Polyvinyl Chloride Pipe Research Articles

Effects of stocking density and shelter on the behavior, growth, and survival of Stichopus cf. horrens juveniles

Stichopus cf. horrens is an emerging sea cucumber species in tropical aquaculture. However, stocking density must be optimized. This study investigated the effects of stocking density (278 ind. m−2, 556 ind. m−2, and 1111 ind. m−2) and the presence or absence of polyvinyl chloride (PVC) pipes as shelters on the growth performance and survival of juveniles (0.4 to 1.0 cm) in the field over 30 days. The activity pattern, sheltering behavior, and aggregation density of juveniles (1.5 to 2.0 cm) at different stocking densities (144 ind. m−2, 289 ind. m−2, and 578 ind. m−2) were further evaluated in the laboratory for 15 days. Results revealed negative density-dependent effects on the absolute growth rate (AGR) and the coefficient of variation in length among the juveniles. The presence of PVC pipes did not significantly improve AGR of juveniles in all density treatments by day 30. However, survival rates were higher in sheltered treatments compared to the non-sheltered. During inactive hours, aggregations of juveniles were observed on the undersides of the PVC pipes, with high-density aggregations prevalent only at medium and high stocking densities, but not at low stocking densities. The direct physical contact during these aggregations likely exacerbated the effects of crowding and increased the risk of exposure to the cytotoxic chemicals produced by conspecifics. Designing shelter models that reduce the probability of encounter during shelter-seeking, while enhancing epiphytic growth and grazing efficiency, is crucial for mitigating the negative effects of density on this high-value sea cucumber species.

Towards more realistic stochastic modelling of leakage in water distribution systems

ABSTRACT A new stochastic model is developed to predict leak types and sizes in water distribution systems. By linking records of actual failures in water networks with new tools for stochastic modelling, the study provides more accurate estimates of network leakage behaviour. District metered areas (DMAs) have been adopted internationally as best practice for monitoring and controlling leakage, with the infrastructure leakage index (ILI) as the main performance indicator. The leakage exponent (N1), which quantifies the relationship between leakage rate and pressure, is a key parameter in describing DMA leakage behaviour. After analysing thousands of stochastic networks for different combinations of pipe material and ILI, the study found that different pipe materials have distinct leakage exponent distributions. Iron and asbestos cement (AC) pipes display N1 values close to 0.5, polyvinyl chloride (PVC) pipes have the highest N1 values, and polyethylene (PE) lies between PVC and iron/AC. The study further showed that current guidelines linking ILI to N1 for different pipe materials depart substantially from the observed results, indicating that these guidelines may need to be updated. The study provides a tool for more realistic modelling of leakage that offers valuable insights into the behaviour of leakage in different pipe materials.

Toward production zonal flow allocation using novel completion tracer dosing line and diffuser: Prototype laboratory flow loop experiments and computational fluid dynamics studies

Complex completion schemes with inflow control valves (ICVs) in multi-lateral wells are now the industry standard for modern fields. Understanding the production contributions from different production zones/laterals is of great importance in optimizing the zonal flow rates to prolong the field lifetimes, reduce water cuts and the associated costs, and achieve production targets. Furthermore, the improved operational efficiency can reduce the producers’ energy usages and carbon footprints for a more sustainable operation. For the past decade, inflow tracer technology based on embedding tracers in degradable polymer matrices, which are then placed in downhole completion zones at initial installation, has been used in understanding production zonal flow contributions in field demonstrations as well as in commercial projects. However, the current technology based on degradable polymers has the following limitations: (1) there are limited lifetimes for the degradable polymer matrices that will lose their functionality past their expiration dates, and (2) the tracers are released from the polymer matrices at a constant rate; so in order to create a transient for tracer flowback measurements the wells need to be shut-in for a period of time which will interfere with normal production and possibly, with the long-term productivity of the well. Here, we introduce an alternative approach for deploying inflow tracers that has no such limitations mentioned above. Specifically, we propose the installation of passive chemical tracer dosing lines connected to diffuser chambers at the annular regions downhole during completion. Pulses of tracers can be injected into the different production zones and monitored for their flowback characteristics on-demand. The passive tracer dosing lines and diffusers only require minimum upfront investments and have no limitations of lifetime compared to the degradable polymer matrices. Furthermore, the injection of tracer pulses into the annulus near production zones creates appropriate transient responses for their flowback measurements, which do not require well shut-in and will not affect normal production.Laboratory flow loop experiments and computational fluid dynamics (CFD) studies were performed to demonstrate the proposed methodology and to understand the underlying physics. Half-scale and quarter-scale flow loops made of transparent polyvinyl chloride (PVC) pipes that resemble annular regions near the ICVs were constructed with tracer dosing lines and diffusers attached within. Colored dyes were injected into the flow loops to visualize their flush out and flowback behaviors. In CFD studies, a two-step approach was used with first solving for the turbulent fluid flow profiles, and then solving for the tracer convection diffusion behaviors in the turbulent fields. The CFD model parameters were carefully matched with flow loop experiments to predict the possible real field responses. With appropriate diffuser design, we can achieve desirable zonal flow-rate-dependent tracer flowback responses with reasonable sampling times and injected tracer quantities.

Biostability assessment of ultrapure water piping materials in the semiconductor industry and their susceptibility to Ralstonia growth

The pipes used for ultrapure water (UPW) distribution are constructed using high-quality materials to ensure purity. However, there remains a risk of contamination based on the pipe type. This study is the first to comprehensively evaluate the biological implications of various UPW pipe materials used in the semiconductor industry. The results showed that Polyvinylidene fluoride (PVDF) exhibited lower organic carbon leaching (0.08 mg/L) and a reduced biomass formation potential (BFP) (approximately 5 × 105 cells/cm2) compared to chlorinated polyvinyl chloride (CPVC) pipes. In particular, Ralstonia, an oligotrophic bacterium commonly found in UPW systems, formed a significant biofilm on pipe surfaces, notably in stainless steel (SUS) and CPVC pipes. Furthermore, particle contamination, a critical concern in semiconductor manufacturing, was investigated, focusing on potential contamination sources generated by pipe leaching and the presence of bacteria. The bacterial composition of the selected UPW was investigated, revealing Herbaspirillum, a nitrogen-fixing bacterium, as the dominant species, account for 66.15 %. Notably, the composition of the feedwater was different from that of the UPW. This study also highlights the limitations of culture-based methods, particularly in detecting bacteria under oligotrophic conditions, which are often unculturable. Flow cytometry (FCM) shows promise for the quick detection of bacterial contamination by providing total cell counts. Moreover, cytometric fingerprinting analysis revealed phenotypic differences between the communities. Nevertheless, further development of a simplified and widely applicable cell counting protocol is required for its effective integration into UPW production.

Low-temperature dechlorination of polyvinyl chloride (PVC) for production of H2 and carbon materials using liquid metal catalysts.

Polyvinyl chloride (PVC) is ubiquitous in everyday life; however, it is not recycled because it degrades uncontrollably into toxic products above 250°C. Therefore, it is of interest to controllably dechlorinate PVC at mild temperatures to generate narrowly distributed carbon materials. We present a catalytic route to dechlorinate PVC (~90% reduction of Cl content) at mild temperature (200°C) to produce gas H2 (with negligible coproduction of corrosive gas HCl) and carbon materials using Ga as a liquid metal (LM) catalyst. A LM was used to promote intimate contact between PVC and the catalytic sites. During dechlorination of PVC, Cl is sequestrated in the carbonaceous solid product. Later, chlorine is easily removed with an acetone wash at room temperature. The Ga LM catalyst is reusable, outperforms a traditional supported metal catalyst, and successfully converts (untreated) discarded PVC pipe.

Experimental Study Employing EMI-based Piezoelectric Diaphragms to Detect Water Leakages in PVC Pipes

Considering the increased demand for using natural resources sustainably, water is an ultra-valuable resource to be preserved. Notwithstanding, Polyvinyl Chloride (PVC) pipes, which are mainly used in complex building water distribution systems, are still in use and present a considerable rate of water loss. Unfortunately, the recently developed Structural Health Monitoring (SHM) has not deeply covered leaks in those pipes. To fill this gap, this approach proposes an experimental study to assess the feasibility of using Lead Zirconate Titanate (PZT) diaphragms to detect water leaks in these structures. Experimental tests were conducted by attaching one PZT diaphragm to a mini-scale water distribution system, where the leakage scenarios were simulated by opening taps. To attest to the effectiveness of the methodology, it calculated statistical metrics between the baseline (without leaks) and unknown conditions. The experimental results are promising and may be extrapolated to detect water losses in a full-scale water-distributing system.

Development and characterization of log periodic feedline based filter for water leakage detection in size invariant PVC pipes

In this proposed work, water leakage detection in Polyvinyl chloride (PVC) pipes has been investigated using a ring filter connected to log-periodic feedlines (LPF). The proposed filter has a well-structured ring design to adjust the PVC pipes and operates between 0.3 GHz & 0.7 GHz. Using a signal generator & analyzer, attenuation measurements are obtained to analyze the impact of water leakage. PVC pipes with varying diameters (3 inches, 2 inches, 1.5 inches, & 1 inch) are connected with water stoppers to control the water flow during experiments. The leak is contained within a plastic tub to make measurements easier. Results show a good connection between attenuation & water level for all pipe diameters, supporting the LPF-based ring filter’s effectiveness as a leakage detector. An analogous circuit model is created to evaluate the filter’s performance further. At the same time, the resonant parameters, such as Q-factors & resonant frequencies, are retrieved from S21 magnitude measurements in the operating frequency range. The proposed methodology is shown to be accurate & reliable, offering significant potential for water leakage detection in PVC pipe systems. By accurately detecting water leakage, this technology enables prompt repairs, reducing water loss & associated costs, enhancing water infrastructure, and promoting sustainable water management.

Design and application of a testing device for solar reflective materials

Using white polyvinyl chloride pipes, gray polyvinyl chloride pipes, natural rubber foam sheets, and nylon 6 as experimental materials, this article designed a sandwich structure solar reflective material testing device. By testing the thermal conductivity of various materials and the thermal conductivity of the composite materials in the device and conducting thermal insulation verification experiments on the solar reflective material testing device, it was found that the overall thermal conductivity of the device was small and the internal temperature of the device was less affected by the external environmental temperature. The results indicated that the solar reflective material testing device has good insulation performance.

Development and Validation of a Low-Cost Drilling Model.

Background: Simulation models enable learners to have repeated practise at their own time, to master the psycho-motor and sensory acuity aspects of surgery and build their confidence in the procedure. The study aims to develop and evaluate the feasibility of a low-cost drilling model to train surgeons in the drilling task. The model targets three aspects of drilling - (1) Reduce plunge depth, (2) Ability to differentiate between bone and medullary canal and (3) Increase accuracy drilling in various angles. Methods: This cross-sectional study was conducted after obtaining ethics approval. We invited Consultants in the field of Orthopaedic or Hand Surgery to form the 'expert' group, and the 'novice' group consisted of participants who had no prior experience in bone drilling. We developed a drilling simulator model made from a polyvinyl chloride (PVC) pipe filled with liquid silicone. This model cost less than US$5. An electric Bosch drill (model GBM 10 RE) with a 1.4 mm K-wire 10cm in length (6.5 cm outside the drill) was used for drilling. The main outcomes of the study were time taken for drilling, plunge depth, ability to penetrate the far cortex and accuracy. Results: Thirty-one participants were recruited into the study, of which 15 were experts and 16 were novices. The experts performed significantly better for plunge depth (t=-3.65, p=0.0003) and accuracy (t=-2.07, p=0.04). The experts required 20% less time to complete the drilling tasks, but it was not statistically significant (t=-0.79, p=0.43). Conclusions: The low-cost drilling model could be useful in training Residents in the drilling task. It will allow Residents to practise independently at their own time and assess their own performance.

Continuous production and recirculation of plasma‐activated water bubbles under different flow regimes for mixed‐species bacterial biofilm inactivation inside pipelines

AbstractBiofilm formation in broiler drinking water systems is a public health concern. Bacterial detachment from the pipes into the drinking water subsequently increases the risk of waterborne transmission and has detrimental effects on animal and human health. The study evaluated the antimicrobial effectiveness of plasma‐activated water bubbles (PAWBs) recirculated under different flow regimes against the mixed‐species biofilms of Salmonella Typhimurium ATCC13311 and Aeromonas australiensis 03‐09 grown on the inner surfaces of polyvinyl chloride (PVC) pipes. A benchtop pipeline model representing broiler drinker lines was developed to compare the biofilm inactivation efficacy of PAWB recirculated at different flow rates, corresponding to Reynold's number of 1000, 2500, and 4000. The synergistic mechanical and oxidative recirculation using PAWB resulted in a higher biofilm inactivation from the pipe walls as compared to recirculation using distilled water alone. Apart from the flow regimes, various parameters including the volume of PAWB circulated, the concentration of the major plasma reactive species, and treatment time affected the susceptibility of the mixed‐species biofilms to PAWB treatment. Under all tested conditions, the bacterial cells were below the detection limit of 1 log CFU/mL in water after PAWB treatments. A better understanding of the hydrodynamic variations prevalent in the drinking water system is important for designing an effective disinfection protocol using PAWB. The results obtained from the study provide important information on the use of PAWB for biofilm control strategies.

Tensioned flexible riser vibrations under wave excitation, an investigation on the scale effect

In order to study the scale effect in wave-structure interactions and the role that structure-related parameters (tension T or bending stiffness EI) plays, riser model tests under regular waves were conducted using the model with multiple geometric scales (1:15, 1:12 and 1:9) in a wave basin. The riser model used is a novel structural design combing the outer polyvinyl chloride pipe with the core steel rod which could be simplified as a cantilever beam. Different initial tension T acting on the riser are tested by adjusting the slotted weight. The results show that the amplitude varies in a cubic fashion with the distance from the fixed end. In addition, the influence of the wave period and top tension T on the amplitude are investigated, which ultimately leads to a dimensionless number π1 = KCd·TL2/EI where KC is the classical Keulegan–Carpenter number (KC), EI shows the bending stiffness of the riser model and L gives the pipe length. With the KC number revised to take the distance from the fixed end into the calculation, this parameter provides a good measure in estimating the amplitudes of the riser vibrations induced by the waves.

Application of a hydrophobic coating to a pressurized pipe and its effect on energy losses and fluid flow profile

The use of additives, generally called DRAs (Drag Reducing Additives), has been proposed to re-duce the energy consumption in pressurized pipes. Although many research works have been conducted to analyze the effect of these additives, less attention have been devoted to the application of coatings to the pipe wall. This paper demonstrates that the application of a hydrophobic coating to the pipe can lead to a head loss reduction for a transition flow regime with moderate Reynolds number values (Re). For this purpose, an experiment was conducted to compare the performance of both coated and uncoated pipes by measuring the head losses and assessing the Drag Reduction Percentage (%DR) and the pipe friction factor (f). This was done for two Polyvinylchloride (PVC) pipes with different nominal diameters (PVC90 and PVC63). In addition, the flow velocity distribution was also measured in all these tests. The %DR decreased as the Re values increased, with the reduction being notably less pronounced for higher Re values. This could be explained by the fact that a partial slip condition is induced by the hydrophobic product. Its effect is significant for a transition regime where the effect of viscosity is important, but it becomes negligible for increasing levels of turbulence. No significant differences were observed in the flow distribution between coated and uncoated pipes, which seems to indicate that the velocity change could be limited to the near-wall viscous sublayer. The results of this work open an important research line aimed at reducing energy costs and the carbon footprint in pipe fluid distribution systems.

Selective recovery of palladium from wastewater by modified PVC waste pipe

Green, efficient, and cost effective methods of recycling palladium (Pd) from wastewater have attracted increasing attention. In the present study, polyvinyl chloride (PVC) was utilized as a backbone for N-(3-aminopropyl)-imidazole to graft onto and yield an adsorbent suited for selective Pd recovery from wastewater by chlorine coordination. Batch experiments showed that the self-synthesized adsorbent had a Pd(II) adsorption rate of >99% at pH 1.0–3.0 and >93% in 4 min. The selectivity of the adsorbent in a complex mixed system containing high concentrations of typical base metals (CCu(II):CZn(II):CPd(II) = 66:33:1) was investigated, and the adsorbent demonstrated much higher selectivity for Pd (97.59%) than for Cu (0.52%) and Zn (2.96%). The adsorbent can also be reused as the adsorption rate remained above 99% after five cycles. Furthermore, waste PVC pipes also could be used as the synthetic raw material. The adsorbent demonstrated a high adsorption rate even when synthesized from discarded PVC pipes and the adsorption rate reached over 93% in 2 h and reached 95.15% at equilibrium in 4 h. Scanning electron microscopy and energy-dispersive spectrometry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to analyze the adsorption mechanism, which was attributed to electrostatic interaction and intermolecular interaction. The self-synthesized adsorbent is potentially applicable to the green recovery of Pd from wastewater owing to its high adsorption rate and selectivity.

Thermal Performance of Earth Air Heat Exchanger for Geothermal Energy Application in Hot Climate using CFD Simulation

The Ground Air Heat Exchanger (GAHE) is a sustainable, environment friendly, and efficient device that can be used for both heating and cooling applications. Careful design of GAHE enables efficient exploit of the earth interior energy. The design of a GAHE relies on the constant temperature of the earth interior which allows consistent and reliable source of geothermal energy. By harnessing this renewable energy, a sustainable solution for heating and cooling needs is attained while minimizing the impact on environment. In this study, the performance of GAHE was examined using ANSYS Fluent 19 R1 and SOLID WORK 16.0 software. The efficiency and Coefficient of Performance (COP) of the ETHE have been investigated. The effect of air flow rate and operation conditions on the outlet air temperature have been studied. GAHE is made of Polyvinyl Chloride (PVC) pipe of 0.1 m diameter, 0.005 m thickness and 18 m horizontal length. Computer simulations were carried out for five different air velocities (1, 2, 3, 4, and 5 m/s) at various operation conditions. Results show that the 18 m pipe length is adequate to attain useful air outlet temperature giving COP values between 0.5 and 1.3. The length of the horizontal part of GAHE can be further increased for air velocities between 3 and 5 m/s. Comparison between the results obtained by the CFD model and experimental work demonstrated that the CFD model is capable of producing results with acceptable accuracy. This suggests that the CFD software can accurately model the performance of the GAHE under different operation conditions. Increasing the length of the horizontal part of the GAHE can improve its COP when higher air velocities are used.

Flow resistance of phloem sieve plates revisited using an experimental model

Flow resistance of phloem sieve plates revisited using an experimental model

High Precision Ultrasonic Testing Method for Density of Engineering Plastics

The density of engineering plastics is a key parameter for ensuring their safety and reliability. In order to achieve rapid and high-precision on-site detection, a method based on the acoustic pressure reflection coefficient is proposed. First, finite element simulation analysis was conducted to obtain the acoustic field distribution during ultrasound propagation under water immersion conditions. The correlation between interface echo intensity and material density was determined. Optimal detection parameters were designed to reduce measurement errors caused by beam overlap and diffusion attenuation. A water immersion ultrasonic experimental system was constructed, and the measurement accuracy of the method was tested using chlorinated polyvinyl chloride pipes. The results show that, compared to the measurement results of the Archimedean drainage method, the maximum error of ultrasonic measurements does not exceed 1.7%, and the overall variance is less than 1.2%. The measurement accuracy of this method is compared with the regression results of different machine learning models. It is demonstrated that, compared to regression methods based on variable correlation, this method retains the advantages of high efficiency and low cost in ultrasonic density measurement, while achieving higher measurement accuracy. Additionally, it does not require a dataset for training support, making it promising and valuable for practical applications.

Performance evaluation of looped tube thermoacoustic power generator using cyclic analysis

This paper focuses on the numerical and experimental investigation of the small-scale power generator. The travelling wave thermoacoustic power generator is numerically analyzed and experimentally tested. The cyclic analysis is used to carry out numerical analysis of the power generator. The system is operated on atmospheric pressure, which allows the manufacturing of an acoustic feedback loop using Polyvinyl chloride piping. The acoustic power generated inside the generator is harnessed by the low-cost linear alternator, i.e., loudspeaker. The effect of regenerator wire mesh on performance of the power generator is numerically analyzed and validated experimentally. The numerical analysis identifies the temperature variation, pressure fluctuation, volume flow rate inside the system, and acoustic power distribution. The maximum electric power experimentally generated by the small-scale power generator is around 45 W with overall efficiency 8.30%. The alternator generates the maximum electric power at the optimum location, i.e. 2.30 m away from the engine core.

Development and Performance Evaluation of a Vacuum Drum Based Water Pumping System

A vacuum drum based water pumping system (VDBWPS) is a cost effective system for lifting and carrying water from a nearby flowing canal/nallah as well as from standing water of farm pond/open well. The main component of the developed system includes of a mild steel (MS) drum, polyvinyl chloride (PVC) pipe, jointer, elbow joint, T-joint, L-joint, regulator valve, and foot valve. In this system water can be filled manually or via other devices, such as a solar pump or a treadle pump. The drum's capacity is nearly 80% filled, and the remaining 20% is kept empty. A continuous supply is created by closing both air release valves and opening the discharge valve. More is the vacuum, better will be the pumping. The testing of vacuum drum based water pumping system was evaluated at different suction lift and carrying horizontal distances, both affecting the discharge. The result show that the water pumping system gave a discharge 2.22 to 2.40 litre per minute (lpm) at a constant suction lift of 0.92 meter (m) and varying distances 0 to 12 m. it was also found that the discharge increase with the distance having peak discharge at 6 m i.e. 3.75 lpm and afterwards it decreases gradually as the carrying length increases. The vacuum drum based water pumping system can give a discharge of 5400 litre per day (lpd) at 0.92 m of suction lift and carrying horizontal distance of 6 m. The cost of operation of vacuum drum based water pumping system was 352.41 ₹/day. It has always been a demand that the "technology should be technically feasible, economically viable and socially acceptable".

Construction and Comparison of the Efficiency of Water Heating Systems using low Cost Solar Collectors

This work describes the manufacture of two solar water heating (SWH) systems, one using polyvinyl chloride (PVC) pipes and the other using PVC plates, both with approximately the same area of collecting solar thermal energy. The aim is to analyze their efficiencies and discuss physical concepts and their practical applications. Both SWH collectors were placed side by side under the sun, such that they were submitted to the same climatic conditions. This work also draws attention to the importance of using solar radiation1 as an alternative and sustainable source of energy for water heating.

Corroded iron pipe inhibits microbial-mediated Mn(II) oxidation and MnOx accumulation compared to PVC pipe

MnOx deposits in distribution pipes can cause severe discoloration problems in drinking water. However, the impact of pipe materials on Mn(II) oxidation and MnOx accumulation remains unclear. This study investigated microbial-mediated Mn(II) oxidation and deposit formation through 300-day pipe loop experiments with corroded galvanized steel pipes (DN100) and new polyvinyl chloride (PVC) pipes (DN100). The results showed that influent Mn(II) was entirely oxidized within 48 h in the PVC pipes with biofilms in the absence of chlorine, while most influent Mn(II) remained unoxidized in the iron pipes. Dissolved oxygen (DO) monitoring showed that the DO in the PVC pipes was consistently higher than 8.0 mg/L, but that in the iron pipes dropped to 6.5 mg/L. Microbial analysis revealed that the abundance of potential Mn(II)-oxidizing bacteria in the low-DO iron pipes was less than that in the PVC pipes. Analysis of the Mn(II) concentration dynamics in different pipes revealed that the early Mn(II) disappearance in the iron pipes was contributed mainly to Mn(II) adsorption by iron corrosion products rather than microbial Mn(II) oxidation. When aeration was performed to increase the DO concentration to 8.0 mg/L in the iron pipes, complete Mn(II) oxidation occurred. This study provides insights into Mn(II) transformation in different pipes and highlights the critical role of DO in microbial Mn(II) oxidation in drinking water pipes.