Infiltration effects on sediment mobility under waves

Sediment mobility measurements with a horizontal sand bed under non-breaking waves are reported. Conditions include no seepage and steady downward seepage corresponding to head gradients up to 2.5. The results indicate that infiltration tends to inhibit sediment mobility for a horizontal bcd of 0.2 mm quartz sand exposed to moderated wave induced bed shear stresses. The effect is weak for the parameter range of the present study. The two opposing effects of shear stress increase due to boundary layer thinning and the stabilizing downward drag are successfully accounted for through the modified Shields parameter of Nielsen [Nielsen, P., 1997. Coastal groundwater dynamics. Proc. Coastal Dynamics '97, Plymouth, ASCE, Dp, 546-555] using coefficients derived from independent studies. That is, from the shear stress experiments of Conley [Conley, D.C., 1993. Ventilated oscillatory boundary layers. PhD Thesis, University of California, San Diego, 74 pp.] and the slope stability experiments of Martin and Aral [Martin, C.S. and M.M. Aral, 1971. Seepage force on interfacial bed particles. J. Hydraulics Div., proc. ASCE, Vol. 97, No. Hy7, pp. 1081-1100]. (C) 2001 Elsevier Science B.V. All rights reserved.

Star factorizations of graph products

A k-star is the graph K-1,K-k. We prove a general theorem about k-star factorizations of Cayley graphs. This is used to give necessary and sufficient conditions for the existence of k-star factorizations of any power (K-q)(S) of a complete graph with prime power order q, products C-r1 x C-r2 x ... x C-rk of k cycles of arbitrary lengths, and any power (C-r)(S) of a cycle of arbitrary length. (C) 2001 John Wiley & Sons, Inc.

A servicing strategy for items sold under warranty

When repairable items sold under warranty fail, the rectification action taken by the manufacturer can be either a repair or a replacement, In this paper a new repair-replacement strategy is proposed for the manufacturer when the items are sold with a non-renewing free replacement warranty policy. The strategy involves splitting the warranty period into two intervals where only repairs are carried out, separated by a third interval with at most one replacement.

Warranty and preventative maintenance

For products sold with warranty, preventive maintenance actions by manufacturers and/or buyers have an impact on the total costs for both parties. This paper develops a framework to study preventive maintenance actions when items are sold under warranty and reviews the models that have appeared in the literature. It then develops a new model and carries out its analysis.

Facies architecture of the CRP-3 drillhole, Victoria Land Basin, Antarctica

The Cenozoic Victoria Land Basin (VLB) stratigraphic section penetrated by CRP-3 is mostly of Early Oligocene age. It contains an array of lithofacies comprising fine-grained mudrocks, interlaminated and interbedded mudrocks/sandstones, mud-rich and mud-poor sandstones, conglomerates and diametites that are together interpreted as the products of shallow marine to possibly non-marine environments of deposition, affected by the periodic advance and retreat of tidewater glaciers. This lithofacies assemblage can be readily rationalised using the facies scheme designed originally for CRP-2/2A, and published previously. The uppermost 330 metres below sea floor (mbsf) shows a cyclical arrangement of lithofacies also similar to that recognised throughout CRP-2/2A, and interpreted to reflect cyclical variations in relative sea-level driven by ice volume fluctuations ("Motif A"). Between 330 and 480 mbsf, a series of less clearly cyclical units, generally fining-upward but nonetheless incorporating a significant subset of the facies assemblage, has been identified and noted in the Initial Report as "Motif B. Below 480 mbsf, the section is arranged into a repetitive succession of fining-upward units, each of which comprises dolerite clast conglomerate at the base passing upward into relatively thick intervals of sandstones. The cycles present down 480 mbsf are defined as sequences, each interpreted to record cyclical variation of relative sea-level. The thickness distribution of sequences in CRP-3 provides some insights into the geological variables controlling sediment accumulation in the Early Oligocene section. The uppermost part of the section in CRP-3 comprises two or three thick, complete sequences that show a broadly symmetrical arrangement of lithofacies (similar to Sequences 9-11 in CRP-2/2A). This suggests a period of relatively rapid tectonic subsidence, which allowed preservation of the complete facies cycle. Below Sequence 3, however, is a considerable interval of thin, incomplete and erosionally truncated sequences (4-23), which incorporates both the remainder of Motif A sequences and all Motif B sequences recognised. The thinner and more truncated sequences suggest sediment accumulation under conditions of reduced accommodation, and given the lack of evidence for glacial conditions (see Powell et al., this volume) tends to argue for a period of reduced tectonic subsidence. The section below 480 mbsf consists of a series of fining-upward, conglomerate to sandstone intervals which cannot be readily interpreted in terms of relative sea-level change. A relatively mudrock-rich interval above the basal conglomerate/breccia (782-762 mbsf) may record initial flooding of the basin during early rift subsidence. The lithostratigraphy summarised above has been linked to seismic reflection data using depth conversion techniques (Henrys et al., this volume). The three uppermost reflectors ("o", "p" and "q") correlate to the package of thick sequences 1-3, and several deeper reflectors can also be correlated to sequence boundaries. The package of thick Sequences 1-3 shows a sheet-like cross-sectional geometry on seismic reflection lines, unlike the similar package recognised in CRP-2/2A.

Living with under-fives: a programme for parents with a mental illness

Parenthood is considered a major life role. Yet for people with a major mental illness, it is one that is fraught with difficulties and for which they receive the least support. Research on parenting and parenting programmes for people with a major mental illness is sparse and most of the papers presented do not provide a working model that can be easily replicated. This lack of support for parents or knowledge of working parenting programmes has often resulted in children being placed in care. Occupational therapists working in an Australian mental health service developed a two-stream programme which aimed to consolidate the parent/child relationship and enable the parents to develop effective parenting skills. This programme has a parents' educational stream and a stream with developmentally appropriate activities for the children. Observed outcomes have included the parents becoming more responsive to their children, increased treatment compliance, improved community access, and a decrease in the number of children in temporary foster care.

A novel method for solid-phase synthesis of oligosaccharides using the N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker

The application of the N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker for the solid-phase synthesis of oligosaccharides is described. The oligosaccharide products can be cleaved from the resin by hydrazine, ammonia or primary amines, but the linker is stable under the conditions of oligosaccharide synthesis. The first sugar can be attached to the resin linker via a vinylogous amide bond, or by ether linkage using a p-aminobenzyl alcohol converter. (C) 2001 Elsevier Science Ltd. All rights reserved.