Reed canary grass cultivation’s energy efficiency and fuel quality

ArticleThe article discusses the energy yield and yield capacity of reed canary grass stands in semi-natural and cultivated meadows with edaphic conditions most favourable for species growing on fertile soil. Energy grass production yields have been assessed with respect to the issues of precipitation, sunshine, and frozen ground. In Estonia, a dried matter level of 4.2– 8.5 t ha-1 of reed canary grass may produce 72.91–147.56 GJ ha-1 gross energy by using 1.48– 3.06 GJ ha-1 input energy, which consequently nets 71.44–1,445.00 GJ ha-1 . The above finding indicates that 1 MJ input energy enables the production of 2.8 kg dry matter. The efficiency of energy production (ratio of energy returned on energy invested) depends on the amount of input energy used to grow and harvest reed canary grass. The input energy payback ratio for the given case was 48.2–49.4, which was higher than cases with lower and higher dry matter yield levels. Precipitation during the second part of the Estonian summer, heavy winter snow cover and a simultaneous frequent lack of frozen ground reduce the productivity of reed canary grass as energy hay because the winter or early spring harvest cannot be used

Contribution of pumped hydro energy storage for more RES utilization on autonomous power systems

ArticleThis paper addresses the performance issues of autonomous power systems under high renewable energy sources (RES) penetration. Renewable energy sources could be the main option for isolated power generation at remote locations in case that energy storage introduced. At the moment, pumped hydro storage (PHS) units and batteries storage systems (BSS) represent the most mature technologies for large scale energy storage. The basic criteria for this kind of energy storage unit installations include, (a) the existence of an autonomous power system with local power stations, (b) the high electricity production cost, (c) the potential of renewable energy sources (mainly wind and solar), and (d) the non-flat terrain morphology (for PHS). Greek islands represent ideal cases for large scale energy storage installations, as they fulfil all the above criteria. This paper shows the effect of the installation of a planned PHS unit in Crete island. The calculations are based on real data provided by the Cretan power system operator, whereas the results show the effect of energy storage units operation on the energy mix, as well as the economic viability of the project, which is combined with significant environmental benefits

Roosi talu sauna projekteerimine ja ehitustööd : loov-praktiline lõputöö

https://www.ester.ee/record=b5239672*es

Applying Peer-to-peer Technology In Virtual Worlds

Klassikaliste klient-server arhitektuuril põhinevate virtuaalmaailmade üheks nõrgaks kohaks on serverid, milledesse virtuaalmaailma kliendid ühenduvad. Kui tegemist on suure kasutajaskonna ja suure kasutatavusega virtuaalmaailmaga, siis kipuvad serverite halduskulud kasvama väga kiiresti ning nende kesise haldamise korral võivad kasutajad kogeda ebameeldivusi antud teenuse tõrkumise tõttu. Lisaks sellele on ka kontroll antud keskkonna üle serverite haldajatel, mistõttu võivad viimased ette teatamata oma teenused sulgeda. Klient-server arhitektuuril põhinevad populaarsetest teenustest nii World of Warcraft kui ka Second Life. Peer-to-peer (P2P) arhitektuur erineb klient-server arhitektuurist selle poolest, et iga osaleja P2P-l põhinevas võrgus võib käituda nii kliendi kui ka serverina – puudub keskne ühenduspunkt. Peer-to-peer tehnoloogial põhinevad näiteks populaarne failivahetuskesk-kond BitTorrent1 ja suhtluskeskkond Skype2. Tuhandete kasutajatega ja rikkaliku sisuga virtuaalmaailmad võivad vajada võrdlemisi palju ressursse, sh. arvutusvõimsust, internetiühenduse ribalaiust ja andmete salvestus-mahtu. Klient-server mudeli puhul on pudelikaelaks serverid, milledesse kliendid ühendu-vad – serverid peavad olema piisavalt võimsad ning neid peab olema piisavalt palju, et kliente samaaegselt hallata ja virtuaalmaailma simulatsiooni töös hoida. Peer-to-peer mudel kõrvaldab selle pudelikaela, võimaldades ühel kliendil jagada ülesandeid laiali teistele, vähem koormatud klientidele. Näiteks, kui kasutajad kirjutavad skripte, mis vajavad arvestatava hulga arvutusvõimsust (animeerides mingit objekti või lahendades mõnda arvutusülesannet), siis klient-server mudeli puhul on serveri ülesandeks klientide skripte jooksutada ning suur klientide ja skriptide arv võib serveri üle koormata. Seevastu P2P arhitektuuri puhul on võimalik rakendada koormusjaotusalgoritme ning leida kliendid, kellele võiks delegeerida mõnede skriptide jooksutamise selle alusel, kui palju ressursse ja arvutusvõimsust neil parasjagu üle on. Selline peer-to-peer tehnoloogial põhinev koormuse jaotamine võimaldab pakkuda kee-rulisemat ja rikkalikumat virtuaalmaailma kogemust klientidele. Koormuse jaotamine võimaldab vähendada teenusepakkuja kulusid interneti teenusele ja energiale. Siiski võib P2P võrgu osaliste koondkulu olla suuremgi kui tavalise klient-server võrgu puhul, kuna kõik osalised võivad olla võrdselt hõivatud, andes oma panuse ressursside kasutamisse. Samal ajal lisab P2P kasutamine ka turvariske, võrreldes klient-server mudeliga, milles on sisuliselt ainult üks usaldust vajav komponent – server. Käesoleva töö eesmärgiks on võrrelda klient-server mudeli ja peer-to-peer mudeli efektiivsust ja P2P arhitektuuri rakendatavust virtuaalmaailmades. Selleks viisime läbi katsed teadusuuringute tarbeks ehitatud virtuaalmaailmaga VirtualLife.The purpose of the given thesis is to investigate the usability and effectiveness of peer-to-peer architecture in contrast to traditional client-server architeture when simulating virtual worlds. In addition, we study how peer-to-peer helps to reduce the cost of ownership for the service provider as opposed to the traditional client-server architecture. A number of experiments were conducted with scientific research project VirtualLife using both peer-to-peer and client-server architectures. The experiments were conducted on a special-purpose cluster computer consisting of multiple virtual nodes. Some experiments were also repeated on a non virtualized environment consisting of physical computers, since it was found that the virtualized environment might have had a negative effect on the performance of the simulation. Based on the experiment results we conclude that using peer-to-peer architecture when simulating virtual worlds helps to provide a better user experience while reducing the cost of ownership for the service provider. We also confirm that the usage of peer-to-peer architecture might increase the bandwidth load and resource usage for the client participating in the virtual world

Stalinismi „Teised“: Ilmi Kolla kui teisitimõtleja / Stalinism’s ”Others”: Ilmi Kolla as a dissenter

Artikkel käsitleb luuletaja Ilmi Kolla (1933–1954) luulet stalinismiperioodi kontekstis kui vastupanu ajastu diskursiivsetele jõujoontele. Ilmi Kolla luuletuste enamikku ei olnud võimalik avaldada, sest need ei vastanud sotsialistliku realismi ja stalinliku ideoloogia nõuetele. Ka avaldamiseks vastu võetud tekstide puhul heitsid ajalehtede ja ajakirjade toimetused talle sageli ette luuletuste sobimatust kehtivate ideoloogiliste ja esteetiliste nõuetega. Selles mõttes võib Ilmi Kolla luulet näha sotsiaalse protestina, mis ei olnud küll otseselt selle eesmärgiga loodud, kuid mis toimis sellisel moel. The article analyzes the poetry of the Estonian writer Ilmi Kolla as the resistance toward the discursive hegemony of the Stalinist era. The dominant tenor of the Stalinist era was falsely optimistic, leaving no space for articulations of individual experiences and existential questions, the topics which were central for Ilmi Kolla’ poetry. The writers could not, in the Stalinist era, publicly oppose the ideological and social demands of Soviet rule. Instead, one could adapt the position of a passive dissenter; in the context of literary production, such a position could mean remaining silent (i.e. not publishing texts) or cultivating aesthetic practices which were out of touch with the official ideological demands of the era – this last option meant writing into the drawer.During the Stalinist period in Estonian SSR, the only officially accepted method of creating literary texts was ‘socialist realism.’ The acceptance of this method suggested ideological conformism; indeed many authors conformed to the ideological demands of the era. Estonian literature of earlier periods was re-evaluated according to Stalinist ideological demands. In poetry, the newly-established demand for socialist realism prescribed the range of accepted topics; acceptable themes included war, building up the new socialist society, class struggle and the struggle for peace, and the worship of Stalin. Ideological emphasis was laid on the foregrounding of a collective viewpoint and communist values. However, there were several authors who did not conform to the pressure; the poetess Betti Alver, for example, did not publish any poems during the twenty postwar years.Ideological education of authors became one of the cornerstones of producing the socialist realist works; of particular importance was guiding the literal production of young authors. This was arranged through the Writers Union, where advisers of prose and poetry were employed. Journal editors performed the same role and critical articles were published concerning the production of young authors. As a young author, the position of Ilmi Kolla in the Soviet literary landscape was precarious because she hardly complied with requirements of socialist realism. Therefore, she failed to publish most of her poems. Kolla indeed tried to conform and wrote conforming poetry for earning income, but these poems often failed. Even poems which were accepted by the editorial board for publication were not considered ideological enough and were harshly criticized. The central theme in Kolla’s poetry was individual and erotic love, instead of collective values demanded by socialist realism. Kolla’s poetry tended to have existential undertones and was tempered by a sense of sorrow. Such poetic modes were considered unacceptable in the context of Stalinism since these indicated a sense of human weakness, understood according to Stalinist ideology as lacking in optimism and yielding to negativity and decadent feelings. The most well known poem by Kolla, “Sorrowful moments” carries a sense of an approaching death; it focuses on an individual who loves and longs for the happiness, whose soul is sick and who is thinking about the transciense of life and about the appoaching death. This poem was published only after Kolla’s death in 1957 and then became widely read. The poem has been considered Kolla’s existential outcry; it has been interpreted as a turning point in the poetic practices of the period (Veidemann 2000). Many poems by Ilmi Kolla which she could not publish during her lifetime were distributed from hand to hand in a manuscript form after her death, impacting in this way the attitudes of many people. Readers have recalled how discovering the poetry of Kolla affected them strongly in the Stalinist atmosphere of the 1950s; many remember how Kolla’s poems became close to their hearts and were experienced in the context of the era as something extraordinary and out of sync with the official trends. A collection of Kolla’s poetry was published after her death in 1957, but the compiler Heljo Mänd has acknowledged that she did not dare to publish Kolla’s more spiritual poetry because of the fear of criticism. Since individualism was suppressed in the Soviet Union, the expression of poetic individualism can be understood as a form of dissent or opposition  (Hersch 2016). Therefore, the poetry of Ilmi Kolla can be seen as an opposition to Soviet rule and as a protest toward society which repressed individuality. In addition to Kolla’s poetry as a poetic dissent, her freeminded personality was also somewhat inappropriate in the Soviet system. As many other writers, Kolla teased the system, conformed where necessary, but also used the system in her own interests. The poetry of Ilmi Kolla can be understood as a social protest which was not directly created for the purpose of dissent, but which functioned in this way in the Stalinist and post-Stalinist society

Honoraripoliitikast Eestis stalinismi perioodil. The Politics of Royalties in Estonia During the Stalinist Era

The article treats the topic of royalty politics within the field of Estonian literature during the Stalinist era. This is an introductory treatment of the topic with the aim of opening up a discussion and to introduce corresponding sources. The topic of royalties has avoided the attention of researchers; up until now, no studies have been made. Despite this, it is an important topic, since the role of royalties in Soviet cultural politics shouldn’t be underestimated. Even though the cultural politics of the Soviet system are usually treated as repressive pressure, the politics of royalties bring out a different aspect by revealing a bonus system with which authors were incited to create conformist texts. Several different kinds of sources relating to royalties can be found , the most important of them being the laws on author royalties. The first of these was the Author Royalties Act passed by the People’s Commissariat of the Estonian SSR and in force already in 1944. Laws passed in 1948 and 1952 regulated the payment of royalities for both fictional works as well as all other kinds of works, such as scientific and technical publications, popular science, dictionaries, school text books, various kinds of collections, translations, etc. The laws were passed according to the boundaries of the work, such as artistic value or ideological level. Larger royalties were paid for works which were ’better’ in an ideological sense. Fiction and literary studies paid the best, which shows just how important literature as ideological education was to the Soviet system. The laws were in-depth and detailed and saw regular additions, such as in 1960 when several regulations were issued. Archival sources and honorary copies of Estonian newspapers and authorpublisher agreements consitute other important sources in addition to the legislation. From the honorary copies , the size of the royalties paid becomes clear. The source value of these documents is confirmed by the fact that they were used as bookkeeping material by editorial offices. The publisher agreements also provide an idea of the actual royalties. In the article, poetess Betti Alver’s publisher agreements from the end of 1940 are used as an example. A concrete example of the politics of royalties used in the article is what happened with poetess Ilmi Kolla (1933–1954). Kolla’s correspondence and several manuscript notes open up a view of the background to her creative work, and show the role of royalties in an age of ideological demands and the effort to create suitable poems. In the 1940s and 1950s, royalties were relatively large in comparison with the standard of living, constituting Ilmi Kolla’s main source of income and contributing to creative conformism. The Soviet system’s royalty politics can indeed be seen as a kind of hidden bonus which stimulated authors to write conformist texts, revealing the relationship between ideology and material aspects

Retraction: Determination of efficiency in the design phase of the enterprise by the method of finite relations

Saabunud / Received 03.10.2019 ; Aktsepteeritud / Accepted 15.11.2019 ; Avaldatud veebis / Published online 29.11.2019 ; Vastutav autor / Corresponding author: Andres Annuk e-mail: [email protected] manuscript "DETERMINATION OF EFFICIENCY IN THE DESIGN PHASE OF THE ENTERPRISE BY THE METHOD OF FINITE RELATIONS" by Valerij Karpov, Artem Nemtsev, Toivo Kabanen and Andres Annuk was submitted to Agraarteadus on 3 November 2019, accepted on 15 November 2019 and published on In Press on 29 November 2019. In December 2021, we received expressions of concern from the Academic Ethics Commission of the Estonian University of Life Sciences about similarities with the article entitled "Determination of efficiency in the design phase of the enterprise by the method of finite relations" ("Opredelenie jenergeticheskoj jeffektivnosti na jetape proektirovanija predprijatija metodom konechnyh otnoshenij") [In Russian] https://cyberleninka.ru/article/n/opredelenieenergeticheskoy-effektivnosti-na-etape-proektirovaniya-predpriyatiyametodom-konechnyh-otnosheniy/pdf by Valerij Karpov and Artem Nemtsev submitted to Bulletin of MSTU, vol. 18, no. 4, 2015, pp. 709– 718 (Vestnik MGTU, tom 18, # 4, 2015 g. str. 709–718). The expert of the Academic Ethics Commission of the Estonian University of Life Sciences analysed articles for similarities. The analysis revealed that the two articles reported the same experiments and the same results. Small divergences existed in the list of authors, in the Introduction, and the References. These divergences, however, are minor and were explained by the corresponding author. The corresponding author admitted that he was not aware of a previously published article. As a result, the article in Agraarteadus, accepted at a later date, is considered a duplicate publication. On this basis, we have decided to retract the article

Haiguse kujutamine luuletaja Ilmi Kolla kirjades

Private letters are the least researched genre of autobiographical writings. Irrespective of this fact, letters can indeed offer abundant research material about the ailing person’s perceptions of the disease and how he/she depicts this in writing. The article dwellsupon the depiction of disease, based on the letters by Ilmi Kolla (1933–1954), using the concept of (auto)pathography as an analytical means. The focus is on how the illness is being textualised in letters and how the epistolary genre affects such a depiction.Ilmi Kolla’s letters reflect the progress of her disease, presenting this from the author’s viewpoint, yet adapting it according the addressees – e.g., Ilmi Kolla’s letters to her mother are written in a more optimistic tone regarding her illness than the ones to poet Debora Vaarandi expressing greater concern. The letters reveal various facets of the disease and her state of mind with regard to the illness, presenting a picture of sanatorium and hospital treatment. In line with the growing severity of Ilmi Kolla’sdisease, the illness becomes gradually more visible in her letters, encompassing increasing textual space. Thus, the ailment has become one of the main topics in I. Kolla’s letters sent from the hospital during the last six months of her life.The fact that letters tend to be fragmentary texts separated from each other by a temporal-spatial distance becomes evident in the narrative of disease constructed by the letters. Although such an illness narrative lacks coherence intrinsic of a traditionallinear autobiographic text, such a life history or a diary, an epistolary story of an illness can be studied from the viewpoint of auto-pathography as the letters create an autobiographic description of the illness.As unpublished texts, letters can both reflect and oppose the discourses of the time. The depiction of the disease, and that of an ailing body, revealed in Ilmi Kolla’s letters, functions as a counter-discourse to the body image of the Stalinist era, which highlighteda healthy, strong and powerful female body. As such, the reflection of the disease in the letters actually brings out the cultural and gender-wise meanings related to the disease, highlighting the illness as a cultural construct

Evaluation of the Accuracy of Different PV Estimation Models and the Effect of Dust Cleaning: Case Study a 103 MW PV Plant in Jordan

The estimation of PV production has been widely investigated previously, where many empirical models have been proposed to account for wind and soiling effects for specific locations. However, the performance of these models varies among the investigated sites. Hence, it is vital to assess and evaluate the performance of these models and benchmark them against the common PV estimation model that accounts only for the ambient temperature. Therefore, this study aims to evaluate the accuracy and performance of four empirical wind models considering the soiling effect, and compare them to the standard model for a 103 MW PV plant in Jordan. Moreover, the study investigates the effect of cleaning frequency on the annual energy production and the plant’s levelized cost of electricity (LCOE). The results indicate almost identical performance for the adopted models when comparing the actual energy production with R2 and RMSE (root mean square error) ranges of 0.93–0.98 and 0.93–1.56 MWh for both sub-plants, with a slight superiority of the models that incorporate wind effect. Finally, it is recommended in this study to clean the PV panels every two weeks instead of every three months, which would increase annual energy production by 4%, and decrease the LCOE by 5% of the two PV sub-plants