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Because of the electric propulsion, electric scooters could be a potential way how to decrease greenhouse gas (GHG) emissions in urban transportation sector; however, recent research has cast doubt on that. This article focuses on the effect the electric scooter use has on CO2 emissions by examining the electric scooter trip data obtained during 2021 scooter season in Riga city. As shared scooters routinely replace already existing modes of transportation, the article analyses the effect which this replacement has on net CO2 emissions in the city. We argue that not all replacement modes will bring actual decrease of CO2 emissions. The results indicate that most of the shared e-scooter trips in Riga fall into the 1-2 km distance category, where it replaces not just cars, but also public transportation, walking and cycling, and actually increases CO2 emissions. The article examines the factors contributing to the CO2 emissions and relative impact of each. The results demonstrate that the largest impact comes from the scooter and battery manufacturing, thus scooter lifetime has decisive impact on the overall net CO2 emissions. In addition, this research found fundamental differences between expected scooter lifetime data claimed by shared scooter operators (5 years) and the average reallife data (156 days). It results in shared e-scooters creating additional 239.9 tonnes CO2 in Riga, and minimum scooter lifetime should be at least 5 years, for shared scooters to become CO2 neutral. This study aims to contribute to transportation literature by demonstrating net CO2 emission calculation methodology as well as empirical evidence on e-scooter trips in North-Eastern Europe region and to help local authorities to make decisions on reaching environmental targets in transportation sector.

This paper studies the effects of a reduction in the countercyclical capital buffer requirements on interest rate growth in Norway. For the first time since the implementation of Basel III framework the new macroprudential tools were put to a test by an exogenous shock in the form of the pandemic. Using bank-level data we disentangle the effects of such a cut on interest rate growth in four different sectors. We find that banks following the policy shock significantly reduced their interest rates and exhibited negative interest rate growth. On average capital constrained banks had a relatively smaller negative interest rate growth than better capitalized banks. The robust evidence suggests an effect of 0.54 percent smaller negative mortgage interest rate growth and 0.91 percent smaller negative corporate interest rate growth. Above mean capitalized banks exhibit a more sensitive response to countercyclical capital buffer cut. The results are highly significant but opposite of what previous literature finds.

The European Copernicus programme ensures long-term delivery of high-quality, global satellite ocean colour radiometry (OCR) observations from its Sentinel-3 (S3) satellite series carrying the ocean and land colour instrument (OLCI). In particular, the S3/OLCI provides marine water leaving reflectance and derived products to the Copernicus marine environment monitoring service, CMEMS, for which data quality is of paramount importance. This is why OCR system vicarious calibration (OC-SVC), which allows uncertainties of these products to stay within required specifications, is crucial. The European organisation for the exploitation of meteorological satellites (EUMETSAT) operates the S3/OLCI marine ground segment, and envisions having an SVC infrastructure deployed and operated for the long-term. This paper describes a design for such an SVC infrastructure, named radiometry for ocean colour satellites calibration and community engagement (ROSACE), which has been submitted to Copernicus by a consortium made of three European research institutions, a National Metrology Institute, and two small- to medium-sized enterprises (SMEs). ROSACE proposes a 2-site infrastructure deployed in the Eastern and Western Mediterranean Seas, capable of delivering up to about 80 high quality matchups per year for OC-SVC of the S3/OLCI missions.

International audience; The European Copernicus programme ensures long-term delivery of high-quality, global satellite ocean colour radiometry (OCR) observations from its Sentinel-3 (S3) satellite series carrying the ocean and land colour instrument (OLCI). In particular, the S3/OLCI provides marine water leaving reflectance and derived products to the Copernicus marine environment monitoring service, CMEMS, for which data quality is of paramount importance. This is why OCR system vicarious calibration (OC-SVC), which allows uncertainties of these products to stay within required specifications, is crucial. The European organisation for the exploitation of meteorological satellites (EUMETSAT) operates the S3/OLCI marine ground segment, and envisions having an SVC infrastructure deployed and operated for the long-term. This paper describes a design for such an SVC infrastructure, named radiometry for ocean colour satellites calibration and community engagement (ROSACE), which has been submitted to Copernicus by a consortium made of three European research institutions, a National Metrology Institute, and two small-to medium-sized enterprises (SMEs). ROSACE proposes a 2-site infrastructure deployed in the Eastern and Western Mediterranean Seas, capable of delivering up to about 80 high quality matchups per year for OC-SVC of the S3/OLCI missions.

Visual poetry in Latvian literature is still an extraordinary phenomenon. In this case, by extraordinary is meant its scarce appearance among the corpus of Latvian literary texts – only very few examples of it exist in Latvian literature even in the 21st century, though it has gained a visible presence in other literatures of the world since at least the era of Modernist poetry, and experienced in most cases a turn of critical attitude towards it from disregard or denial to acceptance and consideration. At first evaluated only as a pastime on the margins of serious literature, since Apollinaire it has evolved into a serious genre of poetry and art of its own, and is no longer considered a childish game. Given this situation in contemporary criticism, it is quite a peculiar situation that Latvian literature and literary criticism still does not pay adequate attention to it, thus visual poetry has stayed an outsider genre up to this day. In this paper a concise historical account of Latvian visual poetry will be given and some examples of visual poetry from various decades of Latvian literature will be given, as well as quotations from Latvian literary critics and scholars regarding visual poetry will be provided, in order to illustrate the overall situation in Latvian visual poetry and the possible reasons why it is still being mostly neglected and disregarded both by poets/artists and critics, though there seems to be slight indications of a visual turn.

The paper considers a survey of the research procedures and results due to invariant control method application perspective for operation quality advancement in several technological plants (wastewater biological treatment tanks and water steam production boilers), which operate under influence of organised and random disturbances. A specified subject of research is the simulation model of the multi-link invariant control system for steam pressure stabilisation in a steam boiler by preemptive compensation of steam load and feed water flow impact on output parameter (steam pressure), developed in MATLAB/SIMULINK. Simulation block-diagram of the steam boiler invariant control system, containing closed loop PID control circuit and open loop DPC circuit, has been composed on the basis of the designed mathematical model of the system components, disturbance compensation algorithms, and operational equation of the invariant control system. Comparative response of the steam boiler, operating under influence of fluctuating disturbances, with conventional PID control and using PID-DPC control with disturbance compensation controller DPC, has been investigated. Simulation results of invariant PID – DPC control system show that output parameter of the steam boiler - pressure remains practically constant under fluctuating disturbances due to a high-speed response of DPC controller.

The main aim of the current paper is to create a mathematical model for dual layer shell type recuperation system, which allows reducing the heat losses from the biomass digester and water amount in the biogas without any additional mechanical or chemical components. The idea of this system is to reduce the temperature of the outflowing gas by creating two-layered counter-flow heat exchanger around the walls of biogas digester, thus increasing a thermal resistance and the gas temperature, resulting in a condensation on a colder surface. Complex mathematical model, including surface condensation, is developed for this type of biogas dehumidifier and the parameter study is carried out for a wide range of parameters. The model is reduced to 1D case to make numerical calculations faster. It is shown that latent heat of condensation is very important for the total heat balance and the condensation rate is highly dependent on insulation between layers and outside temperature. Modelling results allow finding optimal geometrical parameters for the known gas flow and predicting the condensation rate for different system setups and seasons.

Purpose. The paper is aimed to present the new approach to the promotion of university students’ entrepreneurship which was elaborated and researched in the Faculty of Engineering Economics and Management of Riga Technical University within the study course „Economics of Entrepreneurship”. Methodology. It is argued that opportunity identification (Baron, 2006), opportunity creation (Sarasvathy, et al., 2003) and opportunity development (Virtanen, 2010) are the prerequisites for the creation of new economic values which makes the heart of entrepreneurship (Drucker, 1993). In order to make the study process more entrepreneurship enhancing, it is necessary to avoid traditional teaching and learning methods such as lectures, literature reviews and examinations (Gibb, 2002). Instead, the working out of opportunity-centered (Rae, 2003) and problem-based (Tan & Frank, 2006) study models, maximally “pushing” students into entrepreneurship through the structuring of learning like an entrepreneurial process (Hjorth & Johannisson, 2007) should become the key elements of contemporary advanced education for entrepreneurship. Therefore the “Opportunity-oriented 7-step-problem-based learning model for developing students’ entrepreneurship” (Oganisjana, 2015) was elaborated and tried out in secondary schools of Latvia and Malaysia within ASEM (Asia-Europe Lifelong Learning Research HUB) from 2011 to 2014. The analysis of the results of the research served as a basis for adapting this model for university students with its further application in practice within the framework of the National Research Program EKOSOC-LV in the autumn semester of 2014. It was qualitative research for discovering the aspects of the new approach to the teaching and learning process and getting students’ feedback in the beginning and in the end of the course. Students filled in Google Drive electronic forms and sent them to the authors. The questions of the reflections concerned what students liked and disliked in the course, what and who helped or disturbed them while working in teams, what and who surprised them, what they considered in the course to be especially important to them and what they would recommend to change, etc. The qualitative content analysis of the texts of the reflections provided the discovery of the factors which promote and hinder the opportunity–oriented problem-based teaching and learning for entrepreneurship in the university. Results. Students evaluated the course very positively, mentioning: 1) the given opportunity to solve real life problems and work with entrepreneurs; 2) development of their creativity, presentation, analytical and social skills, 3) the democratic atmosphere and teachers’ enthusiasm, professionalism and positive attitude towards them. However there was certain criticism related to overload with work, not clear instructions in some cases and the time of the lectures which took place very early in the morning. The theoretical contribution. The paper presents an entrepreneurship promoting study model, which links and unites two stages of lifelong learning: secondary school and university, thus making a universal theoretical basis for solving this topical educational problem. Practical implications “Opportunity-oriented 7-step-problem-based learning model for developing students’ entrepreneurship” can be an appropriate basis for organising studies not only in secondary schools and universities, but as well in adult and kindergarten education. Keywords: development of entrepreneurship, opportunity-oriented learning, problem-based learning. Paper type : Research paper.

ESTCube-1 is a student satellite project lead by the University of Tartu, Estonia, and supported by the European Space Agency (ESA) via Plan for European Cooperating States (PECS). Development of ESTCube-1 has been a collaborative effort with many international partners. The satellite is shown on Figure 1 [1].

The paper presents first stage of research for numerical modelling of heat exchange in counterflow shell-type system with variable dimensions, which is partly placed under the ground level. Mathematical model of heat and mass balance is reduced to 1D case to make numerical calculation faster. Different kinds of boundary conditions (surface temperature, convection) and various physical properties of layer between pipes (from non-insulated to well insulated) are used to check the usability of created model.

The scientific mission of ESTCube-1, launched in May 2013, is to measure the electric solar wind sail (E-sail) force in orbit. The experiment is planned to push forward the development of the E-sail, a propulsion method recently invented at the Finnish Meteorological Institute. The E-sail is based on extracting momentum from the solar wind plasma flow by using long thin electrically charged tethers. ESTCube-1 is equipped with one such tether, together with hardware capable of deploying and charging it. At the orbital altitude of ESTCube-1 (660–680 km) there is no solar wind present. Instead, ESTCube-1 shall observe the interaction between the charged tether and the ionospheric plasma. The ESTCube-1 payload uses a 10-m, partly two-filament E-sail tether and a motorized reel on which it is stored. The tether shall be deployed from a spinning satellite with the help of centrifugal force. An additional mass is added at the tip of the tether to assist with the deployment. During the E-sail experiment the tether shall be charged to 500 V potential. Both positive and negative voltages shall be experimented with. The voltage is provided by a dedicated high-voltage source and delivered to the tether through a slip ring contact. When the negative voltage is applied to the tether, the satellite body is expected to attract the electron flow capable of compensating for the ion flow, which runs to the tether from the surrounding plasma. With the positive voltage applied, onboard cold cathode electron guns are used to remove excess electrons to maintain the positive voltage of the tether. In this paper we present the design and structure of the tether payload of ESTCube-1.

This paper presents the mission analysis, requirements, system design, system level test results, as well as mass andpower budgets of a 1-unit CubeSat ESTCube-1 built to perform the first in-orbit demonstration of electric solar wind sail (E-sail)technology. The E-sail is a propellantless propulsion system concept that uses thin charged electrostatic tethers for turning themomentum flux of a natural plasma stream, such as the solar wind, into spacecraft propulsion. ESTCube-1 will deploy and chargea 10 m long tether and measure changes in the satellite spin rate. These changes result from the Coulomb drag interaction with theionospheric plasma that is moving with respect to the satellite due to the orbital motion of the satellite. The following subsystemshavebeendevelopedtoperformandtosupporttheE-sailexperiment: atetherdeploymentsubsystembasedonapiezoelectricmotor;an attitude determination and control subsystem to provide the centrifugal force for tether deployment, which uses electromagneticcoils to spin up the satellite to one revolution per second with controlled spin axis alignment; an imaging subsystem to verify tetherdeployment, which is based on a 640 × 480 pixel resolution digital image sensor; an electron gun to keep the tether at a highpositive potential; a high voltage source to charge the tether; a command and data handling subsystem; and an electrical powersubsystem with high levels of redundancy and fault tolerance to mitigate the risk of mission failure.