Health and fitness sector is becoming increasingly popular, and technology is being integrated into the fitness industry. This project proposed to digitalise the smith machine by creating a system to generate force through an electric motor to replace free weights. Because the exercise machine no longer needs to be loaded and unloaded with free weights, digitalisation of the smith machine will allow several users to utilise the same training machine. It will also be possible to track users' training information, such as weight lifted and the number of sets and reps performed during a workout. In this thesis, an Electrical speed controller (ESC) called VESC was used to control the BLDC motor. Experiments were conducted to find a method to control the torque. The result was producing a constant torque with a margin of error of 1-1.5 kilograms. Furthermore, two algorithms were developed where the resistance varies during the path of motion, which indicates that it is possible to develop the system to individualise resistance to improve training performance and rehabilitation. The conclusion that could be drawn is that this system can be used to replace free weights with an electric motor. / Hälso- och fitness sektorn blir allt populärare ochtekniken integreras alltmer ifitnessbranschen. Detta projekt syftar på att digitaliserasmithmaskin genom att skapa ettsystem för att generera kraft genom en elmotor föratt ersätta fria vikter. Genom att ersättalösa vikter med en elmotor så slipper användaren hanteralösa vikter vilket också underlättarför flera användaren att använda samma träningsmaskin.Det kommer också vara möjligt attspåra användarnas träningsinformation, såsom vikt,antalet set och repetitioner som utförtsunder ett träningspass.I detta projekt användes en motorstyrenhet som heterVESC för att styra en BLDC-motor.Flertalet experiment utfördes för att hitta en metodför att kontrollera vridmomentet. Dettaresulterade till att ett konstant vridmoment med enfelmarginal på 1-1.5 kilogram uppnåddes.Dessutom utvecklades två algoritmer där motståndetvarierar dynamiskt, vilket indikerar attdet är möjligt att i framtiden utveckla systemet föratt individualisera motstånd och därmedförbättra resultatet i träning och rehabilitering.Slutsatsen som kan dras är att detta system kananvändas för att ersätta fria vikter med en elmotor.

Indiana University-Purdue University Indianapolis (IUPUI) / Investigations of a constant-volume combustor ignited by a penetrating transient jet (a puff) of hot reactive gas have been conducted in order to provide vital data for designing wave rotor combustors. In a wave rotor combustor, a cylindrical drum with an array of channels arranged around the axis spins at a high rpm to generate high-temperature and high-pressure product gas. The hot-gas jet ignition method has been employed to initiate combustion in the channels. This study aims at experimentally investigating the ignition delay time of a premixed combustible mixture in a rectangular, constant-volume chamber, representing one channel of the wave rotor drum. The ignition process may be influenced by the multiple factors: the equivalence ratio, temperature, and the composition of the fuel mixture, the temperature and composition of the jet gas, and the peak mass flow rate of the jet (which depends on diaphragm rupture pressure). In this study, the main mixture is at room temperature. The jet composition and temperature are determined by its source in a pre-chamber with a hydrogen-methane mixture with an equivalent ratio of 1.1, and a fuel mixture ratio of 50:50 (CH4:H2 by volume). The rupture pressure of a diaphragm in the pre-chamber, which is related to the mass flow rate and temperature of the hot jet, can be controlled by varying the number of indentations in the diaphragm. The main chamber composition is varied, with the use of four equivalence ratios (1.0, 0.8, 0.6, and 0.4) and two fuel mixture ratios (50:50, and 30:70 of CH4:H2 by volume). The sudden start of the jet upon rupture of the diaphragm causes a shock wave that precedes the jet and travels along the channel and back after reflection. The shock strength has an important role in fast ignition since the pressure and the temperature are increased after the shock. The reflected shock pressure was examined in order to check the variation of the shock strength. However, it is revealed that the shock strength becomes attenuated compared with the theoretical pressure of the reflected shock. The gap between theoretical and measured pressures increases with the increase of the Mach number of the initial shock. Ignition delay times are obtained using pressure records from two dynamic pressure transducers installed on the main chamber, as well as high-speed videography using flame incandescence and Schileren imaging. The ignition delay time is defined in this research as the time interval from the diaphragm rupture moment to the ignition moment of the air/fuel mixture in the main chamber. Previous researchers used the averaged ignition delay time because the diaphragm rupture moment is elusive considering the structure of the chamber. In this research, the diaphragm rupture moment is estimated based on the initial shock speed and the longitudinal length of the main chamber, and validated with the high-speed video images such that the error between the estimation time and the measured time is within 0.5%. Ignition delay times decrease with an increase in the amount of hydrogen in the fuel mixture, the amount of mass of the hot-jet gases from the pre-chamber, and with a decrease in the equivalence ratio. A Schlieren system has been established to visualize the characteristics of the shock wave, and the flame front. Schlieren photography shows the density gradient of a subject with sharp contrast, including steep density gradients, such as the flame edge and the shock wave. The flame propagation, gas oscillation, and the shock wave speed are measured using the Schlieren system. An image processing code using MATLAB has been developed for measuring the flame front movement from Schlieren images. The trend of the maximum pressure in the main chamber with respect to the equivalence ratio and the fuel mixture ratio describes that the equivalence ratio 0.8 shows the highest maximum pressure, and the fuel ratio 50:50 condition reveals lower maximum pressure in the main chamber than the 30:70 condition. After the combustion occurs, the frequency of the pressure oscillation by the traversing pressure wave increases compared to the frequency before ignition, showing a similar trend with the maximum pressure in the chamber. The frequency is the fastest at the equivalence ratio of 0.8, and the slowest at a ratio of 0.4. The fuel ratio 30:70 cases show slightly faster frequencies than 50:50 cases. Two different combustion behaviors, fast and slow combustion, are observed, and respective characteristics are discussed. The frequency of the flame front oscillation well matches with that of the pressure oscillation, and it seems that the pressure waves drive the flame fronts considering the pressure oscillation frequency is somewhat faster. Lastly, a feedback mechanism between the shock and the flame is suggested to explain the fast combustion in a constant volume chamber with the shock-flame interactions.

Indiana University-Purdue University Indianapolis (IUPUI) / This study contributes to a better working knowledge of the equipment being used in a well-established combustion lab. In particular, several constant-volume combustion properties (e.g., time ignition delay, flame propagation, and more) are examined to deduce any buoyancy effects between fuel and air mixtures and to develop a method aimed at minimizing such effects. This study was conducted on an apparatus designed to model the phenomena occurring within a single channel of a wave rotor combustor, which consists of a rotating cylindrical pre-chamber and a fixed rectangular main combustion chamber. Pressure sensors monitor the internal pressures within the both chambers at all times, and two slow-motion videography techniques visually capture combustion phenomena occurring within the main chamber. A new recirculation pump system has been implemented to mitigate stratification within the chamber and produce more precise, reliable results. The apparatus was used in several types of experiments that involved the combustion of various hydrocarbon fuels in the main chamber, including methane, 50%-50% methane-hydrogen, hydrogen, propane, and 46.4%-56.3% methane-argon. Additionally, combustion products created in the pre-chamber from a 1.1 equivalence ratio reaction between 50%-50% methane-hydrogen and air were utilized in the issuing pre-chamber jet for all hot jet ignition tests. In the first set of experiments, a spark plug ignition source was used to study how combustion events travel through the main chamber after different mixing methods were utilized – specifically no mixing, diffusive mixing, and pump circulation mixing. The study reaffirmed that stratification between fuel-air mixtures occurs in the main chamber through the presence of asymmetrical flame front propagation. Allowing time for mixing, however, resulted in more symmetric flame fronts, broader pressure peaks, and reduced combustion time in the channel. While 30 seconds of diffusion helped, it was found that 30 seconds of pumping (at a rate of 30 pumps per 10 seconds) was the most effective method at reducing stratification effects in the system. Next, stationary hot jet ignition experiments were conducted to compare the time between jet injection and main chamber combustion and the speed of the resulting shockwaves between cases with no mixing and 30 seconds of pump mixing. Results continued to show an improvement with the pump cases; ignition delay times were typically shorter, and shock speeds stayed around the same, if not increased slightly. These properties are vital when studying and developing wave rotor combustors, and therefore, reducing stratification (specifically by means of a recirculation system) should be considered a crucial step in laboratory models such as this one. Lastly, experiments between a fueled main chamber and rotating pre-chamber helped evaluate the leakage rate of the traversing hot jet ignition experimental setup paired with the new pump system. In its current form, major leaks are inevitable when attempting traversing jet experiments, especially with the pump’s suction action drawing sudden large plumes of outside air into the main chamber. To minimize leaks, gaps between the pre-chamber and main chamber should be reduced, and the contact surface between the two chambers should be more evenly distributed. Also, the pump system should only be operated as long as needed to evenly distribute the fuel-air mixture, which approximately happens when the main chamber’s total volume has been circulated through the system one time. Therefore, a new pump system with half of the original system’s volume was developed in order to decrease the pumping time and lower the risk of leaks.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18992号 / 工博第4034号 / 新制||工||1621(附属図書館) / 31943 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 篠原 真毅, 教授 和田 修己, 教授 山川 宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20413号 / 工博第4350号 / 新制||工||1674(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 宮原 稔, 教授 田門 肇, 教授 山本 量一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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In Statement No. 33, "Financial Reporting and Changing Prices," the FASB requires that some large companies disclose their historical cost/constant dollar and current cost information in the published financial statements. One of the purposes of these disclosures is to help users of the financial statements in assessing future cash flows. This study was directed toward the examination of the effects of the different levels of disclosures on cash flow projections.

This paper comprehensively examines a new type of social media influencer characterized by altruistic tendencies. Utilizing the popular YouTube channel Vlogbrothers as the case study text for a constant comparative analysis, this research explores how the strategies altruistic influencers use to mobilize their community for good, the characteristics of the altruistic influencers, and how altruistic influencers create community. Through an in-depth analysis of 30 Vlogbrothers videos, the themes of education, community, and shared humanity emerged. Education, shared values, and calls to action are discussed as essential for mobilizing communities in charitable endeavors. Authenticity, quality, accessibility, and solutions-focused action were found to be vital characteristics of altruistic influencers. Structure, collaboration, multi-format content, parasocial relationships, and traditions are discussed as community-building tools for altruistic influencers. This research contributes to the existing literature on corporate social responsibility and purpose-driven organizations within the realm of social media influencers. Furthermore, it introduces the concept of "altruistic influencer" as a distinct category within this literature. By outlining the key characteristics and strategies observed in altruistic influencers, this study provides a valuable framework for other influencers to model and encourages further exploration of this field.

The circadian system is a mechanism designed to generate circadian time and to synchronize it with the solar cycle. Its function is to adjust to behavioral and physiological function with the 24-hour period. The adjustment is performed using a so-called zeitgeber or synchronizer. The main circadian clock is in the suprachiasmatic nuclei (SCN) in the hypothalamus. Prolonged exposure of the organism to constant light conditions results in desynchronization of the circadian clock, which can lead to many pathologies. The impact of light at night on the organism has been studied for a long time, but the question of the impact of constant light on the development of the circadian system of the organism has been less studied. My thesis deals with this issue. Using RT-qPCR I investigated how the rhytm changes in the expression of selected clock genes in selected parts of the rat's brain, which has been kept in constant light sice birth. I also tested the impact of exposure to constant light on the early development of rhytm in locomotor activity later in the rat's life. Keywords: circadian system, photic entrainment, desynchronization under constant light, development, rat