Search Results/Filters    

Filters

Year

Banks




Expert Group









Full-Text


Issue Info: 
  • End Date: 

    دی 1369
Measures: 
  • Citations: 

    3
  • Views: 

    239
  • Downloads: 

    0
Keywords: 
Abstract: 

طرح مورد نظر طراحی یک مرکز تلفن دیجیتال «PCM-TDM » و با برنامه از پیش تعیین شده می باشد. ظرفیت این سیستم 88 خط داخلی و 8 خط خارجی می باشد که تا 512 شماره داخلی و 64 خط خارجی قابل گسترش است. ضمنا قابلیت های مختلف مراکز تلفن مدرن در این سیستم پیش بینی شده است که از جمله ارتباطات پیش رفته دیجیتال و نحوه «سیگنالیگ» سیستم «CCITT» را می توان نام برد. این سیستم مجهز به کنسول اپراتور پیش رفته ای است که علاوه بر امور داخلی رسیدگی به تلفن ها، می تواند سیستم را برای امور مختلف برنامه ریزی یا آزمایش کند. مدل های مختلفی برای طراحی و توسعه این سیستم طراحی و نصب گردیده و پیش بینی می شود که در آینده بتوان مراکز بزرگ دیجیتالی را بر اساس مرکز موجود طراحی نمود. در این سیستم منبع تغذیه مجزایی که با ورودی 48 ولت DC و 220 ولت AC کار می کند نصب شده که مجهز به باطری برای پشتیبانی می باشد.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 239

Issue Info: 
  • Year: 

    2014
  • Volume: 

    8
Measures: 
  • Views: 

    167
  • Downloads: 

    127
Abstract: 

IN THIS WORK MATHEMATICAL MODEL OF A ROOM CONSISTING OF A COMPOSITE WALL WAS DEVELOPED. THE WALL INCLUDES TWO BRICK WALL LAYERS WITH AN INTERNAL LAYER OF THIN PHASE CHANGE MATERIAL (PCM). BASED ON ONE DIMENSIONAL DIFFUSION HEAT TRANSFER MODEL, TEMPERATURE VARIATION OF THE THERMAL SYSTEM OF ROOM TO SINUSOIDAL VARIATION OF EXTERNAL WALL TEMPERATURE WAS OBTAINED. SIMULATION OF SUCH A THERMAL SYSTEM PROVIDES ITS WALL TEMPERATURE DISTRIBUTION AND HEAT FLOW THROUGH THE WALLS FOR A COMPLETE DAY. IN THIS STUDY, PERFORMANCE OF THE COMPOSITE WALL AND AN ORDINARY WALL WAS COMPARED. RESULTS SHOWED THAT UPON APPLICATION OF PCM IN WALL, NOT ONLY DECREASED THE CONSUMPTION OF ENERGY FOR SETTING THE INDOOR TEMPERATURE, BUT ALSO FLUCTUATION OF THE INDOOR TEMPERATURE OF WAS REJECTED.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 167

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 127
Writer: 

میری سمیرا

Issue Info: 
  • Year: 

    1394
  • Volume: 

    1
Measures: 
  • Views: 

    783
  • Downloads: 

    0
Abstract: 

لطفا برای مشاهده چکیده به متن کامل (pdf) مراجعه فرمایید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 783

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0
Journal: 

Issue Info: 
  • End Date: 

    خرداد 1370
Measures: 
  • Citations: 

    0
  • Views: 

    417
  • Downloads: 

    0
Keywords: 
Abstract: 

گزارشی که هم اکنون پیش روی شما است حاصل انجام تحقیقات تئوری و عملی بر روی سیستم های PCM می باشد. روند پیشرفت پروژه بر دو اصل استوار بوده است. یک انجام مطالعات زیربنایی بر روی سیستم های PCM و دوم شروع طراحی و ساخت سیستمهای PCM استاندارد تا حد ممکن و با وجود بودجه خیلی کم این پروژه توانستیم کارهای تحقیقاتی خود را فراتر از محدوده تعریف شده برای پروژه پیش ببریم و خوشحالیم که اعلام کنیم که هم اکنون توانایی ساخت سیستم PCM 30 را کاملا داشته و تنها مشکل بر سر راه تحقق آن نبودن بودجه و امکانات مالی می باشد که امیدواریم با مساعدت مسوولان جهاد این مشکل نیز مرتفع شده و بتوانیم قدمی در راه استقلال این کشور برداریم.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 417

Writer: 

عباس-فتحی

Issue Info: 
  • End Date: 

    شهریور 1369
Measures: 
  • Citations: 

    0
  • Views: 

    228
  • Downloads: 

    0
Keywords: 
Abstract: 

این طرح حاوی تحقیقات پایه ای برای ساخت سیستم  PCM سی کاناله است. در عین حال طراحی و ساخت یک سیستم PCM هشت کاناله که به راحتی بتواند به سی کانال توسعه یابد نیز مد نظر است. در نهایت همراه با انجام مطالعات تئوری و پایه ای بر روی سیستم PCM و طراحی تماس قسمت های مربوط به یک سیستم PCM سی کاناله، سیستم PCM هشت کاناله ای ساخته شده است که به راحتی قابلیت گسترش به سی کانال را دارد.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 228

Issue Info: 
  • Year: 

    2020
  • Volume: 

    4
  • Issue: 

    2
  • Pages: 

    14-18
Measures: 
  • Citations: 

    0
  • Views: 

    146
  • Downloads: 

    95
Abstract: 

Thermal energy storage is among the highly efficient approaches to overcome the energy crisis. Using phase change material (PCM) is one of the most effective techniques in thermal energy storage applications. Several types of PCM with distinct characteristics and different ranges of melting and solidification temperature have found their way in various industries. However, commercialized PCMs generally suffer from low thermal conductivity which limits their application. In this study, the effect of adding different weight percentages of various nanoparticles, such as CuO, TiO2, Al2O3 and graphene to paraffin, as a standard PCM, on the improvement of the thermal properties of PCM was investigated. Thermophysical properties and morphology of the nanocomposites, such as phase change temperature and latent heat of melting were characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), and Fourier Transform Infrared Spectroscopy (FT-IR). SEM images display the proper distribution of nanoparticles in phase change material. FTIR results verified the formation of nanocomposites. A comparison between the investigated PCM nanocomposites showed that the nanocomposites containing 2 wt. % TiO2 with the enthalpy of 179. 88 J/g, and 1 wt. % graphene nanocomposite with the enthalpy of 120. 38 J/g had the highest and lowest energy storage capacity compared to paraffin, respectively. The results indicated that Nano-enhanced phase change materials (NEPCMs) could be particularly useful in applications in which temperature control is crucial. The new types of nanocomposites used in this study showed remarkable thermal performance, and they are capable of being used in thermal management applications. © 2020 Journal of Energy Management and Technology.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 146

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 95 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    621
  • Volume: 

    4
  • Issue: 

    2
  • Pages: 

    164-173
Measures: 
  • Citations: 

    0
  • Views: 

    22
  • Downloads: 

    9
Abstract: 

One of the dangers of storing materials in storage tanks is the leakage of materials due to corrosion to the surrounding environment, which in addition to cause damage due to the loss of valuable material and environmental pollution, can lead to accidents. PCM method is one which is used for inspecting pipelines by electromagnetic method. Electromagnetic fields easily pass-through soil, water, asphalt, etc. Therefore, without drilling and through the ground, pipelines are inspected and monitored. By measuring the amount of induced alternating current in its strong magnetic sensors, it is able to detect the current amount in pipelines, the position of sacrificial anodes, the quality of coating, and the location of its defects. In this method, alternating current is used to inspect pipelines. By increasing the frequency of alternating current, the inductive effect of this method increases on foreign structures and adjacent metal structures. In this case, by using different frequencies as well as very low frequencies, they eliminate the impact of adjacent foreign structures on the inspection results.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 22

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 9 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1386
  • Volume: 

    1
Measures: 
  • Views: 

    350
  • Downloads: 

    0
Abstract: 

لطفا برای مشاهده چکیده به متن کامل (PDF) مراجعه فرمایید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 350

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    1
Measures: 
  • Views: 

    4392
  • Downloads: 

    0
Abstract: 

لطفا برای مشاهده چکیده به متن کامل (pdf) مراجعه فرمایید.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 4392

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0
Issue Info: 
  • Year: 

    2017
  • Volume: 

    17
  • Issue: 

    6
  • Pages: 

    117-127
Measures: 
  • Citations: 

    0
  • Views: 

    1161
  • Downloads: 

    0
Abstract: 

High potential regions for using clean and widespread solar energy are suitable choices to apply solar distillation systems. Iran has a large area with exposed solar radiation and also vast salty water sources in the south and north of country, hence and appropriate situation exists for the use of solar stills and solar distillation equipment. Researchers have focused on development and improvement of working solar distillation champers in recent years to benefit from this modern technology in water crisis conditions. In this research, effect of storage of further heat and also using PCM were surveyed when flow turbulators were applied in the spiral heat exchanger and the salty water flow rates were simultaneously changing and it is this which is the novelty of this research. These experiments were carried out in Babol city, which is a wet region with a mild climate in the north of Iran. These tests also were done during a period of one year. The experiment results determined that during cold months (December to April) using PCM has no effect on efficiency of system. But in warm months (May to November) the effect of PCM is more than the effect of stored heated water. The results show that using heat storage and also applying PCM increase the distilled water gain of system up to 7% and 14% respectively. Furthermore, using turbulators can improve system’s water gain by increasing the heat transfer up to 14%. Maximum distilled water gain was equal to 2250 milliliter/ day.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1161

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
litScript
telegram sharing button
whatsapp sharing button
linkedin sharing button
twitter sharing button
email sharing button
email sharing button
email sharing button
sharethis sharing button