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Cindy Astelia Ramadhan Suparman, Endah Purwanti, Prihartini Widiyanti
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 20-28;

Dengue Hemorrhagic Fever is a disease which is endemic in most districts / cities still becomes a public health problem in Indonesia. The awareness of people to the dengue viral infection and its symptoms are needed to decrease the fatality of this disease. The community need to be known the symptoms thereby they could intervened and prevent from falling in to worse condition. This study was conducted to design system which could diagnose the onset of the disease with 3 levels of possibilities namely Grade 1 Dengue Hemorrhagic Fever, Grade 2 Dengue Hemorrhagic Fever, and Non Dengue Hemorrhagic Fever. The system is build based on patient medical records of Dr. Wahidin Sudiro Husodo General Hospital, Mojokerto, East Java using the Naive Bayes method. The method of this study including several steps such as collecting data, preprocessing data, designing database, interface design, calculation and processing data, classification and analyzing data and evaluating application. Determining the results of the application diagnose requires posterior calculation which searches the highest values in three degrees as the results of the initial diagnose. The application as a device for an early diagnosis of dengue hemorrhagic fever has a high accuracy value of 97% out of the 30 tested data. The homogenization of the training data and the test data by sex and age can be considered in future research.
William Arthur,
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 29-36;

This paper proposes and presents the proof of concept for an improvised device adapted from the condom tamponade used for controlling atonic primary postpartum haemorrhage in resource-poor settings. The device has been designed to address the setbacks of the conventional condom tamponade. The setbacks of the condom tamponade were assessed. Using the systematic engineering design process, a device was designed to address the setbacks of the condom tamponade. The device comprises an inflation/deflation system, blood drainage system and clamping system. Results from testing show that for an inexperienced user, the device has quicker inflation (3.36 ± 1.70 minutes/ 500 ml) and faster set-up time (3.60 ± 1.50 minutes), as compared to the conventional condom tamponade. The clamping system of the device also ensures effective control of fluid dynamics and prevents backflow. The device, however, was not tested on human subjects to prove its efficacy for actual treatment of patients. The device also can be easily and quickly set-up and operated by frontline healthcare providers with limited expertise, in resource-poor settings. It has further been designed for safety (use of biocompatible materials and elimination of sharp edges for the parts expected to have direct contact with the uterus).
Mihaela Păpușa Vasiliu, Liliana Sachelarie, Laura Ecaterina Romila, Ardeshir Shardi, Carmen Stadoleanu, Daniela Ivona Tomita
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 75-81;

The dimensional stability of dental impression materials is one of the variables that contribute to the accuracy or to the inexactitude of dentures. The rheological properties of several dental impression materials were determined by amplitude and frequency sweep tests. Deformation, storage modulus G’, loss modulus G” and complex viscosity η*were studied for each sample. Moreover, the texture, the stability of the shape, the capacity of distribution on different surfaces and the stability to storage for a long period of time were investigated. All these samples, characterized by a gel structure with G’>G”, are suitable as impression materials. Irreversible hydro-colloids) may be used for different kind of impressions because of their fidelity and elasticity; they also present medium time elasticity and may be easily prepared.
Endang W. Bachtiar, Fatma S. Dewi, Ahmad Aulia Yusuf, Rahmi Ulfiana
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 94-100;

This is preliminary study in order to investigate the effect of dental pulp stem cells (DPSCs) on bone regeneration in an animal model. New Zealand rabbits were used as animal model. The critical defect was created in femoral bone and transplantation of DPSCs applied into bone defect. A colorimetric assay was used to detect ALP level in rabbit’s serum. Bone tissue regeneration was evaluated by histological analysis. In the 2nd week, the treated rabbit show increasing in the activity of ALP (157,925 μU) compared to control rabbit (155,361 μU). This increasing trend continues significantly in DPSCs rabbit (169.750 μU) compared to control rabbit (160.406) after 4 weeks. Histological evaluation revealed that the amount of bone lamellae and osteocytes were filled the defect area of DPSCs treated rabbit. Conclusions: Transplantation of DPSCs accelerating bone regeneration by raising ALP level and forming new bone tissue.
Ying Yue Zhang, , Justin Fernandez, Yao Dong Gu
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 1-9;

To determine the influence of the unstable sole structure on foot kinematics and provide theoretical basis for further application.12 healthy female subjects walked through a 10-meter experimental channel with normal speed wearing experimental shoes and control shoes respectively at the gait laboratory. Differences between the groups in triplanar motion of the forefoot, rearfoot and hallux during walking were evaluated using a three-dimensional motion analysis system incorporating with Oxford Foot Model (OFM). Compare to contrast group, participants wearing experimental shoes demonstrated greater peak forefoot dorsiflexion, forefoot supination and longer halluces plantar flexion time in support phase. Additionally, participants with unstable sole structure also demonstrated smaller peak forefoot plantarflexion, rearfoot dorsiflexion and range of joint motion in sagittal plane and frontal plane.. The difference mainly appeared in sagittal and frontal plane. With a stimulation of unstable, it may lead to the reinforcement of different flexion between middle and two ends of the foot model. The greater forefoot supination is infered that the unstable element structure may affect the forefoot motion on the frontal plane and has a control effect to strephexopodia people. The stimulation also will reflexes reduce the range of rearfoot motion in sagittal and frontal planes to control the gravity center of the body and keep a steady state in the process of walking.
P. Amaravathy, T.S. Sampath Kumar
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 57-67;

A simple chemical conversion coating was adopted to deposit zinc calcium phosphate (ZCP) coating and strontium doped ZCP (SZCP) coating on AZ31 magnesium alloy to induce biocompatibility and reduce the degradation rate. The surface morphology, chemical composition and functional groups of the coating were characterized by Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM-EDS), X-Ray Diffraction (XRD) studies and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy respectively. SZCP coating formed at 20 min deposition time produced crack free surface with a high degree of crystallinity with barrier property, which ultimately retards the dissolution of magnesium in Simulated Body Fluid (SBF). The corrosion resistance of AZ31 magnesium alloy was improved by SZCP coating as evident from hydrogen evolution test (HET). Cytotoxicity evaluation with L969 cells showed that Sr doped ZCP coatings showed less toxicity on resorbable magnesium alloys.
Abdelyamine Boukhobza, Mourad Brioua, Smail Benaicha, Kamel Fedaoui
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 68-74;

The aim of this paper is to examine a premature breakage of two compression plates for fixing broken bones with different patients for the period of their recovery. Each compression plate's breakage can induce grave consequences such as a new surgery, unexpected undesired complications and a prolonged healing time. The investigation of the compression plate breakage causes required an examination of the chemical composition and steel hardness, metallographic examination as well as that of the compression plate breakage surface by means of macroscopic and microscopic observations using microscope. On the origin of the results it can be established that the breakage was caused by high static load.
Harrison T. Pajovich, Alexandra M. Brown, Andrew M. Smith, Sara K. Hurley, Jessica R. Dorilio, Nicole M. Cutrone, Ipsita A. Banerjee
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 37-56;

In this work, for the first time, chlorogenic acid, a natural phytochemical, was conjugated to a lactoferrin derived antimicrobial peptide sequence RRWQWRMKKLG to develop a self-assembled template. To mimic the components of extracellular matrix, we then incorporated Type I Collagen, followed by a sequence of aggrecan peptide (ATEGQVRVNSIYQDKVSL) onto the self-assembled templates for potential applications in ligament tissue regeneration. Mechanical properties and surface roughness were studied and the scaffolds displayed a Young’s Modulus of 169 MP and an average roughness of 72 nm respectively. Thermal phase changes were studied by DSC analysis. Results showed short endothermic peaks due to water loss and an exothermic peak due to crystallization of the scaffold caused by rearrangement of the components. Biodegradability studies indicated a percent weight loss of 27.5 % over a period of 37 days. Furthermore, the scaffolds were found to adhere to fibroblasts, the main cellular component of ligament tissue. The scaffolds promoted cell proliferation and displayed actin stress fibers indicative of cell motility and attachment. Collagen and proteoglycan synthesis were also promoted, demonstrating increased expression and deposition of collagen and proteoglycans. Additionally, the scaffolds exhibited antimicrobial activity against Staphylococcus epidermis bacteria, which is beneficial for minimizing biofilm formation if potentially used as implants. Thus, we have developed a novel biocomposite that may open new avenues to enhance ligament tissue regeneration.
, Haniza Yazid, Wahida Kamaruddin
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 10-19;

Segmentation of blood vessels in the retinal is a crucial step in the diagnosis of eye diseases such as diabetic retinopathy and glaucoma. This paper presents a supervised method for automatic segmentation of blood vessels in retinal images. The proposed method based on a hybrid combination between Gray-Level and Moment Invariant techniques. There are four steps involved, whereas preprocessing, feature extraction, classification, and post-processing. In the preprocessing, three stages are performed include vessel central light reflex removal, background homogenization, and vessel enhancement. The 7-D vector feature extraction was performed to compute that compose of gray-level and moment invariants-based features for pixel representation. The decision tree is used for classification step that characterized the pixel based on vessels and non-vessels. The final step is the post-processing which will remove the small artifacts appears after classification process. The proposed method was compared to the Vascular Tree method and Morphological method. Based on the objective evaluation, the proposed method achieved (sensitivity = 98.589, specificity = 55.544 and accuracy = 96.197).
Yamina Chelahi Chikr, Benali Boutabout, Ali Merdji, Kheira Bouzouina
Journal of Biomimetics, Biomaterials and Biomedical Engineering, Volume 34, pp 82-93;

The purpose of this study was to develop a new three-dimensional model of an osseointegrated molar dental prosthesis and to carry out finite element analysis to evaluate stress distributions and intensities in the bone and in the components of dental prosthesis under three loads (corono-apical, distal-mesial and buccal-lingual) were applied to the top of the occlusal face of the prosthesis crown. The interfacial stresses were also determined inside and outside of the threading when the dental prosthesis system was subjected to one of three masticatory loads. All materials used in the models were considered to be isotropic, homogeneous and linearly elastic. The elastic properties, loads and constraints used in the model were taken from published data. In this study, the stress concentration occurred around the threaded dental implant neck. Thus, this area should be preserved clinically in order to maintain the bone–implant interface structurally and functionally.
, Viktor Kizinievič, Justinas Gargasas
Materials Science Forum, Volume 908, pp 118-122;

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.
Giedrius Girskas
Materials Science Forum, Volume 908, pp 71-75;

Durability is one of the main characteristics in the production of high-quality concrete paving blocks in the Baltic region climate zone. Concrete paving blocks are produced by means of vibropressing,dimensions: 198×98×80 mm. The article describes tests with concrete paving blocks, the top layer of which contains 5% of zeolite admixture obtained from waste of aluminum fluoride production by low-temperature synthesis.The durability of concrete paving blocks was tested according to abrasion resistance, tensile splitting strength, absorption and frost resistance. The test results revealed that 5% of zeolite admixture added to the top layer of concrete paving blocks reduce the absorption, increase the tensile splitting strength and decrease abrasion. The zeolite admixture used in concrete paving blocks reduces the scaling about 4 times after 28 freeze-thaw cycles when 3% NaCl is used as the freezing solution. The test results proved that synthetic zeolite obtained from aluminum fluoride by means of low temperature synthesis can be used as a supplementary cementitious material to increase the durability of concrete pavement elements.
Iveta Nováková,
Materials Science Forum, Volume 908, pp 164-170;

Use of high strength concrete (HSC) becoming inevitable in case of modern structures, which require application of advanced materials. High strength of concrete can be reached by higher dose of cement or addition of various kinds of fibres as a dispersed reinforcement. In practice are most commonly used steel, glass and polypropylene fibres, but basalt fibres are still under investigation. Basalt is highly resistance to aggressive chemicals and stable in high temperatures in comparison to other materials used for dispersed reinforcement. This study focuses on use of chopped basalt fibres in purpose to enhance properties of harden concrete. Six mixes with various dose of cement and chopped basalt fibres were designed for evaluation of properties of fresh and hardened concrete. As it was expected, chopped basalt fibres have negative influence on workability of fresh concrete but in comparison to other types of fibres the decrease is not that dramatic. Test results indicate increase of compressive strength after 28 days and even higher gain of strength after 90 days in case of mixes with addition of chopped basalt fibres. Reduction of strength due to exposure to 400 and 800 °C is also evaluated and in case of 400 °C temperature exposure the results are very promising.
Dušan Dolák, , , Dominik Gazdič
Materials Science Forum, Volume 908, pp 56-60;

Thermal treatment of materials involves phase transformations. In the case of conventional laboratory furnace or in an industrial process, the samples are analysed after cooling. In this way, these phases can be monitored. A possible solution is non-ambient XRD analysis. Using HT-XRD analysis, it is possible to monitor the mineralogical composition at different temperatures in real time. The results of measurements on chemically precipitated limestone and limestone from the Cretaceous era show slight differences in temperature of decarbonation, but not clearly demonstrated the presence of unstable phases. This measurement, however, allowed the observation of a change in the size of the crystallites in the change of temperature.
Adam Hubáček, Iveta Hájková
Materials Science Forum, Volume 908, pp 159-163;

Technology of so-called vibro compacted pressed concrete is currently used inter alia for manufacture of concrete products like concrete paving blocks, slabs, curbs or walling elements. Particularly wear layers of products for paving have recently been improved by special methods and technologies. The paper summarizes current knowledge of vibro compacted pressed concrete products with surface finish treated with hardened varnish. Main focus is on description of individual methods of finalizing wear layers of such products.
, , Jurga Šeputytė-Jucikė
Materials Science Forum, Volume 908, pp 134-138;

Currently building sector requires the use of new technologies and innovative materials. Realization of mentioned requirements allow ensuring rate of performed works, reducing labour building constructions costs and improving building performance. In current work, loose fill material from hemp shives and binding material are analysed. The mixture of hemp shives and binder may be used in frame constructions as blown or poured loose fill material for thermal insulation or structural use. Hardened composite is characterized by high strength and excellent thermal conductivity when it is used in building partitions and enclosures. In our work hemp shives are mineralized with different amount of liquid sodium silicate and mixed with cementitious binder. Macro-and microstructures of hardened composite are analysed, influence of amount of mineralizer on the strength and thermal conductivity of composite is evaluated.
Materials Science Forum, Volume 908, pp 88-93;

One of the advantages of concrete over other building materials is its inherent fire-resistive properties. The concrete structural components still must be able to withstand dead and live loads without collapse even though the rise in temperature causes a decrease in the strength and modulus of elasticity for concrete and steel reinforcement. In addition, fully developed fires cause expansion of structural components and the resulting stresses and strains must be resisted. This paper reports the results of measurements by Acoustic Emission method during three-point bending test on concrete specimens. The Acoustic emission method is a non-destructive technique used widely for structural health monitoring purposes of structures. The sensors are mounted by beeswax on the surface of the material or structure to record the motion of the surface under the elastic excitation of the cracking sources. The concrete specimens were heated in a programmable laboratory furnace at a heating rate of 5 °C/min. The specimens were loaded at six temperatures, 200 °C, 400 °C, 600 °C, 800 °C, 1000 °C, and 1200 °C maintained for 60 minutes. The results are obtained in the laboratory.
Adam Hubáček, Iveta Hájková
Materials Science Forum, Volume 908, pp 154-158;

The paper describes problems of water-tight concrete constructions, their design, manufacture and testing of quality in accordance with regulations and directives used in the Czech Republic and abroad. Current knowledge of water-tight constructions and water-tight concrete imply that main focus is on problems of use of water-tight concrete for construction of so-called white bath and preventing crack formation in concrete. Laboratory work is focused mainly on design of concrete based on individual regulations. Subsequently, influence of various types of cement and additions partly replacing cement on properties of water-tight concrete is examined. Research of heat development during hydration at early stages of maturing is and inseparable part of the experimental work, as well as development of compressive strength, water-tightness and frost resistance of concrete
Martin Ťažký, Lenka Bodnárová, Rudolf Hela
Materials Science Forum, Volume 908, pp 106-110;

Increasingly we see today among the conventional high temperature fly ash also with the production of fly ash from fluidized bed combustion. These fluidized bed combustions fly ashes, however, have little used this area, mainly for their chemical composition and morphology. Current efforts are directed towards the development of new technological processes and building materials that would allow the use of this industrial waste and its qualities. One possible way of fluidized bed combustion fly ash’s utilizing in construction industries the production of cold balled lightweight aggregate. Production of this material is economically advantageous and enables processing of large volumes of raw materials. This paper describes possibilities of using this aggregate for production of lightweight construction concrete and consequent testing of durability and resistance to various types of aggressive environment. For these lightweight structural concretes, will be verified in their thermal-technical parameters.
, Jiří Bydžovský, Ámos Dufka, Jindrich Melichar
Materials Science Forum, Volume 908, pp 10-14;

Polymer cement matrix based materials were designed within the frame of the research presented in this paper. Resistance of these materials to combination of several adverse factors was observed. Considerable proportion of input materials used were components from alternative material resources. Primary binder was replaced with fly ash and blast furnace slag. Dominant proportion of filling mass was taken up by agloporite – porous aggregate produced by self-baking from fly ash. The focus of the research was assessment of degradation of materials after long-term exposition (up to 90 days) to increased concentration of sulphate ions and high temperatures. Degree of degradation was evaluated on the basis of physico-mechanical and physico-chemical tests combined with microstructural analyses.
Pavel Reiterman,
Materials Science Forum, Volume 908, pp 40-44;

Application of various pozzolanic materials is the current approach to obtain suitable environmental, economic and durability parameters of composites, in which they are used. Considerable interest is focused on the possibilities of finely ground ceramic powder (CP) exhibiting pozzolanic activity. Present paper is aimed at the experimental study on the monitoring of reaction kinetics in lime-ceramic powder system (1:1). Ceramic powders with controlled grading were used. Reaction capacity was assessed in time by means of thermogravimetry. The dominant effect of the finest fractions (up to 0.030 mm) on the pozzolanic reaction was proved; coarser fractions of used CP exhibited approximately the half reaction efficiency after 28 days of curing.
Karel Kulísek, Dominik Gazdič,
Materials Science Forum, Volume 908, pp 21-25;

Fluidized bed ash, which is the youngest industrial waste can be considered on the basis of research, a high-quality secondary raw material base which can be easily used in the production of Portland cements and, in general, other hydraulic binders. Regarding the direct effect of anhydrite on the course of hydrating mixed cement with the fluidized fly ash and the consequent behaviour of the originated cement stone, its reaction with clinker materials on the mentioned Aft (Al2O3–Fe2O3-–tri) phase is clear. The creation of AFt phases, if they originate additionally, due to their morphology, is accompanied by significant volume changes which may lead to deformation up to the destruction of the cement stone. Some foreign publications show the possibility of the transformation of this thermo-dynamically unstable mineral into the further mineral from the group AFt phase, which is thaumasite, Ca3Si (CO3)(SO4)(OH)6.12H2O.
, Sergii Guzii, Rudolf Hela
Materials Science Forum, Volume 908, pp 63-70;

This paper covers the results of study of the influence of cavitation treatment on nanostructuring of the alkali aluminosilicate binder for intumescent coatings. The results of study suggested to establish optimal parameters of cavitation treatment. At pressure of 20...25 atm, temperature below 30 °С, time of treatment shorter than 10 min rheological properties tend to improve and phase formation processes to accelerate at normal curing temperatures which result in the enhancement of heat engineering and mechanical properties of the intumescent coatings.
, , Antje Täger, Hagen Marks
Solid State Phenomena, Volume 267, pp 114-118;

For electrostatic coating application Sheet Molding Composites (SMC) have to be modified antistatically. By a novel approach several monomeric and polymeric ionic substances were incorporated into the duromeric bulk phase and tested in terms of its antistatic effectiveness. Furthermore the influence of selected additives on the SMC thickening and molding procedure as well as resulting mechanical properties of modified SMC-panels and the powder coating application were studied.
, , Mart Viljus, , Priit Kulu
Solid State Phenomena, Volume 267, pp 195-200;

The present research focuses onto sliding wear of novel plasma transferred arc welded (PTAW) hardfacing with the stainless steel (DIN X3CrNiMo18-13-3) matrix, reinforced with WC/W2C, under the room and elevated temperature. The hardfacing was produced, applying the optimized set of parameters (current – 55 A, reciprocating speed – 1.0 mm/s, oscillation frequency – 0.6 Hz). The average reinforcement content was 29.3 ± 4.0 vol %. The reinforcement consisted of W2C and WC, while M7C3- and M23C6-type (M = Fe, Cr, Mo, W) carbides were the main phases in the matrix. Universal hardness and Young’s modulus were approximately 5.3 and 1.9 times higher, than those of the reference steel (DIN X2CrNiMo18-14-3). The sliding wear of the hardfacing was 4.9 times lower under 20 °C and 3.1 times lower under 300 °C, but 1.8 times higher under 500 °C than the wear of the reference steel. Galling was the wear mechanism of the hardfacing under 20 °C, scoring – under 300 °C and combination of scoring and binder extrusion – under 500 °C
, Armands Buss, , Lasma Malniece
Solid State Phenomena, Volume 267, pp 119-123;

α-Tricalcium phosphate (α-TCP) is an important reactive component in calcium phosphate bone cements which are used for the bone tissue regeneration and augmentation. By thermally treating amorphous calcium phosphate (ACP) at relatively low temperatures (650–900 °C), it is possible to obtain sub-micrometre or nanosized α-TCP particles. In the current research, it is shown that the aqueous synthesis environment where ACP is precipitated has significant influence on the stability of ACP and the α-TCP content in the thermally treated products. During ACP synthesis pH must be kept basic. While it is possible to synthesize ACP if potassium hydroxide or sodium hydroxide is used to raise the pH of synthesis, ammonium ions also must be present in the solution to obtain α-TCP after thermal treatment of ACP. If sodium hydroxide is used, higher α-TCP content is obtained (compare 89 % and 66 %). Increase of Ca/P ratio stabilizes ACP and allows to obtain products with high α-TCP content. Increase of both calcium and phosphate ion concentration in the synthesis destabilizes ACP and reduces the amount of α-TCP in the product (twofold increase reduced α-TCP content from 89% to 2%).
, , Karl Adam, Andreas Kuttner
Solid State Phenomena, Volume 267, pp 234-242;

In heavy industries like mining or steel production vast amounts of loose materials need to be transported, relocated or otherwise processed. During these routines severe stresses are applied on heavy machinery components such as excavator grabs and clamshells, which ultimately lead to excessive wear. The dominant wear mechanisms under such conditions are impact and abrasion. The focus of this paper is to investigate the fracture behaviour of various abrasives as experienced under real application in the steel industry. Breaking events of abrasive particles affect the impact energies on tool equipment. The Cyclic Impact/Abrasion Test rig (CIAT) was applied to investigate the stability and fracture behaviour of the abrasives. Rotating counter bodies made of martensitic quenched and tempered steel were used to generate impact events on loose abrasive particles. After certain time intervals the abrasives were screened and particle size fractions documented. Impact energy is strongly dependent on size and density, as well as fragility and cracking of particles. As fracturing events diminish particle dimensions and shift size distributions to lower size fractions, each abrasive showed a distinctive impact energy distribution over the course of the test duration. Impact energy distributions of abrasives were correlated to wear rates of the steel samples for each abrasive used. The results indicate a distinct behaviour of each abrasive, yielding certain impact energy distributions. Depending on processing specific abrasive goods in actual applications, impact energies and associated wear loss can differ significantly.
Belkacem Bouacherine, Abdelkader Iddou, Hafida Hentit, Jean Claude Jumas, ,
Solid State Phenomena, Volume 267, pp 139-144;

This work is in addition to the various works undertaken by the researchers, using biomass as adsorbent. However, the aim of this study is the recovery of a marine material alga: Ulva lactuca) that we were able to transform into adsorbent with treatment under physical carbonization and chemical activation. The ability of treated and untreated Ulvala ctuca, to remove hexavalent chromium Cr (VI) ions in aqueous solutions was investigated. The influence of pH, sorbent dose, initial concentration, temperature, and contact time has been studied in batch process. The materials are characterized by FTIR and SEM analysis. The highest Cr (VI) removals (100%) were achieved at pH of 3, particle size of less than 250μm, dose of 1 g/L, and equilibrium time of 180 minutes. Thermodynamic results indicated that the Cr (VI) adsorption process was spontaneous and exothermic. The adsorption data fit well with Langmuir isotherm model with a maximum adsorption capacities (qmax) of untreated and treated Ulva lactuca were between 0.6 and 2 mg/g. Higher Cr (VI) removal revealed the practical applicability of Ulva lactuca in water and wastewater treatment systems.
Solid State Phenomena, Volume 267, pp 40-44;

Pneumatic vibroexciters which consist of smart materials’ structural elements and are operating under autovibration regime were designed. The chamber of vibroexciter actuator with changeable capacity for flowing pressured air made of shape memory alloy (SMA) were presented. Mechanical characteristics of such type vibroactuator were estimated: maximum deformation of structural element with SMA, possible force of martensitic transformation. The result of the research allows to design functional adaptive pneumatic vibroexciters with are suitable for the different purposes of technological processes.
Solid State Phenomena, Volume 267, pp 124-131;

Variety of different bone substitutive materials are synthetized to improve bone healing potentials in pathological bone conditions. Physiologically active molecules within biomaterials, can initiate expression level of biomarkers, regulating bone remodeling. Aim of our study was to analyze bone healing process in bone defects followed by implantation with 5% strontium substituted hydroxyapatite (HAP) /tricalcium phosphate (TCP) 70/30 granules (group A) or HAP/TCP biphasic ceramic granules without strontium substitution (group B), or sham surgery affected bone (group C) in osteoporotic rabbits’ femur. Tissue samples from contralateral intact left leg were used for evaluation of systemic effects after surgery. Changes of bone volume were measured and appearance of OPG, NFkB-105, OC, COL-1, BMP-2/4, MMP-2, TIMP-2, IL-1 and IL-10-positive osteocytes in osteoporotic rabbits’ bone defect were evaluated. No statistical difference between groups of trabecular bone volume was detected. All analyzed markers showed higher appearance of positive osteocytes in groups A and B with comparison to control left leg (p<0.05). Only NFkB105-positive cells showed important difference between sham surgery affected leg and control one (p=0.034). Numerous OPG-positive cells appeared in group A, while moderate number of them was found in groups B and C (p=0.025; p=0.027). Numerous to abundant OC-positive osteocytes were detected in group A, while moderate in group C (p=0.034). Statistical difference of rest biomarkers between groups was not detected. We concluded that implantation of biomaterials in osteoporotic bone improves local bone regenerative properties. However, the notable increase of OPG-containing cells proves the increase of osteoclastogenesis suppression and gives the evidence for renew of bone functionality.
Marek Góral, Tadeusz Kubaszek
Solid State Phenomena, Volume 267, pp 243-247;

Thermal Barrier Coatings (TBC) is the most advanced system for protection of turbine blades and vanes against high temperature, and oxidation. They are used in most advanced jet engines. In present article the new Plasma Spray Physical Vapour Deposition Technology was used to obtain yttria stabilized zirconia oxide coating with columnar structure. In research the different process parameters were changed. It was observed that powder feed rate had big influence on coating thickness. The large amount of Ar in plasma gasses combined with high powder feed rate resulted in partial evaporation of ceramic powder and splat-type structure. The same effect was observed when the power current was decreased form 2400 to 1600 A as well as pressure was increased to 200 Pa when the powder feed rate was 30 g/min. The obtained results showed that full evaporation of ceramic powder requires very low feed rate of ceramic material (2 g/min), high power current and high He content into plasma.
Ali Ozturk
Solid State Phenomena, Volume 267, pp 177-181;

This paper presents how to calculate the overall heat transfer coefficient of a very long functionally graded hollow circular cylinder subjected to steady state heat transfer. Thermal conductivity coefficient of the functionally graded cylinder (FGC) vary radially and continuously according to an exponential form, which is supposed to be independent of the temperature. Overall heat transfer coefficient is found analytically in terms of the radial coordinate, thermal conductivity, material parameter, inner surface and outer surface temperatures of the cylinder. Once the overall heat transfer coefficient is found, calculation of the heat transfer rate across the cylinder wall is quite straightforward. The equation derived for the overall heat transfer coefficient can be applied to any type of functionally graded hollow circular cylinder playing with the material parameter term.
Jevgenijs Jaunslavietis, , Jurijs Ozolins, Brigita Neiberte, Anrijs Verovkins, , Vadims Shakels
Solid State Phenomena, Volume 267, pp 68-75;

The aim of the study was to evaluate the surface energetic characteristics of wood-polymer composites (WPCs) based on recycled polypropylene (rPP) filled with ammoxidised lignocellulosic microparticles, obtained from aspen sawdust, a by-product of a Latvian company. The aspen sawdust, pre-hydrolysed in acidic medium, was treated with a reaction mixture of ammonium persulphate and NH4OH solution at their defined mass ratio during 120 h. The content of the introduced nitrogen was varied from 1,05 to 2,10%. It was found that the ammoxidation that was accompanied with the formation of amide linkages and the decrease of the hemicelluloses content enhanced the contact angles, decreased the work of adhesion and reduced the surface free energy of the WPC samples in comparison with the case of the composite filled with the initial sawdust. The valorisation of the wood particles increased their wettability towards the recycled polypropylene that had a positive effect on the WPC samples’ mechanical properties.
Solid State Phenomena, Volume 267, pp 82-86;

Cr3C2-Ni cermets exhibit high hardness and excellent corrosion, oxidation, abrasive and erosion resistance. However, nickel is toxic and carcinogen and because of that great efforts were made to displace or replace nickel in the composition of cermets. Therefore, in the present research chromium carbide-based cermets with FeCr-type ferritic binder was fabricated and investigated. Composites were sintered at different conditions: vacuum and spark plasma sintering. Spark plasma sintered cermets demonstrated acceptable structure and mechanical characteristics. Chemical composition of chromium carbide-based iron alloy bonded cermets was analyzed by energy-dispersive X-ray spectroscopy and structural analysis was carried out using X-ray diffraction. Sintered cermet consists of two main phases: α-Fe and (Cr,Fe)7C3 complex dicarbide. Mechanical characterizations – hardness and fracture toughness – was performed. Also oxidation rates were determined.
, , Mārtiņš Kalniņš
Solid State Phenomena, Volume 267, pp 7-11;

This report explores two key manufacturing processes, and assesses multiple parameters for optimization of these processes. High shear dispersion using a rotor-stator style homogenizer and high-energy grinding using a basket type mill with zirconium balls as the grinding media were studied. The variation between grinding organic and inorganic pigments was assessed as they give different challenges and require different operations to produce successful results. Obtaining the correct particle size distribution of pigments for decorative coatings is of paramount importance for achieving a high quality, functioning, aesthetically pleasing finished product. This analysis will explore the de-agglomeration and dispersion of inorganic TiO2 and organic Red 6 pigments using basket milling technology. High energy basket mill grinding produced the smallest particle size and smallest particle size distribution comparing with high shear dispersion. Used technology allowed to achieve inorganic pigment TiO2 particle size and particle size distribution suitable for use in coatings on natural nails. For organic pigment Red 6 used technology should be customized.
Alexey Tatarinov, Viktor Mironov, Dmitry Rybak, Pavels Stankevich
Solid State Phenomena, Volume 267, pp 248-252;

Possibilities of non-destructive testing (NDT) methods to assess the quality of permanent joints of powder metal parts were evaluated. Antifriction bushing-bushing couples used in transport braking systems were investigated. The parts made of bronze graphite were crimped by pulsed magnetic deformation by means of electromagnetic equipment with a maximum discharge energy of 30 kJ. The gap between joint parts in the couples was assessed by ultrasonic and radiographic methods. A standard ultrasonic flaw detector Krautkramer USM-25 with an Olympus 4MHz dual-element echo transducer and an industrial x-ray apparatus YXLON EVO 200D were used, correspondingly. In first trial, both methods were equally sensitive to tight and weak connection of joints.
Maxim Yashin, , Pradeep L. Menezes, Mart Viljus, Taavi Raadik, Andrei Bogatov, ,
Solid State Phenomena, Volume 267, pp 219-223;

The present study deals with the tribological behavior of nanocrystalline diamond (NCD) coatings at high temperature sliding conditions. The NCD coatings were grown by plasma enhanced chemical vapor deposition (PECVD) method on the hard metal (WC-Co) substrates. The friction and wear tests were performed on ball-on-disc tribometer using a high-temperature chamber with rotary drive. The tests were carried out at room temperature, 300, 450 and 600 °C. The scanning electron microscopy (SEM), optical microscopy, mechanical profilometry and Raman spectrometry were used for investigation of the morphology and chemical composition of the wear scars and pristine surface. The depth and width of the wear scars measured after the high temperature sliding tests are larger in comparison with room temperature tests. It was observed that the coefficient of friction (COF) increased with increasing temperature. The wear rate of NCD coatings tested at 300-450° C was about 10 times higher than that at room temperature. The mechanisms involved for these variations are discussed.
Radomila Konečná, , Pavel Pokorný,
Solid State Phenomena, Volume 267, pp 157-161;

Growth of long fatigue cracks in Ti6Al4V alloy manufactured by direct metal laser sintering (DMLS) was investigated. Two DMLS systems, EOSINT M270 and EOSINT M290, with different process parameters were used for production of CT specimens having three different orientations of crack propagation with respect to the DMLS build direction. The as-built specimens were stress relieved at 740 °C. The fatigue crack growth curve and the threshold values of the stress intensity factor for crack propagation were experimentally determined. It has been found that the chosen DMLS processing parameters and the used stress relieving procedure results in material exhibiting isotropic crack growth behavior, i.e. the crack growth was found to be independent of the DMLS build direction. The fatigue crack growth rates and the threshold values for the crack growth were compared with published results characterizing the as-built material and material after different post processing heat treatments.
Solid State Phenomena, Volume 267, pp 151-156;

In the present study, buckling of eccentrically loaded nanobeams in which the load is not applied at the centroid of cross section, has been studied. Eringen’s Nonlocal Elasticity Theory has been used in the formulation of governing equation of motion of the nanobeam. Simply supported and free boundary conditions for nanobeam have been taken consideration. The effect of nonlocal parameter, eccentricity of the load, nanobeam length on the buckling deflection and critical buckling load on nanobeam have been investigated. Present results can be useful in the design of nano-structures.
, Andrejs Skagers
Solid State Phenomena, Volume 267, pp 145-148;

Sinus floor augmentation operations with calcium phosphate materials are performed when natural maxillary bone quality and quantity fail to be able to support titanium dental implants. Sinus floor augmentation can be done in one step operation when titanium implant is inserted at the same time when calcium phosphate materials. This type surgery can be done if there is enough maxillary alveolar bone height to stabilize the implant. If there is not enough bone then two step maxillary floor augmentation is performed when dental implant is placed after few months. Calcium phosphate materials are often used for maxillary sinus augmentation. These materials cause remineralization of residual maxillary alveolar bone [1]. That can be observed histologically [2,3]. However histological evaluation often means interference. Radiological investigation can be used to examine postoperatively augmented area. Nowadays cone beam computed tomography (CBCT) is the radiological method of choice for maxillofacial region due to low radiation and high quality images. There was no date found in literature on maxillary bone remineralization measured in voxel grey value density (VV) on CBCT. Rotation movement of CBCT cause beam hardening artifacts [4,5] that can alter correct measurements of bone and augmentation zone radiodensity. The aim of this study was to calculate remineralization of maxillary alveolar bone after augmentation with calcium phosphate materials radiologically and degree of artifacts created by titanium dental implant in CBCT images.
Ritvars Berzins, ,
Solid State Phenomena, Volume 267, pp 28-34;

Two component model systems from Silyl-terminated polyether (SAX 520) and epoxy resin (D.E.R. 331) can produce higher mechanical properties than each system individually. This work is dedicated to explore two components (SAX 520/D.E.R. 331) systems and represent their benefits comparing to neat SAX 520 based system. Work shows that compositions with epoxy resin not only improves material mechanical properties, but also its stability after aging, workability time and adhesion on various substrates.
Sinan Sezek,
Solid State Phenomena, Volume 267, pp 45-51;

In this study, temperature distribution that occurred during cold and hot rolling of AA5454-O alloy has been investigated. Temperature variation taking place in the aluminium alloy that has undergone plastic deformation between the rollers during hot and cold rolling process is of major importance in terms of determining the positive and negative characteristics or features which such temperature variation adds to the formation of the internal structure of the material concerned. Temperature distribution has been measured by use of the installed laboratory equipment and respective data recorded has been presented in the form of graphic charts. Temperature distribution has varied depending on the application of hot or cold rolling process and it has been noted that variations in terms of temperature reduction took place depending on the number of roll passes. While average temperature variation has occurred as a 16°C increase in the case of cold rolling, it has been observed that such variation appeared as a 100°C decrease on the average in the case of hot rolling.
Tadeusz Kubaszek, Marek Góral
Solid State Phenomena, Volume 267, pp 207-211;

The aim of this study was to examine the possibility of application in APS process Yttria Stabilized Zirconia (YSZ) – Metco 6700 ceramic powder normally used in Low Pressure Plasma Spraying (LPPS) method. Powder grain size is around 10 µm. Parameters such as chemical composition of plasma gases and current were changed to obtain the best result. The experiment was divided into two stages. Firstly, temperature, velocity and size of a molten particle of ceramic powder inside plasma plume were measured via DPV eVolution equipment (TECNAR company) during a different set of process parameters. Plasma plume was also scanned to obtain cross-section contour plots of mentioned properties of the molten particle. Secondly, the same processes were repeated to deposit TBC coatings onto sheet metal to examine the structure.The obtained results showed that it is possible to use fine-grain YSZ powder Metco 6700 for APS process. Obtained ceramic coatings had a thickness from 100 to 240 µm. The plasma sprayed coating was characterised by a smooth surface. The measurement of spraying parameters showed the uniform temperature, velocity and particle size of the powder inside plasma plume.
Marianna Laka, Marite Skute, Sarmite Janceva, Velta Fridrihsone, , Linda Vecbiskena, Uldis Grinfelds, Laura Andze, Juris Zoldners
Solid State Phenomena, Volume 267, pp 12-16;

For reinforcing of paper, nanoparticle gels from black alder, birch and pine bark were obtained. Non-extracted bark and that extracted in biorefinery were used. For producing nanoparticles, the materials were destructed using the thermocatalytic destruction method and then dispersed in water medium in a ball mill. At a sufficient concentration, gel-like dispersions were obtained, which contained nanoparticles with the size ~300 nm. The effect of nanoparticle gels on the properties of paper sheets was investigated by introducing the dissolved gels in paper furnish and by covering both sides of paper sheets with nanoparticle gel coatings. It has been established that the nanoparticle fillers increase the tensile and burst strength. The nanoparticle fillers from extracted bark increase the mechanical indices to a higher extent. The coatings from nanoparticle gels considerably improve the Gurley air resistance of paper and increase the mechanical indices of paper sheets, especially burst strength. The effect of nanoparticle gel coatings is dependent on the coating thickness and gel concentration. The coatings decrease the tensile strength in a wet state.
Jing Fu Song, , Qing Jun Ding, Jin Hao Qiu
Solid State Phenomena, Volume 267, pp 253-257;

Space exploitation and development need high-performance polymer based tribo-materials in order to reduce the weight and improve the reliability of mechanical moving components. However, the wear resistance of polymer composites will decrease after space irradiation. In order to improve the anti-irradiation and wear resistance, the high performance polyimide (PI) composites reinforced with aramid fibers (AF), filled with polytetrafluoroethylene (PTFE) and Al2O3were designed and prepared using hot press sintering. The effect of the individual atomic oxygen or proton irradiation as well as both on the tribological properties of the PI composites were systematically investigated against Si3N4 ball on a ball-on-disk test rig under simulating space environment system, and coefficient of friction and wear rate were considered as responses. The worn surfaces of the composites were observed by scanning electrical microscopy to reveal wear mechanisms of the materials’ damage. Experimental results indicated that the wear rate of the PTFE/AF/PI greatly increased after atomic oxygen and proton irradiation due to oxidation degradation effect on the polymer matrix. However, filling Al2O3 nano-particles into polyimide matrix can improve the wear resistance because of oxidation layer, gradually formulated during the process of atomic oxygen irradiation, which can protect the polymer composites and avoid further oxidation. This study will expect to provide the helpful guidance for designing high performance polymer based frictional materials in the application of space science.
, , Algirdas Sužiedėlis, Aldis Šilėnas, Edmundas Širmulis, Vitas Švedas, Viktoras Vaičikauskas, Vytautas Vaičiūnas, Darius Valiulis, Ovidijus Žalys, et al.
Solid State Phenomena, Volume 267, pp 167-171;

Photovoltage formation across Si and GaAs p-n junctions exposed to laser radiation is experimentally investigated. When the photon energy is lower than semiconductor forbidden energy gap, the photovoltage is found to consist of two components, U=Uf+ Uph. The first one Uf is fast having polarity of thermoelectromotive force of hot carriers. The second one Uphis slow component of opposite polarity, and it is caused by electron-hole pair generation due to two-photon absorption. Uph was shown to decrease with the rise of radiation wavelength due to diminution of two-photon absorption coefficient with wavelength. Predominance of each separate component in the formation of the net photovoltage depends on both laser wavelength and intensity.
Laura Rozenberga-Voska, Jānis Grabis
Solid State Phenomena, Volume 267, pp 3-6;

TiO2 and silver doped TiO2 thin films were prepared by spray pyrolysis technique and their photocatalytic activity were determined. Titanium(IV) isopropoxide solution or its mixture with silver nitrate were used as precursors. As-prepared at 300 °C films were X-ray amorphous. Calcination of the films at 500 °C for 5 – 6 hours allowed to obtain partially crystalline anatase films with uniform grain size in the range of 80 – 150 nm. Degradation degree of MB water solution by using TiO2 and TiO2/Ag photocatalysts under UV irradiation reached 60 and 70 % respectively.
Kakur Naresh, Shankar Krishnapillai, Ramachandran Velmurugan
Solid State Phenomena, Volume 267, pp 103-108;

In this study, the Interlaminar shear strength (ILSS) and flexural properties for five different laminate orientations [0°, 45°, [45°/-45°/45°]s, [±45°/0°/90°]s and 90°] of unidirectional carbon fiber reinforced plastic (CRP) and glass fiber reinforced plastic (GRP) composites are investigated. The different approach is used by applying the tensile load on notched specimens for measuring the inter-laminar shear strength. The theoretical flexural properties are obtained using the classical laminate theory [CLT]. The good agreement is obtained between the theoretical model and experimental results. The results indicate that the flexural strength and stiffness are higher for 0° laminate whereas flexural strain is higher for [45°/-45°/45°]s laminates as compared to other laminates. The scanning electron microscopy is used to observe the fracture surface of all laminate orientations of CRP and GRP composites.
Emrah Madenci,
Solid State Phenomena, Volume 267, pp 35-39;

The main objective of the present study is to give a systematic way for the derivation of laminated composite plates by using the mixed type finite element formulation with a functional. The first order shear deformation plate theory is used. Differential field equations of composite plates are derived from virtual displacement principle. These equations were written in operator form then by using the Gâteaux differential method, a new functional which including the dynamic and geometric boundary conditions is obtained after provide potential conditions. Applying mixed-type finite element based on this new functional, a plate element namely FOPLT32 is derived which have 8 degrees of freedoms on per node, total 32 freedoms. The reliability of the derived FOPLT32 plate elements for static analysis is verified, since the results obtained have been shown to agree well with the existing ones.
, Mürsel Ekrem
Solid State Phenomena, Volume 267, pp 23-27;

In this study, the production of weight ratios of 1, 3 and 5 % multi-walled carbon nanotubes (MWCNT) reinforced / unreinforced Nylon 6,6 (N-6,6) nanofiber mats was carried out by electro spun method. Tensile strength (sT), modulus of elasticity (E), toughness and elongation amounts were investigated by tensile tests under static loading with / without reinforced nanofiber mats. % 3 MWCNT reinforced N-6,6 nanofiber mats, tensile strength, E and toughness increased by 84.4, 235 and 112 %, respectively, when compared with N-6,6 nanofiber mats. In addition, scanning electron microscope (SEM) images were also investigated to determine the physical properties at the specification of reinforced /unreinforced N-6,6 nanofiber mats.
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