نتایج جستجو برای: Fracture systems

تعداد نتایج: 1274852  

Journal: :جنگل و فرآورده های چوب 0
حمیده عبدل زاده فارغ التحصیل دکتری علوم و صنایع چوب و کاغذ دانشکدة منابع طبیعی دانشگاه تهران، ایران محمد لایقی استادیار گروه علوم و صنایع چوب و کاغذ دانشکدة منابع طبیعی دانشگاه تهران، ایران قنبر ابراهیمی استاد گروه علوم و صنایع چوب و کاغذ دانشکدة منابع طبیعی دانشگاه تهران، ایران

fracture of mixed mode i/ii in beech wood and its wood polymers has been investigated experimentally in this study. hence, two crack systems of tl and rl were selected in which the crack planes extend along the wood fibers. this investigation has demonstrated that onset of mixed mode cracking can be predicted with a very simple fracture criterion in these crack systems. results indicated that f...

A. Formisano G. De Matteis H. Monsef Ahmad, M. R. Sheidaii S. Tariverdilo

Thin perforated Steel Plate Shear (SPS) Walls are among the most common types of energy dissipating systems. The applied holes reduce the shear strength of the plate and allow to decrease the profile size of the members at the boundary of the panel when these systems are used in the typical design of structures. On the other hand, the different fracture locations of these panels are visible whe...

Journal: :iranian endodontic journal 0
fariborz vafaee department of prosthodontics, dental school/dental research center, hamadan university of medical sciences, hamadan, iran masoumeh khoshhal department of periodontics, dental school, hamadan university of medical sciences, hamadan, iran. aliakbar rezaei department of prosthodontics, dental school, shahid beheshti university of medical sciences, tehran, iran. fereidon sooltani department of prosthodontics, dental school, shahid beheshti university of medical sciences, tehran, iran. mohsen jalal zadeh department of endodontics, dental school, hamadan university of medical sciences, hamadan, iran. ali yalpaniyan mechanical engineer msc, tehran, iran.

introduction: the resistance to fracture of endodontically treated teeth restored with esthetic post systems has not been extensively researched. this in vitro study compared the fracture patterns of endodontically treated teeth with esthetic post systems with different analysis methods. materials and methods: a total of 26 recently extracted human maxillary central incisors were decoronated an...

Journal: :journal of dentistry, shiraz university of medical sciences 0
amir ali reza khaledi dept. of prosthodontic, school of dentistry, shiraz university of medical sciences, shiraz, iran. shekufe sheykhian students’ research committee, school of dentistry, international branch, shiraz university of medical sciences, shiraz, iran. arash khodaei students’ research committee, school of dentistry, international branch, shiraz university of medical sciences, shiraz, iran.

statement of the problem: the survival of pulpless teeth restored with different post and core systems is still a controversial issue. purpose: this study compared the retention of two different post and core systems and also the fracture resistance of teeth restored with these systems. material and method: eighty endodontically treated maxillary central incisors were sectioned perpendicular to...

Fault zones and fault-related fracture systems control the mechanical behaviors and fluid-flow properties of the Earth’s crust. Furthermore, nowadays, modeling is being increasingly used in order to understand the behavior of rock masses, and to determine their characteristics. In this work, fault zones and fracture patterns are reviewed, and also comprehensive studies are carried out on the fr...

Cyrus Ghotbi, Reza Azin, Riyaz Kharrat, Shapour Vossoughi

The vapor extraction (VAPEX) process, a solvent-based enhanced oil recovery process has been found promising for some heavy oil reservoirs. In this work, the VAPEX process is studied using a compositional simulator on a number of single-block and multiple block fractured systems. PVT data of one of an Iranian heavy oil reservoir are used to tune the equation of state. Effects of fracture sp...

Journal: :galen medical journal 0
anahita safari school of dentistry, shiraz university of medical science, shiraz, iran amir alireza khaledi school of dentistry, shiraz university of medical science, shiraz, iran zeinab shafiee school of dentistry, shiraz university of medical science, shiraz, iran naeeme rahmani school of dentistry, shiraz university of medical science, shiraz, iran

background : in anterior endodontically treated teeth a better esthetic can be achieved by using all-ceramic post -core restorations instead of metal post systems. maximum retention and fracture resistance of the post are the criteria upon which selection of a post system is based. the aim of this study was to evaluate the fracture resistance and retention of two all-ceramic post and core syste...

Journal: :iranian endodontic journal 0
yaser safi mohammad mehdi aghdasi fatemeh ezoddini-ardakani samira beiraghi zahra vasegh

introduction: vertical root fracture (vrf) is common in endodontically treated teeth. conventional and digital radiographies have limitations for detection of vrfs. cone-beam computed tomography (cbct) offers greater detection accuracy of vrfs in comparison with conventional radiography. this study compared the effects of metal artifacts on detection of vrfs by using two cbct systems. methods a...

Journal: :dental research journal 0
vajihesadat mortazavi mohammadhossein fathi najmeh katiraei shirin shahnaseri hamid badrian navid khalighinejad

background: with the aim of developing methods that could increase the fracture resistance of structurally compromised endodontically treated teeth, this study was conducted to compare the effect of three esthetic post systems on the fracture resistance and failure modes of structurally compromised and normal roots. materials and methods: forty five extracted and endodontically treated maxillar...

Journal: :journal of dentistry, tehran university of medical sciences 0
m. sadeghi

statement of problem: it is yet unclear whether fiber-reinforced composite posts can enhance the mechanical properties and prevent vertical fractures of teeth under chewing loads. purpose: the purpose of this study was to compare the fracture resistance and failure mode of endodontically treated teeth restored with three different post systems. materials and methods: thirty-six maxillary canine...

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