Academic literature on the topic 'Tilt locking'

Abstract To evaluate and precisely internal fix intra-articular distal radial fracture (IDRF) using the virtual X-ray and three-dimensional (3D) printing technologies. Twenty-one patients with IDRF were recruited, and the data from digital design group (DDG) and real surgery group (RSG) were collected and analyzed. In DDG, the data from thin-slice computed tomography scan, virtual X-ray measurement parameters, including volar tilt, palmar tilt, radius length (D1), ulnar variation (D2), locking plate position parameter (D3) and distance between key nail and joint surface (D4) were collected. The bone was virtually fixed with the locking plate, and the final model of radius with the screw was obtained by 3D printing. In RSG, the locking plate was precisely pre-bended and used in surgery. During the surgery, the key K-wire was accurately placed and the locking plate was adjusted with the aid of the U-shaped navigation arm. The C-arm was used to observe the positions of key K-wires and the locking plate, and the same above-mentioned parameters were measured intra- and post-operatively. The data from RSG and DDG were compared statistically by t test. This approach proved to be successful in all 21 patients, and none of the screws pierced through the wrist joint surface. All the measured parameters, including the volar tilt, palmar tilt, D1–4, in RSG were not significantly different from preoperative DDG data. Virtual X-ray measurement of anatomical reduction parameters and 3D printing can help the anatomical reduction and precise internal fixation by providing quantitative references, preoperatively, intraoperatively and postoperatively.

Spiral or wedge-type leveling mechanism used by traditional theodolite, leveling between the cradle and the institutions, agencies and land leveling substrates are often unable to lock, and therefore can not afford to reverse the drive torque, and poor stability of the leveling means. Leveling device of this article, when the tilt table, the table with the solid sphere slider associated spherical rotary swing for the next slider to adjust the three leveling device to achieve leveling table. After leveling the table, under the action of the locking mechanism, the locking slide around the sphere spherical under lock slider rotation, lock nut and locking slider to achieve the sphere spherical self-centering locking to ensure leveling stability state.

This study compared the effectiveness of locking and non-locking palmar plating for unstable Colles’ fractures in the elderly. The patients treated with locking plates included 4 men and 18 women with a mean age of 68 years (Group A) and those treated with non-locking plates included 3 men and 28 women with a mean age of 74 years (Group B). Radiographic parameters, including palmar tilt, radial inclination and radial length were measured before surgery, after surgery and at final followup. There were no significant differences in respect of any of the radiographic parameters between the two groups pre-operatively. After surgery, all of the radiographic parameters were improved in both groups and there were no significant differences between the two groups at final followup.

Hydrostatic spindles are widely used in precision optical grinder and lathe. Their high precision comes from the error averaging effect of oil film. The purpose of this paper is to give the quantitative analysis of the error averaging effect for a newly developed axial locking-prevention hydrostatic spindle. An approximate error motion model of the hydrostatic spindle is established to analyze the internal relationship between the geometric errors of the shaft and the error motions of the spindle including radial, tilt and axial error motions. The theoretical analysis shows that, the roundness errors of the two journals have a major impact on error motions while the coaxiality errors of two journals, the perpendicularity errors of front thrust plate and the coaxiality errors of the land of back thrust bearing, have no significant influences on error motions. The elliptical component of roundness errors of the two journals has significant influence on the axial error motion but no influence on the pure radial and tilt error motions, resulting into the fourth harmonic component of axial error motion. The trilobal component of roundness errors of the two journals has significant influence on the pure radial and tilt error motions but no influence on the axial error motion, resulting in the third harmonic component of pure radial and tilt error motions. The changes of recess pressures are not necessary condition for the error motions. Additionally, the experiment analysis shows that, the third harmonic component is the main part of the measured radial error motion and the third, fourth harmonic components are the main parts of the measured face error motion, which can be reasonably explained by the theory. The model proposed in this paper can be used to guide the precision design and optimization of hydrostatic spindle.

Volar locking plate fixation has been widely accepted method for the treatment of unstable distal radius fractures. Although the results of volar locking plate fixation are encouraging, it may cause implant-related complications such as flexor or extensor tendon injuries. In depth understanding of anatomy of the distal radius is mandatory in order to obtain adequate fixation of the fracture fragments and to avoid these complications. This article will review the anatomic characteristics of the distal radius because selecting proper implant and positioning of the plate is closely related to the volar surface anatomy of the distal radius. The number and the length of distal locking screws are also important to provide adequate fixation strength to maintain fracture fixation. We will discuss the pros and cons of the variable-angle locking plate, which was introduced in an effort to provide surgeons with more freedom for fixation. Finally, we will discuss about correcting radial length and volar tilt by using eccentric drill holes and distal locking first technique.

In this thesis we investigate advanced techniques for the readout and control of various interferometers. In particular, we present experimental investigations of interferometer configurations and control techniques to be used in second generation interferometric gravitational wave detectors. We also present a new technique, tilt locking, for the readout and control of optical interferometers. ¶ We report the first experimental demonstration of a Sagnac interferometer with resonant sideband extraction (RSE). We measure the frequency response to modulation of the length of the arms and demonstrate an increase in signal bandwidth of by a factor of 6.5 compared to the Sagnac with arm cavities only. We compare Sagnac interferometers based on optical cavities with cavity-based Michelson interferometers and find that the Sagnac configuration has little overall advantage in a cavity-based system. ¶ A system for the control and signal extraction of a power recycled Michelson interferometer with RSE is presented. This control system employs a frontal modulation scheme requiring a phase modulated carrier field and a phase modulated subcarrier field. The system is capable of locking all 5 length degrees of freedom and allows the signal cavity to be detuned over the entire range of possibilities, in principle, whilst maintaining lock. We analytically investigate the modulation/demodulation techniques used to obtain these error signals, presenting an introductory explanation of single sideband modulation/demodulation and double demodulation. ¶ This control system is implemented on a benchtop prototype interferometer. We discuss technical problems associated with production of the input beam modulation components and present several solutions. Operation of the interferometer is demonstrated for a wide range of detunings. The frequency response of the interferometer is measured for various detuned points and we observe good agreement with theoretical predictions. The ability of the control system to maintain lock as the interferometer is detuned is experimentally demonstrated. ¶ Tilt locking, a new technique to obtain an error signal to lock a laser to an optical cavity, is presented. This technique produces an error signal by efficient measurement of the interference between the TEM00 and TEM10 modes. We perform experimental and theoretical comparisons with the widely used Pound-Drever-Hall (PDH) technique. We derive the quantum noise limit to the sensitivity of a measurement of the beam position, and using this result calculate the shot noise limited sensitivity of tilt locking. We show that tilt locking has a quantum efficiency of 80%, compared to 82% for the PDH technique. We present experimental demonstrations of tilt locking in several applications including frequency stabilisation, continuous-wave second harmonic generation, and injection locking of a Nd:YAG slab laser. In each of these cases, we demonstrate that the performance of tilt locking is not the limiting factor of the lock stability, and show that it achieves similar performance to the PDH based system. ¶ Finally, we discuss how tilt locking can be effectively applied to two beam interferometers. We show experimentally how a two beam interferometer typically gives excellent isolation against errors arising from changes in the photodetector position, and experimentally demonstrate the use of tilt locking as a signal readout system for a Sagnac interferometer.

Les lasers stabilisés à long terme sont utilisés dans de nombreux domaines en métrologie, leur incursion dans les applications spatiales se précise depuis quelques années, missions de physique fondamentale, géodésie... Ce travail concerne les lasers stables pour le projet LISA (détection spatiale des ondes de gravitation, mission prévue dans 10 ans); en vue de cette application spatiale, les montages doivent satisfaire plusieurs critères: compacité, stabilité mécanique, robustesse et fiabilité. Les références utilisables pour l'asservissement long terme (iode, chapitre 3) et court terme (cavité de Fabry-Pérot, chapitre 4) sont décrites, ainsi que leurs limitations principales. L'analyse et le choix de ces références de stabilisation seront couplés avec le choix des techniques de stabilisation (PDH, Tilt-Locking, Modulation Transfer). Dans les techniques de stabilisation, celle de Pound-Drever-Hall (PDH), un classique en matière de configuration, est comparée au Tilt-Locking, une technique continu et peu consommatrice en énergie, dans le cas d'une référence Fabry-Perot monolithique. Les calcules théorique pour chaque technique et chaque type de référence ammeneront à une description des sources de bruit et à une simulation des signaux d'erreur attendus. Les performances théoriques sur le long terme et les efficacités quantiques sont intercomparées. La deuxième partie, présentera les montages expérimentaux et les résultats obtenus, pour des lasers stabilisés sur Fabry-Perot et sur l'Iode moléculaire. Pour calibrer les dérives de fréquence du Fabry-Perot, sa fréquence de résonance sera mesurée par rapport à celle de la molécule, ce qui permettra de présenter des solutions obtenues analytiquement et numériquement pour l'asservissement en longueur de cette référence mécanique. En appendices, les détails de dimensionnement des bruits de LISA conduisant aux spécifications des lasers, le rappel théorique des ondes de gravitation ainsi que divers simulations de calculs effectués.

Vår uppsats syftar till att undersöka hur kapitalvinstbeskattningen på fastigheter och amorteringskraven på de lån som tas påverkar rörligheten på bostadsmarknaden idag. Vi kunde se att ämnet ofta är med i debatt men att det ändå inte utförts mycket studier i Sverige men det visade sig finnas studier som gjorts i USA. Vi har i vår studie på ett liknande sett valt att studera hur amorteringskravens införande påverkat bostadspriserna och hushållens utgifter genom att vi jämfört statistik, innan respektive efter dessa regleringars införande. Vi har valt att fokusera på enskilda fall då vi selektivt har valt ut 17 kommuner att undersöka. Detta kan beskrivas som en ”multiple case study” där vi vid varje enskilt fall gör en kvantitativ analys genom insamlad data. Det finns enligt teorin flertalet olika sorters inlåsningseffekter, exempelvis då hushåll aktivt väljer att undvika kostnader då deras nya boende kommer leda till högre månadskostnader efter flytt. Den data vi samlat in visar på att det i flertalet av de studerade kommunerna blir en betydande kostnad som uppkommer då individer väljer att flytta. Med tanke på den prisutveckling som skett på både bostadsrätter och villor över de senaste 20 åren borde respektive hushåll behöva låna mer pengar och därmed dra på sig högre kostnader även om de väljer att flytta till en mindre bostad. Teorin nämner ekonomiska inlåsningseffekter och inom dessa är vinstdriven inlåsning något som uppstår i samhällen som är liberala och globaliserade. Vår empiri visar på att de individer som bott en längre tid i en villa har fått en kraftig värdeökning på sina bostäder. Detta innebär att de behöver skatta mer, vilket är att se som en kostnad, vilket gör att de tjänar mindre när de säljer sina bostäder. Ökade skattekostnader leder enligt teorin till att benägenheten att flytta minskar. För varje 1000 USD, ca 10 000 kronor, som skattekostnader ökar minskar individens och hushållens benägenhet att flytta med 1 procent. Genomsnittet för de 17 studerade kommunerna ligger på ca 369 000 kronor vilket då borde innebära en minskning i benägenhet att flytta med 36,9 procent. Då tanken med amorteringskraven är att hushåll inte ska belåna sig lika högt som tidigare så kommer folk att bli mer restriktiva i sitt lånande vilket då gör att priserna kommer falla. Detta kommer innebära att de som köpt bostäderna då inte vill sälja eftersom de gör en förlust vilket i globalt och liberalt samhälle är ett vardagligt tänk. Därmed finns det inga bostäder som kan tänkas att säljas, flyttkedjornas rörlighet hämmas och inlåsningseffekter uppstår. Vår insamlade data visar på att det första amorteringskravet hade den efterfrågade effekten till viss del då priserna innan, under och kort efter just själva införandet av det första amorteringskravet minskade. Detta är dock mer påtagligt för bostadsrätter där det tydligt framgår att priserna per kvadratmeter sjönk medann K/T-talet för villor, trots att även kvadratmeterpriserna för dessa sjönk, låg kvar på mer stabila nivåer. Det tolkar vi som om att de skatteregler och amorteringskrav som finns idag leder till att folk inte vill flytta då de drar på sig stora kostnader vid en eventuell flytt. Både direkta, vinstskatten, men också retroaktiva i form av ökade månadskostnader.
This thesis analyzes the capital income taxes on real estate and the amortization of loans whether it will have an effect on the real estate market. The topic is up for debate but still not many studies have been made in Sweden. We found studies in the USA and have conducted our research in a similar way of studying the effects of the amortization requirements effect on the accommodation price and households costs. This is done by comparing statistics before and after the amortization requirements have been imposed. We decided to focus on specific cases and have chosen 17 different municipalities to look into. Our research can be described as a multiple case study where every individual case becomes a quantitative analysis though collected data. Different lock-in effects can be found and for example when a household chooses to avoid costs since a new house will lead in to higher monthly costs. The collected data shows that a majority of the municipalities will have significant increase in costs due to the development of both apartments and villas over the past 20 years. This results in higher loans and cost of moving, even when moving to a smaller accommodation. In the theory, we talk about economic lock-in effects due to a profit driven economy that arises in communities that are liberal and globalized. Our research show that people who have lived in their home for a long time have an accreted value. This accreted value leads to high taxes which can be seen as a cost that will make them earn less when trying to sell their home. Increased capital income taxes will lead to less tendency to move. For every 1000 USD a household pays in property taxes, the likelihood they will move decreases by 1 percent. The average capital gains taxation  of the municipalities studied is 369 000 SEK, which implies the households are less likely to move by 36.9 percent. The idea of amortization requirements is that households should not take as big loans as they would have done before so that people will be more restrictive while taking loans that will lead to falling house prices. This would lead to people who already own their homes to not sell since they will lose money, which in a global and liberal community is a colloquial thought. The result of this is: no housing for sale and the moving chain stops, thus the lock-in effects is inevitable. Our collected data shows that the first amortization requirements had the requested effect on the price before, under and for a short period of time after the imposition decline. However the effect is more significant on dwellings where falling square-meter prices clearly appears while the K/T numbers for houses dropped but still remains stable. We infer the tax law and amortization requirements today will lead to less people moving since it will result in increased costs with a potential move. Both direct, capital income taxes but also retroactive monthly costs.

In this thesis we investigate advanced techniques for the readout and control of various interferometers. In particular, we present experimental investigations of interferometer configurations and control techniques to be used in second generation interferometric gravitational wave detectors. We also present a new technique, tilt locking, for the readout and control of optical interferometers. ¶ ...

Retinopathy of Prematurity, caused by abnormal blood vessel development in the retina of premature infants, is a leading cause of childhood blindness. It is treated using laser photocoagulation. Current methods require the surgeon to assume awkward standing positions, which can result in injury to the surgeon if repeated often. To assist surgeons in providing quality care and prevent occupational injury, a new infant surgical table was designed. The engineered solution is an attachment to a standard surgical table, saving cost and space. This takes advantage of the adjustable height and tilt provided by the standard table, while 360° rotation designed into the attachment allows the surgeon to sit during surgery. The critical cords and tubes are routed through the attachment to avoid pulling and kinking. A four-bar locking mechanism allows easy attachment to standard medical railing. Finally, a straight line mechanism provides positive locking of the rotation, allowing precise positioning of the infant.

Abstract The average speed of European City traffic is less than 12 miles per hour and the vast majority of journeys are less than two miles. It seems reasonable therefore to devise an environmentally friendly vehicle with low or zero emissions to serve a market that requires safe but manoeuvrable transport with a small road footprint. Working with European colleagues in industry and academia a narrow track three-wheeled vehicle with crash protection, partial enclosure, electric drive and lightweight construction has been developed to the prototype stage. In this paper the design evolution of a tilting mechanism for this narrow track vehicle which provides locking of the tilt axis at low speed and variable damping at high speed is presented. Active and passive alternatives are discussed and a passive alternative is chosen on the basis of cost and safety. A range of actuation and speed sensing mechanisms are compared and a solution identified which is simple, low power, low cost and controllable. The system uses appropriate technology with a low maintenance requirement that is both compact and lightweight. Despite the potential for good reliability the system is designed to be fail safe; it is of paramount importance that the vehicle be allowed to tilt freely rather than become locked once the speed has risen above that required to balance. The driving style required at low speed, when the tilt axis is locked, will be different to that required at higher speeds, when the handling will be similar to that of a standard motorcycle. However the low lateral accelerations associated with low speed manoeuvres should make the change in driving style imperceptible and a degree of rear wheel steering, introduced as a result of the tilt axis, should improve mid-speed manoeuvrability. Having an estimated sale cost of $7000 the vehicle would be suitable for personal transport or a carrier of light loads in city environments.

Abstract Solar trackers make solar panels perpendicular to solar ray to enhance solar power reaping. The relative motion between Sun and Earth has two degrees of freedom. Sun travels from east to west during daytime and also moves north and south due to Earth’s tilt. However, Sun’s daily north-south move is much smaller than its east-west move. Sensor-based solar trackers make solar panels perpendicular to solar ray based on sensor information. Although the existing sensor-based solar trackers increase solar power reaping from solar panels significantly, they also consume considerable power by driving solar trackers. Sensorless solar trackers make solar panels perpendicular to solar ray based on calculated solar location. The performance of sensorless solar trackers is not affected by bad weather. This paper is on sensorless solar trackers. Single-axis solar trackers have one degree of freedom solar tracking motion. They can catch Sun’s daily east-west movement effectively. The Sun’s small north-south movement can be covered for single-axis solar trackers by monthly or seasonal adjustment of their orientations. This research is focused on single-axis sensorless solar trackers that are driven by linear actuators. The advantages of linear actuator driven solar trackers are their self-locking function and high load carrying capacity. Their challenges include limited solar panel motion range, potential interference between an oscillating solar panel and its fixed supporting ground link, and high motor power consumption for solar tracking. The research of this paper is motivated by surmounting the challenges facing sensorless single-axis linear actuator driven solar trackers. In this research, linear actuator driven solar trackers will be designed and analyzed. The models of the designed solar trackers will be developed. The kinematic and dynamic performances of the modeled solar trackers will be analyzed and simulated. The results of this research will provide some guidelines for developing linear actuator driven solar trackers.