Color marble-like glass-ceramic materials were obtained through thermal treatment of glasses of the system CaO-Al2O3-SiO2 by using natural materials with the introduction of waste materials - ash from thermal power plants (TPP). The melting of the glass batch was in corundum crucibles at 1450oC with an isothermal hold of 60 min. The glasses obtained was fritted in distilled water and dried for 6 hours at 100oC, then completely crushed and divided into fractions with grain size of 0.8 mm, 1.0 mm, 2 mm, 2.5 mm and over 2.5 mm. It was found that the use of ash from TPP lead to higher values of degree of transformation (crystallization) than using base composition. Values of Avramy parameter’s in the range n=1,0 ÷ 1,6 are showed that crystallization of the glass frit is largely heterogeneous and crystal growing starts from the surface. The introduction of ash from TPP to native glasses carry out to significant reduction of energy of crystallization by Ес=289 kJ/mol to Ec=221 kJ/mol. The glass-ceramic materials were obtained through a one stage crystallization - 1050÷1070оС and an isothermal hold of 60 min., colored white, yellow brown to dark brown. The main crystalline phase in glass-ceramics is β-vollastonite with needle habit, size of crystals - ĺ = 40 ÷ 120 μm and d <5 μm in quantities 37 ÷ 42%. As secondary phases depending on the amount of ash have been identified - the anorthite, gehlenite and α-quartz with prismatic habit were appeared. The obtained glass-ceramic materials have a marble-like effect and technical parameters compared with natural granite and marble and have higher values of density, micro hardness, speed grinding, bending strength and chemical resistance. That’s why they can be used in construction such as lining materials.
Production of light-weight porous ceramic media from metakaolin and waste glass
powder with sodium silicate as foaming agent in batch1 and without sodium silicate in
batch 2 was investigated. Different weight percentages of yeast (0.1-0.5) as pore
forming agent have been added to both batches. All samples were formulated by wet
milled, dried, shaped and fired at 700°C for batch 1and at 850°C for batch 2.
Chemical and mineralogical analysis, identification and calculation of crystalline to
amorphous ratio phases by XRD, microstructure and mechanical and physical
properties were investigated to specify the resulting porous article. The predominant
closed porosity is found in batch 1 whereas open pores are prevalent in batch 2. The
size of pores ranges from 3.794mm to 58μm in batch No. 1 and from 67.5 μm to 1.6
μm in batch No. 2 (millimeter to sub-micron) with approximately spherical shape
were found in both batches
The Effect of Dosage and Modulus of Activator on the Strength of Alkali Activ...ijtsrd
In this study, the effect of dosage and modulus of activator on the strength of alkali activated slag and fly ash based geopolymer mortar is studied. Fly ash from Tingyi is used. Blast furnace slag from No 1 Iron and Steel Industry, Pyin Oo Lwin is used. NaOH and Na2SiO3 are used as alkaline activator. Firstly, the physical properties of slag, fly ash and sand are tested. Alkali activated slag mortar is mixed with various proportion of activator. And the tests are made eight times with different activator dosage for slag mortar. Then the test is made once again without activator. Water slag cement ratio of 0.35 is used for this test. Fly ash based geopolymer mortar is mixed various proportion of activator. And the tests are made eight times with different activator dosage for fly ash based geopolymer mortar. Then the test is made once again without activator. Water fly ash ratio of 0.33 is used for this test. For both testing, samples are cured at 85°C for 24 hours and left at room temperature until the day of testing. The samples are tested for 3, 7, 14 and 28 days compressive strength. Then the compressive strength test results obtained from various dosages of activator and without activator are compared. Nyein Nyein Thant | Zin Mar Soe "The Effect of Dosage and Modulus of Activator on the Strength of Alkali Activated Slag and Fly Ash Based on Geopolymer Mortar" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27997.pdfPaper URL: https://www.ijtsrd.com/engineering/civil-engineering/27997/the-effect-of-dosage-and-modulus-of-activator-on-the-strength-of-alkali-activated-slag-and-fly-ash-based-on-geopolymer-mortar/nyein-nyein-thant
Crystallization of synthetic wollastonite prepared from local raw materialsMohammed Obeid
Wollastonite (CaSiO3) has been synthesized by the solid state reaction method at a temperature range of 1050-1250℃ from local raw materials, e.g. silica sand and limestone as well as pure chemicals in the form of carbonate and quartz with and without B2O3 adding as a mineralized. The resulting products are investigated employing XRD and SEM techniques. β-wollastonite was obtained at 1050℃ and transformed to pseudowollastonite (α- CaSiO3) at 1150℃ due to the presence of B2O3. While the pure chemicals failed to give wollastonite at this range of temperature 1050-1150℃. As the temperature increased up to 1400℃, both experimental and standard samples have been melted.
Production of light-weight porous ceramic media from metakaolin and waste glass
powder with sodium silicate as foaming agent in batch1 and without sodium silicate in
batch 2 was investigated. Different weight percentages of yeast (0.1-0.5) as pore
forming agent have been added to both batches. All samples were formulated by wet
milled, dried, shaped and fired at 700°C for batch 1and at 850°C for batch 2.
Chemical and mineralogical analysis, identification and calculation of crystalline to
amorphous ratio phases by XRD, microstructure and mechanical and physical
properties were investigated to specify the resulting porous article. The predominant
closed porosity is found in batch 1 whereas open pores are prevalent in batch 2. The
size of pores ranges from 3.794mm to 58μm in batch No. 1 and from 67.5 μm to 1.6
μm in batch No. 2 (millimeter to sub-micron) with approximately spherical shape
were found in both batches
The Effect of Dosage and Modulus of Activator on the Strength of Alkali Activ...ijtsrd
In this study, the effect of dosage and modulus of activator on the strength of alkali activated slag and fly ash based geopolymer mortar is studied. Fly ash from Tingyi is used. Blast furnace slag from No 1 Iron and Steel Industry, Pyin Oo Lwin is used. NaOH and Na2SiO3 are used as alkaline activator. Firstly, the physical properties of slag, fly ash and sand are tested. Alkali activated slag mortar is mixed with various proportion of activator. And the tests are made eight times with different activator dosage for slag mortar. Then the test is made once again without activator. Water slag cement ratio of 0.35 is used for this test. Fly ash based geopolymer mortar is mixed various proportion of activator. And the tests are made eight times with different activator dosage for fly ash based geopolymer mortar. Then the test is made once again without activator. Water fly ash ratio of 0.33 is used for this test. For both testing, samples are cured at 85°C for 24 hours and left at room temperature until the day of testing. The samples are tested for 3, 7, 14 and 28 days compressive strength. Then the compressive strength test results obtained from various dosages of activator and without activator are compared. Nyein Nyein Thant | Zin Mar Soe "The Effect of Dosage and Modulus of Activator on the Strength of Alkali Activated Slag and Fly Ash Based on Geopolymer Mortar" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27997.pdfPaper URL: https://www.ijtsrd.com/engineering/civil-engineering/27997/the-effect-of-dosage-and-modulus-of-activator-on-the-strength-of-alkali-activated-slag-and-fly-ash-based-on-geopolymer-mortar/nyein-nyein-thant
Crystallization of synthetic wollastonite prepared from local raw materialsMohammed Obeid
Wollastonite (CaSiO3) has been synthesized by the solid state reaction method at a temperature range of 1050-1250℃ from local raw materials, e.g. silica sand and limestone as well as pure chemicals in the form of carbonate and quartz with and without B2O3 adding as a mineralized. The resulting products are investigated employing XRD and SEM techniques. β-wollastonite was obtained at 1050℃ and transformed to pseudowollastonite (α- CaSiO3) at 1150℃ due to the presence of B2O3. While the pure chemicals failed to give wollastonite at this range of temperature 1050-1150℃. As the temperature increased up to 1400℃, both experimental and standard samples have been melted.
We investigate thermoelastic stresses in titanium dioxide films on a sapphire
substrate that arise during thermal annealing. The effect of thermal processes on
thermoelastic stresses in titanium dioxide films has been studied experimentally. The
obtained experimental results are in good agreement with the theoretical calculations
of mechanical stresses in a titanium dioxide film
Nanocomposites are the emerging material in the field of nanotechnology disciplines such as electrical engineering,
mechanical engineering, physics, chemistry, biology and material science. Nanocomposite is a multiphase solid
material, in which atleast one of the phases shows dimensions in the nanometer range (1 nm=10-9 m).
Nanocomposites are multifunctional materials due to their high transparency, electrical conductivity, increased
environmental stability, diffusion constants, mechanical strength, optical quality, heat resistance and recyclability. In
this review Various methods of preparation of Nanocomposirtes will be discusse
TRADITIONAL ingots vs. REMELTED, Comparing Metallurgical ResultsASO Group
As everyone know, remelted ingots are, from a purely metallurgical point of view, preferable to the traditional bottom poured ingots because of a series of reason:
chemical homogeneity
micro inclusions content
ultrasonic results test
absence of segregation
fine and uniform structure.
For a better understanding, we compared characteristics of a remelted ingot around 40tons, with a poly ingot with a similar traversal section of 1500mm and a gross weight near 32tons.
A seminar entitled 'Sol-gel technology for nano-textiles', presented in department of Textile and Apparel Designing, College of Community Science, UAS, Dharawad, by Pratikhya Badanayak and Dr. Jyoti Vastrad.
Influence of reaction medium on morphology and crystallite size of zinc oxidejournal ijrtem
ABSTRACT : Zinc oxide nanoparticles were prepared by reacting zinc chloride and sodium hydroxide in different mediums such as chitosan, poly vinyl alcohol, ethanol and starch. The materials were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) studies, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Elemental analysis was done by energy dispersive X-ray Analysis (EDAX).
KEY WORDS : Nano zinc oxide, morphology, crystallite size
Barium titanate (BaTiO3) doped with rare-earth elements (REE) is used as dielectric in the manufacture of multilayer ceramic capacitors (MLCCs). The most common REE oxide employed as dopant for this application is Y2O3. The behavior of the Y3+ in the BaTiO3 structure depends on its concentration and the sintering conditions, among other factors, which can induce the formation of secondary phases that are a potential cause a detriment to the electrical properties of BaTiO3. The purpose of this work is to perform a phase characterization of BaTiO3 doped with different concentrations of Y2O3, validating its possible contribution to the formation of secondary phases. The role of Y2O3 was evaluated on two kinds of raw materials. The first one is pure BaTiO3 (< 100 ppm Y) and the second kind is a commercial formulation designed for MLCCs known as X7R (-55°C and 125°C, 15% tolerance), which among other elements, already contained 1 wt% of Y2O3. High concentrations of Y2O3 (1% up to 20 wt%) were used aiming to promote structural changes, and even the formation of secondary phases in amounts suitable to be detected by X-ray diffraction. Heat treatment of powder and sintering of ceramics (powder compacted at 2 MPa) were conducted in air (1310°C in air for 3 h, two steps: 1350°C then 1150°C 15 h). A phase transition from tetragonal to a mixture of tetragonal and cubic was observed as Y2O3 concentration increases in the thermally treated powder and in the corresponding ceramics. Commercially formulated powder showed higher densification than pure BaTiO3, and produced cubic structure at higher Y2O3concentrations. The phase Ba6Ti17O40is detected in the 20 wt% Y2O3-doped sample.
We investigate thermoelastic stresses in titanium dioxide films on a sapphire
substrate that arise during thermal annealing. The effect of thermal processes on
thermoelastic stresses in titanium dioxide films has been studied experimentally. The
obtained experimental results are in good agreement with the theoretical calculations
of mechanical stresses in a titanium dioxide film
Nanocomposites are the emerging material in the field of nanotechnology disciplines such as electrical engineering,
mechanical engineering, physics, chemistry, biology and material science. Nanocomposite is a multiphase solid
material, in which atleast one of the phases shows dimensions in the nanometer range (1 nm=10-9 m).
Nanocomposites are multifunctional materials due to their high transparency, electrical conductivity, increased
environmental stability, diffusion constants, mechanical strength, optical quality, heat resistance and recyclability. In
this review Various methods of preparation of Nanocomposirtes will be discusse
TRADITIONAL ingots vs. REMELTED, Comparing Metallurgical ResultsASO Group
As everyone know, remelted ingots are, from a purely metallurgical point of view, preferable to the traditional bottom poured ingots because of a series of reason:
chemical homogeneity
micro inclusions content
ultrasonic results test
absence of segregation
fine and uniform structure.
For a better understanding, we compared characteristics of a remelted ingot around 40tons, with a poly ingot with a similar traversal section of 1500mm and a gross weight near 32tons.
A seminar entitled 'Sol-gel technology for nano-textiles', presented in department of Textile and Apparel Designing, College of Community Science, UAS, Dharawad, by Pratikhya Badanayak and Dr. Jyoti Vastrad.
Influence of reaction medium on morphology and crystallite size of zinc oxidejournal ijrtem
ABSTRACT : Zinc oxide nanoparticles were prepared by reacting zinc chloride and sodium hydroxide in different mediums such as chitosan, poly vinyl alcohol, ethanol and starch. The materials were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) studies, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Elemental analysis was done by energy dispersive X-ray Analysis (EDAX).
KEY WORDS : Nano zinc oxide, morphology, crystallite size
Barium titanate (BaTiO3) doped with rare-earth elements (REE) is used as dielectric in the manufacture of multilayer ceramic capacitors (MLCCs). The most common REE oxide employed as dopant for this application is Y2O3. The behavior of the Y3+ in the BaTiO3 structure depends on its concentration and the sintering conditions, among other factors, which can induce the formation of secondary phases that are a potential cause a detriment to the electrical properties of BaTiO3. The purpose of this work is to perform a phase characterization of BaTiO3 doped with different concentrations of Y2O3, validating its possible contribution to the formation of secondary phases. The role of Y2O3 was evaluated on two kinds of raw materials. The first one is pure BaTiO3 (< 100 ppm Y) and the second kind is a commercial formulation designed for MLCCs known as X7R (-55°C and 125°C, 15% tolerance), which among other elements, already contained 1 wt% of Y2O3. High concentrations of Y2O3 (1% up to 20 wt%) were used aiming to promote structural changes, and even the formation of secondary phases in amounts suitable to be detected by X-ray diffraction. Heat treatment of powder and sintering of ceramics (powder compacted at 2 MPa) were conducted in air (1310°C in air for 3 h, two steps: 1350°C then 1150°C 15 h). A phase transition from tetragonal to a mixture of tetragonal and cubic was observed as Y2O3 concentration increases in the thermally treated powder and in the corresponding ceramics. Commercially formulated powder showed higher densification than pure BaTiO3, and produced cubic structure at higher Y2O3concentrations. The phase Ba6Ti17O40is detected in the 20 wt% Y2O3-doped sample.
Some studies on ceria–zirconia reinforced solvothermally synthesized cordieri...Abhinav Srivastava
Nanostructured cordierite and 12 mol% ceria stabilized zirconia were chemically prepared separately. Pure cordierite was synthesized solvothermally, whereas [(Zr)0.88(Ce)0.12O2] termed as CeSZ was processed with gelation and co-precipitation method. The evolution of crystalline phases and the microstructures have been studied using X-ray diffractometer, and FE-SEM with EDX. Varying contents (0–20 weight%) of CeSZ were then mixed with cordierite to form sample blocks of desired shapes. These nano-composite blocks were fired at 1100–1400 C for a soaking time of 3 h to observe their thermomechanical, micro-structural and physical properties. Results indicate that ceria not only acts as a stabilizer in zirconia ceramics but it also acts as a sintering aid in cordierite formation. CeO2 also improves
compressibility and structural properties of nano-composites. Sintering temperature also plays an important role in the behavior of nano-composite blocks. All properties show a major improvement than previous reported data’s.
CHEMICAL DURABILITY AND CHARACTERIZATION OF THE PHOSPHATE GLASSES CONTAINING ...ijac123
In order to prepare a high quality glass with high water resistance, we investigated chromium iron phosphate glass because of its improved chemical durability. The introduction of chromium in sodiumiron-phosphate glasses is used to compare its effect with iron in inhibition of corrosion. The sodiumchromium-iron phosphate glass of composition 30Fe2O3-xCr2O3-(15-x)Na2O-55P2O5 (mol %),with (0≤x≤4) was produced by melting batches of (99,98% pure) Cr2O3, Fe2O3, Na2CO3, and (NH4)2HPO4 at 1080°C for one hour and pouring the liquid into the bench. The sample was annealed at 650°C for 48h. We have performed the measurement of X-Ray diffraction, and Infra Red spectroscopy. The chemical durability was evaluated by weight losses of glass samples after immersion in hot distilled water (90°C) for 30 days. Weight loss measurements showed a good chemical durability unlike borosilicate glass.
Fundamentals, synthesis and applications of Al2O3-ZrO2 compositesTANDRA MOHANTA
When the word “Ceramic” comes to our mind, we usually associate them with plates, saucers, cups and mugs. But, the word “Ceramic” encompasses more than just the word “plates” or “saucers”. Indeed, ceramic materials are hard and inherently brittle, but this is just the tip of the iceberg. They have multifarious properties and have acquired a status of high technical importance in the field of scientific research. Ceramics are the soul of the modern day’s structural applications owing to their high mechanical and thermal stability under different challenging conditions. They exhibit remarkable properties such as high hardness, high wear resistance, high corrosion resistance, high elastic modulus, high melting point and the ability to retain high strength at elevated temperatures. Alumina (Al2O3) is one such remarkable ceramic material known for its unique optical, mechanical and electrical properties. But the brittle nature of Al2O3 limits its use in certain engineering applications. Therefore, the strength of Al2O3 and Al2O3- based ceramics can be enhanced by tailoring the microstructural design through the application of strategic techniques that may involve secondary phase particle inclusion (such as Zirconia, ZrO2)
AN APPROACH FOR ENERGY CONSERVATION ON PARTIALLY LATERISED KHONDALITE ROCKS U...IAEME Publication
Partially Lateritised Khondalite (PLK) rocks are the bauxite mining waste materials generated during mining and dumped at the mining site, create environmental pollution. These waste
rocks can be utilized as filler materials for different industrial applications after grinding to suitable mesh size. Thermal shock treatment on ore is used for grain boundary breakage and size reduction,due to thermal shock treatment the surface adsorbed gangue minerals also releases and expose new
surface area in the ore. Comminution study is used after this treatment for further reduction in size.
Partially Lateritised Khondalite (PLK) rocks are the bauxite mining waste materials
generated during mining and dumped at the mining site, create environmental pollution. These waste
rocks can be utilized as filler materials for different industrial applications after grinding to suitable
mesh size. Thermal shock treatment on ore is used for grain boundary breakage and size reduction,
due to thermal shock treatment the surface adsorbed gangue minerals also releases and expose new
surface area in the ore. Comminution study is used after this treatment for further reduction in size.
In comminution study, ball mill has good selective grinding performance. This paper deals with the
effect of thermal shock treatment on grinding characteristics of PLK rock and the overall energy
savings achieved. Alumina based filler/ceramic materials were used in different industries. Thermal
shock of the samples was evaluated using water quench test. Surface deterioration level of samples
was monitored by image analysis before and after quenching. A total energy saving of the order of
52.8 % could be achieved when a sample preheated at 1123 K for 60 minutes followed by coldwater
quenching and grinding.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Modifying of Float Glass Surface with Silver Nanoparticles by Ion - Exchangeinventionjournals
In this study we treated float glass samples in melts of silver containing salts. Our aims are to study the processes of Ag nanoparticle formation in order to clarify the most likely mechanism of colour and nanostructuring processes in the modified surface layer. The UV-VIS spectra show an absorption peak around 450 nm as a prove for colloidal silver particle formation. The cut-off wavelength of the transmission varies from 400 to 520 nm. The process of particle formation is studied by SEM and XRD. The structural changes in the glassy matrix are studied using DRIFT spectroscopy. The IR spectra proof that the structure of the glasses was modified mainly by the shift of the main stretching vibration in the 1050 – 1100 cm-1 spectral range. The analysis of the results of spectroscopic and microscopic studies allow conclusions to be drawn on the influence of the ion exchange time (5–60 min), composition of the salt melt (1-5 mol% AgNO3, 95-99 mol% NaNO3) and the additional heat treatment (700 - 900°C, 60 min) on the nanoparticle sizes, optical characteristics and structural changes in the surface layer of the glasses.
Morphologies of c-si Solar cell - Targeting the approach with least light ref...JATIN KUMAR
As the Reflection of Sunlight, falling on the solar cells is an big issue for its performance, this presentation deals with some Morphologies, mostly used these days in industries and some others also which was in trend years before, for c-Si cells.
The objective is to find out the most appropriate technology for Surface texturing either with or without AR coating that can reduce reflection to its minimum possible value.
Although, it is understood that, with best technology, cost also increases. Therefore, it is a quite challenging task at the present time to provide a cost effective surface Morphologies to limit the Panel cost to not to rise much.
One can get full description of metallic glasses which contains history, preparation methods, effects on metallic glasses, properties and application part is also there with diagrams, tables and graphs
Similar to Sinthesis and Properties of Marble-Like Glass-Ceramics Using of Ash from Thermal Power Plants (20)
Scientific Management of Equipment in Medical Innovation LaboratoryScientific Review SR
Aim; To solve the problem of innovation laboratory instrument management and improve laboratory management level. Method; It is necessary to do an excellent job in managing innovative laboratory equipment by improving the equipment management system, functional division management, appointment registration, and strengthening the construction of management teams to guarantee the cultivation of innovation and entrepreneurship capabilities of undergraduates. Results; The number of innovative experimental projects approved and the number of project groups that the laboratory can accept at the same time was increased significantly. The utilization rate of laboratory equipment has increased, and the vacancy rate has decreased. Conclusion; Excellent instrument management can significantly improve the efficiency of scientific research in the innovation laboratory.
Internationalization and Sustainable Operations: A Broad Investigation of Chi...Scientific Review SR
We investigate if internationalization behaviors encourage sustainable operations of China’s manufacturing firms due to their substantial impact on climate change and special governance modes, and organize a heterogeneity test to clarify what kind of internationalization behaviors can robustly influence such operations. We find that firms with abundant assets and heavy-polluting feature are more committed to sustainable operations. Getting close to international sustainability standards, international auditing standards, and international business all improve sustainable operations. Heterogeneity test further shows that compared with international standards, the positive impact of international business on sustainable operation lacks a robustness, which responds to an argument that for one country, international business acts as a double-edged sword. Overall, this paper reveals internationalization as a key indicator significantly influencing economic, ecological, and social spheres in manufacturing sectors of emerging markets, and complying with well-accepted international standards can be significantly embodied in a more optimistic sustainable operations. However, how to deal with international business in a right manner is a research highlight worthy of ongoing discussion. We focus on different types of internationalization behaviors, and this indicator can theoretically inspire future study to dialectically evaluate the role of internationalization in addressing sustainability problems in emerging markets’ pillar industries.
Mechanical Engineering in Ancient Egypt, Part 92: Tomb Inscription During the...Scientific Review SR
This work is based on a previously published hypothesis which proposed that the solid matter of the universe can be represented as a vibrational wave of energy propagating over an ether or matrix through a mechanism that scrambles the degree of duality in matter: x% localized (solid), y% delocalized (wave). The main purpose of this paper is to present a two-dimensional approximation of the three-dimensional structure of the shape of the energy distribution of an atomic orbital to propose a mechanism through which the orbital can be transported as a vibration from a point A to point B in the matrix. This process requires cycles or oscillations of mounting-dismounting-remounting in which what travels from point A to point B is the energy forming the orbital and not the solid matter that it can form. The atomic seven-dimensional f orbital of hydrogen-like atoms is used as a model to show an analogy to the transformations that it can be submitted to when transported over the matrix.
Usability Engineering, Human Computer Interaction and Allied Sciences: With R...Scientific Review SR
Human Computer Interaction is actually responsible for the designing of the computing technologies keeping in mind the aspects of Interaction. Some of the fields viz. Man-Machine Interaction (MMI), User Experience Designing, User Experience Design, Human Centered Designing etc and importantly all these systems and technologies are dedicated to the designing of interface of various tools and systems such as computers, laptops, electronic systems, smart phones etc. Information Technology field is growing rapidly and there are various technologies are increasing viz. Big Data Management, Cloud Computing, Green Computing, Data Science, Internet of Things (IoT), HCI, Usability Engineering etc. Usability Engineering is gaining as a field of study as well and dedicated in creation of the higher usability and user friendliness of the electronic tools and products. In this field few aspects and technologies are most important and emerging viz. Human cognition, behavioral Research Methods, Quantitative techniques etc for the development of usability systems. Designing, implementation, usability even in multimedia material viz. audio-video may also practice in the Usability Engineering and allied fields. Wireframes including few other prototypes are required in maintaining of the better and healthy man and machine interaction. As the field is growing therefore, it is applicable in other sectors and allied areas and among these agriculture is important one. In agricultural sector different applications of information technologies are increasing and among this Usability Engineering and HCI are important one. In pre production and also in post production; directly and indirectly this technology is emerging and growing. This paper talks about the basics of this technologies and also its current and future technologies with reference to academic potentialities of this branch in Agricultural Informatics programs.
Concentration Distribution and Ecological Risk Assessment of Polycyclic Aroma...Scientific Review SR
The ecological risk assessment of 16 USEPA priority polycyclic aromatic hydrocarbon (PAHs) in water and sediments of Kolo creek, Niger Delta Nigeria was assessed the samples were collected from November, 2018 to June, 2019 from seven locations (A-G) along the creek. The samples were extracted using standard methods and analyzed using gas chromatography (model: HP5890 S). The concentrations of the PAHs in the water and sediment samples ranged between 0.000 - 9.239 µ/L and .002 – 374.35µg/Kg respectively. All the compounds analyzed were detected in all the sampling places, even area far from the flow stations. Hence, the urban runoffs, sewage discharges, and agricultural activities are implicated. Four rings hydrocarbon were present in higher concentration when compared to other PAHs in all sampling sites, with benz (a)anthracene having the highest values in both matrixes. Similarly, lower molecular weight (LMW) PAHs were present in lower concentrations in all sampling sites and they are known to exhibit higher lethal toxicity than the larger PAHs. HMW were present in high concentrations than LMW and are persistent in the environment as a result of their increase resistance to oxidation, reduction and vaporization as molecular weight increases. Similarly, The PAFs of the investigated creek is less than 5%, suggesting existences of minor ecological risks that are insignificance. However, the TEQs detected in high molecular weight showed that there is possibility of cancer to those who may be exposed to the bottom sediment. The indices measured in this habitat may put more pressures to the aquatic organisms and cause drastic changes to their ecosystem which may lead to species extinction.
Volume Fractions of Tantalum Carbides Deduced from the Ta Contents in the Mat...Scientific Review SR
Some superalloys for service at high temperature under stresses are strengthened by tantalum carbides. Their creep resistance depends on the quantity of TaC and this is the reason why it is often important to control the volume fraction of these carbides in the microstructure. Metallographic preparation followed by electron imaging and surface fraction measurements by image analysis is a frequent way for that. Another possibility is to deduce the mass fraction of TaC, and after their volume fraction, from the chemical composition of the matrix when the alloys are only double–phased, on the {matrix + TaC} type. In this work three alloys – chemically designed to be made exclusively of matrix and TaC – were elaborated and isothermally exposed to an elevated temperature for a duration long enough to allow the alloys being at their thermodynamic equilibria. The chemical compositions of the alloy and of its matrix were measured and the results allowed evaluating their TaC mass fractions which were converted in volume fractions. The obtained TaC fractions were compared to results issued from thermodynamic calculations. Good agreement was found for the three alloys, and this allowed to exploit the used software and thermodynamic database to explore further the microstructures at the same high temperature, notably to know the conditions on the Co, Ni, Cr, Ta and C contents to keep the {matrix + TaC} structure and to avoid any possible partial melting.
Assessment of the Coliform Bacterial Load of Some Drinking Water Sources in D...Scientific Review SR
Drinking water samples from 5 sachet water companies, 3 boreholes and 2 taps, collected from different locations of Dutse Metropolis of Jigawa State, Nigeria were analysed for coliform bacterial counts using the Membrane Filtration Technique. All the samples contained some amounts of total coliforms, but mostly within permissible levels. Thirty three percent (33%) of the samples from borehole, 60% from sachet water and 100% from the taps contained faecal coliforms, which indicates contamination. Cultures of the faecal coliforms obtained were morphologically identified using the gram-staining procedure and some series of biochemical tests were carried out in order to identify the organisms. The identified organisms were Escherichia coli (E. coli), Klebsiella sp. and Citrobacter sp. Presence of coliforms above the regulatory set standards indicates contamination and un-safeness of the water for drinking. Presence of organisms such as E. coli, Klebsiella sp. and Citrobacter sp. necessitates improvement in monitoring and water hygiene practices to improve the quality of drinking water in the study area.
Bio Inspired Self-Curing Composite: A Leap into Augmented EnactmentScientific Review SR
Relentless progress has been made on composite materials, their manufacturing processes and their structural design in past few decades. Nevertheless, the approval of composite materials in all engineering disciplines is constrained due to its susceptibility to various kinds of defects during manufacturing stage viz porosity, foreign body inclusion, incorrect fiber volume, bonding defect, fiber misalignment, ply misalignment, incorrect curing cycle, wavy fiber, ply cracking, delamination, fiber microstructural defects etc. Hence there was a requirement of techniques to somehow overcome these defects during the service life of composites being used in various structures and equipment. This promising field of research has made great progress over the past several years, but many procedural encounters are still to be overcome, and there exists a great need for focused research to address several areas of concern. On the other hand, nature has materials that have curing potential and repair strategies ensuring their survival. Sustained development in the field will produce new curing chemistries that possess greater stability, faster kinetics. Tailor-made placement of curing agents is dynamic research subject at the cutting edge of self-curing. New bio-imitative curing agents are closely connected to vascular networks. The purpose of this technical paper is to sort the methodology in line with ongoing research efforts in composites. A perspective on current and future self-curing approaches using this biomimetic technique is offered.
Influence of Information and Communication Technology (ICT) in Tourism Sector...Scientific Review SR
Nepal is a country blessed with natural beauty, diverse culture, majestic Himalayas, religious destination which attracts thousands of tourists every year making the tourism industry progressive to flourish. Information Communication Technology (ICT) proves to be an effective tool for strengthening the tourism industry. Thus, the purpose of this research study is to analyze about the past scenario of tourism industry, advent of ICT in tourism industry, positive impacts of ICT in tourism industry through in-depth interview with tourism experts and people who have worked for tourism since decades. This study is a form of qualitative research where narrative inquiry has been selected and the scenario has been analyzed through themes developed from the narratives. The result reveals that the emerging technology brings positive impacts to tourism industry assisting branding, promotion of the country, enhancing networks through communication and easily booking tours. The proper utilization of ICT helps to welcome tourists and to give identity of our country Nepal to the world.
Reinforcement of Bakelite Moulding Powder in Acrylonitrile Butadiene Rubber (...Scientific Review SR
The influences of two phenolic resins, that is, cashew nut oil modified phenol-formaldehyde resin (CN-m-PF) and Bakelite moulding powder (BMP), on properties of carbon black filled acrylonitrile butadiene rubber (NBR) were investigated and compared. Processability, cure characteristics, mechanical properties, thermal ageing resistance, and oil resistance of the NBR filled with various contents of phenolic resins (0-60 phr) were determined. The addition of both resins leads to a prolonged cure time with a greater value of torque difference. Regardless of the resin type, the improvement of compound processability and the enhancement of modulus and hardness of the NBR vulcanisates are observed with increasing resin content. However, many mechanical properties such as tensile strength, elongation at break and abrasion resistance are deteriorated. Thermal ageing resistance of the NBR vulcanisate is slightly improved in the presence of both resins, probably due to the dilution of NBR with the high heat-resistant phenol-formaldehyde resins. Results also disclose that all NBR vulcanisates demonstrate excellent oil resistance, regardless of the resin type and content. At any given resin content, CN-m-PF gives a better processability, higher stiffness and greater mechanical properties than BMP. However, due to its lower cost, BMP can be used to enhance stiffness of NBR vulcanisates without the risk of processing problem.
Toxic Effect of Glyphosate-Pesticide on Lipid Peroxidation Superoxide Dismuta...Scientific Review SR
The oxidative stress indices lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) in juvenile Clarias gariepinus (average weight 200.15 g) exposed to sub - lethal dose 2.40mg/L and 4.98mg/L of glyphosate was investigated over a period of days 1,5,10 and 15 in three replicates. The colorimetric analysis showed increase in lipid peroxidation from 4.55 ±2.14a1 to 12.12± 10.00a1at 2.40mg/L but remain the same at 4.98mg/L (4.55±2.14a1) compared with control (3.03±0.01a1 to 1.51±2.14b1) from day 1 to 15. The SOD activity decreased significantly with time and concentration compared with control. The Catalase activity at day 15 decreased to 0.17±0.05a1 in 2.40mg/L but further increased to 0.28±0.05b1 in 4.98mg/L compared to 0.28±0.02a1 catalase activity as control. The result suggests that glyphosate induce oxidative stress that may overwhelm the antioxidant system in juvenile catfish especially at higher concentrations with long exposure.
Wheeled robots are often utilized for various remote sensing and telerobotic applications because of their ability to navigate through dynamic environments, mostly under the partial control of a human operator. To make these robots capable to traverse through terrains of rough and uneven topography, their driving mechanisms and controllers must be very efficient at producing and controlling large mechanical power with great precision in real-time, however small the robot may be. This paper discusses an approach for designing a quad-wheeled robot, which is wirelessly controlled with a personal computer (PC) by medium-range radio frequency (RF) transceiver, to navigate through unpaved paths with little or no difficulty. An efficient servo-controlled Ackerman steering mechanism and a high-torque driving power-train were developed. The robot’s controller is programmed to receive and respond to RF control signals from the PC to perform the desired motions. The dynamics of the robot’s drivetrain is modeled and analyzed on MATLAB to predict its performances. The robot was tested on various topographies to determine its physical capabilities. Results show that the robot is capable of non-holonomically constrained motions on rough and uneven terrains.
Geometrical Analysis and Design of Tension-Actuated Ackermann Steering System...Scientific Review SR
The tension-actuated steering system is a vehicular steering design that comprises a motorized gear system, pulleys, inelastic string, main steering bar, and a strain gauge. This development is aimed to produce a steering design that could enhance the efficiency of steering systems in quad-wheeled (i.e. four-wheeled) robots. In this work, the steering system of conventional passenger vehicles and existing quad-wheeled robots are reviewed and their technical deficiencies are improved based on cost, power and production factors. Thus, the tension-actuated steering system is proposed as a solution for mechanizing steering functions in quad-wheeled robots. It is expected that this work will stimulate interest and enthusiasm.
A Study of Propensity Score on Influencing Factors of Length of Stay in Hospi...Scientific Review SR
Background: Burns are a global public health problem, which are universal and can happen to anyone. Because the physical functions in children and adults are different, the confounding factors are easy to affect the results of study. Objective: In this study, we aimed to explore influencing factors of the length of hospital stay (LOS) when the confounding factors were excluded by Propensity Score (PS) in children and adults. Methods: Patients hospitalized for burn from 2014 to 2016 were retrieved from the medical record system of a general biggest hospital in Zunyi. A database was established to analyze the influencing factors of LOS between children and adults by the PS. Results A total of 465 children (61.7% males) and 327 (69.7% males) adults were recruited. The average age was 3.61±3.57 years and 42.48±14.76 years in children and adults with burns respectively. Before PS matching, low age and skin grafting were the protective factors for LOS (Hazard Ratio [HR]=0.993 and 0.339). The risk factors of LOS were male (HR=1.234), the burn depth and total body surface area (TBSA), and burn etiology (HR=1.497). After PS matching, only skin grafting (HR=0.080) and treatment within 24 hours (HR=1.865) were the common influencing factors of LOS. Conclusion the confounding factors were excluded by the PS method, and skin grafting was still a protective factor of LOS for both children and adults. The results provide a reference for the promotion of skin grafting to reduce LOS in burn patients.
Concrete is one of the reliable, durable, economical and acceptable construction materials among the building and construction stakeholders worldwide. Performance of concrete could be threatened especially reinforced concrete by some processes such as corrosion, sulfate attack among others. Corrosion of reinforcement in reinforced concrete can be induced by carbonation process. Even though carbonation initiates corrosion, it has been gathered that carbonation could still be of immense benefits to building and construction industries if its mechanism of operation is understudied. This research work has therefore investigated the effect of carbonation on some selected mechanical properties of concrete such as compressive strength, flexural strength, water absorption and weight changes. Concrete cubes and beams of M15 grade with 0.5 % water-cement ratio were prepared and subjected to accelerated carbonation. Their compressive strength, flexural strength, water absorption and weight changes were determined in accordance with the relevant standards. The outcomes show that carbonation improves all the mechanical properties investigated. The use of carbonation can be positively explored in reinforced concrete provided there is adequate nominal cover.
Biogas Synthesis as Means of Solid Waste Management in Kampala, UgandaScientific Review SR
Cattle dung, cooked food waste, and chicken droppings mixed with coffee husks have been used separately and also as mixtures to form anaerobic digestion slurries in a bid to treat to degrade the organic fractions of these wastes and recycle the bio-fertilizer after recovering biogas. Single and mixed substrate slurries evolved significant quantities of methane within 27days together with reduced mass of soil conditioner. The volume of biogas formed in cogeneration mixtures were higher than for single substrate digestion due to the C/N ratio shifting to near 30:1 as a result of mixing. So degradation of organic pollutants was higher in mixed substrate digestion mixtures. Our study yielded average volumes ranging from 315 to 435+ 5.65.mL/L which was in agreement with what is in literature. Digestion of cattle dung, cooked waste foods, and droppings of chicken and mixed substrate slurries using sludge inoculums was very effective in degrading solid waste from homes, thus detoxifying it to bio-fertilizers. Although both single and mixed substrate digestion of waste yielded high enough volumes of biogas; digestion of slurry of mixed organic solid waste substrates is better method of waste management. Digestion of garbage from Kampala should be tested at macro levels at both ambient and mesophilic temperatures. There is need to try out the garbage digestion experiments in the semi-arid towns as well as very cold towns in Uganda.
The Influence of Partial Replacement of Some Selected Pozzolans on the Drying...Scientific Review SR
Concrete is prone to cracking and one of the major causes of cracking is drying shrinkage of the hardened concrete. This research work was carried out to study the influence of partial replacement of some selected pozzolans on the drying shrinkage of concrete. Four pozzolans used in this study, were made to replace cement at various percentages resulting in various concrete mixes. Setting time test was conducted for the various cement mixes using Vicat’s apparatus and drying shrinkage test was done for the concrete test specimens. The results of the setting time indicate that partial replacement of pozzolans with ordinary Portland cement increases both the initial and final setting time of cement as the percentage replacement increases. Similarly, drying shrinkage results show that concrete made with Groundnut Shell Ash (GSA) and Locust Bean Pod Ash (LBA) at 12% replacement will have a stable and better shrinkage resistance than the control at both 56 days and 90 days. Meanwhile, the control concrete gives a better drying shrinkage at 28 days curing. In conclusion, the results show that pozzolanas [Bamboo Leaves Ash (BLA), Locust Bean Pod Ash (LBA), Sugarcane Bagasse Ash (SBA) and Groundnut Shell Ash (GSA)] can successfully replace cement up to 12% without necessarily affecting the shrinkage ability of the produced concrete. It also shows that Groundnut Shell Ash (GSA), Locust Bean Pod Ash (LBA) and Bamboo Leaves Ash (BLA) are more resistance to drying shrinkage than the control.
Study on the Granulation of FLY Ash from Thermal Power StationScientific Review SR
The effect of the type and amount of binding substance on the yield and strength of granules prepared from fly ash was studied. The highest yield of granules was achieved with clayish slip used as binder. The granules obtained are brittle, with compression strength 0,1МРа. The apparent density of the sintered granulates was in the range1200-1500kg/m3 and the total porosity was 55-40%.
Machining Versus Molding Tolerances in Manufacturing Automotive Sealing SystemsScientific Review SR
The automotive industry has been at the forefront of converting traditional metal parts to plastics. The latter surely offer greater design freedom, opportunity for consolidation, fewer assembly operations, reduced secondary finishing, weight reduction, lower total system costs, a range of properties tailored to specific applications, the ability to withstand temperatures, immunity to most chemicals and corrosive environments. They offer processing in many colors, electrical non-conductivity (insulation from electrical shocks), good thermal breaks (“warmth-to-the-touch”), and low sound transmission (tendency to muffle noise). Nonetheless, plastics have only tapped an estimated 15% of their tremendous potential to replace metals. This is particularly to increase with newer high-performance plastics, increasing sophistication in alloying and blending technologies, and use of computer-aided design and engineering (CAD/CAE) systems. The latter enable engineers to visualize complex parts and molding tools more effectively and faster than ever before. This article identifies fundamental steps and requirements to conduct an efficient and successful conversion of metallic parts to plastics, reviewing the replacement design process from concept to production; an under-the-hood rear retainer for Ford Motor Company is detailed as a case study.
A Physical Philosophy for Approaching the True and Then the Beautiful: Princi...Scientific Review SR
Physics demands not only the beautiful but also the true. The true is the first, and the beautiful is the second. The philosophy of physics should emphasize the true and then the beautiful. After reviewing three kind of main hypotheses beyond standard model, and based on experimental and observational evidences, three physical principles and three philosophical rules are suggested, namely P1-action principle, P2-duality principle, P3-equivalence principle, and R1-logic harmony, R2-minimum hypotheses, R3-maximum hopes. It is revealed that there are no supersymmetry and dark sectors because the space and time for the existence of unknown particles resemble impossible.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Sinthesis and Properties of Marble-Like Glass-Ceramics Using of Ash from Thermal Power Plants
1. Scientific Review
ISSN(e): 2412-2599, ISSN(p): 2413-8835
Vol. 5, Issue. 10, pp: 173-178, 2019
URL: https://arpgweb.com/journal/journal/10
DOI: https://doi.org/10.32861/sr.510.173.178
Academic Research Publishing
Group
*Corresponding Author
173
Original Research Open Access
Sinthesis and Properties of Marble-Like Glass-Ceramics Using of Ash from
Thermal Power Plants
Yancho Hristov Hristov*
Department of Material science and technology, Assen Zlatarov University – Bourgas, Bulgaria
Ganka Rumyanova Kolchakova
Department of Material Science and Technology, Assen Zlatarov University – Burgas, Bulgaria
Abstract
Color marble-like glass-ceramic materials were obtained through thermal treatment of glasses of the system CaO-
Al2O3-SiO2 by using natural materials with the introduction of waste materials - ash from thermal power plants
(TPP). The melting of the glass batch was in corundum crucibles at 1450o
C with an isothermal hold of 60 min. The
glasses obtained was fritted in distilled water and dried for 6 hours at 100o
C, then completely crushed and divided
into fractions with grain size of 0.8 mm, 1.0 mm, 2 mm, 2.5 mm and over 2.5 mm. It was found that the use of ash
from TPP lead to higher values of degree of transformation (crystallization) than using base composition. Values of
Avramy parameter‟s in the range n=1,0 † 1,6 are showed that crystallization of the glass frit is largely
heterogeneous and crystal growing starts from the surface. The introduction of ash from TPP to native glasses carry
out to significant reduction of energy of crystallization by Ес=289 kJ/mol to Ec=221 kJ/mol. The glass-ceramic
materials were obtained through a one stage crystallization - 1050÷1070о
С and an isothermal hold of 60 min.,
colored white, yellow brown to dark brown. The main crystalline phase in glass-ceramics is β-vollastonite with
needle habit, size of crystals - ĺ = 40 † 120 μm and d <5 μm in quantities 37 ÷ 42%. As secondary phases depending
on the amount of ash have been identified - the anorthite, gehlenite and α-quartz with prismatic habit were appeared.
The obtained glass-ceramic materials have a marble-like effect and technical parameters compared with natural
granite and marble and have higher values of density, micro hardness, speed grinding, bending strength and chemical
resistance. That‟s why they can be used in construction such as lining materials.
Keywords: Glass-ceramic; Crystallization; Crystal growing; Marble-like effect.
CC BY: Creative Commons Attribution License 4.0
1. Introduction
Glass-ceramics, intended for building applications, constitute an undoubtedly well-developed and widespread
way to absorb glasses obtained from the treatment of several wastes. In addition to the environmental advantage of
immobilizing wastes into materials with a generally high chemical resistance (like glasses), a certain economic
benefit may be found in entering the large market of construction materials. The first and most important example
was certainly that of Russian Slagsitalls, developed as early as the 1960s, by employing several slags of ferrous and
non-ferrous metallurgy, ashes and wastes from mining and chemical industries [1, 2]. Lately, several combinations
of wastes have been proposed [3-5], sometimes leading to materials with excellent properties [6].
Conventional glass-ceramics start from a two-step thermal treatment of nucleation and crystal growth. Although
undoubtedly widespread, this route presents some disadvantages: the treatment is quite difficult and expensive, and
sometimes particularly slow, so that catalysts (TiO2, Cr2O3, etc.) are needed [1, 2]. In addition, the removal of
defects (like gas bubbles) in the parent glass is essential for the achievement of strong glass ceramics, so that long
fining times are required.
A secondary glass-ceramics manufacturing route, that of sintered glass-ceramics, has been established since the
1960s. Finely powdered glass is generally pressed and sintered, the crystallization occurring together with
densification [7-9]. Since free glass surfaces are preferred sites for devitrification, crystallization may occur without
catalysts, especially for small grains [7], thus configuring a „„surface mechanism‟‟. The sintering approach may lead
to a pleasant „„marble-like‟‟ appearance of the glass-ceramics, much superior to that of Slagsitalls.
Commercial examples of this approach are the wollastonite-based „„Neoparies‟‟, developed in Japan since 1970s
[1, 2]. Sintered pyroxene-based glass-ceramics from cheaper and more accessible raw materials has been developed,
in Bulgaria [10] and in Italy [11-13], since the early 1990s. The parent glass being provided in powdered form, long
fining times are not needed, thus drastically reducing the costs of preliminary glass-making; in addition, very limited
processing times may be advantageous in avoiding the volatilisation of dangerous oxides (like those of heavy metals)
which may be dissolved in glasses when obtained from wastes. Recently, the Kingdom of Saudi Arabia has started
investi-gating the use of its local resources for this purpose, withrelated achievements being seen in the glass–
ceramics andceramics fields [14, 15].
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174
2. Material and Method
The chemical composition of the employed waste and natural resources is available in Tables 1 and 2. The waste
were mixed in the proportion 0%–30%–50% by weight.
Table-1. Chemical composition of the starting waste and natural products
Oxide Ash of TPP Lime stone Sand Feldspar
SiO2 47.41 0.30 99.83 69.98
Al2O3 19.47 0.32 0.12 18.02
CaO 7.31 52.54 - 0.78
Na2O 0.67 - - 9.87
K2O 2.21 - - 0.15
MgO 2.73 1.63 - 0.84
MnO 0.12 - - -
Fe2O3 12.04 0.06 0.03 0.15
TiO2 1.04 0.01 0.02 0.21
P2O5 0.11 - - -
SO3 1.46 - - -
L.O.I (1100o
C) 5.43 45.14 - -
Table-2. Oxides included in the initial glasses
Oxide GPR-0 GPR-30 GPR-50
SiO2 58.68 56.46 53.79
Al2O3 6.98 6.79 11.10
CaO 16.89 16.21 12.80
R2O 4.98 4.46 3.47
MgO 0.58 1.24 1.75
MnO - 0.03 0.05
Fe2O3 0.07 3.54 5.76
TiO2 - 0.30 0.55
P2O5 - 0.03 0.05
B2O3 0.99 0.96 0.91
BaO 3.95 3.77 3.71
ZnO 6.39 6.18 6.06
Sb2O3 0.49 - -
The particular combination was chosen in order to approach the composition of wollastonite-based
„„Neoparies‟‟ [1]; the high content of alkali, with respect to ordinary wollastonite-based glass-ceramics was
compensated by a remarkable amount of alumina, in order to determine alumino-silicate secondary phases.
Melting of mixtures is held in high temperature oven type Naber 2 HT 16/R17 with rate of temperature rise
about 300о
С/h. Upon reaching the maximum temperature, one hour isothermal soaking is held which is needed of
mixing and degassing of the melt in the crucibles. After isothermal soaking dishes are removed and fused glass with
low viscosity is poured into a container with cold water.
Glasses, not including defects were obtained by melting of blends at the following time- temperature conditions:
- temperature 1500°C, isothermal soaking - 60 min.
The degree of the phase transformation, Avrami‟s parameter and activation energy of crystallization are
determined by isothermal method by heat treatment of initial glass in the temperature range 1000 ÷ 1070о
С at
different times of isothermal hold (20÷540min.).
The scanning electron micrographs (SEM) were taken using scanning electron microscope Karl Zeiess Yena
(Germany) in regime of secondary electrons and acceleration of 30 kV
The X-ray analyses were carried out by the method of powder diffraction using X-ray apparatus D2 Phaser
(Germany) with CuKα radiation (30kV, 10mA), Ni filter. The X-ray diffraction scanning angle is from 10° to 60°.
Glass frit is subjected to heat treatment as follows: GP0 – 1070о
С/60min., GP1-30 and GP2-50 1050о
С–60 min.
Micro hardness was determined by the Vickers method of PMT-3 apparatus using samples in the shape of plate
(20 x 20 mm) with polished surfaces.
The speed of smoothing of glasses is determined by using the polished machine "Joke".
Determination of the chemical resistance. Glass-ceramics grains sized 0,40 – 0,50 mm were used for the
determination of their chemical resistance, measured by the weight difference before and after 1h treatment with
0,01n HCl and 0,01n NaOH (at 100°C).
3. Results and Discusion
To explain the kinetics of crystallization of super cooled melts the so-called Avrami equation usually is used [2,
16].
3. Scientific Review
175
α (τ) = 1 - exp(-gI0Un-1
τ n
) (1)
where α(τ) is degree of transformation at time τ, g is a shape constant, Io is the rate of steady-state nucleation, U
is the rate of crystal growth and n is a integer number which depends on the growth direction numbers, the
mechanisms of nucleation and crystal growth.
By taking the logarithms of “(1)” twice, the value of the Avrami constant, n, may be calculated by the slope of
the experimental curve.
In the case of crystals growth from a previously formed constant number of nuclei the Avrami constant only
depends on the crystallization growth. In this case, using isothermal results obtained at different temperatures, the
activation energy of crystal growth, Ec, can be evaluated assuming an Arrhenious temperature dependence, i.e.
U = Uo exp [-Ec/(RT)], “(1)” can be rewritten as:
ln τα = Ec(RT) - In (const Uon
) /n - [ln - ln(1 - α)]/n (2)
where τa is the time, corresponding to a certain value of α.
If the logarithm of τa is plotted against 1/T, the slope gives Ec/R value.
As previously demonstrated [17], the degree of the phase transformation can be evaluated by using density
measurements, through the following equation:
α =[(ρ χ(τ)
-
ρg) ρ x(tot)] / {ρ x(tot)
-
ρg) ρ x(τ)] (3)
where ρg is the density of the initial glass, ρχ(τ) is the density at time τ and ρx(tot) is the maximum density at the
end of the crystallization process.
The wt. % crystal phase formed, x, can be evaluated through the relation [17]:
x = 100(1/ρg -1/ ρgc) /(1/ρ g(c) - 1/ρc) (4)
In this case ρgc is the density of the glass-ceramic, ρc is the density of the crystal phase formed and the ρg(c) is
the density of a glass, having the same composition as the crystal phase formed.
Figure-1. Degree of transformation as a function of time at constant temperature for heat-treated glasses
The degree of the phase transformation (α) is calculated using equation (3) The pycnometer was used for
determining the density of heat-treated glass at a constant temperature for different times. Figure 1 shows the levels
of transformation as a function of time at a constant temperature.
By plotting the graph ln (-ln (1-α)) as of the services of the ln τ can be obtained Avrami‟s parameter (n) of slope of
the experimental linear regression. Figure 2 shows the values of n obtained under different thermal glasses. Values
of n for GPR-0, GPR-30 and GPR- 50 in the range 1.0 - 1.3 correspond to a single dimensional of crystal growth
mechanism [2, 18].
The activation energy of crystallization was calculated by equation (2) using isothermal results obtained under
different temperature of glass thermal treatment.
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176
Fig-2. Avrami‟s parameter at different temperatures of thermal treatment
The activation energy of crystallization was calculated from the slope of the curve obtained by plotting the
dependence of ln τα as a function of 1 / T (Fig. 3).
Figure-3. Activating energy of crystallization determined by isothermal method
Figure-4. XRD spectra of glass-ceramics
5. Scientific Review
177
By introducing a certain percentage of ash to the main glass Ea decreased from 289 to 221 kJ / mol, which is
probably due to the formation of crystalline phases with different phase composition.
The different crystalline phases developed in heat treated samples were identified by X-ray diffraction (XRD)
analysis. The results are shown in figure 4. The main crystalline phase in heat-treated samples appears β-wollastonite
(CaSIO2), as a secondary – anorthite (Ca(Al2Si2O8)), gehlenite (Ca2Al(Al(SiO7)) and α-quartz (SiO2) .
Samples‟ structure was determined by SEM (Fig. 5). There are two types of crystals - needle (wollastonite), and
prismatic (anorthite, gehlenite and α-quartz) having been primarily wollastonite type. By increasing the amount of
ash number of crystals grow but reduces their size from 120 to 40μm и d <5 μm.
Figure-5. SEM of glass-ceramics
Figure-6. Synthesized samples
The total amount of crystalline phases formed, calculated by equation (4) in thermal glasses GPR-0, GPR-30
and GPR-50 is respectively 39, 46 and 51%. The amount of the forming crystal phase β-vollastonite defined by
source [19] end for GPR-0, GPR-30 and GPR-50 is 37, 39 and 42%.
The samples obtained were studied for their main physicochemical properties - density, micro hardness, smoothing
hardness, chemical resistance. The results obtained are presented in Table 3. Synthesized ceramic materials - cut and
polished, resemble the natural appearance of marble and granite (Fig. 6)
6. Scientific Review
178
Table-3. The properties of the glass-ceramics and natural products
Compo-
sition
Density
g /cm3
Micro
hardness,
МРа
Smoothing
hardness
х103
, kg/m2
s
Chemical
resistance
With 0,01 nHCl With 0,01 nNaON
GPR-0 2.83 4620 8.96 1.25 0.41
GPR-30 2.84 5140 7.34 1.31 0.48
GPR-50 2.85 5790 2.95 1.86 0.52
Marble 2.58 2100 14.20 3.57 2.53
Granite 2.72 4800 10.62 3.26 2.11
4. Conclusion
Three kinds of glass compositions were developed for the synthesis of glass- ceramics, using natural products,
as well as waste materials – coal ash from thermal power plants.
The introduction of ash from TPP to native glasses carry out to significant reduction of energy of crystallization by
Ес=289 kJ/mol to Ec=221 kJ/mol.
The main crystalline phase in glass-ceramics is β-vollastonite in quantities 37 ÷ 42%. As secondary phases
depending on the amount of ash have been identified - the anorthite, gehlenite and α-quartz. The phase composition,
structures and some of the most important properties of the glass ceramic samples were determined. The obtained
glass-ceramic materials have a marble-like effect. It was proved that marble – like surface of glass-ceramics is due to
the residual glass-phase and the presence of needle-like crystals oriented to the inside surface of the glass. Those
materials could be used as a wall-covering material in building.
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