Search results for: condensed silica fume

Authors: Mohamed Tamer, Wink Michael

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DNA intercalating agents increase the stability of DNA which can be demonstrated by measuring the melting temperature Tm. Tm can be determined in a spectrophotometer in which the cell temperature is increased gradually. The resulting absorption data comes as a sigmoidal curve from which melting temperature can be determined when half of the DNA has denatured. The current study aims to assess DNA intercalating activities of four pure bioactive isoquinoline alkaloids: sanguinarine, berberine, allocryptopine, and chelerythrine which were isolated from Chelidonium majus (Papaveraceae) by repeated silica gel column chromatography, recrystallization and preparative TLC. The isolated compounds were identified by comparing their physical properties and mass spectra with those of the published data. The results showed that sanguiarine is the most active intercalating agent with Tm value of 83.55 ± 0.49 followed by berberine, chelerythrine, and allocryptopine with Tm values 62.58 ± 0.47, 51.38 ± 0.37 and 50.94 ± 0.65, respectively, relative to 49.78 ± 1.05 of bacteriophage DNA alone and 86.09 ± 0.5 for ethidium bromide as a positive control.

Keywords: alkaloids, Chelidonium majus, DNA intercalation, Tm

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Authors: Triem T. Hoang

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Loop heat pipes (LHPs) are two-phase capillary-pumped heat transports. An appropriate working fluid is selected for the intended application temperature range. A closed-loop is evacuated to a high vacuum, back-filled partially with the working fluid, and then hermetically sealed under the fluid own pressure. Heat from a heat source conducts through the evaporator casing to vaporize liquid on the outer surface of the wick structure inside the evaporator. The generated vapor is compelled to vent out of the evaporator and into the vapor line for transport to the condenser assembly. There, heat is removed and rejected to a heat sink to condensed vapor back to liquid. The liquid exits the condenser and travels in the liquid line to return to the evaporator to complete the cycle. The circulation of fluid, and thus the heat transport in the LHP, is accomplished entirely by capillary action. The LHP contains no mechanical moving part to wear out or break down and, therefore possesses, reliability and a long life even without maintenance. In this paper, the author not only attempts to introduce the LHP technology in simplistic terms to those who are not familiar with it but also provides necessary technical information to potential users for the proper design and analysis of the LHP system.

Keywords: two-phase heat transfer, loop heat pipe, capillary pumped technology, thermal-fluid modeling

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Authors: Liang-Yi Lin, Hsunling Bai

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In this work, transition metal (metal= Co, Fe, Ni, Cu, and Mn) modified cerium oxide catalysts supported on mesoporous aluminosilicate particles (Ce/Al-MSPs) were prepared using waste silicate as the precursors through aerosol-assisted flow process, and their catalytic performances were investigated for acetone incineration. Tests on the bimetallic Ce/Al-MSPs and Mn/Al-MSPs and trimetallic Mn-Ce, Fe-Ce, Co-Ce, Ni-Ce, and Cu-Ce/Al-MSPs in the temperature range of 100-300 oC demonstrated that Ce was the main active metal while Mn acted as a suitable promoter in acetone incineration reactions. Among tested catalysts, Mn-Ce/Al-MSPs with a Mn/Ce molar ratio of 2/1 exhibited the highest acetone catalytic activity. Moreover, the synergetic effect was observed for trimetallic Mn-Ce/Al-MSPs on the acetone removal as compared to the bimetallic Ce/Al-MSPs or Mn/Al-MSPs catalysts.

Keywords: acetone, catalytic oxidation, cerium oxide, mesoporous silica

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Authors: Bashir Ahmmad, Kensaku Kanomata, Fumihiko Hirose

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The effect of carbon materials on TiO2 for the photocatalytic hydrogen gas production from water/alcohol mixtures was investigated. Single walled carbon nanotubes (SWNTs), multi walled carbon nanotubes (MWNTs), carbon nanofiber (CNF), fullerene (FLN), graphite (GP), and graphite silica (GS) were used as co-catalysts by directly mixing with TiO2. Drastic synergy effects were found with increase in the amount of hydrogen gas by a factor of ca. 150 and 100 for SWNTs and GS with TiO2, repectively. The order of H2 gas production for these carbon materials was SWNTs > GS >> MWNTs > FLN > CNF > GP. To maximize the hydrogen production from SWNTs/TiO2, various parameters of experimental conditions were changed. Also, a comparison between Pt/TiO2, WNTs/TiO2 and GS/TiO2 was made for the amount of H2 gas production. Finally, the recyclability of SWNTs/TiO2 and GS/TiO2 were tested.

Keywords: photocatalysis, carbon materials, alcohol reforming, hydrogen production, titanium oxide

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Authors: Anton G. Kalmykov, Andrew Yu. Bychkov, Georgy A. Kalmykov

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Nowadays, most oil reserves in Russia and all over the world are hard to recover. That is the reason oil companies are searching for new sources for hydrocarbon production. One of the sources might be high-carbon formations with unconventional reservoirs. Bazhenov formation is a huge source rock formation located in West Siberia, which contains unconventional reservoirs on some of the areas. These reservoirs are formed by secondary processes with low predicting ratio. Only one of five wells is drilled through unconventional reservoirs, in others kerogen has low thermal maturity, and they are of low petroliferous. Therefore, there was a request for tertiary methods for in-situ cracking of kerogen and production of oil. Laboratory experiments of Bazhenov formation rock hydrous pyrolysis were used to investigate features of the oil generation process. Experiments on Bazhenov rocks with a different mineral composition (silica concentration from 15 to 90 wt.%, clays – 5-50 wt.%, carbonates – 0-30 wt.%, kerogen – 1-25 wt.%) and thermal maturity (from immature to late oil window kerogen) were performed in a retort under reservoir conditions. Rock samples of 50 g weight were placed in retort, covered with water and heated to the different temperature varied from 250 to 400°C with the durability of the experiments from several hours to one week. After the experiments, the retort was cooled to room temperature; generated hydrocarbons were extracted with hexane, then separated from the solvent and weighted. The molecular composition of this synthesized oil was then investigated via GC-MS chromatography Characteristics of rock samples after the heating was measured via the Rock-Eval method. It was found, that the amount of synthesized oil and its composition depending on the experimental conditions and composition of rocks. The highest amount of oil was produced at a temperature of 350°C after 12 hours of heating and was up to 12 wt.% of initial organic matter content in the rocks. At the higher temperatures and within longer heating time secondary cracking of generated hydrocarbons occurs, the mass of produced oil is lowering, and the composition contains more hydrocarbons that need to be recovered by catalytical processes. If the temperature is lower than 300°C, the amount of produced oil is too low for the process to be economically effective. It was also found that silica and clay minerals work as catalysts. Selection of heating conditions allows producing synthesized oil with specified composition. Kerogen investigations after heating have shown that thermal maturity increases, but the yield is only up to 35% of the maximum amount of synthetic oil. This yield is the result of gaseous hydrocarbons formation due to secondary cracking and aromatization and coaling of kerogen. Future investigations will allow the increase in the yield of synthetic oil. The results are in a good agreement with theoretical data on kerogen maturation during oil production. Evaluated trends could be tooled up for in-situ oil generation by shale rocks thermal action.

Keywords: Bazhenov formation, fossil fuels, hydropyrolysis, synthetic oil

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Authors: P. Karalis, E. Dotsika, A. Godelitsas, M. Tassi, D. Ignatiadou

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Glass artefacts originated from Northern Greece, dated between 1st and 6th AC, were analyzed for their oxygen isotopic and chemical compositions in order to identify their raw materials provenance. The chemical composition of these glasses is rather heterogeneous although they are all obtained with natron as flux, having both K₂O and MgO contents lower than 1.5 wt%. The majority of these samples have a homogeneous oxygen isotopic composition (𝛿18O= 16‰,), which is equal to or very close to the mean value of “Roman” glass (from about 15‰ to 16.0‰). The rest of the samples present heavily enriched 𝛿18O values that indicate that their raw materials differ from those normally used in Roman and Medieval glass production, and this matches with the possibility of the different origins of these materials. So, all these fragments are soda-lime-silica natron-glass produced from natron, possibly coming from more than one source.

Keywords: ancient glass, provenance of raw materials of ancient glass, roman glass, oxygen isotope analysis in glass

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Authors: Marine Regnier, Pascal Bost, Matthieu Horgnies

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Some of the problems to be solved for the concrete industry are linked to the use of low-reactivity cement, the hardening of concrete under cold-weather and the manufacture of pre-casted concrete without costly heating step. The development of these applications needs to accelerate the hydration kinetics, in order to decrease the setting time and to obtain significant compressive strengths as soon as possible. The mechanisms enhancing the hydration kinetics of alite or Portland cement (e.g. the creation of nucleation sites) were already studied in literature (e.g. by using distinct additions such as titanium dioxide nanoparticles, calcium carbonate fillers, water-soluble polymers, C-S-H, etc.). However, the goal of this study was to establish a clear ranking of the efficiency of several types of additions by using a robust and reproducible methodology based on isothermal calorimetry (performed at 20°C). The cement was a CEM I 52.5N PM-ES (Blaine fineness of 455 m²/kg). To ensure the reproducibility of the experiments and avoid any decrease of the reactivity before use, the cement was stored in waterproof and sealed bags to avoid any contact with moisture and carbon dioxide. The experiments were performed on Portland cement pastes by using a water-to-cement ratio of 0.45, and incorporating different compounds (industrially available or laboratory-synthesized) that were selected according to their main composition and their specific surface area (SSA, calculated using the Brunauer-Emmett-Teller (BET) model and nitrogen adsorption isotherms performed at 77K). The intrinsic effects of (i) dry powders (e.g. fumed silica, activated charcoal, nano-precipitates of calcium carbonate, afwillite germs, nanoparticles of iron and iron oxides , etc.), and (ii) aqueous solutions (e.g. containing calcium chloride, hydrated Portland cement or Master X-SEED 100, etc.) were investigated. The influence of the amount of addition, calculated relatively to the dry extract of each addition compared to cement (and by conserving the same water-to-cement ratio) was also studied. The results demonstrated that the X-SEED®, the hydrated calcium nitrate, the calcium chloride (and, at a minor level, a solution of hydrated Portland cement) were able to accelerate the hydration kinetics of Portland cement, even at low concentration (e.g. 1%wt. of dry extract compared to cement). By using higher rates of additions, the fumed silica, the precipitated calcium carbonate and the titanium dioxide can also accelerate the hydration. In the case of the nano-precipitates of calcium carbonate, a correlation was established between the SSA and the accelerating effect. On the contrary, the nanoparticles of iron or iron oxides, the activated charcoal and the dried crystallised hydrates did not show any accelerating effect. Future experiments will be scheduled to establish the ranking of these additions, in terms of accelerating effect, by using low-reactivity cements and other water to cement ratios.

Keywords: acceleration, hydration kinetics, isothermal calorimetry, Portland cement

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Authors: Hadriana Bansi, Elizabeth Wina, Toto Toharmat

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Acacia villosa is thornless shrub legume which contents high crude protein. However, the utilization of A. villosa as ruminant feed is limited by its secondary compounds. The aim of this article is to find out the maximum of substitution A. villosa in sheep ration. The nutritional evaluation consisted of in vitro two stages, in vivo, and in vitro gas production trials. The secondary compounds of A. villosa also were analyzed. Evaluating digestibility of increasing level of substitution A. villosa replacing Pennisetum purpureum was using in vitro two stages. The substitution of 30% A. villosa was compared to 100% P. purpureum by in vitro gas production technique and in vivo digestibility. The results of two stages in vitro showed that total phenol, condensed tannin, and non-protein amino acid (NPAA) were high. Substitution 15% A. villosa reached the highest digestibility for both dry matter (DM) and crude protein (CP) which were 67% and 86% respectively, but it was shown that DM and CP digestibility of substitution 30% of A. villosa was still high which were 61.82% and 75-67% respectively. The pattern of gas production showed that first 8 hours total gas production substitution of 30% A. villosa was higher than 100% P. purpureum and declined after 10 hours incubation. In vivo trials showed that substitution of 30% A. villosa significantly increased CP intake, CP digestibility, and nitrogen retention. It can be concluded that substitution A. villosa until 30% still gave the good impact even though it has high secondary compounds.

Keywords: Acacia villosa, digestibility, gas production, secondary compounds

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Authors: Kumaran Letchmanan, Shou-Cang Shen, Wai Kiong Ng

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Postoperative implant-associated infections in soft tissues and bones remain a serious complication in orthopaedic surgery, which leads to impaired healing, re-implantation, prolong hospital stay and increase cost. Drug-loaded implants with sustained release of antibiotics at the local site are current research interest to reduce the risk of post-operative infections and osteomyelitis, thus, minimize the need for follow-up care and increase patient comfort. However, the improved drug release of the drug-loaded bone cements is usually accompanied by a loss in mechanical strength, which is critical for weight-bearing bone cement. Recently, more attempts have been undertaken to develop techniques to enhance the antibiotic elution as well as preserve the mechanical properties of the bone cements. The present study investigates the potential influence of addition of mesoporous silica nanoparticles (MSN) on the in vitro drug release kinetics of gentamicin (GTMC), along with the mechanical properties of bone cements. Simplex P was formulated with MSN and loaded with GTMC by direct impregnation. Meanwhile, Simplex P with water soluble poragen (xylitol) and high loading of GTMC as well as commercial bone cement CMW Smartset GHV were used as controls. MSN-formulated bone cements are able to increase the drug release of GTMC by 3-fold with a cumulative release of more than 46% as compared with other control groups. Furthermore, a sustained release could be achieved for two months. The loaded nano-sized MSN with uniform pore channels significantly build up an effective nano-network path in the bone cement facilitates the diffusion and extended release of GTMC. Compared with formulations using xylitol and high GTMC loading, incorporation of MSN shows no detrimental effect on biomechanical properties of the bone cements as no significant changes in the mechanical properties as compared with original bone cement. After drug release for two months, the bending modulus of MSN-formulated bone cements is 4.49 ± 0.75 GPa and the compression strength is 92.7 ± 2.1 MPa (similar to the compression strength of Simplex-P: 93.0 ± 1.2 MPa). The unaffected mechanical properties of MSN-formulated bone cements was due to the unchanged microstructures of bone cement, whereby more than 98% of MSN remains in the matrix and supports the bone cement structures. In contrast, the large portions of extra voids can be observed for the formulations using xylitol and high drug loading after the drug release study, thus caused compressive strength below the ASTM F541 and ISO 5833 minimum of 70 MPa. These results demonstrate the potential applicability of MSN-functionalized poly(methyl methacrylate)-based bone cement as a highly efficient, sustained and local drug delivery system with good mechanical properties.

Keywords: antibiotics, biomechanical properties, bone cement, sustained release

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Authors: Gabriela T. Nakashima, Ana Larissa S. Hansted, Gabriela B. Belini, Carlos R. Sette Jr, Hiroyuki Yamamoto, Fabio M. Yamaji

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The aim of this study was to determine the interference from contaminants in the characterization of sugarcane straw. The sugarcane straw was collected after the harvest and taken to the drying oven, and then it was crushed in the mill type Willey. Analyzes of ash contents and Klason lignin were done in triplicate and high heating value (HHV) in duplicate, according to ASTM standard. The results obtained for the sugarcane straw were 5.29% for ash content, 29.87% for Klason lignin and 17.67 MJ.kg-1 for HHV. Also, the material was analyzed by scanning electron microscope (SEM). The presence of contaminants was observed, such as silica. The high amount of contaminants in the samples may impact the results of analyzes, also raising its values, for example in the Klason lignin content. These contaminants can also adversely affect the quality of the biomass. Even using the standards is important to know what the purpose of the analysis and care mainly of sampling.

Keywords: biomass, bioenergy, residues, solid fuel

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Authors: Paulos Meles Yihdego

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To address the environmental impact of the cement industry and road building waste, the use of chemical stabilizers in conjunction with recycled asphalt and cement components was investigated. The silica-based chemical stabilizers and their potential effects on the base layer stabilized by cement are discussed in this paper. Strength, moisture compaction interaction, and microstructural characteristics are all examined. According to the outcome, using this stabilizer has improved the mechanical properties. The inclusion of chemical stabilizers in the combination, which is responsible for the mixture's improved strength, raised the intensity of the C-S-H (Calcium Silicate Hydrate) gel, according to a microstructural study. The design was demonstrated to be durable by the little ettringites found in the later phases. The application of this stabilizer ensures a strong, eco-friendly, durable base layer.

Keywords: ettringites, microstructure analysis, durability properties, cement stabilized base

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Authors: Dharmana Pradeep, Chandan Kumar Patnaikuni, N. V. S. Venugopal

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Rice Husk Ash (RHA) is a green product contains carbon and also loaded with silica. For the development of durability and strength of any concrete, curing phenomenon shall be very important. In this communication, we reported the exposure of partial replacement of cement with RHA at different percentages of 0%, 5%, 7.5%, 10%, 12.5% and 15% by weight under sodium phosphate curing atmosphere. The mix is designed for M40 grade concrete with the proportions of 1:2.2:3.72. The tests conducted on concrete was a compressive strength, and the specimens were cured in normal water & exposed to the chemical solution for 7, 28 & 56 days. For chemical curing 0.5% & 1% concentrated sodium phosphates were used and were compared with normal concrete strength results. The strength of specimens of 1% sodium phosphate exposure showed that the compressive strength decreased with increase in RHA percentages.

Keywords: rice husk ash, compressive strength, sodium phosphate, curing

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Authors: Adisak Guntida

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Propylene self-metathesis to ethylene and butene was studied over WOx/SiO2 catalysts at 450 °C and atmospheric pressure. The WOx/SiO2 catalysts were prepared by incipient wetness impregnation of ammonium metatungstate aqueous solution. It was found that, adding nano-sized extra supports (SiO2 and TiO2) by physical mixing with the WOx/SiO2 enhanced propylene conversion. The UV-Vis and FT-Raman results revealed that WOx could migrate from the original silica support to the extra support, leading to a better dispersion of WOx. The ICP-OES results also indicate that WOx existed on the extra support. Coke formation was investigated on the catalysts after 10 h time-on-stream by TPO. However, adding nano-sized extra supports led to higher coke formation which may be related to acidity as characterized by NH3-TPD.

Keywords: extra support, nanomaterial, propylene self-metathesis, tungsten oxide

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Authors: P. A. Broodryk, A. F. Van Der Merwe, H. W. J. P. Neomagus

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The production of the clear liquid fertilizer ammonium polyphosphate (APP) is best achieved by the pyrolysis of urea phosphate, as it produces a product that is free from any of the impurities present in the raw phosphoric acid it was made from. This is a multiphase, multi-step reaction that produces carbon dioxide and ammonia as gasses and ammonium polyphosphate as liquid products. The polyphosphate chain length affects the solubility and thus the applicability of the product as liquid fertiliser, thus proper control of the reaction conditions is thus required for the use of this reaction in the production of fertilisers. This study investigates the reaction kinetics of the aforementioned reaction, describing a mathematical model for the kinetics of the reaction along with the accompanying rate constants. The reaction is initially exothermic, producing only carbon dioxide as a gas product and ammonium diphosphate, at higher temperatures the reaction becomes endothermic, producing ammonia gas as an additional by-product and longer chain polyphosphates, which when condensed too far becomes highly water insoluble. The aim of this study was to (i) characterise the pyrolysis reaction of urea phosphate by determining the mechanisms and the associated kinetic constants, and (ii) to determine the optimum conditions for ammonium diphosphate production. A qualitative investigation was also done to find the rate of hydrolysis of APP as this provides an estimate of the shelf life of an APP clear liquid fertiliser solution.

Keywords: ammonium polyphosphate, kinetics, pyrolysis, urea phosphate

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Authors: N. Hatraf, N. Moummi

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The interest in air conditioning using renewable energies is increasing. The thermal energy produced from the solar energy can be converted to useful cooling and heating through the thermochemical or thermophysical processes by using thermally activated energy conversion systems. The ambient air contains so much water that very high dehumidification rates are required. For a continuous dehumidification of the process air, the water adsorbed on the desiccant material has to be removed, which is done by allowing hot air to flow through the desiccant material (regeneration). A solid desiccant cooling system transfers moisture from the inlet air to the silica gel by using two processes: Absorption process and the regeneration process. The main aim of this paper is to study how the dehumidification rate, the generation temperature and many other factors influence the efficiency of a solid desiccant system by using TRNSYS software. The results show that the desiccant system could be used to decrease the humidity rate of the entering air.

Keywords: dehumidification, efficiency, humidity, Trnsys

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Authors: Angga Hidayah Ramadhan, Luciana Andrawina, M. Azani Hasibuan

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Data will be as a core of the decision if it has a good treatment or process, which is process that data into information, and information into knowledge to make a wisdom or decision. Today, many companies have not realize it include XYZ University Admission Directorate as executor of National Admission called Seleksi Masuk Bersama (SMB) that during the time, the workers only uses their feeling to make a decision. Whereas if it done, then that company can analyze the data to make a right decision to get a pin sales from student candidate or registrant that follow SMB as many as possible. Therefore, needs Knowledge Management System (KMS) with Geographic Information System (GIS) use 5C4C that can process that company data becomes more useful and can help make decisions. This information system can process data into information based on the pin sold data with 5C (Contextualized, Categorize, Calculation, Correction, Condensed) and convert information into knowledge with 4C (Comparing, Consequence, Connection, Conversation) that has been several steps until these data can be useful to make easier to take a decision or wisdom, resolve problems, communicate, and quicker to learn to the employees have not experience and also for ease of viewing/visualization based on spatial data that equipped with GIS functionality that can be used to indicate events in each province with indicator that facilitate in this system. The system also have a function to save the tacit on the system then to be proceed into explicit in expert system based on the problems that will be found from the consequences of information. With the system each team can make a decision with same ways, structured, and the important is based on the actual event/data.

Keywords: 5C4C, data, information, knowledge

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Authors: M. A. Hannan, N. Matthias Neisius

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Organophosphorus compound diethyloxymethyl-9-oxa-10-phosphaphenanthrene-10-oxide (DOPAC) was applied on cotton cellulose to impart eco-friendly flame retardant property to it. Here acetal linkage was introduced rather than conventionally used ester linkage to rescue from the undurability problem of flame retardant compound. Some acidic catalysts, sodium dihydrogen phosphate (NaH2PO4), ammonium dihydrogen phosphate (NH4H2PO4) and phosphoric acid (H3PO4) were successfully used to form acetal linkage between the base material and flame retardant compound. Inspiring limiting oxygen index (LOI) value of 22.4 was found after exclusive washing treatment. A good outcome of total heat of combustion (THC) 6.05 KJ/g was found possible during pyrolysis combustion flow calorimetry (PCFC) test of the treated sample. Low temperature dehydration with sufficient amount of char residue (14.89%) was experienced in case of treated sample. In addition, the temperature of peak heat release rate (TPHRR) 343.061°C supported the expected low temperature pyrolysis in condensed phase mechanism. With the consequence of pyrolysis effects, thermogravimetric analysis (TGA) also reported inspiring weight retention% of the treated samples.

Keywords: acetal linkage, char residue, cotton cellulose, flame retardant, loi, low temperature pyrolysis, organophosphorus, THC, THRR

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Authors: H. Elgubbi, A. Mlitan, A. Alzridy

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Ninhydrin is the most well known spray reagent for identification of amino acids. Spring with Ninhydrin as a non-specific reagent is well-known and widely used for its remarkable high sensitivity. Using Ninhydrin reagent alone to detect amino acid on thin layer chromatography (TLA) paper is not advisable due to its lower sensitivity. A new spray reagent, Stannus chloride solution (Sn CL2) has been used to detect amino acids on filtter paper (witman 14) and TLC paper, silica Gel, 60 F254 TLC Aluminium Sheet 20x20cm Merck- Germany. Also, modified TLC pre-staining method was used, which only consisted of 3 steps: spotting, separating and color. The improved method was rapid and inexpensive and the results obtained were clear and reliable. In addition, it is suitable for screening different amino acid.

Keywords: amino acid, ninhydrin, modified ninhydrin reagent, stannus chloride reagent, thin-layer chromatography (TLC), TLC pre-staining

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Authors: Darsh N. Patel, Eric Olson

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Fractals can be found everywhere, whether it be the shape of a leaf or a system of blood vessels. Fractals are used to help study and understand different physical and mathematical processes; however, their artistic nature is also beautiful to simply explore. This project explores fractals generated by a cubically convergent extension to Newton's method. With this iteration as a starting point, a complex plane spanning from -2 to 2 is created with a color wheel mapped onto it. Next, the polynomial whose roots the fractal will generate from is established. From the Fundamental Theorem of Algebra, it is known that any polynomial has as many roots (counted by multiplicity) as its degree. When generating the fractals, each root will receive its own color. The complex plane can then be colored to indicate the basins of attraction that converge to each root. From a computational point of view, this project’s code identifies which points converge to which roots and then obtains fractal images. A zoom path into the fractal was implemented to easily visualize the self-similar structure. This path was obtained by selecting keyframes at different magnifications through which a path is then interpolated. Using parallel processing, many images were generated and condensed into a video. This project illustrates how practical techniques used for scientific visualization can also have an artistic side.

Keywords: fractals, cubic method, Julia programming language, basin of attraction

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Authors: Amber Jamal, Imran Siddiqui, Syed Tanveer Iqbal

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This review is aimed to shed some light on problems constructing a theory of spacetime and geometry in terms of all quantum degrees of freedom called ‘Quantum Gravity’. Such a theory, which is effective at all scales of distances and energies, describes the enigma of the beginning of the Universe, its possible end, and reducing to general relativity at large distances but in a semi-classical approximation. Furthermore, the theory of quantum gravity also describes the Universe as a whole and provides a description of most fundamental questions that have puzzled scientists for decades, such as: what is space, what is time, and what is the fundamental structure of the Universe, is the spacetime discrete, if it is, where does the continuum of spacetime come from at low energies and macroscopic scales and where does it emerge from its fundamentally discrete building blocks? Quantum Field Theory (QFT) is a framework which describes the microscopic properties and dynamics of the basic building blocks of any condensed matter system. In QFT, atoms are quanta of continuous fields. At smaller scales or higher energies, the continuum description of spacetime fails. Therefore, a new description is required in terms of microscopic constituents (atoms or molecules). The objective of this scientific endeavor is to discuss the above-mentioned problems rigorously and to discuss possible way-out of the problems.

Keywords: QFT, quantum degrees of freedom, quantum gravity, semi-classical approximation

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Authors: Abolfazl Bezaatpour, Sahar Khatami

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Fe3O4 nanoparticles were prepared by the co-precipitation method and silica was then coated on the magnetic nanoparticles followed by modification with (3-aminopropyl) trimethoxysilane. Then, dioxomolybdenum(VI) Schiff base complex of N,N′-bis(5-chloromethyl-salicylidine)-1,2-phenylenediamine) was immobilized on the surface of magnetic nanoparticles as a heterogeneous catalyst. The catalyst was identified by scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), X-ray diffraction, IR spectroscopy, diffuse reflectance spectra and atomic absorption spectroscopy techniques. The catalyst shows excellent catalytic activity in epoxidation of olefins using tert-butylhydroperoxide in 1,2-dichloroethane. In this report, the supported complex exhibited 100% selectivity for epoxidation with 100% conversion for cyclooctene. Nanocatalyst can be easily recovered by a magnetic field and reused for subsequent reactions for at least 5 times with less deterioration in catalytic activity.

Keywords: dioxomolybdenum (VI), epoxidation, nanocatalysis, nanoparticles, Schiff base

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Authors: Sabiha Chouchane, Toufik Chouchane, Azzedine Hani

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The wastewater was treated with a natural asorbent “Diatomite” to eliminate chromium three. Diatomite is an element that comes from Sig (west of Algeria). The physicochemical characterization revealed that the diatomite is mainly made up of silica, lime and a lower degree of alumina. The process considered in static regime, at 20°C, an ion stirring speed of 150 rpm, a pH = 4 and a grain diameter of between 100 and 150µm, shows that one gram of diatomite purified can fix according to the Langmuir model up to 39.64 mg/g of chromium with pseudo 1st order kinetics. The pseudo-equilibrium time highlighted is 25 minutes. The affinity between the adsorbent and the adsorbate follows the value of the RL ratio indicates us that the solid used has a good adsorption capacity. The external transport of the metal ions from the solution to the adsorbent seems to be a step controlling the speed of the overall process. On the other hand, internal transport in the pores is not the only limiting mechanism of sorption kinetics. Thermodynamic parameters show that chromium sorption is spontaneous and exothermic with negative entropy.

Keywords: adsorption, diatomite, crIII, wastewater

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Authors: Zin Min Htet, Tikhomirova Irina Nikolaevna, Karpenko Marina A.

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In this paper, thermal insulation materials based on sodium liquid glass with light fillers as foam glass granules with different sizes and wollastonite - M325 (U.S.A production) were studied. Effective mineral thermal insulation materials are in demand in many industries because of their incombustibility and durability. A method for the preparation of such materials based on mechanically foamed sodium liquid glass and light mineral fillers is proposed. The thermal insulation properties depend on the type, amount of filler and on the foaming factor, which is determined by the concentration of the foaming agent. The water resistance of the material is provided by using an additive to neutralize the glass and transfer it to the silica gel.

Keywords: thermal insulation material, sodium liquid glass, foam glass granules, foaming agent, hardener, thermal conductivity, apparent density, compressive strength

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Authors: Burak Yigit Katanalp, Murat Tastan, Perviz Ahmedzade, çIgdem Canbay Turkyilmaz, Emrah Turkyilmaz

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This study evaluated the mechanical and rheological performance of fly ash-based geopolymer at high temperatures. A series of laboratory tests were conducted on neat bitumen and three modified bitumen samples, which incorporated fly ash-based geopolymer at various percentages. Low-calcium fly ash was used as the alumina-silica source. The dynamic shear rheometer and rotational viscometer were employed to determine high-temperature properties, while conventional tests such as penetration and softening point were used to evaluate the physical properties of bitumen. The short-term aging resistance of the samples was assessed using the rolling thin film oven. The results show that geopolymer has a compromising effect on bitumen properties, with improved stiffness, enhanced mechanical strength, and increased thermal susceptibility of the asphalt binder.

Keywords: bitumen, geopolymer, modification, dynamic mechanical analysis

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Authors: Piyali Mukherjee, Jai Prakash Keshri

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Anticipated shortages of raw materials for paper industry have forged the entry of algae as alternatives to wood pulp. Five algal species: Pithophora sp., Lyngbya sp., Hydrodictyon sp., Cladophora sp. and Rhizoclonium sp. were collected from different parts of Burdwan town, West Bengal, India. Their biomass compositional values were determined with respect to eucalyptus wood pulp. Paper characteristics were studied in terms of breaking length, tensile strength, CI index, pH, brightness, recyclability, and durability. Hydrodictyon sp., besides Rhizoclonium sp. and Cladophora sp. were established as the most suitable candidates for paper pulp formulation in terms of high cellulose, hemicelluloses contents and low lignin and silica contents. Paper from pure Hydrodictyon sp. pulp was found to have statistically significant (p < 0.05) improved breaking-length and tensile strength properties compared to that obtained from Lyngbya sp.

Keywords: algae, biomass, paper, pulp, wood

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Authors: Štěpán Hýsek, Petra Gajdačová, Milan Podlena

Abstract:

Annual plants are becoming more and more popular source of lignin and cellulose. In those days a lot of research is carried out in order to evaluate the possibility of utilization of fibres and particles from these plants in composite materials production. These lingo-cellulosic materials seem to be a great alternative to wood, however, due to waxy and silica layers on the surface of these stalks, one additional technological step is needed–erosion of the layers for the purpose of achieving better adhesion between particle and adhesive. In this research, we used several kinds of particle pre-treatment, in order to modify surface properties of these particles. Further, an adhesive was applied to the particles using laboratory blender and board were produced using laboratory press. Both physical and mechanical properties of boards were observed. It was found out that the surface modification of particles had statistically significant effect on properties of produced boards.

Keywords: annual plant, composites, mechanical properties, particleboard

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Authors: Mirna Febriani

Abstract:

Statement of problem. Alginate impression material is an imported material and a dentist always used this material to make impression of teeth and oral cavity tissues. Purpose. The aim of this study was to compare about compressive strength and tear strength of alginate impression material and alginate impression material combined with cassava. Material and methods.Property measured included compressive strength and tear strength. Results.The compressive strength and tear strength of the impression materials tested of a comparable ANSI/ADA standard no.18.The compressive strength and tear strength alginate impression material combined with cassava have lower than the compressive strength and tear strength alginate impression material. The alginate impression material combined with cassava has more water and silica content more decrease than alginate impression material. Conclusions.We concluded that compressive strength and tear strength of alginate impression material combined with cassava has lower than alginate impression material without cassava starch.

Keywords: compressive strength, tear strength, Cassava starch, alginate

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Authors: C. Santhana Krishnan, A. M. Mimi Sakinah, Lakhveer Singh, Zularisam A. Wahid

Abstract:

This study was initiated to evaluate and optimize the conversion of animal fat from tannery wastes into methyl ester. In the pre-treatment stage, animal fats feedstock was hydrolysed and esterified through solid state fermentation (SSF) using Microbacterium species immobilized onto sand silica matrix. After 72 hours of fermentation, predominant esters in the animal fats were found to be with 83.9% conversion rate. Later, esterified animal fats were transesterified at 3 hour reaction time with 1% NaOH (w/v %), 6% methanol to oil ratio (w/v %) to produce 89% conversion rate. C₁₃ NMR revealed long carbon chain in fatty acid methyl esters at 22.2817-31.9727 ppm. Methyl esters of palmitic, stearic, oleic represented the major components in biodiesel.

Keywords: tannery wastes, fatty animal fleshing, trans-esterification, immobilization, solid state fermentation

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Authors: Anna Strąkowska, Marian Zaborski

Abstract:

The studies were focused on POSS application with methylvinylsilicone rubber (MVQ). The obtained results indicate that they can be successfully incorporated into silica-filled rubbers as modifying agents since they enhance cross-link density and improve most properties of the resulting network. It is also worth noting that the incorporation of POSS molecules resulted in stabilizing effect against adverse changes induced by the climatic, ozone or UV ageing of the rubbers. Furthermore, we obtained interesting results of rubbers surface modification using POSS functionalised with halogen groups (Cl, F, and Br). As the results, surface energy of the elastomeric composites and their hydrophobicity increased, barrier properties improved and thermal stability increased as well. Additionally, the studies with silicone rubber and POSS containing acidic and alkaline groups revealed composites with self-healing properties. The observed effects strictly depend on a kind and quantity of functional groups present in angles of POSS cages.

Keywords: elastomeric composites, POSS, properties modyfication, silicone rubber

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Authors: Dewi Selvia Fardhyanti, Astrilia Damayanti

Abstract:

Coal tar is a liquid by-product of coal pyrolysis processes. This liquid oil mixture contains various kind of useful compounds such as benzoic aromatic compounds and phenolic compounds. These compounds are widely used as raw material for insecticides, dyes, medicines, perfumes, coloring matters, and many others. The coal tar was collected by pyrolysis process of coal obtained from PT Kaltim Prima Coal and Arutmin-Kalimantan. The experiments typically occurred at the atmospheric pressure in a laboratory furnace at temperatures ranging from 300 to 550oC with a heating rate of 10oC/min and a holding time of 1 hour at the pyrolysis temperature. Nitrogen gas has been used to obtain the inert condition and to carry the gaseous pyrolysis products. The pyrolysis transformed organic materials into gaseous components, small quantities of liquid, and a solid residue (coke) containing fixed amount of carbon and ash. The composition of gas which is produced from the pyrolysis is carbon monoxide, hydrogen, methane, and other hydrocarbon compounds. The gas was condensed and the liquid containing oil/tar and water was obtained. The Gas Chromatography-Mass Spectroscopy (GC-MS) was used to analyze the coal tar components. The obtained coal tar has the viscosity of 3.12 cp, the density of 2.78 g/cm3, the calorific value of 11,048.44 cal/g, and the molecular weight of 222.67. The analysis result showed that the coal tar contained more than 78 chemical compounds such as benzene, cresol, phenol, xylene, naphtalene, etc. The total phenolic compounds contained in coal tar is 33.25% (PT KPC) and 17.58% (Arutmin-Kalimantan). The total naphtalene compounds contained in coal tar is 14.15% (PT KPC) and 17.13% (Arutmin-Kalimantan).

Keywords: coal tar, pyrolysis, gas chromatography-mass spectroscopy

Procedia PDF Downloads 298