Development of hybrid loop heat pipe using pump assistance for cooling application on high heat flux device

Loop heat pipe (LHP) is an effective two-phase heat transfer device that utilizes evaporation and condensation of a working fluid. LHP is widely used in a passive cooling system, highly reliable and a very high thermal conductive device. However, extreme power density can cause dry-out in the evaporator section of LHP and might hinder the performance of the cooling system. The purpose of this research is to design and manufacture a new prototype of LHP by modifying the conventional LHP. The modification was performed by adding a diaphragm pump, called hybrid loop heat pipe (HLHP). The experimental results show that the installation of pumps in the modified LHP was able to prevent the occurrence of a dry out and reduce the operating temperature. Under a constant conductance mode, the pump was activated for 20 minutes and succeded in forcing the system to a new stable condition with a significant temperature drop. These results indicate that HLHP is very promising as a two-phase cooling system that can be proposed for devices that produce high heat flux.

     

Discovery of a New Class of Non‐imidazole Oxazoline‐Based Histamine H3 Receptor (H3R) Inverse Agonists

H ₃ R inverse agonists based on an aminopropoxy‐phenyloxazoline framework constitute highly valuable druglike lead compounds that display efficacy in a mouse model of recognition memory.

     

Nonlinear correlation spectroscopy (NLCS)

We present a novel concept for optical spectroscopy called nonlinear correlation spectroscopy (NLCS). NLCS analyses coherent field fluctuations of the second and third harmonic light generated by diffusing nanoparticles. Particles based on noncentrosymmetric nonlinear materials such as KNbO(3) show a strong second as well as third harmonic response. The method and the theory are introduced and experimental NLCS results in fetal calf serum are presented showing the promising selectivity of this technique for measurement in complex biological environments.     

Highly sensitive pyrogen detection on medical devices by the monocyte activation test

Pyrogens are components of microorganisms, like bacteria, viruses or fungi, which can induce a complex inflammatory response in the human body. Pyrogen contamination on medical devices prior operation is still critical and associated with severe complications for the patients. The aim of our study was to develop a reliable test, which allows detection of pyrogen contamination on the surface of medical devices. After in vitro pyrogen contamination of different medical devices and incubation in a rotation model, the human whole blood monocyte activation test (MAT), which is based on an IL-1β-specific ELISA, was employed. Our results show that when combining a modified MAT protocol and a dynamic incubation system, even smallest amounts of pyrogens can be directly detected on the surface of medical devices. Therefore, screening of medical devices prior clinical application using our novel assay, has the potential to significantly reduce complications associated with pyrogen-contaminated medical devices.     

Graphene oxide influence on selected properties of polymer fuel cells based on Nafion

Graphene oxide (GO) was used as an additive to the anode, to modify the electrochemical properties of polymer fuel cells (PEMFC) based on Nafion. GO was obtained by modified Hummers method and fully characterized by Raman, FTIR, X-ray, TEM, electrochemically (CV) and Surface Area and Porosity Analyzer. PEMFC with a GO-based anode containing about 30% less Pt, was constructed and compared with a cell with standard anodes. The electrodes were electrochemically tested at 25 and 60 °C. A maximum power density of 134 mW/cm² with a current density of 374 mA/cm² was achieved for PEMFC with GO-based anode at 60 °C. The electrochemical surface area (ECSA) of the PEMFC with GO-based anode was about two times higher than that of the reference device. The electrochemical characterization as well as the Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analysis indicate that GO in the anode reduced Pt agglomeration, as a consequence of the increased surface area and decreased average pore width, compared with the reference electrode. Well-fitted equivalent circuits were proposed and discussed after an electrochemical impedance spectroscopy study of the constructed devices.     

Bird migration flight altitudes studied by a network of operational weather radars

A fully automated method for the detection and quantification of bird migration was developed for operational C-band weather radar, measuring bird density, speed and direction as a function of altitude. These weather radar bird observations have been validated with data from a high-accuracy dedicated bird radar, which was stationed in the measurement volume of weather radar sites in The Netherlands, Belgium and France for a full migration season during autumn 2007 and spring 2008. We show that weather radar can extract near real-time bird density altitude profiles that closely correspond to the density profiles measured by dedicated bird radar. Doppler weather radar can thus be used as a reliable sensor for quantifying bird densities aloft in an operational setting, which—when extended to multiple radars—enables the mapping and continuous monitoring of bird migration flyways. By applying the automated method to a network of weather radars, we observed how mesoscale variability in weather conditions structured the timing and altitude profile of bird migration within single nights. Bird density altitude profiles were observed that consisted of multiple layers, which could be explained from the distinct wind conditions at different take-off sites. Consistently lower bird densities are recorded in The Netherlands compared with sites in France and eastern Belgium, which reveals some of the spatial extent of the dominant Scandinavian flyway over continental Europe.     

鄂尔多斯博物馆

精选理由步入博物馆的一刹那,好像进入了一个明亮而巨大的洞窟,与外界形成巨大反差的峡谷空间展现在眼前,人们相遇在这原始而又未来,传统而又当代的景观中,开始一段奇妙的时空旅程。     

Autonomous vacuum cleaner

This paper presents the results of the development of an autonomous mobile robot, designed according to some new concepts established in this field during the last decade. These principles can be found in other works based on the constructivist approach, artificial life, subsumption architecture and other bottom-up methodologies. These ideas have been applied to the complete robot design, spanning from the shape of the robot to the sensors, from the electronics to the software control structure. By this way we have developed what we call an “Application Specific Mobile Robot” (ASMR). The target application is a domestic autonomous vacuum cleaner. Despite the actual limitations of the final robot, this work shows how this methodology can bring many interesting results.     

Liquid-crystalline phases formed by symmetrical azines with different terminal chains: Thermal,optical and electrical study

One series of symmetrical azine-type liquid crystals were synthesized and their chemical structure identified by FTIR, NMR, high resolution mass spectrometry-electro spray ionization (MS-ESI) and elemental analysis. The absorption (UV–vis), photoluminescence (PL) and thermoluminescence (TL) features of the compounds are documented. X-ray diffraction was employed to evaluate their phase transitional behaviour. Their mesomorphic properties were investigated by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). Terminal groups of the liquid crystals had an effect on their mesomorphic properties. Azine with alkoxysemiperfluorinated end-groups (A1) exhibited smectic C (SmC) phase, whereas azine with octadecyloxy end chains (A3) showed SmC and SmA phases. Azine with 5″-octyl-2,2′:5′,2″-terthiophene groups (A2) exhibited only nematic phase. Different types of N and SmC textures were found and investigated by POM technique. Azine with thiophene groups (A2) has an absorption band about 138 nm batochromically shifted compared to the analogous band of other compounds. The lowest optical band gap value (2.34 eV) was detected for A2. Azines emitted violet or green light. The thermoluminescence emission of azines occurred at about 390–440 nm wavelengths. Current–voltage measurements were performed on ITO/compound/Alq₃/Al and ITO/TiO₂/compound/Alq₃/Al devices before and after light irradiation. To prepare TiO₂ layer, sol–gel technique was applied.