Response of the Black Sea mean level to atmospheric pressure and wind forcing

The response of the Black Sea mean level to atmospheric pressure (AP) and wind forcing is investigated using 5 years of TOPEX/POSEIDON (T/P hereafter) data. A coherence analysis is first applied to mean sea level and pressure to examine the validity of the inverse barometer (IB) approximation over this area. As expected, it reveals very significant deviations from an IB response attributed to the narrowness of the Bosphorus Strait and its limiting role in water exchanges. A comparison is drawn with the Mediterranean Sea case. A single basin version of the Candela analytical model [Candela, J., 1991. The Gibraltar Strait and its role in the dynamics of the Mediterranean Sea. Dyn. Atmos. Oceans 15, 267–300], which takes linear friction at the strait into account, is then used. The model explains a significant part of the T/P mean sea level variance (about 30%, while the IB correction only explains 5% of its variance) and provides a means to correct the altimeter data for the pressure effect much better than the standard IB effect. The response of the mean sea level to wind forcing is then analysed. Coherence analysis between sea level and along-strait wind stress (WS) reveals a significant coherence at periods ranging from 40 to 100 days, with an almost steady phase of 270°. This result is confirmed with a multiple coherence analysis (mean sea level vs. WS and AP). A plausible mechanism is a piling-up of water at the northern or southern end of the strait due to along-strait wind forcing. The associated along-strait pressure gradient would modify the barotropic flow in the strait and then the mean sea level. Using an extension of the Candela model, we show that this mechanism is consistent with T/P mean sea level observations.     

Modeling and analysis of a fuel-injection pump used in diesel engines

The Fuel-Injection Pump (FIP) used in diesel engine has a higher-pair cam-mechanism to pressurize the fuel for injection. This paper proposes a methodology to model FIP from a multibody Dynamics (MBD) perspective. The results from the model include the temporal behavior of driving torque, contact Hertz stress and reaction forces at various joints. The model helps the designer to assess the effect of various cam profiles, link parameters and other design variables. It is necessary that these parameters be optimized for future high pressure applications. For this purpose, a cam-mechanism with offset follower axis is analysed. Decoupled Natural Orthogonal Complement (DeNOC) matrices based algorithm is used to model FIP without and with offset cam-mechanism. The study shows that, the offset cam-mechanism allows reduction in the side-thrust, reaction forces, and the contact Hertz stress acting on the cam-follower interface. As a typical case, for an FIP working around a pressure value of 600 bar, an optimum offset value is found to be 9.5 mm and it shows a reduction of about 45% in side thrust values. To validate the modeling approach, experimental studies are performed on pump without and with offset cam-mechanism. Experimental results are in qualitative agreement with the theoretical model results.     

The authors in this issue

This paper analyses the impacts on a particular region of a recent policy change regarding public transit subsidy in New Zealand, under which the contributions of local authorities are increased from 0 to 50% of net direct expenditures. The options open to the community are examined and their effects on regional income, future development and social equitability are analysed. It also illustrates the cost effectiveness of a natural monopoly under increased accountability.     

Sociocultural Effects of a Market-Based Fishery Management Program in the Florida Keys

Spiny lobster (Panulirus argus) represents one of the most lucrative fisheries in the State of Florida, and a majority of the catch is landed in the Florida Keys. Over the past three decades, the industry grew significantly, and by the end of the 1980s, state fishery managers agreed that the fishery was overextended. In 1991, the Florida Legislature passed the Spiny Lobster Trap Certificate Program (LTC), created to stabilize the industry by reducing the total number of traps while allowing fishers to transfer trap certificates in a market-based system akin to individual transferable quotas. Data from a survey study suggest that a majority of the respondents are dissatisfied with the LTC, which they view as transitory and unsustainable. The fishers' negative views are motivated by sociocultural changes in the fishing community. Managers need to consider modifications to the LTC and other such marketbased programs to minimize sociocultural impacts and retain small-scale fisher participation in such fisheries.     

The Trial Intensive Management Area for Crocodiles: A Crocodile Removal Zone in Queensland,Australia

The Estuarine Crocodile (Crocodylus porosus) is the world's largest living crocodile, and in Queensland it inhabits tropical coastal wetlands and waterways. From 1990 to 2001, there have been nine substantiated crocodile attacks on people in Queensland, resulting in one death and eight serious injuries. Several crocodile attacks occurred in the Cairns area during these years, and Cairns's popular swimming beaches have been closed on a number of occasions because of crocodiles. Human safety from crocodile attack is an issue of great public and political concern in Queensland. From May 1998 to June 2001, the Queensland Parks and Wildlife Service operated a trial crocodile removal program in the Cairns area, with a removal zone that extended 70 km along the coast. The program was named the Trial Intensive Management Area for Crocodiles (TIMAC), and its primary purpose was to protect the Cairns's popular swimming beaches from crocodiles. The program was expanded to provide a problem crocodile response service throughout north Queensland and to train additional rangers in crocodile management skills. During the three years of the TIMAC program, 80 crocodiles were captured in north Queensland: 46 crocodiles from within the removal zone, and 34 from outside the removal zone. There were no crocodile attacks in the removal zone during the three-year trial program. At the request of local governments, the program became permanent in July 2001. In effect, Cairns is the only tropical city whose popular swimming beaches are protected by a combination of a lifeguard service, a shark control program, netted enclosures (seasonal) for protection from dangerous Box Jellyfish (Chironex fleckeri), and a crocodile removal program.     

Short time-scale analysis of the NW Mediterranean ecosystem during summer–autumn transition: A 1D modelling approach

Modelling was used as a tool to better understand the physical and biological processes observed during the multidisciplinary cruise DYNAPROC 2 (DYNAmic of rapid PROCesses in the water column), which took place in the Ligurian Sea in September–October 2004. The aim of the cruise was to study the short time-scale physical and biological processes that occur when the ecosystem switches from summer oligotrophy to autumnal mesotrophy. In this study, we have tested two 1D physical–biological coupled models. The first was a classical model in which surface layer dynamics were obtained using the turbulent kinetic energy model of Gaspar [Gaspar et al., 1990]. The simulated food-web took into account ten state variables: three nutrients, three classes of phytoplankton, two classes of zooplankton and two types of detritus. The second model (called IDA, Isopycnals Depth Adjustment) was based on the initial one but it took into account the measured variations of isopycnals depths. The results showed that the IDA model most efficiently reproduced the observed ecosystem dynamics. We have therefore used the IDA model to show that physical processes observed during the cruise had a major effect on biological compartment, mainly on nano- and picophytoplankton.     

Suitability of Decision-Theoretic Models to Public Policy Issues Concerning the Provision of Shoreline Stabilization and Hazard Management

This article examines the suitability and potential advances of decision-theoretic models from finance regarding investment decisions in shoreline stabilization projects. A set of scenarios represents the dynamics of the decision-state facing the planner and identifies factors that should be incorporated into the decision-making process. It is shown that decision models from finance can account for the risk and uncertainty inherent in shoreline stabilization projects, potentially suggest improvements and refinements to presently used cost-benefit analysis procedures, and offer new tools that can aid in decisions concerning provision of shoreline stabilization. The outcomes of these scenarios justify better planning and control of existing and future building, and that of poststorm policies. Lastly, these models allow us to explore the range of our understanding of coastal processes and interactions with shoreline stabilization projects and can identify new and useful data needed in coastal management and hazard management decisions.     

Changing patterns of urban travel Part 2. public transport and future patterns of travel

This two‐part paper contains most of a report prepared by TRRL for the European Conference of Ministers of Transport, and presented by one of the authors to the Council of Ministers in November 1984. Part 1, which was published in the January‐March 1986 issue of Transport Reviews, looked at the way cities have been changing over the years and the influence of growing car ownership on trip patterns. This part examines the changes in public transport use in more detail, considers the interactions between the various underlying trends, speculates on future travel patterns by both public and private means and considers the likely impact of land use and transport policies.     

De l’intérêt de contrôler l’impact des hypothèses de composition du parc automobile sur l’estimation des émissions liées au trafic routier

Since the 1990s, transport project assessments take systematically pollutant emission estimations into account. This paper is about the methodological aspects of these calculations. It focuses more specifically on the car fleet hypothesis, which most often lays on national data, without consideration of local specificities. We use the last household travel survey from Lyon, 2006, and the SIMBAD model to compare the results of CO₂ and NO_x emissions estimated from the French national car fleet, the aggregated Lyon car fleet and the same fleet disaggregated by household location and income. We show that the error level varies, depending on the pollutant and the observation scale. The use of an aggregated local car fleet seems interesting and satisfactory for a global emission assessment. If the results are required at a more detailed spatial level, the use of this local fleet improves sharply the estimations in comparison of a national fleet; the fleet disaggregation refines the results for NO_x.