Abstract
Soda-based glass samples were fabricated in a laboratory scale using quartz sands that was a by-product of feldspar floatation in Tak Province, northern Thailand, and 25-wt% commercial-grade Na2CO3 as the main compositions. Fe2O3 of 0.1 to 10.0 wt% concentrations was doped into the glass mixture. Well-mixed and dried powders were melted in a ceramic crucible for 4 hr at 1250ºC using an electric furnace. Transparent and bubble-free glass samples were obtained as results. It was found that Fe2O3 dopant turned the otherwise colorless glass to dark brown. Dielectric property and physical properties, such as, color, specific gravity, and refractive index of the glass samples were studied. The samples’ dielectric constant, specific gravity, and refractive index increased with increasing Fe2O3 doping concentration. UV-VIS-NIR and synchrotron-based X-ray absorption spectra were measured and discussed.
Introduction
Chemical composition of glasses showed an important role in determining properties of them. Glass is ordinary contained with three main parts; network former, network modifier and intermediate species which fall somewhere between network former and modifier [1, 2]. Oxide glasses containing transition metal ions are very interesting because of their potential and wide range of applications such as switching and memory devices, transducers, insulators and dielectrics [3, 4], that are widely applied in many fields; information technology, energy and infrared detection [5]. In general, transition metal ions can exist in multivalent states depending upon the base glass composition, melting temperature and time, and pressure conditions [6]. Among these elements, prime attention should be paid to iron [7]. The addition ...
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... a superlene sample holder prior to being loaded into the sample chamber. The x-ray beam was of 1 mm x 10 mm rectangular shape. Energy calibration was achieved with Fu foil standard and the position of the first inflection point was taken at 7112 eV (±0.2 eV). Reference spectra were also collected on pyrite and hematite powders.
Results and discussion
It was found that the colors of the glass samples were changed from colorless to dark brown.
The specific gravity and refractive index were increased with increasing Fe2O3 contents, from 2.5521 to 2.6562 and 1.51 to 1.52, respectively, as detailed in Table 1 and Figure 2 (a and b).
The dielectric constant was increased with increasing Fe2O3 contents, as shown in Figure 2 (c). It was also found that the dielectric constant depend with the frequencies; the higher frequency, the lower dielectric constant.
Kim, Taewoo, Trey L Arnold, Kyle A Leland, Aimee M Morey, Department of Chemistry, USAF Academy, CO 80840
The endothermic melting temperature for Ptx, blank S-SEDDS, physical mixture of Ptx/blank S-SEDDS, and Ptx-loaded S-SEDDS was determined by DSC 2920. Samples were scanned from 30 to 250 °C at a rate of 10 °C /min. In all the cases, an empty pan was used as the reference. XRD patterns of Ptx, blank S-SEDDS, physical mixture of Ptx/blank S-SEDDS and Ptx-loaded S-SEDDS were recorded using an X'Pert PRO Multipurpose X-Ray diffractometer equipped with CuKα radiation (40 kV, 20 mA). The 2θ scanning range was varied from 2° to 50°.
Quartz (SiO2) is the second most abundant mineral on Earth and is of significant uses in both material and Earth sciences. Quartz crystals exist in polymorphs, which mean that the crystal structure of quartz will change depending on the temperature and pressure of the environment that the crystal is in. The crystal will be in its alpha-crystal form when the surrounding temperature and pressure is low. However, when exposed to intense temperature and pressure, it will convert to its beta-crystal form. This paper aims to look at the transition phase of the two different crystal structures using FePO4, a homeotype of quartz. Both quartz and FePO4
This paragraph will compare and discuss the crystal structure and chemistry between quartz (SiO2), iron phosphate (FePO4) and also looking into the α and β phase of FePO4. From the understanding of the given materials and crystal structure of both SiO2 and FePO4, both of the crystal are quartz-type crystal, the crystal arrangement are quite similar except for the difference in structural parameters tilt angle δ and bridging angle θ. This similarly carries on from the fact that both crystals had a α-β transition. However, from figure 2, the transition temperature for SiO2 and FePO4 are dramatically different, where one is at 846K while the other is 980K respectively. This is due to the tilt and bridging angle is lower than SiO2. Also from figure 2, we can show that both SiO2 and FePO4 thermal expansion in α phase are non-linear and control by angular variations and similarly no thermal expansion in β phase due to the lack
Water (125 ml) was added to the solution then cooled in an ice bath for 10 minutes. The brown crystals (2) were collected by vacuum filtration and dried (2.407 g, 5.37 mmol, 90.3%
The molar absorption coefficient can be found in an absorption spectrum. The absorption spectra is generate...
In high school and college many people who have taken chemistry may have learned that there are only four states of matter:solid, liquid, gas, and plasma. Where would glass fall within these states? Most people you ask might say it’s a solid of course. You can touch it and hit it and it will not give way to your hand. It makes up our windows and protects us from weather, so why would it not be a solid? Well surprisingly the state of glass, or the transition of melted glass to a more solid glass, seems to be a very debated subject in the science world. In fact, in Science Magazine’s 125th Anniversary issue which contained the world’s top one hundred science questions yet to be answered, question 22 was, “What is the nature of the glassy state?” and question 21 goes hand in hand, “Is superfluidity possible in a solid?”(Science,2005). Its seems as though glass is a state of its own, between liquid and solid.
The objective of this lab was to identify physical properties as well as chemical and physical changes. This was done by first observing and recording the physical properties of seven different materials. The materials were: Sulfur (S), Iron fillings (Fe), Sodium bicarbonate (NaHCO3), Sucrose (C12H22011), Sand (SiO2), Magnesium (Mg), and Sodium chloride (NaCl). Those seven materials were then placed in a 24 well plate in small quantity’s and the physical properties were recorded. Sulfur was founded to be a powder with a yellow color and insoluble in water. Iron fillings were black, attracted to a magnet and insoluble. Sodium bicarbonate was found as a crystal solid with a white color and was insoluble. Sucrose was a crystal solid with a while
The mixed alkali effect in the glass materials has been the subject of study in the recent years. Many properties of glasses show non linear behaviour of exhibiting a minimum or maximum, as a function of alkali content, if one of the alkali ions is gradually replaced by another alkali keeping total alkali content constant. This behaviour is called mixed alkali effect. The general formula for mixed alkali oxide glass is y[x.A2O + (1-x) B2O] + (1-y) glass former, where A and B are alkalis. The extent of departure from linearity, the direction of variation (positive or negative) depends on the property examined and the glass system. The behavior of mixed alkali effect is independent of glass forming oxides. It is being observed in silicates, borates, phosphates, germanates, tellurites, boro alluminate, alumino silicates, borotellurate etc., glasses. It is also observed that properties related to cationic movement are more sensitive to mixed alkali effect [1-3].
The percent yield was 26%, and the melting point of the product was 170c-172c. According to these results, it can be considered that there are a high range of reactant in the product because the melting point for Ferrocene is 172 and for Acetylferrocene is about 81-83. It is also showed that the product is not pure, and also the TLC was run.
Later we weighed 0.150g of 1:1 ferrocene and acetylferrocene(orange) mixture and we added silica, we mixed it together. This mixture was placed into the column adding solvent not letting it get dry. Immediately we noticed the yellow color traveling down the slurry. When it was close enough to the bottom of the column, it was drained into beaker #1. Then the white part was transfer to beaker #2, which was our trash beaker, this step is necessary to make that part of the orange does not contaminates the yellow part to prevent impurities. At this point 2:8 solvent was over, therefore we used 1:1 solvent which has a higher polarity. Then we drained the orange part to beker
Four solutions were tested an out of the four only one had a color change, meaning that it had alcohol present. This solution was methanol and of course it would produce a color change because methanol is an alcohol. One solution that should have changed color was solution 4, the base-hydrolyzed aspartame, but it did not produce a color change when aqueous ceric ammonium nitrate reagent. Water and fresh aqueous aspartame are not going to produce a color change because there is no alcohol group in there structure.
There is evidence of glass making from as early as 4000 BC. Back then it was mostly used for the coating of stone beads. It was 1500 BC when the first hollow glass container was made. It was made by covering a sand core with a layer of molten glass. It was during the First Century BC that glass blowing became more common. At this time glass was high coloured due to the impurities of the raw materials that were used to make it. The first recorded colourless glass was made in First Century AD. The Romans were one of the most skilled in glass making and held most of the secrets. It wasn’t until the Roman Empire began to fall that the secrets began to leak out into Europe and the Middle East. At this time the greatest reputation for technical skill and artistic ability was held by the Venetians. A far amount of Venetian craftsmen left Italy to set up their own glassworks.
Glass blowing as a career is really unique and creative. People can learn to make all sorts of crazy things and to use their own creativity to its fullest. Glassblowing is the art of shaping melted glass to make decorative objects. It is an area of concentration within the fine arts field at colleges and universities. Glass is an adaptable, old material that is still being explored and understood by everyone from artist to scientist even in this new age.
Fiber optics, in the world of technology, is used to carry voice, data, and video inside these strands of glass. Optical fiber for telecommunications consists of three components: core, cladding and coating. The core is the central region of an optical fiber through which light is transmitted. The core and cladding are manufactured together as a single piece of glass and cannot be separated from one another. The third section is the outer protective coating. This coating is typically an ultraviolet (UV) light-cured acrylic applied during t...