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Prediction of interphase drag coefficient and bed expansion using a variational model for fluidization of small spherical particles

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Particuology 2020年第4期18卷 184-192页

作者： Mihal Duris Zorana Arsenijevic Radmila Garic-Grulovic Tatjana Kaluderovic Radoicic Institute of Chemistry Technology and Metallurgy(National Institute)Department for Catalysis and Chemical EngineeringUniversity of BelgradeNjegoseva 12BelgradeSerbia Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 4BelgradeSerbia

In this study,we applied the variational model to fluidization of small spherical *** experiments were carried out for spherical particles with 13 diameters between dp=0.13 and 5.00 *** propose a generalized form of our variational model to predict the superficial velocity U and interphase drag coefficientβby introducing an exponent n to describe the different dependences of the drag force Fd on fluid velocity for different particle sizes(different flow regimes).By comparing the predictions with the experimental results,we conclude that n=1 should be used for small particles(dp1 mm).This conclusion is generalized by proposing n=1 for particles with Ret*** average mean absolute error was 5.49%in calculating superficial velocity for different bed voidages using the modified variational model for all of the particles *** calculated values ofβwere compared with values of literature models for particles with dp<1.0 *** average mean absolute error of the modified variational model was 8.02%in calculatingβfor different bed voidages for all of the particles examined.

关键词： Calculus of variations Isoperimetric problem Bed expansion Drag coefficient Fluidization Spherical particles

Assessing Criteria Weights by the Symmetry Point of Criterion (Novel SPC Method)–Application in the Efficiency Evaluation of the Mineral Deposit Multi-Criteria Partitioning Algorithm

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Computer Modeling in Engineering & Sciences 2023年第7期136卷 955-979页

作者： Zoran Gligoric Milos Gligoric Igor Miljanovic Suzana Lutovac Aleksandar Milutinovic Faculty of Mining and Geology University of BelgradeBelgrade11000Serbia

Information about the relative importance of each criterion or theweights of criteria can have a significant influence on the ultimate rank of ***,assessing the weights of criteria is a very important task in solving multi-criteria decision-making *** methods are commonly used for assessing the weights of criteria:objective,subjective,and integrated *** this study,an objective approach is proposed to assess the weights of criteria,called SPCmethod(Symmetry Point of Criterion).This point enriches the criterion so that it is balanced and easy to implement in the process of the evaluation of its influence on *** SPC methodology is systematically presented and supported by detailed calculations related to an artificial *** validate the developed method,we used our numerical example and calculated the weights of criteria by CRITIC,Entropy,Standard Deviation and MEREC *** analysis between these methods and the SPC method reveals that the developedmethod is a very reliable objective way to determine the weights of ***,in this study,we proposed the application of SPCmethod to evaluate the efficiency of themulti-criteria partitioning *** main idea of the evaluation is based on the following fact:the greater the uniformity of the weights of criteria,the higher the efficiency of the partitioning *** research demonstrates that the SPC method can be applied to solving different multi-criteria problems.

关键词： Multi-criteria decision-making weights of criteria symmetry point of criterion mineral deposit partitioning algorithm performance evaluation

Simulation-based correction of dose enhancement factor values in photon brachytherapy with metal nanoparticle targeting

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Nuclear Science and Techniques 2020年第11期31卷 93-106页

作者： Slobodan Milutinovic Milos Vujisic School of Electrical Engineering University of BelgradeBelgradeSerbia Vinca Institute of Nuclear Sciences-National Institute of tht Republic of Serbia University of BelgradeBelgradeSerbia

The purpose of this study is to investigate and quantify the influence of nanoparticle composition,size,and concentration on the difference between dose enhancement values derived from Monte Carlo simulations with homogeneous and structured geometrical representations of the target region in metal nanoparticle-enhanced photon *** of the dose enhancement factor(DEF)were calculated for Pd-103,I-125,and Cs-131 brachytherapy sources with gold,silver,or platinum nanoparticles acting as targeting *** were performed using the Geant4 toolkit with condensed history models of electron *** limits were imposed on adjustable parameters that define secondary electron histories,so that simulations came closest to true event-byevent electron tracking,thereby allowing part of the nanoparticle-laden volume used for calculating the dose to be represented as a structured region with uniformly distributed discrete ***-tuned physical models of secondary radiation emission and propagation,along with the discrete geometrical representation of nanoparticles,result in a more realistic assessment of dose *** DEF correction coefficient is introduced as a metric that quantifies the absorption of secondary radiation inside the nanoparticles themselves,a phenomenon disregarded when the target region is treated as a homogeneous metal–tissue mixture,but accounted for by discrete nanoparticle *** approach applied to correcting DEF values both draws from and expands upon several related investigations published *** of the obtained results to those found in relevant references shows both agreement and deviation,depending on nanoparticle properties and photon energy.

关键词： Monte Carlo Brachytherapy Nanoparticles Dose enhancement Geant4

Immune defense of wild-caught Norway rats is characterized by increased levels of basal activity but reduced capability to respond to further immune stimulation

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Integrative Zoology 2018年第2期13卷 180-193页

作者： Ivana MIRKOV Aleksandra POPOV ALEKSANDROV Vesna SUBOTA Dragan KATARANOVSKI Milena KATARANOVSKI Immunotoxicology Group Department of EcologyInstitute for Biological Research“Sinisa Stankovic”University of BelgradeBelgradeSerbia Institute for Medical Biochemistry Military Medical AcademyBelgradeSerbia Institute of Zoology Faculty of BiologyUniversity of BelgradeBelgradeSerbia Institute of Physiology and Biochemistry Faculty of BiologyUniversity of BelgradeBelgradeSerbia

Studies of wild animals’immunity often use comparison with laboratory-raised *** such an approach,various data were obtained concerning wild Norway rat’s *** or higher potential of immune system cells to respond to activation stimuli were shown,because of analysis of disparate parameters and/or small number of analyzed *** differences between laboratory and wild rats were shown too,owing to great response variability in wild *** hypothesized that wild rats will express more intense immune activity compared to their laboratory counterparts which live in a less demanding *** test this,we analyzed the circulating levels of inflammatory cytokine interleukin-6(IL-6),a mediator which has a central role in host immune *** addition,we examined the activity of the central immune organ,the spleen,including cell proliferation and production of pro-inflammatory cytokines interferon-γ(IFN-γ)and interleukin-17(IL-17),which are major effectors of cellular adaptive immune *** order to obtain reasonable insight into the immunity of wild Norway rats,analysis was conducted on a much larger number of individuals compared to other *** levels of plasma IL-6,higher spleen mass,cellularity and basal IFN-γproduction concomitantly with lower basal production of anti-inflammatory cytokine interleukin-10(IL-10)revealed more intense immune activity in the wild compared to laboratory ***,lower responsiveness of their spleen cells’proinflammatory cytokine production to concanavalin A(ConA)stimulation,along with preserved capacity of IL-10 response,might be perceived as an indication of wild rats’reduced capability to cope with incoming environmental stimuli,but also as a means to limit tissue damage.

关键词： circulating interleukin-6 levels spleen cell cytokine production spleen cell proliferation

Interplay of SOX transcription factors and microRNAs in the brain under physiological and pathological conditions

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Neural Regeneration Research 2022年第11期17卷 2325-2334页

作者： Milena Stevanovic Danijela Stanisavljevic Ninkovic Marija Mojsin Danijela Drakulic Marija Schwirtlich Laboratory for Human Molecular Genetics Institute of Molecular Genetics and Genetic EngineeringUniversity of BelgradeBelgradeSerbia university of belgrade Faculty of BiologyBelgradeSerbia Serbian Academy of Sciences and Arts BelgradeSerbia

Precise tuning of gene expression,accomplished by regulato ry networks of transcription factors,epigenetic modifiers,and microRNAs,is crucial for the proper neural development and function of the brain *** SOX transcription factors are involved in regulating diverse cellular processes during embryonic and adult neurogenesis,such as maintaining the cell stemness,cell prolife ration,cell fate decisions,and terminal diffe rentiation into neurons and glial *** represent a class of small non-coding RNAs that play important roles in the regulation of gene *** with other gene regulatory factors,microRNAs regulate different processes during neurogenesis and orchestrate the spatial and temporal expression important for *** emerging data point to a complex regulatory network between SOX transcription factors and microRNAs that govern distinct cellular activities in the developing and adult *** SOX/mic roRNA interplay in signaling pathways that influence the homeostasis and plasticity in the brain has been revealed in various brain pathologies,including neurodegenerative disorders,traumatic brain injury,and *** strategies that target SOX/microRNA interplay have emerged in recent years as a promising tool to target neural tissue regeneration and enhance neuro restoration.N umerous studies have confirmed complex intera ctions between microRNAs and SOX-specific mRNAs regulating key features of *** in mind the crucial roles of SOX genes and microRNAs in neural development,we focus this review on SOX/microRNAs interplay in the brain during development and adulthood in physiological and pathological *** focus was made on their interplay in brain pathologies to summarize current knowledge and highlight potential future development of molecular therapies.

关键词： dysregulation of miRNA expression glioblastoma gliogenesis glioma stem cells ischemic stroke neural stem cells neural tissue regeneration neurodegenerative diseases neurodevelopment neurogenesis SOX/miRNA interplay traumatic brain injury

Surface modifications of biometallic commercially pure Ti and Ti–13Nb–13Zr alloy by picosecond Nd:YAG laser

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 285-295页

作者： Slađana Laketić Marko Rakin MilošMomčilović Jovan Ciganović Đorđe Veljović Ivana Cvijović-Alagić Vinča Institute of Nuclear Sciences University of BelgradeP.O.Box 52211001 BelgradeSerbia Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia

The effects of picosecond Nd:YAG laser irradiation on chemical and morphological surface characteristics of the commercially pure titanium and Ti–13Nb–13Zr alloy in air and argon atmospheres were studied under different laser output energy *** the interaction of laser irradiation with the investigated materials,a part of the energy was absorbed on the target surface,influencing surface *** beam interaction with the target surface resulted in various morphological alterations,resulting in crater formation and the presence of microcracks and hydrodynamic ***,different chemical changes were induced on the target materials’surfaces,resulting in the titanium oxide formation in the irradiation-affected area and consequently increasing the irradiation energy *** the high energy absorption at the site of interaction,the dimensions of the surface damaged area ***,surface roughness *** appearance of surface oxides also led to the increased material hardness in the surface-modified *** chemical and morphological changes were pronounced after laser irradiation of the Ti–13Nb–13Zr alloy surface.

关键词： commercially pure titanium Ti-13Nb-13Zr alloy surface modification Nd:YAG laser laser-induced damage hard oxidized surface

Penile prosthesis implantation and tunica albuginea incision without grafting in the treatment of Peyronie＇s disease with erectile dysfunction

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Asian Journal of Andrology 2013年第3期15卷 391-394页

作者： Miroslav L Djordjevic Vladimir Kojovic School of Medicine University of Belgrade Belgrade 11000 Serbia

We evaluated penile prosthesis implantation with tunica albuginea-relaxing incisions without grafting in the treatment of Peyronie＇s disease associated with erectile dysfunction. Between April 2005 and June 2011, 62 patients underwent surgery due to severe Peyronie＇s disease associated with erectile dysfunction. Malleable and inflatable penile prostheses were inserted in 49 and 13 cases, respectively. Penile prostheses were inserted into the corpora cavernosa using the standard ventral approach. After lifting the neurovascular bundle, the tunica albuginea was incised and opened at the plaque region to correct the deformities and to lengthen the penis. Subsequently, the wide neurovascular bundle was replaced, and all incisions of the tunica albuginea were covered to prevent corporal grafting. In the median follow-up of 35 months （range 14-82 months）, the penis was completely straightened in 59 （95%） patients. Numbness of the glans, which the patients found initially upsetting, decreased or disappeared spontaneously 3-6 months later. Penile prosthesis implantation with tunica albuginea incisions is a viable alternative in the treatment of Peyronie＇s disease because the extensive dissection of the neurovascular bundle allows a good approach to the plaque and provides excellent covering of the incised tunica albuginea without additional grafting.

关键词： erectile dysfunction neurovascular bundle penile prosthesis Peyronie's disease tunica albuginea

Emergency Management in Critical Infrastructures: A Complex-Event-Processing Paradigm

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Journal of Systems Science and Systems Engineering 2019年第1期28卷 37-62页

作者： Vuk Mijovic Nikola Tomasevic Valentina Janev Mladen Stanojevic Sanja Vranes The Mihajlo Pupin Institute University of Belgrade Volgina 1511060 Belgrade Serbia

Critical infrastructures (CI) are difficult to handle due to their complexity, size and the number of stakeholders involved. During emergency situations (e.g. fire or terrorist attack), a CI operator in the control room is faced with a flood of information coming from different sensors and legacy monitoring systems. Since in these situations, time is critical and the operators are under a great deal of pressure, a holistic management of all the technical systems and actors involved is needed, reinforced by the Recommendation and Decision Support System (RDSS) that helps emergency managers to take correct and timely decisions. One way to provide an adequate RDSS support to the operator is proposed in this paper which is based on an intelligent, event driven layer that sits on top of the legacy CI monitoring system. Powered by the complex event processing capabilities and facility data model implemented in the form of CI ontology, this layer processes events originating from different sources, conducts the situation and risk assessment, and reacts accordingly, either automatically or via recommendations proposed to emergency personnel. To validate the proposed approach, an event-driven RDSS was deployed on an airport use case (Nikola Tesla airport in belgrade), as one of the most complex CIs.

关键词： Emergency management event-driven decision support complex event processing emergency personnel training

Evaluation of stability and functionality of BaCe_(1−x)In_(x)O_(3−δ) electrolyte in a wider range of indium concentration

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Journal of Advanced Ceramics 2022年第3期11卷 443-453页

作者： Aleksandar MALESEVIC Aleksandar RADOJKOVIC Milan ZUNIC Aleksandra DAPCEVIC Sanja PERAC Zorica BRANKOVIC Goran BRANKOVIC Center of Excellence for Green Technologies Institute for Multidisciplinary ResearchUniversity of BelgradeKneza Viseslava 711030 BelgradeSerbia Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia

The properties of BaCe_(1−x)In_(x)O_(3−δ) (x = 0.05, 0.10, 0.15, 0.20, _(0.25), 0.30, 0.35, and 0.40) as proton conducting electrolyte are examined. The dense electrolyte is formed after sintering at 1300 ℃ for 5 h in air. The samples with In content ≥ 25 mol% contain In_(2)O_(3) as a secondary phase. The highest total conductivity is around 5×10^(−3) S/cm for BaCe_(0.75)In_(0.25)O_(3−δ) in the wet hydrogen atmosphere at 700 ℃. After exposure to pure CO_(2) atmosphere at 700 ℃ for 5 h, the concentrations of at least 15 mol% In can completely suppress degradation of the electrolyte. The power density of Ni-BaCe_(0.75)In_(0.25)O_(3−δ)/BaCe_(0.75)In_(0.25)O_(3−δ)/LSCF-BaCe_(0.75)In_(0.25)O_(3−δ) fuel cell tested in wet hydrogen atmosphere reaches 264 mW/cm2 at 700 ℃. This result is an indication of stability and functionality of this electrolyte and its versatility in respect to type of fuel and performing environment.

关键词： ionic conductivity perovskite fuel cell BaCeO_(3)