bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzyme Immobilization Behavior on the Surface of Hydroxyapatite Capsules under Alkaline Condition
Authors: Yabutsuka Takeshi , Yamamoto Masaya , Takai Shigeomi , Yao Takeshi
Published: November 2018

We prepared hydroxyapatite (HA) capsules encapsulating maghemite particles. In order to evaluate enzyme immobilization behavior of the HA capsules under alkaline condition, we immobilized five kinds of enzymes with different isoelectric point in carbonate/bicarbonate buffer (CBB, pH 10.0). When the enzymes in CBB were moderately charged, immobilization efficiency on the HA capsules showed the highest value. It was suggested that immobilization efficiency was affected according to both pI of enzyme and pH of the surrounding solution and that enzyme immobilized on the HA capsules by not only electrical double layer interactions but also ion interaction and other interactions.
Multifunctional-Dual Drug Delivery Poly-Lactic Acid Biocomposite Coating with Hydroxyapatite for Bone Implants
Authors: Karacan Ipek , Chou Joshua , Ben-Nissan Besim , Macha Innocent J. , Cazalbou Sophie , Milthorpe Bruce
Published: November 2018

The new novel implant designs include the functionality of advanced drug delivery systems in order to improve osteointegration and to inhibit the implant-related post-operative infections. In this research, Ti6Al4V metallic implants were coated with the multifunctional-dual slow drug delivery coating which includes a polymeric matrix system based on a poly-lactic acid thin film and a bioactive ceramic hydroxyapatite. This system consists of two different kinds of pharmaceuticals, which are gentamicin and simvastatin. It is reported in this paper that the simvastatin and gentamicin containing poly-lactic acid coating which was applied uniformly and successfully with and without hydroxyapatite microspheres. Most importantly, the release rate of drugs was controlled with PLA matrix and HAp microspheres which have different dissolution rates in order to prevent the high dosages causing adverse side-effects of drugs.
Sintering Temperature Effect on Hardness of Self-Synthetisized Porcelain Made from Natural Sumatran Sand without Kaolin
Authors: Kurnia Sianny Surya Putri , Taufik Dede , Takarini Veni , Hasratiningsih Zulia
Published: November 2018

Dental porcelain is one of the indirect restoration material with excellent aesthetic properties,on the other hand porcelain hardness frequently causing excessive wear of antagonist teeth. This study aiming to evaluate the effect of sintering temperature on the self-synthesized porcelain hardness. In this experiment, 25 porcelain samples were synthesized using Sumatran sand from Pangaribuan and Belitung regions, with the composition of 65 wt% Pangaribuan feldspar, 25 wt% Belitung silica and 10 wt% potassium salt. The samples were sintered in five different temperatures, which were 1110°C (A), 1120°C (B), 1130°C (C), 1140°C (D), and 1150°C (E). These samples were then invested on 5cm diameter resin each. The hardness was tested using Zwick Roell ZHμ Micro Vickers with 900 gram load for 15 seconds in 5 different indented areas for each sample. The result shows average hardness of 435.8 VHN (A), 461.0 VHN (B), 472.0 VHN (C), 487.6 VHN (D), and 528.7 VHN (E), which were increasing as the sintering temperature increased. Statistic result shows that sintering temperature significantly affected the hardness value of the porcelain (p value < 0.05). In conclusion sintering temperature affects the hardness of self-synthesized porcelain made from Sumatran natural sand without kaolin, although the average hardness of self-synthesized porcelain is still higher than average hardness of teeth enamel.
Loading of Fluvastatin onto Gelatin-Coated Titanium Implants
Authors: Takemoto Shinji , Sasaki Kaori , Sugawara Shiho , Saitoh Setsuo , Sawada Tomofumi , Taira Masayuki , Tanabe Koji , Yoshinari Masao , Hattori Masayuki , Jansen John J. , Leeuwenburgh Sander G.G.
Published: November 2018

We aimed to investigate the effects of alumina blasting and alkaline treatment on the immobilization of gelatin-fluvastatin complexes on titanium disks. Blasted titanium disks were submicron-sized porous while the alkaline treated disks were submicron-and nanoporous. XPS analysis revealed homogeneous coverage of titanium disks with a gelatin layer on top of an intermediate polydopamine treatment. The highest amount of fluvastatin immobilization was observed on top of alkaline treated titanium as compared to the blasted disk. A combination of alkaline pre-treatment followed by polydopamine-assisted immobilization of gelatin facilitated optimal loading of fluvastatin onto titanium dental implants.
Surface Characterization of Dental Porcelain Made from Sumatera Natural Sand
Authors: Takarini Veni , Kurnia Sianny Surya Putri , Taufik Dede , Cahyanto Arief , Hasratiningsih Zulia
Published: November 2018

This research reported hardness and porosity morphology results on five different sintering temperatures as surface characterization of dental porcelain made from Sumateran natural sand mixture composition to prevent excessive wear. Porosity morphology was characterized with JEOL Scanning Electron Microscope (SEM), while the average hardness of each 5 different indented areas was performed with 1000 gr load for 15 seconds using Zwick Roell Vickers Hardness Tester. The result of this study shows that the higher sintering temperature correlates to higher hardness number. SEM analysis indicate less porosity appear in the samples sintered in higher temperature. By modifying the mixture, this study has significantly lowered the hardness number results compared to our previous research samples yielded 936,06 VHN. It can be concluded that positive correlation between higher temperature and hardness emerged from the surface characterization results of the dental porcelain made from Sumatera natural sand. In contrasts the porosity appear to be less developed in higher temperature. However, cracks and pores followed the indentation as in common ceramic products. Further improvement is needed with finding the optimum temperature of desired hardness number and predictable porosity, which resemble tooth enamel.
Effectiveness of Two Type Coupling Agent of Dental Composite Nanofiller Prototype with Addition of Acetone in Preparation
Authors: Karlina Elin , Djustiana Nina , Febrida Renny , Faza Yanwar , Seniyah Seniyah , Panatarani Camellia , Joni I Made
Published: November 2018

Nano size of ceramic filler (nanofiller) are tend to possess difficulties to be covered by resin matrix due to large surface area to volume ratio. Addition of aceton known as the diluent agent by introducing more content of filler as well as helping distribution of the filler in the resin matrix in application of dental composite restoration. In this study, a total 24 specimens of dental composite prototype; nanofiller-TMPS and nanofiller-MPTS were prepared using a customized acrylic mold and they were divided into two groups based on filler/resin ratio (n=6 each group). In the process of dental composite making, acetone were added into resin; 1 ml (filler/resin, 50/50) and 5 ml (filler/resin, 80/20) untill specific consistency obtained. The specimens were stored in distilled water for 24 hours at 37°C then subjected to hardness test using Vickers hardness tester machine, LECO – Japan M– 400–H1 with the load of 200 grams for 15 seconds (ADA Specification No. 27). Data were statistically analyzed using t independent test (α=0.05). The result revealed that dental composite prototype contain nanofiller-MPTS with filler/resin rasio (50/50) were statistically significant higher than dental composite prototype contain nanofiller-TMPS with same ratio (p<0.05). Otherwise, dental composite prototype with filler/resin ratio (80/20) were no observed statistically significant differences for both nanofiller-TMPS and nanofiller-MPTS (p>0.05). As conclusion, nanofiller modified MPTS are more effective to elevate surface hardness of dental composite prototype than nanofiller-TMPS for 50/50 filler/resin ratio
Controlled Drug Release Property of Nano-Porous Silica Micro Particles and their Cytocompatibility
Authors: Era Yuko , Seitoku Eri , Nakanishi Ko , Bando Yosuke , Nakamura Koichi , Abe Shigeaki , Kusaka Teruo , Nakamura Mariko , Inoue Satoshi , Sano Hidehiko , Yoshida Yasuhiro
Published: November 2018

In this study, we investigated in cytocompativility and controlled release behavior of a model drug from nanoporous silica microparticles (NPSM). When Mouse osteoblastic cells (MC3T3-E1) were exposed to NPMSs, they indicated excellent cell viability. From NPSM contained in dental glass ionomer cement (NPMS-GIC), they can release cationic model drug molecules gradually in water for 2 weeks when they were contained in GIC. In contrast, GIC without NPSM specimens released the molecule only a couple of days. In the case of inionic molecules, their release were alos determined only a couple of days. These results suggest that NPSM can be used as a sustainable drug-release system in dental and medical fields
Understanding Silicon Nitride’s Biological Properties: From Inert to Bioactive Ceramic
Authors: Marin Elia , Rondinella Alfredo , Boschetto Francesco , Zanocco Matteo , McEntire Bryan , Bal B. Sonny , Pezzotti Giuseppe
Published: November 2018

Due to the favourable combination of mechanical strength and fracture toughness, silicon nitride has been applied as a load-bearing bioceramic, in particular for implants used in spinal fusion surgery. Only recently it has been observed that the supposedly inert surface of silicon nitride is actually bioactive: a slow, but not negligible, pH controlled, ionic exchange between nitrogen and oxygen leads to the formation and elution of silicic acid and ammonia groups, also resulting in an effective protection against bacteria colonization. These properties could be further modulated by chemical and mechanical treatments.
Inhibitory Effects of Zoledronic Acid-Loaded Bioresorbable Carrier on Osteosarcoma
Authors: Honda Michiyo , Suzuki Norihiro , Nagata Kohei , Aizawa Mamoru
Published: November 2018

Calcium phosphate cements have attracted much attention as a drug carrier for local administration of bisphosphonates which are widely used to treat bone diseases such as osteoporosis and bone tumors. In the present study, to design the novel drug delivery carrier for bone metastasis without undesirable side effects, zoledronic acid (ZOL) loaded-bioresorbable β-tricalcium phosphate (β-TCP) cement was fabricated on the basis of chelate-setting mechanism of inositol phosphate (IP6) using ZOL loaded-β-TCP powders. In order to examine the minimally effective concentration of ZOL on osteosarcoma with no effect on osteoblast viability, cells were treated with ZOL. At a concentration over 10 μM, ZOL significantly inhibited the proliferation of osteosarcoma, whereas osteoblasts proliferated normally. On the other hand, the ZOL showed concentration-dependent adsorption to IP6/β-TCP powders through chemisorption. Based on these results, we have fabricated ZOL loaded-IP6/β-TCP cements and evaluated the anti-tumor effect on osteosarcoma. We found that ZOL loaded-IP6/β-TCP cements have an inhibitory effect on osteosarcoma and induced apoptotic like-cell death. These results suggest that ZOL loaded-IP6/β-TCP cements are promising materials to develop the local treatment for bone metastasis.
Preparation of Calcium Phosphate Glasses Containing Nb2O5 and TiO2
Authors: Sato Patrícia Suemi , Maeda Hirotaka , Obata Akiko , Kasuga Toshihiro
Published: November 2018

60CaO-30P2O5-(10 ̶ x)Nb2O5-xTiO2 (x = 0 ~ 10, mol%) glasses were prepared in order to obtain biomaterials with high chemical durability and therapeutic ions releasability. Dissolution test of these glasses using Tris buffer solution showed the controlled release of niobate ions from Nb2O5-containing glasses and the formation of calcium titanate in some of them. These behavior might induce positive effects for bone regeneration.
Cotton-Wool-Like Resorbable Bone Void Fillers Containing β-TCP and Calcium Carbonate Particles
Authors: Osada Naoki , Makita Masashi , Nishikawa Yasutoshi , Kasuga Toshihiro
Published: November 2018

Cotton-wool-like bioresorbable bone void fillers consisting of β-tricalcium phosphate (β-TCP), siloxane-containing vaterite (SiV) and poly (L-lactic acid) (PLLA) was prepared by an electrospinning method. The fibers, which were 50 ~ 150 μm-width with 10 ~ 30 μm-thickness, were entwined. The resulting cotton-wool-like material showed mechanical flexibility and excellent shapability; it showed easy, excellent mechanical-fixation in defects. The in vivo performance of this material was examined in the distal femur in New Zealand white rabbits. It was evaluated using micro CT and histologic analyses at time points of 6 and 12 weeks. These analyses of the defect sites verified normal healing response and new bone formation. The in vivo testing with rabbits showed good biocompatibility and excellent osteogenic ability.
Synthesis of Spherical Phosphorus-Containing Mesoporous Silica for Improving their Reaction Behavior in Simulated Body Fluid
Authors: Shang Yu Cheng , Yamada Shota , Chai Ya Dong , Tagaya Motohiro
Published: November 2018

Spherical phosphorus–containing mesoporous silica (PMPS) particles were synthesized. In the PMPS particle preparation using the cationic surfactant (cetyltrimethylammonium bromide) as the template, the amphiphilic surfactant (Pluronic P123) and diethyl(2–bromoethyl)phosphonate were used for the particle shape control and the phosphorus source, respectively. Furthermore, we investigated the chemical reactions of the PMPS particles in simulated body fluid (SBF). By the phosphorus–containing, the hydroxyapatite formation and silicate ion dissolution ability on the PMPS particle surfaces were enhanced. These characteristic features will be useful for the biomedical applications such as bone formation.
Apatite-Forming Ability of Hydrophobicized Cellulose Nanofiber Imparted by Combination with Apatite Nuclei
Authors: Yoshioka Takuya , Yabutsuka Takeshi , Takai Shigeomi , Yao Takeshi
Published: November 2018

The fabrication of bioactive hydrophobicized cellulose nanofiber consisted of two steps. First, cellulose nanofiber-apatite nuclei composites were prepared by mixing apatite nuclei with cellulose nanofiber slurry and air-drying. Second, the obtained specimens were immersed in alkylketene dimer. By this final treatment, the surface of cellulose nanofiber-apatite nuclei composites could be hydrophobicized. In order to impart apatite-forming ability to the hydrophobicized cellulose nanofiber, the various amount of apatite nuclei were mixed with cellulose nanofiber slurry, and the bioactivity was evaluated by using simulated body fluid.
Bioactivity Assessment of Apatite Nuclei-PVDF Composite Thin Films
Authors: Zamin Hasnat , Yabutsuka Takeshi , Takai Shigeomi
Published: November 2018

Particles of calcium phosphate were precipitated by raising the temperature and the pH of simulated body fluid (SBF) named Apatite Nuclei (AN). AN and polyvinylidene fluoride (PVDF) composites thin films with different weight percentages of AN in PVDF were fabricated by solution casting technique, using doctor blade method. In order to assess the bioactivity, the thin films were soaked in simulated body fluid (SBF). It was found that the film containing 30 wt.% of AN in PVDF actively induced hydroxyapatite formation in 3 days soaking period in SBF.
Fabrication of Novel Hemostatic Film with Oxidized Cellulose and Sugar-Containing Hydroxyapatite
Authors: Noh Yeon Jeong , Umeda Tomohiro , Musha Yoshiro , Itatani Kiyoshi
Published: November 2018

The novel hemostatic film for the surgery of bone diseases was fabricated using TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl)-oxidized cellulose nanofibers (TOCNs), and phosphoryl oligosaccharides of calcium (POs-Ca) or sugar-containing hydroxyapatite (s-Ca10(PO4)6(OH)2; s-HAp). Three kinds of the hydrophilic and transparent films with the thicknesses of 10 to 20 μm were fabricated, i.e., TOCN, POs-Ca-added TOCN and s-HAp-added TOCN films. Among these films, the uptake amount of the simulated body fluid by s-HAp-added TOCN film was as high as 5,543%, which was expected to quickly stop bleeding of larger amount of blood for the hemostasis.
Fabrication of Bioactive Polycaprolactone by Incorporation of Apatite Nuclei
Authors: Zamin Hasnat , Hiruta Tomoko , Yabutsuka Takeshi , Takai Shigeomi
Published: November 2018

When the pH or the temperature of a simulated body fluid is raised, fine particles of calcium phosphate are precipitated, which are named apatite nuclei (AN). In this study, we aimed to impart bioactivity to polycaprolactone by incorporating AN. AN-PCL composite films having different weight percentages of AN in PCL were fabricated by solution casting technique, using doctor blade method. Results showed that more than 20 wt.% AN-PCL films were fully covered with hydroxyapatite layer in three days soaking period in SBF.
Fabrication of Hydroxyapatite/Cellulose Fiber Composite with Sheet-Like Structure
Authors: Watanabe Shota , Nagata Fukue , Miyajima Tatsuya , Sakurai Makoto , Suzuki Aoi , Kato Katsuya
Published: November 2018

Natural bone is a complex material with well-designed architecture. To achieve successful bone integration and regeneration, the constituent and structure of bone-repairing scaffolds need to be flexible and biocompatible. HAp, as the main composition of bone minerals, has excellent biocompatibility, while CMC comprised of a three-dimensional network were high flexibility. Therefore, CMC/HAp composite have been attracted attention due to the development of bone tissue engineering. In this work, carboxymethyl cellulose (CMC)/hydroxyapatite (Ca10(PO4)6(OH)2; HAp) composite have been developed as three-dimensional scaffold for bone tissue engineering. Scanning electron microscopy revealed that the CMC/HAp composite have sheet-like structure. The amount of precipitated HAp of CMC/HAp composite was investigated using Thermogravimetric analysis. The amount of precipitated HAp in products prepared with 100 mg CMC was 49.8 wt%, while the amount of precipitated HAp in products prepared with 1000 mg CMC was 22.3 wt%. These results revealed that the amount of precipitated HAp in CMC/HAp composite was affected by CMC amount as prepared.
Influence of Multi-Phase Carboxylate Salt on Mortar Properties under Sulfate Environment
Authors: Shi Liang , Liu Jia Ping , Cai Jing Shun , Gao Yun , Liu Jian Zhong
Published: November 2018

A novel multi-phase carboxylate (MPC) salt was prepared by free radical polymerization. Influence of MPC salt on properties of mortar under sulfate environment was investigated. The results from static solution soaking and wet-dry cycling tests indicated that MPC would not bring negative effects on strength and shrinkage of mortar. In particular, MPC was able to reduce the strength loss as a result of inhibiting the generation and growth of ettringite in static solution soaking test. The crystal expansion of AFt was reduced since the Ca2+ dissolution and SO42- ingress were less. Meanwhile, the strength loss of mortar under sulfate wet-dry cycling could be reduced as well by MPC. MPC inhibited the growth of CaSO4·2H2O crystals by replacing the functional groups. The growth of micro-cracks in cement paste was inhibted and the the risk of crystal expansion and destruction of mortar was reduced. It was believed that MPC exhibited an excellent sulfate attack resistance for mortar.
Preparation and Thermoelectric Properties of Bi Doped Ca3Co4O9 Based Thermoelectric Materials
Authors: Wang Jing , Chen Qin , Zhu Xia Chun , Lee Seok Je , Park Kyoung Woo , Jhun Chulg Yu
Published: November 2018

Polycrystalline Ca3-xBixCo4O9 samples have been prepared by solid-phase reaction followed by spark plasma sintering process. The thermoelectric properties have been systematically investigated from room temperature to near 1000K. It is found that the change of the carrier concentration leads to the change of resistivity, which is mainly associated with doping induced point defect phonon scattering. The change of the thermal potential mainly comes from the spin entropy. In addition, polycrystalline Ca3-xBixCo4O9 had a maximum figure of merit of 0.30 at 973 K, which was about 50% higher than Ca3Co4O9. It indicated that doping approach can effectively improve the thermoelectric performance of Ca3Co4O9+δ-based material.
SO2 Removal by Powder Activated Carbon in a Drop Tube Furnace Experimental System
Authors: Li Bing , Ma Chun Yuan
Published: November 2018

SO2 adsorption by powder activated carbon was investigated in a low temperature drop tube furnace. The effects of C/S mole ratio, adsorption temperature, SO2, O2 and H2O concentration on SO2 adsorption kinetics were studied. The results show that SO2 is quickly adsorbed on powder activated carbon in the initial stage and then SO2 adsorption capacity slow increases with time. The Bangham kinetic model can be used to predict SO2 adsorption in the low temperature drop tube furnace. SO2 removal efficiency increases and SO2 adsorption capacity decreases with C/S mole ratio increasing. SO2 removal efficiency and SO2 adsorption capacity both decrease with adsorption temperature increasing. SO2 removal efficiency decreases and SO2 adsorption capacity increases with SO2 inlet concentration increasing. The O2 and H2O from flue gas promote SO2 adsorption by powder activated carbon.
Study on the Morphology, Mechanical, Thermal Stability Properties of Poly(Lactic-Acid)/Poly(Ether-Block-Amide) Blends Prepared by Triple-Single Screw Extruder
Authors: Xue Bin , He He Zhi , Liu Bi Da , Xue Feng , Zhu Zhi Wen , Liu Shi Ming , Chen Ming , Wang Guo Zhen , Zhan Zhi Ming , Chen Qing Hua , Chen Deng Long
Published: November 2018

In this work, PLA /PEBA blends with the addition of different PEBA contents were prepared via self-made Triple-Single Screw Extruder, the phase morphology, mechanical properties thermal stability of PLA /PEBA blends with PEBA content were investigated. For the pure PLA, the tensile strength decreased, while the elongation at break and the impact strength increased significantly with addition of 15% PEBA. The which were improved nearly 23 and 5 times. The results illustrate that the soft component PEBA was beneficial to improve the tensile ductility and the toughness of PLA. SEM measurements indicate the PEBA and PLA intertwined with each other, two phases interface bond tightly, improving the compatibility of the blends when PEBA content is not more than 15 wt%, with further increasing PEBA, the two-phase interface appears and decreases the interfacial adhesion, resulting in the poor mechanical properties of blends.TG results reveal that thermal stability of PLA/PEBA blends was improved.
The Study of Different Area Weight of Fibers as Ablative Polymer-Based Composite for Solid Rocket Motor
Authors: Ngamsantivongsa Phimraphas , Boonthalarath S. , Wong-Ek B. , Nuanklai S. , Kanasittiboon T. , Bunluekadee A.
Published: November 2018

High performance composites are becoming progressively significant in the aerospace industry for severe temperature. Fiber Reinforced Plastics (FRP) is a general term for composite materials or parts that consist of a resin matrix containing reinforcing fiber such as glass or fiber with more strength or stiffness than the resin. FRP is mostly used to denote glass fiber-reinforced plastics. In this study, the test composites were obtained from a phenolic resin (PR) with different area weight of fibers for comparing the ablation resistance using the hot compression molding technique. The ablation performance of the composites was investigated under an oxy-acetylene torch. An oxyacetylene torch, providing temperatures above 2300 °C, was chosen as the heating source. Moreover, the physical properties of the composites were determined by using standard experimental methods. These experimental results indicated that the fabricated composites with greater area weight of fibers exhibited outstanding mechanical properties and excellent ablation resistance. The overall experimental characteristics of the PR/EWR600 composites meet most of the necessary high temperature application criteria.
Physical Characterization of Hafnium Oxide Thin Films Annealed in Vacuum
Authors: Václavek Lukáš , Tomaštík Jan , Nožka Libor , Čtvrtlík Radim
Published: November 2018

Hafnium oxide (HfO2) is a material characterized by a good mechanical, thermal and chemical stability and is used as a material in a variety of technological applications in optics and electronics. In this work the influence of annealing temperature on the mechanical structural properties of amorphous HfO2 thin film was explored. Films were deposited by electron beam evaporation and annealed in the temperature range from 200 °C to 500 °C in vacuum. Mechanical properties such as hardness and elastic modulus were determined using nanoindentation, while cohesive-adhesive properties of the film using a scratch test. Surface morphology was determined using a confocal microscope and structure using XRD. The transformation of amorphous phase of the films to the nanocrystalline monoclinic phase was observed after vacuum annealing at 500 °C. This crystallization leads to increase in hardness on one hand but also to growth of brittleness and in turn to decrease in scratch resistance on the other hand.
Effect of Crystallographic Orientation on Nanoindentation Response of Fe3Si Single-Crystals
Authors: Čech Jaroslav , Haušild Petr , Materna Aleš
Published: November 2018

Deformation mechanisms and mechanical properties of Fe3(wt.%)Si single crystal in two different orientations were investigated by spherical indentation. For correct interpretation of measured data and better understanding of the deformation mechanisms under the contact area, finite element simulations were carried out and resolved shear stress in available slip systems was computed. Pop-in behavior, differences in hardness, indentation modulus and shapes of residual imprints were observed and associated with different activation of slip.
Comparison of the Fatigue Crack Propagation Rates in S355 J0 and S355 J2 Steel Grades
Authors: Seitl Stanislav , Miarka Petr , Klusák Jan , Fintová Stanislava , Kunz Ludvík
Published: November 2018

The use of S355 high strength steel in civil engineering to design bridges, its elements or simple engineering parts allows material and economical savings meeting the strict construction requirements. The knowledge of the fatigue resistance of material plays the key role during design and maintenance of the bridge structures. This contribution brings a comparison of the fatigue crack growth resistance of two standard S355 J0 and S355 J2 steel grades. Differences in chemical composition and the texture of material structure could generally play a role in the fatigue crack growth. This study shows that in the case of studied steels the chemical composition has an influence on material fatigue behaviour, whereas the texture of material structure is irrelevant.
Selecting a Technology to Increase well Capacity and Enhance Oil Recovery of the YUS11 Formation of the Fainsk Oil Field
Authors: Aleksandrov Vadim , Kadyrov Marsel , Markov Alexander , Golozubenko Vadim , Aleksandrov Sergey
Published: November 2018

To increase the development efficiency of reservoirs, methods to intensify inflows and enhance oil recovery are applied. The geological and field experience of applying these methods shows that a high technological effect can be reached in specific geological and geophysical conditions while in other conditions efficiency will be insignificant. In this relation, an important solution for this problem is the justification of selecting the most efficient technologies of stimulating pay zones. The research objective is to select the most optimal technologies of stimulating pay zones to increase the development scope and enhance oil recovery. Using geological and field analysis, a complex quantitative assessment was done for the efficiency of using methods to enhance oil recovery and stimulate pay zones in both production and injection wells.
Substantiation of the BFZP Technology Application at the Object YUS11 of the Fainsk Oil Field
Authors: Nesterov Ivan , Kadyrov Marsel , Ponomarev Andrey , Drugov Denis , Zavatskij Mikhail
Published: November 2018

Bottomhole formation zone processing (BFZP) is performed at all phases of oil field development to restore and improve the filtration-capacity properties of the bottomhole formation zone to improve the oil yield. The choice of the BFZP technology is made basing on the study of the reasons for low well yield with account for the collector properties of productive sediments and rheological characteristics of the formation fluids, as well as a special geologic-geophysical and development-hydrodynamic study for the assessment of the porosity and permeability properties of BFZ. The research objective is to develop the criteria and assess the conditions for the application of bottomhole formation zone processing technologies for the upper Jurassic formations. Analysis of the results of laboratory and industrial research allowed offering the most efficient technologies for the influence on the upper Jurassic deposits.
Effect of Electroslag Refining on Cleanness, Microstructure and Mechanical Properties of a Newly Developed CrNiMoWMnV Ultrahigh-Strength Steel
Authors: Ali Mohammed , Porter David A. , Kömi Jukka I. , Eissa Mamdouh , Faramawy Hoda El , El-Shahat M.F. , Mattar Taha
Published: November 2018

The cleanness, microstructure and mechanical properties of a newly developed CrNiMoWMnV ultrahigh-strength steel with and without electroslag refining (ESR) with 70% CaF2, 15% Al2O3 and 15% CaO have been studied. This steel was designed and melted in an air induction furnace followed by refining using ESR. Cast ingots with and without ESR were forged at temperatures in the range 1100 - 950 °C. Laser scanning confocal microscopy, field emission scanning electron microscopy electron back scattering diffraction, electron probe microanalysis and X-ray diffraction have been used to investigate the microstructure and non-metallic inclusions (NMIs) of forged ingots produced with and without ESR. Hardness, tensile and Charpy-V impact tests were performed. ESR reduced the total impurity level i.e. O%+ N%+ S% by 26 % and the area fractions and numbers of NMIs by 17% and 7% respectively. The NMIs are classified into four major classes: oxides, sulphides, nitrides and complex multiphase inclusions. The microstructure of the forged and air-cooled bars consisted of martensite with a small fraction of distributed retained austenite, a very small fraction of bainite and finely distributed precipitates. The reduction of impurity levels combined with the microstructural changes brought about by the changes in the chemical composition meant that ESR resulted in a significant improvement in some mechanical properties and a marginal improvement in others.
Comparative Study of Spot Welding and Firiction Stir Spot Welding of Al 2024-T3
Authors: Fahmy Mahmoud Hussin , Abdel-Aleem Hamed A. , El-Kousy M.R. , Abdel-Elraheem N. M.
Published: November 2018

This investigation is performed to compare the resistance spot welding (RSW) of aluminum alloy (2024-T3) with friction stir spot welding (FSSW) techniques. In this work, parameters of both resistance spot welding (RSW) and friction stir spot welding (FSSW) techniques were optimized and the optimum welding variables for both techniques were obtained. For FSSW, the tensile shear strength increased with increasing probe length, tool rotational speed and tool holding time. Tensile shear force value of RSW is about 66% of that of FSSW. This is explained by the coarse dendritic structure in resistance spot welding compared to the plastically deformed stir zone and heat affected zone in FSSW. The ratio of nugget shear strength of RSW and FSSW to base metal is about 71% and 149% respectively. The maximum hardness was obtained in stir zone at the surface of the tool. Very fine grain size of about 4 microns was obtained in stir zone followed by elongated and rotated grains in TMAZ where dynamic recrystallization did not occur.
Effect of Thermal Cycle on Microstructure and Corrosion Behavior of Duplex Stainless Steel SAF 2205 Electron Beam Welded Joint
Authors: Khafagy Sameh M. , Morsy Morsy Amin , El Sherbini H.M. , Barakat Y.F.
Published: November 2018

It is known that heat treatment (HT) highly affects the properties of base metal (BM) and fusion zones (FZ) of duplex stainless steel (DSS). In fact, it may give unwanted structure changes. Duplex stainless steels SAF 2205 welded joint was subjected to thermal cycle at temperature of 850◦C at holding times 1, 3, 5 and 7 hours. The influence of heating cycles and concentration of corrosive medium on the corrosion properties and microstructure of 2205 alloy was the objective of this work. It was found that process led to noticeable decrease in the corrosion resistance of BM and FZ specimens; moreover the decrease was large in BM than FZ. It was also found that sigma phase (σ) precipitated in the different zones of the structure. σ phase volume fraction was found to increase with increasing the holding time of HT, and its increase is larger in BM. Corrosion resistance was found to be oppositely related to σ phase formation. Secondary austenite phase (γ2) was also precipitated and its volume fraction in FZ was found to increase with increasing the holding time of HT and decreased in BM.
Surface Treatment of AISI M2 Tool Steel by Laser Melting
Authors: Newishy Mohamed , Abdel-Aleem Hamed A. , El-Kousy M.R. , El-Mahallawi Iman , El-Batahgy A.
Published: November 2018

Attempt was made to improve the surface hardness and wear properties of AISI M2 high speed tool steel. Laser surface melting (LSM) of tool steel was conducted with 2.2 KW Nd:YAG laser as heating source. Conventional hardening of the tool steel was applied. Characterizing the LSM, with optical and field emission scanning electron microscopy and surface hardness technique was used to evaluate the micro-hardness and mechanical behaviour of different regions of melting pool. AISI M2 tool steel is approximately HV 260, hardness after conventional treatment was 850 HV and the hardness after laser surface heat treatment is around 900 HV. It was found that there is a considerable influence of the laser power density and scanning velocity on the melted zone dimensions and the re-solidified structure. Increasing laser energy and reducing the laser scanning rate results in deeper and wider melt pool formation.
Preparation and Characterization of an Emulsion Paint Based on Arghel Extract as an Eco-Friendly Corrosion Inhibitor
Authors: Mahgoub F.M. , Hefnawy Ahmed , El-Shnawie Mohamed , Esmaiel Ahmed
Published: November 2018

Corrosion control of metals is of technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options of protecting metals and alloys against corrosion globally. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors which do not contain heavy metals or other toxic compounds. In addition to being environmentally friendly, plant products are inexpensive, readily available and renewable. With the growth of the green movement, it is important to prepare environmentally friendly anticorrosive paints to save lot of money, which are lost each year because of corrosion. This study utilized optical measurements, electrochemical impedance spectroscopy (EIS) analysis, scanning electron microscope (SEM) analysis, immersion test in artificial sea water and morphology observations of Arghel extract (AE) as Eco-friendly corrosion inhibitor incorporated in (styrene-acrylic) emulsion paint. In addition Physical, Chemical and Mechanical Properties of dry paint films of the paint test has been done in absence and presence of the corrosion inhibitor. We found that (styrene-acrylic) emulsion paint with 75ppm AE (SP2) has the best performance in protecting mild steel from corrosion.
Use of Gamma Ray Back Scattering Method for Corrosion Assessment in Insulated Pipes
Authors: ElHoushy Ahmed Abd Elfatah , Hassan Mohamed H. , Soliman Abdelfattah Y. , Abou Mandour Mohsen A.
Published: November 2018

Corrosion of insulated pipes is a major problem in nuclear,petrochemical and other industries.This type of corrosion is difficult to measure by the available techniques of ultrasound and transmission gamma or x-ray radiography due to the presence of insulating material and limited accessibility to both sides. Gamma-ray backscattering technique is a non-contactmethod and is highly suitable for buried insulated pipes where access is limited to one side only.In the present work, MCNP5 code was used to simulate a case where pipe corrosion (i.e., wall thinning) was measured by gamma backscattered technique. A steel pipe is bombarded by collimated gamma ray beam of 1 cm diameter from an 8 mCi137Cs source. The pipehad different wall thicknesses and was wrapped with a commercially available insulator. Upon interaction with the pipe wall, a 2x2 cm NaI (Tl) scintillation detector was used to measure the scattered radiation due to Compton scattering. The codewas used to evaluate the sensitivity of the device to predict pipe wall thinning as an indication for pipe corrosion. Then, parametric analysis was done to investigate the effects of pipe diameter, insulator thickness, source collimator diameter, source shield thickness as well as the thickness of the shied between the source and the detector on the device response. Effect of empty vs. water-filled pipes on the device response was also investigated. Results indicate that Gamma-ray backscattering technique can be used successfully as a non-destructive test for measuring wall thinning of insulated pipes as an indication of their corrosion.
Evaluation of the Inhibition Efficiency of a Green Inhibitor on Corrosion of Cu-Ni Alloys in the Marine Application
Authors: Gaber Ghalia A. , Maamoun Maamoun A. , Ghanem Wafaa A.
Published: November 2018

The aim of this article describes the application of green tea aqueous extract as an eco-friendly corrosion inhibitor for two Cu-Ni alloys in 3.5% NaCl solution. This ability has been studied by using electrochemical techniques (i.e. PDP, CT and EIS), IR spectroscopy measurements and the surface analysis technique (i.e. SEM/EDX). This ability was compared with it's of a commercial cooling water (green water). The results show that tested extract exhibited a good ability to decrease the corrosion rate of alloys in 3.5% NaCl solution.The inhibition efficiency of the green water and green tea extract inhibitors increased with increasing the concentration and decreased with increasing the temperature. The inhibition efficiency of two Cu-Ni alloys which reaching ̴ 91.5% and ̴ 93.9% with 50 % green tea aqueous extract for Cu-10 Ni and Cu-30 Ni alloy, respectively. Electrochemical impedance showed that the change in charge transfer resistance (Rct) and double layer capacity (Cdl) which adsorbed on the alloy surface. Adsorption of the inhibitors gives a good fit to Langmuir isotherm model. Some thermodynamic parameters of activation and adsorption processes were also determined and discussed. Surface examination studies by SEM and EDX confirm the presence of protective film on the alloy surface. In the present study, we investigated the corrosion of the Cu-Ni (cupronickel) alloys in 3.5 % NaCl environment to simulate the seawater desalination plants conditions. Therefore, the future studies can be focused on the development of polymeric compounds used as self- healing or production of new natural corrosion inhibitors especially recommended the waste product of green tea.
Micro-Machining of Nano-Polymer Composites Reinforced with Graphene and Nano-Clay Fillers
Authors: Shyha Islam , Fu Guo Yu , Huo De Hong , Le Bao , Inam Fawad , Saharudin Mohd Shahneel , Wei Jia Cheng
Published: November 2018

Following a comprehensive review of nanocomposite materials and their machinability, this paper details experimental results from the micro-slotting of two different nanocomposites reinforced with graphene platelets and nanoclay fillers as opposed to their base material matrix. The evaluation includes the quality of machined surfaces characterised by SEM, cutting forces monitored using force dynamometry, and surface roughness measured using both contact and non-contact techniques. The evaluation included four filler percentages by weight between 0.1 and 1% in addition to 0% with the plain matrix material. The effect of feed rate is also evaluated at 3 levels (10, 20 and 30 μm/rev) with cutting speed at 4 levels (15.7, 31.4, 62.8 and 94.2 m/min). Dry cutting experiments were performed on an ultra-precision desktop micro-machine tool. Uncoated tungsten carbide end mills 1 mm in dimeter were used in all tests. Surface roughness increased gradually with feed rate while cutting speed had no effect. Ra values ranged from 0.1 – 0.35 μm. Common increases in cutting forces with either feed rate or cutting speed were observed. Forces in general were higher for the material reinforced with 0.3–0.5% nanofiller. Negligible tool wear occurred following the cutting of 140 slots of 100 μm depth (removing 182 mm3 of the material).
Tool Wear and Form Accuracy in Ultrasonic-Assisted Milling of Soda-Lime Glass
Authors: El-Taybany Yasmine Abd El-Mohsen Ahmed , Hossam Mohab , El-Hofy Hassan
Published: November 2018

Machining of hard and brittle materials is inherently involved with tool wear, which influences the dimensional and form accuracy of the machined product. Ultrasonic-assisted machining process is suitable for hard-to-cut materials such as ceramics, glass, and metal matrix composites, etc. In the current study, the mechanism of tool wear is investigated during ultrasonic-assisted milling of soda-lime glass as one of hard and brittle materials. Ultrasonic-Assisted Milling (UAM) combines the material removal mechanism of grinding and the milling kinematics with ultrasonic assistance. The effect of different process parameters, i.e. feed rate, depth of cut, cutting fluid, and ultrasonic vibration assistance on the tool wear behavior are investigated. Form accuracy of the machined slots is also investigated. The results showed that UAM produces less tool wear than conventional milling (CM). However, CM gives less error in the slot dimensions than UAM.
Development of a New Glass for both Visible and Near-Infrared Optical Applications
Authors: Abd El-Ghany Hytham
Published: November 2018

A glass system of composition 40P2O5-40ZnO-(20-x)Na2O-xCdO (where, x = 1, 2, 3, 4, 5 and 6 mol%) was prepared using the conventional melt quenching technique. The glass formability of the prepared samples was inspected using XRD technique. Archimedes’ method was used to determine the density of the prepared glass samples then the molar volume was calculated. The optical spectroscopic investigations of the prepared glass samples were carried out over the spectral range (190-2500 nm). The proposed glass showed a successive transparency in both visible and near-IR ranges of spectrum till 2500 nm with considerably high transmission of about 78%. The refractive index of the glass samples with some other useful parameters such as dielectric constant, electric susceptibility and electronic polarizability of the prepared glass were evaluated. The results suggest the practicality of utilizing such new glass in the fabrication of optical supplies such as lenses and optical windows used for Nd:YAG lasers. The metallization criteria data of the prepared glass propose a good basis for predicting new nonlinear optical materials.
Effect of Friction Stir Processing on the Microstructure and Mechanical Properties of A384 Aluminum Alloy
Authors: Abdel-Aziz Ahmed Ibrahim , Abou Taleb Ahmed S.A. , El-Baradie Z.M. , Farahat Ahmed Ismail Zaky
Published: November 2018

Friction stir processing (FSP) is a solid-state technique for microstructural modification. The aim of this work is to evaluate the effect of input process parameters of friction stir processing (tool rotational speed rpm, travel speed mm/min) on microstructure and mechanical properties of A384 aluminum alloy. A384 aluminum alloy was cast using conventional stir casting process. The obtained alloy was subjected to friction stir process using different input parameters (rpm, mm/min) with double pass. Water was used as cooling medium during process. The microstructures of investigated alloys were characterized by optical, SEM microscopes, EDS and Map analyzer, while mechanical properties were evaluated by using tensile test. The results indicate that; after friction stir processing, the microstructure of as-cast alloy was greatly improved. Needle-like eutectic Si and Chinese Script a-Fe were modified to fine precipitates. Meanwhile, coarse primary Si and large plate b-Fe phase were dissolved. On the other hand, mapping analysis shows homogenous distribution of different alloying elements through the matrix. The higher values of tensile properties were obtained at 1200 rpm and 80 mm/min. UTS and YS were increased by 98% and50%, respectively. Meanwhile, ductility was approximately three times higher than that of cast alloy.
Nano Titania Reinforced Limestone Cement: Physico-Mechanical Investgation
Authors: Abdelzaher Mohmoud A. , Hamouda Asmaa S. , Ismail Ibrahim M. , El-Sheikh M.A.
Published: November 2018

Studying physical and mechanical properties of limestone cement pastes blended by TiO2 nanoparticles (i.e., particle size less than 100 nm). Three mixes are prepared for this study (5.00, 10.00 and 25.00 wt. % of limestone) partially replaced cement/clinker by TiO2 nanoparticles. Fillers are carefully selected which reinforcing cement workability or water retention they could be inert or have slightly hydraulic properties. Limestone is most common filler that fills the pores between cement particles due to the formation of monocarboaluminate, while nanoparticles increase the hydration C-S-H gel product and calcium titanium silicate which hardened the cement pastes. Nanoparticles show a great effect in reinforcing the mechanical strength of cement pastes due to the fact that TiO2-nanoparticles act as active nuclei site forming C-S-H gel observed as honeycomb-like plus improving cement to water demined (W/C) ratio. SEM analysis proves that the morphology of cement structure is well arranged and compacted.
Enhancing the Wetting Properties of Polypropylene and Polyethylene Nonwoven Fabrics Using a Cost-Effective Surface Dielectric Barrier Discharge
Authors: El-Saber M. , Abou-Gabal Hanaa , Aloufy A. , El Saghir A.
Published: November 2018

An atmospheric pressure surface dielectric barrier discharge (SDBD) was used for surface treatment of Polypropylene (PP) and Polyethylene (PE) nonwoven fabrics which are widely used in filtration media, oil adsorbents, biomedical textiles, etc. The SDBD reactor has been built using the Printed Circuit Board (PCB) which is an inexpensive material available in the local market. The use of the PCB led to the ease of fabrication of a low-cost discharge electrode system that can be scaled up without difficulty. The effect of the plasma treatment on the hydrophilic behavior of the treated samples was studied using water contact angle (WCA) measurements. The microstructure of the PP and PE nonwoven fabrics before and after plasma treatment was characterized by Scanning Electron Microscopy (SEM). The results showed that the plasma treatment converted the fiber surface from smooth to textured surface. This resulted in enhancing the wettability of both materials but with more pronounced effect on the PP.