Silicon Dioxide Content Research Articles

Regularities and peculiarities of the synthesis of molecular sieves with pentasil structure

Pentasils can be synthesized with various organic compounds and without them. The nature and form of the raw materials, the composition of the reaction mixtures, and the conditions of the synthesis have an influence on the crystallization process, leading to changes in the structure, the morphology, the phase composition, the dispersion, and the chemical composition of the crystals, the sorption capacity, the strength of the acid sites, and the catalytic activity. Reaction mixtures crystallizing into pentasils have a high silicon dioxide content.

Influence of production factors on the strength of ceramic materials

1. It is experimentally shown that the 95% aluminum oxide-base ceramic has the highest compressive strength among the materials considered, σc=3100 MPa, which is almost 15 and 30% more than the similar characteristics for cast STL-10 pyroceram and 13v technical glass, respectively. 2. The difference between the axial compressive, tensile, and pure bend strengths of specimens cut from sections and parts of chemically resistant porcelain and ceramic VIII produced by forming of a plastic mixture and slip casting in gypsum molds is from 25 to 40%. At the same time the difference between the compressive strength of specimens of ceramic VIII oriented at a right angle in cutting from the nozzle type part produced by slip casting in a gypsum mold reached 60%. 3. The axial compressive strength of the investigated ceramics increases with an increase in aluminum oxide content and decreases with an increase in silicon dioxide content. The bend strength of the ceramics may be increased by 15–80% by selection of the optimum machining conditions and firing temperature of the sections and by decreasing the porosity of the material. 4. The spread in experimental values of the strength of aluminum oxide-base ceramic materials under bending conditions, conditionally characterized by the sample variation coefficient, may be decreased to 8–12% by decreasing the porosity of the material and also by selection of the optimum machining conditions.

Influence of dispersion method on particle size and dissolution of grisgofulvin-silicon dioxide tripurations

AbstractDissolution rate and particle size distribution of griseofulvin were determined after simple blending or solvent deposition using colloidal silicon dioxide. Griseofulvin deaggregation in simple blends and micro-particulate drug dispersion in solvent deposited samples, both determinants of drug dissolution rate, were a function of silicon dioxide content. Solvent deposited samples scored impressively highly initial dissolution rates compared to corresponding simple blends. However, dissolution data thereafter were not encouraging. Drug particle size enlargment in griseofulvin rich samples and incomplete drug recovery from silicon dioxide rich samples were notable drawbacks in solvent deposition systems. Viscosity effects of silicon dioxide dispersion on griseofulvin dissolution were demonstrated. Simple blending with silicon dioxide was recommended as a means of promoting dissolution rate of griseofulvin. Limitation of average particle size data determined by methods which do not discriminate betwe...

Determination of sulphur content in drill core samples by backscattered beta-particles and gamma-ray absorption

A relatively simple method of sulphur determination in drill cores of calcium carbonate matrix is described. The method is based on the combination of measurements of backscattered beta-particles and transmitted low energy gamma-radiation intensities. The transmitted gamma-radiation measurement corrects the errors of sulphur determination caused by the varying strontium sulphate and silicon dioxide content. The method has been tested on 170 samples. It was estimated that the standard deviation of sulphur determination does not exceed 2.5% of sulphur. The apparatus for routine absorption measurement is also described.

Vacuum cleaning of dust in the shops of the glass and ceramic enterprises

showed that the intensity of dust settling Q can be 3.3-8.6 kg/m 2 per day. The thickness of deposition h is equal to 2.5-7.5 nun. The density of dust Pd is 2300-2720 kg/m 3. According to the chemical analysis, the silicon dioxide content in the dust under consideration is 70-75% by weight. With intense recycling of air that is necessary in the industrial premises of the plants under consideration the settled dust is raised and spread over the premises. Besides the harmful effect on human organs, the dust has a bad effect on the state of protective constructions of buildings, adds to the wear of mechanisms, and reduces the natural illuminance. Manual cleaning by brooms and brushes is as inefficient and ineffective as blowing off the dust by compressed air. Moistening or washing off the dust by water eliminates the discharge of dust. However, this method of cleaning can have limited application in glass and ceramic works. The most improved method of cleaning the premises of given factories is the vacuum dust cleaning. It ensures the highest hygienic and economic indices as well as good quality of surface cleaning. The method is free from various disadvantages of the above-mentioned methods. The dust is collected in a special vessel and, where necessary, it can be recycled in the production. The method is applicable for any temperature of air and for cleaning different surfaces and inaccessible places. Vacuum cleaning is carried out by means of mobile vacuum cleaners or central vacuum cleaning installations. The mobile cleaners do not find popularity in the glass and ceramic industry because of the fact that in using them often repeated operations are required while removing dust from bunkers and filters. The mostperfect, efficient, convenient, and reliable are the central vacuum cleaning installations (TsPU)~

Mariner 9 Science Experiments: Preliminary Results

On the basis of data provided by the IR interferometer spectrometer on the Mariner 9 spacecraft, it is suggested that the composition of the Martian dust corresponds approximately to that of rocks of intermediate silicon dioxide content. The large dynamical pole flattening obtained from satellite observations has been confirmed by the Mariner 9 data.

Silicate Spherules from Tunguska Impact Area: Electron Microprobe Analysis

The major oxide composition of four silicate spherules from the area of forest devastated by the explosion of the Tunguska meteorite has been determined by electron microprobe analysis. In general, the spherules have compositions similar to that of igneous glass except for the low iron and the high calcium oxide content of the three spherules that have a low content of silicon dioxide. None of the spherules seem to have compositions similar to the silicate portiof any major meteorite group.

ETIOLOGY OF THE PULMONARY FIBROSES AND MEDICO-LEGAL ASPECTS OF PNEUMONOKONIOSIS

Article1 September 1935ETIOLOGY OF THE PULMONARY FIBROSES AND MEDICO-LEGAL ASPECTS OF PNEUMONOKONIOSISWM. S. MCCANN, M.D., F.A.C.P.WM. S. MCCANN, M.D., F.A.C.P.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-9-3-234 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptThe medico-legal questions which have arisen in connection with the pneumonokonioses are of two kinds: those which come from common law suits for negligence, and those which are connected with workmen's compensation laws. Many of our states have not yet included pneumonokoniosis in their compensation schedules. In these states a furious battle is being fought in the courts, into which medical men are being drawn by both sides. The physician who is suddenly projected into the "no man's land," which is the territory of the expert medical witness, finds himself between two fires. He is faced with ethical problems of...Bibliography1. BALEFRAY WFW: A method for the analysis of dust samples employing x-ray diffraction, Jr. Indust. Hyg., 1935, xvii, 1. Google Scholar2. BOWMANBIANCO PGAJ: Tularemic pneumonia, ANN. INT. MED., 1934, vii, 1491. Google Scholar3. COLLISYULE ELGU: Mortality experience of occupational group exposed to silica dust, compared with that of general population and occupational group exposed to dust not containing silica, Jr. Indust. Hyg., 1933, xv, 395-417. Google Scholar4. FRASERIRVINE DSLG: Statistical account of the incidence and progression of silicosis among the gold miners of the Witwaters Rand, Silicosis, International Labor Office, Geneva, 1930, p. 618. Google Scholar5. GARDNERCUMMINGS LUDE: Reaction to fine and medium sized quartz and aluminum oxide particles; silicotic cirrhosis of liver, Am. Jr. Path., 1933, ix, 751-764. Google Scholar6. GARDNERCUMMINGSDOWD LUDEGR: Experimental inhalation of bituminous coal dust and its effects upon primary tuberculous infection in guinea pigs, Jr. Indust. Hyg., 1933, xv, 456-465. Google Scholar7. HURTADOKALTREIDERFRAYBROOKSMCCANN ANLWWWDWS: Studies of the total pulmonary capacity and its subdivisions. VIII. Observations on cases of pulmonary fibrosis, Jr. Clin. Invest., 1935, xiv, 81. CrossrefGoogle Scholar8. HURTADOKALTREIDERMCCANN ANLWS: Studies of total pulmonary capacity and its subdivisions. IX. Relationship of oxygen saturation and carbon dioxide content of arterial blood, Jr. Clin. Invest., 1935, xiv, 94-105. CrossrefGoogle Scholar9. IRWIN DA: Microincineration as an aid in diagnosis of silicosis, Canad. Med. Assoc. Jr., 1934, xxxi, 140-143. Google Scholar10. IRWIN DA: Histological demonstration of siliceous material by microincineration, Canad. Med. Assoc. Jr., 1934, xxxi, 135-140. Google Scholar11. KLOTZ O: The pathology of pneumonokoniosis: a review, Am. Jr. Med. Sci., 1934, clxxxviii, 418. Google Scholar12. LANZAVANE AJRJ: Prevalence of silicosis in the general population and its effects upon the incidence of tuberculosis, Am. Rev. Tuberc., 1934, xxix, 8-16. Google Scholar13. MCCANNHURTADOKALTREIDERFRAY WSANWW: Estimation of functional disability in pulmonary fibroses, Jr. Am. Med. Assoc., 1934, ciii, 810-815. CrossrefGoogle Scholar14. MCCONNELLFEHNEL WJJW: Health hazards in foundry industry, Jr. Indust. Hyg., 1934, xvi, 227-251. Google Scholar15. MCNALLY WD: Silicon dioxide content of lungs in health and disease, Jr. Am. Med. Assoc., 1933, ci, 584-587. CrossrefGoogle Scholar16. PANCOASTPENDERGRASS HKEP: Roentgenologic aspect of pneumonokoniosis and its differential diagnosis, Jr. Am. Med. Assoc., 1933, ci, 587-591. CrossrefGoogle Scholar17. PROSKESAYERS HORR: Pulmonary infection in pneumonokoniosis; bacteriologic and experimental study, Public Health Rep., 1934, xlix, 839-858. CrossrefGoogle Scholar This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: Rochester, New York*Read at the Philadelphia meeting of the American College of Physicians, April 30, 1935.From the Department of Medicine, University of Rochester, School of Medicine and Dentistry, and the Medical Clinic of the Strong Memorial and Rochester Municipal Hospitals. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 September 1935Volume 9, Issue 3Page: 234-244KeywordsDentistryEtiologyHospital medicinePneumoniaPulmonary fibrosis ePublished: 1 December 2008 Issue Published: 1 September 1935 PDF downloadLoading ...