bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption removing various basic nitrogen compounds from model diesel over allochroic silica gel
Authors: Hong Xin , Li Yunhe , Gao Chang , Zhao Yonghua , Tang Ke
Published: September 2018

The adsorption removal of quinoline from model diesel by using alumina, diatomite, silica gel, and allochroic silica gel as adsorbents was investigated. The experiment results indicated that the adsorption denitrogenation performance of allochroic silica gel was more superior to other three adsorbents. The silica gel and allochroic silica gel were confirmed by characterization with X-ray diffraction, nitrogen adsorption–desorption, and ammonia temperature programmed desoption (NH3-TPD). X-ray diffraction results indicated that both the samples were amorphous structures. The average pore diameters of silica gel and allochroic silica gel were 18.46 and 1.80 nm, the Brunauer–Emmett–Teller surface areas were 437.86 and 623.39 m2/g, and the pore volumes were 0.9724 and 0.3442 cm3/g, respectively. The results of TPD showed that the acidity of allochroic silica gel was far stronger than that of silica gel which greatly enhanced its adsorption denitrogenation performance. The adsorption denitrogenation performance of allochroic silica gel for quinoline, aniline, and pyridine from model diesel was as follows: aniline, pyridine, and quinoline. Adsorption temperature, particle size, and arenes added in model diesel had little impact on the removal of aniline and pyridine except quinoline. The adsorbent-to-oil ratio had significant effects on adsorption denitrogenation, especially for quinoline. The N–Co bond between Co in allochroic silica gel and N atom in the basic nitrogen compounds molecule played a significant role. Furthermore, the allochroic silica gel could be easily regenerated by its adsorption denitrogenation performance for quinoline and pyridine by using calcination once or several times, except aniline. The adsorption isotherm results revealed that the adsorption of pyridine and aniline belonged to the Langmuir–Freundlich binding model, but the adsorption of quinoline belonged to Freundlich model.
The Mono-Prep system increases the detection rate of sputum smear microscopy for diagnosing tuberculosis
Authors: Wu Jiannan , Kong Chengcheng , Huo Fengmin , Liang Qian , Ma Yifeng , Shang Yuanyuan , Zhao Liping , Du Jian , Sun Zhaogang
Published: September 2018

Objective

Direct sputum smear microscopy (DSSM) has a low detection rate. This study investigated whether an alternative method called Mono-Prep smear microscopy (MPSM) can enhance the diagnosis of tuberculosis in tuberculosis laboratories that perform direct smear microscopy in China.

Methods

A total of 117 sputum samples were collected from outpatients who attended Beijing Chest Hospital. DSSM, MPSM, solid culture, and Xpert MTB/RIF were performed on the samples.

Results

The positive rates of DSSM, MPSM, solid culture, and Xpert MTB/RIF were 27.4% (32/117), 40.2% (47/117), 35.9% (42/117), and 52.1% (61/117), respectively. MPSM could detect 15 more cases of tuberculosis compared with DSSM (47 vs 32) among 117 sputum samples. This represented a significantly higher positive rate and sensitivity of MPSM compared with DSSM. However, MPSM appeared to have a lower specificity (81.3%) compared with DSSM (90.7%) with the solid culture used as a standard.

Conclusion

Use of MPSM can increase the number of positive sputum samples, but it still needs improvement.
Effect of clarithromycin in von Hippel-Lindau syndrome: a case report
Authors: Ma Xin , Jing Yuanyuan , Liu Yan , Yu Lisheng
Published: September 2018

Von Hippel-Lindau (VHL) syndrome is caused by germline mutations in the VHL gene and is accompanied by the development of both benign and malignant tumors. Clarithromycin (CAM) is a widely used anti-inflammatory drug that has also been proven effective for treating some cancers. In this study, we present a novel case of a 38-year-old female patient with VHL syndrome confirmed by computed tomography, with no relevant family history. The patient was only offered close follow-up observation after diagnosis, but was orally administered CAM twice daily when her disease progressed. After treatment for 3 months, her inner ear tumors had stopped growing and her kidney cysts had shrunk. Her pancreatic tumors treated with CAM showed no significant increase in size, and the lymph node swelling disappeared. CAM treatment was interrupted for 2 years and then stopped for 5 years when improvements were noted; the patient’s condition thereafter gradually improved and finally stabilized with no obvious side effects. We discuss this case in the context of the published literature and consider the possible mechanisms of CAM action in the treatment of VHL syndrome. To our knowledge, this is the first case report of a patient with VHL syndrome treated with CAM.
Review of risk factors, treatment, and prevention of saphenous vein graft disease after coronary artery bypass grafting
Authors: Gao Jing , Liu Yin , Li Yu-Ming
Published: September 2018

Saphenous vein graft disease (SVGD) is a type of vascular disease that may develop after coronary artery bypass grafting (CABG). SVGD seriously affects the short-term and long-term effects of CABG and increases the incidence of major adverse cardiovascular events. It is very important to identify patients at greatest risk and carry out prevention and treatment measures to determine the risk factors for SVGD. Many factors contribute to SVGD when the vein is grafted into an arterial environment, such as surgery-related factors, smoking, diabetes mellitus, hyperlipidemia, and others. In this review, we discuss the risk factors for SVGD, current surgical and pharmacologic therapies with which to manage SVGD, and the prevention of SVGD.
Clinical impact of the Sherlock 3CG® Tip Confirmation System for peripherally inserted central catheters
Authors: Yamagishi Tomomi , Ashida Hirokazu , Igarashi Takao , Matsui Yo , Nozawa Yosuke , Higuchi Takahiro , Ojiri Hiroya
Published: September 2018

Objective

This study was performed to evaluate the technical success rate and catheter tip malposition rate of peripherally inserted central catheter (PICC) placement using the Sherlock 3CG® Tip Confirmation System (TCS).

Methods

In total, 114 patients who underwent PICC insertion via the Sherlock 3CG® TCS from October 2017 to February 2018 were retrospectively evaluated. The primary endpoints were the technical success rate, malposition rate, and mean procedure time. The secondary endpoints were the sex-related difference in the malposition rate, radiologist’s experience level, and side of insertion. Technical success was defined as procedure completion using only the Sherlock 3CG® TCS without a guidewire or fluoroscopy guidance. In accordance with the North American guidelines, an adequate position was defined as the lower third of the superior vena cava and the cavoatrial junction.

Results

The technical success rate was 97% (111/114). The malposition rate was 16% (18/111), and four catheters were repositioned. There were no significant differences in the malposition rate between the sexes, radiologist’s level of experience, or side of insertion.

Conclusions

PICC placement using the Sherlock 3CG® TCS yielded a high technical success rate and low catheter tip malposition rate regardless of the radiologist’s level of experience or side of insertion.
Takotsubo syndrome and dialysis: an uncommon association?
Authors: Manfredini Roberto , Fabbian Fabio , De Giorgi Alfredo , Cappadona Rosaria , Zucchi Beatrice , Storari Alda , Rodriguez Borrego Maria Aurora , Carmona Torres Juan Manuel , Lopez Soto Pablo Jesus
Published: September 2018

This review was performed to investigate the association between treatment with dialysis and Takotsubo syndrome in patients with end-stage renal disease. We systematically explored the PubMed database using the search terms “Takotsubo cardiomyopathy” and/or “stress-induced cardiomyopathy” and/or “Takotsubo syndrome” in combination with “dialysis” and “uremia.” Of 3630 articles found, 8 articles reporting 10 cases were selected for analysis. Most patients were women, and their age ranged from 51 to 84 years. Diabetes mellitus and hypertension were diagnosed in 40% of patients, and glomerular disease was diagnosed in 30%. One only patient was treated with peritoneal dialysis; all others were treated with hemodialysis. The outcome was unfavorable in only one patient. An association between Takotsubo syndrome and dialysis is uncommon, but not negligible, and comorbidities play a major role in determining the clinical outcome.
Food, work and sleep: Visualising the top food and population centres in Beijing
Authors: Zhou Jiangping , Yang Yuling , Zhang Chun
Published: September 2018

In contemporary cities, the catering sector is much more than only food and/or eating. On the one hand, it is an important source of income, employment and waste; on the other hand, it provides many opportunities for eating out and social interaction. For a given city, where does the catering sector concentrate the most and how far are people, on average, from this location across hours of a day? Are people, on average, closer to the concentration around the prime dinner time? Taking advantage of open and big data, we geovisualised the answers in the context of Beijing, the capital of China, with a population of 22+ million people. Specifically, the data we used were the 2015 points of interest of Baidu Map (the Chinese counterpart of Google Maps) and 10–16 August 2015 cellular network data for Beijing. The former provide us with the number and location of most if not all restaurants around the local metro-served area (MSA) – that is, areas that are within an 800-metre radius of a metro station. The latter allow us to derive the average number of cellular phone users (as a proxy for the general population, residents and/or employees) by MSA across hours of a day. We depict the top five population/employment/residential centres (quantified by the average number of cellular phone users) at three different times of the day, and the top 10 food centres (measured by the number of restaurants) at the MSA level in Beijing.
Evolution of sandstone mesas – following landform decay until death
Authors: Migoń Piotr , Różycka Milena , Jancewicz Kacper , Duszyński Filip
Published: September 2018

Mesas are residual landforms typical for layered rock sequences, formed due to tableland dissection and cliff retreat. Caprock cliffs are characteristic elements of mesa morphology. Mesas have finite lifetimes and over time are reduced in area, transforming into buttes and eventually into irregular arrays of boulders. Thus, they are ‘born’, when separated from a plateau, and ‘die’, when the caprock completely disintegrates. In this paper, sequential development of sandstone-capped mesas is first inferred from theory and then verified on the basis of field observations and landform inventories from a sandstone tableland of the Elbe Sandstone Mountains in the eastern part of Germany. Finally, selected morphometric parameters of mesa morphology, potentially indicative of their evolutionary phases, are computed from a high-resolution digital terrain model. Both field evidence and results of morphometric analysis indicate that mesas evolve along various pathways and, tending towards specific end-members, illustrate the principle of equifinality. Space-for-time substitution, if applied with care, may also be helpful in deciphering the geomorphic history of mesas and tracing their life until disappearance.
How URPE Helped This “Tenured Radical” Thrive in a Non-radical Economics Department
Authors: Meeropol Michael
Published: September 2018

I joined URPE when it was first formed in 1968 and found a strong support group in the Springfield-Northampton-Amherst area of Western Massachusetts when I got my first teaching job. I was at a teaching institution where the Economics program mostly serviced students from the School of Business. Having a support group of like-minded radicals in the early 1970s gave me the confidence and support to develop my own approach to teaching that combined presenting mainstream analysis and making all students aware of the existence and substance of radical alternatives. Those early years of URPE were a heady time—we were involved in struggles to make sure radicals were not purged by hostile departments. We attended conferences and wrote articles and participated in local struggles. Most importantly, unlike, for example, Paul Baran at Stanford University who lamented in a letter to Paul Sweezy that he had “no one to talk to,” we had each other—we had the Review of Radical Political Economics ( RRPE)—and we had visions of changing not just economics but the world. We still need that hope and enthusiasm today.
A family of falsehoods: Deception, media hoaxes and fake news
Authors: Finneman Teri , Thomas Ryan J.
Published: September 2018

“Fake news” became a concern for journalists in 2017 as news organizations sought to differentiate themselves from false information spread via social media, websites and public officials. This essay examines the history of media hoaxing and fake news to help provide context for the current U.S. media environment. In addition, definitions of the concepts are proposed to provide clarity for researchers and journalists trying to explain these phenomena.
Women’s Voices: An Appreciative Inquiry of Off-Site Postsecondary Correctional Education
Authors: Frerich Michelle A. , Murphy-Nugen Amy B.
Published: September 2018

Using an appreciative inquiry method, this study explored the experiences of women who participated in off-site postsecondary correctional education (PSCE). Semistructured interviews were conducted with four women who participated in study release, a program in which women who are incarcerated are permitted to leave the prison facility on a daily basis in order to attend postsecondary education courses at a nearby university or community college. Findings indicate one unifying theme among study participants: the restoration of one’s humanity through participation in PSCE. Connected to this unifying theme are two subthemes: (1) restoration of self and (2) restoration of connection and community. Implications for policy, practice, and research are discussed, including involving women and women’s voices in advocacy efforts to shape correctional policy from a punitive to restorative approach, offering choice of study in PSCE, providing PSCE opportunities that are off-site, fostering connections among PSCE participants and those who support them, and considering measures beyond recidivism to measure PSCE success. Limitations and suggestions for future research are addressed.
Kinematic analysis and dimensional synthesis of a three-degrees-of-freedom hybrid-drive parallel mechanism
Authors: Zhao Xingyu , Zhao Tieshi , Xu Xuehan , Bian Hui , Ding Shixing
Published: September 2018

With the increasing demand for the attitude adjustment and vibration isolation of the precision instruments, this paper proposes a three-degrees-of-freedom hybrid-drive parallel mechanism and carries out the kinematic analysis and dimensional synthesis for it. First, the advantages of the hybrid-drive unit are introduced by comparison with the common driving methods. Then, the degrees of freedom of the hybrid-drive parallel mechanism is analyzed by constrained screw method, and the displacement mapping relationship between the generalized input and the moving platform is obtained by a successive approximation iteration method. Furthermore, the first-order and the second-order influence coefficients of the hybrid-drive mechanism are established on the basis of screw theory and the direct method. Besides, the operational dexterity index, the transfer performance index and the stiffness performance index of the hybrid-drive mechanism are introduced, and each single-objective dimensional synthesis of the hybrid-drive mechanism is carried out by the interior point method. Moreover, the multi-objective dimensional synthesis of the hybrid-drive mechanism is proposed by combining the genetic algorithm and the Pareto-optimal solution. Finally, taking the integer numbers of No.23 Pareto set as the numerical example, the kinematics formulas of the hybrid-drive mechanism are verified by the simulation and the experiment.
A comparison of friction modifier performance using two laboratory test scales
Authors: Buckley-Johnstone L , Harmon M , Lewis R , Hardwick C , Stock R
Published: September 2018

This paper describes two methods, carried out at two different test scales, for assessing the friction modifier performance. Study A used the wear data from a full-scale rig test at the voestalpine Schienen GmbH and compared it with the wear data from twin disc tests using the SUROS test machine at the University of Sheffield. Study B compared the ‘retentivity’ data, from a full-scale rig at the University of Sheffield, with the data from the SUROS tests. Study A concluded that a good correlation existed between the two scales although assumptions made in the full-scale contact calculation introduce a large spread into the results. There was a greater correlation between the two data sets at more severe contact conditions. Study B showed a different baseline coefficient of traction between the two scales and that a longer test length is required to fully evaluate the ‘retention’ of the friction modifier on the full-scale rig. The paper expands on a previous conference presentation on the same subject. Additional information on the test procedure and test rigs is included here. Surface and subsurface analyses of the SUROS test samples have also been added. The analyses have shown that applying the friction modifier leads to a similar wear mechanism as for the dry contact, but the wear is less severe and there is less subsurface deformation. A discussion describing the differences in test scales and comparing lab tests to field operation is also included.
Laboratory fatigue performance of under-ballast mats under varying loads and support conditions
Authors: Lima Arthur de O , Dersch Marcus S , Qian Yu , Tutumluer Erol , Edwards J Riley
Published: September 2018

Primarily being employed in ballasted bridge decks and tunnels, under-ballast mat applications have seen growth in the North American market as a solution to reduce the stress state of the ballast by lowering the track stiffness and reducing ground-borne vibrations. However, the German DIN 45673 standard is currently the sole reference procedure for quantifying under-ballast mat’s mechanical fatigue performance by using real ballast particles as a loading contact interface and is tailored to European loading characteristics. This presents challenges for testing materials intended for North American heavy haul freight lines implementing such procedures. Moreover, large intrinsic variability is present when employing the real ballast material as a loading contact interface. This work presents findings from laboratory mechanical fatigue experiments conducted on under-ballast mat samples based on DIN-recommended procedures. Two loading contact interfaces—ballast box and geometric ballast plate—and two load magnitudes—representing European mainline and North American heavy haul freight loading environments—were applied to the samples in this study. For all tests, no significant physical sample damage was observed after testing. Further, although significant immediate change in bedding modulus was observed for the North American-loaded samples, modulus changes in both test cases were similar when evaluated one week after the completion of the tests. In addition, gradation analysis of the ballast material revealed little impact other than particle surface wear. Finally, results from this work demonstrate that geometric ballast plate is an effective alternative for investigating under-ballast mat’s performance and should be useful for the future development of North American-recommended practices for testing under-ballast mats subjected to heavy haul loads.
An experimental study of binary lateral jets on a standard model in subsonic, transonic, and supersonic cross-flows
Authors: Doolabi Mostafa Hadi , Tavakoli Sabour Seyed Ali
Published: September 2018

There are numerous aerodynamic and nonaerodynamic methods to control flying devices, one of which is lateral jets, i.e. a high-speed method with convenient operation at low speeds or high altitudes. In this research, a new arrangement of lateral jets is examined by testing in a wind tunnel. The test is conducted on the Basic Finner model. In this design, the jets at the top and bottom of the model are arranged in pairs and parallel to each other. This combination, in addition to controlling pitch channel, provides the necessary conditions to control the roll channel. In this paper, pressure distribution is examined in the upstream and downstream areas as well as middle of jets. The flow visualization method is also used. The results are provided for subsonic, transonic, and supersonic free flow regime at the positive and negative angles of attacks. In the subsonic and supersonic flows, the achievements of the binary jets are the further pressure reduction on the middle line of jets compared with the same position at downstream of a single jet, and maintaining a high-pressure area of a single jet at the upstream of jets compared with the upstream area. However, the pressure reduction rate is lower in the transonic regime and the effectiveness of the angle of attack is greater than the subsonic and supersonic flows. Finally, a comparison with numerical result is accomplished.
Synthesis and Adsorption of Organo-Montmorillonite/Poly(Acrylic Acid) Superabsorbent Composite
Authors: Zhu Linhui , Zhang Lili , Tang Yaoji , Yang Jing
Published: September 2018

Organo-montmorillonite /poly (acrylic acid) superabsorbent composite was prepared by intercalation polymerization of acrylic acid (AA) and organo-montmorillonite (OMMT). The composite was characterized by means of Fourier-transform spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Maximum absorbency of OMMT/PAA in distilled water and 0.9% NaCl was 1439 and 97 g/g, respectively. Water retention of the composite was also tested. The composite was used for removal of heavy metal ions from aqueous solutions. The maximum adsorption capacities for Pb2+, Cu2+ and Ni2+ were 1006.97, 280.56 and 165.67 mg/g, respectively, and the adsorption was consistent with the Freundlich model. It was found that the superabsorbent composite showed good re-use performance in wastewater treatment.
The Properties of Melt-Blended Compatibilized Metallocene Polyethylene/Clay Nanocomposites
Authors: Chen Wen-Chih , Lai Sun-Mou , Wang Zi Way , Qiu Rong Yu
Published: September 2018

Although it is well known to employ compatibilizer to assist clay dispersion in thermoplastic/clay systems, the properties of compatibilizers have often been neglected. Metallocene polyethylene (mPE)/clay nanocomposites were prepared via a melt-blending approach to further investigate this compatibilization effect. Maleated mPE (mPE-g-MA) was also prepared as a compatibilizer to improve the dispersion of commercial organoclay. The mPE/mPE-g-MA/clay compatibilized systems showed good dispersion of clay or swollen tactoids through X-ray diffraction (XRD) and transmission electron microscopy (TEM) assessments. The compatibilized cases showed slightly higher crystallization temperatures at higher clay contents than their counterparts without any compatibilizer. The mechanical properties of the investigated systems were rather complex and unusual. The Young's modulus of compatibilized nanocomposites showed slightly higher values in all investigated cases, stemming from the more effective interfacial interaction. The tensile strength of mPE/clay systems increased with increasing clay content; however, that of mPE/mPE-g-MA/clay systems decreased with increasing clay content due to possible heterogeneous microgel (bound polymer) formation in the compatibilized clay. Lower tear strength for compatibilized cases was found, which was attributed to the low tear strength of the compatibilizer and microgel formation, along with the clay moiety serving as inorganic crosslinks to give less energy dissipation during deformation. The results indicated that high dispersion of clay did not guarantee high strength, and the mechanical properties should be carefully evaluated to exploit the reinforcement of nanocomposites.
Thermal and Mechanical Reinforcement of Poly(Methyl Methacrylate) via Incorporation of Polyhedral Oligomeric Silsesquioxane
Authors: Yang Benhong , Li Meng , Wu Yun , Wan Xingliang
Published: September 2018

A series of inorganic/organic nanocomposites were prepared by blending cage-like, hydroxyl-bearing polyhedral oligomeric silsesquioxane (HO–POSS) with poly(methyl methacrylate) (PMMA) in THF solvent. Fourier transform infrared spectrophotometry (FTIR) and 29Si–nuclear magnetic resonance (29Si-NMR) were employed to characterize the structures of the HO–POSS/PMMA nanocomposites. Scanning electron microscope (SEM) images showed that the as-prepared composite films were smooth, and no severe aggregation of HO–POSS was observed when POSS content was less than 1.0 wt.%. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results showed that the incorporation of small amount of nanosized HO–POSS reinforced the thermal stability of PMMA. When 1.0 wt.% of HO–POSS was incorporated into PMMA matrix, the Tg and Td increased by 28.8 °C and 18.9 °C, respectively, due to the strong interaction between POSS cages and PMMA chains. However, higher POSS contents (>2.0 wt.%) deteriorated the thermal and mechanical properties of the nanocomposites owing to the phase separation in the composite matrix caused by the aggregation of POSS cages.
Evaluation of Biological Properties In-Vivo of Poly(L-Lactide-Coglycolide) Composites Containing Bioactive Glass
Authors: Zhou Zhihua , Liu Lihua , Liu Qingquan , Huang Tianlong , Zeng Wennan , Yi Qingfeng , Yang Zhongmin , Cao Dafu
Published: September 2018

To evaluate the biological safety of composite materials based on poly(L-lactide-co-glycolide) (PLGA) and bioactive glass (BG), which have a potential application in tissue engineering, the in-vivo biological properties were investigated by applying the micronucleus test, acute systemic toxicity test, haemolytic test and pyrogen measurement. The results indicated that the PLGA/BG composite showed no genetic toxicity; there was no toxicosis or death observed in the acute systemic toxicity test. The haemolytic test suggested that the PLGA/BG composite, with a haemolytic index of 0.281%, did not have an obvious haemolytic reaction. In addition, the PLGA/BG composite materials showed no pyrogen reaction. Therefore, PLGA/BG composite materials could be promising candidate biomedical materials for bone tissue engineering.
Preparation of a Recombinant Spider Silk Protein/Pcl Blend Submicrofibrous Mat and Its Cytocompatibility
Authors: Zhao Liang , Chen Denglong , Wei Meihong , Yao Qinghua , Li Min
Published: September 2018

With electrospinning technology, recombinant spider silk protein/PCL blend submicrofibrous mat was prepared. Its properties as a potential wound dressing material were evaluated by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). When the proportion of recombinant spider silk protein/polycaprolactone (PCL) reached 1:20, the appropriate concentration of spinning solution was 30%. Also, the fibre diameter increased as the nozzle-to-ground distance decreased, or as the extrusion speed increased. The fibres tended to be non-uniform. As shown by FTIR, PCL and recombinant spider silk protein blended together without obvious molecular interaction. MTT assay analysis showed that, compared with PCL scaffold, the toxic level of pNSR16/PCL composite scaffold was below 1, which meets the criteria for biomaterials. NIH-3T3 cells cultivation on the composite scaffolds indicated that pNSR16/PCL composite scaffolds with RGD had better cell adhesion than PCL scaffolds. Immunohistochemical experiments proved that cells on the pNSR16/PCL composite scaffold materials had no effect on normal growth. pNSR16/PCL composite scaffold guaranteed good crawling capacity of cells.
Production of a Polymeric Composite Material Filled with Halogen-Free Flame Retardant
Authors: Yılmaz Melih Can , Ezdeşir Ayhan , Ulutan Sevgi , Tüzüm-Demir A. Pınar
Published: September 2018

In the present study a composite material to be used in cable industry, which has LDPE/EVA (low density polyethylene/ethylene-vinyl acetate copolymer) polymer blend and alumina trihydrate (ATH) filler, which is a halogen-free flame retardant (HFFR), has been formulated and characterized in terms of its mechanical, rheological and flame retardant properties comparing with the commercial mixtures.

Composite blends having 40% polymer component with various PE/EVA ratio and two PE type and 60% ATH were prepared. As the EVA content of composites increased from 26% to 65% the storage modulus increased by 180-220%, viscosity increases by %61-107. Composites containing 65% EVA exhibit similar properties to the commercial one. Limiting Oxygen Index (LOI) value was found as 30 for composites containing 26 mass% of EVA, it increased to 32-34 when EVA content increased to 65 mass%.
Preparation and Characterization of Flexible Polyvinylchloride-Copper Composite Films
Authors: Kurt Emrah , Özçelik Cenk Yağız , Yetgin Senem , Ömürlü Filiz Özmıhçı , Balköse Devrim
Published: September 2018

Flexible PVC films are statically charged due to their low electrical conductivity. This creates fire threat during its handling. Conductive materials are added to films to prevent this. In the present study it was aimed to prepare PVC- copper composite films by sol gel technique and characterize the prepared films. It was aimed to increase the electrical conductivity of the films by adding copper powder. However, the copper particles settled down to bottom instead of forming a conductive network that covers the whole cross section. Thus at the film cross-section a plastic upper phase and a copper rich lower phase were present. The film did not conduct electricity due to this uneven distribution. The minimum volumetric and surface resistivities of the films were at the order of 109 ohm-cm and 1010 ohm square respectively.
Industrial Plant Application of Hydrophobic Coating on Tile Surface
Authors: Tunali Ayşe , Selli Neslihan Tamsu
Published: September 2018

Nowadays, ceramic tile surface properties such as easy to clean surface is highly demanded by the market. In order to design these new easy to clean-hydrophobic surfaces, nanomaterials and/or hybrid materials will be indispensable. At present, these novel materials are hardly used in ceramic tile manufacturing processes. It is therefore necessary to develop a completely new methodology in order to suitably choose, handle, and incorporate these materials into the ceramic tile surface with a view to obtaining the desired properties.

The aim of this investigation was the industrialization of application of hydrophobic coating on tile surface by choosing appropriate tools and optimizing process parameters. Airtight mixing and spraying tank was designed to prevent gelation of hydrophobic solution during application. Then tile temperature and amount of solution was optimized. It has been observed that hydrophobic coating provide high contact angle without changing surface appearance of tiles.
Adsorption Kinetics Studies of Polymeric Nanocomposite Coagulants
Authors: Uzunsakal Seher , Zeytinci Serhat , Uyanık Ömer L. , Uyanık Nurseli
Published: September 2018

The aim of this study is to investigate the adsorption characteristics of dicyandiamide-formaldehyde resin (DCD-F) nanocomposites. For this purpose, 2%, 4%, and 8% unmodified layered silicate clay (Na-Montmorillonite) containing DCD-F nanocomposites (DCD-F- MMT) were prepared. The synthesized samples were structurally defined by XRD, SEM-EDX, and TGA characterizations. The adsorption performance of nanocomposites was tested by using two anionic dyes. Adsorption capacities of pure resin and three nanocomposites were followed against time and the nanocomposite containing 8% Na-MMT (DCD-F-MMT8%) was found to have the highest equilibrium adsorption capacity (qe). Therefore, the effects of dye concentration, pH, and temperature on qe were investigated using DCD-F-MMT8%. The kinetic and thermodynamic parameters of adsorption were obtained based on the experimental data.
Fabrication of Composite Tiles from Poly(Ethylene Terephthalate) (Pet) and Micro-Marble Particles Reinforced with Glass Fiber Mats: Comparison of Recycled and Commercial Resin
Authors: Icduygu M. Galip , Aktas Levent , Altan M. Cengiz
Published: September 2018

Polyester composite tiles (PCT) are synthesized from PET and fabricated by compression molding using micro-marble clusters as filler. Identical PCTs are also fabricated by using commercially available polyester resin to compare properties. Three batches of marble clusters with different size distributions are used to assess the effect of filler particle size on mechanical properties. Tiles prepared using finer marble grades yield consistently higher flexural strength and stiffness values regardless of the synthesized or commercial polyester resin. However, the flexural strength and stiffness of the tiles prepared with commercial polyester are observed to be on average 1.8 and 2.5 fold higher, respectively. Prospects of improving mechanical properties are explored by reinforcing PC tiles with randomly oriented, discontinuous glass fibers. This is achieved by placing a single layer of glass fiber mat on the top and bottom tile surface. Presence of fiber mats leads to the formation of a graded particle size distribution across the mat thickness when the coarse grade marble dust is used. This distribution resulted in significant improvements in flexural strength, stiffness and overall toughness of the tiles. The improvements observed in PCTs prepared with synthesized polyester resin surpassed the improvements in their counterparts prepared with commercial polyester. In fact, the flexural strength of the glass fiber mat reinforced PCTs prepared with synthesized and commercial polyester resin are observed to be statistically identical.
Synthesis of Poly(Styrene-Co-Acrylonitrile)/Clay Nanocomposites in Supercritical Carbon Dioxide
Authors: Wang Jing , Zhong Jianfeng , Fang Zhou , Dong Qingzhi
Published: September 2018

Poly(styrene-co-acrylonitrile)/fluorinated montmorillonite was successfully prepared in supercritical carbon dioxide (scCO2) by dispersion polymerization. In this study, a mixed stabilizer system was applied and investigated. Poly(styrene-r-acrylonitrile)-block-poly(1,1,2,2-tetrahydroperfluorooctyl methacrylate)(PSAN-b-PFOMA) was synthesized and investigated as stabilizer in scCO2. Fluorinated surfactant was used for the modification of the montmorillonite. The fluorinated montmorillonite (FMMT) applied in the polymerization was not only used as nanocomposite filler but also as a guest stabilizer. This study examined the stabilization roles of stabilizer and guest stabilizer respectively. The optimum dosages of both compounds were studied. The polymerization with mixed stabilizer resulted in high yield and high molecular weight. Moreover, a series of nanocomposites were characterized and the products showed excellent properties. It was found that the montmorillonite layer could be completely exfoliated using reasonable loading, and dispersed in the polymer matrix. In addition, the pressure of scCO2 was studied and the density of scCO2 was shown to be relevant to the stabilization of the reaction. The mixed stabilizer system made the polymerization more effective and the in-situ dispersion polymerization performed in scCO2 was shown to be a useful method for the nanocomposites preparation.
Honeycomb Patterned Sps/Tio2 Hybrid Films Derived from Bf Technique and Gelation
Authors: Song Qiusheng , Zhu Xiaofei , Xu Yuanhao
Published: September 2018

Honeycomb patterned hybrid films were prepared from sulfonated polystyrene (SPS) and tetrabutyl titanate (TBT) by a combination of the “breath figure” technique with a gelation process. The influences of solvents, concentration and the mass ratio of SPS/TBT in the hybrid sols on the morphology of the honeycomb films were investigated. The results from SEM, FTIR, DSC, TG and XRD showed that well-ordered films were formed when benzene was used as solvent, the mass ratios of SPS/TBT in the range of 10/1∼1/2 and the concentration of SPS maintained in the range of 20-80 mg/mL.
Curing Methods for Advanced Polymer Composites - A Review
Authors: Abliz Dilmurat , Duan Yugang , Steuernagel Leif , Xie Lei , Li Dichen , Ziegmann Gerhard
Published: September 2018

Advanced polymer composites have obtained great application interest in a number of demanding aerospace, wind energy, automotive, infrastructure, and consumer applications. Great varieties of curing methods are investigated to develop low-cost and high-efficient fabrication of advanced polymer composites, which still remains as a great challenge and thorny issue. Especially, the autoclave curing process, which is widely used for curing of high performance advanced polymer composites, is labor- and capital-intensive, with costs increasing exponentially with part size and limiting increased use of advanced polymer composites. Researchers and industries have long desired to explore and develop low-cost and high-efficient curing methods for fabrication of advanced polymer composites and investigated different radiation and thermal curing alternatives. In this paper, current development status of the radiation curing (gamma ray, x-ray, ultraviolet, accelerated electron beams) and thermal curing (radiation heating (infrared, laser and microwave), convection and conduction heating (hot gas, flame, oven and hot shoe), induction heating, ultrasonic heating, resistance heating and thermal additives (magnetic particles, NIR absorbent particles) based heating methods applied for the curing of advanced polymer composites are reviewed. The curing mechanism and current application status of the different curing processes for fabrication of advanced polymer composites is discussed, and main advantages and disadvantages of these methods are comparatively analysed and evaluated according to the material, cost, feasibility and power criteria for successful curing application of advanced polymer composites.
Synergistic Effect of SiO2 on Intumescent Flame-retardant Polypropylene
Authors: Li Na , Xia Yin , Mao Zongwen , Wang Liang , Guan Yong , Zheng Anna
Published: September 2018

The flammability of polypropylene and its intumescent flame retardant composites consisting of ammonium polyphosphate (APP), pentaerythritol (PER) and SiO2 were studied and the synergistic effect of SiO2, as well as the synergistic mechanism was discussed in detail. For the composites, the content of SiO2 varied from 0 to 12 wt.% where the total addition of APP/PER/SiO2 was constant at 30 wt.%. The flammability properties were characterized by Limiting Oxygen Index (LOI) and UL-94 tests, while the synergistic mechanism of SiO2 was investigated by a combination of thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectrometry and scanning electron microscopy (SEM). The results showed that SiO2 had a synergistic effect on the PP/APP/PER system, with an optimum addition at 3.5 wt.%. The introduction of SiO2 improved the flame retardant properties of the PP/APP/PER system and the strength of the char layer.
Evaluation of Biological Properties of Collagen/Hyaluronic Acid Composite Scaffolds
Authors: He Zeqiang , Xiong Lizhi
Published: September 2018

Porous collagen matrices crosslinked with hyaluronic acid (HA) by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) have been developed as scaffold materials for tissue engineering. The biological properties, including fibroblast proliferation, haemolytic behaviour, micronucleus, acute toxicity and sensitivity test response, were investigated. Scanning electron microscopy (SEM) morphology demonstrated that the collagen/HA scaffolds had interconnected pores with mean diameters of 100-300 μm. The fibroblast proliferation result indicated that collagen/HA extract could support cell growth and showed a high viability. The haemolytic test suggested that the collagen/HA composite scaffold, with a haemolytic ratio of 0.326-0.776%, did not have any obvious haemolytic reaction. The micronucleus frequency of collagen/HA was (3.2 ± 0.71)‰, which showed no genotoxic effect. The collagen/HA scaffolds showed no acute systemic toxicity, and there was no allergic response in sensitivity test. Therefore, collagen/HA composite materials would be a promising candidates as biomedical materials for tissue engineering.
Materials Selection Strategy and Surface Treatment of Polymer Composites for Wind Turbine Blades Fabrication
Authors: Bassyouni M. , Gutub Saud. A.
Published: September 2018

In the present work the optimal materials selection for wind turbine blades using the Cambridge Engineering Selector (CES) program was carried out. Materials indices were derived, based on the mechanical, physical properties and environmental circumstances. Glass and carbon fibre reinforced plastics (epoxy matrix) showed high materials indices based on combined analysis of power and efficiency, fracture toughness, fatigue and thermal stability. Epoxy-glass fibre (EGF) and epoxy-carbon fibre (ECF) composites were manufactured and investigated. Surface of glass and carbon fibre was chemically modified using gamma-aminopropyltriethoxysilane (Silane A1100) coupling agent. The fibre content was varied between 12 to 70% w/w.

It is found that the addition of (Silane A1100) as a compatibilizer caused further amelioration of the fibre/matrix bonding resulting in improved mechanical behaviour, which was also, assessed using scanning electron microscopy. Mechanical properties of treated and untreated epoxy composites were illustrated using CES program. Tensile strength of EGF composites was varied based on fibres surface treatment and loadings. Tensile strength of silane treated EGF (70% wt/wt) increased to 1.46 GPa comparing with 1.38 GPa of untreated EGF. The potential and applications of this class of composite materials promise a significant opportunity for improving structural properties of wind turbine blades.
Modelling and Prediction of Barrier Properties of Polymer Layered Silicate Nanocomposites
Authors: Mittal Vikas
Published: September 2018

Different permeation models have been compared with the experimental barrier performance of the polyethylene and polypropylene layered-silicate nanocomposites. It was observed that the models assuming the perfect orientation of filler platelets did not represent the nanocomposite system accurately, whereas the models incorporating the misalignment and incomplete filler exfoliation effects were more efficient. Such models also predicted reduction in the barrier performance of the nanocomposites due to saturation of the polymer matrix with the platelets at a particular filler fraction, an observation which was also experimentally confirmed. Further combinations of these models with each other generated additional insights into the nanocomposite systems such as average aspect ratio, extent of filler platelet randomness, relative platelets distance, shape factor and aggregate thickness etc. As a beneficial alternative, modelling and prediction of the barrier performance of the polymer nanocomposites was also demonstrated using the mixture and factorial design methods. Using factorial design methods, aspect ratio as well as percent randomness of the filler platelets in the nanocomposites could be quantified by knowing beforehand the permeation performance and filler volume fraction. Alternatively, by knowing either the aspect ratio or percent randomness revealed the average permeation behaviour in the nanocomposite of known filler volume fraction.
Study on the Synthesis and Antibacterial Properties of Silver-Chitosan Composite
Authors: Bao Yan , Wei Chengrong , Su Enqi , Zhang Qi , Bai Yongxiao
Published: September 2018

The aim of this work was to synthesize a silver-chitosan composite to enhance the antibacterial properties of the composite by using as small an amount of silver as possible. The silver-chitosan composite was prepared using a facile method. The structure character of the silver-chitosan composite was characterized by X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FT-IR). Its antibacterial activities were evaluated by measurements of the minimal inhibition concentration (MIC), inhibition zone diameter and the kinetics of antibacterial activity. The results indicated that silver was connected with the chitosan homogeneously and stably after initiation by potassium persulfate. The composite exhibited high antibacterial activity to Candida albicans with low MIC and relatively low optical density; it also had good antibacterial activity to Escherichia coli with larger inhibition zone diameter.
Curing Kinetics and Thermal Properties of Aromatic Multifunctional Epoxy Resins
Authors: Yu Mingming , Zhou Zhengwei , Lu Hang , Li Aijun , Bai Ruicheng , Sun Jinliang , Ren Musu , Hu Hefeng
Published: September 2018

In order to investigate the relationship between the chemical structure of multifunctional epoxy resins and their properties, two tetrafunctional epoxies with different aromatic rings content in the molecular main chain, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether (4,4'-TGDDE) and N,N,N',N'-tetraglycidyl-2,2-bis[4-(4-aminophenoxy)phenyl]propane (TGBAPP), were cured with 4,4'-diaminodiphenyl ether (4,4'-DDE) and 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), respectively. Then four amine curing systems (TGBAPP/BAPP, TGBAPP/4,4'-DDE, 4,4'-TGDDE/BAPP and 4,4'-TGDDE/4,4'-DDE) were obtained. Additionally, the 4,4'-TGDDE and another TGDDE with m-glycidyl amino, named N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether (3,4'-TGDDE) were cured with methyl nadic anhydride (MNA). Then the anhydride curing systems (4,4'-TGDDE/MNA and 3,4'-TGDDE/MNA) were prepared. The curing kinetics and thermal properties of these systems were studied in detail. The results indicated that the anhydride curing systems exhibited higher curing reactivity than the amine curing systems, and the resins cured with the anhydride showed better thermal properties. Moreover, introducing more aromatic rings into the backbone would decrease the curing reactivity but enhance the thermal property of the multifunctional epoxy resins. And the tetrafunctional epoxy with p-glycidy amino groups had higher curing reactivity than the epoxy with p-glycidy amino groups, and the thermal property of the front epoxy was better.
Evaluation of Pp/Clay Composites as Soundproofing Material
Authors: Yan Jun , Kim Myung-Sub , Kang Kyung-Min , Joo Kyung-Hoon , Kang Yeon-June , Ahn Sung-Hoon
Published: September 2018

Noise should be disappeared or reduced by using soundproofing materials in our daily life. Polypropylene (PP)/Clay composites are interesting because of their physical and mechanical properties dramatically increased by small quantity of clay filled in PP matrix. In this paper, different types of specimens were made at 0.9, 2.9, 4.8, 6.5, 8.2 and 9.9 wt.% of organically modified clay reinforced PP (100 gram) by solvent based techniques. A heating press and laser cutting process were used to create specimens with thickness 3 mm, diameter 29 mm and 100 mm for high and low sound frequency test, respectively. The soundproofing property was measured by sound transmission loss (TL) through impedance tube method. The measured results showed that about 7∼14.8 dB sound TL was increased for 29 mm diameter PP/Clay (6.5 wt.%) composite specimens compared with pure PP at 3200∼6400Hz. And about 3.3∼5.3 dB sound TL was increased for 100 mm diameter PP/Clay (6.5 wt.%) composite specimens compared with pure PP at 520∼640Hz. In addition, mechanical properties of this composite were measured, and TEM images were taken in order to observe the micro-structure for research on relationship between soundproofing property and micromechanism.