JT90 thermal barrier coated vanes

The technology of plasma sprayed thermal barrier coatings applied to turbine vane platforms in modern high temperature commercial engines was advanced to the point of demonstrated feasibility for application to commercial aircraft engines. The three thermal barrier coatings refined under this program are zirconia stabilized with twenty-one percent magnesia (21% MSZ), six percent yttria (6% YSZ), and twenty percent yttria (20% YSZ). Improvement in thermal cyclic endurance by a factor of 40 times was demonstrated in rig tests. A cooling system evolved during the program which featured air impingement cooling for the vane platforms rather than film cooling. The impingement cooling system, in combination with the thermal barrier coatings, reduced platform cooling air requirements by 44% relative to the current film cooling system. Improved durability and reduced cooling air requirements were demonstrated in rig and engine endurance tests. Two engine tests were conducted, one of 1000 cycles and the other of 1500 cycles. All three coatings applied to vanes fabricated with the final cooling system configuration completed the final 1500 cycle engine endurance test. Results of this test clearly demonstrated the durability of the 6% YSZ coating which was in very good condition after the test. The 21% MSZ and 20% YSZ coatings had numerous occurrences of significant spalling in the test

Evaluation of an Interferometric Sensor for In-Space Detection of Gas Leaks

Space mission planning often involves long-term storage of volatile liquids or high-pressure gases. These may include cryogenic fuels and oxidizers, high-pressure gases, and life-support-critical consumables. The risk associated with the storage of fluids and gases in space systems has long been an issue and the ability to retain these fluids is often tied to mission success. A leak in the storage or distribution system can cause many different problems, including a simple, but mission endangering, loss of inventory or, in severe cases, unbalanced thrust loads on a flight vehicle. Cryogenic propellants are especially difficult to store, especially over a long duration. The propellant can boil off and be lost through the insulating walls of the tank or simple thermal cycling of the fittings, valves, and propellant feed lines may unseat seals allowing the fluid to escape. Current NASA missions call for long-duration in-space storage of propellants, oxidizers, and life support supplies. Leaks of a scale detectable through a pressure drop in the storage tank are often catastrophic and have long been the focus of ground-based mitigation efforts where redundant systems are often employed. However, there is presently no technology available for detecting and monitoring low-level, but still mission-endangering, gas leaks in space. Standard in-space gas detection methods either have a very limited pressure range over which they operate effectively or are limited to certain gases. Mass spectrometer systems are able to perform the detection tasks, but their size, mass and use of high voltage, which could potentially lead to an arc that ignites a combustible propellent, severely limit their usefulness in a space system. In this paper, we present results from testing of the light-based interferometric gas monitoring and leak detection sensor shown in Fig. 1. The output of the sensor is an interference fringe pattern that is a function of the gas density, and commensurate index of refraction, in the sample region. Changes in the density of gas cause the interference fringes to move across a photodiode detector, providing a temporal history of the leak. The sensor is fiber coupled and constructed from solid optics, allowing for placement almost anywhere on the spacecraft. It is also advantageous in that it consumes very little power and does not introduce an ignition source. Data are presented demonstrating the capability of the sensor to measure density variations in different gas species. In addition, the transient response of the sensor in vacuum is demonstrated. These data extend and improve upon the results previously presented by the authors in Ref. [1]

Positiivisen pedagogiikan mahdollisuudet lisätä positiivista vuorovaikutusta päiväkodin henkilökunnan ja vanhempien välisessä yhteistyössä

Tiivistelmä. Päiväkoti on usealle perheelle paikka, jossa käydään joka arkipäivä, jossa voi tavata samassa elämäntilanteessa olevia ihmisiä ja jossa asiantunteva henkilökunta jakaa kasvatusvastuun vanhempien kanssa. Tällä hetkellä kasvatuksen ja opetuksen kentällä puhutaan paljon positiivisesta pedagogiikasta ja se näkyy myös valtakunnallisissa varhaiskasvatustyötä ohjaavissa asiakirjoissa. Tämän kandidaatin työn tavoitteena on selvittää, mitä positiivinen pedagogiikka tarkoittaa käytännössä päiväkodissa ja voidaanko sen avulla vaikuttaa vanhempien kanssa tehtävään yhteistyöhön. Työni kattaa varhaiskasvatusikäisten päiväkodissa käyvien lasten perheet sekä esiopetusikäisten perheet, mikäli lapsen esiopetus järjestetään päiväkodissa. Työni lähtökohtana on positiivisen psykologian teoriaan pohjautuva positiivinen pedagogiikka sekä varhaiskasvatustyötä ohjaavat valtakunnalliset ohjeistukset. Tutkielma on toteutettu laadullisena tutkimuksena ja tutkimusmenetelmänä on käytetty kirjallisuuskatsausta. Lähteinä käytin suomen ja englannin kielistä tutkimuskirjallisuutta ja -artikkeleita sekä Varhaiskasvatussuunnitelman perusteita ja varhaiskasvatuslakia. Tutkimukseni perusteella voidaan todeta, että yhteistyö alkaa jo jopa ennen lapsen päiväkotiin tulemista. Vanhempien on tärkeä saada heti yhteistyön alussa tunne, että heitä kuunnellaan ja juuri heidän ja heidän lapsensa tunteet ja mielipiteet ovat tärkeitä. Positiivisen vuorovaikutuksen ja sujuvan yhteistyön ytimessä on molemminpuolinen luottamus vanhempien ja henkilökunnan välillä. Tätä tukee henkilökunnan aidosti välittävä ja positiivinen suhde ryhmän lapsiin, jota positiivisen pedagogiikan käyttö rakentaa ja vahvistaa. Positiivinen pedagogiikka vallitsevana työskentelytapana läpäisee henkilökunnan ja lasten välisten suhteiden lisäksi myös henkilökunnan ja vanhempien suhteet lisäten positiivista vuorovaikutusta

A Fiber-Optic Sensor for Leak Detection in a Space Environment

A miniature fiber-optic, laser-based, interferometric leak detector is presented for application as a means to detect on-orbit gas leaks. The sensor employs a fiber-coupled modified Michelson interferometer to detect gas leaks by measuring an increase in gas density in the sensing region. Monitoring changes in the fringe pattern output by the interferometer allows for direct measurement of the gas density in the sensing region and, under the assumption of an equation of state, this can be used to obtain a pressure measurement. Measurements obtained over a pressure range from 20 mtorr to 760 torr using a prototypical interferometer on working gases of air, nitrogen, argon, and helium generally exhibit agreement with a theoretical prediction of the pressure increase required before an interference fringe completely moves over the detector. Additional measurements performed on various gases demonstrate the range of detectable species, measuring sub-torr pressure changes in the process. A high-fidelity measurement places the ultimate pressure resolution for this particular sensor configuration in the 10 mtorr range. Time-resolved data prove the capability of this sensor to detect fast gas flow phenomena associated with transients and pressure waves

A comparative study of the in vitro permeation of ibuprofen in mammalian skin, the PAMPA model and silicone membrane

Human skin remains the membrane of choice when conducting in vitro studies to determine dermal penetration of active pharmaceutical ingredients or xenobiotics. However there are ethical and safety issues associated with obtaining human tissue. For these reasons synthetic membranes, cell culture models or in silico predictive algorithms have been researched intensively as alternative approaches to predict dermal exposure in man. Porcine skin has also been recommended as an acceptable surrogate for topical or transdermal delivery research. Here we examine the in vitro permeation of a model active, ibuprofen, using human or porcine skin, as well as the Parallel Artificial Membrane Permeation Assay (PAMPA) model and silicone membrane. Finite dose studies were conducted in all models using commercial ibuprofen formulations and simple volatile ibuprofen solutions. The dose applied in the PAMPA model was also varied in order to determine the amount of applied formulation which best simulates typical amounts of topical products applied by patients or consumers. Permeation studies were conducted up to 6 h for PAMPA and silicone and up to 48 h for human and porcine skin. Cumulative amounts permeated at 6 h were comparable for PAMPA and silicone, ranging from 91–136 g/cm2 across the range of formulations studied. At 48 h, maximum ibuprofen permeation in human skin ranged from 11–38 g/cm2 and corresponding values in porcine skin were 59–81 g/cm2. A dose of 1 l/cm2 was confirmed as appropriate for finite dose studies in the PAMPA model. The formulation which delivered the greatest amount of ibuprofen in human skin was also significantly more efficient than other formulations when evaluated in the PAMPA model. The PAMPA model also discriminated between different formulation types (i.e. gel versus solution) compared with other models. Overall, the results confirm the more permeable nature of the PAMPA, silicone membrane and porcine tissue models to ibuprofen compared with human skin. Further finite dose studies to elucidate the effects of individual excipients on the barrier properties of the PAMPA model are needed to expand the applications of this model. The range of actives that are suitable for study using the model also needs to be delineated

Optical system and method for gas detection and monitoring

A free-space optical path of an optical interferometer is disposed in an environment of interest. A light beam is guided to the optical interferometer using a single-mode optical fiber. The light beam traverses the interferometer's optical path. The light beam guided to the optical path is combined with the light beam at the end of the optical path to define an output light. A temporal history of the output light is recorded

Entorno educativo digital como herramienta de cambios complejos de la actividad pedagógica del profesor

The authors of the article identified four basic functions of the use of information technology in the course of training future representatives of a profession: information and training, forming, evaluation and correction, research.  It is noted that these functions do not operate separately, but as elements of a single system, depending on the conditions determined by the features of the information EE. The analysis allows the authors of the article to assert that at this stage of the educational process evolution the main task is to create a methodology related to the use of information management technologies in the development of electronic materials of educational nature and their implementation in the context of pedagogical activity.Los autores del artículo identificaron cuatro funciones básicas del uso de la tecnología de la información en el curso de la capacitación de futuros representantes de una profesión: información y capacitación, formación, evaluación y corrección, investigación. Cabe señalar que estas funciones no funcionan por separado, sino como elementos de un solo sistema, dependiendo de las condiciones determinadas por las características de la información EE. El análisis permite a los autores del artículo afirmar que en esta etapa de la evolución del proceso educativo, la tarea principal es crear una metodología relacionada con el uso de tecnologías de gestión de la información en el desarrollo de materiales electrónicos de naturaleza educativa y su implementación en el contexto de actividad pedagógica

Removing Orbital Debris with Lasers

Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the use of LEO space is threatened by runaway collisional cascading. A problem predicted more than thirty years ago, the threat from debris larger than about 1 cm demands serious attention. A promising proposed solution uses a high power pulsed laser system on the Earth to make plasma jets on the objects, slowing them slightly, and causing them to re-enter and burn up in the atmosphere. In this paper, we reassess this approach in light of recent advances in low-cost, light-weight modular design for large mirrors, calculations of laser-induced orbit changes and in design of repetitive, multi-kilojoule lasers, that build on inertial fusion research. These advances now suggest that laser orbital debris removal (LODR) is the most cost-effective way to mitigate the debris problem. No other solutions have been proposed that address the whole problem of large and small debris. A LODR system will have multiple uses beyond debris removal. International cooperation will be essential for building and operating such a system.Comment: 37 pages, 15 figures, in preparation for submission to Advances in Space Researc

The possibilities of optical methods in the early diagnosis of gliomas

A novel approach based on the Raman and absorption spectroscopy for detection of gliomas molecular markers in brain tissue and blood will be discussed. Using the mice model of the U87 human glioblastoma, we have shown the possibility of glioma development control by a combination of Raman, infrared (IR), and Terahertz (THz) pulsed spectroscopy