Surface-referenced current meter measurements

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1991A general discussion of possible techniques for observation of near-surface currents indicates that the surface-following frame of reference will provide several advantages over the Eulerian or Lagrangian frames. One problem with surface-following measurements is the biasing effects of the waves. A technique for making unbiased measurements is developed. This technique requires that both the sensor velocity and the fluid velocity be measured. A sensor platform, the Surface Acoustic Shear Sensor (SASS), which makes the required measurements is described. The processing scheme for interpreting the measurements from the SASS is described at length. The data that SASS has obtained from two deployments in the Shelf Mixed Layer Experiment (SMILE) is presented. This data shows clearly that the biasing effects of waves can not, in general, be ignored. In the summary of the data we find surprisingly little shear in the downwind direction in the top 4m of the water column. In the crosswind direction observed, observed shear seems to be indicative of an across shelf pressure gradient and intense near-surface mixing.Financial support for my work was from NSF grant OCE-87-16937

The surface acoustic shear sensor (SASS) as used during the Shelf Mixed Layer Experiment (SMILE) November 1988-March 1989

The SMILE (Shelf Mixed Layer Experiment) field program took place during the winter of 1988-1989. The SMILE program itself was large and involved many investigators and instruments. This report documents the use of the Surface Acoustic Shear Sensor (SASS) as part of the suite of measurements taken during SMILE. The SMILE mooring array was deployed from early November 1988 until June, 1989. SASS, being a newly developed instrument, was deployed for two shorter periods; a test deployment between November 26 and December 8, 1988, and a longer second deployment, February 23 through March 14, 1989. SASS is based on BASS (Benthic Acoustic Stress Sensor) components (Williams et al., 1987), mounted on a structure that allowed continuous sampling of velocity, temperature and conductivity in the top five meters of the ocean. BASS was modified for this surface application to acquire data from a gyro, and conductivity sensors. The attitude data from the gyro allows the velocities of the current meter to be referenced to an inertial frame of reference. The other data obtained from SASS will be used to calculate shear current gradients, and other descriptors of turbulence and mixing.Prepared for the National Science Foundation under Contract Number OCE-8716937

Kaksikielinen pedagogiikka ja kielelliset oikeudet viittovan oppilaan opetuksessa

Tiivistelmä. Suomen lakeja, säädöksiä ja kielipoliittisia lausuntoja tarkasteltaessa näyttäisi, että viittomakielisten oppilaiden kielelliset oikeudet on hyvin turvattu. Perusopetuksen opetussuunnitelmaan sekä lakiteksteihin on kirjattu, että opetuksen on oltava viittomakielistä tarvittaessa. Viittomakielestä ja sen eri variaatioista eivät hyödy vain kuurot, vaan myös huonokuuloiset ja kuuroutuneet. Viittomakieli ja sen variaatiot ovat kuitenkin monelle viittovia oppilaita opettavalle vieraita kielenmuotoja, jotka tulee opiskella erikseen. Viittovat oppilaat ovat myös usein kaksikielisiä, jolloin opetuskielten on oltava tätä tukevaa. Opettajilta vaaditaankin erilaisia valmiuksia opettaa viittoen. Tämän pro gradu -tutkielman tavoitteena onkin selvittää, millaisia valmiuksia erityisopettajilla on opettaa viittoen sekä millaisia pedagogisia ja kielellisiä ratkaisuja viittovissa luokissa tehdään. Tutkielman keskiössä ovat kielelliset oikeudet ja niiden toteutuminen. Tutkielman teoreettinen viitekehys tarkastelee viittovan henkilön kaksikielisyyttä sekä äidinkielten eroavaisuuksia. Lisäksi tarkastellaan tasa-arvoisten kielellisten oikeuksien laki- ja säädösperusteita sekä viittovan oppilaan opetuksessa huomioitavia asioita. Tutkielma on laadullinen tutkimus, jonka metodologinen lähestymistapa on fenomenografia ja metodina on käytetty haastatteluja. Tutkimusaineisto on kerätty strukturoiduilla teemahaastatteluilla, joihin on osallistunut yhdeksän opettajaa eri puolilta Suomea. Aineiston analyysissä on hyödynnetty fenomenografista analyysimallia. Tutkimustulokset osoittavat, että kielelliset oikeudet ovat kouluissa tiedostettuja, mutta käytännön tasolla toteutus voi olla haastavaa. Tähän vaikuttavat oleellisimmin opettajan kielitaito sekä oppilasaineksen muuttuminen (kuuroja viittomakielisiä oppilaita ei ole enää useita). Muuttunut oppilasaines vaikuttaa lisäksi viittovan luokan kielivalintoihin. Tuloksissa kiteytettiin, että viittovan oppilaan opetus tulee olla kaksikielistä, kieli- ja kulttuuri-identiteetti huomioivaa, visuaalista sekä oppilaan kieltä arvostavaa. Opettajan valmiuteen opettaa viittoen vaikuttavat koulutustausta, jolla opettaja on voinut viittomistaitoa hankkia. Haastatellut opettajat kaipaavat erityispedagogiikan koulutukseen viittomiskursseja, mutta tärkeämmässä roolissa nähdään työnantajat, joiden kouluissa opettajille tulisi järjestää eritasoisia viittomakursseja. Johtopäätöksenä esitetään, että viittovan oppilaan opetuksessa on otettava monipuolisesti huomioon kolmen tekijän kombinaatio: kaksikielinen pedagogiikka, kielelliset oikeudet sekä viittova oppimisympäristö. Vaikka viittomakieli ei olisi viittovan oppilaan kommunikaatio, voi viittomat olla erittäin tärkeitä kommunikaation edistäjiä. Tutkielmaa voi soveltaa viittovien oppilaiden opetuksen toteuttamisessa sekä yhteiskunnallisessa keskustelussa kielellisesti tasa-arvoisen opetuksen järjestämisessä.Bilingual pedagogic and linguistic rights in sign education. Abstract. Linguistic rights of sign language pupils are well assured by the Finnish laws, regulations and linguistic verdicts. Sign language with its different variations are not benefitting only deafs but as well hard of hearings. Curriculum of basic education and the Finnish laws include the statement that teaching must be operated using sign language when needed. However, sign language with its variations are foreign language forms for the teachers and they are to be studied separately. Pupils using signs are often bilingual thus the teaching pedagogic must support this. Therefore teachers must have different kind of readiness to sign education. The goal of this Master’s Thesis is to clarify which kind of readiness the special education teachers have for sign education as well as what kind of pedagogical and linguistic decisions are made in classrooms using signs. The essence of this thesis is linguistic rights and their implementation. Theoretic framefork of this thesis examines bilinguality of person using signs and the differencies of mother tongues. Additionally, laws and regulations for equal linguistic rights and essential matters to be taken into account in teaching are considered. This thesis is a qualitative research using phenomenography as a methological approach. Interviews are used as a method. The reseach data has been collected by structured theme interviews with nine teachers accross Finland. The analysis is based on phenomenographic model. According to the results linguistic rights are well known in schools but practical implementation may be challenging. This is mostly affected by language proficiency of the teacher and the change in pupil base (the number of deaf sign language users is decreasing).The changed pupil base affects also on language choices in the classroom. The teaching of the pupil using signs must be bilingual and visual. The language and cultural identities must be considered and pupil’s language must be appreciated. The education and training courses for signing skills have a major influense for teacher’s readiness for sign education. There is a need for signing courses in special education training but it is more important to arrange signing courses for teachers in schools. The conclusion of this Master’s Thesis is that the teaching of the pupil using signs must consider the combination of three factors: Bilingual pedagogic, linguistic rights, and signing study environment. Although sign language is not the communication of the pupil signs can have an important role as a contributor of communication. This study can be applied in realisation of sign education and in social discussion regarding to arrangement of equal linguistic education

Asymmetric emission of high energy electrons in the two-dimensional hydrodynamic expansion of large xenon clusters irradiated by intense laser fields

Energy spectra and angular distributions have been measured of electrons that are emitted upon disassembly of $Xe_{150000}$ following irradiation by intense (10$^{15}-10^{16}$ W cm$^{-2}$) laser pulses whose durations are varied over the 100-2200 fs range. The cluster explosion dynamics occur in the hydrodynamic regime. Electron emission is found to be unexpectedly asymmetric and exhibits a resonance when the laser pulse duration is $\sim$1 ps. These results are rationalized by extending the hydrodynamic model to also take into account the force that the light field exerts on the polarization charge that is induced on surface of the cluster. We show that the magnitude of this electrostrictive force is comparable to those of Coulombic and the hydrodynamic forces, and it exhibits resonance behavior. Contrary to earlier understanding, we find that low-energy electrons are connected to the resonance in energy absorption by the cluster. The high-energy electrons seem to be produced by a mechanism that is not so strongly influenced by the resonance.Comment: 1 Revtex file, 8 figs. in eps forma

Cervical adenocarcinoma presenting as a cardiac tamponade in a 57-year-old woman: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pericardial effusion as a complication of malignant gynecological disorders is rare. Few cases of endometrial cancer, squamous cell carcinoma of the cervix, ovarian cancer and uterine carcinosarcoma have been previously reported. We report the first case of cardiac tamponade secondary to a cervical adenocarcinoma.</p> <p>Case presentation</p> <p>A 54-year-old Caucasian woman, without any relevant medical history and no gynecological aftercare, was admitted to our hospital emergency room with severe dyspnea. Echocardiography revealed severe pericardial effusion with a swinging heart. An emergency pericardial drainage was performed through a pericardial window, which permitted the draining of 700 mL of bloody fluid and a pericardial biopsy. Cytological examination of the fluid revealed atypical cells, and the biopsy specimen showed tumor emboli suggestive of adenocarcinoma. Magnetic resonance imaging showed a 35 mm cervical lesion indicative of an endocervical tumor. Exploratory laparoscopy revealed diffuse peritoneal lesions and histological examination of cervical curettage showed a poorly differentiated micropapillary adenocarcinoma of the cervix.</p> <p>Conclusion</p> <p>Carcinomatous pericarditis as the first symptom of a malignant gynecological adenocarcinoma has not, to the best of our knowledge, been documented before. This case highlights the extreme severity of pericardial effusion secondary to cervical adenocarcinoma, a sign of advanced disease. Gynecological malignancies have to be considered in cases of neoplastic pericardial effusion.</p

Additively manufactured hierarchical stainless steels with high strength and ductility

Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength–ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications

Beryllium global erosion and deposition at JET-ILW simulated with ERO2.0

The recently developed Monte-Carlo code ERO2.0 is applied to the modelling of limited and diverted discharges at JET with the ITER-like wall (ILW). The global beryllium (Be) erosion and deposition is simulated and compared to experimental results from passive spectroscopy. For the limiter configuration, it is demonstrated that Be self-sputtering is an important contributor (at least 35%) to the Be erosion. Taking this contribution into account, the ERO2.0 modelling confirms previous evidence that high deuterium (D) surface concentrations of up to similar to 50% atomic fraction provide a reasonable estimate of Be erosion in plasma-wetted areas. For the divertor configuration, it is shown that drifts can have a high impact on the scrape-off layer plasma flows, which in turn affect global Be transport by entrainment and lead to increased migration into the inner divertor. The modelling of the effective erosion yield for different operational phases (ohmic, L- and H-mode) agrees with experimental values within a factor of two, and confirms that the effective erosion yield decreases with increasing heating power and confinement.Peer reviewe

Dynamic modelling of local fuel inventory and desorption in the whole tokamak vacuum vessel for auto-consistent plasma-wall interaction simulations

An extension of the SolEdge2D-EIRENE code package, named D-WEE, has been developed to add the dynamics of thermal desorption of hydrogen isotopes from the surface of plasma facing materials. To achieve this purpose, D-WEE models hydrogen isotopes implantation, transport and retention in those materials. Before launching autoconsistent simulation (with feedback of D-WEE on SolEdge2D-EIRENE), D-WEE has to be initialised to ensure a realistic wall behaviour in terms of dynamics (pumping or fuelling areas) and fuel content. A methodology based on modelling is introduced to perform such initialisation. A synthetic plasma pulse is built from consecutive SolEdge2D-EIRENE simulations. This synthetic pulse is used as a plasma background for the D-WEE module. A sequence of plasma pulses is simulated with D-WEE to model a tokamak operation. This simulation enables to extract at a desired time during a pulse the local fuel inventory and the local desorption flux density which could be used as initial condition for coupled plasma-wall simulations. To assess the relevance of the dynamic retention behaviour obtained in the simulation, a confrontation to post-pulse experimental pressure measurement is performed. Such confrontation reveals a qualitative agreement between the temporal pressure drop obtained in the simulation and the one observed experimentally. The simulated dynamic retention during the consecutive pulses is also studied.Peer reviewe