Browse

You are looking at 1 - 10 of 562 items for :

  • Process Engineering and Industrial Engineering x
Clear All
Open access

Michat Grendaa

Abstract

Demand for thin-walled structures has been increasing for many years. Cold- formed, thin-walled channel beams are the subject of presented research. The local elastic buckling and limit load of these beams subjected to pure bending are investigated. This study includes numerical investigation called the Finite Strip Method (FSM). The presented results give a deep insight into behaviour of such beams and may be used to validate analytical models. The number of works devoted to the theory of thin-walled structures has been steadily growing in recent years. It means that is an increasing interest in practical methods of manufacturing cold-formed thin-walled beams with complicated cross-sections, including also beams with web stiffeners. The ratio of transverse dimensions of beam to its wall-thickness is high, therefore, thin-walled beams are prone to local buckling that may interact with other buckling modes. The stability constraints should be always considered when using cold-formed thin-walled beams.

Open access

Pjotrs Trifonovs-Bogdanovs and Anvar Zabirov

Abstract

Analysis and simulation of the Strapdown Inertial Navigation System (SINS) error genesis revealed that the East Feedback Contour has the greatest influence on the development of an error in this model, and angular velocity sensor Δω𝒚 is the critical element. In order to prevent the development of an error, structural correction in the East Feedback Contour, and elements that are more critical, namely in angular velocity measurement sensors is the best option.

Open access

Ivana Cechova, Joanna Bartnicka and Luboslav Dulina

Abstract

Musculoskeletal complaints represent a common occupational problem for health care workers throughout the world. This study provides shortened results of review by Nordic Questionnaire, which was modified for review reasons. The aim of the study is verification of work-related load Slovak and Polish nurses in their work and mutual comparison of the results. Comparison of statistical sample of Slovak nurses (468) and Polish nurses (48 for this moment) points to certain common features in the field of pain and the determination of their causes. Verification of the knowledge base of nurses in the field of ergonomics, principles of manipulation of load and kinestetika shows slightly better results for Polish nurses. The study will continue to compare larger statistical samples, identify the most common pains and their causes to the reason prevent them.

Open access

Dorota Klimecka-Tatar and Katarzyna Kapustka

Abstract

The visual management technique used in process improvement, i.e. value stream mapping (VSM) has been presented in the paper. Value stream mapping is one of the basic management tools in the context of Lean Management or Lean Production. It allows to visualize the flow of decision, information, material and their connections in the full production cycle (from the order, through planning, production, to shipping to the customer). VSM is a lean tool that gives the ability to create flows in the process before implementing changes. In this paper, the possibilities of changes planning based on the current and future status maps have been discussed. On the basis of the current state map (CSM), the areas requiring improvement and operations which efficiency is decisive and for the process have been designated. Particular attention has been paid to the possibilities of using VSM in unit production processes. In the paper has been proposed the two possibilities for company development in terms of the improvement technique in line with the Kaizen philosophy as well as the implementation of process innovations. Which means balanced development through the improvement of the existing process or an acute development strategy through the implementation of process innovations (which involves significant costs).

Open access

Leszek Chybowski

Abstract

The article describes a method for analyzing and solving problem situations with the use of Su-Field models and 76 inventive standards. These tools are part of the “Theory of Inventive Problem Solving”. The author has presented the basic concepts of Su-Field models, including in the compilation of the most commonly used substances their fields and types of interactions in Su-Field models. The inventive standards have also been presented and grouped. Attempts have been made to solve two undesirable situations that occur during the operation of a complex technical system, which is the fuel injector of the self-ignition engine. Problem situations related to insufficient impact were modelled - too low tightening of the injector spring, and negative (harmful) interaction - erosive wear of the holes in the atomizer nozzle. Using the inventive standards of Class-1 and Class-2, general solutions to these problems have been found. After the transformation, exemplary detailed ways of solving the aforementioned problems have been presented in order to improve the design of the injector for these models. A summary and comments on the applicability of the presented methodology, regarding such complex technical systems, have also been presented.

Open access

Dariusz Tarnapowicz

Abstract

The increase of energy efficiency in autonomous marine generating sets improves the overall efficiency of the ship’s propulsion. One of the methods to increase the efficiency of generating sets is the use of synchronous machines with permanent magnets in sets as generators (PMSG). The use of PMSG in connected with the need to install power converters in order to maintain constant parameters of the supply voltage and the possibility of reactive power’s distribution between generating sets that work in parallel. The article presents the possibility of using transformer multi-level inverters in parallel operation of marine generating sets with PMSG. On the basis of the results of simulation tests, the theoretical assumptions for the possibilities of active and passive power adjustment in the parallel operation of generating sets were confirmed.

Open access

Kinga Stecuła and Mikheil Chikhradze

Abstract

The article presents a proposal of use a decision table to support the decision-making process in scope of maintenance management in mining companies. In particular, it refers to decisions related to evaluation and improvement of mining machinery use in the mining production process. The article presents the theoretical foundations of decision tables building and characteristics of the most important stages of creating this table. This whole process was tried to refer specifically the mining industry. For this reason, during construction of the decision tables, the results of research on the effectiveness of the selected mining machines were used. The conducted research provided a lot of data, information and knowledge on the work of the particular mining machines, especially regarding the number and reasons for unplanned breaks during the machines’ work. The developed decision table will consist of conditions, rules and actions whose purpose is to define the recommendations for the particular groups of participants in the mining production process. The obtained results will form the basis for the development of the recommendations and proposals of actions to improve the level of use of mining machines. The authors focused mainly on the practical use of tables to support the decision-making process regarding maintenance and improvement of effectiveness of mining machines. The obtained results confirm the validity of the adopted assumptions. Decision tables can become an important tool that supports the decision-making process within mining companies.

Open access

Aneta Włodarczyk and Marta Kadłubek

Abstract

Tightening the environmental norms that result from the priorities of the EU 2030 Energy and Climate Package and the reform of the EU ETS have caused the necessity to implement an effective system of managing the risk of carbon dioxide emission and integrate it with the existing enterprise management system. Evaluation of the direction and strength of correlation between EUA price changes and energy companies stock price returns is crucial from point of view the managerial staff making proper decisions about the use of the CO2 emission permits by energy companies. It is an important stage of carbon emission risk management process. The aim of this paper is to verify the possibility of use the multifactor models with GARCH structure as a tool supporting the carbon emission management process in energy companies. Empirical analysis is connected with the estimation of multifactor models with GARCH structure in the Phase II and Phase III of the EU ETS functioning for two groups of Polish energy companies: group of the Respect Index companies and others. Such an approach allows to check whether the Respect Index companies are more robust than others on the carbon emission risk, in particular the EUA price risk associated with the intensification works on modifying the EU ETS functioning. We found that the impact of EUA price changes on energy companies stock returns and their volatility is statistically insignificant in case of all Respect Index companies.