Fatigue Prediction of the Discharge Pipe in Reciprocating Compressor

In this paper, a fatigue prediction of the line discharge tube for reciprocating compressor being installed in a refrigerator was studied. The tube usually gets plenty of the repeated loads caused by the start and stop motion of a reciprocating compressor. There are two representative methods to predict the fatigue stress. At first the stress-life can be applied to the problem which takes a lot of repeated stress within the elastic strain range. Second is the strain-life method which can be used when it comes to the problem of a small repeated stress in the plastic strain range. This paper presents the stress-life method how the design parameters of a discharge pipe relate to the fatigue prediction and analyzes the co-relation between them

Vertical two-dimensional layered fused aromatic ladder structure

Planar two-dimensional (2D) layered materials such as graphene, metal-organic frameworks, and covalent-organic frameworks are attracting enormous interest in the scientific community because of their unique properties and potential applications. One common feature of these materials is that their building blocks (monomers) are flat and lie in planar 2D structures, with interlayer -pi stacking, parallel to the stacking direction. Due to layer-to-layer confinement, their segmental motion is very restricted, which affects their sorption/desorption kinetics when used as sorbent materials. Here, to minimize this confinement, a vertical 2D layered material was designed and synthesized, with a robust fused aromatic ladder (FAL) structure. Because of its unique structural nature, the vertical 2D layered FAL structure has excellent gas uptake performance under both low and high pressures, and also a high iodine (I-2) uptake capacity with unusually fast kinetics, the fastest among reported porous organic materials to date. Stacking of planar layers composed of flat building blocks in two dimensional materials results in restriction of segmental motion which affects their typical properties, such as sorption or desorption. Here, the authors minimize this confinement using a vertically-stacked fused aromatic ladder structure and demonstrate excellent gas uptake under low and high pressure

Effect of a heat treatment on the precipitation behavior and tensile properties of alloy 690 steam generator tubes

The intergranular carbide precipitation behavior and its effect on the tensile properties were investigated in alloy 690. The precipitation of intergranular carbides, identified as Cr-rich M23C6, was retarded on the low-angle grain boundaries and the coincidence-site lattice boundaries. The M23C6 carbides have a cube-cube orientation relationship with the matrix. The ultimate tensile strength, yield strength, and elongation of the solution annealed alloy 690 are 648.2 ± 8.2 MPa, 242.8 ± 10.5 MPa and 44.9 ± 2.3%, respectively. The ultimate tensile strength and the yield strength increased to 764.8 ± 7.8 MPa and 364.8 ± 10.2 MPa until the aging time reached 16 h. This increase is ascribed to the M23C6 carbide acting as reinforcements. However, when the aging time exceed 16 h, these properties gradually decreased with increasing aging time. The decrease in ultimate tensile strength, yield strength, and elongation were mainly caused by the intergranular cracking due to the low bond strength between the carbide and the matrix

Flash Pulmonary Edema in a Patient With Unilateral Renal Artery Stenosis and Bilateral Functioning Kidneys

Flash pulmonary edema typically exhibits sudden onset and resolves rapidly. It generally is associated with bilateral renal artery stenosis or unilateral stenosis in conjunction with a single functional kidney. We describe a patient who presented with flash pulmonary edema treated by percutaneous therapy with stent implantation. Our case is unique in that the flash pulmonary edema occurred in the setting of unilateral renal artery stenosis with bilateral functioning kidneys

Intravascular Ultrasound-Guided Troubleshooting in a Large Hematoma Treated With Fenestration Using a Cutting Balloon

Intramural hematoma formation is not a well-studied complication of percutaneous coronary intervention. We describe a patient with stable angina who developed an intramural hematoma during elective percutaneous coronary intervention (PCI) in the right coronary artery (RCA). Total occlusion with dense dye staining developed a long way from the distal RCA, near the posterior descending artery bifurcation site. The true lumen was compressed by the enlarged, tense, false lumen. The patient was successfully treating with intravascular ultrasound-guided fenestration using a cutting balloon, and a stent was implanted in the distal RCA

Correlation between Geometrically induced oxygen octahedral tilts and multiferroic behaviors in BiFeO3 films

The equilibrium position of atoms in a unit cell is directly connected to crystal functionalities, e.g., ferroelectricity, ferromagnetism, and piezoelectricity. The artificial tuning of the energy landscape can involve repositioning atoms as well as manipulating the functionalities of perovskites (ABO3), which are good model systems to test this legacy. Mechanical energy from external sources accommodating various clamping substrates is utilized to perturb the energy state of perovskite materials fabricated on the substrates and consequently change their functionalities; however, this approach yields undesired complex behaviors of perovskite crystals, such as lattice distortion, displacement of B atoms, and/or tilting of oxygen octahedra. Owing to complimentary collaborations between experimental and theoretical studies, the effects of both lattice distortion and displacement of B atoms are well understood so far, which leaves us a simple question: Can we exclusively control the positions of oxygen atoms in perovskites for functionality manipulation? Here the artificial manipulation of oxygen octahedral tilt angles within multiferroic BiFeO3 thin films using strong oxygen octahedral coupling with bottom SrRuO3 layers is reported, which opens up new possibilities of oxygen octahedral engineering

Gene-Environment Interactions Relevant to Estrogen and Risk of Breast Cancer: Can Gene-Environment Interactions Be Detected Only among Candidate SNPs from Genome-Wide Association Studies?

In this study we aim to examine gene–environment interactions (GxEs) between genes involved with estrogen metabolism and environmental factors related to estrogen exposure. GxE analyses were conducted with 1970 Korean breast cancer cases and 2052 controls in the case-control study, the Seoul Breast Cancer Study (SEBCS). A total of 11,555 SNPs from the 137 candidate genes were included in the GxE analyses with eight established environmental factors. A replication test was conducted by using an independent population from the Breast Cancer Association Consortium (BCAC), with 62,485 Europeans and 9047 Asians. The GxE tests were performed by using two-step methods in GxEScan software. Two interactions were found in the SEBCS. The first interaction was shown between rs13035764 of NCOA1 and age at menarche in the GE|2df model (p-2df = 1.2 × 10−3). The age at menarche before 14 years old was associated with the high risk of breast cancer, and the risk was higher when subjects had homozygous minor allele G. The second GxE was shown between rs851998 near ESR1 and height in the GE|2df model (p-2df = 1.1 × 10−4). Height taller than 160 cm was associated with a high risk of breast cancer, and the risk increased when the minor allele was added. The findings were not replicated in the BCAC. These results would suggest specificity in Koreans for breast cancer risk