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Number of results: 18
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Abstract

The presence of the spare parts stock is a necessity to ensure the continuity of services. The supply of spare parts is a special case of the global supply chain. The main objective of our research is to propose a global spare parts management approach which allows decision makers to determine the essential points in stock management. Thus, it is important for the stock manager to evaluate the system considered from time to time based on performance indicators. Some of these indicators are presented in the form of a dashboard. The presentation of this chapter chronologically traces the progress of our research work. In the first part, we present the work related to the forecast of spare parts needs through parametric and statistical methods as well as a Bayesian modelling of demand forecasting. To measure the appreciation of the supply of spare parts inventory, the second part focuses on work related to the evaluation of the performance of the spare parts system. Thus, we concretize the link between the management of spare parts and maintenance in the third part, more precisely, in the performance evaluation of the joint -management of spare parts and maintenance, in order to visualize the influence of parameters on the system. In the last section of this chapter, we will present the metaheuristic methods and their use in the management of spare parts and maintenance and make an analysis on work done in the literature.
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Authors and Affiliations

Oumaima Bounou
1
Abdellah El Barkany
1
Ahmed El Biyaali
1

  1. Mechanical Engineering Laboratory, Faculty of Science and Techniques, Morocco
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Abstract

This research addresses an inventory classification problem in a company that manufactures plastic pallets. Classification of the inventory is difficult because it is subject to two restrictions: the number of changeovers and the size of inventory storage. A mathematical model is first proposed to maximize the fill rate by classifying all product items into four groups. Due to all items can be classified based on the monthly demand, in descending order. The present study then proposed a procedure to find the classification that is most efficient. According to the experimental results, the maximum fill rate in the current situation is 89.85%. The proposed methodology also tested different production batches and levels of demand. The proposed methodology was found to be appropriate for practical application.
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Authors and Affiliations

Yiyo KUO
Hao-Chen JIANG
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Abstract

This paper explores the psychometric properties of the Polish adaptation of the MBI-SS questionnaire, which measures academic burnout in students. The factorial structure of the tool was examined, and its validity was evaluated using a sample from Polish state universities (N=935).
Findings suggest that the MBI-SS possesses strong psychometric parameters. Data supports the tool's 3-factor structure and internal consistency. However, there are reservations regarding one item (MBI_6). Consequently, the 15- item version of the MBI-SS is recommended as a suitable tool for assessing burnout in Polish students.
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Authors and Affiliations

Teresa Chirkowska-Smolak
1
ORCID: ORCID
Tomasz Górecki
1
Mateusz Klakus
1
ORCID: ORCID
Weronika Metzger
1
Martyna Szargan
1

  1. Adama Mickiewicza University, Poznań, Poland
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Abstract

The inventory systems are highly variable and uncertain due to market demand instability, increased environmental impact, and perishability processes. The reduction of waste and minimization of holding and shortage costs are the main topics studied within the inventory management area. The main difficulty is the variability of perishability and other processes that occurred in inventory systems and the solution for a trade-off between sufficient inventory level and waste of products. In this paper, the approach for resolving this trade-off is proposed. The presented approach assumes the application of a state-feedback neural network controller to generate the optimal quantity of orders considering an uncertain deterioration process and the FIFO issuing policy. The development of the control system is based on state-space close loop control along with neural networks. For modelling the perishability process Weibull distribution and FIFO policy are applied. For the optimization of the designed control system, the evolutionary NSGA-II algorithm is used. The robustness of the proposed approach is provided using the minimax decision rule. The worst-case scenario of an uncertain perishability process is considered. For assessing the proposed approach, simulation research is conducted for different variants of controller structure and model parameters. We perform extensive numerical simulations in which the assessment process of obtained solutions is conducted using hypervolume indicator and average absolute deviation between results obtained for the learning and testing set. The results indicate that the proposed approach can significantly improve the performance of the perishable inventory system and provides robustness for the uncertain changes in the perishability process.
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Authors and Affiliations

Ewelina Chołodowicz
1
ORCID: ORCID
Przemysław Orłowski
1
ORCID: ORCID

  1. Faculty of Electrical Engineering, Department of Automation and Robotics, West Pomeranian University of Technology in Szczecin,al. Piastów 17, 70-310 Szczecin, Poland
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Abstract

This study investigates cadmium (Cd) accumulation in the plant leaves of juglans regia (walnut) and cydonia oblanga (quince) trees related to traffic emissions on the highway roadside. The plant leaf samples were collected from 20 sites on the D-100 Highway roadside and washed with deionized water before analyzed. Determination of Cd was carried out using an inductively-coupled plasma-mass spectrometer after microwave digestion of the samples. Cd concentration on the plant leaves was found to be between 0.04–0.11 mg/kg. In order to determine the traffic-based emissions, vehicles were counted and an emission inventory was prepared. 0.18 tons of Cd was found to be delivered into the atmosphere every day. Cd accumulation depends on traffic density because there were no residential area and industrial plants. The distribution of Cd accumulation caused by traffic emissions was mapped by using a geographic information system (GIS). The maps showed that the Cd accumulation was high in the areas near the highway and then gradually decreased by moving away from the highway.

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Authors and Affiliations

Merve Çolak
Mahnaz Gümrükçüoğlu
Füsun Boysan
Erkan Baysal
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Abstract

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

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Authors and Affiliations

Miriam Pekarcıkova
Peter Trebuna
Marek Kliment
Jozef Trojan
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Abstract

Hornsund, an Arctic fjord in the west coast of Spitsbergen (Svalbard), was selected as All Taxa Biodiversity Inventory (ATBI) site under EU 5th Framework Concerted Action BIOMARE (2000–2002), especially due to its pristine, undisturbed natural character. On the base of large material (89 stations located throughout the fjord and 129 Van Veen grab samples) collected during cruises of RV Oceania in July in 2002, 2003, 2005 and 2007 and literature search a comprehensive list of species recorded within Hornsund area, on the soft bottom with depth range of 30–250 m is provided. Over 220 species were identified including 93 species of Polychaeta, 62 species of Mollusca and 58 species of Crustacea. Species list is supported by information on the zoogeographical status, body length and biological traits of dominant species. Need for further research on Hornsund soft bottom fauna with more sampling effort is highlighted.
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Authors and Affiliations

Monika Kędra
Sławomira Gromisz
Radomir Jaskuła
Joanna Legeżyńska
Barbara Maciejewska
Edyta Malec
Artur Opanowski
Karolina Ostrowska
Maria Włodarska-Kowalczuk
Jan Marcin Węsławski
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Abstract

The paper considers the negative pandemic-type demand shocks in the mean-variance newsvendor problem. It extends the previous results to investigate the case when the actual additive demand may attain negative values due to high prices or considerable, negative demand shocks. The results indicate that the general optimal solution may differ to the solution corresponding exclusively to the non-negative realizations of demand.
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Authors and Affiliations

Milena Bieniek
1

  1. Maria Curie-Sklodowska University, Lublin, Poland
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Abstract

Scheuchzeria palustris is a species regarded as an arctic-boreal relic and critically en-dangered. The study was conducted on one of the recent stands in the Łódź region, in the Czarny Ług Reserve, located near Wolbórz. The primary aim of the study was to know the amount of this species and the associated species. Quantitative, morphological and floristic features were ana-lysed. In the study area occurred about 150 specimens per 1 m2. Among the associated species were found species representing classes: Scheuchzerio-Caricetea Nigrae and Oxycocco-Sphagnetea. Eriopho-prum angustifolium was dominant among the first class species (60% coverage), while Andromeda polifolia and Oxycoccus palustris from the second class. From here it can be assumed that the succession will be in the direction of Scheuchzerio-Caricetea Nigrae. However, high water levels may inhibit this process. Specific biotic and abiotic conditions allow for the survival of this spe-cies. This is visible, among other things, in the mosaic structure of the studied stand.
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Authors and Affiliations

Ryszard Plackowski
Joanna Sender
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Abstract

The paper investigates the air quality in the urban area of Warsaw, Poland. Calculations are carried out using the emissions and meteorological data from the year 2012. The modeling tool is the regional CALMET/CALPUFF system, which is used to link the emission sources with the distributions of the annual mean concentrations. Several types of polluting species that characterize the urban atmospheric environment, like PM10, PM2.5, NOx, SO2, Pb, B(a)P, are included in the analysis. The goal of the analysis is to identify the most polluted districts and polluting compounds there, to check where the concentration limits of particular pollutants are exceeded. Then, emission sources (or emission categories) which are mainly responsible for violation of air quality standards and increase the adverse health effects, are identified. The modeling results show how the major emission sources – the energy sector, industry, traffic and the municipal sector – relate to the concentrations calculated in receptor points, including the contribution of the transboundary inflow. The results allow to identify districts where the concentration limits are exceeded and action plans are needed. A quantitative source apportionment shows the emission sources which are mainly responsible for the violation of air quality standards. It is shown that the road transport and the municipal sector are the emission classes which substantially affect air quality in Warsaw. Also transboundary inflow contributes highly to concentrations of some pollutants. The results presented can be of use in analyzing emission reduction policies for the city, as a part of an integrated modeling system.

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Authors and Affiliations

Piotr Holnicki
Andrzej Kałuszko
Zbigniew Nahorski
Krystyna Stankiewicz
Wojciech Trapp
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Abstract

This article presents data on the anthropogenic air emissions of selected substances (CO2, SO2, total suspended particles (TSP), dioxins

and furans (PCDD/F), Pb and Cd) subject to reporting under the Climate Convention (UNFCCC) or the Convention on Long-range

Transboundary Air Pollution (UNECE CLRTAP). It also presents the national emissions of these substances in 2014 by the major source

categories and defines the share of metal production in these emissions. Analysis is based on national emission inventory reports. Most

important source of air emission in case of CO2 and SO2 is 1.A.1 Energy industries category. TSP and PCDD/F are emitted mainly from

fuel combustion in small sources (i.a. households). Emission of heavy metals (Pb and Cd) is connected mostly with 1.A.2. Manufacturing

industries and construction category. Metallurgy is significant source of emission only for lead and cadmium from among all considered

substances. The shares of particular sectors in the national emissions of given pollutants are important, in view of the possible reduction

measures and the determination in which industries they could bring about tangible results.

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Authors and Affiliations

I. Kargulewicz
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Abstract

The performance of ten wickless heat pipes without adiabatic sections is investigated experimentally at low heat inputs 120 to 2000 W/m2 for use in solar water heaters. Three heat pipe diameter groups were tested, namely 16, 22, and 28.5 mm. Each group had evaporator lengths of 1150, 1300, and 1550 mm, respectively, with an extra evaporator length of 1800 mm added to the second group. The condenser section length of all heat pipes was 200 mm. Ethanol, methanol, and acetone were utilized as working fluids, at inventory of 25%, 50%, 70%, and 90% by evaporator volume respectively. The 22 mm diameter pipes were tested at inclination angles 30◦, 45◦, and 60◦. Other diameter groups were tested at 45◦ only. Experiments revealed increased surface temperatures and heat transfer coefficients with increased pipe diameter and evaporator length, and that increased working fluid inventory caused pronounced reduction in evaporator surface temperature accompanied by improved heat transfer coefficient to reach maximum values at 50% inventory for the selected fluids. Violent noisy shocks were observed with 70% and 90% inventories with the tested heat pipes and the selected working fluids with heat flux inputs from 320–1900 W/m2. These shocks significantly affected the heat pipes heat transfer capability and operation stability. Experiments revealed a 45◦ and 50% optimum inclination angle of fill charge ratio respectively, and that wickless heat pipes can be satisfactorily used in solar applications. The effect of evaporator length and heat pipe diameter on the performance was included in data correlations.

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Authors and Affiliations

Hassan Naji Salman Al-Joboory
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Abstract

The main objective of this study was to analyse the psychometric properties of the Polish adaptation of the Kenny Music Performance Anxiety Inventory – Revised (K -MPAI -R, Kenny, 2009) modified as the Kenny Performance Anxiety Inventory (K -PAI) for a general population of individuals with experience in public performance in fields other than music. Another aim was to test the factor structure of K -PAI on a Polish sample. We analysed the relationship between the scores on K -PAI and general anxiety, depression, attentional control, the scores on the Behavioural Inhibition Scale (BIS) and the Behavioural Activation Scale (BAS) and reward susceptibility. Participants (N = 586) completed the questionnaires in a wider online study. The scores on K -PAI revealed a moderate to strong positive association with different measures of anxiety, trait -anxiety in particular, and negative associations with attentional control and susceptibility to reward. K -PAI scores were strongly associated with depression, but displayed no relationship with the BAS or any of its sub -dimensions. These results generally replicated those obtained on the K -MPAI -R with Australian and Peruvian musicians, indicating the cross -cultural validity of the K -MPAI -R and K -PAI. It is suggested that performance anxiety develops on the basis of the biological predispositions and early negative experiences in performance contexts.
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Authors and Affiliations

Joanna Kantor-Martynuska
Dianna T. Kenny
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Abstract

Results of life cycle inventory (LCI) and life cycle assessment (LCA) for septic tanks collecting domestic sewage were presented. The study included the whole life cycle: construction, use and end-of-life stages of septic tanks. The analyses were conducted basing on actual data concerning performance of 793 septic tanks in Żory. Environmental impact assessment of the life cycle of septic tanks was conducted with TRACi and ReCiPe methods. Greenhouse gas (GHG) emission, eutrophication, fossil fuel depletion and metal depletion indicators were calculated and determinants of LCA of septic tanks were analysed. The system boundary was from cradle to grave. It was concluded that at the construction stage, GHG emission and fossil fuel depletion indicators are determined by the amount of concrete, steel, polyester resin, polyethylene, cast iron and PCV. At the use stage, GHG emission is determined by the amount and type of electricity used to treat sewage in a wastewater treatment plant (WWTP). Untreated wastewater, introduced into the environment (leaking tanks and users discharging sewage), is a determinant of infl uence on eutrophication. Life cycle inventory and environmental assessment of septic tanks with life cycle perspective are presented in the literature for the fi rst time. The results highlight the importance of including each stage in the environmental assessment of elements of the urban wastewater system.

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Authors and Affiliations

Dorota Burchart-Korol
Paweł Zawartka
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Abstract

The article presents results of an input-output data inventory and life cycle assessment (LCA) for individual wastewater treatment plants (IWWTPs), considering their whole life cycle, including the stage of construction, use and end-of-life. IWWTPs located in the area of a medium-sized town in Poland, were assessed from a systemic perspective. The research was conducted basing on actual data concerning performance of 304 individual wastewater treatment plants in Żory. Environmental assessment was conducted with ReCiPe and TRACI methods. Greenhouse gases (GHG) emission, eutrophication, fossil fuel and metal depletion were calculated. The LCA was conducted basing on ISO 14040 standard with SimaPro 8 software and Ecoinvent 3 database. The system boundary ranged from cradle to grave. It was shown that, at the construction stage, GHG emission depends on the amount of used cement, polyethylene, concrete, PVC and polypropylene. At the use stage, the GHG emission is determined by the sewage treatment technology and application of a bio-reactor in IWWTPs. At the construction stage, the fossil fuel depletion is determined by the amount of used polyethylene, PVC, cement, polypropylene and concrete; while the metal depletion is determined by the amount of used stainless steel, copper and cast iron. Data inventory and LCA of IWWTPs are presented for the first time. Conclusions of the work may support decisions taken by local governments concerning wastewater management in their area and promote and support solutions of high ecological standards.

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Authors and Affiliations

Dorota Burchart-Korol
Paweł Zawartka
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Abstract

The supply chain of spare parts is the intersection between the supply chain, the after-sales

and the maintenance services. Some authors have tried to define improvement paths in terms

of models to satisfy the performance criteria. In addition, other authors are directed towards

the integration of risk management in the demand forecasting and the stock management

(performance evaluation) through probabilistic models. Among these models, the probabilistic

graphical models are the most used, for example, Bayesian networks and petri nets.

Performance evaluation is done through performance indicators.

To measure the appreciation of the supply of the spare parts stock, this paper focuses on the

performance evaluation of the system by petri nets. This evaluation will be done through

an analytical study. The purpose of this study is to evaluate and analyze the performance of

the system by proposed indicators. First, we present a literature review on Petri nets which

is the essential tool in our modeling. Secondly, we present in the third section the analytical

study of the model based on bath deterministic and stochastic petri networks. Finally, we

present an analysis of the proposed model compared to the existing ones.

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Authors and Affiliations

Bounou Oumaima
Abdellah El Barkany
Ahmed El Biyaali
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Abstract

The Hong Kong Convention is an international attempt to regulate the scrapping of seagoing ships. It aims to ensure that ships recycled at the end of their lives do not pose unnecessary risks to health, safety and the environment. It aims to address all problems associated with ship recycling, including the fact that ships sold for scrap may contain environmentally hazardous substances such as asbestos, heavy metals, hydrocarbons, ozone-depleting substances and others. The Convention provisions also aim to improve working and environmental conditions at many ship recycling sites around the world. The second part of this article on the scrapping of seagoing ships is a translation into Polish of the English text of the Convention adopted in May 2009 by the International Conference on the Safe and Environmentally Sound Recycling of Ships.
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Bibliography

Ahmed I., Towards a Safe and Sustainable Industry of Ship Breaking: International Initiatives and South Asian Response, Journal of Maritime Law&Commerce, vol. 51, nNo. 3, July, 2020, s. 226; https://www.jmlc.org/Ahmed.pdf [dostęp 1.09.2021 r.]
Contradiction in Term: European Union must align its waste ship exports with international law and green deal, September 2020, s. 3; https://shipbreakingplatform.org/wp-content/uploads/2020/09/Report-EU-SRR-Ban-Amendment-BAN-EEB-GP--SBP.pdf [dostęp 1.09.2021 r.]
Gopal M., Beached Waste and Wasted Beaches: A Critical Analysis of the New Ship Recycling Law in India; rsrr.in/wp-content/uploads/2021/05/Meera-Gopal.pdf [do-stęp 1.09.2021 r.]
Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, 2009. https://www.basel.int/Portals/4/Basel%20Convention/docs/ships/HongKong-Convention.pdf [dostęp 1.09.2021 r.]
Mikelis N., Developments in Ship Recycling in 2019, The Maritime Executive; https://maritime-executive.com/editorials/developments-in-ship-recycling-in-2019 [dostęp 1.12.2020 r.]
Rozporządzenie Parlamentu Europejskiego i Rady (UE) nr 1257/2013 z dnia 20 listo-pada 2013 r. w sprawie recyklingu statków oraz zmieniające rozporządzenie (WE) nr 1013/2006 i dyrektywę 2009/16/WE, Dz. Urz. UE L 330 z 10.12.2013, s. 1
UNCTAD, Review of Maritime Transport 2020, s. 45; https://unctad.org/system/files/official-document/rmt2020_en.pdf [dostęp 1.09.2021 r.]
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Authors and Affiliations

Cezary Łuczywek
1
ORCID: ORCID

  1. Deputy Managing Director w przedsiębiorstwie zarządzającym statkami (ship manager) Green Management Gdynia
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Abstract

In this article, we review the research state of the bullwhip effect in supply chains with

stochastic lead times. We analyze problems arising in a supply chain when lead times are

not deterministic. Using real data from a supply chain, we confirm that lead times are

stochastic and can be modeled by a sequence of independent identically distributed random

variables. This underlines the need to further study supply chains with stochastic lead times

and model the behavior of such chains.

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Authors and Affiliations

Peter Nielsen
Zbigniew Michna

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