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Mechanical Strain Measurement from Coda Wave Interferometry

NASA Astrophysics Data System (ADS)

Azzola, J.; Schmittbuhl, J.; Zigone, D.; Masson, F.; Magnenet, V.

2017-12-01

Coda Wave Interferometry (CWI) aims at tracking small changes in solid materials like rocks where elastic waves are diffusing. They are intensively sampling the medium, making the technique much more sensitive than those relying on direct wave arrivals. Application of CWI to ambient seismic noise has found a large range of applications over the past years like for multiscale imaging but also for monitoring complex structures such as regional faults or reservoirs (Lehujeur et al., 2015). Physically, observed changes are typically interpreted as small variations of seismic velocities. However, this interpretation remains questionable. Here, a specific focus is put on the influence of the elastic deformation of the medium on CWI measurements. The goal of the present work is to show from a direct numerical and experimental modeling that deformation signal also exists in CWI measurements which might provide new outcomes for the technique.For this purpose, we model seismic wave propagation within a diffusive medium using a spectral element approach (SPECFEM2D) during an elastic deformation of the medium. The mechanical behavior is obtained from a finite element approach (Code ASTER) keeping the mesh grid of the sample constant during the whole procedure to limit numerical artifacts. The CWI of the late wave arrivals in the synthetic seismograms is performed using both a stretching technique in the time domain and a frequency cross-correlation method. Both show that the elastic deformation of the scatters is fully correlated with time shifts of the CWI differently from an acoustoelastic effect. As an illustration, the modeled sample is chosen as an effective medium aiming to mechanically and acoustically reproduce a typical granitic reservoir rock.Our numerical approach is compared to experimental results where multi-scattering of an acoustic wave through a perforated loaded Au4G (Dural) plate is performed at laboratory scale. Experimental and numerical results of the strain influence on CWI are shown to be consistent.Lehujeur, M., J. Vergne, J. Schmittbuhl, and A. Maggi. Characterization of ambient seismic noise near a deep geothermal reservoir and implications for interferometric methods: a case study in northern alsace, france. Geothermal Energy, 3(1):1-17, 2015.
Material State Awareness for Composites Part I: Precursor Damage Analysis Using Ultrasonic Guided Coda Wave Interferometry (CWI).

PubMed

Patra, Subir; Banerjee, Sourav

2017-12-16

Detection of precursor damage followed by the quantification of the degraded material properties could lead to more accurate progressive failure models for composite materials. However, such information is not readily available. In composite materials, the precursor damages-for example matrix cracking, microcracks, voids, interlaminar pre-delamination crack joining matrix cracks, fiber micro-buckling, local fiber breakage, local debonding, etc.-are insensitive to the low-frequency ultrasonic guided-wave-based online nondestructive evaluation (NDE) or Structural Health Monitoring (SHM) (~100-~500 kHz) systems. Overcoming this barrier, in this article, an online ultrasonic technique is proposed using the coda part of the guided wave signal, which is often neglected. Although the first-arrival wave packets that contain the fundamental guided Lamb wave modes are unaltered, the coda wave packets however carry significant information about the precursor events with predictable phase shifts. The Taylor-series-based modified Coda Wave Interferometry (CWI) technique is proposed to quantify the stretch parameter to compensate the phase shifts in the coda wave as a result of precursor damage in composites. The CWI analysis was performed on five woven composite-fiber-reinforced-laminate specimens, and the precursor events were identified. Next, the precursor damage states were verified using high-frequency Scanning Acoustic Microscopy (SAM) and optical microscopy imaging.
In-situ changes in the elastic wave velocity of rock with increasing temperature using high-resolution coda wave interferometry

NASA Astrophysics Data System (ADS)

Griffiths, Luke; Heap, Michael; Lengliné, Olivier; Schmittbuhl, Jean; Baud, Patrick

2017-04-01

Rock undergoes fluctuations in temperature in various settings in Earth's crust, including areas of volcanic or geothermal activity, or industrial environments such as hydrocarbon or geothermal reservoirs. Changes in temperature can cause thermal stresses that can result in the formation of microcracks, which affect the mechanical, physical, and transport properties of rocks. Of the affected physical properties, the elastic wave velocity of rock is particularly sensitive to microcracking. Monitoring the evolution of elastic wave velocity during the thermal stressing of rock therefore provides valuable insight into thermal cracking processes. One monitoring technique is Coda Wave Interferometry (CWI), which infers high-resolution changes in the medium from changes in multiple-scattered elastic waves. We have designed a new experimental setup to perform CWI whilst cyclically heating and cooling samples of granite (cylinders of 20 mm diameter and 40 mm length). In our setup, the samples are held between two pistons within a tube furnace and are heated and cooled at a rate of 1 °C/min to temperatures of up to 300 °C. Two high temperature piezo-transducers are each in contact with an opposing face of the rock sample. The servo-controlled uniaxial press compensates for the thermal expansion and contraction of the pistons and the sample, keeping the coupling between the transducers and the sample, and the axial force acting on the sample, constant throughout. Our setup is designed for simultaneous acoustic emission monitoring (AE is commonly used as a proxy for microcracking), and so we can follow thermal microcracking precisely by combining the AE and CWI techniques. We find that during the first heating/cooling cycle, the onset of thermal microcracking occurs at a relatively low temperature of around 65 °C. The CWI shows that elastic wave velocity decreases with increasing temperature and increases during cooling. Upon cooling, back to room temperature, there is an irreversible relative decrease in velocity of several percent associated with the presence of new thermal microcracks. Our data suggest that few new microcracks were formed when the same sample was subject to subsequent identical heating/cooling cycles as changes in the elastic wave velocity are near-reversible. Our results shed light on the temperature conditions required for thermal microcracking and the influence of temperature on elastic wave velocity with applications to a wide variety of geoscientific disciplines.
Towards monitoring the englacial fracture state using virtual-reflector seismology

NASA Astrophysics Data System (ADS)

Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

2018-04-01

In seismology, coda wave interferometry (CWI) is an effective tool to monitor time-lapse changes using later arriving, multiply scattered coda waves. Typically, CWI relies on an estimate of the medium's impulse response. The latter is retrieved through simple time-averaging of receiver-receiver cross-correlations of the ambient field, i.e. seismic interferometry (SI). In general, the coda are induced by heterogeneities in the Earth. Being comparatively homogeneous, however, ice bodies such as glaciers and ice sheets exhibit little scattering. In addition, the temporal stability of the time-averaged cross-correlations suffers from temporal variations in the distribution and amplitude of the passive seismic sources. Consequently, application of CWI to ice bodies is currently limited. Nevertheless, fracturing and changes in the englacial macroscopic water content alter the bulk elastic properties of ice bodies, which can be monitored with cryoseismological measurements. To overcome the current limited applicability of CWI to ice bodies, we therefore introduce virtual-reflector seismology (VRS). VRS relies on a so-called multidimensional deconvolution (MDD) process of the time-averaged crosscorrelations. The technique results in the retrieval of a medium response that includes virtual reflections from a contour of receivers enclosing the region of interest (i.e., the region to be monitored). The virtual reflections can be interpreted as artificial coda replacing the (lacking) natural scattered coda. Hence, this artificial coda might be exploited for the purpose of CWI. From an implementation point of view, VRS is similar to SI by MDD, which, as its name suggests, also relies on a multidimensional deconvolution process. SI by MDD, however, does not generate additional virtual reflections. Advantageously, both techniques mitigate spurious coda changes associated with temporal variations in the distribution and amplitude of the passive seismic sources. In this work, we apply SI by MDD and VRS to synthetic and active seismic surface-wave data. The active seismic data were acquired on Glacier de la Plaine Morte, Switzerland. We successfully retrieve virtual reflections through the application of VRS to this active seismic data. In application to both synthetic and active seismic data, we show the potential of VRS to monitor time-lapse changes. In addition, we find that SI by MDD allows for a more accurate determination of phase velocity.
Monitoring the self-healing process of biomimetic mortar using coda wave interferometry method

NASA Astrophysics Data System (ADS)

Liu, Shukui; Basaran, Zeynep; Zhu, Jinying; Ferron, Raissa

2014-02-01

Internal stresses might induce microscopic cracks in concrete, which can provide pathways for ingress of harmful chemicals and can lead to loss of strength. Recent research in concrete materials suggests that it might be possible to develop a smart cement-based material that is capable of self-healing by leveraging the metabolic activity of microorganisms to provide biomineralization. Limited research on biomineralization in cement-based systems has shown promising results that healing of cracks can occur on the surface of concrete and reduce permeability. This paper presents the results from an investigation regarding the potential for a cement-based material to repair itself internally through biomineralization. Compressive strength test and coda wave interferometry (CWI) analyses were conducted on mortar samples that were loaded to 70% of their compressive strength and cured in different conditions. Experimental results indicate that the damaged mortar samples with microorganisms showed significantly higher strength development and higher increase of ultrasonic wave velocity compared to samples without microorganisms at 7 and 28 days.
Numerical modeling of time-lapse monitoring of CO2 sequestration in a layered basalt reservoir

USGS Publications Warehouse

Khatiwada, M.; Van Wijk, K.; Clement, W.P.; Haney, M.

2008-01-01

As part of preparations in plans by The Big Sky Carbon Sequestration Partnership (BSCSP) to inject CO2 in layered basalt, we numerically investigate seismic methods as a noninvasive monitoring technique. Basalt seems to have geochemical advantages as a reservoir for CO2 storage (CO2 mineralizes quite rapidly while exposed to basalt), but poses a considerable challenge in term of seismic monitoring: strong scattering from the layering of the basalt complicates surface seismic imaging. We perform numerical tests using the Spectral Element Method (SEM) to identify possibilities and limitations of seismic monitoring of CO2 sequestration in a basalt reservoir. While surface seismic is unlikely to detect small physical changes in the reservoir due to the injection of CO2, the results from Vertical Seismic Profiling (VSP) simulations are encouraging. As a perturbation, we make a 5%; change in wave velocity, which produces significant changes in VSP images of pre-injection and post-injection conditions. Finally, we perform an analysis using Coda Wave Interferometry (CWI), to quantify these changes in the reservoir properties due to CO2 injection.
Tracking changes in volcanic systems with seismic Interferometry

USGS Publications Warehouse

Haney, Matt; Alicia J. Hotovec-Ellis,; Bennington, Ninfa L.; Silvio De Angelis,; Clifford Thurber,

2014-01-01

The detection and evaluation of time-dependent changes at volcanoes form the foundation upon which successful volcano monitoring is built. Temporal changes at volcanoes occur over all time scales and may be obvious (e.g., earthquake swarms) or subtle (e.g., a slow, steady increase in the level of tremor). Some of the most challenging types of time-dependent change to detect are subtle variations in material properties beneath active volcanoes. Although difﬁcult to measure, such changes carry important information about stresses and ﬂuids present within hydrothermal and magmatic systems. These changes are imprinted on seismic waves that propagate through volcanoes. In recent years, there has been a quantum leap in the ability to detect subtle structural changes systematically at volcanoes with seismic waves. The new methodology is based on the idea that useful seismic signals can be generated “at will” from seismic noise. This means signals can be measured any time, in contrast to the often irregular and unpredictable times of earthquakes. With seismic noise in the frequency band 0.1–1 Hz arising from the interaction of the ocean with the solid Earth known as microseisms, researchers have demonstrated that cross-correlations of passive seismic recordings between pairs of seismometers yield coherent signals (Campillo and Paul 2003; Shapiro and Campillo 2004). Based on this principle, coherent signals have been reconstructed from noise recordings in such diverse ﬁelds as helioseismology (Rickett and Claerbout 2000), ultrasound (Weaver and Lobkis 2001), ocean acoustic waves (Roux and Kuperman 2004), regional (Shapiro et al. 2005; Sabra et al. 2005; Bensen et al. 2007) and exploration (Draganov et al. 2007) seismology, atmospheric infrasound (Haney 2009), and studies of the cryosphere (Marsan et al. 2012). Initial applications of ambient seismic noise were to regional surface wave tomography (Shapiro et al. 2005). Brenguier et al. (2007) were the ﬁrst to use ambient noise tomography (ANT) to map the 3D structure of a volcanic interior (at Piton de la Fournaise). Subsequent studies have imaged volcanoes with ANT at Okmok (Masterlark et al. 2010), Toba (Stankiewicz et al. 2010), Katmai (Thurber et al. 2012), Asama (Nagaoka et al. 2012), Uturuncu (Jay et al. 2012), and Kilauea (Ballmer et al. 2013b). In addition, Ma et al. (2013) have imaged a scatterer in the volcanic region of southern Peru by applying array techniques to ambient noise correlations. Prior to and in tandem with the development of ANT, researchers discovered that repeating earthquakes, which often occur at volcanoes, could be used to monitor subtle time-dependent changes with a technique known as the doublet method or coda wave interferometry (CWI) (Poupinet et al. 1984; Roberts et al. 1992; Ratdomopurbo and Poupinet 1995; Snieder et al. 2002; Pandolﬁ et al. 2006; Wegler et al. 2006; Martini et al. 2009; Haney et al. 2009; De Angelis 2009; Nagaoka et al. 2010; Battaglia et al. 2012; Erdem and Waite 2005; Hotovec-Ellis et al. 2014). Chaput et al. (2012) have also used scattered waves from Strombolian eruption coda at Erebus volcano to image the reﬂectivity of the volcanic interior with body wave interferometry. However, CWI in its original form was limited in that repeating earthquakes, or doublets, were not always guaranteed to occur. With the widespread use of noise correlations in seismology following the groundbreaking work by Campillo and Paul (2003) and Shapiro et al. (2005), it became evident that the nature of the ambient seismic ﬁeld, due to its oceanic origin, enabled the continuous monitoring of subtle, time-dependent changes at both fault zones (Wegler and Sens-Schönfelder 2007; Brenguier et al. 2008b; Wegler et al. 2009; Sawazaki et al. 2009; Tatagi et al. 2012) and volcanoes (Sens-Schönfelder and Wegler 2006; Brenguier et al. 2008a) without the need for repeating earthquakes. Seismic precursors to eruptions based on ambient noise we
Constraining the depth of the time-lapse changes of P- and S-wave velocities in the first year after the 2011 Tohoku earthquake, Japan

NASA Astrophysics Data System (ADS)

Sawazaki, K.; Kimura, H.; Uchida, N.; Takagi, R.; Snieder, R.

2012-12-01

Using deconvolutions of vertical array of KiK-net (nationwide strong-motion seismograph digital network in Japan) records and applying coda wave interferometry (CWI) to Hi-net (high-sensitivity seismograph network in Japan; collocated with a borehole receiver of KiK-net) borehole records, we constrain the responsible depth of the medium changes associated with the 2011 Tohoku earthquake (MW9.0). There is a systematic reduction in VS up to 6% in the shallow subsurface which experienced strong dynamic strain by the Tohoku earthquake. In contrast, both positive and negative changes are observed for VP, which are less than 2% for both directions. We propose that this discrepancy between the changes of VS and VP is explained by the behavior of shear and bulk moduli of a porous medium exposed to an increase of excess pore fluid pressure. At many stations, VS recovers proportional to logarithm of the lapse time after the mainshock, and mostly recovers to the reference value obtained before the mainshock in one year. However, some stations that have been exposed by additional strong motions of aftershocks and/or other earthquakes take much longer time for the recovery. The CWI technique applied to horizontal components of S-coda reveals a velocity reduction up to 0.2% widely along the coastline of northeastern Japan. For the vertical component of P-coda, however, the velocity change is mostly less than 0.1% at the same region. From single scattering model including P-S and S-P conversion scatterings, we verify that both components are sensitive to VS change around the source, but the vertical component of P-coda is sensitive to VP change around the receiver. Consequently, the difference in velocity changes revealed from the horizontal and vertical components represents the difference of VS and VP changes near the receiver. As the conclusion, VS reduction ratio in the deep lithosphere is smaller than that at the shallow ground by 1 to 2 orders.
Cerebrovascular risk factors for patients with cerebral watershed infarction: A case-control study based on computed tomography angiography in a population from Southwest China.

PubMed

Dong, Mei-Xue; Hu, Ling; Huang, Yuan-Jun; Xu, Xiao-Min; Liu, Yang; Wei, You-Dong

2017-07-01

To determine cerebrovascular risk factors for patients with cerebral watershed infarction (CWI) from Southwest China.Patients suffering from acute ischemic stroke were categorized into internal CWI (I-CWI), external CWI (E-CWI), or non-CWI (patients without CWI) groups. Clinical data were collected and degrees of steno-occlusion of all cerebral arteries were scored. Arteries associated with the circle of Willis were also assessed. Data were compared using Pearson chi-squared tests for categorical data and 1-way analysis of variance with Bonferroni post hoc tests for continuous data, as appropriate. Multivariate binary logistic regression analysis was performed to determine independent cerebrovascular risk factors for CWI.Compared with non-CWI, I-CWI had higher degrees of steno-occlusion of the ipsilateral middle cerebral artery, ipsilateral carotid artery, and contralateral middle cerebral artery. E-CWI showed no significant differences. All the 3 arteries were independent cerebrovascular risk factors for I-CWI confirmed by multivariate binary logistic regression analysis. I-CWI had higher degrees of steno-occlusion of the ipsilateral middle cerebral artery compared with E-CWI. No significant differences were found among arteries associated with the circle of Willis.The ipsilateral middle cerebral artery, carotid artery, and contralateral middle cerebral artery were independent cerebrovascular risk factors for I-CWI. No cerebrovascular risk factor was identified for E-CWI.
Breath-hold time during cold water immersion: effects of habituation with psychological training.

PubMed

Barwood, Martin J; Datta, Avijit K; Thelwell, Richard C; Tipton, Michael J

2007-11-01

The loss of the conscious control of respiration on whole body cold water immersion (CWI) can result in the aspiration of water and drowning. Repeated CWI reduces the respiratory drive evoked by CWI and should prolong breath-hold time on CWI (BHmax(CWI)). Psychological skills training (PST) can also increase BHmax(CWI) by improving the ability of individuals to consciously suppress the drive to breathe. This study tested the hypothesis that combining PST and repeated CWI would extend BHmax(CWI) beyond that seen following only repeated CWI. There were 20 male subjects who completed two 2.5-min, head-out breath-hold CWI (BH1 and BH2) in water at 12 degrees C. Following BH1, subjects were matched on BHmax(CWI) and allocated to a habituation (HAB) group or a habituation plus PST group (H+PST). Between BH1 and BH2 both experimental groups undertook five 2.5-min CWI on separate days, during which they breathed freely. The H+PST also received psychological training to help tolerate cold and suppress the drive to breathe on immersion to extend BHmax(CWI). During BH1, mean BHmax(CWI) (+/- SD) in the HAB group was 22.00 (10.33) s and 22.38 (10.65) s in the H+PST. After the five free-breathing CWI, both groups had a longer BHmax(CWI) in BH2. The HAB group improved by 14.13 (20.21) s, an increase of 73%. H+PST improved by 26.86 (24.70) s, a 120% increase. No significant differences were identified between the groups. Habituation significantly increases BHmax on CWI, the addition of PST did not result in statistically significant improvements in BHmax(CWI), but may have practical significance.
Combat Wound Initiative program.

PubMed

Stojadinovic, Alexander; Elster, Eric; Potter, Benjamin K; Davis, Thomas A; Tadaki, Doug K; Brown, Trevor S; Ahlers, Stephen; Attinger, Christopher E; Andersen, Romney C; Burris, David; Centeno, Jose; Champion, Hunter; Crumbley, David R; Denobile, John; Duga, Michael; Dunne, James R; Eberhardt, John; Ennis, William J; Forsberg, Jonathan A; Hawksworth, Jason; Helling, Thomas S; Lazarus, Gerald S; Milner, Stephen M; Mullick, Florabel G; Owner, Christopher R; Pasquina, Paul F; Patel, Chirag R; Peoples, George E; Nissan, Aviram; Ring, Michael; Sandberg, Glenn D; Schaden, Wolfgang; Schultz, Gregory S; Scofield, Tom; Shawen, Scott B; Sheppard, Forest R; Stannard, James P; Weina, Peter J; Zenilman, Jonathan M

2010-07-01

The Combat Wound Initiative (CWI) program is a collaborative, multidisciplinary, and interservice public-private partnership that provides personalized, state-of-the-art, and complex wound care via targeted clinical and translational research. The CWI uses a bench-to-bedside approach to translational research, including the rapid development of a human extracorporeal shock wave therapy (ESWT) study in complex wounds after establishing the potential efficacy, biologic mechanisms, and safety of this treatment modality in a murine model. Additional clinical trials include the prospective use of clinical data, serum and wound biomarkers, and wound gene expression profiles to predict wound healing/failure and additional clinical patient outcomes following combat-related trauma. These clinical research data are analyzed using machine-based learning algorithms to develop predictive treatment models to guide clinical decision-making. Future CWI directions include additional clinical trials and study centers and the refinement and deployment of our genetically driven, personalized medicine initiative to provide patient-specific care across multiple medical disciplines, with an emphasis on combat casualty care.
Effect of immediate and delayed cold water immersion after a high intensity exercise session on subsequent run performance.

PubMed

Brophy-Williams, Ned; Landers, Grant; Wallman, Karen

2011-01-01

The purpose of the study was to determine the effects of cold water immersion (CWI) performed immediately or 3 h after a high intensity interval exercise session (HIIS) on next-day exercise performance. Eight male athletes performed three HIIS at 90%VO2max velocity followed by either a passive recovery (CON), CWI performed immediately post-exercise (CWI(0)) or CWI performed 3 h post-exercise (CWI(3)). Recovery trials were performed in a counter balanced manner. Participants then returned 24 h later and completed a muscle soreness and a totally quality recovery perception (TQRP) questionnaire, which was then followed by the Yoyo Intermittent Recovery Test [level 1] (YRT). Venous blood samples were collected pre-HIIS and pre-YRT to determine C-Reactive Protein (CRP) levels. Significantly more shuttles were performed during the YRT following CWI(0) compared to the CON trial (p=0.017, ES = 0. 8), while differences between the CWI(3) and the CON trials approached significance (p = 0.058, ES = 0.5). Performance on the YRT between the CWI(0) and CWI(3) trials were similar (p = 0.147, ES = 0. 3). Qualitative analyses demonstrated a 98% and 92% likely beneficial effect of CWI(0) and CWI(3) on next day performance, compared to CON, respectively, while CWI(0) resulted in a 79% likely benefit when compared to CWI(3). CRP values were significantly lower pre-YRT, compared to baseline, following CWI(0) (p = 0.0.36) and CWI(3) (p = 0.045), but were similar for CON (p = 0.157). Muscle soreness scores were similar between trials (p = 1.10), while TQRP scores were significantly lower for CON compared to CWI(0) (p = 0.002 ) and CWI(3) (p = 0.024). Immediate CWI resulted in superior next-day YRT performance compared to CON, while delayed (3 h) CWI was also likely to be beneficial. Qualitative analyses suggested that CWI(0) resulted in better performance than CWI(3). These results are important for athletes who do not have immediate access to CWI following exercise. Key pointsPerformance of cold water immersion as a recovery procedure following exercise is better than performing no recovery procedureAthletes, coaches and sport trainers should implement cold water immersion post-exercise irrespective of the time of administration.Where possible, cold water immersion should be performed immediately post-exercise to gain maximal recovery benefits.
Effect of post-exercise hydrotherapy water temperature on subsequent exhaustive running performance in normothermic conditions.

PubMed

Dunne, Alan; Crampton, David; Egaña, Mikel

2013-09-01

Despite the widespread use of cold water immersion (CWI) in normothermic conditions, little data is available on its effect on subsequent endurance performance. This study examined the effect of CWI as a recovery strategy on subsequent running performance in normothermic ambient conditions (∼22°C). Nine endurance-trained men completed two submaximal exhaustive running bouts on three separate occasions. The running bouts (Ex1 and Ex2) were separated by 15min of un-immersed seated rest (CON), hip-level CWI at 8°C (CWI-8) or hip-level CWI at 15°C (CWI-15). Intestinal temperature, blood lactate and heart rate were recorded throughout and V˙O2, running economy and exercise times were recorded during the running sessions. Running time to failure (min) during Ex2 was significantly (p<0.05, ES=0.7) longer following CWI-8 (27.7±6.3) than CON (23.3±5) but not different between CWI-15 (26.3±3.4) and CON (p=0.06, ES=0.7) or CWI-8 and CWI-15 (p=0.4, ES=0.2). Qualitative analyses showed a 95% and 89% likely beneficial effect of CWI-8 and CWI-15 during Ex2 compared with CON, respectively. Time to failure during Ex2 was significantly shorter than Ex1 only during the CON condition. Intestinal temperature and HR were significantly lower for most of Ex2 during CWI-8 and CWI-15 compared with CON but they were similar at failure for the three conditions. Blood lactate, running economy and V˙O2 were not altered by CWI. These data indicate that a 15min period of cold water immersion applied between repeated exhaustive exercise bouts significantly reduces intestinal temperature and enhances post-immersion running performance in normothermic conditions. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Muscle, skin and core temperature after -110°c cold air and 8°c water treatment.

PubMed

Costello, Joseph Thomas; Culligan, Kevin; Selfe, James; Donnelly, Alan Edward

2012-01-01

The aim of this investigation was to elucidate the reductions in muscle, skin and core temperature following exposure to -110°C whole body cryotherapy (WBC), and compare these to 8°C cold water immersion (CWI). Twenty active male subjects were randomly assigned to a 4-min exposure of WBC or CWI. A minimum of 7 days later subjects were exposed to the other treatment. Muscle temperature in the right vastus lateralis (n=10); thigh skin (average, maximum and minimum) and rectal temperature (n=10) were recorded before and 60 min after treatment. The greatest reduction (P<0.05) in muscle (mean ± SD; 1 cm: WBC, 1.6 ± 1.2°C; CWI, 2.0 ± 1.0°C; 2 cm: WBC, 1.2 ± 0.7°C; CWI, 1.7 ± 0.9°C; 3 cm: WBC, 1.6 ± 0.6°C; CWI, 1.7 ± 0.5°C) and rectal temperature (WBC, 0.3 ± 0.2°C; CWI, 0.4 ± 0.2°C) were observed 60 min after treatment. The largest reductions in average (WBC, 12.1 ± 1.0°C; CWI, 8.4 ± 0.7°C), minimum (WBC, 13.2 ± 1.4°C; CWI, 8.7 ± 0.7°C) and maximum (WBC, 8.8 ± 2.0°C; CWI, 7.2 ± 1.9°C) skin temperature occurred immediately after both CWI and WBC (P<0.05). Skin temperature was significantly lower (P<0.05) immediately after WBC compared to CWI. The present study demonstrates that a single WBC exposure decreases muscle and core temperature to a similar level of those experienced after CWI. Although both treatments significantly reduced skin temperature, WBC elicited a greater decrease compared to CWI. These data may provide information to clinicians and researchers attempting to optimise WBC and CWI protocols in a clinical or sporting setting.
Atom Interferometry for Fundamental Physics and Gravity Measurements in Space

NASA Technical Reports Server (NTRS)

Kohel, James M.

2012-01-01

Laser-cooled atoms are used as freefall test masses. The gravitational acceleration on atoms is measured by atom-wave interferometry. The fundamental concept behind atom interferometry is the quantum mechanical particle-wave duality. One can exploit the wave-like nature of atoms to construct an atom interferometer based on matter waves analogous to laser interferometers.
Muscle, Skin and Core Temperature after −110°C Cold Air and 8°C Water Treatment

PubMed Central

Costello, Joseph Thomas; Culligan, Kevin; Selfe, James; Donnelly, Alan Edward

2012-01-01

The aim of this investigation was to elucidate the reductions in muscle, skin and core temperature following exposure to −110°C whole body cryotherapy (WBC), and compare these to 8°C cold water immersion (CWI). Twenty active male subjects were randomly assigned to a 4-min exposure of WBC or CWI. A minimum of 7 days later subjects were exposed to the other treatment. Muscle temperature in the right vastus lateralis (n = 10); thigh skin (average, maximum and minimum) and rectal temperature (n = 10) were recorded before and 60 min after treatment. The greatest reduction (P<0.05) in muscle (mean ± SD; 1 cm: WBC, 1.6±1.2°C; CWI, 2.0±1.0°C; 2 cm: WBC, 1.2±0.7°C; CWI, 1.7±0.9°C; 3 cm: WBC, 1.6±0.6°C; CWI, 1.7±0.5°C) and rectal temperature (WBC, 0.3±0.2°C; CWI, 0.4±0.2°C) were observed 60 min after treatment. The largest reductions in average (WBC, 12.1±1.0°C; CWI, 8.4±0.7°C), minimum (WBC, 13.2±1.4°C; CWI, 8.7±0.7°C) and maximum (WBC, 8.8±2.0°C; CWI, 7.2±1.9°C) skin temperature occurred immediately after both CWI and WBC (P<0.05). Skin temperature was significantly lower (P<0.05) immediately after WBC compared to CWI. The present study demonstrates that a single WBC exposure decreases muscle and core temperature to a similar level of those experienced after CWI. Although both treatments significantly reduced skin temperature, WBC elicited a greater decrease compared to CWI. These data may provide information to clinicians and researchers attempting to optimise WBC and CWI protocols in a clinical or sporting setting. PMID:23139763
Cold Water Mediates Greater Reductions in Limb Blood Flow than Whole Body Cryotherapy.

PubMed

Mawhinney, Chris; Low, David A; Jones, Helen; Green, Daniel J; Costello, Joseph T; Gregson, Warren

2017-06-01

Cold-water immersion (CWI) and whole body cryotherapy (WBC) are widely used recovery methods in an attempt to limit exercise-induced muscle damage, soreness, and functional deficits after strenuous exercise. The aim of this study was to compare the effects of ecologically valid CWI and WBC protocols on postexercise lower limb thermoregulatory, femoral artery, and cutaneous blood flow responses. Ten males completed a continuous cycle exercise protocol at 70% maximal oxygen uptake until a rectal temperature of 38°C was attained. Participants were then exposed to lower-body CWI (8°C) for 10 min, or WBC (-110°C) for 2 min, in a randomized crossover design. Rectal and thigh skin, deep, and superficial muscle temperatures, thigh, and calf skin blood flow (laser Doppler flowmetry), superficial femoral artery blood flow (duplex ultrasound), and arterial blood pressure were measured before, and for 40 min post, cooling interventions. Greater reductions in thigh skin (CWI, -5.9°C ± 1.8°C; WBC, 0.2°C ± 0.5°C; P < 0.001) and superficial (CWI, -4.4°C ± 1.3°C; WBC, -1.8°C ± 1.1°C; P < 0.001) and deep (CWI, -2.9°C ± 0.8°C; WBC, -1.3°C ± 0.6°C; P < 0.001) muscle temperatures occurred immediately after CWI. Decreases in femoral artery conductance were greater after CWI (CWI, -84% ± 11%; WBC, -59% ± 21%, P < 0.02) and thigh (CWI, -80% ± 5%; WBC, -59% ± 14%, P < 0.001), and calf (CWI, -73% ± 13%; WBC, -45% ± 17%, P < 0.001) cutaneous vasoconstriction was greater after CWI. Reductions in rectal temperature were similar between conditions after cooling (CWI, -0.6°C ± 0.4°C; WBC, -0.6°C ± 0.3°C; P = 0.98). Greater reductions in blood flow and tissue temperature were observed after CWI in comparison with WBC. These novel findings have practical and clinical implications for the use of cooling in the recovery from exercise and injury.
The effect of various cold-water immersion protocols on exercise-induced inflammatory response and functional recovery from high-intensity sprint exercise.

PubMed

White, Gillian E; Rhind, Shawn G; Wells, Greg D

2014-11-01

The purpose of this study was to investigate the effects of different cold-water immersion (CWI) protocols on the inflammatory response to and functional recovery from high-intensity exercise. Eight healthy recreationally active males completed five trials of a high-intensity intermittent sprint protocol followed by a randomly assigned recovery condition: 1 of 4 CWI protocols (CWI-10 min × 20 °C, CWI-30 min × 20 °C, CWI-10 min × 10 °C, or CWI-30 min × 10 °C) versus passive rest. Circulating mediators of the inflammatory response were measured from EDTA plasma taken pre-exercise (baseline), immediately post-exercise, and at 2, 24, and 48 h post-exercise. Ratings of perceived soreness and impairment were noted on a 10-pt Likert scale, and squat jump and drop jump were performed at these time points. IL-6, IL-8, and MPO increased significantly from baseline immediately post-exercise in all conditions. IL-6 remained elevated from baseline at 2 h in the CWI-30 min × 20 °C, CWI-10 min × 10 °C, and CWI-30 min × 10 °C conditions, while further increases were observed for IL-8 and MPO in the CWI-30 min × 20 °C and CWI-30 min × 10 °C conditions. Squat jump and drop jump height were significantly lower in all conditions immediately post-exercise and at 2 h. Drop jump remained below baseline at 24 and 48 h in the CON and CWI-10 min × 20 °C conditions only, while squat jump height returned to baseline in all conditions. Cold-water immersion appears to facilitate restoration of muscle performance in a stretch-shortening cycle, but not concentric power. These changes do not appear to be related to inflammatory modulation. CWI protocols of excessive duration may actually exacerbate the concentration of cytokines in circulation post-exercise; however, the origin of the circulating cytokines is not necessarily skeletal muscle.
Habituation of the cold shock response may include a significant perceptual component.

PubMed

Barwood, Martin J; Corbett, Jo; Wagstaff, Christopher R D

2014-02-01

Accidental immersion in cold water is a risk factor for many occupations. Habituation to cold-water immersion (CWI) is one practical means of reducing the cold shock response (CSR) on immersion. We investigated whether repeated thermoneutral water immersion (TWI) induced a perceptual habituation (i.e., could lessen perceived threat and anxiety) and consequently reduce the CSR on subsequent CWI. There were 12 subjects who completed seven 7-min head-out immersions. Immersions one and seven were CWls [15.0 (0.1) degrees C], and immersions two to six were TWI [34.9 (0.10) degrees C]. Anxiety 120-cm visual analogue scale) and the cardiorespiratory responses [heart rate (f(C)), respiratory frequency (f(R)), tidal volume (V(T)), and minute ventilation (V(E))] to immersion were measured throughout. Data were compared within subject between conditions using ANOVA to an alpha level of 0.05. Acute anxiety was significantly reduced after repeated exposure to the immersion scenario (i.e., TWI): CWI-1: 6.3 (4.4) cm; and CWI-2: 4.5 (4.0) cm [condition mean (SD)]. These differences did not influence the peak in the CSR. The f(C), f(R), and V(E) responses were similar between CWI-1 and CWI-2. V(T) response was significantly lower in CWI-2; mean (SD) across the immersion: CWI-1 1.27 (0.17) vs. CWI-2 1.11 0.21 L. Repeated TWI lessened the anxiety associated with CWI (perceptual habituation). This had a negligible effect on the primary components of the CSR, but did lower VT, which may reduce the volume of any aspirated water in an emergency situation. Reducing the threat appraisal of an environmental stressor may be a useful biproduct of survival training, thereby minimizing psychophysiological strain.
Does hydrotherapy help or hinder adaptation to training in competitive cyclists?

PubMed

Halson, Shona L; Bartram, Jason; West, Nicholas; Stephens, Jessica; Argus, Christos K; Driller, Matthew W; Sargent, Charli; Lastella, Michele; Hopkins, Will G; Martin, David T

2014-08-01

Cold water immersion (CWI) may be beneficial for acute recovery from exercise, but it may impair long-term performance by attenuating the stimuli responsible for adaptation to training. We compared effects of CWI and passive rest on cycling performance during a simulated cycling grand tour. Thirty-four male endurance-trained competitive cyclists were randomized to CWI for four times per week for 15 min at 15°C or control (passive recovery) groups for 7 d of baseline training, 21 d of intensified training, and an 11-d taper. Criteria for completion of training and testing were satisfied by 10 cyclists in the CWI group (maximal aerobic power, 5.13 ± 0.21 W·kg; mean ± SD) and 11 in the control group (5.01 ± 0.41 W·kg). Each week, cyclists completed a high-intensity interval cycling test and two 4-min bouts separated by 30 min. CWI was performed four times per week for 15 min at 15°C. Between baseline and taper, cyclists in the CWI group had an unclear change in overall 4-min power relative to control (2.7% ± 5.7%), although mean power in the second effort relative to the first was likely higher for the CWI group relative to control (3.0% ± 3.8%). The change in 1-s maximum mean sprint power in the CWI group was likely beneficial compared with control (4.4% ± 4.2%). Differences between groups for the 10-min time trial were unclear (-0.4% ± 4.3%). Although some effects of CWI on performance were unclear, data from this study do not support recent speculation that CWI is detrimental to performance after increased training load in competitive cyclists.

Comparing Laser Interferometry and Atom Interferometry Approaches to Space-Based Gravitational-Wave Measurement

NASA Technical Reports Server (NTRS)

Baker, John; Thorpe, Ira

2012-01-01

Thoroughly studied classic space-based gravitational-wave missions concepts such as the Laser Interferometer Space Antenna (LISA) are based on laser-interferometry techniques. Ongoing developments in atom-interferometry techniques have spurred recently proposed alternative mission concepts. These different approaches can be understood on a common footing. We present an comparative analysis of how each type of instrument responds to some of the noise sources which may limiting gravitational-wave mission concepts. Sensitivity to laser frequency instability is essentially the same for either approach. Spacecraft acceleration reference stability sensitivities are different, allowing smaller spacecraft separations in the atom interferometry approach, but acceleration noise requirements are nonetheless similar. Each approach has distinct additional measurement noise issues.
Physical and non-physical energy in scattered wave source-receiver interferometry.

PubMed

Meles, Giovanni Angelo; Curtis, Andrew

2013-06-01

Source-receiver interferometry allows Green's functions between sources and receivers to be estimated by means of convolution and cross-correlation of other wavefields. Source-receiver interferometry has been observed to work surprisingly well in practical applications when theoretical requirements (e.g., complete enclosing boundaries of other sources and receivers) are contravened: this paper contributes to explain why this may be true. Commonly used inter-receiver interferometry requires wavefields to be generated around specific stationary points in space which are controlled purely by medium heterogeneity and receiver locations. By contrast, application of source-receiver interferometry constructs at least kinematic information about physically scattered waves between a source and a receiver by cross-convolution of scattered waves propagating from and to any points on the boundary. This reduces the ambiguity in interpreting wavefields generated using source-receiver interferometry with only partial boundaries (as is standard in practical applications), as it allows spurious or non-physical energy in the constructed Green's function to be identified and ignored. Further, source-receiver interferometry (which includes a step of inter-receiver interferometry) turns all types of non-physical or spurious energy deriving from inter-receiver interferometry into what appears to be physical energy. This explains in part why source-receiver interferometry may perform relatively well compared to inter-receiver interferometry when constructing scattered wavefields.
What are the Physiological Mechanisms for Post-Exercise Cold Water Immersion in the Recovery from Prolonged Endurance and Intermittent Exercise?

PubMed

Ihsan, Mohammed; Watson, Greig; Abbiss, Chris R

2016-08-01

Intense training results in numerous physiological perturbations such as muscle damage, hyperthermia, dehydration and glycogen depletion. Insufficient/untimely restoration of these physiological alterations might result in sub-optimal performance during subsequent training sessions, while chronic imbalance between training stress and recovery might lead to overreaching or overtraining syndrome. The use of post-exercise cold water immersion (CWI) is gaining considerable popularity among athletes to minimize fatigue and accelerate post-exercise recovery. CWI, through its primary ability to decrease tissue temperature and blood flow, is purported to facilitate recovery by ameliorating hyperthermia and subsequent alterations to the central nervous system (CNS), reducing cardiovascular strain, removing accumulated muscle metabolic by-products, attenuating exercise-induced muscle damage (EIMD) and improving autonomic nervous system function. The current review aims to provide a comprehensive and detailed examination of the mechanisms underpinning acute and longer term recovery of exercise performance following post-exercise CWI. Understanding the mechanisms will aid practitioners in the application and optimisation of CWI strategies to suit specific recovery needs and consequently improve athletic performance. Much of the literature indicates that the dominant mechanism by which CWI facilitates short term recovery is via ameliorating hyperthermia and consequently CNS mediated fatigue and by reducing cardiovascular strain. In contrast, there is limited evidence to support that CWI might improve acute recovery by facilitating the removal of muscle metabolites. CWI has been shown to augment parasympathetic reactivation following exercise. While CWI-mediated parasympathetic reactivation seems detrimental to high-intensity exercise performance when performed shortly after, it has been shown to be associated with improved longer term physiological recovery and day to day training performances. The efficacy of CWI for attenuating the secondary effects of EIMD seems dependent on the mode of exercise utilised. For instance, CWI application seems to demonstrate limited recovery benefits when EIMD was induced by single-joint eccentrically biased contractions. In contrast, CWI seems more effective in ameliorating effects of EIMD induced by whole body prolonged endurance/intermittent based exercise modalities.
Optimizing Cold Water Immersion for Exercise-Induced Hyperthermia: A Meta-analysis.

PubMed

Zhang, Yang; Davis, Jon-Kyle; Casa, Douglas J; Bishop, Phillip A

2015-11-01

Cold water immersion (CWI) provides rapid cooling in events of exertional heat stroke. Optimal procedures for CWI in the field are not well established. This meta-analysis aimed to provide structured analysis of the effectiveness of CWI on the cooling rate in healthy adults subjected to exercise-induced hyperthermia. An electronic search (December 2014) was conducted using the PubMed and Web of Science. The mean difference of the cooling rate between CWI and passive recovery was calculated. Pooled analyses were based on a random-effects model. Sources of heterogeneity were identified through a mixed-effects model Q statistic. Inferential statistics aggregated the CWI cooling rate for extrapolation. Nineteen studies qualified for inclusion. Results demonstrate CWI elicited a significant effect: mean difference, 0.03°C·min(-1); 95% confidence interval, 0.03-0.04°C·min(-1). A conservative, observed estimate of the CWI cooling rate was 0.08°C·min(-1) across various conditions. CWI cooled individuals twice as fast as passive recovery. Subgroup analyses revealed that cooling was more effective (Q test P < 0.10) when preimmersion core temperature ≥38.6°C, immersion water temperature ≤10°C, ambient temperature ≥20°C, immersion duration ≤10 min, and using torso plus limbs immersion. There is insufficient evidence of effect using forearms/hands CWI for rapid cooling: mean difference, 0.01°C·min(-1); 95% confidence interval, -0.01°C·min(-1) to 0.04°C·min(-1). A combined data summary, pertaining to 607 subjects from 29 relevant studies, was presented for referencing the weighted cooling rate and recovery time, aiming for practitioners to better plan emergency procedures. An optimal procedure for yielding high cooling rates is proposed. Using prompt vigorous CWI should be encouraged for treating exercise-induced hyperthermia whenever possible, using cold water temperature (approximately 10°C) and maximizing body surface contact (whole-body immersion).
Cold water immersion enhances recovery of submaximal muscle function after resistance exercise.

PubMed

Roberts, Llion A; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

2014-10-15

We investigated the effect of cold water immersion (CWI) on the recovery of muscle function and physiological responses after high-intensity resistance exercise. Using a randomized, cross-over design, 10 physically active men performed high-intensity resistance exercise followed by one of two recovery interventions: 1) 10 min of CWI at 10°C or 2) 10 min of active recovery (low-intensity cycling). After the recovery interventions, maximal muscle function was assessed after 2 and 4 h by measuring jump height and isometric squat strength. Submaximal muscle function was assessed after 6 h by measuring the average load lifted during 6 sets of 10 squats at 80% of 1 repetition maximum. Intramuscular temperature (1 cm) was also recorded, and venous blood samples were analyzed for markers of metabolism, vasoconstriction, and muscle damage. CWI did not enhance recovery of maximal muscle function. However, during the final three sets of the submaximal muscle function test, participants lifted a greater load (P < 0.05, Cohen's effect size: 1.3, 38%) after CWI compared with active recovery. During CWI, muscle temperature decreased ∼7°C below postexercise values and remained below preexercise values for another 35 min. Venous blood O2 saturation decreased below preexercise values for 1.5 h after CWI. Serum endothelin-1 concentration did not change after CWI, whereas it decreased after active recovery. Plasma myoglobin concentration was lower, whereas plasma IL-6 concentration was higher after CWI compared with active recovery. These results suggest that CWI after resistance exercise allows athletes to complete more work during subsequent training sessions, which could enhance long-term training adaptations. Copyright © 2014 the American Physiological Society.
Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training.

PubMed

Roberts, Llion A; Raastad, Truls; Markworth, James F; Figueiredo, Vandre C; Egner, Ingrid M; Shield, Anthony; Cameron-Smith, David; Coombes, Jeff S; Peake, Jonathan M

2015-09-15

We investigated functional, morphological and molecular adaptations to strength training exercise and cold water immersion (CWI) through two separate studies. In one study, 21 physically active men strength trained for 12 weeks (2 days per week), with either 10 min of CWI or active recovery (ACT) after each training session. Strength and muscle mass increased more in the ACT group than in the CWI group (P < 0.05). Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P < 0.05), but not the CWI group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed by CWI or ACT. Muscle biopsies were collected before and 2, 24 and 48 h after exercise. The number of satellite cells expressing neural cell adhesion molecule (NCAM) (10-30%) and paired box protein (Pax7) (20-50%) increased 24-48 h after exercise with ACT. The number of NCAM(+) satellite cells increased 48 h after exercise with CWI. NCAM(+) - and Pax7(+) -positive satellite cell numbers were greater after ACT than after CWI (P < 0.05). Phosphorylation of p70S6 kinase(Thr421/Ser424) increased after exercise in both conditions but was greater after ACT (P < 0.05). These data suggest that CWI attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.
"Float first and kick for your life": Psychophysiological basis for safety behaviour on accidental short-term cold water immersion.

PubMed

Barwood, Martin J; Burrows, Holly; Cessford, Jess; Goodall, Stuart

2016-02-01

Accidental cold-water immersion (CWI) evokes the life threatening cold shock response (CSR) which increases the risk of drowning. Consequently, the safety behaviour selected is critical in determining survival; the present advice is to 'float first' and remain stationary (i.e. rest). We examined whether leg only exercise (i.e., treading water; 'CWI-Kick') immediately on CWI could reduce the symptoms of the CSR, offset the reduction in cerebral blood flow that is known to occur and reduce the CSR's symptoms of breathlessness. We also examined whether perceptual responses instinctive to accidental CWI were exacerbated by this alternative behaviour. We contrasted CWI-Kick to a 'CWI-Rest' condition and a thermoneutral control (35°C); 'TN-Rest'. Seventeen participants were tested (9 males, 8 females). All immersions were standardised; water temperature in cold conditions (i.e., 12°C) was matched ±/0.5°C within participant. Middle cerebral artery blood flow velocity (MCAv) and cardiorespiratory responses were measured along with thermal perception (sensation and comfort) and dyspnoea. Data were analysed using repeated measures ANOVA (alpha level of 0.05). MCAv was significantly reduced in CWI-Rest (-6 (9)%; 1st minute of immersion) but was offset by leg only exercise immediately on cold water entry; CWI-Kick MCAv was never different to TN-Rest (-3 (16)% cf. 5 (4)%). All CWI cardiorespiratory and perceptual responses were different to TN-Rest but were not exacerbated by leg only exercise. Treading water may aid survival by offsetting the reduction in brain blood flow velocity without changing the instinctive behavioural response (i.e. perceptions). "Float first - and kick for your life" would be a suitable amendment to the water safety advice. Copyright © 2015 Elsevier Inc. All rights reserved.
Comparative study of stability of soluble and cell wall invertase from Saccharomyces cerevisiae.

PubMed

Margetić, Aleksandra; Vujčić, Zoran

2017-03-16

Yeast Saccharomyces cerevisiae is the most significant source of enzyme invertase. It is mainly used in the food industry as a soluble or immobilized enzyme. The greatest amount of invertase is located in the periplasmic space in yeast. In this work, it was isolated into two forms of enzyme from yeast S. cerevisiae cell, soluble and cell wall invertase (CWI). Both forms of enzyme showed same temperature optimum (60°C), similar pH optimum, and kinetic parameters. The significant difference between these biocatalysts was observed in their thermal stability, stability in urea and methanol solution. At 60°C, CWI had 1.7 times longer half-life than soluble enzyme, while at 70°C CWI showed 8.7 times longer half-life than soluble enzyme. After 2-hr of incubation in 8 M urea solution, soluble invertase and CWI retained 10 and 60% of its initial activity, respectively. During 22 hr of incubation of both enzymes in 30 and 40% methanol, soluble invertase was completely inactivated, while CWI changed its activity within the experimental error. Therefore, soluble invertase and CWI have not shown any substantial difference, but CWI showed better thermal stability and stability in some of the typical protein-denaturing agents.
5000 Meter Run Performance is not Enhanced 24 Hrs After an Intense Exercise Bout and Cold Water Immersion.

PubMed

Stenson, Mary C; Stenson, Matthew R; Matthews, Tracey D; Paolone, Vincent J

2017-06-01

Cold water immersion (CWI) is used by endurance athletes to speed recovery between exercise bouts, but little evidence is available on the effects of CWI on subsequent endurance performance. The purpose of this study was to investigate the effects of CWI following an acute bout of interval training on 5000 m run performance 24 hrs after interval training, perceived muscle soreness (PMS), range of motion (ROM), thigh circumference (TC), and perceived exertion (RPE). Nine endurance-trained males completed 2 trials, each consisting of an interval training session of 8 repetitions of 1200 m at a running pace equal to 75% of VO 2 peak, either a control or CWI treatment, and a timed 5000 m run 24 hrs post interval training session. CWI was performed for 12 min at 12 degrees Celsius on the legs. Recovery treatments were performed in a counterbalanced design. Run time for 5000 m was not different between the CWI and control trials (CWI = 1317.33 ± 128.33 sec, control = 1303.44 ± 105.53 sec; p = 0.48). PMS increased significantly from baseline to immediately post exercise (BL = 1.17 ± 0.22, POST = 2.81 ± 0.52; p = 0.02) and remained elevated from baseline to 24 hrs post exercise (POST24 = 2.19 ± 0.32; p = 0.02), but no difference was observed between the treatments. No differences were observed for the interaction between time and treatment for TC (λ = 0.73, p = 0.15) and ROM (λ = 0.49; p = 0.10). CWI performed immediately following an interval training exercise bout did not enhance subsequent 5000 m run performance or reduce PMS. CWI may not provide a recovery or performance advantage when athletes are accustomed to the demands of the prior exercise bout.
Dosages of cold-water immersion post exercise on functional and clinical responses: a randomized controlled trial.

PubMed

Machado, A F; Almeida, A C; Micheletti, J K; Vanderlei, F M; Tribst, M F; Netto Junior, J; Pastre, C M

2017-11-01

Cold-water immersion (CWI) is one of the recovery techniques commonly used by athletes for post-exercise recovery. Nevertheless, the effects of CWI using different temperatures and the dose-response relationship of this technique have not yet been investigated. The aims of this study were to compare the effects of two strategies of CWI, using different water temperatures with passive recovery post exercise in the management of some markers of muscle damage, and to observe whether any of the techniques used caused deleterious effects on performance. Sixty healthy male participants performed an eccentric protocol to induce muscle damage and were then randomized to one of three groups (CWI1: 15 min at 9 °C; CWI2: 15 min at 14 °C; CG: control group). Levels of creatine kinase, muscle soreness, pain threshold, perception of recovery, and maximal voluntary isometric contraction were monitored up to 96 h post exercise. A large effect for time for all outcomes was observed [P < 0.001; CK (ES = 0.516), muscle soreness (ES = 0.368); pain threshold (ES = 0.184); perception of recovery (ES = 0.565); MVIC (ES = 0.273)]. CWI groups presented an earlier recovery for muscle soreness with lower ratings immediately post recovery. For delayed effects, the application of CWI2 (15 min at 14 °C) presented earlier recovery compared with CWI1 and control condition for maximal voluntary isometric contraction (P < 0.05). There were no significant group and interaction (Group × Time) effects. CWI groups acted more efficiently for muscle soreness and performance considering the time of recovery was observed. No evidence was found to suggest dose-response relationship and deleterious effects. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Interferometry

NASA Technical Reports Server (NTRS)

Ridgway, Stephen; Wilson, Robert W.; Begelman, Mitchell C.; Bender, Peter; Burke, Bernard F.; Cornwell, Tim; Drever, Ronald; Dyck, H. Melvin; Johnston, Kenneth J.; Kibblewhite, Edward

1991-01-01

The following recommended programs are reviewed: (1) infrared and optical interferometry (a ground-based and space programs); (2) compensation for the atmosphere with adaptive optics (a program for development and implementation of adaptive optics); and (3) gravitational waves (high frequency gravitational wave sources (LIGO), low frequency gravitational wave sources (LAGOS), a gravitational wave observatory program, laser gravitational wave observatory in space, and technology development during the 1990's). Prospects for international collaboration and related issues are also discussed.
Effect of evening postexercise cold water immersion on subsequent sleep.

PubMed

Robey, Elisa; Dawson, Brian; Halson, Shona; Gregson, Warren; King, Stuart; Goodman, Carmel; Eastwood, Peter

2013-07-01

This study investigated the effect of cold water immersion after evening exercise on subsequent sleep quality and quantity in trained cyclists. In the evenings (~1900 h) on three separate occasions, male cyclists (n = 11) underwent either no exercise (control, CON), exercise only (EX), or exercise followed by cold water immersion (CWI). EX comprised cycling for 15 min at 75% peak power, then a 15-min maximal time trial. After each condition, a full laboratory-based sleep study (polysomnography) was performed. Core and skin temperature, heart rate, salivary melatonin, ratings of perceived fatigue, and recovery were measured in each trial. No differences were observed between conditions for any whole night sleep measures, including total sleep time, sleep efficiency, sleep onset latency, rapid eye movement onset latency, wake after sleep onset, or proportion of the night spent in different sleep stages. Core temperature in EX and CWI trials was higher than CON, until it decreased below that of EX and CON until bedtime in CWI. After bedtime, core temperature was similar for all conditions throughout the night, except for a 90-min period where it was lower for CWI than EX and CON (3.5-4.5 h postexercise). Heart rates for EX and CWI were both significantly higher than CON postexercise until bedtime, whereas skin temperature after CWI was significantly lower than EX and CON, remaining lower than EX until 3 h postexercise. Melatonin levels and recovery ratings were similar between conditions. Fatigue ratings were significantly elevated after exercise in both CWI and EX conditions, with EX still being elevated compared with CON at bedtime. Whole night sleep architecture is not affected by evening exercise alone or when followed by CWI.
β-Hydroxy-β-methylbutyrate (HMB)-free acid attenuates circulating TNF-α and TNFR1 expression postresistance exercise.

PubMed

Townsend, Jeremy R; Fragala, Maren S; Jajtner, Adam R; Gonzalez, Adam M; Wells, Adam J; Mangine, Gerald T; Robinson, Edward H; McCormack, William P; Beyer, Kyle S; Pruna, Gabriel J; Boone, Carleigh H; Scanlon, Tyler M; Bohner, Jonathan D; Stout, Jeffrey R; Hoffman, Jay R

2013-10-15

The purpose of this study was to examine the effect of β-hydroxy-β-methylbutyrate-free acid (HMB-FA) and cold-water immersion (CWI) on circulating concentrations of TNF-α and monocyte TNF-α receptor 1 (TNFR1) expression. Forty resistance-trained men (22.3 ± 2.4 yr) were randomized into four groups [placebo (PL), HMB-FA, CWI, and HMB-FA-CWI] and performed an acute, intense exercise protocol (four sets of up to 10 repetitions of the squat, dead lift, and split squat). Participants also performed four sets of up to 10 repetitions of the squat at 24 and 48 h following the initial exercise bout. Blood was sampled before exercise (PRE), immediately postexercise (IP), and 30 min, 24 h, and 48 h postexercise (30P, 24P, and 48P, respectively). Circulating TNF-α was assayed, and TNFR1 expression on CD14+ monocytes was measured by flow cytometry. The exercise protocol significantly elevated TNF-α in only PL (P = 0.006) and CWI (P = 0.045) IP. Mean percent changes show that TNF-α significantly increased from PRE to IP for only PL and CWI groups (P < 0.05), whereas the percent change of TNF-α for HMB-FA and HMB-FA-CWI was not significant. TNFR1 expression was elevated in PL (P = 0.023) and CWI (P = 0.02) at 30P compared with PRE, whereas both HMB-FA-treated groups did not increase significantly. In conclusion, HMB-FA attenuated circulating TNF-α IP and TNFR1 expression during recovery compared with PL and CWI. HMB-FA supplementation may attenuate the initial immune response to intense exercise, which may reduce recovery time following intense exercise.
Cost-effectiveness analysis comparing epidural, patient-controlled intravenous morphine, and continuous wound infiltration for postoperative pain management after open abdominal surgery.

PubMed

Tilleul, P; Aissou, M; Bocquet, F; Thiriat, N; le Grelle, O; Burke, M J; Hutton, J; Beaussier, M

2012-06-01

Continuous wound infiltration (CWI), i.v. patient-controlled analgesia (i.v.-PCA), and epidural analgesia (EDA) are analgesic techniques commonly used for pain relief after open abdominal surgery. The aim of this study was to evaluate the cost-effectiveness of these techniques. A decision analytic model was developed, including values retrieved from clinical trials and from an observational prospective cohort of 85 patients. Efficacy criteria were based on pain at rest (VAS ≤ 30/100 mm at 24 h). Resource use and costs were evaluated from medical record measurements and published data. Probabilistic sensitivity analysis (PSA) was performed. When taking into account all resources consumed, the CWI arm (€ 6460) is economically dominant when compared with i.v.-PCA (€ 7273) and EDA (€ 7500). The proportion of patients successfully controlled for their postoperative pain management are 77.4%, 53.9%, and 72.9% for CWI, i.v.-PCA, and EDA, respectively, demonstrating the CWI procedure to be both economically and clinically dominant. PSA reported that CWI remains cost saving in 70.4% of cases in comparison with EDA and in 59.2% of cases when compared with PCA. Device-related costs of using CWI for pain management after abdominal laparotomy are partly counterbalanced by a reduction in resource consumption. The cost-effectiveness analysis suggests that CWI is the dominant treatment strategy for managing postoperative pain (i.e. more effective and less costly) in comparison with i.v.-PCA. When compared with EDA, CWI is less costly with almost equivalent efficacy. This economic evaluation may be useful for clinicians to design algorithms for pain management after major abdominal surgery.
Cold water immersion recovery after simulated collision sport exercise.

PubMed

Pointon, Monique; Duffield, Rob

2012-02-01

This investigation examined the effects of cold water immersion (CWI) recovery after simulated collision sport exercise. Ten male rugby athletes performed three sessions consisting of a 2 × 30-min intermittent-sprint exercise (ISE) protocol with either tackling (T) or no tackling (CONT), followed by a 20-min CWI intervention (TCWI) or passive recovery (TPASS and CONT) in a randomized order. The ISE consisted of a 15-m sprint every minute separated by self-paced bouts of hard running, jogging, and walking for the remainder of the minute. Every sixth rotation, participants performed 5 × 10-m runs, receiving a shoulder-led tackle to the lower body on each effort. Sprint time and distance covered during ISE were recorded, with voluntary (maximal voluntary contraction; MVC) and evoked neuromuscular function (voluntary activation; VA), electromyogram (root mean square (RMS)), ratings of perceived muscle soreness (MS), capillary and venous blood markers for metabolites and muscle damage, respectively measured before and after exercise, immediately after recovery, and 2 and 24 h after recovery. Total distance covered during exercise was significantly greater in CONT (P = 0.01), without differences between TPASS and TCWI (P > 0.05). TCWI resulted in increased MVC, VA, and RMS immediately after recovery (P < 0.05). M-wave amplitude and peak twitch were significantly increased after recovery and 2 h after recovery, respectively, in TCWI (P < 0.05). Although TCWI had no effect on the elevation in blood markers for muscle damage (P > 0.05), lactate was significantly reduced after recovery compared with TPASS (P = 0.04). CWI also resulted in reduced MS 2 h after recovery compared with TPASS (P < 0.05). The introduction of body contact reduces exercise performance, whereas the use of CWI results in a faster recovery of MVC, VA, and RMS and improves muscle contractile properties and perceptions of soreness after collision-based exercise.
Effect of short-term cold-water immersion on muscle pain sensitivity in elite track cyclists.

PubMed

Klich, Sebastian; Krymski, Igor; Michalik, Kamil; Kawczyński, Adam

2018-05-01

To determine the effect of short-term cold-water immersion (CWI) on muscle pain sensitivity after maximal anaerobic power training in track cyclists. Repeated measures. University Laboratory. 12 elite sprint track cyclists (age 24,75 ± 4,23 years). PPT measurements were made on dominant lower extremity (right) in 20 reference points, including anterior thigh muscles, posterior thigh muscles and posterior cuff muscles. PPT levels were measured: 1) before workout, 2) immediately after workout, but before CWI 3) 1 h after CWI and 4) 12 h after CWI. Mean PPT values for each muscle group per participant were calculated for further statistical analysis. The average PPT for anterior thigh muscles decreased significantly after effort (p = 0.001) and increased significantly 1 h after CWI (p = 0.048). In posterior thigh muscles PPT decreased significantly after effort (p = 0.014) and increased significantly 1 h and 12 h after CWI (p = 0.045 and p = 0.25 respectively). However, in posterior cuff muscles PPT decreased only after effort (p = 0.001). Short-term repeated sprint exercise appears to affect PPT in track cyclists. This study have reported that CWI in 5 °C for 5 min have had a beneficial effect in minimizing PPT 1 h post repeated maximal sprint training. Copyright © 2018 Elsevier Ltd. All rights reserved.
Recovery From Exercise-Induced Muscle Damage: Cold-Water Immersion Versus Whole-Body Cryotherapy.

PubMed

Abaïdia, Abd-Elbasset; Lamblin, Julien; Delecroix, Barthélémy; Leduc, Cédric; McCall, Alan; Nédélec, Mathieu; Dawson, Brian; Baquet, Georges; Dupont, Grégory

2017-03-01

To compare the effects of cold-water immersion (CWI) and whole-body cryotherapy (WBC) on recovery kinetics after exercise-induced muscle damage. Ten physically active men performed single-leg hamstring eccentric exercise comprising 5 sets of 15 repetitions. Immediately postexercise, subjects were exposed in a randomized crossover design to CWI (10 min at 10°C) or WBC (3 min at -110°C) recovery. Creatine kinase concentrations, knee-flexor eccentric (60°/s) and posterior lower-limb isometric (60°) strength, single-leg and 2-leg countermovement jumps, muscle soreness, and perception of recovery were measured. The tests were performed before and immediately, 24, 48, and 72 h after exercise. Results showed a very likely moderate effect in favor of CWI for single-leg (effect size [ES] = 0.63; 90% confidence interval [CI] = -0.13 to 1.38) and 2-leg countermovement jump (ES = 0.68; 90% CI = -0.08 to 1.43) 72 h after exercise. Soreness was moderately lower 48 h after exercise after CWI (ES = -0.68; 90% CI = -1.44 to 0.07). Perception of recovery was moderately enhanced 24 h after exercise for CWI (ES = -0.62; 90% CI = -1.38 to 0.13). Trivial and small effects of condition were found for the other outcomes. CWI was more effective than WBC in accelerating recovery kinetics for countermovement-jump performance at 72 h postexercise. CWI also demonstrated lower soreness and higher perceived recovery levels across 24-48 h postexercise.
Effects of cold water immersion and active recovery on post-exercise heart rate variability.

PubMed

Bastos, F N; Vanderlei, L C M; Nakamura, F Y; Bertollo, M; Godoy, M F; Hoshi, R A; Junior, J N; Pastre, C M

2012-11-01

The aim of the present study was to investigate the potential benefits of cold water immersion (CWI) and active recovery (AR) on blood lactate concentration ([Lac]) and heart rate variability (HRV) indices following high-intensity exercise. 20 male subjects were recruited. On the first visit, an incremental test was performed to determine maximal oxygen consumption and the associated speed (MAS). The remaining 3 visits for the performance of constant velocity exhaustive tests at MAS and different recovery methods (6 min) were separated by 7-day intervals [randomized: CWI, AR or passive recovery (PR)]. The CWI and AR lowered [Lac] (p<0.05) at 11, 13 and 15 min after exercise cessation in comparison to PR. There was a 'time' and 'recovery mode' interaction for 2 HRV indices: standard deviation of normal R-R intervals (SDNN) (partial eta squared=0.114) and natural log of low-frequency power density (lnLF) (partial eta squared=0.090). CWI presented significantly higher SDNN compared to PR at 15 min of recovery (p<0.05). In addition, greater SDNN values were found in CWI vs. AR during the application of recovery interventions, and at 30 and 75 min post-exercise (p<0.05 for all differences). The lnLF during the recovery interventions and at 75 min post-exercise was greater using CWI compared with AR (p<0.05). For square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) and natural log of high-frequency power density (lnHF), a moderate effect size was found between CWI and PR during the recovery interventions and at 15 min post-exercise. Our findings show that AR and CWI offer benefits regarding the removal of [Lac] following high-intensity exercise. While limited, CWI results in some improvement in post-exercise cardiac autonomic regulation compared to AR and PR. Further, AR is not recommended if the aim is to accelerate the parasympathetic reactivation. © Georg Thieme Verlag KG Stuttgart · New York.
Effects of cold water immersion and active recovery on hemodynamics and recovery of muscle strength following resistance exercise.

PubMed

Roberts, Llion A; Muthalib, Makii; Stanley, Jamie; Lichtwark, Glen; Nosaka, Kazunori; Coombes, Jeff S; Peake, Jonathan M

2015-08-15

Cold water immersion (CWI) and active recovery (ACT) are frequently used as postexercise recovery strategies. However, the physiological effects of CWI and ACT after resistance exercise are not well characterized. We examined the effects of CWI and ACT on cardiac output (Q̇), muscle oxygenation (SmO2), blood volume (tHb), muscle temperature (Tmuscle), and isometric strength after resistance exercise. On separate days, 10 men performed resistance exercise, followed by 10 min CWI at 10°C or 10 min ACT (low-intensity cycling). Q̇ (7.9 ± 2.7 l) and Tmuscle (2.2 ± 0.8°C) increased, whereas SmO2 (-21.5 ± 8.8%) and tHb (-10.1 ± 7.7 μM) decreased after exercise (P < 0.05). During CWI, Q̇ (-1.1 ± 0.7 l) and Tmuscle (-6.6 ± 5.3°C) decreased, while tHb (121 ± 77 μM) increased (P < 0.05). In the hour after CWI, Q̇ and Tmuscle remained low, while tHb also decreased (P < 0.05). By contrast, during ACT, Q̇ (3.9 ± 2.3 l), Tmuscle (2.2 ± 0.5°C), SmO2 (17.1 ± 5.7%), and tHb (91 ± 66 μM) all increased (P < 0.05). In the hour after ACT, Tmuscle, and tHb remained high (P < 0.05). Peak isometric strength during 10-s maximum voluntary contractions (MVCs) did not change significantly after CWI, whereas it decreased after ACT (-30 to -45 Nm; P < 0.05). Muscle deoxygenation time during MVCs increased after ACT (P < 0.05), but not after CWI. Muscle reoxygenation time after MVCs tended to increase after CWI (P = 0.052). These findings suggest first that hemodynamics and muscle temperature after resistance exercise are dependent on ambient temperature and metabolic demands with skeletal muscle, and second, that recovery of strength after resistance exercise is independent of changes in hemodynamics and muscle temperature. Copyright © 2015 the American Physiological Society.
Parsimonious surface wave interferometry

NASA Astrophysics Data System (ADS)

Li, Jing; Hanafy, Sherif; Schuster, Gerard T.

2018-03-01

To decrease the recording time of a 2-D seismic survey from a few days to one hour or less, we present a parsimonious surface wave interferometry method. Interferometry allows for the creation of a large number of virtual shot gathers from just two reciprocal shot gathers by crosscoherence of trace pairs. Then, the virtual surface waves can be inverted for the S-wave velocity model by wave-equation dispersion inversion (WD). Synthetic and field data tests suggest that parsimonious WD (PWD) gives S-velocity tomograms that are comparable to those obtained from a conventional survey with a shot at each receiver. The limitation of PWD is that the virtual data lose some information so that the resolution of the S-velocity tomogram can be modestly lower than that of the S-velocity tomogram inverted from a conventional survey.

Effective Algorithm for Detection and Correction of the Wave Reconstruction Errors Caused by the Tilt of Reference Wave in Phase-shifting Interferometry

NASA Astrophysics Data System (ADS)

Xu, Xianfeng; Cai, Luzhong; Li, Dailin; Mao, Jieying

2010-04-01

In phase-shifting interferometry (PSI) the reference wave is usually supposed to be an on-axis plane wave. But in practice a slight tilt of reference wave often occurs, and this tilt will introduce unexpected errors of the reconstructed object wave-front. Usually the least-square method with iterations, which is time consuming, is employed to analyze the phase errors caused by the tilt of reference wave. Here a simple effective algorithm is suggested to detect and then correct this kind of errors. In this method, only some simple mathematic operation is used, avoiding using least-square equations as needed in most methods reported before. It can be used for generalized phase-shifting interferometry with two or more frames for both smooth and diffusing objects, and the excellent performance has been verified by computer simulations. The numerical simulations show that the wave reconstruction errors can be reduced by 2 orders of magnitude.
Simultaneous Dual Species Matter Wave Interferometry

NASA Astrophysics Data System (ADS)

Schlippert, Dennis; Albers, Henning; Richardson, Logan; Meiners, Christian; Hartwig, Jonas; Ertmer, Wolfgang; Rasel, Ernst

2014-05-01

We report on the first realization of a simultaneous 39K-87Rb-dual species matter wave interferometer measuring gravitational acceleration with the aim to test Einstein's Equivalence Principle (EEP). Compared to classical tests such as torsion pendulum experiments and Lunar Laser Ranging, chemical elements suitable for performing matter wave interferometry can provide complementary information. We show the performance of our apparatus and discuss current limitations and future improvements towards highly sensitive matter wave tests of EEP.
Application of deconvolution interferometry with both Hi-net and KiK-net data

NASA Astrophysics Data System (ADS)

Nakata, N.

2013-12-01

Application of deconvolution interferometry to wavefields observed by KiK-net, a strong-motion recording network in Japan, is useful for estimating wave velocities and S-wave splitting in the near surface. Using this technique, for example, Nakata and Snieder (2011, 2012) found changed in velocities caused by Tohoku-Oki earthquake in Japan. At the location of the borehole accelerometer of each KiK-net station, a velocity sensor is also installed as a part of a high-sensitivity seismograph network (Hi-net). I present a technique that uses both Hi-net and KiK-net records for computing deconvolution interferometry. The deconvolved waveform obtained from the combination of Hi-net and KiK-net data is similar to the waveform computed from KiK-net data only, which indicates that one can use Hi-net wavefields for deconvolution interferometry. Because Hi-net records have a high signal-to-noise ratio (S/N) and high dynamic resolution, the S/N and the quality of amplitude and phase of deconvolved waveforms can be improved with Hi-net data. These advantages are especially important for short-time moving-window seismic interferometry and deconvolution interferometry using later coda waves.
Modeling of Compaction Wave Behavior in Confined Granular Energetic Material

DTIC Science & Technology

1990-08-01

Compacted 65% TMD Aggregate Melamine Compaction Wave Microwave DIAGNOSTICS: Interferometry (a) Microwave Interferometry (b) 3 Wall-Mounted Pressure...involved 65% TMD melamine but was run very recently (Dec 1989) The value of compaction wave speed (from the microwave data) just after impact is...47 B. Simulation of PDC-M34 / 65% TMD Melamine (Inert Material) ........ 54 C. Influence of Energy Release / PDC Experiment
Water immersion in the treatment of exertional hyperthermia: physical determinants.

PubMed

Friesen, Brian J; Carter, Mike R; Poirier, Martin P; Kenny, Glen P

2014-09-01

We examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (CWI, 2°C) and temperate water immersion (TWI, 26°C) after exercise-induced hyperthermia. Twenty male participants were divided into two groups: high (315.6 ± 7.9 cm·kg, n = 10) and low (275.6 ± 8.6 cm·kg, n = 10) AD/LBM. On two separate occasions, participants ran on a treadmill in the heat (40.0°C, 20% relative humidity) wearing an impermeable rain suit until rectal temperature reached 40.0°C. After exercise, participants were immersed up to the nipples (arms remained out of the water) in either a CWI (2°C) or a TWI (26°C) circulated water bath until rectal temperature returned to 37.5°C. Overall rectal cooling rates were significantly different between experimental groups (high vs low AD/LBM, P = 0.005) and between immersion conditions (CWI vs TWI, P < 0.001). Individuals with a high AD/LBM had an approximately 1.7-fold greater overall rectal cooling rate relative to those with low AD/LBM during both CWI (high: 0.27°C·min ± 0.10°C·min vs low: 0.16°C·min ± 0.10°C·min) and TWI (high: 0.10°C·min ± 0.05°C·min vs low: 0.06°C·min ± 0.02°C·min). Further, the overall rectal cooling rates during CWI were approximately 2.7-fold greater than during TWI for both the high (CWI: 0.27°C·min ± 0.10°C·min vs TWI: 0.10°C·min ± 0.05°C·min) and the low (CWI: 0.16°C·min ± 0.10°C·min vs TWI: 0.06°C·min ± 0.02°C·min) AD/LBM groups. We show that individuals with a low AD/LBM have a reduced rectal cooling rate and take longer to cool than those with a high AD/LBM during both CWI and TWI. However, CWI provides the most effective cooling treatment irrespective of physical differences.
The Cell Wall Integrity Signaling Pathway and Its Involvement in Secondary Metabolite Production.

PubMed

Valiante, Vito

2017-12-06

The fungal cell wall is the external and first layer that fungi use to interact with the environment. Every stress signal, before being translated into an appropriate stress response, needs to overtake this layer. Many signaling pathways are involved in translating stress signals, but the cell wall integrity (CWI) signaling pathway is the one responsible for the maintenance and biosynthesis of the fungal cell wall. In fungi, the CWI signal is composed of a mitogen-activated protein kinase (MAPK) module. After the start of the phosphorylation cascade, the CWI signal induces the expression of cell-wall-related genes. However, the function of the CWI signal is not merely the activation of cell wall biosynthesis, but also the regulation of expression and production of specific molecules that are used by fungi to better compete in the environment. These molecules are normally defined as secondary metabolites or natural products. This review is focused on secondary metabolites affected by the CWI signal pathway with a special focus on relevant natural products such as melanins, mycotoxins, and antibacterial compounds.
Atom Interferometry for Detection of Gravitational Waves: Progress and Prospects

NASA Astrophysics Data System (ADS)

Hogan, Jason

2015-04-01

Gravitational wave astronomy promises to provide a new window into the universe, collecting information about astrophysical systems and cosmology that is difficult or impossible to acquire by other methods. Detector designs based on atom interferometry offer a number of advantages over traditional approaches, including access to conventionally inaccessible frequency ranges and substantially reduced antenna baselines. Atomic physics techniques also make it possible to build a gravitational wave detector with a single linear baseline, potentially offering advantages in cost and design flexibility. In support of these proposals, recent progress in long baseline atom interferometry has enabled observation of matter wave interference with atomic wavepacket separations exceeding 10 cm and interferometer durations of more than 2 seconds. These results are obtained in a 10-meter drop tower incorporating large momentum transfer atom optics. This approach can provide ground-based proof-of-concept demonstrations of many of the technical requirements of both terrestrial and satellite gravitational wave detectors.
Processing and interpretation of experiments in the microwave interferometry of shock waves in a weakly ionized plasma

NASA Astrophysics Data System (ADS)

Ershov, A. P.; Klishin, S. V.; Kuzovnikov, S. V.; Ponomareva, S. E.; Pyt'ev, Iu. P.

1990-12-01

The reduction method is applied to the microwave interferometry of shock waves in a weakly ionized plasma, making it possible to improve the spatial resolution of the instrument. It is shown experimentally that the structure of the shock wave electron component in a high-frequency discharge plasma in atomic and molecular gases is characterized by the presence of a precursor in the form of a rarefaction wave. The origin of the precursor is examined.
Laser Development for Gravitational-Wave Interferometry in Space

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan

2012-01-01

We are reporting on our development work on laser (master oscillator) and optical amplifier systems for gravitational-wave interferometry in space. Our system is based on the mature, wave-guided optics technologies, which have advantages over bulk, crystal-based, free-space optics. We are investing in a new type of compact, low-noise master oscillator, called the planar-waveguide external cavity diode laser. We made measurements, including those of noise, and performed space-qualification tests.
Metabolic gene products have evolved to interact with the cell wall integrity pathway in Saccharomyces cerevisiae.

PubMed

Ugbogu, Eziuche A; Wang, Ke; Schweizer, Lilian M; Schweizer, Michael

2016-12-01

Two of the five unlinked genes theoretically capable of encoding 5-phosphoribosyl-1(α)-pyrophosphate (PRPP) synthetase (Prs) in Saccharomyces cerevisiae, PRS1 and PRS5, contain in-frame insertions which separate the cation- and PRPP-binding sites, diagnostic of Prs polypeptides. The impairment of cell wall integrity (CWI) mitogen-activated protein kinase (MAPK) cascade in strains lacking PRS1 and the synthetic lethality associated with loss of PRS1 and PRS5 imply that these insertions are not gratuitous. Coimmunoprecipitation revealed that Prs1 interacts with the CWI MAPK pathway, only when Slt2 has been phosphorylated by Mkk1/2. Three serine residues identified by phosphoproteome analysis (Ficarro et al 2002) are located in one of the insertions of PRS5 thereby defining Prs5 as one of the 11 triply phosphorylated proteins in yeast. Mutation of these phosphosites compromised the transcriptional readout of one endpoint of the CWI pathway, Rlm1, as well as the expression of the gene encoding the stress-activated 1,3 β-glucan synthase, Fks2, regulated by a second endpoint of the CWI pathway, Swi4/Swi6 (SBF transcription factor). Therefore, the unexpected impairment of the CWI phenotype encountered in yeast strains either mutated or deleted for PRS1 or PRS5 can be explained by disruption of the communication between primary cell metabolism and CWI signalling. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Necessity of Removing American Football Uniforms From Humans With Hyperthermia Before Cold-Water Immersion.

PubMed

Miller, Kevin C; Long, Blaine C; Edwards, Jeffrey

2015-12-01

The National Athletic Trainers' Association and the American College of Sports Medicine have recommended removing American football uniforms from athletes with exertional heat stroke before cold-water immersion (CWI) based on the assumption that the uniform impedes rectal temperature (T(rec)) cooling. Few experimental data exist to verify or disprove this assumption and the recommendations. To compare CWI durations, T(rec) cooling rates, thermal sensation, intensity of environmental symptoms, and onset of shivering when hyperthermic participants wore football uniforms during CWI or removed the uniforms immediately before CWI. Crossover study. Laboratory. Eighteen hydrated, physically active men (age = 22 ± 2 years, height = 182.5 ± 6.1 cm, mass = 85.4 ± 13.4 kg, body fat = 11% ± 5%, body surface area = 2.1 ± 0.2 m(2)) volunteered. On 2 days, participants exercised in the heat (approximately 40°C, approximately 40% relative humidity) while wearing a full American football uniform (shoes; crew socks; undergarments; shorts; game pants; undershirt; shoulder pads; jersey; helmet; and padding over the thighs, knees, hips, and tailbone [PADS]) until T(rec) reached 39.5°C. Next, participants immersed themselves in water that was approximately 10°C while wearing either undergarments, shorts, and crew socks (NOpads) or PADS without shoes until Trec reached 38°C. The CWI duration (minutes) and T(rec) cooling rates (°C/min). Participants had similar exercise times (NOpads = 40.8 ± 4.9 minutes, PADS = 43.2 ± 4.1 minutes; t(17) = 2.0, P = .10), hypohydration levels (NOpads = 1.5% ± 0.3%, PADS = 1.6% ± 0.4%; t(17) = 1.3, P = .22), and thermal-sensation ratings (NOpads = 7.2 ± 0.3, PADS = 7.1 ± 0.5; P > .05) before CWI. The CWI duration (median [interquartile range]; NOpads = 6.0 [5.4] minutes, PADS = 7.3 [9.8] minutes; z = 2.3, P = .01) and T(rec) cooling rates (NOpads = 0.28°C/min ± 0.14°C/min, PADS = 0.21°C/min ± 0.11°C/min; t(17) = 2.2, P = .02) differed between uniform conditions. Whereas participants cooled faster in NOpads, we still considered the PADS cooling rate to be acceptable (ie, >0.16°C/min). Therefore, if clinicians experience difficulty removing PADS or CWI treatment is delayed, they may immerse fully equipped hyperthermic football players in CWI and maintain acceptable T(rec) cooling rates. Otherwise, PADS should be removed preimmersion to ensure faster body core temperature cooling.
2016 Summer Series - Mark Kasevich: Quantum Mechanics at Macroscopic Scales

NASA Image and Video Library

2016-06-09

The underpinning of the universe is quantum mechanics. It can be used to explain the observed particle and wave nature of atoms. Atom interferometry uses the wave characteristics of atoms to investigate fundamental physics and advance our understanding of the macroscopic world. NASA is working with Dr. Mark Kasevich to apply this technology to advance astrophysics and improve navigation. In his seminar, Kasevich will delve into the world of atom interferometry, gravitational waves and quantum sensors.
Imaging of acoustic fields using optical feedback interferometry.

PubMed

Bertling, Karl; Perchoux, Julien; Taimre, Thomas; Malkin, Robert; Robert, Daniel; Rakić, Aleksandar D; Bosch, Thierry

2014-12-01

This study introduces optical feedback interferometry as a simple and effective technique for the two-dimensional visualisation of acoustic fields. We present imaging results for several pressure distributions including those for progressive waves, standing waves, as well as the diffraction and interference patterns of the acoustic waves. The proposed solution has the distinct advantage of extreme optical simplicity and robustness thus opening the way to a low cost acoustic field imaging system based on mass produced laser diodes.
Effects of Cold Water Immersion and Contrast Water Therapy for Recovery From Team Sport: A Systematic Review and Meta-analysis.

PubMed

Higgins, Trevor R; Greene, David A; Baker, Michael K

2017-05-01

Higgins, TR, Greene, DA, Baker, MK. Effects of cold water immersion and contrast water therapy for recovery from team sport: a systematic review and meta-analysis. J Strength Cond Res 31(5): 1443-1460, 2017-To enhance recovery from sport, cold water immersion (CWI) and contrast water therapy (CWT) have become common practice within high level team sport. Initially, athletes relied solely on anecdotal support. As there has been an increase in the volume of research into recovery including a number of general reviews, an opportunity existed to narrow the focus specifically examining the use of hydrotherapy for recovery in team sport. A Boolean logic [AND] keyword search of databases was conducted: SPORTDiscus; AMED; CINAHL; MEDLINE. Data were extracted and the standardized mean differences were calculated with 95% confidence interval (CI). The analysis of pooled data was conducted using a random-effect model, with heterogeneity assessed using I. Twenty-three peer reviewed articles (n = 606) met the criteria. Meta-analyses results indicated CWI was beneficial for recovery at 24 hours (countermovement jump: p = 0.05, CI: -0.004 to 0.578; All-out sprint: p = 0.02, -0.056 to 0.801) following team sport. The CWI was beneficial for recovery at 72 hours (fatigue: p = 0.03, CI: 0.061-1.418) and CWT was beneficial for recovery at 48 hours (fatigue: p = 0.04, CI: 0.013-0.942) following team sport. The CWI was beneficial for neuromuscular recovery 24 hours following team sport, whereas CWT was not beneficial for recovery following team sport. In addition, when evaluating accumulated sprinting, CWI was not beneficial for recovery following team sports. In evaluating subjective measures, both CWI (72 hours) and CWT (24 hours) were beneficial for recovery of perceptions of fatigue, following team sport. However neither CWI nor CWT was beneficial for recovery, of perceptions of muscle soreness, following team sport.
Modulation of Polarization for Phase Extraction in Holographic Interferometry with Two References

NASA Astrophysics Data System (ADS)

Rodriguez-Zurita, G.; Vázquez-Castillo, J.-F.; Toto-Arellano, N.-I.; Meneses-Fabian, C.; Jiménez-Montero, L.-E.

2010-04-01

Heterodyne holographic interferometry allows high accuracy for phase-difference extraction between two wave fronts, especially when they are previously recorded in the same recording medium. In part, this is because the wave fronts can be affected by the recording process in a very similar way. The double reconstruction of a double-exposure hologram with two independent references results in a two-beam holographic interferometer with an arm conveying a wave modulated in frequency when using heterodyne techniques. The heterodyne frequency has been usually introduced with a plane mirror attached to a piezo-electric stack driven with a suitable variable power supply. For holographic interferometry, however, less attention has been devoted to alternative phase retrieval variants as, for example, phase-shifting with modulation of polarization or Fourier methods. In this work, we propose and demonstrate the basic capabilities of modulation of polarization performing as a phase-shifting technique for holographic interferometry with two references in a phase-stepping scheme. Experimental results are provided.
Direct modeling of coda wave interferometry: comparison of numerical and experimental approaches

NASA Astrophysics Data System (ADS)

Azzola, Jérôme; Masson, Frédéric; Schmittbuhl, Jean

2017-04-01

The sensitivity of coda waves to small changes of the propagation medium is the principle of the coda waves interferometry, a technique which has been found to have a large range of applications over the past years. It exploits the evolution of strongly scattered waves in a limited region of space, to estimate slight changes like the wave velocity of the medium but also the location of scatterer positions or the stress field. Because of the sensitivity of the method, it is of a great value for the monitoring of geothermal EGS reservoir in order to detect fine changes. The aim of this work is thus to monitor the impact of different scatterer distributions and of the loading condition evolution using coda wave interferometry in the laboratory and numerically by modelling the scatter wavefield. In the laboratory, we analyze the scattering of an acoustic wave through a perforated loaded plate of DURAL. Indeed, the localized damages introduced behave as a scatter source. Coda wave interferometry is performed computing correlations of waveforms under different loading conditions, for different scatter distributions. Numerically, we used SPECFEM2D (a 2D spectral element code, (Komatitsch and Vilotte (1998)) to perform 2D simulations of acoustic and elastic seismic wave propagation and enables a direct comparison with laboratory and field results. An unstructured mesh is thus used to simulate the propagation of a wavelet in a loaded plate, before and after introduction of localized damages. The linear elastic deformation of the plate is simulated using Code Aster. The coda wave interferometry is performed similarly to experimental measurements. The accuracy of the comparison of the numerically and laboratory obtained results is strongly depending on the capacity to adapt the laboratory and numerical simulation conditions. In laboratory, the capacity to illuminate the medium in a similar way to that used in the numerical simulation deeply conditions among others the comparison. In the simulation, the gesture of the mesh and its dispersion also influences the rightness of the comparison and interpretation. Moreover, the spectral elements distribution of the mesh and its relative refinement could also be considered as an interesting scatter source.
Including arm exercise during a cold water immersion recovery better assists restoration of sprint cycling performance.

PubMed

Crampton, D; Egaña, M; Donne, B; Warmington, S A

2014-08-01

Sprint (high-intensity) exercise performance is reduced when immediately preceded by cold water immersion (CWI). We aimed to investigate whether this performance effect could be attenuated by combining an active recovery (arm exercise) with hip-level CWI, and whether this attenuation may be related to an effect on core temperature (Tcore ). Participants (n = 8) completed three Wingate tests before (Ex1) and after (Ex2) four different 30-min recovery interventions: CWI at 15 °C (CW15), arm exercise during CWI at 15 °C (CW15+AE), arm exercise during thermoneutral immersion at 34 °C (TW34+AE) and non-immersed arm exercise (AE). After AE and TW34+AE, performance during Ex2 was not different from Ex1; while after CW15+AE and CW15, performance was reduced by 4.9% and 7.6%, respectively. Arm exercise maintained Tcore during recovery in CW15+AE, while it declined to a larger extent upon commencement of Ex2 (-0.9 °C) when compared with CW15 (-0.6 °C). This suggests similar leg muscle cooling during recovery in CW15 and CW15+AE. Without any other significant effects (e.g., on blood lactate), these data suggest that the improvement in sprint performance following an active CWI recovery, over CWI alone, may be related to maintained Tcore and its effect on neurophysiological mechanisms that drive muscle activation, but not by reduced muscle cooling. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Effect of recovery interventions on cycling performance and pacing strategy in the heat.

PubMed

De Pauw, Kevin; Roelands, Bart; Vanparijs, Jef; Meeusen, Romain

2014-03-01

To determine the effect of active recovery (AR), passive rest (PR), and cold-water immersion (CWI) after 90 min of intensive cycling on a subsequent 12-min time trial (TT2) and the applied pacing strategy in TT2. After a maximal test and familiarization trial, 9 trained male subjects (age 22 ± 3 y, VO2max 62.1 ± 5.3 mL · min-1 · kg-1) performed 3 experimental trials in the heat (30°C). Each trial consisted of 2 exercise tasks separated by 1 h. The first was a 60-min constant-load trial at 55% of the maximal power output followed by a 30-min time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, AR, PR, or CWI was applied for 15 min. No significant TT2 performance differences were observed, but a 1-sample t test (within each condition) revealed different pacing strategies during TT2. CWI resulted in an even pacing strategy, while AR and PR resulted in a gradual decline of power output after the onset of TT2 (P ≤ .046). During recovery, AR and CWI showed a trend toward faster blood lactate ([BLa]) removal, but during TT2 significantly higher [BLa] was only observed after CWI compared with PR (P = .011). The pacing strategy during subsequent cycling performance in the heat is influenced by the application of different postexercise recovery interventions. Although power was not significantly altered between groups, CWI enabled a differently shaped power profile, likely due to decreased thermal strain.
Influence of body composition on physiological responses to post-exercise hydrotherapy.

PubMed

Stephens, Jessica M; Halson, Shona L; Miller, Joanna; Slater, Gary J; Askew, Christopher D

2018-05-01

This study examined the influence of body composition on temperature and blood flow responses to post-exercise cold water immersion (CWI), hot water immersion (HWI) and control (CON). Twenty-seven male participants were stratified into three groups: 1) low mass and low fat (LM-LF); 2) high mass and low fat (HM-LF); or 3) high mass and high fat (HM-HF). Experimental trials involved a standardised bout of cycling, maintained until core temperature reached 38.5°C. Participants subsequently completed one of three 15-min recovery interventions (CWI, HWI, or CON). Core, skin and muscle temperatures, and limb blood flow were recorded at baseline, post-exercise, and every 30 min following recovery for 240 min. During CON and HWI there were no differences in core or muscle temperature between body composition groups. The rate of fall in core temperature following CWI was greater in the LM-LF (0.03 ± 0.01°C/min) group compared to the HM-HF (0.01 ± 0.001°C/min) group (P = 0.002). Muscle temperature decreased to a greater extent during CWI in the LM-LF and HM-LF groups (8.6 ± 3.0°C) compared with HM-HF (5.1 ± 2.0°C, P < 0.05). Blood flow responses did not differ between groups. Differences in body composition alter the thermal response to post-exercise CWI, which may explain some of the variance in the responses to CWI recovery.
Measurement of energy contrast of amplified ultrashort pulses using cross-polarized wave generation and spectral interferometry.

PubMed

Iliev, Marin; Meier, Amanda K; Galloway, Benjamin; Adams, Daniel E; Squier, Jeff A; Durfee, Charles G

2014-07-28

We present a method using spectral interferometry (SI) to characterize a pulse in the presence of an incoherent background such as amplified spontaneous emission (ASE). The output of a regenerative amplifier is interfered with a copy of the pulse that has been converted using third-order cross-polarized wave generation (XPW). The ASE shows as a pedestal background in the interference pattern. The energy contrast between the short-pulse component and the ASE is retrieved. The spectra of the interacting beams are obtained through an improvement to the self-referenced spectral interferometry (SRSI) analysis.

Use of Cold-Water Immersion to Reduce Muscle Damage and Delayed-Onset Muscle Soreness and Preserve Muscle Power in Jiu-Jitsu Athletes

PubMed Central

Fonseca, Líllian Beatriz; Brito, Ciro J.; Silva, Roberto Jerônimo S.; Silva-Grigoletto, Marzo Edir; da Silva, Walderi Monteiro; Franchini, Emerson

2016-01-01

Context: Cold-water immersion (CWI) has been applied widely as a recovery method, but little evidence is available to support its effectiveness. Objective: To investigate the effects of CWI on muscle damage, perceived muscle soreness, and muscle power recovery of the upper and lower limbs after jiu-jitsu training. Design: Crossover study. Setting: Laboratory and field. Patients or Other Participants: A total of 8 highly trained male athletes (age = 24.0 ± 3.6 years, mass = 78.4 ± 2.4 kg, percentage of body fat = 13.1% ± 3.6%) completed all study phases. Intervention(s): We randomly selected half of the sample for recovery using CWI (6.0°C ± 0.5°C) for 19 minutes; the other participants were allocated to the control condition (passive recovery). Treatments were reversed in the second session (after 1 week). Main Outcome Measure(s): We measured serum levels of creatine phosphokinase, lactate dehydrogenase (LDH), aspartate aminotransferase, and alanine aminotransferase enzymes; perceived muscle soreness; and recovery through visual analogue scales and muscle power of the upper and lower limbs at pretraining, postrecovery, 24 hours, and 48 hours. Results: Athletes who underwent CWI showed better posttraining recovery measures because circulating LDH levels were lower at 24 hours postrecovery in the CWI condition (441.9 ± 81.4 IU/L) than in the control condition (493.6 ± 97.4 IU/L; P = .03). Estimated muscle power was higher in the CWI than in the control condition for both upper limbs (757.9 ± 125.1 W versus 695.9 ± 56.1 W) and lower limbs (53.7 ± 3.7 cm versus 35.5 ± 8.2 cm; both P values = .001). In addition, we observed less perceived muscle soreness (1.5 ± 1.1 arbitrary units [au] versus 3.1 ± 1.0 au; P = .004) and higher perceived recovery (8.8 ± 1.9 au versus 6.9 ± 1.7 au; P = .005) in the CWI than in the control condition at 24 hours postrecovery. Conclusions: Use of CWI can be beneficial to jiu-jitsu athletes because it reduces circulating LDH levels, results in less perceived muscle soreness, and helps muscle power recovery at 24 hours postrecovery. PMID:27575565
Use of Cold-Water Immersion to Reduce Muscle Damage and Delayed-Onset Muscle Soreness and Preserve Muscle Power in Jiu-Jitsu Athletes.

PubMed

Fonseca, Líllian Beatriz; Brito, Ciro J; Silva, Roberto Jerônimo S; Silva-Grigoletto, Marzo Edir; da Silva, Walderi Monteiro; Franchini, Emerson

2016-07-01

Cold-water immersion (CWI) has been applied widely as a recovery method, but little evidence is available to support its effectiveness. To investigate the effects of CWI on muscle damage, perceived muscle soreness, and muscle power recovery of the upper and lower limbs after jiu-jitsu training. Crossover study. Laboratory and field. A total of 8 highly trained male athletes (age = 24.0 ± 3.6 years, mass = 78.4 ± 2.4 kg, percentage of body fat = 13.1% ± 3.6%) completed all study phases. We randomly selected half of the sample for recovery using CWI (6.0°C ± 0.5°C) for 19 minutes; the other participants were allocated to the control condition (passive recovery). Treatments were reversed in the second session (after 1 week). We measured serum levels of creatine phosphokinase, lactate dehydrogenase (LDH), aspartate aminotransferase, and alanine aminotransferase enzymes; perceived muscle soreness; and recovery through visual analogue scales and muscle power of the upper and lower limbs at pretraining, postrecovery, 24 hours, and 48 hours. Athletes who underwent CWI showed better posttraining recovery measures because circulating LDH levels were lower at 24 hours postrecovery in the CWI condition (441.9 ± 81.4 IU/L) than in the control condition (493.6 ± 97.4 IU/L; P = .03). Estimated muscle power was higher in the CWI than in the control condition for both upper limbs (757.9 ± 125.1 W versus 695.9 ± 56.1 W) and lower limbs (53.7 ± 3.7 cm versus 35.5 ± 8.2 cm; both P values = .001). In addition, we observed less perceived muscle soreness (1.5 ± 1.1 arbitrary units [au] versus 3.1 ± 1.0 au; P = .004) and higher perceived recovery (8.8 ± 1.9 au versus 6.9 ± 1.7 au; P = .005) in the CWI than in the control condition at 24 hours postrecovery. Use of CWI can be beneficial to jiu-jitsu athletes because it reduces circulating LDH levels, results in less perceived muscle soreness, and helps muscle power recovery at 24 hours postrecovery.
Infrasonic interferometry of stratospherically refracted microbaroms--a numerical study.

PubMed

Fricke, Julius T; El Allouche, Nihed; Simons, Dick G; Ruigrok, Elmer N; Wapenaar, Kees; Evers, Läslo G

2013-10-01

The atmospheric wind and temperature can be estimated through the traveltimes of infrasound between pairs of receivers. The traveltimes can be obtained by infrasonic interferometry. In this study, the theory of infrasonic interferometry is verified and applied to modeled stratospherically refracted waves. Synthetic barograms are generated using a raytracing model and taking into account atmospheric attenuation, geometrical spreading, and phase shifts due to caustics. Two types of source wavelets are implemented for the experiments: blast waves and microbaroms. In both numerical experiments, the traveltimes between the receivers are accurately retrieved by applying interferometry to the synthetic barograms. It is shown that microbaroms can be used in practice to obtain the traveltimes of infrasound through the stratosphere, which forms the basis for retrieving the wind and temperature profiles.
Development and applications of optical interferometric micrometrology in the Angstrom and subangstrom range

NASA Technical Reports Server (NTRS)

Lauer, James L.; Abel, Phillip B.

1988-01-01

The characteristics of the scanning tunneling microscope and atomic force microscope (AFM) are briefly reviewed, and optical methods, mainly interferometry, of sufficient resolution to measure AFM deflections are discussed. The methods include optical resonators, laser interferometry, multiple-beam interferometry, and evanescent wave detection. Experimental results using AFM are reviewed.
What is the biochemical and physiological rationale for using cold-water immersion in sports recovery? A systematic review.

PubMed

Bleakley, Chris M; Davison, Gareth W

2010-02-01

Cold-water immersion (CWI) is a popular recovery intervention after exercise. The scientific rationale is not clear, and there are no clear guidelines for its use. The aim of this review was to study the physiological and biochemical effect of short periods of CWI. A computer-based literature search, citation tracking and related articles searches were undertaken. Primary research studies using healthy human participants, immersed in cold water (<15 degrees C), for 5 min durations or less were included. Data were extracted on body temperature, cardiovascular, respiratory and biochemical response. 16 studies were included. Sample size was restricted, and there was a large degree of study heterogeneity. CWI was associated with an increase in heart rate, blood pressure, respiratory minute volume and metabolism. Decreases in end tidal carbon dioxide partial pressure and a decrease in cerebral blood flow were also reported. There was evidence of increases in peripheral catecholamine concentration, oxidative stress and a possible increase in free-radical-species formation. The magnitude of these responses may be attenuated with acclimatisation. CWI induces significant physiological and biochemical changes to the body. Much of this evidence is derived from full body immersions using resting healthy participants. The physiological and biochemical rationale for using short periods of CWI in sports recovery still remains unclear.
The relative efficacy of three recovery modalities after professional rugby league matches.

PubMed

Webb, Nicholas P; Harris, Nigel K; Cronin, John B; Walker, Craig

2013-09-01

This study investigated the relative efficacy of postgame recovery modalities on jump height performance and subjective ratings of muscle soreness and muscle damage at 1, 18, and 42 hours after professional rugby league competition games. Twenty-one professional rugby league players performed 3 different postmatch recovery modalities: cold water immersion (CWI), contrast water therapy (CWT), and active recovery (ACT). The effects of the recovery treatments were analyzed with mixed modeling including a covariate (fatigue score) to adjust for changes in the intensity of each match on the postmatch values of the dependent variables of interest. Standardization of effects was used to make magnitude-based inferences, presented as mean with ±90% confidence limits. Cold water immersion and CWT clearly recovered jump height performance (CWI 2.3 ± 3.7%; CWT 3.5 ± 4.1%), reduced muscle soreness (CWI -0.95 ± 0.37; CWT -0.55 ± 0.37), and decreased creatine kinase (CWI -11.0 ± 15.1%; CWT 18.2 ± 20.1%) by 42 hours postgame compared with ACT. Contrast water therapy was however clearly more effective compared with CWI on the recovery of muscle soreness and creatine kinase by 42 hours postgame. Based on these findings, CWT recovery is recommended postmatch for team rugby sports.
Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training

PubMed Central

Roberts, Llion A; Raastad, Truls; Markworth, James F; Figueiredo, Vandre C; Egner, Ingrid M; Shield, Anthony; Cameron-Smith, David; Coombes, Jeff S; Peake, Jonathan M

2015-01-01

Abstract We investigated functional, morphological and molecular adaptations to strength training exercise and cold water immersion (CWI) through two separate studies. In one study, 21 physically active men strength trained for 12 weeks (2 days per week), with either 10 min of CWI or active recovery (ACT) after each training session. Strength and muscle mass increased more in the ACT group than in the CWI group (P < 0.05). Isokinetic work (19%), type II muscle fibre cross-sectional area (17%) and the number of myonuclei per fibre (26%) increased in the ACT group (all P < 0.05), but not the CWI group. In another study, nine active men performed a bout of single-leg strength exercises on separate days, followed by CWI or ACT. Muscle biopsies were collected before and 2, 24 and 48 h after exercise. The number of satellite cells expressing neural cell adhesion molecule (NCAM) (10−30%) and paired box protein (Pax7) (20−50%) increased 24–48 h after exercise with ACT. The number of NCAM+ satellite cells increased 48 h after exercise with CWI. NCAM+- and Pax7+-positive satellite cell numbers were greater after ACT than after CWI (P < 0.05). Phosphorylation of p70S6 kinaseThr421/Ser424 increased after exercise in both conditions but was greater after ACT (P < 0.05). These data suggest that CWI attenuates the acute changes in satellite cell numbers and activity of kinases that regulate muscle hypertrophy, which may translate to smaller long-term training gains in muscle strength and hypertrophy. The use of CWI as a regular post-exercise recovery strategy should be reconsidered. Key points Cold water immersion is a popular strategy to recover from exercise. However, whether regular cold water immersion influences muscle adaptations to strength training is not well understood. We compared the effects of cold water immersion and active recovery on changes in muscle mass and strength after 12 weeks of strength training. We also examined the effects of these two treatments on hypertrophy signalling pathways and satellite cell activity in skeletal muscle after acute strength exercise. Cold water immersion attenuated long term gains in muscle mass and strength. It also blunted the activation of key proteins and satellite cells in skeletal muscle up to 2 days after strength exercise. Individuals who use strength training to improve athletic performance, recover from injury or maintain their health should therefore reconsider whether to use cold water immersion as an adjuvant to their training. PMID:26174323
Necessity of Removing American Football Uniforms From Humans With Hyperthermia Before Cold-Water Immersion

PubMed Central

Miller, Kevin C.; Long, Blaine C.; Edwards, Jeffrey

2015-01-01

Context The National Athletic Trainers' Association and the American College of Sports Medicine have recommended removing American football uniforms from athletes with exertional heat stroke before cold-water immersion (CWI) based on the assumption that the uniform impedes rectal temperature (Trec) cooling. Few experimental data exist to verify or disprove this assumption and the recommendations. Objectives To compare CWI durations, Trec cooling rates, thermal sensation, intensity of environmental symptoms, and onset of shivering when hyperthermic participants wore football uniforms during CWI or removed the uniforms immediately before CWI. Design Crossover study. Setting Laboratory. Patients or Other Participants Eighteen hydrated, physically active men (age = 22 ± 2 years, height = 182.5 ± 6.1 cm, mass = 85.4 ± 13.4 kg, body fat = 11% ± 5%, body surface area = 2.1 ± 0.2 m2) volunteered. Intervention(s) On 2 days, participants exercised in the heat (approximately 40°C, approximately 40% relative humidity) while wearing a full American football uniform (shoes; crew socks; undergarments; shorts; game pants; undershirt; shoulder pads; jersey; helmet; and padding over the thighs, knees, hips, and tailbone [PADS]) until Trec reached 39.5°C. Next, participants immersed themselves in water that was approximately 10°C while wearing either undergarments, shorts, and crew socks (NOpads) or PADS without shoes until Trec reached 38°C. Main Outcome Measure(s) The CWI duration (minutes) and Trec cooling rates (°C/min). Results Participants had similar exercise times (NOpads = 40.8 ± 4.9 minutes, PADS = 43.2 ± 4.1 minutes; t17 = 2.0, P = .10), hypohydration levels (NOpads = 1.5% ± 0.3%, PADS = 1.6% ± 0.4%; t17 = 1.3, P = .22), and thermal-sensation ratings (NOpads = 7.2 ± 0.3, PADS = 7.1 ± 0.5; P > .05) before CWI. The CWI duration (median [interquartile range]; NOpads = 6.0 [5.4] minutes, PADS = 7.3 [9.8] minutes; z = 2.3, P = .01) and Trec cooling rates (NOpads = 0.28°C/min ± 0.14°C/min, PADS = 0.21°C/min ± 0.11°C/min; t17 = 2.2, P = .02) differed between uniform conditions. Conclusions Whereas participants cooled faster in NOpads, we still considered the PADS cooling rate to be acceptable (ie, >0.16°C/min). Therefore, if clinicians experience difficulty removing PADS or CWI treatment is delayed, they may immerse fully equipped hyperthermic football players in CWI and maintain acceptable Trec cooling rates. Otherwise, PADS should be removed preimmersion to ensure faster body core temperature cooling. PMID:26678288
Monitoring the englacial fracture state using virtual-reflector seismology

NASA Astrophysics Data System (ADS)

Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

2017-12-01

Fracturing and changes in the englacial macroscopic water content change the elastic bulk properties of ice bodies. Small seismic velocity variations, resulting from such changes, can be measured using a technique called coda-wave interferometry. Here, coda refers to the later-arriving, multiply scattered waves. Often, this technique is applied to so-called virtual-source responses, which can be obtained using seismic interferometry (a simple crosscorrelation process). Compared to other media (e.g., the Earth's crust), however, ice bodies exhibit relatively little scattering. This complicates the application of coda-wave interferometry to the retrieved virtual-source responses. In this work, we therefore investigate the applicability of coda-wave interferometry to virtual-source responses obtained using two alternative seismic interferometric techniques, namely, seismic interferometry by multidimensional deconvolution (SI by MDD), and virtual-reflector seismology (VRS). To that end, we use synthetic data, as well as active-source glacier data acquired on Glacier de la Plaine Morte, Switzerland. Both SI by MDD and VRS allow the retrieval of more accurate virtual-source responses. In particular, the dependence of the retrieved virtual-source responses on the illumination pattern is reduced. We find that this results in more accurate glacial phase-velocity estimates. In addition, VRS introduces virtual reflections from a receiver contour (partly) enclosing the medium of interest. By acting as a sort of virtual reverberation, the coda resulting from the application of VRS significantly increases seismic monitoring capabilities, in particular in cases where natural scattering coda is not available.
Cold water immersion recovery following intermittent-sprint exercise in the heat.

PubMed

Pointon, Monique; Duffield, Rob; Cannon, Jack; Marino, Frank E

2012-07-01

This study examined the effects of cold water immersion (CWI) on recovery of neuromuscular function following simulated team-sport exercise in the heat. Ten male team-sport athletes performed two sessions of a 2 × 30-min intermittent-sprint exercise (ISE) in 32°C and 52% humidity, followed by a 20-min CWI intervention or passive recovery (CONT) in a randomized, crossover design. The ISE involved a 15-m sprint every minute separated by bouts of hard running, jogging and walking. Voluntary and evoked neuromuscular function, ratings of perceived muscle soreness (MS) and blood markers for muscle damage were measured pre- and post-exercise, immediately post-recovery, 2-h and 24-h post-recovery. Measures of core temperature (Tcore), heart rate (HR), capillary blood and perceptions of exertion, thermal strain and thirst were also recorded at the aforementioned time points. Post-exercise maximal voluntary contraction (MVC) and activation (VA) were reduced in both conditions and remained below pre-exercise values for the 24-h recovery (P < 0.05). Increased blood markers of muscle damage were observed post-exercise in both conditions and remained elevated for the 24-h recovery period (P < 0.05). Comparative to CONT, the post-recovery rate of reduction in Tcore, HR and MS was enhanced with CWI whilst increasing MVC and VA (P < 0.05). In contrast, 24-h post-recovery MVC and activation were significantly higher in CONT compared to CWI (P = 0.05). Following exercise in the heat, CWI accelerated the reduction in thermal and cardiovascular load, and improved MVC alongside increased central activation immediately and 2-h post-recovery. However, despite improved acute recovery CWI resulted in an attenuated MVC 24-h post-recovery.
Reassessment of an Arabidopsis cell wall invertase inhibitor AtCIF1 reveals its role in seed germination and early seedling growth.

PubMed

Su, Tao; Wolf, Sebastian; Han, Mei; Zhao, Hongbo; Wei, Hongbin; Greiner, Steffen; Rausch, Thomas

2016-01-01

In higher plants, cell wall invertase (CWI) and vacuolar invertase (VI) are recognized as essential players in sugar metabolism and sugar signaling, thereby affecting source-sink interactions, plant development and responses to environmental cues. CWI and VI expression levels are transcriptionally controlled; however, both enzymes are also subject to posttranslational control by invertase inhibitor proteins. The physiological significances of inhibitor proteins during seed germination and early seedling development are not yet fully understood. Here, we demonstrate that the inhibitor isoform AtCIF1 impacted on seed germination and early seedling growth in Arabidopsis. The primary target of AtCIF1 was shown to be localized to the apoplast after expressing an AtCIF1 YFP-fusion construct in tobacco epidermis and transgenic Arabidopsis root. The analysis of expression patterns showed that AtCWI1 was co-expressed spatiotemporally with AtCIF1 within the early germinating seeds. Seed germination was observed to be accelerated independently of exogenous abscisic acid (ABA) in the AtCIF1 loss-of-function mutant cif1-1. This effect coincided with a drastic increase of CWI activity in cif1-1 mutant seeds by 24 h after the onset of germination, both in vitro and in planta. Accordingly, quantification of sugar content showed that hexose levels were significantly boosted in germinating seeds of the cif1-1 mutant. Further investigation of AtCIF1 overexpressors in Arabidopsis revealed a markedly suppressed CWI activity as well as delayed seed germination. Thus, we conclude that the posttranslational modulation of CWI activity by AtCIF1 helps to orchestrate seed germination and early seedling growth via fine-tuning sucrose hydrolysis and, possibly, sugar signaling.
Cold-water immersion decreases cerebral oxygenation but improves recovery after intermittent-sprint exercise in the heat.

PubMed

Minett, G M; Duffield, R; Billaut, F; Cannon, J; Portus, M R; Marino, F E

2014-08-01

This study examined the effects of post-exercise cooling on recovery of neuromuscular, physiological, and cerebral hemodynamic responses after intermittent-sprint exercise in the heat. Nine participants underwent three post-exercise recovery trials, including a control (CONT), mixed-method cooling (MIX), and cold-water immersion (10 °C; CWI). Voluntary force and activation were assessed simultaneously with cerebral oxygenation (near-infrared spectroscopy) pre- and post-exercise, post-intervention, and 1-h and 24-h post-exercise. Measures of heart rate, core temperature, skin temperature, muscle damage, and inflammation were also collected. Both cooling interventions reduced heart rate, core, and skin temperature post-intervention (P < 0.05). CWI hastened the recovery of voluntary force by 12.7 ± 11.7% (mean ± SD) and 16.3 ± 10.5% 1-h post-exercise compared to MIX and CONT, respectively (P < 0.01). Voluntary force remained elevated by 16.1 ± 20.5% 24-h post-exercise after CWI compared to CONT (P < 0.05). Central activation was increased post-intervention and 1-h post-exercise with CWI compared to CONT (P < 0.05), without differences between conditions 24-h post-exercise (P > 0.05). CWI reduced cerebral oxygenation compared to MIX and CONT post-intervention (P < 0.01). Furthermore, cooling interventions reduced cortisol 1-h post-exercise (P < 0.01), although only CWI blunted creatine kinase 24-h post-exercise compared to CONT (P < 0.05). Accordingly, improvements in neuromuscular recovery after post-exercise cooling appear to be disassociated with cerebral oxygenation, rather reflecting reductions in thermoregulatory demands to sustain force production. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability.

PubMed

Stanley, Jamie; Buchheit, Martin; Peake, Jonathan M

2012-03-01

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R-R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R-R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; -12% (-18; -5)]) and CWT [-11% (-19; -2)]. Leg soreness was almost certainly lower following CWI [-22% (-30; -14)] and CWT [-27% (-37; -15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD(Post-interv)) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (-0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD(Post-interv) and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD(Post-interv) and leg soreness [r = -0.50 (-0.66; -0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies.
Effect of Body Composition on Physiological Responses to Cold-Water Immersion and the Recovery of Exercise Performance.

PubMed

Stephens, Jessica M; Halson, Shona L; Miller, Joanna; Slater, Gary J; Chapman, Dale W; Askew, Christopher D

2018-03-01

To explore the influence of body composition on thermal responses to cold-water immersion (CWI) and the recovery of exercise performance. Male subjects were stratified into 2 groups: low fat (LF; n = 10) or high fat (HF; n = 10). Subjects completed a high-intensity interval test (HIIT) on a cycle ergometer followed by a 15-min recovery intervention (control [CON] or CWI). Core temperature (T c ), skin temperature, and heart rate were recorded continuously. Performance was assessed at baseline, immediately post-HIIT, and 40 min postrecovery using a 4-min cycling time trial (TT), countermovement jump (CMJ), and isometric midthigh pull (IMTP). Perceptual measures (thermal sensation [TS], total quality of recovery [TQR], soreness, and fatigue) were also assessed. T c and TS were significantly lower in LF than in HF from 10 min (T c, LF 36.5°C ± 0.5°C, HF 37.2°C ± 0.6°C; TS, LF 2.3 ± 0.5 arbitrary units [a.u.], HF 3.0 ± 0.7 a.u.) to 40 min (T c , LF 36.1°C ± 0.6°C, HF 36.8°C ±0.7°C; TS, LF 2.3 ± 0.6 a.u., HF 3.2 ± 0.7 a.u.) after CWI (P < .05). Recovery of TT performance was significantly enhanced after CWI in HF (10.3 ± 6.1%) compared with LF (3.1 ± 5.6%, P = .01); however, no differences were observed between HF (6.9% ±5.7%) and LF (5.4% ± 5.2%) with CON. No significant differences were observed between groups for CMJ, IMTP, TQR, soreness, or fatigue in either condition. Body composition influences the magnitude of T c change during and after CWI. In addition, CWI enhanced performance recovery in the HF group only. Therefore, body composition should be considered when planning CWI protocols to avoid overcooling and maximize performance recovery.
The use of thermal imaging to assess the effectiveness of ice massage and cold-water immersion as methods for supporting post-exercise recovery.

PubMed

Adamczyk, Jakub Grzegorz; Krasowska, Ilona; Boguszewski, Dariusz; Reaburn, Peter

2016-08-01

Cold water immersion (CWI) and ice massage (IM) are commonly used treatments to prevent the delay onset of muscle soreness (DOMS); however, little is known on their relative benefits and effectiveness to lower tissue temperature. This study was designed to evaluate the effectiveness of IM and CMI on tissue temperature and potential benefit to preventing DOMS. The research encompassed 36 subjects divided into three groups of twelve depending on the form of recovery: ice massage (IM), cold-water immersion (CWI), or passive recovery (PAS). All the participants were asked to jump as high as possible from a full squat for one minute. Thermal imaging was conducted at rest, immediately following the exercise, immediately after the trial, following the recovery treatment, and after 30min of rest. Their pain levels were assessed using the Visual Analogue Scale (VAS). After applying the selected method for supporting recovery, the LA level decreased by 4.25mmol/L in the IM group, and by 4.96mmol/L in the CWI group (IM vs. CWI p>0.05). The 2.75mmol/L decrease in lactate concentration in the PAS group was significantly lower than in the other groups (IM vs. PAS p<0.05/ CWI vs. PAS p<0.01). In both groups, Tsk after 30min was significantly lower (ΔTsk~0.5°C) than at rest (p<0.05). In turn, Tsk in the PAS group returned to the resting values (p>0.05). Seventy-two hours after the exercise, a clear decrease in discomfort was observed in the IM and CWI groups compared to the PAS group. The two applied treatments have proven to be effective both in utilizing lactate and preventing DOMS. Depending on training requirements, we recommend the use of IM when athletes experience localized muscle fatigue. One the other hand, CWI is recommended in situations of global or generalized muscle injury or fatigue. Copyright © 2016 Elsevier Ltd. All rights reserved.
Denoising in digital speckle pattern interferometry using wave atoms.

PubMed

Federico, Alejandro; Kaufmann, Guillermo H

2007-05-15

We present an effective method for speckle noise removal in digital speckle pattern interferometry, which is based on a wave-atom thresholding technique. Wave atoms are a variant of 2D wavelet packets with a parabolic scaling relation and improve the sparse representation of fringe patterns when compared with traditional expansions. The performance of the denoising method is analyzed by using computer-simulated fringes, and the results are compared with those produced by wavelet and curvelet thresholding techniques. An application of the proposed method to reduce speckle noise in experimental data is also presented.
Advanced wave field sensing using computational shear interferometry

NASA Astrophysics Data System (ADS)

Falldorf, Claas; Agour, Mostafa; Bergmann, Ralf B.

2014-07-01

In this publication we give a brief introduction into the field of Computational Shear Interferometry (CoSI), which allows for determining arbitrary wave fields from a set of shear interferograms. We discuss limitations of the method with respect to the coherence of the underlying wave field and present various numerical methods to recover it from its sheared representations. Finally, we show experimental results on Digital Holography of objects with rough surface using a fiber coupled light emitting diode and quantitative phase contrast imaging as well as numerical refocusing in Differential Interference Contrast (DIC) microscopy.
Comparable Wages, Inflation, and School Finance Equity

ERIC Educational Resources Information Center

Taylor, Lori L.

2006-01-01

A Comparable Wage Index (CWI) is an attractive mechanism for measuring geographic variations in the cost of education. A CWI measures uncontrollable variations in educator pay by observing systematic variations in the earnings of comparable workers who are not educators. Together, the 2000 census and the Occupational Employment Statistics survey…
Stability of the IMEX Methods, CNLF and BDF2-AB2, for Uncoupling Systems of Evolution Equations

DTIC Science & Technology

2011-02-01

Implicit-Explicit linear multistep methods, Tech. rep., Centrum Wiskunde and Informatica (CWI) (1996). [14] W. Hundsdorfer, J. Verwer, Numerical...component splitting for the Crank-Nicolson Leap- Frog integration method, Tech. rep., Centrum Wiskunde and Informatica (CWI) (2009). [23] J. Verwer
Can repeating glacial seismic events be used to monitor stress changes within the underlying volcano? -Case study from the glacier overlain Katla volcano, Iceland

NASA Astrophysics Data System (ADS)

Jonsdottir, K.; Vogfjord, K. S.; Bean, C. J.; Martini, F.

2013-12-01

The glacier overlain Katla volcano in South Iceland, is one of the most active and hazardous volcano in Europe. Katla eruptions result in hazardous glacial floods and intense tephra fall. On average there are eruptions every 50 years but the volcano is long overdue and we are now witnessing the longest quiescence period in 1000 years or since the settlement. Because of the hazard the volcano poses, it is under constant surveillance and gets a good share of the seismic stations from the national seismic network. Every year the seismic network records thousands of seismic events at Katla with magnitudes seldom exceeding M3. The bulk of the seismicity is however not due to volcano tectonics but seems to be caused mainly by shallow processes involving glacial deformation. Katla's ice filled caldera forms a glacier plateau of several hundred meters thick ice. The 9x14 km oval caldera is surrounded by higher rims where the glacier in some places gently and in others abruptly falls off tens and up to hundred meters to the surrounding lowland. The glacier surface is marked with dozen depressions or cauldrons which manifest geothermal activity below, probably coinciding with circular faults around the caldera. Our current understanding is that there are several glacial processes which cause seismicity; these include dry calving, where steep valley glaciers fall off cliffs and movements of glacier ice as the cauldrons deform due to hydraulic changes and geothermal activity at the glacier/bedrock boundary. These glacial events share a common feature of containing low frequency (2-4 hz) and long coda. Because of their shallow origin, surface waves are prominent. In our analysis we use waveforms from all of Katla's seismic events between years 2003-2013, with the criteria M>1 and minimum 4 p-wave picks. We correlate the waveforms of these events with each other and group them into families of highly similar events. Looking at the occurrence of these families we find that individual families are usually clustered in time over several months, and sometimes families may reappear even up to several years later. Using families including many events and covering long periods (10-20 months) we compare the coda (the tail) of individual events within a family. This is repeated for all the surrounding stations. The analysis, coda wave interferometry (cwi) is a correlation method that builds on the fact that changes in stress in the edifice lead to changes in seismic velocities. The coda waves are highly sensitive to small stress changes. By using a repeating source, implying we have the same source mechanism and the same path, we can track temporal stress changes in the medium between the source and the receiver. Preliminary results from Katla suggest that by using the repeating glacial events and the coda wave interferometry technique we observe annual seismic velocity changes around the volcano of ca. 0.7%. We find that seismic velocities increase from January through July and decrease in August to December. These changes can be explained by pore-water pressure changes and/or loading and de-loading of the overlain glacier. We do not find immediate precursors for an impending eruption at Katla; however we now have a better understanding of its background seismicity.

Coda-wave and ambient noise interferometry using an offset vertical array at Iwanuma site, northeast Japan

NASA Astrophysics Data System (ADS)

Minami, K.; Yamamoto, M.; Nishimura, T.; Nakahara, H.; Shiomi, K.

2013-12-01

Seismic interferometry using vertical borehole arrays is a powerful tool to estimate the shallow subsurface structure and its time lapse changes. However, the wave fields surrounding borehole arrays are non-isotropic due to the existence of ground surface and non-uniform distribution of sources, and do not meet the requirements of the seismic interferometry in a strict sense. In this study, to examine differences between wave fields of coda waves and ambient noise, and to estimate their effects on the results of seismic interferometry, we conducted a temporal seismic experiment using zero-offset and offset vertical arrays. We installed two 3-components seismometers (hereafter called Surface1 and Surface2) at the ground surface in the vicinity of NIED Iwanuma site (Miyagi Pref., Japan). Surface1 is placed just above the Hi-net downhole seismometer whose depth is 101 m, and Surface2 is placed 70 m away from Surface1. To extract the wave propagation between these 3 seismometers, we compute the cross-correlation functions (CCFs) of coda-wave and ambient noise for each pair of the zero-offset vertical (Hi-net-Surface1), finite-offset vertical (Hi-net-Surface2), and horizontal (Surface1-Surface2) arrays. We use the frequency bands of 4-8, 8-16 Hz in the CCF computation. The characteristics of obtained CCFs are summarized as follows; (1) in all frequency bands, the peak lag times of CCFs from coda waves are almost the same between the vertical and offset-vertical arrays irrespective of different inter-station distance, and those for the horizontal array are around 0 s. (2) the peak lag times of CCFs from ambient noise show slight differences, that is, those obtained from the vertical array are earlier than those from the offset-vertical array, and those from the horizontal array are around 0.05 s. (3) the peak lag times of CCFs for the vertical array obtained from ambient noise analyses are earlier than those from the coda-wave analyses. These results indicate that wave fields of coda-wave are mainly composed of vertically propagating waves, while those of ambient noise are composed of both vertically and horizontally propagating waves. To explain these characteristics of the CCFs obtained from different wave fields, we conducted a numerical simulation of interferometry based on the concept of stationary phase. Here, we assume isotropic upward incidence of SV-wave into a homogeneous half-space, and compute CCFs for the zero-offset and finite-offset vertical arrays by taking into account the reflection and conversion of P-SV waves at the free surface. Due to the effectively non-isotropic wave field, the simulated CCF for the zero-offset vertical array shows slight delay in peak lag time and its amplitudes decrease in the acausal part. On the other hand, the simulated CCF for finite-offset vertical array shows amplitude decrease and no peak lag time shift. These results are consistent with the difference in peak lag times obtained from coda-wave and ambient noise analyses. Our observations and theoretical consideration suggest that the careful consideration of wave fields is important in the application of seismic interferometry to borehole array data.
Child Well-Being Index (CWI), 2010

ERIC Educational Resources Information Center

Foundation for Child Development, 2010

2010-01-01

Each year, the Foundation for Child Development and the Child and Youth Well-Being Index Project at Duke University issue a comprehensive measure of how children are faring in the United States. The Overall Composite Child Well-Being Index (CWI) is based on a composite of 28 "Key Indicators" of well-being that are grouped into seven…
Clinical features and the degree of cerebrovascular stenosis in different types and subtypes of cerebral watershed infarction.

PubMed

Li, Yue; Li, Man; Zhang, Xiaoyu; Yang, Shuna; Fan, Huimin; Qin, Wei; Yang, Lei; Yuan, Junliang; Hu, Wenli

2017-08-29

Whether there are differences in pathogenesis among different types and subtypes of cerebral watershed infarction (WSI) is controversial since they have been combined into a single group in most previous studies. We prospectively identified 340 supratentorial WSI patients at Beijing Chao-Yang Hospital, Capital Medical University, China and classified them based on diffusion-weighted imaging(DWI) templates. Baseline characteristics, clinical courses and neuroradiological features were compared among patients with different types and subtypes of WSI. We identified 92 patients with cortical watershed infarction (CWI), 112 with internal watershed infarction (IWI) and 136 with mixed-type infarction. Compared with CWI patients, more IWI patients had critical stenosis of internal carotid artery (ICA) (P < 0.001). For the CWI group, patients with anterior watershed infarction (AWI) were more prone to critical ICA stenosis than those with posterior watershed infarction (PWI) (P = 0.011). For the IWI group, critical ICA stenosis was more prevalent in patients with partial IWI (P-IWI) than in those with confluent IWI (C-IWI) (P = 0.026). IWI patients were more frequently found to have clinical deterioration during the first 7 days of hospitalization and a poor prognosis at the 90th day than in CWI patients (P = 0.003 and P = 0.014, respectively). IWI, especially the P-IWI subtype, is associated with hemodynamic impairment (HDI), whereas CWI has a weaker correlation with ICA steno-occlusion. Furthermore, IWI patients are more prone to poor prognosis.
Portable fiber optic coupled Doppler interferometer system for detonation and shock wave diagnostics

NASA Technical Reports Server (NTRS)

Fleming, Kevin J.

1993-01-01

Testing and analysis of shock wave characteristics such as detonators and ground shock propagation frequently require a method of measuring velocity and displacement of the surface of interest. One method of measurement is Doppler interferometry. The VISAR (Velocity Interferometer System for Any Reflector) uses Doppler interferometry and has gained wide acceptance as the preferred tool for shock measurement. An important asset of VISAR is that it measures velocity and displacement nonintrusively.
Evaluation of crack status in a meter-size concrete structure using the ultrasonic nonlinear coda wave interferometry.

PubMed

Legland, Jean-Baptiste; Zhang, Yuxiang; Abraham, Odile; Durand, Olivier; Tournat, Vincent

2017-10-01

The field of civil engineering is in need of new methods of non-destructive testing, especially in order to prevent and monitor the serious deterioration of concrete structures. In this work, experimental results are reported on fault detection and characterization in a meter-scale concrete structure using an ultrasonic nonlinear coda wave interferometry (NCWI) method. This method entails the nonlinear mixing of strong pump waves with multiple scattered probe (coda) waves, along with analysis of the net effect using coda wave interferometry. A controlled damage protocol is implemented on a post-tensioned, meter-scale concrete structure in order to generate cracking within a specific area being monitored by NCWI. The nonlinear acoustic response due to the high amplitude of acoustic modulation yields information on the elastic nonlinearities of concrete, as evaluated by two specific nonlinear observables. The increase in nonlinearity level corresponds to the creation of a crack with a network of microcracks localized at its base. In addition, once the crack closes as a result of post-tensioning, the residual nonlinearities confirm the presence of the closed crack. Last, the benefits and applicability of this NCWI method to the characterization and monitoring of large structures are discussed.
Seismic interferometry of railroad induced ground motions: body and surface wave imaging

NASA Astrophysics Data System (ADS)

Quiros, Diego A.; Brown, Larry D.; Kim, Doyeon

2016-04-01

Seismic interferometry applied to 120 hr of railroad traffic recorded by an array of vertical component seismographs along a railway within the Rio Grande rift has recovered surface and body waves characteristic of the geology beneath the railway. Linear and hyperbolic arrivals are retrieved that agree with surface (Rayleigh), direct and reflected P waves observed by nearby conventional seismic surveys. Train-generated Rayleigh waves span a range of frequencies significantly higher than those recovered from typical ambient noise interferometry studies. Direct P-wave arrivals have apparent velocities appropriate for the shallow geology of the survey area. Significant reflected P-wave energy is also present at relatively large offsets. A common midpoint stack produces a reflection image consistent with nearby conventional reflection data. We suggest that for sources at the free surface (e.g. trains) increasing the aperture of the array to record wide angle reflections, in addition to longer recording intervals, might allow the recovery of deeper geological structure from railroad traffic. Frequency-wavenumber analyses of these recordings indicate that the train source is symmetrical (i.e. approaching and receding) and that deeper refracted energy is present although not evident in the time-offset domain. These results confirm that train-generated vibrations represent a practical source of high-resolution subsurface information, with particular relevance to geotechnical and environmental applications.
Theoretical Properties of Acoustical Speckle Interferometry.

DTIC Science & Technology

1980-09-01

an obvious one , since it was first performed in the acoustical holography. An acoustical speckle interferometry study has been demonstrated to be a...experiments in which pulses were used to study the propagation of the circumferential waves on aluminum cylinders immersed in water. In 1969, Bunney...destructive Testing SB. ABTRACT aCdo as revers. NW ass a" Id by block numb") Acoustical speckle interferometry is based locally on the elastodynamic response
Peptides and proteins in matter wave interferometry: Challenges and prospects

NASA Astrophysics Data System (ADS)

Sezer, Ugur; Geyer, Philipp; Mairhofer, Lukas; Brand, Christian; Doerre, Nadine; Rodewald, Jonas; Schaetti, Jonas; Koehler, Valentin; Mayor, Marcel; Arndt, Markus

2016-05-01

Recent developments in matter wave physics suggest that quantum interferometry with biologically relevant nanomaterials is becoming feasible for amino acids, peptides, proteins and RNA/DNA strands. Quantum interference of biomolecules is interesting as it can mimic Schrödinger's cat states with molecules of high mass, elevated temperature and biological functionality. Additionally, the high internal complexity can give rise to a rich variety of couplings to the environment and new handles for quantitative tests of quantum decoherence. Finally, matter wave interferometers are highly sensitive force sensors and pave the way for quantum-assisted measurements of biomolecular properties in interaction with tailored or biomimetic environments. Recent interferometer concepts such as the Kapitza-Dirac-Talbot-Lau interferometer (KDTLI) or the Optical Time-domain Matter Wave interferometer (OTIMA) have already proven their potential for quantum optics in the mass range beyond 10000 amu and for metrology. Here we show our advances in quantum interferometry with vitamins and peptides and discuss methods of realizing cold, intense and sufficiently slow beams of synthetically tailored or hydrated polypeptides with promising properties for a new generation of quantum optics.
Child and Youth Well-Being Index (CWI), 2011

ERIC Educational Resources Information Center

Foundation for Child Development, 2011

2011-01-01

Each year, the Foundation for Child Development and the Child and Youth Well-Being Index Project at Duke University issue a comprehensive measure of how children are faring in the United States. The overall comprehensive Child Well-Being Index (CWI) is based on a composite of 28 Key Indicators of well-being that are grouped into seven…
The critical angle in seismic interferometry

USGS Publications Warehouse

Van Wijk, K.; Calvert, A.; Haney, M.; Mikesell, D.; Snieder, R.

2008-01-01

Limitations with respect to the characteristics and distribution of sources are inherent to any field seismic experiment, but in seismic interferometry these lead to spurious waves. Instead of trying to eliminate, filter or otherwise suppress spurious waves, crosscorrelation of receivers in a refraction experiment indicate we can take advantage of spurious events for near-surface parameter extraction for static corrections or near-surface imaging. We illustrate this with numerical examples and a field experiment from the CSM/Boise State University Geophysics Field Camp.
Application of optical interferometry in focused acoustic field measurement

NASA Astrophysics Data System (ADS)

Wang, Yuebing; Sun, Min; Cao, Yonggang; Zhu, Jiang

2018-07-01

Optical interferometry has been successfully applied in measuring acoustic pressures in plane-wave fields and spherical-wave fields. In this paper, the "effective" refractive index for focused acoustic fields was developed, through numerical simulation and experiments, the feasibility of the optical method in measuring acoustic fields of focused transducers was proved. Compared with the results from a membrane hydrophone, it was concluded that the optical method has good spatial resolution and is suitable for detecting focused fields with fluctuant distributions. The influences of a few factors (the generated lamb wave, laser beam directivity, etc.) were analyzed, and corresponding suggestions were proposed for effective application of this technology.
Double-path acquisition of pulse wave transit time and heartbeat using self-mixing interferometry

NASA Astrophysics Data System (ADS)

Wei, Yingbin; Huang, Wencai; Wei, Zheng; Zhang, Jie; An, Tong; Wang, Xiulin; Xu, Huizhen

2017-06-01

We present a technique based on self-mixing interferometry for acquiring the pulse wave transit time (PWTT) and heartbeat. A signal processing method based on Continuous Wavelet Transform and Hilbert Transform is applied to extract potentially useful information in the self-mixing interference (SMI) signal, including PWTT and heartbeat. Then, some cardiovascular characteristics of the human body are easily acquired without retrieving the SMI signal by complicated algorithms. Experimentally, the PWTT is measured on the finger and the toe of the human body using double-path self-mixing interferometry. Experimental statistical data show the relation between the PWTT and blood pressure, which can be used to estimate the systolic pressure value by fitting. Moreover, the measured heartbeat shows good agreement with that obtained by a photoplethysmography sensor. The method that we demonstrate, which is based on self-mixing interferometry with significant advantages of simplicity, compactness and non-invasion, effectively illustrates the viability of the SMI technique for measuring other cardiovascular signals.
Recovery following a marathon: a comparison of cold water immersion, whole body cryotherapy and a placebo control.

PubMed

Wilson, Laura J; Cockburn, Emma; Paice, Katherine; Sinclair, Scott; Faki, Tanwir; Hills, Frank A; Gondek, Marcela B; Wood, Alyssa; Dimitriou, Lygeri

2018-01-01

Cryotherapy is an increasingly popular recovery strategy used in an attempt to attenuate the negative impact of strenuous physical activity on subsequent exercise. Therefore, this study aimed to assess the effects of whole body cryotherapy (WBC) and cold water immersion (CWI) on markers of recovery following a marathon. Thirty-one endurance trained males completed a marathon. Participants were randomly assigned to a CWI, WBC or placebo group. Perceptions of muscle soreness, training stress and markers of muscle function were recorded before the marathon and at 24 and 48 h post exercise. Blood samples were taken at baseline, post intervention and 24 and 48 h post intervention to assess inflammation and muscle damage. WBC had a harmful effect on muscle function compared to CWI post marathon. WBC positively influenced perceptions of training stress compared to CWI. With the exception of C-reactive protein (CRP) at 24 and 48 h, neither cryotherapy intervention positively influenced blood borne markers of inflammation or structural damage compared to placebo. The findings show WBC has a negative impact on muscle function, perceptions of soreness and a number of blood parameters compared to CWI, contradicting the suggestion that WBC may be a superior recovery strategy. Further, cryotherapy is no more effective than a placebo intervention at improving functional recovery or perceptions of training stress following a marathon. These findings lend further evidence to suggest that treatment belief and the placebo effect may be largely responsible for the beneficial effects of cryotherapy on recovery following a marathon.
The 2009 Foundation for Child Development Child and Youth Well-Being Index (CWI) Report

ERIC Educational Resources Information Center

Foundation for Child Development, 2009

2009-01-01

The Foundation for Child Development Child and Youth Well-Being Index Project at Duke University issues an annual comprehensive measure of how children are faring in the United States. The Child Well-Being Index (CWI) is based on a composite of 28 "Key Indicators" of wellbeing that are grouped into seven "Quality-of-Life/Well-Being…
National Child and Youth Well-Being Index (CWI), 2012

ERIC Educational Resources Information Center

Foundation for Child Development, 2012

2012-01-01

Each year, the Foundation for Child Development (FCD) and the Child and Youth Well-Being Index Project at Duke University issue a comprehensive measure of how children are faring in the United States. The resultant NATIONAL Child and Youth Well-Being Index (CWI) is based on a composite of "28 Key Indicators of well-being that are grouped into…
Documentation for the NCES Comparable Wage Index Files. EFSC 2006-865

ERIC Educational Resources Information Center

Taylor, Lori L.; Glander, Mark C.

2006-01-01

The Comparable Wage Index (CWI) is a measure of the systematic, regional variations in the salaries of college graduates who are not educators. It can be used by researchers to adjust district-level finance data at different levels in order to make better comparisons across geographic areas. The CWI was developed by Dr. Lori L. Taylor at the Bush…
The CWI Pathway: Regulation of the Transcriptional Adaptive Response to Cell Wall Stress in Yeast

PubMed Central

Sanz, Ana Belén; García, Raúl; Rodríguez-Peña, José M.; Arroyo, Javier

2017-01-01

Fungi are surrounded by an essential structure, the cell wall, which not only confers cell shape but also protects cells from environmental stress. As a consequence, yeast cells growing under cell wall damage conditions elicit rescue mechanisms to provide maintenance of cellular integrity and fungal survival. Through transcriptional reprogramming, yeast modulate the expression of genes important for cell wall biogenesis and remodeling, metabolism and energy generation, morphogenesis, signal transduction and stress. The yeast cell wall integrity (CWI) pathway, which is very well conserved in other fungi, is the key pathway for the regulation of this adaptive response. In this review, we summarize the current knowledge of the yeast transcriptional program elicited to counterbalance cell wall stress situations, the role of the CWI pathway in the regulation of this program and the importance of the transcriptional input received by other pathways. Modulation of this adaptive response through the CWI pathway by positive and negative transcriptional feedbacks is also discussed. Since all these regulatory mechanisms are well conserved in pathogenic fungi, improving our knowledge about them will have an impact in the developing of new antifungal therapies. PMID:29371494
Source signature estimation from multimode surface waves via mode-separated virtual real source method

NASA Astrophysics Data System (ADS)

Gao, Lingli; Pan, Yudi

2018-05-01

The correct estimation of the seismic source signature is crucial to exploration geophysics. Based on seismic interferometry, the virtual real source (VRS) method provides a model-independent way for source signature estimation. However, when encountering multimode surface waves, which are commonly seen in the shallow seismic survey, strong spurious events appear in seismic interferometric results. These spurious events introduce errors in the virtual-source recordings and reduce the accuracy of the source signature estimated by the VRS method. In order to estimate a correct source signature from multimode surface waves, we propose a mode-separated VRS method. In this method, multimode surface waves are mode separated before seismic interferometry. Virtual-source recordings are then obtained by applying seismic interferometry to each mode individually. Therefore, artefacts caused by cross-mode correlation are excluded in the virtual-source recordings and the estimated source signatures. A synthetic example showed that a correct source signature can be estimated with the proposed method, while strong spurious oscillation occurs in the estimated source signature if we do not apply mode separation first. We also applied the proposed method to a field example, which verified its validity and effectiveness in estimating seismic source signature from shallow seismic shot gathers containing multimode surface waves.
GLINT. Gravitational-wave laser INterferometry triangle

NASA Astrophysics Data System (ADS)

Aria, Shafa; Azevedo, Rui; Burow, Rick; Cahill, Fiachra; Ducheckova, Lada; Holroyd, Alexa; Huarcaya, Victor; Järvelä, Emilia; Koßagk, Martin; Moeckel, Chris; Rodriguez, Ana; Royer, Fabien; Sypniewski, Richard; Vittori, Edoardo; Yttergren, Madeleine

2017-11-01

When the universe was roughly one billion years old, supermassive black holes (103-106 solar masses) already existed. The occurrence of supermassive black holes on such short time scales are poorly understood in terms of their physical or evolutionary processes. Our current understanding is limited by the lack of observational data due the limits of electromagnetic radiation. Gravitational waves as predicted by the theory of general relativity have provided us with the means to probe deeper into the history of the universe. During the ESA Alpach Summer School of 2015, a group of science and engineering students devised GLINT (Gravitational-wave Laser INterferometry Triangle), a space mission concept capable of measuring gravitational waves emitted by black holes that have formed at the early periods after the big bang. Morespecifically at redshifts of 15 < z < 30(˜ 0.1 - 0.3× 109 years after the big bang) in the frequency range 0.01 - 1 Hz. GLINT design strain sensitivity of 5× 10^{-24} 1/√ { {Hz}} will theoretically allow the study of early black holes formations as well as merging events and collapses. The laser interferometry, the technology used for measuring gravitational waves, monitors the separation of test masses in free-fall, where a change of separation indicates the passage of a gravitational wave. The test masses will be shielded from disturbing forces in a constellation of three geocentric orbiting satellites.
Intensity of Cold Water and its effects on marine culturing farms along the southeast coast of Korea

NASA Astrophysics Data System (ADS)

Lee, Yong-Hwa; Shim, JeongHee; Choi, Yang-Ho; Kim, Sang-Woo; Shim, Jeong-Min

2017-04-01

To understand the characteristics and strength of the cold water that has caused damage to marine-culturing farms around Guryongpo, in the southeast coast of Korea, surface and water column temperatures were collected from temperature loggers deployed at a sea squirt farm during August-November 2007 and from a Real-time Information System for aquaculture environments operated by NIFS during July-August 2015 and 2016. During the study period, surface temperature at Guryongpo decreased sharply when south/southwestern winds prevailed (the 18-26th of August and 20-22nd of September 2007 and the 13-15th of July 2015) as a result of upwelling. However, the deep-water (20-30m) temperature increased during periods of strong north/northeasterly winds (the 5-7th and 16-18th of September 2007) as a result of downwelling. Among the cold water events that occurred at Guryongpo, the mass death of cultured fish followed strong cold water events (surface temperatures below 10℃) that were caused by more than two days of successive south/southeastern winds with maximum speeds higher than 5 m/s. A Cold Water Index (CWI) was defined and calculated using maximum wind speed and direction as measured daily at Pohang Meteorological Observatory. When the average CWI over two days (CWI2d) was higher than 100, mass fish mortality occurred. The four-day average CWI (CWI4d) showed a high negative correlation with surface temperature from July-August in the Guryongpo area (R2 = 0.5), suggesting that CWI is a good index for predicting strong cold water events and massive mortality. In October 2007, the sea temperature at a depth of 30 m showed a high fluctuation that ranged from 7-23℃, with frequency and spectrum coinciding with tidal levels at Ulsan, affected by the North Korean Cold Current. If temperature variations at the depth of fish cages also regularly fluctuate within this range, damage may be caused to the fish industry along the southeast coast of Korea.

Digital off-axis holographic interferometry with simulated wavefront.

PubMed

Belashov, A V; Petrov, N V; Semenova, I V

2014-11-17

The paper presents a novel algorithm based on digital holographic interferometry and being promising for evaluation of phase variations from highly noisy or modulated by speckle-structures digital holograms. The suggested algorithm simulates an interferogram in finite width fringes, by analogy with classical double exposure holographic interferometry. Thus obtained interferogram is then processed as a digital hologram. The advantages of the suggested approach are demonstrated in numerical experiments on calculations of differences in phase distributions of wave fronts modulated by speckle structure, as well as in a physical experiment on the analysis of laser-induced heating dynamics of an aqueous solution of a photosensitizer. It is shown that owing to the inherent capability of the approach to perform adjustable smoothing of compared wave fronts, the resulting difference undergoes noise filtering. This capability of adjustable smoothing may be used to minimize losses in spatial resolution. Since the method allows to vary an observation angle of compared wave fields, an opportunity to compensate misalignment of optical axes of these wave fronts arises. This feature can be required, for example, when using two different setups in comparative digital holography or for compensation of recording system displacements during a set of exposures in studies of dynamic processes.
Monitoring stress changes in a concrete bridge with coda wave interferometry.

PubMed

Stähler, Simon Christian; Sens-Schönfelder, Christoph; Niederleithinger, Ernst

2011-04-01

Coda wave interferometry is a recent analysis method now widely used in seismology. It uses the increased sensitivity of multiply scattered elastic waves with long travel-times for monitoring weak changes in a medium. While its application for structural monitoring has been shown to work under laboratory conditions, the usability on a real structure with known material changes had yet to be proven. This article presents experiments on a concrete bridge during construction. The results show that small velocity perturbations induced by a changing stress state in the structure can be determined even under adverse conditions. Theoretical estimations based on the stress calculations by the structural engineers are in good agreement with the measured velocity variations.
Intramuscular temperature changes during and after 2 different cryotherapy interventions in healthy individuals.

PubMed

Rupp, Kimberly A; Herman, Daniel C; Hertel, Jay; Saliba, Susan A

2012-08-01

Crossover. To compare the time required to decrease intramuscular temperature 8°C below baseline temperature, and to compare intramuscular temperature 90 minutes posttreatment, between 2 cryotherapy modalities. Cryotherapy is used to treat pain from muscle injuries. Cooler intramuscular temperatures may reduce cellular metabolism and secondary hypoxic injury to attenuate acute injury response, specifically the rate of chemical mediator activity. Modalities that decrease intramuscular temperature quickly may be beneficial in the treatment of muscle injuries. Eighteen healthy subjects received 2 cryotherapy conditions, crushed-ice bag (CIB) and cold-water immersion (CWI), in a randomly allocated order, separated by 72 hours. Each condition was applied until intramuscular temperature decreased 8°C below baseline. Intramuscular temperature was monitored in the gastrocnemius, 1 cm below subcutaneous adipose tissue. The primary outcome was time to decrease intramuscular temperature 8°C below baseline. A secondary outcome was intramuscular temperature at the end of a 90-minute rewarming period. Paired t tests were used to examine outcomes. Time to reach an 8°C reduction in intramuscular temperature was not significantly different between CIB and CWI (mean difference, 2.6 minutes; 95% confidence interval: -3.10, 8.30). Intramuscular temperature remained significantly colder 90 minutes post-CWI compared to CIB (mean difference, 2.8°C; 95% confidence interval: 2.07°C, 3.52°C). There was no difference in time required to reduce intramuscular temperature 8°C 1 cm below adipose tissue using CIB and CWI. However, intramuscular temperature remained significantly colder 90 minutes following CWI. These results provide clinicians with information that may guide treatment-modality decisions.
Childhood disadvantage and emergency admission rates for common presentations in London: an exploratory analysis.

PubMed

Kyle, Richard G; Kukanova, Marina; Campbell, Malcolm; Wolfe, Ingrid; Powell, Peter; Callery, Peter

2011-03-01

To determine whether emergency hospital admission rates (EAR) for common paediatric conditions in Greater London are associated with measures of child well-being and deprivation. Retrospective analysis of hospital episode statistics and secondary analysis of the Index of Multiple Deprivation (IMD) 2007 and Local Index of Child Well-Being (CWI) 2009. 31 Greater London primary care trusts (PCTs). EAR in PCTs for breathing difficulty, feverish illness and/or diarrhoea. 24,481 children under 15 years of age were discharged following emergency admission for breathing difficulty, feverish illness and/or diarrhoea during 2007/2008. The EAR for breathing difficulty was associated with the IMD (Spearman's rho 0.59, p<0.001) and IMD indicators of: overcrowding (Spearman's rho 0.62, p<0.001), houses in poor condition (Spearman's rho 0.55, p=0.001), air quality (Spearman's rho 0.53, p=0.002), homelessness (Spearman's rho 0.44, p=0.013), and domains of the CWI: housing (Spearman's rho 0.64, p<0.001), children in need (Spearman's rho 0.62, p<0.001), material (Spearman's rho 0.58, p=0.001) and environment (Spearman's rho 0.53, p=0.002). There were no statistically significant relationships between the EAR of children admitted for feverish illness and diarrhoea or aged under 1 year for any condition, and the IMD, either IMD indicators or CWI domains. Housing and environmental factors are associated with children's demand for hospital admission for breathing difficulty. Some associations are stronger with the CWI than the IMD. The CWI has potential to identify priority PCTs for housing and environment interventions that could have specific public health benefits for respiratory conditions.
Cold-Water Immersion and Contrast Water Therapy: No Improvement of Short-Term Recovery After Resistance Training.

PubMed

Argus, Christos K; Broatch, James R; Petersen, Aaron C; Polman, Remco; Bishop, David J; Halson, Shona

2017-08-01

An athlete's ability to recover quickly is important when there is limited time between training and competition. As such, recovery strategies are commonly used to expedite the recovery process. To determine the effectiveness of both cold-water immersion (CWI) and contrast water therapy (CWT) compared with control on short-term recovery (<4 h) after a single full-body resistance-training session. Thirteen men (age 26 ± 5 y, weight 79 ± 7 kg, height 177 ± 5 cm) were assessed for perceptual (fatigue and soreness) and performance measures (maximal voluntary isometric contraction [MVC] of the knee extensors, weighted and unweighted countermovement jumps) before and immediately after the training session. Subjects then completed 1 of three 14-min recovery strategies (CWI, CWT, or passive sitting [CON]), with the perceptual and performance measures reassessed immediately, 2 h, and 4 h postrecovery. Peak torque during MVC and jump performance were significantly decreased (P < .05) after the resistance-training session and remained depressed for at least 4 h postrecovery in all conditions. Neither CWI nor CWT had any effect on perceptual or performance measures over the 4-h recovery period. CWI and CWT did not improve short-term (<4-h) recovery after a conventional resistance-training session.
Testing the effect of computer-generated hologram fabrication error in a cylindrical interferometry system

NASA Astrophysics Data System (ADS)

Wang, Qingquan; Yu, Yingjie; Mou, Kebing

2017-10-01

This paper presents a method of testing the effect of computer-generated hologram (CGH) fabrication error in a cylindrical interferometry system. An experimental system is developed for calibrating the effect of this error. In the calibrating system, a mirror with high surface accuracy is placed at the focal axis of the cylindrical wave. After transmitting through the CGH, the reflected cylindrical wave can be transformed into a plane wave again, and then the plane wave interferes with the reference plane wave. Finally, the double-pass transmitted wavefront of the CGH, representing the effect of the CGH fabrication error in the experimental system, is obtained by analyzing the interferogram. The mathematical model of misalignment aberration removal in the calibration system is described, and the feasibility is demonstrated via the simulation system established in Zemax. With the mathematical polynomial, most of the possible misalignment errors can be estimated with the least-squares fitting algorithm, and then the double-pass transmitted wavefront of the CGH can be obtained by subtracting the misalignment errors from the result extracted from the real experimental system. Compared to the standard double-pass transmitted wavefront given by Diffraction International Ltd., which manufactured the CGH used in the experimental system, the result is desirable. We conclude that the proposed method is effective in calibrating the effect of the CGH error in the cylindrical interferometry system for the measurement of cylindricity error.
Near-field interferometry of a free-falling nanoparticle from a point-like source

NASA Astrophysics Data System (ADS)

Bateman, James; Nimmrichter, Stefan; Hornberger, Klaus; Ulbricht, Hendrik

2014-09-01

Matter-wave interferometry performed with massive objects elucidates their wave nature and thus tests the quantum superposition principle at large scales. Whereas standard quantum theory places no limit on particle size, alternative, yet untested theories—conceived to explain the apparent quantum to classical transition—forbid macroscopic superpositions. Here we propose an interferometer with a levitated, optically cooled and then free-falling silicon nanoparticle in the mass range of one million atomic mass units, delocalized over >150 nm. The scheme employs the near-field Talbot effect with a single standing-wave laser pulse as a phase grating. Our analysis, which accounts for all relevant sources of decoherence, indicates that this is a viable route towards macroscopic high-mass superpositions using available technology.
Effectiveness and safety of continuous wound infiltration for postoperative pain management after open gastrectomy

PubMed Central

Zheng, Xing; Feng, Xu; Cai, Xiu-Jun

2016-01-01

AIM: To prospectively evaluate the effectiveness and safety of continuous wound infiltration (CWI) for pain management after open gastrectomy. METHODS: Seventy-five adult patients with American Society of Anesthesiologists (ASA) Physical Status Classification System (ASA) grade 1-3 undergoing open gastrectomy were randomized to three groups. Group 1 patients received CWI with 0.3% ropivacaine (group CWI). Group 2 patients received 0.5 mg/mL morphine intravenously by a patient-controlled analgesia pump (PCIA) (group PCIA). Group 3 patients received epidural analgesia (EA) with 0.12% ropivacaine and 20 µg/mL morphine with an infusion at 6-8 mL/h for 48 h (group EA). A standard general anesthetic technique was used for all three groups. Rescue analgesia (2 mg bolus of morphine, intravenous) was given when the visual analogue scale (VAS) score was ≥ 4. The outcomes measured over 48 h after the operation were VAS scores both at rest and during mobilization, total morphine consumption, relative side effects, and basic vital signs. Further results including time to extubation, recovery of bowel function, surgical wound healing, mean length of hospitalization after surgery, and the patient’s satisfaction were also recorded. RESULTS: All three groups had similar VAS scores during the first 48 h after surgery. Group CWI and group EA, compared with group PCIA, had lower morphine consumption (P < 0.001), less postoperative nausea and vomiting (1.20 ± 0.41 vs 1.96 ± 0.67, 1.32 ± 0.56 vs 1.96 ± 0.67, respectively, P < 0.001), earlier extubation (16.56 ± 5.24 min vs 19.76 ± 5.75 min, P < 0.05, 15.48 ± 4.59 min vs 19.76 ± 5.75 min, P < 0.01), and earlier recovery of bowel function (2.96 ± 1.17 d vs 3.60 ± 1.04 d, 2.80 ± 1.38 d vs 3.60 ± 1.04 d, respectively, P < 0.05). The mean length of hospitalization after surgery was reduced in groups CWI (8.20 ± 2.58 d vs 10.08 ± 3.15 d, P < 0.05) and EA (7.96 ± 2.30 d vs 10.08 ± 3.15 d, P < 0.01) compared with group PCIA. All three groups had similar patient satisfaction and wound healing, but group PCIA was prone to higher sedation scores when compared with groups CWI and EA, especially during the first 12 h after surgery. Group EA had a lower mean arterial pressure within the first postoperative 12 h compared with the other two groups. CONCLUSION: CWI with ropivacaine yields a satisfactory analgesic effect within the first 48 h after open gastrectomy, with lower morphine consumption and accelerated recovery. PMID:26855550
Lunar Structure from Coda Wave Interferometry

NASA Astrophysics Data System (ADS)

Nunn, Ceri; Igel, Heiner

2017-04-01

As part of the Apollo lunar missions, four seismometers were deployed on the near-side of the Moon between 1969 and 1972, and operated continuously until 1977. There are many difficulties associated with determining lunar structure from these records. As a result, many properties of the moon, such as the thickness, density and porosity of the crust are poorly constrained. This hampers our ability to determine the structure, geochemical composition of the moon, its evolution, and ultimately the evolution of the solar system. We explore the use of coda wave interferometry to reconstruct the near surface structure within the strongly scattering lunar crust.
Radio interferometry: Techniques for Geodesy. [conference

NASA Technical Reports Server (NTRS)

1980-01-01

Progress in the development and application of radio interferometry as a tool for geophysical research is reported and discussed. Among the topics reviewed are: Surveys of is the Seventies, Movements, Terrestrial and Celestial, Degrees Kelvin and Degrees of Phase, the Mark 3 VLBI System, Waves of the Future and other Emissions, and Adherence and Coherence in Networks, and Plans.
Measurement of spatio-temporal field distribution of THz pulses in electro-optic crystal by interferometry method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chizhov, P A; Ushakov, A A; Bukin, V V

2015-05-31

We propose a scheme for measuring the spatial distribution of the THz pulse electric field strength in an electro-optic crystal using optical interferometry. The resulting images of the field distribution from a test source with a spherical wave front are presented. (extreme light fields and their applications)
Comparison of between-training-sessions recovery strategies for world-class BMX pilots.

PubMed

Marquet, Laurie-Anne; Hausswirth, Christophe; Hays, Arnaud; Vettoretti, Fabrice; Brisswalter, Jeanick

2015-03-01

To assess the impact of between-training-sessions recovery strategies (passive [PAS], active [ACT], cold-water immersion [CWI], and ingestion of a recovery drink [NUTR]) on maximal cycling performance, perceptions of delayed-onset muscle soreness (DOMS), and fatigue in world-class BMX riders. Eleven elite BMX athletes, members of the French national team (top country in the 2011 international ranking, 4 medals at the 2012 World Championships, top European country), participated in the study, which involved standardized training periods. Athletes performed 3 maximal-sprint power tests: the first day of the week before the training session and before and after training on the third day of the week (D3). The recovery strategy was randomly assigned to each participant on day 2 immediately after the last training period of the day. Perceptions of DOMS and general fatigue were recorded on D3. After training on D3, the decrease in maximal-sprint power (Pmax) was significantly greater for PAS than with CWI (P=.02) and NUTR (P=.018). Similar results were found with ACT (vs CWI P=.044, and vs NUTR P=.042). Self-reported DOMS and fatigue were significantly greater after PAS than after other strategies. For elite BMX riders, between training days, nutritional and/or CWI recovery strategies appear to be best for reducing muscle fatigue and increasing the capacity to withstand the training schedule.
Ultra-sensitive inertial sensors via neutral-atom interferometry

NASA Technical Reports Server (NTRS)

Clauser, John F.

1989-01-01

Upon looking at the various colossal interferometers, etc., discussed at this conference to test gravitational theory, one cannot avoid feeling that easier approaches exist. The use of low velocity, neutral atom matter waves in place of electromagnetic waves in sensitive inertial interferometer configurations is proposed. For applications, spacecraft experiments to sense a drag-free condition, to measure the Lense-Thirring precession, to measure the gravitomagnetic effect and/or the earth's geopotential (depending on altitude), and to detect long period gravitational waves are considered. Also, a terrestrial precision test of the equivalence principle on spin polarized atoms, capable of detecting effects of the 5th force is considered. While the ideas described herein are preliminary, the orders of magnitude are sufficiently tantalizing to warrant further study. Although existing proposed designs may be adequate for some of these experiments, the use of matter-wave interferometry offers reduced complexity and cost, and an absence of cryogenics.
Monitoring localized cracks on under pressure concrete nuclear containment wall using linear and nonlinear ultrasonic coda wave interferometry

NASA Astrophysics Data System (ADS)

Legland, J.-B.; Abraham, O.; Durand, O.; Henault, J.-M.

2018-04-01

Civil engineering is constantly demanding new methods for evaluation and non-destructive testing (NDT), particularly to prevent and monitor serious damage to concrete structures. Tn this work, experimental results are presented on the detection and characterization of cracks using nonlinear modulation of coda waves interferometry (NCWT) [1]. This method consists in mixing high-amplitude low-frequency acoustic waves with multi-scattered probe waves (coda) and analyzing their effects by interferometry. Unlike the classic method of coda analysis (CWT), the NCWT does not require the recording of a coda as a reference before damage to the structure. Tn the framework of the PTA-ENDE project, a 1/3 model of a preconstrained concrete containment (EDF VeRCoRs mock-up) is placed under pressure to study the leakage of the structure. During this evaluation protocol, specific areas are monitored by the NCWT (during 5 days, which correspond to the protocol of nuclear power plant pressurization under maintenance test). The acoustic nonlinear response due to the high amplitude of the acoustic modulation gives pertinent information about the elastic and dissipative nonlinearities of the concrete. Tts effective level is evaluated by two nonlinear observables extracted from the interferometry. The increase of nonlinearities is in agreement with the creation of a crack with a network of microcracks located at its base; however, a change in the dynamics of the evolution of the nonlinearities may indicate the opening of a through crack. Tn addition, as during the experimental campaign, reference codas have been recorded. We used CWT to follow the stress evolution and the gas leaks ratio of the structure. Both CWT and NCWT results are presented in this paper.
Doppler synthetic aperture radar interferometry: a novel SAR interferometry for height mapping using ultra-narrowband waveforms

NASA Astrophysics Data System (ADS)

Yazıcı, Birsen; Son, Il-Young; Cagri Yanik, H.

2018-05-01

This paper introduces a new and novel radar interferometry based on Doppler synthetic aperture radar (Doppler-SAR) paradigm. Conventional SAR interferometry relies on wideband transmitted waveforms to obtain high range resolution. Topography of a surface is directly related to the range difference between two antennas configured at different positions. Doppler-SAR is a novel imaging modality that uses ultra-narrowband continuous waves (UNCW). It takes advantage of high resolution Doppler information provided by UNCWs to form high resolution SAR images. We introduce the theory of Doppler-SAR interferometry. We derive an interferometric phase model and develop the equations of height mapping. Unlike conventional SAR interferometry, we show that the topography of a scene is related to the difference in Doppler frequency between two antennas configured at different velocities. While the conventional SAR interferometry uses range, Doppler and Doppler due to interferometric phase in height mapping; Doppler-SAR interferometry uses Doppler, Doppler-rate and Doppler-rate due to interferometric phase in height mapping. We demonstrate our theory in numerical simulations. Doppler-SAR interferometry offers the advantages of long-range, robust, environmentally friendly operations; low-power, low-cost, lightweight systems suitable for low-payload platforms, such as micro-satellites; and passive applications using sources of opportunity transmitting UNCW.
Continuous wound infiltration or epidural analgesia for pain prevention after hepato-pancreato-biliary surgery within an enhanced recovery program (POP-UP trial): study protocol for a randomized controlled trial.

PubMed

Mungroop, Timothy H; Veelo, Denise P; Busch, Olivier R; van Dieren, Susan; van Gulik, Thomas M; Karsten, Tom M; de Castro, Steve M; Godfried, Marc B; Thiel, Bram; Hollmann, Markus W; Lirk, Philipp; Besselink, Marc G

2015-12-09

Postoperative pain prevention is essential for the recovery of surgical patients. Continuous (thoracic) epidural analgesia (CEA) is routinely practiced for major abdominal surgery, but evidence is conflicting on its benefits in this setting. Potential disadvantages of epidural analgesia are a) perioperative hypotension, frequently requiring additional intravenous fluid boluses or prolonged use of vasopressors; b) relatively high failure rates, with periods of inadequate analgesia; and c) the risk of rare but serious, at times persistent, neurologic complications (hematoma and abscess). In recent years, continuous (subfascial) wound infiltration (CWI) plus patient-controlled analgesia (PCA) has been suggested as a safe and reliable alternative, which does not have the previously mentioned disadvantages, but evidence from multicenter trials targeting a specific surgical population is lacking. We hypothesize that CWI+PCA is equally as effective as CEA, without the mentioned disadvantages. POP-UP is a randomized controlled noninferiority multicenter trial, recruiting adult patients scheduled for elective hepato-pancreato-biliary surgery via laparotomy in an enhanced recovery setting. A total of 102 patients are being randomly allocated to CWI+PCA or (P)CEA. Our primary endpoint is the Overall Benefit of Analgesic Score (OBAS), a composite endpoint of pain intensity, opioid-related adverse effects and patient satisfaction, during postoperative days 1 to 5. Secondary endpoints include length of the hospital stay, number of patients with severe pain, and the use of rescue medication. POP-UP is a pragmatic trial that will provide evidence of whether CWI+PCA is noninferior as compared to (P)CEA after elective hepato-pancreato-biliary surgery via laparotomy in an enhanced recovery setting. If this hypothesis is confirmed, this finding could contribute to more widespread implementation of this technique, especially when the described disadvantages of epidural analgesia are less often observed with CWI+PCA. Netherlands Trial Register NTR4948 (registry date 2 January 2015).
Influence of cold-water immersion on recovery of elite triathletes following the ironman world championship.

PubMed

Stearns, Rebecca L; Nolan, Julie K; Huggins, Robert A; Maresh, Carl M; Munõz, Colleen X; Pagnotta, Kelly D; Volk, Brittanie M; Casa, Douglas J

2018-01-31

Cold water immersion (CWI) has been widely used for enhancing athlete recovery though its use following an Ironman triathlon has never been examined. The purpose of this paper is to determine the influence of CWI immediately following an Ironman triathlon on markers of muscle damage, inflammation and muscle soreness. Prospective cohort study. Thirty three (22 male, 11 female), triathletes participating in the Ironman World Championships volunteered to participate (mean±SD: age=40±11years; height=174.5±9.1cm; body mass=70±11.8kg; percent body fat=11.4±4.1%, finish time=11:03.00±01:25.08). Post race, participants were randomly assigned to a 10-min bout of 10°C CWI or no-intervention control group. Data collection occurred pre-intervention (PRE), post-intervention (POST), 16h (16POST) and 40h (40POST) following the race. Linear mixed model ANOVA with Bonferroni corrections were performed to examine group by time differences for delayed onset muscle soreness (DOMS), hydration indices, myoglobin, creatine kinase (CK), cortisol, C-reactive protein (CRP), IL-6 and percent body mass loss (%BML). Pearson's bivariate correlations were used for comparisons with finishing time. Alpha level was set a priori at 0.05. No significant group by time interactions occurred. Significant differences occurred for POST BML (-1.7±0.9kg) vs. 16POST, and 40POST BML (0.9±1.4, -0.1±1.2kg, respectively; p<0.001). Compared to PRE, myoglobin, CRP and CK remained significantly elevated at 40POST. Cortisol returned to PRE values by 16POST and IL-6 returned to PRE values by 40POST. A single bout of CWI did not provide any physiological benefit during recovery from a triathlon within 40h post race. Effect of CWI beyond this time is unknown. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Acute response to hydrotherapy after a simulated game of rugby.

PubMed

Higgins, Trevor R; Cameron, Melainie L; Climstein, Mike

2013-10-01

Despite lacking clear scientific evidence, hydrotherapies (water treatments) are accepted techniques to help team sport athletes recover from the physical effects of games. The purpose of this study was to assess the comparative effectiveness of cold water immersions (CWIs) and hot-and-cold contrast baths on athletes' recovery after a simulated game of rugby union. Twenty-four experienced, well-trained, male rugby union players were divided into 3 groups to receive recovery interventions: CWI for 1 group, contrast baths for a second group, and passive recovery for a third (control) group. Pregame and postgame measurements included a countermovement jump (normalized as a ratio to body weight), a sit-and-stretch flexibility test (centimeters), thigh circumference (to detect swelling; centimeters), and participants' perception of delayed-onset muscular soreness (DOMS, 100-mm visual analog scale). Statistical analysis included analysis of variance, and the calculation of omnibus effect sizes for each group ((Equation is included in full-text article.)) and the magnitudes of change within and between groups (Cohen's d). The participants in the contrast bath group reported statistically significantly greater measures of DOMS than participants in the control group did at 1 hour postintervention (p = 0.05, control group: d = 1.80; contrast bath: d = 4.75), and than participants in the CWI group did at 48 hours postintervention (p = 0.02, CWI: d = 1.17; contrast bath: d = 1.97). These findings provide modest evidence that contrast baths are a less effective strategy for recovery from rugby union than are CWI or passive recovery. Specifically, 2 × 5-minute CWI is superior to both contrasts baths and passive recovery in alleviating DOMS after exercise-induced muscle damage. Our recommendation for rugby union players aiming to attenuate the effects of DOMS postgames is to take 2 × 5-minute CWIs baths immediately after the game.
Far infrared diagnostics of electron concentration in combustion MHD plasmas using interferometry and Faraday rotation

NASA Astrophysics Data System (ADS)

Kuzmenko, P. J.

1985-12-01

The plasma electrical conductivity is a key parameter in determining the efficiency of an magnetohydrodynamic (MHD) generator. Electromagnetic waves offer an accurate, non-intrusive probe. The electron concentration and mobility may be deduced from the refractive index and absorption coefficient measured with an interferometer. The first experiment used an HCOOH laser at 393.6 microns feeding a Michelson interferometer mounted around a combustor duct with open ports. Simultaneous measurements of positive ion density and plasma temperature made with a Langmuir probe and line reversal apparatus verified the operation of the interferometer. With a magnetic field present, measurement of the polarization rotation and induced ellipticity in a wave traveling along the field provides information on the plasma conductivity. Compared to interferometry, diagnostic apparatus based on Faraday rotation offers simpler optics and requires far less stringent mechanical stability at a cost of lower sensitivity. An advanced detection scheme, using a polarizing beam splitter improved the sensitivity to be comparable to that of interferometry. Interferometry is the preferred technique for small scale, high accuracy measurements, with Faraday rotation reserved for large systems or measurements within a working generator.
Coda Wave Interferometry Method Applied in Structural Monitoring to Assess Damage Evolution in Masonry and Concrete Structures

NASA Astrophysics Data System (ADS)

Masera, D.; Bocca, P.; Grazzini, A.

2011-07-01

In this experimental program the main goal is to monitor the damage evolution in masonry and concrete structures by Acoustic Emission (AE) signal analysis applying a well-know seismic method. For this reason the concept of the coda wave interferometry is applied to AE signal recorded during the tests. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced masonry walls under variable amplitude loading and strengthening reinforced concrete (RC) beams under monotonic static load has been carried out. In the reinforced masonry wall, cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of masonry under static long-time loading. During the tests, the evaluation of fracture growth is monitored by coda wave interferometry which represents a novel approach in structural monitoring based on AE relative change velocity of coda signal. In general, the sensitivity of coda waves has been used to estimate velocity changes in fault zones, in volcanoes, in a mining environment, and in ultrasound experiments. This method uses multiple scattered waves, which travelled through the material along numerous paths, to infer tiny temporal changes in the wave velocity. The applied method has the potential to be used as a "damage-gauge" for monitoring velocity changes as a sign of damage evolution into masonry and concrete structures.

Ideal-observer detectability in photon-counting differential phase-contrast imaging using a linear-systems approach

PubMed Central

Fredenberg, Erik; Danielsson, Mats; Stayman, J. Webster; Siewerdsen, Jeffrey H.; Åslund, Magnus

2012-01-01

Purpose: To provide a cascaded-systems framework based on the noise-power spectrum (NPS), modulation transfer function (MTF), and noise-equivalent number of quanta (NEQ) for quantitative evaluation of differential phase-contrast imaging (Talbot interferometry) in relation to conventional absorption contrast under equal-dose, equal-geometry, and, to some extent, equal-photon-economy constraints. The focus is a geometry for photon-counting mammography. Methods: Phase-contrast imaging is a promising technology that may emerge as an alternative or adjunct to conventional absorption contrast. In particular, phase contrast may increase the signal-difference-to-noise ratio compared to absorption contrast because the difference in phase shift between soft-tissue structures is often substantially larger than the absorption difference. We have developed a comprehensive cascaded-systems framework to investigate Talbot interferometry, which is a technique for differential phase-contrast imaging. Analytical expressions for the MTF and NPS were derived to calculate the NEQ and a task-specific ideal-observer detectability index under assumptions of linearity and shift invariance. Talbot interferometry was compared to absorption contrast at equal dose, and using either a plane wave or a spherical wave in a conceivable mammography geometry. The impact of source size and spectrum bandwidth was included in the framework, and the trade-off with photon economy was investigated in some detail. Wave-propagation simulations were used to verify the analytical expressions and to generate example images. Results: Talbot interferometry inherently detects the differential of the phase, which led to a maximum in NEQ at high spatial frequencies, whereas the absorption-contrast NEQ decreased monotonically with frequency. Further, phase contrast detects differences in density rather than atomic number, and the optimal imaging energy was found to be a factor of 1.7 higher than for absorption contrast. Talbot interferometry with a plane wave increased detectability for 0.1-mm tumor and glandular structures by a factor of 3–4 at equal dose, whereas absorption contrast was the preferred method for structures larger than ∼0.5 mm. Microcalcifications are small, but differ from soft tissue in atomic number more than density, which is favored by absorption contrast, and Talbot interferometry was barely beneficial at all within the resolution limit of the system. Further, Talbot interferometry favored detection of “sharp” as opposed to “smooth” structures, and discrimination tasks by about 50% compared to detection tasks. The technique was relatively insensitive to spectrum bandwidth, whereas the projected source size was more important. If equal photon economy was added as a restriction, phase-contrast efficiency was reduced so that the benefit for detection tasks almost vanished compared to absorption contrast, but discrimination tasks were still improved close to a factor of 2 at the resolution limit. Conclusions: Cascaded-systems analysis enables comprehensive and intuitive evaluation of phase-contrast efficiency in relation to absorption contrast under requirements of equal dose, equal geometry, and equal photon economy. The benefit of Talbot interferometry was highly dependent on task, in particular detection versus discrimination tasks, and target size, shape, and material. Requiring equal photon economy weakened the benefit of Talbot interferometry in mammography. PMID:22957600
Ultrafast dynamic response of single crystal β-HMX

NASA Astrophysics Data System (ADS)

Zaug, Joseph M.; Armstrong, Michael R.; Crowhurst, Jonathan C.; Radousky, Harry B.; Ferranti, Louis; Swan, Raymond; Gross, Rick; Teslich, Nick E.; Wall, Mark A.; Austin, Ryan A.; Fried, Laurence E.

2017-01-01

We report results from ultrafast compression experiments conducted on β-HMX single crystals. Results consist of nominally 12 picosecond time-resolved wave profile data, (ultrafast time domain interferometry -TDI measurements), that were analyzed to determine high-velocity wave speeds as a function of piston velocity. TDI results are used to validate calculations of anisotropic stress-strain behavior of shocked loaded energetic materials. Our previous results derived using a 350 ps duration compression drive revealed anisotropic elastic wave response in single crystal β-HMX from (110) and (010) impact planes. Here we present results using a 1.05 ns duration compression drive with a 950 ps interferometry window to extend knowledge of the anisotropic dynamic response of β-HMX within eight microns of the initial impact plane. We observe two distinct wave profiles from (010) and three wave profiles from (010) impact planes. The (110) impact plane wave speeds typically exceed (010) impact plane wave speeds at the same piston velocities. The development of multiple hydrodynamic wave profiles begins at 20 GPa for the (110) impact plane and 28 GPa for the (10) impact plane. We compare our ultrafast TDI results with previous gun and plate impact results on β-HMX and PBX9501.
New Frontiers at the Interface of General Relativity and Quantum Optics

NASA Astrophysics Data System (ADS)

Feiler, C.; Buser, M.; Kajari, E.; Schleich, W. P.; Rasel, E. M.; O'Connell, R. F.

2009-12-01

In the present paper we follow three major themes: (i) concepts of rotation in general relativity, (ii) effects induced by these generalized rotations, and (iii) their measurement using interferometry. Our journey takes us from the Foucault pendulum via the Sagnac interferometer to manifestations of gravito-magnetism in double binary pulsars and in Gödel’s Universe. Throughout our article we emphasize the emerging role of matter wave interferometry based on cold atoms or Bose-Einstein condensates leading to superior inertial sensors. In particular, we advertise recent activities directed towards the operation of a coherent matter wave interferometer in an extended free fall.
Lunar Structure from Ambient Noise and Coda Wave Interferometry

NASA Astrophysics Data System (ADS)

Nunn, C.; Igel, H.

2016-12-01

As part of the Apollo lunar missions, four seismometers were deployed on the near-side of the Moon between 1969 and 1972, and operated continuously until 1977. There are many difficulties associated with determining lunar structure from these records. As a result, many properties of the moon, such as the thickness, density and porosity of the crust are poorly constrained. This hampers our ability to determine the structure, geochemical composition of the moon, its evolution, and ultimately the evolution of the solar system. We explore the use of ambient noise and coda wave interferometry to reconstruct the near surface structure within the strongly scattering lunar crust.
Measurement of fluid properties using rapid-double-exposure and time-average holographic interferometry

NASA Technical Reports Server (NTRS)

Decker, A. J.

1984-01-01

The holographic recording of the time history of a flow feature in three dimensions is discussed. The use of diffuse illumination holographic interferometry or the three dimensional visualization of flow features such as shock waves and turbulent eddies is described. The double-exposure and time-average methods are compared using the characteristic function and the results from a flow simulator. A time history requires a large hologram recording rate. Results of holographic cinematography of the shock waves in a flutter cascade are presented as an example. Future directions of this effort, including the availability and development of suitable lasers, are discussed.
Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

PubMed Central

Levin, David E.

2011-01-01

The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to the Rho1 GTPase, which mobilizes a physiologic response through a variety of effectors. Activation of CWI signaling regulates the production of various carbohydrate polymers of the cell wall, as well as their polarized delivery to the site of cell wall remodeling. This review article centers on CWI signaling in Saccharomyces cerevisiae through the cell cycle and in response to cell wall stress. The interface of this signaling pathway with other pathways that contribute to the maintenance of cell wall integrity is also discussed. PMID:22174182
Monitoring the tidal response of a sea levee with ambient seismic noise

NASA Astrophysics Data System (ADS)

Planès, Thomas; Rittgers, Justin B.; Mooney, Michael A.; Kanning, Wim; Draganov, Deyan

2017-03-01

Internal erosion, a major cause of failure of earthen dams and levees, is often difficult to detect at early stages using traditional visual inspection. The passive seismic-interferometry technique could enable the early detection of internal changes taking place within these structures. We test this technique on a portion of the sea levee of Colijnsplaat, Netherlands, which presents signs of concentrated seepage in the form of sandboils. Applying seismic interferometry to ambient noise collected over a 12-hour period, we retrieve surface waves propagating along the levee. We identify the contribution of two dominant ambient seismic noise sources: the traffic on the Zeeland bridge and a nearby wind turbine. Here, the sea-wave action does not constitute a suitable noise source for seismic interferometry. Using the retrieved surface waves, we compute time-lapse variations of the surface-wave group velocities during the 12-hour tidal cycle for different frequency bands, i.e., for different depth ranges. The estimated group-velocity variations correlate with variations in on-site pore-water pressure measurements that respond to tidal loading. We present lateral profiles of these group-velocity variations along a 180-meter section of the levee, at four different depth ranges (0m-40m). On these profiles, we observe some spatially localized relative group-velocity variations of up to 5% that might be related to concentrated seepage.
Seismic interferometry by crosscorrelation and by multidimensional deconvolution: a systematic comparison

NASA Astrophysics Data System (ADS)

Wapenaar, Kees; van der Neut, Joost; Ruigrok, Elmer; Draganov, Deyan; Hunziker, Juerg; Slob, Evert; Thorbecke, Jan; Snieder, Roel

2010-05-01

In recent years, seismic interferometry (or Green's function retrieval) has led to many applications in seismology (exploration, regional and global), underwater acoustics and ultrasonics. One of the explanations for this broad interest lies in the simplicity of the methodology. In passive data applications a simple crosscorrelation of responses at two receivers gives the impulse response (Green's function) at one receiver as if there were a source at the position of the other. In controlled-source applications the procedure is similar, except that it involves in addition a summation along the sources. It has also been recognized that the simple crosscorrelation approach has its limitations. From the various theoretical models it follows that there are a number of underlying assumptions for retrieving the Green's function by crosscorrelation. The most important assumptions are that the medium is lossless and that the waves are equipartitioned. In heuristic terms the latter condition means that the receivers are illuminated isotropically from all directions, which is for example achieved when the sources are regularly distributed along a closed surface, the sources are mutually uncorrelated and their power spectra are identical. Despite the fact that in practical situations these conditions are at most only partly fulfilled, the results of seismic interferometry are generally quite robust, but the retrieved amplitudes are unreliable and the results are often blurred by artifacts. Several researchers have proposed to address some of the shortcomings by replacing the correlation process by deconvolution. In most cases the employed deconvolution procedure is essentially 1-D (i.e., trace-by-trace deconvolution). This compensates the anelastic losses, but it does not account for the anisotropic illumination of the receivers. To obtain more accurate results, seismic interferometry by deconvolution should acknowledge the 3-D nature of the seismic wave field. Hence, from a theoretical point of view, the trace-by-trace process should be replaced by a full 3-D wave field deconvolution process. Interferometry by multidimensional deconvolution is more accurate than the trace-by-trace correlation and deconvolution approaches but the processing is more involved. In the presentation we will give a systematic analysis of seismic interferometry by crosscorrelation versus multi-dimensional deconvolution and discuss applications of both approaches.
A multidisciplinary study of planetary, solar and astrophysical radio emissions

NASA Technical Reports Server (NTRS)

Gurnett, D. A.; Calvert, W.; Fielder, R.; Goertz, C.; Grabbe, C.; Kurth, W.; Mutel, R.; Sheerin, J.; Mellott, M.; Spangler, S.

1986-01-01

Combination of the related fields of planetary, solar, and astrophysical radio emissions was attempted in order to more fully understand the radio emission processes. Topics addressed include: remote sensing of astrophysical plasma turbulence; Alfven waves; astrophysical shock waves; surface waves; very long base interferometry results; very large array observations; solar magnetic flux; and magnetohydrodynamic waves as a tool for solar corona diagnostics.
Thermal Cracking in Westerly Granite Monitored Using Direct Wave Velocity, Coda Wave Interferometry, and Acoustic Emissions

NASA Astrophysics Data System (ADS)

Griffiths, L.; Lengliné, O.; Heap, M. J.; Baud, P.; Schmittbuhl, J.

2018-03-01

To monitor both the permanent (thermal microcracking) and the nonpermanent (thermo-elastic) effects of temperature on Westerly Granite, we combine acoustic emission monitoring and ultrasonic velocity measurements at ambient pressure during three heating and cooling cycles to a maximum temperature of 450°C. For the velocity measurements we use both P wave direct traveltime and coda wave interferometry techniques, the latter being more sensitive to changes in S wave velocity. During the first cycle, we observe a high acoustic emission rate and large—and mostly permanent—apparent reductions in velocity with temperature (P wave velocity is reduced by 50% of the initial value at 450°C, and 40% upon cooling). Our measurements are indicative of extensive thermal microcracking during the first cycle, predominantly during the heating phase. During the second cycle we observe further—but reduced—microcracking, and less still during the third cycle, where the apparent decrease in velocity with temperature is near reversible (at 450°C, the P wave velocity is decreased by roughly 10% of the initial velocity). Our results, relevant for thermally dynamic environments such as geothermal reservoirs, highlight the value of performing measurements of rock properties under in situ temperature conditions.
Analysis of standing sound waves using holographic interferometry

NASA Astrophysics Data System (ADS)

Russell, Daniel A.; Parker, David E.; Hughes, Russell S.

2009-08-01

Optical holographic interferometry was used to study standing sound waves in air inside a resonance tube driven by a small loudspeaker at one end. The front face of the resonance tube was constructed with plexiglass, allowing optical interrogation of the tube interior. The object beam of the holographic setup was directed through the plexiglass and reflected off the back wall of the resonator. When driven at resonance, the fluctuations in the air density at the antinodes altered the refractive index of the air in the tube, causing interference patterns in the resulting holographic images. Real-time holography was used to determine resonance frequencies and to measure the wavelengths of the standing waves. Time-average holography was used to observe the effect of increasing the sound pressure level on the resulting fringe pattern. A simple theory was developed to successfully predict the fringe pattern.
Isotope-selective high-order interferometry with large organic molecules in free fall

NASA Astrophysics Data System (ADS)

Rodewald, Jonas; Dörre, Nadine; Grimaldi, Andrea; Geyer, Philipp; Felix, Lukas; Mayor, Marcel; Shayeghi, Armin; Arndt, Markus

2018-03-01

Interferometry in the time domain has proven valuable for matter-wave based measurements. This concept has recently been generalized to cold molecular clusters using short-pulse standing light waves which realized photo-depletion gratings, arranged in a time-domain Talbot–Lau interferometer (OTIMA). Here we extend this idea further to large organic molecules and demonstrate a new scheme to scan the emerging molecular interferogram in position space. The capability of analyzing different isotopes of the same monomer under identical conditions opens perspectives for studying the interference fringe shift as a function of time in gravitational free fall. The universality of OTIMA interferometry allows one to handle a large variety of particles. In our present work, quasi-continuous laser evaporation allows transferring fragile organic molecules into the gas phase, covering more than an order of magnitude in mass between 614 amu and 6509 amu, i.e. 300% more massive than in previous OTIMA experiments. For all masses, we find about 30% fringe visibility.
Local earthquake interferometry of the IRIS Community Wavefield Experiment, Grant County, Oklahoma

NASA Astrophysics Data System (ADS)

Eddy, A. C.; Harder, S. H.

2017-12-01

The IRIS Community Wavefield Experiment was deployed in Grant County, located in north central Oklahoma, from June 21 to July 27, 2016. Data from all nodes were recorded at 250 samples per second between June 21 and July 20 along three lines. The main line was 12.5 km long oriented east-west and consisted of 129 nodes. The other two lines were 5.5 km long north-south oriented with 49 nodes each. During this time, approximately 150 earthquakes of magnitude 1.0 to 4.4 were recorded in the surrounding counties of Oklahoma and Kansas. Ideally, sources for local earthquake interferometry should be near surface events that produce high frequency body waves. Unlike ambient noise seismic interferometry (ANSI), which uses days, weeks, or even months of continuously recorded seismic data, local earthquake interferometry uses only short segments ( 2 min.) of data. Interferometry in this case is based on the cross-correlation of body wave surface multiples where the event source is translated to a reference station in the array, which acts as a virtual source. Multiples recorded between the reference station and all other stations can be cross-correlated to produce a clear seismic trace. This process will be repeated with every node acting as the reference station for all events. The resulting shot gather will then be processed and analyzed for quality and accuracy. Successful application of local earthquake interferometry will produce a crustal image with identifiable sedimentary and basement reflectors and possibly a Moho reflection. Economically, local earthquake interferometry could lower the time and resource cost of active and passive seismic surveys while improving subsurface image quality in urban settings or areas of limited access. The applications of this method can potentially be expanded with the inclusion of seismic events with a magnitude of 1.0 or lower.
Temporal change in shallow subsurface P- and S-wave velocities and S-wave anisotropy inferred from coda wave interferometry

NASA Astrophysics Data System (ADS)

Yamamoto, M.; Nishida, K.; Takeda, T.

2012-12-01

Recent progresses in theoretical and observational researches on seismic interferometry reveal the possibility to detect subtle change in subsurface seismic structure. This high sensitivity of seismic interferometry to the medium properties may thus one of the most important ways to directly observe the time-lapse behavior of shallow crustal structure. Here, using the coda wave interferometry, we show the co-seismic and post-seismic changes in P- and S-wave velocities and S-wave anisotropy associated with the 2011 off the Pacific coast of Tohoku earthquake (M9.0). In this study, we use the acceleration data recorded at KiK-net stations operated by NIED, Japan. Each KiK-net station has a borehole whose typical depth is about 100m, and two three-component accelerometers are installed at the top and bottom of the borehole. To estimate the shallow subsurface P- and S-wave velocities and S-wave anisotropy between two sensors and their temporal change, we select about 1000 earthquakes that occurred between 2004 and 2012, and extract body waves propagating between borehole sensors by computing the cross-correlation functions (CCFs) of 3 x 3 component pairs. We use frequency bands of 2-4, 4-8, 8-16 Hz in our analysis. Each averaged CCF shows clear wave packets traveling between borehole sensors, and their travel times are almost consistent with those of P- and S-waves calculated from the borehole log data. Until the occurrence of the 2011 Tohoku earthquake, the estimated travel time at each station is rather stable with time except for weak seasonal/annual variation. On the other hand, the 2011 Tohoku earthquake and its aftershocks cause sudden decrease in the S-wave velocity at most of the KiK-net stations in eastern Japan. The typical value of S-wave velocity changes, which are measured by the time-stretching method, is about 5-15%. After this co-seismic change, the S-wave velocity gradually recovers with time, and the recovery continues for over one year following the logarithm of the lapse time. At some stations, the estimated P-wave velocity also shows co-seismic velocity decrease and subsequent gradual recovery. However, the magnitude of estimated P-wave velocity change is much smaller than that of S-wave, and at the other stations, the magnitude of P-wave velocity change is smaller than the resolution of our analysis. Using the CCFs computed from horizontal components, we also determine the seismic anisotropy in subsurface structure, and examine its temporal change. The estimated strength of anisotropy strength shows co-seismic increase at most of stations where co-seismic velocity change is detected. Nevertheless, the direction of anisotropy after the 2011 Tohoku earthquake stays about the same as before. These results suggest that, in addition to the change in pore pressure and corresponding decrease in the rigidity, the change in the aspect ratio of pre-existing subsurface fractures/micro-crack may be another key mechanism causing the co-seismic velocity change in shallow subsurface structures.
Nuclear emulsions for the detection of micrometric-scale fringe patterns: an application to positron interferometry

NASA Astrophysics Data System (ADS)

Aghion, S.; Ariga, A.; Bollani, M.; Ereditato, A.; Ferragut, R.; Giammarchi, M.; Lodari, M.; Pistillo, C.; Sala, S.; Scampoli, P.; Vladymyrov, M.

2018-05-01

Nuclear emulsions are capable of very high position resolution in the detection of ionizing particles. This feature can be exploited to directly resolve the micrometric-scale fringe pattern produced by a matter-wave interferometer for low energy positrons (in the 10–20 keV range). We have tested the performance of emulsion films in this specific scenario. Exploiting silicon nitride diffraction gratings as absorption masks, we produced periodic patterns with features comparable to the expected interferometer signal. Test samples with periodicities of 6, 7 and 20 μ m were exposed to the positron beam, and the patterns clearly reconstructed. Our results support the feasibility of matter-wave interferometry experiments with positrons.
Fringe localization requirements for three-dimensional flow visualization of shock waves in diffuse-illumination double-pulse holographic interferometry

NASA Technical Reports Server (NTRS)

Decker, A. J.

1982-01-01

A theory of fringe localization in rapid-double-exposure, diffuse-illumination holographic interferometry was developed. The theory was then applied to compare holographic measurements with laser anemometer measurements of shock locations in a transonic axial-flow compressor rotor. The computed fringe localization error was found to agree well with the measured localization error. It is shown how the view orientation and the curvature and positional variation of the strength of a shock wave are used to determine the localization error and to minimize it. In particular, it is suggested that the view direction not deviate from tangency at the shock surface by more than 30 degrees.
A scheme for recording a fast process at nanosecond scale by using digital holographic interferometry with continuous wave laser

NASA Astrophysics Data System (ADS)

Wang, Jun; Zhao, Jianlin; Di, Jianglei; Jiang, Biqiang

2015-04-01

A scheme for recording fast process at nanosecond scale by using digital holographic interferometry with continuous wave (CW) laser is described and demonstrated experimentally, which employs delayed-time fibers and angular multiplexing technique and can realize the variable temporal resolution at nanosecond scale and different measured depths of object field at certain temporal resolution. The actual delay-time is controlled by two delayed-time fibers with different lengths. The object field information in two different states can be simultaneously recorded in a composite hologram. This scheme is also suitable for recording fast process at picosecond scale, by using an electro-optic modulator.
Measurement of fluid properties using rapid-double-exposure and time-average holographic interferometry

NASA Technical Reports Server (NTRS)

Decker, A. J.

1984-01-01

The holographic recording of the time history of a flow feature in three dimensions is discussed. The use of diffuse illumination holographic interferometry or the three-dimensional visualization of flow features such as shock waves and turbulent eddies is described. The double-exposure and time-average methods are compared using the characteristic function and the results from a flow simulator. A time history requires a large hologram recording rate. Results of holographic cinematography of the shock waves in a flutter cascade are presented as an example. Future directions of this effort, including the availability and development of suitable lasers, are discussed. Previously announced in STAR as N84-21849
Advanced radiometric and interferometric milimeter-wave scene simulations

NASA Technical Reports Server (NTRS)

Hauss, B. I.; Moffa, P. J.; Steele, W. G.; Agravante, H.; Davidheiser, R.; Samec, T.; Young, S. K.

1993-01-01

Smart munitions and weapons utilize various imaging sensors (including passive IR, active and passive millimeter-wave, and visible wavebands) to detect/identify targets at short standoff ranges and in varied terrain backgrounds. In order to design and evaluate these sensors under a variety of conditions, a high-fidelity scene simulation capability is necessary. Such a capability for passive millimeter-wave scene simulation exists at TRW. TRW's Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code is a rigorous, benchmarked, end-to-end passive millimeter-wave scene simulation code for interpreting millimeter-wave data, establishing scene signatures and evaluating sensor performance. In passive millimeter-wave imaging, resolution is limited due to wavelength and aperture size. Where high resolution is required, the utility of passive millimeter-wave imaging is confined to short ranges. Recent developments in interferometry have made possible high resolution applications on military platforms. Interferometry or synthetic aperture radiometry allows the creation of a high resolution image with a sparsely filled aperture. Borrowing from research work in radio astronomy, we have developed and tested at TRW scene reconstruction algorithms that allow the recovery of the scene from a relatively small number of spatial frequency components. In this paper, the TRW modeling capability is described and numerical results are presented.
Controlled-source seismic interferometry with one way wave fields

NASA Astrophysics Data System (ADS)

van der Neut, J.; Wapenaar, K.; Thorbecke, J. W.

2008-12-01

In Seismic Interferometry we generally cross-correlate registrations at two receiver locations and sum over an array of sources to retrieve a Green's function as if one of the receiver locations hosts a (virtual) source and the other receiver location hosts an actual receiver. One application of this concept is to redatum an area of surface sources to a downhole receiver location, without requiring information about the medium between the sources and receivers, thus providing an effective tool for imaging below complex overburden, which is also known as the Virtual Source method. We demonstrate how elastic wavefield decomposition can be effectively combined with controlled-source Seismic Interferometry to generate virtual sources in a downhole receiver array that radiate only down- or upgoing P- or S-waves with receivers sensing only down- or upgoing P- or S- waves. For this purpose we derive exact Green's matrix representations from a reciprocity theorem for decomposed wavefields. Required is the deployment of multi-component sources at the surface and multi- component receivers in a horizontal borehole. The theory is supported with a synthetic elastic model, where redatumed traces are compared with those of a directly modeled reflection response, generated by placing active sources at the virtual source locations and applying elastic wavefield decomposition on both source and receiver side.

Numerical modeling of nonlinear modulation of coda wave interferometry in a multiple scattering medium with the presence of a localized micro-cracked zone

NASA Astrophysics Data System (ADS)

Chen, Guangzhi; Pageot, Damien; Legland, Jean-Baptiste; Abraham, Odile; Chekroun, Mathieu; Tournat, Vincent

2018-04-01

The spectral element method is used to perform a parametric sensitivity study of the nonlinear coda wave interferometry (NCWI) method in a homogeneous sample with localized damage [1]. The influence of a strong pump wave on a localized nonlinear damage zone is modeled as modifications to the elastic properties of an effective damage zone (EDZ), depending on the pump wave amplitude. The local change of the elastic modulus and the attenuation coefficient have been shown to vary linearly with respect to the excitation amplitude of the pump wave as in previous experimental studies of Zhang et al. [2]. In this study, the boundary conditions of the cracks, i.e. clapping effects is taken into account in the modeling of the damaged zone. The EDZ is then modeled with random cracks of random orientations, new parametric studies are established to model the pump wave influence with two new parameters: the change of the crack length and the crack density. The numerical results reported constitute another step towards quantification and forecasting of the nonlinear acoustic response of a cracked material, which proves to be necessary for quantitative non-destructive evaluation.
Habituation of the cold shock response is inhibited by repeated anxiety: Implications for safety behaviour on accidental cold water immersions.

PubMed

Barwood, Martin J; Corbett, Jo; Tipton, Mike; Wagstaff, Christopher; Massey, Heather

2017-05-15

Accidental cold-water immersion (CWI) triggers the life-threatening cold shock response (CSR) which is a precursor to sudden death on immersion. One practical means of reducing the CSR is to induce an habituation by undergoing repeated short CWIs. Habituation of the CSR is known to be partially reversed by the concomitant experience of acute anxiety, raising the possibility that repeated anxiety could prevent CSR habituation; we tested this hypothesis. Sixteen participants (12 male, 4 female) completed seven, seven-minute immersions in to cold water (15°C). Immersion one acted as a control (CON1). During immersions two to five, which would ordinarily induce an habituation, anxiety levels were repeatedly increased (CWI-ANX rep ) by deception and a demanding mathematical task. Immersions six and seven were counter-balanced with another high anxiety condition (CWI-ANX rep ) or a further control (CON2). Anxiety (20cm visual analogue scale) and cardiorespiratory responses (cardiac frequency [f c ], respiratory frequency [f R ], tidal volume [V T ], minute ventilation [V̇ E ]) were measured. Comparisons were made between experimental immersions (CON1, final CWI-ANX rep , CON2), across habituation immersions and with data from a previous study. Anxiety levels were sustained at a similar level throughout the experimental and habituation immersions (mean [SD] CON1: 7.0 [4.0] cm; CON2: 5.8 [5.2] cm cf CWI-ANX rep : 7.3 [5.5] cm; p>0.05). This culminated in failure of the CSR to habituate even when anxiety levels were not manipulated (i.e. CON2). These data were different (p<0.05) to previous studies where anxiety levels were allowed to fall across habituation immersions and the CSR consequently habituated. Repeated anxiety prevented CSR habituation. A protective strategy that includes inducing habituation for those at risk should include techniques to lower anxiety associated with the immersion event or habituation may not be beneficial in the emergency scenario. Copyright © 2017 Elsevier Inc. All rights reserved.
Detecting inertial effects with airborne matter-wave interferometry

PubMed Central

Geiger, R.; Ménoret, V.; Stern, G.; Zahzam, N.; Cheinet, P.; Battelier, B.; Villing, A.; Moron, F.; Lours, M.; Bidel, Y.; Bresson, A.; Landragin, A.; Bouyer, P.

2011-01-01

Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / √Hz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves. PMID:21934658
Applying the seismic interferometry method to vertical seismic profile data using tunnel excavation noise as source

NASA Astrophysics Data System (ADS)

Jurado, Maria Jose; Teixido, Teresa; Martin, Elena; Segarra, Miguel; Segura, Carlos

2013-04-01

In the frame of the research conducted to develop efficient strategies for investigation of rock properties and fluids ahead of tunnel excavations the seismic interferometry method was applied to analyze the data acquired in boreholes instrumented with geophone strings. The results obtained confirmed that seismic interferometry provided an improved resolution of petrophysical properties to identify heterogeneities and geological structures ahead of the excavation. These features are beyond the resolution of other conventional geophysical methods but can be the cause severe problems in the excavation of tunnels. Geophone strings were used to record different types of seismic noise generated at the tunnel head during excavation with a tunnelling machine and also during the placement of the rings covering the tunnel excavation. In this study we show how tunnel construction activities have been characterized as source of seismic signal and used in our research as the seismic source signal for generating a 3D reflection seismic survey. The data was recorded in vertical water filled borehole with a borehole seismic string at a distance of 60 m from the tunnel trace. A reference pilot signal was obtained from seismograms acquired close the tunnel face excavation in order to obtain best signal-to-noise ratio to be used in the interferometry processing (Poletto et al., 2010). The seismic interferometry method (Claerbout 1968) was successfully applied to image the subsurface geological structure using the seismic wave field generated by tunneling (tunnelling machine and construction activities) recorded with geophone strings. This technique was applied simulating virtual shot records related to the number of receivers in the borehole with the seismic transmitted events, and processing the data as a reflection seismic survey. The pseudo reflective wave field was obtained by cross-correlation of the transmitted wave data. We applied the relationship between the transmission response and the reflection response for a 1D multilayer structure, and next 3D approach (Wapenaar 2004). As a result of this seismic interferometry experiment the 3D reflectivity model (frequencies and resolution ranges) was obtained. We proved also that the seismic interferometry approach can be applied in asynchronous seismic auscultation. The reflections detected in the virtual seismic sections are in agreement with the geological features encountered during the excavation of the tunnel and also with the petrophysical properties and parameters measured in previous geophysical borehole logging. References Claerbout J.F., 1968. Synthesis of a layered medium from its acoustic transmision response. Geophysics, 33, 264-269 Flavio Poletto, Piero Corubolo and Paolo Comeli.2010. Drill-bit seismic interferometry whith and whitout pilot signals. Geophysical Prospecting, 2010, 58, 257-265. Wapenaar, K., J. Thorbecke, and D. Draganov, 2004, Relations between reflection and transmission responses of three-dimensional inhomogeneous media: Geophysical Journal International, 156, 179-194.
Heat shock proteins MoSsb1, MoSsz1, and MoZuo1 attenuate MoMkk1-mediated CWI signaling and are important for growth and pathogenicity of Magnaporthe oryzae.

PubMed

Yang, Jie; Liu, Muxing; Liu, Xinyu; Yin, Ziyi; Sun, Yi; Zhang, Haifeng; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

2018-06-05

The mitogen-activated protein (MAP) kinase MoMkk1 governs the cell wall integrity (CWI) pathway in the rice blast fungus Magnaporthe oryzae. To understand the underlying mechanism, we have identified MoSsb1 as one of the MoMkk1-interacting proteins. MoSsb1 is a stress-seventy subfamily B (Ssb) protein homolog, sharing high amino acid sequence homology with the 70-kDa heat shock proteins (Hsp70s). Hsp70 proteins are a family of conserved and ubiquitously expressed chaperones that regulate protein biogenesis by promoting protein folding, preventing protein aggregation and controlling protein degradation. We found that MoSsb1 regulates the synthesis of nascent polypeptide chains and this regulation is achieved by being in complex with other members of heat shock proteins: Hsp70 MoSsz1 and 40-kDa heat shock protein (Hsp40) MoZuo1. MoSsb1 is important for the growth, conidiation and full virulence of the blast fungus and this role is also shared by MoSsz1 and MoZuo1. Importantly, MoSsb1, MoSsz1 and MoZuo1 are all involved in the regulation of the CWI MAP kinase pathway by modulating MoMkk1 biosynthesis. Our studies reveal novel insights into how MoSsb1, MoSsz1 and MoZuo1 affect CWI signaling that is involved in regulating growth, differentiation and virulence of M. oryzae and highlight the conserved functional mechanisms of Hsp proteins in pathogenic fungi.
Does Pre-Cooling With Whole-Body Immersion Affect Thermal Sensation or Perceived Exertion?: A Critically-Appraised Topic.

PubMed

Wohlfert, Timothy M; Miller, Kevin C

2018-02-21

Clinical Scenario: Exertional heat stroke (EHS) is a potentially deadly heat illness and poses a significant health risk to athletes; EHS survival rates are near 100% if properly recognized and treated. 1 Whole body cold water immersion (CWI) is the most effective method of lowering body core temperature. 2 Precooling (PC) with CWI before exercise may prevent severe hyperthermia and/or EHS by increasing the body's overall heat-storage capacity. 3 However, PC may also alter athletes' perception of how hot they feel or how hard they are exercising. Consequently, they may be unable to accurately perceive their body core temperature or how hard they are working which may predispose them to severe hyperthermia or EHS. Does PC with whole-body CWI affect thermal sensation (TS) or rating of perceived exertion (RPE) during exercise in the heat? In four studies, 4-7 RPE during exercise ranged from 12 ± 2 to 20 ± 3 with no clinically meaningful differences between PC and control trials. Thermal sensation scores ranged from 2 ± 1 to 8 ± 0.5 in control trials and from 2 ± 1 to 7.5 ± 0.5 during PC trials. Clinical Bottom Line: Precooling did not cause clinically-meaningful differences in RPE or TS during exercise. It is unlikely PC would predispose athletes to EHS by altering perceptions of exercise intensity or body core temperature. Strength of Recommendation: None of the reviewed studies 4-7 (all level 2 studies with PEDro scores ≥5) suggest PC with CWI influences RPE or TS in exercising males.
Brain mapping after prolonged cycling and during recovery in the heat.

PubMed

De Pauw, Kevin; Roelands, Bart; Marusic, Uros; Tellez, Helio Fernandez; Knaepen, Kristel; Meeusen, Romain

2013-11-01

The aim of this study was to determine the effect of prolonged intensive cycling and postexercise recovery in the heat on brain sources of altered brain oscillations. After a max test and familiarization trial, nine trained male subjects (23 ± 3 yr; maximal oxygen uptake = 62.1 ± 5.3 ml·min(-1)·kg(-1)) performed three experimental trials in the heat (30°C; relative humidity 43.7 ± 5.6%). Each trial consisted of two exercise tasks separated by 1 h. The first was a 60-min constant-load trial, followed by a 30-min simulated time trial (TT1). The second comprised a 12-min simulated time trial (TT2). After TT1, active recovery (AR), passive rest (PR), or cold water immersion (CWI) was applied for 15 min. Electroencephalography was measured at baseline and during postexercise recovery. Standardized low-resolution brain electromagnetic tomography was applied to accurately pinpoint and localize altered electrical neuronal activity. After CWI, PR and AR subjects completed TT2 in 761 ± 42, 791 ± 76, and 794 ± 62 s, respectively. A prolonged intensive cycling performance in the heat decreased β activity across the whole brain. Postexercise AR and PR elicited no significant electrocortical differences, whereas CWI induced significantly increased β3 activity in Brodmann areas (BA) 13 (posterior margin of insular cortex) and BA 40 (supramarginal gyrus). Self-paced prolonged exercise in the heat seems to decrease β activity, hence representing decreased arousal. Postexercise CWI increased β3 activity at BA 13 and 40, brain areas involved in somatosensory information processing.
Time-Delay Interferometry for Space-based Gravitational Wave Searches

NASA Technical Reports Server (NTRS)

Armstrong, J.; Estabrook, F.; Tinto, M.

1999-01-01

Ground-based, equal-arm-length laser interferometers are being built to measure high-frequency astrophysical graviatational waves. Because of the arm-length equality, laser light experiences the same delay in each arm and thus phase or frequency noise from the laser itself precisely cancels at the photodetector.
Atom Interferometry

ScienceCinema

Kasevich, Mark

2017-12-22

Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newtonâs constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?
Atom Interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasevich, Mark

2008-05-07

Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Canmore » atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?« less
Physical characteristics cannot be used to predict cooling time using cold-water immersion as a treatment for exertional hyperthermia.

PubMed

Poirier, Martin P; Notley, Sean R; Flouris, Andreas D; Kenny, Glen P

2018-03-12

We examined if physical characteristics could be used to predict cooling time during cold water immersion (CWI, 2°C) following exertional hyperthermia (rectal temperature ≥39.5°C) in a physically heterogeneous group of men and women (n=62). Lean body mass was the only significant predictor of cooling time following CWI (R²=0.137; P<0.001); however that prediction did not provide the precision (mean residual square error: 3.18±2.28 min) required to act as a safe alternative to rectal temperature measurements.
Comparison of body cooling methods on physiological and perceptual measures of mildly hyperthermic athletes.

PubMed

DeMartini, Julie K; Ranalli, Gregory F; Casa, Douglas J; Lopez, Rebecca M; Ganio, Matthew S; Stearns, Rebecca L; McDermott, Brendon P; Armstrong, Lawrence E; Maresh, Carl M

2011-08-01

Hyperthermia is common among athletes and in a variety of environments. The purpose of this study was to evaluate the effectiveness of cooling methods on core body temperature, heart rate (HR), and perceptual readings in individuals after exercise. Sixteen subjects (age: 24 ± 6 years, height: 182 ± 7 cm, weight: 74.03 ± 9.17 kg, and body fat: 17.08 ± 6.23%) completed 10 exercise sessions in warm conditions (WBGT: 26.64 ± 4.71°C) followed by body cooling by 10 different methods. Cooling methods included cold water immersion (CWI), shade, Port-a-Cool® (FAN), Emergency Cold Containment System® (ECCS), Rehab. Hood® (HOOD), Game Ready Active Cooling Vest™ (GRV), Nike Ice Vest™ (NIV), ice buckets (IBs), and ice towels (IT). These cooling modes were compared with a control (SUN). Rectal temperature (T(re)), HR, thermal sensation, thirst sensation, and a 56-question Environmental Symptoms Questionnaire (ESQ) were used to assess physiological and perceptual data. Average T(re) after exercise across all trials was 38.73 ± 0.12°C. After 10 minutes of cooling, CWI (-0.65 ± 0.29°C), ECCS (-0.68 ± 0.24°C), and IB (-0.74 ± 0.34°C) had significantly (p < 0.006) greater decreases in T(re) compared with that in SUN (-0.42 ± 0.15°C). The HR after 10 minutes of cooling was significantly (p < 0.006) lower for CWI (82 ± 15 b·min(-1)), ECCS (87 ± 14 b·min(-1)), and IT (84 ± 15 b·min(-1)) when compared with SUN (101 ± 15 b·min(-1)). The thermal sensation between modalities was all significantly (p < 0.006) lower (CWI: 1.5 ± 0.5; Fan: 3.0 ± 1.0; ECCS: 4.5 ± 1.0; Hood: 4.5 ± 0.5; GRV: 4.0 ± 0.5; NIV: 4.5 ± 1.0; IB: 4.0 ± 1.0; IT: 3.0 ± 1.0) when compared with SUN (5.5 ± 0.5), except for Shade (5.0 ± 1.0). There were no significant differences (p > 0.006) in thirst sensation between modalities. The ESQ scores were significantly (p < 0.006) lower for CWI (1 ± 6), Fan (4 ± 5), and IT (3 ± 8) compared with that for SUN (13 ± 12). In conclusion, when athletes experience mild hyperthermia, CWI, ECCS, and IB resulted in a significantly greater decrease in T(re). These cooling strategies are recommended to decrease T(re) during a brief recovery period between exercise bouts.
Water immersion recovery for athletes: effect on exercise performance and practical recommendations.

PubMed

Versey, Nathan G; Halson, Shona L; Dawson, Brian T

2013-11-01

Water immersion is increasingly being used by elite athletes seeking to minimize fatigue and accelerate post-exercise recovery. Accelerated short-term (hours to days) recovery may improve competition performance, allow greater training loads or enhance the effect of a given training load. However, the optimal water immersion protocols to assist short-term recovery of performance still remain unclear. This article will review the water immersion recovery protocols investigated in the literature, their effects on performance recovery, briefly outline the potential mechanisms involved and provide practical recommendations for their use by athletes. For the purposes of this review, water immersion has been divided into four techniques according to water temperature: cold water immersion (CWI; ≤20 °C), hot water immersion (HWI; ≥36 °C), contrast water therapy (CWT; alternating CWI and HWI) and thermoneutral water immersion (TWI; >20 to <36 °C). Numerous articles have reported that CWI can enhance recovery of performance in a variety of sports, with immersion in 10-15 °C water for 5-15 min duration appearing to be most effective at accelerating performance recovery. However, the optimal CWI duration may depend on the water temperature, and the time between CWI and the subsequent exercise bout appears to influence the effect on performance. The few studies examining the effect of post-exercise HWI on subsequent performance have reported conflicting findings; therefore the effect of HWI on performance recovery is unclear. CWT is most likely to enhance performance recovery when equal time is spent in hot and cold water, individual immersion durations are short (~1 min) and the total immersion duration is up to approximately 15 min. A dose-response relationship between CWT duration and recovery of exercise performance is unlikely to exist. Some articles that have reported CWT to not enhance performance recovery have had methodological issues, such as failing to detect a decrease in performance in control trials, not performing full-body immersion, or using hot showers instead of pools. TWI has been investigated as both a control to determine the effect of water temperature on performance recovery, and as an intervention itself. However, due to conflicting findings it is uncertain whether TWI improves recovery of subsequent exercise performance. Both CWI and CWT appear likely to assist recovery of exercise performance more than HWI and TWI; however, it is unclear which technique is most effective. While the literature on the use of water immersion for recovery of exercise performance is increasing, further research is required to obtain a more complete understanding of the effects on performance.
Evaluation of diffuse-illumination holographic cinematography in a flutter cascade

NASA Technical Reports Server (NTRS)

Decker, A. J.

1986-01-01

Since 1979, the Lewis Research Center has examined holographic cinematography for three-dimensional flow visualization. The Nd:YAG lasers used were Q-switched, double-pulsed, and frequency-doubled, operating at 20 pulses per second. The primary subjects for flow visualization were the shock waves produced in two flutter cascades. Flow visualization was by diffuse-illumination, double-exposure, and holographic interferometry. The performances of the lasers, holography, and diffuse-illumination interferometry are evaluated in single-window wind tunnels. The fringe-contrast factor is used to evaluate the results. The effects of turbulence on shock-wave visualization in a transonic flow are discussed. The depth of field for visualization of a turbulent structure is demonstrated to be a measure of the relative density and scale of that structure. Other items discussed are the holographic emulsion, tests of coherence and polarization, effects of windows and diffusers, hologram bleaching, laser configurations, influence and handling of specular reflections, modes of fringe localization, noise sources, and coherence requirements as a function of the pulse energy. Holography and diffuse illumination interferometry are also reviewed.
Absolute marine gravimetry with matter-wave interferometry.

PubMed

Bidel, Y; Zahzam, N; Blanchard, C; Bonnin, A; Cadoret, M; Bresson, A; Rouxel, D; Lequentrec-Lalancette, M F

2018-02-12

Measuring gravity from an aircraft or a ship is essential in geodesy, geophysics, mineral and hydrocarbon exploration, and navigation. Today, only relative sensors are available for onboard gravimetry. This is a major drawback because of the calibration and drift estimation procedures which lead to important operational constraints. Atom interferometry is a promising technology to obtain onboard absolute gravimeter. But, despite high performances obtained in static condition, no precise measurements were reported in dynamic. Here, we present absolute gravity measurements from a ship with a sensor based on atom interferometry. Despite rough sea conditions, we obtained precision below 10 -5 m s -2 . The atom gravimeter was also compared with a commercial spring gravimeter and showed better performances. This demonstration opens the way to the next generation of inertial sensors (accelerometer, gyroscope) based on atom interferometry which should provide high-precision absolute measurements from a moving platform.
Experimental validation of ultrasonic guided modes in electrical cables by optical interferometry.

PubMed

Mateo, Carlos; de Espinosa, Francisco Montero; Gómez-Ullate, Yago; Talavera, Juan A

2008-03-01

In this work, the dispersion curves of elastic waves propagating in electrical cables and in bare copper wires are obtained theoretically and validated experimentally. The theoretical model, based on Gazis equations formulated according to the global matrix methodology, is resolved numerically. Viscoelasticity and attenuation are modeled theoretically using the Kelvin-Voigt model. Experimental tests are carried out using interferometry. There is good agreement between the simulations and the experiments despite the peculiarities of electrical cables.
Flow visualization of acoustic levitation experiment

NASA Technical Reports Server (NTRS)

Baroth, ED

1987-01-01

Acoustic levitation experiments for space applications were performed. Holographic interferometry is being used to study the heat transfer rates on a heated rod enclosed in a 6 cu in chamber. Acoustic waves at levels up to 150 db increased the heating rates to the rod by factors of three to four. High speed real time holographic interferometry was used to measure the boundary layer on the heated rod. Data reduction and digitization of the interferograms are being implemented.
Community-wide intervention and population-level physical activity: a 5-year cluster randomized trial.

PubMed

Kamada, Masamitsu; Kitayuguchi, Jun; Abe, Takafumi; Taguri, Masataka; Inoue, Shigeru; Ishikawa, Yoshiki; Bauman, Adrian; Lee, I-Min; Miyachi, Motohiko; Kawachi, Ichiro

2018-04-01

Evidence from a limited number of short-term trials indicates the difficulty in achieving population-level improvements in physical activity (PA) through community-wide interventions (CWIs). We sought to evaluate the effectiveness of a 5-year CWI for promoting PA in middle-aged and older adults using a cluster randomized design. We randomized 12 communities in Unnan, Japan, to either intervention (9) or control (3). Additionally, intervention communities were randomly allocated to three subgroups by different PA types promoted. Randomly sampled residents aged 40-79 years responded to the baseline survey (n = 4414; 74%) and were followed at 1, 3 and 5 years (78-83% response rate). The intervention was a 5-year CWI using social marketing to promote PA. The primary outcome was a change in recommended levels of PA. Compared with control communities, adults achieving recommended levels of PA increased in intervention communities [adjusted change difference = 4.6 percentage points (95% confidence interval: 0.4, 8.8)]. The intervention was effective for promoting all types of recommended PAs, i.e. aerobic (walking, 6.4%), flexibility (6.1%) and muscle-strengthening activities (5.7%). However, a bundled approach, which attempted to promote all forms of PAs above simultaneously, was not effective (1.3-3.4%, P ≥ 0.138). Linear dose-response relationships between the CWI awareness and changes in PA were observed (P ≤ 0.02). Pain intensity decreased in shoulder (intervention and control) and lower back (intervention only) but there was little change difference in all musculoskeletal pain outcomes between the groups. The 5-year CWI using the focused social marketing strategy increased the population-level of PA.
Plant cell wall-mediated immunity: cell wall changes trigger disease resistance responses.

PubMed

Bacete, Laura; Mélida, Hugo; Miedes, Eva; Molina, Antonio

2018-02-01

Plants have evolved a repertoire of monitoring systems to sense plant morphogenesis and to face environmental changes and threats caused by different attackers. These systems integrate different signals into overreaching triggering pathways which coordinate developmental and defence-associated responses. The plant cell wall, a dynamic and complex structure surrounding every plant cell, has emerged recently as an essential component of plant monitoring systems, thus expanding its function as a passive defensive barrier. Plants have a dedicated mechanism for maintaining cell wall integrity (CWI) which comprises a diverse set of plasma membrane-resident sensors and pattern recognition receptors (PRRs). The PRRs perceive plant-derived ligands, such as peptides or wall glycans, known as damage-associated molecular patterns (DAMPs). These DAMPs function as 'danger' alert signals activating DAMP-triggered immunity (DTI), which shares signalling components and responses with the immune pathways triggered by non-self microbe-associated molecular patterns that mediate disease resistance. Alteration of CWI by impairment of the expression or activity of proteins involved in cell wall biosynthesis and/or remodelling, as occurs in some plant cell wall mutants, or by wall damage due to colonization by pathogens/pests, activates specific defensive and growth responses. Our current understanding of how these alterations of CWI are perceived by the wall monitoring systems is scarce and few plant sensors/PRRs and DAMPs have been characterized. The identification of these CWI sensors and PRR-DAMP pairs will help us to understand the immune functions of the wall monitoring system, and might allow the breeding of crop varieties and the design of agricultural strategies that would enhance crop disease resistance. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.
Effect of cold or thermoneutral water immersion on post-exercise heart rate recovery and heart rate variability indices.

PubMed

Al Haddad, Hani; Laursen, Paul B; Chollet, Didier; Lemaitre, Frédéric; Ahmaidi, Saïd; Buchheit, Martin

2010-08-25

This study aimed to investigate the effect of cold and thermoneutral water immersion on post-exercise parasympathetic reactivation, inferred from heart rate (HR) recovery (HRR) and HR variability (HRV) indices. Twelve men performed, on three separate occasions, an intermittent exercise bout (all-out 30-s Wingate test, 5 min seated recovery, followed by 5 min of submaximal running exercise), randomly followed by 5 min of passive (seated) recovery under either cold (CWI), thermoneutral water immersion (TWI) or control (CON) conditions. HRR indices (e.g., heart beats recovered in the first minute after exercise cessation, HRR(60)(s)) and vagal-related HRV indices (i.e., natural logarithm of the square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals (Ln rMSSD)) were calculated for the three recovery conditions. HRR(60)(s) was faster in water immersion compared with CON conditions [30+/-9 beats min(-)(1) for CON vs. 43+/- 10 beats min(-)(1) for TWI (P=0.003) and 40+/-13 beats min(-)(1) for CWI (P=0.017)], while no difference was found between CWI and TWI (P=0.763). Ln rMSSD was higher in CWI (2.32+/-0.67 ms) compared with CON (1.98+/-0.74 ms, P=0.05) and TWI (2.01+/-0.61 ms, P=0.08; aES=1.07) conditions, with no difference between CON and TWI (P=0.964). Water immersion is a simple and efficient means of immediately triggering post-exercise parasympathetic activity, with colder immersion temperatures likely to be more effective at increasing parasympathetic activity. Copyright 2010 Elsevier B.V. All rights reserved.

Can Cold Water Immersion Enhance Recovery in Elite Olympic Weightlifters? An Individualized Perspective.

PubMed

Schimpchen, Jan; Wagner, Maximilian; Ferrauti, Alexander; Kellmann, Michael; Pfeiffer, Mark; Meyer, Tim

2017-06-01

We investigated whether cold water immersion (CWI) after intensive training sessions can enhance recovery in elite Olympic weightlifters, taking into account each athlete's individual response pattern. The entire German male Olympic weightlifting national team participated in the study (n = 7), ensuring collection of data from elite athletes only. Using a randomized cross-over design, the athletes went through 2 high-intensity training microcycles consisting of 5 training sessions that were either followed by a CWI or passive recovery. Barbell speed in a snatch pull movement, blood parameters, and subjective ratings of general fatigue and recovery were assessed throughout the study. Physical performance at 2 snatch pull intensities (85% one repetition maximum [1RM]: -0.15% vs. -0.22%, p = 0.94; 90% 1RM: -0.7% vs. +1.23%, p = 0.25) did not differ significantly (condition × time). Although questionnaires revealed a significant decline in the ratings of overall recovery (p < 0.001) and a significantly higher rating of overall stress (p = 0.03) over time, no significant differences between conditions (p = 0.14; p = 0.98) could be revealed. Similarly, neither of the analyzed blood parameters changed significantly between conditions over time (creatine kinase: p = 0.53; urea: p = 0.43; cortisol: p = 0.59; testosterone: p = 0.53; testosterone:cortisol ratio: p = 0.69). In general, CWI did not prove to be an effective tool to enhance recovery in elite Olympic weightlifters over a 3-day intensive training period. However, even though the group was rather homogeneous with regard to performance, there were considerable intersubject differences in their response to CWI. It seems that athletes are best advised on a case-by-case basis.
Serum levels of bupivacaine after pre-peritoneal bolus vs. epidural bolus injection for analgesia in abdominal surgery: A safety study within a randomized controlled trial.

PubMed

Mungroop, Timothy H; van Samkar, Ganapathy; Geerts, Bart F; van Dieren, Susan; Besselink, Marc G; Veelo, Denise P; Lirk, Philipp

2017-01-01

Continuous wound infiltration (CWI) has become increasingly popular in recent years as an alternative to epidural analgesia. As catheters are not placed until the end of surgery, more intraoperative opioid analgesics might be needed. We, therefore, added a single pre-peritoneal bolus of bupivacaine at the start of laparotomy, similar to the bolus given with epidural analgesia. This was a comparative study within a randomized controlled trial (NTR4948). Patients undergoing hepato-pancreato-biliary surgery received either a pre-peritoneal bolus of 30ml bupivacaine 0.25%, or an epidural bolus of 10ml bupivacaine 0.25% at the start of laparotomy. In a subgroup of patients, we sampled blood and determined bupivacaine serum levels 20, 40, 60 and 80 minutes after bolus injection. We assumed toxicity of bupivacaine to be >1000 ng/ml. A total of 20 patients participated in this sub-study. All plasma levels measured as well as the upper limit of the predicted 99% confidence intervals per time point were well below the toxicity limit. In a mixed linear-effect model both groups did not differ statistically significant (p = 0.131). The intra-operative use of opioids was higher with CWI as compared to epidural (86 (SD 73) μg sufentanil vs. 50 (SD 32). In this exploratory study, the pre-peritoneal bolus using bupivacaine resulted in serum bupivacaine concentrations well below the commonly accepted toxic threshold. With CWI more additional analgesics are needed intraoperatively as compared to epidural analgesia, although this is compensated by a reduction in use of vasopressors with CWI. Netherlands Trial Register NTR4948.
Serum levels of bupivacaine after pre-peritoneal bolus vs. epidural bolus injection for analgesia in abdominal surgery: A safety study within a randomized controlled trial

PubMed Central

Geerts, Bart F.; van Dieren, Susan; Besselink, Marc G.; Veelo, Denise P.; Lirk, Philipp

2017-01-01

Background Continuous wound infiltration (CWI) has become increasingly popular in recent years as an alternative to epidural analgesia. As catheters are not placed until the end of surgery, more intraoperative opioid analgesics might be needed. We, therefore, added a single pre-peritoneal bolus of bupivacaine at the start of laparotomy, similar to the bolus given with epidural analgesia. Methods This was a comparative study within a randomized controlled trial (NTR4948). Patients undergoing hepato-pancreato-biliary surgery received either a pre-peritoneal bolus of 30ml bupivacaine 0.25%, or an epidural bolus of 10ml bupivacaine 0.25% at the start of laparotomy. In a subgroup of patients, we sampled blood and determined bupivacaine serum levels 20, 40, 60 and 80 minutes after bolus injection. We assumed toxicity of bupivacaine to be >1000 ng/ml. Results A total of 20 patients participated in this sub-study. All plasma levels measured as well as the upper limit of the predicted 99% confidence intervals per time point were well below the toxicity limit. In a mixed linear-effect model both groups did not differ statistically significant (p = 0.131). The intra-operative use of opioids was higher with CWI as compared to epidural (86 (SD 73) μg sufentanil vs. 50 (SD 32). Conclusions In this exploratory study, the pre-peritoneal bolus using bupivacaine resulted in serum bupivacaine concentrations well below the commonly accepted toxic threshold. With CWI more additional analgesics are needed intraoperatively as compared to epidural analgesia, although this is compensated by a reduction in use of vasopressors with CWI. Trial registration Netherlands Trial Register NTR4948 PMID:28614364
Community-wide intervention and population-level physical activity: a 5-year cluster randomized trial

PubMed Central

Kamada, Masamitsu; Kitayuguchi, Jun; Abe, Takafumi; Taguri, Masataka; Inoue, Shigeru; Ishikawa, Yoshiki; Bauman, Adrian; Lee, I-Min; Miyachi, Motohiko; Kawachi, Ichiro

2018-01-01

Abstract Background Evidence from a limited number of short-term trials indicates the difficulty in achieving population-level improvements in physical activity (PA) through community-wide interventions (CWIs). We sought to evaluate the effectiveness of a 5-year CWI for promoting PA in middle-aged and older adults using a cluster randomized design. Methods We randomized 12 communities in Unnan, Japan, to either intervention (9) or control (3). Additionally, intervention communities were randomly allocated to three subgroups by different PA types promoted. Randomly sampled residents aged 40–79 years responded to the baseline survey (n = 4414; 74%) and were followed at 1, 3 and 5 years (78–83% response rate). The intervention was a 5-year CWI using social marketing to promote PA. The primary outcome was a change in recommended levels of PA. Results Compared with control communities, adults achieving recommended levels of PA increased in intervention communities [adjusted change difference = 4.6 percentage points (95% confidence interval: 0.4, 8.8)]. The intervention was effective for promoting all types of recommended PAs, i.e. aerobic (walking, 6.4%), flexibility (6.1%) and muscle-strengthening activities (5.7%). However, a bundled approach, which attempted to promote all forms of PAs above simultaneously, was not effective (1.3–3.4%, P ≥ 0.138). Linear dose–response relationships between the CWI awareness and changes in PA were observed (P ≤ 0.02). Pain intensity decreased in shoulder (intervention and control) and lower back (intervention only) but there was little change difference in all musculoskeletal pain outcomes between the groups. Conclusions The 5-year CWI using the focused social marketing strategy increased the population-level of PA. PMID:29228255
Can Temperate-Water Immersion Effectively Reduce Rectal Temperature in Exertional Heat Stroke? A Critically Appraised Topic.

PubMed

Truxton, Tyler T; Miller, Kevin C

2017-09-01

Clinical Scenario: Exertional heat stroke (EHS) is a medical emergency which, if left untreated, can result in death. The standard of care for EHS patients includes confirmation of hyperthermia via rectal temperature (T rec ) and then immediate cold-water immersion (CWI). While CWI is the fastest way to reduce T rec , it may be difficult to lower and maintain water bath temperature in the recommended ranges (1.7°C-15°C [35°F-59°F]) because of limited access to ice and/or the bath being exposed to high ambient temperatures for long periods of time. Determining if T rec cooling rates are acceptable (ie, >0.08°C/min) when significantly hyperthermic humans are immersed in temperate water (ie, ≥20°C [68°F]) has applications for how EHS patients are treated in the field. Are T rec cooling rates acceptable (≥0.08°C/min) when significantly hyperthermic humans are immersed in temperate water? T rec cooling rates of hyperthermic humans immersed in temperate water (≥20°C [68°F]) ranged from 0.06°C/min to 0.19°C/min. The average T rec cooling rate for all examined studies was 0.11±0.06°C/min. Clinical Bottom Line: Temperature water immersion (TWI) provides acceptable (ie, >0.08°C/min) T rec cooling rates for hyperthermic humans post-exercise. However, CWI cooling rates are higher and should be used if feasible (eg, access to ice, shaded treatment areas). Strength of Recommendation: The majority of evidence (eg, Level 2 studies with PEDro scores ≥5) suggests TWI provides acceptable, though not ideal, T rec cooling. If possible, CWI should be used instead of TWI in EHS scenarios.
Analysis of localized fringes in the holographic optical Schlieren system

NASA Technical Reports Server (NTRS)

Kurtz, R. L.

1980-01-01

The relation between localization of interference fringes in classical and holographic interferometry is reviewed and an application of holographic interferometry is considered for which the object is a transparent medium with nonhomogeneous refractive index. The technique is based on the analysis of the optical path length change of the object wave as it propagates through a transparent medium. Phase shifts due to variations of the speed of light within the medium give rise to an interference pattern. The resulting interferogram can be used to determine the physical properties of the medium or transparent object. Such properties include the mass density of fluids, electron densities of plasmas, the temperature of fluids, the chemical species concentration of fluids, and the state of stress in solids. The optical wave used can be either a simple plane or spherical wave, or it may be a complicated spatial wave scattered by a diffusing screen. The mathematical theory on the formation and analysis of localized fringes, the general theoretical concepts used, and a computer code for analysis are included along with the inversion of fringe order data.
Search for light scalar dark matter with atomic gravitational wave detectors

NASA Astrophysics Data System (ADS)

Arvanitaki, Asimina; Graham, Peter W.; Hogan, Jason M.; Rajendran, Surjeet; Van Tilburg, Ken

2018-04-01

We show that gravitational wave detectors based on a type of atom interferometry are sensitive to ultralight scalar dark matter. Such dark matter can cause temporal oscillations in fundamental constants with a frequency set by the dark matter mass and amplitude determined by the local dark matter density. The result is a modulation of atomic transition energies. We point out a new time-domain signature of this effect in a type of gravitational wave detector that compares two spatially separated atom interferometers referenced by a common laser. Such a detector can improve on current searches for electron-mass or electric-charge modulus dark matter by up to 10 orders of magnitude in coupling, in a frequency band complementary to that of other proposals. It demonstrates that this class of atomic sensors is qualitatively different from other gravitational wave detectors, including those based on laser interferometry. By using atomic-clock-like interferometers, laser noise is mitigated with only a single baseline. These atomic sensors can thus detect scalar signals in addition to tensor signals.
Beyond seismic interferometry: imaging the earth's interior with virtual sources and receivers inside the earth

NASA Astrophysics Data System (ADS)

Wapenaar, C. P. A.; Van der Neut, J.; Thorbecke, J.; Broggini, F.; Slob, E. C.; Snieder, R.

2015-12-01

Imagine one could place seismic sources and receivers at any desired position inside the earth. Since the receivers would record the full wave field (direct waves, up- and downward reflections, multiples, etc.), this would give a wealth of information about the local structures, material properties and processes in the earth's interior. Although in reality one cannot place sources and receivers anywhere inside the earth, it appears to be possible to create virtual sources and receivers at any desired position, which accurately mimics the desired situation. The underlying method involves some major steps beyond standard seismic interferometry. With seismic interferometry, virtual sources can be created at the positions of physical receivers, assuming these receivers are illuminated isotropically. Our proposed method does not need physical receivers at the positions of the virtual sources; moreover, it does not require isotropic illumination. To create virtual sources and receivers anywhere inside the earth, it suffices to record the reflection response with physical sources and receivers at the earth's surface. We do not need detailed information about the medium parameters; it suffices to have an estimate of the direct waves between the virtual-source positions and the acquisition surface. With these prerequisites, our method can create virtual sources and receivers, anywhere inside the earth, which record the full wave field. The up- and downward reflections, multiples, etc. in the virtual responses are extracted directly from the reflection response at the surface. The retrieved virtual responses form an ideal starting point for accurate seismic imaging, characterization and monitoring.
Ambient Vibration and Earthquake-Data Analyses of a 62-STORY Building Using System Identification and Seismic Interferometry

NASA Astrophysics Data System (ADS)

Kalkan, E.; Fletcher, J. B.; Ulusoy, H. S.; Baker, L. A.

2014-12-01

A 62-story residential tower in San Francisco—the tallest all-residential building in California—was recently instrumented by the USGS's National Strong Motion Project in collaboration with the Strong Motion Instrumentation Program of the California Geological Survey to monitor the motion of a tall building built with specifically engineered features (including buckling-restrained braces, outrigger columns and a tuned liquid damper) to reduce its sway from seismic and wind loads. This 641-ft tower has been outfitted with 72 uni-axial accelerometers, spanning through 26 different levels of the building. For damage detection and localization through structural health monitoring, we use local micro-earthquake and ambient monitoring (background noises) to define linear-elastic (undamaged) dynamic properties of the superstructure including its modal parameters (fundamental frequencies, mode shapes and modal damping values) and shear-wave propagation profile and wave attenuation inside the building, which need to be determined in advance of strong shaking. In order to estimate the baseline modal parameters, we applied a frequency domain decomposition method. Using this method, the first three bending modes in the reference east-west direction, the first two bending modes in the reference north-south direction, and the first two torsional modes were identified. The shear-wave propagation and wave attenuation inside the building were computed using deconvolution interferometry. The data used for analyses are from ambient vibrations having 20 minutes duration, and earthquake data from a local M4.5 event located just north east of Geyserville, California. We show that application of deconvolution interferometry to data recorded inside a building is a powerful technique for monitoring structural parameters, such as velocities of traveling waves, frequencies of normal modes, and intrinsic attenuation (i.e., damping). The simplicity and similarity of the deconvolved waveforms from ambient vibrations and a small magnitude event also suggest that a one-dimensional shear velocity model is sufficiently accurate to represent the wave propagation charactersistics inside the building.
Amplitude and phase measurements based on low-coherence interferometry with acousto-optic spectral image filtration

NASA Astrophysics Data System (ADS)

Machikhin, Alexander; Burmak, Ludmila; Pozhar, Vitold

2018-04-01

The manuscript addresses the advantages and possible applications of acousto-optic image spectral filtration in lowcoherence interferometry. In particular, an effective operation of acousto-optical tunable filters in combination with Michelson-type interferometers is shown. The results of original experiments are presented. It is demonstrated that amplitude and phase spatial distributions of light waves reflected from or transmitted through the object can be fast determined in contactless manner for any spectral intervals with use of the presented techniques.
Design of a digital multiradian phase detector and its application in fusion plasma interferometry.

PubMed

Mlynek, A; Schramm, G; Eixenberger, H; Sips, G; McCormick, K; Zilker, M; Behler, K; Eheberg, J

2010-03-01

We discuss the circuit design of a digital multiradian phase detector that measures the phase difference between two 10 kHz square wave TTL signals and provides the result as a binary number. The phase resolution of the circuit is 1/64 period and its dynamic range is 256 periods. This circuit has been developed for fusion plasma interferometry with submillimeter waves on the ASDEX Upgrade tokamak. The results from interferometric density measurement are discussed and compared to those obtained with the previously used phase detectors, especially with respect to the occurrence of phase jumps. It is illustrated that the new phase measurement provides a powerful tool for automatic real-time validation of the measured density, which is important for feedback algorithms that are sensitive to spurious density signals.
Frequency selection for coda wave interferometry in concrete structures.

PubMed

Fröjd, Patrik; Ulriksen, Peter

2017-09-01

This study contributes to the establishment of frequency recommendations for use in coda wave interferometry structural health monitoring (SHM) systems for concrete structures. To this end, codas with widely different central frequencies were used to detect boreholes with different diameters in a large concrete floor slab, and to track increasing damage in a small concrete beam subjected to bending loads. SHM results were obtained for damage that can be simulated by drilled holes on the scale of a few mm or microcracks due to bending. These results suggest that signals in the range of 50-150kHz are suitable in large concrete structures where it is necessary to account for the high attenuation of high-frequency signals. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.
One-shot and aberration-tolerable homodyne detection for holographic storage readout through double-frequency grating-based lateral shearing interferometry.

PubMed

Yu, Yeh-Wei; Xiao, Shuai; Cheng, Chih-Yuan; Sun, Ching-Cherng

2016-05-16

A simple method to decode the stored phase signal of volume holographic data storage with adequate wave aberration tolerance is highly demanded. We proposed and demonstrated a one-shot scheme to decode a binary-phase encoding signal through double-frequency-grating based shearing interferometry (DFGSI). The lateral shearing amount is dependent on the focal length of the collimated lens and the frequency difference between the gratings. Diffracted waves with phase encoding were successfully decoded through experimentation. An optical model for the DFGSI was built to analyze phase-error induction and phase-difference control by shifting the double-frequency grating longitudinally and laterally, respectively. The optical model was demonstrated experimentally. Finally, a high aberration tolerance of the DFGSI was demonstrated using the optical model.
A LISA Interferometry Primer

NASA Technical Reports Server (NTRS)

Thorpe, James Ira

2010-01-01

A key challenge for all gravitational wave detectors in the detection of changes in the fractional difference between pairs of test masses with sufficient precision to measure astrophysical strains with amplitudes on the order of approx.10(exp -21). ln the case of the five million km arms of LISA, this equates to distance measurements on the ten picometer level. LISA interferometry utilizes a decentralized topology, in which each of the sciencecraft houses its own light sources, detectors, and electronics. The measurements made at each of the sciencecraft are then telemetered to ground and combined to extract the strain experienced by the constellation as a whole. I will present an overview of LISA interferometry and highlight some of the key components and technologies that make it possible.
Effect of hydrotherapy on recovery from fatigue.

PubMed

Vaile, J; Halson, S; Gill, N; Dawson, B

2008-07-01

The present study investigated the effects of three hydrotherapy interventions on next day performance recovery following strenuous training. Twelve cyclists completed four experimental trials differing only in 14-min recovery intervention: cold water immersion (CWI), hot water immersion (HWI), contrast water therapy (CWT), or passive recovery (PAS). Each trial comprised five consecutive exercise days of 105-min duration, including 66 maximal effort sprints. Additionally, subjects performed a total of 9-min sustained effort (time trial - TT). After completing each exercise session, athletes performed one of four recovery interventions (randomly assigned to each trial). Performance (average power), core temperature, heart rate (HR), and rating of perceived exertion (RPE) were recorded throughout each session. Sprint (0.1 - 2.2 %) and TT (0.0 - 1.7 %) performance were enhanced across the five-day trial following CWI and CWT, when compared to HWI and PAS. Additionally, differences in rectal temperature were observed between interventions immediately and 15-min post-recovery; however, no significant differences were observed in HR or RPE regardless of day of trial/intervention. Overall, CWI and CWT appear to improve recovery from high-intensity cycling when compared to HWI and PAS, with athletes better able to maintain performance across a five-day period.
A New Optical Bench Concept for Space-Based Laser Interferometric Gravitational Wave Missions

NASA Astrophysics Data System (ADS)

Chilton, Andrew; Apple, Stephen; Ciani, Giacomo; Olatunde, Taiwo; Conklin, John; Mueller, Guido

2015-04-01

Space-based interferometric gravitational wave detectors such as LISA have been proposed to detect low-frequency gravitational wave sources such as the inspirals of compact objects into massive black holes or two massive black holes into each other. The optical components used to perform the high-precision interferometry required to make these measurements have historically been bonded to Zerodur optical benches, which are thermally ultrastable but difficult and time-consuming to manufacture. More modern implementations of LISA-like interferometry have reduced the length stability requirement on these benches from 30fm/√{Hz} to a few pm √{ Hz}. We therefore propose to alter the design of the optical bench in such a way as to no longer require the use of Zerodur; instead, we plan to replace it with more easily-used materials such as titanium or molybdenum. In this presentation, we discuss the current status of and future plans for the construction and testing of such an optical bench.
Imaging of transient surface acoustic waves by full-field photorefractive interferometry.

PubMed

Xiong, Jichuan; Xu, Xiaodong; Glorieux, Christ; Matsuda, Osamu; Cheng, Liping

2015-05-01

A stroboscopic full-field imaging technique based on photorefractive interferometry for the visualization of rapidly changing surface displacement fields by using of a standard charge-coupled device (CCD) camera is presented. The photorefractive buildup of the space charge field during and after probe laser pulses is simulated numerically. The resulting anisotropic diffraction upon the refractive index grating and the interference between the polarization-rotated diffracted reference beam and the transmitted signal beam are modeled theoretically. The method is experimentally demonstrated by full-field imaging of the propagation of photoacoustically generated surface acoustic waves with a temporal resolution of nanoseconds. The surface acoustic wave propagation in a 23 mm × 17 mm area on an aluminum plate was visualized with 520 × 696 pixels of the CCD sensor, yielding a spatial resolution of 33 μm. The short pulse duration (8 ns) of the probe laser yields the capability of imaging SAWs with frequencies up to 60 MHz.
Full quantum mechanical analysis of atomic three-grating Mach–Zehnder interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanz, A.S., E-mail: asanz@iff.csic.es; Davidović, M.; Božić, M.

2015-02-15

Atomic three-grating Mach–Zehnder interferometry constitutes an important tool to probe fundamental aspects of the quantum theory. There is, however, a remarkable gap in the literature between the oversimplified models and robust numerical simulations considered to describe the corresponding experiments. Consequently, the former usually lead to paradoxical scenarios, such as the wave–particle dual behavior of atoms, while the latter make difficult the data analysis in simple terms. Here these issues are tackled by means of a simple grating working model consisting of evenly-spaced Gaussian slits. As is shown, this model suffices to explore and explain such experiments both analytically and numerically,more » giving a good account of the full atomic journey inside the interferometer, and hence contributing to make less mystic the physics involved. More specifically, it provides a clear and unambiguous picture of the wavefront splitting that takes place inside the interferometer, illustrating how the momentum along each emerging diffraction order is well defined even though the wave function itself still displays a rather complex shape. To this end, the local transverse momentum is also introduced in this context as a reliable analytical tool. The splitting, apart from being a key issue to understand atomic Mach–Zehnder interferometry, also demonstrates at a fundamental level how wave and particle aspects are always present in the experiment, without incurring in any contradiction or interpretive paradox. On the other hand, at a practical level, the generality and versatility of the model and methodology presented, makes them suitable to attack analogous problems in a simple manner after a convenient tuning. - Highlights: • A simple model is proposed to analyze experiments based on atomic Mach–Zehnder interferometry. • The model can be easily handled both analytically and computationally. • A theoretical analysis based on the combination of the position and momentum representations is considered. • Wave and particle aspects are shown to coexist within the same experiment, thus removing the old wave-corpuscle dichotomy. • A good agreement between numerical simulations and experimental data is found without appealing to best-fit procedures.« less
Elastic properties of transparent nano-polycrystalline diamond measured by GHz-ultrasonic interferometry and resonant sphere methods

NASA Astrophysics Data System (ADS)

Chang, Yun-Yuan; Jacobsen, Steven D.; Kimura, Masaki; Irifune, Tetsuo; Ohno, Ichiro

2014-03-01

The sound velocities and elastic moduli of transparent nano-polycrystalline diamond (NPD) have been determined by GHz-ultrasonic interferometry on three different bulk samples, and by resonant spectroscopy on a spherically fabricated NPD sample. We employ a newly-developed optical contact micrometer to measure the thickness of ultrasonic samples to ±0.05 μm with a spatial resolution of ∼50 μm in the same position of the GHz-ultrasonic measurements, resulting in acoustic-wave sound velocity measurements with uncertainties of 0.005-0.02%. The isotropic and adiabatic bulk and shear moduli of NPD measured by GHz-ultrasonic interferometry are KS0 = 442.5 (±0.5) GPa and G0 = 532.4 (±0.5) GPa. By rotating the shear-wave polarization direction, we observe no transverse anisotropy in this NPD. Using resonant sphere spectroscopy, we obtain KS0 = 440.3 (±0.5) GPa and G0 = 532.7 (±0.4) GPa. For comparison, we also measured by GHz-ultrasonic interferometry the elastic constants of a natural single-crystal type-IA diamond with about one-half the experimental uncertainty of previous measurements. The resulting Voigt-Reuss-Hill averaged bulk and shear moduli of natural diamond are KS0 = 441.8 (±0.8) GPa and G0 = 532.6 (±0.5) GPa, demonstrating that the bulk-elastic properties of transparent NPD are equivalent to natural single-crystal diamond as calculated from polycrystalline averaging of its elastic constants.
The use of holographic interferometry for measurements of temperature in a rectangular heat pipe. M.S. Thesis

NASA Technical Reports Server (NTRS)

Marn, Jure

1989-01-01

Holographic interferometry is a nonintrusive method and as such possesses considerable advantages such as not disturbing the velocity and temperature field by creating obstacles which would alter the flow field. These optical methods have disadvantages as well. Holography, as one of the interferometry methods, retains the accuracy of older methods, and at the same time eliminates the system error of participating components. The holographic interferometry consists of comparing the objective beam with the reference beam and observing the difference in lengths of optical paths, which can be observed during the propagation of the light through a medium with locally varying refractive index. Thus, change in refractive index can be observed as a family of nonintersecting surfaces in space (wave fronts). The object of the investigation was a rectangular heat pipe. The goal was to measure temperatures in the heat pipe, which yields data for computer code or model assessment. The results were obtained by calculating the temperatures by means of finite fringes.

Evaluation of the wave measurement in a stormy sea by the Along-Track interferometry SAR

NASA Astrophysics Data System (ADS)

Kojima, S.

2015-12-01

NICT developed the along-track interferometry SAR (AT-InSAR) system to detect the running cars and ships and measure sea surface velocity in 2011. The preliminary experiments for the running truck and ship were performed and it confirmed that the system performance was satisfactory to its specifications. In addition, a method to estimate the wave height from the sea surface velocity measured by the AT-InSAR was developed. The preliminary wave height observation was performed in a calm sea, and it was confirmed that the wave height could be estimated from the measured sea surface velocity. The purpose of this study is to check the capability of the ocean waves observation in a stormy sea by the AT-InSAR. Therefore, the ocean wave observation was performed under the low atmospheric pressure. The observation area is the sea surface at 10 km off the coast of Kushiro, south-east to Hokaido, JAPAN on the 4th of March 2015. The wind speed was 8〜10m/s during the observation, and the significant wave height and period were 1.5m and 6.0s. The observation was performed in 2 directions and the accuracy of the estimation results were checked. The significant wave height and period measured by the AT-InSAR agreed with it measured by the wave gage located close to this observation area. In addition, it was confirmed that there were no irregular wave heights in the distribution of the estimated wave height. As a result, it became clear that the AT-InSAR could observe the wave height in a stormy sea.
Combining Monte Carlo methods with coherent wave optics for the simulation of phase-sensitive X-ray imaging

PubMed Central

Peter, Silvia; Modregger, Peter; Fix, Michael K.; Volken, Werner; Frei, Daniel; Manser, Peter; Stampanoni, Marco

2014-01-01

Phase-sensitive X-ray imaging shows a high sensitivity towards electron density variations, making it well suited for imaging of soft tissue matter. However, there are still open questions about the details of the image formation process. Here, a framework for numerical simulations of phase-sensitive X-ray imaging is presented, which takes both particle- and wave-like properties of X-rays into consideration. A split approach is presented where we combine a Monte Carlo method (MC) based sample part with a wave optics simulation based propagation part, leading to a framework that takes both particle- and wave-like properties into account. The framework can be adapted to different phase-sensitive imaging methods and has been validated through comparisons with experiments for grating interferometry and propagation-based imaging. The validation of the framework shows that the combination of wave optics and MC has been successfully implemented and yields good agreement between measurements and simulations. This demonstrates that the physical processes relevant for developing a deeper understanding of scattering in the context of phase-sensitive imaging are modelled in a sufficiently accurate manner. The framework can be used for the simulation of phase-sensitive X-ray imaging, for instance for the simulation of grating interferometry or propagation-based imaging. PMID:24763652
Dual-wavelength, continuous-wave Yb:YAG laser for high-resolution photothermal common-path interferometry.

PubMed

Zhuang, Fengjiang; Jungbluth, Bernd; Gronloh, Bastian; Hoffmann, Hans-Dieter; Zhang, Ge

2013-07-20

We present a continuous-wave (CW) intracavity frequency-doubled Yb:YAG laser providing 1030 and 515 nm output simultaneously. This laser system was designed for photothermal common-path interferometry to measure spatially resolved profiles of the linear absorption in dielectric media and coatings for visible or infrared light as well as of the nonlinear absorption for the combination of both. A Z-shape laser cavity was designed, providing a beam waist in which an LBO crystal was located for effective second-harmonic generation (SHG). Suitable frequency conversion parameters and cavity configurations were discussed to achieve the optimal performance of a diode-pumped CW SHG laser. A 12.4 W 1030 nm laser and 5.4 W 515 nm laser were developed simultaneously in our experiment.
Estimation of seismic attenuation in carbonate rocks using three different methods: Application on VSP data from Abu Dhabi oilfield

NASA Astrophysics Data System (ADS)

Bouchaala, F.; Ali, M. Y.; Matsushima, J.

2016-06-01

In this study a relationship between the seismic wavelength and the scale of heterogeneity in the propagating medium has been examined. The relationship estimates the size of heterogeneity that significantly affects the wave propagation at a specific frequency, and enables a decrease in the calculation time of wave scattering estimation. The relationship was applied in analyzing synthetic and Vertical Seismic Profiling (VSP) data obtained from an onshore oilfield in the Emirate of Abu Dhabi, United Arab Emirates. Prior to estimation of the attenuation, a robust processing workflow was applied to both synthetic and recorded data to increase the Signal-to-Noise Ratio (SNR). Two conventional methods of spectral ratio and centroid frequency shift methods were applied to estimate the attenuation from the extracted seismic waveforms in addition to a new method based on seismic interferometry. The attenuation profiles derived from the three approaches demonstrated similar variation, however the interferometry method resulted in greater depth resolution, differences in attenuation magnitude. Furthermore, the attenuation profiles revealed significant contribution of scattering on seismic wave attenuation. The results obtained from the seismic interferometry method revealed estimated scattering attenuation ranges from 0 to 0.1 and estimated intrinsic attenuation can reach 0.2. The subsurface of the studied zones is known to be highly porous and permeable, which suggest that the mechanism of the intrinsic attenuation is probably the interactions between pore fluids and solids.
Comparison of the results of refractometric measurements in the process of diffusion, obtained by means of the backgroundoriented schlieren method and the holographic interferometry method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraiskii, A V; Mironova, T V

2015-08-31

The results of the study of interdiffusion of two liquids, obtained using the holographic recording scheme with a nonstationary reference wave with the frequency linearly varying in space and time are compared with the results of correlation processing of digital photographs, made with a random background screen. The spatio-temporal behaviour of the signal in four basic representations ('space – temporal frequency', 'space – time', 'spatial frequency – temporal frequency' and 'spatial frequency – time') is found in the holographic experiment and calculated (in the appropriate coordinates) based on the background-oriented schlieren method. Practical coincidence of the results of the correlationmore » analysis and the holographic double-exposure interferometry is demonstrated. (interferometry)« less
Upper Crustal Structure of Taiwan Constrained by the Ellipticity of the Noise-derived Rayleigh Waves

NASA Astrophysics Data System (ADS)

Chien, C. C.; Chen, Y. N.; Gung, Y.; Liang, W. T.

2016-12-01

In the last decade, the noise interferometry has been a popular technique, and widely applied to constraint the crust and uppermost mantle structure, bringing in revolutionary resolution in area with dense seismic network, including Taiwan. However, limited by the available frequency band of the noise-derived surface waves, the near surface (<5km) structure is much less resolved as compared to the rest of the crust in Taiwan. Such limitation may be lifted by using the ZH ratio of Rayleigh waves, because, for the same period, the ZH ratio of Rayleigh waves is much more sensitive to the shallower structure than those provided by the corresponding phase or group velocities. In this study, aiming to better constraint the seismic structure of the shallow crust of Taiwan, we measure the ZH ratios of the Rayleigh waves derived by noise interferometry. Continuous records from two major seismic networks in Taiwan are used. In total, data from 63 short period stations and 48 broadband stations are used to derived the four combinations (ZZ, ZR, RZ, RR) of cross-correlation functions (CCF). We then measure the ZH ratios of the derived Rayleigh waves. We present the measured results, invert for the local 1-D structure for sites with stable measurements. We then compare the results with the published tomographic models and discuss their geological implications.
Gravitational wave detection using laser interferometry beyond the standard quantum limit

NASA Astrophysics Data System (ADS)

Heurs, M.

2018-05-01

Interferometric gravitational wave detectors (such as advanced LIGO) employ high-power solid-state lasers to maximize their detection sensitivity and hence their reach into the universe. These sophisticated light sources are ultra-stabilized with regard to output power, emission frequency and beam geometry; this is crucial to obtain low detector noise. However, even when all laser noise is reduced as far as technically possible, unavoidable quantum noise of the laser still remains. This is a consequence of the Heisenberg Uncertainty Principle, the basis of quantum mechanics: in this case, it is fundamentally impossible to simultaneously reduce both the phase noise and the amplitude noise of a laser to arbitrarily low levels. This fact manifests in the detector noise budget as two distinct noise sources-photon shot noise and quantum radiation pressure noise-which together form a lower boundary for current-day gravitational wave detector sensitivities, the standard quantum limit of interferometry. To overcome this limit, various techniques are being proposed, among them different uses of non-classical light and alternative interferometer topologies. This article explains how quantum noise enters and manifests in an interferometric gravitational wave detector, and gives an overview of some of the schemes proposed to overcome this seemingly fundamental limitation, all aimed at the goal of higher gravitational wave event detection rates. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.
Gravitational wave detection using laser interferometry beyond the standard quantum limit.

PubMed

Heurs, M

2018-05-28

Interferometric gravitational wave detectors (such as advanced LIGO) employ high-power solid-state lasers to maximize their detection sensitivity and hence their reach into the universe. These sophisticated light sources are ultra-stabilized with regard to output power, emission frequency and beam geometry; this is crucial to obtain low detector noise. However, even when all laser noise is reduced as far as technically possible, unavoidable quantum noise of the laser still remains. This is a consequence of the Heisenberg Uncertainty Principle, the basis of quantum mechanics: in this case, it is fundamentally impossible to simultaneously reduce both the phase noise and the amplitude noise of a laser to arbitrarily low levels. This fact manifests in the detector noise budget as two distinct noise sources-photon shot noise and quantum radiation pressure noise-which together form a lower boundary for current-day gravitational wave detector sensitivities, the standard quantum limit of interferometry. To overcome this limit, various techniques are being proposed, among them different uses of non-classical light and alternative interferometer topologies. This article explains how quantum noise enters and manifests in an interferometric gravitational wave detector, and gives an overview of some of the schemes proposed to overcome this seemingly fundamental limitation, all aimed at the goal of higher gravitational wave event detection rates.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).
Atom Interferometry in a Warm Vapor

DOE PAGES

Biedermann, G. W.; McGuinness, H. J.; Rakholia, A. V.; ...

2017-04-17

Here, we demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. Lastly, this interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.
Status of the LISA On Table experiment: a electro-optical simulator for LISA

NASA Astrophysics Data System (ADS)

Laporte, M.; Halloin, H.; Bréelle, E.; Buy, C.; Grüning, P.; Prat, P.

2017-05-01

The LISA project is a space mission that aim at detecting gravitational waves in space. An electro-optical simulator called LISA On Table (LOT) is being developed at APC in order to test noise reduction techniques (such as Timed Delayed Interferometry) and instruments that will be used. This document presents its latest results: TimeDelayed Interferometry of 1st generation works in the case of a simulated white noise with static, unequal arms. Future and ongoing developments of the experiment are also addressed.
A Conserved Non-Canonical Docking Mechanism Regulates the Binding of Dual Specificity Phosphatases to Cell Integrity Mitogen-Activated Protein Kinases (MAPKs) in Budding and Fission Yeasts

PubMed Central

Sacristán-Reviriego, Almudena; Madrid, Marisa; Cansado, José; Martín, Humberto; Molina, María

2014-01-01

Dual-specificity MAPK phosphatases (MKPs) are essential for the negative regulation of MAPK pathways. Similar to other MAPK-interacting proteins, most MKPs bind MAPKs through specific docking domains known as D-motifs. However, we found that the Saccharomyces cerevisiae MKP Msg5 binds the MAPK Slt2 within the cell wall integrity (CWI) pathway through a distinct motif (IYT). Here, we demonstrate that the IYT motif mediates binding of the Msg5 paralogue Sdp1 to Slt2 as well as of the MKP Pmp1 to its CWI MAPK counterpart Pmk1 in the evolutionarily distant yeast Schizosaccharomyces pombe. As a consequence, removal of the IYT site in Msg5, Sdp1 and Pmp1 reduces MAPK trapping caused by the overexpression of catalytically inactive versions of these phosphatases. Accordingly, an intact IYT site is necessary for inactive Sdp1 to prevent nuclear accumulation of Slt2. We also show that both Ile and Tyr but not Thr are essential for the functionality of the IYT motif. These results provide mechanistic insight into MKP-MAPK interplay and stress the relevance of this conserved non-canonical docking site in the regulation of the CWI pathway in fungi. PMID:24465549
Impact of resistance exercise on ribosome biogenesis is acutely regulated by post-exercise recovery strategies.

PubMed

Figueiredo, Vandré C; Roberts, Llion A; Markworth, James F; Barnett, Matthew P G; Coombes, Jeff S; Raastad, Truls; Peake, Jonathan M; Cameron-Smith, David

2016-02-01

Muscle hypertrophy occurs following increased protein synthesis, which requires activation of the ribosomal complex. Additionally, increased translational capacity via elevated ribosomal RNA (rRNA) synthesis has also been implicated in resistance training-induced skeletal muscle hypertrophy. The time course of ribosome biogenesis following resistance exercise (RE) and the impact exerted by differing recovery strategies remains unknown. In the present study, the activation of transcriptional regulators, the expression levels of pre-rRNA, and mature rRNA components were measured through 48 h after a single-bout RE. In addition, the effects of either low-intensity cycling (active recovery, ACT) or a cold-water immersion (CWI) recovery strategy were compared. Nine male subjects performed two bouts of high-load RE randomized to be followed by 10 min of either ACT or CWI. Muscle biopsies were collected before RE and at 2, 24, and 48 h after RE. RE increased the phosphorylation of the p38-MNK1-eIF4E axis, an effect only evident with ACT recovery. Downstream, cyclin D1 protein, total eIF4E, upstream binding factor 1 (UBF1), and c-Myc proteins were all increased only after RE with ACT. This corresponded with elevated abundance of the pre-rRNAs (45S, ITS-28S, ITS-5.8S, and ETS-18S) from 24 h after RE with ACT. In conclusion, coordinated upstream signaling and activation of transcriptional factors stimulated pre-rRNA expression after RE. CWI, as a recovery strategy, markedly blunted these events, suggesting that suppressed ribosome biogenesis may be one factor contributing to the impaired hypertrophic response observed when CWI is used regularly after exercise. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1.

PubMed

Elsztein, Carolina; de Lucena, Rodrigo M; de Morais, Marcos A

2011-08-19

Polyhexamethylene biguanide (PHMB) is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating Acantamoeba infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of Saccharomyces cerevisiae, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound. In this study, we examined the factors involved in PHMB-cell interaction and the mechanisms that respond to the damage caused by this interaction. To achieve this, two research strategies were employed: the expression of some genes by RT-qPCR and the analysis of mutant strains. Cell Wall integrity (CWI) genes were induced in the PHMB-resistant Saccharomyces cerevisiae strain JP-1, although they are poorly expressed in the PHMB-sensitive Saccharomyces cerevisiae PE2 strain. This suggested that PHMB damages the glucan structure on the yeast cell wall. It was also confirmed by the observed sensitivity of the yeast deletion strains, Δslg1, Δrom2, Δmkk2, Δslt2, Δknr4, Δswi4 and Δswi4, which showed that the protein kinase C (PKC) regulatory mechanism is involved in the response and resistance to PHMB. The sensitivity of the Δhog1 mutant was also observed. Furthermore, the cytotoxicity assay and gene expression analysis showed that the part played by YAP1 and CTT1 genes in cell resistance to PHMB is unrelated to oxidative stress response. Thus, we suggested that Yap1p can play a role in cell wall maintenance by controlling the expression of the CWI genes. The PHMB treatment of the yeast cells activates the PKC1/Slt2 (CWI) pathway. In addition, it is suggested that HOG1 and YAP1 can play a role in the regulation of CWI genes.
Post-exercise recovery of biological, clinical and metabolic variables after different temperatures and durations of cold water immersion: a randomized clinical trial.

PubMed

Vanderlei, Franciele M; de Albuquerque, Maíra C; de Almeida, Aline C; Machado, Aryane F; Netto, Jayme; Pastre, Carlos M

2017-10-01

Cold water immersion (CWI) is a commonly used recuperative strategy. However there is a lack of standardization of protocols considering the duration and temperature of application of the technique and the stress model. Therefore it is important to study the issue of dose response in a specific stress model. Thus the objective was to analyze and compare the effects of CWI during intense post-exercise recovery using different durations and temperatures of immersion. One hundred and five male individuals were divided into five groups: one control group (CG) and four recovery groups (G1: 5' at 9±1 °C; G2: 5' at 14±1 °C; G3: 15' at 9±1 °C; G4: 15' at 14±1 °C). The volunteers were submitted to an exhaustion protocol that consisted of a jump program and the Wingate Test. Immediately after the exhaustion protocol, the volunteers were directed to a tank with water and ice, where they were immersed for the recovery procedure, during which blood samples were collected for later lactate and creatine kinase (CK) analysis. Variables were collected prior to the exercise and 24, 48, 72, and 96 hours after its completion. For the CK concentration, 15 minutes at 14 °C was the best intervention option, considering the values at 72 hours after exercise, while for the moment of peak lactate an advantage was observed for immersion for 5 minutes at 14 °C. Regarding the perception of recovery, CWI for 5 minutes at 14 °C performed better long-term, from the time of the intervention to 96 hours post-exercise. For pain, no form of immersion responded better than the CG at the immediately post-intervention moment. There were no differences in behavior between the CWI intervention groups for the outcomes studied.
Effects of β-hydroxy-β-methylbutyrate free acid and cold water immersion on expression of CR3 and MIP-1β following resistance exercise.

PubMed

Gonzalez, Adam M; Fragala, Maren S; Jajtner, Adam R; Townsend, Jeremy R; Wells, Adam J; Beyer, Kyle S; Boone, Carleigh H; Pruna, Gabriel J; Mangine, Gerald T; Bohner, Jonathan D; Fukuda, David H; Stout, Jeffrey R; Hoffman, Jay R

2014-04-01

The inflammatory response to muscle-damaging exercise requires monocyte mobilization and adhesion. Complement receptor type 3 (CR3) and macrophage inflammatory protein (MIP)-1β enables monocyte recruitment, adhesion, and subsequent infiltration into damaged muscle tissue. The purpose of this study was to examine the effects of cold water immersion (CWI) and/or β-hydroxy-β-methylbutyrate free acid (HMB-FA) on CR3 expression and MIP-1β concentration after four sets of up to 10 repetitions of squat, dead lift, and split squat exercises at 70-80% 1-repetition maximum. Thirty-nine resistance-trained men (22.2 ± 2.5 yr) were randomly divided into four groups: 1) placebo (PL), 2) HMB-FA, 3) HMB-FA-CWI, and 4) PL-CWI. The HMB-FA groups ingested 3 g/day, and CWI groups were submersed into 10-12°C water for 10 min after exercise. Blood was sampled at baseline (PRE), immediately post- (IP), 30 min post- (30P), 24 h post- (24P), and 48 h post (48P)-exercise. Circulating MIP-1β was assayed and CR3 expression on CD14+ monocytes was measured by flow cytometry. Without treatment, CR3 expression significantly elevated at 30P compared with other time points (P = 0.030-0.047). HMB-FA significantly elevated the percentage of monocytes expressing CR3 between IP and 24P (P = 0.046) and between IP and 48P (P = 0.046). No time effect was observed for MIP-1β concentration. The recovery modalities showed to attenuate the rise in CR3 following exercise. Additionally, supplementation with HMB-FA significantly elevated the percentage of monocytes expressing CR3 during recovery. Although the time course that inflammatory responses are most beneficial remains to be determined, recovery modalities may alter immune cell mobilization and adhesion mechanisms during tissue recovery.
The Effects of Multiple Cold Water Immersions on Indices of Muscle Damage

PubMed Central

Goodall, Stuart; Howatson, Glyn

2008-01-01

The aim of this investigation was to elucidate the efficacy of repeated cold water immersions (CWI) in the recovery of exercise induced muscle damage. A randomised group consisting of eighteen males, mean ± s age, height and body mass were 24 ± 5 years, 1.82 ± 0.06 m and 85.7 ± 16.6 kg respectively, completed a bout of 100 drop jumps. Following the bout of damaging exercise, participants were randomly but equally assigned to either a 12 min CWI (15 ± 1 °C; n = 9) group who experienced immersions immediately post-exercise and every 24 h thereafter for the following 3 days, or a control group (no treatment; n = 9). Maximal voluntary contraction (MVC) of the knee extensors, creatine kinase activity (CK), muscle soreness (DOMS), range of motion (ROM) and limb girth were measured pre-exercise and then for the following 96 h at 24 h increments. In addition MVC was also recorded immediately post-exercise. Significant time effects were seen for MVC, CK, DOMS and limb girth (p < 0.05) indicating muscle damage was evident, however there was no group effect or interaction observed showing that CWI did not attenuate any of the dependent variables (p > 0.05). These results suggest that repeated CWI do not enhance recovery from a bout of damaging eccentric contractions. Key pointsCryotherapy, particularly cold water immersions are one of the most common interventions used in order to enhance recovery post-exercise.There is little empirical evidence demonstrating benefits from cold water immersions. Research evidence is equivocal, probably due to methodological inconsistencies.Our results show that the cryotherapy administered did not attenuate any markers of EIMD or enhance the recovery of function.We conclude that repeated cold water immersions are ineffective in the recovery from heavy plyometric exercise and suggest athletes and coaches should use caution before using this intervention as a recovery strategy PMID:24149455
Optical fiber interferometer for the study of ultrasonic waves in composite materials

NASA Technical Reports Server (NTRS)

Claus, R. O.; Zewekh, P. S.; Turner, T. M.; Wade, J. C.; Rogers, R. T.; Garg, A. O.

1981-01-01

The possibility of acoustic emission detection in composites using embedded optical fibers as sensing elements was investigated. Optical fiber interferometry, fiber acoustic sensitivity, fiber interferometer calibration, and acoustic emission detection are reported. Adhesive bond layer dynamical properties using ultrasonic interface waves, the design and construction of an ultrasonic transducer with a two dimensional Gaussian pressure profile, and the development of an optical differential technique for the measurement of surface acoustic wave particle displacements and propagation direction are also examined.
Quantum noise limits to matter-wave interferometry

NASA Technical Reports Server (NTRS)

Scully, Marlan O.; Dowling, Jonathan P.

1994-01-01

We derive the quantum limits for an atomic interferometer in which the atoms obey either Bose-Einstein or Fermi-Dirac statistics. It is found that the limiting quantum noise is due to the uncertainty associated with the particle sorting between the two branches of the interferometer. As an example, the quantum-limited sensitivity of a matter-wave gyroscope is calculated and compared with that of laser gyroscopes.
Phase-sensitive X-ray imager

DOEpatents

Baker, Kevin Louis

2013-01-08

X-ray phase sensitive wave-front sensor techniques are detailed that are capable of measuring the entire two-dimensional x-ray electric field, both the amplitude and phase, with a single measurement. These Hartmann sensing and 2-D Shear interferometry wave-front sensors do not require a temporally coherent source and are therefore compatible with x-ray tubes and also with laser-produced or x-pinch x-ray sources.
Wave packet interferometry and quantum state reconstruction by acousto-optic phase modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tekavec, Patrick F.; Dyke, Thomas R.; Marcus, Andrew H.

2006-11-21

Studies of wave packet dynamics often involve phase-selective measurements of coherent optical signals generated from sequences of ultrashort laser pulses. In wave packet interferometry (WPI), the separation between the temporal envelopes of the pulses must be precisely monitored or maintained. Here we introduce a new (and easy to implement) experimental scheme for phase-selective measurements that combines acousto-optic phase modulation with ultrashort laser excitation to produce an intensity-modulated fluorescence signal. Synchronous detection, with respect to an appropriately constructed reference, allows the signal to be simultaneously measured at two phases differing by 90 deg. Our method effectively decouples the relative temporal phasemore » from the pulse envelopes of a collinear train of optical pulse pairs. We thus achieve a robust and high signal-to-noise scheme for WPI applications, such as quantum state reconstruction and electronic spectroscopy. The validity of the method is demonstrated, and state reconstruction is performed, on a model quantum system - atomic Rb vapor. Moreover, we show that our measurements recover the correct separation between the absorptive and dispersive contributions to the system susceptibility.« less

Pixel level optical-transfer-function design based on the surface-wave-interferometry aperture

PubMed Central

Zheng, Guoan; Wang, Yingmin; Yang, Changhuei

2010-01-01

The design of optical transfer function (OTF) is of significant importance for optical information processing in various imaging and vision systems. Typically, OTF design relies on sophisticated bulk optical arrangement in the light path of the optical systems. In this letter, we demonstrate a surface-wave-interferometry aperture (SWIA) that can be directly incorporated onto optical sensors to accomplish OTF design on the pixel level. The whole aperture design is based on the bull’s eye structure. It composes of a central hole (diameter of 300 nm) and periodic groove (period of 560 nm) on a 340 nm thick gold layer. We show, with both simulation and experiment, that different types of optical transfer functions (notch, highpass and lowpass filter) can be achieved by manipulating the interference between the direct transmission of the central hole and the surface wave (SW) component induced from the periodic groove. Pixel level OTF design provides a low-cost, ultra robust, highly compact method for numerous applications such as optofluidic microscopy, wavefront detection, darkfield imaging, and computational photography. PMID:20721038
P and S Velocity Structure in the Groningen Gas Reservoir From Noise Interferometry

NASA Astrophysics Data System (ADS)

Zhou, Wen; Paulssen, Hanneke

2017-12-01

Noise interferometry has proven to be a powerful tool to image seismic structure. In this study we used data from 10 geophones located in a borehole at ˜3 km depth within the Groningen gas reservoir in the Netherlands. The continuous data cross correlations show that noise predominantly comes in from above. The observed daily and weekly variations further indicate that the noise has an anthropogenic origin. The direct P wave emerges from the stacked vertical component cross correlations with frequencies up to 80 Hz and the direct S wave is retrieved from the horizontal components with frequencies up to 50 Hz. The measured intergeophone travel times were used to retrieve the P and S velocity structure along the borehole, and a good agreement was found with well log data. In addition, from the S wave polarizations, we determined azimuthal anisotropy with a fast direction of N65°W±18° and an estimated magnitude of (4±2)%. The fast polarization direction corresponds to the present direction of maximum horizontal stress measured at nearby boreholes but is also similar to the estimated paleostress direction.
Monitoring the Groningen gas field by seismic noise interferometry

NASA Astrophysics Data System (ADS)

Zhou, Wen; Paulssen, Hanneke

2017-04-01

The Groningen gas field in the Netherlands is the world's 7th largest onshore gas field and has been producing from 1963. Since 2013, the year with the highest level of induced seismicity, the reservoir has been monitored by two geophone strings at reservoir level at about 3 km depth. For borehole SDM, 10 geophones with a natural frequency of 15-Hz are positioned from the top to bottom of the reservoir with a geophone spacing of 30 m. We used seismic interferometry to determine, as accurately as possible, the inter-geophone P- and S-wave velocities from ambient noise. We used 1-bit normalization and spectral whitening, together with a bandpass filter from 3 to 400 Hz. After that, for each station pair, the normalized cross-correlation was calculated for 6 seconds segments with 2/3 overlap. These segmented cross-correlations were stacked for every 1 hour, 24(hours)*33(days) segments were obtained for each station pair. The cross-correlations show both day-and-night and weekly variations reflecting fluctuations in cultural noise. The apparent P-wave travel time for each geophone pair is measured from the maximum of the vertical component cross-correlation for each of the hourly stacks. Because the distribution of these (24*33) picked travel times is not Gaussian but skewed, we used Kernel density estimations to obtain probability density functions of the travel times. The maximum likelihood travel times of all the geophone pairs was subsequently used to determine inter-geophone P-wave velocities. A good agreement was found between our estimated P velocity structure and well logging data, with difference less than 5%. The S-velocity structure was obtained from the east-component cross-correlations. They show both the direct P- and S-wave arrivals and, because of the interference, the inferred S-velocity structure is less accurate. From the 9(3x3)-component cross-correlations for all the geophone pairs, not only the direct P and S waves can be identified, but also reflected waves within the reservoir for some of the cross-correlations. It is concluded that noise interferometry can be used to determine the seismic velocity structure from deep borehole data.
Tone-assisted time delay interferometry on GRACE Follow-On

NASA Astrophysics Data System (ADS)

Francis, Samuel P.; Shaddock, Daniel A.; Sutton, Andrew J.; de Vine, Glenn; Ware, Brent; Spero, Robert E.; Klipstein, William M.; McKenzie, Kirk

2015-07-01

We have demonstrated the viability of using the Laser Ranging Interferometer on the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) space mission to test key aspects of the interspacecraft interferometry proposed for detecting gravitational waves. The Laser Ranging Interferometer on GRACE-FO will be the first demonstration of interspacecraft interferometry. GRACE-FO shares many similarities with proposed space-based gravitational wave detectors based on the Laser Interferometer Space Antenna (LISA) concept. Given these similarities, GRACE-FO provides a unique opportunity to test novel interspacecraft interferometry techniques that a LISA-like mission will use. The LISA Experience from GRACE-FO Optical Payload (LEGOP) is a project developing tests of arm locking and time delay interferometry (TDI), two frequency stabilization techniques, that could be performed on GRACE-FO. In the proposed LEGOP TDI demonstration one GRACE-FO spacecraft will have a free-running laser while the laser on the other spacecraft will be locked to a cavity. It is proposed that two one-way interspacecraft phase measurements will be combined with an appropriate delay in order to produce a round-trip, dual one-way ranging (DOWR) measurement independent of the frequency noise of the free-running laser. This paper describes simulated and experimental tests of a tone-assisted TDI ranging (TDIR) technique that uses a least-squares fitting algorithm and fractional-delay interpolation to find and implement the delays needed to form the DOWR TDI combination. The simulation verifies tone-assisted TDIR works under GRACE-FO conditions. Using simulated GRACE-FO signals the tone-assisted TDIR algorithm estimates the time-varying interspacecraft range with a rms error of ±0.2 m , suppressing the free-running laser frequency noise by 8 orders of magnitude. The experimental results demonstrate the practicability of the technique, measuring the delay at the 6 ns level in the presence of a significant displacement signal.
Real-time trichromatic holographic interferometry: preliminary study

NASA Astrophysics Data System (ADS)

Albe, Felix; Bastide, Myriam; Desse, Jean-Michel; Tribillon, Jean-Louis H.

1998-08-01

In this paper we relate our preliminary experiments on real- time trichromatic holographic interferometry. For this purpose a CW `white' laser (argon and krypton of Coherent- Radiation, Spectrum model 70) is used. This laser produces about 10 wavelengths. A system consisting of birefringent plates and polarizers allows to select a trichromatic TEM00 triplet: blue line ((lambda) equals 476 nm, 100 mW), green line ((lambda) equals 514 nm, 100 mW) and red line ((lambda) equals 647 nm, 100 mW). In a first stage we recorded a trichromatic reflection hologram with a separate reference beam on a single-layer silver-halide panchromatic plate (PFG 03C). After processing, the hologram is put back into the original recording set-up, as in classical experiments on real-time monochromatic holographic interferometry. So we observe interference fringes between the 3 reconstructed waves and the 3 actual waves. The interference fringes of the phenomenon are observed on a screen and recorded by a video camera at 25 frames per second. A color video film of about 3 minutes of duration is presented. Some examples related to phase objects are presented (hot airflow from a candle, airflow from a hand). The actual results show the possibility of using this technique to study, in real time, aerodynamic wakes and mechanical deformation.
Coherent properties of a tunable low-energy electron-matter-wave source

NASA Astrophysics Data System (ADS)

Pooch, A.; Seidling, M.; Kerker, N.; Röpke, R.; Rembold, A.; Chang, W. T.; Hwang, I. S.; Stibor, A.

2018-01-01

A general challenge in various quantum experiments and applications is to develop suitable sources for coherent particles. In particular, recent progress in microscopy, interferometry, metrology, decoherence measurements, and chip-based applications rely on intensive, tunable, coherent sources for free low-energy electron-matter waves. In most cases, the electrons get field emitted from a metal nanotip, where its radius and geometry toward a counter electrode determines the field distribution and the emission voltage. A higher emission is often connected to faster electrons with smaller de Broglie wavelengths, requiring larger pattern magnification after matter-wave diffraction or interferometry. This can be prevented with a well-known setup consisting of two counter electrodes that allow independent setting of the beam intensity and velocity. However, it needs to be tested if the coherent properties of such a source are preserved after the acceleration and deceleration of the electrons. Here, we study the coherence of the beam in a biprism interferometer with a single atom tip electron field emitter if the particle velocity and wavelength varies after emission. With a Wien filter measurement and a contrast correlation analysis we demonstrate that the intensity of the source at a certain particle wavelength can be enhanced up to a factor of 6.4 without changing the transverse and longitudinal coherence of the electron beam. In addition, the energy width of the single atom tip emitter was measured to be 377 meV, corresponding to a longitudinal coherence length of 82 nm. The design has potential applications in interferometry, microscopy, and sensor technology.
Bringing mirrors to rest: grating concepts for ultra-precise interferometry

NASA Astrophysics Data System (ADS)

Kroker, Stefanie; Kley, Ernst-Bernhard; Tünnermann, Andreas

2015-02-01

Experiments in the field of high precision metrology such as the detection of gravitational waves are crucially limited by the thermal fluctuations of the optical components. In this contribution we present the current state of knowledge of high contrast gratings (HCGs) as low-noise elements for gravitational wave interferometers. We discuss how the properties of HCGs can be tailored such that beside highly reflective mirrors also diffractive beam splitters can be realized. Further, we show the impact of such gratings on the sensitivity of future gravitational wave detectors which can pave the way for the new field of gravitational wave astronomy.
Three-wave electron vortex lattices for measuring nanofields.

PubMed

Dwyer, C; Boothroyd, C B; Chang, S L Y; Dunin-Borkowski, R E

2015-01-01

It is demonstrated how an electron-optical arrangement consisting of two electron biprisms can be used to generate three-wave vortex lattices with effective lattice spacings between 0.1 and 1 nm. The presence of vortices in these lattices was verified by using a third biprism to perform direct phase measurements via off-axis electron holography. The use of three-wave lattices for nanoscale electromagnetic field measurements via vortex interferometry is discussed, including the accuracy of vortex position measurements and the interpretation of three-wave vortex lattices in the presence of partial spatial coherence. Copyright © 2014 Elsevier B.V. All rights reserved.
Development of phase detection schemes based on surface plasmon resonance using interferometry.

PubMed

Kashif, Muhammad; Bakar, Ahmad Ashrif A; Arsad, Norhana; Shaari, Sahbudin

2014-08-28

Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors.
Development of Phase Detection Schemes Based on Surface Plasmon Resonance Using Interferometry

PubMed Central

Kashif, Muhammad; Bakar, Ahmad Ashrif A.; Arsad, Norhana; Shaari, Sahbudin

2014-01-01

Surface plasmon resonance (SPR) is a novel optical sensing technique with a unique ability to monitor molecular binding in real-time for biological and chemical sensor applications. Interferometry is an excellent tool for accurate measurement of SPR changes, the measurement and comparison is made for the sensitivity, dynamic range and resolution of the different analytes using interferometry techniques. SPR interferometry can also employ phase detection in addition to the amplitude of the reflected light wave, and the phase changes more rapidly compared with other approaches, i.e., intensity, angle and wavelength. Therefore, the SPR phase interferometer offers the advantages of spatial phase resolution and high sensitivity. This work discusses the advancements in interferometric SPR methods to measure the phase shifts due to refractive index changes. The main application areas of SPR sensors are demonstrated, i.e., the Fabry-Perot interferometer, Michelson interferometer and Mach-Zehnder interferometer, with different configurations. The three interferometers are discussed in detail, and solutions are suggested to enhance the performance parameters that will aid in future biological and chemical sensors. PMID:25171117
Highly sensitive atomic based MW interferometry.

PubMed

Shylla, Dangka; Nyakang'o, Elijah Ogaro; Pandey, Kanhaiya

2018-06-06

We theoretically study a scheme to develop an atomic based micro-wave (MW) interferometry using the Rydberg states in Rb. Unlike the traditional MW interferometry, this scheme is not based upon the electrical circuits, hence the sensitivity of the phase and the amplitude/strength of the MW field is not limited by the Nyquist thermal noise. Further, this system has great advantage due to its much higher frequency range in comparision to the electrical circuit, ranging from radio frequency (RF), MW to terahertz regime. In addition, this is two orders of magnitude more sensitive to field strength as compared to the prior demonstrations on the MW electrometry using the Rydberg atomic states. Further, previously studied atomic systems are only sensitive to the field strength but not to the phase and hence this scheme provides a great opportunity to characterize the MW completely including the propagation direction and the wavefront. The atomic based MW interferometry is based upon a six-level loopy ladder system involving the Rydberg states in which two sub-systems interfere constructively or destructively depending upon the phase between the MW electric fields closing the loop. This work opens up a new field i.e. atomic based MW interferometry replacing the conventional electrical circuit in much superior fashion.
A proposed atom interferometry determination of G at 10-5 using a cold atomic fountain

NASA Astrophysics Data System (ADS)

Rosi, G.

2018-02-01

In precision metrology, the determination of the Newtonian gravity constant G represents a real problem, since its history is plagued by huge unknown discrepancies between a large number of independent experiments. In this paper, we propose a novel experimental setup for measuring G with a relative accuracy of 10-5 , using a standard cold atomic fountain and matter wave interferometry. We discuss in detail the major sources of systematic errors, and provide the expected statistical uncertainty. The feasibility of determining G at the 10-6 level is also discussed.
Bounds on quantum collapse models from matter-wave interferometry: calculational details

NASA Astrophysics Data System (ADS)

Toroš, Marko; Bassi, Angelo

2018-03-01

We present a simple derivation of the interference pattern in matter-wave interferometry predicted by a class of quantum master equations. We apply the obtained formulae to the following collapse models: the Ghirardi-Rimini-Weber (GRW) model, the continuous spontaneous localization (CSL) model together with its dissipative (dCSL) and non-Markovian generalizations (cCSL), the quantum mechanics with universal position localization (QMUPL), and the Diósi-Penrose (DP) model. We discuss the separability of the dynamics of the collapse models along the three spatial directions, the validity of the paraxial approximation, and the amplification mechanism. We obtain analytical expressions both in the far field and near field limits. These results agree with those already derived in the Wigner function formalism. We compare the theoretical predictions with the experimental data from two recent matter-wave experiments: the 2012 far-field experiment of Juffmann T et al (2012 Nat. Nanotechnol. 7 297-300) and the 2013 Kapitza-Dirac-Talbot-Lau (KDTL) near-field experiment of Eibenberger et al (2013 Phys. Chem. Chem. Phys. 15 14696-700). We show the region of the parameter space for each collapse model that is excluded by these experiments. We show that matter-wave experiments provide model-insensitive bounds that are valid for a wide family of dissipative and non-Markovian generalizations.
Comparison of Whole-Body Cooling Techniques for Athletes and Military Personnel.

PubMed

Nye, Emma A; Eberman, Lindsey E; Games, Kenneth E; Carriker, Colin

2017-01-01

The purpose of this study was to evaluate cooling rates of The Polar Life Pod ® , a military protocol and cold water immersion. A randomized, repeated measures design was used to compare three treatment options. Participants exercised in an environmental chamber, where they followed a military march protocol on a treadmill, followed by the application of one of three treatments: Cold water immersion tub (5 - 10 °C), Polar Life Pod® (5 - 10 °C), Ice sheets at onset (5 - 10 °C). Mean cooling rate for CWI was 0.072 ºC/min, 0.046ºC/min for ice sheets, and 0.040ºC/min for The Polar Life Pod ® . There was a significant difference between conditions (F2,26=13.564, p=0.001, ES=0.511, 1-β=0.969). There was a significant difference in cooling rate among The Polar Life Pod ® and CWI (p = 0.006), and no significant difference among The Polar Life Pod ® and Ice Sheets (p = 0.103). There was a significant difference of time to cool among the three conditions F 2,26 = 13.564, p = 0.001, ES = 0.401, 1-β = 0.950. Our results support multiple organizations that deem CWI as the only acceptable treatment, when compared to the cooling rates of The Polar Life Pod ® and ice sheets.
The comparison of cold-water immersion and cold air therapy on maximal cycling performance and recovery markers following strength exercises

PubMed Central

Hayter, Kane J.; Schumann, Moritz; Deakin, Glen B.

2016-01-01

This study examined the effects of cold-water immersion (CWI) and cold air therapy (CAT) on maximal cycling performance (i.e. anaerobic power) and markers of muscle damage following a strength training session. Twenty endurance-trained but strength-untrained male (n = 10) and female (n = 10) participants were randomised into either: CWI (15 min in 14 °C water to iliac crest) or CAT (15 min in 14 °C air) immediately following strength training (i.e. 3 sets of leg press, leg extensions and leg curls at 6 repetition maximum, respectively). Creatine kinase, muscle soreness and fatigue, isometric knee extensor and flexor torque and cycling anaerobic power were measured prior to, immediately after and at 24 (T24), 48 (T48) and 72 (T72) h post-strength exercises. No significant differences were found between treatments for any of the measured variables (p > 0.05). However, trends suggested recovery was greater in CWI than CAT for cycling anaerobic power at T24 (10% ± 2%, ES = 0.90), T48 (8% ± 2%, ES = 0.64) and T72 (8% ± 7%, ES = 0.76). The findings suggest the combination of hydrostatic pressure and cold temperature may be favourable for recovery from strength training rather than cold temperature alone. PMID:27069791
Real-time monitoring of the solution concentration variation during the crystallization process of protein-lysozyme by using digital holographic interferometry.

PubMed

Zhang, Yanyan; Zhao, Jianlin; Di, Jianglei; Jiang, Hongzhen; Wang, Qian; Wang, Jun; Guo, Yunzhu; Yin, Dachuan

2012-07-30

We report a real-time measurement method of the solution concentration variation during the growth of protein-lysozyme crystals based on digital holographic interferometry. A series of holograms containing the information of the solution concentration variation in the whole crystallization process is recorded by CCD. Based on the principle of double-exposure holographic interferometry and the relationship between the phase difference of the reconstructed object wave and the solution concentration, the solution concentration variation with time for arbitrary point in the solution can be obtained, and then the two-dimensional concentration distribution of the solution during crystallization process can also be figured out under the precondition which the refractive index is constant through the light propagation direction. The experimental results turns out that it is feasible to in situ, full-field and real-time monitor the crystal growth process by using this method.
Holodiagram: elliptic visualizing interferometry, relativity, and light-in-flight.

PubMed

Abramson, Nils H

2014-04-10

In holographic interferometry, there is usually a static distance separating the point of illumination and the point of observation. In Special Relativity, this separation is dynamic and is caused by the velocity of the observer. The corrections needed to compensate for these separations are similar in the two fields. We use the ellipsoids of the holodiagram for measurement and in a graphic way to explain and evaluate optical resolution, gated viewing, radar, holography, three-dimensional interferometry, Special Relativity, and light-in-flight recordings. Lorentz contraction together with time dilation is explained as the result of the eccentricity of the measuring ellipsoid, caused by its velocity. The extremely thin ellipsoid of the very first light appears as a beam aimed directly at the observer, which might explain the wave or ray duality of light and entanglement. Finally, we introduce the concept of ellipsoids of observation.
Digital Beamforming Interferometry

NASA Technical Reports Server (NTRS)

Rincon, Rafael F. (Inventor)

2016-01-01

Airborne or spaceborne Syntheic Aperture Radar (SAR) can be used in a variety of ways, and is often used to generate two dimensional images of a surface. SAR involves the use of radio waves to determine presence, properties, and features of extended areas. Specifically, radio waves are 10 transmitted in the presence of a ground surface. A portion of the radio wave's energy is reflected back to the radar system, which allows the radar system to detect and image the surface. Such radar systems may be used in science applications, military contexts, and other commercial applications.
Post-exercise cold water immersion does not alter high intensity interval training-induced exercise performance and Hsp72 responses, but enhances mitochondrial markers.

PubMed

Aguiar, Paula Fernandes; Magalhães, Sílvia Mourão; Fonseca, Ivana Alice Teixeira; da Costa Santos, Vanessa Batista; de Matos, Mariana Aguiar; Peixoto, Marco Fabrício Dias; Nakamura, Fábio Yuzo; Crandall, Craig; Araújo, Hygor Nunes; Silveira, Leonardo Reis; Rocha-Vieira, Etel; de Castro Magalhães, Flávio; Amorim, Fabiano Trigueiro

2016-09-01

This study aims to evaluate the effect of regular post-exercise cold water immersion (CWI) on intramuscular markers of cellular stress response and signaling molecules related to mitochondria biogenesis and exercise performance after 4 weeks of high intensity interval training (HIIT). Seventeen healthy subjects were allocated into two groups: control (CON, n = 9) or CWI (n = 8). Each HIIT session consisted of 8-12 cycling exercise stimuli (90-110 % of peak power) for 60 s followed by 75 s of active recovery three times per week, for 4 weeks (12 HIIT sessions). After each HIIT session, the CWI had their lower limbs immersed in cold water (10 °C) for 15 min and the CON recovered at room temperature. Exercise performance was evaluated before and after HIIT by a 15-km cycling time trial. Vastus lateralis biopsies were obtained pre and 72 h post training. Samples were analyzed for heat shock protein 72 kDa (Hsp72), adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) assessed by western blot. In addition, the mRNA expression of heat shock factor-1 (HSF-1), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), nuclear respiratory factor 1 and 2 (NRF1 and 2), mitochondrial transcription factor A (Tfam), calcium calmodulin-dependent protein kinase 2 (CaMK2) and enzymes citrate synthase (CS), carnitine palmitoyltransferase I (CPT1), and pyruvate dehydrogenase kinase (PDK4) were assessed by real-time PCR. Time to complete the 15-km cycling time trial was reduced with training (p < 0.001), but was not different between groups (p = 0.33). The Hsp72 (p = 0.01), p38 MAPK, and AMPK (p = 0.04) contents increased with training, but were not different between groups (p > 0.05). No differences were observed with training or condition for mRNA expression of PGC-1α (p = 0.31), CPT1 (p = 0.14), CS (p = 0.44), and NRF-2 (p = 0.82). However, HFS-1 (p = 0.007), PDK4 (p = 0.03), and Tfam (p = 0.03) mRNA were higher in CWI. NRF-1 decrease in both groups after training (p = 0.006). CaMK2 decreased with HIIT (p = 0.003) but it was not affected by CWI (p = 0.99). Cold water immersion does not alter HIIT-induced Hsp72, AMPK, p38 MAPK, and exercise performance but was able to increase some markers of cellular stress response and signaling molecules related to mitochondria biogenesis.
Reconstruction of a Three-Dimensional Transonic Rotor Flow Field from Holographical Interferogram Data.

DTIC Science & Technology

1985-03-01

interferometry and computer- R - spanwise coordinate, ft assisted tomography ( CAT ) are used to determine the transonic velocity field of a model rotor...and extracting fringe-order functions, the c data are transferred to a CAT code.- The CAT code Ui transmitted wave complex amplitude then calculates...the perturbation velocity in sev- eral planes above the blade surface. The values Ur reference wave complex amplitude from the holography- CAT method

Holographic evaluation of fatigue cracks by a compressive stress (HYSTERESIS) technique

NASA Technical Reports Server (NTRS)

Freska, S. A.; Rummel, W. D.

1974-01-01

Holographic interferometry compares unknown field of optical waves with known one. Differences are displayed as interference bands or fringes. Technique was evaluated on fatigue-cracked 2219-T87 aluminum-alloy panels. Small cracks were detected when specimen was incrementally unloaded.
Monitoring transmitted waves across a fault with a high potential for mining induced earthquakes -the Ezulwini gold mine in South Africa

NASA Astrophysics Data System (ADS)

Kawakata, H.; Yoshimitsu, N.; Nakatani, M.; Philipp, J.; Doi, I.; Naoi, M. M.; Ward, T.; Visser, V.; Morema, G.; Khambule, S.; Masakale, T.; Milev, A.; Durrheim, R. J.; Ribeiro, L.; Ward, M.; Ogasawara, H.

2011-12-01

It gives us important information about earthquake processes to monitor transmitted waves across a fault with a high potential for earthquake generation. In laboratory experiments, the decreases in elastic wave speed (e.g., Yoshimitsu et al., 2009) and attenuation parameter Q (Yoshimitsu and Kawakata, 2011) have been found prior to the faulting. In South African gold mines, we can specify a fault with a high potential for mining induced earthquakes of relatively large magnitude based on mining plans. In addition, the seismic line can be set at the depth of a few kilometers, so that the transmitted waves propagate through only hard rock. Hence, we started to monitor transmitted waves across a fault that has a high potential for an M˜2 earthquake at about 1 km deep in the Ezulwini gold mine. We installed a piezoelectric transmitter as a wave source about 20 m away from the fault in the hanging wall. Three accelerometers of 3-component were also installed in alignment with the transmitter; one is about 7 m away from the fault in the hanging wall, and the other two are about 7 m and 13 m away from the fault in the footwall, respectively. Then, the total length of our seismic line is ˜ 33 m long. The frequency response of accelerometers is within ±3 dB from 1 Hz to 10 kHz. For 10 minutes from midnight everyday, when there is no blasting, the elastic waves are transmitted every 0.05 seconds, and the received waves are recorded at 400 ksps on 14bit. Transmitted signals can be clearly recognized in stacked waveforms of all channels, although signal-to-noise ratios are high enough only in a frequency range from 3 kHz up to 10 kHz. The waveforms of three components are rotated so that one component (radial component) is parallel to the seismic line. Then, P waves are dominant in radial components for two sites in the footwall. On the other hand, at the nearest site in the hanging wall, near field term and/or intermediate term seem to be included. In addition to the transmission monitoring, ambient noise recording at 200 ksps for 50 minutes is carried out every day after the 10-minute transmission for the analysis of seismic noise interferometry. Further, from 1 AM to the next midnight everyday, earthquake trigger recording at 200 ksps is held for the analysis of coda-wave interferometry. These enable us not only to monitor the fault properties but to compare active imaging using transmission signals with passive imaging with seismic interferometry.
Residual Microstrain in Root Dentin after Canal Instrumentation Measured with Digital Moiré Interferometry.

PubMed

Lim, Helena; Li, Fang-Chi; Friedman, Shimon; Kishen, Anil

2016-09-01

Residual microstrain influences the resistance to crack propagation in a biomaterial. This study evaluated the residual microstrain and microdefects formed in dentin after canal instrumentation in teeth maintained in hydrated and nonhydrated environments. Canals of 18 extracted human premolars with single-root canals were instrumented in accordance with 3 groups: the ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) group: ProTaper Universal (S1, S2, F1, and F2) used in rotation, the WaveOne Primary (Dentsply Maillefer) group: the WaveOne (Primary) used in reciprocal motion, and the control group: hand files. Half the specimens (3/group) were maintained in deionized water (hydrated) and half in ambient relative humidity conditions (22°C, 55% RH) for 72 hours (nonhydrated). Customized high-sensitivity digital moiré interferometry was used to qualitatively evaluate pre- and postinstrumentation dentinal microstrain. Subsequently, specimens were examined for dentinal microdefects with micro-computed tomographic imaging and polarized light microscopy. Digital moiré interferometry showed only minor changes in postinstrumentation microstrain in hydrated dentin in all groups, suggestive of a stress relaxation behavior. Nonhydrated dentin in all groups showed localized concentration of postinstrumentation microstrain, which appeared higher in the WaveOne group than in the other groups. No dentinal microdefects were detected by micro-computed tomographic imaging and polarized light microscopy in hydrated and nonhydrated specimens in all groups. This study suggested that the biomechanical response of root dentin to instrumentation was influenced by hydration. Reciprocating, rotary, and hand instrumentation of well-hydrated roots did not cause an increase in residual microstrain or the formation of microdefects in root dentin. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
CMP reflection imaging via interferometry of distributed subsurface sources

NASA Astrophysics Data System (ADS)

Kim, D.; Brown, L. D.; Quiros, D. A.

2015-12-01

The theoretical foundations of recovering body wave energy via seismic interferometry are well established. However in practice, such recovery remains problematic. Here, synthetic seismograms computed for subsurface sources are used to evaluate the geometrical combinations of realistic ambient source and receiver distributions that result in useful recovery of virtual body waves. This study illustrates how surface receiver arrays that span a limited distribution suite of sources, can be processed to reproduce virtual shot gathers that result in CMP gathers which can be effectively stacked with traditional normal moveout corrections. To verify the feasibility of the approach in practice, seismic recordings of 50 aftershocks following the magnitude of 5.8 Virginia earthquake occurred in August, 2011 have been processed using seismic interferometry to produce seismic reflection images of the crustal structure above and beneath the aftershock cluster. Although monotonic noise proved to be problematic by significantly reducing the number of usable recordings, the edited dataset resulted in stacked seismic sections characterized by coherent reflections that resemble those seen on a nearby conventional reflection survey. In particular, "virtual" reflections at travel times of 3 to 4 seconds suggest reflector sat approximately 7 to 12 km depth that would seem to correspond to imbricate thrust structures formed during the Appalachian orogeny. The approach described here represents a promising new means of body wave imaging of 3D structure that can be applied to a wide array of geologic and energy problems. Unlike other imaging techniques using natural sources, this technique does not require precise source locations or times. It can thus exploit aftershocks too small for conventional analyses. This method can be applied to any type of microseismic cloud, whether tectonic, volcanic or man-made.
The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1

PubMed Central

2011-01-01

Background Polyhexamethylene biguanide (PHMB) is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating Acantamoeba infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of Saccharomyces cerevisiae, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound. In this study, we examined the factors involved in PHMB-cell interaction and the mechanisms that respond to the damage caused by this interaction. To achieve this, two research strategies were employed: the expression of some genes by RT-qPCR and the analysis of mutant strains. Results Cell Wall integrity (CWI) genes were induced in the PHMB-resistant Saccharomyces cerevisiae strain JP-1, although they are poorly expressed in the PHMB-sensitive Saccharomyces cerevisiae PE2 strain. This suggested that PHMB damages the glucan structure on the yeast cell wall. It was also confirmed by the observed sensitivity of the yeast deletion strains, Δslg1, Δrom2, Δmkk2, Δslt2, Δknr4, Δswi4 and Δswi4, which showed that the protein kinase C (PKC) regulatory mechanism is involved in the response and resistance to PHMB. The sensitivity of the Δhog1 mutant was also observed. Furthermore, the cytotoxicity assay and gene expression analysis showed that the part played by YAP1 and CTT1 genes in cell resistance to PHMB is unrelated to oxidative stress response. Thus, we suggested that Yap1p can play a role in cell wall maintenance by controlling the expression of the CWI genes. Conclusion The PHMB treatment of the yeast cells activates the PKC1/Slt2 (CWI) pathway. In addition, it is suggested that HOG1 and YAP1 can play a role in the regulation of CWI genes. PMID:21854579
Ergogenic effects of precooling with cold water immersion and ice ingestion: A meta-analysis.

PubMed

Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Abbiss, Chris R

2018-03-01

This review evaluated the effects of precooling via cold water immersion (CWI) and ingestion of ice slurry/slushy or crushed ice (ICE) on endurance performance measures (e.g. time-to-exhaustion and time trials) and psychophysiological parameters (core [T core ] and skin [T skin ] temperatures, whole body sweat [WBS] response, heart rate [HR], thermal sensation [TS], and perceived exertion [RPE]). Twenty-two studies were included in the meta-analysis based on the following criteria: (i) cooling was performed before exercise with ICE or CWI; (ii) exercise longer than 6 min was performed in ambient temperature ≥26°C; and (iii) crossover study design with a non-cooling passive control condition. CWI improved performance measures (weighted average effect size in Hedges' g [95% confidence interval] + 0.53 [0.28; 0.77]) and resulted in greater increase (ΔEX) in T skin (+4.15 [3.1; 5.21]) during exercise, while lower peak T core (-0.93 [-1.18; -0.67]), WBS (-0.74 [-1.18; -0.3]), and TS (-0.5 [-0.8; -0.19]) were observed without concomitant changes in ΔEX-T core (+0.19 [-0.22; 0.6]), peak T skin (-0.67 [-1.52; 0.18]), peak HR (-0.14 [-0.38; 0.11]), and RPE (-0.14 [-0.39; 0.12]). ICE had no clear effect on performance measures (+0.2 [-0.07; 0.46]) but resulted in greater ΔEX-T core (+1.02 [0.59; 1.45]) and ΔEX-T skin (+0.34 [0.02; 0.67]) without concomitant changes in peak T core (-0.1 [-0.48; 0.28]), peak T skin (+0.1 [-0.22; 0.41]), peak HR (+0.08 [-0.19; 0.35]), WBS (-0.12 [-0.42; 0.18]), TS (-0.2 [-0.49; 0.1]), and RPE (-0.01 [-0.33; 0.31]). From both ergogenic and thermoregulatory perspectives, CWI may be more effective than ICE as a precooling treatment prior to exercise in the heat.
Effectiveness of cold water immersion for treating exertional heat stress when immediate response is not possible.

PubMed

Flouris, A D; Friesen, B J; Carlson, M J; Casa, D J; Kenny, G P

2015-06-01

Immediate treatment with cold water immersion (CWI) is the gold standard for exertional heatstroke. In the field, however, treatment is often delayed due to delayed paramedic response and/or inaccurate diagnosis. We examined the effect of treatment (reduction of rectal temperature to 37.5 °C) delays of 5, 20, and 40 min on core cooling rates in eight exertionally heat-stressed (40.0 °C rectal temperature) individuals. We found that rectal temperature was elevated above baseline (P < 0.05) at the end of all delay periods (5 min: 40.08 ± 0.32; 20 min: 39.92 ± 0.40; 40 min: 39.57 ± 0.29 °C). Mean arterial pressure was reduced (P < 0.05) below baseline (92 ± 1.8 mm Hg) after all delay periods (5 min: 75 ± 2.6; 20 min: 74 ± 1.7; 40 min: 70 ± 2.1 mm Hg; P > 0.05). Rectal core cooling rates were similar among conditions (5 min: 0.20 ± 0.01; 20 min: 0.17 ± 0.02; 40 min: 0.17 ± 0.01 °C/min; P > 0.05). The rectal temperature afterdrop following CWI was similar across conditions (5 min: 35.95; 20 min: 35.61; 40 min: 35.87 °C; P > 0.05). We conclude that the effectiveness of 2 °C CWI as a treatment for exertional heat stress remains high even when applied with a delay of 40 min. Therefore, our results support that CWI is the most appropriate treatment for exertional heatstroke as it is capable of quickly reversing hyperthermia even when treatment is commenced with a significant delay. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Cold-water immersion after training sessions: Effects on fiber type-specific adaptations in muscle K+ transport proteins to sprint-interval training in men.

PubMed

Christiansen, Danny; Bishop, David John; Broatch, James R; Bangsbo, Jens; McKenna, Michael John; Murphy, Robyn M

2018-05-10

Effects of regular use of cold-water immersion (CWI) on fiber type-specific adaptations in muscle K + transport proteins to intense training, along with their relationship to changes in mRNA levels after the first training session, were investigated in humans. Nineteen recreationally-active men (24{plus minus}6 y, 79.5{plus minus}10.8 kg, 44.6{plus minus}5.8 mL∙kg -1 ∙min -1 ) completed six weeks of sprint-interval cycling either without (passive rest; CON) or with training sessions followed by CWI (15 min at 10{degree sign}C; COLD). Muscle biopsies were obtained before and after training to determine abundance of Na + ,K + -ATPase isoforms (α 1-3 , β 1-3 ) and FXYD1, and after recovery treatments (+0h and +3h) on the first day of training to measure mRNA content. Training increased (p<0.05) the abundance of α 1 and β 3 in both fiber types, β 1 in type-II fibers, and decreased FXYD1 in type-I fibers, whereas α 2 and α 3 abundance was not altered by training (p>0.05). CWI after each session did not influence responses to training (p>0.05). However, α 2 mRNA increased after the first session in COLD (+0h, p<0.05), but not in CON (p>0.05). In both conditions, α 1 and β 3 mRNA increased (+3h; p <0.05), β 2 mRNA decreased (+3h; p<0.05), whereas α 3 , β 1 , and FXYD1 mRNA remained unchanged (p>0.05) after the first session. In summary, Na + ,K + -ATPase isoforms are differently regulated in type I and II muscle fibers by sprint-interval training in humans, which for most isoforms do not associate with changes in mRNA levels after the first training session. CWI neither impairs nor improves protein adaptations to intense training of importance for muscle K + regulation.
Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise

PubMed Central

Christensen, Peter M.; Bangsbo, Jens

2016-01-01

Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance. PMID:27445857
Seismic interferometry by crosscorrelation and by multidimensional deconvolution: a systematic comparison

NASA Astrophysics Data System (ADS)

Wapenaar, Kees; van der Neut, Joost; Ruigrok, Elmer; Draganov, Deyan; Hunziker, Jürg; Slob, Evert; Thorbecke, Jan; Snieder, Roel

2011-06-01

Seismic interferometry, also known as Green's function retrieval by crosscorrelation, has a wide range of applications, ranging from surface-wave tomography using ambient noise, to creating virtual sources for improved reflection seismology. Despite its successful applications, the crosscorrelation approach also has its limitations. The main underlying assumptions are that the medium is lossless and that the wavefield is equipartitioned. These assumptions are in practice often violated: the medium of interest is often illuminated from one side only, the sources may be irregularly distributed, and losses may be significant. These limitations may partly be overcome by reformulating seismic interferometry as a multidimensional deconvolution (MDD) process. We present a systematic analysis of seismic interferometry by crosscorrelation and by MDD. We show that for the non-ideal situations mentioned above, the correlation function is proportional to a Green's function with a blurred source. The source blurring is quantified by a so-called interferometric point-spread function which, like the correlation function, can be derived from the observed data (i.e. without the need to know the sources and the medium). The source of the Green's function obtained by the correlation method can be deblurred by deconvolving the correlation function for the point-spread function. This is the essence of seismic interferometry by MDD. We illustrate the crosscorrelation and MDD methods for controlled-source and passive-data applications with numerical examples and discuss the advantages and limitations of both methods.
Measurement of Poisson's ratio of nonmetallic materials by laser holographic interferometry

NASA Astrophysics Data System (ADS)

Zhu, Jian T.

1991-12-01

By means of the off-axis collimated plane wave coherent light arrangement and a loading device by pure bending, Poisson's ratio values of CFRP (carbon fiber-reinforced plactics plates, lay-up 0 degree(s), 90 degree(s)), GFRP (glass fiber-reinforced plactics plates, radial direction) and PMMA (polymethyl methacrylate, x, y direction) have been measured. In virtue of this study, the ministry standard for the Ministry of Aeronautical Industry (Testing method for the measurement of Poisson's ratio of non-metallic by laser holographic interferometry) has been published. The measurement process is fast and simple. The measuring results are reliable and accurate.
Twisting Neutron Waves

NASA Astrophysics Data System (ADS)

Pushin, Dmitry

Most waves encountered in nature can be given a ``twist'', so that their phase winds around an axis parallel to the direction of wave propagation. Such waves are said to possess orbital angular momentum (OAM). For quantum particles such as photons, atoms, and electrons, this corresponds to the particle wavefunction having angular momentum of Lℏ along its propagation axis. Controlled generation and detection of OAM states of photons began in the 1990s, sparking considerable interest in applications of OAM in light and matter waves. OAM states of photons have found diverse applications such as broadband data multiplexing, massive quantum entanglement, optical trapping, microscopy, quantum state determination and teleportation, and interferometry. OAM states of electron beams have been used to rotate nanoparticles, determine the chirality of crystals and for magnetic microscopy. Here I discuss the first demonstration of OAM control of neutrons. Using neutron interferometry with a spatially incoherent input beam, we show the addition and conservation of quantum angular momenta, entanglement between quantum path and OAM degrees of freedom. Neutron-based quantum information science heretofore limited to spin, path, and energy degrees of freedom, now has access to another quantized variable, and OAM modalities of light, x-ray, and electron beams are extended to a massive, penetrating neutral particle. The methods of neutron phase imprinting demonstrated here expand the toolbox available for development of phase-sensitive techniques of neutron imaging. Financial support provided by the NSERC Create and Discovery programs, CERC and the NIST Quantum Information Program is acknowledged.
Producing data-based sensitivity kernels from convolution and correlation in exploration geophysics.

NASA Astrophysics Data System (ADS)

Chmiel, M. J.; Roux, P.; Herrmann, P.; Rondeleux, B.

2016-12-01

Many studies have shown that seismic interferometry can be used to estimate surface wave arrivals by correlation of seismic signals recorded at a pair of locations. In the case of ambient noise sources, the convergence towards the surface wave Green's functions is obtained with the criterion of equipartitioned energy. However, seismic acquisition with active, controlled sources gives more possibilities when it comes to interferometry. The use of controlled sources makes it possible to recover the surface wave Green's function between two points using either correlation or convolution. We investigate the convolutional and correlational approaches using land active-seismic data from exploration geophysics. The data were recorded on 10,710 vertical receivers using 51,808 sources (seismic vibrator trucks). The sources spacing is the same in both X and Y directions (30 m) which is known as a "carpet shooting". The receivers are placed in parallel lines with a spacing 150 m in the X direction and 30 m in the Y direction. Invoking spatial reciprocity between sources and receivers, correlation and convolution functions can thus be constructed between either pairs of receivers or pairs of sources. Benefiting from the dense acquisition, we extract sensitivity kernels from correlation and convolution measurements of the seismic data. These sensitivity kernels are subsequently used to produce phase-velocity dispersion curves between two points and to separate the higher mode from the fundamental mode for surface waves. Potential application to surface wave cancellation is also envisaged.
Proposal for quantum many-body simulation and torsional matter-wave interferometry with a levitated nanodiamond

NASA Astrophysics Data System (ADS)

Ma, Yue; Hoang, Thai M.; Gong, Ming; Li, Tongcang; Yin, Zhang-qi

2017-08-01

Hybrid spin-mechanical systems have great potential in sensing, macroscopic quantum mechanics, and quantum information science. In order to induce strong coupling between an electron spin and the center-of-mass motion of a mechanical oscillator, a large magnetic gradient usually is required, which is difficult to achieve. Here we show that strong coupling between the electron spin of a nitrogen-vacancy (NV) center and the torsional vibration of an optically levitated nanodiamond can be achieved in a uniform magnetic field. Thanks to the uniform magnetic field, multiple spins can strongly couple to the torsional vibration at the same time. We propose utilizing this coupling mechanism to realize the Lipkin-Meshkov-Glick (LMG) model by an ensemble of NV centers in a levitated nanodiamond. The quantum phase transition in the LMG model and finite number effects can be observed with this system. We also propose generating torsional superposition states and realizing torsional matter-wave interferometry with spin-torsional coupling.
The effect of different water immersion temperatures on post-exercise parasympathetic reactivation.

PubMed

de Oliveira Ottone, Vinícius; de Castro Magalhães, Flávio; de Paula, Fabrício; Avelar, Núbia Carelli Pereira; Aguiar, Paula Fernandes; da Matta Sampaio, Pâmela Fiche; Duarte, Tamiris Campos; Costa, Karine Beatriz; Araújo, Tatiane Líliam; Coimbra, Cândido Celso; Nakamura, Fábio Yuzo; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

2014-01-01

We evaluated the effect of different water immersion (WI) temperatures on post-exercise cardiac parasympathetic reactivation. Eight young, physically active men participated in four experimental conditions composed of resting (REST), exercise session (resistance and endurance exercises), post-exercise recovery strategies, including 15 min of WI at 15°C (CWI), 28°C (TWI), 38°C (HWI) or control (CTRL, seated at room temperature), followed by passive resting. The following indices were assessed before and during WI, 30 min post-WI and 4 hours post-exercise: mean R-R (mR-R), the natural logarithm (ln) of the square root of the mean of the sum of the squares of differences between adjacent normal R-R (ln rMSSD) and the ln of instantaneous beat-to-beat variability (ln SD1). The results showed that during WI mRR was reduced for CTRL, TWI and HWI versus REST, and ln rMSSD and ln SD1 were reduced for TWI and HWI versus REST. During post-WI, mRR, ln rMSSD and ln SD1 were reduced for HWI versus REST, and mRR values for CWI were higher versus CTRL. Four hours post exercise, mRR was reduced for HWI versus REST, although no difference was observed among conditions. We conclude that CWI accelerates, while HWI blunts post-exercise parasympathetic reactivation, but these recovery strategies are short-lasting and not evident 4 hours after the exercise session.
The Effect of Different Water Immersion Temperatures on Post-Exercise Parasympathetic Reactivation

PubMed Central

de Oliveira Ottone, Vinícius; de Castro Magalhães, Flávio; de Paula, Fabrício; Avelar, Núbia Carelli Pereira; Aguiar, Paula Fernandes; da Matta Sampaio, Pâmela Fiche; Duarte, Tamiris Campos; Costa, Karine Beatriz; Araújo, Tatiane Líliam; Coimbra, Cândido Celso; Nakamura, Fábio Yuzo; Amorim, Fabiano Trigueiro; Rocha-Vieira, Etel

2014-01-01

Purpose We evaluated the effect of different water immersion (WI) temperatures on post-exercise cardiac parasympathetic reactivation. Methods Eight young, physically active men participated in four experimental conditions composed of resting (REST), exercise session (resistance and endurance exercises), post-exercise recovery strategies, including 15 min of WI at 15°C (CWI), 28°C (TWI), 38°C (HWI) or control (CTRL, seated at room temperature), followed by passive resting. The following indices were assessed before and during WI, 30 min post-WI and 4 hours post-exercise: mean R-R (mR-R), the natural logarithm (ln) of the square root of the mean of the sum of the squares of differences between adjacent normal R–R (ln rMSSD) and the ln of instantaneous beat-to-beat variability (ln SD1). Results The results showed that during WI mRR was reduced for CTRL, TWI and HWI versus REST, and ln rMSSD and ln SD1 were reduced for TWI and HWI versus REST. During post-WI, mRR, ln rMSSD and ln SD1 were reduced for HWI versus REST, and mRR values for CWI were higher versus CTRL. Four hours post exercise, mRR was reduced for HWI versus REST, although no difference was observed among conditions. Conclusions We conclude that CWI accelerates, while HWI blunts post-exercise parasympathetic reactivation, but these recovery strategies are short-lasting and not evident 4 hours after the exercise session. PMID:25437181
A novel role of the ferric reductase Cfl1 in cell wall integrity, mitochondrial function, and invasion to host cells in Candida albicans.

PubMed

Yu, Qilin; Dong, Yijie; Xu, Ning; Qian, Kefan; Chen, Yulu; Zhang, Biao; Xing, Laijun; Li, Mingchun

2014-11-01

Candida albicans is an important opportunistic pathogen, causing both superficial mucosal infections and life-threatening systemic diseases. Iron acquisition is an important factor for pathogen-host interaction and also a significant element for the pathogenicity of this organism. Ferric reductases, which convert ferric iron into ferrous iron, are important components of the high-affinity iron uptake system. Sequence analyses have identified at least 17 putative ferric reductase genes in C. albicans genome. CFL1 was the first ferric reductase identified in C. albicans. However, little is known about its roles in C. albicans physiology and pathogenicity. In this study, we found that disruption of CFL1 led to hypersensitivity to chemical and physical cell wall stresses, activation of the cell wall integrity (CWI) pathway, abnormal cell wall composition, and enhanced secretion, indicating a defect in CWI in this mutant. Moreover, this mutant showed abnormal mitochondrial activity and morphology, suggesting a link between ferric reductases and mitochondrial function. In addition, this mutant displayed decreased ability of adhesion to both the polystyrene microplates and buccal epithelial cells and invasion of host epithelial cells. These findings revealed a novel role of C. albicans Cfl1 in maintenance of CWI, mitochondrial function, and interaction between this pathogen and the host. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
Explosively Driven Shock Induced Damage in OFHC Copper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koller, D. D.; Hixson, R. S.; Gray, G. T. III

OFHC Cu samples were subjected to shock loading using plane wave HE lenses to produce a uniaxial Taylor wave profile (shock followed by immediate release). Upon arrival of the shock wave at the free surface of the sample, the wave is reflected and propagates back into the sample as a release wave. It is the interaction of initial and reflected release waves that place the material in a localized state of tension which can ultimately result in damage and possibly complete failure of the material. The peak tensile stress and its location in the material are determined by the wavemore » shape. Damage evolution processes and localized behavior are discussed based on results from time-resolved free surface velocity (VISAR) interferometry and post shock metallurgical analysis of the soft recovered samples.« less
High lateral resolution exploration using surface waves from noise records

NASA Astrophysics Data System (ADS)

Chávez-García, Francisco José Yokoi, Toshiaki

2016-04-01

Determination of the shear-wave velocity structure at shallow depths is a constant necessity in engineering or environmental projects. Given the sensitivity of Rayleigh waves to shear-wave velocity, subsoil structure exploration using surface waves is frequently used. Methods such as the spectral analysis of surface waves (SASW) or multi-channel analysis of surface waves (MASW) determine phase velocity dispersion from surface waves generated by an active source recorded on a line of geophones. Using MASW, it is important that the receiver array be as long as possible to increase the precision at low frequencies. However, this implies that possible lateral variations are discarded. Hayashi and Suzuki (2004) proposed a different way of stacking shot gathers to increase lateral resolution. They combined strategies used in MASW with the common mid-point (CMP) summation currently used in reflection seismology. In their common mid-point with cross-correlation method (CMPCC), they cross-correlate traces sharing CMP locations before determining phase velocity dispersion. Another recent approach to subsoil structure exploration is based on seismic interferometry. It has been shown that cross-correlation of a diffuse field, such as seismic noise, allows the estimation of the Green's Function between two receivers. Thus, a virtual-source seismic section may be constructed from the cross-correlation of seismic noise records obtained in a line of receivers. In this paper, we use the seismic interferometry method to process seismic noise records obtained in seismic refraction lines of 24 geophones, and analyse the results using CMPCC to increase the lateral resolution of the results. Cross-correlation of the noise records allows reconstructing seismic sections with virtual sources at each receiver location. The Rayleigh wave component of the Green's Functions is obtained with a high signal-to-noise ratio. Using CMPCC analysis of the virtual-source seismic lines, we are able to identify lateral variations of phase velocity inside the seismic line, and increase the lateral resolution compared with results of conventional analysis.
High-resolution probing of inner core structure with seismic interferometry

NASA Astrophysics Data System (ADS)

Huang, Hsin-Hua; Lin, Fan-Chi; Tsai, Victor C.; Koper, Keith D.

2015-12-01

Increasing complexity of Earth's inner core has been revealed in recent decades as the global distribution of seismic stations has improved. The uneven distribution of earthquakes, however, still causes a biased geographical sampling of the inner core. Recent developments in seismic interferometry, which allow for the retrieval of core-sensitive body waves propagating between two receivers, can significantly improve ray path coverage of the inner core. In this study, we apply such earthquake coda interferometry to 1846 USArray stations deployed across the U.S. from 2004 through 2013. Clear inner core phases PKIKP2 and PKIIKP2 are observed across the entire array. Spatial analysis of the differential travel time residuals between the two phases reveals significant short-wavelength variation and implies the existence of strong structural variability in the deep Earth. A linear N-S trending anomaly across the middle of the U.S. may reflect an asymmetric quasi-hemispherical structure deep within the inner core with boundaries of 99°W and 88°E.

Reflection imaging of the Moon's interior using deep-moonquake seismic interferometry

NASA Astrophysics Data System (ADS)

Nishitsuji, Yohei; Rowe, C. A.; Wapenaar, Kees; Draganov, Deyan

2016-04-01

The internal structure of the Moon has been investigated over many years using a variety of seismic methods, such as travel time analysis, receiver functions, and tomography. Here we propose to apply body-wave seismic interferometry to deep moonquakes in order to retrieve zero-offset reflection responses (and thus images) beneath the Apollo stations on the nearside of the Moon from virtual sources colocated with the stations. This method is called deep-moonquake seismic interferometry (DMSI). Our results show a laterally coherent acoustic boundary around 50 km depth beneath all four Apollo stations. We interpret this boundary as the lunar seismic Moho. This depth agrees with Japan Aerospace Exploration Agency's (JAXA) SELenological and Engineering Explorer (SELENE) result and previous travel time analysis at the Apollo 12/14 sites. The deeper part of the image we obtain from DMSI shows laterally incoherent structures. Such lateral inhomogeneity we interpret as representing a zone characterized by strong scattering and constant apparent seismic velocity at our resolution scale (0.2-2.0 Hz).
Hydrogen Lines in Mira Stars Through Interferometry and Polarimetry

NASA Astrophysics Data System (ADS)

Fabas, N.; Chiavassa, A.; Millour, F.; Wittkowski, M.

2015-12-01

Balmer lines in emission are the most prominent features in Mira stars spectra and have a strong potential as a proxy to study the lower atmosphere's dynamics. In Fabas et al. ([1]), we accumulated spectropolarimetric observations of Balmer lines in emission. As the shock is propagating outwards, linear polarization rate increases and the angle of this polarization evolves. Assuming that linear polarization arises from anisotropic scattering, it has the potential of telling us about the geometric structure of the shock as it propagates and the study of such atmospheric structures can typically be performed with interferometry. In 2012, AMBER data on the Mira star omicron Ceti were collected in which the Brackett γ line is studied. The data show signatures in the interferometric observables around this line. Olivier Chesneau was in the jury evaluating the PhD thesis of N. Fabas and he was seduced by the idea to study these shock waves with interferometry and use polarimetry as a complementary study.
Experimental comparison of autodyne and heterodyne laser interferometry using an Nd:YVO₄ microchip laser.

PubMed

Jacquin, Olivier; Lacot, Eric; Glastre, Wilfried; Hugon, Olivier; Guillet de Chatellus, Hugues

2011-08-01

Using an Nd:YVO₄ microchip laser with a relaxation frequency in the megahertz range, we have experimentally compared a heterodyne interferometer based on a Michelson configuration with an autodyne interferometer based on the laser optical feedback imaging (LOFI) method regarding their signal-to-noise ratios. In the heterodyne configuration, the beating between the reference beam and the signal beam is realized outside the laser cavity, while in the autodyne configuration, the wave beating takes place inside the laser cavity, and the relaxation oscillations of the laser intensity then play an important part. For a given laser output power, object under investigation, and detection noise level, we have determined the amplification gain of the LOFI interferometer compared to the heterodyne interferometer. LOFI interferometry is demonstrated to show higher performance than heterodyne interferometry for a wide range of laser powers and detection levels of noise. The experimental results are in good agreement with the theoretical predictions.
Experimental determination of third-order elastic constants of diamond.

PubMed

Lang, J M; Gupta, Y M

2011-03-25

To determine the nonlinear elastic response of diamond, single crystals were shock compressed along the [100], [110], and [111] orientations to 120 GPa peak elastic stresses. Particle velocity histories and elastic wave velocities were measured by using laser interferometry. The measured elastic wave profiles were used, in combination with published acoustic measurements, to determine the complete set of third-order elastic constants. These constants represent the first experimental determination, and several differ significantly from those calculated by using theoretical models.
Summary of NASA Advanced Telescope and Observatory Capability Roadmap

NASA Technical Reports Server (NTRS)

Stahl, H. Phil; Feinberg, Lee

2006-01-01

The NASA Advanced Telescope and Observatory (ATO) Capability Roadmap addresses technologies necessary for NASA to enable future space telescopes and observatories operating in all electromagnetic bands, from x-rays to millimeter waves, and including gravity-waves. It lists capability priorities derived from current and developing Space Missions Directorate (SMD) strategic roadmaps. Technology topics include optics; wavefront sensing and control and interferometry; distributed and advanced spacecraft systems; cryogenic and thermal control systems; large precision structure for observatories; and the infrastructure essential to future space telescopes and observatories.
Summary of NASA Advanced Telescope and Observatory Capability Roadmap

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Feinberg, Lee

2007-01-01

The NASA Advanced Telescope and Observatory (ATO) Capability Roadmap addresses technologies necessary for NASA to enable future space telescopes and observatories operating in all electromagnetic bands, from x-rays to millimeter waves, and including gravity-waves. It lists capability priorities derived from current and developing Space Missions Directorate (SMD) strategic roadmaps. Technology topics include optics; wavefront sensing and control and interferometry; distributed and advanced spacecraft systems; cryogenic and thermal control systems; large precision structure for observatories; and the infrastructure essential to future space telescopes and observatories.
Multi-Axis Heterodyne Interferometry (MAHI)

NASA Astrophysics Data System (ADS)

Thorpe, James

The detection and measurement of gravitational waves represents humanity’s next, and final, opportunity to open an entirely new spectrum with which to view the universe. The first steps of this process will likely take place later this decade when the second-generation ground-based instruments such as Advanced LIGO approach design sensitivity. While these events will be historic, it will take a space-based detector to access the milliHertz gravitational wave frequency band, a band that is rich in both number and variety of sources. The Laser Interferometer Space Antenna (LISA) concept has been developed over the past two decades in the US and Europe to provide access to this band. The European Space Agency recently selected The Gravitational Universe as the science theme for the 3rd Large-class mission in the Cosmic Visions Programme, with the assumption that a LISA-like instrument would be implemented for launch in 2034. NASA has expressed interest in partnering on this effort and the US community has made its own judgment on the scientific potential of a space-based gravitational wave observatory through the selection of LISA as the 3rd flagship mission in the 2010 Decadal Survey. Much of the effort has been in retiring risk for the unique technologies that comprise a gravitational wave detector. A prime focus of this effort is LISA Pathfinder (LPF), a dedicated technology demonstrator mission led by ESA with contributions from NASA and several member states. LPF’s primary objective is to validate drag-free flight as an approach to realizing an inertial reference mass. Along the way, several important technologies will be demonstrated, including picometer-level heterodyne interferometry. However, there are several important differences between the interferometry design for LISA and that for LPF. These mostly result from the fact that LISA interferometry involves multiple lasers on separate spacecraft whereas LPF can use a single laser on a single spacecraft. We propose to develop a laboratory prototype of a LISA-like interferometric metrology system capable of simultaneously making picometer-level position and nanoradian-level attitude measurements of a free-flying target. In the LISA application, this prototype would represent the short-arm interferometer, measuring the displacement and relative attitude between the gravitational test mass and the spacecraft. This measurement is used both to drive the drag-free attitude and control system as well as to extract the gravitational wave science signal. In addition to the LISA application, such a system would have broader applications in future geodesy and formation-flying missions. The prototype free-flying metrology system will consist of the following subcomponents: an optical bench providing stable pathlengths, an optical target mounted on a precision actuator, a low-noise quadrant photoreceiver for generating differential wavefront signals, and a phase measurement system to measure the individual heterodyne signals and convert them into quantities such as position and angle. In addition to the moving target, the optical bench will include a pair of fixed targets to be used as references. Comparing the two reference interferometers will provide an estimate of the noise performance of the measurement system, while comparing a reference interferometer with the free-flying target will allow us to demonstrate measurement over a large dynamic range. In addition to making performance measurements, we will use this prototype system to explore a number of system-level issues related to free-flying interferometry including initial acquisition, beam-walk effects, and jitter couplings.
Holographic Interferometry of Oil Films and Droplets in Water with a Single-Beam Mirror-Type Scheme

DTIC Science & Technology

2011-03-01

A simple scheme of holographic interferometry is shown in Fig. 1. A beam from an He-Ne laser (wave- length 0.632/ym), expanded by a lens (F-5cm...1 March 2011 r\\i rii cos 9 - ra2cos9f fii cos 9 + n2cos9, 2nj cos 9 t\\2 = 1 + r\\2 nx cos 9 + n2cos9, (3) Here 9r is the transmission angle ...which is related to the incidence angle by cos 9, — .11 - I tii sin9\\2 n% It follows from Eq. (3) that, for n2 > «i (as in our case of the air
Deep frequency modulation interferometry.

PubMed

Gerberding, Oliver

2015-06-01

Laser interferometry with pm/Hz precision and multi-fringe dynamic range at low frequencies is a core technology to measure the motion of various objects (test masses) in space and ground based experiments for gravitational wave detection and geodesy. Even though available interferometer schemes are well understood, their construction remains complex, often involving, for example, the need to build quasi-monolithic optical benches with dozens of components. In recent years techniques have been investigated that aim to reduce this complexity by combining phase modulation techniques with sophisticated digital readout algorithms. This article presents a new scheme that uses strong laser frequency modulations in combination with the deep phase modulation readout algorithm to construct simpler and easily scalable interferometers.
Imaging issues for interferometry with CGH null correctors

NASA Astrophysics Data System (ADS)

Burge, James H.; Zhao, Chunyu; Zhou, Ping

2010-07-01

Aspheric surfaces, such as telescope mirrors, are commonly measured using interferometry with computer generated hologram (CGH) null correctors. The interferometers can be made with high precision and low noise, and CGHs can control wavefront errors to accuracy approaching 1 nm for difficult aspheric surfaces. However, such optical systems are typically poorly suited for high performance imaging. The aspheric surface must be viewed through a CGH that was intentionally designed to introduce many hundreds of waves of aberration. The imaging aberrations create difficulties for the measurements by coupling both geometric and diffraction effects into the measurement. These issues are explored here, and we show how the use of larger holograms can mitigate these effects.
New Experimental Setup for High-Pressure High-Temperature Gigahertz Ultrasonic Interferometry

NASA Astrophysics Data System (ADS)

Kantor, A. P.; Kantor, I. Y.; Dubrovinsky, L. S.; Jacobsen, S. D.

2005-12-01

The only direct information about Earth's interior comes from seismological observations of sound wave velocities. In order to create compositional and mineralogical model from seismological data knowledge of the elastic properties and crystal chemistry of minerals is necessary. Gigahertz ultrasonic interferometry (GUI) is a relatively new tool used to measure single-crystal compressional and shear-wave travel times, which are converted to sound velocities and elastic moduli for direct application to problems in geophysics. Although possibility of simultaneous high-pressure and high-temperature GUI measurements in diamond anvil cell was demonstrated before up to temperature of 250°C, in situ pressure measurements were not possible. We developed new experimental setup for simultaneous GUI and pressure determination using a ruby fluorescence gouge. A diamond anvil cell is equipped with a miniature internal resistive heater with thermocouple fixed at a very small distance from the sample chamber. DAC is mounted at the rotating stage with 5 degrees of freedom (XYZ and two tilting degrees), that can be fixed in three different positions: on top of a P-buffer rod for compressional wave velocities measurement, on top of S-buffer rod for shear wave velocities measurement and under the microscope, equipped with laser and portable high-resolution spectrometer for ruby fluorescence measurement. DAC under high temperature could be moved between these three positions, and independent pressure, temperature, S and P wave velocities measurements could be done simultaneously at each data point. In addition to single-crystal elasticity measurements, ability of GUI for elasticity measurements of liquids was demonstrated. Compressional wave velocities in liquid argon were measured at high pressures and temperatures, showing the ability of GUI for studies equation of state of a liquid.
Cell wall integrity signaling in plants: "To grow or not to grow that's the question".

PubMed

Voxeur, Aline; Höfte, Herman

2016-09-01

Plants, like yeast, have the ability to monitor alterations in the cell wall architecture that occur during normal growth or in changing environments and to trigger compensatory changes in the cell wall. We discuss how recent advances in our understanding of the cell wall architecture provide new insights into the role of cell wall integrity sensing in growth control. Next we review the properties of membrane receptor-like kinases that have roles in pH control, mechano-sensing and reactive oxygen species accumulation in growing cells and which may be the plant equivalents of the yeast cell wall integrity (CWI) sensors. Finally, we discuss recent findings showing an increasing role for CWI signaling in plant immunity and the adaptation to changes in the ionic environment of plant cells. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Analysis and suppression of passive noise in surface microseismic data

NASA Astrophysics Data System (ADS)

Forghani-Arani, Farnoush

Surface microseismic surveys are gaining popularity in monitoring the hydraulic fracturing process. The effectiveness of these surveys, however, is strongly dependent on the signal-to-noise ratio of the acquired data. Cultural and industrial noise generated during hydraulic fracturing operations usually dominate the data, thereby decreasing the effectiveness of using these data in identifying and locating microseismic events. Hence, noise suppression is a critical step in surface microseismic monitoring. In this thesis, I focus on two important aspects in using surface-recorded microseismic seismic data: first, I take advantage of the unwanted surface noise to understand the characteristics of these noise and extract information about the propagation medium from the noise; second, I propose effective techniques to suppress the surface noise while preserving the waveforms that contain information about the source of microseisms. Automated event identification on passive seismic data using only a few receivers is challenging especially when the record lengths span over long durations of time. I introduce an automatic event identification algorithm that is designed specifically for detecting events in passive data acquired with a small number of receivers. I demonstrate that the conventional STA/LTA (Short-term Average/Long-term Average) algorithm is not sufficiently effective in event detection in the common case of low signal-to-noise ratio. With a cross-correlation based method as an extension of the STA/LTA algorithm, even low signal-to-noise events (that were not detectable with conventional STA/LTA) were revealed. Surface microseismic data contains surface-waves (generated primarily from hydraulic fracturing activities) and body-waves in the form of microseismic events. It is challenging to analyze the surface-waves on the recorded data directly because of the randomness of their source and their unknown source signatures. I use seismic interferometry to extract the surface-wave arrivals. Interferometry is a powerful tool to extract waves (including body-wave and surface-waves) that propagate from any receiver in the array (called a pseudo source) to the other receivers across the array. Since most of the noise sources in surface microseismic data lie on the surface, seismic interferometry yields pseudo source gathers dominated by surface-wave energy. The dispersive characteristics of these surface-waves are important properties that can be used to extract information necessary for suppressing these waves. I demonstrate the application of interferometry to surface passive data recorded during the hydraulic fracturing operation of a tight gas reservoir and extract the dispersion properties of surface-waves corresponding to a pseudo-shot gather. Comparison of the dispersion characteristics of the surface waves from the pseudo-shot gather with that of an active shot-gather shows interesting similarities and differences. The dispersion character (e.g. velocity change with frequency) of the fundamental mode was observed to have the same behavior for both the active and passive data. However, for the higher mode surface-waves, the dispersion properties are extracted at different frequency ranges. Conventional noise suppression techniques in passive data are mostly stacking-based that rely on enforcing the amplitude of the signal by stacking the waveforms at the receivers and are unable to preserve the waveforms at the individual receivers necessary for estimating the microseismic source location and source mechanism. Here, I introduce a technique based on the tau - p transform, that effectively identifies and separates microseismic events from surface-wave noise in the tau -p domain. This technique is superior to conventional stacking-based noise suppression techniques, because it preserves the waveforms at individual receivers. Application of this methodology to microseismic events with isotropic and double-couple source mechanism, show substantial improvement in the signal-to-noise ratio. Imaging of the processed field data also show improved imaging of the hypocenter location of the microseismic source. In the case of double-couple source mechanism, I suggest two approaches for unifying the polarities at the receivers, a cross-correlation approach and a semblance-based prediction approach. The semblance-based approach is more effective at unifying the polarities, especially for low signal-to-noise ratio data.
Hand temperature responses to local cooling after a 10-day confinement to normobaric hypoxia with and without exercise.

PubMed

Keramidas, M E; Kölegård, R; Mekjavic, I B; Eiken, O

2015-10-01

The study examined the effects of a 10-day normobaric hypoxic confinement (FiO2: 0.14), with [hypoxic exercise training (HT); n = 8)] or without [hypoxic ambulatory (HA; n = 6)] exercise, on the hand temperature responses during and after local cold stress. Before and after the confinement, subjects immersed their right hand for 30 min in 8 °C water [cold water immersion (CWI)], followed by a 15-min spontaneous rewarming (RW), while breathing either room air (AIR), or a hypoxic gas mixture (HYPO). The hand temperature responses were monitored with thermocouples and infrared thermography. The confinement did not influence the hand temperature responses of the HA group during the AIR and HYPO CWI and the HYPO RW phases; but it impaired the AIR RW response (-1.3 °C; P = 0.05). After the confinement, the hand temperature responses were unaltered in the HT group throughout the AIR trial. However, the average hand temperature was increased during the HYPO CWI (+0.5 °C; P ≤ 0.05) and RW (+2.4 °C; P ≤ 0.001) phases. Accordingly, present findings suggest that prolonged exposure to normobaric hypoxia per se does not alter the hand temperature responses to local cooling; yet, it impairs the normoxic RW response. Conversely, the combined stimuli of continuous hypoxia and exercise enhance the finger cold-induced vasodilatation and hand RW responses, specifically, under hypoxic conditions. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Individual perception of recovery is related to subsequent sprint performance.

PubMed

Cook, Christian J; Beaven, Chris Martyn

2013-07-01

Training recovery is vital for adaptation and performance, and to avoid cumulative fatigue and symptoms associated with overtraining. The use of cold-water immersion (CWI) as a recovery strategy is common; however, the physiological and biochemical rationale behind its use remains unclear. This study aimed to assess the relationship between body temperature responses to water immersion and individual perception of recovery, with subsequent exercise performance. Twelve male rugby players participated in a 3-week cross-over trial where an intense 60 min conditioning session was followed immediately by 15 min of either 14°C CWI, 30°C warm-water immersion (WWI) or passive control (CON) recovery intervention. Postexercise body temperatures and subjective ratings of the recovery intervention were recorded and subsequently related to performance in a 5×40 m repeated sprint protocol undertaken 24 h later. CWI induced large reductions in core body temperature postimmersion (effect size (ES) range 1.05-3.21) and improved subsequent sprint performance compared to WWI (ES 1.04±0.84) and CON (ES 1.44±0.84). Both the degree of temperature decrease at 60 min postimmersion (r=0.6948; p=0.0121) and the subjective rating of the recovery intervention (r=0.5886; p=0.0441) were related to subsequent sprint performance. A very strong linear correlation was observed when these two factors were integrated (r=0.7743; p=0.0031). A combination of physiological and psychological indices provides an improved indication of subsequent performance and suggests an important role of individual perception in enhancing training recovery.
Effect of hydrotherapy on the signs and symptoms of delayed onset muscle soreness.

PubMed

Vaile, Joanna; Halson, Shona; Gill, Nicholas; Dawson, Brian

2008-03-01

This study independently examined the effects of three hydrotherapy interventions on the physiological and functional symptoms of delayed onset muscle soreness (DOMS). Strength trained males (n = 38) completed two experimental trials separated by 8 months in a randomised crossover design; one trial involved passive recovery (PAS, control), the other a specific hydrotherapy protocol for 72 h post-exercise; either: (1) cold water immersion (CWI: n = 12), (2) hot water immersion (HWI: n = 11) or (3) contrast water therapy (CWT: n = 15). For each trial, subjects performed a DOMS-inducing leg press protocol followed by PAS or one of the hydrotherapy interventions for 14 min. Weighted squat jump, isometric squat, perceived pain, thigh girths and blood variables were measured prior to, immediately after, and at 24, 48 and 72 h post-exercise. Squat jump performance and isometric force recovery were significantly enhanced (P < 0.05) at 24, 48 and 72 h post-exercise following CWT and at 48 and 72 h post-exercise following CWI when compared to PAS. Isometric force recovery was also greater (P < 0.05) at 24, 48, and 72 h post-exercise following HWI when compared to PAS. Perceived pain improved (P < 0.01) following CWT at 24, 48 and 72 h post-exercise. Overall, CWI and CWT were found to be effective in reducing the physiological and functional deficits associated with DOMS, including improved recovery of isometric force and dynamic power and a reduction in localised oedema. While HWI was effective in the recovery of isometric force, it was ineffective for recovery of all other markers compared to PAS.
LISA: Astrophysics Out to z Approximately 10 with Low-Frequency Gravitational Waves

NASA Technical Reports Server (NTRS)

Stebbins, Robin T.

2008-01-01

This viewgraph presentation reviews the Laser Interferometer Space Antenna (LISA). LISA os a joint ESA-NASA project to design, build and operate a space-based gravitational wave detector. The 5 million Kilometer long detector will consist of three spacecraft orbiting the Sun in a triangular formation. Space-Time strains induced by gravitational waves are detected by measuring changes in the separation of fiducial masses with laser interferometry. LISA is expected to detect signals from merging massive black holes, compact stellar objects spiraling into super massive black holes in galactic nuclei, thousands of close binaries of compact objects in the Milky way and possible backgrounds of cosmological origin.
Algorithms to eliminate the influence of non-uniform intensity distributions on wavefront reconstruction by quadri-wave lateral shearing interferometers

NASA Astrophysics Data System (ADS)

Chen, Xiao-jun; Dong, Li-zhi; Wang, Shuai; Yang, Ping; Xu, Bing

2017-11-01

In quadri-wave lateral shearing interferometry (QWLSI), when the intensity distribution of the incident light wave is non-uniform, part of the information of the intensity distribution will couple with the wavefront derivatives to cause wavefront reconstruction errors. In this paper, we propose two algorithms to reduce the influence of a non-uniform intensity distribution on wavefront reconstruction. Our simulation results demonstrate that the reconstructed amplitude distribution (RAD) algorithm can effectively reduce the influence of the intensity distribution on the wavefront reconstruction and that the collected amplitude distribution (CAD) algorithm can almost eliminate it.
Time-lapse changes in velocity and anisotropy in Japan's near surface after the 2011 Tohoku earthquake

NASA Astrophysics Data System (ADS)

Snieder, R.; Nakata, N.

2012-12-01

A strong-motion recording network, KiK-net, helps us to monitor temporal changes in the near surface in Japan. Each KiK-net station has two seismometers at the free surface and in a borehole a few hundred meters deep, and we can retrieve a traveling wave from the borehole receiver to the surface receiver by applying deconvolution based seismic interferometry. KiK-net recorded the 2011 Tohoku earthquake, which is one of the largest earthquakes in recent history, and seismicity around the time of the main shock. Using records of these seismicity and computing mean values of near-surface shear-wave velocities in the periods of January 1--March 10 and March 12--May 26 in 2011, we detect about a 5% reduction in the velocity after the Tohoku earthquake. The area of the velocity reduction is about 1,200 km wide, which is much wider than earlier studies reporting velocity reductions after larger earthquakes. The reduction partly recovers with time. We can also estimate the azimuthal anisotropy by detecting shear-wave splitting after applying seismic interferometry. Estimating mean values over the same periods as the velocity, we find the strength of anisotropy increased in most parts of northeastern Japan, but fast shear-wave polarization directions in the near surface did not significantly change. The changes in anisotropy and velocity are generally correlated, especially in the northeastern Honshu (the main island in Japan).
Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder

NASA Technical Reports Server (NTRS)

Guzman, Felipe

2010-01-01

The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1mHz-100mHz. This observation band is inaccessible to ground-based detectors due to the large ground motions of the Earth. Gravitational wave sources for LISA include galactic binaries, mergers of supermasive black-hole binaries, extreme-mass-ratio inspirals, and possibly from as yet unimagined sources. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset oF 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such us spacecraft control with micro-newton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. An introduction to laser interferometric gravitational wave detection, ground-based observatories, and a detailed description of the two missions together with an overview of current investigations conducted by the community will bc discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented

Estimation of canopy water interception of a near-tropical montane cloud forest in Taiwan

NASA Astrophysics Data System (ADS)

Apurva, B.; Huang, C. Y.; Zhang, J.

2017-12-01

Tropical and subtropical montane cloud forests are some of the rarest and least studied ecosystems. Due to the frequent immersion of fog water with high humidity, these zones are major water sources for lowland environments and habitats for many fauna and flora. Their dependence on cloud water leaves them highly susceptible to the effects of climate change. Studies have been conducted to quantify the characteristics of the low altitude clouds such as spatial dynamics, cloud top and base heights, occurrence frequency or immersion duration. In this study, we carried out a field measurement to estimate canopy water interception (CWI), which is directly utilized by the ecosystems. The study site was a 61 ha near-tropical hinoki cypress montane cloud forest plantation in northern Taiwan at 1705 m asl. Leaves of CHOB were clipped, air-dried and attached to trees at three different canopy depths from the top to the base of canopies along a high tower. The samples were weighed before and after the occurrence of a fog event. In addition, a cylinder shaped fog gauge was installed at the ground level next to the tower to assess amount of fog water penetrating the canopy layer. After afternoon fog events with the duration of 60 minutes, we found that there was an apparent trend of decline of CWI from top (mean ± standard deviation = 0.023 g ± 0.0015 g), middle (0.021 g ± 0.0015 g) to the bottom (0.013 g ± 0.0015 g) of the canopies. Since the study site is a coniferous evergreen forest plantation with a relatively homogenous surface through seasons, with the background knowledge of the average leaf area index of 4.4, we estimated that this 61 ha site harvested 28.2 Mg of CWI for a daily fog event. We also found that no clear evidence of CWI was observed below the canopies by referring to bi-weekly records from the cylinder shaded fog gauge. Therefore, we can assume that the majority fog water was intercepted by the hinoki cypress canopy layer. This study demonstrates that a substantial amount of fog water can be harvested by the montane cloud forest, and this horizontal precipitation is not negligible and should be taken into account for ecological research.
Community-wide promotion of physical activity in middle-aged and older Japanese: a 3-year evaluation of a cluster randomized trial.

PubMed

Kamada, Masamitsu; Kitayuguchi, Jun; Abe, Takafumi; Taguri, Masataka; Inoue, Shigeru; Ishikawa, Yoshiki; Harada, Kazuhiro; Lee, I-Min; Bauman, Adrian; Miyachi, Motohiko

2015-06-23

Promotion of physical activity (PA) is a key strategy to prevent non-communicable diseases. However, evidence on the effectiveness of community-wide interventions (CWIs) for promoting PA is limited. To evaluate the effectiveness of a 3-year CWI for promoting PA in middle-aged and older adults compared with usual public health services. This study is an extension to an original 1-year investigation study. Cluster randomized controlled trial with community as unit of randomization and individual as unit of analysis. 12 communities in Unnan, Japan were randomly allocated to the intervention (9) or the control (3). Additionally intervention communities were randomly allocated to aerobic activity promotion (Group A), flexibility and muscle-strengthening activities promotion (Group FM), or aerobic, flexibility, and muscle-strengthening activities promotion (Group AFM), each consisting of three communities. Randomly-sampled 4414 residents aged 40 to 79 years responded to the baseline survey (74%), and were analyzed in 2013-2014. A 3-year CWI based on social marketing, to promote PA from 2009 to 2012. The primary outcome was a change in regular aerobic, flexibility, and/or muscle-strengthening activities, defined by (1) engaging in 150 mins/week or more of walking, (2) engaging in daily flexibility activity, or (3) engaging 2 or more days/week in muscle-strengthening activities, evaluated at the individual level. Secondary outcomes were changes in specific types of PA and musculoskeletal pain. Outcomes were measured at baseline and at 1 and 3 years (2009, 2010, and 2012). The CWI did not significantly increase the proportion of adults who reached recommended levels of aerobic, flexibility, and/or muscle-strengthening activities (adjusted change difference = 1.6% [95% CI: -3.5, 6.6]). In the subgroup analysis, compared to the controls, adults doing flexibility activity daily significantly increased in Group FM (6.3% [95% CI: 1.9, 10.7]). In Group A and AFM for PA outcomes and in all groups for pain outcomes, there was no significant change compared to controls. The CWI did not achieve significant increase in the proportion of adults who reached recommended PA levels. However, it might be effective in promoting flexibility activity in middle-aged and older Japanese. UMIN-CTR UMIN000002683 .
Dispersion analysis of passive surface-wave noise generated during hydraulic-fracturing operations

USGS Publications Warehouse

Forghani-Arani, Farnoush; Willis, Mark; Snieder, Roel; Haines, Seth S.; Behura, Jyoti; Batzle, Mike; Davidson, Michael

2014-01-01

Surface-wave dispersion analysis is useful for estimating near-surface shear-wave velocity models, designing receiver arrays, and suppressing surface waves. Here, we analyze whether passive seismic noise generated during hydraulic-fracturing operations can be used to extract surface-wave dispersion characteristics. Applying seismic interferometry to noise measurements, we extract surface waves by cross-correlating several minutes of passive records; this approach is distinct from previous studies that used hours or days of passive records for cross-correlation. For comparison, we also perform dispersion analysis for an active-source array that has some receivers in common with the passive array. The active and passive data show good agreement in the dispersive character of the fundamental-mode surface-waves. For the higher mode surface waves, however, active and passive data resolve the dispersive properties at different frequency ranges. To demonstrate an application of dispersion analysis, we invert the observed surface-wave dispersion characteristics to determine the near-surface, one-dimensional shear-wave velocity.
Direct-to-digital holography reduction of reference hologram noise and fourier space smearing

DOEpatents

Voelkl, Edgar

2006-06-27

Systems and methods are described for reduction of reference hologram noise and reduction of Fourier space smearing, especially in the context of direct-to-digital holography (off-axis interferometry). A method of reducing reference hologram noise includes: recording a plurality of reference holograms; processing the plurality of reference holograms into a corresponding plurality of reference image waves; and transforming the corresponding plurality of reference image waves into a reduced noise reference image wave. A method of reducing smearing in Fourier space includes: recording a plurality of reference holograms; processing the plurality of reference holograms into a corresponding plurality of reference complex image waves; transforming the corresponding plurality of reference image waves into a reduced noise reference complex image wave; recording a hologram of an object; processing the hologram of the object into an object complex image wave; and dividing the complex image wave of the object by the reduced noise reference complex image wave to obtain a reduced smearing object complex image wave.
Matter-wave coherence limit owing to cosmic gravitational wave background

NASA Astrophysics Data System (ADS)

Steane, Andrew M.

2017-12-01

We study matter-wave interferometry in the presence of a stochastic background of gravitational waves. It is shown that if the background has a scale-invariant spectrum over a wide bandwidth (which is expected in a class of inflationary models of Big Bang cosmology), then separated-path interference cannot be observed for a lump of matter of size above a limit which is very insensitive to the strength and bandwidth of the fluctuations, unless the interferometer is servo-controlled or otherwise protected. For ordinary solid matter this limit is of order 1-10 mm. A servo-controlled or cross-correlated device would also exhibit limits to the observation of macroscopic interference, which we estimate for ordinary matter moving at speeds small compared to c.
Observation and modeling of source effects in coda wave interferometry at Pavlof volcano

USGS Publications Warehouse

Haney, M.M.; van, Wijik K.; Preston, L.A.; Aldridge, D.F.

2009-01-01

Sorting out source and path effects for seismic waves at volcanoes is critical for the proper interpretation of underlying volcanic processes. Source or path effects imply that seismic waves interact strongly with the volcanic subsurface, either through partial resonance in a conduit (Garces et al., 2000; Sturton and Neuberg, 2006) or by random scattering in the heterogeneous volcanic edifice (Wegler and Luhr, 2001). As a result, both source and path effects can cause seismic waves to repeatedly sample parts of the volcano, leading to enhanced sensitivity to small changes in material properties at those locations. The challenge for volcano seismologists is to detect and reliably interpret these subtle changes for the purpose of monitoring eruptions. ?? 2009 Society of Exploration Geophysicists.
Poisson's spot and Gouy phase

NASA Astrophysics Data System (ADS)

da Paz, I. G.; Soldati, Rodolfo; Cabral, L. A.; de Oliveira, J. G. G.; Sampaio, Marcos

2016-12-01

Recently there have been experimental results on Poisson spot matter-wave interferometry followed by theoretical models describing the relative importance of the wave and particle behaviors for the phenomenon. We propose an analytical theoretical model for Poisson's spot with matter waves based on the Babinet principle, in which we use the results for free propagation and single-slit diffraction. We take into account effects of loss of coherence and finite detection area using the propagator for a quantum particle interacting with an environment. We observe that the matter-wave Gouy phase plays a role in the existence of the central peak and thus corroborates the predominantly wavelike character of the Poisson's spot. Our model shows remarkable agreement with the experimental data for deuterium (D2) molecules.
Optical frequency-domain chromatic dispersion measurement method for higher-order modes in an optical fiber.

PubMed

Ahn, Tae-Jung; Jung, Yongmin; Oh, Kyunghwan; Kim, Dug Young

2005-12-12

We propose a new chromatic dispersion measurement method for the higher-order modes of an optical fiber using optical frequency modulated continuous-wave (FMCW) interferometry. An optical fiber which supports few excited modes was prepared for our experiments. Three different guiding modes of the fiber were identified by using far-field spatial beam profile measurements and confirmed with numerical mode analysis. By using the principle of a conventional FMWC interferometry with a tunable external cavity laser, we have demonstrated that the chromatic dispersion of a few-mode optical fiber can be obtained directly and quantitatively as well as qualitatively. We have also compared our measurement results with those of conventional modulation phase-shift method.
Ambient Noise Interferometry and Surface Wave Array Tomography: Promises and Problems

NASA Astrophysics Data System (ADS)

van der Hilst, R. D.; Yao, H.; de Hoop, M. V.; Campman, X.; Solna, K.

2008-12-01

In the late 1990ies most seismologists would have frowned at the possibility of doing high-resolution surface wave tomography with noise instead of with signal associated with ballistic source-receiver propagation. Some may still do, but surface wave tomography with Green's functions estimated through ambient noise interferometry ('sourceless tomography') has transformed from a curiosity into one of the (almost) standard tools for analysis of data from dense seismograph arrays. Indeed, spectacular applications of ambient noise surface wave tomography have recently been published. For example, application to data from arrays in SE Tibet revealed structures in the crust beneath the Tibetan plateau that could not be resolved by traditional tomography (Yao et al., GJI, 2006, 2008). While the approach is conceptually simple, in application the proverbial devil is in the detail. Full reconstruction of the Green's function requires that the wavefields used are diffusive and that ambient noise energy is evenly distributed in the spatial dimensions of interest. In the field, these conditions are not usually met, and (frequency dependent) non-uniformity of the noise sources may lead to incomplete reconstruction of the Green's function. Furthermore, ambient noise distributions can be time-dependent, and seasonal variations have been documented. Naive use of empirical Green's functions may produce (unknown) bias in the tomographic models. The degrading effect on EGFs of the directionality of noise distribution forms particular challenges for applications beyond isotropic surface wave inversions, such as inversions for (azimuthal) anisotropy and attempts to use higher modes (or body waves). Incomplete Green's function reconstruction can (probably) not be prevented, but it may be possible to reduce the problem and - at least - understand the degree of incomplete reconstruction and prevent it from degrading the tomographic model. We will present examples of Rayleigh wave inversions and discuss strategies to mitigate effects of incomplete Green's function reconstruction on tomographic images.
Infrasonic interferometry applied to synthetic and measured data

NASA Astrophysics Data System (ADS)

Fricke, Julius T.; Evers, Läslo G.; Ruigrok, Elmer; Wapenaar, Kees; Simons, Dick G.

2013-04-01

The estimation of the traveltime of infrasound through the atmosphere is interesting for several applications. For example, it could be used to determine temperature and wind of the atmosphere, since the traveltime depends on these atmospheric conditions (Haney, 2009). In this work the traveltime is estimated with infrasonic interferometry. In other words, we calculate the crosscorrelations of data of spatially distributed receivers. With this method the traveltime between two receivers is determined without the need for ground truth events. In a first step, we crosscorrelate synthetic data, which are generated by a raytracing model. This model takes into account the traveltime along the rays, the attenuation of the different atmospheric layers, the spreading of the rays and the influence of caustics. In these numerical experiments we show that it is possible to determine the traveltime through infrasonic interferometry. We present the results of infrasonic interferometry applied to measured data. Microbaroms are used in the crosscorrelation approach. Microbaroms are caused by ocean waves and are measured by the 'Large Aperture Infrasound Array' (LAIA). LAIA is being installed by the Royal Netherlands Meteorological Institute (KNMI) in the framework of the radio-astronomical 'Low Frequency Array' (LOFAR) initiative. LAIA consists currently of around twenty receivers (microbarometers) with an aperture of around 100 km, allowing for several inter-station distances. Here, we show the results of crosscorrelations as a function of receivers distance, to assess the signal coherency. This research is made possible by the support of the 'Netherlands Organization for Scientific Research' (NWO). Haney, M., 2009. Infrasonic ambient noise interferometry from correlations of microbaroms, Geophysical Research Letters, 36, L19808
Microwave interferometry technique for obtaining gas interface velocity measurements in an expansion tube facility

NASA Technical Reports Server (NTRS)

Laney, C. C., Jr.

1974-01-01

A microwave interferometer technique to determine the front interface velocity of a high enthalpy gas flow, is described. The system is designed to excite a standing wave in an expansion tube, and to measure the shift in this standing wave as it is moved by the test gas front. Data, in the form of a varying sinusoidal signal, is recorded on a high-speed drum camera-oscilloscope combination. Measurements of average and incremental velocities in excess of 6,000 meters per second were made.
Skin friction measurements by laser interferometry in swept shock wave/turbulent boundary-layer interactions

NASA Technical Reports Server (NTRS)

Kim, Kwang-Soo; Settles, Gary S.

1988-01-01

The laser interferometric skin friction meter was used to measure wall shear stress distributions in two interactions of fin-generated swept shock waves with turbulent boundary layers. The basic research configuration was an unswept sharp-leading-edge fin of variable angle mounted on a flatplate. The results indicate that such measurements are practical in high-speed interacting flows, and that a repeatability of + or - 6 percent or better is possible. Marked increases in wall shear were observed in both swept interactions tested.
Dual-wavelength phase-shifting digital holography selectively extracting wavelength information from wavelength-multiplexed holograms.

PubMed

Tahara, Tatsuki; Mori, Ryota; Kikunaga, Shuhei; Arai, Yasuhiko; Takaki, Yasuhiro

2015-06-15

Dual-wavelength phase-shifting digital holography that selectively extracts wavelength information from five wavelength-multiplexed holograms is presented. Specific phase shifts for respective wavelengths are introduced to remove the crosstalk components and extract only the object wave at the desired wavelength from the holograms. Object waves in multiple wavelengths are selectively extracted by utilizing 2π ambiguity and the subtraction procedures based on phase-shifting interferometry. Numerical results show the validity of the proposed technique. The proposed technique is also experimentally demonstrated.
Enhanced sensitivity of the LIGO gravitational wave detector by using squeezed states of light

NASA Astrophysics Data System (ADS)

Aasi, J.; Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Aguiar, O. D.; Ajith, P.; Allen, B.; Amador Ceron, E.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Ast, S.; Aston, S. M.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballmer, S.; Bao, Y.; Barayoga, J. C.; Barker, D.; Barr, B.; Barsotti, L.; Barton, M. A.; Bartos, I.; Bassiri, R.; Batch, J.; Bauchrowitz, J.; Behnke, B.; Bell, A. S.; Bell, C.; Bergmann, G.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bhadbhade, T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bond, C.; Bork, R.; Born, M.; Bose, S.; Bowers, J.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brinkmann, M.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Buckland, K.; Brückner, F.; Buchler, B. C.; Buonanno, A.; Burguet-Castell, J.; Byer, R. L.; Cadonati, L.; Camp, J. B.; Campsie, P.; Cannon, K.; Cao, J.; Capano, C. D.; Carbone, L.; Caride, S.; Castiglia, A. D.; Caudill, S.; Cavaglià, M.; Cepeda, C.; Chalermsongsak, T.; Chao, S.; Charlton, P.; Chen, X.; Chen, Y.; Cho, H.-S.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, C. T. Y.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J. A.; Constancio Junior, M.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cumming, A.; Cunningham, L.; Dahl, K.; Damjanic, M.; Danilishin, S. L.; Danzmann, K.; Daudert, B.; Daveloza, H.; Davies, G. S.; Daw, E. J.; Dayanga, T.; Deleeuw, E.; Denker, T.; Dent, T.; Dergachev, V.; Derosa, R.; Desalvo, R.; Dhurandhar, S.; di Palma, I.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Drasco, S.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edwards, M.; Effler, A.; Ehrens, P.; Eikenberry, S. S.; Engel, R.; Essick, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fairhurst, S.; Fang, Q.; Farr, B. F.; Farr, W.; Favata, M.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Finn, L. S.; Fisher, R. P.; Foley, S.; Forsi, E.; Fotopoulos, N.; Frede, M.; Frei, M. A.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fujimoto, M.-K.; Fulda, P. J.; Fyffe, M.; Gair, J.; Garcia, J.; Gehrels, N.; Gelencser, G.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Gil-Casanova, S.; Gill, C.; Gleason, J.; Goetz, E.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Graef, C.; Graff, P. B.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Griffo, C.; Grote, H.; Grover, K.; Grunewald, S.; Guido, C.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Haris, K.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Heefner, J.; Heintze, M. C.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Holtrop, M.; Hong, T.; Hooper, S.; Hough, J.; Howell, E. J.; Huang, V.; Huerta, E. A.; Hughey, B.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jang, Y. J.; Jesse, E.; Johnson, W. W.; Jones, D.; Jones, D. I.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasturi, R.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B. K.; Kim, C.; Kim, K.; Kim, N.; Kim, Y.-M.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kozak, D.; Kozameh, C.; Kremin, A.; Kringel, V.; Krishnan, B.; Kucharczyk, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuper, B. J.; Kurdyumov, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lantz, B.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Le Roux, A.; Leaci, P.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leong, J. R.; Levine, B.; Lhuillier, V.; Lin, A. C.; Litvine, V.; Liu, Y.; Liu, Z.; Lockerbie, N. A.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lormand, M.; Lough, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; MacArthur, J.; MacDonald, E.; Machenschalk, B.; Macinnis, M.; MacLeod, D. M.; Magaña-Sandoval, F.; Mageswaran, M.; Mailand, K.; Manca, G.; Mandel, I.; Mandic, V.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martin, I. W.; Martin, R. M.; Martinov, D.; Marx, J. N.; Mason, K.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; May, G.; Mazzolo, G.; McAuley, K.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Miller, J.; Mingarelli, C. M. F.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mokler, F.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Mori, T.; Morriss, S. R.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nanda Kumar, D.; Nash, T.; Nayak, R.; Necula, V.; Newton, G.; Nguyen, T.; Nishida, E.; Nishizawa, A.; Nitz, A.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; O'Dell, J.; O'Reilly, B.; O'Shaughnessy, R.; Ochsner, E.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Ou, J.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Pan, Y.; Pankow, C.; Papa, M. A.; Paris, H.; Parkinson, W.; Pedraza, M.; Penn, S.; Peralta, C.; Perreca, A.; Phelps, M.; Pickenpack, M.; Pierro, V.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Pöld, J.; Postiglione, F.; Poux, C.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prokhorov, L. G.; Puncken, O.; Quetschke, V.; Quintero, E.; Quitzow-James, R.; Raab, F. J.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Ramet, C.; Raymond, V.; Reed, C. M.; Reed, T.; Reid, S.; Reitze, D. H.; Riesen, R.; Riles, K.; Roberts, M.; Robertson, N. A.; Robinson, E. L.; Roddy, S.; Rodriguez, C.; Rodriguez, L.; Rodruck, M.; Rollins, J. G.; Romie, J. H.; Röver, C.; Rowan, S.; Rüdiger, A.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J.; Sankar, S.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schuette, D.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sergeev, A.; Shaddock, D. A.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G. R.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Stefszky, M.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stevens, D.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S. E.; Stroeer, A. S.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Szeifert, G.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Torres, C. V.; Torrie, C. I.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Vahlbruch, H.; Vallisneri, M.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vecchio, A.; Veitch, P. J.; Veitch, J.; Venkateswara, K.; Verma, S.; Vincent-Finley, R.; Vitale, S.; Vo, T.; Vorvick, C.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, M.; Wang, J.; Wang, X.; Wanner, A.; Ward, R. L.; Was, M.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; Wiseman, A. G.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R.; Williams, T.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkelmann, L.; Winkler, W.; Wipf, C.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yum, H.; Zanolin, M.; Zhang, F.; Zhang, L.; Zhao, C.; Zhu, H.; Zhu, X. J.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2013-08-01

Nearly a century after Einstein first predicted the existence of gravitational waves, a global network of Earth-based gravitational wave observatories is seeking to directly detect this faint radiation using precision laser interferometry. Photon shot noise, due to the quantum nature of light, imposes a fundamental limit on the attometre-level sensitivity of the kilometre-scale Michelson interferometers deployed for this task. Here, we inject squeezed states to improve the performance of one of the detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) beyond the quantum noise limit, most notably in the frequency region down to 150 Hz, critically important for several astrophysical sources, with no deterioration of performance observed at any frequency. With the injection of squeezed states, this LIGO detector demonstrated the best broadband sensitivity to gravitational waves ever achieved, with important implications for observing the gravitational-wave Universe with unprecedented sensitivity.
Seismic anisotropy in the vicinity of the Alpine fault, New Zealand, estimated by seismic interferometry

NASA Astrophysics Data System (ADS)

Takagi, R.; Okada, T.; Yoshida, K.; Townend, J.; Boese, C. M.; Baratin, L. M.; Chamberlain, C. J.; Savage, M. K.

2016-12-01

We estimate shear wave velocity anisotropy in shallow crust near the Alpine fault using seismic interferometry of borehole vertical arrays. We utilized four borehole observations: two sensors are deployed in two boreholes of the Deep Fault Drilling Project in the hanging wall side, and the other two sites are located in the footwall side. Surface sensors deployed just above each borehole are used to make vertical arrays. Crosscorrelating rotated horizontal seismograms observed by the borehole and surface sensors, we extracted polarized shear waves propagating from the bottom to the surface of each borehole. The extracted shear waves show polarization angle dependence of travel time, indicating shear wave anisotropy between the two sensors. In the hanging wall side, the estimated fast shear wave directions are parallel to the Alpine fault. Strong anisotropy of 20% is observed at the site within 100 m from the Alpine fault. The hanging wall consists of mylonite and schist characterized by fault parallel foliation. In addition, an acoustic borehole imaging reveals fractures parallel to the Alpine fault. The fault parallel anisotropy suggest structural anisotropy is predominant in the hanging wall, demonstrating consistency of geological and seismological observations. In the footwall side, on the other hand, the angle between the fast direction and the strike of the Alpine fault is 33-40 degrees. Since the footwall is composed of granitoid that may not have planar structure, stress induced anisotropy is possibly predominant. The direction of maximum horizontal stress (SHmax) estimated by focal mechanisms of regional earthquakes is 55 degrees of the Alpine fault. Possible interpretation of the difference between the fast direction and SHmax direction is depth rotation of stress field near the Alpine fault. Similar depth rotation of stress field is also observed in the SAFOD borehole at the San Andreas fault.
Seismic interferometry by multidimensional deconvolution as a means to compensate for anisotropic illumination

NASA Astrophysics Data System (ADS)

Wapenaar, K.; van der Neut, J.; Ruigrok, E.; Draganov, D.; Hunziker, J.; Slob, E.; Thorbecke, J.; Snieder, R.

2008-12-01

It is well-known that under specific conditions the crosscorrelation of wavefields observed at two receivers yields the impulse response between these receivers. This principle is known as 'Green's function retrieval' or 'seismic interferometry'. Recently it has been recognized that in many situations it can be advantageous to replace the correlation process by deconvolution. One of the advantages is that deconvolution compensates for the waveform emitted by the source; another advantage is that it is not necessary to assume that the medium is lossless. The approaches that have been developed to date employ a 1D deconvolution process. We propose a method for seismic interferometry by multidimensional deconvolution and show that under specific circumstances the method compensates for irregularities in the source distribution. This is an important difference with crosscorrelation methods, which rely on the condition that waves are equipartitioned. This condition is for example fulfilled when the sources are regularly distributed along a closed surface and the power spectra of the sources are identical. The proposed multidimensional deconvolution method compensates for anisotropic illumination, without requiring knowledge about the positions and the spectra of the sources.
The generation of higher-order Laguerre-Gauss optical beams for high-precision interferometry.

PubMed

Carbone, Ludovico; Fulda, Paul; Bond, Charlotte; Brueckner, Frank; Brown, Daniel; Wang, Mengyao; Lodhia, Deepali; Palmer, Rebecca; Freise, Andreas

2013-08-12

Thermal noise in high-reflectivity mirrors is a major impediment for several types of high-precision interferometric experiments that aim to reach the standard quantum limit or to cool mechanical systems to their quantum ground state. This is for example the case of future gravitational wave observatories, whose sensitivity to gravitational wave signals is expected to be limited in the most sensitive frequency band, by atomic vibration of their mirror masses. One promising approach being pursued to overcome this limitation is to employ higher-order Laguerre-Gauss (LG) optical beams in place of the conventionally used fundamental mode. Owing to their more homogeneous light intensity distribution these beams average more effectively over the thermally driven fluctuations of the mirror surface, which in turn reduces the uncertainty in the mirror position sensed by the laser light. We demonstrate a promising method to generate higher-order LG beams by shaping a fundamental Gaussian beam with the help of diffractive optical elements. We show that with conventional sensing and control techniques that are known for stabilizing fundamental laser beams, higher-order LG modes can be purified and stabilized just as well at a comparably high level. A set of diagnostic tools allows us to control and tailor the properties of generated LG beams. This enabled us to produce an LG beam with the highest purity reported to date. The demonstrated compatibility of higher-order LG modes with standard interferometry techniques and with the use of standard spherical optics makes them an ideal candidate for application in a future generation of high-precision interferometry.
Polarimetric Interferometry

DTIC Science & Technology

2007-02-01

frequency radio wave propagation through the ionosphere , where the earths magnetic field lines break this reciprocity symmetry and as a result the cross...polarisation terms are no longer equal. This observation can be used to calibrate the effects of Faraday rotation due to trans- ionospheric ...currently under investigation is polarimetric SAR tomography , which is the extension of conventional two-dimensional SAR imaging principle to three
Physiological and perceptual effects of precooling in wheelchair basketball athletes

PubMed Central

Pumpa, Kate; Knight, Emma; Miller, Joanna

2016-01-01

Objective To investigate the physiological and perceptual effects of three precooling strategies during pre-exercise rest in athletes with a spinal cord injury (SCI). Design Randomized, counterbalanced. Participants were precooled, then rested for 60 minutes (22.7 ± 0.2°C, 64.2 ± 2.6%RH). Setting National Wheelchair Basketball Training Centre, Australia. Participants Sixteen wheelchair basketball athletes with a SCI. Interventions Participants were precooled through; 1) 10 minutes of 15.8°C cold water immersion (CWI), 2) ingestion of 6.8 g/kg−1 of slushie (S) from sports drink; 3) ingestion of 6.8 g/kg−1 of slushie with application of iced towels to the legs, torso and back/arms (ST); or 4) ingestion of 6.8 g/kg−1 of room temperature (22.3°C) sports drink (CON). Outcome measures Core temperature (Tgi), skin temperature (Tsk), heart rate (HR), and thermal and gastrointestinal comfort. Results Following CWI, a significant reduction in Tgi was observed compared to CON, with a greatest reduction of 1.58°C occurring 40 minutes post-cooling (95% CI [1.07, 2.10]). A significant reduction in Tgi following ST compared to CON was also observed at 20 minutes (0.56°C; [0.03, 1.09]) and 30 minutes (0.56°C; [0.04, 1.09]) post-cooling. Additionally, a significant interaction between impairment level and time was observed for Tgi and HR, demonstrating athletes with a higher level of impairment experienced a greater reduction in HR and significant decrease in rate of decline in Tgi, compared to lesser impaired athletes. Conclusion CWI and ST can effectively lower body temperature in athletes with a SCI, and may assist in tolerating warm conditions. PMID:27192132
The MAPKK FgMkk1 of Fusarium graminearum regulates vegetative differentiation, multiple stress response, and virulence via the cell wall integrity and high-osmolarity glycerol signaling pathways.

PubMed

Yun, Yingzi; Liu, Zunyong; Zhang, Jingze; Shim, Won-Bo; Chen, Yun; Ma, Zhonghua

2014-07-01

Mitogen-activated protein (MAP) kinases play crucial roles in regulating fungal development, growth and pathogenicity, and in responses to the environment. In this study, we characterized a MAP kinase kinase FgMkk1 in Fusarium graminearum, the causal agent of wheat head blight. Phenotypic analyses of the FgMKK1 mutant (ΔFgMKK1) showed that FgMkk1 is involved in the regulation of hyphal growth, pigmentation, conidiation, deoxynivalenol biosynthesis and virulence of F. graminearum. ΔFgMKK1 also showed increased sensitivity to cell wall-damaging agents, and to osmotic and oxidative stresses, but exhibited decreased sensitivity to the fungicides iprodione and fludioxonil. In addition, the mutant revealed increased sensitivity to a biocontrol agent, Trichoderma atroviride. Western blot assays revealed that FgMkk1 positively regulates phosphorylation of the MAP kinases Mgv1 and FgOs-2, the key component in the cell wall integrity (CWI) and high-osmolarity glycerol (HOG) signalling pathway respectively. Yeast two-hybrid assay indicated that Mgv1 interacts with a transcription factor FgRlm1. The FgRLM1 mutant (ΔFgRLM1) showed increased sensitivity to cell wall-damaging agents and exhibited decreased virulence. Taken together, our data indicated that FgMkk1 is an upstream component of Mgv1, and regulates vegetative differentiation, multiple stress response and virulence via the CWI and HOG signalling pathways. FgRlm1 may be a downstream component of Mgv1 in the CWI pathway in F. graminearum. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Holographic nondestructive tests performed on composite samples of ceramic-epoxy-fiberglass sandwich structure

NASA Technical Reports Server (NTRS)

Kurtz, R. L.; Liu, H. K.

1974-01-01

When a hologram storing more than one wave is illuminated with coherent light, the reconstructed wave fronts interfere with each other or with any other phase-related wave front derived from the illuminating source. This multiple wave front comparison is called holographic interferometry, and its application is called holographic nondestructive testing (HNDT). The theoretical aspects of HNDT techniques and the sensitivity of the holographic system to the geometrical placement of the optical components are briefly discussed. A unique HNDT system which is mobile and possesses variable sensitivity to stress amplitude is discribed, the experimental evidence of the application of this system to the testing of the hidden debonds in a ceramic-epoxy-fiberglass structure used for sample testing of the radome of the Pershing missile system is presented.
Bose-Einstein condensation in microgravity.

PubMed

van Zoest, T; Gaaloul, N; Singh, Y; Ahlers, H; Herr, W; Seidel, S T; Ertmer, W; Rasel, E; Eckart, M; Kajari, E; Arnold, S; Nandi, G; Schleich, W P; Walser, R; Vogel, A; Sengstock, K; Bongs, K; Lewoczko-Adamczyk, W; Schiemangk, M; Schuldt, T; Peters, A; Könemann, T; Müntinga, H; Lämmerzahl, C; Dittus, H; Steinmetz, T; Hänsch, T W; Reichel, J

2010-06-18

Albert Einstein's insight that it is impossible to distinguish a local experiment in a "freely falling elevator" from one in free space led to the development of the theory of general relativity. The wave nature of matter manifests itself in a striking way in Bose-Einstein condensates, where millions of atoms lose their identity and can be described by a single macroscopic wave function. We combine these two topics and report the preparation and observation of a Bose-Einstein condensate during free fall in a 146-meter-tall evacuated drop tower. During the expansion over 1 second, the atoms form a giant coherent matter wave that is delocalized on a millimeter scale, which represents a promising source for matter-wave interferometry to test the universality of free fall with quantum matter.
Information Content in Radio Waves: Student Investigations in Radio Science

NASA Astrophysics Data System (ADS)

Jacobs, K.; Scaduto, T.

2013-12-01

We describe an inquiry-based instructional unit on information content in radio waves, created in the summer of 2013 as part of a MIT Haystack Observatory (Westford, MA) NSF Research Experiences for Teachers (RET) program. This topic is current and highly relevant, addressing science and technical aspects from radio astronomy, geodesy, and atmospheric research areas as well as Next Generation Science Standards (NGSS). Projects and activities range from simple classroom demonstrations and group investigations, to long term research projects incorporating data acquisition from both student-built instrumentation as well as online databases. Each of the core lessons is applied to one of the primary research centers at Haystack through an inquiry project that builds on previously developed units through the MIT Haystack RET program. In radio astronomy, students investigate the application of a simple and inexpensive software defined radio chip (RTL-SDR) for use in systems implementing a small and very small radio telescope (SRT and VSRT). Both of these systems allow students to explore fundamental principles of radio waves and interferometry as applied to radio astronomy. In ionospheric research, students track solar storms from the initial coronal mass ejection (using Solar Dynamics Observatory images) to the resulting variability in total electron density concentrations using data from the community standard Madrigal distributed database system maintained by MIT Haystack. Finally, students get to explore very long-baseline interferometry as it is used in geodetic studies by measuring crustal plate displacements over time. Alignment to NextGen standards is provided for each lesson and activity with emphasis on HS-PS4 'Waves and Their Applications in Technologies for Information Transfer'.
Recovery practices in Division 1 collegiate athletes in North America.

PubMed

Murray, Andrew; Fullagar, Hugh; Turner, Anthony P; Sproule, John

2018-05-08

Establish current practice and attitudes towards recovery in a group of Division-1 Collegiate athletes from North America. A 16-item questionnaire was administered via custom software in an electronic format. 152 student athletes from a Division-1 Collegiate school across 3 sports (Basketball, American Football, Soccer). The approaches and attitudes to recovery in both training and competition. Sleep, cold water immersion (CWI) and nutrition were perceived to be the most effective modalities (88, 84 and 80% of the sample believed them to have a benefit respectively). Over half the sample did not believe in using compression for recovery. With regard to actual usage, CWI was the most used recovery modality and matched by athletes believing in, and using, the approach (65%). Only 24% of student athletes believed in, and used, sleep as a recovery modality despite it being rated and perceived as the most effective. Collectively, there is a discrepancy between perception and use of recovery modalities in Collegiate athletes. Copyright © 2018 Elsevier Ltd. All rights reserved.
The transcriptional control machinery as well as the cell wall integrity and its regulation are involved in the detoxification of the organic solvent dimethyl sulfoxide in Saccharomyces cerevisiae.

PubMed

Zhang, Lilin; Liu, Ningning; Ma, Xiao; Jiang, Linghuo

2013-03-01

In the present study, we have identified 339 dimethyl sulfoxide (DMSO)-sensitive and nine DMSO-tolerant gene mutations in Saccharomyces cerevisiae through a functional genomics approach. Twelve of these identified DMSO-sensitive mutations are of genes involved in the general control of gene expression mediated by the SWR1 complex and the RNA polymerase II mediator complex, whereas 71 of them are of genes involved in the protein trafficking and vacuolar sorting processes. In addition, twelve of these DMSO-sensitive mutations are of genes involved in the cell wall integrity (CWI) and its regulation. DMSO-tolerant mutations are of genes mainly involved in the metabolism and the gene expression control. Therefore, the transcriptional control machinery, the CWI and its regulation as well as the protein trafficking and sorting process play critical roles in the DMSO detoxification in yeast cells. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Imaging acoustic vibrations in an ear model using spectrally encoded interferometry

NASA Astrophysics Data System (ADS)

Grechin, Sveta; Yelin, Dvir

2018-01-01

Imaging vibrational patterns of the tympanic membrane would allow an accurate measurement of its mechanical properties and provide early diagnosis of various hearing disorders. Various optical technologies have been suggested to address this challenge and demonstrated in vitro using point scanning and full-field interferometry. Spectrally encoded imaging has been previously demonstrated capable of imaging tissue acoustic vibrations with high spatial resolution, including two-dimensional phase and amplitude mapping. In this work, we demonstrate a compact optical apparatus for imaging acoustic vibrations that could be incorporated into a commercially available digital otoscope. By transmitting harmonic sound waves through the otoscope insufflation port and analyzing the spectral interferograms using custom-built software, we demonstrate high-resolution vibration imaging of a circular rubber membrane within an ear model.
Surface based detection schemes for molecular interferometry experiments - implications and possible applications

NASA Astrophysics Data System (ADS)

Juffmann, Thomas; Milic, Adriana; Muellneritsch, Michael; Arndt, Markus

2011-03-01

Surface based detection schemes for molecular interferometry experiments might be crucial in the search for the quantum properties of larger and larger objects since they provide single particle sensitivity. Here we report on molecular interferograms of different biomolecules imaged using fluorescence microscopy. Being able to watch the build-up of an interferogram live and in situ reveals the matter-wave behavior of these complex molecules in an unprecedented way. We examine several problems encountered due to van-der-Waals forces between the molecules and the diffraction grating and discuss possible ways to circumvent these. Especially the advent of ultra-thin (1-100 atomic layers) diffraction masks might path the way towards molecular holography. We also discuss other possible applications such as coherent molecular microscopy.
Seismic Interferometry of Cultural Noise: Body Waves Extracted from Auto and Train Traffic

NASA Astrophysics Data System (ADS)

Quiros, D. A.; Brown, L. D.; Kim, D.

2014-12-01

Here we report results of two experiments designed to evaluate the utility of anthropogenic noise as a source for generating body waves via interferometry. In particular we address the suggestion that traffic noise might prove effective at producing P and S waves at frequencies and amplitudes appropriate for crustal scale refraction and reflection imaging. The first experiment recorded routine traffic for about 10 days along a straight stretch of a rural highway between the towns of Elmira and Ithaca in upstate New York. The array was deployed along the highway using two different spacings: an inner segment with Δx ~ 25 m, bracketed between flanking segments with Δx ~ 100 m. In addition to strong surface waves, direct and reflected P waves were clearly apparent on most of the virtual shot gathers. These P-waves match the velocities of P-waves recorded from a conventional, small scale refraction survey carried out at the same site with a shotgun source and an engineering seismograph. The second experiment was located in the Rio Grande rift near Belen New Mexico, where relatively isolated train traffic was recorded for about 6 days parallel to a busy section of the BNRF railway that bisects New Mexico. Interferometric processing of the data produced virtual shot gathers with strong surface waves, as expected, but also linear arrivals that exhibit apparent velocities similar to those reported for the shallow Tertiary-Quaternary alluvium based on the original COCORP vibroseis surveys nearby. However the virtual shot gathers derived from the train sources are more complex that those obtained from the auto noise, which we suspect is due to the extended length of the train source relative to the spread length. Both experiments confirm that cultural noise can be used for subsurface imaging, though the cost effectiveness of this approach depends, among other factors, upon the total length of recording time needed to probe to depths of interest. They are both sources that clearly lend themselves to exploitation by the new generation of large N array technologies.
Hybrid shearing and phase-shifting point diffraction interferometer

DOEpatents

Goldberg, Kenneth Alan; Naulleau, Patrick P.

2003-06-03

A new interferometry configuration combines the strengths of two existing interferometry methods, improving the quality and extending the dynamic range of both. On the same patterned mask, placed near the image-plane of an optical system under test, patterns for phase-shifting point diffraction interferometry and lateral shearing interferometry coexist. The former giving verifiable high accuracy for the measurement of nearly diffraction-limited optical systems. The latter enabling the measurement of optical systems with more than one wave of aberration in the system wavefront. The interferometry configuration is a hybrid shearing and point diffraction interferometer system for testing an optical element that is positioned along an optical path including: a source of electromagnetic energy in the optical path; a first beam splitter that is secured to a device that includes means for maneuvering the first beam splitter in a first position wherein the first beam splitter is in the optical path dividing light from the source into a reference beam and a test beam and in a second position wherein the first beam splitter is outside the optical path: a hybrid mask which includes a first section that defines a test window and at least one reference pinhole and a second section that defines a second beam splitter wherein the hybrid mask is secured to a device that includes means for maneuvering either the first section or the second section into the optical path positioned in an image plane that is created by the optical element, with the proviso that the first section of the hybrid mask is positioned in the optical path when first beam splitter is positioned in the optical path; and a detector positioned after the hybrid mask along the optical path.
Cold-Water Immersion for Hyperthermic Humans Wearing American Football Uniforms.

PubMed

Miller, Kevin C; Swartz, Erik E; Long, Blaine C

2015-08-01

Current treatment recommendations for American football players with exertional heatstroke are to remove clothing and equipment and immerse the body in cold water. It is unknown if wearing a full American football uniform during cold-water immersion (CWI) impairs rectal temperature (Trec) cooling or exacerbates hypothermic afterdrop. To determine the time to cool Trec from 39.5°C to 38.0°C while participants wore a full American football uniform or control uniform during CWI and to determine the uniform's effect on Trec recovery postimmersion. Crossover study. Laboratory. A total of 18 hydrated, physically active, unacclimated men (age = 22 ± 3 years, height = 178.8 ± 6.8 cm, mass = 82.3 ± 12.6 kg, body fat = 13% ± 4%, body surface area = 2.0 ± 0.2 m(2)). Participants wore the control uniform (undergarments, shorts, crew socks, tennis shoes) or full uniform (control plus T-shirt; tennis shoes; jersey; game pants; padding over knees, thighs, and tailbone; helmet; and shoulder pads). They exercised (temperature approximately 40°C, relative humidity approximately 35%) until Trec reached 39.5°C. They removed their T-shirts and shoes and were then immersed in water (approximately 10°C) while wearing each uniform configuration; time to cool Trec to 38.0°C (in minutes) was recorded. We measured Trec (°C) every 5 minutes for 30 minutes after immersion. Time to cool from 39.5°C to 38.0°C and Trec. The Trec cooled to 38.0°C in 6.19 ± 2.02 minutes in full uniform and 8.49 ± 4.78 minutes in control uniform (t17 = -2.1, P = .03; effect size = 0.48) corresponding to cooling rates of 0.28°C·min(-1) ± 0.12°C·min(-1) in full uniform and 0.23°C·min(-1) ± 0.11°C·min(-1) in control uniform (t17 = 1.6, P = .07, effect size = 0.44). The Trec postimmersion recovery did not differ between conditions over time (F1,17 = 0.6, P = .59). We speculate that higher skin temperatures before CWI, less shivering, and greater conductive cooling explained the faster cooling in full uniform. Cooling rates were considered ideal when the full uniform was worn during CWI, and wearing the full uniform did not cause a greater postimmersion hypothermic afterdrop. Clinicians may immerse football athletes with hyperthermia wearing a full uniform without concern for negatively affecting body-core cooling.
Non-contact fluid characterization in containers using ultrasonic waves

DOEpatents

Sinha, Dipen N [Los Alamos, NM

2012-05-15

Apparatus and method for non-contact (stand-off) ultrasonic determination of certain characteristics of fluids in containers or pipes are described. A combination of swept frequency acoustic interferometry (SFAI), wide-bandwidth, air-coupled acoustic transducers, narrowband frequency data acquisition, and data conversion from the frequency domain to the time domain, if required, permits meaningful information to be extracted from such fluids.
Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

NASA Astrophysics Data System (ADS)

Spargo, Andrew J.; Reid, Iain M.; MacKinnon, Andrew D.; Holdsworth, David A.

2017-06-01

Mesospheric gravity wave (GW) momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E) experiments (conducted from July 1997 to June 1998) are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions). The received beams were analysed with hybrid Doppler interferometry (HDI) (Holdsworth and Reid, 1998), principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997), later re-introduced by Hocking (2005) and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010) of the accuracy of the meteor radar technique.
Organ of Corti Micromechanics with Local Electrical Stimulation

NASA Astrophysics Data System (ADS)

Chen, Fangyi; Zheng, Jiefu; Choudhury, Niloy; Jaques, Steve; Nuttall, Alfred L.

2009-02-01

Optical low coherence interferometry is able to both image and measure the vibration of the cellular and non-cellular structures of the organ of Corti in vivo. In this study we applied an electric current to the basal turn from a pair of electrodes, one in scala tympani and the other in scala vestibuli, at the location corresponding to ~17 kHz when interferometry measurements were made. The coherence gate of the interferometer was positioned 1) at the basilar membrane (BM) near the radial location of the outer hair cells (OHCs) (approximately 1/2 the width of the BM) and 2) at the reticular lamina (RL) where the OHCs are located. We confirmed that electrical stimulation with a frequency sweep (12 kHz -25 kHz) caused a mechanical BM displacement with a peak and a traveling wave-like phase delay as we reported previously using laser Doppler velocimetry and reflective beads on the BM. Reflective beads were not used in the current study. The vibration of the RL had little or no phase delay that would characterize a traveling wave. These data suggest a very high compliance system for the electrically activated cellular structure of the organ.
Spectral Interferometry with Electron Microscopes

PubMed Central

Talebi, Nahid

2016-01-01

Interference patterns are not only a defining characteristic of waves, but also have several applications; characterization of coherent processes and holography. Spatial holography with electron waves, has paved the way towards space-resolved characterization of magnetic domains and electrostatic potentials with angstrom spatial resolution. Another impetus in electron microscopy has been introduced by ultrafast electron microscopy which uses pulses of sub-picosecond durations for probing a laser induced excitation of the sample. However, attosecond temporal resolution has not yet been reported, merely due to the statistical distribution of arrival times of electrons at the sample, with respect to the laser time reference. This is however, the very time resolution which will be needed for performing time-frequency analysis. These difficulties are addressed here by proposing a new methodology to improve the synchronization between electron and optical excitations through introducing an efficient electron-driven photon source. We use focused transition radiation of the electron as a pump for the sample. Due to the nature of transition radiation, the process is coherent. This technique allows us to perform spectral interferometry with electron microscopes, with applications in retrieving the phase of electron-induced polarizations and reconstructing dynamics of the induced vector potential. PMID:27649932
Atom Interferometry with the Sr Optical Clock Transition.

PubMed

Hu, Liang; Poli, Nicola; Salvi, Leonardo; Tino, Guglielmo M

2017-12-29

We report on the realization of a matter-wave interferometer based on single-photon interaction on the ultranarrow optical clock transition of strontium atoms. We experimentally demonstrate its operation as a gravimeter and as a gravity gradiometer. No reduction of interferometric contrast was observed for a total interferometer time up to ∼10 ms, limited by geometric constraints of the apparatus. Single-photon interferometers represent a new class of high-precision sensors that could be used for the detection of gravitational waves in so far unexplored frequency ranges and to enlighten the boundary between quantum mechanics and general relativity.
NASA capabilities roadmap: advanced telescopes and observatories

NASA Technical Reports Server (NTRS)

Feinberg, Lee D.

2005-01-01

The NASA Advanced Telescopes and Observatories (ATO) Capability Roadmap addresses technologies necessary for NASA to enable future space telescopes and observatories collecting all electromagnetic bands, ranging from x-rays to millimeter waves, and including gravity-waves. It has derived capability priorities from current and developing Space Missions Directorate (SMD) strategic roadmaps and, where appropriate, has ensured their consistency with other NASA Strategic and Capability Roadmaps. Technology topics include optics; wavefront sensing and control and interferometry; distributed and advanced spacecraft systems; cryogenic and thermal control systems; large precision structure for observatories; and the infrastructure essential to future space telescopes and observatories.
Magnetoacoustic Spectroscopy in Superfluid He3-B

NASA Astrophysics Data System (ADS)

Davis, J. P.; Choi, H.; Pollanen, J.; Halperin, W. P.

2008-01-01

We have used the acoustic Faraday effect in superfluid He3 to perform high resolution spectroscopy of an excited state of the superfluid condensate, called the imaginary squashing mode. With acoustic cavity interferometry we measure the rotation of the plane of polarization of a transverse sound wave propagating in the direction of the magnetic field from which we determine the Zeeman energy of the mode. We interpret the Landé g factor, combined with the zero-field energies of this excited state, using the theory of Sauls and Serene, to calculate the strength of f-wave interactions in He3.
Ambient Seismic Noise Interferometry on the Island of Hawai`i

NASA Astrophysics Data System (ADS)

Ballmer, Silke

Ambient seismic noise interferometry has been successfully applied in a variety of tectonic settings to gain information about the subsurface. As a passive seismic technique, it extracts the coherent part of ambient seismic noise in-between pairs of seismic receivers. Measurements of subtle temporal changes in seismic velocities, and high-resolution tomographic imaging are then possible - two applications of particular interest for volcano monitoring. Promising results from other volcanic settings motivate its application in Hawai'i, with this work being the first to explore its potential. The dataset used for this purpose was recorded by the Hawaiian Volcano Observatory's permanent seismic network on the Island of Hawai'i. It spans 2.5 years from 5/2007 to 12/2009 and covers two distinct sources of volcanic tremor. After applying standard processing for ambient seismic noise interferometry, we find that volcanic tremor strongly affects the extracted noise information not only close to the tremor source, but unexpectedly, throughout the island-wide network. Besides demonstrating how this long-range observability of volcanic tremor can be used to monitor volcanic activity in the absence of a dense seismic array, our results suggest that care must be taken when applying ambient seismic noise interferometry in volcanic settings. In a second step, we thus exclude days that show signs of volcanic tremor, reducing the dataset to three months, and perform ambient seismic noise tomography. The resulting two-dimensional Rayleigh wave group velocity maps for 0.1 - 0.9 Hz compare very well with images from previous travel time tomography, both, for the main volcanic structures at low frequencies as well as for smaller features at mid-to-high frequencies - a remarkable observation for the temporally truncated dataset. These robust results suggest that ambient seismic noise tomography in Hawai'i is suitable 1) to provide a three-dimensional S-wave model for the volcanoes and 2) to be used for repeated time-sensitive tomography, even though volcanic tremor frequently obscures ambient noise analyses. However, the noise characteristics and the wavefield in Hawai'i in general remain to be investigated in more detail in order to measure unbiased temporal velocity changes.
Optical analysis of laser systems using interferometry

NASA Astrophysics Data System (ADS)

Viswanathan, V. K.; Liberman, I.; Lawrence, G.; Seery, B. D.

1980-06-01

It is noted that previous approaches of predicting focal spot parameters involved the digitization of interference patterns of the optical components and propagation of the complex amplitude and phase of the wave front throughout the system. The present paper describes an approach in which the computational procedure is extended to produce computer plots of the final emerging wave front. It is shown that this enables direct comparison with the experimentally produced wave front of the total system and makes possible the optical analysis, design, and possible optimization of laser systems. A description is given of the computational procedure and the Twyman-Green and Smartt IR interferometers constructed to verify this approach. Finally, consideration is given to the implications of the results.
Multiwavelength digital holography with wavelength-multiplexed holograms and arbitrary symmetric phase shifts.

PubMed

Tahara, Tatsuki; Otani, Reo; Omae, Kaito; Gotohda, Takuya; Arai, Yasuhiko; Takaki, Yasuhiro

2017-05-15

We propose multiwavelength in-line digital holography with wavelength-multiplexed phase-shifted holograms and arbitrary symmetric phase shifts. We use phase-shifting interferometry selectively extracting wavelength information to reconstruct multiwavelength object waves separately from wavelength-multiplexed monochromatic images. The proposed technique obtains systems of equations for real and imaginary parts of multiwavelength object waves from the holograms by introducing arbitrary symmetric phase shifts. Then, the technique derives each complex amplitude distribution of each object wave selectively and analytically by solving the two systems of equations. We formulate the algorithm in the case of an arbitrary number of wavelengths and confirm its validity numerically and experimentally in the cases where the number of wavelengths is two and three.

Cooling Effectiveness of a Modified Cold-Water Immersion Method After Exercise-Induced Hyperthermia.

PubMed

Luhring, Katherine E; Butts, Cory L; Smith, Cody R; Bonacci, Jeffrey A; Ylanan, Ramon C; Ganio, Matthew S; McDermott, Brendon P

2016-11-01

Recommended treatment for exertional heat stroke includes whole-body cold-water immersion (CWI). However, remote locations or monetary or spatial restrictions can challenge the feasibility of CWI. Thus, the development of a modified, portable CWI method would allow for optimal treatment of exertional heat stroke in the presence of these challenges. To determine the cooling rate of modified CWI (tarp-assisted cooling with oscillation [TACO]) after exertional hyperthermia. Randomized, crossover controlled trial. Environmental chamber (temperature = 33.4°C ± 0.8°C, relative humidity = 55.7% ± 1.9%). Sixteen volunteers (9 men, 7 women; age = 26 ± 4.7 years, height = 1.76 ± 0.09 m, mass = 72.5 ± 9.0 kg, body fat = 20.7% ± 7.1%) with no history of compromised thermoregulation. Participants completed volitional exercise (cycling or treadmill) until they demonstrated a rectal temperature (T re ) ≥39.0°C. After exercise, participants transitioned to a semirecumbent position on a tarp until either T re reached 38.1°C or 15 minutes had elapsed during the control (no immersion [CON]) or TACO (immersion in 151 L of 2.1°C ± 0.8°C water) treatment. The T re , heart rate, and blood pressure (reported as mean arterial pressure) were assessed precooling and postcooling. Statistical analyses included repeated-measures analysis of variance with appropriate post hoc t tests and Bonferroni correction. Before cooling, the T re was not different between conditions (CON: 39.27°C ± 0.26°C, TACO: 39.30°C ± 0.39°C; P = .62; effect size = -0.09; 95% confidence interval [CI] = -0.2, 0.1). At postcooling, the T re was decreased in the TACO (38.10°C ± 0.16°C) compared with the CON condition (38.74°C ± 0.38°C; P < .001; effect size = 2.27; 95% CI = 0.4, 0.9). The rate of cooling was greater during the TACO (0.14 ± 0.06°C/min) than the CON treatment (0.04°C/min ± 0.02°C/min; t 15 = -8.84; P < .001; effect size = 2.21; 95% CI = -0.13, -0.08). These differences occurred despite an insignificant increase in fluid consumption during exercise preceding CON (0.26 ± 0.29 L) versus TACO (0.19 ± 0.26 L; t 12 = 1.73; P = .11; effect size = 0.48; 95% CI = -0.02, 0.14) treatment. Decreases in heart rate did not differ between the TACO and CON conditions (t 15 = -1.81; P = .09; effect size = 0.45; 95% CI = -22, 2). Mean arterial pressure was greater at postcooling with TACO (84.2 ± 6.6 mm Hg) than with CON (67.0 ± 9.0 mm Hg; P < .001; effect size = 2.25; 95% CI = 13, 21). The TACO treatment provided faster cooling than did the CON treatment. When location, monetary, or spatial restrictions are present, TACO represents an effective alternative to traditional CWI in the emergency treatment of patients with exertional hyperthermia.
Beam shaping optics to enhance performance of interferometry techniques in grating manufacture

NASA Astrophysics Data System (ADS)

Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

2018-02-01

Improving of industrial holographic and interferometry techniques is of great importance in interference lithography, computer-generated holography, holographic data storage, interferometry recording of Bragg gratings as well as gratings of various types in semiconductor industry. Performance of mentioned techniques is essentially enhanced by providing a light beam with flat phase front and flat-top irradiance distribution. Therefore, transformation of Gaussian distribution of a TEM00 laser to flat-top (top hat, uniform) distribution is an important optical task. There are different refractive and diffractive beam shaping approaches used in laser industrial and scientific applications, but only few of them are capable to fulfil the optimum conditions for beam quality demanding holography and interferometry. As a solution it is suggested to apply refractive field mapping beam shaping optics πShaper, which operational principle presumes almost lossless transformation of Gaussian to flat-top beam with flatness of output wavefront, conserving of beam consistency, providing collimated low divergent output beam, high transmittance, extended depth of field, negligible wave aberration, and achromatic design provides capability to work with several lasers with different wavelengths simultaneously. High optical quality of resulting flat-top beam allows applying additional optical components to build various imaging optical systems for variation of beam size and shape to fulfil requirements of a particular application. This paper will describe design basics of refractive beam shapers and optical layouts of their applying in holography and laser interference lithography. Examples of real implementations and experimental results will be presented as well.
Static and dynamic micro deformable mirror characterization by phase-shifting and time-averaged interferometry

NASA Astrophysics Data System (ADS)

Liotard, Arnaud; Zamkotsian, Frédéric

2017-11-01

The micro-opto-electro-mechanical systems (MOEMS), based on mature technologies of micro-electronics, are essential in the design of future astronomical instruments. One of these key-components is the microdeformable mirror for wave-front correction. Very challenging topics like search of exo-planets could greatly benefit from this technology. Design, realization and characterization of micro-Deformable Mirrors are under way at Laboratoire d'Astrophysique de Marseille (LAM) in collaboration with Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS). In order to measure the surface shape and the deformation parameters during operation of these devices, a high-resolution Twyman-Green interferometer has been developed. Measurements have been done on a tiltable micro-mirror (170*100μm2) designed by LAM-LAAS and realized by an American foundry, and also on an OKO deformable mirror (15mm diameter). Static characterization is made by phase shifting interferometry and dynamic measurements have been made by quantitative time-averaged interferometry. The OKO mirror has an actuator stroke of 370+/-10nm for 150V applied and its resonant frequency is 1170+/-50 Hz, and the tiltable mirror has a rotation cut-off frequency of 31+/-3 kHz.
Single spontaneous photon as a coherent beamsplitter for an atomic matter-wave

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomkovič, Jiří; Welte, Joachim; Oberthaler, Markus K.

2014-12-04

In free space the spontaneous emission of a single photon destroys motional coherence. Close to a mirror surface the reflection erases the which-path information and the single emitted photon can be regarded as a coherent beam splitter for an atomic matter-wavewhich can be verified by atom interferometry. Our experiment is a realization of the recoiling slit Gedanken experiment by Einstein.
Laser Development for Interferometry in Space

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan

2012-01-01

We are developing a laser (master oscillator) and optical amplifier for interferometric space missions, including the gravitational-wave missions NGO and OpTIIX experiment on the international space station. Our system is based on optical fiber and semiconductor laser technologies, which have evolved dramatically in the past decade. We will report on the latest status of the development work, including noise measurements and space qualification tests.
Professional Preparation regarding the Recognition and Treatment of Exertional Heat Stroke: The Student Perspective

ERIC Educational Resources Information Center

Mazerolle, Stephanie M.; Pagnotta, Kelly D.; Casa, Douglas J.; Armstrong, Lawrence; Maresh, Carl

2011-01-01

Context: Current evidence suggests rectal temperature(T[subscript re] and cold-water immersion (CWI) are the most effective means to diagnose and treat exertional heat stroke (EHS), respectively. Educators, clinicians, and students should be apprised of this evidence to guide their practice. Objective: Investigate what athletic training students…
Coherence in the presence of absorption and heating in a molecule interferometer

PubMed Central

Cotter, J. P.; Eibenberger, S.; Mairhofer, L.; Cheng, X.; Asenbaum, P.; Arndt, M.; Walter, K.; Nimmrichter, S.; Hornberger, K.

2015-01-01

Matter-wave interferometry can be used to probe the foundations of physics and to enable precise measurements of particle properties and fundamental constants. It relies on beam splitters that coherently divide the wave function. In atom interferometers, such elements are often realised using lasers by exploiting the dipole interaction or through photon absorption. It is intriguing to extend these ideas to complex molecules where the energy of an absorbed photon can rapidly be redistributed across many internal degrees of freedom. Here, we provide evidence that center-of-mass coherence can be maintained even when the internal energy and entropy of the interfering particle are substantially increased by absorption of photons from a standing light wave. Each photon correlates the molecular center-of-mass wave function with its internal temperature and splits it into a superposition with opposite momenta in addition to the beam-splitting action of the optical dipole potential. PMID:26066053
Dynamic properties of ceramic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grady, D.E.

1995-02-01

The present study offers new data and analysis on the transient shock strength and equation-of-state properties of ceramics. Various dynamic data on nine high strength ceramics are provided with wave profile measurements, through velocity interferometry techniques, the principal observable. Compressive failure in the shock wave front, with emphasis on brittle versus ductile mechanisms of deformation, is examined in some detail. Extensive spall strength data are provided and related to the theoretical spall strength, and to energy-based theories of the spall process. Failure waves, as a mechanism of deformation in the transient shock process, are examined. Strength and equation-of-state analysis ofmore » shock data on silicon carbide, boron carbide, tungsten carbide, silicon dioxide and aluminum nitride is presented with particular emphasis on phase transition properties for the latter two. Wave profile measurements on selected ceramics are investigated for evidence of rate sensitive elastic precursor decay in the shock front failure process.« less
Laser Interferometer Measurements of the Viscoelastic Properties of Tectorial Membrane Mutants

NASA Astrophysics Data System (ADS)

Jones, Gareth; Russell, Ian; Lukashkin, Andrei

2011-11-01

The visco-elastic properties of the tectorial membrane (TM) can be determined by measuring the propagation velocity of travelling waves over a range of frequencies. This study presents a new method using laser interferometry and compares the TM's material properties (sheer storage modulus, G' and viscosity, η) at basal and apical locations in wild-type mice and basal locations of three mutant groups (TectaY1870C/+, Tectb-/- and Otoa-/-). The G' and η values calculated for the wild-type mice are similar to estimates derived using other methods whereas the mutant groups all exhibit slower wave propagation velocities and reduced longitudinal coupling.
Laser system development for gravitational-wave interferometry in space

NASA Astrophysics Data System (ADS)

Numata, Kenji; Yu, Anthony W.; Camp, Jordan B.; Krainak, Michael A.

2018-02-01

A highly stable and robust laser system is a key component of the space-based Laser Interferometer Space Antenna (LISA) mission, which is designed to detect gravitational waves from various astronomical sources. The baseline architecture for the LISA laser consists of a low-power, low-noise Nd:YAG non-planar ring oscillator (NPRO) followed by a diode-pumped Yb-fiber amplifier with 2 W output. We are developing such laser system at the NASA Goddard Space Flight Center (GSFC), as well as investigating other laser options. In this paper, we will describe our progress to date and plans to demonstrate a technology readiness level (TRL) 6 LISA laser system.
Considering causal genes in the genetic dissection of kernel traits in common wheat.

PubMed

Mohler, Volker; Albrecht, Theresa; Castell, Adelheid; Diethelm, Manuela; Schweizer, Günther; Hartl, Lorenz

2016-11-01

Genetic factors controlling thousand-kernel weight (TKW) were characterized for their association with other seed traits, including kernel width, kernel length, ratio of kernel width to kernel length (KW/KL), kernel area, and spike number per m 2 (SN). For this purpose, a genetic map was established utilizing a doubled haploid population derived from a cross between German winter wheat cultivars Pamier and Format. Association studies in a diversity panel of elite cultivars supplemented genetic analysis of kernel traits. In both populations, genomic signatures of 13 candidate genes for TKW and kernel size were analyzed. Major quantitative trait loci (QTL) for TKW were identified on chromosomes 1B, 2A, 2D, and 4D, and their locations coincided with major QTL for kernel size traits, supporting the common belief that TKW is a function of other kernel traits. The QTL on chromosome 2A was associated with TKW candidate gene TaCwi-A1 and the QTL on chromosome 4D was associated with dwarfing gene Rht-D1. A minor QTL for TKW on chromosome 6B coincided with TaGW2-6B. The QTL for kernel dimensions that did not affect TKW were detected on eight chromosomes. A major QTL for KW/KL located at the distal tip of chromosome arm 5AS is being reported for the first time. TaSus1-7A and TaSAP-A1, closely linked to each other on chromosome 7A, could be related to a minor QTL for KW/KL. Genetic analysis of SN confirmed its negative correlation with TKW in this cross. In the diversity panel, TaSus1-7A was associated with TKW. Compared to the Pamier/Format bi-parental population where TaCwi-A1a was associated with higher TKW, the same allele reduced grain yield in the diversity panel, suggesting opposite effects of TaCwi-A1 on these two traits.
Cold-Water Immersion for Hyperthermic Humans Wearing American Football Uniforms

PubMed Central

Miller, Kevin C.; Swartz, Erik E.; Long, Blaine C.

2015-01-01

Context Current treatment recommendations for American football players with exertional heatstroke are to remove clothing and equipment and immerse the body in cold water. It is unknown if wearing a full American football uniform during cold-water immersion (CWI) impairs rectal temperature (Trec) cooling or exacerbates hypothermic afterdrop. Objective To determine the time to cool Trec from 39.5°C to 38.0°C while participants wore a full American football uniform or control uniform during CWI and to determine the uniform's effect on Trec recovery postimmersion. Design Crossover study. Setting Laboratory. Patients or Other Participants A total of 18 hydrated, physically active, unacclimated men (age = 22 ± 3 years, height = 178.8 ± 6.8 cm, mass = 82.3 ± 12.6 kg, body fat = 13% ± 4%, body surface area = 2.0 ± 0.2 m2). Intervention(s) Participants wore the control uniform (undergarments, shorts, crew socks, tennis shoes) or full uniform (control plus T-shirt; tennis shoes; jersey; game pants; padding over knees, thighs, and tailbone; helmet; and shoulder pads). They exercised (temperature approximately 40°C, relative humidity approximately 35%) until Trec reached 39.5°C. They removed their T-shirts and shoes and were then immersed in water (approximately 10°C) while wearing each uniform configuration; time to cool Trec to 38.0°C (in minutes) was recorded. We measured Trec (°C) every 5 minutes for 30 minutes after immersion. Main Outcome Measure(s) Time to cool from 39.5°C to 38.0°C and Trec. Results The Trec cooled to 38.0°C in 6.19 ± 2.02 minutes in full uniform and 8.49 ± 4.78 minutes in control uniform (t17 = −2.1, P = .03; effect size = 0.48) corresponding to cooling rates of 0.28°C·min−1 ± 0.12°C·min−1 in full uniform and 0.23°C·min−1 ± 0.11°C·min−1 in control uniform (t17 = 1.6, P = .07, effect size = 0.44). The Trec postimmersion recovery did not differ between conditions over time (F1,17 = 0.6, P = .59). Conclusions We speculate that higher skin temperatures before CWI, less shivering, and greater conductive cooling explained the faster cooling in full uniform. Cooling rates were considered ideal when the full uniform was worn during CWI, and wearing the full uniform did not cause a greater postimmersion hypothermic afterdrop. Clinicians may immerse football athletes with hyperthermia wearing a full uniform without concern for negatively affecting body-core cooling. PMID:26090706
White Light Heterodyne Interferometry SNR

DTIC Science & Technology

2015-04-09

interferometers in the visible- and near-IR, where shot - noise -limited detectors are available. In the LWIR, the advantage of a direct detection...wavebands where shot - noise -limited detection is possible with direct detection systems, the relationship changes in the mid-wave infrared (MWIR) and...flux, without either having to split the light N – 1 ways or take the extra shot - noise penalty from Fizeau beam combining light from all apertures
Atom Interferometry on Atom Chips - A Novel Approach Towards Precision Inertial Navigation System - PINS

DTIC Science & Technology

2010-06-01

Demonstration of an area-enclosing guided-atom interferometer for rotation sensing, Phys. Rev. Lett. 99, 173201 (2007). 4. Heralded Single- Magnon Quantum...excitations are quantized spin waves ( magnons ), such that transitions between its energy levels ( magnon number states) correspond to highly directional...polarization storage in the form of a single collective-spin excitation ( magnon ) that is shared between two spatially overlapped atomic ensembles
Background-Free 3D Nanometric Localization and Sub-nm Asymmetry Detection of Single Plasmonic Nanoparticles by Four-Wave Mixing Interferometry with Optical Vortices

NASA Astrophysics Data System (ADS)

Zoriniants, George; Masia, Francesco; Giannakopoulou, Naya; Langbein, Wolfgang; Borri, Paola

2017-10-01

Single nanoparticle tracking using optical microscopy is a powerful technique with many applications in biology, chemistry, and material sciences. Despite significant advances, localizing objects with nanometric position precision in a scattering environment remains challenging. Applied methods to achieve contrast are dominantly fluorescence based, with fundamental limits in the emitted photon fluxes arising from the excited-state lifetime as well as photobleaching. Here, we show a new four-wave-mixing interferometry technique, whereby the position of a single nonfluorescing gold nanoparticle of 25-nm radius is determined with 16 nm precision in plane and 3 nm axially from rapid single-point measurements at 1-ms acquisition time by exploiting optical vortices. The precision in plane is consistent with the photon shot-noise, while axially it is limited by the nano-positioning sample stage, with an estimated photon shot-noise limit of 0.5 nm. The detection is background-free even inside biological cells. The technique is also uniquely sensitive to particle asymmetries of only 0.5% ellipticity, corresponding to a single atomic layer of gold, as well as particle orientation. This method opens new ways of unraveling single-particle trafficking within complex 3D architectures.
Generalized interferometry - I: theory for interstation correlations

NASA Astrophysics Data System (ADS)

Fichtner, Andreas; Stehly, Laurent; Ermert, Laura; Boehm, Christian

2017-02-01

We develop a general theory for interferometry by correlation that (i) properly accounts for heterogeneously distributed sources of continuous or transient nature, (ii) fully incorporates any type of linear and nonlinear processing, such as one-bit normalization, spectral whitening and phase-weighted stacking, (iii) operates for any type of medium, including 3-D elastic, heterogeneous and attenuating media, (iv) enables the exploitation of complete correlation waveforms, including seemingly unphysical arrivals, and (v) unifies the earthquake-based two-station method and ambient noise correlations. Our central theme is not to equate interferometry with Green function retrieval, and to extract information directly from processed interstation correlations, regardless of their relation to the Green function. We demonstrate that processing transforms the actual wavefield sources and actual wave propagation physics into effective sources and effective wave propagation. This transformation is uniquely determined by the processing applied to the observed data, and can be easily computed. The effective forward model, that links effective sources and propagation to synthetic interstation correlations, may not be perfect. A forward modelling error, induced by processing, describes the extent to which processed correlations can actually be interpreted as proper correlations, that is, as resulting from some effective source and some effective wave propagation. The magnitude of the forward modelling error is controlled by the processing scheme and the temporal variability of the sources. Applying adjoint techniques to the effective forward model, we derive finite-frequency Fréchet kernels for the sources of the wavefield and Earth structure, that should be inverted jointly. The structure kernels depend on the sources of the wavefield and the processing scheme applied to the raw data. Therefore, both must be taken into account correctly in order to make accurate inferences on Earth structure. Not making any restrictive assumptions on the nature of the wavefield sources, our theory can be applied to earthquake and ambient noise data, either separately or combined. This allows us (i) to locate earthquakes using interstation correlations and without knowledge of the origin time, (ii) to unify the earthquake-based two-station method and noise correlations without the need to exclude either of the two data types, and (iii) to eliminate the requirement to remove earthquake signals from noise recordings prior to the computation of correlation functions. In addition to the basic theory for acoustic wavefields, we present numerical examples for 2-D media, an extension to the most general viscoelastic case, and a method for the design of optimal processing schemes that eliminate the forward modelling error completely. This work is intended to provide a comprehensive theoretical foundation of full-waveform interferometry by correlation, and to suggest improvements to current passive monitoring methods.
Dynamic speckle interferometry of microscopic processes in solid state and thin biological objects

NASA Astrophysics Data System (ADS)

Vladimirov, A. P.

2015-08-01

Modernized theory of dynamic speckle interferometry is considered. It is shown that the time-average radiation intensity has the parameters characterizing the wave phase changes. It also brings forward an expression for time autocorrelation function of the radiation intensity. It is shown that with the vanishing averaging time value the formulas transform to the prior expressions. The results of experiments with high-cycle material fatigue and cell metabolism analysis conducted using the time-averaging technique are discussed. Good reproducibility of the results is demonstrated. It is specified that the upgraded technique allows analyzing accumulation of fatigue damage, detecting the crack start moment and determining its growth velocity with uninterrupted cyclic load. It is also demonstrated that in the experiments with a cell monolayer the technique allows studying metabolism change both in an individual cell and in a group of cells.
Accuracy concerns in digital speckle photography combined with Fresnel digital holographic interferometry

NASA Astrophysics Data System (ADS)

Zhao, Yuchen; Zemmamouche, Redouane; Vandenrijt, Jean-François; Georges, Marc P.

2018-05-01

A combination of digital holographic interferometry (DHI) and digital speckle photography (DSP) allows in-plane and out-of-plane displacement measurement between two states of an object. The former can be determined by correlating the two speckle patterns whereas the latter is given by the phase difference obtained from DHI. We show that the amplitude of numerically reconstructed object wavefront obtained from Fresnel in-line digital holography (DH), in combination with phase shifting techniques, can be used as speckle patterns in DSP. The accuracy of in-plane measurement is improved after correcting the phase errors induced by reference wave during reconstruction process. Furthermore, unlike conventional imaging system, Fresnel DH offers the possibility to resize the pixel size of speckle patterns situated on the reconstruction plane under the same optical configuration simply by zero-padding the hologram. The flexibility of speckle size adjustment in Fresnel DH ensures the accuracy of estimation result using DSP.
The Abcd Formula of Phase Definition in Optical Interferometry: Combined Effect of Air Dispersion and Broad Passband

NASA Astrophysics Data System (ADS)

Mathar, Richard J.

Long-baseline interferometry detects fringes created by superposition of two beams of light collected by two telescopes pointing into a common direction. The external path difference is commonly compensated by adding a variable optical path length (delay) through air for one beam such that the optical path difference between the beams remains close to zero near the detector. The ABCD formula assigns a (wrapped) phase to the signals A to D of an interference pattern shifted by multiples of 90 degrees in phase. We study the interplay between a broad spectral passband of the optics and the dispersion of the air in the compensating delay, which leads to small deviations between the ABCD phase and the reduced, monochromatic group-delay representation of the wave packets. This adds dispersion to the effects that have been discussed for evacuated interferometers before (Milman 2005).
Input signal shaping based on harmonic frequency response function for suppressing nonlinear optical frequency in frequency-scanning interferometry

NASA Astrophysics Data System (ADS)

Zhu, Yu; Liu, Zhigang; Deng, Wen; Deng, Zhongwen

2018-05-01

Frequency-scanning interferometry (FSI) using an external cavity diode laser (ECDL) is essential for many applications of the absolute distance measurement. However, owing to the hysteresis and creep of the piezoelectric actuator inherent in the ECDL, the optical frequency scanning exhibits a nonlinearity that seriously affects the phase extraction accuracy of the interference signal and results in the reduction of the measurement accuracy. To suppress the optical frequency nonlinearity, a harmonic frequency synthesis method for shaping the desired input signal instead of the original triangular wave is presented. The effectiveness of the presented shaping method is demonstrated through the comparison of the experimental results. Compared with an incremental Renishaw interferometer, the standard deviation of the displacement measurement of the FSI system is less than 2.4 μm when driven by the shaped signal.

Very-long-baseline interferometry techniques applied to problems of geodesy, geophysics, planetary science, astronomy, and general relativity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Counselman, C.C. III

1973-09-01

Very-long-baseline interferometry (VLBI) techniques have already been used to determine the vector separations between antennas thousands of kilometers apart to within 2 m and the directions of extragalactic radio sources to 0.1'', and to track an artificial satellite of the earth and the Apollo Lunar Rover on the surface of the Moon. The relative loostions of the Apollo Lunar Surface Experiment Package (ALSEP) transmitters on the lunar surface are being measured within 1 m, and the Moon's libration is being messured to 1'' of selenocentric src. Attempts are under way to measure the solar gravitational deflection of radio waves moremore » accurately than previously possible, by means of VLBI. A wide variety of scientific problems is being attacked by VLBI techniques, which may soon be two orders of magnitude more accurate than at present. (auth)« less
Interaction of an ultrarelativistic electron bunch train with a W-band accelerating structure: High power and high gradient

DOE PAGES

Wang, D.; Antipov, S.; Jing, C.; ...

2016-02-05

Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to themore » interference of the wakefields from the two bunches, was measured as a function of bunch separation. As a result, measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.« less
On the Piezoelectric Detection of Guided Ultrasonic Waves

PubMed Central

2017-01-01

In order to quantify the wave motion of guided ultrasonic waves, the characteristics of piezoelectric detectors, or ultrasonic transducers and acoustic emission sensors, have been evaluated systematically. Such guided waves are widely used in structural health monitoring and nondestructive evaluation, but methods of calibrating piezoelectric detectors have been inadequate. This study relied on laser interferometry for the base displacement measurement of bar waves, from which eight different guided wave test set-ups are developed with known wave motion using piezoelectric transmitters. Both plates and bars of 12.7 and 6.4 mm thickness were used as wave propagation media. The upper frequency limit was 2 MHz. Output of guided wave detectors were obtained on the test set-ups and their receiving sensitivities were characterized and averaged. While each sensitivity spectrum was noisy for a detector, the averaged spectrum showed a good convergence to a unique receiving sensitivity. Twelve detectors were evaluated and their sensitivity spectra determined in absolute units. Generally, these showed rapidly dropping sensitivity with increasing frequency due to waveform cancellation on their sensing areas. This effect contributed to vastly different sensitivities to guided wave and to normally incident wave for each one of the 12 detectors tested. Various other effects are discussed and recommendations on methods of implementing the approach developed are provided. PMID:29156579
Spherical grating based x-ray Talbot interferometry.

PubMed

Cong, Wenxiang; Xi, Yan; Wang, Ge

2015-11-01

Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh-Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications.
Spherical grating based x-ray Talbot interferometry

PubMed Central

Cong, Wenxiang; Xi, Yan; Wang, Ge

2015-01-01

Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications. PMID:26520741
Spherical grating based x-ray Talbot interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cong, Wenxiang, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Xi, Yan, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Wang, Ge, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu

2015-11-15

Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme formore » a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and improves both signal visibility and dose utilization for pre-clinical and clinical applications.« less
Expression analysis of genes associated with sucrose accumulation in sugarcane (Saccharum spp. hybrids) varieties differing in content and time of peak sucrose storage

USDA-ARS?s Scientific Manuscript database

Sucrose synthesis/accumulation in sugarcane is a complex process involving many genes and regulatory sequences that control biochemical events in source-sink tissues. Among these, sucrose synthase (SuSy), sucrose-phosphate synthase (SPS), soluble acid (SAI) and cell-wall invertase (CWI) are importan...
U.S. EPA, Pesticide Product Label, TDC DICOFOL 4E, 02/19/1982

EPA Pesticide Factsheets

2011-04-21

... kJI ~ ...-I ~ ... M<1 ~ IIrf'Ie(II.-cI -- roc D«X>fOt '·E CWI be ~ 8IIOnI or 'tII"Ith ott>.f ~~ ... t9COiI ••• ded 'Pf'-r ~ • ttIouId Ml ~ ....s wtth limit or ... y ~ tIO .-piM.! ...
Ultrafast and Doppler-free femtosecondoptical ranging based on dispersivefrequency-modulated interferometry.

PubMed

Xia, Haiyun; Zhang, Chunxi

2010-03-01

An ultrafast and Doppler-free optical ranging system based on dispersive frequency-modulated interferometry is demonstrated. The principle is similar to the conventional frequency-modulated continuous-wave interferometry where the range information is derived from the beat frequency between the object signal and the reference signal. However, a passive and static frequency scanning is performed based on the chromatic dispersion of a transform-limited femtosecond pulse in the time domain. We point out that the unbalanced dispersion introduced in the Mach-Zehnder interferometer can be optimized to eliminate the frequency chirp in the temporal interferograms pertaining to the third order dispersion of the all-fiber system, if the dynamic range being considered is small. Some negative factors, such as the polarization instability of the femtosecond pulse, the power fluctuation of the optical signal and the nonuniform gain spectrum of the erbium-doped fiber amplifier lead to an obvious envelope deformation of the temporal interferograms from the Gaussian shape. Thus a new data processing method is proposed to guarantee the range resolution. In the experiment, the vibration of a speaker is measured. A range resolution of 1.59 microm is achieved with an exposure time of 394 fs at a sampling rate of 48.6 MHz.
Hardware Verification of Laser Noise Cancellation and Gravitational Wave Extraction using Time-Delay Interferometry

NASA Astrophysics Data System (ADS)

Mitryk, Shawn; Mueller, Guido

The Laser Interferometer Space Antenna (LISA) is a space-based modified Michelson interfer-ometer designed to measure gravitational radiation in the frequency range from 30 uHz to 1 Hz. The interferometer measurement system (IMS) utilizes one-way laser phase measurements to cancel the laser phase noise, reconstruct the proof-mass motion, and extract the gravitational wave (GW) induced laser phase modulations in post-processing using a technique called time-delay interferometry (TDI). Unfortunately, there exist few hard-ware verification experiments of the IMS. The University of Florida LISA Interferometry Simulator (UFLIS) is designed to perform hardware-in-the-loop simulations of the LISA interferometry system, modeling the characteris-tics of the LISA mission as accurately as possible. This depends, first, on replicating the laser pre-stabilization by locking the laser phase to an ultra-stable Zerodur cavity length reference using the PDH locking method. Phase measurements of LISA-like photodetector beat-notes are taken using the UF-phasemeter (PM) which can measure the laser BN frequency to within an accuracy of 0.22 uHz. The inter-space craft (SC) laser links including the time-delay due to the 5 Gm light travel time along the LISA arms, the laser Doppler shifts due to differential SC motion, and the GW induced laser phase modulations are simulated electronically using the electronic phase delay (EPD) unit. The EPD unit replicates the laser field propagation between SC by measuring a photodetector beat-note frequency with the UF-phasemeter and storing the information in memory. After the requested delay time, the frequency information is added to a Doppler offset and a GW-like frequency modulation. The signal is then regenerated with the inter-SC laser phase affects applied. Utilizing these components, I will present the first complete TDI simulations performed using the UFLIS. The LISA model is presented along-side the simulation, comparing the generation and measurement of LISA-like signals. Phasemeter measurements are used in post-processing and combined in the linear combinations defined by TDI, thus, canceling the laser phase and phase-lock loop noise to extract the applied GW modulation buried under the noise. Nine order of magnitude common mode laser noise cancellation is achieved at a frequency of 1 mHz and the GW signal is clearly visible after the laser and PLL noise cancellation.
A study of the stress wave factor technique for the characterization of composite materials

NASA Technical Reports Server (NTRS)

Govada, A. K.; Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.

1985-01-01

This study has investigated the potential of the Stress Wave Factor as an NDT technique for thin composite laminates. The conventional SWF and an alternate method for quantifying the SWF were investigated. Agreement between the initial SWF number, ultrasonic C-scan, inplane displacements as obtained by full field moire interferometry, and the failure location have been observed. The SWF number was observed to be the highest when measured along the fiber direction and the lowest when measured across the fibers. The alternate method for quantifying the SWF used square root of the zeroth moment (square root of M sub o) of the frequency spectrum of the received signal as a quantitative parameter. From this study it therefore appears that the stress wave factor has an excellent potential to monitor damage development in thin composite laminates.
Temporal characterization of the wave-breaking flash in a laser plasma accelerator

NASA Astrophysics Data System (ADS)

Miao, Bo; Feder, Linus; Goers, Andrew; Hine, George; Salehi, Fatholah; Wahlstrand, Jared; Woodbury, Daniel; Milchberg, Howard

2017-10-01

Wave-breaking injection of electrons into a relativistic plasma wake generated in near-critical density plasma by sub-terawatt laser pulses generates an intense ( 1 μJ) and ultra-broadband (Δλ 300 nm) radiation flash. In this work we demonstrate the spectral coherence of this radiation and measure its temporal width using single-shot supercontinuum spectral interferometry (SSSI). The measured temporal width is limited by measurement resolution to 50 fs. Spectral coherence is corroborated by PIC simulations which show that the spatial extent of the acceleration trajectory at the trapping region is small compared to the radiation center wavelength. To our knowledge, this is the first temporal and coherence characterization of wave-breaking radiation. This work is supported by the US Department of Energy, the National Science Foundation, and the Air Force Office of Scientific Research.
Spectroscopy and nonthermal processes

NASA Technical Reports Server (NTRS)

Querci, Monique

1987-01-01

Stellar spectra are analyzed to determine nonthermal processes for cool stars. A shock wave crossing model is supported by a study of the behavior of absorption and emission spectra. The shock waves are attributed to atmospheric kinetics. Circumstellar spectral lines are studied for information about gaseous circumstellar layers. The description of stellar envelopes is carried on through circumstellar dust. Characteristic properties of polarization in the dust are described in the case of specific stars, emphasizing narrowband observations in Mira, semiregular, and supergiant stars. Finally, the direct approach to measuring the angular diameters of stars and mapping the distribution of circumstellar dust and gas by lunar occultation or interferometry is discussed, using two prototype stars, an M supergiant and a dusty carbon star.
Guest Editorial Precision Surface Metrology

NASA Astrophysics Data System (ADS)

Wyant, James C.

1984-08-01

During the past two decades there have been many changes in precision surface metrology. The introduction of the laser and the large computer during the 1960s and 1970s produced many changes in testing capabilities and requirements. Several commercial interferometers became available in the 1970s, enabling people who were not necessarily experts in interferometry to use interferometers to produce better optics. Since both buyers and sellers could test optics, the quality of the optics manufactured and sold improved greatly. If a person ordered 1/10 wave optics, he would probably get 1/10 wave or better optics; if he got optics of lower quality, he would know it, and he could prove it and return it.
Short-term high temperature growth conditions during vegetative-to-reproductive phase transition irreversibly compromise cell wall invertase-mediated sucrose catalysis and microspore meiosis in grain sorghum

USDA-ARS?s Scientific Manuscript database

Grain sorghum (Sorghum bicolor L. Moench) crop yield is significantly compromised by high temperature stress-induced male sterility, and is attributed to reduced cell wall invertase (CWI)-mediated sucrose hydrolysis in microspores and anthers leading to altered carbohydrate metabolism and starch def...
Extreme ultraviolet interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, Kenneth A.

EUV lithography is a promising and viable candidate for circuit fabrication with 0.1-micron critical dimension and smaller. In order to achieve diffraction-limited performance, all-reflective multilayer-coated lithographic imaging systems operating near 13-nm wavelength and 0.1 NA have system wavefront tolerances of 0.27 nm, or 0.02 waves RMS. Owing to the highly-sensitive resonant reflective properties of multilayer mirrors and extraordinarily tight tolerances set forth for their fabrication, EUV optical systems require at-wavelength EUV interferometry for final alignment and qualification. This dissertation discusses the development and successful implementation of high-accuracy EUV interferometric techniques. Proof-of-principle experiments with a prototype EUV point-diffraction interferometer for themore » measurement of Fresnel zoneplate lenses first demonstrated sub-wavelength EUV interferometric capability. These experiments spurred the development of the superior phase-shifting point-diffraction interferometer (PS/PDI), which has been implemented for the testing of an all-reflective lithographic-quality EUV optical system. Both systems rely on pinhole diffraction to produce spherical reference wavefronts in a common-path geometry. Extensive experiments demonstrate EUV wavefront-measuring precision beyond 0.02 waves RMS. EUV imaging experiments provide verification of the high-accuracy of the point-diffraction principle, and demonstrate the utility of the measurements in successfully predicting imaging performance. Complementary to the experimental research, several areas of theoretical investigation related to the novel PS/PDI system are presented. First-principles electromagnetic field simulations of pinhole diffraction are conducted to ascertain the upper limits of measurement accuracy and to guide selection of the pinhole diameter. Investigations of the relative merits of different PS/PDI configurations accompany a general study of the most significant sources of systematic measurement errors. To overcome a variety of experimental difficulties, several new methods in interferogram analysis and phase-retrieval were developed: the Fourier-Transform Method of Phase-Shift Determination, which uses Fourier-domain analysis to improve the accuracy of phase-shifting interferometry; the Fourier-Transform Guided Unwrap Method, which was developed to overcome difficulties associated with a high density of mid-spatial-frequency blemishes and which uses a low-spatial-frequency approximation to the measured wavefront to guide the phase unwrapping in the presence of noise; and, finally, an expedient method of Gram-Schmidt orthogonalization which facilitates polynomial basis transformations in wave-front surface fitting procedures.« less
Numerical simulation of time delay interferometry for a LISA-like mission with the simplification of having only one interferometer

NASA Astrophysics Data System (ADS)

Dhurandhar, S. V.; Ni, W.-T.; Wang, G.

2013-01-01

In order to attain the requisite sensitivity for LISA, laser frequency noise must be suppressed below the secondary noises such as the optical path noise, acceleration noise etc. In a previous paper (Dhurandhar, S.V., Nayak, K.R., Vinet, J.-Y. Time delay interferometry for LISA with one arm dysfunctional. Class. Quantum Grav. 27, 135013, 2010), we have found a large family of second-generation analytic solutions of time delay interferometry with one arm dysfunctional, and we also estimated the laser noise due to residual time-delay semi-analytically from orbit perturbations due to Earth. Since other planets and solar-system bodies also perturb the orbits of LISA spacecraft and affect the time delay interferometry (TDI), we simulate the time delay numerically in this paper for all solutions with the generation number n ⩽ 3. We have worked out a set of 3-year optimized mission orbits of LISA spacecraft starting at January 1, 2021 using the CGC2.7 ephemeris framework. We then use this numerical solution to calculate the residual optical path differences in the second-generation solutions of our previous paper, and compare with the semi-analytic error estimate. The accuracy of this calculation is better than 1 cm (or 30 ps). The maximum path length difference, for all configuration calculated, is below 1 m (3 ns). This is well below the limit under which the laser frequency noise is required to be suppressed. The numerical simulation in this paper can be applied to other space-borne interferometers for gravitational wave detection with the simplification of having only one interferometer.
CURIE: Cubesat Radio Interferometry Experiment

NASA Astrophysics Data System (ADS)

Sundkvist, D. J.; Saint-Hilaire, P.; Bain, H. M.; Bale, S. D.; Bonnell, J. W.; Hurford, G. J.; Maruca, B.; Martinez Oliveros, J. C.; Pulupa, M.

2016-12-01

The CUbesat Radio Interferometry Experiment (CURIE) is a proposed two-element radio interferometer, based on proven and developed digital radio receivers and designed to fit within a Cubesat platform. CURIE will launch as a 6U Cubesat and then separate into two 3U Cubesats once in orbit. CURIE measures radio waves from 0.1-19MHz, which must be measured from space, as those frequencies fall below the cutoff imposed by Earth's ionosphere. The principal science objective for CURIE is to use radio interferometry to study radio burst emissions from solar eruptive events such as flares and coronal mass ejections (CMEs) in the inner heliosphere, providing observations important for our understanding of the heliospheric space weather environment. The influence of space weather can be felt at Earth and other planets, as radiation levels increase and lead to auroral activity and geomagnetic effects. CURIE will be able to determine the location and size of radio burst source regions and then to track their movement outward from the Sun. In addition to the primary objective CURIE will measure the gradients of the local ionospheric density and electron temperature on the spatial scale of a few kilometers, as well as create an improved map of the radio sky at these unexplored frequencies. A space based radio interferometry observatory has long been envisioned, in orbit around the Earth or the Moon, or on the far side of the Moon. Beyond its important science objectives, CURIE will prove that the concept of a dedicated space-based interferometer can be realized by using relatively cheap Cubesats. CURIE will therefore not only provide new important science results but also serve as a pathfinder in the development of new space-based radio observation techniques for helio- and astro-physics.
A novel type of very long baseline astronomical intensity interferometer

NASA Astrophysics Data System (ADS)

Borra, Ermanno F.

2013-12-01

This article presents a novel type of very long baseline astronomical interferometer that uses the fluctuations, as a function of time, of the intensity measured by a quadratic detector, which is a common type of astronomical detector. The theory on which the technique is based is validated by laboratory experiments. Its outstanding principal advantages comes from the fact that the angular structure of an astronomical object is simply determined from the visibility of the minima of the spectrum of the intensity fluctuations measured by the detector, as a function of the frequency of the fluctuations, while keeping the spacing between mirrors constant. This would allow a simple setup capable of high angular resolutions because it could use an extremely large baseline. Another major interest is that it allows for a more efficient use of telescope time because observations at a single baseline are sufficient, while amplitude and intensity interferometers need several observations at different baselines. The fact that one does not have to move the telescopes would also allow detecting faster time variations because having to move the telescopes sets a lower limit to the time variations that can be detected. The technique uses wave interaction effects and thus has some characteristics in common with intensity interferometry. A disadvantage of the technique, like in intensity interferometry, is that it needs strong sources if observing at high frequencies (e.g. the visible). This is a minor disadvantage in the radio region. At high frequencies, this disadvantage is mitigated by the fact that, like in intensity interferometry, the requirements of the optical quality of the mirrors used are far less severe than in amplitude interferometry so that poor quality large reflectors (e.g. Cherenkov telescopes) can be used in the optical region.
Ambient seismic noise interferometry in Hawai'i reveals long-range observability of volcanic tremor

USGS Publications Warehouse

Ballmer, Silke; Wolfe, Cecily; Okubo, Paul G.; Haney, Matt; Thurber, Clifford H.

2013-01-01

The use of seismic noise interferometry to retrieve Green's functions and the analysis of volcanic tremor are both useful in studying volcano dynamics. Whereas seismic noise interferometry allows long-range extraction of interpretable signals from a relatively weak noise wavefield, the characterization of volcanic tremor often requires a dense seismic array close to the source. We here show that standard processing of seismic noise interferometry yields volcanic tremor signals observable over large distances exceeding 50 km. Our study comprises 2.5 yr of data from the U.S. Geological Survey Hawaiian Volcano Observatory short period seismic network. Examining more than 700 station pairs, we find anomalous and temporally coherent signals that obscure the Green's functions. The time windows and frequency bands of these anomalous signals correspond well with the characteristics of previously studied volcanic tremor sources at Pu'u 'Ō'ō and Halema'uma'u craters. We use the derived noise cross-correlation functions to perform a grid-search for source location, confirming that these signals are surface waves originating from the known tremor sources. A grid-search with only distant stations verifies that useful tremor signals can indeed be recovered far from the source. Our results suggest that the specific data processing in seismic noise interferometry—typically used for Green's function retrieval—can aid in the study of both the wavefield and source location of volcanic tremor over large distances. In view of using the derived Green's functions to image heterogeneity and study temporal velocity changes at volcanic regions, however, our results illustrate how care should be taken when contamination by tremor may be present.

Relative Seismic Velocity Variations Correlate with Deformation at Kīlauea Volcano.

NASA Astrophysics Data System (ADS)

Donaldson, C.; Caudron, C.; Green, R. G.; White, R. S.

2016-12-01

Passive interferometry using ambient seismic noise is an appealing monitoring tool at volcanoes. The continuous nature of seismic noise provides better temporal resolution than earthquake interferometry and ambient noise may be sensitive to changes at depths that do not deform the volcano surface. Despite this, to our knowledge, no studies have yet comprehensively compared deformation and velocity at a volcano over a significant length of time. We use a volcanic tremor source (approximately 0.3 - 1.0 Hz) at Kīlauea volcano as a source for interferometry to measure relative velocity changes with time. The tremor source that dominates the cross correlations is located under the Halema'uma'u caldera at Kīlauea summit. By cross-correlating the vertical component of day-long seismic records between 200 pairs of stations, we extract coherent and temporally consistent coda wave signals with time lags of up to 70 seconds. Our resulting time series of relative velocity shows a remarkable correlation with the tilt record measured at Kīlauea summit. Kīlauea summit is continually inflating and deflating as the level of the lava lake rises and falls. During these deflation-inflation (DI) events the tilt increases (inflation), as the velocity increases, on the scale of days to weeks. In contrast, we also detect a longer-term velocity decrease between 2011-2015 as the volcano slowly inflates. We suggest that variations in velocity result from opening and closing cracks and pores due to changes in magma pressurization. Early modeling results indicate that pressurizing magma reservoirs at different depths can result in opposite changes in compression/extension at the surface. The consistent correlation of relative velocity and deformation in this study provides an opportunity to better understand the mechanism causing velocity changes, which currently limits the scope of passive interferometry as a monitoring tool.
Laser-launched flyer plate and confined laser ablation for shock wave loading: validation and applications.

PubMed

Paisley, Dennis L; Luo, Sheng-Nian; Greenfield, Scott R; Koskelo, Aaron C

2008-02-01

We present validation and some applications of two laser-driven shock wave loading techniques: laser-launched flyer plate and confined laser ablation. We characterize the flyer plate during flight and the dynamically loaded target with temporally and spatially resolved diagnostics. With transient imaging displacement interferometry, we demonstrate that the planarity (bow and tilt) of the loading induced by a spatially shaped laser pulse is within 2-7 mrad (with an average of 4+/-1 mrad), similar to that in conventional techniques including gas gun loading. Plasma heating of target is negligible, in particular, when a plasma shield is adopted. For flyer plate loading, supported shock waves can be achieved. Temporal shaping of the drive pulse in confined laser ablation allows for flexible loading, e.g., quasi-isentropic, Taylor-wave, and off-Hugoniot loading. These techniques can be utilized to investigate such dynamic responses of materials as Hugoniot elastic limit, plasticity, spall, shock roughness, equation of state, phase transition, and metallurgical characteristics of shock-recovered samples.
Off-axis digital holographic microscopy with LED illumination based on polarization filtering.

PubMed

Guo, Rongli; Yao, Baoli; Gao, Peng; Min, Junwei; Zhou, Meiling; Han, Jun; Yu, Xun; Yu, Xianghua; Lei, Ming; Yan, Shaohui; Yang, Yanlong; Dan, Dan; Ye, Tong

2013-12-01

A reflection mode digital holographic microscope with light emitting diode (LED) illumination and off-axis interferometry is proposed. The setup is comprised of a Linnik interferometer and a grating-based 4f imaging unit. Both object and reference waves travel coaxially and are split into multiple diffraction orders in the Fourier plane by the grating. The zeroth and first orders are filtered by a polarizing array to select orthogonally polarized object waves and reference waves. Subsequently, the object and reference waves are combined again in the output plane of the 4f system, and then the hologram with uniform contrast over the entire field of view can be acquired with the aid of a polarizer. The one-shot nature in the off-axis configuration enables an interferometric recording time on a millisecond scale. The validity of the proposed setup is illustrated by imaging nanostructured substrates, and the experimental results demonstrate that the phase noise is reduced drastically by an order of 68% when compared to a He-Ne laser-based result.
Shock wave interactions in hypervelocity flow

NASA Astrophysics Data System (ADS)

Sanderson, S. R.; Sturtevant, B.

1994-08-01

The impingement of shock waves on blunt bodies in steady supersonic flow is known to cause extremely high local heat transfer rates and surface pressures. Although these problems have been studied in cold hypersonic flow, the effects of dissociative relaxation processes are unknown. In this paper we report a model aimed at determining the boundaries of the possible interaction regimes for an ideal dissociating gas. Local analysis about shock wave intersection points in the pressure-flow deflection angle plane with continuation of singular solutions is the fundamental tool employed. Further, we discuss an experimental investigation of the nominally two-dimensional mean flow that results from the impingement of an oblique shock wave on the leading edge of a cylinder. The effects of variations in shock impingement geometry were visualized using differential interferometry. Generally, real gas effects are seen to increase the range of shock impingement points for which enhanced heating occurs. They also reduce the type 4 interaction supersonic jet width and influence the type 2-3 transition process.
Nitromethane ignition observed with embedded PDV optical fibers

NASA Astrophysics Data System (ADS)

Mercier, P.; Bénier, J.; Frugier, P. A.; Debruyne, M.; Crouzet, B.

For a long time, the nitromethane (NM) ignition has been observed with different means such as high-speed cameras, VISAR or optical pyrometry diagnostics. By 2000, David Goosmann (LLNL) studied solid high-explosive detonation and shock loaded metal plates by measuring velocity (Fabry-Pérot interferometry) in embedded optical fibers. For six years Photonic Doppler Velocimetry (PDV) has become a major tool to better understand the phenomena occurring in shock physics experiments. In 2006, we began to use in turn this technique and studied shock-to-detonation transition in NM. Different kinds of bare optical fibers were set in the liquid; they provided two types of velocity information; those coming from phenomena located in front of the fibers (interface velocity, shock waves, overdriven detonation wave) and those due to phenomena environing the fibers (shock or detonation waves). We achieved several shots; devices were composed of a high explosive plane wave generator ended by a metal barrier followed by a cylindrical vessel containing NM. We present results.
Applications of optical holography to applied mechanics.

NASA Technical Reports Server (NTRS)

Aprahamian, R.

1972-01-01

This paper provides a brief summary of applications of optical holography and holographic interferometry to applied solid mechanics. Basic equations commonly used in fringe interpretation are described and used to reduce the data contained on holographic interferograms. A comparison of data obtained holographically with analytical prediction is given wherever possible. Applications contained herein include front surface physics, study of bomb breakup, transverse wave propagation, study of mode shapes of panels at elevated temperatures, nondestructive testing, and vibration analysis.
Franson Interference Generated by a Two-Level System

NASA Astrophysics Data System (ADS)

Peiris, M.; Konthasinghe, K.; Muller, A.

2017-01-01

We report a Franson interferometry experiment based on correlated photon pairs generated via frequency-filtered scattered light from a near-resonantly driven two-level semiconductor quantum dot. In contrast to spontaneous parametric down-conversion and four-wave mixing, this approach can produce single pairs of correlated photons. We have measured a Franson visibility as high as 66%, which goes beyond the classical limit of 50% and approaches the limit of violation of Bell's inequalities (70.7%).
DOE Office of Scientific and Technical Information (OSTI.GOV)

Blaut, Arkadiusz

We present the results of the estimation of parameters with LISA for nearly monochromatic gravitational waves in the low and high frequency regimes for the time-delay interferometry response. Angular resolution of the detector and the estimation errors of the signal's parameters in the high frequency regimes are calculated as functions of the position in the sky and as functions of the frequency. For the long-wavelength domain we give compact formulas for the estimation errors valid on a wide range of the parameter space.
Interference, focusing and excitation of ultracold atoms

NASA Astrophysics Data System (ADS)

Kandes, M. C.; Fahy, B. M.; Williams, S. R.; Tally, C. H., IV; Bromley, M. W. J.

2011-05-01

One of the pressing technological challenges in atomic physics is to go orders-of-magnitude beyond the limits of photon-based optics by harnessing the wave-nature of dilute clouds of ultracold atoms. We have developed parallelised algorithms to perform numerical calculations of the Gross-Pitaevskii equation in up to three dimensions and with up to three components to simulate Bose-Einstein condensates. A wide-ranging array of the physics associated with atom optics-based systems will be presented including BEC-based Sagnac interferometry in circular waveguides, the focusing of BECs using Laguerre-Gauss beams, and the interactions between BECs and Ince-Gaussian laser beams and their potential applications. One of the pressing technological challenges in atomic physics is to go orders-of-magnitude beyond the limits of photon-based optics by harnessing the wave-nature of dilute clouds of ultracold atoms. We have developed parallelised algorithms to perform numerical calculations of the Gross-Pitaevskii equation in up to three dimensions and with up to three components to simulate Bose-Einstein condensates. A wide-ranging array of the physics associated with atom optics-based systems will be presented including BEC-based Sagnac interferometry in circular waveguides, the focusing of BECs using Laguerre-Gauss beams, and the interactions between BECs and Ince-Gaussian laser beams and their potential applications. Performed on computational resources via NSF grants PHY-0970127, CHE-0947087 and DMS-0923278.
Speckle reduction in optical coherence tomography images based on wave atoms

PubMed Central

Du, Yongzhao; Liu, Gangjun; Feng, Guoying; Chen, Zhongping

2014-01-01

Abstract. Optical coherence tomography (OCT) is an emerging noninvasive imaging technique, which is based on low-coherence interferometry. OCT images suffer from speckle noise, which reduces image contrast. A shrinkage filter based on wave atoms transform is proposed for speckle reduction in OCT images. Wave atoms transform is a new multiscale geometric analysis tool that offers sparser expansion and better representation for images containing oscillatory patterns and textures than other traditional transforms, such as wavelet and curvelet transforms. Cycle spinning-based technology is introduced to avoid visual artifacts, such as Gibbs-like phenomenon, and to develop a translation invariant wave atoms denoising scheme. The speckle suppression degree in the denoised images is controlled by an adjustable parameter that determines the threshold in the wave atoms domain. The experimental results show that the proposed method can effectively remove the speckle noise and improve the OCT image quality. The signal-to-noise ratio, contrast-to-noise ratio, average equivalent number of looks, and cross-correlation (XCOR) values are obtained, and the results are also compared with the wavelet and curvelet thresholding techniques. PMID:24825507
Data-based diffraction kernels for surface waves from convolution and correlation processes through active seismic interferometry

NASA Astrophysics Data System (ADS)

Chmiel, Malgorzata; Roux, Philippe; Herrmann, Philippe; Rondeleux, Baptiste; Wathelet, Marc

2018-05-01

We investigated the construction of diffraction kernels for surface waves using two-point convolution and/or correlation from land active seismic data recorded in the context of exploration geophysics. The high density of controlled sources and receivers, combined with the application of the reciprocity principle, allows us to retrieve two-dimensional phase-oscillation diffraction kernels (DKs) of surface waves between any two source or receiver points in the medium at each frequency (up to 15 Hz, at least). These DKs are purely data-based as no model calculations and no synthetic data are needed. They naturally emerge from the interference patterns of the recorded wavefields projected on the dense array of sources and/or receivers. The DKs are used to obtain multi-mode dispersion relations of Rayleigh waves, from which near-surface shear velocity can be extracted. Using convolution versus correlation with a grid of active sources is an important step in understanding the physics of the retrieval of surface wave Green's functions. This provides the foundation for future studies based on noise sources or active sources with a sparse spatial distribution.
Focusing optical waves with a rotationally symmetric sharp-edge aperture

NASA Astrophysics Data System (ADS)

Hu, Yanwen; Fu, Shenhe; Li, Zhen; Yin, Hao; Zhou, Jianying; Chen, Zhenqiang

2018-04-01

While there has been various kinds of patterned structures proposed for wave focusing, these patterned structures usually involve complicated lithographic techniques since the element size of the patterned structures should be precisely controlled in microscale or even nanoscale. Here we propose a new and straightforward method for focusing an optical plane wave in free space with a rotationally symmetric sharp-edge aperture. The focusing phenomenon of wave is realized by superposition of a portion of the higher-order symmetric plane waves generated from the sharp edges of the apertures, in contrast to previously focusing techniques which usually depend on a curved phase. We demonstrate both experimentally and theoretically the focusing effect with a series of apertures having different rotational symmetry, and find that the intensity of the hotspots could be controlled by the symmetric strength of the sharp-edge apertures. The presented results would advance the conventional wisdom that light would diffract in all directions and become expanding when it propagates through an aperture. The proposed method is easy to be processed, and might open potential applications in interferometry, image, and superresolution.
Simulating Responses of Gravitational-Wave Instrumentation

NASA Technical Reports Server (NTRS)

Armstrong, John; Edlund, Jeffrey; Vallisneri. Michele

2006-01-01

Synthetic LISA is a computer program for simulating the responses of the instrumentation of the NASA/ESA Laser Interferometer Space Antenna (LISA) mission, the purpose of which is to detect and study gravitational waves. Synthetic LISA generates synthetic time series of the LISA fundamental noises, as filtered through all the time-delay-interferometry (TDI) observables. (TDI is a method of canceling phase noise in temporally varying unequal-arm interferometers.) Synthetic LISA provides a streamlined module to compute the TDI responses to gravitational waves, according to a full model of TDI (including the motion of the LISA array and the temporal and directional dependence of the arm lengths). Synthetic LISA is written in the C++ programming language as a modular package that accommodates the addition of code for specific gravitational wave sources or for new noise models. In addition, time series for waves and noises can be easily loaded from disk storage or electronic memory. The package includes a Python-language interface for easy, interactive steering and scripting. Through Python, Synthetic LISA can read and write data files in Flexible Image Transport System (FITS), which is a commonly used astronomical data format.
Compression wave studies in Blair dolomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grady, D.E.; Hollenbach, R.E.; Schuler, K.W.

Dynamic compression wave studies have been conducted on Blair dolomite in the stress range of 0-7.0 GPa. Impact techniques were used to generate stress impulse input functions, and diffuse surface laser interferometry provided the dynamic instrumentation. Experimental particle velocity profiles obtained by this method were coupled with the conservation laws of mass and momentum to determine the stress-strain and stress-modulus constitutive properties of the material. Comparison between dynamic and quasistatic uniaxial stress-strain curves uncovered significant differences. Energy dissipated in a complete load and unload cycle differed by almost an order of magnitude and the longitudinal moduli differed by as muchmore » as a factor of two. Blair dolomite was observed to yield under dynamic loading at 2.5 GPa. Below 2.5 GPa the loading waves had a finite risetime and exhibited steady propagation. A finite linear viscoelastic constitutive model satisfactorily predicted the observed wave propagation. We speculate that dynamic properties of preexisting cracks provides a physical mechanism for both the rate dependent steady wave behavior and the difference between dynamic and quasistatic response.« less
Time-lapse CO2 monitoring using ambient-noise seismic interferometry: a feasibility study from Ketzin, Germany

NASA Astrophysics Data System (ADS)

Boullenger, Boris; Verdel, Arie; Paap, Bob; Thorbecke, Jan; Draganov, Deyan

2015-04-01

Seismic interferometry applied to ambient-noise measurements allows retrieval of the Green's function between two seismic receivers, by cross-correlating their recordings, as if from a source at one of the receivers. We propose to use ambient-noise seismic interferometry (ANSI) to retrieve reflection data. The time-lapse differences between different vintages of the retrieved data may help characterize property changes within a geologic reservoir with varying CO2 saturation. We test the feasibility of this time-lapse passive seismic method with numerical experiments based on the CO2-storage site of Ketzin, Germany. Ambient-noise recordings from Ketzin exhibit significant passive body-wave energy (from natural tremors or induced seismicity in the vicinity of the reservoir), which is advantageous to retrieve reflections with ANSI. The ANSI numerical experiments aim to understand what the requirements are for the recorded body-wave noise to retrieve the time-lapse reflection signal caused by an increase of CO2 saturation in the reservoir. For this purpose, we design two velocity scenarios at Ketzin: a base scenario before the injection of CO2, and a repeat scenario corresponding to a P-wave velocity decline in the reservoir by 20 percent. For both scenarios, we simulate passive seismic experiments of body-wave noise recordings that may take several days or months to record in the field. The passive recordings are obtained by modelling global (direct wave, internal and surface multiples) transmission responses from band-limited subsurface noise sources, randomly triggered in space and time. The time-lapse reflection signal is obtained by taking the differences between the base and the repeat retrieved reflection data (virtual common-shot gathers). We found that the time-lapse signal is still recovered with ANSI even if the base and repeat retrieved reflection data are partially polluted with artifacts. This means that uneven illumination of the array does not necessarily exclude acceptable time-lapse signal retrieval. Furthermore, the clarity of the time-lapse signal at the reservoir level increases with increasing repeatability of the two passive experiments. The increase in repeatability is achieved when the contributing noise sources form denser clusters that share analogous spatial coverage. To support the merits of the numerical experiments, we applied ANSI (by auto-correlation) to three days of Ketzin passive field-data and compare the retrieved responses with the modelling results. The data are recorded at a permanent array of sensors (hydrophones and geophones) installed above the injection site. We used the records from the buried line of the array that consists of sensors lying at 50-meters depth. These records are less contaminated with surface noise and preserve passive body-wave events better than surface-recorded data. The retrieved responses exhibit significant correspondence with the existing active-seismic field data as well as with our modelled ANSI and active responses. Key reflection events seem to be retrieved at the expected arrival times and support the idea that the settings and characteristics of the ambient noise at Ketzin offer good potential for time-lapse ANSI to monitor CO2 sequestration.
Atmospheric Phase Delay in Sentinel SAR Interferometry

NASA Astrophysics Data System (ADS)

Krishnakumar, V.; Monserrat, O.; Crosetto, M.; Crippa, B.

2018-04-01

The repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth's surface, especially for mapping the Earth's topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth's atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation measurements.
A Method to Retrieve the Multi-Receiver Moho Reflection Response from SH-Wave Scattering Coda in the Radiative Transfer Regime

NASA Astrophysics Data System (ADS)

Hartstra, I.; Wapenaar, C. P. A.

2015-12-01

We discuss a method to retrieve the multi-receiver Moho reflection response by interferometry from SH-wave coda in the 0.5-3 Hz frequency range. An image derived from a reflection response with a well defined virtual source would provide deterministic impedance contrasts, which can complement transmission tomography. For an accurate retrieval, cross-correlation interferometry requires the coda wave field to sample the imaging target and isotropically illuminate the receiver array. When these illumination requirements are not or only partially met, the stationary phase cannot be fully captured and artifacts will contaminate the retrieved reflection response. Here we conduct numerical scalar 2D finite difference simulations to investigate the challenging situation in which only shallow crustal earthquake sources illuminate the Moho and the response is recorded by a 2D linear array. We quantify to what extent the prevalence of scatterers in the crust can improve the illumination conditions and thus the retrieval of the Moho reflection. The accuracy of the retrieved reflection is evaluated for two physically different scattering regimes: the Rayleigh and Mie regime. We only use the earlier part of the scattering coda, because we have found that the later diffusive part does not significantly improve the retrieval. The density of the spherical scatterers is varied in order to change the scattering mean free path. This characteristic length scale is calculated for each model with the 2D radiative transfer equation, which is the governing equation in the earlier part of the scattering coda. The experiment is repeated for models of different geological settings derived from existing S-wave tomographies, which vary in Moho depth and reflectivity. The scattering mean free path can be approximated for real data if intrinsic attenuation is known, because the wavenumber-dependent scattering attenuation of the coherent wave amplitude is dependent on the scattering mean free path. This link makes it possible to determine in which spatial and temporal bandwidth retrieval is most optimal for a specific geological setting.
The evaluation of phasemeter prototype performance for the space gravitational waves detection.

PubMed

Liu, He-Shan; Dong, Yu-Hui; Li, Yu-Qiong; Luo, Zi-Ren; Jin, Gang

2014-02-01

Heterodyne laser interferometry is considered as the most promising readout scheme for future space gravitational wave detection missions, in which the gravitational wave signals disguise as small phase variances within the heterodyne beat note. This makes the phasemeter, which extracts the phase information from the beat note, the key device to this system. In this paper, a prototype of phasemeter based on digital phase-locked loop technology is developed, and the major noise sources which may contribute to the noise spectra density are analyzed in detail. Two experiments are also carried out to evaluate the performance of the phasemeter prototype. The results show that the sensitivity is achieved 2π μrad/√Hz in the frequency range of 0.04 Hz-10 Hz. Due to the effect of thermal drift, the noise obviously increases with the frequencies down to 0.1 mHz.
The evaluation of phasemeter prototype performance for the space gravitational waves detection

NASA Astrophysics Data System (ADS)

Liu, He-Shan; Dong, Yu-Hui; Li, Yu-Qiong; Luo, Zi-Ren; Jin, Gang

2014-02-01

Heterodyne laser interferometry is considered as the most promising readout scheme for future space gravitational wave detection missions, in which the gravitational wave signals disguise as small phase variances within the heterodyne beat note. This makes the phasemeter, which extracts the phase information from the beat note, the key device to this system. In this paper, a prototype of phasemeter based on digital phase-locked loop technology is developed, and the major noise sources which may contribute to the noise spectra density are analyzed in detail. Two experiments are also carried out to evaluate the performance of the phasemeter prototype. The results show that the sensitivity is achieved 2π μrad/√Hz in the frequency range of 0.04 Hz-10 Hz. Due to the effect of thermal drift, the noise obviously increases with the frequencies down to 0.1 mHz.
Droplet characteristic measurement in Fourier interferometry imaging and behavior at the rainbow angle.

PubMed

Briard, Paul; Saengkaew, Sawitree; Wu, Xuecheng; Meunier-Guttin-Cluzel, Siegfried; Chen, Linghong; Cen, Kefa; Gréhan, Gérard

2013-01-01

This paper presents the possibility of measuring the three-dimensional (3D) relative locations and diameters of a set of spherical particles and discusses the behavior of the light recorded around the rainbow angle, an essential step toward refractive index measurements. When a set of particles is illuminated by a pulsed incident wave, the particles act as spherical light wave sources. When the pulse duration is short enough to fix the particle location (typically about 10 ns), interference fringes between these different spherical waves can be recorded. The Fourier transform of the fringes divides the complex fringe systems into a series of spots, with each spot characterizing the interference between a pair of particles. The analyses of these spots (in position and shape) potentially allow the measurement of particle characteristics (3D relative position, particle diameter, and particle refractive index value).

Atomic Interferometric Gravitational-Wave Space Observatory (AIGSO)

NASA Astrophysics Data System (ADS)

Gao, Dong-Feng; Wang, Jin; Zhan, Ming-Sheng

2018-01-01

We propose a space-borne gravitational-wave detection scheme, called atom interferometric gravitational-wave space observatory (AIGSO). It is motivated by the progress in the atomic matter-wave interferometry, which solely utilizes the standing light waves to split, deflect and recombine the atomic beam. Our scheme consists of three drag-free satellites orbiting the Earth. The phase shift of AIGSO is dominated by the Sagnac effect of gravitational-waves, which is proportional to the area enclosed by the atom interferometer, the frequency and amplitude of gravitational-waves. The scheme has a strain sensitivity < {10}-20/\\sqrt{{Hz}} in the 100 mHz-10 Hz frequency range, which fills in the detection gap between space-based and ground-based laser interferometric detectors. Thus, our proposed AIGSO can be a good complementary detection scheme to the space-borne laser interferometric schemes, such as LISA. Considering the current status of relevant technology readiness, we expect our AIGSO to be a promising candidate for the future space-based gravitational-wave detection plan. Supported by the National Key Research Program of China under Grant No. 2016YFA0302002, the National Science Foundation of China under Grant Nos. 11227803 and 91536221, and the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No. XDB21010100
New Astrometric Limits on the Stochastic Gravitational Wave Background

NASA Astrophysics Data System (ADS)

Darling, Jeremiah K.; Truebenbach, Alexandra; Paine, Jennie

2018-06-01

We present new limits on the low frequency (f < 10-8 Hz) stochastic gravitational wave background using correlated extragalactic proper motions. The familiar methods for gravitational wave detection are ground- and space-based laser interferometry, pulsar timing, and polarization of the cosmic microwave background. Astrometry offers an additional path to gravitational wave detection because gravitational waves deflect the light rays of extragalactic objects, creating apparent proper motions in a quadrupolar (and higher order modes) pattern. Astrometry is sensitive to gravitational waves with frequencies between roughly 10-18 Hz and 10-8 Hz (between H0 and 1/3 yr-1), which overlaps and bridges the pulsar timing and CMB polarization regimes. We present the methods and results of two complementary approaches to astrometric gravitational wave detection: (1) a small ~500-object radio interferometric sample with low per-source proper motion uncertainty but large intrinsic proper motions caused by radio jets, and (2) a thousand-fold larger sample with large per-source uncertainties that has small intrinsic proper motions (Gaia active galactic nuclei). Both approaches produce limits on ΩGW, the energy density of gravitational waves as a fraction of the cosmological critical energy density.The authors acknowledge support from the NSF grant AST-1411605 and the NASA grant 14-ATP14-0086.
Holographic measurement of wave propagation in axi-symmetric shells

NASA Technical Reports Server (NTRS)

Evensen, D. A.; Aprahamian, R.; Jacoby, J. L.

1972-01-01

The report deals with the use of pulsed, double-exposure holographic interferometry to record the propagation of transverse waves in thin-walled axi-symmetric shells. The report is subdivided into sections dealing with: (1) wave propagation in circular cylindrical shells, (2) wave propagation past cut-outs and stiffeners, and (3) wave propagation in conical shells. Several interferograms are presented herein which show the waves reflecting from the shell boundaries, from cut-outs, and from stiffening rings. The initial response of the shell was nearly axi-symmetric in all cases, but nonsymmetric modes soon appeared in the radial response. This result suggests that the axi-symmetric response of the shell may be dynamically unstable, and thus may preferentially excite certain circumferential harmonics through parametric excitation. Attempts were made throughout to correlate the experimental data with analysis. For the most part, good agreement between theory and experiment was obtained. Occasional differences were attributed primarily to simplifying assumptions used in the analysis. From the standpoint of engineering applications, it is clear that pulsed laser holography can be used to obtain quantitative engineering data. Areas of dynamic stress concentration, stress concentration factors, local anomalies, etc., can be readily determined by holography.
The LISA benchtop simulator at the University of Florida

NASA Astrophysics Data System (ADS)

Thorpe, James; Cruz, Rachel; Guntaka, Sridhar; Mueller, Guido

2006-11-01

The Laser Interferometer Space Antenna (LISA) is a joint NASA-ESA mission to detect gravitational radiation in space. The detector is designed to see gravitational waves from various exciting sources in the frequency range of 3x10-5 to 1 Hz. LISA consists of three spacecraft forming a triangle with 5x10^9 m long arms. The spacecraft house proof masses and act to shield the proof masses from external forces so that they act as freely-falling test particles of the gravitational radiation. Laser interferometry is used to monitor the distance between proof masses on different spacecraft and will be designed to see variations on the order of 10 pm. Pre-stabilization, arm-locking, and time delay interferometry (TDI) will be employed to meet this sensitivity. At the University of Florida, we are developing an experimental LISA simulator to test aspects of LISA interferometry. The foundation of the simulator is a pair of cavity-stabilized lasers that provide realistic, LISA-like phase noise for our measurements. The light travel time between spacecraft is recreated in the lab by use of an electronic phase delay technique. Initial tests of the simulator have focused on phasemeter implementation, first-generation TDI, and arm-locking. We will present results from these experiments as well as discuss current and future upgrades in the effort to make the LISA simulator as realistic as possible.
Optical Diagnostic System For Observation Of Laser-Produced Shock Waves

NASA Astrophysics Data System (ADS)

Wilke, Mark D.; Stone, Sidney N.

1980-11-01

Several standard plasma and gas dynamic diagnostic techniques have been integrated into a system for observing the formation and propagation of high-power Nd:glass-laser generated one- and two-dimensional shockwaves in air from 0.1 torr to atmospheric pres-sures. Diagnostics include either single-frame, two-wavelength holographic ruby-laser interferometry or single-frame, single-wavelength interferometry with ten frames of shadow-graphy. Streaks or ten frames of the early luminous shocked region also are taken on all shots, as well as time-resolved luminosity measurements using high-speed biplanar vacuum photodiodes with various wavelength interference filters. Shadowgraphy frames are 200-ns long at 1-μs intervals, while emission frames are variable with a maximum 10-ns exposure and 50-ns interval. Both the streak mode and emission measurements with the vacuum diode allow subnanosecond time resolution. The interferometry provides 20-ns exposures from 500 ns to late times. Methods for reducing and interpreting the data have been, or are currently being, developed. Interactive computer programs for digitizing the fringe patterns provide fringe-shift profiles for Abel inversion. This has provided neutral gas and electron density information in the spherical, one-dimensional cases. Diagrams and photographs of the experiment will be shown as well as examples of the data that have been taken. Methods for data reduction will be outlined and some of the results shown.
Transcriptomic and molecular genetic analysis of the cell wall salvage response of Aspergillus niger to the absence of galactofuranose synthesis.

PubMed

Park, Joohae; Hulsman, Mark; Arentshorst, Mark; Breeman, Matthijs; Alazi, Ebru; Lagendijk, Ellen L; Rocha, Marina C; Malavazi, Iran; Nitsche, Benjamin M; van den Hondel, Cees A M J J; Meyer, Vera; Ram, Arthur F J

2016-09-01

The biosynthesis of cell surface-located galactofuranose (Galf)-containing glycostructures such as galactomannan, N-glycans and O-glycans in filamentous fungi is important to secure the integrity of the cell wall. UgmA encodes an UDP-galactopyranose mutase, which is essential for the formation of Galf. Consequently, the ΔugmA mutant lacks Galf-containing molecules. Our previous work in Aspergillus niger work suggested that loss of function of ugmA results in activation of the cell wall integrity (CWI) pathway which is characterized by increased expression of the agsA gene, encoding an α-glucan synthase. In this study, the transcriptional response of the ΔugmA mutant was further linked to the CWI pathway by showing the induced and constitutive phosphorylation of the CWI-MAP kinase in the ΔugmA mutant. To identify genes involved in cell wall remodelling in response to the absence of galactofuranose biosynthesis, a genome-wide expression analysis was performed using RNAseq. Over 400 genes were higher expressed in the ΔugmA mutant compared to the wild-type. These include genes that encode enzymes involved in chitin (gfaB, gnsA, chsA) and α-glucan synthesis (agsA), and in β-glucan remodelling (bgxA, gelF and dfgC), and also include several glycosylphosphatidylinositol (GPI)-anchored cell wall protein-encoding genes. In silico analysis of the 1-kb promoter regions of the up-regulated genes in the ΔugmA mutant indicated overrepresentation of genes with RlmA, MsnA, PacC and SteA-binding sites. The importance of these transcription factors for survival of the ΔugmA mutant was analysed by constructing the respective double mutants. The ΔugmA/ΔrlmA and ΔugmA/ΔmsnA double mutants showed strong synthetic growth defects, indicating the importance of these transcription factors to maintain cell wall integrity in the absence of Galf biosynthesis. © 2016 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.
Composite-Light-Pulse Technique for High-Precision Atom Interferometry

NASA Astrophysics Data System (ADS)

Berg, P.; Abend, S.; Tackmann, G.; Schubert, C.; Giese, E.; Schleich, W. P.; Narducci, F. A.; Ertmer, W.; Rasel, E. M.

2015-02-01

We realize beam splitters and mirrors for atom waves by employing a sequence of light pulses rather than individual ones. In this way we can tailor atom interferometers with improved sensitivity and accuracy. We demonstrate our method of composite pulses by creating a symmetric matter-wave interferometer which combines the advantages of conventional Bragg- and Raman-type concepts. This feature leads to an interferometer with a high immunity to technical noise allowing us to devise a large-area Sagnac gyroscope yielding a phase shift of 6.5 rad due to the Earth's rotation. With this device we achieve a rotation rate precision of 120 nrad s-1 Hz-1 /2 and determine the Earth's rotation rate with a relative uncertainty of 1.2%.
Design and construction of prototype radio antenna for shortest radio wavelengths

NASA Technical Reports Server (NTRS)

Leighton, R. B.

1975-01-01

A paraboloid radio antenna of 10.4 meters diameter, 0.41 meter focal length was constructed and its successful completion is described. The surface accuracy of the antenna is at least four times better than any existing antenna in its class size (50 micrometers rms). Antenna design specifications (i.e., for mounting, drive motors, honeycomb structures) are discussed and engineering drawings and photographs of antenna components are shown. The antenna will be used for millimeter-wave interferometry and sub-millimeter wave radiometry over a full frequency range (up to approximately 860 GHz). The antenna will also be moveable (for interferometric use) between reinforced concrete pads by rail. The effects of the weather and gravity on antenna performance are briefly discussed.
Polarization interferometry for real-time spectroscopic plasmonic sensing.

PubMed

Otto, Lauren M; Mohr, Daniel A; Johnson, Timothy W; Oh, Sang-Hyun; Lindquist, Nathan C

2015-03-07

We present quantitative, spectroscopic polarization interferometry phase measurements on plasmonic surfaces for sensing applications. By adding a liquid crystal variable wave plate in our beam path, we are able to measure phase shifts due to small refractive index changes on the sensor surface. By scanning in a quick sequence, our technique is extended to demonstrate real-time measurements. While this optical technique is applicable to different sensor geometries-e.g., nanoparticles, nanogratings, or nanoapertures-the plasmonic sensors we use here consist of an ultrasmooth gold layer with buried linear gratings. Using these devices and our phase measurement technique, we calculate a figure of merit that shows improvement over measuring only surface plasmon resonance shifts from a reflected intensity spectrum. To demonstrate the general-purpose versatility of our phase-resolved measurements, we also show numerical simulations with another common device architecture: periodic plasmonic slits. Since our technique inherently measures both the intensity and phase of the reflected or transmitted light simultaneously, quantitative sensor device characterization is possible.
Phase coherence and Andreev reflection in topological insulator devices

DOE PAGES

Finck, A. D. K.; Kurter, C.; Hor, Y. S.; ...

2014-11-04

Topological insulators (TIs) have attracted immense interest because they host helical surface states. Protected by time-reversal symmetry, they are robust to nonmagnetic disorder. When superconductivity is induced in these helical states, they are predicted to emulate p-wave pairing symmetry, with Majorana states bound to vortices. Majorana bound states possess non-Abelian exchange statistics that can be probed through interferometry. Here, we take a significant step towards Majorana interferometry by observing pronounced Fabry-Pérot oscillations in a TI sandwiched between a superconducting and a normal lead. For energies below the superconducting gap, we observe a doubling in the frequency of the oscillations, arisingmore » from an additional phase from Andreev reflection. When a magnetic field is applied perpendicular to the TI surface, a number of very sharp and gate-tunable conductance peaks appear at or near zero energy, which has consequences for interpreting spectroscopic probes of Majorana fermions. Our results show that TIs are a promising platform for exploring phase-coherent transport in a solid-state system.« less
Experimental demonstration of deep frequency modulation interferometry.

PubMed

Isleif, Katharina-Sophie; Gerberding, Oliver; Schwarze, Thomas S; Mehmet, Moritz; Heinzel, Gerhard; Cervantes, Felipe Guzmán

2016-01-25

Experiments for space and ground-based gravitational wave detectors often require a large dynamic range interferometric position readout of test masses with 1 pm/√Hz precision over long time scales. Heterodyne interferometer schemes that achieve such precisions are available, but they require complex optical set-ups, limiting their scalability for multiple channels. This article presents the first experimental results on deep frequency modulation interferometry, a new technique that combines sinusoidal laser frequency modulation in unequal arm length interferometers with a non-linear fit algorithm. We have tested the technique in a Michelson and a Mach-Zehnder Interferometer topology, respectively, demonstrated continuous phase tracking of a moving mirror and achieved a performance equivalent to a displacement sensitivity of 250 pm/Hz at 1 mHz between the phase measurements of two photodetectors monitoring the same optical signal. By performing time series fitting of the extracted interference signals, we measured that the linearity of the laser frequency modulation is on the order of 2% for the laser source used.
Concepts and technology development towards a platform for macroscopic quantum experiments in space

NASA Astrophysics Data System (ADS)

Kaltenbaek, Rainer

Tremendous progress has been achieved in space technology over the last decade. This technological heritage promises enabling applications of quantum technology in space already now or in the near future. Heritage in laser and optical technologies from LISA Pathfinder comprises core technologies required for quantum optical experiments. Low-noise micro-thruster technology from GAIA allows achieving an impressive quality of microgravity, and passive radiative cooling approaches as in the James Webb Space Telescope may be adapted for achieving cryogenic temperatures. Developments like these have rendered space an increasingly attractive platform for quantum-enhanced sensing and for fundamental tests of physics using quantum technology. In particular, there already have been significant efforts towards ralizing atom interferometry and atomic clocks in space as well as efforts to harness space as an environment for fundamental tests of physics using quantum optomechanics and high-mass matter-wave interferometry. Here, we will present recent efforts in spacecraft design and technology development towards this latter goal in the context of the mission proposal MAQRO.
One-shot phase-shifting phase-grating interferometry with modulation of polarization: case of four interferograms.

PubMed

Rodriguez-Zurita, Gustavo; Meneses-Fabian, Cruz; Toto-Arellano, Noel-Ivan; Vázquez-Castillo, José F; Robledo-Sánchez, Carlos

2008-05-26

An experimental setup for optical phase extraction from 2-D interferograms using a one-shot phase-shifting technique able to achieve four interferograms with 90 degrees phase shifts in between is presented. The system uses a common-path interferometer consisting of two windows in the input plane and a phase grating in Fourier plane as its pupil. Each window has a birefringent wave plate attached in order to achieve nearly circular polarization of opposite rotations one respect to the other after being illuminated with a 45 degrees linear polarized beam. In the output, interference of the fields associated with replicated windows (diffraction orders) is achieved by a proper choice of the windows spacing with respect to the grating period. The phase shifts to achieve four interferograms simultaneously to perform phase-shifting interferometry can be obtained by placing linear polarizers on each diffraction orders before detection at an appropriate angle. Some experimental results are shown.
Seismic Interferometry at a Large, Dense Array: Capturing the Wavefield at the Source Physics Experiment

NASA Astrophysics Data System (ADS)

Matzel, E.; Mellors, R. J.; Magana-Zook, S. A.

2016-12-01

Seismic interferometry is based on the observation that the Earth's background wavefield includes coherent energy, which can be recovered by observing over long time periods, allowing the incoherent energy to cancel out. The cross correlation of the energy recorded at a pair of stations results in an estimate of the Green's Function (GF) and is equivalent to the record of a simple source located at one of the stations as recorded by the other. This allows high resolution imagery beneath dense seismic networks even in areas of low seismicity. The power of these inter-station techniques increases rapidly as the number of seismometers in a network increases. For large networks the number of correlations computed can run into the millions and this becomes a "big-data" problem where data-management dominates the efficiency of the computations. In this study, we use several methods of seismic interferometry to obtain highly detailed images at the site of the Source Physics Experiment (SPE). The objective of SPE is to obtain a physics-based understanding of how seismic waves are created at and scattered near the source. In 2015, a temporary deployment of 1,000 closely spaced geophones was added to the main network of instruments at the site. We focus on three interferometric techniques: Shot interferometry (SI) uses the SPE shots as rich sources of high frequency, high signal energy. Coda interferometry (CI) isolates the energy from the scattered wavefield of distant earthquakes. Ambient noise correlation (ANC) uses the energy of the ambient background field. In each case, the data recorded at one seismometer are correlated with the data recorded at another to obtain an estimate of the GF between the two. The large network of mixed geophone and broadband instruments at the SPE allows us to calculate over 500,000 GFs, which we use to characterize the site and measure the localized wavefield. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
DOE Office of Scientific and Technical Information (OSTI.GOV)

Biedermann, G. W.; McGuinness, H. J.; Rakholia, A. V.

Here, we demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. Lastly, this interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.
Development of a Thermal Wave Interferometry System for Thin-Film Characterisation

DTIC Science & Technology

2012-10-01

describes a condition where the properties of the interface influence the phase and amplitude of the temperature oscillations at the surface. In the...The measured phase profiles are shown in Figure 13. Overall, the phase variation across the sample is significant, with a strong discontinuity in phase ...d eg ) 91.2 Hz 30 Hz 7 Hz 4 Hz Figure 13: Phase measurements across the coated sample. L1 L2 L3 L4 L5 A more rigorous validation of the
Gray matter correlates of set-shifting among neurodegenerative disease, mild cognitive impairment, and healthy older adults

PubMed Central

PA, JUDY; POSSIN, KATHERINE L.; WILSON, STEPHEN M.; QUITANIA, LOVINGLY C.; KRAMER, JOEL H.; BOXER, ADAM L.; WEINER, MICHAEL W.; JOHNSON, JULENE K.

2010-01-01

There is increasing recognition that set-shifting, a form of cognitive control, is mediated by different neural structures. However, these regions have not yet been carefully identified as many studies do not account for the influence of component processes (e.g., motor speed). We investigated gray matter correlates of set-shifting while controlling for component processes. Using the Design Fluency (DF), Trail Making Test (TMT), and Color Word Interference (CWI) subtests from the Delis-Kaplan Executive Function System (D-KEFS), we investigated the correlation between set-shifting performance and gray matter volume in 160 subjects with neurodegenerative disease, mild cognitive impairment, and healthy older adults using voxel-based morphometry. All three set-shifting tasks correlated with multiple, widespread gray matter regions. After controlling for the component processes, set-shifting performance correlated with focal regions in prefrontal and posterior parietal cortices. We also identified bilateral prefrontal cortex and the right posterior parietal lobe as common sites for set-shifting across the three tasks. There was a high degree of multicollinearity between the set-shifting conditions and the component processes of TMT and CWI, suggesting DF may better isolate set-shifting regions. Overall, these findings highlight the neuroanatomical correlates of set-shifting and the importance of controlling for component processes when investigating complex cognitive tasks. PMID:20374676
Fizeau simultaneous phase-shifting interferometry based on extended source

NASA Astrophysics Data System (ADS)

Wang, Shanshan; Zhu, Qiudong; Hou, Yinlong; Cao, Zheng

2016-09-01

Coaxial Fizeau simultaneous phase-shifting interferometer plays an important role in many fields for its characteristics of long optical path, miniaturization, and elimination of reference surface high-frequency error. Based on the matching of coherence between extended source and interferometer, orthogonal polarization reference wave and measurement wave can be obtained by Fizeau interferometry with Michelson interferometer preposed. Through matching spatial coherence length between preposed interferometer and primary interferometer, high contrast interference fringes can be obtained and additional interference fringes can be eliminated. Thus, the problem of separation of measurement and reference surface in the common optical path Fizeau interferometer is solved. Numerical simulation and principle experiment is conducted to verify the feasibility of extended source interferometer. Simulation platform is established by using the communication technique of DDE (dynamic data exchange) to connect Zemax and Matlab. The modeling of the extended source interferometer is realized by using Zemax. Matlab codes are programmed to automatically rectify the field parameters of the optical system and conveniently calculate the visibility of interference fringes. Combined with the simulation, the experimental platform of the extended source interferometer is established. After experimental research on the influence law of scattering screen granularity to interference fringes, the granularity of scattering screen is determined. Based on the simulation platform and experimental platform, the impacts on phase measurement accuracy of the imaging system aberration and collimation system aberration of the interferometer are analyzed. Compared the visibility relation curves between experimental measurement and simulation result, the experimental result is in line with the theoretical result.
Extracting the building response using seismic interferometry: Theory and application to the Millikan Library in Pasadena, California

USGS Publications Warehouse

Snieder, R.; Safak, E.

2006-01-01

The motion of a building depends on the excitation, the coupling of the building to the ground, and the mechanical properties of the building. We separate the building response from the excitation and the ground coupling by deconvolving the motion recorded at different levels in the building and apply this to recordings of the motion in the Robert A. Millikan Library in Pasadena, California. This deconvolution allows for the separation of instrinsic attenuation and radiation damping. The waveforms obtained from deconvolution with the motion in the top floor show a superposition of one upgoing and one downgoing wave. The waveforms obtained by deconvolution with the motion in the basement can be formulated either as a sum of upgoing and downgoing waves, or as a sum over normal modes. Because these deconvolved waves for late time have a monochromatic character, they are most easily analyzed with normal-mode theory. For this building we estimate a shear velocity c = 322 m/sec and a quality factor Q = 20. These values explain both the propagating waves and the normal modes.
Noncontact quantitative biomechanical characterization of cardiac muscle using shear wave imaging optical coherence tomography

PubMed Central

Wang, Shang; Lopez, Andrew L.; Morikawa, Yuka; Tao, Ge; Li, Jiasong; Larina, Irina V.; Martin, James F.; Larin, Kirill V.

2014-01-01

We report on a quantitative optical elastographic method based on shear wave imaging optical coherence tomography (SWI-OCT) for biomechanical characterization of cardiac muscle through noncontact elasticity measurement. The SWI-OCT system employs a focused air-puff device for localized loading of the cardiac muscle and utilizes phase-sensitive OCT to monitor the induced tissue deformation. Phase information from the optical interferometry is used to reconstruct 2-D depth-resolved shear wave propagation inside the muscle tissue. Cross-correlation of the displacement profiles at various spatial locations in the propagation direction is applied to measure the group velocity of the shear waves, based on which the Young’s modulus of tissue is quantified. The quantitative feature and measurement accuracy of this method is demonstrated from the experiments on tissue-mimicking phantoms with the verification using uniaxial compression test. The experiments are performed on ex vivo cardiac muscle tissue from mice with normal and genetically altered myocardium. Our results indicate this optical elastographic technique is useful as a noncontact tool to assist the cardiac muscle studies. PMID:25071943

All-optical in-depth detection of the acoustic wave emitted by a single gold nanorod

NASA Astrophysics Data System (ADS)

Xu, Feng; Guillet, Yannick; Ravaine, Serge; Audoin, Bertrand

2018-04-01

A single gold nanorod dropped on the surface of a silica substrate is used as a transient optoacoustic source of gigahertz hypersounds. We demonstrate the all-optical detection of the as-generated acoustic wave front propagating in the silica substrate. For this purpose, time-resolved femtosecond pump-probe experiments are performed in a reflection configuration. The fundamental breathing mode of the nanorod is detected at 23 GHz by interferometry, and the longitudinal acoustic wave radiated in the silica substrate is detected by time-resolved Brillouin scattering. By tuning the optical probe wavelength from 750 to 900 nm, hypersounds with wavelengths of 260-315 nm are detected in the silica substrate, with corresponding acoustic frequencies in the range of 19-23 GHz. To confirm the origin of these hypersounds, we theoretically analyze the influence of the acoustic excitation spectrum on the temporal envelope of the transient reflectivity. This analysis proves that the acoustic wave detected in the silica substrate results from the excitation of the breathing mode of the nanorod. These results pave the way for performing local in-depth elastic nanoscopy.
Inertial quantum sensors using light and matter

NASA Astrophysics Data System (ADS)

Barrett, B.; Bertoldi, A.; Bouyer, P.

2016-05-01

The past few decades have seen dramatic progress in our ability to manipulate and coherently control matter-waves. Although the duality between particles and waves has been well tested since de Broglie introduced the matter-wave analog of the optical wavelength in 1924, manipulating atoms with a level of coherence that enables one to use these properties for precision measurements has only become possible with our ability to produce atomic samples exhibiting temperatures of only a few millionths of a degree above absolute zero. Since the initial experiments a few decades ago, the field of atom optics has developed in many ways, with both fundamental and applied significance. The exquisite control of matter waves offers the prospect of a new generation of force sensors exhibiting unprecedented sensitivity and accuracy, for applications from navigation and geophysics to tests of general relativity. Thanks to the latest developments in this field, the first commercial products using this quantum technology are now available. In the future, our ability to create large coherent ensembles of atoms will allow us an even more precise control of the matter-wave and the ability to create highly entangled states for non-classical atom interferometry.
Retrieval of Body-Wave Reflections Using Ambient Noise Interferometry Using a Small-Scale Experiment

NASA Astrophysics Data System (ADS)

Dantas, Odmaksuel Anísio Bezerra; do Nascimento, Aderson Farias; Schimmel, Martin

2018-02-01

We report the retrieval of body-wave reflections from noise records using a small-scale experiment over a mature oil field. The reflections are obtained by cross-correlation and stacking of the data. We used the stacked correlograms to create virtual source-to-receiver common shot gathers and are able to obtain body-wave reflections. Surface waves that obliterate the body-waves in our noise correlations were attenuated following a standard procedure from active source seismics. Further different strategies were employed to cross-correlate and stack the data: classical geometrical normalized cross-correlation (CCGN), phase cross-correlation (PCC), linear stacking**** and phase weighted stacking (PWS). PCC and PWS are based on the instantaneous phase coherence of analytic signals. The four approaches are independent and reveal the reflections; nevertheless, the combination of PWS and CCGN provided the best results. Our analysis is based on 2145 cross-correlations of 600 s data segments. We also compare the resulted virtual shot gathers with an active 2D seismic line near the passive experiment. It is shown that our ambient noise analysis reproduces reflections which are present in the active seismic data.
Experimental investigation of turbulent mixing in post-explosion environment

NASA Astrophysics Data System (ADS)

Smith, Josh; Hargather, Michael

2015-11-01

Experiments are performed to investigate the turbulent mixing of product gases and the ambient environment in a post-explosion environment. The experiments are performed in a specially constructed shock tunnel where thermite-enhanced explosions are set off. The explosives are detonated at one end of the tunnel, producing a one-dimensional shock wave and product gas expansion which moves toward the open end of the tunnel. Optical diagnostics are applied to study the shock wave motion and the turbulent mixing of the gases after the detonation. Results are presented for schlieren, shadowgraph, and interferometry imaging of the expanding gases with simultaneous pressure measurements. An imaging spectrometer is used to identify the motion of product gas species. Results show varying shock speed with thermite mass and the identification of turbulent mixing regions.
Self-mixing interferometry: a novel yardstick for mechanical metrology

NASA Astrophysics Data System (ADS)

Donati, Silvano

2016-11-01

A novel configuration of interferometry, SMI (self-mixing interferometry), is described in this paper. SMI is attractive because it doesn't require any optical part external to the laser and can be employed in a variety of measurements - indeed it is sometimes indicated as the "interferometer for measuring without an interferometer". On processing the phase carried by the optical field upon propagation to the target under test, a number of applications have been developed, including traditional measurements related to metrology and mechanical engineering - like displacement, distance, small-amplitude vibrations, attitude angles, velocity, as well as new measurements, like mechanical stress-strain hysterisis and microstructure/MEMS electro-mechanical response. In another field, sensing of motility finds direct application in a variety of biophysical measurements, like blood pulsation, respiratory sounds, chest acoustical impedance, and blood velocity profile. And, we may also look at the amplitude of the returning signal in a SMI, and we can measure weak optical echoes - for return loss and isolation factor measurements, CD readout and scroll sensing, and THz-wave detection. Last, the fine details of the SMI waveform reveal physical parameters of the laser like the laser linewidth, coherence length, and alpha factor. Worth to be noted, SMI is also a coherent detection scheme, and measurement close to the quantum limit of received field with minimum detectable displacements of 100 pm/√Hz are currently achieved upon operation on diffusive targets, whereas in detection mode returning signal can be sensed down to attenuations of -80dB.
Logistics in Warfare: The Significance of Logistics in the Army of the Cumberland during the Tullahoma and Chickamauga Campaigns

DTIC Science & Technology

2005-06-17

the medical system for the 71 Army of the Cumberland was not as good as it could have been, it was...analysis of the Union Army and the Army of the Cumberland’s logistical system , a single commodity will be followed from the request for it in the field...acknowledge the Civil War Institute (CWI) at Gettysburg College for the many years of
High-resolution lithospheric imaging with seismic interferometry

NASA Astrophysics Data System (ADS)

Ruigrok, Elmer; Campman, Xander; Draganov, Deyan; Wapenaar, Kees

2010-10-01

In recent years, there has been an increase in the deployment of relatively dense arrays of seismic stations. The availability of spatially densely sampled global and regional seismic data has stimulated the adoption of industry-style imaging algorithms applied to converted- and scattered-wave energy from distant earthquakes, leading to relatively high-resolution images of the lower crust and upper mantle. We use seismic interferometry to extract reflection responses from the coda of transmitted energy from distant earthquakes. In theory, higher-resolution images can be obtained when migrating reflections obtained with seismic interferometry rather than with conversions, traditionally used in lithospheric imaging methods. Moreover, reflection data allow the straightforward application of algorithms previously developed in exploration seismology. In particular, the availability of reflection data allows us to extract from it a velocity model using standard multichannel data-processing methods. However, the success of our approach relies mainly on a favourable distribution of earthquakes. In this paper, we investigate how the quality of the reflection response obtained with interferometry is influenced by the distribution of earthquakes and the complexity of the transmitted wavefields. Our analysis shows that a reasonable reflection response could be extracted if (1) the array is approximately aligned with an active zone of earthquakes, (2) different phase responses are used to gather adequate angular illumination of the array and (3) the illumination directions are properly accounted for during processing. We illustrate our analysis using a synthetic data set with similar illumination and source-side reverberation characteristics as field data recorded during the 2000-2001 Laramie broad-band experiment. Finally, we apply our method to the Laramie data, retrieving reflection data. We extract a 2-D velocity model from the reflections and use this model to migrate the data. On the final reflectivity image, we observe a discontinuity in the reflections. We interpret this discontinuity as the Cheyenne Belt, a suture zone between Archean and Proterozoic terranes.
Acoustic cavitation bubbles in the kidney induced by focused shock waves in extracorporeal shock wave lithotripsy (ESWL)

NASA Astrophysics Data System (ADS)

Kuwahara, M.; Ioritani, N.; Kambe, K.; Taguchi, K.; Saito, T.; Igarashi, M.; Shirai, S.; Orikasa, S.; Takayama, K.

1990-07-01

On an ultrasonic imaging system a hyperechoic region was observed in a focal area of fucused shock waves in the dog kidney. This study was performed to learn whether cavitation bubbles are responsible for this hyperechoic region. The ultrasonic images in water of varying temperatures were not markedly different. In the flowing stream of distilled water, the stream was demonstrated as a hyperechoic region only with a mixture of air bubbles. Streams of 5%-50% glucose solutions were also demonstrated as a hyperechoic region. However, such concentration changes in living tissue, as well as thermal changes, are hardly thought to be induced. The holographic interferometry showed that the cavitation bubbles remained for more than 500 msec. in the focal area in water. This finding indicate that the bubble can remain for longer period than previously supposed. These results support the contentions that cavitation bubbles are responsible for the hyperechoic region in the kidney in situ.
MIGA: combining laser and matter wave interferometry for mass distribution monitoring and advanced geodesy

NASA Astrophysics Data System (ADS)

Canuel, B.; Pelisson, S.; Amand, L.; Bertoldi, A.; Cormier, E.; Fang, B.; Gaffet, S.; Geiger, R.; Harms, J.; Holleville, D.; Landragin, A.; Lefèvre, G.; Lhermite, J.; Mielec, N.; Prevedelli, M.; Riou, I.; Bouyer, P.

2016-04-01

The Matter-Wave laser Interferometer Gravitation Antenna, MIGA, will be a hybrid instrument composed of a network of atom interferometers horizontally aligned and interrogated by the resonant field of an optical cavity. This detector will provide measurements of sub Hertz variations of the gravitational strain tensor. MIGA will bring new methods for geophysics for the characterization of spatial and temporal variations of the local gravity field and will also be a demonstrator for future low frequency Gravitational Wave (GW) detections. MIGA will enable a better understanding of the coupling at low frequency between these different signals. The detector will be installed underground in Rustrel (FR), at the "Laboratoire Souterrain Bas Bruit" (LSBB), a facility with exceptionally low environmental noise and located far away from major sources of anthropogenic disturbances. We give in this paper an overview of the operating mode and status of the instrument before detailing simulations of the gravitational background noise at the MIGA installation site.
The advanced LIGO input optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller, Chris L., E-mail: cmueller@phys.ufl.edu; Arain, Muzammil A.; Ciani, Giacomo

The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions requiredmore » every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.« less
Toward soft-tissue elastography using digital holography to monitor surface acoustic waves

NASA Astrophysics Data System (ADS)

Li, Shiguang; Mohan, Karan D.; Sanders, William W.; Oldenburg, Amy L.

2011-11-01

Measuring the elasticity distribution inside the human body is of great interest because elastic abnormalities can serve as indicators of several diseases. We present a method for mapping elasticity inside soft tissues by imaging surface acoustic waves (SAWs) with digital holographic interferometry. With this method, we show that SAWs are consistent with Rayleigh waves, with velocities proportional to the square root of the elastic modulus greater than 2-40 kPa in homogeneous tissue phantoms. In two-layer phantoms, the SAW velocity transitions approximately from that of the lower layer to that of the upper layer as frequency is increased in agreement with the theoretical relationship between SAW dispersion and the depth-dependent stiffness profile. We also observed deformation in the propagation direction of SAWs above a stiff inclusion placed 8 mm below the surface. These findings demonstrate the potential for quantitative digital holography-based elastography of soft tissues as a noninvasive method for disease detection.
Teaching hands-on geophysics: examples from the Rū seismic network in New Zealand

NASA Astrophysics Data System (ADS)

van Wijk, Kasper; Simpson, Jonathan; Adam, Ludmila

2017-03-01

Education in physics and geosciences can be effectively illustrated by the analysis of earthquakes and the subsequent propagation of seismic waves in the Earth. Educational seismology has matured to a level where both the hard- and software are robust and user friendly. This has resulted in successful implementation of educational networks around the world. Seismic data recorded by students are of such quality that these can be used in classic earthquake location exercises, for example. But even ocean waves weakly coupled into the Earth’s crust can now be recorded on educational seismometers. These signals are not just noise, but form the basis of more recent developments in seismology, such as seismic interferometry, where seismic waves generated by ocean waves—instead of earthquakes—can be used to infer information about the Earth’s interior. Here, we introduce an earthquake location exercise and an analysis of ambient seismic noise, and present examples. Data are provided, and all needed software is freely available.
Virtual plane-wave imaging via Marchenko redatuming

NASA Astrophysics Data System (ADS)

Meles, Giovanni Angelo; Wapenaar, Kees; Thorbecke, Jan

2018-04-01

Marchenko redatuming is a novel scheme used to retrieve up- and down-going Green's functions in an unknown medium. Marchenko equations are based on reciprocity theorems and are derived on the assumption of the existence of functions exhibiting space-time focusing properties once injected in the subsurface. In contrast to interferometry but similarly to standard migration methods, Marchenko redatuming only requires an estimate of the direct wave from the virtual source (or to the virtual receiver), illumination from only one side of the medium, and no physical sources (or receivers) inside the medium. In this contribution we consider a different time-focusing condition within the frame of Marchenko redatuming that leads to the retrieval of virtual plane-wave responses. As a result, it allows multiple-free imaging using only a one-dimensional sampling of the targeted model at a fraction of the computational cost of standard Marchenko schemes. The potential of the new method is demonstrated on 2D synthetic models.
Atomic Gravitational Wave Interferometric Sensors (AGIS) in Space

NASA Astrophysics Data System (ADS)

Sugarbaker, Alex; Hogan, Jason; Johnson, David; Dickerson, Susannah; Kovachy, Tim; Chiow, Sheng-Wey; Kasevich, Mark

2012-06-01

Atom interferometers have the potential to make sensitive gravitational wave detectors, which would reinforce our fundamental understanding of gravity and provide a new means of observing the universe. We focus here on the AGIS-LEO proposal [1]. Gravitational waves can be observed by comparing a pair of atom interferometers separated over an extended baseline. The mission would offer a strain sensitivity that would provide access to a rich scientific region with substantial discovery potential. This band is not currently addressed with the LIGO or LISA instruments. We analyze systematic backgrounds that are relevant to the mission and discuss how they can be mitigated at the required levels. Some of these effects do not appear to have been considered previously in the context of atom interferometry, and we therefore expect that our analysis will be broadly relevant to atom interferometric precision measurements. Many of the techniques relevant to an AGIS mission can be investigated in the Stanford 10-m drop tower.[4pt] [1] J.M. Hogan, et al., Gen. Rel. Grav. 43, 1953-2009 (2011).
Mechanisms of anomalous compressibility of vitreous silica

NASA Astrophysics Data System (ADS)

Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Sen, Sabyasachi

2014-11-01

The anomalous compressibility of vitreous silica has been known for nearly a century, but the mechanisms responsible for it remain poorly understood. Using GHz-ultrasonic interferometry, we measured longitudinal and transverse acoustic wave travel times at pressures up to 5 GPa in vitreous silica with fictive temperatures (Tf) ranging between 985 °C and 1500 °C. The maximum in ultrasonic wave travel times-corresponding to a minimum in acoustic velocities-shifts to higher pressure with increasing Tf for both acoustic waves, with complete reversibility below 5 GPa. These relationships reflect polyamorphism in the supercooled liquid, which results in a glassy state possessing different proportions of domains of high- and low-density amorphous phases (HDA and LDA, respectively). The relative proportion of HDA and LDA is set at Tf and remains fixed on compression below the permanent densification pressure. The bulk material exhibits compression behavior systematically dependent on synthesis conditions that arise from the presence of floppy modes in a mixture of HDA and LDA domains.
Path-length-resolved dynamic light scattering in highly scattering random media: The transition to diffusing wave spectroscopy

NASA Astrophysics Data System (ADS)

Bizheva, Kostadinka K.; Siegel, Andy M.; Boas, David A.

1998-12-01

We used low coherence interferometry to measure Brownian motion within highly scattering random media. A coherence gate was applied to resolve the optical path-length distribution and to separate ballistic from diffusive light. Our experimental analysis provides details on the transition from single scattering to light diffusion and its dependence on the system parameters. We found that the transition to the light diffusion regime occurs at shorter path lengths for media with higher scattering anisotropy or for larger numerical aperture of the focusing optics.
Influence of Ultrasonic Nonlinear Propagation on Hydrophone Calibration Using Two-Transducer Reciprocity Method

NASA Astrophysics Data System (ADS)

Yoshioka, Masahiro; Sato, Sojun; Kikuchi, Tsuneo; Matsuda, Yoichi

2006-05-01

In this study, the influence of ultrasonic nonlinear propagation on hydrophone calibration by the two-transducer reciprocity method is investigated quantitatively using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. It is proposed that the correction for the diffraction and attenuation of ultrasonic waves used in two-transducer reciprocity calibration can be derived using the KZK equation to remove the influence of nonlinear propagation. The validity of the correction is confirmed by comparing the sensitivities calibrated by the two-transducer reciprocity method and laser interferometry.
Digital holographic tomography based on spectral interferometry.

PubMed

Yu, Lingfeng; Chen, Zhongping

2007-10-15

A digital holographic tomography system has been developed with the use of an inexpensive broadband light source and a fiber-based spectral interferometer. Multiple synthesized holograms (or object wave fields) of different wavelengths are obtained by transversely scanning a probe beam. The acquisition speed is improved compared with conventional wavelength-scanning digital holographic systems. The optical field of a volume around the object location is calculated by numerical diffraction from each synthesized hologram, and all such field volumes are numerically superposed to create the three-dimensional tomographic image. Experiments were performed to demonstrate the idea.
The 1975 NASA/ASEE summer faculty fellowship research program. [research in the areas of aerospace engineering, aerospace systems, and information systems

NASA Technical Reports Server (NTRS)

1975-01-01

A research program was conducted to further the professional knowledge of qualified engineering and science faculty members, to stimulate an exchange of ideas between participants and NASA engineers and scientists, and to enrich the research activities of the participants' institutions. Abstracts of reports submitted at the end of the program are presented. Topics investigated include multispectral photography, logic circuits, gravitation theories, information systems, fracture mechanics, holographic interferometry, surface acoustic wave technology, ion beams in the upper atmosphere, and hybrid microcircuits.
Quantitative holographic interferometry applied to combustion and compressible flow research

NASA Astrophysics Data System (ADS)

Bryanston-Cross, Peter J.; Towers, D. P.

1993-03-01

The application of holographic interferometry to phase object analysis is described. Emphasis has been given to a method of extracting quantitative information automatically from the interferometric fringe data. To achieve this a carrier frequency has been added to the holographic data. This has made it possible, firstly to form a phase map using a fast Fourier transform (FFT) algorithm. Then to `solve,' or unwrap, this image to give a contiguous density map using a minimum weight spanning tree (MST) noise immune algorithm, known as fringe analysis (FRAN). Applications of this work to a burner flame and a compressible flow are presented. In both cases the spatial frequency of the fringes exceed the resolvable limit of conventional digital framestores. Therefore, a flatbed scanner with a resolution of 3200 X 2400 pixels has been used to produce very high resolution digital images from photographs. This approach has allowed the processing of data despite the presence of caustics, generated by strong thermal gradients at the edge of the combustion field. A similar example is presented from the analysis of a compressible transonic flow in the shock wave and trailing edge regions.

Single frequency stable VCSEL as a compact source for interferometry and vibrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudzik, Grzegorz; Rzepka, Janusz

2010-05-28

Developing an innovative PS-DAVLL (Polarization Switching DAVLL) method of frequency stabilization, which used a ferroelectric liquid crystal cell as quarter wave plate, rubidium cell and developed ultra-stable current source, allowed to obtain a frequency stability of 10{sup -9}(frequency reproducibility of 1,2centre dot10{sup -8}) and reductions in external dimensions of laser source. The total power consumption is only 1,5 Watt. Because stabilization method used in the frequency standard is insensitive to vibration, the semiconductor laser interferometer was built for measuring range over one meter, which can also be used in industry for the accurate measurement of displacements with an accuracy ofmore » 1[mum/m]. Measurements of the VCSEL laser parameters are important from the standpoint of its use in laser interferometry or vibrometry, like narrow emission line DELTAnu{sub FWHM} = 70[MHz] equivalent of this laser type and stability of linear polarization of VCSEL laser. The undoubted advantage of the constructed laser source is the lack of mode-hopping effect during continuous work of VCSEL.« less
Laser-induced plasmas in air studied using two-color interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zefeng; Wu, Jian, E-mail: jxjawj@mail.xjtu.edu.cn; Li, Xingwen

2016-08-15

Temporally and spatially resolved density profiles of Cu atoms, electrons, and compressed air, from laser-induced copper plasmas in air, are measured using fast spectral imaging and two-color interferometry. From the intensified CCD images filtered by a narrow-band-pass filter centered at 515.32 nm, the Cu atoms expansion route is estimated and used to determine the position of the fracture surface between the Cu atoms and the air. Results indicate that the Cu atoms density at distances closer to the target (0–0.4 mm) is quite low, with the maximum density appearing at the edge of the plasma's core being ∼4.6 × 10{sup 24 }m{sup −3} at 304 ns.more » The free electrons are mainly located in the internal region of the plume, which is supposed to have a higher temperature. The density of the shock wave is (4–6) × 10{sup 25 }m{sup −3}, corresponding to air compression of a factor of 1.7–2.5.« less
Quantum Interferometry

NASA Technical Reports Server (NTRS)

Dowling, Jonathan P.

2000-01-01

Recently, several researchers, including yours truly, have been able to demonstrate theoretically that quantum photon entanglement has the potential to also revolutionize the entire field of optical interferometry, by providing many orders of magnitude improvement in interferometer sensitivity. The quantum entangled photon interferometer approach is very general and applies to many types of interferometers. In particular, without nonlocal entanglement, a generic classical interferometer has a statistical-sampling shot-noise limited sensitivity that scales like 1/Sqrt[N], where N is the number of particles (photons, electrons, atoms, neutrons) passing through the interferometer per unit time. However, if carefully prepared quantum correlations are engineered between the particles, then the interferometer sensitivity improves by a factor of Sqrt[N] (square root of N) to scale like 1/N, which is the limit imposed by the Heisenberg Uncertainty Principle. For optical (laser) interferometers operating at milliwatts of optical power, this quantum sensitivity boost corresponds to an eight-order-of-magnitude improvement of signal to noise. Applications are to tests of General Relativity such as ground and orbiting optical interferometers for gravity wave detection, Laser Interferometer Gravity Observatory (LIGO) and the European Laser Interferometer Space Antenna (LISA), respectively.
Study of the Earth's interior using measurements of sound velocities in minerals by ultrasonic interferometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Baosheng; Liebermann, Robert C.

2014-07-29

This paper reviews the progress of the technology of ultrasonic interferometry from the early 1950s to the present day. During this period of more than 60 years, sound wave velocity measurements have been increased from at pressures less than 1 GPa and temperatures less than 800 K to conditions above 25 GPa and temperatures of 1800 K. This is complimentary to other direct methods to measure sound velocities (such as Brillouin and impulsive stimulated scattering) as well as indirect methods (e.g., resonance ultrasound spectroscopy, static or shock compression, inelastic X-ray scattering). Newly-developed pressure calibration methods and data analysis procedures usingmore » a finite strain approach are described and applied to data for the major mantle minerals. The implications for the composition of the Earth’s mantle are discussed. The state-of-the-art ultrasonic experiments performed in conjunction with synchrotron X-radiation can provide simultaneous measurements of the elastic bulk and shear moduli and their pressure and temperature derivatives with direct determination of pressure. The current status and outlook/challenges for future experiments are summarized.« less
Monitoring temporal variations of seismic properties of the crust induced by the 2013 Ruisui earthquake in eastern Taiwan from coda wave interferometry with ambient seismic and strain fields

NASA Astrophysics Data System (ADS)

Dai, W. P.; Hung, S. H.; Wu, S. M.; Hsu, Y. J.

2017-12-01

Owing to the rapid development in ambient noise seismology, time-lapse variations in delay time and waveform decorrelation of coda derived from noise cross correlation (NCF) have been proved very effective to monitor slight changes in seismic velocity and scattering properties of the crust induced by various loadings such as the earthquake and healing process. In this study, we employ coda wave interferometry to detect the crustal perturbations immediately preceding and following the 2013 Mw 6.2 Ruisui Earthquake which struck the northern segment of the Longitudinal Valley Fault in eastern Taiwan, a seismically very active thrust suture zone separating the Eurasian and Philippine Sea Plate. By comparing the pre- and post-event coda waves extracted from the auto- and cross-correlation functions (ACFs and CCFs) of ambient seismic and strain fields recorded by the seismometers and borehole strainmeters, respectively, in the vicinity of the source region, we present a strong case that not only coseismic velocity reduction but also preceding decorrelation of waveforms are explicitly revealed in both the seismic and strain CCFs filtered in the secondary microseism frequency band of 0.1-0.9 Hz. Such precursory signals susceptible to the scattering properties of the crust are more unequivocally identified in the coda retrieved from the strainmeter data, suggesting that the ambient strain field can act as a more sensible probe to detect tiny structural perturbations in the critically stressed fault zone at the verge of failure. In addition to coseismic velocity changes detected in both the seismic and strain NCFs, we find quasi-periodic velocity variations that only appear in the strain retrieved coda signals, with a predominant cycle of 3-4 months correlating with the groundwater fluctuations observed at Ruisui.
RUC at TREC 2014: Select Resources Using Topic Models

DTIC Science & Technology

2014-11-01

federated search techniques in a realistic Web setting with a large number of online Web search services. This year the track contains three tasks...Selection. In CIKM 2009, pages 1277-1286. [10] M. Baillie, M. Carmen, and F. Crestani. A Multiple- Collection Latent Topic Model for Federated ... Search . Information Retrieval (2011) 14:390-412. [11] A. Bellogin, G. G. Gebremeskel, J. He, A. Said, T. Samar, A. P. de Vries. CWI and TU Delft at TREC
Declining Fortunes of Children in Middle-Class Families: Economic Inequality and Child Well-Being in the 21st Century. FCD Child and Youth Well-Being Index (CWI) Policy Brief 2011

ERIC Educational Resources Information Center

Hernandez, Donald J.

2011-01-01

Americans are struggling through the greatest economic downturn since the Great Depression. In recent years, a significant body of research and analysis has documented the breakdown of the middle class and the impact of the current financial crisis on family income, housing, and jobs. But few reports have examined these impacts through the lens of…
The Keck Cosmic Web Imager (KCWI): A Powerful New Integral Field Spectrograph for the Keck Observatory

NASA Astrophysics Data System (ADS)

Morrissey, Patrick; KCWI Team

2013-01-01

The Keck Cosmic Web Imager (KCWI) is a new facility instrument being developed for the W. M. Keck Observatory and funded for construction by the Telescope System Instrumentation Program (TSIP) of the National Science Foundation (NSF). KCWI is a bench-mounted spectrograph for the Keck II right Nasmyth focal station, providing integral field spectroscopy over a seeing-limited field up to 20"x33" in extent. Selectable Volume Phase Holographic (VPH) gratings provide high efficiency and spectral resolution in the range of 1000 to 20000. The dual-beam design of KCWI passed a Preliminary Design Review in summer 2011. The detailed design of the KCWI blue channel (350 to 700 nm) is now nearly complete, with the red channel (530 to 1050 nm) planned for a phased implementation contingent upon additional funding. KCWI builds on the experience of the Caltech team in implementing the Cosmic Web Imager (CWI), in operation since 2009 at Palomar Observatory. KCWI adds considerable flexibility to the CWI design, and will take full advantage of the excellent seeing and dark sky above Mauna Kea with a selectable nod-and-shuffle observing mode. The KCWI team is lead by Caltech (project management, design and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (program oversight and observatory interfaces).
Drill Bit Noise Illuminates the San Andreas Fault

NASA Astrophysics Data System (ADS)

Vasconcelos, Ivan; Snieder, Roel; Sava, Paul; Taylor, Tom; Malin, Peter; Chavarria, Andres

2008-09-01

Extracting the vibration response of the subsurface from noise is a rapidly growing field of research [Curtis et al., 2006; Larose et al., 2006]. We carried out broadside imaging of the San Andreas fault zone (SAFZ) using drill bit noise created in the main hole of the San Andreas Fault Observatory at Depth (SAFOD), near Parkfield, Calif. Imaging with drill bit noise is not new, but it traditionally requires the measurement of the vibrations of the drill stem [Rector and Marion, 1991]; such measurements provide the waves radiated by the drill bit. At SAFOD, these measurements were not available due to the absence of an accelerometer mounted on the drill stem. For this reason, the new technique of deconvolution interferometry was used [Vasconcelos and Snieder, 2008]. This technique extracts the waves propagating between seismometers from recordings of incoherent noise.
Brewster-angle 50%-50% beam splitter for p-polarized infrared light using a high-index quarter-wave layer deposited on a low-index prism.

PubMed

Azzam, R M A

2017-08-10

A quarter-wave layer (QWL) of high refractive index, which is deposited on a transparent prism of low refractive index, can be designed to split an incident p-polarized light beam at the Brewster angle (BA) of the air-substrate interface into p-polarized reflected and transmitted beams of equal intensity (50% each) that travel in orthogonal directions. For reflection of p-polarized light at the BA, the supported QWL functions as a free-standing (unsupported) pellicle. An exemplary design is presented that uses Si x Ge 1-x QWL deposited on an IRTRAN1 prism for applications (such as Michelson and Mach-Zehnder interferometry) with a variable compositional fraction x in the 2-6 μm mid-IR spectral range.
A study of the stress wave factor technique for the characterization of composite materials

NASA Technical Reports Server (NTRS)

Henneke, E. G., II; Duke, J. C., Jr.; Stinchcomb, W. W.; Govada, A.; Lemascon, A.

1983-01-01

A testing program was undertaken to provide an independent investigation and evaluation of the stress wave factor for characterizing the mechanical behavior of composite laminates. Some of the data which was obtained after performing a very large number of tests to determine the reproducibility of the SWF measurement is presented. It was determined that, with some optimizing of experimental parameters, the SWF value can be reproduced to within + or - 10%. Results are also given which show that, after careful calibration procedures, the lowest SWF value along the length of a specimen will correlate very closely to the site of final failure when the specimen is loaded in tension. Finally, using a moire interferometry technique, it was found that local regions having the highest in plane strains under tensile loading also had the lowest SWF values.
A continuous record of intereruption velocity change at Mount St. Helens from coda wave interferometry

USGS Publications Warehouse

Hotovec-Ellis, Alicia J.; Gomberg, Joan S.; Vidale, John; Creager, Ken C.

2014-01-01

In September 2004, Mount St. Helens volcano erupted after nearly 18 years of quiescence. However, it is unclear from the limited geophysical observations when or if the magma chamber replenished following the 1980–1986 eruptions in the years before the 2004–2008 extrusive eruption. We use coda wave interferometry with repeating earthquakes to measure small changes in the velocity structure of Mount St. Helens volcano that might indicate magmatic intrusion. By combining observations of relative velocity changes from many closely located earthquake sources, we solve for a continuous function of velocity changes with time. We find that seasonal effects dominate the relative velocity changes. Seismicity rates and repeating earthquake occurrence also vary seasonally; therefore, velocity changes and seismicity are likely modulated by snow loading, fluid saturation, and/or changes in groundwater level. We estimate hydrologic effects impart stress changes on the order of tens of kilopascals within the upper 4 km, resulting in annual velocity variations of 0.5 to 1%. The largest nonseasonal change is a decrease in velocity at the time of the deep Mw = 6.8 Nisqually earthquake. We find no systematic velocity changes during the most likely times of intrusions, consistent with a lack of observable surface deformation. We conclude that if replenishing intrusions occurred, they did not alter seismic velocities where this technique is sensitive due to either their small size or the finite compressibility of the magma chamber. We interpret the observed velocity changes and shallow seasonal seismicity as a response to small stress changes in a shallow, pressurized system.
Monitoring and analysis of thermal deformation waves with a high-speed phase measurement system.

PubMed

Taylor, Lucas; Talghader, Joseph

2015-10-20

Thermal effects in optical substrates are vitally important in determining laser damage resistance in long-pulse and continuous-wave laser systems. Thermal deformation waves in a soda-lime-silica glass substrate have been measured using high-speed interferometry during a series of laser pulses incident on the surface. Two-dimensional images of the thermal waves were captured at a rate of up to six frames per thermal event using a quantitative phase measurement method. The system comprised a Mach-Zehnder interferometer, along with a high-speed camera capable of up to 20,000 frames-per-second. The sample was placed in the interferometer and irradiated with 100 ns, 2 kHz Q-switched pulses from a high-power Nd:YAG laser operating at 1064 nm. Phase measurements were converted to temperature using known values of thermal expansion and temperature-dependent refractive index for glass. The thermal decay at the center of the thermal wave was fit to a function derived from first principles with excellent agreement. Additionally, the spread of the thermal distribution over time was fit to the same function. Both the temporal decay fit and the spatial fit produced a thermal diffusivity of 5×10^-7 m²/s.
Ultrafast dynamic response of single-crystal β-HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)

NASA Astrophysics Data System (ADS)

Zaug, Joseph M.; Austin, Ryan A.; Armstrong, Michael R.; Crowhurst, Jonathan C.; Goldman, Nir; Ferranti, Louis; Saw, Cheng K.; Swan, Raymond A.; Gross, Richard; Fried, Laurence E.

2018-05-01

We report experimental and computational studies of shock wave dynamics in single-crystal β-HMX on an ultrafast time scale. Here, a laser-based compression drive (˜1 ns in duration; stresses of up to ˜40 GPa) is used to propagate shock waves normal to the (110) and (010) lattice planes. Ultrafast time-domain interferometry measurements reveal distinct, time-dependent relationships between the shock wave velocity and particle velocity for each crystal orientation, which suggest evolving physical processes on a sub-nanosecond time scale. To help interpret the experimental data, elastic shock wave response was simulated using a finite-strain model of crystal thermoelasticity. At early propagation times (<500 ps), the model is in agreement with the data, which indicates that the mechanical response is dominated by thermoelastic deformation. The model agreement depends on the inclusion of nonlinear elastic effects in both the spherical and deviatoric stress-strain responses. This is achieved by employing an equation-of-state and a pressure-dependent stiffness tensor, which was computed via atomistic simulation. At later times (>500 ps), the crystal samples exhibit signatures of inelastic deformation, structural phase transformation, or chemical reaction, depending on the direction of wave propagation.
Relative seismic velocity variations correlate with deformation at Kīlauea volcano.

PubMed

Donaldson, Clare; Caudron, Corentin; Green, Robert G; Thelen, Weston A; White, Robert S

2017-06-01

Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical observables on a short-term time scale at a volcano over a significant length of time. We use volcanic tremor (~0.3 to 1.0 Hz) at Kīlauea as a passive source for interferometry to measure relative velocity changes with time. By cross-correlating the vertical component of day-long seismic records between ~230 station pairs, we extract coherent and temporally consistent coda wave signals with time lags of up to 120 s. Our resulting time series of relative velocity shows a remarkable correlation between relative velocity and the radial tilt record measured at Kīlauea summit, consistently correlating on a time scale of days to weeks for almost the entire study period (June 2011 to November 2015). As the summit continually deforms in deflation-inflation events, the velocity decreases and increases, respectively. Modeling of strain at Kīlauea suggests that, during inflation of the shallow magma reservoir (1 to 2 km below the surface), most of the edifice is dominated by compression-hence closing cracks and producing faster velocities-and vice versa. The excellent correlation between relative velocity and deformation in this study provides an opportunity to understand better the mechanisms causing seismic velocity changes at volcanoes, and therefore realize the potential of passive interferometry as a monitoring tool.
Seismic gradiometry using ambient seismic noise in an anisotropic Earth

NASA Astrophysics Data System (ADS)

de Ridder, S. A. L.; Curtis, A.

2017-05-01

We introduce a wavefield gradiometry technique to estimate both isotropic and anisotropic local medium characteristics from short recordings of seismic signals by inverting a wave equation. The method exploits the information in the spatial gradients of a seismic wavefield that are calculated using dense deployments of seismic arrays. The application of the method uses the surface wave energy in the ambient seismic field. To estimate isotropic and anisotropic medium properties we invert an elliptically anisotropic wave equation. The spatial derivatives of the recorded wavefield are evaluated by calculating finite differences over nearby recordings, which introduces a systematic anisotropic error. A two-step approach corrects this error: finite difference stencils are first calibrated, then the output of the wave-equation inversion is corrected using the linearized impulse response to the inverted velocity anomaly. We test the procedure on ambient seismic noise recorded in a large and dense ocean bottom cable array installed over Ekofisk field. The estimated azimuthal anisotropy forms a circular geometry around the production-induced subsidence bowl. This conforms with results from studies employing controlled sources, and with interferometry correlating long records of seismic noise. Yet in this example, the results were obtained using only a few minutes of ambient seismic noise.
The Effect of Detonation Wave Incidence Angle on the Acceleration of Flyers by Explosives Heavily Laden with Inert Additives

NASA Astrophysics Data System (ADS)

Loiseau, Jason; Georges, William; Frost, David; Higgins, Andrew

2015-06-01

The incidence angle of a detonation wave is often assumed to weakly influence the terminal velocity of an explosively driven flyer. For explosives heavily loaded with dense additives, this may not be true due to differences in momentum and energy transfer between detonation products, additive particles, and the flyer. For tangential incidence the particles are first accelerated against the flyer via an expansion fan, whereas they are first accelerated by the detonation wave in the normal case. In the current study we evaluate the effect of normal versus tangential incidence on the acceleration of flyers by nitromethane heavily loaded with a variety of additives. Normal detonation was initiated via an explosively driven slapper. Flyer acceleration was measured with heterodyne laser interferometry (PDV). The influence of wave angle is evaluated by comparing the terminal velocity in the two cases (i.e., normal and grazing) for the heavily loaded mixtures. The decrement in flyer velocity correlated primarily with additive volume fraction and had a weak dependence on additive density or particle size. The Gurney energy of the heterogeneous explosive was observed to increase with flyer mass, presumably due to the timescale over which impinging particles could transfer momentum.
Simultaneous manipulation and observation of multiple ro-vibrational eigenstates in solid para-hydrogen.

PubMed

Katsuki, Hiroyuki; Ohmori, Kenji

2016-09-28

We have experimentally performed the coherent control of delocalized ro-vibrational wave packets (RVWs) of solid para-hydrogen (p-H 2 ) by the wave packet interferometry (WPI) combined with coherent anti-Stokes Raman scattering (CARS). RVWs of solid p-H 2 are delocalized in the crystal, and the wave function with wave vector k ∼ 0 is selectively excited via the stimulated Raman process. We have excited the RVW twice by a pair of femtosecond laser pulses with delay controlled by a stabilized Michelson interferometer. Using a broad-band laser pulse, multiple ro-vibrational states can be excited simultaneously. We have observed the time-dependent Ramsey fringe spectra as a function of the inter-pulse delay by a spectrally resolved CARS technique using a narrow-band probe pulse, resolving the different intermediate states. Due to the different fringe oscillation periods among those intermediate states, we can manipulate their amplitude ratio by tuning the inter-pulse delay on the sub-femtosecond time scale. The state-selective manipulation and detection of the CARS signal combined with the WPI is a general and efficient protocol for the control of the interference of multiple quantum states in various quantum systems.
Emission of sound from the mammalian inner ear

NASA Astrophysics Data System (ADS)

Reichenbach, Tobias; Stefanovic, Aleksandra; Nin, Fumiaki; Hudspeth, A. J.

2013-03-01

The mammalian inner ear, or cochlea, not only acts as a detector of sound but can also produce tones itself. These otoacoustic emissions are a striking manifestation of the mechanical active process that sensitizes the cochlea and sharpens its frequency discrimination. It remains uncertain how these signals propagate back to the middle ear, from which they are emitted as sound. Although reverse propagation might occur through waves on the cochlear basilar membrane, experiments suggest the existence of a second component in otoacoustic emissions. We have combined theoretical and experimental studies to show that mechanical signals can also be transmitted by waves on Reissner's membrane, a second elastic structure within the cochea. We have developed a theoretical description of wave propagation on the parallel Reissner's and basilar membranes and its role in the emission of distortion products. By scanning laser interferometry we have measured traveling waves on Reissner's membrane in the gerbil, guinea pig, and chinchilla. The results accord with the theory and thus support a role for Reissner's membrane in otoacoustic emission. T. R. holds a Career Award at the Scientific Interface from the Burroughs Wellcome Fund; A. J. H. is an Investigator of Howard Hughes Medical Institute.
Time-Lapse Monitoring with 4D Seismic Coda Waves in Active, Passive and Ambient Noise Data

NASA Astrophysics Data System (ADS)

Lumley, D. E.; Kamei, R.; Saygin, E.; Shragge, J. C.

2017-12-01

The Earth's subsurface is continuously changing, due to temporal variations in fluid flow, stress, temperature, geomechanics and geochemistry, for example. These physical changes occur at broad tectonic and earthquake scales, and also at very detailed near-surface and reservoir scales. Changes in the physical states of the earth cause time-varying changes in the physical properties of rocks and fluids, which can be monitored with natural or manmade seismic waves. Time-lapse (4D) seismic monitoring is important for applications related to natural and induced seismicity, hydrocarbon and groundwater reservoir depletion, CO2 sequestration etc. An exciting new research area involves moving beyond traditional methods in order to use the full complex time-lapse scattered wavefield (4D coda waves) for both manmade active-source 3D/4D seismic data, and also to use continuous recordings of natural-source passive seismic data, especially (micro) earthquakes and ocean ambient noise. This research involves full wave-equation approaches including waveform inversion (FWI), interferometry, Large N sensor arrays, "big data" information theory, and high performance supercomputing (HPC). I will present high-level concepts and recent data results that are quite spectacular and highly encouraging.

Shock compression and release of a-axis magnesium single crystals: Anisotropy and time dependent inelastic response

DOE PAGES

Renganathan, P.; Winey, J. M.; Gupta, Y. M.

2017-01-19

Here, to gain insight into inelastic deformation mechanisms for shocked hexagonal close-packed (hcp) metals, particularly the role of crystal anisotropy, magnesium (Mg) single crystals were subjected to shock compression and release along the a-axis to 3.0 and 4.8 GPa elastic impact stresses. Wave profiles measured at several thicknesses, using laser interferometry, show a sharply peaked elastic wave followed by the plastic wave. Additionally, a smooth and featureless release wave is observed following peak compression. When compared to wave profiles measured previously for c-axis Mg, the elastic wave amplitudes for a-axis Mg are lower for the same propagation distance, and less attenuation of elastic wave amplitude is observed for a given peak stress. The featureless release wave for a-axis Mg is in marked contrast to the structured features observed for c-axis unloading. Numerical simulations, using a time-dependent anisotropic modeling framework, showed that the wave profiles calculated using prismatic slip or (10more » $$\\bar{1}$$2) twinning, individually, do not match the measured compression profiles for a-axis Mg. However, a combination of slip and twinning provides a good overall match to the measured compression profiles. In contrast to compression,prismatic slip alone provides a reasonable match to the measured release wave profiles; (10$$\\bar{1}$$2) twinning due to its uni-directionality is not activated during release. The experimental results and wave profile simulations for a-axis Mg presented here are quite different from the previously published c-axis results, demonstrating the important role of crystal anisotropy on the time-dependent inelastic deformation of Mg single crystals under shock compression and release.« less
Shock compression and release of a-axis magnesium single crystals: Anisotropy and time dependent inelastic response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Renganathan, P.; Winey, J. M.; Gupta, Y. M.

Here, to gain insight into inelastic deformation mechanisms for shocked hexagonal close-packed (hcp) metals, particularly the role of crystal anisotropy, magnesium (Mg) single crystals were subjected to shock compression and release along the a-axis to 3.0 and 4.8 GPa elastic impact stresses. Wave profiles measured at several thicknesses, using laser interferometry, show a sharply peaked elastic wave followed by the plastic wave. Additionally, a smooth and featureless release wave is observed following peak compression. When compared to wave profiles measured previously for c-axis Mg, the elastic wave amplitudes for a-axis Mg are lower for the same propagation distance, and less attenuation of elastic wave amplitude is observed for a given peak stress. The featureless release wave for a-axis Mg is in marked contrast to the structured features observed for c-axis unloading. Numerical simulations, using a time-dependent anisotropic modeling framework, showed that the wave profiles calculated using prismatic slip or (10more » $$\\bar{1}$$2) twinning, individually, do not match the measured compression profiles for a-axis Mg. However, a combination of slip and twinning provides a good overall match to the measured compression profiles. In contrast to compression,prismatic slip alone provides a reasonable match to the measured release wave profiles; (10$$\\bar{1}$$2) twinning due to its uni-directionality is not activated during release. The experimental results and wave profile simulations for a-axis Mg presented here are quite different from the previously published c-axis results, demonstrating the important role of crystal anisotropy on the time-dependent inelastic deformation of Mg single crystals under shock compression and release.« less
Combined Determination of Elastic Properties and Structure of Coesite under Simulated Mantle Conditions

NASA Astrophysics Data System (ADS)

Mueller, H. J.; Schilling, F. R.; Lauterjung, J.; Lathe, C.

2001-12-01

The high pressure SiO2-polymorph coesite seems to be an important mineral in the subduction process including crustal material (Chopin, 1984; Schreyer, 1995). The quartz to coesite transition is thus of fundamental importance to understand the processes within a subducting crust. Furthermore, the nature of the quartz to coesite transition is discussed controversially, because high pressure XRD-studies suggest an intermediate phase during the transformation process (Zinn et al., 1997). For the combined determination of elastic properties and structure a cubic multi-anvil high pressure apparatus (MAX80) was used. For the maximum sample volume of 20 mm3 the pressure limit is about 7GPa. The pressure is measured by use of NaCl as an internal pressure marker with calibrated PVT-data. The maximum temperature of about 2,000K is generated by an internal graphite heater and controlled by a thermocouple. The synchrotron beam (100x100 microns) is guided by a collimator through the sample between the anvils. For energy-dispersive X-ray diffraction, a Ge-solid state detector analyses the diffracted white beam at a fixed angle. The compressional and shear wave velocities were determined simultaneously by ultrasonic interferometry inside MAX80. Two of the six anvils are equipped with overtone polished lithium niobate transducers at their rear side, outside the volume under pressure, for generation and detection of ultrasonic waves between 10 and 60 MHz. Different buffer - reflector combinations and transducer arrangements were used to optimize the critical interference between both sample echoes. Therefore MAX80 is equipped for asymmetrical and symmetrical interferometric set-ups, i.e. compressional and shear waves are generated from the same or from two anvils, opposite to each other. We used for our transient measurements 3 natural fine-grained quartzites from Turkey and Germany. As a first step the pressure was increased gradually up to 4GPa at ambient temperature. At each pressure Vp and Vs was measured by ultrasonic interferometry. After reaching a given pressure, temperature was increased. At 4.5GPa and 800\\deg C the phase transition to coesite took place in less than 2 minutes. The fast kinetic of transformation was observed by synchrotron radiation. The compressional wave velocity increased by 30% and the shear wave velocity by 10% during the phase transition. The kinetic of the transition was varied by choosing different pressure and temperature conditions. The transformation with lower kinetic was studied in detail by XRD and ultrasonic interferometry. At 4.2 GPa the transformation could not be observed even above 950\\deg C. At 4.5 GPa and 750\\deg C the transition stopped at about 50% transformation, but transforms complete while increasing temperature to 800\\deg C. After the phase transition monitored by X-ray scattering the sample was quenched and Vp and Vs of coesite was measured at ambient temperatures up to the maximum pressure. Small differences in grain size, shape and in minor graphite contents did not change systematically the PT-conditions and kinetics. In addition to the kinetic and change of elastic properties the pressure and temperature derivatives of elastic properties of coesite will be presented.\\Chopin, C., Contr. Min. Petrol., 86 (1984), 107-118\\Schreyer, W., J. Geophys. Res., 100 (1995), 8,353-8,366\\Zinn P., Lauterjung J., Wirth R. & Hinze E. Zeitschrift für Kristallographie, 212 (1997), 691-698.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandal, A.; Gupta, Y. M.

To understand the elastic-plastic deformation response of shock-compressed molybdenum (Mo) – a body-centered cubic (BCC) metal, single crystal samples were shocked along the [100] crystallographic orientation to an elastic impact stress of 12.5 GPa. Elastic-plastic wave profiles, measured at different propagation distances ranging between ~0.23 to 2.31 mm using laser interferometry, showed a time-dependent material response. Within experimental scatter, the measured elastic wave amplitudes were nearly constant over the propagation distances examined. These data point to a large and rapid elastic wave attenuation near the impact surface, before reaching a threshold value (elastic limit) of ~3.6 GPa. Numerical simulations ofmore » the measured wave profiles, performed using a dislocation-based continuum model, suggested that {110}<111> and/or {112}<111> slip systems are operative under shock loading. In contrast to shocked metal single crystals with close-packed structures, the measured wave profiles in Mo single crystals could not be explained in terms of dislocation multiplication alone. A dislocation generation mechanism, operative for shear stresses larger than that at the elastic limit, was required to model the rapid elastic wave attenuation and to provide a good overall match to the measured wave profiles. However, the physical basis for this mechanism was not established for the high-purity single crystal samples used in this study. As a result, the numerical simulations also suggested that Mo single crystals do not work harden significantly under shock loading in contrast to the behavior observed under quasi-static loading.« less
Analysis of the Capability and Limitations of Relativistic Gravity Measurements Using Radio Astronomy Methods

NASA Technical Reports Server (NTRS)

Shapiro, I. I.; Counselman, C. C., III

1975-01-01

The uses of radar observations of planets and very-long-baseline radio interferometric observations of extragalactic objects to test theories of gravitation are described in detail with special emphasis on sources of error. The accuracy achievable in these tests with data already obtained, can be summarized in terms of: retardation of signal propagation (radar), deflection of radio waves (interferometry), advance of planetary perihelia (radar), gravitational quadrupole moment of sun (radar), and time variation of gravitational constant (radar). The analyses completed to date have yielded no significant disagreement with the predictions of general relativity.
Arm Locking for the Laser Interferometer Space Antenna

NASA Technical Reports Server (NTRS)

Maghami, P. G.; Thorpe, J. I.; Livas, J.

2009-01-01

The Laser Interferometer Space Antenna (LISA) mission is a planned gravitational wave detector consisting of three spacecraft in heliocentric orbit. Laser interferometry is used to measure distance fluctuations between test masses aboard each spacecraft to the picometer level over a 5 million kilometer separation. Laser frequency fluctuations must be suppressed in order to meet the measurement requirements. Arm-locking, a technique that uses the constellation of spacecraft as a frequency reference, is a proposed method for stabilizing the laser frequency. We consider the problem of arm-locking using classical optimal control theory and find that our designs satisfy the LISA requirements.
Quantitative polarized light microscopy using spectral multiplexing interferometry.

PubMed

Li, Chengshuai; Zhu, Yizheng

2015-06-01

We propose an interferometric spectral multiplexing method for measuring birefringent specimens with simple configuration and high sensitivity. The retardation and orientation of sample birefringence are simultaneously encoded onto two spectral carrier waves, generated interferometrically by a birefringent crystal through polarization mixing. A single interference spectrum hence contains sufficient information for birefringence determination, eliminating the need for mechanical rotation or electrical modulation. The technique is analyzed theoretically and validated experimentally on cellulose film. System simplicity permits the possibility of mitigating system birefringence background. Further analysis demonstrates the technique's exquisite sensitivity as high as ∼20 pm for retardation measurement.
Simultaneous measurements of density field and wavefront distortions in high speed flows

NASA Astrophysics Data System (ADS)

George, Jacob; Jenkins, Thomas; Trolinger, James; Hess, Cecil; Buckner, Benjamin

2017-09-01

This paper presents results from simultaneous measurements of fluid density and the resulting wavefront distortions in a sonic underexpanded jet. The density measurements were carried out using Rayleigh scattering, and the optical distortions were measured using a wavefront sensor based on phase shifting interferometry. The measurements represent a preliminary step toward relating wavefront distortions to a specific flow structure. The measured density field is used to compute the phase distortions using a wave propagation model based on a geometric-optics approximation, and the computed phase map shows moderate agreement with that obtained using the wavefront sensor.
A review of recent work in sub-nanometre displacement measurement using optical and X-ray interferometry.

PubMed

Peggs, G N; Yacoot, A

2002-05-15

This paper reviews recent work in the field of displacement measurement using optical and X-ray interferometry at the sub-nanometre level of accuracy. The major sources of uncertainty in optical interferometry are discussed and a selection of recent designs of ultra-precise, optical-interferometer-based, displacement measuring transducers presented. The use of X-ray interferometry and its combination with optical interferometry is discussed.
Bibliography of spatial interferometry in optical astronomy

NASA Technical Reports Server (NTRS)

Gezari, Daniel Y.; Roddier, Francois; Roddier, Claude

1990-01-01

The Bibliography of Spatial Interferometry in Optical Astronomy is a guide to the published literature in applications of spatial interferometry techniques to astronomical observations, theory and instrumentation at visible and infrared wavelengths. The key words spatial and optical define the scope of this discipline, distinguishing it from spatial interferometry at radio wavelengths, interferometry in the frequency domain applied to spectroscopy, or more general electro-optics theoretical and laboratory research. The main bibliography is a listing of all technical articles published in the international scientific literature and presented at the major international meetings and workshops attended by the spatial interferometry community. Section B summarizes publications dealing with the basic theoretical concepts and algorithms proposed and applied to optical spatial interferometry and imaging through a turbulent atmosphere. The section on experimental techniques is divided into twelve categories, representing the most clearly identified major areas of experimental research work. Section D, Observations, identifies publications dealing specifically with observations of astronomical sources, in which optical spatial interferometry techniques have been applied.
Speckle interferometry of asteroids

NASA Technical Reports Server (NTRS)

Drummond, Jack

1988-01-01

This final report for NASA Contract NAGw-867 consists of abstracts of the first three papers in a series of four appearing in Icarus that were funded by the preceding contract NAGw-224: (1) Speckle Interferometry of Asteroids I. 433 Eros; (2) Speckle Interferometry of Asteroids II. 532 Herculina; (3) Speckle Interferometry of Asteroids III. 511 Davida and its Photometry; and the fourth abstract attributed to NAGw-867, (4) Speckle Interferometry of Asteroids IV. Reconstructed images of 4 Vesta; and a review of the results from the asteroid interferometry program at Steward Observatory prepared for the Asteroids II book, (5) Speckle Interferometry of Asteroids. Two papers on asteroids, indirectly related to speckle interferometry, were written in part under NAGw-867. One is in press and its abstract is included here: Photometric Geodesy of Main-Belt Asteroids. II. Analysis of Lightcurves for Poles, Periods and Shapes; and the other paper, Triaxial Ellipsoid Dimensions and Rotational Pole of 2 Pallas from Two Stellar Occultations, is included in full.
Dual-reference digital holographic interferometry for analyzing high-density gradients in fluid mechanics.

PubMed

Desse, Jean-Michel; Olchewsky, François

2018-04-15

This Letter proposes a dual-reference digital holographic interferometer for analyzing the high refractive index encountered in transonic and supersonic flows. For that, a Wollaston prism is inserted in the reference arm in order to simultaneously generate two orthogonally polarized reference waves. As a consequence, recorded interferograms contain two crossed and perpendicular interference patterns that give two orders fully separated in the Fourier spectrum. It is then possible to analyze a transparent object regardless of the orientation of the refractive index gradient using the two phase maps reconstructed with each of the two first interference orders. Fusion of the phase maps yields a single phase map in which the phase singularities are removed. Experimental results demonstrate the suitability of the proposed approach for analyzing shock waves in the unsteady wake flow around a circular cylinder at Mach 0.75.
A self-interfering clock as a “which path” witness

NASA Astrophysics Data System (ADS)

Margalit, Yair; Zhou, Zhifan; Machluf, Shimon; Rohrlich, Daniel; Japha, Yonathan; Folman, Ron

2015-09-01

In Einstein’s general theory of relativity, time depends locally on gravity; in standard quantum theory, time is global—all clocks “tick” uniformly. We demonstrate a new tool for investigating time in the overlap of these two theories: a self-interfering clock, comprising two atomic spin states. We prepare the clock in a spatial superposition of quantum wave packets, which evolve coherently along two paths into a stable interference pattern. If we make the clock wave packets “tick” at different rates, to simulate a gravitational time lag, the clock time along each path yields “which path” information, degrading the pattern’s visibility. In contrast, in standard interferometry, time cannot yield “which path” information. This proof-of-principle experiment may have implications for the study of time and general relativity and their impact on fundamental effects such as decoherence and the emergence of a classical world.
Physical properties of hydrated tissue determined by surface interferometry of laser-induced thermoelastic deformation

NASA Astrophysics Data System (ADS)

Dark, Marta L.; Perelman, Lev T.; Itzkan, Irving; Schaffer, Jonathan L.; Feld, Michael S.

2000-02-01

Knee meniscus is a hydrated tissue; it is a fibrocartilage of the knee joint composed primarily of water. We present results of interferometric surface monitoring by which we measure physical properties of human knee meniscal cartilage. The physical response of biological tissue to a short laser pulse is primarily thermomechanical. When the pulse is shorter than characteristic times (thermal diffusion time and acoustic relaxation time) stresses build and propagate as acoustic waves in the tissue. The tissue responds to the laser-induced stress by thermoelastic expansion. Solving the thermoelastic wave equation numerically predicts the correct laser-induced expansion. By comparing theory with experimental data, we can obtain the longitudinal speed of sound, the effective optical penetration depth and the Grüneisen coefficient. This study yields information about the laser-tissue interaction and determines properties of the meniscus samples that could be used as diagnostic parameters.
A self-interfering clock as a "which path" witness.

PubMed

Margalit, Yair; Zhou, Zhifan; Machluf, Shimon; Rohrlich, Daniel; Japha, Yonathan; Folman, Ron

2015-09-11

In Einstein's general theory of relativity, time depends locally on gravity; in standard quantum theory, time is global-all clocks "tick" uniformly. We demonstrate a new tool for investigating time in the overlap of these two theories: a self-interfering clock, comprising two atomic spin states. We prepare the clock in a spatial superposition of quantum wave packets, which evolve coherently along two paths into a stable interference pattern. If we make the clock wave packets "tick" at different rates, to simulate a gravitational time lag, the clock time along each path yields "which path" information, degrading the pattern's visibility. In contrast, in standard interferometry, time cannot yield "which path" information. This proof-of-principle experiment may have implications for the study of time and general relativity and their impact on fundamental effects such as decoherence and the emergence of a classical world. Copyright © 2015, American Association for the Advancement of Science.
Holographic studies of shock waves within transonic fan rotors

NASA Technical Reports Server (NTRS)

Benser, W. A.; Bailey, E. E.; Gelder, T. F.

1974-01-01

NASA has funded two separate contracts to apply pulsed laser holographic interferometry to the detection of shock patterns in the outer span regions of high tip speed transonic rotors. The first holographic approach used ruby laser light reflected from a portion of the centerbody just ahead of the rotor. These holograms showed the bow wave patterns upstream of the rotor and the shock patterns just inside the blade row near the tip. The second holographic approach, on a different rotor, used light transmitted diagonally across the inlet annulus past the centerbody. This approach gave a more extensive view of the region bounded by the blade leading and trailing edges, by the part span shroud and by the blade tip. These holograms showed the passage shock emanating from the blade leading edge and a moderately strong conical shock originating at the intersection of the part span shroud leading edge and the blade suction surface.
Attosecond-resolved photoionization of chiral molecules.

PubMed

Beaulieu, S; Comby, A; Clergerie, A; Caillat, J; Descamps, D; Dudovich, N; Fabre, B; Géneaux, R; Légaré, F; Petit, S; Pons, B; Porat, G; Ruchon, T; Taïeb, R; Blanchet, V; Mairesse, Y

2017-12-08

Chiral light-matter interactions have been investigated for two centuries, leading to the discovery of many chiroptical processes used for discrimination of enantiomers. Whereas most chiroptical effects result from a response of bound electrons, photoionization can produce much stronger chiral signals that manifest as asymmetries in the angular distribution of the photoelectrons along the light-propagation axis. We implemented self-referenced attosecond photoelectron interferometry to measure the temporal profile of the forward and backward electron wave packets emitted upon photoionization of camphor by circularly polarized laser pulses. We measured a delay between electrons ejected forward and backward, which depends on the ejection angle and reaches 24 attoseconds. The asymmetric temporal shape of electron wave packets emitted through an autoionizing state further reveals the chiral character of strongly correlated electronic dynamics. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Modeling of Distributed Sensing of Elastic Waves by Fiber-Optic Interferometry

PubMed Central

Agbodjan Prince, Just; Kohl, Franz; Sauter, Thilo

2016-01-01

This paper deals with the transduction of strain accompanying elastic waves in solids by firmly attached optical fibers. Stretching sections of optical fibers changes the time required by guided light to pass such sections. Exploiting interferometric techniques, highly sensitive fiber-optic strain transducers are feasible based on this fiber-intrinsic effect. The impact on the actual strain conversion of the fiber segment’s shape and size, as well as its inclination to the elastic wavefront is studied. FEM analyses show that severe distortions of the interferometric response occur when the attached fiber length spans a noticeable fraction of the elastic wavelength. Analytical models of strain transduction are presented for typical transducer shapes. They are used to compute input-output relationships for the transduction of narrow-band strain pulses as a function of the mechanical wavelength. The described approach applies to many transducers depending on the distributed interaction with the investigated object. PMID:27608021
Modeling of Distributed Sensing of Elastic Waves by Fiber-Optic Interferometry.

PubMed

Agbodjan Prince, Just; Kohl, Franz; Sauter, Thilo

2016-09-06

This paper deals with the transduction of strain accompanying elastic waves in solids by firmly attached optical fibers. Stretching sections of optical fibers changes the time required by guided light to pass such sections. Exploiting interferometric techniques, highly sensitive fiber-optic strain transducers are feasible based on this fiber-intrinsic effect. The impact on the actual strain conversion of the fiber segment's shape and size, as well as its inclination to the elastic wavefront is studied. FEM analyses show that severe distortions of the interferometric response occur when the attached fiber length spans a noticeable fraction of the elastic wavelength. Analytical models of strain transduction are presented for typical transducer shapes. They are used to compute input-output relationships for the transduction of narrow-band strain pulses as a function of the mechanical wavelength. The described approach applies to many transducers depending on the distributed interaction with the investigated object.
Testing the quantum superposition principle: matter waves and beyond

NASA Astrophysics Data System (ADS)

Ulbricht, Hendrik

2015-05-01

New technological developments allow to explore the quantum properties of very complex systems, bringing the question of whether also macroscopic systems share such features, within experimental reach. The interest in this question is increased by the fact that, on the theory side, many suggest that the quantum superposition principle is not exact, departures from it being the larger, the more macroscopic the system. Testing the superposition principle intrinsically also means to test suggested extensions of quantum theory, so-called collapse models. We will report on three new proposals to experimentally test the superposition principle with nanoparticle interferometry, optomechanical devices and by spectroscopic experiments in the frequency domain. We will also report on the status of optical levitation and cooling experiments with nanoparticles in our labs, towards an Earth bound matter-wave interferometer to test the superposition principle for a particle mass of one million amu (atomic mass unit).

Strain measurement in the wavy-ply region of an externally pressurized cross-ply composite ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gascoigne, H.E.; Abdallah, M.G.

1996-07-01

Ply-level strains are determined in the cross-section of an externally pressurized cross-ply (3:1 circumferential to axial fiber ratio) graphite-epoxy ring containing an isolated circumferential wavy region. A special test fixture was used which permitted measuring orthogonal displacement components in the wavy area using moire interferometry as the pressure was increased. Strain components were determined at selected locations in the wavy area up to approximately90% of failure pressure. The study shows: (1) large interlaminar shear strains, which are non-existent in the perfect ring, are present near the wave inflection points; (2) the wavy plies generate increased interlaminar normal compressive strains inmore » both circumferential and axial plies along a radial line coinciding with maximum wave amplitude; and (3) nonlinear strain response begins at approximately 60% of failure pressure.« less
Far-field interference of a neutron white beam and the applications to noninvasive phase-contrast imaging

NASA Astrophysics Data System (ADS)

Pushin, D. A.; Sarenac, D.; Hussey, D. S.; Miao, H.; Arif, M.; Cory, D. G.; Huber, M. G.; Jacobson, D. L.; LaManna, J. M.; Parker, J. D.; Shinohara, T.; Ueno, W.; Wen, H.

2017-04-01

The phenomenon of interference plays a crucial role in the field of precision measurement science. Wave-particle duality has expanded the well-known interference effects of electromagnetic waves to massive particles. The majority of the wave-particle interference experiments require a near monochromatic beam which limits its applications due to the resulting low intensity. Here we demonstrate white beam interference in the far-field regime using a two-phase-grating neutron interferometer and its application to phase-contrast imaging. The functionality of this interferometer is based on the universal moiré effect that allows us to improve upon the standard Lau setup. Interference fringes were observed with monochromatic and polychromatic neutron beams for both continuous and pulsed beams. Far-field neutron interferometry allows for the full utilization of intense neutron sources for precision measurements of gradient fields. It also overcomes the alignment, stability, and fabrication challenges associated with the more familiar perfect-crystal neutron interferometer, as well as avoids the loss of intensity due to the absorption analyzer grating requirement in Talbot-Lau interferometer.
Spatiotemporal behavior and nonlinear dynamics in a phase conjugate resonator

NASA Technical Reports Server (NTRS)

Liu, Siuying Raymond

1993-01-01

The work described can be divided into two parts. The first part is an investigation of the transient behavior and stability property of a phase conjugate resonator (PCR) below threshold. The second part is an experimental and theoretical study of the PCR's spatiotemporal dynamics above threshold. The time-dependent coupled wave equations for four-wave mixing (FWM) in a photorefractive crystal, with two distinct interaction regions caused by feedback from an ordinary mirror, was used to model the transient dynamics of a PCR below threshold. The conditions for self-oscillation were determined and the solutions were used to define the PCR's transfer function and analyze its stability. Experimental results for the buildup and decay times confirmed qualitatively the predicted behavior. Experiments were carried out above threshold to study the spatiotemporal dynamics of the PCR as a function of Pragg detuning and the resonator's Fresnel number. The existence of optical vortices in the wavefront were identified by optical interferometry. It was possible to describe the transverse dynamics and the spatiotemporal instabilities by modeling the three-dimensional-coupled wave equations in photorefractive FWM using a truncated modal expansion approach.
Elastic Anomaly and Polyamorphic Transition in (La, Ce)-based Bulk Metallic Glass under Pressure

DOE PAGES

Qi, Xintong; Zou, Yongtao; Wang, Xuebing; ...

2017-04-07

In this paper, we discovered that in association with the polyamorphism of La 32Ce 32Al 16Ni 5Cu 15 bulk metallic glass, the acoustic velocities, measured up to 12.3 GPa using ultrasonic interferometry, exhibit velocity minima at 1.8 GPa for P wave and 3.2 GPa for S wave. The low and high density amorphous states are distinguished by their distinct pressure derivatives of the bulk and shear moduli. The elasticity, permanent densification, and polyamorphic transition are interpreted by the topological rearrangement of solute-centered clusters in medium-range order (MRO) mediated by the 4f electron delocalization of Ce under pressure. The precisely measuredmore » acoustic wave travel times which were used to derive the velocities and densities provided unprecedented data to document the evolution of the bulk and shear elastic moduli associated with a polyamorphic transition in La 32Ce 32Al 16Ni 5Cu 15 bulk metallic glass and can shed new light on the mechanisms of polyamorphism and structural evolution in metallic glasses under pressure.« less
Study of transmission line attenuation in broad band millimeter wave frequency range.

PubMed

Pandya, Hitesh Kumar B; Austin, M E; Ellis, R F

2013-10-01

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.
DSMC simulations of shock tube experiments for the dissociation rate of nitrogen

NASA Astrophysics Data System (ADS)

Bird, G. A.

2012-11-01

The DSMC method has been used to simulate the flow associated with several experiments that led to predictions of the dissociation rate in nitrogen. One involved optical interferometry to determine the density behind strong shock wave and the other involved the measurement of the shock tube end-wall pressure after the reflection of a similar shock wave. DSMC calculations for the un-reflected shock wave were made with the older TCE model that converts rate coefficients to reaction cross-sections, with the newer Q-K model that predicts the rates and with a set of reaction cross-sections for nitrogen dissociation from QCT calculations. A comparison of the resulting density profiles with the measured profile provides a test of the validity of the DSMC chemistry models. The DSMC reaction rates were sampled directly in the DSMC calculation, both far downstream where the flow is in equilibrium and in the non-equilibrium region immediately behind the shock. This permits a critical evaluation of data reduction procedures that were employed to deduce the dissociation rate from the measured quantities.
Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 GPa and 1073 K

NASA Astrophysics Data System (ADS)

Chen, Ting; Liebermann, Robert C.; Zou, Yongtao; Li, Ying; Qi, Xintong; Li, Baosheng

2017-08-01

The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 GPa and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach 34% and 45% for P and S wave velocities, respectively, and 64% and 75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences on silica, d(lnVP)/d(SiO2) = 0.38 (wt %)-1 and d(lnVS)/d(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.
Tracking silica in Earth's upper mantle using new sound velocity data for coesite to 5.8 GPa and 1073 K: Tracking Silica in Earth's Upper Mantle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ting; Liebermann, Robert C.; Zou, Yongtao

The compressional and shear wave velocities for coesite have been measured simultaneously up to 5.8 GPa and 1073 K by ultrasonic interferometry for the first time. The shear wave velocity decreases with pressure along all isotherms. The resulting contrasts between coesite and stishovite reach ~34% and ~45% for P and S wave velocities, respectively, and ~64% and ~75% for their impedance at mantle conditions. The large velocity and impedance contrasts across coesite-stishovite transition imply that to generate the velocity and impedance contrasts observed at the X-discontinuity, only a small amount of silica would be required. The velocity jump dependences onmore » silica, d(lnVP)/d(SiO2) = 0.38 (wt %)-1 and d(lnVS)/d(SiO2) = 0.52 (wt %)-1, are utilized to place constraints on the amount of silica in the upper mantle and provide a geophysical approach to track mantle eclogite materials and ancient subducted oceanic slabs.« less
Retrieving the axial position of fluorescent light emitting spots by shearing interferometry

NASA Astrophysics Data System (ADS)

Schindler, Johannes; Schau, Philipp; Brodhag, Nicole; Frenner, Karsten; Osten, Wolfgang

2016-12-01

A method for the depth-resolved detection of fluorescent radiation based on imaging of an interference pattern of two intersecting beams and shearing interferometry is presented. The illumination setup provides the local addressing of the excitation of fluorescence and a coarse confinement of the excitation volume in axial and lateral directions. The reconstruction of the depth relies on the measurement of the phase of the fluorescent wave fronts. Their curvature is directly related to the distance of a source to the focus of the imaging system. Access to the phase information is enabled by a lateral shearing interferometer based on a Michelson setup. This allows the evaluation of interference signals even for spatially and temporally incoherent light such as emitted by fluorophors. An analytical signal model is presented and the relations for obtaining the depth information are derived. Measurements of reference samples with different concentrations and spatial distributions of fluorophors and scatterers prove the experimental feasibility of the method. In a setup optimized for flexibility and operating in the visible range, sufficiently large interference signals are recorded for scatterers placed in depths in the range of hundred micrometers below the surface in a material with scattering properties comparable to dental enamel.
Optical bench development for LISA

NASA Astrophysics Data System (ADS)

d'Arcio, L.; Bogenstahl, J.; Dehne, M.; Diekmann, C.; Fitzsimons, E. D.; Fleddermann, R.; Granova, E.; Heinzel, G.; Hogenhuis, H.; Killow, C. J.; Perreur-Lloyd, M.; Pijnenburg, J.; Robertson, D. I.; Shoda, A.; Sohmer, A.; Taylor, A.; Tröbs, M.; Wanner, G.; Ward, H.; Weise, D.

2017-11-01

For observation of gravitational waves at frequencies between 30 μHz and 1 Hz, the LISA mission will be implemented in a triangular constellation of three identical spacecraft, which are mutually linked by laser interferometry in an active transponder scheme over a 5 million kilometer arm length. On the end point of each laser link, remote and local beam metrology with respect to inertial proof masses inside the spacecraft is realized by the LISA Optical Bench. It implements further- more various ancillary functions such as point-ahead correction, acquisition sensing, transmit beam conditioning, and laser redundancy switching. A comprehensive design of the Optical Bench has been developed, which includes all of the above mentioned functions and at the same time ensures manufacturability on the basis of hydroxide catalysis bonding, an ultrastable integration technology already perfected in the context of LISA's technology demonstrator mission LISA Pathfinder. Essential elements of this design have been validated by dedicated pre-investigations. These include the demonstration of polarizing heterodyne interferometry at the required Picometer and Nanoradian performance levels, the investigation of potential non-reciprocal noise sources in the so-called backlink fiber, as well as the development of a laser redundancy switch breadboard.
Quantifying Nucleic Acid Ensembles with X-ray Scattering Interferometry.

PubMed

Shi, Xuesong; Bonilla, Steve; Herschlag, Daniel; Harbury, Pehr

2015-01-01

The conformational ensemble of a macromolecule is the complete description of the macromolecule's solution structures and can reveal important aspects of macromolecular folding, recognition, and function. However, most experimental approaches determine an average or predominant structure, or follow transitions between states that each can only be described by an average structure. Ensembles have been extremely difficult to experimentally characterize. We present the unique advantages and capabilities of a new biophysical technique, X-ray scattering interferometry (XSI), for probing and quantifying structural ensembles. XSI measures the interference of scattered waves from two heavy metal probes attached site specifically to a macromolecule. A Fourier transform of the interference pattern gives the fractional abundance of different probe separations directly representing the multiple conformation states populated by the macromolecule. These probe-probe distance distributions can then be used to define the structural ensemble of the macromolecule. XSI provides accurate, calibrated distance in a model-independent fashion with angstrom scale sensitivity in distances. XSI data can be compared in a straightforward manner to atomic coordinates determined experimentally or predicted by molecular dynamics simulations. We describe the conceptual framework for XSI and provide a detailed protocol for carrying out an XSI experiment. © 2015 Elsevier Inc. All rights reserved.
Retrieving the axial position of fluorescent light emitting spots by shearing interferometry.

PubMed

Schindler, Johannes; Schau, Philipp; Brodhag, Nicole; Frenner, Karsten; Osten, Wolfgang

2016-12-01

A method for the depth-resolved detection of fluorescent radiation based on imaging of an interference pattern of two intersecting beams and shearing interferometry is presented. The illumination setup provides the local addressing of the excitation of fluorescence and a coarse confinement of the excitation volume in axial and lateral directions. The reconstruction of the depth relies on the measurement of the phase of the fluorescent wave fronts. Their curvature is directly related to the distance of a source to the focus of the imaging system. Access to the phase information is enabled by a lateral shearing interferometer based on a Michelson setup. This allows the evaluation of interference signals even for spatially and temporally incoherent light such as emitted by fluorophors. An analytical signal model is presented and the relations for obtaining the depth information are derived. Measurements of reference samples with different concentrations and spatial distributions of fluorophors and scatterers prove the experimental feasibility of the method. In a setup optimized for flexibility and operating in the visible range, sufficiently large interference signals are recorded for scatterers placed in depths in the range of hundred micrometers below the surface in a material with scattering properties comparable to dental enamel.
Experimental and computational investigation of microwave interferometry (MI) for detonation front characterization

NASA Astrophysics Data System (ADS)

Mays, Owen; Tringe, Joe; Souers, Clark; Lauderbach, Lisa; Baluyot, Emer; Converse, Mark; Kane, Ron

2017-06-01

Microwave interferometry (MI) presents several advantages over more traditional existing shock and deflagration front diagnostics. Most importantly, it directly interrogates these fronts, instead of measuring the evolution of containment surfaces or explosive edges. Here we present the results of MI measurements on detonator-initiated cylinder tests, as well as on deflagration-to-detonation transition experiments, with emphasis on optimization of signal strength through coupling devices and through microwave-transparent windows. Full-wave electromagnetic field finite element simulations were employed to better understand microwave coupling into porous and near full theoretical maximum density (TMD) explosives. HMX and TATB-based explosives were investigated. Data was collected simultaneously at 26.5 GHz and 39 GHz, allowing for direct comparison of the front characteristics and providing insight into the dielectric properties of explosives at these high frequencies. MI measurements are compared against detonation velocity results from photonic Doppler velocimetry probes and high speed cameras, demonstrating the accuracy of the MI technique. Our results illustrate features of front propagation behavior that are difficult to observe with other techniques. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Estimation of vibration frequency of loudspeaker diaphragm by parallel phase-shifting digital holography

NASA Astrophysics Data System (ADS)

Kakue, T.; Endo, Y.; Shimobaba, T.; Ito, T.

2014-11-01

We report frequency estimation of loudspeaker diaphragm vibrating at high speed by parallel phase-shifting digital holography which is a technique of single-shot phase-shifting interferometry. This technique records multiple phaseshifted holograms required for phase-shifting interferometry by using space-division multiplexing. We constructed a parallel phase-shifting digital holography system consisting of a high-speed polarization-imaging camera. This camera has a micro-polarizer array which selects four linear polarization axes for 2 × 2 pixels. We set a loudspeaker as an object, and recorded vibration of diaphragm of the loudspeaker by the constructed system. By the constructed system, we demonstrated observation of vibration displacement of loudspeaker diaphragm. In this paper, we aim to estimate vibration frequency of the loudspeaker diaphragm by applying the experimental results to frequency analysis. Holograms consisting of 128 × 128 pixels were recorded at a frame rate of 262,500 frames per second by the camera. A sinusoidal wave was input to the loudspeaker via a phone connector. We observed displacement of the loudspeaker diaphragm vibrating by the system. We also succeeded in estimating vibration frequency of the loudspeaker diaphragm by applying frequency analysis to the experimental results.
Light and/or atomic beams to detect ultraweak gravitational effects

NASA Astrophysics Data System (ADS)

Tartaglia, Angelo; Belfi, Jacopo; Beverini, Nicolò; Di Virgilio, Angela; Ortolan, Antonello; Porzio, Alberto; Ruggiero, Matteo Luca

2014-06-01

We shall review the opportunities lent by ring lasers and atomic beams interferometry in order to reveal gravitomagnetic effects on Earth. Both techniques are based on the asymmetric propagation of waves in the gravitational field of a rotating mass; actually the times of flight for co- or counter-rotating closed paths turn out to be different. After discussing properties and limitations of the two approaches we shall describe the proposed GINGER experiment which is being developed for the Gran Sasso National Laboratories in Italy. The experimental apparatus will consist of a three-dimensional array of square rings, 6m × 6m, that is planned to reach a sensitivity in the order of 1prad/√Hertz or better. This sensitivity would be one order of magnitude better than the best existing ring, which is the G-ring in Wettzell, Bavaria, and would allow for the terrestrial detection of the Lense-Thirring effect and possibly of deviations from General Relativity. The possibility of using either the ring laser approach or atomic interferometry in a space mission will also be considered. The technology problems are under experimental study using both the German G-ring and the smaller G-Pisa ring, located at the Gran Sasso.
Uncovering by atomic force microscopy of an original circular structure at the yeast cell surface in response to heat shock.

PubMed

Pillet, Flavien; Lemonier, Stéphane; Schiavone, Marion; Formosa, Cécile; Martin-Yken, Hélène; Francois, Jean Marie; Dague, Etienne

2014-01-27

Atomic Force Microscopy (AFM) is a polyvalent tool that allows biological and mechanical studies of full living microorganisms, and therefore the comprehension of molecular mechanisms at the nanoscale level. By combining AFM with genetical and biochemical methods, we explored the biophysical response of the yeast Saccharomyces cerevisiae to a temperature stress from 30°C to 42°C during 1 h. We report for the first time the formation of an unprecedented circular structure at the cell surface that takes its origin at a single punctuate source and propagates in a concentric manner to reach a diameter of 2-3 μm at least, thus significantly greater than a bud scar. Concomitantly, the cell wall stiffness determined by the Young's Modulus of heat stressed cells increased two fold with a concurrent increase of chitin. This heat-induced circular structure was not found either in wsc1Δ or bck1Δ mutants that are defective in the CWI signaling pathway, nor in chs1Δ, chs3Δ and bni1Δ mutant cells, reported to be deficient in the proper budding process. It was also abolished in the presence of latrunculin A, a toxin known to destabilize actin cytoskeleton. Our results suggest that this singular morphological event occurring at the cell surface is due to a dysfunction in the budding machinery caused by the heat shock and that this phenomenon is under the control of the CWI pathway.
The Cell Wall Protein Ecm33 of Candida albicans is Involved in Chronological Life Span, Morphogenesis, Cell Wall Regeneration, Stress Tolerance, and Host-Cell Interaction.

PubMed

Gil-Bona, Ana; Reales-Calderon, Jose A; Parra-Giraldo, Claudia M; Martinez-Lopez, Raquel; Monteoliva, Lucia; Gil, Concha

2016-01-01

Ecm33 is a glycosylphosphatidylinositol-anchored protein in the human pathogen Candida albicans. This protein is known to be involved in fungal cell wall integrity (CWI) and is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis, but its function remains unknown. In this work, several phenotypic analyses of the C. albicans ecm33/ecm33 mutant (RML2U) were performed. We observed that RML2U displays the inability of protoplast to regenerate the cell wall, activation of the CWI pathway, hypersensitivity to temperature, osmotic and oxidative stresses and a shortened chronological lifespan. During the exponential and stationary culture phases, nuclear and actin staining revealed the possible arrest of the cell cycle in RML2U cells. Interestingly, a "veil growth," never previously described in C. albicans, was serendipitously observed under static stationary cells. The cells that formed this structure were also observed in cornmeal liquid cultures. These cells are giant, round cells, without DNA, and contain large vacuoles, similar to autophagic cells observed in other fungi. Furthermore, RML2U was phagocytozed more than the wild-type strain by macrophages at earlier time points, but the damage caused to the mouse cells was less than with the wild-type strain. Additionally, the percentage of RML2U apoptotic cells after interaction with macrophages was fewer than in the wild-type strain.
The Cell Wall Protein Ecm33 of Candida albicans is Involved in Chronological Life Span, Morphogenesis, Cell Wall Regeneration, Stress Tolerance, and Host–Cell Interaction

PubMed Central

Gil-Bona, Ana; Reales-Calderon, Jose A.; Parra-Giraldo, Claudia M.; Martinez-Lopez, Raquel; Monteoliva, Lucia; Gil, Concha

2016-01-01

Ecm33 is a glycosylphosphatidylinositol-anchored protein in the human pathogen Candida albicans. This protein is known to be involved in fungal cell wall integrity (CWI) and is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis, but its function remains unknown. In this work, several phenotypic analyses of the C. albicans ecm33/ecm33 mutant (RML2U) were performed. We observed that RML2U displays the inability of protoplast to regenerate the cell wall, activation of the CWI pathway, hypersensitivity to temperature, osmotic and oxidative stresses and a shortened chronological lifespan. During the exponential and stationary culture phases, nuclear and actin staining revealed the possible arrest of the cell cycle in RML2U cells. Interestingly, a “veil growth,” never previously described in C. albicans, was serendipitously observed under static stationary cells. The cells that formed this structure were also observed in cornmeal liquid cultures. These cells are giant, round cells, without DNA, and contain large vacuoles, similar to autophagic cells observed in other fungi. Furthermore, RML2U was phagocytozed more than the wild-type strain by macrophages at earlier time points, but the damage caused to the mouse cells was less than with the wild-type strain. Additionally, the percentage of RML2U apoptotic cells after interaction with macrophages was fewer than in the wild-type strain. PMID:26870022
Seismic Interferometry of Gulf of Mexico Basin Opening (GUMBO) Data: Extraction of Body and Surface Waves with a Mixed-Mode Array

NASA Astrophysics Data System (ADS)

Thangraj, J. S.; Quiros, D.; Pulliam, J.

2017-12-01

The Gulf of Mexico (GoM) is a relative small oceanic basin that formed by rifting between the continental blocks of North America and Yucatan in the Middle to Late Jurassic. Following the breakup, seafloor spreading continued until the Early Cretaceous. Since then, subsidence and sedimentation have shaped the GoM margin that we see today. To better understand the opening of the GoM, a long-offset (307 km) seismic refraction line was acquired in 2010. The transect was located on the northwest GoM margin, and consisted of several types of instruments. This mixed-mode array combined 31 ocean bottom seismographs (OBS), 412 high-frequency instruments (4.5 Hz geophones with RefTek 125A "Texan" digitizers) and 12 broadband stations. The R/V Iron Cat provided the airgun source used in the refraction experiment. The airgun generated 2028 shots in a period of 2.5 days which were recorded by the entire array. The airgun-generated seismic energy was clearly visible on the OBS recordings, however its amplitude was too low to be discerned on most of the onshore stations. In fact, this energy was only visible on Texan stations 1-50 (station 1 is located at the coast), extending 18 km inland, limiting the extend of the velocity model that can be obtained. Here, we apply seismic interferometry techniques to the 2.5 days of continuous data recorded by the Texan array with the goal of extending the spatial range for which the airgun-generated seismic energy can be observed. Preliminary results show that by treating the 2.5 days of continuously recorded airgun data as ambient noise, and applying time-domain cross-correlation, we can observe energy propagating 50 to 70 km inland with apparent velocities of 1800 - 2200 ms-1. These velocities agree with the compressional seismic velocity for the top 5 km of sediments under the GoM obtained from the OBS records, suggesting that we are observing compressional energy in the virtual source gathers (VSG). We also observe arrivals in the VSG that exhibit dispersive behavior, which we interpret to be Rayleigh waves. Current efforts are focused on extending the spatial range of the airgun-generated seismic energy further inland (> 70 km) by creating more VSG, to obtain a body wave velocity model along the transect. Similarly, we are inverting the Rayleigh waves in the VSG to obtain a shear wave velocity model.
Precision requirements and innovative manufacturing for ultrahigh precision laser interferometry of gravitational-wave astronomy

NASA Astrophysics Data System (ADS)

Ni, Wei-Tou; Han, Sen; Jin, Tao

2016-11-01

With the LIGO announcement of the first direct detection of gravitational waves (GWs), the GW Astronomy was formally ushered into our age. After one-hundred years of theoretical investigation and fifty years of experimental endeavor, this is a historical landmark not just for physics and astronomy, but also for industry and manufacturing. The challenge and opportunity for industry is precision and innovative manufacturing in large size - production of large and homogeneous optical components, optical diagnosis of large components, high reflectance dielectric coating on large mirrors, manufacturing of components for ultrahigh vacuum of large volume, manufacturing of high attenuating vibration isolation system, production of high-power high-stability single-frequency lasers, production of high-resolution positioning systems etc. In this talk, we address the requirements and methods to satisfy these requirements. Optical diagnosis of large optical components requires large phase-shifting interferometer; the 1.06 μm Phase Shifting Interferometer for testing LIGO optics and the recently built 24" phase-shifting Interferometer in Chengdu, China are examples. High quality mirrors are crucial for laser interferometric GW detection, so as for ring laser gyroscope, high precision laser stabilization via optical cavities, quantum optomechanics, cavity quantum electrodynamics and vacuum birefringence measurement. There are stringent requirements on the substrate materials and coating methods. For cryogenic GW interferometer, appropriate coating on sapphire or silicon are required for good thermal and homogeneity properties. Large ultrahigh vacuum components and high attenuating vibration system together with an efficient metrology system are required and will be addressed. For space interferometry, drag-free technology and weak-light manipulation technology are must. Drag-free technology is well-developed. Weak-light phase locking is demonstrated in the laboratories while weak-light manipulation technology still needs developments.

Monitoring Unstable Glaciers with Seismic Noise Interferometry

NASA Astrophysics Data System (ADS)

Preiswerk, L. E.; Walter, F.

2016-12-01

Gravity-driven glacier instabilities are a threat to human infrastructure in alpine terrain, and this hazard is likely to increase with future changes in climate. Seismometers have been used previously on hazardous glaciers to monitor the natural englacial seismicity. In some situations, an increase in "icequake" activity may indicate fracture growth and thus an imminent major break-off. However, without independent constraints on unstable volumes, such mere event counting is of little use. A promising new approach to monitor unstable masses in Alpine terrain is coda wave interferometry of ambient noise. While already established in the solid earth, application to glaciers is not straightforward, because the lack of inhomogeneities typically suppresses seismic coda waves in glacier ice. Only glaciers with pervasive crevasses provide enough scattering to generate long codas. This is requirement is likely met for highly dynamic unstable glaciers. Here, we report preliminary results from a temporary 5-station on-ice array of seismometers (corner frequencies: 1 Hz, array aperture: 500m) on Bisgletscher (Switzerland). The seismometers were deployed in shallow boreholes, directly above the unstable tongue of the glacier. In the frequency band 4-12 Hz, we find stable noise cross-correlations, which in principle allows monitoring on a subdaily scale. The origin and the source processes of the ambient noise in these frequencies are however uncertain. As a first step, we evaluate the stability of the sources in order to separate effects of changing source parameters from changes of englacial properties. Since icequakes occurring every few seconds may dominate the noise field, we compare their temporal and spatial occurrences with the cross-correlation functions (stability over time, the asymmetry between causal and acausal parts of the cross-correlation functions) as well as with results from beamforming to assess the influence of these transient events on the noise field.
Continuous monitoring of high-rise buildings using seismic interferometry

NASA Astrophysics Data System (ADS)

Mordret, A.; Sun, H.; Prieto, G. A.; Toksoz, M. N.; Buyukozturk, O.

2016-12-01

The linear seismic response of a building is commonly extracted from ambient vibration measurements. Seismic deconvolution interferometry performed on ambient vibration measurements can also be used to estimate the dynamic characteristics of a building, such as the velocity of shear-waves travelling inside the building as well as a damping parameter depending on the intrinsic attenuation of the building and the soil-structure coupling. The continuous nature of the ambient vibrations allows us to measure these parameters repeatedly and to observe their temporal variations. We used 2 weeks of ambient vibration recorded by 36 accelerometers installed in the Green Building on the Massachusetts Institute of Technology campus (Cambridge, MA) to continuously monitor the shear-wave speed and the attenuation factor of the building. Due to the low strain of the ambient vibrations, the observed changes are totally reversible. The relative velocity changes between a reference deconvolution function and the current deconvolution functions are measured with two different methods: 1) the Moving Window Cross-Spectral technique and 2) the stretching technique. Both methods show similar results. We show that measuring the stretching coefficient for the deconvolution functions filtered around the fundamental mode frequency is equivalent to measuring the wandering of the fundamental frequency in the raw ambient vibration data. By comparing these results with local weather parameters, we show that the relative air humidity is the factor dominating the relative seismic velocity variations in the Green Building, as well as the wandering of the fundamental mode. The one-day periodic variations are affected by both the temperature and the humidity. The attenuation factor, measured as the exponential decay of the fundamental mode waveforms, shows a more complex behaviour with respect to the weather measurements.
Acute Anxiety Predicts Components of the Cold Shock Response on Cold Water Immersion: Toward an Integrated Psychophysiological Model of Acute Cold Water Survival

PubMed Central

Barwood, Martin J.; Corbett, Jo; Massey, Heather; McMorris, Terry; Tipton, Mike; Wagstaff, Christopher R. D.

2018-01-01

Introduction: Drowning is a leading cause of accidental death. In cold-water, sudden skin cooling triggers the life-threatening cold shock response (CSR). The CSR comprises tachycardia, peripheral vasoconstriction, hypertension, inspiratory gasp, and hyperventilation with the hyperventilatory component inducing hypocapnia and increasing risk of aspirating water to the lungs. Some CSR components can be reduced by habituation (i.e., reduced response to stimulus of same magnitude) induced by 3–5 short cold-water immersions (CWI). However, high levels of acute anxiety, a plausible emotion on CWI: magnifies the CSR in unhabituated participants, reverses habituated components of the CSR and prevents/delays habituation when high levels of anxiety are experienced concurrent to immersions suggesting anxiety is integral to the CSR. Purpose: To examine the predictive relationship that prior ratings of acute anxiety have with the CSR. Secondly, to examine whether anxiety ratings correlated with components of the CSR during immersion before and after induction of habituation. Methods: Forty-eight unhabituated participants completed one (CON1) 7-min immersion in to cold water (15°C). Of that cohort, twenty-five completed four further CWIs that would ordinarily induce CSR habituation. They then completed two counter-balanced immersions where anxiety levels were increased (CWI-ANX) or were not manipulated (CON2). Acute anxiety and the cardiorespiratory responses (cardiac frequency [fc], respiratory frequency [fR], tidal volume [VT], minute ventilation [E]) were measured. Multiple regression was used to identify components of the CSR from the most life-threatening period of immersion (1st minute) predicted by the anxiety rating prior to immersion. Relationships between anxiety rating and CSR components during immersion were assessed by correlation. Results: Anxiety rating predicted the fc component of the CSR in unhabituated participants (CON1; p < 0.05, r = 0.536, r2= 0.190). After habituation immersions (i.e., cohort 2), anxiety rating predicted the fR component of the CSR when anxiety levels were lowered (CON2; p < 0.05, r = 0.566, r2= 0.320) but predicted the fc component of the CSR (p < 0.05, r = 0.518, r2= 0.197) when anxiety was increased suggesting different drivers of the CSR when anxiety levels were manipulated; correlation data supported these relationships. Discussion: Acute anxiety is integral to the CSR before and after habituation. We offer a new integrated model including neuroanatomical, perceptual and attentional components of the CSR to explain these data. PMID:29695988
Acute Anxiety Predicts Components of the Cold Shock Response on Cold Water Immersion: Toward an Integrated Psychophysiological Model of Acute Cold Water Survival.

PubMed

Barwood, Martin J; Corbett, Jo; Massey, Heather; McMorris, Terry; Tipton, Mike; Wagstaff, Christopher R D

2018-01-01

Introduction: Drowning is a leading cause of accidental death. In cold-water, sudden skin cooling triggers the life-threatening cold shock response (CSR). The CSR comprises tachycardia, peripheral vasoconstriction, hypertension, inspiratory gasp, and hyperventilation with the hyperventilatory component inducing hypocapnia and increasing risk of aspirating water to the lungs. Some CSR components can be reduced by habituation (i.e., reduced response to stimulus of same magnitude) induced by 3-5 short cold-water immersions (CWI). However, high levels of acute anxiety, a plausible emotion on CWI: magnifies the CSR in unhabituated participants, reverses habituated components of the CSR and prevents/delays habituation when high levels of anxiety are experienced concurrent to immersions suggesting anxiety is integral to the CSR. Purpose: To examine the predictive relationship that prior ratings of acute anxiety have with the CSR. Secondly, to examine whether anxiety ratings correlated with components of the CSR during immersion before and after induction of habituation. Methods: Forty-eight unhabituated participants completed one (CON1) 7-min immersion in to cold water (15°C). Of that cohort, twenty-five completed four further CWIs that would ordinarily induce CSR habituation. They then completed two counter-balanced immersions where anxiety levels were increased (CWI-ANX) or were not manipulated (CON2). Acute anxiety and the cardiorespiratory responses (cardiac frequency [ f c ], respiratory frequency [ f R ], tidal volume [ V T ], minute ventilation [ E ]) were measured. Multiple regression was used to identify components of the CSR from the most life-threatening period of immersion (1 st minute) predicted by the anxiety rating prior to immersion. Relationships between anxiety rating and CSR components during immersion were assessed by correlation. Results: Anxiety rating predicted the f c component of the CSR in unhabituated participants (CON1; p < 0.05, r = 0.536, r 2 = 0.190). After habituation immersions (i.e., cohort 2), anxiety rating predicted the f R component of the CSR when anxiety levels were lowered (CON2; p < 0.05, r = 0.566, r 2 = 0.320) but predicted the f c component of the CSR ( p < 0.05, r = 0.518, r 2 = 0.197) when anxiety was increased suggesting different drivers of the CSR when anxiety levels were manipulated; correlation data supported these relationships. Discussion: Acute anxiety is integral to the CSR before and after habituation. We offer a new integrated model including neuroanatomical, perceptual and attentional components of the CSR to explain these data.
Synthesis of the Ecohydrology of a Mexican Tropical Montane Cloud Forest and Implications of Land Use and Climate Change

NASA Astrophysics Data System (ADS)

Asbjornsen, H.; Alvarado-Barrientos, M. S.; Bruijnzeel, L. A.; Dawson, T. E.; Geissert, D.; Goldsmith, G. R.; Gomez-Cardenas, M.; Gomez-Tagle, A.; Gotsch, S. F.; Holwerda, F.; McDonnell, J. J.; Munoz Villers, L. E.; Tobon, C.

2013-05-01

Land use conversion and climate change threaten the hydrological services from tropical montane cloud forests (TMCFs), but knowledge about cloud forest ecohydrology and the effects of global change drivers is limited. Here, we present a synthesis of research that traced the hydrologic sources, fluxes and flowpaths under different land cover types degraded pasture, regenerating forest, mature forest, pine reforestation) in a seasonally dry TMCF in Veracruz, Mexico. We used hydrological (cloud water interception, CWI; streamflow) and ecophysiological measurements (transpiration, E; foliar uptake, FU) in combination with stable isotope techniques to elucidate to these ecohydrological processes. Results revealed that CWI was ≤2% of total annual rainfall due to low fog occurrence and wind speeds. Fog without rainfall reduced E by a factor of 4-5 relative to sunny conditions and by a factor of 2 relative to overcast conditions; the water 'gained' from fog suppression was ~80-100 mm year-1 relative to sunny conditions. At the canopy scale, FU resulted in the recovery of 9% of total E, suggesting a crucial role in alleviating water deficit; but not sufficient to offset the 17% water loss from nighttime E. Trees primarily utilized water from 30-50 cm soil depth, while water reaching the stream was derived from deep, 'old' water that was distinct from 'new' rainwater and plant water. Soils had high infiltration rates and water storage capacity, which contributed to the relatively low rainfall-runoff response, mainly generated from deep subsurface flowpaths. Conversion of mature forest to pasture or forest regeneration on former TMCF increased annual water yield by 600 mm and 300 mm, respectively, while planting pine on degraded pastures reduced water yield by 365 mm. Our results suggest that the ecophysiological effects of fog via suppressed E and FU have a greater impact on water yield than direct inputs from CWI in this TMCF. Rapid vertical rainfall percolation and recharge result in a largely groundwater driven system whereby streamflow dynamics is uncoupled from plant water uptake, and water storage and buffering capacity are exceptionally high. These factors, combined with the soil properties, resulted in reduced dry season flows due to land use conversion to pasture only being detected towards the end of the dry season. Projected lifting of the cloud base associated with regional climate change combined with declining rainfall may significantly alter ecohydrological functions of these TMCFs.
Novel Payload Architectures for LISA

NASA Astrophysics Data System (ADS)

Johann, Ulrich A.; Gath, Peter F.; Holota, Wolfgang; Schulte, Hans Reiner; Weise, Dennis

2006-11-01

As part of the current LISA Mission Formulation Study, and based on prior internal investigations, Astrium Germany has defined and preliminary assessed novel payload architectures, potentially reducing overall complexity and improving budgets and costs. A promising concept is characterized by a single active inertial sensor attached to a single optical bench and serving both adjacent interferometer arms via two rigidly connected off-axis telescopes. The in-plane triangular constellation ``breathing angle'' compensation is accomplished by common telescope in-field of view pointing actuation of the transmit/received beams line of sight. A dedicated actuation mechanism located on the optical bench is required in addition to the on bench actuators for differential pointing of the transmit and receive direction perpendicular to the constellation plane. Both actuators operate in a sinusoidal yearly period. A technical challenge is the actuation mechanism pointing jitter and the monitoring and calibration of the laser phase walk which occurs while changing the optical path inside the optical assembly during re-pointing. Calibration or monitoring of instrument internal phase effects e.g. by a laser metrology truss derived from the existing interferometry is required. The architecture exploits in full the two-step interferometry (strap down) concept, separating functionally inter spacecraft and intra-spacecraft interferometry (reference mass laser metrology degrees of freedom sensing). The single test mass is maintained as cubic, but in free-fall in the lateral degrees of freedom within the constellation plane. Also the option of a completely free spherical test mass with full laser interferometer readout has been conceptually investigated. The spherical test mass would rotate slowly, and would be allowed to tumble. Imperfections in roundness and density would be calibrated from differential wave front sensing in a tetrahedral arrangement, supported by added attitude information via a grid of tick marks etched onto the surface and monitored by the laser readout.
Relative seismic velocity variations correlate with deformation at Kīlauea volcano

PubMed Central

Donaldson, Clare; Caudron, Corentin; Green, Robert G.; Thelen, Weston A.; White, Robert S.

2017-01-01

Seismic noise interferometry allows the continuous and real-time measurement of relative seismic velocity through a volcanic edifice. Because seismic velocity is sensitive to the pressurization state of the system, this method is an exciting new monitoring tool at active volcanoes. Despite the potential of this tool, no studies have yet comprehensively compared velocity to other geophysical observables on a short-term time scale at a volcano over a significant length of time. We use volcanic tremor (~0.3 to 1.0 Hz) at Kīlauea as a passive source for interferometry to measure relative velocity changes with time. By cross-correlating the vertical component of day-long seismic records between ~230 station pairs, we extract coherent and temporally consistent coda wave signals with time lags of up to 120 s. Our resulting time series of relative velocity shows a remarkable correlation between relative velocity and the radial tilt record measured at Kīlauea summit, consistently correlating on a time scale of days to weeks for almost the entire study period (June 2011 to November 2015). As the summit continually deforms in deflation-inflation events, the velocity decreases and increases, respectively. Modeling of strain at Kīlauea suggests that, during inflation of the shallow magma reservoir (1 to 2 km below the surface), most of the edifice is dominated by compression—hence closing cracks and producing faster velocities—and vice versa. The excellent correlation between relative velocity and deformation in this study provides an opportunity to understand better the mechanisms causing seismic velocity changes at volcanoes, and therefore realize the potential of passive interferometry as a monitoring tool. PMID:28782009
LISA Long-Arm Interferometry

NASA Technical Reports Server (NTRS)

Thorpe, James I.

2009-01-01

An overview of LISA Long-Arm Interferometry is presented. The contents include: 1) LISA Interferometry; 2) Constellation Design; 3) Telescope Design; 4) Constellation Acquisition; 5) Mechanisms; 6) Optical Bench Design; 7) Phase Measurement Subsystem; 8) Phasemeter Demonstration; 9) Time Delay Interferometry; 10) TDI Limitations; 11) Active Frequency Stabilization; 12) Spacecraft Level Stabilization; 13) Arm-Locking; and 14) Embarassment of Riches.
Space Interferometry Science Working Group

NASA Astrophysics Data System (ADS)

Ridgway, Stephen T.

1992-12-01

Decisions taken by the astronomy and astrophysics survey committee and the interferometry panel which lead to the formation of the Space Interferometry Science Working Group (SISWG) are outlined. The SISWG was formed by the NASA astrophysics division to provide scientific and technical input from the community in planning for space interferometry and in support of an Astrometric Interferometry Mission (AIM). The AIM program hopes to measure the positions of astronomical objects with a precision of a few millionths of an arcsecond. The SISWG science and technical teams are described and the outcomes of its first meeting are given.
Robust interferometry against imperfections based on weak value amplification

NASA Astrophysics Data System (ADS)

Fang, Chen; Huang, Jing-Zheng; Zeng, Guihua

2018-06-01

Optical interferometry has been widely used in various high-precision applications. Usually, the minimum precision of an interferometry is limited by various technical noises in practice. To suppress such kinds of noises, we propose a scheme which combines the weak measurement with the standard interferometry. The proposed scheme dramatically outperforms the standard interferometry in the signal-to-noise ratio and the robustness against noises caused by the optical elements' reflections and the offset fluctuation between two paths. A proof-of-principle experiment is demonstrated to validate the amplification theory.
Elastic-plastic deformation of molybdenum single crystals shocked along [100

DOE PAGES

Mandal, A.; Gupta, Y. M.

2017-01-24

To understand the elastic-plastic deformation response of shock-compressed molybdenum (Mo) – a body-centered cubic (BCC) metal, single crystal samples were shocked along the [100] crystallographic orientation to an elastic impact stress of 12.5 GPa. Elastic-plastic wave profiles, measured at different propagation distances ranging between ~0.23 to 2.31 mm using laser interferometry, showed a time-dependent material response. Within experimental scatter, the measured elastic wave amplitudes were nearly constant over the propagation distances examined. These data point to a large and rapid elastic wave attenuation near the impact surface, before reaching a threshold value (elastic limit) of ~3.6 GPa. Numerical simulations ofmore » the measured wave profiles, performed using a dislocation-based continuum model, suggested that {110}<111> and/or {112}<111> slip systems are operative under shock loading. In contrast to shocked metal single crystals with close-packed structures, the measured wave profiles in Mo single crystals could not be explained in terms of dislocation multiplication alone. A dislocation generation mechanism, operative for shear stresses larger than that at the elastic limit, was required to model the rapid elastic wave attenuation and to provide a good overall match to the measured wave profiles. However, the physical basis for this mechanism was not established for the high-purity single crystal samples used in this study. As a result, the numerical simulations also suggested that Mo single crystals do not work harden significantly under shock loading in contrast to the behavior observed under quasi-static loading.« less
Mach-Zehnder interferometry method for acoustic shock wave measurements in air and broadband calibration of microphones.

PubMed

Yuldashev, Petr; Karzova, Maria; Khokhlova, Vera; Ollivier, Sébastien; Blanc-Benon, Philippe

2015-06-01

A Mach-Zehnder interferometer is used to measure spherically diverging N-waves in homogeneous air. An electrical spark source is used to generate high-amplitude (1800 Pa at 15 cm from the source) and short duration (50 μs) N-waves. Pressure waveforms are reconstructed from optical phase signals using an Abel-type inversion. It is shown that the interferometric method allows one to reach 0.4 μs of time resolution, which is 6 times better than the time resolution of a 1/8-in. condenser microphone (2.5 μs). Numerical modeling is used to validate the waveform reconstruction method. The waveform reconstruction method provides an error of less than 2% with respect to amplitude in the given experimental conditions. Optical measurement is used as a reference to calibrate a 1/8-in. condenser microphone. The frequency response function of the microphone is obtained by comparing the spectra of the waveforms resulting from optical and acoustical measurements. The optically measured pressure waveforms filtered with the microphone frequency response are in good agreement with the microphone output voltage. Therefore, an optical measurement method based on the Mach-Zehnder interferometer is a reliable tool to accurately characterize evolution of weak shock waves in air and to calibrate broadband acoustical microphones.
An atomic gravitational wave interferometric sensor in low earth orbit (AGIS-LEO)

NASA Astrophysics Data System (ADS)

Hogan, Jason M.; Johnson, David M. S.; Dickerson, Susannah; Kovachy, Tim; Sugarbaker, Alex; Chiow, Sheng-Wey; Graham, Peter W.; Kasevich, Mark A.; Saif, Babak; Rajendran, Surjeet; Bouyer, Philippe; Seery, Bernard D.; Feinberg, Lee; Keski-Kuha, Ritva

2011-07-01

We propose an atom interferometer gravitational wave detector in low Earth orbit (AGIS-LEO). Gravitational waves can be observed by comparing a pair of atom interferometers separated by a 30 km baseline. In the proposed configuration, one or three of these interferometer pairs are simultaneously operated through the use of two or three satellites in formation flight. The three satellite configuration allows for the increased suppression of multiple noise sources and for the detection of stochastic gravitational wave signals. The mission will offer a strain sensitivity of {<10^{-18}/sqrt{Hz}} in the 50mHz-10Hz frequency range, providing access to a rich scientific region with substantial discovery potential. This band is not currently addressed with the LIGO, VIRGO, or LISA instruments. We analyze systematic backgrounds that are relevant to the mission and discuss how they can be mitigated at the required levels. Some of these effects do not appear to have been considered previously in the context of atom interferometry, and we therefore expect that our analysis will be broadly relevant to atom interferometric precision measurements. Finally, we present a brief conceptual overview of shorter-baseline ({lesssim100 m}) atom interferometer configurations that could be deployed as proof-of-principle instruments on the International Space Station (AGIS-ISS) or an independent satellite.
Apoplastic sugars and cell-wall invertase are involved in formation of the tolerance of cold-resistant potato plants to hypothermia.

PubMed

Deryabin, A N; Burakhanova, E A; Trunova, T I

2015-01-01

We studied the involvement of apoplastic sugars (glucose, fructose, and sucrose) and the cell-wall invertase (CWI) in the formation of the tolerance of cold-resistant potato plants (Solanum tuberosum L., cv Désirée) to hypothermia. The activity of CW1 and the content in the cell and the apoplast substrate (sucrose) and the reaction products of this enzyme (glucose and fructose) have a significant influence on the formation of the tolerance of cold-resistant potato plants to hypothermia.
United States Air Force Research Initiation Program. 1985 Technical Report. Volume 2.

DTIC Science & Technology

1987-04-01

RESEARCH INITIATIO PORN 1985 TECHNICAL REPORT VOLUME 2(U) UNIVERSAL ENERGY SYSTEMS INC DAYTON OH R C DRRRAH APR 87 UNCLASSIFIED AFOSR-TR-87-1718 F492e-85-C...wi ves) may have to assume full responsibility for household chores and ’V child care during extended TVYs., and relinquish jobs to move with their...2 ’ Grjduate Degree 10% 5% At _east One Child iiiq ~Ho~.~ 9% 31% ,.IIlJ Livng at Hoyne 37% 56% Eployed Wives of Unemployed Wives of AF Oft icers (N=37
Information retrieval from holographic interferograms: Fundamentals and problems

NASA Technical Reports Server (NTRS)

Vest, Charles M.

1987-01-01

Holographic interferograms can contain large amounts of information about flow and temperature fields. Their information content can be very high because they can be viewed from many different directions. This multidirectionality, and fringe localization add to the information contained in the fringe pattern if diffuse illumination is used. Additional information, and increased accuracy can be obtained through the use of dual reference wave holography to add reference fringes or to effect discrete phase shift or hetrodyne interferometry. Automated analysis of fringes is possible if interferograms are of simple structure and good quality. However, in practice a large number of practical problems can arise, so that a difficult image processing task results.
Experimental study of the mutual influence of fibre Faraday elements in a spun-fibre interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gubin, V P; Morshnev, S K; Przhiyalkovsky, Ya V

2015-08-31

An all-spun-fibre linear reflective interferometer with two linked Faraday fibre coils is studied. It is found experimentally that there is mutual influence of Faraday fibre coils in this interferometer. It manifests itself as an additional phase shift of the interferometer response, which depends on the circular birefringence induced by the Faraday effect in both coils. In addition, the interferometer contrast and magneto-optical sensitivity of one of the coils change. A probable physical mechanism of the discovered effect is the distributed coupling of orthogonal polarised waves in the fibre medium, which is caused by fibre bend in the coil. (interferometry)
Fourier fringe analysis and its application to metrology of extreme physical phenomena: a review [Invited].

PubMed

Takeda, Mitsuo

2013-01-01

The paper reviews a technique for fringe analysis referred to as Fourier fringe analysis (FFA) or the Fourier transform method, with a particular focus on its application to metrology of extreme physical phenomena. Examples include the measurement of extremely small magnetic fields with subfluxon sensitivity by electron wave interferometry, subnanometer wavefront evaluation of projection optics for extreme UV lithography, the detection of sub-Ångstrom distortion of a crystal lattice, and the measurement of ultrashort optical pulses in the femotsecond to attosecond range, which show how the advantages of FFA are exploited in these cutting edge applications.
The Investigation of the Fundamental Limits of Heterodyne Holographic Interferometry with the Application of Imaging Laser Generated Lamb Waves

DTIC Science & Technology

1989-04-01

character*25 msg,echol,echo2,msgl character* 12 fname,vel,stepl,step2 character dvm(15),decl,dec2 integer numl,num2,row,col, icheck ,fig real data C fig...flg) linex = ’ send step2 error’ if (flg.ne.0) goto 8000 write (*,610) step2,echol c c 200 icheck = 0 c c ENTER FILE NAME c write (*,’(A/)’)’ Specify...dvm, data) write (*,660) i, icheck write (*,600) data write (3,640) data c c Increment Horizontal Position c msg - ’I1"’ call send855 (msg,echo 1,flg
Dual surface interferometer

DOEpatents

Pardue, Robert M.; Williams, Richard R.

1982-01-01

A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

Aeronomy report no. 74: The Urbana meteor-radar system; design, development, and first observations

NASA Technical Reports Server (NTRS)

Hess, G. C.; Geller, M. A.

1976-01-01

The design, development, and first observations of a high power meteor-radar system located near Urbana, Illinois are described. The roughly five-fold increase in usable echo rate compared to other facilities, along with automated digital data processing and interferometry measurement of echo arrival angles, permits unsurpassed observations of tidal structure and shorter period waves. Such observations are discussed. The technique of using echo decay rates to infer density and scale height and the method of inferring wind shear from radial acceleration are examined. An original experiment to test a theory of the Delta-region winter anomaly is presented.
Multipoint sensing with a low-coherence source using single-arm frequency-shifted interferometry

DOE PAGES

Zhang, Yiwei; Ye, Fei; Qi, Bing; ...

2016-07-12

We demonstrate that multiple-site sensing along an optical fiber can be done with incoherent continuous-wave light. Here, using a broadband low-coherence noise source, a slow detector, and an optical modulator, we construct a single-arm frequency-shifted interferometer (SA-FSI) capable of simultaneously sensing multiple weak-reflection sites distributed either in parallel or in series along fiber links. By scanning the driving frequency of an electro-optic amplitude modulator in the range of 2.7–3.2 GHz at steps of 41.7 KHz, we demonstrate a spatial resolution of 0.3 m and a measurement range of over 1 km.
Astronomical polarization studies at radio and infrared wavelengths. Part 1: Gravitational deflection of polarized radiation

NASA Technical Reports Server (NTRS)

Dennison, B. K.

1976-01-01

The gravitational field is probed in a search for polarization dependence in the light bending. This involves searching for a splitting of a source image into orthogonal polarizations as the radiation passes through the solar gravitational field. This search was carried out using the techniques of very long and intermediate baseline interferometry, and by seeking a relative phase delay in orthogonal polarizations of microwaves passing through the solar gravitational field. In this last technique a change in the total polarization of the Helios 1 carrier wave was sought as the spacecraft passed behind the sun. No polarization splitting was detected.
Interferometry of Klein tunnelling electrons in graphene quantum rings

NASA Astrophysics Data System (ADS)

de Sousa, D. J. P.; Chaves, Andrey; Pereira, J. M.; Farias, G. A.

2017-01-01

We theoretically study a current switch that exploits the phase acquired by a charge carrier as it tunnels through a potential barrier in graphene. The system acts as an interferometer based on an armchair graphene quantum ring, where the phase difference between interfering electronic wave functions for each path can be controlled by tuning either the height or the width of a potential barrier in the ring arms. By varying the parameters of the potential barriers, the interference can become completely destructive. We demonstrate how this interference effect can be used for developing a simple graphene-based logic gate with a high on/off ratio.
Real-Time Detection and Tracking of Vital Signs with an Ambulatory Subject Using Millimeter-Wave Interferometry

NASA Astrophysics Data System (ADS)

Mikhelson, Ilya V.

Finding a subject's heart rate from a distance without any contact is a difficult and very practical problem. This kind of technology would allow more comfortable patient monitoring in hospitals or in home settings. It would also allow another level of security screening, as a person's heart rate increases in stressful situations, such as when lying or hiding malicious intent. In addition, the fact that the heart rate is obtained remotely means that the subject would not have to know he/she is being monitored at all, adding to the efficacy of the measurement. Using millimeter-wave interferometry, a signal can be obtained that contains composite chest wall motion made up of component motions due to cardiac activity, respiration, and interference. To be of use, these components have to be separated from each other by signal processing. To do this, the quadrature and in-phase components of the received signal are analyzed to get a displacement waveform. After that, processing can be done on that waveform in either the time or frequency domains to find the individual heartbeats. The first method is to find the power spectrum of the displacement waveform and to look for peaks corresponding to heartbeats and respiration. Another approach is to examine the signal in the time domain using wavelets for multiresolution analysis. One more method involves studying the statistics of the wavelet-processed signal. The final method uses a heartbeat model along with probabilistic processing to find heartbeats. For any of the above methods to work, the millimeter-wave sensor has to be accurately pointed at the subject's chest. However, even small subject motions can render the rest of the gathered data useless as the antenna may have lost its aim. To combat this, a color and a depth camera are used with a servo-pan/tilt base. My program finds a face in the image and subsequently tracks that face through upcoming frames. The pan/tilt base adjusts the aim of the antenna depending on the subject's position. This makes the entire system self-aiming and also allows the subject to move to a new location and to have data acquisition continue.
TDRS orbit determination by radio interferometry

NASA Technical Reports Server (NTRS)

Pavloff, Michael S.

1994-01-01

In support of a NASA study on the application of radio interferometry to satellite orbit determination, MITRE developed a simulation tool for assessing interferometry tracking accuracy. The Orbit Determination Accuracy Estimator (ODAE) models the general batch maximum likelihood orbit determination algorithms of the Goddard Trajectory Determination System (GTDS) with the group and phase delay measurements from radio interferometry. ODAE models the statistical properties of tracking error sources, including inherent observable imprecision, atmospheric delays, clock offsets, station location uncertainty, and measurement biases, and through Monte Carlo simulation, ODAE calculates the statistical properties of errors in the predicted satellites state vector. This paper presents results from ODAE application to orbit determination of the Tracking and Data Relay Satellite (TDRS) by radio interferometry. Conclusions about optimal ground station locations for interferometric tracking of TDRS are presented, along with a discussion of operational advantages of radio interferometry.
Application of Hybrid Along-Track Interferometry/Displaced Phase Center Antenna Method for Moving Human Target Detection in Forest Environments

DTIC Science & Technology

2016-10-01

ARL-TR-7846 ● OCT 2016 US Army Research Laboratory Application of Hybrid Along-Track Interferometry/ Displaced Phase Center...Research Laboratory Application of Hybrid Along-Track Interferometry/ Displaced Phase Center Antenna Method for Moving Human Target Detection...TYPE Technical Report 3. DATES COVERED (From - To) 2015–2016 4. TITLE AND SUBTITLE Application of Hybrid Along-Track Interferometry/ Displaced
Topography Estimation of the Core Mantle Boundary with ScS Reverberations and Diffraction Waves

NASA Astrophysics Data System (ADS)

Hein, B. E.; Nakata, N.

2017-12-01

In this study, we use the propagation of global seismic waves to study the Core Mantle Boundary (CMB). We focus on the use of S-wave reflections at the CMB (ScS reverberations) and outer-core diffracted waves. It is difficult imaging the CMB with the ScS wave because the complexity of the structure in the near surface ( 50 km); the complex structure degrades the signal-to-noise ratio of of the ScS. To avoid estimating the structure in the crust, we rely on the concept of seismic interferometry to extract wave propagation through mantle, but not through the crust. Our approach is compute the deconvolution between the ScS (and its reverberation) and direct S waves generated by intermediate to deep earthquakes (>50 km depth). Through this deconvolution, we have the ability to filter out the direct S wave and retrieve the wave field propagating from only the hypocenter to the outer core, but not between the hypocenter to the receiver. After the deconvolution, we can isolate the CMB reflected waves from the complicated wave phenomena because of the near-surface structure. Utilizing intermediate and deep earthquakes is key since we can suppress the near-surface effect from the surface to the hypocenter of the earthquakes. The variation of such waves (e.g., travel-time perturbation and/or wavefield decorrelation) at different receivers and earthquakes provides the information of the topography of the CMB. In order to get a more detailed image of the topography of the CMB we use diffracted seismic waves such as Pdiff , Sdiff, and P'P'. By using two intermediate to deep earthquakes on a great circle path with a station we can extract the wave propagation between the two earthquakes to simplify the waveform, similar to how it is preformed using the ScS wave. We generate more illumination of the CMB by using diffracted waves rather than only using ScS reverberations. The accurate topography of CMB obtained by these deconvolution analyses may provide new insight of the dynamics of the Earth such as heat flow at the CMB and through the mantle.
ESA to test the smartest technique for detecting extrasolar planets from the ground

NASA Astrophysics Data System (ADS)

2002-03-01

GENIE will use ESO's Very Large Telescopes Credits: European Southern Observatory This photo shows an aerial view of the observing platform on the top of Paranal mountain (from late 1999), with the four enclosu Three 1.8-m VLTI Auxiliary Telescopes (ATs) and paths of the light beams have been superposed on the photo. Also seen are some of the 30 'stations' where the ATs will be positioned for observations and from where the light beams from the telescopes can enter the Interferometric Tunnel below. The straight structures are supports for the rails on which the telescopes can move from one station to another. The Interferometric Laboratory (partly subterranean) is at the centre of the platform. How nulling interferometry works Credits: ESA 2002/Medialab How nulling interferometry works In nulling interferometry, light from a distant star (red beams) hits each telescope, labelled T1 and T2, simultaneously. Before the resultant light beams are combined, the beam from one telescope is delayed by half a wavelength. This means that when the rays are brought together, peaks from one telescope line up with troughs from the other and so are cancelled out (represented by the straight red line), leaving no starlight. Light from a planet (blue beams), orbiting the star, enters the telescopes at an angle. This introduces a delay in the light reaching the second telescope. So, even after the half wavelength change in one of the rays, when the beams are combined they are reinforced (represented by the large blue waves) rather than cancelled out. Illustration by Medialab. Nulling interferometry combines the signal from a number of different telescopes in such a way that the light from the central star is cancelled out, leaving the much fainter planet easier to see. This is possible because light is a wave with peaks and troughs. Usually when combining light from two or more telescopes, a technique called interferometry, the peaks are lined up with one another to boost the signal. In nulling interferometry, however, the peaks are lined up with the troughs so they cancel out to nothing and the star disappears. Planets in orbit around the star show up, however, because they are offset from the central star and their light takes different paths through the telescope system. ESA and ESO will build a new instrument called GENIE (Ground-based European Nulling Interferometer Experiment) to perform nulling interferometry using ESO's Very Large Telescope (VLT), a collection of four 8-metre telescopes in Chile. It will be the biggest investigation of nulling interferometry to date. "It's being tested in the lab in a number of places but we can do more," says Malcolm Fridlund, project scientist for the Darwin mission at the European Space Research and Technology Centre, the Netherlands. "We intend to use the world's largest telescope and the world's largest interferometer to get very high resolution." Using GENIE to perfect this technique will provide invaluable information for engineers about how to build the 'hub' spacecraft of the Darwin flotilla. Scheduled for launch in the middle of the next decade Darwin is a collection of six space telescopes and two other spacecraft, which will together search for Earth-like planets around nearby stars. The hub will combine the light from the telescopes. "If you see the way of getting to Darwin as being outlined by a number of technological milestones this is one of the most important ones," says Malcolm Fridlund. Once up and running, GENIE will also provide a training ground for astronomers who will later use Darwin. For example, it will allow them to perfect their methods of interpreting Darwin data because, as well as the engineering tests, GENIE will be capable of real science. One of its greatest tasks will be to develop the target list of stars for Darwin to study. As recently discovered by ESA's Ulysses spaceprobe, the signature of a planetary system is probably a ring of dust surrounding the central star. GENIE will be able to look for these dust rings and make sure that the dust is not so dense that it will mask the planets from view. GENIE will see failed stars, known as brown dwarfs and, if the instrument performs to expectations, may also see some of the already-discovered giant planets. So far, these worlds have never been seen, only inferred to exist by the effect they have on their parent stars. From Earth, two things handicap nulling interferometry. Firstly, the atmosphere smears out the starlight so that its cancellation is a hundred times less effective than it will be in space. Secondly, planets are most easily seen using infrared wavelengths because they are warm. So, observing from the surface of Earth, itself a planet emitting infrared radiation, is like peering through fog. In space, these two problems disappear and Darwin will be able to see smaller, Earth-like worlds. "We have calculated that with Darwin we could see an 'Earth' if it were ten light-years away with a few hours of observation time. With the VLT, it would be impossible because of the atmosphere. Even if the atmosphere weren't there it would take 450 days because of the infrared background released by the Earth. So we have to go into space," says Fridlund. GENIE is expected to be on-line by 2006.
Optical Interferometry Motivation and History

NASA Technical Reports Server (NTRS)

Lawson, Peter

2006-01-01

A history and motivation of stellar interferometry is presented. The topics include: 1) On Tides, Organ Pipes, and Soap Bubbles; 2) Armand Hippolyte Fizeau (1819-1896); 3) Fizeau Suggests Stellar Interferometry 1867; 4) Edouard Stephan (1837-1923); 5) Foucault Refractor; 6) Albert A. Michelson (1852-1931); 7) On the Application of Interference Methods to Astronomy (1890); 8) Moons of Jupiter (1891); 9) Other Applications in 19th Century; 10) Timeline of Interferometry to 1938; 11) 30 years goes by; 12) Mount Wilson Observatory; 13) Michelson's 20 ft Interferometer; 14) Was Michelson Influenced by Fizeau? 15) Work Continues in the 1920s and 30s; 16) 50 ft Interferometer (1931-1938); 17) Light Paths in the 50 ft Interferometer; 18) Ground-level at the 50 ft; 19) F.G. Pease (1881-1938); 20) Timeline of Optical Interferometry to 1970; 21) A New Type of Stellar Interferometer (1956); 22) Intensity Interferometer (1963- 1976; 23) Robert Hanbury Brown; 24) Interest in Optical Interferometry in the 1960s; 25) Interferometry in the Early 1970s; and 26) A New Frontier is Opened up in 1974.
Manuscript title: antifungal proteins from moulds: analytical tools and potential application to dry-ripened foods.

PubMed

Delgado, Josué; Owens, Rebecca A; Doyle, Sean; Asensio, Miguel A; Núñez, Félix

2016-08-01

Moulds growing on the surface of dry-ripened foods contribute to their sensory qualities, but some of them are able to produce mycotoxins that pose a hazard to consumers. Small cysteine-rich antifungal proteins (AFPs) from moulds are highly stable to pH and proteolysis and exhibit a broad inhibition spectrum against filamentous fungi, providing new chances to control hazardous moulds in fermented foods. The analytical tools for characterizing the cellular targets and affected pathways are reviewed. Strategies currently employed to study these mechanisms of action include 'omics' approaches that have come to the forefront in recent years, developing in tandem with genome sequencing of relevant organisms. These techniques contribute to a better understanding of the response of moulds against AFPs, allowing the design of complementary strategies to maximize or overcome the limitations of using AFPs on foods. AFPs alter chitin biosynthesis, and some fungi react inducing cell wall integrity (CWI) pathway. However, moulds able to increase chitin content at the cell wall by increasing proteins in either CWI or calmodulin-calcineurin signalling pathways will resist AFPs. Similarly, AFPs increase the intracellular levels of reactive oxygen species (ROS), and moulds increasing G-protein complex β subunit CpcB and/or enzymes to efficiently produce glutathione may evade apoptosis. Unknown aspects that need to be addressed include the interaction with mycotoxin production by less sensitive toxigenic moulds. However, significant steps have been taken to encourage the use of AFPs in intermediate-moisture foods, particularly for mould-ripened cheese and meat products.
The Aspergillus fumigatus pkcA G579R Mutant Is Defective in the Activation of the Cell Wall Integrity Pathway but Is Dispensable for Virulence in a Neutropenic Mouse Infection Model

PubMed Central

Rocha, Marina Campos; de Godoy, Krissia Franco; de Castro, Patrícia Alves; Hori, Juliana Issa; Bom, Vinícius Leite Pedro; Brown, Neil Andrew; da Cunha, Anderson Ferreira; Goldman, Gustavo Henrique; Malavazi, Iran

2015-01-01

Aspergillus fumigatus is an opportunistic human pathogen, which causes the life-threatening disease, invasive pulmonary aspergillosis. In fungi, cell wall homeostasis is controlled by the conserved Cell Wall Integrity (CWI) pathway. In A. fumigatus this signaling cascade is partially characterized, but the mechanisms by which it is activated are not fully elucidated. In this study we investigated the role of protein kinase C (PkcA) in this signaling cascade. Our results suggest that pkcA is an essential gene and is activated in response to cell wall stress. Subsequently, we constructed and analyzed a non-essential A. fumigatus pkcA G579R mutant, carrying a Gly579Arg substitution in the PkcA C1B regulatory domain. The pkcA G579R mutation has a reduced activation of the downstream Mitogen-Activated Protein Kinase, MpkA, resulting in the altered expression of genes encoding cell wall-related proteins, markers of endoplasmic reticulum stress and the unfolded protein response. Furthermore, PkcAG579R is involved in the formation of proper conidial architecture and protection to oxidative damage. The pkcA G579R mutant elicits increased production of TNF-α and phagocytosis but it has no impact on virulence in a murine model of invasive pulmonary aspergillosis. These results highlight the importance of PkcA to the CWI pathway but also indicated that additional regulatory circuits may be involved in the biosynthesis and/or reinforcement of the A. fumigatus cell wall during infection. PMID:26295576
Phosphoproteomic Analysis of Protein Kinase C Signaling in Saccharomyces cerevisiae Reveals Slt2 Mitogen-activated Protein Kinase (MAPK)-dependent Phosphorylation of Eisosome Core Components*

PubMed Central

Mascaraque, Victoria; Hernáez, María Luisa; Jiménez-Sánchez, María; Hansen, Rasmus; Gil, Concha; Martín, Humberto; Cid, Víctor J.; Molina, María

2013-01-01

The cell wall integrity (CWI) pathway of the model organism Saccharomyces cerevisiae has been thoroughly studied as a paradigm of the mitogen-activated protein kinase (MAPK) pathway. It consists of a classic MAPK module comprising the Bck1 MAPK kinase kinase, two redundant MAPK kinases (Mkk1 and Mkk2), and the Slt2 MAPK. This module is activated under a variety of stimuli related to cell wall homeostasis by Pkc1, the only member of the protein kinase C family in budding yeast. Quantitative phosphoproteomics based on stable isotope labeling of amino acids in cell culture is a powerful tool for globally studying protein phosphorylation. Here we report an analysis of the yeast phosphoproteome upon overexpression of a PKC1 hyperactive allele that specifically activates CWI MAPK signaling in the absence of external stimuli. We found 82 phosphopeptides originating from 43 proteins that showed enhanced phosphorylation in these conditions. The MAPK S/T-P target motif was significantly overrepresented in these phosphopeptides. Hyperphosphorylated proteins provide putative novel targets of the Pkc1–cell wall integrity pathway involved in diverse functions such as the control of gene expression, protein synthesis, cytoskeleton maintenance, DNA repair, and metabolism. Remarkably, five components of the plasma-membrane-associated protein complex known as eisosomes were found among the up-regulated proteins. We show here that Pkc1-induced phosphorylation of the eisosome core components Pil1 and Lsp1 was not exerted directly by Pkc1, but involved signaling through the Slt2 MAPK module. PMID:23221999
Swim performance and thermoregulatory effects of wearing clothing in a simulated cold-water survival situation.

PubMed

Bowes, Heather; Eglin, Clare M; Tipton, Michael J; Barwood, Martin J

2016-04-01

Accidental cold-water immersion (CWI) impairs swim performance, increases drowning risk and often occurs whilst clothed. The impact of clothing on thermoregulation and swim performance during CWI was explored with the view of making recommendations on whether swimming is viable for self-rescue; contrary to the traditional recommendations. Ten unhabituated males (age 24 (4) years; height 1.80 (0.08) m; mass 78.50 (10.93) kg; body composition 14.8 (3.4) fat %) completed four separate CWIs in 12 °C water. They either rested clothed or naked (i.e. wearing a bathing costume) or swum self-paced clothed or naked for up to 1 h. Swim speed, distance covered, oxygen consumption and thermal responses (rectal temperature (T re), mean skin temperature (T msk) and mean body temperature T b) were measured. When clothed, participants swum at a slower pace and for a significantly shorter distance (815 (482) m, 39 (19) min) compared to when naked (1264 (564) m, 52 (18) min), but had a similar oxygen consumption indicating clothing made them less efficient. Swimming accelerated the rate of T msk and T b cooling and wearing clothing partially attenuated this drop. The impairment to swimming performance caused by clothing was greater than the thermal benefit it provided; participants withdrew due to exhaustion before hypothermia developed. Swimming is a viable self-rescue method in 12 °C water, however, clothing impairs swimming capability. Self-rescue swimming could be considered before clinical hypothermia sets in for the majority of individuals. These suggestions must be tested for the wider population.
Feasibility of satellite interferometry for surveillance, navigation, and traffic control

NASA Technical Reports Server (NTRS)

Gopalapillai, S.; Ruck, G. T.; Mourad, A. G.

1976-01-01

The feasibility of using a satellite borne interferometry system for surveillance, navigation, and traffic control applications was investigated. The evaluation was comprised of: (1) a two part systems analysis (software and hardware); (2) a survey of competitive navigation systems (both experimental and planned); (3) a comparison of their characteristics and capabilities with those of an interferometry system; and (4) a limited survey of potential users to determine the variety of possible applications for the interferometry system and the requirements which it would have to meet. Five candidate or "strawman" interferometry systems for various applications with various capabilities were configured (on a preliminary basis) and were evaluated. It is concluded that interferometry in conjunction with a geostationary satellite has an inherent ability to provide both a means for navigation/position location and communication. It offers a very high potential for meeting a large number of user applications and requirements for navigation and related functions.
Anomalous density and elastic properties of basalt at high pressure: Reevaluating of the effect of melt fraction on seismic velocity in the Earth's crust and upper mantle

NASA Astrophysics Data System (ADS)

Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Wang, Yanbin

2016-06-01

Independent measurements of the volumetric and elastic properties of Columbia River basalt glass were made up to 5.5 GPa by high-pressure X-ray microtomography and GHz-ultrasonic interferometry, respectively. The Columbia River basalt displays P and S wave velocity minima at 4.5 and 5 GPa, respectively, violating Birch's law. These data constrain the pressure dependence of the density and elastic moduli at high pressure, which cannot be modeled through usual equations of state nor determined by stepwise integrating the bulk sound velocity as is common practice. We propose a systematic variation in compression behavior of silicate glasses that is dependent on the degree of polymerization and arises from the flexibility of the aluminosilicate network. This behavior likely persists into the liquid state for basaltic melts resulting in weak pressure dependence for P wave velocities perhaps to depths of the transition zone. Modeling the effect of partial melt on P wave velocity reductions suggests that melt fraction determined by seismic velocity variations may be significantly overestimated in the crust and upper mantle.
Atom Interferometry: A Matter Wave Clock and a Measurement of α

NASA Astrophysics Data System (ADS)

Estey, Brian; Lan, Shau-Yu; Kuan, Pei-Chen; Hohensee, Michael; Haslinger, Philipp; Kehayias, Pauli; English, Damon; Müller, Holger

2012-06-01

Developments in large-momentum transfer beamsplitters (eg. Bragg diffraction) and conjugate Ramsey-Bord'e interferometers have enabled atom interferometers with unparalleled size and sensitivity. The atomic wave packet separation is large enough that the Coriolis force due to the earth's rotation reduces interferometer contrast. We compensate for this effect using a tip-tilt mirror, improving our contrast by up to a factor of 3.5, allowing pulse separations of up to 250 ms with 10k beamsplitters. This interferometer can be used to make a precise measurement of the recoil frequency (h/m) and thus the fine structure constant. The interferometer also gives us indirect access to the Compton frequency (νC≡mc^2/h) oscillations of the matter wave, since h/m is simply c^2/νC. Using an optical frequency comb we reference the interferometer's laser frequency to a multiple of a cesium atom's recoil frequency. This self-referenced interferometer thus locks a local oscillator to a specified fraction of the cesium Compton frequency, with a fractional stability of 2 pbb over several hours. This has potential application in redefining the kilogram in terms of the second. We also present a preliminary measurement of the fine structure constant.
Surface electrical properties experiment. [for Taurus-Littrow region of the moon on Apollo 17

NASA Technical Reports Server (NTRS)

Simmons, G.

1974-01-01

The Surface Electrical Properties Experiment (SEP) was flown to the moon in December 1972 on Apollo 17 and used to explore a portion of the Taurus-Littrow region. SEP used a relatively new technique, termed radio frequency interferometry (RFI). Electromagnetic waves were radiated from two orthogonal, horizontal electric dipole antennas on the surface of the moon at frequencies of 1, 2, 4, 8, 16, and 32 Mhz. The field strength of the EM waves was measured as a function of distance with a receiver mounted on the Lunar Roving Vehicle and using three orthogonal, electrically small, loops. The interference pattern produced by the waves that travelled above the moon's surface and those that travelled below the surface was recorded on magnetic tape. The tape was returned to earth for analysis and interpretation. Several reprints, preprints, and an initial draft of the first publication of the SEP results are included. These documents provide a rather complete account of the details of the theory of the RFI technique, of the terrestrial tests of the technique, and of the present state of our interpretation of the Apollo 17 data.
Anomalous density and elastic properties of basalt at high pressure: Reevaluating of the effect of melt fraction on seismic velocity in the Earth's crust and upper mantle

DOE PAGES

Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; ...

2016-06-27

Independent measurements of the volumetric and elastic properties of Columbia River basalt glass were made up to 5.5 GPa by high-pressure X-ray microtomography and GHz-ultrasonic interferometry, respectively. The Columbia River basalt displays P and S wave velocity minima at 4.5 and 5 GPa, respectively, violating Birch’s law. These data constrain the pressure dependence of the density and elastic moduli at high pressure, which cannot be modeled through usual equations of state nor determined by stepwise integrating the bulk sound velocity as is common practice. We propose a systematic variation in compression behavior of silicate glasses that is dependent on themore » degree of polymerization and arises from the flexibility of the aluminosilicate network. Likewise, this behavior likely persists into the liquid state for basaltic melts resulting in weak pressure dependence for P wave velocities perhaps to depths of the transition zone. By modeling the effect of partial melt on P wave velocity reductions it is suggested that melt fraction determined by seismic velocity variations may be significantly overestimated in the crust and upper mantle.« less
Study of transmission line attenuation in broad band millimeter wave frequency range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandya, Hitesh Kumar B.; Austin, M. E.; Ellis, R. F.

2013-10-15

Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmosphericmore » water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.« less

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