Polyethylene Pellets Research Articles

Infrared data of sulphides of interstellar dust importance

In the last decade the existence of a prominent 30 μm emission feature in the IR spectra of carbon-rich sources has been confirmed. It was tentatively identified with the characteristic lattice vibration band of magnesium sulphide. Meanwhile, the observational material has considerably increased, but optical data of relevant sulphide materials are not available. In this paper optical data of Mg-Fe sulphides have been determined to provide the base for a thorough proof of the identification proposal and for theoretical modelling of the source spectra. Samples of the system Fe x Mg 1− x S( x = 0.1… 1) have been prepared in the laboratory. Subsequently, the materials have been characterized structurally by X-ray diffraction, scanning electron microscopy and energy dispersive micro-probe analysis. These samples have been studied IR-spectroscopically by measuring the reflectance of polished surfaces and the transmittance of small particles embedded in polyethylene pellets. From the reflectance spectra optical data in the wavenumber range 1000−20 cm −1 have been derived. Extinction coefficients of small spheres and a continuous distribution of ellipsoids in polyethylene calculated from these data have been compared with the measured transmission spectra. The emission of small FeMg sulfide particles has been calculated and compared with an observed spectrum.

Research of Swirling Flow Pneumatic Conveying System in a Vertical Pipeline. Overall Pressure Drop and Flow Patterns.

An experimental study is carried out for a swirling flow pneumatic conveying system in a vertical pipeline in terms of the overall pressure drop and solid flow patterns. The test section consists of a pipeline 12 m in height with an inside diameter of 80mm. Measurements were made for three initial swirl numbers from 0.58 to 1.12, the average gas velocities from 9 to 23 m/s and the solid-gas ratios from 1.5 to 23. Polystyrene, polyethylene and polyvinyl pellets with mean diameters of 1.7, 3.1 and 4.3 mm, respectively, were transported as test particles. It is found that in lower gas velocity range, the overall pressure drop for swirling flow pneumatic conveying was close to that for axial flow pneumatic conveying and that wall static pressure of the former was lower than that of the latter.

Research of Swirling Flow Pneumatic Conveying System in a Vertical Pipeline. (Coefficients of Power Consumption and Additional Pressure Drop).

An experimental study is carried out for a swirling flow pneumatic conveying system in a vertical pipeline in terms of the power consumption and additional pressure drop. The test section consists of a pipeline 12m in height with an inside diameter of 80 mm. The three initial swirl numbers from 0.58 to 1.12, the average gas velocities from 9 to 23m/s and the solid-gas ratios from 1.5 to 23 were investigated. Polystyrene, polyethylene and polyvinyl pellets with mean diameters of 1.7, 3.1 and 4.3 mm, respectively, were transported as test particles. It is found that the critical and minimum gas velocities of swirling flow pneumatic conveying were lower than those of axial flow pneumatic conveying, the maximum reduction rates being 13% and 20%, respectively. In the lower gas velocity range, the power consumption and additional pressure drop were decreased by the swirling flow pneumatic conveying.

IR spectrometric determination of concentrations of soluble and insoluble fractions of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate in polymers: application to LDPE films

The method described is based on the shift of the carbonyl absorption in the IR spectrum of the ester groups of this hindered aliphatic amine stabilizer when it is soluble or bloomed as a surface solid phase. It is shown that the values of the extinction coefficient to be used for the calculation of these concentrations are: ε solute = 580 cm −1 mol −1 litre at λ max = 1736 cm −1, and ε solid = 945 cm −1 mol −1 litre at λ max = 1718 cm −1. Quenching of the films after processing or any other heat treatment may lead to higher, non-equilibrium values of the soluble part of this additive. The resulting annealing effect must not be overlooked. IR measurements were done at room temperature (23 ± 2°C) on extruded blown films obtained from mixtures of low density polyethylene (LDPE) pellets with this powder additive (≤0·5 wt%).

A Numerical Simulation of Swirling Flow Pneumatic Conveying in a Horizontal Pipeline.

A numerical simulation for axial and swirling flow pneumatic conveying in a horizontal pipe is carried out with an Eulerian approach for the gas and a stochastic Lagrangian approach for particles, where particle-particle and particle-wall collisions are taken into consideration. The k-e turbulence model is used to characterize the time and length scales of the gas-phase tubulence. Models are proposed for predicting the particle source and additional pressure loss. The numerical results are presented for polyethylene pellets of 3.1 mm diameter conveyed through a pipeline of 13 m in length with an inner diameter of 80 mm. It is found that numerical results agree with our measurements.

Barley bran flour accelerates gastrointestinal transit time

The effect of barley bran flour on colon physiology was studied in 44 volunteers. Twenty-two subjects followed the National Cholesterol Education Program (NCEP) step 1 diet supplemented with 20 g cellulose and the other 22 followed the NCEP diet supplemented with 30 g barley bran flour. To measure gastrointestinal transit time, subjects ingested 20 polyethylene pellets impregnated with barium sulfate in two gelatin capsules. Subjects collected fecal samples for 5 days during the baseline period and again during the period of fiber supplementation. Each stool sample was radiographed, and the number of recovered markers was used to calculate mean transit time. Daily fecal weights were recorded and dry weights were determined. The group that consumed barley bran flour significantly decreased transit time by 8.02 hours from baseline, whereas the group that consumed cellulose increased transit time by 2.95 hours from baseline. Similarly, cellulose supplementation did not result in increased fecal weight, whereas daily fecal weight increased significantly by 48.6 g with supplementation with barley bran flour. This study shows that barley bran flour accelerates gastrointestinal transit and increases fecal weight.

Vibrational Assignment of N-Phenylphthalimide and15N-Phenylphthalimide

Abstract The i.r. spectra of N-phenylphthalimide and 15N-phenylphthalimide have been measured in 4000–100 cm−1 frequency range as KBr and polyethylene pellets and as chloroform solutions. The Raman spectra (4000–50) cm−1 of microcrystalline powder of the of the same compounds have also been investigated. A detailed assignment of most of the observed frequencies has been proposed on the basis of the group vibrational concept, isotopic shift data and analogies with the spectra of related molecules. Some literature data have been discussed and some frequencies are reassigned.

Research of Swirling Flow Pneumatic Conveying System in a Horizontal Pipeline. 3rd Report, Coefficients of Power Consumption and Additional Pressure Drop.

Polystyrene, polyethylene and polyvinyl pellets with mean diameters of 1. 7, 3. 1 mm and 4. 3 mm, respectively, were transported as test particles in a swirling flow pneumatic conveying system consisting of a horizontal pipeline of 13 m length and 80 mm inner diameter. The initial swirl number was varied from 0. 58 to 1. 12, the mean air velocity from 9 m/s to 24 m/s and the solid mass flow rate from 0. 43 kg/s to 1. 17 kg/s. It is found that the critical and minimum air velocities of swirling flow pneumatic conveying are lower than those of axial flow pneumatic conveying, the maximum reduction rates being 13% and 17%, respectively. In the lower air velocity range, the power consumption and additional pressure drop are decreased by the swirling flow pneumatic conveying system.

Research of Swirling Flow Pneumatic Conveying System in a Horizontal Pipeline. 2nd Report. Particle Velocity and Concentration Profiles.

Measurements of particle velocity and concentration profiles for a swirling flow pneumatic conveying system in a horizontal pipeline with a length of 13 m and an inner diameter of 80 mm have been made by photographic methods. Polyethylene and polyvinyl pellets, with mean diameters of 3. 1 mm and 4.3 mm, respectively, were transported as test particles. The initial swirl numbers were varied from 0.58 to 1.12, the mean air velocities from 9 m/s to 24 m/s and the solid-gas ratios from 0.8 to 3.0. It was found that in the acceleration region the mean particle velocity for the swirling flow pneumatic conveying system was higher than that for the axial flow pneumatic conveying system in the lower air velocity range and was lower in the higher air velocity range. The change of the mean particle velocity against the mean air velocity for the swirling flow pneumatic conveying system was smaller than that for the axial flow pneumatic conveying system. With swirling flow, the particle velocity profiles became uniform and the concentration profiles became symmetrical with respect to the pipe axis.

Repellency of polyethylene pellets containing menthol and methyl salicylate to cats

Repellency of polyethylene pellets containing menthol and methyl salicylate to cats

Research of Swirling Flow Pneumatic Conveying System in a Horizontal Pipeline. 1st Report. Pressure Drop and Flow Patterns.

An experimental study is carried out for a swirling flow pneumatic conveying system in a horizontal pipeline in terms of the pressure drop and solid flow patterns. The test section consists of a pipeline 13m in length with an inside diameter of 80mm. The three inital swirl numbers in the range of 0.58 to 1.12, the average gas velocity from 10m/s to 23m/s and the solid-gas ratios ranging from 3.5 to 14 were investigated. Polyethylene pellets of 3.1mm were used as the solids conveyed. It is found that in the lower gas velocity range, the pressure drop and the gas velocity at the pressure drop minimum for swirling flow pneumatic conveying were lower than those for axial flow pneumatic conveying. The fluctuation of wall static pressure of swirling flow pneumatic conveying decreases compared with axial flow pneumatic conveying.

Chemical Method for the Determination of Starch in Polyethylene

Abstract A chemical/spectrophotometric procedure has been developed that allows the determination of starch and some modified starches (as glucosyl residues) in polyethylene films and pellets. The method uses samples containing up to 60 mg polyethylene and determines the anhydrous starch content of samples possessing starch loads in the range typically encountered with degradable plastics (5–40%). The method consists of dissolution of the polyethylene component into decahydronapthalene (decalin) at 150[ddot]C followed by solubilization with partial hydrolysis of the starch component in 1M HCl at 100[ddot]C. An aliquot of the resulting starch hydrolyzate is analyzed for total carbohydrate using the phenol-sulfuric acid method. The method has been tested on two sets of specially prepared starch-polyethylene films as well as on several commercial products.

Thermal analysis of polymer samples by round robin method: Part II. factors affecting heats of transition

The results of a round robin test (RRT) of heats of melting (Δ H m) and heats of crystallization (Δ H c) of polymers have been analysed. Fourteen laboratories participated in the RRT. Three kinds of polymer were tested: two samples of polyethylene (pellets and film), with the same origin but a different thermal history; two samples of poly(ethylene terephthalate) fibre; and poly(ether ether ketone) pellets. Eight types of differential scanning calorimeter (DSC) were used. Seven of these were power-compensate type DSCs and seven were heat-flux type DSCs (quantitative DTAs). The standard deviations of (Δ H m) and (Δ H c) were correlated with various factors. In particular, the heats of transition of all samples were directly correlated with the temperature width between the measured onset and end temperatures of transition. Variation in the values of heats of transition obtained could be mainly attributed to variation of the measured onset temperature of melting or the measured end temperature of crystallization. Two experimental procedures are suggested as a means of decreasing this variation.

Thermal analysis of polymer samples by a round robin method: I. Reproducibility of melting, crystallization and glass transition temperatures

The reproducibility of transition temperatures (melting, crystallization and glass transition temperatures) of polymers determined by thermal analysis was examined by a round robin method, in which twenty three laboratories participated. Seven polymer samples were used for the test, which consisted of polyethylene pellet and film, two poly(ethylene terephthalate) fibers, poly(ether ether ketone) pellet, polystyrene sheet and poly(ether sulfone) pellet. Eight types of instrument were employed including 13 power-compensated type differential scanning calorimeters and 8 heat-flux type ones (quantitative differential thermal analyzers). For the first-order transition such as melting and crystallization, the values of the peak melting and crystallization temperatures ( T pm and T pc) and the extrapolated onset and end temperatures ( T im and T ic, and T em and T ec) agreed well among laboratories. The standard deviations (σ n ) were smaller than 3.0 K for T pm, T pc, T im and T em, and T ic and T ec with a few exceptions. However, the onset and end temperatures ( T' im and T' em, and T' ic and T' ec) are so scattered that it is reasonable to use T pm, and T pc, and T im, and T em, and T ic and T ec for the comparison of data obtained for polymers by thermal analysis in separate laboratories. For glass transition, the σ n values were within 3.1 K for the extrapolated onset temperature ( T ig) and the midpoint temperatures ( T mg), but the onset and end temperatures ( T' ig and T' eg) and the extrapolated end temperature ( T eg) were very scattered. Therefore, it is appropriate to use T ig and T mg to compare the data from different sources.

Microwave measurement of the mass of frozen hydrogen pellets

A nondestructive method for measuring the mass of high-speed, frozen hydrogen pellets is described. The measurement technique is an improvement on previous methods based on the perturbation to a resonant cavity caused by a dielectric pellet passing through the cavity. In the new method, an oscillator circuit is formed with a resonant cavity in the positive feedback loop of a microwave power amplifier. An injected pellet perturbs the resonance characteristics of the cavity causing a shift in the operating frequency of the oscillator proportional to the ratio of the pellet volume to the volume of the cavity. Through digital measurement of the frequency shift the size of the pellet is determined automatically. In a ‘‘proof-of-principle’’ experiment it was shown that polyethylene pellets, with an average volume of 0.26 mm3 and velocity ≊500 m/s, caused a shift in the operating frequency of the oscillator circuit that was within 10% of the predicted value. The hydrogen pellets (of interest to us) will have 4–10× the volume of the plastic pellets. Thus with a dielectric constant of about 1.26 for frozen hydrogen, the signals in the actual experiment would be 1–2× those described here.

Effects of ingested plastic on seabird feeding: Evidence from chickens

Domestic chickens Gallus domesticus were fed polyethylene pellets to test whether ingested plastic impairs feeding activity. When food was temporally limited, plastic-loaded birds ate less than control birds, apparently as a result of reduced gizzard volume. When given food ad libitum, plastic-loaded birds also ate less and grew slower than did control birds. It is concluded that ingested plastic reduces meal size and thus food consumption when plastic reduces the storage volume of the stomach. This reduced food consumption may limit the ability of seabirds with large plastic loads to lay down fat deposits, and thus reduce fitness.

Far-infrared absorption spectra of Ni, Co and Fe dihalides hydrates

The optical absorption spectra of NiCl 2 · 6H 2O, CoCl 2 · 6H 2O, CoBr 2 · 6H 2O, FeCl 2 · 4H 2O and NiI 2 · 6H 2O, dispersed in polyethylene pellets, were recorded at 8̃0K in the far-infrared (50–400 cm −1) energy region. In these spectra we identified the peaks related to the translations of the lattice water and iodine (if present) and to the deformation modes of the MX 2·4H 2O or M(H 2O) 6 octahedron. Concerning the latter ones, a further distinction of the metal-oxygen and metal-halogen “stretching” with respect to the “bending” type modes was proposed.

The lifespan of ingested plastic particles in seabirds and their effect on digestive efficiency

The assimilation efficiencies of fledgling Whitechinned Petrels Procellaria aequinoctialis artifically fed large quantities of plastic particles were assessed. No significant differences were detected in either assimilation efficiency or the rate of mass loss between experimental and control birds. Polyethylene pellets lost 1% of their mass after 12 days in the experimental birds' stomachs, suggesting a half-life of at least one year. No instances of plastic causing intestinal obstruction, and few cases of physical damage to the stomach lining, were found in over 400 individuals of 25 species of seabirds containing ingested plastic. These results suggest ingested plastic seldom impairs digestive efficiency in seabirds.

Carbon tetrachloride absorption in low-density polyethylene pellets: Concentration profiles by electron microprobe analysis

The concentration profiles of carbon tetrachloride in low-density polyethylene pellets after various periods of absorption (1–6 h) at 40°C have been measured in a new application of electron probe microanalysis using energy dispersive x-ray spectroscopy (EDAX). The concentration profiles were determined from an EDAX scan of chlorine content along the diameter of a cylindrical pellet (4-mm diameter) mounted in a scanning electron microscope. The maximum chlorine content seen in the EDAX scan was presumed to reflect the equilibrium surface concentration, eliminating the need to calibrate the system and enabling direct interpretation of the EDAX scan as a concentration profile. The concentration profiles revealed that absorption of CCl4 in LDPE pellets took place with a sharp moving boundary, with the depth of penetration proportional to (time)½ rather than to time as in case II diffusion. This behavior was attributed to a discontinuous relationship between diffusivity and concentration, resulting in a sharper than expected fickian diffusion profile. The EDAX technique, although requiring further refinement, appears to be a valuable method for assessing slow diffusion in thick polymer samples for those penetrants detectable by EDAX.

Sorption of carbon tetrachloride in low‐density polyethylene pellets

AbstractUnsteady‐state conjugate sorption curves for carbon tetrachloride in low‐density polyethylene (LDPE) pellets at temperatures between 40 and 70°C suggested there was a maximum in the diffusivity‐concentration relationship at high values of concentration. The sorption curve at 70°C also displayed features characteristic of pseudofickian behavior, which was attributed to clustering of the penetrant at the high vapor acitivity corresponding to this temperature.