| 1. |
- Abdel-Khalek, Ahmed A., et al.
(författare)
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Chemical Studies on Uranium Extraction from Concentrated Phosphoric Acid by Using PC88A and DBBP Mixture.
- 2011
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Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer. - 0236-5731 .- 1588-2780. ; 290, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- Liquid–liquid extraction of U (VI) from concentrated phosphoric acid by using (2-ethyl hexyl) phosphonic acid, mono (2-ethyl hexyl) ester (PC88A) and di-butyl butyl phosphonate (DBBP) has been investigated. The effect of different factors affecting the extraction process (PC88A concentration, DBBP concentration, shaking time, aqueous/organic phase ratio, phosphoric acid concentration and effect of diluents) have been investigated. The obtained data of temperature on the extraction showed that the enthalpy change is −17.15 kJ mol−1. Uranium was extracted from the strip liquor by using di (2-ethylhexyl) phosphoric acid and tri-octyl phosphine oxide mixture and finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 365 °C.
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| 2. |
- Abdulle, Assyr, et al.
(författare)
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Exponential decay of the resonance error in numerical homogenization via parabolic and elliptic cell problems
- 2019
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Ingår i: Comptes rendus. Mathematique. - : Elsevier BV. - 1631-073X .- 1778-3569. ; 357:6, s. 545-551
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents two new approaches for finding the homogenized coefficients of multiscale elliptic PDEs. Standard approaches for computing the homogenized coefficients suffer from the so-called resonance error, originating from a mismatch between the true and the computational boundary conditions. Our new methods, based on solutions of parabolic and elliptic cell problems, result in an exponential decay of the resonance error.
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| 3. |
- Acuña, José, 1982-, et al.
(författare)
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Distributed thermal response tests on pipe-in-pipe borehole heat exchangers
- 2013
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 109:SI, s. 312-320
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Tidskriftsartikel (refereegranskat)abstract
- Borehole Thermal Energy Storage systems typically use U-pipe Borehole Heat Exchangers (BHE) having borehole thermal resistances of at least 0.06 K m/W. Obviously, there is room for improvement in the U-pipe design to decrease these values. Additionally, there is a need for methods of getting more detailed knowledge about the performance of BHEs. Performing Distributed Thermal Response Tests (DTRT) on new proposed designs helps to fill this gap, as the ground thermal conductivity and thermal resistances in a BHE can be determined at many instances in the borehole thanks to distributed temperature measurements along the depth. In this paper, results from three heat injection DTRTs carried out on two coaxial pipe-in-pipe BHEs at different flow rates are presented for the first time. The tested pipe-in-pipe geometry consists of a central tube inserted into a larger external flexible pipe, forming an annular space between them. The external pipe is pressed to the borehole wall by applying a slight overpressure at the inside, resulting in good thermal contact and at the same time opening up for a novel method for measuring the borehole wall temperature in situ, by squeezing a fiber optic cable between the external pipe and the borehole wall. A reflection about how to calculate borehole thermal resistance in pipe-in-pipe BHEs is presented. Detailed fluid and borehole wall temperatures along the depth during the whole duration of the DTRTs allowed to calculate local and effective borehole thermal resistances and ground thermal conductivities. Local thermal resistances were found to be almost negligible as compared to U-pipe BHEs, and the effective borehole resistance equal to about 0.03 K m/W. The injected power was found to be almost evenly distributed along the depth.
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| 4. |
- Adler-McKean, Jack
(författare)
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The History and Future of the Tuba Family : Material-, Resonance-, and Performance-Based Perspectives
- 2024
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Ingår i: Timbre and Orchestration Writings.
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an examination of the intersections of materiality, acoustics, and musical performance practice through the prism of instruments of the tuba family.[*] Investigation into the symbiotic relationship between instrumental evolution and performance practice is a crucial facet of any study of timbre and orchestration. The development of musical objects to produce the sound colors demanded by aesthetic trends and compositional desires (or vice versa) has an inevitable impact upon both performance and pedagogical traditions. Gone unchecked, such transformations can easily solidify as common practices, and are soon followed unquestioningly by new generations of performers. This can result in a rarefication of the palette of timbres available to musicians, be they interested in evaluating the music of the past or exploring the music of the future.Such a risk is particularly acute in the case of the tuba family, the least-examined subsection of the labrosones (or “brass” instruments), and as such particularly vulnerable to isolationist performance practices.[1] Such “ghettos of interest” (Wills, 1997, p. 176) are reflected in contemporary academic and performance-based practices, implying an urgent need to both propagate an understanding of, and develop a means of knowledge transfer between, the organological, acoustical, physiological, and logistical parameters which define how music is made using instruments of the tuba family. Performance-based historical organology and acoustic analysis can illuminate how an instrument’s history informs discussions concerning the sound colors available to performers and composers. An interdisciplinary critical-experimental approach to a wide range of knowledge sources—from early-nineteenth-century newspaper reports to electro-acoustic organological experimentation—can thus provide a means of examining the complex relationship that performers have with their instruments.Attending to the above assessment, this article demonstrates how analytical processes can be applied to tuba family performance and pedagogical practices, book-ended by two diverse case studies. I first employ a combination of historical organology and practice-based research to illustrate how instruments of the tuba family that preceded the invention of the valve in around 1814 evolved as composers began adopting them into their orchestras. Audio-visual resources are then presented as a means of overcoming entrenched uncritical interpretational traditions. Following this, an overview of twentieth- and twenty-first-century appraisals of the tuba family juxtaposes the benefits provided by an acoustics- and resonance-based analysis of labrosones. This is then demonstrated in my second case study, which presents nascent findings from my ongoing experiments with electroacoustic resonant systems. These examples demonstrate how both historical and analytical organology can be used in combination with artistic research to form a rigorous, historical- and data-driven study that has the potential to have significant impact on contemporary performance practice.
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| 5. |
- Aglert, Katja
(författare)
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“Archipelagic Rehearsals” – Attemptive Thinking Through Practicing Textual Artistic Research
- 2021
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Ingår i: Karib - Nordic Journal for Caribbean Studies. - : Novus Forlag. - 1894-8421 .- 2387-6743. ; 6:1, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- The article is based on a lecture performance titled “Archipelagic Rehearsals – Abstract as Score” that was presented at the RGS-IBG conference, held jointly by the Royal Geographical Society and the Institute of British Geographers, in Cardiff in 2018. The presentation was an exploration of a possibility to practice, in Édouard Glissant’s terms, “archipelagic thinking” by presenting a lecture with interaction from the audience, as a lecture performance. That “archipelagic experiment” is continued in the article through an attempt to format the performance as an academic text. In turn, the text is an attempt to create new imaginaries and storytelling with Spanish slugs through participatory artistic experimental practice. The writing as artistic practice offers the potential for becoming and as such it is unpredictable in its outcome. The article starts with the author’s framing of Glissant’s poetics and attempts a feminist and more-than-human approach to present the event – the performance of the lecture and the story of the slug in footnotes that were an integral part of the lecture.
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| 6. |
- Akbari, Keramatollah, 1961-, et al.
(författare)
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Numerical Simulation of Radon Transport and Indoor Air Conditions Effects
- 2012
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Ingår i: International journal of scientific and Engineering Research. - 2229-5518. ; 3:6, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Computational fluid dynamics (CFD) is a powerful tool for predicting and visualizing radon content and indoor air quality and is cost effective in comparison with other methods such as full scale laboratory and gas trace techniques. The intention of this article is to use CFD to simulate indoor radon distribution and ventilation effects. In this study a mechanically balanced ventilation system and a continuous radon monitor (CRM) were used to measure the indoor ventilation rate and radon levels. In a numerical approach the FLUENT CFD package was used to simulate radon entry into the building and effects on indoor air conditions. The effects of different ventilation rates, indoor temperature and relative humidity on indoor radon concentrations were investigated in a one family de-tached house in Stockholm. Results of numerical studies indicated that changes of ventilation rate, indoor temperature and moisture by means of ventila-tion systems have significant effects on indoor radon content. Ventilation rate was inversely proportional to indoor radon concentration. Minimum radon levels were estimated in the range of thermal comfort, i.e. at 21 and relative humidity between 50-70%. The analytical solution was used to validate numeric results at 3 distinct air change rates. Comparisons between numerical and analytical results showed good agreement but there was poor agreement between simulations and measurement results due to the short measuring period.
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| 7. |
- Akner-Koler, Cheryl, et al.
(författare)
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Aesthetics and nanostructure
- 2011
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Ingår i: International Innovation. - : Research Media. - 2041-4552. ; :6, s. 97-97
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Professors Cheryl Akner-Kohler and Lena Tibell of the Nanoform project describe the artistic methods and benefits that it might afford to both science and society.
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| 8. |
- Alam, Anzar, et al.
(författare)
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Online surface roughness characterization of paper and paperboard using a line of light triangulation technique
- 2012
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:3, s. 662-670
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Tidskriftsartikel (refereegranskat)abstract
- Within both the paper and paperboard industries, real time monitoring and measurement of surface roughness of a paper moving at high velocities is an important and challenging area of research. The uniform surface, for an entire production, can be effectively achieved by monitoring and controlling the paper surface roughness, in real time during the manufacturing steps. Presently the majority of paper industries rely on traditional laboratory profilometers. The obvious limitations of lab profilometers are that these are slow, do not measure the quality of entire reels but rather deal with only a few small pieces of samples taken from the end of the reels and it is difficult to make any possible correction in the productionlines without knowing the online roughness data. To eradicate the disadvantages associated with conventional measurements, an online prototype instrument has been developed that measures the surface roughness during the manufacturing steps, and is based on a line of lighttriangulation technique. The prototype technique will be of assistance in ensuring tight process control in order to maintain both a better and auniform quality throughout the entire production. It measures the whole reel, meter by meter, in traditional units of roughness and is also capable of characterizing the topography in a wide range of wavelength spectra. The article presents the online analyses results obtained from the developed prototype. The real time measurements, in a paperboard pilot mill, have successfully characterized and distinguished 16 different grades of newspaper and paperboard reels including reels which have the same family of quality grades and materials.
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| 9. |
- Alam, Mohammad Anzar, et al.
(författare)
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Limitation of a line-of-light online paper surface measurement system
- 2014
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:8, s. 2715-2724
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Tidskriftsartikel (refereegranskat)abstract
- A new prototype device has been developed based on a laser triangulation principle to measure online surface topography in the paper and paperboard industries. It characterizes the surface in a wide spatial scale of topography from 0.09-10 mm. The prototype's technique projects a narrow line-of-light perpendicularly onto the moving paper-Web surface and scattered reflected light is collected at a low angle, low specular, and reduced coherent length onto the CCD sensors synchronized with the laser sources. The scattering phenomenon determines surface deviations in the z-direction. The full-width, at half-maximum of a laser line in cross section is sensitive in computation of the surface topography. The signal processing aspect of the image processing, for example, threshold and filtering algorithms are also sensitive in estimating the accurate surface features. Moreover, improper light illumination, intensity, reflection, occlusion, surface motion, and noise in the imaging sensor, and so forth, all contribute to deteriorate the measurements. Optical techniques measure the surface indirectly and, in general, an evaluation of the performance and the limitations of the technique are both essential and challenging. The paper describes the accuracy, uncertainty, and limitations of the developed technique in the raw profiles and in terms of the rms roughness. The achieved image subpixel resolution is 0.01 times a pixel. Statistically estimated uncertainty (2σ) in the laboratory environment was found 0.05 μm for a smooth sample, which provides a 95% confidence level in the rms roughness results. The depth of field of the prototype is ~2.4 mm.
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| 10. |
- Alkenäs, Dan, 1962-
(författare)
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Varp och inslag – ett interventyr i musikskapande
- 2023
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Ingår i: HumaNetten. - : Linnaeus University. - 1403-2279. ; :50, s. 7-32
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Artikeln beskriver en konstnärlig studie där jag, i en roll som kompositör och konstnärlig forskare, tillsammans med musiklärare och elever i årskurs sex bland annat undersökte möjligheter att komponera musik utifrån visuella tecken i form av emojis. I studien konstateras att musikskapande inom skolkontext innefattar musikaliska aktiviteter som aktörer upplever vara spännande, fantasifulla, kreativa och lustfyllda, men också konstiga, riskabla och ge upplevelser av olust. Positiva upplevelser av musikskapande uppfattas i studien relatera till faktorer som aktörers upplevelse av mening och förståelse samt trygghet och mod, relation mellan känt och okänt i den musikaliska aktiviteten, ledarens lyhördhet och respekt för pågående sociala processer samt uttryck av individuella intressen och upplevelser, samt tydligt kommunicerat ramverk för musikskapandet – innefattande både givna och fria ramar.
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