نتایج جستجو برای: silica sand

تعداد نتایج: 64666  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم پایه دامغان 1388

اخیراً استفاده از کاتالیزورها و معرف های تثبیت شده روی بسترهای جامد و شرایط بدون حلال گسترش یافته است زیرا چنین معرف هایی فرایندهای خالص سازی را تسهیل می کنند. از اینرو ما می خواهیم کاتالیزور اسیدی جامدی، ساخته شده از سولفوریک اسید جذب شده روی سیلیکاژل (h2so4-silica) وکاربرد آن در تهیه دی هیدروپیریمیدینون ها، تبدیل الکل ها به کربامات های نوع اول مربوطه و محافظت n-boc آمین ها را معرفی کنیم. تهیه ...

Journal: :Jurnal Ilmu Fisika (JIF) 2021

Research on the natural mineral content in Sampang Regency has been conducted, namely Camplong Beach, Nepa and Mandangin Island. The XRF results show that silica sand at a depth of 0.5 m, 1 1.5 m are 54.6%, 53.2%, 57.0%, respectively. shows highest is calcium. calcium 51.7%, 58.3%, 63.0%, Island 94.69%, 94.65%, 94.98%, XRD test SiO2 phase < 94% formed. In 80% For beach with CaCO3 > 90% Th...

Journal: :Journal of environmental quality 2005
S A Bradford M Bettahar

Accurate knowledge of the transport and deposition behavior for pathogenic Cryptosporidium parvum oocysts is needed to assess contamination and protect water resources. Experimental and modeling studies were undertaken to examine the roles of attachment, detachment, and straining on oocyst transport and retention. Saturated column studies were conducted using Ottawa aquifer sands (U.S. Silica, ...

2004
Yujue Wang Fred Cannon

Foundries employ green sand molds, which contain coal, silica sand, clay, water, and core binders. This represents one of the largest non-combustion users of coal. When the coal experiences high temperature during the metal casting process, it undergoes pyrolysis reactions and can generate significant amounts of volatile organic compounds. Some of the compounds are released as hazardous air pol...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2010
Elizabeth A Carter Michael D Hargreaves Terence P Kee Matthew A Pasek Howell G M Edwards

A Raman microspectroscopic study of several fulgurites has been undertaken. A fulgurite is an amorphous mineraloid, a superheated glassy solid that is formed when a lightning bolt hits a sandy or rocky ground and thermal energy is transferred. The Raman spectra revealed several forms of crystalline and fused silica and also the presence of polyaromatic hydrocarbons found in an interfacial zone ...

Journal: :Acta Geotechnica 2021

Coral sand, which is an important filler resource in coastal areas, continuously subjected to repeated waves or traffic loading. In this study, a series of oedometer tests are conducted on coral sand and silica under loading, the results compared. The influence initial density number amplitude loading volumetric deformation, soil stiffness, particle breakage investigated. reveal that deformatio...

2009
Punyapriya Mishra S. K. Acharya

Experiments were carried out to study the effects of impingement angle and particle velocity on the solid particle erosion behavior of Bagasse Fiber Reinforced Polymer Composites (BFRPCs). The erosive wear is evaluated at different impingement angles from 30° to 90° at four different velocities of 48, 70, 82 and 109 m/s. The erodent used is silica sand with the size range 150 – 250 m of irregul...

Journal: :Environmental Health Perspectives 1995
T S Hardy H Weill

Since the International Agency for Research on Cancer labeled crystalline silica a probable carcinogen in 1988, government regulations have required sand and other products to contain warning labels and researchers have attempted to quantitatively assess low-exposure risks. The uncertainties are unlikely to diminish any time soon, and little value exists in calculating such risks, as low exposu...

2015
A. Ibrahim

This work presents the effect of room temperature vulcanized (RTV) silicone rubber coating on cap and pin type porcelain insulator under ac (50Hz) flashover voltage (KV). Describes experimental results obtained for improvement of porcelain insulator removed from 33kV overhead transmission line at Aswan, Egypt after 28 years of service. Also, this study briefly surveys the environmental contamin...

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