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Number of results: 72
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Abstract

Fourteen symposia on early/lower vertebrates have taken place over the last 50 years, usually at about four year

intervals. An average 60 participants have taken part at these symposia, with over one hundred occasionally. The

results of the symposia have been published in proceedings. The symposia started honoring E. A:son Stensiö and

E. Jarvik. Honors were taken up at the 11th symposium in Uppsala again. Since the 13th symposium a Stensiö

award is also given to young researchers in the field.

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Authors and Affiliations

Hans-Peter Schultze
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Abstract

This paper proposes a microfounded model featuring frictional labor markets that generates procyclical R&D expenditures as a result of optimizing behavior by heterogeneous monopolistically competitive firms. This allows to show that business cycle fluctuations affect the aggregate endogenous growth rate of the economy. Consequently, transitory shocks leave lasting level effects. This mechanism is responsible for economically significant hysteresis effects that significantly increase the welfare cost of business cycles relative to the exogenous growth model. I show that this has serious policy implications and creates ample space for policy intervention. I find that several static and countercyclical subsidy schemes are welfare improving. Importantly, I find that due to labor market frictions subsidizing incumbent firms generates large and positive welfare effects.
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Authors and Affiliations

Marcin Bielecki
1

  1. University of Warsaw, Poland, Narodowy Bank Polski
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Abstract

The present article attempts to discuss whether a medical conference poster intended for a specific English-speaking discourse community shares the properties of discourse colony (Hoey 1986). The author analyses 12 e-posters, which were displayed during an international neurological conference, presenting findings on epilepsy treatment. First, the author characterises the conference poster, which is followed by a description of discourse community and discourse colony. Next, the analysis of the e-posters is carried out and the results of the analysis are presented. On the basis of these results it might be said that the medical conference poster could be considered a discourse colony as it shares some of its properties.

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Authors and Affiliations

Jacek Pradela
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Abstract

The aim of any industrial plant, which is dealing in the energy sector, is to maximise the revenue generation at the lowest production cost. It can be carried out either by optimizing the manpower or by improving the performance index of the overall unit. This paper focuses on the optimisation of a biomass power plant which is powered by G50 hardwood chips (Austrian standard for biomass chips). The experiments are conducted at different operating conditions. The overall effect of the enhanced abilities of a reactor on the power generation is examined. The output enthalpy of a generated gas, the gas yield of a reactor and the driving mechanism of the pyrolysis are examined in this analysis. The thermal efficiency of the plant is found to vary from 44 to 47% at 400◦C, whereas it is 44 to 48% for running the same unit at 600 ◦C. The transient thermal condition is solved with the help of the lumped capacitance method. The thermal efficiency of the same design, within the constraint limit, is enhanced by 5.5%, whereas the enthalpy of the produced gas is magnified by 49.49% through nonlinear optimisation. The temperature of biomass should be homogenous, and the ramping rate must be very high. The 16% rise in temperature of the reactor is required to reduce the mass yield by 20.17%. The gas yield of the reactor is increased by up to 85%. The thermal assessment indicates that the bed is thermally thin, thus the exterior heat transfer rate is a deciding factor of the pyrolysis in the reactor.

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Authors and Affiliations

Alok Dhaundiyal
Suraj B. Singh
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Abstract

Acoustic signal is more and more frequently used to diagnose machines operated in industrial conditions where installation of sensors is hindered. Impact of background noise seems to be the major problem as part of analysis of such signal. In most cases of industrial environments, background level is high; thus, it prevents against concluding as per standard methods that have been used in diagnostic testing. This study specifies the problem related to diagnosing machines operated under variable loads. Synchronous methods are used for diagnosing these types of machines, those include synchronisation of diagnostic signal with revolutions of the diagnosed machine. For the purpose of this study an acoustic signal was used as the diagnostic signal. Application of the synchronous method (order analysis) enables eliminating an impact of background noise derived from other sources. This study specifies application of acoustic signal to diagnose planetary gear in laboratory testing rig in order to discover damages at early stage of degradation. This method was compared with the method basing on measurement of vibrations.

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Authors and Affiliations

Paweł Pawlik
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Abstract

Coexisting microorganisms are abundant in nature. Plant growth promoting rhizobacteria (PGPR) is a group of beneficial microorganism living around the roots of plants which are able to confer beneficial effects on plant growth. Streptomyces sp. is a gram-positive bacteria as PGPR that can promote plant growth and enhance tolerance in adverse environment. This research was aimed to study the effects of plant growth promotion and stress tolerance of Streptomyces sp. in Arabidopsis and Brassica sp. The amount of indole-acetic acid (IAA) and phosphate solubility were assessed from isolated bacterial. Plant growth promotion was examined in 10-days old seedling with three independent experiments. Our results showed that Streptomyces sp. produced moderate levels of IAA and it was able to solubilize phosphate. Inoculation of Streptomyces sp. enhanced lateral root number, fresh weight and chlorophyll content in Arabidopsis thaliana. Moreover, the inoculation of Streptomyces sp. significantly increased vegetative growth on Arabidopsis and Brassica sp. by producing higher fresh weight and chlorophyll content. Streptomyces sp. also enhanced tolerance to abiotic stress in Arabidopsis and Brassica sp. by increasing fresh weight under condition of salt and heat stress. Under salt stress, inoculation of Streptomyces sp. in Arabidopsis induced activity of catalase enzyme and decreased hydrogen peroxide (H2O2) and malondialdehyde (MDA) production. In the molecular levels, Streptomyces sp. induced protein accumulations in Arabidopsis including nitrogen assimilation (GS1), carbohydrate metabolism (cFBPase), and the light-harvesting chlorophyll (Lhcb1) protein.

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Authors and Affiliations

Windy Manullang
Huey-wen Chuang
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Abstract

An application of biostimulants is becoming an increasingly popular operation in agriculture because they positively affect crop performance and qualitative characteristics, and prevent stress-related losses. The objective of this study was to determine the effect of an application of the following biostimulants: PlonoStart, Aminoplant, and Agro-Sorb Folium, and the herbicide Avatar 293 ZC on total carotenoids in table potato tubers. The research material consisted of tubers of two table potato cultivars, Oberon and Malaga, which were produced in a 3-year field experiment. Chemical analyses of fresh material were conducted 4–6 days following harvest. Biostimulants applied with the herbicide significantly increased the table potato tuber content of carotenoids compared to tubers obtained from unamended control plots. The highest accumulation of carotenoids was determined following an application of the biostimulant Agro-Sorb Folium, and it was higher in the tubers of cv. Oberon versus cv. Malaga. It should be added that in the available literature there is no research on the effect of biostimulants on the content of carotenoids in potato, which is the main food in the world. Carotenoids perform many important functions in the human body. They exhibit antioxidant properties, which means that they protect cells from damage, and also have a beneficial effect on the immune system. Carotenoids are substances that show an indispensable effect on the health and appearance of the skin. Regular consumption of them in the form of vegetables and fruits ensures its firmness, elasticity, smoothness, as well as a healthy appearance. The protective function of carotenoids against free radicals simultaneously contributes to slowing down the aging process. This action, in turn, translates into preventing the development of cancer or diseases of the circulatory system.
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Authors and Affiliations

Iwona Mystkowska
1
ORCID: ORCID
Krystyna Zarzecka
2
ORCID: ORCID
Marek Gugała
2
ORCID: ORCID
Agnieszka Ginter
2
ORCID: ORCID

  1. Department of Dieteties, John Paul II University of Applied Sciences, Biała Podlaska, Poland
  2. Department of Agrobioengineering and Animal Sciences, Institute of Agriculture and Horticulture, Siedlce University of Natural Sciences and Humanities, Siedlce, Poland
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Abstract

High voltage direct current (HVDC) emergency control can significantly improve the transient stability of an AC/DC interconnected power grid, and is an important measure to reduce the amount of generator and load shedding when the system fails. For the AC/DC interconnected power grid, according to the location of failure, disturbances can be classified into two categories: 1) interconnected system tie-line faults, which will cause the power unbalance at both ends of the AC system, as a result of the generator rotor acceleration at the sending-end grid and the generator rotor deceleration at the receiving-end grid; 2) AC system internal faults, due to the isolation effect of the DC system, only the rotor of the generator in the disturbed area changes, which has little impact on the other end of the grid. In view of the above two different locations of disturbance, auxiliary power and frequency combination control as well as a switch strategy, are proposed in this paper. A four-machine two-area transmission system and a multi-machine AC/DC parallel transmission system were built on the PSCAD platform. The simulation results verify the effectiveness of the proposed control strategy.

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Authors and Affiliations

Congshan Li
ORCID: ORCID
Ping He
ORCID: ORCID
Youyi Wang
Yuyi Ji
Cunxiang Yang
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Abstract

This paper proposes two high-order sliding mode algorithms to achieve highperformance control of induction motor drive. In the first approach, the super-twisting algorithm (STA) is used to reduce the chattering effect and to improve control accuracy. The second approach combines the super-twisting algorithm with a quasi-barrier function technique. While the super-twisting algorithm (STA) aims at the chattering reduction, the Barrier super-twisting algorithm (BSTA) aims to eliminate this phenomenon by providing continuous output control signals. The BSTA is designed to prevent the STA gain from being over-estimated by making these gains to decrease and increase according to system’s uncertainties. Stability and finite-time convergence are guaranteed using Lyapunov’s theory. In addition, the two controlled variables, rotor speed, and rotor flux modulus are estimated based on the second-order sliding mode (SOSM) observer. Finally, simulations are carried out to compare the performance and robustness of two control algorithms without adding the equivalent control. Tests are achieved under external load torque, varying reference speed, and parameter variations.
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Authors and Affiliations

Salah Eddine Farhi
1
Djamel Sakri
1
Noureddine Golèa
1

  1. Laboratory of Electrical Engineering and Automatic, LGEA, Larbi Ben M’hidi University, Oum El Bouaghi, Algeria
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Abstract

Finger vein biometric systems become increasingly more popular because they offer higher security comparing to other authentication solutions with respect to positive persons experience. Those systems operate on near infrared light (NIR) in wavelength range from around 700 to 1000 nm, however dedicated research to determine impact of NIR lighting on biometric system effectiveness has not been conducted and presented in the literature ever before. In this paper the study of correlation between wavelengths in NIR spectra and effectiveness of person identification in a biometric system is presented. To achieve that goal, a new model of image acquisition system allowing change of light wavelengths has been created and NIR finger vein dataset containing 11 556 images was established. Furthermore, this model was used to perform experimental work and proof that some NIR wavelengths better suit for vein patterns acquisition, allowing to increase the recognition effectiveness of finger vein biometric systems.

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Authors and Affiliations

M. Waluś
K. Bernacki
J. Konopacki
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Abstract

The paper presents a method of measuring deformations of cylindrical samples on the testing machine for free tube hydroforming experiments. During experiments a sample made of a thin-walled metal tube is expanded by the internal pressure of the working liquid and additionally subjected to axial compression. This results in a considerable circumferential deformation of the tube and its shortening. Analysis of the load cases and their impact on the deformations can be helpful in determining e.g. tube material properties or general limiting conditions in the tube hydroforming process. In connection with the above, the value of deformations and knowledge of their course during experiment has become one of the most important problems related to the issue described above.

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Authors and Affiliations

H. Sadłowska
Ł. Morawiński
C. Jasiński
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Abstract

Most antiseptic agents are intended for use on intact skin, e.g. for hand hygiene or skin preparation before any medical procedure. This paper presents multiple emulsion-based antiseptic agents as formulations for application to body surfaces with modified release rates.
Multiple emulsions with a co-encapsulated antiseptic (phenyl salicylate – salol) and an agent preventing microorganism growth (benzoic acid) were formed in a Couette–Taylor flow apparatus. Results confirmed the possibility of the release kinetics modification while two compounds were encapsulated in the internal droplets of emulsions to control the release rates and time of the dose release. The addition of benzoic acid as a second active compound of the encapsulation process in the internal phase of double O1/W/O2 emulsion reduced the time necessary for the total release of salol triggering a two-step release.
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Authors and Affiliations

Agnieszka Markowska-Radomska
1
ORCID: ORCID
Ewa Dluska
1
ORCID: ORCID
Agata Metera
1
Maria Wojcieszak
1

  1. Warsaw University of Technology, Faculty of Chemical and Process Engineering, Warynskiego 1, 00-645 Warsaw, Poland
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Abstract

In this paper both envelope approach and morphological filters for characterisation of surface textures were proposed, applied and thoroughly examined. Obtained results were compared with those received after appliance of commonly-used algorithms. The effect of appliance of proposed procedures on surface topography parameters (from ISO 25178 standard) was taken into consideration. The following types of surface textureswere assessed: two-process plateau-honed cylinder liners, plateau-honed cylinder liners with additionally burnished dimples, turned piston skirts, grinded and/or isotropic topographies. It was assumed that envelope characteristics (envelope filtration) can provide results useful for assessments of deep and/or wide oil-reservoirs especially when they are edge located. Moreover, some near-valley areas of surface texture details can be less distorted when envelope filtering is accomplished. It was also found that closing and/or opening envelope filtration can be valuable for reduction of some surface topography measurement errors.

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Authors and Affiliations

Przemysław Podulka
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Abstract

Yeast infections such as otitis externa and seborrheic dermatitis in dogs and cats are frequently associated with Malassezia pachydermatis secondary infection. It is part of the normal cutaneous microflora of most warm-blooded vertebrates, however, under certain conditions, it can become a causative agent of infection that needs to be treated pharmacologically. Azole derivatives are the drugs of the first choice. An interesting trend in developing resistance is the use of natural substances, which include manuka honey with confirmed antimicrobial properties. The main intention of this research was to evaluate the mutual effect of manuka honey in combination with four conventional azole antifungals – clotrimazole, fluconazole, itraconazole, and miconazole – on 14 Malassezia pachydermatis isolates obtained from dogs and 1 reference strain. A slightly modified M27–A3 method (CLSI 2008) and the checkerboard test (Nikolić et al. 2017) were used for this purpose. Our results show an additive effect of all 4 antifungals with manuka honey concurrent use. Based on the determined values of fractional inhibitory concentration index (FICI – 0.74±0.03 when manuka honey combined with clotrimazole, 0.96±0.08 with fluconazole, 1.0±0 with miconazole and 1.16±0.26 with itraconazole), it was found in all cases that the effect of substances used is more pronounced in mutual combination than when used separately.
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Authors and Affiliations

P. Váczi
1
E. Čonková
1
Z. Malinovská
1

  1. Department of Pharmacology and Toxicology, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Košice, Slovakia
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Abstract

The present study was undertaken to highlight the influence of simvastatin administration on hepatocyte morphology, proliferation, and apoptosis. The study included 48 gilts aged 3 months (weighing ca. 30 kg) divided into groups I (control; n=24) and II, receiving 40 mg/animal simvas- tatin orally (simavastatin; n=24) for 29 days. The animals were euthanized on days subsequent to the experiment. The livers were sampled, fixed, and processed routinely for histopathology, histochemistry, and immunohistochemistry (for proliferating cell nuclear antigen, Bcl-2, and caspase-3). Apoptosis was visualized by terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL). Simvastatin administration caused acute hepatocyte swelling, glycogen de- pletion, hyperaemia, multifocal hepatocyte proliferation with occasional pseudoacinar formation, connective tissue hyperplasia, eosinophil infiltration, and interface hepatitis. The proliferating cell nuclear antigen index, mean diameter of argyrophilic nucleolar organizer regions, and Bcl-2 immunoexpression were lower compared to control, and mean caspase-3 immunoexpression was higher in group II compared to control. On day 25 and 29 single hepatocytes in the simvasta- tin-treated group were TUNEL-positive. Simvastatin caused morphological alteration which became more intense over time. The results from the present study suggest that simvastatin treat- ment may cause glycogen, lipid metabolism and cell membrane permeability distortion, fibrosis, interface hepatitis, reduction in hepatocyte proliferation and transcriptional activity, and enhanced vulnerability to apoptosis. Summing up the results, it can be concluded that simvastatin caused liver damage with similar morphological changes seen in autoimmune-like liver injury, which may indicate that simvastatin may induce autoimmune-like drug induced liver injury.

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Authors and Affiliations

M. Mikiewicz
I. Otrocka-Domagała
K. Paździor-Czapula
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Abstract

This article proposes an analytical model of a system with priorities servicing a mixture of different elastic traffic streams. The model presented in the article was developed as the extension of earlier works published by the authors. It utilizes the concept of equivalent bandwidth and then, following bandwidth discretization, uses the dependencies introduced on the basis of the assumptions adopted for the generalized Kaufman-Roberts formula and for the model of a full-availability group with traffic compression. The article presents a possibility of using the proposed model to model the radio interface in a multi-service mobile network and provides an example of the above with the interface of an LTE network. Since the proposed model is an approximate one, the results of the calculations are compared with the results of simulations. A comparison of the results confirms an acceptable level of accuracy of the model. The model can be successfully used in the analysis and design of links and nodes of telecommunication and computer networks.

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Authors and Affiliations

B. Nowak
ORCID: ORCID
M. Piechowiak
M. Stasiak
P. Zwierzykowski

Authors and Affiliations

Jan Dzierżek
1
Robert Janiszewski
1

  1. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warszawa, Poland
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Abstract

Construction and demolition (C&D) waste management should be accordance with the waste management hierarchy. In practice, C&D waste are often downcycling. It is the result of many factors, including lack of awareness about the value inherent in waste. The paper presents analysis of the adaptability of non-destructive testing (NDT) methods for technical assessment of waste properties. As part of the work, non-destructive testing methods were described and classified in accordance with material and the features they enable testing. The publication presents examples of the use of NDT in the recovery of building materials during construction projects, in the field of influence of technical information of waste on the way it is managed. Finally, a scheme of waste management process during the renovation of an object with the application of NDT methods was presented.

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Authors and Affiliations

J. Jaskowska-Lemańska
J. Sagan
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Abstract

The paper presents the results of testing the bearing resistance of the bolted joints of thin-walled profiles used in modular construction. The two types of joints currently applied in the construction industry were subjected to tests. One of them served as the reference sample, and the other as the research sample, which was used to find a solution that is more favorable in terms of the complexity of its production process and its bearing resistance. In addition to the modified shape of the end-plates, the bearing resistance of the joint was also analyzed with regards to the different diameters of bolts (bolts M12 and M16 were used), their classes (the difference between bolts of class 8.8 and 10.9 was examined), and also the number of them in the joint (3 or 5 bolts). Moreover, two thicknesses of steel sheets (3 mm and 4 mm), from which thin-walled cold-bent profiles were made, were used in the research. The bearing resistance tests were carried out with the use of a testing press of the authors’ own design. On the basis of the measurements, plots of the dependence between the deflection of the samples and the force acting in the middle of their span were drawn. It was shown that the tested profile joint had an increased bearing resistance by up to 26% when compared to the reference sample. The maximum destructive bending moment M was equal to 10.7 kN·m for the reference sample, and to 13.5 kN·m for the analyzed design solution. In total, 6 types of modified joints were made for the tests, of which five showed a comparable or higher bearing resistance than the reference sample. Each type of joint was tested by bending it in two directions in relation to the central axis of its cross-section.
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Authors and Affiliations

Karol Prałat
1
ORCID: ORCID
Arkadiusz Plis
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Mechanics and Petrochemistry, Łukasiewicza 17, 09-400 Płock, Poland
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Abstract

In this paper, existing knowledge on the behaviour of soil-steel composite structures (SSCSs) has been reviewed. In particular, the response of buried corrugated steel plates (CSPs) to static, semistatic, and dynamic loads has been covered. Furthermore, the performance of SSCS under extreme loading, i.e., loading until failure, has been studied. To investigate the behaviour of the type of composite structures considered, numerous full-scale tests and numerical simulations have been conducted for both arched and box shapes of the shell. In addition, researchers have examined different span lengths and cover depths. Furthermore, to enhance the load-bearing capacity of the composite structures, various stiffening elements have been applied and tested. The reviewshows that the mechanical features of SSCSs are mainly based on the interaction of the shell with the soil backfill. The structures, as a composite system, become appropriately stiff when completely backfilled. For this reason, the construction phase corresponds to the highest values of shell displacement and stress. Moreover, the method of laying and compacting the backfill, as well as the thickness of the cover, has a significant impact on the behaviour of the structure at the stage of operation in both the quantitative and qualitative sense. Finally, a limited number of studies are conducted on the ultimate bearing capacity of large-span SSCS and various reinforcing methods. Considerably more works will need to be done on this topic. It applies to both full scale tests and numerical analysis.
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Authors and Affiliations

Alemu Mosisa Legese
1
ORCID: ORCID
Maciej Sobótka
1
ORCID: ORCID
Czesław Machelski
1
ORCID: ORCID
Adrian Różański
1
ORCID: ORCID

  1. Wrocław University of Science and Technology, Faculty of Civil Engineering, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
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Abstract

The mechanical properties of cement paste modified by nano-TiO2 (nT) and nano-SiO2 (nS) were experimentally studied. The compressive strength increased first and then decreased with the increase of nanoparticle content. When nanoparticles were added into the cement paste as a filler to improve the microstructure, the two kinds of particles both could form a tighter mesh structure, which would enhance the density and strength of the structure. The elastic modulus increased rapidly with the increase of the nT content and reached a peak when the nanoparticle content is about 3%, which was about twice the elastic modulus of ordinary cement paste. The Scanning electron microscopy (SEM) observation results showed that the microstructure of cement was network connection and fiber tube. The hydration progress of ordinary cement slurry was insufficient, and many unreacted cement particles remained. With the addition of nanoparticles, the internal structure of the cement became denser, with fewer pore cracks, smaller pore diameters, more complex fiber tube arrangements, and significant anisotropy, thereby improving strength and mechanical properties.

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Authors and Affiliations

Zhi Wang
Wenjing Qin
Lijuan Zhang
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Abstract

The effect of air humidity on transonic flow around an NACA0012 airfoil at flow conditions, characteristic for buffet phenomenon, was investigated experimentally. Airfoil angles of attack in the range from 6° up to 10° were used, whereas values of initial relative air humidity were kept constant at four values 12%, 40%, 60% and 80%. Reconstructed time depending airfoil pressure distributions, time histories of normal aerodynamic force coefficient C, as well values of C0 pulsation are shown on the basis of surface pressure measurements at various humidity levels. The influence of the air humidity on the buffet origin is presented.
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Authors and Affiliations

Z. Nosal
W.C. Selerowicz
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Abstract

This contribution gives an overview about new procedures for the parameter identification for the material characterisation of rubber blends. They are based on a Newton-Raphson procedure and a genetic algorithm. As basis serves an experimental investigation of the viscous properties of rubber blends by means of a capillaryviscometer. Because of simultaneous consideration of wall slippage, temperature and of the die swell, the proposed material characterisation is represented by a coupled system of nonlinear equations. Describing their solutions requires a numerical integration algorithm. For this purpose a generalized Newton-Raphson scheme has been adopted. The verification of the developed parameter identification was done by means of another approach which is based on a genetic algorithm.
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Authors and Affiliations

Herbert W. Mullner
Josef Eberhardsteiner
Andre Wieczorek

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