Neutron monitors detect secondary particles produced by the collision of cosmic rays and atmospheric nuclei. The need exists for a mini-neutron monitor data acquisition system (MNM-DAS) to replace the existing recording system of the calibration neutron monitor developed in 2003 at the North-West University Centre for Space Research. The MNM-DAS must also replace the recording system of a standard NM64 neutron monitor. This research thus includes the development of the MNM-DAS using Design Science Research (DSR) in conjunction with Systems Engineering (SE) to streamline the design phase and maximize research output. A literature study is conducted, where an overview of the calibration monitor system is provided, together with the objectives for the development of the MNM system. An abstract system architecture was drawn up in the conceptual design phase of the project to provide a coherent description of all system functions. The system architecture was derived for the existing system, including additional functions of the required system, by performing a functional analysis. The architecture describes the function and fit of each functional unit and all interfaces that form an integrated system. From the conceptual design and system architecture, a preliminary synthesis was done. Following the preliminary synthesis, electronic circuitry was developed to capture the arrival time of pulses from the proportional neutron monitor counter tubes along with environmental variables, such as temperature, pressure, and location, which all influence the count rate. The MNM-DAS was successfully designed and developed by following this Systems-Engineering approach embedded into a Design Science Research framework. The MNM-DAS was constructed and tested, and is currently being used to provide neutron count data in real-world applications internationally. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014

Livestock and companion animals are valuable economically and emotionally in the economy of many states and to their citizens. In a radiological emergency situation, the loss of a large amount of livestock could be devastating to a state or national economy. If such an event occurred, there are currently no screening and decontamination protocols for the handling of livestock. This research investigated current policies and procedures for monitoring and decontamination of livestock and companion animals, as well as testing pedestrian portal monitors and a newly designed livestock portal capable of radionuclide identification. It was discovered that only ten states addressed companion animals or livestock anywhere in their emergency planning. Of the ten, only North Carolina, Washington, and a Massachusetts K9 unit had detailed decontamination procedures to report for companion animals. None of the states included detailed procedures for livestock. To address livestock screening, three pedestrian portal monitoring systems were tested in the field and lab trials – the Johnson AM801, TSA TPM903A, and Ludlum 52-1-1. The systems were tested for position and count rate sensitivity with 1 and 5 µCi 137Cs sources placed on four locations on a steer. Factors such as operability and ease of use were also considered. All three systems would alarm when a 5 µCi 137Cs source was used and the occupancy sensor was triggered. The Johnson AM801 system was determined to be the most appropriate for use in livestock screening due to sensitive alarm algorithms, greater position discrimination with four detectors, and ease of adjustment for agricultural purposes. The last phase of this project included designing and constructing a portal system that included radionuclide identification capabilities. An array of six sodium iodide detectors was mounted on a panel and field-tested beside a cattle chute and in a walkway. The custom portal, the Bovine Screening Portal (BSP), observed increased count rates (>10σ) from a 5 µCi 137Cs source in live time. The BSP demonstrated better detection and localization of the source and spectral identification capabilities compared to the commercially available pedestrian systems.

One of two project reports. The other is designated PART A: McMASTER (ON-CAMPUS) PROJECT / <p> It is well known that heart rate is an important physiological parameter. In some cases, continuous monitoring of active subjects is desireable. </p> <p> The report focuses on the feasibility of a miniaturized, portable heart rate monitor. Good artifact rejections, low power consumption small size and ease of use are of primary importance in such design. In order to keep size as low as possible a single cell (1 .5 V) supply voltage is used. </p> <p> A LED - phototransistor type of transducer was chosen for its good artifact rejection and simplicity of application. The transducer clips on the subject's earlobe. Light transmitted through the earlobe is amplitude modulated by the heart (blood) pulses and detected by the phototransistor thus providing electrical signal. </p> <p> In order to keep current drain low, the LED was powered by ~ 1% duty cycle pulses. The rest of the system was designed to comply with the requirements of the transducer. The detected train of pulses were preamplified and the original modulating waveform (heart pulse) reconstructed by a "sample and hold" circuit. The reconstructed signal was amplified by a narrow-band-pass amplifier filter. </p> <p> An astable and two monostable multivibrators perform the necessary timing. Two integrated circuits were also employed: a voltage regulator, to provide stable reference voltages where needed and the output amplifier filter, providing the bulk of the gain. </p> <p> A working prototype was built and suggests that a personalized heart rate monitor is quite feasible. The whole circuit can be integrated, with the exception of few capacitors and perhaps some trimming potentiometers. </p> / Thesis / Master of Engineering (MEngr)

Impedance pneumography is a non-invasive and a very convenient technique for monitoring breathing. However, a major drawback of this technique is that it is impossible to monitor breathing due to large artefacts introduced by the body movements. The aim of this project was to develop a technique for reducing these 'movement artefacts'. In the first stage of the project, experimental and theoretical studies were carried out to identify an 'optimum' electrode placement that would maximise the 'sensitivity' of measured thoracic impedance to lung resistivity changes. This maximum sensitivity was obtained when the drive and the receive electrode pairs were placed in two different horizontal planes. This sensitivity was also found to increase with increase in electrode spacing. In the second stage, the optimum electrode placement was used to record thoracic impedance during movements. Movement artefacts occurred only when the electrodes moved from their initial location along with the skin, during movements. Taking into consideration these observations, a strategy was decided for placing 4 electrodes in one plane so that movement artefacts could be reduced by combining the two independent measurements. Further studies showed that movement artefacts could be reduced using a strategic 6- electrode placement in three dimensions. It was also possible to detect obstructive apnoea, as the amplitude of the breathing signal was higher than that due to obstructive apnoea and this difference was statistically significant. In these studies, the main cause of movement artefacts was identified as the movement of electrodes with the skin. A significant reduction in movement artefacts was obtained using the 6-electrode placement. This advantage of the 6-electrode placement proposed in this project, can be of great use in clinical applications such as apnoea monitoring in neonates. Further studies can be carried out to determine an optimum frequency of injected current to achieve reduction in residual movement artefacts.

The Multi-Isotope Process Monitor is being developed at Pacific Northwest National Laboratory as a method to verify the process conditions within a nuclear fuel reprocessing facility using the gamma spectra of various process streams. The technique uses multivariate analysis techniques such as principal component analysis and partial least squares regression applied to gamma spectra collected of a process stream in order to classify the contents as belonging to a normal versus off-normal chemistry process. This approach to process monitoring is designed to function automatically, nondestructively, and in near real-time. To extend the Multi-Isotope Process Monitor, an analysis method to char- acterize spent nuclear fuel based on the reactor of origin, either pressurized or boiling water reactor, and burnup of the fuel using nuclide concentrations as input data has been developed. While the Multi-Isotope Process Monitor uses gamma spectra as input data, nuclide activities were used in this work as an initial step before Nuclide composition information was generated using ORIGEN-ARP for different fuel assembly types, initial 235U enrichments, burnup values, and cooling times. This data was used to train, tune, and test several multivariate analysis algorithms in order to compare their performance and identify the technique most suited for the analysis. To perform the classification based on reactor type, four methods were considered: k-nearest neighbors, linear and quadratic discriminant analysis, and support vector machines. Each method was optimized, and its performance on a validation set was used to determine the best method for classifying the fuel reactor class. Partial least squares was used to make burnup predictions. Three models were generated and tested: one trained on all the data, one trained for just pressurized water reactors, and one trained for boiling water reactors. Quadratic discriminant analysis was chosen as the best classifier of reactor class because of its simplicity and its potential to be extended to classify spent nuclear fuel’s fuel assembly type, i.e, more specific classes, using nuclide concentrations as input data. In the case of predicting the burnup of spent fuel using partial least squares, it was determined that making reactor-specific partial least squares models, one trained for pressurized water reactors and one trained for boiling water reactors, performed better than a single, general model that was trained for all light water reactors. Thus, the the classifier, regression algorithm, and all the necessary intermediate data processing steps were combined into a single analysis method and implemented as a Matlab function called “burnup.” This function was used to test the analysis routine on an additional set of data generated in ORIGEN-ARP. This dataset included samples with parameters that were not represented in the development data in order to ascertain the analysis method’s ability to analyze data for which it has not been explicitly trained. The algorithm was able to achieve perfect binary classification of the reactor as being a pressurized or boiling water reactor on the dataset and made burnup predictions with an average error of 0.0297%. / text

Irradiadores comerciais de grande porte são projetados para processarem grandes quantidades de produtos com altas doses, por exposição à radiação gama. A irradiação em escala industrial é efetuada de forma dinâmica, em que os produtos percorrem um caminho em torno de uma fonte de radiação, geralmente de 60Co, cuja atividade é da ordem de TBq a PBq (kCi a MCi). A dose será diretamente proporcional ao tempo transcorrido pelo material para percorrer este trajeto em torno da fonte. Entretanto, em algumas situações, principalmente para pesquisas ou processos de validação de clientes seguindo a norma ISO 11137, se faz necessário irradiar pequenas amostras com doses fracionadas na posição de irradiação estática. Nesta posição as amostras são colocadas dentro da sala de irradiação a uma distância fixa da fonte e as doses recebidas são determinadas utilizando-se dosímetros. Portanto, a dose somente será conhecida depois da irradiação, pela leitura dos mesmos. Entretanto, em irradiadores industriais, diferentes tipos de produtos com diferentes densidades atravessam o caminho entre a fonte e a posição de irradiação estática, onde estão as amostras. Conseqüentemente, a taxa de dose variará dependendo da densidade do produto, que está sendo irradiado dinamicamente. Uma metodologia adequada seria monitorar a dose recebida pelas amostras em tempo real, medindo a dose por meio de um detector de radiação, com uma melhor precisão e exatidão. Neste trabalho foi desenvolvida uma câmara de ionização cilíndrica de 0.9 cm3, para monitorar as altas doses recebidas por amostras em tempo real, na posição de irradiação estática de um irradiador gama de 60Co. Os gases de nitrogênio e de argônio a pressão de 10exp5 Pa (1 bar) foram utilizados para preencherem a câmara de ionização e determinar uma configuração de trabalho apropriada, para o detector ser utilizado em medidas de altas doses. Cabos de isolação mineral foram soldados diretamente ao corpo da câmara de ionização, para a transmissão do sinal gerado pelo detector até a eletrônica associada, distante cerca de 20 m. O sinal obtido foi cerca de 100 vezes maior do que o ruído de fundo. Este sistema dosimétrico foi testado em um irradiador gama de categoria I e na posição de irradiação estática de um irradiador de grande porte, em que diferentes taxas de dose foram obtidas utilizando materiais absorvedores. Foi encontrada uma boa linearidade do detector entre a dose e a carga, independentemente das diferentes taxas de dose. As incertezas de todas as curvas ficaram abaixo dos +/- 5 %, valor de incerteza máxima recomendada para um sistema dosimétrico de rotina. A câmara de ionização desenvolvida se mostrou adequada para ser utilizada como um dosímetro em tempo real, independente da degradação do espectro causada pela absorção dos fótons da fonte de 60Co, pelo material em irradiação dinâmica. / Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60Co gamma source with activity of TBq to PBq (kCi to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60Co gamma industrial plant. Nitrogen and argon gas at pressure of 10exp5 Pa (1bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma irradiator and at an industrial irradiation plant in static position, using different absorbing materials. A good linearity of the detector was found between the dose and the accumulated charge, independently of the different dose rates caused by absorbing materials. The uncertainties for all curves were less than 5%, which is recommended for a dosimetric system routine. The developed ionization chamber showed to be suitable as a dosimeter on line, independently of the spectrum degradation caused by the absorption of the 60Co photons in the material under dynamic irradiation.

Irradiadores comerciais de grande porte são projetados para processarem grandes quantidades de produtos com altas doses, por exposição à radiação gama. A irradiação em escala industrial é efetuada de forma dinâmica, em que os produtos percorrem um caminho em torno de uma fonte de radiação, geralmente de 60Co, cuja atividade é da ordem de TBq a PBq (kCi a MCi). A dose será diretamente proporcional ao tempo transcorrido pelo material para percorrer este trajeto em torno da fonte. Entretanto, em algumas situações, principalmente para pesquisas ou processos de validação de clientes seguindo a norma ISO 11137, se faz necessário irradiar pequenas amostras com doses fracionadas na posição de irradiação estática. Nesta posição as amostras são colocadas dentro da sala de irradiação a uma distância fixa da fonte e as doses recebidas são determinadas utilizando-se dosímetros. Portanto, a dose somente será conhecida depois da irradiação, pela leitura dos mesmos. Entretanto, em irradiadores industriais, diferentes tipos de produtos com diferentes densidades atravessam o caminho entre a fonte e a posição de irradiação estática, onde estão as amostras. Conseqüentemente, a taxa de dose variará dependendo da densidade do produto, que está sendo irradiado dinamicamente. Uma metodologia adequada seria monitorar a dose recebida pelas amostras em tempo real, medindo a dose por meio de um detector de radiação, com uma melhor precisão e exatidão. Neste trabalho foi desenvolvida uma câmara de ionização cilíndrica de 0.9 cm3, para monitorar as altas doses recebidas por amostras em tempo real, na posição de irradiação estática de um irradiador gama de 60Co. Os gases de nitrogênio e de argônio a pressão de 10exp5 Pa (1 bar) foram utilizados para preencherem a câmara de ionização e determinar uma configuração de trabalho apropriada, para o detector ser utilizado em medidas de altas doses. Cabos de isolação mineral foram soldados diretamente ao corpo da câmara de ionização, para a transmissão do sinal gerado pelo detector até a eletrônica associada, distante cerca de 20 m. O sinal obtido foi cerca de 100 vezes maior do que o ruído de fundo. Este sistema dosimétrico foi testado em um irradiador gama de categoria I e na posição de irradiação estática de um irradiador de grande porte, em que diferentes taxas de dose foram obtidas utilizando materiais absorvedores. Foi encontrada uma boa linearidade do detector entre a dose e a carga, independentemente das diferentes taxas de dose. As incertezas de todas as curvas ficaram abaixo dos +/- 5 %, valor de incerteza máxima recomendada para um sistema dosimétrico de rotina. A câmara de ionização desenvolvida se mostrou adequada para ser utilizada como um dosímetro em tempo real, independente da degradação do espectro causada pela absorção dos fótons da fonte de 60Co, pelo material em irradiação dinâmica. / Industrial gamma irradiators facilities are designed for processing large amounts of products, which are exposed to large doses of gamma radiation. The irradiation, in industrial scale, is usually carried out in a dynamic form, where the products go through a 60Co gamma source with activity of TBq to PBq (kCi to MCi). The dose is estimated as being directly proportional to the time that the products spend to go through the source. However, in some situations, mainly for research purposes or for validation of customer process following the ISO 11137 requirements, it is required to irradiate small samples in a static position with fractional deliver doses. The samples are put inside the irradiation room at a fixed distance from the source and the dose is usually determined using dosimeters. The dose is only known after the irradiation, by reading the dosimeter. Nevertheless, in the industrial irradiators, usually different kinds of products with different densities go through between the source and the static position samples. So, the dose rate varies in function of the product density. A suitable methodology would be to monitor the samples dose in real time, measuring the dose on line with a radiation detector, which would improve the dose accuracy and avoid the overdose. A cylindrical ionization chamber of 0.9 cm3 has been developed for high-doses real-time monitoring, during the sample irradiation at a static position in a 60Co gamma industrial plant. Nitrogen and argon gas at pressure of 10exp5 Pa (1bar) was utilized to fill the ionization chamber, for which an appropriate configuration was determined to be used as a detector for high-dose measurements. To transmit the signal generated in the ionization chamber to the associated electronic and processing unit, a 20 m mineral insulated cable was welded to the ionization chamber. The signal to noise ratio produced by the detector was about 100. The dosimeter system was tested at a category I gamma irradiator and at an industrial irradiation plant in static position, using different absorbing materials. A good linearity of the detector was found between the dose and the accumulated charge, independently of the different dose rates caused by absorbing materials. The uncertainties for all curves were less than 5%, which is recommended for a dosimetric system routine. The developed ionization chamber showed to be suitable as a dosimeter on line, independently of the spectrum degradation caused by the absorption of the 60Co photons in the material under dynamic irradiation.

Invasive and non-invasive methods of BTI monitoring and wearout preemption have been proposed. We propose a novel, simple to use, test structure for NBTI /PBTI monitoring. The proposed structure has an AC and a DC stress mode. Although during stress mode, both PMOS and NMOS devices are stressed, the proposed structure isolates the PBTI and NBTI degradation during test mode. A methodology of converting any data-path into ring oscillator (DPRO) is also presented. To avoid the performance overhead of attaching monitoring circuitry to functional block, a non-invasive scheme for BTI monitoring is presented for sleep transistor based logic families. Since, BTI is a critical issue for memories, a scheme for BTI monitoring of 6T SRAM cell based memories is also presented. We make use of the concept of a DPRO and show how a memory system can be made to oscillate in test mode. The frequency of oscillation is a function of the devices in the cell. After validation of the proposed schemes using extensive simulations, we have also validated the results on silicon. We also introduce the concept of wearout mitigation at the compiler level. Using an example of a register file, we present a preemptive method of wearout mitigation using a compiler directed scheme.

Electrocardiography (ECG) monitor is a medical device for recording the electrical activities of the heart using electrodes placed on the body. There are many ECG monitors in the market but it is essential to find the accuracy with which they generate results. Accuracy depends on the processing of the ECG signal which contains several noises and the algorithms used for detecting peaks. Based on these peaks the abnormality in the functioning of the heart can be estimated. Hence this thesis characterizes the ECG signal which helps to detect the abnormalities and determine the accuracy of the system.

Atmospheric aerosol particles also known as atmospheric particulate matter or particulate matter (PM) are microscopic particles (solid or liquid) suspended in air, which is one of six air pollutants in US air quality standard. PM is classified as coarse particles with diameters between 2.5 to 10 mm, fine particles with a diameter less than 2.5 mm (PM2.5), and ultrafine particles with the diameter less than 0.1 mm (PM0.1). Epidemiological studies have already showed the adverse health effects (such as asthma, lung cancer and respiratory and cardiovascular disease) resulted from exposure to the fine and ultrafine particles. Monitoring the PM concentration (i.e., either mass or surface area concentration of PM) is critical for the protection of public health and environment and for the regulatory control. Various PM sensors are now available in market. A majority of these PM sensors are optical sensors, whose readouts are highly depended on the physical property and composition of PM. Several PM monitors based on the measurement principle of electrical charging are also available. However, the empirical calibration of the readout of these electrical PM monitors via the use of standard dust particles makes it difficult to obtain the true mass concentration of PM when PM size distribution is different from that of standard dust. The overall objective of this dissertation is to advance our scientific knowledge on the performance of cost-effective PM monitors for measuring either mass or surface area concentration of fine and ultrafine PM. This thesis includes two parts: (1) is on the evaluation of existing PM sensor for PM mass concentration measurement; (2) is on the development of new PM monitor for PM surface area concentration measurement. For the first part of this dissertation, four low-cost optical sensors, one Personal Dust Monitor (PDM) and DustrakTM were experimentally evaluated. Particles in the size distribution having different mean size, standard deviation value and material were used as test aerosol particles. The readouts of these low-cost and portable sensors are compared to that of a standard TEOM (Tapered Element Oscillation Microbalance). For the second part of this dissertation, a new electrical PM monitor, consisting of a corona-based aerosol charger, a precipitator and high sensitive current meter, has been proposed for measuring surface area concentration of fine and ultrafine PM. Particles are electrically charged upon entering an electrical PM monitor. Instead of using Faraday cage and current meter to measure the charges carried by particles in existed electrical PM sensors, the new PM monitor measures the current carried by particles deposited directly on the wall of the precipitator. A thorough evaluation has been carried out to evaluate the fundamental performance of this new PM monitor. In addition, small cyclones (i.e., quadru-inlet and tapered-body cyclones) were also evaluated as the size-selective inlet of these PM sensors/monitors to minimize the potential interface from the presence of PM with large sizes in the air. The small quadru-inlet cyclone is to resolve the issue of directional sampling; and the tapered-body cyclones is to reduce the cyclone pressure drop while having small cyclone cutoff particle size. Each cyclone has been evaluated via the measurement of particle penetration curve and pressure drop. Semi-empirical models have been obtained for the prediction of cyclone performance.