Elastic thickness structure of the Andaman subduction zone: Implications for convergence of the Ninetyeast Ridge

We use the Bouguer coherence (Morlet isostatic response function) technique to compute the spatial variation of effective elastic thickness (T-e) of the Andaman subduction zone. The recovered T-e map resolves regional-scale features that correlate well with known surface structures of the subducting Indian plate and the overriding Burma plate. The major structure on the India plate, the Ninetyeast Ridge (NER), exhibits a weak mechanical strength, which is consistent with the expected signature of an oceanic ridge of hotspot origin. However, a markedly low strength (0< T-e <3 km) in that region, where the NER is close to the Andaman trench (north of 10 N), receives our main attention in this study. The subduction geometry derived from the Bouguer gravity forward modeling suggests that the NER has indented beneath the Andaman arc. We infer that the bending stresses of the viscous plate, which were reinforced within the subducting oceanic plate as a result of the partial subduction of the NER buoyant load, have reduced the lithospheric strength. The correlation, T-e < T-s (seismogenic thickness) reveals that the upper crust is actively deforming beneath the frontal arc Andaman region. The occurrence of normal-fault earthquakes in the frontal arc, low Te zone, is indicative of structural heterogeneities within the subducting plate. The fact that the NER along with its buoyant root is subducting under the Andaman region is inhibiting the subduction processes, as suggested by the changes in trench line, interrupted back-arc volcanism, variation in seismicity mechanism, slow subduction, etc. The low T-e and thinned crustal structure of the Andaman back-arc basin are attributed to a thermomechanically weakened lithosphere. The present study reveals that the ongoing back-arc spreading and strike-slip motion along the West Andaman Fault coupled with the ridge subduction exerts an important control on the frequency and magnitude of seismicity in the Andaman region. (C) 2013 Elsevier Ltd. All rights reserved.

Características antropométricas, condición física y velocidad de lanzamiento en balonmano de élite y amateur

166 p.

Kadete eta jubenil futbolarien arteko ezberdintasunak jauzi, azelerazio eta norabide aldaketa gaitasunetan

Helburua: Ikerketa honen helburu nagusia kadete eta jubenil futbolarien arteko ezberdintasunak analizatzea izan zen azelerazio, norabide aldaketa, jauzi bertikal eta jauzi horizontal gaitasunetan. Metodoak: Lagina Romo Futbol Club-aren 34 futbol jokalarik osatu zuten, denak gizonezkoak (16,03 ± 1,22 urte, 1,73 ± 0,07 m, 66,86 ± 7,65 kg, 22,21 ± 1,91 kg.m-2). Lagina bi taldetan banatu egin zen, lehiatzen zuten kategoria kontutan hartuta. 1.taldeak (KAD) Kadeteen Euskal Ligan jokatzen zuen (15,12 ± 0,70 urte, 1,71 ± 0,07 m, 63,06 ± 6,66 kg, 21,48 ± 1,56 kg.m-2), 2.taldeak (JUB) Jubenilen Nazional Ligan egiten zuen bitartean (16,94 ± 0,90 urte, 1,76 ± 0,07 m, 70,65 ± 6,77 kg, 22,93 ± 2,00 kg.m-2). Testak bi egun ezberdinetan burutu egin ziren eta jokalariek ez zuten intentsitate altuko jarduerarik egin frogen aurreko bi egunetan. 1.egunean, asteartea, jokalari guztien datu antropometrikoak hartu ziren eta azelerazio gaitasuna, norabide aldaketa gaitasuna (CODA) eta jauzi horizontala (HJ) neurtzeko testak burutu ziren. 2.egunean, osteguna, salto bertikalari (VJ) dagozkion frogak eraman ziren aurrera. Emaitzak: Azelerazio gaitasunean ezberdintasun esanguratsuak eskuratu ziren kadeteen eta jubenilen artean. Hala ere, MAT testan lortutako emaitzak antzekoak izan ziren bi taldeetan. Ezberdintasun esanguratsuak eskuratu ziren elastizitate indizean (IE) eta efektuaren tamaina altua edo moderatua izan zen VCMJ eta CMJAS frogetan. Ezberdintasun esanguratsuak aurkitu ziren bai HCMJ jauzian zein H3BT jauzian jokalari kadete eta jubenilen artean. Konklusioa: Ikerketa honetan kategorien arteko ezberdintasunak aurkitu ziren (kadete eta jubenil) azelerazio gaitasunean, baina ez norabide aldaketa gaitasunean. Jauzi gaitasunari dagokionez, jokalari jubenilek jauzi horizontal gaitasun handiagoa eskuratu zuten. Hala ere, ezberdintasun hauek ez ziren ikusi jauzi bertikal mota guztietan. Kontra mugimendurik gabeko jauzi bertikal testan (VSJ), emaitzak antzekoak izan ziren adin ezberdinetako jokalarien artean. Emaitza hauei erreparatuz, interesgarria izan daiteke azelerazio (5 eta 15 m), luzatze-laburtze ziklodun jauzi bertikal (VCMJ eta VCMJAS) eta jauzi horizontal (HCMJ eta H3BT) testak erabiltzea errendimendua analizatzeko futbolari gazteetan.

A Study of Fan-Distortion Interaction Within the NASA Rotor 67 Transonic Stage

The performance of a transonic fan operating within nonuniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-deg sector of the inlet flow field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the nonuniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analyzed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow features downstream of the fan stage, which arise due to the three dimensionality of the flow and unsteadiness. © 2012 American Society of Mechanical Engineers.

Ultrafast and widely tuneable vertical-external-cavity surface-emitting laser, mode-locked by a graphene-integrated distributed Bragg reflector

We report a versatile and cost-effective way of controlling the unsaturated loss, modulation depth and saturation fluence of graphene-based saturable absorbers (GSAs), by changing the thickness of a spacer between SLG and a high-reflection mirror. This allows us to modulate the electric field intensity enhancement at the GSA from 0 up to 400%, due to the interference of incident and reflected light at the mirror. The unsaturated loss of the SLG-mirror-assembly can be reduced to$\sim$0. We use this to mode-lock a VECSEL from 935 to 981nm. This approach can be applied to integrate SLG into various optical components, such as output coupler mirrors, dispersive mirrors, dielectric coatings on gain materials. Conversely, it can also be used to increase absorption (up to 10%) in various graphene based photonics and optoelectronics devices, such as photodetectors.

Wavelength tunable graphene modelocked VECSEL

We passively modelock an optically pumped VECSEL by using a single-layer graphene saturable absorber mirror, resulting in pulses as short as 473 fs. A broad wavelength tuning range of 46 nm is achieved with three different VECSEL chips, with a single chip 21 nm are covered. © OSA 2013.

Graphene saturable absorbers for VECSELs

We report mode-locking of an optically pumped VECSEL using a graphene-based saturable absorber mirror (GSAM). Self-starting and stable modelocked operation is demonstrated with 473 fs pulses at 1.5 GHz repetition rate and 949 nm center wavelength. Wavelength tuning is achieved over a 46 nm bandwidth. We discuss the mirror design, the fabrication of the GSAMs, and give an outlook on further optimization of the design, including dielectric top coatings to protect the graphene and to increase the flexibility in the design. © 2014 SPIE.

Graphene modelocked VECSELs

In the past decade, passively modelocked optically pumped vertical external cavity surface emitting lasers (OPVECSELs), sometimes referred to as semiconductor disk lasers (OP-SDLs), impressively demonstrated the potential for generating femtosecond pulses at multi-Watt average output powers with gigahertz repetition rates. Passive modelocking with a semiconductor saturable absorber mirror (SESAM) is well established and offers many advantages such as a flexible design of the parameters and low non-saturable losses. Recently, graphene has emerged as an attractive wavelength-independent alternative saturable absorber for passive modelocking in various lasers such as fiber or solid-state bulk lasers because of its unique optical properties. Here, we present and discuss the modelocked VECSELs using graphene saturable absorbers. The broadband absorption due to the linear dispersion of the Dirac electrons in graphene makes this absorber interesting for wavelength tunable ultrafast VECSELs. Such widely tunable modelocked sources are in particularly interesting for bio-medical imaging applications. We present a straightforward approach to design the optical properties of single layer graphene saturable absorber mirrors (GSAMs) suitable for passive modelocking of VECSELs. We demonstrate sub-500 fs pulses from a GSAM modelocked VECSEL. The potential for broadband wavelength tuning is confirmed by covering 46 nm in modelocked operation using three different VECSEL chips and up to 21 nm tuning in pulsed operation is achieved with one single gain chip. A linear and nonlinear optical characterization of different GSAMs with different absorption properties is discussed and can be compared to SESAMs. © 2014 SPIE.

Passively modelocked VECSEL using a single-layer graphene saturable absorber mirror

Optically pumped ultrafast vertical external cavity surface emitting lasers (VECSELs), also referred to as semiconductor disk lasers (SDLs), are very attractive sources for ps- and fs-pulses in the near infrared [1]. So far VECSELs have been passively modelocked with semiconductor saturable absorber mirrors (SESAMs, [2]). Graphene has emerged as a promising saturable absorber (SA) for a variety of applications [3-5], since it offers an almost unlimited bandwidth and a fast recovery time [3-5]. A number of different laser types and gain materials have been modelocked with graphene SAs [3-4], including fiber [5] and solid-state bulk lasers [6-7]. Ultrafast VECSELs are based on a high-Q cavity, which requires very low-loss SAs compared to other lasers (e.g., fiber lasers). Here we develop a single-layer graphene saturable absorber mirror (GSAM) and use it to passively modelock a VECSEL. © 2013 IEEE.