A step towards the final frontier: Lessons learned from acceptance testing of the first HPE/Cray EX 3000 system at ORNL

In this article, we summarize the deployment of the Air Force Weather (AFW) HPC11 system at Oak Ridge National Laboratory (ORNL) including the process followed to successfully complete acceptance testing of the system. HPC11 is the first HPE/Cray EX 3000 system that has been successfully released to its user community in a federal facility. HPC11 consists of two identical 800-node supercomputers, Fawbush and Miller, with access to two independent and identical lustre parallel file systems. HPC11 is equipped with Slingshot 10 interconnect technology and relies on the HPE Performance Cluster Manager software for system configuration. ORNL has a clearly defined acceptance testing process used to ensure that every new system deployed can provide the necessary capabilities to support user workloads. We worked closely with HPE and AFW to develop a set of tests that used the United Kingdom's Meteorological Office's Unified Model and 4-dimensional variational data assimilation. We also included benchmarks and applications from the Oak Ridge Leadership Computing Facility portfolio to fully exercise the HPE/Cray programming environment and evaluate the functionality and performance of the system. Acceptance testing of HPC11 required parallel execution of each element on Fawbush and Miller. In addition, careful coordination was needed to ensure successful acceptance of the newly deployed lustre file systems alongside the compute resources. In this work, we present test results from specific system components and provide an overview of the issues identified, challenges encountered, and the lessons learned along the way.     

Neue Entwicklungen in der Galvanotechnik

New Developments in Electroplating Electrodeposited composite coatings are well known for wear reduction or friction reducing applications. A new development are microcapsules containing composite coatings. Microcapsules have a solid, liquid or gaseous core with a shell from different plastics with a diameter from 0.3 up to 50 μm. Self lubricating coatings, for example, are able to reduce the coefficient of friction from 0.7 to 0.1 (Nickel vs. steel). Wear‐indicating coatings containing micro‐encapsulated perfumes, fluorescent dyes or other detectable substances were developed. New processes for the electroplating on light metals are developed. These coatings are more corrosion resistant than the commercially available layers. The increased corrosion resistance results either by the embedding of encapsulated inhibitors in an interlayer or by an electrically non‐conducting interlayer which separates coating and substrate.     

Influence of the heating temperature on the fat composition of milk fat with emphasis on cis-/trans-isomerization

Milk fats from barn and pasture feeding (WMF and SMF) were analysed for changes in the content of fatty acids, triglycerides and cholesterol after 15-minute heating at 200, 225, 250, 275 and 300°C, respectively. The lower temperatures of 200 and 225°C are realistic in cooking and frying processes, whereas temperatures of 250 to 300°C were chosen to show the effects of overheating the fat. The main focus was put on identification and quantitation of individual isomers of C18 : 1 (trans δ4, δ5 to δ16, cis δ9 to δ15) as well as of C18 : 2 including the conjugated linoleic acid (CLA) isomer cis δ9, trans δ11. The trans isomers among these fatty acids are of great importance as regards nutritional physiology. Furthermore, determinations of the content of α-tocopherol and of free fatty acids as well as of the iodine and peroxide value were performed. Primarily, with rising temperature there was an increase of the elaidic acid (trans δ9) content from 0.3% to 0.5% (WMF) and from 0.2% to 0.7% (SMF) between the base fat and 300°C, whereas in this range the vaccenic acid (trans δ11) content decreased from 1.1% to 0.9% (WMF) and from 3.8% to 3.4% (SMF). The other trans-C18 : 1 isomers as well as the cis isomers δ12 to δ15 exhibited no general trend at these temperatures. The content of oleic acid strongly decreased with the WMF (max. 2.90%), whereas there was no comparable decrease with the SMF (max. 0.48%). This effect possibly was attributable to the content of α-tocopherol being higher by relatively 71% in the SMF. At the higher temperatures particularly strong decreases (base fat → 300°C) were found for cis δ9, cis δ12, trans δ11, cis δ15, cis δ9, trans δ11 (CLA) and linoleic acid (WMF: 1.55 → 0.67%, 0.17 → 0.09%, 0.50 → 0.03%, 0.42 → 0.06%; SMF: 1.05 → 0.67%, 0.54 → 0.38%, 1.71 → 0.35%, 0.61 → 0.17%). All together, absolute losses of fatty acids amounted to max. 4.6% and 6.5% (SMF and WMF, resp.). As losses of linoleic and linolenic acids were not compensated by formation of isomerization products, formation of oxidation products possibly having a high health-threatening potential must have taken place to a greater extent. On the other hand, a great part of these oxidation products are volatile and their amount in the remaining fat was not recorded by the analytical method applied. Anyway, isomerization and oxidation are low at 200°C, but these undesirable effects strongly increase with higher temperatures.     

C18 : 1, C18 : 2 and C18 : 3 trans and cis fatty acid isomers including conjugated cis δ9,trans δ11 linoleic acid (CLA) as well as total fat composition of German human milk lipids

In particular with respect to infant nutrition knowledge of the current contents of trans fatty acids (TFA) and of conjugated linoleic acid (CLA) in human milk lipids is of interest. After pre-separation by Ag-TLC 11 trans-C18 : 1 isomers could be quantified by GC with a mean total content of 2.40 ± 0.60 wt% in samples from 40 German women. For the positional isomers t4, t5, t6–8, t9, t10, t11, t12, t13, t14, t15 and t16 contents of 0.02, 0.02, 0.21, 0.37, 0.32, 0.68, 0.23, 0.15, 0.18, 0.09 and 0.14 wt% were established, with vaccenic acid being the predominant isomer. Further, small trans-C14 : 1 and trans-C16 : 1 contents of 0.08% and 0.15% on average were found. As the trans-C18 : 1 isomers also the trans-C16 : 1 isomers of human milk lipids could for the first time be baseline-resolved by GC to a great extent. Moreover, besides a mean CLA (c9,t11) content of 0.40 ± 0.09% further 6 cis/trans isomers of linoleic acid with a total content of 1.07 ± 0.56% on average (w/o CLA) were determined. Further, 4 trans isomers of α-linolenic acid could be baseline-resolved exhibiting a total content of 0.11%. Altogether German human milk lipids on average were found to contain 3.81 ± 0.97% TFA with a range of 2.38–6.03%. Direct connections between the dietary intake of trans-C18 : 1 isomers and the composition of human milk lipids could be established. The major fatty acids exhibited the following contents (wt%): C4: 0.16, C6: 0.18, C8: 0.06, C10: 0.58, C12: 3.12, C14: 6.43, C16: 25.28, C18: 7.41, C18 : 1 (total): 33.67, C18 : 2 (total): 10.63 and α-C18 : 3: 0.87.     

Series-system reliability-estimation using very small binomialsamples

This investigation explored the effect of incorporating prior information into series-system reliability estimates, where the inferences are made using very small sets (less than 10 observations) of binomial test-data. To capture this effect, the performance of a set of Bayes interval estimators was compared to that of a set of classical estimators over a wide range of subsystem beta prior-distribution parameters. During a Monte Carlo simulation, the Bayes estimators tended to provide shorter interval estimators when the mean of the prior system-reliability differed from the true reliability by 20 percent of less, but the classical estimators dominated when the difference was greater. Based on these results, the authors conclude that there is no clear advantage to using Bayes interval estimation for sample sizes less than 10 unless the poor mean system reliability is believed to be within 20 percent of the true system reliability. Otherwise, the Lindstrom-Madden estimator, a useful classical alternative for very small samples, should be used     

An assessment of selenium to mercury in Greenland marine animals

Information on mercury and selenium molar relation in muscle, liver and kidney tissue of Greenland marine animals is presented. In the majority of the samples selenium was present in a molar surplus to mercury. This was most clear in molluscs, crustaceans, fish and seabirds. A 1:1 molar ratio was found in tissues of marine mammals with high mercury concentrations (above approx. 10 nmol/g). This was most clearly demonstrated for liver and kidney tissue of polar bear and for ringed seal with high mercury concentration in the liver. These findings support previous results found in liver tissue of marine mammals, suggesting that methyl mercury is detoxified by a chemical mechanism involving selenium. If the anthropogenic release of mercury to the environment increases in the future due to increasing energy demands, species such as polar bears and seals with high tissue mercury concentrations should be monitored to elucidate whether this protective mechanism can be maintained in target organs.     

Lead, cadmium, mercury and selenium in Greenland marine biota and sediments during AMAP phase 1

Lead, cadmium, mercury and selenium levels in the Greenland marine environment from the first phase of the AMAP are presented. Samples were collected in 1994-1995 covering four widely separated regions in Greenland. Samples included sediments, soft tissue of blue mussel; and liver of polar cod, shorthorn sculpin, glaucous gull, Iceland gull and ringed seal. Concentrations of lead were found to increase with the size of blue mussel, but not with the age of gulls or ringed seal. Both cadmium and mercury concentrations were found to increase with the size/age of all species. Selenium concentrations decreased with increasing size of blue mussel, but increased with the age of gulls and ringed seal. Element levels found are within the range of those found in previous studies in Greenland. Relative to global background levels, lead levels must be considered low, whereas levels of cadmium, mercury and selenium in Greenland marine biota are high. Significant differences in element levels in sediments and biota among regions in Greenland were seen in several cases. There was a tendency for the highest lead and mercury concentrations to be found in east Greenland, whereas the highest cadmium concentrations were found in central west Greenland. However, the geographical differences among the media did not show a consistent pattern.     

Contribution of Solutes to Density Stratification in a Meromictic Lake (Waldsee/Germany)

Density differences are the key parameter for stratification stability. We used data from the iron-meromictic Waldsee, Germany, a lignite mine pit lake, to quantify the contribution of single solutes to water density and analyzed the density gradient. Iron meromictic lakes maintain their density gradient through chemical reactions. Hence, quantifying the contributions of separate solutes is essential for understanding the entire process. Based on solute concentrations and literature values of partial molal volumes, substance specific density contributions were quantitatively evaluated. Then, by direct measurements of the density of IHSS Waskish peat fulvic acid, we quantified the density contribution of dissolved organic carbon (DOC). While several solutes contributed to the density throughout the water column, only those substances that occurred at higher concentrations in the anoxic monimolimnion than in the oxic mixolimnion were crucial to sustaining the density difference between the two layers. In Waldsee, the density difference between monimolimnion and mixolimnion was attributed to dissolved Fe²⁺ (0.23?g/L, resulting in a 45?% of the density difference due to solutes) and to the carbonate system (HCO₃ ^?, about 0.16?g/L and CO₂, 0.03?g/L) while Ca²⁺ and DOC delivered only a small contribution. In summer, total density differences were dominated by temperature differences; during winter, solutes sustained meromixis. Finally, we present a complete list of specific density fractions for basically all of the density-relevant substances in fresh waters.     

Levels and spatial and temporal trends of contaminants in Greenland biota: an updated review

Knowledge of contaminant levels in Greenland biota has increased substantially in recent years, particularly for persistent organic pollutants. This paper reviews and updates knowledge of spatial and temporal trends of Cd, Hg and organochlorines (PCBs, DDTs, HCHs, HCB and chlordane-related compounds) in Greenland terrestrial, freshwater and marine biota. The most comprehensive studies of spatial trends of Cd and Hg in the terrestrial ecosystem concern lichens, with relatively complete coverage, and caribou (Rangifer tarandus), with coverage mainly in different regions of central West Greenland and Southwest Greenland. The Arctic char (Salvelinus alpinus) is the only freshwater organism for which studies of spatial trends of Hg levels have been completed. Information on spatial trends of Cd and Hg in the marine environment is available from studies of fish, seabirds, ringed seals (Phoca hispida) and polar bears (Ursus maritimus). Geographical patterns of Cd and Hg in Greenland biota were not always consistent among different species or different studies. In landlocked Arctic char the concentrations of Hg decreased from south to north. In marine animals levels of Hg tended to be higher in East Greenland than in West Greenland and Cd levels were highest in biota from Disko Island in central West Greenland. The observed regional differences are difficult to explain but in most cases the causes appear to be natural rather than anthropogenic. Only a few time series covering the last 20 years exist for Cd and Hg. The one time series indicating a temporal change is for ringed seals in Northwest Greenland, which shows an increasing trend of Hg and a decreasing trend of Cd since 1984. Whether the changes reflect anthropogenic inputs, seal behaviour or other environmental factors is unknown. The most significant new insights have concerned organochlorines. In general, levels of these compounds were very low in terrestrial biota compared to marine species. Concentrations in landlocked Arctic char were highest in Southeast Greenland and lowest in Northwest and Northeast Greenland. Marine species from East Greenland had consistently higher levels of SigmaPCB, SigmaDDT and SigmaHCH than marine species from West Greenland. Very few data exist to evaluate temporal changes of organochlorine levels in Greenland biota, and this is the most significant knowledge gap at present. The most pronounced change observed was a decrease of 78% in SigmaPCB levels in polar bears from East Greenland from 1990 to 2000. Levels of SigmaHCH in shorthorn sculpins (Myoxocephalus scorpius) and seals from both central West Greenland and central East Greenland appear to have decreased since 1994. Increasing trends of SigmaDDT from 1994 until now were found in both sexes of seals as well as in male sculpins from central West Greenland.     

Cortisol levels in hair of East Greenland polar bears

To demonstrate the ability to assess long-term hypothalamic-pituitary-adrenocortical (HPA) axis activity in polar bears (Ursus maritimus), a pilot study was conducted in which cortisol concentrations was analyzed in hair from 7 female (3-19 years) and 10 male (6-19 years) East Greenland polar bears sampled in 1994-2006. The hair was chosen as matrix as it is non-invasive, seasonally harmonized, and has been validated as an index of long-term changes in cortisol levels. The samples were categorized according to contamination: eight were clean (2 females, 6 males), 5 had been contaminated with bear blood (2 F, 3 M), and 4 with bear fat (3 F, 1 M). There was no significant difference in cortisol concentration between the three categories after external contamination was removed. However, contaminated hair samples should be cleaned before cortisol determination. Average hair cortisol concentration was 8.90 pg/mg (range: 5.5 to 16.4 pg/mg). There was no significant correlation between cortisol concentration and age (p = 0.81) or sampling year (p = 0.11). However, females had higher mean cortisol concentration than males (females mean: 11.0 pg/mg, males: 7.3 pg/mg; p = 0.01). The study showed that polar bear hair contains measurable amounts of cortisol and that cortisol in hair may be used in studies of long-term stress in polar bears.