The national ecolabel of tourist accommodation establishments and rural tourism enterprises of Latvia – the ‘Green Certificate’ (hereinafter the ‘Green Certificate’) celebrated its 20th anniversary in 2019. Its creation in 1999 was initiated by the Latvian Rural Tourism Association ‘Baltic Country Holidays’, and it is currently one of the oldest European ecolabels still in operation. One of the most significant tourism and rural tourism resources in Latvia is the natural and cultural heritage, which is the basis for the development of rural tourism products. In this process, ecosystem services used in tourism products play a major role. One of the goals of the ‘Green Certificate’ is environment, nature and local society friendly and sustainable farming, which means both a careful use of natural resources and their inclusion in the tourism product development process. The aim of this study was to find out which ecosystem services were used and the ways they were used by rural tourism companies to create the nature protection, social and economic added value. According to the respondents, 1/3 of the revenue of the ‘Green Certificate’ companies is generated by the use of the ecosystem services. It is an argument for further research on the possibilities of the ecosystem services to be used more effectively in future in developing new rural tourism products.

The national ecolabel of tourist accommodation establishments and rural tourism enterprises of Latvia – the ‘Green Certificate’ (hereinafter the ‘Green Certificate’) celebrated its 20ᵗʰ anniversary in 2019. Its creation in 1999 was initiated by the Latvian Rural Tourism Association ‘Baltic Country Holidays’, and it is currently one of the oldest European ecolabels still in operation. One of the most significant tourism and rural tourism resources in Latvia is the natural and cultural heritage, which is the basis for the development of rural tourism products. In this process, ecosystem services used in tourism products play a major role. One of the goals of the ‘Green Certificate’ is environment, nature and local society friendly and sustainable farming, which means both a careful use of natural resources and their inclusion in the tourism product development process. The aim of this study was to find out which ecosystem services were used and the ways they were used by rural tourism companies to create the nature protection, social and economic added value. According to the respondents, 1/3 of the revenue of the ‘Green Certificate’ companies is generated by the use of the ecosystem services. It is an argument for further research on the possibilities of the ecosystem services to be used more effectively in future in developing new rural tourism products.

In the market of the Latvia different wood surface coating materials suitable for use in outdoor conditions are offered, but available information on the efficiency of these against direct water exposure is insufficient. For structural timber building elements, such as glued laminated timber (GLT), the surface coating should be applied taking into account technological, visual or colour changes (ISO 7724:1984) and – last, but not least – economic aspects are considered. Wood surfaces coated with coating materials, such as varnishes, paints, etc. can stabilize some properties such as movement of moisture content, dimensional changes and attack by microorganisms and fungi. The changes in the moisture content of timber may influence such important parameters as mechanical properties and the total life time of the structural timber elements. A study has been conducted with the aim of assessing the efficiency of coating materials used for wood protection against water absorption. In this study, six different commercial coating products used for the treatment of spruce (Picea Abies L. Karst.) and pine (Pinus Sylvestris L.) samples were tested. The efficiency of different coating substances was assessed using two modified test methods according to the standards EN 382-2 (1994) and EN 927-5 (2006), determining the surface water absorption after immersion in water for 24 h and the dynamics of water absorption of the glued laminated timber for 696 h kept in water. As a result of the study, it has been ascertained that organic solvent-based commercial coating products are more efficient against short-term and long-term wood water absorption compared to oil-based coating materials.

In the market of the Latvia different wood surface coating materials suitable for use in outdoor conditions are offered, but available information on the efficiency of these against direct water exposure is insufficient. For structural timber building elements, such as glued laminated timber (GLT), the surface coating should be applied taking into account technological, visual or colour changes (ISO 7724:1984) and – last, but not least – economic aspects are considered. Wood surfaces coated with coating materials, such as varnishes, paints, etc. can stabilize some properties such as movement of moisture content, dimensional changes and attack by microorganisms and fungi. The changes in the moisture content of timber may influence such important parameters as mechanical properties and the total life time of the structural timber elements. A study has been conducted with the aim of assessing the efficiency of coating materials used for wood protection against water absorption. In this study, six different commercial coating products used for the treatment of spruce (Picea Abies L. Karst.) and pine (Pinus Sylvestris L.) samples were tested. The efficiency of different coating substances was assessed using two modified test methods according to the standards EN 382-2 (1994) and EN 927-5 (2006), determining the surface water absorption after immersion in water for 24 h and the dynamics of water absorption of the glued laminated timber for 696 h kept in water. As a result of the study, it has been ascertained that organic solvent-based commercial coating products are more efficient against short-term and long-term wood water absorption compared to oil-based coating materials.

Social enterprises have positive effect on sustainable development, and they have become an important instrument for solving social problems (especially in rural areas), as the national and local governments alone cannot solve all such problems. To foster the development of social entrepreneurship, Latvia has introduced several support instruments for social enterprises, which include tax relief, privileged procurement contracts, grants, as well as non-monetary kinds of support. However, social entrepreneurs often point out that support from the national and local governments is insufficient, while the support instruments stipulated in the Social Enterprise Law are not widely used. Therefore, the aim of the research is to analyse national and local government support instruments for social enterprises in Latvia. The research found that the most important financial instrument fostering the development of social entrepreneurship in Latvia is a grant scheme administered by the Ministry of Welfare and the JSC Development Finance Institution Altum, which is available in the range of EUR 5000 to 200 000 for investment and working capital. In the period 2017‒2020, 94 social entrepreneurship projects with a total budget of EUR 6 million were supported, which could be viewed as significant financial support. In contrast, immovable property tax relief, exemption from enterprise income tax (on profits) and relief from this tax for several categories of non-business expenses are considered by social entrepreneurs to be an insignificant kind of support. There is also lack of experience and practice regarding the inclusion of social criteria in public procurement in Latvia.

Social enterprises have positive effect on sustainable development, and they have become an important instrument for solving social problems (especially in rural areas), as the national and local governments alone cannot solve all such problems. To foster the development of social entrepreneurship, Latvia has introduced several support instruments for social enterprises, which include tax relief, privileged procurement contracts, grants, as well as non-monetary kinds of support. However, social entrepreneurs often point out that support from the national and local governments is insufficient, while the support instruments stipulated in the Social Enterprise Law are not widely used. Therefore, the aim of the research is to analyse national and local government support instruments for social enterprises in Latvia. The research found that the most important financial instrument fostering the development of social entrepreneurship in Latvia is a grant scheme administered by the Ministry of Welfare and the JSC Development Finance Institution Altum, which is available in the range of EUR 5000 to 200000 for investment and working capital. In the period 2017-2020, 94 social entrepreneurship projects with a total budget of EUR 6 million were supported, which could be viewed as significant financial support. In contrast, immovable property tax relief, exemption from enterprise income tax (on profits) and relief from this tax for several categories of non-business expenses are considered by social entrepreneurs to be an insignificant kind of support. There is also lack of experience and practice regarding the inclusion of social criteria in public procurement in Latvia.

It is stated that the strategic benchmark for transformational changes in the economy is currently low-carbon production, the achievement of which is possible to provide with the consistent application of an arsenal of strict control measures, in particular, the introduction of state audit of low-carbon production. The effectiveness of the mechanism for ensuring the implementation of the UN Framework Convention on Climate Change has been assessed. The necessity of implementation in the domestic practice of the state audit of low-carbon production by the decoupling approach is proved. The agri-business portfolio has been formed according to the decoupling approach as one of the leaders in greenhouse gas pollution. The author's economic and mathematical models of estimation according to the decoupling approach of the impact of branches of crop and livestock production on environmental pollution are proposed. The dependence of greenhouse gas emissions on the volume of gross output of agricultural production, capital investment and current expenditures on environmental protection has been established. The results of a comparative analysis of the realism of forecasts of changes in greenhouse gas emissions according to the methodology of the National Academy of Sciences of Ukraine and the author's methodology are highlighted. A roadmap for the introduction of a state low-carbon decoupling audit of the state decoupling audit has been proposed as part of the preparation of the second nationally determined contribution to the Paris Agreement. The expediency of supplementing GRI 300 “Environmental Disclosures” with the group of indicators GRI-305.5 “Reduction of GHG emissions”, formed by the decoupling approach, is substantiated.

It is stated that the strategic benchmark for transformational changes in the economy is currently low-carbon production, the achievement of which is possible to provide with the consistent application of an arsenal of strict control measures, in particular, the introduction of state audit of low-carbon production. The effectiveness of the mechanism for ensuring the implementation of the UN Framework Convention on Climate Change has been assessed. The necessity of implementation in the domestic practice of the state audit of low-carbon production by the decoupling approach is proved. The agri-business portfolio has been formed according to the decoupling approach as one of the leaders in greenhouse gas pollution. The author's economic and mathematical models of estimation according to the decoupling approach of the impact of branches of crop and livestock production on environmental pollution are proposed. The dependence of greenhouse gas emissions on the volume of gross output of agricultural production, capital investment and current expenditures on environmental protection has been established. The results of a comparative analysis of the realism of forecasts of changes in greenhouse gas emissions according to the methodology of the National Academy of Sciences of Ukraine and the author's methodology are highlighted. A roadmap for the introduction of a state low-carbon decoupling audit of the state decoupling audit has been proposed as part of the preparation of the second nationally determined contribution to the Paris Agreement. The expediency of supplementing GRI 300 “Environmental Disclosures” with the group of indicators GRI-305.5 “Reduction of GHG emissions”, formed by the decoupling approach, is substantiated.

The development of organic farming is determined by many factors. On the one hand, it is an increase in demand for food produced in this production system, on the other it is a subsidy system for organic farming under the CAP. The purpose of the article is a comparative analysis of the direction of changes in the development of organic farming in Poland and Latvia compared to the EU in the years 2000–2017. Information was analysed on the organic farming i.e. the area of organic crops, the number of certified farms and organic retail sales, based on FIBL data from the years 2000–2017. An analysis of the trend of changes in organic farming in Poland and Latvia indicates that the development of organic farming in both countries has clearly accelerated after their accession to the EU and after covering organic farming by the CAP support system. However, the case of Poland is definitely different from the trend of changes in organic farming in Latvia and in the EU, where both the number of organic farms and their area increased, with the simultaneous development of the organic food market. There are many indications that mistakes were made in the organic farming subsidy system.

The development of organic farming is determined by many factors. On the one hand, it is an increase in demand for food produced in this production system, on the other it is a subsidy system for organic farming under the CAP. The purpose of the article is a comparative analysis of the direction of changes in the development of organic farming in Poland and Latvia compared to the EU in the years 2000-2017. Information was analysed on the organic farming i.e. the area of organic crops, the number of certified farms and organic retail sales, based on FIBL data from the years 2000–2017. An analysis of the trend of changes in organic farming in Poland and Latvia indicates that the development of organic farming in both countries has clearly accelerated after their accession to the EU and after covering organic farming by the CAP support system. However, the case of Poland is definitely different from the trend of changes in organic farming in Latvia and in the EU, where both the number of organic farms and their area increased, with the simultaneous development of the organic food market. There are many indications that mistakes were made in the organic farming subsidy system.

This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

The work presents foundations of the dynamics of the flat-parallel movement of a bridge agricultural unit in a horizontal with the kinematic method of its control (turning the wheels) by changing the position of one of its parts relative to the other. The analysis of assessment of the degree of impact of the scheme and parameters of the investigated agricultural tool upon its controllability and stability of movement is based on the amplitude and phase frequency characteristics. The mathematical models of the movement of the bridge agricultural unit are presented in a differential and an operator form of recording. Based on mathematical models, the calculated amplitude and phase frequency characteristics of the dynamic control system of the control impact, presented as the angular displacement of its half-frames ψ, are constructed for various parameters and operating modes. The constructed mathematical models, amplitude and phase frequency characteristics make it possible to assess the impact of the control parameter of the bridge agricultural unit, as well as its design and other parameters upon the controllability of the movement.

The work presents foundations of the dynamics of the flat-parallel movement of a bridge agricultural unit in a horizontal with the kinematic method of its control (turning the wheels) by changing the position of one of its parts relative to the other. The analysis of assessment of the degree of impact of the scheme and parameters of the investigated agricultural tool upon its controllability and stability of movement is based on the amplitude and phase frequency characteristics. The mathematical models of the movement of the bridge agricultural unit are presented in a differential and an operator form of recording. Based on mathematical models, the calculated amplitude and phase frequency characteristics of the dynamic control system of the control impact, presented as the angular displacement of its half-frames ψ, are constructed for various parameters and operating modes. The constructed mathematical models, amplitude and phase frequency characteristics make it possible to assess the impact of the control parameter of the bridge agricultural unit, as well as its design and other parameters upon the controllability of the movement.