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Open access

Shah Md. Atiqul Haq

Abstract

The study attempts to uncover how people living in vulnerable areas address the relationship between the impacts of extreme weather events (floods) and fertility preference. The study selected a village, Sharat Pur from Sunamganj District, which is highly vulnerable to the adverse impacts of flooding. The study gathered information from 158 respondents by using a semi-structured questionnaire and in-depth interviews. With the small sample size the study used descriptive statistics and qualitative analysis. Findings show that there is still a preference for more sons to recover the damage caused from the impacts of floods. However, people think having a large family is a burden. They emphasize controlling family size through family planning programs and do not take into account the risk of children dying affecting their desire to have additional children. Therefore they consider having more children especially sons as a gift from God and the occurrence of flood events as the wish of God. The intention of the study is not to generalize findings but to comprehend the underlying mechanism between disaster events and fertility behavior. The study collected information from a very small sample size. Future studies might consider a large sample size and explore more deeply the mechanism between the different disaster events and fertility decisions by using a comparative analysis between regions vulnerable to different extreme weather events and not vulnerable to extreme weather events within Bangladesh, and comparing Bangladesh with other South Asian countries.

Open access

N R Ammar and I S Sediek

Abstract

Marine diesel engines lose a huge amount of fuel heat content in the form of exhaust gas and jacket cooling water, especially onboard high-powered marine vehicles such as Ro-Pax ships. In this paper, the possibility of using the waste heat of marine diesel engines as a source of heat for air conditioning absorption system is investigated. The thermodynamic analysis, in addition to the environmental and economic analysis of the air condition absorption cycle operated with two heat sources using lithium bromide as absorbent, are performed using the Engineering Equation Solver (EES) software. The last 10 years have seen a steady growth in the passenger ferry and Ro-Pax market, with particularly strong growth in passenger numbers. As a case study, a Ro-Pax vessel operating in the Red Sea area is considered, regarding the profitability of using air conditioning absorption system. The results show specific economic benefits of the jacket cooling water operated absorption refrigeration unit (ARU) over the exhaust gas operated unit, with annual costs of capital money recovery of 51,870 $/year and 54,836 $/year, respectively. Environmentally, applying an ARU machine during cruising will reduce fuel consumption by 104 ton/year. This, in turn, will result in reducing NOx, SOx, and CO2 emissions with cost-effectiveness of 7.73 $/kg, 20.39 $/kg, and 0.13 $/kg, respectively.

Open access

Michał Stosiak, Maciej Zawiślak and Bohdan Nishta

Abstract

The main aim of this research was to determine in three ways, i.e. experimentally, analytically and by means of numerical modelling, the resistances of the flow of a natural liquid in a helical pipe and in curved pipes. The analyses were carried out for three pipes: one helical pipe and two curved pipes. Each of the pipes was 2 m long and its inside diameter was 4 mm. The experiment was carried out on a test stand making it possible to measure the rate of the flow of the liquid, the temperature at the pipe’s inlet and outlet and the pressure at the pipe’s inlet and outlet. The resistances of the flow of the liquid were calculated from analytical or empirical formulas found in the literature on the subject. Moreover, numerical modelling was performed using the finite volume element method.

Open access

Ali Brahmia, Nafaa Brinis and Tahar Nouar

Abstract

This work was conducted on 23 samples distributed between springs, wells and boreholes tapping the shallow and deep aquifer in the M’Daourouch-Drea area located in extreme northeast of Algeria. Ca2+, Mg2+, Na+, K+, Cl, SO4 2−, HCO3 and NO3 were analysed. The interpretation of the geological-geophysical data allowed us to highlight two aquifers. The first consists of conglomerates, sandstones, gravels, sands, marls, limestones, lacustrine and alluvial deposits varying in thickness from a few tens to a few hundred meters, representing Neogene-Quaternary filling of the studied basin. The second is more important localized in the cracked and karstified limestones of upper Cretaceous age; these limestones are outcropped on the flanks of the syncline and the borders of the basin. The first aquifer sometimes rests directly on the second which allows hydraulic communication between them. The hydogeochemical and statistical study, with the combination of numerous tools, indicates that the chemistry of groundwater in the M’Daourouch-Drea Plain is controlled both by the dissolution of the minerals of the evaporite formations and those of the carbonate formations.

Open access

Yong Liu, Renxiang Bu and Xiaori Gao

Abstract

The paper reports the design and tests of the planar autopilot navigation system in the three-degree-of-freedom (3-DOF) plane (surge, sway and yaw) for a ship. The aim of the tests was to check the improved maneuverability of the ship in open waters using the improved nonlinear control algorithm, developed based on the sliding mode control theory for the ship-trajectory tracking problem of under-actuated ships with static constraints, actuator saturation, and parametric uncertainties. With the integration of the simple increment feedback control law, the dynamic control strategy was developed to fulfill the under-actuated tracking and stabilization objectives. In addition, the LOS (line of sight) guidance system was applied to control the motion path, whereas the sliding mode controller was used to emulate the rudder angle and propeller rotational speed control. Firstly, simulation tests were performed to verify the validity of the basic model and the tracking control algorithm. Subsequently, full scale maneuverability tests were done with a novel container ship, equipped with trajectory tracking control and sliding mode controller algorithm, to check the dynamic stability performance of the ship. The results of the theoretical and numerical simulation on a training ship verify the invariability and excellent robustness of the proposed controller, which: effectively eliminates system chattering, solves the problem of lateral drift of the ship, and maintains the following of the trajectory while simultaneously achieving global stability and robustness.

Open access

Jerzy Runge

Abstract

Terminology, that helps to organise research issues, is a significant component of each scientific discipline. In socio-economic geography, such expressions include concepts of a region, a city, or a social space. They are not disjunctive ideas – for example, we find a concept of an urban region where a social space can refer to a city, or a region, and at the same time regional, urban and social research can investigate these same areas. Concepts may also illustrate a specific model of an explanation in science, a particular stage of methodological development of the discipline, or a vision of the world. Bearing in mind the complexity of methodological issues, which is only briefly mentioned here, as well as a multiplicity of definitions of terminological concepts (region, city, social space), the author’s intention was to compare the premises of occurrence of the concepts and their consequences for the development of socio-economic geography. The increases in complexity of socio-economic changes as an effect of the overlapping processes of social modernization, restructuring of economic space, and suburbanization were itemised. The main research tool in this case is the deductive reasoning procedure leading to the generalization of the output of regional and urban research, as well as existing analyses of social space. The rationale for investigating the problem arose from the significance of the above-mentioned research, both the ones carried out during the previous stages of development of socio-economic geography as well as contemporary research trends. The crucial aspect here is the increase in complexity of these processes, and the spatial and functional structures leading to the transition from simple post-modernity to a risk society. Therefore, application of regional, urban and social research is also important, especially in the context of the process of depopulation, and “shrinkage” of cities and regions. It affects the possibilities of creating urban or regional policy. The rationale for investigating the problem also results from periodic necessity to synthesize the research on basic terminological issues, especially in the periods when changes of socio-economic and spatial conditions occur, and affect transformation of the existing set of the basic concepts.

Open access

Katarzyna Łuszczyńska, Małgorzata Wistuba and Ireneusz Malik

Abstract

The aim of the study was to investigate how the emission of pollutants to the atmosphere from the late 19th century until modern times has been recorded in rings of silver fir trees growing in southern Poland. Samples were collected from 24 firs growing in the Beskid Niski Mountains (Western Carpathians). Using a Pressler borer, a single core was collected from each tree. Within the samples, tree-ring widths were measured. On this basis, reductions of tree-ring widths were calculated and subsequently divided into three classes according to their severity. Study results indicate that growth reductions at the site studied were influenced by the pollution emitted from the now-defunct Central Industrial Region, which developed most rapidly from 1920 to 1940, and began to decline after World War II. These emissions were probably responsible for reductions in the trees sampled in the years 1928–1947. On the other hand, reductions of tree-ring widths dating from 1951 to 1989 were caused by the post-war development of heavy industry throughout Poland, and in particular in the Upper Silesian Industrial Region, which developed at its most rapid rate from 1960 to 1990. The results obtained demonstrate that reductions of tree-ring widths in the silver firs studied are related to industrial air pollution in the 20th century. As industrial production declined and environmentally friendly technologies were introduced in the early 1990s, air pollution levels decreased and an increase in tree-ring widths followed in the silver firs studied. Further reductions of tree-ring widths have been observed in recent years (since 2009), which may be caused by air pollution due to low-stack emissions from domestic boilers. The analysis conducted demonstrates that a reduction in tree-ring widths in silver fir is a sensitive bioindicator of air pollution.

Open access

Leszek Dawid

Abstract

At the end of 2016 there were 84 wind farms under construction in 11 European countries. Investments in this sector are enormous. The average cost of a wind farm construction amounts to approx. 4 mln EUR per 1 MW of installed power. Offshore wind energy production also plays a significant role in the process of ensuring energy security in Europe, and in reduction of greenhouse gases. The objective of this paper is to present prospects of offshore wind energy farms development in the leading member states of the European Union as regards this problem. In this paper offshore wind farms in Germany and Denmark have been studied. In the paper the power of wind farms, the support systems as well as criteria related to location of wind farm offshore have been analysed. German and Danish sectors of offshore wind energy are strongly supported by respective governments. Both countries aim at yearly increase of wind energy share in total energy production. The research has been conducted based on the analysis of acts, regulations, the subject’s literature and information from websites.

Open access

Maciej Janecki, Artur Nowicki, Alicja Kańska, Maria Golenko and Lidia Dzierzbicka-Głowacka

Abstract

Sea ice conditions in the Baltic Sea during six latest winters – 2010/2011 to 2015/2016 are analysed using coupled ice–ocean numerical model 3D CEMBS (3D Coupled Ecosystem Model of the Baltic Sea). Simulation results are compared with observations from monitoring stations, ice charts and satellite data. High correlation between model results and observations has been confirmed both in terms of spatial and temporal approach. The analysed period has a high interannual variability of ice extent, the number of ice days and ice thickness. Increasing number of relatively mild winters in the Northern Europe directly associated with climate change results in reduced ice concentration in the Baltic Sea. In this perspective, the implementation and development of the sea ice modelling approach (in addition to standard monitoring techniques) is critical to assess current state of the Baltic Sea environment and predict possible climate related changes in the ecosystem and their influence for human marine–related activities, such as fishery or transportation.

Open access

Shengke Ni, Zhengjiang Liu, Yao Cai and Xin Wang

Abstract

Ship collision-avoidance trajectory planning aims at searching for a theoretical safe-critical trajectory in accordance with COLREGs and good seamanship. In this paper, a novel optimal trajectory planning based on hybrid genetic algorithm is presented for ship collision avoidance in the open sea. The proposed formulation is established based on the theory of the Multiple Genetic Algorithm (MPGA) and Nonlinear Programming, which not only overcomes the inherent deficiency of the Genetic Algorithm (GA) for premature convergence, but also guarantees the practicality and consistency of the optimal trajectory. Meanwhile, the encounter type as well as the obligation of collision avoidance is determined according to COLREGs, which is then considered as the restricted condition for the operation of population initialization. Finally, this trajectory planning model is evaluated with a set of test cases simulating various traffic scenarios to demonstrate the feasibility and superiority of the optimal trajectory.