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245 Uppsatser om Acoustic signals - Sida 5 av 17

Styrsystem : För en forskningsutrustning

The division of Engineering Materials at Linköping University, department of Management and Engineering, conducted a research project concerning Fatigue life of thermal barrier coatings during 2009. During this project equipment to provoke these fatigue failure by rapidly heating and cooling test subjects in cycles, was ordered.Design and manufacturing of the equipment was handled internally at LIU.The equipment was built using a furnace that is lowered and raised over the table where the test subject is placed. To keep the temperature of the furnace a lid slides in place to close the downward facing opening of the furnace when it is in the raised position. On this door there is nozzle that is used to cooling of the test subject by air.To make sure that the equipment can work independently you need an automation controller that can evaluate if movement can occur without danger of collisions. The control system also needs to monitor that all elements are performed according to plan.This degree project is based on a modular system from OPTO 22 and includes the configuration of a PLC that will be supplied with logic and a user interface.The degree project resulted in a graphic interface in which a user can set desired values for different parameters and get information about current values for them.

Optimering av informationsinsamlingvid prototyptillverkning

This report discusses a method to detect divers in harbour environments usingpassive acoustic detection. The goal was to achieve as high detection as possiblewithout having too high false alarm rate. A short execution time was also desirable.By using the characteristic of an inhalation a band-pass filter was applied to the signalto improve the signal to noise ratio. After the filtering an energy estimation of thesignal was made. This energy estimation was later used in a frequency analysis, whichcould tell us if there were enough energy in the frequencies that correspond to adivers breathing frequency.

Ljudreducering av värmepump

This degree project handles acoustic measurements of the heat pump EcoAir 107, made by Enertech CTC AB. The sound from the three sound sources of the heat pump, fan, compressor and four way valve, have been measured to find out how they affect the total sound level of the product.Measures to attenuate the sound level have been developed and tested. By comparing these with the sound of the heat pump, in its original state, we have found out the measures which have best effects.The best attenuating measures came to be: taped openings and holes around the compressor space, isolating the top and the bottom of the whole construction, support of the fan bottom part and shielding of the sound source with a screen at a distance of 110 mmThese measures have been tested together and an average attenuation of the total sound level with 3,9 dB have been accomplished. In the front of the fan where the continuous sound is the strongest, the attenuation was 4,7 dB.This project is meant to be used as a guide by Enertech CTC AB:s during their future developing process..

Lågoffsetkomparator

Detecting small signals with a comparator demands that the total voltage offset is lower than the actual signal. The total offset includes the voltage offset in the comparator and the voltage offset that is created by the offset currents that flows thru the load at the comparators input. The goal with this comparator that has been developed has been that it will have a total voltage offset at maximum 500 uV. The comparator does not need to be extremely fast or does not need to operate in a big frequency area. To have all the flexibility that is needed a full custom technique is used.

Arga röster ökar muskelanspänningen

Syftet var att undersöka om exponering inför emotionella röster påverkar muskelanspänning och hjärtats slagfrekvens samt om det finns en samvariation mellan storlek eller längd på muskelanspänning vid aversiv emotionell input och grad av alexitymi. 24 studenter lyssnade på arga, glada och neutrala röster samtidigt som muskelanspänning mättes med EMG och hjärtats slagfrekvens med EKG. Grad av alexitymi mättes med Toronto Alexithymia Scale 20. Resultaten visade att arg eller glad röststimuli gav större muskelanspänningen än neutralröststimuli. Ingen skillnad i muskelanspänning fanns mellan arg eller glad röst.

Analys av arbetsmiljö vid kokarpåsvetsning samt förslag till förbättringar.

Denna rapport är ett inledande steg mot att förbättra arbetsmiljön för svetsare vid påsvetsning med Uddcomb Metoden i massakokare. Syftet med rapporten är att analysera problemet med värme och dålig luft samt förklara hur och varför problemet uppstår. I arbetet ingår även att ta fram olika lösningar för att slutligen hitta ett komplett system för ventilation och kylning. Den föreslagna lösningen består av ett integrerat kylsystem och ett koncept med mindre fläktar, kallade torpeder, som monteras på arbetsplanen vilka driver ut varm och smutsig luft snabbare ur kokaren. Den föreslagna lösningen utreds även ur ett ekonomiskt perspektiv.

Hydroakustisk kommunikation med bandspridningsteknik

This thesis investigates techniques for stealth hydroacoustic communication using spread spectrum. The Swedish naval defense organisations have a vision that all their units should be able to communicate with each other, even between underwater vehicles. But the properties of water makes it a complex channel to use for wireless communications. Radiomagnetic waves have very limited range in water, therefore acoustic waves are used. In this report the basics of wireless communication systems are described including source coding, channel coding, modulation techniques as well as different techniques for spread spectrum.

Sound - Sense - Space: Might sound affect our experience of a room?

Syfte: Rapportens syfte är att kartlägga om upplevelsen av ett rum kan förändras beroende på om och vilka ljud som spelas upp i rummet. Metod: I samband med en ljudinstallation på Plattan vid Malmö Högskola har rörelsemönster och beteende för Plattans besökare observerats. Dessutom har flera besökare besvarat en enkät. Resultat: Inga eventuella förändringar i rörelsemönstret eller beteendet för Plattans besökare kan ses som en konsekvens av ljudinstallationen. Det finns inte heller någon skillnad i enkätsvaren beroende på installationen. Slutsats: Resultatet ses som en konsekvens av bristfälliga forskningsmetoder. I rapportens slutsats bildas hypotesen att en installerad ljuddesign inte är en tillräcklig åtgärd i den undersökta typen av miljö.

Ombyggnad av lägenheter i ett 1950-tals flerbostadshus till kontorsbyggnad

The report aim to increase awareness of factors that have a major role whenremodelling an apartment building from the 1950s to offices.The thesis can be used for future projects when remodelling apartments to offices.The report can provide ideas and inspirations on how this can be done in aneffective way, ie . A way that does not require rebuilding the supporting structure,but only non bearing walls. The thesis also gives insight on the parts that will needto be supplemented from Boverket?s requirements in terms of accessibility,acoustic and fire requirements.The methods used in this thesis are literature studies, case study and sketch work.In the literature studies, the primary sources were Boverkets byggregler BBR, andArbetsmiljöverkets föreskrift AFS 2009:2 but other literature were also used. Theprimary items were chosen from the literature studies and they were furtheranalysed in the sketch work.

Perceptuell identifiering av musikgenre

This is a study in the field of Music Information Retrieval (MIR) concerning classification of musicgenre. The study uses a music listening experiment and machine learning methods to determinewhether or not the drum sounds from different songs contain sufficient information to classifygenre.MIR methods are used to extract data from the audio signals. The data is used together with theclassification results of the listening experiment to train different machine learning algorithms toclassify the songs in different genres.The results indicate that using only drum sounds for genre classifications works well, both forlisteners and for machine learning methods..

Reaktionskrafter i dragarmarna på en traktors trepunktslyft : Teori och praktik

Tractors of today come equipped with a CAN-system. A CAN-system sends information from sensors to electronic control units who process the signals. The sensors measure several interesting parameters such as force, pressure and speed for various components of the tractor. This thesis discuss a force sensor which is placed in the pivot of the tractors three point linkage, the sensor measure the horizontal reaction force from the load that the tractor is exposed to. Signals from this sensor can be used to measure the force from any implement that the tractor is exposed to during an operation.

Talar kvinnor och män samma språk? : En intervjuundersökning av män och kvinnors vardagsspråk i Halmstad

The purpose of this study is to determine if and how male or female everyday languagesdiffer. The study is based on ten interviews with five men and five women living inHalmstad, who are between the ages of 22-29. The interview results were analyzed andcompared with previous research on the subject. The result shows that there is adifference between the male and female informants use of language. Women laughing,using italics, hedges, the word så ?so? and response signals to a greater degree than men.The reason may be that men and women basically use different conversation styleswhen they communicate, that men prefer a public speech, intended to provideinformation and knowledge.

Säkerhetsbrytare för Gräsklippare

This thesis describes teh solution of two problems regarding safety on powered lawnmowers; protectning the users from injury when using the lawnmower in slopes, and when cleaning the cutting blade.The task was carried out through initial studies on a representative lawnmower. A generation of ideas followed with an evaluation to select the best solution. The winning concept was further developed to reach acceptable performance. The word resulted in a functioning prototype utilising an original way of detecting inclinations without incorrect signals. It c an serve as a platform for further development into a product.The work gives insightful experience of solving real-world problems, and especially to deal with situations where several variables and their effects are unknownPlease note that several parts of the work are confidential, and have therefore been removed from the thesis..

Mobil förvaringslösning för barn och vuxna

Databases are an easy way of storing information kept together and accessible and can save time by finding the information easier. Cochleaimplant could be seen as a form of advanced hearing aid, this product consists of two parts, an external part that recieves sound and sends signals to the internal part through electromagnetism. The internal part is the implant itself and is surgically placed in to the cochlea. Örebro University hospital has just started working within the field of Cochleaimplants and are therefore in need of a database to store patient related information.The database problem was solved using Microsoft Access 2003 combined with the built-in support for Visual Basic, which is a sort of programming language. The result of the thesis work was a fully functioning database according to the given specification and is now being used at Örebro University hospital..

Normering av nasaleringsvärden uppmätta med nasometer hos barn i fyra- till femårsåldern i Linköping

The Nasometer is a non-invasive acoustic measuring instrument that quantifies the ratio ofnasal resonance in speech. It can be used as a complement to perceptual judgment of speech impediments, for example, in patients with cleft palate and velopharyngeal insufficiency. Inorder to determine if a nasalance score is abnormal, it must be compared to norm data. The main purpose of the study was to collect reference nasalance scores in children between fourand five years of age in Linköping. An additional objective was to compare the results tonorm data collected in Umeå.

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