872 resultados para mechanical device


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This report describes a simple, inexpensive and highly effective instructional model based on the use of a tablet device to enable the real-time projection of the instructor's digitally handwritten annotations to teach chemistry in undergraduate courses. The projection of digital handwriting allows the instructor to build, present and adapt the class contents in a dynamic fashion and to save anything that is annotated or displayed on the screen for subsequent sharing with students after each session. This method avoids the loss of continuity and information that often occurs when instructors switch between electronic slides and white/chalk board during lessons. Students acknowledged that this methodology allows them to follow the instructor's cognitive process and the progressive development of contents during lectures as the most valuable aspect of the implemented instructional model.

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AbstractA device comprising a lab-made chamber with mechanical stirring and computer-controlled solenoid valves is proposed for the mechanization of liquid-liquid extractions. The performance was demonstrated by the extraction of ethanol from biodiesel as a model of the extraction of analytes from organic immiscible samples to an aqueous medium. The volumes of the sample and extractant were precisely defined by the flow-rates and switching times of the valves, while the mechanic stirring increased interaction between the phases. Stirring was stopped for phase separation, and a precise time-control also allowed a successful phase separation (i.e., the absence of the organic phase in the aqueous extract). In the model system, a linear response between the analytical response and the number of extractions was observed, indicating the potential for analyte preconcentration in the extract. The efficiency and reproducibility of the extractions were demonstrated by recoveries of ethanol spiked to biodiesel samples within 96% and 100% with coefficients of variation lower than 3.0%.

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Background: Pacemaker implantation (PMI) may predispose to venous thromboembolism (VTE) and obstruction (VO). This prospective study aimed at quantifying changes in venous calibers, and at determining the incidence of symptomatic and asymptomatic VTE/VO after PMI. Further goals included an assessment of the role of transesophageal echocardiography (TEE) in the diagnosis of lead-related central venous thrombi (CVT), and determination of predictors for VTE/VO. Methods: 150 (mean age 67; 61% male) consecutive patients with first PMI were enrolled and followed for 6 months. Contrast venography was performed at baseline and 6 months after PMI to measure venous diameters, and to detect stenosis, total occlusions and thrombi. TEE was conducted in 66 patients. Based on clinical suspicion, work-up for pulmonary embolism (PE) or acute deep vein thrombosis (DVT) were performed as needed. A total of 50 cases underwent longer-term (mean 2.4 years) follow-up venography. All cases with VTE/VO during the initial 6 months, and their matched controls, were selected for a case-control study focused on possible predictive role of laboratory and patient-related factors for the development of VTE/VO. Results: 10 (7 %) patients were found to have baseline venous abnormalities (e.g. 8 obstructions). Mean venous diameters diminished significantly during the first 6 months, but no further reduction occurred in late follow-up. New VO was discovered in 19 patients (14 %; 14 stenosis, 5 total occlusions; all asymptomatic). Small non-obstructive thrombi were found in 20/140 (14 %) 6-month venograms. TEE at 6 months disclosed CVT in 6 (9 %) patients. One (0.7 %) patient had acute symptomatic upper-extremity DVT, and PE was discovered in 5/150 (3.3 %) patients during the first 6 months with no further cases thereafter. At 6 months, the total number of cases with VTE/VO amounted to 47 (31.3 %). Additionally, the later 2-year venograms (n=50) disclosed 4 (8 %) total occlusions and 1 (2 %) stenosis. In the case-control study, no parameter was predictive of venous end-points as a single variable, but there appeared to be significant clustering of traditional VTE risk-factors among the cases. Laboratory parameters showed a definite acute hypercoagulative state induced by PMI, but its degree did not predict subsequent development of VTE/VO. Conclusions: This study shows that VTE/VO is relatively common after PMI with an overall incidence of at least 30 %. Although the majority of the lesions are asymptomatic and clinically benign, cases of PE were also encountered, and totally occluded veins may hamper future upgrading or replacement of pacing system. Venous complications seem difficult to prognosticate as firm predictors were not identified from a wide range of parameters analyzed in this study, although clustering of classic VTE risk factors may be a predisposing factor. Parameters related to implantation procedure or pacing systems and the severity of implantation-induced trauma did not emerge as predictors.

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The subject being analyzed of this Master’s Thesis is a development of a service that is used to define a current location of a mobile device. The service utilized data that is obtained from own GPS receiver in some possible cases and as well data from mobile devices which can be afforded for the current environment for acquisition of more precise position of the device. The computation environment is based on context of a mobile device. The service is implemented as an application for communicator series Nokia N8XX. The Master’s Thesis presents theoretical concept of the method and its practical implementation, architecture of the application, requirements and describes a process of its functionality. Also users’ work with application is presented and recommendations for possible future improvements are made.

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Diplomityö tehtiin Lappeenrannan teknillisen yliopiston konetekniikan laitokselle. Diplomityö on osa teknillisen yliopiston biomekaanista tutkimusta, jonka tarkoituksena on mallintaa ihmisen tuki- ja liikuntaelimistön toimintaa. Työssä pyrittiin selvittämään, voitaisiinko sääriluuhun kohdistetun mekaanisen herätteen aiheuttamaa värähtelyvastetta analysoimalla saada tietoa luun ominaistaajuuksista ja lujuudesta. Tietoa voitaisiin käyttää esimerkiksi ostoporoosiriskin arvioinnissa sekä ihmiskehon osien toimintaa kuvaavien simulointimallien verifioinnissa. Mittauslaitteistona käytettiin Brüel & Kjær-moodianalyysilaitteistoa. Laitteistokokonaisuuteen kuuluivat herätevasara, elektromagneettinen täristin, voima-anturi, kaksi kiihtyvyysmitta-anturia sekä PulseLab 2.0 –ohjelmistolla varustettu PC-laitteisto. Tulosten jatkoanalyysi suoritettiin MathWorks yhtiön MatLab v 4.0 -ohjelmistolla. Työssä esitellyn mittaustavan ja -laitteiston todettiin soveltuvan sääriluun värähtelyvasteen mittaamiseen. Mittaustulokset eri mittauskertojen välillä samalla henkilöllä ovat yhtenevät. Tutkimuksen tulosten perusteella ei voida osoittaa luun värähtelyvasteen ja lujuuden välistä suoraa korrelaatiota.

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Recently most of the mobile phone manufacturer companies started to pay extra attention to their websites. This research investigates the sources of value creation on the mobile phone manufacturers’ website and the affect visiting the manufacturers’ website has on brand loyalty and brand satisfaction. The results show a correlation between positive website usage experience, brand loyalty and brand satisfaction. Moreover there is a relation between Novelty, Efficiency, Lock-in and the perceived usefulness the manufacturers’ website has on the mobile phone device. And finally the main reason behind Finnish student’s mobile phone brand loyalty is its country of origin.

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Segmentointi on perinteisesti ollut erityisesti kuluttajamarkkinoinnin työkalu, mutta siirtymä tuotteista palveluihin on lisännyt segmentointitarvetta myös teollisilla markkinoilla. Tämän tutkimuksen tavoite on löytää selkeästi toisistaan erottuvia asiakasryhmiä suomalaisen liikkeenjohdon konsultointiyritys Synocus Groupin tarjoaman case-materiaalin pohjalta. K-means-klusteroinnin avulla löydetään kolme potentiaalista markkinasegmenttiä perustuen siihen, mitkä tarjoamaelementit 105 valikoitua suomalaisen kone- ja metallituoteteollisuuden asiakasta ovat maininneet tärkeimmiksi. Ensimmäinen klusteri on hintatietoiset asiakkaat, jotka laskevat yksikkökohtaisia hintoja. Toinen klusteri koostuu huolto-orientoituneista asiakkaista, jotka laskevat tuntikustannuksia ja maksimoivat konekannan käyttötunteja. Tälle kohderyhmälle kannattaisi ehkä markkinoida teknisiä palveluja ja huoltosopimuksia. Kolmas klusteri on tuottavuussuuntautuneet asiakkaat, jotka ovat kiinnostuneita suorituskyvyn kehittämisestä ja laskevat tonnikohtaisia kustannuksia. He tavoittelevat alempia kokonaiskustannuksia lisääntyneen suorituskyvyn, pidemmän käyttöiän ja alempien huoltokustannusten kautta.

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In general, the traditional Physics courses needs examples of the aplications of the Physics concepts in other areas such as Chemistry and Biology. This lacks tend to demotivate Chemistry and Biology students regarding to deal with Physical concepts developed in classroom. In this work, the analogy among mechanic and electric oscillators is investigated to be applied in Chemistry and Biology areas, showing to be valuable due to its aplication in techniques that aims to measure mass variation with high precision. This measure could be made in a direct or indirect way. These techniques are known as electrogravimetric techniques and they are important in biosensor aplications. Thus, this paper explores the electromechanic analogy in an interdisciplinary way involving areas like Physics, Chemistry and Biology. Based on this analogy, it is proposed an experiment that can be applied in different ways, i.e. by an basic approach or more deeper, depending on the students specific formation, in other words, Physics, Chemistry or Biology.

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Diplomityön tavoitteena oli kehittää Wipak Oy:n valmistamille sterilointipakkauksille tulevaisuuden pakkauskonsepti. Sterilointipakkaukset luokitellaan lääkelaitedirektiivin mukaan lisätarvikkeiksi luokan 1 lääkelaitteille, ja tämä näkökulma oli vahvasti mukana konseptin kehityksessä. Lähtökohtana pakkauskonseptin suunnittelulle oli tuotteiden arvoketjussa, eli pakata tuotteet siten että pakkausten avulla voidaan tuottaa lisäarvoa arvoketjun toimijoille. Tavoitteena oli parantaa pakkausten viestintää, toimivuutta/tehokkuutta toimitusketjussa sekä vahvistaa brändin imagoa myynti- ja kuljetuspakkauksen avulla. Lääkinnälliset laitteet ja tarvikkeet ovat lainsäädännön ja normien avulla tarkasti säädeltyjä. Näiden normien vaatimukset asettavat perusteet myynti- ja kuljetuspakkausten kehittämiselle. Tämän lisäksi suunnittelussa on huomioitu asiakkaiden toiveet ja kehitystarpeet. Kirjallisuusosuudessa on keskitytty lääkinnällisten laitteiden pakkausyksiköiden toimintoihin sekä niiden kehitysnäkymiin. Pääpaino on ollut pakkausmerkintöjen ja jäljitettävyyden kehittämisellä, koska tietojen automaattisen tunnistuksen hyödyntäminen lääkintälaitteiden pakkausten arvoketjussa on kasvava trendi. Manuaalisesti tehtävät tuotevirtojen kirjaukset ketjun eri toimijoiden osalta lisäävät riskejä jäljitettävyyden kannalta ja aiheuttavat lisätyötä ja – kustannuksia ketjun kaikille osapuolille. Ehdotus uudesta pakkauskonseptista on kehitetty näiden tietojen pohjalta. Ehdotuksessa on huomioitu lainsäädännöstä ja ketjun toimijoilta tulevat tarpeet, sekä alan tulevaisuuden kehitysnäkymät. Ehdotetun pakkauskonseptin avulla saadaan lisättyä myynti- ja kuljetuspakkausten tehokkuutta, parannettua jäljitettävyyttä ja helpotettu arvoketjun alavirran toimijoiden työtä lisäämällä erillinen sisäpakkaus myyntiyksikön sisälle. Työssä on lisäksi selvitetty pakkauskonseptin kustannusvaikutukset tuotteiden hintaan. Lopussa on ehdotettu jatkotoimenpiteet suunnitelman implementoimisesta käytäntöön.

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This thesis is done as a part of project called FuncMama that is a project between Technical Research Centre of Finland (VTT), Oulu University (OY), Lappeenranta University of Technology (LUT) and Finnish industrial partners. Main goal of the project is to manufacture electric and mechanical components from mixed materials using laser sintering. Aim of this study was to create laser sintered pieces from ceramic material and monitor the sintering event by using spectrometer. Spectrometer is a device which is capable to record intensity of different wavelengths in relation with time. In this study the monitoring of laser sintering was captured with the equipment which consists of Ocean Optics spectrometer, optical fiber and optical lens (detector head). Light from the sintering process hit first to the lens system which guides the light in to the optical fibre. Optical fibre transmits the light from the sintering process to the spectrometer where wavelengths intensity level information is detected. The optical lens of the spectrometer was rigidly set and did not move along with the laser beam. Data which was collected with spectrometer from the laser sintering process was converted with Excel spreadsheet program for result’s evaluation. Laser equipment used was IPG Photonics pulse fibre laser. Laser parameters were kept mainly constant during experimental part and only sintering speed was changed. That way it was possible to find differences in the monitoring results without fear of too many parameters mixing together and affecting to the conclusions. Parts which were sintered had one layer and size of 5 x 5 mm. Material was CT2000 – tape manufactured by Heraeus which was later on post processed to powder. Monitoring of different sintering speeds was tested by using CT2000 reference powder. Moreover tests how different materials effect to the process monitoring were done by adding foreign powder Du Pont 951 which had suffered in re-grinding and which was more reactive than CT2000. By adding foreign material it simulates situation where two materials are accidently mixed together and it was studied if that can be seen with the spectrometer. It was concluded in this study that with the spectrometer it is possible to detect changes between different laser sintering speeds. When the sintering speed is lowered the intensity level of light is higher from the process. This is a result of higher temperature at the sintering spot and that can be noticed with the spectrometer. That indicates it could be possible to use spectrometer as a tool for process observation and support the idea of having system that can help setting up the process parameter window. Also important conclusion was how well the adding of foreign material could be seen with the spectrometer. When second material was added a significant intensity level raise could be noticed in that part where foreign material was mixed. That indicates it is possible to see if there are any variations in the material or if there are more materials mixed together. Spectrometric monitoring of laser sintering could be useful tool for process window observation and temperature controlling of the sintering process. For example if the process window for specific material is experimentally determined to get wanted properties and satisfying sintering speed. It is possible if the data is constantly recorded that the results can show faults in the part texture between layers. Changes between the monitoring data and the experimentally determined values can then indicate changes in the material being generated by material faults or by wrong process parameters. The results of this study show that spectrometer could be one possible tool for monitoring. But to get in that point where this all can be made possible much more researching is needed.

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Työssä tutkittiin polymeerisen ultrasuodatuskalvon modifiointimahdollisuuksia prosessiolosuhteita muuttamalla. Kalvon modifioimisella pyritään sen suodatusominaisuuksien muuttumiseen, joka voi lisätä kalvon käyttökohteita ja parantaa kalvon soveltuvuutta tiettyjen yhdisteiden suodatukseen. Hydrofiilisiä, tiukkoja polymeerisiä ultrasuodatuskalvoja on kaupallisesti saatavilla vähän, joten työssä tutkittiin niiden valmistusta modifioimalla markkinoilla olevaa, löysempää, hydrofiilistä, polymeeristä ultrasuodatuskalvoa. Ultrasuodatuskalvo modifioitiin paineen, lämpötilan ja emäksen avulla. Modifioinnin aiheuttamat muutokset voidaan jakaa pysyviin, osittain palautuviin tai palautuviin muutoksiin. Kalvon rakenteen muuttuessa pysyvästi voidaan kalvo modifioida ennen suodatuksen aloittamista. Tällöin modifioinnissa käytetyt olosuhteet eivät vaikuta suodatukseen kuten muissa tapauksissa. Modifioinnin vaikutusta kalvoon voidaan analysoida eri menetelmillä. Näitä ovat esimerkiksi elektronimikroskopia ja kalvon vuon tai retention analysointi. Mikroskooppikuvia ei voida ottaa suodatuksen aikana, vaan kalvosta saada tietoa ainoastaan alku- ja lopputilanteissa suodatusolosuhteista poistettuna. Vuon ja retention avulla saadaan reaaliaikaista tietoa modifioidun kalvon suodatuskapasiteetin ja erotuskyvyn muutoksista. Työssä modifioinnin vaikutusta seurattiin vuo- ja retentiomittausten avulla ja kalvon rakenteessa tapahtuvia muutoksia tutkittiin pyyhkäisyelektronimikroskooppikuvien ja mikrometrimittausten avulla. Korkeampaa painetta tai lämpötilaa käytettäessä havaittiin vuon alenevan modifioitaessa enemmän kuin matalammissa paineissa tai lämpötiloissa. Korkeampi puristuslämpötila kasvatti myös retentiota. Modifiointiolosuhteiden ollessa emäksisiä aleni permeabiliteetti neutraaleissa olosuhteissa tehtyä puristusta enemmän. Myös retentio aleni emäksen avulla tehdyssä modifioinnissa. Kalvon rakenteessa tapahtuneiden muutosten palautuminen riippui modifiointilämpötilasta, korkeassa lämpötilassa modifioidussa kalvossa palautumista ei tapahtunut. Modifioinnin aiheuttamat kalvojen paksuuden muutokset tukivat retentio- ja vuomittauksia. Pyyhkäisyelektronimikroskooppikuvista voitiin havaita kalvon huokosrakenteen puristuneen modifioinnin aikana.

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The 'Niagara Rosada' grape is the main Brazilian table grape belonging to the Labrusca family. It develops medium, cylindrical and compact bunches with berries presenting a pinkish skin and a foxy flavor that is valued in the Brazilian market. These berries are tender and have a pedicel-berry connection provided by the vascular bundles and surrounding skin. This cultivar is very susceptible to berry drop mainly caused by vibration and senescence. The objective of this study was to evaluate the temporal mechanical behavior of the pedicel-berry detachment, using resistance indexes extracted from traction force-deformation curves. Test results showed two different detachment types. In the first one, which exhibited higher average resistance, a considerable portion of the vascular bundle came out attached to the pedicel and in the second type; the vascular bundle was retained inside the berry. The proposed indexes based on maximum detachment force, force at 0.2; 0.5; 1.0 and 1.2 mm, and maximum force to corresponding deformation ratio did not discriminate the senescence of the berry.

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Due to the importance of the environment on animal production and thus environmental control, the study aims to build a system for monitoring and control the meteorological variables, temperature and relative humidity, low cost, which can be associated with an evaporative cooling system (ECS). The system development included all the stages of assembly, test and laboratory calibration, and later the validation of the equipment carried in the field. The validation step showed results which allowed concluding that the system can be safely used in the monitoring of these variables. The controller was efficient in management of the microclimate in the waiting corral and allowed the maintenance of the air temperature within the comfort range for dairy cattle in pre-milking with averaged 25.09 ºC during the afternoon. The equipment showed the lower cost (R$ 325.76) when compared to other middle market (R$ 450.00).