The S shape of a granular pile in a rotating drum

The shape of a granular pile in a rotating drum is investigated. Using Discrete Elements Method (DEM) simulations we show that the "S shape" obtained for high rotation speed can be accounted for by the friction on the end plates. A theoretical model which accounts for the effect of the end plates is presented and the equation of the shape of the free surface is derived. The model reveals a dimensionless number which quantifies the influence of the end plates on the shape of the pile. Finally, the scaling laws of the system are discussed and numerical results support our conclusions

Insights into the music patterns of St Basil liturgy according to the Coptic rite

The exact roots of Coptic music and its creation remain unknown, with speculations suggesting potential Pharaonic, Jewish and Greek roots. This thesis focuses on the musical features of both the priest’s chants and the congregational responses in the St Basil liturgy according to the Coptic rite, in an attempt to discern its patterns and roots since it seems impossible to identify its composers and origin. The practice-based empirical methods used were audio and video recording of the liturgy, notating its music using the Arabic music rules, comparing melodies of Greek responses practised in the Byzantine and Coptic traditions and attempting to reproduce the Coptic melodies using Pharaonic nay replicas. The current literature shows no description of musical features and scales of St Basil liturgy, as stated decades ago by H Hickmann, being transmitted via the oral tradition. Audio analysis of some of the liturgical responses revealed significant scale discrepancies between three renowned contemporary musicians. Also, having compared four sets of notations by eminent Coptic musicians, there were significant differences in the style of notation and the dominating scales. These results raised doubt about the accuracy of the conventional Arabic music analyses in describing the Coptic music, since scale recognition is based only on the tetrachord. Despite that, my suggestion of the seven musical sections of the liturgy has been confirmed. Also, comparing the music of thirteen Greek responses shared between the Byzantine and Coptic traditions, showed similarities only between two; the rest of the responses were different. Furthermore, attempts to reproduce the St Basil melodies using Pharaonic nay (flute) replicas showed limited ability of the oldest long nays compared to the more recent short ones. Thus, despite being the first empirical study of the music features of St Basil liturgy according to the Coptic rite, this thesis successfully describes unique patterns and puts forward suggestions, with some speculations, regarding the roots of such ancient music, which requires further analysis

Effects of communication and utility-based decision making in a simple model of evacuation

We present a simple cellular automaton based model of decision making during evacuation. Evacuees have to choose between two different exit routes, resulting in a strategic decision making problem. Agents take their decisions based on utility functions, these can be revised as the evacuation proceeds, leading to complex interaction between individuals and to jamming transitions. The model also includes the possibility to communicate and exchange information with distant agents, information received may affect the decision of agents. We show that under a wider range of evacuation scenarios performance of the model system as a whole is optimal at an intermediate fraction of evacuees with access to communication.Comment: 9 pages, 9 figure

Materials Research in Microgravity 2012

Reducing gravitational effects such as thermal and solutal buoyancy enables investigation of a large range of different phenomena in materials science. The Symposium on Materials Research in Microgravity involved 6 sessions composed of 39 presentations and 14 posters with contributions from more than 14 countries. The sessions concentrated on four different categories of topics related to ongoing reduced-gravity research. Highlights from this symposium will be featured in the September 2012 issue of JOM. The TMS Materials Processing and Manufacturing Division, Process Technology and Modeling Committee and Solidification Committee sponsored the symposium

Cardiopulmonary assessment of patients with systemic sclerosis for hematopoietic stem cell transplantation: recommendations from the European Society for Blood and Marrow Transplantation Autoimmune Diseases Working Party and collaborating partners.

Systemic sclerosis (SSc) is a rare disabling autoimmune disease with a similar mortality to many cancers. Two randomized controlled trials of autologous hematopoietic stem cell transplantation (AHSCT) for SSc have shown significant improvement in organ function, quality of life and long-term survival compared to standard therapy. However, transplant-related mortality (TRM) ranged from 3-10% in patients undergoing HSCT. In SSc, the main cause of non-transplant and TRM is cardiac related. We therefore updated the previously published guidelines for cardiac evaluation, which should be performed in dedicated centers with expertize in HSCT for SSc. The current recommendations are based on pre-transplant cardiopulmonary evaluations combining pulmonary function tests, echocardiography, cardiac magnetic resonance imaging and invasive hemodynamic testing, initiated at Northwestern University (Chicago) and subsequently discussed and endorsed within the EBMT ADWP in 2016

A Review of the Effect of Diet on Cardiovascular Calcification

Abstract: Cardiovascular (CV) calcification is known as sub-clinical atherosclerosis and is recognised as a predictor of CV events and mortality. As yet there is no treatment for CV calcification and conventional CV risk factors are not consistently correlated, leaving clinicians uncertain as to optimum management for these patients. For this reason, a review of studies investigating diet and serum levels of macro-and micronutrients was carried out. Although there were few human studies of macronutrients, nevertheless transfats and simple sugars should be avoided, while long chain ω-3 fats from oily fish may be protective. Among the micronutrients, an intake of 800 μg/day calcium was beneficial in those without renal disease or hyperparathyroidism, while inorganic phosphorus from food preservatives and colas may induce calcification. A high intake of magnesium (≥380 mg/day) and phylloquinone (500 μg/day) proved protective, as did a serum 25(OH)D concentration of ≥75 nmol/L. Although oxidative damage appears to be a cause of CV calcification, the antioxidant vitamins proved to be largely ineffective, while supplementation of α-tocopherol may induce calcification. Nevertheless other antioxidant compounds (epigallocatechin gallate from green tea and resveratrol from red wine) were protective. Finally, a homocysteine concentration >12 µmol/L was predictive of CV calcification, although a plasma folate concentration of >39.4 nmol/L could both lower homocysteine and protect against calcification. In terms of a dietary programme, these recommendations indicate avoiding sugar and the transfats and preservatives found in processed foods and drinks and adopting a diet high in oily fish and vegetables. The micronutrients magnesium and vitamin K may be worthy of further investigation as a treatment option for CV calcification

Evaluation of Left Atrial Size and Function: Relevance for Clinical Practice

Left atrial (LA) structural and functional evaluation have recently emerged as powerful biomarkers for adverse events in a variety of cardiovascular conditions. Moreover, noninvasive evaluation of LA pressure has gained importance in the characterization of the hemodynamic profile of patients. This review describes the methodology, benefits and pitfalls of measuring LA size and function by echocardiography and provides a brief overview of the prognostic utility of newer echocardiographic metrics of LA geometry and function (i.e., three-dimensional volumes, longitudinal strain, and phasic function parameters)

Gravity insensitive flexure pivots for watch oscillators

Classical pivots have frictional losses leading to the limited quality factor of oscillators used as time bases in mechanical watches. Flexure pivots address these issues by greatly reducing friction. However, they have drawbacks such as gravity sensitivity and limited angular stroke. This paper analyses these problems for the cross-spring flexure pivot and presents an improved version addressing these issues. We first show that the cross spring pivot cannot be both insensitive to gravity and have a long stroke. A 10 ppm sensitivity to gravity acceptable for watchmaking applications occurs only when the leaf springs cross at about 87.3 % of their length, but the stroke is only 30.88 % of the stroke of the symmetrical cross-spring pivot. For the symmetrical pivot, gravity sensitivity is of the order of 104 ppm. Our solution is to introduce the co-differential concept which we show to be gravity insensitive. We then use the co-differential to build a gravity insensitive flexure pivot with long stroke. The design consists of a main rigid body, two co-differentials and a torsional beam. We show that our pivot is gravity insensitive and achieves 100 % of the stroke of symmetrical pivots

Tricuspid Regurgitation Velocity and Mean Pressure Gradient for the Prediction of Pulmonary Hypertension According to the New Hemodynamic Definition

Background: The hemodynamic definition of PH has recently been revised with unchanged threshold of peak tricuspid regurgitation velocity (TRV). The aim of this study was to evaluate the predictive accuracy of peak TRV for PH based on the new (>20 mmHg) and the old (>25 mmHg) cut-off value for mean pulmonary artery pressure (mPAP) and to compare it with the mean right ventricular–right atrial (RV–RA) pressure gradient. Methods: Patients with advanced heart failure were screened from 2016 to 2021. The exclusion criteria were absent right heart catheterization (RHC) results, chronic obstructive pulmonary disease, any septal defect, inadequate acoustic window or undetectable TR. The mean RV–RA gradient was calculated from the velocity–time integral of TR. Results: The study included 41 patients; 34 (82.9%) had mPAP > 20 mmHg and 24 (58.5%) had mPAP > 25 mmHg. The AUC for the prediction of PH with mPAP > 20 mmHg was 0.855 for peak TRV and mean RV–RA gradient was 0.811. AUC for the prediction of PH defined as mPAP > 25 mmHg for peak TRV was 0.860 and for mean RV–RA gradient was 0.830. A cutoff value of 2.4 m/s for peak TRV had 65% sensitivity and 100% positive predictive value for predicting PH according to the new definition. Conclusions: Peak TRV performed better than mean RV–RA pressure gradient in predicting PH irrespective of hemodynamic definitions. Peak TRV performed similarly with the two definitions of PH, but a lower cutoff value had higher sensitivity and equal positive predictive value for PH

Characterization of HAZ of API X70 Microalloyed Steel Welded by Cold-wire Tandem Submerged Arc Welding.

High strength low carbon microalloyed steels may be adversely affected by the high heat input and thermal cycle that they experience during tandem submerged arc welding (TSAW). The heat affected zone (HAZ), particularly the coarse grained heat affected zone (CGHAZ), i.e., the region adjacent to the fusion line, has been known to show lower fracture toughness compared with the rest of the steel. The deterioration in toughness of the CGHAZ is attributed to the formation of martensite-austenite (M-A) constituents, local brittle zones (LBZ) and large prior austenite grains (PAG). In the present work, the influence of the addition of a cold wire at various wire feed rates in cold-wire tandem submerged arc welding (CWTSAW), a recently developed welding process for pipeline manufacturing, on the microstructure and mechanical properties of the HAZ of a microalloyed steel has been studied. The cold wire moderates the heat input of welding by consuming the heat of the trail electrode. Macrostructural analysis showed a decrease in the CGHAZ size by addition of a cold wire. Microstructural evaluation, using both tint etching optical microscopy (TEOM) and scanning electron microscopy (SEM), indicated the formation of finer PAGs and less fraction of M-A constituents with refined morphology within the CGHAZ when the cold wire was fed at 25.4 cm/min. This resulted in an improvement in the HAZ impact fracture toughness. These improvements are attributed to lower actual heat introduced to the weldment and lower peak temperature in the CGHAZ by cold wire addition. However, a faster feed rate of the cold wire at 76.2 cm/min adversely affected the toughness due to the formation of slender M-A constituents caused by the relatively faster cooling rate in the CGHAZ