Sökning: "second cycle"

Visar resultat 21 - 25 av 600 avhandlingar innehållade orden second cycle.

  1. 21. Generation, characterization and application of infrared few-cycle light pulses

    Författare :Ivan Sytcevich; NanoLund: Centre for Nanoscience; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Few-cycle pulses; pulse characterization; optical parametric amplification; Fysicumarkivet A:2022:Sytcevich;

    Sammanfattning : In recent decades, laser systems emitting pulses of light containing only a few electric field oscillations under their envelope have become common in many ultrafast optics laboratories. Owing to unique temporal characteristics and achieving extreme field strengths, these so-­called few­-cycle pulses have been instrumental in unlocking new regimes of light-­matter interaction. LÄS MER

  3. 22. Allopregnanolone effects in women : clinical studies in relation to the menstrual cycle, premenstrual dysphoric disorder and oral contraceptive use

    Författare :Erika Timby; Marie Bixo; Torbjörn Bäckström; Anna-Carin N Wihlbäck; C Neill Epperson; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Allopregnanolone; GABAA receptor; menstrual cycle; premenstrual dysphoric disorder; saccadic eye velocity; oral contraceptives; hypothalamic amenorrhea;

    Sammanfattning : Background: Premenstrual dysphoric disorder (PMDD) affects 3–8% of women in fertile ages. Combined oral contraceptives (OCs) are widely used and some users experience adverse mood effects. The cyclicity of PMDD symptoms coincides with increased endogenous levels of allopregnanolone after ovulation. LÄS MER

  4. 23. Two-Level Multi-Objective Genetic Algorithm for Risk-Based Life Cycle Cost Analysis

    Författare :Yamur K. Al-Douri; Uday Kumar; Jan Lundberg; Hussan Hamodi; Ahmed Al-Dubai; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Artificial intelligence AI ; Life cycle cost LCC ; Machine learning ML ; Multi-objective genetic algorithm MOGA ; Risk-based life cycle cost LCC ; Tunnel fans; Two-level system; Operation and Maintenance Engineering; Drift och underhållsteknik;

    Sammanfattning : Artificial intelligence (AI) is one of the fields in science and engineering and encompasses a wide variety of subfields, ranging from general areas (learning and perception) to specific topics, such as mathematical theorems. AI and, specifically, multi-objective genetic algorithms (MOGAs) for risk-based life cycle cost (LCC) analysis should be performed to estimate the optimal replacement time of tunnel fan systems, with a view towards reducing the ownership cost and the risk cost and increasing company profitability from an economic point of view. LÄS MER

  5. 24. A Life Cycle Approach to Environmental Sustainability in Aggregate Production Systems

    Författare :Christina Lee; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Aggregates; Gravel; Sand; LCA; Production Systems; Sustainability; Life Cycle Assessment; Environmental Management; EPDs; Quarries; Tool Development; Environmental Impact; Environmental Product Declarations; Construction Products;

    Sammanfattning : Rock materials, such as sand, gravel, and crushed rock, serve as the foundation of our society. Known collectively as aggregates, these materials are essential for building foundations, concrete, and roads, making them the second most extracted material globally after water. LÄS MER

  7. 25. Double Compression-Expansion Engine Concepts : Experimental and simulation study of a split-cycle concept for improved brake efficiency

    Författare :Nhut Lam; Förbränningsmotorer; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Split-cycle; high efficiency; 1D-modeling; Engine experimetns; heavy-duty engine;

    Sammanfattning : The four-stroke engine was invented by Nikolaus Otto during the second half of the 19th century. Although a lot of technological improvements have been made over the years, the operating principle with four-strokes remains the same. The need and desire of engines with even higher fuel-efficiency is a motivation to study alternative engine concepts. LÄS MER