Evolution of the streamwise vortices in a coaxial jet controlled with micro flap-actuators

A coaxial jet was actively controlled by a MEMS-fabricated micro flap actuator nozzle. The effect of different control modes on secondary azimuthal instabilities and the evolution of streamwise vortices were investigated by applying stereoscopic PIV to the cross-stream plane of the jet. Forcing with non-symmetric modes, in particular the least-stable helical mode, accelerates the evolution of the streamwise vortices through the enhancement of azimuthal instabilities. Although forcing is applied to the outer shear layer of the outer jet, the control effect is most pronounced in the inner shear layer of the inner jet. Unlike in the natural jet, streamwise vortices appear in the inner shear layer of the controlled jet. For forcing with the fundamental axisymmetric mode, a Strouhal number of the order of unity maximise the azimuthal instabilities and hence the counts of the streamwise vortices. The present result is in accordance with our previous experimental findings in the longitudinal plane, where the evolution of the primary vortices and mixing between the inner and the outer jets were examined through 2D-PIV and PLI

Taloyhtiön pihasaneeraus : Esimerkkikohteena As Oy Kananlaulu

Työn taustana käytettiin lähiöiden suurimman aikakauden, 1960- ja 1970-lukujen kerrostalojen ajankohtaista peruskorjaustarvetta. Peruskorjaustarve koskee niin kiinteistön piha-aluetta kuin kiinteistön muitakin osia. Pihojen suurin korjaustarve perustuu kuluneiden kalusteiden, varusteiden, kasvillisuuden ja muiden osien huonokuntoisuuteen. Lisäksi muuttuneet turvallisuusvaatimukset sekä esteettömyyden haasteet tuovat lisätarvetta pihojen saneerauksille. Työni tavoitteena oli lisätä viihtyisyyttä ja parantaa Asunto Oy Kananlaulun piha-aluetta sen saneerauksella. Saneerauksessa huomioidaan metsälähiön tyypilliset pihasuunnittelun erityispiirteet. Piha-alueen analyysin avulla arvioitiin sen nykytilaa paikan päällä kohteessa. Samalla tutustuttiin myös suunnitelma- ja urakka-asiakirjoihin. Työn pohjana tutkittiin kerrostalorakentamisen ja niiden piha-aluerakentamisen kehitystä Suomessa. Tietopohjaksi haettiin tietoa myös kerrostalopihojen kunnostuksesta ja kunnostusprosessista. Tuloksena oli kirjallinen selostus piharakentamisen vaiheista. Työni toimeksiantajana oli VRJ Pohjois-Suomi Oy. Työn tulokset ovat hyödynnettävissä kerrostalopihojen peruskorjaushankkeissa. Asunto Oy Kananlaulun piha-analyysi ja pihasaneeraus voidaan liittää osaksi Kaukovainion kehittämistä. Työn tulokset antavat myös minulle itselleni mahdollisuuden kehittää omaa osaamistani viherrakentamisen työnjohdossa.As a background for the work was used the topical need of renovation in the block of flats in the suburbs built in the 1960- and 1970´s. The renovation need applies both to the yard and the other parts of the property. The biggest need of renovation is based on the poor condition of the worn out equipment, vegetation and other parts of the yard. Furthermore the changed requirements of safety and accessibility increase the renovation need. The goal on my work was to add the comfort and attractiveness of the yard of Asunto Oy Kananlaulu. During the renovation the typical characteristics of a wooden suburb were taken into account. The present situation of the yard was estimated on site. At the same time I familiarized myself the documents of planning and subcontracting. For the background of the work the development of the building of the block of flats and their yards was investigated. Also the renovation of yards and the process of renovation was studied. The result of the work is a written report of the stages of the yard construction. The principal of the work was VRJ Pohjois-Suomi Oy. The results of the work can be utilized in high-rise yards’ renovation projects. The analyses and renovation of the yard can be linked to the development of Kaukovainio area. The results of the work gave me the possibility to develop my own skills on supervision of work at green construction

Bremsstrahlung in Alpha-Decay

We present the first fully quantum mechanical calculation of photon radiation accompanying charged particle decay from a barrier resonance. The soft-photon limit agrees with the classical results, but differences appear at next-to-leading-order. Under the conditions of alpha-decay of heavy nuclei, the main contribution to the photon emission stems from Coulomb acceleration and may be computed analytically. We find only a small contribution from the tunneling wave function under the barrier.Comment: 12 pages, 2 Postscript figure

Ionizing radiation exposure and the development of soft-tissue sarcomas in atomic-bomb survivors

BACKGROUND: Very high levels of ionizing radiation exposure have been associated with the development of soft-tissue sarcoma. The effects of lower levels of ionizing radiation on sarcoma development are unknown. This study addressed the role of low to moderately high levels of ionizing radiation exposure in the development of soft-tissue sarcoma. METHODS: Based on the Life Span Study cohort of Japanese atomic-bomb survivors, 80,180 individuals were prospectively assessed for the development of primary soft-tissue sarcoma. Colon dose in gray (Gy), the excess relative risk, and the excess absolute rate per Gy absorbed ionizing radiation dose were assessed. Subject demographic, age-specific, and survival parameters were evaluated. RESULTS: One hundred and four soft-tissue sarcomas were identified (mean colon dose = 0.18 Gy), associated with a 39% five-year survival rate. Mean ages at the time of the bombings and sarcoma diagnosis were 26.8 and 63.6 years, respectively. A linear dose-response model with an excess relative risk of 1.01 per Gy (95% confidence interval [CI]: 0.13 to 2.46; p = 0.019) and an excess absolute risk per Gy of 4.3 per 100,000 persons per year (95% CI: 1.1 to 8.9; p = 0.001) were noted in the development of soft-tissue sarcoma. CONCLUSIONS: This is one of the largest and longest studies (fifty-six years from the time of exposure to the time of follow-up) to assess ionizing radiation effects on the development of soft-tissue sarcoma. This is the first study to suggest that lower levels of ionizing radiation may be associated with the development of soft-tissue sarcoma, with exposure of 1 Gy doubling the risk of soft-tissue sarcoma development (linear dose-response). The five-year survival rate of patients with soft-tissue sarcoma in this population was much lower than that reported elsewhere.published_or_final_versio

Radiation correction to astrophysical fusion reactions and the electron screening problem

We discuss the effect of electromagnetic environment on laboratory measurements of the nuclear fusion reactions of astrophysical interest. The radiation field is eliminated using the path integral formalism in order to obtain the influence functional, which we evaluate in the semi-classical approximation. We show that enhancement of the tunneling probability due to the radiation correction is extremely small and does not resolve the longstanding problem that the observed electron screening effect is significantly larger than theoretical predictions.Comment: 9 pages, 1 eps figure

Determination of the Gamow-Teller Quenching Factor from Charge Exchange Reactions on 90Zr

Double differential cross sections between 0-12 degrees were measured for the 90Zr(n,p) reaction at 293 MeV over a wide excitation energy range of 0-70 MeV. A multipole decomposition technique was applied to the present data as well as the previously obtained 90Zr(p,n) data to extract the Gamow-Teller (GT) component from the continuum. The GT quenching factor Q was derived by using the obtained total GT strengths. The result is Q=0.88+/-0.06 not including an overall normalization uncertainty in the GT unit cross section of 16%.Comment: 11 papes, 4 figures, submitted to Physics Letters B (accepted), gzipped tar file, changed content

Performance Test of a BaF2 Detector System for High Energy γ-rays

開始ページ、終了ページ: 冊子体のページ付