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Cement-free concrete has a superior physical performance, such as in its strength and durability, compared to OPC concrete; however, it has the disadvantage of large shrinkage. Large shrinkage can cause cracks due to shrinkage stress in the long term. In this study, a shrinkage reducing agent (SRA) was used to reduce the shrinkage of cement-free mortar; its content was increased from 0.0 to 1.5%. For an SRA content of 1.0%, a calcium sulfoaluminate (CSA) expansive additive (EA) (2.5, 5.0, and 7.5%) was added. To calculate the shrinkage stress of cement-free mortar using the SRA and EA, the compressive strength, elastic modulus, and total and autogenous shrinkage were measured. The unit shrinkage stress of cement-free mortar was obtained by multiplying the elastic modulus by the length change and accumulated to obtain the shrinkage stress acting on the mortar according to the age. The shrinkage stress of cement-free mortar showed different tendencies as the age increased. At early ages, the shrinkage rate of the mortar occupied a large proportion of the shrinkage stress. In the long term, the shrinkage stress was significantly affected by the elastic modulus. As a result, SRA was found to be effective in reducing the shrinkage stress by decreasing both the elastic modulus and shrinkage. However, EA increased the shrinkage stress over the long term due to an increase in the elastic modulus even though it compensated for early-ages shrinkage. [ABSTRACT FROM AUTHOR]

Micro heat exchangers have been widely used in both of academic and industrial fields for controlling heat for decades. Especially, the printed circuit heat exchanger (PCHE) is applicable to high pressure and high temperature cases since the manufacturing process, diffusion bonding, gives high durability. However, flow does not occur uniformly in multiple channels, which causes a heat transfer difference between the channels that reduces the effectiveness of the system. Also, it makes the total pressure drop larger than when it is uniformly distributed. Flow distribution has been studied intensively for decades, but the mechanism has not been clarified yet, since flow in the header is much too complicated. As a step to reveal the mechanism, we focus on maldistribution and quantitatively investigate the phenomena. We prepared experimental devices, including a set of parallel micro-channels, inlet and outlet. We used water as a working fluid, and water soluble red ink for visualization. We measured the interface location to derive the flow speed at each channel. We focused on the dependency of channel length and flow speed. In the theoretical part, we derived the flow speed profile of the entire channels that shows good agreement with the experimental results. This study provides a theoretical basis on resolving the maldistribution problem. [ABSTRACT FROM AUTHOR]

The low GWP refrigerants attract a great attention due to various regulations such as Montreal protocol amendment and F-gas regulation. The amendment of Montreal protocol proposes to reduce the HFCs consumption by 85% until 2035 and F-gas legislation will reduce the HFCs consumption by 79% until 2030. In 2010, US DOE launched the low GWP refrigerant project which covers the lifecycle climate performance modeling, experimental evaluation and field testing. In 2015, Korea launched the project to develop the core technology of refrigeration system for low GWP (100) refrigerants application. Since the project limited the GWP value less than 100, the applicable candidates (except for natural working fluids) are restricted about five refrigerants including R-1234yf, R-1234ze-(E), R444A, R-1233zd(E) and R-1336mzz. In the literature, to the best of the author's knowledge, there is very limited information for pool boiling studies except R-1234yf. In present work, the cycle simulation and the prediction of pool boiling heat transfer coefficient for each refrigerant has been conducted. And the literature review of pool boiling for the refrigerants has been performed. [ABSTRACT FROM AUTHOR]

Purpose: We investigated whether I whole-body scintigraphy could predict functional changes in salivary glands after radioiodine therapy. Methods: We evaluated 90 patients who received initial high-dose (≥3.7 GBq) radioiodine therapy after total thyroidectomy. All patients underwent diagnostic (DWS) and post-ablation (TWS) I whole-body scintigraphy. Visual assessment of salivary radioiodine retention on DWS and TWS was used to divide the patients into two types of groups: a DWS+ or DWS- group and a TWS+ or TWS- group. Salivary gland scintigraphy was also performed before DWS and at the first follow-up visit. Peak uptake and %washout were calculated in ROIs of each gland. Functional changes (Δuptake or Δwashout) of salivary glands after radioiodine therapy were compared between the two groups. Results: Both peak uptake and the %washout of the parotid glands were significantly lower after radioiodine therapy (all p values <0.001), whereas only the %washout were significantly reduced in the submandibular glands (all p values <0.05). For the parotid glands, the TWS+ group showed larger Δuptake and Δwashout after radioiodine therapy than did the TWS- group (all p values <0.01). In contrast, the Δuptake and Δwashout of the submandibular glands did not significantly differ between the TWS+ and TWS- groups (all p values >0.05). Likewise, no differences in Δuptake or Δwashout were apparent between the DWS+ and DWS- groups in either the parotid or submandibular glands (all p values >0.05). Conclusion: Salivary gland radioiodine retention on post-ablation I scintigraphy is a good predictor of functional impairment of the parotid glands after high-dose radioiodine therapy. [ABSTRACT FROM AUTHOR]

Abstract: The worldwide issue of greenhouse gas reduction has recently drawn great attention to carbon capture and storage (CCS). Almost CCS studies have been focused in the capture technology of carbon dioxide and the geological investigation for underground storage. The study of mechanical injection system for carbon dioxide has not implemented nearly. We are intended to develop a ground system for underground injection of carbon dioxide. In this study, we made lab-scale underground injection system and implemented injection simulation test experimentally. The 10,000 ton/year pilot plant for geological storage of carbon dioxide will be designed on the base of these test results. Major components of the lab-scale underground injection system include a pressure pump and an in-line heater to bring liquid carbon dioxide into its supercritical state. Test results assure that this system readily achieves the designed injection pressure and temperature, showing satisfactory control performance. [Copyright &y& Elsevier]

Purpose: Bone metastasis is an important factor for the treatment and prognosis of breast cancer patients. Whole-body bone scintigraphy (WBBS) can evaluate skeletal metastases, and F-FDG PET/CT seems to exhibit high specificity and accuracy in detecting bone metastases. However, there is a limitation of F-FDG PET in assessing sclerotic bone metastases because some lesions may be undetectable. Recent studies showed that F-fluoride PET/CT is more sensitive than WBBS in detecting bone metastases. This study aims to evaluate the usefulness of F-fluoride PET/CT by comparing it with WBBS and F-FDG PET/CT in breast cancer patients with osteosclerotic skeletal metastases. Materials and Methods: Nine breast cancer patients with suspected bone metastases (9 females; mean age ± SD, 55.6 ± 10.0 years) underwent Tc-MDP WBBS, F-FDG PET/CT and F-fluoride PET/CT. Lesion-based analysis of five regions of the skeletons (skull, vertebral column, thoracic cage, pelvic bones and long bones of extremities) and patient-based analysis were performed. Results: F-fluoride PET/CT, F-FDG PET/CT and WBBS detected 49, 20 and 25 true metastases, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of F-fluoride PET/CT were 94.2 %, 46.3 %, 57.7 % and 91.2 %, respectively. Most true metastatic lesions on F-fluoride PET/CT had osteosclerotic change (45/49, 91.8 %), and only four lesions showed osteolytic change. Most lesions on F-FDG PET/CT also demonstrated osteosclerotic change (17/20, 85.0 %) with three osteolytic lesions. All true metastatic lesions detected on WBBS and F-FDG PET/CT were identified on F-fluoride PET/CT. Conclusion: F-fluoride PET/CT is superior to WBBS or F-FDG PET/CT in detecting osteosclerotic metastatic lesions. F-fluoride PET/CT might be useful in evaluating osteosclerotic metastases in breast cancer patients. [ABSTRACT FROM AUTHOR]