Für die Entwicklung von Gesamtfahrzeugeigenschaften ist die objektive Beschreibung von Reifencharakteristika unter der Anwendung entsprechenden Bedingungen von wesentlicher Bedeutung. Der hierzu beschriebene, neuartige Prozess zur Reifencharakterisierung gründet sich auf einem definierten Satz objektiver Gesamtfahrzeugkenngrößen, welche mithilfe dedizierter Fahrmanöver identifiziert werden. Der Kern der hybriden Methode besteht in der zweckmäßigen Klassifizierung von Reifencharakteristika nach Struktur- und Reibgrößen. Auf Basis der kinematischen Deformationsmechanismen in der Reifenkontaktfläche und -konstruktion werden analytische Formulierungen für wesentliche Reifencharakteristika hergeleitet. Die Kombination neuer Prüfmethoden auf Flachbahn- und Anhängerprüfständen erlaubt anschließend deren präzise Identifikation. Zur Zusammenführung der autark gemessenen Eigenschaften wird ein analytisches Synthesemodell beschrieben, welches die Parameteridentifikation von empirischen Reifenmodellen erlaubt. Die Validierung der so identifizierten Reifeneigenschaften erfolgt auf der Gesamtfahrzeugebene. Hier bestätigt sich die maßgebliche Verbesserung der Fahrdynamikrechnung im Linear- und Grenzbereich gegenüber dem bisherigen Stand der Technik.

Le pouce opposable de la main joue un rôle essentiel dans le comportement humain, permettant une prise bien plus précise que celle des singes avec les pouces opposables. Comment le cerveau contrôle t-il les mains aussi précisément? Dans le cadre de cette thèse, nous avons étudié comment différentes régions du cerveau dédiées au contrôle moteur, en particulier le cortex moteur (M1) et l’aire motrice supplémentaire (AMS), contribuent à une pince pouce-index précise. Les résultats de nos études révèlent que des neurones dans l’AMS, en complément de ceux dans M1, communiquent directement avec les motoneurones de la moelle épinière contrôlant les muscles de la main. De plus, SMA communique aussi efficacement que M1 avec les muscles de la main, alors que chez le singe, celle avec M1 est plus efficace. Cette différence fonctionnelle dans la voie AMS-muscles entre le singe et l’Homme pourrait expliquer la plus grande capacité de ce dernier à contrôler finement la force produite par les doigts. / The human hand's opposable thumb plays a large role in human behavior, allowing for a grip far more precise than that of monkeys with opposable thumbs. However, it isn't well understood how the brain controls the hands in such a precise way. In these studies, we investigate how different parts of the brain dedicated to motor tasks, in particular the motor cortex (M1) and the supplementary motor area (SMA), contribute to a precise thumb-index finger grip. Our experiments suggest that some neurons in the SMA, in addition to those well-described in M1, may connect directly to the motoneurons in the spinal cord controlling the hand muscles. Moreover, we found that SMA communicates with the hand muscles as efficiently as M1, while in monkeys, SMA communicates less efficiently than M1. This functional difference in the SMA-muscles pathway between monkey and human may account for the higher capacity of the latter to precisely control the force produced by digits.

The study investigated the impact of computer simulations on the teaching and learning of electromagnetism in grade 11. Electromagnetism is a section of the Physical Science curriculum. Two grade 11 classes in the Mgwenya circuit in Mpumalanga province of South Africa were used as a case study. Using a pre-test, post-test non-equivalent control group design, it was found that learners in the experimental group (n = 30) who were taught using the simulations achieved significantly higher scores on the post-test than learners in the control group (n = 35) who were taught using traditional teacher-centred teaching method; (t statistic = 3.582, df = 56, p<0.05). Learners were more active during the lessons, predicting, observing, discussing and explaining concepts. The use of simulations also provided support (scaffolding) that the learners need to enhance learning. The Hake’s normalized gain for the experimental group <g> = 0.32 compared to <g> = 0.18 for the control group confirmed conceptual improvement. Both teachers and learners indicated that they accept the use of computer simulations in teaching and learning of electromagnetism. / Science and Technology Education / M. Sc. (Mathematics, Science and Technology Education)

Für die Entwicklung von Gesamtfahrzeugeigenschaften ist die objektive Beschreibung von Reifencharakteristika unter der Anwendung entsprechenden Bedingungen von wesentlicher Bedeutung. Der hierzu beschriebene, neuartige Prozess zur Reifencharakterisierung gründet sich auf einem definierten Satz objektiver Gesamtfahrzeugkenngrößen, welche mithilfe dedizierter Fahrmanöver identifiziert werden. Der Kern der hybriden Methode besteht in der zweckmäßigen Klassifizierung von Reifencharakteristika nach Struktur- und Reibgrößen. Auf Basis der kinematischen Deformationsmechanismen in der Reifenkontaktfläche und -konstruktion werden analytische Formulierungen für wesentliche Reifencharakteristika hergeleitet. Die Kombination neuer Prüfmethoden auf Flachbahn- und Anhängerprüfständen erlaubt anschließend deren präzise Identifikation. Zur Zusammenführung der autark gemessenen Eigenschaften wird ein analytisches Synthesemodell beschrieben, welches die Parameteridentifikation von empirischen Reifenmodellen erlaubt. Die Validierung der so identifizierten Reifeneigenschaften erfolgt auf der Gesamtfahrzeugebene. Hier bestätigt sich die maßgebliche Verbesserung der Fahrdynamikrechnung im Linear- und Grenzbereich gegenüber dem bisherigen Stand der Technik.

New technology in radar opens up new possibilities for cheap and easily integrated human body presence detection. In this work, we aim to make a proof of concept that replaces the "dead man’s grip" on an electric surfboard with a more convenient wireless system based on micro radars. To answer the research questions identified, an artifact was created. To guide the research process and ensure that rigorous methods are used for constructing and evaluating the artifact, this thesis employs the research paradigm Design Science Research. The result was that the radar signal is completely degraded without a radome when the radar is wet. With a radome, the signal strength is a third wet compared to dry. Therefore, a radome is required to protect the radar and its function from the elements. The need for blockage detection was also defined. Observing how the direct leakage signal deviates from its normal state can determine whether the sensor is being blocked. Several algorithms were developed and tuned to prove the concept. Coverage and detection speed was tested and optimized. Overall, the potential of micro radars to replace a dead man’s grip on a surfboard is very promising. / Ny radarteknik öppnar nya möjligheter för billig och lättintegrerad upptäckt av människokroppens närvaro. I det här arbetet vill vi göra ett konceptbevis som ersätter "dödmansgreppet" på en elektrisk surfbräda med ett bekvämare trådlöst system baserat på mikroradar. För att besvara de identifierade forskningsfrågorna skapades en artefakt. För att vägleda forskningsprocessen och se till att rigorösa metoder används för att konstruera och utvärdera artefakten används forskningsparadigmet Design Science Research i denna avhandling.  Resultatet var att radarsignalen försämras fullständigt utan radom när radarn är våt. Med en radome är signalstyrkan en tredjedel våt jämfört med torr. Därför krävs en radome för att skydda radarn och dess funktion från väder och vind. Behovet av blockaddetektering definierades också. Genom att observera hur den direkta läckagesignalen avviker från sitt normala tillstånd kan man avgöra om sensorn är blockerad. Flera algoritmer utvecklades och justerades för att bevisa konceptet. Täckning och detektionshastighet testades och optimerades. På det hela taget ser mikroradarns potential att ersätta dödmansgrepp på en surfbräda mycket lovande ut.

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Syfte och frågeställningar Syftet med den här studien har varit att undersöka och jämföra kvinnor och män i åldersgrupperna 30-39 år respektive 40-49 år avseende antropometriska mått samt prestation på GIH:s hälsotester. En vidare målsättning var att undersöka om det förekom några skillnader mellan två separata testtillfällen. Frågeställningarna har varit om resultaten på hälsotesterna skiljer sig mellan könen, åldersgrupperna samt mellan två separata testtillfällen. Metod Totalt fullföljde 41 deltagare GIH:s hälsotester, av dem var 20 kvinnor och 21 män mellan 30-49 år. Det enda som krävdes för att delta var att man uppfattade sig själv som frisk. Personer som tidigare haft stroke, hjärtinfarkt eller opererats på grund av hjärtproblem har inte inkluderats, ej heller gravida och personer med ledbesvär. Testerna utfördes på LTIV (Laboratoriet för tillämpad idrottsvetenskap) mellan februari och mars 2016. Resultat Signifikanta skillnader mellan de två separata testtillfällena noterades för några av styrketesterna framför allt hos männen: axelpressar, handgrip och stolresningar. Mellan könen sågs signifikanta skillnader i de antropometriska måtten, samt i flera konditions- och styrketester. Bland dessa kunde signifikant högre värden ses för kvinnorna än för männen i ryggstyrketestet.  Signifikanta skillnader mellan åldersgrupperna 30-39 år och 40-49 år sågs näst intill endast för kvinnor. De yngre jämfört med de äldre kvinnorna presterade bättre i flera av testerna, de vägde mindre och hade mindre kroppsmått. Slutsats Det framkom vanligtvis inte några signifikanta skillnader mellan det första och andra testtillfället, med enstaka undantag. När så är fallet behövs bara ett test utföras initialt inför en period med exempelvis fysisk aktivitet som senare kanske ska följas upp med ett återtest. Skillnader mellan könen och olika åldersgrupper framkom i vissa tester men inte i alla. Resultaten i denna studie beror bland annat på urvalet av individer. Eftersom att syftet med den här studien har varit att endast utföra de tester som ingår i GIH:s hälsotester har inga tester lagts till eller exkluderats. I arbetet diskuteras bland annat hur optimala testerna är som ett mått på hälsa. För att effektivisera hälsotestundersökningar framöver behöver nödvändigtvis inte alla tester utföras.

Title: Monitoring of influence of individual segments of a teaching unit of physical education on fitness of girls from seventh grade of elementary school. Aim: The aim of the empirical part is to monitor the proportional representation of the motoric activities during the time given in the lessons of physical education of the seventh grade girls, and along with the chosen methods of testing of these individuals, to prove or disprove possible influence of the composition of the P.E. lessons on the chosen segments of their fitness. Methods: Various methods were used for testing the considered sample. These were the standardized motoric tests (intense forward bend when sitting, place-jump with legs together, endurance in a pull-up, hand grip) which investigate the chosen segments of the fitness. Another method used was the bioimpedance which measures the parameters of body composition. The data were recollected quantitatively and the results were also processed quantitatively by means of statistic parameters, such as arithmetic mean, variation span and determinative deviation. Results: From the results of the work emerged that as far as the chosen motoric activities and their influence on the chosen segments of the fitness are concerned, during the time given only the segment of flexibility in...

In many occupations, exposure to hand-transmitted vibration (HTV) over a prolonged period causes various disorders involving the vascular, neural and musculoskeletal systems, collectively known as the hand-arm vibration syndrome (HAVS). It is a complex and potentially disabling chronic disorder of the upper extremities, especially of the hands. Numbness, tingling, reduced tactile discrimination, and impaired manipulative dexterity are often reported by workers exposed to HTV. The precise pathophysiological mechanism responsible for vascular injuries in HAVS has not yet been fully clarified; it seems to be multifactorial and highly complex. Interaction of neural signals, hormones, mediators and changes in the blood vessel itself appear to contribute to the development of such vascular injuries. This study aims to assess the risk of the hand-transmitted vibration exposure during pneumatic impact wrench operation in a rock drill repair and maintenance workshop at a South African platinum mine. A total of 8 workers working on a day to day basis with impact wrenches were available for this study. For each of the workers a control (not exposed to vibration) was selected on the basis of gender, ethnic group, smoking habits, age and body mass index (BMI). Grip force, dexterity and hand-eye co-ordination were tested on the workers and control group before and after work. Finger systolic blood pressure (FSBP) was also measured after cold provocation of the worker and control groups. Results have shown astatistically significant difference between the two groups with respect coordination, dexterity and FSBP after cold provocation. Vibration measurements shows three workers had values above the suggested ELV of 5 m/s² for an eight hour A (8) workday. With regards to dexterity, workers were capable to manipulate small objects better with their dominant right (vibration exposed) hand after work than before work. In contrast, it seems that the number of pegs correctly inserted by the controls is not uniformly affected by their 8 hour workday. The worker group showed a greater grip force than that of the control group, both before and after work.There was a statistically significant difference between the control and worker group with respect to the number of mistakes during the mirror trace and the time to complete this test only for the right hand. The difference in FSBP after cold provocation between the control and worker group observed is of medium importance when compared with effect sizes, however, there was no statistical significant difference. In this study, it was very difficult to make valid conclusions due to the limitations of a small sample size. A longitudinal study should be conducted preferably using newly appointed workers with no prior exposure to vibration and a sufficient control group to eliminate the effect other confounding variables such as general working conditions. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.

In many occupations, exposure to hand-transmitted vibration (HTV) over a prolonged period causes various disorders involving the vascular, neural and musculoskeletal systems, collectively known as the hand-arm vibration syndrome (HAVS). It is a complex and potentially disabling chronic disorder of the upper extremities, especially of the hands. Numbness, tingling, reduced tactile discrimination, and impaired manipulative dexterity are often reported by workers exposed to HTV. The precise pathophysiological mechanism responsible for vascular injuries in HAVS has not yet been fully clarified; it seems to be multifactorial and highly complex. Interaction of neural signals, hormones, mediators and changes in the blood vessel itself appear to contribute to the development of such vascular injuries. This study aims to assess the risk of the hand-transmitted vibration exposure during pneumatic impact wrench operation in a rock drill repair and maintenance workshop at a South African platinum mine. A total of 8 workers working on a day to day basis with impact wrenches were available for this study. For each of the workers a control (not exposed to vibration) was selected on the basis of gender, ethnic group, smoking habits, age and body mass index (BMI). Grip force, dexterity and hand-eye co-ordination were tested on the workers and control group before and after work. Finger systolic blood pressure (FSBP) was also measured after cold provocation of the worker and control groups. Results have shown astatistically significant difference between the two groups with respect coordination, dexterity and FSBP after cold provocation. Vibration measurements shows three workers had values above the suggested ELV of 5 m/s² for an eight hour A (8) workday. With regards to dexterity, workers were capable to manipulate small objects better with their dominant right (vibration exposed) hand after work than before work. In contrast, it seems that the number of pegs correctly inserted by the controls is not uniformly affected by their 8 hour workday. The worker group showed a greater grip force than that of the control group, both before and after work.There was a statistically significant difference between the control and worker group with respect to the number of mistakes during the mirror trace and the time to complete this test only for the right hand. The difference in FSBP after cold provocation between the control and worker group observed is of medium importance when compared with effect sizes, however, there was no statistical significant difference. In this study, it was very difficult to make valid conclusions due to the limitations of a small sample size. A longitudinal study should be conducted preferably using newly appointed workers with no prior exposure to vibration and a sufficient control group to eliminate the effect other confounding variables such as general working conditions. / Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013.