Evaluating Penetration Ability of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) Larvae into Multilayer Polypropylene Packages
The larvae of the Indian meal moth, Plodia interpunctella (Hübner), can invade or penetrate packaging materials and infest food products. Energy bars with three polypropylene packaging types were challenged with eggs (first instars), third instars, and fifth instars of P. interpunctella to determine package resistance at 28 °C and 65% r.h. The packing types were also challenged with two male and two female pupae of P. interpunctella under similar conditions in order to determine which package provided the greatest protection against larval penetration. Samples infested with eggs, third instars, and pupae were evaluated after 21 days and 42 days to count the number of larvae, pupae, and adults found inside the packages. Packages challenged with fifth instars were observed after 21 days to count the number of larvae, pupae, and adults inside each package. The number and diameter of the holes were determined in each package, followed by the amount of damage sustained to the energy bar. Third and fifth instars showed a higher tendency to penetrate all of the packaging types. First instars showed a reduction in package penetration ability compared with third and fifth instars. The increase in exposure time resulted in an increase in the damage sustained to the energy bars. Among packaging types, the thickest package (Test A) was most resilient to penetration by all of the larval stages. In conclusion, energy bar manufacturers need to invest more effort into improving packaging designs, creating thicker gauge films, or advancing odor barrier technology, in order to prevent penetration and infestation by P. interpunctella larvae.
Penetration of Seven Common Flexible Packaging Materials by Larvae and Adults of Eleven Species of Stored-Product Insects
The ability of larvae to penetrate flexible packaging materials was determined for large and small larvae of 11 species of stored-product insects. These insects were confined individually, with or without food, in small pouches made of cellophane, polyethylene, paper, polyvinylchloride, aluminum foil, polyester, or polypropylene.

Larvae of Oryzaephilus mercator (Fauvel), Cathartus quadricollis (Guerin-Meneville), and Cryptolestes pusillus (Schonherr) made no penetrations. Tribolium castaneum (Herbst) larvae were very weak penetrators. Only Tenebroides mauritanicus (L.) and Trogoderma variabile Ballion larvae penetrated all 7 materials. Larvae of the 5 other species, Dermestes maculatus De Geer, Lasioderma serricorne (F.), Ephestia cautella (Walker), Corcyra cephalonica (Stainton), and Plodia interpunctella (Hubner), penetrated 5 of the 7 materials. Foil, polyester, and polypropylene were generally the most resistant to penetration.

Larvae of all species generally showed a much greater propensity to penetrate when confined without food. Many penetrations occurred within 24 h and most occurred within 1 wk. Some larvae that did not penetrate and subsequently transformed into adults made more penetrations as adults than as larvae.

The locations of the penetrations in the vertically positioned pouches were predominantly in the bottom 1/2 of the pouches and in a zone 0–1 cm from the folds.
Comparison between Two Chemicals for Reducing Scale Formation in Reverse Osmosis Systems
In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25)l/h, pH of the feed solution (6-10) on the recovery ,penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor ,zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8)mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation ,while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors .It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.