No abstract

In order to explore the fracture mechanism of jointed Phyllite, the TAJW-2000 rock mechanics test system is used to carry out uniaxial compression tests on different joint inclination Phyllites. The influence of joint inclination of Phyllite failure mode is discussed, and the progressive failure process of Phyllite is studied. The test results show that the uniaxial compressive strength anisotropy of jointed Phyllite is remarkable. As the inclination increases, it exhibits a U-shaped change; When 30° ≤ α ≤ 75°, the tensile and shear failures along the joint inclination mainly occurs. the joint inclination controls the failure surface form of the Phyllite; The crack initial stress level of the joint Phyllite is 0.30–0.59σf, the crack failure stress level is 0.44–0.86σf. When α = 90°, the σcd value is the largest, and σcd with α = 90° can be used as the maximum reliable value of uniaxial compressive strength of Phyllite. Using the theory of fracture mechanics, it is analyzed that under uniaxial compression of the rock, the crack does not break along the original crack direction, but extends along the direction at a certain angle to the original crack. The joint effect coefficient is proposed to show the influence of the joint inclination on the uniaxial compressive strength of the phyllite. Both the test and simulation results show that when the joint inclination is 60°, the joint effect coefficient is the largest. The compressive strength is the smallest. Numerical simulation analyses the crack evolution law of phyllite under different joint inclination under uniaxial compression, which verifies that there are different failure modes of joint phyllite under uniaxial compression.

Background: Hypertension is a major factor associated with heart failure (HF).While effective blood pressure (BP) control is recommended in patients with HF, little is known regarding treatment and control rates in these patients. Methods: The analyses assessed HF patients from 195 hospitals participating in the GWTG-HF quality improvement program from January 2005 through September 2006. Patients with hypertension were assessed for number and type of hypertension treatment as well as BP control rates. Analyses were stratified by race-sex groups with multivariate logistic regression models using the generalized estimating equations methods assessed the factors associated with multiple treatment, type of therapy, and BP control levels. Results: Of 37,318 HF patients, 62.3% (23,257) had diagnosed hypertension. The majority (67.3%) of these high-risk individuals were treated with 3 or more hypertension drugs, which was significantly varied by race-sex groups. The use of ACEI (64.6%), beta blockers (79.9%), angiotensin receptor blockers (18.5%), diuretics (62.4%), loop diuretic (73.8%), and calcium channel blockers (13.3%) significantly varied by race-sex groups. BP control rates (< 140/90 mm Hg) at discharge significantly varied by race-sex group (total 70.8%; white males (WM) 76.3%; white females (WF) 71.1%; black males (BM) 63.0%; and black females (BF) 62.9%). Significant factors associated with BP control at discharge included age, race-sex (WF vs. BF, WM vs. BF), atrial fibrillation, hyperlipidemia, coronary heart disease, ICD, pacemaker, history of MI, and not having one or more of the following co-morbid conditions: diabetes, peripheral vascular disease, CVA and renal disease. Control rates considering BP < 130/80 mm Hg (52.3%) showed similar significant variation by race-sex group (WM 57.4%; WF 53.7%; BM 42.3%.; and BF 44.4%). Conclusions: The less than optimal blood pressure control levels and the gender/racial disparities support continued emphasis on hypertension treatment and control among patients with heart failure.