Equivalent Depth Research Articles

SU‐E‐T‐198: Comparison Between a PTW MicroDiamond Dosimeter and a Markus Chamber in a 62 MeV/n Carbon Ion Beam

Purpose:To investigate the linear energy transfer (LET) dependence of a PTW Freiburg microDiamond dosimeter, we compared its response to the response of a plane‐parallel Markus chamber in a 62 MeV/n mono‐energetic carbon ion beam.Methods:The response of both detectors has been studied as a function of depth in graphite by adding or removing graphite plates in front of the detectors. To account for fluctuations of the beam, we used two setups with different monitor chambers. The depth of the effective point of measurement of both detectors has been converted into a graphite equivalent depth using ICRU Report 73 data. As recommended by IAEA TRS‐398, the response of the Markus chamber has been corrected for temperature, pressure, polarity effects and ion recombination. The latter required an additional experiment; to quantify the effect of volume recombination and initial recombination, measurements have been performed at different voltages and different dose rates.Results:As expected, the dominant process leading to ion recombination for carbon ion beam is the initial recombination. At the entrance, the ion recombination correction equals 1.1% and the value is approximately constant in the plateau region. Due to the increase of the LET in the Bragg peak region, we observe a strong increase of the ion recombination correction, up to 6.1% at the distal edge. Comparison between the microDiamond response and the Markus chamber response shows good agreement in the plateau region. However, we observe a 13.6% under response of the microDiamond in the Bragg peak.Conclusion:Increasing between 1% and 6%, the depth dependent ion recombination correction has to be applied to the Markus response. The comparison between the microDiamond and the Markus chamber indicates that there is an under‐response of the microDiamond in the vicinity of the Bragg peak due to the increased LET.

How much can we gain with increasing model complexity with the same model concepts?

Summary The main purpose of this study is to test the hypothesis that, with appropriate structures, increasing model complexity with the same model concepts would lead to an increase in the model efficiency in simulating either runoff or internal variables. Five variants of the Hydrologiska Byrans Vattenbalansavdelning (HBV) model, i.e. a lumped model (LWhole), a semi-distributed model (SBand), a grid-model without routing (GRZero), a grid-model with hillslope routing (GROne), and a grid-model with both hillslope and channel routing (GRTwo) are compared in a cold and mountainous catchment in central southern Norway. The five models are compared with respects to (1) runoff simulation at the catchment outlet and the interior points, and (2) simulations of internal variables, i.e. evapotranspiration, snow water equivalent and groundwater depth. The results show that the models with higher complexity can improve the runoff simulation both at the catchment outlet and the interior points. However, there is no superiority of complex grid-models over simple grid-models in reproducing internal variables in this study.

Freshwater Flux and Spatiotemporal Simulated Runoff Variability into Ilulissat Icefjord, West Greenland, Linked to Salinity and Temperature Observations near Tidewater Glacier Margins Obtained Using Instrumented Ringed Seals

AbstractThe distribution of terrestrial surface runoff to Ilulissat Icefjord, west Greenland, is simulated for the period 2009–13 to better emphasize the spatiotemporal variability in freshwater flux and the link between runoff spikes and observed hydrographic conditions at the Greenland Ice Sheet tidewater glacier margins. Runoff model simulations were forced with automatic weather station data and verified against snow water equivalent depth, equilibrium line altitude, and quasi-continuous salinity and temperature observations obtained by ringed seals. Instrumented seals provide a novel platform to examine the otherwise inaccessible waters beneath the dense ice mélange within the first 0–10 km of the calving front. The estimated mean freshwater flux from land was 70.6 ± 4.2 km3 yr−1, with an 85% contribution of ice discharge from Jakobshavn Isbrae (also known as Sermeq Kujalleq), 14% from runoff, and the remaining 1% from precipitation on the fjord surface area, subglacial geothermal melting, and frictional melting due to basal ice motion. Runoff was simulated to be present from May to November and to vary spatially according to glacier cover and individual catchment size. Salinity and temperature observations correlate (significantly) with simulated runoff for the upper part of both the main fjord and southern fjord arm. Also, at the tidewater glacier margins in the northern and southern arm of Ilulissat Icefjord, salinity changes in the upper water column (upper 50 m) are significant after temporal spikes in runoff during late summer, while small-amplitude runoff variability during the recession of runoff did not create a clear signal in observed salinity variability. Also, in the southern arm near the glacier margin (between 100- and 150-m depth), the heterogeneous distribution in salinity could be because of the mixing of meltwater going upward from passing the grounding line. The effect of runoff spikes on observed salinity is less pronounced near the ice margin of Jakobshavn Isbrae than in the north and south arms.

Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures.

The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures. The calibration and reproducibility of the MOSkin detector and its dependency on different radiation beam qualities were carried out using RQR standard radiation qualities in free-in-air geometry. Studies of the other characterization parameters, such as the dose linearity and dependency on exposure angle, field size, frame rate, depth-dose, and source-to-surface distance (SSD), were carried out using a solid water phantom under a clinical x-ray unit. The MOSkin detector showed good reproducibility (94%) and dose linearity (99%) for the dose range of 2 to 213 cGy. The sensitivity did not significantly change with the variation of SSD (± 1%), field size (± 1%), frame rate (± 3%), or beam energy (± 5%). The detector angular dependence was within ± 5% over 360° and the dose recorded by the MOSkin detector in different depths of a solid water phantom was in good agreement with the Markus parallel plate ionization chamber to within ± 3%. The MOSkin detector proved to be reliable when exposed to different field sizes, SSDs, depths in solid water, dose rates, frame rates, and radiation incident angles within a clinical x-ray beam. The MOSkin detector with water equivalent depth equal to 0.07 mm is a suitable detector for in vivo skin dosimetry during interventional radiology procedures.

Coercivity enhancements of Nd–Fe–B sintered magnets by diffusing DyHx along different axes

Diffusing heavy rare earth elements along the grain boundaries (GBs) for Nd2Fe14B-type sintered magnets serves as an effective method to enhance coercivity and to minimize remanence loss simultaneously. Considering the texture anisotropy of Nd-rich GB phases, the coercivity incremental difference by diffusing DyHx fine powders along or perpendicular to the <0 0 1 > easy axis (c-axis) has been investigated. The coercivity increases more rapidly to 20.61 kOe (5.76 kOe higher than that of the as-sintered state) when diffusing along the c-axis than that diffusing perpendicular to c-axis (18.85 kOe, 4.00 kOe higher than the as-sintered state). Microstructural investigation reveals that Dy diffuses more easily towards the magnet inner part when treating along the c-axis than that for the perpendicular case due to the anisotropic distribution of the Nd-rich phase. This is verified by a higher Dy content at equivalent diffusing depth and a much deeper final diffusion distance. The local Dy-containing fractions with a stronger anisotropy field are richer for the magnet treated along the c-axis, leading to the much rapider coercivity enhancement. This work reveals that diffusion heavy rare earth along the c-axis is more effective to enhance coercivity for aligned Nd–Fe–B sintered magnets.

Cerebrovascular reactivity to carbon dioxide under anesthesia: a qualitative systematic review.

Controlling the arterial carbon dioxide tension (PaCO2) to reduce the cerebral blood flow (CBF) and the intracranial pressure is a common practice in neuroanesthesia. A change in CBF in response to change in PaCO2 is termed as cerebrovascular reactivity to carbon dioxide (CVR-CO2). Studies have shown that, both inhalational and intravenous anesthetic agents have variable effects on CVR-CO2 and the effect of anesthetic agents on CVR also varies with many physiological and pathologic conditions. The objectives of this review were to evaluate the effect of anesthetic agents on the CVR-CO2 in adults and to determine how this response is modified by other physiological and pathologic factors. We conducted a systematic search of the databases of Medline, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews using related term components for both CVR-CO2 and anesthesia. Our primary outcome of this review was to determine whether the CVR-CO2 is maintained under anesthesia. The other endpoints of this review are to determine the effect of other factors (age, sex, medical comorbidities, and cerebrovascular pathology) on the CVR-CO2 under anesthesia. Because of the methodological heterogeneity in the primary studies, quantitative analysis of the data was not possible, and therefore, we have summarized the data qualitatively. Our search strategy yielded 1356 citations. After excluding nonpertinent papers, 38 studies were included for the systematic review. Nineteen randomized controlled trials and 19 observational studies met inclusion criteria and a total of 793 patients were studied. Transcranial Doppler was the most commonly used method for measuring CBF and changing the respiratory rate and/or minute ventilation were the most commonly used method to change the CO2 tension. CVR-CO2 is maintained with both inhalational and intravenous anesthetic agents within the range of concentrations used in clinical anesthesia. At doses leading to a broadly equivalent depth of anesthesia, the reactivity value was highest with isoflurane and the least with propofol. Individual agents differ in their degree of reactivity to hypercapnic and hypocapnic stimuli. CVR-CO2 is impaired in elderly patients when compared with young patients with both sevoflurane and propofol anesthesia. In patients with medical comorbidities, the CVR-CO2 impairment under anesthesia was associated with the severity of the underlying diseases and not the anesthetic agents. Our systematic review showed that within the clinical anesthesia concentrations, CVR-CO2 is maintained under both propofol and inhalational agents. However, most of the information available is from non-neurosurgical patients and these studies also suffer from significant methodological heterogeneity. Therefore, we were limited by the amount and the quality of data available for this review.

Dynamic-stochastic modeling of snow cover formation on the European territory of Russia

A dynamic-stochastic model, which combines a deterministic model of snow cover formation with a stochastic weather generator, has been developed. The deterministic snow model describes temporal change of the snow depth, content of ice and liquid water, snow density, snowmelt, sublimation, re-freezing of melt water, and snow metamorphism. The model has been calibrated and validated against the long-term data of snow measurements over the territory of the European Russia. The model showed good performance in simulating time series of the snow water equivalent and snow depth. The developed weather generator (NEsted Weather Generator, NewGen) includes nested generators of annual, monthly and daily time series of weather variables (namely, precipitation, air temperature, and air humidity). The parameters of the NewGen have been adjusted through calibration against the long-term meteorological data in the European Russia. A disaggregation procedure has been proposed for transforming parameters of the annual weather generator into the parameters of the monthly one and, subsequently, into the parameters of the daily generator. Multi-year time series of the simulated daily weather variables have been used as an input to the snow model. Probability properties of the snow cover, such as snow water equivalent and snow depth for return periods of 25 and 100 years, have been estimated against the observed data, showing good correlation coefficients. The described model has been applied to different landscapes of European Russia, from steppe to taiga regions, to show the robustness of the proposed technique.

SHALLOW CAVITIES IN MULTIPLE-PLANET SYSTEMS

Large cavities are often observed in protoplanetary disks, which might suggest the presence of planets opening gaps in the disk. Multiple planets are necessary to produce a wide cavity in the gas. However, multiple planets may also be a burden to the carving out of very deep gaps. When additional planets are added to the system, the time-dependent perturbations from these additional satellites can stir up gas in the gap, suppressing cavity opening. In this study, we perform two-dimensional numerical hydro calculations of gap opening for single and multiple planets, showing the effect that additional planets have on the gap depths. We show that multiple planets produce much shallower cavities than single planets, so that more massive planets are needed in the multiple-planet case to produce an equivalent gap depth as in the single-planet case. To deplete a gap by a factor of 100 for the parameters chosen in this study, one only requires $M_p \approx 3.5M_J$ in the single-planet case, but much more massive planets, $M_p \approx 7M_J$ are required in the multiple-planet case. This requirement of high-mass planets implies that such planets may be detectable in the next generation of direct imaging projects, in gaps whose depths are constrained to be sufficiently deep by ALMA.

Cardiovascular function during maintenance of anaesthesia with isoflurane or alfaxalone infusion in greyhounds experiencing blood loss

ObjectiveTo compare adequacy of oxygen delivery and severity of shock during maintenance of anaesthesia with isoflurane or alfaxalone infusion in greyhounds experiencing blood loss. Study designProspective, randomised study. AnimalsTwenty-four greyhounds (ASA I). MethodsAll greyhounds were premedicated with methadone (0.2 mg kg−1) intramuscularly. Anaesthesia was induced with alfaxalone 2.5 mg kg−1intravenously. Following endotracheal intubation, the dogs were connected to an anaesthetic circle circuit delivering oxygen. Dogs were allocated to receive inhaled isoflurane or an intravenous infusion of alfaxalone for maintenance of anaesthesia. Isoflurane was initially administered to achieve an end-tidal concentration of 1.4% and alfaxalone was initially administered at 0.13 mg kg−1 minute−1. The dose of isoflurane or alfaxalone was adjusted during instrumentation to produce a clinically equivalent depth of anaesthesia. All dogs were mechanically ventilated to normocapnia (PaCO2 35–40 mmHg; 4.67–5.33 kPa). Passive warming maintained core body temperature between 37 and 38 °C. Measured and calculated indices of cardiovascular function, including mean arterial blood pressure (MAP), cardiac index (CI), systemic vascular resistance index (SVRI), oxygen delivery index ( D˙O2I), oxygen consumption index ( V˙O2I) and oxygen extraction ratio (OER), were determined at baseline (60 minutes after start of anaesthesia) and after removal of 32 mL kg−1and 48 mL kg−1of blood. ResultsIn all dogs, blood loss resulted in a significant decrease in MAP, CI, D˙O2, and a significant increase in SVRI, V˙O2I, and OER. The changes in each of the indices did not differ significantly between dogs receiving isoflurane and dogs receiving alfaxalone. Conclusion and clinical relevanceNo difference in oxygen delivery or severity of shock was observed when either inhaled isoflurane or intravenous alfaxalone infusion was used for maintenance of anaesthesia in greyhounds experiencing blood loss. There appears to be no clinical advantage to choosing one anaesthetic agent for maintenance of anaesthesia over the other in a dog experiencing blood loss.

Predicting Equivalent Static Density of Fuzzy Ball Drilling Fluid by BP Artificial Neutral Network

A back-propagation artificial neutral network model is built based on 220 groups of PVT experimental data to predict the equivalent static density versus depth for fuzzy ball drilling fluid which is a kind of gas-liquid two-phase material. The model is applied in the Mo80-C well located in Sichuan Province of China; the maximum relative error between calculated results and measured data is less than 2%. By comparing with the multiple regression model, the present model has a higher precision and flexibility. The equivalent static density of fuzzy ball drilling fluid from ground to the depth of 6000 m is predicted by the present model, and the results show that the equivalent static density of fuzzy ball drilling fluid will decrease slowly with the growth of depth, which indicates that the gas cores of the fuzzy balls still can exist as deep as 6000 m.

Monte Carlo Simulation of the Carbon Beam Nozzle for the Biomedical Research Facility in RAON

‡§ The purpose of the Monte Carlo simulation study was to provide the optimized nozzle design to satisfy the beam conditions for biomedical researches in the Korean heavy-ion accelerator, RAON. The nozzle design was required to produce C 12 beam satisfying the three conditions; the maximum field size, the dose uniformity and the beam contamination. We employed the GEANT4 toolkit in Monte Carlo simulation to optimize the nozzle design. The beams for biomedical researches were required that the maximum field size should be more than 15×15 cm 2 , the dose uniformity was to be less than 3% and the level of beam contamination due to the scattered radiation from collimation systems was less than 5% of total dose. For the field size, we optimized the tilting angle of the circularly rotating beam controlled by a pair of dipole magnets at the most upstream of the user beam line unit and the thickness of the scatter plate located downstream of the dipole magnets. The values of beam scanning angle and the thickness of the scatter plate could be successfully optimized to be 0.5o and 0.05 cm via this Monte Carlo simulation analysis. For the dose uniformity and the beam contamination, we introduced the new beam configuration technique by the combination of scanning and static beams. With the combination of a central static beam and a circularly rotating beam with the tilting angle of 0.5 o to beam axis, the dose uniformity could be established to be 1.1% in 15×15 cm 2 sized maximum field. For the beam contamination, it was determined by the ratio of the absorbed doses delivered by C 12 ion and other particles. The level of the beam contamination could be achieved to be less than 2.5% of total dose in the region from 5 cm to 17 cm water equivalent depth in the combined beam configuration. Base d on the results, we could establish the optimized nozzle design satisfying the beam conditions which were required for biomedical researches.

Bulk electrical conductivity as an indicator of spatial distribution of nitrogen and phosphorous at feedlots

The increasing demands of producing beef for domestic and international consumption is leading to the development of feedlots in Argentina. Unfortunately, the great amount of manure produces leachate of nitrates and other ions which may affect groundwater quality. The objective of this paper was to identify the spatial distribution of bulk electrical conductivity (ECb) of non-saturated zone and its association with variability of nitrates and bioavailable phosphorous, water content, topography and electrical conductivity of saturated paste extract (EC).The analysis of the impact was done at two pens with different time of confinement of the animals (Pen1 and Pen 2, with 16months and 7years of animal occupation, respectively). The initial exploration phase was done by electrical resistivity tomography (ERT) and electromagnetic induction (EMI) surveys were subsequently performed at a subarea for studying the spatial distribution of ECb. A grid of soil sampling up to 1m depth was done at the same subarea of the EMI survey. A geostatistical interpolation of data was performed in order to map ECb, water content, nitrogen, bioavailable phosphorous and EC.Anomalies of higher conductivity (between 6 and 10 times the background values) were found near the feedbunk and the water trough, being greater on soils with larger period of manure recharge. Water content, nitrogen of nitrates (N-NO3−), bioavailable phosphorous (Pavail.) and EC showed patterns of spatial distribution similar to ECb. These patterns are mainly associated with the runoff movement of water to the lower zones in the case of a steeper slope and the soil compaction as in the Pen 1. In the Pen 2, the patterns of spatial variability are similar for ECb and water content while anomalies of high ECb were found along an abandoned feedbunk. High values of N-NO3−, Pavail. and EC were found at this site. A longer period of manure recharge resulted in higher values of nitrogen and bioavailable phosphorous in soils.It may be stated that bulk electrical conductivity was a good spatial indicator of water, nitrogen and bioavailable phosphorous in sandy loamy soils in these pens for the investigation depth of 1m. The bulk conductivity seems to be primarily associated with water content which is the path of transport of ions through the porous medium. In all the cases, the major contents of nitrogen and bioavailable phosphorous in the soil were associated with high bulk electrical conductivity when water content was above an equivalent depth of water of 100mm. The soil moisture status should be taken into account before an electromagnetic exploration for detecting soil contamination. Regarding the impact on groundwater pollution, the proximity of the water table to the surface seems to be more influential than the animal stocking rate for a longer period.

Influence of the basic state zonal flow on convectively coupled equatorial waves

AbstractObservational data are used to test the hypothesis that the basic state modulates the dispersion properties of convectively coupled equatorial waves (CCEWs). This hypothesis is based on shallow water theory, which predicts that the zonal speed of propagation of such tropospheric equatorial modes is altered by the equivalent depth and the basic zonal flow. Localized space‐time spectra are calculated to investigate how CCEW spectral peaks vary across the tropics and how they are affected by the variations in zonal wind observed geographically and by season. Doppler shifting by the basic state barotropic zonal flow is readily identified. Once this Doppler shifting is taken into account, the equivalent depths of CCEWs inferred from global power spectra are surprisingly uniform, both geographically and temporally. However, there are also detectable modulations that appear consistent with changes in vertical shear of the zonal flow, along with other shifts that are not as easily explained.

A new two-staged model to predict corrosion degree of steel bars in cracked concrete area

In order to quantitatively describe the local corrosion process of steel bars in cracked concrete area, a new two-staged utility model is established, and the effect of transverse cracks on the reinforcement corrosion is analyzed from the angle of long-term service performance evaluation for reinforced concrete structure. Moreover, based on the principle of spectral analysis for environmental action of concrete, an equivalent relationship is established between the corrosion rate in the natural environment and that under the standard temperature and relative humidity condition according to the principle of equivalent annual corrosion depth. Comparison between the inspection results from some references and the calculated values by the two-staged utility model validates the feasibility of the proposed model. The model was applied to Chinese Railway Track System (CRTS)II ballastless track slab with transverse dummy joints, from which satisfactory results of corrosion degree of steel bars were obtained.

Discussion of “Skimming, Nonaerated Flow on Stepped Spillways over Roller Compacted Concrete Dams” by Inês Meireles, Floriana Renna, Jorge Matos, and Fabián Bombardelli

The nonaerated region may occupy a large portion of the skimming flow in steep, stepped spillways, particularly for relatively high unit flow rates. In spite of the numerous contributions on the hydraulic properties at both the inception point of air entrainment and the aerated region, much less is known regarding the flow in the nonaerated region. In this paper, new empirical evidence, based on an extensive data set obtained during several years in a large-scale facility, sheds light on the features of the nonaerated-flow region. Diverse ways to locate and estimate the main hydraulic properties at the inception point are first discussed and compared. Then, expressions capable of characterizing the main flow variables along the nonaerated region are presented, namely, the boundary-layer development, the velocity distribution, the equivalent clear-water depth, the characteristic depth taking into account the free-surface unsteadiness due to turbulence, and the energy dissipation. The energy dissipation is observed to be larger than that for smooth spillways, although much smaller than values typically reported for aerated flows at the toe of stepped spillways.

실대형 실험을 이용한 가진주파수 변화에 따른 콘크리트궤도의 동적평가

호남고속철도에 부설된 동일한 궤도노반시스템을 실제 열차하중이 가능한 실대형 가진시험을 통해 성능을 평가하였다. 실험결 과 Odemark 등가깊이 이론에 의한 노반압력과 매우 유사한 것을 확인하였다. 콘크리트궤도에서 정적하중 330 kN을 재하시 노반 상부의 토압은 50 kPa 이내로 발생하였고, 정적하중시험과 반복하중시험 결과는 비교적 큰 차이가 없었다. HSB의 탄성변위는 증속시험 시 관리기준값 1 mm에 비해 약 1/100 수준이며, 노반의 탄성변위량과 비교해볼 때 1/175 정도로 매우 작은 변위가 발생하였다. 가진주파수의 크기에 따라 궤도노반의 동적거동은 가진주파수가 35 Hz이하에서는 모든 측정값이 거의 선형적으로 증가하였으나, 35 Hz이상에서는 윤중, 변위, 지반가속도 등이 감소하였다. In this study, the full scale model tests were performed with track-roadbed system such as Ho-nam high speed railway. The measured data gives good similar a roadbed pressure with equivalent depth to the Odemark's theory. In the case of earth pressures have a under 50 kPa at upper-subgrade applying 330 kN static loading. Results of cyclic loading tests did not differ significantly from those of static loading test. The elastic displacement at HSB layer has a level of 1/100 compared to the 1 mm that it was evaluation criteria for speed up of High Speed Railway. Elastic displacement at subgrade layer was measured a level of 1/175. The dynamic characteristics of track-roadbed with loading frequency level were linearly increased under 35 Hz, while the wheel loading, displacement and acceleration of roadbed were decreased loading frequency above 35 Hz.

Molecular kinetic theory of boundary slip on textured surfaces by molecular dynamics simulations

A theoretical model extended from the Frenkel-Eyring molecular kinetic theory (MKT) was applied to describe the boundary slip on textured surfaces. The concept of the equivalent depth of potential well was adopted to characterize the solid-liquid interactions on the textured surfaces. The slip behaviors on both chemically and topographically textured surfaces were investigated using molecular dynamics (MD) simulations. The extended MKT slip model is validated by our MD simulations under various situations, by constructing different complex surfaces and varying the surface wettability as well as the shear stress exerted on the liquid. This slip model can provide more comprehensive understanding of the liquid flow on atomic scale by considering the influence of the solid-liquid interactions and the applied shear stress on the nano-flow. Moreover, the slip velocity shear-rate dependence can be predicted using this slip model, since the nonlinear increase of the slip velocity under high shear stress can be approximated by a hyperbolic sine function.

Closure to “Skimming, Nonaerated Flow on Stepped Spillways over Roller Compacted Concrete Dams” by Inês Meireles, Floriana Renna, Jorge Matos, and Fabián Bombardelli

The nonaerated region may occupy a large portion of the skimming flow in steep, stepped spillways, particularly for relatively high unit flow rates. In spite of the numerous contributions on the hydraulic properties at both the inception point of air entrainment and the aerated region, much less is known regarding the flow in the nonaerated region. In this paper, new empirical evidence, based on an extensive data set obtained during several years in a large-scale facility, sheds light on the features of the nonaerated-flow region. Diverse ways to locate and estimate the main hydraulic properties at the inception point are first discussed and compared. Then, expressions capable of characterizing the main flow variables along the nonaerated region are presented, namely, the boundary-layer development, the velocity distribution, the equivalent clear-water depth, the characteristic depth taking into account the free-surface unsteadiness due to turbulence, and the energy dissipation. The energy dissipation is observed to be larger than that for smooth spillways, although much smaller than values typically reported for aerated flows at the toe of stepped spillways.

Study on the Borehole Stability in Liulin Coal Reservoirs

This paper studied the borehole stability in Liulin bituminous core reservoirs during under-balanced drilling. The equivalent depth method was applied to study the formation pore pressure. The floor drain test method was applied to study the ground stress. Core strength experiments combined with logging data were used in the establishment of core strength predicting model. Mechanics analysis model was founded to study the borehole stability in the core reservoir. According to the studying and analyzing results, the under-balance drilling in Liulin coal reservoirs enjoys good borehole stability.

Japan Aerospace Exploration Agency GCOM-W1 satellite snow depth product: outcome of the first winter

Snow observations from space play an important role in hydrological and climatological studies. They are especially important in remote areas with low (or none) population and sparse conventional observations at the ground. At the mid latitudes, they are needed especially for assimilation of spatially distributed data concerning snow water equivalent or snow depth derived from microwave satellite data to snowmelt models. This paper presents discussion on several problems with satellite derived snow observations focusing on the JAXA GCOM-W1 snow depth product. This product was analyzed for the period of October 1, 2012, to April 30, 2013, for an area of Poland and verified against ground observations. Benefits and disadvantages of these products were discussed in comparison to other satellite microwave products concerning snow properties. Problems with proper validation against “ground truth” were also highlighted. The possible alternative use of AMSR2 microwave data was also presented.