Concrete is among the most common materials utilized to construct protective elements in hardened structures. Subsequently, understanding how a concrete member will respond to explosively driven fragment or projectile impact is critical to the protective design process. Explosively driven fragments can have many different shapes and sizes depending on the event that resulted in their creation. These geometric variations can include a high-aspect, or width to thickness, ratio; however, impact from fragments with elevated aspect ratios on hardened concrete has not been extensively studied. Therefore, reinforced concrete specimens were subjected to impact from fragments with different aspect ratios to illustrate and quantify the effect of fragment characteristics, protective element features, and experimental target size on local impact performance. A novel experimental technique was developed to allow for high-aspect ratio fragment impact on concrete slabs to be evaluated. The same concrete materials were also impacted with lower aspect ratio fragments for comparative purposes. Data collected from these two experimental series were utilized to analyze the effects of compressive strength, thickness, and fiber reinforcement on impact performance. The accuracy of existing penetration and spall prediction methodologies were evaluated for both fragment types. The kinetic energy required to cause reinforced concrete to present a breached condition due to the high-aspect ratio fragment was also analyzed. Modifications were made to existing contact charge equations to account for differences between the contact charge energy required to cause a breach condition and that required from fragment impact to produce a breach condition. The breach envelope defined by these relationships was further evaluated using a computational model calibrated specifically for this impact scenario. Finally, the effect of impact specimen geometry and confinement type on target performance was numerically evaluated. Artificial and inertial confinement were examined through varying target diameter to projectile diameter ratio with and without artificial circumferential confinement. Given the minimal data associated with local effects of high-aspect ratio fragment impact and the many factors that can influence concrete impact resistance, the information and relationships learned along with the analysis techniques developed herein can be utilized to improve the state of the art of protective design.

Trots att det har utvecklats skyddsutrustning som skyddar hjärnan mot farlig roterande kinematik inom flera områden, finns ännu ingen utrustning som skyddar boxare mot den typen av våld. Syftet med arbetet var att göra olympisk boxning och träning säkrare. Målet var att utveckla en handske som reducerar töjningen i hjärnan med minst 20 %. I det här arbetet utvecklades och testades ett antal boxningshandskar med implementerade glidskikt som skulle reducera töjningen i hjärnan som uppstår när huvudet utsätts för roterande kinematik. Testerna genomfördes med en linear impactor som slog handskarna mot ett testhuvud. Testhuvudet samlade mätdata med hjälp av nio accelerometrar. Två av prototyperna reducerade töjningen med mer än 20 % vid ett eller flera tester men de hade brister i användningsbarhet. Ingen av prototyperna uppfyllde alla mål och därför kan ingen prototyp rekommenderas för vidareutveckling men det kan konstateras att det finns potential i grundidén. / Although protective equipment has been developed that protects the brain against dangerous rotating kinematics in several areas, no equipment is yet available to protect boxers against this type of violence. The purpose of this work was to make Olympic boxing and training safer. The goal was to develop a glove that reduces the strain in the brain by at least 20 %. In this work, a number of boxing gloves with implemented sliding layers were developed and tested, which would reduce the strain in the brain that occurs when the head is subjected to rotational kinematics. In the tests a linear impactor was used, which hit the gloves against a test head. The test head collected data using nine accelerometers. Two of the prototypes reduced the strain by more than 20% in one or more tests, but they lacked in usability. None of the prototypes met all objectives and therefore no prototype can be recommended for further development, but it can be stated that there is potential in the basic idea. / <p>Betyg 2020-07-11</p>

Recent instrument development for aerosol measurement has focussed on small-scale, on-line measurements that can be incorporated into miniaturised sensor nodes as part of ambient or personal air quality monitoring networks. As a result, optical particle counters (OPCs) have risen in popularity given their ability to consistently size and count individual particles. OPCs have limitations, however, in their inability to detect ultrafine particles (considered the most influential to human health) or to measure particle mass directly (the standard metric for air quality). The growing field of microelectromechanical systems (MEMS) offers a potential alternative by implementing microresonators as mass sensors. MEMS resonators have high mass sensitivities and have recently seen implementation as particulate matter (PM) monitors. The field of MEMS PM instruments is still limited with a variety of implemented resonator topologies and sampling mechanisms. In general, however, they offer real-time, high sensitivity measurements at low flow rates. The aim of this thesis was to further examine the viability of implementing MEMS resonators for PM measurement with a focus on practical considerations for real-world applications. To this end, a new microresonator-based impactor was developed - the MEMS Impactor Stage (MIS) - capable of accommodating various nozzle and resonator combinations. Square lateral bulk acoustic resonators were the primary topology, but the results within the thesis are widely applicable. A series of laboratory studies covered the resonator lifetime, reusability, detection limits, and response to environmental changes. The resonator displayed a high sensitivity throughout, capable of detecting ultrafine particles, but is vulnerable to misinterpretation. Beyond mass measurement, studies introduced possible extensions to hygroscopicity and compositional applications. Ambient particle measurements with the MIS, simulating a real-world application to air quality monitoring, showed the capabilities as a PM instrument while highlighting concerns to be addressed for future instrument design. A microresonator-based impactor has potential as an alternative to OPCs, but its cross sensitivity to deposition patterns and environmental effects must be accounted for prior to implementation as PM monitor.

The overall goal of this doctoral dissertation is to develop a prototype instrument, a Portable Aerosol Collector and Spectrometer (PACS), that can continuously measure aerosol size distributions by number, surface area and mass concentrations over a wide size range (from 10 nm to 10 µm) while also collecting particles with impactor and diffusion stages for post-sampling chemical analyses. To achieve the goal, in the first study, we designed, built and tested the PACS hardware. The PACS consists of a six-stage particle size selector, a valve system, a water condensation particle counter to measure number concentrations and a photometer to measure mass concentrations. The valve system diverts airflow to pass sequentially through upstream stages of the selector to the detectors. The stages of the selector include three impactor and two diffusion stages, which resolve particles by size and collect particles for chemical analysis. Particle penetration by size was measured through each stage to determine actual performance and account for particle losses. The measured d50 of each stage (aerodynamic diameter for impactor stages and geometric diameter for diffusion stages) was similar to the design. The pressure drop of each stage was sufficiently low to permit its operation with portable air pumps. In the second study, we developed a multi-modal log-normal (MMLN) fitting algorithm to leverage the multi-metric, low-resolution data from one sequence of PACS measurements to estimate aerosol size distributions of number, surface area, and mass concentration in near-real-time. The algorithm uses a grid-search process and a constrained linear least-square (CLLS) solver to find a tri-mode (ultrafine, fine, and coarse), log-normal distribution that best fits the input data. We refined the algorithm to obtain accurate and precise size distributions for four aerosols typical of diverse environments: clean background, urban and freeway, coal power plant, and marine surface. Sensitivity studies were conducted to explore the influence of unknown particle density and shape factor on algorithm output. An adaptive process that refined the ranges and step sizes of the grid-search reduced the computation time to fit a single size distribution in near-real-time. Assuming standard density spheres, the aerosol size distributions fit well with the normalized mean bias (NMB) of -4.9% to 3.5%, normalized mean error (NME) of 3.3% to 27.6%, and R2 values of 0.90 to 1.00. The fitted number and mass concentration biases were within ± 10% regardless of uncertainties in density and shape. With this algorithm, the PACS is able to estimate aerosol size distributions by number, surface area, and mass concentrations from 10 nm to 10 µm in near-real-time. In the third study, we developed a new algorithm–the mass distribution by composition and size (MDCS) algorithm–to estimate the mass size distribution of various particle compositions. Then we compared the PACS for measuring multi-mode aerosols to three reference instruments, including a scanning mobility particle sizer (SMPS), an aerodynamic particle sizer (APS) and a nano micro-orifice uniform deposit impactor (nanoMOUDI). We used inductively coupled plasma mass spectrometry to measure the mass of collected particles on PACS and nanoMOUDI stages by element. For the three-mode aerosol, the aerosol size distributions in three metrics measured with the PACS agreed well with those measured with the SMPS/APS: number concentration, bias = 9.4% and R2 = 0.96; surface area, bias = 17.8%, R2 = 0.77; mass, bias = -2.2%, R2 = 0.94. Agreement was considerably poorer for the two-mode aerosol, especially for surface area and mass concentrations. Comparing to the nanoMOUDI, for the three-mode aerosol, the PACS estimated the mass median diameters (MMDs) of the coarse mode well, but overestimated the MMDs for ultrafine and fine modes. The PACS overestimated the mass concentrations of ultrafine and fine mode, but underestimated the coarse mode. This work provides insight into a novel way to simultaneously assess airborne aerosol size, composition, and concentration by number, surface area and mass using cost-effective handheld technologies.

Sampling of airborne dust in industry is influenced by the potential health effects associated with human exposure. Health effects depend on mass concentration and particle size which influences the site of pulmonary deposition. Occupational diseases tend to be associated with dust deposition in specific regions of the respiratory tract. The ACGIH size selective TLVs are expressed in three forms: Inhalable Particulate Matter, Thoracic Particulate Matter, and Respirable Particulate Matter. In pneuomoconioses, the amount of dust deposited in the lungs can be estimated by sampling the respirable fraction. Dose-response relationships are derived by relating the health experience of workers to the extent of their exposure to respirable dust. It can be readily seen that validity of these relationships depends primarily on the accuracy of estimation of the exposure dose. Different sampling techniques, such as impactors, horizontal elutriators and cyclones were used for decades to estimate the exposure to respirable dusts. Cyclones have been the most widely utilized. However, the performance curve of the cyclone is considerably different from observed dust deposition data in the human alveolar compartment. Current methods of measuring respirable dust overestimate that dust fraction, which results in underestimating the agent’s toxicity in dose-response relationships. In this investigation, a new concept for sampling respirable dust was proposed and validated. The goal of this study was to design a combined impactor/cyclone device that provides better estimation of the amount of respirable dust. The objectives of this study were: 1) to calibrate ten single-stage impactors previously deigned and machined by Dr. Hammad, 2) to obtain the collection efficiency curves of ten impactor-cyclone combinations by superimposing the collection efficiency curves of impactors on the well-defined cyclone efficiency curve, and 3) to compare the combined efficiency curves to actual human alveolar deposition data, and thus validate this new concept for sampling of respirable dust. The experiment was conducted in a 20’’x20’’x20’’ aerosol testing chamber constructed from aluminum with a glass window. A LoveLace nebulizer with a nominal droplet size of 7 micrometers was used to generate fluorescent monodisperse polystyrene latex aerosols 0.5, 1, 2, and 3 micrometers in diameter. A Vilnius aerosol generator was used to generate fluorescent PSL dry powders 6 micrometers in diameter. The generated aerosols were collected on 37 mm polyvinyl chloride filters positioned after the impactors. Sample fluorescence was determined using a GloMax-Multi Jr fluorometer. Impactor efficiencies at the various sizes were used to construct the collection curves of impactors. Efficiency curves were subsequently superimposed on the cyclone efficiency curve to obtain the final efficiencies of the sampling devices. The results indicated that the cut-off diameters increased with impactor jet size. The new efficiency curves of the sampling devices had similar shapes to actual alveolar deposition as determined experimentally in human subjects. Actually they fell between actual alveolar deposition curves 2 and 4 seconds for mean residence times. The findings from this work can be applied to design a novel respirable dust sampler that provides a realistic estimate of pulmonary deposition to be used in dose- response relationships for the various mineral dusts encountered in general and mining industries. The under estimation of the dust toxicity associated with the current sampling methodology may be one of the reasons for continuous lowering of the TLV and PEL for silica.

[pt] O impactador inercial em cascata é um instrumento no qual uma amostra de ar e poluentes (aerossóis) é obrigada a percorrer um trecho contendo obstáculos, chamados placas de impactação. Os obstáculos forçam o jato a mudar de direção, mas como as partículas têm maior inércia do que o fluido, não acompanham as linhas de corrente do escoamento e acabam por depositar-se sobre estes obstáculos. Diferenças na geometria envolvendo diminuição de área de passagem de escoamento e conseqüente aumento de velocidades, fazem com que, a cada estágio, partículas de diâmetros menores sejam coletadas. O desafio é projetar um instrumento que maximize a eficiência de coleta, diminuindo as perdas por deposição indesejável de partículas nas paredes, recirculações e outros efeitos. Nesta Dissertação de Mestrado foi realizado o projeto de um impactador de três estágios coletando, respectivamente, partículas com diâmetro aerodinâmico de 10, 2,5 e 1 (mi)m, operando com vazão de 30 lpm (litros por minuto) e pressão atmosférica. Na análise de desempenho do instrumento, foram realizadas simulações numéricas com o objetivo de analisar características do escoamento e da trajetória de partículas e levantar as curvas de eficiência de coleta. Foram realizados, também, testes experimentais reproduzindo condições de uso com o intuito de levantar as curvas de eficiência reais. Os resultados numéricos e experimentais foram comparados e apresentam-se ao final, conclusões sobre o desempenho do instrumento e recomendações para trabalhos futuros. / [en] Impactors are simple devices in which a sample flows of air and pollutants flow around an obstacle, called impaction plate. Particles with sufficient inertia will slip across the flow streamlines and impact on the obstacle. Particles with less inertia will follow the airflow away from the impaction surface. Inertial cascade impactors have more than one impaction area. Each one has an impaction plate and a nozzle plate. From one stage to the other, the nozzle diameters become smaller and, consequently, the velocities are higher. This allows for the collection of smaller particles. The challenge is to design an instrument with the higher collection efficiency as possible, reducing wall losses, recirculation regions and other effects. In this study a 3-stages inertial cascade impactor was designed and tested. The cut-point aerodynamic diameters for each stage were 10, 2.5 and 1 (mi)m, respectively, when operating with a flow rate of 30 l/min at atmospheric pressure. To evaluate the instrument, some numerical simulations were performed. They provided results for the flow field, particle trajectories and the collection efficiency curves. Experimental tests were also done to allow for the determination of the real efficiency curves. The numerical and experimental data were compared. Finally, the conclusions of the work and recommendations for future studies are presented.

PhD / Electrostatics of aerosols for inhalation is a relatively new research area. Charge properties of these particles are largely unknown but electrostatic forces have been proposed to potentially influence lung deposition. Investigation on the relationship between formulation and aerosol charging is required to understand the fundamental mechanisms. A modified electrical low pressure impactor was employed to measure the particles generated from metered dose inhalers and dry powder inhalers. This equipment provides detailed size and charge information of the aerosols. The particles were sized by impaction onto thirteen stages. The net charges in twelve of the size fractions were detected and recorded by sensitive electrometers. The drug deposits were quantified by chemical assay. The aerosol charge profiles of commercial metered dose inhalers were product-dependent, which was due to differences in the drug, formulation, and valve stem material. The calculated number of elementary charges per drug particle of size ≤ 6.06 μm ranged from zero to several ten thousands. The high charge levels on particles may have a potential effect on the deposition of the aerosol particles in the lung when inhaled. New plastic spacers marketed for use with metered dose inhalers were found to possess high surface charges on the internal walls, which was successfully removed by detergent-coating. Detergent-coated spacer had higher drug output than the new ones due to the reduced electrostatic particle deposition inside the spacer. Particles delivered from spacers carried lower inherent charges than those directly from metered dose inhalers. Those with higher charges might be susceptible to electrostatic forces inside the spacers and were thus retained. The electrostatic low pressure impactor was further modified to disperse two commercial Tubuhaler® products at 60 L/min. The DPIs showed drug-specific responses to particle charging at different RHs. The difference in hygroscopicity of the drugs may play a major role. A dual mechanistic charging model was proposed to explain the charging behaviours. The charge levels on drug particles delivered from these inhalers were sufficiently high to potentially affect deposition in the airways when inhaled. Drug-free metered dose inhalers containing HFA-134a and 227 produced highly variable charge profiles but on average the puffs were negatively charged, which was thought to be due to the electronegative fluorine atoms in the HFA molecules. The charges of both HFAs shifted towards neutrality or positive polarity with increasing water content. The spiked water might have increased the electrical conductivity and/or decreased the electronegativity of the bulk propellant solution. The number of elementary charges per droplet decreased with decreasing droplet size. This trend was probably due to the redistribution of charges amongst small droplets following electrostatic fission of a bigger droplet when the Raleigh limit was reached.

To characterize the size distributions, concentrations and sources of heavy metal associated with suspended particles, a total of 12 months of sampling periods were taken by Micro-Orifice Uniform Deposit Impactor (MOUDI) in the Nantzu Export Processing Zone from January to December 2011, The concentrations of suspended particles ranged from 54.7 to 203 £gg/m3. Both autumn and winter had significantly higher levels of suspended particles than in spring and summer. The mass concentrations of fine particles accounted for ~50% of the mass concentrations of suspended particles. The mass concentrations of PM2.5 accounted for 50.2-70% of the mass concentrations of PM10. The mass concentrations of PM1 accounted for 24-38.3% of the mass concentrations of PM10. These results indicated that fine particles dominated in atmospheric particulates in Nanzih Export Processing Zone. In addition, among the PM10, PM2.5 and PM1, significant correlations were found. The crustal elements (Al, Fe, Ca, Mg, K and Na) and sulfate are dominant during the sampling periods, which accounting for ~95% of the total concentrations. The crustal elements were observed mainly in coarse particles, while sulfate was found mainly in fine particles. The concentrations of all crustal elements decreased in summer could be attributed to the meteorological conditions and chemical mechanism. By using the enrichment factor (EF) to distinguish the sources of heavy metals in PM10, PM2.5 and the results showed that EF values of crustal elements in PM10 ranged from 1 to 10, suggesting PM10 might come from the resuspension of soil and road dust. In addition, Pb, Zn, As, Se, Mo, Sb and sulfate were observed at higher EF values in both PM2.5 and PM1, indicating the influence of anthropogenic emissions in fine particles. The results from Pearson¡¦s correlations indicated that PM10 in the Nantzu Processing Zone were mainly from the resuspension of soil and road dust, while fine particles (PM2.5 and PM1) may be from the traffic emissions and petrochemical industry in Nanzih and Renwu.

No description available.

Η χορήγηση φαρμάκων μέσω της αναπνευστικής οδού αποτελεί τον πιο αποτελεσματικό τρόπο αντιμετώπισης νόσων του αναπνευστικού συστήματος όπως το άσθμα. Τα τελευταία χρόνια, η αύξηση στη συχνότητα εμφάνισης του άσθματος δημιούργησε την ανάγκη βελτίωσης της θεραπείας με το σχεδιασμό νέων συσκευών εισπνοής και την ανάπτυξη καλύτερης μορφοποίησης των φαρμάκων ώστε να εξασφαλίζεται ικανοποιητική κατανομή τους στο αναπνευστικό δένδρο. Στην παρούσα μελέτη, λαμβάνοντας υπόψη τις δυσκολίες ανάπτυξης ενός φαρμάκου για εισπνεόμενη χορήγηση, αποφασίσαμε να ασχοληθούμε με τη μορφοποίηση της φουμαρικής φορμοτερόλης, ενός ευρέως χρησιμοποιούμενου βρογχοδιασταλτικού φαρμάκου στη θεραπεία του βρογχικού άσθματος. Στόχος είναι η ανάπτυξη της βέλτιστης μορφοποίησης με την οποία θα επιτυγχάνεται το μέγιστο θεραπευτικό κλάσμα FPD. Διερευνήθηκε η επίδραση διαφόρων παραγόντων στη μεταφορά και εναπόθεση των λεπτόκοκκων σωματιδίων της φουμαρικής φορμοτερόλης στο αναπνευστικό δένδρο. Συγκεκριμένα, μελετήθηκε η επίδραση της κατανομής μεγέθους των σωματιδίων της λακτόζης στη μορφοποίηση και προσδιορίστηκε η κατανομή που επιτρέπει ικανοποιητική προσκόλληση της φουμαρικής φορμοτερόλης στη λακτόζη αλλά και εύκολο διαχωρισμό της απ’ αυτήν κατά την εισπνοή. Στη συνέχεια, διεξήχθησαν πειράματα προσδιορισμού του ιδανικού χρόνου ανάμιξης και των συνθηκών παραγωγής που εξασφαλίζουν ικανοποιητική ροή των κόνεων και πλήρωση των κυαθίων και δεν επηρεάζουν τη χημική σταθερότητα του φαρμάκου. Ακολούθησαν πειράματα για την αξιολόγηση της επίδρασης της μεταβολής στο βάρος πλήρωσης του κυαθίου στη μορφοποίηση και κατ’ επέκταση στο θεραπευτικό κλάσμα FPD. Τέλος, η μελέτη ολοκληρώθηκε μ’ ένα πείραμα ελέγχου της επίδρασης των εργαστηριακών συνθηκών στο Andersen Cascade Impactor και συνεπώς στη σταθερότητα του προϊόντος αλλά και την ικανότητα διασποράς του. / Drug delivery through the respiratory tract constitutes the most effective way of treating respiratory diseases such as asthma. Over the last years, the increased frequency of asthma occurrence challenged the improvement of therapy with the design of new inhalers and a better formulation development of drugs so as to achieve effective drug distribution to the respiratory tree. In the current study, having taken into consideration the difficulties of drug development for inhalation delivery, we have decided to work on the formulation of formoterol fumarate, a bronchodilator broadly used to the treatment of bronchial asthma. The aim is the optimization of formulation development so as to achieve the optimum therapeutic fraction FPD. The main idea was the examination of the effect of certain parameters on the delivery and deposition of formoterol fumarate fine particles to the respiratory tree. Specifically, the effect of lactose size distribution on the formulation was studied and the size distribution that allows not only effective adherence of formoterol fumarate to lactose but also efficient release during inhalation was determined. As a next step, experiments were carried out for the determination of the ideal mixing time and manufacturing conditions for satisfactory powder flowability, blister filling and chemical stability of drug. Experiments for the evaluation of the effect of blister filling variation on the formulation and consequently on the therapeutic fraction FPD followed. Finally, this study was completed by controlling the effect of laboratory conditions on the Andersen Cascade Impactor and consequently on the product stability and its dispersion ability.