Large High Density Polyethylene Research Articles

냉각해석기술을 접목한 HDPE(고밀도폴리에틸렌) 후육 멀티리듀서 사출금형 개발

A large high density polyethylene (HDPE) multi-reducer is designed as a multi-joint pipe with seven different thicknesses, as a part for connecting HDPE pipes of different diameters. The multi-reducer prepared in this study weighs more than 30 kg per product, it has a wide range of thicknesses reaching 180 mm in the thickest part; till now, no attempts have been devoted toward the production of such a large multi-reducer via molding. The result of cooling analysis of the 3D mold designed to obtain a high-quality product showed that because of the large amount of the raw material injected into the mold, pores and defects such as shrinkage, depression, shape dimensional deformation are formed owing to non-uniformity in the temperature distribution. In order to verify the theoretical shrinkage and cooling deformation that occur during thick injection molding, the test product was measured, and the design technology considering the final shrinkage and strain was reflected in the cavity and core revision design. The thick products with a large difference in thickness are more deformed during cooling; therefore, we focused on the cooling channel design. Through a series of experiments, we were able to successfully develop a HDPE-based thick multi-reducer for large products that has never been prepared before.

Suggestion of coherent radio reflections from an electron-beam induced particle cascade

Testbeam experiment 576 (T576) at the SLAC National Accelerator Laboratory sought to make the first measurement of coherent radio reflections from the ionization produced in the wake of a high-energy particle shower. The >10 GeV electron beam at SLAC End Station A was directed into a large high-density polyethylene target to produce a shower analogous to that produced by an EeV neutrino interaction in ice. Continuous wave (CW) radio was transmitted into the target, and receiving antennas monitored for reflection of the transmitted signal from the ionization left in the wake of the shower. We detail the experiment and report on preliminary hints of a signal consistent with a radio reflection at a significance of 2.36$\sigma$. We recommend another test-beam measurement in order to verify the signal.

Storage-induced deterioration of domestic water quality

Abstract Due to the failure of municipal supply systems in many Nigerian cities, residents often resort to long storage of water in large high-density polyethylene (HDPE) tanks in order to reduce water stress. This paper investigated deterioration of the quality of stored water for a period of 35 days. Samples from 20 purposively selected storage tanks in Enugu, Nigeria were collected for analysis. Heterotrophic bacteria, total coliform (TC), enterococci and Escherichia coli were present in 85%, 75%, 40% and 61% of the samples, respectively. E. coli (p < 0.001) and heterotrophic plate count (HPC) (p < 0.001) were significantly higher in storage tanks that were also used for rainwater collection than those that were not. HPC and TC counts in tanks that collect rainwater were twice those of tanks that do not, while E. coli and enterococci counts in tanks that also collect rainwater were three times those of tanks that do not collect rainwater. The most significant change (p < 0.001) in E. coli concentration occurred after 15 days of storage. Cleaning of tanks caused significant reduction of TC counts (p = 0.013), E. coli (p < 0.001), HPC (p < 0.001) and enterococci (p = 0.001). Hence, prolonged storage of water causes significant deterioration of water quality.

Quantifying capital goods for collection and transport of waste

The capital goods for collection and transport of waste were quantified for different types of containers (plastic containers, cubes and steel containers) and an 18-tonnes compacting collection truck. The data were collected from producers and vendors of the bins and the truck. The service lifetime and the capacity of the goods were also assessed. Environmental impact assessment of the production of the capital goods revealed that, per tonne of waste handled, the truck had the largest contribution followed by the steel container. Large high density polyethylene (HDPE) containers had the lowest impact per tonne of waste handled. The impact of producing the capital goods for waste collection and transport cannot be neglected as the capital goods dominate (>85%) the categories human-toxicity (non-cancer and cancer), ecotoxicity, resource depletion and aquatic eutrophication, but also play a role (>13%) within the other impact categories when compared with the impacts from combustion of fuels for the collection and transport of the waste, when a transport distance of 25 km was assumed.