Search

Coffee beverages are renowned for their complex chemical composition and sensory attributes. The Koar® filter holder, developed in Brazil, is an extraction method which utilizes percolation and is available in acrylic, stainless steel, ceramic, and porcelain variations. Thus, this study aimed to investigate how the manufacturing materials of Koar® filter holders impact the sensory profile of coffee beverages, as perceived by consumers. A group of 100 consumers were used, and the methods of check all that apply (CATA), and acceptance testing were applied. The results revealed significant variations in eight sensory attributes assessed by consumers. The beverages prepared with ceramic and porcelain filter holders exhibited similar sensory profiles, contrasting with those produced using acrylic and stainless steel. These sensory findings emphasize the impact of the Koar® filter holder material on the coffee beverage's sensory attributes and underscore the importance of understanding the specific perceptions and needs of the target audience. Practical applications: Considering the importance of the studies with consumers, this research presents findings that are very important for industries in the equipment production segment for the coffee beverage extraction process. Based on the results presented in this study, industries can develop products with specific materials that can enhance the sensorial attributes of the coffee beverage according to consumer preference. [ABSTRACT FROM AUTHOR]

In present work, the novel Al2O3-C ceramic filter fabricated by using microporous corundum-spinel powder instead of dense Al2O3 powder and reinforced by SiC whiskers is proposed. The effects of Si powder content (0, 3, 6, and 9 wt. %) on the microstructures and mechanical properties of the filters were studied. After replacing the α-Al2O3 micro-powder with microporous corundum-spinel powder, the in situ spinel whiskers were formed inside the filter skeleton under the reducing atmosphere. The rough surface structure of the microporous powder increased the interface contact area with the small-sized carbon particles, resulting in a compact interface bonding in the filter skeleton and a higher cold compressive strength of the filter. When the Si powder content increased to 6-9 wt. %, the in-situ SiC whiskers were formed not only between the microporous powder, but also inside the pores near the surface of it by vapor-solid reaction mechanism in the filter skeleton. The SiC whiskers synergized with the microporous powder to form a more compact interface structure, thus remarkably enhancing their cold compressive strength and thermal shock resistance. Overall, the mechanical properties of the filters were significantly improved by the addition of 9 wt. % Si powder. The filter skeleton had an apparent porosity of 36.2% and a bulk density of 1.93 g/cm³. The filter also exhibited a high cold compressive strength of 1.59 MPa and a superior thermal shock resistance. It has the potential for better purification efficiency on molten steel in the future due to a rougher skeleton surface structure compared to existing Al2O3-C filters. [ABSTRACT FROM AUTHOR]

Tunable filters are vital not only for dynamic display but also in the miniaturized spectral imaging system. Yet, the present tunable devices possess low optical throughput, bulky volume, slow response, or complex configuration. In this paper, the study proposed and experimentally demonstrated a compact tunable filter module based on metagratings combined with liquid crystals (LC). By the synergetic effect between the birefringent LC and the dichroic metagratings, the module possesses distinct transmissive features by electrically tuning the LC material, resulting from the polarization interference effect. A simple nanoimprinting method, which is suitable for the mass production of nanostructures is adopted for low‐cost fabrication. These unique features endow the present tunable filter module with low cost, high optical throughput, and compact volume. As a proof of concept, a multispectral imager is built with this filter based on a commercial microscope. Experimental results show the system response is five times higher in optical throughput across the whole visible region than the traditional liquid crystal tunable filter and the signal‐to‐noise ratio can be improved by 7 dB. Considering the feasibility of nanoimprinting, this module paves the way for spectral imaging in low‐light conditions and on‐site scenarios such as tongue diagnosis and food quality inspection. [ABSTRACT FROM AUTHOR]

Refractories have a significant impact on the cleanliness of molten steel, especially when utilized as ceramic filters. To explore the feasibility of applying rare‐earth oxides in ceramic filters, the interactions between CeO2/CeAlO3 functional refractories and steels with different Al contents are explored, and compared with the microporous magnesia refractory. In the test of CeO2 refractory, the total oxygen (T.O) content significantly increases, while the dissolved Al content obviously decreases in 38CrMoAl steel (0.876 wt% [Al]). Furthermore, the T.O contents in 38CrMoAl and X70 steel (0.040 wt% [Al]) in the test of CeAlO3 refractory are 22.9% and 70.9% of that in the test of microporous magnesia refractory, respectively. Meanwhile, the loss of dissolved Al in steel caused by the interaction between CeAlO3 refractory and steel is relatively small. Therefore, CeAlO3 is relatively stable after contact with molten steel and promising to be applicated in the ceramic filter for improving the cleanliness of molten steel. [ABSTRACT FROM AUTHOR]

Swine confinement buildings represent workplaces with high biological air pollution. It is suspected that individual components of inhalable air are causatives of chronic respiratory disease that are regularly detected among workers. In order to understand the relationship between exposure and stress, it is necessary to study the components of bioaerosols in more detail. For this purpose, bioaerosols from pig barns were collected on quartz filters and analysed via a combinatorial approach of 16S rRNA amplicon sequencing and metaproteomics. The study reveals the presence of peptides from pigs, their feed and microorganisms. The proportion of fungal peptides detected is considered to be underrepresented compared to bacterial peptides. In addition, the metaproteomic workflow enabled functional predictions about the discovered peptides. Housekeeping proteins were found in particular, but also evidence for the presence of bacterial virulence factors (e.g., serralysin‐like metalloprotease) as well as plant (e.g., chitinase) and fungal allergens (e.g., alt a10). Metaproteomic analyses can thus be used to identify factors that may be relevant to the health of pig farmers. Accordingly, such studies could be used in the future to assess the adverse health potential of an occupationally relevant bioaerosol and help consider defined protective strategies for workers. [ABSTRACT FROM AUTHOR]

The ceramic filter amended with iron (Fe) has proven to be a potential low‐cost method for arsenic (As) removal from groundwater. The presence of Fe, phosphate (P), and silicate (Si) significantly affects the As removal efficiency of the ceramic filter, which has not been passably investigated. The present research aimed to examine the effect of Fe, P, and (or) Si presence as single or in combination on As (III) removal from synthetics groundwater by a low‐cost iron amended ceramic filter (IACF). Laboratory‐scale filtration experiments at different compositions of Fe, P, Si, and As (III) were conducted by the IACF fabricated with a ceramic candle and iron netting box. Fe (II) in synthetic groundwater positively impacted As (III) removal. At a concentration of 2 mg/L of Fe (II), the As levels in the effluent decreased to less than the maximum contamination level (MCL) of 50 μg/L. Groundwater P concentration needed less than 3 mg/L or Si concentrations required less than 35 mg/L to effectively reduce As (III) to below the MCL at 5 mg/L of groundwater Fe (II). The cumulative effect of P and Si on As removal was found to be more significant than distinct contributions. The presence of 2 mg/L P and 35 mg/L or higher Si in the groundwater cumulatively reduced the As removal performance from 92% to 63%, and the MCL was not met. The negative impact of P and Si on As (III) removal followed the order of (P + Si) > P > Si. P competed with As for adsorption sites during the process, while Si inhibited the Fe release and floc formation, significantly reducing As removal performance. The study findings can potentially contribute to optimizing IACF as a low‐cost method for As removal from groundwater. [ABSTRACT FROM AUTHOR]

Producing drinking water from polluted water is expensive; thus, the fabrication of environmentally‐friendly and cost‐effective materials to treat polluted water is vital. A strategy involving the exploitation of waste resources to mitigate their impact on the environment has attracted special attention. This strategy is achievable by, among other things, developing materials including ceramic filters. In this study, natural clay, and macadamia nutshell powder were used to fabricate ceramic filters to remove methyl orange (MO), chromium (Cr), and lead (Pb) from aqueous solutions. The physicochemical characteristics of the fabricated filters were carried out and their ability to remove the pollutants was investigated. The filter with 20 wt% macadamia nutshell powder (M2) removed 92 %, 62 %, and 29 % of MO, Pb (II), and Cr (III), respectively. This was attributable to the high porosity of the filter as demonstrated by Brunauer‐Emmett‐Teller analysis. Furthermore, there was an increase on the removal of Cr (29.71 % to 84.5 %) in the presence of other competing co‐metals, however, a drop in Pb removed was observed (62.99 % to 38.67 %). Turbidity removal of up to 97.2 % was achieved using the M2 filter. The reported filter fabrication approach is facile, easy to replicate without special training, and environmentally friendly. [ABSTRACT FROM AUTHOR]

Biomass burning is a significant anthropogenic source of air pollution, including the preharvest burning of sugar cane. These burn events result in atmospheric emissions, including semivolatile organic compounds, that may have adverse impacts on air quality and human health on a local, regional, and even a global scale. Gaseous and particulate polycyclic aromatic hydrocarbon (PAH) emissions from various sugar cane burn events in the province of Kwa‐Zulu Natal in South Africa were simultaneously sampled using a portable denuder sampling technology, consisting of a quartz fiber filter sandwiched between two polydimethylsiloxane multichannel traps. Total gas and particle phase PAH concentrations ranged from 0.05 to 9.85 µg m–3 per individual burn event, and nine PAHs were quantified. Over 85% of all PAHs were found to exist in the gas phase, with smaller two‐ and three‐ring PAHs, primarily naphthalene, 1‐methyl naphthalene, and acenaphthylene, being the most dominant and causing the majority of variance between the burn sites. The PAH profiles differed between the different burn events at different sites, emphasizing the significant influence that the crop variety, prevailing weather conditions, and geographical location has on the type and number of pollutants emitted. The potential carcinogenicity of the PAH exposure was estimated based on toxic equivalency factors that showed varying risk potentials per burn event, with the highest value of 5.97 ng m–3. Environ Toxicol Chem 2023;42:778–792. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

The goal of this paper is to investigate a complex validation, developed by Rauschert in Poland, of casted ceramic filters for microfiltration. For disc manufacturing, a self‐developed material RaFo‐MF‐401e with a filtration membrane was used. The presented experiment was conducted on component, subsystem, and system levels. Component level analysis consisted of the investigation of mechanical strength, hardness, rough lifetime, and resistance against acids and alkalis. Annealing at high temperature and humidity was used to test the subsystem. The final system test was executed on the real filtration system. The final aim of the tests was to verify the filtration efficiency of a complete module (core and membrane) in a real filtration device. The filtration quality of the whole setup was very good and the particles in the permeate (filtrated solution) were smaller than 10 μm (defined as D99). Thus, the developed discs provide the expected filtration quality in the range of microfiltration. [ABSTRACT FROM AUTHOR]

Three‐dimensional electron diffraction (3D ED) has become an effective technique to determine the structures of submicrometre‐ (nanometre‐)sized crystals. In this work, energy‐filtered 3D ED was implemented using a post‐column energy filter in both STEM mode and TEM mode [(S)TEM denoting (scanning) transmission electron microscope]. The setups for performing energy‐filtered 3D ED on a Gatan imaging filter are described. The technique and protocol improve the accessibility of energy‐filtered 3D ED post‐column energy filters, which are available in many TEM laboratories. In addition, a crystal tracking method in STEM mode using high‐angle annular dark‐field imaging is proposed. This method enables the user to monitor the crystal position while collecting 3D ED data at the same time, allowing a larger tilt range without foregoing any diffraction frames or imposing extra electron dose. In order to compare the differences between energy‐filtered and unfiltered 3D ED data sets, three well known crystallized inorganic samples have been studied in detail. For these samples, the final R1 values improved by 10–30% for the energy‐filtered data sets compared with the unfiltered data sets, and the structures became more chemically reasonable. Possible reasons for improvement are also discussed. [ABSTRACT FROM AUTHOR]

Porous Si3N4 ceramics were prepared by gel casting combined with a reaction bonding route using monodispersed PMMA as the pore former, and Isobam was used as a gel agent. With the PMMA addition varying from 0 to 20 wt.%, the bending strength was degraded from 94.0 to 39.1 MPa owing to the increased porosity and decreased bulk density. The β‐Si3N4 prismatic grains and round pores introduced by the monodispersed PMMA micro balls would endow the samples with high strength, and the permeability of the resulting samples was increased obviously with the increase of PMMA addition. Flue gas filtration test exhibited that the filtration efficiency of the porous ceramics filter was not degraded with introducing of the PMMA pore former, even though the permeability was increased obviously. The block type of the sample with 20‐wt.% PMMA additions during filtration was cake filtration, which indicates that the sample has the characteristic of being reusable after back‐blowing in flue gas filtration applications. Porous Si3N4 with high strength and permeability fabricated via the reaction bonding route exhibits great potential for low‐cost high‐performance ceramics filters. [ABSTRACT FROM AUTHOR]

Herein, by using 3D printing technology and data‐driven surrogate model‐assisted optimization method, design of a ceramic material‐based nonuniform nonplanar microstrip filter is taken into the consideration in a computationally efficient and low‐cost manner. For this aim, 3D EM model of the proposed design had been used for generating training and validation data sets. Then commonly used state‐of‐the‐art regression algorithms had been used for creating accurate and fast surrogate models to create a mapping between inputs of the model and outputs of the unit element design. After that, Grey Wolf Optimization algorithm had been used for design optimization of a bandpass filter. Then, via the use of 3D printer, the optimally designed filter had been prototyped and its performance characteristics are measured. As a result, by using 3D printer technology, ceramic material, and the proposed method, design optimization of nonuniform nonplanar microstrip filter can be achieved in a computationally efficient way. [ABSTRACT FROM AUTHOR]

Colloidal quantum wells (CQWs) are excellent candidates for lighting and display applications owing to their narrow emission linewidths (<30 nm). However, realizing their efficient and stable light‐emitting solids remains a challenge. To address this problem, stable, efficient solids of CQWs incorporated into crystal matrices are shown. Green‐emitting CdSe/CdS core/crown and red‐emitting CdSe/CdS core/shell CQWs wrapped into these crystal solids are employed as proof‐of‐concept demonstrations of light‐emitting diode (LED) integration targeting a wide color span in display backlighting. The quantum yield of the green‐ and red‐emitting CQW‐containing solids of sucrose reach ≈20% and ≈55%, respectively, while emission linewidths and peak wavelengths remain almost unaltered. Furthermore, sucrose matrix preserves ≈70% and ≈45% of the initial emission intensity of the green‐ and red‐emitting CQWs after >60 h, respectively, which is ≈4× and ≈2× better than the drop‐casted CQW films and reference (KCl) host. Color‐converting LEDs of these green‐ and red‐emitting CQWs in sucrose possess luminous efficiencies 122 and 189 lm W−1elect, respectively. With the liquid crystal display filters, this becomes 39 and 86 lm W−1elect, respectively, providing with a color gamut 25% broader than the National Television Standards Committee standard. These results prove that CQW solids enable efficient and stable color converters for display and lighting applications. [ABSTRACT FROM AUTHOR]

The Hyperspectral Imaging System can obtain the spectral response value of each pixel in a fabric sample image while being applied to fabric color measurement. Compared with the common grating Hyperspectral Imaging System, the Hyperspectral Imaging System based on Liquid Crystal Tunable Filter (LCTF) has the advantages of small size, high spatial resolution, and easy integration, which has potential application prospects in textile industry. In this article, the performance of the LCTF Hyperspectral Imaging System for fabric color measurement was evaluated, and an improved model for calibrating the consistency between it and Datacolor 650 was proposed. First, the 210 Pantone cotton color cards were used as samples to study the color repeatability and reproducibility of the LCTF Hyperspectral Imaging System. For evaluation its color measurement ability, the measured reflectance values were converted to the CIELAB color space and compared with those of Datacolor 650. Then, a Radial Basis Function neural network model was proposed to calibrate the color consistency between LCTF Hyperspectral Imaging System and Datacolor 650 which can fully use the reflectance information of the whole band instead of only adjacent wavelengths. Experimental results show that the LCTF Hyperspectral Imaging System can accurately measure the fabric color with good repeatability and reproducibility, and the consistency between the two instruments was significantly improved based on the Radial Basis Function neural network model compared with the R model. [ABSTRACT FROM AUTHOR]

Herein, the combined influence of reactive cleaning and active filtration on inclusion removal is investigated using numerical simulations. Carbon‐bonded ceramic foam filters with active and reactive effect are inserted into the steel melt to remove nonmetallic inclusions. In case of reactive cleaning, carbon can dissolve from the filters into the melt. As a result, carbon reacts with oxygen on inclusion surface to form carbon monoxide bubbles. The filters can capture inclusions in terms of its active effect. A numerical model is developed in the open source library OpenFOAM to study the efficiency of the combined effect of filters. The results of the numerical simulations show that the flow field and the concentration of carbon are affected considerably by the position and the number of the used filters. Moreover, the results highlight the significant positive effect of reactive cleaning on the level of melt cleanliness despite the short time of the reactive phase of the filters. Moreover, it is apparent from the results that reactive cleaning dominates active filtration. The findings of the article prove the importance of reactive cleaning in the steel casting industry to enhance inclusion removal and improve steel quality. [ABSTRACT FROM AUTHOR]

In this study, the bandpass filter characteristics in standing wave resonator formed in a two‐dimensional (2D) photonic crystal (PC) is integrated with microelectromechanical systems (MEMS) actuator to tune degenerate mode split. A single and sequentially connected indirect coupling structure consisting of waveguide as well as cavity is placed to the 2D PC. It has been shown that the modes of the bands can be split by structural deformation of the PC via MEMS actuator. The modes frequencies can be changed with the bias voltage applied to MEMS structure, which allows to tune about 1 THz (λ = 35 nm). The designed PC and MEMS structures are analyzed with simulation programs using finite difference time domain method and finite element method, respectively. The proposed PC structures can be effectively used in new generation all optical THz communication applications. [ABSTRACT FROM AUTHOR]

While effective defluoridation methods have been developed, most of them are expensive and difficult to apply at a household level. One safe, low‐cost, decentralized water treatment method which is attracting research attention is the use of ceramic filters (CFs). Few studies have explored the use of biochar composites in CFs for defluoridation of water, with the bulk of them being based on batch and column experiments. The aim of this work was to develop, and evaluate a laboratory‐scale, low‐cost CF using clay, sawdust, and iron oxide‐biochar (FBC) for fluoride removal in synthetic and real water samples. Three CFs were fabricated with varying FBC content (0%, 5%, and 10%). Water absorption, apparent porosity, and flow rate decreased with decreasing FBC content, while the impact strength increased with decreasing FBC content. The CFs reduced the fluoride concentration of both the ground water, and synthetic water to below the WHO recommended limit (1.5 mg/L). While further studies are required to optimize the CF, the results demonstrate that a CF decorated with FBC composites is effective for defluoridation of drinking water. [ABSTRACT FROM AUTHOR]

This letter introduces two continuously tunable bandpass filters with substrate integrated coaxial line (SICL) and liquid crystal (LC) technologies. The tunability of the filters is a kind of electric tuning, achieved by the permittivity changing of the LC material filled in the SICL cavities. The SICL resonator and the electric and magnetic coupling between the resonators are investigated. Then, fourth‐order direct‐coupled and cross‐coupled tunable filters (Filter I and II) with center frequency of 6.5 GHz are designed, fabricated, and measured. The experimental results show that the continuous tuning ranges are 220 and 280 MHz for Filter I and II, respectively. Furthermore, the insertion losses of the Filter I and II are 3.93–4.78 dB and 3.65–4.3 dB over the whole tuning range. [ABSTRACT FROM AUTHOR]

Oxide‐bonded porous SiC ceramic filter supports were prepared using SiC powder (d50 = 212 µm), Al2O3, and clay as bond forming additives and graphite as pore former following reaction bonding of powder compacts at 1400°C in air. Reaction bonding characteristics, phase composition, porosity, pore size, mechanical strength, and microstructure of porous SiC ceramic supports were investigated. Mullite bond phase formation kinetics was studied following the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model using non‐isothermal differential thermal analysis (DTA) data. Compared to porous SiC ceramic filter supports having no needle‐like mullite bond phase, materials processed by the mullite bonding technique exhibited higher average strength (22.1%) and elastic modulus (5.4%) at a similar porosity level of ~38%, with upper and lower bounds of their strength, modulus, and porosity being 39.1 MPa, 40.2 GPa, and 36.3% and 34.2 MPa, 31.3 GPa, and 33.0%, respectively. Spray coating method was applied for preparation of oxidation‐bonded SiC filtration layer having thickness of ~150 µm and pore size of ~5–20 µm over the porous SiC support compacts using aqueous slurry made of fine SiC powder (d50 = 15 µm) followed by sintering. The layered ceramics thus prepared are potential materials for gas filter applications. [ABSTRACT FROM AUTHOR]

Clean water is expensive to obtain, hence the need for cheaper and effective ways of treating water. This study investigated the preparation and application/performance of affordable and effective ceramic/silver nanocomposites in the purification of water. Ceramic filters were manufactured by combining clay, flour, and broken clay pots on a weight basis. The dry mix was combined with deionized water, molded, fired, and treated with either silver nanoparticles or silver nitrate solution. Both treatments were done by submerging disks in their respective solutions. Analysis of treated water has shown that the pH of raw water was reduced by 1.08% with clay only filter, 5.20% with silver nitrate/clay filter, and finally 12% with silver nanoparticle/clay composite. Hardness decreased by 67% with nanoparticle composite while water from clay had 0.08% decrease in hardness. Biological oxygen demand fell by 50% with the clay only filter while there was 100% decrease with clay/silver composites. Nitrates decreased with clay only filters by 21.5% but increased in water treated with silver nitrate composite (84%) and clay/silver nanoparticle composite (73%). Inductively coupled plasma spectroscopy was used to estimate silver leaching from disks embedded with silver nitrate (0.024 ± 0.002mg/L) and silver nanoparticles (0.013 ± 0.002 mg/L) using 0.001 M dosage. All parameters investigated were dose‐dependent. [ABSTRACT FROM AUTHOR]

Reference introduction in thermal desorption with gas chromatography is a critical aspect. It is mostly performed by offline liquid calibration using a micro syringe to inject a liquid standard solution on the sorbent in the thermal desorption tube. This is based on the assumptions that the adsorption‐desorption process is quantitative and that no sample is lost in manipulating the tube. However, for analytical procedures involving thermal extraction of solid matrices, the adsorption‐desorption processes for sample and reference differ and the assumptions are not always fulfilled. This is explored in this work. First, issues related to the online liquid calibration were investigated. With tubes containing only quartz filters, a relative loss of over 80% was noticed for some solvents due to tube manipulation processes. Enclosing a bed of mesoporous silica as sorbent limited the losses to about 25% when samples were immediately analysed, and even better results were obtained when tubes were stored for several hours so that proper adsorption could take place. An additional sweep gas during loading boosted the transfer of analytes with recoveries above 95%. Next, an inline injection system was installed on the thermal desorber instrument. This sorbent free, independent calibration tool avoids the drawbacks of other approaches. [ABSTRACT FROM AUTHOR]

Stand‐off Raman spectroscopy offers a highly selective technique to probe unknown substances from a safe distance. Often, it is necessary to scan large areas of interest. This can be done by pointwise imaging (PI), that is, spectra are sequentially acquired from an array of points over the region of interest (point‐by‐point mapping). Alternatively, in this paper a direct hyperspectral Raman imager is presented, where a defocused laser beam illuminates a wide area of the sample and the Raman scattered light is collected from the whole field of view (FOV) at once as a spectral snapshot filtered by a liquid crystal tunable filter to select a specific Raman shift. Both techniques are compared in terms of achievable FOV, spectral resolution, signal‐to‐noise performance, and time consumption during a measurement at stand‐off distance of 15 m. The HSRI showed superior spectral resolution and signal‐to‐noise ratio, while more than doubling the FOV of the PI at laser power densities reduced by a factor of 277 at the target. Further, the output hyperspectral image data cube can be processed with state of the art chemometric algorithms like vertex component analysis in order to get a simple deterministic false color image showing the chemical composition of the target. This is shown for an artificial polymer sample, measured at a distance of 15 m. [ABSTRACT FROM AUTHOR]

Hard X‐ray free‐electron lasers (XFELs) generate intense coherent X‐ray beams by passing electrons through undulators, i.e. very long periodic magnet structures, which extend over hundreds of meters. The SASE1 and SASE2 undulator systems of the European XFEL consist of 35 segments with variable‐gap planar undulators which are initially tuned to precise on‐axis magnetic field strengths in a magnetic measurement laboratory to keep an important quality parameter – the K‐value variation from segment to segment – below a certain limit (3 × 10−4 for 12 keV photon energy). After tunnel installation only photon‐based methods can determine the K‐values of undulator segments with a similar accuracy. The synchrotron radiation from a single or a few segments can be spectrally filtered by a dedicated crystal monochromator (K‐monochromator) and recorded with a photodiode or with an imager that provides 2D information, tuned for high sensitivity to detect low photon densities from distant single undulator segments. This instrumentation is applied for electron orbit analysis and optimization, and adjustment of individual undulators in terms of their central magnetic axis with respect to the electron beam. Single undulator segments were analysed by scanning the monochromator crystal angle and detecting the steepest slope of a photodiode signal. Alternatively, in the imaging method, an imager recorded the radiation cone of electrons passing through the undulator segment. From the spatial distribution of the radiation, the K‐parameter was determined with a sufficiently high relative accuracy. [ABSTRACT FROM AUTHOR]

Rationale: The chemical composition of the particulate phase of cigarette smoke inhaled by the active smoker is still poorly known in spite of its importance from a health point of view. A non‐targeted approach is applied to cigarette smoke particles collected on a quartz filter to obtain an as complete as possible description of this complex mixture. Methods: A home‐made smoking machine including devices for volatile organic compounds (VOCs) and particle sampling was used. The validation of the cigarette smoking and cigarette smoke collection procedures was conducted by the quantification of some compounds by gas chromatography/mass spectrometry (GC/MS). The particles were investigated by Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS) directly after their collection on quartz filters by laser/desorption ionization (LDI) or after extraction with CH2Cl2 by electrospray ionization (ESI). Results: The determination of the benzene, toluene, ethylbenzene and xylenes (from 2 to 35 μg/cigarette) and nicotine (0.68 ± 0.05 mg/cigarette) validated the used sampling method. The complementarity of the LDI and ESI sources for the cigarette smoke analysis was established. The ESI analyses evidenced polar compounds and components with a pyridine group and LDI ensured the detection of poly‐condensed heteroaromatic species. Finally, this methodology was employed to characterize particles from cigarettes with or without flavoring additives. Conclusions: Some insights into the composition of cigarette smoke inhaled by active smokers have been obtained. The ~1750 observed features revealed the huge complexity of cigarette smoke particles and the diversity of the possible associated health issues. Both heteroaromatic and highly oxygenated compounds produced by combustion and pyrolysis have been highlighted. [ABSTRACT FROM AUTHOR]

Rationale: Secondary organic aerosols (SOAs) represent a significant portion of total atmospheric aerosols. They are generated by the oxidation of volatile organic compounds (VOCs), and particularly biogenic VOCs (BVOCs). The analysis of such samples is usually performed by targeted methods that often require time‐consuming preparation steps that can induce loss of compounds and/or sample contaminations. Methods: Recently, untargeted methods using high‐resolution mass spectrometry (HRMS) have been successfully employed for a broad characterization of chemicals in SOAs. Herein we propose a new application of the direct analysis in real time (DART) ionization method combined with HRMS to quickly detect several hundred chemicals in SOAs collected on a quartz filter without sample preparation or separation techniques. Results: The reproducibility of measurements was good, with several hundred elemental compositions common to three different replicates. The relative standard deviations of the intensities of the chemical families ranged from 6% to 35%, with sufficient sensitivity to allow the unambiguous detection of 4 ng/mm2 of pinic acid. The presence of oligomers and specific tracers was highlighted by MSn (n ≤ 4) experiments, an achievement that is difficult to attain with other ultrahigh‐resolution mass spectrometers. Contributions of this untargeted DART‐HRMS method were illustrated by the analysis of fresh and aged SOAs from different gaseous precursors such as limonene, a β‐pinene/limonene mixture or scots pines emissions. Conclusions: The results show that it is possible to use DART‐HRMS for the identification of tracers of specific aging reactions, or for the identification of aerosols from specific biogenic precursors. [ABSTRACT FROM AUTHOR]

In this study, a compact filtering 2 × 2 array antenna with high selectivity utilizing substrate integrated waveguide (SIW) is presented. The proposed antenna structure is mainly composed of coplanar waveguide feeding structures, SIW filtering cavities, and four radiation patches by low‐temperature co‐fired ceramic technology. The designed antenna not only achieves the advantages of high selectivity but also realizes a miniaturized volume of 12 × 12 × 1.18 mm3. The simulated and measured results show that the filtering antenna achieves a center frequency of 28 GHz and has a 10.7% fractional bandwidth with a 10.8 dB antenna gain. [ABSTRACT FROM AUTHOR]

Laue micro-diffraction and simultaneous rainbow-filtered micro-diffraction were used to measure accurately the full strain tensor and the lattice orientation distribution at the sub-micrometre scale in highly strained, suspended Ge micro-devices. A numerical approach to obtain the full strain tensor from the deviatoric strain measurement alone is also demonstrated and used for faster full strain mapping. The measurements were performed in a series of micro-devices under either uniaxial or biaxial stress and an excellent agreement with numerical simulations was found. This shows the superior potential of Laue micro-diffraction for the investigation of highly strained micro-devices. [ABSTRACT FROM AUTHOR]

The performance of a low cost and simple ceramic filter to a membrane bioreactor (MBR) process was evaluated for greywater treatment. The ceramic filter was submerged in an acrylic cylindrical column bioreactor. Synthetic greywater (prepared by shampoo, dish cleaner and laundry detergent) was fed continuously into the reactor. The filter effluent was obtained by gravitational pressure. The average flux performance was observed to be 11.5 LMH with an average hydraulic retention time of 1.7 days. Complete biodégradation of surfactant (methylene blue active substance removal: 99-100%) as well as high organic removal performance (biochemical oxygen demand: 97- 100% and total organic carbon: >88%) was obtained. The consistency of flux (11.5 LMH) indicated that the filter can be operated for a long time without fouling. The application of this simple ceramic filter would make MBR technology cost-effective in developing countries for greywater reclamation and reuse. [ABSTRACT FROM AUTHOR]

A miniaturised spherical resonator based X‐band dual‐mode bandpass filter that is 3D printed using a ceramic filled photosensitive resin is the first time presented. This filter has substantially enhanced thermal handling capability than its counterparts that are printed out of the conventional resins with a relatively low working temperature. The filter's thermal handling capability is experimentally characterised by measuring its RF performance under different working temperatures using a pair of tailor made aluminium thermal isolators to separate the network analyser from the heat source. The measured results demonstrate that the ceramic resin based filter is capable of operating at much higher temperatures, and has a much better thermal stability than the one made of ordinary resin, without losing its intrinsic light‐weight advantage over the one made of metal. This type of thermally‐stable ceramic filled resin can be widely applied to stereolithography‐based 3D printed lightweight microwave and millimetre‐wave waveguide devices. [ABSTRACT FROM AUTHOR]

We present numerical simulation of particle filled resin flow through a fibrous medium taking into account dual scale porosity in LCM (Liquid Composite Molding) processes. During the flow, a strong interaction between the particle motion and the fluid flow takes place at the porous medium wall or at the fiber bundle surface. A model is developed to describe the particle deposition and filtering in the porous medium. In this study, the Stokes-Darcy equation is solved to describe the resin flow in a mesoscopic scale. The particle deposition mechanism is extensively studied taking into account the influences from such parameters as porous medium permeability, particle size and pressure drop. The mechanism leading to the accelerated or delayed filling is treated by analyzing the velocity filed around the fiber bundle surface. Finally, particle filtering simulation is performed for different particle loading levels to demonstrate the particle deposition and filtering mechanism during the composites manufacturing by LCM processes where the resin mixed with particles is injected into a fiber preform with dual scale porosity. [ABSTRACT FROM AUTHOR]

Reticulated silicon carbide ( Si C) ceramic filters are prepared with modified coatings in an attempt to improve mechanical properties of the sintered filter. Two classes of coatings are used: mixtures of non- Si C ceramic and sintering aid and mixtures of Si C and glass. Various candidate ceramics, sintering aids, and glasses are screened. The most promising coatings are determined to be silica with 5 wt% bismuth oxide and Si C with ≤10 wt% Spruce Pine Batch glass. Filters with these coatings are prepared and subjected to mechanical abuse. Both coatings improve the ruggedness of the filter relative to the standard uncoated Si C type. Filters with <10 wt% glass additive were subjected to molten metal impingement and filtration of liquid gray iron at 1510°C. Those with 5 wt% glass or more softened during filtration. Those with 2.5 wt% glass or less survived without failure. [ABSTRACT FROM AUTHOR]

This Letter reports a high‐performance film bulk acoustic resonator (FBAR) that can be applied in 5G wireless communication. The FBAR has a back‐etched free‐standing structure using an ultra‐thin single‐crystalline lithium niobate (LiNbO3) as the piezoelectric film. The thin LiNbO3 was obtained by the smart cut method and FBARs were fabricated by a standard MEMS process. Owing to the superior bulk‐like properties of the single‐crystal thin film, the fabricated FBARs have a resonant frequency of 5.0 GHz, a quality factor above 1800 and an electromechanical coupling coefficient of 2.66%, demonstrating a promising potential of FBAR filters in 5G and future 6G applications. [ABSTRACT FROM AUTHOR]

The (1- x- y)K0.5Na0.5NbO3- xCaZrO3- yLiNbO3 (KNLNCZ- x- y) lead-free piezoelectric ceramics were fabricated by conventional technique, and the effect of the addition of CaZrO3 and LiNbO3 on the phase transitions and piezoelectric properties of the KNN-based ceramics was investigated. The addition of CaZrO3 will shift the orthorhombic-rhombohedral transition temperature of the ceramics to above room temperature, and with the increase of the CaZrO3 additives, a dielectric peak rises up near the orthorhombic-tetragonal phase transition of the ceramics resulting in the spread of the ferroelectric-paraelectric phase transition over a rather wide temperature range due to polar nanoregions arising from composition fluctuation. For x = 0.05, the addition of LiNbO3 is effective to shift the TR-O and TO-T downward and TC upward in KNLNCZ-0.05- y ceramics. Optimum piezoelectric properties ( d33 = 216 pC/N and kp = 42.9%) were obtained for the KNLNCZ- x- y ceramics with x = 0.05 and y = 0.07 due to the decrease of TO-T to be around room temperature. [ABSTRACT FROM AUTHOR]

A special finite-difference time-domain (FDTD) formulation which allows electromagnetic (EM) wave wideband simulations of oblique incidence for periodic media is used for the design and analysis of an infrared photonic crystal filter with dual stopbands at 3–5 and 8–12 μm. The transmission coefficient in the main stopband (8–12 μm) is below -10 dB. Scattering coefficients are calculated for different incidence angles, and the stopbands are shown to exist for different angles of incidence. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 81–87, 2000. [ABSTRACT FROM AUTHOR]

For a conventional MF-band piezoelectric filter, the contour vibration has mainly been used in which the whole of the vibrator body vibrates, and the vibrator is supported at its nodal point by a spring or a soldered wire. This disgrades the characteristics of the filters, widens their manufacturing deviations, and limits their reliability and miniaturization. This paper proposes a new type of piezoelectric ceramic filter for the MF-band using the edge-mode vibration. This type of filter has a sample shape and a small size, and can be supported by vibration-adsorptive means such as a trapped-energy type vibrator. The three-terminal single-mode filter is presented in which the electrode us divided with a gap into two parts to be used for the input and output. The relationship between the width of the gap and the fractional bandwidth of the filter is calculated theoretically, and the upper limit of its bandwidth is given. By using Pb (Zr, Ti)O3 piezoelectric ceramics, two types of 455-kHz filters having the 3-dB fractional bandwidth of 1.3% and 1.6%, respectively, have been produced experimentally. By connecting 3 or 4 units of other type of the filters in cascade, a filter having the out-of-band attenuation greater than 50 dB over the wide frequency range up to ten times the center frequency has been produced successfully. To widen the bandwidth of the edge-mode piezoelectric filter, the double-mode filter consisting of two acoustically coupled resonators is also proposed. Experimental results confirm the practical usefulness of this type of filter. [ABSTRACT FROM AUTHOR]

The energy trapping of the higher-harmonic width-extensional and width-shear vibrations in a piezoelectric ceramic strip is studied based on the dispersion characteristics of these modes. By the use of energy trapping of the higher-harmonic width vibrations, new small-sized trapped-energy resonators and filters that can be used at the high-frequency range beyond several megahertz are developed. In the resonator and filter using a higher-harmonic width vibration, it is necessary to excite strongly the width vibration of a specific order and to suppress all other vibrations. In this paper, a new electrode configuration is proposed for this purpose by taking into account the stress distribution of the mode. In addition, this method is used for fabrication of 4.5 and 10.7 MHz trapped-energy filters using the 3rd-harmonic width-extensional vibration and the trapped-energy resonators using the 2nd, 3rd- and 4th-harmonic width-extensional vibrations. [ABSTRACT FROM AUTHOR]

A novel piezoelectrically adjustable array of mirrors is proposed for large reflector antenna surface distortion compensation. As compared to the conventional approach with variable phase shifters and amplitude feed array, significantly lower rf loss, mass, and cost reflector antennas can be achieved with this innovative approach. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14: 221–224, 1997. [ABSTRACT FROM AUTHOR]

A terahertz (THz) micromachined waveguide bandpass filter based on metallic two‐dimensional (2D) electromagnetic crystal (EMXT) with a square lattice is proposed. The filter structure with three dual‐mode circular cavities and two rectangular waveguides is obtained by removing and optimising the EMXT unit cells in a 15 × 20 cells array. This filter, fed by WR2.2 waveguides, is fabricated with the silicon microelectromechanical systems technique and measured using a vector network analyser (VNA) with an extender. The measured fractional bandwidth is 7.6% with a 426.5 GHz centre frequency. The best insertion loss and return loss are 2 and 24 dB, respectively. These results agree well with the simulations. The proposed THz EMXT filter indicates a novel approach to obtain THz waveguide passive devices and has application potential in THz communication and detection. [ABSTRACT FROM AUTHOR]

Purpose The wavelength dependence of the light scattering is related with the characteristics of the inhomogeneities in the ocular media, and therefore, an objective assessment could be used to the early detection of underlying ocular pathologies. We developed a new optical instrument for measuring light scattered in the human eye at different wavelengths. Methods Using a double‐pass configuration, series of disks of uniform radiance with an increasing angular dimension are sequentially projected on to the retina. As a light source, a white light halogen lamp is spectrally filtered by using a liquid crystal tunable filter, selecting three different wavelengths: 550, 600 and 650 nm (FWHM = ± 50 nm). The disk's retinal images are recorded by a cooled electron‐multiplied CCD camera. The derivative of intensity at the center of each disk's retinal image with respect to its radius provides the eye's wide‐angle double‐pass point‐spread function (PSF). The method was applied in an artificial eye with different levels of induced scattering, and in a group of normal subjects. Results In the artificial eye, the increasing scattering induced is successfully discriminated at the more eccentric angular domain of the wide‐angle PSFs. In the group of subjects, the estimated wide‐angle PSFs differ from the lower to the larger wavelengths. The PSF at 550 nm is characterized by more intense light scatter in the angular range between 5 and 10 degrees, while the PSF at the 650nm showed a relatively increased scattered light between 0 and 2 degrees. This would be related to the deeper interaction of th Conclusion An optical objective method is sensitive enough to detect consistently differences in light scatter for different wavelengths. [ABSTRACT FROM AUTHOR]