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Alternative reproductive tactics (ARTs), occur where members of one sex of a species have two or more strategies of obtaining fertilization. The tactics differ in behavioural approaches to reproduction, but also commonly differ in physiological and morphological traits. The round goby, Neogobius melanostomus, is a globally invasive species with male ARTs. How behaviour may influence invasiveness in round goby has been of recent interest, but researchers have not considered the role or impact that male ARTs may have. I compared guarder and sneaker male round goby, assessing differences in their boldness, activity, exploration, sociality, aggression, startle responses, and dispersal tendencies. Sneaker males were more bold, active, and explorative while guarder males were more aggressive. In addition, I studied whether more guarders or sneakers are caught in a population survey study and how variation in a common round goby trapping method, minnow traps, may create catch biases. Two commonly employed minnow trap models include a black vinyl plastic coated metal trap (black traps) and a galvanized metal steel trap (silver traps). I investigated whether these black and silver traps and baited (corn) and unbaited traps differ in terms of the numbers, ART ratios, and sizes of round goby captured. I found silver traps captured 1.7 times more round goby than black traps, while baited traps captured 3.4 times more round goby than unbaited traps. Baited traps captured larger round goby and tended to capture more guarders than unbaited traps. I also found black traps captured larger males, but there was no difference in the size of females captured. Taken together my results indicate that care needs to be applied when making estimates of round goby populations in terms of the types of individuals present and the trapping method used. / Thesis / Master of Science (MSc)

The production of faulty parts poses significant challenges for production facilities, as it leads to increased inventory levels, operating costs, and impedes overall productivity. Despite its fundamental nature, this issue remains prevalent in manufacturing operations. To effectively reduce the rate of faulty parts, it is crucial to have a thorough understanding of the manufacturing process and exercise control by monitoring various parameters.  The aim of this study is to investigate the right prerequisites which enable quality assurance through in-line failure detection by vibration analysis. The research questions formulated for this thesis are as follows:  RQ1: What are the essential prerequisites for quality assurance through in-line failure detection by vibration analysis in the machining of splines? RQ2: How suitable is the use of vibration measurements in identifying and sorting out poor quality in the specific machining process of splines? The study was conducted through a literature review and a single case study of a gear hobbing process in an industrial manufacturing company.  The collection of data was acquired via interviews, observations, and vibration measurements during the spline manufacturing process. To analyse the collected data several tools got used. Python was used as the tool for performing several operations on the dataset, such as FFT of the vibration signals. To later visualize the results which facilitated the analysis of the entire dataset.  The results of the study indicate several similarities between the documented fault progression in gear systems and the manufacturing of splines. However, further research is needed to identify the core differences between these two fault progressions.  Furthermore, the study identified the essential prerequisites for implementing vibration analysis as an in-line failure detection method in spline manufacturing operations. Additionally, it concluded on the suitability of vibration analysis for identifying faults in this context.

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No description available.

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Research in developing a Positively Engaged Continuously Variable Transmission (PECVT) has been underway at Brigham Young University for some time. The inherent problems associated with embodiments of this type of transmission, namely the Non-Integer Tooth Problem (NITP), have been identified. This research is focused on the development of a Positively Engaged Piecewise Continuous Transmission (PEPCT), which is a subset of the PECVT. This document describes the hypothesis and analysis of using non-circular gearsets to overcome the NITP. This proposed solution enables a varying angular output from a constant angular input. In this research two analytical methods were evaluated based on their theory, mathematics and simulated results. Haupt's concept is shown to have discrepancies between the theorized and mathematical results which produce a gearset that has velocity spikes in its output. The second method, proposed by Danieli, describes the behavior on an infinitesimal level and the theorized results match up with the mathematical result. As a result of the analysis, Danieli's method is declared to produce a varying output from a constant input. The method requires only the definition of an input function that defines the shape of the pitch line similar to the pitch circle for circular gears. Using this function an infinitesimal approach is used to describe the interaction of consecutive contact points on the tooth profiles. This interaction takes into consideration adapted principles that are derived from the Fundamental Law of Gearing and the Law of Conjugate Action. With these principles defined it is possible to design gearsets that are capable of producing a varying angular output from a constant angular input. With the validation of the second method, and the principles defined by which it is governed, the proposed gearset is achievable allowing a PEPCT to be conceived. The proposed transmission utilizes the non-circular gearset to accelerate a secondary shaft to the next desired ratio while maintaining constant engagement. This concept is then analyzed and recommendations are made for the development of a Positively Engaged Continuously Variable Transmission.