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- Havtun, Hans, et al.
(författare)
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The Green Room : A Giant Leap in Development of Energy-efficient Cooling Solutions for Datacenters
- 2013
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Ingår i: Sustainability in Energy and Buildings. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642366444 ; , s. 743-755
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Konferensbidrag (refereegranskat)abstract
- Nowadays, promoting energy-efficient solutions will have a strong return on investment not only economically but also socially and environmentally. As an added value to economic savings, the carbon footprint of the companies will be reduced and contribute to slowing down the environmental degradation and global warming. The IT-sector is no exception in this aspect. Swedish-Finnish Company TeliaSonera has taken a giant leap in the development of energy reduction by introducing the Green Room Concept which combines not only an energy-efficient cooling production but also an efficient way of distributing the cooling air flow inside the room. Both of these technologies will reduce the energy needed for cooling the equipment on their own, but combining them ensures a very energy-efficient datacenter. Although geothermal cooling or free-cooling would be the preferred choice for cooling production, it is dependent on the geographical location and climate conditions of the site, and investment potential of the company and hence not a possible solution in all cases. For these cases, the Green Room can be installed with a conventional chiller-based cooling production and still reduce the energy consumption. The main feature of the Green Room concept is that the air coolers are installed along the length of the room parallel to the cabinet rows which will minimize the air flow complications in the cold aisle. This delivers cold air to the cabinet in a straight flow path to the racks and hence avoids the conventional raised floor to deliver cold air. One of the downsides of raised floor air-distribution is that it usually suffers from maldistribution of cooling air meaning that some racks suffer from inadequate cooling. The improved air flow distribution of the Green Room concept consequently leads to a more efficient cooling system. By carefully ensuring that no cold air bypasses the racks, any unwanted mixture of hot and cold air is also eliminated. In conventional datacenters, this problem usually occurs because proper hot/cold aisle separation is often neglected during construction. Furthermore, while many conventional datacenters face numerous problems as a result of messy cablings both inside and outside of the cabinets, the Green Room concept has managed to resolve these issues thanks to an effective cable management. The research method in this project was to conduct a series of experimental tests to collect as much necessary data as possible. During tests, temperatures inside the cold and hot aile were monitored and recorded. Special emphasis was put on measuring the temperature distribution in the cold aisle as the temperatures reflect the air distribution. Afterwards, the parameters used to evaluate the efficiency of the system were calculated and in some parts, simulated. Finally, the results were compared with other equivalent data and measurement from other datacenters and conclusions were made based on them. In addition to quantitative results based on a variety of calculations, the qualitative characteristics of this approach are also included to provide the readers with a better outlook on the system while being compared to other solutions currently available for datacenters. To assess the energy efficiency of a datacenter, critical measures such as Power Usage Effectiveness (PUE), defined as the total site power consumption divided by the power consumption of the IT-services, as well as the Coefficient of Performance (COP), defined as the power consumtion of the IT-services divded by the power consumtion needed to operate the cooling system. Results show that the PUE with room operational temperature of 22.5 °C can be as low as 1.05 for for a Green Room with geothermal cooling production, 1.11 for free-cooling, and 1.50 for chiller-based cooling production using old chillers and 1.32 for chiller-based cooling production using modern and more advanced chillers as compared to a PUE of 2.0 for a typical raised floor datacenter.
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- Biver, N., et al.
(författare)
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Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 589, s. Art. no. A78-
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Tidskriftsartikel (refereegranskat)abstract
- The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in March-April 2013 and January 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. We observed comet Lovejoy with the IRAM 30 m telescope between 13 and 26 January 2015, and with the Odin submillimeter space observatory on 29 January-3 February 2015. We detected 22 molecules and several isotopologues. The (H2O)-O-16 and (H2O)-O-18 production rates measured with Odin follow a periodic pattern with a period of 0.94 days and an amplitude of similar to 25%. The inferred isotope ratios in comet Lovejoy are O-16/O-18 = 499 +/- 24 and D/H = 1.4 +/- 0.4 x 10(-4) in water, S-32/S-34 = 24.7 +/- 3.5 in CS, all compatible with terrestrial values. The ratio C-12/C-13 = 109 +/- 14 in HCN is marginally higher than terrestrial and N-14/N-15 = 145 +/- 12 in HCN is half the Earth ratio. Several upper limits for D/H or C-12/C-13 in other molecules are reported. From our observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an Oort Cloud comet that is not larger than the terrestrial value. On the other hand, the observation of the same HDO line in the other Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous measurements of D/H in cometary water, this illustrates that a diversity in the D/H ratio and in the chemical composition, is present even within the same dynamical group of comets, suggesting that current dynamical groups contain comets formed at very different places or times in the early solar system.
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| 4. |
- Fukuda, Yoshiharu, et al.
(författare)
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High quality nutrient intake is associated with higher household expenditures by Japanese adults
- 2012
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Ingår i: Bioscience trends. - Tokyo, Japan : International Advancement Center for Medicine & Health Research Co., Ltd.. - 1881-7823 .- 1881-7815. ; 6:4, s. 176-82
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Tidskriftsartikel (refereegranskat)abstract
- There is little evidence of socioeconomic differences in dietary intake in the Japanese population. This study examined the association between household expenditures and dietary intake using nationally representative surveys of Japan. We analyzed data from the Comprehensive Survey of Living Conditions and National Health and Nutrition Survey, 2003-2007. For subjects ages 18 to 74 years (11,240 men and 11,472 women), the sex-specific association between household expenditure quartiles and selected nutrient intake was examined using comparison of means and prevalence of a healthy intake. Higher household expenditures were associated with an increase in the mean levels of total energy, fat, protein, carbohydrates, calcium, vitamins A and C, niacin, and fiber for both men and women and salt for men. Prevalence comparison indicated that most of the recommendations for dietary intake were met for people with higher household expenditures than for those with lower household expenditures. There was no clear association between fat intake and expenditures. Higher household expenditures were associated with a healthy and balanced nutrient intake in Japanese adults. The findings suggest that socioeconomic differences in dietary patterns contribute to socioeconomic inequalities in mortality and morbidity in Japan.
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| 5. |
- Bhandage, Amol K., 1988-, et al.
(författare)
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Expression of GABA receptors subunits in peripheral blood mononuclear cells is gender dependent, altered in pregnancy and modified by mental health
- 2015
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 213:3, s. 575-585
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Tidskriftsartikel (refereegranskat)abstract
- AimThe concept of nerve-driven immunity recognizes a link between the nervous and the immune system. -aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain, and receptors activated by GABA can be expressed by immune cells. Here, we examined whether the expression of GABA receptors and chloride transporters in human peripheral blood mononuclear cells (PBMCs) was influenced by gender, pregnancy or mental health. MethodsWe used RT-qPCR to determine the mRNA expression level in PBMCs from men (n=16), non-pregnant women (n=19), healthy pregnant women (n=27) and depressed pregnant women (n=15). ResultsThe 2 subunit had the most prominent expression level of the GABA-A receptor subunits in all samples. The and 2 subunits were up-regulated by pregnancy, whereas the epsilon subunit was more frequently expressed in healthy pregnant women than non-pregnant women who, in turn, commonly expressed the 6 and the 2 subunits. The 1 and epsilon subunits expression was altered by depression in pregnant women. The GABA-B1 receptor was up-regulated by depression in pregnant women, while the transporters NKCC1 and KCC4 were down-regulated by pregnancy. The changes recorded in the mRNA expression levels imply participation of GABA receptors in establishing and maintaining tolerance in pregnancy. Importantly, the correlation of mental health with the expression of specific receptor subunits reveals a connection between the immune cells and the brain. Biomarkers for mental health may be identified in PBMCs. ConclusionThe results demonstrate the impact gender, pregnancy and mental health have on the expression of GABA receptors and chloride transporters expressed in human PBMCs.
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| 8. |
- Barbe, Jeremy, et al.
(författare)
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Silicon nanocrystals on amorphous silicon carbide alloy thin films : Control of film properties and nanocrystals growth
- 2012
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 522, s. 136-144
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Tidskriftsartikel (refereegranskat)abstract
- The present study demonstrates the growth of silicon nanocrystals on amorphous silicon carbide alloy thin films. Amorphous silicon carbide films [a-Si1 − xCx:H (with x < 0.3)] were obtained by plasma enhanced chemical vapor deposition from a mixture of silane and methane diluted in hydrogen. The effect of varying the precursor gas-flow ratio on the film properties was investigated. In particular, a wide optical band gap (2.3 eV) was reached by using a high methane-to-silane flow ratio during the deposition of the a-Si1 − xCx:H layer. The effect of short-time annealing at 700 °C on the composition and properties of the layer was studied by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. It was observed that the silicon-to-carbon ratio in the layer remains unchanged after short-time annealing, but the reorganization of the film due to a large dehydrogenation leads to a higher density of SiC bonds. Moreover, the film remains amorphous after the performed short-time annealing. In a second part, it was shown that a high density (1 × 1012 cm− 2) of silicon nanocrystals can be grown by low pressure chemical vapor deposition on a-Si0.8C0.2 surfaces at 700 °C, from silane diluted in hydrogen. The influence of growth time and silane partial pressure on nanocrystals size and density was studied. It was also found that amorphous silicon carbide surfaces enhance silicon nanocrystal nucleation with respect to SiO2, due to the differences in surface chemical properties.
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