bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Investigation of Non-Linear Insulator against Surface Tracking on Wind Turbine Blade Surface
Authors: Sasimma Watthanapong , Suksri Amnart
Published: March 2014

This research work investigates the surface degradation of wind turbine blade surface insulator which is made from modified epoxy resin mixed with Zinc oxide (ZnO) and Aluminium oxide (Al2O3) in different percentage as a filler elements. Accelerated test with AC voltage of 4.5 kV 50 Hz with NH4Cl saline solution using flow rate of contaminant equals to 0.6 ml/min according to IEC 60587 standard. It was found that, the solid insulators which has 30 % of Zinc oxide (ZnO) and 20% of Aluminium oxide (Al2O3) fillers prolong the process of surface tracking to the order of 5.41 for Zinc oxide (ZnO) filler and also to the order of 30.68 for Aluminium oxide (Al2O3) filler. On the other hand, if the amount of Aluminium oxide (Al2O3) filler is more than 20% by weight, it will lead to a rapid tracking phenomena.
Deposition of BaZr0.10Ti0.90O3 Thin Films Doped Strontium by Sol Gel Method
Authors: Iriani Y , Saputri D.F. , Hadiati S. , Ramelan A.H. , Variani V. I
Published: March 2014

Depositions of BaZr0.10Ti0.90O3 and BaZr0.10Ti0.90O3 thin films doped with strontium (Sr) have been growth on Pt/Si substrate using the sol gel method prepared with spin coater. Mole percent of Sr is varied to 1%, 3% and 5%, repectively. The characterization of its micro structure showed that the diffraction angle is shifted to the right if the mole percent of the Sr doped is increased. We found that the particle size of BZT with Sr dopant is bigger than BZT without dopant Sr as shown in the morphological characterization result. The thickness of BaZr0.10Ti0.90O3 and BaZr0.10Ti0.90O3 thin films doped with Sr are about 400 nm. The obtained hysteresis curves of BaZr0.10Ti0.90O3 and BaZr0.10Ti0.90O3 thin films shown that the saturation values are similar to each other, however the remnant polarization and coercive field geting smaller along with the increasing of mole percent of Sr dopant.
Induction Hardening of Carbon Steel Material: The Effect of Specimen Diameter
Authors: Ismail Rifky , Prasetyo Dian Indra , Tauviqirrahman Mohammad , Yohana Eflita , Bayuseno A.P.
Published: March 2014

Induction hardening is well developed technology in many industrial applications, e.g. automotive, tool manufacturing, casting technology, sheet metal forming etc. The surface hardened medium carbon steels are widely used for critical automotive and machine components such as propulsion shafts, crankshafts and steering knuckles which require high fatigue resistance. However, some of small and medium sized enterprises, focused in metal manufacturing in Indonesia have not complete practical knowledge in employing induction hardening to harden the mechanical components. This paper present a technical report of induction hardening process for medium carbon steel material with considering the effect of specimen diameter. The results show that the increase of the specimen diameter increases the current input requirement which also increase the power requirement as a consequence. The induction frequency is automatically decrease when the specimen diameter is increase and resulted in the deeper hardening layer on the surface. The hardness layer of specimen A ranges from outer surface to 6 mm from the surface whereas specimen B ranges from outer surface to 10 mm from the surface from. The micro structure evolution from the surface to the center of the specimen for the both specimen is almost similar. It is mostly affected by the heating temperature and heat distribution from the surface to the center of specimen.
Diamond Microelectrodes for Amperometric Oxygen Sensor
Authors: Cheirsirikul Somsak , Mongkolkiartichai Tosnus
Published: March 2014

This report Studied and development of diamond microelectrodes for Amperometric oxygen sensor. Boron-doped diamond film was Synthesized on a Si substrate by Hot-Filament CVD with the optimization Condition for film thickness 5 μm. This diamond film has the active area of electrode Control dimensions by technique uses SiO2 be a mask Protecting diamond film formation. Four-point probe in additional and Hall Effect technique were used to measure the resistivity, and to measure carriers concentrations of the respectively. Study electrochemistry characteristics of diamond electrodes using Cyclic Voltammetry method. These B/C 10,000 PPM Boron doped diamond electrodes are used as working electrodes of Amperometric oxygen sensor for various of this gas levels detection. These electrodes are packaged with 0.1M KCl solution. The experiment show that current density of the diamond microelectrodes with 100 μm spacing was greater than the current density of the diamond microelectrodes with 40 μm spacing and the planar diamond electrode.
Materials and Processes in Heat Assisted Magnetic Recording
Authors: Gavrilă Horia Catalin , Gavrilă Doina Elena
Published: March 2014

The conventional magnetic recording has approached its physical limits. Further growth of the areal density is limited by the superparamagnetic effect and by the limited possibilities to further improve write heads design and pole materials in order to enhance the writing field. A new technology proposed to surpass these limits is the heat assisted magnetic recording (HAMR). The principle of HAMR and the structure of a HAMR system are discussed, as well as the processes characterizing the writing process and the requirements for the materials needed for this type of recording. Some important challenges of the HAMR technology are summarized.
Thermal Insulating Materials for Energy Storage Application
Authors: Petranek Vít , Nevřivová Lenka , Zezulova Dana , Guziy Sergey
Published: March 2014

In this paper various thermal energy storage mechanisms are overviewed. Furthermore, the effectiveness of three insulating materials based on alkali activated and prepared with different expanded perlite filler contents was investigated. The results showed that the developed materials could be used to insulate a thermal energy storage facility, operating in the temperature range of 650-800 °C.
Biogrowth of Escherichia coli in Bio-Ionic Media
Authors: Sihab Aimi Liyana , Ramli Maisarah , Azizan Amizon
Published: March 2014

The impact of development of ionic liquids (ILs) in biochemical appliances has attracted attention from many researchers to further investigate on the potential of ILs. Use of ILs has provided an effective alternative in the conversion of source of carbohydrate in woody plant into fermentable sugar for ethanol production. To investigate how the presence of ILs affects the fermentation process, fermentation by using E. coli were conducted in different fermentation conditions with the presence of ILs. The purpose of this research is to investigate microbial growth under the presence of ILs with various parameters. Ability of E. coli to grow in facultative condition has made these bacteria suitable for this research. In this research, the growths of E. coli in the presence of ILs were observed by shaken culture method for 24 hours. The E. coli was tested to grow in 5 % v/v [0.005, 20 % v/v [0.02, and 50 % v/v [0.05 of IL concentration ratios. The three types of ILs used for this research were 1-Ethyl-3-methylimidazolium Acetate [EMIM][A, 1-Butyl-3-methylimidazolium Chloride [BMIM][Cl] and 1-Allyl-3-methylimidazolium Chloride [AMIM][Cl]. The growth patterns of E. coli were also observed during the fermentation with shaking frequency of 250 rpm, 300 rpm and 350 rpm.
Adsorption of Methyl Violet Dye from Aqueous Solutions by Activated Carbon Produced from Tamarind Seeds
Authors: Phatai Piaw , Klinkaewnarong Jutharatana , Yaiyen Surachai
Published: March 2014

The present work proposes the adsorption of methyl violet (MV) from two solution systems including single MV and binary MV-Cu2+ systems by activated carbon (AC) prepared from tamarind seeds in a batch system. Parameters including contact time, solution pH, adsorbent dose, and initial dye concentration were studied. The morphology of the AC was determined by scanning electron microscopy (SEM). The results showed the maximum adsorption of MV dye onto the AC at a contact time of 60 min, solution pH of 9.0 and adsorbent dose of 0.2 and 0.5 g for the single and binary solution systems, respectively. The presence of copper ions in binary solution system decreased the adsorption efficiency of MV dye onto the AC. The equilibrium adsorption data were analyzed using Langmuir, Freundlich and Temkin isotherms.
Modulation of Fibrin Gel Extracellular Matrix Properties by Fibrinogen and Thrombin Concentrations for Angiogenesis Assay
Authors: Ishak Siti Amirah , Sukmana Irza
Published: March 2014

Angiogenesis is the formation of new microvascular network from the pre-existing blood vessel. In tissue engineering approaches, angiogenesis is essential for the promotion of micro-vascular network inside an engineered scaffold construct, mimicking a functional blood vessel in vivo. In the in vivo system, the formation of new blood vessels depends on the properties fibrin gel extracellular matrix. In this study, we have investigated the effect of different fibrinogen and thrombin composition on the biophysical properties of fibrin gel. Higher concentration of thrombin (4.0 Units/milliliter) yields a shorter clotting time of the fibrin gel and result in better water uptake property while at lower concentration of thrombin (0.5 Units/milliliter), the clotting time takes much longer. Also, at lowest concentration ratio of fibrinogen to thrombin (0.5 milligram/milliliter to 4.0 Units/milliliter), the turbidity study shows the lowest absorbance compared to other samples. Different concentration of fibrinogen and thrombin also affect the microstructure of the fibrin gel. The variation of these properties will be then manipulated to be used for in vitro angiogenesis. This study opens broader application of fibrin extracellular matrix in regenerative medicine and tissue engineering researches.
The Effect of Backbone Disorder on Electrical Conductivity of Poly(dG)-Poly(dC) DNA Molecule at Room Temperature
Authors: Yudiarsah Efta , Suhendro Daniel K. , Saleh Rosari
Published: March 2014

Tight binding Hamiltonian model has been used in studying the influence of the surrounding medium on electrical conductivity of a Poly (dG)-Poly (dC) DNA molecule. This effect is studied in room temperature by taking into account twisting motion with two different low frequencies separately. Transfer matrix technique and scattering matrix method have been employed simultaneously. The current voltage characteristics and the differential conductance show that as the backbone disorder increases, the current decreases and the threshold voltage rises. However as the backbone disorder continues to increase, the reverse of the above phenomenon is observed.
A Study on the Hard Wearing UV Treated Photopolymer Printing Plate for Articular Replacement/Arthroplasty (Biomedical)
Authors: Rejab Noor Azlina , Yusof Mohd Sallehuddin , Maksud M.I. , Nodin M.N.
Published: March 2014

Nowadays the usage of polymer on articular replacement (arthropasty) is common because of their known usage in orthopedic surgery and biocompatibility. The polymeric material such as polyethylene and polyacetal are common materials used in surgical repair of joint due to the arthritic or dysfunctional joint surface. The surgical repair is done by replacing the damage part with something better or remodeling or realigning the joint by osteotomy procedures. In this case, for both hip and knee replacement, chrome-cobalt and polymer are commonly used. According to Jennifer Brown, the cost for knee replacement is approximate to USD$15,000 per procedure with the estimation of total knee replacement is 600,000 annually in United States. Currently, the aggregate of annual cost for total knee replacement is about USD$9 billion. The usage of chrome-cobalt and polymer is very common and save but the cost is very expensive. The other disadvantage is it usually last only for 10 years for hip and knee replacement.
Discharge Assessment by Using Integrated Hydrologic Model for Environmental Technology Development
Authors: Ali Mohd Fozi , Rahman Nor Faiza A. , Khalid Khairi
Published: March 2014

River water quality degradation is one of the most significant environmental challenges. Over the years, many models have been used to investigate the current state of Malaysian rivers and its effects to the environment. River discharge is an important factor in water quality investigation. An integrative computational model, GIS coupled with SWAT model was being used to predict river discharge of this research. The simulation results in the period 1999 to 2010 represented fluctuation of discharge relatively well with both R2 and NSI values were above 0.6. The results proved that the development of integrative GIS technology coupled with SWAT model is a good tool for environmental technology development in terms of investigating the current state of Langat river water quality as well as the capability of simulating the river discharge in the river basin. This shows that GIS-SWAT interface can be a reliable tool for water quality modeling in Malaysia in the future and further development on the software technology is a benefit for the water resources and environmental studies.
The Study of Soil Physical and Chemical Properties in Plant Genetic Protection Area of RSPG, Nampung Dam EGAT, Thailand
Authors: Charoonphong Wanichaya , Suwanwaree Pongthep
Published: March 2014

This work aims to study soil physical and chemical properties in two forest types including dry dipterocarp forest (DDF) and mixed deciduous forest (MDF) located in Plant Genetic Protection Area under the Royal Initiative of Her Royal Highness Princess Maha Chakri Sirindhorn, Nampung dam EGAT, Sakon Nakhon province, Thailand. The samples were collected 3 times in December 2011, February and May 2012. The results showed that the average values of soil properties in MDF including, soil moisture, electical conductivity, organic matter, total nitrogen, avialable phosphorus and exchangeable potassium were higher than those in DDF. Only soil pH in MDF was less than that in DDF. It can be concluded that MDF have more fertility status of soil than DDF.
Physical Contaminants Removal from Continuous Process of Water Filtration by a New Low-Cost Palm Shell Charcoal
Authors: Budari Noraini Mat , Ali Mohd Fozi , Kassim Jalina
Published: March 2014

Drinking water contamination is one of the most major environmental concerns that requires worldwide attention. It is now universally agreed that by supplying the community with safe water, the plague of waterborne diseases can be prevented. The increasing global concern about the environment is the utilization of agricultural waste transformation into wealth material for value-added products which should be given priority. Therefore, this study is using granular bed filtration as a vigorous, simple and economical method to prevent the physical contamination, by discovering an alternative filter media from local sources; namely the palm shell charcoal (PSC). Dual-media filtration PSC/sand ES 1.0/0.5 mm is operates at an optimum condition of removing 80.77% of turbidity, 76.23% of suspended solid and 59.45% of colour in 5 m/h flow rate.There was a statistically significant difference between types of media filter to the removal of physical variable at 0.05 levels as determined by one-way anova for the percentage removal of turbidity (p < 0.001), suspended solid (p < 0.001) and colour (p < 0.001).The PSC was identified as a potential filter media that will help in reducing the cost of water and wastewater treatment and enhancing environmental sustainability. The results from this study suggests that the PSC should be significantly used as a new biodegradable medium filter and for the removal of physical contaminants such turbidity, suspended solid and colour.
Development of Ca(OH)2 Nanosorbent for Intermediate-High Temperature CO2 Capture via Wet Chemical Route in N,N-Dimethylformamide Solvent
Authors: Mohd Daud Farah Diana , Sreekantan Srimala , Mohamed Abdul Rahman
Published: March 2014

CO2 is the major anthropogenic greenhouse gas which contributes to the increasing atmospheric CO2 concentration, leading to serious global warming and climate change. Thus, the present paper investigates the CO2-capture performance of synthesized calcium hydroxides, Ca (OH)2nanosorbent at intermediate-high temperatures which are 350, 450, 550 and 650oC. CO2 adsorption performance was analysed by thermo-gravimetricanalyser (TGA).The CO2 adsorption temperature strongly influenced the capture performance of the sorbent.Facile wet chemical technique was utilized to synthesize Ca (OH)2 nanorod sorbent structures using calcium nitrate tetrahydrate, Ca (NO3)2.4H2O as the calcium precursor, and precipitated with sodium hydroxides (NaOH) in N,N-Dimethylformamide (DMF) mixed deionized (DI) water media at 55 oC. X-ray diffraction (XRD) result exhibitedCa (OH)2hexagonal crystal structures. The Ca (OH)2 particle size and morphological properties before and after CO2 adsorption are studied by Field Emission Scanning Electron Microscopy (FESEM). The FESEM image indeed showed the rod like shape of Ca (OH)2nanosorbent with rod length approximately700 nm while the diameter 140nm. When CO2 molecules were adsorbed by Ca (OH)2nanosorbent, the nanorodstructures are changed to rigid interconnected each other like a lump shaped. Ca (OH)2nanosorbentseems to be a potentially good absorbent for capturing CO2when increased temperatures. However, at intermediate temperature 350 and 450oC, the synthesized Ca (OH)2nanosorbent demonstrated higher CO2 adsorption (141 to 220 mg/g CO2) than others intermediate temperature CO2 sorbent such as layer double hydroxides (LDH), lithium zirconates (LiZrO3) and hydrotalcite.
Novel Aragonite CaCO3 Adsorbents: Synthesis, Characterization and CO2 Adsorption
Authors: Hlaing Nwe Ni , Sreekantan Srimala , Othman Radzali , Hinode Hirofumi , Kurniawan Winarto , Thant Aye Aye , Mohamed Abdul Rahman , Salime Chris
Published: March 2014

In this paper, one dimensional nanorod CaCO3 adsorbents were synthesized via hydrothermal method by varying the amount of polyacrylamide (PAM). The XRD results indicated that all of the characteristic peaks of synthesized adsorbents were matched well with the aragonite CaCO3 phase. FE-SEM analysis showed one dimensional nanorod structures with diameter of 40 - 70 nm and lengths up to micrometer. TG results exhibited CaCO3 adsorbents synthesized with 0.4 and 0.6 g of polyacrylamide possessed high CO2 adsorption capacities for first carbonation/calcination cycle (0.86 and 0.79 g-CO2/g-sorbent) which were higher than the theoretical CO2 adsorption capacity (0.78 g-CO2/g-sorbent) of calcium oxide based adsorbents.
Porous Concrete Pavement Containing Nano-Silica: Pre-Review
Authors: Ramadhansyah P.J. , Mohd Ibrahim Mohd Yusak , Hainin Mohd Rosli , Warid Muhammad Naqiuddin Mohd , Wan Ibrahim Mohd Haziman
Published: March 2014

Porous concrete pavement is being used as one of the solution to decrease the storm water runoff by capturing and allowing rain water to drain into the land surface. The main problem of porous concrete pavement is the strength itself. The objective of this paper is to review the use and performance of nanosilica in porous concrete pavement. From the literature review of the previous research, it was found that the conventional porous concrete pavement doesn't has good strength for pavement purpose. An addition of nanomaterial will improve the physical and chemical properties of the porous concrete pavement.
Fatigue Life Prediction of Austenitic Type 316L Stainless Steel Using ABAQUS
Authors: Mohammad Khairul Azhar , Salit Mohd Sapuan , Zainudin Edi Syams , Zahari Nur Ismarubie , Aidy Ali
Published: March 2014

This work has carried out on Type 316L stainless steel of hollow bar specimen. The aim of this work is to determine the fatigue life prediction using Finite Element Analysis (FEA). The simulation performed by applied the different stress level to predict the stress of operation to measured life at the measured of operation stress. The simulation emphasis is focused upon the importance of characterize the fatigue limit with compared to data experimental. Comparison of fatigue limit between both simulation and experiment is 150 MPa and 161 MPa, respectively which will provide good agreement in terms of accuracy prediction even various aspects should be taken into account in simulation.
Study of Pore Closure Mechanism of Aluminium Composite Processed through Powder Metallurgy Route
Authors: Rajeshkannan Ananthanarayanan , Sharma Bibhya
Published: March 2014

Hot swaging experiments were carried out on as-sintered Al composite preforms in order to evaluate its pore closure characteristics. The effect of tungsten carbide and iron carbide in plain aluminium has been investigated under triaxial stress state condition. Cylindrical preforms with 0.5 aspect ratio and 88% fractional theoretical density have been produced for pure Al, Al-2WC and Al-2WC-4Fe3C through classical powder metallurgy route. Then, the as-sintered preforms are hot swaged to various height strains to further enclose the residual porosities; thereby to enhance density and mechanical properties. It is observed that induced strain substantially helped to close the porosities; however this largely depends on the reinforcing carbide particles in the Al-matrix.
Growth of Porous Alumina Layer and Cerium Sealing of Al7xxx/SiC Composite for Structural Lightweight Alloy Corrosion Resistant Application
Authors: Rizkia Vika , Munir Badrul , Soedarsono Johny Wahyuadi , Suharno Bambang , Rustandi Andi
Published: March 2014

AMC (Aluminum Matrix Composite) as a main material for automotive and aircraft applications has the keyadvantage that islighter thanaluminumalloys. So, it can be ascertained that fuel comsumption forthoseapplicationswill be reduced. However, AMC materials are generally suceptible to galvanic corrosion due to galvanic reaction between aluminum matrix and reinforcement, and the formation of microstructure at matrix/reinforcement interface as well. Anodizing is the most effective surface modification method in order to protect AMCs surfaces. This process produces porous anodic coating which has the characteristics of high corrosion resistance and hardness layer. However, the presence of reinforcement particles in AMC hinders the initiation and growth of the protective oxide layer by forming cavities and micro crack. Therefore cerium sealing has been done to remedy the poor anodic film in order to further enhance the corrosion resistance in aggressive circumstances.
The material studied in this research was AMC Al7xxx/SiC. Anodizing process were conducted in H2SO4 solution at current densities 15, 20, and 25 mA/cm2 at 0°C for 30 minutes. Subsequently, continuedwithelectro lesssealinginCeCl3.6H2O+H2O2 solutionat room temperature atpH9 for 30 minutes. The morphologies of anodic coating and sealing layer were examined by means of FE-SEM, the corrosion resistance of composites was estimated in a 3.5 wt.% NaCl solution by potentiodynamic polarization test.
Coating process conducted by anodizing and cerium sealing in various of anodizing current densities at 0°C results in protective layers which lead to the decreasing of corrosion rate and current density up to four orders magnifications than that of bare and anodizedAl7xxx/SiCcomposite.
Damage Size Classification of Natural Fibre Reinforced Composites Using Neural Network
Authors: Zaleha M. , Mahzan Shahruddin , Idris Maizlinda Izwana
Published: March 2014

Damage classification is considered as an important feature in pattern recognition, which led to providing significant information. This research work explores damage size classification for several impact events in natural fibre reinforced composites, which is based on the information provided by the ten piezoceramics (PZT) sensors. An Impact event produced strain waves which several data features were obtained through the response captured. An effective impact damage classification procedure is established using a multilayer perceptron neural network approach. The system was trained to predict the damage size based on the actual experimental data. The data features were mapped into five output class labels, presented as a target confusion matrix. The classification results revealed that the damage sizes were successfully mapped according to its respective class, with the peak to peak feature gives the highest classification rate at 98.4%.
Hydrothermal Synthesis and Photocatalytic Properties of BiPO4/Ag3PO4 Heterostructure for Phenol Decomposition
Authors: Sulaeman Uyi , Pratiwi Hesti , Riapanitra Anung , Iswanto Ponco , Yin Shu , Sato Tsugio
Published: March 2014

The heterostructures of BiPO4/Ag3PO4 were synthesized using a hydrothermal method with starting materials of Bi5O(OH)9(NO3)4, AgNO3 and Na2HPO4.12H2O at pH 1 under heating of 180°C for 12 h. The products were characterized using XRD, DRS and BET specific surface area. The photocatalytic activities were determined through the phenol decomposition under UV light (λ=390 nm) and blue light (λ=445 nm) irradiation. The heterostructures of BiPO4/Ag3PO4 with the body-centered cubic structure of Ag3PO4 and monoclinic of BiPO4 were successfully synthesized. The photocatalytic activity of BiPO4 under UV light irradiation could be enhanced by designing of BiPO4/Ag3PO4 heterostructure with the molar ratio of 0.75/0.25.
Wafer Extension for Cost-Effective Front to Back Side Alignment
Authors: Brabender S. , Kolander K. , Kallis K.T. , Fiedler H.L.
Published: March 2014

This work presents a cost-effective and simple possibility to outperform the potential of a standard single side mask aligner. The limited functionality is extended to the capability of back side alignment with minimal effort without additional knowledge and integration of new process technologies. The whole presented process flow performs without the necessity of additional equipment as infrared back side wafer alignment kits or additional etching processes or clamps and brackets. The result is a front to back side alignment process with satisfactory deviation.
Study of the Structural and Mechanical Properties of Nanocrystalline TiAlSiN Gradient Coatings
Authors: Cholakova T. , Chitanov V. , Chaliampalias D. , Kolaklieva Lilyana , Kakanakov R. , Bahchedjiev Ch. , Petkov N. , Pashinski Ch. , Vourlias G. , Vouroutzis N. , Polychroniadis E. , Wang Y. , Meletis E.I.
Published: March 2014

A study of the structural and mechanical properties of nanocrystalline TiAlSiN gradient coatings deposited by cathodic arc deposition techniques at 500 °C and post-annealed at 525 °C is presented. Analysis of the coatings, chemical composition and microstructure revealed that the coatings have a structure based on (Ti, Al)N nanocrystals with an average size of 10 nm embedded in an amorphous Si3N4 phase. The study of the mechanical properties showed that post-annealing causes improvement and increase of the coatings hardness. A maximum hardness of 48 GPa and elastic modulus of 560 GPa were measured. Also, excellent adhesion to the WC-Co substrate was observed in the post-annealed coatings.
Study of Memristive Elements Networks
Authors: Vourkas Ioannis , Sirakoulis Georgios Ch.
Published: March 2014

The existence of the fourth fundamental circuit element, the memristor, was first postulated over 30 years ago by Leon Chua. The implementation of the first modern memristor prototype by Hewlett Packard Laboratories in 2008 initiated a great scientific interest for these unique nanoelectronic devices and currently, there is a growing variety of systems that exhibit memristive behavior. However, most of the research has focused on the properties of the single devices, therefore very little is known about their response when these devices are organized into networks. In this work, the composite characteristics of memristive elements connected in network configurations are studied and the relationships among the single devices are investigated. We finally show how the threshold-dependent nonlinear memristive behavior could be elaborated to make possible the development of novel and sophisticated digital/analog memristive nanosystems.
Preparation of Fe2+-Doped Silica Sol and its Application in Silk Modification
Authors: Xing Tie Ling , Zhang Wei , Liu Zhi Juan , Tang Ren Cheng , Chen Guo Qiang
Published: March 2014

Fe2+ doped silica sol was prepared using tetraethoxysilane (TEOS) as precursor, ethanol as solvent, hydrochloric acid as catalyst and aqueous solution of ferrous iron by sol-gel method under the follow condition: [TEO:n [EtO:n [H2=1:6:11, reacted at 70°C for 120 min with stirring. Through characterization of the prepared silica sol using particle size analyzer, X-ray diffraction (XRD) and UV-visible spectrum, it could be concluded that even and stable silica sol with nanosize and color was prepared. The prepared Fe2+ doped silica sol was applied in silk modification to endow silk with multifunctional properties and color. X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM) indicated that Fe2+-doped silica sol was treated onto the surface of silk fabric. The results showed that the Fe2+ doped silica sol treated silk had good flame retardance, water repellence and antistatic property. At the same time, silk fabric treated by the Fe2+-doped silica sol was also endowed with color.
Determination of Material Acoustic Features Using Small Samples
Authors: Holub Jan , Desbos Bastien , Vacek Vítězslav , Kolisko Jiří
Published: March 2014

A new method to determine acoustic absorption in-situ is described in this paper. For practical consideration, this measurement can be performed on small samples (square of 60x60cm). This paper describes all the steps needed to obtain results: device setup, recording, signal processing.
Nanoindentation Derived Mechanical Properties of the Corneoscleral Rim of the Human Eye
Authors: Eberwein Philipp , Nohava Jiri , Schlunck Günther , Swain Michael
Published: March 2014

The corneoscleral rim of the eye represents a region with unique anatomical properties due to its location between the cornea and sclera / conjunctiva. It further has unique functional properties due to the location of adult corneal epithelial stem cells in the rim structure (limbus) itself. These stem cells are essential for the regeneration of the corneal epithelium and for preventing the conjunctival epithelium from growing onto the corneal surface, which could result in blindness. Survival and self-renewal properties of stem cells are known to depend on specific biological and biomechanical properties of its niche environment. We therefore aimed to measure the local mechanical properties of the human corneoscleral rim using a novel nanoindentation device (Bioindenter CSM Instruments, Neuchâtel, Switzerland) developed for soft tissues evaluation. Nanoindentation was performed using a spherical indenter of 0,5mm radius, a maximal load ranging between 20 μN to 30 μN and a penetration depth of several μm to 60μm. The hold period at maximum load was 180 seconds. Youngs modulus (E) was calculated using a Hertzian fit to the loading data. E of the central cornea was in the range of 19 kPa, while in the scleral region we found 17 kPa and the limbal rim region 10 kPa. Considerable creep relaxation occurred during the hold period at maximum load, which scaled with the elastic modulus of the different structures. These results reveal biomechanical properties of the corneoscleral rim with distinct mechanical properties for the three anatomical regions.
The Influence of Spraying Parameters on Stresses and Mechanical Properties of HVOF-Sprayed Co-Cr-W-C Coatings
Authors: Matějíček Jiří , Houdková Šárka , Bláhová Olga , Pala Zdenek
Published: March 2014

Stellite 6 Co-Cr-W-C coatings were sprayed by HVOF while systematically varying the spraying parameters, namely the equivalent ratio and combustion pressure. During spraying, the in-flight particle temperature and velocity were measured. Deposition, thermal and residual stresses were determined by in-situ curvature monitoring of the sprayed samples. Young's moduli and hardness of the coatings were determined by instrumented indentation. The relationship between spraying parameters, in-flight particle characteristics and mechanical properties is discussed.
The Influence of Indentation Conditions on Nanohardness Depth Profiles of W-C Based Coatings
Authors: Novák Michal , Lofaj František , Hviščová Petra
Published: March 2014

The influence of different indentation parameters including loading type, loading/strain rate, frequency and amplitude on nanohardness depth profiles on DC-MS W-C based coatings thick from 300 to 850 nm were investigated with the aim to determine the best conditions for the measurement of hardness of thin films during sinusoidal loading cycle. Nanohardness tests were performed on G200 (Agilent Technologies) and NHT (CSM Instruments) nanoindenters using standard loading/unloading cycle, CMC (continuous multicycle) mode and continuous stiffness measurement method (CSM) or sinus mode, respectively. The increase of strain rate and sinus amplitude results in decrease of maxima hardness of profiles while the increase of frequency caused its increase.
Hardness and Micro-Indentation Hardness Comparison of Recycled Modified HDPE
Authors: Navratil Jan , Manas Miroslav , Stanek Michal , Manas David , Ovsik Martin , Bednarik Martin , Mizera Ales
Published: March 2014

This research paper deals with the possible utilization of irradiated high-density polyethylene (HDPE) after its service life. Powder of recycled irradiated HDPE is used as filler into virgin low-density polyethylene (LDPE) in concentrations from 10 to 60 %. Two combinations of materials were tested granules LDPE/powder HDPE and powder LDPE/powder HDPE. Influence of the filler of the resulting blends on hardness and micro-indentation hardness was investigated. Shore D hardness test and instrumented micro-indentation hardness test were performed and results compared. According to the measured data both tested material characteristics are significantly influenced by the amount of the filler. Hardness increased with increasing amount of the filler at both material combinations; however results of micro-indentation test shows little inconsistency in hardness of surface layer.
Local Strain Hardening and Non-Uniformity of Plastic Strain of Tinplate
Authors: Slota Ján , Spišák Emil , Jurčišin Miroslav
Published: March 2014

During evaluation of the mechanical properties of tinplate for packaging industry by uniaxial tensile test, a non-uniform plastic strain occurs very often. This phenomenon results from the fact, that the plastic deformation is not uniformly developed throughout the measured section. There is a localization of deformation in one or more places resulting in local changes of the tinplate ́s mechanical properties. This paper deals with local strain hardening and non-uniformity of plastic strain of the tinplate temper TH415CA during uniaxial tensile test. Based on micro hardness measurements in the following locally deformed areas, local changes of mechanical properties of the tinplate were determined. The reasons of early strain localization were assumed by microstructural analysis. In the present work are considering partial aspects of the problem focusing on the properties of the local strain hardening and their consequences for stability of uniform plastic strain.
Inspection of Post Impact Fatigue Damage in Carbon Fibre Composite Using Modulus Mapping Technique
Authors: Koudelka Petr , Fíla Tomáš , Doktor Tomáš , Kytýř Daniel , Valach Jaroslav , Šepitka Josef , Lukeš Jaroslav
Published: March 2014

This study is focused on inspection of damage extent induced into C/PPS composite material by fatigue and impact loading. Initial damage to specimens was induced by drop-weight out-of-plane impact damage. Several levels of damage states (intact specimen, fatigued and impacted specimen, ruptured specimen) were inspected using modulus mapping (MM) technique. Quantification of the damage level was based on comparison of results from MM obtained in distinct locations on the specimens. Regions of interest were selected in order to determine magnitude of damage after impact and to assess remaining loading capabilities of the material. For this purpose, material maps provided information about location where matrix had been inflicted by the damage. Results show that impact loading has no measurable influence on mechanical properties of the matrix. However, gradient in mechanical properties was detected in the vicinity of crack. Results were validated using quasi-static nanoindentation and constant strain rate continuous measurement that showed depth profile of mechanical properties.
Evaluation of Fatigue Strength of Heat Treated and Laser Hardened 42CrMo4 Steel Considering Localized Initiation Mechanisms
Authors: Černý Ivo , Sís Jiří , Mikulová Dagmar
Published: March 2014

Laser surface hardening is an advanced method of surface treatment of structural steels with a great potential for wide industrial applications. According to the recent literature results and knowledge about laser hardening, fatigue resistance can be either reduced or increased, even considerably, depending on numerous parameters of basic material, the technology parameters etc. This contribution contains results of a partial study of effect of laser hardening of relatively small specimens on fatigue resistance of 42CrMo4 steel. Two different parameters of laser hardening were used, one of them resulted in considerable longitudinal residual stresses surface speed of laser beam 4 mm/s. Results of fatigue tests of basic reference material had a surprisingly high, atypical scatter, particularly in the region near fatigue limit. Fractographical analyses indicated that this scatter was connected with presence of single inclusions, even quite large, which in some cases caused fatigue crack initiation. Compressive residual stresses after the laser treatment improved fatigue strength and reduced the scatter, likely due to short crack retardation in the compressive residuals tress field. Further analyses and discussion are provided using Murakami method of fatigue life evaluation of materials containing defects.
In Situ Detection of Surface Micro-Cracking in Ultrafine-Grained AZ31 Magnesium Alloy by Resonant Ultrasound Spectroscopy
Authors: Seiner Hanuš S. , Sedlák Petr , Bodnárová Lucie , Landa Michal , Stráská Jitka , Janeček Miloš
Published: March 2014

Resonant ultrasound spectroscopy (RUS) was applied to monitor the micro-cracking process occurring during cooling at polished surfaces of an ultrafine-grained AZ31 magnesium alloy. It was observed that although the net of micro-cracks covered only narrow regions along the edges of the sample, its appearance resulted in a strong increase of the attenuation of the free elastic vibrations, and was, thus, sensitively detectable from the evolution of the RUS resonant spectra with temperature. This approach enabled a reliable determination of the threshold temperature for micro-cracking.
Cadmium Zinc Sulphide Nanoparticles as Sensing Material for Microcontroller Based Ammonia Sensor: Pilot Study
Authors: Haque M. Azimul , Mahalakshmi S. , Nanwal Ritesh
Published: March 2014

A microcontroller based sensor was designed for ammonia sensing. Cadmium zinc sulphide (CdZnS) nanoparticles were used as the sensing material. CdZnS nanoparticles were synthesized by chemical precipitation method. Synthesized CdZnS nanoparticles were characterized using X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) and Energy dispersive X-ray spectroscopy (EDS). CdZnS nanoparticles were deposited as thick films on glass substrate to act as gas sensor and its response to ammonia vapours was recorded using LabVIEW program interfaced with the microcontroller. The preliminary studies revealed that CdZnS nanoparticles can be used for ammonia sensing and the microcontroller based sensor design on proper calibration and integration can lead to the fabrication of a handheld sensor for sensing multiple parameters.
Self-Accommodating Nature of Martensite Formation in Shape Memory Alloys
Authors: Adiguzel Osman
Published: March 2014

Shape memory effect is a peculiar property exhibited by certain alloy system. This behavior is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of alloys; in particular, the morphology and orientation relationship between the various martensite variants. Martensitic transformation occurs in thermal manner, on cooling the materials from high temperature parent phase region. Thermal induced martensite called self-accommodated martensite or multivariant martensite occurs as multivariant martensite in self-accommodating manner and consists of lattice twins. Shape memory alloys are deformed in low temperature martensitic phase condition, and deformation proceeds through a martensite variant reorientation. Copper based alloys exhibit this property in metastable β - phase region.
Tungsten Carbide Decarburization by Electrical Discharges
Authors: Burkov Alexander Anatolyevich , Pyachin Sergey Anatolyevich
Published: March 2014

Electrospark deposition (ESD) was employed to clad WC-10%Co hard alloy on steel 1035 and the tribological properties of the coatings obtained were examined. The influence of the duration and frequency of discharges, the nature of the environment, and the carbon concentration in the electrode materials on the decarburization of tungsten carbide was studied. It is shown that the degree of tungsten carbide degradation can be reduced by decreasing the discharge frequency and increasing the concentration of carbon in the WC-Co electrode materials and also that the WC decarburization reaction is reversible on annealing.
Fabrication of Battery Cathode Material Based on Hydrolytic Lignin
Authors: Opra Denis P. , Gnedenkov Sergey V. , Sinebryukhov Sergey L. , Tsvetnikov Alexander K. , Sergienko Valentin I.
Published: March 2014

The relationship between the discharge performance of a lithium/hydrolytic lignin battery and the parameters of the cathode material fabrication process has been revealed. Electrochemical characterization was carried out using a galvanostatic discharge experiments. It was found that the specific capacity of hydrolytic lignin was found to be 600 mAh/g at a discharge current density of 45 μA/cm2. The results demonstrate the prospects of hydrolysis lignin-based batteries application as low-rate power sources.
Photorecording Polymeric Waveguide Film Based on 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2-dioksaborine for Photonics
Authors: Zhizhchenko Alexey Yu. , Kulchin Yuri N. , Vitrik Oleg B. , Mirochnik Anatoly G. , Fedorenko Elena V.
Published: March 2014

In this paper the possibility of using the novel polymeric photosensitive medium for the fabrication of integrated optics elements was demonstrated. The medium is based on PMMA doped by beta-diketonatoboron difluorides. Planar and strip waveguides with the attenuation losses less than 1.8 dB/cm were fabricated in the layer of the medium. The photoinduced recording of the diffraction grating with the spatial frequency up to 3000 mm-1and diffraction efficiency ~5% in such waveguides was demonstrated. The possibility to improve the diffraction efficiency of recorded gratings up to 51% by chemical treatment was demonstrated.
The Influence of Seed Layer on Growth of Magnetite Films on the SiO2/Si (001) Surface
Authors: Pisarenko Tatiana A. , Korobtsov Vladimir V. , Vikulov Viktor A. , Dimitriev Artem A. , Balashev Vyacheslav V.
Published: March 2014

Polycrystalline magnetite films with the thickness of 50 nm were grown on SiO2/Si(001) surface by the reactive deposition of Fe in O2 atmosphere using various preparation ways of the formation of iron oxide seed layer. The seed layers were formed by the deposition and oxidation of 3 nm Fe layer at different thermal conditions. It was found that polycrystalline magnetite films grown with the use of seed layer have [110] texture and are characterized by increase of the squareness of magnetic hysteresis loop. Structural analysis of magnetite films and predeposited seed layers was studied by RHEED.
Electron Spin Lifetime Control in GaAs Quantum Well by Means of Electrically Induced Lateral Traps
Authors: Larionov Andrey V. , Il'in Alexander I.
Published: March 2014

Experimental research has been made into coherent spin dynamics of electrons localized in GaAs quantum well planes using an electrically controlled potential. A localizing potential was created by means of a metal gate with submicron windows deposited on the sample surface. The photo-induced magneto-optical Kerr effect was used to study the dependence of electron spin lifetime as a function of temperature, applied bias and magnetic field for gates with various sets of windows. It has been shown that the electrically controlled laterally localizing potential can be used to smoothly vary electron spin lifetime from several hundreds of picoseconds to several tens of nanoseconds. The obtained dependence of spin electron relaxation time on the size of the lateral localization region is in good qualitative agreement with the theoretical prediction.
Morphology of Emiliania huxleyi coccoliths on the North West European shelf – is there an influence of carbonate chemistry?
Authors: Young J. R. , Poulton A. J. , Tyrrell T.
Published: March 2014

Abstract. Within the context of the UK Ocean Acidification project, Emiliania huxleyi (type A) coccolith morphology was examined from samples collected during cruise D366. In particular, a morphometric study of coccolith size and degree of calcification was made on scanning electron microscope images of samples from shipboard CO2 perturbation experiments and from a set of environmental samples with significant variation in calcite saturation state (Ωcalcite). One bioassay in particular (E4 from the southern North Sea) yielded unambiguous results – in this bioassay exponential growth from a low level occurred with no artificial stimulation and coccosphere numbers increased ten-fold during the experiment. The samples with elevated CO2 saw significantly reduced coccolithophore growth. However, coccolithophore morphology was not significantly affected by the changing CO2 conditions even under the highest levels of perturbation (1000 μatm). Environmental samples similarly showed no correlation of coccolithophore morphology with calcite saturation state. Some variation in coccolith size and degree of calcification does occur but this seems to be predominantly due to genotypic differentiation between populations on the shelf and in the open ocean.
Measures to Increase Recoveries and Avoid Concentrate Disposal: Principles to Control Scaling and Reduce Concentrate Disposal in Reverse Osmosis Applications
Authors: Pervov Alexei
Published: March 2014

The present work is aimed at development of a new approach to reduce RO concentrate flow and to increase recovery. The described techniques enable us to remove calcium carbonate from RO concentrate by means of "seed" сrystallization. These proposed techniques use "open channel" spiral wound membrane modules that can directly treat water with high scaling and fouling potentials without pretreatment. The experimental procedure is described and experimental plots are presented that describe precipitation kinetics. The test membrane unit was operated in circulation mode and recovery values reach 95% or higher. RO concentrate constantly passed through the precipitation reactor where seed crystals were contained. Seed crystal formation was initiated by injecting caustic solution to RO concentrate. The driving force for crystal growth was constantly created by RO process due to increase of calcium and carbonate ion concentration values.
Fouling control is achieved by providing sufficient cross flow velocities, flushings and cleanings. Coagulated suspended matter after membrane flushes is collected, sedimented and finally dewatered. The concentrated solution that contains rejected salts and impurities constitutes no more than 1 per cent of initial feed water volume and can be withdrawn together with wet sludge as a sludge moisture. The described technical procedure enables us to completely utilize concentrate and produce quality product water, softened water and sludge.