Complibot: A compliant external pipe climbing robot

Analytical modeling for rapid design of bistable buckled beams

Effect of PVC and iron materials on Mn(II) deposition in drinking water distribution systems

Most of the underground sewer infrastructure in United States uses Polyvinyl Chloride (PVC) pipes to transport toxic fluids. Cracks in underground PVC pipes are a major cause of effluent discharge in underground sewer systems. Released effluents not only pose risk to the environment, but are also a threat to public health. As current industry standard, utility operators use a closed circuit Television (CCTV) camera mounted crawler to pass through the pipes, and record video to classify condition of the piping network. CCTV based systems are expensive and crew-hour intensive. Recently developed acoustic based pipeline inspection systems are being adopted by the utility operators. These systems, however, do not detect presence of cracks in pipes. This paper reports results of a study to monitor presence of cracks in PVC pipes using acoustic signals. The collected data from extensive laboratory trials is processed using machine learning algorithms to classify the difference between a clean and cracked pipe samples. We use Decision Tree, K-nearest neighbors (KNN), and Naive Bayes (NB) algorithms. The DT and KNN algorithm scores show the highest convergence between acoustic samples from a cracked pipe at frequencies greater than 3.0 kHz. The paper also lays out precision scores obtained from using machine learning algorithms on acoustic data from clean and cracked pipe samples.

A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis--gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensoryGC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GC peaks were produced as reaction products from leaching of primer in water and white or grey PVC pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified.

An Internet of Things (IoT) node-based nonintrusive, resilient liquid flow transmitter has been developed using a circular interdigital capacitor (IDC) as a primary sensor. A section of polyvinyl chloride (PVC) pipe is cut and a silicon tube of lesser diameter (compared with PVC pipe) is attached with the PVC pipe. A circular IDC is installed on the silicon tube and is used to convert the volumetric flow rate into corresponding capacitance. The change in capacitance with respect to the flow rate is nonlinear. Modified De Sauty bridge circuit is connected with the developed flow sensor to get the electrical output. To linearize the bridge output, three different linearization techniques, i.e., linear least square (LLS), genetic algorithm (GA), and artificial neural network (ANN) have been used and their statistical analysis is reported in this article. The best suited linearization technique (ANN) for the proposed sensor from the simulated result has been used in hardware implementation. This article proposes the IDC sensor access scheme design based on the IoT node and the transmission of the standard voltage signal 1–5 V using IoT node. The transmitted voltage and the received voltage have the same characteristic under the percentage error of ±0.5% of transmitted voltage. It has 0.286-pF resolution for measurement of liquid flow rate from 0 to 2000 litre per hour (LPH). This article highlights the theoretical analysis of the developed sensor to elucidate its working with maximum clarity. This sensor has been tested and its characteristics are thoroughly studied in the research workshop. Experimental results have proved that the wireless flow transmitter obeys linear characteristics and tuned well with theoretical equations based on the working principle. In addition, the proposed flow measurement is nonintrusive in nature as the circular IDC does not come in contact with the liquid flow, hence, increases the life span of the sensor.

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

Equilibrium sorption test, microscopic visualization test, and pipe-bottle permeation test were conducted to study the permeation of various organic solvents through polyvinyl chloride (PVC) and polyethylene (PE) pipes. Five PVC pipes from different manufacturers were used and all five pipes gave similar sorption results of trichloroethylene and toluene using the equilibrium sorption test. Sorption was rapid and reached equilibrium within 7-11 days. When different types of gasoline was used, PVC pipes sorbed less than 1.5% of gasoline after 100 days indicating the PVC can resist permeation of gasoline. It was noted that PVC pipes sorbed more premium gasoline than regular- and 10% ethanol gasoline about 0.85% gain in weight after 90 days. The visualization test confirmed the permeation of the premium gasoline where a moving front of 0.3 mm was observed at 120 days while there was no moving front detected in regular- and 10% ethanol gasoline. The results suggested that percent gain in weight of gasoline may be directly proportional to concentration of BTEX (benzene, toluene, ethylbenzene, xylene) in gasoline. In the presence of a solvent such as TCE or toluene, permeation of gasoline through PVC pipes may be enhanced. For PE pipe exposed to pure gasoline and aqueous solution saturated with gasoline, breakthrough of BTEX compounds occurred after 7 and 10 days of exposure. Concentration of individual BTEX compounds in pipe water at stationary state of permeation was over their MCL for both PE pipe exposed to gasoline and aqueous solution saturated with gasoline. Diffusion coefficients were strongly dependent on the concentration of individual BTEX compounds at the outer surface of the pipe wall

Removal of a Long PVC Pipe Strangulated in the Penis by Hot‐Melt Method

The leaching of organotin (OT) heat stabilizers from polyvinyl chloride (PVC) pipes used in residential drinking water systems may affect the quality of drinking water. These OTs, principally mono- and di-substituted species of butyltins and methyltins, are a potential health concern because they belong to a broad class of compounds that may be immune, nervous, and reproductive system toxicants. In this article, we develop probability distributions of U.S. population exposures to mixtures of OTs encountered in drinking water transported by PVC pipes. We employed a family of mathematical models to estimate OT leaching rates from PVC pipe as a function of both surface area and time. We then integrated the distribution of estimated leaching rates into an exposure model that estimated the probability distribution of OT concentrations in tap waters and the resulting potential human OT exposures via tap water consumption. Our study results suggest that human OT exposures through tap water consumption are likely to be considerably lower than the World Health Organization (WHO) "safe" long-term concentration in drinking water (150 microg/L) for dibutyltin (DBT)--the most toxic of the OT considered in this article. The 90th percentile average daily dose (ADD) estimate of 0.034 +/- 2.92 x 10(-4)microg/kg day is approximately 120 times lower than the WHO-based ADD for DBT (4.2 microg/kg day).

In this paper, we propose a novel gradient index metamaterial lens to focus elastic wave energy in polymer pipes. We investigate multi-mode focusing of guided ultrasonic waves in a poly-vinyl chloride (PVC) pipe by designing and integrating an embedded gradient index (GRIN) lens within the pipe wall. The metamaterial lens is composed of equally spaced cylindrical brass inserts embedded into the pipe wall. All the inserts are of same height which is equal to the half-thickness of the pipe. Insert diameters are varied in circumferential direction to realize hyperbolic secant distribution of refractive index around the circumference of pipe. We explore focusing of three pipe wave modes commonly used for guided wave inspection of pipelines namely, L(0,2), L(0,1) and T(0,1), using a single lens design. We further verify the lens performance through numerical simulations estimating the amplification of wave energy in focal regions of the GRIN lens for these three modes. We also estimate attenuation of guided waves propagating in PVC pipe through experimental measurements.

Pipes are mainly used in waste, drain and vent systems as well as transporting various liquids that might be corrosive, flammable, explosives, volatile, reactive, or sometimes hazardous to human health. Though pipes are used at the underground or above ground, all of them are exposed to vibration because of external factors. In this study, we focused on topology optimization of steel and PVC (Polyvinyl Chloride) pipes to get lighter ones which will lead to using less material during manufacturing, less CO2 emission while transporting them to usage areas by vehicles and easier assembling process. Firstly, new lightweight pipe designs were modeled, and then these novel pipe designs with lattice wall thickness were analyzed by using Ansys finite element program in clamped-free, hinged-hinged, and clamped-clamped boundary conditions to obtain the natural frequencies, mode shapes, and displacement values. Moreover, obtained finite element results for steel and PVC pipes were compared with analytical results calculated by using the equation to check and compare with the finite element results. Finite element results were found similar to analytical results at an acceptable level. The results show that lightweight pipes have similar natural frequency values to the commonly used pipe which has fully solid wall thickness and some significant results about displacement values were attained. Lastly, the effect of pipe material on vibration behaviors of pipes was investigated in depth.

Studies on vinyl chloride migrating into drinking water from polyvinyl chloride pipe and reaction between vinyl chloride and chlorine

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.

Problems due to the increase in agricultural land use change can be solved by hydroponic system applications. Many hydroponic studies have been conducted in several countries while their applications in Indonesia requires modification and adjustment. This research was conducted to design and construct a hydroponic system with semi-continuous and continuous nutrition systems. The hydroponic system which was used adapts the ebb and flow system, and the nutrient film technique (NFT). This hydroponic system was made from polyvinyl chloride (PVC) pipes with a length of 197 cm, a diameter of 16 cm, and a slope of 4°. It was constructed from four PVC pipes. In semi-continuous irrigation treatment, nutrients flow four to six times for each of ten minutes depending on plant development and the estimated evapotranspiration occurring, while in a continuous nutrient system the nutrients are streamed for twenty-four hours without stopping at a maximum flow rate of 13.7 L per second.

Using fresh water with small amount of air bubbles of size as small as a pencil dot, the existing flow meter in the flow system (hydraulics) was proved using the Sierra Ultrasonic meter (Innova-SonicTM Model 210i) with measurement medium taken at ambient temperature of 30oC. The procedures for installation of the ultrasonic meter were followed and measurement taken with transducers mounted using V-method and N-method respectively, on a pipe size of 20mm. The V-method and N-method gave average flow rates of 0.02918cf/sec and 0.04402cf/sec respectively. The V-method resulted in a meter factor of 1.9610, while the N-method resulted in a meter factor of 3.2511. The V-method and N-method gave relative percentage error values of 49% and 69.2% respectively. The V-method proved to be suitable for the pipe size of 20mm used in the experiment, with standard deviation of 5.3339x10-4 and variance of 2.84505x10-7 compared to standard deviation of 6.8x10-3 and variance of 4.624x10-5 obtained from N-method. It is recommended that a meter factor of 1.9610 obtained from V-method be applied on the existing meter. The liquid flow rates at measurement medium temperatures of 50oC and 70oC were determined by the use of poly-vinyl chloride and steel pipes respectively. It was observed that fluid flow rate increased with increase in temperature, and flow rate determined with ultrasonic flowmeter depends on material type as flow through poly-vinyl chloride pipe was generally higher compared with steel pipe at the temperatures values considered.