During implementation of construction projects, durations of activities are affected by various factors. Because of this, both during the planning phase of the project as well as the construction phase, managers try to estimate, or predict, the length of any delays that may occur. Such estimates allow for the ability to take appropriate action in terms of planning and management during the execution of construction works. This paper presents the use of the non-deterministic concept for describing the uncertainty of estimating works duration. The concept uses the theory of fuzzy sets. The author describes a method for fuzzy estimations of construction works duration based on the fact that uncertain data is an inherent factor in the conditions of construction projects. An example application of the method is presented. The author shows a fuzzy estimation for the duration of an activity, taking into consideration the distorting influence caused by malfunctioning construction equipment and delivery delays of construction materials.

For the construction company, tendering is the most popular way of acquiring contracts. The decision to participate in the tender needs to be made carefully, as it affects the condition of the company and is an important aspect in its quest for success. The bid/no bid decision making is a complex process involving a number of factors. The research carried out so far has mainly concerned the identification of the various kinds of influences on contractors’ bidding decisions. The researchers, on the basis of contractors’ opinions, created rank lists in an attempt to categorize the factors. In this paper the author employs factor analysis which belongs to basic methods of multi-dimensional data analysis. The paper’s aim is first to depict an output set of observed variables, that is bid/no bid factors, in terms of a smaller set of latent variables which cannot be directly observed and then to interpret the dependencies between them.

Author’s aim is to highlight problems related to the course of regulatory processes in the structures of the living organism. In this research area the question arises what is the task of causal factors and mechanisms governing regeneration processes, including building new parts of the body. Despite the vast knowledge already gained in this field, the way to restore the functional regeneration of some structures of the organism is still to be discovered.

In order to prepare a coal company for the development of future events, it is important to predict how can evolve the key environmental factors. This article presents the most important factors influencing the hard coal demand in Poland. They have been used as explanatory variables during the creation of a mathematical model of coal sales. In order to build the coal sales forecast, the authors used the ARMAX model. Its validation was performed based on such accuracy measures as: RMSE, MAPE and Theil’s index. The conducted studies have allowed the statistically significant factors out of all factors taken into account to be identified. They also enabled the creation of the forecast of coal sales volume in Poland in the coming years. To maintain the predictability of the forecast, the mining company should continually control the macro environment. The proper demand forecast allows for the flexible and dynamic adjustment of production or stock levels to market changes. It also makes it possible to adapt the product range to the customer’s requirements and expectations, which, in turn, translates into increased sales, the release of funds, reduced operating costs and increased financial liquidity of the coal company. Creating a forecast is the first step in planning a hard coal mining strategy. Knowing the future needs, we are able to plan the necessary level of production factors in advance. The right strategy, tailored to the environment, will allow the company to eliminate unnecessary costs and to optimize employment. It will also help the company to fully use machines and equipment and production capacity. Thanks to these efforts, the company will be able to reduce production costs and increase operating profit, thus survive in a turbulent environment.

The aim of the study was to evaluate the combined effect of noise exposure and additional risk factors on permanent hearing threshold shift. Three additional risk factors were: exposure to organic solvents, smoking and elevated blood pressure.

The data on exposure and health status of employees were collected in 24 factories. The study group comprised of 3741 noise male exposed workers of: mean age 39±8 years, mean tenure 16±7 years and LEX,8h = 86 ± 5 dB. For each subject, hearing level was measured with pure tone audiometry, blood pressure and noise exposure were assessed from the records of local occupational health care and obligatory noise measurements performed by employers. Smoking and solvent exposure were assessed with questionnaire. The study group was divided into subgroups with respect to the considered risk factors. In the analysis, the distribution of hearing level of each subgroup was compared to the predicted one which the standard calculation method described in ISO 1999:1990. For each of the considered risk factors, the difference between measured and calculated hearing level distribution was used to establish, by the least square method, a noise dose related correction square function for the standard method. The considered risk factors: solvent exposure, smoking and elevated blood pressure combined with noise exposure, may increase degree of hearing loss.

Management and Production Engineering Review (MPER) is a peer-refereed, international, multidisciplinary journal covering a broad spectrum of topics in production engineering and management. Production engineering is a currently developing stream of science encompassing planning, design, implementation and management of production and logistic systems. Orientation towards human resources factor differentiates production engineering from other technical disciplines. The journal aims to advance the theoretical and applied knowledge of this rapidly evolving field, with a special focus on production management, organisation of production processes, management of production knowledge, computer integrated management of production flow, enterprise effectiveness, maintainability and sustainable manufacturing, productivity and organisation, forecasting, modelling and simulation, decision making systems, project management, innovation management and technology transfer, quality engineering and safety at work, supply chain optimization and logistics. Management and Production Engineering Review is published under the auspices of the Polish Academy of Sciences Committee on Production Engineering and Polish Association for Production Management. The main purpose of Management and Production Engineering Review is to publish the results of cutting-edge research advancing the concepts, theories and implementation of novel solutions in modern manufacturing. Papers presenting original research results related to production engineering and management education are also welcomed. We welcome original papers written in English. The Journal also publishes technical briefs, discussions of previously published papers, book reviews, and editorials. Letters to the Editor-in-Chief are highly encouraged.

Fatigue cracks in machine components are subjected to stress fields induced by the external load and residual stresses resulting from the surface treatment. Stress fields in such cases are characterized by non-uniform distributions and handbook stress intensity factor solutions for such configurations are not available. The method presented below is based on the generalized weight function technique enabling the stress intensity factors to be calculated for any Mode I loading applied to arbitrary planar convex crack. The method is particularly suitable for modeling fatigue crack growth in presence of complex stress fields.

This chapter provides a quantitative analysis to identify weak regions that have changed the innovation model. The analysis was carried out at the beginning of the project, in 2015, when only data on GDP per capita for the EU regions was available until 2011. It was designed to identify regions that have changed the innovation model for their in-depth qualitative research, that is to prepare case studies. To indicate the development paths of European regions, a comparative analysis of means was prepared. Innovation models and their change were indicated by clusters analysis. In addition, an econometric analysis of growth factors in the EU regions covering data on GDP per capita in the EU regions in 2014 was carried out in 2017.

The aim of this research was to assess the content and composition of the pollutants emitted by domestic central heating boilers equipped with an automatic underfeed fuel delivery system for the combustion chamber. The comparative research was conducted. It concerned fuel properties, flue gas parameters, contents of dust (fl y ash) and gaseous substances polluting the air in the flue gases emitted from a domestic CH boiler burning bituminous coal, pellets from coniferous wood, cereal straw, miscanthus, and sunflower husks, coniferous tree bark, and oats and barley grain. The emission factors for dust and gaseous air pollutants were established as they are helpful to assess the contribution of such boilers in the atmospheric air pollution. When assessing the researched boiler, it was found out that despite the development in design and construction, flue gases contained fly ash with a significant EC content, which affected the air quality.

The accumulation and translocation of trace metals in soil and in sugarcane crop irrigated with treated effluents from sugar industry compared to soil and sugarcane crop irrigated with bore-well water were determined. In the present study the impact of irrigation with treated effluent from the sugar industry on the trace metal contamination of sugarcane juice was assessed. It revealed that the mean concentrations of Cd, Pb, Cu, Mn and Zn in the soil of fields irrigated with effluent and in juice from sugarcane grown on such fields were higher than those from bore-well water irrigated fields. The concentrations of trace metals in treated effluent exceeded the permissible limits of the Indian standards (Central Pollution Control Board-2000). The concentrations of Cd, Pb, Cu and Zn in juice of sugarcane grown on fields irrigated with effluent also exceeded the permissible limits of Indian standards and WHO/FAO expert committee recommendations. Their concentrations in juice of sugarcane grown in fields irrigated with bore-well water were within the limits of safety, except for Cd. The transfer factor for Zn was considerably higher than those of the other trace metals. The metal concentrations of sugarcane juice showed significant correlations with those of soil, which was not the case when bore well water was used for irrigation.

W publikacji tej opisano właściwości fizykochemiczne szlamów arsenowych pozostałych po flotacji rud arsenowych i porastające je rośliny. Miejscem badań jest Złoty Stok - kolebka światowej metalurgii arsenu (1709-1961). Stwierdzono, że w warstwie ryzosfery (O- 25 cm) jest bardzo mało N, Na, Fe i próchnicy, mało P, średnia zawartość Ca i K oraz bardzo dużo Mg. Ich odczyn jest zasadowy. Analiza roślinności wykazała, że przez ok. 40 lat na szlamach pojawiło się 67 gatunków roślin naczyniowych. Są to wyłącznie apofity, wśród których dominują hemikryptofity, rośliny światłolubne i neutralne w stosunku do kontynentalizmu klimatu oraz mezofity i higrofity, mezo- i eutrofy oraz acidofilne do bazyfilnych. Gatunkiem dominującym jest Calamagrostis epigejos (L.), rzadziej występuje Carlina vulgaris L., Centaurea phrygia L., C. scabiosa L., Daucus carota L. i Festuca rubra L.

Some aspects of the epidemiology of Maize streak virus (MSV) genus Mastrevirus concerning virus incidence, vector populations and some environmental factors were investigated in field experiments conducted over a three year period (2000–2002) at Samaru, northern Nigeria. Significant positive correlations were obtained between number of leafhoppers caught and MSV incidence and age of plant at infection and also with temperature. Also significant negative correlations were obtained between MSV incidence and mean relative humidity; between number of leafhoppers and age of plants and with mean rainfall. Leafhopper vectors caught included Cicadulina arachidis China, C. mbila Naude, C. triangula Ruppel and C. similis China, in order of abundance. Leafhopper incidence was highest in the months of September and October.

In the article problems related to human labor and factors affecting the increasing use of

industrial robots are discussed. Since human factors affect the production processes stability,

robots are preferred to apply. The application of robots is characterized by higher performance

and reliability comparing to human labor. The problem is how to determine the real

difference in work efficiency between human operator and robot. The aim of the study is to

develop a method that allows clearly definition of productivity growth associated with the

replacement of human labor by industrial robots. Another aim of the paper is how to model

robotized and manual operated workstation in a computer simulation software. Analysis of

the productivity and reliability of the hydraulic press workstation operated by the human

operator or an industrial robot, are presented. Simulation models have been developed taking

into account the availability and reliability of the machine, operator and robot. We apply

OEE (Overall Equipment Effectiveness) indicator to present how availability and reliability

parameters influence over performance of the workstation, in the longer time. Simplified

financial analysis is presented considering different labor costs in EU countries.

Introduction: Clostridium difficile (C. difficile) is a Gram-positive, anaerobic rod-shaped bacteria, widely spread in the human environment. In the last decade, the frequency and severity of Clostridium difficile infection (CDI) have been increasing, making this particular disease one of the most significant nosocomial infections. The aim of our study was an analysis of CDI risk factors, its course and consequences.

Materials and Methods: Medical documentation of the patients treated for CDI in the University Hospital in Cracow and St Anne’s Hospital in Miechów has been analysed. The analysis focused on epidemiological data, blood parameters, comorbidities, recurrence rate, and complication rate (deaths included). As part of risk factors analysis, antibiotic use or hospitalisation in a period of 3 months before the episode of infection was considered relevant. Blood tests have been performed using routinely employed, standard methods.

Results: We evaluated data of 168 people infected with C. difficile, out of which there were 102 women (61%) and 66 men (39%). Th e median age of the patients was 74 years for the entire population with 76 years for women and 71 years for male patients. One hundred thirteen people (67%) had been previously hospitalised, and 5 person was a pensioner of a nursing home. 99 people (59%) were treated with antibiotics within 3 months before the first episode of infection. An average length of the hospital stay because of CDI was 11 days. One hundred thirty persons (77%) experienced only 1 episode whereas 38 people (23%) had more than 1 episode of infection. The person with the largest number of recurrences had 9 of them.

Conclusions: The development of CDI is an increasing problem in a group of hospitalised persons, particularly of an old age. The general use of beta-lactam antibiotics is the cause of a larger number of infections with C. diffi cile. Vast majority of patients have had at least one typical risk factor of CDI development.

The aim of the article is to present international economic integration as one of the mega trends that infl uence on the redefi nition of the factors of socio-economic development. The research procedure includes three stages. In the fi rst stage, the most important modern mega trends of socio-economic changes are organized in a synthetic way. In the second step, the genesis and changes of the process of international economic integration are elaborated. In the third stage, the infl uence of international economic integration on the changes of factors of socio-economic development is systematized. This study is being carried out as part of the FORSED research project (http://www.forsed.amu.edu.pl) fi nanced by the National Science Center as part of OPUS competition 10 – 2015/19/B/HS5/00012: New challenges of regional policy in shaping the socio-economic development factors of less developed regions.

The relevance of this study is due to the fact that the presented object of scientific work, namely 6–10 kV overhead lines, plays an important role in the process of providing electrical energy to consumers of the oil industry. The aim of the work is a detailed analysis of the reliability of overhead lines which are exploited in the difficult natural and climatic conditions of the Caspian region and Mangyshlak and the introduction of effective modeling tools for overhead lines. The methods used include the analytical method, theoretical method, logical analysis method, functional method, statistical method, synthesis method and others. In the course of the study, the natural and climatic conditions of the Atyrau region and their differences were noted and the reliability of the power supply systems was also analyzed. The most damaged elements of industrial power supply systems and their part of failures were identified in comparison with other elements of the power supply system. It was determined that the electrical power sector plays a crucial role in the oil and gas sector by determining the solution of the production tasks of all departments which have a significant impact on the formation of economic indicators. The practical value of the revealed results is that they will help to highlight the problems of operational reliability of the 6–10 kV overhead lines, considering the various natural and climatic factors, which in turn will help to change the power supply scheme and increase the resistance to external influences.

Livestock production is the basis of global food production and it is a serious threat to the environment. Significant environmental pollutants are odors and ammonia (NH3) emitted from livestock buildings. The aim of the study was to determine the concentration and emission factors of ammonia and odors, in the summer season, from a deep-litter fattening house. The research was carried out during summer in a mechanically ventilated fattening piggery located in the Greater Poland Voivodeship. Ammonia concentrations were measured using photoacoustic spectrometer Multi Gas Monitor Innova 1312, and odor concentrations were determined by dynamic olfactometry according to EN 13725:2003 using a TO 8 olfactometer. The NH3 emission factors from the studied piggery, in summer, ranged from 8.53 to 21.71 g·day-1·pig-1, (mean value 12.54±4.89 g·day-1·pig-1). Factors related to kg of body mass were from 0.11 to 0.23 g·day-1·kg b.m.-1 (mean value 0.17±0.06 g·day-1·kg b.m.-1). Odor concentrations in the studied piggery were from 755 to 11775 ouE·m-3 and they were diversified (coefficient of variation 43.8%). The mean value of the momentary odor emission factors was 179.5±78.7 ouE·s-1·pig-1. Factor related to kg of body mass was 2.27±1.71 ouE·s-1·kg b.m.-1. In Poland and many other countries, the litter systems of pigs housing are still very popular. Therefore, there is a need to monitor the pollutant emissions from such buildings to identify the factors influencing the amount of this emission. Another important issue is to verify whether the reduction techniques, giving a measurable effect in laboratory research, bring the same reduction effect in production

The emission rate of fibers released lrorn the new/fresh and used/worn ceramic fiber material. glass wool and man-made mineral fiber material due lo mechanical impact was determined experimentally. The emission rate has been defined as a number or fibers emitted per unit mass and unit impaction energy. The averaged emission rate of short fibers (LS 5 run) for all studied fresh non-asbestos fiber materials ranged lrom 2.2 to 20 fibers/(g·.l), while the emission or long fibers (I,> 5 urn) was between 2.2 and I 00 fibers/(g·J). The susceptibility or worn fiber-containing materials 10 emitting fibrous particles due 10 mechanical impaction was significantly diverse. Emission from glass wool unchanged with the exploitation, while the emission rate of the mineral fiber material increased by a factor of I O·' compared 10 new material. The dominating population or emitted fibers from studied materials ranged trorn 2 10 around 8 pm in length.

The relative relationships “yield – evapotranspiration” were used long time ago. The well known linear relationship yi = 1 – ky (1 – ei), where yi is relative yield, ky – yield response factor and ei – relative evapotranspiration was proposed. It’s usually assumed that ky is constant for a given crop and climatic conditions. It was found, however, that ky for late variety of maize H 708 varied through the study years (1984–1990) in the Plovdiv region (South Bulgaria, altitude 150 m). During the dry years it was significantly higher than in the medium and humid years. The range of ky for maize in this location was 1.12–1.90, the average value being 1.50. The climate in the Sofia region (the ex-perimental field of Chelopechene, altitude 550 m) is comparatively more humid. The two regions approximately outlined the boundaries of the appropriate economical conditions for grain maize pro-duction. The experiments in the Sofia region were carried out in the years 1994–2000. The seven years results for mean variety maize showed that the relationships “yield – evapotranspiration” and, respectively, ky varied at these climatic conditions too. The highest ky value was 1.41 for the driest year (2000) and the lowest value – 1.05 for the most wet years (1995, 1999). The value of ky for av-erage years was 1.21. The yield response factor ky is of more significance when the relative evapotranspiration is less than 0.7–0.8. Thus, the extreme or the average values of ky could be used for the corresponding climatic regions. The relationships between ky and relative yield were estab-lished without considering irrigation.