Measurement System

Knowledge learned from research has been effectively transferred to the agricultural industry in some areas and poorly transferred in others. Knowledge that has been used to create a thing such as pharmaceutical or a piece of equipment is more likely to be adopted by industry than a behavioral management technique that reduces stress to improve productivity and welfare. The author has observed during her career that some people will purchase a new cattle handling system which is designed with animal behavioral principles but they will continue to handle cattle roughly. People are more likely to purchase new equipment than use easy to learn low stress techniques for moving cattle. Even when financial benefits are clear, some people find it difficult to believe that a purely behavioral management method will really work. Many studies done during the last twenty years on dairies and pig farms have clearly shown the benefits of good stockmanship on animal productivity. Unfortunately a large segment of the livestock industry has been slow to implement improved stockmanship. I would like to speculate that a possible reason why some people resist learning better stockmanship is because a good stockperson must recognize that an animal is a conscious being that has feelings.

By using a recently developed, wavelength-sensitive BDJ (buried double p-n junction) detector, a reliable and inexpensive method for colorimetric determination of seawater pH is suggested. A BDJ detector is a silicon photodetector providing two photocurrents proportional to the incident radiation, and the ratio of photocurrents is wavelength-dependent. In the visible range, the ratio of the deep junction photocurrent to the shallow junction one is monotonic increasing with the wavelength. This characteristic allows the BDJ detector to be applied to the detection of colours or spectral changes. For colorimetric seawater pH measurement with the use of tymol blue (TB) as pH-indicator dye, we propose a simple and reliable method based on the concept of the photocurrent ratio. By determining the concentration of the acidic form and that of the alkaline form in a dye solution, the pH can be deduced. The presented method has experimentally been veri®ed, with a more stable dye, bromo phenol blue (BPB), which has very similar absorption spectra to those of the TB dye. As the design and fabrication of the BDJ detector requires only a standard CMOS process, a miniaturised pH-measuring system can be developed, thanks to the potential of on-chip integration of BDJ detector and electronic circuitry.

We present our work on the implementation and calibration of a multi sensor measuring system. The work is part of a large scale research project on optical measurement using sensor actuator coupling and active exploration. This project is a collaboration of researchers from seven institutes of the University of Stuttgart including photogrammetry, mechanical engineering and computer science. The system consists of optical sensors which can be manipulated in position and orientation by robot actuators, and light sources which control illumination. The system performs different tasks including object recognition, localization and gauging. Flexibility is achieved by replacing the common serial measurement chain by nested control loops involving autonomous agents which perform basic tasks in a modular fashion. The system is able to inspect and gauge several parts from a set of parts stored in a 3-D model database. The paper gives an overview of the entire system and details some of the photogrammetry-related aspects such as the calibration of the different sensors (cameras, stereo-head, stripe projector), the calibration of the measurement robot using photogrammetric measurements, as well as data processing steps like segmentation, object pose determination, and gauging.

An in-line sampling and dilution system for droplet aerosols from medical nebulisers is described. The device has been designed to interface with a white light aerosol spectrometer (welas ᭨ 2070, Palas ᭨ GmbH, Germany) that allows measurements of highly concentrated aerosols. The performance of the sampling system in terms of the measured particle size distribution (PSD) is compared to EN 13544-1 approved measurement techniques as well as to techniques proposed for the European Pharmacopoeia (2.9.44). The measured PSD compares favourably to the ones measured by a Next Generation Impactor, cooled prior to measurement, and by laser diffraction analysed by the Mie theory. This study included three nebulisers (Pari LC Plus, Aeroneb Pro, Omron MicroAIR). The measuring system presented in this study offers a time saving alternative for the measurement of PSD as well as quantity of aerosols from medical nebulisers that is of interest for quality control in the pharmaceutical industry.

Background/aim: The technique of photoretinoscopy is unique in being able to measure the dynamics of the oculomotor system (ocular accommodation, vergence, and pupil size) remotely (working distance typically 1 metre) and objectively in both eyes simultaneously. The aim of this study was to evaluate clinically the measurement of refractive error by a recent commercial photoretinoscopic device, the PowerRefractor (PlusOptiX, Germany). Method: The validity and repeatability of the PowerRefractor was compared to: subjective (noncycloplegic) refraction on 100 adult subjects (mean age 23.8 (SD 5.7) years) and objective autorefraction (Shin-Nippon SRW-5000, Japan) on 150 subjects (20.1 (4.2) years). Repeatability was assessed by examining the differences between autorefractor readings taken from each eye and by re-measuring the objective prescription of 100 eyes at a subsequent session. Results: On average the PowerRefractor prescription was not significantly different from the subjective refraction, although quite variable (difference +0.05 (0.63) D, p = 0.41) and more negative than the SRW-5000 prescription (by 20.20 (0.72) D, p,0.001). There was no significant bias in the accuracy of the instrument with regard to the type or magnitude of refractive error. The PowerRefractor was found to be repeatable over the prescription range of 28.75D to +4.00D (mean spherical equivalent) examined. Conclusion: The PowerRefractor is a useful objective screening instrument and because of its remote and rapid measurement of both eyes simultaneously is able to assess the oculomotor response in a variety of unrestricted viewing conditions and patient types.

The AC response measurement system is presented. System structure, operation and main units operation are described. The connection setup for a few most common tasks is presented. The obtained results are given. It has been indicated that AC response can be investigated for ultrasonic preamplifier, matching transformer, system filters and ultrasonic transducers. The system is controlled by a personal computer via USB interface.

This paper describes the development of a low cost coaxial moisture sensor for the determination of moisture content (30% to 80% wet-weight basis) of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 1 GHz and 5 GHz was ...

Laser measurement applications Tunable laser measurement Thin film Laser tuning Thin film measurement applications Fourier-transform based analysis a b s t r a c t Film thickness is not only a crucial parameter in producing processes, such as semiconductor and optics production, but also a monitored variable in chemistry and biology, for example for tissue microscopy. Many working principles have been demonstrated and are in use in different fields due to their different limitations (observation film thickness, accuracy, measurement speed, etc.). One of these working principles is thin film reflectometry (TFR). One method is based on a laser source and monitors the reflected intensity over growing film time. Another one employs a spectrally broad light source and measures the reflected intensity using a spectrometer. We introduce and demonstrate a measurement system based on a tunable laser stage. There are several different setups for laser wavelength tuning. One of the most promising solutions is based on monolithic laser diodes. Rapid tuning of the lasers wavelength is crucial for achieving high measurement rates. Monolithic laser diodes offer highest tuning rates and hence high performance. On the other hand, mechanically tunable lasers show broadband spectra that result in higher thickness accuracy in this particular application. Hence, we show a comparison of thin film measurements with a monolithic and a mechanically tunable laser source. This comparison shows that the measurement accuracy of the monolithic laser diode can compete with mechanical tuning. Furthermore, it is a promising approach when measurement tuning speed is an issue.

The SMAF (Functional Autonomy Measurement System) is a 29-item scale developed according to the WHO classification of disabilities.It measures functional ability in 5 areas: activities of daily living (ADL) [7 items], mobility [6 items], communication [3 items], mental functions [5 items] and instrumental activities of daily living (IADL) [8 items]. For each item,the disability is scored on a 5-point scale:0 (independent), -0.5 (with difficulty), -1 (needs supervision), -2 (needs help), -3 (dependent). Resources available to compensate the disability are also evaluated, and a handicap score is deducted. Stability of the resources is also assessed. A disability score (on -87) can be calculated, together with sub-scores for each dimension. SMAF must be administered by a health professional (nurse or social worker) who scores the subject after obtaining the information, either by questioning the subject and proxies, or by observing and even testing the subject.This instrument was submi...

The low-temperature isobaric heat capacities (C p ) of b-and c-Mg 2 SiO 4 were measured at the range of 1.8-304.7 K with a thermal relaxation method using the Physical Property Measurement System. The obtained standard entropies (S°2 98 ) of b-and c-Mg 2 SiO 4 are 86.4 ± 0.4 and 82.7 ± 0.5 J/mol K, respectively. Enthalpies of transitions among a-, b-and c-Mg 2 SiO 4 were measured by high-temperature dropsolution calorimetry with gas-bubbling technique. The enthalpies of the a-b and b-c transitions at 298 K (DH°2 98 ) in Mg 2 SiO 4 are 27.2 ± 3.6 and 12.9 ± 3.3 kJ/ mol, respectively. Calculated a-b and b-c transition boundaries were generally consistent with those determined by high-pressure experiments within the errors. Combining the measured DH°2 98 and DS°2 98 with selected data of in situ X-ray diffraction experiments at high pressure, the DH°2 98 and DS°2 98 of the a-b and b-c transitions were optimized. Calculation using the optimized data tightly constrained the a-b and b-c transition boundaries in the P, T space. The slope of a-b transition boundary is 3.1 MPa/K at 13.4 GPa and 1,400 K, and that of b-c boundary 5.2 MPa/K at 18.7 GPa and 1,600 K. The post-spinel transition boundary of c-Mg 2 SiO 4 to MgSiO 3 perovskite plus MgO was also calculated, using the optimized data on c-Mg 2 SiO 4 and available enthalpy and entropy data on MgSiO 3 perovskite and MgO. The calculated post-spinel boundary with a Clapeyron slope of -2.6 ± 0.2 MPa/K is located at pressure consistent with the 660 km discontinuity, considering the error of the thermodynamic data.

The paper describes a new measurement system for the evaluation of the objective performances of a car audio apparatus. The system makes use of a 4-channels sound board fitted in a low-cost PC, which drives separately the 4 loudspeaker sections of the car. The excitation signal is a periodic maximum length sequence. The response of the system is sampled simultaneously with 2 binaural dummy heads. The complete test takes less than 1 minute, thanks to a software specifically developed for this task.

We report an ultracompact label-free biosensor that uses a vertical-cavity surface-emitting laser (VCSEL)-based measurement system for the characterization of biomolecular interactions. It consists of a VCSEL, a plastic guided-mode resonant filter, and two p-in detectors. The system has demonstrated very high sensitivity to molecules on top of the sensor.

This paper describes part of a comprehensive National Air Emissions Monitoring Study (NAEMS) conducted at a swine finishing farm located in the state of Indiana, in the United States. The NAEMS was a 2-year study of emissions from animal feeding operations that produce pork, chicken meat, eggs, and milk. It provided emission data for the U.S. Environmental Protection Agency (EPA) to develop tools for estimating emissions from livestock farms. The study in Indiana focused on quantifying and characterizing emissions of gases, particulate matter (PM), and volatile organic compounds (VOCs) from a swine finishing quad (four 1000head rooms under one roof). Long-term continuous and quasi-continuous measurements were conducted with 157 on-line measurement variables using an array of instruments and sensors for gas and PM concentrations, fan operation, room static pressures, indoor temperature and humidity, animal activity and feeding times, and weather conditions. Pig inventory and weight, feed type and quantity, and manure accumulation and composition were also documented. Systematic tests of the measurement system were conducted. Monitoring methodologies, instrumentation applications, equipment maintenance, quality controls, and system performances are presented and can be used as a reference in assessing research quality and improving future environmental studies on livestock facilities. Implications: Aerial pollutant emissions became a major environmental issue for livestock operations after farms increased significantly in size. Gas and particulate matter emissions from livestock production may cause various environmental impacts such as odor and noxious gas exposure in neighboring areas. In this study, comprehensive and long-term emissions of gases and PM at a Midwestern U.S. commercial swine finishing farm were continuously monitored for 2 years. The methodologies, quality assurance procedures, and results of this study can be used to plan future emission monitoring projects, improve baseline emission databases, and validate emission models.

On two days during SUCCESS, the NASA DC-8 flew carefully designed flight tracks to sample wave clouds downstream of the Rocky mountains. Wave morphology was deduced by applying linear perturbation theory to in-situ measurements of the Meteorological Measurement System (MMS) and remotely sensed isentrope profiles of the Micro-wave Temperature Profiler (MTP). Vertical winds from the MMS were consistent with updraft velocities derived from air parcel displacements estimated from the MTP. Derived wave characteristics and cooling rates are useful inputs to cloud microphysics models.

We studied the familiarisation time required for reliable sagittal-plane knee kinematics and temporal-distance gait measurements to be obtained from treadmill walking. We also studied whether knee kinematics and temporal-distance gait measurements obtained from familiarised treadmill walking can be generalised to overground walking. Sixteen subjects without pathology walked on a level overground walkway and on a treadmill. A motion measurement system was used to measure sagittal plane knee movements and temporal-distance gait parameters during overground and treadmill walking. Highly reliable knee kinematics and temporal-distance gait measurements [intraclass correlation coefficient (ICC)(2,1) ] 0.93] were found after 6 min of treadmill walking. These measurements, obtained after 6 min of treadmill walking, were highly correlated with and not significantly different to those of overground walking. Reliable measurements that can be generalised to overground walking, can be obtained from the treadmill within a familiarisation time of 6 min.

In order to perform on-line measuring and detection of PD signals, a total solution composing of an HFCT, A/D converter and a complete software package is proposed. The software package includes compensation of HFCT contribution, filtering and noise reduction using wavelet transform and soft calibration routines. The results have shown good performance and high accuracy.

A framework for measuring the performance of distributed programs is presented. This framework includes a model of distributed programs, a description of the measurement principles and methods, and a guideline for implementing these ideas. The author describes a measurement system called the Distributed Programs Monitor (DPM), which he has constructed on the basis of these concepts. DPM has been implemented and used for measurement studies on two different operating systems, DEMOS/MP and Berkeley Unix.

This paper introduces a new thin film non-symmetric array of microelectrodes for impedance diagnostics and characterization of hydroscopic properties of human skin. Using a suitable design of the planar thin film electrode system we change an orientation of vector intensity of the electric field lines from transversal to longitudinal direction relative to the skin surface. Electrical properties of measured system and electrostatic field of interdigitated array (IDA) electrodes were simulated. With regard to theoretical and simulated analyses, the non-symmetric interdigitated arrays of electrodes were designed and fabricated. Nonsymmetric IDA electrodes were tested in KCl solutions and applied for impedance monitoring of human skin. ᮊ

In this paper a new four electrode sensor for water conductivity measurements is presented. In addition to the sensor itself, all signal conditioning is implemented together with signal processing of the sensor outputs to determine the water conductivity. The sensor is designed for conductivity measurements in the range from 50 mS/m up to 5 S/m through the correct placement of the four electrodes inside the tube where the water flows.

Strict regulatory requirements for SAR compliance testing around the world has increased the need for accurate and precise testing methodologies. Such requirements are also required conform to quality management accreditation guidelines such as ISOOEC 17025. Equipment calibration, environmental conditions, tissue simulating solution characteristics, measurement setup all contribute to the accuracy of a S A R measurement. System verification is one way to help assure accurate and precise measurements by verifying the measurement repeatability of a reference on a daily basis. A tuned % wave dipole is recommended by the standards for this standards. This study proposes a printed dipole as a reference for daily system verification that meets all requirements of IEEE 1528, FCC Supplement C, and CENELEC EN 50361. The printed design adds the benefits of being more cost effective, robust, and easier to position for testing.

1] Landfills are one of the largest sources of methane to the atmosphere, yet their emissions are seldom measured. This results in high uncertainties in national emission estimates. We developed a Flame Ionization Detector-based micrometeorological measurement system and tested it at a large municipal landfill in Finland. The technical characteristics of the system allowed use of the eddy covariance method, enabling emission monitoring at a much lower cost than employing a Tunable Diode Laser instrument, which we used as a reference. Combining methane and carbon dioxide flux measurements we were able to estimate the methane generation rate, gas collection efficiency and oxidation rate in the landfill surface layer. We showed that the oxidation fraction may differ significantly from the default value used in the IPCC emission modelling, and that high emission rates were observed in the active deposition areas of the landfill. Citation: Laurila, T., J.-P. Tuovinen, A. Lohila, J. Hatakka, M. Aurela, T. Thum, M. Pihlatie, J. Rinne, and T. Vesala (2005), Measuring methane emissions from a landfill using a cost-effective micrometeorological method, Geophys.

Single-crystals of MnFe2O4 nanorods with an average diameter of 20 nm and length of 250 nm were synthesized by a hydrothermal process at 180 °C after 12 h. High-resolution transmission electron microscopy (HRTEM) and electron diffraction (ED) analysis revealed that the nanorods grow along the [110] axis, which is one of the easy magnetization axes of the material MnFe2O4. It was found that the nanorods exhibited a saturation magnetization (Ms) of 68.02 emu/g, which is much higher than that of quasi-spherical particles of MnFe2O4, prepared by other approaches such as solid-state reaction methods (Ms = 36.7 emu/g), and coprecipitation processes followed by annealing in vacuo at 400 °C (Ms = 24.4 emu/g). The oriented growth along the easy magnetization axis of MnFe2O4 was suggested to be responsible for the improvement of magnetic properties of MnFe2O4 nanorods. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Continuous measurements of the surface water CO 2 partial pressure (pCO 2) and the chlorophyll a fluorescence were performed in the Baltic Sea using a fully automated measurement system deployed on a cargo ship. The ship commuted regularly at two day intervals between the Mecklenburg Bight (Luebeck) and the Gulf of Finland (Helsinki). The pCO 2 data collected during June 2003 and September 2004 were used to identify biological production events such as the spring bloom and the midsummer cyanobacteria bloom in five different sub-regions. To quantify the net biomass production, the decrease of the total CO 2 , N C T (normalized to a uniform alkalinity), during the production periods was calculated using the pCO 2 , temperature and salinity records and the mean alkalinity. Taking into account the CO 2 air/sea exchange and the formation of dissolved organic carbon, a simple mass balance yielded the net production of particulate organic carbon which represents the total biomass. The chlorophyll a concentrations obtained from the fluorescence data showed peaks that in most cases coincided with the production maxima and thus supported the interpretation of the pCO 2 data. The production during both the spring bloom (2004) and the midsummer nitrogen fixation period (2003) increased by a factor of about three from the southwest to the northeast. For the spring bloom our estimates were significantly higher than those based on the winter nutrient supply and Redfield C / N and C / P ratios. This indicated the existence of additional nutrient sources such as dissolved organic nitrogen, early nitrogen fixation and preferential P mineralization. Midsummer N C T minima were observed only in 2003 and used to quantify the nitrogen fixation activity and to characterize its interannual variability.

A mountain wave event, observed at the southern tip of Greenland on January 6, 1992, was corroborated by three experiments: the Meteorological Measurement System (MMS), the Microwave Temperature Profiler (MTP), and the Reactive Nitrogen Instrument (NO/NOv). Gravity wave signatures with classical phase relationsh•p between wind and temperature were observed on both the outbound and inbound legs at different altitudes. The waves showed both vertically propagating and evanescent properties. Characteristics of the dominant wave mode are: wavelength --35 km; vertical displacement • 0.8 km, and peak-to-peak vertical wind .• 6 ms -1. With the prevailing wind at = 37 ms -1, the stratospheric temperature was reduced by 6K to 195.5K within 8 minutes. The implication and potential impact of mountain lee waves on the formation of polar stratospheric clouds (PSC's) are discussed.

A non-intrusive optical probe has been developed for the identification of flow patterns during liquid–liquid two-phase flow through a conduit. It is based on the difference in optical properties of the respective phases and works on the basis of the proportion of light attenuated and scattered by the two-phase mixture. The measuring system consists of a laser source, a light-dependent

The superficial appearance and color of food are the first parameters of quality evaluated by consumers, and are thus critical factors for acceptance of the food item by the consumer. Although there are different color spaces, the most used of these in the measuring of color in food is the L*a*b* color space due to the uniform distribution of colors, and because it is very close to human perception of color. In order to carry out a digital image analysis in food, it is necessary to know the color measure of each pixel on the surface of the food item. However, there are at present no commercial L*a*b* color measures in pixels available because the existing commercial colorimeters generally measure small, non-representative areas of a few square centimeters. Given that RGB digital cameras obtain information in pixels, this article presents a computational solution that allows the obtaining of digital images in L*a*b* color units for each pixel of the digital RGB image. This investigat...

The perceptual analysis measurement system (PAMS) is an objective model designed to evaluate the perceived speech quality of telephone networks. Two key network properties, linear filtering and variable bulk delay, made previous models unsuitable for end-to-end measurement. This paper outlines the innovations that allow PAMS to take these properties into account. Variable delay occurs in packet-based transmission such as voice over IP. It is addressed by a time alignment algorithm that identifies delay changes in silent periods and during speech. Linear filtering, typically caused by analogue interfaces, is dealt with using a transfer function estimation and equalisation technique designed for robustness to non-linear distortions. A further development is the use of a constrained non-linear regression method to map error parameters to predicted subjective quality.

Growing industrialization and its implication to nuisance smells led to an increased interest in odour monitoring. As a result of that a variety of sensors and methods to detect or analyse odour were developed over the last few years. The function of the chemosensor system combined with a pre-concentrated unit is explained. The concept and implementation of an odour measuring method using a chemosensor system in combination with olfactometry is described. The odour measurement system was installed at the outlet of a charcoal filter at a waste incineration plant. For a period of three months the system operated unsupervised, taking odour samples continuously, calculating the odour concentration online and signaling odour events to a control centre. The method of odour measurement has proven successful and has shown the feasibility of detecting a filter breakthrough using a chemosensor system.

In this paper we report a simple tuning methodology of high temperature superconducting (HTS) microstrip filters. In order to establish this new tuning approach a 5 pole lumped element HTS bandpass filter, centre frequency 800 MHz, narrowband (bandwidth, 7.6 MHz), is designed and fabricated on a 2 inch (diameter) YBa 2 Cu 3 O 6.94 thin film of thickness 700 nm and lanthanum aluminate (LaAlO 3 ) substrate of 0.5 mm thickness. The filter was etched using conventional photolithography and a wet chemical etching process. The 5 pole lumped element filter is tested in an integrated RF-cryocooler measurement system at 65 K and also in liquid nitrogen (77 K). We demonstrate a 19.3 MHz downward shift of the centre frequency of the 5 pole filter response. This is achieved by overlaying two layers of thin dielectric tape (PTFE) (50.0 µm thickness, permittivity 3.2) over the conducting patterned part of the filter surface. A full wave electromagnetic analysis of the dielectric environment of this tuning arrangement matches the measured response closely. To improve the passband response, the filter is tuned in liquid nitrogen, placing pieces of sapphire rods over the resonators of the filter layout.

In stochastic inventory systems unfolding uncertainties in demand lead to the revision of earlier replenishment plans which in turn results in an instability or so-called system nervousness. In this paper, we provide the grounds for measuring system nervousness in non-stationary demand environments, and gauge the stability and the cost performances of (R,S) and (s,S) inventory policies. Our results reveal that, both the stability and the cost performance of inventory policies are affected by the demand pattern as well as the cost parameters, and the (R,S) policy has the potential to replace the cost-optimal (s,S) policy for systems with limited flexibility.

Many different methods have been developed for the measurement of angular speed. Each successive method has attempted to improve measurement performance using a different strategy to process encoder signals based on two basic principles: counting the number of pulses in a given time duration and measuring the elapsed time for a single cycle of encoder signal. A review of existing methods reveals that little effort has been made in the measurement of instantaneous, multi-channel, wide-range angular speed. As a result, this paper aims to develop a method that provides instantaneous speed information in the form of angular displacement. It addresses the general process and considerations that ensure effective measurement of instantaneous angular speed (IAS). The paper then presents two different techniques: one is based on a general-purpose data acquisition system, another uses pure software implementation. Both methods aim to maximise the use of hardware resources without incurring additional costs in the form of upgrades to the measurement system. Finally, an optimisation of measurement system parameters for a reliable IAS measurement has been carried out based on measurement error analysis. r

d e n t a l m a t e r i a l s 2 6 ( 2 0 1 0 ) 947-953 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . i n t l . e l s e v i e r h e a l t h . c o m / j o u r n a l s / d e m a a b s t r a c t Objectives. The contraction stress of a silorane-based material and a new low-shrinkage nanohybrid composite were compared to three conventional dimethacrylate-based resin composites using two different measuring systems. It was hypothesized that the silorane-based material and the low-shrinkage nanohybrid composite would exhibit lower contraction stress than dimethacrylate-based composites irrespective of measuring system. Methods. The materials tested were Filtek Silorane LS (3M ESPE), Venus Diamond (Heraeus Kulzer), Tetric EvoCeram (Ivoclar Vivadent), Quixfil (Dentsply DeTrey), and Filtek Z250 (3M ESPE). Shrinkage stress was assessed using a stress-strain analyzer consisting of two opposing attachments, one connected to a load sensor and the other fixed to the device, or a system fixed to a universal testing machine with an extensometer as a feedback system. All specimens were light-cured with 20 J/cm 2 ; the contraction force (N) generated during polymerization was continuously recorded for 300 s. Contraction stress (MPa) was calculated at both 40 s and 300 s. Data were statistically analyzed by three-way ANOVA and Tukey's post hoc test (˛= 0.05). Results. Venus Diamond exhibited the lowest stress under both experimental conditions. Stress values scored as follows: Venus Diamond < Tetric EvoCeram < Filtek Silorane LS < Quixfil < Filtek Z250 (p < 0.05). Stress values measured with the stress-strain analyzer were significantly lower than those measured with the universal testing machine with feedback.

A rainfall interception measuring system was developed and tested for open-grown trees. The system includes direct measurements of gross precipitation, throughfall and stem¯ow, as well as continuous collection of micrometeorological data. The data were sampled every second and collected at 30-s time steps using pressure transducers monitoring water depth in collection containers coupled to Campbell CR10 dataloggers. The system was tested on a 9-year-old broadleaf deciduous tree ( pear, Pyrus calleryana`Bradford') and an 8-yearold broadleaf evergreen tree (cork oak, Quercus suber) representing trees having divergent canopy distributions of foliage and stems. Partitioning of gross precipitation into throughfall, stem¯ow and canopy interception is presented for these two mature open-grown trees during the 1996±1998 rainy seasons. Interception losses accounted for about 15% of gross precipitation for the pear tree and 27% for the oak tree. The fraction of gross precipitation reaching the ground included 8% by stem¯ow and 77% by throughfall for the pear tree, as compared with 15% and 58%, respectively, for the oak tree. The analysis of temporal patterns in interception indicates that it was greatest at the beginning of each rainfall event. Rainfall frequency is more signi®cant than rainfall rate and duration in determining interception losses. Both stem¯ow and throughfall varied with rainfall intensity and wind speed. Increasing precipitation rates and wind speed increased stem¯ow but reduced throughfall. Analysis of rainfall interception processes at dierent time-scales indicates that canopy interception varied from 100% at the beginning of the rain event to about 3% at the maximum rain intensity for the oak tree. These values re¯ected the canopy surface water storage changes during the rain event. The winter domain precipitation at our study site in the Central Valley of California limited our opportunities to collect interception data during non-winter seasons. This precipitation pattern makes the results more speci®c to the Mediterranean climate region.

The main goal of this paper is to experimental examine some of the properties of two different wireless communication modules, ZigBee and SimpliciTI, which are employing two different transmission standards. This paper is a part of wider research aimed to examine and evaluate the different wireless transmission standards to use in distributed measurement systems.

Impedance plethysmography (IPG) is a safe and noninvasive method for measuring peripheral hemodynamics. This paper’s aim is to develop a medical device system for a continuous monitoring of this parameter using the impedance technique. This system combines the advanced analog amplifier with the calculation power of digital signal processing to acquire real time monitoring. Our bioimpedance measuring system uses a generator which is under microprocessor control. Experimental investigations are conducted in order to determine the optimum interrelation between current injector output characteristics, power supply and electrode spacing.

Undoubtedly voltage and current measurements under distorted conditions have recently gained more and more importance in the actual electric market; the deregulation acting in this field with the consequential liberalization and the augmented request of monitoring capabilities on the power quality from the power suppliers, is at the origin of an increased demand of measurement instruments of the various electric

Various methods are used to locate cloud-to-ground lightning flash. The accuracy of the methods depends on the number of sensor stations, station topology, mathematical model adopted for the analyses, and type of measuring equipment. For a single station with the configuration of short baseline in a measuring system, the accuracy analysis is mostly based on the chosen mathematical equations (and all relative assumptions) which can be solved in either linear or nonlinear mode. This paper concentrates on the simulation of a lightning flash based on Time of Arrival (TOA) method by utilizing three broadband antennas. The accuracy of the TOA method is also evaluated in this work. A Matlab based simulation of the measuring system is implemented to construct a randomly located lightning flash with its corresponding electromagnetic radiation. Then, suitable mathematical models used as measurement systems based on the TOA method to determine the azimuth and elevation angles.

Abstruct-Optimal measurement and control procedures with adaptive algorithms based on dynamically evaluated output signals for operating a dew point hygrometer are discussed. The influence of dew condensation and evaporation time constants and the amplitude of mirror overheating and overcooling, as well as limits of the flow rate of the measured gas and the thickness of the dew layer upon dew point detection and the accuracy of the dynamically measured mirror temperature, are described. Flow diagrams for computer procedures and schematic diagrams of electronic measurement systems are included.