Opin vísindi
Opin vísindi er varðveislusafn vísindaefnis og doktorsritgerða í opnum aðgangi á vegum íslenskra háskóla og Landsbókasafns Íslands - Háskólabókasafns.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Opinn aðgangur að rannsóknaniðurstöðum er í samræmi við 10. gr. laga nr. 3/2003 um opinberan stuðning við vísindarannsóknir sem og kröfur innlendra og erlendra rannsóknasjóða. Markmiðið með opnum aðgangi er að niðurstöður rannsókna séu aðgengilegar sem flestum óhindrað og án endurgjalds á rafrænu formi. Vistun í varðveislusafninu er varanleg og ætlað að tryggja aðgang að vísindaefni íslenskra háskóla í opnum aðgangi um ókomna tíð. Varðveislusafnið Opin vísindi er tengt við rannsóknagáttina IRIS og rannsóknaniðurstöður í opnum aðgangi sem eru skráðar í IRIS eru um leið vistaðar og gerðar aðgengilegar til framtíðar í varðveislusafninu. Með því að safna þessu efni saman í eitt safn verður aðgangur að því einfaldur og þægilegur fyrir alla sem vilja kynna sér það og geta þannig notið þess öfluga vísindastarfs sem fram fer í háskólum landsins.
Varðveislusafnið er OpenAIRE / OpenAIREplus samhæft og samrýmist kröfum sem gerðar eru um birtingu rannsóknaniðurstaðna úr verkefnum sem styrkt eru úr evrópsku rannsóknaáætlununum FP7 og H2020.
Varðveislusafnið notar opna hugbúnaðinn DSpace.
Nýlega bætt við
The effects of travel on performance : a 13-year analysis of the National Rugby League (NRL) competition
(2022) Read, Dale B.; Williams, Sean; Fullagar, Hugh H.K.; Weakley, Jonathon J.S.; Department of Sport Science
The purpose was to investigate the effects of travel on performance in the National Rugby League (NRL). A total of 4,704 observations from 2,352 NRL matches (2007–2019) were analysed. The effect of travel on match outcome (i.e., win/loss) was analysed using a generalized linear mixed model, and the points difference using a linear mixed model. For every 1,000 km travelled in the NRL, the estimated probability of winning a match was reduced by −2.7% [−5.7 to 0.3%] and the estimated points difference by −1.1 [−2.0 to −0.2] points. In relation to every 1,000 km travelled, the 2007–2009 seasons had the greatest reduction in the likelihood of winning a match (−2.7% [−4.7 to −0.6%]), with the 2018–2019 seasons having the greatest likelihood (1.1% [−1.2 to 3.3%]). Regarding inter-state travel, teams from the state of Queensland had the greatest reduction in the likelihood of winning a match while the team from the state of Victoria had the greatest likelihood, although there were no clear differences between states. These data suggest that travel has impacted performance in NRL matches although this effect has reduced over time. These findings are useful for practitioners that prepare athletes in sports where frequent short-haul travel is required.
Mutual Coupling Reduction in Closely Spaced MIMO Dielectric Resonator Antenna in H-Plane Using Closed Metallic Loop
(2022) Elahi, Manzoor; Altaf, Amir; Almajali, Eqab; Yousaf, Jawad; Department of Engineering
In this study, the mutual coupling in multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is reduced by employing closed metallic loops. The loops are wrapped around the adjacent edges of the dielectric resonators (DR) where magnetic coupling is significant. The proposed method employs only the conductive metallic strips for mutual coupling reduction and this makes the entire design very simple and compact. The impedance bandwidth varies from 4.73 to 5.1 GHz, covering the Sub-6 GHz 5G band. The realized MIMO DRA has an isolation of 28 dB at the resonant frequency with a measured peak gain at each port of 3.5 dBi and a peak radiation efficiency of 93%. The obtained measured results yield a low correlation coefficient (< 0.05) mostly at the entire band that contribute to diversity gain (> 9.8 dB) to increase the capacity of communication system, is reported in this paper. The proposed antenna was fabricated and the closed loop strip is wrapped around using in house facility. Furthermore, some issues related to the fabrications tolerance have been investigated to justify the difference between some simulated and measured results.
A D-Band Waveguide-SIW Transition for 6G Applications
(2022) Altaf, Amir; Elahi, Manzoor; Abbas, Syed Muzahir; Yousaf, Jawad; Almajali, Eqab; Department of Engineering
In this work, a design of a transition from a standard D-band waveguide to substrate integrated waveguide (SIW) technology is presented for 6G applications. The waveguide is connected to an SIW by carving a slot at the bottom metal of the printed circuit board (PCB). A pair of vias is added to shift the inband null to a higher frequency, whereas a parasitic patch is used to improve impedance matching. A prototype of a back-to-back SIW transition is fabricated and measured using D-band VNA extenders. The measurement shows a -10 dB impedance bandwidth of 26.5 GHz (135–161.5 GHz) and a 3-dB bandwidth of 28 GHz (133.8–161.8 GHz). The transition can be integrated with a D-band antenna for 6G applications.
Soft stimulation treatment of geothermal well RV-43 to meet the growing heat demand of Reykjavik
(2021-11) Hofmann, Hannes; Zimmermann, Günter; Huenges, Ernst; Regenspurg, Simona; Aldaz, Santiago; Milkereit, Claus; Heimann, Sebastian; Dahm, Torsten; Zang, Arno; Grigoli, Francesco; Karvounis, Dimitrios; Broccardo, Marco; Wiemer, Stefan; Hjörleifsdóttir, Vala; Kristjánsson, Bjarni Reyr; Hersir, Gylfi Páll; Ásgeirsdóttir, Ragnheiður St; Magnússon, Rögnvaldur; Árnadóttir, Sigurveig; Department of Engineering
Reykjavik is almost entirely heated by geothermal energy. Yet, recent growth of the city significantly increased the heat demand. Past experiences in Iceland's capital region showed that hydraulic stimulation of existing geothermal wells is suited to improve hydraulic performance and energy supply. However, fluid injection may also trigger felt or even damaging earthquakes, which are of concern in populated areas and pose a significant risk to stimulation operations. Consequently, soft stimulation concepts have been developed to increase geothermal well performance while minimizing environmental effects such as induced seismicity. In a demonstration project of hydraulic soft stimulation in October 2019, more than 20.000 m³ of water were injected into well RV-43 in Reykjavik in multiple stages and with different injection schemes. The hydraulic performance of the well was improved without inducing felt seismicity. An a priori seismic risk assessment was conducted and for the first time the risk was continuously updated by an adaptive traffic light system supported by a sophisticated realtime microseismic monitoring. Our results confirm that it is possible to improve the performance of geothermal wells in Reykjavik and worldwide with acceptable technical, economic, and environmental risks. Here we provide an overview of the entire stimulation project including site description, stimulation design, zonal isolation, logging, seismic risk assessment and mitigation measures, realtime seismic, hydraulic and chemical monitoring, and stimulation results and challenges.
Compact and high gain 4 × 4 circularly polarized microstrip patch antenna array for next generation small satellite
(2021-10-01) Elahi, Manzoor; Trinh-Van, Son; Yang, Youngoo; Lee, Kang Yoon; Hwang, Keum Cheol; Department of Engineering
In this article, a high gain and compact 4 × 4 circularly polarized microstrip patch antenna array is reported for the data transmission of the next-generation small satellite. The radiating element of the circularly polarized antenna array is realized by the conventional model of the patch with truncated corners. A compact two-stage sequential rotational phase feeding is adopted that broadens the operating bandwidth of the 4 × 4 array. A small stub is embedded in the sequential rotational feed, which results in better performance in terms of the S-parameters and sequential phases at the output ports than sequential rotational feed without open stub. A prototype of the array is fabricated and measured. Fulfilling the application requirements of the next-generation small satellites, the array has the left-handed circularly polarized gain of more than 12 dBic with the axial ratio level below 1.5 dB in the ±10◦ angular space with respect to the broadside direction for the whole bandwidth from 8.05 GHz to 8.25 GHz. Moreover, the left-handed circularly polarized gain varies from 15 to 15.5 dBic in the desired band. The radiation patterns are measured; both the co-and X-pol are validated.
Flokkar í Opnum vísindum
Veldu flokk til að skoða.
- University of Iceland
- University of Akureyri
- Bifröst University
- Hólar University College
- IRIS
- Agricultural University of Iceland
- National and University Library of Iceland
- Iceland University of the Arts