Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 19
items per page: 25 50 75
Sort by:

Abstract

Pre-treatment techniques employed for exhaust emission control of compression ignition engines were found to reduce the emission levels by small percentage only, failing to meet the required emission regulations. Post-treatment technique including diesel particulate filtration, diesel oxidation catalysis and selective catalytic reduction is found to be an effective solution. While the fuel-based regeneration of diesel particulate filter leads to uncontrolled combustion affecting the durability of the filter. Development of an effective regeneration system is one of the major technical challenges faced by automotive industry for meeting emission norms. A composite regeneration system with the application of microwave energy is proposed in this paper. As an initial phase, a three-dimensional model of the system is developed and its flow analysis is carried out by considering the case of single channel flow. Simulation of the regeneration process is also done by developing a Simulink model. The results of simulation showed that an engine running continuously for a period of 24 hours would require three regenerations.
Go to article

Abstract

The authors presented problems related to utilization of exhaust gases of the gas turbine unit for production of electricity in an Organic Rankine Cycle (ORC) power plant. The study shows that the thermal coupling of ORC cycle with a gas turbine unit improves the efficiency of the system. The undertaken analysis concerned four the so called "dry" organic fluids: benzene, cyclohexane, decane and toluene. The paper also presents the way how to improve thermal efficiency of Clausius-Rankine cycle in ORC power plant. This method depends on applying heat regeneration in ORC cycle, which involves pre-heating the organic fluid via vapour leaving the ORC turbine. As calculations showed this solution allows to considerably raise the thermal efficiency of Clausius-Rankine cycle.
Go to article

Abstract

The small scale green areas, urban parks, urban forests or natural green areas are vital components of the urban structure of cities. This paper, using examples from Bratislava, analyzes the successful and lost opportunities to apply the concept of green space as a strategy for urban regeneration and development, and discusses the ways to incorporate this concept in the teaching and educational practices in the fields of urbanism and landscape architecture.
Go to article

Abstract

Introduction: Platelet-rich plasma (PRP) preparations can be used in bone tissue healing but there are numerous doubts among clinical orthopedists about effectiveness of this method. Materials and methods: The studies were carried out in 12 rabbits of white termond breed. In operating room we operationally generated cylindrical, unicortical defects of the diameter of 4 mm in the middle of the shafts of both femurs. The defects in the left bones were left without filling and served as controls, and 0.7 ml of the ready-to-use PRP was administered to the defects in the right bones (experimental group). We evaluated the usefulness of the diagnostic methods applied: biomechanical tests, micro-CT tests, densitometry, typical radiology, macroscopic measurements, histopathological examinations. Results: The macroscopic measurements showed a statistically significant increase in the dimension in the area of the right defect filled with PRP in relation to the control group. In experimented group, the assessment of the X-ray images showed the formation of a callus cuff around the defects. Densitometric examinations showed no statistically significant differences between defects in the experimental and control group. The analysis of the micro-CT examina- tions showed an increase in the total volume of the tissue examined (Vb) and the low density tissue fraction (Vb2) in the experimental group. The biomechanical examinations revealed signi- ficant decrease in the maximum breaking force (F max) necessary to break the bone in the experi- mental group in relation to the control group. Conclusions: Platelet-rich plasma (PRP) stimulates bone formation in the area of bone defects and may accelerate bone regeneration.
Go to article

Abstract

Regeneration – an integrated process of activities undertaken in the spatial, social and economic dimensions – should lead to the improvement of the living conditions of inhabitants of degraded urban areas. The European Union in 2007- 2013 allocated financial resources for this purpose in the form of JESSICA initiative which is based on financial engineering mechanism. Experiences gained so far allow conclusions to be drawn that JESSICA is a highly fi nancially-effi cient instrument but, however, not always delivers the desired outcomes in the spatial and social sphere. The scope of projects often is limited to infrastructural investments and does not reflect the complexity of regeneration process. In the article the authors analyse experiences of the five Polish regions with the use of JESSICA, point out main problems and formulate recommendations for sustainable urban policy.
Go to article

Abstract

Waterfront regeneration of port districts emerge as a tool for prestigious development of cities in urban re-imaging and growth. Creation of prestigious housing in these areas are part of a broader strategy of mixed-use and property-led development, but in absence of a holistic approach in planning and design, the urban landscapes may be developed merely on basis of the real estate frameworks. This article looks at how development trends of port cities can take an unintended stance in property-led regeneration of port districts, creating gated communities and failing to succeed in achieving the pre-determined objectives in urban planning. The discussion, which will address to issues of place-making, commodification of public space and planning policies, will take the port city of Izmir as the case. It is suggested that the adoption of a holistic approach to urban planning should guide the regeneration processes and design should take place-making into consideration.
Go to article

Abstract

Art. 52 sec. 1 of the Regeneration Act of 9 October 2015 allowed municipalities which, at the time of its entry into force, did not have a valid revitalization program, to carry out revitalization activities on the basis of a revitalization program other than the municipal revitalization program. The choice of procedure was left by the legislature of the municipality, assuming that at the initial stage of the implementation of the law, only the municipality should test its instrument, referring to the nature and scale of its needs. The ROP Managing Authority in Małopolska as the only one in the country introduced the requirement of developing municipal revitalization programs for all municipalities that did not have a current revitalization program at the time of the entry into force of the Act. Therefore, these municipalities, in order to benefi t from EU funding under ROP WM 2014-2020 for revitalization activities planned in the programs, were not able to rely on the derogation contained in art. 52 sec. 1 of the Act. Regardless of the size of the municipality and the nature of revitalization needs, they were compelled to develop a document complying with the statutory procedure, the fi rst stage being the delimitation of the degraded area and the revitalization area and confi rmation by the resolution of the municipality council. As a result Małopolskie Voivodeship has become Poland’s largest laboratory of methodology of delimitation of these areas and development of revitalization programs. The aim of the article is to present the diversity of applied methodological approaches to the delimitation of revitalization areas in Małopolskie Voivodeship and to describe the most noteworthy, as well as to indicate the most common errors in the designation of these areas.
Go to article

Abstract

Urban regeneration is driven by many different engines. These engines, however, in some circumstances may appear to turn to either a success or failure factor. In this context, it is appropriate to analyse how factors that serve the regeneration process are affected by embedding research in a particular paradigm set by the theories of so called “regional development”. The choice of these concepts analysed in the article was the result of literature review. The article consists of four parts. The first part defines the development factors and shows how the concentration of negative phenomena in degraded areas may inhibit their optimal use in the context of the city as a whole. Two subsequent chapters analyse how major theories of regional development picture external and internal factors that influence the development of a specific territory. Then, in the summary the author discusses, how main urban and regional development theories reflect the rationale for mitigating barriers in using local development factors as real driving forces of urban regeneration.
Go to article

Abstract

An efficient system for plant regeneration of Senna occidentalis from hypocotyl-derived callus was developed. Callus was induced from leaf and hypocotyl explants on MS medium amended with 9.04 μM 2,4-D + 2.22 μM BAP and 10.74 μM NAA + 2.22 μM BAP. Medium browning due to leaching of compounds from callus was encountered and ameliorated through incorporation of 2.84 μM ascorbic acid. Leaf-derived callus showed no shoot induction ability, while hypocotyl-derived callus produced shoots in all cytokinin-amended treatments and also in combination with 2.68 μM NAA. For shoot formation, BAP-augmented treatments were better than medium with Kin added. Rhizogenesis was better on 1/2 MS basal medium with IBA than in the NAA and IAA treatments. Regenerated plants were acclimatized with 94% survival and showed similar morphology to field-grown plants.
Go to article

Abstract

To understand the molecular mechanism controlling in vitro plant morphogenesis, a culture system enabling induction of alternative morphogenic pathways (somatic embryogenesis, SE; shoot organogenesis, ORG) in a well defined population of somatic cells is needed. Arabidopsis is the most useful model plant for genomic studies, but a system in which SE or ORG can be induced alternatively in the same type of explant has not been proposed. Immature zygotic embryos (IZEs) of Arabidopsis provide the only explants with embryogenic potential, and have been recommended for studying mechanisms of SE induced in vitro. This study was aimed at defining culture conditions promoting induction of alternative morphogenic pathways: shoot ORG in IZE explants. The established protocol involves pretreatment of IZE explants with liquid auxin-rich callus induction (CIM) medium, followed by subculture on solid cytokinin-rich shoot induction medium (SIM). The method enables efficient shoot induction in Columbia (Col-0) and Wassilewskija (Ws), genotypes commonly used in molecular studies. During 3 weeks of culture up to 90% of Col-0 and 70% of Ws explants regenerated shoots via an indirect morphogenic pathway. We analyzed the qRT-PCR expression patterns of the LEC (LEC1, LEC2 and FUS3) genes, the key regulators of Arabidopsis embryogenesis, in the IZE explants induced to promote shoot ORG. The sharp decline of LEC expression on SIM medium confirmed that culture of Arabidopsis IZE explants enables experimental manipulation of the morphogenic response of somatic cells. A scheme illustrating various in vitro morphogenic responses of IZEs in relation to hormonal treatment is presented.
Go to article

Abstract

The objective of the paper is to analyse thermodynamical and operational parameters of the supercritical power plant with reference conditions as well as following the introduction of the hybrid system incorporating ORC. In ORC the upper heat source is a stream of hot water from the system of heat recovery having temperature of 90 °C, which is additionally aided by heat from the bleeds of the steam turbine. Thermodynamical analysis of the supercritical plant with and without incorporation of ORC was accomplished using computational flow mechanics numerical codes. Investigated were six working fluids such as propane, isobutane, pentane, ethanol, R236ea and R245fa. In the course of calculations determined were primarily the increase of the unit power and efficiency for the reference case and that with the ORC.
Go to article

Abstract

In the paper presented is an idea of organic Rankine cycle (ORC) operating with supercritical parameters and so called dry fluids. Discussed is one of the methods of improving the effectiveness of operation of supercritical cycle by application of internal regeneration of heat through the use of additional heat exchanger. The main objective of internal regenerator is to recover heat from the vapour leaving the turbine and its transfer to the liquid phase of working fluid after the circulation pump. In effect of application of the regenerative heat exchanger it is possible to obtain improved effectiveness of operation of the power plant, however, only in the case when the ORC plant is supplied from the so called sealed heat source. In the present paper presented is the discussion of heat sources and on the base of the case study of two heat sources, namely the rate of heat of thermal oil from the boiler and the rate of heat of hot air from the cooler of the clinkier from the cement production line having the same initial temperature of 260 oC, presented is the influence of the heat source on the justification of application of internal regeneration. In the paper presented are the calculations for the supercritical ORC power plant with R365mfc as a working fluid, accomplished has been exergy changes and exergy efficiency analysis with the view to select the most appropriate parameters of operation of the power plant for given parameters of the heat source.
Go to article

Abstract

The purpose of the study was to assess the effect of autologous activated platelet-rich plasma on healing of a bone substitute - tricalcium phosphate hydroxyapatite in experimental long bone defects using an animal model. The experiment involved an animal model of femoral defect. 24 Termond white rabbits were used in the study. We evaluated the effect of autologous platelet-rich plasma on tricalcium phos- phate using classical radiology, micro-CT studies, strength tests and histological evaluation. Radiological and histological assessment did not show a beneficial effect of PRP together with a bone substitute in comparison to filling the defects only with bone replacement material. The only benefit of adding platelet-rich plasma to a bone substitute was shown in microCT imaging. Autologous, activated platelet-rich plasma combined with hydroxyapatite tricalcium phos- phate has a positive effect on the remodeling of the newly formed bone tissue, increasing its density.
Go to article

Abstract

According to the Grant Map of the Ministry of Development (MoD) as of March-April 2017, there were 1716 urban regeneration (revitalization) projects implemented in Poland between 2007-2013. Data from 11 voivodeships (out of 16 regions NUTS 2 in Poland) and 977 projects was sufficient to provide a representative sample (56,9% of projects presented in the Grant Map). The main methods used in the article included observation and review of MoD statistical data and literature on the subject. As observed by the author, between 2007-2013 the definition of urban regeneration (revitalization) was only mentioned in one of the footnotes to the housing guidelines, which was a poor legal basis for the regional managing authorities. Similarly, there was no solid basis in the strategic documents (national) for that period: they did not provide any definition of revitalization. It was in the interest of the beneficiaries, as well as – partly – in the interest of those managing authorities to satisfy the local needs, especially those needs which were not considered the result of the shift to the post-industrial era, but rather as a result of numerous institutional and political events. Due to these features, the period 2007-2013 was dominated by infrastructure projects aimed at the quality of life but also efficient in terms of spending European money. It seems that there was an agreement between regional managing authorities and the benefi ciaries (potential voters) as to the way of spending the revitalization funding. This was understood differently at national level, but because institutions at this level were not involved directly in the urban regeneration (revitalization), their influence on regional units was minor. Even more so because the managing authorities were also interested in speeding up the process of spending European resources.
Go to article

Abstract

This paper examines the conservation master plan prepared for in Beyoglu, Istanbul’s Galata Persembe Bazaar waterfront and its Genoese and Ottoman port heritage. This paper initially contains an analytical perspective. This perspective informs the analyses of the evolution of planning process on the conservation of the port heritage. The results of relations between port heritage and conservation planning works have come up for discussion. Spatial interventions on the Persembe Bazaar waterfront began in the 1980s by removing industrial and commercial buildings in the area. These interventions, made in the framework of wiping away the Halic (Golden Horn) waterfront created pressure for urban regeneration in areas with historical and cultural heritage assets like Persembe Bazaar. Major projects such as Galataport and Halicport on the waterfronts of the Halic and the Bosphorus have increased this pressure. Huge functional transformations on the waterfront are desired along with the Persembe Bazaar Conservation Master Plan, which conforms neither to the content nor the context of general conservation principles or Turkey’s conservation legislation. Its content includes no interventions compatible with the theme of “living in harbour cities” and should thus be criticized. The conservation of the tangible and intangible heritage of historical port features, the preservation and development of the service sector and trade in the area requires adopting a holistic understanding of conservation and taking historical features into account. Such an important port heritage site should not be seen as having only touristic functions. It should emphasize more local features for their daily use of local residents and businesses.
Go to article

Abstract

This article presents the results of scientific investigations on the thermal regeneration process of a sorbent of mineral origin sorbent using a retort burner. Diesel oil, a petroleum liquid, most often pervades the environment during different catastrophes. The investigated sorbent of mineral origin was used in the standard way that the Fire Service removes such petroleum liquids from the environment during disasters. For research purposes, a regeneration chamber with a retort burner was constructed. The first phase of the investigation was aimed at defining the physico-chemical features of the sorbent after subsequent cycles of the regeneration process. The second phase involved an analysis of the energy and ecological effects of the regeneration process. The results showed that the first three cycles of the regeneration process occurred under low emission conditions. The proposed regeneration method achieved a positive energetic effect with a functional heat stream with an average value of 12.4 kW (average efficiency of the regeneration chamber was 68 %). The method is very efficient, with regeneration rates between 7.2 kg/h and 8.4 kg/h. It requires only a short amount of time for the start-up and extinction of the regeneration chamber, and it is also flexible to changes in the process conditions.
Go to article

Abstract

The paper presents an efficiency analysis of two transcritical CO2 power cycles with regenerative heaters. For the proposed cycles, calculations of thermal efficiency are given for selected values of operating parameters. It was assumed that the highest working temperature and pressure are in the range from 600 to 700 °C and 40 to 50 MPa, respectively. The purpose of the calculations was optimization of the pressure and mass flows in the regenerative heaters to achieve maximum cycle efficiency. It follows that for the assumed upper CO2 parameters, efficiency of 51-54% can be reached, which is comparable to the efficiency of a supercritical advanced power cycle considered by Dostal.
Go to article

Abstract

The paper presents a review of concepts for the development of city centres in response to social and culture processes, economic, technical and environmental developments taking place at present on those areas. This review proves that concepts tend to change over time from those based on economic dynamics to those based on collaborative commons and on governance. On the example of a few city centres situated in the Silesian Region an analysis was carried out of the concepts being presently applied and with the use of which projects Silesian cities strive to maintain and strengthen the dynamics and vitality of city centres.
Go to article

Abstract

This article analyzes the social content of spatial order concept and manifestations of social participation in shaping this order using two examples: shaping the safety of public spaces and revitalizing cities. The author concludes with proposals to increase public participation in the creation of spatial order.
Go to article

This page uses 'cookies'. Learn more