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Process conditions for preparing well-defined nano- and microparticles as delivery systems of alkyl gallates

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Particuology 2019年第3期17卷 105-116页

作者： Asma Chebil denis Funfschilling Jean-Luc Six Cécile Nouvel Alain Durand Michèle Léonard Universite de Lorraine CNRS LCPM F-54000 Nancy France Universite de Lorraine CNRS LRGP F-54000 Nancy France Universite de Strasbourg CNRS ICube F-67000 Strasbourg France

Dextran-covered poly(D,L-lactide) (PLA) nano-and microparticles were prepared using an emulsion/solvent evaporation (or diffusion) process for the encapsulation of alkyl gallates (AGs).In the first step,a solution of PLA and AG in ethyl acetate was emulsified to give an aqueous phase containing a hydrophobically modified dextran,which acted as a *** second step involved solvent evaporation or *** emulsification conditions were varied,which allowed for the preparation of nanoand microparticle suspensions covering a wide range of surface-average particle diameters from 0.1 μm (sonication) to 500 μm (stirring with a magnetic bar),with narrow and reproducible size *** microfluidic emulsification in a flow-focusing system led to well-defined microparticles,in the 10-50 μm *** loaded with octyl gallate (OG) and nonyl gallate (NG) were obtained using the three processes,and we showed that the encapsulation efficiency of OG and NG varied significantly depending on the emulsification *** effect of particle size on the mechanism of in vitro release of encapsulated AGs was *** kinetics of release were controlled either by Fickian diffusion within the solid core or swelling and hydrolytic degradation of the PLA matrix,depending on the pH of the external medium.

关键词： Emulsion/solvent evaporation Dextran Poly(D.L-lactide) Encapsulation Release Alkyl gallate

Theoretical Analysis of the Fluctuation Theorem Applied to Electric Circuits

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Communications in Theoretical Physics 2014年第10期61卷 476-484页

作者： Charlotte F.Petersen Elmars Krausz denis J.Evans Stephen R.Williams Research School of Chemistry Australian National UniversityCanberraACT 0200Australia

We carry out a theoretical analysis of the fluctuations in the Johnson–Nyquist noise in an RC electric circuit being driven by a non-ideal constant current source. Using the appropriate Langevin equation, we derive the fluctuation theorem for the system. This analysis exhibits some interesting features. Firstly, the average of the dissipation function is not necessarily just an instantaneous entropy production, i.e. the work being done on the circuit by the external power source divided by the ambient temperature. Secondly, by appropriate selection of the values for the circuit components,the transient response of the system can be made identical to the nonequilibrium steady state response. In the limit of an ideal current source, the average of the dissipation function reduces to the entropy production. Our analysis accurately reproduces published experimental results.

关键词： circuit analysis fluctuation theorems statistical machanics Johnson noise

Investigation of the performance of a pilot-scale barrel atmospheric plasma system for plasma activation of polymer particles

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Nanotechnology and Precision Engineering 2019年第1期2卷 1-7页

作者： Hisham M.Abourayana Peter J.Dobbyn Pat Whyte denis P.Dowling Surface Engineering Group School of Mechanical and Materials Engineering University College Dublin Irish Micro Mouldings Inverin Co.

This study reports the development and performance of a pilot-scale barrel atmospheric plasma reactor for the atmospheric plasma activation treatment of polymer particles. The polymer particles treated included acrylonitrile butadiene styrene(ABS) and polypropylene(PP). These particles had diameters in the range of 3–5 mm. The initial studies were carried out using a laboratory-scale barrel reactor designed to treat polymer particle batch sizes of 20 g. A pilot-scale reactor that could treat 500 g particle batch sizes was then developed to facilitate pre-industrial-scale treatments. The effect of operating pulse density modulation(PDM) in the range 10%–100% and plasma treatment time on the level of activation of the treated polymers were then investigated. ABS revealed a larger decrease in water contact angle compared with PP after plasma treatment under the same conditions. The optimal treatment time of ABS(400 g of polymer particles) in the pilot-scale reactor was 15 min. The plasma-activated polymer particles were used to fabricate dog-bone polymer parts through injection *** testing of the resulting dog-bone polymer parts revealed a 10.5% increase in tensile strength compared with those fabricated using non-activated polymer particles.

关键词： Atmospheric pressure plasma Barrel plasma reactor Polymer particles Water contact angle X-ray photoelectron spectroscopy Injection moulding

Reduction of environmental pollution by using RTK-navigation in soil cultivation

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International Journal of Agricultural and Biological Engineering 2019年第5期12卷 173-178页

作者： Damijan Kelc denis Stajnko Peter Berk Jurij Rakun Peter Vindiš Miran Lakota Faculty of Agriculture and Life Sciences University of MariborPivola 102311 HočeSlovenia

The concept of precision farming is wide,and it represents the efficiency which is achieved with the help of *** the navigation of field machines,the RTK(Real Time Kinematic)navigation is *** order to verify the positive effects in practice,RTK navigation system equipped with Fentd 828 was applied to test the width of overlap,and fuel and time that could be saved compared with manual *** experiment was conducted on two areas of land size of 172 m×58 m with two working machines width 3 m and 6 *** indicated that 15.7%of the time and 8.66%of the fuel were saved on a working machine of 3 meters width,and 12.6%of the time and 8.28%of the fuel were saved on a working machine of 6 m *** width of the overlap represent 10%of the working width of the machine,and with the method of turning,which RTK navigation allows,additional time was *** footprint,CO2 emissions and global warming potential(GWP)was estimated under different guiding *** largest footprint was related to manual tillage with 3 m width working machine,while estimation on CO2(kg)emissions and GWP obtained the same *** use of precision agriculture technologies allows better planning and analyzing of working *** air,water and soil pollution are less intensive.

关键词： precision farming RTK technology ecological footprint environmental pollution tillage

Modeling of Crack Development Associated with Proppant Hydraulic Fracturing in a Clay-Carbonate Oil Deposit

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Fluid Dynamics & Materials Processing 2023年第2期19卷 273-284页

作者： Sergey Galkin Ian Savitckii denis Shustov Artyom Kukhtinskii Boris Osovetsky Alexander Votinov Perm National Research Polytechnic University PermRussian Perm State National Research University PermRussian PermNIPIneft Branch of LUKOIL-Engineering LLC PermRussian

Survey and novel research data are used in the present study to classify/identify the lithological type of Verey age reservoirs’*** is shown how the use of X-ray tomography can clarify the degree of heterogeneity,porosity and permeability of these *** data are then used to elaborate a model of hydraulic *** resulting software can take into account the properties of proppant and breakdown fluid,thermal reservoir conditions,oil properties,well design data and even the filtration and elastic-mechanical properties of the *** of hydraulic fracturing crack formation are carried out and the results are compared with the data on hydraulic fracturing crack at standard *** differences in crack formation in standard and lithotype models are *** is shown that the average width of the crack development for the lithotype model is 2.3 times higher than that for the standard ***,the coverage of crack development in height for the lithotype model is almost 2 times less than that for the standard *** estimated fracture half-length for the lithotype model is 13.3%less than that of for the standard model.A higher dimensionless fracture conductivity is also obtained for the lithotype *** is concluded that the proposed approach can increase the reliability of hydraulic fracturing crack models.

关键词： Proppant hydraulic fracturing X-ray tomography porosity permeability fractured reservoir well logging carbonate deposits

Quark-Novae Ia in the Hubble diagram: implications for dark energy

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Research in Astronomy and Astrophysics 2014年第5期14卷 497-519页

作者： Rachid Ouyed Nico Koning denis Leahy Jan E.Staff Daniel T.Cassidy Department of Physics and Astronomy University of Calgary 2500 University Drive NWCalgary Alberta T2N 1N4 Canada Department of Physics and Astronomy Macquarie University NSW 2109 Australia Department of Engineering Physics McMaster University Hamilton Ontario L8S 4L7 Canada

The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae （SNe） as standard candles. The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves. The use of Type-Ia SNe as standard candles rests on the assumption that their properties （and this correlation） do not vary with redshift. We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system, which forms a Quark-Nova Ia （QN-Ia）. The spin-down energy injected by the Quark-Nova remnant （the quark star） contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape. We demonstrate that the parameters describing QN-Ia are NOT constant in redshift. Simulated QN-Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters. We determine a correction between the true and fitted distance moduli, which when applied to Type-Ia SNe in the Hubble diagram recovers the ΩM = 1 cosmology. We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe （if the observed SNe Ia are dominated by QNe Ia） and by association the need for dark energy.

关键词： dark energy -- cosmology observations -- supernovae general

Metamorphosis of Magnetospirillum magneticum AMB-1 cells

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Chinese Journal of Oceanology and Limnology 2010年第2期28卷 304-309页

作者：张风丽张葵赵三军肖天 Michel denis 吴龙飞 Laboratoire de Chimie Bactérienne UPR9043 Institut de Biologie Structurale et Microbiologie Laboratory of Marine Biotechnology School of Life Sciences & Biotechnology Key Laboratory of Microbial Metabolism Ministry of Education Shanghai Jiao Tong University Laboratoire de Microscopies et d’Etude de Nanostructures (LMEN) Université de Reims Key Laboratory of Marine Ecology & Environmental Sciences Institute of Oceanology Chinese Academy of Sciences Laboratoire de Microbiologie Géochimie et Ecologie Marines CNRS UMR6117 Centre d'Océanologie de Marseille Université de la Méditerranée

Magnetospirillum magneticum strain AMB-1 belongs to the family of magnetotactic bacteria. It possesses a magnetosome chain aligning, with the assistance of cytoskeleton filaments MamK, along the long axis of the spiral cells. Most fresh M. magneticum AMB-1 cells exhibit spiral morphology. In addition, other cell shapes such as curved and spherical were also observed in this organism. Interestingly, the spherical cell shape increased steadily with prolonged incubation time. As the actin-like cytoskeleton protein MreB is involved in maintenance of cell shapes in rod-shaped bacteria such as Escherichia coli and Bacillus subtilis, the correlation between MreB protein levels and cell shape was investigated in this study. Immunoblotting analysis showed that the quantity of MreB decreased when the cell shape changed along with incubation time. As an internal control, the quantity of MamA was not obviously changed under the same conditions. Cell shape directs cell-wall synthesis during growth and division. MreB is required for maintaining the cell shape. Thus, MreB might play an essential role in maintaining the spiral shape of M. magneticum AMB-1 cells.

关键词： Magnetotactic bacteria Magnetospirillum magneticum AMB-1 MreB

Exploratory study on bitumen content determination for foamed bitumen mixes based on porosity and indirect tensile strength

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Journal of Traffic and Transportation Engineering(English Edition) 2017年第2期4卷 131-144页

作者： May Namutebi Bjorn Birgisson Alvaro Guarin denis Jelagin Division of Highway and Railway Engineering KTH Royal Institute of Technology Stockholm Sweden Department of Civil and Environmental Engineering Makerere University Kampala Uganda

Optimum bitumen content determination is one of the major aims for foamed bitumen mix design. However, mix design procedures for foamed bitumen mixes are still under development. In this paper a method to determine the optimum bitumen content for given foamed bitumen mix based on primary aggregate structure porosity and indirect tensile strength criterion is proposed. Using packing theory concepts, the aggregate gradation is divided into three aggregate structures which are oversize, primary and secondary struc- tures. Porosity for the primary aggregate structure is determined for given bitumen contents. A maximum value for porosity of 50% for the primary aggregate structure is used to choose initial bitumen content. Furthermore, a minimum indirect tensile strength criteria is suggested to refine this bitumen content. This method enables a bitumen content value to be chosen prior to the start of experimental work, as porosity is expressed in terms of physical parameters such as aggregate and binder specific gravity, and aggregate gradation which are known before the mix design process. The bitumen content is then later refined when the indirect tensile strength is determined in the laboratory. This method would reduce resources such as time and materials that may be required during the mix design procedure.

关键词： Foamed bitumen Bitumen content Aggregate Porosity Gradation framework Indirect tensile strength

On the correctness of orbital solutions obtained from a small set of *** of HIP 53731

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Research in Astronomy and Astrophysics 2020年第11期20卷 321-324页

作者： Arina Mitrofanova Vladimir Dyachenko Anatoly Beskakotov Yury Balega Alexander Maksimov denis Rastegaev Sergey Komarinsky Special Astrophysical Observatory of the Russian Academy of Sciences Nizhnij ArkhyzRussia 369167

HIP 53731 is a binary consisting of stars of the spectral types K0 and *** orbit of this object was constructed previously by Cvetkovic et *** improved by *** should be noted that there is a 180°ambiguity in the position angles of some published *** interferometric observations were obtained in 2007–2020(21 measurements)at the 6-m telescope of the SAO RAS(BTA)by the authors of this *** analysis of new data together with previously published ones made it possible to construct an accurate orbit of HIP 53731 and to halve the already known values of the orbital period of the *** a result of the study,the mass sum,the masses of each component and their spectral types were determined by two independent *** to the qualitative classification of orbits,the orbital solution has grade 2–"good"(observations cover more than half of the orbital period and correspond to different phases).

关键词： techniques high angular resolution,speckle interferometry stars low-mass,fundamental parameters stars binaries spectroscopic stars individual HIP 53731