Search results for: yttria stabilized zirconia

Authors: E. A. Asabina, V. I. Pet'kov, P. A. Mayorov, A. V. Markin, N. N. Smirnova, A. M. Kovalskii, A. A. Usenko

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The purpose of this work was to synthesize and investigate phase formation, structure and thermophysical properties of the phosphates M_0.5+xM'_xZr_2–x(PO₄)₃ (M – Cd, Sr, Pb; M' – Mg, Co, Mn). The compounds were synthesized by sol-gel method. The results showed formation of limited solid solutions of NZP/NASICON type. The crystal structures of triple phosphates of the compositions MMg_0.5Zr_1.5(PO₄)₃ were refined by the Rietveld method using XRD data. Heat capacity (8–660 K) of the phosphates Pb_0.5+xMg_xZr_2-x(PO₄)₃ (x = 0, 0.5) was measured, and reversible polymorphic transitions were found at temperatures, close to the room temperature. The results of Rietveld structure refinement showed the polymorphism caused by disordering of lead cations in the cavities of NZP/NASICON structure. Thermal expansion (298−1073 K) of the phosphates MMg_0.5Zr_1.5(PO₄)₃ was studied by XRD method, and the compounds were found to belong to middle and low-expanding materials. Thermal diffusivity (298–573 K) of the ceramic samples of phosphates slightly decreased with temperature increasing. As was demonstrated, the studied phosphates are characterized by the better thermophysical characteristics than widespread fire-resistant materials, such as zirconia and etc.

Keywords: NASICON, NZP, phosphate, structure, synthesis, thermophysical properties

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Authors: Júlio Cesar Lopes de Oliveira, Carlos Henrique Gonçalves Treviso

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The shortage of the automotive market in relation to options for sources of high power car audio systems, led to development of this work. Thus, we developed a source with stabilized voltage with 4320 W effective power. Designed to the voltage of 14.4 V and a choice of two currents: 30 A load option in battery banks and 300 A at full load. This source can also be considered as a source of general use dedicated commercial with a simple control circuit in analog form based on discrete components. The assembly of power circuit uses a methodology for higher power than the initially stipulated.

Keywords: DC-DC power converters, converters, power conversion, pulse width modulation converters

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Authors: P. W. Tsai, J. W. Chen, C. W. Chen, C. Y. Chen

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In recent years, many researchers are involved in the field of fuzzy theory. However, there are still a lot of issues to be resolved. Especially on topics related to controller design such as the field of robot, artificial intelligence, and nonlinear systems etc. Besides fuzzy theory, algorithms in swarm intelligence are also a popular field for the researchers. In this paper, a concept of utilizing one of the swarm intelligence method, which is called Bacterial-GA Foraging, to find the stabilized common P matrix for the fuzzy controller system is proposed. An example is given in in the paper, as well.

Keywords: half-circle fuzzy numbers, predictions, swarm intelligence, Lyapunov method

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Authors: Mokhtar Nikgoo

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Road definition and road construction: in engineering literature, a road is defined as a means of communication between two different places by air, land, and sea. In this way, all sea, land, and air routes are considered as roads. Road construction is an operation to create a road on the ground between 2 points with a specified width, which includes works such as subgrade, paving, placing tables, and traffic signs on the road. In this article, the stages of road construction are explained from the beginning to the end. Road construction is generally done in the construction of rural, urban, and inter-city roads, and according to the special conditions of this area, the precision of engineers in its design and calculations is very important. For example, if the design of a road does not pay enough attention to the way the road curves, there will undoubtedly be countless accidents. Also, adjusting the road surface and its durability and uniformity are among the things that engineers solve according to the upcoming obstacles.

Keywords: road construction, surveying, freeway, pavement, excavator

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Authors: Rabah Younes

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The reduction of available land resources and the increased cout associated with the use of high quality materials have led to the need for local soils to be used in geotechnical construction, however; poor engineering properties of these soils pose difficulties for constructions project and need to be stabilized to improve their properties in other works unsuitable soils with low bearing capacity , high plasticity coupled with high instability are frequently encountered hence, there is a need to improve the physical and mechanical characteristics of these soils to make theme more suitable for construction this can be done by using different mechanical and chemical methods clayey soil stabilization has been practiced for sometime but mixing additives, such us cement, lime and fly ash to the soil to increase its strength.

Keywords: clay, soil stabilization, naturaln pozzolana, atterberg limits, compaction, compressive strength shear strength, curing

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Authors: Daseul Lee, Jeong Jun Lee, Ok-Sang Jung

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Self-assembly of a series of ZnX2 (X- = Cl-, Br-, and I-) with 2,3-bis(4’-nicotinamidephenoxy)naphthalene (L) as a new bidentate pyridyl-donor ligand yields systematic metallacyclodimeric unit, [ZnX2L]2. The supramolecule constitutes a characteristically stacked forming both 1D suprachannels and cages. Weak C-H⋯π and inter-digitated π⋯π interactions are main driving forces in the formation of both suprachannels and cages. The slightly different features between the suprachannel and cage have been investigated by 1H NMR and TG analysis, which solvent quantitatively exchange within only suprachannels. Photo-unstable CH2I2 molecules are stabilized via capturing within suprachannels, which is monitored by UV-Vis spectroscopy. Furthermore, the photoluminescence intensity, from the chromophore naphthyl moiety of [ZnCl2L]2, gradually decreases with the addition of CH2I2. And washing off the CH2I2 by dichloromethane returned the PL intensity back to its approximately original signal.

Keywords: metallacyclodimer, suprachannel, π⋯π interaction, molecular recognition

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Authors: Mohamed Abdoul-Hakim, A. Zeroual, H. Garmes

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In this work, we theoretically evaluated the reactivity of four 4-methyl-3-oxo-1,2-pyrazolidinium ylides with 2-Chlorobenzimidazole in MeOH in basic medium using DFT at the B3LYP/6-311+G(d,p) level. The analysis of the results shows that apart from its ability to retain its electrons, the deprotonated 2-Chlorobenzimidazole has a higher nucleophilic character. The reaction requires energy input to initiate the nucleophilic attack of the 2-Chlorobenzimidazole anion, and the inclusion of the solvent effect facilitates the formation of two regioisomers via an intramolecular vinyl nucleophilic substitution (SNVi). The transition states of this latter step are stabilized by charge transfer interactions σ(N-C) →σ*(C-Cl) for the more favorable regioisomer and n(N)→σ*(C-Cl) for the other regioisomer.

Keywords: benzonitrile N-oxide, DFT, intramolecular vinyl nucleophilic substitution (SNVi), 4-methyl-3-OXO-1, 2-pyrazolidinium ylides

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Authors: A. Evcin, N. Çiçek Bezir, R. Duman, N. Duman

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Nowadays, a great concern is placed on the harmfulness of ultraviolet radiation (UVR) which attacks human bodies. Nanocarbon materials, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs) and graphene, have been considered promising alternatives to shielding materials because of their excellent electrical conductivities, very high surface areas and low densities. In the present work, carbon nanofibers have been synthesized from solutions of Polyacrylonitrile (PAN)/ N,N-dimethylformamide (DMF) by electrospinning method. The carbon nanofibers have been stabilized by oxidation at 250 °C for 2 h in air and carbonized at 750 °C for 1 h in H2/N2. We present the fabrication and characterization of transparent and ultraviolet (UV) shielding CNF/polymer composites. The content of CNF filler has been varied from 0.2% to 0.6 % by weight. UV Spectroscopy has been performed to study the effect of composition on the transmittance of polymer composites.

Keywords: electrospinning, carbon nanofiber, characterization, composites, nanofiber, ultraviolet radiation

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Authors: Mohammad Saberian, Mohammad Ali Rahgozar, Reza Porhoseini

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Peat soil is formed naturally through the accumulation of organic matter under water and it consists of more than 75% organic substances. Peat is considered to be in the category of problematic soil, which is not suitable for construction, due to its high compressibility, high moisture content, low shear strength, and low bearing capacity. Since this kind of soil is generally found in many countries and different regions, finding desirable techniques for stabilization of peat is absolutely essential. The purpose of this paper is to review the various techniques applied for stabilizing peat soil and discuss outcomes of its improved mechanical parameters and strength properties. Recognizing characterization of stabilized peat is one of the most significant factors for architectural structures; as a consequence, various strategies for stabilization of this susceptible soil have been examined based on the depth of peat deposit.

Keywords: peat soil, stabilization, depth, strength, unconfined compressive strength (USC)

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Authors: Romel N. Georgees, Rayya A Hassan, Robert P. Evans, Piratheepan Jegatheesan

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Among other traditional and non-traditional additives, polymers have shown an efficient performance in the field and improved sustainability. Polyacrylamide (PAM) is one such additive that has demonstrated many advantages including a reduction in permeability, an increase in durability and the provision of strength characteristics. However, information about its effect on the improved geotechnical characteristics is very limited to the field performance monitoring. Therefore, a laboratory investigation was carried out to examine the basic and engineering behaviors of three types of soils treated with a PAM additive. The results showed an increase in dry density and unconfined compressive strength for all the soils. The results further demonstrated an increase in unsoaked CBR and a reduction in permeability for all stabilized samples.

Keywords: CBR, hydraulic conductivity, PAM, unconfined compressive strength

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Authors: Musa Alhassan, Alhaji Mohammed Mustapha

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Review of studies carried out on the use of bagasse ash in the improvement of deficient soils in Nigeria, with emphasis on lateritic and black cotton soils is presented. Although, the bagasse ash is mostly used as additive to the conventional soil stabilizer (cement and lime), the studies generally showed improvement of geotechnical properties of the soils either modified or stabilized with the ash. This showed the potentials of using this agricultural waste (bagasse ash) in the improvement of geotechnical properties of deficient soils. Thus suggesting that using this material at large scale level, in geotechnical engineering practice could help in the provision of stable and durable structures, reduce cost of soil improvement and also reduces environmental nuisance caused by the unused waste in Nigeria

Keywords: bagasse ash, black cotton soil, deficient soil, laterite, soil improvement

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Authors: J. E. Mendes, L. Abrunhosa, J. A. Teixeira, E. R. de Camargo, C. P. de Souza, J. D. C. Pessoa

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Among the many promising nanomaterials with antifungal properties, metal nanoparticles (silver nanoparticles) stand out due to their high chemical activity. Therefore, the aim of this study was to evaluate the effect of silver nanoparticles (AgNPs) against Phomopsis sp. AgNPs were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. The synthesized AgNPs have further been characterized by UV/Visible spectroscopy, Biophysical techniques like Dynamic light scattering (DLS) and Scanning Electron Microscopy (SEM). The average diameter of the prepared silver colloidal nanoparticles was about 52 nm. Absolute inhibitions (100%) were observed on treated with a 270 and 540 µg ml-1 concentration of AgNPs. The results from the study of the AgNPs antifungal effect are significant and suggest that the synthesized silver nanoparticles may have an advantage compared with conventional fungicides.

Keywords: antifungal activity, Phomopsis sp., seeds, silver nanoparticles, soybean

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Authors: S. Kazadi, A. An, B. Shen

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We investigate the fitness of a male and female permanent magnetic levitation support for use as an axle on a rotor for a levitating motor. The support enables passive thrust and axial support for the axle as a result of the unique arrangement of permanent magnets. As the axial and thrust bearing aspects are derived from magnetic repulsion, it is not immediately clear that the repulsion is stiff enough to enable even low power motors. This paper describes the design and performance of two low power motors based on the magnetic levitation support. We find that our low power motors, with rotational speeds of 618 and 833 rpms, exhibit performance free from excess vibrations that might hinder performance. This means that the actuation of the motors is adequately stabilized by the axle and results in motors capable of being utilized despite the levitation support.

Keywords: levitating motor, magnetic levitation support, fitness, axle

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Authors: Ibrahim Isa Ali (Pantami), Abdu Jaafaru Bambale, Abimbola Alale, Danjuma Ibrahim Ndihgihdah, Muhammad Alkali, Adamu Idris Umar, Samson Olufunmilayo Abodunrin, Muhammad Dokko Zubairu, Moshood Kareem

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This paper discusses the consideration and trade-offs used for the implementation of robust systems for orbit stability; Telemetry, Command and Ranging (TC& R) for Nigcomsat-1R and applicability for planned NigComSat-2 satellites. NigComSat-1R satellite was built by China Academy of Space Technology (CAST). The Satellite designed with quad-band payload (L, C, Ku, and Ka) was launched on the 20th of December 2011. The functionality of all satellite is driven by robust systems including Attitude & Orbit Control System (AOCS) and TC&R. The planned Nigcomsat-2 is a high throughput Satellite expected to function with better AOCS and TC&R.

Keywords: AOCS, CAST, Nigcomsat-1R, TC&R

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Authors: Majid Bagherinia

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Lime and cement are frequently used as binders in the Deep Mixing Method (DMM) to improve soft clay soils. The most significant disadvantages of these materials are carbon dioxide emissions and the consumption of natural resources. In this study, three different biopolymers, guar gum, locust bean gum, and sodium alginate, were investigated for the improvement of soft clay using DMM. In the experimental study, the effects of the additive ratio and curing time on the Unconfined Compressive Strength (UCS) of stabilized specimens were investigated. According to the results, the UCS values of the specimens increased as the additive ratio and curing time increased. The most effective additive was sodium alginate, and the highest strength was obtained after 28 days.

Keywords: deep mixing method, soft clays, ground improvement, biopolymers, unconfined compressive strength

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Authors: E. Fereydouni, Laleh Maleknia , M. E. Olya

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The present research, nylon fabric dyed by pressure method with nano-Si, nano-Ti particles and SiO2-TiO2 nancomposite. The influence of the amount of Si, Ti and SiO2-TiO2 on the performance of nylon fabric was investigated by the use of Fourier transform infrared spectrophotometer (FTIR), horizontal flammability apparatus (HFA), scanning electron microscope (SEM), electron dispersive X-ray spectroscope (EDX), water contact angle tester (WCA) and CIE LAB colorimetric system. The possible interactions between particles and nylon fiber were elucidated by the FTIR spectroscopy. Results indicated that the stabilized nanoparticles and nanocomposite enhances flame retardancy of nylon fabrics. Also, the prominet features of nanoparticles and nanocomposite treatment can note increase of adsorption and fixation of dye.

Keywords: nano-Si, nano- Ti, SiO2-TiO2 nancomposite, nylon fabric, flame retardant nylon

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Authors: M. Vezir Kahraman, Emre Basturk

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Energy storage technology offers new ways to meet the demand to obtain efficient and reliable energy storage materials. Thermal energy storage systems provide the potential to acquire energy savings, which in return decrease the environmental impact related to energy usage. For this purpose, phase change materials (PCMs) that work as 'latent heat storage units' which can store or release large amounts of energy are preferred. Phase change materials (PCMs) are being utilized to absorb, collect and discharge thermal energy during the cycle of melting and freezing, converting from one phase to another. Phase Change Materials (PCMs) can generally be arranged into three classes: organic materials, salt hydrates and eutectics. Many kinds of organic and inorganic PCMs and their blends have been examined as latent heat storage materials. PCMs have found different application areas such as solar energy storage and transfer, HVAC (Heating, Ventilating and Air Conditioning) systems, thermal comfort in vehicles, passive cooling, temperature controlled distributions, industrial waste heat recovery, under floor heating systems and modified fabrics in textiles. Ultraviolet (UV)-curing technology has many advantages, which made it applicable in many different fields. Low energy consumption, high speed, room-temperature operation, low processing costs, high chemical stability, and being environmental friendly are some of its main benefits. UV-curing technique has many applications. One of the many advantages of UV-cured PCMs is that they prevent the interior PCMs from leaking. Shape-stabilized PCM is prepared by blending the PCM with a supporting material, usually polymers. In our study, this problem is minimized by coating the fatty alcohols with a photo-cross-linked thiol-ene based polymeric system. Leakage is minimized because photo-cross-linked polymer acts a matrix. The aim of this study is to introduce a novel thiol-ene based shape-stabilized PCM. Photo-crosslinked thiol-ene based polymers containing fatty alcohols were prepared and characterized for the purpose of phase change materials (PCMs). Different types of fatty alcohols were used in order to investigate their properties as shape-stable PCMs. The structure of the PCMs was confirmed by ATR-FTIR techniques. The phase transition behaviors, thermal stability of the prepared photo-crosslinked PCMs were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). This work was supported by Marmara University, Commission of Scientific Research Project.

Keywords: differential scanning calorimetry (DSC), Polymeric phase change material, thermal energy storage, UV-curing

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Authors: Mohammad R. Bhuyan, Mohammad J. Khattak

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Deterioration of flexible pavements due to crack reflection from its soil-cement base layer is a major concern around the globe. The service life of flexible pavement diminishes significantly because of the reflective cracks. Highway agencies are struggling for decades to prevent or mitigate these cracks in order to increase pavement service lives. The root cause of reflective cracks is the shrinkage crack which occurs in the soil-cement bases during the cement hydration process. The primary factor that causes the shrinkage is the cement content of the soil-cement mixture. With the increase of cement content, the soil-cement base gains strength and durability, which is necessary to withstand the traffic loads. But at the same time, higher cement content creates more shrinkage resulting in more reflective cracks in pavements. Historically, various states of USA have used the soil-cement bases for constructing flexile pavements. State of Louisiana (USA) had been using 8 to 10 percent of cement content to manufacture the soil-cement bases. Such traditional soil-cement bases yield 2.0 MPa (300 psi) 7-day compressive strength and are termed as cement stabilized design (CSD). As these CSD bases generate significant reflective cracks, another design of soil-cement base has been utilized by adding 4 to 6 percent of cement content called cement treated design (CTD), which yields 1.0 MPa (150 psi) 7-day compressive strength. The reduction of cement content in the CTD base is expected to minimize shrinkage cracks thus increasing pavement service lives. Hence, this research study evaluates the long-term field performance of CTD bases with respect to CSD bases used in flexible pavements. Pavement Management System of the state of Louisiana was utilized to select flexible pavement projects with CSD and CTD bases that had good historical record and time-series distress performance data. It should be noted that the state collects roughness and distress data for 1/10th mile section every 2-year period. In total, 120 CSD and CTD projects were analyzed in this research, where more than 145 miles (CTD) and 175 miles (CSD) of roadways data were accepted for performance evaluation and benefit-cost analyses. Here, the service life extension and area based on distress performance were considered as benefits. It was found that CTD bases increased 1 to 5 years of pavement service lives based on transverse cracking as compared to CSD bases. On the other hand, the service lives based on longitudinal and alligator cracking, rutting and roughness index remain the same. Hence, CTD bases provide some service life extension (2.6 years, on average) to the controlling distress; transverse cracking, but it was inexpensive due to its lesser cement content. Consequently, CTD bases become 20% more cost-effective than the traditional CSD bases, when both bases were compared by net benefit-cost ratio obtained from all distress types.

Keywords: cement treated base, cement stabilized base, reflective cracking , service life, flexible pavement

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Authors: Timur Mukhametkaliyev

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The earthen material possesses low compression strength, and it is highly sensitive to the water content. Different binders can be added (Portland cement or lime) to improve the durability and the mechanical characteristics of earthen material, but the production of these binders has high embodied energy and results in an increase in world CO₂ emission. Geopolymers are binders which can be synthesized at low temperature in alkaline solutions from raw materials consisting of amorphous aluminosilicates. Geopolymers are an attractive substitution of Portland cement and can be used as an excellent stabilization for earthen material. In this study, earthen material stabilized with geopolymer binder for use in construction 3D printing was developed. Construction 3D printing offers freedom of design, waste minimisation, customisation, reduced labour, and automation. For successful 3D printing, the properties of used material are the most important aspects because they require adaptability for extrusion and controlled time of hardening for the binder.

Keywords: 3D printing, building construction, geopolymer, architecture

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Authors: Panumard Kaewmora, Thirasak Rirksomboon, Vissanu Meeyoo

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Due to the globally growing demands of petroleum fuel and fossil fuels, the scarcity or even depletion of fossil fuel sources could be inevitable. Alternatively, the utilization of renewable sources, such as biomass, has become attractive to the community. Biomass can be converted into bio-oil by fast pyrolysis. In water phase of bio-oil, acetic acid which is one of its main components can be converted to hydrogen with high selectivity over effective catalysts in steam reforming process. Steam reforming of acetic acid as model compound has been intensively investigated for hydrogen production using various metal oxide supported nickel catalysts and yet they seem to be rapidly deactivated depending on the support utilized. A catalyst support such as Ce1-xZrxO2 mixed oxide was proposed for alleviating this problem with the anticipation of enhancing hydrogen yield. However, catalyst preparation methods play a significant role in catalytic activity and performance of the catalysts. In this work, Ce0.75Zr0.25O2 mixed oxide solid solution support was prepared by urea hydrolysis using microwave as heat source. After that nickel metal was incorporated at 15 wt% by incipient wetness impregnation method. The catalysts were characterized by several techniques including BET, XRD, H2-TPR, XRF, SEM, and TEM as well as tested for the steam reforming of acetic acid at various operating conditions. Preliminary results showed that a hydrogen yield of ca. 32% with a relatively high acetic conversion was attained at 650°C.

Keywords: acetic acid, steam reforming, microwave, nickel, ceria, zirconia

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Authors: Balamurugan L.

Abstract:

Artificial intelligence (AI) and its applications in Intellectual Property Rights (IPR) has been significantly growing in recent years. In last couple of years, AI tools for Patent Research and Patent Analytics have been well-stabilized in terms of accuracy of references and representation of identified patent insights. However, AI tools for Patent Prosecution and Patent Litigation are still in the nascent stage and there may be a significant potential if such market is explored further. Our research is primarily focused on identifying potential whitespaces and schematic algorithms to automate the Patent Prosecution and Patent Litigation Process of the Intellectual Property. The schematic algorithms may assist leading AI tool developers, to explore such opportunities in the field of Intellectual Property. Our research is also focused on identification of pitfalls of the AI. For example, Information Security and its impact in IPR, and Potential remediations to sustain the IPR in the digital environment.

Keywords: artificial intelligence, patent analytics, patent drafting, patent litigation, patent prosecution, patent research

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Authors: W. Rashmi, M. Khalid, O. Seiksan, R. Saidur, A. F. Ismail

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Nanofluids have received much more attention since its discovery. They are believed to be promising coolants in heat transfer applications due to their enhanced thermal conductivity and heat transfer characteristics. In this study, the enhancement in heat transfer of CNT-nanofluids under turbulent flow conditions is investigated experimentally. Carbon nanotube (CNTs) concentration was varied between 0.051-0.085 wt%. The nanofluid suspension was stabilized by gum arabic (GA) through a process of homogenisation and sonication. The flow rates of cold fluid (water) is varied from 1.7-3 L/min and flow rates of the hot fluid is varied between 2-3.5 L/min. Thermal conductivity, density and viscosity of the nanofluids were also measured as a function of temperature and CNT concentration. The experimental results are validated with theoretical correlations for turbulent flow available in the literature. Results showed an enhancement in heat transfer range between 9-67% as a function of temperature and CNT concentration.

Keywords: nanofluids, carbon nanotubes (CNT), heat transfer enhancement, heat transfer

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Authors: A. Kudrev

Abstract:

The duplex Poly(A)-Poly(U) denaturation in an aqueous solutions in mixtures with the tetracationic MeTMPyP4 (Me = 2H, Zn(II); TMPyP4 is 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin), was investigated by monitoring the changes in the UV-Vis absorbance spectrum with increasing temperatures from 20°С to 70°С (рН 7.0, I=0.15M). The absorbance data matrices were analyzed with a versatile chemometric procedure that provides the melting profile (distribution of species) and the pure spectrum for each chemical species present along the heating experiment. As revealed by the increase of Tm, the duplex structure was stabilized by these porphyrins. The values of stabilization temperature ΔTm in the presence of these porphyrins are relatively large, 1.2-8.4 °C, indicating that the porphyrins contribute differently in stabilizing the duplex Poly(A)-Poly(U) structure. Remarkable is the fact that the porphyrin TMPyP4 was less effective in the stabilization of the duplex structure than the metalloporphyrin Zn(X)TMPyP4 which suggests that metallization play an important role in porphyrin-RNA binding. Molecular Dynamics Simulations has been used to illustrate melting of the duplex dsRNA bound with a porphyrin molecule.

Keywords: melting, Poly(A)-Poly(U), TMPyP4, Zn(X)TMPyP4

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Authors: Martins Olatunbosun Babatunde, Muhammed Bashir Muazu, Emmanuel Adewale Adedokun

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This paper presents the development of a double-loop trajectory-tracking controller for the ball and plate system (BPS) using the Normalized Right Coprime Factorization (NRCF) scheme.The Linear Algebraic (LA) method is used to design the inner loop required to stabilize the ball, while H-infinity NRCF method, that involved the lead-lag compensator design approach, is used to develop the outer loop that controls the plate. Simulation results show that the plate was stabilized at 0.2989 seconds and the ball was able to settle after 0.9646 seconds, with a trajectory tracking error of 0.0036. This shows that the controller has good adaptability and robustness.

Keywords: ball and plate system, normalized right coprime factorization, linear algebraic method, compensator, controller, tracking.

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Authors: Koo-Yeon Kim, Eun-Hye Kim, Tae-Il Son

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Epidermal Growth Factor (EGF, Mw=6,045) has been reported to have high efficiency of wound repair and anti-wrinkle effect. However, the half-life of EGF in the body is too short to exert the biological activity effectively when applied in free form. Growth Factors can be stabilized by immobilization with carbohydrates from thermal and proteolytic degradation. Low molecular weight chitosan (LMCS) and its derivate prepared by hydrogen peroxide has high solubility. LM6A6DC was successfully prepared as a reactive carbohydrate for the stabilization of EGF by the reactions of LMCS with alkalization, tosylation, azidation and reduction. The structure of LM6A6DC was confirmed by FT-IR, 1H NMR and elementary analysis. For enhancing the stability of free EGF, EGF was attached with LM6A6DC by using water-soluble carbodiimide. EGF-LM6A6DC conjugates did not show any cytotoxicity on the Normal Human Dermal Fibroblast(NHDF) 3T3 proliferation at least under 100 ㎍/㎖. In the result, it was considered that LM6A6DC is suitable to immobilize of growth factor.

Keywords: epidermal growth factor (EGF), low-molecular-weight chitosan, immobilization

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Authors: Muhammad Qadir, Yuncang Li, Cuie Wen

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Surface properties such as topography and physicochemistry of metallic implants determine the cell behavior. The surface of titanium (Ti)-based implant can be modified to enhance the bioactivity and biocompatibility. In this study, a self-organized titania–niobium pentoxide–zirconia (TiO₂–Nb₂O₅–ZrO₂) nanotubular layer on β phase Ti35Zr28Nb alloy was fabricated via electrochemical anodization. Energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement techniques were used to investigate the nanotubes dimensions (i.e., the inner and outer diameters, and wall thicknesses), microstructural features and evolution of the hydrophilic properties. The in vitro biocompatibility of the TiO₂–Nb₂O₅–ZrO₂ nanotubes (NTs) was assessed by using osteoblast cells (SaOS2). Influence of anodization parameters on the morphology of TiO₂–Nb₂O₅–ZrO₂ NTs has been studied. The results indicated that the average inner diameter, outer diameter and the wall thickness of the TiO₂–Nb₂O₅–ZrO₂ NTs were ranged from 25–70 nm, 45–90 nm and 5–13 nm, respectively, and were directly influenced by the applied voltage during anodization. The average inner and outer diameters of NTs increased with increasing applied voltage, and the length of NTs increased with increasing anodization time and water content of the electrolyte. In addition, the size distribution of the NTs noticeably affected the hydrophilic properties and enhanced the biocompatibility as compared with the uncoated substrate. The results of this study could be considered for developing nano-scale coatings for a wide range of biomedical applications.

Keywords: Titanium alloy, TiO₂–Nb₂O₅–ZrO₂ nanotubes, anodization, surface wettability, biocompatibility

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Authors: V. K. Stalin, M. Kirithika, K. Shanmugam, K. Tharini

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Nanotechnology has been widely used in many applications such as medical, electronics, robotics and also in geotechnical engineering area through stabilization of bore holes, grouting etc. In this paper, an attempt is made for understanding the influence of nano copper slag (1%, 2% & 3%) on the index, compaction and UCC strength properties of natural soil (CH type) with and without lime stabilization for immediate and 7 days curing period. Results indicated that upto 1% of Nano copper slag, there is an increment in UC strength of virgin soil and lime stabilised soil. Beyond 1% nano copper slag, there is a steep reduction in UC strength and increase of plasticity both in lime stabilised soil and virgin soil. The effect of lime is found to show more influence on large surface area of nano copper slag in natural soil. For both immediate and curing effect, with 1% of Nano copper slag, the maximum unconfined compressive strength was 38% and 106% higher than that of the virgin soil strength.

Keywords: lime, nano copper slag, SEM, XRD, stabilisation

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Authors: Rainer Goetz, Zahra Ahaliabadeh, Princess S. Llanos, Aliaksandr S. Bandarenka, Tanja Kallio

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In order to understand the electrochemistry of all-solid-state batteries (ASSBs), the use of electrochemical equivalent circuits with a physical meaning is essential. A model battery is needed whose characterization is independent of the influence of the complex battery assembly. Lithium-Ion Conducting Glass-Ceramic (LICGC), a model solid electrolyte, is chosen for its stability in the air, but on the other hand, it is also well-known for its instability against metallic lithium upon direct contact. Hence, as a first step towards a model ASSB, the interface between lithium and the solid electrolyte (SE) is stabilized with thin (5 nm and 10 nm) coatings of titanium oxide (TO) and lithium titanium oxide (LTO). Impedance data shows that both materials are able to protect the SE surface from rapid degradation due to reducing lithium and, therefore, can serve as a protective interlayer on the anode side of a model ASSB.

Keywords: all-solid-state battery, lithium anode, solid electrolytes, interlayers

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Authors: Armin Rahmatfam, Mohammad Zehsaz, Farid Vakili Tahami, Nasser Ghassembaglou

Abstract:

In this paper the thermal ratcheting, kinematic hardening parameters C, γ, isotropic hardening parameters and also k, b, Q combined isotropic/kinematic hardening parameters have been obtained experimentally from the monotonic, strain controlled cyclic tests at room and elevated temperatures of 20°C, 100°C, and 400°C. These parameters are used in nonlinear combined isotropic/kinematic hardening model to predict better description of the loading and reloading cycles in the cyclic indentation as well as thermal ratcheting. For this purpose, three groups of specimens made of Aluminum 7075-T6 have been investigated. After each test and using stable hysteretic cycles, material parameters have been obtained for using in combined nonlinear isotropic/kinematic hardening models. Also the methodology of obtaining the correct kinematic/isotropic hardening parameters is presented.

Keywords: combined hardening model, kinematic hardening, isotropic hardening, cyclic tests

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Authors: Md. Jahoor Alam

Abstract:

Recent studies suggest that Glucose controls several lifesaving pathways. Glucose molecule is reported to be responsible for the production of ROS (reactive oxygen species). In the present work, a p53-MDM2-Glucose model is developed in order to study spatiotemporal properties of the p53 pathway. The systematic model is mathematically described. The model is numerically simulated using high computational facility. It is observed that the variation in glucose concentration level triggers the system at different states, namely, oscillation death (stabilized), sustain and damped oscillations which correspond to various cellular states. The transition of these states induced by glucose is phase transition-like behaviour. Further, the amplitude of p53 dynamics with the variation of glucose concentration level follows power law behaviour, As(k) ~ kϒ, where, ϒ is a constant. Further Stochastic approach is needed for understanding of realistic behaviour of the model. The present model predicts the variation of p53 states under the influence of glucose molecule which is also supported by experimental facts reported by various research articles.

Keywords: oscillation, temporal behavior, p53, glucose

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