Verification of Thermal Comfort of Combined Convection-Radiation Air Conditioning System using Building Structure

Combined Convection-Radiation Air Conditioning System using Building Structure combines the advantages of TABS and convection air conditioning. In ordinary TABS, pipes are buried in the frame, but here pipes are laid on the lower (ceiling) surface of the floor slab. Also, jets from a Convection-enhancing Spot fan are sprayed toward the ceiling surface, promoting convection on the frame surface. This airflow promotes timely heat dissipation stored in the frame, and a micro-airflow environment can be formed in the living area. This paper aimed to verify thermal comfort and proper operation. Subjects were given simulated work of low to high metabolic rate, and were asked to report the thermal sensation and comfort in a micro-airflow environment. It was confirmed that comfort could be maintained even at a temperature higher than the general air-conditioning temperature, and an appropriate operating method according to the metabolic rate was elucidated.publishedVersio

Precise measurement of positronium hyperfine splitting using the Zeeman effect

Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, $\Delta_{\mathrm{HFS}}$, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15\,ppm (3.9$\sigma$) of $\Delta_{\mathrm{HFS}}$ between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of $\Delta_{\mathrm{HFS}} = 203.395\,1 \pm 0.002\,4 (\mathrm{stat.}, 12\,\mathrm{ppm}) \pm 0.001\,9 (\mathrm{sys.}, 9.5\,\mathrm{ppm})\,\mathrm{GHz}$ has been obtained so far. A measurement with a precision of $O$(ppm) is expected within a year.Comment: 8 pages, 8 figures, 2 tables, proceeding of LEAP2011, accepted by Hyperfine Interaction

Persimmon Tannin Gel: Formation by Autoxidation and Caffeine Adsorption Properties

金沢大学理工研究域物質化学系Water-insoluble gel was prepared from persimmon tannin (PT) solution by the autoxidation process. The gelation reaction proceeded by applying oxygen gas and natural light to the aqueous PT solution, without using harmful reagents or catalysts. Adsorption behavior of the PT gel was assessed using caffeine. Batch adsorption studies were conducted to evaluate the influence of experimental parameters such as contact time, initial concentration of adsorbates, adsorbent dose and temperature. The equilibrium data were analyzed using Freundlich and Langmuir isotherm models. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy changes were also calculated, showing that caffeine adsorption on the PT gel is an exothermic process and feasible at lower temperatures. The present results suggest that the PT gel can be used as an effective adsorbent for removing caffeine from solutions.出版者照会後に全文公

Variation in target volume and centroid position due to breath holding during four-dimensional computed tomography scanning: A phantom study

This study investigated the effects of respiratory motion, including unwanted breath holding, on the target volume and centroid position on four‐dimensional computed tomography (4DCT) imaging. Cine 4DCT images were reconstructed based on a time‐based sorting algorithm, and helical 4DCT images were reconstructed based on both the time‐based sorting algorithm and an amplitude‐based sorting algorithm. A spherical object 20 mm in diameter was moved according to several simulated respiratory motions, with a motion period of 4.0 s and maximum amplitude of 5 mm. The object was extracted automatically, and the target volume and centroid position in the craniocaudal direction were measured using a treatment planning system. When the respiratory motion included unwanted breath‐holding times shorter than the breathing cycle, the root mean square errors (RSME) between the reference and imaged target volumes were 18.8%, 14.0%, and 5.5% in time‐based images in cine mode, time‐based images in helical mode, and amplitude‐based images in helical mode, respectively. In helical mode, the RSME between the reference and imaged centroid position was reduced from 1.42 to 0.50 mm by changing the reconstruction method from time‐ to amplitude‐based sorting. When the respiratory motion included unwanted breath‐holding times equal to the breathing cycle, the RSME between the reference and imaged target volumes were 19.1%, 24.3%, and 15.6% in time‐based images in cine mode, time‐based images in helical mode, and amplitude‐based images in helical mode, respectively. In helical mode, the RSME between the reference and imaged centroid position was reduced from 1.61 to 0.83 mm by changing the reconstruction method from time‐ to amplitude‐based sorting. With respiratory motion including breath holding of shorter duration than the breathing cycle, the accuracies of the target volume and centroid position were improved by amplitude‐based sorting, particularly in helical 4DCT

Verification of Thermal Comfort of Combined Convection-Radiation Air Conditioning System using Building Structure

Combined Convection-Radiation Air Conditioning System using Building Structure combines the advantages of TABS and convection air conditioning. In ordinary TABS, pipes are buried in the frame, but here pipes are laid on the lower (ceiling) surface of the floor slab. Also, jets from a Convection-enhancing Spot fan are sprayed toward the ceiling surface, promoting convection on the frame surface. This airflow promotes timely heat dissipation stored in the frame, and a micro-airflow environment can be formed in the living area. This paper aimed to verify thermal comfort and proper operation. Subjects were given simulated work of low to high metabolic rate, and were asked to report the thermal sensation and comfort in a micro-airflow environment. It was confirmed that comfort could be maintained even at a temperature higher than the general air-conditioning temperature, and an appropriate operating method according to the metabolic rate was elucidated

Baseline correction of a correlation model for improving the prediction accuracy of infrared marker-based dynamic tumor tracking

We previously found that the baseline drift of external and internal respiratory motion reduced the prediction accuracy of infrared (IR) marker-based dynamic tumor tracking irradiation (IR Tracking) using the Vero4DRT system. Here, we proposed a baseline correction method, applied immediately before beam delivery, to improve the prediction accuracy of IR Tracking. To perform IR Tracking, a four-dimensional (4D) model was constructed at the beginning of treatment to correlate the internal and external respiratory signals, and the model was expressed using a quadratic function involving the IR marker position (x) and its velocity (v), namely function F(x, v). First, the first 4D model, F1st(x, v), was adjusted by the baseline drift of IR markers (BDIR) along the x-axis, as function F′(x, v). Next, BDdetect, that defined as the difference between the target positions indicated by the implanted fiducial markers (Pdetect) and the predicted target positions with F′(x, v) (Ppredict) was determined using orthogonal kV X-ray images at the peaks of the Pdetect of the end-inhale and end-exhale phases for 10 s just before irradiation. F′(x, v) was corrected with BDdetect to compensate for the residual error. The final corrected 4D model was expressed as Fcor(x, v) = F1st{(x-BDIR), v}-BDdetect. We retrospectively applied this function to 53 paired log files of the 4D model for 12 lung cancer patients who underwent IR Tracking. The 95th percentile of the absolute differences between Pdetect and Ppredict (|Ep|) was compared between F1st(x, v) and Fcor(x, v). The median 95th percentile of |Ep| (units: mm) was 1.0, 1.7, and 3.5 for F1st(x, v), and 0.6, 1.1, and 2.1 for Fcor(x, v) in the left–right, anterior–posterior, and superior–inferior directions, respectively. Over all treatment sessions, the 95th percentile of |Ep| peaked at 3.2 mm using Fcor(x, v) compared with 8.4 mm using F1st(x, v). Our proposed method improved the prediction accuracy of IR Tracking by correcting the baseline drift immediately before irradiation

Long-term stability assessment of a 4D tumor tracking system integrated into a gimbaled linear accelerator

We assessed long-term stability of tracking accuracy using the Vero4DRT system. This metric was observed between September 2012 and March 2015. A programmable respiratory motion phantom, designed to move phantoms synchronously with respiratory surrogates, was used. The infrared (IR) markers moved in the anterior-posterior (AP) direction as respiratory surrogates, while a cube phantom with a steel ball at the center, representing the tumor, and with radiopaque markers around it moved in the superior-inferior (SI) direction with one-dimensional (1D) sinusoidal patterns. A correlation model between the tumor and IR marker motion (4D model) was created from the training data obtained for 20 s just before beam delivery. The irradiation field was set to 3× 3cm2 and 300 monitor units (MUs) of desired MV X-ray beam were delivered. The gantry and ring angles were set to 0o and 45o, respectively. During beam delivery, the system recorded approximately 60 electronic portal imaging device (EPID) images. We analyzed: 1) the predictive accuracy of the 4D model (EP), defined as the difference between the detected and predicted target positions during 4D model creation, and 2) the tracking accuracy (ET), defined as the difference between the center of the steel ball and the MV X-ray field on the EPID image. The median values of mean plus two standard deviations (SDs) for EP were 0.06, 0.35, and 0.06mm in the left-right (LR), SI, and AP directions, respectively. The mean values of maximum deviation for ET were 0.38, 0.49, and 0.53mm and the coefficients of variance (CV) were 0.16, 0.10, and 0.05 in lateral, longitudinal, and 2D directions, respectively. Consequently, the IR Tracking accuracy was consistent over a period of two years. Our proposed method assessed the overall tracking accuracy readily using real-time EPID images, and proved to be a useful QA tool for dynamic tumor tracking with the Vero4DRT system