Rate Meter Research Articles

Injection Rate Measurement of a Gaseous Fuel Injector Using a Beam Cut Method

Injection rate of a gaseous fuel injector was calculated by measuring the needle valve lift history. In our lab, a gaseous fuel injection rate meter using 1-dimensional pipe flow was developed. In the present study, the measurement accuracy of the injection rate meter was examined by comparing the theoretical injection rate estimated from the needle valve lift history. The needle valve lift was measured using an optical method. A small beam cut plate is attached to the needle valve of the gaseous fuel injector. A laser beam passes through the beam cut plate, and the variation of the beam intensity was measured with a photo sensor. From the beam intensity, the needle valve lift history was estimated. One-dimensional, compressible, inviscid, adiabatic flow was assumed, and the instantaneous mass flow rate through the needle valve sheet, the injector sack, and the injection hole was estimated. The estimated injection rate was compared with that obtained with the gaseous fuel injection rate meter. The estimated and measured injection rates agree relatively well even at transient duration. It is shown that the injection rate meter has high reliability and accuracy.

Improvement of Injection Rate Measurement Accuracy of a Gaseous Fuel Injector

Accuracy of an injection rate measurement of a gaseous fuel injector was improved by modification of equations and static pressure correction. A production gaseous fuel injector for an NGV (Natural gas vehicle) was used, which is for an intake port fuel injection. The injection pressure was set at 255 kPa (g), and the injection duration was varied from 5 to 20 ms. Nitrogen gas was used as the test gas. The test gas was injected into a pipe from the injector, and the static pressure history was acquired with a piezoelectronic pressure transducer. One-dimensional, compressible, inviscid, adiabatic flow was assumed, and the instantaneous mass flow rate inside the pipe was estimated using newly modified equations. The pressure gradient due to pipe friction was corrected using Darcy-Weisbach equation. By integrating the injection rate during the injection duration, the total amount of mass flow per one stroke was calculated. The data obtained by the injection rate meter are compared to that of the calibration test, and it is shown that the injection rate measurement was carried out within the error of 2 to 3%

Radiation burden of assistant medical technicians at a medical accelerator.

A survey of a CLINAC 2100 C medical accelerator showed residual short half-life radiation after switching off the accelerator. This led to a dose of radiation for the medical employees when the patient was handled. The dose rate was measured with a dose rate meter FH40G, and annual dose for an assistant medical technician (AMT) was estimated under conservative conditions. In the assumed situation of 1000 patient treatment fractions with high-energy photons, an AMT would get an annual dose of 960 μSv, while the monthly dosimeter records would show zero, if the dose received is below threshold of 100 μSv.

Techniques employed for detection of hot particles in the marine environment

During the decommissioning of the Maine Yankee nuclear plant, several methods weredeveloped and employed to survey for hot particles in the marine environmentsurrounding the site. The methods used and the sensitivities achieved in the search forenvironmentally dispersed particles during the various decommissioning activitiesperformed are described in detail. Surveys were performed on dry soil, exposed marinesediment and submerged marine sediment. Survey techniques ranged from the use ofthe basic NaI detector coupled to a count rate meter to an intrinsic germaniumdetector deployed in a submarine housing coupled to a multi-channel analyser.The initial surveys consisted of collecting samples of marine sediment, spreading them out over a1 m2 surface in a thin layer, and scanning the deposited sediment by hand using a 5 cm by 5 cmNaI detector coupled to a standard count rate meter. This technique was later replaced bywalkover scans with the 5 cm by 5 cm NaI detector moved in a serpentine pattern overthe sediment surface. By coupling the detector to a ‘smart meter’, an alarm setpoint could be used to alert the surveyor to the presence of a particle within theinstrument’s field of view. A similar technique, with the detector mounted in awatertight housing secured to the end of a pole, was also employed to scan underwaterlocations. The most sensitive method developed for performing underwater surveyswas the use of the intrinsic germanium detector placed in a submarine housing.Detailed descriptions of the methods employed and the results obtained are presented. Thiswork demonstrates that there are several approaches to surveying for discreteparticles in the marine environment and the relative merits of each are considered.

Experimental Investigation of Spray and Combustion Characteristics of Dimethyl Ether in a Common-Rail Diesel Engine

Various characteristics of dimethyl ether (DME) as an alternative fuel for compression ignition engines were experimentally investigated including its spray characteristics, combustion performance, and emission reduction in a common-rail diesel engine. The spray behavior of DME was analyzed in terms of injection rate, spray development, and spray tip penetration, which were measured by an injection rate meter and a high-pressure spray chamber equipped with a spray visualization system. In addition, the engine performance and indicated mean effective pressure (IMEP), as well as exhaust emissions, including oxides of nitrogen (NOx), soot, hydrocarbons, and carbon monoxide were measured at various injection and operating cycle parameters. The combustion characteristics of DME fuel were compared with those of conventional diesel fuel in a diesel engine. Experimental results show that DME has an injection delay 0.03 ms shorter and a maximum injection rate 21% higher than those of diesel fuel at a constant injection pressure of 50 MPa and an injection mass of 8 mg/cycle. At a fixed energizing duration and injection pressure, a greater mass of DME was injected than that of diesel fuel. The DME-operated engine produced almost negligible soot emissions but also considerably higher NOx emissions than the engine operated with diesel fuel at a fixed IMEP.

Method for defined mass flow variations in time and its application to test a mass flow rate meter for pulsating flows

In a previous publication, the authors presented a transient mass flow rate metering technique for pulsating pipe flows and its outstanding performance was demonstrated experimentally for fuel injection nozzles. In the present paper, the application of the mass flow rate metering technique is described for pulsating air flows. The basics of the measuring technique are summarized and the corresponding experimental setup is explained. For verification experiments, a mass flow rate control unit was developed that permits time-varying mass flow rates to be provided proportional to the voltage of an electronic input signal to the unit. The basic ideas of this unit and its performance are summarized. Its application to verify the performance of the developed mass flow rate measuring instrument represents the major part of the paper. Performance tests were carried out for various time variations of mass flow rate pulsations. It is shown that the mass flow rate of the mean flow and that of the pulsating flow can be separated and both can be accurately measured. Comparative measurements show that the mass flow rate measuring technique works very well and reproduces the mass flow rate variations in time imposed by the mass flow rate control unit.

A neutron dose rate monitor for high energies

Neutron dose rate monitoring at neutron energies of several hundreds of MeV requires special instrumentation. Berthold Technologies has developed a new version of the widely used LB 6411neutron dose rate monitor for high energies, the LB 6411-Pb. A prototype was calibrated at the CERF at CERN in Geneva/Switzerland with neutron energies ranging up to 1 GeV. For comparison simultaneous measurements were made with a conventional LB 6411. The conventional neutron dose rate meter shows an underestimation, reporting only 68.9% of the reference dose. However, the results of the new version LB 6411-Pb with an additional lead layer of 10 mm thickness agree with the reference values by 98.8%. This shows that the new version is a promising candidate for neutron dose rate monitoring at high-energy accelerators.

MP-09.02: Development of a low cost urine flow rate meter for primary health care

MP-09.02: Development of a low cost urine flow rate meter for primary health care

Experimental Validation of a Common-Rail Injector Model in the Whole Operation Field

Abstract The present study deals with the definition of an accurate mathematical model of a production common-rail-type injector for automotive diesel engines. The mathematical model defined in a previous work was refined, accounting for a broader range of effects on injector performance, thus allowing a more strict validation of the model predictions against experimental data. The geometry of the control-valve holes, crucial in determining the actual discharge coefficient, was accurately evaluated by means of silicone molds. The moving mechanical components of the injector, such as control valve, needle, and pressure rod were modeled using the mass–spring–damper scheme. The axial deformation under pressure of needle, pressure rod, nozzle and injector body was modeled. This effect was found to also affect the control valve device operation, and was properly accounted for. The model obtained was implemented in Simulink; the ordinary differential equations were solved by means of the numerical differentiation formulas implicit scheme of second-order accuracy, while the partial differential equations were integrated using the finite-difference Lax–Friedrichs method. In order to obtain sufficient data for validating the model in its entire operation field, two separate sets of tests were carried out. In the first analysis, a constant reference pressure was imposed in the rail, and the injector energizing time was progressively increased from values relative to small pilot injections to values characteristic of large main injections. The injected volume per stroke was measured by means of a mean delivery meter (EMI) device. During the second set of tests, the injector was mounted on a flow rate meter (EVI) device so as to measure the injection law. Electric current flowing through the injector solenoid, oil pressure in the common rail, and at the injector inlet, needle, and control valve lift were also gauged and recorded. The good agreement between numerical and experimental results allowed the use of the model to gain greater insight into the mechanisms and phenomena that regulate injector behavior. The nozzle hole discharge coefficient dependence upon time and needle lift was discussed, and the trends were presented in several working conditions. The flow in the control volume holes was studied, in order to determine whether cavitation occurs or not, giving an answer to a long disputed topic. Finally, the effects of injector deformation caused by fuel pressure on performance were investigated.

The workload of riding‐school horses during jumping

As there are no reports on the real workload of horses that jump fences, this study was undertaken in riding-school horses. To compare the workload of horses jumping a course of fences with that of horses cantering over the same course at the same average speed without jumping fences. The workload variables included heart rate (HR), packed cell volume (PCV), acid-base balance (venous pH, pCO2, HCO3-) and blood lactate (LA), glucose, total protein and electrolyte concentrations. Eight healthy riding-school horses performed test A (a course of approximately 700 m with 12 jumps from 0.8-1.0 m high at an average speed of approximately 350 m/min) and test B (same course at the same speed, but without the rails) in a crossover study with at least 4 h between the 2 tests. Before each test the horses were fitted with a heart rate meter (Polar Electro). Blood samples were taken from the jugular vein at rest prior to the test, after warm-up before starting the course, immediately after the course and after recovery. All samples were analysed immediately. The mean +/- s.d maximal HR (beats/min) during the course (184 +/- 17 and 156 +/- 21, respectively) and the mean HR after recovery (75 +/- 6 and 63 +/- 7, respectively) were significantly higher in test A compared to test B (P = 0.001 and P = 0.007 respectively). The mean LA concentrations after the course and after recovery (mmol/l) were significantly higher in test A (3.6 +/- 2.7 and 1.0 +/- 0.9, respectively) compared to test B (0.9 +/- 0.5 and 0.3 +/- 0.1, respectively), (P = 0.016 and P = 0.048 respectively). The mean PCV (I/l) after the course and after recovery was also significantly different between tests A (0.48 +/- 0.04 and 0.39 +/- 0.03, respectively) and B (0.42 +/- 0.04 and 0.36 +/- 0.03, respectively) (P<0.01). The mean pH and the mean HCO3- (mmol/l) after the course were significantly lower in test A (7.40 +/- 0.04 and 28.9 +/- 1.4, respectively) compared to test B (7.45 +/- 0.03 and 30.4 +/- 2.3, respectively) (P<0.05). This study indicates that in riding-school horses jumping fences, even at a low level competition, provokes a significant workload compared to cantering the same distance and speed without fences. This study makes it clear that the extra workload of jumping fences should be taken into account in the training programmes of jumping horses. Further research with more experienced horses jumping higher fences will reveal the workload for top-level jumping horses.

SU-FF-T-237: Exposure Rate Calculation: Effect Of Photon Divergence Near A Radioactive Source

The objective is to show that near a radioactive source the commonly used exposure rate equation has to be modified in order to take photon divergence into consideration. This is accomplished by showing the derivation of the standard equation in detail and then illustrating where photon divergence needs special consideration. The commonly used equation for calculating the exposure rate is Eq.1 and the modified equation Eq.2. The reason for the modification is that the irradiated volume per unit entrance area is larger at close proximities. This means that charge produced per unit volume per photon penetrating the entrance area is smaller at close proximities than at a distance. Since the exposure is defined as charge liberated per unit volume or unit mass of air this results in Eq.1 overestimating the exposure rate. This is of relevance (a deviation of 10% or more between expected and measured value) at distance smaller than 5 cm. At larger distances the difference between both equations becomes negligible. An experiment using a Tc‐99m point source and a calibrated exposure rate meter is performed to compare theoretical and experimental values and to show the difference between the predictions of the two equations. This comparison showed very good agreement of the measured values and the predicted values based on Eq.2 and an overestimation of the exposure rate calculated using Eq.1. This has also implications for the tabulation of Gamma factors ( ) and their units: (mR⋅cm∧2)/(mCi⋅hr) vs. (mR⋅cm∧3)/(mCi⋅hr). Eq. 1 : Ẋ [ mR hr ] = Γ Activity dis tan ce 2 Eq. 2 : Ẋ [ mR hr ] = Γ 3 Activity (dis tan ce + 1) 3 − dis tan ce 3 .

BND (bubble number density) decompression rate meter for explosive volcanic eruptions

This decade has been witness to substantial progress in the understanding of bubble dynamics and its role in volcanic eruptions. A comparison between the results of experiments and a model for bubble nucleation shows that bubble number density (BND) can be calculated as a function of decompression rate for given physical properties, such as the diffusivity of water in a silicate melt and interfacial tension, within an acceptable margin of error. Conversely, in this paper, we propose a method (hereafter referred to as BND decompression rate meter) to estimate the decompression rate by using BND data of natural pumice samples from volcanic eruptions. As a result of the application of the BND decompression rate meter to pumice and scoria from explosive eruptions, it is found that the decompression rates increase in the range from 10 6 to 10 8 (Pa/s) with the eruption column heights; these rates are proportional to the 4th power of the eruption column heights and are linear to the discharge rates. The absolute values of the estimated decompression rates are very high and cannot be explained by the existing models of conduit flows. In order to explain such high rates of decompression and the correlation with discharge rate, we propose a possible model according to which the bubble nucleation propagates downward as a rarefaction shock wave in the conduit.

Effect of Injector Type on Fuel-Air Mixture Formation of High-Speed Diesel Sprays

This study was performed to analyse the characteristics of fuel sprays issued from a piezo-driven injector and to compare both experimental results and numerical predictions with those from a solenoid-driven injector. In order to study the effect of the injector type, two injectors with the same specifications - except for their drive type - were used in the experiments. In this work, the profiles of injection rates, processes of spray development, mean droplet size distributions, and mean velocities were obtained using an injection rate meter, a spray visualization system, and a phase Doppler particle analyser (PDPA) system. In order to calculate the atomization process of the injected spray, the Kelvin-Helmholtz instability/droplet deformation and break-up ((KH-DDB) model was used, and the prediction accuracies were verified by comparing them with experimental results. For the numerical approach using the KIVA code, the nozzle flow and droplet break-up models were modified to consider the conditions of a common-rail injection system. The input parameters for the KIVA calculations were determined based on the nozzle flow model considering the effect of cavitation. In addition, the effects of injector type on the evaporation characteristics were calculated using the modified Spalding evaporation model. This study reveals that the injection delay of the piezo-driven injector is shorter than that of the solenoid-driven injector by 0.06 ms, and that the atomization and evaporation performances of the fuel spray can be enhanced by using the piezo injector instead of the solenoid injector.

Evidence for p-process nucleosynthesis recorded at the Solar System abundances

Analyzing the Solar System abundance, we have found two universal scaling laws concerning the p- and s-nuclei with the same atomic number. They are evidence of the p-nucleus origin that has been discussed for long years. The first scaling is the correlation of the isotope abundances between a p-nucleus and an s-nucleus that is two neutron heavier than the p-nucleus. The abundance ratios of the s-nucleus to the p-nucleus are almost constant in a wide range of atomic numbers. This scaling indicates that the p-nucleus is dominantly produced from the s-nucleus by (γ, n) reactions in huge photon bath in supernova explosions. The second scaling indicates that the isotope abundance ratio between two p-nuclei with the same atomic number is almost unity. These two scalings are a new useful method to verify nucleosynthesis models for the p-process. We have calculated these ratios by a p-process nucleosynthesis based on a typical core-collapse supernova explosion model. The results are consistent with the scaling in the solar abundances. In addition, the scalings provide new concepts: a universality of the p-process, a rate meter for the s-process and a new nuclear cosmochronometer.

Count rate meter with a time constant using adaptive digital signal processing

Two methods developed to improve the classical time constant count rate meters by using the adaptive signal-processing tools are presented. An optimized detection algorithm that senses the change of the mean count rate was implemented in both methods. Three different types of low-pass filters of various structures with adaptive parameters to implement the control of the mean count rate error by suppressing the fluctuations in a controllable way were considered, and one of them was implemented in both methods. An adaptation algorithm for time constant interval calculation was executed after the low-pass filter was devised and implemented in the first method. This adaptation algorithm makes it possible to obtain shorter time constant intervals for higher stationary mean count rates. The adaptation algorithm for time constant interval calculation executed before the low-pass filter was devised and implemented in the second method. This adaptation algorithm enables sensing of the rapid change of the mean count rate before the fluctuations suppression is carried out. Some parameters were fixed to their optimum values after appropriate optimization procedures had been performed. The implemented low-pass filter has variable number of stationary coefficients depending on the specified error and the mean count rate. It implements the control of the mean count rate error by suppressing the fluctuations in a controllable way. The simulated and realized methods, using the developed algorithms, guarantee: a response time not in excess of 2 s for a mean count rate higher than 2 counts/s and a controllable mean count rate error in the range of 4–10%.

Some practical realizations of preset time count rate meters using optimized adaptive digital signal-processing solutions

Two optimized adaptive digital signal processors were developed to implement the preset time count rate meters. The first processor improves stationary characteristics of the count rate meter by implementing the control of the error of the mean count rate when the changes of the mean count rate are only due to its stochastic nature. The second processor is focused on dynamic characteristics. Its time response is made adaptive to the changes of the mean count rate which are due to increased or decreased radiation levels. The change of the mean count rate is sensed by a specially devised detection algorithm. Three mean count rate meters, based on the developed adaptive digital signal processors, were realized and were used for experimental validation of proposed adaptive digital signal processors. The experimental results, conducted without and with radioisotope for the specified errors of 10% and 5%, showed to agree well with theoretical predictions.

NORM Contamination—Now You See It, Now You Don’t

Contamination from naturally occurring radioactive material on the inside of piping or tanks in refineries can usually be easily detected from the outside by external gamma measurements with simple count rate meters or more complicated gamma spectroscopy instruments. Usually, such contamination is from radium in equilibrium with its progeny. A number of different gamma rays are emitted by this mix. However, due to certain processes or circumstances, a significant amount of NORM can be present without the characteristic gamma signature of radium and its progeny. The process of cracking low molecular weight hydrocarbon gases from crude oil allows radon through but leaves radium behind. The radon enters the process piping and decays, depositing its short-lived decay products or progeny. When the short-lived progeny decay, all that is left are alpha and beta emitters. When this occurs, measurements taken on the outside of piping indicate no elevated levels of gamma radiation; however, elevated levels of alpha and beta radiation can be detected on the inside of the piping. 210Pb is usually the only gamma emitter detected on the inside of the piping and, its gamma ray energy is such that little if any penetrates the walls of the piping. Since one of the release criterion for piping material is an external dose rate of less than 50 microR h(-1), it is possible that a survey from the outside of the piping can be negative when, in fact, thee can be appreciable contamination on the inside of the piping.

A method of dead time measurement

A practical method for the dead time measurement of a counting system is proposed. The method is based on the irradiation of a counting system in the reference photon field for the calibration of dosimeters or dose rate meters. Using the method, we measured the dead time of a GM counting system.

A HISTORY OF RADIATION DETECTION INSTRUMENTATION

A review is presented of the history of radiation detection instrumentation. Specific radiation detection systems that are discussed include the human senses, photography, calorimetry, color dosimetry, ion chambers, electrometers, electroscopes, proportional counters, Geiger Mueller counters, scalers and rate meters, barium platinocyanide, scintillation counters, semiconductor detectors, radiophotoluminescent dosimeters, thermoluminescent dosimeters, optically stimulated luminescent dosimeters, direct ion storage, electrets, cloud chambers, bubble chambers, and bubble dosimeters. Given the broad scope of this review, the coverage is limited to a few key events in the development of a given detection system and some relevant operating principles. The occasional anecdote is included for interest.

SU‐FF‐T‐23: Comparison of Chest Radiographs, Fluoroscopy and Seed‐Migration Detector for the Detection of Embolized Seeds to the Lung

Purpose: To evaluate the efficacy of a seed‐migration detector and to compare its performance to fluoroscopy and to the postoperative chest radiographs generally recommended. Method and Materials: A low energy gamma scintillation survey meter, used together with a count rate meter, was converted to a seed‐migration detector. The detector was used to perform a chest evaluation on 155 patients (8717 seeds) at their first postoperative visit. When the detector showed activity around a patient s chest, it was confirmed by taking an antero‐posterior chest radiograph and by looking at the region with fluoroscopy. Results: 33 patients (21.3%) present at least one embolized seed. That is a 0.47% seed migration rate (41/8717). 37 (90%) of the seeds were visible under fluoroscopy and 28 (68%) appeared on x‐rays. Rapid movement of the seeds, due to breathing or to a location close to the heart or the diaphragm, makes nine seeds to be visible with fluoroscopy but not on the radiograph. Moreover, four seeds were not visible with fluoroscopy neither with radiograph. In comparison to the seed‐migration detector, detection based on fluoroscopy would have led to four false‐negative detections (out of 33 or 12.1%) while the radiograph would have resulted in thirteen (out of 33) false‐negative detections or 39.4%. Finally, standard chest x‐ray would have required a survey, and extra radiation dose to lung, to 100% of the patients rather than the 21.3% who needed it in this study. Conclusion: Because of the high false‐negative rate and the superior efficacy of a scintillator‐based seed‐migration detector, the usual recommendation to perform chest radiographs should be revised. X‐rays should remain for documentation purposes of positive cases only. Our clinical experience also allowed us to conclude that the detector is convenient, cost‐effective and non‐invasive, meaning that it does not require any additional radiation to the patient.