نتایج جستجو برای: silica sand
تعداد نتایج: 64666 فیلتر نتایج به سال:
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 ...
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...
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, ...
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...
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 ...
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...
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...
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...
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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