface can be varied from half a meter to much larger heigths. Nevertheless, we recommend to install at a low position for maximizing the optical signal and producing most stable results.

Locating the sensor in the rear of a vehicle is most challenging due to turbulences, exhaust gases, and splashes from wet road surfaces or potholes. The sensor window is protected by a long tube, which has proven very valuable in keeping the sensor window clean in the worst conditions. Should some dirt get on the window, it would be convenient to enable an easy clean up.

The optimal location would be in the front of the vehicle where there is less water spray and splashes. Installation in front can be challenging without modifying some parts of the vehicle. However, many vehicles have free space behind the front grill, which would be a good location for the sensor. In buses the front grill is often openable without tools and there is an adequate space to install an RCM411 sensor as shown in the photograph below.

RCM411 installed in front of a bus with the hinged grill opened.

Buses, taxes and maintenance vehicles provide a good platform for installation of road condition sensors. These type of vehicles can be used to collect automatically road condition data to observe continuously changes in wintry road conditions. Since weather conditions change typically during hours, it may be enough to install only a few bus sensors to follow a given route with a satisfactory temporal and spatial coverage.

The mobile data is far more accurate than fixed road weather station data due to the sparse density of stations and small size of measurement spot. The data can be complemented by photographs taken by the mobile devices, which collect the data from sensors. Servicing of the sensors at the depot will save both time and expenses. Fine-tuning of the calibration may be finalized through the web site, and the system firmware will be automatically updated, when appropriate.

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Economic Implications of Aggregate Moisture Measurements

Considerable savings and higher quality of concrete may be gained by use of moisture sensors in the concrete industry worldwide. Currently it seems that measuring the moisture in the aggregates is far from being a systematic procedure.

Concrete strength is determined mainly by water to cement ratio (w/c). A typical dependence of strength on w/c is shown in Figure 1. If the water in aggregate is not measured accurately, the inaccurate amount of water must be compensated by additional cement. The inaccuracy is on the order of 2 percent or even more in fine aggregates, which are typically used about 1 ton per 1 m³ of concrete. This additional 20 kg of water requires 40 kg more cement per 1 m³ at w/c = 0.5 in order not to fall below the chosen level of computational strength of the concrete. Approximately half of this can be saved with the help of a precise moisture measurement of the aggregates.

Figure 1. Typical dependence of concrete compressive strength on water to cement ratio.

Considering the cement price to be 100 EUR per ton, the loss is about 2 EUR/m³. For a small concrete plant which produces annually about 20 000 m³ this means a loss of 40 000 EUR per year. Typically 1-3 optical sensors are installed into one factory, and given these figures the payback time of taking into use the optical sensor solution will be less than 1 year.

The world consumption of concrete is in the order of 4,2 109 m³. Measuring moisture accurately in concrete production could save the cost of cement worth roughly 8 000 MEUR/year. This means also less CO2 emissions.

In addition to the direct monetary loss there are indirect costs caused by the poor quality of the concrete and its shorter durability. Instead of a potential lifetime of 100 – 200 years, it can drop to around 50 or less if the quality of concrete will not be maintained.

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Consistency of the RCM411 Measurements.

Consistency is a good measure of the usefulness of a sensor. In the same situation one should be able to repeat the measurement with same results. The client may see this as self-evident, but sensors that use complex indirect measurements may be surprisingly sensitive to small features in the measured substance. Optical sensors are typically sensitive to rapid variations in the ambient light level.
Teconer's intent is to thoroughly test the performance of its sensors. Results of these studies are published as openly as possible. This information enables the customer to better understand the possible abnormal behaviour of a sensor.
This text documents a test where a 12km (8 miles) loop was measured three times. All temperatures were near freezing (0 °C) and light snow begun just before the first drive. The easiest way to look at data may be using the map links where all details can be shown just by clicking point of interest along the route.

The state graph shows a typical near freezing situation. Part of the road is wet and another part is frozen. There was very little residual salt on the wet, slightly bigger, road.

The second and third round give very similar results, as expected, because the conditions were essentially stable. The North going, initially wet section, shows somewhat more ice, when it snows on the salted water.

Friction (distance)

The friction diagram shows that the friction is partly even significantly better than during the later rounds. The reduction in friction may very well result from the snow and very little residual salt. In general the friction profiles repeat very well.

Water amount (distance)

The water amount measurement is also very consistent. Current knowledge does not give a firm basis to specify the absolute accuracy of the results. The results are roughly correct and very applicable for road maintenance purposes. Other components (e.g. ice) make the estimation of the amount even more difficult.
Although there was no dry surface in this test, we know that RCM411 detects dry pavement very well in all circumstances. That is very important to know, because the dry surface seldom freezes, or at least does not rapidly become slippery. Many of our customers and partners are thus investigating the possibility to automatically control the salt spreader base on the measured water amount and maybe weather forecast. In a Swedish article the conclusion is that that kind of method would lead to significant reduction in salt use. Also the statistical (repeated measurements) amount of water on a certain road section might give a signal of expected problems in winter maintenance. As far as we know, this kind of "water mapping" has not taken place anywhere. The RCM411 would be an excellent sensor in gathering the data.

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