Volume 11, Issue 1, January 2020

The Journey of a Decade to Advancing Materials

Ashutosh Tiwari

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-6
DOI: 10.5185/amlett.2020.011455

The International Association of Advanced Materials, IAAM, was founded as a non-profit organization on Wednesday, 20 January 2010, with the aim for promotion of advanced materials to global excellence. The organization works to create a highly interactive international network of researchers, students, professionals from academia and industries working in the interdisciplinary fields of advanced materials science, engineering, and technology.

Are the Electrospun Polymers Polymeric Fibers?

S. Fakirov

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-3
DOI: 10.5185/amlett.2020.011456

In this short communication, an attempt is undertaken to demonstrate that the widely used practice to call the electrospun polymers from their solutions and melts “polymer nanofibers” is hardly correct for the following reasons. The polymer fibers prepared by means of the common melt-spinning are characterized by perfect molecular orientation of the parallel aligned macromolecules leading to superior mechanical performance. The electrospun polymers are also flexible cylindrical formations but with macromolecules in isotropic, non-oriented state and distinguished by poor mechanical properties, frequently inferior than those of the same polymer in isotropic state. For this reason, it is suggested to call these materials “fiber-like nanomaterials” instead of “polymer nanofiber”. The real target of the communication is to challenge the electrospinning community to modify the manufacturing process in such a way that the final nanomaterial is characterized by perfect molecular orientation resulting in excellent, typical for polymer fibers mechanical properties, which will offer wide real applications of these nanofibers. 

Mechanical and Thermal Properties of Composite Material and Insulation for a Single Walled Tank for Cryogenic Liquids

Philipp W. Kutz; Frank Otremba;Jan Werner

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-6
DOI: 10.5185/amlett.2020.011457

This paper describes the testing methods used to determine the thermal properties of insulation materials and mechanical properties of materials used for the load-bearing structure for pressure tanks (up to 4 bar, relative) and cryogenic liquids (LNG, −166 °C to -157 °C at atmospheric pressure). Goal is to design a transportation tank that does not exceed 4 bars (relative) within 10 h, starting at atmospheric pressure. PUR-foam is a suitable material for the insulation. A 12,5 l small scale tank prototype reached 4 bar (relative) within 87 minutes, which is, regarding the influence of the size, a satisfying result. The mechanical properties change significantly at cryogenic temperatures. The bending modulus is similar at first, but decreases at a certain point by appr. 50 %. However, the maximum stress is much higher and could not be reached within this testing setup. 

Prediction of Long-Term Behavior for Dynamically Loaded TPU

Robert Eberlein; Lucian Pasieka

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-6
DOI: 10.5185/amlett.2020.011458

Thermoplastic polyurethanes (TPU) are often subject to highly dynamic loading conditions in engineering applications. Due to their robust mechanical properties, TPU materials form an excellent fit for dynamically loaded system components in many cases. However, for dynamically loaded TPU the long-term material behavior is of special interest, since TPU shows distinct creep, as generally observed in polymers. This article illustrates a rather simple but efficient and consistent method for predicting the long-term material behavior of a selected TPU grade under uniaxial dynamic loading conditions. The research arises from practical challenges of design engineers. These are often confronted with lifetime quantification issues of critical components, e.g. in a mechanical damping element under cyclic loading conditions, for which a permissible deformation may not be exceeded. In those cases the transient stress-strain behavior of the material is of special interest. As will be shown an important prerequisite for the derivation of a reliable material model is the acquisition of relevant creep data for the respective TPU material. In a second step, the creep data is extrapolated in time by employing a suitable method resulting in a time-dependent stress relaxation modulus function. Parallel Maxwell models expressed by Prony parameters yield the rheological properties of this function. Due to their derivation, these Prony parameters represent quasi-static material response. Nevertheless, by employing a novel dynamic-static loading analogy the Prony parameters form the basis for TPU lifetime prediction under uniaxial dynamic loading conditions. By comparing numerical FE results for a damper with experimental results from an endurance test, the proposed modeling concept demonstrates its validity. 

Investigation of Doped Titanium Dioxide in Anatase Phase. Study ab initio using Density Functional Theory

Paulo José Pereira de Oliveira; Fabielle Castelan Marques; Arlan da Silva Gonçalves; Greice Kelly dos Santos Brito; Enzo Victorio Andrade; Marcos Pedro Dalmaso Pinto

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-5
DOI: 10.5185/amlett.2020.011459

Global warming has generated great concern worldwide. One way to control this problem is to use clean renewable energy new sources. Among the energy sources, we can mention hydrogen gas, produced by water photocatalysis by mean of a semiconductor material. In this work, we report a study about band gap and absorption spectra by mean of the density functional theory of the anatase allotropic form of titanium dioxide doped with Ruthenium. The results indicated systematic decrease of the band gap and increase of the absorbance at the visible region with the increase of the amount of dopant.

Comparison between Single Al2O3 or HfO2 Single Dielectric Layers and their Nanolaminated Systems

Raffaella Lo Nigro; Emanuela Schilirò; Patrick Fiorenza; Fabrizio Roccaforte

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-5
DOI: 10.5185/amlett.2020.011460

Plasma Enhanced Atomic Layer Deposition (PEALD) technique has been used for the fabrication of nanolaminated Al2O3-HfO2 thin films as well as of single Al2O3 and HfO2 layers on silicon substrates. The three different layers, i.e. Al2O3, HO2 and the nanolaminated Al2O3-HfO2 thin films, which consists of very thin alternating layers of Al2O3 and HfO2, have been deposited at temperature as low as 250°C. Each of them possesses a total thickness of about 30 nm and has been tested as possible dielectric for microelectronics devices. In particular, the structural properties and their evolution upon annealing treatment at 800°C have been investigated. Moreover, the dielectrical properties of the nanolaminated system have been compared to the opposite single Al2O3 and HfO2 layers. The collected data pointed out to promising properties of the fabricated nanolaminated film. Copyright © VBRI Press.

Preparation of Stable and Optimized Antibody-gold Nanoparticle Conjugates for Point of Care Test Immunoassays

Hitesh P. Chauhan; Abhishek Soni; Dr. Vipul Kheraj; Dr. Bharatkumar Z. Dholakiya

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-5
DOI: 10.5185/amlett.2020.011461

Immunoassays are the most reliable andcost-effective for the diagnosis of various diseases also the common platform that helps us identify the unknown protein in a short period of time. The market is flooded with different types of diagnostic immunoassays but it is necessary to develop more cost-effective immunoassay with increased performance. The major cost factor in this regard is the quality and amount of biomolecules that are being utilized in the product. Optimization of biomolecules can aid us in developing cost-effective products without compromising its performance. This study aims to optimize the maximum amount of antibodies that can be conjugated on commonly used 40 nm gold nanoparticles that are indicators for the conclusion of test results. The excess usage of antibody may increase unnecessary product cost as it may get eliminated during the washing steps, while the lower amount of antibody usage may reduce the product’s performance in terms of sensitivity and stability. This study helps the manufacturer and researchers to find the optimum value of antibody molecules that can be conjugated on the surface of 40 nm gold nanoparticles. According to this study, ~3.4µg of antibody molecules is sufficient to saturate the surface of 40 nm gold nanoparticles of optical density 1.0. 

Resonance-Based Temperature Sensors using a Wafer Level Vacuum Packaged SOI MEMS Process

Gulsah Demirhan Aydin; Tayfun Akin

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-8
DOI: 10.5185/amlett.2020.011462

This paper reports the development of resonance-based temperature sensors using a wafer level vacuum packaged SOI MEMS process which is normally used to implement various MEMS sensors, including MEMS gyroscopes and accelerometers. Implementing MEMS temperature sensors in such a MEMS process together with sensitive MEMS sensors allows obtaining temperature data, which is very useful for the compensation of a number of parameters of these MEMS sensors for obtaining improved performance from these sensors. Four different types of temperature sensors are designed considering two types of actuation mechanisms (varying gap and varying overlap) and two different mass types (H-shaped single mass and tuning fork double mass), and their design and model analysis are verified using finite element modelling (FEM) simulations. All of the sensors are fabricated in the same die by using the advanced MEMS (aMEMS) process. The fabricated sensors are combined with necessary readout electronics for each structure in LT Spice environment, and their proper operations are verified in MATLAB Simulink. The temperature sensing technique is based on the frequency variations due to the thermal expansion coefficient mismatch between the glass substrate and the silicon that causes a mechanical strain on the resonator and to a smaller extent, by the temperature variation of Si Young modulus, which influences the resonance frequency. The performance of each sensor is measured using the real time data acquisition from the resonators where resonance frequency and resonator controller outputs are monitored for different temperatures. The best performance is obtained with the tuning fork double mass together with varying gap structures, where the temperature coefficient of frequency (TCF) values are measured as ‑128 ppm/K in the measurement range in the hot plate and as ‑114 ppm/K in the measurement range in the oven.

Integrated System Based on the Hall Sensors Incorporating Compensation of the Distortions

Miha Gradišek; Janez Trontelj

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-4
DOI: 10.5185/amlett.2020.011463

This paper addresses the realization of the integrated magnetic field measurement microsystem incorporating regulation electronics for compensation of its non-idealities and environmental influence. The core of the integrated, silicon based, microsystem represents the Hall element sensor which still promises the optimal approach regarding performance versus fabrication cost in a standard 0.35µm CMOS technology. Research is mainly focused on the rejecting the influence of the temperature dependant sensor characteristics with intention of the overall performance improvement. Proposed approach adjust the measured signal with accuracy of 455ppm/°C for all fabrication processes and temperature extending from -40°C up to 130°C and typically up to 32ppm/°C for same process.

The Efficacy of Cinnamomum Tamala as a Potential Antimicrobial Substance against the Multi-Drug Resistant Enterococcus Faecalis from Clinical Isolates

Muazzam Sheriff Maqbul; Aejaz A. Khan; Tasneem Mohammed; S.M. Shakeel Iqubal; Abdul Rahman Ikbal; Ibrahim Ahmed Shaikh; Uday Muddapur; Mohammed Shahid Hussain; S. K. Singh

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-4
DOI: 10.5185/amlett.2020.011464

The present study showcases the efficacy of Cinnamomum tamala (C. tamala) as a potential antimicrobial substance against the multi-drug resistant Enterococcus faecalis (E. faecalis) bacterium. The one of the most vulnerable bacteria to this spice was E. faecalis but due to lack of authentic evidences the treatment with this spice was diminished and used as a culinary spice till date to provide flavor without knowing its medicinal values which has given rise to the discovery of synthetic chemical antibiotics to treat these infections. This is an attempt to resurrect the ancient phyto-pharmaceutic techniques for combating the pathogenic bacteria as our time with the synthetic chemical antibiotic drug is draining out which gives rise to the multi-drug bacteria which becomes difficult to be treated. These types of natural resources is an alternate for the toxic synthetic chemicals with zero side effects. Enterococcus faecalis clinical isolate from the different samples showed the best susceptibility with the essential oil extract determined by the Kirby Bauer Disc Diffussion technique with satisfactory MIC and MBC results. The results obtained for the antibacterial properties of Cinnamomum tamala dried leaves essential oil extract recorded were excemplary from the performed standard antibiotic assay which determines that the efficacy of the natural essential oil proved to be an excellent alternative to treat infectious bacterial diseases.

The Effect of Complexing Reagent on Structural, Electrical and Optical Properties of CuS Thin Film

A.V. Mitkari; A.U. Ubale

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-5
DOI: 10.5185/amlett.2020.011465

Semiconducting CuS thin films were successfully prepared by Successive Ionic Layered Adsorption Reaction technique at room temperature with and without using complexing reagent viz.  hydrazine hydrate (H6N2O(N2H2),tri ethanol amine (C6H15NO3 ) and ammonia (NH3) . The structural studies revealed that; the crystallinity of the film can be tailored by using complexing agent. The dc electrical resistivity measured in the temperature range 370–473 K confirmed its semiconducting nature of CuS and it varies depending on complexing reagent. The optical absorption measurements were studied in the wavelength range 350–950 nm . The thermo-emf measurements confirmed that the films prepared are semiconducting in nature with p-type conductivity. 

Laser Cladding of Fluorapatite Nanopowders on Ti6Al4V

Amin Nakhi; Monireh Ganjali; Haji Shirinzadeh; Ali Sedaghat Ahangari Hossein Zadeh; Masoud Mozafari

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-5
DOI: 10.5185/amlett.2020.011466

In this study, at first fluorapatite nanopowder (nfAp) was initially synthesized by sol-gel method and then deposited on Titanium alloys (Ti-6Al-4V) using laser cladding technique. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) equipped with electron dispersive spectroscopy (EDX), were applied to study the crystallite and particle size, phase and chemical structure and microstructure the powder and coating sample. The results of XRD analysis and FTIR showed the presence of fluorapatite phases and ions replacement of F with OH in the structure of apatite. The MTT cell viability assays were used to study the biocompatibility of the coating samples. The average size of the crystallites estimated from XRD patterns using the Scherrer equation was 44 nm. The prepared nfAp coating deposited on Ti6Al4V showed well-behaved biocompatibility properties.

Preparation and Evaluation of Sulfonate Polyethylene Glycol Borate Ester as a Modifier of Functional Properties of Complex Petroleum Lithium Grease

Nagwa M.M. Hamada; Tarek M.M. Hamada; Nagy S. Sakr; Hassan E. Ali

Advanced Materials Letters, 2020, Volume 11, Issue 1, Pages 1-6
DOI: 10.5185/amlett.2020.011467

The goal of our study is the synthesis and evaluation of new additives to increase the dropping point and improving the extreme pressure (EP) properties of prepared Lithium 12-hydroxy stearate grease samples. High dropping point, extreme pressure properties (EP) and low oil separation are often the most important factors. The target additive, polyethylene glycol borate esters were synthesized via the stoichiometric reaction of poly ethylene glycol 400 and boric acid to give polyethylene glycol borate ester (PB) which reacted with the linear alkyl benzene sulfonate (1:1) in the presence of toluene as azeotrope to give the target sulfonate ester (SPB). The structure of the new synthesized polyethylene glycol borate esters (PB) and (SPB) were confirmed by using FT-IR. High performance liquid chromatography technique was used to confirm the purity and reactivity of the borate ester (PB) as a precursor for the synthesis of the target additive (SPB). The two new synthesized additives showed the ability to improve some properties of the prepared grease samples such as grease consistency ASTM D-217, dropping point ASTM D-2265 and oil separation ASTM D-6184. Four–Ball test ASTM D-2783 showed better capacities of (SPB) may due to the presence of the sulfonate group.