bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Polymer Additive on Gas Permeability Coefficient of Concrete
Authors: Chmielewska Bogumiła
Published: April 2013

Polymer-cement composites are valuable repair materials for concrete construction. Their mechanical and technological characteristics differ from those of materials containing only mineral components. One of the most important properties determining the sustainability of the composite is gas permeability coefficient. The influence of concrete composition on the value of gas permeability coefficient is discussed in the paper. Methods of the coefficient determination are characterized. The paper presents the research on the influence of polymer additive on the permeability coefficient of concrete as compared to the concrete without additive.
Application of PC and PMC in Industry and Industrial Environment
Authors: Fowler David W.
Published: April 2013

Abstract: Polymer concrete and polymer-modified concrete have been widely used around the world since the 1970s. Polymer concrete has been used for repair of portland cement concrete, for overlays and for precast components. Polymer-modified concrete has been used extensively for overlays for bridges and parking facilities and as a thin spray-on mortar for exterior surfaces.
Physical Properties of Polyester Polymer Concrete Composite Using RCSS Fine Aggregate
Authors: Hwang Eui Hwan , Kim Jin Man , Park Sun Gyu
Published: April 2013

For the recycling of rapid-cooled steel slag (RCSS), various specimens were prepared with the different replacement ratios of RCSS and the addition ratios of polymer binder. The physical properties of these specimens were then investigated by compressive strength test, flexural strength test, water absorption test, hot water resistance test, measurement of pore distribution and observation of micro-structures using scanning electron microscope(SEM). Results showed that compressive and flexural strength increased with the addition ratios of polymer binder and replacement ratios of RCSS, but those strengths decreased reversely when addition ratio of polymer binder and replacement ratio of RCSS were excessively high. By the hot water resistance test, the compressive strength and flexural strength decreased remarkably and total pore volume increased but bulk density decreased. SEM observation of structure before hot water resistance test revealed very compact infusion of structure but decomposition or thermal degradation appeared in polymer binder when observed after the hot water resistance test.
Effects of Redispersible EVA and E/VL/VC Powders on Properties of Decorative Mortar
Authors: Zhu Hui Mei , Wang Pei Ming , Zhang Guo Fang , Wang Ru
Published: April 2013

Redispersible polymer powders of Vinyl acetate / ethylene copolymer (EVA) and Ethylene/vinyl laurate/vinyl chloride copolymer (E/VL/VC) were applied to modify decorative mortar. Results showed that EVA and E/VL/VC both smoothed the surface of mortar, decreased the leachability of Ca2+, K+, Na+ ions and increased the leachability of SO42- in the surface leaching solution. However, with redispersible EVA and E/VL/VC being the same content, E/VL/VC-modified mortar hydrated for 1d showed lower bulk density, better surface hydrophobicity, higher alkalis leachability and more severe efflorescence. Moreover, EVA and E/VL/VC both had little influence on the components of efflorescence substances on the surface of mortar.
Influence of White Cement Content on the Performance of Decorative Mortar in the Presence of Microemulsion
Authors: Wang Ru , Wang Li , Wang Pei Ming , Xu Gang
Published: April 2013

The influence of white cement content on the compressive strength, flexural strength, tensile bond strength, water capillary absorption, anti-efflorescence and stain resistance of decorative mortar in the absence or presence of microemulsion were studied in this paper, meanwhile the effect of the microemulsion was analyzed. The results showed that the increasing white cement content increases the compressive and flexural strengths, reduces the water capillary absorption, and improves the stain resistance of the decorative mortar, but has adverse effect on the anti-efflorescence. While the tensile bond strength first increases and then decreases with the increase of the white cement content, and as the content of which is 7%, there appears a maximum value of tensile bond strength. The microemulsion improves the performance of the decorative mortar, particularly significantly enhancing the anti-efflorescence and stain resistance, except for the improvement of compressive and flexural strengths.
Measuring the Effectiveness of Hydrophobic Layers Using a Non-Destructive Method
Authors: Antons Udo , Weichold Oliver , Raupach Michael
Published: April 2013

The paper focuses on the relationship between the effective hydrophobic layer thickness and the durability of impregnated hydrophobic treatments using single-sided nuclear magnetic resonance measurements. Weathered and non-weathered specimens were compared to detect the influence of different exposures on the performance of hydrophobic layers. The results show that structural changes caused by carbonation of blast furnace cement based concrete have an effect on the hydrophobic layer thickness while the carbonation of Portland cement concrete has none.
Polymers for Concrete Modification – Interactions and Application Properties
Authors: Pakusch Joachim , Wang Sheng Xian , Iyer Sridhar
Published: April 2013

Concrete is globally the most widely used construction material featuring outstanding properties as e.g. high mechanical strength, global availability, low cost and high durability if properly made. However, concrete exhibits also numerous intrinsic drawbacks as e.g. low tensile strength, poor elasticity, in many cases poor adhesion to various substrates and the formation of cracks and thus reduced durability. Many if not all of these drawbacks can be compensated by the addition of environmentally friendly water-based polymer dispersions. This article focuses on the fundamental understanding of the interaction of polymers with the other components in concrete, and its impact on the properties of latex-modified concrete (LMC), such as rheology, mechanical properties, adhesion, abrasion resistance etc. As a practical example the application of LMC in North American bridge deck overlays is discussed. Special attention is thereby paid to concrete mix designs, performance enhancement and the durability of these materials in the field.
Film Formation of a Non-Ionic Ethylene-Vinyl Acetate Latex Dispersion in Cement Pore Solution
Authors: Pavlitschek Thomas , Jin Yu , Plank Johann
Published: April 2013

Environmental scanning electron microscopy (ESEM) and complementary methods were employed to study the time dependent film formation of a non-ionic latex dispersion in water @ pH 12.8 and cement pore solution. A commercial liquid ethylene-vinyl acetate latex dispersion stabilized with PVOH possessing a minimum film forming temperature (MFFT) of 3 °C and a Tg of 19 °C was employed in the study. Prior to ESEM imaging the latex dispersion was stored at room temperature and then transferred into the ESEM instrument for imaging. Subsequently, micrographs monitoring its film forming behaviour are obtained. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. In synthetic cement pore solution film formation occurs faster than in water and is complete within one day. This acceleration can be ascribed to the presence of PVOH on the surface of the latex particles. In water at neutral pH, PVOH forms a shell around the latex particle and hinders the interdiffusion of the macromolecules while in cement pore solution, PVOH precipitates due to high pH and high concentration of cations. This way the latex particles can coalesce faster into a polymer film.
Some Aspects about Adsorption of Polymer on Cement Grain
Authors: Zhong Shi Yun , Han Dong Dong , Li Jin Mei
Published: April 2013

Whether and how many polymer particles will be adsorbed on the cement grain in the polymer-modified cement composites (PCC) is still a question. In this paper the possibility and the test method of adsorption of polymer particles on the cement grain were reviewed. A theoretical analysis on the principle of adsorption was discussed. It was then summarized that polymer particles will be adsorbed by the cement mainly due to electrostatic attract and the entropy effect. The zeta potential measurement based on the electroacoustic principle is a useful tool to study the adsorption of polymer, in combination with sedimentation of the polymer latex-modified cement with high water/cement (W/C) ratio quantitative evaluation of the adsorption is possible.
Remodeling of Deteriorated Irrigation Aqueducts Using Precast Polymer Concrete Flume
Authors: Yeon Kyu Seok , Kawakami Makoto , Choi Yoon Sang , Hwang Jin Yong , Min Seung Ho , Yeon Jung Heum
Published: April 2013

This study is designed to review the causes and modes of deterioration in irrigation aqueducts constructed with reinforced concrete, and introduce existing rehabilitation and new remodeling methods. As a result, because of the typical nature of irrigation aqueducts that are exposed to severe natural environment, the causes and modes of deterioration were more complex and diverse than other concrete structures. Also, due to the thinner cross sectional thickness of the structure, conducting a rehabilitation work was turned out to be difficult. As an active method for settling this problem, this study developed a method to remove the entire flume, upper structure of aqueduct, and replace with a precast flume constructed with polymer concrete. A loading test was performed using full-scale specimens, and then the suggested remodeling method was implemented in the actual field structures. The investigation showed that the suggested remodeling method was appropriate to secure the sustainability.
Rehabilitation of Deteriorated Agricultural Waterways due to Polymer Cement Mortar
Authors: Kawakami Makoto , Yeon Kyu Seok , Seong Kim Yong , Hwang Jin Yong , Omata Fujio
Published: April 2013

Recently the deterioration and rehabilitation of waterways made of reinforced concrete as agricultural hydraulic structures are urgent issues. The main causes of deterioration of these waterways are peculiarly abrasion of concrete at the side wall and bottom slab due to the current containing fine sand particles, cavitation and water jet. The typical deterioration is exposure of aggregate, peeling off and corrosion of the surface, and cracks corresponding to the above causes. It is desirable for waterways after rehabilitation to ensure sufficient water supply capacity, high durability and strength of repaired materials. In this study, repair methods by use of epoxy resin primer and polymer cement mortar lining were investigated and effective countermeasure was proposed, and its trial construction was performed by the field test.
Strategies for Optimizing Mineral Corrosion Protection Mortars Used in a Sea-Water Environment
Authors: Weicken Hannes , Lohaus Ludger
Published: April 2013

Corrosion protection is absolutely essential for offshore steel constructions. As an alternative to the conventional corrosion protection systems, a thin layer of high-performance mortar (HPM) could be applied around the steel tower to protect it against the harsh marine conditions. In order to produce such a mineral system, a dense mortar with a high durability against chlorides, frost and abrasion should be designed. Furthermore, the application techniques of the corrosion protection systems require a mortar with high fluidity and high segregation resistance. This is achieved by using a high content of cement and through the addition of pozzolanic additives, such as fly ash and silica fume. However, the risk of autogenous shrinkage also rises with the increasing content of cement and silica fume, leading to microcracks in the mineral corrosion protection layer. The occurrence of cracks ultimately leads to an increased chloride and water ingress. The main objective of this research work is to improve the shrinkage behaviour of the HPM by using several admixtures. In addition to superabsorbent polymers (SAP), the effects of a shrinkage-reducing admixture (SRA) were investigated. Some conclusions were drawn about the effects of these admixtures based on the linear shrinkage strain, which was measured using a shrinkage cone. Furthermore, it is supposed that the SAPs have a positive influence on the mortar’s durability by interrupting the capillary pore structure in the hardened mortar. After hydration, the initial water-filled SAPs leave small well-distributed pores inside the hardened cement, thereby increasing the resistance against water and chloride ingress. Moreover, the remaining air voids provide additional room to accommodate the volume increment during frost periods. Both, the reductions of the autogenous shrinkage and the increased resistance against ingress of chlorides and water will be discussed in this paper.
Review on Application of Polymer Concrete in Singapore
Authors: Lu Jin Ping
Published: April 2013

Singapore is a small island country, but has won renown as uncorrupted government and high quality products. Independent testing and inspection played a very important role for this achievement[1]. The Housing and Development Board (HDB) is the sole public authority in Singapore and was set up as a statutory on 1 February 1960. Within 45 years, it built more than 700,000 flats housing approximately 86% of the population. Every year, around 40,000 new flats (about 400 blocks) are built up to meet the demands. In March 1992, HDB launched the 15-year main upgrading programme (MUP) to vying the finishes and facilities of old estates up to the standard of those in the new towns. The upgrading programme is a conscious effort by the government to provide a better living environment, strengthen existing community ties and enhance the value of our flats. The potential size of the upgrading program is approximately 370,000 units spread across 20 years, which works out to be 350 blocks per year. To ensure and maintain the high standards of the housing quality, Polymer concrete materials including polymer modified cement mortar, epoxy or PU floor screed and injection materials, and fibre-reinforced plastic (FRP) materials are extensively used in the new and upgrading projects. In this paper, the various applications of polymer concrete composites in Singapore are described and discussed. The various categories of polymer concrete composites are extensively used in Singapore’s public and private projects. To ensure and maintain the high standards of the building quality, independent testing and inspection plays a very important role. Through implementing a quality control program to ensure high standards in product quality and performance requirements, Housing & Development Board (HDB), Singapore's public housing authority and statutory board under the Ministry of National Development, screens and provides a comprehensive selection of quality products needed for HDB construction projects through HDB's Materials List [2] with a set of product evaluation requirement. The development of the requirements and specifications for various polymer concrete composite products are also described and discussed
Polycarboxylate-Lignosulfonate Copolymerized High Performance Water Reducing Agent: Preparation and Application
Authors: Sun Zhen Ping , Zhao Lei , Huang Xiong Rong , Yang Hui , Shui Liang Liang
Published: April 2013

A new polycarboxylate-lignosulfonate copolymerized high performance water reducing agent (PCL) was synthesized by polymerizing self-made methoxy polyethylene glycol methacrylate (MPEGMA), methacrylic acid (MAA), lignosulfonate (LS) and sodium methyl acryl sulfonate (SMAS) in aqueous solution. Influence of LS dosage used in synthesis on the performance of the product was investigated. The performance of the new polymer and compounds prepared by polycarboxylate based superplasticizer (PC) and LS were compared, which revealed that the former has better properties of plasticizing and strength improving. Engineering applications indicated that concrete incorporating the new superplasticizer has advantages on its cohesiveness and pumpability. Moreover, it’s not easy to bleed, segregate and stick to the ground.
The Adsorption of Superplasticizers on Cement Particles and its Relation with Dispersibility
Authors: Wang Zi Ming , Wang Ya Li , Lan Ming Zhang
Published: April 2013

The dispersing effect of superplasticizer is closely related to its adsorption behaviors on the surface of cement particles or the hydrates. But the relationship between the adsorption amount of superplasticizer and the fluidity of cement paste seems uncertain. To investigate the relationship between the adsorption amount and the fluidity of cement paste, three groups of cements with designed compositions and C3A mineral were prepared in lab. Four types of superplasticizer were used to measure the adsorption on various cements. The corresponding zeta potential of cement particles with superplasticzers and the fluidity of cement pastes were tested and analyzed. It was found that the adsorption amount of superplasticizer was inversely related to the fluidity of cement paste for a given superplasticizer. The zeta potential of cement particles in the paste was proportional to the adsorption amount of superplasticizer. The adsorption amount of different superplasticizers at the isoelectric point in C3A-H2O system was determined. The meaning of the “adsorption amount” was discussed. The author proposed that the superplasticizer in cement paste should include three parts, and the role of each part was discussed according to test results and analysis.
Discussion on the Performance and the Reduction of Shrinkage Induced by Polycarboxylate Superplasticizer
Authors: Wang Zi Ming , Lu Fang , Lu Zi Chen , Li Hui Qun , Liu Xiao
Published: April 2013

The shrinkage-reducing type polycarboxylate superplasticizer (SRPCA) has become a hot research issue both at home and abroad for its perfect water-reducing ability, outstanding shrinkage-reducing and slump retaining ability. The effect of ordinary polycarboxylate superplasticizer (PCA) and shrinkage-reducing PCA on the drying shrinkage of cement mortar was studied thoroughly in this paper. The result showed that the SRPCA can effectively reduce the drying shrinkage of cement mortar. Moreover, the shrinkage-reducing mechanism was discussed from the aspect of molecular structure to the solution surface tension and also mortar water retention. It indicated that the solution surface tension had certain impact on the PCA shrinking-reducing ability, meanwhile the perfect water-retaining ability conduce to the shrinking-reducing improvement. esides, the introduction of shrinking-reducing functional groups to the ordinary PCE molecular structure can reduce the polymer solution surface tension, control the air content in the concrete and decrease the drying shrinkage of cement-based materials.
Flexural Toughness of Concrete with High Performance Polymers
Authors: Chin Chee Seong , Xiao Robert Yong
Published: April 2013

Flexural toughness is a measure of energy absorption capacity and characterization of material’s ability to resist fracture under flexure loads. Concrete, when unreinforced, behaves generally well in compression but its flexural behaviour particularly the post-peak performance is rather weak and brittle. Conventional method has been to include steel fibres to enhance the flexural capacity but was discouraged by their impractically heavy cost and weight constraints. This paper presents the use of high performance polymeric fibres as a cost-effective and lightweight potential alternative which also fits well into the modern era of sustainable construction seeing that they leaves substantially lower carbon footprint compared to steel. Mechanically deformed high performance polymer (HPP) made of 100 percent virgin polypropylene was adopted and incorporated into concrete mixes and its composite performance was experimentally investigated and compared to plain concrete and those reinforced by steel fibres. An analytical method to predict the overall flexural toughness response has also been proposed and verified.
Effect of Cross Sectional Shape of Polypropylene Fibers on Flexural Toughness of Composites and Fiber-to-Cement Matrix Adhesion
Authors: Behdouj Zahra , Jamshidi Masoud , Latifi Masoud , Halvaei Mana
Published: April 2013

Cement based material are weak in flexure in comparison to compression. Fibers have been used for 100 years ago in an industrial process (i.e. Hatschek machine) to improve flexural and tensile strength of cement based materials. Many researches have been performed to define the best fiber condition such as fiber type, length, and diameter. A few investigations have been done on the effects of fiber cross section on fiber-cement bonding and flexural strength. In this research, polypropylene (PP) fibers which have diversity in cross section were selected and used as reinforcement in cementitious composites. Fibers characterized for cross sectional shape and average surface area. Flexural strength of the specimens at different fiber volume contents was evaluated. Also, the adhesion of the fibers (with different cross sections such as hollow, delta and circular) was measured using the pull-out test. Results showed that the cross section has an important effect on bonding of the fibers to cement matrix and flexural toughness of the specimens. It was observed that the hollow fiber that has the biggest lateral surface showed the highest pull-out load, and the delta fiber showed best flexural behavior.
Fracture Properties of Curauá Fibers Reinforced Polymer Mortars
Authors: Reis João Marciano
Published: April 2013

The interest for the use of vegetal fibers as polymer reinforcement has recently increased because of their unique environmental and technological advantages. The aim of this research is to evaluate the feasibility of using Curauá (Ananas erectifolius) fibers as natural reinforcement of polymer mortars with particular regards to fracture and toughening mechanisms. Various weight fractions of aggregate 1%, 2%, 5% and 10% were replaced by the same weight of curauá fibers. A significant reduction of the specific weight of the polymer mortars and an improvement of their post-peak flexural behavior followed by less brittle failure was observed.
Effects of Calcium Contents in Class C Fly Ash Geopolymer
Authors: Guo Xiao Lu , Shi Hui Sheng , Lin Mao Song , Dong Wen Jing
Published: April 2013

Geopolymers with calcium contents were prepared from class C fly ash, metakaolin, and Ca(OH)2. Geopolymer products and ordinary cement hydration products were divided with gradient acid dissolution test. The effects of calcium in class C fly ash geopolymer were investigated through the calcium concentration of acid solution. In an appropriate alkali situation, most of the calcium will be dissolved from class C fly ash. Part of the calcium will react with silicate and aluminum to form geopolymeric gels as the presence of gismondine (zeolite). Part of calcium was hydrated to form calcium silicate hydrate(C-S-H), and the rest of calcium may be adsorbed within the geopolymeric binding structure to balance charge anion. The class C fly ash geopolymer is a composite system with the coexistence of geopolymeric and C-S-H gels.
Effect of Introducing Recycled Polymer Aggregate on the Properties of C-PC Composites
Authors: Sokołowska Joanna Julia , Piotrowski Tomasz , Garbacz Andrzej , Kowalik Paweł
Published: April 2013

The subject of this paper is the evaluation of possibility of using the plastic waste fillers as the coarse aggregate of two Concrete-Polymer Composites (C-PC): polymer-cement concrete (PCC) and polymer concrete (PC). The applied fillers were crushed high density polypropylene (HDPP) wastes remaining after grinding plastic elements used in mountings and thermal insulation systems. The substitution of natural mineral coarse aggregate (river gravel) with plastic material was done on the various levels (0 ÷ 40% in case of PCC and 0 ÷ 100% in case of PC). For all composites the density, flexural strength and compressive strength were determined and compared with those for reference composites containing only the river gravel. The results enabled to indicate the levels of possible substitution of the natural aggregate, the non-renewable resource, with waste material, so that the properties of C-PC remain at the satisfactory level.
Permeability and Porosity on Lightweight Mortars Fabricated with Polyamide Powder Wastes
Authors: Gadea Jesús , Salas Miguel Angel , Gutiérrez-González Sara , Rodríguez A. , Horgnies Matthieu , Calderón Verónica
Published: April 2013

This paper presents the results obtained in the production of lightweight mortars where different amounts of sand were replaced by polyamide powder wastes. The characterization of the materials obtained was carried out in fresh and hardened state, considering especially the vapor permeability and micro and macroporosity properties. It has been found that the progressive increase of polymer influences the behavior of the mortar, increasing the water vapour permeability as well as the total porosity of the material, which carried on a decrease in the density of the composites fabricated. These results suggest the employment of polyamide powder residue as sand could be useful with the aim of manufacture recycled lightweight masonry mortar.
Manufacture of Masonry Mortars with Melamine Powder Waste and Melamine Paper from the Manufacture of Agglomerated Particle Boards
Authors: Rodríguez A. , Calderón V. , Gutierrez S. , Gadea J. , Garabito J. , Junco C.
Published: April 2013

Our presentation develops the study of cement mortars manufactured with melamine waste, either in the form of powder or cellulose paper, taken from the industrial production of particle boards, characterizing all of their properties and comparing them with traditional cement mortars. The objective is to determine in what way the addition of melamine powder and melamine paper will modify traditional mortar, once these materials have been subjected to a polymerization process under pressure and under increased temperature, in order to assess the possibility of using these new materials for applications in the construction industry. The behaviour of mortar in the fresh state is studied, determining the variations produced with the addition of melamine powder and melamine paper on the workability and the on-site use of these mortars. Likewise, their mechanical properties under flexion, compression, and adherence to a ceramic surface are studied and compared with those obtained from the reference mortar. Water absorption by capillary action and vapour permeability are also studied, in order to understand the interaction of the polymerized melamine in the capillary network of the mortar. Dosages were prepared for a reference mortar and a further two series of mortars with different quantities of melamine powder and melamine paper, together with cement, sand and water. In this first phase, the use of additives in the mixtures was not considered. The process of selecting the materials and the dosage criteria of the mixtures are subsequently described. The results of the study show that the use of powder melamine and paper cellulose melamine can be used to manufacture mortars with properties that are equivalent to traditional mortars, although further studies with greater precision will be needed on the contribution of the melamine polymerization process to the internal structural cohesion of the mortar.
Recent Research on Polymer-Modified Cement Mortar in China
Authors: Wang Ru , Shi Xiao Xin , Wang Pei Ming
Published: April 2013

Polymer has been widely used in construction in China during the past few years and has become a necessary component of some building materials. The development in concrete-polymer composites (CPC) is going with the economical achievement and practical needs, which focuses on polymer-modified cement mortar (PCM). Therefore, this paper introduces the trends and advances in research on PCM during the past few years in China, especially cement hydration in the presence of polymer, the properties and application of PCM, waste utilization as well as trends of concrete-polymer composites.
Recent Advance in Synthesis and Application of Inorganic Glyconanoparticles as Bio-Therapeutics and Diagnostics Agents
Authors: Aich Udayanath
Published: April 2013

Carbohydrates are attractive molecules for drug discovery because sugars are involved in many intricate human diseases including cancer and infectious diseases. Potential therapeutic and diagnostic benefits of sugar-based drugs, however, are offset by the poor pharmacologic properties of these molecules that include speedy serum clearance, poor cellular uptake, and the relatively high concentrations required for efficacy. To address these issues, carbohydrates are functionalized with nanocarrier as similar to peptides, proteins and DNA. Considering the vast relevance of Inorganic nanoparticles as promising candidates for electronic, optical, magnetic and biomedical applications, several metals linked glyconanoparticles (GNPs) are synthesized and applied for biomedical application. This article will elaborately discuss about the progress in the development of metallic GNPs for various biological applications as drug candidates and detection agents.
Gold Nanotubes from Organic Scaffolds for Biomedical Applications
Authors: Mazumder Mohammad A. Jafar
Published: April 2013

Nanoparticles are the cutting edge of the rapidly developing field of nanotechnology, which enables visualization and manipulation of matter down to the atomic level. Their unique size to volume ratio, shape and thermal stability make these materials superior, and rapidly usable in various bio-medical applications. This brief review summarize the recent advances in the field of applied nanomaterials with an emphasis in designing nanoscale devices with pre-defined structure, and their potential applications in the field of biology and medicine.
Thiolated Gd(III) Chelate Coated Gold Nanoparticles: Synthesis, Characterization, X-Ray CT and MRI Relaxivity Studies
Authors: Shaikh M. Nasiruzzaman
Published: April 2013

Gadolinium complex of 2-aminothiophenol conjugated DTPA (DTPA=diethylenetriamine N,N,N',N",N" pentacetic acid) bis (amide) has been synthesized and characterized by various analytical techniques such as elemental analysis (EA), NMR, FAB-MS, IR, UV etc. This thiolated GdL (where L is a conjugate of DTPA and 2-aminothiophenol) has been anchored on the gold nanoparticles surfaces through thiols functionalites. These gold nanoparticles (AuNPs) have been synthesized by the reduction of gold tetrachloride (HAuCl4) using sodium citrate as reducing agent. The surface functionalization has been performed by the replacement of citrate coat on the gold nanoparticle surface with thiolated Gd-chelate, Au@GdL. The Au@GdL has been analyzed by XRD, transmission electron microscope (HRTEM), UV, ICP-MS etc. The average size of nanoparticles is about 22 nm with a uniform spherical shape. A very high number of GdL has been loaded on nanoparticle surface reaching up to 7.9x103 of Gd (III)- chelates per nanoparticle and they demonstrate very high r1 relaxivity and the r1 relaxivity per [G is much higher than the Gd (III)-chelate alone. The bimodality has also been tested using in-vitro x-ray computed tomography (x-ray CT). These nanoparticles (GNPs) are very stable and homogeneously dispersed in aqueous solution.
Surface-Enhanced Raman Scattering: A Technique of Choice for Molecular Detection
Authors: Hossain Mohammad Kamal
Published: April 2013

Although surface-enhanced Raman scattering (SERS) has crossed its infancy long ago, it is yet to persuade different challenges to make it available in day-to-day applications. SERS is being criticized mainly due to the quality of the SERS analyses that uses substrates to get the giant enhancement for respective Raman signal of the target molecule. Hence, understanding the phenomena behind substrates, cost-effective development and optimization of such substrates for routine analytical purposes and utilization of modern modalities to get the insights out has become a very wide-spreading and interesting area of research. In this piece of work, several key terminologies related to SERS have been presented in brief. Since SERS is a localized surface plasmon resonance (LSPR) mediated signal-enhancing phenomena, it is indispensable to understand the correlation between LSPR excitations originated from substrate and SERS signal originated from molecules. A wide range of SERS-active substrates including scattered nanoaggregates, anisotropic assembly, two-dimensional nanostructure, multi-layered nanostructure of gold nanoparticles and colloidal approach have been used to interpret such correlation between LSPR excitations and SERS characteristics. Few exemplary applications of SERS have been also mentioned followed by typical simulative work how nanoobject behaves at different excitations and polarizations.
Inorganic Nanoparticles and Nanomaterials Based on Titanium (Ti): Applications in Medicine
Authors: Al Othman Zeid A. , Alam Mohammad Mezbaul , Naushad Muhammad , Inamuddin Inamuddin , Khan Mohd Farhan
Published: April 2013

Nanomedicine is a relatively new field of science and technology. By interacting with biomolecules, therefore at nanoscale, nanotechnology opens up a vast field of research and application. Current and potential applications of nanotechnology in medicine range from research involving diagnostic devices, drug delivery vehicles to enhanced gene therapy and tissue engineering procedures. Its advantage over conventional medicine lies on its size. Operating at nanoscale allows to exploit physical properties different from those observed at microscale such as the volume/surface ratio. This allows drugs of nanosize be used in lower concentration and has an earlier onset of therapeutic action. It also provides materials for controlled drug delivery by directing carriers to a specific location. Inorganic nanomedicine is likely to remain one of the most prolific fields of nanomedicine, which refers to the use of inorganic or hybrid (inorganic-inorganic or inorganic-organic) nanomaterials (INMs) and nanoparticles (INPs) to achieve innovative medical advances for body parts implantation, drug and gene discovery and delivery, discovery of biomarkers, and molecular diagnostics. Among the most promising INMs being developed are metal, silica, dendrimers, organic-inorganic hybrids, ceramics (e.g. ZrO2, TiO2, Al2O3, etc.) and bioinorganic hybrids. Metal NP contrast agents enhance magnetic resonance imaging and ultrasound results in biomedical applications of in vivo imaging. Hollow and porous INMs have been exploited for drug and gene delivery, diagnostic imaging, and photothermal therapy. Biomolecular inorganic nanohybrids and nanostructured biomaterials have been exploited for targeted imaging and therapy, drug and gene delivery, and regenerative medicine. Potential uses for fluorescent quantum dots (QDs) include cell labeling, biosensing, in vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. Biocompatible QD conjugates have been used successfully for sentinel lymph node mapping, tumor targeting, tumor angiogenesis imaging, and metastasis cell tracking. This article outlines present developments and future prospects for the use of Ti-based NPs and NMs in experimental in vivo and in vitro studies and in engineering nanodevices and biosensors for clinical and investigative use in diagnosis and therapy in diverse fields of medical sciences, such as oncology, infection control, orthopedics, dentistry, dermatology, genetics, cardiology, ophthalmology, etc. Toxicological considerations of these INPs and INMs are also discussed.
DSC-TGA Hydrogen Evaluation during Mechanical Milling of AlFe Intermetallic
Authors: García de León M. E. , Téllez-Vázquez O. , Patiño-Carachure C. , Rosas Trejo Gerardo Antonio
Published: April 2013

Fe40Al60 (at%) intermetallic alloy composition was obtained by conventional casting methods and subsequently subjected to high-energy mechanical milling under different conditions of humidity. All samples were characterized by X-ray diffraction patterns (XRD), transmission electron microcopy (TEM) and DSC-TGA thermogravimetric experiments. After the milling process, the amount of hydrogen generated was determined using thermogravimetric analysis and chemical reactions (stoichiometry). All techniques confirm the formation of bayerite phase which is attributed to the hydrogen embrittlement reaction between the intermetallic material and water to release hydrogen. It was observed that the hydrogen generation is increased as the ball milling time is increased. The quantity of hydrogen evaluated is similar to that obtained in previous reported experiments with pure aluminum and some of its alloys.
Crystallization and Properties of Glass-Ceramics of the K2O-BaO-B2O3-Al2O3-TiO2 System
Authors: González M.A. , Gorokhovsky Alexander , Escalante J.I. , Ponce P. , Escobedo M.A.
Published: April 2013

Crystallization behavior and properties of glass-ceramics with content (mol%) of: K2O = 3-25, BaO = 3-27, B2O3 = 8-26, Al2O3 = 13-18, and TiO2 = 31-47 were studied. The relation between the initial composition and the formation of the crystalline phases was analyzed. When increasing [Al2O3] and [BaO], was increased the temperature of crystallization; likewise, different barium potassium titanates appeared with [BaO] = 3-13 (Group 1), whereas, different barium titanates were obtained with [BaO] =13-30 (Group 2). The influence of chemical composition on the properties of density, mechanical strength, chemical durability and dielectric properties (dielectric constant and dielectric losses), was discussed. Glass-ceramics with high mechanical resistance in the range of 189-480 MPa and permittivity values between 4.03 and 25.31, and dielectric losses < 2 x 10-4 at 1MHz were produced.
Structural Evolution of FeAl3 Intermetallic during High-Energy Ball-Milling
Authors: López-Miranda J. Luis , Romero-Romero J.R. , Esparza Muñoz Rodrigo Alonso , Rosas G.
Published: April 2013

In this work, we reported the results obtained by the structural characterization of the FeAl3 intermetallic compound. This material was synthesized by conventional casting technique using Fe (99.97%) and Al (99.92%) elemental metals. Then, the as-cast alloy was subjected to high-energy ball-milling for different times (1, 2.5, 5, 7.5, 10 and 15 h). The characterization of the alloy was performed by X-ray diffraction patterns, scanning and transmission electron microscopy. The results show that FeAl3 intermetallic was produced as a single-phase after conventional casting. The milled experiments show that the FeAl3 (monoclinic) transforms to Fe2Al5 (orthorhombic) after 15h of milling. Therefore, this phase transformation is characterized by a change from low to high symmetry systems.
Synthesis and Thermoluminescent Properties of New ZnO Phosphors
Authors: Burruel-Ibarra S.E. , Cruz-Vázquez C. , Bernal R. , Martínez-Castelo J.R. , García Haro A.R. , Orante-Barrón V.R.
Published: April 2013

In this work, results on the thermoluminescence dosimetry properties of beta particle irradiated ZnO obtained by thermal annealing of chemically synthesized ZnS are reported. ZnS powder was sintered at 950 °C during 24 h in air, in order to obtain pellet-shaped ZnO samples. The thermoluminiescence (TL) intensity of ZnO previously exposed to beta radiation increased as the dose increased in the 0.025-6.4 kGy interval studied. Characteristic glow curves exhibited two emission maxima at ~ 94 and ~ 341 °C. The dosimetric peak located at ~ 341 °C shifted towards lower temperatures as the dose increased, which indicates that second-order kinetic processes are involved in the thermoluminiescence emission. The dose response of ZnO showed a linear behaviour in the 0.025 Gy-0.8 kGy dose interval, which makes this material suitable and promising for medical, industrial and also space dosimetry applications. The thermoluminescence total signal faded down 48 % 6 h after irradiation and showed an asymptotic behaviour for longer times, due mainly to the ~ 341 °C stable and dosimetric glow peak.
Spectroscopy Study of Silver Nanoparticles Produced by Chemical Reduction
Authors: Ruíz-Baltazar A. , Esparza Muñoz Rodrigo Alonso , Pérez R. , Rosas Trejo Gerardo Antonio
Published: April 2013

In this study, Ag nanoparticles were synthesized using two chemical reduction agents; ethylene glycol and sodium borohydride. Different particle size distributions were obtained and characterized by transmission electron microscopy. Ag nanoparticles concentrations of 1, 2 and 4 parts per million (gmL-1) were prepared and studied by ultraviolet-visible spectroscopy (UV-Vis) and atomic absorption spectrophotometry (AAS). In the UV-Vis results a characteristic band at 420 nm were observed. However, when the concentration of silver decreased, a change in band intensity was detected. Atomic absorption spectrophotometry measurements from different solutions of Ag nanoparticles showed a linear behavior similar to the silver standard solution in the concentration range 1 to 4 mgL-1. However, up 4 mgL-1 concentrations, the slope of the calibration curve is increases when the concentration of Ag nanoparticles is increased too.
Characterization of the Microstructural Degradation of Platinum Modified Aluminide Coating
Authors: González M.A. , Martínez D.I. , Saucedo C.T. , Guzmán I. , Díaz J.C.
Published: April 2013

This work presents the degradation mechanism of the platinum modified aluminide diffusion coating of the GTD 111 SC Ni-base superalloy turbine blades after 16000 h of exposition at different thermal cycles (critical heating temperatures reported ~1000°C and 1120°C). The initial coating condition and the evolution of degradation were characterized applying conventional microscopy and backscatter scanning electron microscopy. The initial microstructure condition consisted of a two phase coating (intermetallics PtAl2 dispersed in a matrix β-(Ni,Pt)Al). The major microstructure degradation was associated with: intermediate and interdiffusion zones growing, partial transformation of β-(Ni,Pt)Al to γ´-Ni3Al, and the dissolution of the intermetallic PtAl2 resulting in a more brittle single phase β-(Ni,Pt)Al coating. The degradation facilitates spallation and crack initiation, resulting in the loss of the coating and by consequence the blade failure.
Analysis of Weld Bead Parameters of Overlay Deposited on D2 Steel Components by Plasma Transferred Arc (PTA) Process
Authors: García-Vázquez F. , Aguirre A. , Arizmendi-Morquecho Ana , Hernández-García H.M. , Santiago-Bautista L. , Acevedo J. , Vargas-Arista B.
Published: April 2013

Plasma Transferred Arc (PTA) process is increasingly used in applications where enhancement of wear, corrosion and heat resistance of metals surface is required. The shape of weld bead geometry affected by the PTA welding process parameters is an indication of the quality of the weld. PTA is a versatile method of depositing high-quality metallurgically fused deposits on relatively low cost surfaces. The overlay deposited is an alloy that is hard and more corrosion resistant than counterparts laid down by Gas Tungsten Arc Welding (GTAW) or Oxy Fuel Welding (OFW) processes. Weld deposits are characterized by very low levels of inclusions, oxides, and discontinuities. This process produces smooth deposits that significantly reduce the amount of post weld machining required. Metal-Mechanic industry continuously requires recovering tool steel components subjected to severe wear. The steel known as D2 is considered to be a high carbon, high chromium cold work tool steel. In this research, weld beads were deposited on D2 steel by using PTA process with different parameters as welding current and travel speed using base nickel filler metal. In order to evaluate the metallurgical features on the weld beads/substrate interface a microstructural characterization was performed by using Scanning Electron Microscopy (SEM) and to evaluate the mechanical properties was conducted the wear test.
Structural, Textural and Thermal Characterization of Nano-Mg/Al Hydrotalcite before and after Cr (VI) Removal
Authors: Ramos Ramírez Esthela , Gutiérrez Ortega Norma Leticia , Contreras Soto Cesar Augusto , Rangel Porras Gustavo
Published: April 2013

In this work there was studied the structural, textural and effect that has treat thermal on the removal of Cr (VI) of nanoMg/Al hydrotalcite (NHT) synthesized by the sol-gel method with a ratio of Mg/Al=3. These present the characterization of the nanoMg/Al hydrotalcite before and after Cr (VI) removal, as well as the kinetic studies and of balance. In agreement with the results, when the NHT are thermal treated to 350 °C the hydrotalcite crystalline structure remains but the textural properties are improved and structural. The NHT synthesized by the sol-gel method present a good capacity of removal with values of 91 mg of Cr (VI) removed / g of NHT. The above mentioned capacity of removal gets improved after thermal treating the material, reaching values of removal of 124 mg of Cr (VI) removed / g of NHT. The NHT with the Cr (VI) absorbed show decrease of the crystalline structure, as well as a saturation of the pores that annuls the porosity due to the fact that the Cr (VI) lodges both at the pores and at the intersheets. The time that him takes the HLM to remove the Cr (VI) of the watery solution is alone of 2 minutes, with which it is possible to conclude that the NHT have an excellent aptitude to remove Cr (VI) of watery solutions in an interval of very short time.
Effect on the Microstructure and Mechanical Properties of the Electromagnetic Stirring during GMA Welding of 2205 DSS Plates
Authors: García Rentería Marco Arturo , López Morelos Víctor Hugo , García Hernández Rafael , Curiel López Francisco , Lemus-Ruíz José
Published: April 2013

Plates, 6.3 mm thick, of 2205 duplex stainless steel (DSS) were gas metal arc welded (GMAW) under the application of an axial magnetic field (0 to 15 mT) with an ER-2209 filler wire using a gas mixture of 98%Ar + 2%O2. Microstructural characterization of the welds revealed that electromagnetic stirring (EMS) increases the content of austenite in both weld center and high temperature heat affected zone (HTHAZ). It induced a grain refining effect during freezing of the ferritic matrix which in turn enabled more sites for nucleation of austenite. This mechanism of solidification was reflected in an increase in the mechanical strength of the welds. Besides, the extent of the HTHAZ was reduced and its microhardness increased when applying the external magnetic field. It is believed that the vibration induced in this region favored the regeneration of austenite in the ferritized HTHAZ enhancing the balance of phases.
Characterization of Pt-Pd Bimetallic Nanoparticles by Cs-Corrected STEM
Authors: Téllez-Vázquez O. , Esparza Muñoz Rodrigo Alonso , Rodríguez-Ortiz G. , García-Ruiz Amado F. , Pérez R. , José-Yacamán Miguel
Published: April 2013

Pt-Pd bimetallic nanoparticles were characterized using aberration (Cs) corrected scanning transmission electron microscopy (STEM) along with molecular dynamics simulations. The nanoparticles were synthesized through a microwave-assisted process. This technique has been applied to synthesize metallic nanoparticles at relatively short times, allowing a good control of size distribution. The structure of the bimetallic nanoparticles is fcc-like with an average size of 5 nm. To understand the properties of the bimetallic nanoparticles, it is necessary to know the positions of all the atoms in the nanostructure. We have used a recent quantitative method to analyze HAADF STEM images which allowed us to measure the total intensity of the scattered electrons for each atomic column. Beside with the characterization of the nanoparticles, we have performed classical molecular dynamics simulation for the structural and dynamical analysis of the cuboctahedral Pt-Pd bimetallic nanoparticles.