variable time
Recently Published Documents

AbstractWe report nanosecond (ns) cavity-dumped operation of a low-cost diode-pumped Cr:LiSAF laser around 1000 nm. The system is pumped with one 1-W single-emitter multimode diode at 665 nm. A Pockell cell (PC) and thin-film-polarizer (TFP) combination placed inside the cavity chops up an adjustable portion of the intracavity power and creates a variable time-dependent output coupler. Via adjusting the length and magnitude of the electrical signal going into the PC, output pulses with pulsewidths in the 2.5–500 ns range and with peak power levels above 10 W are generated at repetition rates up to 100 kHz. The central wavelength of the pulses could be smoothly tuned in the 985–1030 nm region, and is only limited by the anti-reflection coating bandwidth of the current PC and TFP. This versatile nanosecond source with 100 nJ level energies could serve as an attractive low-cost seed source for Yb-based amplifiers, including the cryogenic Yb:YLF systems.

AbstractEvaluability assessments (EAs) have differing definitions, focus on various aspects of evaluation, and have been implemented inconsistently in the last several decades. Climate change adaptation (CCA) programming presents particular challenges for evaluation given shifting baselines, variable time horizons, adaptation as a moving target, and uncertainty inherent to climate change and its extreme and varied effects. The Adaptation Fund Technical Evaluation Reference Group (AF-TERG) developed a framework to assess the extent to which the Fund’s portfolio of projects has in place structures, processes, and resources capable of supporting credible and useful monitoring, evaluation, and learning (MEL). The framework was applied on the entire project portfolio to determine the level of evaluability and make recommendations for improvement. This chapter explores the assessment’s findings on designing programs and projects to help minimize the essential challenges in the field. It discusses how the process of EA can help identify opportunities for strengthening both evaluability and a project’s MEL more broadly. A key conclusion was that the strength and quality of a project’s overall approach to MEL is a major determinant of a project’s evaluability. Although the framework was used retroactively, EAs could also be used prospectively as quality assurance tools at the pre-implementation stage.