Performance Enhancement of the In-Line Fan Equipped with the Guiding Vane and the Tail Body

This integrated numerical and experimental study intends to enhance the performance of an in-line fan with the implement of the guiding vane and the tail body. At first the flow flied associated with the original in-line fan is simulated and analyzed within the framework of CFD code Fluent, in which the finite volume method is applied. Next, the guiding vane is constructed based on the calculated flow characteristics, and attached in the downstream of rotor to smoothen the flow pattern. An appropriate guiding vane with high-performance and low-noise features can be achieved after several design iterations. In addition, the tail body connected to the motor is introduced for further enhancing the fan performance by reducing the sizes of wake and reversed flow behind the hub. Thereafter, to manufacture the mockup for experimental verification, the modified fan with guiding vane is plotted in the CAD/CAM format for mockup fabrication via the rapid-prototype technique. Moreover, a set of relations correlating the performance and noise of this fan prototype are executed inside AMCA test chamber and semianechoic chamber, respectively. Consequently, the feasibility of design scheme and numerical system can be verified according to these experimental results. In summary, this work provides a systematic scheme for designing and analyzing the in-line fan

Effect of Ethylenediaminetetraacetic Acid on Unsaturated Poly(Butylene Adipate-<i>Co</i>-Butylene Itaconate) Copolyester with Low-Melting Point and Controllable Hardness

A series of copolyesters, poly(butylene adipate-co-butylene itaconate) (PBABI), was synthesized using melt polycondensation from adipic acid (AA), itaconic acid (IA), 1,4-butanediol (1,4-BDO), and ethylenediaminetetraacetic acid (EDTA). 1H-NMR, FT-IR, GPC, DSC, TGA, DMA, XRD, Shore D, and tensile test were used to systematically characterize the structural and composition/physical properties of the copolyesters. It was found that the melting point (Tm) and crystallization temperature (Tc) of the copolyesters were, respectively, between 21.1 to 57.5 &#176;C and &#8722;6.7 to 29.5 &#176;C. The glass transition (Tg) and the initial thermal decomposition (Td-5%) temperatures of the PBABI copolyesters were observed to be between &#8722;53.6 to &#8722;55.8 &#176;C and 313.6 and 342.1 &#176;C at varying ratios of butylene adipate (BA) and butylene itaconate (IA), respectively. The XRD feature peak was identified at the 2&#952; values of 21.61&#176;, 22.31&#176;, and 23.96&#176; for the crystal lattice of (110), (020), and (021), respectively. Interestingly, Shore D at various IA ratios had high values (between 51.3 to 62), which indicated that the PBABI had soft plastic properties. The Young&#8217;s modulus and elongation at break, at different IA concentrations, were measured to be at 0.77&#8211;128.65 MPa and 71.04&#8211;531.76%, respectively, which could be attributed to a close and compact three-dimensional network structure formed by EDTA as a crosslinking agent. There was a significant bell-shaped trend in a BA/BI ratio of 8/2, at different EDTA concentrations&#8212;the ∆Hm increased while the EDTA concentration increased from 0.001 to 0.05 mole% and then decreased at an EDTA ratio of 0.2 mole%. Since the PBABI copolymers have applications in the textile industry, these polymers have been adopted to reinforce 3D air-permeable polyester-based smart textile. This kind of composite not only possesses the advantage of lower weight and breathable properties for textiles, but also offers customizable, strong levels of hardness, after UV curing of the PBABI copolyesters, making its potential in vitro orthopedic support as the &#8220;plaster of the future&#8222;

Effect of 1,2,4,5-Benzenetetracarboxylic Acid on Unsaturated Poly(butylene adipate-co-butylene itaconate) Copolyesters: Synthesis, Non-Isothermal Crystallization Kinetics, Thermal and Mechanical Properties

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8&ndash;49 &deg;C, 7.2&ndash;29 &deg;C and &minus;51.1 and &minus;58.1 &deg;C, respectively. Young&rsquo;s modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19&ndash;168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations

Sustainability and repeatedly recycled epoxy-based vitrimer electromagnetic shielding composite material

A series of electromagnetic interference (EMI) shielding composites composed of an epoxy-based vitrimer matrix and stainless-steel fabric was prepared in this study. The polymer matrix presents tunable mechanical properties and chemical recyclability through adjustment of the content ratio of soft aliphatic sebacic acid (SA) to rigid crosslinker 3-(carboxymethyl)cyclopentane-1,2,4-tricarboxylic acid (TCAA). All the recycled vitrimers exhibit strengths comparable to the original materials, suggesting that similar cross-linking structures were reformulated successfully. Furthermore, a noticeable enhancement in the mechanical strength is observed for the combination of matrix and stainless-steel fabric, indicating that the combination of vitrimer material and fabric is excellent. However, a certain extent of decreased mechanical abilities was observed for the composites after reclaiming, while no apparent differences are noted in the results between multiple recycling processes. This tendency may be attributed to the complex fabric structure, which allows a distinct distribution for the reclaimed matrix that is repolymerized by evaporating the solvent compared to the original polymer. In addition, the original and repeatedly recycled composites reveal comparable EMI shielding abilities of around 70 dB, demonstrating the potential for high performance when applied as EMI shielding materials

Digital Microfluidic Dynamic Culture of Mammalian Embryos on an Electrowetting on Dielectric (EWOD) Chip

<div><p>Current human fertilization <i>in vitro</i> (IVF) bypasses the female oviduct and manually inseminates, fertilizes and cultivates embryos in a static microdrop containing appropriate chemical compounds. A microfluidic microchannel system for IVF is considered to provide an improved <i>in-vivo</i>-mimicking environment to enhance the development in a culture system for an embryo before implantation. We demonstrate a novel digitalized microfluidic device powered with electrowetting on a dielectric (EWOD) to culture an embryo <i>in vitro</i> in a single droplet in a microfluidic environment to mimic the environment <i>in vivo</i> for development of the embryo and to culture the embryos with good development and live births. Our results show that the dynamic culture powered with EWOD can manipulate a single droplet containing one mouse embryo and culture to the blastocyst stage. The rate of embryo cleavage to a hatching blastocyst with a dynamic culture is significantly greater than that with a traditional static culture (<i>p</i><0.05). The EWOD chip enhances the culture of mouse embryos in a dynamic environment. To test the reproductive outcome of the embryos collected from an EWOD chip as a culture system, we transferred embryos to pseudo-pregnant female mice and produced live births. These results demonstrate that an EWOD-based microfluidic device is capable of culturing mammalian embryos in a microfluidic biological manner, presaging future clinical application.</p></div

Embryo transfer from EWOD embryos to pseudo-pregnant female mice.

<p>Panel A, Preparation of recipient mice for embryo transfer. Panel B, Pups was born after transfer of embryo cultured from EWOD. The recipients were allowed to deliver and raise pups.</p

Scheme of EWOD chip design and fabrication and principle of EWOD.

<p>A. Description of EWOD chip fabrication and bottom plate of EWOD chips (white scale bar, 6 mm). B. EWOD is based on the variation of the wettability of liquids on a dielectric solid surface on altering the electric potential. The contact angle of the liquid is decreased from its initial contact angle when a voltage is applied. On releasing the electric potential, the contact angle of the liquid reverts to the initial contact angle. C. Scheme of droplet transport.</p