Wnt5a induces ROR1 to recruit cortactin to promote breast-cancer migration and metastasis.

ROR1 is a conserved oncoembryonic surface protein expressed in breast cancer. Here we report that ROR1 associates with cortactin in primary breast-cancer cells or in MCF7 transfected to express ROR1. Wnt5a also induced ROR1-dependent tyrosine phosphorylation of cortactin (Y421), which recruited ARHGEF1 to activate RhoA and promote breast-cancer-cell migration; such effects could be inhibited by cirmtuzumab, a humanized mAb specific for ROR1. Furthermore, treatment of mice bearing breast-cancer xenograft with cirmtuzumab inhibited cortactin phosphorylation in vivo and impaired metastatic development. We established that the proline at 841 of ROR1 was required for it to recruit cortactin and ARHGEF1, activate RhoA, and enhance breast-cancer-cell migration in vitro or development of metastases in vivo. Collectively, these studies demonstrate that the interaction of ROR1 with cortactin plays an important role in breast-cancer-cell migration and metastasis

Harmonic-Rejection Compact Bandpass Filter Using Defected Ground Structure for GPS Application

A miniaturized bandpass filter (BPF) using defected ground structure (DGS) resonator with the characteristic of harmonic rejection is developed in this paper. The second and third harmonics of the proposed BPF are rejected by the characteristic of stepped-impedance DGS resonator. Moreover, open stubs are established so that two adjustable transmission zeros can independently be created to extend the stopband and improve the rejection level. Finally, a second-order BPF, centered at 1.62 GHz with a stopband extended up to 5.6 GHz and a rejection level better than 20 dB, is designed and implemented for GPS application. A good agreement between simulation and measurement verifies the validity of this design methodology

Modeling and optimization for regenerator with heat recovery in liquid desiccant dehumidification system

As a broad and complex topic, energy efficiency has drawn an intensive attention in research community. Air Conditioning and Mechanical Ventilation (ACMV) systems in Singapore consume a substantial portion of energy in commercial buildings. Prioritizing high energy-efficiency ACMV system will deliver dramatic energy savings. Compared with conventional mechanical based air dehumidification schemes, liquid desiccant dehumidification system (LDDS) exhibits many advantages and demonstrates its superiority. Dehumidifier and regenerator are two major parts in LDDS, where the dehumidification and regeneration take place. Liquid desiccant solution is diluted in the dehumidifier since it absorbs excess moisture from the air. The diluted solution is re-concentrated in the regenerator. Majority of energy is consumed by regenerator in system operation in order to keep a suitable regenerating rate. Therefore, this thesis tries to put effort on energy saving of regenerator and mainly focus on waste heat recovery, modeling, design and operating optimization and performance evaluation. The main contributions of this thesis are summarized as below: 1. To reduce the amount of energy required to attain demanding regenerating performance, this thesis employs the waste heat recovery technique to reutilize the waste heat in the regenerating process. In the regenerator, the direct emission of the exhausted regenerating air, which holds high temperature and humidity, causes a great loss of heat. Thus, this part of heat can be recovered. Two heat recovery device, Heat Pipe Heat Exchanger (HPHE) and Fixed-plate Heat Exchanger (FPHE) are installed in regenerator to recover heat from the exhausted regenerating air to preheat the incoming air continuously. For the purpose of analyzing the heat recovery process, hybrid heat recovery model is established and validated by the experimental data. The model is simple and does not need iterative computation. It can be used to monitor and optimize the heat recovery performance in regenerator. The heat recovery efficiency under different working conditions of HPHE and FPHE can be predicted with the hybrid model. 2. To evaluate and compare the regenerator of Liquid Desiccant Dehumidification System (LDDS) without and with heat recovery, the performance analysis is conducted by hybrid heat transfer, mass transfer and heat recovery models, and the simulation results are then validated by the experimental results. Regenerator without heat recovery, with 4 rows HPHE, with 8 rows HPHE and with FPHE are compared to investigate the relationship between heat recovery rate and the additional fan energy consumption caused by the existence of heat recovery device. Many indexes are defined as the comparing criteria. Effects of air mass flow rate on the regenerating and heat recovery performance are also discussed. The results show that the numerical computation is effective and accurate. With heat recovery device, the regenerating performance is in general improved. 3. In order to find out the trade-off way between the regenerating performance and total pressure drop of the system, the multi-objective optimization is performed with pressure drop model, heat recovery model, heat transfer model and mass transfer model. Heat recovery device can recover waste heat and save the energy consumption of regenerator. However, its existence causes additional pressure drop. Other than heat recovery device, the structured packing is filled in regenerator tower to increase the contact area between regenerating air and liquid desiccant. It induces dramatic pressure drop due to the remarkable flow resistance. The dimension of structured packing, such as optimal height and diameter, affects the regenerating performance and pressure drop greatly. Optimal geometric dimension of packing can provide sufficient regenerating performance with acceptable pressure drop. Besides the design parameters in the optimization, operating parameters, especially air flow rate, also plays a significant role in energy saving and pressure drop.Doctor of Philosophy (EEE

Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating

The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on both two surfaces, namely, liquid aggregation and crown periphery instability; sub-droplet splashing and crown periphery instability; splashing and stable crown; and splashing with stable angle. However, the more wetting nanotube coated substrates push the transition between the patterns to a higher temperature. The quantitatively analysis of spreading length, diameter and height of crown and stable splashing angle further proved the transitions between the hydrodynamic patterns on the two titanium surfaces. The instability at the crown periphery may result from the low surface tension of the working fluids in first and second patterns, while the crown becomes stable on the third pattern. In the fourth pattern, a sharp shift of the splashing angle from decreasing to increasing is found at the surface temperature of 323 ∘C and 404 ∘C for the bare titanium surface and the nanotube coated surface, respectively. The shift could be attributed to the emergence of Leidenfrost effect. It is found that the Leidenfrost point at the droplet train impingement on the nanotube coated surface has been remarkably delayed.Accepted versio

Design and optimization of conformal cooling channels for injection molding : a review

The recent developments in the additive manufacturing make easier and affordable the fabrication of conformal cooling channels (CCCs) compared with the traditional machining techniques. Conformal cooling channels (CCCs) achieve better cooling performances than the conventional (straight-drilled) channels during the injection molding process since they can follow the pathways of the molded geometry while the conventional channels fail. Cooling time, total injection time, uniform temperature distribution, thermal stress, warpage thickness, etc. are some of the objectives that are improved via CCC applications. However, the CCC design process is more complex than the conventional channels; therefore, computer-aided engineering (CAE) simulations have significant importance for the effective and affordable design. This review study presents the main design steps of CCCs as follows: (1) a background of the CCC fabrication process is projected, (2) the thermal and mechanical models are presented with respect to the 1D analytical model, (3) the CAE-supported design criteria are discussed for the 3D models of CCCs and relevant mold materials, (4) some of the illustrative CAE simulations are explained in detail according to the computational thermal and mechanical objectives, and (5) the single- and multi-objective optimization procedures are defined. By following the aforementioned steps, clearer and effective CAE steps can be obtained for the designers before the on-site fabrication of CCCs

Dynamic Analysis of an Energy Efficiency Dehumidifier for Building Applications

This paper presents a dynamic analysis of an energy efficiency dehumidifier for building applications. This new structured dehumidifier is working with a controllable desiccant concentration, and the dynamic behavior of the heat and mass transfer process inside the dehumidifier becomes rather critical. A model is developed to describe the dynamic behavior of the process air with experimental validation. The numerical results of the dynamic response are clarified to conclude that decreasing the solution inlet temperature has a more significant impact on improving the dehumidification ability than increasing solution mass flow rate. The outcomes provide a comprehensive understanding of the dynamic behavior and the results will benefit the humidity control of the indoor air to improve the living quality of the occupants.NRF (Natl Research Foundation, S’pore)Accepted versio

Thermal and mechanical assessments of the 3D-printed conformal cooling channels : computational analysis and multi-objective optimization

Conformal cooling is an additive manufacturing-based solution and it is a rapidly developing method for reducing the cooling time of the plastic injection process. The present study investigates the thermal and mechanical performances of the 3D-printed conformal cooling channels using computational analyses and multi-objective optimization. For a real injection mold product, two different conformal cooling channel profiles, which are circular and elongated, are analyzed individually. Their cooling time, temperature non-uniformity, and pressure drop are assessed. Compared to the traditional channels, the cooling time of designed CCCs is reduced in the range of 30-60%. The cooling and fatigue life performances of the elongated channel are analyzed for different channel pathways and cross section areas. As for the circular channel, the coolant temperature, volume flow rate, and channel diameter are selected as the parameters within the ranges of 288.0-298.0 K, 1.0-10.0 L/min, and 2.1-2.5 mm, respectively. According to these parameters, the multi-objective optimization study is performed and the best trade-off point is found at the channel diameter of 2.5 mm, coolant temperature of 297 K, and the flow rate of 1 L/min when all the objectives have equal weights in the optimization problem.Accepted versio

Performance investigation on a novel liquid desiccant regeneration system operating in vacuum condition

Liquid Desiccant Dehumidification Systems (LDDS) have been gaining attention due to its great energy saving potential in buildings. The desiccant regeneration system in LDDS plays a vital role in the system as the major energy consumed is due to the heat energy supplied to regain the concentration of the desiccant solution. The high regeneration temperature prohibits the potential use of low-grade or renewable energy as the heat source in the desiccant regeneration system. Therefore, a desiccant regeneration system operating in vacuum condition was proposed in this work. A novel Absorption-based Liquid Desiccant Regeneration (ALDR) system was developed and studied to validate this approach. A performance prediction model was also developed to predict the regeneration performance of the ALDR system. The model predicted values and the experimental values agreed well with each other with average deviation less than 5.90%. The operating parameters in the proposed ALDR system were also compared with the conventional packed-bed desiccant regeneration system available in literature. The regeneration temperature in LDDS was found to be significantly reduced to around 20–35 °C with the operating vacuum pressure between 1000 Pa and 2000 Pa when regenerating Lithium Bromide solution of 36% mass fraction. This study validated the feasibility of the ALDR system in reducing the regeneration temperature of the desiccant regeneration system. The results also showed that the proposed ALDR system was able to reduce the power consumption by 40.66% compared to the conventional packed-type regenerator from literature.NRF (Natl Research Foundation, S’pore

A cryogenic sensor based on fiber Bragg grating for storage monitoring of liquefied natural gas

Condition monitoring is critical for the safe usage of Liquefied Natural Gas (LNG). Temperature distribution is an important index of LNG storage and it can reflect the tendency of heat leakage and the situation of evaporation. However, traditional electric sensor may cause explosion due to spark. In this paper, a cryogenic sensor based on fiber Bragg grating (FBG) is developed in which the fiber with pre-tensile force is adhered onto temperature-sensitive metal. The liquefied nitrogen (LN2) is used to test the designed sensor instead of LNG for safety consideration. By setting every 10 K as a testing point from 83 K to 193 K, the experimental investigation reveals that there is a positive linear relation between the reflected wavelength and the testing temperature. By using multiple linear functions to fit experimental data, the maximum measuring error of FBG sensor is less than ±0.35 K, which indicates the usability of this sensor in LNG storage. Finally, an experiment of temperature stratification is performed to validate usability of FBG sensor for LNG monitoring. The results indicate that the designed FBG sensor has enough accuracy to reveal LNG rollover and it has similar dynamic performance with RTD sensor.NRF (Natl Research Foundation, S’pore