Search results for: functional properties

Authors: Hamed K. Arzani, Ahmad Amiri, Hamid K. Arzani, Salim Newaz Kazi, Ahmad Badarudin

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The new design of heat exchangers utilizing an annular distributor opens a new gateway for realizing higher energy optimization. To realize this goal, graphene nanoplatelet-based water nanofluids with promising thermophysical properties were synthesized in the presence of covalent and noncovalent functionalization. Thermal conductivity, density, viscosity and specific heat capacity were investigated and employed as a raw data for ANSYS-Fluent to be used in two-phase approach. After validation of obtained results by analytical equations, two special parameters of convective heat transfer coefficient and pressure drop were investigated. The study followed by studying other heat transfer parameters of annular pass in the presence of graphene nanopletelesbased water nanofluids at different weight concentrations, input powers and temperatures. As a result, heat transfer performance and friction loss are predicted for both synthesized nanofluids.

Keywords: heat transfer, nanofluid, turbulent flow, forced convection flow, graphene nanoplatelet

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Authors: Mostafa Rezaee Saraji, Ali Keshavarz Panahi

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In this work, the processing steps for producing alumina parts using powder injection molding (PIM) technique and nano-powder were investigated and the thermal conductivity and flexural strength of samples were determined as a function of sintering temperature and holding time. In the first step, the feedstock with 58 vol. % of alumina nano-powder with average particle size of 100nm was prepared using Extrumixing method to obtain appropriate homogeneity. This feedstock was injection molded into the two cavity mold with rectangular shape. After injection molding step, thermal and solvent debinding methods were used for debinding of molded samples and then these debinded samples were sintered in different sintering temperatures and holding times. From the results, it was found that the flexural strength and thermal conductivity of samples increased by increasing sintering temperature and holding time; in sintering temperature of 1600ºC and holding time of 5h, the flexural strength and thermal conductivity of sintered samples reached to maximum values of 488MPa and 40.8 W/mK, respectively.

Keywords: alumina nano-powder, thermal conductivity, flexural strength, powder injection molding

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Authors: Bilge Ozel

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Cities are high-complex living organisms and are subjects to continuous transformations produced by the stress that derives from changing conditions. Today the metropolises are seen like “development engines” of the countries and accordingly they become the centre of better living conditions that encourages demographic growth which constitutes the main reason of the changes. Indeed, the potential for economic advancement of the cities directly represents the economic status of their countries. The term of “resilience”, which sees the changes as natural processes and represents the flexibility and adaptability of the systems in the face of changing conditions, becomes a key concept for the development of urban transformation policies. The term of “resilience” derives from the Latin word ‘resilire’, which means ‘bounce’, ‘jump back’, refers to the ability of a system to withstand shocks and still maintain the basic characteristics. A resilient system does not only survive the potential risks and threats but also takes advantage of the positive outcomes of the perturbations and ensures adaptation to the new external conditions. When this understanding is taken into the urban context - or rather “urban resilience” - it delineates the capacity of cities to anticipate upcoming shocks and changes without undergoing major alterations in its functional, physical, socio-economic systems. Undoubtedly, the issue of coordinating the urban systems in a “resilient” form is a multidisciplinary and complex process as the cities are multi-layered and dynamic structures. The concept of “urban transformation” is first launched in Europe just after World War II. It has been applied through different methods such as renovation, revitalization, improvement and gentrification. These methods have been in continuous advancement by acquiring new meanings and trends over years. With the effects of neoliberal policies in the 1980s, the concept of urban transformation has been associated with economic objectives. Subsequently this understanding has been improved over time and had new orientations such as providing more social justice and environmental sustainability. The aim of this research is to identify the most applied urban transformation methods in Turkey and its main reasons of being selected. Moreover, investigating the lacking and limiting points of the urban transformation policies in the context of “urban resilience” in a comparative way with European interventions. The emblematic examples, which symbolize the breaking points of the recent evolution of urban transformation concepts in Europe and Turkey, are chosen and reviewed in a critical way.

Keywords: resilience, urban dynamics, urban resilience, urban transformation

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Authors: Samiul Islam Hazarika, Domngam Boje, Ananta Kumar Atta

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It is well familiar that solvents play a significant role in modern chemistry. Solvents can change the reactivity and physicochemical properties of molecules in a solution. Keeping this in mind, we have designed and synthesized a mono-triazolyl-linked pyrenyl-appended xylofuranose derivative for the detection of metal ions with changing solvent systems. The incorporation of a sugar backbone in the sensor increases the water solubility and biocompatibility. The experimental study revealed that the xylofuranose-based fluorescence probe did not exhibit any specific selectivity towards metal ions in acetonitrile (CH₃CN) solvent. Whereas, we revealed that triazole-linked pyrenyl-appended xylofuranose-based fluorescent sensor would exhibit high selectivity and sensitivity towards Au³⁺ ions in CH₃CN-H₂O (1/1, v/v) system. This observation might be explained by the viscosity and polarity differences of CH₃CN and CH₃CN-H₂O solvent systems. The formation of the sensor-Au³⁺ complex was also established by high-resolution mass spectrometry (HRMS) data of the complex.

Keywords: triazole, furanose, fluorometric, solvent dependent

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Authors: Monika Kamocka, Radoslaw Mania

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The design of Fiber Metal Laminates - combining thin aluminum sheets and prepreg layers, allows creating a hybrid structure with high strength to weight ratio. This feature makes FMLs very attractive for aerospace industry, where thin-walled structures are commonly used. Nevertheless, those structures are prone to buckling phenomenon. Buckling could occur also under static load as well as dynamic pulse loads. In this paper, the problem of dynamic buckling of open cross-section FML profiles under axial dynamic compression in the form of pulse load of finite duration is investigated. In the numerical model, material properties of FML constituents were assumed as nonlinear elastic-plastic aluminum and linear-elastic glass-fiber-reinforced composite. The influence of pulse shape was investigated. Sinusoidal and rectangular pulse loads of finite duration were compared in two ways, i.e. with respect to magnitude and force pulse. The dynamic critical buckling load was determined based on Budiansky-Hutchinson, Ari Gur, and Simonetta dynamic buckling criteria.

Keywords: dynamic buckling, dynamic stability, Fiber Metal Laminate, Finite Element Method

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Authors: Miaomiao Zhang, Sabrina Beckmann, Haluk Ertan, Rocky Chau, Mike Manefield

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Phenazines are a large class of nitrogen-containing aromatic heterocyclic compounds, which are almost exclusively produced by bacteria from diverse genera including Pseudomonas and Streptomyces. Phenazine-1-carboxylic acid (PCA) as one of 'core' phenazines are converted from chorismic acid before modified to other phenazine derivatives in different cells. Phenazines have attracted enormous interests because of their multiple roles on biocontrol, bacterial interaction, biofilm formation and fitness of their producers. However, in spite of ecological importance, degradation as a part of phenazines’ fate only have extremely limited attention now. Here, to isolate PCA-degrading bacteria, 200 mg L-1 PCA was supplied as sole carbon, nitrogen and energy source in minimal mineral medium. Quantitative PCR and Reverse-transcript PCR were employed to study abundance and activity of functional gene MFORT 16269 in PCA degradation, respectively. Intermediates and products of PCA degradation were identified with LC-MS/MS. After enrichment and isolation, a PCA-degrading strain was selected from soil and was designated as Rhodanobacter sp. PCA2 based on full 16S rRNA sequencing. As determined by HPLC, strain PCA2 consumed 200 mg L-1 (836 µM) PCA at a rate of 17.4 µM h-1, accompanying with significant cells yield from 1.92 × 105 to 3.11 × 106 cells per mL. Strain PCA2 was capable of degrading other phenazines as well, including phenazine (4.27 µM h-1), pyocyanin (2.72 µM h-1), neutral red (1.30 µM h-1) and 1-hydroxyphenazine (0.55 µM h-1). Moreover, during the incubation, transcript copies of MFORT 16269 gene increased significantly from 2.13 × 106 to 8.82 × 107 copies mL-1, which was 2.77 times faster than that of the corresponding gene copy number (2.20 × 106 to 3.32 × 107 copies mL-1), indicating that MFORT 16269 gene was activated and played roles on PCA degradation. As analyzed by LC-MS/MS, decarboxylation from the ring structure was determined as the first step of PCA degradation, followed by cleavage of nitrogen-containing ring by dioxygenase which catalyzed phenazine to nitrosobenzene. Subsequently, phenylhydroxylamine was detected after incubation for two days and was then transferred to aniline and catechol. Additionally, genomic and proteomic analyses were also carried out for strain PCA2. Overall, the findings presented here showed that a newly isolated strain Rhodanobacter sp. PCA2 was capable of degrading phenazines through decarboxylation and cleavage of nitrogen-containing ring, during which MFORT 16269 gene was activated and played important roles.

Keywords: decarboxylation, MFORT16269 gene, phenazine-1-carboxylic acid degradation, Rhodanobacter sp. PCA2

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Authors: Muhamad Azani Yahya, Umi Nadiah Nor Ali, Mohammed Alias Yusof, Norazman Mohamad Nor, Vikneswaran Munikanan

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In construction, concrete is one of the materials that can commonly be used as for structural elements. Concrete consists of cement, sand, aggregate and water. Concrete can be added with admixture in the wet condition to suit the design purpose such as to prolong the setting time to improve workability. For strength improvement, concrete is being added with other hybrid materials to increase strength; this is because the tensile strength of concrete is very low in comparison to the compressive strength. This paper shows the usage of a waterproofing agent in concrete to enhance the tensile strength. High tensile concrete is expensive because the concrete mix needs fiber and also high cement content to be incorporated in the mix. High tensile concrete being used for structures that are being imposed by high impact dynamic load such as blast loading that hit the structure. High tensile concrete can be defined as a concrete mix design that achieved 30%-40% tensile strength compared to its compression strength. This research evaluates the usage of a waterproofing agent in a concrete mix as an element of reinforcement to enhance the tensile strength. According to the compression and tensile test, it shows that the concrete mix with a waterproofing agent enhanced the mechanical properties of the concrete. It is also show that the composite concrete with waterproofing is a high tensile concrete; this is because of the tensile is between 30% and 40% of the compression strength. This mix is economical because it can produce high tensile concrete with low cost.

Keywords: high tensile concrete, waterproofing agent, concrete, rheology

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Authors: Maxence Queyrel, Edi Prifti, Alexandre Templier, Jean-Daniel Zucker

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Analysis of the human microbiome using metagenomic sequencing data has demonstrated high ability in discriminating various human diseases. Raw metagenomic sequencing data require multiple complex and computationally heavy bioinformatics steps prior to data analysis. Such data contain millions of short sequences read from the fragmented DNA sequences and stored as fastq files. Conventional processing pipelines consist in multiple steps including quality control, filtering, alignment of sequences against genomic catalogs (genes, species, taxonomic levels, functional pathways, etc.). These pipelines are complex to use, time consuming and rely on a large number of parameters that often provide variability and impact the estimation of the microbiome elements. Training Deep Neural Networks directly from raw sequencing data is a promising approach to bypass some of the challenges associated with mainstream bioinformatics pipelines. Most of these methods use the concept of word and sentence embeddings that create a meaningful and numerical representation of DNA sequences, while extracting features and reducing the dimensionality of the data. In this paper we present an end-to-end approach that classifies patients into disease groups directly from raw metagenomic reads: metagenome2vec. This approach is composed of four steps (i) generating a vocabulary of k-mers and learning their numerical embeddings; (ii) learning DNA sequence (read) embeddings; (iii) identifying the genome from which the sequence is most likely to come and (iv) training a multiple instance learning classifier which predicts the phenotype based on the vector representation of the raw data. An attention mechanism is applied in the network so that the model can be interpreted, assigning a weight to the influence of the prediction for each genome. Using two public real-life data-sets as well a simulated one, we demonstrated that this original approach reaches high performance, comparable with the state-of-the-art methods applied directly on processed data though mainstream bioinformatics workflows. These results are encouraging for this proof of concept work. We believe that with further dedication, the DNN models have the potential to surpass mainstream bioinformatics workflows in disease classification tasks.

Keywords: deep learning, disease prediction, end-to-end machine learning, metagenomics, multiple instance learning, precision medicine

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Authors: O. P. Popoola, O. A. Alawode, M. O. Olayiwola, A. M. Oladele

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This research work is based on using discriminant analysis to forecast crime rate in Nigeria between 1996 and 2008. The work is interested in how gender (male and female) relates to offences committed against the government, against other properties, disturbance in public places, murder/robbery offences and other offences. The data used was collected from the National Bureau of Statistics (NBS). SPSS, the statistical package was used to analyse the data. Time plot was plotted on all the 29 offences gotten from the raw data. Eigenvalues and Multivariate tests, Wilks’ Lambda, standardized canonical discriminant function coefficients and the predicted classifications were estimated. The research shows that the distribution of the scores from each function is standardized to have a mean O and a standard deviation of 1. The magnitudes of the coefficients indicate how strongly the discriminating variable affects the score. In the predicted group membership, 172 cases that were predicted to commit crime against Government group, 66 were correctly predicted and 106 were incorrectly predicted. After going through the predicted classifications, we found out that most groups numbers that were correctly predicted were less than those that were incorrectly predicted.

Keywords: discriminant analysis, DA, multivariate analysis of variance, MANOVA, canonical correlation, and Wilks’ Lambda

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Authors: Ajay Dwivedi, M. Suresh Kumar, A. N. Vaidya

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The problem of fruit and vegetable waste management is a grave one and with ever increasing need to feed the exponentially growing population, more and more solid waste in the form of fruit and vegetables waste are generated and its management has become one of the key issues in protection of environment. Energy generation from fruit and vegetables waste by dark anaerobic fermentation is a recent an interesting avenue effective management of solid waste as well as for generating free and cheap energy. In the present study 17 vegetables were characterized for their physical as well as chemical properties, these characteristics were used to determine the hydrogen and methane potentials of vegetable from various models, and also lab scale batch experiments were performed to determine their actual hydrogen and methane production capacity. Lab scale batch experiments proved that vegetable waste can be used as effective substrate for bio hydrogen and methane production, however the expected yield of bio hydrogen and methane was much lower than predicted by models, this was due to the fact that other vital experimental parameters such as pH, total solids content, food to microorganism ratio was not optimized.

Keywords: vegetable waste, physico-chemical characteristics, hydrogen, methane

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Authors: Laura M. Hovsepyan, Gayane S. Ghazaryan, Hasmik V. Zanginyan

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Hypertension (HD) is the most common cardiovascular pathology that causes disability and mortality in the working population. Most often, heart failure (HF), which is based on myocardial remodeling, leads to death in hypertension. Recently, endothelial dysfunction (EDF) or a violation of the functional state of the vascular endothelium has been assigned a significant role in the structural changes in the myocardium and the occurrence of heart failure in patients with hypertension. It has now been established that tissues affected by inflammation form increased amounts of superoxide radical and NO, which play a significant role in the development and pathogenesis of various pathologies. They mediate inflammation, modify proteins and damage nucleic acids. The aim of this work was to study the processes of oxidative modification of proteins (OMP) and the production of nitric oxide in hypertension. In the experimental work, the blood of 30 donors and 33 patients with hypertension was used. For the quantitative determination of OMP products, the based on the reaction of the interaction of oxidized amino acid residues of proteins and 2,4-dinitrophenylhydrazine (DNPH) with the formation of 2,4-dinitrophenylhydrazones, the amount of which was determined spectrophotometrically. The optical density of the formed carbonyl derivatives of dinitrophenylhydrazones was recorded at different wavelengths: 356 nm - aliphatic ketone dinitrophenylhydrazones (KDNPH) of neutral character; 370 nm - aliphatic aldehyde dinirophenylhydrazones (ADNPH) of neutral character; 430 nm - aliphatic KDNFG of the main character; 530 nm - basic aliphatic ADNPH. Nitric oxide was determined by photometry using Grace's solution. Adsorption was measured on a Thermo Scientific Evolution 201 SF at a wavelength of 546 nm. Thus, the results of the studies showed that in patients with arterial hypertension, an increased level of nitric oxide in the blood serum is observed, and there is also a tendency to an increase in the intensity of oxidative modification of proteins at a wavelength of 270 nm and 363 nm, which indicates a statistically significant increase in aliphatic aldehyde and ketone dinitrophenylhydrazones. The increase in the intensity of oxidative modification of blood plasma proteins in the studied patients, revealed by us, actually reflects the general direction of free radical processes and, in particular, the oxidation of proteins throughout the body. A decrease in the activity of the antioxidant system also leads to a violation of protein metabolism. The most important consequence of the oxidative modification of proteins is the inactivation of enzymes.

Keywords: hypertension (HD), oxidative modification of proteins (OMP), nitric oxide (NO), oxidative stress

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Authors: Meltem Nur Erdöl, Feyzanur Bayrak, Elif Emanetçi, Faik Nüzhet Oktar, Cevriye Kalkandelen, Oğuzhan Gündüz

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Nowadays, the bioceramic graft applications are very important due to the fact that especially European population is getting much older. Consequently, healing approaches for some health problems become more important in the near future. For instance, osteoporosis is one of the reasons for serious hip fractures. Beside these, the traffic accidents playing role increasing of various hip fractures and other bone fractures. Naturally all these are leading the importance developing new bioceramic graft materials. Hydroxyapatite (HA) is one of the leading bioceramics on the market. Beside the high biocompatibility HA bioceramics unfortunately are weak materials for loaded areas. For improvement mechanical properties of HA material, some oxides and metallic powders can be added. In this study, some rare earth oxides like hafnium (IV) oxide (HfO₂) and samarium (III) oxide (Sm₂O₃) are added to HA for improvement of their material characteristics. Thus, compression, microhardness and theoretical density tests are performed. X-ray diffraction patterns are also investigated corresponding x-ray diffraction equipment. At the end, studies of scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDX) are completed. All values were compared with past BHA and various composites.

Keywords: biocomposite, hafnium oxide, hydroxyapatite, nanotechnology, samarium oxide

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Authors: Priti Saha, Biswajit Paul

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Rapid urbanization and industrialization has increased the pollution load in surface water bodies. However, these water bodies are major source of water for drinking, irrigation, industrial activities and fishery. Therefore, water quality assessment is paramount importance to evaluate its suitability for all these purposes. This study focus to evaluate the surface water quality of an industrial city in eastern India through integrating interdisciplinary techniques. The multi-purpose Water Quality Index (WQI) assess the suitability for drinking, irrigation as well as fishery of forty-eight sampling locations, where 8.33% have excellent water quality (WQI:0-25) for fishery and 10.42%, 20.83% and 45.83% have good quality (WQI:25-50), which represents its suitability for drinking irrigation and fishery respectively. However, the industrial water quality was assessed through Ryznar Stability Index (LSI), which affirmed that only 6.25% of sampling locations have neither corrosive nor scale forming properties (RSI: 6.2-6.8). Integration of these statistical analysis with geographical information system (GIS) helps in spatial assessment. It identifies of the regions where the water quality is suitable for its use in drinking, irrigation, fishery as well as industrial activities. This research demonstrates the effectiveness of statistical and GIS techniques for water quality assessment.

Keywords: surface water, water quality assessment, water quality index, spatial assessment

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Authors: Arpan Kumar Nayak, Debabrata Pradhan

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A simple, single-step and one-pot hydrothermal method was employed to synthesize WO₃-SnO₂ mixed nanostructured metal oxides at 200°C in 12h. The SnO₂ nanoparticles were found to be uniformly decorated on the WO₃ nanoplates. Though it is widely known that noble metals such as Pt, Pd doping or decoration on metal oxides improve the sensing response and sensitivity, we varied the SnO₂ concentration in the WO₃-SnO₂ mixed oxide and demonstrated their performance in ammonia, ethanol and acetone sensing. The sensing performance of WO₃-(x)SnO₂ [x = 0.27, 0.54, 1.08] mixed nanostructured oxides was found to be not only superior to that of pristine oxides but also higher/better than that of reported noble metal-based sensors. The sensing properties (selectivity, limit of detection, response and recovery times) are measured as a function of operating temperature (150-350°C). In particular, the gas selectivity is found to be highly temperature-dependent with optimum performance obtained at 200°C, 300°C and 350°C for ammonia, ethanol, and acetone, respectively. The present results on cost effective WO₃-SnO₂ sensors can find potential application in human breath analysis by noninvasive detection.

Keywords: gas sensing, mixed oxides, nanoplates, ammonia, ethanol, acetone

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Authors: Elmira Davasaz Tabrizi, Müşteba Sevil, Ercan Arican

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In recent decades, there has been a sharp increase in the prevalence of several unrelated chronic diseases. The use of long-term antibiotics for chronic illnesses is increasing. The antibiotic resistance occurrence and its relationship with host microbiomes are still unclear. Properties of the identifying antibodies have been the focus of chronic disease research, such as prostatitis or autoimmune. The immune system is made up of a complicated but well-organized network of cell types that constantly monitor and maintain their surroundings. The regulated homeostatic interaction between immune system cells and their surrounding environment shapes the microbial flora. Researchers believe that the disappearance of special bacterial species from our ancestral microbiota might have altered the body flora that can cause a rise in disease during the human life span. This unpleasant pattern demonstrates the importance of focusing on discovering and revealing the root causes behind the disappearance or alteration of our microbiota. In this review, we gathered the results of some studies that reveal changes in the diversity and quantity of microorganisms that may affect chronic and autoimmune diseases. Additionally, a Ph.D. thesis that is still in process as Metagenomic studies in chronic prostatitis samples is mentioned.

Keywords: metagenomic, autoimmune, prostatitis, microbiome

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Authors: A. Sharma, S. S. Sandhu, A. Shahi, A. Kumar

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The aim of present investigation was to carry out Finite element modeling of distortion in the case of butt weld. 12mm thick AISI 304L plates were butt welded using three different combinations of groove design namely Double U, Double V and Composite. A full simulation of shielded metal arc welding (SMAW) of nonlinear heat transfer is carried out. Aspects like, temperature-dependent thermal properties of AISI stainless steel above liquid phase, the effect of thermal boundary conditions, were included in the model. Since welding heat dissipation characteristics changed due to variable groove design significant changes in the microhardness tensile strength and impact toughness of the joints were observed. The cumulative distortion was found to be least in double V joint followed by the Composite and Double U-joints. All the joints have joint efficiency more than 100%. CVN value of the Double V-groove weld metal was highest. The experimental results and the FEM results were compared and reveal a very good correlation for distortion and weld groove design for a multipass joint with a standard analogy of 83%.

Keywords: AISI 304 L, Butt joint, distortion, FEM, groove design, SMAW

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Authors: Noshaba Dilbar, Maria Jabbar

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Medicinal plants are considered to be the richest source of drug discovery. The main cause of medicinal properties of plants is the presence of bioactive compounds in them. Phytochemical screening is the valuable process that detects bioactive compounds(secondary metabolites) in plants. The present study was carried out to determine phytochemical profile and ethnobotanical importance of Capparidaceae species. ( Capparis spinosa and Dipterygium glaucum). The selection of plants was made on basis of traditional knowledge of their usage in ayurvedic medicines. Different type of solvents(ethanol, methanol, chloroform, benzene and petroleum ether) were used to make extracts of dry and fresh plants. Phytochemical screening was made by using various standard techniques. Results reveal the presence of large range of bioactive compounds i.e alakloids, saponins, flavonoids, terpenoids, glycosides, phenols and steroids. Methanol, petroleum ether and chloroform extracts showed high extractability of bioactive compounds. The results obtained ensure these plants a reliable source of pharmacological industry and can be used in making of various biological friendly drugs.

Keywords: bioactive compounds, Capparidaceae, phytochemical screening, secondary metabolites

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Authors: Natural Frequency Analysis of a Porous Functionally Graded Shaft System

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The vibration characteristics of a functionally graded (FG) rotor model having porosities and micro-voids is investigated using three-dimensional finite element analysis. The FG shaft is mounted with a steel disc located at the midspan. The shaft ends are supported on isotropic bearings. The FG material is composed of a metallic (stainless-steel) and ceramic phase (zirconium oxide) as its constituent phases. The layer wise material property variation is governed by power law. Material property equations are developed for the porosity modelling. Python code is developed to assign the material properties to each layer including the effect of porosities. ANSYS commercial software is used to extract the natural frequencies and whirl frequencies for the FG shaft system. The obtained results show the influence of porosity volume fraction and power-law index, on the vibration characteristics of the ceramic-based FG shaft system.

Keywords: Finite element method, Functionally graded material, Porosity volume fraction, Power law

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Authors: Hexiong Liu

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Powder metallurgy is the optimal method for the consolidation and preparation of W(Mo) alloys, which exhibit excellent application prospects at high temperatures. The properties of W(Mo) alloys are closely related to the sintered density. However, controlling the sintered density and porosity of these alloys is still challenging. In the past, the regulation methods mainly focused on time-consuming and costly trial-and-error experiments. In this study, the sintering data for more than a dozen W(Mo) alloys constituted a small-scale dataset, including both solid and liquid phases of sintering. Furthermore, simple descriptors were used to predict the sintered density of W(Mo) alloys based on the descriptor selection strategy and machine learning method (ML), where the ML algorithm included the least absolute shrinkage and selection operator (Lasso) regression, k-nearest neighbor (k-NN), random forest (RF), and multi-layer perceptron (MLP). The results showed that the interpretable descriptors extracted by our proposed selection strategy and the MLP neural network achieved a high prediction accuracy (R>0.950). By further predicting the sintered density of W(Mo) alloys using different sintering processes, the error between the predicted and experimental values was less than 0.063, confirming the application potential of the model.

Keywords: sintered density, machine learning, interpretable descriptors, W(Mo) alloy

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Authors: Yemi Mahmud

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Semiotics is the study of signs and symbols as significations in a communication process. Television advertisement combines verbal and nonverbal signs to apprise consumers of products’ deliverables. This makes the language of television advertisement an important area of semiotic research. This paper focuses on nonverbal signs in television advertisement in purposively selected advertisements of two Nivea beauty products television advertisements: New Nivea Natural Fairness and Nivea Natural Fairness Lotion in Nigeria to investigate signs in meaning construction. It studies the interpretative realities of the signification of the nonverbal signs in television advertisements in Nigeria; examining signs in relation to the embedded and contextual meanings they are capable of exhuming vis-a-vis, viewers’ social and cultural senses extrapolated to draw inferences. The paper anchors its research on visual rhetorics and concludes that signs, as nonverbal elements in television advertisements, form part of the entire linguistic system of meaning transmission, noting that interpretations do not rely, solely, on the intrinsic properties of signs as signifiers, but on the imbued sociocultural elements that suggest meaning to viewers.

Keywords: Nivea, nonverbal signs, semiotics, signification, signifiers, television advertisement

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Authors: Anas M. Fares

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Reinforced concrete shear walls are the most frequently used forms of lateral resisting structural elements. These walls may take many forms due to their functions and locations in the building. In Palestine, the most lateral resisting forces construction forms is the cantilever shear walls system. It is thus of prime importance to study the rigidity of these walls. The virtual work theorem is used to derive the total lateral deflection of cantilever shear walls due to flexural and shear deformation. The case of neglecting the shear deformation in the walls is also studied, and it is found that the wall height to length aspect ratio (H/B) plays a major role in calculating the lateral deflection and the rigidity of such walls. When the H/B is more than or equal to 3.7, the shear deformation may be neglected from the calculation of the lateral deflection. Moreover, the walls with the same material properties, same lateral load value, and same aspect ratio, shall have the same of both the lateral deflection and the rigidity. Finally, an equation to calculate the total rigidity and total deflection of such walls is derived by using the virtual work theorem for a cantilever beam.

Keywords: cantilever shear walls, flexural deformation, lateral deflection, lateral loads, reinforced concrete shear walls, rigidity, shear deformation, virtual work theorem

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Authors: Jiin-Yuh Jang, Yu-Feng Gan

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In order to improve the comprehensive mechanical properties of the steel, the cooling rate, and the temperature distribution must be controlled in the cooling process. A three-dimensional numerical model for the prediction of the heat transfer coefficient distribution of H-beam in the controlled cooling process was performed in order to obtain the uniform temperature distribution and minimize the maximum stress and the maximum deformation after the controlled cooling. An algorithm developed with a simplified conjugated-gradient method was used as an optimizer to optimize the heat transfer coefficient distribution. The numerical results showed that, for the case of air cooling 5 seconds followed by water cooling 6 seconds with uniform the heat transfer coefficient, the cooling rate is 15.5 (℃/s), the maximum temperature difference is 85℃, the maximum the stress is 125 MPa, and the maximum deformation is 1.280 mm. After optimize the heat transfer coefficient distribution in control cooling process with the same cooling time, the cooling rate is increased to 20.5 (℃/s), the maximum temperature difference is decreased to 52℃, the maximum stress is decreased to 82MPa and the maximum deformation is decreased to 1.167mm.

Keywords: controlled cooling, H-Beam, optimization, thermal stress

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Authors: I. Belbachir, T. Benabdallah, N. Belhadj

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The present research work describes the synthesis, through a multi-step strategy, as well as the structural characterization of a polydentate organic ligand, namely the bis(4-amino-5-mercapto-1,2,4-triazole-3-yl)butane (BAMT). The bis-triazolic ligand was characterized by different spectroscopic studies, in order to enlighten its coordination mode, in the neutral and deprotonated forms, towards cobalt(II), nickel(II) and copper(II) sulfates, in both solution and solid state. The stoichiometry of the complexes [neutral BAMT-metal] and [deprotonated BAMT-metal] was first established in a solution of DMF with each of the three metallic cations and their complexation constants calculated, allowing us to compare the stability of the various prepared complexes. The various complexes were finally isolated in the solid state and the coordination mode of neutral and deprotonated BAMT explored towards each of the three metallic sulfates. The establishment of some ligand field parameters (Dq, B, β…) by electronic spectroscopy finally allowed to compare the coordination modes of BAMT towards each of the three metals and to highlight the influence of the deprotonation on the complexing properties of the bis-triazolic ligand.

Keywords: 1, 2, 4-triazol, bis-1, 2, 4-triazol, metallic complexes, coordination in solution and solid state

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Authors: Fatmawati Adam, Saidatul Syaima Mat Tari, Saiful Nizam Tajuddin, Nurul Salwa Azliyana Hamzah

Abstract:

Essential oil of agarwood or known as Gaharu in Malay is highly prized for its value as luxury fragrances and incense. However, the complexities of the chemical composition of agarwood itself is the main challenge for establishment of an effective recovery method, which is able to ensure uniform qualities and standard for each batch of essential oil production. Agarwood markers are actually a blend of volatile and non-volatile compounds. While volatile molecules could be easily retrieved by the present distillation technique, the high solubility properties are the limiting factor for the latter. With regard to this, an elementary chemistry resolution study had been performed on commercial agarwood essential oil-water mixture, by the application of preparative HPLC and FTIR. Interpretation of the results leads to the theoretical postulation that, agarwood water mixture comprise of agarospirol, jinkohol, jinkoh eremol and khusenol. This study provides a pinpoint on the chemical characteristics of water soluble (non-volatile) agarwood compounds, therefore, will be an insight for researchers to develop a more strategic technique for their extraction. Thereafter the optimum quality of this essential oil could be controlled in a more improved way.

Keywords: Agarwood, Aquillaria Malaccensis, agarospirol, jinkohol, jinkoh eremol, khusenol

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Authors: Abhishek Ranka

Abstract:

Rock-cut Architecture is a manifestation of human endurance in constructing magnificent structures by sculpting and cutting entire hills. Cave Architecture in India form an important part of rock-cut development and is among the most prolific examples of rock-cut architecture in the world. There are more than 1500 rock-cut caves in various regions of India. Among them mostly are located in western India, more particularly in the state of Maharashtra. Some of the rock-cut caves are located in the central region of India, which is presently known as Malawa (Madhya Pradesh). The region is dominated by the vidhyachal hill ranges toward the west, dotted with the coarse laterite rock. Dhamnar Caves have been excavated in the central region of Mandsaur Dist. With a combination of shared sacred faiths. The earliest rock-cut activity began in the north, in Bihar, where caves were excavated in the Barabar and the Nagarjuni hills during the Mauryan period (3rd century BCE). The rock-cut activity then shifts to the central part of India in Madhya Pradesh, where the caves at Dhamnar, Bagh, Udayagiri, Poldungar, etc. excavated between 3rdto 9ᵗʰ CE. The rock-cut excavation continued to flourish in Madhya Pradesh till 10ᵗʰ century CE, simultaneously with monolithic Hindu temples. Dhamnar caves fall into four architectural typologies: the Lena caves, Chaitya caves, Viharas & Lena-Chaityagriha caves. The Buddhist rock-cutting activity in central India is divisible into two phases. In the first phase (2ndBCE-3rd CE), the Buddha image is conspicuously absent. After a lapse of about three centuries, activity begins again, and the Buddha images this time are carved. The former group belongs to the Hinayana (Lesser Vehicle) phase and the latter to the Mahayana (Greater Vehicle). Dhamnar caves has an elaborate facades, pillar capitals, and many more creative sculptures in various postures. These caves were excavated against the background of invigorating trade activities and varied socio-religious or Socio Cultural contexts. These caves also highlights the wealthy and varied patronage provided by the dynasties of the past. This paper speaks about the appraisal of the rock cut mechanisms, design strategies, and approaches while promoting a scope for further research in conservation practices. Rock-cut sites, with their physical setting and various functional spaces as a sustainable habitat for centuries, has a heritage footprint with a researchquotient.

Keywords: rock-cut architecture, buddhism, hinduism, Iconography, and architectural typologies, Jainism

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Authors: Md. Hasan Zahir

Abstract:

Y2O3-doped silica membranes were synthesized with the sol-gel method by using a tetraethyl orthosilicate-derived sol mixed with yttrium nitrate hexahydrate. These solutions were used to fabricate hydrogen separation microporous membranes with a sandwich-type structure on γ-Al2O3 supported by tubular α-Al2O3. Pore size distribution measurements were conducted directly on the membranes before and after hydrothermal treatment with a nano-permporometer. The gas permeance properties of the membranes were measured in the temperature range 100–500°C. The Y-doped SiO2 membrane (Si/Y = 3/1) was found to exhibit asymptotically stable permeances of 2.39×10-7 mol m-2 s -1 Pa-1 for He and 6.19 ×10-10 mol m-2 s -1 Pa-1 for CO2, with a high selectivity of 386 (He/CO2) at 500°C for 20 h in the presence of steam. The Y-doped silica membranes exhibit very high gas permeances for molecules with smaller kinetic diameters. The apparent activation energies of the H2 permeance at 400°C were 24.2±0.2 and 21.3±0.7 kJ mol−1 for SiO2 and Si/Y, respectively. Very high permeances were obtained for N2 and O2, 2.2 and 5 × 10-8 mol m-2 s -1 Pa-1 respectively, which demonstrates that these materials are promising air purification and/or separation systems that block larger impurity molecules by molecular sieving effects. Y-doped SiO2 exhibits greater hydrothermal stability at high temperatures and higher selectivity than SiO2 membranes.

Keywords: ceramic membrane, gas separation, hydrothermal stability, rare earth doped-Silica

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Authors: Paola Causin, Andrea Aspri, Alessandro Benfenati

Abstract:

Diffuse Optical Tomography (DOT) is an emergent medical imaging technique which employs NIR light to estimate the spatial distribution of optical coefficients in biological tissues for diagnostic purposes, in a noninvasive and non-ionizing manner. DOT reconstruction is a severely ill-conditioned problem due to prevalent scattering of light in the tissue. In this contribution, we present our research in adopting hybrid knowledgedriven/data-driven approaches which exploit the existence of well assessed physical models and build upon them neural networks integrating the availability of data. Namely, since in this context regularization procedures are mandatory to obtain a reasonable reconstruction [1], we explore the use of neural networks as tools to include prior information on the solution. 2. Materials and Methods The idea underlying our approach is to leverage neural networks to solve PDE-constrained inverse problems of the form 𝒒 ∗ = 𝒂𝒓𝒈 𝒎𝒊𝒏𝒒 𝐃(𝒚, 𝒚̃), (1) where D is a loss function which typically contains a discrepancy measure (or data fidelity) term plus other possible ad-hoc designed terms enforcing specific constraints. In the context of inverse problems like (1), one seeks the optimal set of physical parameters q, given the set of observations y. Moreover, 𝑦̃ is the computable approximation of y, which may be as well obtained from a neural network but also in a classic way via the resolution of a PDE with given input coefficients (forward problem, Fig.1 box ). Due to the severe ill conditioning of the reconstruction problem, we adopt a two-fold approach: i) we restrict the solutions (optical coefficients) to lie in a lower-dimensional subspace generated by auto-decoder type networks. This procedure forms priors of the solution (Fig.1 box ); ii) we use regularization procedures of type 𝒒̂ ∗ = 𝒂𝒓𝒈𝒎𝒊𝒏𝒒 𝐃(𝒚, 𝒚̃)+ 𝑹(𝒒), where 𝑹(𝒒) is a regularization functional depending on regularization parameters which can be fixed a-priori or learned via a neural network in a data-driven modality. To further improve the generalizability of the proposed framework, we also infuse physics knowledge via soft penalty constraints (Fig.1 box ) in the overall optimization procedure (Fig.1 box ). 3. Discussion and Conclusion DOT reconstruction is severely hindered by ill-conditioning. The combined use of data-driven and knowledgedriven elements is beneficial and allows to obtain improved results, especially with a restricted dataset and in presence of variable sources of noise.

Keywords: inverse problem in tomography, deep learning, diffuse optical tomography, regularization

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Authors: Fernanda A. Vechietti, Natália O. B. Muniz, Laura C. Treccani, Kurosch. Rezwan, Luis Alberto dos Santos

Abstract:

CoCr alloys are widely used in prosthetic implants due to their excellent mechanical properties, such as good tensile strength, elastic modulus and wear resistance. Their biocompatibility and lack of corrosion are also prominent features of this alloy. One of the most effective and simple ways to protect metal’s surfaces are treatments, such as electrochemical oxidation by passivation, which is used as a protect release of metallic ions. Another useful treatment is the electropolishing, which is used to reduce the carbide concentration and protrusion at the implanted surface. Electropolishing is a cheap and effective method for treatment of implants, which generally has complex geometries. The purpose of this study is surface modification of the alloy CoCr(ASTM F90-09) by different methods: polishing, electro polishing, passivation and heat treatment for application as biomaterials. The modification of the surface was studied and characterized by SEM, profilometry, wettability and compared to the surface of the samples untreated. The heat treatment and of passivation increased roughness (0.477 µm and 0.825 µm) the samples in relation the sample electropolished and polished(0.131 µm and 0.274 µm) and were observed the improve wettability’s with the increase the roughness.

Keywords: biomaterial, CoCr, surface treatment, heat treatment, roughness

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Authors: Truong Nguyen Luan Vu, Le Hieu Giang, Le Linh

Abstract:

The FOPI controller is proposed based on the main properties of the decoupling control scheme, as well as the fractional calculus. By using the simplified decoupling technique, the transfer function of decoupled apparent process is firstly separated into a set of n equivalent independent processes in terms of a ratio of the diagonal elements of original open-loop transfer function to those of dynamic relative gain array and the fraction – order PI controller is then developed for each control loops due to the Bode’s ideal transfer function that gives the desired fractional closed-loop response in the frequency domain. The simulation studies were carried out to evaluate the proposed design approach in a fair compared with the other existing methods in accordance with the structured singular value (SSV) theory that used to measure the robust stability of control systems under multiplicative output uncertainty. The simulation results indicate that the proposed method consistently performs well with fast and well-balanced closed-loop time responses.

Keywords: ideal transfer function of bode, fractional calculus, fractional order proportional integral (FOPI) controller, decoupling control system

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Authors: A. Olivi, P. Reyes Cabrera

Abstract:

Ageing and urbanization are two of the main trends that characterize the twenty-first century. Its trending is especially accelerated in the emerging countries of Asia and Latin America. Chile is one of the countries in the Latin American region, where the demographic transition to ageing is becoming increasingly visible. The challenges that the new demographic scenario poses to urban administrators call for searching innovative solutions to maximize the functional and psycho-social benefits derived from the relationship between older people and the environment in which they live. Although mobility is central to people's everyday practices and social relationships, it is not distributed equitably. On the contrary, it can be considered another factor of inequality in our cities. Older people are a particularly sensitive and vulnerable group to mobility. In this context, based on the ageing in place strategy and following the social innovation approach within a spatial context, the "Community Observatory of Territorial Information Control and Management" project aims at the collective search and validation of solutions for the satisfaction of mobility and accessibility specific needs of urban aged people. Specifically, the Observatory intends to: i) promote the direct participation of the aged population in order to generate relevant information on the territorial situation and the satisfaction of the mobility needs of this group; ii) co-create dynamic and efficient mechanisms for the reporting and updating of territorial information; iii) increase the capacity of the local administration to plan and manage solutions to environmental problems at the neighborhood scale. Based on a participatory mapping methodology and on the application of digital technology, the Observatory designed and developed, together with aged people, a crowdsourcing platform for smartphones, called DIMEapp, for reporting environmental problems affecting mobility and accessibility. DIMEapp has been tested at a prototype level in two neighborhoods of the city of Valparaiso. The results achieved in the testing phase have shown high potential in order to i) contribute to establishing coordination mechanisms with the local government and the local community; ii) improve a local governance system that guides and regulates the allocation of goods and services destined to solve those problems.

Keywords: accessibility, ageing, city, digital technology, local governance

Procedia PDF Downloads 115