2,219 research outputs found
Washing machine dynamic model to prevent tub collision during transient state
In horizontal-axis washing machines, the front gasket as well as the damping system are crucial owing to the possible collision of the tub with the housing during the transient period. However, most dynamic models for predicting tub motion focus on the steady state and consider only the suspension system without including the gasket. We conducted an experimental study to analyze the effect of the gasket on the transient motion of the tub. The results obtained indicate the necessity of implementing the gasket in the multibody model of a washing machine to accurately predict the tub behavior during this period. The gasket model is formed by a combination of Voigt elements. Stiffness parameters are determined using a load cell, and damping factors are estimated using a process that integrates Adams/View, Matlab optimization algorithms, and displacement measurements that are taken using accelerometers. A D-optimal design used to predict the effect of the gasket parameters reveals that the tub displacement is most sensitive to the changes in linear stiffness in the transversal direction. Finally, the model of the gasket provides a better approach for predicting the tub movement during resonance that can be used in the design phase to avoid tub collision
Analysing discussions in social networks using group decision making methods and sentiment analysis
Social networks are one of the most preferred environments for people to carry
out debates. Due to the fact that a high amount of people can participate
in the process, there is a need of tools that can analyse these discussions
and extract useful information from them. In this paper, a novel way of
determining how the debate is going on, if there is consensus among the
participants and which alternatives are preferred is presented. Sentiment
analysis is used in order to measure the level of preference that social media
users have about a certain set of alternatives. In order to test the presented
scheme, a real application example that makes use of Twitter information is
presentedThis paper has been developed with the financing of FEDER funds in the project TIN2016-75850-
Unusual flexibility of mesophase pitch-derived carbon materials:an approach to the synthesis of graphene
Structural flexibility in a petroleum pitch-derived carbon material has been indirectly evaluated using X-ray diffraction (XRD), immersion calorimetry and inelastic neutron scattering (INS) measurements. Exposure of the carbon material to an organic solvent (e.g., n-nonane) gives rise to a large internal rearrangement, associated with a drastic re-ordering of the graphitic microdomains. These structural changes are also associated with a high flexibility of the internal porous network, as observed by inelastic neutron scattering measurements. The internal rearrangement and the structural flexibility could be responsible for the excellent performance of this kind of activated carbons in a wide variety of adsorption processes. Last but not least, the structural characteristics of these carbon materials composed of graphitic microdomains has been used to synthesize graphene “egg-like” flakes following a simple procedure based on exfoliation with organic solvents
Solid-phase microextraction-liquid chromatography-mass spectrometry applied to the analysis of insecticides in honey
Hipotiroidismo subclínico y factores de riesgo cardiovascular
Objetivo: Conocer la prevalencia del hipotiroidismo
subclínico en la población general de un centro de salud
urbano y describir las características clínicas y factores
de riesgo cardiovascular de los pacientes con hipotiroidismo
subclínico.
Métodos: Se realizó un estudio observacional descriptivo,
transversal, retrospectivo, revisando las historias clínicas
de los pacientes incluidos en la muestra desde junio de 2005
hasta julio de 2007. Se analizaron las siguientes variables;
Datos generales: edad y sexo. Antecedentes familiares:
patología tiroidea y otras enfermedades. Antecedentes personales:
cardiovasculares, pulmonares, enfermedades
autoinmunes, alteraciones gineco-obstétricas, diabetes,
hipertensión (HT), dislipemia, obesidad, alteraciones psiquiátricas
y hematológicas. Datos de laboratorio: niveles
de TSH, niveles de T4 libre,presencia de anticuerpos antiperoxidasa,
niveles de colesterol total y sus fracciones.
Resultados: La prevalencia de la muestra de 100
pacientes recogida durante 8 meses fue de 3,8% de la
población general mayor de 14 años, de la cual 79 eran
mujeres y 21 eran hombres. El 13% eran diabéticos tipo
2, 23% tenían HT y un 40% tenían dislipemia. Sobrepeso
y obesidad estaban presentes en un 26%. El nivel medio
de TSH fue 6.92 ± 2,29 U/ml y el nivel medio de T4 libre
fue 1,16 ± 0,16 ng/ml.
Conclusiones: La prevalencia del hipotiroidismo subclínico
fue 3,8%. sobre todo en mujeres con una edad
media de 46 años. La incidencia de factores de riesgo cardiovascular
en los sujetos estudiados es mayor en DM
(13%), similar a la población general en cuanto a la dislipemia
(40%) y obesidad (20%) y menor en HTA (23%).
En nuestro estudio no se observa una pauta común en
el manejo del hipotiroidismo subclínico, siendo necesaria
la implementación y promoción de guías de actuación en
Atención PrimariaObjective: To determine the prevalence of subclinical
hypothyroidism in the general population of an urban
health center and describe the clinical characteristics and
cardiovascular risk factors in patients with subclinical
hypothyroidism.
Methods: An observational study, retrospective, reviewing
the medical histories of patients sampled from June
2005 until July 2007. We analyzed the following variables;
facts: age and sex. Family history thyroid disease
and other diseases. Personal history: cardiovascular pulmonary
autoimmune, alterations gynecology obstetric
diabetes, hypertension (HT) dislipemia, obesity, psychiatric
alterations and haematological. Laboratory data:
novel TSH, free T4, antiperoxidase antibodies, total cholesterol
and its fractions.
Results: The prevalence of the sample of 100 patients
collected over 8 months was 3.8% in the general population
over 14 years, of which 79 were women and 21 were
men. 13% were type 2 diabetics, 23% had HT and 40%
had dyslipidemia. Overweight and obesity were present
in 26%. The average level of TSH was 6.92 ± 2.29 U/ml
and the average level of free T4 was 1.16 ± 0.16 ng/ml.
Conclusions: Prevalence subclinical hypothyroidism
was 3.8%. especially in women with a mean age of 46. The
incidence of cardiovascular risk factors in the subjects
studied is higher in DM (13%), similar to general population
in terms of dyslipidemia (40%) and obesity (23%)
and lowest in hypertension (23%). In our study we observed
a common pattern in the management of subclinical
hypothyroidism, requiring the implementation and promotion
of practice guidelines in primary car
Low cost production of computer-generated holograms: from design to optical evaluation
In this work we review some optical characterization methods useful for the low cost production of two phase level computer generated holograms (CGH). As an example, binary CGH are designed with an iterative Fourier transform algorithm (IFTA) and fabricated on a silicon master micromachining with a single step of selective dry etch of silicon dioxide (SiO2) layer. The CGH characterization is performed in three steps; a first one involves the application of spectroscopic ellipsometry measurements to accurately measure the thickness of the SiO2 layer. These results permit the evaluation of the relative complex reflectance between the two levels of the developed hologram as a function of the wavelength. In a second step, interference microscopy is applied to directly visualize the phase shift in the SiO2/Si binary phase profile. Finally, the performance and diffraction efficiency of the fabricated CGH is compared for various lasers with different wavelengths. These experimental measurements in these two last steps confirm with very good accuracy the results derived from the spectroscopic ellipsometry analysis. In conjunction, the combination of these well established optical techniques provides a precise optical characterization of binary diffractive optical elements produced with simple and low cost technique, useful for mass production
Resultados medidos con captura de movimiento en las fracturas de húmero proximal tratadas mediante osteosíntesis con placa bloqueada
Objective: To evaluate the results after locking plate internal fixation of proximal humerus fractures by means of a motion capture system, and functional scales.
Material and method: Retrospective study of a cohort of 47 elderly patients undergoing surgery from January 2010 to December 2014. After a minimum follow-up of two years, two functional scales (Constant-Murley and Quick DASH), and a quality of life scale (EQ-5D) were used for clinical evaluation. For objective evaluation of the range of motion a kinematic marker-free analysis with cameras was performed.
Results: The average age was 74.85 years. Average functional scores were: Constant-Murley 70.06 points, Quick DASH 35.74 points and EQ-5D 6.79 points. The average range of motion was: flexion, 111.49°; extension: 24.13°; abduction: 109.40°; adduction: 15.13°; external rotation: 38.96°, and internal rotation: 49.28°. Correlation was found between the two functional scales, between them and the EQ-5D, and between range of motion and functional scales (except for external rotation) as well as between range of motion and EQ-5D (except for flexion and external rotation).
Conclusion: Locking plate osteosynthesis in proximal humerus fragility fractures achieved good functional and quality of life scores. Motion capture systems can be a useful tool for the functional assessment of shoulder pathology allowing an objective evaluation of range of motion
Turning Carbon Dioxide and Ethane into Ethanol by Solar-Driven Heterogeneous Photocatalysis over RuO2- and NiO-co-Doped SrTiO3
[EN] The current work focused on the sunlight-driven thermo-photocatalytic reduction of carbon dioxide (CO2), the primary greenhouse gas, by ethane (C2H6), the second most abundant element in shale gas, aiming at the generation of ethanol (EtOH), a renewable fuel. To promote this process, a hybrid catalyst was prepared and properly characterized, comprising of strontium titanate (SrTiO3) co-doped with ruthenium oxide (RuO2) and nickel oxide (NiO). The photocatalytic activity towards EtOH production was assessed in batch-mode and at gas-phase, under the influence of different conditions: (i) dopant loading; (ii) temperature; (iii) optical radiation wavelength; (vi) consecutive uses; and (v) electron scavenger addition. From the results here obtained, it was found that: (i) the functionalization of the SrTiO3 with RuO2 and NiO allows the visible light harvest and narrows the band gap energy (ca. 14-20%); (ii) the selectivity towards EtOH depends on the presence of Ni and irradiation; (iii) the catalyst photoresponse is mainly due to the visible photons; (iv) the photocatalyst loses > 50% efficiency right after the 2nd use; (v) the reaction mechanism is based on the photogenerated electron-hole pair charge separation; and (vi) a maximum yield of 64 mu mol EtOH g(cat)(-1) was obtained after 45-min (85 mu mol EtOH g(cat)(-1) h(-1)) of simulated solar irradiation (1000 W m(-2)) at 200 degrees C, using 0.4 g L-1 of SrTiO3:RuO2:NiO (0.8 wt.% Ru) with [CO2]:[C2H6] and [Ru]:[Ni] molar ratios of 1:3 and 1:1, respectively. Notwithstanding, despite its exploratory nature, this study offers an alternative route to solar fuels' synthesis from the underutilized C2H6 and CO2.This work was financially supported by the Base Funding-UIDB/50020/2020 of the Associate Laboratory LSRE-LCM-funded by national funds through FCT/MCTES (PIDDAC). Larissa O. Paulista also wants to acknowledge for her doctoral fellowship (reference SFRH/BD/137639/2018), supported by FCT. Tania F. C. V. Silva and Vitor J. P. Vilar acknowledge the FCT Individual Call to Scientific Employment Stimulus 2017 (CEECIND/01386/2017 and CEECIND/01317/2017, respectively). Josep Albero and Hermenegildo Garcia are also grateful to the Spanish Ministry of Science and Innovation (RTI2018-098237-CO2-R1 and Severo Ochoa), Generalitat Valencia (Prometeo 2017/083) and European Union's Horizon 2020 research and innovation programme under grant agreement No 862453, project FlowPhotochem, by financial contribution.Paulista, LO.; Albero-Sancho, J.; Martins, RJE.; Boaventura, RAR.; Vilar, VJP.; Silva, TFCV.; García Gómez, H. (2021). Turning Carbon Dioxide and Ethane into Ethanol by
Solar-Driven Heterogeneous Photocatalysis over RuO2- and
NiO-co-Doped SrTiO3. Catalysts. 11(4):1-18. https://doi.org/10.3390/catal1104046111811
Estudio de la reacción entre el Hg(l) y el ácido etilenglicol bis (β-amino etil éter) tetraacético. Determinación espectrofotométrica de Hg22+
The reaction between Hg(I) and ethyleneglycol bis (β-aminoethylether)- N, N, N3, N3 tetraacetate (EGTA) in a weakly acidic médium (pH ≈ 5) is studied by U. V. spectrophotometric techniques. The maxiraum of absorption which appears at 247 nm is supposed due to the formation of a Hg(I) - EGTA complex. This compotmd is unstable and it decomposes slowly with formation of Hg(II) chelate and metallic mercury. When the absorbance is measured at fixed time (5 minutes), it is fovmd that Beer's law is obeyed from 1 up to 30 p p m of Hg(I) at 247 nm
Unusual flexibility of mesophase pitch-derived carbon materials:an approach to the synthesis of graphene
Structural flexibility in a petroleum pitch-derived carbon material has been indirectly evaluated using X-ray diffraction (XRD), immersion calorimetry and inelastic neutron scattering (INS) measurements. Exposure of the carbon material to an organic solvent (e.g., n-nonane) gives rise to a large internal rearrangement, associated with a drastic re-ordering of the graphitic microdomains. These structural changes are also associated with a high flexibility of the internal porous network, as observed by inelastic neutron scattering measurements. The internal rearrangement and the structural flexibility could be responsible for the excellent performance of this kind of activated carbons in a wide variety of adsorption processes. Last but not least, the structural characteristics of these carbon materials composed of graphitic microdomains has been used to synthesize graphene “egg-like” flakes following a simple procedure based on exfoliation with organic solvents
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