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933 Uppsatser om Vibration and acoustic engineering - Sida 1 av 63

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.

Utvärdering av vibrationer inom vattenkrafts normer

The International Organization for Standardization (ISO) proposes vibration standards for the evaluation for machine damage due to vibration in rotational machines, where some vibration parameters are given to measure the vibrationgrade. This work evaluates the relevance of the vibration standards in hydro plants that are proposed by the ISO, and also investigates if there are methods used in other countries could have greater importance. Through statistical analysis of collected data we got a better understanding of relation among different vibration parameters, and also the importance of correct choice of the parameters for the evaluation of vibration. We have found that the vibration standards available today in hydro plants are not reliable for the judgment of vibration?s grade.

Tuftade ljudabsorbenter ? väggpaneler för rumsliga och akustiska egenskaper

It is a well-known fact that textiles and carpets have benign sound-absorbing properties. It is desirable to have quantified values of these properties ? especially for architects and interior designers. They often need to be able to giveaccount for the acoustic properties of their designs at a relatively early stage and sometimes have strict acoustic classifications imposed upon them by their contractor. A product with documented acoustic properties would aid when prescribing interior elements.The purpose of this thesis is to develop a wall-mounted panel in hand-tufted material ? aesthetically pleasing and versatile but also having documented and quantified acoustic properties.

Perception of human acoustic communication in the domestic dog (Canis familiaris)

For most dog owners today it is natural to use acoustic stimuli such as talking to communicate with their pets. Words are used both to ask the dogs to perform tricks, as well as to hold ?conversations? with the dog. This literature review looks at how dogs perceive human acoustical communication and how this can influence the behaviour of the dog. This information could be used e.g.

Går det att mäta blodtryck med fotopletysmografi och bioakustisk sensor i kombination?

The aim of the work was to investigate the possibility to combine information from PPG and bio-acoustic technology to extract information that is related to the blood pressure. The measurements have been carried out with several different configurations. First the relation between arterial sounds and the PPG-signal was studied. After those measurements with both PPG and the bio- acoustic technique was concluded on people in different positions and after riding a bike. The goal was to vary the blood pressure.

Akustisk mätning av U-värde

This pre-study investigates the possibility of U-value measurements through an acoustic method. A hypothesis about an acoustic model built on acoustic theories combined with U-value theories is presented to answer the questions: ? Can U-value theory be combined with acoustic theories? ? Can the coefficient of heat be affirmed trough an acoustic measurement? The idea for this dissertation begun with a logical idea in mathematical similarity, between the coefficient of heat transmission units and sound intensity units. The U-value theory is based on assumptions such as initial resistance for inner walls and initial resistance for outer walls. The resistance in the material is interpreted through sound intensity theory. The argument is built upon mass law theory, which means if the frequency or thickness of the material layer doubles it implies an increase of sound reduction by 6 dB.

HAVS ombord - en studie av hand- och armvibrationssyndrom och dess förebyggande åtgärder

On board ships different type of maintenance activities take place. Some of those require working with vibrating handheld tools. Traditionally there is a high awareness of the risks with different type of duties such as protecting the skin from oil or other chemicals, the eyes from splashes and hearing from high noise levels. The experience we have from our time as on-board cadets are that there is less information about vibration hazards available compared to the information concerning other hazards on board.There are threshold values that workers, by law, are not allowed to exceed when working with handheld vibrating tools. The purpose of this study is to investigate how common the use of this type of equipment that can cause damage by vibrations, to the hands and arm amongst the deck crew, and if the crew informed about the risks involved.

Vibrationsdämpning av värmepump

Thermia Värme AB is one of the market leading manufactures of heat pumps. In order tomaintain this position, the company wants to improve the vibration characteristics of theirproducts. The aim of this thesis is to develop product design changes that lead to a reductionof vibrations in the heat pump Thermia Diplomat 8.The main cause for vibrations in the system is flow pulsation and mechanical forces inducedby the scroll compressor. Vibration is transmitted through the compressor piping and receivedby the heat exchangers, from where it is further transmitted to the connection points for theradiator and heat source circuits.A number of design changes in order to improve the vibration characteristics have beenevaluated through calculations and practical experiments. The changes have included thecompressor and heat exchanger mountings, the compressor suction and discharge line pipingand also pulsation dampening.The results of the experiments show that the vibration levels in the connections for the heatingand brine circuits can be decreased strikingly through changes in suction and discharge linepiping.

Sjukgymnasters syn på en ny behandlingsmetod med vibrationsträning som exempel: en kvalitativ studie

The aim of the study has been to investigate physiotherapists? view on a new method of treatment in physiotherapy. In this case we have studied Whole Body Vibration training as an example of a new method of treatment. Semistructured interviews were performed with five physiotherapists. The study was carried out as a qualitative content analysis study.

Kunskapsbaserat datorstöd för skadeprevention i arbetsmiljö ? En utvärderingsstudie

Information about vibration injuries as a preventive measure is beneficial to society as well as the individual. As early as after a few years work with machines that vibrate can cause young sensitive persons to develop vibration injuries.An evaluation has been done on a web page with focus on information about work related vibration injuries. As a part of the evaluation a user observation and interview study was performed with workers who worked in different occupations. The workers all used machine that vibrate as part of the work. A total of eleven workers participated in the study.

Akustiskt åtgärdsprojekt av en rockmusikklubb där live-musik spelas. Vad kan en audionom bidra med?

Introduction: The number of hearing impairments in Sweden is increasing. The largest increase is seen in ages 25-44. There are reasons to believe that these impairments are noise induced. Leisure time noise is not controlled in the same manner that industrial noise is. An ongoing conflict between city council officials and rock club owners, musicians and music event organizers about sound levels at smaller live music clubs exceeding the national sound level restrictions created the need for an acoustic intervention project.

Social Engineering : En studie om medvetenhet och förebyggande åtgärder mot Social Engineering på svenska organisationer 

Abstrakt Social Engineering är konsten att manipulera människor, för att på så sätt vinna deras förtroende. Med hjälp av detta förtroende kan attackeraren sedan kringgå säkerhetssystem och få tillgång till organisationers information. Vi har i denna uppsats genomfört elva intervjuer på tre stora organisationer med både IT-chefer och övrig personal. Med dessa intervjuer har vi sedan försökt få en bild av hur medvetenheten ser ut samt vilka åtgärder organisationerna tar för att förhindra Social Engineering. Med denna uppsats vill vi belysa den ovisshet som råder kring Social Engineering, men även farorna och hur effektiv en attack av denna typ kan vara.

Vibrationsträning vid knäledsartros

In cooperation with Hälsoteamet Halmstad a pilot study was made to see if whole body vibration exercise has any effect on muscle strength, movement and experience of pain in people with knee osteoarthritis. Today whole body vibration exercise is a revolutionary exercise method that needs more studies to show the positive and negative effects. Osteoarthritis is a degenerative disease where more cartilage is destroyed than replaced. The most common symptoms are pain, stiffness, restricted movement, muscularly atrophy, tenderness and instability. The cartilage needs pressure to rebuild, it is therefore important that the patient exercise.

En analys av steg och konsekvenser vid införande av MVC

Abstract The purpose of this essay is to find difficulties and risks in the re-engineering process when restructuring to Model-View-Controller (MVC). A thoroughly theory study has been conducted to be able to understand the important steps in the re-engineering process. The methods and concepts of this essay are re-engineering, UML, system development life cycle, design patterns and MVC. The science approach used is design science where the artifact being developed are a set of models.In the analysis phase of the process the system is analyzed. The result of the analysis is notes of difficulties found and models showing the structure of the system.

Termografisk undersökning med samtidig analys av rektaltemperatur, hjärtfrekvens, psykiska reaktioner och specifika blodparametrar av häst som behandlats med vibrationsboxen Vitafloor :

A number of studies in human medicine has documented positive effects of whole body vibration treatment in humans. The Vitafloor system, witch is based on treatment of horses with vibration, has the purpose to be used in training of healthy horses and as rehabilitation for horses with injuries in their musculosceletal system. The purpose of this study was to analyse what happens with a clinically healthy horse during treatment with Vitafloor. The methods used is mainly thermography before and after treatment, but also blood samples, measurement of rectal temperature, heart rate, clinical examination and observation of psychic reactions has been done. Statistic significant changes in skin temperature in hoofs and fetlocks of front legs has been observed after treatment with Vitafloor. Analyzing of the blood samples showed a tendency for decrease in Kalium, and two of the horses had changes in CK. No negative effect has been observed with the treatment of horses with Vitafloor, and the horses seems to like the treatment. .

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