An analytical model for bore-driven run-up

We use a hodograph transformation and a boundary integral method to derive a new analytical solution to the shallow-water equations describing bore-generated run-up on a plane beach. This analytical solution differs from the classical Shen-Meyer runup solution in giving significantly deeper and less asymmetric swash flows, and also by predicting the inception of a secondary bore in both the backwash and the uprush in long surf. We suggest that this solution provides a significantly improved model for flows including swash events and the run-up following breaking tsunamis

Vertical scales and shear stresses in wave boundary layers over movable beds

Unified scaling rules are provided for smooth and rough wave boundary layers. It is shown that the rough equivalent of the smooth, or viscous, vertical scale √2v/ω, the Stokes' length, is √0.008rA, where r is the Nikuradse roughness and A is the near-bed semi excursion of the wave motion. Realizing this equivalence of viscous and rough scales a unified description in the style of Colebrook's (1939) formulae for steady flow friction can be devised based on the unified vertical scale z = √2v/ω + √0.008rA. That is, unified smooth and rough wave friction factor formulae in the form f = f (z1/A) = f ([√2v/ω + √0.008rA ]/A) can be used with adequate accuracy. A general procedure is given for deriving z1 from velocity data including data from mobile bed experiments, which enable determination of the equivalent Nikuradse roughness from these experiments. Presently available sheet flow data show a velocity structure, which corresponds to a Nikuradse roughness r of the order 50 to 100 grain diameters. Instantaneous shear stresses τ(z,t) derived through the usual momentum integral from sheet flow experiments show that T varies strongly through the sheet flow layer with the value at the lowest level of sediment motion being 2 to 3 times the value at the undisturbed bed level. The corresponding Nikuradse roughnesses are about 2.5d corresponding to the undisturbed bed level and 100d 0 for the stress at the lowest level of sediment motion. With this strong variation of r through the layer of moving sediment, it is not at all obvious what should be understood by THE BED SHEAR STRESS in the context of wave sediment transport

Ozone measurement systems improvements studies

Results are summarized of an initial study of techniques for measuring atmospheric ozone, carried out as the first phase of a program to improve ozone measurement techniques. The study concentrated on two measurement systems, the electro chemical cell (ECC) ozonesonde and the Dobson ozone spectrophotometer, and consisted of two tasks. The first task consisted of error modeling and system error analysis of the two measurement systems. Under the second task a Monte-Carlo model of the Dobson ozone measurement technique was developed and programmed for computer operation

General solutions for the initial run-up of a breaking tsunami front

An assessment of potential damage on coastlines due to tsunami requires prediction of the likely flow depths and impact forces on structures. Since tsunami have a long wavelength relative to the water depth, models that solve the non-linear shallow water equations (NLSWE) are appropriate. Carrier et al (2003) presented solutions for tsunami that do not break. However, where the leading front of the tsunami breaks, the wave front is more similar to a bore approaching the shoreline. An analytical treatment for the run-up driven by an incident bore was developed by Shen & Meyer (1963). However, the Shen & Meyer result is only unique close to the shoreline, and the flow depths and velocities depend on the seaward boundary condition. Here, a new numerical model is presented that solves the NLSWE for the case of a broken tsunami front arriving at the shoreline. It is a simple model that allows specification of either the flow depths or velocities at the seaward boundary, and the solution method allows the effects of friction to be incorporated. The model is able to reproduce the Shen & Meyer analytical solution for the initial motion of the shoreline. The potential damage to coastal structures and other infrastructure may be assessed by calculation of impact and drag forces due to the predicted flow depths and velocities

An introduction to spacecraft thermal control

External and internal passive and active methods for spacecraft thermal control - material insulation and structural propertie

Perubahan Struktural Dalam Pembangunan Perkotaan

Pertumbuhan daerah kota di negra berkembang menunjukan gejala yang tidak di harapkan.untuk mengantisipasi kondisi keterbelakangan ini, daerah perkotaan haurus di dorong secara kuat untuk meningkatkan permintaan terhadap barang dan pelayanan untuk seluruh kepentingan nasional. permasalahan kota yang telah di hadapi bukan hanya persoalan keruangan dan Perubahan struktur ekonomi saja, tapi juga pembentukan implikasi sosial dan lingkungan. hal ini dapat di lihat di Bogota dengan pola dualisme sistem sosialnya, adanya pemisahan ruang antara masyarakat kaya di daerah utara dan masyarakat miskin di daerah selatan dan barat. Fenomena serupa juga di temukan di Indonesia. Jakarta yang berkembang secara cepat dengan dukungan sektor manufaktur dan keuanga, mencapai kondisi ekonomi dan pendapatan yang baik. Bagaimanapun, di Balik kondisi tersebut, ditemukan biaya yang tak terhindarkan secara nyata, yang umum muncul berupa penurunan kualitas lingkungan. Beberapa kebijaksanaan direkomendasikan adalah: (1) Meningkatkan produktivitas ekonomi wilayah kota yang terintegrasi ke dalam pembangunan regional dan pedesaan, (2) Meningkatkan produktivitas kelompok miskin perkotaan melalui perbaikan infrastruktur sosial dan perluasan kesempatan kerja, (3) Menghindari Perusakan lingkungan serta konsekwensi lainnya di sekitar wilayah masyarakat miskin, dan (4) Membangun persepsi yang seimbang terhadap pembangunan kota dan permasalahan-permasalahan yang berkaitan dengannya: pemerintah, sektor swasta, dan masyarakat

Modelling tsunami inundation on coastlines with characteristic form

This paper provides an indication of the likely difference in tsunami amplification and dissipation between different characteristic coastal embayments, coastal entrances and estuaries. Numerical modeling is performed with the ANU/Geoscience Australia tsunami inundation model. Characteristic coastal morphology is represented by simpler generic morphological shapes which can be applied easily in the ANUGA model, such that key non-dimensional parameters (e.g. embayment depth/bay width) can be varied. Modeling is performed with a range of bay shapes, seabed gradient and different incident tsunami wave shapes and wave angles, including sine waves, solitary waves and leading depression Nwaves. The results show a complex pattern for both large and small embayments, with wave breaking an important control on the amplification of the wave between the 20m contour and the shore. For large embayments, the wave run-up can be amplified by a factor six in comparison to the amplitude at the model boundary. For small embayments, the amplification is dependent on the location of the ocean water line, or tidal stage

In Vitro Behavior and UV response of melanocytes derived from carriers of CDKN2A mutations and MC1R variants.

Co-inheritance of germline mutation in cyclin-dependent kinase inhibitor 2A (CDKN2A) and loss-of-function (LOF) melanocortin 1 receptor (MC1R) variants is clinically associated with exaggerated risk for melanoma. To understand the combined impact of these mutations, we established and tested primary human melanocyte cultures from different CDKN2A mutation carriers, expressing either wild-type MC1R or MC1R LOF variant(s). These cultures expressed the CDKN2A product p16 (INK4A) and functional MC1R. Except for 32ins24 mutant melanocytes, the remaining cultures showed no detectable aberrations in proliferation or capacity for replicative senescence. Additionally, the latter cultures responded normally to ultraviolet radiation (UV) by cell cycle arrest, JNK, p38, and p53 activation, hydrogen peroxide generation, and repair of DNA photoproducts. We propose that malignant transformation of melanocytes expressing CDKN2A mutation and MC1R LOF allele(s) requires acquisition of somatic mutations facilitated by MC1R genotype or aberrant microenvironment due to CDKN2A mutation in keratinocytes and fibroblasts. This article is protected by copyright. All rights reserved