An innovative α‐calcium sulfate hemihydrate bioceramic as a potential bone graft substitute

The microstructural, in vitro and in vivo properties of the microwave‐synthesized samples were investigated using the optical microscope, scanning electron microscope, X‐ray diffraction, differential scanning calorimeter, contact angle goniometer, cell cytotoxicity assay, and chick chorioallantoic membrane (CAM) model in the study. When the calcium sulfate dihydrate (CSD) precursor underwent microwave irradiation treatment at temperatures between 100°C and 160°C, the crystal morphologies and crystalline structures were transformed from (tablet‐like CSD (monoclinic)) → (tablet‐like CSD (monoclinic) + long column α‐calcium sulfate hemihydrate (α‐CSH, hexagonal)) → (long column CSD (monoclinic) + short column α‐CSH (hexagonal)) → (uniform short column α‐CSH (hexagonal)). The high‐purity α‐CSH with uniform short column crystals around 10 μm in length can be synthesized at 160°C for 10 minutes and exhibits a higher hydrophilic feature in blood. Moreover, the cell cytotoxicity assay indicated that the microwave‐synthesized samples possessed well biocompatibility. In vivo results also demonstrated that the microwave‐synthesized α‐CSH not only induces angiogenesis formation but also facilitates osteogenesis. Therefore, the microwave‐synthesized α‐CSH is a promising bone graft substitute that can be applied in dental and orthopedic fields.     

One‐pot synthesis of sheet‐like MFI as high‐performance catalyst for toluene disproportionation

In this study, one‐pot hydrothermal synthesis of sheet‐like ZSM‐5 as a high‐performance catalyst for toluene disproportionation was carried out using binary surfactants. In the dual template, tetraethylammonium hydroxide was used to construct the microporous structure of ZSM‐5, and cationic surfactant (e.g., octadecyltrimethylammonium chloride (C₁₈TMAC), hexadecyltrimethyl ammonium bromide (C₁₆TMAB), and tetradecyltrimethylammonium bromide, (C₁₄TMAB)) can change the growth habits of the ZSM‐5 crystals by hindering the regular stacking of zeolite layers from their longer hydrophobic chain. From the XRD pattern of the as‐synthesized samples which were hydrothermally treated for different time, it was found that a lamellar mesostructured intermediate gradually transformed into the sheet‐like ZSM‐5 during hydrothermal process. With a proper amount of cationic surfactant, the thickness of the sheet‐like ZSM‐5 could be controlled to less than 30 nm. Concerning the catalyst application, the toluene disproportionation performance over the sheet‐like ZSM‐5 is 1.5 times higher than that of the commercial ZSM‐5. The higher conversion is ascribed to the faster diffusion amount due to the sheet‐like ZSM‐5.     

A study of flow patterns for staggered cylinders at low Reynolds number by spectral element method

This study investigates the pattern of flow past two staggered array cylinders using the spectral element method by varying the distance between the cylinders and the angle of incidence (α) at low Reynolds numbers (Re = 100-800). Six flow patterns are identified as Shear layer reattachment (SLR), Induced separation (IS), Vortex impingement (VI), Synchronized vortex shedding (SVS), Vortex pairing and enveloping (VPE), and Vortex pairing splitting and enveloping (VPSE). These flow patterns can be transformed from one to another by changing the distance between the cylinders, the angle of incidence, or Re. SLR, IS and VI flow patterns appear in regimes with small angles of incidence (i.e., α ≤ 30° ) and hold only a single von Karman vortex shedding in a wake with one shedding frequency. SVS, VPE and VPSE flow patterns appear in regimes with large angles of incidence (i.e., 30° ≤ α ≤ 50° ) and present two synchronized von Karman vortices. Quantitative analyses and physical interpretation are also conducted to determine the generation mechanisms of the said flow patterns.     

A wireless brainwave-driven system for daily-life analyses and applications

Smartphones have become more popular in our lives. We will no longer need to use our hands to control phones to do such things as take pictures, switch music, or make phone calls in the future; we will use our brains: all that can be controlled with the use of brainwaves instead. In this study, we implement a novel system that contains the most commonly used functions of a smartphone, including camera use and music play, with an app that uses brainwave controls. In addition, we also provide an essential daily-use function which can remind us to concentrate when we drive, study, or do something important. Under the proposed system, when the wireless brainwave instrument is worn, brainwave signals transfer to the smartphone via Bluetooth automatically and execute the aforementioned functions. Experimental results indicate that the present system is effective and suitable for such applications in our lives. In the future, some more related applications will be developed with brainwave control for practical daily-life uses.     

A Pragmatic Design for 3GPP/WLAN RAN Level Interworking

Wireless Personal Communications - As mobile data traffic continues to grow significantly, traffic offloading is an important issue. Since WiFi-capable user equipments (UEs) are very popular...     

An efficient resource management scheme in light-trail networks

Light-trail, a framework proposed in the past few years, is generalized from the concept of lightpath, and its distinguishing features include bandwidth sharing and efficient bandwidth utilization. Performance of light-trail networks depends on the routing algorithm and the dynamic bandwidth allocation (DBA) scheme, and the former issue has been discussed extensively. In this work, we aim at the design of an efficient DBA scheme, named Demand and Delay-latency Aware with Two-round Deliberation \((\hbox {D}^{2}\hbox {ATD})\), to allocate bandwidth more accurately and efficiently in light-trail networks. In addition to DBA issue, \(\hbox {D}^{2}\hbox {ATD}\) includes a light-trail setup/release mechanism as well. As expected, the simulation results reveal superiority of \(\hbox {D}^{2}\hbox {ATD}\) in both blocking performance and delay performance. Although \(\hbox {D}^{2}\hbox {ATD}\) pays a price of control overhead for performance gain, it is still reasonable since the amount of control messages does not exceed the capacity of the control channel. It verifies that \(\hbox {D}^{2}\hbox {ATD}\) can properly employ the control channel to achieve excellent performance.     

Nonparametric Identification of a Building Structure from Experimental Data Using Wavelet Neural Network

Abstract:   This study presents a wavelet neural network-based approach to dynamically identifying and modeling a building structure. By combining wavelet decomposition and artificial neural networks (ANN), wavelet neural networks (WNN) are used for solving chaotic signal processing. The basic operations and training method of wavelet neural networks are briefly introduced, since these networks can approximate universal functions. The feasibility of structural behavior modeling and the possibility of structural health monitoring using wavelet neural networks are investigated. The practical application of a wavelet neural network to the structural dynamic modeling of a building frame in shaking tests is considered in an example. Structural acceleration responses under various levels of the strength of the Kobe earthquake were used to train and then test the WNNs. The results reveal that the WNNs not only identify the structural dynamic model, but also can be applied to monitor the health condition of a building structure under strong external excitation.     

高雄捷運明挖隧道施工交通維持與管控

高雄都會區人口密集區正在興建大眾捷迎系統:車站明挖、潛盾隧道出土及橫坑地表灌漿等,若没有作好施工中的交通維持與管控,將可能造成交通壅塞的黑暗期,進而引發民怨與延誤工程進度。敍述在用路人行的權益第一之前提下,如何興建都會捷運明挖隧道之柔性施工管理技術,諸如交通衝擊分析與減輕方案及施工配合措施與管理等。     

Measurement of the Reynolds stress structure and turbulence characteristics of the wind above a two-dimensional trapezoidal shape of hill

Wind tunnel experiments were carried out to measure the mean velocity and turbulence structure of the wind flow over a two-dimensional trapezoidal shape of hill. The quadrant analysis technique was employed to analyze the structure of the Reynolds stress. Analysis of the turbulent velocity spectrum of the wind above the hill under different wind attack angles is conducted. The fractional speed-up ratios of the present measured results are found in agreement with the wind tunnel data of Lemelin et al. (J. Wind Eng. Ind. Aerodyn. 28 (1988) 117) for the case of the wind attack angle of 30°. Measurements of the mean velocity profiles disclose that the speed-up phenomenon is mostly manifest at Z/H=0.6 for the case of wind attack angle of 10°. Turbulence intensity profiles measured at different locations show that the turbulence intensity decreases as shifting from far upstream location of the hill (X/H=−20) to the downstream location at the center of hill (X/H=0). The decrease of the turbulence intensity is obviously at the distance close to the surface of the hill. Results of the quadrant analysis indicate that the sweep and ejection events are the major contributors to the Reynolds stress. Others like inward and outward interaction events make negative contributions. The values of the stress fractions of ejection and sweep events become the lowest as the wind attack angle is 20°. Analysis of the turbulent velocity power spectrum density shows that the spectrum density is increasing in the lower-frequency region as the wind attack angle increases. The power spectrum density is found to decrease for increase in the wind attack angle at the higher-frequency region.