A systemic review of shipboard SCR installations in practice

Growing customer demands and more stringent regulations to reduce harmful air emissions from ships have resulted in an increased interest for the installation of shipboard abatement technologies. Specifically, the selective catalytic reduction (SCR) technology to reduce emissions of nitrogen oxides (NO_x) was early adopted by several Swedish shipping companies. The potential NO_x reduction efficiency of the SCR is well established, but the practical experiences of shipboard installations have been less documented. This paper reviews from a systems perspective the practical experiences of marine SCR installations in Swedish shipping. The aim is to identify important not only technical but also human and organizational conditions necessary for safe, efficient, and sustainable SCR operations at sea. Further, to investigate to what extent the capabilities and limitations of human operators and maintainers are taken into account in the design and installation phase of the systems. Two focus group interviews (n?=?10) and five individual interviews were held with relevant stakeholders in the industry, following a semi-structured schedule on the themes installation, operation, maintenance, and training. The results show that deficiencies in the overall system design—with a combination of technical issues, maintenance access problems, and untrained operators with inadequate understanding of the SCR process—have led to inefficient, costly, and unsafe operations. It is concluded that installations and operations of marine SCR systems, and possibly other forthcoming abatement technologies, would benefit from the use of traditional ergonomic principles and methods. This would in turn contribute towards increased sustainability and a reduced environmental impact from shipping.     

An analysis and comparison of multinational officers of the watch in the global maritime labor market

ABSTRACT

Officer of the watch (OOW) is an important part of the maritime labor market. For many years, countries have been improving their development of OOWs for the maritime market, in terms of both quantity and quality. As the supply of qualified OOWs for maritime transportation is such an important issue, shipping companies recruit multinational OOWs for both economic and socio-cultural reasons. This study aims to identify the qualifications of an ideal officer that holds office on commercial ships, and to make a comparison among Filipino, Chinese, Indian, Eastern European and Turkish OOWs. The research takes into account expert opinions of a number of shipping companies that employ multinational seafarers. A Fuzzy Analytic Hierarchy Process (FAHP) technique is applied in this study to assist in the comparison of officers. A number of main and sub-criteria are outlined to determine both positive and negative aspects of OOWs from the selected countries for decision making purposes. This study allows maritime countries to evaluate their maritime education and training policies for selection and assessment of OOWs.     

Administrative burdens and over-exertion in Swedish short sea shipping

ABSTRACT

Despite significant changes in work tasks performed on board, towards more sedentary monitoring and administrative work, the incidence of occupational injuries and disorders remains high among seafarers. In order to improve safety standards, industry stakeholders increasingly require written documentation of numerous routines, procedures and tasks performed on board. These increased demands have however added to the administrative burden. Some say, to the extent that administrative work has become a safety risk in itself. This paper presents the result of a survey investigating how Swedish seafarers perceive their own level of fatigue, stress and over-exertion related to work. The material consists of 1309 respondents originating from a random selection procedure, of which 651 reported to be employed in short sea shipping. Multiple regression analysis (OLS regression), allowing adjusted effects, were applied in several steps of the analysis. The highest levels of exertion were reported by employees in the catering department, positions not generally associated with high administrative burden. Perceived high levels of administrative work do increase the level of exertion, but cannot explain the observed pattern. Future ship and trade-specific studies on physical and mental well-being and complementary studies on the catering department’s working conditions and work environment are necessary.     

Technology analysis and low-cost design of automotive radar for adaptive cruise control system

Recently, the advanced driver assistance system (ADAS), which helps mitigate car accidents, has been developed using environmental detection sensors, such as long and short range radar, lidar, wide dynamic range cameras, ultrasonic sensors and laser scanners. Among these detection sensors, radars can quickly provide drivers with reliable information about the velocity, distance and direction of a target obstacle, as well as information about the vehicle in changing weather conditions. In the adaptive cruise control system (ACCS), three radar sensors are usually needed because two short range radars are used to detect objects in the adjacent lane and one long range radar is used to detect objects in-path. In this paper, low-cost radar based on a single sensor, which can detect objects in both the adjacent lane and in-path, is proposed for use in the ACCS. Before designing the proposed radar, we analyzed the world-wide radar technology and market trends for ACCS. Based on this analysis, we designed a novel radar sensor for the ACCS using radar components, such as an antenna, transceiver module, transceiver control module and signal processing algorithm. Finally, target detection experiments were conducted. In the experimental results, the proposed single radar can successfully complete the detection required for the ACCS. In the conclusion, the perspective and issues in the future development of the ACCS radar are described.     

The comparison of general cargo ship economic performance by simulation

Cargo ship designs offered by shipbuilders differ in characteristics such as deadweight, speed, fuel consumption and cargo equipment. The best vessel for high freight markets and high fuel prices may not be the best for low freight markets and low fuel prices. A model has been developed to compare by simulation a number of multi-purpose general cargo vessels suitable for the trade of a Turkish shipowner. The model simulates the operation of each vessel under a variety of operating scenarios, e.g. fuel prices and freight profiles over the ships' lives, and estimates the distribution of resulting net present values. The techno-economic simulation model incorporates variables including ship size, speed, first cost, fuel consumption, load factor and port days.

Results are presented for six standard vessels of around 20 000 dwt operating over a long and a short route. Although the ranking of the six varies with assumptions, one design is shown to be superior under most operating conditions.     

速度至230 km/h的有源调节受电弓的运行试验

用有源调节受电弓在Re 200型接触网下以最高230 km/h的速度试行.开发这种受电弓的目的是,在现有的接触网下能以高于设计速度运行;降低弓/网的磨损,增加其使用时间;降低高速时的噪声.     

Validation of railway vehicle dynamic models in training simulators

Training simulators play an important role for sustaining safety, efficiency and cost effective railway transportation. Dynamic modelling of train systems is one of the main modules of training simulators. Validation of the dynamic models with collected real data ensures the fidelity of the simulator utilising the respective models. In this study, a validation process (Dynamic Modelling Validation Process (DyMVaP)) which is developed to support the validation of railway dynamic models is introduced. However, the proposed process can also be used in validating other dynamic models as well. The developed process is based on five steps including the preparation of validation scenarios, sensor deployment, real data collection, data preparation, and comparison of simulated and measured data. Note that the proposed DyMVaP was used for the validation of a full-mission training simulator so called TRENSIM, which was developed for Turkish State Railways. During the study it is realised that the current speed, travelled distance, acceleration (in x, y, z directions), rotation angles (around x, y, z axes), air pressure, in-train pressure/tension forces, traction motor currents, catenary voltage, positions of controllers must be collected synchronously by using proper sensors in order to ensure simulation validation. The required data was collected from locomotive body, bogies, wheel sets and connection of railway cars. The data (～200?GB) collected from the field by applying 27 different scenarios and transformed into appropriate data for utilising the generated dynamic models within the simulator. The measured and simulated data were also compared visually using graphical representation of the parameters as well as performing computations regarding the magnitude, phase and comprehensive error factors.     

The limits of analyzing service quality data in public transport

In recent years, management and academics have increasingly focused on quality management in public transport. In particular, many public transport operators regularly monitor their service quality over time and use these data to assess quality performance (e.g., for performance-based quality contracts) and to determine managerial decisions (e.g., budget allocations for service improvements). However, despite the widespread applications of service quality data in practice, it is unclear whether cross-sectional analyses and cross-temporal comparisons of service quality data provide valid insights for quality management purposes. In this study, we investigate the usability of cross-sectional analyses and cross-temporal comparisons of service quality data by conducting an empirical study that tracked a panel’s perceptions of the service quality of public transport and its choice over the course of three consecutive years. The results demonstrate that cross-sectional analyses provide valid insights for quality management. However, cross-temporal comparisons should be interpreted carefully because the results of these comparisons are surprisingly unreliable. In fact, we find that service quality data do not provide reliable results over time and therefore conclude that cross-temporal comparisons of service quality data must be interpreted with caution for quality management in public transport.     

轻轨车辆噪声评价标准初探

根据轻轨车辆噪声的现状及特点,本文认为轻轨车辆的噪声仍以A声级评价为宜,但需规定容许的倍频程带声压值,以抑制低频噪声对人体的影响,同时提出了轻轨车辆噪声的控制标准。最后还指出了A声级评价总体的缺陷,建议应以人体工程学为基础,综合考虑噪声对人体的多方面危害,以制定出更完善的轻轨车辆噪声评价标准。     

Investigation of soot formation in Diesel-GTL fuel blends under quiescent conditions

In this study, a visual investigation of sprays and flames is performed, and soot formation in Diesel-GTL fuel blends is studied in a specially designed quiescent constant-volume chamber under various ambient gas temperatures and O₂ concentrations. Similar to the case of soot formation during diesel fuel combustion, the sooting zone during the mixing-controlled combustion of Diesel-GTL blends is located in the leading portion of the jet boundaries. Auto-ignition delay and soot concentration decrease with an increase of GTL content in the fuel blend. Soot also decreases with lower O₂ concentration, higher injection pressure, and lower ambient gas temperature. The lack of soot formation at lower O₂ concentrations and lower temperatures suggests that Diesel-GTL fuel blends can be successfully utilized in low-temperature diesel combustion technologies that are currently being developed. Furthermore, this mixing controlled combustion method with Diesel-GTL blends can be used to modulate various engine operation parameters, and therefore to simultaneously reduce the formation of soot and NOx within a wide range of diesel engine loads.