Trees of nuclei and bounds on the number of triangulations of the 3-ball

Based on the work of Durhuus-J{\'o}nsson and Benedetti-Ziegler, we revisit the question of the number of triangulations of the 3-ball. We introduce a notion of nucleus (a triangulation of the 3-ball without internal nodes, and with each internal face having at most 1 external edge). We show that every triangulation can be built from trees of nuclei. This leads to a new reformulation of Gromov's question: We show that if the number of rooted nuclei with $t$ tetrahedra has a bound of the form $C^t$, then the number of rooted triangulations with $t$ tetrahedra is bounded by $C_*^t$

CIRRHOTIC CARDIOMYOPATHY IN EGYPTIAN PATIENTS

Background: Liver  cirrhosis is   a health care problem in  Egypt  caused  by the high prevalence of  hepatitis C virus (HCV)  infection that affects 15-20 % of the population  . Cirrhotic cardiomyopathy is the term used to describe a constellation of features indicative of abnormal heart structure and function in patients with cirrhosis. Aim of this study is to assess the pattern and the extent of cardiac affection in cirrhotic patients and its relation to the presence or absence of ascites. Materials  and methods: This study was carried out on 70 patients with liver cirrhosis and 30 healthy controls. All persons were subjected to careful history & physical examination, laboratory investigations, abdominal ultrasonography ,and echocardiography. Results:   left ventricle end diastolic diameter was significantly  increased in cirrhotic patients with  ascites (5.40±0.58)  and without ascites ((5.31±0.51), compared to the control group (4.52±0.58) (p<0.05), . left ventricle end systolic diameter was      increased in cirrhotic patients with  ascites (3.57±2.2)  and without ascites (3.46±3.1), without ascites (3.18±2.5)but the difference was statistically non significant    (p > 0.05).   Left atrium diameter & Right ventricular end diastolic diameter were significantly increased in cirrhotic patients compared to the control group (p<0.05  The  pulmonary artery pressure  was elevated in cirrhotic patients compared to the control group .. Conclusion:  In the present study ptient with Liver cirrhosis were  associated with significant enlargement of cardiac chambers and diastolic dysfunction compared to the control group specially   in  the presence of ascites.Â

Decay of Correlations in a Topological Glass

In this paper we continue the study of a topological glassy system. The state space of the model is given by all triangulations of a sphere with $N$ nodes, half of which are red and half are blue. Red nodes want to have 5 neighbors while blue ones want 7. Energies of nodes with other numbers of neighbors are supposed to be positive. The dynamics is that of flipping the diagonal between two adjacent triangles, with a temperature dependent probability. We consider the system at very low temperatures. We concentrate on several new aspects of this model: Starting from a detailed description of the stationary state, we conclude that pairs of defects (nodes with the "wrong" degree) move with very high mobility along 1-dimensional paths. As they wander around, they encounter single defects, which they then move "sideways" with a geometrically defined probability. This induces a diffusive motion of the single defects. If they meet, they annihilate, lowering the energy of the system. We both estimate the decay of energy to equilibrium, as well as the correlations. In particular, we find a decay like $t^{-0.4}$

PVP2005-71322 INTRODUCTION OF THE ELEMENT INTERACTION TECHNIQUE FOR WELDING ANALYSIS AND SIMULATION

ABSTRACT The residual stresses generated due to welding in pressure components may have several harmful effects such as decrease in the resistance to cycling load and corrosive environments. The analysis of the welding process has been developed extensively in 2D and 3D. The element movement technique has been shown to be very effective in simulating the filler material deposition leading to a reduction in the analysis time. However, when attempted for wider fields of applications, it had some limitations, especially when moving the elements towards the base-plate. In this paper, the element interaction technique is introduced utilizing the concepts of both the element movement and element birth techniques. The new technique is verified versus the currently developed procedures. In this technique, the elements of the weld pool are held in place in contact with the elements of the base-plate and the interaction is made to be a function of time. This gave several flexibilities in modeling the welding process. Hence, the technique is then used to analyze simple fillet welding of a plate and circumferential butt-welding of a pipe. INTRODUCTION The residual stresses generated during welding vary with the change in the welding parameters depending on the procedure of the joining process. Many researches have been done to investigate the residual stress for specific problem. Due to the complexity of the different applications, several assumptions and approximations, such as reducing the model from 3D to 2D, are made to facilitate the analysis. These approximations help mainly in reducing modeling efforts and analysis time. The element birth technique has been used in simulating metal deposition in both 3D and 2D models. Brown and Song [1] have used the technique in an axisymmetric simulation of a fillet-weld of ringstiffened cylinder. Wilkening and Snow [2] have also solved an axisymmetric simulation of a two-pass butt-weld of a cylinder using the element birth technique. Also, for a plate, they assumed that the through thickness variation of the residual stress is insignificant, so they modeled a single-pass butt-weld of plate using 2D plane model of the plate. Bouchard et a

Integrated microfluidic tmRNA purification and real-time NASBA device for molecular diagnostics.

We demonstrate the first integrated microfluidic tmRNA purification and nucleic acid sequence-based amplification (NASBA) device incorporating real-time detection. The real-time amplification and detection step produces pathogen-specific response in < 3 min from the chip-purified RNA from 100 lysed bacteria. On-chip RNA purification uses a new silica bead immobilization method. On-chip amplification uses custom-designed high-selectivity primers and real-time detection uses molecular beacon fluorescent probe technology; both are integrated on-chip with NASBA. Present in all bacteria, tmRNA (10Sa RNA) includes organism-specific identification sequences, exhibits unusually high stability relative to mRNA, and has high copy number per organism; the latter two factors improve the limit of detection, accelerate time-to-positive response, and suit this approach ideally to the detection of small numbers of bacteria. Device efficacy was demonstrated by integrated on-chip purification, amplification, and real-time detection of 100 E. coli bacteria in 100 microL of crude lysate in under 30 min for the entire process

Prediction of Mechanical Properties for Curved Dumbbell- Shaped Specimen at Different Orientation Angles of Ring Hoop Tension Test

Manufacturing processes of polymeric plastic pipes play an important role and effect on their mechanical behavior. These processes cause a significant difference in the mechanical behavior between traditional tensile test specimens from the basic materials and final product of plastic pipes. The present study is focused on the mechanical behavior of ring specimens cut from pipes in the circumferential direction to obtain accurate materials design data during checking the quality of the final product for the plastic pipes. The experimental work is conducted at different crosshead speeds (VC.H = 10–1000 mm min−1) and different loading angles relative to the location of the dumbbell shaped (DBS) (α = 0°, 30°, 45°, 60°, and 90°) to study the mechanical properties of the ring hoop tension test (RHTT) specimens. The effect of loading angle of RHTT specimen is investigated at constant crosshead speed equal 50 mm min−1. The tensile test results show that the engineering hoop yield strength is maximized at loading angle, 90° for both single and double configurations compared with all loading angles at crosshead speed 50 mm min−1. The experimental results predict the yield point on the curved surface of DBS configuration based on the vertical displacement of the movable head for tensile testing machine

Maher Younan Oral History

Maher Younan was a faculty member in Engineering at the American University in Cairo from the 1990s through 2020s. He recalls his youth and education in Cairo, and university study and faculty position at Cairo University (undertaken after graduate school in the United States). He tells of joining AUC in 1993, and describes the Engineering Department, and its later division into Mechanical Engineering and other specialized departments under in the School of Sciences and Engineering (SSE). Younan outlines curriculum developments and new programs, recounts the effort to achieve accreditation for Engineering at AUC, and tells of his positions as Chair and SSE Associate Dean. He speaks about the Core Curriculum and the relationship between the liberal arts mission and professional education at AUC. Also covered are engineering facilities on the downtown and New Cairo campuses, including the move and the role of SSE Dean Medhat Haroun. He discusses students, including changes in their attitudes and academic approach over the years, the 2012 strike, and their careers after graduation. Faculty matters, such as the push for compensation equity for Egyptian nationals, are also addressed. Younan speaks about his research interests and university service contributions as well

Dynamics and combinatorics of 2 and 3 dimensional triangulations

We study in detail two aspects of 2 and 3 dimensional triangulations of the sphere. In the "Dynamics" part, we construct two models in statistical mechanics, on the set of all triangulations of $S^2$ and $S^3$ respectively, and we show that these models behave as glasses, in the sense that these models show a tremendous slowing down of their dynamics once we lower the temperature. We call such models "topological glasses". In the "combinatorics" part, we study the question of counting the number of triangulations of the 3d sphere $S^3$. This is an old and difficult question and even though we do not solve it, we make some very interesting contributions and we find results we strongly believe are a good step towards finding a solution