scholarly journals Shallow hot-point drill system for active layer temperature measurement along Zhongshan–Dome A traverse, Antarctica

2021 ◽  
pp. 1-9
Author(s):  
Yazhou Li ◽  
Xiaopeng Fan ◽  
Pavel G. Talalay ◽  
Yinke Dou ◽  
Siyu Lu ◽  
...  
Keyword(s):  
Penetration Rate ◽  
Temperature Sensors ◽  
Dome A ◽  
Zhongshan Station ◽  
System A ◽  
Field Season ◽  
The Mean ◽  
Borehole Temperature ◽  
Drill System ◽  
Mean Annual Air Temperature

Abstract In glaciology, snow–firn temperature at 10 m is considered a representation of the mean annual air temperature at the surface (MAAT) of the studied site. Although MAAT is an important parameter in ice-sheet investigations, it has not been widely measured in Antarctica. To measure the 10 m snow–firn temperature in Antarctica, a shallow hot-point drill system is designed. In this simple and lightweight system, a hot-point drill can melt boreholes with a diameter of 34 mm in the snow–firn to a depth of 30 m and a temperature sensors string can measure the borehole temperature precisely. In the 2018/19 field season, 16 boreholes along the Zhongshan–Dome A traverse were drilled, and the borehole temperature was measured. Although certain problems existed pertaining to the hot-point drill, a total depth of ~244 m was successfully drilled at an average penetration rate of ~10 m h−1. After borehole drilling, ~12–15 h were generally required for the borehole to achieve thermal equilibrium with the surroundings. Preliminary results demonstrated that the 10 m snow–firn temperature along the traverse route was affected by the increasing altitude and latitude, and it decreased gradually with an increase in the distance from Zhongshan station.

scholarly journals Spatial and temporal variability in isotope composition of recent snow in the vicinity of Vostok station, Antarctica: implications for ice-core record interpretation

2002 ◽  
Vol 35 ◽  
pp. 181-186 ◽  
Author(s):  
Alexey A. Ekaykin ◽  
Vladimir Ya. Lipenkov ◽  
Narcisse I. Barkov ◽  
Jean Robert Petit ◽  
Valerie Masson-Delmotte
Keyword(s):  
Isotope Composition ◽  
Ice Core ◽  
Snow Accumulation ◽  
Spatial And Temporal Variability ◽  
Weak Correlation ◽  
Ice Core Record ◽  
Vostok Station ◽  
The Mean ◽  
Mean Annual Air Temperature ◽  
Snow Samples

AbstractContinuous, detailed isotope (δD and δ18O) profiles were obtained from eight snow pits dug in the vicinity of Vostok station, Antarctica, during the period 1984– 2000. In addition, snow samples taken along the 1km long accumulation-stake profile were measured to determine spatial variability in isotope composition of recent snow. the stacked δD time series spanning the last 55 years shows only weak correlation with the mean annual air temperature recorded at Vostok station. Significant oscillations of both snow accumulation and snow isotope composition with the periods 2.5, 5, 20 and, possibly, ~102 years observed at single points are interpreted in terms of drift of snow-accumulation waves of various scales on the surface of the ice sheet.

scholarly journals The penetration of methanol into bovine cardiac and hepatic tissues is faster than ethanol and formalin

2018 ◽  
Author(s):  
Michelle Steicke ◽  
Guang Yang ◽  
Tam Nguyen Dinh ◽  
Matthew Dunster-Jones ◽  
Owen Sargisson ◽  
...  
Keyword(s):  
Liver Tissue ◽  
Penetration Rate ◽  
Biological Tissues ◽  
Heart Tissue ◽  
Penetration Distance ◽  
Before And After ◽  
Tissue Shrinkage ◽  
The Mean ◽  
Post Hoc ◽  
Liver Tissues

Methanol, ethanol and formalin are commonly used as fixatives to preserve biological tissues from decay in the preparation of histological sections. Fixation of the inner layers of the tissue depends on the ability of the fixative to diffuse into the tissue. It is unknown whether methanol penetrates tissues at similar rates to other fixatives. This study aimed to compare the penetration rates of methanol, ethanol and formalin into bovine heart and liver tissues. The penetration distance and tissue shrinkage or expansion were measured by analysing the digital images of tissue before and after immersion in different fixatives for 1, 2, 6 or 10 h. Data were analysed using two-way ANOVA, followed by Bonferroni’s post-hoc test. The penetration distance of methanol was significantly greater in both heart and liver tissues compared with that of ethanol (N=4, P<0.001). Methanol or ethanol immersion led to similar shrinkage of both tissues (P>0.05). The penetration rate of formalin was similar to that of ethanol in both tissues however it was significantly slower than methanol (N=4, P<0.005 in the heart; P<0.001 in the liver). The mean penetration coefficients of methanol, formalin and ethanol in the heart tissue were 2.609, 1.994 and 1.801, respectively, and 3.012, 2.153 and 2.113, respectively, in the liver tissue. The penetration coefficient of methanol was significantly greater than that of ethanol or formalin in both tissues (P<0.001 for each comparison). In conclusion, methanol penetrates tissue significantly faster than ethanol and formalin.

scholarly journals Soil temperature study in Puerto Rico

1969 ◽  
Vol 93 (3-4) ◽  
pp. 149-171
Author(s):  
Jorge L. Lugo-Camacho ◽  
Miguel A. Muñoz ◽  
Juan Pérez-Bolívar ◽  
Gregory R. Brannon
Keyword(s):  
Puerto Rico ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Sea Level ◽  
Air Temperature ◽  
Temperature Regime ◽  
Soil Series ◽  
Soil Temperature Regime ◽  
The Mean ◽  
Mean Annual Air Temperature

Soil temperature measurements from a climate monitoring network in Puerto Rico were evaluated and the difference between mean summer and mean winter soil temperature, known as isotivity value, was calculated. Air and soil temperature was collected from five weather stations of the USDA-Natural Resources Conservation Service from sea level to 1,019 m above sea level and from different soil moisture regimes. Isotivity values ranged from 1.2 to 3.9° C with an average of 2.6° C. The 750-m elevation was identified as the limit between the isohyperthermic and isothermic soil temperature regimes in the perudic soil moisture regime in Puerto Rico. The greatest differences between mean annual soil temperature and mean annual air temperature were observed at Guánica, Combate and Guilarte (2.1 ° C) stations. The smallest differences were observed at Maricao (0.8° C) and Isabela (1.8° C) stations. The study also indicated that the mean annual soil temperature in Puerto Rico can be estimated by adding 1.8° C to the mean annual air temperature or by the equation y = -0.007x + 28.0° C. The equation indicates that 97 percent of the time the behavior of the mean annual soil temperature is a function of elevation. According to the updated soil temperature regime boundaries, eight soil series were established in the Soil Survey of San Germán Area. In an area under the isothermic soil temperature regime, four soil series were classified as Oxisols (Haploperox), two soil series as Inceptisols (Eutrudepts) and two soil series as Mollisols (Argiudolls). This is the first field recognition of the Haploperox soil great group in the United States and its territories.

Multiple channel queues in heavy traffic. I

1970 ◽  
Vol 2 (01) ◽  
pp. 150-177 ◽  
Author(s):  
Donald L. Iglehart ◽  
Ward Whitt
Keyword(s):  
Heavy Traffic ◽  
Arrival Rate ◽  
Standard System ◽  
Interarrival Time ◽  
Service Rate ◽  
Service Channel ◽  
Multiple Channel ◽  
System A ◽  
The Mean ◽  
Service Channels

The queueing systems considered in this paper consist of r independent arrival channels and s independent service channels, where as usual the arrival and service channels are independent. Arriving customers form a single queue and are served in the order of their arrival without defections. We shall treat two distinct modes of operation for the service channels. In the standard system a waiting customer is assigned to the first available service channel and the servers (servers ≡ service channels) are shut off when they are idle. Thus the classical GI/G/s system is a special case of our standard system. In the modified system a waiting customer is assigned to the service channel that can complete his service first and the servers are not shut off when they are idle. While the modified system is of some interest in its own right, we introduce it primarily as an analytical tool. Let λ i denote the arrival rate (reciprocal of the mean interarrival time) in the ith arrival channel and μ j the service rate (reciprocal of the mean service time) in the jth service channel. Then is the total arrival rate to the system and is the maximum service rate of the system. As a measure of congestion we define the traffic intensity ρ = λ/μ.

scholarly journals Preliminary results of ionic concentrations in snow pits along the Zhongshan–Dome A traverse route, Antarctica

2004 ◽  
Vol 39 ◽  
pp. 155-160 ◽  
Author(s):  
Ren Jiawen ◽  
Sun Junying ◽  
Qin Dahe
Keyword(s):  
Major Ions ◽  
Concentration Profiles ◽  
Accumulation Rates ◽  
Dome A ◽  
Stable Oxygen Isotope ◽  
Zhongshan Station ◽  
Ionic Concentrations ◽  
Regional Trends ◽  
Stable Oxygen ◽  
A Site

AbstractDuring an inland traverse expedition along the route from Zhongshan station on the coast to Dome A (about 4200ma.s.l.; 1400 km from Zhongshan) in East Antarctica in 1998/99, three snow pits with a depth of 2.1–3.3m were sampled continuously. Snow pits were located at sites 800–1100km from the coast, with altitudes varying from 2850 to 3760 m. The samples were analyzed for stable oxygen isotope and major ions. Seasonal variations in δ18O are not clear, so initial dating was made through comparison of concentration profiles of major ions and then adjusted according to the visible stratigraphy. Generally, average ionic concentrations decrease with increasing altitude and hence distance from the coast, but NH4+ and Ca2+ have relatively high values at a site 1000 km inland. Ionic concentrations tend to increase with depth at lower altitudes, but the opposite is true at higher altitudes. Accumulation rates increase with depth at site DT401 (3760ma.s.l.; 1097 km from Zhongshan) and decrease at DT364 (3380ma.s.l.; 1022 km from Zhongshan) and DT263 (2850ma.s.l.; 820 km from Zhongshan), suggesting that differences in regional trends exist. In all snow pits, Na+ and Cl– concentration profiles have a very good positive correlation. Profiles of nssSO42– in the pits show quite different features. At 3760ma.s.l, no remarkable nssSO42– peaks can be distinguished, but one and three peak sets are quite striking at 3380 and 2850 m, respectively.

scholarly journals Identification of multiple natural and anthropogenic sources of dust in snow from Zhongshan Station to Dome A, East Antarctica

2018 ◽  
Vol 64 (248) ◽  
pp. 855-865 ◽  
Author(s):  
ZHIHENG DU ◽  
CUNDE XIAO ◽  
MINGHU DING ◽  
CHUANJIN LI
Keyword(s):  
Major Ions ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
East Antarctica ◽  
Anthropogenic Sources ◽  
Dome A ◽  
Long Distance ◽  
Anthropogenic Pollutants ◽  
Zhongshan Station ◽  
Snow Samples

ABSTRACTThe stable oxygen isotope composition, major ions and isotopic compositions of strontium (Sr), neodymium (Nd) and lead (Pb) in insoluble dust from recent surface snow samples along the transect from the Zhongshan and Progress stations (located on the Amery Ice Shelf, East Antarctica) to Dome A (Summit, Antarctica) were analysed. No previous isotopic fingerprinting studies have been conducted for this transect. These data were used to document the dust provenances in Antarctica along the transect up to the highest site, Dome A, for the first time. The insoluble dust in snow samples along the coast displays an overall crust-line isotopic signature that is characterised by highly radiogenic 87Sr/86Sr values and less radiogenic 143Nd/144Nd values. These signatures are comparable with those of samples collected near the ice-free areas of the Zhongshan and Progress stations. Spatial differences are statistically significant along the transect, and the Sr, Nd and Pb isotope components in insoluble dust from two continuous snow samples at Dome A exhibit marked differences, indicating that additional dust reaches the East Antarctic Plateau. The isotopic characteristics of insoluble dust from this transect indicate that the long-distance natural dust and anthropogenic pollutants in these samples primarily originate from Australia.

scholarly journals A Flow-Calibrated Method to Project Groundwater Infiltration into Coastal Sewers Affected by Sea Level Rise

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1934
Author(s):  
Adrienne Fung ◽  
Roger Babcock
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Monitoring Data ◽  
Groundwater Levels ◽  
Flow Monitoring ◽  
System A ◽  
Coastal Cities ◽  
The Mean ◽  
Groundwater Infiltration

Collection systems in coastal cities are often below the groundwater table, leading to groundwater infiltration (GWI) through defects such as cracks and poor lateral connections. Climate-change-induced sea level rise (SLR) will raise groundwater levels, increasing the head and thus the inflow. A method has been developed to predict GWI when groundwater levels change using calibration with sewershed flow monitoring data. The calibration results in a parameter that characterizes the porosity of the collection system. A case study is presented for a coastal city with reliable flow monitoring data for eight days that resulted in a large range of effective defect sizes (minimum 0.0044 to maximum 0.338 radians), however, the range of predicted future GWI in currently submerged pipes varied by only 12% from the mean. The mean effective defect predicts 70 to 200% increases in GWI due to SLR of 0.3 to 0.9 m (1 to 3 ft), respectively, for currently submerged pipes. Predicted additional GWI for pipes that will become submerged due to SLR will increase GWI to values that approach or exceed the current average dry weather flow. This methodology can be used for planning of infrastructure improvements to enhance resiliency in coastal communities.

ABOUT THE MEAN KING'S PROBLEM AND DISCRETE WIGNER DISTRIBUTIONS

2006 ◽  
Vol 20 (11n13) ◽  
pp. 1742-1760 ◽  
Author(s):  
THOMAS DURT
Keyword(s):  
Weyl Function ◽  
Galois Field ◽  
Bell States ◽  
Quadratic Extensions ◽  
System A ◽  
Wigner Distributions ◽  
Particular Solution ◽  
The Mean ◽  
One To One ◽  
Adjoint Operators

When the state of a quantum system belongs to a N-dimensional Hilbert space, with N the power of a prime number, it is possible to associate to the system a finite field (Galois field) with N elements. In this paper, we introduce generalized Bell states that can be intrinsically expressed in terms of the field operations. These Bell states are in one to one correspondence with the N2elements of the generalised Pauli group or Heisenberg-Weyl group. This group consists of discrete displacement operators and provides a discrete realisation of the Weyl function. Thanks to the properties of generalised Bell states and of quadratic extensions of finite fields, we derive a particular solution for the Mean King's problem. This solution is in turn shown to be in one to one correspondence with a set of N2self-adjoint operators that provides a discrete realisation of the Wigner quasi-distribution.

Analysis of an Artificial Ventricle and Mock Circulatory System

1977 ◽  
Vol 99 (4) ◽  
pp. 184-188 ◽  
Author(s):  
K. M. High ◽  
J. A. Brighton ◽  
A. D. Brickman ◽  
W. S. Pierce
Keyword(s):  
Artificial Heart ◽  
Circulatory System ◽  
Experimental Tests ◽  
Mean Flow ◽  
Actual System ◽  
Mock Circulatory System ◽  
System A ◽  
The Mean ◽  
Artificial Ventricle ◽  
Good Agreement

A mathematical model is developed for calculating the pressures and flows in an artificial heart, its pneumatic drive unit, and a mock circulatory system. The system is divided into convenient subsystems to facilitate the analysis, and each subsystem is then analyzed separately. The set of independent equations developed is solved on a computer and corresponding experimental tests are made on the actual system. A comparison of the experimental and computer results shows good agreement for the mean flow rate through the pump and also for several instantaneous pressures and flow rates in the system.

Spatial Prediction of Soil Temperature in China

2014 ◽  
Vol 955-959 ◽  
pp. 3718-3723
Author(s):  
Hui Zhi Zhang ◽  
Xue Zheng Shi
Keyword(s):  
Soil Temperature ◽  
Spatial Patterns ◽  
Air Temperature ◽  
Ordinary Kriging ◽  
Spatial Prediction ◽  
Regression Kriging ◽  
Auxiliary Variables ◽  
Geostatistical Methods ◽  
The Mean ◽  
Mean Annual Air Temperature

Temperature affects many soil biochemical and geochemical processes. The growth of plants, seed germination, circulations of carbon and nitrogen are all significantly influenced by soil temperature, thus it is important to estimate the spatial pattern of soil temperature. This paper shows the results of spatial patterns of mean annual soil temperature interpolated from the measurements of 698 meteorological stations in China. Four geostatistical methods, ordinary kriging (OK), regression kriging with mean annual air temperature (RK-1), regression kriging with latitude, longitude and elevation (RK-2) and regression kriging with multi-auxiliary predictors (RK-3), were compared. Ordinary kriging (OK) directly interpolated the mean annual soil temperature data extracted from meteorological stations to obtain the spatial patterns of the mean annual soil temperature. For the three regression kriging methods, intensive auxiliary variables (mean annual air temperature, elevation, latitude and longitude), which were correlated with mean annual soil temperature, were used to increase the accuracy of estimation. The results suggested that RK-3 preformed best, followed by RK-1 and RK-2. The intensive data of auxiliary variables used in the regression kriging significantly improved the accuracy of interpolation results.

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