This thesis takes a fresh approach to cochlear mechanics. Over the last quarter of a century, we have learnt that the cochlea is active and highly tuned, observations suggesting that something may be resonating. Rather than accepting the standard traveling wave interpretation, here I investigate whether a resonance theory of some kind can be applied to this remarkable behaviour.¶ A historical survey of resonance theories is first conducted, and advantages and drawbacks examined. A corresponding look at the traveling wave theory includes a listing of its short-comings.¶ A new model of the cochlea is put forward that exhibits inherently high tuning. The surface acoustic wave (SAW) model suggests that the three rows of outer hair cells (OHCs) interact in a similar way to the interdigital transducers of an electronic SAW device. Analytic equations are developed to describe the conjectured interactions between rows of active OHCs in which each cell is treated as a point source of expanding wavefronts. Motion of a cell launches a wave that is sensed by the stereocilia of neighbouring cells, producing positive feedback. Numerical calculations confirm that this arrangement provides sharp tuning when the feedback gain is set just below oscillation threshold.¶ A major requirement of the SAW model is that the waves carrying the feedback have slow speed (5-200 mm/s) and high dispersion. A wave type with the required properties is identified - a symmetric Lloyd-Redwood wave (or squirting wave) - and the physical properties of the organ of Corti are shown to well match those required by theory.¶ The squirting wave mechanism may provide a second filter for a primary traveling wave stimulus, or stand-alone tuning in a pure resonance model. In both, cyclic activity of squirting waves leads to standing waves, and this provides a physical rendering of the cochlear amplifier. In keeping with pure resonance, this thesis proposes that OHCs react to the fast pressure wave rather than to bending of stereocilia induced by a traveling wave. Investigation of literature on OHC ultrastructure reveals anatomical features consistent with them being pressure detectors: they possess a cuticular pore (a small compliant spot in an otherwise rigid cell body) and a spherical body within (Hensens body) that could be compressible. I conclude that OHCs are dual detectors, sensing displacement at high intensities and pressure at low. Thus, the conventional traveling wave could operate at high levels and resonance at levels dominated by the cochlear amplifier. ¶ The latter picture accords with the description due to Gold (1987) that the cochlea is an ‘underwater piano’ - a bank of strings that are highly tuned despite immersion in liquid.¶ An autocorrelation analysis of the distinctive outer hair cell geometry shows trends that support the SAW model. In particular, it explains why maximum distortion occurs at a ratio of the two primaries of about 1.2. This ratio also produces near-integer ratios in certain hair-cell alignments, suggesting that music may have a cochlear basis.¶ The thesis concludes with an evaluation and proposals to experimentally test its validity.

Kvinnlig ejakulation har på olika sätt skildrats sedan början av vår tideräkning och beskrivningar av den och av kvinnans sexualitet har varierat beroende på historisk kontext. Syftet med denna studie var att undersöka vilken roll forskning kan spela i att definiera den kvinnliga sexualiteten, med debatten om den kvinnliga ejakulationen mellan 1978-2018 som exempel. För att kontextualisera debatten har även feministiska skildringar under samma period inkluderats. Materialet har bestått av vetenskapliga artiklar, annan litteratur samt olika typer av internetkällor som berör den kvinnliga ejakulationen. Materialet har analyserats med hjälp av en foucauldiansk genealogisk diskursanalys, med socialkonstruktivism som grund. Debatten kan delas upp i tre diskursiva spår som följer varandra kronologiskt. Det första diskursiva spåret fokuserar på det forskningsfält som växte fram under 1980-talet där huvudsyftet var att normalisera och ge vetenskapligt underlag för den kvinnliga ejakulationen. Det andra diskursiva spåret skildrar hur företrädare för den sexpositiva feminismen anammade kvinnlig ejakulation som en symbol för makt över den egna kroppen och sexualiteten. Det tredje diskursiva spåret skildrar hur fenomenet återupptäcktes med hjälp av andra forskningsmetoder men också hur kvinnlig ejakulation beskrevs som en dysfunktion, vilket väckt starka motreaktioner utanför forskningsfältet. Trots att fenomenet är känt sedan lång tid tillbaka går uppfattningarna fortfarande isär och bilden av den kvinnliga ejakulationen varierar beroende på vilken sorts kunskap som har legitimitet. Förståelsen av kvinnlig ejakulation är starkt beroende av forskningens definition av den. Detta synliggörs när den kvinnliga ejakulationen går från att beskrivas som ett sexuellt fenomen till ett sjukligt till följd av att urinmarkörer uppmärksammats i den utsöndrade vätskan. Forskares agerande kan förstås som en patologisering av den kvinnliga sexualiteten. / Female ejaculation has been portrayed in various ways since the beginning of our era and descriptions of it and of women’s sexuality have varied depending on historical context. The aim of this study was to investigate the possible role of scientific research in defining female sexuality, with the debate on female ejaculation between 1978-2018 as an example. In order to contextualize the debate, the feminist portrayal during the same period has also been included. The material has consisted of scientific literature, other literature and various types of internet sources that refers to the female ejaculation. We analyzed the material using a Foucauldian genealogical discourse analysis, with social constructivism at the core. The debate can be divided into three discursive tracks that follow each other chronologically. The first discursive track focuses on the research field that emerged during the 1980s, in which the main intention was to normalize and provide scientific evidence for the female ejaculation. The second discursive track describes how representatives of sex-positive feminism embraced female ejaculation as a symbol of power over one’s own body and sexuality. The third discursive track portrays how the phenomenon was rediscovered using other research methods, but also how female ejaculation was described as a dysfunction, which caused strong counter-reactions outside of the scientific research field. Although this phenomenon has been known for a long time, perceptions still differ and the image of it varies depending on what kind of knowledge that is legitimate at a certain point in time. The understanding of female ejaculation is strongly dependent on definition of it in scientific research. This is made visible when the female ejaculation changes from being described as a sexual phenomenon to a diseased one due to the fact that urinary markers have been detected in the emission fluid. Scientists' actions can be understood as a pathologization of female sexuality.

A project developed during a magister´s study of a program M-STM Mechanical engineering and industrial management brings in a proposal of a technology of cold forging part out of 12 040 steel. The forging on a multi-stage processual automatic machine TPZK 25 with nominal forming power 5000 kN was projected based on consultations, study of literary resources a calculations.