Scalable Bacterial Cellulose-Based Radiative Cooling Materials with Switchable Transparency for Thermal Management and Enhanced Solar Energy Harvesting

Radiative cooling materials that can dynamically control solar transmittance and emit thermal radiation into cold outer space are critical for smart thermal management and sustainable energy-efficient buildings. This work reports the judicious design and scalable fabrication of biosynthetic bacterial cellulose (BC)-based radiative cooling (Bio-RC) materials with switchable solar transmittance, which are developed by entangling silica microspheres with continuously secreted cellulose nanofibers during in situ cultivation. Theresulting film shows a high solar reflection (95.3%) that can be facilely switched between an opaque state and a transparent state upon wetting. Interestingly, the Bio-RC film exhibits a high mid-infrared emissivity (93.4%) and an average sub-ambient temperature drop of ≈3.7 °C at noon. When integrating with a commercially available semi-transparent solar cell, the switchable solar transmittance of Bio-RC film enables an enhancement of solar power conversion efficiency (opaque state: 0.92%, transparent state: 0.57%, bare solar cell: 0.33%). As a proof-of-concept illustration, an energy-efficient model house with its roof built with Bio-RC-integrated semi-transparent solar cell is demonstrated. This research can shine new light on the design and emerging applications of advanced radiative cooling materials.     

Feedback linearization control for a distributed solar collector field

This article describes the application of a feedback linearization technique for control of a distributed solar collector field using the energy from solar radiation to heat a fluid. The control target is to track an outlet temperature reference by manipulating the fluid flow rate through the solar field, while attenuating the effect of disturbances (mainly radiation and inlet temperature). The proposed control scheme is very easy to implement, as it uses a numerical approximation of the transport delay and a modification of the classical control scheme to improve startup in such a way that results compared with other control structures under similar conditions are improved while preserving short commissioning times. Experiments in the real plant are also described, demonstrating how operation can be started up efficiently.     

Perception of cognitive function in older adults following coronary artery bypass surgery.

This study examined the effects of coronary artery bypass grafting (CABG) on objective and subjective measures of neurocognitive functioning. Participants were 170 older patients (127 men and 43 women; mean age?=?61 years) undergoing CABG. Measures of neurocognitive function, depression, anxiety, and perceived cognitive abilities were administered immediately prior to and 6 weeks following surgery. Although objective measures of impaired cognitive performance following CABG were not related to perceived cognitive difficulties, the presence of anxiety and depression was related to the perception of cognitive functioning. Patients who reported high levels of anxiety and depression 6 weeks after surgery perceived themselves as having poorer cognitive function. Interventions designed to reduce emotional distress could improve patient's perceived cognitive abilities following CABG. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermodynamic properties of moisture desorption of raw pinhão (Araucaria angustifolia seeds)

The seeds of Araucaria angustifolia, named pinhão, are consumed in the south and southeast of Brazil. They are big in size and have high nutritious value. The literature about technological aspects of pinhão is very scarce and there are no reports about moisture sorption models. In this work, moisture desorption isotherms of raw pinhão were determined at 15, 25, 30 and 40 °C. Results show that temperature has little effect on the sorption behaviour and the Chirife model was found to best represent the experimental data. The isosteric heat of sorption (differential enthalpy) was calculated through direct use of moisture desorption isotherm by applying the Clausius‐Clapeyron equation. The differential enthalpy of desorption decreased with increasing moisture content. The enthalpy–entropy compensation theory was applied to desorption isotherms and plots of differential enthalpy vs. differential entropy for pinhão provided the isokinetic temperature, indicating an enthalpy‐controlled desorption process.     

Degree of appropriateness and frequency of consumption of mayonnaise, ketchup, mustard and similar sauces in Argentina

The objectives of this study were to measure the appropriateness and frequency of consumption of five moist seasoning sauces (SS) for 16 different uses, and to analyze the relationship between these two measures. SS were golf sauce, ketchup, mayonnaise, mustard and “mostanesa” (mustard + mayonnaise). A total of 240 subjects, distributed in two cities, of three age groups and two genders performed the measurements. Mayonnaise was the SS considered most appropriate and consumed most frequently. For the average subject appropriateness was a valid predictor of frequency of consumption, but this prediction was not uniform over different seasoning sauces. When each individual subject was considered the correlation between frequency of consumption and appropriateness was not good: some consumed what they thought appropriate, but others consumed SS with low appropriateness, and others did not consume what they thought appropriate. Subjects were clustered according to what they consider appropriate and consume and not according to where they live, their age or gender.     

Precise Incident Power Density Pattern Measurement through Antenna Pattern Deconvolution

Future cellular and fixed wireless loops (FWL) systems employing highlydirective base stations antennas (5 to 8 degrees beamwidth) and moderatelydirective subscribers' antennas (15 to 25 degrees beamwidth) offer very largecapacity due to reduced interference. An important property of the environmentof such systems is the interference caused by scattering of the signal froma subscriber transmitter into directions other than the direct line of sightbetween the subscriber and the base station. In particular, for multibeam basestation applications scattering could arrive at the base station in thedirection being used by a different beam, resulting in interference that isdifficult to reduce by normal nulling techniques. Thus interference can behighly dependent on the incident power density pattern (IPDP) caused byscattering of the signal radiated from the subscriber. We discuss herein theuse of a uniformly illuminated array accompanied by electric fielddeconvolution to measure the crucial IPDP with the same performance as a lowsidelobe array of the same size. The mathematical correction technique usesdeconvolution of the measured complex electric field pattern with that of theantenna in free space by means of the Fourier Series and limiting the rangeof Fourier coefficients to those that are not negligible in the free spacepattern. Application of the technique to an experimental uniform array witha 2.5 degree azimuthal beamwidth shows the practicality of the deconvolutionwith real antennas in real environments. The improved resolution and accuracyprovided by Taylor weighting versus unweighted deconvolution when trying tomeasure weak scattered components in the presence of a nearby strong specularcomponent is demonstrated. The IPDP was measured from many sites surroundinga suburban base station. A plot of the cumulative distribution of the ratioof the widely scattered power to that within a prescribed beamwidth summarizesthe result of using the deconvolution technique on this experimental data.     

Ni/Ce-MCM-41 mesostructured catalysts for simultaneous production of hydrogen and nanocarbon via methane decomposition

For the first time, simultaneous production of hydrogen and nanocarbon via catalytic decomposition of methane over Ni-loaded mesoporous Ce-MCM-41 catalysts was investigated. The catalytic performance of the Ni/Ce-MCM-41 catalysts is very stable and the reaction activity remained almost unchanged during 1400 min steam on time at temperatures 540, 560 and 580 °C, respectively. The methane conversion level over these catalysts reached 60–75% with a 100% selectivity towards hydrogen. TEM observations revealed that most of the Ni particles located on the tip of the carbon nanofibers/nanotubes in the used catalysts, keeping their exposed surface clean during the test and thus remaining active for continuous reaction without obvious deactivation. Two kinds of carbon materials, graphitic carbon (C_g) as major and amorphous carbon (C_A) as minor were produced in the reaction, as confirmed by XRD analysis and TEM observations. Carbon nanofibers/nanotubes had an average diameter of approximately 30–50 nm and tens micrometers in length, depending on the reaction temperature, reaction time and Ni particle diameter. Four types of carbon nanofibers/nanotubes were detected and their formations greatly depend on the reaction temperature, time on steam and degree of the interaction between the metallic Ni and support. The respective mechanisms of the formation of nanocarbons were postulated and discussed.     

Development and validation of an LC-MS/MS method for the quantification of tiamulin,trimethoprim, tylosin,sulfadiazine and sulfamethazine in medicated feed

A new multi-compound method for the analysis of veterinary drugs, namely tiamulin, trimethoprim, tylosin, sulfadiazine and sulfamethazine was developed and validated in medicated feeds. After extraction, the samples were centrifuged, diluted in Milli-Q water, filtered and analysed by high performance liquid chromatography coupled to tandem mass spectrometry. The separation of the analytes was performed on a biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/EC. Method performances were evaluated by the following parameters: linearity (R² < 0.99), precision (repeatability <14% and within-laboratory reproducibility <24%), recovery (73.58–115.21%), sensitivity, limit of detection (LOD), limit of quantification (LOQ), selectivity and expanded measurement uncertainty (k. = 2). The validated method was successfully applied to the 2 medicated feeds obtained from the interlaboratory studies and feed manufactures from Spain in August 2017. In these samples, tiamulin, tylosin and sulfamethazine were detected at the concentration levels declared by the manufacturers. The developed method can therefore be successfully used to routinely control the content and homogeneity of these antibacterial substances in medicated feed.

Abbreviations

AAFCO – Association of American Feed Control Officials; TYL – tylosin; TIAM – tiamulin fumarate; TRIM – trimethoprim; SDZ – sulfadiazine; SMZ – sulfamethazine; UV – ultraviolet detector; FLD – fluorescence detector; HPLC – high performance liquid chromatography; MS/MS – tandem mass spectrometry; LOD – limit of detection; LOQ – limit of quantification; CV – coefficient of variation; SD – standard deviation; U – uncertainty