Solar Twins and Solar Analogues in Galactic Surveys.

The Sun is a crucial benchmark for how we see the universe. Especially when it comes to the visible range of the spectrum, stars are commonly compared to the Sun, as it is the most thoroughly studied star. In this work I have focussed on two aspects of the Sun and how it is used in modern astronomy. Firstly, I try to answer the question on how similar to the Sun another star can be. Given the limits of observations, we call a solar twin a star that has the same observed parameters as the Sun within its errors. These stars can be used as stand-in suns when doing observations, as normal night-time telescopes are not built to be pointed at the Sun. There have been many searches for these twins and every one of them provided not only information on how close to the Sun another star can be, but also helped us to understand the Sun itself. In my work I have selected _ 300 stars that are both photometrically and spectroscopically close to the Sun and found 22 solar twins, of which 17 were previously unknown and can therefore help the emerging picture on solar twins. In my second research project I have used my full sample of 300 solar analogue stars to check the temperature and metallicity scale of stellar catalogue calibrations. My photometric sample was originally drawn from the Geneva-Copenhagen-Survey (Nordström et al. 2004; Holmberg et al. 2007, 2009) for which two alternative calibrations exist, i.e. GCS-III (Holmberg et al. 2009) and C11 (Casagrande et al. 2011). I used very high resolution spectra of solar analogues, and a new approach to test the two calibrations. I found a zero–point shift of order of +75 K and +0.10 dex in effective temperature and metallicity, respectively, in the GCS-III and therefore favour the C11 calibration, which found similar offsets. I then performed a spectroscopic analysis of the stars to derive effective temperatures and metallicities, and tested that they are well centred around the solar values.

Kylmälaitekoneikon runkorakenteen kehittäminen

Kylmälaitekoneikot ovat kylmäkomponentteja sisältäviä rakenteita, joiden avulla toteutetaan suurten tilojen, kuten elintarvikemyymälöiden sisäilman jäähdytys. Lisäksi koneikkojen avulla jäähdytetään matalampiin lämpötiloihin pienempiä kylmähuoneita. Osa koneikoista ottaa talteen kylmäprosessissa syntyvän lämmön, jota hyödynnetään tilojen lämmityksessä. Tämän diplomityön tavoitteena oli suunnitella ja mitoittaa kahdeksalle eri kylmälaitekoneikolle entistä kustannustehokkaammat runkorakenteet, jotka ovat niin kestäviä, että koneikkoja on mahdollista pinota tilan säästämiseksi kolme päällekkäin. Lisäksi runkorakenteilta vaadittiin helppoa kuljetettavuutta, hyviä kiinnitysominaisuuksia ja korroosionkestävyyttä. Aluksi työssä selvitettiin runkorakenteisiin kohdistuvat vaatimukset, jonka jälkeen materiaalin valinta tehtiin materiaaliin kohdistuvien vaatimusten perusteella. Rakenteiden palkit mitoitettiin tarvittavan taivutusvastuksen ja kiepahduksen mukaan. Pilarit puolestaan mitoitettiin nurjahduksen ja kaksiaksiaalisen taivutustilan perusteella. Tämän jälkeen mitoitettiin eri sauvojen väliset hitsi- ja ruuviliitokset siten, että rakenne hajoaa ylikuormitustilanteessa mahdollisimman turvallisesti. Työssä tehdyt laskelmat varmennettiin elementtimenetelmän avulla ja lopullisille rakenteille tehtiin elementtimenetelmällä vielä ominaistaajuusanalyysejä. Lopuksi työssä suunniteltiin runkorakenteille sopiva korroosionsuojaus.

Influence of intrauterine and extrauterine growth on neurodevelopmental outcome of monozygotic twins

There have been indications that intrauterine and early extrauterine growth can influence childhood mental and motor function. The objective of the present study was to evaluate the influence of intrauterine growth restriction and early extrauterine head growth on the neurodevelopmental outcome of monozygotic twins. Thirty-six monozygous twin pairs were evaluated at the corrected age of 12 to 42 months. Intrauterine growth restriction was quantified using the fetal growth ratio. The effects of birth weight ratio, head circumference at birth and current head circumference on mental and motor outcomes were estimated using mixed-effect linear regression models. Separate estimates of the between (interpair) and within (intrapair) effects of each measure on development were thus obtained. Neurodevelopment was assessed with the Bayley Scales of Infant Development, 2nd edition, by a psychologist blind to the exposure. A standardized neurological examination was performed by a neuropediatrician who was unaware of the exposures under investigation. After adjustment, birth weight ratio and head circumference at birth were not associated with motor or mental outcomes. Current head circumference was associated with mental but not with motor outcomes. Only the intrapair twin effect was significant. An increase of 1 cm in current head circumference of one twin compared with the other was associated with 3.2 points higher in Mental Developmental Index (95%CI = 1.06-5.32; P < 0.03). Thus, no effect of intrauterine growth was found on cognition and only postnatal head growth was associated with cognition. This effect was not shared by the co-twin.

The effects of water and sucrose contents on the physicochemical properties of non-directly expanded rice flour extrudates

Rice flour was processed by extrusion cooking in the presence of variable contents of water and sucrose. The process was carried out in a twin-screw extruder under the conditions given by a centre rotational experimental design of second order. The effects of the independent variables, water content (27.9 to 42.1%), and sucrose content (0.1 to 19.9%) on the physicochemical properties of the extrudates were investigated. The water absorption index (WAI), water solubility index (WSI), volumetric expansion index (VEI), and bulk density (BD) were determined as dependent variables. BD was determined for samples before and after frying. An increase in water contents resulted in higher WAI and VEI, and lower WSI and BD for extrudates before and after frying. Higher sucrose levels led to increased values of WAI and VEI and to reduced values of WSI and BD. Both independent variables had significant influence on the physicochemical properties of rice flour extrudates. However, the sucrose content was the most significant. The interaction between these two independent variables and their quadratic effect were also important for the responses studied.

Effect of sugar and water contents on non-expanded cassava flour extrudates

The effects of sucrose and water contents on cassava flour processed by extrusion at varied concentrations of sucrose (0-20% w/w) and water (28-42% w/w) were studied by applying response surface methodology. The extrusion of the mixtures was performed in a twin screw extruder fitted to a torque rheometer. The specific mechanical energy (SME) dissipated inside a conical twin-screw extruder was measured. Water absorption index (WAI), water solubility index (WSI) and paste viscosity readings (cold viscosity (CV), peak viscosity (PV), breakdown (BD) and set back (SB)) during a gelatinization-retrogradation cycle measured in a Rapid Visco Analyzer were determined on non-directly extruded products. The results indicated that SME and WSI decreased as a function of water and sucrose contents. WAI and pasting properties were influenced by water content. A non antiplasticizing effect of the sucrose content was observed on pasting properties, suggesting that sucrose did not reduce the availability of water available for gelatinizing cassava flour during the extrusion process. The nature of the optimum point was characterized as a saddle point for WAI, WSI, PV and BD, whereas SME showed a maximum and CV and SB a minimum. The results indicated to be valuable for the production of non-expanded cassava flour extrudates with desirable functional properties for specific end users.

Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954. Stamped on the back: Taylor Publishing Co. Job Number 30232 - Pict. No. 4 - Page No. 56 - Chapman College - Orange, Calif.

Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California

Reeves Hall and part of Roosevelt Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California,1979

Reeves Hall, Chapman College, Orange, California, June, 1979. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Helicopter landing near Reeves Hall, Chapman College, Orange, California

Helicopter landing near Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Students on lawn by Reeves Hall, Chapman College, Orange, California

Reeves Hall, Chapman College, Orange, California. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.

Reeves Hall, Chapman College, Orange, California, November, 1964.

Reeves Hall, Chapman College, Orange, California, November, 1964. This historical building (2 floors, 17,862 sq.ft.), completed in 1913 is named in honor of George N. Reeves, president of the university from 1942 to 1956. It is listed in the National Registry for Historical Buildings and houses the Kathleen Muth Reading Center, College of Lifelong Learning, and the School of Education. Originally constructed to serve Orange Union High School, it was designed along with its twin building by Santa Ana architect Frank Eley. Acquired by Chapman College in 1954.