WorldWideScience

Sample records for extracting mechanical properties

  1. CMOS-MEMS Test-Key for Extracting Wafer-Level Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Pei-Zen Chang

    2012-12-01

    Full Text Available This paper develops the technologies of mechanical characterization of CMOS-MEMS devices, and presents a robust algorithm for extracting mechanical properties, such as Young’s modulus, and mean stress, through the external electrical circuit behavior of the micro test-key. An approximate analytical solution for the pull-in voltage of bridge-type test-key subjected to electrostatic load and initial stress is derived based on Euler’s beam model and the minimum energy method. Then one can use the aforesaid closed form solution of the pull-in voltage to extract the Young’s modulus and mean stress of the test structures. The test cases include the test-key fabricated by a TSMC 0.18 μm standard CMOS process, and the experimental results refer to Osterberg’s work on the pull-in voltage of single crystal silicone microbridges. The extracted material properties calculated by the present algorithm are valid. Besides, this paper also analyzes the robustness of this algorithm regarding the dimension effects of test-keys. This mechanical properties extracting method is expected to be applicable to the wafer-level testing in micro-device manufacture and compatible with the wafer-level testing in IC industry since the test process is non-destructive.

  2. Antibacterial, mechanical, and barrier properties of sago starch film incorporated with Betel leaves extract.

    Science.gov (United States)

    Nouri, Leila; Mohammadi Nafchi, Abdorreza

    2014-05-01

    The antimicrobial, mechanical and barrier properties and light transmission of sago starch film incorporated with different percentage of Betel leaf extract (5%, 10%, 20%, and 30%) were evaluated. With regard to mechanical properties, tensile strength decreased when the percentage of extract increased. Elongation at break (%) and seal strength (N/m) increased with increasing percentage of extract from 5% to 20%, while decreased for films containing 30% extract due to heterogeneity of films in this percentage. With regard to barrier properties, water vapour and oxygen barrier properties decreased in all samples when percentage of the extract increased. Antimicrobial activity of all the films increased against both Gram positive and Gram negative bacteria as percentage of Betel leaf extract increased, except for Psuedomonas aeruginosa, which was not susceptible at any percentage of the extract. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Antimicrobial, Optical and Mechanical Properties of Chitosan-Starch Films with Natural Extracts.

    Science.gov (United States)

    Lozano-Navarro, Jessica I; Díaz-Zavala, Nancy P; Velasco-Santos, Carlos; Martínez-Hernández, Ana L; Tijerina-Ramos, Beatriz I; García-Hernández, Margarita; Rivera-Armenta, José L; Páramo-García, Ulises; Reyes-de la Torre, Adriana I

    2017-05-05

    Natural extracts possess several kinds of antioxidants (anthocyanins, betalains, thymol, carvacrol, and resveratrol) that have also demonstrated antimicrobial properties. In order to study these properties, extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and resveratrol (from grapes) were obtained. Growth inhibition tests of mesophilic aerobes, coliforms, and fungi were conducted in films prepared from the extracts in accordance with Mexican Official Norms (NOM). Optical properties such as transparency and opacity, mechanical properties, and pH were also analyzed in these materials. The films with beetroot, cranberry, and blueberry extracts demonstrated the best antimicrobial activity against various bacteria and fungi in comparison with unmodified chitosan-starch film. This study shows that the addition of antioxidants improved the antimicrobial performance of these films. It was also found that antimicrobial properties are inherent to the films. These polymers combined with the extracts effectively inhibit or reduce microorganism growth from human and environmental contact; therefore, previous sterilization could be unnecessary in comparison with traditional plastics. The presence of extracts decreased transmittance percentages at 280 and 400 nm, as well as the transparency values, while increasing their opacity values, providing better UV-VIS light barrier properties. Despite diminished glass transition temperatures ( T g), the values obtained are still adequate for food packaging applications.

  4. Antimicrobial, Optical and Mechanical Properties of Chitosan–Starch Films with Natural Extracts

    Science.gov (United States)

    Lozano-Navarro, Jessica I.; Díaz-Zavala, Nancy P.; Velasco-Santos, Carlos; Martínez-Hernández, Ana L.; Tijerina-Ramos, Beatriz I.; García-Hernández, Margarita; Rivera-Armenta, José L.; Páramo-García, Ulises; Reyes-de la Torre, Adriana I.

    2017-01-01

    Natural extracts possess several kinds of antioxidants (anthocyanins, betalains, thymol, carvacrol, and resveratrol) that have also demonstrated antimicrobial properties. In order to study these properties, extracts from cranberry, blueberry, beetroot, pomegranate, oregano, pitaya, and resveratrol (from grapes) were obtained. Growth inhibition tests of mesophilic aerobes, coliforms, and fungi were conducted in films prepared from the extracts in accordance with Mexican Official Norms (NOM). Optical properties such as transparency and opacity, mechanical properties, and pH were also analyzed in these materials. The films with beetroot, cranberry, and blueberry extracts demonstrated the best antimicrobial activity against various bacteria and fungi in comparison with unmodified chitosan–starch film. This study shows that the addition of antioxidants improved the antimicrobial performance of these films. It was also found that antimicrobial properties are inherent to the films. These polymers combined with the extracts effectively inhibit or reduce microorganism growth from human and environmental contact; therefore, previous sterilization could be unnecessary in comparison with traditional plastics. The presence of extracts decreased transmittance percentages at 280 and 400 nm, as well as the transparency values, while increasing their opacity values, providing better UV–VIS light barrier properties. Despite diminished glass transition temperatures (Tg), the values obtained are still adequate for food packaging applications. PMID:28475151

  5. Antimicrobial, Physicochemical, Mechanical, and Barrier Properties of Tapioca Starch Films Incorporated with Eucalyptus Extract

    Directory of Open Access Journals (Sweden)

    M. Rojhan

    2013-11-01

    Full Text Available Starch is found in abundance in nature and it is one of the raw materials used for food packagingbecause of the low price, biodegradability, good mechanical and barrier properties. The recycling ability ofcoating materials was significantly increased by using edible films and coating in comparison to traditionalpackaging and it could be an alternative for synthetic films. In this research, the effect of eucalyptus extract(Aqueous Extract was investigated on tapioca starch films. Tapioca starch films were prepared by castingmethod with addition of eucalyptus extract and a mixture of sorbitol/glycerol (weight ratio of 3 to 1 asplasticizers. Eucalyptus extract incorporated to the tapioca starch films were dried at different concentrations(0, 15, 25, and 35 of total solid under controlled conditions. Physicochemical properties such as waterabsorption capacity (WAC, water vapor permeability (WVP and mechanical properties of the films wereevaluated. Results showed that by increasing the concentration of eucalyptus extract, tensile strength wasincreased from 20.60 to 15.68 (MPa, also elongation was increased from 19.31 to 23.57 (% at break andYoung’s modulus was decreased from 800.31 to 500.32 (MPa. Also incorporation of eucalyptus extract in thestructure of biopolymer increased permeability of water vapor of starch films. Tapioca starch filmsincorporated with eucalyptus extract exhibited excellent antimicrobial activity against E. Coli. In summary,eucalyptus extract improves functional properties of tapioca starch films and this types of films can be used infood packaging.

  6. Extractive and anatomical wood structure effects on mechanical properties of Caoba wood (Swietenia macrophylla King)

    International Nuclear Information System (INIS)

    Arevalo Fuentes Rosven Libardo; Hernandez Roger

    2008-01-01

    The compression tangential to grain of samples of mahogany wood from Peru was examined at different relative humidity levels at 25 Celsius degrade to determine the influence of both extractives and anatomical structure. Matched samples were used to assess the percentage of extractive components by extraction with solvents of increasing polarity: cyclohexane, dichloromethane, acetone, methanol and hot water. Additionally, fourteen anatomical parameters were determined by image analysis. Stepwise regression analysis concluded that mainly anatomical features, such as rays and vessels, rather than extractives, affect the mechanical behaviour of mahogany. These findings are agree with earlier results showing a negative effect of large and multiseriate rays on the mechanical properties of wood when loaded perpendicularly to their long axis. The influence of lumen located extracts soluble in dichloromethane might disallow deformations. Finally, it is postulated that hot water extracts may play a plasticizing role in this species.

  7. Starch-Glycerol Based Edible Film and Effect of Rosella (Hibiscus Sabdariffa Linn Extract and Surimi Dumbo Catfish (Clarias gariepinus Addition on Its Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Endaruji Sedyadi

    2016-10-01

    Full Text Available Effect of Rosella (Hibiscus Sabdariffa Linn Extract and Surimi Dumbo catfish (Clarias gariepinus addition on Starch-Based Edible Film-Glycerol Mechanical Properties has been done. The purpose of this study is to create an active environment-friendly packaging material. Surimi additions are intended to improve the mechanical properties of bioplastics and additions of Rosella extract intended as a bio-indicator of acidity. The method used was Solvent Casting. An amount of surimi and rosella extract varied to obtain the best mechanical properties. The results shows that the addition of surimi and rosella flower extract significantly effect the elongation of Edible films produced up to 27%.

  8. The Effect of Ultrasonic Waves on Sugar Extraction and Mechanical Properties of Sugar Beet

    Directory of Open Access Journals (Sweden)

    K Hedayati

    2013-09-01

    Full Text Available Sugar, which can be extracted from sugar cane and sugar beet, is one of the most important ingredients of food. Conducting more research to increase the extraction efficiency of sugar is necessary due to high production of sugar beet and its numerous processing units in northern Khorasan province. In this research, the effect of temperature, time and the frequency of ultrasonic waves on mechanical properties of sugar beet and its extraction rate of sugar in moisture content of 75% were studied. In this regard, an ultrasonic bath in laboratory scale was used. The studied parameters and their levels were frequency in three levels (zero, 25 and 45 KHz, temperature in three levels (25, 50 and 70 ° C and the imposed time of ultrasonic waves in three levels (10, 20 and 30 min. Samples were prepared using planned experiments and the results were compared with control sugar beet samples. A Saccharimeter was used to measure the concenteration of sugar in samples. Two different types of probe including semi-spherical end and the other one with sharpened edges were used to measure mechanical properties. The studied parameters of frequency, temperature and time showed significant effect on sugar extraction and their resulted effect in optimized levels revealed up to 56% increase in sugar extraction compared with control samples. The obtained values of elastic modulus and shear modulus showed a decreasing trend. The obtained values of total energy of rupture, the total energy of shear, the maximum force of rupture, and the yield point of rupture showed an increasing trend. The frequency had no significant effect on the yield point of rupture and shear force.

  9. Effect of acid- and alkaline-aided extractions on functional and rheological properties of proteins recovered from mechanically separated turkey meat (MSTM).

    Science.gov (United States)

    Hrynets, Yuliya; Omana, Dileep A; Xu, Yan; Betti, Mirko

    2010-09-01

    Functional and rheological characteristics of acid- and alkali-extracted proteins from mechanically separated turkey meat (MSTM) have been investigated. Extractions were carried out at 4 pH values (2.5, 3.5, 10.5, and 11.5). The study demonstrated that alkali and acid extractions resulted in significant (P hardness, chewiness, springiness, and cohesiveness) of recovered proteins were found to be unaffected (P > 0.05) by different extraction pH. The protein extracted at pH 3.5 formed a highly viscoelastic gel network as evidenced by storage modulus (G') values, whereas the gel formed from proteins extracted at pH 10.5 was found to be the weakest. The work also revealed that acid treatments were more effective for removal of total heme pigments from MSTM. Color characteristics of protein isolates were markedly improved compared to the initial material and tended to be better when subjected to acid extractions. Mechanically separated meat is one of the cheapest sources of protein obtained by grinding meat and bones together and forcing the mixture through a perforated drum. The use of mechanically separated turkey meat (MSTM) for the production of further processed poultry products is limited due to its undesirable color and textural properties. Recovery of proteins from MSTM using pH shifting process will help the poultry processors to get better returns and also create opportunity to produce functional food ingredients.

  10. Mechanical properties, phenolic composition and extractability indices of Barbera grapes of different soluble solids contents from several growing areas.

    Science.gov (United States)

    Torchio, Fabrizio; Cagnasso, Enzo; Gerbi, Vincenzo; Rolle, Luca

    2010-02-15

    Phenolic compounds, extractable from grape skins and seeds, have a notable influence on the quality of red wines. Many studies have clearly demonstrated the relationship between the phenolic composition of the grape at harvest time and its influence on the phenolic composition of the red wine produced. In many previous works the evolution of phenolic composition and relative extractability was normally studied on grapes sampled at different times during ripening, but at the same date the physiological characteristics of grape berries in a vineyard are often very heterogeneous. Therefore, the main goal of the study is to investigate the differences among mechanical properties, phenolic composition and relative extractability of Vitis vinifera L. cv Barbera grape berries, harvested at the same date from several vineyards, and calibrated according to their density at three levels of soluble solids (A=235+/-8, B=252+/-8 and C=269+/-8 g L(-1) sugar) with the aim of studying the influence of ripeness stages and growing locations on these parameters. Results on mechanical properties showed that the thickness of the berry skin (Sp(sk)) was the parameter most affected by the different level of sugars in the pulp, while different skin hardnesses, evaluated by the break skin force (F(sk)), were related to the cultivation sites. The latter were also observed to influence the mechanical characteristics of seeds. Generally, the anthocyanin content increased with the level of soluble solids, while the increase in the tannin content of the berry skin and seeds was less marked. However, significant changes in flavanols reactive to vanillin in the seeds were found. The cellular maturity index (EA%) was little influenced by the soluble solids content of grapes. Copyright 2009 Elsevier B.V. All rights reserved.

  11. Kinetic study on ferulic acid production from banana stem waste via mechanical extraction

    Science.gov (United States)

    Zainol, Norazwina; Masngut, Nasratun; Khairi Jusup, Muhamad

    2018-04-01

    Banana is the tropical plants associated with lots of medicinal properties. It has been reported to be a potential source of phenolic compounds such as ferulic acid (FA). FA has excellent antioxidant properties higher than vitamin C and E. FA also have a wide range of biological activities, such as antioxidant activities and anti-microbial activities. This paper presents an experimental and kinetic study on ferulic acid (FA) production from banana stem waste (BSW) via mechanical extraction. The objective of this research is to determine the kinetic parameters in the ferulic acid production. The banana stem waste was randomly collected from the local banana plantation in Felda Lepar Hilir, Pahang. The banana stem juice was mechanically extracted by using sugarcane press machine (KR3176) and further analyzed in high performance liquid chromatography. The differential and integral method was applied to determine the kinetic parameter of the extraction process and the data obtained were fitted into the 0th, 1st and 2nd order of extraction process. Based on the results, the kinetic parameter and R2 value from were 0.05 and 0.93, respectively. It was determined that the 0th kinetic order fitted the reaction processes to best represent the mechanical extraction.

  12. Antidiabetic Properties and Mechanism of Action of Gynura procumbens Water Extract in Streptozotocin-Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Mariam Ahmad

    2010-12-01

    Full Text Available Gynura procumbens (Lour. Merr (family Compositae is cultivated in Southeast Asia, especially Indonesia, Malaysia and Thailand, for medicinal purposes. This study evaluated the in vivo hypoglycemic properties of the water extract of G. procumbens following 14 days of treatment and in vitro in RIN-5F cells. Glucose absorption from the intestines and its glucose uptake in abdominal skeletal muscle were assessed. The antidiabetic effect of water extract of G. procumbens leaves was investigated in streptozotocin-induced diabetic rats. The intraperitoneal glucose tolerance test (IPGTT was performed in diabetic rats treated with G. procumbens water extract for 14 days. In the IPGTT, blood was collected for insulin and blood glucose measurement. After the IPGTT, the pancreases were collected for immunohistochemical study of β-cells of the islets of Langerhans. The possible antidiabetic mechanisms of G. procumbens were assessed through in vitro RIN-5F cell study, intestinal glucose absorption and glucose uptake by muscle. The results showed that G. procumbens significantly decreased blood glucose levels after 14 days of treatment and improved outcome of the IPGTT. However, G. procumbens did not show a significant effect on insulin level either in the in vivo test or the in vitro RIN-5F cell culture study. G. procumbens also showed minimal effects on β-cells of the islets of Langerhans in the pancreas. However, G. procumbens only significantly increased glucose uptake by muscle tissues. From the findings we can conclude that G. procumbens water extract exerted its hypoglycemic effect by promoting glucose uptake by muscles.

  13. Comparative exergy analyses of Jatropha curcas oil extraction methods: Solvent and mechanical extraction processes

    International Nuclear Information System (INIS)

    Ofori-Boateng, Cynthia; Keat Teong, Lee; JitKang, Lim

    2012-01-01

    Highlights: ► Exergy analysis detects locations of resource degradation within a process. ► Solvent extraction is six times exergetically destructive than mechanical extraction. ► Mechanical extraction of jatropha oil is 95.93% exergetically efficient. ► Solvent extraction of jatropha oil is 79.35% exergetically efficient. ► Exergy analysis of oil extraction processes allow room for improvements. - Abstract: Vegetable oil extraction processes are found to be energy intensive. Thermodynamically, any energy intensive process is considered to degrade the most useful part of energy that is available to produce work. This study uses literature values to compare the efficiencies and degradation of the useful energy within Jatropha curcas oil during oil extraction taking into account solvent and mechanical extraction methods. According to this study, J. curcas seeds on processing into J. curcas oil is upgraded with mechanical extraction but degraded with solvent extraction processes. For mechanical extraction, the total internal exergy destroyed is 3006 MJ which is about six times less than that for solvent extraction (18,072 MJ) for 1 ton J. curcas oil produced. The pretreatment processes of the J. curcas seeds recorded a total internal exergy destructions of 5768 MJ accounting for 24% of the total internal exergy destroyed for solvent extraction processes and 66% for mechanical extraction. The exergetic efficiencies recorded are 79.35% and 95.93% for solvent and mechanical extraction processes of J. curcas oil respectively. Hence, mechanical oil extraction processes are exergetically efficient than solvent extraction processes. Possible improvement methods are also elaborated in this study.

  14. Properties of wood-plastic composites (WPCs) reinforced with extracted and delignified wood flour

    Science.gov (United States)

    Yao Chen; Nicole M. Stark; Mandla A. Tshabalala; Jianmin Gao; Yongming Fan

    2014-01-01

    The water sorption and mechanical properties of wood-plastic composites (WPCs) made of extracted and delignified wood flour (WF) has been investigated. WF was prepared by extraction with the solvent systems toluene/ethanol (TE), acetone/water (AW), and hot water (HW), and its delignification was conducted by means of sodium chlorite/acetic acid (AA) solution. A 2 4...

  15. Effects of Green Tea Extract on Physicochemical and Antioxidant Properties of Polyamide Packaging Film

    Directory of Open Access Journals (Sweden)

    Ali Asghar Barzegaran

    2014-08-01

    Full Text Available Polyamide 6 has been widely used in food packaging applications and also green tea contains amounts of antioxidant compounds. The aim of this study was investigation of green tea effects on properties of polyamide packaging polymer. Polyamide 6 was dissolved in methanol which was saturated with calcium chloride. The active packaging film was produced by incorporation of methanol green tea extracts at levels of 2.5, 5, 10 and 20% in polyamide solution by solution casting method. Mechanical and barrier properties of polyamide films were investigated using ASTM standards and antioxidant activity of polyamide films was evaluated using DPPH method. Results indicated that green tea extract increased antioxidant properties and tensile and young modulus of polyamide films. Oxygen and water vapor permeability of films were decreased by incorporation of green tea extract into polyamide matrix. Green tea extract improved barrier and tensile properties of polyamide films, however elongation at break reduced as increasing of green tea extract in polyamide-based films significantly (P<0.05.

  16. Prediction of retained residual stresses in laboratory fracture mechanics specimens extracted from welded components

    International Nuclear Information System (INIS)

    Hurlston, R.G.; Sherry, A.H.; James, P.; Sharples, J.K.

    2015-01-01

    The measurement of weld material fracture toughness properties is important for the structural integrity assessment of engineering components. However, welds can contain high levels of residual stress and these can be retained in fracture mechanics specimens, particularly when machined from non-stress relieved welds. Retained residual stresses can make the measurement of valid fracture toughness properties difficult. This paper describes the results of analytical work undertaken to investigate factors that can influence the magnitude and distribution of residual stresses retained in fracture mechanics specimen blanks extracted from as-welded ferritic and austenitic stainless steel plates. The results indicate that significant levels of residual stress can be retained in specimen blanks prior to notching, and that the magnitude and distribution of stress is dependent upon material properties, specimen geometry and size, and extraction location through the thickness of the weld. Finite element modelling is shown to provide a useful approach for estimating the level and distributions of retained residual stresses. A new stress partitioning approach has been developed to estimate retained stress levels and results compare favourably with FE analysis and available experimental data. The approach can help guide the selection of specimen geometry and machining strategies to minimise the level of residual stresses retained in fracture mechanics specimen blanks extracted from non stress-relieved welds and thus improve the measurement of weld fracture toughness properties. - Highlights: • A simplified method for generating realistic weld residual stresses has been developed. • It has been shown that significant levels of residual stress can be retained within laboratory fracture mechanics specimens. • The level and distribution is dependant upon material, specimen type, specimen size and extraction location. • A method has been developed to allow estimates of the

  17. Antimicrobial and physical-mechanical properties of agar-based films incorporated with grapefruit seed extract.

    Science.gov (United States)

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-02-15

    The use of synthetic petroleum based packaging films caused serious environmental problems due to their difficulty in recycling and poor biodegradability. Therefore, present study was aimed to develop natural biopolymer-based antimicrobial packaging films as an alternative for the synthetic packaging films. As a natural antimicrobial agent, grapefruit seed extract (GSE) has been incorporated into agar to prepare antimicrobial packaging film. The films with different concentrations of GSE were prepared by a solvent casting method and the resulting composite films were examined physically and mechanically. In addition, the films were characterized by FE-SEM, XRD, FT-IR and TGA. The incorporation of GSE caused increase in color, UV barrier, moisture content, water solubility and water vapor permeability, while decrease in surface hydrophobicity, tensile strength and elastic modulus of the films. As the concentration of GSE increased from 0.6 to 13.3 μg/mL, the physical and mechanical properties of the films were affected significantly. The addition of GSE changed film microstructure of the film, but did not influence the crystallinity of agar and thermal stability of the agar-based films. The agar/GSE films exhibited distinctive antimicrobial activity against three test food pathogens, such as Listeria monocytogenes, Bacillus cereus and Escherichia coli. These results suggest that agar/GSE films have potential to be used in an active food packaging systems for maintaining food safety and extending the shelf-life of the packaged food. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Anti-Fatigue Properties of Tartary Buckwheat Extracts in Mice

    Directory of Open Access Journals (Sweden)

    Ping Wei

    2011-07-01

    Full Text Available Anti-fatigue properties of tartary buckwheat extracts (TBE was investigated in male Kunming mice. The animals were divided into four groups. The first group, designated as the control group (control, was administered with distilled water by gavage every day for 28 days. The other three groups, designated as TBE treatment groups, were administered with TBE of 60, 120 and 240 mg/kg body weight, respectively, by gavage every day for 28 days. Exhaustive swimming time, blood lactic acid (BLA, blood urea nitrogen (BUN, tissue glycogen, glutathione peroxidase (GPx and superoxide dismutase (SOD of mice after swimming were determined. The results showed that tartary buckwheat extracts had anti-fatigue properties, which extended the exhaustive swimming time of mice, effectively inhibiting the increase of BLA, decreasing the level of BUN, increasing the tissue glycogen content and the activities of SOD and GPx of mice. However, further study is needed to elucidate the exact mechanism of the effect of TBE on fatigue.

  19. Plant Phenolics: Extraction, Analysis and Their Antioxidant and Anticancer Properties

    Directory of Open Access Journals (Sweden)

    Jin Dai

    2010-10-01

    Full Text Available Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.

  20. Influence of the extraction method and storage time on the physicochemical properties and carotenoid levels of pequi (Caryocar brasiliense Camb. oil

    Directory of Open Access Journals (Sweden)

    Milton Cosme Ribeiro

    2012-06-01

    Full Text Available The objective of this study was to analyze the physicochemical properties and carotenoid levels of pequi oil obtained by different extraction methods and to evaluate the preservation of these properties and pigments during storage time. The pequi oil was obtained by solvent extraction, mechanical extraction, and hot water flotation. It was stored for over 180 days in an amber bottle at ambient conditions. Analyses for the determination of the acidity, peroxide, saponification and iodine values, coloration, total carotenoids, and β-carotene levels were conducted. The oil extraction with solvents produced the best yield and carotenoid levels. The oil obtained by mechanical extraction presented higher acidity (5.44 mg KOH.g-1 and peroxide values (1.07 mEq.kg-1. During the storage of pequi oil, there was an increase in the acidity and the peroxide values, darkening of the oil coloration, and a reduction of the carotenoid levels. Mechanical extraction is the less advantageous method for the conservation of the physicochemical properties and carotenoid levels in pequi oil.

  1. Role of Interfacial Properties of 4-hydroxyquinoline and / or Some Crown Ethers in the Mechanism of Extraction Process

    International Nuclear Information System (INIS)

    Daoud, J.A.; El-Dessouky, S.I.

    2000-01-01

    The interfacial properties of 8-hydroxyquinoline (HOX) and /or some crown ethers; Db 18 C6, 18 C6 and 15 C5 at the chloroform/ nitrate interface were investigated by measuring their interfacial tension using Du Nouy ring method. The data indicate that 18 C6 and 15 C5 have variable effects on the chloroform-nitrate interface according to their concentrations while Db 18 C6 and HOX have nearly no effect at the interface in the investigated concentration range. The mixture of HOX and 18 C6 or 15 C5 showed different trends according to their concentrations. The proposed mechanisms were verified by carrying out Co(II) extraction by HOX-Db 18 C6 mixture in chloroform in the low and high concentration ranges at different interfacial area. The use of benzene instead of chloroform indicate that the nature of diluent has a marked effect on the interfacial properties of 18 C6 and 15 C5 while Db 18 C6 was found to be sparingly soluble in benzene in the investigated concentration range

  2. Silk Fibroin Degradation Related to Rheological and Mechanical Properties.

    Science.gov (United States)

    Partlow, Benjamin P; Tabatabai, A Pasha; Leisk, Gary G; Cebe, Peggy; Blair, Daniel L; Kaplan, David L

    2016-05-01

    Regenerated silk fibroin has been proposed as a material substrate for biomedical, optical, and electronic applications. Preparation of the silk fibroin solution requires extraction (degumming) to remove contaminants, but results in the degradation of the fibroin protein. Here, a mechanism of fibroin degradation is proposed and the molecular weight and polydispersity is characterized as a function of extraction time. Rheological analysis reveals significant changes in the viscosity of samples while mechanical characterization of cast and drawn films shows increased moduli, extensibility, and strength upon drawing. Fifteen minutes extraction time results in degraded fibroin that generates the strongest films. Structural analysis by wide angle X-ray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR) indicates molecular alignment in the drawn films and shows that the drawing process converts amorphous films into the crystalline, β-sheet, secondary structure. Most interesting, by using selected extraction times, films with near-native crystallinity, alignment, and molecular weight can be achieved; yet maximal mechanical properties for the films from regenerated silk fibroin solutions are found with solutions subjected to some degree of degradation. These results suggest that the regenerated solutions and the film casting and drawing processes introduce more complexity than native spinning processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Antioxidant Properties of Crude Extract, Partition Extract, and Fermented Medium of Dendrobium sabin Flower

    Directory of Open Access Journals (Sweden)

    Farahziela Abu

    2017-01-01

    Full Text Available Antioxidant properties of crude extract, partition extract, and fermented medium from Dendrobium sabin (DS flower were investigated. The oven-dried DS flower was extracted using 100% methanol (w/v, 100% ethanol (w/v, and 100% water (w/v. The 100% methanolic crude extract showed the highest total phenolic content (40.33 ± mg GAE/g extract and the best antioxidant properties as shown by DPPH, ABTS, and FRAP assays. A correlation relationship between antioxidant activity and total phenolic content showed that phenolic compounds were the dominant antioxidant components in this flower extract. The microbial fermentation on DS flower medium showed a potential in increasing the phenolic content and DPPH scavenging activity. The TPC of final fermented medium showed approximately 18% increment, while the DPPH of fermented medium increased significantly to approximately 80% at the end of the fermentation. Dendrobium sabin (DS flower showed very good potential properties of antioxidant in crude extract and partition extract as well as better antioxidant activity in the flower fermented medium.

  4. Base excision repair efficiency and mechanism in nuclear extracts are influenced by the ratio between volume of nuclear extraction buffer and nuclei-Implications for comparative studies

    DEFF Research Database (Denmark)

    Akbari, Mansour; Krokan, Hans E

    2012-01-01

    The base excision repair (BER) pathway corrects many different DNA base lesions and is important for genomic stability. The mechanism of BER cannot easily be investigated in intact cells and therefore in vitro methods that reflect the in vivo processes are in high demand. Reconstitution of BER...... using purified proteins essentially mirror properties of the proteins used, and does not necessarily reflect the mechanism as it occurs in the cell. Nuclear extracts from cultured cells have the capacity to carry out complete BER and can give important information on the mechanism. Furthermore......, candidate proteins in extracts can be inhibited or depleted in a controlled way, making defined extracts an important source for mechanistic studies. The major drawback is that there is no standardized method of preparing nuclear extract for BER studies, and it does not appear to be a topic given much...

  5. Platform construction and extraction mechanism study of magnetic mixed hemimicelles solid-phase extraction

    Science.gov (United States)

    Xiao, Deli; Zhang, Chan; He, Jia; Zeng, Rong; Chen, Rong; He, Hua

    2016-12-01

    Simple, accurate and high-throughput pretreatment method would facilitate large-scale studies of trace analysis in complex samples. Magnetic mixed hemimicelles solid-phase extraction has the power to become a key pretreatment method in biological, environmental and clinical research. However, lacking of experimental predictability and unsharpness of extraction mechanism limit the development of this promising method. Herein, this work tries to establish theoretical-based experimental designs for extraction of trace analytes from complex samples using magnetic mixed hemimicelles solid-phase extraction. We selected three categories and six sub-types of compounds for systematic comparative study of extraction mechanism, and comprehensively illustrated the roles of different force (hydrophobic interaction, π-π stacking interactions, hydrogen-bonding interaction, electrostatic interaction) for the first time. What’s more, the application guidelines for supporting materials, surfactants and sample matrix were also summarized. The extraction mechanism and platform established in the study render its future promising for foreseeable and efficient pretreatment under theoretical based experimental design for trace analytes from environmental, biological and clinical samples.

  6. The Virtual Fields Method Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements

    CERN Document Server

    Pierron, Fabrice

    2012-01-01

    The Virtual Fields Method: Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements is the first book on the Virtual Fields Method (VFM), a technique to identify materials mechanical properties from full-field measurements. Firmly rooted with extensive theoretical description of the method, the book presents numerous examples of application to a wide range of materials (composites, metals, welds, biomaterials) and situations (static, vibration, high strain rate). The authors give a detailed training section with examples of progressive difficulty to lead the reader to program the VFM and include a set of commented Matlab programs as well as GUI Matlab-based software for more general situations. The Virtual Fields Method: Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements is an ideal book for researchers, engineers, and students interested in applying the VFM to new situations motivated by their research.  

  7. Complex rheological properties of a water-soluble extract from the fronds of the black tree fern, Cyathea medullaris.

    Science.gov (United States)

    Goh, Kelvin K T; Matia-Merino, Lara; Hall, Christopher E; Moughan, Paul J; Singh, Harjinder

    2007-11-01

    A water-soluble extract was obtained from the fronds of a New Zealand native black tree fern (Cyathea medullaris or Mamaku in Māori). The extract exhibited complex rheological behavior. Newtonian, shear-thinning, shear-thickening, thixotropic, antithixotropic, and viscoelastic behaviors were observed depending on polymer concentration, shear rate, and shear history. The extract also displayed rod-climbing and self-siphoning properties typical of viscoelastic fluids. Such complex rheological properties have been reported in synthetic or chemically modified polymers but are less frequent in unmodified biopolymers. Although Mamaku extract obtained from the pith of the fern has been traditionally used by the Māori in New Zealand for treating wounds and diarrhea among other ailments, this material has never been characterized before. This study reports on the chemical composition of the extract and on its viscoelastic properties through rotational and oscillatory rheological measurements. Explanations of the mechanism behind the rheological properties were based on transient network models for associating polymers.

  8. Organization of extracting molecules of the diamide type: link with the extracting properties?

    International Nuclear Information System (INIS)

    Meridiano, Y.

    2009-02-01

    The aim of these studies is to establish a link between the different organizations of diamide extractants (used in the DIAMEX process) and their extracting properties. The effects of the key parameters leading the liquid-liquid extraction (concentration of extractant, nature of solute, activity of the aqueous phase, nature of the diluent and temperature) are studied: 1) at the supramolecular scale, with the characterization of the extractant organizations by vapor-pressure osmometry (VPO) and small angle neutron and X-ray scattering (SANS/SAXS) experiments; 2) at the molecular scale, with the quantification of the extracted solutes (water, nitric acid, metal nitrate) and the determination of extracted complexes stoichiometries by electro-spray mass spectrometry (ESI-MS) experiments. The DMDOHEMA molecule acts as a classical surfactant and forms aggregates of the reverse micelle type. Taking into account the established supramolecular diagrams, a quantitative link between the extractants structures and their extracting properties has been brought to light. To model the europium nitrate extraction, two approaches have been developed: - an approach based on mass action laws. Extractions equilibria have been proposed taking into account the supramolecular speciation; - an innovative approach considering the extracted ions as adsorbed on a specific surface of the extractant molecule which depends on the extractant organization state. The ion extraction can be considered as a sum of isotherms corresponding to the different states of organization. This approach allows to compare the extraction efficiency of an extracting molecule as a function of its organization state. (author)

  9. Antimicrobial and physical properties of chitosan films incorporated with turmeric extract.

    Science.gov (United States)

    Kalaycıoğlu, Zeynep; Torlak, Emrah; Akın-Evingür, Gülşen; Özen, İlhan; Erim, F Bedia

    2017-08-01

    In this study, the effects of turmeric extract incorporation on the antibacterial and physical properties of the chitosan films were evaluated. Turmeric containing chitosan-based film was produced with casting procedure and cross-linked with sodium sulfate. Mechanical, optical, thermal properties, and water vapor permeability of the films were studied. The addition of turmeric to chitosan film significantly increased the tensile strength of the film and improved the ultraviolet-visible light barrier of the film. Infrared spectroscopy analysis suggested an interaction between the phenolic compounds of the extract and amin group of chitosan. Antimicrobial activity of the chitosan films was studied against Salmonella and Staphylococcus aureus by plate count agar technique and a better antimicrobial activity was observed with turmeric incorporation. Turmeric incorporated chitosan films with enhanced antimicrobial activity and film stiffness can be suggested as a promising application for food packaging. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effect of Extraction Process and Surface Treatment on the mechanical properties in Pineapple Leaf Fibre

    Directory of Open Access Journals (Sweden)

    Ariffin Azrie

    2017-01-01

    Full Text Available Pineapple Leaf Fibre (PALF is a one of the natural fibre that has high potential in the industry. Natural fibres have become the main alternative source in the modern world industry. The objective of this study is to observe the effect chemical treatment using Sodium Hydroxide (NaOH solution on the physical and mechanical properties of pineapple leaf fibre. Different concentration of NaOH solution (2%, 4%, 6%, 8% and different treatment time (1 hour, 3 hour and 5 hour are used for the experiment. The tensile test was conducted to obtain the mechanical properties such as tensile strength, Yong modulus, (E and elongation at break. From the results obtained, NaOH concentration of 6% and five-hour treatment time that was used for treatment showed the higher physical and mechanical properties values. Furthermore, morphology analysis also shows the surface of the fibre at 6% NaOH after five-hour of treatment was in the better condition with good bonding arrangement of the fibre.

  11. Mechanical property characterization of polymeric composites reinforced by continuous microfibers

    Science.gov (United States)

    Zubayar, Ali

    Innumerable experimental works have been conducted to study the effect of polymerization on the potential properties of the composites. Experimental techniques are employed to understand the effects of various fibers, their volume fractions and matrix properties in polymer composites. However, these experiments require fabrication of various composites which are time consuming and cost prohibitive. Advances in computational micromechanics allow us to study the various polymer based composites by using finite element simulations. The mechanical properties of continuous fiber composite strands are directional. In traditional continuous fiber laminated composites, all fibers lie in the same plane. This provides very desirable increases in the in-plane mechanical properties, but little in the transverse mechanical properties. The effect of different fiber/matrix combinations with various orientations is also available. Overall mechanical properties of different micro continuous fiber reinforced composites with orthogonal geometry are still unavailable in the contemporary research field. In this research, the mechanical properties of advanced polymeric composite reinforced by continuous micro fiber will be characterized based on analytical investigation and FE computational modeling. Initially, we have chosen IM7/PEEK, Carbon Fiber/Nylon 6, and Carbon Fiber/Epoxy as three different case study materials for analysis. To obtain the equivalent properties of the micro-hetero structures, a concept of micro-scale representative volume elements (RVEs) is introduced. Five types of micro scale RVEs (3 square and 2 hexagonal) containing a continuous micro fiber in the polymer matrix were designed. Uniaxial tensile, lateral expansion and transverse shear tests on each RVE were designed and conducted by the finite element computer modeling software ANSYS. The formulae based on elasticity theory were derived for extracting the equivalent mechanical properties (Young's moduli, shear

  12. Study the properties of dense hydroxyapatite-extract from cow bone

    International Nuclear Information System (INIS)

    Sri Asliza, M.A.; Zaheruddin, K.; Shahrizal, H.

    2009-01-01

    In this study, natural hydroxyapatite (HA) was extracted from clean cow bone by treatment with NaOH and heating at high temperature before ground into fine powder. The HA powder were than mixed together with binder for several hours. Dense HA were formed in die steel mould by using uniaxially pressing method. Sample was sintered at different temperature 1150, 1200, 1250 and 1300 degree Celsius for several hours. The phases of specimen were identified using X-ray diffraction (XRD). The mechanical properties were analyzed using three-point bending testing and the microstructure was observed by scanning electron microscopy. From XRD results, natural HA shows phase of pure HA up to 1250 degree Celsius and fracture strength results indicated that the mechanical properties of specimen increase as temperature increase. From microstructure observation using SEM, HA specimen shows initial stages of sintering process at temperature 1150 degree Celsius and show changes in microstructure evolution as temperature increase up to 1300 degree Celsius. (author)

  13. Extraction mechanics in lingual orthodontics: Challenges and solutions

    Directory of Open Access Journals (Sweden)

    Tushar M Hegde

    2016-01-01

    Full Text Available The 21st century has witnessed a slow but sure incorporation of lingual orthodontic protocols into the orthodontic mainstream. Extraction mechanics with lingual orthodontic appliance poses challenges to even the most experienced clinician. This article is a case series of three cases treated by extraction mechanics in a detailed and sequential manner.

  14. PDMS Network Structure-Property Relationships: Influence of Molecular Architecture on Mechanical and Wetting Properties

    Science.gov (United States)

    Melillo, Matthew Joseph

    Poly(dimethylsiloxane) (PDMS) is one of the most common elastomers, with applications ranging from sealants and marine-antifouling coatings to medical devices and absorbents for water treatment. Fundamental understanding of how liquids spread on the surface of and absorb into and leach out of PDMS networks is of critical importance for the design and use in another application - microfluidic devices. The growing use of PDMS in microfluidic devices raises the concern that some researchers may use this material without fully understanding all of its advantages, drawbacks, and intricacies. The primary goal of this Ph.D. dissertation is to elucidate PDMS network molecular structure to macroscopic property relationships and to demonstrate how molecular architecture can alter dynamic mechanical and wetting characteristics. We prepare PDMS materials by using vinyl/ tetrakis(dimethylsiloxy)silane (TDSS) and silanol/ tetraethylorthosilicate (TEOS) combinations of PDMS end-groups and crosslinkers as two model systems. Under constant curing conditions, we systematically study the effects of polymer molecular weight, loading of crosslinker, and end-group chemical functionality on the extent of gelation and the dynamic mechanical and water wetting properties of end-linked PDMS networks. The extent of the gelation reaction is determined using the Soxhlet extraction to quantify the amount of material that did and did not participate in the crosslinking reactions, termed the gel and sol fractions, respectively. We use the Miller-Macosko model in conjunction with the gel fraction and precise chemical composition (i.e., stoichiometric ratio and molecular weight) to determine the fractions of elastic and pendant material, the molecular weight between chemical crosslinks, and the average effective functionality of the crosslinker molecule. Based on dynamic mechanical testing, we find that the maximum storage moduli are achieved at optimal stoichiometric conditions in the vinyl

  15. Influence of Codium tomentosum Extract in the Properties of Alginate and Chitosan Edible Films

    Directory of Open Access Journals (Sweden)

    Ana Augusto

    2018-04-01

    Full Text Available The growing search for natural alternatives to synthetic food packaging materials and additives has increased, and seaweed extracts’ bioactivity has made them suitable candidates for incorporation in novel edible films. This study aims to investigate the effect of Codium tomentosum seaweed extract (SE incorporation in alginate and chitosan edible films. Alginate- and chitosan-based films with and without the incorporation of 0.5% SE were characterized according to their physical, optical, mechanical, and thermal properties. Seaweed extract incorporation in chitosan films resulted in an increase of film solubility (50%, elasticity (18%, and decrease of puncture strength (27% and energy at break (39%. In alginate films, the extract incorporation significantly decreased film solubility (6%, water vapour permeability (46%, and elasticity (24%, and had no effect on thermal properties. Depending on the type of application, the addition of SE in edible films can bring advantages for food conservation.

  16. The influence of alkali treatment on banana fibre’s mechanical properties

    Directory of Open Access Journals (Sweden)

    Julio César Mejía Osorio

    2012-01-01

    Full Text Available This work analyses the effect of alkali treatment on the mechanical properties of banana fibre (Musa Paradisiaca. Fibres were extracted from the pseudostem by a defibring machine; they were mercerised and modified by 5% NaOH (w/v alkali treatment. Morphological characterisation showed that treated fibres’ surface was rougher than that of untreated fibres. Mechanical characterisation indicated that Young’s modulus, ultimate tensile strength and strain became decreased by increasing both treated and untreated fibres’ diameter.

  17. Mechanical properties of chemical vapor deposited coatings for fusion reactor application

    International Nuclear Information System (INIS)

    Mullendore, A.W.; Whitley, J.B.; Pierson, H.O.; Mattox, D.M.

    1980-01-01

    Chemical vapor deposited coatings of TiB 2 , TiC and boron on graphite substrates are being developed for application as limiter materials in magnetic confinement fusion reactors. In this application severe thermal shock conditions exist and to do effective thermo-mechanical modelling of the material response it is necessary to acquire elastic moduli, fracture strength and strain to fracture data for the coatings. Four point flexure tests have been conducted from room temperature to 2000 0 C on TiB 2 and boron coated graphite with coatings in tension and compression and the mechanical properties extracted from the load-deflection data. In addition, stress relaxation tests from 500 to 1150 0 C were performed on TiB 2 and TiC coated graphite beams to assess the low levels of plastic deformation which occur in these coatings. Significant differences have been observed between the effective mechanical properties of the coatings and literature values of the bulk properties

  18. Anxiolytic property of hydro-alcohol extract of Lactuca sativa and its effect on behavioral activities of mice.

    Science.gov (United States)

    Harsha, Singapura Nagesh; Anilakumar, Kandangath Raghavan

    2013-01-01

    Lactuca sativa, belonging to the Asteraceae family, is a leafy vegetable known for its medicinal properties. This study aimed to understand the mechanism of Lactuca sativa extract with respect to pharmacological action.We investigated the anxiolytic effects of hydro-alcoholic extract of leaves of Lactuca sativa on mice. The behavioral tests performed on mice models to assess anti-anxiety properties were: open field test (OFT), elevated plus maze test (EPM), elevated T maze test, and marble burying test. Increased locomotor activity and time spent in the "open-arm" were observed in extract fed group. Malondialdehyde (MDA) and nitrite levels were decreased, catalase and glutathione levels were increased in Lactuca sativa treated mice. The data obtained in the present study suggests that the extract of Lactuca sativa can afford significant protection against anxiolytic activity.

  19. Microstructure and Mechanical Properties of Aligned Natural Fibre Composites

    DEFF Research Database (Denmark)

    Rask, Morten

    properties (stiffness-to-density ratio). The perspective of using natural fibres is to have a sustainable, biodegradable, CO2-neutral alternative to glass fibres. However, so far, it has not been possible to take full advantage of the natural fibre properties when using them for composite applications....... Several challenges have to be addressed and solved, many of which pertain to the fact that the fibres are sourced from a natural resource: 1) Inconsistent properties, depending on plant species, growth and harvest conditions, and fibre extraction techniques. 2) Strength values of composites are lower than...... microscopy during tensile tests of small composite specimens. With this technique, 3D images can be obtained with spatial resolution mechanisms have been identified: (i) Interface...

  20. Extracting material response from simple mechanical tests on hardening-softening-hardening viscoplastic solids

    Science.gov (United States)

    Mohan, Nisha

    Compliant foams are usually characterized by a wide range of desirable mechanical properties. These properties include viscoelasticity at different temperatures, energy absorption, recoverability under cyclic loading, impact resistance, and thermal, electrical, acoustic and radiation-resistance. Some foams contain nano-sized features and are used in small-scale devices. This implies that the characteristic dimensions of foams span multiple length scales, rendering modeling their mechanical properties difficult. Continuum mechanics-based models capture some salient experimental features like the linear elastic regime, followed by non-linear plateau stress regime. However, they lack mesostructural physical details. This makes them incapable of accurately predicting local peaks in stress and strain distributions, which significantly affect the deformation paths. Atomistic methods are capable of capturing the physical origins of deformation at smaller scales, but suffer from impractical computational intensity. Capturing deformation at the so-called meso-scale, which is capable of describing the phenomenon at a continuum level, but with some physical insights, requires developing new theoretical approaches. A fundamental question that motivates the modeling of foams is `how to extract the intrinsic material response from simple mechanical test data, such as stress vs. strain response?' A 3D model was developed to simulate the mechanical response of foam-type materials. The novelty of this model includes unique features such as the hardening-softening-hardening material response, strain rate-dependence, and plastically compressible solids with plastic non-normality. Suggestive links from atomistic simulations of foams were borrowed to formulate a physically informed hardening material input function. Motivated by a model that qualitatively captured the response of foam-type vertically aligned carbon nanotube (VACNT) pillars under uniaxial compression [2011,"Analysis of

  1. Mechanical properties and total hydroxycinnamic derivative release of starch/glycerol/Melissa officinalis extract films

    Directory of Open Access Journals (Sweden)

    Letícia Mello Rechia

    2010-09-01

    Full Text Available The aim of this study was to investigate the mechanical properties of starch/glycerol/Melissa officinalis, a topical drug delivery system for labial herpes treatment. Four films were prepared with different concentrations of starch, glycerol, and Melissa officinalis extract. The results revealed that increasing the glycerol concentration in the film reduced elasticity modulus and tensile strength, exhibiting a plasticizing effect. The increase in free volume resulted in increased release of hydroxycinnamic derivatives expressed as rosmarinic acid.O objetivo deste trabalho foi estudar as propriedades mecânicas e o mecanismo de liberação de um sistema tópico de liberação prolongada para o tratamento do Herpes labial a partir de filmes de amido/glicerol/extrato de Melissa officinalis, planta com comprovada atividade antiviral. Foram obtidos quatro filmes poliméricos com diferentes concentrações de amido, glicerol e extrato de Melissa officinalis os quais foram caracterizados mecanicamente e determinado o perfil de liberação de derivados hidroxicinâmicos. Os resultados demonstraram que o aumento da concentração de glicerol no filme produz uma redução no módulo de elasticidade e na tensão de deformação como conseqüência do efeito plastificante. O aumento no volume livre do polímero resultou em aumento da liberação dos derivados hidroxicinâmicos expressos como ácido rosmarínico.

  2. Assessment of structural, thermal, and mechanical properties of portlandite through molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hajilar, Shahin, E-mail: shajilar@iastate.edu [Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011-1066 (United States); Shafei, Behrouz, E-mail: shafei@iastate.edu [Department of Civil, Construction and Environmental Engineering, Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011-1066 (United States)

    2016-12-15

    The structural, thermal, and mechanical properties of portlandite, the primary solid phase of ordinary hydrated cement paste, are investigated using the molecular dynamics method. To understand the effects of temperature on the structural properties of portlandite, the coefficients of thermal expansion of portlandite are determined in the current study and validated with what reported from the experimental tests. The atomic structure of portlandite equilibrated at various temperatures is then subjected to uniaxial tensile strains in the three orthogonal directions and the stress-strain curves are developed. Based on the obtained results, the effect of the direction of straining on the mechanical properties of portlandite is investigated in detail. Structural damage analysis is performed to reveal the failure mechanisms in different directions. The energies of the fractured surfaces are calculated in different directions and compared to those of the ideal surfaces available in the literature. The key mechanical properties, including tensile strength, Young's modulus, and fracture strain, are extracted from the stress-strain curves. The sensitivity of the obtained mechanical properties to temperature and strain rate is then explored in a systematic way. This leads to valuable information on how the structural and mechanical properties of portlandite are affected under various exposure conditions and loading rates. - Graphical abstract: Fracture mechanism of portlandite under uniaxial strain in the z-direction. - Highlights: • The structural, thermal, and mechanical properties of portlandite are investigated. • The coefficients of thermal expansion are determined. • The stress-strain relationships are studied in three orthogonal directions. • The effects of temperature and strain rate on mechanical properties are examined. • The plastic energy required for fracture in the crystalline structure is reported.

  3. Dialkyldithiophosphoric acids - chemical properties and 5f and 4f elements ions extraction

    International Nuclear Information System (INIS)

    Pattee, D.

    1987-09-01

    This work is a contribution to the study of the properties of the dialkyldithiophosphoric acids and of the extraction of the 4f and 5f ions from weakly acidic nitrate and phosphate media. Following a complete bibliographic study, synthesis and purification of the di-2-ethylhexyl-dithiophosphoric acid (HDEHDTP) is studied. It is identified with chemical methods and spectroscopic methods (I.R., N.M.R., V.P.C.); its by products, the di-2-ethylhexyl (monothio) phosphoric acids (HDEHTP, HDEHP) are also identified and characterized. Stability against hydrolysis and radiolysis is determined. The extractive properties are studied for the 4f and 5f ions. The presence of a sulfur donor atom in HDEHDTP makes it inefficient for the extraction of trivalent lanthanides and actinides but brings out a certain selectivity for americium. For HDEHTP, the presence of an oxygen donor atom rubs out any selectivity and the extraction constants are greater. Selectivity of HDEHDTP is increased by TBP (tri-n-butylphosphate) in synergistic mixtures. The mechanism of extraction of hexavalent uranium from phosphoric medium is elucidated. A model is developed by NMR for the micellisation of the sodium salts of HDEHDTP, HDEHTP and HDEHP, and extrapolated it to the trivalent rare earth salts of the acids. The structures are verified by light scattering and low angle X-ray diffraction [fr

  4. Extraction kinetics and properties of proanthocyanidins from pomegranate peel

    Science.gov (United States)

    With an objective of developing a safe and efficient method to extract proanthocyanidins products from pomegranate peel for use in nutraceuticals or as food additives, the effects of extraction parameters on the production efficiency, product properties, and extraction kinetics were systematically s...

  5. Task-specific ionic liquids for An and Ln extraction: unusual speciation and extraction mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Billard, Isabelle; Jobin, Emilie; Ouadi, Ali; Gaillard, Clotilde [IPHC-DRS, Chimie nucleaire, 23 rue du Loess, BP28, 67037 Strasbourg cedex 2 (France)

    2008-07-01

    Extraction mechanisms of uranium by TBP (tributylphosphate) diluted in an ionic liquid BumimTf{sub 2}N (1-butyl-3-methyl-imidazolium bis(tri-fluoro-methyl-sulfonyl)imide) and by Task-Specific Ionic Liquids (TSILs) bearing a phosphoryl group were investigated. Great differences between these mechanisms and the one in the industrial solvent, dodecane, have been put in evidence. While in dodecane, the neutral species, UO{sub 2}(NO{sub 3}){sub 2}(TBP){sub 2}, is the major extracted complex, in BumimTf{sub 2}N and TSILs, at least two species are extracted with more or less similar proportions. Moreover, no uranyl species with two nitrates could be observed in these ionic liquids. Finally, the mechanisms vary from TBP in BumimTf{sub 2}N to TSILs. These results led to a so-to-say new kind of actinide chemistry. (authors)

  6. PHYSICAL AND MECHANICAL PROPERTIES OF Araucaria angustifolia (Bertol. WOOD FOR THREE STRATUM PHYTOSOCIOLOGICAL

    Directory of Open Access Journals (Sweden)

    Rafael Beltrame

    2010-11-01

    Full Text Available The study of physical and mechanical properties of wood is essential for industrial use both in construction and the manufacture of furniture. Thus, the study aimed to determine the physical and mechanical properties of the Araucaria angustifolia wood in terms of three strata phytosociological. For this, 15 trees were felled, five belonging to the upper stratum, the middle stratum five and five for the lower strata. The trees were deployed for the preparation of specimens used for mechanical testing. In the mechanical characterization of the species assays were performed for impact resistance, static bending, compression axial and perpendicular to the fibers. As for the characterization of physical properties, determined the apparent specific gravity at 12% relative humidity for each extract. The results did not show significant differences in the tests of impact resistance and static bending to the strata phytosociological. As for the apparent specific gravity, compression axial and perpendicular there was a change in the values of propertiesbetween the strata phytosociological, is generally butter in the middle and upper strata. Therefore the physical and mechanical properties tend to present higher values these two strata. The data analysis allowed of Araucaria angustifolia wood has moderate mechanical strength when compared with other species studies.

  7. Effect of tooth bleaching agents on protein content and mechanical properties of dental enamel.

    Science.gov (United States)

    Elfallah, Hunida M; Bertassoni, Luiz E; Charadram, Nattida; Rathsam, Catherine; Swain, Michael V

    2015-07-01

    This study investigated the effect of two bleaching agents, 16% carbamide peroxide (CP) and 35% hydrogen peroxide (HP), on the mechanical properties and protein content of human enamel from freshly extracted teeth. The protein components of control and treated enamel were extracted and examined on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Marked reduction of the protein matrix and random fragmentation of the enamel proteins after bleaching treatments was found. The mechanical properties were analyzed with Vickers indentations to characterize fracture toughness, and nanoindentation to establish enamel hardness, elastic modulus and creep deformation. Results indicate that the hardness and elastic modulus of enamel were significantly reduced after treatment with CP and HP. After bleaching, the creep deformation at maximum load increased and the recovery upon unloading reduced. Crack lengths of CP and HP treated enamel were increased, while fracture toughness decreased. Additionally, the microstructures of fractured and indented samples were examined with field emission gun scanning electron microscopy (FEG-SEM) showing distinct differences in the fracture surface morphology between pre- and post-bleached enamel. In conclusion, tooth bleaching agents can produce detrimental effects on the mechanical properties of enamel, possibly as a consequence of damaging or denaturing of its protein components. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. On Extracting Mechanical Properties from Nanoindentation at Temperatures up to 1000$^{\\circ}$C

    OpenAIRE

    Gibson, James S. K. -L.; Schröders, Sebastian; Zehnder, Christoffer; Korte-Kerzel, Sandra

    2017-01-01

    Alloyed MCrAlY bond coats, where M is usually cobalt and/or nickel, are essential parts of modern turbine blades, imparting environmental resistance while mediating thermal expansivity differences. Nanoindentation allows the determination of their properties without the complexities of traditional mechanical tests, but was not previously possible near turbine operating temperatures. Here, we determine the hardness and modulus of CMSX-4 and an Amdry-386 bond coat by nanoindentation up to 1000$...

  9. Study of the extraction properties of a malonamide-based solid extractant for the separation of lanthanides and actinides

    International Nuclear Information System (INIS)

    Sulakova, Jana; Nash, Kenneth L.; Alexandratos, Spiros D.; Yijia, Yang

    2011-01-01

    The properties of a TMMA-PVB solid extractant, where tetramethyl malonamide (TMMA) as the extracting agent is bonded by covalent boding to polyvinyl benzene (PVB), for the extraction of 154 Eu, 241 Am, 237 Np, 238 U and 232 Th from nitric acid solutions were investigated. The weight distribution coefficients D g were determined across a wide range of HNO 3 concentrations. Low HNO 3 concentrations have a negligible effect on the extraction, whereas high concentrations reduce the extraction properties. One gram of the material was found to bind approximately 1.5 mmol 154 Eu and 1.7 mmol 238 U. (P.A.)

  10. Mechanical properties of the macaw palm fruit-rachilla system

    Directory of Open Access Journals (Sweden)

    Nara Silveira Velloso

    2017-06-01

    Full Text Available The fruit of the native macaw palm [Acrocomia aculeata (lacq Lood. ex Mart] is an alternative for biodiesel production because of the plant characteristics, as well as its adaptability, hardiness and high vegetable oil yield. However, its exploitation remains extractive and there are significant difficulties in its harvest. This study aimed to determine the mechanical properties of the macaw palm fruit-rachilla system that will support the design of harvest machines based on mechanical vibration. Ten samples of four accessions in the immature and mature stages of maturity were used. Traction and vibration tests were conducted to determine the mechanical properties of the macaw palm fruit-rachilla system. The elastic modulus of the rachilla was 188.39-385.09 MPa for the immature stage and 109.02-320.54 MPa for the mature stage. The Poisson's ratio for the rachilla varied between 0.20 and 0.52 for the immature stage and between 0.16 and 0.52 for the mature stage. The damping ratio varied between 0.02 and 0.12 for the immature stage and between 0.06 and 0.12 for the mature stage. The fruit-rachilla system was characterized as underdamped.

  11. Effects of water infusions on mechanical properties of carboniferous rocks

    Energy Technology Data Exchange (ETDEWEB)

    Vavro, M; Chlebik, J

    1977-01-01

    Method of water infusion is used in the Ostrava-Karvina coal region in Czechoslovakia, where the roof of the extracted coal seam consists of thick rock layers (sandstone, Namurian B series) characterized by high resistance to compression, high coefficient of linear elasticity and high capacity of accumulating energy. When the resistance boundary is crossed and the rocks are disturbed this energy is suddenly released and transferred to the surrounding rock masses, coal seam and support system. On the basis of laboratory experiments the physico-mechanical and energy properties of carboniferous rocks together with calculation of their energy coefficient and other parameters are described and calculated. The results of research and theoretical solutions are presented. Practical use of water infusions to influence mechanical properties of sandstone in the roof of coal seams is described with the example of the Dukla coal mine. (5 refs.) (In Polish)

  12. Martensite and bainite in steels: transformation mechanism and mechanical properties

    International Nuclear Information System (INIS)

    Bhadeshia, H.K.D.H.

    1997-01-01

    Many essential properties of iron alloys depend on what actually happens when one allotropic form gives way to another, i.e. on the mechanism of phase change. The dependence of the mechanical properties on the atomic mechanism by which bainite and martensite grow is the focus of this paper. The discussion is illustrated in the context of some common engineering design parameters, and with a brief example of the inverse problem in which the mechanism may be a function of the mechanical properties. (orig.)

  13. IMMUNO-MODULATORY PROPERTIES OF PREBIOTICS EXTRACTED FROM vernonia amygdalina.

    Science.gov (United States)

    Im, Ezeonu; Ae, Asuquo; Bn, Ukwah; Po, Ukoha

    2016-01-01

    Vernonia amygdalina , commonly called bitter-leaf, is widely consumed in many parts of Africa, and Nigeria, in particular. The leaf extract has been reported to have antimicrobial, anti-plasmodial, anti-helminthic, as well as prebiotic properties, but its immuno-modulatory effects have not been well-studied, neither have the prebiotics been identified. This study evaluated the immuno-modulatory properties of the aqueous leaf extract and identified the prebiotic components. The immuno-modulatory potential was evaluated by monitoring the effects of oral administration of the extract on immunological, haematological and lipid profiles of Rattus norvegicus , while the prebiotic components were identified by thin layer chromatography (TLC), following liquid-liquid fractionation of the extract. Consumption of the extract caused significant increases in CD4+-, white blood cell-, total lymphocyte- and high density lipid (HDL) counts; decreases in low density lipid (LDL) and triglycerides and no significant effect on haemoglobin (Hb) and packed cell volume (PCV) in the blood of test animals. The water-soluble fraction of the extract contained most of the phyto-constituents of the extract and Thin Layer Chromatographic analysis of the fraction revealed the presence of fructo-oligosaccharide and galacto-oligosaccharide prebiotics. The results from this study have shown that the aqueous leaf extract of V. amygdalina has positive immune-modulatory and haematologic effects and contains some important prebiotic compounds.

  14. Self-assembling properties of malonamide extractants used in separation processes

    International Nuclear Information System (INIS)

    Testard, F.; Bauduin, P.; Abecassis, B.; Martinet, L.; Berthon, L.; Madic, C.; Zemb, Th.

    2008-01-01

    A review of the four microstructures present in oil phases of malonamide extractants used for nuclear fuel reprocessing is presented in relation with the extraction properties and the third phase formation. Due to their surface active properties, extractants can be considered as a weak surfactants and are organised into reverse micelles interacting through an attractive potential. The Van der Waals attractions between the cores of reverse micelles are the key parameters for understanding ''third phase'' formation. Extractant solutions are similar to reverse microemulsions and the stability rules known in the field of microemulsions can be applied. In some cases, micelles are transformed into a regular molecular solution by modest heating. Apart from micellar and regular solutions, two new modes of association of extractant molecules have been identified. Networks of H-bounds are obtained when ''modifiers'' such as octanol are added by formulators in order to improve stability range. Microphase separation in a more crystalline phase may be obtained by increasing extractant and/or ion concentrations. (orig.)

  15. Effect of mucin extraction method on some properties of ...

    African Journals Online (AJOL)

    Effect of mucin extraction method on some properties of metronidazole mucoadhesive loaded patches. MI Arhewoh, SO Eraga, PF Builders, MA Ibobiri. Abstract. To evaluate the effects of mucin extraction method and plasticizer concentration on the bioadhesive strength and metronidazole release profile from mucin-based ...

  16. Base excision repair efficiency and mechanism in nuclear extracts are influenced by the ratio between volume of nuclear extraction buffer and nuclei—Implications for comparative studies

    International Nuclear Information System (INIS)

    Akbari, Mansour; Krokan, Hans E.

    2012-01-01

    Highlights: • We examine effect of volume of extraction buffer relative to volume of isolated nuclei on repair activity of nuclear extract. • Base excision repair activity of nuclear extracts prepared from the same batch and number of nuclei varies inversely with the volume of nuclear extraction buffer. • Effect of the volume of extraction buffer on BER activity of nuclear extracts can only be partially reversed after concentration of the more diluted extract by ultrafiltration. - Abstract: The base excision repair (BER) pathway corrects many different DNA base lesions and is important for genomic stability. The mechanism of BER cannot easily be investigated in intact cells and therefore in vitro methods that reflect the in vivo processes are in high demand. Reconstitution of BER using purified proteins essentially mirror properties of the proteins used, and does not necessarily reflect the mechanism as it occurs in the cell. Nuclear extracts from cultured cells have the capacity to carry out complete BER and can give important information on the mechanism. Furthermore, candidate proteins in extracts can be inhibited or depleted in a controlled way, making defined extracts an important source for mechanistic studies. The major drawback is that there is no standardized method of preparing nuclear extract for BER studies, and it does not appear to be a topic given much attention. Here we have examined BER activity of nuclear cell extracts from HeLa cells, using as substrate a circular DNA molecule with either uracil or an AP-site in a defined position. We show that BER activity of nuclear extracts from the same batch of cells varies inversely with the volume of nuclear extraction buffer relative to nuclei volume, in spite of identical protein concentrations in the BER assay mixture. Surprisingly, the uracil–DNA glycosylase activity (mainly UNG2), but not amount of UNG2, also correlated negatively with the volume of extraction buffer. These studies demonstrate

  17. Comprehension of synergistic mechanisms for uranium extraction from phosphate ores

    International Nuclear Information System (INIS)

    Pecheur, Olivia

    2014-01-01

    Uranium VI is commonly extracted from phosphoric ores by a well-known process exploiting the synergistic mixture of two extractant molecules: HDEHP and TOPO. In the field of liquid-liquid extraction, synergistic combinations are common but the mechanisms at the origin of the synergy are not well understood. A multi-scale approach has been used to describe these mechanisms, combining two different descriptions: the molecular scale focuses on the ion point of view, while the supramolecular scale focuses on extractants' aggregation. These two approaches have been rationalized by molecular dynamics computations. The results allow describing the synergy through the structure of the complexes and aggregates. With the same approach, some bifunctional compounds, combining the two extracting sites in one molecule, have been studied and compared to the HDEHP/TOPO system in order to identify the origin of their increased capacities in extraction and selectivity. (author) [fr

  18. Antioxidant Properties of Berberis aetnensis C. Presl (Berberidaceae Roots Extract and Protective Effects on Astroglial Cell Cultures

    Directory of Open Access Journals (Sweden)

    Agata Campisi

    2014-01-01

    Full Text Available Berberis aetnensis C. Presl (Berberidaceae is a bushy-spiny shrub common on Mount Etna (Sicily. We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

  19. Antioxidant properties of Berberis aetnensis C. Presl (Berberidaceae) roots extract and protective effects on astroglial cell cultures.

    Science.gov (United States)

    Campisi, Agata; Acquaviva, Rosaria; Bonfanti, Roberta; Raciti, Giuseppina; Amodeo, Andrea; Mastrojeni, Silvana; Ragusa, Salvatore; Iauk, Liliana

    2014-01-01

    Berberis aetnensis C. Presl (Berberidaceae) is a bushy-spiny shrub common on Mount Etna (Sicily). We demonstrated that the alkaloid extract of roots of B. aetnensis C. Presl contains prevalently berberine and berbamine, possesses antimicrobial properties, and was able to counteract the upregulation evoked by glutamate of tissue transglutaminase in primary rat astroglial cell cultures. Until now, there are no reports regarding antioxidant properties of B. aetnensis C. Presl collected in Sicily. Air-dried, powdered roots of B. aetnensis C. Presl were extracted, identified, and quantified by HPLC. We assessed in cellular free system its effect on superoxide anion, radicals scavenging activity of antioxidants against free radicals like the 1,1-diphenyl-2-picrylhydrazyl radical, and the inhibition of xanthine oxidase activity. In primary rat astroglial cell cultures, exposed to glutamate, we evaluated the effect of the extract on glutathione levels and on intracellular production of reactive oxygen species generated by glutamate. The alkaloid extract of B. aetnensis C. Presl inhibited superoxide anion, restored to control values, the decrease of GSH levels, and the production of reactive oxygen species. Potent antioxidant activities of the alkaloid extract of roots of B. aetnensis C. Presl may be one of the mechanisms by which the extract is effective against health disorders associated to oxidative stress.

  20. Evaluation of mechanism for antihypertensive and vasorelaxant effects of hexanic and hydroalcoholic extracts of celery seed in normotensive and hypertensive rats

    Directory of Open Access Journals (Sweden)

    Faezeh Tashakori-Sabzevar

    Full Text Available ABSTRACT Celery (Apium graveolens L., Apiaceae is one of the popular aromatic vegetables and part of the daily diet around the world. In this study, aqueous-ethanolic and hexane extracts of celery seed were prepared and the amount of n-butylphthalide, as an active component, was determined in each extract. Then the effects of hexanic extract on systolic, diastolic, mean arterial blood pressure and heart rate were evaluated in an invasive rat model. The vasodilatory effect and possible mechanisms of above mentioned extracts on aorta ring were also measured. High performance liquid chromatography analysis revealed that hexanic extract contains significantly higher amounts of n-butylphthalide, compared to aqueous-ethanolic extract. The results indicated that hexanic extract significantly decreased the systolic, diastolic, mean arterial blood pressure and heart rate in normotensive and hypertensive rats. Our data revealed that celery seed extract exerts its hypotensive effects through its bradycardic and vasodilatory properties. Moreover, the active components in celery seed extracts could induce their vasodilatory properties through Ca2+ channel blocking activity in endothelial and non-endothelial pathways and particularly by interference with the extra or intracellular calcium.

  1. Mechanical properties of rock at high temperatures

    International Nuclear Information System (INIS)

    Kinoshita, Naoto; Abe, Tohru; Wakabayashi, Naruki; Ishida, Tsuyoshi.

    1997-01-01

    The laboratory tests have been performed in order to investigate the effects of temperature up to 300degC and pressure up to 30 MPa on the mechanical properties of three types of rocks, Inada granite, Sanjoume andesite and Oya tuff. The experimental results indicated that the significant differences in temperature dependence of mechanical properties exist between the three rocks, because of the difference of the factors which determine the mechanical properties of the rocks. The effect of temperature on the mechanical properties for the rocks is lower than that of pressure and water content. Temperature dependence of the mechanical properties is reduced by increase in pressure in the range of pressure and temperature investigated in this paper. (author)

  2. Are extracted materials truly representative of original samples? Impact of C18 extraction on CDOM optical and chemical properties

    Directory of Open Access Journals (Sweden)

    Andrea A Andrew

    2016-02-01

    Full Text Available Some properties of dissolved organic matter (DOM and chromophoric dissolved organic matter (CDOM can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB and the Equatorial Atlantic Ocean (EAO. Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4.C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission and quantum yield of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters.

  3. Are Extracted Materials Truly Representative of Original Samples? Impact of C18 Extraction on CDOM Optical and Chemical Properties.

    Science.gov (United States)

    Andrew, Andrea A; Del Vecchio, Rossana; Zhang, Yi; Subramaniam, Ajit; Blough, Neil V

    2016-01-01

    Some properties of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction (SPE) is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB) and the Equatorial Atlantic Ocean (EAO). Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4). C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission, and quantum yield) of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure) of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters.

  4. Are extracted materials truly representative of original samples? Impact of C18 extraction on CDOM optical and chemical properties

    Science.gov (United States)

    Andrew, Andrea; Del Vecchio, Rossana; Zhang, Yi; Subramaniam, Ajit; Blough, Neil

    2016-02-01

    Some properties of dissolved organic matter (DOM) and chromophoric dissolved organic matter (CDOM) can be easily measured directly on whole waters, while others require sample concentration and removal of natural salts. To increase CDOM content and eliminate salts, solid phase extraction is often employed. Biases following extraction and elution are inevitable, thus raising the question of how truly representative the extracted material is of the original. In this context, we investigated the wavelength dependence of extraction efficiency for C18 cartridges with respect to CDOM optical properties using samples obtained from the Middle Atlantic Bight (MAB) and the Equatorial Atlantic Ocean (EAO). Further, we compared the optical changes of C18 extracts and the corresponding whole water following chemical reduction with sodium borohydride (NaBH4). C18 cartridges preferentially extracted long-wavelength absorbing/emitting material for samples impacted by riverine input. Extraction efficiency overall decreased with offshore distance away from riverine input. Spectral slopes of C18-OM samples were also almost always lower than those of their corresponding CDOM samples supporting the preferential extraction of higher molecular weight absorbing material. The wavelength dependence of the optical properties (absorption, fluorescence emission and quantum yield) of the original water samples and their corresponding extracted material were very similar. C18 extracts and corresponding water samples further exhibited comparable optical changes following NaBH4 reduction, thus suggesting a similarity in nature (structure) of the optically active extracted material, independent of geographical locale. Altogether, these data suggested a strong similarity between C18 extracts and corresponding whole waters, thus indicating that extracts are representative of the CDOM content of original waters.

  5. Effects of Green Tea Extract on Physicochemical and Antioxidant Properties of Polyamide Packaging Film

    OpenAIRE

    Ali Asghar Barzegaran; Maryam Jokar; Majid Javanmard Dakheli

    2014-01-01

    Polyamide 6 has been widely used in food packaging applications and also green tea contains amounts of antioxidant compounds. The aim of this study was investigation of green tea effects on properties of polyamide packaging polymer. Polyamide 6 was dissolved in methanol which was saturated with calcium chloride. The active packaging film was produced by incorporation of methanol green tea extracts at levels of 2.5, 5, 10 and 20% in polyamide solution by solution casting method. Mechanical and...

  6. Extraction of copper zinc and iron from hydrochloric acid solutions by means of different extractants

    Energy Technology Data Exchange (ETDEWEB)

    Zhivkova, Svetlana [Institute of Chemical Engineering - Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2011-07-01

    The extraction of copper, zinc and iron from hydrochloric acid solutions has been studied. The experiments have been carried out using various solvents, involving different extraction mechanisms – solvating, anion-exchange, cation-exchange, bifunctional . Mixtures of these extractants have been also used. The extraction properties of these extractant mixtures toward copper, zinc and iron, the effect of used modifiers and diluents have been also investigated. Key words: Copper, Zinc, Iron, Extraction, Extractant, Modifier, Diluent.

  7. Stacking order dependent mechanical properties of graphene/MoS{sub 2} bilayer and trilayer heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Elder, Robert M., E-mail: robert.elder26.ctr@mail.mil, E-mail: mahesh.neupane.ctr@mail.mil; Neupane, Mahesh R., E-mail: robert.elder26.ctr@mail.mil, E-mail: mahesh.neupane.ctr@mail.mil; Chantawansri, Tanya L. [U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)

    2015-08-17

    Transition metal dichalcogenides (TMDC) such as molybdenum disulfide (MoS{sub 2}) are two-dimensional materials that show promise for flexible electronics and piezoelectric applications, but their weak mechanical strength is a barrier to practical use. In this work, we perform nanoindentation simulations using atomistic molecular dynamics to study the mechanical properties of heterostructures formed by combining MoS{sub 2} with graphene. We consider both bi- and tri-layer heterostructures formed with MoS{sub 2} either supported or encapsulated by graphene. Mechanical properties, such as Young's modulus, bending modulus, ultimate tensile strength, and fracture strain, are extracted from nanoindentation simulations and compared to the monolayer and homogeneous bilayer systems. We observed that the heterostructures, regardless of the stacking order, are mechanically more robust than the mono- and bi-layer MoS{sub 2}, mainly due to the mechanical reinforcement provided by the graphene layer. The magnitudes of ultimate strength and fracture strain are similar for both the bi- and tri-layer heterostructures, but substantially larger than either the mono- and bi-layer MoS{sub 2}. Our results demonstrate the potential of graphene-based heterostructures to improve the mechanical properties of TMDC materials.

  8. Development of a pericardial acellular matrix biomaterial: biochemical and mechanical effects of cell extraction.

    Science.gov (United States)

    Courtman, D W; Pereira, C A; Kashef, V; McComb, D; Lee, J M; Wilson, G J

    1994-06-01

    There is evidence to suggest that the cellular components of homografts and bioprosthetic xenografts may contribute to calcification or immunogenic reactions. A four-step detergent and enzymatic extraction process has been developed to remove cellular components from bovine pericardial tissue. The process results in an acellular matrix material consisting primarily of elastin, insoluble collagen, and tightly bound glycosaminoglycans. Light and electron microscopy confirmed that nearly all cellular constituents are removed without ultrastructural evidence of damage to fibrous components. Collagen denaturation temperatures remained unaltered. Biochemical analysis confirmed the retention of collagen and elastin and some differential extraction of glycosaminoglycans. Low strain rate fracture testing and high strain rate viscoelastic characterization showed that, with the exception of slightly increased stress relaxation, the mechanical properties of the fresh tissue were preserved in the pericardial acellular matrix. Crosslinking of the material in glutaraldehyde or poly(glycidyl ether) produced mechanical changes consistent with the same treatments of fresh tissue. The pericardial acellular matrix is a promising approach to the production of biomaterials for heart valve or cardiovascular patching applications.

  9. Loss of mechanical properties in vivo and bone-implant interface strength of AZ31B magnesium alloy screws with Si-containing coating.

    Science.gov (United States)

    Tan, Lili; Wang, Qiang; Lin, Xiao; Wan, Peng; Zhang, Guangdao; Zhang, Qiang; Yang, Ke

    2014-05-01

    In this study the loss of mechanical properties and the interface strength of coated AZ31B magnesium alloy (a magnesium-aluminum alloy) screws with surrounding host tissues were investigated and compared with non-coated AZ31B, degradable polymer and biostable titanium alloy screws in a rabbit animal model after 1, 4, 12 and 21weeks of implantation. The interface strength was evaluated in terms of the extraction torque required to back out the screws. The loss of mechanical properties over time was indicated by one-point bending load loss of the screws after these were extracted at different times. AZ31B samples with a silicon-containing coating had a decreased degradation rate and improved biological properties. The extraction torque of Ti6Al4V, poly-l-lactide (PLLA) and coated AZ31B increased significantly from 1week to 4weeks post-implantation, indicating a rapid osteosynthesis process over 3weeks. The extraction torque of coated AZ31B increased with implantation time, and was higher than that of PLLA after 4weeks of implantation, equalling that of Ti6Al4V at 12weeks and was higher at 21weeks. The bending loads of non-coated AZ31B and PLLA screws degraded sharply after implantation, and that of coated AZ31B degraded more slowly. The biodegradation mechanism, the coating to control the degradation rate and the bioactivity of magnesium alloys influencing the mechanical properties loss over time and bone-implant interface strength are discussed in this study and it is concluded that a suitable degradation rate will result in an improvement in the mechanical performance of magnesium alloys, making them more suitable for clinical application. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Study of the properties of dialkyl thiophosphoric acids. Application to the extraction of U, in phosphoric and nitric solutions

    International Nuclear Information System (INIS)

    Benjelloun, N.

    1983-09-01

    A study is made of complex formation and liquid-liquid extraction of uranium (VI) by dialkyl-thiophosphoric acids of formula (RO) 2 POSH and by the synergic mixtures: dialkylthiophosphoric acids-phosphine oxides. The aqueous phases studied consist of concentrated phosphoric acid solutions and nitric acid solutions. Several methods, including distribution coefficient measurements, U.V., visible and infrared absorption spectrophotometries and magnetic resonance, were used to study the extraction mechanisms and the structures of species formed in the organic phase. The influence of different parameters (partition of extraction agent, dimerisation, acid ligand-phosphine oxide association, extraction of inorganic acids...) on the uranium (VI) distribution coefficients enabled the constants of complex formation in the aqueous phase and extraction in the organic phase to be determined. These various properties were compared with those of dialkyl phosphoric and dithiophosphoric acids. The mechanisms established prove that sulfur donors ligands form stable complexes with UO 2 2+ ions although U(VI) is considered as a ''hard class a'' acceptor according to Ahrland's classification [fr

  11. Automatic extraction of property norm-like data from large text corpora.

    Science.gov (United States)

    Kelly, Colin; Devereux, Barry; Korhonen, Anna

    2014-01-01

    Traditional methods for deriving property-based representations of concepts from text have focused on either extracting only a subset of possible relation types, such as hyponymy/hypernymy (e.g., car is-a vehicle) or meronymy/metonymy (e.g., car has wheels), or unspecified relations (e.g., car--petrol). We propose a system for the challenging task of automatic, large-scale acquisition of unconstrained, human-like property norms from large text corpora, and discuss the theoretical implications of such a system. We employ syntactic, semantic, and encyclopedic information to guide our extraction, yielding concept-relation-feature triples (e.g., car be fast, car require petrol, car cause pollution), which approximate property-based conceptual representations. Our novel method extracts candidate triples from parsed corpora (Wikipedia and the British National Corpus) using syntactically and grammatically motivated rules, then reweights triples with a linear combination of their frequency and four statistical metrics. We assess our system output in three ways: lexical comparison with norms derived from human-generated property norm data, direct evaluation by four human judges, and a semantic distance comparison with both WordNet similarity data and human-judged concept similarity ratings. Our system offers a viable and performant method of plausible triple extraction: Our lexical comparison shows comparable performance to the current state-of-the-art, while subsequent evaluations exhibit the human-like character of our generated properties.

  12. SCREENING OF ANTIMICROBIAL PROPERTIES OF ETHANOLIC EXTRACTS FROM SOME KINDS OF RAW MATERIALS WITH QUINONEDERIVATIVES

    Directory of Open Access Journals (Sweden)

    Boyko N.N.

    2014-12-01

    Full Text Available This paper presents data on screening of antimicrobial properties of extracts from some kinds of raw materials (18 plants with hydroquinone, naphtoquinone or anthraquinone derivatives. Some technological parameters of extracts (density and concentration of extraneous substances have been determined. The most appropriate microbiological method of studying antimicrobial properties of extracts, diffusion method of “well”, has been applied; special mathematic method of comparison of antimicrobial properties of extracts vector analysis has been applied in order to study and to compare antimicrobial properties of extracts. Indexes of antimicrobial properties of extracts have been determined: a complex index of medicinal product antimicrobial activity for quantitative estimation of antimicrobial effect - A, and square of correlation coefficient - r², which demonstrates the spectrum of antimicrobial activity of the extracts (degree of similarity to the standard. The most active extracts have been selected; they have antimicrobial properties of medium strength: from the herb of chimaphila umbellata А=2.20; the fruits of rhamnus cathartica А=2.12; the root of rubia tinctorum А=2.11; the bark of frangula alnus А=2.05; the root of rumex confertus А=2.04; the leaf of pyrola rotundifolia А=2.00; and leaf of arctostaphylos uva-ursi А=2.08 (but extract from uva-ursi did not affected on 2 strains of microorganisms r²=0.64. Low levels of antimicrobial activity have been demonstrated by the extract obtained from the leaf of urtica dioica А=0.72, r²=0.34. The mean result of the complex index of antimicrobial activity for the most of extracts from plants containing quinonederivatives is A = 1.77 (on 70% vol. ethanol at a ratio of raw material : extracting agent – 1:7 wt. : vol. and may range from 0.68 to 2.85. The mean result of the correlation coefficient is r = 0.93 and may range from 0.59 to 0.99. The mean result of the concentration of

  13. Antioxidant, antimicrobial, toxicity and analgesic properties of ethanol extract of Solena amplexicaulis root

    Directory of Open Access Journals (Sweden)

    Md Golam Kabir

    2014-01-01

    Full Text Available BACKGROUND: This study was subjected to investigate different pharmacological properties of ethanol extract ofSolena amplexicaulis root. RESULTS: The extract contains flavonoid, alkaloid, saponin and steroid compounds. The extract exhibited excellent antioxidant activity in DPPH radical scavenging activity. The extract also showed potent activity in brine shrimp lethality bioassay. The LC50 value was found to 44.677 µg/ml. The extract showed better anti-bacterial activity against gram-negative bacteria. In antifungal assay, the maximum 79.31% of anti-mycotic activity was observed against Aspergillus ochraceus while minimum 44.2% against Rhizopus oryzae. MIC value ranged between 1500 - 3000 µg/ml. The extract was found moderately toxic with a 24-hr LD50 value of 81.47 mg/kg in Swiss albino mice. The degree of inhibition by the ethanolic extract of the root was found less than that of standard analgesic drug diclofenac sodium. The extract also showed moderate anti-inflammatory and antinociceptive activity and anti-diabetic property. Reducing power of the extract was comparable with standard ascorbic acid. Moderate in vitro thrombolytic activity, lipid peroxidation inhibition property, metal chelating ability and stress-protective activity was also observed. CONCLUSION: Ethanol extract of Solena amplexicaulis root can be valuable for treatment of different diseases.

  14. Properties and antioxidant action of actives cassava starch films incorporated with green tea and palm oil extracts.

    Directory of Open Access Journals (Sweden)

    Kátya Karine Nery Carneiro Lins Perazzo

    Full Text Available There is an interest in the development of an antioxidant packaging fully biodegradable to increase the shelf life of food products. An active film from cassava starch bio-based, incorporated with aqueous green tea extract and oil palm colorant was developed packaging. The effects of additives on the film properties were determined by measuring mechanical, barrier and thermal properties using a response surface methodology design experiment. The bio-based films were used to pack butter (maintained for 45 days under accelerated oxidation conditions. The antioxidant action of the active films was evaluated by analyzing the peroxide index, total carotenoids, and total polyphenol. The same analysis also evaluated unpacked butter, packed in films without additives and butter packed in LDPE films, as controls. The results suggested that incorporation of the antioxidants extracts tensile strength and water vapor barrier properties (15 times lower compared to control without additives. A lower peroxide index (231.57%, which was significantly different from that of the control (p<0.05, was detected in products packed in film formulations containing average concentration of green tea extracts and high concentration of colorant. However, it was found that the high content of polyphenols in green tea extract can be acted as a pro-oxidant agent, which suggests that the use of high concentration should be avoided as additives for films. These results support the applicability of a green tea extract and oil palm carotenoics colorant in starch films totally biodegradable and the use of these materials in active packaging of the fatty products.

  15. Physico-mechanical properties of plywood bonded with ecological adhesives from Acacia mollissima tannins and lignosulfonates

    Science.gov (United States)

    Rhazi, Naima; Oumam, Mina; Sesbou, Abdessadek; Hannache, Hassan; Charrier-El Bouhtoury, Fatima

    2017-06-01

    The objective of this research was to develop ecological adhesives for bonding plywood panels using lignosulfonates, a common waste product of the wood pulp industry, and natural tannin extracted from Moroccan bark of Acacia mollissima using different process. Natural tannin and lignin were used in wood adhesives formulation to substitute resins based on phenol and formaldehyde. To achieve this, the lignosulfonates were glyoxalated to enhance their reactivity and the used tannins obtained by three different extraction methods were compared with commercial mimosa tannin. The proportion of Acacia mollissima tannins and lignosulfonates, the pressing time, the pressing temperature, and the pressure used were studied to improve mechanical properties, and bonding quality of plywood panel. The properties of plywood panels produced with these adhesives were tested in accordance with normative tests. Thus, the tensile strength, and the shear strength were measured. The results showed that the performance of the plywood panels made using biobased tannin adhesives was influenced by physical conditions such as pressure, press temperature as well as by chemical conditions, such as the tannin-lignin ratio. It exhibited excellent mechanical properties comparable to commercially available phenol-formaldehyde plywood adhesives. This study showed that biobased adhesives formulations presented good and higher mechanical performance and no formaldehyde emission. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  16. Task-specific thioglycolate ionic liquids for heavy metal extraction: Synthesis, extraction efficacies and recycling properties

    Energy Technology Data Exchange (ETDEWEB)

    Platzer, Sonja [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Kar, Mega [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Leyma, Raphlin; Chib, Sonia; Roller, Alexander [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006 Johannesburg (South Africa); Krachler, Regina [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); MacFarlane, Douglas R. [School of Chemistry, Monash University, Clayton, Victoria 3800 (Australia); Kandioller, Wolfgang, E-mail: wolfgang.kandioller@univie.ac.at [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria); Keppler, Bernhard K. [Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Str. 42, 1090 Vienna (Austria)

    2017-02-15

    Highlights: • Thioglycolate-based ionic liquids have been synthesized and their physicochemical properties have been examined. • The developed ionic liquids can efficiently remove Cu(II) and Cd(II). • Loaded ionic liquids can be recycled by application of different stripping protocols. - Abstract: Eight novel task-specific ionic liquids (TSILs) based on the thioglycolate anion designed for heavy metal extraction have been prepared and characterized by {sup 1}H and {sup 13}C NMR, UV-Vis, infrared, ESI-MS, conductivity, viscosity, density and thermal properties. Evaluation of their time-resolved extraction abilities towards cadmium(II) and copper(II) in aqueous solutions have been investigated where distribution ratios up to 1200 were observed. For elucidation of the IL extraction mode, crystals were grown where Cd(II) was converted with an excess of S-butyl thioglycolate. It was found by X-ray diffraction analysis that cadmium is coordinated by five oxygen and one sulfur donor atoms provided by two thioglycolate molecules and one water molecule. Leaching behavior of the hydrophobic ionic liquids into aqueous systems was studied by TOC (total dissolved organic carbon) measurements. Additionally, the immobilization on polypropylene was elucidated and revealed slower metal extraction rates and similar leaching behavior. Finally, recovery processes for cadmium and copper after extraction were performed and recyclability was successfully proven for both metals.

  17. Fructus ligustri lucidi ethanol extract improves bone mineral density and properties through modulating calcium absorption-related gene expression in kidney and duodenum of growing rats.

    Science.gov (United States)

    Feng, Xin; Lyu, Ying; Wu, Zhenghao; Fang, Yuehui; Xu, Hao; Zhao, Pengling; Xu, Yajun; Feng, Haotian

    2014-04-01

    Optimizing peak bone mass in early life is one of key preventive strategies against osteoporosis. Fructus ligustri lucidi (FLL), the fruit of Ligustrum lucidum Ait., is a commonly prescribed herb in many kidney-tonifying traditional Chinese medicinal formulas to alleviate osteoporosis. Previously, FLL extracts have been shown to have osteoprotective effect in aged or ovariectomized rats. In the present study, we investigated the effects of FLL ethanol extract on bone mineral density (BMD) and mechanical properties in growing male rats and explored the underlying mechanisms. Male weaning Sprague-Dawley rats were randomized into four groups and orally administrated for 4 months an AIN-93G formula-based diet supplementing with different doses of FLL ethanol extract (0.40, 0.65, and 0.90 %) or vehicle control, respectively. Then calcium balance, serum level of Ca, P, 25(OH)2D3, 1,25(OH)2D3, osteocalcin (OCN), C-terminal telopeptide of type I collagen (CTX-I), and parathyroid hormone, bone microarchitecture, and calcium absorption-related genes expression in duodenum and kidney were analyzed. The results demonstrated that FLL ethanol extract increased BMD of growing rats and improved their bone microarchitecture and mechanical properties. FLL ethanol extract altered bone turnover, as evidenced by increasing a bone formation maker, OCN, and decreasing a bone resorption maker, CTX-I. Intriguingly, both Ca absorption and Ca retention rate were elevated by FLL ethanol extract treatment, possibly through the mechanisms of up-regulating the transcriptions of calcitropic genes in kidney (1α-hydroxylase) and duodenum (vitamin D receptor, calcium transporter calbindin-D9k, and transient receptor potential vanilloid 6). In conclusion, FLL ethanol extract increased bone mass gain and improved bone properties via modulating bone turnover and up-regulating calcium absorption-related gene expression in kidney and duodenum, which could then activate 1,25(OH)2D3-dependent calcium

  18. Chronic alcohol abuse in men alters bone mechanical properties by affecting both tissue mechanical properties and microarchitectural parameters.

    Science.gov (United States)

    Cruel, M; Granke, M; Bosser, C; Audran, M; Hoc, T

    2017-06-01

    Alcohol-induced secondary osteoporosis in men has been characterized by higher fracture prevalence and a modification of bone microarchitecture. Chronic alcohol consumption impairs bone cell activity and results in an increased fragility. A few studies highlighted effects of heavy alcohol consumption on some microarchitectural parameters of trabecular bone. But to date and to our knowledge, micro- and macro-mechanical properties of bone of alcoholic subjects have not been investigated. In the present study, mechanical properties and microarchitecture of trabecular bone samples from the iliac crest of alcoholic male patients (n=15) were analyzed and compared to a control group (n=8). Nanoindentation tests were performed to determine the tissue's micromechanical properties, micro-computed tomography was used to measure microarchitectural parameters, and numerical simulations provided the apparent mechanical properties of the samples. Compared to controls, bone tissue from alcoholic patients exhibited an increase of micromechanical properties at tissue scale, a significant decrease of apparent mechanical properties at sample scale, and significant changes in several microarchitectural parameters. In particular, a crucial role of structure model index (SMI) on mechanical properties was identified. 3D microarchitectural parameters are at least as important as bone volume fraction to predict bone fracture risk in the case of alcoholic patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Scattering Mechanism Extraction by a Modified Cloude-Pottier Decomposition for Dual Polarization SAR

    Directory of Open Access Journals (Sweden)

    Kefeng Ji

    2015-06-01

    Full Text Available Dual polarization is a typical operational mode of polarimetric synthetic aperture radar (SAR. However, few studies have considered the scattering mechanism extraction of dual-polarization SARs. A modified Cloude-Pottier decomposition is proposed to investigate the performance of the scattering mechanism extraction of dual-polarization SARs. It is theoretically demonstrated that only HH-VV SAR can discriminate the three canonical scattering mechanisms from an isotropic surface, horizontal dipole, and isotropic dihedral. Various experiments are conducted using 21 scenes from real datasets acquired by AIRSAR, Convair-580 SAR, EMISAR, E-SAR, Pi-SAR, and RADARSAT-2. Division of the dual-polarization H-α plane is experimentally obtained. The lack of cross-polarization induces the diffusion of scattering mechanisms and their overlap in the HH-VV H-α plane. However, the performance of HH-VV SAR for extracting scattering mechanisms is acceptable. Thus, HH-VV SAR is a suitable alternative to full-polarization SAR in certain cases. Meanwhile, the extraction performance of the other two dual-polarization SARs is badly degraded due to the lack of co-polarization. Therefore, HH-HV and HV-VV SARs cannot effectively extract the scattering mechanisms in the H-α plane.

  20. Real-time observations of mechanical stimulus-induced enhancements of mechanical properties in osteoblast cells

    International Nuclear Information System (INIS)

    Zhang Xu; Liu Xiaoli; Sun Jialun; He Shuojie; Lee, Imshik; Pak, Hyuk Kyu

    2008-01-01

    Osteoblast, playing a key role in the pathophysiology of osteoporosis, is one of the mechanical stress sensitive cells. The effects of mechanical load-induced changes of mechanical properties in osteoblast cells were studied at real-time. Osteoblasts obtained from young Wister rats were exposed to mechanical loads in different frequencies and resting intervals generated by atomic force microscopy (AFM) probe tip and simultaneously measured the changes of the mechanical properties by AFM. The enhancement of the mechanical properties was observed and quantified by the increment of the apparent Young's modulus, E * . The observed mechanical property depended on the frequency of applied tapping loads. For the resting interval is 50 s, the mechanical load-induced enhancement of E * -values disappears. It seems that the enhanced mechanical property was recover able under no additional mechanical stimulus

  1. Peptide-Graphene Interactions Enhance the Mechanical Properties of Silk Fibroin.

    Science.gov (United States)

    Cheng, Yuan; Koh, Leng-Duei; Li, Dechang; Ji, Baohua; Zhang, Yingyan; Yeo, Jingjie; Guan, Guijian; Han, Ming-Yong; Zhang, Yong-Wei

    2015-10-07

    Studies reveal that biomolecules can form intriguing molecular structures with fascinating functionalities upon interaction with graphene. Then, interesting questions arise. How does silk fibroin interact with graphene? Does such interaction lead to an enhancement in its mechanical properties? In this study, using large-scale molecular dynamics simulations, we first examine the interaction of graphene with several typical peptide structures of silk fibroin extracted from different domains of silk fibroin, including pure amorphous (P1), pure crystalline (P2), a segment from N-terminal (P3), and a combined amorphous and crystalline segment (P4), aiming to reveal their structural modifications. Our study shows that graphene can have intriguing influences on the structures formed by the peptides with sequences representing different domains of silk fibroin. In general, for protein domains with stable structure and strong intramolecular interaction (e.g., β-sheets), graphene tends to compete with the intramolecular interactions and thus weaken the interchain interaction and reduce the contents of β-sheets. For the silk domains with random or less ordered secondary structures and weak intramolecular interactions, graphene tends to enhance the stability of peptide structures; in particular, it increases the contents of helical structures. Thereafter, tensile simulations were further performed on the representative peptides to investigate how such structure modifications affect their mechanical properties. It was found that the strength and resilience of the peptides are enhanced through their interaction with graphene. The present work reveals interesting insights into the interactions between silk peptides and graphene, and contributes in the efforts to enhance the mechanical properties of silk fibroin.

  2. Anti-Cancer Properties of Diethylether Extract of Wood from Sukun ...

    African Journals Online (AJOL)

    Purpose: To evaluate the anti-cancer properties of the diethylether extract of Sukun (Artocarpus altilis) wood. Methods: The extract was tested in human T47D breast cancer cells and examined for its effect on cell viability, nuclear morphology and sub-G1 formation. Cell viability was determined by microculture tetrazolium ...

  3. Properties and Antioxidant Action of Actives Cassava Starch Films Incorporated with Green Tea and Palm Oil Extracts

    Science.gov (United States)

    Perazzo, Kátya Karine Nery Carneiro Lins; Conceição, Anderson Carlos de Vasconcelos; dos Santos, Juliana Caribé Pires; Assis, Denilson de Jesus; Souza, Carolina Oliveira; Druzian, Janice Izabel

    2014-01-01

    There is an interest in the development of an antioxidant packaging fully biodegradable to increase the shelf life of food products. An active film from cassava starch bio-based, incorporated with aqueous green tea extract and oil palm colorant was developed packaging. The effects of additives on the film properties were determined by measuring mechanical, barrier and thermal properties using a response surface methodology design experiment. The bio-based films were used to pack butter (maintained for 45 days) under accelerated oxidation conditions. The antioxidant action of the active films was evaluated by analyzing the peroxide index, total carotenoids, and total polyphenol. The same analysis also evaluated unpacked butter, packed in films without additives and butter packed in LDPE films, as controls. The results suggested that incorporation of the antioxidants extracts tensile strength and water vapor barrier properties (15 times lower) compared to control without additives. A lower peroxide index (231.57%), which was significantly different from that of the control (pstarch films totally biodegradable and the use of these materials in active packaging of the fatty products. PMID:25251437

  4. Antibacterial Activities and Mechanism of Action of Acetone Extracts from Rabdosia rubescens

    Directory of Open Access Journals (Sweden)

    Li Ping Cheng

    2014-12-01

    Full Text Available The antibacterial activities and mechanism of action of acetone extracts from R. rubescens were reported in this paper. The results showed that 80% acetone extracts had both the highest contents of total phenolics and flavonoids. Acetone extracts showed better antibacterial activities against Gram-positive bacterial strains and there were no inhibitory effects found on tested Gram-negative bacteria. In addition, 80% acetone extracts from R. rubescens had relatively higher antibacterial activities with the lowest values of MIC and MBC at 2.5 mg/mL and 5 mg/mL against B. subtilis. The antibacterial mechanism of 80% acetone extracts against Bacillus subtilis might be described as disrupting cell wall, increasing cell membrane permeability, and finally leading to the leakage of cell constituents

  5. Selected mechanical properties of modified beech wood

    Directory of Open Access Journals (Sweden)

    Jiří Holan

    2008-01-01

    Full Text Available This thesis deals with an examination of mechanical properties of ammonia treated beach wood with a trademark Lignamon. For determination mechanical properties were used procedures especially based on ČSN. From the results is noticeable increased density of wood by 22% in comparison with untreated beach wood, which makes considerable increase of the most mechanical wood properties. Considering failure strength was raised by 32% and modulus of elasticity was raised at average about 46%.

  6. Analgesic properties of Capraria biflora leaves aqueous extract.

    Science.gov (United States)

    Acosta, S L; Muro, L V; Sacerio, A L; Peña, A R; Okwei, S N

    2003-12-01

    The analgesic properties of dried leaves of Capraria biflora were investigated. The aqueous extract (50-200 mg kg(-1)) produced moderate inhibition of acetic acid-induced writhing in mice. At the same doses, a better analgesic effect was observed on the hot plate test.

  7. Various Extraction Methods Influence the Adhesive Properties of Dried Distiller’s Grains and Solubles, and Press Cakes of Pennycress (Thlaspi arvense L. and Lesquerella [Lesquerella fendleri (A. Gary S. Watson], in the Fabrication of Lignocellulosic Composites

    Directory of Open Access Journals (Sweden)

    Brent Tisserat

    2018-04-01

    Full Text Available Lignocellulosic composite (LC panels were fabricated using an adhesive matrix prepared from three different agricultural by-products: dried distillers grains with solubles (DDGS, pennycress (Thlaspi arvense L. press cake (PPC, or lesquerella [Lesquerella fendleri (A. Gary S. Watson] press cake (LPC reinforced with Paulownia elongata L. wood (PW particles. The goal in this study was to assess the mechanical properties of composites utilizing these low-cost matrix materials, which were subjected to various oil extraction methods. Three types of oil extraction methods were utilized: ethanol, supercritical CO2, and hexane, in order to generate matrix materials. These matrix materials were mixed with equal proportions of PW and hot pressed to generate panels. Overall, hexane extraction was the best method to enhance the mechanical properties of the matrices used to fabricate lignocellulosic composites. LPC’s produced a matrix that gave the resulting composite superior flexural properties compared to composites generated from DDGS and PPC matrices. The mechanical properties of composites generated from soy products (soybean meal flour or soy protein isolate were similar to those derived from DDGS, PPC, or LPC. The dimensional stability properties of LCs were improved when the hexane extraction method was employed, unlike with the other extraction methods that were used to generate matrices.

  8. Microstructures and mechanical properties of aging materials

    International Nuclear Information System (INIS)

    Liaw, P.K.; Viswanathan, R.; Murty, K.L.; Simonen, E.P.; Frear, D.

    1993-01-01

    This book contains a collection of papers presented at the symposium on ''Microstructures and Mechanical Properties of Aging Materials,'' that was held in Chicago, IL. November 2-5, 1992 in conjunction with the Fall Meeting of The Minerals, Metals and Materials Society (TMS). The subjects of interest in the symposium included: (1) mechanisms of microstructural degradation, (2) effects of microstructural degradation on mechanical behavior, (3) development of life prediction methodology for in-service structural and electronic components, (4) experimental techniques to monitor degradation of microstructures and mechanical properties, and (5) effects of environment on microstructural degradation and mechanical properties. Individual papers have been processed separately for inclusion in the appropriate data bases

  9. Comparative study of the chemical properties of palm oil extracted ...

    African Journals Online (AJOL)

    The chemical properties of oil samples determined were free fatty acid, acid value, saponification value, peroxide value, iodine value and moisture content. The experimental design adopted was 3 x 2 x 2 factorial randomized complete block design in three replicates. The data of chemical properties of extracted palm oil ...

  10. On the mechanical properties of tooth enamel under spherical indentation.

    Science.gov (United States)

    Chai, Herzl

    2014-11-01

    The mechanical properties of tooth enamel generally exhibit large variations, which reflect its structural and material complexity. Some key properties were evaluated under localized contact, simulating actual functioning conditions. Prominent cusps of extracted human molar teeth were polished down ~0.7 mm below the cusp tip and indented by tungsten carbide balls. The internal damage was assessed after unloading from longitudinal or transverse sections. The ultimate tensile stress (UTS) was determined using a novel bilayer specimen. The damage is characterized by penny-like radial cracks driven by hoop stresses and cylindrical cracks driven along protein-rich interrod materials by shear stresses. Shallow cone cracks typical of homogeneous materials which may cause rapid tooth wear under repeat contact are thus avoided. The mean stress vs. indentation strain curve is highly nonlinear, attributable to plastic shearing of protein between and within enamel rods. This curve is also affected by damage, especially radial cracks, the onset of which depends on ball radius. Several material properties were extracted from the tests, including shear strain at the onset of ring cracks γ(F) (=0.14), UTS (=119 MPa), toughness K(C) (=0.94 MPa m(1/2)), a crack propagation law and a constitutive response determined by trial and error with the aid of a finite-element analysis. These quantities, which are only slightly sensitive to anatomical location within the enamel region tested, facilitate a quantitative assessment of crown failure. Causes for variations in published UTS and K(C) values are discussed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Mechanical Properties of Composite Materials

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Okayasu

    2014-10-01

    Full Text Available An examination has been made of the mechanical and failure properties of several composite materials, such as a short and a long carbon fiber reinforced plastic (short- and long-CFRP and metal based composite material. The short CFRP materials were used for a recycled CFRP which fabricated by the following process: the CFRP, consisting of epoxy resin with carbon fiber, is injected to a rectangular plate cavity after mixing with acrylonitrile butadiene styrene resin with different weight fractions of CFRP. The fatigue and ultimate tensile strength (UTS increased with increasing CFRP content. These correlations, however, break down, especially for tensile strength, as the CFPR content becomes more than 70%. Influence of sample temperature on the bending strength of the long-CFRP was investigated, and it appears that the strength slightly degreases with increasing the temperature, due to the weakness in the matrix. Broken fiber and pull-out or debonding between the fiber and matrix were related to the main failure of the short- and long-CFRP samples. Mechanical properties of metal based composite materials have been also investigated, where fiber-like high hardness CuAl2 structure is formed in aluminum matrix. Excellent mechanical properties were obtained in this alloy, e.g., the higher strength and the higher ductility, compared tothe same alloy without the fiber-like structure. There are strong anisotropic effects on the mechanical properties due to the fiber-like metal composite in a soft Al based matrix.

  12. Effects and Mechanism of Action of a Tribulus terrestris Extract on Penile Erection

    Science.gov (United States)

    Do, Jungmo; Choi, Seemin; Choi, Jaehwi

    2013-01-01

    Purpose Tribulus terrestris has been used as an aphrodisiac. However, little is known about the effects and mechanism of action of T. terrestris on penile erection. Therefore, the effect of a T. terrestris extract and the mechanism of action of the extract on relaxation of the corpus cavernosum (CC) were investigated. The erectogenic effects of an oral preparation of the extract were also assessed. Materials and Methods The relaxation effects and mechanism of action of the T. terrestris extract on rabbit CC were investigated in an organ bath. The intracavernous pressure (ICP) was calculated after oral administration of the extract for 1 month to evaluate whether the relaxation response of the CC shown in the organ bath occurred in vivo. Additionally, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured in the CC by immunoassay. Smooth muscle relaxation was expressed as the percentage decrease in precontraction induced by phenylephrine. The ICP was also assessed in rats after oral administration of the extract for 1 month, and changes in concentrations of cGMP and cAMP were monitored. Results Concentration-dependent relaxation effects of the extract on the CC were detected in the organ bath study. Relaxation of the CC by the T. terrestris extract was inhibited in both an endothelium-removed group and an L-arginen methyl ester pretreatment group. The ICP measured after oral administration of the T. terrestris extract for 1 month was higher than that measured in the control group, and a significant increase in cAMP was observed in the T. terrestris extract group. Conclusions The T. terrestris extract induced concentration-dependent relaxation of the CC in an organ bath. The mechanism included a reaction involving the nitric oxide/nitric oxide synthase pathway and endothelium of the CC. Moreover, in an in vivo study, the T. terrestris extract showed a significant concentration-dependent increase in ICP. Accordingly, the T

  13. Effects and Mechanism of Action of a Tribulus terrestris Extract on Penile Erection.

    Science.gov (United States)

    Do, Jungmo; Choi, Seemin; Choi, Jaehwi; Hyun, Jae Seog

    2013-03-01

    Tribulus terrestris has been used as an aphrodisiac. However, little is known about the effects and mechanism of action of T. terrestris on penile erection. Therefore, the effect of a T. terrestris extract and the mechanism of action of the extract on relaxation of the corpus cavernosum (CC) were investigated. The erectogenic effects of an oral preparation of the extract were also assessed. The relaxation effects and mechanism of action of the T. terrestris extract on rabbit CC were investigated in an organ bath. The intracavernous pressure (ICP) was calculated after oral administration of the extract for 1 month to evaluate whether the relaxation response of the CC shown in the organ bath occurred in vivo. Additionally, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured in the CC by immunoassay. Smooth muscle relaxation was expressed as the percentage decrease in precontraction induced by phenylephrine. The ICP was also assessed in rats after oral administration of the extract for 1 month, and changes in concentrations of cGMP and cAMP were monitored. Concentration-dependent relaxation effects of the extract on the CC were detected in the organ bath study. Relaxation of the CC by the T. terrestris extract was inhibited in both an endothelium-removed group and an L-arginen methyl ester pretreatment group. The ICP measured after oral administration of the T. terrestris extract for 1 month was higher than that measured in the control group, and a significant increase in cAMP was observed in the T. terrestris extract group. The T. terrestris extract induced concentration-dependent relaxation of the CC in an organ bath. The mechanism included a reaction involving the nitric oxide/nitric oxide synthase pathway and endothelium of the CC. Moreover, in an in vivo study, the T. terrestris extract showed a significant concentration-dependent increase in ICP. Accordingly, the T. terrestris extract may improve erectile function.

  14. Chilean berry Ugni molinae Turcz. fruit and leaves extracts with interesting antioxidant, antimicrobial and tyrosinase inhibitory properties.

    Science.gov (United States)

    López de Dicastillo, Carol; Bustos, Fernanda; Valenzuela, Ximena; López-Carballo, Gracia; Vilariño, Jose M; Galotto, Maria Jose

    2017-12-01

    The knowledge of the biological properties of fruits and leaves of murta (Ugni molinae Turcz.) has been owned by native Chilean culture. The present study investigated the phenolic content, the antioxidant, antimicrobial and anti-tyrosinase activities of different murta fruit and leaves extracts to approach their uses on future food, pharmaceutical and cosmetic applications. Extractions of murta fruit and leaves were carried out under water, ethanol and ethanol 50%. Phenolic content of these extracts was measured through Folin Ciocalteu test and the antioxidant power by four different antioxidant systems (ORAC, FRAP, DPPH and TEAC assays) owing to elucidate the main mechanism of antioxidant. Some flavonoids, such as rutin, isoquercitrin and quercitrin hydrate were identified and quantified through HPLC analysis. Antimicrobial activity was determined measuring minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) values against Escherichia coli and Listeria monocytogenes, and the effect of these extracts on L. monocytogenes was confirmed by flow cytometry. Highest contents of polyphenol compounds were obtained in hydroalcoholic extracts (28±1mggallicacid/g dry fruit, and 128±6mggallicacid/g dry leaves). The same trend was found for the values of biological properties: hydroalcoholic extracts showed the strongest activities. Leaves presented higher antioxidant, antimicrobial and anti-tyrosinase properties than murta fruit. Highest antioxidant activity values according to ORAC, FRAP, TEAC and DPPH were 80±8mgTrolox/g, 70±2mgTrolox/g, 87±8mgTrolox/g and 110±12mgTrolox/g, respectively, for murta fruit samples, and 280±10mgTrolox/g, 192±4mgTrolox/g, 286±13mgTrolox/g and 361±13mgTrolox/g, respectively, for murta leaves. These activities were confirmed by HPLC analysis that revealed highest presence of analyzed compounds on leaves hydroalcoholic extract. Regarding to antimicrobial analysis, hydroalcoholic leaves extract presented the

  15. Microstructure, local and global mechanical properties of friction stir welds in aluminium alloy 6005A-T6

    International Nuclear Information System (INIS)

    Simar, A.; Brechet, Y.; Meester, B. de; Denquin, A.; Pardoen, T.

    2008-01-01

    The effect of the welding speed on the microstructure, local and overall mechanical properties of friction stir welded joints has been investigated in the aluminium alloy 6005A-T6. The fine hardening precipitation within the heat-affected zone has been characterized by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Post-welding heat treatments have been applied to obtain indications on the level of solid solution supersaturation in the as welded state. The local mechanical behaviour was determined using thin specimens extracted from various regions of the weld. The overall properties were measured on samples cut perpendicular to the weld. Specific attention was devoted to the relationship between the local microstructure and local hardening properties in the weakest region, which govern the overall strength and ductility of the welds

  16. Study of anisotropic mechanical properties for aeronautical PMMA

    Directory of Open Access Journals (Sweden)

    Wei Shang

    Full Text Available For the properties of polymer are relative to its structure, the main purpose of the present work is to investigate the mechanical properties of the aeronautical PMMA which has been treated by the directional tensile technology. Isodyne images reveal the stress state in directional PMMA. And then, an anisotropic mechanical model is established. Furthermore, all mechanical parameters are measured by the digital image correlation method. Finally, based on the anisotropic mechanical model and mechanical parameters, the FEM numerical simulation and experimental methods are applied to analyze the fracture mechanical properties along different directions.

  17. Mechanical properties of hydroxyapatite single crystals from nanoindentation data

    Science.gov (United States)

    Zamiri, A.; De, S.

    2011-01-01

    In this paper we compute elasto-plastic properties of hydroxyapatite single crystals from nanindentation data using a two-step algorithm. In the first step the yield stress is obtained using hardness and Young’s modulus data, followed by the computation of the flow parameters. The computational approach is first validated with data from existing literature. It is observed that hydroxyapatite single crystals exhibit anisotropic mechanical response with a lower yield stress along the [1010] crystallographic direction compared to the [0001] direction. Both work hardening rate and work hardening exponent are found to be higher for indentation along the [0001] crystallographic direction. The stress-strain curves extracted here could be used for developing constitutive models for hydroxyapatite single crystals. PMID:21262492

  18. Performance of a demand controlled mechanical extract ventilation system for dwellings

    Directory of Open Access Journals (Sweden)

    I. Pollet

    2013-10-01

    Full Text Available The main aim of ventilation is to guarantee a good indoor air quality, related to the energy consumed for heating and fan(s. Active or passive heat recovery systems seem to focus on the reduction of heating consumption at the expense of fan electricity consumption and maintenance. In this study, demandcontrolled mechanical extract ventilation systems of Renson (DCV1 and DCV2, based on natural supply in the habitable rooms and mechanical extraction in the wet rooms (or even the bedrooms, was analysed for one year by means of multi-zone Contam simulations on a reference detached house and compared with standard MEV and mechanical extract ventilation systems with heat recovery (MVHR. To this end, IAQ, total energy consumption, CO2 emissions and total cost of the systems are determined. The results show that DCV systems with increased supply air flow rates or direct mechanical extract from bedrooms can significantly improve IAQ, while reducing total energy consumption compared to MEV. Applying DCV reduces primary heating energy consumption and yearly fan electricity consumption at most by 65% to 50% compared to MEV. Total operational energy costs and CO2 emissions of DCV are similar when compared to MVHR. Total costs of DCV systems over 15 years are smaller when compared to MVHR due to lower investment and maintenance costs.

  19. Antimicrobial properties of coconut husk aqueous extract on cariogenic bacteria

    Directory of Open Access Journals (Sweden)

    Maria B Cyriac

    2013-01-01

    Full Text Available Background and Objectives: The husk fibers of coconut (Cocos nucifera are reported to be used by people of rural areas of South India for daily cleaning their teeth. As the beneficial effects of this plant material, with respect to antimicrobial properties against common cariogenic bacteria, are not scientifically proven, the present study was conducted. Materials and Methods: The husk of coconut was collected and aqueous extract was prepared and antimicrobial properties against common oral pathogens like Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, and Lactobacillus acidophilus were performed by agar well diffusion method. The values obtained were then subjected to statistical analysis using one way ANOVA and Tukey HSD. Results: Aqueous extract of coconut husk showed a concentration-dependent antimicrobial activity against different tested organisms with zone of inhibition ranging from 4.44 to 15.33 mms. However, the efficacy was less in comparison to chlorhexidine. Conclusion: Inhibitory action against cariogenic bacteria exhibited by aqueous extract of coconut husk indicate presence of highly effective active compounds in these extracts, which can be identified and incorporated into modern oral care systems for controlling dental caries.

  20. ANTIMICROBIAL PROPERTIES OF PLEUROTUS ERYNGII AND LENTINUS EDODES HYDRO-ALCOHOLIC EXTRACTS

    Directory of Open Access Journals (Sweden)

    Gabriela Popa

    2016-11-01

    Full Text Available Besides superior nutritional values mushrooms posed significant medicinal properties. Hydro-alcoholic extracts of several isolates of Pleurotus eryngii and Lentinus edodes mushroom species were investigated for their antimicrobial activities against pathogenic microorganisms with medicinal importance. Antimicrobial activities of the extracts were evaluated by the agar disk diffusion method. Results revealed that the 70% ethylic alcohol extracts have significant inhibitory activities against Bacillus subtilis var. spizizinii, Escherichia coli and Staphylococcus aureus. The results showed that the 70% ethanol extracts of Pleurotus eryngii and Lentinus edodes mushroom isolates may have biopharmaceutical potentiality.

  1. Mechanism of antagonistic effects of Andrographis paniculata methanolic extract against Staphylococcus aureus.

    Science.gov (United States)

    Hussain, Roslinah Mohamad; Razak, Zayan Nabilah Rasyidah Abd; Saad, Wan Mazlina Md; Mustakim, Maimunah

    2017-07-01

    To investigate the effects of Andrographis paniculata (Burm.f.) Wall. Ex Nees (A. paniculata) on expressions and activities of catalase, superoxide dismutase and alkylhydroperoxide reductase C in Staphylococcus aureus (S. aureus) with respect to its survival in vitro. Antioxidative property of methanolic leaves extract of A. paniculata (0.06 mg/mL). Minimum inhibitory concentration (MIC) was determined by its ability to reduce hydrogen peroxide (H 2 O 2 ) toxicity against S. aureus ATCC 25923 [(3.8 × 10 8 ) cfu/mL]. Effects of the extract on expressions of katA (encoding catalase), sodA and sodM [encoding superoxide dismutases (SODs)], and ahpC [encoding alkylhydroperoxide reductase C (AhpC)] in S. aureus were determined by RT-qPCR and corresponding enzyme activity assays were performed. Nitroblue tetrazolium reduction (NBT) assay was performed to determine effects of the extract on intracellular and extracellular levels of O 2- in S. aureus. Cells challenged with 7.5 mmol/L H 2 O 2 showed 0% survival in 30 min whereas 25% survived after treatment with the extract and H 2 O 2 . Cells that were treated with the extract alone had 43% survival in the same exposure period. Expressions of sodA and sodM genes in extract-treated cells were lowered 0.8-fold and 0.7-fold, respectively with decrease in total SOD activity of 26.8 U compared to untreated cells, 32.4 U (P paniculata methanolic leaves extract (0.06 mg/mL) reduce H 2 O 2 toxicity and more importantly, was in itself effectively inhibitory against S. aureus. Further, our observations suggest that a probable mode of its inhibitory mechanism against S. aureus is by reducing total SOD activity through downregulation of sodA and sodM expressions. Copyright © 2017 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

  2. Mechanical Properties of Organic Semiconductors for Stretchable, Highly Flexible, and Mechanically Robust Electronics.

    Science.gov (United States)

    Root, Samuel E; Savagatrup, Suchol; Printz, Adam D; Rodriquez, Daniel; Lipomi, Darren J

    2017-05-10

    Mechanical deformability underpins many of the advantages of organic semiconductors. The mechanical properties of these materials are, however, diverse, and the molecular characteristics that permit charge transport can render the materials stiff and brittle. This review is a comprehensive description of the molecular and morphological parameters that govern the mechanical properties of organic semiconductors. Particular attention is paid to ways in which mechanical deformability and electronic performance can coexist. The review begins with a discussion of flexible and stretchable devices of all types, and in particular the unique characteristics of organic semiconductors. It then discusses the mechanical properties most relevant to deformable devices. In particular, it describes how low modulus, good adhesion, and absolute extensibility prior to fracture enable robust performance, along with mechanical "imperceptibility" if worn on the skin. A description of techniques of metrology precedes a discussion of the mechanical properties of three classes of organic semiconductors: π-conjugated polymers, small molecules, and composites. The discussion of each class of materials focuses on molecular structure and how this structure (and postdeposition processing) influences the solid-state packing structure and thus the mechanical properties. The review concludes with applications of organic semiconductor devices in which every component is intrinsically stretchable or highly flexible.

  3. Investigation of the Antiasthmatic Properties of Ethanol Extract of ...

    African Journals Online (AJOL)

    Investigation of the Antiasthmatic Properties of Ethanol Extract of Callophyllis japonica in Mice. WS Park, KS Lee, JH Chun, SH Urm, DS Lee, DY Lee, SG Park, SK Seo, SJ Heo, ZJ Qian, WK Jung, IW Choi ...

  4. Stochastic modelling in design of mechanical properties of nanometals

    International Nuclear Information System (INIS)

    Tengen, T.B.; Wejrzanowski, T.; Iwankiewicz, R.; Kurzydlowski, K.J.

    2010-01-01

    Polycrystalline nanometals are being fabricated through different processing routes and conditions. The consequence is that nanometals having the same mean grain size may have different grain size dispersion and, hence, may have different material properties. This has often led to conflicting reports from both theoretical and experimental findings about the evolutions of the mechanical properties of nanomaterials. The present paper employs stochastic model to study the impact of microstructure evolution during grain growth on the mechanical properties of polycrystalline nanometals. The stochastic model for grain growth and the stochastic model for changes in mechanical properties of nanomaterials are proposed. The model for the mechanical properties developed is tested on aluminium samples.Many salient features of the mechanical properties of the aluminium samples are revealed. The results show that the different mechanisms of grain growth impart different nature of response to the material mechanical properties. The conventional, homologous and anomalous temperature dependences of the yield stress have also been revealed to be due to different nature of interactions of the microstructures during evolution.

  5. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti-Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti-Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti-Ag phase, residual pure Ag and Ti were the mainly phases in Ti-Ag(S75) sintered alloy while Ti2Ag was synthesized in Ti-Ag(S10) sintered alloy. The mechanical test indicated that Ti-Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti-Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti-Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Mechanical properties of ordered alloys

    International Nuclear Information System (INIS)

    Kroupa, F.

    1977-06-01

    A survey is given of the metallophysical fundamentals of the mechanical properties of ordered two-phase alloys. Alloys of this type have a superlattice structure in a substitution mixed crystal. Ordering is achieved by slow cooling or by annealing below the critical temperature, during which ordering domains (antiphase domains) are formed. At a high degree of ordering, the dislocations are concentrated to form pairs, so-called super-dislocations. The mechanical properties may be selectively changed by varying different parameters (size of the ordering domains, degree of ordering, energy of the antiphase boundaries) by a special composition and heat treatment.(GSC) [de

  7. Skin mechanical properties and modeling: A review.

    Science.gov (United States)

    Joodaki, Hamed; Panzer, Matthew B

    2018-04-01

    The mechanical properties of the skin are important for various applications. Numerous tests have been conducted to characterize the mechanical behavior of this tissue, and this article presents a review on different experimental methods used. A discussion on the general mechanical behavior of the skin, including nonlinearity, viscoelasticity, anisotropy, loading history dependency, failure properties, and aging effects, is presented. Finally, commonly used constitutive models for simulating the mechanical response of skin are discussed in the context of representing the empirically observed behavior.

  8. Mechanical properties of chemically modified portuguese pinewood

    OpenAIRE

    Lopes, Duarte B; Mai, Carsten; Militz, Holger

    2014-01-01

    To turn wood into a construction material with enhanced properties, many methods of chemical modification have been developed in the last few decades. In this work, mechanical properties of pine wood were chemically modified, compared and evaluated. Maritime pine wood (Pinus pinaster) was modified with four chemical processes: 1,3-dimethylol-4,5- dihydroxyethyleneurea, N-methylol melamine formaldehyde, tetra-alkoxysilane and wax. The following mechanical properties were assessed experiment...

  9. Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

    Science.gov (United States)

    Takagi, Hitoshi; Nakagaito, Antonio N.; Kusaka, Kazuya; Muneta, Yuya

    2015-03-01

    Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

  10. Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

    Energy Technology Data Exchange (ETDEWEB)

    Natsuki, Toshiaki [Shinshu University, Faculty of Textile Science and Technology, Ueda (Japan); Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan); Natsuki, Jun [Shinshu University, Institute of Carbon Science and Technology, Nagano (Japan)

    2017-04-15

    Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

  11. Prediction of mechanical properties for hexagonal boron nitride nanosheets using molecular mechanics model

    International Nuclear Information System (INIS)

    Natsuki, Toshiaki; Natsuki, Jun

    2017-01-01

    Mechanical behaviors of nanomaterials are not easy to be evaluated in the laboratory because of their extremely small size and difficulty controlling. Thus, a suitable model for the estimation of the mechanical properties for nanomaterials becomes very important. In this study, the elastic properties of boron nitride (BN) nanosheets, including the elastic modulus, the shear modulus, and the Poisson's ratio, are predicted using a molecular mechanics model. The molecular mechanics force filed is established to directly incorporate the Morse potential function into the constitutive model of nanostructures. According to the molecular mechanics model, the chirality effect of hexagonal BN nanosheets on the elastic modulus is investigated through a closed-form solution. The simulated result shows that BN nanosheets exhibit an isotropic elastic property. The present analysis yields a set of very simple formulas and is able to be served as a good approximation on the mechanical properties for the BN nanosheets. (orig.)

  12. Development of a Small Punch Test Technique for an Evaluation of the Mechanical Properties of Irradiated Materials in a Hot Cell

    International Nuclear Information System (INIS)

    Kim, Do-Sik; Ahn, Sang-Bok; Yoo, Byung-Ok; Choo, Yong-Sun; Hong, Kwon-Pyo

    2006-01-01

    Miniaturized specimens have been widely used to evaluate the mechanical properties of steels and plastics. Especially for a study on the irradiation effects in nuclear materials, the small specimen test techniques have attracted considerable attention. Therefore, it is essential that the test techniques be developed and verified to extract the mechanical properties information from small specimens. Among the test techniques using small specimens, the small punch (SP) test technique using small disc-sized specimen has been successfully used to estimate the tensile properties (yield strength and ultimate tensile strength), DBTT (ductile-brittle transition temperature), fracture toughness and creep properties of metals irradiated in a reactor or a proton accelerator. In this paper, the existing SP test techniques are reviewed and summarized. In addition, the information on the development of the SP test procedure is obtained to evaluate the radiation effects on the mechanical properties of nuclear materials in a hot cell

  13. ANTIOXIDANT AND ANTIMICROBIAL PROPERTIES OF STEVIA LEAVES EXTRACTS AND SILVER NANOPARTICLES COLLOIDS

    Directory of Open Access Journals (Sweden)

    Iryna Laguta

    2016-12-01

    Full Text Available Three extracts of Stevia rebaudiana (Bertoni were prepared using various types of raw materials: leaves of plants grown ex situ, leaves of plants grown in vitro, callus culture formed on damaged leaves. Composition of the extracts, their activity in the synthesis of silver nanoparticles colloids, as well as antioxidant and antimicrobial properties of the extracts and the colloids were investigated.

  14. Immunomodulatory properties of Alternanthera tenella Colla aqueous extracts in mice

    Directory of Open Access Journals (Sweden)

    R.N.M. Guerra

    2003-09-01

    Full Text Available Plants from the genus Alternanthera are thought to possess antimicrobial and antiviral properties. In Brazilian folk medicine, the aqueous extract of A. tenella Colla is used for its anti-inflammatory activity. The present study investigated the immunomodulatory property of A. tenella extract by evaluating the antibody production in male albino Swiss mice weighing 20-25 g (10 per group. The animals received standard laboratory diet and water ad libitum. The effect of A. tenella extract (5 and 50 mg/kg, ip was evaluated in mice immunized with sheep red blood cells (SRBC 10%, ip as T-dependent antigen, or in mice stimulated with mitogens (10 µg, Escherichia coli lipopolysaccharide, LPS, ip. The same doses (5 and 50 mg/kg, ip of A. tenella extract were also tested for antitumor activity, using the Ehrlich ascites carcinoma as model. The results showed that 50 mg/kg A. tenella extract ip significantly enhanced IgM (64% and IgG2a (50% antibody production in mice treated with LPS mitogen. The same dose had no effect on IgM-specific response, whereas the 5 mg/kg treatment caused a statiscally significant reduction of anti-SRBC IgM-specific antibodies (82%. The aqueous extract of A. tenella (50 mg/kg increased the life span (from 16 ± 1 to 25 ± 1 days and decreased the number of viable tumor cells (59% in mice with Ehrlich ascites carcinoma. The present findings are significant for the development of alternative, inexpensive and perhaps even safer strategies for cancer treatment.

  15. Antitumor effects and mechanisms of Ganoderma extracts and spores oil.

    Science.gov (United States)

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-11-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC 50 ) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC 50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle.

  16. Effect of Mechanical Alloying Atmospheres and Oxygen Concentration on Mechanical Properties of ODS Ferritic Steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kim, Kibaik; Kang, Sukhoon; Chun, Youngbum; Kim, Taekyu

    2013-01-01

    Finely dispersed nano-oxide particles with a high number density in the homogeneous grain matrix are essential to achieve superior mechanical properties at high temperatures, and these unique microstructures can be obtained through the mechanical alloying (MA) and hot consolidation process. The microstructure and mechanical property of ODS steel significantly depends on its powder property and the purity after the MA process. These contents should be carefully controlled to improve the mechanical property at elevated temperature. In particular, appropriate the control of oxygen concentration improves the mechanical property of ODS steel at high temperature. An effective method is to control the mechanical alloying atmosphere by high purity inert gas. In the present study, the effects of mechanical alloying atmospheres and oxygen concentration on the mechanical property of ODS steel were investigated. ODS ferritic alloys were fabricated in various atmospheres, and the HIP process was used to investigate the effects of MA atmospheres and oxygen concentration on the microstructure and mechanical property. ODS ferritic alloys milled in an Ar-H 2 mixture, and He is effective to reduce the excess oxygen concentration. The YH 2 addition made an extremely reduced oxygen concentration by the internal oxygen reduction reaction and resulted in a homogeneous microstructure and superior creep strength

  17. Antioxidant and Antiangiogenic Properties, and Gas Chromatographic-Time of Flight Analysis of Sonchus arvensis Leaves Extracts

    International Nuclear Information System (INIS)

    Itam, A.; Shah, A. M.; Majid, A.; Ismail, Z.

    2015-01-01

    Sonchus arvensis L. (Asteraceae) is one of the medicinal herbs used in traditional medicines, in which the leaf extract was used as a diuretic, lithotriptic and antiurolithiasis agent. The leaves of S. arvensis reported contain several compounds, including a variety of flavonoids, terpenoids and sterol, even this plant also contain silica and potassium. Flavonoids are secondary metabolite compound which have ability as antioxidant. In this study, the aims are to determine of antioxidants and antiangiogenic properties, and phytoconstituents quantitative of aqueous and methanol extracts of S. arvensis leaves. The antioxidant properties were studied using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical, xanthine oxidase and beta-carotene-linoleate models system. Furthermore, the antiangiogenic property was evaluated using ex vivo rat aorta ring assay. Quantitative determination of extracts phytoconstituents were carried out by using Gas Chromatographic-Time of Flight (GC-TOF) mass spectrophotometric methods. The results showed that the aqueous and methanol extracts have ability as antioxidant which is antioxidant activities of aqueous extracts on DPPH radical and inhibition of xanthine oxidase activity are higher than that of methanol extracts. Meanwhile antioxidant activity using beta-carotene-linoleate model system of S. arvensis aqueous extract is lower than that of methanol extracts. Nevertheless, the differences of these antioxidant activities are not significant. Antiangiogenic property of aqueous extract is also higher than that of methanol extract which is measured at 100 meu g mL/sup -1/ of extracts. This indicates that there is correlation between antioxidant activity and antiangigenic property, exhibiting that this plant possesses the potential to prevent or cure the diseases that related to angiogenesis such as cancer. (author)

  18. Mechanical properties of nuclear waste glasses

    International Nuclear Information System (INIS)

    Connelly, A.J.; Hand, R.J.; Bingham, P.A.; Hyatt, N.C.

    2011-01-01

    The mechanical properties of nuclear waste glasses are important as they will determine the degree of cracking that may occur either on cooling or following a handling accident. Recent interest in the vitrification of intermediate level radioactive waste (ILW) as well as high level radioactive waste (HLW) has led to the development of new waste glass compositions that have not previously been characterised. Therefore the mechanical properties, including Young's modulus, Poisson's ratio, hardness, indentation fracture toughness and brittleness of a series of glasses designed to safely incorporate wet ILW have been investigated. The results are presented and compared with the equivalent properties of an inactive simulant of the current UK HLW glass and other nuclear waste glasses from the literature. The higher density glasses tend to have slightly lower hardness and indentation fracture toughness values and slightly higher brittleness values, however, it is shown that the variations in mechanical properties between these different glasses are limited, are well within the range of published values for nuclear waste glasses, and that the surveyed data for all radioactive waste glasses fall within relatively narrow range.

  19. Mechanical and electro-mechanical properties of three-dimensional nanoporous graphene-poly(vinylidene fluoride composites

    Directory of Open Access Journals (Sweden)

    G. P. Zheng

    2016-09-01

    Full Text Available Three-dimensional nanoporous graphene monoliths are utilized to prepare graphene-poly(vinylidene fluoride nanocomposites with enhanced mechanical and electro-mechanical properties. Pre-treatment of the polymer (poly(vinylidene fluoride, PVDF with graphene oxides (GOs facilitates the formation of uniform and thin PVDF films with a typical thickness below 100 nm well coated at the graphene nano-sheets. Besides their excellent compressibility, ductility and mechanical strength, the nanoporous graphene-PVDF nanocomposites are found to possess high sensitivity in strain-dependent electrical conductivity. The improved mechanical and electro-mechanical properties are ascribed to the enhanced crystalline β phase in PVDF which possesses piezoelectricity. The mechanical relaxation analyses on the interfaces between graphene and PVDF reveal that the improved mechanical and electro-mechanical properties could result from the interaction between the –C=O groups in the nanoporous graphene and the –CF2 groups in PVDF, which also explains the important role of GOs in the preparation of the graphene-polymer nanocomposites with superior combined mechanical and electro-mechanical properties.

  20. Biological properties of mud extracts derived from various spa resorts.

    Science.gov (United States)

    Spilioti, Eliana; Vargiami, Margarita; Letsiou, Sophia; Gardikis, Konstantinos; Sygouni, Varvara; Koutsoukos, Petros; Chinou, Ioanna; Kassi, Eva; Moutsatsou, Paraskevi

    2017-08-01

    Spa resorts are known for thousands of years for their healing properties and have been empirically used for the treatment of many inflammatory conditions. Mud is one of the most often used natural materials for preventive, healing and cosmetic reasons and although it has been used since the antiquity, little light has been shed on its physical, chemical and biological properties. In this study we examined the effect of mud extracts on the expression of adhesion molecules (CAMs) by endothelial cells as well as their effects on monocyte adhesion to activated endothelial cells. Most of mud extracts inhibited the expression of VCAM-1 by endothelial cells and reduced monocyte adhesion to activated endothelial cells, indicating a potent anti-inflammatory activity. Furthermore, the mud extracts were tested for their antimicrobial activity; however, most of them appeared inactive against S. aureus and S. epidermidis. One of the mud extracts (showing the best stabilization features) increased significantly the expression of genes involved in cell protection, longevity and hydration of human keratinocytes, such as, collagen 6A1, forkhead box O3, sirtuin-1, superoxide dismutase 1 and aquaporin-3. The present study reveals that mud exerts important beneficial effects including anti-inflammatory and anti-aging activity as well as moisturizing effects, implicating important cosmeceutical applications.

  1. Change in mechanical properties of Antrim oil shale on retorting

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S. P.; Hockings, W. A.; Kim, K.

    1979-01-01

    The decomposition of kerogen in oil shale and subsequent extraction of the decomposition products during the retorting process are known to alter the pore structure, resulting in changes in permeability, deformation and strength properties. Prediction of these changes is of fundamental importance in the design of in-situ retorting processes. This paper summarizes a comprehensive laboratory investigation on the changes in mechanical properties of Antrim oil shale on retorting at 500/sup 0/C. It was observed that kerogen plays an important role in the change of the properties on retorting. When subjected to heat, the degree of deformation, the extent of fracturing and the structural instability of the specimens appeared to be strongly dependent upon kerogen content. The values of elastic modulus, strength, and density decreased whereas maximum strain at failure increased on retorting. Significant increases in permeability and porosity also resulted from retorting. The most pronounced increase was observed in the permeability in the direction parallel to bedding which exceeded in some cases as much as 3 orders of magnitude. Microscopic observations of pore structures provided a qualitative support to data obtained in measurements of porosity and permeability.

  2. A Hierarchical Feature Extraction Model for Multi-Label Mechanical Patent Classification

    Directory of Open Access Journals (Sweden)

    Jie Hu

    2018-01-01

    Full Text Available Various studies have focused on feature extraction methods for automatic patent classification in recent years. However, most of these approaches are based on the knowledge from experts in related domains. Here we propose a hierarchical feature extraction model (HFEM for multi-label mechanical patent classification, which is able to capture both local features of phrases as well as global and temporal semantics. First, a n-gram feature extractor based on convolutional neural networks (CNNs is designed to extract salient local lexical-level features. Next, a long dependency feature extraction model based on the bidirectional long–short-term memory (BiLSTM neural network model is proposed to capture sequential correlations from higher-level sequence representations. Then the HFEM algorithm and its hierarchical feature extraction architecture are detailed. We establish the training, validation and test datasets, containing 72,532, 18,133, and 2679 mechanical patent documents, respectively, and then check the performance of HFEMs. Finally, we compared the results of the proposed HFEM and three other single neural network models, namely CNN, long–short-term memory (LSTM, and BiLSTM. The experimental results indicate that our proposed HFEM outperforms the other compared models in both precision and recall.

  3. Effect of Partial Pre-Extraction of Hemicelluloses on the Properties of Pinus radiata Chemimechanical Pulps

    Directory of Open Access Journals (Sweden)

    Pablo Reyes

    2015-09-01

    Full Text Available Extraction of hemicelluloses prior to pulping and conversion of the extracted hemicelluloses to other bioproducts could provide additional revenue to traditional pulp and paper industries. The effect of hemicelluloses pre-extraction with a hydrothermal (HT process on Pinus radiata chemimechanical pulp (CMP properties was investigated in this study. The HT extraction resulted in a release of 7% to 58% of the initial amount of hemicelluloses from the wood. The extraction yield increased with temperature and extraction time. This hemicellulosic fraction was in the form of low molar mass oligomers with molecular weights varying from 1.5 to 100 kDa. Compared with the control (unextracted CMP pulp, the HT pre-extraction significantly reduced the refining energy to obtain a given fibrillation degree (freeness. The pulp yield with the HT/CMP process was in the range of 56% to 75%. Fiber properties of the pulps from pre-extracted wood, such as fiber length, were reduced, while increases in fiber width, fines content, fiber coarseness, and kink index were observed in comparison with the control pulps. The strength properties of CMP pulps decreased with increasing amounts of hemicellulose removal during the stage prior to pulping.

  4. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti–Ag sintered alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mian [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Erlin, E-mail: zhangel@atm.neu.edu.cn [Key Lab. for Anisotropy and Texture of Materials, Education Ministry of China, Northeastern University, Shenyang 110819 (China); Zhang, Lan [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti–Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti–Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti–Ag phase, residual pure Ag and Ti were the mainly phases in Ti–Ag(S75) sintered alloy while Ti{sub 2}Ag was synthesized in Ti–Ag(S10) sintered alloy. The mechanical test indicated that Ti–Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti–Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti–Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3 wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti{sub 2}Ag and its distribution. - Highlights: • Ti–Ag alloy with up to 99% antibacterial rate was developed by powder metallurgy. • The effects of the Ag powder size and the Ag content on the

  5. Variability of mechanical properties of nuclear pressure vessel steels

    International Nuclear Information System (INIS)

    Petrequin, P.; Soulat, P.

    1980-01-01

    Causes of variability of mechanical properties nuclear pressure vessel steels are reviewed and discussed. The effects of product shape and size, processing history and heat treatment are investigated. Some quantitative informations are given on the scatter of mechanical properties of typical pressure vessel components. The necessity of using recommended or standardized properties for comparing mechanical properties before and after irradiation in pin pointed. (orig.) [de

  6. Experimental Analysis of Tensile Mechanical Properties of Sprayed FRP

    Directory of Open Access Journals (Sweden)

    Zhao Yang

    2016-01-01

    Full Text Available To study the tensile mechanical properties of sprayed FRP, 13 groups of specimens were tested through uniaxial tensile experiments, being analyzed about stress-strain curve, tensile strength, elastic modulus, breaking elongation, and other mechanical properties. Influencing factors on tensile mechanical properties of sprayed FRP such as fiber type, resin type, fiber volume ratio, fiber length, and composite thickness were studied in the paper too. The results show that both fiber type and resin type have an obvious influence on tensile mechanical properties of sprayed FRP. There will be a specific fiber volume ratio for sprayed FRP to obtain the best tensile mechanical property. The increase of fiber length can lead to better tensile performance, while that of composite thickness results in property degradation. The study can provide reference to popularization and application of sprayed FRP material used in structure reinforcement.

  7. Mechanical properties of the human Achilles tendon, in vivo

    DEFF Research Database (Denmark)

    Kongsgaard, M; Nielsen, C H; Hegnsvad, S

    2011-01-01

    Ultrasonography has been widely applied for in vivo measurements of tendon mechanical properties. Assessments of human Achilles tendon mechanical properties have received great interest. Achilles tendon injuries predominantly occur in the tendon region between the Achilles-soleus myotendinous...... junction and Achilles-calcaneus osteotendinous junction i.e. in the free Achilles tendon. However, there has been no adequate ultrasound based method for quantifying the mechanical properties of the free human Achilles tendon. This study aimed to: 1) examine the mechanical properties of the free human...

  8. Mechanical Properties of Moringa ( Moringa oleifera ) Seeds in ...

    African Journals Online (AJOL)

    Mechanical properties are very important in the design of machines and the analysis of the behaviour of products during agricultural processing. In this research work, the mechanical properties of Moringa were determined as design parameters for the development of an oil expeller for the crop. The properties were the ...

  9. Food mechanical properties and dietary ecology.

    Science.gov (United States)

    Berthaume, Michael A

    2016-01-01

    Interdisciplinary research has benefitted the fields of anthropology and engineering for decades: a classic example being the application of material science to the field of feeding biomechanics. However, after decades of research, discordances have developed in how mechanical properties are defined, measured, calculated, and used due to disharmonies between and within fields. This is highlighted by "toughness," or energy release rate, the comparison of incomparable tests (i.e., the scissors and wedge tests), and the comparison of incomparable metrics (i.e., the stress and displacement-limited indices). Furthermore, while material scientists report on a myriad of mechanical properties, it is common for feeding biomechanics studies to report on just one (energy release rate) or two (energy release rate and Young's modulus), which may or may not be the most appropriate for understanding feeding mechanics. Here, I review portions of materials science important to feeding biomechanists, discussing some of the basic assumptions, tests, and measurements. Next, I provide an overview of what is mechanically important during feeding, and discuss the application of mechanical property tests to feeding biomechanics. I also explain how 1) toughness measures gathered with the scissors, wedge, razor, and/or punch and die tests on non-linearly elastic brittle materials are not mechanical properties, 2) scissors and wedge tests are not comparable and 3) the stress and displacement-limited indices are not comparable. Finally, I discuss what data gathered thus far can be best used for, and discuss the future of the field, urging researchers to challenge underlying assumptions in currently used methods to gain a better understanding between primate masticatory morphology and diet. © 2016 Wiley Periodicals, Inc.

  10. Physicochemical and phytochemical properties of cold and hot water extraction from Hibiscus sabdariffa.

    Science.gov (United States)

    Ramirez-Rodrigues, Milena M; Plaza, Maria L; Azeredo, Alberto; Balaban, Murat O; Marshall, Maurice R

    2011-04-01

    Hibiscus cold (25 °C) and hot (90 °C) water extracts were prepared in various time-temperature combinations to determine equivalent extraction conditions regarding their physicochemical and phytochemical properties. Equivalent anthocyanins concentration was obtained at 25 °C for 240 min and 90 °C for 16 min. Total phenolics were better extracted with hot water that also resulted in a higher antioxidant capacity in these extracts. Similar polyphenolic profiles were observed between fresh and dried hibiscus extracts. Hibiscus acid and 2 derivatives were found in all extracts. Hydroxybenzoic acids, caffeoylquinic acids, flavonols, and anthocyanins constituted the polyphenolic compounds identified in hibiscus extracts. Two major anthocyanins were found in both cold and hot extracts: delphynidin-3-sambubioside and cyanidin-3-sambubioside. In general, both cold and hot extractions yielded similar phytochemical properties; however, under cold extraction, color degradation was significantly lower and extraction times were 15-fold longer. Hibiscus beverages are prepared from fresh or dried calyces by a hot extraction and pasteurized, which can change organoleptic, nutritional, and color attributes. Nonthermal technologies such as dense phase carbon dioxide may maintain their fresh-like color, flavor, and nutrients. This research compares the physicochemical and phytochemical changes resulting from a cold and hot extraction of fresh and dried hibiscus calyces and adds to the knowledge of work done on color, quality attributes, and antioxidant capacity of unique tropical products. In addition, the research shows how these changes could lead to alternative nonthermal processes for hibiscus.

  11. Effect of pre-swelling of coal on its solvent extraction and liquefaction properties

    Energy Technology Data Exchange (ETDEWEB)

    Hengfu Shui; Zhicai Wang; Meixia Cao [Anhui University of Technology, Ma' anshan (China). School of Chemistry and Chemical Engineering

    2008-10-15

    Effects of pre-swelling of coal on solvent extraction and liquefaction properties were studied with Shenhua coal. It was found that pre-swelling treatments of the coal in three solvents, i.e., toluene (TOL), N-methyl-2-pyrrolidinone (NMP) and tetralin (THN) increased its extraction yield and liquefaction conversion, and differed the liquefied product distributions. The pre-swollen coals after removing the swelling solvents showed increased conversion in liquefaction compared with that of the swollen coals in the presence of swelling solvents. It was also found that the yields of (oil + gas) in liquefaction of the pre-swollen coals with NMP and TOL dramatically decreased in the presence of swelling solvent. TG and FTIR analyses of the raw coal, the swollen coals and the liquefied products were carried out in order to investigate the mechanism governing the effects of pre-swelling treatment on coal extraction and liquefaction. The results showed that the swelling pre-treatment could disrupt some non-covalent interactions of the coal molecules, relax its network structure and loosened the coal structure. It would thus benefit diffusion of a hydrogen donor solvent into the coal structure during liquefaction, and also enhance the hydrogen donating ability of the hydrogen-rich species derived from the coal. 21 refs., 4 figs., 3 tabs.

  12. Influence of cobalt, tantalum, and tungsten on the microstructure and mechanical properties of superalloy single crystals

    International Nuclear Information System (INIS)

    Nathal, M.V.; Ebert, L.J.

    1982-01-01

    The influence of Co, Ta, and W on the microstructure and mechanical properties of nickel base super-alloy single crystals was investigated. A matrix of alloys was based on Mar-M 247 stripped of C, B, Zr, and Hf. The microstructures of the alloys were examined using optical and electron microscopy, phase extraction, X-ray diffraction, and differential thermal analysis. Tensile and creep-rupture tests were performed at 1000 C. An increase in tensile and creep strength resulted when Co was removed from alloys containing high refractory metal contents, but Co effects were negligible for alloys with lower refractory metal levels. In the composition range studied, W was more effective than Ta in increasing the creep resistance. The mechanical properties are discussed in relation to the microstructures of the alloys

  13. Influence of cobalt, tantalum, and tungsten on the microstructure and mechanical properties of superalloy single crystals

    Science.gov (United States)

    Nathal, M. V.; Ebert, L. J.

    1982-01-01

    The influence of Co, Ta, and W on the microstructure and mechanical properties of nickel base super-alloy single crystals was investigated. A matrix of alloys was based on Mar-M 247 stripped of C, B, Zr, and Hf. The microstructures of the alloys were examined using optical and electron microscopy, phase extraction, X-ray diffraction, and differential thermal analysis. Tensile and creep-rupture tests were performed at 1000 C. An increase in tensile and creep strength resulted when Co was removed from alloys containing high refractory metal contents, but Co effects were negligible for alloys with lower refractory metal levels. In the composition range studied, W was more effective than Ta in increasing the creep resistance. The mechanical properties are discussed in relation to the microstructures of the alloys.

  14. Production of surgical gloves from low extractable protein RVNRL

    Energy Technology Data Exchange (ETDEWEB)

    Marga, Utama; Yanti, S.; Made, Sumarti; Marsongko; Tita, Puspitasari; Dian, Iramani [Center for Research and Development of Isotopes and Radiation Technology, National Nuclear Energy Agency, Jakarta (Indonesia); Makuuchi, K. [EB System Cooperation, Takasaki, Gunma (Japan); Yoshii, F. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Siswanto [Research Unit for Biotechnology of Estate Crop (Indonesia)

    2001-03-01

    Study on the production of surgical gloves from low extractable protein PVNRL (Radiation Vulcanization of Natural Rubber Latex) in home industry scale with normal butyl acrylate as sensitizer has been carried out. The variation of dipping speed, concentration of coagulant agent and selection of antioxidant for producing good quality of surgical gloves were evaluated. The water-extractable protein and PBS (Phosphate Buffer Saline) - extractable protein content, the physical and mechanical properties of gloves were measured. The results show that for producing a good quality of surgical gloves from low extractable protein RVNRL, the concentration of latex is 50% with calcium nitrate as coagulant agent between 15-20%. By using this condition the physical and mechanical properties of surgical gloves is required to ASTM standard such as tensile strength more than 24 MPa, PBS-extractable protein is around 41-68 ug/g and water-extractable protein contents is around 23-35 ug/g. (author)

  15. An Experimental Study to Measure the Mechanical Properties of the Human Liver.

    Science.gov (United States)

    Karimi, Alireza; Shojaei, Ahmad

    2018-01-01

    Since the liver is one of the most important organs of the body that can be injured during trauma, that is, during accidents like car crashes, understanding its mechanical properties is of great interest. Experimental data is needed to address the mechanical properties of the liver to be used for a variety of applications, such as the numerical simulations for medical purposes, including the virtual reality simulators, trauma research, diagnosis objectives, as well as injury biomechanics. However, the data on the mechanical properties of the liver capsule is limited to the animal models or confined to the tensile/compressive loading under single direction. Therefore, this study was aimed at experimentally measuring the axial and transversal mechanical properties of the human liver capsule under both the tensile and compressive loadings. To do that, 20 human cadavers were autopsied and their liver capsules were excised and histologically analyzed to extract the mean angle of a large fibers population (bundle of the fine collagen fibers). Thereafter, the samples were cut and subjected to a series of axial and transversal tensile/compressive loadings. The results revealed the tensile elastic modulus of 12.16 ± 1.20 (mean ± SD) and 7.17 ± 0.85 kPa under the axial and transversal loadings respectively. Correspondingly, the compressive elastic modulus of 196.54 ± 13.15 and 112.41 ± 8.98 kPa were observed under the axial and transversal loadings respectively. The compressive axial and transversal maximum/failure stress of the capsule were 32.54 and 37.30 times higher than that of the tensile ones respectively. The capsule showed a stiffer behavior under the compressive load compared to the tensile one. In addition, the axial elastic modulus of the capsule was found to be higher than that of the transversal one. The findings of the current study have implications not only for understanding the mechanical properties of the human capsule tissue under tensile

  16. Review of research on the mechanical properties of the human tooth

    Science.gov (United States)

    Zhang, Ya-Rong; Du, Wen; Zhou, Xue-Dong; Yu, Hai-Yang

    2014-01-01

    ‘Bronze teeth' reflect the mechanical properties of natural teeth to a certain extent. Their mechanical properties resemble those of a tough metal, and the gradient of these properties lies in the direction from outside to inside. These attributes confer human teeth with effective mastication ability. Understanding the various mechanical properties of human teeth and dental materials is the basis for the development of restorative materials. In this study, the elastic properties, dynamic mechanical properties (visco-elasticity) and fracture mechanical properties of enamel and dentin were reviewed to provide a more thorough understanding of the mechanical properties of human teeth. PMID:24743065

  17. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, Uthamalingam

    1995-01-01

    A composition and method of preparing YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T.sub.c. About 5-20% additions give rise to substantially improved mechanical properties.

  18. Yellow Mealworm Protein for Food Purposes - Extraction and Functional Properties.

    Directory of Open Access Journals (Sweden)

    Xue Zhao

    Full Text Available A protocol for extraction of yellow mealworm larvae proteins was established, conditions were evaluated and the resulting protein extract was characterised. The freeze-dried yellow mealworm larvae contained around 33% fat, 51% crude protein and 43% true protein on a dry matter basis. The true protein content of the protein extract was about 75%, with an extraction rate of 70% under optimised extraction conditions using 0.25 M NaOH, a NaOH solution:ethanol defatted worm ratio of 15:1 mL/g, 40°C for 1 h and extraction twice. The protein extract was a good source of essential amino acids. The lowest protein solubility in distilled water solution was found between pH 4 and 5, and increased with either increasing or decreasing pH. Lower solubility was observed in 0.5 M NaCl solution compared with distilled water. The rheological tests indicated that temperature, sample concentration, addition of salt and enzyme, incubation time and pH alterations influenced the elastic modulus of yellow mealworm protein extract (YMPE. These results demonstrate that the functional properties of YMPE can be modified for different food applications.

  19. Yellow Mealworm Protein for Food Purposes - Extraction and Functional Properties

    Science.gov (United States)

    Zhao, Xue; Vázquez-Gutiérrez, José Luis; Johansson, Daniel P.; Landberg, Rikard; Langton, Maud

    2016-01-01

    A protocol for extraction of yellow mealworm larvae proteins was established, conditions were evaluated and the resulting protein extract was characterised. The freeze-dried yellow mealworm larvae contained around 33% fat, 51% crude protein and 43% true protein on a dry matter basis. The true protein content of the protein extract was about 75%, with an extraction rate of 70% under optimised extraction conditions using 0.25 M NaOH, a NaOH solution:ethanol defatted worm ratio of 15:1 mL/g, 40°C for 1 h and extraction twice. The protein extract was a good source of essential amino acids. The lowest protein solubility in distilled water solution was found between pH 4 and 5, and increased with either increasing or decreasing pH. Lower solubility was observed in 0.5 M NaCl solution compared with distilled water. The rheological tests indicated that temperature, sample concentration, addition of salt and enzyme, incubation time and pH alterations influenced the elastic modulus of yellow mealworm protein extract (YMPE). These results demonstrate that the functional properties of YMPE can be modified for different food applications. PMID:26840533

  20. MODELLING OF RING-SHAPED ULTRASONIC WAVEGUIDES FOR TESTING OF MECHANICAL PROPERTIES AND THERAPEUTIC TREATMENT OF BIOLOGICAL TISSUES

    Directory of Open Access Journals (Sweden)

    V. T. Minchenya

    2011-01-01

    Full Text Available The article presents results of modelling of ring-shaped waveguide tool for ultrasonic treatment of biological materials, particularly malignant tumours, and testing of their mechanical properties. Harmonic analysis of forced flexural vibration of the waveguide using ANSYS software and APDL programming language was implemented for determination of waveguide geometric parameters providing its resonance for the given excitation frequency. The developed finite element model accounts for interaction between the waveguide and tumour tissue as well as initial prestressing of tissue radially compressed by the waveguide. Resonant curves of the waveguide in terms of its thickness and diameter are calculated and presented. Principle of application of the developed modeling technique for extraction of diagnostic data on mechanical properties of biological tissues is described.

  1. Comparative analysis of adsorption and corrosion inhibitive properties of ethanol extract of Dialium Guineense leaves for mild steel in 0.5 M HCl

    Directory of Open Access Journals (Sweden)

    Shola Elijah Adeniji

    2018-05-01

    Full Text Available Adsorption and corrosion inhibitive properties of ethanol extract of Dialium guineense leaves for mild steel in 0.5M HCl was studied using the gravimetric method. The results showed that the ethanol extract of Dialium guineense leaves is a good corrosion inhibitor for mild steel in 0.5 M HCl. The inhibition efficiency was found to increase with increase in the concentration of ethanol extract of Dialium guineense leaves up to the maximum of 92 %, but at the same time it decreased as the temperature was increased. Corrosion inhibition by the extract of Dialium guineense leaves is carried out by adsorption mechanism with the kinetics of corrosion following the pseudo first order reaction with high correlation. Thermodynamic consideration revealed that adsorption of the ethanol extract of Dialium guineense leaves on mild steel surface is an exothermic and spontaneous process that fitted the Langmuir adsorption isotherm. The values of activation energy and Gibb’s free energy were found within the range of limits expected for the mechanism of physical adsorption.

  2. Effects of hot water pre-extraction on surface properties of bagasse soda pulp.

    Science.gov (United States)

    Cordeiro, Nereida; Ashori, Alireza; Hamzeh, Yahya; Faria, Marisa

    2013-03-01

    In this work, the effects of hot water pre-extraction of depithed bagasse on the soda pulping and surface properties were studied. The conditions of hot water pre-extraction were: maximum temperature 170 °C, heat-up time 90 min, time at maximum temperature 10 min, and solid to liquor ratio (S:L) 1:8. Consequently, the pre-extracted and un-extracted bagasse chips were subjected to soda pulping at 160 °C for 1h with 11, 14 and 17% active alkali charge and an S:L of 1:5. The results showed that the hot water pre-extraction increased bagasse surface texture porosity by hemicellulose degradation. Therefore, the delignification was faster for pulping of pre-extracted samples. At a certain charge of alkali, pre-extracted samples showed higher screened yield and lower Kappa number. For instance, at 17% alkali charge, pre-extracted bagasse gave 11.3% higher pulp yield compared with the un-extracted ones. Inverse gas chromatography (IGC) results showed that the hot water pre-extraction changed the active sites on the bagasse surface, decreasing the dispersive energy and the basicity character, and affected the particle morphology. The pulping process decreased the hydrophobicity and the basicity of the bagasse surface. The surfaces of un-extracted and pre-extracted bagasse pulps had similar properties but different morphology. The pulps present higher surface area and permeability with more reactive capacity. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Effect of Extrusion on the Mechanical and Rheological Properties of a Reinforced Poly(Lactic Acid): Reprocessing and Recycling of Biobased Materials.

    Science.gov (United States)

    Peinado, Víctor; Castell, Pere; García, Lidia; Fernández, Ángel

    2015-10-19

    The aim of this research paper is to study the behaviour of a common used biopolymer (Poly(Lactic Acid) (PLA)) after several reprocesses and how two different types of additives (a melt strength enhancer and a nanoadditive) affect its mechanical and rheological properties. Systematic extraction of extrudate samples from a twin-screw compounder was done in order to study the effect in the properties of the reprocessed material. Detailed rheological tests on a capillary rheometer as well as mechanical studies on a universal tensile machine after preparation of injected specimens were carried out. Results evidenced that PLA and reinforced PLA materials can be reprocessed and recycled without a remarkable loss in their mechanical properties. Several processing restrictions and specific phenomena were identified and are explained in the present manuscript.

  4. The influence of extraction methods on composition and antioxidant properties of rice bran oil

    Directory of Open Access Journals (Sweden)

    Noppawat Pengkumsri

    2015-09-01

    Full Text Available AbstractThe current study was employed to assess the influence of the different extraction methods on total tocols, γ-oryzanol content, and antioxidant properties of Chiang Mai Black rice, Mali Red rice, and Suphanburi-1 Brown rice bran oil. Rice bran oil (RBO was extracted by Hexane, Hot pressed, Cold pressed, and Supercritical Fluid Extraction (SFe methods. High yield of RBO was extracted by hexane and SFe methods. Total and subgroups of tocols, and γ-oryzanol content were determined by HPLC. The hexane extracted sample accounts for high content of γ-oryzanol and tocols. Besides, all of RBO extracts contain a significantly high amount of γ-tocotrienol. In vitro antioxidant assay results indicated that superior quality of oil was recovered by hexane extraction. The temperature in the extraction process also affects the value of the oil. Superior quality of oil was recovered by hexane extraction, in terms of phytochemical contents and antioxidant properties compared to other tested extraction methods. Further, thorough study of factors compromising the quality and quantity of RBO recovery is required for the development of enhanced functional foods and other related products.

  5. Enhancement of mechanical properties of 123 superconductors

    Science.gov (United States)

    Balachandran, U.

    1995-04-25

    A composition and method are disclosed of preparing YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} superconductor. Addition of tin oxide containing compounds to YBCO superconductors results in substantial improvement of fracture toughness and other mechanical properties without affect on T{sub c}. About 5-20% additions give rise to substantially improved mechanical properties.

  6. Xenopus egg extract: A powerful tool to study genome maintenance mechanisms.

    Science.gov (United States)

    Hoogenboom, Wouter S; Klein Douwel, Daisy; Knipscheer, Puck

    2017-08-15

    DNA repair pathways are crucial to maintain the integrity of our genome and prevent genetic diseases such as cancer. There are many different types of DNA damage and specific DNA repair mechanisms have evolved to deal with these lesions. In addition to these repair pathways there is an extensive signaling network that regulates processes important for repair, such as cell cycle control and transcription. Despite extensive research, DNA damage repair and signaling are not fully understood. In vitro systems such as the Xenopus egg extract system, have played, and still play, an important role in deciphering the molecular details of these processes. Xenopus laevis egg extracts contain all factors required to efficiently perform DNA repair outside a cell, using mechanisms conserved in humans. These extracts have been used to study several genome maintenance pathways, including mismatch repair, non-homologous end joining, ICL repair, DNA damage checkpoint activation, and replication fork stability. Here we describe how the Xenopus egg extract system, in combination with specifically designed DNA templates, contributed to our detailed understanding of these pathways. Copyright © 2017. Published by Elsevier Inc.

  7. Effects of Sample and Indenter Configurations of Nanoindentation Experiment on the Mechanical Behavior and Properties of Ductile Materials

    Directory of Open Access Journals (Sweden)

    Seyed Saeid Rahimian Koloor

    2018-06-01

    Full Text Available The nanoindentation test is frequently used as an alternate method to obtain the mechanical properties of ductile materials. However, due to the lack of information about the effects of the sample and indenter physical configurations, the accuracy of the extracted material properties in nanoindentation tests requires further evaluation that has been considered in this study. In this respect, a demonstrator ductile material, aluminum 1100, was tested using the Triboscope nanoindenter system with the Berkovich indenter. A 3D finite element simulation of the nanoindentation test was developed and validated through exact prediction of the structural response with measured data. The validated model was then employed to examine the effects of various test configurations on the load–displacement response of the sample material. These parameters were the different indenter edge-tip radii, different indentation depths, different sample tilts, and different friction conditions between the indenter and the material surface. Within the range of the indenter edge-tip radii examined, the average elastic modulus and hardness were 78.34 ± 14.58 and 1.6 ± 0.24 GPa, respectively. The different indentation depths resulted in average values for the elastic modulus and hardness of 77.03 ± 6.54 and 1.58 ± 0.17 GPa, respectively. The uneven surface morphology, as described by the inclination of the local indentation plane, indicated an exponential increase in the extracted values of elastic modulus and hardness, ranging from 71.83 and 1.47 GPa (for the reference case, θ = 0° to 243.39 and 5.05 GPa at θ = 12°. The mechanical properties that were obtained through nanoindentation on the surface with 6° tilt or higher were outside the range for aluminum properties. The effect of friction on the resulting mechanical response and the properties of the material was negligible.

  8. Extraction and chemical characterization of rye arabinoxylan and the effect of β-glucan on the mechanical and barrier properties of cast arabinoxylan films

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Tenkanen, Maija; Pitkänen, Leena

    2013-01-01

    .9 and 1.0 cm3 mm/m2 d kPa). However, the water vapor permeability increased with addition of increasing amounts of BG to WE-AX. To our knowledge, this is the first study on the effect of β-glucans on the material and permeability properties of arabinoxylan-based films. © 2012 Elsevier Ltd. All rights......Water-extractable hemicellulose (WEH) fractions, containing approximately 65% arabinoxylans (WE-AX) and 20% mixed-linkage b-glucans were isolated from rye bran. In addition, water-extractable mixedlinkage β-glucans (BG) were isolated from oat bran as a reference material. The β-glucan content....../mol. The material properties of films prepared from the rye hemicellulose isolate and WE-AX as such, or with varying amounts of added BG (20:80; 50:50; 80:20 ratios) were studied. Prior removal of β-glucan from the isolate decreased the tensile strength of the films significantly as well as the elongation at break...

  9. Chitosan films incorporated with nettle (Urtica dioica L.) extract-loaded nanoliposomes: I. Physicochemical characterisation and antimicrobial properties.

    Science.gov (United States)

    Haghju, Sara; Beigzadeh, Sara; Almasi, Hadi; Hamishehkar, Hamed

    2016-07-17

    The objective of this study was to characterise and compare physical, mechanical and antimicrobial properties of chitosan-based films, containing free or nanoencapsulated nettle (Urtica dioica L.) extract (NE) at concentrations of 0, 0.5, 1 and 1.5% w/w. Nanoliposomes were prepared using soy-lecithin by thin-film hydration and sonication method to generate an average size of 107-136 nm with 70% encapsulation efficiency. The information on FT-IR reflected that some new interaction have occurred between chitosan and nanoliposomes. Despite the increasing yellowness and decreasing whiteness indexes, the nanoliposomes incorporation improved the thermal properties and mechanical stiffness and caused to decrease water vapour permeability (WVP), moisture uptake and water solubility. The possible antimicrobial activity of the films containing NE-loaded nanoliposomes against Staphylococcus aureus was decreased in comparison to free NE-incorporated films, which could be due to the inhibition effect of the encapsulation that prevents the release of NE from the matrix.

  10. Antitumor effects and mechanisms of Ganoderma extracts and spores oil

    OpenAIRE

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-01-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ga...

  11. Antioxidant properties of methanol extract of a new commercial ...

    African Journals Online (AJOL)

    White variety of Auricularia fuscosuccinea is a newly cultivated gelatinous mushrooms which is found only in Taiwan. In this study, total phenolic and total flavonoid content of methanol extract of white variety of A. fuscosuccinea was estimated, and in vitro antioxidant properties and antioxidant enzyme activities were also ...

  12. Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment

    Directory of Open Access Journals (Sweden)

    Mianmian Bao

    2018-03-01

    Full Text Available Previous study has shown that Ti-3Cu alloy shows good antibacterial properties (>90% antibacterial rate, but the mechanical properties still need to be improved. In this paper, a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy. Microstructure, mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction, optical microscope, scanning electron microscope, transmission electron microscopy, electrochemical measurements, tensile test, fatigue test and antibacterial test. Heat treatment could significantly improve the mechanical properties, corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti2Cu phase. Solid solution treatment increased the yield strength from 400 to 740 MPa and improved the antibacterial rate from 33% to 65.2% while aging treatment enhanced the yield strength to 800–850 MPa and antibacterial rate (>91.32%. It was demonstrated that homogeneous distribution and fine Ti2Cu phase plays a very important role in mechanical properties, corrosion resistance and antibacterial properties.

  13. Optimization of mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy by heat treatment.

    Science.gov (United States)

    Bao, Mianmian; Liu, Ying; Wang, Xiaoyan; Yang, Lei; Li, Shengyi; Ren, Jing; Qin, Gaowu; Zhang, Erlin

    2018-03-01

    Previous study has shown that Ti-3Cu alloy shows good antibacterial properties (>90% antibacterial rate), but the mechanical properties still need to be improved. In this paper, a series of heat-treatment processes were selected to adjust the microstructure in order to optimize the properties of Ti-3Cu alloy. Microstructure, mechanical properties, biocorrosion properties and antibacterial properties of wrought Ti-3Cu alloy at different conditions was systematically investigated by X-ray diffraction, optical microscope, scanning electron microscope, transmission electron microscopy, electrochemical measurements, tensile test, fatigue test and antibacterial test. Heat treatment could significantly improve the mechanical properties, corrosion resistance and antibacterial rate due to the redistribution of copper elements and precipitation of Ti 2 Cu phase. Solid solution treatment increased the yield strength from 400 to 740 MPa and improved the antibacterial rate from 33% to 65.2% while aging treatment enhanced the yield strength to 800-850 MPa and antibacterial rate (>91.32%). It was demonstrated that homogeneous distribution and fine Ti 2 Cu phase plays a very important role in mechanical properties, corrosion resistance and antibacterial properties.

  14. Antitumor effects and mechanisms of Ganoderma extracts and spores oil

    Science.gov (United States)

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-01-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC50) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle. PMID:27900038

  15. Structure–mechanics property relationship of waste derived biochars

    Energy Technology Data Exchange (ETDEWEB)

    Das, Oisik, E-mail: odas566@aucklanduni.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Sarmah, Ajit K., E-mail: a.sarmah@auckland.ac.nz [Department of Civil and Environmental Engineering, University of Auckland, Auckland 1142 (New Zealand); Bhattacharyya, Debes, E-mail: d.bhattacharyya@auckland.ac.nz [Department of Mechanical Engineering, Center for Advanced Composite Materials, University of Auckland, Auckland 1142 (New Zealand)

    2015-12-15

    The widespread applications of biochar in agriculture and environmental remediation made the scientific community ignore its mechanical properties. Hence, to examine the scope of biochar's structural applications, its mechanical properties have been investigated in this paper through nanoindentation technique. Seven waste derived biochars, made under different pyrolysis conditions and from diverse feedstocks, were studied via nanoindentation, infrared spectroscopy, X–ray crystallography, thermogravimetry, and electron microscopy. Following this, an attempt was made to correlate the biochars' hardness/modulus with reaction conditions and their chemical properties. The pine wood biochar made at 900 °C and 60 min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01 GPa, respectively. It was shown that a combination of higher heat treatment (≥ 500 °C) temperature and longer residence time (~ 60 min) increases the values of hardness and modulus. It was further realized that pyrolysis temperature was a more dominant factor than residence time in determining the final mechanical properties of biochar particles. The degree of aromaticity and crystallinity of the biochar were also correlated with higher values of hardness and modulus. - Highlights: • Characterization was done on waste based biochars which included nanoindentation. • Pine saw dust biochar made at 900 °C for 60 min had highest hardness/modulus. • Combination of temperature/residence time affect biochar's mechanical propertie.s • Aromaticity and crystallinity positively affected biochar's mechanical properties.

  16. Structure–mechanics property relationship of waste derived biochars

    International Nuclear Information System (INIS)

    Das, Oisik; Sarmah, Ajit K.; Bhattacharyya, Debes

    2015-01-01

    The widespread applications of biochar in agriculture and environmental remediation made the scientific community ignore its mechanical properties. Hence, to examine the scope of biochar's structural applications, its mechanical properties have been investigated in this paper through nanoindentation technique. Seven waste derived biochars, made under different pyrolysis conditions and from diverse feedstocks, were studied via nanoindentation, infrared spectroscopy, X–ray crystallography, thermogravimetry, and electron microscopy. Following this, an attempt was made to correlate the biochars' hardness/modulus with reaction conditions and their chemical properties. The pine wood biochar made at 900 °C and 60 min residence time was found to have the highest hardness and elastic modulus of 4.29 and 25.01 GPa, respectively. It was shown that a combination of higher heat treatment (≥ 500 °C) temperature and longer residence time (~ 60 min) increases the values of hardness and modulus. It was further realized that pyrolysis temperature was a more dominant factor than residence time in determining the final mechanical properties of biochar particles. The degree of aromaticity and crystallinity of the biochar were also correlated with higher values of hardness and modulus. - Highlights: • Characterization was done on waste based biochars which included nanoindentation. • Pine saw dust biochar made at 900 °C for 60 min had highest hardness/modulus. • Combination of temperature/residence time affect biochar's mechanical propertie.s • Aromaticity and crystallinity positively affected biochar's mechanical properties.

  17. Metal Additive Manufacturing: A Review of Mechanical Properties

    Science.gov (United States)

    Lewandowski, John J.; Seifi, Mohsen

    2016-07-01

    This article reviews published data on the mechanical properties of additively manufactured metallic materials. The additive manufacturing techniques utilized to generate samples covered in this review include powder bed fusion (e.g., EBM, SLM, DMLS) and directed energy deposition (e.g., LENS, EBF3). Although only a limited number of metallic alloy systems are currently available for additive manufacturing (e.g., Ti-6Al-4V, TiAl, stainless steel, Inconel 625/718, and Al-Si-10Mg), the bulk of the published mechanical properties information has been generated on Ti-6Al-4V. However, summary tables for published mechanical properties and/or key figures are included for each of the alloys listed above, grouped by the additive technique used to generate the data. Published values for mechanical properties obtained from hardness, tension/compression, fracture toughness, fatigue crack growth, and high cycle fatigue are included for as-built, heat-treated, and/or HIP conditions, when available. The effects of test orientation/build direction on properties, when available, are also provided, along with discussion of the potential source(s) (e.g., texture, microstructure changes, defects) of anisotropy in properties. Recommendations for additional work are also provided.

  18. The effect of selected supercritical CO2 plant extract addition on user properties of shower gels

    Directory of Open Access Journals (Sweden)

    Vogt Otmar

    2014-12-01

    Full Text Available The formulations of washing cosmetics i.e. shower gels, containing extracts obtained during supercritical CO2 extraction process as active ingredient, were developed. The subject of the study was the analysis of the physicochemical and user properties of the obtained products. In the work supercritical CO2 extracts of black currant seeds, strawberry seeds, hop cones and mint leafs were used. The formulation contains a mixture of surfactants (disodium cocoamphodiacetate, disodium laureth sulfosuccinate, cocoamide DEA, cocoamidepropyl betaine, Sodium Laureth Sulfate. Various thickener agents were applied to the obtained desired rheological properties of the cosmetics. Among others, sorbitol acetal derivatives, methylhydroxypropylcellulose and C10-30 alkyl acrylate crosspolymer were used. For stable products, the effect of extracts addition (black currants seeds, strawberries seeds, mint and hops, obtained from supercritical CO2 extraction process on the cosmetics properties, such as pH, viscosity, detergency and foam ability, were determined. The obtained results showed that the extracts could be used as components of shower gels.

  19. Withania somnifera Root Extract Enhances Chemotherapy through 'Priming'.

    Directory of Open Access Journals (Sweden)

    Aine Brigette Henley

    Full Text Available Withania somnifera extracts are known for their anti-cancerous, anti-inflammatory and antioxidative properties. One of their mechanisms of actions is to modulate mitochondrial function through increasing oxidative stress. Recently 'priming' has been suggested as a potential mechanism for enhancing cancer cell death. In this study we demonstrate that 'priming', in HT-29 colon cells, with W. somnifera root extract increased the potency of the chemotherapeutic agent cisplatin. We have also showed the W. somnifera root extract enhanced mitochondrial dysfunction and that the underlying mechanism of 'priming' was selectively through increased ROS. Moreover, we showed that this effect was not seen in non-cancerous cells.

  20. Antimicrobial properties of nudibranchs tissues extracts from South Andaman, India

    Directory of Open Access Journals (Sweden)

    Kota Veeraswamy Reddy

    2015-07-01

    Full Text Available Objective: To evaluate the antimicrobial properties of tissues extracts of different nudibranchs such as Phyllidia varicosa, Plakobranchus ocellatus, Phyllidiella rosans and Halgerda stricklandi against bacterial and fungal pathogens. Methods: Nudibranchs tissue samples were subjected to organic solvent extraction for antimicrobial activity by well diffusion method. Results: The crude extract 50 μL (0.2 mg of Phyllidia varicosa showed the maximum inhibitory zone (22 mm against Shigella flexneri. Plakobranchus ocellatus extract of 50 μL (0.2 mg showed the maximum inhibitory zone against Shigella flexneri (22 mm and Staphylococcus aureus (19 mm and no significant activity was found against the fungal pathogens. Conclusions: This work reveals that nudibranch tissues contain the antimicrobial secondary metabolites, which leads the significant activity against bacterial pathogens and further emphasizes detailed study on novel drug discovery from nudibranch tissues against certain human bacterial infections.

  1. Mechanical properties of fracture zones

    International Nuclear Information System (INIS)

    Leijon, B.

    1993-05-01

    Available data on mechanical characteristics of fracture zones are compiled and discussed. The aim is to improve the basis for adequate representation of fracture zones in geomechanical models. The sources of data researched are primarily borehole investigations and case studies in rock engineering, involving observations of fracture zones subjected to artificial load change. Boreholes only yield local information about the components of fracture zones, i.e. intact rock, fractures and various low-strength materials. Difficulties are therefore encountered in evaluating morphological and mechanical properties of fracture zones from borehole data. Although often thought of as macroscopically planar features, available field data consistently show that fracture zones are characterized by geometrical irregularities such as thickness variations, surface undulation and jogs. These irregularities prevail on all scales. As a result, fracture zones are on all scales characterized by large, in-plane variation of strength- and deformational properties. This has important mechanical consequences in terms of non-uniform stress transfer and complex mechanisms of shear deformation. Field evidence for these findings, in particular results from the underground research laboratory in Canada and from studies of induced fault slip in deep mines, is summarized and discussed. 79 refs

  2. Mechanical properties of self-curing concrete (SCUC

    Directory of Open Access Journals (Sweden)

    Magda I. Mousa

    2015-12-01

    Full Text Available The mechanical properties of concrete containing self-curing agents are investigated in this paper. In this study, two materials were selected as self-curing agents with different amounts, and the addition of silica fume was studied. The self-curing agents were, pre-soaked lightweight aggregate (Leca; 0.0%, 10%, 15%, and 20% of volume of sand; or polyethylene-glycol (Ch.; 1%, 2%, and 3% by weight of cement. To carry out this study the cement content of 300, 400, 500 kg/m3, water/cement ratio of 0.5, 0.4, 0.3 and 0.0%, 15% silica fume of weight of cement as an additive were used in concrete mixes. The mechanical properties were evaluated while the concrete specimens were subjected to air curing regime (in the laboratory environment with 25 °C, 65% R.H. during the experiment. The results show that, the use of self-curing agents in concrete effectively improved the mechanical properties. The concrete used polyethylene-glycol as self-curing agent, attained higher values of mechanical properties than concrete with saturated Leca. In all cases, either 2% Ch. or 15% Leca was the optimum ratio compared with the other ratios. Higher cement content and/or lower water/cement ratio lead(s to more efficient performance of self-curing agents in concrete. Incorporation of silica fume into self-curing concrete mixture enhanced all mechanical properties, not only due to its pozzolanic reaction, but also due to its ability to retain water inside concrete.

  3. PVA/Polysaccharides Blended Films: Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Fábio E. F. Silva

    2013-01-01

    Full Text Available Blends of polyvinyl alcohol (PVA and angico gum (AG and/or cashew gum (CG were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO. The films presented thickness varying from 70 to 140 μm (PVA/AG and 140 to 200 μm (PVA/CG. Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher values of tensile strength (TS and elastic modulus (EM were observed in the film. On the other hand, PVA/CG and PVA/CG-AG presented the highest value of percentage of elongation (E%. Pearson’s Correlation Analysis revealed a positive correlation between TS and EM and a negative correlation between E% and EM. The PVA/CG film presented mechanical properties very similar to MBO, with the advantage of a higher E% (11.96 than MBO (2.94. The properties of the PVA blended films depended on the polysaccharide added in the blend, as well as the acid used as a catalyst. However, all produced films presented interesting mechanical characteristics which enables several biotechnological applications.

  4. Mechanical properties of human atherosclerotic intima tissue.

    Science.gov (United States)

    Akyildiz, Ali C; Speelman, Lambert; Gijsen, Frank J H

    2014-03-03

    Progression and rupture of atherosclerotic plaques in coronary and carotid arteries are the key processes underlying myocardial infarctions and strokes. Biomechanical stress analyses to compute mechanical stresses in a plaque can potentially be used to assess plaque vulnerability. The stress analyses strongly rely on accurate representation of the mechanical properties of the plaque components. In this review, the composition of intima tissue and how this changes during plaque development is discussed from a mechanical perspective. The plaque classification scheme of the American Heart Association is reviewed and plaques originating from different vascular territories are compared. Thereafter, an overview of the experimental studies on tensile and compressive plaque intima properties are presented and the results are linked to the pathology of atherosclerotic plaques. This overview revealed a considerable variation within studies, and an enormous dispersion between studies. Finally, the implications of the dispersion in experimental data on the clinical applications of biomechanical plaque modeling are presented. Suggestions are made on mechanical testing protocol for plaque tissue and on using a standardized plaque classification scheme. This review identifies the current status of knowledge on plaque mechanical properties and the future steps required for a better understanding of the plaque type specific material properties. With this understanding, biomechanical plaque modeling may eventually provide essential support for clinical plaque risk stratification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Probing cell mechanical properties with microfluidic devices

    Science.gov (United States)

    Rowat, Amy

    2012-02-01

    Exploiting flow on the micron-scale is emerging as a method to probe cell mechanical properties with 10-1000x advances in throughput over existing technologies. The mechanical properties of cells and the cell nucleus are implicated in a wide range of biological contexts: for example, the ability of white blood cells to deform is central to immune response; and malignant cells show decreased stiffness compared to benign cells. We recently developed a microfluidic device to probe cell and nucleus mechanical properties: cells are forced to deform through a narrow constrictions in response to an applied pressure; flowing cells through a series of constrictions enables us to probe the ability of hundreds of cells to deform and relax during flow. By tuning the constriction width so it is narrower than the width of the cell nucleus, we can specifically probe the effects of nuclear physical properties on whole cell deformability. We show that the nucleus is the rate-limiting step in cell passage: inducing a change in its shape to a multilobed structure results in cells that transit more quickly; increased levels of lamin A, a nuclear protein that is key for nuclear shape and mechanical stability, impairs the passage of cells through constrictions. We are currently developing a new class of microfluidic devices to simultaneously probe the deformability of hundreds of cell samples in parallel. Using the same soft lithography techniques, membranes are fabricated to have well-defined pore distribution, width, length, and tortuosity. We design the membranes to interface with a multiwell plate, enabling simultaneous measurement of hundreds of different samples. Given the wide spectrum of diseases where altered cell and nucleus mechanical properties are implicated, such a platform has great potential, for example, to screen cells based on their mechanical phenotype against a library of drugs.

  6. In vitro antioxidant property of the extract of Excoecaria agallocha (Euphorbiaceae

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Background and objectives: Excoecaria agallocha L. (Family: Euphorbiaceae is a Bangladeshi medicinal plant found predominantly in the tidal forests and swamps of the Sundarbans and other coastal areas in Bangladesh.  As part of our on-going phytochemical and bioactivity studies on medicinal plants from Bangladeshi flora, the in vitro antioxidant property on the bark of this plant was evaluated. Methods: The hydroalcohol extract of the dried and ground bark of E. agallocha was assessed for antioxidant activity using a series of well-established assays including the 2,2-diphenyl-1-picrylhydrazyl (DPPH, the lipid peroxidation by thiobarbituric acid (TBA, the reducing power, the nitric oxide (NO. and the hydrogen peroxide (H2O2 scavenging assays. Results: In the DPPH, the NO and the H2O2 scavenging assays, the extract of E. agallocha displayed significant antioxidant activities with the IC50 values of 179.16, 120.24 and 134.29 μg/ml, respectively.  The reducing power of the extract increased dose-dependently, and the extract reduced the most Fe3+ ions to the extent less than butylated hydroxy toluene (BHT. In the lipid peroxidation assay, the extract showed significant inhibition of peroxidation effect at all concentrations, with an IC50 value of 189.27 μg/ml. Conclusion: Since reactive oxygen species are important contributors to serious ailments such as atherosclerosis, alcoholic liver cirrhosis and cancer, the antioxidant property of the extract of E. agallocha as observed in the present study might be useful for the development of newer and more potent antioxidants.

  7. Effect of zirconium addition on the microstructure and mechanical properties of 15Cr-ODS ferritic Steels consolidated by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Haijian, E-mail: haijianxu@eis.hokudai.ac.jp [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Material Science and Engineering, Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Lu, Zheng; Wang, Dongmei; Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China)

    2017-01-15

    The influence of Zr addition on the microstructure and mechanical properties of mechanically alloyed (MA) ODS ferritic steels were studied in this work. The microstructure characteristics included the grain size, oxide particles number densities, size distributions, crystal structures and compositions. TEM foils measurements were complemented by studies of alloys on carbon extraction replica and focus ion beam (FIB) foils. The tensile properties were carried out at different temperatures. The microstructure and mechanical properties were analyzed and compared with nominal compositions (wt.%): Fe-15Cr-2W-0.3Y{sub 2}O{sub 3} and Fe-15Cr −2W-0.3Zr-0.3Y{sub 2}O{sub 3}. The experimental revealed that the addition of Zr increased the volume fraction of the smallest and equiaxed ferritic grains, number density of nano-oxide particles and decreased the average size of oxide particles within the ferritic matrix, promoting the formation of fine trigonal δ-phase Y{sub 4}Zr{sub 3}O{sub 12} nano-oxides and leading to the enhancement of the mechanical properties of the ODS steels.

  8. Some Antifungal Properties of Sorbic Acid Extracted from Berries of Rowan (Sorbus Aucuparia).

    Science.gov (United States)

    Brunner, Ulrich

    1985-01-01

    The food preservative sorbic acid can be extracted from Eurasian mountain ash berries (commercially available) and used to show antifungal properties in microbiological investigations. Techniques for extraction, purification, ultraviolet analysis, and experiments displaying antifungal activity are described. A systematic search for similar…

  9. Phytochemical screening and analysis of antioxidant properties of aqueous extract of wheatgrass.

    Science.gov (United States)

    Durairaj, Varalakshmi; Hoda, Muddasarul; Shakya, Garima; Babu, Sankar Pajaniradje Preedia; Rajagopalan, Rukkumani

    2014-09-01

    To screen the phytochemical constituents and study antioxidant properties of the aqueous extract of the wheatgrass. The current study was focused on broad parameters namely, phytochemical analysis, gas chromatography-mass spectrometry analysis and antioxidant properties in order to characterize the aqueous extract of wheatgrass as a potential free radical quencher. The phytochemical screening of the aqueous extract of wheatgrass showed the presence of various secondary metabolites but the absence of sterols and quinone in general. Wheatgrass was proved to be an effective radical scavenger in all antioxidant assays. The gas chromatography-mass spectrometry analysis confirmed the presence of diverse category of bioactive compounds such as squalene, caryophyllene and amyrins in varying percentage. From the results obtained, we conclude that wheatgrass aqueous extract contains various effective compounds. It is a potential source of natural antioxidants. Further analysis of this herb will help in finding new effective compounds which can be of potent use in pharmacological field. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  10. Bioactive glass/hydroxyapatite composites: mechanical properties and biological evaluation.

    Science.gov (United States)

    Bellucci, Devis; Sola, Antonella; Anesi, Alexandre; Salvatori, Roberta; Chiarini, Luigi; Cannillo, Valeria

    2015-06-01

    Bioactive glass/hydroxyapatite composites for bone tissue repair and regeneration have been produced and discussed. The use of a recently developed glass, namely BG_Ca/Mix, with its low tendency to crystallize, allowed one to sinter the samples at a relatively low temperature thus avoiding several adverse effects usually reported in the literature, such as extensive crystallization of the glassy phase, hydroxyapatite (HA) decomposition and reaction between HA and glass. The mechanical properties of the composites with 80wt.% BG_Ca/Mix and 20wt.% HA are sensibly higher than those of Bioglass® 45S5 reference samples due to the presence of HA (mechanically stronger than the 45S5 glass) and to the thermal behaviour of the BG_Ca/Mix, which is able to favour the sintering process of the composites. Biocompatibility tests, performed with murine fibroblasts BALB/3T3 and osteocites MLO-Y4 throughout a multi-parametrical approach, allow one to look with optimism to the produced composites, since both the samples themselves and their extracts do not induce negative effects in cell viability and do not cause inhibition in cell growth. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Effect of the imposition of low-frequency mechanical oscillations on the extraction efficiency

    Directory of Open Access Journals (Sweden)

    Ju. I. Shitshatskij

    2018-01-01

    Full Text Available It was shown that the effective transfer of the target component from the raw material occurs under a turbulent regime conditions provided by applying mechanical oscillations to a two-phase system: solid-liquid. Due to this hydrodynamic situation, not only external but also internal diffusion is intensified in the extractor. The method for intensifying the extraction process using low-frequency mechanical oscillations in the case when the vibrational motion is performed by a device with a cheese whey containing suspended porous particles was studied in the work. The experiments were carried out on the laboratory equipment with a supply to a two-phase energy system from the outside, the source of which in the first case was an electromagnet, in the second - a mechanical drive with an eccentric device. Schemes of equipment were also presented in the work. The regime parameters varied in the following ranges: temperature - 40-60 оС, oscillation frequency - 30 - 40 osc / s, amplitude - 1 - 6.5 mm. In the extraction process, the current concentration of extractive substances was obtained from the material balance equation. Extraction curves obtained from experimental data were presented. Increasing extraction of extractive substances in time was observed, it being more intense with the increasing frequency of oscillations. It was found that the growth of the amplitude does not have a significant influence on the change of these indices. The intensity of oscillations was up to 260 mm / s. At the same time, the yield of extractive substances in particular from lupine in the form of grits was 25%, and the duration of the process was 18 min. The experiments showed that the application of the chosen extraction method results into a significant acceleration of the process (up to 2.5 times as compared to extraction in a dense layer. It is concluded that due to the imposition of mechanical oscillations on the surface and in the pores of the solid phase

  12. Variability of standard artificial soils: Physico-chemical properties and phenanthrene desorption measured by means of supercritical fluid extraction

    International Nuclear Information System (INIS)

    Bielská, Lucie; Hovorková, Ivana; Komprdová, Klára; Hofman, Jakub

    2012-01-01

    The study is focused on artificial soil which is supposed to be a standardized “soil like” medium. We compared physico-chemical properties and extractability of Phenanthrene from 25 artificial soils prepared according to OECD standardized procedures at different laboratories. A substantial range of soil properties was found, also for parameters which should be standardized because they have an important influence on the bioavailability of pollutants (e.g. total organic carbon ranged from 1.4 to 6.1%). The extractability of Phe was measured by supercritical fluid extraction (SFE) at harsh and mild conditions. Highly variable Phe extractability from different soils (3–89%) was observed. The extractability was strongly related (R 2 = 0.87) to total organic carbon content, 0.1–2 mm particle size, and humic/fulvic acid ratio in the following multiple regression model: SFE (%) = 1.35 * sand (%) − 0.77 * TOC (%)2 + 0.27 * HA/FA. - Highlights: ► We compared properties and extractability of Phe from 25 different artificial soils. ► Substantial range of soil properties was found, also for important parameters. ► Phe extractability was measured by supercritical fluid extraction (SFE) at 2 modes. ► Phe extractability was highly variable from different soils (3–89%). ► Extractability was strongly related to TOC, 0.1–2 mm particles, and HA/FA. - Significant variability in physico-chemical properties exists between artificial soils prepared at different laboratories and affects behavior of contaminants in these soils.

  13. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea–formaldehyde (UF) resin based polymer matrix has been reported. Static mechanical properties of randomly oriented intimately mixed ...

  14. Mechanical properties of carbon nanotubes

    Science.gov (United States)

    Salvetat, J.-P.; Bonard, J.-M.; Thomson, N. H.; Kulik, A. J.; Forró, L.; Benoit, W.; Zuppiroli, L.

    A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing. These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a qualitative relationship between the Young's modulus of a nanotube and the amount of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before suitable engineering materials can be produced.

  15. Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Trung Dung; Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia)

    2014-05-05

    Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

  16. Antioxidant and Ex Vivo Immune System Regulatory Properties of Boswellia serrata Extracts

    Directory of Open Access Journals (Sweden)

    Daniela Beghelli

    2017-01-01

    Full Text Available Boswellia serrata (BS is an important traditional medicinal plant that currently represents an interesting topic for pharmaceutical research since it possesses several pharmacological properties (e.g., anti-inflammatory, antimicrobial, and antitumour. The safety and versatility of this dietary supplement should allow for its use in numerous pathological conditions; however the quality of the extracts needs to be standardized to increase the clinical success rate resulting from its use. In the present study, different commercially available B. serrata extracts were employed to compare their AKBA content and in vitro antioxidant power. Furthermore, their ability to modulate the immune system regulatory properties was investigated. Our results showed that the AKBA content varied from 3.83±0.10 to 0.03±0.004%, with one sample in which it was not detectable. The highest antioxidant power and phenolic content were shown by the same extract, which also exhibited the highest AKBA concentration. Finally, the BS extracts showed the ability to influence the regulatory and effector T-cell compartments. Our results suggest that frankincense should be further investigated for its promising potentiality to modulate not only inflammation/oxidative stress but also immune dysregulation, but attention should be paid to the composition of the commercial extracts.

  17. Understanding the effect of flower extracts on the photoconducting properties of nanostructured TiO2.

    Science.gov (United States)

    Ansari, S G; Bhayana, Laitka; Umar, Ahmad; Al-Hajry, A; Al-Deyab, Salem S; Ansari, Z A

    2012-10-01

    Here we report an easy method to improve the optoelectronic properties of commercially available TiO2 nanopowder using extracts of various flowers viz. Calendula Orange (CO), Calendula Yellow (CY), Dahlia Violet (DV), Dahlia Yellow (DY), Rabbit flower (RF), Sweet Poppy (SP), Sweet Williams (SW) and their Mixed Extracts (ME). Various analysis techniques such as UV-Vis, FTIR, FESEM, XRD, and Raman spectroscopy were used to characterize for elemental, structural and morphological properties of the unmixed/mixed TiO2 nanopowder. TiO2 nanopowder was also calcined at 550 degrees C. Thick films of the these unmixed/mixed powder were printed, using conventional screen printing method, on fluorine doped tin oxide (FTO) substrate with organic binders and dried at 45 degrees C. The photoconducting properties are investigated as a function of wavelength from ultra-violet (UV) to infra-red (IR) region at a constant illumination intensity. Photocurrent gradually decreases when irradiated from UV to IR region. In case of unmixed and uncalcined TiO2, conductance decreased continuously whereas when extracts are added, a flat region of conductance is observed. The overall effect of extracts (colour pigments) is seen as an increase in the photoconductance. Highest photoconductance is observed in case of DY flower extract. Anthocyanins, present in flowers are known to have antioxidative properties and hence can contribute in photoconduction by reducing the surface adsorbed oxygen. This investigation indicates the potential use of flower extracts for dye sensitized solar cell (DSSC).

  18. Investigation of the Effects of Rosemary Extract on Barrier and Colorimetric Properties of Mungbean Starch Films

    Directory of Open Access Journals (Sweden)

    H. Safari Maznabi

    2013-08-01

    Full Text Available Barrier properties are one of the most important factors in the edible film. In this study, edible mungbean films were prepared containing (0%, 15%, 30%, 45% concentrations of rosemary aqueous extract. Then the effect of rosemary was investigated on colorimetric and barrier properties (water vapor permeability, oxygen permeability. Rosemary extract increased the absorption of color in the visible region, which in turn led to increase of the parameters a (index color tends toward green and b (index color tends towards yellow. The results showed that increasing concentrations of rosemary extract have a significant effect( p <0.05 to reduce the amount of oxygen and water vapor permeability.  Also turbidity of mungbean starch was increased with increasing concentrations of rosemary in the film. Improving barrier properties and the colorimetric properties were showed by rosemary extract compounds that these materials can use as the safety of food and pharmaceutical packaging industry.

  19. Investigation of the effects of excipients on technological properties tablets of pyrola rotundifolia extract

    OpenAIRE

    Darzuli, Natalia; Hroshovyi, Taras; Sokolova, Kateryna; Podpletnyaya, Elena

    2018-01-01

    Aim of the work. To study the influence of excipients on the pharmacological and technological properties of round-leaved wintergreen extract tablets.Methods. The subject of the study were 27 series of round-leaved wintergreen extract tablets. The study of the influence of excipients on the pharmacological and technological properties of tablets, namely: abrasion, strength, disintegration, homogeneity were carried out in accordance with the requirements of SPhU 2 edition. The appearance of ta...

  20. Dynamic mechanical properties of buffer material

    International Nuclear Information System (INIS)

    Takaji, Kazuhiko; Taniguchi, Wataru

    1999-11-01

    The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (i) it has exceptionally low water permeability and properties to control the movement of water in buffer, (ii) it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (iii) it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. We can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests. (author)

  1. Molecular mechanisms in compatibility and mechanical properties of Polyacrylamide/Polyvinyl alcohol blends.

    Science.gov (United States)

    Wei, Qinghua; Wang, Yanen; Che, Yu; Yang, Mingming; Li, Xinpei; Zhang, Yingfeng

    2017-01-01

    The objectives of this study were to develop a computational model based on molecular dynamics technique to investigate the compatibility and mechanical properties of Polyacrylamide (PAM)/Polyvinyl alcohol (PVA) blends. Five simulation models of PAM/PVA with different composition ratios (4/0, 3/1, 2/2, 1/3, 0/4) were constructed and simulated by using molecular dynamics (MD) simulation. The interaction mechanisms of molecular chains in PAM/PVA blend system were elaborated from the aspects of the compatibility, mechanical properties, binding energy and pair correlation function, respectively. The computed values of solubility parameters for PAM and PVA indicate PAM has a good miscibility with PVA. The results of the static mechanical analysis, based on the equilibrium structures of blends with differing component ratios, shows us that the elastic coefficient, engineering modulus, and ductility are increased with the addition of PVA content, which is 4/0 PAM/PVAPVAPVAPVAPVA. Moreover, binding energy results indicate that a stronger interaction exists among PVA molecular chains comparing with PAM molecular chains, which is why the mechanical properties of blend system increasing with the addition of PVA content. Finally, the results of pair correlation functions (PCFs) between polar functional groups and its surrounding hydrogen atoms, indicated they interact with each other mainly by hydrogen bonds, and the strength of three types of polar functional groups has the order of O(-OH)>O(-C=O)>N(-NH 2 ). This further elaborates the root reason why the mechanical properties of blend system increase with the addition of PVA content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Measurement of the mechanical properties of layered systems

    International Nuclear Information System (INIS)

    Blank, E.

    2002-01-01

    Thin films for integrated electronic circuitry, packaging and small structures in micro-electromechanical systems (MEMS) as well as protective coatings require mechanical testing to control fabrication processes, guarantee product quality and establish data bases for engineering purposes. They generally escape classical materials testing owing to their small size in at least one dimension and their incorporation into larger structures. The fact that material properties change in the micro- and nanometer range when sample dimensions reach the scale of defect structures, implies that sample and probe size become part of the property evaluation process. Although research into the mechanical behaviour of thin films and small structures now is established, the fundamentals of mechanical testing continue to be identified while there is a growing need for methods allowing to measure intrinsic material properties. This lecture will focus on the mechanics of thin film and small volume structures and review recently developed testing techniques for measuring materials properties, particularly indentation, bulge and bend testing. The effect of specimen and probe geometry on property evaluation will be discussed. The use of Raman spectroscopy for residual stress measurement will be illustrated. (Author)

  3. SEPARATION OF p-AMINOBENZOIC ACID BY REACTIVE EXTRACTION. 1. MECHANISM AND INFLUENCING FACTORS

    Directory of Open Access Journals (Sweden)

    DAN CASCAVAL

    2008-09-01

    Full Text Available The comparative study on the reactive extraction of p-aminobenzoic acid with Amberlite LA-2 and D2EHPA in two solvents with different polarity (n-heptane and dichloromethane indicated that the extractant type and solvent polarity control the extraction mechanism. Thus, the reactive extraction with Amberlite LA-2 occurs by means of the interfacial formation of an aminic adduct with three extractant molecules in low-polar solvent, or of an salt with one extractant molecule in higher polar solvent. Similarly, the extraction with D2EHPA is based on the formation of an acidic adduct with two extractant molecules in n-heptane, or of a salt with one extractant molecule in dichloromethane. The most efficient extraction has been reached for the combination Amberlite LA-2-dichloromethane.

  4. Physicochemical and Antioxidant Properties of Rice Bran Oils Produced from Colored Rice Using Different Extraction Methods.

    Science.gov (United States)

    Mingyai, Sukanya; Kettawan, Aikkarach; Srikaeo, Khongsak; Singanusong, Riantong

    2017-06-01

    This study investigated the physicochemical and antioxidant properties of rice bran oil (RBO) produced from the bran of three rice varities; Khao Dawk Mali 105 (white rice), Red Jasmine rice (red rice) and Hom-nin rice (black rice) using three extraction methods including cold-press extraction (CPE), solvent extraction (SE) and supercritical CO 2 extraction (SC-CO 2 ). Yields, color, acid value (AV), free fatty acid (FFA), peroxide value (PV), iodine value (IV), total phenolic compound (TPC), γ-oryzanol, α-tocopherol and fatty acid profile were analyzed. It was found that the yields obtained from SE, SC-CO 2 and CPE extractions were 17.35-20.19%, 14.76-18.16% and 3.22-6.22%, respectively. The RBO from the bran of red and black rice samples exhibited high antioxidant activities. They also contained higher amount of γ-oryzanol and α-tocopherol than those of white rice sample. In terms of extraction methods, SC-CO 2 provided better qualities of RBO as evidenced by their physicochemical and antioxidant properties. This study found that RBO produced from the bran of black rice samples using SC-CO 2 extraction method showed the best physicochemical and antioxidant properties.

  5. Equilibrium and extraction mechanism from monomeric and polimeric species of zirconium in solution. part. 2

    International Nuclear Information System (INIS)

    Azevedo, H.L.P. de.

    1980-01-01

    The mechanism of extraction and the equilibrium of chemical species from Zirconium solutions was studied. The multiple extraction method was used to show the species envolved in the extraction process and qualitative informations was obtained about the equilibrium between extractable species (monomers) and non-extractable species (polymers) in the aqueous phase. (M.J.C.) [pt

  6. Potent Anti-Inflammatory and Antiadipogenic Properties of Bamboo (Sasa coreana Nakai) Leaves Extract and Its Major Constituent Flavonoids.

    Science.gov (United States)

    Yang, Ji Hye; Choi, Moon-Hee; Yang, Seung Hwa; Cho, Sam Seok; Park, Su Jung; Shin, Hyun-Jae; Ki, Sung Hwan

    2017-08-09

    The pro-inflammatory response and recruitment of macrophages into adipose tissue contribute to metabolic dysfunction. Here, we reported the anti-inflammatory and antiadipogenic effects of the methanol (MeOH) extract and ethyl acetate (EtOAc) fraction of bamboo leaf and its molecular mechanism in RAW264.7 cells and 3T3-L1 adipocytes, respectively. Functional macrophage migration assays also were performed. Surprisingly, the EtOAc fraction of MeOH extracts from native Korean plant species Sasa coreana Nakai (SCN) has shown potent anti-inflammatory properties; SCN pretreatment inhibited nitric oxide (NO) production (p 0.05). Similar to leaf extracts of other bamboo species, we identified that SCN contained several flavonoids including orientin, isoorientin, and vitexin; these compounds inhibited LPS-induced NO production (p flavonoids of SCN also inhibited adipogenesis. Furthermore, conditioned medium obtained from adipocytes stimulated macrophage chemotaxis, whereas medium from adipocytes treated with SCN significantly inhibited macrophage migration. Therefore, SCN is a potential therapeutic agent for the prevention of inflammation and obesity.

  7. Extraction behaviour and mechanism of Pt(iv) and Pd(ii) by liquid-liquid extraction with an ionic liquid [HBBIm]Br.

    Science.gov (United States)

    Liu, Wenhui; Wang, Qi; Zheng, Yan; Wang, Shubin; Yan, Yan; Yang, Yanzhao

    2017-06-06

    In this study, a method of one-step separation and recycling of high purity Pd(ii) and Pt(iv) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(ii) and precipitating Pt(iv). Through selectively extracting Pd(ii) and precipitating Pt(iv), each metal with high purity was separately obtained from mixed Pd(ii) and Pt(iv) multi-metal solution. The method of one-step separation of Pd(ii) and Pt(iv) is simple and convenient. The anion exchange mechanism between [HBBIm]Br and Pt(iv) was proven through Job's method and FTIR and 1 H NMR spectroscopies. The coordination mechanism between [HBBIm]Br and Pd(ii) was demonstrated via single X-ray diffraction and was found to be robust and distinct, as supported by the ab initio quantum-chemical studies. The crystals of the [PdBr 2 ·2BBIm] complex were formed first. Moreover, the influence of the concentrations of hydrochloric acid, sodium chloride, and sodium nitrate on the precipitation of Pt(iv) and extraction of Pd(ii) was studied herein. It was found that only the concentration of H + could inhibit the separation of Pt(iv) because H + could attract the anion PtCl 6 2- ; thus, the exchange (anion exchange mechanism) between the anions PtCl 6 2- and Br - was prevented. However, both the concentration of H + and Cl - can obviously inhibit the extraction of Pd(ii) because H + and Cl - are the reaction products and increasing their concentration can inhibit the progress of the reaction (coordination mechanism).

  8. Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties.

    Science.gov (United States)

    Katira, Parag; Bonnecaze, Roger T; Zaman, Muhammad H

    2013-01-01

    Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

  9. Influence of Storage on Briquettes Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Brožek M.

    2014-09-01

    Full Text Available The effects of the storage place, placing manner, and storage time on mechanical properties of briquettes made from birch chips were laboratorily tested. A unique methodology developed by the present author enabling a relatively easy assessment of mechanical properties of the briquettes is described. The briquettes properties were evaluated by their density and rupture force determination. From the test results it follows that if the briquettes are stored in a well closed plastic bag, neither the place nor the storage time influence significantly their life time. When stored in a net plastic bag, the briquettes get seriously damaged, namely depending on their storage place and storage time.

  10. Hydrophilic olive cake extracts: Characterization by physicochemical properties and Cu(II) complexation

    International Nuclear Information System (INIS)

    Kolokassidou, K.; Szymczak, W.; Wolf, M.; Obermeier, C.; Buckau, G.; Pashalidis, I.

    2009-01-01

    Disposed olive cake generates hydrophilic components that can be mobilized in the aquatic environment. This paper deals with the characterization of such components, isolated by alkaline extraction. It is shown that these substances possess properties very much resembling humic acid, including a substantial inventory of proton exchanging groups. Extraction and purification of the hydrophilic components from the disposed olive cake was performed by the standard approach for isolation of humic acids from solid sources, i.e. alternating alkaline dissolution and acid flocculation, leaving the purified extract in the protonated form. The purified sample was characterized by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Fourier Transform Infra Red Spectroscopy (FTIR), UV-vis, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Asymmetrical Flow Field-Flow Fractionation (AFFFF). The complex formation properties were investigated by potentiometry using Cu(II) ion selective electrode under atmospheric conditions at I = 0.1 M NaClO 4 (aqueous solution) and pH 6. The formation constant for the CuHA complex is found to be log β = 5.3 ± 0.4 which is close to the corresponding value (log β = 5.2 ± 0.4) obtained from similar investigations with the commercially available Aldrich humic acid (this study) and corresponding published values for various humic acids. Both, structural properties and complex formation data show that the olive cake extract has considerable similarities with humic acids from different sources, pointing towards potential similarities in environmental behavior and impact.

  11. Rationally designed synthetic protein hydrogels with predictable mechanical properties.

    Science.gov (United States)

    Wu, Junhua; Li, Pengfei; Dong, Chenling; Jiang, Heting; Bin Xue; Gao, Xiang; Qin, Meng; Wang, Wei; Bin Chen; Cao, Yi

    2018-02-12

    Designing synthetic protein hydrogels with tailored mechanical properties similar to naturally occurring tissues is an eternal pursuit in tissue engineering and stem cell and cancer research. However, it remains challenging to correlate the mechanical properties of protein hydrogels with the nanomechanics of individual building blocks. Here we use single-molecule force spectroscopy, protein engineering and theoretical modeling to prove that the mechanical properties of protein hydrogels are predictable based on the mechanical hierarchy of the cross-linkers and the load-bearing modules at the molecular level. These findings provide a framework for rationally designing protein hydrogels with independently tunable elasticity, extensibility, toughness and self-healing. Using this principle, we demonstrate the engineering of self-healable muscle-mimicking hydrogels that can significantly dissipate energy through protein unfolding. We expect that this principle can be generalized for the construction of protein hydrogels with customized mechanical properties for biomedical applications.

  12. Characterization and modelling of the mechanical properties of mineral wool

    DEFF Research Database (Denmark)

    Chapelle, Lucie

    2016-01-01

    and as a consequence focus on the mechanical properties of mineral wool has intensified. Also understanding the deformation mechanisms during compression of low density mineral wool is crucial since better thickness recovery after compression will result in significant savings on transport costs. The mechanical...... properties of mineral wool relate closely to the arrangement and characteristics of the fibres inside the material. Because of the complex architecture of mineral wool, the characterization and the understanding of the mechanism of deformations require a new methodology. In this PhD thesis, a methodology...... of the structure on mechanical properties can be explored. The size of the representative volume elements for the prediction of the elastic properties is determined for two types of applied boundary conditions. For sufficiently large volumes, the predicted elastic properties are consistent with results from...

  13. Predicting Soil-Air and Soil-Water Transport Properties During Soil Vapor Extraction

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe

    Increased application of in-situ technology for control and removal of volatile organic compounds (VOC) in the subsurface has made the understanding of soil physical properties and their impact upon contaminant transport even more important. Knowledge of contaminant transport is important when...... properties of undisturbed soil from more easily measurable soil properties are developed. The importance of soil properties with respect to contaminant migration during remediation by soil vapor extraction (SVE) in the unsaturated zone was investigated using numerical simulations....

  14. Mechanical properties of low dimensional materials

    Science.gov (United States)

    Saini, Deepika

    Recent advances in low dimensional materials (LDMs) have paved the way for unprecedented technological advancements. The drive to reduce the dimensions of electronics has compelled researchers to devise newer techniques to not only synthesize novel materials, but also tailor their properties. Although micro and nanomaterials have shown phenomenal electronic properties, their mechanical robustness and a thorough understanding of their structure-property relationship are critical for their use in practical applications. However, the challenges in probing these mechanical properties dramatically increase as their dimensions shrink, rendering the commonly used techniques inadequate. This dissertation focuses on developing techniques for accurate determination of elastic modulus of LDMs and their mechanical responses under tensile and shear stresses. Fibers with micron-sized diameters continuously undergo tensile and shear deformations through many phases of their processing and applications. Significant attention has been given to their tensile response and their structure-tensile properties relations are well understood, but the same cannot be said about their shear responses or the structure-shear properties. This is partly due to the lack of appropriate instruments that are capable of performing direct shear measurements. In an attempt to fill this void, this dissertation describes the design of an inexpensive tabletop instrument, referred to as the twister, which can measure the shear modulus (G) and other longitudinal shear properties of micron-sized individual fibers. An automated system applies a pre-determined twist to the fiber sample and measures the resulting torque using a sensitive optical detector. The accuracy of the instrument was verified by measuring G for high purity copper and tungsten fibers. Two industrially important fibers, IM7 carbon fiber and KevlarRTM 119, were found to have G = 17 and 2.4 GPa, respectively. In addition to measuring the shear

  15. Thermo-mechanical design of the extraction grids for RF negative ion source at HUST

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Chen; Liu, Kaifeng, E-mail: kfliuhust@hust.edu.cn; Li, Dong; Mei, Zhiyuan; Zhang, Zhe; Chen, Dezhi

    2017-01-15

    Highlights: • An extraction system with cooling channels has been designed for HUST negative ion source. • Corresponding heat loads onto three grids has been used in thermo-mechanical analysis. • The analysis results could be very useful for driving the engineering design. - Abstract: Huazhong University of Science and Technology (HUST) is developing a small radio frequency negative ion source experimental setup to promote research on neutral beam injection ion sources. The extraction system for the negative ion source is the key component to obtain the negative ions. The extraction system is composed of three grids: the plasma grid, the extraction grid and the grounded grid. Each grid is impacted by different heat loads. As the grids have to fulfil specific requirements regarding ion extraction, beam optics, and thermo-mechanical issues, grid cooling systems have been included for ensuring reliable operation. This paper focuses on the thermo-hydraulic and thermo-mechanical design of the grids. Finite element calculations have been carried out to analyse the temperature and deformation of the grids under heat loads using the fluid dynamics code CFX. Based on these results, the cooling circuit design and cooling parameters are optimised to satisfy the grid requirements.

  16. Engineering spray-dried rosemary extracts with improved physicomechanical properties: a design of experiments issue

    Directory of Open Access Journals (Sweden)

    Luiza T. Chaul

    Full Text Available ABSTRACT A 33 Box–Behnken design and Response Surface Methodology were performed to evaluate the influence of extract feed rate, drying air inlet temperature and spray nozzle airflow rate on the process yield, stability parameters (moisture content and water activity and on several physicomechanical properties of spray-dried rosemary extracts. Powder yield ranged from 17.1 to 74.96%. The spray-dried rosemary extracts showed moisture content and water activity below 5% and 0.5%, respectively, which indicate their chemical and microbiological stabilities. Even without using drying aids, some sets of experimental conditions rendered dried products with suitable flowability and compressibility characteristics for direct preparation of solid dosage forms. Analysis of variance and Response Surface Methodology proved that studied factors significantly affected most of the spray-dried rosemary extract quality indicators at different levels. The main processing parameter affecting the spray-dried rosemary extract characteristics was inlet temperature. The best combination of parameters used to obtain a reasonable yield of stable dry rosemary extracts with adequate technological properties for pharmaceutical purpose involves an extract feed rate of 2 ml/min, 80 °C inlet temperature and 40 l/min SA. The design of experiments approach is an interesting strategy for engineering spray-dried rosemary extracts with improved characteristics for pharmaceutical industrial purpose.

  17. Mechanical properties of additively manufactured octagonal honeycombs

    Energy Technology Data Exchange (ETDEWEB)

    Hedayati, R., E-mail: rezahedayati@gmail.com [Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran (Iran, Islamic Republic of); Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands); Sadighi, M.; Mohammadi-Aghdam, M. [Department of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran (Iran, Islamic Republic of); Zadpoor, A.A. [Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD Delft (Netherlands)

    2016-12-01

    Honeycomb structures have found numerous applications as structural and biomedical materials due to their favourable properties such as low weight, high stiffness, and porosity. Application of additive manufacturing and 3D printing techniques allows for manufacturing of honeycombs with arbitrary shape and wall thickness, opening the way for optimizing the mechanical and physical properties for specific applications. In this study, the mechanical properties of honeycomb structures with a new geometry, called octagonal honeycomb, were investigated using analytical, numerical, and experimental approaches. An additive manufacturing technique, namely fused deposition modelling, was used to fabricate the honeycomb from polylactic acid (PLA). The honeycombs structures were then mechanically tested under compression and the mechanical properties of the structures were determined. In addition, the Euler-Bernoulli and Timoshenko beam theories were used for deriving analytical relationships for elastic modulus, yield stress, Poisson's ratio, and buckling stress of this new design of honeycomb structures. Finite element models were also created to analyse the mechanical behaviour of the honeycombs computationally. The analytical solutions obtained using Timoshenko beam theory were close to computational results in terms of elastic modulus, Poisson's ratio and yield stress, especially for relative densities smaller than 25%. The analytical solutions based on the Timoshenko analytical solution and the computational results were in good agreement with experimental observations. Finally, the elastic properties of the proposed honeycomb structure were compared to those of other honeycomb structures such as square, triangular, hexagonal, mixed, diamond, and Kagome. The octagonal honeycomb showed yield stress and elastic modulus values very close to those of regular hexagonal honeycombs and lower than the other considered honeycombs. - Highlights: • The octagonal

  18. Mechanical properties of organic nanofibers

    DEFF Research Database (Denmark)

    Kjelstrup-Hansen, Jakob; Hansen, Ole; Rubahn, H.R.

    2006-01-01

    Intrinsic elastic and inelastic mechanical Properties of individual, self-assembled, quasi-single-crystalline para-hexaphenylene nanofibers supported on substrates with different hydrophobicities are investigated as well as the interplay between the fibers and the underlying substrates. We find...

  19. Recent Progress in the Development of Supercritical Carbon Dioxide-Soluble Metal Ion Extractants: Aggregation, Extraction, and Solubility Properties of Silicon-Substituted Alkylenediphosphonic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Mark L.; McAlister, Daniel R.; Stepinski, Dominique C.; Zalupski, Peter R.; Dzilawa, Julie A.; Barrans, Richard E.; Hess, J.N.; Rubas, Audris V.; Chiarizia, Renato; Lubbers, Christopher M.; Scurto, Aaron M.; Brennecke, Joan F.; Herlinger, Albert W.

    2003-09-11

    Partially esterified alkylenediphosphonic acids (DPAs) have been shown to be effective reagents for the extraction of actinide ions from acidic aqueous solution into conventional organic solvents. Efforts to employ these compounds in supercritical fluid extraction have been hampered by their modest solubility in unmodified supercritical carbon dioxide (SC-CO2). In an effort to design DPAs that are soluble in SC-CO2, a variety of silicon-substituted alkylenediphosphonic acids have been prepared and characterized, and their behavior compared with that of conventional alkyl-substituted reagents. Silicon substitution is shown to enhance the CO2-philicity of the reagents, while other structural features, in particular, the number of methylene groups bridging the phosphorus atoms of the extractant, are shown to exert a significant influence on their aggregation and extraction properties. The identification of DPAs combining desirable extraction properties with adequate solubility in SC-CO2 is shown to be facilitated by the application of molecular connectivity indices.

  20. Algorithm of extraction optics properties from the measurement of spatially resolved diffuse reflectance

    International Nuclear Information System (INIS)

    Cunill Rodriguez, Margarita; Delgado Atencio, Jose Alberto; Castro Ramos, Jorge; Vazquez y Montiel, Sergio

    2009-01-01

    There are several methods to obtain the optical parameters of biological tissues from the measurement of spatially resolved diffuse reflectance. One of them is well-known as Video Reflectometry in which a camera CCD is used as detection and recording system of the lateral distribution of diffuse reflectance Rd(r) when an infinitely narrow light beam impinges on the tissue. In this paper, we present an algorithm that we have developed for the calibration and application of an experimental set-up of Video Reflectometry destined to extract the optical properties of models of biological tissues with optical properties similar to the human skin. The results of evaluation of the accuracy of the algorithm for optical parameters extraction is shown for a set of proofs reflectance curves with known values of these parameters. In the generation of these curves the simulation of measurement errors was also considered. The results show that it is possible to extract the optical properties with an accuracy error of less than 1% for all the proofs curves. (Author)

  1. Dynamic mechanical properties and anisotropy of synthetic shales with different clay minerals under confining pressure

    Science.gov (United States)

    Gong, Fei; Di, Bangrang; Wei, Jianxin; Ding, Pinbo; Shuai, Da

    2018-03-01

    The presence of clay minerals can alter the elastic behaviour of reservoir rocks significantly as the type of clay minerals, their volume and distribution, and their orientation control the shale's intrinsic anisotropic behaviours. Clay minerals are the most abundant materials in shale, and it has been proven extremely difficult to measure the elastic properties of natural shale by means of a single variable (in this case, the type of clay minerals), due to the influences of multiple factors, including water, TOC content and complex mineral compositions. We used quartz, clay (kaolinite, illite and smectite), carbonate and kerogen extract as the primary materials to construct synthetic shale with different clay minerals. Ultrasonic experiments were conducted to investigate the anisotropy of velocity and mechanical properties in dry synthetic and natural shale as a function of confining pressure. Velocities in synthetic shale are sensitive to the type of clay minerals, possibly due to the different structures of the clay minerals. The velocities increase with confining pressure and show higher rate of velocity increase at low pressures, and P-wave velocity is usually more sensitive than S-wave velocity to confining pressure according to our results. Similarly, the dynamic Young's modulus and Poisson's ratio increase with applied pressure, and the results also reveal that E11 is always larger than E33 and ν31 is smaller than ν12. Velocity and mechanical anisotropy decrease with increasing stress, and are sensitive to stress and the type of clay minerals. However, the changes of mechanical anisotropy with applied stress are larger compared with the velocity anisotropy, indicating that mechanical properties are more sensitive to the change of rock properties.

  2. Extraction mechanism of Sc(III) from sulphuric acid solution by primary amine N1923

    International Nuclear Information System (INIS)

    Le Shaoming; Li Deqian; Ni Jiazan

    1987-01-01

    The extraction mechanism of Sc(III) from sulphuric acid solution by primary amine N 1923 (RNH 2 ) has been investigated by means of slope, isomolar continuous variation and saturation methods. The effect of temperature on the extraction of Sc(III) is observed. The extraction equilibrium constant and thermodynamic functions (ΔH, ΔS and ΔG) are obtained. The IR and NMR of extracted compound are measured

  3. MECHANICAL AND THERMO–MECHANICAL PROPERTIES OF BI-DIRECTIONAL AND SHORT CARBON FIBER REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    G. AGARWAL

    2014-10-01

    Full Text Available This paper based on bidirectional and short carbon fiber reinforced epoxy composites reports the effect of fiber loading on physical, mechanical and thermo-mechanical properties respectively. The five different fiber loading, i.e., 10wt. %, 20wt. %, 30wt. %, 40wt. % and 50wt. % were taken for evaluating the above said properties. The physical and mechanical properties, i.e., hardness, tensile strength, flexural strength, inter-laminar shear strength and impact strength are determined to represent the behaviour of composite structures with that of fiber loading. Thermo-mechanical properties of the material are measured with the help of Dynamic Mechanical Analyser to measure the damping capacity of the material that is used to reduce the vibrations. The effect of storage modulus, loss modulus and tan delta with temperature are determined. Finally, Cole–Cole analysis is performed on both bidirectional and short carbon fiber reinforced epoxy composites to distinguish the material properties of either homogeneous or heterogeneous materials. The results show that with the increase in fiber loading the mechanical properties of bidirectional carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, as far as Loss modulus, storage modulus is concerned bidirectional carbon fiber shows better damping behaviour than short carbon fiber reinforced composites.

  4. Methanol Extract of Codonopsis pilosula Inhibits Inducible Nitric ...

    African Journals Online (AJOL)

    Purpose: To evaluate the mechanism of antioxidant activity of the methanol extract of Codonopsis pilosula. Methods: Anti-oxidative properties were assessed by measuring free radical scavenging activity, nitric oxide (NO) levels, protein oxidation and reducing power, while the mechanism of antioxidative effect of ...

  5. Influence of the mechanical properties of resilient denture liners on the retention of overdenture attachments.

    Science.gov (United States)

    Kubo, Keitaro; Koike, Takashi; Ueda, Takayuki; Sakurai, Kaoru

    2018-03-15

    Information is lacking about the selection criteria for silicone resilient denture liners applied as a matrix material for attachments on overdentures. The purpose of this in vitro study was to investigate the mechanical properties of silicone resilient denture liners and their influence on the initial retention force of overdenture attachments and the reduction in retention force over time. Nine types of silicone resilient denture liner were injected and fixed to the matrix section of an experimental denture base. They were then fitted to an epoxy resin model that simulated the residual ridge with a patrix ball attachment (n=10). The retention force of the denture was measured with a digital force gauge, and the maximum force of traction (N) was regarded as the initial retention force. The retention force reduction (N) after repeated insertion and removal (n=5) was calculated by subtracting the retention force after 3348 cycles (3-year simulated insertion and removal) from the initial retention force. The intaglio of the matrix was observed with a scanning electron microscope (SEM) before and after the 3348 cycles. Four mechanical properties (hardness, strain-in-compression, tensile strength, and arithmetic mean roughness) of the resilient denture liners were measured. One-way ANOVA of the initial retention force of each lining material was performed, followed by the Scheffe test (α=.05). Pearson correlation analysis was used (α=.05) to analyze correlations of the initial retention force with the retention force reduction after insertion and removal and the mechanical properties of each material. Multiple regression analysis with the stepwise method extracted the initial retention force and the retention force reduction as dependent variables, and the resilient denture liner mechanical properties as explanatory variables (α=.05). The initial retention force of the resilient denture liners was 1.3 to 5.4 N. Multiple comparisons showed significant differences in

  6. Characterization of porosity in support of mechanical property analysis

    International Nuclear Information System (INIS)

    Price, R.H.; Martin, R.J. III; Boyd, P.J.

    1992-01-01

    Previous laboratory investigations of tuff have shown that porosity has a dominant, general effect on mechanical properties. As a result, it is very important for the interpretation of mechanical property data that porosity is measured on each sample tested. Porosity alone, however, does not address all of the issues important to mechanical behavior. Variability in size and distribution of pore space produces significantly different mechanical properties. A nondestructive technique for characterizing the internal structure of the sample prior to testing is being developed and the results are being analyzed. The information obtained from this technique can help in both qualitative and quantitative interpretation of test results

  7. Mechanical properties of F82H plates with different thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Sakasegawa, Hideo, E-mail: sakasegawa.hideo@jaea.go.jp; Tanigawa, Hiroyasu

    2016-11-01

    Highlights: • Mass effect, homogeneity, and anisotropy in mechanical properties were studied. • Thickness dependence of tensile property was not observed. • Thickness dependence of Charpy impact property was observed. • Appropriate mechanical properties were obtained using an electric furnace. - Abstract: Fusion DEMO reactor requires over 11,000 tons of reduced activation ferritic/martensitic steel and it is indispensable to develop the manufacturing technology for producing large-scale components of DEMO blanket with appropriate mechanical properties. This is because mechanical properties are generally degraded with increasing production volume. In this work, we focused mechanical properties of F82H–BA12 heat which was melted in a 20 tons electric arc furnace. Plates with difference thicknesses from 18 to 100 mm{sup t} were made from its ingot through forging and hot-rolling followed by heat treatments. Tensile and Charpy impact tests were then performed on plates focusing on their homogeneity and anisotropy. From the result, their homogeneity and anisotropy were not significant. No obvious differences were observed in tensile properties between the plates with different thicknesses. However, Charpy impact property changed with increasing plate thickness, i.e. the ductile brittle transition temperature of a 100 mm{sup t} thick plate was higher than that of the other thinner plates.

  8. Mechanical properties of self-compacting concrete state-of-the-art report of the RILEM technical committee 228-MPS on mechanical properties of self-compacting concrete

    CERN Document Server

    Schutter, Geert

    2014-01-01

    The State-of-the-Art Report of RILEM Technical Committee 228-MPS on Mechanical properties of Self-Compacting Concrete (SCC) summarizes an extensive body of information related to mechanical properties and mechanical behaviour of SCC. Due attention is given to the fact that the composition of SCC varies significantly. A wide range of  mechanical properties are considered, including compressive strength, stress-strain relationship, tensile and flexural strengths, modulus of elasticity, shear strength, effect of elevated temperature, such as fire spalling and residual properties after fire, in-situ properties, creep, shrinkage, bond properties, and structural behaviour. A chapter on fibre-reinforced SCC is included, as well as a chapter on specialty SCC, such as light-weight SCC, heavy-weight SCC, preplaced aggregate SCC, special fibre reinforced SCC, and underwater concrete.

  9. Anti-corrosion and Anti-bacteria Property of Modified Pomegranate Peel Extract

    Science.gov (United States)

    Gu, Xue-Fan; Chang, Xiao-Feng; Cheng, Chao; Zhang, Li; Zhang, Yong-Ming; Zhang, Jie; Chen, Gang

    2018-03-01

    Using weight loss method, the pomegranate peel extract (PPE), that is a green corrosion inhibitors, have been studied in the corrosion inhibition of Q235A steel in 1M hydrochloric acid solution at 30°C, 45°C, 60°C, respectively. The inhibition rate of extract varies with the extraction concentration in the range of 10 ∼ 1000mg / L, up to 92.7%. Extract inhibits corrosion through adsorption mechanisms. Besides polyphenols hydroxyl and ether groups can slow down corrosion by capturing H+. Polyphenols can remove the dissolved O2, and curb oxygen reducing corrosion. PPE is antifungal active against TGB and FB, but not so active against SRB.

  10. Size-dependent mechanical properties of 2D random nanofibre networks

    International Nuclear Information System (INIS)

    Lu, Zixing; Zhu, Man; Liu, Qiang

    2014-01-01

    The mechanical properties of nanofibre networks (NFNs) are size dependent with respect to different fibre diameters. In this paper, a continuum model is developed to reveal the size-dependent mechanical properties of 2D random NFNs. Since such size-dependent behaviours are attributed to different micromechanical mechanisms, the surface effects and the strain gradient (SG) effects are, respectively, introduced into the mechanical analysis of NFNs. Meanwhile, a modified fibre network model is proposed, in which the axial, bending and shearing deformations are incorporated. The closed-form expressions of effective modulus and Poisson's ratio are obtained for NFNs. Different from the results predicted by conventional fibre network model, the present model predicts the size-dependent mechanical properties of NFNs. It is found that both surface effects and SG effects have significant influences on the effective mechanical properties. Moreover, the present results show that the shearing deformation of fibre segment is also crucial to precisely evaluate the effective mechanical properties of NFNs. This work mainly aims to provide an insight into the micromechanical mechanisms of NFNs. Besides, this work is also expected to provide a more accurate theoretical model for 2D fibre networks. (paper)

  11. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  12. Crude ethanolic extract from spent coffee grounds: Volatile and functional properties.

    Science.gov (United States)

    Page, Julio C; Arruda, Neusa P; Freitas, Suely P

    2017-11-01

    Espresso capsule consumption and spent coffee ground (SCG) generation have increased, and the present study was undertaken to evaluate the volatile profile (VP), the antioxidant activity (AA) and the sun protection factor (SPF) of the Crude ethanolic extract obtained from the SCG in capsules. The extract yield was superior to the ether yield because a higher unsaponifiable matter (U.M.) amount was recovered by ethanol. The obtained VP (70 compounds) was typical of roasted coffee oil. Furthermore, chemometric analysis using principal components (PCA) discriminated the extracts and grouped the replicates for each sample, which showed the repeatability of the extraction process. The AA ranged from 18.4 to 23.6 (mg extract mg DPPH -1 ) and the SPF from 2.27 to 2.76. The combination of the coffee VP, AA and SPF gave the espresso SCG's crude ethanolicextract, desirable properties that can be used in cosmetic and food industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Microstructure and Mechanical Properties of Porous Mullite

    Science.gov (United States)

    Hsiung, Chwan-Hai Harold

    Mullite (3 Al2O3 : 2 SiO2) is a technologically important ceramic due to its thermal stability, corrosion resistance, and mechanical robustness. One variant, porous acicular mullite (ACM), has a unique needle-like microstructure and is the material platform for The Dow Chemical Company's diesel particulate filter AERIFY(TM). The investigation described herein focuses on the microstructure-mechanical property relationships in acicular mullites as well as those with traditional porous microstructures with the goal of illuminating the critical factors in determining their modulus, strength, and toughness. Mullites with traditional pore morphologies were made to serve as references via slipcasting of a kaolinite-alumina-starch slurry. The starch was burned out to leave behind a pore network, and the calcined body was then reaction-sintered at 1600C to form mullite. The samples had porosities of approximately 60%. Pore size and shape were altered by using different starch templates, and pore size was found to influence the stiffness and toughness. The ACM microstructure was varied along three parameters: total porosity, pore size, and needle size. Total porosity was found to dominate the mechanical behavior of ACM, while increases in needle and pore size increased the toughness at lower porosities. ACM was found to have much improved (˜130%) mechanical properties relative to its non-acicular counterpart at the same porosity. A second set of investigations studied the role of the intergranular glassy phase which wets the needle intersections of ACM. Removal of the glassy phase via an HF etch reduced the mechanical properties by ˜30%, highlighting the intergranular phase's importance to the enhanced mechanical properties of ACM. The composition of the glassy phase was altered by doping the ACM precursor with magnesium and neodymium. Magnesium doping resulted in ACM with greatly reduced fracture strength and toughness. Studies showed that the mechanical properties of the

  14. Mechanical properties used for the qualification of transport casks

    International Nuclear Information System (INIS)

    Salzbrenner, R.; Crenshaw, T.B.; Sorenson, K.B.

    1993-01-01

    The qualification process that should be sufficient for qualification of a specific cask (material/geometry combination) has been examined. The prototype cask should be tested to determine its overall variation in microstructure, chemistry, and mechanical properties. This prototype may also be subjected to 'proof testing' to demonstrate the validity of the design analysis (including the mechanical properties used in the analysis). The complete mechanical property mapping does not necessarily have to precede the proof testing (i.e., portions of the cask which experience only low (elastic) loads during the drop test are suitable for mechanical test specimens). The behavior of the prototype cask and the production casks are linked by assuring that each cask possesses at least the minimum level of one or more critical mechanical properties. This may be done by measuring the properties of interest directly, or by relying on a secondary measurement (such as subsize mechanical test results or microstructure/compositional measurements) which has been statistically correlated to the critical properties. The database required to show the correlation between the secondary measurement and the valid design property may be established by tests on the material from the prototype cask. The production controls must be demonstrated as being adequate to assure that a uniform product is produced. The testing of coring (or test block or prolongation) samples can only be viewed as providing a valid link to the benchmark results provided by the prototype cask if the process used to create follow-on casks remains essentially similar. The MOSAIK Test Program has demonstrated the qualification method through the benchmarking stage. The program did not establish for qualifying serial production casks through, for example, a correlation between small specimen parameters and valid design fracture toughness properties. Such a correlation would require additional experimental work. (J.P.N.)

  15. Sedative, membrane stability, cytotoxic and antioxidant properties of methanol extract of leaves of Protium serratum Wall.

    Directory of Open Access Journals (Sweden)

    Md. Rafikul Islam

    2014-09-01

    Full Text Available Objective: To study the sedative, membrane stability, cytotoxic and antioxidant properties of the leaves of Protium serratum extracted using methanol. Methods: Sedative test was performed using hole cross and open field methods at 200 and 400 mg/kg. Membrane stability of red blood cell was used for anti-inflammatory test at different concentrations. Cytotoxic study was performed using brine shrimp lethality test. Total flavonoid contents, total phenol contents and reducing power were used to assess antioxidant properties of the extract. Results: Extract showed better sedative action at lower doses in both experiments. Maximum 73.33% locomotion reduction was found at 200 mg/kg at 1 20 min and that was 89.29% for diazepam in hole cross test. In membrane stability test, extract and standard drug diclofenac have 35.66% and 91.20% stability, respectively. LC50 value of the extract was 22.91 µg/mL. Total phenol and flavonoid contents were (55.53依14.63 mg gallic acid equivalent per gram of extract and (1 06.33依7.35 mg of quercetin equivalent per gram of extract, respectively per gram of extract. Significant reducing power was observed as compared to ascorbic acid. Conclusions: Extract possesses good pharmacological properties. Hence, further extensive study is essential to find out possible active constituents for the treatment of anxiety, inflammation or sickle cell disease, cancer and free radical mediated abnormalities.

  16. Mechanism of mechanical property enhancement in nitrogen and titanium implanted 321 stainless steel

    International Nuclear Information System (INIS)

    Xu Ming; Li Liuhe; Liu Youming; Cai Xun; Chen Qiulong; Chu, Paul K.

    2006-01-01

    Ion implantation is a well-known method to modify surface mechanical properties. The improvement of the mechanical properties can usually be attributed to the formation of new strengthening phases, solution strengthening, dislocation strengthening, or grain refinement. However, in many cases, the roles of individual factors are not clear. In this study, we implanted nitrogen and titanium into 321 stainless steel samples to investigate the enhancement mechanism of the mechanical properties. Nano-indentation experiments were conducted to measure the hardness under various loadings. The N and Ti implanted 321 stainless steel samples were found to behave differently in the hardness (GPa) versus depth (nm) diagram. The effects of the radiation damage, solution strengthening, and dispersion strengthening phase were analyzed. Characterization of the modified layers was performed using techniques such as Auger electron spectroscopy (AES) and grazing incidence X-ray diffraction (GIXRD). Transmission electron microscopy (TEM) and X-ray diffraction were also applied to reveal the structure of the untreated 321 stainless steel

  17. Study of mechanical properties and recommendations for the application of waste Bakelite aggregate concrete

    Directory of Open Access Journals (Sweden)

    Nopagon Usahanunth

    2018-06-01

    Full Text Available Bakelite waste from industrial manufacturing may be a hazard to the environment and public health. The utilization of waste Bakelite (WB to replace natural aggregates (NA, such as natural coarse aggregate (NCA and natural fine aggregate (NFA, in concrete and mortar is an approach for reducing both waste plastic and natural material. This research examines the utilization of waste Bakelite aggregate (WBA in concrete and mortar mixtures to form waste Bakelite aggregate concrete (WBAC and waste Bakelite mortar (WBM. The tests cover the physical and chemical properties of WBA, the mechanical properties of WBAC and WBM (including the extraction of chemical substances from WBA utilization to replace NCA and NFA, and recommendations for the application of replacement. The results indicate that WBA particles of different sizes can replace both fine and coarse natural aggregates. Its weight is less than natural aggregate but the absorption rate is higher. As for recommendations for the application, it was found that replacing 20% of NCA with waste Bakelite coarse aggregate in concrete (WBAC-RNCA was the most suitable proportion, owing to its mechanical properties and safety for the environment and public health, and because its material cost is acceptable. However, the use of waste Bakelite fine aggregate to replace NFA (WBAC-RNFA in concrete is not appropriate, because its mechanical properties are not sufficient, and it is considered unsafe for the environment and health. Moreover, WBM is not a suitable material for plastering work, since it may be a hazard to the environment and public health, and its cost is higher than conventional mortar. Keywords: Waste Bakelite, Aggregate, Concrete, Mortar

  18. Potential Properties of Plant Sprout Extracts on Amyloid β

    Directory of Open Access Journals (Sweden)

    Mizue Okada

    2016-01-01

    Full Text Available The aim of this study is to examine the amyloid β (Aβ inhibition mechanism of plant sprouts’ aqueous extracts (PSAE. In this study, we screened the effects of five plant sprouts’ extracts on Aβ (1–42 structure modification using gel electrophoresis. In PSAE, no band of Aβ monomer was recognized in Japanese butterbur. Similarly, the Aβ monomer band became light in buckwheat, red cabbage, broccoli, and brussels. The neuroprotective effects of PSAE were evaluated by measuring levels of Aβ in mixtures (Aβ  and PSAE with Aβ ELISA assay. The treatment with PSAE decreased Aβ levels. The results indicated that the levels of red cabbage, Japanese butterbur, and broccoli were 9.6, 28.0, and 44.0%, respectively. The lowest value was observed with buckwheat. Furthermore, we carried out a Congo Red (CR and Aβ binding experiment of PSAE to confirm the modification mechanism of PSAE. The correlation coefficient for the absorption spectrum peak of CR was found to be bigger than 0.8 (r=0.882 which proved that the Aβ levels could be attributed to the peak of CR. In conclusion, we demonstrated that treatment with PSAE effectively decreases Aβ concentration. Thus, the mechanism that decreased the Aβ levels may be modification by PSAE.

  19. Stevia rebaudiana ethanolic extract exerts better antioxidant properties and antiproliferative effects in tumour cells than its diterpene glycoside stevioside.

    Science.gov (United States)

    López, Víctor; Pérez, Sergio; Vinuesa, Arturo; Zorzetto, Christian; Abian, Olga

    2016-04-01

    Steviol glycosides are currently being used as natural sweeteners by the food industry and Stevia rebaudiana has long been used as a sweet plant in South America for patients suffering from diabetes. In this study, a Stevia rebaudiana ethanolic extract (SREE) was prepared, analysed and tested for antioxidant activity in terms of free radical scavenging properties and antiproliferative effects in cervix (HeLa), pancreatic (MiaPaCa-2) and colonic (HCT116) cancer cells. The antiproliferative mechanism was confirmed by testing the effects on cyclin D1-CDK4. Bioassays were also performed for the diterpene glycoside stevioside. Our results demonstrate that the extract acts as an antioxidant being able to scavenge free radicals, but this activity was not due to stevioside. The extract also induced cell death in the three cell lines, being more active against cervix cancer cells (HeLa); however, the concentration of stevioside needed to produce antiproliferative effects was higher than the amount of steviol glycosides found in a lower dose of extract inducing cell death. In addition, the extract clearly inhibited CDK4 whereas stevioside did not, concluding that the antiproliferative activity of stevia may be due to inhibition of cyclin-dependent kinases performed by other compounds of the extract.

  20. SWCNT Composites, Interfacial Strength and Mechanical Properties

    DEFF Research Database (Denmark)

    Ma, Jing; Larsen, Mikael

    2013-01-01

    Abstract: Single-Walled Carbon Nanotubes (SWCNT) have despite the superior mechanical properties not fully lived up to the promise as reinforcement in SWCNT composites. The strain transfer from matrix to carbon nanotubes (CNT) is poorly understood and is caused by both fewer localized strong...... is applied to the composite materials. The effect of polymer matrix, modification and concentration of the CNTs are discussed. The strain transfer i.e. 2D band shift under tension is compared to the mechanical properties of the SWCNT composite material....

  1. Orthodontic space closure using simple mechanics in compromised first molar extraction spaces: Case series

    Directory of Open Access Journals (Sweden)

    Prashant M Dhole

    2018-01-01

    Full Text Available Orthodontic treatments involving missing or compromised first permanent molars are often challenging cases to treat considering the loss of potential anchor tooth. The case series presents orthodontic treatment in three patients with mutilated/absent first permanent molars. The treatment goals were to be accomplished by extraction of compromised teeth and retention of healthy dentition. The diagnosis and problem list needed extractions to accomplish the treatment goals. The possibility of extracting compromised first permanent molars instead of other healthy teeth was considered. A setup was done to determine the final occlusion in asymmetric extraction cases. Fixed appliances were used with simple mechanics without any additional anchorage devices. Case-based retention protocols were followed. All the three patients achieved the predetermined treatment objectives of improved esthetics and healthy and stable functional occlusion. The simple and efficient mechanics and finishing techniques for comprehensive orthodontic treatment with first molar extractions presented in the report should help clinicians when treating similar patients.

  2. The thermal and mechanical properties of electron beam-irradiated polylactide

    International Nuclear Information System (INIS)

    Kuk, In Seol; Jung, Chan Hee; Hwang, In Tae; Choi, Jae Hak; Nho, Young Chang

    2010-01-01

    The effect of electron beam irradiation on the thermal and mechanical properties of polylactide (PLA) was investigated in this research. PLA films were irradiated by electron beams at different absorption doses ranging from 20 to 200 kGy. The thermal and mechanical properties of the irradiated PLA films were investigated by means of differential scanning calorimeter, thermogravimetric analyzer, universal testing machine, dynamic mechanical analyzer, and thermal mechanical analyzer. The results revealed that the chain scission of the PLA predominated over the crosslinking during the irradiation, which considerably deteriorated the thermal and mechanical properties of the PLA

  3. Halloysite reinforced epoxy composites with improved mechanical properties

    Directory of Open Access Journals (Sweden)

    Saif Muhammad Jawwad

    2016-03-01

    Full Text Available Halloysite nanotubes (HNTs reinforced epoxy composites with improved mechanical properties were prepared. The prepared HNTs reinforced epoxy composites demonstrated improved mechanical properties especially the fracture toughness and flexural strength. The flexural modulus of nanocomposite with 6% mHNTs loading was 11.8% higher than that of neat epoxy resin. In addition, the nanocomposites showed improved dimensional stability. The prepared halloysite reinforced epoxy composites were characterized by thermal gravimetric analysis (TGA. The improved properties are attributed to the unique characteristics of HNTs, uniform dispersion of reinforcement and interfacial coupling.

  4. Extraction of fluoride metal complexes by octanols

    International Nuclear Information System (INIS)

    Baklanova, I.V.; Nikolaev, A.I.; Il'in, E.G.; Majorov, V.G.

    2005-01-01

    The extraction of niobium(V) and tantalum(V) by octanols, including 1-octanol, 2-octanol, and iso-octanol (2-ethylhexanol), was studied. The composition of the octanols and their solubility in various aqueous solutions were evaluated. The capacity of the octanols for tantalum(V) and niobium(V), the extraction properties of the octanols, the viscosity of extracts under conditions of metal fluoride extraction, and the temperature dependence of the viscosity of the octanols were studied. The composition of the extracted complexes was studied by IR and NMR spectroscopy and chemical analysis, and the hydration-solvation mechanism of the extraction of tantalum(V) and niobium(V) was supported [ru

  5. Mechanical properties of ion-implanted alumina

    International Nuclear Information System (INIS)

    Pope, S.G.

    1988-01-01

    Monolithic oxide ceramics are being proposed as structural materials in continuously more-demanding applications. The demands being placed on these materials have caused concern pertaining to the continued growth of oxide structural ceramics due to limited toughness. The realization that ceramic strength and toughness can be affected by surface conditions has led to many surface-modification techniques, all striving to improve the mechanical properties of ceramics. Along these lines, the effects of ion implantation as a surface modification technique for improvement of the mechanical properties of alumina were studied. Initially, sapphire samples were implanted with elemental ion species that would produce oxide precipitates within the sapphire surface when annealed in an oxygen-containing atmosphere. Optimum conditions as determined from implantation into sapphire were then used to modify a polycrystalline alumina. Specific modifications in microhardness, indentation fracture toughness and flexure strength are reported for the parameters studied. Microstructure and phase relationships related to modified surfaces properties are also reported

  6. Effect of special environmental factors exerted on mechanical properties of CFRP

    International Nuclear Information System (INIS)

    Sonoda, Katsumi; Kaneda, Yoshiharu; Tani, Isao; Nakazaki, Koichi; Enomoto, Junzo; Murayama, Kunihiko; Nakano, Norihiko; Hasegawa, Sumiko; Fukuta, Kenji

    1984-01-01

    This research aims at clarifying the behavior of deterioration of composite materials in the special environment of single factor or compound factors, examining the similarity of the acceleration of deterioration to actual environment and extracting the singularity, and establishing the method of evaluating the properties to withstand environmental effect. In this study, the test on the exposure to various special environments, such as thermal shock, low temperature-high temperature cycle fatigue, electron beam irradiation and heat and vacuum, was carried out. An Instron type testing machine was used, and measurement was carried out at room temperature. The results of the examination of the change of properties due to the change of testing condition by thermal shock test, the electron beam irradiation test at 7.5 x 10 8 rad/h, and the examination of the degasing from CFRP by heat and vacuum test are reported. It was found that bending stress loading method was effective as an accelerated test method because the lowering of residual bending fracture strength was accelerated by thermal shock test. The mechanical properties of CFRP did not change by electron beam irradiation up to 5000 Mrad. The degasing from CFRP under heat and vacuum increased with rising temperature. (Kako, I.)

  7. Mechanical properties of porous silicon by depth-sensing nanoindentation techniques

    International Nuclear Information System (INIS)

    Fang Zhenqian; Hu Ming; Zhang Wei; Zhang Xurui; Yang Haibo

    2009-01-01

    Porous silicon (PS) was prepared using the electrochemical corrosion method. Thermal oxidation of the as-prepared PS samples was performed at different temperatures for tuning their mechanical properties. The mechanical properties of as-prepared and oxidized PS were thoroughly investigated by depth-sensing nanoindentation techniques with the continuous stiffness measurements option. The morphology of as-prepared and oxidized PS was characterized by field emission scanning electron microscope and the effect of observed microstructure changes on the mechanical properties was discussed. It is shown that the hardness and Young's elastic modulus of as-prepared PS exhibit a strong dependence on the preparing conditions and decrease with increasing current density. In particular, the mechanical properties of oxidized PS are improved greatly compared with that of as-prepared ones and increase with increasing thermal oxidation temperature. The mechanism responsible for the mechanical property enhancement is possibly the formation of SiO 2 cladding layers encapsulating on the inner surface of the incompact sponge PS to decrease the porosity and strengthen the interconnected microstructure

  8. Mechanical properties of brain tissue by indentation : interregional variation

    NARCIS (Netherlands)

    Dommelen, van J.A.W.; Sande, van der T.P.J.; Hrapko, M.; Peters, G.W.M.

    2010-01-01

    Although many studies on the mechanical properties of brain tissue exist, some controversy concerning the possible differences in mechanical properties of white and gray matter tissue remains. Indentation experiments are conducted on white and gray matter tissue of various regions of the cerebrum

  9. Immunostimulatory properties of mistletoe extracts and their application in oncology

    Directory of Open Access Journals (Sweden)

    Sylwia Wrotek

    2014-10-01

    Full Text Available For a long time cancer immunotherapy was overshadowed by chemotherapy and radiotherapy. Recently, “Science”, one of the world’s top scientific journals, named the stimulation of the body’s own immune system to fight cancer cells as the “breakthrough of the year”. In Germany, Switzerland and Austria, extracts derived from mistletoe (Viscum album L. such as Iscador, Abnobaviscum, Helixor, Iscar, Iscucin and Isorel have been used in oncology for many years. These extracts have immunomodulating and immunostimulating properties, as demonstrated by experimental studies as well as in clinical trials. The aim of our paper is to present immunological disorders associated with cancer, which can be counteracted by treatment with extracts derived from mistletoe. Although these drugs cannot replace conventionalcancer treatment, they may improve the patient’s quality and length of life.

  10. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Hadryś D.

    2016-12-01

    Full Text Available New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF in weld metal deposit (WMD is obtained in MIG welding method with micro-jet cooling in relation to ordinary MIG welding method. This article presents the influence of the cooling medium and the number of micro-jet streams on mechanical properties of the welded joint. Mechanical properties were described by force which is necessary to destroy weld joint.

  11. Mechanical properties and morphology of poly(etheretherKetone)

    Science.gov (United States)

    Cebe, Peggy; Chung, Shirley; Gupta, Amitava; Hong, Su-Don

    1987-01-01

    Mechanical properties and morphology of poly(etheretherketone) (PEEK) were studied for samples having different thermal histories. Isothermal and rate-dependent crystallization were studied to ascertain the relationship between crystallinity/morphology and processing condition. Degree of crystallinity and microstructure were controlled by cooling the melt at different rates, ranging from quenching to slowly cooling, and by annealing amorphous material above the glass transition temperature Tg. It is found that degree of crystallinity was not as important as processing history in determining the room temperature mechanical properties. Samples with the same degree of crystallinity had very different tensile properties, depending on rate of cooling from the melt. All samples yielded by shear band formation and necked down. Quenched films had the largest breaking strains, drawing to 270 percent. Slowly cooled films exhibited ductile failure at relatively low strains. Best combined mechanical properties were obtained from semicrystalline films cooled at intermediate rates from the melt.

  12. Optimization of the cooling circuit and thermo-mechanical analysis for the extraction grid of ELISE

    International Nuclear Information System (INIS)

    Nocentini, R.; Gutser, R.; Heinemann, B.; Froeschle, M.; Riedl, R.

    2011-01-01

    The NNBI test facility ELISE ('Extraction from a Large Ion Source Experiment'), presently under construction at IPP, will have an extraction area with the same width and half the height of the ITER source, acceleration up to 60 kV, for 10 s, every 180 s, and plasma generation up to 1 h. Electrons are co-extracted from the ion source. Suppression magnets in the extraction grid deflect the electrons onto the extraction grid surface. For 30 mA/cm 2 extracted electron current density and 10 kV extraction voltage, localized power density is in the order of 39 MW/m 2 near the grid apertures and a total heat load of 150 kW is deposited onto each extraction grid segment. Heat removal is provided by a water circuit inside the grid. For ELISE, a new cooling circuit has been developed to provide a more reliable operation. The optimization of the cooling circuit and the thermo-mechanical analysis of the extraction grid of ELISE, considering maximum grid temperature, mechanical stresses and grid deformation, has been performed using the codes KOBRA3, TrajAn, the ANSYS finite element package and the fluid dynamics code CFX.

  13. AISI/DOE Advanced Process Control Program Vol. 4 of 6: ON-LINE, NON-DESTRUCTIVE MECHANICAL PROPERTY MEASUREMENT USING LASER-ULTRASOUND

    Energy Technology Data Exchange (ETDEWEB)

    Andre' Moreau; Martin Lord; Daniel Levesqure; Marc Dubois; Jean Bussiere; Jean-Pierre Monchalin; Christian Padioleau; Guy Lamouche; Teodor Veres; Martin Viens; Harold Hebert; Pierre Basseras; Cheng-Kuei Jen

    2001-03-31

    The goal of this project was to demonstrate the feasibility to measure the mechanical properties, such as yield strength, tensile strength, elongation, strain hardening exponent and plastic strain ratio parameters, of low carbon steel sheets on the production line using laser ultrasound. The ultrasound generated by the developed apparatus travels mostly back and forth in the thickness of the steel sheet. By measuring the time delay between two echoes, and the relative amplitude of these two echoes, one can measure ultrasound velocity and attenuation. These are governed by the microstructure: grain size, crystallographic texture, dislocations, etc. Thus, by recording the time behavior of the ultrasonic signal, one can extract microstructural information. These microstructural information together with the modified Hall-Petch equation allow measurement of the mechanical properties. Through laboratory investigations with a laboratory laser ultrasound system, followed by the installation of a prototype system at LTV Steel Company's No.1 Inspection Line in Cleveland, all target mechanical properties of ultra low carbon (ULC), low carbon (LC) and high strength low alloy (HSLA) steel sample lots were measured meeting or nearly meeting all the target accuracies. Thus, the project realized its goal to demonstrate that the mechanical properties of low carbon steel sheets can be measured on-line using laser ultrasound

  14. Mechanical Properties of Austenitic Stainless Steel Made by Additive Manufacturing.

    Science.gov (United States)

    Luecke, William E; Slotwinski, John A

    2014-01-01

    Using uniaxial tensile and hardness testing, we evaluated the variability and anisotropy of the mechanical properties of an austenitic stainless steel, UNS S17400, manufactured by an additive process, selective laser melting. Like wrought materials, the mechanical properties depend on the orientation introduced by the processing. The recommended stress-relief heat treatment increases the tensile strength, reduces the yield strength, and decreases the extent of the discontinuous yielding. The mechanical properties, assessed by hardness, are very uniform across the build plate, but the stress-relief heat treatment introduced a small non-uniformity that had no correlation to position on the build plate. Analysis of the mechanical property behavior resulted in four conclusions. (1) The within-build and build-to-build tensile properties of the UNS S17400 stainless steel are less repeatable than mature engineering structural alloys, but similar to other structural alloys made by additive manufacturing. (2) The anisotropy of the mechanical properties of the UNS S17400 material of this study is larger than that of mature structural alloys, but is similar to other structural alloys made by additive manufacturing. (3) The tensile mechanical properties of the UNS S17400 material fabricated by selective laser melting are very different from those of wrought, heat-treated 17-4PH stainless steel. (4) The large discontinuous yielding strain in all tests resulted from the formation and propagation of Lüders bands.

  15. Statistical properties of compartmental model parameters extracted from dynamic positron emission tomography experiments

    International Nuclear Information System (INIS)

    Mazoyer, B.M.; Huesman, R.H.; Budinger, T.F.; Knittel, B.L.

    1986-01-01

    Over the past years a major focus of research in physiologic studies employing tracers has been the computer implementation of mathematical methods of kinetic modeling for extracting the desired physiological parameters from tomographically derived data. A study is reported of factors that affect the statistical properties of compartmental model parameters extracted from dynamic positron emission tomography (PET) experiments

  16. Ultrasound-based testing of tendon mechanical properties

    DEFF Research Database (Denmark)

    Seynnes, O R; Bojsen-Møller, J.; Albracht, K

    2015-01-01

    In the past 20 years, the use of ultrasound-based methods has become a standard approach to measure tendon mechanical properties in vivo. Yet the multitude of methodological approaches adopted by various research groups probably contribute to the large variability of reported values. The technique......, or signal synchronization; and 2) in physiological considerations related to the viscoelastic behavior or length measurements of tendons. Hence, the purpose of the present review is to assess and discuss the physiological and technical aspects connected to in vivo testing of tendon mechanical properties...

  17. Mechanical Properties of Picea sitchensis

    DEFF Research Database (Denmark)

    Bräuner, Lise; Hoffmeyer, Preben; Poulsson, Lise

    2000-01-01

    the requirements at the same level as Danish grown Norway spruce. The study shows that Sitka spruce and Norway spruce of the same origin exhibit highly comparable mechanical properties. Key words: annual ring width, bending strength, characteristic strength, dry density, EN 338, INSTA 142, modulus of elasticity...

  18. Mechanical Properties of Stable Glasses Using Nanoindentation

    Science.gov (United States)

    Wolf, Sarah; Liu, Tianyi; Jiang, Yijie; Ablajan, Keyume; Zhang, Yue; Walsh, Patrick; Turner, Kevin; Fakhraai, Zahra

    Glasses with enhanced stability over ordinary, liquid quenched glasses have been formed via the process of Physical Vapor Deposition (PVD) by using a sufficiently slow deposition rate and a substrate temperature slightly below the glass transition temperature. These stable glasses have been shown to exhibit higher density, lower enthalpy, and better kinetic stability over ordinary glass, and are typically optically birefringent, due to packing and orientational anisotropy. Given these exceptional properties, it is of interest to further investigate how the properties of stable glasses compare to those of ordinary glass. In particular, the mechanical properties of stable glasses remain relatively under-investigated. While the speed of sound and elastic moduli have been shown to increase with increased stability, little is known about their hardness and fracture toughness compared to ordinary glasses. In this study, glasses of 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene were deposited at varying temperatures relative to their glass transition temperature, and their mechanical properties measured by nanoindentation. Hardness and elastic modulus of the glasses were compared across substrate temperatures. After indentation, the topography of these films were studied using Atomic Force Microscopy (AFM) in order to further compare the relationship between thermodynamic and kinetic stability and mechanical failure. Z.F. and P.W. acknowledge funding from NSF(DMREF-1628407).

  19. A study on thermal and mechanical properties of mechanically milled HDPE and PP

    International Nuclear Information System (INIS)

    Can, S.; Tan, S.

    2003-01-01

    In this study, mechanical mixing of HDPE and PP was performed via ball milling. Prepared compositions were 75/25 , 50/50 , 25/75 w/w HDPE/PP. Milling time and ball to powder ratio (B/P) were kept constant and system was cooled by adding solid CO 2 to improve the milling efficiency. To compare these systems with traditional methods, mixtures were also melt mixed by Brabender Plasti-Corder. Both milled and melt mixed systems were examined with DSC for thermal properties and tensile testing for mechanical properties Results are discussed by comparing milled , melt mixed and as-received polymers. It is observed that, unlike ball milled systems' in melt mixed systems mechanical properties are composition dependent. In addition , ball milling results in amorphization of both polymers and very high amounts of PP (75wt %) creates very amorphous HDPE structure. (Original)

  20. Radioprotective property of the ethanolic extract of Piper betel leaf

    International Nuclear Information System (INIS)

    Bhattacharya, S.; Roychowdhury, S.; Bandyopadhyay, S.K.; Subramanian, M.; Bauri, A.K.; Chattopadhyay, S.; Kamat, J.P.

    2005-01-01

    The radioprotective activity of Piper betel ethanolic extract (PE) has been studied using rat liver mitochondria and pBR 322 plasmid DNA as two model in vitro systems. The extract effectively prevented γ-ray induced lipid peroxidation as assessed by measuring thiobarbituric acid reactive substrates, lipid hydroperoxide and conjugated diene. Likewise, it prevented radiation-induced DNA strand breaks in a concentration dependent manner. The radioprotective activity of PE could be attributed to its hydroxyl and superoxide radicals scavenging property along with its lymphoproliferative activity. The radical scavenging capacity of PE was primarily due to its constituent phenolics, which were isolated and identified as chevibetol and allyl pyrocatechol. (author)

  1. Enhancement the Thermal Stability and the Mechanical Properties of Acrylonitrile-Butadiene Copolymer by Grafting Antioxidant

    Directory of Open Access Journals (Sweden)

    Abdulaziz Ibrahim Al-Ghonamy

    2010-01-01

    Full Text Available Monomeric antioxidants are widely used as effective antioxidants to protect polymers against thermal oxidation. Low molecular weight antioxidants are easily lost from polymer through migration, evaporation, and extraction. Physical loss of antioxidants is considered to be major concern in the environmental issues and safety regulation as well as long life time of polymers. The grafting copolymerization of natural rubber and o-aminophenol was carried out by using two-roll mill machine. The prepared natural rubber-graft-o-Aminophenol, NR-graft-o-AP, was analysed by using Infrared and 1H-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizates containing the commercial antioxidant, N-phenyl--naphthylamine (PBN, the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanizate. Results of the thermal stability showed that the prepared NR-graft-o-AP can protect NBR vulcanizate against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanizate.

  2. Enhancement the Thermal Stability and the Mechanical Properties of Acrylonitrile-Butadiene Copolymer by Grafting Antioxidant

    International Nuclear Information System (INIS)

    Al-Ghonamy, A.I.; El-Wakil, A.A.; Ramadan, M.; El-Wakil, A.A.; Ramadan, M.

    2010-01-01

    Monomeric antioxidants are widely used as effective antioxidants to protect polymers against thermal oxidation. Low molecular weight antioxidants are easily lost from polymer through migration, evaporation, and extraction. Physical loss of antioxidants is considered to be major concern in the environmental issues and safety regulation as well as long life time of polymers. The grafting copolymerization of natural rubber and o-aminophenol was carried out by using two-roll mill machine. The prepared natural rubber-graft-o-Aminophenol, NR-graft-o-AP, was analysed by using Infrared and 1H-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizations containing the commercial antioxidant, N-phenyl-β-naphthylamine (PBN), the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanization. Results of the thermal stability showed that the prepared NR-graft-o-AP can protect NBR vulcanization against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanization.

  3. Insecticidal and Repellent Properties of Subtropical Plant Extracts Against Pulse Beetle, Callosobruchus chinensis

    Directory of Open Access Journals (Sweden)

    H.T. AI Lawati

    2002-01-01

    Full Text Available Extracts of eight plants local to Oman, namely Qarat (Acacia nilotica, Mustafal (Annona squamosa, Shereesh (Azadirachta indica, Luban (Boswellia sacra, Kheshkhash (Crotolaria juncea, Zebrot (Jatropha dhofarica Yas, (Myrtus communis and Suwwad (Suaeda aegyptiaca were prepared by steeping shaded dried leaf/ seed powder of each plant in water and solvent (methanol or ethanol. The extracts were tested for their insecticidal and repellent properties against the pulse beetles, Callosobruchus chinensis. The extracts from the seeds of A. squamosa recorded l00% mortality of beetles within twenty and four hours of their exposure to methanol and ethanol extracts, respectively. The other extracts that caused high mortality were from A. nilotica, C. juncea, M. communis and S. aegzptiaca in methanol and B. sacra, J. dhofarica, S. aegptiaca and commercial neem in ethanol. Extracts of M. communis in methanol were highly repellent to the beetles compared to other extracts. Legume seeds treated with extracts of A. squamosa were not repellent, rather the beetles were attracted to them.

  4. Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Jessica I. Lozano-Navarro

    2018-01-01

    Full Text Available The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate; betalains (from beetroot and pitaya; resveratrol (from grape; and thymol and carvacrol (from oregano were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications.

  5. Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

    Science.gov (United States)

    Díaz-Zavala, Nancy P.; Melo-Banda, José A.; García-Alamilla, Ricardo; Martínez-Hernández, Ana L.; Zapién-Castillo, Samuel

    2018-01-01

    The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate); betalains (from beetroot and pitaya); resveratrol (from grape); and thymol and carvacrol (from oregano) were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications. PMID:29329275

  6. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  7. Response of mechanical properties of glasses to their chemical, thermal and mechanical histories

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    , surface, thermal history or excess entropy of the final glass state. Here I review recent progresses in understanding of the responses of mechanical properties of oxide glasses to the compositional variation, thermal history and mechanical deformation. The tensile strength, elastic modulus and hardness...... of glass fibers are dependent on the thermal history (measured as fictive temperature), tension, chemical composition and redox state. However, the fictive temperature affects the hardness of bulk glass in a complicated manner, i.e., the effect does not exhibit a clear regularity in the range...... and micro-cracks occurring during indentation of a glass is discussed briefly. Finally I describe the future perspectives and challenges in understanding responses of mechanical properties of oxide glasses to compositional variation, thermal history and mechanical deformation....

  8. Study of mechanical properties of films of nanocomposites LLDPE/bentonite

    International Nuclear Information System (INIS)

    Silva, Eduardo M.; Carvalho, Laura H.; Canedo, Eduardo L.; Coutinho, Maria G.F.; Costa, Raquel B.; Araujo, Arthur R.A.

    2011-01-01

    Mechanical properties of LLDPE/bentonite clay were determined as a function of clay content (1 and 2% w/w), purification and organophilization. Raw materials were characterized by FTIR and XRD. Nanocomposites were obtained as flat films and characterized by XRD and mechanical properties. Results indicate that best overall mechanical properties were displayed by systems containing purified clay and that they tended to decrease with increasing clay content. Organofilization was effective and only intercalated nanocomposites were obtained. (author)

  9. Rock mass mechanical property estimations for the Yucca Mountain Site Characterization Project

    International Nuclear Information System (INIS)

    Lin, M.; Hardy, M.P.; Bauer, S.J.

    1993-06-01

    Rock mass mechanical properties are important in the design of drifts and ramps. These properties are used in evaluations of the impacts of thermomechanical loading of potential host rock within the Yucca Mountain Site Characterization Project. Representative intact rock and joint mechanical properties were selected for welded and nonwelded tuffs from the currently available data sources. Rock mass qualities were then estimated using both the Norwegian Geotechnical Institute (Q) and Geomechanics Rating (RMR) systems. Rock mass mechanical properties were developed based on estimates of rock mass quality, the current knowledge of intact properties, and fracture/joint characteristics. Empirical relationships developed to correlate the rock mass quality indices and the rock mass mechanical properties were then used to estimate the range of rock mass mechanical properties

  10. Determination of some mechanical properties of Ugu seed ( Telfairia ...

    African Journals Online (AJOL)

    products. Before the oil can be extracted, it has to pass through some processes like depoding, size reduction, cracking etc. The parameters needed in form of engineering properties of the seed to design and construct the processing, storage and ...

  11. Effect of hydrocarbon chain length of aliphatic diluents on hydrodynamic properties of irradiated solutions of extractant

    International Nuclear Information System (INIS)

    Gumenyuk, V.E.; Pribush, A.G.; Egorov, G.F.

    1990-01-01

    To optimize the composition of n-paraffin mixtures with different molecular weight, used as a diluent (D) of extractant during extraction reprocessing of spent fuel, interrelation between D hydrocarbon chain length and change in hydrodynamic properties of extraction mixture on D basis depending on the dose has been considered. It is shown that the value of threshold dose loading (D crit ), at which a sharp change in hydrodynamic properties of tri-n-butyl phosphate solutions in D is observed, decreases with hydrocarbon chain length growth. Empiric ratio relating D crit value and the number of carbon atoms of D is obtained

  12. Study on analgesic and anti-inflammatory properties of Cordia myxa fruit hydro-alcoholic extract.

    Science.gov (United States)

    Ranjbar, Mohammadmehdi; Varzi, Hossein Najafzadeh; Sabbagh, Atefeh; Bolooki, Adeleh; Sazmand, Alireza

    2013-12-15

    Cordia myxa is a plant which is used in tropical regions of the world. Analgesic and anti-inflammatory effect of fruit of this medicinal plant was investigated in mice. Hydro-alcoholic extract of it was prepared by maceration method. Formalin test was conducted in six groups of mice (6 animals in each group) and acetic acid test in another six groups (6 mice). Groups one to six in each test were administered normal saline, oral indomethacin, intraperitoneal tramadol, 100 mg kg(-1) oral extract, 200 mg kg(-1) oral extract and 100 mg kg(-1) intraperitoneal extract, respectively. The duration of foot lickings were calculated in formalin- administered (1st) group within min 0 to 5 (acute phase) and 15 to 25 (chronic phase). Acetic acid-induced writhings were counted within 10 min in the 2nd group. The results showed that hydro-alcoholic extract of Cordia myxa fruit was considerably effective in formalin test. Also, analgesic and anti-inflammatory properties of this plant's fruit in both acute and chronic phase are somewhat similar to these properties in the study on animal model of experimental colitis.

  13. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    International Nuclear Information System (INIS)

    Pérez Daroca, D.; Jaroszewicz, S.; Llois, A.M.; Mosca, H.O.

    2013-01-01

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement

  14. Phonon spectrum, mechanical and thermophysical properties of thorium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Daroca, D., E-mail: pdaroca@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Jaroszewicz, S. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina); Llois, A.M. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Consejo Nacional de Investigaciones Cientı´ficas y Técnicas (Argentina); Mosca, H.O. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Instituto de Tecnología Jorge A. Sabato, UNSAM-CNEA (Argentina)

    2013-06-15

    In this work, we study, by means of density functional perturbation theory and the pseudopotential method, mechanical and thermophysical properties of thorium carbide. These properties are derived from the lattice dynamics in the quasi-harmonic approximation. The phonon spectrum of ThC presented in this article, to the best authors’ knowledge, have not been studied, neither experimentally, nor theoretically. We compare mechanical properties, volume thermal expansion and molar specific capacities with previous results and find a very good agreement.

  15. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt. PMID:27499669

  16. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts.

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt.

  17. Bone density does not reflect mechanical properties in early-stage arthrosis

    DEFF Research Database (Denmark)

    Ding, Ming; Danielsen, CC; Hvid, I

    2001-01-01

    : medial arthrosis, lateral control, normal medial and normal lateral controls. The specimens were tested in compression to determine mechanical properties and then physical/compositional properties. Compared to the normal medial control, we found reductions in ultimate stress, Young's modulus, and failure...... cancellous bone and the 3 controls. None of the mechanical properties of arthrotic cancellous bone could be predicted by the physical/compositional properties measured. The increase in bone tissue in early-stage arthrotic cancellous bone did not make up for the loss of mechanical properties, which suggests...

  18. A review of extractions of seaweed hydrocolloids: Properties and applications

    Directory of Open Access Journals (Sweden)

    H. P. S. Abdul Khalil

    2018-04-01

    Full Text Available The term hydrocolloid generally refers to substances that form gels or provide viscous dispersion in the presence of water. Alginate, agar, and carrageenan are three commercially valuable hydrocolloids derived from certain brown and red seaweed and each has their distinct physicochemical properties (i.e. functional and bioactive. Various applications of these seaweed hydrocolloids as thickeners, stabilizers, coagulants and salves (in the wound and burn dressings and materials to produce bio-medical impressions in the food, pharmaceutical, and biotechnology industries are highlighted in this review. Although the existing industrial methods of extraction for these seaweed hydrocolloids are well-established, still growing demand has exposed certain limitations of those methods, notably efficiency and product consistency. In order to achieve targeted hydrocolloids for specific purposes and functionalities, some novel and green extraction methods have also been proposed and discussed. Microwave-assisted extraction (MAE, ultrasound-assisted extraction (UAE, enzyme-assisted extraction (EAE, supercritical fluid extraction (SFE, pressurized solvent extractions (PSE, reactive extrusion and photobleaching process are selectively presented as highly promising candidates that can avoid the use of chemicals and provide novel means of access to seaweed hydrocolloids with both economic and environmental benefits. However, this review does not provide the ‘best’ method or procedure as many are still under development. Hence, the review gives ‘food for thought’as to new processes which might be adopted industrially and concluded that further research is required in order to contribute additional new knowledge and refinement to this field of study.

  19. Antioxidant and antimicrobial properties of ethanolic extracts of guarana, boldo, rosemary and cinnamon

    Directory of Open Access Journals (Sweden)

    Jeannine Bonilla

    2017-06-01

    Full Text Available Abstract In this investigation, the ethanolic extracts of two less known plants, little reported in the literature (guarana and boldo leaves were studied in comparison with the ethanolic extracts of two well studied plants (cinnamon and rosemary, regarding their colour, GC-MS profile, phenolic content and their antioxidant and antimicrobial properties. The rosemary (59.20 ± 0.28 and guarana (56.63 ± 0.54 extracts showed the highest values for luminosity (L* and the UV-Vis absorption increased when L* decreased. GC-MS identified a limited number of compounds in the cinnamon and guarana extracts. The cinnamon extract showed the highest value for the total phenolic content (172 mg GA/g extract as compared to the other extracts. The highest antioxidant capacity was observed for the boldo leaves extract in the TEAC (6.66 ± 0.17 mM assay and for the rosemary extract in the DPPH (0.80 ± 0.14 mg/L test. In addition, all the extracts showed antimicrobial activity against the S. aureus strain, indicating that all the extracts studied could be used by food industries to develop new active food packaging materials.

  20. Mechanical properties of intra-ocular lenses

    Science.gov (United States)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  1. Understanding extractive bleed : wood extractives: distribution, properties, and classes

    Science.gov (United States)

    Edward Burke; Norm Slavik; Tony Bonura; Dennis Connelly; Tom Faris; Arnie Nebelsick; Brent Stuart; Sam Williams; Alex C. Wiedenhoeft

    2010-01-01

    Color, odor, and natural durability of heartwood are characteristics imparted by a class of chemicals in wood known collectively extractives. Wood is converted by the tree from sapwood to heartwood by the deposition of extractives, typically many years after the growth ring undergoing this change was formed by the tree. Extractives are thus not a part of the wood...

  2. Mechanical properties of austenitic stainless steels in sodium

    International Nuclear Information System (INIS)

    Lloyd, G.J.

    1978-03-01

    A detailed review of the mechanical properties of austenitic stainless steels in liquid sodium is presented. Consideration has been given to the influence of the of the impurities in reactor sodium and metallurgical variables upon the stress rupture life, the low cycle fatigue and combined creep/fatigue resistance, elastic-plastic crack propagation rates, the high cycle fatigue life, tensile properties and fracture toughness. The effects of exposure to contaminated sodium prior to testing are also discussed. Examples of the success of mechanistic interpretations of materials behaviour in sodium are given and additionally, the extent to which mechanical properties in sodium may be predicted with the use of appropriate data. (author)

  3. The Mechanical Properties of Recycled Polyethylene-Polyethylene Terephthalate Composites

    Directory of Open Access Journals (Sweden)

    Ehsan Avazverdi

    2015-02-01

    Full Text Available Polyethylene terephthalate (PET, one of the thermoplastic polymers, is encountered with arduous problems in its recycling. After recycling, its mechanical properties drop dramatically and therefore it cannot be used to produce the products as virgin PET does. Polyethylene is a thermoplastic polymer which can be easily recycled using the conventional recycling processes. The decreased mechanical properties of virgin polyethylene due to the environmental factors can be improved by reinforcing fillers. In this paper, we studied the effects of adding recycled polyethylene terephthalate (rPET as a filler, in various amounts with different sizes, on the physical and mechanical properties of recycled polyethylene. Composite samples were prepared using an internal mixer at temperature 185°C, well below rPET melting point (250°C, and characterized by their mechanical properties. To improve the compatibility between different components, PE grafted with maleic anhydride was added as a coupling agent in all the compositions under study. The mechanical properties of the prepared samples were performed using the tensile strength, impact strength, surface hardness and melt flow index (MFI tests. To check the dispersity of the polyethylene terephthalate powder in the polyethylene matrix, light microscopy was used. The results showed that the addition of rPET improved the tensile energy, tensile modulus and surface hardness of the composites while reduced the melt flow index, elongation-at-yield, tensile strength and fracture energy of impact test. We could conclude that with increasing rPET percentage in the recycled polyethylene matrix, the composite became brittle, in other words it decreased the plastic behavior of recycled polyethylene. Decreasing particle size led to higher surface contacts, increased the mechanical properties and made the composite more brittle. The light microscopy micrographs of the samples showed a good distribution of small r

  4. Microstructure and mechanical properties of laser treated aluminium alloys

    NARCIS (Netherlands)

    deHosson, JTM; vanOtterloo, LDM; Noordhuis, J; Mazumder, J; Conde, O; Villar, R; Steen, W

    1996-01-01

    Al-Cu alloys and an Al-Cu-Mg alloy, Al 2024-T3, were exposed to laser treatments at various scan velocities. In this paper the microstructural features and mechanical properties are reported. As far as the mechanical property of the Al-Cu-Mg alloy is concerned a striking observation is a minimum in

  5. Mechanical property estimation with ABI and FEM simulation

    International Nuclear Information System (INIS)

    Sharma, Kamal; Singh, P.K.; Das, Gautam; Bhasin, Vivek; Vaze, K.K.; Ghosh, A.K.

    2007-01-01

    A combined mechanical property evaluation methodology with ABI (Automated Ball Indentation) simulation and Artificial Neural Network (ANN) analysis is evolved to evaluate the mechanical properties for material. The experimental load deflection data is converted into meaningful mechanical properties for this material. An ANN database is generated with the help of contact type finite element analysis by numerically simulating the ABI process for various magnitudes of yield strength (σ yp ) (200 MPa - 500 MPa) with a range of strain hardening exponent (n) (0.1 - 0.5) and strength coefficient (K) (500 MPa - 1500 MPa). For the present problem, a ball indenter of 1.57 mm diameter having Young's modulus approximately 100 times more than the test piece is used to minimize the error due to indenter deformation. Test piece dimension is kept large enough in comparison to the indenter configuration in the simulation to minimize the deflection at the outer edge of the test piece. Further this database after the neural network training; is used to analyze measured material properties of different test pieces. The ANN predictions are reconfirmed with contact type finite element analysis for an arbitrary selected test sample. The methodology evolved in this work can be extended to predict material properties for any irradiated nuclear material in the service. (author)

  6. Maytenus erythroxylon Reissek (Celastraceae) ethanol extract presents antidiarrheal activity via antimotility and antisecretory mechanisms.

    Science.gov (United States)

    Formiga, Rodrigo de Oliveira; Quirino, Zelma Glebya Maciel; Diniz, Margareth de Fátima Formiga Melo; Marinho, Alexsandro Fernandes; Tavares, Josean Fechine; Batista, Leônia Maria

    2017-06-28

    To investigate the acute toxicity, phytochemical profile, antidiarrheal activity and mechanisms of action of Maytenus erythroxylon ( M. erythroxylon ) ethanol extract. A castor oil-induced diarrhea model was used to evaluate antidiarrheal activity. Intestinal transit and gastric emptying protocols were used to evaluate a possible antimotility effect. K ATP channels, nitric oxide, presynaptic α2-adrenergic and tissue adrenergic receptors were investigated to uncover antimotility mechanisms of action and castor oil-induced enteropooling to elucidate antisecretory mechanisms. All tested doses of the extract (62.5, 125, 250 and 500 mg/kg) possessed antidiarrheal activity, with a significant decrease of the evacuation index. This activity is possibly related to a reduced gastric emptying (125, 250 and 500 mg/kg) and to a decreased percentage of intestinal transit for all tested doses. That last effect seems to be modulated by nitric oxide, K ATP channels and tissue adrenergic receptors. Besides, the extract also presented antisecretory effect due to a decrease of intestinal fluid accumulation. The antidiarrheal effect of M. erythroxylon found in this study involves antimotility and antisecretory mechanisms that may be attributed to the chemical compounds found in this species: saponins, flavonoids, tannins, triterpenes and steroids.

  7. Maytenus erythroxylon Reissek (Celastraceae) ethanol extract presents antidiarrheal activity via antimotility and antisecretory mechanisms

    Science.gov (United States)

    Formiga, Rodrigo de Oliveira; Quirino, Zelma Glebya Maciel; Diniz, Margareth de Fátima Formiga Melo; Marinho, Alexsandro Fernandes; Tavares, Josean Fechine; Batista, Leônia Maria

    2017-01-01

    AIM To investigate the acute toxicity, phytochemical profile, antidiarrheal activity and mechanisms of action of Maytenus erythroxylon (M. erythroxylon) ethanol extract. METHODS A castor oil-induced diarrhea model was used to evaluate antidiarrheal activity. Intestinal transit and gastric emptying protocols were used to evaluate a possible antimotility effect. KATP channels, nitric oxide, presynaptic α2-adrenergic and tissue adrenergic receptors were investigated to uncover antimotility mechanisms of action and castor oil-induced enteropooling to elucidate antisecretory mechanisms. RESULTS All tested doses of the extract (62.5, 125, 250 and 500 mg/kg) possessed antidiarrheal activity, with a significant decrease of the evacuation index. This activity is possibly related to a reduced gastric emptying (125, 250 and 500 mg/kg) and to a decreased percentage of intestinal transit for all tested doses. That last effect seems to be modulated by nitric oxide, KATP channels and tissue adrenergic receptors. Besides, the extract also presented antisecretory effect due to a decrease of intestinal fluid accumulation. CONCLUSION The antidiarrheal effect of M. erythroxylon found in this study involves antimotility and antisecretory mechanisms that may be attributed to the chemical compounds found in this species: saponins, flavonoids, tannins, triterpenes and steroids. PMID:28706420

  8. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Directory of Open Access Journals (Sweden)

    Hudson Alves Silvério

    2014-12-01

    Full Text Available In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH30 on the mechanical, thermal, and barrier properties of methylcellulose (MC nanocomposites were evaluated. MC/WSH30 nanocomposite films with different filler levels (2, 4, 6, 8, and 10% were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH30, formation of a continuous network of WSH30 linked by hydrogen interactions and a close association between filler and matrix.

  9. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Silverio, Hudson Alves; Flauzino Neto, Wilson Pires; Silva, Ingrid Souza Vieira da; Rosa, Joyce Rover; Pasquini, Daniel, E-mail: pasquini@iqufu.ufu.br, E-mail: danielpasquini2005@yahoo.com.br [Universidade de Uberlandia (USU), MG (Brazil). Instituto de Quimica; Assuncao, Rosana Maria Nascimento de [Universidade de Uberlandia (USU), Ituiutaba, MG (brazil). Fac. de Ciencias Integradas do Pontal; Barud, Hernane da Silva; Ribeiro, Sidney Jose Lima [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

    2014-11-15

    In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH{sub 30}) on the mechanical, thermal, and barrier properties of methylcellulose (MC) nanocomposites were evaluated. MC/WSH{sub 30} nanocomposite films with different filler levels (2, 4, 6, 8, and 10%) were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH{sub 30}, formation of a continuous network of WSH{sub 30} linked by hydrogen interactions and a close association between filler and matrix. (author)

  10. Nucleus geometry and mechanical properties of resistance spot ...

    Indian Academy of Sciences (India)

    Keywords. Automotive steels; resistance spot welding; mechanical properties; nucleus geometry. 1. .... High va- lues of hardness can be explained with martensitic forma- ... interface of DP450–DP600 steels may have stainless steel properties.

  11. Mutual associations among microstructural, physical and mechanical properties of human cancellous bone

    DEFF Research Database (Denmark)

    Ding, Ming; Odgaard, A; Danielsen, CC

    2002-01-01

    structure and mechanical properties. In this study, 160 cancellous bone specimens were produced from 40 normal human tibiae aged from 16 to 85 years at post-mortem. The specimens underwent micro-CT and the microstructural properties were calculated using unbiased three-dimensional methods. The specimens...... were tested to determine the mechanical properties and the physical/compositional properties were evaluated. The type of structure together with anisotropy correlated well with Young's modulus of human tibial cancellous bone. The plate-like structure reflected high mechanical stress and the rod......-like structure low mechanical stress. There was a strong correlation between the type of trabecular structure and the bone-volume fraction. The most effective microstructural properties for predicting the mechanical properties of cancellous bone seem to differ with age....

  12. Multiscale simulation of mechanical properties of TiNb alloy

    Science.gov (United States)

    Nikonov, A. Yu.

    2017-12-01

    The article presents a numerical simulation of the mechanical properties of a Ti-Nb β-alloy on three different scales. The ab-initio approach is used to estimate the concentrations of the Ti alloy with required elastic properties. On the basis of molecular dynamics simulation, we calculate the adhesive force between individual particles of the alloy. The calculated dependence is implemented within the movable cellular automata method to determine the mechanical properties of Ti-Nb depending on the interparticle free space.

  13. A Novel Method of Mechanical Oxidation of CNT for Polymer Nanocomposite Application: Evaluation of Mechanical, Dynamic Mechanical, and Rheological Properties

    Directory of Open Access Journals (Sweden)

    Priyanka Pandey

    2014-01-01

    Full Text Available A new approach of oxidation of carbon nanotubes has been used to oxidize the CNTs. A comparative aspect of the mechanical oxidation and acid oxidation process has been established. FTIR analysis and titration method have shown the higher feasibility of the mechanical oxidation method to oxidize the CNTs. Comparatively less damage to the CNTs has been observed in case of mechanically oxidized as compared to acid oxidized CNTs. The mechanical properties of the nanocomposites reinforced with the acid oxidized CNT (ACNT and mechanically oxidized CNTs (McCNT were analyzed and relatively higher properties in the nanocomposites reinforced with McCNT were noticed. The less degree of entanglement in the McCNTs was noticed as compared to ACNTs. The dynamic mechanical analysis of the nanocomposites revealed much improved load transfer capability in the McCNT reinforced composites. Further, the rheological properties of the nanocomposites revealed the higher performance of McCNT reinforced composites.

  14. Determination of the mechanical properties of solid and cellular polymeric dosage forms by diametral compression.

    Science.gov (United States)

    Blaesi, Aron H; Saka, Nannaji

    2016-07-25

    At present, the immediate-release solid dosage forms, such as the oral tablets and capsules, are granular solids. They release drug rapidly and have adequate mechanical properties, but their manufacture is fraught with difficulties inherent in processing particulate matter. Such difficulties, however, could be overcome by liquid-based processing. Therefore, we have recently introduced polymeric cellular (i.e., highly porous) dosage forms prepared from a melt process. Experiments have shown that upon immersion in a dissolution medium, the cellular dosage forms with polyethylene glycol (PEG) as excipient and with predominantly open-cell topology disintegrate by exfoliation, thus enabling rapid drug release. If the volume fraction of voids of the open-cell structures is too large, however, their mechanical strength is adversely affected. At present, the common method for determining the tensile strength of brittle, solid dosage forms (such as select granular forms) is the diametral compression test. In this study, the theory of diametral compression is first refined to demonstrate that the relevant mechanical properties of ductile and cellular solids (i.e., the elastic modulus and the yield strength) can also be extracted from this test. Diametral compression experiments are then conducted on PEG-based solid and cellular dosage forms. It is found that the elastic modulus and yield strength of the open-cell structures are about an order of magnitude smaller than those of the non-porous solids, but still are substantially greater than the stiffness and strength requirements for handling the dosage forms manually. This work thus demonstrates that melt-processed polymeric cellular dosage forms that release drug rapidly can be designed and manufactured to have adequate mechanical properties. Copyright © 2016. Published by Elsevier B.V.

  15. Synthesis of Silver Nanoparticles Using Buchu Plant Extracts and Their Analgesic Properties

    Directory of Open Access Journals (Sweden)

    Herbert Chiguvare

    2016-06-01

    Full Text Available We herein report for the first time the synthesis and analgesic properties of silver nanoparticles (Ag-NPs using buchu plant extract. The as-synthesised Ag-NPs at different temperatures were characterised by UV-Vis spectroscopy, Fourier transform infra-red spectroscopy (FTIR and transmission transform microscopy (TEM to confirm the formation of silver nanoparticles. Phytochemical screening of the ethanolic extract revealed the presence of glycosides, proteins, tannins, alkaloids, flavonoids and saponins. The absorption spectra showed that the synthesis is temperature and time dependent. The TEM analysis showed that the as-synthesised Ag-NPs are polydispersed and spherical in shape with average particle diameter of 19.95 ± 7.76 nm while the FTIR results confirmed the reduction and capping of the as-synthesised Ag-NPs by the phytochemicals present in the ethanolic extract. The analgesic study indicated that the combined effect of the plant extract and Ag-NPs is more effective in pain management than both the aspirin drug and the extract alone.

  16. Region-specific mechanical properties of the human patella tendon

    DEFF Research Database (Denmark)

    Haraldsson, B T; Aagaard, P; Krogsgaard, M

    2004-01-01

    The present study investigated the mechanical properties of tendon fascicles from the anterior and posterior human patellar tendon. Collagen fascicles from the anterior and posterior human patellar tendon in healthy young men (mean +/- SD, 29.0 +/- 4.6 yr, n = 6) were tested in a mechanical rig...... portion of the tendon, indicating region-specific material properties....

  17. Rheological, thermo-mechanical, and baking properties of wheat-millet flour blends.

    Science.gov (United States)

    Aprodu, Iuliana; Banu, Iuliana

    2015-07-01

    Millet has long been known as a good source of fiber and antioxidants, but only lately started to be exploited by food scientists and food industry as a consequence of increased consumer awareness. In this study, doughs and breads were produced using millet flour in different ratios (10, 20, 30, 40, and 50%) to white, dark, and whole wheat flour. The flour blends were evaluated in terms of rheological and thermo-mechanical properties. Fundamental rheological measurements revealed that the viscosity of the flour formulations increases with wheat flour-extraction rate and decreases with the addition of millet flour. Doughs behavior during mixing, overmixing, pasting, and gelling was established using the Mixolab device. The results of this bread-making process simulation indicate that dough properties become critical for the flour blends with millet levels higher than 30%. The breads were evaluated for volume, texture, and crumb-grain characteristics. The baking test and sensory evaluation results indicated that substitution levels of up to 30% millet flour could be used in composite bread flour. High levels of millet flour (40 and 50%) negatively influenced the loaf volume, crumb texture, and taste. © The Author(s) 2014.

  18. Thermodynamics properties of complexation and extraction of LN(3) by diamides

    Energy Technology Data Exchange (ETDEWEB)

    Charbonnel, M.C.; Flandin, J.L.; Presson, M.T. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, DRRV, 30 - Marcoule (France); Morel, J.P. [Universite Blaise Pascal, Clermont-Ferrand II, Lab. de Chimie Physique des Solutions, (CNRS), 63 - Aubiere (France)

    2000-07-01

    In the frame of the French program SPIN, CEA has undertaken the development of the DIAMEX process which is the first step in the strategy of separation of minor actinides from fission products in High Level Waste. The extractant belongs to the diamide family and lead to a co-extraction actinides(III) - lanthanides(III). The study focuses on thermodynamic properties ({delta}H, {delta}G, {delta}S) related to the extraction of lanthanide elements by malonamide in order to have a better knowledge of the driven force and to explain some extraction differences between extractants. The main experimental technique used is the microcalorimetric titration whose principle will be detailed. Preliminary studies concern reactions of complexation Ln{sup 3+} - diamide in an homogeneous aqueous phase. We can assume that reaction is endothermic but some difficulties were encountered to obtain both K and {delta}H because of low complexation constants and small heats of reaction. Additional studies were carried out with spectroscopic methods (UV-Visible and LITRFS) to determine precise {delta}G{sub r} values. The variation in the lanthanide series was also studied. The main work deals with the thermodynamic constants of extraction for which both micro-calorimetry and classical Vant'Hoff approaches were studied: the results will be presented and discussed. (authors)

  19. Thermodynamics properties of complexation and extraction of LN(3) by diamides

    International Nuclear Information System (INIS)

    Charbonnel, M.C.; Flandin, J.L.; Presson, M.T.; Morel, J.P.

    2000-01-01

    In the frame of the French program SPIN, CEA has undertaken the development of the DIAMEX process which is the first step in the strategy of separation of minor actinides from fission products in High Level Waste. The extractant belongs to the diamide family and lead to a co-extraction actinides(III) - lanthanides(III). The study focuses on thermodynamic properties (ΔH, ΔG, ΔS) related to the extraction of lanthanide elements by malonamide in order to have a better knowledge of the driven force and to explain some extraction differences between extractants. The main experimental technique used is the microcalorimetric titration whose principle will be detailed. Preliminary studies concern reactions of complexation Ln 3+ - diamide in an homogeneous aqueous phase. We can assume that reaction is endothermic but some difficulties were encountered to obtain both K and ΔH because of low complexation constants and small heats of reaction. Additional studies were carried out with spectroscopic methods (UV-Visible and LITRFS) to determine precise ΔG r values. The variation in the lanthanide series was also studied. The main work deals with the thermodynamic constants of extraction for which both micro-calorimetry and classical Vant'Hoff approaches were studied: the results will be presented and discussed. (authors)

  20. Antioxidant, Anti-microbial Properties and Chemical Composition of Cumin Essential Oils Extracted by Three Methods

    Directory of Open Access Journals (Sweden)

    Fang Lianying

    2018-04-01

    Full Text Available The purpose of this study is to evaluate the chemical composition, antioxidant and anti-bacterial activity of cumin essential oils (CEOs extracted by different techniques, including supercritical carbon dioxide extraction (SCE, subcritical butane extraction (SBE and traditional solvent extraction (SE. Our results indicated that CEOs are a valuable source of bioactive compounds, including cumin aldehyde, γ-terpinene and β-pinene. The most abundant components found in CEOs obtained by SCE and SBE were similar, while the abundant components in SE, β-Cumic aldehyde (19.31% and α-phellandrene (9.49%, were distinctive. CEOs obtained by SCE exhibited higher antioxidant activity, followed by those extracted by SE and SBE. Moreover, the anti-microbial properties of CEOs obtained by SCE and SBE were higher than that of CEOs collected by SE. In conclusion, CEOs exhibit strong antioxidant and anti-microbial properties, which suggests a potential role of CEOs in preventing diseases associated with aging and oxidative stress, and our results highlight the potential usage of CEOs in the food industry.

  1. Measurement of material mechanical properties in microforming

    Science.gov (United States)

    Yun, Wang; Xu, Zhenying; Hui, Huang; Zhou, Jianzhong

    2006-02-01

    As the rapid market need of micro-electro-mechanical systems engineering gives it the wide development and application ranging from mobile phones to medical apparatus, the need of metal micro-parts is increasing gradually. Microforming technology challenges the plastic processing technology. The findings have shown that if the grain size of the specimen remains constant, the flow stress changes with the increasing miniaturization, and also the necking elongation and the uniform elongation etc. It is impossible to get the specimen material properties in conventional tensile test machine, especially in the high precision demand. Therefore, one new measurement method for getting the specimen material-mechanical property with high precision is initiated. With this method, coupled with the high speed of Charge Coupled Device (CCD) camera and high precision of Coordinate Measuring Machine (CMM), the elongation and tensile strain in the gauge length are obtained. The elongation, yield stress and other mechanical properties can be calculated from the relationship between the images and CCD camera movement. This measuring method can be extended into other experiments, such as the alignment of the tool and specimen, micro-drawing process.

  2. Characterization of Mechanical Properties of Microbial Biofilms

    Science.gov (United States)

    Callison, Elizabeth; Gose, James; Perlin, Marc; Ceccio, Steven

    2017-11-01

    The physical properties of microbial biofilms grown subject to shear flows determine the form and mechanical characteristics of the biofilm structure, and consequently, the turbulent interactions over and through the biofilm. These biofilms - sometimes referred to as slime - are comprised of microbial cells and extracellular polymeric substance (EPS) matrices that surround the multicellular communities. Some of the EPSs take the form of streamers that tend to oscillate in flows, causing increased turbulent mixing and drag. As the presence of EPS governs the compliance and overall stability of the filamentous streamers, investigation of the mechanical properties of biofilms may also inform efforts to understand hydrodynamic performance of fouled systems. In this study, a mixture of four diatom genera was grown under turbulent shear flow on test panels. The mechanical properties and hydrodynamic performance of the biofilm were investigated using rheology and turbulent flow studies in the Skin-Friction Flow Facility at the University of Michigan. The diatoms in the mixture of algae were identified, and the elastic and viscous moduli were determined from small-amplitude oscillations, while a creep test was used to evaluate the biofilm compliance.

  3. Research on working property and early age mechanical property of self-compacting concrete used in steel-concrete structure

    International Nuclear Information System (INIS)

    Zhao Yongguang

    2013-01-01

    Background: Self-compacting concrete that has good working property is the prerequisite of steel-concrete structure. The early age mechanical property of self-compacting concrete is the important parameter when design steel-concrete structure. Purpose: This paper attempts to research the working property and early age mechanical property of self-compacting concrete. Methods: Test is used to research the working property and early age mechanical property of self-compacting concrete. Results: Self-compacting concrete that could meet the requirement of steel-concrete structure has been mixed and parameters of early age mechanical property of self-compacting concrete which is necessary for design of steel-concrete structure have been presented. Conclusions: Base on the results, this paper can guide the construction of self-compacting concrete in steel-concrete structure and the design and construction of steel-concrete structure. (author)

  4. Mechanical and Thermal Properties of the AH of FRW Universe

    International Nuclear Information System (INIS)

    Yi-Huan, Wei

    2010-01-01

    We calculate the work made out by the apparent horizon (AH) of the Friedmann–Robertson–Walker (FRW) universe and the heat flux through the AH from the first law of thermodynamics. We discuss the mechanical properties of the AH and analyze the universe model for which the mechanical properties can change. Finally, the thermal properties of the AH of FRW universe are discussed

  5. Mechanisms of Action of Uncaria rhynchophylla Ethanolic Extract for Its Vasodilatory Effects.

    Science.gov (United States)

    Loh, Yean Chun; Ch'ng, Yung Sing; Tan, Chu Shan; Ahmad, Mariam; Asmawi, Mohd Zaini; Yam, Mun Fei

    2017-09-01

    Uncaria rhynchophylla is one of the major components included in Traditional Chinese Medicine prescriptions for hypertensive treatment. Previous studies have suggested that U. rhynchophylla might contain vasodilation-mediating active compounds, especially indole alkaloids. Hence, this study was carried out to determine the vasodilatory effects of U. rhynchophylla, which was extracted by different solvents. The most effective extract was then further studied for its signaling mechanism pathways. The authenticity of U. rhynchophylla was assured by using modernized tri-step Fourier transform infrared (FTIR), including conventional 1D FTIR, second derivative scanning combined with 2D-correlated IR spectroscopy. Results obtained proved that the fingerprint of U. rhynchophylla used was identical to the atlas. Isolated aortic rings from male Sprague-Dawley rats were preconstricted with phenylephrine (PE) followed by cumulative addition of U. rhynchophylla extracts. The signaling mechanism pathways were studied by incubation with different receptor antagonists before the PE precontraction. In conclusion, the 95% ethanolic U. rhynchophylla extract (GT100) was found to be most effective with an EC 50 value of 0.028 ± 0.002 mg/mL and an R max value of 101.30% ± 2.82%. The signaling mechanism pathways employed for exerting its vasodilatory effects included nitric oxide/soluble guanylyl cylcase/cyclic guanosine monophosphate (NO/sGC/cGMP) and PGI 2 (endothelium-derived relaxing factors), G protein-coupled M 3 - and β 2 receptors, regulation of membrane potential through voltage-operated calcium channel, intracellular Ca 2+ released from inositol triphosphate receptor (IP 3 R), and all potassium channels except the K ca channel.

  6. Investigation of Mechanical Properties and Interfacial Mechanics of Crystalline Nanomaterials

    Science.gov (United States)

    Qin, Qingquan

    Nanowires (NWs) and nanotubes (NTs) are critical building blocks of nanotechnologies. The operation and reliability of these nanomaterials based devices depend on their mechanical properties of the nanomaterials, which is therefore important to accurately measure the mechanical properties. Besides, the NW--substrate interfaces also play a critical role in both mechanical reliability and electrical performance of these nanodevices, especially when the size of the NW is small. In this thesis, we focus on the mechanical properties and interface mechanics of three important one dimensional (1D) nanomaterials: ZnO NWs, Ag NWs and Si NWs. For the size effect study, this thesis presents a systematic experimental investigation on the elastic and failure properties of ZnO NWs under different loading modes: tension and buckling. Both tensile modulus (from tension) and bending modulus (from buckling) were found to increase as the NW diameter decreased from 80 to 20 nm. The elastic modulus also shows loading mode dependent; the bending modulus increases more rapidly than the tensile modulus. The tension experiments showed that fracture strain and strength of ZnO NWs increase as the NW diameter decrease. A resonance testing setup was developed to measure elastic modulus of ZnO NWs to confirm the loading mode dependent effect. A systematic study was conducted on the effect of clamping on resonance frequency and thus measured Young's modulus of NWs via a combined experiment and simulation approach. A simple scaling law was provided as guidelines for future designs to accurate measure elastic modulus of a cantilevered NW using the resonance method. This thesis reports the first quantitative measurement of a full spectrum of mechanical properties of five-fold twinned Ag NWs including Young's modulus, yield strength and ultimate tensile strength. In situ tensile testing of Ag NWs with diameters between 34 and 130 nm was carried out inside a SEM. Young's modulus, yield strength and

  7. Effect of Punica granatum peel extracts on antimicrobial properties in Walnut shell cellulose reinforced Bio-thermoplastic starch films from cashew nut shells.

    Science.gov (United States)

    Harini, K; Chandra Mohan, C; Ramya, K; Karthikeyan, S; Sukumar, M

    2018-03-15

    The main aim of the present study is to extract and characterize cashew nut shell (CNS) starch and walnut shell cellulose (WNC) for development of cellulose reinforced starch films. Moreover, the extraction and characterization of pomegranate peel extract, for incorporation with CNS-WNC films, was investigated. CNS starch was examined to be a moderate amylose starch with 26.32 ± 0.43% amylose content. Thermal degradation temperature of CNS starch was found to be 310 °C. Walnut shell cellulose was found to have high crystallinity index of 72%, with two thermal degradation temperatures of 319 °C and 461 °C. 2% WN cellulose reinforced CNS starch films were examined to have good oxygen transfer rate, mechanical and physical properties. Thermal degradation temperature of CNS-WNC starch films were found to be at the range of 298-302 °C. Surface roughness of CNS-WNC starch films were found to be increasing with increase in concentration of cellulose in films. Hydroxymethylfurfurole, Benzene, 2-methoxy-1,3,4-trimethyl and 1,2,3-Propanetriol, 1-acetate were found to be major active compounds present in hydrophilic extracts of Punica granatum peels. 2% WN cellulose reinforced starch films infused with hydrophilic active compounds of pomegranate peel was examined to be having good active package properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Flow Cytometry Detection of Bacterial Cell Entrapment within the Chitosan Hydrogel and Antibacterial Property of Extracted Chitosan

    Directory of Open Access Journals (Sweden)

    Nafise Sadat Majidi

    2016-09-01

    Full Text Available Background:   Chitosan is unbranched polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine. Chitosan, derived from shrimp shell, has broad antimicrobial properties against Gram-negative, Gram-positive bacteria and fungi. Methods:  Chitosan was extracted from shrimp shell and studied for cell entrapment and anti-bacterial properties. The hydrogel chitosan was used as the beads for cell entrapment and chitosan beads were designed to deliver cells and nutrients. These data confirmed with flow cytometric analyses.                 Results:   Experimental results exhibited that internal diffusion through the chitosan matrix was the main mechanism for whole gelation by TPP (Tri-polyphosphate. The minimum inhibitory concentration (MIC for chitosan against Staphylococcus aureus and Escherichia coli was 16 and 32 μg/ml respectively. Conclusion:  Despite the antimicrobial properties of chitosan, trapped bacteria in the gel network were alive and were chelated indicating that their access to the outside was limited.

  9. [Studies on the mechanical properties of the knee ligament].

    Science.gov (United States)

    Kubotera, D

    1987-04-01

    To study mechanical properties of the knee ligaments, tension tests at various speeds were performed on the knee of a dog with only the collateral ligament. The results showed that the tensile force was greater in high speed than in low speed test. The difference may be caused in a viscous property of the ligament. The mechanical properties of ligaments can therefore be treated as those of viscoelastic materials and expressed by a modified Voigt model consisting of a non-linear spring element and a dash pot component. Observations regarding the ultrastructure of human knee ligaments using an electron scanning microscope revealed wavy bundles of collagen fiber connected with coarse fibers like network running in parallel with the long axis as the main structure. The above structure and properties were considered to be the decisive factors in the mechanical actions of the knee ligament.

  10. Integrated automated nanomanipulation and real-time cellular surface imaging for mechanical properties characterization

    Science.gov (United States)

    Eslami, Sohrab; Zareian, Ramin; Jalili, Nader

    2012-10-01

    Surface microscopy of individual biological cells is essential for determining the patterns of cell migration to study the tumor formation or metastasis. This paper presents a correlated and effective theoretical and experimental technique to automatically address the biophysical and mechanical properties and acquire live images of biological cells which are of interest in studying cancer. In the theoretical part, a distributed-parameters model as the comprehensive representation of the microcantilever is presented along with a model of the contact force as a function of the indentation depth and mechanical properties of the biological sample. Analysis of the transfer function of the whole system in the frequency domain is carried out to characterize the stiffness and damping coefficients of the sample. In the experimental section, unlike the conventional atomic force microscope techniques basically using the laser for determining the deflection of microcantilever's tip, a piezoresistive microcantilever serving as a force sensor is implemented to produce the appropriate voltage and measure the deflection of the microcantilever. A micromanipulator robotic system is integrated with the MATLAB® and programmed in such a way to automatically control the microcantilever mounted on the tip of the micromanipulator to achieve the topography of biological samples including the human corneal cells. For this purpose, the human primary corneal fibroblasts are extracted and adhered on a sterilized culture dish and prepared to attain their topographical image. The proposed methodology herein allows an approach to obtain 2D quality images of cells being comparatively cost effective and extendable to obtain 3D images of individual cells. The characterized mechanical properties of the human corneal cell are furthermore established by comparing and validating the phase shift of the theoretical and experimental results of the frequency response.

  11. Mechanical properties of the beetle elytron, a biological composite material

    Science.gov (United States)

    We determined the relationship between composition and mechanical properties of elytral (modified forewing) cuticle of the beetles Tribolium castaneum and Tenebrio molitor. Elytra of both species have similar mechanical properties at comparable stages of maturation (tanning). Shortly after adult ecl...

  12. Superconducting state mechanisms and properties

    CERN Document Server

    Kresin, Vladimir Z; Wolf, Stuart A

    2014-01-01

    'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

  13. Enhancement of mechanical properties of epoxy/graphene nanocomposite

    Science.gov (United States)

    Berhanuddin, N. I. C.; Zaman, I.; Rozlan, S. A. M.; Karim, M. A. A.; Manshoor, B.; Khalid, A.; Chan, S. W.; Meng, Q.

    2017-10-01

    Graphene is a novel class of nanofillers possessing outstanding characteristics including most compatible with most polymers, high absolute strength, high aspect ratio and cost effectiveness. In this study, graphene was used to reinforce epoxy as a matrix, to enhance its mechanical properties. Two types of epoxy composite were developed which are epoxy/graphene nanocomposite and epoxy/modified graphene nanocomposite. The fabrication of graphene was going through thermal expansion and sonication process. Chemical modification was only done for modified graphene where 4,4’-Methylene diphenyl diisocyanate (MDI) is used. The mechanical properties of both nanocomposite, such as Young’s modulus and maximum stress were investigated. Three weight percentage were used for this study which are 0.5 wt%, 1.0 wt% and 1.5 wt%. At 0.5 wt%, modified and unmodified shows the highest value compared to neat epoxy, where the value were 8 GPa, 6 GPa and 0.675 GPa, respectively. For maximum stress, neat epoxy showed the best result compared to both nanocomposite due to the changes of material properties when adding the filler into the matrix. Therefore, both nanocomposite increase the mechanical properties of the epoxy, however modification surface of graphene gives better improvement.

  14. Mechanical Properties and Acoustic Emission Properties of Rocks with Different Transverse Scales

    Directory of Open Access Journals (Sweden)

    Xi Yan

    2017-01-01

    Full Text Available Since the stability of engineering rock masses has important practical significance to projects like mining, tunneling, and petroleum engineering, it is necessary to study mechanical properties and stability prediction methods for rocks, cementing materials that are composed of minerals in all shapes and sizes. Rocks will generate acoustic emission during damage failure processes, which is deemed as an effective means of monitoring the stability of coal rocks. In the meantime, actual mining and roadway surrounding rocks tend to have transverse effects; namely, the transverse scale is larger than the length scale. Therefore, it is important to explore mechanical properties and acoustic emission properties of rocks under transverse size effects. Considering the transverse scale effects of rocks, this paper employs the microparticle flow software PFC2D to explore the influence of different aspect ratios on damage mechanics and acoustic emission properties of rocks. The results show that (1 the transverse scale affects uniaxial compression strength of rocks. As the aspect ratio increases, uniaxial compression strength of rocks decreases initially and later increases, showing a V-shape structure and (2 although it affects the maximum hit rate and the strain range of acoustic emission, it has little influence on the period of occurrence. As the transverse scale increases, both damage degree and damage rate of rocks decrease initially and later increase.

  15. Investigation of uranium (VI) extraction mechanisms from phosphoric and sulfuric media by {sup 31}P-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Fries, B.; Marie, C.; Pacary, V.; Berthon, C.; Miguirditchian, M.; Charbonnel, M.C. [CEA, Centre de Marcoule, Nuclear Energy Divison, RadioChemistry and Processes Department - DRCP, F-30207 Bagnols-sur-Ceze (France); Mokhtari, H. [AREVA Mines, Process and Analysis Department - SEPA, F-87250 Bessines-sur-Gartempe (France)

    2016-07-01

    Phosphate rocks contain uranium (∼1000 ppm on average) and are considered as a secondary source for uranium production. Uranium extraction using DEHCNPB (butyl-1-[N,N-bis(2-ethylhexyl)carbamoyl]nonyl phosphonic acid, a bifunctional cationic extractant) has been studied to better understand mechanism differences depending on the original acidic solution (phosphoric or sulfuric). Solvent extraction batch experiments were carried out and the organic phases were probed using {sup 31}P-NMR. This technique enabled to demonstrate that phosphoric acid is poorly extracted by DEHCNPB ([H{sub 3}PO{sub 4}]{sub org} < 2 mM), using direct quantification in the organic phase by {sup 31}P-NMR spectra integration. Moreover, in the presence of uranium in the initial phosphoric acid solution, uranyl extraction by DEHCNPB competes with H{sub 3}PO{sub 4} extraction. Average stoichiometries of U(VI)-DEHCNPB complexes in organic phases were also determined using slope analysis on uranium distribution data. Uranium seems to be extracted from a phosphoric medium by two extractant molecules, whereas more than three DEHCNPB on average would be necessary to extract uranium from a sulfuric medium. Thus, uranium is extracted according to different mechanisms depending on the nature of the initial solution. (authors)

  16. Biomaterials Based on Electrospun Chitosan. Relation between Processing Conditions and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Christian Enrique Garcia Garcia

    2018-03-01

    Full Text Available In this paper, it is shown that pure chitosan nanofibers and films were prepared with success in 0.5 M acetic acid as solvent using poly (ethylene oxide (PEO at different yields, allowing electrospinning of the blends. After processing, a neutralization step of chitosan followed by water washing is performed, preserving the initial morphology of chitosan materials. The influence of the yield in PEO in the blend on the degree of swelling and hydrophilicity of films and nanofibers is demonstrated. Then, the mechanical behavior of blended nanofibers and films used as reference are determined for small stress applied in the linear domain by DMA and by uniaxial traction up to rupture. The dried and wet states are covered for the first time. It is shown that the mechanical properties are increased when electrospinning is performed in the presence of PEO up to a 70/30 chitosan/PEO weight ratio even after PEO extraction. This result can be explained by a better dispersion of the chitosan in the presence of PEO.

  17. Differences in the Phenolic Composition and Antioxidant Properties between Vitis coignetiae and Vitis vinifera Seeds Extracts

    Directory of Open Access Journals (Sweden)

    Ryszard Amarowicz

    2013-03-01

    Full Text Available Phenolic compounds were extracted from European and Japanese grapevine species (Vitis vinifera and V. coignetiae seeds using 80% methanol or 80% acetone. The total content of phenolic compounds was determined utilizing Folin-Ciocalteu’s phenol reagent, while the content of tannins was assayed by the vanillin and BSA precipitation methods. Additionally, the DPPH free radical and ABTS cation radical scavenging activities and the reduction power of the extracts were measured. The HPLC method was applied to determine the phenolic compounds, such as phenolic acids and catechins. The seeds contained large amounts of tannins and gallic acid and observable quantities of catechins, p-coumaric, ferulic and caffeic acids. The dominant form of phenolic acids in the extracts was the ester-bound form. The content of total phenolics was higher in the European grape V. vinifera seeds, which also contained more tannins, catechins and phenolic acids, except for caffeic acid. Extracts from V. vinifera seeds showed better radical scavenger properties and stronger reducing power. The total contents of phenolic compounds and tannins in acetone extracts were higher than in methanolic extracts. Acetone extracts also exhibited stronger antiradical properties as well as stronger reducing power.

  18. Respiratory system dynamical mechanical properties: modeling in time and frequency domain.

    Science.gov (United States)

    Carvalho, Alysson Roncally; Zin, Walter Araujo

    2011-06-01

    The mechanical properties of the respiratory system are important determinants of its function and can be severely compromised in disease. The assessment of respiratory system mechanical properties is thus essential in the management of some disorders as well as in the evaluation of respiratory system adaptations in response to an acute or chronic process. Most often, lungs and chest wall are treated as a linear dynamic system that can be expressed with differential equations, allowing determination of the system's parameters, which will reflect the mechanical properties. However, different models that encompass nonlinear characteristics and also multicompartments have been used in several approaches and most specifically in mechanically ventilated patients with acute lung injury. Additionally, the input impedance over a range of frequencies can be assessed with a convenient excitation method allowing the identification of the mechanical characteristics of the central and peripheral airways as well as lung periphery impedance. With the evolution of computational power, the airway pressure and flow can be recorded and stored for hours, and hence continuous monitoring of the respiratory system mechanical properties is already available in some mechanical ventilators. This review aims to describe some of the most frequently used models for the assessment of the respiratory system mechanical properties in both time and frequency domain.

  19. The influences of N-acetyl cysteine (NAC) on the cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA)-based dental resin.

    Science.gov (United States)

    Jiao, Yang; Ma, Sai; Li, Jing; Shan, Lequn; Yang, Yanwei; Li, Meng; Chen, Jihua

    2015-01-01

    Objectives. This study aimed to investigate the influences of N-acetyl cysteine (NAC) on cytotoxicity and mechanical properties of Poly-methylmethacrylate (PMMA) dental resins. Methods. Experimental PMMA resin was prepared by incorporating various concentrations of NAC (0, 0.15, 0.3, 0.6 and 0.9 wt.%). MTT assay was performed to investigate viability of human dental pulp cells after exposure to extract of PMMA resin with or without NAC. Cell adhesion on resin specimens was examined with scanning electron microscopy. Degree of conversion was studied with Fourier Transform Infrared Spectroscopy (FTIR). Flexural strength, microhardness and surface roughness was evaluated using a universal testing machine, microhardness tester and optical profilometer, respectively. Results. Incorporation of NAC into PMMA resin significantly reduced its cytotoxicity and enhanced cell adhesion on its surface. NAC induced negative influences on the mechanical and physical properties of PMMA resin in a dose-dependent manner. The degree of conversion for all experimental PMMA resins reached as high as 72% after 24 h of polymerization. All the tested properties were maintained when the concentration of incorporated NAC was 0.15 wt.%. Conclusion. The addition of 0.15 wt.% NAC remarkably improved biocompatibility of PMMA resin without exerting significant negative influence on its mechanical and physical properties.

  20. Tissue-Level Mechanical Properties of Bone Contributing to Fracture Risk.

    Science.gov (United States)

    Nyman, Jeffry S; Granke, Mathilde; Singleton, Robert C; Pharr, George M

    2016-08-01

    Tissue-level mechanical properties characterize mechanical behavior independently of microscopic porosity. Specifically, quasi-static nanoindentation provides measurements of modulus (stiffness) and hardness (resistance to yielding) of tissue at the length scale of the lamella, while dynamic nanoindentation assesses time-dependent behavior in the form of storage modulus (stiffness), loss modulus (dampening), and loss factor (ratio of the two). While these properties are useful in establishing how a gene, signaling pathway, or disease of interest affects bone tissue, they generally do not vary with aging after skeletal maturation or with osteoporosis. Heterogeneity in tissue-level mechanical properties or in compositional properties may contribute to fracture risk, but a consensus on whether the contribution is negative or positive has not emerged. In vivo indentation of bone tissue is now possible, and the mechanical resistance to microindentation has the potential for improving fracture risk assessment, though determinants are currently unknown.

  1. Mechanical Behavior Optimization of Chitosan Extracted from Shrimp Shells as a Sustainable Material for Shopping Bags.

    Science.gov (United States)

    D'Angelo, Giacomo; Elhussieny, Amal; Faisal, Marwa; Fahim, I S; Everitt, Nicola M

    2018-05-22

    The use of biodegradable materials for shopping bag production, and other products made from plastics, has recently been an object of intense research-with the aim of reducing the environmental burdens given by conventional materials. Chitosan is a potential material because of its biocompatibility, degradability, and non-toxicity. It is a semi-natural biopolymeric material produced by the deacetylation of chitin, which is the second most abundant natural biopolymer (after cellulose). Chitin is found in the exoskeleton of insects, marine crustaceans, and the cell walls of certain fungi and algae. The raw materials most abundantly available are the shells of crab, shrimp, and prawn. Hence, in this study chitosan was selected as one of the main components of biodegradable materials used for shopping bag production. Firstly, chitin was extracted from shrimp shell waste and then converted to chitosan. The chitosan was next ground to a powder. Although, currently, polyethylene bags are prepared by blown extrusion, in this preliminary research the chitosan powder was dissolved in a solvent and the films were cast. Composite films with several fillers were used as a reinforcement at different dosages to optimize mechanical properties, which have been assessed using tensile tests. These results were compared with those of conventional polyethylene bags used in Egypt. Overall, the chitosan films were found to have a lower ductility but appeared to be strong enough to fulfill shopping bag functions. The addition of fillers, such as chitin whiskers and rice straw, enhanced the mechanical properties of chitosan films, while the addition of chitin worsened overall mechanical behavior.

  2. Mechanical Behavior Optimization of Chitosan Extracted from Shrimp Shells as a Sustainable Material for Shopping Bags

    Directory of Open Access Journals (Sweden)

    Giacomo D’Angelo

    2018-05-01

    Full Text Available The use of biodegradable materials for shopping bag production, and other products made from plastics, has recently been an object of intense research—with the aim of reducing the environmental burdens given by conventional materials. Chitosan is a potential material because of its biocompatibility, degradability, and non-toxicity. It is a semi-natural biopolymeric material produced by the deacetylation of chitin, which is the second most abundant natural biopolymer (after cellulose. Chitin is found in the exoskeleton of insects, marine crustaceans, and the cell walls of certain fungi and algae. The raw materials most abundantly available are the shells of crab, shrimp, and prawn. Hence, in this study chitosan was selected as one of the main components of biodegradable materials used for shopping bag production. Firstly, chitin was extracted from shrimp shell waste and then converted to chitosan. The chitosan was next ground to a powder. Although, currently, polyethylene bags are prepared by blown extrusion, in this preliminary research the chitosan powder was dissolved in a solvent and the films were cast. Composite films with several fillers were used as a reinforcement at different dosages to optimize mechanical properties, which have been assessed using tensile tests. These results were compared with those of conventional polyethylene bags used in Egypt. Overall, the chitosan films were found to have a lower ductility but appeared to be strong enough to fulfill shopping bag functions. The addition of fillers, such as chitin whiskers and rice straw, enhanced the mechanical properties of chitosan films, while the addition of chitin worsened overall mechanical behavior.

  3. Evaluation of antioxidative properties of Geranium macrorrhizum and Potentilla fructiosa extracts in Dutch style fermented sausages

    NARCIS (Netherlands)

    Miliauskas, G.; Mulder, E.; Linssen, J.P.H.; Houben, J.H.; Beek, van T.A.; Venskutonis, P.R.

    2007-01-01

    Antioxidative properties of Geranium macrorrhizum, Potentilla fruticosa and Rosmarinus officinalis (as a reference) extracts were evaluated in Dutch style fermented sausages. Extracts were incorporated into sausages during preparation. The sausages were subsequently fermented, tested and compared to

  4. Inhibition of melanogenesis and antioxidant properties of Magnolia grandiflora L. flower extract

    Directory of Open Access Journals (Sweden)

    Huang Huey-Chun

    2012-06-01

    Full Text Available Abstract Background Magnolia grandiflora L. flower is wildly used in Asian as a traditional herbal medication. The purpose of the study was to investigate the antimelanogenic and antioxidant properties of Magnolia grandiflora L. flower extract. In the study, the inhibitory effects of M. grandiflora L. flower extract on mushroom tyrosinase, B16F10 intracellular tyrosinase activity and melanin content were determined spectrophotometrically. Meanwhile, the antioxidative capacity of the flower extract was also investigated. Results Our results revealed that M. grandiflora L. flower extract inhibit mushroom tyrosinase activity (IC50 =11.1%; v/v, the flower extract also effectively suppressed intracellular tyrosinase activity (IC50 = 13.6%; v/v and decreased the amount of melanin (IC50 = 25.6%; v/v in a dose-dependent manner in B16F10 cells. Protein expression level of tyrosinase and tyrosinase-related protein 1 (TRP-1 were also decreased by the flower extract. Additionally, antioxidant capacities such as ABTS+ free radical scavenging activity, reducing capacity and total phenolic content of the flower extract were increased in a dose-dependent pattern. Conclusions Our results concluded that M. grandiflora L. flower extract decreased the expression of tyrosinase and TRP-1, and then inhibited melanogenesis in B16F10 cells. The flower extract also show antioxidant capacities and depleted cellular reactive oxygen species (ROS. Hence, M. grandiflora L. flower extract could be applied as a type of dermatological whitening agent in skin care products.

  5. Montmorillonite polyaniline nanocomposites: Preparation, characterization and investigation of mechanical properties

    International Nuclear Information System (INIS)

    Soundararajah, Q.Y.; Karunaratne, B.S.B.; Rajapakse, R.M.G.

    2009-01-01

    The interest in clay polymer nanocomposites (CPN) materials, initially developed by researchers at Toyota, has grown dramatically over the last decade. They have attracted great interest, both in industry and in academia, because they often exhibit remarkable improvement in materials' properties when compared with virgin polymer or conventional micro- and macro-composites. These improvements can include high moduli, increased strength and heat resistance, decreased gas permeability and flammability, optical transparency and increased biodegradability of biodegradable polymers. Such enhancement in the properties of nanocomposites occurs mostly due to their unique phase morphology and improved interfacial properties. Because of these enhanced properties they find applications in the fields of electronics, automobile industry, packaging, and construction. This study aims at investigating the mechanical property enhancement of polyaniline (PANI) intercalated with montmorillonite (MMT) clay. The MMT-PANI nanocomposites displayed improved mechanical properties compared to the neat polymer or clay. The enhancement was achieved at low clay content probably due to its exfoliated structure. The increased interfacial areas and improved bond characteristics may attribute to the mechanical property enhancement

  6. Modification of mechanical properties of Si crystal irradiated by Kr-beam

    International Nuclear Information System (INIS)

    Guo, Xiaowei; Momota, Sadao; Nitta, Noriko; Yamaguchi, Takaharu; Sato, Noriyuki; Tokaji, Hideto

    2015-01-01

    Graphical abstract: - Highlights: • Modification of mechanical properties of silicon crystal irradiated by Kr-beam was observed by means of continuous measurements of nano-indentation technique. • Modified mechanical properties show fluence-dependence. • Young's modulus is more sensitive to crystal to amorphous phase transition while hardness is more sensitive to damage induced by ion beam irradiation. • The depth profile of modified mechanical properties have a potential application of determining the longitudinal size of phase transition region induced by nanoindentation. - Abstract: The application of ion-beam irradiation in fabrication of structures with micro-/nanometer scale has achieved striking improvement. However, an inevitable damage results in the change of mechanical properties in irradiated materials. To investigate the relation between mechanical properties and ion-irradiation damages, nanoindentation was performed on crystalline silicon irradiated by Kr-beam with an energy of 240 keV. Modified Young's modulus and nanohardness, provided from the indentation, indicated fluence dependence. Stopping and range of ions in matter (SRIM) calculation, transmission electron microscopy (TEM) observation, and Rutherford backscattering-channeling (RBS-C) measurement were utilized to understand the irradiation effect on mechanical properties. In addition, the longitudinal size of the phase transition region induced by indentation was firstly evaluated based on the depth profile of modified nanohardness

  7. Dependence of Glass Mechanical Properties on Thermal and Pressure History

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Bauchy, Mathieu

    Predicting the properties of new glasses prior to manufacturing is a topic attracting great industrial and scientific interest. Mechanical properties are currently of particular interest given the increasing demand for stronger, thinner, and more flexible glasses in recent years. However, as a non......-equilibrium material, the structure and properties of glass depend not only on its composition, but also on its thermal and pressure histories. Here we review our recent findings regarding the thermal and pressure history dependence of indentation-derived mechanical properties of oxide glasses....

  8. DNA origami compliant nanostructures with tunable mechanical properties.

    Science.gov (United States)

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2014-01-28

    DNA origami enables fabrication of precise nanostructures by programming the self-assembly of DNA. While this approach has been used to make a variety of complex 2D and 3D objects, the mechanical functionality of these structures is limited due to their rigid nature. We explore the fabrication of deformable, or compliant, objects to establish a framework for mechanically functional nanostructures. This compliant design approach is used in macroscopic engineering to make devices including sensors, actuators, and robots. We build compliant nanostructures by utilizing the entropic elasticity of single-stranded DNA (ssDNA) to locally bend bundles of double-stranded DNA into bent geometries whose curvature and mechanical properties can be tuned by controlling the length of ssDNA strands. We demonstrate an ability to achieve a wide range of geometries by adjusting a few strands in the nanostructure design. We further developed a mechanical model to predict both geometry and mechanical properties of our compliant nanostructures that agrees well with experiments. Our results provide a basis for the design of mechanically functional DNA origami devices and materials.

  9. Lithophysal Rock Mass Mechanical Properties of the Repository Host Horizon

    International Nuclear Information System (INIS)

    D. Rigby

    2004-01-01

    The purpose of this calculation is to develop estimates of key mechanical properties for the lithophysal rock masses of the Topopah Spring Tuff (Tpt) within the repository host horizon, including their uncertainties and spatial variability. The mechanical properties to be characterized include an elastic parameter, Young's modulus, and a strength parameter, uniaxial compressive strength. Since lithophysal porosity is used as a surrogate property to develop the distributions of the mechanical properties, an estimate of the distribution of lithophysal porosity is also developed. The resulting characterizations of rock parameters are important for supporting the subsurface design, developing the preclosure safety analysis, and assessing the postclosure performance of the repository (e.g., drift degradation and modeling of rockfall impacts on engineered barrier system components)

  10. Antioxidant properties of Taraxacum officinale fruit extract are involved in the protective effect against cellular death induced by sodium nitroprusside in brain of rats.

    Science.gov (United States)

    Colle, Dirleise; Arantes, Letícia Priscilla; Rauber, Ricardo; de Mattos, Sérgio Edgar Campos; Rocha, João Batista Teixeira da; Nogueira, Cristina Wayne; Soares, Félix Alexandre Antunes

    2012-07-01

    Taraxacum officinale Weber (Asteraceae), known as dandelion, is used for medicinal purposes due to its choleretic, diuretic, antitumor, antioxidant, antiinflammatory, and hepatoprotective properties. We sought to investigate the protective activity of T. officinale fruit extract against sodium nitroprusside (SNP)-induced decreased cellular viability and increased lipid peroxidation in the cortex, hippocampus, and striatum of rats in vitro. To explain the mechanism of the extract's antioxidant activity, its putative scavenger activities against NO, DPPH·, OH·, and H(2)O(2) were determined. Slices of cortex, hippocampus, and striatum were treated with 50 μM SNP and T. officinale fruit ethanolic extract (1-20 µg/mL) to determine cellular viability by MTT reduction assay. Lipid peroxidation was measure in cortical, hippocampal and striatal slices incubates with SNP (5 µM) and T. officinale fruit extract (1-20 µg/mL). We also determined the scavenger activities of T. officinale fruit extract against NO·, DPPH·, OH·, and H(2)O(2), as well as its iron chelating capacity. The extract (1, 5, 10, and 20 μg/mL) protected against SNP-induced decreases in cellular viability and increases in lipid peroxidation in the cortex, hippocampus, and striatum of rats. The extract had scavenger activity against DPPH· and NO· at low concentrations and was able to protect against H(2)O(2) and Fe(2+)-induced deoxyribose oxidation. T. officinale fruit extract has antioxidant activity and protects brain slices against SNP-induced cellular death. Possible mechanisms of action include its scavenger activities against reactive oxygen species (ROS) and reactive nitrogen species (RNS), which are attributed to the presence of phenolic compounds in the extract.

  11. Bone biopsy needles. Mechanical properties, needle design and specimen quality

    International Nuclear Information System (INIS)

    Keulers, Annika; Penzkofer, T.; Cunha-Cruz, V.C.; Bruners, P.; Helmholtz Inst. fuer biomedizinische Technik, Aachen; Braunschweig, T.; Schmitz-Rode, T.; Mahnken, A.; Helmholtz Inst. fuer biomedizinische Technik, Aachen

    2011-01-01

    To quantitatively analyze differences in mechanical properties, needle design including signs of wear, subjective handling and specimen quality of bone biopsy needles. Materials and Methods: In this study 19 different bone biopsy systems (total 38; 2 /type) were examined. With each biopsy needle five consecutive samples were obtained from vertebral bodies of swine. During puncture a force-torques sensor measured the mechanical properties and subjective handling was assessed. Before and after each biopsy the needles were investigated using a profile projector and signs of wear were recorded. Afterwards, a pathologist semi-quantitatively examined the specimen regarding sample quality. The overall evaluation considered mechanical properties, needle wear, subjective handling and sample quality. Differences were assessed for statistical significance using ANOVA and t-test. Results: Needle diameter (p = 0.003) as well as needle design (p = 0.008) affect the mechanical properties significantly. Franseen design is significantly superior to other needle designs. Besides, length reduction recorded by the profile projector, as a quality criterion showed notable distinctions in between the needle designs. Conclusion: Bone biopsy needles vary significantly in performance. Needle design has an important influence on mechanical properties, handling and specimen quality. Detailed knowledge of those parameters would improve selecting the appropriate bone biopsy needle. (orig.)

  12. Effect of commercial grape extracts on the cheese-making properties of milk.

    Science.gov (United States)

    Felix da Silva, Denise; Matumoto-Pintro, Paula T; Bazinet, Laurent; Couillard, Charles; Britten, Michel

    2015-03-01

    Grape extracts can be added to milk to produce cheese with a high concentration of polyphenols. Four commercial extracts from whole grape, grape seed, and grape skin (2 extracts) were characterized and added to milk at concentrations of 0, 0.1, 0.2, and 0.3% (wt/vol). The effect of grape extracts on the kinetics of milk clotting, milk gel texture, and syneresis were determined, and model cheeses were produced. Whole grape and grape seed extracts contained a similar concentration of polyphenolic compounds and about twice the amount found in grape skin extracts. Radical scavenging activity was directly proportional to the phenolic compounds content. When added to milk, grape extracts increased rennet-induced clotting time and decreased the clotting rate. Although differences were observed between the extracts, the concentration added to milk was the main factor influencing clotting properties. With increasing concentrations of grape extracts, milk gels showed increased brittleness and reduced firmness. In addition, syneresis of milk gels decreased with increasing concentrations of grape extracts, which resulted in cheeses with a higher moisture content. The presence of grape extracts in milk slightly increased protein recovery in cheese but had no effect on fat recovery. With whole grape or grape seed extracts added to milk at 0.1% (wt/vol), the recovery coefficient for polyphenols was about 0.63, and decreased with increasing extract concentration in milk. Better polyphenol recovery was observed for grape seed extracts (0.87), with no concentration effect. Commercial extracts from whole grape, grape seed, or grape skin can be added to milk in the 0.1 to 0.3% (wt/vol) concentration range to produce cheese with potential health benefits, without a negative effect on cheese yield. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Green tea extract impairs meat emulsion properties by disturbing protein disulfide cross-linking.

    Science.gov (United States)

    Jongberg, Sisse; Terkelsen, Linda de S; Miklos, Rikke; Lund, Marianne N

    2015-02-01

    The dose-dependent effects of green tea extract (100, 500, or 1500ppm) on the textural and oxidative stability of meat emulsions were investigated, and compared to a control meat emulsion without extract. All levels of green tea extract inhibited formation of TBARS as a measure for lipid oxidation. Overall protein thiol oxidation and myosin heavy chain (MHC) cross-linking were inhibited by 100ppm green tea extract without jeopardizing the textural stability, while increasing concentrations of extract resulted in reduced thiol concentration and elevated levels of non-reducible protein modifications. Addition of 1500ppm green tea extract was found to modify MHC as evaluated by SDS-PAGE combining both protein staining and specific thiol staining, indicating that protein modifications generated through reactions of green tea phenolic compounds with protein thiols, disrupted the meat emulsion properties leading to reduced water holding capacity and textural stability. Hence, a low dose of green tea extract preserves both the textural and the oxidative stability of the meat proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Characterizing the macro and micro mechanical properties of scaffolds for rotator cuff repair.

    Science.gov (United States)

    Smith, Richard D J; Zargar, Nasim; Brown, Cameron P; Nagra, Navraj S; Dakin, Stephanie G; Snelling, Sarah J B; Hakimi, Osnat; Carr, Andrew

    2017-11-01

    Retearing after rotator cuff surgery is a major clinical problem. Numerous scaffolds are being used to try to reduce retear rates. However, few have demonstrated clinical efficacy. We hypothesize that this lack of efficacy is due to insufficient mechanical properties. Therefore, we compared the macro and nano/micro mechanical properties of 7 commercially available scaffolds to those of the human supraspinatus tendons, whose function they seek to restore. The clinically approved scaffolds tested were X-Repair, LARS ligament, Poly-Tape, BioFiber, GraftJacket, Permacol, and Conexa. Fresh frozen cadaveric human supraspinatus tendon samples were used. Macro mechanical properties were determined through tensile testing and rheometry. Scanning probe microscopy and scanning electron microscopy were performed to assess properties of materials at the nano/microscale (morphology, Young modulus, loss tangent). None of the scaffolds tested adequately approximated both the macro and micro mechanical properties of human supraspinatus tendon. Macroscale mechanical properties were insufficient to restore load-bearing function. The best-performing scaffolds on the macroscale (X-Repair, LARS ligament) had poor nano/microscale properties. Scaffolds approximating tendon properties on the nano/microscale (BioFiber, biologic scaffolds) had poor macroscale properties. Existing scaffolds failed to adequately approximate the mechanical properties of human supraspinatus tendons. Combining the macroscopic mechanical properties of a synthetic scaffold with the micro mechanical properties of biologic scaffold could better achieve this goal. Future work should focus on advancing techniques to create new scaffolds with more desirable mechanical properties. This may help improve outcomes for rotator cuff surgery patients. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  15. Electro-optical and physic-mechanical properties of colored alicyclic polyimide

    Science.gov (United States)

    Kravtsova, V.; Umerzakova, M.; Korobova, N.; Timoshenkov, S.; Timoshenkov, V.; Orlov, S.; Iskakov, R.; Prikhodko, O.

    2016-09-01

    Main optical, thermal and mechanical properties of new compositions based on alicyclic polyimide and active bright red 6C synthetic dye have been studied. It was shown that the transmission ratio of the new material in the region of 400-900 nm and 2.0 wt.% dye concentration was around 60-70%. Thermal, mechanical and electrical properties of new colored compositions were comparable with the properties of original polyimide.

  16. Physicochemical Properties of Gelatin Extracted from Buffalo Hide Pretreated with Different Acids.

    Science.gov (United States)

    Mulyani, Sri; Setyabudi, Francis M C Sigit; Pranoto, Yudi; Santoso, Umar

    2017-01-01

    The acid pretreatment of collagen molecules disrupts their crosslinks and assists in the release of acid-soluble proteins, fats, and other components. Generally, to achieve optimum extraction efficiency, strong acids may be used at a lower acid concentration compared to weak acids. This study aimed to determine the yield and physicochemical properties of gelatins extracted from buffalo hides pretreated with different acids. Hides were extracted with hydrochloric, citric, and acetic acids at concentrations of 0.3, 0.6, 0.9, 1.2, and 1.5 M. A completely randomized design and the least significant difference test were used in the experimental design, and all measurements were performed in triplicate. The highest yield (29.17%) was obtained from pretreatment with 0.9 M HCl. The gel strength did not differ significantly ( p >0.05) according to acid type (280.26-259.62 g Bloom), and the highest viscosity was obtained from the 0.6 M citric acid pretreatment. All the gelatins contained α- and β-chain components and several degraded peptides (24-66 kDa). The color and Fourier-transform infrared spectrum of the gelatin extracted using 0.9 M HCl were similar to those of commercial bovine skin gelatin. In general, the physicochemical properties of the gelatin complied with the industry standard set by the Gelatin Manufacturers Institute of America, revealing that buffalo hide could serve as a potential alternative source of gelatin.

  17. Mechanical properties of soldered joints of niobium base alloys

    International Nuclear Information System (INIS)

    Grishin, V.L.

    1980-01-01

    Mechanical properties of soldered joints of niobium alloys widely distributed in industry: VN3, VN4, VN5A, VN5AE, VN5AEP etc., 0.6-1.2 mm thick are investigated. It is found out that the usage of zirconium-vanadium, titanium-tantalum solders for welding niobium base alloys permits to obtain soldered joints with satisfactory mechanical properties at elevated temperatures

  18. Fuel cladding mechanical properties for transient analysis

    International Nuclear Information System (INIS)

    Johnson, G.D.; Hunter, C.W.; Hanson, J.E.

    1976-01-01

    Out-of-pile simulated transient tests have been conducted on irradiated fast-reactor fuel pin cladding specimens at heating rates of 10 0 F/s (5.6 0 K/s) and 200 0 F/s (111 0 K/s) to generate mechanical property information for use in describing cladding behavior during off-normal events. Mechanical property data were then analyzed, applying the Larson-Miller Parameter to the effects of heating rate and neutron fluence. Data from simulated transient tests on TREAT-tested fuel pins demonstrate that Plant Protective System termination of 3$/s transients prevents significant damage to cladding. The breach opening produced during simulated transient testing is shown to decrease in size with increasing neutron fluence

  19. Characterization of porosity in support of mechanical property analysis

    International Nuclear Information System (INIS)

    Price, R.H.; Martin, R.J. III; Boyd, P.J.

    1993-01-01

    The general applicability of laboratory data for engineering purposes is a prime concern for the design and licensing of a potential repository of high level nuclear waste at Yucca Mountain. In order for the results of experiments to be applicable to the repository scale, the data must be scaled to in situ size and conditions. Previous laboratory investigations of tuff have shown that porosity has a dominant, general effect on mechanical properties. As a result, it is very important for the interpretation of mechanical property data that porosity is measured on each sampled test. Porosity alone, however, does not address all of the issues important to mechanical behavior. Variability in size and distribution of pore space produces significantly different mechanical properties. A nondestructive technique for characterizing the internal structure of the sample prior to testing is being developed and the results are being analyzed. The information obtained from this technique can help in both qualitative and quantitative interpretation of test results

  20. Simple display system of mechanical properties of cells and their dispersion.

    Directory of Open Access Journals (Sweden)

    Yuji Shimizu

    Full Text Available The mechanical properties of cells are unique indicators of their states and functions. Though, it is difficult to recognize the degrees of mechanical properties, due to small size of the cell and broad distribution of the mechanical properties. Here, we developed a simple virtual reality system for presenting the mechanical properties of cells and their dispersion using a haptic device and a PC. This system simulates atomic force microscopy (AFM nanoindentation experiments for floating cells in virtual environments. An operator can virtually position the AFM spherical probe over a round cell with the haptic handle on the PC monitor and feel the force interaction. The Young's modulus of mesenchymal stem cells and HEK293 cells in the floating state was measured by AFM. The distribution of the Young's modulus of these cells was broad, and the distribution complied with a log-normal pattern. To represent the mechanical properties together with the cell variance, we used log-normal distribution-dependent random number determined by the mode and variance values of the Young's modulus of these cells. The represented Young's modulus was determined for each touching event of the probe surface and the cell object, and the haptic device-generating force was calculated using a Hertz model corresponding to the indentation depth and the fixed Young's modulus value. Using this system, we can feel the mechanical properties and their dispersion in each cell type in real time. This system will help us not only recognize the degrees of mechanical properties of diverse cells but also share them with others.

  1. Rhenium Mechanical Properties and Joining Technology

    Science.gov (United States)

    Reed, Brian D.; Biaglow, James A.

    1996-01-01

    Iridium-coated rhenium (Ir/Re) provides thermal margin for high performance and long life radiation cooled rockets. Two issues that have arisen in the development of flight Ir/Re engines are the sparsity of rhenium (Re) mechanical property data (particularly at high temperatures) required for engineering design, and the inability to directly electron beam weld Re chambers to C103 nozzle skirts. To address these issues, a Re mechanical property database is being established and techniques for creating Re/C103 transition joints are being investigated. This paper discusses the tensile testing results of powder metallurgy Re samples at temperatures from 1370 to 2090 C. Also discussed is the evaluation of Re/C103 transition pieces joined by both, explosive and diffusion bonding. Finally, the evaluation of full size Re transition pieces, joined by inertia welding, as well as explosive and diffusion bonding, is detailed.

  2. Effect of Gleditsia sinensis Lam. Extract on Physico-Chemical Properties of Emulsion-Type Pork Sausages.

    Science.gov (United States)

    Jin, Sang-Keun; Yang, Han-Sul; Choi, Jung-Seok

    2017-01-01

    This study was performed to investigate the effect of Gleditsia sinensis Lam. extract on the physicochemical properties of emulsion-type pork sausages during storage at 10°C for 4 wk. Treatments were as follows: (C, control; T1, sodium ascorbate 0.05%; T2, Gleditsia sinensis Lam. 0.05%; T3, Gleditsia sinensis Lam. 0.1%; T4, Gleditsia sinensis Lam. 0.2%; T5, Gleditsia sinensis Lam. 0.1% + sodium ascorbate 0.05%). The values of pH, moisture content, lightness, redness, and sensory attributes were all significantly decreased, while the yellowness, chroma, hue angle, and texture properties were increased during storage with increase of the Gleditsia sinensis Lam. extract added. In addition, the antioxidant activity and antimicrobial activity in the sausages displayed significant increases ( p <0.05). Therefore, although it was concluded that the addition of Gleditsia sinensis Lam. extract is not effective for improvement of the physical properties compared to chemical additives in sausages, it could be applied to meat products as a natural preservatives.

  3. Mechanical properties of different types of space maintainers

    Science.gov (United States)

    Beldiman, M.-A.; Mârţu, I.; Leiţoiu, B.; Luchian, I.; Lupescu, O.; Bârcă, E. S.

    2015-11-01

    Currently, inside the oral cavity, the dental space maintainers are subjected to forces exerted on them when performing various functions; therefore, it is important to know how each of these mechanisms behave and respond to forces that are applied directly to them. The mechanical properties of the materials used in dentistry are defined by a set of characteristics representing the behaviour of their particular working conditions and it is qualitatively expressed by a number of parameters.The study aimed to determine the pressing force that can be taken by four 4 types of space maintainers frequently used in practice - fixed and removable, applied on four samples realized with human teeth extracted for orthodontic purposes. Static tests were carried out on a machine type short WDW-5 EC with a maximum force of 5 kN and a loading speed of 5 mm/min by a special testing machine, with an innovative appliance; data recording was automatically performed, using a computer with a special program that present the specific diagrams. Experimental determinations included the following aspects: to determine the maximum force that can be supported by each sample, and to observe the deformations. The values obtained indicate that the best option in terms of behavior under the conditions specified is the removable appliance, and the less functional version is the fixed space maintainer using brackets. According to tests conducted, the fracture strength was found to be more important for fixed space maintainers (band and loop, for example) so, in practice is using more frequent these types of space maintainers.

  4. Computer simulations of the mechanical properties of metals

    DEFF Research Database (Denmark)

    Schiøtz, Jakob; Vegge, Tejs

    1999-01-01

    Atomic-scale computer simulations can be used to gain a better understanding of the mechanical properties of materials. In this paper we demonstrate how this can be done in the case of nanocrystalline copper, and give a brief overview of how simulations may be extended to larger length scales....... Nanocrystline metals are metals with grain sizes in the nanometre range, they have a number of technologically interesting properties such as much increased hardness and yield strength. Our simulations show that the deformation mechanisms are different in these materials than in coarse-grained materials...

  5. Mechanical Properties and Durability of CNT Cement Composites

    Directory of Open Access Journals (Sweden)

    María del Carmen Camacho

    2014-02-01

    Full Text Available In the present paper, changes in mechanical properties of Portland cement-based mortars due to the addition of carbon nanotubes (CNT and corrosion of embedded steel rebars in CNT cement pastes are reported. Bending strength, compression strength, porosity and density of mortars were determined and related to the CNT dosages. CNT cement paste specimens were exposed to carbonation and chloride attacks, and results on steel corrosion rate tests were related to CNT dosages. The increase in CNT content implies no significant variations of mechanical properties but higher steel corrosion intensities were observed.

  6. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

    OpenAIRE

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability ...

  7. Preparation and Mechanical Properties of Aligned Discontinuous Carbon Fiber Composites

    OpenAIRE

    DENG Hua; GAO Junpeng; BAO Jianwen

    2018-01-01

    Aligned discontinuous carbon fiber composites were fabricated from aligned discontinuous carbon fiber prepreg, which was prepared from continuous carbon fiber prepreg via mechanical high-frequency cutting. The internal quality and mechanical properties were characterized and compared with continuous carbon fiber composites. The results show that the internal quality of the aligned discontinuous carbon fiber composites is fine and the mechanical properties have high retention rate after the fi...

  8. Swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) hydrogels.

    Science.gov (United States)

    Suzuki, Atsushi; Sasaki, Saori

    2015-12-01

    Physically crosslinked poly(vinyl alcohol) gels are versatile biomaterials due to their excellent biocompatibility. In the past decades, physically crosslinked poly(vinyl alcohol) and poly(vinyl alcohol)-based hydrogels have been extensively studied for biomedical applications. However, these materials have not yet been implemented due to their mechanical strength. Physically crosslinked poly(vinyl alcohol) gels consist of a swollen amorphous network of poly(vinyl alcohol) physically crosslinked by microcrystallites. Although the mechanical properties can be improved to some extent by controlling the distribution of microcrystallites on the nano- and micro-scales, enhancing the mechanical properties while maintaining high water content remains very difficult. It may be technologically impossible to significantly improve the mechanical properties while keeping the gel's high water absorbance ability using conventional fabrication methods. Physical and chemical understandings of the swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) gels are considered here; some promising strategies for their practical applications are presented. This review focuses more on the recent studies on swelling and mechanical properties of poly(vinyl alcohol) hydrogels, prepared using only poly(vinyl alcohol) and pure water with no other chemicals, as potential biomedical materials. © IMechE 2015.

  9. Study of mechanical properties and fracture mechanisms of synthetic fibers nylon-and-polyester type, used in engineering products

    International Nuclear Information System (INIS)

    Cardoso, Sergio Gomes

    2009-01-01

    Fibers are groups formed by molecular-chain-oriented filaments. Fibers play a fundamental role in human being's daily life and they can be found in several forms and geometries, such as filaments, yarns, beams, rope, fabric, composite, coatings, others. They are used in various segments such as civil, mechanical, electrical, electronics, military, naval, nautical, aviation, health, medicine, environment, communications, safety, space, others. Fibers are divided into two distinct classes: natural and chemical ones, which cover synthetic and man-made sub-classes. They can be produced from several materials, such as wool, cotton, rayon, flax, silk, rock, nylon, polyester, polyethylene, poly-propylene, aramid, glass, carbon, steel, ceramic, others. Globally, the participation of chemical fibers corresponds to approximately 59,9%, and the synthetic fiber polyester, the most used one, represents approximately 63% of the world market. Vital needs have led to the development of multi-function fibers and the focus has changed in the last 10 years with the use of nano technology for environmental responsibility and smart fibers. The study of mechanical properties and fracture mechanisms of fibers is of great relevance for characterization and understanding of causes as consequence of failures. For such reason, it was selected technical fabrics made of high performance synthetic fiber nylon-and-polyester type, used in engineered products such as tires, belts, hoses and pneumatic springs, which have been analyzed in each processing phase. Fiber samples were extracted after each processing phase to be analyzed, by traction destructive tests and scanning electron microscopy. The results of analysis of mechanical properties showed loss of resistance to temperature and multi axial stress during fiber processing phase. Through microscopy tests, it was possible to find contamination, surface stains, plastic deformations, scaling, variations in the fracture faces of the filaments and

  10. Mechanical properties of roll extruded nuclear reactor piping

    International Nuclear Information System (INIS)

    Steichen, J.M.; Knecht, R.L.

    1975-01-01

    The elevated temperature mechanical properties of large diameter (28 inches) seamless pipe produced by roll extrusion for use as primary piping for sodium coolant in the Fast Flux Test Facility (FFTF) have been characterized. The three heats of Type 316H stainless steel piping material used exhibited consistent mechanical properties and chemical compositions. Tensile and creep-rupture properties exceeded values on which the allowable stresses for ASME Code Case 1592 on Nuclear Components in Elevated Temperature Service were based. Tensile strength and ductility were essentially unchanged by aging in static sodium at 1050 0 F for times to 10,000 hours. High strain rate tensile tests showed that tensile properties were insensitive to strain rate at temperatures to 900 0 F and that for temperatures of 1050 0 F and above both strength and ductility significantly increased with increasing strain rate. Fatigue-crack propagation properties were comparable to results obtained on plate material and no differences in crack propagation were found between axial and circumferential orientations. (U.S.)

  11. Mechanical properties of canine osteosarcoma-affected antebrachia.

    Science.gov (United States)

    Steffey, Michele A; Garcia, Tanya C; Daniel, Leticia; Zwingenberger, Allison L; Stover, Susan M

    2017-05-01

    To determine the influence of neoplasia on the biomechanical properties of canine antebrachia. Ex vivo biomechanical study. Osteosarcoma (OSA)-affected canine antebrachia (n = 12) and unaffected canine antebrachia (n = 9). Antebrachia were compressed in axial loading until failure. A load-deformation curve was used to acquire the structural mechanical properties of neoplastic and unaffected specimens. Structural properties and properties normalized by body weight (BW) and radius length were compared using analysis of variance (ANOVA). Modes of failure were compared descriptively. Neoplastic antebrachia fractured at, or adjacent to, the OSA in the distal radial diaphysis. Unaffected antebrachia failed via mid-diaphyseal radial fractures with a transverse cranial component and an oblique caudal component. Structural mechanical properties were more variable in neoplastic antebrachia than unaffected antebrachia, which was partially attributable to differences in bone geometry related to dog size. When normalized by dog BW and radial length, strength, stiffness, and energy to yield and failure, were lower in neoplastic antebrachia than in unaffected antebrachia. OSA of the distal radial metaphysis in dogs presented for limb amputation markedly compromises the structural integrity of affected antebrachia. However, biomechanical properties of affected bones was sufficient for weight-bearing, as none of the neoplastic antebrachia fractured before amputation. The behavior of tumor invaded bone under cyclic loading warrants further investigations to evaluate the viability of in situ therapies for bone tumors in dogs. © 2017 The American College of Veterinary Surgeons.

  12. The mechanism for degrading Orange II based on adsorption and reduction by ion-based nanoparticles synthesized by grape leaf extract

    International Nuclear Information System (INIS)

    Luo, Fang; Yang, Die; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

    2015-01-01

    Biomolecules taken from plant extracts have often been used in the single-step synthesis of iron-based nanoparticles (Fe NPs) due to their low cost, environmental safety and sustainable properties. However, the composition of Fe NPs and the degradation mechanism of organic contaminants by them are limited because these are linked to the reactivity of Fe NPs. In this study, Fe NPs synthesized by grape leaf extract served to remove Orange II. Batch experiments showed that more than 92% of Orange II was removed by Fe NPs at high temperature based on adsorption and reduction and confirmed by kinetic studies. To understand the role of Fe NPs in the removal process of azo dye, surface analysis via X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed, showing that the Fe NPs were composed of biomolecules, hydrous iron oxides and Fe 0 , thus providing evidence for the adsorption of Orange II onto hydrous iron oxides and its reduction by Fe 0 . Degraded products such as 2-naphthol were identified using LC–MS analysis. A degradation mechanism based on asymmetrical azo bond cleavage for the removal of Orange II was proposed

  13. The mechanism for degrading Orange II based on adsorption and reduction by ion-based nanoparticles synthesized by grape leaf extract

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Fang; Yang, Die [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, University of South Australia, Mawson Lakes, SA 5095 (Australia); Chen, Zuliang, E-mail: zuliang.chen@unisa.edu.au [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, University of South Australia, Mawson Lakes, SA 5095 (Australia); Megharaj, Mallavarapu; Naidu, Ravendra [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of Environments, University of South Australia, Mawson Lakes, SA 5095 (Australia)

    2015-10-15

    Biomolecules taken from plant extracts have often been used in the single-step synthesis of iron-based nanoparticles (Fe NPs) due to their low cost, environmental safety and sustainable properties. However, the composition of Fe NPs and the degradation mechanism of organic contaminants by them are limited because these are linked to the reactivity of Fe NPs. In this study, Fe NPs synthesized by grape leaf extract served to remove Orange II. Batch experiments showed that more than 92% of Orange II was removed by Fe NPs at high temperature based on adsorption and reduction and confirmed by kinetic studies. To understand the role of Fe NPs in the removal process of azo dye, surface analysis via X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) were employed, showing that the Fe NPs were composed of biomolecules, hydrous iron oxides and Fe{sup 0}, thus providing evidence for the adsorption of Orange II onto hydrous iron oxides and its reduction by Fe{sup 0}. Degraded products such as 2-naphthol were identified using LC–MS analysis. A degradation mechanism based on asymmetrical azo bond cleavage for the removal of Orange II was proposed.

  14. Correlation between the mechanical and histological properties of liver tissue.

    Science.gov (United States)

    Yarpuzlu, Berkay; Ayyildiz, Mehmet; Tok, Olgu Enis; Aktas, Ranan Gulhan; Basdogan, Cagatay

    2014-01-01

    In order to gain further insight into the mechanisms of tissue damage during the progression of liver diseases as well as the liver preservation for transplantation, an improved understanding of the relation between the mechanical and histological properties of liver is necessary. We suggest that this relation can only be established truly if the changes in the states of those properties are investigated dynamically as a function of post mortem time. In this regard, we first perform mechanical characterization experiments on three bovine livers to investigate the changes in gross mechanical properties (stiffness, viscosity, and fracture toughness) for the preservation periods of 5, 11, 17, 29, 41 and 53h after harvesting. Then, the histological examination is performed on the samples taken from the same livers to investigate the changes in apoptotic cell count, collagen accumulation, sinusoidal dilatation, and glycogen deposition as a function of the same preservation periods. Finally, the correlation between the mechanical and histological properties is investigated via the Spearman's Rank-Order Correlation method. The results of our study show that stiffness, viscosity, and fracture toughness of bovine liver increase as the preservation period is increased. These macroscopic changes are very strongly correlated with the increase in collagen accumulation and decrease in deposited glycogen level at the microscopic level. Also, we observe that the largest changes in mechanical and histological properties occur after the first 11-17h of preservation. © 2013 Elsevier Ltd. All rights reserved.

  15. Mechanical properties of flexible knitted composites

    NARCIS (Netherlands)

    Haan, de J.; Peijs, A.A.J.M.

    1996-01-01

    This study investigates the influence of the matrix material and the degree of prestretch of a knitted fibre structure on the mechanical properties of knitted composites with low fibre volume fractions. By embedding a flexible textile structure in an elastomeric matrix, composite materials are

  16. Modeling mechanical properties of cast aluminum alloy using artificial neural network

    International Nuclear Information System (INIS)

    Jokhio, M.H.; Panhwar, M.I.

    2009-01-01

    Modeling is widely used to investigate the mechanical properties of engineering materials due to increasing demand of low cost and high strength to weight ratio for many engineering applications. The aluminum casting alloys are cost competitive material and possess the desired properties. The mechanical properties largely depend upon composition of alloys and their processing method. Alloy design involves controlling mechanical properties via optimization of the composition and processing parameters. For optimization the possible root is empirical modeling and its more refined version is the analysis of the wide range of data using ANN (Artificial Neural Networks) modeling. The modeling of mechanical properties of the aluminum alloys are the main objective of present work. For this purpose, some data were collected and experimentally prepared using conventional casting method. A MLP (Multilayer Perceptron) network was developed, which is trained by using the error back propagation algorithm. (author)

  17. Examination of the Thermo-mechanical Properties of E-Glass/Carbon Composites

    Directory of Open Access Journals (Sweden)

    Hande Sezgin

    2017-12-01

    Full Text Available Eight-ply E-glass, carbon and E-glass/carbon fabric-reinforced polyester based hybrid composites were manufactured in this study. A vacuum infusion system was used as the production method. Dynamic mechanical analysis, thermogravimetric analysis and differential scanning calorimetry analysis were conducted to examine the thermo-mechanical properties of composite samples. The effect of reinforcement type and different stacking sequences of fabric plies on the thermo-mechanical properties of composite samples were also investigated. Results showed that the type and alignment of reinforcement material has a signifi cant effect on the dynamic mechanical properties of composite samples.

  18. Radiation Improved Mechanical and Thermal Property of PP/HDPE

    International Nuclear Information System (INIS)

    Chaisupaditsin, M.; Thammit, C.; Techakiatkul, C.

    1998-01-01

    The mechanical properties, thermal properties and gel contents of PP-irradiated HDPE blends were studied. HDPE was gamma irradiated in the dose range of 10-30 kGy. The ratios of polymer blends of 30PP:70HDPE was mixed by a twin screw extruder at speed of 50 rpm. Irradiated HDPE with 30 kGy showed the highest gel contents. The blends ratio of 30PP:70HDPE (30 kGy) shows better heat resistance than the blends with non-irradiated HDPE. With increasing the radiation doses, the mechanical properties of the blends were improved

  19. Unique microstructure and excellent mechanical properties of ADI

    Directory of Open Access Journals (Sweden)

    Jincheng Liu

    2006-11-01

    Full Text Available Amongst the cast iron family, ADI has a unique microstructure and an excellent, optimised combination of mechanical properties. The main microstructure of ADI is ausferrite, which is a mixture ofextremely fine acicular ferrite and stable, high carbon austenite. There are two types of austenite in ADI:(1 the coarser and more equiaxed blocks of austenite between non-parallel acicular structures, which exist mainly in the last solidified area, and (2 the thin films of ustenite between the individual ferriteplatelets in the acicular structure. It is this unique microstructure, which gives ADI its excellent static and dynamic properties, and good low temperature impact toughness. The effect of microstructure on the mechanical properties is explained in more detail by examining the microstructure at the atomic scale. Considering the nanometer grain sizes, the unique microstructure, the excellent mechanical properties,good castability, (which enables near net shape components to be produced economically and in large volumes, and the fact that it can be 100% recycled, it is not overemphasized to call ADI a high-tech,nanometer and “green” material. ADI still has the potential to be further improved and its production and the number of applications for ADI will continue to grow, driven by the resultant cost savings over alternative materials.

  20. Antidiarrhoeal property of the hydroethanolic extract of the flowering tops of Anthocephalus cadamba

    Directory of Open Access Journals (Sweden)

    M. Ashraful Alam

    Full Text Available The antidiarrhoeal property of the hydroethanolic extract of the flowering tops of Anthocephalus cadamba was assessed on experimental animals. The dry hydroethanolic extract (250-500 mg/kg body mass, p.o. exhibited a dose-dependent decrease in the total number of faecal droppings in castor oil-induced diarrhoea in mice. The extract also produced a significant (p < 0.01 and dose-dependent reduction in intestinal fluids accumulation and in the gastrointestinal transit from 64.59 % and 71.19% at doses of 250 and 500 mg/kg. The reduction rates were 37.85% and 74.91%, respectively, with the control and standard drug group.

  1. Effects of surface atomistic modification on mechanical properties of gold nanowires

    International Nuclear Information System (INIS)

    Sun, Xiao-Yu; Xu, Yuanjie; Wang, Gang-Feng; Gu, Yuantong; Feng, Xi-Qiao

    2015-01-01

    Highlights: • Molecular dynamics simulations of surface modification effect of Au nanowires. • Surface modification can greatly affect the mechanical properties of nanowires. • Core–shell model is used to elucidate the effect of residual surface stress. - Abstract: Modulation of the physical and mechanical properties of nanowires is a challenging issue for their technological applications. In this paper, we investigate the effects of surface modification on the mechanical properties of gold nanowires by performing molecular dynamics simulations. It is found that by modifying a small density of silver atoms to the surface of a gold nanowire, the residual surface stress state can be altered, rendering a great improvement of its plastic yield strength. This finding is in good agreement with experimental measurements. The underlying physical mechanisms are analyzed by a core–shell nanowire model. The results are helpful for the design and optimization of advanced nanomaterial with superior mechanical properties

  2. Biomechanical and ultrastructural comparison of cryopreservation and a novel cellular extraction of porcine aortic valve leaflets.

    Science.gov (United States)

    Courtman, D W; Pereira, C A; Omar, S; Langdon, S E; Lee, J M; Wilson, G J

    1995-12-01

    Heart valve substitutes of biological origin often fail by degenerative mechanisms. Many authors have hypothesized that mechanical fatigue and structural degradation are instrumental to in vivo failure. Since the properties of the structural matrix at implantation may predetermine failure, we have examined the ultrastructure, fracture, mechanics, and uniaxial high-strain-rate viscoelastic properties of: (1) fresh, (2) cryopreserved, and (3) cellular extracted porcine aortic valve leaflets. The cellular extraction process is being developed in order to reduce immunological attack and calcification. Cryopreservation causes cellular disruption and necrotic changes throughout the tissue, whereas extraction removes all cells and lipid membranes. Both processes leave an intact collagen and elastin structural matrix and preserve the high-strain-rate viscoelastic characteristics of the fresh leaflets. Extraction does cause a 20% reduction in the fracture tension and increases tissue extensibility, with the percent strain at fracture rising to 45.3 +/- 4 (mean +/- SEM) from 31.5 +/- 3 for fresh leaflets. However, extraction does preserve matrix structure and mechanics over the physiological loading range. Glutaraldehyde fixation produces increased extensibility, increased elastic behavior, and, when applied to extracted leaflets, it causes a marked drop in fracture tension, to 50% of that for fresh leaflets. The combination of extraction and fixation may lead to early degenerative failure. The cellular extraction technique alone may be a useful alternative to glutaraldehyde fixation in preparing bioprosthetic heart valves.

  3. The Determination of Some Mechanical Properties of Scheffe's ...

    African Journals Online (AJOL)

    The work determined some mechanical properties of fresh and matured concrete. These properties include Slump, Compressive Strength, Static modulus of elasticity and Modulus of rigidity. It applied Scheffe's optimization theory to determine the ratio of the combined constituents of the concrete mix. The results showed that ...

  4. A simple and rapid infrared-assisted self enzymolysis extraction method for total flavonoid aglycones extraction from Scutellariae Radix and mechanism exploration.

    Science.gov (United States)

    Wang, Liping; Duan, Haotian; Jiang, Jiebing; Long, Jiakun; Yu, Yingjia; Chen, Guiliang; Duan, Gengli

    2017-09-01

    A new, simple, and fast infrared-assisted self enzymolysis extraction (IRASEE) approach for the extraction of total flavonoid aglycones (TFA) mainly including baicalein, wogonin, and oroxylin A from Scutellariae Radix is presented to enhance extraction yield. Extraction enzymolysis temperature, enzymolysis liquid-to-solid ratio, enzymolysis pH, enzymolysis time and infrared power, the factors affecting IRASEE procedure, were investigated in a newly designed, temperature-controlled infrared-assisted extraction (TC-IRAE) system to acquire the optimum analysis conditions. The results illustrated that IRASEE possessed great advantages in terms of efficiency and time compared with other conventional extraction techniques. Furthermore, the mechanism of IRASEE was preliminarily explored by observing the microscopic change of the samples surface structures, studying the main chemical compositions change of the samples before and after extraction and investigating the kinetics and thermodynamics at three temperature levels during the IRASEE process. These findings revealed that IRASEE can destroy the surface microstructures to accelerate the mass transfer and reduce the activation energy to intensify the chemical process. This integrative study presents a simple, rapid, efficient, and environmental IRASEE method for TFA extraction which has promising prospects for other similar herbal medicines. Graphical Abstract ᅟ.

  5. Mechanical properties of irradiated materials

    International Nuclear Information System (INIS)

    Robertson, I.M.; Robach, J.; Wirth, B.

    2001-01-01

    The effect of irradiation on the mechanical properties of metals is considered with particular attention being paid to the development of defect-free channels following uniaxial tensile loading. The in situ transmission electron microscope deformation technique is coupled with dislocation dynamic computer simulations to reveal the fundamental processes governing the elimination of defects by glissile dislocations. The observations of preliminary experiments are reported.(author)

  6. PVA/Polysaccharides Blended Films: Mechanical Properties

    OpenAIRE

    Silva, Fábio E. F.; Di-Medeiros, Maria Carolina B.; Batista, Karla A.; Fernandes, Kátia F.

    2013-01-01

    Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher valu...

  7. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Microstructure and Mechanical Properties of a Laser Treated Al Alloy

    NARCIS (Netherlands)

    Noordhuis, J.; Hosson, J.Th.M. De

    An Al-Cu-Mg alloy, Al 2024-T3, was exposed to laser treatments at various scan velocities. In this paper the microstructural features and mechanical properties are reported. As far as the mechanical property is concerned a striking observation is a minimum in the hardness value at a laser scan

  9. Antioxidant, antinociceptive and anti-inflammatory properties of the aqueous and ethanolic leaf extracts of Andrographis paniculata in some laboratory animals.

    Science.gov (United States)

    Adedapo, Adeolu Alex; Adeoye, Bisi Olajumoke; Sofidiya, Margaret Oluwatoyin; Oyagbemi, Ademola Adetokunbo

    2015-07-01

    The study was designed to evaluate the anti-inflammatory, analgesic and antioxidant properties of Andrographis paniculata leaf extracts in laboratory animals. The dried and powdered leaves of the plant were subjected to phytochemical and proximate analyses. Its mineral content was also determined. Acute toxicity experiments were first performed to determine a safe dose level. The plant material was extracted using water and ethanol as solvents. These extracts were then used to test for the anti-inflammatory, analgesic and antioxidant properties of the plant. The anti-inflammatory tests included carrageenan-induced and histamine-induced paw oedema. The analgesic tests conducted were formalin paw lick test and acetic acid writhing test. The antioxidant activities of the extracts of A. paniculata were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), total polyphenol (TP) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) using ascorbic acid as standard for both DPPH and FRAP, and gallic acid as a standard for both TP and ABTS. The acute toxicity experiment demonstrated that the plant is safe at high doses even at 1600 mg/kg. It was observed that the ethanolic extract of A. paniculata had higher antioxidant activity than the aqueous extract. The experiments using both extracts may suggest that the extracts of A. paniculata leaves possess anti-inflammatory, analgesic and antioxidant properties, although the ethanolic extract seemed to have higher biological properties than the aqueous extract. The results from this study may have justified the plant's folkloric use for medicinal purpose.

  10. Mechanical Properties of a Library of Low-Band-Gap Polymers

    DEFF Research Database (Denmark)

    Roth, Bérenger; Savagatrup, Suchol; de los Santos, Nathaniel V.

    2016-01-01

    The mechanical properties of low-band-gap polymers are important for the long-term survivability of roll to-roll processed organic electronic devices. Such devices, e.g., solar cells, displays, and thin-film transistors, must survive the rigors of roll-to-roll coating and also thermal...... of low-band-gap polymers to better understand the connection between molecular structures and mechanical properties in order to design conjugated polymers that permit mechanical robustness and even extreme deformability. While one of the principal conclusions of these experiments is that the structure...... of an isolated molecule only partially determines the mechanical properties another important codeterminant is the packing structure some general trends can be identified. (1) Fused rings tend to increase the modulus and decrease the ductility. (2) Branched side chains have the opposite effect. Despite...

  11. Kinetic and Thermodynamics studies for Castor Oil Extraction Using Subcritical Water Technology.

    Science.gov (United States)

    Abdelmoez, Wael; Ashour, Eman; Naguib, Shahenaz M; Hilal, Amr; Al Mahdy, Dalia A; Mahrous, Engy A; Abdel-Sattar, Essam

    2016-06-01

    In this work both kinetic and thermodynamics of castor oil extraction from its seeds using subcritical water technique were studied. It was found that the extraction process followed two consecutive steps. In these steps, the oil was firstly extracted from inside the powder by diffusion mechanism. Then the extracted oil, due to extending the extraction time under high temperature and pressure, was subjected to a decomposition reaction following first order mechanism. The experimental data correlated well with the irreversible consecutive unimolecular-type first order mechanism. The values of both oil extraction rate constants and decomposition rate constants were calculated through non-linear fitting using DataFit software. The extraction rate constants were found to be 0.0019, 0.024, 0.098, 0.1 and 0.117 min(-1), while the decomposition rate constants were 0.057, 0.059, 0.014, 0.019 and 0.17 min(-1) at extraction temperatures of 240, 250, 260, 270 and 280°C, respectively. The thermodynamic properties of the oil extraction process were investigated using Arrhenius equation. The values of the activation energy, Ea, and the frequency factor, A, were 73 kJ mol(-1) and 946, 002 min(-1), respectively. The physicochemical properties of the extracted castor oil including the specific gravity, viscosity, acid value, pH value and calorific value were found to be 0.947, 7.487, 1.094 mg KOH/g, 6.1, and 41.5 MJ/Kg, respectively. Gas chromatography analysis showed that ricinoleic acid (83.6%) appears as the predominant fatty acid in the extracted oil followed by oleic acid (5.5%) and linoleic acid (2.3%).

  12. Dynamic Mechanical Properties of PMN/CNFs/EP Composites

    International Nuclear Information System (INIS)

    Shi Minxian; Huang Zhixiong; Qin Yan

    2011-01-01

    In this research, piezoelectric ceramic PMN(lead magnesium niobate-lead zirconate-lead titanate)/carbon nano-fibers(CNFs)/epoxy resin(EP) ccomposites were prepared and the dynamic mechanical properties and damping mechanism of PMN/CNFs/EP composites were investigated. The addition of CNFs into PMN/EP composite results in decrease of volume resistivity of the composite. When the concentration of CNFs is 0.6% weight of epoxy resin the volume resistivity of PMN/CNFs/EP composite is about 10 8 Ω·m. Dynamic mechanical analysis indicates that the loss factor, loss area, and damping temperature range of PMN/CNFs/EP composites increase with the CNFs content increasing till to 0.6% of weight of epoxy resin. When the CNFs content is more than 0.6% the damping properties of composites decrease oppositely. In PMN/CNFs/EP composites, the CNFs content 0.6% and the volume resistivity of PMN/CNFs/EP composites about 10 8 Ω·m just satisfy the practicing condition of piezo-damping, so the composites show optimal damping property.

  13. Long term mechanical properties of alkali activated slag

    Science.gov (United States)

    Zhu, J.; Zheng, W. Z.; Xu, Z. Z.; Leng, Y. F.; Qin, C. Z.

    2018-01-01

    This article reports a study on the microstructural and long-term mechanical properties of the alkali activated slag up to 180 days, and cement paste is studied as the comparison. The mechanical properties including compressive strength, flexural strength, axis tensile strength and splitting tensile strength are analyzed. The results showed that the alkali activated slag had higher compressive and tensile strength, Slag is activated by potassium silicate (K2SiO3) and sodium hydroxide (NaOH) solutions for attaining silicate modulus of 1 using 12 potassium silicate and 5.35% sodium hydroxide. The volume dosage of water is 35% and 42%. The results indicate that alkali activated slag is a kind of rapid hardening and early strength cementitious material with excellent long-term mechanical properties. Single row of holes block compressive strength, single-hole block compressive strength and standard solid brick compressive strength basically meet engineering requirements. The microstructures of alkali activated slag are studied by X-ray diffraction (XRD). The hydration products of alkali-activated slag are assured as hydrated calcium silicate and hydrated calcium aluminate.

  14. Development the Mechanical Properties of (AL-Li-Cu Alloy

    Directory of Open Access Journals (Sweden)

    Ihsan Kadhom AlNaimi

    2017-11-01

    Full Text Available The aim of this research is to develop mechanical properties of a new aluminium-lithium-copper alloy. This alloy prepared under control atmosphere by casting in a permanent metal mould. The microstructure was examined and mechanical properties were tested before and after heat treatment to study the influence of heat treatment on its mechanical properties including; modulus of elasticity, tensile strength, impact, and fatigue. The results showed that the modulus of elasticity of the prepared alloy is higher than standard alloy about 2%. While the alloy that heat treated for 6 h and cooled in water, then showed a higher ultimate tensile stress comparing with as-cast alloy. The homogenous heat treatment gives best fatigue behaviour comparing with as-cast and other heat treatment alloys. Also, the impact test illustrates that the homogeneous heat treatment alloy gives the highest value.

  15. Effects of heat treatment on mechanical properties of h13 steel

    Science.gov (United States)

    Guanghua, Yan; Xinmin, Huang; Yanqing, Wang; Xingguo, Qin; Ming, Yang; Zuoming, Chu; Kang, Jin

    2010-12-01

    Heat treatment on the mechanical properties of H13 hot working die steel for die casting is discussed. The H13 steel for die casting was treated by different temperatures of vacuum quenching, tempering, and secondary tempering to investigate its mechanical properties. Strength, plasticity, hardness, and impact toughness of the H13 hot working die steel for die casting were measured. Microstructure, grain size, and carbide particle size after heat treatment have a great impact on the mechanical properties of H13 hot working die steel for die casting. The microstructure of the H13 was analyzed by scanning electron microscopy (SEM) and by a metallographic microscope. It is found that H13 exhibits excellent mechanical properties after vacuum quenching at 1050°C and twice tempering at 600°C.

  16. Microstructure and mechanical properties of unirradiated low activation ferritic steel

    International Nuclear Information System (INIS)

    Hsu, C.Y.; Lechtenberg, T.A.

    1986-01-01

    Transmission electron micrographs of normalized and tempered 9Cr-2.5W-0.3V-0.15C low activation ferritic steel showed tempered lath-type martensite with precipitation of rod and plate-like carbides at lath and grain boundaries. X-ray diffraction analysis of the extracted replicas revealed nearly 100% M 23 C 6 carbides (a=1.064 nm), with no indication of Fe 2 W-type Laves phase even after thermal aging at 600 0 C/1000 h. Thermal aging increased the number density of rod-like M 23 C 6 along prior austenite grain boundaries and martensite lath boundaries. The elevated-temperature tensile strengths of this steel are about 10% higher than the average strengths of commercial heats of 9Cr-1Mo and modified 9Cr-1Mo steels up to 650 0 C, with equivalent uniform elongation and ∝50% decrease in total elongation. The DBTT was determined to be -25 0 C which is similar to other 9Cr-1Mo steels. Fractographic examination of tensile tested specimens shows a mixed mode of equiaxed and elongated dimples at test temperatures above 400 0 C. Modification of the Ga3X alloy composition for opimization of materials properties is discussed. However, the proposed low activation ferritic steel shows the promise of improved mechanical properties over 9Cr-1Mo steels. (orig.)

  17. Determination of Some Mechanical Properties of Almond Seed ...

    African Journals Online (AJOL)

    Akorede

    I. INTRODUCTION. Information on mechanical properties of agricultural products as a function of moisture content is needed in the design and adjustment of machines used during harvest, separation, cleaning, handling and storage. It is also used in processing these agricultural materials into food. The properties useful for ...

  18. Effect of Caesalpinia sappan L. extract on physico-chemical properties of emulsion-type pork sausage during cold storage.

    Science.gov (United States)

    Jin, Sang-Keun; Ha, So-Ra; Choi, Jung-Seok

    2015-12-01

    This study was performed to investigate the effect of extract from heart wood of Caesalpinia sappan on the physico-chemical properties and to find the appropriate addition level in the emulsion-type pork sausage during cold storage. The pH of treatments with C. sappan extract was significantly lower than control and T1 during cold storage periods (Pextract. Also, the texture properties and sensory of sausages containing C. sappan extract were decreased compared to control. Inclusion of the C. sappan extract in sausages resulted in lower lightness and higher yellowness, chroma and hue values. However, the antioxidant, antimicrobial activity, and volatile basic nitrogen in the emulsion-type pork sausages with C. sappan extract showed increased quality characteristics during cold storage. In conclusion, the proper addition level of C. sappan extract was 0.1% on the processing of emulsion-type pork sausage. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Pharmacological evaluation of anxiolytic property of aqueous root extract of Cymbopogon citratus in mice

    Directory of Open Access Journals (Sweden)

    David Arome

    2014-01-01

    Full Text Available Aim: This study was designed to evaluate the anxiolytic property of aqueous root extract of Cymbopogon citratus in mice. Materials and Methods: In this study, stress induced hyperthermia (SIH, elevated plus maze (EPM and open field experimental models were employed. Results: In SIH model, the extract caused a significant (P 0.05 effect. In open field model, 200 mg/kg and 600 mg/kg extract doses significantly (P < 0.05 increased locomotion of the mice more than the standard, while rearing and defecation were less in the extract groups. Conclusion: In different experimental models used significant anxiolytic effect was observed of the aqueous extract at different dose levels in comparison to reference standard and normal saline group. This clearly justified its folkloric application in the treatment of anxiety disorders.

  20. Measuring Mechanical Properties Of Optical Glasses

    Science.gov (United States)

    Tucker, Dennis S.; Nichols, Ronald L.

    1989-01-01

    Report discusses mechanical tests measuring parameters of strength and fracture mechanics of optical glasses. To obtain required tables of mechanical properties of each glass of interest, both initial-strength and delayed-fracture techniques used. Modulus of rupture measured by well-known four-point bending method. Initial bending strength measured by lesser-known double-ring method, in which disk of glass supported on one face near edge by larger ring and pressed on its other face by smaller concentric ring. Method maximizes stress near center, making it more likely specimen fractures there, and thereby suppresses edge effects. Data from tests used to predict reliabilities and lifetimes of glass optical components of several proposed spaceborne instruments.

  1. Extraction of Water from Polar Lunar Permafrost with Microwaves - Dielectric Property Measurements

    Science.gov (United States)

    Ethridge, Edwin C.; Kaukler, William

    2009-01-01

    Remote sensing indicates the presence of hydrogen rich regions associated with the lunar poles. The logical hypothesis is that there is cryogenically trapped water ice located in craters at the lunar poles. Some of the craters have been in permanent darkness for a billion years. The presence of water at the poles as well as other scientific advantages of a polar base, have influenced NASA plans for the lunar outpost. The lunar outpost has water and oxygen requirements on the order of 1 ton per year scaling up to as much as 10 tons per year. Microwave heating of the frozen permafrost has unique advantages for water extraction. Proof of principle experiments have successfully demonstrated that microwaves will couple to the cryogenic soil in a vacuum and the sublimed water vapor can be successfully captured on a cold trap. The dielectric properties of lunar soil will determine the hardware requirements for extraction processes. Microwave frequency dielectric property measurements of lunar soil simulant have been measured.

  2. Processing and properties of mechanically alloyed sintered steels with hard inclusions

    International Nuclear Information System (INIS)

    Gutsfeld, C.

    1991-10-01

    The aim of this work was the development of mechanically alloyed sintered steels with inert hard inclusions and their characterisation concerning the mechanical properties and the sliding wear behaviour. For this material concept the hard materials NbC, TiC, TiN and Al 2 O 3 were chosen with volume contents upto 20%. Mechanical alloying of the raw powders is a necessary prerequisit for an extreme fine and homogeneous microstructure and good mechanical and wear properties. Through a connecting powder annealing a conventional powder metallurgical processing with cold pressing and sintering is possible. For the consolidation pressureless liquid phase sintering initiated through phosphorus contents of 0,6% is suitable. Because of the strong hampering of grain growth through the included hard particles sintering densities upto 99% TD are possible with extreme fine microstructures. The mechanical properties can be varied in wide ranges. So tensile strengths of 1150 MPa, elongations at fracture of 17%, hardness of over 800 HV and fatigue strengths of 370 MPa have been reached. Throughout HIP or sinter forging the mechanical properties can be improved furthermore. (orig.) [de

  3. Modeling of mechanical properties in alpha/beta-titanium alloys

    Science.gov (United States)

    Kar, Sujoy Kumar

    2005-11-01

    The accelerated insertion of titanium alloys in component application requires the development of predictive capabilities for various aspects of their behavior, for example, phase stability, microstructural evolution and property-microstructure relationships over a wide range of length and time scales. In this presentation some navel aspects of property-microstructure relationships and microstructural evolution in alpha/beta Ti alloys will be discussed. Neural Network (NN) Models based on a Bayesian framework have been developed to predict the mechanical properties of alpha/beta Ti alloys. The development of such rules-based model requires the population of extensive databases, which in the present case are microstructurally-based. The steps involved in database development include producing controlled variations of the microstructure using novel approaches to heat-treatments, the use of standardized stereology protocols to characterize and quantify microstructural features rapidly, and mechanical testing of the heat-treated specimens. These databases have been used to train and test NN Models for prediction of mechanical properties. In addition, these models have been used to identify the influence of individual microstructural features on the mechanical properties, consequently guiding the efforts towards development of more robust mechanistically based models. In order to understand the property-microstructure relationships, a detailed understanding of microstructure evolution is imperative. The crystallography of the microstructure developing as a result of the solid-state beta → beta+alpha transformation has been studied in detail by employing Scanning Electron Microscopy (SEM), Orientation Imaging Microscopy (in a high resolution SEM), site-specific TEM sample preparation using focused ion beam, and TEM based techniques. The influence of variant selection on the evolution of microstructure will be specifically addressed.

  4. Predicting Silk Fiber Mechanical Properties through Multiscale Simulation and Protein Design.

    Science.gov (United States)

    Rim, Nae-Gyune; Roberts, Erin G; Ebrahimi, Davoud; Dinjaski, Nina; Jacobsen, Matthew M; Martín-Moldes, Zaira; Buehler, Markus J; Kaplan, David L; Wong, Joyce Y

    2017-08-14

    Silk is a promising material for biomedical applications, and much research is focused on how application-specific, mechanical properties of silk can be designed synthetically through proper amino acid sequences and processing parameters. This protocol describes an iterative process between research disciplines that combines simulation, genetic synthesis, and fiber analysis to better design silk fibers with specific mechanical properties. Computational methods are used to assess the protein polymer structure as it forms an interconnected fiber network through shearing and how this process affects fiber mechanical properties. Model outcomes are validated experimentally with the genetic design of protein polymers that match the simulation structures, fiber fabrication from these polymers, and mechanical testing of these fibers. Through iterative feedback between computation, genetic synthesis, and fiber mechanical testing, this protocol will enable a priori prediction capability of recombinant material mechanical properties via insights from the resulting molecular architecture of the fiber network based entirely on the initial protein monomer composition. This style of protocol may be applied to other fields where a research team seeks to design a biomaterial with biomedical application-specific properties. This protocol highlights when and how the three research groups (simulation, synthesis, and engineering) should be interacting to arrive at the most effective method for predictive design of their material.

  5. Mechanical properties and corrosion behaviour of MIG welded 5083 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Durmus, Huelya [Celal Bayar Univ., Turgutlu-Manisa (Turkey)

    2011-07-01

    For this study 5083 Aluminium alloy plates, as used in automobiles and watercraft, were experimentally MIG welded. The plates were joined with different wires and at various currents. The effects of welding with different parameters on the mechanical and corrosion properties were investigated. The corrosion behaviour of the MIG welded 5083 Aluminium base material was also investigated. The effects of the chemical composition of the filler material on the mechanical properties were examined by metallographic inspection and tensile testing. By EDS and XRD analyses of specimens it turned out that different structures in the weld metal (Cu3Si) affect its mechanical properties. The mechanical properties of the specimens welded with 5356 filler metal were found as quite well improved as compared to those specimens welded with 4043 and 5183 filler material. The results of the metallographic analysis, and mechanical and corrosion tests exhibited that the 5356 filler material was most suitable for the 5083 Al alloy base material. (orig.)

  6. Chemical characteristic and functional properties of arenga starch-taro (Colocasia esculanta L.) flour noodle with turmeric extracts addition

    Science.gov (United States)

    Ervika Rahayu N., H.; Ariani, Dini; Miftakhussolikhah, E., Maharani P.; Yudi, P.

    2017-01-01

    Arenga starch-taro (Colocasia esculanta L.) flour noodle is an alternative carbohydrate source made from 75% arenga starch and 25% taro flour, but it has a different color with commercial noodle product. The addition of natural color from turmeric may change the consumer preference and affect chemical characteristic and functional properties of noodle. This research aims to identify chemical characteristic and functional properties of arenga starch-taro flour noodle with turmeric extract addition. Extraction was performed using 5 variances of turmeric rhizome (0.06; 0.12; 0.18; 0.24; and 0.30 g (fresh weight/ml water). Then, noodle was made and chemical characteristic (proximate analysis) as well as functional properties (amylose, resistant starch, dietary fiber, antioxidant activity) were then evaluated. The result showed that addition of turmeric extract did not change protein, fat, carbohydrate, amylose, and resistant starch content significantly, while antioxidant activity was increased (23,41%) with addition of turmeric extract.

  7. Estimating the mechanical properties of the brittle deformation zones at Olkiluoto

    International Nuclear Information System (INIS)

    Hudson, J.A.; Cosgrove, J.W.; Johansson, E.

    2008-09-01

    In rock mechanics modelling to support repository design and safety assessment for the Olkiluoto site, it is necessary to obtain the relevant rock mechanics parameters, these being an essential pre-requisite for the modelling. The parameters include the rock stress state, the properties of the intact rock and the rock mass, and the properties of the brittle deformation zones which represent major discontinuities in the rock mass continuum. However, because of the size and irregularity of the brittle deformation zones, it is not easy to estimate their mechanical properties, i.e. their deformation and strength properties. Following Section 1 explaining the motivation for the work and the objective of the Report, in Sections 2 and 3, the types of fractures and brittle deformation zones that can be encountered are described with an indication of the mechanisms that lead to complex structures. The geology at Olkiluoto is then summarized in Section 4 within the context of this Report. The practical aspects of encountering the brittle deformation zones in outcrops, drillholes and excavations are described in Sections 5 and 6 with illustrative examples of drillhole core intersections in Section 7. The various theoretical, numerical and practical methods for estimating the mechanical properties of the brittle deformation zones are described in Section 8, together with a Table summarizing each method's advantages, disadvantages and utility in estimating the mechanical properties of the zones. We emphasise that the optimal approach to estimating the mechanical properties of the brittle deformation zones cannot be determined without a good knowledge, not only of each estimation method's capabilities and idiosyncrasies, but also of the structural geology background and the specific nature of the brittle deformation zones being characterized. Finally, in Section 9, a Table is presented outlining each method's applicability to the Olkiluoto site. A flowchart is included to

  8. Mechanical Properties of Additively Manufactured Thick Honeycombs

    Directory of Open Access Journals (Sweden)

    Reza Hedayati

    2016-07-01

    Full Text Available Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D tessellated structures such as porous biomaterials. In this paper, we study the mechanical behavior of thick honeycombs made using additive manufacturing techniques that allow for fabrication of honeycombs with arbitrary and precisely controlled thickness. Thick honeycombs with different wall thicknesses were produced from polylactic acid (PLA using fused deposition modelling, i.e., an additive manufacturing technique. The samples were mechanically tested in-plane under compression to determine their mechanical properties. We also obtained exact analytical solutions for the stiffness matrix of thick hexagonal honeycombs using both Euler-Bernoulli and Timoshenko beam theories. The stiffness matrix was then used to derive analytical relationships that describe the elastic modulus, yield stress, and Poisson’s ratio of thick honeycombs. Finite element models were also built for computational analysis of the mechanical behavior of thick honeycombs under compression. The mechanical properties obtained using our analytical relationships were compared with experimental observations and computational results as well as with analytical solutions available in the literature. It was found that the analytical solutions presented here are in good agreement with experimental and computational results even for very thick honeycombs, whereas the analytical solutions available in the literature show a large deviation from experimental observation, computational results, and our analytical solutions.

  9. An Investigation into the Physico-chemical Properties of Transformer Oil Blends with Antioxidants extracted from Turmeric Powder

    Science.gov (United States)

    Dukhi, Veresha; Bissessur, Ajay; Ngila, Catherine Jane; Ijumba, Nelson Mutatina

    2013-07-01

    The blending of transformer oil (used mainly as an insulating oil) with appropriate synthetic antioxidants, such as BHT (2,6-di-tert-butyl-4-methylphenol) and DBP (2,6-di-tert-butylphenol) have been previously reported. This article is focused on the use of antioxidant extracts from turmeric (Curcuma longa), a natural source. Turmeric is well known for its antimicrobial, antioxidant and anticarcinogenic properties owing to the active nature of its components. Extracts from powdered turmeric were subsequently blended into naphthenic-based uninhibited virgin transformer oil, hereinafter referred to as extract-oil blends (E-OB). Thin-layer chromatography (TLC) of the oil blends revealed that five components extracted from turmeric powder were successfully blended into the oil. Subsequent gas chromatography-mass spectrometry (GC-MS) analysis confirmed the presence of the compounds: curcumene, sesquiphellandrene, ar-turmerone, turmerone and curlone. Thermogravimetric analysis (TGA) of the extract-oil blends, containing various levels of extracts, revealed an average temperature shift of ˜8.21°C in the initial onset of degradation in comparison to virgin non-blended oil. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay showed that an increase in the mass aliquot of turmeric extracts in the transformer oil increased the free radical scavenging activity of the oil. Electrical properties of the oil investigated showed that the dissipation factor in the blended oil was found to be lower than that of virgin transformer oil. Evidently, a lower dissipation value renders the oil blend as a superior insulator over normal virgin non-blended oil. This investigation elucidated improved physico-chemical properties of transformer oil blended with turmeric antioxidant extracts.

  10. Mechanical properties of jennite: A theoretical and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2015-05-15

    The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.

  11. An Introduction to the Mechanical Properties of Ceramics

    Science.gov (United States)

    Green, David J.

    1998-09-01

    Over the past twenty-five years ceramics have become key materials in the development of many new technologies as scientists have been able to design these materials with new structures and properties. An understanding of the factors that influence their mechanical behavior and reliability is essential. This book will introduce the reader to current concepts in the field. It contains problems and exercises to help readers develop their skills. This is a comprehensive introduction to the mechanical properties of ceramics, and is designed primarily as a textbook for advanced undergraduates in materials science and engineering. It will also be of value as a supplementary text for more general courses and to industrial scientists and engineers involved in the development of ceramic-based products, materials selection and mechanical design.

  12. Microstructure and mechanical properties of as-cast Zr-Nb alloys.

    Science.gov (United States)

    Kondo, Ryota; Nomura, Naoyuki; Suyalatu; Tsutsumi, Yusuke; Doi, Hisashi; Hanawa, Takao

    2011-12-01

    On the basis of the microstructures and mechanical properties of as-cast Zr-(0-24)Nb alloys the effects of phase constitution on the mechanical properties and magnetic susceptibility are discussed in order to develop Zr alloys for use in magnetic resonance imaging (MRI). The microstructures were evaluated using an X-ray diffractometer, an optical microscope, and a transmission electron microscope; the mechanical properties were evaluated by a tensile test. The α' phase was dominantly formed with less than 6 mass% Nb content. The ω phase was formed in Zr-(6-20)Nb alloys, but disappeared from Zr-22Nb. The β phase dominantly existed in Zr-(9-24)Nb alloys. The mechanical properties as well as the magnetic susceptibility of the Zr-Nb alloys varied depending on the phase constitution. The Zr-Nb alloys consisting of mainly α' phase showed high strength, moderate ductility, and a high Young's modulus, retaining low magnetic susceptibility. Zr-Nb alloys containing a larger volume of ω phase were found to be brittle and, thus, should be avoided, despite their low magnetic susceptibility. When the Zr-Nb alloys consisted primarily of β phase the effect of ω phase weakened the mechanical properties, thereby leading to an increase in ductility, even with an increase in magnetic susceptibility. The minimum value of Young's modulus was obtained for Zr-20Nb, because this composition was the phase boundary between the β and ω phases. However, the magnetic susceptibility of the alloy was half that of Ti-6Al-4V alloys. Zr-Nb alloys consisting of α' or β phase have excellent mechanical properties with low magnetic susceptibility and, thus, these alloys could be useful for medical devices used in MRI. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. Influence of tempering temperature on mechanical properties of cast steels

    Directory of Open Access Journals (Sweden)

    G. Golański

    2008-12-01

    Full Text Available The paper presents results of research on the influence of tempering temperature on structure and mechanical properties of bainite hardened cast steel: G21CrMoV4 – 6 (L21HMF and G17CrMoV5 – 10 (L17HMF. Investigated cast steels were taken out from internal frames of steam turbines serviced for long time at elevated temperatures. Tempering of the investigated cast steel was carried out within the temperature range of 690 ÷ 730 C (G21CrMoV4 – 6 and 700 ÷ 740 C (G17CrMoV5 – 10. After tempering the cast steels were characterized by a structure of tempered lower bainite with numerous precipitations of carbides. Performed research of mechanical properties has shown that high temperatures of tempering of bainitic structure do not cause decrease of mechanical properties beneath the required minimum.oo It has also been proved that high-temperature tempering (>720 oC ensures high impact energy at the 20% decrease of mechanical properties.

  14. Phase imaging of mechanical properties of live cells (Conference Presentation)

    Science.gov (United States)

    Wax, Adam

    2017-02-01

    The mechanisms by which cells respond to mechanical stimuli are essential for cell function yet not well understood. Many rheological tools have been developed to characterize cellular viscoelastic properties but these typically require direct mechanical contact, limiting their throughput. We have developed a new approach for characterizing the organization of subcellular structures using a label free, noncontact, single-shot phase imaging method that correlates to measured cellular mechanical stiffness. The new analysis approach measures refractive index variance and relates it to disorder strength. These measurements are compared to cellular stiffness, measured using the same imaging tool to visualize nanoscale responses to flow shear stimulus. The utility of the technique is shown by comparing shear stiffness and phase disorder strength across five cellular populations with varying mechanical properties. An inverse relationship between disorder strength and shear stiffness is shown, suggesting that cell mechanical properties can be assessed in a format amenable to high throughput studies using this novel, non-contact technique. Further studies will be presented which include examination of mechanical stiffness in early carcinogenic events and investigation of the role of specific cellular structural proteins in mechanotransduction.

  15. Effect of extraction methods on property and bioactivity of water-soluble polysaccharides from Amomum villosum.

    Science.gov (United States)

    Yan, Yajuan; Li, Xia; Wan, Mianjie; Chen, Jingping; Li, Shijie; Cao, Man; Zhang, Danyan

    2015-03-06

    In the present study, effect of different extraction methods on property and bioactivity of water-soluble polysaccharides (WSP) from the seeds of Amomum villosum were investigated. Firstly, four different extraction methods were used to extract WSP, which include hot water extraction (HWE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE) and enzyme-assisted extraction (EAE). As a result, four WSP samples, WSP(H), WSP(U), WSP(M) and WSP(E) were acquired. Then, the difference of four WSP samples in yield, characterization and antioxidant activities in vitro were further compared. Experimental results showed that the four WSP samples had the same monosaccharide composition, but mere difference in the content; they all had typical IR spectra characteristic of polysaccharides. WSP(U) contained the highest contents of uronic acid and sulfate. The yield of WSP(U) was the highest and its antioxidant activity was the best. These results suggested that ultrasonic-assisted extraction was the best extraction method for WSP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Improved mechanical properties of retorted carrots by ultrasonic pre-treatments.

    Science.gov (United States)

    Day, Li; Xu, Mi; Øiseth, Sofia K; Mawson, Raymond

    2012-05-01

    The use of ultrasound pre-processing treatment, compared to blanching, to enhance mechanical properties of non-starchy cell wall materials was investigated using carrot as an example. The mechanical properties of carrot tissues were measured by compression and tensile testing after the pre-processing treatment prior to and after retorting. Carrot samples ultrasound treated for 10 min at 60 °C provided a higher mechanical strength (P<0.05) to the cell wall structure than blanching for the same time period. With the addition of 0.5% CaCl(2) in the pre-treatment solution, both blanching and ultrasound treatment showed synergistic effect on enhancing the mechanical properties of retorted carrot pieces. At a relatively short treatment time (10 min at 60 °C) with the use of 0.5% CaCl(2), ultrasound treatment achieved similar enhancement to the mechanical strength of retorted carrots to blanching for a much longer time period (i.e. 40 min). The mechanism involved appears to be related to the stress responses present in all living plant matter. However, there is a need to clarify the relative importance of the potential stress mechanisms in order to get a better understanding of the processing conditions likely to be most effective. The amount of ultrasound treatment required is likely to involve low treatment intensities and there are indications from the structural characterisation and mechanical property analyses that the plant cell wall tissues were more elastic than that accomplished using low temperature long time blanching. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  17. Neuroprotective and neurochemical properties of mint extracts

    DEFF Research Database (Denmark)

    López, Víctor; Martín, Sara; Gómez-Serranillos, Maria Pilar

    2010-01-01

    (A) receptor). Mentha x piperita and Mentha aquatica produced significant (p oxidative stress. All the plants exhibited antioxidant and MAO-A inhibitory activities, M. x piperita being the most active. M. aquatica showed the highest affinity to the GABA......Mints are aromatic plants with a tradition as medicinal remedies and culinary herbs. With the aim of investigating potential central nervous system (CNS) activities of traditional medicinal plants, four species and one hybrid of the genus Mentha (M. aquatica, M. longifolia, M. pulegium, M....... suaveolens and M. x piperita) were selected. Methanolic extracts of the plants were tested for protective effects against hydrogen-peroxide-induced toxicity in PC12 cells, antioxidant activity (by ABTS and X/XO methods) and neurochemical properties (MAO-A inhibition, AChE inhibition and affinity to the GABA...

  18. The effect of thermo-mechanical processing on the mechanical properties of molybdenum - 2 volume % lanthana

    International Nuclear Information System (INIS)

    Mueller, A.J.; Shields, J.A. Jr.; Buckman, R.W. Jr.

    2001-01-01

    Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 volume % La 2 O 3 mill product forms, produced by CSM Industries by a wet doping process, were characterized over the temperature range of -150 o C to 1800 o C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved .material had superior creep rupture properties to recrystallized material at 1200 o C, while at 1500 o C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % La 2 O 3 to the demands of the application being considered. (author)

  19. Characterization of mechanical properties and microstructure of highly irradiated SS 316

    Energy Technology Data Exchange (ETDEWEB)

    Karthik, V., E-mail: karthik@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Kumar, RanVijay; Vijayaragavan, A.; Venkiteswaran, C.N.; Anandaraj, V.; Parameswaran, P.; Saroja, S.; Muralidharan, N.G.; Joseph, Jojo; Kasiviswanathan, K.V.; Jayakumar, T.; Raj, Baldev [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2013-08-15

    Cold worked austenitic stainless steel type AISI 316 is used as the material for fuel cladding and wrapper of the Fast Breeder Test Reactor (FBTR), India. The evaluation of mechanical properties of these core structurals is very essential to assess its integrity and ensure safe and productive operation of FBTR to very high burn-ups. The changes in the mechanical properties of these core structurals are associated with microstructural changes caused by high fluence neutron irradiation and temperatures of 673–823 K. Remote tensile testing has been used for evaluating the tensile properties of irradiated clad tubes and shear punch test using small disk specimens for evaluating the properties of irradiated hexagonal wrapper. This paper will highlight the methods employed for evaluating the mechanical properties of the irradiated cladding and wrapper and discuss the trends in properties as a function of dpa (displacement per atom) and irradiation temperature.

  20. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.; Aldhahri, Musab A.; Abdel-wahab, Mohamed Shaaban; Tamayol, Ali; Moghaddam, K. Mollazadeh; Ben Rached, Fathia; Pain, Arnab; Khademhosseini, Ali; Memic, Adnan; Chaieb, Saharoui

    2017-01-01

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  1. Microfibrous silver-coated polymeric scaffolds with tunable mechanical properties

    KAUST Repository

    Kalakonda, Parvathalu.

    2017-07-07

    Electrospun scaffolds of poly(glycerol sebacate)/poly(ε-caprolactone) (PGS/PCL) have been used for engineered tissues due to their desirable thermal and mechanical properties as well as their tunable degradability. In this paper, we fabricated micro-fibrous scaffolds from a composite of PGS/PCL using a standard electrospinning method and coated them with silver (Ag). The low temperature coating method prevented substrate melting and the Ag coating decreases the pore size and increases the diameter of fibers which resulted in enhanced thermal and mechanical properties. We further compared the mechanical properties of the composite fibrous scaffolds with different thicknesses of Ag coated scaffolds. The composite fibrous scaffold with a 275 nm Ag coating showed higher tensile modulus (E) and ultimate tensile strength (UTS) without any post-processing treatment. Lastly, potential controlled release of the Ag coating from the composite fibrous scaffolds could present interesting biomedical applications.

  2. Effects of humidity on the mechanical properties of gecko setae.

    Science.gov (United States)

    Prowse, Michael S; Wilkinson, Matt; Puthoff, Jonathan B; Mayer, George; Autumn, Kellar

    2011-02-01

    We tested the hypothesis that an increase in relative humidity (RH) causes changes in the mechanical properties of the keratin of adhesive gecko foot hairs (setae). We measured the effect of RH on the tensile deformation properties, fracture, and dynamic mechanical response of single isolated tokay gecko setae and strips of the smooth lamellar epidermal layer. The mechanical properties of gecko setae were strongly affected by RH. The complex elastic modulus (measured at 5 Hz) of a single seta at 80% RH was 1.2 GPa, only 39% of the value when dry. An increase in RH reduced the stiffness and increased the strain to failure. The loss tangent increased significantly with humidity, suggesting that water absorption produces a transition to a more viscous type of deformation. The influence of RH on the properties of the smooth epidermal layer was comparable with that of isolated seta, with the exception of stress at rupture. These values were two to four times greater for the setae than for the smooth layer. The changes in mechanical properties of setal keratin were consistent with previously reported increases in contact forces, supporting the hypothesis that an increase in RH softens setal keratin, which increases adhesion and friction. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Mechanical and physical properties of agro-based fiberboard

    Science.gov (United States)

    S. Lee; T.F. Shupe; C.Y. Hse

    2006-01-01

    In order to better utilize agricultural fibers as an alternative resource for composite panels, several variables were investigated to improve mechanical and physical properties of agm-based fiberboard. This study focused on the effect of fiber morphology, slenderness ratios (UD), and fiber mixing combinations on panel properties. The panel construction types were also...

  4. Mechanical Properties and Tensile Fatigue of Graphene Nanoplatelets Reinforced Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Shen

    2013-01-01

    Full Text Available Graphene nanoplatelets (GNPs are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, GNPs were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical properties of GNPs/epoxy nanocomposite, such as ultimate tensile strength and flexure properties, were investigated. The fatigue life of epoxy/carbon fiber composite laminate with GPs-added 0.25 wt% was increased over that of neat laminates at all levels of cyclic stress. Consequently, significant improvement in the mechanical properties of ultimate tensile strength, flexure, and fatigue life was attained for these epoxy resin composites and carbon fiber-reinforced epoxy composite laminates.

  5. Effect of crystallinity and plasticizer on mechanical properties and tissue integration of starch-based materials from two botanical origins.

    Science.gov (United States)

    Velasquez, Diego; Pavon-Djavid, Graciela; Chaunier, Laurent; Meddahi-Pellé, Anne; Lourdin, Denis

    2015-06-25

    The application of starch-based materials for biomedical purposes has attracted significant interest due to their biocompatibility. The physical properties and crystal structure of materials based on potato starch (PS) and amylomaize starch (AMS) were studied under physiological conditions. PS plasticized with 20% glycerol presented the best mechanical properties with an elastic modulus of 1.6MPa and a weak swelling, remaining stable for 30 days. The in vitro cell viability of 3T3 cells after contact with extracts from PS and AMS with 20% glycerol is 72% and 80%, respectively. PS presented good tissue integration and no significant inflammation or foreign body response after 30 days intra-muscular implantation in a rat model, contrary to AMS. It was shown that glycerol plasticization favors a fast B-type crystallization of PS materials, enhancing their mechanical strength and durability, and making them a good candidate for bioresorbable and biocompatible materials for implantable medical devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Cold forging stem of total hip prosthesis with hybrid mechanical properties

    International Nuclear Information System (INIS)

    Lopes, E.S.N.; Contieri, R.J.; Cardoso, F.F.; Cremasco, A.; Button, S.T.; Caram, R.

    2010-01-01

    Type β Ti alloy is one of the most versatile groups of materials with regard to mechanical properties. Aspects such as alloying elements selection, mechanical processing and heat treatment routes empower these materials in applications where hybrid mechanical behavior is necessary. The aim of this study is to produce stems of total hip prostheses with hybrid mechanical properties using Ti-Nb alloys. Ingots were produced by using arc melting. Following, samples were subjected to specific heat treatment aiming to make cold forging. Sample characterization includes X-ray diffraction, scanning electron microscopy, Vickers hardness tests and tensile test. The experiments performed allowed to examine the effects of heat treatment parameters on the microstructure and mechanical behavior. Finally, results obtained show that the application of specific heat treatments of quenching and aging makes feasible the manufacturing of orthopedic devices with hybrid mechanical properties with regions where high mechanical strength was prioritized, while in others, low elastic modulus was the main concern. (author)

  7. Retrogradation of concentrated starch systems : mechanism and consequences for product properties

    NARCIS (Netherlands)

    Keetels, C.J.A.M.

    1995-01-01

    The mechanical properties of concentrated starch + water systems were studied during heating, cooling and storage. Methods used were a small-amplitude dynamic rheological test and compression between parallel plates. The mechanical properties were related to the structure of the gels.

  8. Reduced left ventricular filling following blood volume extraction does not result in compensatory augmentation of cardiac mechanics.

    Science.gov (United States)

    Lord, Rachel; MacLeod, David; George, Keith; Oxborough, David; Shave, Rob; Stembridge, Mike

    2018-04-01

    What is the central question of this study? A reduction in left ventricular (LV) filling, and concomitant increase in heart rate, augments LV mechanics to maintain stroke volume (SV); however, the impact of reduced LV filling in isolation on SV and LV mechanics is currently unknown. What is the main finding and its importance? An isolated decrease in LV filling did not provoke a compensatory increase in mechanics to maintain SV; in contrast, LV mechanics and SV were reduced. These data indicate that when LV filling is reduced without changes in heart rate, LV mechanics do not compensate to maintain SV. An acute non-invasive reduction in preload has been shown to augment cardiac mechanics to maintain stroke volume and cardiac output. Such interventions induce concomitant changes in heart rate, whereas blood volume extraction reduces preload without changes in heart rate. Therefore, the purpose of this study was to determine whether a preload reduction in isolation resulted in augmented stroke volume achieved via enhanced cardiac mechanics. Nine healthy volunteers (four female, age 29 ± 11 years) underwent echocardiography for the assessment of left ventricular (LV) volumes and mechanics in a supine position at baseline and end extraction after the controlled removal of 25% of total blood volume (1062 ± 342 ml). Arterial blood pressure was monitored continuously by a pressure transducer attached to an indwelling radial artery catheter. Heart rate and total peripheral resistance were unchanged from baseline to end extraction, but systolic blood pressure was reduced (from 148 to 127 mmHg). From baseline to end extraction there were significant reductions in left ventricular end-diastolic volume (from 89 to 71 ml) and stroke volume (from 56 to 37 ml); however, there was no change in LV twist, basal or apical rotation. In contrast, LV longitudinal strain (from -20 to -17%) and basal circumferential strain (from -22 to -19%) were significantly reduced from

  9. Enhancement in insulation and mechanical properties of PMMA nanocomposite foams infused with multi-walled carbon nanotubes.

    Science.gov (United States)

    Yeh, Jui-Ming; Chang, Kung-Chin; Peng, Chih-Wei; Lai, Mei-Chun; Hwang, Shyh-Shin; Lin, Hong-Ru; Liou, Shir-Joe

    2011-08-01

    In this study, PMMA/CNTs composite materials with carboxyl-multi walled carbon nanotubes (c-MWNTs) or untreated MWNTs were prepared via in-situ bulk polymerization. The as-prepared PMMA/CNTs composite materials were then characterized by Fourier-Transformation infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The molecular weights of PMMA extracted from PMMA/CNTs composite materials and bulk PMMA were determined by gel permeation chromatography (GPC) with THF used as the eluant. The PMMA/CNTs composite materials were used to produce foams by a batch process in an autoclave using nitrogen as foaming agent. The cellular microstructure, insulation and compressive mechanical properties of PMMA/CNTs composite foams were also investigated in detail. Compared to neat PMMA foam, the presence of CNTs increases in cell density and reduces cell size. The insulation and compressive mechanical properties of PMMA/CNTs composite foams were found to improve substantially those of neat PMMA foam. In particular, 22.6% decrease in thermal conductivity, 19.7% decrease in dielectric constant and 160% increase in compressive modulus were observed with the addition of 0.3 wt% carboxyl-multi walled carbon nanotubes (c-MWNTs).

  10. Mechanical properties of amyloid-like fibrils defined by secondary structures

    Science.gov (United States)

    Bortolini, C.; Jones, N. C.; Hoffmann, S. V.; Wang, C.; Besenbacher, F.; Dong, M.

    2015-04-01

    Amyloid and amyloid-like fibrils represent a generic class of highly ordered nanostructures that are implicated in some of the most fatal neurodegenerative diseases. On the other hand, amyloids, by possessing outstanding mechanical robustness, have also been successfully employed as functional biomaterials. For these reasons, physical and chemical factors driving fibril self-assembly and morphology are extensively studied - among these parameters, the secondary structures and the pH have been revealed to be crucial, since a variation in pH changes the fibril morphology and net chirality during protein aggregation. It is important to quantify the mechanical properties of these fibrils in order to help the design of effective strategies for treating diseases related to the presence of amyloid fibrils. In this work, we show that by changing pH the mechanical properties of amyloid-like fibrils vary as well. In particular, we reveal that these mechanical properties are strongly related to the content of secondary structures. We analysed and estimated the Young's modulus (E) by comparing the persistence length (Lp) - measured from the observation of TEM images by using statistical mechanics arguments - with the mechanical information provided by peak force quantitative nanomechanical property mapping (PF-QNM). The secondary structure content and the chirality are investigated by means of synchrotron radiation circular dichroism (SR-CD). Results arising from this study could be fruitfully used as a protocol to investigate other medical or engineering relevant peptide fibrils.Amyloid and amyloid-like fibrils represent a generic class of highly ordered nanostructures that are implicated in some of the most fatal neurodegenerative diseases. On the other hand, amyloids, by possessing outstanding mechanical robustness, have also been successfully employed as functional biomaterials. For these reasons, physical and chemical factors driving fibril self-assembly and morphology

  11. Effect of Titanium on the Microstructure and Mechanical Properties of High-Carbon Martensitic Stainless Steel 8Cr13MoV

    Directory of Open Access Journals (Sweden)

    Wen-Tao Yu

    2016-08-01

    Full Text Available The effect of titanium on the carbides and mechanical properties of martensitic stainless steel 8Cr13MoV was studied. The results showed that TiCs not only acted as nucleation sites for δ-Fe and eutectic carbides, leading to the refinement of the microstructure, but also inhibited the formation of eutectic carbides M7C3. The addition of titanium in steel also promoted the transformation of M7C3-type to M23C6-type carbides, and consequently more carbides could be dissolved into the matrix during hot processing as demonstrated by the determination of extracted carbides from the steel matrix. Meanwhile, titanium suppressed the precipitation of secondary carbides during annealing. The appropriate amount of titanium addition decreased the size and fraction of primary carbides in the as-cast ingot, and improved the mechanical properties of the annealed steel.

  12. Extraction mechanism of U(VI) ions by N,N-dialkylamides

    International Nuclear Information System (INIS)

    Descouls, N.; Musikas, C.

    1985-09-01

    N,N dialkylamides are good extractants of UO 2 2+ ions from the nitric solutions obtained on dissolution of nuclear irradiated fuels. The extraction mechanism of U(VI) ions proved to be rather complex. Two species were identified by spectrophotometry in the organic phase: UO 2 (NO 3 ) 2 L 2 (1) and UO 2 (NO 3 ) 3 HL (2), L standing for the amide molecule. The complex (1) is typical for neutral molecules extractants. However, when log D(U(VI)) is plotted against log C (amide), the slope of the straight line obtained is greater than 2, which suggests that amide (1) interactions take place in the 2sup(nd) coordination sphere of U(VI) ions. The crystal structure of (1) where L is the N,N-di-n-butyldodecanamide show that Van der Waals interactions occur between the dodecyl chains of two (1) molecules. The complex (2) is characteristic for anionic extractants. For the amide molecules studied, it takes place in very acidic media. In order to investigate the nature of the UO 2 (NO 3 ) 3 HL complex, the infra-red shift of νc=0 vibration were compared in the following compounds: free amide, HNO 3 - L, phenol L, UO 2 (NO 3 ) 3 HL. The results are discussed. 14 refs [fr

  13. PHYSICAL AND MECHANICAL PROPERTIES OF JUVENILE Schizolobium amazonicum WOOD

    Directory of Open Access Journals (Sweden)

    Graziela Baptista Vidaurre

    2018-03-01

    Full Text Available ABSTRACT Growth in world demand for wood implies a search for new fast growing species with silvicultural potential, and in this scenario for native species such as Paricá . Thus, the objective of this study was determining the physical and mechanical wood properties of the Schizolobium amazonicum species (known as Paricá in Brazil. Trees were collected from commercial plantations located in the north of Brazil with ages of 5, 7, 9 and 11 years. Four logs from trees of each age in the longitudinal direction of the trees were obtained, and later a diametrical plank of each log was taken to manufacture the specimens which were used to evaluate some physical and mechanical properties of the wood. The basic density of Paricá was reduced in the basetop direction and no difference between the radial positions was observed, while the average basic density of this wood was characterized as low. The region close to the bark showed less longitudinal contraction and also greater homogeneity of this property along the trunk, while for tangential contraction the smallest variation was found in the region near the pith. Paricá wood contraction was characterized as low. Age influenced most of the mechanical properties, where logs from the base had the highest values of mechanical strength.

  14. Anti-Hyperglycemic Properties of Crude Extract and Triterpenes from Poria cocos

    Directory of Open Access Journals (Sweden)

    Tzu-Hsuan Li

    2011-01-01

    Full Text Available Poria cocos, Bai Fu Ling in Chinese, is used in traditional Chinese medicine to treat diabetes. However, its claimed benefits and mechanism are not fully understood. This study aimed to investigate the effect and action of P. cocos on type 2 diabetes. We first performed phytochemical analysis on the crude extract and factions of P. cocos. P. cocos crude extract at 50 mg/kg body weight or more significantly decreased blood glucose levels in db/db mice. Based on a bioactivity-directed fractionation and isolation (BDFI strategy, chloroform fraction and subfractions 4 and 6 of the P. cocos crude extract possessed a blood glucose-lowering effect. Dehydrotumulosic acid, dehydrotrametenolic acid, and pachymic acid were identified from the chloroform sub-fractions 4, 3, and 2, respectively. Dehydrotumulosic acid had anti-hyperglycemic effect to a greater extent than dehydrotrametenolic acid and pachymic acid. Mechanistic study on streptozocin- (STZ- treated mice showed that the crude extract, dehydrotumulosic acid, dehydrotrametenolic acid, and pachymic acid of P. cocos exhibited different levels of insulin sensitizer activity. However, the P. cocos crude extract and triterpenes appeared not to activate PPAR-γ pathway. Overall, the data suggest that the P. cocos extract and its triterpenes reduce postprandial blood glucose levels in db/db mice via enhanced insulin sensitivity irrespective of PPAR-γ.

  15. Mechanical properties of open-cell metallic biomaterials manufactured using additive manufacturing

    International Nuclear Information System (INIS)

    Campoli, G.; Borleffs, M.S.; Amin Yavari, S.; Wauthle, R.; Weinans, H.; Zadpoor, A.A.

    2013-01-01

    Highlights: ► Finite element (FE) models were used to predict the mechanical properties of porous biomaterials. ► Porous materials were produced using additive manufacturing techniques. ► Manufacturing irregularities need to be implemented in FE models. ► FE models are more accurate than analytical models in predicting mechanical properties. - Abstract: An important practical problem in application of open-cell porous biomaterials is the prediction of the mechanical properties of the material given its micro-architecture and the properties of its matrix material. Although analytical methods can be used for this purpose, these models are often based on several simplifying assumptions with respect to the complex architecture and cannot provide accurate prediction results. The aim of the current study is to present finite element (FE) models that can predict the mechanical properties of porous titanium produced using selective laser melting or selective electron beam melting. The irregularities caused by the manufacturing process including structural variations of the architecture are implemented in the FE models using statistical models. The predictions of FE models are compared with those of analytical models and are tested against experimental data. It is shown that, as opposed to analytical models, the predictions of FE models are in agreement with experimental observations. It is concluded that manufacturing irregularities significantly affect the mechanical properties of porous biomaterials

  16. Mechanical Properties of Nanofilled Polypropylene Composites

    Directory of Open Access Journals (Sweden)

    Cristina-Elisabeta PELIN

    2015-06-01

    Full Text Available The paper presents a study concerning mechanical performance of thermoplastic nanocomposites based on isotactic polypropylene matrix, nanofilled with montmorillonite modified with quaternary ammonium salt and carboxyl functionalized carbon nanotubes, respectively, added in the same concentration relative to the matrix. The nanofilled and single polymer materials were obtained by simple melt compounding through extrusion process followed by injection molding into specific shape specimens for mechanical testing of the samples. Mechanical properties were evaluated by tensile and 3 point bending tests. In terms of modulus of elasticity, the results showed overall positive effects concerning the effect of nanofiller addition to the thermoplastic polymer. The fracture cross section of the tested specimens was characterized by FT-IR spectroscopy and SEM microscopy.

  17. Mechanical properties of molybdenum-sealing glass-ceramics

    International Nuclear Information System (INIS)

    Swearengen, J.C.; Eagan, R.J.

    1975-07-01

    Elastic constants, thermal expansion, strength, and fracture toughness were determined for a molybdenum-sealing glass-ceramic containing approximately 31 volume percent Zn 2 SiO 4 crystals in a glass matrix. The microstructure was studied for two different crystallization treatments and moderate changes in composition. Mechanical properties of the composite were compared with the properties of the constituent phases through application of mixture theory and by fractographic observations. The reinforcing effects of the crystal phase at room temperature are evident in comparison with the properties of the residual glass but not necessarily in comparison with the parent glass. Fracture toughness of the composite depends primarily upon additive properties of the separate phases instead of by interactive effects such as microcracks. (U.S.)

  18. Structure and mechanical properties of Octopus vulgaris suckers.

    Science.gov (United States)

    Tramacere, Francesca; Kovalev, Alexander; Kleinteich, Thomas; Gorb, Stanislav N; Mazzolai, Barbara

    2014-02-06

    In this study, we investigate the morphology and mechanical features of Octopus vulgaris suckers, which may serve as a model for the creation of a new generation of attachment devices. Octopus suckers attach to a wide range of substrates in wet conditions, including rough surfaces. This amazing feature is made possible by the sucker's tissues, which are pliable to the substrate profile. Previous studies have described a peculiar internal structure that plays a fundamental role in the attachment and detachment processes of the sucker. In this work, we present a mechanical characterization of the tissues involved in the attachment process, which was performed using microindentation tests. We evaluated the elasticity modulus and viscoelastic parameters of the natural tissues (E ∼ 10 kPa) and measured the mechanical properties of some artificial materials that have previously been used in soft robotics. Such a comparison of biological prototypes and artificial material that mimics octopus-sucker tissue is crucial for the design of innovative artificial suction cups for use in wet environments. We conclude that the properties of the common elastomers that are generally used in soft robotics are quite dissimilar to the properties of biological suckers.

  19. Mechanical properties of amorphous and polycrystalline multilayer systems

    International Nuclear Information System (INIS)

    Barzen, I.; Edinger, M.; Scherer, J.; Ulrich, S.; Jung, K.; Ehrhardt, H.

    1993-01-01

    Amorphous and polycrystalline multilayer structures containing materials with metallic (Cr, Cr 3 C 2 ), ionic (Al 2 O 3 ) and covalent (SiC) bonding have been prepared by magnetron sputtering and ion plating in a dual-source apparatus. Up to 1000 layers have been deposited with a constant total thickness of 2.3 μm. Below a single-layer thickness of 10-30 nm the mechanical properties stress and hardness show strong variations. On one hand it is possible that below a certain thickness the mechanical properties of a single layer change. On the other hand electrical resistance and electron spin density measurements indicate that electronic effects may be involved. An attempt is made to explain the observed correlations by transport mechanisms of the electrons, by saturation of dangling bonds with delocalized electrons and by changes in the electronic band structure. (orig.)

  20. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

    Directory of Open Access Journals (Sweden)

    Saravana Periaswamy Sivagnanam

    2015-05-01

    Full Text Available The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri was extracted by using environmentally friendly supercritical CO2 (SC-CO2 with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v. The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.

  1. Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction.

    Science.gov (United States)

    Sivagnanam, Saravana Periaswamy; Yin, Shipeng; Choi, Jae Hyung; Park, Yong Beom; Woo, Hee Chul; Chun, Byung Soo

    2015-05-29

    The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO2 (SC-CO2) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO2 method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO2 (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO2 oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO2. The acetone-methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO2 extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.

  2. The Effect of Bedding Structure on Mechanical Property of Coal

    Directory of Open Access Journals (Sweden)

    Zetian Zhang

    2014-01-01

    Full Text Available The mechanical property of coal, influencing mining activity considerably, is significantly determined by the natural fracture distributed within coal mass. In order to study the effecting mechanism of bedding structure on mechanical property of coal, a series of uniaxial compression tests and mesoscopic tests have been conducted. The experimental results show that the distribution characteristic of calcite particles, which significantly influences the growth of cracks and the macroscopic mechanical properties of coal, is obviously affected by the bedding structure. Specifically, the uniaxial compression strength of coal sample is mainly controlled by bedding structure, and the average peak stress of specimens with axes perpendicular to the bedding planes is 20.00 MPa, which is 2.88 times the average amount of parallel ones. The test results also show a close relationship between the bedding structure and the whole deformation process under uniaxial loading.

  3. Estimation of mechanical properties of single wall carbon nanotubes ...

    Indian Academy of Sciences (India)

    Molecular mechanics; single wall carbon nanotube; mechanical proper- ... Fracture Mechanics); Rossi & Meo 2009). Furthermore, the work carried out by Natsuki & Endo. (2004), Xiao et al (2005) and Sun & Zhao (2005) in the direction of ..... Jin Y and Yuan F G 2003 Simulation of elastic properties of single walled carbon ...

  4. Structural Features of Alkaline Extracted Polysaccharide from the Seeds of Plantago asiatica L. and Its Rheological Properties

    Directory of Open Access Journals (Sweden)

    Jun-Yi Yin

    2016-09-01

    Full Text Available Polysaccharide from the seeds of Plantago asiatica L. has many bioactivities, but few papers report on the structural and rheological characteristics of the alkaline extract. The alkaline extracted polysaccharide was prepared from seeds of P. asiatica L. and named herein as alkaline extracted polysaccharide from seeds of P. asiatica L. (PLAP. Its structural and rheological properties were characterized by monosaccharide composition, methylation, GC-MS and rheometry. PLAP, as an acidic arabinoxylan, was mainly composed of 1,2,4-linked Xylp and 1,3,4-linked Xylp residues. PLAP solution showed pseudoplastic behavior, and weak gelling properties at high concentration. Sodium and especially calcium ions played a significant role in increasing the apparent viscosity and gel strength.

  5. Electron-beam irradiation effects on mechanical properties of PEEK/CF composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Seguchi, Tadao

    1989-01-01

    Carbon fibre-reinforced composite (PEEK/CF) using polyarylether-ether-ketone (PEEK) as a matrix material was prepared and electron-beam irradiation effects on the mechanical properties at low and high temperatures were studied. The flexural strength and modulus of the unirradiated PEEK/CF were almost the same as those of carbon fibre-reinforced composites with epoxide resin. The mechanical properties at room temperature were little affected by irradiation up to 180 MGy, but in the test at 77K the strength of the specimens irradiated over 100 MGy was slightly decreased. The mechanical properties of the unirradiated specimen decreased with increasing testing temperature, but the high-temperature properties were improved by irradiation, i.e. the strength measured at 413K for the specimen irradiated with 120 MGy almost reached the value for the unirradiated specimen measured at room temperature. It was apparent from the viscoelastic measurement that the improvement of mechanical properties at high temperature resulted from the high-temperature shift of the glass transition of the matrix PEEK caused by radiation-induced cross-linking. (author)

  6. Some Physical and Mechanical Properties of Daniellia Ogea Harms ...

    African Journals Online (AJOL)

    ADOWIE PERE

    density were the physical properties tested while the mechanical properties were the modulus of rupture ... 300kN capacity of the food laboratory of the department of Agriculture of the University. ..... Negro, F; Cremonini, C; Zanuttini, R (2013).

  7. Physical and mechanical properties of gamma radiation cross-linked polyethylene

    International Nuclear Information System (INIS)

    Gonzalez, Maria E.; Romero, G.; Smolko, Eduardo E.

    1999-01-01

    Granulated LDPE 2003 polyethylene was extruded and irradiated under nitrogen with 150, 200 and 300 kGy gamma rays doses to produce cross-linking. The study of the physical and mechanical properties shows that the product has a high degree of molecular cross-linking, can be heated up to 200 C for 2 hours without deformation and that the mechanical properties improve. Preliminary aging tests indicate that after heating at 60 C for 4 weeks no physical or mechanical deterioration can be observed. (author)

  8. Mechanical and corrosion properties of AA8011 sheets and foils:

    OpenAIRE

    Asanović, Vanja; Dalijić, Kemal; Radonjić, Dragan

    2006-01-01

    The mechanical and corrosion properties of a twin-roll cast Al-Fe-Si aluminum alloy with 0.74 % Fe and 0.52 % Si (AA8011) were investigated. The influence of the thermo-mehanical processing route on the mechanical behavior of AA8011 sheets was determined. Comparisons were made with AA3003 and A199.5 sheets. The restoration of the mechanical properties was used in the analysis of the recrystallization behavior of the twin-roll cast AA8011 alloy deformed under cold-working conditions and subseq...

  9. Influence of extraction conditions on antioxidant properties of passion fruit (Passiflora edulis) peel.

    Science.gov (United States)

    Wong, Yuh Shan; Sia, Chiaw Mei; Khoo, Hock Eng; Ang, Yee Kwang; Chang, Sui Kiat; Chang, Sui Kiat; Yim, Hip Seng

    2014-01-01

    As a by-product of tropical fruit juice industry, passion fruit peel is a valuable functional food. It is rich in antioxidants. To determine its potential antioxidant properties of passion fruit peel, this study aimed to evaluate the effect of extraction conditions on total phenolic content and antioxidant activity. The extraction conditions were selected from different percentages of ethanol (0-100%, v/v), extraction times (60-300 min), and extraction temperatures (25-60°C) that based on the optimal percentage of DPPH radical scavenging activity. The selected extraction condition was applied for further determination of total phenolic content (TPC) of the passion fruit peel extract using Folin-Ciocalteu reagent assay, while the antioxidant activities were evaluated using DPPH and ABTS radicals scavenging assays, ferric reducing antioxidant power (FRAP), and β-carotene bleaching (BCB) assay. The best extraction conditions were 40% ethanol, 60 min extraction time, and extraction temperature of 30°C. The chosen extraction conditions have contributed to the high TPC and antioxidant activity of passion fruit peel. The levels of antioxidant activity obtained from the passion fruit peel were also lower compared to BHA and α-tocopherol. Positive correlations were observed between TPC and antioxidant activities as assessed by DPPH, ABTS, FRAP, and BCB assays. As a waste of passion fruit consumption or by-product of fruit juice industry, its peel could be considered as a potential source of natural antioxidant for possible functional food and industrial applications.

  10. Influence of Compatibilizer and Processing Conditions on Morphology, Mechanical Properties, and Deformation Mechanism of PP/Clay Nano composite

    International Nuclear Information System (INIS)

    Akbari, B.; Bagheri, R.

    2012-01-01

    Polypropylene/montmorillonite nano composite was prepared by melt intercalation method using a twin-screw extruder with starve feeding system in this paper. The effects of compatibilizer, extruder rotor speed and feeding rate on properties of nano composite were investigated. Structure, tensile, and impact properties and deformation mechanism of the compounds were studied. For investigation of structure and deformation mechanisms, X-ray diffraction (XRD) and transmission optical microscopy (TOM) techniques were utilized, respectively. The results illustrate that introduction of the compatibilizer and also variation of the processing conditions affect structure and mechanical properties of nano composite.

  11. Mechanical properties of welded joints of duplex steels

    International Nuclear Information System (INIS)

    Kawiak, M.; Nowacki, J.

    2003-01-01

    The paper presents the study results of mechanical properties of duplex steels UNS S31803 welded joints as well as duplex and NV A36 steels welded joints. They have ben welded by FCAW method in CO 2 using FCW 2205-H flux-cored wire. The joints have been subjected: tensile tests, impact tests, bending tests, hardness tests and metallographic investigations. The influence of welding parameters and mechanical properties of the joints was appreciated. The welding method assured high tensile strength of the joints (approximately 770 MPa) and high impact strength of the welds (approximately 770 J). All samples were broken outside of welds. (author)

  12. Improvement of the mechanical properties of reinforced aluminum foam samples

    Science.gov (United States)

    Formisano, A.; Barone, A.; Carrino, L.; De Fazio, D.; Langella, A.; Viscusi, A.; Durante, M.

    2018-05-01

    Closed-cell aluminum foam has attracted increasing attention due to its very interesting properties, thanks to which it is expected to be used as both structural and functional material. A research challenge is the improvement of the mechanical properties of foam-based structures adopting a reinforced approach that does not compromise their lightness. Consequently, the aim of this research is the fabrication of enhanced aluminum foam samples without significantly increasing their original weight. In this regard, cylindrical samples with a core of closed-cell aluminum foam and a skin of fabrics and grids of different materials were fabricated in a one step process and were mechanically characterized, in order to investigate their behaviour and to compare their mechanical properties to the ones of the traditional foam.

  13. Thermal and Mechanical Properties of Poly(butylene succinate Films Reinforced with Silica

    Directory of Open Access Journals (Sweden)

    Sangviroon Nanthaporn

    2015-01-01

    Full Text Available In recent year, bioplastics have become more popular resulting from the growing concerns on environmental issues and the rising fossil fuel price. However, their applications were limited by its mechanical and thermal properties. The aim of this research is thus to improve mechanical and thermal properties of PBS bioplastic films by reinforcing with silica. Due to the poor interfacial interaction between the PBS matrix and silica, glycidyl methacrylate grafted poly(butylene succinate (PBS-g-GMA was used as a compatibilizer in order to improve the interaction between bioplastic films and filler. PBS-g-GMA was prepared in a twin-screw extruder and analyzed by the FTIR spectrometer. PBS and silica were then mixed in a twin-screw extruder and processed into films by a chill-roll cast extruder. The effects of silica loading on thermal and mechanical properties of the prepared bioplastic films were investigated. It was found that the mechanical properties of PBS/silica composite films were improved when 1%wt of silica was added. However, the mechanical properties decreased with increasing silica loading due to the agglomeration of silica particles. The results also show that the silica/PBS films with PBS-g-GMA possessed improved mechanical properties over the films without the compatibilizer.

  14. Co-processing Plant Extracts for Improvement of Their Pharmacotechnic Properties

    Directory of Open Access Journals (Sweden)

    P. C. Gustmann

    2012-11-01

    Full Text Available ABSTRACT: The herbal Espinheira Santa (Maytenus ilicifolia can ingested in capsules for treatment of injuries from digestive tract, such as gastritis. However, the large amount of drug administered dose medication adherence difficult, so this study sought an alternative by formulating effervescent granules facilitating drug intake. The obtained granules made by wet and effervescent mixture of citric acid, sodium carbonate and sodium bicarbonate at different concentrations, totaling eight formulations, in addition to lactose as diluent and disintegrant in the composition. The granules were produced in sizes from 1 and 2mm. Rheological tests were compared against the dry extract, analyzed the average particle sizes of beads, mapped its surface by scanning electron microscopy and evaluated their behavior effervescent. The flow properties of the granules showed better values than the dry extract. The co-processed formulations showed average particle sizes distributed closed, where 1mm time effervescence had smaller, respecting all formulations, pharmacopeial limits of maximum 5 minutes. The preparation of effervescent granules Espinheira Santa proved to be a good alternativel, once that have easy preparation, low cost, excellent flow and rapid disintegration.Keywords: Espinheira Santa, effervescent granules, dry extract.

  15. Experimental measurement and modeling analysis on mechanical properties of incudostapedial joint.

    Science.gov (United States)

    Zhang, Xiangming; Gan, Rong Z

    2011-10-01

    The incudostapedial (IS) joint between the incus and stapes is a synovial joint consisting of joint capsule, cartilage, and synovial fluid. The mechanical properties of the IS joint directly affect the middle ear transfer function for sound transmission. However, due to the complexity and small size of the joint, the mechanical properties of the IS joint have not been reported in the literature. In this paper, we report our current study on mechanical properties of human IS joint using both experimental measurement and finite element (FE) modeling analysis. Eight IS joint samples with the incus and stapes attached were harvested from human cadaver temporal bones. Tension, compression, stress relaxation and failure tests were performed on those samples in a micro-material testing system. An analytical approach with the hyperelastic Ogden model and a 3D FE model of the IS joint including the cartilage, joint capsule, and synovial fluid were employed to derive mechanical parameters of the IS joint. The comparison of measurements and modeling results reveals the relationship between the mechanical properties and structure of the IS joint.

  16. Intrinsic and extrinsic mechanical properties related to the differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Lee, Jin-Ho; Park, Hun-Kuk; Kim, Kyung Sook

    2016-05-06

    Diverse intrinsic and extrinsic mechanical factors have a strong influence on the regulation of stem cell fate. In this work, we examined recent literature on the effects of mechanical environments on stem cells, especially on differentiation of mesenchymal stem cells (MSCs). We provide a brief review of intrinsic mechanical properties of single MSC and examined the correlation between the intrinsic mechanical property of MSC and the differentiation ability. The effects of extrinsic mechanical factors relevant to the differentiation of MSCs were considered separately. The effect of nanostructure and elasticity of the matrix on the differentiation of MSCs were summarized. Finally, we consider how the extrinsic mechanical properties transfer to MSCs and then how the effects on the intrinsic mechanical properties affect stem cell differentiation. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Synthesis, microstructure and mechanical properties of ceria ...

    Indian Academy of Sciences (India)

    Unknown

    ceria stabilized zirconia powders with improved mechanical properties. Ce–ZrO2 with 20 wt% ... structural ceramic materials (Garvie et al 1975; Evans and. Cannon 1986) ... thermal expansion matching with that of iron alloys. (Tsukuma and ...

  18. Mechanical properties of cork under contact stresses

    International Nuclear Information System (INIS)

    Parralejo, A. D.; Guiberteau, F.; Fortes, M. A.; Rosa, M. E.

    2001-01-01

    In this work our interest is focussed on the mechanical behaviour of natural cork under contact stresses. Many of the applications of this curious material are related with its mechanical response under such a stress field, however this topic has not been still sufficiently considered in the scientific literature. For this purpose, we proposed the use of Hertzian indentation tests. By using this mythology we have investigated the cork structure influence on the corresponding mechanical properties. Our results reveal a clear mechanical anisotropy effect. Moreover, the elastic modulus corresponding to specific directions have been estimated. Several are the main advantages of this specific test mythology versus traditional uniaxial compression tests, specially simplicity and local character. (Author) 9 refs

  19. Mechanical properties and failure behaviour of graphene/silicene/graphene heterostructures

    International Nuclear Information System (INIS)

    Chung, Jing-Yang; Sorkin, Viacheslav; Pei, Qing-Xiang; Zhang, Yong-Wei; Chiu, Cheng-Hsin

    2017-01-01

    Van der Waals heterostructures based on graphene and other 2D materials have attracted great attention recently. In this study, the mechanical properties and failure behaviour of a graphene/silicene/graphene heterostructure are investigated using molecular dynamics simulations. We find that by sandwiching silicene in-between two graphene layers, both ultimate tensile strength and Young’s modulus of the heterostructure increase approximately by a factor of 10 compared with those of stand-alone silicene. By examining the fracture process of the heterostructure, we find that graphene and silicene exhibit quite different fracture behaviour. While graphene undergoes cleavage through its zigzag edge only, silicene can cleave through both its zigzag and armchair edges. In addition, we study the effects of temperature and strain rate on the mechanical properties of the heterostructure and find that an increase in temperature results in a decrease in its mechanical strength and stiffness, while an increase in strain rate leads to an increase in its mechanical strength without significant changes in its stiffness. We further explore the failure mechanism and show that the temperature and strain-rate dependent fracture stress can be accurately described by the kinetic theory of fracture. Our findings provide a deep insight into the mechanical properties and failure mechanism of graphene/silicene heterostructures. (paper)

  20. Lamiaceae extracts as a source of phytochemicals with promissory antioxidant properties

    OpenAIRE

    Martins, Natália; Heleno, Sandrina A.; Barros, Lillian; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.

    2015-01-01

    Plant extracts have been used over years due to their marked healing properties. Primitive societies used them not only as botanical preparations for therapeutic uses, but also as prophylaxis and for psychological effects. Despite the recognized millenary health evidences, numerous phytochemicals responsible for those benefits remain unknown. Among the heterogeneous group of secondary metabolites, phenolic compounds have been pointed out as relevant bioactive phytochemicals [1-3]....

  1. Comparison of mechanical properties for several electrical spring contact alloys

    International Nuclear Information System (INIS)

    Nordstrom, T.V.

    1976-06-01

    Work was conducted to determine whether beryllium-nickel alloy 440 had mechanical properties which made it suitable as a substitute for the presently used precious metal contact alloys Paliney 7 and Neyoro G, in certain electrical contact applications. Possible areas of applicability for the alloy were where extremely low contact resistance was not necessary or in components encountering elevated temperatures above those presently seen in weapons applications. Evaluation of the alloy involved three major experimental areas: 1) measurement of the room temperature microplastic (epsilon approximately 10 -6 ) and macroplastic (epsilon approximately 10 -3 ) behavior of alloy 440 in various age hardening conditions, 2) determination of applied stress effects on stress relaxation or contact force loss and 3) measurement of elevated temperature mechanical properties and stress relaxation behavior. Similar measurements were also made on Neyoro G and Paliney 7 for comparison. The primary results of the study show that beryllium-nickel alloy 440 is from a mechanical properties standpoint, equal or superior to the presently used Paliney 7 and Neyoro G for normal Sandia requirements. For elevated temperature applications, alloy 440 has clearly superior mechanical properties

  2. Sterilizing elastomeric chains without losing mechanical properties. Is it possible?

    Directory of Open Access Journals (Sweden)

    Matheus Melo Pithon

    2015-06-01

    Full Text Available OBJECTIVE: To investigate the effects of different sterilization/disinfection methods on the mechanical properties of orthodontic elastomeric chains. METHODS: Segments of elastomeric chains with 5 links each were sent for sterilization by cobalt 60 (Co60 (20 KGy gamma ray technology. After the procedure, the elastomeric chains were contaminated with clinical samples of Streptococcus mutans. Subsequently, the elastomeric chains were submitted to sterilization/disinfection tests carried out by means of different methods, forming six study groups, as follows: Group 1 (control - without contamination, Group 2 (70°GL alcohol, Group 3 (autoclave, Group 4 (ultraviolet, Group 5 (peracetic acid and Group 6 (glutaraldehyde. After sterilization/disinfection, the effectiveness of these methods, by Colony forming units per mL (CFU/mL, and the mechanical properties of the material were assessed. Student's t-test was used to assess the number of CFUs while ANOVA and Tukey's test were used to assess elastic strength. RESULTS: Ultraviolet treatment was not completely effective for sterilization. No loss of mechanical properties occurred with the use of the different sterilization methods (p > 0.05. CONCLUSION: Biological control of elastomeric chains does not affect their mechanical properties.

  3. Influence of soil and hydrocarbon properties on the solvent extraction of high-concentration weathered petroleum from contaminated soils.

    Science.gov (United States)

    Sui, Hong; Hua, Zhengtao; Li, Xingang; Li, Hong; Wu, Guozhong

    2014-05-01

    Petroleum ether was used to extract petroleum hydrocarbons from soils collected from six oil fields with different history of exploratory and contamination. It was capable of fast removing 76-94 % of the total petroleum hydrocarbons including 25 alkanes (C11-C35) and 16 US EPA priority polycyclic aromatic hydrocarbons from soils at room temperature. The partial least squares analysis indicated that the solvent extraction efficiencies were positively correlated with soil organic matter, cation exchange capacity, moisture, pH, and sand content of soils, while negative effects were observed in the properties reflecting the molecular size (e.g., molecular weight and number of carbon atoms) and hydrophobicity (e.g., water solubility, octanol-water partition coefficient, soil organic carbon partition coefficient) of hydrocarbons. The high concentration of weathered crude oil at the order of 10(5) mg kg(-1) in this study was demonstrated adverse for solvent extraction by providing an obvious nonaqueous phase liquid phase for hydrocarbon sinking and increasing the sequestration of soluble hydrocarbons in the insoluble oil fractions during weathering. A full picture of the mass distribution and transport mechanism of petroleum contaminants in soils will ultimately require a variety of studies to gain insights into the dynamic interactions between environmental indicator hydrocarbons and their host oil matrix.

  4. Mechanical properties of experimental composites with different calcium phosphates fillers.

    Science.gov (United States)

    Okulus, Zuzanna; Voelkel, Adam

    2017-09-01

    Calcium phosphates (CaPs)-containing composites have already shown good properties from the point of view of dental restorative materials. The purpose of this study was to examine the crucial mechanical properties of twelve hydroxyapatite- or tricalcium phosphate-filled composites. The raw and surface-treated forms of both CaP fillers were applied. As a reference materials two experimental glass-containing composites and one commercial dental restorative composite were applied. Nano-hardness, elastic modulus, compressive, flexural and diametral tensile strength of all studied materials were determined. Application of statistical methods (one-way analysis of variance and cluster agglomerative analysis) allowed for assessing the similarities between examined materials according to the values of studied parameters. The obtained results show that in almost all cases the mechanical properties of experimental CaPs-composites are comparable or even better than mechanical properties of examined reference materials. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Basic requirements of mechanical properties for nuclear pressure vessel materials in ASME-BPV code

    International Nuclear Information System (INIS)

    Ning Dong; Yao Weida

    2011-01-01

    The four basic aspects of strengths, ductility, toughness and fatigue strengths can be summarized for overall mechanical properties requirements of materials for nuclear pressure-retaining vessels in ASME-BPV code. These mechanical property indexes involve in the factors of melting, manufacture, delivery conditions, check or recheck for mechanical properties and chemical compositions, etc. and relate to degradation and damage accumulation during the use of materials. This paper specifically accounts for the basic requirements and theoretic basis of mechanical properties for nuclear pressure vessel materials in ASME-BPV code and states the internal mutual relationships among the four aspects of mechanical properties. This paper focuses on putting forward at several problems on mechanical properties of materials that shall be concerned about during design and manufacture for nuclear pressure vessels according to ASME-BPV code. (author)

  6. Thermal Properties of Wood-Plastic Composites Prepared from Hemicellulose-extracted Wood Flour

    Directory of Open Access Journals (Sweden)

    A.A. Enayati

    2013-01-01

    Full Text Available Hemicellulose of Southern Yellow Pine wood spices was extracted by pressurized hot water at three different temperatures: 140°C, 155°C and 170°C. Compounding with PP (polypropylene was performed by extrusion after preparing wood flour and sieving to determine its mesh size. The ratio of wood to polymer was 50:50 based on oven-dry weight of wood flour. All extraction treatments and control samples were compounded under two sets of conditions, without and with 2% MAPP as coupling agent. Injection molding was used to make tensile test samples (dogbone from the pellets made by extrusion. Thermal properties of wood-plastic composites were studied by TGA and DSC while the thermal stability of pretreated wood flours, PP and MAPP were studied by TGA as well. The greater weight loss of wood materials was an indication that higher treatment temperature increases the extractability of hemicellulose. The removal of hemicellulose by extraction improves thermal stability of wood flour, especially for extraction at 170°C. Wood-plastic composites made from extracted fibers at 170°C showed the highest thermal stability. Coupling agent did not have a significant effect on thermal stability but it improved the degree of crystallinity of the composites.Surface roughness of wood fiber increased after treatment. Extraction of hemicellulose increased the degree of crystallinity but it was not significant except for samples from treated wood flour at 170°C and with MAPP.

  7. Impact of chemical treatments on the mechanical and water absorption properties of coconut fibre (Cocos nucifera reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    Isiaka O. OLADELE

    2016-07-01

    Full Text Available In this work, chemically treated coconut fibres were used to reinforce Homopolymer Polypropylene in order to ascertain the effect of the treatments on the mechanical and water absorption properties of the composites produced. Coconut fibre was first extracted from its husk by soaking it in water and was dried before it was cut into 10 mm lengths. It was then chemically treated in alkali solution of sodium hydroxide (NaOH and potassium hydroxide (KOH in a shaker water bath. The treated coconut fibres were used as reinforcements in polypropylene matrix to produce composites of varied fibre weight contents; 2, 4, 6, 8 and 10 wt.%. Tensile and flexural properties were investigated using universal testing machine while water absorption test was carried out on the samples for 7 days. It was observed from the results that, NaOH treated samples gave the best tensile properties while KOH treated samples gave the best flexural and water repellent properties.

  8. Mechanical properties of papercrete

    Directory of Open Access Journals (Sweden)

    Zaki Harith

    2018-01-01

    Full Text Available This paper studies the uses, of waste paper as an additional material in concrete mixes. Papercrete is a term as the name seems, to imply a mixture of paper and concrete. It is a new, composite material using waste paper, as a partial addition of Portland cement, and is a sustainable, building material due to, reduced amount of waste paper being put to use. It gains, latent strength due to presence of hydrogen bonds in microstructure of paper. Papercrete has been, reported to be a low cost alternative, building construction, material and has, good sound absorption, and thermal insulation; to be a lightweight and fire-resistant material. The percent of waste paper used (after treating namely (5%, 10%, 15% and 20% by weight of cement to explore the mechanical properties of the mixes (compressive strength, splitting tensile strength, flexural strength, density, as compared with references mixes, it was found that fresh properties affected significantly by increasing the waste paper content. The compressive strength, splitting tensile strength, flexural strength and density got decreased with increase in the percentage of paper.

  9. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform Fabrication

    Science.gov (United States)

    Domack, Marcia S.; Taminger, Karen M. B.; Begley, Matthew

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  10. Mechanical Properties of Isotactic Polypropylene Modified with Thermoplastic Potato Starch

    Science.gov (United States)

    Knitter, M.; Dobrzyńska-Mizera, M.

    2015-05-01

    In this paper selected mechanical properties of isotactic polypropylene (iPP) modified with potato starch have been presented. Thermoplastic starch (TPS) used as a modifier in the study was produced from potato starch modified with glycerol. Isotactic polypropylene/thermoplastic potato starch composites (iPP/TPS) that contained 10, 30, 50 wt.% of modified starch were examined using dynamic mechanical-thermal analysis, static tensile, Brinell hardness, and Charpy impact test. The studies indicated a distinct influence of a filler content on the mechanical properties of composites in comparison with non-modified polypropylene.

  11. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    OpenAIRE

    Hadryś D.

    2016-01-01

    New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF) in weld metal deposit...

  12. The factors influencing microstructure and mechanical properties of ADI

    Directory of Open Access Journals (Sweden)

    A. Vaško

    2009-01-01

    Full Text Available The paper deals with the influence of different conditions of isothermal heat treatment on microstructure and mechanical properties of austempered ductile iron (ADI. Different temperature of isothermal transformation of austenite and different holding time at this temperature were used for heat treatment of specimens. The microstructure of specimens after casting and after heat treatment was evaluated by STN EN ISO 945 and by image analysis (using Lucia software. Mechanical properties were evaluated by the tensile test, the Rockwell hardness test and fatigue tests.

  13. Effect of sample thickness on the extracted near-infrared bulk optical properties of Bacillus subtilis in liquid culture.

    Science.gov (United States)

    Dzhongova, Elitsa; Harwood, Colin R; Thennadil, Suresh N

    2011-11-01

    In order to determine the bulk optical properties of a Bacillus subtilis culture during growth phase we investigated the effect of sample thickness on measurements taken with different measurement configurations, namely total diffuse reflectance and total diffuse transmittance. The bulk optical properties were extracted by inverting the measurements using the radiative transfer theory. While the relationship between reflectance and biomass changes with sample thickness and the intensity (absorbance) levels vary significantly for both reflectance and transmittance measurements, the extracted optical properties show consistent behavior in terms of both the relationship with biomass and magnitude. This observation indicates the potential of bulk optical properties for building models that could be more easily transferable compared to those built using raw measurements.

  14. A comparative study of the character and complexation properties of in-situ and extracted humic and fulvic substances

    International Nuclear Information System (INIS)

    Warwick, P.; Hall, A.; Patterson, M.

    1992-12-01

    The character and complexation properties of humic and fulvic acids, derived from a moorland water, have been studied, both under ''in-situ'' conditions and also after extraction. The characterisation studies involved determinations of UV-visible properties, fluorescence properties. size ranges, molecular weights and proton capacities. Complexation studies were conducted using High Performance Size Exclusion Chromatography, Fluorescence Reduction and the Schubert Ion Exchange Method. A strong and weak site ligand model was used to interpret the data. The effects of pH, ionic strength, side reactions, ligand type, purity and nature of the cation were considered. No major differences in the character or complexation properties of the in-situ and extracted materials were found. (Author)

  15. Structure-property effects on mechanical, friction and wear properties of electron modified PTFE filled EPDM composite

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Tribological properties of Ethylene-Propylene-Diene-rubber (EPDM containing electron modified Polytetrafluoroethylene (PTFE have been investiagted with the help of pin on disk tribometer without lubrication for a testing time of 2 hrs in atmospheric conditions at a sliding speed and applied normal load of 0.05 m•s–1 and FN = 1 N, respectively. Radiation-induced chemical changes in electron modified PTFE powders were analyzed using Electron Spin Resonance (ESR and Fourier Transform Infrared (FTIR specroscopy to characterize the effects of compatibility and chemical coupling of modified PTFE powders with EPDM on mechanical, friction and wear properties. The composites showed different friction and wear behaviour due to unique morphology, dispersion behaviour and radiation functionalization of PTFE powders. In general, EPDM reinforced with electron modified PTFE powder demonstrated improvement both in mechanical and tribological properties. However, the enhanced compatibility of PTFE powder resulting from the specific chemical coupling of PTFE powder with EPDM has been found crucial for mechanical, friction and wear properties.

  16. Fullerene–epoxy nanocomposites-enhanced mechanical properties at low nanofiller loading

    International Nuclear Information System (INIS)

    Rafiee, Mohammad A.; Yavari, Fazel; Rafiee, Javad; Koratkar, Nikhil

    2011-01-01

    In this study, we characterized the mechanical properties of fullerence (C 60 ) epoxy nanocomposites at various weight fractions of fullerene additives in the epoxy matrix. The mechanical properties measured were the Young’s modulus, ultimate tensile strength, fracture toughness, fracture energy, and the material’s resistance to fatigue crack propagation. All of the above properties of the epoxy polymer were significantly enhanced by the fullerene additives at relatively low nanofiller loading fractions (∼0.1 to 1% of the epoxy matrix weight). By contrast, other forms of nanoparticle fillers such as silica, alumina, and titania nanoparticles require up to an order of magnitude higher weight fraction to achieve comparable enhancement in properties.

  17. INVESTIGATION OF HYGROSCOPIC PROPERTIES OF POWDER OF SEMIFINISHED KVASS WORT CONCENTRATE, MALT EXTRACT OF BARLEY AND CHICORY EXTRACT

    Directory of Open Access Journals (Sweden)

    G. O. Magomedov

    2015-01-01

    Full Text Available Food industry of Russia urgently needs both updating of the manufacturing units of equipment and the creation of new high-tech and energy-saving technologies. Nowadays powdered food products and semifinished foods gained wide popularity in the market of foods and in manufacturing. Due to the caking and low wettability of fine powdered semi-finished products, there is an urgent need for modifying their properties by instanting. This article is devoted to the study of hygroscopic properties of powdered products and semifinished products: chicory extract, barley malt extract, kvass wort concentrate obtained by spray drying with an average dispersed composition of 10-20 microns, to find optimal conditions for packaging, storage and theoretical justification of the instanting process conditions. The article provides a diagram of experimental device for the study of hygroscopic properties of food powdered semi-finished products by accelerated method with the creation of the fluidized bed and the required temperature and humidity characteristics of fluidizing agent. The principles of operation of the device and methods of the experiment carrying out are given. The results are given in the form of sorption isotherms, by which monomolecular poly-molecular and capillary forms of binding of moisture with the test products and semi-finished products are determined. Theoretical nomogram to determine the binding energy of the moisture with the semi-finished products is given. Mathematical dependences of equilibrium humidities in the studied powdered products and semi-finished products on the air relative humidity in the range of 15 to 85 % at a temperature 22 ˚C were obtained. Optimal humidity properties of the resulting products for their production and subsequent storage and for the instanting processes were determined.

  18. Improvement of mechanical properties of zirconia-toughened alumina by sinter forging

    NARCIS (Netherlands)

    He, Y.; Winnubst, Aloysius J.A.; Verweij, H.; Burggraaf, Anthonie; Burggraaf, A.J.

    1994-01-01

    ZTA powder with a composition of 85 wt% alumina/15 wt% zirconia was prepared by a gel precipitation method. Sinter forging was performed with this powder to enhance the mechanical properties of ZTA materials. The influence of processing flaws on mechanical properties of sinter forged materials and

  19. Properties and mechanical behaviour of fuel cans of fast neutron reactors

    International Nuclear Information System (INIS)

    Cauvin, R.; Boutard, J.L.

    1983-06-01

    Mechanical properties of Stainless steel-316 irradiated up to 100 dpa in fast neutron reactors are examined. Microscopic phenomena involved are reviewed: precipitation, segregation, dislocations, vacancies. Influence on mechanical behaviour of materials are examined: tensile properties, creep, ductility. Consequences on reactor dimensioning are given in conclusion [fr

  20. Microstructure, mechanical properties, bio-corrosion properties and cytotoxicity of as-extruded Mg-Sr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chaoyong [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Pan, Fusheng, E-mail: fspan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Zhang, Lei; Pan, Hucheng; Song, Kai; Tang, Aitao [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2017-01-01

    In this study, as-extruded Mg-Sr alloys were studied for orthopedic application, and the microstructure, mechanical properties, bio-corrosion properties and cytotoxicity of as-extruded Mg-Sr alloys were investigated by optical microscopy, scanning electron microscopy with an energy dispersive X-ray spectroscopy, X-ray diffraction, tensile and compressive tests, immersion test, electrochemical test and cytotoxicity test. The results showed that as-extruded Mg-Sr alloys were composed of α-Mg and Mg{sub 17}Sr{sub 2} phases, and the content of Mg{sub 17}Sr{sub 2} phases increased with increasing Sr content. As-extruded Mg-Sr alloy with 0.5 wt.% Sr was equiaxed grains, while the one with a higher Sr content was long elongated grains and the grain size of the long elongated grains decreased with increasing Sr content. Tensile and compressive tests showed an increase of both tensile and compressive strength and a decrease of elongation with increasing Sr content. Immersion and electrochemical tests showed that as-extruded Mg-0.5Sr alloy exhibited the best anti-corrosion property, and the anti-corrosion property of as-extruded Mg-Sr alloys deteriorated with increasing Sr content, which was greatly associated with galvanic couple effect. The cytotoxicity test revealed that as-extruded Mg-0.5Sr alloy did not induce toxicity to cells. These results indicated that as-extruded Mg-0.5Sr alloy with suitable mechanical properties, corrosion resistance and good cytocompatibility was potential as a biodegradable implant for orthopedic application. - Highlights: • Biodegradable as-extruded Mg-Sr alloys were fabricated. • Microstructure of alloys changed with increasing Sr content. • Mechanical properties of alloys could be controlled by adjusting the Sr content. • Corrosion properties of alloys decreased with increasing Sr content. • As-extruded Mg-0.5Sr alloy was potential for orthopedic application.

  1. Tensile mechanical properties of U3Si2-Al fuel plate

    International Nuclear Information System (INIS)

    Xu Yong; Hu Huawei; Zhuang Hongquan; Wang Xishu

    2003-01-01

    The fuel plate made of fuel meat, with the U 3 Si 2 -Al dispersion fuel center, and 6061 Al alloy cladding, is a new kind of fuel used in research reactors. The mechanical property data of the fuel meat is the basic data in the design of fuel group, but the mechanical property of this fuel meat has not been studied all over the world till now. In this paper, the mechanical properties of U 3 Si 2 -Al fuel meats of different sizes used in research reactors are investigated and analyzed, and at the same time the carrying capacity of tensile in different directions are also compared. In order to get more knowledge about the mechanical properties of the fuel meat, the tensile experiment has been carried out repeatedly. Considering the lower ratio of elongation and the brittleness, the microscope has been used to examine the zone of fracture after tensile test. (authors)

  2. Size Effect of Defects on the Mechanical Properties of Graphene

    Science.gov (United States)

    Park, Youngho; Hyun, Sangil

    2018-03-01

    Graphene, a two-dimensional material, has been studied and utilized for its excellent material properties. In reality, achieving a pure single-crystalline structure in graphene is difficult, so usually graphene may have various types of defects in it. Vacancies, Stone-Wales defects, and grain boundaries can drastically change the material properties of graphene. Graphene with vacancy defects has been of interest because it is a two-dimensional analogy of three-dimensional porous materials. It has efficient material properties, and can function as a part of modern devices. The mechanical properties have been studied by using molecular dynamics for either a single vacancy defect with various sizes or multiple vacancy defects with same defect ratios. However, it is not clear which one has more influence on the mechanical properties between the size of the defects and the defect ratio. Therefore, we investigated the hole-size effect on the mechanical properties of single-crystalline graphene at various defect ratios. A void defect with large size can have a rather high tensile modulus with a low fracture strain compared to a void defect with small size. We numerically found that the tensile properties of scattered single vacancies is similar to that of amorphous graphene. We suspect that this is due to the local orbital change of the carbon atoms near the boundary of the void defects, so-called the interfacial phase.

  3. Effects of gamma rays on the physical and mechanical properties of hide

    International Nuclear Information System (INIS)

    Sutrisno Puspodikoro.

    1976-01-01

    The effect of gamma rays on the physical and mechanical properties of hide has been studied, using Gammacell 220 as an irradiator. The determination of the physical and mechanical properties of the irradiated hide was carried out by Balai Penelitian Kulit (Leather Research Institute) at Yogyakarta. Experiments show that up to a certain dose of irradiation, favourable effects can be obtained, while higher doses impair the physical and mechanical properties of the leather raw materials. (author)

  4. Mechanical properties of polyelectrolyte multilayer self-assembled films

    International Nuclear Information System (INIS)

    Dai Xinhua; Zhang Yongjun; Guan Ying; Yang Shuguang; Xu Jian

    2005-01-01

    The mechanical properties of electrostatic self-assembled multilayer films from polyacrylic acid (PAA) and C 60 -ethylenediamine adduct (C 60 -EDA) or poly(allylamine hydrochloride) (PAH) were evaluated by atomic force microscopy (AFM) wear experiments. Because of the higher molecular weight of PAH, the wear resistance of the (PAH/PAA) 10 film is higher than that of the (PAH/PAA) 2 (C 60 -EDA/PAA) 8 film; that is, the former is mechanically more stable than the latter. The mechanical stability of both films can be improved significantly by heat treatment, which changes the nature of the linkage from ionic to covalent. The AFM measurement also reveals that the (PAH/PAA) 2 (C 60 -EDA/PAA) 8 film is softer than the (PAH/PAA) 10 film. The friction properties of the heated films were measured. These films can be developed as potential lubrication coatings for microelectromechanical systems

  5. Prediction of mechanical properties of Al alloys with change of cooling rate

    Directory of Open Access Journals (Sweden)

    Quan-Zhi Dong

    2012-11-01

    Full Text Available The solidification process significantly affects the mechanical properties and there are lots of factors that affect the solidification process. Much progress has been made in the research on the effect of solidification on mechanical properties. Among them, the PF (Phase Field model and CA (Cellular Automata model are widely used as simulation methods which can predict nucleation and its growth, and the size and morphology of the grains during solidification. Although they can give accurate calculation results, it needs too much computational memory and calculation time. So it is difficult to apply the simulation to the real production process. In this study, a more practical simulation approach which can predict the mechanical properties of real aluminum alloys is proposed, by identifying through experiment the relationship between cooling rate and SDAS (Secondary Dendrite Arm Spacing and mechanical properties. The experimentally measured values and the values predicted by simulation have relatively small differences and the mechanical properties of a variety of Al alloys are expected to be predicted before casting through use of the simulation.

  6. Effect of stacking sequence on mechanical properties neem wood veneer plastic composites

    Science.gov (United States)

    Nagamadhu, M.; Kumar, G. C. Mohan; Jeyaraj, P.

    2018-04-01

    This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images.

  7. Influence of Temperature on Mechanical Properties of Jute/Biopolymer Composites

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Laursen, Louise Løcke; Løgstrup Andersen, Tom

    2013-01-01

    Biopolymers and natural fibers are receiving wide attention for the potential to have good performance composites with low environmental impact. A current limitation of most biopolymers is however their change in mechanical properties at elevated temperatures. This study investigates the mechanical...... of the fibers. Altogether, the results demonstrate that the thermal sensitivity parameters typically provided for polymers, e.g., the glass transition temperature and the heat deflection temperature, cannot be used as sole parameters for determining the gradual change in mechanical properties of polymers...... properties of two biomass-based polymers, polylactic acid (PLA) and cellulose acetate (CA), as a function of ambient temperature in the range from 5 to 80C. Tests were done for neat polymers and for jute fiber/biopolymer composites. Micromechanical models were applied to back-calculate the reinforcement...

  8. Mechanical and tribological properties of ion beam-processed surfaces

    International Nuclear Information System (INIS)

    Kodali, P.

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness

  9. Cartilage-like mechanical properties of poly (ethylene glycol)-diacrylate hydrogels.

    Science.gov (United States)

    Nguyen, Quynhhoa T; Hwang, Yongsung; Chen, Albert C; Varghese, Shyni; Sah, Robert L

    2012-10-01

    Hydrogels prepared from poly-(ethylene glycol) (PEG) have been used in a variety of studies of cartilage tissue engineering. Such hydrogels may also be useful as a tunable mechanical material for cartilage repair. Previous studies have characterized the chemical and mechanical properties of PEG-based hydrogels, as modulated by precursor molecular weight and concentration. Cartilage mechanical properties vary substantially, with maturation, with depth from the articular surface, in health and disease, and in compression and tension. We hypothesized that PEG hydrogels could mimic a broad range of the compressive and tensile mechanical properties of articular cartilage. The objective of this study was to characterize the mechanical properties of PEG hydrogels over a broad range and with reference to articular cartilage. In particular, we assessed the effects of PEG precursor molecular weight (508 Da, 3.4 kDa, 6 kDa, and 10 kDa) and concentration (10-40%) on swelling property, equilibrium confined compressive modulus (H(A0)), compressive dynamic stiffness, and hydraulic permeability (k(p0)) of PEG hydrogels in static/dynamic confined compression tests, and equilibrium tensile modulus (E(ten)) in tension tests. As molecular weight of PEG decreased and concentration increased, hydrogels exhibited a decrease in swelling ratio (31.5-2.2), an increase in H(A0) (0.01-2.46 MPa) and E(ten) (0.02-3.5 MPa), an increase in dynamic compressive stiffness (0.055-42.9 MPa), and a decrease in k(p0) (1.2 × 10(-15) to 8.5 × 10(-15) m(2)/(Pa s)). The frequency-dependence of dynamic compressive stiffness amplitude and phase, as well as the strain-dependence of permeability, were typical of the time- and strain-dependent mechanical behavior of articular cartilage. H(A0) and E(ten) were positively correlated with the final PEG concentration, accounting for swelling. These results indicate that PEG hydrogels can be prepared to mimic many of the static and dynamic mechanical

  10. Material, compressional and mechanical properties of Borassus ...

    African Journals Online (AJOL)

    The compressional and mechanical properties of tablet formulations incorporating native and modified Borassus aethiopum starches as binder were evaluated. The native Borassus aethiopum starch (BAS) was modified to yield fully gelatinised starch (FGBAS) and microcrystalline starch (MBAS). The compressional ...

  11. Mechanical and irradiation properties of zirconium alloys irradiated in HANARO

    International Nuclear Information System (INIS)

    Kwon, Oh Hyun; Eom, Kyong Bo; Kim, Jae Ik; Suh, Jung Min; Jeon, Kyeong Lak

    2011-01-01

    These experimental studies are carried out to build a database for analyzing fuel performance in nuclear power plants. In particular, this study focuses on the mechanical and irradiation properties of three kinds of zirconium alloy (Alloy A, Alloy B and Alloy C) irradiated in the HANARO (High-flux Advanced Neutron Application Reactor), one of the leading multipurpose research reactors in the world. Yield strength and ultimate tensile strength were measured to determine the mechanical properties before and after irradiation, while irradiation growth was measured for the irradiation properties. The samples for irradiation testing are classified by texture. For the irradiation condition, all samples were wrapped into the capsule (07M-13N) and irradiated in the HANARO for about 100 days (E > 1.0 MeV, 1.1 10 21 n/cm 2 ). These tests and results indicate that the mechanical properties of zirconium alloys are similar whether unirradiated or irradiated. Alloy B has shown the highest yield strength and tensile strength properties compared to other alloys in irradiated condition. Even though each of the zirconium alloys has a different alloying content, this content does not seem to affect the mechanical properties under an unirradiated condition and low fluence. And all the alloys have shown the tendency to increase in yield strength and ultimate tensile strength. Transverse specimens of each of the zirconium alloys have a slightly lower irradiation growth tendency than longitudinal specimens. However, for clear analysis of texture effects, further testing under higher irradiation conditions is needed

  12. Airport object extraction based on visual attention mechanism and parallel line detection

    Science.gov (United States)

    Lv, Jing; Lv, Wen; Zhang, Libao

    2017-10-01

    Target extraction is one of the important aspects in remote sensing image analysis and processing, which has wide applications in images compression, target tracking, target recognition and change detection. Among different targets, airport has attracted more and more attention due to its significance in military and civilian. In this paper, we propose a novel and reliable airport object extraction model combining visual attention mechanism and parallel line detection algorithm. First, a novel saliency analysis model for remote sensing images with airport region is proposed to complete statistical saliency feature analysis. The proposed model can precisely extract the most salient region and preferably suppress the background interference. Then, the prior geometric knowledge is analyzed and airport runways contained two parallel lines with similar length are detected efficiently. Finally, we use the improved Otsu threshold segmentation method to segment and extract the airport regions from the salient map of remote sensing images. The experimental results demonstrate that the proposed model outperforms existing saliency analysis models and shows good performance in the detection of the airport.

  13. [The molecular mechanisms of curcuma wenyujin extract-mediated inhibitory effects on human esophageal carcinoma cells in vitro].

    Science.gov (United States)

    Jing, Zhao; Zou, Hai-Zhou; Xu, Fang

    2012-09-01

    To study the molecular mechanisms of Curcuma Wenyujin extract-mediated inhibitory effects on human esophageal carcinoma cells. The Curcuma Wenyujin extract was obtained by supercritical carbon dioxide extraction. TE-1 cells were divided into 4 groups after adherence. 100 microL RMPI-1640 culture medium containing 0.1% DMSO was added in Group 1 as the control group. 100 microL 25, 50, and 100 mg/L Curcuma Wenyujin extract complete culture medium was respectively added in the rest 3 groups as the low, middle, and high dose Curcuma Wenyujin extract groups. The effects of different doses of Curcuma Wenyujin extract (25, 50, and 100 mg/L) on the proliferation of human esophageal carcinoma cell line TE-1 in vitro were analyzed by MTT assay. The gene expression profile was identified by cDNA microarrays in esophageal carcinoma TE-1 cells exposed to Curcuma Wenyujin extract for 48 h. The differential expression genes were further analyzed by Gene Ontology function analysis. Compared with the control group, MTT results showed that Curcuma Wenyujin extract significantly inhibited the proliferation of TE-1 cells in a dose-dependent manner (PCurcuma Wenyujin extract could inhibit the growth of human esophageal carcinoma cell line TE-1 in vitro. The molecular mechanisms might be associated with regulating genes expressions at multi-levels.

  14. Mechanical Properties of Nylon Harp Strings

    Science.gov (United States)

    Lynch-Aird, Nicolas; Woodhouse, Jim

    2017-01-01

    Monofilament nylon strings with a range of diameters, commercially marketed as harp strings, have been tested to establish their long-term mechanical properties. Once a string had settled into a desired stress state, the Young’s modulus was measured by a variety of methods that probe different time-scales. The modulus was found to be a strong function of testing frequency and also a strong function of stress. Strings were also subjected to cyclical variations of temperature, allowing various thermal properties to be measured: the coefficient of linear thermal expansion and the thermal sensitivities of tuning, Young’s modulus and density. The results revealed that the particular strings tested are divided into two groups with very different properties: stress-strain behaviour differing by a factor of two and some parametric sensitivities even having the opposite sign. Within each group, correlation studies allowed simple functional fits to be found to the key properties, which have the potential to be used in automated tuning systems for harp strings. PMID:28772858

  15. Mechanical Properties of Nylon Harp Strings

    Directory of Open Access Journals (Sweden)

    Nicolas Lynch-Aird

    2017-05-01

    Full Text Available Monofilament nylon strings with a range of diameters, commercially marketed as harp strings, have been tested to establish their long-term mechanical properties. Once a string had settled into a desired stress state, the Young’s modulus was measured by a variety of methods that probe different time-scales. The modulus was found to be a strong function of testing frequency and also a strong function of stress. Strings were also subjected to cyclical variations of temperature, allowing various thermal properties to be measured: the coefficient of linear thermal expansion and the thermal sensitivities of tuning, Young’s modulus and density. The results revealed that the particular strings tested are divided into two groups with very different properties: stress-strain behaviour differing by a factor of two and some parametric sensitivities even having the opposite sign. Within each group, correlation studies allowed simple functional fits to be found to the key properties, which have the potential to be used in automated tuning systems for harp strings.

  16. Effects of radiation-induced crosslinking on thermal and mechanical properties of poly(lactic acid) composites reinforced by basalt fiber

    International Nuclear Information System (INIS)

    Liu Meihua; Zhang Wanxi; Yin Yuan; Wei Wei; Zheng Chunbai; Deng Pengyang; Shen Shirley

    2013-01-01

    Poly (lactic acid)/ basalt fiber (PLA/BF) composites were prepared by melt blending with a cross-linking agent, triallyl isocyanurate (TAIC). The thermal and mechanical properties of the composites were investigated through gel fraction, heat defection temperature (HDT), tensile tests and scanning electron microscopy (SEM). Under certain conditions, the HDT of composites was dramatically increased to 140℃ after irradiation. Tensile properties were enhanced as well. Both these improvements were consistent with changes of the fracture morphology. Compatibilization and concomitant enhancement of the interfacial adhesive between the polymer matrix and the inorganic fiber were achieved as seen from SEM photos, as a result of the formation of co-crosslinking and grafting structures at the interface according to the determination of gelation extraction. (authors)

  17. Biometric feature extraction using local fractal auto-correlation

    International Nuclear Information System (INIS)

    Chen Xi; Zhang Jia-Shu

    2014-01-01

    Image texture feature extraction is a classical means for biometric recognition. To extract effective texture feature for matching, we utilize local fractal auto-correlation to construct an effective image texture descriptor. Three main steps are involved in the proposed scheme: (i) using two-dimensional Gabor filter to extract the texture features of biometric images; (ii) calculating the local fractal dimension of Gabor feature under different orientations and scales using fractal auto-correlation algorithm; and (iii) linking the local fractal dimension of Gabor feature under different orientations and scales into a big vector for matching. Experiments and analyses show our proposed scheme is an efficient biometric feature extraction approach. (condensed matter: structural, mechanical, and thermal properties)

  18. High energy radiation effects on mechanical properties of butyl rubber compounds

    International Nuclear Information System (INIS)

    Pozenato, Cristina A.; Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Lugao, Ademar B.

    2013-01-01

    The high energy radiation on butyl rubber compounds causes a number of chemical reactions that occur after initial ionization and excitation events. These reactions lead to changes in molecular mass of the polymer through scission and crosslinking of the molecules, being able to affect the physical and mechanical properties. Butyl rubber has excellent mechanical properties and oxidation resistance as well as low gas and water vapor permeability. Due to all these properties butyl rubber is widely used industrially and particularly in tires manufacturing. In accordance with various authors, the major effect of high energy, such as gamma rays in butyl rubber, is the yielding of free-radicals along with changes in mechanical properties. There were evaluated effects imparted from high energy radiation on mechanical properties of butyl rubber compounds, non-irradiated and irradiated with 25 kGy, 50 kGy, 150 kGy and 200 kGy. It was also observed a sharp reducing in stress rupture and elongation at break for doses higher than 50 kGy, pointing toward changes in polymeric chain along build-up of free radicals and consequent degradation. (author)

  19. A critical review on the spray drying of fruit extract: effect of additives on physicochemical properties.

    Science.gov (United States)

    Krishnaiah, Duduku; Nithyanandam, Rajesh; Sarbatly, Rosalam

    2014-01-01

    Spray drying accomplishes drying while particles are suspended in the air and is one method in the family of suspended particle processing systems, along with fluid-bed drying, flash drying, spray granulation, spray agglomeration, spray reaction, spray cooling, and spray absorption. This drying process is unique because it involves both particle formation and drying. The present paper reviews spray drying of fruit extracts, such as acai, acerola pomace, gac, mango, orange, cactus pear, opuntia stricta fruit, watermelon, and durian, and the effects of additives on physicochemical properties such as antioxidant activity, total carotenoid content, lycopene and β-carotene content, hygroscopy, moisture content, volatile retention, stickiness, color, solubility, glass transition temperature, bulk density, rehydration, caking, appearance under electron microscopy, and X-ray powder diffraction. The literature clearly demonstrates that the effect of additives and encapsulation play a vital role in determining the physicochemical properties of fruit extract powder. The technical difficulties in spray drying of fruit extracts can be overcome by modifying the spray dryer design. It also reveals that spray drying is a novel technology for converting fruit extract into powder form.

  20. Relationship between Magnetic and Mechanical Properties of Cermet Tools

    International Nuclear Information System (INIS)

    Ahn, Dong Gil; Lee, Jeong Hee

    2000-01-01

    The commercial cermet cutting tools consist of multi-carbide and a binder metal of iron group, such as cobalt and nickel which are ferromagnetic. In this paper, a new approach to evaluate the mechanical properties of TiCN based cermet by magnetic properties were studied in relation to binder content and sintering conditions. The experimental cermet was prepared using commercial composition with the other binder contents by PM process. It was found that the magnetic properties of the sintered cermets remarkably depended on the microstructure and the total carbon content. The magnetic saturation was proportional to increment of coercive force. At high carbon content in sintered cermet, the magnetic saturation was increased by decreasing the concentration of solutes such as W, Mo, Ti in Co-Ni binder. As the coercive force increases, the hardness usually increases. The strength and toughness of the cermet also increased with increasing the magnetic saturation. The measurement of magnetic properties made it possible to evaluate the mechanical properties in the cermet cutting tools

  1. Investigation on Mechanical Properties of Graphene Oxide reinforced GFRP

    Science.gov (United States)

    Arun, G. K.; Sreenivas, Nikhil; Brahma Reddy, Kesari; Sai Krishna Reddy, K.; Shashi Kumar, M. E.; Pramod, R.

    2018-02-01

    Graphene and E-glass fibres individually find a very wide field of applications because of their various mechanical and chemical properties. Recently graphene has attracted both academic and industrial interest because it can produce a dramatic improvement in properties at very low filler content. The primary interest of this venture is to investigate on Graphene reinforced polymer matrix nanocomposites and finding the mechanical properties. The composites were fabricated by Hand Lay Process and have been evaluated by the addition of Graphene with 1, 1.5, 2, 2.5 and 3 by weight% as reinforcement in composites. The theoretical and experimental results validate the increase in properties such as tensile strength, hardness and flexural strength with increase in weight proportions from 1% to 3% of graphene powder. It was observed that the composite material with 2.5% weight fraction of graphene yielded superior properties over other weight percentages. Graphene reinforced polymer matrix nanocomposites finds its major applications in the manufacture of aircraft bodies, ballistic missiles, sporting equipment, marine applications and extraterrestrial ventures.

  2. Plasma electrolytic oxidation of magnesium and its alloys: Mechanism, properties and applications

    Directory of Open Access Journals (Sweden)

    Gh. Barati Darband

    2017-03-01

    Full Text Available Plasma Electrolyte Oxidation (PEO process has increasingly been employed to improve magnesium surface properties by fabrication of an MgO-based coating. Originating from conventional anodizing procedures, this high-voltage process produces an adhesive ceramic film on the surface. The present article provides a comprehensive review around mechanisms of PEO coatings fabrication and their different properties. Due to complexity of PEO coatings formation, a complete explanation regarding fabrication mechanisms of PEO coatings has not yet been proposed; however, the most important advancements in the field of fabrication mechanisms of PEO coatings were gathered in this work. Mechanisms of PEO coatings fabrication on magnesium were reviewed considering voltage–time plots, optical spectrometry, acoustic emission spectrometry and electronic properties of the ceramic film. Afterwards, the coatings properties, affecting parameters and improvement strategies were discussed. In addition, corrosion resistance of coatings, important factors in corrosion resistance and methods for corrosion resistance improvement were considered. Tribological properties (important factors and improvement methods of coatings were also studied. Since magnesium and its alloys are broadly used in biological applications, the biological properties of PEO coatings, important factors in their biological performance and existing methods for improvement of coatings were explained. Addition of ceramic based nanoparticles and formation of nanocomposite coatings may considerably influence properties of plasma electrolyte oxidation coatings. Nanocomposite coatings properties and nanoparticles adsorption mechanisms were included in a separate sector. Another method to improve coatings properties is formation of hybrid coatings on PEO coatings which was discussed in the end.

  3. Manufacturing of hydrogel biomaterials with controlled mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Vedadghavami, Armin; Minooei, Farnaz; Mohammadi, Mohammad Hossein; Khetani, Sultan; Rezaei Kolahchi, Ahmad; Mashayekhan, Shohreh; Sanati-Nezhad, Amir

    2017-10-15

    Hydrogels have been recognized as crucial biomaterials in the field of tissue engineering, regenerative medicine, and drug delivery applications due to their specific characteristics. These biomaterials benefit from retaining a large amount of water, effective mass transfer, similarity to natural tissues and the ability to form different shapes. However, having relatively poor mechanical properties is a limiting factor associated with hydrogel biomaterials. Controlling the biomechanical properties of hydrogels is of paramount importance. In this work, firstly, mechanical characteristics of hydrogels and methods employed for characterizing these properties are explored. Subsequently, the most common approaches used for tuning mechanical properties of hydrogels including but are not limited to, interpenetrating polymer networks, nanocomposites, self-assembly techniques, and co-polymerization are discussed. The performance of different techniques used for tuning biomechanical properties of hydrogels is further compared. Such techniques involve lithography techniques for replication of tissues with complex mechanical profiles; microfluidic techniques applicable for generating gradients of mechanical properties in hydrogel biomaterials for engineering complex human tissues like intervertebral discs, osteochondral tissues, blood vessels and skin layers; and electrospinning techniques for synthesis of hybrid hydrogels and highly ordered fibers with tunable mechanical and biological properties. We finally discuss future perspectives and challenges for controlling biomimetic hydrogel materials possessing proper biomechanical properties. Hydrogels biomaterials are essential constituting components of engineered tissues with the applications in regenerative medicine and drug delivery. The mechanical properties of hydrogels play crucial roles in regulating the interactions between cells and extracellular matrix and directing the cells phenotype and genotype. Despite

  4. Metal-ceramic materials. Study and prediction of effective mechanical properties

    International Nuclear Information System (INIS)

    Karakulov, Valerii V.; Smolin, Igor Yu.

    2016-01-01

    Mechanical behavior of stochastic metal-ceramic composite materials was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites, whose structure consists of a metal matrix and randomly distributed ceramic inclusions, was numerically simulated. The results of the numerical simulation were used for evaluation of the effective elastic and strength properties of metal-ceramic materials with different parameters of the structure. The values of the effective mechanical properties of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites was determined.

  5. Mechanical properties of modified low cobalt powder metallurgy Udimet 700 type alloys

    Science.gov (United States)

    Harf, Fredric H.

    1989-01-01

    Eight superalloys derived from Udimet 700 were prepared by powder metallurgy, hot isostatically pressed, heat treated and their tensile and creep rupture properties determined. Several of these alloys displayed properties superior to those of Udimet 700 similarly prepared, in one case exceeding the creep rupture life tenfold. Filter clogging by extracted gamma prime, its measurement and significance are discussed in an appendix.

  6. Determining the Mechanical Properties of Lattice Block Structures

    Science.gov (United States)

    Wilmoth, Nathan

    2013-01-01

    Lattice block structures and shape memory alloys possess several traits ideal for solving intriguing new engineering problems in industries such as aerospace, military, and transportation. Recent testing at the NASA Glenn Research Center has investigated the material properties of lattice block structures cast from a conventional aerospace titanium alloy as well as lattice block structures cast from nickel-titanium shape memory alloy. The lattice block structures for both materials were sectioned into smaller subelements for tension and compression testing. The results from the cast conventional titanium material showed that the expected mechanical properties were maintained. The shape memory alloy material was found to be extremely brittle from the casting process and only compression testing was completed. Future shape memory alloy lattice block structures will utilize an adjusted material composition that will provide a better quality casting. The testing effort resulted in baseline mechanical property data from the conventional titanium material for comparison to shape memory alloy materials once suitable castings are available.

  7. Mechanical properties and microstructure of laser treated Al-Cu-Mg alloys

    NARCIS (Netherlands)

    Hosson, J.Th.M. De; Noordhuis, J.

    1993-01-01

    The mechanical properties and microstructural features of Al-Cu-Mg alloys were investigated, as exposed to laser treatments at various scan velocities. As far as the mechanical property is concerned a striking observation is a minimum in the hardness value at a laser scan velocity of 1/2 cm/s.

  8. Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro

    Science.gov (United States)

    Elosta, Abdulhakim; Slevin, Mark; Rahman, Khalid; Ahmed, Nessar

    2017-01-01

    Protein glycation involves formation of early (Amadori) and late advanced glycation endproducts (AGEs) together with free radicals via autoxidation of glucose and Amadori products. Glycation and increased free radical activity underlie the pathogenesis of diabetic complications. This study investigated whether aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro in a cell-free system. Proteins were glycated by incubation with sugars (glucose, methylglyoxal or ribose) ±5–15 mg/mL of aged and fresh garlic extracts. Advanced glycation endproducts were measured using SDS-PAGE gels and by ELISA whereas Amadori products were assessed by the fructosamine method. Colorimetric methods were used to assess antioxidant activity, free radical scavenging capacity, protein-bound carbonyl groups, thiol groups and metal chelation activities in addition to phenolic, total flavonoid and flavonol content of aged and fresh garlic extracts. Aged garlic inhibited AGEs by 56.4% compared to 33.5% for an equivalent concentration of fresh garlic extract. Similarly, aged garlic had a higher total phenolic content (129 ± 1.8 mg/g) compared to fresh garlic extract (56 ± 1.2 mg/g). Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract and is more suitable for use in future in vivo studies. PMID:28051097

  9. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys

    International Nuclear Information System (INIS)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-01-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti 2 Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti 2 Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (> 99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. - Highlights: • Hot extrusion refined the grain size and Ti 2 Cu phase significantly. • Hot extrusion increased the mechanical properties and the corrosion resistance. • The antibacterial properties was not affected by the hot process.

  10. Mechanical properties of ion implanted ceramic surfaces

    International Nuclear Information System (INIS)

    Burnett, P.J.

    1985-01-01

    This thesis investigates the mechanisms by which ion implantation can affect those surface mechanical properties of ceramics relevant to their tribological behaviour, specifically hardness and indentation fracture. A range of model materials (including single crystal Si, SiC, A1 2 0 3 , Mg0 and soda-lime-silica glass) have been implanted with a variety of ion species and at a range of ion energies. Significant changes have been found in both low-load microhardness and indentation fracture behaviour. The changes in hardness have been correlated with the evolution of an increasingly damaged and eventually amorphous thin surface layer together with the operation of radiation-, solid-solution- and precipitation-hardening mechanisms. Compressive surface stresses have been shown to be responsible for the observed changes in identation fracture behaviour. In addition, the levels of surface stress present have been correlated with the structure of the surface layer and a simple quantitative model proposed to explain the observed stress-relief upon amorphisation. Finally, the effects of ion implantation upon a range of polycrystalline ceramic materials has been investigated and the observed properties modifications compared and contrasted to those found for the model single crystal materials. (author)

  11. On a possible mechanism of the brain for responding to dynamical features extracted from input signals

    International Nuclear Information System (INIS)

    Liu Zengrong; Chen Guanrong

    2003-01-01

    Based on the general theory of nonlinear dynamical systems, a possible mechanism for responding to some dynamical features extracted from input signals in brain activities is described and discussed. This mechanism is first converted to a nonlinear dynamical configuration--a generalized synchronization of complex dynamical systems. Then, some general conditions for achieving such synchronizations are derived. It is shown that dynamical systems have potentials of producing different responses for different features extracted from various input signals, which may be used to describe brain activities. For illustration, some numerical examples are given with simulation figures

  12. Rheological and mechanical properties of recycled polyethylene films contaminated by biopolymer.

    Science.gov (United States)

    Gere, D; Czigany, T

    2018-06-01

    Nowadays, with the increasing amount of biopolymers used, it can be expected that biodegradable polymers (e.g. PLA, PBAT) may appear in the petrol-based polymer waste stream. However, their impact on the recycling processes is not known yet; moreover, the properties of the products made from contaminated polymer blends are not easily predictable. Therefore, our goal was to investigate the rheological and mechanical properties of synthetic and biopolymer compounds. We made different compounds from regranulates of mixed polyethylene film waste and original polylactic acid (PLA) by extruison, and injection molded specimens from the compounds. We investigated the rheological properties of the regranulates, and the mechanical properties of the samples. When PLA was added, the viscosity and specific volume of all the blends decreased, and mechanical properties (tensile strength, modulus, and impact strength) changed significantly. Young's modulus increased, while elongation at break and impact strength decreased with the increase of the weight fraction of PLA. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Antibacterial effects of Solanum tuberosum peel ethanol extract in vitro

    Directory of Open Access Journals (Sweden)

    Amanpour Raana

    2015-04-01

    Full Text Available Introduction: Today, medicinal plants are being widely used due to being natural, available, and cheaper than synthetic drugs and having minimum side effects. Since there were reports about the antibacterial properties of Solanum tuberosum (SE, the aim of this study was to investigate the antibacterial effects of SE ethanol extract in vitro condition on Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. Methods: Ethanol extract of SE peel was prepared by maceration method. Initially, antibacterial activity of ethanol extract of SE was qualitatively determined by disk diffusion test; then, the minimum inhibitory concentration and minimum bactericidal concentration were qualitatively determined by micro-dilution method. Results: SE peel extract had antibacterial properties and its effect was more pronounced on gram-positive bacteria, especially S. aureus (0.62±0.00 mg/ml. The extract had antibacterial activity on gram-negative bacteria, P. aeruginosa, too (8.33±2.88 mg/ml. Conclusion: SE peel extract has antibacterial activity and its effect on gram-positive bacteria was more pronounced than the investigated gram-negative bacteria. Therefore, it is suggested that SE peel constituent compounds be determined and to determine the exact mechanism of its antibacterial properties, and more comprehensive research be done to apply it, clinically.

  14. Mechanical properties of Nd-Ba-Cu-O bulk superconductors

    International Nuclear Information System (INIS)

    Matsui, Motohide; Sakai, Naomichi; Murakami, Masato; Osamura, Kozo

    2003-01-01

    We investigated the effects of Nd422 and Ag particles on the mechanical properties in Nd-Ba-Cu-O bulk superconductors. Both Nd422 and Ag particles were effective in decreasing the amount of microcracks running along the c direction. In the case of Nd422, however, excessive Nd422 addition enhanced the crack propagation, resulting in the degradation of mechanical strength. In the case of Ag addition, the beneficial effect of its ductile mechanical property was not observed. This was due to a relatively large size of Ag particles and low interfacial strength between Ag and Nd123 matrix. It was remarkable that the Weibull coefficient of the sample with Ag 2 O addition exceeded 13, which is reliable enough for practical engineering applications

  15. Physico-mechanical properties of naphthalene-acenaphthene eutectic system by different modes of solidification

    International Nuclear Information System (INIS)

    Sharma, B.L.; Gupta, S.; Tandon, S.; Kant, R.

    2008-01-01

    Anisotropic crystal growth kinetics from compositional melts encompassing the entire naphthalene-acenaphthene eutectic system, evidentially, evinces the dislocation mechanism. Rheological properties of eutectic phase melts at different temperatures explore the occurrence of molecular interactions emanating molecular clusters, rich in one phase or the other, in the eutectic melt. Microscopic studies confirm the crystalline faceted-faceted structure of the naphthalene-acenaphthene eutectic system. Implicit in the present work is the concept of strength-growth relationship that follows an identical form of the Weibull probability distribution curve. The curve exhibits two cut-off points corresponding to a lower strength limit in the slow and fast growth regions, and an upper strength limit in the moderate growth region. Relational essence between microstructural parameters essentially structuring morphology and excess thermodynamic functions implicitly governing molten state of the naphthalene-acenaphthene eutectic system is extracted

  16. Insight into the Extraction Mechanism of Americium(III) over Europium(III) with Pyridylpyrazole: A Relativistic Quantum Chemistry Study.

    Science.gov (United States)

    Kong, Xiang-He; Wu, Qun-Yan; Wang, Cong-Zhi; Lan, Jian-Hui; Chai, Zhi-Fang; Nie, Chang-Ming; Shi, Wei-Qun

    2018-05-10

    Separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is one of the most important steps in spent nuclear fuel reprocessing. However, it is very difficult and challenging to separate them due to their similar chemical properties. Recently the pyridylpyrazole ligand (PypzH) has been identified to show good separation ability toward Am(III) over Eu(III). In this work, to explore the Am(III)/Eu(III) separation mechanism of PypzH at the molecular level, the geometrical structures, bonding nature, and thermodynamic behaviors of the Am(III) and Eu(III) complexes with PypzH ligands modified by alkyl chains (Cn-PypzH, n = 2, 4, 8) have been systematically investigated using scalar relativistic density functional theory (DFT). According to the NBO (natural bonding orbital) and QTAIM (quantum theory of atoms in molecules) analyses, the M-N bonds exhibit a certain degree of covalent character, and more covalency appears in Am-N bonds compared to Eu-N bonds. Thermodynamic analyses suggest that the 1:1 extraction reaction, [M(NO 3 )(H 2 O) 6 ] 2+ + PypzH + 2NO 3 - → M(PypzH)(NO 3 ) 3 (H 2 O) + 5H 2 O, is the most suitable for Am(III)/Eu(III) separation. Furthermore, the extraction ability and the Am(III)/Eu(III) selectivity of the ligand PypzH is indeed enhanced by adding alkyl-substituted chains in agreement with experimental observations. Besides this, the nitrogen atom of pyrazole ring plays a more significant role in the extraction reactions related to Am(III)/Eu(III) separation compared to that of pyridine ring. This work could identify the mechanism of the Am(III)/Eu(III) selectivity of the ligand PypzH and provide valuable theoretical information for achieving an efficient Am(III)/Eu(III) separation process for spent nuclear fuel reprocessing.

  17. Mechanical properties of bioactive glass putty formulations

    NARCIS (Netherlands)

    van Gestel, N.A.P.; Geurts, J.A.P.; Hulsen, D.J.W.; Hofmann, S.; Ito, K.; van Rietbergen, B.; Arts, J.J.C.

    2016-01-01

    Introduction: Bioactive glass (BAG) has been studied widely and seems to be a very promising biomaterial in regeneration of large bone defects and osteomyelitis treatment, because of its bone bonding and antibacterial properties[1]-[5]. Its high stiffness could potentially also enable mechanical

  18. Different neurophysiological mechanisms underlying word and rule extraction from speech.

    Directory of Open Access Journals (Sweden)

    Ruth De Diego Balaguer

    Full Text Available The initial process of identifying words from spoken language and the detection of more subtle regularities underlying their structure are mandatory processes for language acquisition. Little is known about the cognitive mechanisms that allow us to extract these two types of information and their specific time-course of acquisition following initial contact with a new language. We report time-related electrophysiological changes that occurred while participants learned an artificial language. These changes strongly correlated with the discovery of the structural rules embedded in the words. These changes were clearly different from those related to word learning and occurred during the first minutes of exposition. There is a functional distinction in the nature of the electrophysiological signals during acquisition: an increase in negativity (N400 in the central electrodes is related to word-learning and development of a frontal positivity (P2 is related to rule-learning. In addition, the results of an online implicit and a post-learning test indicate that, once the rules of the language have been acquired, new words following the rule are processed as words of the language. By contrast, new words violating the rule induce syntax-related electrophysiological responses when inserted online in the stream (an early frontal negativity followed by a late posterior positivity and clear lexical effects when presented in isolation (N400 modulation. The present study provides direct evidence suggesting that the mechanisms to extract words and structural dependencies from continuous speech are functionally segregated. When these mechanisms are engaged, the electrophysiological marker associated with rule-learning appears very quickly, during the earliest phases of exposition to a new language.

  19. Mechanical Properties in a Bamboo Fiber/PBS Biodegradable Composite

    Science.gov (United States)

    Ogihara, Shinji; Okada, Akihisa; Kobayashi, Satoshi

    In recent years, biodegradable plastics which have low effect on environment have been developed. However, many of them have lower mechanical properties than conventional engineering plastics. Reinforcing them with a natural fiber is one of reinforcing methods without a loss of their biodegradability. In the present study, we use a bamboo fiber as the reinforcement and polybutylenesuccinate (PBS) as the matrix. We fabricate long fiber unidirectional composites and cross-ply laminate with different fiber weight fractions (10, 20, 30, 40 and 50wt%). We conduct tensile tests to evaluate the mechanical properties of these composites. In addition, we measure bamboo fiber strength distribution. We discuss the experimentally-obtained properties based on the mechanical properties of the constituent materials. Young's modulus and tensile strength in unidirectional composite and cross-ply laminate increase with increasing fiber weight fraction. However, the strain at fracture showed decreasing tendency. Young's modulus in fiber and fiber transverse directions are predictable by the rules of mixture. Tensile strength in fiber direction is lower than Curtin's prediction of strength which considers distribution of fiber strength. Young's modulus in cross-ply laminate is predictable by the laminate theory. However, analytical prediction of Poisson's ratio in cross-ply laminate by the laminate theory is lower than the experimental results.

  20. Cytotoxic, antioxidant and antimicrobial properties of red sweet pepper (Capsicum annuum L. var. Llanerón extracts: In vitro study

    Directory of Open Access Journals (Sweden)

    Rosa Raybaudi-Massilia

    2017-10-01

    Full Text Available Alcoholic and aqueous extracts were obtained from red sweet pepper (Capsicum annuum L. by different methodologies to evaluate their cytotoxic, antioxidant and antimicrobial properties. Alcoholic extracts (MFP, MSd, SFP, SDP, SSd from fresh red sweet pepper (FP and dry pulp (DP and seed (Sd were obtained by maceration (M and Soxhlet (S equipment using methanol as extraction solvent; whereas aqueous extracts (LFP, LSd were obtained by decoction followed by lyophilization (L. Human tumoral cell lines from breast (MCF-7 and SKBr3, prostate (PC3 and cervix (HeLa, and fibroblasts (as control were used to determine the cytotoxic properties by the MTT assay. Antioxidant and antimicrobial properties were determined by DPPH and disc diffusion method, respectively. The extracts SDP and SFP showed the higher cytotoxic activity. The SDP extract had a significant (P < 0.05 in-vitro effect on HeLa (1.9 ± 1.4 µg/mL and PC3 (< 1 µg/mL cells with a moderated impact on fibroblasts (26.1 ± 1.2 µg/mL; whereas, SFP had a significant (p < 0.05 effect on MCF-7 cell line (2.1 ± 1.2 µg/mL with a moderated impact on fibroblasts (25.9 ± 1.0 µg/mL. The higher antioxidant activity was found for MFP (80.3 ± 0.2% and SFP extracts (75.5 ± 0.5%. Mild antimicrobial activity was only observed for alcoholic extracts. The results showed the potential of red sweet pepper (C. annuum L. as a source of antioxidant and cytotoxic compounds, and suggest the need of further studies to isolate and characterize the bioactive compounds that impart those properties.

  1. Mechanical properties and microstructure of laser treated Al-Cu-Mg alloys

    OpenAIRE

    De Hosson , J.; Noordhuis , J.

    1993-01-01

    The mechanical properties and microstructural features of Al-Cu-Mg alloys were investigated, as exposed to laser treatments at various scan velocities. As far as the mechanical property is concerned a striking observation is a minimum in the hardness value at a laser scan velocity of 1/2 cm/s. Usually an increasing hardness with increasing laser scan velocities is reported in the literature. This remarkable property could be explained based on the microstructural features observed by transmis...

  2. Structural characterization and mechanical properties of polypropylene reinforced natural fibers

    Science.gov (United States)

    Karim, M. A. A.; Zaman, I.; Rozlan, S. A. M.; Berhanuddin, N. I. C.; Manshoor, B.; Mustapha, M. S.; Khalid, A.; Chan, S. W.

    2017-10-01

    Recently the development of natural fiber composite instead of synthetics fiber has lead to eco-friendly product manufacturing to meet various applications in the field of automotive, construction and manufacturing. The use of natural fibers offer an alternative to the reinforcing fibers because of their good mechanical properties, low density, renewability, and biodegradability. In this present research, the effects of maleic anhydride polypropylene (MAPP) on the mechanical properties and material characterization behaviour of kenaf fiber and coir fiber reinforced polypropylene were investigated. Different fractions of composites with 10wt%, 20wt% and 30wt% fiber content were prepared by using brabender mixer at 190°C. The 3wt% MAPP was added during the mixing. The composites were subsequently molded with injection molding to prepare the test specimens. The mechanical properties of the samples were investigated according to ISO 527 to determine the tensile strength and modulus. These results were also confirmed by the SEM machine observations of fracture surface of composites and FTIR analysis of the chemical structure. As the results, the presence of MAPP helps increasing the mechanical properties of both fibers and 30wt% kenaf fiber with 3wt% MAPP gives the best result compare to others.

  3. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

    Science.gov (United States)

    Li, Feng; Jiang, Xiaosong; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

    2018-04-16

    Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca₃(PO₄)₂, Ti x P y , and Ti₃O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

  4. Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Feng Li

    2018-04-01

    Full Text Available Biomaterial composites made of titanium and hydroxyapatite (HA powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD, back scattered electron imaging (BSE, scanning electron microscope (SEM equipped with energy dispersive spectrometer (EDS, electron probe microanalyzer (EPMA, and transmission electron microscope (TEM. The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca3(PO42, TixPy, and Ti3O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

  5. Urban Mining: Quality and quantity of recyclable and recoverable material mechanically and physically extractable from residual waste

    International Nuclear Information System (INIS)

    Di Maria, Francesco; Micale, Caterina; Sordi, Alessio; Cirulli, Giuseppe; Marionni, Moreno

    2013-01-01

    Highlights: • Material recycling and recovery from residual waste by physical and mechanical process has been investigated. • About 6% of recyclable can be extracted by NIR and 2-3Dimension selector. • Another 2% of construction materials can be extracted by adopting modified soil washing process. • Extracted material quality is quite high even some residual heavy metal have been detected by leaching test. - Abstract: The mechanically sorted dry fraction (MSDF) and Fines (<20 mm) arising from the mechanical biological treatment of residual municipal solid waste (RMSW) contains respectively about 11% w/w each of recyclable and recoverable materials. Processing a large sample of MSDF in an existing full-scale mechanical sorting facility equipped with near infrared and 2-3 dimensional selectors led to the extraction of about 6% w/w of recyclables with respect to the RMSW weight. Maximum selection efficiency was achieved for metals, about 98% w/w, whereas it was lower for Waste Electrical and Electronic Equipment (WEEE), about 2% w/w. After a simulated lab scale soil washing treatment it was possible to extract about 2% w/w of inert exploitable substances recoverable as construction materials, with respect to the amount of RMSW. The passing curve showed that inert materials were mainly sand with a particle size ranging from 0.063 to 2 mm. Leaching tests showed quite low heavy metal concentrations with the exception of the particles retained by the 0.5 mm sieve. A minimum pollutant concentration was in the leachate from the 10 and 20 mm particle size fractions

  6. On the Mechanical Properties of Chiral Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Mahnaz Zakeri

    2013-12-01

    Full Text Available Carbon nanotubes (CNTs are specific structures with valuable characteristics. In general, the structure of each nanotube is defined by a unique chiral vector. In this paper, different structures of short single-walled CNTs are simulated and their mechanical properties are determined using finite element method. For this aim, a simple algorithm is presented which is able to model the geometry of single-walled CNTs with any desired structure based on nano-scale continuum mechanics approach. By changing the chiral angle from 0 to 30 degree for constant length to radius ratio, the effect of nanotube chirality on its mechanical properties is evaluated. It is observed that the tensile modulus of CNTs changes between 0.93-1.02 TPa for different structures, and it can be higher for chiral structures than zigzag and armchair ones. Also, for different chiral angles, the bending modulus changes between 0.76-0.82 TPa, while the torsional modulus varies in the range of 0.283-0.301TPa.

  7. Effects of Stress Concentration on the Mechanical Properties of Carbon Fiber Reinforced Plastic

    Directory of Open Access Journals (Sweden)

    Ryo Naito

    2017-03-01

    Full Text Available Mechanical properties of conventional CFRP plates with small holes were investigated systematically. Those artificial holes are considered to be rivet connection between CFRP and other materials. The machining holes were employed with different number (n=0-5 and different mode, e.g., parallel (Sample A, 45 degree (Sample B and perpendicular (Sample C against the loading direction. To understand the mechanical properties of the CFRP plates clearly, tensile tests and failure analysis were conducted experimentally. Excellent mechanical properties were obtained for Sample A, compared to the other ones. This is due to the different size of the cross-section area in the specimen. With increasing the number of rivet hole, the mechanical properties were lineally decreasing. Such mechanical properties were analyzed by direct observation using a high speed camera, i.e., in-situ measurement of deformation during the tensile loading was carried

  8. Optimized extraction conditions from high power-ECRIS by dedicated dielectric structures

    International Nuclear Information System (INIS)

    Schachter, L.; Dobrescu, S.; Stiebing, K.E.

    2012-01-01

    The MD-method of enhancing the ion output from ECR ion sources is well established and basically works via two mechanisms, the regenerative injection of cold electrons from an emissive dielectric layer on the plasma chamber walls and via the cutting of compensating wall currents, which results in an improved ion extraction from the plasma. As this extraction from the plasma becomes a more and more challenging issue for modern ECRIS installations with high microwave power input, a series of experiments was carried out at the 14 GHz ECRIS of the Institut fuer Kernphysik in Frankfurt/Main, Germany (IKF). In contrast to our earlier work, in these experiments emphasis was put on the second of the above mechanisms namely to influence the sheath potential at the extraction by structures with special dielectric properties. Two different types of dielectric structures, Tantalum-oxide and Aluminium oxide (the latter also being used for the MD-method) with dramatically different electrical properties were mounted on the extraction electrode of the IKF-ECRIS, facing the plasma. For both structures an increase of the extracted ion beam currents for middle and high charge states by 60-80 % was observed. The method can also be applied to other ECR ion sources for increasing the extracted ion beam performances. The paper is followed by the slides of the presentation. (authors)

  9. Effect of thermo-mechanical treatments on the microstructure and mechanical properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Oksiuta, Z.; Mueller, P.; Spaetig, P.; Baluc, N.

    2011-01-01

    The Fe-14Cr-2W-0.3Ti-0.3Y 2 O 3 oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steel was fabricated by mechanical alloying of a pre-alloyed, gas atomised powder with yttria nano-particles, followed by hot isostatic pressing and thermo-mechanical treatments (TMTs). Two kinds of TMT were applied: (i) hot pressing, or (ii) hot rolling, both followed by annealing in vacuum at 850 deg. C. The use of a thermo-mechanical treatment was found to yield strong improvement in the microstructure and mechanical properties of the ODS RAF steel. In particular, hot pressing leads to microstructure refinement, equiaxed grains without texture, and an improvement in Charpy impact properties, especially in terms of the upper shelf energy (about 4.5 J). Hot rolling leads to elongated grains in the rolling direction, with a grain size ratio of 6:1, higher tensile strength and reasonable ductility up to 750 deg. C, and better Charpy impact properties, especially in terms of the ductile-to-brittle transition temperature (about 55 deg. C).

  10. Effect of thermo-mechanical treatments on the microstructure and mechanical properties of an ODS ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Oksiuta, Z., E-mail: oksiuta@pb.edu.pl [Bialystok Technical University, Mechanical Department, Wiejska 45c, 15-351 Bialystok (Poland); Mueller, P.; Spaetig, P.; Baluc, N. [Ecole Polytechnique Federale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, 5232 Villigen PSI (Switzerland)

    2011-05-15

    The Fe-14Cr-2W-0.3Ti-0.3Y{sub 2}O{sub 3} oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steel was fabricated by mechanical alloying of a pre-alloyed, gas atomised powder with yttria nano-particles, followed by hot isostatic pressing and thermo-mechanical treatments (TMTs). Two kinds of TMT were applied: (i) hot pressing, or (ii) hot rolling, both followed by annealing in vacuum at 850 deg. C. The use of a thermo-mechanical treatment was found to yield strong improvement in the microstructure and mechanical properties of the ODS RAF steel. In particular, hot pressing leads to microstructure refinement, equiaxed grains without texture, and an improvement in Charpy impact properties, especially in terms of the upper shelf energy (about 4.5 J). Hot rolling leads to elongated grains in the rolling direction, with a grain size ratio of 6:1, higher tensile strength and reasonable ductility up to 750 deg. C, and better Charpy impact properties, especially in terms of the ductile-to-brittle transition temperature (about 55 deg. C).

  11. Evaluation of the anti-diabetic properties of Mucuna pruriens seed extract.

    Science.gov (United States)

    Majekodunmi, Stephen O; Oyagbemi, Ademola A; Umukoro, Solomon; Odeku, Oluwatoyin A

    2011-08-01

    To explore the antidiabetic properties of Mucuna pruriens(M. pruriens). Diabetes was induced in Wistar rats by single intravenous injection of 120 mg/kg of alloxan monohydrate and different doses of the extract were administered to diabetic rats. The blood glucose level was determined using a glucometer and results were compared with normal and untreated diabetic rats. The acute toxicity was also determined in albino mice. Results showed that the administration of 5, 10, 20, 30, 40, 50, and 100 mg/kg of the crude ethanolic extract of M. pruriens seeds to alloxan-induced diabetic rats (plasma glucose > 450 mg/dL) resulted in 18.6%, 24.9%, 30.8%, 41.4%, 49.7%, 53.1% and 55.4% reduction, respectively in blood glucose level of the diabetic rats after 8h of treatment while the administration of glibenclamide (5 mg/kg/day) resulted in 59.7% reduction. Chronic administration of the extract resulted in a significant dose dependent reduction in the blood glucose level (Ppruriens seeds resides in the methanolic and ethanolic fractions of the extract. Acute toxicity studies indicated that the extract was relatively safe at low doses, although some adverse reactions were observed at higher doses (8-32 mg/kg body weight), no death was recorded. Furthermore, oral administration of M. pruriens seed extract also significantly reduced the weight loss associated with diabetes. The study clearly supports the traditional use of M. pruriens for the treatment of diabetes and indicates that the plant could be a good source of potent antidiabetic drug. Copyright © 2011 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  12. Comparison study of moisture content, colour properties and essential oil compounds extracted by hydrodistillation and supercritical fluid extraction between stem and leaves of lemongrass (Cymbopogun citratus)

    Science.gov (United States)

    Kamaruddin, Shazlin; Mustapha, Wan Aida Wan; Haiyee, Zaibunnisa Abdul

    2018-04-01

    The objectives of this study were to compare the properties of moisture content, colour and essential oil compounds between stem and leaves of lemongrass (Cymbopogun citratus). The essential oil was extracted using two different methods which are hydrodistillation and supercritical fluid extraction (SFE). There was no significant difference of moisture content between stem and leaves of lemongrass. The lightness (L) and yellowness (+b) values of the stems were significantly higher (pleaves. The highest yield of essential oil was obtained by extraction using supercritical fluid extraction (SFE) in leaves (˜ 0.7%) by treatment at 1700psi and 50°C. The main compound of extracted essential oil was citral (geranial and neral).

  13. Greener synthesis of magnetite nanoparticles using green tea extract and their magnetic properties

    Science.gov (United States)

    Karade, V. C.; Waifalkar, P. P.; Dongle, T. D.; Sahoo, Subasa C.; Kollu, P.; Patil, P. S.; Patil, P. B.

    2017-09-01

    The facile green synthesis method has been employed for the synthesis of biocompatible Fe3O4 magnetic nanoparticles (MNPs) using green tea extract. The effective reduction of ferric ions (Fe3+) were done using an aqueous green tea extract where it acts as reducing as well as capping agent. The effect of iron precursor to green tea extract ratio and reaction temperature was studied. The MNPs were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic light scattering and vibrating sample magnetometer. It was observed that the reaction temperature strongly affects the magnetic and structural properties of MNPs. The magnetic measurements study showed that Fe3O4 MNPs are superparamagnetic at 300 K, while at 60 K have ferromagnetic as well as superparamagnetic contributions.

  14. The fracture properties and toughening mechanisms of bone and dentin

    Science.gov (United States)

    Koester, Kurt John

    The mechanical properties of bone and dentin and in particular their fracture properties, are the subject of intense research. The relevance of these properties is increasing as our population ages and fracture incidence impacts the lives of a greater portion of the population. A robust framework is needed to understand the fracture properties of bone and dentin to guide researchers as they attempt to characterize the effects of aging, disease, and pharmaceutical treatments on the properties of these mineralized tissues. In the present work, this framework is provided and applied to human bone, human dentin, and animal bone. In situ electron microscopy was also used to identify the salient toughening mechanisms in bone and dentin. It was found that bone and dentin are extrinsically toughened materials and consequently their fracture properties are best characterized utilizing a crack-growth resistance approach. A description of the different mechanical measurements commonly employed when using small animal models (rats and mice) to evaluate the influence of drug therapies on bone fragility is provided. A study where these properties were measured for a large population of wild-type rats and mice was also conducted. Given my findings, it was determined that for the most complete understanding of small animal bone it was necessary to measure strength and toughness. Strength measurements probe the flaw distribution and toughness measurements to evaluate the resistance to facture in the presence of a single dominant worst-case flaw.

  15. Physicochemical properties of soybean oil extracted from γ-irradiated soybeans

    International Nuclear Information System (INIS)

    Myung-Woo Byun; Il-Jun Kang; Joong-Ho Kwon; Hayashi, Yukako; Mori, Tomohiko

    1996-01-01

    Physicochemical properties of soybean oil extracted from γ-irradiated soybeans (0-10 kGy) were investigated. No significant changes were observed in the total lipid content, fatty acid composition, acid value, peroxide value and trans fatty acid content at different irradiation doses. A tendency toward increased induction period was observed as irradiation dose increased. At higher dose levels than 10 kGy, n-hexanal increased remarkably as dose levels increased, showing the possibility of a chemical index for over-dose irradiation in soybeans. (author)

  16. Physiochemical properties of soybean oil extracted from γ-irradiated soybeans

    International Nuclear Information System (INIS)

    Byun, M.W.; Kang, I.J.; Kwon, J.H.; Hayashi, Y.; Mori, T.

    1995-01-01

    Physicochemical properties of soybean oil extracted from γ-irradiated soybeans (0-10kGy) were investigated. No significant changes were observed in the total lipid content, fatty acid composition, acid value, peroxide value and trans fatty acid content at different irradiation doses. A tendency toward increased induction period was observed as irradiation dose increased. At higher dose levels than 10 kGy, n-hexagonal content remarkably increased as dose levels increased, showing the possibility of a chemical index for over-dose irradiation in soybeans. (Author)

  17. Antimicrobial and Cytotoxic Activities of Extracts from Laurus nobilis Leaves

    KAUST Repository

    Felemban, Shaza

    2011-05-01

    The cytotoxic activity and antimicrobial properties of crude extracts from Laurus nobilis were investigated. With the use of the organic solvents, methanol and ethanol, crude extracts were obtained. To determine the availability of active bio‐compounds, an analysis using liquid chromatography was conducted. The crude extract was also tested for antimicrobial activity. The disc diffusion method was used against the bacterium Escherichia coli. The results showed a weak antimicrobial activity against E. coli. For cytotoxicity testing, the crude extract was studied on four cell-­lines: human breast adenocarcinoma, human embryonic kidney, HeLa (human cervical adenocarcinoma), and human lung fibroblast. From the alamarBlue® assay results, the extracts most potently affected the cell-­lines of human breast adenocarcinoma and human embryonic kidney. Using the lactate dehydrogenase (LDH) assay, an effect on human embryonic kidney was most prominent. With these findings, a suggestion that the crude extract of Laurus nobilis may have antiproliferative properties is put forth, with the possibility of this mechanism being induction of apoptosis with the involvement of Nuclear Factor Kappa κB (NF κB).

  18. Mechanical properties of depleted uranium-2 w/o molybdenum alloy

    International Nuclear Information System (INIS)

    Deel, O.L.; Burian, R.J.

    1979-01-01

    The primary objective of this program is to develop data and techniques for determining the dynamic impact response of radioactive-material shipping-container systems for environmental control and safety overview and assessment. One phase of this program is the dynamic testing of 1/8-, 1/4-, and 1/2-scale models of uranium-shielded truck casks. These linearly scaled models are fabricated from the same materials typically used in full-size prototype casks. In order to analytically evaluate the results of dynamic tests, it is necessary to know the mechanical properties of the materials of construction. Since the properties of cast uranium--molybdenum alloys vary significantly with casting and heat-treating techniques, it is necessary to fully characterize the mechanical properties of the uranium used in the model tests. This report presents the results of these studies. The uranium alloy exhibited a tensile strength equal to or greater than that reported by others. As indicated by the percentage of elongation and reduction in area, the ductility was lower. Comparative data for the other mechanical properties measured were not found in the literature

  19. Mechanical Properties of Nanostructured Materials Determined Through Molecular Modeling Techniques

    Science.gov (United States)

    Clancy, Thomas C.; Gates, Thomas S.

    2005-01-01

    The potential for gains in material properties over conventional materials has motivated an effort to develop novel nanostructured materials for aerospace applications. These novel materials typically consist of a polymer matrix reinforced with particles on the nanometer length scale. In this study, molecular modeling is used to construct fully atomistic models of a carbon nanotube embedded in an epoxy polymer matrix. Functionalization of the nanotube which consists of the introduction of direct chemical bonding between the polymer matrix and the nanotube, hence providing a load transfer mechanism, is systematically varied. The relative effectiveness of functionalization in a nanostructured material may depend on a variety of factors related to the details of the chemical bonding and the polymer structure at the nanotube-polymer interface. The objective of this modeling is to determine what influence the details of functionalization of the carbon nanotube with the polymer matrix has on the resulting mechanical properties. By considering a range of degree of functionalization, the structure-property relationships of these materials is examined and mechanical properties of these models are calculated using standard techniques.

  20. Determination of the Mechanical Properties of Rubber by FT-NIR

    OpenAIRE

    Pornprasit, Rattapol; Pornprasit, Philaiwan; Boonma, Pruet; Natwichai, Juggapong

    2016-01-01

    Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), and ethylene propylene diene monomer (EPDM), were evaluated using a near infrared (NIR) spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-...