9300 research outputs found
Sort by
Modification of brewer’s spent grain after sc-CO2 extraction: improvement of sugar and phenolic compounds release
Get PDFPóster presentado en: EIFS2022, the 2nd Iberian Meeting on Supercritical Fluids (2º Encontro Ibérico de Fluidos Supercríticos / 2º Encuentro Ibérico de Fluidos Supercríticos), to be held on 28.February - 2.March 2022 in Coimbra, Portugal.Brewer ́s spent grain (BSG) is the solid by-product generated in breweries after the
mashing and wort filtration process. It comprises about 85 % of the total by-products,
generating approximately 20 kg per 100 L [1]. BSG presents a valuable chemical
composition with a high content of protein and carbohydrates, 5 % of lipids and an
important source of phenolic compounds. Among the different techniques proposed to
valorize BSG, supercritical CO2 (sc-CO2) has become a promising technology to process
biomass. The main aim of this work was to assess the effect of sc-CO2, after BSG oil
extraction, on the subsequent enzymatic hydrolysis to hydrolyze the polysaccharide
fraction into monomeric sugars by comparing the sugar yields of sc-CO2 and non-scCO2
treated BSG.
After sc-CO2 treatment at 40 MPa and 80 oC, the raffinate obtained was subjected to
enzymatic hydrolysis by cellulase at different enzyme dose. At the sc-CO2 extraction the
carbohydrate fraction remained in the raffinate phase after extraction. Glucose yield
increased with enzyme concentration for non-treated and sc-CO2 treated BSG. Higher
yields of glucose were obtained for sc-CO2 treated compared to non-treated sc-CO2 for all
the enzymes concentrations. The percentage increase in glucose yield for sc-CO2 treated
and non-treated BSG was 8, 14 and 18 % for the three cellulase concentrations essayed
in this work, 0.25, 0.5 and 1 %, respectively. The hydrolysis kinetics for xylose and
arabinose have been also determined for non-treated and sc-CO2 treated BSG at 1 % of
cellulase dose. Although not big differences were observed in the final sugar yield in the
hydrolysates, the initial hydrolysis rate were significant higher for the sc-CO2 treated BSG
than for the untreated samples. The higher enzymatic hydrolysis rate and yield obtained in the raffinate-BSG after sc-
CO2 treatment compared with non-treated BSG could be attributed partially to the removal
of the lipid fraction. As it has been described in literature [2], fats and oils could influence
the susceptibility of carbohydrates to enzymes. This improvement was also due to surface
morphology modification. The structural and chemical changes of untreated and sc-CO2
treated BSG was assessed by scanning electron microscopy and X-ray powder diffraction
(XRD). Although the XRD pattern after sc-CO2 treatment indicated that the pre-treatment
was not strong enough to modify the BSG crystallinity, the raffinate exhibited an irregular
porosity and lamellar structure. sc-CO2 broke partially some structural barriers allowing
a better enzyme access.
Furthermore, some phenolic compounds were determined in the enzymatic hydrolysates
at the end of the hydrolysis by using 1 % of cellulase (Table 1). It was observed that for
p-coumaric acid and ferulic acid, a concentration 31 and 24 % higher, respectively, was
obtained in the BSG hydrolysates after sc-CO2 treatment, while for vanillin similar
concentration was obtained in both hydrolysates. The concentration of p-coumaric acid
and vanillin after cellulase hydrolysis was lower than the values previously reported for
the same BSG by alkaline, xylanase (1%) and subcritical water hydrolysis [3], [4].
Nevertheless, for ferulic acid, only a higher value was reached for alkaline hydrolysis.JCyL and ERDF for financial support of project BU050P20
Agencia Estatal de Investigación for financial support of project PID2019-104950RB-I00 / AEI / 10.13039/501100011033
JCyL and ESF for E. Trigueros (ORDEN EDU/574/2018) and P. Alonso-Riaño predoctoral (EDU/556/2019) contracts
R. Melgosa is supported by a Beatriz Galindo Research Fellowship [BG20/00182
Semi-flowable Zn semi-solid electrodes as renewable energy carrier for refillable Zn–Air batteries
Get PDFToday’s society relies on energy storage on a day-to-day basis, e.g. match energy production and demand from renewable sources, power a variety of electronics, and
enable emerging technologies. As a result, a vast range of energy storage technologies has emerged in the last decades. Among them, rechargeable Zn–Air batteries
have held great promises for a long time. However, the severe challenges related to the reversible O2 reactions and poor cyclability at the positive and negative
electrodes, respectively, have severely hindered the success of this technology. Herein, electrically-conducting and semi-flowable Zn semi-solid electrodes are
proposed to revive the appealing concept of a mechanically–rechargeable alkaline Zn–Air battery, in which the spent negative electrodes are easily substituted at the
end of the discharge process (refillable primary battery). In this proof-of-concept study energy densities of ca. 1500 Wh L− 1 (1350 Ah L− 1
electrode and utilization rate of
85%) are achieved thanks to the compromised flowability of the proposed Zn semi-solid electrodes. In this way, semi-solid Zn electrodes become a type of green
energy carrier having intrinsic advantages over gas and liquid fuels. Zn semi-flowable electrode can be generated elsewhere using renewable sources, easily stored,
transported, and used to produce electricity.The project leading to these results has received funding from “la Caixa” Foundation, under agreement LCF/PR/PR18/51130007” and the Spanish Government through the Research Challenges Programme (Grant RTI2018-099228-A-I00). E.V. thanks the MINECO for the financial support (RYC2018-026086-I)
Virtual Reality Training Application for the Condition-Based Maintenance of Induction Motors
Get PDFThe incorporation of new technologies as training methods, such as virtual reality (VR),
facilitates instruction when compared to traditional approaches, which have shown strong limitations
in their ability to engage young students who have grown up in the smartphone culture of continuous entertainment. Moreover, not all educational centers or organizations are able to incorporate
specialized labs or equipment for training and instruction. Using VR applications, it is possible
to reproduce training programs with a high rate of similarity to real programs, filling the gap in
traditional training. In addition, it reduces unnecessary investment and prevents economic losses,
avoiding unnecessary damage to laboratory equipment. The contribution of this work focuses on the
development of a VR-based teaching and training application for the condition-based maintenance of
induction motors. The novelty of this research relies mainly on the use of natural interactions with
the VR environment and the design’s optimization of the VR application in terms of the proposed
teaching topics. The application is comprised of two training modules. The first module is focused
on the main components of induction motors, the assembly of workbenches and familiarization with
induction motor components. The second module employs motor current signature analysis (MCSA)
to detect induction motor failures, such as broken rotor bars, misalignments, unbalances, and gradual
wear on gear case teeth. Finally, the usability of this VR tool has been validated with both graduate
and undergraduate students, assuring the suitability of this tool for: (1) learning basic knowledge
and (2) training in practical skills related to the condition-based maintenance of induction motors.This research has been partially supported by Banco Santander under the scholarship program Santander Iberoamérica Research 2019/20. This investigation was partially supported by the ACIS project (Reference Number INVESTUN/21/BU/0002) of the Consejeria de Empleo of the Junta de Castilla y León (Spain)
Machine Learning-Based View Synthesis in Fourier Lightfield Microscopy
Get PDFCurrent interest in Fourier lightfield microscopy is increasing, due to its ability to acquire
3D images of thick dynamic samples. This technique is based on simultaneously capturing, in a single
shot, and with a monocular setup, a number of orthographic perspective views of 3D microscopic
samples. An essential feature of Fourier lightfield microscopy is that the number of acquired views is
low, due to the trade-off relationship existing between the number of views and their corresponding
lateral resolution. Therefore, it is important to have a tool for the generation of a high number
of synthesized view images, without compromising their lateral resolution. In this context we
investigate here the use of a neural radiance field view synthesis method, originally developed for its
use with macroscopic scenes acquired with a moving (or an array of static) digital camera(s), for its
application to the images acquired with a Fourier lightfield microscope. The results obtained and
presented in this paper are analyzed in terms of lateral resolution and of continuous and realistic
parallax. We show that, in terms of these requirements, the proposed technique works efficiently in
the case of the epi-illumination microscopy mode.This research was funded by Grant RTI2018-099041-B-I00, which is co-founded by the Ministerio de Ciencia, Innovacion y Universidades (Spain), by the European Regional Development Fund, and by Generalitat Valenciana (Spain) under Grant PROMETEO/2019/048
Political directors and corporate social responsibility: Are political ideology and regional identity relevant?
Get PDFThis study analyzes the infuence of directors with political connections on corpo‑
rate social responsibility (CSR). Using a sample of Spanish savings banks (cajas)
during the period 2004–2013, we analyze the infuence of political directors on the
CSR of these entities, focusing on their ideology and regional identity. Our results
indicate that the higher the proportion of directors with political ties on the board,
the greater the allocation of resources to CSR activities. In addition to this positive
efect of board politicization, we fnd that political directors’ liberal ideology posi‑
tively afects CSR, both directly and in moderating the relationship between political
directors and CSR. Our results also validate that political directors’ regional iden‑
tity boosts the positive efect they have on CSR. Finally, we encounter various dif‑
ferences depending on the nature of the projects funded through CSR. Therefore,
our study demonstrates the importance of delving into the characteristics of political
directors to elucidate their efects on corporate policies.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This study was supported by the Spanish Ministry of Economy and Competitiveness (Grant ECO201785356), the UAM - Comunidad de Madrid (SI3-PJI-2021-00276) and it benefted from the Professorship Excellence Program in accordance with the multi-year agreement signed by the Government of Madrid and the Autonomous University of Madrid (Line #3)
Selection of investment portfolios with social responsibility: a multiobjective model and a Tabu search method
Get PDFIn this study, a model for the selection of investment portfolios is proposed with three objectives. In addition to the traditional
objectives of maximizing profitability and minimizing risk, maximization of social responsibility is also considered. Moreover,
with the purpose of controlling transaction costs, a limit is placed on the number of assets for selection. To the best of our
knowledge, this specific model has not been considered in the literature to date. This model is difficult (NP-Hard), and therefore,
only very small instances may be solved in an exact way. This paper proposes a method based on tabu search and multiobjective
adaptive memory programming (MOAMP) strategies. With this method it is possible to obtain sets of nondominated solutions in
short computational times. To check the performance of our method it is compared with adaptations of the nondominated sorting
genetic algorithm (NSGA-II), strength Pareto evolutionary algorithm (SPEA-II) and multiobjective particle swarm optimization
(MOPSO). The results of different computational experiments show that our tabu search-MOAMP method performed best. The
quality of the sets of solutions that were obtained and the speed of execution mean that our tabu search-MOAMP can be used as a
tool for financial assessment and analysis (including online services). This tool, as we can see in this work with some examples,
can take into account the social concerns of many clients and their overall risk profile (very conservative, conservative, moderate,
or fearless). This approach is also in line with current legal regulations that oblige financial advisors to take the client profile into
account to provide greater protection and propose good financial advice.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was partially supported by FEDER funds and the Spanish Ministry of Economy and Competitiveness (Projects PID2019-104263RB-C44 and PDC2021– 121021-C22), the Regional Government of “Castilla y León”, Spain (Projects BU329U14 and BU071G19), the Regional Government of “Castilla y León” and FEDER funds (Projects BU062U16, COV2000375 and BU056P20)
Photocatalytic Aerobic Dehydrogenation of N-Heterocycles with Ir(III) Photosensitizers Bearing the 2(2′-Pyridyl)benzimidazole Scaffold
Get PDFPhotoredox catalysis constitutes a very powerful tool in
organic synthesis, due to its versatility, efficiency, and the mild conditions
required by photoinduced transformations. In this paper, we present an
efficient and selective photocatalytic procedure for the aerobic oxidative
dehydrogenation of partially saturated N-heterocycles to afford the respective
N-heteroarenes (indoles, quinolines, acridines, and quinoxalines). The
protocol involves the use of new Ir(III) biscyclometalated photocatalysts
of the general formula [Ir(C^N)2(N^N′)]Cl, where the C^N ligand is 2-
(2,4-difluorophenyl)pyridinate, and N^N′ are different ligands based on the
2-(2′-pyridyl)benzimidazole scaffold. In-depth electrochemical and photophysical studies as well as DFT calculations have allowed us to establish
structure−activity relationships, which provide insights for the rational design
of efficient metal-based dyes in photocatalytic oxidation reactions. In
addition, we have formulated a dual mechanism, mediated by the radical
anion superoxide, for the above-mentioned transformations.We acknowledge the financial support provided by the Spanish Ministerio de Ciencia, Innovación y Universidades (RTI2018- 100709-B-C21 and CTQ (QMC)-RED2018-102471-T), Consejería de Educación de la Junta de Castilla y León and FEDER (BU087G19 and BU067P20), and Junta de Comunidades de Castilla-La Mancha-FEDER (JCCM) (grant SBPLY/19/ 180501/000260). I.E. acknowledges his fellowship to both the European Social Fund and Consejería de Educación de la Junta de Castilla y León (EDU/1100/2017). We are also indebted to J. Delgado, P. Castroviejo, and M. Mansilla (PCT of the Universidad de Burgos) for technical support, G. GarcíaHerbosa for providing us access to CV equipment, and J. V. Cuevas-Vicario for support with Gaussian
The End-Purpose of Teaching Social Sciences and the Curricular Inclusion of Social Problems
Get PDFArtículo editorial del número especial dedicado a The End-Purpose of Teaching Social Sciences and the Curricular Inclusion of Social ProblemsThe most recent scientific literature on the treatment of social problems or controversial social questions in the social sciences classroom and their inclusion into curricula emphasizes the need to introduce students into large-scale social debates where different points of view exist, different interests are at stake, and where it is desirable that they construct their own opinions in that respect from a critical and reasoned perspective. Research on social problems permits a typology of analysis that includes the relative experience of the past and the expectations for the future in a present that is lived and to consider the temporal relation on the basis of an analysis of changes and continuities that are observable from a comparative perspective. In the comprehension and interpretation of the historicity of the present and in planning the social future, social problems would have to represent a fundamental curricular tenant that gives relevance to the contemporaneousness of the student.Research Group Recognized in Didactics of History and Social Sciences (DHISO), and the Group for Educational Innovation in Didactics of Social Sciences, Languages, and Literatures in Initial Teacher Training of Early Childhood Education and Primary Education (DiCSOL) of the University of Burgos. This publication is part of the R&D Project Teach and Learn to interpret contemporary problems and conflicts. What do the Social Sciences contribute to the formation of a critical global citizenship? (EDU2016-80145-P), financed by the Ministry of Economy and Competitiveness (Spanish Government), and Future Education and Democratic Hope. Rethinking Social Studies Education in changing times (PID2019-107383RB-I00), financed by the Ministry of Science, and Innovation (Spanish Government)
A Low-Cost Luxometer Benchmark for Solar Illuminance Measurement System Based on the Internet of Things
Get PDFNatural illumination has an important place in home automation applications. Among
other advantages, it contributes to better visual health, energy savings, and lower CO2 emissions.
Therefore, it is important to measure illuminance in the most accurate and cost-effective way. This
work compares several low-cost commercial sensors (VEML 7700, TSL2591, and OPT3001) with a
professional one (ML-020S-O), all of them installed outdoors. In addition, a platform based on the
Internet of Things technology was designed and deployed as a centralized point of data collection and
processing. Summer months have been chosen for the comparison. This is the most adverse situation
for low-cost sensors since they are designed for indoor use, and their operating range is lower than
the maximum reached by sunlight. The solar illuminance was recorded every minute. As expected,
the obtained bias depends on the solar height. This can reach 60% in the worst circumstances,
although most of the time, its value stays below 40%. The positive side lies in the good precision of
the recordings. This systematic deviation makes it susceptible to mathematical correction. Therefore,
the incorporation of more sensors and data that can help the global improvement of the precision
and accuracy of this low-cost system is left as a future line of improvement.The authors gratefully acknowledge the financial support provided by the Spanish Ministry of Science & Innovation under the I+D+i state program “Challenges Research Projects” (RTI2018-098900-B-I00) and the Regional Government of Castilla y León (IN-VESTUN/19/BU/004 and INVESTUN/22/BU/0001). Diego Granados López also thankfully acknowledges the financial support from the Junta de Castilla-León (ORDEN EDU/556/2019)