Serous otitis or otitis media with effusion is one of the common diseases which if left untreated can lead to complications like tympanic membrane atrophy, cholesteatoma formation, behavioural changes, osteonecrosis and sensori - nueral deafness. One of the treatment options for serous otitis is VT placement which has its own complications like ottorhea, perforation and tympano - sclerosis. The rejection time of VT is closely related to the location of the VENTILATION tube. The complications arising due to VT placement are related to the time period since placement of the tube, social status of the patient, age, personal hygiene including prevention of water entry into the affected ear, etc. This prospective analytical survey with a one year follow up was carried out on children suffering from serous otitis who had been operated (VT placement) during the first half of 1378 at Shahid Rahnemom Hospital. Most of the VT rejections in all age groups occurred about 7-9 months after the operation but no significant difference was observed between the age groups. In the study determining the relation between gender and VT rejection time (P.V= 0.536), it was realized that the maximum number of VT rejections were between 3-6 months after the operation (47.7%) of which 44.3% was seen in boys and 51.9% in girls, thus, no significant difference was observed between the two sexes (P.V=0.691). 33.9% of the total had ottorhea. 35.1 % sclerosis, and 3.4% had a perforation. 27.6% of the patients had no complications. 7.7% of those patients who had a VT in the anterosuperior compartment of the tympanic membrane had a perforation, while only 2.7% of those who had a VT in the postero – interior compartment had a perforation. Age and gender have no effect on VT rejection time. The probability of a VT remaining in place is more in Shepherd type VENTILATION tubes than Richard type VT. VENTILATION tubes placed in the antero - inferior quadrant are rejected earlier than those placed in the antero - superior quadrant. In the population under study, perforation is the least occurring complication in all age groups. There is on significant difference in the complications arising in either gender.      

BACKGROUND: Thoracoscopy is a minimally invasive method used in diagnosis and treatment of many disorders in animals, however, its application in smaller species is limited in literature which can be contributed to the challenges faced while performing a minimally invasive procedure in smaller mammals. OBJECTIVES: Evaluating the feasibility and ideal port placement considering heart as the target organ in rabbit. Also, the impact of VENTILATION protocol on rate of mortality was evaluated. METHODS: Twenty New Zealand white rabbits were used in this experiment. Approaches used for the introduction of the camera were Para-xiphoid and intercostal space, the optimal spot for insertion of the second trocar relative to the camera was also evaluated, lung damage and rate of mortality were assessed under two different mechanical VENTILATION modes of pressure-controlled and volume-controlled. RESULTS: Surgical view gained through the para-xiphoid approach is rather panoramic and spatial than the direct intercostal view, maneuver on the heart with an instrument is easier when the 5th intercostal space is used for the second trocar. With the help of PCV, lungs sustain less damage and atelectasis can be avoided till the end of the procedure and therefore, less mortality is experienced. CONCLUSIONS: Using the Para-xiphoid approach and the correct VENTILATION protocol provides sufficient working space under good vison, which makes the rabbit thoracoscopic heart model a practical model that can be used in many cardiac experiments.

Background: Airborn lead level in Tehran's radiator repair plants is six times higher than the standard level. This high percentage necessitates evaluating engineering controls and efficient VENTILATION system in these plants. Objective: To evaluate cost-effective VENTILATION ENCLOSURE made of a flexible silicone sheet that forms a tent-like structure verthe water bath that is used to leak test radiators. Methods: Through an experimental study, the samples were gathered from 10 radiators repair plants which had no technical control the effectiveness of this VENTILATION ENCLOSURE was evaluated by collecting short-term and time-weighted average personal samples for lead data (controlled work-station) that used the ENCLOSURE. In addition, similar Personal breathing zone samples for lead were collected at a work-station in the same facility without the ENCLOSURE (uncontrolled). Finding: Lead exposure during radiator repair at the controlled work-station was 24 µg/m3  (50% of OSHA PEL). Personal breathing zone samples taken at uncontrolled work-stations averaged 143 µg/m3 which was 7 times higher than controlled stations. Conclusion: The results demonstrated an excellent control of lead fumes using this VENTILATION ENCLOSURE.      

There are two main methods in fire modeling: zone models and field models. The conservation of mass and energy in ENCLOSURE is the theoretical base of zone models. The models deal with heat release rate, fire plume, mass flow, smoke movement and gas temperature in fires. Theoretical principles of compartment fire zone modeling are presented and the behavior of fire in ENCLOSUREs is discussed. The conservation laws are presented in control volume form and applied to the behavior of fire in ENCLOSUREs. The governing equations are derived and presented. Some zone models and their field of application in fire modeling are also given.

Introduction: Nowadays, cities are facing problems such as overheating caused by urban congestion, causing thermal islands and environmental problems, which make life difficult in some places. The wind flow in the urban environment is an important factor affecting the exchange of heat and moisture, particle transport, and urban VENTILATION. Studies show that physical factors such as ENCLOSURE change, the elevation of buildings, and different orientations of passageways in urban texture affect the speed and direction of the wind flow. The purpose of this study was to analyze climate data related to wind flow in two urban areas of Dezful and investigate the effect of ENCLOSURE of passages on the wind flow. Material and methods: In order to carry out the study, two areas of Siah-Pushan and Gozare-Shahi in the range of histori� cal texture of Dezful, with similar and different physical factors, were selected for the analysis of physical conditions by comparing climate data. Data on the intensity of the wind and the ambient temperature of both areas in five periods of 9-11 am, 11am-1 pm, 2-4 pm, 4-6 pm, and 6-8 pm, and in two seasons, winter and summer, were selected. Then, the ENCLOSURE of the collected points was calculated and using the linear regression analysis, the relationship between ENCLOSURE and wind speed was assessed. Results and discussion: The results showed that the velocity of the southwest-northeast wind flow was more than other ori� entations. Also, surveys showed that increasing the specific ENCLOSURE can increase the wind speed by a certain magnitude. In Gozare-Shahi, the results of the regression diagrams in the winter indicated that a direct relationship exists between the ENCLOSURE of the cross-sections and the velocity of the wind. With the minimum ENCLOSURE (0. 35) increasing 1. 5 to 3 times, the initial velocity of wind increased up to 31-121 percent. The results of the linear regression diagrams in Siah-Pushan in� dicated that with 2 to 6 times increase in the ENCLOSURE, the wind speed increases up to 1. 1 to 1. 8 times. The results obtained from the linear regression diagrams in Gozare-Shahi passage showed that the ENCLOSURE of passways and the velocity of the wind flow are directly correlated. With the minimum ENCLOSURE (0. 35) increasing 1. 5 to 3 fold, the initial velocity of the wind increased 10 to 40 percent. In Siah-Pushan range, the ENCLOSURE of transitions was directly correlated with the wind. Also, the results showed that by increasing the ENCLOSURE up to 2 to 6 times, the velocity of the wind increased 1. 03 to 1. 20 times. Conclusion: Increasing the velocity of the wind led to better VENTILATION in the urban environment. On the other hand, in� creasing the ENCLOSURE increased the velocity. Uniform buildings, as well as regular ENCLOSUREs with the least changes, will increase the velocity of the wind stream, as well as less turbulence. Thus, increasing ENCLOSURE, as well as regular buildings, can ultimately lead to better urban environments.

The problem of steady, laminar and incompressible natural convection flow in an octagonalENCLOSURE was studied. In this investigation, two horizontal walls were maintained at a constant hightemperature, two vertical walls were kept at a constant low temperature and all inclined walls wereconsidered adiabatic. The ENCLOSURE was assumed to be filled with a Bousinessq fluid. The studyincludes computations for different Prandtl numbers Pr such as 0.71, 7, 20 and 50 whereas the Rayleighnumber Ra was varied from 103 to 106. The pressure-velocity form of Navier-Stokes equations andenergy equation was used to represent the mass, momentum and energy conservations of the fluidmedium in the ENCLOSURE. The governing equations and boundary conditions were converted todimentionless form and solved numerically by penalty finite element method with discretization bytriangular mesh elements. Flow and heat transfer characteristics were presented in terms of streamlines, isotherms and average Nusselt number Nu. Results showed that the effect of Ra on the convection heattransfer phenomenon inside the ENCLOSURE was significant for all values of Pr studied (0.71-50). It wasalso found that, Pr influence natural convection inside the ENCLOSURE at high Ra (Ra > 104).

In this paper, shielding effectiveness (SE) of a perforated ENCLOSURE with imperfectly conducting walls is evaluated. To this end, first, an accurate numerical technique based on method of Moments (MoM) is presented. In this method, lossy metallic walls of the ENCLOSURE are replaced by equivalent electric surface current sources. Then, the impedance boundary condition on the imperfectly conducting surfaces is applied and an electric field integral equation is extracted. At the end, the integral equation is solved numerically by Galerkin method. In addition to the mentioned numerical method, an extremely fast analytical technique based on transmission line model (TLM) is proposed which is able to predict the SE with high level of accuracy over a large frequency bandwidth just in a few seconds. For validation of both methods, other commercial softwares (FEKO and CST) are employed and several ENCLOSUREs with different conductivities are studied. Lossy MoM method shows accurate results for conductivities down to 10S/m, while efficient TLM method proves its accuracy for conductivities down to 250S/m.