Nanosecond-resolved temperature measurements using magnetic nanoparticles.

Magnetic fluid hyperthermia, as a novel cancer treatment, requires precise temperature control at 315 K–319 K (42 °C–46 °C). However, the traditional temperature measurement method cannot obtain the real-time temperature in vivo, resulting in a lack of temperature feedback during the heating process. In this study, the feasibility of temperature measurement and feedback control using magnetic nanoparticles is proposed and demonstrated. This technique could be applied in hyperthermia. Specifically, the triangular-wave temperature measurement method is improved by reconstructing the original magnetization response of magnetic nanoparticles based on a digital phase-sensitive detection algorithm. The standard deviation of the temperature in the magnetic nanoparticle thermometer is about 0.1256 K. In experiments, the temperature fluctuation of the temperature measurement and feedback control system using magnetic nanoparticles is less than 0.5 K at the expected temperature of 315 K. This shows the feasibility of the temperature measurement method for temperature control. The method provides a new solution for temperature measurement and feedback control in hyperthermia.

Research Article| February 01, 2012 Transient change in groundwater temperature after earthquakes Chi-yuen Wang; Chi-yuen Wang 1Earth & Planetary Science, University of California, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Michael Manga; Michael Manga 1Earth & Planetary Science, University of California, Berkeley, California 94720, USA Search for other works by this author on: GSW Google Scholar Chung-Ho Wang; Chung-Ho Wang 2Institute of Earth Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan Search for other works by this author on: GSW Google Scholar Chieh-Hung Chen Chieh-Hung Chen 2Institute of Earth Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan Search for other works by this author on: GSW Google Scholar Author and Article Information Chi-yuen Wang 1Earth & Planetary Science, University of California, Berkeley, California 94720, USA Michael Manga 1Earth & Planetary Science, University of California, Berkeley, California 94720, USA Chung-Ho Wang 2Institute of Earth Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan Chieh-Hung Chen 2Institute of Earth Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan Publisher: Geological Society of America Received: 20 Jun 2011 Revision Received: 25 Aug 2011 Accepted: 12 Sep 2011 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (2): 119–122. https://doi.org/10.1130/G32565.1 Article history Received: 20 Jun 2011 Revision Received: 25 Aug 2011 Accepted: 12 Sep 2011 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Chi-yuen Wang, Michael Manga, Chung-Ho Wang, Chieh-Hung Chen; Transient change in groundwater temperature after earthquakes. Geology 2012;; 40 (2): 119–122. doi: https://doi.org/10.1130/G32565.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Postseismic decrease in groundwater temperature was documented on the upper rim of a large alluvial fan near the epicenter of the 1999 Mw 7.5 Chi-Chi earthquake (Taiwan). We use a model of coupled heat transport and groundwater flow, constrained by documented water-level changes, to interpret this change. We show that groundwater temperature is sensitive to earthquake-induced flow and the observed temperature decrease may be explained by increased groundwater discharge due to earthquake-enhanced vertical permeability. The result implies that heat flow near active mountain fronts may be lowered by recurrent earthquakes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Transient temperature, another source to provide reservoir information besides transient pressure, has been received much attention in recent years. Different from the immediate response of transient pressure due to flow rate change, there are obvious time lags between the transient temperature change and flow rate change. In this paper, the nonsynchrony between PDG transient temperature, pressure and flow-rate data was quantitatively investigated with wavelet transform (WT). Field PDG data analysis show that transient pressure changes nearly at the same time of flow rate change. However, due to the adiabatic expansion/compression effect, the time lags between transient temperature and flow rate are significant and cannot be neglected. Field PDG data demonstrates that averagely transient temperature changes about 0.225 hours later than the flow rate. Accurately identifying the time of flow events from PDG temperature data is difficult. The identified flow event time from PDG temperature is the time when Joule-Thomson effect dominates the reservoir temperature change. The flow events with time periods less than the time lags cannot be identified from PDG temperature data due to the adiabatic expansion/compression effect. Compared with the Haar wavelet, the the second derivative of the Gaussian wavelet can more accurately identify flow events from PDG temperature data. This study will be useful for improving the accuracy of transient identification from PDG data, and can benefit transient temperature analysis by clarifying the time lags due to adiabatic expansion/compression effect, and synchronize PDG transient temperature, pressure and flow-rate data for better data processing and analysis.

A start-up behavior of a pulse tube refrigerator is experimentally investigated to gain a better understanding of the basic refrigeration mechanism. Two typical types of pulse tube refrigerators, which are a basic and an orifice pulse tube, are used. The pressure oscillation is introduced suddenly into the pulse tube under the uniform temperature, and the transient changes of gas temperature, wall temperature and heat out at the hot end are obtained as a time history from an onset of the pressure oscillation to an ultimate state that can be obtained after a long time. It is found that after only two cycles from the onset of pressure oscillation, the difference of gas temperature between the cold and the hot ends appears and it reaches to 65% level of the difference at the ultimate state. The heat out becomes stable after several hundreds of seconds. It is also found that the change of temperature at the very beginning of the oscillation is not adiabatic. Significant differences in the start-up behavior between a basic and an orifice pulse tube did not appear.KeywordsWall TemperaturePressure OscillationTemperature OscillationPulse TubeUltimate StateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Mechanisms Leading to Excess Alpha -Amylase Activity in Wheat (Triticum aestivum, L) Grain in the U.K

Transient changes of temperature and current were numerically analyzed in BaTiO3 semiconductors with a multilayer structure to which a constant electric field was applied. The numerical analysis required the radiation coefficient of the multilayer sample and the temperature dependence of resistivity of the material as input data. Temperature distribution of the sample was modeled to be uniform since the material possesses positive temperature coefficients of resistivity in the temperature range above the Curie point. The results of the numerical analysis agreed qualitatively with experimental results in the transient response, although the numerical analysis yielded some disagreements with experimental results when the applied electric field was low. The disagreements between analytical and experimental results are discussed with a focus on temperature distribution in samples.

Effects of microstructures and a transient temperature change on the microcracking of both cemented carbides and cermets were analyzed using a simulation method with a triangular elastic spring-lattice model. The transient temperature change was determined to fit the results of the improved thermal shock test which was proposed by Ishihara et al. The simulation results show that the initiations of a microcrack were observed at earlier stages of the transient temperature change for the models of both cemented carbides and cermets. Then, the successive occurrences of the microcracking were strongly affected by the microstructures. In the case of the large number of microcracks, the final number of microcracks for the transient calculation was different from one of a single step calculation.

TDL absorption sensors for gas temperature and concentrations in a high-pressure entrained-flow coal gasifier

When the temperature changes, the stress produced by the external constraint and the mutual constraint between the internal parts of the object, which makes it unable to expand and contract freely, is called thermal stress. The thermal stress is caused by the steady temperature field. When the transient temperature changes to zero and the temperature distribution reaches a stable state, the temperature distribution can be obtained from the heat conduction equation and temperature boundary conditions, and then the displacement and stress can be obtained from the elastic equation including the temperature term.

High-speed impact on spacecraft by space debris poses a threat. When a high-speed projectile collides with target, it is conceivable that the heat created by impact causes severe damage at impact point. Investigation of the temperature is necessary for elucidation of high-speed impact phenomena. However, it is very difficult to measure the temperature with standard methods for two main reasons. One reason is that a thermometer placed on the target is instantaneously destroyed upon impact. The other reason is that there is not enough time resolution to measure the transient temperature changes. In this study, the measurement of plasma induced by high-speed impact was investigated to estimate temperature changes near the impact point. High-speed impact experiments were performed with a vertical gas gun. The projectile speed was approximately 700 m/s, and the target material was A5052. The experimental data to calculate the plasma parameters of electron temperature and electron density were measured by triple probe method. In addition, the diffusion behavior of plasma was observed by optical visualization technique using high-speed camera. The frame rate and the exposure time were 260 kfps and 1.0 μs, respectively. These images are considered to be one proof to show the validity of plasma measurement. The experimental results showed that plasma signals were detected for around 70 μs, and the rising phase of the wave form was in good agreement with timing of optical visualization image when the plasma arrived at the tip of triple probe.

In the processing of titanium alloys, high temperatures at cutting interfaces lead to poor machinability and reduced machining efficiency. High-speed ultrasonic vibration cutting (HUVC) offers an improvement in heat dissipation compared to conventional cutting (CC), yet it loses its cooling advantage as cutting speeds further increase. To optimize efficiency, this study investigated transient cutting temperature variations using experimental measurements and finite element method (FEM) simulations to elucidate the cooling mechanisms in HUVC. An eroding junction thermocouple, along with stringent electromagnetic insulation measures, was employed to capture transient temperature changes with microseconds. The maximum discrepancy between measured and simulated temperatures in CC was found to be 13.8%, validating the feasibility of the FEM method for experimental supplementation and theoretical analysis in HUVC. The results indicated that HUVC reduced cutting temperatures by up to 40.7% compared to CC, with minimal differences in peak temperatures between HUVC and CC at identical cutting speeds. The cooling advantage in HUVC is attributed to temperature declines observed during the interface separation. The maximum temperature reduction ratio increased significantly from 40.9% to 77.1% with the rise in vibration amplitudes. Besides, an increase in tool clearance was found to improve cooling conditions in both CC and HUVC. This study introduced a novel method for ultrasonic temperature measurement in metal cutting, thereby advancing the understanding of cooling mechanisms at cutting interfaces in HUVC. Furthermore, modified process parameters were provided to achieve high-performance HUVC in machining difficult-to-cut alloys.

Introduction: Red blood cell(RBC), which passes through capillaries and exchanges O2 and CO2 with surrounding tissues, plays a very important in the blood circulation in the human body. Imbalance in blood circulation could lead to various cardiovascular related diseases such as high blood pressure, arteriosclerosis, diabetes, and stroke.[1] This is closely related to RBC aggregation. Negatively charged RBC membrane arranges a compact layer of positive ions around the membrane by electrical attraction with cations in plasma.The rearranged ions layer in plasma forms zeta potential with compact layer. When the electrostatic interaction between RBCs, i.e., zeta potential increases, RBC aggregation is improved. It is known that zeta potential depends on electronegativity of the RBC membrane, the dielectric constant of the medium and ionic strength [2]. Since pulsed magnetic field (PMF) influences human physiology, many clinical studies demonstrated the effect of PMF for wound healing, reducing pain, increasing angiogenesis, as well as improving blood circulation.[3-5] In this study, we have tried to elucidate the effect of PMF on RBC aggregation by indirectly observing zeta potential using negatively-charged magnetic beads(MB). Our hypothesis is that the increase of negative charges on RBC membrane results in the increase of cations in the compact layer, thus the increase of the zeta potential. As a result, the number of MB attached to the RBC increases, as the binding force between MB and compact layer increases.Experimental Method: Blood needed for experiment was obtained from Korean Red Cross after reviewing IRB exemption in Sangji University Bioethics Committee. Whole blood of 6 ml was centrifuged at 3000 rpm for 5 min in 4 oC for separating RBCs and plasma. MB used this experiment has diameter 1 μm with OH- groups (SiMAG-Silanol, Chemicell). To clearly see the MB attached to RBCs and, in addition, to avoid blood clots caused by proteins in plasma, RBC suspension of hematocrit (Ht) of 10% was prepared using PBS(phosphate buffer saline). The amount of MB added to RBC suspension was 0.5 mg. RBCs were also oxidative stressed with tBHP(Tert-Butyl hydroperoxide) in 0.4 mM at 37 oCincubator for 30 min, in order to confirm the change of RBCs membrane charge due to oxidative stress under PMF stimulus. In oxidative stressed RBCs, hemoglobin(Fe2+) is altered to methemoglobin(Fe3+) because of loss an electron, thereby, electronegativity of RBC membrane will be changed.[6] Each sample was exposed to PMF for 3 min. Our PMF stimulator system consisted of single layered coil of 10 turns with an elliptical shape of 12.0 x 4.5 cm. The maximum intensity is 0.27 T at a transition time of 0.102 ms, with pulse intervals of 1 Hz. The numbers of RBC attached MB were compared with control group and PMF treatment group. Only RBCs with a distance of about 1 μm between the MB and the surface of RBC were counted using hemocytometer.Results and Discussion: Fig.1. shows the numbers of RBCs according to the number of attached MB in the control and PMF treatment group. The numbers of RBCs attached MB increased after PMF treatment. The more the number of MBs attached to RBCs, the thicker the compact layer surrounding RBC membranes. This phenomenon might be inferred due to an increase of zeta potential, thereby, increase of negative charges on the RBC membrane. Thus, it can be interpreted that MB having hydroxide OH- group are more attached to RBCs via binding force between MB and compact layer. Also the numbers of MB in the group treated tBHP and the group exposed to PMF after tBHP treatment (tBHP+PMF) were compared in Fig.2. Although the number of MB attached to RBCs was 1~2 in tBHP group, after PMF stimulus, i.e. in tBHP+PMF group it appears the number of MB attached to RBCs increased up to 3~4. This might be explained that PMF affects the increase of RBC membrane charge on not only normal RBCs but also oxidative stressed RBCs. Therefore, it can be deduced that high instantaneous flux change of PMF improves the aggregation of RBCs by increasing the zeta potential, due to the increase of the membrane charge. **

Non-destructive thermal barrier coating (TBC) damage assessment using laser-induced luminescence and infrared radiometry

Exploration adsorption characteristics of zeolite 13X depending on humidity and flow rate in sorption thermal energy storage applications

Gridlike patterns of differing cell density were observed in evenly seeded cell monolayers. Such patterns were obtained in five of six cell lines tested, suggesting widespread occurrence. The mechanism appears to involve small, transient temperature changes related to incubator tray structure. The very short time course of appearance of the patterns implicates attachment rather than growth as the critically affected factor. Impaired adhesion or directed sedimentation resulting from thermally induced microcurrents in the medium are the two most likely mechanisms.