Defect and Diffusion Forum Vol. 394

Abstract: In recent years, the movement that banning the sale of gasoline cars and diesel vehiclesespecially in Europe and allowing only electric cars for passenger’s cars has been accelerated. Forexamples, Germany’s federal council, the Bundesrat, has passed a resolution calling for a ban oncombustion engine cars by 2030. If the ban were to go through, German citizens would only bepermitted to purchase electric or hydrogen-fueled cars. In Norway, until 2025 there is a movement tolegislation prohibiting the registration of new cars for passenger car gasoline and diesel cars.Beginning in 2025 in the Netherlands, a bill to prohibit the sale of new cars for gasoline and dieselvehicles was submitted to Congress. Under the circumstances, the growing demand for light weightproducts for automotive industries has been increased due to global trend of environmentalpreservation. Although requires of magnesium has risen dramatically, production of magnesium alloysheet remains still at a very low level in practical use. The aim of the study is to establish a guidelinefor roll design in the roll forming of wrought magnesium alloys to extend practical use of roll formedproducts of wrought magnesium alloys. A three-dimensional elasto-plastic analysis by finite elementmethod has been conducted to express exact roll forming behavior of wrought magnesium alloys thathave different stress-strain curves in tension and compression. A simple V-sections were formed by atandem six stands roll forming machine to demonstrate effectiveness of the simulation methods withdifferent stress-strain curves in the case of tension and compression. Also, spring back analysis hasbeen performed to investigate exact cold roll forming phenomenon for wrought magnesium alloysheets.

Abstract: Fracturing proppant is an important material for hydraulic fracturing, and its performancehas an important impact on the fracturing effect and the fracturing life of oil and gas wells. On thepremise of satisfying the reservoir reconstruction requirement, optimizing the proppant with the besteconomic benefit can reduce the cost of the fracturing operation. The flow conductivity and brokenrate of common proppants are tested to obtain the performance boundaries. Based on the proppantevaluation, according to the selection method, the optimal proppant type for different formationpressures can be selected to maximize economic benefits.

Abstract: In this paper, the relationship between the components of heavy oil wastewater and thesurface wettability of coagulation particles were studied. The effects of cations (Ca2+, Mg2+, Fe2+,Fe3+), oil content and pH on wettability of coagulated particles surface in heavy oil wastewater werestudied by measuring the contact Angle, and the possible mechanism was discussed. It was foundthat the contact Angle decreased with the increase of pH value. The change of oil content isnegatively correlated with the contact Angle. Surface wettability of coagulated particles arecorrelated with cationic concentration in sewage and standard electrode potential. When cationicconcentration is less than 500 mg/L, surface wettability is positively correlated with standardelectrode potential. When cationic concentration is more than 1000 mg/L, surface wettability ismainly related to the total amount of cationic ions in sewage.

Abstract: Molecular dynamics simulation was used to investigate two models of aqueous solution ofcalcium carbonate system between 283K and 373K. The diffusion coefficients of water moleculesdemonstrated that both the electropositive surface (110) on Model-I and neutral surface (104) onModel-II showed interaction with the water molecules, and the surface (110) exhibited strongerelectrostatic interaction with water molecules than the latter, besides obvious anomaly appeared near343K on Model-I. On the other hand, surface (110) exhibited anomalous influences on Ca2+ andCO32- ions near 313K and 343K on Model-I, and only a broad anomaly on CO32- ions near 343K onModel-II. The binding energies between surface (110) / (104) and Ca2+ /CO32- ions demonstrated thatthe surface (104)were more favorable for the growth of the new crystal but weak for the diffusion.

Abstract: In this study, the characteristics of WO3 prepared with acidic solution were analyzed. The acidic solution was prepared by using hydrochloric acid and sulfuric acid as the solutions to be added during the hydrothermal synthesis process. SEM, XRD and electrochemical characteristics tests were performed based on the prepared samples. Samples prepared in hydrochloric acid (W1) solution can identify platelet crystals and nanospheres, and samples made from sulfuric acid (W2) solutions can identify nanospheres and nanocubes. From the XRD data, it was confirmed that all of the diffraction peaks had a hexagonal phase. Electrochemical properties showed good rate capability of W1 samples but low capacitance and W2 samples showed relatively high capacitances.

Abstract: Natural biopolymers were studied for their possible role as biodegradable fillers forlow-density polyethylene (LDPE) films. LDPE/biopolymer blends and films were prepared andcharacterized by the melt flow index (MFI) and tensile test. The addition of biopolymer to LDPEreduced the MFI values, the tensile strength and modulus, whereas the elongation at break increased.Interfacial interaction was better for LDPE/biopolymer blends containing soybean oil. Blendsprepared with oil showed the same behaviour as LDPE/biopolymer blends, indicating thatbiopolymer was the main factor that influenced the properties of blend.

Abstract: This paper presents corrosion failure analysis of 13Cr stainless steel (SS) in gas pipeline ingas pipeline, which was used as thermocouple protecting material (TPM). A portion of TMP faileddue to pitting corrosion under unknown circumstances. Scanning electron microscopy (SEM) andX-ray diffraction (XRD) are employed to characterize the scales and/or corrosion products near thefailed portion. Based on visual and microscopic analyses, reviewing the background information andthe thermodynamic calculation, the following rapid pitting corrosion failure sequences wereidentified: Once the pitting appeared, in addition to the gas leakage and expansion, the temperaturedrop should lead a small amount of water in dry gas to condense on the surface of TPM. On one hand,the high salinity produced water will corrode the thermocouple. On the other hand, the high salinityproduced water will pass into the annular space of TPM through the pitting because of the pressuredrop, and the water will stay on inner surface for more time than that of external surface, whichaccelerated pitting of TPM. More and more pitting appeared, and the surface roughness increased.The film-forming property of condensation water will also increase. So, the TPM will be scrappedsoon.

Abstract: A large number of blockage appeared in gas wells and pipeline appeared, which causedplugging, corrosion and the increasing of wellbore pressure difference, and seriously affect thenormal production of gas well of problems. In this paper, the water quality of produced water fromthe severe cases of single wells or pipeline water were analyzed, also include the composition ofblockage and core with the chemical volumetric method (CVM) , X-Ray Diffraction (XRD) and x-rayfluorescence (XFS) method. Meanwhile, the core powder was leached in simulated acid worksolution, and then the leaching solution was analyzed with CVM. The experimental results show thatThe produced water has high salinity, high contents of Ca2+, Ba2+ and Sr2+, low pH value, which leadto corrosion and scaling. The main components of the blockage are acid insoluble strontium sulfate(barium) scale or corrosion product or mixture of corrosion and CaCO3 scaling product. Ca2+, Ba2+and Sr2+ were easy to scale in wellbore or pipeline when they encountered other produced water fromdifferent formation. The Ca2+, Mg2+, Ba2+, Sr2+ and Fe 2+/3+ mainly derived from the dissolution offormation debris in formation water and working fluid (especially acidic working fluid) to reservoirrock, so the salinity of the produced water increased, and the trend of scaling and corrosion alsoincreased with the gas field development.

Abstract: Phenolic resin can be formed from the powder of cashew nut shell waste (CNSW), phenoland sulfuric acid. In this study, the powder of CNSW, phenol and sulfuric acid were mixed withvarious ratios in the reactions for formation of phenolic resin at 150oC during 180 minutes. Theformation of phenolic resin was evaluated by the non-reactive residue of CNSW, which was used tofind the best composition. The molecular mass and the separation of the constituents in the sampleswere also identified by gel permeation chromatography (GPC). The samples with optimizedcomposition were characterized molecular structures and functional groups using Fourier transforminfrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR).

Abstract: The environmental burden due to the production and use of Ordinary Portland Cement(OPC) has become significant in terms of resource use and atmospheric emissions. Alkali-activatedbinders have gained significant attention in recent years as a possible alternative to OPC. Concreteundergoes physical and chemical changes through its lifetime. These changes affect propertiesresulting in either increase or decrease of performance and serviceability. Concrete contracts due tothese changes leading to shrinkage. Shrinkage induces tensile stresses within the members, whichleads to a tendency of cracking, resulting in compromised durability. Shrinkage behavior analysis ofAlkali-Activated Concrete (AAC), without any external loading, is crucial to assess as there is limiteddata available. To further test for shrinkage under restraint conditions, mix development of AAC isnecessary. Mechanical properties and drying shrinkage potential of AAC are evaluated and comparedwith OPC concrete. Basic properties assessed to understand the performance of AAC are compressivestrength, splitting tensile strength and free drying shrinkage. Drying shrinkage test is performed as perASTM C157 for 90 days. Furthermore, the effect of different curing regimes (dry curing, three daysmoist curing, and seven days moist curing) on the mechanical properties and shrinkage is evaluated.The results show that drying shrinkage of AAC exhibit similar behavior to that of OPC concrete whilehaving better early-age strength under moist curing regimes.