Efficient Drainage Research Articles

The Effect of Variations in Drainage on Infiltration Rates in Pore Cylindrical Drainage

Inundation and floods are caused by a combination of factors including lower rain catchment areas, decreasing infiltration rates, and an uneven distribution of rainfall throughout the year, which all combine to create flooding and inundation issues. The alternative option is to install an efficient drainage system that is ecologically friendly, since in addition to its role of accommodating and draining water, it also has the additional purpose of absorbing water into the subsurface soil layer. A pore hole is created at the bottom of the drainage channel in order for the water to be absorbed. There was a desire to investigate the impact of soil texture on the rate of infiltration, therefore this research was conducted. Three kinds of soil were utilized as infiltration medium, namely sandy loam, loam, and clayey loam, all of which were found in the surrounding area. In addition, there are three variants of hole spacing, namely 16 cm, 32 cm, and 48 cm, as well as three variations of flow rate, namely 400 cm3/s, 1500 cm3/s, and 2500 cm3/s, among others. As a consequence of laboratory studies, it has been shown that the impact of changes in flow rate on infiltration discharge is inversely proportional to the flow rate, i.e., the higher the flow rate, the smaller the infiltration discharge that occurs. The reason for this is because it is influenced by the flow velocity

Active drain system with reticulated open-pore foam-surface dressing for postoperative pancreatic fistula in a rat model

BackgroundPostoperative pancreatic fistula (POPF) is one of the most harmful complications after pancreatic resection. Efficient drainage affects the clinical outcome of POPF. Inefficient drain of the fluid collection should contribute greatly to the need of additional interventional drainage, secondary morbid complications, and death. MethodsA rat model of POPF was established by distal pancreatosplenectomy. A novel active drain system (ADS) for POPF was developed by wrapping polyvinyl alcohol sponges (PVA) to an end of the drainage tube. Passive drain system (PDS), ADS and ADS with PVA were used for POPF in rat models. The volume and amylase of ascites were measured. CT scan was applied to assess abdominal fluid collection. Rats pancreatic transection stumps were stained by hematoxylin and eosin (H&E). ResultsThe volume of drainage of ADS with PVA group was less than that of PDS group and ADS group at late stage. CT scan showed obvious abdominal fluid collections in 2/8, 2/8 and 0/8 rats in PDS, ADS and ADS with PVA group separately. Macrofindings showed significant intra-abdominal adhesions and inflammation in PDS and ADS group but not in ADS with PVA group. H&E staining showed less inflammatory cells and destroyed pancreatic glands in ADS with PVA group. ConclusionADS with PVA drained ascites effectively in the rat model of POPF. The effective drainage of pancreatic juice reduced the inflammation of abdominal organs and pancreatic resection stumps, and might promote the healing of POPF.

Method for designing the optimal sealing depth in methane drainage boreholes to realize efficient drainage

The purpose of underground methane drainage technology is to prevent methane disasters and enable the efficient use of coal mine methane (CMM), and the sealing depth is a key factor that affects the performance of underground methane drainage. In this work, the layouts of in-seam and crossing boreholes are considered to analyze the stress distribution and failure characteristics of roadway surrounding rock through a numerical simulation and field stress investigation to determine a reasonable sealing depth. The results show that the depths of the plastic and elastic zones in two experimental coal mines are 16 and 20 m respectively. Borehole sealing minimizes the air leakage through the fractures around the roadway when the sealing material covers the failure and plastic zones, and the field test results for CMM drainage at different sealing depths indicate that the CMM drainage efficiency increases with increasing sealing depth but does not change once the sealing depth exceeds the plastic zone. Moreover, sealing in the high-permeability roadway surrounding rock does not have a strong influence on the borehole sealing performance. Considering these findings, a new CMM drainage system for key sealing in the low-permeability zone was developed that is effective for improving the CMM drainage efficiency and prolonging the high-concentration CMM drainage period. The proposed approach offers a valuable quantitative analysis method for selecting the optimum sealing parameters for underground methane drainage, thereby improving considerably the drainage and utilization rates of CMM.

Coalbed methane stimulation by hydraulic punching with air cannon

ABSTRACT The permeability of coal seam is one of the main factors restricting the safe and efficient production of Coal Bed Methane (CBM). In order to improve the extraction efficiency of CBM and reduce the probability of coal and gas outburst, it is of great significance to adopt artificial measures to enhance the fracture network of coal seam. In this paper, a field test of air cannons after hydraulic punching was carried out. The results showed that the gas concentration and gas flow rate were greatly improved, which indicates that the pores and fractures of the coal reservoir are effectively connected. The pure gas extraction volume increased by about 0.7–2.2 times than of non-blasting. According to the experimental results, the paper studies the action mechanism of air cannons, mainly including three aspects of action. The first is the continuous impact of air cannons, which gradually breaks the coal body around the hole, and forms a fracture network of different sizes in the coal body. Air cannon blasting performs secondary treatment on the punched holes, accelerates and promotes the creep of the coal body around the borehole to the free surface, makes the cracks develop deeper, and expands the pressure relief range. Third, it has the function of pulse gas injection to displace the CH4, which broke the original adsorption balance, promoted the conversion of the adsorbed gas to the free state. The role of three aspects ultimately achieves efficient gas drainage.

Representation of mining permeability and borehole layout optimization for efficient methane drainage

The development of a cost-effective and accurate permeability characterization method for large-scale mining overburden conditions is topical for engineering assessment of mine water and gas migration characteristics. Based on laboratory test results, a new permeability characterization method considering loading–unloading times and elastic–plastic stress evolution is proposed, which is realized by fish language embedded in FLAC 3D software. The proposed method is first compared with other available models via the inversed experimental results and then applied to evaluate the protected seam permeability-enhanced range. The COMSOL Multiphysics and FLAC data interaction is used to optimize the protected seam extraction borehole layout. It is shown that the proposed model can characterize the permeability evolution more accurately than other (elastic, damage strain) models. The protected seam stress paths have non-equal loading and unloading amplitudes in vertical and horizontal directions, while its permeability is divided into six areas and the enhanced area exceeds that of the gob. Based on the permeability zoning characteristics, the non-uniform layout parameters of extraction boreholes are quantified to achieve the identical-size layout of working faces of the protected and protective seams and reduced workload of extraction boreholes.

Characterization and Land Suitability Evaluation for Cocoyam in Southern Nigeria

The soils on diverse landforms in Ikot Esidem, Southern Nigeria were characterized and their suitability evaluated for three varieties of cocoyam. The study area was stratified into flood plains, inland valleys, gentle slopes and crest. The results indicate that sand (30-78%) dominated pedons of gentle slopes and crest while silt (25-55%) and clay (19-51%) dominated the pedons of flood plains and inland valleys. The soils of flood plains and inland valleys were moderately acid (pH 5.0-5.7), medium to high in organic carbon (6.3-20.5 g/kg) and medium to high in base saturation (BS) (46-90%). The gentle slopes and crest units were strongly acid (pH 4.0-5.1), low in organic carbon (4.0-11.3 g/kg) and base saturation (20.5-34.7%). The land suitability evaluated the flood plains and inland valleys as moderately suitable and the gentle slopes and crest as not suitable for Dasheen Type Taro. The flood plains and inland valleys were also evaluated moderately suitable, whereas gentle slopes and crest were marginally suitable for Eddoe Type Taro. Efficient water control drainage and erosion control will enhance cocoyam cultivation depending on terrain type.

Efficient Design of Road Drainage Systems

Excess surface water on roadways due to storm events can cause hazardous scenarios for traffic. The design of efficient road and transportation facility drainage systems is a major challenge. Different approaches to limit excess surface water can be found in the drainage design standards of different countries. This document presents a method based on hydraulic numerical simulation and the assessment of grate inlet efficiency using the Iber model. The method is suitable for application to design criteria according to the regulations of different countries. The presented method facilitates sensitivity analyses of the performance of different scupper dispositions through the total control of the hydraulic behavior of each of the grate inlets considered in each scenario. The detailed hydraulic information can be the basis of different solution comparisons to make better decisions and obtain solutions that maximize efficiency.

High-pressure continuous suction drainage for thoracic empyema with pulmonary fistula

Background: The treatment of thoracic empyema with pulmonary fistula (PF) is challenging and involves administration of antibiotics and efficient drainage of pus. Open window thoracostomy (OWT) is typically offered for these cases, but it has several disadvantages, notably postoperative pain that is associated with rib resection. We described six consecutive cases of thoracic empyema with PF that were successfully treated with high-pressure continuous suction drainage (HCSD) instead of conventional OWT.

Defining Road Widths in Neighborhoods – An Important Characteristic for Planning Sustainable Communities

Determining road widths while developing contemporary neighborhoods is a critical concern for planners. Though regulatory bodies have determined several standards and norms for road widths of residential communities, their suitability could be interrogated in the context of sustainable developments.A Sustainable road could be one which is not overly broad or narrow; which not only caters the traffic needs of the present day lifestyles but of the future generations too, have efficient drainage system, have potential to cater to street parking, encourage pedestrian usage and other significant features. This paper aims to discuss planning considerations that are important while deciding on suitable road widths in a residential neighbourhood.

Geochemical Characterization and Trace-Element Mobility Assessment for Metallic Mine Reclamation in Soils Affected by Mine Activities in the Iberian Pyrite Belt

The geochemical characterization of the mine deposits and soils in metal mining areas is essential in order to develop an effective mine reclamation strategy. The determination of total potentially toxic element (PTE) content, together with the application of chemical extraction procedures, can give insight into the behavior of contaminants after the application of different mine reclamation solutions, as well as identify the areas where urgent action is needed. This work presents a practical application to the evaluation of the pollution potential of trace elements in soils affected by mining activities, to be used in metallic mine reclamation. The PTE behavior was assessed by single extractions in order to simulate four environmental conditions: PTE mobility under rainfall conditions, acid mine drainage, reducing conditions, and plant uptake. The spatial distribution of contaminants in the study area was evaluated by determination of PTE total content in soil samples. Trace elements with high natural mobility, such as Zn, appeared concentrated at water and sediment discharge areas, while As, Pb, and Cu contents were higher near the mine wastes. The results obtained after the extractions suggested that the highest PTE content was extracted in the complexing–reducing medium, due to the dissolution of secondary sulfates and Fe3+ oxyhydroxides and the subsequent release of PTEs associated with those mineral phases. Reclamation strategies applied in the study area should promote efficient water drainage, infiltration, and subsuperficial water circulation in order to maintain oxidant conditions in the soil. The methodology applied in this study may constitute a valuable tool to define the geochemical constraints in metal mining areas, as well as help to develop appropriate mine reclamation solutions.

Changing friction at the base of an Alpine glacier

Repeating earthquakes are a global phenomenon of tectonic faults. Multiple ruptures on the same fault asperities lead to nearly identical waveforms characteristic for these seismic events. We identify their microseismic counterparts beneath an Alpine glacier, where basal sliding accounts for a significant amount of ice flow. In contrast to tectonic faults, Alpine glacier beds are subject to large variations in sliding velocity and effective normal stresses. This leads to inter- and sub-seasonal variations in released seismic moment from stick–slip asperities, which we explain with the rate-and-state friction formalism. During summer, numerically modelled effective normal stresses at asperities are three times higher than in winter, which increases the local shear resistance by the same factor. Stronger summer asperities therefore tend to form in bed regions well connected to the efficient subglacial drainage system. Moreover, asperities organise themselves into a state of subcriticality, transferring stresses between each other. We argue that this seismic stick–slip behavior has potentially far-reaching consequences for glacier sliding and in particular for catastrophic failure of unstable ice masses.

Rapid development and persistence of efficient subglacial drainage under 900 m-thick ice in Greenland

Intensive study of the Greenland Ice Sheet's (GrIS) subglacial drainage has been motivated by its importance for ice dynamics and for nutrient/sediment export to coastal ecosystems. This has revealed consistent seasonal development of efficient subglacial drainage in the lower ablation area. While some hydrological models show qualitative agreement with field data, conflicting evidence (both field- and model-based) maintains uncertainty in the extent and rate of efficient drainage development under thick (∼1 km) ice. Here, we present the first simultaneous time series of directly-observed subglacial drainage evolution, supraglacial hydrology and ice dynamics over 11 weeks in a large GrIS catchment. We demonstrate development of a fast/efficient subglacial drainage system extending from the margin to beneath ice >900 m thick, which then persisted with little response to highly variable moulin inputs including extreme melt events and extended periods (2 weeks) of low melt input. This efficient system evolved within ∼3 weeks at a moulin initiated when a fracture intersected a supraglacial river (rather than hydrofracture and lake drainage). Ice flow response to surface melt inputs at this site follows a pattern commonly observed in the lower GrIS ablation area, and by assuming a strong relationship between ice dynamics and subglacial hydrology, we infer that efficient subglacial drainage evolution is widespread under 900 m-thick ice in west Greenland. This time series of tracer transit characteristics through a developing and then persistent efficient drainage system provides a unique data set with which to validate and constrain existing numerical drainage system models, extending their capability for simulating drainage system evolution under current and future conditions.

Assessment of Geologic Controls of Flooding in Parts of OBIO/AKPOR L.G.A., Rivers State, Nigeria

Flooding of Municipal areas is a frequent environmental occurrence in Rivers State that occurs when rainfall runoff meets land surfaces with low water absorbing capacity or when it overwhelms drainage channels. In order to assess the flood situation in the study area, an integrated method which involves Field-measurement, Geographic information system (GIS), Laboratory analysis of soil samples and topographic studies were employed. Digital Elevation Model of the study area reveals that the flooded areas are situated in areas with elevations lower than its surrounding, thereby acting as a natural basin to retain flood waters after rainfall. Four holes were drilled to depth of 3m to obtain soil samples at 1 m sampling interval, from which laboratory analysis was carried out to determine some geotechnical parameters such as soil’s particle size, specific gravity, bulk density, porosity, moisture content, permeability and hydraulic conductivity. Results from the analysis show that permeability, hydraulic conductivity and porosity diminishes with respect to depth. The soil in the flooded areas have high fines content (silt and clay), high bulk density which increase with depth and a specific gravity that is typical of organic rich soils that contain sand mixed with a considerable amount of fines. At Nkpolu, mean permeability rates of 0.003cm/sec, 0.009cm/sec and 0.033cm/sec were obtained at 1, 2 and 3m respectively. At Eneka, mean permeability rates of 0.011cm/sec, 0.018cm/sec and 0.014cm/sec were obtained at 1, 2 and 3m respectively, while at Rukpokwu, mean Permeability rates of 0.021cm/sec was obtained at 1m, while 0.006cm/sec was obtained at 2 and 3m respectively. The Mean hydraulic conductivity for the locations under study is of the order of 10-4ft/day. This study has shown that the flooded areas are located in low lying urban areas which act as basins, therefore, the top soil is crusted with highly compacted soil horizons beneath. With high and frequent rainfall in the region which generates a lot of runoff, in addition to poor drainage system, flooding of the study area occurs frequently. Therefore, construction and maintenance of efficient drainage channels for an effective solution to urban pluvial flooding in the study area are thereby recommended.

Evolution Characteristics of a High-Level Asymmetric Fracture-Seepage Community and Precise Coalbed Methane Drainage Technology during Mining of Outburst-Prone Coal Seam Groups

The aim of this study is to explore the coupling relationship between fractures in overlying strata and gas seepage fields for pressure relief during mining of outburst-prone coal seam groups and to quantitatively characterize the distribution characteristics of favorable areas for coalbed methane (CBM) drainage in mining-induced fractures of overlying strata. For these purposes, by taking Shaqu No. 1 Coal Mine (Lvliang City, Shanxi Province, China) as a research object, this research studied migration and caving characteristics of overlying strata by combining physical similar material simulation, numerical simulation, and field measurement. Moreover, this study analyzed spatial distribution patterns of mining-induced fractures in overlaying strata, quantitatively characterized distribution parameters of asymmetric-oblique-quadrilateral fracture development zones in overlying strata, and precisely divided areas favorable for CBM drainage. On this basis, evolution laws of an asymmetric fracture-seepage community in overlying strata in outburst-prone coal seam groups were obtained, thus optimizing design parameters for directional drilling in the fracture zone in overlying strata. The research results demonstrate that, due to mining-induced influences, strata present different migration and rupture patterns along rupture lines on both sides. Because of different rupture angles α and β, mining-induced fractures in overlying strata are distributed as an asymmetric-oblique-quadrilateral fracture development body in space. Furthermore, based on the coupling relationship between fracture development states and pressure-relief gas seepage in the fracture development zone in overlying strata of the 4305 rear working face in the mine, this research obtained rupture angles α ∈ [74, 90) and ß ∈ (70, 82] on both sides of the fracture development zone. Moreover, the intervals favorable for CBM drainage for pressure relief on both sides of the fracture development zone in overlying strata of 4305 rear working face in the mine were separately determined as xaj ≤ 22.68 m and 24 m ≤ xβj ≤ 37.8 m. If the gas drainage system is designed in this zone, it is of great significance to precise and efficient pressure-relief CBM drainage in the fracture zone and ensure production safety in the mining space.

Carboxymethyl-β-glucan/chitosan nanoparticles: new thermostable and efficient carriers for antigen delivery.

In the last few decades, nanotechnology has emerged as an important tool aimed at enhancing the immune response against modern antigens. Nanocarriers designed specifically for this purpose have been shown to provide protection, stability, and controlled release properties to proteins, peptides, and polynucleotide-based antigens. Polysaccharides are particularly interesting biomaterials for the construction of these nanocarriers given their wide distribution among pathogens, which facilitates their recognition by antigen-presenting cells (APCs). In this work, we focused on an immunostimulant beta-glucan derivative, carboxymethyl-β-glucan, to prepare a novel nanocarrier in combination with chitosan. The resulting carboxymethyl-β-glucan/chitosan nanoparticles exhibited adequate physicochemical properties and an important protein association efficiency, with ovalbumin as a model compound. Moreover, thermostability was achieved through the optimization of a lyophilized form of the antigen-loaded nanoparticles, which remained stable for up to 1 month at 40 ºC. Biodistribution studies in mice showed an efficient drainage of the nanoparticles to the nearest lymph node following subcutaneous injection, and a significant co-localization with dendritic cells. Additionally, subcutaneous immunization of mice with a single dose of the ovalbumin-loaded nanoparticles led to induced T cell proliferation and antibody responses, comparable to those achieved with alum-adsorbed ovalbumin. These results illustrate the potential of these novel nanocarriers in vaccination.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s13346-021-00968-9.

Laboratory full-scale model test of subgrade mud pumping for ballastless track of high-speed railway

ABSTRACT This paper aims to clarify the mechanisms and driving factors of subgrade mud pumping for ballastless track in high-speed railway. A full-scale model test system in which the train dynamic loading and rainfall condition could be simulated was developed, allowing the recurrence of subgrade mud pumping. The relationship between the degree of mud pumping and the hydrodynamic pressure characteristics of subgrade was investigated, and the mechanisms and driving factors of mud pumping were also clarified. It was shown that the subgrade surface layer under the cracked concrete base was always saturated under the condition of rainwater infiltration, and it was prone to mud pumping given a long-term action of the dynamic loading of trains. A significant increase in excess pore water pressure to a certain extent mobilized the mud pumping. Accordingly, the prevention and treatment of mud pumping can be the prevention of rainwater infiltration or more efficient drainage.

Usefulness of Self-Expanding Drainage Cannula in Venovenous Extracorporeal Membrane Oxygenation: Tips, Tricks, and Results of an Early Experience.

Inadequate venous drainage decreases the efficiency of extracorporeal membrane oxygenation (ECMO). Pump augmentation may even make it worse due to collapse of the venous system under negative pressures. Furthermore, recirculation is a phenomenon that occurs when oxygenated blood supplied through the infusion cannula is withdrawn directly through the drainage cannula without contributing to the oxygenation of the patient and also compromises the efficacy of the therapy. Large drainage cannulas allow for similar flow rates at lower pump speed. But percutaneous insertion of these larger cannulas could be challenging. When using a self-expandable cannula, the diameter of the cannula for the insertion can be reduced, and once inserted, its intravascular diameter maximized, resulting in a large venous cannula due to in situ expansion after mandrel removal (up to 36F). We present a retrospective series of selfexpanding venous cannula 430 or 530 mm in length in six consecutive patients undergoing venovenous (VV) ECMO. No vascular or cardiac iatrogenic injury was caused during implantation. Target flows were reached, and no clinically significant recirculation was described in any case. The use of selfexpanding drainage cannulas was safe, and efficient drainage was achieved with easy and definitive unique positioning during cannulation.

Peritoneovenous Shunt for Intractable Ascites in Children: A Series of 4 Cases.

Intractable ascites is a rare condition in children mainly caused by cirrhosis or lymphatic disorders. Internal drainage may be considered as rescue therapy. In our department, 4 patients ages from 2 months to 15 years old underwent a peritoneovenous shunt (PVS) placement between 2010 and 2020. The surgically inserted device was a pumping device that enabled to drain ascites from the peritoneum into the venous system via the internal jugular vein (Denver shunt, BD Company, NJ). Immediate efficient drainage was achieved in all cases and lasted up to 9 years. Two major complications occurred: a postoperative fat embolism requiring urgent temporary ligation of the shunt and endocarditis shortly after inguinal hernia repair performed 16 months after placement of the shunt. Implementation of a PVS may be a useful procedure in patients with refractory ascites. Chylous ascites should be drained and washed totally before activating the device to avoid fat embolism. Antibiotic prophylaxis is required when abdominal surgery is planned while the device is in place.

Characteristics of Seepage and Diffusion in Gas Drainage and Its Application for Enhancing the gas utilization rate

Although gas drainage technology has greatly developed, gas concentration and utilization rates are still very low, resulting in substantial quantities of low concentration gas emissions in coal mine. To study the roles of suction pressure on gas drainage, a mathematical model is developed in this study for coupled gas migration and coal deformation based on a dual-porosity medium. The simulation results reveal the initial gas production is mainly contributed by the seepage in the fracture, and then the dominating factor rapidly transitions to diffusion which provides relatively stable gas production in most drainage time. In addition, the increase in gas production is tiny while the gas concentration clearly decreases because of air leakage as the suction pressure increases. Therefore, a concentration-based suction pressure regulating method is proposed to extend the time period of effective gas drainage and increase the gas utilization rate through adjusting the suction pressure of the bedding borehole. Field tests were performed to constrain the gas drainage process under different suction pressures, and the results gained verify the effectiveness and applicability of this method. This study proves that the concentration-based suction pressure regulating method may be a promising technology to realize safe, economical and efficient underground gas drainage in coal mines in the future.

Mineral Trespass: Expanded Regulation in the Wake of Technological Advancement

Technological advancements in the oil and gas industry have created challenges for courts and the Texas Railroad Commission regarding how to properly balance the protection of lessors and lessees, while also furthering the public interest of maximizing production. The Texas Railroad Commission currently does not have regulations in place to protect mineral lessors or lessees with respect to spacing between separate leases covering different depths in the vertical plane within the same tract. Without correct spacing regulations from the Railroad Commission, an operator’s production within deeper strata cannot be properly analyzed by courts in trespass actions. The move from vertical to horizontal drilling has enabled operators to use technologic advancements, such as hydraulic fracturing, to obtain oil, gas, and other hydrocarbons that were once thought unattainable. Mineral owners have been given opportunities through oil and gas lease clauses, such as the Pugh clause, to sever their mineral rights and create separate leasehold estates within the same tract of land. Requiring operators to adhere to expanded Rule 37 spacing requirements in the vertical plane would help reduce subsurface trespass claims. The Texas Railroad Commission should expand Rule 37 to apply to horizontal severances in the vertical plane, as well as offset lease lines. Courts should reshape subsurface trespass analyses by balancing multiple factors. In the absence of clear and convincing evidence of a physical intrusion, future courts should analyze and balance the following factors for subsurface trespass claims: (i) public interest in exploration, or the interests of society; (ii) speculation versus evidence of a physical intrusion based on a reasonable and prudent operator standard; (iii) the degree of waste from allowing production versus not allowing production; and (iv) harm to the geologic formation. The proposed spacing regulations would have positive effects on all parties to an oil and gas lease by mitigating subsurface trespass claims, creating efficient drainage, and preventing both surface and economic waste. Further, courts have yet to address the issue of subsurface trespass and the impact of the rule of capture regarding multiple wells drilled on the same tract in the vertical plane. In the absence of adequate spacing requirements in the vertical plane, courts should employ a holistic analysis for subsurface trespass claims and consider multiple elements rather than solely the public interest.