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Étude de la réactivité du chlore atomique avec des particules d’aérosol d’intérêt atmosphérique / The heterogeneous reactivity of atomic chlorine with aerosol particles of atmospheric interestCiuraru, Raluca 15 December 2010 (has links)
L’atmosphère est un milieu oxydant au sein duquel les réactions en phase homogène, initiées par des espèces radicalaires (OH notamment), sont prépondérantes. Le chlore atomique peut être l'oxydant le plus important de la couche limite marine à l'aube lorsque la concentration en radicaux OH est faible. L’atmosphère est aussi chargée en particules d’aérosol où des collisions réactives peuvent se produire à l’interface gaz/solide ou gaz/liquide. Il est donc important de prendre en compte les mécanismes élémentaires de chimie hétérogène pour une meilleure description des processus physico-chimiques atmosphériques. L’objectif de cette thèse est d’étudier la réactivité entre le chlore atomique et des particules représentatives des sels marins (NaCl et sels marins synthétiques). Des mesures ont également été effectuées avec du sulfate et du nitrate d’ammonium, composés majoritaires dans les particules secondaires issues de la condensation d’espèces gazeuses d’origine anthropique. Le principe consiste à mettre une phase gazeuse en contact avec une phase solide au sein d’un réacteur à écoulement à parois recouvertes couplé à un spectromètre de masse. Nous cherchons à mesurer la vitesse de réaction et à déterminer le coefficient de capture de ces réactions ainsi que les produits formés. Nous avons fait varier un certain nombre de paramètres : concentration des réactifs, température, présence ou non de vapeurs d’eau. L’analyse de la surface solide après réaction a été réalisée par des techniques de microscopie avancée (XPS, TOF SIMS). / The atmosphere is an oxidizing environment in which the homogeneous phase reactions initiated by radical species (OH in particular) are dominant. Atomic chlorine could be the most important oxidant in the marine boundary layer at dawn when the concentration of OH radicals is low. The atmosphere is loaded with aerosol particles, on the surface of which reactive collisions can occur at the gas / solid or gas / liquid interfaces. It is therefore important to take into account the basic mechanisms of heterogeneous chemistry for a better description of atmospheric chemical and physical processes. The objective of this thesis is to study the reactivity between chlorine atoms and particles representative of sea salts (NaCl and synthetic sea salts). Measurements have also been carried out with ammonium sulfate and nitrate particles, the major components in the secondary particles formed by the condensation of gaseous species of anthropogenic origin. The principle is to put a gas phase in contact with a solid surface in a coated wall flow tube reactor and microwave discharge coupled to a quadrupole mass spectrometer. The contact time between the two phases can be varied inside the reactor. In this work, we have measured the reaction rate and determined the uptake coefficient of these reactions and the possible products formed. Several parameters have been studied: the concentration, the temperature and the presence or absence of surface adsorbed water. The solid surface was analyzed after reaction by advanced microscopy techniques (XPS, TOF SIMS) during this study.
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Effects of humidity and fatty acid surfactants on the uptake of NO2 to NaCl : combined study of kinetics and surface analysis / Effet de l'humidité et de molécules tensio-actives sur la capture du dioxyde d'azote (NO2) par le chlorure de sodium (NaCl) : etude cinétique et analyse de surfaceScolaro, Sara 05 November 2009 (has links)
Des études cinétiques et des analyses de surface ont été effectuées sur la réaction multiphasique entre le gaz NO2 et des cristaux de NaCl en présence de molécules tensio-actives sous air humide. Ces études de laboratoire contribuent à la validation de processus de chimie atmosphérique suggérés par des campagnes de mesure sur des aérosols d’origine marine. Les vents provoquant des vagues à la surface des océans propulsent de nombreuses gouttelettes d’eau de mer dans la troposphère où elles se déshydratent partiellement et forment l’aérosol marin, constitué de particules de taille micrométrique comportant du NaCl et de nombreux composés mineurs dont des acides gras (stéarique, oléique). Les concentrations en particules peuvent dépasser 20 µg/m3 dans l’air des zones côtières. Des quantités énormes d’oxydes d’azote (NO, NO2) sont émises actuellement par les transports et le chauffage et leur concentrations peuvent dépasser 100 µg/m3 dans les zones fortement antropisées. Le passage de masses d’air d’origine marine dans des zones fortement urbanisées a des impacts négatifs sur la qualité des eaux continentales par des pluies chargées en nitrates et sur la qualité de l’air par des dégagements de gaz chlorés. La cinétique de la réaction montre que la capture de NO2 par NaCl est favorisée a des fortes humidités. Par contre un revêtement d’acides gras réduit peu la production de NaNO3 et l’émission de NOCl. Les études de surfaces par microimagerie Raman polarisée et microscopie à force atomique mettent en évidence des processus de précipitation et de migration de surface dans la production de nanocristaux de NaNO3 et le faible rôle protecteur des molécules tensio-actives. / In this laboratory work we studied an important atmospheric process typical of polluted costal regions: the heterogeneous reaction of a gaseous pollutant of mainly anthropogenic origin, NO2, on NaCl(100), taken as a surrogate for marine aerosol. Evidence of the presence of a native organic coating on field-collected marine aerosol particles inspired us to investigate the effect of insoluble fatty acids on the heterogeneous removal reaction of NOx in the marine boundary layer. The originality of this work consists in coupling reactivity studies with high spatial resolution surface analysis. The surface is followed, before and after reaction, via Raman micro-spectrometry and AFM techniques. Significant modifications in the morphology and orientation of the formed NaNO3 crystals on the surface are found as a function of humidity during the reaction. A thin organic coating on the salt surface is prepared and characterized. The reactivity of the coated/uncoated salt is measured in a static reactor where the gaseous phase composition can be monitored by FTIR spectrometry in different humidities (RH=0-80%). From NO2 and ClNO kinetics we can independently estimate both the uptake and the reaction probability coefficients. The presence of a palmitic or oleic acid coating slightly hinders the reactivity, especially in some humidities. By coupling all experimental information to a simple reactivity model which fits the experimental data well, we can conclude that the NO2/NaCl reaction directly releases a precursor of active chlorine atoms (ClNO) into the atmosphere, even at high humidities.
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Post-Synthesis Functionalization of Porous Organic Polymers for CO2 CaptureAl Otaibi, Mona S. 07 1900 (has links)
Solid porous materials are network materials that contain space void. Porous Organic Polymers (POPs) are porous materials, which are constructed from organic building blocks and exhibit large surface area with low densities. Due to these characteristics, POPs have attracted attentions because of their potential use in application such as gas storage and chemical separation.
This thesis presents a study of the synthesis of novel POP being a network based on 2,5- dibromobenzaldehyde and 1,3,5-triethynylbenzene linked together via Sonogashira- Hagihara (SH) coupling. This network showed a relatively good surface area of 770 m2/g and total pore volume of 0.59 cc/g. In addition, it proved to be chemically and thermally stable, maintaining the thermal stability up to 350oC.
In addition to synthesize novel aldehyde-POP network, it was also possible to post synthetically modify a network via one-step post synthetic functionalization by amine. Ethelynediamine (EDA), Diethylenetriamine (DETA), and Tris(2-aminoethyl)amine (Tris-amine) are three different amines used for aldehyde-POP functionalization. The produced networks were aminated via different amine species substitution the aldehyde group present within the network. Modification to these networks resulted in a decrease in surface area from 770 m2.g-1 to 333 m2.g-1, 162 m2.g-1, and 211 m2.g-1 in respective to EDA, DETA, and Tris-amine. Although the surface areas were decreased, the CO2 adsorption was enhanced as evidenced by the increase of Qst (i.e., from 25 to 45 kJ.mol-1 for DETA at low coverage).
Our findings are expected to strengthen existing research areas of the influence of different type of amines (e.g aromatic amine) on CO2 adsorption. Although amine grafting has been studied in other systems (e.g., PAFs and MOFs), we are the first to reported amine functionalized POPs using a novel one-step amine grafting PSM procedure. Future research might extend to study the interaction between CO2 and amine species under real working conditions.
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Synthesis and Study of Modified-Nanocrystalline Cellulose Effective for SO2 CaptureZafari, Raheleh 20 December 2021 (has links)
One of today’s world's main challenges is access to a clean environment. The release of hazardous and toxic gases from burning fossil fuels is of critical concern due to these gases' destructive effects on the nearby atmosphere. Among these, acid rain is one of the most severe consequences of air pollution caused by sulfur dioxide (SO2) gas and still needs to be better addressed. One of the solutions is the adsorption-based technologies because of their ease of use, possible high adsorption capacity, minimum environmental impact, low cost, and efficient sorbate recovery possibilities. Gas separation via adsorption is not yet widely employed commercially since it needs regenerable, high-durable, high-performance, and cost-effective adsorbents. One of the common methods of absorbing acid gases is the use of amino absorbents that have disadvantages such as create many waste materials challenging to regenerate, wastewater, and waste gas. Therefore, incorporating amine groups on the surface of solids to overcome the problem of regeneration has attracted considerable attention in gas uptake.
In this project, we proposed to functionalize nanocrystalline cellulose (NCC) using a solvent-free method to boost their SO2 interactions and thus their adsorption capability. Therefore, a commercial NCC material was modified using ethylenediamine (EDA) in green and straightforward amination approach in order to tune its surface basicity and obtain an efficient green-biobased adsorbent. Since the substitution process of amines with hydroxyl groups on the cellulose surface is carried out through dangerous halogen solvents, we used the solvent-free one-step method and investigated the synthetic parameters.
Amination conditions of NCC adsorbents were optimized via the effects of the amination temperature, the amination time, and the amount of EDA on their physical properties and their performance for SO2 adsorption. The sorbents were characterized using attenuated total reflection-Fourier-transform infrared spectroscopy (ATR-FTIR), solid carbon nuclear magnetic resonance (13CNMR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy- energy-dispersive X-ray spectroscopy (SEM-EDS) to see if EDA was incorporated into the NCC and investigate the changes in thermal stability of adsorbents by changing synthesis conditions. Sorbents were then tested for SO2 capture at the same conditions of room temperature (RT), atmospheric pressure, and a flow rate of 20 ml/min, which was selected based on previous studies to optimize flow rate in the same research group. The optimal conditions to create an effective sulfur dioxide adsorbent were found to be 70 oC for 8 hours of amination. At ideal conditions, the NCC modified had an SO2 adsorption capacity value of 0.030 mg/100 mg. The promising properties of EDA-NCC in terms of adsorption capacity (showing a significant increase in capacity when compared to the NCC at atmospheric pressure and ambient temperature) make them potential adsorbent candidates.
In addition, the impacts of SO2 capture operating conditions on adsorption capacity were evaluated. By varying the adsorption temperature from room temperature to 60 °C and the feed flow rate from 10 to 30 ml min-1, fixed-bed breakthrough studies for SO2 adsorption onto NCC and modified-NCC adsorbent (prepared at 70oC, 3hr, and EDA/NCC=25) were carried out. Over the range of operating parameters studied, the greatest SO2 capacity and breakthrough time values were obtained with adsorbent at room temperature and 20 ml min-1 input flow rate. As expected, due to the exothermic nature of the adsorption process, the amount of SO2 adsorbed at equilibrium decreased with increasing temperature. It was also observed that as the flow rate increases, the breakthrough time decreases due to the higher flow rate of the feed gas was accompanied by the faster transport of the adsorbate molecules and leading to a shorter breakthrough time, as expected.
Finally, another EDA functionalization method was tested, using a two-step method. First, cellulose was functionalized using citric acid (CA), and then the EDA was incorporated via carboxylic acid functional groups in the CA to obtain both amide and amine groups on the NCC’s surface. This approach aimed to compare EDA deposition on cellulose surface via a different method by adding one more functional group and evaluating their performance in SO2 gas adsorption. It was concluded that oxygenated functional groups and groups with low alkalinities, such as carboxylic acid and amide, can negatively affect gas adsorption. These results were concluded by comparing two adsorbents, one containing only amine groups and the other adsorbent containing amide and carboxylic acid groups in addition to the amine group, although the amine content of the two adsorbents was different. Future research will explore the mechanisms and capturing phenomena to improve capturing capacity and process applicability as well as the material optimal regeneration operating conditions.
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Sensor Based Motion Tracking and Recognition in Martial Arts Training / Sensor Based Motion Tracking and Recognition in Martial Arts TrainingAgojo, Stephan January 2017 (has links)
In various martial arts, competitors are interested in quantifying and categorising techniques which are exercised during training. The implementation of embedded systems into training gear, especially a portable wireless body worn system, based on inertial sensors, facilitates the quantification and categorisation of forces and accelerations involved during the training of martial arts. The scope of this paper is to give a brief overview of contemporary technology and devices, describe key methods that are implemented in such devices and as well to provide a project outline. For this reason a literature research was carried out using search engines and databases. The search yielded that devices are capable of tracking activities of daily life; however only one product was found which can track and recognise techniques applied in martial arts training just for the upper body. The realisation of a sensor based tracking system which can track and classify different exercises is possible with present technology. Even so, different challenges such as implementing a sensor fusion and classifier algorithm need to be overcome. Therefore, the project development has to be viewed as an iterative process.
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Piano-related Musculoskeletal Disorders: Posture and PainShamoto, Yoshiko 05 1900 (has links)
A healthy posture protects the body-supporting functions and prevents injuries by maintaining balance. Literature in performing arts medicine suggests that posture is an important component to prevent piano-playing related injuries. However, no known research studies have quantified, characterized, and compared pianists' sitting postures. The purpose of this study was to explore the relationship between playing postures and perceived pain among pianists. This study applied innovative approach using qualitative and quantitative methods, combined with three-dimensional motion captured technology. To examine risk factors related pianists' postures, three-dimensional motion-capture cameras recorded approximate 40 pianists' postures in various situations; data recordings were combined with a statistical method to investigate pain-posture correlations. Results reveal that the degrees of head-neck or body tilt angles are the tendency of risk factors for piano-playing related pain. Results from this study may have multiple practical implications among which are: (1) a risk factor pain, injury index, or indicator (2) a performance habits profile and (3) practice guide to prevention of piano-playing related musculoskeletal disorders.
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Selected impacts of missing data problem in economicsUenal, Hatice January 2018 (has links)
Data sources and data quality are indispensable in economical, medical, pharmaceutical or other studies and provide the basis for reliable study results in numerous research questions. Depending on the purpose of use, a high quality of data is a prerequisite. However, with increasing registry quality, costs also increase accordingly. Considering these time and cost consuming factors, this work is an attempt to estimate the cost advantages when applying statistical tools to existing registry data. This includes methodological considerations and suggestions regarding the evaluation of data quality including factors such as bias and reliability after dealing properly (or not) with missing data (MD), and possible consequences when ignoring the incompleteness of data. Results for the quality analysis of the gastric cancer patients’ data example showed that millions of Euros in study costs can be saved by reducing the time horizon. On average, €523,126.70 can be saved for every year that the study duration is shortened. Replacing additionally the over 25% of MD in some variables, data quality was immensely improved, but still showed quality difficulties, which – beside MD in variables – could be an indication for completely missing entries of patients in the registry. Capturerecapture methods were therefore discussed to demonstrate how the total completeness in a registry can be estimated. Since it was not possible to illustrate the CARE method with the example of the gastric cancer patients due to the given data structure (no access to required variables), other data sets had to be chosen – the publicly accessible data of the amyotrophic lateral sclerosis (ALS) and data of towed vehicles in the City of Chicago. The consequence of ignoring MD was further analyzed using bankruptcy prediction data sets of agribusiness companies and confirmed the assumption that MD have a negative impact on the data quality, in this case also regarding the misclassifications of predictions of bankrupted companies. Using the decision tree method (known as one of the most suitable methods in predicting financial distress), the percentage of correctly bankruptcy-predicted of bankrupted companies (one year to bankruptcy) with MD imputation was 87.5%, whereas it was only 60% when completely omitting MD. Overall, my findings showed dearly the importance of statistical methods to improve data quality which in turn helps to avoid drawing biased conclusions due to incomplete data.
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Möjligheter till fastighets- och exploateringsrelaterad värdeåterföring i transportinfrastrukturprojekt : En jämförelse av svenska förhållanden med London och Hong Kong / Possibilites for property related value capture in transport infrastructure projects : Swedish institutional arrangements in comparison to London and Hong KongWitzell, Jacob January 2013 (has links)
Offentliga investeringar i transportinfrastruktur genererar ofta ökade markvärden. Detta värdesamband kan nyttjas som finansieringskälla för infrastrukturinvesteringar genom att delar av det ökade markvärdet inhämtas till det offentliga genom så kallad värdeåterföring. Möjligheterna till värdeåterföring avgörs av faktorer såsom rådande markägoförhållanden, ansvarsfördelning för planering och genomförande av transportinfrastruktur respektive bebyggelseutveckling liksom utformning av lagstiftning, skatte- och avgiftsinstrument. I detta arbete undersöks möjligheterna till fastighets- och exploateringsrelaterad värdeåterföring i Sverige. Arbetet innehåller en genomgång av relevanta institutionella förhållanden liksom tillgängliga värdeåterföringsmetoder. En fallstudie kring finansieringen av en pendeltågsstation och trafikplats i Vegastaden, Haninge, exemplifierar hur värdeåterföring kan tillämpas under rådande institutionella förhållanden. Fallstudier kring värdeåterföring i London och Hong Kong visar på hur värdeåterföring kan tillämpas under andra institutionella förhållanden. De institutionella förhållandena i Sverige jämförs med London och Hong Kong med hjälp av teorier kring markvärden, klubbar, transaktionskostnader och förhandlingar. En referensmodell kring graden av fragmentisering respektive samlat ansvar i planering respektive genomförande av transportinfrastruktur och bebyggelse tillämpas i syfte att tydliggöra skillnader i institutionella förhållanden. I Sverige är möjligheterna till värdeåterföring starkt knutna till kommunens så kallade planmonopol och därtill hörande värdeåterföringsinstrument. Stat och region/landsting är i hög grad hänvisade till frivilliga avtal respektive offentligt markägande för att direkt kunna tillgodogöra sig värdeåterföring. Planering och genomförande av bebyggelse och transportinfrastruktur är samtidigt fragmenterad i Sverige, med ett flertal offentliga och privata aktörer inblandade. Samverkan och förhandlingsöverenskommelser blir viktiga inslag i planering, finansiering och genomförande. Värdeåterföring i den svenska fallstudien sker genom ad-hoc-artade förhandlingsprocesser. I London ger institutionella förhållanden regionen en starkare roll i planeringen av transportinfrastruktur och bebyggelse än i Sverige, liksom tillgång till särskilda värdeåterföringsinstrument. Planeringen är mindre fragmenterad, men i genomförandet liknar förhållandena de svenska. Värdeåterföring kan ske i mer samlad form genom regionalt samordnade avgifter och skatteuttag. I Hong Kong genomförs samordnade infrastruktur- och bebyggelseprojekt av en samlad aktör med ett brett mandat. Värdeåterföring tillämpas genom internalisering av uppkomna värden till följd av offentligt markinnehav och egen fastighetsutveckling. I Hong Kong tillämpas därmed såväl samlad planering som ett samlat genomförande av transportinfrastruktur och bebyggelse, utifrån institutionella förhållanden som skiljer sig kraftigt från de svenska. Institutionella förändringar i Sverige som skulle kunna minska fragmentiseringen i planeringsfasen skulle kunna vara en stärkt regional planering liksom regionala värdeåterföringsinstrument enligt London-modellen. För att närma sig förhållandena i Hong Kong skulle det krävas betydligt mer långtgående förändringar av institutionella förhållanden rörande planering och genomförande, vilka i grunden skulle kräva starka inskränkningar i den privata äganderätten till mark. / Public investment in transport infrastructure often generates increased land values. This value can be used as a funding source for infrastructure investments by applying methods for value capture. The possibilities for value capture is determined by factors such as land ownership patterns, the organisation of planning and implementation of transport infrastructure and land development, as well as the design of legislation, taxes and charging instruments. This essay explores the possibilities for property relatated value capture in Sweden. The essay includes an overview of relevant institutional arrangements as well as available value capture methods. A case study on the financing of a commuter rail station and traffic junction in Vegastaden, Haninge, exemplifies how value capture can be applied under current institutional arrangements. Case studies on value capture methods in London and Hong Kong show how value feedback can be applied under different institutional arrangements. The institutional conditions in Sweden are compared with those in London and Hong Kong based on theories of land value, club theory, transaction costs and negotiations. A reference model on the degree of fragmentation and assembled responsibility in planning and implementation of transport infrastructure and real estate development is applied in order to clarify the differences in institutional arrangements. In Sweden, the opportunities for value capture are strongly concentrated to the municipality, according to the strong Swedish so called "municipal planning monopoly". The state and regional levels are largely dependent on voluntary agreements or public land ownership to directly benefit from value capture. Further, planning and implementation of real estate development and transport infrastructure is fragmented in Sweden, with a number of involved public and private actors. Collaboration and negotiation are therefore important elements in planning, financing and implementation. Value capture in the Swedish case study is based on ad-hoc-characterized negotiations. In London, institutional arrangements provide the region with a stronger position in the planning of transport infrastructure and real estate development compared to Sweden, as well as access to direct value capture instruments. Planning is less fragmented, but the conditions of implementation are similar to those in Sweden. Value capture by regionally coordinated fees and taxes is possible. In Hong Kong, infrastructure and building projects are often planned and implemented by a single actor based on a broad public mandate. Value capture is practiced by internalization of the generated values as a result of public land holdings and real estate development. The underlying institutional conditions differ significantly from those in Sweden. Institutional changes in Sweden that would reduce fragmentation in the planning phase could consist of a stronger regional planning mandate combined with regional value capture instruments inspired by the London model. In order to approach the situation in Hong Kong, considerably more far-reaching changes to institutional arrangements of planning and implementation would be required, such as strong restrictions on private ownership of land.
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Modelling Soft-Tissue Motion During Human Movement Experiments to Improve Calculations of Skeletal KinematicsBaklouti, Firas 26 May 2021 (has links)
In Canada, approximately 544,000 upper-limb injuries occurred in a 12-month period between 2009 and 2010, many of which were injuries to the rotator cuff muscles of the shoulder. Because of the complex structure and function of the shoulder, it is often difficult to determine which muscles have been injured. The most widely used technology to study human movement is motion capture, wherein markers are affixed to a subject’s skin and are tracked by cameras as the subject moves. The recorded marker trajectories are then used to estimate the bone locations and joint angles during the tracked motion. This is called an inverse kinematic simulation. The simulation can then be used to estimate variables that are difficult or impossible to measure directly, such as the activation of single muscle heads within a muscle group. However, muscles bulge and skin stretches during movement, so the markers that are affixed to the skin generally move relative to the underlying bones. These errors, known as soft-tissue artifacts, lead to uncertainty in the calculation of bone locations and, consequently, uncertainty in the computed skeletal joint angles. This uncertainty limits the use of inverse kinematic simulations in clinical settings. Given the skin tissue’s elastic behaviour, a spring-based equilibrium model can be used to estimate the behaviour of skin during non-impulsive motion. In the proposed model, markers were placed on the surface of ellipsoids (representing the thorax, abdomen, scapula, and upper arm) and were attached to each other via springs. The system was assumed to remain in static equilibrium during sufficiently slow movements to approximate the stretch of the skin. In this thesis, the development and application of a proof-of-concept model to estimate the pose of the skeleton is described. This work demonstrates the feasibility of using such a model to reduce errors due to soft-tissue motion.
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A Motion Capture Based Analysis of the Effects of Body Armor on Shooting PostureBlackledge, Christopher 09 December 2011 (has links)
Body armor designs that limit the range-of-motion required for vital law enforcement tasks, such as shooting may be dangerous. Therefore, a posture based biomechanical analysis was performed to determine if upper body joint angles can be used to assess the effects of armor designs on assumed shooting. Participants (n=8) completed a battery of simulated duty tasks for three armor configurations (no armor, concealable, and tactical armor) while motion capture was used to compute included joint angles of the upper extremity and neck. In general, joint angles were impacted by armor configuration, and law enforcement experience (measured in years) significantly impacted their shooting posture. It was also found that the types of tasks performed interacted with shooting stance. This research is a first step at developing a method to analyze body armor designs and their impact on wearers, so that mobility may not need to be sacrificed for additional protective coverage.
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