The progression of chronic renal failure: An unmet challenge

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An improved quadratic program for unweighted Euclidean 1-center location problem

AbstractIn this paper, an improved quadratic programing formulation for the solution of unweighted Euclidean 1-center location problem is presented. The original quadratic program is proposed by Nair and Chandrasekaran in 1971. Besides, they proposed a geometric approach for problem solving. Then, they concluded that the geometric approach is more efficient than the quadratic program. This conclusion is true only when all decision variables are treated as nonnegative variables. To improve the quadratic program, one of those variables should be an unrestricted variable as it is presented here. Numerically we proved that the improved quadratic program leads to the optimal solution of the problem in parts of second regardless of the size of the problem. Moreover, constrained version of the problem is solved optimally via the improved quadratic program in parts of second

Analisis Perilaku Konfigurasi Pelat Pengaku pada Sistem Struktur Steel Plate Shear Wall (SPSW) yang Tersambung pada Sisi Horizontal Boundary Element (HBE)

Sistem Steel Plate Shear Wall (SPSW) adalah sebuah sistem struktur yang mampu menunjukkan deformasi kekakuan awal yang tinggi, berperilaku daktail, dan mendisipasi energi yang besar, sehingga cocok menjadi sistem penahan gempa yang besar. Pelepasan pelat pengisi pada kolom dapat menguntungkan karena kemungkinan kegagalan awal yang terjadi pada kolom dapat diminimalisir. Untuk meningkatkan gaya geser dan disipasi energi maka perlu adanya penambahan pelat pengaku pada elemen shearwall. Pada penelitian ini dilakukan pengujian terhadap beberapa model konfigurasi pelat pengaku yaitu diantaranya; berbentuk cross dan strip model. Hasil pengujian yaitu berupa; diagram kurva histeresis, pola deformasi pelat, kapasitas disipasi energi dan kapasitas gaya geser. Penelitian ini menggunakan metode elemen hingga dengan program bantu ABAQUS. Hasil penelitian menunjukkan bahwa penambahan pelat pengaku pada daerah TFA (tension field action) memiliki pengaruh yang sangat signifikan dalam meningkatkan kekakuan awal yang baik, meningkatkan kapasitas gaya geser dan menghasilkan disipasi energi yang sangat baik

Comparison and Evaluation of Deadlock Prevention Methods for Different Size Automated Manufacturing Systems

In automated manufacturing systems (AMSs), deadlocks problems can arise due to limited shared resources. Petri nets are an effective tool to prevent deadlocks in AMSs. In this paper, a simulation based on existing deadlock prevention policies and different Petri net models are considered to explore whether a permissive liveness-enforcing Petri net supervisor can provide better time performance. The work of simulation is implemented as follows. (1) Assign the time to the controlled Petri net models, which leads to timed Petri nets. (2) Build the Petri net model using MATLAB software. (3) Run and simulate the model, and simulation results are analyzed to determine which existing policies are suitable for different systems. Siphons and iterative methods are used for deadlocks prevention. Finally, the computational results show that the selected deadlock policies may not imply high resource utilization and plant productivity, which have been shown theoretically in previous publications. However, for all selected AMSs, the iterative methods always lead to structurally and computationally complex liveness-enforcing net supervisors compared to the siphons methods. Moreover, they can provide better behavioral permissiveness than siphons methods for small systems. For large systems, a strict minimal siphon method leads to better behavioral permissiveness than the other methods

A Comparison Study in the Management of Ectopic Pregnancy between State of Qatar and Kingdom of Bahrain

Ectopic pregnancy is of increasing concern to gynecologists since it is a major cause of maternal mortality and morbidity in reproductive age women. It occurs when the conceptus implants in an abnormal position other than the uterus. Although the incidence of ectopic pregnancy during the 20 years studied increased five-folds, the risk of death from ectopic pregnancy declined by 90%. This decline might be related to the increase awareness of this condition that accompanied improved diagnostic technology and thus improved management and care. However, ectopic pregnancy remains the leading cause of maternal mortality in first trimenster. This study was to evaluate the management of ectopic pregnancy in the State of Qatar and the Kingdom of Bahrain in a time period from January I, 2000 to August 31, 2003. Statistical analysis showed high incidence of ectopic pregnancy with increase in age and abortion. Etiological factors including contraceptive usage, infertility treatment and previous ectopic pregnancy were shown to increases ectopic pregnancy rates. In the Kingdom of Bahrain, management of ectopic pregnancy was carried by surgical salpingectomy and Laparoctomy and to a lesser extend medical Methotrexate management was also carried on. While in the State of Qatar it was the opposite as Methotrexate was mainly used rather than the surgical treatment. It is recommended that further investigations are needed to enhance this data and to prove the benefits of medical management over the surgical management.qscienc

Confusion Control in Generalized Petri Nets Using Synchronized Events

The loss of conflicting information in a Petri net (PN), usually called confusions, leads to incomplete and faulty system behavior. Confusions, as an unfortunate phenomenon in discrete event systems modeled with Petri nets, are caused by the frequent interlacement of conflicting and concurrent transitions. In this paper, confusions are defined and investigated in bounded generalized PNs. A reasonable control strategy for conflicts and confusions in a PN is formulated by proposing elementary conflict resolution sequences (ECRSs) and a class of local synchronized Petri nets (LSPNs). Two control algorithms are reported to control the appeared confusions by generating a series of external events. Finally, an example of confusion analysis and control in an automated manufacturing system is presented

3-(Adamantan-1-yl)-1-[(4-ethyl­piperazin-1-yl)meth­yl]-4-[(E)-(4-hy­droxy­benzyl­idene)amino]-1H-1,2,4-triazole-5(4H)-thione

In the title thione, C26H36N6OS, the 1,2,4-triazole ring is planar (r.m.s. deviation = 0.020 Å) and the benzene ring is twisted out of this plane [dihedral angle = 62.35 (12)°]. Supra­molecular zigzag chains feature in the crystal packing. These are sustained by O—H⋯N(piperazine) hydrogen bonds, and are connected into the three-dimensional crystal structure by C—H⋯S and C—H⋯O inter­actions. The crystal studied was a racemic twin

3-(Adamantan-1-yl)-4-methyl-1-[(4-phenyl­piperazin-1-yl)meth­yl]-1H-1,2,4-triazole-5(4H)-thione dichloro­methane hemisolvate

The asymmetric unit of the title dichloro­methane hemisolvate, C24H33N5S·0.5CH2Cl2, comprises an adamantan­yl/triazole derivative and half a CH2Cl2 mol­ecule of crystallization; the latter is disordered about a twofold axis of symmetry. The piperazine ring has a chair conformation and the two N-bound substituents occupy equatorial positions. The piperazine residue is almost normal to the triazole ring [N—N—C—N torsion angle = −79.9 (3)°] so that to a first approximation, the mol­ecule has an L-shape. Linear supra­molecular chains parallel to [001] are formed via C—H⋯S inter­actions. Two such chains are linked into a double chain via C—H⋯Cl inter­actions involving the disordered CH2Cl2 mol­ecules of solvation

3-(Adamantan-1-yl)-1-[(4-benzyl­piperazin-1-yl)meth­yl]-4-[(E)-(2-hy­droxy­benzyl­idene)amino]-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C31H38N6OS, the conformation about the N=C [1.285 (2) Å] imine bond is E. The piperazine ring has a chair conformation and occupies a position almost perpendicular to the plane through the triazole ring; the benzene ring forms a dihedral angle of 31.95 (10)° with the triazole ring. Overall, the mol­ecule has the shape of a flattened bowl. The hy­droxy group is disordered over two positions. The major component has a site-occupancy factor of 0.762 (3) and forms an intra­molecular O—H⋯N(imine) bond to close an S(6) loop. The minor component of the disordered hy­droxy group forms an O—H⋯N(piperazine) hydrogen bond. These, along with C—H⋯S and C—H⋯N inter­actions, link mol­ecules into a three-dimensional architecture