Papers by Keyword: Carbonate

Abstract: In this study, Na₂CO₃ solution as a self-healing agent was impregnated in LWA for autonomic self-healing on cracked cementitious material. The results showed that under the joint action of expansive agent, crystalline additive, phosphate and carbonate, the crack area showed a high self-healing efficiency (close to 70%) after curing in the still water 28d. SEM-EDS test results showed that in addition to ettringite and C-S-H/C-A-S-H, there was also a large amount of CaCO₃ crystal in the depths of the crack.

Abstract: The LSGM-carbonate composite electrolyte is a new type of medium and low temperature SOFC electrolyte material, which has great application potential. In this paper, the molten salt infiltration method was used to prepare the LSGM-carbonate composite electrolyte. The results of SEM test proved that the molten salt infiltration method was more appropriate in preparing the LSGM-carbonate composite electrolyte comparing with direct mixing method. The influence of the type and content of pore forming agent was investigated. The result showed that the polymethyl methacrylate (PMMA) had an excellent pore forming performance and could create interconnected pore structures successfully in LSGM matrix. The XRD result indicated that the LSGM-carbonate composite electrolyte showed almost a single LSGM phase and the carbonate remained glass state. Four terminal method was used to measure the conductivity. The result showed that the conductivity of the LSGM-carbonate composite electrolytes was increased by one order of magnitude compared with pure LSGM. The conductivity of LSGM-carbonate composite electrolytes increased firstly and then decreased with the increasing of PMMA. The LSGM-carbonate composite electrolyte prepared by 25 wt.% PMMA addition has the highest conductivity during the whole range of test temperature and reached 0.3 S.cm^-1 at 600°C.

Abstract: In this study, chicken bone was used as starting material for hydroxyapatite (HAp) synthesis. Chicken bone was calcined in electric furnace at 1000°C for 5 hours in order to obtain calcium oxide. Calcium oxide was reacted with aquadest to form calcium dioxide which was used as calcium precursor. Calcium dioxide was reacted with phosphoric acid which was used as phosphorus precursor. This reaction was conducted at pH 10 and reaction temperature was 40°C. The obtained results of this reaction were calcined at 500°C and 900°C for 2 hours and 6 hours. Then it was characterized by using FTIR, XRD and SEM. The increasing of temperature and time of calcination lead to low carbonate content and good morphology. Different result occurs in particle size which increased with increasing temperature and time of calcination. HAp that synthesized from this study had low purity. Best result was obtained in calcination at temperature 900°C and in 6 hours long where crystal size and crystallinity degree from this sample were 63.021 nm and 87.30% respectively.

Abstract: This article is an overview of potential application of wettability modifier to enhance oil recovery in carbonate reservoir. In oil and gas industry, oil recovery can be divided into three stages which are primary recovery, secondary recovery and tertiary recovery. The primary recovery is the initial stages of oil recovery. At this stage, oil was displaced toward production well by natural drive mechanisms that naturally exist in the reservoir. Water is commonly used to enhance oil recovery by injected into the reservoir because of it is commercially available, less expensive and capable to maintain the reservoir pressure. In conclusion, smart water flooding is a new technique to solve the complexity problem of carbonate reservoir by manipulating the salinity and ionic composition in high temperature. Hence, smart water can be an excellent candidate as a displacing fluid in chemical flooding for enhanced the oil recovery (EOR).

Abstract: At room temperature, dehydrating agent, concentrated sulfuric acid (H₂SO₄) was used to form porous carbon (BAC) from bamboo waste shows good properties as CO₂ adsorbent. Selection of nano-CuO supported BAC produce composite materials with high total surface area and smaller pores size composite of 660.8 cm²/g and 2.7 nm. XRD data showed the support data to confirm the hydroxide phase formation as intermediate for carbonate and accelerate the CO₂ chemisorption reaction. Besides, the presence of BAC together with metal oxide can improve the CO₂ interaction physically on the surface and pores resulting the higher adsorption capability of 32.2 cm³ of CO₂ per gram adsorbent. The combination of nano-CuO on BAC become a good adsorbent which can stimulate the CO₂ reduction programme as well as reduce the CO₂ emissions during BAC production.

Abstract: This paper establishes the lithological sequence of different salinization stage through the corresponding relation between the salinity and salt minerals. It develops salt gypsum rock-glauber's salt-gypsiferous mudstone-dolomitein in brine stage, and stratiform limestone-lamina argillaceous limestone/ lime mudstone-stratiform argillaceous limestone in salt water stage and stratiform argillaceous limestone/ lime mudstone-massive lime mudstone/ massive mudstone in brackish water stage. The shale sedimentary evolution model is established, with climate changing from the hot dry to wet, and water from shallow to deep, and salinity from high to low, lithological sequence is gypsum-carbonate-argillaceous limestone - lime mudstone and mudstone.

Abstract: Halimeda is an important reef-building green alga. Scanning electron microscopy (SEM) and energy spectrum tests on green and white Halimeda collected from Shidao Island in the Xisha Islands show that carbonate is predominantly deposited in the cortexes and medullas, especially in the aragonite raphides of them, as the case of calcium carbonate. These modern carbonate sediments are then compared with their ancient counterparts that are collected from Xichen-1 well in the Yongle Atoll, where a large number of Halimeda segments have been recognized in about 100-m-long late Miocene-middle Miocene whole-coring succession. In addition, there are developed great numbers of algal-frame holes, including secondary dissolved pores and intercrystalline pores in the medullas and in aragonites between cysts, which have formed particular network systems and pore throats.

Abstract: A study for optimizing the experimental conditions for the hydrolysis of polyethylene terephthalate (PET) catalyzed by carbonates was performed. The main influence factors of PET microwave hydrolytic reaction, such as the reaction temperature, time and catalyst dosage, were confirmed and these effects on the catalysis of PET microwave hydrolysis were studied in detail. The results showed that the sequence of influence factors was reaction temperature>reaction time> catalyst dosage. The optimal experimental conditions under the catalyst of basic zinc carbonate were that the catalyst dosage, 0.75%; the reaction time, 210 min; the reaction temperature, 200°C.

Abstract: Tetramethyl ammonium hydroxide (TMAH) has wide applications in semiconductor industry, including photoresist development, silica etching (especially Sigma etching), and wafer cleaning, etc. One of the critical areas of the photolithography process is the development of unexposed (negative) or exposed (positive) photoresists without pattern distortion. As a metal free, basic aqueous solution, TMAH is the most common positive photoresist developer providing no metal contaminations. The bath composition, especially the concentration of TMAH, is strictly controlled within the process specifications (~2.2 to 2.4 % (w/w)), since it greatly affects the developing rate and contrast [1]. Traditional monitoring of TMAH concentration does not suffice for the modern needs of a sub-20 nm IC fabrication process. Additional critical parameters include dissolved carbonate and proprietary surfactants.

Abstract: It is well known that the phase diagram plays an important role in exploitation and utilization of salt lake resources. To effectively employ the systems containing lithium and carbonate, the study on phase equilibrium is essential to the comprehensive utilization of the salt lake resources. In this paper, progresses on phase equilibria of salt-water systems containing lithium and carbonate were presented.