Some economic aspects of conflicts over land use in the coastal zone

Abstract

Recent land use legislation pays particular attention to the coastal zone where age‐old conflicts have recently accelerated. Flexibility is required in policy because visible conflicts are tied into complex physical and social systems which may require changing patterns of land use over time. Public policy is altering property rights and a thorough understanding of the economic and social roles played by those rights is required. Economic models can be used to understand some major changes such as types of alteration of the environment, but may be ignored or misused unless a better understanding of coastal decision processes is developed.     

A user‐resource planning framework for offshore recreational artificial reefs

Abstract

Artificial reefs have been used extensively in coastal waters to attract and enhance recreational fishery resources. In the United States, they have been traditionally built from “materials of opportunity”; using limited budgets. This paper explores some past planning philosophies and presents a recent artificial reef deployment case that demonstrates a lack of sensitivity to local and regional recreational demand. A systems framework is developed to guide future planning efforts in artificial reef development. The framework is intended to integrate previously fragmented knowledge and to demonstrate the interdisciplinary nature of artificial reef planning. Emphasis is given to advance planning, user dimensions, and the integral issue of reef access.     

Shipper's councils: role and responsibility—a western view

This paper first presents arguments for having public sector port authorities. They can deal, flexibly and permanently, with property rights within their own areas. They can plan and regulate port areas comprehensively. They can provide ‘public goods’. They can deal, in various ways, with externalities. They can promote efficiency, whether their own (if they operate as a comprehensive port) or that of the private sector (if they are largely landlords). For example, if their policy is to rely on the private sector to produce efficiency through competition then they can see to it that there actually is competition and not any kind of cartel or monopoly. Examples are cited where this last function has not been performed. The exception for single-user ports is noted.

Against them are the general disadvantages of public authorities (or bureaucracies)—though examples are cited where port authorities had very small staffs. The common instances of ‘market failure’ may thus be contrasted with those of ‘government failure’. Finally, a pragmatic approach is advocated, tailored to the needs and resources of the country in question. The increasing effect of the economies of scale in port technology, and its limitation on competition, is, however, noted and to be discussed in the next paper.     

Influence of seabed sand wave on hydrodynamic performance of submersible北大核心CSCD

[目的]研究潜器在海底沙波地形干扰下的水动力特性。[方法]基于计算流体力学(CFD)方法,使用STAR-CCM+软件并结合重叠网格方法对潜器经过海底沙波的过程进行模拟,计算潜器阻力系数和升力系数在此过程中的变化。[结果]结果表明,当潜器近海底航行时,沙波地形会对潜器产生一定的干扰,当艏部运动至波峰附近时,负升力出现最大值,当艉部运动至波峰附近时,阻力出现最大值;在不同航速下,潜器表面压力分布规律的不同会导致升力系数的变化规律不同;随着近海底距离的减小,海底沙波对潜器阻力和升力变化影响显著,当H/D>5时,海底沙波对潜器阻力和升力的影响可以忽略。[结论]所做研究可为潜器的安全及操纵性能提供一定的参考。     

Response of carbon fiber trapezoidal corrugated sandwich structure under air explosion loading北大核心CSCD

The effects of the thickness of the face plate, angle of the wall plate and height of the core layer on the anti-explosion performance of carbon fiber reinforced composite trapezoidal corrugated sandwich structures were investigated. [Methods]First, based on the 3D Hashin failure criterion, a subroutine module of the damage evolution of fiber reinforced composites is developed using the VUMAT user subroutine interface in ABAQUS. Second, through comparison with experiments in the public literature, the effectiveness of the dynamic response simulation method of carbon fiber reinforced composites based on a development subroutine under explosion impact loading is verified. Finally, a parametric study on the explosion resistance of carbon fiber reinforced composite trapezoidal corrugated plates is carried out based on the numerical method. [Results]The results show that, compared with increasing the thickness of the blast face panel, increasing the thickness of the back blast face panel can improve the explosion resistance of the sandwich plate more obviously; when the folding angle of the core wall plate decreases from 45° to 30°, the explosion resistance increases by 1.3%; when it decreases from 60° to 45°, the explosion resistance increases by 6.3%; and whenthecoreheightincreasesfrom8mmto20mm, theexplosionresistanceincreasesby27.7%.[Conclusions]The results of this study can provide references for the explosion-proof design of carbon fiber reinforced composite sandwich structures. © 2023 Journal of Nanjing Agricultural University. All rights reserved.     

双通线加热的热力学及实验分析(英文)

The present investigation deals with process analysis of oxy-acetylene flame assisted double pass line heating for varying plate thickness. oxy-acetylene flame as the heat source for multi pass line heating to achieve 3-D bending of plates with varying thicknesses was studied. The oxy-acetylene flame was modeled as the moving heat source in the FEM analysis. The transient thermal histories were predicted taking into account the temperature dependent thermo-mechanical properties. A comparative study between single pass and double pass line heating residual deformation was also carried out. The temperature distribution and residual deformations predicted by the numerical model developed in the present work compared fairly well with those of the experimental ones.     

Estimation of wave-induced ship hull bending moment from ship motion measurements

A time-domain technique for estimating wave-induced ship hull bending moment from ship motion measurements is presented. This technique is developed to improve hull response monitoring systems. Artificial neural networks are used to model the time-domain relationship between the wave-induced vertical bending moment and the coupled heave and pitch motions. The application of the proposed technique is validated using experimental data.     

Transport infrastructure provision and operations: Why should governments choose private–public partnership?

Recent transport sector liberalisation, as well as global economic crisis, is favouring the implementation of transport infrastructure projects through Public–Private Partnerships (PPP). However, there is a debate as to whether PPP schemes are a better option than conventional procurement. To this end, an evaluation framework is proposed, to assess which of these two alternative schemes for transport projects financing is preferable for the public. The proposed framework is complimentary to the Value for Money (VfM) approach and is based on a Multi Criteria Analysis (MCA). The first step is the estimation of the Public Sector Comparator (PSC) for the case of conventional procurement, dealing with construction, maintenance and operation costs revenues, as well as any costs associated with risks undertaken by the public. As for the PPP case, it includes any payments by the public sector and related risks costs. The MCA is then applied only if the PPP is found preferable for the public sector. The latter considers additional impacts, including among others the social attributes of a particular scheme, job creation, environmental impacts and safety and security aspects. The proposed framework was applied to a pilot Bus Rapid Transit (BRT) corridor infrastructure project in the city of Indore, India, in order to demonstrate its validity. The framework and its application could provide useful guidance when considering PPP for a transport project, since it demonstrates in a transparent way the society's attitude towards this project, something that is critical to its acceptance.