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• Introduced parallel-flow cooling in BESS. • Targeted anisotropic thermal properties in LIBs. • Achieved 11.3 % reduction in peak temperature. • Improved safety and viability with a 75.9 % index boost. As the demand for efficient energy storage solutions intensifies, container-type battery energy storage systems (BESS) have gained prominence. BESS usually utilizes large-format laminated lithium-ion battery (LIB) modules, which inherently possess unique anisotropic thermal properties. Specifically, the surface regions with elevated temperatures exhibit high thermal conductivity, while the cooler zones at both ends manifest reduced conductivity. Such disparities emphasize the challenge of developing an effective battery thermal management system (BTMS) for these modules. To address this, our study introduces an innovative BTMS configuration wherein the batteries are aligned in series, while cooling air flows parallel to them. This parallel-flow cooling approach capitalizes on the anisotropic properties, intensifying airflow over the surfaces and recirculating cooling air to optimize heat dissipation from hotspots. Consequently, our system reduces the peak temperature from 42.3 °C to 37.5 °C, as well as the temperature difference (ΔT) from 14.3 °C to 10.2 °C across the entire BESS, respectively representing 11.3 % and 28.7 % changes. This leads to a substantial 75.9 % enhancement in the performance index, significantly augmenting both the safety and commercial viability of the BESS. [ABSTRACT FROM AUTHOR]

Abstract BiFeO 3 (BFO) samples with nearly perfect ferroelectric hysteresis loops were synthesized from chemical solution via hydrothermal route at 200 °C. However, for many applications, ceramic samples of reasonable bulk density (>80%) have to be sintered at temperature over 700 °C, which in this case results in a significant reduction in resistivity due to increased amounts of Fe2+. Interestingly, doping of a few percent Sb minimized such a problem and the sintered Sb:BFO ceramics retained a similarly high resistivity as samples cold-pressed from the chemical-solution synthesized powders. However, for cold-pressed samples, Sb:BFO actually had higher conductivity than undoped BFO. Temperature-dependent conductivity showed that cold-pressed samples of both undoped and Sb doped BFO had the similar activation energy of 1.0 eV, typical for electrons trapped in oxygen vacancies. After sintering, the activation energy of Sb:BFO remained almost unchanged, but the activation energy of undoped BFO changed to 0.4 eV, which is associated to electron hopping between Fe2+/Fe3+. X-ray photoelectron spectroscopy (XPS) showed a significant increase in Fe2+/Fe3+ ratio from 6.6/93.4 to 25.7/74.3 in undoped BFO after sintering, while for 1% Sb doped BFO the increase was much milder from 10.9/89.1 to 14.1/85.9. XPS also showed that Sb had single +3 oxidation state before sintering, but after sintering a fairly large portion of Sb5+ occurred. So, charge compensation for oxygen vacancies in undoped BFO was achieved dominantly by reduction of Fe3+ to Fe2+, while in Sb:BFO it was achieved more by cation vacancies. Highlights • Pure and Sb-doped BiFeO 3 were synthesized by hydrothermal method at 200 °C. • As-prepared samples showed typical hysteresis loops of ideal ferroelectrics. • Sintering the hydrothermal powders resulted in a great decrease in resistivity. • Sb doping helped to retain a similarly high resistivity in the sintered samples. • Sb doping kept oxygen vacancies rather than Fe2+ ions as the main defects. [ABSTRACT FROM AUTHOR]

New discoveries presented in the last decade for enhancing boiling performance utilizing nanoscale structures on surfaces are critically examined in this paper. Since the mechanism for such a phenomenon is not fully understood, this review mainly focuses on the experimental studies reported in the literature on the boiling phenomena on nanostructures, and implementation of nanostructures on various substrates. The paper also focuses on the interpretation of underlying phenomena for enhancing the boiling performance. The main influencing parameter in controlling is seen as the change in the surface energy of the boiling surface, which is characterized by the contact angle of the liquid and vapor phase interface at the heating surface. The nanostructures are seen to alter the contact angle. Design consideration and theoretical developments are also discussed, followed by practical aspects of nanostructure manufacturing. The issues related to performance, ease of fabrication, and durability (whenever available) are reviewed and recommendations are made for future research in this emerging area. [ABSTRACT FROM AUTHOR]

A bubble-based acoustofluidic filtration (BAF) microfluidic device, which employs cross-flow filtration (CFF) and acoustic streaming, separates cells with high efficiency for forensic analysis. Forensic samples are typically complex and contain a substantial number of squamous epithelial cells from the female vagina, which tend to have fouling problems during filtration due to their morphological and cell adhesion differences. To overcome this issue, the BAF device utilizes bubble oscillation by bulk acoustic wave (BAW) to generate acoustic streaming, which offers additional hydrodynamic forces for side flushing cleaning and achieves effective removal within a mere 0.5 seconds. Our device is tested with imbalanced cell mixtures of sperm and epithelial cells with large disparity ratios. By concurrently employing CFF and acoustic streaming, the samples with our sperm-enrichment can achieve 91.72–97.78% for the recovery rate and 74.58–89.26% for the purity in the sperm enrichment. They are further subjected to short tandem repeat (STR) profiling, enabling the identification of perpetrators. Notably, even samples with minimal sperm cells demonstrated a significant increase in the male donor DNA ratio, while the peak heights of female alleles became virtually undetectable. The exceptional cell separation capability demonstrated by our BAF device highlights its potential applications in forensic sciences and other areas of cell biology. [ABSTRACT FROM AUTHOR]

As digital microfluidics (DMF) becomes a popular approach to automating biochemical reactions for various fields, its applications requiring numerous droplets with high volume consistence in parallel analysis still present a great challenge. DMF conventionally utilizes the three-electrode method to split droplets one by one – it has low throughput and noticeable droplet volume variations. To address this challenge, a novel splitting method with a zigzag row-electrode design on electrowetting-based DMF chips is proposed. The liquid is first stretched on the row-electrode, then split by the electrode array. The row-electrode promotes the meniscus filling phenomena, providing larger overlapping areas, thereby stabilizing the volume of droplets generated. Twenty (20) droplets of 6–8 nL with the volumetric coefficient of variance (CV) at only 1.26% are simultaneously generated, excluding the droplets at both ends. Theoretical analysis is developed and validated by the experiments to realize the relationship of important geometrical parameters. This method can not only rapidly produce multiple daughter droplets with excellent droplet volume consistence, but also preserve the common DMF fabrication and actuation scheme without modification. It shows great promise for the DMF applications that require high-throughput downstream processes. • A droplet-splitting method, featuring zigzag row-electrodes, is proposed on DMF. • The row-electrode promotes the liquid meniscus filling and electrowetting forces. • Twenty (20) droplets with their CV= 1.26% in volume are simultaneously obtained. • Theoretical analysis is conducted and validated by the experiments. [ABSTRACT FROM AUTHOR]

A wearable tactile device, based on the electrical contact resistance (ECR) between the two fabric substrates, is developed in this work for continuous health monitoring. Microscale pillar structures are formed over top and bottom fabric substrates by screen‐printing technique with conductive inks followed by the face‐to‐face assembly of top and bottom parts. The contact areas between the substrates increase after the application of an external force, resulting the increment of charge carrier conduction and reduction in ECR value. To enhance the sensitivity, the device is optimized with two different conductive inks (i.e., silver and graphene inks) to create pillar shaped microstructures resulting a higher sensitivity due to the variation in ECR. This wearable tactile sensor's practical applications also are investigated in monitoring human wrist pulses with wireless module and smartphone, showing its capability in faster response and high sensitivity for internet‐of‐thing and medical applications. [ABSTRACT FROM AUTHOR]

A microfluidic device, which performs a primer extension technique onto microbeads, is demonstrated to genotype Single Nucleotide Polymorphism (SNP) on genomic DNA. The device has on-chip heaters and sensors to create a uniform and yet stable temperature gradient between 56 °C and 94 °C across an array of serpentine microchannels, where the microbeads carry allele-specific primers passing through for thermal cycling. As the primers on the beads is designed to be only extended when perfectly matched with the SNP site of the template, the mismatched samples will not be amplified. The SNP discrimination is achieved. In addition that the microfluidic environment promote enhanced mass transport and better hybridization kinetics, the microbeads offer an advantage for faster thermal response and higher signal-to-noise ratio. Three most-frequent variants in one SNP location from genomic DNA of Taiwan country chicken are successfully distinguished in only five thermal cycles, compared to thirty (30) thermal cycles in traditional approaches. Moreover, the SNP genotyping procedures, which typically involves multiple steps in amplification and detection, were integrated onto a single chip. [ABSTRACT FROM AUTHOR]

DNA extraction is one of the most essential steps in nucleic acid testing, which usually requires a series of reagent mixing, centrifugal separations, and manual operations. While microfluidic devices have shown their capability in point-of-care applications, some of them face the challenge in on-chip sample preparation, such as DNA extraction from blood samples, prior to the diagnosis. Although digital microfluidic (DMF) eliminates the need of complicated fluidic actuation components and draws great attentions as a promising Lab-on-a-Chip platform, its capability in DNA extraction has been limitedly shown. Herein, we develop a protocol on a DMF platform for DNA extraction. As the protocol contains blood, magnetic beads, a variety of liquids, and complicated steps, it was implemented in a sequence of droplet operations with our proposed washing/droplet-separation strategy. Our on-chip extraction protocol was conducted with room-temperature incubations and much less washing cycles. The results were confirmed by using SYBR-Green dye staining and gel electrophoresis. Therefore, the DMF device was shown to permit on-chip DNA extraction with fewer sample/reagent consumption and shorter operation time. [ABSTRACT FROM AUTHOR]

Taylor-Couette devices with a rotating filtration membrane are utilized to separate cellular components and to prepare platelet (thrombocytes, PLT) concentrate from whole blood. Due to the complicated nature of the working fluids (e.g. blood), systematic analysis is conducted to enhance the separation efficiency. Flow visualization and cell extraction techniques are applied to understand the cell distributions and classification in different flow regimes in the devices. Blood cells are found to be classified by Taylor vortices: erythrocytes (red blood cells, RBCs) and leukocytes (white blood cells, WBCs) moved toward the periphery of the vortices, while platelet remained close to the center of the vortices due to different sizes for these blood cells. The blood filtration efficiencies are evaluated using two devices at different radius ratios with a series of Reynolds number and flow rates. Operated at similar Reynolds numbers, the device can have higher filtration throughput by making a smaller inner cylinder, for comparable PLT recovery rates. An approximately 90 % recovery rate for PLT was obtained within 40 % volumetric ratio, while the ones for RBC and WBC were 75 % and 85 % respectively. [ABSTRACT FROM AUTHOR]

An optoelectronic system is presented for online measuring the concentrations of uric acid and β2-microglobulin in dialysates during hemodialysis (HD). The optoelectronic system consists of two sets of ultra-violet (UV) light emitting diodes (LEDs), flow cell, and photodiodes (PD); one set is for absorbance measurement of uric acid at 278 nm, while the other set is for β2-microglobulin measurement at 315 nm. The flow cell is employed for dialysate passing through during HD and for the online absorbance measurement. Further, a cylindrical flow cell is applied to reduce the total internal reflection (TIR) and to abate the stray light radiation on the PD for better linearity and less deviation. The system is first calibrated with standardized solutions and integrated with a commercial HD machine to test and monitor dialysate from 10 HD sessions of six (6) patients in the clinical study. The concentrations of uric acid and β2-microglobulin in dialysate can be obtained using our optoelectronic systems; more they are used to predict the concentrations in the patients' serum using supporting vector machine (SVM) regression. The results displayed very good correlations, R2 = 0.8482 for uric acid and 0.7208 for β2-microglobulin, showing the great potentials of our systems with online HD monitoring capability. • An optoelectronic system is presented to measure the absorbance and online monitor the concentrations of important molecules in dialysates during hemodialysis (HD). • The system, made of UV LEDs and photodiodes, is integrated with a commercial HD machine and tested to real-time measure the concentrations of uric acid and β2-microglobulin in dialysates in clinic trials. • The concentrations of uric acid and β2-microglobulin in patients' serum are determined by the system, with the measurement correlated by using supporting vector machine (SVM) regression. • This online measurement capability of the system can be extended to find the reduction ratio and to assess the adequacy for HD treatment. [ABSTRACT FROM AUTHOR]

A tactile-sensing device, made of biodegradable Polyvinyl alcohol (PVA) material, has been developed. The device has a composite PVA film, with conductive fillers of Iron (Fe) particle or multi-walled carbon nanotube (MWCNT), sandwiched in between top and bottom PVA substrates. The filler allows conducting paths to be formed when the contact areas between the substrates increases with an external applied force, resulting in the reduction of Electrical Contact Resistance (ECR). Our sensors employ a much simpler structure and fabrication method compared to other previously reported biodegradable tactile sensors. The devices are optimized with their filler weight percentage and device structure, showing excellent sensitivity (1.998 kPa − 1) in the subtle pressure range (0~0.5 kPa). These tactile sensors are tested for air flow and vibration detections, showing the potential for future low-cost biodegradable wearable health monitoring applications. [Display omitted] • Feasible device fabrication method which can repeated time to time and suitable for mass production. • Biodegradable substrate and sensing materials have been used for device fabrication. • High sensitivity of 1.998 kPa-1 at 0.5 kPa has been achieved. • Capable of detecting air-flow and vibration at subtle pressure range (0–0.5 kPa). [ABSTRACT FROM AUTHOR]

Macromol. Mater. Eng. 2021, 306, 2100130 https://doi.org/10.1002/mame.202100130 The above article, published online on 17 June 2021 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal's Editor‐in‐Chief, David Huesmann, and Wiley‐VCH GmbH. The retraction has been agreed due to a non‐disclosed previous publication of data in this article that, had the editorial team been made aware of upon submission, would have affected the likelihood of the article being considered further. As a result, the journal has made the decision to retract this article. [ABSTRACT FROM AUTHOR]

Abstract: A novel way to manipulate micro-objects using thermocapillary effect in a liquid droplet is presented for the application in optical scanning micromirror. Thermally induced, the surface tension gradients cause convection flows in a liquid droplet from high-temperature to low-temperature regions, changing the droplet shape. The contact angle hysteresis meanwhile is applied to keep the droplet from rolling away. The micro-object on top is therefore moved along the deformed droplet, which functions as a micromirror rotating around a liquid pivot. The device characterization is conducted and the two degree-of-freedom (2 DOF) scanning capability is demonstrated. [Copyright &y& Elsevier]

Abstract: Doped polypyrrole coatings of varying degrees of wetting characteristics were prepared by a one-step anodic polymerization process and subsequently subjected to external applied potentials in an aqueous sodium benzenedodecylsulfonate solution. When an applied potential was increased from −0.9 to +0.9 at steps of 300mV for 300s at each step, static contact angles gradually increased from 64° to 122°. The surface morphology of as-deposited polypyrrole was observed to transform from being nodular to an increasingly rough surface composed of microscale islands with nanoscale roughness, forming a micro/nanoscale hierarchical structure. The average roughness of these microscale islands were measured to be 2.3nm at −0.8V, which increased to 14.6nm at +0.8V, compared to the average roughness of doped polypyrrole at 4.8nm. These microscale islands were oblong in shape, and their sizes increased as the applied potential increased. Changes in the average roughness resulted in a change in the surface wettability of polypyrrole—as-deposited polypyrrole showed a static contact angle of 90°, however, it lowered to 70° at −0.8V and irreversibly increased to 115° at +0.8V. [Copyright &y& Elsevier]

Front Cover: In article number 2100130 by Yen‐Wen Lu and co‐workers, a fabric tactile sensor, based on the fact that contact resistance between two surfaces changes when pressure is applied, is developed by using a screenprinting technique for subtle pressure sensing (<10 kPa) at high sensitivity. Wrist pulse measurements and spatial pressure mapping using the sensors with wireless modules are demonstrated for wearable health monitoring and internet‐of‐things applications. [ABSTRACT FROM AUTHOR]

B Front Cover b : In article number 2100130 by Yen-Wen Lu and co-workers, a fabric tactile sensor, based on the fact that contact resistance between two surfaces changes when pressure is applied, is developed by using a screenprinting technique for subtle pressure sensing (<10 kPa) at high sensitivity. Wrist pulse measurements and spatial pressure mapping using the sensors with wireless modules are demonstrated for wearable health monitoring and internet-of-things applications. [Extracted from the article]

We report the fabrication of a plasma-generating device on a paper substrate. This device was fabricated using a screen print process. Plasmas were ignited between two parallel electrodes with a plasma gap of 237 to 710 \mu\m using a dc power source. We demonstrated that a stable helium plasma can be sustained when the substrate is flat, rolled, and folded along various orientations. When the plasma was ignited with a 0.2-\mu\L salt solution droplet with 1.4, 4.6, and 7.8 ng of Li, Na, and K respectively applied to the discharge gap, clear metallic emission lines emanated from the plasma. Our result demonstrates that this paper-based plasma device can be used in analytical applications.\hfill[2012-0006] [ABSTRACT FROM AUTHOR]

• A microfluidic device, which creates a defined temperature gradient through feedback control, for on-chip microtubule (MT) polymerization. • The temperature gradient allows asymmetrical MT polymerization, leading unidirectional MT assembly and good alignment within an angular range, in a confined environment. • The MT alignment is quantified by using structure-tensor image processing technique, which gives a more precise determination of the main orientation. • At the similar temperature, the MTs show an alignment within 30° under the temperature gradient field, whereas they are widely dispersed under the uniform temperature field. • MT polymerization and alignment are shown to be controlled across a distance by the temperature gradient and tubulin concentration We propose the utilization of a microfluidic platform, which generates a defined temperature gradient, for on-chip microtubule (MT) polymerization. The temperature gradient allows the MTs to be asymmetrically polymerized in a spatially-restricted, nature-mimicking environment. MTs are unidirectionally assembled and neatly aligned along the temperature gradient direction. To quantify the MT alignment, a structure-tensor-based image processing technique is employed. At the similar temperature, the MTs show an alignment within 30° under the temperature gradient field, whereas they are widely dispersed under the uniform temperature field. Further, the MT polymerization and alignments at two different tubulin concentrations are examined. The MTs polymerized at the higher concentration are aligned for a longer distance than the ones at the lower concentration due to sufficient tubulin concentration. [ABSTRACT FROM AUTHOR]

A response from the authors of the article "MacCallum plaque causes acute myocardial infarction in a young man" in the 2015 issue is presented.