Assessment of different pre-treatment methods for the removal of limonene in citrus waste and their effect on methane potential and methane production rate

The objective of this study was to assess the limonene removal efficiency of three pre-treatment methods when applied to citrus waste and to evaluate their effects on the biochemical methane potential (BMP) and the methane production rate (MPR) using batch anaerobic testsPostprint (published version

Optical absorption of divalent metal tungstates: Correlation between the band-gap energy and the cation ionic radius

We have carried out optical-absorption and reflectance measurements at room temperature in single crystals of AWO4 tungstates (A = Ba, Ca, Cd, Cu, Pb, Sr, and Zn). From the experimental results their band-gap energy has been determined to be 5.26 eV (BaWO4), 5.08 eV (SrWO4), 4.94 eV (CaWO4), 4.15 eV (CdWO4), 3.9-4.4 eV (ZnWO4), 3.8-4.2 eV (PbWO4), and 2.3 eV (CuWO4). The results are discussed in terms of the electronic structure of the studied tungstates. It has been found that those compounds where only the s electron states of the A2+ cation hybridize with the O 2p and W 5d states (e.g BaWO4) have larger band-gap energies than those where also p, d, and f states of the A2+ cation contribute to the top of the valence band and the bottom of the conduction band (e.g. PbWO4). The results are of importance in view of the large discrepancies existent in prevoiusly published data.Comment: 16 pages, 3 figures, 1 tabl

Applying A Methodology For Educating Students With Special Needs: A Case Study

The introduction of innovative educational technologies opens up new ways of interacting with students. We propose to exploit this potential to help in the education of children with special needs. We analyze the state of the art of tools supporting the teaching process, focusing on the omissions of existing research. We propose a new framework to help throughout the whole teaching process and describe its application to Proyecto Aprender (Learn Project), an educational resource targeting children with learning difficulties. Finally, we outline some conclusions and current/future research lines

High-pressure study of substrate material ScAlMgO4

We report on the structural properties of ScAlMgO4 studied under quasi-hydrostatic pressure using synchrotron high-pressure x-ray diffraction up to 40 GPa. We also report on single-crystal studies of ScAlMgO4 performed at 300 K and 100 K. We found that the low-pressure phase remains stable up to 24 GPa. At 28 GPa, we detected a reversible phase transformation. The high-pressure phase is assigned to a monoclinic distortion of the low-pressure phase. No additional phase transition is observed up to 40 GPa. In addition, the equation of state, compressibility tensor, and thermal expansion coefficients of ScAlMgO4 are determined. The bulk modulus of ScAlMgO4 is found to be 143(8) GPa, with a strong compressibility anisotropy. For the trigonal low-pressure phase, the compressibility along the c-axis is twice than perpendicular one. A perfect lattice match with ZnO is retained under pressure in the pressure range of stability of wurtzite ZnO.Comment: 22 pages, 5 figures, 4 tables, 24 reference

A Framework to Support Development of Learning Applications for Disabled Children

Multimedia resources are an important tool that can be used by teachers in the classroom as a learning aid for learners with disabilities or by parents and children at home. However, disabled children are not always able to use existing assistive technologies because they are not experienced enough, suffer from medium/profound disability, or simply do not have the financial resources to buy commercial tools. Additionally, today’s adapted tools are not always valid for a broad spectrum of disabled users and often focus on a user group. We claim that potential applications and resources for people with special needs must self-adapt to user capabilities and skills, reducing the use of external assistive technologies. In this paper, we present a guide for developers to create accessible applications and resources that reduce workload

Compressibility and structural stability of ultra-incompressible bimetallic interstitial carbides and nitrides

We have investigated by means of high-pressure x-ray diffraction the structural stability of Pd2Mo3N, Ni2Mo3C0.52N0.48, Co3Mo3C0.62N0.38, and Fe3Mo3C. We have found that they remain stable in their ambient-pressure cubic phase at least up to 48 GPa. All of them have a bulk modulus larger than 330 GPa, being the least compressible material Fe3Mo3C, B0 = 374(3) GPa. In addition, apparently a reduction of compressibility is detected as the carbon content increased. The equation of state for each material is determined. A comparison with other refractory materials indicates that interstitial nitrides and carbides behave as ultra-incompressible materials.Comment: 14 pages, 3 figures, 1 tabl

Aplicació de l’aprenentatge cooperatiu per la realització de pràctiques de laboratori

L’objectiu del projecte és aplicar l’aprenentatge cooperatiu (AC) per la realització de pràctiques de laboratoris. Concretament les pràctiques es realitzen en el laboratori d’audiovisuals i en l’estudi de so de l’EUETIT de Terrassa. Per aquestes pràctiques es requereixen utilitzar molts equips i resulta difícil generar pràctiques engrescadores i interessants. Proposem la utilització de l’AC, concretament el mètode del puzle, per assolir aquest objectiu. Per poder portar a terme l’AC es requereix planificar adequadament les tasques a fer abans i durant la sessió de laboratori. Amb l’ús de l’AC es pretén fomentar l’exigibilitat personal i d’interdependència positiva de forma que cada alumne sigui responsable de l’aprenentatge d’una part d’un instrument o de la seva totalitat segons sigui el cas. S’ha de generar la documentació necessària per que l’alumne sàpiga que ha de fer dintre i fora del laboratori. A més s’ha de generar la documentació que cada alumne s’ha d’estudiar. L’objectiu és generar material audiovisual sempre que sigui possible ja que creient que, per exemple, s’entén millor el funcionament de una taula de mescles d’àudio a partir una bona gravació audiovisual que de la lectura del manual. Es volt estudiar si aquesta hipòtesis és correcte. Per l’avaluació de l’aprenentatge de cada component del grup es volt generar un qüestionari que individualment s’ha de respondre abans de la sessió de laboratori, i per tant, abans de la reunió d’experts i de l’explicació de cada component del grup a la resta dels seus companys de grup. S’han de generar tants qüestionaris com membres hi hagi en el grup. Donat que hi ha cinc grups de pràctiques diferents es volt consensuar els criteris d’avaluació entre el professorat per generar una rúbrica que serà coneguda pels alumnes.Peer Reviewe

High-pressure structural investigation of several zircon-type orthovanadates

Room temperature angle-dispersive x-ray diffraction measurements on zircon-type EuVO4, LuVO4, and ScVO4 were performed up to 27 GPa. In the three compounds we found evidence of a pressure-induced structural phase transformation from zircon to a scheelite-type structure. The onset of the transition is near 8 GPa, but the transition is sluggish and the low- and high-pressure phases coexist in a pressure range of about 10 GPa. In EuVO4 and LuVO4 a second transition to a M-fergusonite-type phase was found near 21 GPa. The equations of state for the zircon and scheelite phases are also determined. Among the three studied compounds, we found that ScVO4 is less compressible than EuVO4 and LuVO4, being the most incompressible orthovanadate studied to date. The sequence of structural transitions and compressibilities are discussed in comparison with other zircon-type oxides.Comment: 34 pages, 2 Tables, 11 Figure