Zeszyty czasopisma

Tom 59 (2022): Zeszyt 4 (August 2022)

Tom 59 (2022): Zeszyt 3 (June 2022)

Tom 59 (2022): Zeszyt s3 (June 2022)

Tom 59 (2022): Zeszyt 2 (April 2022)

Tom 59 (2022): Zeszyt 1 (February 2022)

Tom 58 (2021): Zeszyt 6 (December 2021)

Tom 58 (2021): Zeszyt 5 (October 2021)

Tom 58 (2021): Zeszyt 4 (August 2021)

Tom 58 (2021): Zeszyt 3 (June 2021)

Tom 58 (2021): Zeszyt 2 (April 2021)

Tom 58 (2021): Zeszyt 1 (February 2021)

Tom 57 (2020): Zeszyt 6 (December 2020)

Tom 57 (2020): Zeszyt 5 (October 2020)

Tom 57 (2020): Zeszyt 4 (August 2020)

Tom 57 (2020): Zeszyt 3 (June 2020)

Tom 57 (2020): Zeszyt 1-2 (April 2020)

Tom 56 (2019): Zeszyt 6 (December 2019)

Tom 56 (2019): Zeszyt 5 (October 2019)

Tom 56 (2019): Zeszyt 4 (August 2019)

Tom 56 (2019): Zeszyt 3 (June 2019)

Tom 56 (2019): Zeszyt 2 (April 2019)

Tom 56 (2019): Zeszyt 1 (February 2019)

Tom 55 (2018): Zeszyt 6 (December 2018)

Tom 55 (2018): Zeszyt 5 (October 2018)

Tom 55 (2018): Zeszyt 4 (August 2018)

Tom 55 (2018): Zeszyt 3 (June 2018)

Tom 55 (2018): Zeszyt 2 (April 2018)

Tom 55 (2018): Zeszyt 1 (February 2018)

Tom 54 (2017): Zeszyt 6 (December 2017)

Tom 54 (2017): Zeszyt 5 (October 2017)

Tom 54 (2017): Zeszyt 4 (August 2017)

Tom 54 (2017): Zeszyt 3 (June 2017)

Tom 54 (2017): Zeszyt 2 (April 2017)

Tom 54 (2017): Zeszyt 1 (February 2017)

Tom 53 (2016): Zeszyt 6 (December 2016)

Tom 53 (2016): Zeszyt 5 (October 2016)

Tom 53 (2016): Zeszyt 4 (August 2016)

Tom 53 (2016): Zeszyt 3 (June 2016)

Tom 53 (2016): Zeszyt 2 (April 2016)

Tom 53 (2016): Zeszyt 1 (February 2016)

Tom 52 (2015): Zeszyt 6 (December 2015)

Tom 52 (2015): Zeszyt 5 (October 2015)

Tom 52 (2015): Zeszyt 4 (August 2015)

Tom 52 (2015): Zeszyt 3 (June 2015)

Tom 52 (2015): Zeszyt 2 (April 2015)

Tom 52 (2015): Zeszyt 1 (February 2015)

Tom 51 (2014): Zeszyt 6 (December 2014)

Tom 51 (2014): Zeszyt 5 (October 2014)

Tom 51 (2014): Zeszyt 4 (August 2014)

Tom 51 (2014): Zeszyt 3 (June 2014)

Tom 51 (2014): Zeszyt 2 (April 2014)

Tom 51 (2014): Zeszyt 1 (February 2014)

Tom 50 (2013): Zeszyt 6 (December 2013)

Tom 50 (2013): Zeszyt 5 (October 2013)

Tom 50 (2013): Zeszyt 4 (August 2013)

Tom 50 (2013): Zeszyt 3 (June 2013)

Tom 50 (2013): Zeszyt 2 (April 2013)

Tom 50 (2013): Zeszyt 1 (February 2013)

Tom 49 (2012): Zeszyt 6-II (December 2012)

Tom 49 (2012): Zeszyt 6-I (December 2012)

Tom 49 (2012): Zeszyt 5 (October 2012)

Tom 49 (2012): Zeszyt 4 (August 2012)

Tom 49 (2012): Zeszyt 2 (April 2012)

Tom 49 (2012): Zeszyt 1 (February 2012)

Tom 48 (2011): Zeszyt 6 (December 2011)

Tom 48 (2011): Zeszyt 5 (October 2011)

Tom 48 (2011): Zeszyt 4 (August 2011)

Tom 48 (2011): Zeszyt 3 (June 2011)

Tom 48 (2011): Zeszyt 2 (April 2011)

Tom 48 (2011): Zeszyt 1 (February 2011)

Tom 47 (2010): Zeszyt 6 (December 2010)

Tom 47 (2010): Zeszyt 5 (October 2010)

Tom 47 (2010): Zeszyt 4 (August 2010)

Tom 47 (2010): Zeszyt 3 (June 2010)

Tom 47 (2010): Zeszyt 2 (April 2010)

Tom 47 (2010): Zeszyt 1 (February 2010)

Tom 46 (2009): Zeszyt 6 (December 2009)

Tom 46 (2009): Zeszyt 5 (October 2009)

Tom 46 (2009): Zeszyt 4 (August 2009)

Tom 46 (2009): Zeszyt 3 (June 2009)

Tom 46 (2009): Zeszyt 2 (April 2009)

Tom 46 (2009): Zeszyt 1 (February 2009)

Tom 45 (2008): Zeszyt 6 (December 2008)

Tom 45 (2008): Zeszyt 5 (October 2008)

Tom 45 (2008): Zeszyt 4 (August 2008)

Tom 45 (2008): Zeszyt 3 (June 2008)

Tom 45 (2008): Zeszyt 2 (April 2008)

Tom 45 (2008): Zeszyt 1 (February 2008)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2255-8896
Pierwsze wydanie
18 Mar 2008
Częstotliwość wydawania
6 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 55 (2018): Zeszyt 1 (February 2018)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2255-8896
Pierwsze wydanie
18 Mar 2008
Częstotliwość wydawania
6 razy w roku
Języki
Angielski

Wyszukiwanie

7 Artykułów
access type Otwarty dostęp

Smart City Through a Flexible Approach to Smart Energy

Data publikacji: 24 Mar 2018
Zakres stron: 3 - 14

Abstrakt

Abstract

The paper provides an overview of the development trends of the smart city. Over the past decades, the trend of the new urban model called smart city has been gaining momentum, which is an aggregate of the latest technologies, intelligent administration and conscious citizens, which allows the city to actively develop, and effectively and efficiently solve the problems it is facing. Profound changes are also taking place in the energy sector. Researchers and other specialists offer a wide variety of innovative solutions and approaches for the concepts of intelligent cities. The paper reviews and analyses the existing methodological solutions in the field of power industry, as well as provides recommendations how to introduce the common platform on the basis of disparate sources of information on energy resources existing in the city as an optimal solution for developing the city's intelligence, flexibility and sustainability based on its starting conditions.

Słowa kluczowe

  • energy management
  • multi-energy city
  • smart city
  • smart city model
  • smart energy city
  • platformization
access type Otwarty dostęp

Optimisation of Combined Cycle Gas Turbine Power Plant in Intraday Market: Riga CHP-2 Example

Data publikacji: 24 Mar 2018
Zakres stron: 15 - 21

Abstrakt

Abstract

In the research, the influence of optimised combined cycle gas turbine unit – according to the previously developed EM & OM approach with its use in the intraday market – is evaluated on the generation portfolio. It consists of the two combined cycle gas turbine units. The introduced evaluation algorithm saves the power and heat balance before and after the performance of EM & OM approach by making changes in the generation profile of units. The aim of this algorithm is profit maximisation of the generation portfolio. The evaluation algorithm is implemented in multi-paradigm numerical computing environment MATLab on the example of Riga CHP-2. The results show that the use of EM & OM approach in the intraday market can be profitable or unprofitable. It depends on the initial state of generation units in the intraday market and on the content of the generation portfolio.

Słowa kluczowe

  • conventional generation
  • EM & OM approach
  • generation portfolio
  • intraday market
access type Otwarty dostęp

Consistency Analysis and Data Consultation of Gas System of Gas-Electricity Network of Latvia

Data publikacji: 24 Mar 2018
Zakres stron: 22 - 34

Abstrakt

Abstract

In the present research, the main critical points of gas transmission and storage system of Latvia have been determined to ensure secure and reliable gas supply among the Baltic States to fulfil the core objectives of the EU energy policies.

Technical data of critical points of the gas transmission and storage system of Latvia have been collected and analysed with the SWOT method and solutions have been provided to increase the reliability of the regional natural gas system.

Słowa kluczowe

  • Baltic countries
  • capacity of pipelines
  • critical points
  • reliability
  • gas storage system
  • security
  • gas transmision system
access type Otwarty dostęp

The Effect of Fuel Quality on Carbon Dioxide and Nitrogen Oxide Emissions, While Burning Biomass and RDF

Data publikacji: 24 Mar 2018
Zakres stron: 35 - 43

Abstrakt

Abstract

The article analyses the variations in carbon dioxide emission factor depending on parameters characterising biomass and RDF (refuse-derived fuel). The influence of moisture, ash content, heat of combustion, carbon and nitrogen content on the amount of emission factors has been reviewed, by determining their average values. The options for the improvement of the fuel to result in reduced emissions of carbon dioxide and nitrogen oxide have been analysed. Systematic measurements of biomass parameters have been performed, by determining their average values, seasonal limits of variations in these parameters and their mutual relations. Typical average values of RDF parameters and limits of variations have been determined.

Słowa kluczowe

  • ash content
  • biomass
  • carbon content
  • carbon dioxide
  • emissions
  • heat of combustion
  • moisture
  • nitrogen oxides
  • refuse-derived fuel
access type Otwarty dostęp

Sustainable Construction Industry Development and Green Buildings: A Case of Latvia

Data publikacji: 24 Mar 2018
Zakres stron: 44 - 52

Abstrakt

Abstract

Nowadays, more and more attention is being paid to the country's economy, construction industry and real estate market's sustainable development and to the studies related to these issues. The aim of the research is to analyse significant aspects of sustainable development of construction activities and real estate market, with particular focus on environmental aspects of construction or the role of green buildings. The research includes an integrated approach of construction industry analysis and analysis of real estate operations area. Scientific and practical solutions and recommendations will enable the industry participants to be introduced to the main sustainable aspects of construction industry development, which, in their turn, can improve the overall performance of the industry in the long term.

Słowa kluczowe

  • construction
  • energy efficiency
  • environment
  • sustainable real estate market development
access type Otwarty dostęp

Highly Reconfigurable Beamformer Stimulus Generator

Data publikacji: 24 Mar 2018
Zakres stron: 53 - 63

Abstrakt

Abstract

The present paper proposes a highly reconfigurable beamformer stimulus generator of radar antenna array, which includes three main blocks: settings of antenna array, settings of objects (signal sources) and a beamforming simulator. Following from the configuration of antenna array and object settings, different stimulus can be generated as the input signal for a beamformer. This stimulus generator is developed under a greater concept with two utterly independent paths where one is the stimulus generator and the other is the hardware beamformer. Both paths can be complemented in final and in intermediate steps as well to check and improve system performance. This way the technology development process is promoted by making each of the future hardware steps more substantive. Stimulus generator configuration capabilities and test results are presented proving the application of the stimulus generator for FPGA based beamforming unit development and tuning as an alternative to an actual antenna system.

Słowa kluczowe

  • antenna array
  • beamforming
  • LabVIEW
  • simulation
  • stimulus generator
access type Otwarty dostęp

An Ice Track Equipped with Optical Sensors for Determining the Influence of Experimental Conditions on the Sliding Velocity

Data publikacji: 24 Mar 2018
Zakres stron: 64 - 75

Abstrakt

Abstract

The ability to slide on ice has previously focused on the measurement of friction coefficient rather than the actual sliding velocity that is affected by it. The performance can only be directly measured by the sliding velocity, and therefore the objective was to design and setup a facility to measure velo-city, and determine how experimental conditions affect it. Optical sensors were placed on an angled ice track to provide sliding velocity measurements along three sections and the velocity for the total sliding distance. Experimental conditions included the surface roughness, ambient temperature and load. The effect of roughness was best reported with a Criterion of Contact that showed a similar sliding velocity for metal blocks abraded with sand paper smoother than 600 grit. Searching for the effect of temperature, the highest sliding velocity coincided with the previously reported lowest coefficient of ice friction. Load showed the greatest velocity increase at temperatures closer to the ice melting point suggesting that in such conditions metal block overcame friction forces more easily than in solid friction. Further research needs to be conducted on a longer ice track, with larger metal surfaces, heavier loads and higher velocities to determine how laboratory experiments can predict real-life situations.

Słowa kluczowe

  • ice friction
  • inclined plane
  • measurement approach
  • sliding on ice
  • sliding velocity
  • surface roughness
7 Artykułów
access type Otwarty dostęp

Smart City Through a Flexible Approach to Smart Energy

Data publikacji: 24 Mar 2018
Zakres stron: 3 - 14

Abstrakt

Abstract

The paper provides an overview of the development trends of the smart city. Over the past decades, the trend of the new urban model called smart city has been gaining momentum, which is an aggregate of the latest technologies, intelligent administration and conscious citizens, which allows the city to actively develop, and effectively and efficiently solve the problems it is facing. Profound changes are also taking place in the energy sector. Researchers and other specialists offer a wide variety of innovative solutions and approaches for the concepts of intelligent cities. The paper reviews and analyses the existing methodological solutions in the field of power industry, as well as provides recommendations how to introduce the common platform on the basis of disparate sources of information on energy resources existing in the city as an optimal solution for developing the city's intelligence, flexibility and sustainability based on its starting conditions.

Słowa kluczowe

  • energy management
  • multi-energy city
  • smart city
  • smart city model
  • smart energy city
  • platformization
access type Otwarty dostęp

Optimisation of Combined Cycle Gas Turbine Power Plant in Intraday Market: Riga CHP-2 Example

Data publikacji: 24 Mar 2018
Zakres stron: 15 - 21

Abstrakt

Abstract

In the research, the influence of optimised combined cycle gas turbine unit – according to the previously developed EM & OM approach with its use in the intraday market – is evaluated on the generation portfolio. It consists of the two combined cycle gas turbine units. The introduced evaluation algorithm saves the power and heat balance before and after the performance of EM & OM approach by making changes in the generation profile of units. The aim of this algorithm is profit maximisation of the generation portfolio. The evaluation algorithm is implemented in multi-paradigm numerical computing environment MATLab on the example of Riga CHP-2. The results show that the use of EM & OM approach in the intraday market can be profitable or unprofitable. It depends on the initial state of generation units in the intraday market and on the content of the generation portfolio.

Słowa kluczowe

  • conventional generation
  • EM & OM approach
  • generation portfolio
  • intraday market
access type Otwarty dostęp

Consistency Analysis and Data Consultation of Gas System of Gas-Electricity Network of Latvia

Data publikacji: 24 Mar 2018
Zakres stron: 22 - 34

Abstrakt

Abstract

In the present research, the main critical points of gas transmission and storage system of Latvia have been determined to ensure secure and reliable gas supply among the Baltic States to fulfil the core objectives of the EU energy policies.

Technical data of critical points of the gas transmission and storage system of Latvia have been collected and analysed with the SWOT method and solutions have been provided to increase the reliability of the regional natural gas system.

Słowa kluczowe

  • Baltic countries
  • capacity of pipelines
  • critical points
  • reliability
  • gas storage system
  • security
  • gas transmision system
access type Otwarty dostęp

The Effect of Fuel Quality on Carbon Dioxide and Nitrogen Oxide Emissions, While Burning Biomass and RDF

Data publikacji: 24 Mar 2018
Zakres stron: 35 - 43

Abstrakt

Abstract

The article analyses the variations in carbon dioxide emission factor depending on parameters characterising biomass and RDF (refuse-derived fuel). The influence of moisture, ash content, heat of combustion, carbon and nitrogen content on the amount of emission factors has been reviewed, by determining their average values. The options for the improvement of the fuel to result in reduced emissions of carbon dioxide and nitrogen oxide have been analysed. Systematic measurements of biomass parameters have been performed, by determining their average values, seasonal limits of variations in these parameters and their mutual relations. Typical average values of RDF parameters and limits of variations have been determined.

Słowa kluczowe

  • ash content
  • biomass
  • carbon content
  • carbon dioxide
  • emissions
  • heat of combustion
  • moisture
  • nitrogen oxides
  • refuse-derived fuel
access type Otwarty dostęp

Sustainable Construction Industry Development and Green Buildings: A Case of Latvia

Data publikacji: 24 Mar 2018
Zakres stron: 44 - 52

Abstrakt

Abstract

Nowadays, more and more attention is being paid to the country's economy, construction industry and real estate market's sustainable development and to the studies related to these issues. The aim of the research is to analyse significant aspects of sustainable development of construction activities and real estate market, with particular focus on environmental aspects of construction or the role of green buildings. The research includes an integrated approach of construction industry analysis and analysis of real estate operations area. Scientific and practical solutions and recommendations will enable the industry participants to be introduced to the main sustainable aspects of construction industry development, which, in their turn, can improve the overall performance of the industry in the long term.

Słowa kluczowe

  • construction
  • energy efficiency
  • environment
  • sustainable real estate market development
access type Otwarty dostęp

Highly Reconfigurable Beamformer Stimulus Generator

Data publikacji: 24 Mar 2018
Zakres stron: 53 - 63

Abstrakt

Abstract

The present paper proposes a highly reconfigurable beamformer stimulus generator of radar antenna array, which includes three main blocks: settings of antenna array, settings of objects (signal sources) and a beamforming simulator. Following from the configuration of antenna array and object settings, different stimulus can be generated as the input signal for a beamformer. This stimulus generator is developed under a greater concept with two utterly independent paths where one is the stimulus generator and the other is the hardware beamformer. Both paths can be complemented in final and in intermediate steps as well to check and improve system performance. This way the technology development process is promoted by making each of the future hardware steps more substantive. Stimulus generator configuration capabilities and test results are presented proving the application of the stimulus generator for FPGA based beamforming unit development and tuning as an alternative to an actual antenna system.

Słowa kluczowe

  • antenna array
  • beamforming
  • LabVIEW
  • simulation
  • stimulus generator
access type Otwarty dostęp

An Ice Track Equipped with Optical Sensors for Determining the Influence of Experimental Conditions on the Sliding Velocity

Data publikacji: 24 Mar 2018
Zakres stron: 64 - 75

Abstrakt

Abstract

The ability to slide on ice has previously focused on the measurement of friction coefficient rather than the actual sliding velocity that is affected by it. The performance can only be directly measured by the sliding velocity, and therefore the objective was to design and setup a facility to measure velo-city, and determine how experimental conditions affect it. Optical sensors were placed on an angled ice track to provide sliding velocity measurements along three sections and the velocity for the total sliding distance. Experimental conditions included the surface roughness, ambient temperature and load. The effect of roughness was best reported with a Criterion of Contact that showed a similar sliding velocity for metal blocks abraded with sand paper smoother than 600 grit. Searching for the effect of temperature, the highest sliding velocity coincided with the previously reported lowest coefficient of ice friction. Load showed the greatest velocity increase at temperatures closer to the ice melting point suggesting that in such conditions metal block overcame friction forces more easily than in solid friction. Further research needs to be conducted on a longer ice track, with larger metal surfaces, heavier loads and higher velocities to determine how laboratory experiments can predict real-life situations.

Słowa kluczowe

  • ice friction
  • inclined plane
  • measurement approach
  • sliding on ice
  • sliding velocity
  • surface roughness

Zaplanuj zdalną konferencję ze Sciendo