پلاستیک ها، الاستومر ها و کامپوزیت ها به منظور کنترل خوردگی

 Using Plastics, Elastomers, and Composites for Corrosion Control

استفاده از پلاستیک ها، الاستومر ها و کامپوزیت ها به منظور کنترل خوردگی 

ABSTRACT

This chapter provides a broad overview of the application of polymers used for corrosion control in the chemical proces- sing industry. The generalizations offered about polymer performance might suggest possible approaches, but they should not be considered as recommendations owing to the complexity of equipment design and the many variables of chemical processing. Consultations with experts, analyses of case histories, and testing are essential to the success of these materials.

 

افزودن تیتانیم روی فولاد کم آلیاژ استحکام بالا Effect of Titanium Addition on HSLA Steel

Study on the Mechanism of Strengthening and Toughening Effect

 of Titanium Addition on HSLA Steel 

مطالعه‌ی مکانیزم استحکام‌بخشی و اثر چقرمه‌سازی افزودن تیتانیم روی فولاد HSLA

ABSTRACT

Based on the determination of load variation against deflection by means of Instrumented Charpy Impact testing, the impact energy distribution of the High Strength Low Alloy (HSLA) steel containing Nb, Ni and Ti for pressure vessels at low temperature has been quantitatively studied. The total impact energy Et could be divided into two parts, Ei  and Ep. Ei is related to the base strength of the material in terms of the grain size and alloy addition, which is also found to be less influenced by the holding time of normalization process at 910℃. Whereas, Ep of Ni-Nb-Ti HSLA steel is strongly linked to the period of holding time. Thermodynamic kinetic investigation was  carried out to study the strengthening mechanism with metallurgical microstructure analysis. 

 

مواد کنتاکت از جنس آلیاژ قلع-نقره AgSnO2 Electrical Contact Materials

Research on the Organization Performance of

AgSnO2 Electrical Contact Materials

پژوهشی درباره‌ی رفتار تشکیل در مواد کنتاکت از جنس AgSnO2 

ABSTRACT

In electrical contact materials, silver metal oxide (AgMeO) materials because has good resistance to  abrasion, fusion welding resistance and electrical conductivity, is widely used in low-voltage  electrical appliances. And  silver cadmium oxide (AgCdO) because it has excellent electric arc  erosion resistance, fusion welding resistance so was widely used in from a few volts to kv in a  variety of low-voltage electrical appliances. The material because of a series of excellent  performance has been called the universal contact.

 

بهبود یک فولاد میکروآلیاژی HSLA با وانادیم و تیتانیم

Effect of vanadium and titanium modification on the microstructure and

mechanical properties of a microalloyed HSLA steel

اثر بهبود یک‌نوع فولاد میکروآلیاژی HSLA با وانادیم و تیتانیم بر ریزساختار و خواص مکانیکی آن

ABSTRACT

Microalloyed high-strength low-alloy (HSLA) steels are essentially low carbon low-alloy steels that contain small additions (0.001–0.1wt.%) of alloying elements such as Nb, V, or Ti. These steels exhibit an outstanding combination of high strength, resistance to brittle fracture and good weldability, particularly if the carbon content is kept below ∼0.1wt.% . Several categories of HSLA steels have been developed catering to the needs of specific applications, such as the construction of large ships, oil and gas transmission lines, and offshore oil drilling platforms.

 

آنالیز میکروسکوپ تونلی روبشی STM و میکروسکوپ نیروی روبشی SFM

scanning tunneling microscope (STM) 

Scanning Force Microscopy (SFM)

آنالیز میکروسکوپ تونلی روبشی STM و میکروسکوپ نیروی روبشی  SFM

ABSTRACT

Scanning tunneling microscopy (STM) and its offspring, scanning force microscopy (SFM) , are real-space imaging techniques that can produce topographic images of a surface with atomic resolution in all three dimensions. Almost any solid surface can be studied with STM or SFM : insulators, semiconductors, and conductors, transparent as well as opaque materials. Surfaces can be studied in air, in liquid, or in ultrahigh vacuum, with fields of view from atoms to greater than 250*250um. With this flexibility in both the operating environment and types of samples that can be studied, STM/SFM is a powerful imaging system.

 

سلول های خورشیدی از تک کریستال های Si تا مواد متخلخل

A review on solar cells from Si-single crystals

to porous materials and quantum dots

مروری بر سلول های خورشیدی از تک کریستال های Si تا نقاط کوانتومی و مواد متخلخل

ABSTRACT

Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12–16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper–indium–selenide) and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. 

 

زینترینگ سرامیک های Nd:YAG شفاف تحت اتمسفر اکسیژن

Sintering of transparent Nd:YAG ceramics in oxygen atmosphere 

زینترینگ سرامیک های Nd:YAG شفاف تحت اتمسفر اکسیژن

ABSTRACT

Yttrium aluminum garnet (YAG) transparent ceramics were fabricated by sintering at oxygen atmosphere. Tetraethyl orthosilicate (TEOS) was added as the sintering additive to control the grain growth and densification. Pores were eliminated clearly at temperature lower than 1700 °C, while grain size was around 3 μm. The in-line transmittance was 80% at 1064 nm when samples were sintered at 1710 °C. The effect of TEOS was studied in oxygen atmosphere sintering for Nd:YAG transparent ceramics. At higher temperature like 1710 °C, the grain growth mechanism was solute drag, while at 1630 and 1550 °C the grain growth was controlled by liquid phase sintering mechanism. And 0.5 wt.% TEOS was the best adding content for Nd:YAG sintered in oxygen atmosphere.

 

تک کریستال Si تشکیل شده روی لایه آمورف در دمای پایین

Single-crystal Si formed on amorphous substrate at

low temperature by nanopatterning and

nickel-induced lateral crystallization

تک کریستال Si تشکیل شده روی لایه آمورف در دمای پایین

ABSTRACT

Silicon-based thin film transistors ~TFTs! on an amor- phous substrate have many important applications, including active matrix liquid-crystal display ~AMLCD! and future 3-dimensional ~3D! integrated circuits. However, silicon films deposited on amorphous substrate are typically in amorphous, microcrystalline, or polycrystalline states, which contain tremendous intrinsic defects, resulting in poor device performance and device-to-device nonuniformity. A single- crystal silicon film on amorphous substrate is highly desired but is difficult to achieve because single-crystal silicon can- not grow epitaxially on an amorphous substrate. Low tem- perature is also desired to lower the manufacturing cost and ensure the circuit integration.

 

بازرسی جریان گردابی پالسی Pulsed Eddy Current Inspection

Pulsed Eddy Current Inspection of Support Structures

in Steam Generators

بازرسی جریان گردابی پالسی برای سازه های نگهدارنده در ژنراتورهای بخار 

ABSTRACT

Degradation and fouling of support structures in nuclear steam generators (SGs) can lead to SG tube damage and loss of SG efficiency. Inspection and monitoring of support structures combined with preventative maintenance programs can alleviate these effects and extend SG life. Conventional eddy current inspection technologies are extensively used for detecting and sizing indications from wall loss, frets at supports, cracks and other degradation modes in the tubes, as well as assessing the condition of support structures. However, these methods have limited capabilities when more than one degradation mode is present simultaneously, or when combined with fouling. Pulsed eddy current combined with principal components analysis (PCA) was examined for inspection of 15.9 mm (5/8") Alloy-800 tubes and surrounding stainless steel (SS410) support structures. Clear separation of PCA scores associated with tubes from those associated with ferromagnetic SS410 supports permitted measurement of tube-to-support gaps, in either the presence of tube fretting or variation of relative position of the tube within SS410 supports. For concentric tubes, frets could be sized independently of SS410 hole diameter variations, which in other materials could represent support corrosion. Capability to clearly separate scores was attributed to large differences in relaxation times for diffusion of transient fields through the tube compared with diffusion into the ferromagnetic support structure.

 

تاثیر پوشش های محافظ بر خواص مکانیکی سوپر آلیاژها Superalloys

The Effect of Protective Coatings on

the Mechanical Properties of Superalloys

تاثیر پوشش های محافظ بر خواص مکانیکی سوپر آلیاژها

ABSTRACT

COATINGS PROTECT the surface of tur- bine blades from damage caused by high-tem- perature corrosion and thus preserve the struc- tural shape of blades and their mechanical properties for the required time. There are many papers in the technical liter- ature that deal with experimental studies of heat resistance, fatigue strength, and thermal fatigue of coated superalloys. However, the connection between the physical and mechanical properties of protective coatings and their effect on the me- chanical properties of turbine-blade superalloys has not been studied sufficiently well. For thin diffusion coatings, this can be explained by the complexity of the task, both in reproducing the correct composition and in testing the coatings separately from the alloy. However, for these coatings, information on their physical and me- chanical properties is necessary for their proper application and for accurate calculations of coated-blades service lives.