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排序方式: 共有1314条查询结果,搜索用时 62 毫秒
71.
This research explored the possible application of pressurised carbon dioxide (P CO(2)), a promising non-thermal sterilisation technique, for the treatment of sewage sludge (SS) before anaerobic digestion to inactivate pathogenic microorganisms. Escherichia coli was selected as the test organism and was isolated from SS and maintained in pure culture. The growth curve of the isolated strain was determined by measuring the optical density (OD) in liquid culture medium and relating this information to the spread plate count so that a culture of known cell density could be grown for optimisation experiments. Inactivation of E. coli was enhanced by increase in pressure (1,500, 2,000 and 2,800 kPa) and treatment time (from 0.75 to 24 h). A short exposure time at high pressure was sufficient to provide a degree of inactivation which could also be achieved by longer exposure at lower pressure. Complete inactivation (8 log(10) reduction) was possible at all three pressures. scanning (SEM) and transmission (TEM) electron microscopy studies of E. coli treated with P CO(2) revealed that the cell walls were ruptured, and the cytoplasm was unevenly distributed and had lost its density, indicating the possible leakage of intracellular substances. 相似文献
72.
Tiziana Nardo Valeria Chiono Piergiorgio Gentile Maryam Tabrizian Gianluca Ciardelli 《国际聚合物材料杂志》2016,65(14):741-750
Poly(DL-lactide-co-ε-caprolactone) (PLCL) and poly(DL-lactide-co-glycolide) (PLGA) blends of various compositions were prepared. Fractured sections of PLCL/PLGA blends did not evidence phase separation and blend glass transition temperatures suggested some degree of blend compatibility. The elastic modulus showed a negative deviation from the additive law of mixture. Superior biocompatibility in terms of fibroblast NIH 3T3 cell adhesion and proliferation, better mechanical properties, and a more homogeneous phase were obtained with PLCL/PLGA 25/75 blend. Rapid degradation of PLCL phase (4–8 weeks) in PLCL/PLGA 25/75 blend led to a porous structure, which makes it a potential candidate for drug delivery systems. 相似文献
73.
Maryam Abrishamkar Motahareh Barootkoob 《International Journal of Hydrogen Energy》2017,42(37):23821-23825
This study aimed to investigate the application of nano ZSM-5 zeolite for preparation of modified carbone paste electrode for electrocatalytic oxidation of formaldehyde. The electrochemical behavior of modified carbon paste electrodes in the forms of Fe/FeZSM-5CPE and unmodified carbon paste electrode were studied using cyclic voltammetric and chronoamprometric techniques. The obtained results show that the modified carbon paste electrode (Fe/FeZSM-5CPE) is the suitable electrode for electrooxidation of formaldehyde in the acidic solution. The transfer coefficient and current density for formaldehyde were calculated 0.23 and 19.8 mA/cm2, respectively. The rate constant for catalytic reaction was calculated as 3.6 × 103 cm3 s?1 mol?1 via Cottrell equation. 相似文献
74.
Maryam Mehrnezhad Abbas Ghaemi Bafghi Ahad Harati Ehsan Toreini 《International Journal of Information Security》2017,16(2):133-149
This paper introduces pictorial intelligent system for human identification (PiSHi), an image-based captcha which uses three human cognitive abilities to distinguish humans from machines. The first is the human ability to easily recognise the image’s upright orientation. The second is the human brain’s ability in recognising a picture’s content when it is only partially visible. And the third is the human ability in unconscious decision making when encountering pictorial challenges. This work models such complicated human patterns in problem solving for the first time. In order to extract these behavioural patterns and save them in a pattern database, we have implemented our own captcha and performed a series of experiments. PiSHi’s interface presents the user with a set of distorted pictures and asks her to click on the upright orientation of all the pictures in any preferred order. Next, it captures the user’s interaction patterns, compares them with the ones saved in the pattern database, and grants her a corresponding credit. Based on this credit, the user either passes or fails the test, and participates in updating the picture database. Our experiments indicate that human users can solve our proposed captcha effectively—with an accuracy of 99.44 %. Besides, our proposed system is secure against several types of attacks including random guessing and reverse image search engines. The results offer the possibility of utilising the identified human behavioural models in practical captchas. 相似文献
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This paper presents a developed geometric approach for deriving the typologies and geometries of discontinuous double-shell
domes in Islamic architecture. Common geometric attributes are created using a corpus of twenty one domes that were built
in the Middle East and Central Asia, beginning from the early through to the late Islamic periods. An outline of the origin
and development of the discontinuous double-shell domes and their morphological features are addressed. Using the al-Kashi
geometrical essences, a four-centered profile as an initial shape is constructed based on new geometric parameters to deduce
the geometric commonalities of the two aspects of formal language (typologies and geometries) of such domes. Common geometric
prototypes for typical profiles shared by the study cases are generated and formulated according to a proposed system. The
theoretical frame work for the formal language of discontinuous double-shell dome architecture is structured to indicate a
moderate development of this sort of Islamic domes and highlight the specific geometric relationship between the Islamic domical
configurations and practical mathematic rules for many decades. It can also be established a basic approach for considering
the geometric compositional designs and the typological derivations of the other eastern domes. 相似文献
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Maryam Tavafoghi Joseph M. Kinsella Cé Guinto Gamys Mathilde Gosselin Yaoyao Fiona Zhao 《Ceramics International》2018,44(15):17612-17622
Hydroxyapatite (HA, Ca5(PO4)3OH) has been extensively used for bone implantation due to its similarity to the mineral component of bone, which makes it strongly osteoconductive. However, HA has low resorbability, and it is difficult to replace by a newly regenerated bone. Si doping can enhance the resorbability of HA by modifying its crystal structure. Here, we developed a simple thermal technique for preparing Si-doped HA from silica (SiO2) and HA precursors, both of which are inexpensive and commercially available. This method included the physical binding of SiO2 and HA particles, followed by pressing and sintering the mixture at an elevated temperature, which enhanced the atomic diffusion of Si into HA unit cells. We also evaluated the simulated body fluid (SBF) activity of the Si-doped HA prepared by this technique and showed that it significantly had higher resorbability and mineralizing potential compared to the pure HA. Our experimental design including, the individual precipitation and resorption assays enabled us to explain the mechanism behind the improved activity of Si-doped HA in SBF. This was attributed to the formation of new phases, such as β-tricalcium phosphate (β-TCP) and calcium silicate (Ca2SiO4) with higher solubility than HA on the SiO2-contating HA during the sintering stage. This can provide some guidelines for designing new calcium phosphate-based materials for hard tissue engineering applications. 相似文献