The master’s thesis deals with the computational modelling of the mechanical testing of isolated smooth muscle cells. The main aims are to create computational model of a cell, to simulate single-axis tensile test and to modify the model so that the model reflects real mechanical response. The model of the cell includes cytoplasm, nucleus, cell membrane and cytoskeleton which is modelled as a tensegrite structure. On this model the tensile test was simulated in case of the cell with cytoskeleton and the cell with distributed the cytoskeleton. Force-elongation curves, which were obtained from this simulation, were compared with experimental data which were taken from literature. Tensile properties were measured on freshly isolated cells from rat thoracic aorta, cultured cells, and cells treated with cytochalasin D to disrupt their actin filaments. It was found that the cytoskeleton influence on the cell load in computational model was smaller than in the real cell. Therefore the model was modified by changing material propreties and geometry so that the model of the cell corresponded with the different types of experimentally measured cells.

[pt] Esta pesquisa está inserida no universo dos portadores de necessidades especiais e pretende desenvolver uma nova tecnologia para projetar a estrutura de cadeira de rodas. Tal estrutura será composta por um módulo tensegrity composto de varas de bambu e cabos tensionados e adota todos os padrões antropométricos com a observância aos estudos ergonômicos e necessidades individuais de uso dos cadeirantes. Esse novo conceito de design de estrutura, por ser inédito, resulta num produto inovador e permite novas interpretações e desdobramentos. Essa pesquisa também inicia uma nova interpretação do tensegrity por sua aplicação a órteses para reabilitação que atualmente é amplamente difundido nas artes plásticas, arquitetura e no design de produto. O seu emprego pode suprir algumas necessidades como adaptação corporal favorável pela maleabilidade da estrutura que absorve os movimentos mais bruscos que possam causar incômodos, lesões e má acomodação do usuário à cadeira de rodas. / [en] This research is part of the universe of people with special needs and aims to develop a new technology to design the wheelchair frame. This structure will consist of a compound tensegrity module bamboo poles and tensioned cables and adopts all anthropometric standards with respect to ergonomic studies and individual needs of use of the wheelchair. This new concept of structure design, to be unheard of, resulting in an innovative product and allows new interpretations and developments. This research also initiates a new interpretation of tensegrity by its application to orthoses for rehabilitation that is currently widespread in art, architecture and product design. Your job can fill some needs as body adaptation favor the flexibility of the structure that absorbs the most sudden movements that may cause nuisance, injuries and poor user accommodation to the wheelchair.

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Once a year for over forty years public relations’ practitioners in Sweden gathers, the political week in Almedalen, in the town of Visby. There they exchange knowledge and experience on all types of subjects using different and common communication models whether they are aware of them or not. The research on communication models is sparse, with one exception: Grunig’s model. Both practitioners and researches believe them to be important, even strategic. But too little knowledge about the models as such negatively impacts the understanding of public relations’ activities. It also contributes to the view that public relations is frittered. The thesis studies and analyses communication models of public relations. Models have been created by theorists and practitioners to describe the phenomenon, to understand communication as such and to facilitate communication between humans. The thesis addresses basic questions such as which models there are, where they stem from, who the originators were and the characteristics of each respective model. The basis of the study is comprehensive Anglo-American literature. All in all, over twenty different models have been analyzed in three different ways, i.e. the structure of a model, its historical deposits (sediment) and the application of the model. The result is manifold, since many characteristics form ten attributes and three families of models (a reduction). The characteristics can be seen as the models’ building blocks, e.g. the direction of the communication, the number of contacts and synchronism. Three model families are built on three differentiating characteristics, and the families are named correspondingly. Directional model (Riktningsmodellen), the Co-orientational model (Saminriktningsmodellen) and the Connectivity model (Konnektivitetsmodellen). The classification is of course not set in stone. It should be regarded as a first step to reduce the number of models in use and concentrate on the important characteristics of the models that help public relations researchers and professionals to solve problems and theorists to explain, foresee or guide to better public relations. Finally, five areas of future research are presented: a multinational study of models, a study of practitioners’ model use, a deeper history study according the concept of sediment, a notational system for models and, last but not least, a development of the Connectivity model. The last subject is the one that once inspired me to write a thesis. / <p>QC 20170426</p>

Thesis (PhD)--Macquarie University. Macquarie Graduate School of Management. / Bibliography: p. 286-324. / The contribution of this thesis is to present a framework to analyse firms controlled by more than one board. The literature survey of Chapter 2 revealed that there is little recognition of this phenomenon and no accepted way to investigate firms governed by multiple control centres described as a "compound board". The framework is developed in Chapter 3. The historical emergence of compound boards is outlined in Chapter 4 with examples of their architecture described in Chapters 5 and 6. Chapter 7 shows how the framework provides insights not available from other theories of the firm and how selfyes governance can be furthered by utilising contrary human attributes of competition/co-operation, trust/suspicion and self-interest/altruism. / The framework is described as transaction byte analysis (TBA) as it is based on the limited and inconsistent ability of humans to transact units of information described as "bytes". TBA identifies cybernetic principles and strategies that can mitigate human limitations in processing bytes. These provide organisational design criteria for firms to obtain operating advantages. As information is a common element in varies theories of the firm, TBA relates and subsumes them while allowing any type of organisation to be analysed. / Propositions are presented in Chapter 7 for illustrating how TBA provides insights into explaining: (i) why non-trivial employee owned industrial firms have more than one board; (ii) why self-regulation and self-governance of non-trivial firms cannot be assured without a compound board; (iii) how compound boards can simplify the role, knowledge, duties and liabilities of directors; (iv) the competitive advantages of appropriate compound boards in relation to unitary control systems; (v) how to compare and evaluate the relative advantages and disadvantages of firms with different ownership and control structures; (vi) how to compare the relative efficacy of hierarchical and non-hierarchical firms be they in the private or public sector. / Mode of access: World Wide Web. / x, 324 p. ill

Buňka tvoří složitý biologický systém vystavený mnoha mimobuněčným mechanickým podnětům. Hlubší pochopení jejího mechanického chování je důležité pro charakterizaci její odezvy v podmínkách zdraví i nemoci. Výpočtové modelování může rozšířit pochopení mechaniky buňky, která může přispívat k vytvoření vztahů mezi strukturou a funkcí různých typů buněk v různých stavech. Za tímto účelem byly pomocí metody konečných prvků (MKP) vytvořeny dva bendotensegritní modely buňky v různých stavech: model vznášející se buňky pro analýzu její globální mechanické odezvy, jako je protažení nebo stlačení, a model buňky přilnuté k podložce, který vysvětluje odezvu buňky na lokální mechanické zatížení, jako třeba vtlačování hrotu při mikroskopii atomárních sil (AFM). Oba zachovávají základní principy tensegritních struktur jako je jejich předpětí a vzájemné ovlivnění mezi komponentami, ale prvky se mohou nezávisle pohybovat. Zahrnutí nedávno navržené bendotensegritní koncepce umožňuje těmto modelům brát v úvahu jak tahové, tak i ohybové namáhání mikrotubulů (MTs) a také zahrnout vlnitost intermediálních filament (IFs). Modely předpokládají, že jednotlivé složky cytoskeletu mohou měnit svůj tvar a uspořádání, aniž by při jejich odstranění došlo ke kolapsu celé buněčné struktury, a tak umožňují hodnotit mechanický příspěvek jednotlivých složek cytoskeletu k mechanice buňky. Model vznášející se buňky napodobuje realisticky odezvu síla-deformace během protahování a stlačování buňky a obě odezvy ilustrují nelineární nárůst tuhosti s růstem mechanického zatížení. Výsledky simulací ukazují, že aktinová filamenta i mikrotubuly hrají klíčovou úlohu při určování tahové odezvy buňky, zatímco k její tlakové odezvě přispívají podstatně jen aktinová filamenta. Model buňky přilnuté k podložce dává odezvu síla-hloubka vtlačení ve dvou různých místech odpovídající nelineární odezvě zjištěné experimentálně při AFM. Výsledky simulací ukazují, že pro chování buňky je rozhodující místo vtlačení a její tuhost určují aktinová povrchová vrstva, mikrotubuly a cytoplazma. Navržené modely umožňují cenný vhled do vzájemných souvislostí mechanických vlastností buněk, do mechanické úlohy komponent cytoskeletu jak individuálně, tak i ve vzájemné synergii a do deformace jádra buňky za různých podmínek mechanického zatížení. Tudíž tato práce přispívá k lepšímu pochopení mechaniky cytoskeletu zodpovědné za chování buňky, což naopak může napomáhat ve zkoumání různých patologických podmínek jako je rakovina a cévní choroby.

Applications of vibration structural health monitoring (VHM) techniques are increasing rapidly. This is because of the advances in sensors and instrumentation during the last decades. VHM uses the vibration properties to evaluate many civil structures during the design steps, building steps and service life. The stiffness and frequencies of tensegrity structures are primarily related to the level of pre-stress. The present work investigates the possibilities to use this relation in designing, constructing and evaluating the tensegrity structures. The first part of the  present work studies the improvement of current models for resonance frequency simulation of tensegrities by introducing the bending behaviour of all components, and by a one-way coupling between the axial force and the stiffness. From this, both local and global vibration modes are obtained. The resonance frequencies are seen as non-linearly dependent on the pre-stress level in the structure, thereby giving a basis for diagnosis of structural conditions from measured frequencies. The new aspects of tensegrity simulations are shown for simple, plane structures but the basic methods are easily used also for more complex structures. In the second part, the environmental temperature effects on vibration properties of tensegrity structures have been investigated, considering primarily seasonal temperature differences (uniform temperature differences). Changes in dynamic characteristics due to temperature variations were compared with the changes due to decreasing pre-tension in one of the cables. In general, it is shown that the change in structural frequencies made by temperature changes could be equivalent to the change made by damage (slacking). Different combinations of materials used and boundary conditions are also investigated. These are shown to have a significant impact on the pre-stress level and the natural frequencies of the tensegrity structures when the environment temperature is changed. / Användandet av vibrationsbaserade hälsokontrollsmetoder (VHM) för strukturer ökar snabbt.Detta har möjliggjorts av utvecklingen inom  mätmetoder och mätutrus- tning under de senaste decennierna.Dessa metoder använder sig av de uppmätta eller simulerade vibrationsegenskaperna  underdesign-, uppbyggnads- och  nyttjandestadierna hos många slag av byggnadsverk. Styvheten och resonansfrekvenserna hos tensegritets-strukturer är i hög grad beroendepå den aktuella förspänningsnivån. Föreliggande arbete undersöker möjlig- heterna attanvända detta beroende i konstruktion, byggande och utvärdering av sådana strukturer. Den första delen av  föreliggande arbete studerar förbättringar av de vanligen användamodellerna för simulering av resonansfrekvenser hos tensegritetsstrukturergenom att införa de ingående komponenternas böjningsegenskaper, och genom att i enriktning koppla normalkraften till böjstyvheten. Genom detta kan såväl lokala som globalavibrationsmoder hittas. Resonansfrekvenserna ses därmed som icke-linjärt beroende avförspänningsnivån i strukturen. Detta ger därmed möjligheter att diagnosticera strukturenskondition från uppmätta frekvenser. De nya simuleringsmöjligheternademonstreras för enkla, plana strukturer, men de utvecklade metoderna kan också lättanpassas till mera komplexa fall. Den andra delen av arbetet undersöker hur strukturernas vibrationsegenskaper ärberoende på temperatureffekter i omgivningen. I första hand beaktas säsongsvisa (likformiga)temperaturvariationer. Förändringar i de dynamiska egenskaperna beroende påtemperaturförändringar jämfördes med dem som beror på en minskande förspänning hos någonav de ingående kablarna. I allmänhet gäller att förändringarna i resonansfrekvenser kanvara av samma storleksordning som de som beror på skador (minskad förspänning).Olika kombinationer av material, och olika upplagsförhållanden undersöktes.Dessa egenskaper visades ha en betydande effekt på förspänningsnivån, och därmed ocksåpå resonansfrekvenserna, hos tensegritets-strukturerna som utsätts för temperaturvariationer. / <p>QC 20140514</p>

Researchers have offered a variety of solutions for overcoming the old and challenging problem of undesired vibrations. The optimum vibration-control solution that can be a passive, semi-active or active solution, is chosen based on the desired level of vibration-control, the budget and the nature of the vibration source. Mechanical vibration-control systems, which work based on variable stiffness control, are categorized as semi-active solutions. They are advantageous for applications with multiple excitation frequencies, such as seismic applications. The available mechanical variable stiffness systems that are used for vibration-control, however, are slow and usually big, and their slowness and size have limited their application. A new semi-active variable stiffness solution is introduced and developed in this thesis to address these challenges by providing a faster vibration-control system with a feasible size. The new solution proposed in this thesis is a semi-active variable stiffness mount/isolator called the antagonistic Variable Stiffness Mount (VSM), which uses a variable stiffness spring called the Antagonistic Variable stiffness Spring (AVS). The AVS is a kinematically singular prestressable mechanism. Its stiffness can be changed by controlling the prestress of the mechanisms links. The AVS provides additional stiffness for a VSM when such stiffness is needed and remains inactive when it is not needed. The damping of the VSM is constant and an additional constant stiffness in the VSM supports the deadweight. Two cable-mechanisms - kinematically singular cable-driven mechanisms and Prism Tensegrities - are developed as AVSs in this thesis. Their optimal configurations are identified and a general formulation for their prestress stiffness is provided by using the notion of infinitesimal mechanism. The feasibility and practicality of the AVS and VSM are demonstrated through a case study of a typical engine mount by simulation of the mathematical models and by extensive experimental analysis. A VSM with an adjustable design, a piezo-actuation mechanism and a simple on-off controller is fabricated and tested for performance evaluation. The performance is measured based on four criteria: (1) how much the VSM controls the displacement near the resonance, (2) how well the VSM isolates the vibration at high frequencies, (3) how well the VSM controls the motion caused by shock, and (4) how fast the VSM reacts to control the vibration. For this evaluation, first the stiffness of the VSM was characterized through static and dynamic tests. Then performance of the VSM was evaluated and compared with an equivalent passive mount in two main areas of transmissibility and shock absorption. The response time of the VSM is also measured in a realistic scenario.

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