176 research outputs found
Prediction of the long-term performance of vacuum insulation panel installed in real building environments
Vacuum insulation panels (VIPs) are high-performance insulating materials constructed by covering a core and adsorbent with an envelope and evacuating the air from the inside. VIPs have used to enhance the energy efficiency of devices including refrigerators, vending machines, and cooler boxes. In order to apply VIPs as heat-insulation materials in buildings and houses, it is necessary to predict the long-term performance of the VIPs and verify the accuracy of the prediction using actual measurements. VIPs using glass fiber as a core material are spreading in Japan, and VIPs using glass fiber core material as the core is also likely to be the mainstream in building applications. Therefore, in this paper, we report the comparison of the measurement results of the long-term performance in the building environment of VIPs using glass fiber and the calculation result. We also describe the calculation method of long-term performance prediction
Distribution of Hyperfine Fields in Magnetically Anisotropic Amorphous Fe_<100-x>B_x Alloys
The temperature dependence of the Mossbauer spectra of the amorphous Fe_B_x (x=14~21) alloys has been measured. The two distributions of intensity, I_ (H) and I_2(H), which are associated with (±3/2-±1/2) and (±1/2-^-_+1/2), and with (±1/2-±1/2) transitions, respectively, are calculated from the spectra separately. The fact that the shapes of I_2(H) are different from those of I_ (H) at 20K gives evidence that the magnitude and direction of hyperfine fields are not independent of each other, but are correlated. The ratio of the average fields H_2, derived from I_2(H), to H, derived from the hyperfine field distribution P(H), at 20K is dependent on the boron concentration. It is considered that there exists a spatial fluctuation of composition in the samples, and that in the regions where x=17 the magnetization changes its direction easily from parallel to perpendicular to the sample plane, under the stresses caused by decreasing temperature
The Curie Temperature of Magnetically Inhomogeneous Amorphous Fe-Zr-B Alloys
The Curie temperature of amorphous Fe-Zr-B alloys was determined by both the Mossbauer thermal scan and a modified Arrott-plots methods. For amorphous Fe_(Zr_B_x)_8 alloys, the two methods make a difference between the values of T_c. On the other hand, for amorphous Fe_(Zr_B_x)_ alloys, the results of the two methods agree with each other within limits of the experimental error. It is found that the magnetic inhomogeneity often causes the difficulty in the determination of T_c and the measurement of T_c necessitating external fields is accompanied by a serious problem in the case of the magnetically inhomogeneous materials. Since no external field is necessary, the Mossbauer thermal scan method is very useful for determining T_c of amorphous alloys containing Fe atoms
Magnetization and neutron-diffraction studies of magnetic properties of single-crystal DyMn2Ge2
Insulin resistance and subclinical abnormalities of global and regional left ventricular function in patients with aortic valve sclerosis
BACKGROUND: Insulin resistance, as a key mediator of metabolic syndrome, is thought to be associated with pathogenesis of calcific aortic valve disease and altered left ventricular (LV) function and structure. However, in patients with aortic valve sclerosis (AVS), the association between insulin resistance and subclinical impairment of LV function is not fully elucidated. METHODS: We studied 57 patients (mean age 70 ± 8 years, 22 women) with asymptomatic AVS but normal LV ejection fraction in echocardiography. LV longitudinal and circumferential strain and strain rate was analyzed using two-dimensional speckle tracking echocardiography. Patients with uncontrolled hypertension and diabetes mellitus, chronic kidney disease, and concomitant coronary artery disease were excluded. They were divided into the insulin-resistant group (AVS+IR; N = 28) and no insulin-resistant group (AVS-IR; N = 29) according to the median value of homeostatic model assessment index. Computed tomography scans were also performed to measure the aortic valve calcium score and the visceral adipose tissue (VAT) area. In addition, age- and sex- adjusted 28 control subjects were recruited for the comparison. RESULTS: There were no significant differences in LV ejection fraction or mass index among the groups. The AVS+IR group had a higher aortic valve calcium score (median 94 versus 21, P = 0.022) and a larger VAT area (113 ± 42 cm(2) versus 77 ± 38 cm(2), P = 0.001) than the AVS-IR group. Notably, LV global longitudinal strain, strain rate (SR), and early diastolic SR were significantly lower in the AVS+IR group than in the AVS-IR group and in control subjects (strain: -16.2 ± 1.6% versus -17.2 ± 1.2% and -18.9 ± 0.8%; SR: -1.18 ± 0.26 s(-1) versus -1.32 ± 0.21 s(-1) and -1.52 ± 0.08 s(-1); early diastolic SR: -1.09 ± 0.23 s(-1) versus -1.23 ± 0.18 s(-1) and -1.35 ± 0.12 s(-1); P < 0.05 for all comparison), whereas circumferential function were not significantly different. Multiple linear regression analyses revealed insulin resistance as an independent determinant of LV longitudinal strain (P = 0.017), SR (P = 0.047), and early diastolic SR (P = 0.049) regardless of LV mass index or VAT area. CONCLUSIONS: Insulin resistance is a powerful independent predictor of subclinical LV dysfunction regardless of concomitant visceral obesity and LV hypertrophy. Thus, it may be a novel therapeutic target to prevent subsequent heart failure in patients with AVS
Asymmetry in the Mossbauer Spectra of Amorphous Fe_<100-x>B_x (14≤x≤21) Alloys
The Mossbauer spectra of amorphous Fe_B_x (14≤x≤21) alloys which are slightly asymmetric are analyzed in terms of the distributions of hyperfine fields and isomer shifts. On the assumption that the correlation between hyperfine fields H and isomer shifts I. S. is described by I. S.=c_0+c_1・H, where c_0 and c_1 are constants, the value of c_1 is dependent upon the concentration as same as c_0. While the change of c_0 is connected smoothly to the isomer shifts of crystalline α-Fe, Fe_2B and FeB, the value of c_1 which explains the asymmetry is sensitive to the amorphous structure
Neutron Irradiation Effects on Magnetic Properties of Some Heusler Alloys(Metallurgy)
The neutron irradiation effects were studied with measurements of temperature dependence of magnetization in ordered and disordered Heusler alloys. The irradiation was carried out in JMTR with a total flux of fast neutrons of 10^ nvt. Fully ordered Cu_2MnIn, partially ordered Cu_2MnAl and completely disordered Cu_2MnSn were prepared with various temperature treatments. The magnetization-temperature curves of each specimen were measured before and after irradiation. In the irradiated Cu_2MnIn, the disordering by the irradiation gave rise to a decrease of magnetization, and the temperature dependence of magnetization showed that the disordered region contained various regions with different degrees of disorder. For the distribution of the disordered region, the calculation based on the theory of temperature spike by Seitz and Koekler gave a feasible result that a disordered region comprised a central core with a radius of 5.4 A which was completely disordered and a periphery of 3.3 A thickness which was partially disordered. From the magnetization-temperature curves of Cu_2MnAl, it was considered that the disordered regions induced by the irradiation had different properties from those induced by the heat treatment. The former were the localized and comprised regions corresponding to various degrees of disorder, while the latter spread spatially in a wide range with a certain degree of disorder. The ordering by enhanced diffusion occurred simultaneously to an extent comparable to the disordering, and so it played an important role in the magnetization in the partially disordered Cu_2MnAl. In the disordered Cu_2MnSn, however, the ordering effect was very small. It is supposed to be difficult for the A2 structure to transform into the L2_1 structure by the enhanced diffusion
Association Between Visceral Adipose Tissue Area and Coronary Plaque Morphology Assessed by CT Angiography
ObjectivesWe sought to investigate the association between visceral adipose tissue (VAT) with the presence, extent, and characteristics of noncalcified coronary plaques (NCPs) using 64-slice computed tomography angiography (CTA).BackgroundAlthough visceral adiposity is associated with cardiovascular events, its association with NCP burden and vulnerability is not well known.MethodsThe study population consisted of 427 patients (age 67 ± 11 years; 63% men) with proven or suspected coronary artery disease who underwent 64-slice CTA. We assessed the presence and number of NCPs for each patient. The extent of NCP was tested for the difference between high (≥2) and low (≤1) counts. We further evaluated the vulnerable characteristics of NCPs with positive remodeling (remodeling index >1.05), low CT density (≤38 HU), and the presence of adjacent spotty calcium. Plain abdominal scans were also performed to measure the VAT and subcutaneous adipose tissue area.ResultsA total of 260 (61%) patients had identifiable NCPs. Multivariate analyses revealed that increased VAT area (per 1 standard deviation, 58 cm2) was significantly associated with both the presence (odds ratio [OR]: 1.68; 95% confidence interval [CI]: 1.28 to 2.22) and extent (OR: 1.31; 95% CI: 1.03 to 1.68) of NCP. Other body composition measures, including subcutaneous adipose tissue area, body mass index, and waist circumference were not significantly associated with either presence or extent of NCP. Increased VAT area was also independently associated with the presence of NCP with positive remodeling (OR: 1.71; 95% CI: 1.18 to 2.53), low CT density (OR: 1.69; 95% CI: 1.17 to 2.47), and adjacent spotty calcium (OR: 1.52; 95% CI: 1.03 to 2.27).ConclusionsIncreased VAT area was significantly associated with NCP burden and vulnerable characteristics identified by CTA. Our findings may explain the excessive cardiovascular risk in patients with visceral adiposity, and support the potential role of CTA to improve risk stratification in such patients
Odor Removal Characteristics of a Laminated Film-Electrode Packed-Bed Nonthermal Plasma Reactor
Odor control has gained importance for ensuring a comfortable living environment. In this paper, the authors report the experimental results of a study on the detailed characteristics of a laminated film-electrode and a laminated film-electrode packed-bed nonthermal plasma reactor, which are types of dielectric barrier discharge (DBD) reactor used for odor control. These plasma reactors can be potentially used for the decomposition of volatile organic compounds (VOCs) and reduction of NOx. The reactor is driven by a low-cost 60-Hz neon transformer. Removal efficiencies under various experimental conditions are studied. The complete decomposition of the main odor component, namely, NH3, is achieved in a dry environment. The retention times are investigated for the complete removal of NH3 in the case of the film-electrode plasma reactor and the film-electrode packed-bed plasma reactor. The removal efficiency of the former reactor is lower than that of the latter reactor. Mixing another odor component such as CH3CHO in the gas stream has no significant effect on NH3 removal efficiency
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