Deep Bed Research Articles

COMPARISON OF THE SUSPENSION STABILIZED BY POLYMER TREATMENT EFFICIENCY FOR INJECTION WELLS OF VARIOUS COMPLETIONS

The paper is devoted to the comparison of the stabilized suspension by polymer treatment efficiency of injection wells of various completions. Due to the widespread application of oil reservoirs waterflooding technology, the water and conformance control becomes an urgent objective. Control of production water cut is achieved with the help of the diversion of the injectivity profile of injection wells. The injection of special compositions allows to divert flows in the production interval, which leads to a temporary decrease in the water content of the surrounding producing wells. Completion well determines the geometry of the flow near the well or the flow mode. The purpose of the research is to analyze the results of the flow diversion in a layered heterogeneous formation near a cylindrical borehole and a flat fracture for the example treatment technology of the stabilized suspension by polymer. To solve the problem, a system of equations of “deep bed migration model” was used, describing the behavior of suspended particles in the flow and particles trapped on the rock matrix. An analytical solution of the problem of radial flow during suspension injection into a vertical injection well is obtained. A comparison of the stabilized suspension by polymer treatment on a vertical injection well is carried out for linear flow near a fracture and radial flow near vertical well. It has been found that in the radial flow, suspension particles penetrate a porous medium much worse than with linear flow. Specific characteristics are introduced and compared providing the effectiveness of conformance control by alignment of the injectivity profile of injection wells. It is shown that the treatment by stabilized suspension by the polymer of wells with fractures is more effective than the treatment of vertical wells without fractures. It was found that when treatment of vertical wells with small volumes of suspension injection, the formation of suspension cake at the inlet to highly permeable interlayers are observed. For linear flows near fractures, this effect is manifested at significantly large volumes of suspension injection.

CFD Simulation of Airflow Distribution in a Heat Pump-Assisted Deep-Bed Paddy Dryer

HighlightsUneven drying is an inevitable drawback when using heat pump-based deep-bed dryers in commercial drying industries.Understanding the drying behavior of the heat pump-based deep-bed dryers is important to optimize the drying technology.COMSOL Multiphysics is a very helpful tool as it can be used to predict the drying behavior.Abstract. Heat pump dryers are widely used in drying agricultural products because of its capability in drying products at comparatively lower temperatures in commercial scale. However, deep-bed heat pump drying (HPD) leads to uneven drying because of its poor airflow distribution in the drying chamber. Optimizing the proper design of a heat pump dryer system may reduce the non-uniformity of drying and increases dryer efficiency. This study aimed to investigate the airflow distribution in a deep bed of rough rice dried with a heat pump using Computational Fluid Dynamics (CFD). The Navier-Stokes equation, Heat transfer equation, and Fick’s Law were used in the mathematical models for simulation of air velocity, temperature, and relative humidity respectively. COMSOL Multiphysics simulation program v5.4 solved all the models with the boundary conditions of inlet velocity, inlet temperature, and drying air moisture content. The simulation was used to predict the temperature and the humidity of drying air at three different dryer locations during the drying process. Finally, the simulated data were verified using experimental results. The values of relative error and mean relative deviation for drying air temperature in paddy bed were less than ±18.05%, 13.52%. Relative error and mean relative error for air moisture in paddy bed were less than ±15.83% and 14.44%, respectively. The results indicated that the simulation model developed could effectively use for predicting the air temperature and air relative humidity with a reasonable accuracy. Keywords: CFD simulation, COMSOL Multiphysics, Heat pump drying.

Estimating the subgrade reaction at deep braced excavation bed in dry granular soil using genetic programming (GP)

Modulus of subgrade reaction (Ks) is a simplified and approximated approach to present the soil-structure interaction. It is widely used in designing combined and raft foundations due to its simplicity. (Ks) is not a soil propriety, its value depends on many factors including soil properties, shape, dimensions and stiffness of footing and even time (for saturated cohesive soils). Many earlier formulas were developed to estimate the (Ks) value. This research is concerned in studying the effect of de-stressing and shoring rigidity of deep excavation on the (Ks) value. A parametric study was carried out using 27 FEM models with different configurations to generate a database, then a well-known “Genetic Programming” technique was applied on the database to develop a formula to correlate the (Ks) value with the deep excavation configurations. The results indicated that (Ks) value increased with increasing the diaphragm wall stiffness and decreases with increasing the excavation depth.

Co-digestion of deep bedding and wastewater from pig farming: A new strategy for bioenergy increase and biofertilizer recovery

In the present study, a pilot-scale plug flow reactor was used for anaerobic co-digestion of swine wastewater (SWW) and deep bedding (DB). The reactor was operated with organic loads between 315.6 and 782.8 kgCOD d-1 in winter and summer. The experiment was conducted in 4 phases with the addition of DB in SWW in proportions of 0, 5, 10 and 15 tons. Biogas productions 3 times higher were recorded when 15 ton of DB were applied, generating 634.5kWh d-1 of bioenergy in summer and 267kWh d-1 in winter. Application of DB in winter promoted stability in biogas production. CH4 concentrations from 60 to 68% were recorded in winter and from 61 to 72% in summer. Methane yield was maximum in summer with application of 15 ton of DB (0.343m3 KgCODRem-1). Removals of volatile solids and COD were within the ranges of 60-70 and 61-84%, respectively. There was no accumulation of volatile fatty acids (VFAs), nor pronounced decrease of pH in the reactor. The biofertilizer produced in all experimental stages can be used for agricultural cultivation with application rate defined based on the concentrations of Na and K to avoid soil salinization.

Imaging subsurface geological complexity (2D/3D) beneath the Greater Srinagar region of the Kashmir basin, Northwest Himalaya

ABSTRACTA high‐resolution microtremor measurement in Greater Srinagar city of the Kashmir valley has been analysed to image 2D and 3D subsurface geological complexities. This region is located in the highly seismogenic Himalayan belt and sits atop a deep sedimentary lake bed with a laterally varying thickness of soft sediments. Srinagar region is a major economic centre and the capital city of the Kashmir valley with 2 million inhabitants living at high seismic risk. To assess the subsurface complexity beneath the city, we present: (1) high‐resolution subsurface shear wave velocity Vs structure using the horizontal‐to‐vertical spectral ratio inversion; (2) shear wave velocity for top 30 metres of soil column (VS30) map with National Earthquake Hazards Reduction Program site classification; (3) comparison of VS30 maps calculated from horizontal‐to‐vertical spectral ratio inversion and topographic slope methods; and (4) azimuthal behaviour of horizontal‐to‐vertical spectral ratio peaks, all of which unravel the subsurface spatial heterogeneity and suitability for the building of engineering structures in the study area. In addition, a new matlab code is applied to generate 3D subsurface Vs slices in the study region in different directions using its pre‐generated 2D Vs profile data. The presented potentiality of microtremor horizontal‐to‐vertical spectral ratio technique in Srinagar region, which lies on the eastern edge of the basin with significant topographic irregularities, indicates an uneven distribution of local site effects (primary and secondary) in the case of strong ground motion. The comprehensive results can be promising in engineering analyses of local ground and structural responses in order to mitigate the impact of earthquake occurrence and seismic risk in the city and adjoining regions.

THE LONG SHELL PILE BEARING CAPACITY CALCULATION

A comparative assessment of the long steel shell-pile bearing capacity is carried out in conditions of deep bedding of dense soils on the example of the Crimean bridge. The soil column is represented by six layers of soil only the last sixth layer of which located at a depth of 62 m has a high bearing capacity. Three design schemes are considered, taking into account soil resistance along the outer side surface and under the lower end of the pile, along the outer and inner side surfaces of the pile, as well as along the outer side surface and under the lower end of the pile, taking into account the soil core and self-locking effect. The results of calculating the bearing capacity of the steel pile-shell for each of the design schemes are presented in tabular and graphical form. Conclusions are drawn about the nature of the change in the soil resistance forces with the depth of the pile immersion both along its outer and inner lateral surfaces as well as under its lower end. The depth at which the soil core formation begins as well as the depths within which the soil is compacted and self-locking inside the pile cavity has been established. In this case the pile begins to work as a pile with a closed lower end and a further increase in its bearing capacity occurs due to the frictional forces of the soil along the outer lateral surface. A comparison is made of the bearing capacity values calculated for each of the three design schemes with the partial value of the ultimate resistance according to immersion data with actual (measured) residual failures based on the results of field tests with dynamic load.

Residence time distribution and solids mixing of sawdust in a horizontal pulsed fluidized bed

A prototype horizontal pulsed fluidized bed (HPFB) has been built for continuous biomass torrefaction in our lab. Solids residence time distribution (RTD) of hemlock sawdust in the HPFB reactor was measured to study particle transport and mixing using a pulse injection of particle tracer. Effects of weir height, gas pulsation frequency, solids feed rate and gas velocity were investigated. A modified axial dispersion model was adopted to fit the experimental RTD curves, where horizontal dispersion coefficients were obtained. It is found that horizontal dispersion coefficients were slightly higher in the deeper bed. In the shallow bed, horizontal dispersion coefficients increased with increasing solids feed rate. The solids mixing intensity also found to increase with increasing the gas velocity. Horizontal solids dispersion coefficients obtained in the HPFB were significantly smaller than values calculated by literature correlations. A correlation in the shallow HPFB was established based on our experimental data. • Residence time distributions of sawdust were measured in a pulsating fluidized bed. • Horizontal dispersion coefficients D x were obtained by a dispersion model. • D x values in the pulsating fluidized beds were smaller than literature values. • A new correlation of horizontal dispersion coefficient was established.

Performance of Deep Bed Sand Filters in Nom Removal from Water under Different Operational Conditions. (Dept. E)

Performance of Deep Bed Sand Filters in Nom Removal from Water under Different Operational Conditions. (Dept. E)

Heat and moisture transfer studies on walnuts during hot air drying in a fixed-bed column dryer

• Heat and moisture transfer model was developed for fixed-bed column walnut drying. • Temperature and moisture distributions in the column and single walnuts were simulated. • Mechanisms of heat and moisture transfer during the drying process were discussed. • Good predictability achieved for drying under step-down temperature conditions. This research was conducted to better understand the mechanisms of heat and moisture transfer of walnuts during drying in a fixed-bed column dryer with heated air, and to develop a mathematical model to simulate this process. Drying experiments were performed under constant temperature and step-down temperature conditions (43, 55, 65 and 75 °C) with fixed air velocity of 0.7 m/s. The nonequilibrium transfers of liquid moisture, water vapor and heat within the single walnuts (both shell and kernel), as well as between the walnuts and drying air in the column were simulated and studied using a finite element method. The numerical results showed that the distribution of temperature and moisture content in the single walnuts played an important role in the heat and moisture transfer in the deep-bed column. The drying characteristics of walnuts were significantly affected by the non-uniformity of drying conditions surrounding the walnuts (particularly for air temperature and humidity) along the column heights. The predicted values of walnut moisture contents, temperatures, and air relative humidity at different column heights agreed well with the experimental values (R adj 2 > 0.972) under different drying conditions. This study established the theoretical basis for improving and optimizing the walnut drying process in deep-bed dryers. The developed mathematical model can be used to describe the drying characteristics and understand the mechanisms of walnuts drying in deep bed dryers.

An Invariant Protein That Colocalizes With VAR2CSA on Plasmodium falciparum-Infected Red Cells Binds to Chondroitin Sulfate A.

Plasmodium falciparum-infected red blood cells (iRBCs) bind and sequester in deep vascular beds, causing malaria-related disease and death. In pregnant women, VAR2CSA binds to chondroitin sulfate A (CSA) and mediates placental sequestration, making it the major placental malaria (PM) vaccine target. In this study, we characterize an invariant protein associated with PM called P falciparum chondroitin sulfate A ligand (PfCSA-L). Recombinant PfCSA-L binds both placental CSA and VAR2CSA with nanomolar affinity, and it is coexpressed on the iRBC surface with VAR2CSA. Unlike VAR2CSA, which is anchored by a transmembrane domain, PfCSA-L is peripherally associated with the outer surface of knobs through high-affinity protein-protein interactions with VAR2CSA. This suggests that iRBC sequestration involves complexes of invariant and variant surface proteins, allowing parasites to maintain both diversity and function at the iRBC surface. The PfCSA-L is a promising target for intervention because it is well conserved, exposed on infected cells, and expressed and localized with VAR2CSA.

Output performance of the novel active transcutaneous bone conduction implant Sentio at different stimulation sites

The output performance of a novel semi-implantable transcutaneous bone conduction device was compared to an established percutaneous bone-anchored hearing system device using cadaver heads. The influence of actuator position, tissue growth below the actuator and mounting it on the surface or in a flattened bone bed on the performance of the implanted actuator was investigated. The percutaneous and the new transcutaneous device were sequentially implanted at two sites in five human cadaver heads: 55 mm superior-posterior to the ear canal opening (position A) and, closer to the cochlea, about 20 mm inferior-posterior to the ear canal opening behind the pinna on the mastoid (position B). The ipsi- and contralateral cochlear promontory (CP) velocity magnitude responses to percutaneous and transcutaneous stimulation were measured using laser Doppler vibrometry. In addition, the CP vibration of the transcutaneous device placed directly on the skull bone surface was compared with the placement in a flattened bone bed at a depth of about 3 mm. Finally, the influence of placing a thin silicone interposition layer under the implanted transducer was also explored. The percutaneous device provided about an 11 dB higher average CP vibration level than the transcutaneous device at frequencies between 0.5 and 10 kHz. The ipsilateral CP vibration responses with stimulations at position B were on average 13 dB higher compared to stimulation at position A. The placement of the transcutaneous transducer at position B provided similar or higher average vibration magnitudes than the percutaneous transducer at position A. The 3 mm deep flattened bone bed had no significant effects on the output performance. Placing a thin silicone layer under the transcutaneous transducer had no significant influence on the output of the transcutaneous device. Our results using the CP vibration responses show that at frequencies above 500 Hz the new transcutaneous device at position B provides similar output levels as the percutaneous device at position A. The results also indicated that neither a bone bed for the placement of the transcutaneous transducer nor a simulated tissue growth between the actuator and the bone affect the output performance of the device.

Exact solution for 1D deep bed filtration with particle capture by advection and dispersion

We consider a one-dimensional (1D) non-linear 2x2 hyperbolic problem of suspension-colloidal-nano transport in porous media, so-called deep bed filtration. The particle capture rate is proportional to the overall particle flux, which includes dispersion. The captured-particle concentration dependency on the proportionality coefficient, which is typical for large captured concentrations, causes the non-linearity of the problem. However, the 1D initial–boundary value problem allows for an exact solution. The introduction of the Riemann invariant converts the 2x2 system into a scalar quasi-linear hyperbolic equation, which is implicitly solved using the method of characteristics. The non-linear equation for particle capture rate yields a limited travelling wave that approximates the exact solution for the initial–boundary problem. • Simultaneous particle capture from advective and dispersive fluxes. • Exact analytical solution for 1D transport problem. • Dependency of the hyperbolic shock front velocity on the dispersion coefficient. • Explicit expression for the Riemann invariant.

Performance analysis of deep bed drying of canola seeds using numerical technique

Canola grain containing 18–20% moisture during harvesting is not suitable for safe storage. The storage conditions for these grains need to be optimized through drying technique to prevent both fungal attack and suppression in germination. Hence, the present investigation has been carried out to analyze coupled heat and mass transfer phenomena during steady state counter flow deep bed drying. To carry out this study, a non-equilibrium drying model has been developed. Governing equations include moisture mass balance, enthalpy balance, heat transfer rate, mass transfer rate for an element along bed height. And diffusion equation of moisture inside a single kernel has also been solved simultaneously through an implicit scheme using TDMA (Tri-Diagonal Matrix Algorithm). An iterative approach has been used to solve the governing equations for a selected geometry of the dryer. The rating analysis can be used for arriving at improved quality and higher efficiency at reasonable level of throughput. • Coupled heat & mass transfer during drying is analyzed with sequential numerical technique. • Continuous flow of rice has been studied for different parameters in deep bed dryer. • Non-equilibrium model, rather than thin layer drying, is used. • More accurate, detailed and valid results are obtained.

Evolution of welfare indicators of pigs housed in deep bedding systems during growing and finishing phases: assessment of good health principles and housing conditions

The aim of the study was to monitor the evolution of welfare indicators of pigs throughout growing and finishing phases housed in a deep bedding system by principles of good health and housing. In all, 16,500 animals, distributed in 15 facilities, were evaluated over a 4-month period. Three assessments were carried out in each facility by a single evaluator, according to the following time distribution: phase one (75 to 85days old), phase two (86 to 161days old), and phase three (162 to 180days old). Only the parameters related to good health and good housing were considered. Data were analyzed by logistic regression for longitudinal data. Poisson distribution was used on the coughing and sneezing data, with subsequent chi-square analysis. There were no cases of poor body condition, shivering, panting, huddling, tail biting, pumping, twisted snout, rectal prolapse, lameness, and skin conditions. The final evaluations were associated with greater chances of hernia and bursitis, with greater prevalence in males than in females. The prevalence of wound and manure on the body parameters was influenced by the interaction of the evaluation and animal category. The incidence of coughing and the number of animals presenting this symptom gradually increased, becoming considerably higher in the final stage of evaluation. Health-related problems change throughout the production cycle. The evaluation of a broad and reliable view on animal welfare allows for the most appropriate management of production systems using deep bedding.

Integration of geological and geophysical studies in order to mineral exploration at the Zaveh mineralization area, Khorasan Razavi Province, Iran

The copper deposit of Zaveh lies in the SE of the city of Torbat-e-Heydarieh and in middle of the Khaf-Kashmar-Bardaskan Magmatic Belt (KKBMB) in the Khorasan-e-Razavi Province. The lithology of the area consist of Jurassic and Cretaceous sedimentary rocks and Eocene volcanic units. Ore-formation is controlled by fault activity, representing vein-veinlet style E-W trending, formed within a conglomerate rich in quartz. Primary minerals are chalcopyrite, pyrite and arsenopyrite and secondary minerals contain malachite, azurite chalcocite, bornite, covellite, Cu sulphates, wad (Mn hydroxide), haematite, goethite, jarosite, limonite and (to a lesser extent) chrysocolla. The predominant alteration is silification which is associated with vein ore-formation. The volcanic units host propylitic, sericite, carbonate and silicification alterations. The ore-formation itself represents anomalies of Cu (2.1 % max), As (>1%), Sb (~105 gr/T), Pb (4371 gr/T) and Zn (1.1% max). Induced polarization and electrical resistivity (IP/RS) surveys unveil that the most chargeability anomaly corresponds to center of ore-forming vein and fault zone.The chargeability anomaly extends and amplifies with depth. The most amount of specific electrical resistance has been observed in the quartz-rich conglomerate. Interpretation of IP/RS data reveals that the chargeable source is extending in deeper beds (presumably sulphid ore-formation) which needs to be verified by boring operation. Geophysical surveys are significantly commensurate with field observations, ore-forming and geochemical data. Utilization Geophysical methods in different style of ore-deposits and interpretation of obtained information by means of geological, ore-forming and geochemistry data is considered to be a big step towards subterranean exploration and deposits modeling.

Improved operational reliability and contaminant removal in water reuse through filter upgrades

AbstractA redesign, construction, and replacement of the filters used for water reuse at a 11 million gallon per day Florida municipal water reclamation facility provided a prime opportunity to evaluate the impact of the filtration technologies on water quality, trace organic contaminant (TOrC) removal, and removal of pathogens. This study was designed to capture operational data, pathogen removal (Cryptosporidium and Giardia), and TOrC removal before the replacement of the filters using the existing synthetic media filters (SMF) and traveling bridge filters (TBF) followed by an evaluation of the deep bed filters (DBF) after construction and commissioning. The new DBF units provided substantially improved control of turbidity and total suspended solids while also significantly improving the removal of Giardia cysts (increase of >2 log removal) as compared to removal across the older SMF and TBF units and minor improvements to Cryptosporidium oocyst removal. TOrC removal was not significantly changed when comparing removal across the SMF, TBF, and DBF units nor post chlorination (chloramination).Article Impact StatementThis manuscript will be of use to the community as it provides additional understanding of public health protection in water reuse.

A self-penetration torpedo anchor with vibrational shearing

As the depths at which marine facilities are constructed increase, mooring systems have become more complex, expensive, and difficult to install, making it necessary to develop new types of anchors to replace conventional drag-type anchors. In this paper, a new anchor concept based on the application of sediment fluidization technology is proposed. The proposed self-penetration torpedo anchor has a design similar to that of a torpedo anchor but is equipped with a specially designed mechanical vibrational unit. Laboratory tests were carried out to assess the penetration behavior, holding performance, and pullout behavior of the proposed torpedo under self-induced vibration. To evaluate the effect of installation on the anchorage force, the anchoring forces were measured over different rest times following vertical arrival at designated penetration depths. It was demonstrated that the anchor is able to automatically enter deep beds at moderate penetration speeds and that it has a high holding index, with an anchoring force that can recover more than 83.2% of its holding capacity following 7 d of rest in a silty bed with median particle diameters d 50 of 31 μm. Furthermore, unlike conventional torpedo anchors the anchoring force and penetration depth of the self-penetration torpedo anchor are not limited by water depth or drop height. Because the proposed torpedo can be more easily extracted through the application of vibration, problems arising from an inability to pull the anchor out can be more readily avoided. • A deep penetration can be achieved by reducing the resistance of the seabed soil to the anchor induced by mechanical vibrations. • The application of self-penetration anchor is independent of water depth or anchor drop height. • The self-penetration torpedo anchor has a high holding index at arbitrary water depth. • The application of mechanical vibrations also eases the recovery process of the self-penetration torpedo.

Process-based modeling deriving a long-term sediment budget for the Ganges-Brahmaputra-Meghna Delta, Bangladesh

Fluvial, tidal, and combined hydro-morphodynamics interaction in a complex, seasonal, sediment transport regime has been the subject of extensive research. It becomes particularly challenging when there is limited data. The Ganges-Brahmaputra-Meghna (GBM) Delta is one example of a huge system lacking data. Bathymetric data simultaneously covering the rivers and estuaries is hardly present, let alone sequences of bathymetries or a system-wide sediment budget. Hence it is difficult to understand and predict future developments. This research aims to make a sediment budget for the GBM delta with a process-based model. It is a first-ever sediment budget simulation for the GBM system. A process-based morphological model, Delft3D, has been used to reproduce the bathymetric evolution over time and the associated sediment budget. This chapter demonstrates the possibilities for the application of a robust modeling system to assess the morphodynamic evolution and sediment budget and pathways. The Ganges and Jamuna rivers carry sediment load in the ranges of 216–1038 million tonnes/yr and 80–228 million tonnes/yr respectively. The total accumulation in the estuary system is 1150 million tonnes/yr, out of which more than eighty percent of sediment is in suspension. The model results show that about 22% of the total sediment coming into the system is deposited in the floodplains and tidal plains and causes river morphology changes. The rest of the sediment is lost to the pro-delta, to the deep ocean bed, or leaves the domain. The results also indicate that Padma, Gorai, Pussur-Sibsa, Bishkhali, Shahbajpur channel, Lower Meghna, Tentulia Channel, and Arial Khan rivers are mainly in the aggrading phase, whereas, the Ganges, Jamuna, and Baleshwar are in the degrading phase. This particular delta model offers many opportunities to compare with sediment data, where it deals with a poorly surveyed area.

Modeling of the Suspended Solid Removal of a Granular Media Layer in an Upflow Stormwater Runoff Filtration System

Upflow granular media filtration devices are widely used for stormwater runoff treatment. However, the system performance is not well characterized due to the irregular removal of suspended solid (SS) in the pretreatment (sedimentation) chamber and, hence, its irregular input to the media layer. In this regard, the performance of the granular media layer of an upflow filtration system is investigated herein by the use of various models. Due to the significant variation in the SS concentration of the influent and effluent to and from the media layer, the deep bed filtration model, the k-C* model, and the porous media capture model provide limited descriptions of the system performance. By contrast, the performance is well described using the kinetic model, the modified k-C* model using a specific deposit, and the modified porous media capture model using a specific deposit. The parameters of the latter models are shown to be in good correlation with the filtration velocity, SS removal, and specific deposit. The results suggest that modeling using a specific SS deposit can provide an accurate description of the granular media layer performance under a highly variable influent SS concentration.

ASYMPTOTICS OF THE FILTRATION PROBLEM WITH ALMOST CONSTANT COEFFICIENTS

During the construction of hydraulic and underground structures, a grout solution is pumped into the ground to create waterproof partitions. The liquid grout is filtered in the porous rock and clogs the pores when hardened. The mathematical model of deep bed filtration describes the transfer of suspension particles and colloids by a fluid flow through the pores of a rock. For a one-dimensional filtration problem in a homogeneous porous medium with almost constant coefficients, an asymptotic solution is constructed. The asymptotics is compared with the numerical solution.