In this article, a comparison of economic effectiveness of various heating systems dedicated to residential applications is presented: a natural gas-fueled micro-cogeneration (micro-combined heat and power – μCHP) unit based on a free-piston Stirling engine that generates additional electric energy; and three so-called classical heating systems based on: gas boiler, coal boiler, and a heat pump. Calculation includes covering the demand for electricity, which is purchased from the grid or produced in residential system. The presented analyses are partially based on an experimental investigation. The measurements of the heat pump system as well as those of the energy (electricity and heat) demand profiles in the analyzed building were conducted for a single-family house. The measurements of the μCHP unit were made using a laboratory stand prepared for simulating a variable heat demand. The overall efficiency of the μCHP was in the range of 88.6– 92.4%. The amounts of the produced/consumed energy (electricity, heat, and chemical energy of fuel) were determined. The consumption and the generation of electricity were settled on a daily basis. Operational costs of the heat pump system or coal boiler based heating system are lower comparing to the micro-cogeneration, however no support system for natural gas-based μCHP system is included.
The remarkable development of sanitation in Morocco has inevitably led to the production of sludge generated from wastewater treatment plants in increasing quantities. Consequently, the problem of sludge management becomes persistent and worrying.
The aim of this paper was to contribute to the study of sewage sludge management issue in Morocco by identifying the various constraints hampering the sustainable disposal and/or recovery of municipal sewage sludge and drawing up rec-ommendations for the decision-makers. Moreover, in the context of improving by learning from best practices and seeking common solutions regarding this problematic, benchmarking with other countries has been conducted as well.
To carry out this study, a methodological approach was defined based on bibliographic research, surveys, interviews and benchmarking.
The constraints hampering the sustainable management of sludge are numerous and complex, they have not been tech-nical and environmental but also a regulatory, institutional-organizational and economic-financial nature yet. Therefore, municipalities, government and academia ideally would be encouraged to participate in the decision-making process re-garding the management of sewage sludge. Technical solutions, when coupled with stakeholder participation, can lead to policy implementation with a higher chance of improving the present situation.
In the case of Morocco, when comparing with others sludge recovery and disposal routes, land application (reuse in ag-riculture, silviculture and rehabilitation of degraded soils) remains the most environmentally friendly option, as well as a sustainable and economically viable solution.
The smart city concept is becoming more and more popular as a direction for further development of cities in the European Union.
The main goal of the article is to determine the relationship between the concept of a smart city and the competitiveness of a modern city, understood as a standard of living of city’s inhabitants. The research method is a case study, based on a selected example of the city of Mannheim in Germany.
The author assumes that the results of the research, in addition to the contribution to the still developing knowledge on smart cities, will be able to fulfill the practical task – support the development and increase of competitiveness of contemporary Polish cities.
The present paper describes a cycle, which may be applied in sewage treatment plants as a system to convert biological waste into process heat and electricity. In sludge stabilization processes anaerobic fermentation acts as the source of methane, which can be used then to generate heat and electric current in gas turbines. Products of high-temperature oxidation can be utilized in organic Rankine cycles to generate electric power. Waste heat is used for heating the fermenting biomass. Energy balance equations mentioned in the thesis: organic Rankine cycle, regenerative gas turbine engine, anaerobic sludge stabilization system.
The reason for undertaking this study was to determine the possible involvement of natural convection in the global heat transfer, that occurs in the heated steel rods bed. This problem is related to the setting of the effective thermal conductivity of the bars bed. This value is one of the boundary conditions for heating modeling of steel rods bundles during heat treatment. The aim of this study was to determine for which geometry of the bed bars, there will be no free convection. To analyze the problem the Rayleigh criterion was used. It was assumed that for the value of the number Ra < 1700 convection in the bed bars does not occur. For analysis, the results of measurements of the temperature distribution in the unidirectionally heated beds of bars were used. It has been shown, that for obtained, during the test, differences of temperature between the surfaces of adjacent rods, convection can occur only when the diameter of the rod exceeds 18 mm.
The manufacture and consumption of market products show ever growing trends, and this means not only the supply and demand volume but also, to a higher and higher extent, searching for new products distinguishable from the variety of products on the market. Thus, it is necessary to find methods of functional, logical and structural combination of the so far existing engineering applications like CAx, RP/RT/RE, PDM/TDM, PPC/ERP, CE/SE and RDBMS techniques. A new challenge imposed on manufacturers by the competitive market is the so-called “product customization”, i.e. attending to an individual customer’s requirements in the features of a series manufactured product. The general objective of customisation is to elaborate features of a product, manufacturing processes, documentation and production organisation in such a way that the product’s individual features meet the customer’s requirements and its manufacturing process, price and service do not stray from series manufactured products.
The paper aims to analyse the relationship between the city space and the art present in public spaces and narrative located therein. Analysis of selected examples of contemporary art in urban space and literature allows the conclusion, that interdisciplinary narrativity descending from a literary work, allows for the transfer of meanings from public art objects to the city space and individual narratives of recipients. Not just the meanings, that the artists intend to convey, but also the meanings individually interpreted by those, who observe the work.
This article discusses the challenges and problems caused by predatory journals in scholarly communication. By focusing on the editorial practices, I describe the case of Dr. Anna Fraud (Anna O. Szust in Polish): a bogus scientist created by four Polish scholars. Dr. Fraud became a member of editorial boards in over 40 scientific journals although she is a fake person and, obviously has no experience in journal editing. The present paper aims to show that scientist always have to care about a quality control and a peer review system. The article concludes with a presentation of the ‘Think. Check. Submit’ Initiative which provides useful and helpful tools for analysing journals by potential contributors.
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