Diameter Plastic Pipe Research Articles

Evaluation of arched EPS block and geocell inclusions in trench backfill for protection of buried flexible pipes

This paper presents an experimental investigation examining the novel idea of employing curved expanded-Polystyrene (EPS) blocks that arch around the upper section of buried flexible pipes to reduce the pressures acting on them and hence resulting deformation/deflections. Large-scale testing was performed to examine key performance indicators for reinstated trenches with buried 250-mm diameter plastic pipe (0.75-m invert depth) when subjected to cyclic surface loading simulating vehicular traffic. The real-scale model tests investigated unreinforced and geocell-reinforced trenches with conventional rectangular and differently shaped EPS block inclusions placed above the crown or fitting snugly around the upper section of the buried pipes. Compared to conventional rectangular EPS block, the curved-arched EPS block produced greater reductions in the pressures acting on the buried pipes, resulting in substantially smaller pipe deformation/deflections. The geocell layer overlying the EPS block significantly reduced the pressures bearing on the highly compressible EPS material, thereby reducing its compression and the trench surface settlement. Optimum trench reinstatements incorporated both the geocell layer and a 75-mm thick curved-arched EPS block fitted around the top section of the pipe. Doubling the EPS block thickness produced only modest reductions in the pipe deflections, but significantly increased the trench surface settlement.

Stem-nesting Hymenoptera in Irish farmland: empirical evaluation of artificial trap nests as tools for fundamental research and pollinator conservation

Insect pollinators are suffering global declines, necessitating the evaluation and development of methods for long-term monitoring and applied field research. Accordingly, this study evaluated the use of trap nests (“bee hotels”) as tools for investigating the ecology of cavity nesting Hymenoptera within Irish agricultural landscapes. Three trap nests consisting of 110 mm diameter plastic pipe containing 100 cardboard nest tubes of varying diameter were placed at eight apple orchards and eight oilseed rape sites and left in the field for five months. Sealed nest tubes occurred at 15 of the 16 sites, and in 77% of the 48 nests. However, only 7% of the 4800 individual nest tubes were sealed, and only 4% produced cavity-nesting Hymenoptera. Three cavity nesting bee species (Hylaeus communis, Osmia bicornis, Megachile versicolor) and two solitary wasp species (Ancistrocerus trifasciatus, A. parietinus) emerged from nest tubes. There were significant differences among species in terms of emergence date and the diameter of nest tubes from which they emerged, the latter allowing the calculation of niche width and niche overlap, and informing choice of tube size in future studies/conservation efforts. Trap nests, therefore, offer a valuable tool for fundamental ecological research and a model system for investigating interactions between stem-nesting species within their wider ecological networks. The ability of trap nests to actually increase farmland pollinator abundance and diversity as part of agri-environment schemes requires additional investigation. However, used in sufficient numbers, these trap nests provide valuable biogeographical data for cavity nesting Hymenoptera and offer a viable means for long term monitoring of these species in Irish farmland.

Recent Patents on How to Form or Manufacture Large Diameter Plastic Pipe

Background: In recent times, large diameter plastic pipes have been widely used in many functions because of their unique advantages. These applications include water supply, drainage, heating network, industrial transportation, gas delivery, agricultural irrigation, etc. Therefore, manufacturing large diameter plastic pipes economically and efficiently has now become an important research area. Objective: This paper reviews patents of plastic pipe manufacturing or forming to provide insights and references to researchers in the domain of larger diameter plastic pipe production. Methods: This paper reviews the Spouted-accumulated Forming, a production method that combines the advantages of traditional extrusion, calendaring, and additive manufacturing. It is a novel process to manufacture large diameter plastic pipes. Results: The experiment result shows that Spouted-accumulated Forming can be used to manufacture large diameter plastic pipes efficiently with lower costs. This paper argues that this novel method will serve as a promising technology to manufacture larger diameter pipes in the future. Conclusion: Since traditional manufacturing processes cannot fulfil the requirement of large diameter of plastic pipes, it is necessary to develop novel processes such as Spouted-Accumulated Forming (SAF, based on additive manufacturing).

Small root exclusion collars provide reasonable estimates of root respiration when measured during the growing season of installation

A common method to determine in situ root respiration is to insert root exclusions to sever roots and then to measure soil carbon dioxide (CO2) efflux in and outside the exclusion. We report the use of relatively small root exclusions (15.2 cm diameter plastic pipe) (SREs), installed and measured within a growing season. We switched from long-used, large root exclusions (2.5 m × 3 m) (LREs) for three reasons. First, temperature artifacts were apparent in LREs, likely because increased soil moisture altered soil thermal balance. Second, LREs in dense stands required a relatively low tree density, which then impacted snowpack depth and insolation. Third, the LREs were much more time-consuming to install than SREs. Using a powered mechanical trencher (ditch witch®) decreased LRE installation time, but introduced a large edge-effect apparent in soil profile pCO2 that would obviate trenched plots smaller than 1600 cm2. However, when trenches were dug by hand, the distance from the LRE wall had no effect on soil pCO2. In a subsequent experiment, SREs were installed by cleanly cutting the forest floor, and then immediately measured. Within 1-3 weeks the SREs provided similar root respiration estimates to those made with LREs that had been in place for nearly 10 months. SREs placed in and outside LREs provided indistinguishable microbial respiration values from one another and to the LREs. We conclude SREs provide root respiration estimates indistinguishable from other methods, even when installed and measured within the same growing season.

Energy Loss at Combining Pipe Junction

Energy loss data for a 90° sharp-edge combining pipe junction were obtained, using a 37-m long, 444-mm diameter plastic pipe with a branch pipe entering about 35 pipe diameters downstream from the upstream end of the pipe. The data cover ratios of branch to main-pipe cross-sectional areas \IA\N\Db\N/\IA\N\Dd\N ranging from 0.02 to 0.21 and ratios of branch to main-pipe discharge \IQ\N\Db\N/\IQ\N\Dd\N ranging from 0 to 1. At flow situations defined by these ranges there are few energy loss data available and no satisfactory theory. The study includes an investigation of specific flow features at the junction including the velocity and pressure distribution in the branch flow at its exit into the main pipe. A momentum analysis is performed to show that a satisfactory description of the momentum balance must include the momentum contributions associated with: (1) The deflection and distortion of the branch-flow velocity distribution prior to the exit of the branch flow into the main pipe; and (2) the increase in wall shear stress in the main pipe due to the local deformation of the main-flow velocity distribution. The data show that the fully developed pipe flow is re-established about 50 pipe diameters downstream from the pipe junction.

Relationship between number of conditioning trials per training session and avoidance learning in horses

Sixteen horses were used to determine if number of trials given per training session (5, 10, 15 or 20) affected learning performance in an avoidance conditioning task. The horse had to move from one side of a test pen to the other during an auditory cue presentation to avoid aversive stimulation. A pen 8 m×3.6 m, divided into two equal sections by a 13-cm diameter plastic pipe lying on the ground, was used as the test pen. Painted plywood panels were fastened to the fence in half the pen to help horses distinguish visually between the two parts. A 10-s auditory cue was used as a signal for horses to move from one side of the test pen to the other. A 20-s intertrial interval was used. Training sessions were conducted every third day. Each trial was recorded as an avoidance (the horse completed the task during auditory cue presentation and avoided aversive stimulus) or an error (the horse received aversive stimulus). After completing ten consecutive avoidances (criterion), the horse was removed from the study. Numbers of training sessions, trials, avoidances and errors until reaching criterion were recorded for each horse. Horses varied greatly within these variables with ranges of 3–18 sessions, 37–121 trials, 20–68 avoidances and 17–53 errors to criterion. No differences were detected ( P>0.05) in the number of conditioning trials per training session (treatment) for the mean number of trials, avoidances or errors to criterion. Number of training sessions to criterion differed ( P<0.01) among treatments, indicating that an optimum number of learning trials per training session might exist. Mean sessions to criterion for horses receiving 5, 10, 15 and 20 trials per session were 15.1±1.3, 5.8±1.1, 5.3±1.1 and 4.6±1.1, respectively. Regression analysis indicated that 16.2 trials per training session would minimize number of sessions to criterion. Although it is widely assumed that learning efficiency in horses is decreased when intense activity is concentrated into a small number of sessions, these results indicate that moderate repetition of training activities is needed for efficient learning.

Fatigue testing of GRP and UPVC pipes subjected to pressure surge

There is considerable interest in replacing metal pipes with plastic pipework. The perceived advantages are: (a) it is lightweight and easy to handle, (b) it is chemically inert to many materials, (c) it is relatively easy to join. However, before any replacements can be considered tests have to be conducted to ensure the pipes are capable of withstanding any surge pressures that are likely to occur. This paper gives details of a test programme to investigate the effect of surge pressures on the survivability and damage resistance of 0.15 m diameter plastic pipe (GRP and uPVC). The objectives of the project were to apply surge pressures to investigate6the effect of repeated surges i) at less than the failure pressure, and ii) to measure the failure pressures within the test facility limitations. The tests were conducted in the BHR Group pressure surge test facility. This unique, (‘Bustapipe’) relies on a collapsing vapour cavity to generate large pressure surges. The Bustapipe facility is pressure rated to a maximum of 40 bar. Both the surge pressure and duration can be varied in order to investigate the influence of these on the pipe behaviour. The tests demonstrated that plastic pipes can quite safely take the place of metal pipes provided care is taken over the selection of plastic type and method of construction.

Measurement and estimation of evaporation from soil under sparse barley crops in northern Syria

Increased yields of rain-fed barley grown in northern Syria have been produced by the application of phosphate. It has been suggested that enhanced early growth of the fertilised plants restricts evaporative loss from the soil surface, improving water-use efficiency by decreasing the ratio of evaporation from the soil to transpiration ( E/T). The objective of this study was to evaluate the use of micro-lysimeters for direct measurements of E from the soil beneath barley canopies. The lysimeters were made from sections of 10-cm diameter plastic pipe, 15 cm in length. Daily E from fallow and cropped (leaf area index ( LAI) ⩽ 2) soil surfaces was measured for 100 days to crop maturity. Evapotranspiration ( ET) was determined by water balance from neutron probe readings, allowing the performance of micro-lysimeters in the bare soil treatment to be checked. Over rain-free periods, the micro-lysimeter and water balance measurements agreed to within ± 0.25 mm day −1. Over periods when rain fell, E measured by micro-lysimeter was 0.1–1.1 mm day −1 less than E from water balance. A simple method was devised to estimate E in all treatments on wet days; these estimates were used to replace micro-lysimeter measurements on days when rainfall exceeded 1 mm. Fertiliser application had little impact on total ET, but total E was reduced by 10%; E accounted for 67 and 77% of total ET in the fertilised and unfertilised treatments, respectively. A large fraction of total E occurred on days when rain fell, emphasising the need to achieve accuracy over rainy periods before micro-lysimetry can be used successfully to monitor E through the duration of a rain-fed crop. The dataset of daily E was used to examine two previously published methods for estimating E from crop, soil and meteorological data. The performance of both methods is discussed.

Simple and Accurate Friction Loss Equation for Plastic Pipe

The Blasius equation which has been verified by many researchers and has been recently shown to work very well for small diameter plastic pipe can be combined with the Darcy-Weisbach equation to give a simple and accurate equation written in terms of flow rate, pipe length, and pipe diameter. It allows for correcting for viscosity changes, and is very accurate for flows resulting in Reynolds numbers less than 100,000. Unlike other commonly used empirical equations in a similar form, this equation is theoretically sound and dimensionally homogeneous.

Friction Factors for Small Diameter Plastic Pipes

Friction loss data were collected for three small diameter plastic pipe sections. Analysis of the data confirmed that the Blasius equation is a very accurate predictor of the friction factor when Reynolds numbers are less than 100,000. The theoretical basis for a power-law relationship of the friction factor to Reynolds number is discussed, and the agreement of the 1/7th power law with the Blasius exponent exponent (-0.25) is pointed out. A combination of the Blasius and Colebrook-White equations is proposed as a convenient and accurate head loss prediction equation. The combination equation is dimensionally homogeneous, correctable for viscosity changes, and accurate for small diameter plastic pipe as it is normally used.

Study on Prevention of Breast Blister in Broilers, with Special Reference of Flooring Structures and Materials for Caged Broilers

Six experiments were conducted to study the effect of various flooring types on the incidence of breast blister in cage-reared broilers. Broilers were grown from four to ten weeks of age on each type of the experimental floor.In these experiments the incidence of breast blister was influenced by flooring types. Wire I (1.7×12.0cm) floor produced broilers with more breast blisters and more severe breast blisters than the other floor types. Broilers reared on a large mesh floor had a higher incidence of the breast blisters than broilers on small mesh floor, but less waste and feather could drop through the small mesh (1.0×1.0cm). Broilers reared on lattice type floor made of plastic pipe and bamboo had a comparatively lower incidence of breast blister. In these lattice type floors broilers reared on flat plastic pipe (splited a 32mm diameter plastic pipe in 1/4 lengthwise, and splited a 60mm diameter plastic pipe in 1/8 lengthwise) had more breast blisters than broilers on round plastic pipe (splited a 22mm diameter in 1/2 lengthwise). Broilers reared on strips spaced 1.5cm apart had significantly (P<0.01) more breast blisters than broilers on its spaced 1.0cm apart.The male broiler had a significantly (P<0.01) higher incidence of breast blisters than the female broiler in all trials.