نتایج جستجو برای: آلومینیم 2024
تعداد نتایج: 3927 فیلتر نتایج به سال:
We present results of a sensitive 76 ksec Chandra observation of the young stellar cluster in NGC 2024, lying at a distance of ∼415 pc in the Orion B giant molecular cloud. Previous infrared observations have shown that this remarkable cluster contains several hundred embedded young stars, most of which are still surrounded by circumstellar disks. Thus, it presents a rare opportunity to study X...
In this study, the transitions of land use that occurred in the urban and peripheral areas of Chihuahua City, Mexico, were determined for the period 1989–2014. Landsat TM and OLI scenes, as well as the method of Markov Chains (MC) were used. Grasslands and Shrublands were the land uses that experienced the highest pressures for land use. Grasslands occupied 23.5% of the area in 1989, decreasing...
Aluminum 2024 and 7075 alloys which are widely used in aerospace and marine applications were chosen to investigate their strengthening mechanisms. Using differential thermal analysis (DIA), metallography and tension tests, the best solutionizing conditions were determined to be 500±5°C and 2 hours for 2024 and 480?±5°C and 1 hour for 7075 alloy. Aging was performed in the range of 100 to 200°C...
در این مقاله اثر عملیات پیرسازی دومرحله ای بر خواص مکانیکی (استحکام کششی، استحکام تسلیم، درصد ازدیاد طول نسبی و سختی) بررسی و نتایج حاصل از پیرسازی دومرحله ای با نتایج حاصل از پیرسازی مصنوعی یک مرحله ای و پیرسازی طبیعی در زمان ها و دماهای مختلف مقایسه شده است. پس از انجام عملیات انحلال در دمای 520 درجه سانتی گراد به مدت دو ساعت و تندسرمایش آلیاژ آلومینیم 2024 در دمای محیط، عملیات پیرسازی طبیعی ...
The material flow and microstructural evolution in the friction stir welds of a 6061-Al alloy to itself and of a 6061-Al alloy to 2024-Al alloy plates of 12.7 mm in thickness were studied under different welding conditions. The results showed that plastic deformation, flow, and mechanical mixing of the material exhibit distinct asymmetry characteristics at both sides of the same and dissimilar ...
We conducted wide-field JHKs imaging polarimetry toward NGC 2024, which is a massive star-forming region in the Orion B cloud. We found a prominent and extended polarized nebula over NGC 2024, and constrained the location of illuminating source of the nebula through the analysis of polarization vectors. A massive star, IRS 2b with a spectral type of O8 − B2, is located in the center of the symm...
We determine the distribution of circumstellar disk masses in the young (∼ 0.3 Myr) cluster NGC 2024 by imaging a 2. 5×2. 5 region in λ3mm continuum emission to an RMS noise level of ∼ 0.75 mJy beam with the Owens Valley Millimeter Array. The mosaic encompasses 147 K-band sources as well as the molecular ridge seen previously in dust continuum emission. We detect 10 point-like sources in λ3mm c...
This paper presents a study of moisture absorption-desorption effects in single lap adhesive joints. Experiments were carried out to characterise the moisture uptake of the single part epoxide adhesive, FM73. Tensile testing of single lap joints manufactured from aluminium alloy 2024 T3 and O and FM73 adhesive was carried out after the joints were exposed to different conditioning environments....
Using the imaging polarimeter for the Submillimeter Common User Bolometric Array at the James Clerk Maxwell Telescope, we have detected polarized thermal emission at 850 μm from dust toward three star-forming core systems in the Orion B molecular cloud: NGC 2071, NGC 2024 and LBS 23N (HH 24). The polarization patterns are not indicative of those expected for magnetic fields dominated by a singl...
فورج پره بدلیل هندسه پیچیده قطعه کار و دقت ابعادی بالا، نحوه جریان پیچیده ماده و ضخامت های متغیر و در بعضی موارد بسیار کم آن فرآیندی پیچیده است. فورج همدما مهم ترین روش تولید برای آلیاژهای آلومینیم و بخصوص هندسه های پیچیده می باشد. در مطالعه حاضر پارامترهای موثر در فرآیند فورج همدمای پره فن ژنراتور زیمنس آلیاژ آلومینیم 2024 بررسی شده و نکاتی که در طراحی آن باید در نظر گرفته شود مطرح گردیده است....
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