Sökning: "Stephen Safe"

Hittade 4 avhandlingar innehållade orden Stephen Safe.

1. 1. Physico-chemical characteristics and quantitative structure-activity relationships of PCBs

   Författare :Patrik Andersson; Stephen Safe; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; polychlorinated biphenyls; PCBs; physico-chemical properties; statistical design; multivariate; PCA; PLS; biomagnification; BMF; bioassay; CYP1A; SAR; QSAR; REPs; risk assessment; Chemistry; Kemi; Chemistry; Kemi;

   Sammanfattning : The polychlorinated biphenyls (PCBs) comprise a group of 209 congeners varying in the number of chlorine atoms and substitution patterns. These compounds tend to be biomagnified in foodwebs and have been shown to induce an array of effects in exposed organisms. LÄS MER

3. 2. The optical properties of automatically darkening welding filters based on liquid crystal technology

   Författare :Stephen Palmer; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; Solid State Physics; fasta tillståndets fysik;

   Sammanfattning : This thesis addresses the problem of the poor optical angular properties displayed by automatically darkening welding filters that are based on liquid crystal technology. It is shown that by reducing thetwist-angle present in the liquid crystal cell to below that of 90° together with employment of a novel polariser arrangement, an optical shutter design using a double-cell construction is obtained thatpossesses a reduced angular transmittance variation when in the activated phase. LÄS MER

4. 3. Towards Safer and Risk-aware Motion Planning and Control for Robotic Systems

   Författare :Fernando S. Barbosa; Jana Tumova; Stephen Smith; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computer Science; Datalogi;

   Sammanfattning : Safety and risk-awareness are important properties for robotic systems, be it for protecting them from potentially dangerous internal states, or for avoiding collisions with obstacles and environmental hazards in disaster scenarios. Ensuring safety may be the role of more than one algorithmic layer in a system, each with varying assumptions and guarantees. LÄS MER

5. 4. Micro-crack initiation and propagation in fiber reinforced composites

   Författare :Andrejs Pupurs; Stephen L. Ogin; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Polymera konstruktionsmaterial; Polymeric Composite Materials;

   Sammanfattning : Predicting micro-damage initiation and evolution is one of the key challenges for safe design of fiber reinforced polymer composites. Micro-scale damage such as, for example, single fiber break may be unnoticeable and negligible during the initial service life of composite, however, with many loading and unloading cycles this initially micro-scale damage may propagate forming macroscopic scale cracks that can significantly reduce the service lifetime or even lead to unforeseen catastrophic failure of the composite structure. LÄS MER