Polyvinyl Chloride Pipe Research Articles

Experimental investigation on pipe-soil interaction due to ground subsidence via high-resolution fiber optic sensing

Understanding the pipe-soil interaction is critical for the design and safety assessment of buried pipelines subjected to large differential ground motion. Laboratory model tests were conducted to study the mechanical response of polyvinyl chloride pipes to ground subsidence. The optical frequency domain reflectometry technique was employed to perform distributed strain sensing of the pipe-soil system. An analytical method was proposed to estimate greenfield settlements in terms of fiber optic strain measurements. The pipe-soil interaction mechanism due to ground subsidence was investigated concerning four aspects, i.e., displacement profile of the pipe-soil system, pipe bending, soil arching, and interfacial shearing. Accounting for three-dimensional soil arching effects, a limit equilibrium solution for the earth pressure imposed on the pipe crown was given. This solution was developed from the two-dimensional Terzaghi soil arching theory and was validated based on the measured earth pressures. The feasibility of distributed fiber optic strain sensing technique in monitoring pipe-soil deformation was discussed through the comparison with the data of displacement transducers. In addition, the change in relative pipe-soil stiffness with increasing ground movements was studied based on the bending behavior of the pipe. A simplified method was given for quantifying the axial pipe-soil interaction based on longitudinal strains. This paper presents new inspiration on the intricacies of pipe-soil interaction using high-resolution distributed fiber optic sensing, which can be applied to structural health monitoring and optimum design of buried pipelines.

Reduction of Carbon Emission Is Optimized During the Life Cycle of Commonly Used Force Main Pipe Materials

With increasing attention to global warming and greenhouse gas (GHG) emissions and providing a better environment for coming generations, there is a critical need to quantify and decrease the environmental impact. Underground construction projects are one of the biggest constructions in North America; consequently, it is one of the GHG emissions' primary sources. This research focused on optimizing the carbon dioxide (CO2) emissions for a 91 cm (36 in) diameter sewer pressure pipe with 3 m (10 ft) depth and 30 m (100 ft) length, operating at 690 kPa (100 psi) during the commonly used pipeline materials' life cycle: Cured-in-Place Pipe (CIPP), Pre-stressed Concrete Cylinder Pipe (PCCP), High-density polyethylene (HDPE) pipe, and Polyvinyl Chloride (PVC) pipe. The life operations for this study were considered 100-years. The four phases of a pipeline life cycle included in this study are fabrication, installation, operation, and disposal phases. Life cycle assessment (LCA) is a methodology to evaluate the environmental impacts of products or service systems throughout the complete life cycle from the cradle to the grave. The study results show that the CO2 emissions have been reduced by 16% on the PCCP pipe, 4% on PVC pipe, 1% on HDEP pipe, and by 3.2% and 2.0% on CIPP lining (50 years and 100 years life expectancy, respectively). It is recommended that field studies be conducted in future research to obtain the necessary data to overcome the dependence on assumptions made in this study. Also, I recommended including the direct and social costs, which will make the decision easier for engineers and decision-makers to choose the right choice.

Development and Evaluation of a New Effective Tool and Method for Assessing Varroadestructor (Acari: Varroidae) Mite Populations in Honey Bee Colonies.

A new device for assessing Varroa destructor (Anderson-Truman) mite infestations in honey bee colonies was designed, tested, and evaluated against the sugar roll method, a widely used method by beekeepers. The Varroa Shaker Device (VSD) is constructed of polyvinyl chloride (PVC) pipe that separates into three parts. Inside the shaker there are two mesh sizes; the larger mesh separates the bees from the mites, and the smaller mesh captures the mites. The VSD can be used by shaking bees with only water as the wash solution. The recovery of mites using the VSD is >90%, which is such as that recorded for using the sugar roll method. Our tests demonstrated that the VSD accurately assessed mite loads when fewer than 250 bees were sampled and shaken with 250 mL of water for one minute. To assure accurate mite counts are achieved with any sampling device, honey bees should be taken from frames with an open and/or capped brood where the mites are more likely located. The VSD can be used in both laboratory and field settings to accurately assess honey bee colonies for levels of mite infestation or for collecting live mites for research purposes.

Effect of background tank color in combination with sand substrate and shelters on survival and growth of Scylla tranquebarica instar

Effect of tank color in combination with substrate-shelters on the survival and growth of the instar of purple mud crab, Scylla tranquebarica (initial body weight of 28.7 ± 2 mg) was investigated. Ten treatments were tested in triplicate with black (B) and white (W) tanks were set as the control, while other tanks were provided with a combination of sand substrate (S), and/or polyvinyl chloride pipes (P) as horizontal and nets (N) as vertical shelter, referred as B, BS, BSP, BSN, BSPN, W, WS, WSP, WSN and WSPN, respectively. Survival of the instar in black tanks (26.7 to 60.0%) was higher than in white tanks (20.0 to 46.7%) (P = 0.052). Survival in the horizontal shelter treatments (46.7 and 63.3%) exceeded that in the vertical shelter groups (30.0 and 50.0%) (P = 0.068). The final body weight of the instar in black tank (2.4 to 3.8 g) was significantly lower than white tank (2.6 to 4.8 g) (P = 0.02). Specific growth rate was significantly greater in sand substrate treatments (8.4 to 9.1%/day) than in controls (7.9 and 8.0%/day) (P = 0.015). In conclusion, horizontal shelter was better than vertical type, and black tank with substrate and horizontal shelter was more suitable for culture of purple mud crab instar.

Experimental studies on natural bank type heating/cooling energy saving Air conditioning system

The present study reports air-based novel energy saving compact bank type earth air heat exchanger system (EAHE) (having only 25m2 area) fabricated from Polyvinylchloride pipes of nominal diameter 0.203 mm (8 inches) for inlet and outlet headers and main pipes and 0.150 mm (6 inches nominal diameter) for branched pipes, which is installed in Shaheed Bhagat Singh State University, Ferozepur in Punjab state, India (North West border area of India) and studied for the duration from April to August 2021 using the full factorial design with four inlet variables at multilevel to find a model equation between inlet and outlet variables, i.e., heat exchanger effectiveness and achieved temperature difference. An induced airflow mode has been used to provide near-uniform flow through all corresponding pipes of symmetrical-shaped earth air heat exchangers. The values of Dry bulb temperature (DBT) and wet bulb temperature (WBT) have been measured for air inlet, for air outlet, as well as for ambient air using resistance temperature detectors (RTD) installed at the requisite locations. Earth's undisturbed temperature (EUT) was also noted by installing RTD at a depth of 2 m, and the average measured value of EUT is found to be 28.5°C. The current system has imparted the temperature difference variation from 0.4 oC to 9.4 oC, and the effectiveness varied from 0.16 to 0.82 during the whole season. This system could give a cooling potential of 0.0523 kJ/s to 1.587 kJ/s using a mass flow rate of 0.163 kg/s.Experiments have been designed methodically to apply the full factorial technique. Most favorable parameters have been found for hot and dry and hot and humid weather. The current study is novel in terms of significantly improving the effectiveness of EAHE and addressing the central issue of space limitation in urban areas.

Development of Kelvin/Zisman Probe Based Methodology for Detection of Minor Water Leaks in Underground Pipelines

Pipelines are the main means of transportation for liquids such as fresh water. Maintaining the pipelines in a healthy condition is essential to avoid leakage that could affect the economy, environment, sustainability, health and safety. Therefore, valuable water must be well managed and saved by detecting the minor leaks before outrageous losses. The objective of this research is to develop a Kelvin/Zisman probe (KZP) based methodology to detect water leaks in underground supply pipelines. A KZP measures the presence of moisture in soil by assessing the electric potential value (E) in volts that is set-up by the probe. It is designed to detect minor leaks especially in polyvinyl chloride (PVC) and metallic pipes such as steel pipes (ANSI Schedule 40). The developed KZP passes above the ground surface (soil) to take the potential value readings. The reading results confirm the KZP is sensitive to the moisture; so, it can detect water content of soil with 6.7%, 5.6%, and 5.2%, but cannot detect 4.6% or less. Accordingly, the reading results of water contents comply with their R-squared, which are 0.97, 0.96, 0.98, and 0.81, respectively. Furthermore, 6.7%, 5.6%, and 5.2% water content average potential values are 5.6V, 6.2V, and 7.2V, respectively, which are inversely proportional. The proportionality between water content of soil and potential value reading proves the KZP has potential to detect the water leaks.

Influence of tap water stagnation on copper and iron concentration as a function of pH

The water at the consumer's tap may have a quality far removed from that obtained from the distribution service due to contamination by metallic trace elements. This is why this work is interested in studying the influence of the stagnation of tap water on the concentration of copper and iron. Thus, the levels of Cu and Fe in water with a composition similar to that of the public water supply of Niamey (Niger) in stagnation in four types of pipe were monitored. These are cast iron, galvanized steel, polyvinyl chloride (PVC) and polypropylene (PPR) pipes. The analyzes of the water samples were carried out by flame atomic absorption spectrometry. It appears from this study that all the pipes made up of these pipes and accessories release Cu and Fe into the water under the conditions of the experiment. Metal pipes, in particular the cast iron pipe, release these two metals much more than plastic pipes, in particular PVC. Thus, the new cast iron pipe releases exceptional maximum quantities of iron of the order of 1 to 1800 times the guideline value of 0.3 mg.L-1 after 4 hours to 90 days of water stagnation.

Planning for Clean Water Needs in ITP Main Building

Plumbing system planning is an important part of a building to meet clean water needs. This study aims to plan a plumbing system for clean water in the ITP main building. Meeting the needs of clean water is planned to use water sources from shallow wells that are pumped into the roof tank (roof tank) and flowed gravitationally to pump two. The results of the calculation of the average water requirements of office buildings are 53 liters / day. The capacity of the roof tank needed to accommodate clean water is 2,100 liters, using two roof tanks with a capacity of 1,050 liters each. Roof tanks are placed on top of towers as high as 7.15 m. The diameter of the clean water pipe needed is 20-50 mm. The pump power needed is 0.071 kw and for the second pump is 0.63 kw. The type of pipe planned for this clean water plambing system is Polyvinyl Chloride (PVC) pipe.

Experimental Study of RC Hollow Beams with Embedded PVC Pipes

This study investigated the behaviour of reinforced concrete (RC) hollow beams under incremental static loads. Polyvinyl Chloride (PVC) pipes were used to create longitudinal voids in hollow beams. The parameters studied included the size (25 mm, 50 mm and 75 mm diameter) and location (39 mm and 139 mm from beam soffit) of the PVC pipes in the beam. Nine specimens were tested under the four-point load test setup. The loads were progressively increased until the specimens failed. The specimens were analysed based on the failure modes, load-displacement responses and mechanical properties. The hollow beams gave a 2% to 36% lower strength than the solid beams. In terms of the strength per unit concrete, the hollow beams were less efficient than the solid beams. The efficiency ratio of hollow beams ranged from 0.67 to 1.0. For that, none of the proposed hollow beams was recommended.

Passive flow control of vortex-induced vibrations of a low mass ratio circular cylinder oscillating in two degrees-of-freedom

Offshore wind turbine towers are often placed vertically before installation at ports. At certain wind speeds, these towers are subject to vortex-induced vibrations and can lose up to a third of their fatigue live within a few days. So far, helical strakes have primarily been used in the upper part of the towers. These have so far proven to be not effective enough to suppress vortex-induced vibrations. The aim of this study was to develop a passive flow control method for offshore wind turbine towers and to experimentally investigate its efficiency.Experiments were performed in a circulating water tank to investigate using fin plates to suppress vortex-induced vibration of fully submerged flexible cylinders in flows at Reynolds numbers, referred to the cylinder diameter, between 1.4 × 104 and 8.0 × 104. The corresponding non-dimensional reduced velocities (normalized via the free stream velocity, the excitation frequency, and the diameter of the cylinder) were between 1.1 and 6.1. The cylinders’ of aspect ratio 18.8 had a mass ratio of 0.535. This mass ratio, referred to the mass of an oscillating cylinder normalized by the mass of displaced fluid, was below the critical mass ratio of 0.545. Each cylinder consisted of a polyvinyl chloride pipe mounted as a cantilever beam on a six degrees-of-freedom piezoelectric transducer. The top end of the cylinders was free to oscillate in the streamwise and lateral directions. An accelerometer was placed near their tops to measure accelerations and, via twofold integration, to retrieve top-end cylinder motions. A Laser Doppler Velocimetry system was employed to measure free stream velocities at the inlet of the water channel and wake velocities behind the cylinder. The wake velocities were used to calculate shedding vortex frequencies. Dynamic forces and displacements were also measured. Results demonstrated that fin plates attached to the cylinders mitigated their vibrations considerably. Optimized fin plate arrangements reduced amplitudes of streamwise and lateral vibration by 81 and 75%, respectively, and amplitudes of lateral forces acting on the cylinders by between 40 and 75%. Low uncertainty estimates of measured values substantiated the reliability of the results.

Quantitative analysis of smokeless powder particles in post-blast debris via gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV).

Forensic analysis of smokeless powder particles recovered from the debris of an improvised explosive device can provide information about the type of smokeless powder used and can aid investigation efforts. In this study, quantitative methods were used to yield information about the difference in the chemical composition of the particles pre‐ and post‐blast. The technique, gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV), was able to quantify nitroglycerin, 2,4‐dinitrotoluene, diphenylamine, ethyl centralite, and di‐n‐butyl phthalate in pre‐ and post‐blast smokeless powder particles using heptadecane as an internal standard. Post‐blast debris was obtained via controlled explosions with assistance from the Indiana State Police Bomb Squad. Two galvanized steel and two polyvinyl chloride pipe bombs were assembled. Two devices contained single‐base smokeless powder and two contained double‐base smokeless powder. 2,4‐dinitrotoluene and diphenylamine were successfully quantified in the single‐base smokeless powder post‐blast debris while nitroglycerin, diphenylamine, and ethyl centralite were successfully quantified in the double‐base smokeless powder post‐blast debris. Compounds were detected at concentrations as low as 9 μg of 2,4‐dinitrotoluene per mg, <3 μg of diphenylamine per mg, 131 μg of nitroglycerin per mg, and <3 μg of ethyl centralite per mg. Concentration changes between pre‐ and post‐blast smokeless powder particles were determined as well as microscopic differences between pre‐ and post‐blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives.

Leak before break fracture assessment of pressurized unplasticized PVC pipes with axial surface crack: Experimental and analytical analysis

This paper compares Failure Assessment Diagram-based and Stress Intensity Factor-based analytical approaches with experimental results for assessing leak before break in axial finite semi-elliptical cracked Polyvinyl Chloride pipes subjected to internal pressure. Surface crack length of 25, 40 and 60 mm and depth to thickness ratio of 0.25, 0.5 and 0.75 were investigated. Burst pressures are experimentally evaluated for all cracked and uncracked samples. Results illustrated that the Failure Assessment Diagram approach is more reliable than Stress Intensity Factor approach for fracture assessment of unplasticized PVC pipes.

Asphaltene or Polyvinylchloride Waste Blended with Cement to Produce a Sustainable Material Used in Nuclear Safety

The current research uses sustainable methods to preserve the environment, such as exploiting municipal or industrial waste that may harm the environment. The wreckage of polyvinyl chloride (PVC) pipes and asphaltene are used as additives to cement to improve its mechanical properties, while stabilizing the radioactive waste resulting from the peaceful uses of nuclear materials, or enhancing its radiation shielding efficiency. New composites of Portland cement with ground PVC or asphaltene up to 50% are investigated. Fast neutron removal cross-section (ƩR) and gamma shielding parameters, such as mass attenuation coefficient (MAC), half-value layer (HVL), effective atomic number (Zeff), and exposure build-up factor (EBF) at wide energy range and thickness, are determined. The compressive strength and apparent porosity of the examined composites are examined to test the durability of the prepared composites as stabilizers for radioactive waste. The obtained results show that the bulk density of hardened cementitious composites was slightly increased by increasing the additive amount of PVC or asphaltene. The compressive strength of cement composites reached more than 4.5 MP at 50 wt.% PVC and 8.8 MPa at 50 wt.% asphaltene. These values are significantly higher than those recommended by the US Nuclear Regulatory Commission (3.4 MPa). Additionally, the obtained results demonstrate that although the gamma MAC is slightly decreased by adding asphaltene or PVC, the neutron removal cross-section was highly increased, reaching 171% in the case of 50 wt.% asphaltene and 304% in the case of 50 wt.% PVC. We can conclude that cement composites with PVC or asphaltene have optimized radiation shielding properties and can stabilize radioactive waste.

Environmental life cycle assessment of different types of the municipal wastewater pipeline network

AbstractWith the onset of social life, humans have considered waste disposal as essential, and they have been able to repel it through brick and clay channels. Checking sewage pipes for energy consumption and a longer lifetime than other sewage system components is important. Climate change and exploitation of industrial resources have made environmental impacts, which are important factors in decision making. The purpose of this study was to introduce the most suitable type of sewage pipe considering environmental protection. Therefore, we applied the environmental life cycle assessment (LCA) method, using Sima Pro 8.2.3 software for the one‐kilometer length of concrete pipes (300 mm in diameter), Polyvinyl chloride (PVC), and polyethylene (PE) (315 mm in diameter). Also, the BEES method and sensitivity analysis were used to validate the results. The comparison between three types of municipal wastewater pipes indicated that PE pipes are a more environmentally friendly option than PVC, and concrete pipes in pipe recycling, reducing extraction from untapped resources, and inefficient extraction of resources. Electricity, diesel fuel, and sulfate resistance cement consumption for concrete production are the most pollution elements in the LCA of concrete pipes. Usage of PVC granular, sanitary landfill of PVC pipes, and using hydraulic drill in LCA of PVC pipes are the most elements of generating pollution. The usage of PE granules, PE pipes landfilling, hydraulic excavator, and electricity consumption in the LCA of the PE pipes are the greatest polluting parameters.

Phycoremediated N-fertilization approaches on reducing environmental impacts of agricultural nitrate leaching

Nitrate leaching is one of the prominent problems of extensive agriculture in attaining maximum yield. Excessive use of nitrogenous fertilizers leads to nitrate (NO3−) pollution in the groundwater and detrimental effects on the environment. In this study, we have phycoremediated the sewage wastewater and evaluated the impact of remediated wastewater on the extent of nitrate leaching in the field condition on the spinach crop. The experiment was set up in polyvinyl chloride (PVC) pipes of dimension 100 cm in length and 30 cm in diameter. The leachates were collected from the depth of 15, 30, 45, 60, and 90 cm to measure the nitrate leaching. The application of microalgal manure significantly reduced NO3− leaching compared to chemically fertilized treatment. The NO3− content in the collected leachate in the treatment T1 at the depth of 0–15 cm (5.03 mg/L), 15–30 cm (5.80 mg/L) and 30–45 cm (4.98 mg/L) was significantly lower than the treatment T5 at the depth of 0–15 cm (8.57 mg/L), 15–30 cm (7.97 mg/L) and 30–45 cm (8.16 mg/L). The reason behind less leaching of nitrate in the algae manure applied treatment was due to the fact, as most of the N fixed by the microalgae present in the form of complex compounds. The leaching could only occur after the mineralization of these compounds. In addition, ammonium content in spinach after harvest was also analysed. Similar to nitrate, the ammonium content was also lesser in phycoremediated manure treatment than chemical fertilizers. The cumulative ammonium content at the depth of 0–15, 15–30 and 30–45 cm in the treatment T1 (121.70 mg/kg) was significantly lower that the treatment T5 (136.43 mg/kg). Optimization methodology of sewage wastewater phycoremediation and its use as adapted N-fertilization presented in this study can be applicable as a policy guideline for sewage wastewater use for irrigation which reduce nitrate leaching and reduce the dependency on the environmentally harmful chemical fertilizers.

Nematodes of soft bottoms from the ‘Po’ol Tunich’ cave system, Quintana Roo, Mexico

ABSTRACT The Yucatán Peninsula is a vast karst platform that hosts superficial ecosystems such as sinkholes or underground cave systems. This study aims to give the first nematode species list for and explain their distribution at the Po´ol Tunich cave system. Samplings were carried out from September 2015 to February 2016, at five sampling sites along the cavern system. At each site, two sediment samples were collected with a polyvinylchloride pipe (PVC) corer; sediments were processed by decantation, and meiofauna was collected with a 45 µm sieve. Nematodes were picked manually, mounted on glass slides and identified. At three sites (1, 3 and 5), water temperature and electric conductivity were measured with HOBO data loggers. The nematode fauna was represented by six orders, nine families and 12 genera. Enoplida and Chromadorida have the highest number of species (three each), while Rhabditida and Plectida have two species each. There was only one species of Dorylaimida. Sites with the highest abundance were: 1 (25 organisms) and 2 (24 organisms), with Atrochromadora sp. as the most abundant species, followed by Ironus paludicola, Hoplolaimus tylenchiformis and Dichromadora sp., at five organisms each. The four types of nematode feeding were present, with a predominance of epistrate and deposit feeders, followed by chewers and then suction feeders, and this fact is an indicator of the food resources available in the cave. Our results reveal that nematodes are an important component in the cave fauna, and they exploit the resources available based in detritus. Further efforts are needed to understand the nematode communities associated with subterranean environments.

Impact of pipe material on the wall reaction coefficients and its application in the rehabilitation of water supply system of San Pedro Nexapa, State of Mexico

Abstract One of the major challenges faced by water companies around the world is the high level of chlorine losses in distribution networks. This paper presents an experimental study to examine chlorine loss in different types of pipe materials and select the ones with low chlorine demand for the rehabilitation of the water distribution network of San Pedro Nexapa, State of Mexico. The materials investigated include: polyvinyl chloride (PVC), galvanized steel (GS), polypropylene (PP) and high-density polyethylene (HDPE). A 24-h chlorine consumption study was performed in a simulated water distribution network to assess the impact of wall reaction coefficient on chlorine decay. Four sets of independent pipe loops of 50 mm in diameter and 12 m in length were used. Two different scenarios were considered based on different initial chlorine concentration (1.21 mg/L and 1.60 mg/L). Samples were collected at each loop at two-hour intervals and physicochemical analyses were conducted. Results from the experimental distribution network showed that the wall coefficient values for GS, HDPE, PP and PVC were 0.165 h−1, 0.059 h−1, 0.043 h−1 and 0.026 h−1, respectively. Experimental results showed that wall reaction coefficient values depend on initial chlorine concentration and the characteristics of pipe material. The rate of free chlorine decay was found to be faster in steel pipe and slower in the plastic pipes. Based on its having the lowest chlorine demand compared with the other pipes, PVC pipe would be selected to rehabilitate Nexapa water distribution network, State of Mexico. The wall coefficients from the experimental study were incorporated into EPANET through four simulation runs to predict chorine decay of San Pedro Nexapa water distribution network, State of Mexico. In the PVC and PP pipes higher residual chlorine concentrations were observed that ranged from 0.30 to 0.90 mg/L and 0.50 to 0.95 mg/L, respectively. This study is important for utilities to operate their system effectively and protect public health.

Use of a threaded-coupled femoral extraction device allows for higher extraction force when compared to loop or vice grip devices; A potted stem analysis

BackgroundExtraction of a well-fixed femoral stem during revision total hip arthroplasty presents a technical challenge to the operating surgeon. The option of several stem designs during implantation necessitates the availability of extraction tools to be utilised intra-operatively. This study aims to compare the amount of axial force generated from using a threaded-coupled extraction device, loop extraction device, and vice-grip universal extraction set on a potted total hip arthroplasty stem construct. MethodsA size 7 Stryker Accolade® II femoral stem (Stryker, Mahwah, NJ) was potted within a 5.20 cm inner diameter polyvinyl chloride pipe using a potting medium with tensile strength and lap shear of 1000psi. This construct was coupled to a material testing system whose force transducer was calibrated to a recording speed of 1000 frames per second. The extractors were coupled to the potted stem, and a force of 1.32 J was applied ten times sequentially to each construct. Force was recorded in Newtons. ResultsThe maximum average force for the threaded, loop, and Shukla extractors was 111.46 ± 1.77 N, 90.22 ± 0.87 N, and 64.70 ± 9.03 N (p < 0.01). Loss of coupling was not experienced with any extractor. ConclusionWithin our study, the forces observed per constant load when utilising a threaded-coupled extraction device that attaches to the shoulder of the implant were significantly higher than those seen when using an extraction device that couples to the neck of the femoral stem.

Investigation of Ice Specimens Reinforced in the Middle Section with Thin-Walled Pipes Made of Polymeric Materials

The paper is devoted to the construction of road crossings on the territory of the Arctic shelf and the Extreme North (Far North), as well as on the Siberian and Far Eastern rivers in winter. That is going to contribute to reducing logistic costs from cargo shipping down the ice surface significantly. In this research, the authors examine ice-based composites, where thin-walled polyvinyl chloride pipes are placed in the middle of the sample cross-section as a reinforcer. Two types of pipes were tested: vent white and orange sewer (drain) ones. While doing several series of model experiments, the researchers find out that the load-bearing capacity of ice samples reinforced with these pipes show very much the same results. So it was decided to combine the averaged model experiments with these pipes into one concluding result. The mechanical characteristics of ice were figured out by crushing samples of ice prisms that are 60 cm long, with a cross-section size of 15x15 cm. The aim of the paper is to define the influence of thin-walled polyvinylchloride pipes on the plastic properties and load-bearing capacity of ice samples when they are being reinforced. The test results prove that when reinforced with a pipe, it is destructed more gradually, and the deformations before the destruction have greater values. However, the thin-walled SN2 and SN4 pipes add nothing to increasing load-bearing capacity, unlike the SN8 sample, which increased the load-bearing capacity by about 10%. Therefore, the reinforced mid-section of ice samples with thin-walled PVC pipes marginally increased the plasticity of the samples, without the marked increase in the load-bearing capacity.

임계점 부근의 이산화탄소-메탄 혼합물의 관내 응축 열전달 특성 연구

The condensation heat transfer coefficient and pressure drop for pure CO₂ and CO₂+CH₄ mixture were investigated under the near-critical condition, which simulates the CO₂ transporting conditions under Carbon Capture and Storage (CCS) process. The experimental facility consisted of a test section, heat exchangers, mass flow meters, temperature sensors, a magnetic gear pump, and a differential pressure transducer. The test section made with a copper tube was assembled with Polyvinyl Chloride (PVC) pipe to form a double tube. The condensation temperature and mole fraction of CH₄ in the CO₂ mixture ranged from 20℃ to 30℃, and 1% to 5%, respectively. The mass flux was changed from 500, 600, and 700 kgm-2s-1. The two-phase flow pattern under the set conditions was estimated to be the annular flow. When the mole fraction of methane in the mixture increased from 1% to 5% at 20℃ of condensation temperature, the average condensation heat transfer coefficients and the pressure drop for CO₂+CH₄ decreased from 4.97% to 19.9%, and 30.0% to 54.5%, respectively, compared to those for pure CO₂