Polyethylene vial

For the analyses given in Table 1, samples were contained in special polyethylene vials specifically designed to fit the Kaman Nuclear dual-axis rotator assembly. These vials are 4,5cm long and 1.0cm o.d. with an internal volume of 2.3cu cm. When filled, a vial contains approx 0,5g of NC and 2.3g of TNT or HMX. 

For single-axis rotation, a special lucite wheel is used designed to hold up to 12 small polyethylene vials contg expl. The wheel is manually mounted in front of the accelerator target before irradiation, and manually removed after irradiation for counting the samples... 

A typical procedure for Na assay is One gram proplnt samples sealed in polyethylene vials are irradiated for at least seven hrs in the thermal column. In order to minimize any thermal neutron flux gradient, the samples are rotated uniaxially at 60 rpm. Following irradiation, the samples are allowed to decay for approx 15 hrs to permit all short-lived radioisotopes to decay to insignificance. The 1.369 MeV 7-photopeak of each sample is then counted for 10 min with a 7.6cm x 7.6cm Na iodide scintillation detector coupled to a 400-channel pulse-height analyzer... 

The dry filter paper samples contained in polyethylene vials were irradiated for 2 to 5 min at a thermal neutron flux of 1013n/cm2-sec using the... 

With regard to the hazard concern from physical and mechanical handling, the expl nature of the materials can pose a special problem. For example, during pneumatic transfer of samples in fast neutron activation, the polyethylene vials containing the expl approach speeds of 15m/sec and come to rest against a metal stop at both irradiation and count stations. However at PicArsn (Ref 13), in over 1000 irradiations and pneumatic transfers with up to 2.3g of shock-resistant secondary expls such as TNT, HMX,... 

Cranston and Murray [35,36] took samples in polyethylene bottles that had been pre-cleaned at 20 °C for four days with 1% distilled hydrochloric acid. Total chromium Cr(VI) + Cr(III) + Crp (Crp particulate chromium) was coprecipitated with iron (II) hydroxide, and reduced chromium Cr(III) + Crp was co-precipitated with iron (III) hydroxide. These co-precipitation steps were completed within minutes of the sample collection to minimise storage problems. The iron hydroxide precipitates were filtered through 0.4 pm Nu-cleopore filters and stored in polyethylene vials for later analysis in the laboratory. Particulate chromium was also obtained by filtering unaltered samples through 0.4 pm filters. In the laboratory the iron hydroxide co-precipitates were dissolved in 6 N distilled hydrochloric acid and analysed by flameless atomic absorption. The limit of detection of this method is about 0.1 to 0.2 nM. Precision is about 5%. 

A 3.5 ml portion in a 4 ml polyethylene vial was irradiated for 5 min. Another portion, 3.0 ml in a 3.5 ml silica vial, was irradiated for 3 d. After the short irradiation, 3 ml of the irradiated solution were transferred into an activity-free vial and submitted to y-ray spectrometry with a Ge(Ii) detector coupled to a 4000-channel analyser. After the long irradiation, the sample was allowed to cool for 3 d, then the surface of the silica ampoule was cleaned with dilute nitric acid and the sealed ampoule was placed in the counter (the background activity of the ampoule was negligible). Gamma-ray energy and the areas under peaks were calculated by computer. To determine the half-fives of the nuclides produced, the counting was repeated at appropriate intervals. 

The sample aliquots were encapsulated in polyethylene vials for the irradiation period. Two aliquots of the sample plus two standards were irradiated in a pneumatic transfer irradiation system, one set (sample plus standards) for a long time period (12-24 hrs) and the other for a short time period (5 min). After irradiation the samples were immediately removed from the vials. The short-time sample was counted after decay intervals of 3 min, 30 min, and 24 hrs. The long-time sample was counted after a decay interval of 3 wks sometimes the decay intervals were 7-10 days. The typical neutron flux was 1013 neutrons/cm2/sec. Counting data were processed through computerized data reduction codes. Twenty to thirty elements were reported. 

A few comments should make Figure 1 more understandable. The sample aliquot used for the 5-min irradiation was sealed in a polyethylene vial, tested for leaks, and irradiated 5 min. The other aliquot was flame sealed in the quartz vial, tested for leaks, and irradiated 3-12 hrs, depending on the sample type. The counting data from each aliquot were... 

Some problems developed in sample preparation and irradiation because of the variety of sample matrices submitted for INAA. Some samples were particulates (coal, fly ash, bottom ash, ore), some were volatile hydrocarbons (gasoline, jet fuel, etc.), some were aqueous, and some were solids. Our methods of sample preparation were refined to provide all samples in sealed quartz and polyethylene vials for irradiation (see Figure 1). Depending on the contents of the quartz vials, the length of irradiation was varied from 3-12 hrs to minimize vial breakage from... 

Table V presents average results on impurity levels of 16 polyethylene vials. Vials were 5 cm long, with 6-mm i.d., and 9-mm o.d. The average weight of the sealed vial was 2.00 g. High density polyethylene was used because of its better radiation resistance. The high impurity levels in these vials for S, Na, Cl, K, Al, and Ca severely limited the sensitivity to these elements in gasoline and other volatile materials which had to be counted in the vials.

Polyethylene was also susceptible to picking up radionuclides from the primary coolant. This interference was eliminated by sealing the sealed polyethylene vials into heat-shrinkable tubing which was easily removed after sample irradiation. 

Samples which were counted in polyethylene and quartz vials required corrections for the impurity content of the vials. Standard libraries of vial and blank filter paper corrections were added to SPECTRA (see Tables II, III, and IV). We used indicators in the input data to each computer calculation to call out the proper correction library. The code used corrections for polyethylene vials, Suprasil vials, Whatman-41 filters (25.8 cm2), and combinations. The computer also did not print the value for an element in a sample if the microgram quantity was within two times the microgram value of the vial or filter paper. The value output was listed as less than the vial or filter paper value, corrected to proper units. With this restriction, some data were lost, but very small values which were the difference between two larger numbers were eliminated. For example, if a volatile sample plus vial gave a chlorine value of 9.4 fig, the chlorine value output by the computer for the sample would be less than 9.0 fig (referring to chlorine in Table V) rather than the difference of 0.4 fig. If the sample plus vial gave a chlorine value of 20 fig, the value output by the computer would be 11 fig. 

In the present study, 12 g from each sherd was collected. Glazes and other surfaces were mechanically removed to minimize contamination from glaze and other external compounds. Following this process, specimens were powdered and homogenized in a Spex Mixer (Mod. 8000) tungsten carbide cell mill for 12 minutes. Powdered specimens were transferred to clean polyethylene vials for transportation to the laboratory. 

Sampling and Measurements. The determination of dissolved actinide concentration was started a week after the preparation of solutions and continued periodically for several months until the solubility equilibrium in each solution was attained. Some solutions, in which the solubilities of americium or plutonium were relatively high, were spectrophotometrically analyzed to ascertain the chemical state of dissolved species. For each sample, 0.2 to 1.0 mL of solution was filtered with a Millex-22 syringe filter (0.22 pm pore size) and the actinide concentration determined in a liquid scintillation counter. After filtration with a Millex-22, randomly chosen sample solutions were further filtered with various ultrafilters of different pore sizes in order to determine if different types of filtration would affect the measured concentration. The chemical stability of dissolved species was examined with respect to sorption on surfaces of experimental vials and of filters. The experiment was performed as follows the solution filtered by a Millex-22 was put into a polyethylene vial, stored one day, filtered with a new filter of the same pore size and put into another polyethylene vial. This procedure was repeated twice with two new polyethylene vials and the activities of filtrates were compared. The ultrafiltration was carried out by centrifugation with an appropriate filter holder. The results show that the dissolved species in solution after filtration with Millex-22 (0.22 ym) do not sorb on surfaces of experimental materials and that the actinide concentration is not appreciably changed with decreasing pore size of ultrafilters. The pore size of a filter is estimated from its given Dalton number on the basis of a hardsphere model used in the previous work (20). 

Step 1. Immerse polyethylene vial in 2% sodium dichromate-HN03 solution for 3-4 hours. 

An aliquot of 5 mL of rainwater was placed into an acid washed polyethylene vial and transported via a 1 rabbit1 carrier to the reactor core which has a nominal neutron flux of 5 x lO- n cm 2 sec l. The samples were irradiated for five minutes. The irradiated vials were then transferred to inert vials which were placed at the snout of a 22% efficient APTEC detector coupled to a Caneberra Series 90 multichannel analyser and a pile up rejector unit. The resolution of the system was 2.1 KeV at the 1332 KeV cobalt peak. Typical dead times were 10% or less. The samples had an average delay time of 100 seconds and were counted for a period of 10 minutes. 

The synthetic blend identical in composition to the H. subflexa gland extract (.see earlier) formulated in either polyethylene vials (30 mg of mixture) or on filter paper (75 ng) was as effective in capturing males as either females or gland extracts in cone traps (19). Additionally, only H. subflexa males were captured, while traps in the same fields baited with H. virescens or H. zea females or synthetic blends (10) also captured only conspecific males. 

To obtain attraction comparable to that of living females, the authors used about 45 mg of their mixture in polyethylene vials, which in our opinion, is an excessively high dose. We always used doses below the 1 mg level. 

Sampling. Pottery (207 pieces) was analyzed in this project. Samples varied in size from 25 to 500 mg. Individual samples were cut with a diamond saw or were broken from their parent sherd. The outer surfaces of each sample were removed with a carborundum bit. After cleaning, the samples were weighed and stored in polyethylene vials. 

For the INAA procedure, dried samples (100-600 mg) were placed in polyethylene vials and irradiated for 1-3 min in the SLOWPOKE Reactor at the University of Toronto (flux of 1011 n cm-2 s"1). The P was measured with the 31P (n, a) 28Al reaction. To measure the actual concentration of P, the same samples were irradiated a few days later under identical conditions while wrapped in cadmium foil (14). This step allowed for a correction in samples for which there was significant Al contamination. Although the INAA procedure could provide a clear indication of soil contamination, the corrections were large whenever badly contaminated soils were encountered. If soil contamination was expected, the dried bone samples were analyzed by X-ray fluorescence. The analysis was performed with a wavelength dis-... 

Sample Preparation. Copper samples weighing 100 mg were cut from larger samples using a carbide-tipped drill. These samples were cleaned in reagent-grade HCl (IN) and rinsed in triple distilled water to remove surface contaminants. Sample material was placed in polyethylene vials and thermally sealed. Four USGS standards— numbers AGV-1, BRC-1, DTS-1 and W-1— were weighed and placed in similar vials to be used as absolute standards. 

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