5 research outputs found
Development of a device to simulate tooth mobility
No full textObjectives: The testing of new materials under simulation of oral conditions is essential in medicine. For simulation of fracture strength different simulation devices are used for test set-up. The results of these in vitro tests differ because there is no standardization of tooth mobility in simulation devices. The aim of this study is to develop a simulation device that depicts the tooth mobility curve as accurately as possible and creates reproducible and scalable mobility curves. Materials and methods: With the aid of published literature and with the help of dentists, average forms of tooth classes were generated. Based on these tooth data, different abutment tooth shapes and different simulation devices were designed with a CAD system and were generated with a Rapid Prototyping system. Then, for all simulation devices the displacement curves were created with a universal testing machine and compared with the tooth mobility curve. With this new information, an improved adapted simulation device was constructed. Results: A simulations device that is able to simulate the mobility curve of natural teeth with high accuracy and where mobility is reproducible and scalable was developed
Scher-Abschäl-Festigkeit von Brackets bei Anwendung selbstätzender Haftvermittler nach Lichthärtung mit einer konventionellen Halogenlampe sowie einer Hochleistungs-LED-Lampe zu jeweils zwei verschiedenen Polymerisationszeiten
No full textANALISIS PENGHEMATAN ENERGI LISTRIK PADA PJU DI RUAS JALAN LAMPER TENGAH KOTA SEMARANG DENGAN MENGGUNAKAN LED DAN PJU - TS
No full textAbstrakPenerangan Jalan Umum (PJU) merupakan salah satu fasilitas yang disediakan oleh Pemerintah Daerah untuk meningkatkan keamanan, kenyamanan para pengguna jalan, serta dapat meningkatkan estetika jalan. Konservasi energi merupakan kebijakan Pemerintah untuk menghemat energi listrik, dimana kebijakan ini harus dilaksanakan oleh Pemerintah Pusat, Pemerintah Daerah, industri, dan masyarakat. Salah satu konservasi energi yang dapat dilaksanakan oleh Pemerintah Daerah adalah dengan melaksanakan penghematan di PJU. Lampu LED adalah lampu yang mempunyai tingkat efisiensi yang tinggi, memiliki umur pemakaian yang panjang, dan dapat diaplikasikan untuk pemakaian di dalam ataupun luar ruangan. Pada penelitian ini, penulis menganalisis tingkat penghematan energi listrik yang dapat dilaksanakan oleh Pemerintah Kota Semarang jika terjadi penggantian lampu eksisting PJU di Lamper Tengah dengan menggunakan LED dan PJU ”“ TS. Penghematan energi listrik yang dapat dihasilkan dengan melaksanakan penggantian lampu eksisting dengan lampu LED di ruas Jalan Lamper Tengah sebesar 2,58 kWh/hari atau 77,4 kWh/bulan dengan penghematan tagihan listrik sebesar Rp 191.197/bulan atau setara dengan penghematan Rp 2.294.364/tahun. Penggantian 6 titik lampu PJU konvensional 40 W dengan PJU-TS dapat menghemat tagihan rekening listrik sebesar Rp 382.394/bulan atau Rp 4.588.728/tahun dengan payback periode sebesar 14 tahun.Kata kunci: konservasi energi, PJU, LEDAbstractPublic Street Lighting (PJU) is one of the facilities provided by the Regional Government to improve safety, comfort of road users, and can improve road aesthetics. Energy conservation is a Government policy to save electrical energy, where this policy must be implemented by the Central Government, Regional Government, industry, and the community. One of the energy conservation that can be implemented by local governments is to implement savings in PJU. LED lamps are lamps that have a high level of efficiency, have a long service life, and can be applied for indoor or outdoor use. In this study, the author analyzes the level of electrical energy savings that can be implemented by the Semarang City Government if there is a replacement of existing PJU lamps in Central Lamper using LEDs and Solar Light Pole. Saving electrical energy that can be generated by replacing existing lights with LED lights on Lamper Tengah street section of 2,58 kWh / day or 77,4 kWh / month with savings in electricity bills of Rp 191.197 / month or equivalent to savings of Rp 2.294.364 / year. Replacing 6 conventional 40 W PJU light points with Solar Light Pole can save electricity account bills of IDR 382,394 / month or IDR 4,588,728 / year with a payback period of 14 years.Keywords: energy conservation, PJU, LE
Does a reduction of polymerization time and bonding steps affect the bond strength of brackets?
No full textInvestigating NIR Illumination for Nighttime Bird Tracking with RGB Cameras
No full textDenne masteroppgaven har brukt en wayfaring-tilnærmingen inspirert av Steinert & Leifer i et forsøk på å utvikle en konstandseffektiv metode som bruker kommersielt tilgjengelige RGB-kameraer for å overvåke fugleaktivitet rundt havgående vindturbiner. På grunn av økt fokus rundt havvind som en del-løsning for å bekjempe klimaendringene har det oppstått en debatt rundt innvirkning de har på det biologisk mangfoldet. For å forbedre kunnskapsgrunnlaget for beslutningstagere er det nødvendig å utvikle metoder som tillater forskere å få rask og nøyaktig data om hvordan dyrelivet påvirkes. Arbeidet i denne masteroppgaven er en fortsettelse av forfatterens tidligere arbeid innen dette temaet, og undersøker autonome metoder for å skaffe kollisjonsrater mellom fugler og turbiner.
I den første konseptundersøkelsen, her referert til som en sondering, ble det undersøkt om kommersielt tilgjengelige kameraer kan oppdage fugler med det tilgjengelige bakgrunnslyset om natten. Dette ville tillatt eksisterende kamerasystemer eller rimelige kameraer å bli modifisert, og dermed fjerne behovet for andre, dyrere løsninger. Ved å fjerne det infrarøde (IR) båndpassfilteret tillates lyset utenfor det synlige spekteret å komme inn til bildebrikken i kameraet, noe som gir det bedre nattsynsegenskaper. Undersøkelser antyder på at det tilgjengelige nattlyset for seg selv ikke er tilstrekkelig, så bruken av en nær infrarød (NIR) lyskilde ble undersøkt videre.
I den andre sonderingen ble en NIR lyskilde undersøkt i kombinasjon med det modifiserte kameraet, med mål om å finne det nødvendige lysnivået. Resultatene fra eksperimenter indikerer at en 20W lyskilde med et horisontalt og vertikalt synsfelt på 40 grader sannsynligvis er tilstrekkelig for videoopptak med kort lukketid å oppdage tilstedeværelsen av fugler på korte avstander. Imidlertid ble det på grunn av usikkerheter i utstyret og metodene ikke funnet et nødvendig lysnivå. Likevel ble verdifull informasjon angående oppsettet for videre eksperimentering oppnådd. Det ansees også som usannsynlig at en enkelt lampe 20W, 40 graders FOV lampe vil være tilstrekkelig for kvaliteten som kreves for at en observasjon og gjenkjennelse skal oppnås for fugler på lengere avstander. Derfor ble det besluttet å utvikle en metode for å øke lysintensiteten.
En omfattende bruk av lamper er vurdert som uønsket, da det antas å redusere sannsynligheten for at løsningen blir implementert. Derfor ble en metode for å øke lysintensiteten til en enkelt lampe undersøkt. I den siste sonderingen ble det dermed undersøkt om en smal lampe kan belyse det ønskede området i løpet av en rimelig tidsperiode. Et forslag til design og funksjon blir skissert, hvor lysstrålen til en enkelt lampe blir fokusert for å øke strålings intensiteten. For å dekke det nødvendige området er det foreslått å sveipe lyskjeglen over det ønskede området. Videre ble det samlet begrensninger angående sikkerhet og praktisk gjennomføring som retningslinjer for videre utvikling. Et konseptbevis ble utviklet, som illustrerer at det bør være mulig å oppnå en tilstrekkelig opplyst video.
Konklusjonen er dermed at et modifiserte RGB-kameraer bør være egnet for nattovervåkning til en viss grad. Videre er løsningen presentert i den tredje sonderingen lovende, men ytterligere arbeid er nødvendig. Dette inkluderer hvordan man kan fokusere lysstrålen, hvordan den kan styres, og hvordan småskalamodeller skal utvikles. Et linsesystem, muligens kombinert med noe rotasjon av lampen selv, blir foreslått for videre undersøkelser fro å styre lyskjeglen. For småskala testoppsettet anbefales det å utvikle en passende termineringskriterium basert på sluttbrukeren for å kunne avgjøre når en løsning er tilstrekkelig. I tillegg burde småskalamodellene av fugler gjenspeile detaljene til en faktisk fugl. Til slutt bør en metode for å sammenligne kameraers følsomhet ovenfor NIR lys bli utviklet, slik at det blir enklere for bedrifter og andre som kan være interessert i å utnytte løsningen å finne passende kameraer.This thesis has used the wayfaring approach in an attempt to develop a method that uses commercially available RGB cameras for monitoring bird activity around offshore wind turbines at a low cost. Due to the increased focus on offshore wind turbines as a way of battling rapid climate change, the potential loss of biodiversity caused by renewable energies has been a source of debate. To increase the knowledge about the impact, it is necessary to develop methods allowing scientists to get fast and accurate data on how wildlife is influenced to gain better grounds for decision-makers. The work of this thesis is a continuation of the previous work of the author, investigating autonomous methods for obtaining collision rates between birds and turbines.
In the first concept-investigating process, referred to as a probe, it was investigated if commercially available cameras can detect birds with the available ambient light at night. This would allow existing camera systems or cheap cameras to be modified and remove the need for other, more expensive solutions. By removing the infrared (IR) cutoff filter, the light outside of the visible spectrum is allowed into the image sensor of the camera, consequently giving it better night vision capabilities. However, the ambient night light by itself is considered insufficient, and the use of a near infrared (NIR) light source was investigated.
In the second probe, a NIR light source in combination with the modified camera was investigated, trying to find the minimum required amount of light. Results from experiments indicated that a 20W light source with a horizontal and vertical FOV of 40 deg is likely sufficient for videos with a high frame rate to detect the presence of birds at short distances. However, due to uncertainties in the equipment and methodology, no minimum value for the required illumination was obtained. Yet, valuable information regarding the setup of further experiments was obtained. Further, is considered likely that a single lamp is insufficient for confident detection and recognition of birds at long distances. Thus, it was decided to develop a method for increasing the light intensity.
Extensive use of lamps was undesirable, as it is assumed to reduce the likelihood of implementation. Therefore, a method for increasing the light intensity by focusing the lamp is investigated. Thus, the last probe investigates whether a single narrow lamp can illuminate the desired area in a reasonable amount of time. A proposal to design and function is outlined, with a narrowed light beam to increase the radiant intensity of a single lamp and swipe it over the desired area. Further, limitations regarding safety and practicality were gathered to function as guidelines for further development. A proof of concept was developed and presented, illustrating that a sufficiently illuminated video stream should be possible to obtain.
It is thus concluded that modified RGB cameras should be suitable for some degree of nighttime surveillance if a NIR source is present. Further, the solution presented in the third probe is promising, but further work is needed. This includes how to focus the required light beam, how it can be steered, and how small-scale models should be developed. A lens system, possibly in combination with some rotation of the lamp itself, is suggested for further investigations. For the small-scale test setup, it is recommended that a proper termination criterion is developed based on the end-user and that the small-scale bird models should mimic the details of an actual bird. At last, a method for comparing the NIR sensitivity of the camera should be developed to make it easier for companies and others interested in utilizing the solution to find suitable cameras
