Ruiskubetonin kehittäminen polymeerinotkistimien avulla

Insinöörityö tehtiin projektina Finnsementille ja Ruskon Betonille. Finnsementti on Suomen suurin sementin toimittaja ja Ruskon Betoni Suomen toiseksi suurin valmisbetonin toimittaja. Yritykset tekevät paljon kehitystyötä Ruskon Betonin ollessa merkittävä asiakas Finnsementille sementin ja lisäaineiden tilaajana. Työn aiheena oli testata kahdeksaa uutta polymeerinotkistinta Contestan laboratoriotiloissa ja valita tehdastestien perusteella kolme parasta notkistinta kenttätesteihin Ruskon Betonin betoniasemalla tuotannon kautta käytettävään valmisbetoniin. Tavoitteena oli löytää potentiaalinen uusi notkistin korvaamaan vanha käytössä oleva notkistin, jota käytetään ruiskubetonin tekemisessä. Työhön kuului myös vierailu Helsinkiin rakennettavan Länsi-Metron työmaalla sekä ruiskubetonointi operaattorien haastattelu eri massojen käyttöominaisuuksista. Ruiskubetonin kehityksen kannalta työssä haettiin hyvää työstettävyyttä betonimassalle ja aiempaa pidempää työstettävyysaikaa. Myös vesisementtisuhteita haluttiin saada pienemmäksi. Edellä mainittuja asioita testattiin normaaleilla betonin laboratoriokokeilla. Työssä saavutettiin sille asetetut tavoitteet. Testauksen avulla löytyi yksi notkistin, joka oli muita parempi ja hyvä vaihtoehto uudeksi notkistimeksi. Tämä notkistin viedään CE -kokeisiin, josta tulee tulevaisuudessa oma tuote

Estimation of breast height diameter and trunk curvature with linear and single-photon LiDARs

International audienceContext: Precision forestry together with new sensor technologies implies Digital Forest Inventories for estimation of volume and quality of trees in a stand.Aims: This study compared commercial LiDAR, new prototype SPAD LiDAR, and manual methods for measuring tree quality attributes, i.e., diameter at breast height (DBH) and trunk curvature in the forest stand.Methods: We measured 7 Scots pine trees (Pinus sylvestris) with commercial LiDAR (Zeb Horizon by GeoSLAM), prototype SPAD LiDAR, and manual devices. We compared manual measurements to the DBH and curvature values estimated based on LiDAR data. We also scanned a densely branched Picea abies to compare penetrability of the LiDARs and detectability of the obstructed trunk.Results: The DBH values deviated 1–3 cm correlating to the specified accuracies of the employed devices, showing close to acceptable results. The curvature values deviated 1–6 cm implying distorted range measurements from the top part of the trunks and inaccurate manual measurement method, leaving space for improvement. The most important finding was that the SPAD LiDAR outperformed conventional LiDAR in detecting tree stem of the densely branched spruce.Conclusion: These results represent preliminary but clear evidence that LiDAR technologies are already close to acceptable level in DBH measurements, but not yet satisfactory for curvature measurements. In addition, terrestrial SPAD LiDAR has a great potential to outperform conventional LiDARs in forest measurements of densely branched trees

A high frame rate, 340 GHz 3D imaging radar for security

Funding: European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312745.The need for improved security at airports with high detection performance, high throughput rates and an improved passenger experience is motivating research into new sensing technologies. The European Union funded CONSORTIS project is addressing these aims by demonstrating a system which combines a submillimeter wave radar, a dual-band passive submillimeter wave camera and automatic anomaly detection software for reliable detection while ensuring passenger privacy. In this paper we describe the 340 GHz 16-channel FMCW radar which produces 3D maps of the subject with ∼1 cm3 voxel resolution over a 1 m3 sense volume at multi-hertz frame rates. The radar combines advanced transceiver electronics with high speed mechanical beam steering and parallelized processing to achieve this level of performance.Postprin

FT-IR-cPAS—New Photoacoustic Measurement Technique for Analysis of Hot Gases: A Case Study on VOCs

This article describes a new photoacoustic FT-IR system capable of operating at elevated temperatures. The key hardware component is an optical-readout cantilever microphone that can work up to 200 °C. All parts in contact with the sample gas were put into a heated oven, incl. the photoacoustic cell. The sensitivity of the built photoacoustic system was tested by measuring 18 different VOCs. At 100 ppm gas concentration, the univariate signal to noise ratios (1σ, measurement time 25.5 min, at highest peak, optical resolution 8 cm−1) of the spectra varied from minimally 19 for o-xylene up to 329 for butyl acetate. The sensitivity can be improved by multivariate analyses over broad wavelength ranges, which effectively co-adds the univariate sensitivities achievable at individual wavelengths. The multivariate limit of detection (3σ, 8.5 min, full useful wavelength range), i.e., the best possible inverse analytical sensitivity achievable at optimum calibration, was calculated using the SBC method and varied from 2.60 ppm for dichloromethane to 0.33 ppm for butyl acetate. Depending on the shape of the spectra, which often only contain a few sharp peaks, the multivariate analysis improved the analytical sensitivity by 2.2 to 9.2 times compared to the univariate case. Selectivity and multi component ability were tested by a SBC calibration including 5 VOCs and water. The average cross selectivities turned out to be less than 2% and the resulting inverse analytical sensitivities of the 5 interfering VOCs was increased by maximum factor of 2.2 compared to the single component sensitivities. Water subtraction using SBC gave the true analyte concentration with a variation coefficient of 3%, although the sample spectra (methyl ethyl ketone, 200 ppm) contained water from 1,400 to 100k ppm and for subtraction only one water spectra (10k ppm) was used. The developed device shows significant improvement to the current state-of-the-art measurement methods used in industrial VOC measurements

High resolution, wide field of view, real time 340GHz 3D imaging radar for security screening

Funding: Part of the research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 312745.The EU FP7 project CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) is developing a demonstrator system for next generation airport security screening which will combine passive and active submillimeter wave imaging sensors. We report on the development of the 340 GHz 3D imaging radar which achieves high volumetric resolution over a wide field of view with high dynamic range and a high frame rate. A sparse array of 16 radar transceivers is coupled with high speed mechanical beam scanning to achieve a field of view of ~ 1 x 1 x 1 m3 and a 10 Hz frame rate.Publisher PD

The CONSORTIS 16-channel 340-GHz security imaging radar

We have completed a 16-channel 340 GHz 3D imaging radar for next-generation airport security screening under the European Union funded CONSORTIS (Concealed Object Stand-Off Real-Time Imaging for Security) project. The radar maps a 1 x 1 x 1 m3 sense volume with ∼1 cm3 voxel resolution at multi-hertz frame rates. The radar has been installed in the CONSORTIS system enclosure and integrated with a passenger control system and command module. The full system will ultimately also incorporate a dual-band passive submillimeter wave imager and automatic anomaly detection software for reliable, ethical detection of concealed objects. A large data collection trial on targets of interest has been conducted to support the development of automatic anomaly detection software. Initial threat detection analysis indicates promising results against aviation-relevant objects including simulant dielectric threat materials.Publisher PD