Low power laser generated ultrasound : signal processing for time domain data acquisition

The use of low power modulated laser diode systems has previously been established as a suitable method for non-destructive laser generation of ultrasound. Using a quasi-continuous optical excitation amplified by an erbium-doped fibre amplifier (EDFA) allows flexible generation of ultrasonic waves, offering control of further parameters such as the frequency content or signal shape. In addition, pseudo-random binary sequences (PRBS) can be used to improve the detected impulse response. Here we compare two sequences, the m-sequence and the Golay code, and discuss the advantages and practical limits of their application with laser diode based optical excitation of ultrasound

Low power laser generated ultrasound : signal processing for time domain data acquisition

The use of low power modulated laser diode systems has previously been established as a suitable method for non-destructive laser generation of ultrasound. Using a quasi-continuous optical excitation amplified by an erbium-doped fibre amplifier (EDFA) allows flexible generation of ultrasonic waves, offering control of further parameters such as the frequency content or signal shape. In addition, pseudo-random binary sequences (PRBS) can be used to improve the detected impulse response. Here we compare two sequences, the m-sequence and the Golay code, and discuss the advantages and practical limits of their application with laser diode based optical excitation of ultrasound

‘Superbull’ males : what role do they play and what drives their appearance within the Doryteuthis gahi Patagonian Shelf population?

This work was funded by the Falkland Islands Government. Thanks are due to FCT/MCTES for financial support to CESAM (UID/AMB/50017/2019) through national funds and ERDF co-financing, under the Partnership Agreement for the PT2020 and Compete 2020 programs. This work was funded by the Falkland Islands Government. The study was conducted using E.U. Copernicus Marine Service Information. We are grateful to the scientific observers from the Falkland Islands fisheries department for sample collection and to the director of fisheries, John Barton, for supporting this work.Peer reviewedPublisher PD

Effect of Relative Volume on Radio Transmitter Expulsion in Subadult Common Carp

Expulsion of surgically implanted radio transmitters is a problem in some fish telemetry studies. We conducted a 109-d experiment to test the hypothesis that variation in relative volume of transmitters surgically implanted in subadult common carp Cyprinus carpio would affect transmitter expulsion. We also necropsied fish at the end of the experiment to evaluate histological evidence for the mechanism of expulsion. Survival rate was high during our experiment; all control fish and 88% of the fish subjected to the implantation surgery survived. Expulsion rate was low; of the 23 fish that received transmitters and survived the experiment, only two (9%) expelled the transmitters. One of these expulsions occurred through a rupture of the incision and the other occurred via the intestine. Retained transmitters were all encapsulated by tissue, and most exhibited multiple adhesions to the intestine, gonads, and body wall. Adhesions were more numerous in fish that received larger transmitters

A (1,2) Heterotic String with Gauge Symmetry

We construct a (1,2) heterotic string with gauge symmetry and determine its particle spectrum. This theory has a local N=1 worldsheet supersymmetry for left movers and a local N=2 worldsheet supersymmetry for right movers and describes particles in either two or three space-time dimensions. We show that fermionizing the bosons of the compactified N=1 space leads to a particle spectrum which has nonabelian gauge symmetry. The fermionic formulation of the theory corresponds to a dimensional reduction of self dual Yang Mills. We also give a worldsheet action for the theory and calculate the one-loop path integral.Comment: 17 pages, added reference

Phase II Audit Report - Energy & Water Audits of LLNL Facilities

This report describes Phase II of a project conducted for the Mechanical Utilities Division (UTel), Energy Management Program at Lawrence Livermore National Laboratory (LLNL) by Architectural Energy Corporation (AEC). The overall project covers energy efficiency and water conservation auditing services for 215 modular and prefabricated buildings at LLNL. The primary goal of this project is to demonstrate compliance with DOE Order 430.2A, Contractor Requirements Document section 2.d (2) Document, to demonstrate annual progress of at least 10 percent toward completing energy and water audits of all facilities. Although this project covers numerous buildings, they are all similar in design and use. The approach employed for completing audits for these facilities involves a ''model-similar building'' approach. In the model-similar building approach, similarities between groups of buildings are established and quantified. A model (or test case) building is selected and analyzed for each model-similar group using a detailed DOE-2 simulation. The results are extended to the group of similar buildings based on careful application of quantified similarities, or ''extension measures''. This approach leverages the relatively minor effort required to evaluate one building in some detail to a much larger population of similar buildings. The facility wide energy savings potential was calculated for a select set of measures that have reasonable payback based on the detailed building analysis and are otherwise desirable to the LLNL facilities staff. The selected measures are: (1) HVAC Tune-up. This is considered to be a ''core measure'', based on the energy savings opportunity and the impact on thermal comfort. All HVAC units in the study are assumed to be tuned up under this measure. See the Appendix for a detailed calculation by building and HVAC unit. (2) HVAC system scheduling. This is also considered to be a ''core measure'', based on the energy savings opportunity and ability to control units centrally during a shelter-in-place event. All HVAC units in the study are assumed to be controlled under this measure. See the Appendix for a detailed calculation by building and HVAC unit. (3) Cool roof. Savings estimates for the measure were applied to all roofs scheduled for replacement in the LLNL deficiency list. See the Appendix for a detailed calculation by building. (4) Window shading. Savings estimates for the measure were applied to all non-north facing windows. Although the simple payback is not a good for this measure, it should be considered for the associated benefits on thermal comfort and to alleviate some of the zoning and thermostat placement issues. (5) HVAC upgrade at normal replacement. Savings estimates for the measure were applied to all HVAC units scheduled for replacement on the LLNL deficiency list. A total of 642 units (about 55% of the total) are on the replacement list, so this represents a major opportunity. See the Appendix for a detailed calculation by building and HVAC unit. (6) Indirect/direct evaporative cooling. Savings estimates for the measure were applied to all HVAC units scheduled for replacement on the LLNL deficiency list. See the Appendix for a detailed calculation by building and HVAC unit. Due to the magnitude of the potential energy savings, this measure should be considered as the new generation IDEC systems become commercially available. (7) Super T-8's. Savings estimates for this measure were applied to all buildings in the study, assuming that the new generation lamps will be rotated in during normal lamp replacement operations. See the Appendix for a detailed calculation by building. (8) Occupancy sensors. Savings estimates for this measure were applied to buildings surveyed as candidates for occupancy sensors during the Level 1 audits. See the Appendix for a detailed calculation by building. (9) Remaining Lighting. Savings for this measure were calculated for each eligible fixture identified during the Level 1 Audits. See the Appendix for a detailed calculation by building and fixture. (10) Water Heating. Water heater and pipe insulation savings were calculated for storage water heaters. The number of storage water heaters in the study was estimated from the total number of buildings and the frequency of storage water heaters observed during the Level 2 audits, assuming one storage water heater per building

Coherence and superradiance from a plasma-based quasiparticle accelerator

Coherent light sources, such as free electron lasers, provide bright beams for biology, chemistry, physics, and advanced technological applications. Increasing the brightness of these sources requires progressively larger devices, with the largest being several km long (e.g., LCLS). Can we reverse this trend, and bring these sources to the many thousands of labs spanning universities, hospitals, and industry? Here we address this long-standing question by rethinking basic principles of radiation physics. At the core of our work is the introduction of quasi-particle-based light sources that rely on the collective and macroscopic motion of an ensemble of light-emitting charges to evolve and radiate in ways that would be unphysical when considering single charges. The underlying concept allows for temporal coherence and superradiance in fundamentally new configurations, providing radiation with clear experimental signatures and revolutionary properties. The underlying concept is illustrated with plasma accelerators but extends well beyond this case, such as to nonlinear optical configurations. The simplicity of the quasi-particle approach makes it suitable for experimental demonstrations at existing laser and accelerator facilities.Comment: 15 pages, 4 figure

PAUT inspection of complex shaped composite materials through 6 DOFs robotic manipulators

The requirement to increase inspection speeds for the non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides significant motivation for the use of six-axis robots for the deployment of NDT probes in these inspections. The IntACom project, developed by TWI Technology Centre (Wales) and supported by a number of major aerospace partners and the Welsh government, has produced a prototype robotic NDT system. The prototype system is capable of inspecting complex-geometry composite components with great time savings. Two six-axis robotic arms deploy end effectors carrying phased array ultrasonic testing (PAUT) probes. A simple-to-use graphical user interface (GUI) has been developed to control all aspects of the robotic inspection, from initial loading of part data, through scanning of the part to data analysis. The collaboration between TWI and the University of Strathclyde has boosted the establishment of new approaches for robotic tool-path generation, targeted to NDT inspections. Many unique features, such as the real-time B-scan for optimisation of PAUT settings and the external control of the robotic manipulators to allow returning to points of interest, increase the usefulness of the inspection process. This paper presents an overview of the project and of the research outcomes

Supersymmetry Breaking and Moduli Stabilization with Anomalous U(1) Gauge Symmetry

We examine the effects of anomalous U(1)_A gauge symmetry on soft supersymmetry breaking terms while incorporating the stabilization of the modulus-axion multiplet responsible for the Green-Schwarz (GS) anomaly cancellation mechanism. In case of the KKLT stabilization of the GS modulus, soft terms are determined by the GS modulus mediation, the anomaly mediation and the U(1)_A mediation which are generically comparable to each other, thereby yielding the mirage mediation pattern of superparticle masses at low energy scale. Independently of the mechanism of moduli stabilization and supersymmetry breaking, the U(1)_A D-term potential can not be an uplifting potential for de Sitter vacuum when the gravitino mass is smaller than the Planck scale by many orders of magnitude. We also discuss some features of the supersymmetry breaking by red-shifted anti-brane which is a key element of the KKLT moduli stabilization.Comment: 32 pages; references are adde

Size-dependent change in body shape and its possible ecological role in the Patagonian squid (Doryteuthis gahi) in the Southwest Atlantic

This study was supported by funding from the Falkland Islands Government. We are grateful to the scientific observers from the Falkland Islands Fisheries Department for sample collection and Beverley Reid for collecting traditional morphometric measurements and to three anonymous referees for their comments which greatly improved the manuscript. We thank the Director of Fisheries, John Barton, for supporting this work. The MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland, funded by the Scottish Funding Council and contributing institutions; grant reference HR09011) is gratefully acknowledged. Thanks are due to FCT/MCTES for financial support to CESAM (UID/AMB/50017/2019) through national funds and ERDF co-financing, under the Partnership Agreement for the PT2020 and Compete 2020 programsPeer reviewedPostprin