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Delaware River Main Channel
In 2008 June, a contract was signed between the US Army Corps of Engineers and Port Authority of Philadelphia Regional to commence a $379-million deal that aimed to increase the depth of the Delaware River's shipping channel and was estimated to take a period of 5 years to complete (Kauffman 1662). According to the proposal, the deeper end of the channel was 40 feet, and this depth was to be increased to 45 feet. The deeper channel would permit Delaware River ports to remain competitive and efficient in cargo transportation, offer secure passage, and create more job opportunities within the region.
Determination Of Beta Particle Energy
Determining the energy produced by the beta particles when an unstable nucleus decays is important in the field of nuclear physics as it helps in the characterization of the radioactive materials for better disposal. One possible solution to measuring low energy beta particles is attaching a beta emitter onto a detector. In this experiment, a NaI scintillation detector is used to determine the energy of the beta particles produced when 128I decays to 128Xe. The energy is obtained by analysing the endpoint energy from the beta decay spectrum. Additionally, the half-life of the 128I is calculated from the graph of ln (N/T) vs Time (s). The results from the calculations estimate the half-life to be 25 minutes and the endpoint energy to be 0.0022 Uma.
Hydrofracking
Hydrofracking, also known as hydraulic stimulation or fracturing, is a fluid injection process under high pressure into a coal seam to create new fractures and widen existing ones (Osiptsov, 2017). For example, a proppant is combined with the injected fluid (water) and made to flow through the existing fractures. The sand is essential in keeping the fractures open after completing the fracture treatment and release of pressure. The widened or created fractures generally have a thickness of between 1 mm and 20 mm. Hydrofracking is done sequentially at various stages or depths in a well according to the positioning of the coal seams. Sometimes, hydraulic stimulation may be repeated during a well's life to boost gas's declining productivity. Figure 1: Hydraulic Stimulation The history of hydraulic stimulation started in 1949 in the gas and oil industry in the U.S. Initially, kerosene or crude oil was used as the injection fluid. Hydraulic stimulation has since then been performed at least 2.5 million times on average, globally. Hydraulic stimulation is essential as it allows gas extraction up to ten times faster than from un-stimulated wells. Fracking also adds to shale gas extraction's expense and is mostly performed if the economic viability of the gas extraction from a well minimal. The fracture network's penetrability generally reduces during the production process as the proppant is flowing back to the well. Extreme proppant back back may lead to the closing up of fractures. Fracture damage may also occur after embedment or crushing of proppant into the bedrock cracks, from mineral precipitation in the fracture and well-plugging perforations. The growth of hydraulic fractures of propagation occurs in the direction that is least resistant. Fracture propagation is dependent on the conditions of the site, including factors like stress magnitude and geology (Clarke, 2014). Fracture growth may be difficult to predict due to changes in the minimum resistance path with respect to the rock's mechanical properties. The path with minimum resistance may also change due to the rock's stress regime of forces and the natural configuration of already existing fracture. In-site measurements of stress can be used in determining the regional and local trends for the directions of stress to predict the hydraulic propagation course. Figure 2: Natural Coal Fracture Network Example 2 Hydraulic Stimulation Stages Hydraulic fracturing occurs in three main stages, including pre-fracturing assessment, perforation, and post-fracturing activities. 2.1 Stage 1: Pre-fracturing Assessment Operators perform subsurface investigations to come up with the program design for hydrofracking stimulation in the course the pre-fracture evaluation. Subsurface evaluation helps in understanding coal seams' mechanical and hydrogeological properties and the surrounding units. The main elements of subsurface characterization include all geological units' description, coal seam permeability assessment, subsurface faults and stresses distribution, and natural fractured coal's fluid loss assessment. The fracking design program also involves fracture increase prediction within the targeted area. Hydraulic simulation program is used in fractures' geometry prediction while in situ stress field is applied to determine the orientation. Typical numerical models' inputs include proppant and fluid properties and volume, closure stress, coal seam internal pores' pressure, permeability, and layer geometry. 2.2 Stage 2: Onsite Activities Onsite activities include site setup, well casing perforation into the targeted shale gas, hydraulic stimulation fluid injection, and injected liquid flow back. The setup of the site involves use of temporary storage facilities in containing the water source for stimulation and fluid flow back. Purpose-built mobile units may be used for onsite materials such as chemicals and sand, storage, and fracturing fluid blending. Perforation includes making small holes with a diameter of between 5 and 15mm through the well casing and cement at the shale gas or coal seam targeted area depth. Afterward, particles (proppant) and fluids are injected into the well to start stimulation in the coal seam region. Injection of proppant and fluids aids in keeping the fractures open to enable the flowing of water and gas to the well. 2.3 Stage 3: Post-fracturing Activities Post-fracturing activities include growth measurement and monitoring of the environment. Fracture growth measurements are performed after fracturing treatment. The results of fracture growth measurements are then used in improving predictions for future fracking. Fracture propagation measurements can be done through various methods, including radioactive tracer detection, temperature surveys, production downhole or logs video, and microseismic and tiltmeter mapping. The fracture growth measurement approaches can only evaluate the height of the fracture in the well's immediate surrounding area. Tiltmeter mapping encompasses measuring the small bends caused by fracturing. Microseismic mapping consists of the measurement of minimal earthquake events that occur during fracturing. Microseismic events may be caused by coal and adjacent rock stress from high-pressure fluid injection and hydraulic fractures' opening. Sensitive seismic measuring instruments are used in every event detection by determining the time stress waves take to travel from the event point to the receiver. Figure 3: Microseismic Fracture Growth Monitoring Hydraulic fracturing impacts include surface water, aquatic ecosystems, and resources' contamination, induced seismicity, and increased water use. Hydraulic fracturing may also affect the quality and quantity of groundwater resources. Hydrofracking impacts should be monitored to define a baseline before, in the course of, and after the activity of stimulation. The well integrity and area surround is scanned for any changes after the fracturing process. Pressure ground techniques are used to test well integrity. Cement bond logging (CBL) equipment is run in well to examine whether the cement still remain intact or not. Groundwater analysis for various contaminants, including methane, is done both before and after fracking. Presence of methane in the groundwater comes from various sources, i.e. the anthropogenic and natural sources. Failure to collect baseline data before the fracking process may make it difficult to determine whether the methane detection in groundwater resulted from the fracturing process. Researchers use stable isotope analysis using Deuterium and Carbon 13 or radiocarbon dating to determine whether methane formation was due to biogenic methane bacteria. The methane formed may also be due to high temperatures and pressures, thus known as thermogenic methane. 3 Main environmental impacts of hydraulic fracturing The development of hydraulic fracturing will have to take into account several environmental impacts. 3.1 Risks during drilling As indicated above, it is necessary to employ special drilling techniques in order to be able to subsequently proceed with hydraulic fracturing. Consequently, the specific risks of diverted wells are in addition to the usual risks associated with drilling for hydrocarbons (Osiptsov, 2017). These risks include explosion, leakages of hydrogen sulfide and other gases (hydrogen sulfide really poisonous in low concentrations), and landslides formation on the casing. The latter are much very common in the case of where wells are deviated, which is usually used in hydraulic fracturing. It should be remembered that on average six to eight wells are drilled per platform and that there are between 1.5 and 3.5 platforms per km 2. This is why, although the risk of such an accident occurring per well is a priori low, it increases alarmingly with the increase in the number of wells to be drilled. 3.2 The water pollution One of the main worries around hydrofracking is its effect on underground aquifers. When fracking the subsoil, there is a likelihood that at least one of the fractures induced by hydrofracking will extent to an aquifer zones, thereby causing pollution the water as a result of fracking fluids and gas formation. In addition to this risk, contact with an old poorly insulated well is also possible. The gas then easily enters the aquifer and rises to the surface. This type of accident has happened in the past, as in the case of Pavilion, Wyoming. 3.3 Chemical risks associated with additives As aforementioned, each borehole requires the use of some 400 tonnes of chemicals, most of which are highly polluting. Diluted at 2% in water, their level of toxicity is greatly reduced. However, these chemicals are transported to the platform undiluted. The threat of accident occurring during the transportation should be put into consideration. The number of truck transports to be carried out for the density of drilled wells is high (which also causes noise pollution and road insecurity). For each platform, the number of truck trips is estimated at least 4,000, many of which are used for transporting chemicals, which can considered a serious concern as far as environment is concerned. 3.4 Air pollution All through the penetration and fracking process, large volume of additives are utilized, majority of which comprise of highly volatile elements. The same is applicable to the production step, during which the conditioning of the extracted gas is required in order to inject it into the gas pipeline. All these elements pass in smaller or larger quantities in the atmosphere and can for example generate ozone or BTX (benzene-toluene-xylene). 3.5 Earthquakes In regions where there huge development of hydraulic fracturing infrastructure, a resurgence in seismicity concurring with phases of hydrofracting activities has been observed. It should be noticed that during hydraulic fracturing operations, the subsoil is subjected to pressure over hundred times. This overload to which it is subjected may be sufficient to cause activities of underground faults and as a result earthquakes. An example of this case was noted in Lancashire, United Kingdom, where the firm Cuadrilla Resources admitted that it was hydrofrackking had caused two local earthquakes. 3.6 The greenhouse effect Unconventional gas, given the state in which it is obtained, usually comprises methane almost entirely. The latter is a greenhouse gas which considered more toxic compared CO 2 itself, it is 23 times powerful. This means that any leak of this gas in the course of drilling and fracking process is much more dangerous than the gases that are then produced during its combustion. The other problem with hydrofracting methods regarding gas leaks is the fracturing water as it rises to the surface. Since it has had interaction with the gas existing in the subsoil, it can be considered to have absorbed the gas which, upon rising to the surface, is released to the air. It is projected that, for a well in which a hydrofracting has been performed, the upsurge in methane emissions is 2%. A research finding from Cornell University thus approximates that shale gas causes in a rise in greenhouse gas (GHG) releases from 30% to 100% as compared to gases from coal burning. 6.7. Land occupation Added to this is the problem of the extensive need for land occupation in this type of exploitation. As indicated previously, it is indispensable to make a several large volumes of wells in order to appropriately extract the resources. The fracturing companies generally drill around 3 platforms, with each platform occupying 2 hectares. Therefore, the physical effect of this gathering of wells is very important. 4 Hydrofracking Past Events Hydrofracking for shale gas has hugely revolutionized natural gas production in the United States (US). Over the last few decades, t has transformed the country to an exporter from an importer. Other nations have appeared to follow suit with industrial-scale productions production, they include Canada, Argentina, Colombia and China. In other part of the world, including UK, shale gas resources extraction have been found and permits distributed, however only a few wells have been drilled so far. In the UK hydrofracking for shale gas has drawn strong criticism from the public as well as environmentalists, this is attributable to possible hydrofracking-induced earthquakes in first ever drilled shale gas. In 2011, the consequence of fluid injection Lancashire was two felt earthquakes and this caused in a temporary ban of the operations in the region. 4.1 Pennsylvania hydrofracking Accident A Pennsylvania gas well which was being operated by Chesapeake Energy exploded sending several gallons of highly saline and chemical-laced water from the drill site to the containment berms, running towards the popular trout-fishing stream and compelling families neighboring the area to temporarily vacate their households (Currie, Greenstone, & Meckel, 2017). It's the most recent and perhaps the most severe hydrofracking-related calamity in the contentious seven-year quest to obtain natural gas from the Marcellus Shale. This was the US’s highest natural gas fracking target and underlying larger parts of Ohio, West Virginia, Pennsylvania, and New York. From this event, the Department of Environmental Protection (DEP) of Pennsylvania believed the basis of the accident, which happened almost a year after the Deepwater Horizon BP drilling rig explosion which occurred in the Gulf of Mexico, was seemingly a combination of bad luck: engineering system failure together with bad weather. 4.2 Hydrofracking-induced earthquake in UK In 2011, test operations near Blackpool were banned after tremors with a magnitude ranging between 1.5 and 2.2 were discovered. Inquiries performed after this established that it was ‘very probable’ that the fracking had triggered the earthquakes and therefore ‘traffic light’ guidelines were presented at fracking locations all over the country. British Geological Survey (BGS) made a suggestion that tremors were related to the Cuadrilla’s hydrofracking undertakings. According to Clarke (2014), two geologists wrote report that provided details and models demonstrates how hydrofracking could be the key culprit triggering the earthquakes. The report from Cuadrilla, who were operating the site indicated the reason for the tremors were a rare blend of circumstances: the fault was at present under stress, was sufficiently brittle crack and had space for larg ewater volumes for lubrication. Cuadrilla were suggesting to observe the seismic activities within its fracking location. The proposal was that if tremors is noted, they would decrease the water flow into the well, or even pump them out to avert the occurrence of high magnitude earthquakes. 4.3 The Sichuan Basin of China In the southern Sichuan Basin, China, the current resurgence in the occurrence seismic events has been assumed to be associated with hydraulic fracking stimulation used in extraction of the shale gas. According to Tan et al. (2020), the findings of seismic velocity tomography showed that triggering of previously existing faults as a result of fluid diffusion was the chief cause of the witnessed earthquakes. Focal mechanism research pooled together with geomechanical modeling suggests that the elevated pressures in pores brought about by hydraulic drilling are adequate to cause fault lines seismic slips. 4.4 Fracking contaminated underground water in Wyoming There was reports that Wyoming-Upper Green River Basin indicated to have ozone levels that were higher than those of Los Angeles. The Wyoming Department of Environmental Quality took an initiative of urging the children and elderly to keep off persistent out-of-doors activity (Colmenares & Zoback, 2007). After getting grievances from Pavillion populations about the drinking water’s having bad smell and taste, the Environment Protection Agency (EPA) commenced an enquiry in September 2008 concerning the matter. EPA sampled domestic wells in March 2009 and January 2010 and released a preliminary study in 2011. The study found that the chemicals used in the fracturing process had spilled into Pavillion's groundwater from unlined dumping pits. The fracking industry has fought back against the report and the EPA has never finalized its conclusions. Instead in 2013, the Department handed over the case to the state of Wyoming, which has since released further inconclusive findings. 4.5 Arkansas US earthquake The US Geological Survey recorded over 800 earthquakes in central Arkansas in a period from September 2010 to January 2011. Earthquakes were noted have triggered disruption to homes, such as wall cracks and driveways. Geologists attributed the earthquakes to hydrofracking’s liquid waste disposal in injection wells. 5 Alternatives of hydraulic fracking Two other avenues are explored, at least prospectively. These are electrical and thermal processes. 5.1 Electric arc fracturing Electric arc fracturing consists of going from a static stress of the rock to a dynamic stress, in order to fragment the material in such a way as to create a very dense - rather than very extensive - network of cracks (Northrup, 2010). The load applied to the rock is a pressure wave produced by the discharge of electric currents between two electrodes positioned in the borehole, fully occupied by water. The duration of emission of this wave is of the order of a 100 microsecs. This wave is transferred to the rock or coal seam by the fluid existing in the well. It creates a microcrack whose density decreases as one moves further from the well. This approach will hugely reduce the earthquakes and contamination that is related to fracking. 5.2 Thermal fracturing Heating processes have already been used by the petroleum industry to improve the rate of recovery of oils or to accelerate the maturation of organic matter, in the case of oil shales for example. Fracturing by thermal effect consists in heating the rock from either steam (without fracturing) or from an electric type heating. This heating makes it possible to dehydrate the rock, which leads to a retraction and therefore to a cracking of the latter. The space released by the water increases the porosity and therefore the permeability of the rock. 5.3 Pneumatic fracturing Pneumatic fracturing involves injecting compacted air into the well to crumble the bedrock by applying shock waves (Osiptsov, 2017). These shock waves are generated by devices such as compressed air guns. Helium is used in this approach. Helium is liquid when it is injected, but fracturing is caused by the strong expansion of the gas as it warms up in the subsoil, which is why this technology is classified under in the category of pneumatic fracturing. 5.4 Stimulation from liquefied or gelled gases The fracturing liquid can be formed from other liquid gases: helium (mentioned above), carbon dioxide (CO 2) or nitrogen, which make it possible to develop low viscosity fluids, potentially more efficient than water in extracting hydrocarbons from their parent rock. These liquid gases can be used alone or with additives in order to form foams. These alternative fluids have already been used in the United States and continue to be the subject of research. Liquid CO 2 fracking technologies have already been used many times in the United States and Canada. It is therefore a known process, although it can evolve. By the late 1990s, more than 1,200 CO 2 fracturing operations had been carried out in Canada. 6 Advantages and disadvantages of the main alternative techniques Principle Advantages Disadvantages Electric fracturing - Arc : create an acoustic wave in the well near the reservoir, using an electric arc - Another process called HPP : sending pressure pulses from the well to break up the rock Low water usage No additives At the R&D stage Can only stimulate the immediate proximity of the well and therefore insufficiently effective Fracturing with methanol or diesel No use of water Low number of additives Operational technique Surface hazards (spill, explosion) Risk of contamination in the event of leakage of the well Propane stimulation No use of water Low number or even absence of additives Little or no reaction with the substrate Operational technique Additional surface infrastructure Surface risks (explosion) Risk of contamination in the event of leakage of the well Use of cryogenized helium as base fluid: strong expansion of the gas during its heating in the subsoil No use of water At the R&D stage Costs Procurement Does not allow the use of proppant Use of nitrogen as base fluid No use of water Low number of additives Already applied Depth restriction Low volume of stimulated reservoir Does not allow the use of proppant Need strong compression capacities Use of CO 2 as base fluid No use of water Low number of additives Already applied Low volume of stimulated reservoir Possible temperature limitation Cost of CO 2 Release of CO 2 Use of glycol Risk of reaction with the substrate (H 2 S for example) Use of foam (stable emulsion between water and a gas: CO 2 or nitrogen) Reduce the amount of water Improve proppant transport Better penetration in training Need for additives (surfactants) Need for greater transport Larger infrastructure Requires the use of CO 2 (emissions) Cost of CO 2 Risk of CO 2 reacting with the substrate (H 2 S for example) Need high compression capacities (nitrogen) Risks associated with surface gas storage. Pneumatic fracturing (compressed air) No use of water Compressed air transport In the case of helium: rare gas 7 Recommendations There is consensus on the several risks accompanying the use hydraulic fracturing: water usage, treatment of the surface, aquifers’ contamination, and seismic activity induced by fracking, and release of methane gases (methane puffs during the settling of surface water) (Clarke, 2014). After evaluating the available alternatives that can be used in future: 7.1 Changing the fluid The fracturing fluid penetration within the existing cracks network is directly depended on on its viscosity. It can therefore be viable to think that reducing the viscosity of the fluid (Water) can enable fluids to penetrate more effortlessly in the crack already existing cracks and exerting sufficient pressure to reactivate them (Osiptsov, 2017). There are several option to select in finding the right fluid: propane, carbon dioxide, nitrogen, and so on. The viscosity of carbon dioxide in its liquid state is 10 times lower that that than water normal. On the other hand, Nitrogen is eco-friendly for the environment, and application of CO2 can aid in storing it at the same time. This will be enable the hydrofracking engineers to avoid water contamination in future. 7.2 Using Non-flammable propane (NFP) To reduce the risk of pollution on the surface and in the subsurface, it is necessary to eliminate any chemical additive. This is the case when injecting pure propane, a technique successfully tested in December 2012 in Texas (Currie, Greenstone, & Meckel, 2017). The viscosity of pure propane being too low to transport standard sand, it is necessary to resort to specific materials (porous ceramic or alloy of polymers) light but resistant, today still not very widespread in industry. The other criteria are not degraded compared to the use of a gelled propane. If the operational risks at the surface are reduced compared to the previous case due to the fact that the rapid vaporization of pure propane reduces the operational risks on the drilling site, they nevertheless remain problematic. Also, to mitigate these operational risks, a propane non-flammable proppane is used. Several products on the market can play this role, including heptafluoropropane (HFP), a molecule derived from that of propane (C3H8) in which 7 of the 8 hydrogen atoms (H) present are replaced (hence "hepta" ) with a fluorine atom (F). It only decomposes at high temperature (640 ° C). Non-ionizable, it does not dissociate in water, its solubility is low (0.23g / l). Stable in an aqueous medium, it is also stable with respect to metals and elastomers under ambient conditions. Not very reactive, it has no toxic effect on the environment or human health, except at high concentrations (risk of asphyxiation). It is a product not classified dangerous for human health. Moreover, HFP does not destroy the ozone layer. 7.3 Electric fracturing Electric fracturing uses electric arcs that induce pressure waves and fracture rock. At least two teams are working on the subject in Texas and China. The technique works relatively well but the cracks obtained are short. It would therefore be necessary to multiply the number of wells whereas the operators wish, on the contrary, to limit the impact on the ground. 8 Conclusion Hydrofracking, also known as hydraulic stimulation or fracturing, is a fluid injection process subjected to high pressure into a shale gas zone to create new fractures in coal seam and widen existing ones. The technique consists of drilling a horizontal or vertical well, cased and cemented, at a depth of more than 2500 meters, with the aim of generating one or more high permeability channels via the injection of high pressure water, so that overcomes the strength of the rock and opens a controlled fracture at the bottom of the hole, in the desired section of the hydrocarbon containing formation. The technique has been noted to have substantial environmental impacts as evidence by a number of failure and events related to the technique. Research are working to find more other ways of reducing the impact caused by hydrofracking. It is recommendable to reduce the amount of water and additives used, use non-flammable propane (NFP), and alternatively applying electric fracking techniques. 9 References Osiptsov, A. A. (2017). Fluid mechanics of hydraulic fracturing: a review. Journal of petroleum science and engineering, 156, 513-535. Northrup, J. L. (2010). The Unique Environmental Impacts of Horizontally Hydrofracking Shale. Otsego 2000, 2-5. Tan, Y., Hu, J., Zhang, H., Chen, Y., Qian, J., Wang, Q., ... & Nie, Z. (2020). Hydraulic Fracturing Induced Seismicity in the Southern Sichuan Basin Due to Fluid Diffusion Inferred From Seismic and Injection Data Analysis. Geophysical Research Letters, 47(4), e2019GL084885. Colmenares, L. B., & Zoback, M. D. (2007). Hydraulic fracturing and wellbore completion of coalbed methane wells in the Powder River Basin, Wyoming: implications for water and gas production. AAPG bulletin, 91(1), 51-67. Clarke, H., Eisner, L., Styles, P., & Turner, P. (2014). Felt seismicity associated with shale gas hydraulic fracturing: The first documented example in Europe. Geophysical Research Letters, 41(23), 8308-8314. Currie, J., Greenstone, M., & Meckel, K. (2017). Hydraulic fracturing and infant health: New evidence from Pennsylvania. Science advances, 3(12), e1603021.
Carbon Fibre Reinforced Composite
The use of composite materials is growing rapidly, implanting itself in a wide variety of industrial sectors, this is attributable to its magnificent mechanical properties, such as its low density, light-weight, resistant, ductile and high temperature resistant materials. Composite carbon fiber materials in polymeric matrix, currently have a wide field of applications, in the aeronautical, automotive and medical industries. Taking into account that every day the opportunity to optimize the design of composite materials grows, it can be affirmed that it is necessary to know the mechanical properties of the materials to be built.
Biotechnology Of Biosensors
The field of biotechnology has witnessed significant progress in biosensors technology involving nanotechnology, electrochemistry, and bioelectronics. Besides, biosensors' performance has evolved from electrochemical to nanotechnology in order to enhance sensitivity, detection, and selectivity. With the advancement in technology, biosensors' use has increased rapidly, and they can be used to detect what traditional sensing systems could not.
Application Carbon Nanotubes (CNTs) In The Field Of Medicine
Carbon nanotubes (CNTs) comprises of carbon allotropes, such as diamond, graphite or fullerenes. There are different types of CNT's depending on the graphite layers that form them, they can be either single-walled carbon nanotubes (SWCNTs) or multiple-walled carbon nanotubes (MWCNTs. Over the past few year, CNTs have acquired great importance due to the different chemical and physical properties they present, such as high hardness and resistance, all this thanks to their chemical nature, in addition to presenting high electrical and thermal conductivity. Due to its chemical nature, this type of carbonated nanostructures can have varied applications in different areas, which can range from technology to medicine, however this type of nanostructure has the disadvantage of its poor dispersion, producing agglomerates. The objective of this document is to present the importance of CNTs in medical field, as well as the different ways of surface modification and their possible applications in areas of current interest.
Mixing Bleach And Vinegar For Cleaning And Disinfection
The cleaning and disinfection of a kitchen is part of the food safety practice that ensures products cooked or handled are not contaminated. The preparation of food inadequate hygienic-sanitary conditions requires the cleaning and disinfection of work surfaces, both those that come into direct contact with the final product, as well as those that don't come directly into contact in the handling, processing, and storage.
