Vertical Depth Research Articles

Smoothed Particle Hydrodynamics Simulation of the Dynamic Water Pressure inside an Arch Rib of an Arch Bridge Subjected to Seismic Excitation

The dynamic pressure exerted on an arch rib by inner water under seismic excitation was studied based on the smoothed particle hydrodynamics (SPH) numerical model. Numerical cases of different seismic excitations in both the horizontal and vertical directions and different water depths were carried out. The fast Fourier transform (FFT) of dynamic pressure exerted on the arch rib showed that the spike frequency is related to the water depth. The surface wave frequency of inner water is very close to the first spike frequency. The first spike frequency comes close to the second and fourth vibration frequencies when the inner water reaches the depth of 18 m and 11.3 m, respectively. This will likely lead to the resonance of the entire arch rib. By considering barely the first spike frequency, when designing a new arch bridge, the possibilities of resonance in its second and fourth modes under seismic excitation cannot be ruled out. Based on the findings of this investigation, the inner water effect should be considered during the arch bridge design stage.

Contamination vertical distribution and key factors identification of metal(loid)s in site soil from an abandoned Pb/Zn smelter using machine learning

Soil heterogeneity makes the vertical distribution of metal(loid)s in site soil vary considerably and poses a challenge for identifying the key factors of metal(loid)s migration in site soil profiles. In this study, a machine learning (ML) model was developed to study a typical abandoned Pb/Zn smelter using 267 site soils from 46 drilling points. Results showed that a well-trained ML model could be used to identify the key factors in determining the contamination vertical distribution and predict the metal(loid)s contents in subsurface soil. As, Cd, Pb, and Zn were the primary pollutants and their vertical migration depth arrived to 4–6 m. Based on the predictive performance of different ML algorithms, the extreme gradient boosting (XGB) was selected as the best model to produce accurate predictions for the most metal(loid)s content. Contents of As, Cd, Pb, and Zn in the heavily contaminated zones declined with an increase of soil depth. The metal(loid) contents in surface soil of 0–2 m could be readily used to predict the content of Cd, Cr, Hg, and Zn in subsurface soil from 2 m to 10 m. Based on the metal-specific XGB models, sulfur content, functional area, and soil texture were identified as key factors affecting the vertical distribution of As, Cd, Pb, and Zn in site soil. Results suggested the ML method is helpful to manage the potential environmental risks of metal(loid)s in Pb/Zn smelting site.

A reduced-scale experimental investigation of facade flame behavior ejected from a top-hung window of fire compartment

In case of a room fire, facade flame ejected from a window could lead to catastrophic consequence. Top-hung window is a common feature in modern buildings. This paper investigates, for the first time, the ejected facade flame behavior from a top-hung window. Experiments are performed by a cubic scale model compartment with a top-hung window of four opening angles and four dimensions under various heat release rates (HRR). A total of 119 test conditions are involved to quantify generally the ejected facade flame behavior and morphological characteristics, characterized by its vertical height and horizontal depth (normal to facade). It is found that the position of neutral plane between the inflow and outflow at the top-hung window increases with opening angle, while being smaller as the window width is larger or the window height is smaller. The critical HRR for flame ejection is higher as the top-hung window opening angle is larger. The facade flame depth increases, while the flame height decreases, with increasing of opening angle of the top-hung window. A new characteristic length taking into account both the top-hung window dimensions and window opening angle is deduced by the mass balance analysis of the inflow and outflow as well as ventilation factor through the top-hung window. New dimensionless models are established to describe the critical HRR for flame ejection, the height of the facade flame and flame depth as a function of the newly derived top-hung window ventilation factor as well as characteristic length, showing good fitting of experimental results. The present study provides the basic data, understanding and model of facade flame characteristics from a top-hung window of a fire compartment, which is essential in estimation of its risk and adverse impact to urban environment as a new supplementary over previous knowledge limited for freely opened windows.

Collaboration Allows Introduction of Automated Advisory System in Offshore Well

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31443, “Operator and Service Provider Collaborate To Successfully Introduce an Automated Advisory System in a Wildcat Exploration Well Offshore Mexico,” by Peter Batruny, SPE, M. Razali Paimin, and M. Arriffuddin Allauddin, Petronas, et al. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission. _ The authors of the complete paper describe a collaboration between an operator and a service company formed during a project’s well-planning phase to evaluate the feasibility of automation for a holistic drilling-advisory platform that facilitates real-time decision making based on downhole and surface data. The collaboration resulted in a successful deployment of an automation platform as a solution to manage and mitigate risks and optimize drilling operations in exploration wells. Introduction The probability of nonproductive time (NPT) and invisible lost time (ILT) occurring in exploration wells is higher because of a lack of experience in the area concerned. The operator estimates that NPT caused by hole problems accounts for 22% of total NPT (Fig. 1). The authors’ work aims to apply a novel, automated drilling-operation monitoring technique on a wildcat exploration well in the Gulf of Mexico through the collaboration of operator and service provider. A collaborative framework and technology integration is applied to minimize the effect of uncertainty on NPT and ILT. Description and Application of Equipment and Processes The well is in the Salina Basin, approximately 67 nautical miles north of shore, with an estimated water depth of 66 m below mean sea level. The maximum planned well total depth was approximately 4400 m true vertical depth subsea. The proposed well lies in a four-way anticline structure. Despite the abundance of wells around the location, most exploration activities performed in the area have been focused on the Middle and Lower Pliocene (shallower) interval, causing well correlation at the Miocene stratigraphic interval to be extremely limited. In addition, the disparate thicknesses of the Pliocene sediments in the area create significant challenges in terms of geological correlation. Five offset wells were used as stratigraphy correlation, with distances ranging from 8 to 31 km. Downhole losses and borehole instability were experienced in all offset wells, with well-control events experienced in three out of five offset wells.

E&P Notes (October 2022)

E&P Notes (October 2022)

Approach Uses Intentional Deadheading of ESPs To Improve Run Life

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204521, “Intentionally Deadheading SAGD ESPs: An Unconventional Approach To Improve Run Life,” by J. Daine Studer, Jesus E. Chacin, SPE, and Roger Walters, SPE, ConocoPhillips, et al. The paper has not been peer reviewed. _ Electrical submersible pumps (ESPs) used in steam-assisted gravity-drainage (SAGD) applications run at the highest motor temperatures possible. However, they cool very rapidly when shut down. High cooling rates promote motor oil volumetric contraction, eventually leading to wellbore fluid ingress and short-circuited motors. The complete paper discusses successful field tests designed to decrease ESP cooling rates by inducing controlled deadheads rather than shutting down ESPs. Various extended-deadhead field trials (of up to 70 or more days in duration) validated the approach while confirming that no deadhead-related ESP damage was induced. Introduction In conventional operations, when ESPs operate in deadhead mode (i.e., no flow into the production line), all useful lifting work turns into heat and the ESP can overheat rapidly. The tendency to overheat increases as the gas/oil ratio of the lifted fluid increases. This type of overheating failure usually manifests as burnt stage components and cable burns close to the pump. At the Surmont SAGD plant, however, anecdotal evidence when ESPs inadvertently ran for a few hours in deadhead mode showed that SAGD ESPs cooled during deadhead events. This was the genesis of the project presented in the paper, which is to intentionally deadhead, rather than shut down, SAGD ESPs to offset or partially offset naturally occurring rapid cooling. Application Background A typical Surmont ESP producer completion features wells that are surface-cased with 13⅜-in. casing to approximately 120 m, and 9⅝-in. to approximately 350–450 m true vertical depth. Horizontal sections range from 600 to 800 m in length and are terminated with 7-in. slotted liners or flow-control-device strings. ESPs produce through 3½-in. tubing and are set at an inclination angle of 75° to 82° in specially drilled tangent sections. A 21/16-in. guide string is used to protect and land as deep as possible an optical fiber string inside a protective coiled string (1¼ in.). This optical fiber is used to obtain distributed temperature measurements. A bubble tube is bundled inside the ESP power cable to provide single-point downhole pressure measurements at pump-setting depth (PSD) in the annular space. Most ESPs used at Surmont feature power ranging from 60 to 180 hp to lift total gross production rates to the 1,000–6,500 B/D range. Water cuts average from 70 to 73%. The most-common failure modes experienced at Surmont caused by temperature cycling include worn mechanical shaft seals, metal bellows overextension, and thrust bearing wear (Fig. 1).

A method for a fast and economical in situ collection of pore water in sandy sediments

Marine sediment represents one of the most significant carbon reservoirs. Extraction of pore water from the uppermost 10 cm of the sediment column, just below the sediment-water interface, in coastal environments can be used to assess the rapid chemical changes caused by extensive subsurface biological and chemical reactions. However, owing to relatively large grain size of the sediment in some shallow coastal environments, sediment and pore water mixes quickly making collection of core samples for pore water extraction extremely difficult. Here, we present a simple method utilizing Rhizons to collect in situ pore water from coastal environments. We conducted both ex situ and in situ experiments, using fluorescein as a tracer, to understand the influence of overlying water during pore water collection through this method. These experiments also allowed us to assess the volume of pore water collected before fluorescein is observed in the samples at different vertical depths within the sediment column. We found that: 1. discarding the initial 2 mL of water minimizes the memory effect, 2. collection of 10 mL of water avoids interference from surrounding pore water and the overlying water column and 3. a vertical resolution of minimum 2 cm could be attained for sediments with grain size of 1 mm and less. We finally present data from two linear transects from different sites in the Gulf of Aqaba. Results from these case studies demonstrate expected patterns of high concentrations of iron and hydrogen sulfide in pore water from the sediment where surface coloration suggested iron and sulfate reduction was dominating, respectively. Both case studies, therefore, independently validated the Rhizon sampler method for collecting pore water in situ from marine sediments in coastal environments.

High-resolution vertical biogeochemical profiles in the hyporheic zone reveal insights into microbial methane cycling

Abstract. Facing the challenges of climate change, policy making relies on sound greenhouse gas (GHG) budgets. Rivers and streams emit large quantities of the potent GHG methane (CH4), but their global impact on atmospheric CH4 concentrations is highly uncertain. In situ data from the hyporheic zone (HZ), where most CH4 is produced and some of it can be oxidized to CO2, are lacking for an accurate description of CH4 production and consumption in streams. To address this, we recorded high-resolution depth-resolved geochemical profiles at five different locations in the stream bed of the river Moosach, southern Germany. Specifically, we measured pore-water concentrations and stable carbon isotopes (δ13C) of dissolved CH4 as well as relevant electron acceptors for oxidation with a 1 cm vertical depth resolution. Findings were interpreted with the help of a numerical model, and 16S rRNA gene analyses added information on the microbial community at one of the locations. Our data confirm with pore-water CH4 concentrations of up to 1000 µmol L−1 that large quantities of CH4 are produced in the HZ. Stable isotope measurements of CH4 suggest that hydrogenotrophic methanogenesis represents a dominant pathway for CH4 production in the HZ of the river Moosach, while a relatively high abundance of a novel group of methanogenic archaea, the Candidatus “Methanomethyliales” (phylum Candidatus “Verstraetearchaeota”), indicate that CH4 production through H2-dependent methylotrophic methanogenesis might also be an important CH4 source. Combined isotopic and modeling results clearly implied CH4 oxidation processes at one of the sampled locations, but due to the steep chemical gradients and the close proximity of the oxygen and nitrate reduction zones, no single electron acceptor for this process could be identified. Nevertheless, the numerical modeling results showed potential not only for aerobic CH4 oxidation but also for anaerobic oxidation of CH4 coupled to denitrification. In addition, the nitrate–methane transition zone was characterized by an increased relative abundance of microbial groups (Crenothrix, NC10) known to mediate nitrate and nitrite-dependent methane oxidation in the hyporheic zone. This study demonstrates substantial CH4 production in hyporheic sediments, a potential for aerobic and anaerobic CH4 oxidation, and underlines the high spatiotemporal variability in this habitat.

Regenerative potential of biphasic calcium phosphate and enamel matrix derivatives in the treatment of isolated interproximal intrabony defects: a randomized controlled trial.

BackgroundThe combined use of biomaterials for regeneration may have great biological relevance. This study aimed to compare the regenerative potential of biphasic calcium phosphate (BCP) alone and with growth factor enamel matrix derivatives (EMDs) for the regeneration of intrabony defects at 1 year.MethodsThis randomized controlled trial included 40 sites in 29 patients with stage II/III periodontitis and 2/3 wall intrabony defects that were treated with BCP alone (control group) or a combination of BCP and EMD (test group). BCP alloplastic bone grafts provide better bio-absorbability and accelerate bone formation. EMDs are commercially available amelogenins. Mean values and standard deviations were calculated for the following parameters: plaque index (PI), papillary bleeding index (PBI), vertical probing pocket depth (V-PPD), vertical clinical attachment level (V-CAL), and radiographic defect depth (RDD). Student paired and unpaired t-tests were used to compare the data from baseline to 12 months for each group and between the groups, respectively. The results were considered statistically significant at p<0.05.ResultsAt 12 months, the PI and PBI scores of the control and test groups were not significantly different (p>0.05). The mean V-PPD difference, V-CAL gain, and RDD difference were statistically significant in both groups at 12 months (p<0.001 for all parameters). Intergroup comparisons showed that the mean V-PPD reduction (2.13±1.35 mm), V-CAL gain (2.53±1.2 mm), and RDD fill (1.33±1.0 mm) were statistically significant between the groups at 12 months (p<0.001 for all parameters).ConclusionBCP and EMDs combination is a promising modality for the regeneration of intrabony defects.

Probabilistic Approach Guides Field Development Plan in Niger Delta

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207146, “Conceptual Field Development Plan for X Field,” by Khadijah Ibrahim, SPE, Petrus Nzerem, and Ayuba Salihu, SPE, Nile University of Nigeria, et al. The paper has not been peer reviewed. _ The development plan of a new oil field discovered in a remote offshore environment in the Niger Delta was evaluated. Because the oil in place was uncertain, a probabilistic approach was used to estimate the stock-tank oil originally in place (STOOIP) using low, base, and high cases. The base model is recommended for further implementation. The quantity of oil produced is estimated at 15,000 STB/D, which will require a separator that has the capacity of holding a liquid rate of approximately 20,000 STB/D. The authors find that this developmental plan is cost-effective. Introduction Field X is offshore Nigeria in water depths of 330 ft. The field has an uncertain oil in place, with a possibility of low, base, and high cases. The field reservoir information is available from the exploration and seismic well data provided. The field size (i.e., STOOIP) is estimated at 95 million (low), 145 million (base), and 300 million (high) STB, with an irreducible water saturation of 22%. The reservoir depth is 7,400 ft true vertical depth subsea (TVDSS), with a net pay thickness of 45 ft. The aquifer supporting the reservoir has a strength of 9, with a permeability of 200 md and a porosity of 18%. Generally, the reservoir has permeability and compressibility of the rock formation obtained from the log results of 250 md and 3.5×10–6 psi–1. The reservoir pressure is measured to be 3,400 psia. The field development plan will incorporate production forecasts from the target date of first production, 1 January 2023, through 1 January 2038, for a 15-year field life. The complete paper presents the field development strategies and economic analysis of different well models to evaluate the most-efficient modeling profile for the new field. Methodology Well-Modeling Profile and Performance Analysis. It is assumed that the field will be produced using a platform with a wellhead reference depth of 20 ft above the rotary kelly bushing. The well is assumed to be a vertical well with no deviation. The skin value is estimated to be 1, thereby having a slight effect on the productivity index. Pressure/volume/temperature (PVT) data were available for the oil in place. Using commercial software, the fluid parameters for bubblepoint pressure, oil volume factor, and oil viscosity were matched in the PVT analysis at a reservoir temperature of 170°F and a pressure of 3,400 psia. The measurements of formation volume factor, gas/oil ratio, and oil viscosity at this pressure were used to provide a single match point for the generation of PVT data.

Estimating mistletoe biomass in a semi-arid savanna woodland, southwest Zimbabwe

Despite the biological importance of mistletoes in forests and woodlands globally, mistletoe biomass is rarely quantified, particularly in tropical regions. Thus, we constructed allometric models to predict the biomass of three mistletoe species (Erianthemum ngamicum, Plicosepalus kalachariensis, and Viscum verrucosum) in semi-arid savanna, southwest Zimbabwe. We destructively sampled 30 individuals of each mistletoe species and recorded their broad haustorium diameter, narrow haustorium diameter, and the width, breadth, vertical depth, and percentage of leaves of the whole plant. After measuring the dry biomass of each mistletoe, we fitted linear regression models – selected and compared based on corrected Akaike Information Criterion (AICc) minimization. Mistletoe volume (r2 = 0.95) best predicted biomass in E. ngamicum, while mistletoe size was the best predictor for P. kalachariensis (r2 = 0.90) and V. verrucosum (r2 = 0.95). Models using haustorium diameter had the lowest predictive power in all species. V. verrucosum and P. kalachariensis had greater total mean dry biomass than E. ngamicum. Stems constituted the larger proportion of total biomass than leaves in E. ngamicum (75 vs. 23%) but the reverse is true for P. kalachariensis (40 vs. 58%). Of the total biomass, fruits and flowers constituted 6% in V. verrucosum and E. ngamicum and 2% in P. kalachariensis. The leaf to stem biomass contribution decreases in E. ngamicum but increases in P. kalachariensis as the plant grows. Models using mistletoe biometry (width, breadth, and vertical depth of the whole plant), rather than host size (height, diameter at breast height, and canopy area), best predicted total mistletoe biomass. Not only does this enable estimation of mistletoe biomass beyond the scale of infected individuals, but the contribution of mistletoes to local biomass, carbon stock, and ecosystem processes (e.g., nutrient cycling) can also be quantified at different spatial scales helping elucidate their keystone role in semi-arid savanna.

Trench topography in subduction zones: A reflection of the plate decoupling depth

Subduction of lithospheric plates produces narrow, linear troughs (trench) in front of the overriding plates at the convergent boundaries. The trenches show a wide variation in their topographic characteristics, such as width, vertical depth, and bounding surface slopes. Benchmarking their controlling factors is thus a crucial step in the analysis of trench morphology. This article identifies the mechanical coupling between the subducting and overriding plates as a leading factor in modulating the topographic evolution of a trench. The maximum depth of decoupling (MDD) is used to express the degree of decoupling at the plate interface. We simulate subduction zones in computational fluid dynamic (CFD) models to show the topographic elements (maximum negative relative relief: D; fore- and hinter-wall slopes: θF and θH; opening width: W) of trenches as a function of the MDD within a range of 30–120 km. Both D and θ strongly depend on the MDD, whereas W is found to be relatively less sensitive to the MDD, implying that the narrow/broad width of a trench can change little with the plate decoupling factor. We also show that the MDD critically controls the fore-arc stress fields of a trench, switching a compressive to tensile stress transition with increasing MDD. This study finally validates the model findings with well-constrained natural trench topography.

Experimental Investigation on Flow Behavior of Paste Slurry Transported by Gravity in Vertical Pipes

In order to dispose of large quantities of mineral tailings, paste backfill is proposed and widely adopted. Paste backfill, which has high concentration and yield stress and behaves as a non-Newtonian fluid, is prepared at the surface plant and then transported underground. Vertical pipelines are more likely to suffer various failures, such as pipe breaks, wear and plugging, during the transport process. Few present studies focus on the flow behavior of paste slurry flowing in vertical pipes. In this work, two L-shaped pipeline systems with internal diameters (ID) of 40 mm and 65 mm with electrical resistance tomography (ERT) were manufactured to visualize flow regimes and measure the axial velocity and pipe pressure of slurry flowing in the upper and lower zones of vertical pipes. Flow regimes were extracted from ERT-reconstructed images stacked by time-series. Based on this, four typical flow regimes were summarized, and the characteristics of velocity and pressure change with vertical pipe depth were discussed.

Stability assessment of long gateroad pillar in ultra-thick coal seam: an extensive field and numerical study

Sustainability of an underground longwall operation is highly dependent on stability of the pillars during the panels extractions to ensure the continuous serviceability of gateroads. In Chinese underground longwall mining, the gateroads are typically driven as a single roadway with a “long gateroad pillar” which is different to a common practice where a gateroad consists of a number of pillars known as chain pillars. Such a unique practice has been proven to be more economical with maximum recovery while the safety remains at its highest level. In this study, based on the data obtained from Tongxin coal mine in China, the mechanical stability of the driven long gateroad pillar was investigated. The focus was on two nearby longwall top coal caving panels and their impacts on the mechanical behaviour of long gateroad pillar during the longwall retreat. To do so, initially an area of the gateroad was selected for the field instrumentation and data collection. These included vertical stress measurement and depth of damage assessment within the gateroad pillar and the longwall panel. Hence, the convergence level of gateroad was quantified to be used for the numerical modelling and assessing the performance of the designed long gateroad pillar based on the finite difference modelling technique using FLAC3D. Double-yield and strain-softening ubiquitous-joint constitutive models were used to simulate goaf material and strata, respectively. Finally, an extensive sensitivity analysis was conducted to compare the mechanical behaviour of a range of wide and narrow long gateroad pillars. It was concluded that the 50 m wide pillar is an ideal dimension for the future panels of Tongxin coal mine to achieve the maximum productivity and safety.Article highlightsThe validated numerical model was used to study on stability of “long gateroad pillar”.Premature yielding of the 38 m pillar would lead to severe geotechnical issues.Deep roof blasting of goaf edge or 50 m pillar can improve pillar conditions

Study on Sustainable Well Water Pumping Technology to Melt Ice in Winter for the Middle Route of the South-to-North Water Diversion Project

In order to improve the water delivery capacity of the middle route of the South-to-North Water Diversion Project in winter, the technology of pumping well water to melt ice was previously adopted to improve the water temperature of the channel. In order to protect the local ecology and channel water quality during the process of pumping and recharging, this paper has analyzed the optimal limit to the range of groundwater level fluctuations and groundwater temperature fluctuations. The Baiquan Underground Reservoir was considered as the research object, and a three-dimensional numerical model of hydrothermal coupling was established. Correlation analyses of pumping and recharge capacity with various factors, and between temperature changes after recharging and various factors, were carried out with a view to protecting local water quality. The single well pumping and recharging scheme was optimized by genetic algorithm. The quantitative estimation formula of pumping and recharge water capacity, and the well depth, permeability coefficient, initial water level, and duration of continuous pumping and recharge, as well as the recovery water level variation formula, were established under the limitation of water level fluctuation. The quantitative relationship between horizontal maximum diameter, L, and the recharge flow rate, the continuous recharge duration, vertical maximum depth, H; and the well depth, temperature change rate, K, and the recharge water temperature, were obtained. The results showed that the permeability coefficient and soil thermal conductivity had little effect on the temperature field change. Additionally, recharge should be carried out in summer, when the temperature of recharge water is above 14.8 °C. When the number of pumping or recharging times, n, is two, the total amount of pumping or recharging during the operation period reaches its maximum. Compared with continuous operation during the operating period, this report found that the total amount of pumped water would increase by 1.1 × 106 m3, and the total amount of recharge would increase by 7 × 105 m3.

Self-potential time series reveal emergent behavior in soil organic matter dynamics

The active cycling of carbon between soil organic matter and the atmosphere is of critical importance to global climate change. An extensive body of research exists documenting the capricious nature of soil organic matter (SOM) dynamics, which is symptomatic of an intricate network of interactions between diverse groups of heterotrophic microorganisms, complex organic substrates, and highly variable local environmental conditions. These attributes are consistent with elements of complex system theory and the temporal evolution of otherwise unpredictable patterns of behavior that emerge from long range dependency on initial conditions. Here we show that vertical depth profile of self-potential (SP) time series measurements responds in a quantitative manner to variations in soil moisture, SOM concentrations, and relative rates of microbial activity. Application of detrended fluctuation analysis (DFA) of self potential time series data is shown additionally to reveal the presence of long-range dependence and emergence of anomalous electrochemical diffusion behavior, both of which diminish with depth as SOM specific energy densities decline.

Drip fertigation and plant hedgerows significantly reduce nitrogen and phosphorus losses and maintain high fruit yields in intensive orchards

A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin. Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices. The four experimental treatments were conventional fertilization (CK), drip fertigation (DF), conventional fertilization combined with plant hedgerows (C+H), and drip fertigation combined with plant hedgerows (D+H). The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge. Surface runoff discharge under the treatments without plant hedgerows totaled 15.86% of precipitation, while surface runoff discharge under the treatments with plant hedgerows totaled 12.82% of precipitation. Plant hedgerows reduced the number of runoff events and the amount of surface runoff. Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff, and fertilization is an important factor affecting the losses of nitrogen and phosphorus. In CK, approximately 7.36% of nitrogen and 2.63% of phosphorus from fertilization entered the surface water through runoff. Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen (TN) and total phosphorus (TP). Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%, respectively, in comparison to the CK totals. Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil, which increased the pear yield. The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.

Well Log Lithological Analysis and Petrophysical Parameters Calculation of Miocene to Recent Formation Reservoirs in Well P10, Offshore, Northern Rio Del Rey Basin (Southwest Cameroon, Gulf of Guinea)

The P10 well is located offshore, in the Northern part of the Rio Del Rey basin in southwest Cameroon. Although the Rio Del Rey basin is the most prolific coastal basin in Cameroon given the production results from several fields in the southern part, yet it remains very little explored in its northern part. This work evaluation the petroleum potential in the northern part of the Basin using a combination of the &amp;quot;Quick Look&amp;quot; interpretation of the logs recorded in well P10 and &amp;quot;complex matrix&amp;quot; facies analysis of the different lithofacies through the neutron porosity - bulk density (NPHI-RHOB) and delta time sonic - bulk density (DT-RHOB) diagrams. The composite log includes the Gamma Ray log; Caliper log; Deep Resistivity log; neutron porosity log and bulk density log. In addition to this composite log, a geological end of well report is completed to refine the results. Ten (10) near sand/sandstone reservoirs were delineated between 950 and 1803 TVD m (true vertical depth in meter) with very good porosities (12% &amp;lt;&amp;Phi;&amp;lt; 30%) as well as a mineralogical composition dominated by quartz. Clay volumes are relatively lower than 18% except in reservoirs R5 and R6 where they are around 24%, giving the latter a sandy-clay lithology. Reservoirs R2 and R4 contain oil, the latter with a WOC (Water Oil Contact) at ~1172 m and a GOC (Gas Oil Contact) at 1169 m. Reservoirs R6; R7; R8; R9; R10 all contain Gas and Water with WGC (Water Gas Contact) located at ~1431 m; 1530 m; 1690 m and ~1790 m respectively. In the light of these results, there is a clear dominance of gaseous hydrocarbon reservoirs over oil-impregnated ones in the study area. The results provided by this work can serve as baseline data for future oil and gas exploration projects in the northern part of the Rio Del Ray Basin.

Equatorial Plasma Bubble Detection Using Vertical TEC From Altimetry Satellite

AbstractIn this study, we detect the equatorial plasma bubble (EPB) using vertical total electron content (vTEC) from altimetry satellite for the first time. The Jason‐2 vTEC data during the high solar activity year of 2014 are employed to investigate the characteristics of EPB. The latitudinal and temporal variations of EPB are analyzed first and the results are consistent to those of previous reported studies, suggesting the observed EPB events are reliable. Furthermore, due to the features of vTEC, the zonal scale and vertical depth of EPB are also obtained: the zonal scale varies mainly with small scope of 0.5 ∼ 1.5° and seems to be independent of latitude, whereas the vertical depth is related to latitude with large value located in the crest region of the equatorial anomaly. The results show the altimetry satellite vTEC is feasible for EPB detection and can serve as a new tool for EPB monitoring.

Retracted: “Motion Model of Free-Standing Racks Considering Two-Dimensional Gap Flow” [ASME Journal of Pressure Vessel Technology, 2022, 144(4), p. 041402; DOI: 10.1115/1.4052567

Abstract The spent fuel pool of a nuclear power plant is a huge water tank with a vertical and horizontal depth of more than a dozen meters, and multiple box-shaped spent fuel racks in which spent nuclear fuel is stored are lined up in the pool. A free-standing (FS) rack is considered one of the means to improve the earthquake resistance of the spent fuel pool. The rack is not fixed to the floor so that it can move in the pool. Therefore, the inertial force due to an earthquake can be reduced by the frictional force with the floor and the fluid force from the surrounding water, and improvement in earthquake resistance can be expected. In this study, to evaluate the fluid force more precisely, the flow between the racks and the one between the racks and pool wall is treated as a two-dimensional gap flow, and the pressure loss coefficient at the flow path junction and the top of the flow path was estimated based on the steady computational fluid dynamics (CFD) calculation and incorporated into the motion model.