Cardan Gear Mechanism versus Slider-Crank Mechanism in Pumps and Engines

In machine design we always want to save space, save energy and produce as much power as possible. We can often reduce accelerations, inertial loads and energy consumption by changing construction. In this study the old cardan gear mechanism (hypocycloid mechanism) has been compared with the conventional slider-crank mechanism in air pumps and four-stroke engines. Comprehensive Newtonian dynamics has been derived for the both mechanisms. First the slidercrank and the cardan gear machines have been studied as lossless systems. Then the friction losses have been added to the calculations. The calculation results show that the cardan gear machines can be more efficient than the slider-crank machines. The smooth running, low mass inertia, high pressures and small frictional power losses make the cardan gear machines clearly better than the slider-crank machines. The dynamic tooth loads of the original cardan gear construction do not rise very high when the tooth clearances are kept tight. On the other hand the half-size crank length causes high bearing forces in the cardan gear machines. The friction losses of the cardan gear machines are generally quite small. The mechanical efficiencies are much higher in the cardan gear machines than in the slider-crank machines in normal use. Crankshaft torques and power needs are smaller in the cardan gear air pumps than in the equal slider-crank air pumps. The mean crankshaft torque and the mean output power are higher in the cardan gear four-stroke engines than in the slider-crank four-stroke engines in normal use. The cardan gear mechanism is at its best, when we want to build a pump or an engine with a long connecting rod (≈ 5⋅crank length) and a thin piston (≈ 1.5⋅crank length) rotating at high angular velocity and intermittently high angular acceleration. The cardan gear machines can be designed also as slide constructions without gears. Suitable applications of the cardan gear machines are three-cylinder half-radial engines for motorcycles, sixcylinder radial engines for airplanes and six-cylinder double half-radial engines for sport cars. The applied equations of Newtonian dynamics, comparative calculations, calculation results (tables, curves and surface plots) and recommendations presented in this study hold novelty value and are unpublished before. They have been made and written by the author first time in this study.

Tuottavuuden mittaaminen ja johtaminen Etelä-Karjalan keskussairaalassa

Tutkimuksen tavoitteena oli arvioida, miten tuottavuustietoa voidaan hyödyntää johtamisen tukena ja kuinka tuottavuustietoa tällä hetkellä hyödynnetään Etelä-Karjalan keskussairaalassa (EKKS). Tuottavuuden mittaamisessa hyödynnetään Terveyden- ja hyvinvoinnin laitoksen (THL) vuosittain julkaisemassa Hoito-toiminnan tuottavuus -tilastossa käytettävää tuottavuuden mittaamismenetelmää, jossa panoksina ovat sairaalan tai erikoisalan hoitotoiminnasta aiheutuneet kustannukset ja tuotoksina NordDRG-ryhmittelijän avulla painotetut hoitojaksot ja käynnit. Tutkimuksessa arvioitiin tuottavuuden mittaamiseen liittyvien mahdollisten virhetekijöiden vaikutusta sairaalan tuottavuuteen EKKS:n tapauksessa ja tämän perusteella tunnistettiin, miten THL:n julkaisemaa tuottavuustilastoa ja sisäistä tuottavuustietoa voidaan hyödyntää sairaalan johtamisen tukena. Pääasiallisena aineistona työssä käytettiin EKKS:n henkilöstön haastatteluja ja sairaalan taloudellisia raportteja sekä THL:n julkista ja julkaisematonta aineistoa. THL:n kehittämän hoitotoiminnan tuottavuuden mittaamismenetelmän havaittiin soveltuvan yksittäisen sairaalan käyttöön tietyin muutoksin. Vaadittavien muutosten lisäksi tutkimuksessa tunnistettiin taustatekijät, jotka THL:n tuottavuustilaston ja sisäisen tuottavuustiedon tulkitsijan tulee ottaa huomioon. EKKS:n tuottavuustietojen keruussa havaittiin kehittämiskohteita, joita paran-tamalla tuottavuustiedon luotettavuutta ja hyödynnettävyyttä voidaan edelleen kehittää. Tuottavuustiedon hyödyntämistä voidaan niin ikään edelleen kehittää EKKS:ssa.

Very High Energy Gamma-Rays emitting BL LAC's Population Study

Context: BL Lacs are the most numerous extragalactic objects which are detected in Very High Energy (VHE) gamma-rays band. They are a subclass of blazars. Large flux variability amplitude, sometimes happens in very short time scale, is a common characteristic of them. Significant optical polarization is another main characteristics of BL Lacs. BL Lacs' spectra have a continuous and featureless Spectral Energy Distribution (SED) which have two peaks. Among 1442 BL Lacs in the Roma-BZB catalogue, only 51 are detected in VHE gamma-rays band. BL Lacs are most numerous (more than 50% of 514 objects) objects among the sources that are detected above 10 GeV by FERMI-LAT. Therefore, many BL Lacs are expected to be discovered in VHE gamma-rays band. However, due to the limitation on current and near future technology of Imaging Air Cherenkov Telescope, astronomers are forced to predict whether an object emits VHE gamma-rays or not. Some VHE gamma-ray prediction methods are already introduced but still are not confirmed. Cross band correlations are the building blocks of introducing VHE gamma-rays prediction method. Aims: We will attempt to investigate cross band correlations between flux energy density, luminosity and spectral index of the sample. Also, we will check whether recently discovered MAGIC J2001+435 is a typical BL Lac. Methods: We select a sample of 42 TeV BL Lacs and collect 20 of their properties within five energy bands from literature and Tuorla blazar monitoring program database. All of the data are synchronized to be comparable to each other. Finally, we choose 55 pair of datasets for cross band correlations finding and investigating whether there is any correlation between each pair. For MAGIC J2001+435 we analyze the publicly available SWIFT-XRT data, and use the still unpublished VHE gamma-rays data from MAGIC collaboration. The results are compared to the other sources of the sample. Results: Low state luminosity of multiple detected VHE gamma-rays is strongly correlated luminosities in all other bands. However, the high state does not show such strong correlations. VHE gamma-rays single detected sources have similar behaviour to the low state of multiple detected ones. Finally, MAGIC J2001+435 is a typical TeV BL Lac. However, for some of the properties this source is located at the edge of the whole sample (e.g. in terms of X-rays flux). Keywords: BL Lac(s), Population study, Correlations finding, Multi wavelengths analysis, VHE gamma-rays, gamma-rays, X-rays, Optical, Radio