Simulations of spacing of localized zones in reinforced concrete beams using elasto-plasticity and damage mechanics with non-local softening

I. Marzec,J. Bobinski,J. Tejchman 한국계산역학회 2007 Computers and Concrete, An International Journal Vol.4 No.5

The paper presents quasi-static plane strain FE-simulations of strain localization in reinforced concrete beams without stirrups. The material was modeled with two different isotropic continuum crack models: an elasto-plastic and a damage one. In case of elasto-plasticity, linear Drucker-Prager criterion with a non-associated flow rule was defined in the compressive regime and a Rankine criterion with an associated flow rule was adopted in the tensile regime. In the case of a damage model, the degradation of the material due to micro-cracking was described with a single scalar damage parameter. To ensure the mesh-independence and to capture size effects, both criteria were enhanced in a softening regime by nonlocal terms. Thus, a characteristic length of micro-structure was included. The effect of a characteristic length, reinforcement ratio, bond-slip stiffness, fracture energy and beam size on strain localization was investigated. The numerical results with reinforced concrete beams were quantitatively compared with corresponding laboratory tests by Walraven (1978).

Computational simulations of concrete behaviour under dynamic conditions using elasto-visco-plastic model with non-local softening

Ireneusz Marzec,Jacek Tejchman,Andrzej Winnicki 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.15 No.4

The paper presents results of FE simulations of the strain-rate sensitive concrete beha515viour under dynamic loading at the macroscopic level. To take the loading velocity effect into account, viscosity, stress modifications and inertial effects were included into a rate-independent elasto-plastic formulation. In addition, a decrease of the material stiffness was considered for a very high loading velocity to simulate fragmentation. In order to ensure the mesh-independence and to properly reproduce strain localization in the entire range of loading velocities, a constitutive formulation was enhanced by a characteristic length of micro-structure using a non-local theory. Numerical results were compared with corresponding laboratory tests and available analytical formulae.

Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches

Ireneusz Marzec,Łukasz Skarżyńsk,Jerzy Bobiński,Jacek Tejchman 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.5

The paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack and isotropic damage model were applied. Finally, an elasto-plastic-damage model was used. To ensure mesh-independent FE results, to describe strain localization in concrete and to capture a deterministic size effect, all models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. Bond-slip between concrete and reinforcement was considered. The numerical results were directly compared with the corresponding laboratory tests performed by Walraven and Lehwalter (1994). The advantages and disadvantages of enhanced models to model the reinforced concrete behaviour were outlined.

Characterization and properties of new color-tunable hybrid pigments based on layered double hydroxides (LDH) and 1,2-dihydroxyanthraquinone dye

Anna Marzec,Bolesław Szadkowski,Jacek Rogowski,Waldemar Maniukiewicz,Marcin Kozanecki,Dariusz Moszy nski,Marian Zaborski 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

In this paper a novel, simple method for synthesis of lake pigments based on 1,2-dihydroxyanthra-quinone dye and LDH carbonates was proposed. LDHs were modified with 1,2-dihydroxyanthraquinone,transforming the soluble dye into a new kind of hybrid lake. In result, the solvent resistance andphotostability of the chromophore were improved, which may be attributed to strong dye–LDHinteractions. TOF-SIMS technique was used for thefirst time to confirm the role of C14H7O4Mg+ andC14H6O5Al ions in the formation of the hybrids. Alizarin lakes have been recognized as a new class ofcolorants which demonstrated good color characteristics and chemical stability.

The Effects of Insulin-like Growth Factor-I(IGF-I) on Osteoblastic Cells : Role of Voltage-Activated Calcium Channels

Ma, Gang,Marzec, Nancy,Dziak, Rosemary Korean Academy of Oral Biology and the UCLA Dental 2001 International Journal of Oral Biology Vol.26 No.1

The goal of this present study was to investigate the effects of insulin-like growth factor (IGF-I) on osteoblastic cell proliferation, and the possible involvement of the alpha 1 subunit of L-type voltage activated calcium channels (L-VACC) in the regulation of these effects. In rat calvarial osteoblastic cells, incubation with 100 nM IGF-I for 24 hours significantly increased cell proliferation. The IGF-I-induced increase in cell proliferation was inhibited by verapamil (10-100 μM), a blocker of L-VACCs. In order to further investigate which isoform(s) of L-VACCs is involved in the effect of IGF-I, antisense oligodeoxynucleotides (ODNs) specific for alpha 1S (skeletal), alpha 1C (cardiac) or alpha 1D (neuroendocrine) of L-VACC were used to inhibit the expression of the different isoforms. The results showed that the proliferative response to IGF-I was significantly inhibited by the antisense ODN directed to the alpha 1C of L-VACC (decrease by 28%, P<0.05, ANOVA), but not by sense to alpha 1C or antisense/sense ODNs to alpha 1S and alpha 1D. The data suggest that the cardiac isoform of the L-VACC is at least partially responsible for IGF-I-induced increases in rat osteoblastic cell proliferation.

Dried strawberries as a high nutritional value fruit snack

Kowalska, Jolanta,Kowalska, Hanna,Marzec, Agata,Brzezinski, Tomasz,Samborska, Kinga,Lenart, Andrzej Korean Society of Food Science and Technology 2018 Food Science and Biotechnology Vol.27 No.3

The purpose of this study was to determine the possibility of using a chokeberry juice concentrate as a component of osmotic solution and convection-microwave-vacuum drying applying to obtain dried pro-health-promoting strawberries. The research material was Honeoye strawberries, which were dehydrated in sucrose and sucrose with chokeberry juice concentrate addition, and then subjected to microwave-convection-vacuum or freeze-drying. Analyses were conducted to determine the influence of the applied processes on vitamin C content, total polyphenols, antioxidant activity, and sensory properties in dried fruit. Study results confirmed the possibility of using a chokeberry juice concentrate as a component of the osmotic solution, especially with regard to polyphenolics content and antioxidant activity. In addition, convection-microwave-vacuum drying was shown to be a promising technology for the production of dried strawberries, with high pro-health potential and acceptable sensory qualities.

Dried strawberries as a high nutritional value fruit snack

Jolanta Kowalska,Hanna Kowalska,Agata Marzec,Tomasz Brzezin´ ski,Kinga Samborska,Andrzej Lenart 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.3

The purpose of this study was to determine the possibility of using a chokeberry juice concentrate as a component of osmotic solution and convection-microwavevacuum drying applying to obtain dried pro-health-promoting strawberries. The research material was Honeoye strawberries, which were dehydrated in sucrose and sucrose with chokeberry juice concentrate addition, and then subjected to microwave-convection-vacuum or freezedrying. Analyses were conducted to determine the influence of the applied processes on vitamin C content, total polyphenols, antioxidant activity, and sensory properties in dried fruit. Study results confirmed the possibility of using a chokeberry juice concentrate as a component of the osmotic solution, especially with regard to polyphenolics content and antioxidant activity. In addition, convectionmicrowave- vacuum drying was shown to be a promising technology for the production of dried strawberries, with high pro-health potential and acceptable sensory qualities.

Experiments and numerical analyses for composite RC-EPS slabs

Ł. Skarżyński,J. Tejchman,I. Marzec 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.6

The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

Effect of crude fibre additives ARBOCEL and VITACEL on the physicochemical properties of granulated feed mixtures for broiler chickens

Urban Jakub,Michalczuk Monika,Batorska Martyna,Marzec Agata,Jaroszek Adriana,Bień Damian 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.2

Objective: The aim of the study was to evaluate the physicochemical properties (nutrient composition, pH, water content and activity, sorption properties) and mechanical properties (compression force and energy) of granulated feed mixtures with various inclusion levels of crude fibre concentrates ARBOCEL and VITACEL for broiler chickens, i.e. +0.0% (control group - group C), +0.3%, +0.8%, +1.0%, +1.2%. Methods: The feed mixtures were analyzed for their physicochemical properties (nutrient composition by near-infrared spectroscopy, pH with the use a CP-401 pH meter with an IJ-44C glass electrode, water content was determined with the drying method and activity was determined with the Aqua Lab Series 3, sorption properties was determined with the static method) and mechanical properties (compression force and energy with the use TAHD plus texture analyzer). The Guggenheim-Anderson-de Boer (GAB) model applied in the study correctly described the sorption properties of the analyzed feed mixtures in terms of water activity. Results: The fibre concentrate type affected the specific surface area of the adsorbent and equilibrium water content in the GAB monolayer (p≤0.05) (significantly statistical). The type and dose of the fibre concentrate influenced the dimensionless C and k parameters of the GAB model related to the properties of the monolayer and multilayers, respectively (p≤0.05). They also affected the pH value of the analyzed feed mixtures (p≤0.05). In addition, crude fibre type influenced water activity (p≤0.05) as well as compression energy (J) and compression force (N) (p≤0.001) (highly significantly statistical) of the feed mixtures. Conclusion: The physicochemical analyses of feed mixtures with various inclusion levels (0.3%, 0.8%, 1.0%, 1.2%) of crude fiber concentrates ARBOCEL or VITACEL demonstrated that both crude fiber types may be used in the feed industry as a feedstuff material to produce starter type mixtures for broiler chickens.

New natural organic–inorganic pH indicators: Synthesis and characterization of pro-ecological hybrid pigments based on anthraquinone dyes and mineral supports

Bolesław Szadkowski,Jacek Rogowski,Waldemar Maniukiewicz,Emmanuel Beyou,Anna Marzec 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

We present a strategy that leads to the formation of high-performance hybrid pigments made from naturalanthraquinone chromophores (alizarin, purpurin) and mineral supports (palygorskite (PAL), sepiolite(SEP), and hydroxyapatite (HAP)). Thanks to the mineral filler form features and the synergy between theorganic and inorganic components, the as-prepared hybrid pigments showed excellent thermal andchemical stability. The natural pigments exhibited strong pH-sensing activity, changing their color uponexposure to HCl and/or NH3 vapors. The PAL-based pigments were found to be the most effective pH indicators,showing pronounced color changes after 10 min of exposure to HCl (DE for PAL/A was 7.4). ToFSIMS,13C NMR and XPS techniques revealed interactions between the organic dyes and metal ions presentin the minerals. XPS spectroscopy was also used to examine the alterations in the structure of thehybrid colorants following exposure to acid vapors. The proposed pH sensors were successfully appliedto elastomer and thermoplastic elastomer matrices. The purpurin-based hybrid pigments exhibited significantlyreduced migration from the polymer (about six times lower concentration in ethanol after14 days). The results of this study pave a new way for the design, development, and application ofadvanced hybrid colorants with pH-sensing activity and improved stability.