Sökning: "transient vibrations"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden transient vibrations.

1. 1. Difficulties to Read and Write Under Lateral Vibration Exposure : Contextual Studies Of Train Passengers Ride Comfort

   Författare :Jerker Sundström; Shafiquzzaman Khan; Neil J. Mansfield; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lateral vibrations; passenger activities; reading; writing; sitting posture; frequency weighting; rated difficulty; field study; laboratory study; transient vibrations; stationary vibrations.; Vehicle engineering; Farkostteknik;

   Sammanfattning : Many people use the train both as a daily means of transport as well as a working place to carry out activities such as reading or writing. There are, however, several important factors in this environment that will hamper good performance of such activities. LÄS MER

3. 2. Prediction of discomfort due to transient whole body vibrations

   Författare :Peter Jönsson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk akustik; Engineering Acoustics;

   Sammanfattning : This Licentiate is about Whole Body Vibrations and focuses on transient vibrations with human's discomfort and motion assessment. Whole Body Vibrations occurs when a body is in contact with a vibrating surface. Whole Body Vibrations is a major problem in terrain vehicle, which affects both the physiological and psychological health and discomfort. LÄS MER

4. 3. Proton-Coupled Electron Transfer from Hydrogen-Bonded Phenols

   Författare :Tania Irebo; Leif Hammarström; James M. Mayer; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proton-coupled electron transfer; phenol oxidation; hydrogen bonds; artificial photosynthesis; promoting vibrations; proton transfer; laser flash-quench; transient absorption.; Physical chemistry; Fysikalisk kemi; Fysikalisk kemi; Physical Chemistry;

   Sammanfattning : Proton-coupled electron transfer (PCET) is one of the elementary reactions occurring in many chemical and biological systems, such as photosystem II where the oxidation of tyrosine (TyrZ) is coupled to deprotonation of the phenolic proton. This reaction is here modelled by the oxidation of a phenol covalently linked to a Ru(bpy)32+-moitey, which is photo-oxidized by a laser flash-quench method. LÄS MER

5. 4. Transient vibrations from dry clutch operation in heavy-duty truck powertrains : Modelling, simulation and validation

   Författare :Jakob Sjöstrand; Leif Kari; Ines Lopez Arteaga; Per Erik Austrell; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dry clutch system; Engagement; Disengagement; Dry-friction; LuGre friction model; Heavy-truck powertrain; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : For internal combustion engines used in heavy-duty vehicles, increased engine efficiency and consequently reduced CO2 emissions can be obtained if the engine speed can be kept within an optimal speed range. This requires swift and frequent gear shifts where the dry friction clutch is utilized. LÄS MER

7. 5. Attenuation of hand-held machine vibrations. Application of non-linear tuned vibration absorber

   Författare :Hans Lindell; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Impact machine; Hand-arm vibration; High frequency vibration; ATVA; Nonlinear tuned vibration absorber; White finger; HAVS; Transient vibration; Auto Tuned Vibration Absorber; Vibration dynamics; ISO 5349;

   Sammanfattning : Vibration injury in the hand-arm system from vibrating hand-held machines is one of the most common occupational health injuries and causes severe and often chronic nerve and vascular injuries to the operator. The objective with this study is to contribute to reduce hand-arm vibration injuries, first by developing methods of redesigning machines that will lower their vibration level and second to study how high frequency vibrations (HFV) above 1250 Hz effect the finger tissue which are not included in the current standard for risk evaluation. LÄS MER