Sharif Digital Repository

Lumped method (Electrical analogy) is a quick and easy way to model human cardiovascular system. In this paper Lumped method is used for simulating a complete model. It describes a 36-vessel model and cardiac system of human body with details that could show hydrodynamic parameters of cardiovascular system. Also this paper includes modeling of pulmonary, atrium, left and right ventricles with their equivalent circuits. Exact modeling of right and left ventricles pressure with division of ascending aorta into 27 segments increases the accuracy of our simulation. In this paper we show that a calculated pressure for aorta from our complex circuit is near to measured pressure by using advanced... 

This paper studies the effective parameters of a skilled service in playing tennis and determines their relationship with skill deals. Effective service in tennis plays an important role in gaining more desirable result and the most important factor of success in getting scores depends on the player's skills in serving an effective service. The characteristics of a good service are the high speed of the ball and the precision of landing the ball. The several parameters affecting on these two characteristic in the service, are studied in this paper. Therefore, the Kinematic parameters of 8 Iranian professional tennis athletes of first division tennis league and also 8 non-professional Iranian... 

A comparative investigation has been developed for the stability constants of several amino acid complexes with divalent metal ions, which have been determined by potentiometric pH titration. Depending on the metal ion-binding properties, vital differences in the building complexes were observed. The present study indicates that in some M(L) complexes, metal ions are arranged in carboxyl groups, but in other M(L)complexes, some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(L) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of... 

The acidity and stability constants of M-Met (M: M2+; Met 1: L-methionine) complexes, determined by potentiometric pH titrations, were used to make a comparative investigation with L-cysteine (Cys). It is shown that regarding to M ion - binding properties vital differences on complex bilding were considered. It is demonstrated, that in M-Met complexes, M ion is coordinated to the carboxyl group, M ion is also able to build macrochelate over amine group. The upmentioned results demonstrate that for M-Met complex the stability constants is also largly determined by the affinity of Cu2+ for amino group but in opposite to Met, some metal ions such as Co2+, Cu2+, and Zn2+ build with Cys 2... 

Waste water from ore plant layout central Alborz's coal has been investigated and analyzed. Studies showed that because of acidic character, the waste water contains heavy metals including Cu, Cr, Ba, Zn, V, Sr, Pb, Ni. Considering the importance of this topic for outgoing acidic waste waters which is hazardous for the environment, i.e. heavy metals, the same should not be transferred into the environment. Since their waste water is transferred into nearby agricultural ground, it was developed a method, so that waste water is primarily directed into a slug pond for sedimentation. In the second stage in another pond, the outflow of waste water was treated with chemicals. Also the pH was... 

In the past two decades, microfluidic systems have become more appealing due to their wide applications in many areas, such as electronics, biotechnology, medicine, etc. Recently, the advantages of using the bubble growth phenomenon as a robust actuator in microfluidic devices have directed research interests towards the investigation of various applications. In this research, a new transient thermo-hydraulic model has been developed for bubble growth in confined volumes. The present model has been used to describe the pumping effect produced by the bubble growth and collapse phenomenon in microchannels. The results show relatively good agreement with experimental data. This study is useful... 

The thermal behavior of Fe3Si2O5(OH)4·Sb3O6(OH)·Sb2O3 (a sample of antimony from Sefidabe mine in Zahedan) was investigated by the technique of thermogravimetry under air atmosphere from 25 to 1200 °C. The obtained results from TGA were reported. This study reports comprehensive information about these minerals. XRD and XRF techniques, UV/visible and elemental analysis such as ICP are used to identify the products at different decomposition steps. The acidic leaching of this mineral Fe3Si2O5(OH)4·Sb3O6(OH)·Sb2O3 is carried out, and the obtained results are reported. In total, the recovery was achieved by leaching with hydrochloric acid was 85% at D80 granulation below 45 microns. In leaching... 

Using two techniques of thermogravimetry and differential scanning calorimetry under O2 and N2 gas atmosphere from 25 to 600 °C, the thermal behavior of chromium(VI) oxide CrO3 was investigated. The identity of products at different decomposition steps was confirmed by XRD technique. Both techniques produced similar results supporting the same steps for the compound. The received products were investigated by SEM electron microscope. The form and the size of crystals were investigated. Three distinct energy changes were observed, namely, two endothermic and one exothermic in DSC. The amount of ΔH for each peak is also reported  

During the recent decade, high induction diffusers have become more appealing in applications which require relatively high ventilation airflow rates, such as clean rooms. In this research, the effect of geometric parameters on the performance of a specific type of swirling air diffuser is investigated numerically. The results show that although the diffuser slots geometry, namely their angle and aspect ratio, is impressive on the diffuser performance, it is not as important as the swirling blade angle and the performance is almost constant in a wide range of slots specifications. The results also demonstrate that the diffuser performance and the resultant indoor airflow distribution highly... 

Surgical site infection (SSI) is one of the important infectious problems in hospitals. It is well known that appropriate ventilation strategy is most effective way to control bacteria-carrying airborne particles responsible for SSI. With considerable improvement in the computational capacity of computers, computational fluid dynamics (CFD) technique has been widely used to study the indoor airflow and contaminant dispersion over the enclosures. In this research, the effect of inlet air velocity on the ultra-clean ventilation system performance is investigated Eulerian-Lagrangian numerical approach. The results show that surgical wound contamination may be highly affected by inlet velocity.... 

Increasing concerns about global warming and environmental pollution control has pushed the relevant organizations to set regulations and to develop programs for energy saving. In addition, for many high energy using appliances, energy labeling provides the end user with important data to select energy-efficient equipments and encourage the manufacturers to enhance the performance of their productions. In this research, a new energy-saving program for wet cooling towers has been developed. Considering a thermo-hydraulic analysis, a novel Energy Index (IE) has been extracted which takes all aspects of the problem into account. The present index can be used as a proper criterion for energy... 

Social norms are a core concept in social sciences and play a critical role in regulating a society's behavior. Organizations and even governmental bodies use this social component to tackle varying challenges in the society, as it is a less costly alternative to establishing new laws and regulations. Social networks are an important and effective infrastructure in which social norms can evolve. Therefore, there is a need for theoretical models for studying the spread of social norms in social networks. In this paper, by using the intrinsic properties of norms, we redefine and tune the Rescorla-Wagner conditioning model in order to obtain an effective model for the spread of social norms. We... 

The primary source of surgical site infection is the deposition of flakes released from the exposed skin of surgical staff or the patient on the exposed surgical wound. In this study, a computational model for simulating air ow and thermal conditions in an operating room is developed, and transport and deposition of particulate contaminants near the wound are analyzed. The results show the formation of a thermal plume over the wound tissue, which is typically at a higher temperature than the surrounding. The thermal plume protects the wound from the deposition of contaminants. In addition, the computational model predicts an optimum value for the inlet air velocity that is mainly maintaining... 

PbCO 3·PbO and PbCO 3·2PbO compounds were prepared by thermal methods. The structure of each compound was determined by using XRD technique, and their purity was confirmed by analytical methods (98%). Also the thermal characteristics of each compound were investigated by thermogravimetry. At 600°C both compounds decompose completely and produce lead(II) oxide. © 2006 Nauka/Interperiodica  

Nowadays, as the oil reservoirs reaching their half-life, using enhanced oil recovery methods is more necessary and more common. Simulations are the synthetic process of real systems. In this study, simulation of water and surfactant injection into a porous media containing oil (two-phase) was performed using the computational fluid dynamics method on the image of a real micro-model. Also, the selected anionic surfactant is sodium dodecyl sulfate, which is more effective in sand reservoirs. The effect of using surfactant depends on its concentration. This dependence on concentration in using injection compounds is referred to as critical micelle concentration (CMC). In this study, an...