Measurements of Thermodynamic Properties for R1123 and R1123+R32 Mixture

Measurements of PrT and PrTx properties, vapor pressures, saturated densities were carried out for a new low GWP refrigerant R1123(trifluoroethylene; CF2=CHF) and its binary mixture of R1123 + R32 system.  Sixty-three PrT property data and 13 vapor-pressure data for R1123 were obtained in the temperatures between 300 K and 430 K, pressures up to 6.9 MPa, and densities between 100 and 900 kg/m3 along 7 isochores. For the saturated densities for R1123, 21 data were obtained in the temperatures between 316.32 K and 331.73 K and densities between 222 and 880 kg/m3 . On the basis of these measurements, the correlation of vapor pressures was also proposed, Moreover the critical parameters for R1123 were determined as Tc = 331.73 K, rc = 504 kg/m3 , and Pc = 4546 kPa. As for the binary R1123 + R32 mixture, the same kinds of measurements were carried out for the 40 mass% R1123 mixture and 60 mass% R1123 mixture. The composition dependence of the critical parameters for this mixture are also discussed

A Thermodynamic Property Model for the R-134a/245fa Mixture

A thermodynamic property model explicit in the Helmholtz energy is presented for the R-134a/245fa mixture. Although some manufacturers have already produced heat pump systems using the mixture, an accurate property model has not been established for the mixture. The model presented in this work can be used to detailed and comprehensive analysis of the heat pumps. The multi-fluid approximation based on pure-fluid Helmholtz energy equations of state forms the framework of the model. The Helmholtz energy of the mixture is expressed as the sum of the ideal gas contribution, the compressibility contribution (real fluid contribution), and the contribution from mixing to represent the deviation from ideal mixtures. The first two contributions are calculated using the most accurate equations of state for R-134a and R-245fa. The independent variables are the temperature, molar volume, and composition. Typical multi-fluid models include five adjustable parameters, which are normally optimized by a nonlinear fitting to experimental data. The fitting in this work determines the parameters using experimental data for the critical parameters and liquid and vapor densities obtained in our previous work, in addition to published vapor-liquid equilibrium data. The numerical data of the critical parameters and densities are also presented. The model can be used to calculate all thermodynamic properties of the mixture at various compositions. The estimated uncertainties in calculated properties from the model are within ±0.5 % for the bubble and dew point pressures and ±0.3 % for the liquid and vapor densities. The critical locus of the mixture is accurately represented with the model. The calculated critical temperature corresponds to experimental values within ±0.3 K

Surface Tension Measurement of Low GWP Refrigerant Mixture HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32

HFOs (hydro-fluoro-olefins), HFO-1123 and HFO-1234ze(E) with GWP (global warming potential) of less than 1 attracted attention in a field of air conditioning and refrigeration engineering. However, the use of those HFO alone in such heat pump systems lucks adequate capacity or chemical stability. To compensate the shortcomings, mixtures coupled with R32 is considered to be one solution. This paper presents the surface tension measurement data of HFC-32, HFO-1123, and HFO-1234ze(E), and also their binary mixtures HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32 at various mass fractions. The capillary constant and surface tension of those are measured across temperature range from 267 K to 307 K using a measuring apparatus based on the differential capillary rise method to discuss the effects of mass fraction to the surface tension of HFO-1123/HFC-32 and HFO-1234ze(E)/HFC-32. The propagated uncertainty in the surface tension is typically 0.3 mN m-1. The experimentally quantified surface tension of HFC-32 alone well agrees with the calculated value of REFPROP ver. 9.1, and also data in literatures. However, data of HFO-1234ze(E) showed slightly negative deviation to REFPROP. To the authors’ best knowledge, available data for HFO-1123 was not found and presented data are new, so far. Among the selected predicting methods, the correlations of Di Nicola et al. (2011) and Gharagheizi et al. (2012) show the best agreement with data of two HFOs. The measured surface tension data of HFO-1123/HFC-32 at a HFC-32 mass fraction of 0.48 well agree with the correlation of Di Nicola et al. (2017). However, the correlation deviates from the present data as mass fraction approaches to 0 and 1. Similarly, data of HFO-1234ze(E)/HFC-32 shows considerable deviations

Performance Evaluation of Heat Pump Cycle using Low GWP Refrigerant Mixtures of HFC-32 and HFO-1123

Hydro-fluorocarbons (HFCs) have been widely used as working fluids (refrigerants) in air-conditioning and refrigeration systems. At the 1997 Kyoto Conference (COP3), a worldwide agreement was obtained to regulate the production and use of HFCs exhibit high global warming potential (GWP). In the above situation, Hydro-fluoro Olefins (HFOs) having extremely low GWP values such as HFO-1234yf, HFO-1234ze(E), HFO-1123, has attracted attentions. In this study, the performance of heat pump cycle using low GWP refrigerant mixtures of HFC-32 and HFO-1123 is evaluated experimentally. The experimental system is a water heat source vapor compression cycle, mainly composed of an inverter-controlled & hermetic-type scroll compressor (cylinder volume: 11 cm3), an oil separator, a double-tube-type condenser (heat transfer tube; inner grooved , OD 9.53 mm, ID 7.53 mm, total length 7.2 m), a liquid receiver, a solenoid expansion valve, and a double-tube-type evaporator (heat transfer tube; inner grooved , OD 9.53 mm, ID 7.53 mm, total length 7.2 m). Tested compositions of mixtures of HFO-32/HFO-1123 are 58/42 mass% (GWP=393) and 42/58 mass% (GWP=285). These mixtures are tested for the heating and the cooling modes. In the heating mode, the heat sink water temperatures at the inlet and outlet of condenser are kept at 20 ˚C and 45 ˚C, respectively, and the heat source water temperatures at the inlet and outlet of evaporator are kept at 15 ˚C and 9 ˚C. Then, the heating load is varied from 1.6 kW to 2.6 kW. Similarly, in the cooling mode, the water temperature at the inlet and outlet are kept at 30 ˚C and 45 ˚C in condenser, and at 20 ˚C and 10 ˚C in evaporator. Then, the cooling load is varied from 1.4 kW to 2.4 kW. The conventional refrigerant R410A is also tested as the reference. In both modes of heating and cooling, the COP of HFO-32/HFO-1123 mixture (58/42 mass%) is almost the same as that of R410A, while the COP of HFO-32/HFO-1123 mixture (42/58 mass%) is a little lower than that of R410A. By analyzing the irreversible loss of the heat pump cycle based on the second low analysis, the losses of both mixtures in condenser and evaporator are slightly smaller than that of R410A, while the losses of both mixtures in compressor are slightly higher than that of R410A. This result reveals that tested mixtures of HFO-32/HFO-1123 are available to use as the alternative of R410A if the design of compressor and heat exchangers are optimized

Two-Phase and Vapor-Phase Thermophysical Property (pvTz) Measurements of the Difluoromethane + trans-1,3,3,3-Tetrafluoroprop-1-ene Binary System

In this paper, 182 pvTz data (28 data in the two-phase region and 154 data in the superheated vapor region) of mixtures containing difluoromethane (R32) and trans-1,3,3,3-tetrafluoroprop-1-ene (R12..

Surface Tension and Parachor Measurement of Low-Global Warming Potential Working Fluid cis-1-Chloro-2,3,3,3-tetrafluoropropene (R1224yd(Z))

This article presents the accurate surface tension measurement of cis-1-chloro-2,3,3,3-tetrafluoropropene (R1224yd(Z), (Z)–CF3CF═CHCl), over the temperature range 266–340 K. The measurement was performed using the differential capillary rise. The expanded uncertainty at 95% confidence was estimated to be within 0.19 mN·m–1. Based on the measured data, the van der Waals-type correlation expressing the temperature dependence was obtained as σ = 57.02 (1 – T/428.69)1.265 [mN·m–1]. In addition, the parachor [PR1224yd(Z)] was determined as 207. The surface tension values predicted by Miller and Thodos (Ind. Eng. Chem. Fund.,1963,2.1, 78), Miqueu et al. (Fluid Ph. Equilibria,2000,172, 169), and Di Nicola et al. (Int. J. Thermophys.,2011,34, 2243), as well as those obtained using the parachor method, were in good agreement with the measurement data

MUC4 and MUC1 expression in adenocarcinoma of the stomach correlates with vessel invasion and lymph node metastasis: an immunohistochemical study of early gastric cancer.

We have previously reported that MUC4 expression is a poor prognostic factor in various carcinomas. Our previous study also showed that MUC1 expression in gastric cancers, including the early and advanced stages is a poor prognostic factor. In the present study, the expression profiles of MUC4 and MUC1 were examined by immunohistochemistry (IHC) using two anti-MUC4 monoclonal antibodies (MAbs), 8G7 and 1G8, and anti-MUC1 MAb DF3 in 104 gastrectomy specimens of early gastric adenocarcinoma with submucosal invasion (pT1b2), including 197 histological subtype lesions. Before the IHC study of the human specimens, we evaluated the specificity of the two MAbs by Western blotting and IHC of two MUC4 mRNA expressing gastric cancer cell lines. MAb 8G7 reacted clearly, whereas MAb 1G8 did not show any reactivity, in either Western blotting or IHC. In the IHC of the gastric cancers, the expression rates of MUC4/8G7 detected by MAb 8G7, MUC4/1G8 detected by MAb 1G8 and MUC1/DF3 detected by MAb DF3 in well differentiated types (70%, 38/54; 67%, 36/54; 52%, 28/54) were significantly higher than those in poorly differentiated types (18%, 10/55; 36%, 20/55; 13%, 7/55) (

CANGAROO-III Search for Gamma Rays from SN 1987A and the Surrounding Field

Optical images of SN 1987A show a triple ring structure. The inner (dust) ring has recently increased in brightness and in the number of hot spots suggesting that the supernova shock wave has collided with the dense pre-existing circumstellar medium, a scenario supported by radio and X-ray observations. Such a shocked environment is widely expected to result in the acceleration of charged particles, and the accompanying emission of very high energy gamma-rays. Here, we report the results of observations made in 2004 and 2006 which yield upper limits on the TeV gamma-ray flux, which are compared with a theoretical prediction. In addition, we set upper limits on the TeV flux for four high energy objects which are located within the same field of view of the observation: the super-bubble 30 Dor C, the Crab-like pulsar PSR B0540$-$69, the X-ray binary LMC X-1, and the supernova remnant N157B.Comment: 5 pages, 5 figures, Accepted for publication in Ap

Adenomyoma of the Ileum Leading to Intussusception

Adenomyoma of the ileum is a rare condition. A 68-year-old Japanese man presented with nausea and distension of the abdomen. Enhanced computed tomography of his abdomen revealed wall thickening in the ileum and dilation of the proximal small intestine. Open laparotomy was performed to find the cause of the patient's small bowel obstruction, and a tumor was found in the ileum, which had resulted in intussusception. The tumor and 20 cm of the adjacent ileum were resected. The resected specimen displayed a macroscopic appearance suggestive of a submucosal tumor. Histopathological evaluation showed duct cell proliferation and bundles of smooth muscle cells from the mucosa to the serosa, leading to a diagnosis of adenomyoma. Immunohistochemical examination found that cytokeratin 7 and carbohydrate antigen 19-9 were expressed in the duct epithelia. We report a rare case of ileal adenomyoma leading to intussusception in an adult and present the immunohistochemical evaluation of the adenomyoma