Summary 0We examined the e}ects of nutrient availability on the competitive interactions of the New England salt marsh perennials that occupy discrete vegetational zones parallel to the shoreline[ 1 Fertilized and unfertilized plots of pair!wise mixtures and monocultures of Spartina alterni~ora\ S[ patens and Juncus`erardi were compared in order to assess the e}ects of nutrient addition on the competitive dynamics of these species in the _eld[ In addition\ we examined competition between some of these species and Distichlis spicata\ a species common to disturbed marsh habitats[

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The initiation ofdelamination in graphite/epoxy specimens was investigated both analyt ically and experimentally. Three specific laminate families were investigated: [±15 n] s, [± 15 n /0n]s, and [0n / ± 15n] s with the normalized effective ply thickness, n, varying from one to five. Delamination initiation was determined to have occurred when a drop in load was detected and a delamination was observed on a replication of the specimen edge. Measured initiation stresses were correlated using the strain energy release rate approach and the Quadratic Delamination Criterion introduced herein. The strain energy release rate approach was unable to accurately correlate data for two of the three laminate fami lies. The data clearly shows that the critical value of strain energy release rate is dependent on ply thickness. The Quadratic Delamination Criterion, an average stress criterion which compares the calculated out-of-plane interlaminar stresses to their related strength param eters, is proposed and shows excellent correlation with the delamination initiation stress data.