Search results for: AP/HTPB composite solid propellant

Authors: Josef Drahorad, Milos Beran, Ondrej Vltavsky, Marian Urban, Martin Fronek, Jiri Sova

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Engineering efforts of researchers of the Food research institute Prague and the Czech Technical University in spray drying technologies led to the introduction of a demonstrator ATOMIZER and a new technology of Carbon Dioxide-Assisted Spray Nebulization Drying (CASND). The equipment combines the spray drying technology, when the liquid to be dried is atomized by a rotary atomizer, with Carbon Dioxide Assisted Nebulization - Bubble Dryer (CAN-BD) process in an original way. A solution, emulsion or suspension is saturated by carbon dioxide at pressure up to 80 bar before the drying process. The atomization process takes place in two steps. In the first step, primary droplets are produced at the outlet of the rotary atomizer of special construction. In the second step, the primary droplets are divided in secondary droplets by the CO2 expansion from the inside of primary droplets. The secondary droplets, usually in the form of microbubbles, are rapidly dried by warm air stream at temperatures up to 60ºC and solid particles are formed in a drying chamber. Powder particles are separated from the drying air stream in a high efficiency fine powder separator. The product is frequently in the form of submicron hollow spheres. The CASND technology has been used to produce microparticulated protein concentrates for human nutrition from alternative plant sources - hemp and canola seed filtration cakes. Alkali extraction was used to extract the proteins from the filtration cakes. The protein solutions after the alkali extractions were dried with the demonstrator ATOMIZER. Aerosol particle size distribution and concentration in the draying chamber were determined by two different on-line aerosol spectrometers SMPS (Scanning Mobility Particle Sizer) and APS (Aerodynamic Particle Sizer). The protein powders were in form of hollow spheres with average particle diameter about 600 nm. The particles were characterized by the SEM method. The functional properties of the microparticulated protein concentrates were compared with the same protein concentrates dried by the conventional spray drying process. Microparticulated protein has been proven to have improved foaming and emulsifying properties, water and oil absorption capacities and formed long-term stable water dispersions. This work was supported by the research grants TH03010019 of the Technology Agency of the Czech Republic.

Keywords: carbon dioxide-assisted spray nebulization drying, canola seed, hemp seed, microparticulated proteins

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Authors: L. Chiriatti, H. Hafid, H. R. Mercado-Mendoza, K. L. Apedo, C. Fond, F. Feugeas

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Substituting natural aggregate with recycled aggregate coming from concrete demolition represents a promising alternative to face the issues of both the depletion of natural resources and the congestion of waste storage facilities. However, the crushing process of concrete demolition waste, currently in use to produce recycled concrete aggregate, does not allow the complete separation of natural aggregate from a variable amount of adhered mortar. Given the physicochemical characteristics of the latter, the introduction of recycled concrete aggregate into a concrete mix modifies, to a certain extent, both fresh and hardened concrete properties. As a consequence, the behavior of recycled reinforced concrete members could likely be influenced by the specificities of recycled concrete aggregates. Beyond the mechanical properties of concrete, and as a result of the composite character of reinforced concrete, the bond characteristics at the rebar/concrete interface have to be taken into account in an attempt to describe accurately the mechanical response of recycled reinforced concrete members. Hence, a comparative experimental campaign, including 16 pull-out tests, was carried out. Four concrete mixes with different recycled concrete aggregate content were tested. The main mechanical properties (compressive strength, tensile strength, Young’s modulus) of each concrete mix were measured through standard procedures. A single 14-mm-diameter ribbed rebar, representative of the diameters commonly used in the domain of civil engineering, was embedded into a 200-mm-side concrete cube. The resulting concrete cover is intended to ensure a pull-out type failure (i.e. exceedance of the rebar/concrete interface shear strength). A pull-out test carried out on the 100% recycled concrete specimen was enriched with exploratory acoustic emission measurements. Acoustic event location was performed by means of eight piezoelectric transducers distributed over the whole surface of the specimen. The resulting map was compared to existing data related to natural aggregate concrete. Damage distribution around the reinforcement and main features of the characteristic bond stress/free-end slip curve appeared to be similar to previous results obtained through comparable studies carried out on natural aggregate concrete. This seems to show that the usual bond mechanism sequence (‘chemical adhesion’, mechanical interlocking and friction) remains unchanged despite the addition of recycled concrete aggregate. However, the results also suggest that bond efficiency seems somewhat improved through the use of recycled concrete aggregate. This observation appears to be counter-intuitive with regard to the diminution of the main concrete mechanical properties with the recycled concrete aggregate content. As a consequence, the impact of recycled concrete aggregate content on bond characteristics seemingly represents an important factor which should be taken into account and likely to be further explored in order to determine flexural parameters such as deflection or crack distribution.

Keywords: acoustic emission monitoring, high-bond steel rebar, pull-out test, recycled aggregate concrete

Procedia PDF Downloads 159

Authors: Lidiia Nazarenko, Henryk Stolarski, Holm Altenbach

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In the paper, a (hierarchical) approach to analysis of thermo-elastic properties of random composites with interphases is outlined and illustrated. It is based on the statistical homogenization method – the method of conditional moments – combined with recently introduced notion of the energy-equivalent inhomogeneity which, in this paper, is extended to include thermal effects. After exposition of the general principles, the approach is applied in the investigation of the effective thermo-elastic properties of a material with randomly distributed nanoparticles. The basic idea of equivalent inhomogeneity is to replace the inhomogeneity and the surrounding it interphase by a single equivalent inhomogeneity of constant stiffness tensor and coefficient of thermal expansion, combining thermal and elastic properties of both. The equivalent inhomogeneity is then perfectly bonded to the matrix which allows to analyze composites with interphases using techniques devised for problems without interphases. From the mechanical viewpoint, definition of the equivalent inhomogeneity is based on Hill’s energy equivalence principle, applied to the problem consisting only of the original inhomogeneity and its interphase. It is more general than the definitions proposed in the past in that, conceptually and practically, it allows to consider inhomogeneities of various shapes and various models of interphases. This is illustrated considering spherical particles with two models of interphases, Gurtin-Murdoch material surface model and spring layer model. The resulting equivalent inhomogeneities are subsequently used to determine effective thermo-elastic properties of randomly distributed particulate composites. The effective stiffness tensor and coefficient of thermal extension of the material with so defined equivalent inhomogeneities are determined by the method of conditional moments. Closed-form expressions for the effective thermo-elastic parameters of a composite consisting of a matrix and randomly distributed spherical inhomogeneities are derived for the bulk and the shear moduli as well as for the coefficient of thermal expansion. Dependence of the effective parameters on the interphase properties is included in the resulting expressions, exhibiting analytically the nature of the size-effects in nanomaterials. As a numerical example, the epoxy matrix with randomly distributed spherical glass particles is investigated. The dependence of the effective bulk and shear moduli, as well as of the effective thermal expansion coefficient on the particle volume fraction (for different radii of nanoparticles) and on the radius of nanoparticle (for fixed volume fraction of nanoparticles) for different interphase models are compared to and discussed in the context of other theoretical predictions. Possible applications of the proposed approach to short-fiber composites with various types of interphases are discussed.

Keywords: effective properties, energy equivalence, Gurtin-Murdoch surface model, interphase, random composites, spherical equivalent inhomogeneity, spring layer model

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Authors: Maciej Szeląg, Stanisław Fic

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The impact of elevated temperatures on the construction materials manifests in change of their physical and mechanical characteristics. Stresses and thermal deformations that occur inside the volume of the material cause its progressive degradation as temperature increase. Finally, the reactions and transformations of multiphase structure of cementitious composite cause its complete destruction. A particularly dangerous phenomenon is the impact of thermal shock – a sudden high temperature load. The thermal shock leads to a high value of the temperature gradient between the outer surface and the interior of the element in a relatively short time. The result of mentioned above process is the formation of the cracks and scratches on the material’s surface and inside the material. The article describes the use of computer image analysis techniques to identify and assess the structure of the cluster cracks on the surfaces of modified cement pastes, caused by thermal shock. Four series of specimens were tested. Two Portland cements were used (CEM I 42.5R and CEM I 52,5R). In addition, two of the series contained metakaolinite as a replacement for 10% of the cement content. Samples in each series were made in combination of three w/b (water/binder) indicators of respectively 0.4; 0.5; 0.6. Surface cracks of the samples were created by a sudden temperature load at 200°C for 4 hours. Images of the cracked surfaces were obtained via scanning at 1200 DPI; digital processing and measurements were performed using ImageJ v. 1.46r software. In order to examine the cracked surface of the cement paste as a system of closed clusters – the dispersal systems theory was used to describe the structure of cement paste. Water is used as the dispersing phase, and the binder is used as the dispersed phase – which is the initial stage of cement paste structure creation. A cluster itself is considered to be the area on the specimen surface that is limited by cracks (created by sudden temperature loading) or by the edge of the sample. To describe the structure of cracks two stereological parameters were proposed: A ̅ – the cluster average area, L ̅ – the cluster average perimeter. The goal of this study was to compare the investigated stereological parameters with the mechanical properties of the tested specimens. Compressive and tensile strength testes were carried out according to EN standards. The method used in the study allowed the quantitative determination of defects occurring in the examined modified cement pastes surfaces. Based on the results, it was found that the nature of the cracks depends mainly on the physical parameters of the cement and the intermolecular interactions on the dispersal environment. Additionally, it was noted that the A ̅/L ̅ relation of created clusters can be described as one function for all tested samples. This fact testifies about the constant geometry of the thermal cracks regardless of the presence of metakaolinite, the type of cement and the w/b ratio.

Keywords: cement paste, cluster cracks, elevated temperature, image analysis, metakaolinite, stereological parameters

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Authors: Stojan Kravanja, Andrej Ivanič, Tomaž Žula

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This contribution focuses on structural optimization in civil engineering using mixed integer non-linear programming (MINLP). MINLP is characterized as a versatile method that can handle both continuous and discrete optimization variables simultaneously. Continuous variables are used to optimize parameters such as dimensions, stresses, masses, or costs, while discrete variables represent binary decisions to determine the presence or absence of structural elements within a structure while also calculating discrete materials and standard sections. The optimization process is divided into three main steps. First, a mechanical superstructure with a variety of different topology-, material- and dimensional alternatives. Next, a MINLP model is formulated to encapsulate the optimization problem. Finally, an optimal solution is searched in the direction of the defined objective function while respecting the structural constraints. The economic or mass objective function of the material and labor costs of a structure is subjected to the constraints known from structural analysis. These constraints include equations for the calculation of internal forces and deflections, as well as equations for the dimensioning of structural components (in accordance with the Eurocode standards). Given the complex, non-convex and highly non-linear nature of optimization problems in civil engineering, the Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm is applied. This algorithm alternately solves subproblems of non-linear programming (NLP) and main problems of mixed-integer linear programming (MILP), in this way gradually refines the solution space up to the optimal solution. The NLP corresponds to the continuous optimization of parameters (with fixed topology, discrete materials and standard dimensions, all determined in the previous MILP), while the MILP involves a global approximation to the superstructure of alternatives, where a new topology, materials, standard dimensions are determined. The optimization of a convex problem is stopped when the MILP solution becomes better than the best NLP solution. Otherwise, it is terminated when the NLP solution can no longer be improved. While the OA/ER algorithm, like all other algorithms, does not guarantee global optimality due to the presence of non-convex functions, various modifications, including convexity tests, are implemented in OA/ER to mitigate these difficulties. The effectiveness of the proposed MINLP approach is demonstrated by its application to various structural optimization tasks, such as mass optimization of steel buildings, cost optimization of timber halls, composite floor systems, etc. Special optimization models have been developed for the optimization of these structures. The MINLP optimizations, facilitated by the user-friendly software package MIPSYN, provide insights into a mass or cost-optimal solutions, optimal structural topologies, optimal material and standard cross-section choices, confirming MINLP as a valuable method for the optimization of structures in civil engineering.

Keywords: MINLP, mixed-integer non-linear programming, optimization, structures

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Authors: Yakup Ulusu, Faruk Ozel, Numan Eczacioglu, Abdurrahman Ozen, Sabriye Acikgoz

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GFP discovered in the mid-1970s, has been used as a marker after replicated genetic study by scientists. In biotechnology, cell, molecular biology, the GFP gene is frequently used as a reporter of expression. In modified forms, it has been used to make biosensors. Many animals have been created that express GFP as an evidence that a gene can be expressed throughout a given organism. Proteins labeled with GFP identified locations are determined. And so, cell connections can be monitored, gene expression can be reported, protein-protein interactions can be observed and signals that create events can be detected. Additionally, monitoring GFP is noninvasive; it can be detected by under UV-light because of simply generating fluorescence. Moreover, GFP is a relatively small and inert molecule, that does not seem to treat any biological processes of interest. The synthesis of GFP has some steps like, to construct the plasmid system, transformation in E. coli, production and purification of protein. GFP carrying plasmid vector pBAD–GFPuv was digested using two different restriction endonuclease enzymes (NheI and Eco RI) and DNA fragment of GFP was gel purified before cloning. The GFP-encoding DNA fragment was ligated into pET28a plasmid using NheI and Eco RI restriction sites. The final plasmid was named pETGFP and DNA sequencing of this plasmid indicated that the hexa histidine-tagged GFP was correctly inserted. Histidine-tagged GFP was expressed in an Escherichia coli BL21 DE3 (pLysE) strain. The strain was transformed with pETGFP plasmid and grown on LuiraBertoni (LB) plates with kanamycin and chloramphenicol selection. E. coli cells were grown up to an optical density (OD 600) of 0.8 and induced by the addition of a final concentration of 1mM isopropyl-thiogalactopyranoside (IPTG) and then grown for additional 4 h. The amino-terminal hexa-histidine-tag facilitated purification of the GFP by using a His Bind affinity chromatography resin (Novagen). Purity of GFP protein was analyzed by a 12 % sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The concentration of protein was determined by UV absorption at 280 nm (Varian Cary 50 Scan UV/VIS spectrophotometer). Synthesis of GFP-Polymer composite nanofibers was produced by using GFP solution (10mg/mL) and polymer precursor Polyvinylpyrrolidone, (PVP, Mw=1300000) as starting materials and template, respectively. For the fabrication of nanofibers with the different fiber diameter; a sol–gel solution comprising of 0.40, 0.60 and 0.80 g PVP (depending upon the desired fiber diameter) and 100 mg GFP in 10 mL water: ethanol (3:2) mixtures were prepared and then the solution was covered on collecting plate via electro spinning at 10 kV with a feed-rate of 0.25 mL h-1 using Spellman electro spinning system. Results show that GFP-based nano-fiber can be used plenty of biomedical applications such as bio-imaging, bio-mechanic, bio-material and tissue engineering.

Keywords: biomaterial, GFP, nano-fibers, protein expression

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Authors: Muhammed Ertugrul Celoglu, Beyza Furtana, Mehmet Yilmaz, Baha Vural Kok

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Biomass, which is considered to be one of the largest renewable energy sources in the world, has a potential to be utilized as a bitumen additive after it is processed by a wide variety of thermochemical methods. Furthermore, biomasses are renewable in short amounts of time, and they possess a hydrocarbon structure. These characteristics of biomass promote their usability as additives. One of the most common ways to create materials with significant economic values from biomasses is the processes of pyrolysis. Pyrolysis is defined as the process of an organic matter’s thermochemical degradation (carbonization) at a high temperature and in an anaerobic environment. The resultant liquid substance at the end of the pyrolysis is defined as bio-oil, whereas the resultant solid substance is defined as biochar. Olive pomace is the resultant mildly oily pulp with seeds after olive is pressed and its oil is extracted. It is a significant source of biomass as the waste of olive oil factories. Because olive pomace is waste material, it could create problems just as other waste unless there are appropriate and acceptable areas of utilization. The waste material, which is generated in large amounts, is generally used as fuel and fertilizer. Generally, additive materials are used in order to improve the properties of bituminous binders, and these are usually expensive materials, which are produced chemically. The aim of this study is to investigate the usability of biochars obtained after subjecting olive pomace and smashed olive seeds, which are considered as waste materials, to pyrolysis as additives in bitumen modification. In this way, various ways of use will be provided for waste material, providing both economic and environmental benefits. In this study, olive pomace and smashed olive seeds were used as sources of biomass. Initially, both materials were ground and processed through a No.50 sieve. Both of the sieved materials were subjected to pyrolysis (carbonization) at 400 ℃. Following the process of pyrolysis, bio-oil and biochar were obtained. The obtained biochars were added to B160/220 grade pure bitumen at 10% and 15% rates and modified bitumens were obtained by mixing them in high shear mixtures at 180 ℃ for 1 hour at 2000 rpm. Pure bitumen and four different types of bitumen obtained as a result of the modifications were tested with penetration, softening point, rotational viscometer, and dynamic shear rheometer, evaluating the effects of additives and the ratios of additives. According to the test results obtained, both biochar modifications at both ratios provided improvements in the performance of pure bitumen. In the comparison of the test results of the binders modified with the biochars of olive pomace and smashed olive seed, it was revealed that there was no notable difference in their performances.

Keywords: bituminous binders, biochar, biomass, olive pomace, pomace, pyrolysis

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Authors: Ming-Hsiang Shih, Wen-Pei Sung, Shih-Heng Tung

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The purposes of hydraulic gate are to maintain the functions of storing and draining water. It bears long-term hydraulic pressure and earthquake force and is very important for reservoir and waterpower plant. The high tensile strength of steel plate is used as constructional material of hydraulic gate. The cracks and rusts, induced by the defects of material, bad construction and seismic excitation and under water respectively, thus, the mechanics phenomena of gate with crack are probing into the cause of stress concentration, induced high crack increase rate, affect the safety and usage of hydroelectric power plant. Stress distribution analysis is a very important and essential surveying technique to analyze bi-material and singular point problems. The finite difference infinitely small element method has been demonstrated, suitable for analyzing the buckling phenomena of welding seam and steel plate with crack. Especially, this method can easily analyze the singularity of kink crack. Nevertheless, the construction form and deformation shape of some gates are three-dimensional system. Therefore, the three-dimensional Digital Image Correlation (DIC) has been developed and applied to analyze the strain variation of steel plate with crack at weld joint. The proposed Digital image correlation (DIC) technique is an only non-contact method for measuring the variation of test object. According to rapid development of digital camera, the cost of this digital image correlation technique has been reduced. Otherwise, this DIC method provides with the advantages of widely practical application of indoor test and field test without the restriction on the size of test object. Thus, the research purpose of this research is to develop and apply this technique to monitor mechanics crack variations of weld steel hydraulic gate and its conformation under action of loading. The imagines can be picked from real time monitoring process to analyze the strain change of each loading stage. The proposed 3-Dimensional digital image correlation method, developed in the study, is applied to analyze the post-buckling phenomenon and buckling tendency of welded steel plate with crack. Then, the stress intensity of 3-dimensional analysis of different materials and enhanced materials in steel plate has been analyzed in this paper. The test results show that this proposed three-dimensional DIC method can precisely detect the crack variation of welded steel plate under different loading stages. Especially, this proposed DIC method can detect and identify the crack position and the other flaws of the welded steel plate that the traditional test methods hardly detect these kind phenomena. Therefore, this proposed three-dimensional DIC method can apply to observe the mechanics phenomena of composite materials subjected to loading and operating.

Keywords: welded steel plate, crack variation, three-dimensional digital image correlation (DIC), crack stel plate

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Authors: Nor Azian Binti Aziz, Muhammad Afiq Bin Tambichik, Zamri Bin Hashim

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The rapid development of the construction industry has contributed to increased construction waste, with concrete waste being among the most abundant. This waste is generated from ready-mix batching plants after the concrete cube testing process is completed and disposed of in landfills, leading to increased solid waste management costs. This study aims to evaluate the engineering characteristics of foamed concrete with waste mixtures construction and agricultural waste to determine the usability of recycled materials in the construction of non-load-bearing walls. This study involves the collection of construction wastes, such as recycled aggregates (RCA) obtained from the remains of finished concrete cubes, which are then tested in the laboratory. Additionally, agricultural waste, such as rice husk ash, is mixed into foamed concrete interlock blocks to enhance their strength. The optimal density of foamed concrete for this study was determined by mixing mortar and foam-backed agents to achieve the minimum targeted compressive strength required for non-load-bearing walls. The tests conducted in this study involved two phases. In Phase 1, elemental analysis using an X-ray fluorescence spectrometer (XRF) was conducted on the materials used in the production of interlock blocks such as sand, recycled aggregate/recycled concrete aggregate (RCA), and husk ash paddy/rice husk ash (RHA), Phase 2 involved physical and thermal tests, such as compressive strength test, heat conductivity test, and fire resistance test, on foamed concrete mixtures. The results showed that foamed concrete can produce lightweight interlock blocks. X-ray fluorescence spectrometry plays a crucial role in the characterization, quality control, and optimization of foamed concrete mixes containing construction and agriculture waste. The unique composition mixer of foamed concrete and the resulting chemical and physical properties, as well as the nature of replacement (either as cement or fine aggregate replacement), the waste contributes differently to the performance of foamed concrete. Interlocking blocks made from foamed concrete can be advantageous due to their reduced weight, which makes them easier to handle and transport compared to traditional concrete blocks. Additionally, foamed concrete typically offers good thermal and acoustic insulation properties, making it suitable for a variety of building projects. Using foamed concrete to produce lightweight interlock blocks could contribute to more efficient and sustainable construction practices. Additionally, RCA derived from concrete cube waste can serve as a substitute for sand in producing lightweight interlock blocks.

Keywords: construction waste, recycled aggregates (RCA), sustainable concrete, structure material

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Authors: Raphael Palucci Rosa, Giuseppe Rosace

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Stereolithography (SLA) is one of the 3D-printing technologies that has been steadily growing in popularity for both industrial and personal applications due to its versatility, high accuracy, and low cost. Its printing process consists of using a light emitter to solidify photosensitive liquid resins layer-by-layer to produce solid objects. However, the majority of the resins used in SLA are derived from petroleum and characterized by toxicity, stability, and recalcitrance to degradation in natural environments. Aiming to develop an eco-friendly resin, in this work, different combinations of a standard commercial SLA resin (Peopoly UV professional) with a vegetable-based resin were investigated. To reach this goal, different mass concentrations (varying from 10 to 50 wt%) of acrylated epoxidized soybean oil (AESO), a vegetable resin produced from soyabean oil, were mixed with a commercial acrylate-based resin. 1.0 wt% of Diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) was used as photo-initiator, and the samples were printed using a Peopoly moai 130. The machine was set to operate at standard configurations when printing commercial resins. After the print was finished, the excess resin was drained off, and the samples were washed in isopropanol and water to remove any non-reacted resin. Finally, the samples were post-cured for 30 min in a UV chamber. FT-IR analysis was used to confirm the UV polymerization of the formulated resin with different AESO/Peopoly ratios. The signals from 1643.7 to 1616, which corresponds to the C=C stretching of the AESO acrylic acids and Peopoly acrylic groups, significantly decreases after the reaction. The signal decrease indicates the consumption of the double bonds during the radical polymerization. Furthermore, the slight change of the C-O-C signal from 1186.1 to 1159.9 decrease of the signals at 809.5 and 983.1, which corresponds to unsaturated double bonds, are both proofs of the successful polymerization. Mechanical analyses showed a decrease of 50.44% on tensile strength when adding 10 wt% of AESO, but it was still in the same range as other commercial resins. The elongation of break increased by 24% with 10 wt% of AESO and swelling analysis showed that samples with a higher concentration of AESO mixed absorbed less water than their counterparts. Furthermore, high-resolution prototypes were printed using both resins, and visual analysis did not show any significant difference between both products. In conclusion, the AESO resin was successful incorporated into a commercial resin without affecting its printability. The bio-based resin showed lower tensile strength than the Peopoly resin due to network loosening, but it was still in the range of other commercial resins. The hybrid resin also showed better flexibility and water resistance than Peopoly resin without affecting its resolution. Finally, the development of new types of SLA resins is essential to provide new sustainable alternatives to the commercial petroleum-based ones.

Keywords: 3D-printing, bio-based, resin, soybean, stereolithography

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Authors: Chuanqiao Zheng, Wei Zeng, Haozhen Lin

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As of March 2020, the number of Chinese netizens has reached 904 million. The proportion of Internet users accessing the Internet through mobile phones is as high as 99.3%. Under the background of 'Internet +', tourists have a stronger sense of independence in the choice of tourism destinations and tourism products. Tourists are more inclined to learn about the relevant information on tourism destinations and other tourists' evaluations of tourist products through the Internet. The search engine, as an integrated platform that contains a wealth of information, is highly valuable to the analysis of the characteristics of the Internet attention given to various tourism destinations, through big data mining and analysis. This article uses the Baidu Index as the data source, which is one of the products of Baidu Search. The Baidu Index is based on big data, which collects and shares the search results of a large number of Internet users on the Baidu search engine. The big data used in this article includes search index, demand map, population profile, etc. The main research methods used are: (1) based on the search index, analyzing the Internet attention given to the tourism in five cities in Northeast Sichuan at different times, so as to obtain the overall trend and individual characteristics of tourism development in the region; (2) based on the demand map and the population profile, analyzing the demographic characteristics and market positioning of the tourist groups in these cities to understand the characteristics and needs of the target groups; (3) correlating the Internet attention data with the permanent population of each province in China in the corresponding to construct the Boston matrix of the Internet attention rate of the Northeast Sichuan tourism, obtain the tourism target markets, and then propose development strategies for different markets. The study has found that: a) the Internet attention given to the tourism in the region can be categorized into tourist off-season and peak season; the Internet attention given to tourism in different cities is quite different. b) tourists look for information including tour guide information, ticket information, traffic information, weather information, and information on the competing tourism cities; with regard to the population profile, the main group of potential tourists searching for the keywords of tourism in the five prefecture-level cities in Northeast Sichuan are youth. The male to female ratio is about 6 to 4, with males being predominant. c) through the construction of the Boston matrix, it is concluded that the star market for tourism in the Northeast Sichuan Economic Zone includes Sichuan and Shaanxi; the cash cows market includes Hainan and Ningxia; the question market includes Jiangsu and Shanghai; the dog market includes Hubei and Jiangxi. The study concludes with the following planning strategies and recommendations: i) creating a diversified business format that integrates cultural and tourism; ii) creating a brand image of niche tourism; iii) focusing on the development of tourism products; iv) innovating composite three-dimensional marketing channels.

Keywords: Baidu Index, big data, internet attention, tourism

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Authors: David Schafer

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Critical Theory is in sore need of a workable account of technology. It had one in the writings of Herbert Marcuse, or so it seemed until Jürgen Habermas mounted a critique in 'Technology and Science as Ideology' (Habermas, 1970) that decisively put it away. Ever since Marcuse’s work has been regarded outdated – a 'philosophy of consciousness' no longer seriously tenable. But with Marcuse’s view has gone the important insight that technology is no norm-free system (as Habermas portrays it) but can be laden with social bias. Andrew Feenberg is among a few serious scholars who have perceived this problem in post-Habermasian critical theory and has sought to revive a basically Marcusean account of technology. On his view, while so-called ‘technical elements’ that physically make up technologies are neutral with regard to social interests, there is a sense in which we may speak of a normative grammar or ‘technical code’ built-in to technology that can be socially biased in favor of certain groups over others (Feenberg, 2002). According to Feenberg, those perspectives on technology are reified which consider technology only by their technical elements to the neglect of their technical codes. Nevertheless, Feenberg’s account fails to explain what is normatively problematic with such reified views of technology. His plausible claim that they represent false perspectives on technology by itself does not explain how such views may be oppressive, even though Feenberg surely wants to be doing that stronger level of normative theorizing. Perceiving this deficit in his own account of reification, he tries to adopt Habermas’s version of systems-theory to ground his own critical theory of technology (Feenberg, 1999). But this is a curious move in light of Feenberg’s own legitimate critiques of Habermas’s portrayals of technology as reified or ‘norm-free.’ This paper argues that a better foundation may be found in Axel Honneth’s recent text, Freedom’s Right (Honneth, 2014). Though Honneth there says little explicitly about technology, he offers an implicit account of reification formulated in opposition to Habermas’s systems-theoretic approach. On this ‘normative functionalist’ account of reification, social spheres are reified when participants prioritize individualist ideals of freedom (moral and legal freedom) to the neglect of an intersubjective form of freedom-through-recognition that Honneth calls ‘social freedom.’ Such misprioritization is ultimately problematic because it is unsustainable: individual freedom is philosophically and institutionally dependent upon social freedom. The main difficulty in adopting Honneth’s social theory for the purposes of a theory of technology, however, is that the notion of social freedom is predicable only of social institutions, whereas it appears difficult to conceive of technology as an institution. Nevertheless, in light of Feenberg’s work, the idea that technology includes within itself a normative grammar (technical code) takes on much plausibility. To the extent that this normative grammar may be understood by the category of social freedom, Honneth’s dialectical account of the relationship between individual and social forms of freedom provides a more solid basis from which to ground the normative claims of Feenberg’s sociological account of technology than Habermas’s systems theory.

Keywords: Habermas, Honneth, technology, Feenberg

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Authors: Maria Fontenele, Claude-Gilles Dussap, Vincent Dumouilla, Baptiste Boit

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Roquette Frères is a producer of plant-based ingredients that employs many processes to extract relevant molecules and often transforms them through chemical and physical processes to create desired ingredients with specific functionalities. In this context, Roquette encounters numerous multi-component complex systems in their processes, including fibers, proteins, and carbohydrates, in an aqueous environment. To develop, control, and optimize both new and old processes, Roquette aims to develop new in silico tools. Currently, Roquette uses process modelling tools which include specific thermodynamic models and is willing to develop computational methodologies such as molecular dynamics simulations to gain insights into the complex interactions in such complex media, and especially hydrogen bonding interactions. The issue at hand concerns aqueous mixtures of polyols with high dry matter content. The polyols mannitol and sorbitol molecules are diastereoisomers that have nearly identical chemical structures but very different physicochemical properties: for example, the solubility of sorbitol in water is 2.5 kg/kg of water, while mannitol has a solubility of 0.25 kg/kg of water at 25°C. Therefore, predicting liquid-solid equilibrium properties in this case requires sophisticated solution models that cannot be based solely on chemical group contributions, knowing that for mannitol and sorbitol, the chemical constitutive groups are the same. Recognizing the significance of solvation phenomena in polyols, the GePEB (Chemical Engineering, Applied Thermodynamics, and Biosystems) team at Institut Pascal has developed the COSMO-UCA model, which has the structural advantage of using quantum mechanics tools to predict formation and phase equilibrium properties. In this work, we use molecular dynamics simulations to elucidate the behavior of polyols in aqueous solution. Specifically, we employ simulations to compute essential metrics such as radial distribution functions and hydrogen bond autocorrelation functions. Our findings illuminate a fundamental contrast: sorbitol and mannitol exhibit disparate hydrogen bond lifetimes within aqueous environments. This observation serves as a cornerstone in elucidating the divergent physicochemical properties inherent to each compound, shedding light on the nuanced interplay between their molecular structures and water interactions. We also present a methodology to predict the physicochemical properties of complex solutions, taking as sole input the three-dimensional structure of the molecules in the medium. Finally, by developing knowledge models, we represent some physicochemical properties of aqueous solutions of sorbitol and mannitol.

Keywords: COSMO models, hydrogen bond, molecular dynamics, thermodynamics

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Authors: Zhuoran Li, Guan Qin

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A robust and efficient compositional equilibrium characterization model for hydrate-containing systems is required, especially for time-critical simulations such as subsea pipeline flow assurance analysis, compositional simulation in hydrate reservoirs etc. A multiphase flash calculation framework, which combines Gibbs energy minimization function and cubic plus association (CPA) EoS, is developed to describe the highly non-ideal phase behavior of hydrate-containing systems. A non-iterative eigenvalue problem-solving approach for the trust-region sub-problem is selected to guarantee efficiency. The developed flash model is based on the state-of-the-art objective function proposed by Michelsen to minimize the Gibbs energy of the multiphase system. It is conceivable that a hydrate-containing system always contains polar components (such as water and hydrate inhibitors), introducing hydrogen bonds to influence phase behavior. Thus, the cubic plus associating (CPA) EoS is utilized to compute the thermodynamic parameters. The solid solution theory proposed by van der Waals and Platteeuw is applied to represent hydrate phase parameters. The trust-region method combined with the trust-region sub-problem non-iterative eigenvalue problem-solving approach is utilized to ensure fast convergence. The developed multiphase flash model's accuracy performance is validated by three available models (one published and two commercial models). Hundreds of published hydrate-containing system equilibrium experimental data are collected to act as the standard group for the accuracy test. The accuracy comparing results show that our model has superior performances over two models and comparable calculation accuracy to CSMGem. Efficiency performance test also has been carried out. Because the trust-region method can determine the optimization step's direction and size simultaneously, fast solution progress can be obtained. The comparison results show that less iteration number is needed to optimize the objective function by utilizing trust-region methods than applying line search methods. The non-iterative eigenvalue problem approach also performs faster computation speed than the conventional iterative solving algorithm for the trust-region sub-problem, further improving the calculation efficiency. A new thermodynamic framework of the multiphase flash model for the hydrate-containing system has been constructed in this work. Sensitive analysis and numerical experiments have been carried out to prove the accuracy and efficiency of this model. Furthermore, based on the current thermodynamic model in the oil and gas industry, implementing this model is simple.

Keywords: equation of state, hydrates, multiphase equilibrium, trust-region method

Procedia PDF Downloads 160

Authors: Stephanie PB Caligiuri, Harold M Aukema, Delfin Rodriguez-Leyva, Amir Ravandi, Randy Guzman, Grant N. Pierce

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Background: Hypertension leads to cardiac and cerebral events and therefore is the leading risk factor attributed to death in the world. Oxylipins may be mediators in these events as they can regulate vascular tone and inflammation. Oxylipins are derived from fatty acids. Dietary flaxseed is rich in the n3 fatty acid, alpha-linolenic acid, and, therefore, may have the ability to change the substrate profile of oxylipins. As a result, this could alter blood pressure. Methods: A randomized, double-blinded, controlled clinical trial, the Flax-PAD trial, was used to assess the impact of dietary flaxseed on blood pressure (BP), and to also assess the relationship of plasma oxylipins to BP in 81 patients with peripheral arterial disease (PAD). Patients with PAD were chosen for the clinical trial as they are at an increased risk for hypertension and cardiac and cerebral events. Thirty grams of ground flaxseed were added to food products to consume on a daily basis for 6 months. The control food products contained wheat germ, wheat bran, and mixed dietary oils instead of flaxseed. Central BP, which is more significantly associated to organ damage, cardiac, and cerebral events versus brachial BP, was measured by pulse wave analysis at baseline and 6 months. A plasma profile of 43 oxylipins was generated using solid phase extraction, HPLC-MS/MS, and stable isotope dilution quantitation. Results: At baseline, the central BP (systolic/diastolic) in the placebo and flaxseed group were, 131/73 ± 2.5/1.4 mmHg and 128/71 ± 2.6/1.4 mmHg, respectively. After 6 months of intervention, the flaxseed group exhibited a decrease in blood pressure of 4.0/1.0 mmHg. The 6 month central BP in the placebo and flaxseed groups were, 132/74 ± 2.9/1.8 mmHg and 124/70 ± 2.6/1.6 mmHg (P<0.05). Correlation and logistic regression analyses between central blood pressure and oxylipins were performed. Significant associations were observed between central blood pressure and 17 oxylipins, primarily produced from arachidonic acid. Every 1 nM increase in 16-hydroxyeicosatetraenoic acid (HETE) increased the odds of having high central systolic BP by 15-fold, of having high central diastolic BP by 6-fold and of having high central mean arterial pressure by 15-fold. In addition, every 1 nM increase in 5,6-dihydroxyeicosatrienoic acid (DHET) and 11,12-DHET increased the odds of having high central mean arterial pressure by 45- and 18-fold, respectively. Flaxseed induced a significant decrease in these as well as 4 other vasoconstrictive oxylipins. Conclusion: Dietary flaxseed significantly lowered blood pressure in patients with PAD and hypertension. Plasma oxylipins were strongly associated with central blood pressure and may have mediated the flaxseed-induced decrease in blood pressure.

Keywords: hypertension, flaxseed, oxylipins, peripheral arterial disease

Procedia PDF Downloads 455

Authors: Dragan Ribarić

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We employ the so-called problem-dependent linked interpolation concept to develop two cubic 4-node quadrilateral Mindlin plate finite elements with 12 external degrees of freedom. In the problem-independent linked interpolation, the interpolation functions are independent of any problem material parameters and the rotation fields are not expressed in terms of the nodal displacement parameters. On the contrary, in the problem-dependent linked interpolation, the interpolation functions depend on the material parameters and the rotation fields are expressed in terms of the nodal displacement parameters. Two cubic 4-node quadrilateral plate elements are presented, named Q4-U3 and Q4-U3R5. The first one is modelled with one displacement and two rotation degrees of freedom in every of the four element nodes and the second element has five additional internal degrees of freedom to get polynomial completeness of the cubic form and which can be statically condensed within the element. Both elements are able to pass the constant-bending patch test exactly as well as the non-zero constant-shear patch test on the oriented regular mesh geometry in the case of cylindrical bending. In any mesh shape, the elements have the correct rank and only the three eigenvalues, corresponding to the solid body motions are zero. There are no additional spurious zero modes responsible for instability of the finite element models. In comparison with the problem-independent cubic linked interpolation implemented in Q9-U3, the nine-node plate element, significantly less degrees of freedom are employed in the model while retaining the interpolation conformity between adjacent elements. The presented elements are also compared to the existing problem-independent quadratic linked-interpolation element Q4-U2 and to the other known elements that also use the quadratic or the cubic linked interpolation, by testing them on several benchmark examples. Simple functional upgrading from the quadratic to the cubic linked interpolation, implemented in Q4-U3 element, showed no significant improvement compared to the quadratic linked form of the Q4-U2 element. Only when the additional bubble terms are incorporated in the displacement and rotation function fields, which complete the full cubic linked interpolation form, qualitative improvement is fulfilled in the Q4-U3R5 element. Nevertheless, the locking problem exists even for the both presented elements, like in all pure displacement elements when applied to very thin plates modelled by coarse meshes. But good and even slightly better performance can be noticed for the Q4-U3R5 element when compared with elements from the literature, if the model meshes are moderately dense and the plate thickness not extremely thin. In some cases, it is comparable to or even better than Q9-U3 element which has as many as 12 more external degrees of freedom. A significant improvement can be noticed in particular when modeling very skew plates and models with singularities in the stress fields as well as circular plates with distorted meshes.

Keywords: Mindlin plate theory, problem-independent linked interpolation, problem-dependent interpolation, quadrilateral displacement-based plate finite elements

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Authors: L. García, N. Cobas, M. López

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Acrylamide, a probable carcinogen, is formed in high-temperature processed food (>120ºC) when the free amino acid asparagine reacts with reducing sugars, mainly glucose and fructose. Cane juices' repeated heating would potentially form acrylamide during brown sugar production. This study aims to determine if using panela in yogurt cake preparation increases acrylamide formation. A secondary aim is to analyze the acrylamide concentration in four cake confections with different caloric sweetener ingredients: beet sugar (BS), cane sugar (CS), panela (P), and a panela and chocolate mix (PC). The doughs were obtained by combining ingredients in a planetary mixer. A model system made up of flour (25%), caloric sweeteners (25 %), eggs (23%), yogurt (15.7%), sunflower oil (9.4%), and brewer's yeast (2 %) was applied to BS, CS and P cakes. The ingredients of PC cakes varied: flour (21.5 %), panela chocolate (21.5 %), eggs (25.9 %), yogurt (18 %), sunflower oil (10.8 %), and brewer’s yeast (2.3 %). The preparations were baked for 45' at 180 ºC. Moisture was estimated by AOAC. Protein was determined by the Kjeldahl method. Ash percentage was calculated by weight loss after pyrolysis (≈ 600 °C). Fat content was measured using liquid-solid extraction in hydrolyzed raw ingredients and final confections. Carbohydrates were determined by difference and total sugars by the Luff-Schoorl method, based on the iodometric determination of copper ions. Finally, acrylamide content was determined by LC-MS by the isocratic system (phase A: 97.5 % water with 0.1% formic acid; phase B: 2.5 % methanol), using a standard internal procedure. Statistical analysis was performed using SPSS v.23. One-way variance analysis determined differences between acrylamide content and compositional analysis, with caloric sweeteners as fixed effect. Significance levels were determined by applying Duncan's t-test (p<0.05). P cakes showed a lower energy value than the other baked products; sugar content was similar to BS and CS, with 6.1 % mean crude protein. Acrylamide content in caloric sweeteners was similar to previously reported values. However, P and PC showed significantly higher concentrations, probably explained by the applied procedure. Acrylamide formation depends on both reducing sugars and asparagine concentration and availability. Beet sugar samples did not present acrylamide concentrations within the detection and quantification limit. However, the highest acrylamide content was measured in the BS. This may be due to the higher concentration of reducing sugars and asparagine in other raw ingredients. The cakes made with panela, cane sugar, or panela with chocolate did not differ in acrylamide content. The lack of asparagine measures constitutes a limitation. Cakes made with panela showed lower acrylamide formation than products elaborated with beet or cane sugar.

Keywords: beet sugar, cane sugar, panela, yogurt cake

Procedia PDF Downloads 58

Authors: Boukary Lam, Sebastien Deon, Patrick Fievet, Nadia Crini, Gregorio Crini

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Treatment of heavy metal-contaminated industrial wastewater has become a major challenge over the last decades. Conventional processes for the treatment of metal-containing effluents do not always simultaneously satisfy both legislative and economic criteria. In this context, coupling of processes can then be a promising alternative to the conventional approaches used by industry. The polymer-assisted ultrafiltration (PAUF) process is one of these coupling processes. Its principle is based on a sequence of steps with reaction (e.g., complexation) between metal ions and a polymer and a step involving the rejection of the formed species by means of a UF membrane. Unlike free ions, which can cross the UF membrane due to their small size, the polymer/ion species, the size of which is larger than pore size, are rejected. The PAUF process was deeply investigated herein in the case of removal of nickel ions by adding chitosan and carboxymethyl cellulose (CMC). Experiments were conducted with synthetic solutions containing 1 to 100 ppm of nickel ions with or without the presence of NaCl (0.05 to 0.2 M), and an industrial discharge water (containing several metal ions) with and without polymer. Chitosan with a molecular weight of 1.8×105 g mol⁻¹ and a degree of acetylation close to 15% was used. CMC with a degree of substitution of 0.7 and a molecular weight of 9×105 g mol⁻¹ was employed. Filtration experiments were performed under cross-flow conditions with a filtration cell equipped with a polyamide thin film composite flat-sheet membrane (3.5 kDa). Without the step of polymer addition, it was found that nickel rejection decreases from 80 to 0% with increasing metal ion concentration and salt concentration. This behavior agrees qualitatively with the Donnan exclusion principle: the increase in the electrolyte concentration screens the electrostatic interaction between ions and the membrane fixed the charge, which decreases their rejection. It was shown that addition of a sufficient amount of polymer (greater than 10⁻² M of monomer unit) can offset this decrease and allow good metal removal. However, the permeation flux was found to be somewhat reduced due to the increase in osmotic pressure and viscosity. It was also highlighted that the increase in pH (from 3 to 9) has a strong influence on removal performances: the higher pH value, the better removal performance. The two polymers have shown similar performance enhancement at natural pH. However, chitosan has proved more efficient in slightly basic conditions (above its pKa) whereas CMC has demonstrated very weak rejection performances when pH is below its pKa. In terms of metal rejection, chitosan is thus probably the better option for basic or strongly acid (pH < 4) conditions. Nevertheless, CMC should probably be preferred to chitosan in natural conditions (5 < pH < 8) since its impact on the permeation flux is less significant. Finally, ultrafiltration of an industrial discharge water has shown that the increase in metal ion rejection induced by the polymer addition is very low due to the competing phenomenon between the various ions present in the complex mixture.

Keywords: carboxymethyl cellulose, chitosan, heavy metals, nickel ion, polymer-assisted ultrafiltration

Procedia PDF Downloads 152

Authors: Andreas Aceranti, Riccardo Dossena, Marco Colorato, Simonetta Vernocchi

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By the term “limbic resonance,” we usually refer to a state of deep connection, both emotional and physiological, between people who, when in resonance, find their limbic systems in tune with one another. Limbic resonance is not only about sharing emotions but also physiological states. In fact, people in such resonance can influence each other’s heart rate, blood pressure, and breathing. Limbic resonance is fundamental for human beings to connect and create deep bonds among a certain group. It is fundamental for our social skills. A relationship between gifted and resonant subjects is perceived as feeling safe, living the relation like an isle of serenity where it is possible to recharge, to communicate without words, to understand each others without giving explanations, to strengthen the balance of each member of the group. Within the circle, self-esteem is consolidated and makes it stronger to face what is outside, others, and reality. The idea that gifted people who are together may be unfit for the world does not correspond to the truth. The circle made up of people with high cognitive potential characterized by a limbic resonance is, in general, experienced as a solid platform from which you can safely move away and where you can return to recover strength. We studied 8 adults (between 21 and 47 years old). All of them with IQ higher than 130. We monitored their brain waves frequency (alpha, beta, theta, gamma, delta) by means of biosensing tracker along with their physiological states (heart beat frequency, blood pressure, breathing frequency, pO2, pCO2) and some blood works only (5-HT, dopamine, catecholamines, cortisol). The subjects of the study were asked to adhere to a protocol involving bonding activities (such as team building activities), role plays, meditation sessions, and group therapy. All these activities were carried out together. We observed that after about 4 months of activities, their brain waves frequencies tended to tune quicker and quicker. After 9 months, the bond among them was so important that they could “sense” each other inner states and sometimes also guess each others’ thoughts. According to our findings, it may be hypothesized that large synchronized outbursts of cortex neurons produces not only brain waves but also electromagnetic fields that may be able to influence the cortical neurons’ activity of other people’s brain by inducing action potentials in large groups of neurons and this is reasonably conceivable to be able to transmit information such as different emotions and cognition cues to the other’s brain. We also believe that upcoming research should focus on clarifying the role of brain magnetic particles in brain-to-brain communication. We also believe that further investigations should be carried out on the presence and role of cryptochromes to evaluate their potential roles in direct brain-to-brain communication.

Keywords: limbic resonance, psychotherapy, brain waves, emotion regulation, giftedness

Procedia PDF Downloads 76

Authors: Nadine Maier, Martin Mensinger, Enea Tallushi

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In general, today, two types of launching bearings are used in the construction of large steel and steel concrete composite bridges. These are sliding rockers and systems with hydraulic bearings. The advantages and disadvantages of the respective systems are under discussion. During incremental launching, the center of the webs of the superstructure is not perfectly in line with the center of the launching bearings due to unavoidable tolerances, which may have an influence on the buckling behavior of the web plates. These imperfections are not considered in the current design against plate buckling, according to DIN EN 1993-1-5. It is therefore investigated whether the design rules have to take into account any eccentricities which occur during incremental launching and also if this depends on the respective launching bearing. Therefore, at the Technical University Munich, large-scale buckling tests were carried out on longitudinally stiffened plates under biaxial stresses with the two different types of launching bearings and eccentric load introduction. Based on the experimental results, a numerical model was validated. Currently, we are evaluating different parameters for both types of launching bearings, such as load introduction length, load eccentricity, the distance between longitudinal stiffeners, the position of the rotation point of the spherical bearing, which are used within the hydraulic bearings, web, and flange thickness and imperfections. The imperfection depends on the geometry of the buckling field and whether local or global buckling occurs. This and also the size of the meshing is taken into account in the numerical calculations of the parametric study. As a geometric imperfection, the scaled first buckling mode is applied. A bilinear material curve is used so that a GMNIA analysis is performed to determine the load capacity. Stresses and displacements are evaluated in different directions, and specific stress ratios are determined at the critical points of the plate at the time of the converging load step. To evaluate the load introduction of the transverse load, the transverse stress concentration is plotted on a defined longitudinal section on the web. In the same way, the rotation of the flange is evaluated in order to show the influence of the different degrees of freedom of the launching bearings under eccentric load introduction and to be able to make an assessment for the case, which is relevant in practice. The input and the output are automatized and depend on the given parameters. Thus we are able to adapt our model to different geometric dimensions and load conditions. The programming is done with the help of APDL and a Python code. This allows us to evaluate and compare more parameters faster. Input and output errors are also avoided. It is, therefore, possible to evaluate a large spectrum of parameters in a short time, which allows a practical evaluation of different parameters for buckling behavior. This paper presents the results of the tests as well as the validation and parameterization of the numerical model and shows the first influences on the buckling behavior under eccentric and multi-axial load introduction.

Keywords: buckling behavior, eccentric load introduction, incremental launching, large scale buckling tests, multi axial stress states, parametric numerical modelling

Procedia PDF Downloads 101

Authors: Catarina Bento, Ana Carolina Gonçalves, Fábio Jesus, Luís Rodrigues Silva

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Increasing evidence suggests that a diet rich in fruits and vegetables plays important roles in the prevention of chronic diseases, such as heart disease, cancer, stroke, diabetes, Alzheimer’s disease, among others. Fruits and vegetables gained prominence due their richness in bioactive compounds, being the focus of many studies due to their biological properties acting as health promoters. Prunus avium Linnaeus (L.), commonly known as sweet cherry has been the centre of attention due to its health benefits, and has been highly studied. In Portugal, most of the cherry production comes from the Fundão region. The Saco is one of the most important cultivar produced in this region, attributed with geographical protection. In this work, we prepared 3 extracts through solid-phase extraction (SPE): a whole extract, fraction I (non-coloured phenolics) and fraction II (coloured phenolics). The three extracts were used to determine the phenolic profile of Saco cultivar by liquid chromatography with diode array detection (LC-DAD) technique. This was followed by the evaluation of their biological potential, testing the extracts’ capacity to scavenge free-radicals (DPPH•, nitric oxide (•NO) and superoxide radical (O2●-)) and to inhibit α-glucosidase enzyme of all extracts. Additionally, we evaluated, for the first time, the protective effects against peroxyl radical (ROO•)-induced hemoglobin oxidation and hemolysis in human erythrocytes. A total of 16 non-coloured phenolics were detected, 3-O-caffeoylquinic and ρ-coumaroylquinic acids were the main ones, and 6 anthocyanins were found, among which cyanidin-3-O-rutinoside represented the majority. In respect to antioxidant activity, Saco showed great antioxidant potential in a concentration-dependent manner, demonstrated through the DPPH•,•NO and O2●-radicals, and greater ability to inhibit the α-glucosidase enzyme in comparison to the regular drug acarbose used to treat diabetes. Additionally, Saco proved to be effective to protect erythrocytes against oxidative damage in a concentration-dependent manner against hemoglobin oxidation and hemolysis. Our work demonstrated that Saco cultivar is an excellent source of phenolic compounds which are natural antioxidants that easily capture reactive species, such as ROO• before they can attack the erythrocytes’ membrane. In a general way, the whole extract showed the best efficiency, most likely due to a synergetic interaction between the different compounds. Finally, comparing the two separate fractions, the coloured fraction showed the most activity in all the assays, proving to be the biggest contributor of Saco cherries’ biological activity.

Keywords: biological potential, coloured phenolics, non-coloured phenolics, sweet cherry

Procedia PDF Downloads 238

Authors: Barbora Svechova, Monika Licbinska

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Geochemical modeling of mineralogical changes of various materials in contact with an aqueous solution is an important tool for predicting the processes and development of given materials at the site. The modeling focused on the mutual interaction of groundwater at the contact with the rock mass and its subsequent influence on concrete structures. The studied locality is located in Slovakia in the area of the Liptov Basin, which is a significant inter-mountain lowland, which is bordered on the north and south by the core mountains belt of the Tatras, where in the center the crystalline rises to the surface accompanied by Mesozoic cover. Groundwater in the area is bound to structures with complicated geological structures. From the hydrogeological point of view, it is an environment with a crack-fracture character. The area is characterized by a shallow surface circulation of groundwater without a significant collector structure, and from a chemical point of view, groundwater in the area has been classified as calcium bicarbonate with a high content of CO2 and SO4 ions. According to the European standard EN 206-1, these are waters with medium aggression towards the concrete. Three rock samples were taken from the area. Based on petrographic and mineralogical research, they were evaluated as calcareous shale, micritic limestone and crystalline shale. These three rock samples were placed in demineralized water for one month and the change in the chemical composition of the water was monitored. During the solution-rock interaction there was an increase in the concentrations of all major ions, except nitrates. There was an increase in concentration after a week, but at the end of the experiment, the concentration was lower than the initial value. Another experiment was the interaction of groundwater from the studied locality with a concrete structure. The concrete sample was also left in the water for 1 month. The results of the experiment confirmed the assumption of a reduction in the concentrations of calcium and bicarbonate ions in water due to the precipitation of amorphous forms of CaCO3 on the surface of the sample.Vice versa, it was surprising to increase the concentration of sulphates, sodium, iron and aluminum due to the leaching of concrete. Chemical analyzes from these experiments were performed in the PHREEQc program, which calculated the probability of the formation of amorphous forms of minerals. From the results of chemical analyses and hydrochemical modeling of water collected in situ and water from experiments, it was found: groundwater at the site is unsaturated and shows moderate aggression towards reinforced concrete structures according to EN 206-1a, which will affect the homogeneity and integrity of concrete structures; from the rocks in the given area, Ca, Na, Fe, HCO3 and SO4. Unsaturated waters will dissolve everything as soon as they come into contact with the solid matrix. The speed of this process then depends on the physicochemical parameters of the environment (T, ORP, p, n, water retention time in the environment, etc.).

Keywords: geochemical modeling, concrete , dissolution , PHREEQc

Procedia PDF Downloads 184

Authors: Amany Abdelrazek

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Fashion is considered the main feature of modern and postmodern capitalist and consumerist society. Consumer historians maintain that fashion, namely, a sector of people embracing a prevailing clothing style for a short period, started during the Middle Ages but gained popularity later. It symbolised the transition from a medieval society with its solid fixed religious values into a modern society with its secular consumer dynamic culture. Renaissance society was a modern secular society concerning its preoccupation with daily life and changing circumstances. Yet, the late 18th-century industrial revolution revolutionised thought and ideology in Europe. The Industrial Revolution reinforced the Western belief in rationality and strengthened the position of science. In such a rational Western society, modernity, with its new ideas, came to challenge the whole idea of old fixed norms, reflecting the modern secular, rational culture and renouncing the medieval pious consumer. In modern society, supported by the industrial revolution and mass production, fashion encouraged broader sectors of society to integrate into fashion reserved for the aristocracy and royal courts. Moreover, the fashion project emphasizes the human body and its beauty, contradicting Judeo-Christian culture, which tends to abhor and criticize interest in sensuality and hedonism. In mainstream Western discourse, fashionable dress differentiates between emancipated stylish consumerist secular modern female and the assumed oppressed traditional modest religious female. Opposing this discourse, I look at the controversy over what has been called "Islamic fashion" that started during the 1980s and continued to gain popularity in contemporary Egyptian society. I discuss the challenges of being a fashionable and Muslim practicing female in light of two prominent models for female "Islamic fashion" in postcolonial Egypt; Jasmin Mohshen, the first hijabi model in Egypt and Manal Rostom, the first Muslim woman to represent the Nike campaign in the Middle East. The research employs fashion and postcolonial theories to rethink current Muslim women's position on women's emancipation, Western modernity and practising faith in postcolonial Egypt. The paper argues that Muslim women's current innovative and fashionable dress can work as a counter-discourse to the Orientalist and exclusive representation of non-Western Muslim culture as an inherently inert timeless culture. Furthermore, "Islamic" fashionable dress as an aesthetic medium for expressing ideas and convictions in contemporary Egypt interrogates the claim of universal secular modernity and Western fashion theorists' reluctance to consider Islamic fashion as fashion.

Keywords: fashion, muslim women, modernity, secularism

Procedia PDF Downloads 113

Authors: Anastasios Georgoulas, Manolia Andredaki, Marco Marengo

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The present paper investigates the hydrodynamics and heat transfer characteristics of slug-plug flows under saturated flow boiling conditions within circular micro-channels. Numerical simulations are carried out, using an enhanced version of the open-source CFD-based solver ‘interFoam’ of OpenFOAM CFD Toolbox. The proposed user-defined solver is based in the Volume Of Fluid (VOF) method for interface advection, and the mentioned enhancements include the implementation of a smoothing process for spurious current reduction, the coupling with heat transfer and phase change as well as the incorporation of conjugate heat transfer to account for transient solid conduction. In all of the considered cases in the present paper, a single phase simulation is initially conducted until a quasi-steady state is reached with respect to the hydrodynamic and thermal boundary layer development. Then, a predefined and constant frequency of successive vapour bubbles is patched upstream at a certain distance from the channel inlet. The proposed numerical simulation set-up can capture the main hydrodynamic and heat transfer characteristics of slug-plug flow regimes within circular micro-channels. In more detail, the present investigation is focused on exploring the interaction between subsequent vapour slugs with respect to their generation frequency, the hydrodynamic characteristics of the liquid film between the generated vapour slugs and the channel wall as well as of the liquid plug between two subsequent vapour slugs. The proposed investigation is carried out for the 3 different working fluids and three different values of applied heat flux in the heated part of the considered microchannel. The post-processing and analysis of the results indicate that the dynamics of the evolving bubbles in each case are influenced by both the upstream and downstream bubbles in the generated sequence. In each case a slip velocity between the vapour bubbles and the liquid slugs is evident. In most cases interfacial waves appear close to the bubble tail that significantly reduce the liquid film thickness. Finally, in accordance with previous investigations vortices that are identified in the liquid slugs between two subsequent vapour bubbles can significantly enhance the convection heat transfer between the liquid regions and the heated channel walls. The overall results of the present investigation can be used to enhance the present understanding by providing better insight of the complex, underpinned heat transfer mechanisms in saturated boiling within micro-channels in the slug-plug flow regime.

Keywords: slug-plug flow regime, micro-channels, VOF method, OpenFOAM

Procedia PDF Downloads 254

Authors: Ravi Chaturvedi, Ghanshyam Beniwal

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Without going much into the detail of long history of Sufism in the world and the etymological definition of the word ‘Sufi’, it will be sufficient to underline that the concept of Sufism was to focus the mystic power on the spiritual dimension of Islam with a view-shielding the believers from the outwardly and unrealistic dogma of the faith. Sufis adopted rather a liberal view in propagating the religious order of Islam suitable to the cultural and social environment of the land. It is, in fact, a mission of higher religious order of any faith, which disdains strife and conflict in any form. The joy of self-realization being the essence of religion is experienced after a long spiritual practice. India had Sufi and Bhakti (devotion) traditions in Islam and Hinduism, respectively. Both Sufism and Bhakti traditions were based on respect for different religions. The poorer and lower caste Hindus and Muslims were greatly influenced by these traditions. Unlike Ulemas and Brahmans, the Sufi and Bhakti saints were highly tolerant and open to the truth in other faiths. They never adopted sectarian attitudes and were never involved in power struggles. They kept away from power structures. Sufism is integrated with the Indian cinema since its initial days. In the earliest Bollywood movies, Sufism was represented in the form of qawwali which made its way from dargahs (shrines). Mixing it with pop influences, Hindi movies began using Sufi music in a big way only in the current decade. However, of late, songs with Sufi influences have become de rigueur in almost every film being released these days, irrespective of the genre, whether it is a romantic Gangster or a cerebral Corporate. 'Sufi is in the DNA of the Indian sub-continent', according to several contemporary filmmakers, critics, and spectators.The inherent theatricality motivates the performer of the 'Sufi' rituals for a dramatic behavior. The theatrical force of these stages of Sufi practice is so powerful that even the spectator cannot resist himself from being moved. In a multi-cultural country like India, the mediating streams have acquired a multi-layered importance in recent history. The second half of Indian post-colonial era has witnessed a regular chain of some conflicting religio-political waves arising from various sectarian camps in the country, which have compelled the counter forces to activate for keeping the spirit of composite cultural ethos alive. The study has revealed that the Sufi practice methodology is also being adapted for inclusion of spirituality in life at par to Yoga practice. This paper, a part of research study, is an attempt to establish that the Sufism in Indian cinema is one such mediating voice which is very active and alive throughout the length and width of the country continuously bridging the gap between various religious and social factions, and have a significant role to play in future as well.

Keywords: Indian cinema, mediating voice, Sufi, yoga practice

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Authors: Małgorzata Golonka, Jadwiga Laska

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Self-healing polymers are one of the most investigated groups of smart materials. As materials engineering has recently focused on the design, production and research of modern materials and future technologies, researchers are looking for innovations in structural, construction and coating materials. Based on available scientific articles, it can be concluded that most of the research focuses on the self-healing of cement, concrete, asphalt and anticorrosion resin coatings. In our study, a method of obtaining and testing the properties of several types of microcapsules for use in self-healing polymer materials was developed. A method to obtain microcapsules exhibiting various mechanical properties, especially compressive strength was developed. The effect was achieved by using various polymer materials to build the shell: urea-formaldehyde resin (UFR), melamine-formaldehyde resin (MFR), melamine-urea-formaldehyde resin (MUFR). Dicyclopentadiene (DCPD) was used as the core material due to the possibility of its polymerization according to the ring-opening olefin metathesis (ROMP) mechanism in the presence of a solid Grubbs catalyst showing relatively high chemical and thermal stability. The ROMP of dicyclopentadiene leads to a polymer with high impact strength, high thermal resistance, good adhesion to other materials and good chemical and environmental resistance, so it is potentially a very promising candidate for the self-healing of materials. The capsules were obtained by condensation polymerization of formaldehyde with urea, melamine or copolymerization with urea and melamine in situ in water dispersion, with different molar ratios of formaldehyde, urea and melamine. The fineness of the organic phase dispersed in water, and consequently the size of the microcapsules, was regulated by the stirring speed. In all cases, to establish such synthesis conditions as to obtain capsules with appropriate mechanical strength. The microcapsules were characterized by determining the diameters and their distribution and measuring the shell thickness using digital optical microscopy and scanning electron microscopy, as well as confirming the presence of the active substance in the core by FTIR and SEM. Compression tests were performed to determine mechanical strength of the microcapsules. The highest repeatability of microcapsule properties was obtained for UFR resin, while the MFR resin had the best mechanical properties. The encapsulation efficiency of MFR was much lower compared to UFR, though. Therefore, capsules with a MUFR shell may be the optimal solution. The chemical reaction between the active substance present in the capsule core and the catalyst placed outside the capsules was confirmed by FTIR spectroscopy. The obtained autonomous repair systems (microcapsules + catalyst) were introduced into polyethylene in the extrusion process and tested for the self-repair of the material.

Keywords: autonomic self-healing system, dicyclopentadiene, melamine-urea-formaldehyde resin, microcapsules, thermoplastic materials

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Authors: Mia Bahar, Özlem Bozkurt

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Obsessive-compulsive disorder (OCD) is a typical, persistent, and long-lasting mental health condition in which a person experiences uncontrollable, recurrent thoughts (or "obsessions") and/or activities (or "compulsions") that they feel compelled to engage in repeatedly. Obsessive-compulsive disorder is both underdiagnosed and undertreated. It frequently manifests in a variety of medical settings and is persistent, expensive, and burdensome. Obsessive-compulsive neurosis was long believed to be a condition that offered valuable insight into the inner workings of the unconscious mind. Obsessive-compulsive disorder is now recognized as a prime example of a neuropsychiatric condition susceptible to particular pharmacotherapeutic and psychotherapy therapies and mediated by pathology in particular neural circuits. An obsessive-compulsive disorder which is called OCD, usually has two components, one cognitive and the other behavioral, although either can occur alone. Obsessions are often repetitive and intrusive thoughts that invade consciousness. These obsessions are incredibly hard to control or dismiss. People who have OCD often engage in rituals to reduce anxiety associated with intrusive thoughts. Once the ritual is formed, the person may feel extreme relief and be free from anxiety until the thoughts of contamination intrude once again. These thoughts are strengthened through a manifestation of negative reinforcement because they allow the person to avoid anxiety and obscurity. These thoughts are described as autogenous, meaning they most likely come from nowhere. These unwelcome thoughts are related to actions which we can describe as Thought Action Fusion. The thought becomes equated with an action, such as if they refuse to perform the ritual, something bad might happen, and so people perform the ritual to escape the intrusive thought. In almost all cases of OCD, the person's life gets extremely disturbed by compulsions and obsessions. Studies show OCD is an estimated 1.1% prevalence, making it a challenging issue with high co-morbidities with other issues like depressive episodes, panic disorders, and specific phobias. The first to reveal brain anomalies in OCD were numerous CT investigations, although the results were inconsistent. A few studies have focused on the orbitofrontal cortex (OFC), anterior cingulate gyrus (AC), and thalamus, structures also implicated in the pathophysiology of OCD by functional neuroimaging studies, but few have found consistent results. However, some studies have found abnormalities in the basal ganglion. There have also been some discussions that OCD might be genetic. OCD has been linked to families in studies of family aggregation, and findings from twin studies show that this relationship is somewhat influenced by genetic variables. Some Research has shown that OCD is a heritable, polygenic condition that can result from de novo harmful mutations as well as common and unusual variants. Numerous studies have also presented solid evidence in favor of a significant additive genetic component to OCD risk, with distinct OCD symptom dimensions showing both common and individual genetic risks.

Keywords: compulsions, obsessions, neuropsychiatric, genetic

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Authors: Sunil P. Lonkar, Vishnu V. Pillai, Saeed Alhassan

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Design and development of highly efficient, inexpensive, and long-term stable earth-abundant electrocatalysts hold tremendous promise for hydrogen evolution reaction (HER) in water electrolysis. The 2D transition metal dichalcogenides, especially molybdenum disulfide attracted a great deal of interests due to its high electrocatalytic activity. However, due to its poor electrical conductivity and limited exposed active sites, the performance of these catalysts is limited. In this context, a facile and scalable synthesis method for fabrication nanostructured electrocatalysts composed 3D graphene porous aerogels supported with MoS₂ and WS₂ is highly desired. Here we developed a highly active and stable electrocatalyst catalyst for the HER by growing it into a 3D porous architecture on conducting graphene. The resulting nanohybrids were thoroughly investigated by means of several characterization techniques to understand structure and properties. Moreover, the HER performance of these 3D catalysts is expected to greatly improve in compared to other, well-known catalysts which mainly benefits from the improved electrical conductivity of the by graphene and porous structures of the support. This technologically scalable process can afford efficient electrocatalysts for hydrogen evolution reactions (HER) and hydrodesulfurization catalysts for sulfur-rich petroleum fuels. Owing to the lower cost and higher performance, the resulting materials holds high potential for various energy and catalysis applications. In typical hydrothermal method, sonicated GO aqueous dispersion (5 mg mL⁻¹) was mixed with ammonium tetrathiomolybdate (ATTM) and tungsten molybdate was treated in a sealed Teflon autoclave at 200 ◦C for 4h. After cooling, a black solid macroporous hydrogel was recovered washed under running de-ionized water to remove any by products and metal ions. The obtained hydrogels were then freeze-dried for 24 h and was further subjected to thermal annealing driven crystallization at 600 ◦C for 2h to ensure complete thermal reduction of RGO into graphene and formation of highly crystalline MoS₂ and WoS₂ phases. The resulting 3D nanohybrids were characterized to understand the structure and properties. The SEM-EDS clearly reveals the formation of highly porous material with a uniform distribution of MoS₂ and WS₂ phases. In conclusion, a novice strategy for fabrication of 3D nanostructured MoS₂-WS₂/graphene is presented. The characterizations revealed that the in-situ formed promoters uniformly dispersed on to few layered MoS₂¬-WS₂ nanosheets that are well-supported on graphene surface. The resulting 3D hybrids hold high promise as potential electrocatalyst and hydrodesulfurization catalyst.

Keywords: electrocatalysts, graphene, transition metal chalcogenide, 3D assembly

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Authors: Bastien Sanglard, Lou Magnat, Ligia Barna, Julian Carrey, Sébastien Lachaize

Abstract:

Cooking is a primary need for humans, several techniques being used around the globe based on different sources of energy: electricity, solid fuel (wood, coal...), fuel or liquefied petroleum gas. However, all of them leads to direct or indirect greenhouse gas emissions and sometimes health damage in household. Therefore, the solar concentrated power represent a great option to lower the damages because of a cleaner using phase. Nevertheless, the construction phase of the solar cooker still requires primary energy and materials, which leads to environmental impacts. The aims of this work is to analyse the ecological impacts of a commercialaluminium parabola and to compare it with other means of cooking, taking the boiling of 2 litres of water three times a day during 40 years as the functional unit. Life cycle assessment was performed using the software Umberto and the EcoInvent database. Calculations were realized over more than 13 criteria using two methods: the international panel on climate change method and the ReCiPe method. For the reflector itself, different aluminium provenances were compared, as well as the use of recycled aluminium. For the structure, aluminium was compared to iron (primary and recycled) and wood. Results show that climate impacts of the studied parabola was 0.0353 kgCO2eq/kWh when built with Chinese aluminium and can be reduced by 4 using aluminium from Canada. Assessment also showed that using 32% of recycled aluminium would reduce the impact by 1.33 and 1.43 compared to the use of primary Canadian aluminium and primary Chinese aluminium, respectively. The exclusive use of recycled aluminium lower the impact by 17. Besides, the use of iron (recycled or primary) or wood for the structure supporting the reflector significantly lowers the impact. The impact categories of the ReCiPe method show that the parabola made from Chinese aluminium has the heaviest impact - except for metal resource depletion - compared to aluminium from Canada, recycled aluminium or iron. Impact of solar cooking was then compared to gas stove and induction. The gas stove model was a cast iron tripod that supports the cooking pot, and the induction plate was as well a single spot plate. Results show the parabolic solar cooker has the lowest ecological impact over the 13 criteria of the ReCiPe method and over the global warming potential compared to the two other technologies. The climate impact of gas cooking is 0.628kgCO2/kWh when used with natural gas and 0.723 kgCO2/kWh when used with a bottle of gas. In each case, the main part of emissions came from gas burning. Induction cooking has a global warming potential of 0.12 kgCO2eq/kWh with the electricity mix of France, 96.3% of the impact being due to electricity production. Therefore, the electricity mix is a key factor for this impact: for instance, with the electricity mix of Germany and Poland, impacts are 0.81kgCO2eq/kWh and 1.39 kgCO2eq/kWh, respectively. Therefore, the parabolic solar cooker has a real ecological advantages compared to both gas stove and induction plate.

Keywords: life cycle assessement, solar concentration, cooking, sustainability

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Authors: Anna Makuch, Grzegorz Kokot, Konstanty Skalski, Jakub Banczorowski

Abstract:

Cancellous bone is a porous composite of a hierarchical structure and anisotropic properties. The biological tissue is considered to be a viscoelastic material, but many studies based on a nanoindentation method have focused on their elasticity and microhardness. However, the response of many organic materials depends not only on the load magnitude, but also on its duration and time course. Depth Sensing Indentation (DSI) technique has been used for examination of creep in polymers, metals and composites. In the indentation tests on biological samples, the mechanical properties are most frequently determined for animal tissues (of an ox, a monkey, a pig, a rat, a mouse, a bovine). However, there are rare reports of studies of the bone viscoelastic properties on microstructural level. Various rheological models were used to describe the viscoelastic behaviours of bone, identified in the indentation process (e. g Burgers model, linear model, two-dashpot Kelvin model, Maxwell-Voigt model). The goal of the study was to determine the influence of creep effect on the mechanical properties of human cancellous bone in indentation tests. The aim of this research was also the assessment of the material properties of bone structures, having in mind the energy aspects of the curve (penetrator loading-depth) obtained in the loading/unloading cycle. There was considered how the different holding times affected the results within trabecular bone.As a result, indentation creep (CIT), hardness (HM, HIT, HV) and elasticity are obtained. Human trabecular bone samples (n=21; mean age 63±15yrs) from the femoral heads replaced during hip alloplasty were removed and drained from alcohol of 1h before the experiment. The indentation process was conducted using CSM Microhardness Tester equipped with Vickers indenter. Each sample was indented 35 times (7 times for 5 different hold times: t1=0.1s, t2=1s, t3=10s, t4=100s and t5=1000s). The indenter was advanced at a rate of 10mN/s to 500mN. There was used Oliver-Pharr method in calculation process. The increase of hold time is associated with the decrease of hardness parameters (HIT(t1)=418±34 MPa, HIT(t2)=390±50 MPa, HIT(t3)= 313±54 MPa, HIT(t4)=305±54 MPa, HIT(t5)=276±90 MPa) and elasticity (EIT(t1)=7.7±1.2 GPa, EIT(t2)=8.0±1.5 GPa, EIT(t3)=7.0±0.9 GPa, EIT(t4)=7.2±0.9 GPa, EIT(t5)=6.2±1.8 GPa) as well as with the increase of the elastic (Welastic(t1)=4.11∙10-7±4.2∙10-8Nm, Welastic(t2)= 4.12∙10-7±6.4∙10-8 Nm, Welastic(t3)=4.71∙10-7±6.0∙10-9 Nm, Welastic(t4)= 4.33∙10-7±5.5∙10-9Nm, Welastic(t5)=5.11∙10-7±7.4∙10-8Nm) and inelastic (Winelastic(t1)=1.05∙10-6±1.2∙10-7 Nm, Winelastic(t2) =1.07∙10-6±7.6∙10-8 Nm, Winelastic(t3)=1.26∙10-6±1.9∙10-7Nm, Winelastic(t4)=1.56∙10-6± 1.9∙10-7 Nm, Winelastic(t5)=1.67∙10-6±2.6∙10-7)) reaction of materials. The indentation creep increased logarithmically (R2=0.901) with increasing hold time: CIT(t1) = 0.08±0.01%, CIT(t2) = 0.7±0.1%, CIT(t3) = 3.7±0.3%, CIT(t4) = 12.2±1.5%, CIT(t5) = 13.5±3.8%. The pronounced impact of creep effect on the mechanical properties of human cancellous bone was observed in experimental studies. While the description elastic-inelastic, and thus the Oliver-Pharr method for data analysis, may apply in few limited cases, most biological tissues do not exhibit elastic-inelastic indentation responses. Viscoelastic properties of tissues may play a significant role in remodelling. The aspect is still under an analysis and numerical simulations. Acknowledgements: The presented results are part of the research project founded by National Science Centre (NCN), Poland, no.2014/15/B/ST7/03244.

Keywords: bone, creep, indentation, mechanical properties

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