Feed Forward Back Propagation artificial neural network (ANN) model utilizing the MATLAB Neural Network Toolbox is designed for the prediction of surface roughness of Duplex Stainless Steel during orthogonal turning with uncoated carbide insert tool. Turning experiments were performed at various process conditions (feed rate, cutting speed, and cutting depth). Utilizing the Taguchi experimental design method, an optimum ANN architecture with the Levenberg-Marquardt training algorithm was obtained. Parametric research was performed with the optimized ANN architecture to report the impact of every turning parameter on the roughness of the surface. The results suggested that machining at a cutting speed of 355 rpm with a feed rate of 0.07 mm/rev and a depth of cut 0.4 mm was found to achieve lower surface roughness with, an increase in the cutting speed and feed rate with the increases of the surface roughness. In addition, an increase in the depth of cut was found to reduces the surface roughness. The outcome of this study showed that ANN is a versatile tool for prediction of surface roughness and may be easily extended with greater confidence to various metal cutting processes.
Background: the aim of this study was to evaluate the effect of different surface acids treatments (37%phospjoric acid, 5%hydrofluoric acid, 1.23 acidulated phosphate fluoride) of feldspathic ceramic VITA 3D MASTER , and the effect of thermocycling on shear bond strength using a ceramic repair kit (ivoclar/vivadent). Material and Methods: sixty Nickel-Chromium metal base plates were prepared(9mm diameter,3mm depth) using lost wax technique, 2mm thick layer of ceramic(VITA 3D MASTER) fused to metal plates, all specimens were embedded in acrylic resin blocks except their examined surfaces and divided into 3 main groups 20 specimens each, Grp A: treatment with 37%phosphoric acid for 2 mins, Grp B: etching with 5% hydrofluoric acid for 2mins,
... Show MoreAim of the study: This study's goal was to determine how laser surface alteration affected wettability of injectable thermoplastic acrylic and heat cure acrylic denture base materials. Materials and methods: Injectable thermoplastic acrylic resin (Deflex) and heat cure acrylic (Procryla) were used in this study to produce forty-disc shaped specimens, 20 specimens for each material type. The control group was made up of ten samples of each type of plastic denture base material. The other ten samples were treated with a nano-pulse fiber-optic lens Nd:YAG laser. The results were looked at with the Kruskal-Wallis test and the unpaired t-test (a=.05). Results: Compared to the control groups, the laser-treated groups were more likely to sti
... Show MoreThe objective of this study is to demonstrate the corrosion behavior of dental alloys Co-Cr-Mo, Ni-Cr-Mo and Ti-Al-V in artificial saliva at pH=4 and 37oC enriched with ethyl alcohol at 8% percentage. The linear and cyclic polarizations were investigated by electrochemical measurements. Laser surface modification was achieved for the three dental alloys to improve corrosion resistance. The results show that corrosion resistance of Co-Cr-Mo and Ni-Cr-Mo alloys only were increased after laser treatment due to the fact that laser radiation has caused a smoother surface, in addition to the decrement in corrosion current densities (icorr) for Co-Cr-Mo and Ni-Cr-Mo alloys and the reverse scan in cyclic polarization became in the wider range of
... Show MoreThe subject of this thesis acquired it's importance from many sides most
important of it , it's the nature of the relationship between Iraq-Syria relation
itself . which is basic on many close and fare relationship between them upon
the history , and also the changes that happened in global and regional area
after the 11th September 2001 and the changes of the American strategy upon
Syria , and the trying of the united states to qualify the Syrian role inside its
regional in the meddle east upon the changes that imposing by the united
states which is the most important event was the occupation of Iraq .
The importance of this subject is also due to the occupation of the united
states upon the Iraq on April 2003
Presupposition, which indicates a prior assumption, is a vital notion in both semantic and pragmatic disciplines. It refers to assumptions implicitly made by interlocutors, which are necessary for the correct interpretation of an utterance. Although there is a general agreement that presupposition is a universal property of Language, there are various propositions concerning its nature. However, this research work proposes that presupposition is a contextual term, thus, is more pragmatic than semantic in its nature.Although Semantics and Pragmatics are two distinct disciplines, they are interrelated and complementary to each other, since meaning proper involves both, and since there is no clear borderline between the two disciplines. How
... Show Moreدراسة التسلح النووي مفهوم واهميه وأبعاد ودراسة القدرات النووية لكوريا الشمالية وتأثيراته الدولية والإقليمية
إن التعبير ينوء بأثقال كبيرة ، وهذه المشكلة قد تتضاعف ،لأنَّ التعبير يحتاج إلى مها ا رت " لم
تنجح المدرسة في تنميتها تنمية صحيحة " ولأنّهُ يصطدم بعوامل معوقة متعددة منها ثنائية اللغة ،
وكثافة الصفوف ، وغياب المنهج ، وٕاهمال التصحيح، ووضع المدرس لكلمة "لوحظ" من غير
ملاحظة شيء وقلة الحصص ، وضعف الربط بين فروع اللغة ، والتساهل في إعداد المدرس.
وقد كان من نتائج د ا رسة أجرتها المنظمة العربية للتربية والثقافة
السياسة التركية تجاه عراق ما بعد الانتخابات