This paper identifies the adverse events occurring during the execution of water supply and sewerage systems construction. The basis for this paper is research conducted in 2010-2014 on the construction sites of water supply and sewerage systems located in the provinces of Lower Silesia and Opole. The research consisted of direct observations of construction sites and review of construction documentation. It showed that work stoppages on the examined construction sites were frequent. They were caused by violations of work discipline by the production employees, adverse weather conditions, and defects in the project documentation. The study demonstrated that in almost every case, these bad an adverse effect on the completion date and budget of the investment. The analyses show that in such important and expensive investments as water supply and sewerage systems, organizational structures in which a special role is assigned to middle-rank personnel should be adopted.

The issue of transportation is a particular type of mathematical programming that facilitates searching for and determining an optimal distribution network, considering the set of suppliers and recipients. This paper uses a numerical example to present a solution to a transport problem utilizing classical computation methods, i.e., the northwest corner, the least cost in a matrix, and the VAM approximation method. The objective of the paper was to develop tools in the form of algorithms that would then be implemented in three various computing environments (R, GNU Octave, and Matlab) that allow us to optimize transport costs within an assumed supply network. The model involved determining decision variables and indicating limiting conditions. Furthermore, the authors interpreted and visualized the obtained results. The implementation of the proposed solution enables users to determine an optimal transport plan for individually defined criteria.

The scope of the paper refers to long- and medium-run trends of labour supply in Poland. The main purpose is to determine current trends in the labour supply and its projections till the year 2050. In the theoretical part of the paper determinants of labour supply are considered. The projections are based on the population forecasts till 2050 made by the Central Statistical Office of Poland (CSO) and by the authors’ own simulations. Several variants of upper limit of working age and activity rates are taken into account. The population forecasts by the CSO indicate it will occur big decrease of working age population till 2050. The biggest decrease will refer to the group of working age 18–59/64 years and the lowest decrease in the age group 18–66 years. The analysis shows that the declines in labour supply in the years 2020–2050 will occur in all variants of working age population, the biggest decline in the variant assuming the age group 18–59/64 and the smallest decline – in the group 15–74 years. Retirement age is of big importance for the size of labour supply. This is why it is recommended to encourage older people to prolong their economic activity. It is also necessary to increase activity rates in the working age population.

The evaporation temperature is regarded as one of the major parameters influencing the organic Rankine cycle (ORC) efficiency. Majority of contributions in literature for ORC cycle analyses treat the heat source as if it had an infinite heat capacity. Such analyses are not valuable as the resulting temperature drops of the heat source needs to be small. That leads to the fact that the heat source is not well explored and in the case of waste heat utilization it can prove the poor economics of the ORC. In the present study cooperation of the ORC cycle with the heat source available as a single phase or phase changing fluids is considered. The analytical heat balance models have been developed, which enable in a simple way calculation of heating fluid temperature variation as well as the ratio of flow rates of heating and working fluids in ORC cycle. The developed analytical expressions enable also calculation of the outlet temperature of the heating fluid.

Industry 4.0 will affect the complexity of supply chain networks. It will be necessary to

adapt more and more to the customer and respond within a time interval that is willing

to accept the product waiting. From these considerations, there is a need for a different way

of managing the supply chain. The traditional concept of supply chain as a linear system,

which allows optimizing individual subsystems, thus obtaining an optimized supply chain, is

not enough. The article deals with the issue of supply chain management reflecting demand

behaviour using the methodology Demand Driven MRP system. The aim of the publication

is to extend the knowledge base in the area of demand-driven supply logistics in the

A 6 km long stretch of the coast of Calypsostranda between Skilvika and Josephbukta, situated on the western side of Recherchefjorden, was investigated. It is made of an accumulative marine terrace at a height of 2–8 m a.s.l. (terrace 1) and width of 40–180 m, divided by a cliffed section in the frontal moraines of Renardbreen. From the character and intensity of changes, the area was divided into 6 zones. The aim was to analyse the dynamics of changes within coastal zone from 1936 to 2007 and to characterise the influence of various morphogenetic factors (marine, fluvial, cryospheric). The important element of this study has been to determine sources and directions of sediment transport. The dynamics of changes of coastal zone in the Calypsostranda region was established from archival maps and precise GPS measurements for the periods: 1936–1960, 1960–1990, 1990–2000, 2000–2005, 2005–2006, 2006–2007. Comparing the extension of shoreline between 1936 and 2007 showed that there was more erosion than accumulation. Nearly 110 000 m 2 of the area of terrace 1 decreased, whereas about 77 000 m 2 appeared. The net balance for 1936–2007 was about −32 700 m 2 , on average over the whole length of the shoreline, it re − treated by 5.7 m (0.08 m a −1 ). The cease of sediment delivery in the extramarginal sandur fans area of Renardbreen caused intensification of marine processes, that made the shore − line retreat by over 100 m. Continuing sediment delivery from the Scottelva catchment, with contribution of material from erosion of the north end of the shoreline studies, caused the aggradation of coastal zone by over 60 m near its mouth.

Due to different reasons a significant modal shift from railway to road transport took place over last decades. The basic reasons are pointed in the paper introduction together with contradicting transport policy taking into account environmental and economical challenges. Political vision to stimulate modal shift from road and air to railway cannot become true without achieving railway technical and operational interoperability. Paper describes wide range of technical barriers between individual intraoperable railway systems in civil engineering structures, traction power supply, control command and signalling and the ways, which are being applied to ensure stepwise converging of the technical solutions taking into account safety and technical compatibility, as well as other essential requirements, namely: reliability, accessibility, health and environment.

The paper refers to planning deliveries of food products (especially those available in certain seasons) to the recipients: supermarket networks. The paper presents two approaches to solving problems of simultaneous selection of suppliers and transportation modes and construction of product flow schedules with these transportation modes. Linear mathematical models have been built for the presented solution approaches. The cost criterion has been taken into consideration in them. The following costs have been taken into account: purchase of products by individual recipients, transport services, storing of products supplied before the planned deadlines and penalties for delays in supply of products. Two solution approaches (used for transportation planning and selection of suppliers and selection of transportation modes) have been compared. The monolithic approach calls for simultaneous solutions for the problems of supplier selection and selection of transportation modes. In the alternative (hierarchical) solution approach, suppliers are selected first, and then transportation companies and their relevant transportation modes are selected. The results of computational experiments are used for comparison of the hierarchical and monolithic solution approaches.

The influence and the potential risk due to hidden faults of a relay protection system on power supply in distribution systems are paid more and more attention to. A probability analysis method is used to analyse fault characteristics and action mechanism of dominant faults, hidden misoperation and non-operation of the relay protection systems, and failure probability model of relay protection system is constructed and simplified. The effects of dominant faults, hidden misoperation and non-operation of the relay protection systems on the reduced power supply load power are analysed, and a probabilistic model for reduced power supply load power is constructed by three parts corresponding to dominant faults, hidden misoperation and non-operation. A probability calculation method of power supply risk occurrence due to hidden faults of relay protecttion system is proposed considering the fault probability of the relay protection systems, the frequency of the hidden faults occurring in operation period, the reduced power supply load power or load power outage, and the connection mode of the in-lines, out-lines and transformers in a substation. The feasibility and applicability of the proposed method for estimation of risk value probability of the relay protection systems is verified by two studied examples.

The text comprises the evaluation of relationship between the qualitative planning tools and the Irish housing policy in the pre-crisis period, during the crisis (2009-2013) and the recovery. The tools that affect housing are understood as spatial planning, including governmental regulations on densification of the development and the housing quality as well as the special tools such as the urban design. Those regulatory tools were deployed with aims to safeguard the sustainable and socially viable housing structures. The Irish case illustrates the considerable innovation in introducing new housing standards and challenges with their efficiency. This can be attributed to the lack of integration with other elements that shaped the market – financing and actions of the private market, low efficiency of planning or the lack of the scale effect for the model developments. Despite their drawbacks these tools are continuously being used, as their foundational principles are still valid.

In this paper, selected aspects of the national technical level of electric energy supply security is shown. An analysis and assessment of the electric power infrastructure in area of generation, transmission and distribution in aspects of electric energy security is conducted. The profile of the generation sector and grid infrastructure in the area of transmission and distribution is shown. The present and future situation in a range of operation of electric power infrastructure in the area of generation, transmission and distribution in the frames of the National Electric Power System in the electric energy supply security context is determined. The level of national electric energy supply security in area of generation and grid infrastructure is assessed. Threats of electric energy supply security are described and the catalogue of essential actions for the assurance of electric energy supply security are proposed. In the area of electricity generation, at present there is no danger to the electricity supply security in normal load conditions, but there is a high probability that it will occur in the future (after 2025) when the forecasted increase in electricity demand takes place and the new stringent environment protection requirements (Directive IED, BAT conclusions, Winter Package) enter into force. The network infrastructure in area of transmission and distribution is admittedly adapted for presently occurred typical conditions of electric energy demand and the realization of internal tasks in normal conditions, but can create a potential threat for electric energy supply security. In the context of the forecasted increase of electric energy demand, inadequate power generation sources in the National Electric Power System and available through intersystem connections, their uneven location on the territory of Poland in the shortage of proper network transmission capacities, the necessity of improvement of the quality and electric energy supply reliability to final consumers and the intensive development of renewable energy sources, the present network infrastructure in area of transmission and distribution will be insufficient.

The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.

Supply Chain Management (SCM) is a very important part of the industrial world, especially in the manufacturing sector. The development of the business world affects the complexity of the supply chain due to the lack of logistics infrastructure, quality of materials and components, and much more. Supply chain disruption risk mapping needs to be done due to high uncertainty, which is overcome by implementing a decision support system. Based on the background of the problem, supply chain disruption mapping uses the help of the Six Sigma method, which consists of 5 stages: Define, Measure, Analyze, Improve, and Control (DMAIC). The measurement of disturbance also uses the Failure Mode and Effect Analysis (FMEA) approach to prioritize risk. Risks that have a high assessment and cause failure need to be prioritized for improvement. This study aims to map supply chain disruptions in the current manufacturing industry based on the barriers, resistances, and causes detected for making a decision support system prototype. By implementing a decision support system in the supply chain process, it is

The purpose of this study is to solve the efficiency and reliability problems of upstream water intake structures for energy and irrigation systems in the region of the Republic of Azerbaijan. Among the methods used in the study, experimental, analytical, and modelling methods should be distinguished. During the study, analyses and field investigations of main structures, and energy and irrigation systems in the foothills were conducted to identify the reasons for the low efficiency and reliability of existing old water intake structures and reduce their negative impact on the environment. The results of the study showed that many water intake structures built on small rivers are not only in poor working condition but also do not meet modern environmental requirements. Many of these structures were built more than thirty years ago and have not been modernized or reconstructed in accordance with new technologies and requirements. As a result of the study, recommendations were prepared for the design of new water intake structures that meet all modern environmental requirements and guarantee the more efficient use of water resources. These new facilities will also help to reduce water losses during the overflow process, which will make the use of water more cost-effective. Additionally, one of the main outcomes is the developed useful model, which pertains to the field of hydroengineering construction for water intake from mountain and foothill rivers, serving as an additional barrier to reduce the influx of large sediment into the reservoir.

Recently, the expand of industrial market has led to have long supply chain network. During the long shipment, the probability of having damaged products is likely to occur. The probability of having damaged products is different between stages and that could lead to higher percentage of damaged products when arrived at retailers. Many companies have rejected the entire shipment because the damaged product percentage was higher than that agreed on. Decision-makers have tried to reduce the percentage of damaged products that happened because the transit, loading unloading the shipment, and natural disasters. Companies started to implement recovery centers in the supply chain network in order to return their system steady statues. Recovery models have been developed in this paper to reduce the damaged percentage at minimum costs to do so. Results show that the possibility of implementing an inspection unit and a recovery centers in the system before sending the entire shipment to the retailer based on examining a sample size that has been selected randomly from the shipment and the minimum cost of committing type I and type II errors. Designing a methodology to minimize the total cost associated with the supply chain system when there is a possibility of damage occurring during shipping is the objective of this research.

The paper looks at the issues of operation safety of the national power grid and the characteristics

of the national power grid in the areas of transmission and distribution. The issues of

operation safety of the national transmission and distribution grid were discussed as well as threats

to operation safety and security of the electricity supply related to these grids. Failures in the

transmission and distribution grid in 2017, caused by extreme weather conditions such as: a violent

storm at the night of 11/12.08.2017, hurricane Ksawery on 5–8.10.2017, and hurricane Grzegorz on

29–30.10.2017, the effects of which affected tens of thousands of electricity consumers and led to

significant interruptions in the supply of electricity were presented. At present, the national power

(transmission and distribution) grid does not pose a threat to the operation safety and security of

the electricity supply, and is adapted to the current typical conditions of electricity demand and the

performance of tasks during a normal state of affairs, but locally may pose threats, especially in

extreme weather conditions. A potentially high threat to the operation safety of the national power

grid is closely linked to: age, technical condition and the degree of depletion of the transmission and

distribution grids, and their high failure rate due to weather anomalies. Therefore, it is necessary

to develop and modernize the 400 and 220 kV transmission grids, cross-border interconnections,

and the 110 kV distribution grid (especially in the area of large urban agglomerations), and the MV

distribution grid (especially in rural areas). The challenges faced by the transmission and distribution

grid operators within the scope of investment and operating activities, with a view to avoiding

or at least reducing the scale of grid failures in the case of future sudden high-intensity atmospheric

phenomena, are presented.

The aim of the paper is to compare nitrate concentrations in samples of supply water as well as

water from deep and dug wells located in the eastern region of Poland. Additionally, samples of bottled water

(spring and natural mineral), certifi ed by the Institute of Mother and Child and the Children’s Memorial Health

Institute, were subjected to analyses. On the basis of the obtained results, health risks related to the occurrence

of methemoglobinemia in neonates and infants were evaluated. The risk analysis was performed according to

the procedure recommended by the United States Environmental Protection Agency. Nitrate concentrations in

the examined samples ranged from: 0.153–161.1 mg/l. The lowest concentration of nitrates was determined in

the samples of bottled water, the highest being detected in the water from dug wells. It was found that nitrate

concentration in samples of bottled and supply water did not pose any risk to the health of neonates and infants.

The highest health risk related to methemoglobinemia occurs for neonates consuming water originating from

dug wells. The risk decreases along with the age of an infant.

Along with the increase in the use of nonlinear electronic devices, e.g. personal computers, power tools and other electrical appliances, the requirements for uninterruptible power supplies are constantly growing. This paper proposes a method and deep analysis of results viable for checking how single-phase uninterruptible power supplies (UPSs) cope with nonlinear circuits under varying power loads in terms of electric energy quality.Various classes of single-phase UPS systems with different topologies were tested, for instance line-interactive and double conversion (online) single-phase UPS devices. Furthermore, measurements were carried out in view of a power source – loads were supplied both from a power grid and UPS built-in battery. Juxtaposition of the obtained results such as a THDU, THDI (Total Harmonic Distortion) percentage ratio of input/output voltage and current, a power factor and crest factor volume etc. of the tested UPS systems indicated major differences in their performance during laboratory tests.

This original paper deals with a new approach for the study of behavior in nonlinear regime of a new three-phase high voltage power supply for magnetrons, used for the microwave generators in industrial applications. The design of this system is composed of a new three-phase leakage flux transformer supplying by phase a cell, composed of a capacitor and a diode, which multiplies the voltage and stabilizes the current. Each cell. in turn, supplies a single magnetron. An equivalent model of this transformer is developed taking into account the saturation phenomenon and the stabilization process of each magnetron. Each inductance of the model is characterized by a non linear relation between flux and current. This model was tested by EMTP software near the nominal state. The theoretical results were compared to experimental measurements with a good agreement. Relative to the current device, the new systemprovides gains of size, volume, cost of implementation and maintenance which make it more economical.

As experience shows the practical, reliable assessment and optimisation of total costs of logistical processes implemented in supply chains

of foundry plants is a quite complex and complicated process, because it requires to enclose all, without exception, performed actions,

including them in various reference cross-sections, systematic activities and finally transforming them in a totally homogenous collection.

Only solid analysis and assessment of assortment management in logistical supply systems in foundry plants of particular assortment

groups allows to lower the supply costs significantly. In the article the analysis and assessment of the newest implemented optimising

algorithms are presented in the process stock management of selected material groups used in a production process of a chosen foundry

plant. A practical solution to solve a problem of rotary stock cost minimisation is given as well as of costs while creating a stock with the

usage of economical volume and value of order.

The proper description of circuits supplied from an asymmetrical and sinusoidal voltage source, in which line parameters are included, requires an adequate mathematical concept or theory. The authors of the publication present the mathematical concept of the currents’ asymmetrical components for three-phase four-wire systems, taking into account the impedance of the neutral conductor and the impedance of power transmission lines. In the new approach, four orthogonal current components were proposed in charge of its flow between the source and the load. The introduced distribution shows, regardless of the type of the voltage asymmetry (amplitude or phase), it is possible to set down the symmetrical active current and other components, i.e. reactive current, negative current and zero current, which will allow determining the reference current of the active filter.

The objectives of this research are to study the direct influence on the competitive advantage

and pattern development of variables affecting the competitive advantage of the Thai oil

palm industry. This research employs a quantitative research method. The population for

the study consists of 150 oil palm industrial operators in Thailand. Questionnaires are used

in the data collection and the data are analyzed by using SEM. The research results reveal

that the Knowledge Management Process and Supply Chain Integration positively influence

the competitive advantage in the quality, delivery, and cost. The competitive advantage

receives a positive direct impact from the Knowledge Management Process and Supply

Chain Integration. The variation of competitive advantage can be explained as 84%. The

obtained results can be used for developing the industry to create economic growth and

sustainable competitive advantage.

This paper addresses supply chain transparency improvement in a triadic manufacturersupplier-

supplier relationship. It investigates the problem of improving transparency using

a set of interviews; then, a detailed problematization and a simulation model is formulated

based on the results. The interview results show that there are two key issues to be considered:

information systems issues related directly to transparency and capability issues related

to utilizing transparency. The simulation results support developing capabilities by illustrating

the effects of different options for coordinating material flow. The results of the study

also indicate that while solutions to improve transparency can be relatively straightforward

to implement, developing the capability to benefit from it can be more challenging, even in

a well-established close partnership. In addition, suppliers may be hesitant to collaborate

without active manufacturer involvement.