bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Solvent System and Polymer Concentration for Synthesis of Polyvinyl Alcohol (PVA) Fiber Using Rotary Forcespinning Technique
Authors: Munir Muhammad Miftahul , Fauzi Ahmad , Nuryantini Ade Yeti , Nursuhud Nursuhud , Sofiari Eri , Khairurrijal Khairurrijal
Published: August 2015

Rotary forcespinning is one of techniques used for fabrication of polymer fiber. In this paper optimization of several parameters for synthesis of Polyvinyl Alcohol (PVA) fiber using rotary forcespinning technique was described. In order to obtain PVA fiber with smallest diameter the optimization parameters of solvent system and polymer concentration were performed. The results show that PVA dissolved in water as a single solvent produced fiber with high wettability. A mixture of water and ethanol as a solvent system was developed with variation in ethanol content. The effects of ethanol content on fiber diameter were investigated. Rotary forcespinning using solvent with ethanol content below 30% resulted in PVA fiber with high wettability, while solvent ethanol content of more than 70% was unable to dissolve PVA completely. The effect of PVA concentration on the fiber morphology was investigated by adjusting PVA concentration in the range of 9 to 13 weight %. The diameter of the PVA fiber was uniform and could be controlled by adjusting the PVA concentration.
Evolution of ZnO Nanoflower-Like Structure Formation and Growth during Synthesis and Paste Preparation
Authors: Iqbal Muhammad , Mahendra Robert , Wahyuono Ruri Agung , Sawitri Dyah , Risanti Doty Dewi
Published: August 2015

ZnO nanoflowers were synthesized by co-precipitation method at low temperature (80°C) for dye-sensitized solar cell applications. ZnO nanostructures were grown at various pH values from Zinc nitrate tetrahydrate [Zn (NO3)2.4H2O], HMTA (Hexamethylenetetramine) and Potassium Hydroxide (KOH). The results indicate that by increasing pH from 6 to 12, the ZnO morphology evolves from aggregrated particles, prism-like and eventually flower-like structures. According the Scherrer equation the particle size of (100), (002), and (101) peaks tends to drop as the pH increased. HMTA is known as an effective reductant to produce hexagonal ZnO rods of various lengths and cross-sections. Low HMTA led to smaller petal and further addition caused the petal became wider. Annealing temperature should not be higher than 200°C.
Effect of Temperature on Silver Nanorods Synthesized by Polyol Method
Authors: Junaidi Junaidi , Triyana Kuwat , Sosiati Harini , Suharyadi Edi , Harsoyo Harsoyo
Published: August 2015

Effect of temperature on the formation of silver nanorods (AgNRs) synthesized using polyol method has been investigated. In this experiment, materials were used silver nitrate (AgNO3) as main raw material, ethylene glycol (EG) as a solvent, small amount of sodium chloride (NaCl) as a mediated agent, while polyvinyl alcohol (PVA) as a capping agent to assist the growth of AgNRs. To apply a constant temperature at each synthesis process, an Erlenmeyer flask containing the sample was immersed in a controllable magnetic stirrer oil bath. It is found that the presence of heat as represented by the temperature of oil bath has been shown to have a strong impact on the AgNRs formation. The scanning electron microscope (SEM) confirmed uniform and high density of AgNRs when the oil bath temperature during polyol process was 140 °C. In the same condition, the UV-vis spectra also confirmed formation process of AgNRs with appearance of the transverse plasmon peak about 350 nm. Finally, the X-ray diffraction (XRD) pattern represented that the final product of AgNRs was highly crystallized.
Influence of Grain Size to Resistivity Relaxation of La0.7Sr0.3MnO3 Nanoparticles
Authors: Naa Christian Fredy , Fasquelle Didier , Mascot Manuel , Suprijadi Suprijadi , Viridi Sparisoma , Djamal Mitra
Published: August 2015

The resistivity relaxation in magnetic material is one of the important characteristics for reliable device operations. It also provides insight to the physics of magnetic material. Furthermore, this characteristic is related to the micro structural of the material. In this paper, the resistivity relax- ation of different grain sizes of La0.7Sr0.3MnO3 (LSMO) nanoparticles has been studied. The LSMO nanoparticles was synthesized by sol-gel method and to obtain different grain size, the samples were sintered at different temperatures ranging from 800◦C to 1100◦C. The resistivity relaxation measurements were recorded for 500-1500s under the influence of magnetic field in range 25-110mT in room temperature. Under the influence of magnetic field, the resistivity of all samples were slowly de- creases as a function of time following logarithmic behavior. Moreover, no saturation was observed in the measurement time span. The resistivity ratio ρ(t)/ρ(0) as a function of time t was fitted by using logarithmic model. It is shown that resistivity relaxation depends on the grain size and the strength of the magnetic field.
Fabrication of Poly(acrylonitrile)/PAN Nanofiber Using a Drum Collector Electrospinning System for Water Purification Application
Authors: Munir Muhammad Miftahul , Prama Ekaputra Muhamad , Rajak Abdul , Rahma Annisa , Nuryantini Ade Yeti , Khairurrijal Khairurrijal
Published: August 2015

The development of filtration technique for water purification has been performed ranging from the conventional to the advanced technique such as coagulation, sedimentation, sand filtration, reverse osmosis and nanofiltration. However, the major challenge to be addressed in the filtration technique is the tendency of membrane fouling or clogging. This effect causes a decreasein the flux and effectiveness of membrane filtration. In this study, we reported the fabrication of poly (acrylonitrile)/PAN nanofiber membrane by electrospinning technique and their application for water purification. A drum collector electrospinning system was used to produce uniform nanofiber membrane. Nanofiber membrane was fabricated from precursor solution which was prepared by dissolving poly (acrylonitrile) that has molecular weight of 150.000 g/mol in n,n-dimethylformamide (DMF). PAN nanofiber membrane were fabricated via electrospinning technique with 8wt% in concentration. The morphology of the membrane was characterized by using Scanning Electron Microscopy (SEM). SEM analysis showed that uniform nanofiber was formed with average fiber diameter of 290-370 nm. Three different concentrations of antacid suspension were prepared as the sample in order to test the performance of PAN nanofiber as membrane filter. Flux test was carried out by applying various pressure against the membrane in order to obtain the flux values of each variation of waste water model. The purity of the filtrate was analyzed by using UV spectrophotometer and the result show a decreased absorbance by 93%.
Photocatalytic Degradation of Methylene Blue Using TiO2/Carbon Nanoparticles Fabricated by Electrical Arc Discharge in Liquid Medium
Authors: Saraswati Teguh Endah , Andhika Isya Fitri , Patiha Patiha , Purnawan Candra , Wahyuningsih Sayekti , Anwar Miftahul
Published: August 2015

Herein we modified TiO2 anatase with carbon material using an electrical arc discharge technique in liquid medium to produce a nanoparticle of TiO2/Carbon photocatalyst. The electrical arc discharge was performed using two graphite electrodes submerged in TiO2 suspended in ethanol by passing electrical 20-40 V (10-50 A). X-ray Diffraction (XRD) peak profile analysis shows the successful modification confirmed from the presenting peaks which represent to crystalline TiO2 and carbon element. The fabrication was then followed by the assessment of photocatalytic activity of fabricated nanoparticles in methylebe blue degradation under mercury lamp irradiation. After 60 minutes irradiation, the photocatalytic activity of TiO2/Carbon increased more than three times higher compared to the photocatalytic activity of pristine TiO2.
Photocatalytic Degradation of Methylene Blue and Methyl Orange with Fe-Doped ZnO Nanoparticles Modified with Natural Zeolite and Montmorillonite: Comparative Study
Authors: Afifah Nur , Adriani Siti , Djaja Nadia Febiana , Saleh Rosari
Published: August 2015

The present study compares the photocatalytic decolorization ability of Fe-doped ZnO modified both natural zeolite and montmorillonite towards aqueous solution of organic dyes such as methylene blue and methyl orange under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray, Fourier-transform infrared absorption, and electron spin resonance spectroscopy. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to natural zeolite.
Reducing Energy Consumption through Innovative Glass Layering Construction with Polyethylene Bubble Wrap at 2nd Floor Dean Faculty Room
Authors: Putra Ary Bachtiar Krishna , Widyastuti Widyastuti , Anton Dimas , Safitra Arrad Ghani , Novianarenti Eky
Published: August 2015

Reducing energy consumption in buildings has been an important and growing concern in most countries since the Kyoto Protocol was entered into force in 2005. For instance, ITS has set the target reduction of greenhouse gases in building and support act as a legal framework for promoting ECO Campus program. Design concept using glass layering construction with bubble wrap can contribute significantly in reducing the required air conditioning system size so annual energy cost decrease too. The objective of this paper is to present an overview of the basic principles of thermal insulation, the example of building energy modeling using polyethylene insulation materials, and to survey the most commonly used building insulation materials as well as their performance characteristics. A “bubble wrap” with a reflective insulation helps to reduce heat loss by reflecting away up to 97% radiant energy with less than 0.05 emittance. The result from this study is 3% to 6% annual energy savings was cited.
Potential Implementation of Electronic Waste Based Magnetite Powder for Magnetorheological Elastomers
Authors: Ubaidillah Ubaidillah , Yahya Iwan , Harjana Harjana , Mazlan Saiful Amri , Sutrisno Joko , Zamzuri Hairi
Published: August 2015

This paper focuses on the preliminary characterization of alternative magnetic particles as a replacement for commercial carbonyl iron particles for magnetorheological elastomers (MREs). Magnetite powder (Fe3O4) can be found in electronic waste (E-waste), iron ore as well as toner waste. In this study, three types of powders namely electronic waste based ferrite powder, iron sand, and toner waste are characterized according to their size and morphology (SEM), chemical elements (EDAX), chemical compound (XRD) and magnetic properties (VSM). The results are used as considerations to choose the most suitable powders that could replace carbonyl iron. The average size of all powders types is about 1 to 50 microns and having irregular shapes. The highest content of magnetite (Fe3O4) compound is found in electronic waste based ferrite powders by referring to magnetite patterns (reference code: JCPDS 01-088-0315). Electronic waste based ferrite powder has the highest magnetic moments saturation of 92.9 emu/g compared the counterparts. Finally, electronic waste based ferrite powder appears to be the most potential materials for replacing the carbonyl iron.
Investigation on the Elastic Modulus of Rubber-Like Materials by Straight Blade Indentation Using Numerical Analysis
Authors: Setiyana Budi , Wicahyo F.D. , Ismail Rifky , Jamari J. , Schipper Dirk Jan
Published: August 2015

The indentation technique has been proven to be useful in determining mechanical properties of materials, but it is rarely applied to rubber-like materials (elastomers). It is difficult to describe accurately the mechanical properties of an elastomer by theoretical formulation due to its complex material behaviour. Indentation of a Styrene Butadiene Rubber (SBR-0) material by a rigid straight blade with a tip angle of 45 and 60 degrees was performed to estimate the elastic modulus. Indentation was carried out numerically by finite element analysis (FEA) and for the elastomer the hyper-elastic material model of Mooney-Rivlin is used. The estimated elastic modulus was calculated based on the contact depth. The predicted result was also verified by tensile test results. It was found that the predicted elastic modulus of the elastomer agrees with the tensile test result.
Processing and Superelasticity of Ni-Ti Shape Memory Alloys
Authors: Dobrescu Mircea , Vasilescu Marius
Published: August 2015

In the paper is shown the study of super elasticity of Ni-Ti shape memory alloys from the point of view of stored energy, strain dependencies and martensitic transformations that influence superelasticity of Ni-Ti shape memory alloys [1]. We also present the influence of temperature and alloy composition on the properties of Ni-Ti alloys after plastic deformation and heat treating [2].
Researches Regarding the Influence of Technological Parameters on the Alloying Efficiency in Powder Injection Process
Authors: Geantă Victor
Published: August 2015

The injection of the powdered materials into molten melts is a common practice in the metallurgical technology of steel refining and alloying. During process development, within the metal bath is formed a mixed three-phase with different structures depending on the parameters of the hydrodynamic injection. The “plume zone” represents a domain inside of the molten metal in which takes place the forming, coalescence and disintegration of the gas bubbles, that penetrate into the molten metal together with the powdered material. The “plume zone” is the primary contact zone between the powdered particles and the molten metal. Inside of contact zone is take place the chemical reactions between the reactive material and the metal bath components. The “plume zone” size, shape and structure are functions of the hydrodynamic parameters of the injection process, the most important being the injection speed. The size of this parameter leads at the appearance of a multitude of possible structures types of the metal bath. These structures dictate the metallurgical process efficiency in defining the steelmaking process and refining of metal bath. In the present paper are investigated and discussed the “plume zone” structures formed during injection with graphite particle of a molten steel bath and the metallurgical results obtained experimentally under the influence of the injection velocity.
Review on the Application of Natural Fiber Composite via Filament Winding Using Different Resin
Authors: Ansari Suriyati Mohamed , Ruzaidi Che Mohd , Husin Kamarudin
Published: August 2015

Even though synthetic fiber give higher of strength in composites and is low cost material, the biggest problems faced when using this material is that it does not degrade or compose in the environment. The usage of natural fibers in industrial application become the main concern because it offer both cost savings and a reduction in density when compared to existing fibers such as glass fibers and etc. This make the needs for renewable fiber reinforced composites are increasing and have never been as prevalent as it currently is. Although the strength of natural fibers is not great as glass, the specific properties are comparable. Continuous yarn fibers are required to increase the strength for engineering applications and filament winding is a method to produce aligned technical composites which have high fiber content. This paper presents a review on composites made of natural fiber and different resin that been processed via filament winding technique.
Sol Gel Synthesis and In Vitro Evaluation of Apatite Forming Ability of Silica-Based Composite Glass in SBF
Authors: Syed Adam Syed Nuzul Fadzli , Roslinda S. , Zainuddin Firuz
Published: August 2015

In this study, xerogel glass based on SiO-CaO-PO4 was synthesized by a low temperature acid catalysed sol-gel route. The in vitro evaluation of apatite forming ability for the glass was conducted in simulated body fluid (SBF) solution as the glasses were immersed for duration of 1, 7, 24 hours and 7 days. The XRD analysis showed that the glass formed semi-crystalline structure when sintered at 1000oC and consisted of Ca2O7P2 and Ca2O4Si phases. Image captured using FESEM showed the apatite-like structures were eventually formed on the glass top surface in small numbers after the glass immersed in SBF for only an hour. The numbers of the apatite structures were continuously grown with the increase period of immersion time. The apatite structure mostly covered on top of the glass surface after 24 hours of immersion and continuously growth into bone-like apatite structure when immersed for 7 days in the SBF. The apatite layer formed on the surface of the glass was confirmed as crystalline structure of hydroxyl-carbonate-apatite (HCA) as revealed by the complimentary results of EDS, XRD and FTIR analysis.
The Effect of Storage Time on the Composition of the Olive and Sunflower Oils
Authors: Cobzaru Claudia , Bordeianu Genoveva , Marinoiu Adriana , Apostolescu Gabriela Antoaneta , Cobzaru Cristina , Tataru-Farmus Ramona Elena , Ungureanu Doina , Cernatescu Corina , Apostolescu Nicolae
Published: August 2015

The effect of storage time on the composition of the olive and sunflower oils has been investigated. It were studied parameters like free fatty acids (FFA), anisidine value (AV), iodine value (IV), saponification number (SN) and identification of the molecular structure through FT-IR method. During storage (48 months) an increasing in the values of parameters FFA and AV took place that measures the oxidative degradation of oils. The oxidative stability of olive oil stored at room temperature was less than of sunflower oil. Also, significant differences were found among the olive oil and sunflower oil during storage period.
Thin Films Based on Tungsten Carbide with Binary, Ternary and Quaternary Composition, Obtained by Magnetron Sputtering
Authors: Mateescu A.O. , Mateescu G. , Bălan A. , Stamatin I. , Jinga Vlad , Samoila Cornel , Ursuțiu Doru
Published: August 2015

Tungsten carbide is an anorganic compound with very interesting tribology features such as: the highest melting point and hardness values among the known compounds, high elasticity (Young) modulus, high thermal stability on a large temperature range, low chemical reactivity, etc. Magnetron sputtering is the most convenient deposition method for obtaining tribological coatings with binary/ternary/quaternary composition starting from WC commercially magnetron sputtering targets. Roughness and grain size of such coatings were investigated by Atomic Force Microscopy and electrical sheet resistance was investigated by using the Four Point Probe Method with ALESSI head and W electrodes.
Assessment of Synthetic Quenching Media for Hardening
Authors: Perju Manuela Cristina , Tugui Catalin Andrei , Nejneru Carmen
Published: August 2015

For a number of methods used in the cooling heat treatment technique, are required quenching media with cooling rate lower than that of water and larger than that of oil. This can be achieved in industrial practice by using the synthetic quenching type media like gels or emulsions. The synthetic quenching coolants offer advantages such as non-flammability, safety of use and low cost price. The cooling medium to be tested is emulsifiable oil dissolved in water at various concentrations and the testing temperature is 50°C. In the paper were measured cooling curves for specified synthetic media and calculated for the same media the cooling rate variation and heat transfer coefficient on intervals. The experimental data were compared with those obtained from traditional media: water and heat treatment oil TT 50.
Laboratory Investigations for Strength Grading of Spruce Timber Elements
Authors: Isopescu Dorina Nicolina , Neculai Oana
Published: August 2015

The paper presents the results of experimental tests and the process by which a batch of spruce timber elements is sorted in a strength class with reliability.
Non-Destructive Vibration Tests on Reinforced Concrete Structures
Authors: Lute Marina
Published: August 2015

The purpose of this paper is looking at the dynamic response of existing reinforced concrete structures which have possibly sustained various levels of damage, a set of tests need to be identified that will be able to detect damage and quantify the damage if damage exists. In this work it is presented a further study on the effect of damage on the behavior of reinforced concrete beams. In particular, the non-linear behavior of these beams is considered once significant cracking has been introduced, outlining the stage of testing carried out in dynamic field.
Thermal Studies of Specific Envelope Solutions for an Energy Efficient Building
Authors: Boros Iosif , Tanasa Cristina , Stoian Valeriu , Dan Daniel
Published: August 2015

This paper presents the design and monitoring scheme of an energy efficient high school building with emphasis on the analysis of constructive and geometric thermal bridges that can affect the overall energy consumption and thermal comfort. The ANTHERM software is used to accurately assess the specific details and determine isotherms, heat flux distribution and the Psi-values (Ψ value) of the sections where different types of materials connect. A monitoring system with temperature sensors installed in the layers of the building envelope elements has been designed in order to compare the obtained values with the real time thermal performances of the envelope elements. The study highlights the influence of the type and thickness of the insulation materials used in the specific constructive details on the overall thermal performance of buildings.
A Holistic Approach to a Sustainable Steel Building
Authors: Campian Cristina , Chira Nicolae , Pop Maria
Published: August 2015

Impacts of production, operation and use of a building on the environment and society cannot be ignored in design any more. Instead, performance and impacts of a building needs to be considered for a lifetime, established by design rules 50-100 years. Steel, as constructional material, plays an important role as a component for buildings and engineered structures, with a wide range of applications. Like other industrial activities, steel industry works continuously to improve in terms of sustainability. In fact, in can be observed that in the last decades, the steel frames houses, as an alternative to houses made of traditional materials, offers a lot of advantages in terms of sustainability. The approach in term of a life cycle for a building is an objective process for the evaluation of the impact on the environment, associate to a production process or to an activity. These approaches are recommended by the Integrated Product Policy (COM2003) for the evaluation of the potential impact of the products In present, there are 2 majors categories instruments for the evaluation of the built environment, on one hand made on qualitative instruments based on criteria and score, and on the other hand instruments that use an quantitative analyze of the inputs and outputs based on a life cycle. Some of these methods are used for the certification of buildings as “green-buildings”. Even many parameters are usually quantitative; they can be also qualitative in the same time, when we try to quantify the advantages due to materials.
Chemical Deposition of Thin Layers on Reinforcing Steel
Authors: Lazăr Petru , Bejinariu Costică , Sandu Andrei Victor , Cazac Alin , Sandu Ioan Gabriel
Published: August 2015

This paper presents the results of experimental research on the influence of using microcrystalline phosphating process on the OB37 steel used in construction. For this purpose, the samples were immersed in phosphate solution and the structures were characterized using SEM microscope. The results show that the obtained structures, are influenced by pH and immersion time and show a good surface compactity and roughness, which means that the obtained layer on the OB37 reinforcement improves corrosion resistance and adhesion of these reinforcements in the reinforced concrete.
Ballasted Track versus Ballastless Track
Authors: Köllő Szabolcs Attila , Puskás Attila , Köllő Gavril
Published: August 2015

First concrete sleepers were made of normal reinforced concrete and used during the 1930s and 1940s. Concrete railroad ties became popular in Europe after World War II because of the advances in design, material quality and production of pre-stressed concrete. Now as before, concrete sleepers on ballast represent the primary basis of track construction, around the world, but the twin block concrete sleepers are also popular and widely used. The continuously increasing operational loads and speeds forced the railway companies to update their technical and economic system to keep their vital role in transporting passengers and merchandise. In this development a very important role played the superstructure of the railroad system, and this modernization process led to appearing of the ballastless track system approximately 60 years ago. The article presents a comparison of two main types of track systems, including technical and economic aspects.
The Effect of Solid-to-Liquid Ratio and Temperature on Mechanical Properties of Kaolin Geopolymer Ceramics
Authors: Ahmad Romisuhani , Al Bakri Abdullah Mohd Mustafa , Kamarudin Hussin , Sandu Andrei Victor , Binhussain Mohammed , Ahmad Mohd Izzat , Jaya Nur Ain
Published: August 2015

The effect of solid-to-liquid ratio and temperature on the mechanical properties of kaolin geopolymer ceramics are studied. Kaolin and alkaline activator were mixed with the solid-to-liquid ratio in the range of 0.8-1.2. Alkaline activator was formed by mixing the 12 M NaOH solution with sodium silicate at a ratio of 0.24. Kaolin geopolymer ceramic have been produced by using powder metallurgy (PM) technique. The samples were heated at different temperature started from 900 °C until 1200 °C and the strength were tested. The relative density and flexural strength of sintered sample range approximately 84%-95% and 20-90 MPa respectively. The result revealed that the optimum flexural strength was obtained at solid-to-liquid ratio of 1.0 and the samples heated at 1200 °C achieved the highest flexural strength (90 MPa).
Study Concerning the Thermal Insulation Panels with Double-Side Anti-Condensation Foil on the Exterior and Polyurethane Foam or Polyisocyanurate on the Interior
Authors: Pescari Simon , Tudor Dan , Tölgyi Stefan , Maduta Carmen
Published: August 2015

The paper aims to assess the energy performance of a thermal rehabilitated ground floor building by using new thermal insulation panels with double-side anti-condensation foil on the exterior and polyurethane foam or polyisocyanurate on the interior (PUR or PIR) in various ways. The study also wants to emphasize the benefits of using these insulating materials encouraging their further use. Therefore, five scenarios are carried out, four thermal rehabilitation scenarios and the reference building scenario, without thermal insulation. The obtained results are evaluated by comparison. The results point out the energy performance of PUR and PIR used as thermal insulation panels for the building envelope but also the economic impact and the economic efficiency that involves using such panels. This work is based on the energy efficiency requirements targeting the building envelope and takes into account mainly the behavior of the envelope elements while the heating system is treated in a simplified manner, considering its usual efficiency. The conclusions highlight the main advantages of using these panels for buildings thermal rehabilitation compared to other common materials, such as polystyrene or mineral wool.
A Review – Manufacturing on Rubberized Concrete Filled Recycled Tire Rubber
Authors: Azmi Ahmad Azrem , Al Bakri Abdullah Mohd Mustafa , Ghazali Che Mohd Ruzaidi , Sandu Andrei Victor , Kamarudin Hussin
Published: August 2015

This paper aims to investigate the potential use of recycled tire rubber in concrete. In Malaysia, rubber consumption of tires in January – June 2014, rose up to 8.4% from 0.388 million tonnes. These numbers keep on increasing year-over-year with the numbers of vehicles, as do the future problems relating to waste tires. Over the past few years, a number of researchers have studied on incorporated the waste tires into cement based materials. In an attempt to reduce the magnitude of this issue, recycled tire rubber has gained interest in concrete improvement. The used of recycled tire rubber in the reinforcement in concrete is considered as value added materials for sustainable development by reusing waste materials. It is believed that using waste tire rubber in concrete could be an alternative way to replace fine and coarse aggregate (sand and gravel) in improving the properties of concrete. Rubberized concretes can be used in architectural applications such as side walk pavement, nailing concrete, in road constructions where high strength is not necessary, outdoor playground mat, in wall panels that require low unit weight, in sound barriers as sound absorbers, and in railroads to fix the rails to the ground.
The Recycling of Materials - From Green Marketing Strategy to the Need for Sustainable Development in Contemporary Society
Authors: Luca Florin Alexandru , Filipeanu Dumitru , Ioan Corina Anamaria
Published: August 2015

Sustainable development becomes a desiderate increasingly important, both for policy makers and for manufacturing companies. Behind this concept, however, there are a number of factors and strategies covering topics from the education of population from an ecological point of view and legislative stipulations designed to influence the management of all resources. In this context, strategies arising from the private greenmarketing are completing the coercive force of European legislation.
Layered Double Hydroxides (LDHs) Type Materials Used in Water Treatment
Authors: Nichitus Simona , Calin Gabriela , Burlui Alexandra , Stadoleanu Carmen , Burlui Vasile
Published: August 2015

Layered double hydroxides (LDHs) or LDHs matrices used for water treatment have been reviewed in this article. These aggregated nanoparticles can be obtained by sol-gel, hydrothermal or coprecipitation method, therefore their shape, size, properties (such as magnetic, acido-bazic, red-ox, texture and assembly) and applications are tailored as a function of synthesis method and process parameters respectively. Among other materials used in water treatment we chose layered double hydroxides generally named LDHs or in particular case hydrotalcites (MgAlLDHs). During calcination layered structure is destroyed giving rise to new structures like mixed oxides partially crystallized. LDHs and calcined LDHs type materials were able to uptake selected products. An important issue for removal of undesirable species for human health was M2+/M3+ cation ratio. Results show a better uptake of anionic compounds for thermally activated LDHs due to their “memory effect”. A large variety of LDHs was investigated in order to demonstrate their adsorption capacity for anionic compounds, cations, gas compounds even microorganisms. Nowadays one of the atractive issues of nanoscience is both the synthesis of these nanostructures and the assembly and organization way but the interest of scientists is to find new properties and applications in order to protect the environment. These cost effective, eco-friendly materials revealed new opportunities for waste water treatment.
The Electrical Resistivity of Geopolymer Paste by Using Wenner Four Probe Method
Authors: Zainal Farah Farhana , Kamarudin Hussin , Rahmat Azmi , Abdullah Mohd Mustafa Al Bakri , Rizam Shaiful , Selimin Mohammad Tamizi , Sandu Andrei Victor
Published: August 2015

This paper presents an experimental study of the electrical resistivity of geopolymer paste by using a non-destructive test employing Wenner four probe method. Geopolymer is produced from a combination mixture of aluminosilicate materials which is rich in Si and Al such as fly ash with an alkaline activator. Geopolymer paste in this study was made from a mixture of class F fly ash, sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solution. An alkaline activator was prepared 24 hrs prior to use with the ratio mixture of Na2SiO3/NaOH being 2.5. Then, the prepared alkaline activator was mixed with the fly ash for about 30 minutes. After that, the mixture was placed in a 100 mm x 103 mm x 495 mm mould. After 24 hrs, the sample was taken out from the mould and cured at 60°C in the oven for 24 hrs. The sample was then tested after 7, 14 and 28 days. The current applied in this study was from 0.01 mA to 1.00 mA and the electrode spacing used were 0.02 m, 0.04 m, 0.06 m, 0.08 m and 0.10 m. The results showed that the geopolymer paste after 28 days with the current of 0.01 mA and 0.10 m electrode spacing showed the highest resistivity with 61575 Ω.m while the geopolymer paste after 7 days with 0.95 mA and 0.02 m electrode spacing showed the lowest resistivity with 537 Ω.m. Hence, the corrosion rate of geopolymer paste in this study was negligible and if occur, was very low.
Synthesis of Alum from Discarded Aluminium Beverage Cans
Authors: Liew Yun Ming , Heah Cheng Yong , Al Bakri Abdullah Mohd Mustafa , Kamarudin Hussin
Published: August 2015

This study provides a chemical process that recycles waste aluminium cans to alum crystals that has plenty applications in industry today. The study was performed with concentrated acidic and alkaline solution containing principal components K+ and SO42- ions. It involved the dissolution of aluminium can in KOH solution, neutralization by H2SO4 solution and cooling crystallization to produce alum crystals. Emphasis was placed on the percentage yield of alum and recovery of aluminium from waste aluminium can to useful product. The result obtained the highest yield of 80% when 1.5M of KOH solution and 9M of H2SO4 solution were used with 5 g of aluminium beverage cans. When the concentration of KOH and H2SO4 solution was increased, the yield of alum production was also increased. It was found that the crystallization process was effective in recovering aluminium in the form of alum from waste aluminium beverage cans.
A Review on Processing and Properties of Bottom Ash Based Geopolymer Materials
Authors: Deraman Laila Mardiah , Al Bakri Abdullah Mohd Mustafa , Liew Yun Ming , Kamarudin Hussin , Zarina Yahya
Published: August 2015

Geopolymerization are chemical reaction between raw material and alkaline activator where a rapid change of some partial armorphous, specific structure into a compact cemented framework. It was treated with an alkali silicate solution at 45 – 80 °C whereas it’s formed from reaction of mineral clays or aluminosilicate-bearing industrial waste. The previous study about geopolymer has been done for many years due to the physical and chemical properties which is suitable to use in the construction industry. A Geopolymer material that was containing most Silica (Si) and Aluminium (Al) is such as fly ash, bottom ash, metakaolin and ground granulate blast slag (GGBS). Bottom ash is produced from coal fired thermal power plant and has a physical characteristic similar as sand or gravel sand that makes it ideal for industrial application like a green concrete. The different performance of geopolymer is according to the different content of silica, alumina and calcium. To obtain the best geopolymer material, parameter of raw materials content, the types and ratio of alkaline activators also the curing method will affect the high result of compressive strength. This paper will summarize a previous researchers work about the alkali-activated binder in geopolymer raw materials to become green product.
Determination Performance of Thermoacoustic Heat Engine Simulation by Delta EC Software
Authors: Abd Rahim Irfan , Mohd Zain Mohd Zarhamdy , Asmuin Norzelawati , Mohd Saad Mohd Sazli
Published: August 2015

Thermoacoustic Heat Engine probably the most efficient energy source for electronic devices for the next 10 year ahead that require small amount of electrical energy to operate. This study was to simulate the Thermoacoustic Heat Engine (TAHE) standing wave system by conducting a Fluid Structure Interaction (FSI) by using a Thermoacoustic system’s software named DeltaEC for better uderstanding on the fundamental of TAHE standing wave system. Some characteristics or parameters in the system that were studied in order to derive the fundamental knowledge of TAHE standing wave system. The thickness of Hot Heat Exchangers (Hot HX) plays the major role in affecting the maximum acoustic power generated, the level of onset temperature difference and maximum pressure amplitude followed by the stack length. Hot HX dimension (thickness) contributes nearly 3.3% changes in maximum acoustic power where the lowest thickness scores the highest maximum acoustic power generated. 2.9% of increment on maximum acoustic power generated by altering the length of the stack by 5 mm.
Elements of Modeling and Simulation for Piezoelectric Motors
Authors: Nitan Ilie , Milici Laurentiu D. , Milici Mariana R. , Cernomazu Dorel
Published: August 2015

In order to obtain a high rotational speed in comparison with the known embodiments, due to the increased amplitude of the contact point between the rotor and the active element, due to the possibility of adjusting the speed by changing the frequency of the two signals applied to the coupled discs, or due to the phase shift between the signals if the discs are supplied at the same frequency, it was achieved a stator by a non-removable coupling of two active elements. Modelling was performed in Comsol Multiphysics. In this respect we studied the variation of the strains and of the electrical potential, taking into account the changing of the parameters like the power voltage frequency, the power voltage amplitude, the distance between the support point and the edge of the discs system.
Quality Comparison of Analog and Digital X-Ray Equipment and Materials in a Dental Clinic
Authors: Kawamoto Luiz Teruo , Kawamoto Waltraudi Orchulhak , Formigoni Alexandre , Rodrigues Enio Fernandes , de Arruda Campos Ivan Pérsio , Rodrigues Silvia Cristina Martini
Published: August 2015

Many dental clinics are swapping analog x-ray equipment for digital systems to obtain medical images in the search for improvements such as reduced costs and better care of the images and fast response. However it is necessary to analyze if the digital images have quality requirements in order to provide the diagnosis in a similar or superior way to the analog films. The objective of this paper is to analyze the quality of the digitized x-ray diagnostic images in relation to the structures represented. The research was conducted in a dental clinic that was changing the analog x-ray equipment for one digital. The results by means of statistical analysis demonstrated that the digital system has better spatial resolution and better contrast. As a suggestion of future research an analysis by dentists to see if on the day of the clinic, these theoretical advantages are confirmed in better diagnostics.
The Rationalization of Production of Ring-Shaped Drop Forgings Using Computer Simulation of Closed-Die Forging Process
Authors: Kapustova Maria
Published: August 2015

The rationalization of ring-shaped drop forgings production may be considered from different points of view. Important aspects of evaluation and selection of optimal production alternative are material and energy savings and issue of forging tool life. This contribution describes advanced technology of closed die forging without flash, which represents an effective method of manufacture of ring-shaped drop forging from steel alloy type 16MnCr5. This proposed method offers a cheaper possibility of production of mentioned forging piece resulting from saving of batch material. At present drop forgings with this shape are produced by an uneffective method, i.e. die forging with flash, which brings a considerable material loss. Simulation software determined for simulation of bulk forming processes have an important position at development of new advanced technologies of drop forgings production. A simulation program MSC.SuperForge described in this contribution was used in order to verify correct plastic flow of material in closed die cavity.
A Review on Mechanical Properties of Geopolymer Composites for High Temperature Application
Authors: Aziz Ikmal Hakem , Al Bakri A.M. Mustafa , Heah Cheng Yong , Yun Ming Liew , Hussin Kamarudin , Azimi Emy Aizat
Published: August 2015

Geopolymer is cementitious binder that has enormous potential to become an alternative to ordinary Portland cement (OPC). Geopolymer composites have the potential to substantially curb the carbon dioxide (CO2) emissions. Kaolin, metakaolin, slag and fly ash have been used as the prime materials for forming geopolymers composites. Geopolymers have been studied for the past decade due to its unique properties such as low shrinkage, substantially chemical resistance, and higher fire resistance. The geopolymer offer an innovative for coating application at higher thermal application. Based on historical review, geopolymer materials exhibit resistance to corrosion, abrasion and heat. This paper summarizes some research finding about alkali-activated binders over the past decades along with outlines of the potential of geopolymer composites for high temperature application.
Structural Health Monitoring System, Development and Testing
Authors: Bindean Ioan Andrei , Fofiu Mihai , Partene Eva , Stoian Valeriu Augustin
Published: August 2015

The work presents a system intended for continuous monitoring of structural parameters for any type of structure to provide a better understanding of structural and material behavior. The system is in the final stages of development and its purpose is to gather data via a bus connected to several displacement, temperature, noise, gas detection and vibration sensors. The system is designed to be modular, meaning that two more systems can work as one. The data gathered is sent to a web server from where it can be accessed and interpreted. The main advantage of the system is the accessibility, which takes into account the financial factor, size, power consumption and resistance to unfavorable conditions. The implementation of this kind of system can result in prolonged life span of the monitored structure. The use is not designed solely for long term use, it can also aid as a data acquisition device in experimental testing programs such as experimental retrofitting strategies. In this paper certain functions of the system are used to test the out of plane behavior of a nonstructural masonry infill wall. The main focus is to test the accuracy of the RLPTs under low voltage conditions and also test the software time based scheduled recording function accuracy and detect the occurrence of bugs or data loss.
Laser Cutting of Coronary Stents: Progress and Development in Laser Based Stent Cutting Technology
Authors: Muhammad Noorhafiza , Al Bakri Abdullah Mohd Mustafa , Saleh Mohd Shuhidan , Li Lin
Published: August 2015

Laser cutting is one of the key fabrication technologies applied to coronary stent manufacture. This paper reviews the recent progress in laser-based stent manufacturing, including different type of lasers used, laser interaction with different stent materials, process characteristics and quality/productivity issues.
Experimental Study of Active Vibration Control of a Flexible Beam System Using Iterative Learning Algorithm
Authors: Saad Mohd Sazli , Jamaluddin Hishamuddin , Mat Darus Intan Zaurah , Abd Rahim Irfan
Published: August 2015

Experimental studies are conducted on active vibration control using self-tuning proportional integral derivative and self-tuning proportional iterative learning algorithm control schemes to suppress vibration on a flexible beam via real-time computer control. An experimental rig is developed to investigate controller performance when a change in the dynamic behavior of the flexible beam system occurs. The performance of the self-tuning control schemes is validated experimentally and compared with that of conventional control schemes through the use of an iterative learning algorithm. Experimental results clearly reveal the effectiveness and robustness of the self-tuning control schemes over conventional control schemes.
Stone Monuments Consolidation with Nanomaterials
Authors: Ion Rodica Mariana , Fierăscu Radu Claudiu , Fierăscu Irina , Bunghez Ioana Raluca , Ion Mihaela Lucia , Caruţiu-Turcanu Daniela , Teodorescu Sofia , Rădiţoiu Valentin
Published: August 2015

Historical monuments suffer different forms of degradation, due to some improper works on architecture structure, vibrations caused by blasting, traffic, the inadequate restoration, the phenomenon of freeze-thaw, air pollution, humidity and temperature variations, friable mortar, deposits adhering impurities (dust, smoke, tar), soluble efflorescence, poorly soluble or insoluble salts (nitrate, sulfate, chloride, carbonate), and the action of microorganisms. Nowadays, the nanomaterials represent an alternative in architecture conservation, mainly due to their improved mechanical properties, their compatibility as consolidating materials, and because they obey the principle of authenticity of historical monuments. In this paper, hydroxyapatite nanoparticles (HAp) are applied to the chalk samples prelevated from Basarabi monument. Some physico-chemical and mechanical properties have been evaluated and discussed for untreated chalk stone and for the treated one with HAp.
Fire Resistant Properties of Geopolymers: A Review
Authors: Heah Cheng Yong , Liew Yun Ming , Al Bakri Abdullah Mohd Mustafa , Kamarudin Hussin
Published: August 2015

This paper presents fire and thermal properties on geopolymer binders, composed of metakaolin, slag and fly ash as precursor. Geopolymers are inorganic polymeric materials that are believed being capable to resist heat, high temperature and fire. Based on the previous researches, geopolymers offer a feasible alternative to fire resistance applications and with further deep studies, it has great potential to be fabricated for engineering applications.
Epoxy Hardener Filled with Geopolymer Materials for Piping Application: Flexural Properties
Authors: Abu Hashim Mohammad Firdaus , Al Bakri Abdullah Mohd Mustafa , Ghazali Che Mohd Ruzaidi , Kamarudin Hussin , Mohd Tahir Muhammad Faheem , Binhussain Mohammed
Published: August 2015

In this study, the effect of geopolymer materials in epoxy hardener was studied under mechanical testing which is using flexural test. A series of epoxy filled with 10%-30% weight percentage geopolymer materials which are white clay, fly ash and silica sand was prepared. Flexural strength of the epoxy filled geopolymer materials is determined using Instron Universal Testing under flexural mode. It was found that the addition of these geopolymer materials into epoxy at the beginning with 10% weight percentage showing lower flexural strength than epoxy without geopolymer materials filled. However, flexural properties suddenly increased at 20% weight percentage of white clay and fly ash based geopolymer but tend to decrease at 30% weight percentage compared to silica sand based geopolymer which the strength is continue to decline with the increasing of weight percentage of silica sand. The results indicated that the blending of geopolymer materials in epoxy system can be obtained in this study.
Considerations Regarding Sandblasting Metal Surfaces Designed for Electric Arc Spraying
Authors: Georgescu Iuliana Silvia , Genes Cristinel , Costache Camelia , Baciu Elena Raluca , Baciu Constantin , Arghirescu Adriana
Published: August 2015

In order to ensure adherence of the arc sprayed layer, on the metal substrate, a few specific operations must be performed: initial cleaning, degreasing, roughening, final cleaning and degreasing. At the moment, there are standards which refer to the degree of preparation for processing metal surfaces by spraying. Performing metallic surface preparation operations require compliance with specific health and safety measures and environment protection.