Search results for: micro silica

Authors: Mirvat Shamseddine, Issam Lakkis

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We present an efficient, three-dimensional parallel multi-scale Direct Simulation Monte Carlo (DSMC) algorithm for the simulation of unsteady rarefied gas flows in micro/nanosystems. The algorithm employs a novel spatiotemporal adaptivity scheme. The scheme performs a fully dynamic multi-level grid adaption based on the gradients of flow macro-parameters and an automatic temporal adaptation. The computational domain consists of a hierarchical octree-based Cartesian grid representation of the flow domain and a triangular mesh for the solid object surfaces. The hybrid mesh, combined with the spatiotemporal adaptivity scheme, allows for increased flexibility and efficient data management, rendering the framework suitable for efficient particle-tracing and dynamic grid refinement and coarsening. The parallel algorithm is optimized to run DSMC simulations of strongly unsteady, non-equilibrium flows over multiple cores. The presented method is validated by comparing with benchmark studies and then employed to improve the design of micro-scale hotwire thermal sensors in rarefied gas flows.

Keywords: DSMC, oct-tree hierarchical grid, ray tracing, spatial-temporal adaptivity scheme, unsteady rarefied gas flows

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Authors: Ramin Khamedi, Isa Ahmadi

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In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).

Keywords: acoustic emission, dual phase steels, deformation, failure, fracture

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Authors: Simone Leonardi, Luca Ardito

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Micro-influencers are effective elements in the marketing strategies of companies and institutions because of their capability to create an hyper-engaged audience around a specific topic of interest. In recent years, many scientific approaches and commercial tools have handled the task of detecting this type of social media users. These strategies adopt solutions ranging from rule based machine learning models to deep neural networks and graph analysis on text, images, and account information. This work compares the existing solutions and proposes an ensemble method to generalize them with different input data and social media platforms. The deployed solution combines deep learning models on unstructured data with statistical machine learning models on structured data. We retrieve both social media accounts information and multimedia posts on Twitter and Instagram. These data are mapped into feature vectors for an eXtreme Gradient Boosting (XGBoost) classifier. Sixty different topics have been analyzed to build a rule based gold standard dataset and to compare the performances of our approach against baseline classifiers. We prove the effectiveness of our work by comparing the accuracy, precision, recall, and f1 score of our model with different configurations and architectures. We obtained an accuracy of 0.91 with our best performing model.

Keywords: deep learning, gradient boosting, image processing, micro-influencers, NLP, social media

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Authors: Dino Carpentras, Paul Maher, Caoimhe O'Reilly, Michael Quayle

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Opinion dynamics is dedicated to modeling the dynamic evolution of people's opinions. Models in this field are based on a micro-dynamic rule, which determines how people update their opinion when interacting. Despite the high number of new models (many of them based on new rules), little research has been dedicated to experimentally validate the rule. A few studies started bridging this literature gap by experimentally testing the rule. However, in these studies, participants are forced to express their opinion as a number instead of using natural language. Furthermore, some of these studies average data from experimental questions, without testing if differences existed between them. Indeed, it is possible that different topics could show different dynamics. For example, people may be more prone to accepting someone's else opinion regarding less polarized topics. In this work, we collected data from 200 participants on 5 unpolarized topics. Participants expressed their opinions using natural language ('agree' or 'disagree') and the certainty of their answer, expressed as a number between 1 and 10. To keep the interaction based on natural language, certainty was not shown to other participants. We then showed to the participant someone else's opinion on the same topic and, after a distraction task, we repeated the measurement. To produce data compatible with standard opinion dynamics models, we multiplied the opinion (encoded as agree=1 and disagree=-1) with the certainty to obtain a single 'continuous opinion' ranging from -10 to 10. By analyzing the topics independently, we observed that each one shows a different initial distribution. However, the dynamics (i.e., the properties of the opinion change) appear to be similar between all topics. This suggested that the same micro-dynamic rule could be applied to unpolarized topics. Another important result is that participants that change opinion tend to maintain similar levels of certainty. This is in contrast with typical micro-dynamics rules, where agents move to an average point instead of directly jumping to the opposite continuous opinion. As expected, in the data, we also observed the effect of social influence. This means that exposing someone with 'agree' or 'disagree' influenced participants to respectively higher or lower values of the continuous opinion. However, we also observed random variations whose effect was stronger than the social influence’s one. We even observed cases of people that changed from 'agree' to 'disagree,' even if they were exposed to 'agree.' This phenomenon is surprising, as, in the standard literature, the strength of the noise is usually smaller than the strength of social influence. Finally, we also built an opinion dynamics model from the data. The model was able to explain more than 80% of the data variance. Furthermore, by iterating the model, we were able to produce polarized states even starting from an unpolarized population. This experimental approach offers a way to test the micro-dynamic rule. This also allows us to build models which are directly grounded on experimental results.

Keywords: experimental validation, micro-dynamic rule, opinion dynamics, update rule

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Authors: Ismaila Haruna

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The global downfall in fossil energy prices and dwindling oil reserves in Nigeria has ignited interest in the search for alternative sources of foreign income for the country. Solid minerals, particularly Uranium and other base metals like Lead and Zinc have been considered as potentially good options. Several occurrences of this mineral have been discovered in both the sedimentary and granitic rocks of the Hawal and Adamawa Massifs as well as in the adjoining Benue Trough in northeastern Nigeria. However, the paucity of geochemical data and consequent poor petrogenetic knowledge of the granitoids in this region has made exploration works difficult. Song, a small area within the Hawal Massif, was mapped and the collected samples chemically determined in Activation Laboratory, Canada through fusion dissolution technique of Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Field mapping results show that the area is underlain by Granites, diorites with pockets of gneisses and pegmatites and that these rocks consists of microcline, quartz, plagioclase, biotite, hornblende, pyroxene and accessory apatite, zircon, sphene, magnetite and opaques in various proportions. Geochemical data show continous compositional variation from diorite to granites within silica range of 52.69 to 76.04 wt %. Plot of the data on various Harker variation diagrams show distinct evolutionary trends from diorites to granites indicated by decreasing CaO, Fe2O3, MnO, MgO, Ti2O, and increasing K2O with increasing silica. This pattern is reflected in trace elements data which, in general, decrease from diorite to the granites with rising Rb and K. Tectonic, triangular and other diagrams, indicate high-K calc-alkaline trends, syn-collisional granite signatures, I-type characteristics, with CNK/A of less than 1.1 (minimum of 0.58 and maximum of 0.94) and strong potassic character (K2O/Na2O˃1). However, only the granites are slightly peraluminous containing high silica percentage (68.46 to 76.04), K2O (2.71 to 6.16 wt %) with low CaO (1.88 on the average). Chondrite normalised rare earth elements trends indicate strongly fractionated REEs and enriched LREEs with slightly increasing negative Eu anomaly from the diorite to the granite. On the basis of field and geochemical data, the granitoids are interpreted to be high-K calc-alkaline, I-type, formed as a result of hybridization between mantle-derived magma and continental source materials (probably older meta-sediments) in a syn-collisional tectonic setting.

Keywords: geochemistry, granite, Hawal Massif, Nigeria, petrogenesis, song

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Authors: P. Bhavya, P. R. Jayasree

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This paper presents a low cost transformer isolated boost half bridge micro-inverter for single phase grid connected PV system. Since the output voltage of a single PV panel is as low as 20~50V, a high voltage gain inverter is required for the PV panel to connect to the single-phase grid. The micro-inverter has two stages, an isolated dc-dc converter stage and an inverter stage with a dc link. To achieve MPPT and to step up the PV voltage to the dc link voltage, a transformer isolated boost half bridge dc-dc converter is used. To output the synchronised sinusoidal current with unity power factor to the grid, a pulse width modulated full bridge inverter with LCL filter is used. Variable step size Maximum Power Point Tracking (MPPT) method is adopted such that fast tracking and high MPPT efficiency are both obtained. AC voltage as per grid requirement is obtained at the output of the inverter. High power factor (>0.99) is obtained at both heavy and light loads. This paper gives the results of computer simulation program of a grid connected solar PV system using MATLAB/Simulink and SIM Power System tool.

Keywords: boost-half-bridge, micro-inverter, maximum power point tracking, grid connection, MATLAB/Simulink

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Authors: Reza Nozadheravi, Masoud Hasanzade Novin

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Those techniques of translation which are engaged with short textual segments and mostly are prescriptive can be considered as micro level elements. Macro levels, however, refer to those translation strategies and those external factors that affect the translator’s decisions and have descriptive nature. What was scrutinized in details in the paper reveals the ‎macro-elements which are crucial in canonized translated texts, moreover, different aspects ‎of the patronage, which can be considered as the important factors from having the texts ‎chosen to the final translation products, have been observed in translated texts of Najaf ‎Darya-Bandarie, the well-known Iranian Translator. What is probed in this paper ‎reveals that marco-elements along with the linguistic aspects of the texts, micro-elements, ‎are considered as the significant aspects in translation process and even final translated ‎texts.

Keywords: canolized translated texts‎, culture‎, macro-elements‎, patronage

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Authors: Kai-Fen Tu, Jenn-Wen Huang, Yao-Tung Lin

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Cucumber is a major economic crop in the world. The global production of cucumber in 2017 was more than 71 million tonnes. Nonetheless, downy mildew, caused by Pseudoperonospora cubensis, is a devastating and common disease on cucumber in around 80 countries and causes severe economic losses. The long-term usage of fungicide also leads to the occurrence of fungicide resistance and decreases host resistance. In this study, six types of oil (neem oil, moringa oil, soybean oil, cinnamon oil, clove oil, and camellia oil) were selected to synthesize micro/nano-sized emulsions, and the disease control efficacy of micro/nano-sized emulsions were evaluated. Moreover, oil concentrations (0.125% - 1%) and droplet size of emulsion were studied. Results showed cinnamon-type emulsion had the best efficacy among these oils. The disease control efficacy of these emulsions increased as the oil concentration increased. Both disease incidence and disease severity were measured by detached leaf and pot experiment, respectively. For the droplet size effect, results showed that the 114 nm of droplet size synthesized by 0.25% cinnamon oil emulsion had the lowest disease incidence (6.67%) and lowest disease severity (33.33%). The release of zoospore was inhibited (5.33%), and the sporangia germination was damaged. These results suggest that cinnamon oil emulsion will be a valuable and environmentally friendly alternative to control cucumber downy mildew. The economic loss caused by plant disease could also be reduced.

Keywords: downy mildew, emulsion, oil droplet size, plant protectant

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Authors: Young-Cheol Choi, Joo-Hyung Kim, Gyu-Don Moon

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This paper discusses the effect of Na2O (alkali) content, SiO2/Na2O mole ratio, and elevated temperature on the mechanical performance of fly-ash-based inorganic green geopolymer composites. Fly-ash-based geopolymers, which were manufactured with varying alkali contents (4–8 % of fly ash weight) and SiO2/Na2O mole ratios (0.6–1.4), were subjected to elevated temperatures up to 900 ºC ; the geopolymer composites and their performance were evaluated on the basis of weight loss and strength loss after temperature exposure. In addition, mineralogical changes due to the elevated temperature exposure were studied using x-ray diffraction. Investigations of microstructures and microprobe analysis were performed using mercury intrusion porosimetry. The results showed that the fly-ash-based geopolymer responded significantly to high-temperature conditions.

Keywords: fly ash, geopolymer, micro-structure, high-temperature, mechanical structural

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Authors: P. Haldar, P. Ghosh, S. Ghoshdastidar, K. Kargupta

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In polymer electrolyte membrane fuel cells (PEMFC), the membrane electrode assembly (MEA) is consisting of two platinum coated carbon electrodes, sandwiched with one proton conducting phosphoric acid doped polymeric membrane. Due to low mechanical stability, flooding and fuel cell crossover, application of phosphoric acid in polymeric membrane is very critical. Phosphorous and silica based 3D inorganic gel gains the attention in the field of supercapacitors, fuel cells and metal hydrate batteries due to its thermally stable highly proton conductive behavior. Also as a large amount of water molecule and phosphoric acid can easily get trapped in Si-O-Si network cavities, it causes a prevention in the leaching out. In this study, we have performed molecular dynamics (MD) simulation and first principle calculations to understand the structural, electronics and electrochemical and morphological behavior of this inorganic gel at various P to Si ratios. We have used dipole-dipole interactions, H bonding, and van der Waals forces to study the main interactions between the molecules. A 'structure property-performance' mapping is initiated to determine optimum P to Si ratio for best proton conductivity. We have performed the MD simulations at various temperature to understand the temperature dependency on proton conductivity. The observed results will propose a model which fits well with experimental data and other literature values. We have also studied the mechanism behind proton conductivity. And finally we have proposed a structure for the gel paste with optimum P to Si ratio.

Keywords: first principle calculation, molecular dynamics simulation, phosphorous and silica based 3D inorganic gel, polymer electrolyte membrane fuel cells, proton conductivity

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Authors: Habib Ur Rahman Habib

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Renewable energy resources are being realized as suitable options in hybrid energy planning for on-grid and micro grid. In this paper, operation, planning and optimal design of on-grid distributed energy resources based hybrid system are investigated. The aim is to minimize the cost of the overall energy system keeping in view the environmental emission and minimum penetration of conventional energy resources. Seven grid connected different case studies including diesel only, diesel-renewable based, and renewable based only are designed to perform economic analysis, operational planning and emission. Sensitivity analysis is implemented to investigate the impact of different parameters on the performance of energy resources.

Keywords: data management, renewable energy, distributed energy, smart grid, micro-grid, modeling, energy planning, design optimization

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Authors: Subir Gupta, Subhas Ganguly

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In this paper, we demonstrate the new area of application of image processing in metallurgical images to develop the more opportunity for structure-property correlation based approaches of alloy design. The present exercise focuses on the development of image processing tools suitable for phrase segmentation, grain boundary detection and recognition of micro-constituents in SEM micrographs of ferrite and pearlite steels. A comprehensive data of micrographs have been experimentally developed encompassing the variation of ferrite and pearlite volume fractions and taking images at different magnification (500X, 1000X, 15000X, 2000X, 3000X and 5000X) under scanning electron microscope. The variation in the volume fraction has been achieved using four different plain carbon steel containing 0.1, 0.22, 0.35 and 0.48 wt% C heat treated under annealing and normalizing treatments. The obtained data pool of micrographs arbitrarily divided into two parts to developing training and testing sets of micrographs. The statistical recognition features for ferrite and pearlite constituents have been developed by learning from training set of micrographs. The obtained features for microstructure pattern recognition are applied to test set of micrographs. The analysis of the result shows that the developed strategy can successfully detect the micro constitutes across the wide range of magnification and variation of volume fractions of the constituents in the structure with an accuracy of about +/- 5%.

Keywords: SEM micrograph, metallurgical image processing, ferrite pearlite steel, microstructure

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Authors: Gonzalo Ortiz de Elguea-Culebras, Raúl Sánchez-Vioquea, Adela Mena-Morales, Manuel Alaiz, Enrique Melero-Bravo, Esteban García-Romero, Javier Vioque, Lourdes Marchante-Cuevas, Julio Girón-Calle

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Saffron (Crocus sativus L.) is a highly valued crop for the manufacture of spice that consists of the dried stigma of the flowers. This is in contrast to other underutilized parts of the saffron plant as leaves, which represent abundant biomass whose use might help to enhance the sustainability of the saffron crop. Saffron leaves contain significant amounts of phenolic compounds, 7.8 equivalent grams of gallic acid per 100g of extract, and are very promising compounds in terms of exploring novel uses of saffron leaves. Given that phenolic compounds have numerous effects on cancer-related biological pathways, we have investigated the in vitro antiproliferative effect of saffron leaf polyphenols against human colon adenocarcinoma cells (Caco-2). Polyphenols were extracted from leaves with 70% ethanol, defatted with hexane, and purified by solid phase extraction using C18 silica gel and then silica gel 60. Analysis of polyphenols was performed by HPLC-ESI-MS. Di-, tri-, and tetrahexosides of quercetin, kaempferol, and isorhamnetin, as well as C-hexosides like isoorientin and vitexin, were tentatively identified. Polyphenols strongly inhibited the proliferation of Caco-2 cells, which is consistent with model studies in which several of the polyphenols identified in saffron leaves have demonstrated their potential as chemopreventive agents in cancer. Due to the low profitability that saffron leaf currently represents, we consider these results very encouraging and that this by-product deserves further investigation as a potential source of active molecules against colorectal cancer.

Keywords: saffron leaves, agricultural by-products, polyphenols, antiproliferative effect, human colon adenocarcinoma cells

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Authors: Abongile Zweni, Grate Moyo, Ricardo Peters, Bingwen Yan

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Budgets are one of the most important tools that organisations, big or small, need to use as management tools. When organisations, particularly Small, Medium and Micro Enterprises (SMMEs), do not use budgets, they are bound to fail in their infancy stage. The aim of this study was to assess whether or not SMMEs in South Africa used budgets as an effective management tool during the COVID-19 pandemic. For the purposes of this study, data was collected using an online questionnaire (survey). This study used the quantitative research approach. The study used descriptive statistics to analyse the research question. The study found that most SMMEs did not use budgets during the COVID-19 pandemic; one of the reasons, amongst others, was that most of them had to close down during the lockdown, and some of them did not even qualify for government bailout or government grants.

Keywords: budget management, SMMEs, COVID-19, South Africa

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Authors: I. Slim, H. Akkari, A. Ben Abdallah, I. Bhouri, M. Hedi Bedoui

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Osteoporosis is a common disease characterized by low bone mass and deterioration of micro-architectural bone tissue, which provokes an increased risk of fracture. This work treats the texture characterization of trabecular bone radiographs. The aim was to analyze according to clinical research a group of 174 subjects: 87 osteoporotic patients (OP) with various bone fracture types and 87 control cases (CC). To characterize osteoporosis, Fractal and MultiFractal (MF) methods were applied to images for features (attributes) extraction. In order to improve the results, a new method of MF spectrum based on the q-stucture function calculation was proposed and a combination of Fractal and MF attributes was used. The Support Vector Machines (SVM) was applied as a classifier to distinguish between OP patients and CC subjects. The features fusion (fractal and MF) allowed a good discrimination between the two groups with an accuracy rate of 96.22%.

Keywords: fractal, micro-architecture analysis, multifractal, osteoporosis, SVM

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Authors: Yong-Hui Zheng

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Viruses hijack host machineries to propagate and spread, which disrupts cellular homeostasis and activates various counteractive mechanisms. Infection of enveloped viruses is dependent on their fusion proteins, which bind to viral receptors to allow virus entry into cells. Fusion proteins are glycoproteins and expressed in the endoplasmic reticulum (ER) by hijacking the secretory pathway. Previously, we reported that Zaire ebolavirus (EBOV)-glycoprotein (GP) expression induces ER stress, and EBOV-GP is targeted by the calnexin cycle to macro-ER-phagy for degradation. We now report that expression of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2/SARS2)-spike (S) protein also causes ER stress, and its expression is strongly downregulated by mannosidase alpha class 1B member 1 (MAN1B1), a class I α-mannosidase from the ER. MAN1B1 co-localizes with SARS2-S in the ER, and its downregulation of SARS2-S is blocked by inhibitors targeting lysosomes and autophagy, but not proteasomes, indicating SARS2-S degradation by autolysosomes. Notably, the SARS2-S degradation does not require the core autophagy machinery including ATG3, ATG5, ATG7, and phosphatidylinositol 3-kinase catalytic subunit type 3 (PI3KC3)/vacuolar protein sorting 34 (VPS34), and instead, it requires Beclin 1 (BECN1), a core component in the PI3KC3 complex. In addition, MAN1B1 does not trigger SARS2-S polyubiquitination, and consistently, the SARS2-S degradation does not require the autophagy receptor sequestosome 1 (SQSTM1)/p62. MAN1B1 also downregulates EBOV-GP similarly, but this degradation does not require BECN1. Collectively, we conclude that MAN1B1 downregulates viral fusions by micro-ER-phagy, and importantly, we have identified BECN1-dependent and BECN1-independent mechanisms for micro-ER-phagy.

Keywords: Micro-ER-phagy, reticulophagy, fusion proteins, ER stress

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Authors: Matej Patzelt, Jana Mrzilkova, Jan Dudak, Frantisek Krejci, Jan Zemlicka, Zdenek Wurst, Petr Zach, Vladimir Musil

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Introduction: Micro-CT is well used for examination of bone structures and teeth. On the other hand visualization of the soft tissues is still limited. The goal of our study was to elaborate methodology for soft tissue samples imaging in micro-CT. Methodology: We used organs of rats and mice. We either did a preparation of the organs and fixation in contrast solution or we did cannulation of blood vessels and their injection for imaging of the vascular system. First, we scanned native specimens, then we created corrosive specimens by resins. In the next step, we injected vascular system either by Aurovist contrast agent or by Exitron. In the next step, we focused on soft tissues contrast increase. We scanned samples fixated in Lugol solution, samples fixated in pure ethanol and in formaldehyde solution. All used methods were afterwards compared. Results: Native specimens did not provide sufficient contrast of the tissues in any of organs. Corrosive samples of the blood stream provided great contrast and details; on the other hand, it was necessary to destroy the organ. Further examined possibility was injection of the AuroVist contrast that leads to the great bloodstream contrast. Injection of Exitron contrast agent comparing to Aurovist did not provide such a great contrast. The soft tissues (kidney, heart, lungs, brain, and liver) were best visualized after fixation in ethanol. This type of fixation showed best results in all studied tissues. Lugol solution had great results in muscle tissue. Fixation by formaldehyde solution showed similar quality of contrast in the tissues like ethanol. Conclusion: Before imaging, we need to, first, determinate which structures of the soft tissues we want to visualize. In the case of the bloodstream, the best was AuroVist and corrosive specimens. Muscle tissue is best visualized by Lugol solution. In the case of the organs containing cavities, like kidneys or brain, the best way was ethanol fixation.

Keywords: experimental imaging, fixation, micro-CT, soft tissues

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Authors: Arvind Mittal, Rajesh Gupta

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Influence of heat input on the micro structure and mechanical properties of shield metal arc welded of duplex stainless steel UNSNO.S-31803 has been investigated. Three heat input combinations designated as low heat (0.675 KJ/mm), medium heat (0.860 KJ/mm) and high heat (1.094 KJ/mm) and weld joints made using these combinations were subjected to micro structural evaluations and tensile and impact testing so as to analyze the effect of thermal arc energy on the micro structure and mechanical properties of these joints. The result of this investigation shows that the joints made using low heat input exhibited higher tensile strength than those welded with medium and high heat input. Heat affected zone of welded joint made with medium heat input has austenitic ferritic grain structure with some patchy austenite provide high toughness. Significant grain coarsening was observed in the heat affected zone (HAZ) of medium and high heat input welded joints, whereas low heat input welded joint shows the fine grain structure in the heat affected zone with small amount of dendritic formation and equiaxed grain structure where inner zone indicates slowly cooled grains in the direction of heat dissipation. This is the main reason for the observable changes of tensile properties of weld joints welded with different arc energy inputs.

Keywords: microstructure, mechanical properties, shield metal arc welded, duplex stainless steel

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Authors: Muhammad Sufyan, Muhammad J. Arif, Muhammad Arshad, Usman Shoukat

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In Pakistan, wheat (Triticum aestivum L.) is seriously attacked by the wheat ‎aphid. Naturally, bio control agents play an important role in managing wheat aphid. However, association ‎among pest, natural enemies and host plant is highly affected by food resource ‎concentration and predator/parasitoid factor of any ecosystem. The present ‎study was conducted to estimate the effect of different dose levels of macro ‎and micronutrients on the aphid population and its entomophagous insect ‎on wheat and their tri-trophic association. The experiment was laid out in ‎RCBD with six different combinations of macro and micronutrients and a control treatment. The data was initiated from the second week of ‎the February till the maturity of the crop. Data regarding aphid population and ‎coccinellids counts were collected on weekly basis and subjected to analysis of ‎variance and mean comparison. The data revealed that aphid ‎population was at peak in the last week of March. Coccinellids population ‎increased side by side with aphid population and declined after second week of ‎April. Aphid parasitism was maximum 25% on recommended dose of Double and ‎Flasher and minimum 8.67% on control treatment. Maximum aphid population was observed on first April with 687.2 specimens. However, this maximum population was shown against the application of Double + Flasher treatment. The minimum aphid population was recorded after the application of HiK Gold + Flasher recommended dose on 15th April. The coccinellids population was at peak level at on 8th April and against the treatment double recommended dose of HiK gold + Flasher. Amount of nitrogen, phosphorus and potassium percentage dry leaves ‎components was maximum (2.33, 0.18 and 2.62 % dry leaves. respectively) in ‎plots treated with recommended double dose mixture of Double + Flasher and ‎Hi-K Gold + Flasher while it was minimum (1.43, 0.12 and 1.77 dry leaves ‎respectively) in plots where no nutrients applied. The result revealed that maximum parasitism was at recommended level of micro and macro nutrients application.‎ Maximum micro nutrients zinc, copper, manganese, iron and boron found with values 46.67 ppm, 21.81 ppm, 62.35 ppm, 152.69 ppm and 36.78 respectively. The result also showed that Over application of macro and micro nutrients should be avoided because it do not help in pest control, conversely it may cause stress on plant. The treatment Double and Flasher recommended dose ratio is almost comparable with recommended dose and present studies confirm its usefulness on wheat.

Keywords: entomophagous insects, macro and micro nutrients, tri-trophic, wheat aphid

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Authors: Mohammad Khoshini, Arman Khoshghalb, Meghdad Payan, Nasser Khalili

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Most of the Earth’s crust surface rocks are technically categorized as weak rocks or weakly bonded geomaterials. Deeply weathered, weakly cemented, friable and easily erodible, they demonstrate complex material behaviour and understanding the overlooked mechanical behaviour of such materials is of particular importance in geotechnical engineering practice. Weakly bonded geomaterials are so susceptible to surface shear and moisture that conventional methods of core drilling fail to extract high-quality undisturbed samples out of them. Moreover, most of these geomaterials are of high heterogeneity rendering less reliable and feasible material characterization. In order to compensate for the unpredictability of the material response, either numerous experiments are needed to be conducted or large factors of safety must be implemented in the design process. However, none of these approaches is sustainable. In this study, a method for dry core drilling of such materials is introduced to take high-quality undisturbed core samples. By freezing the material at certain moisture content, a secondary structure is developed throughout the material which helps the whole structure to remain intact during the core drilling process. Moreover, to address the heterogeneity issue, the natural material was reconstructed artificially to obtain a homogeneous material with very high similarity to the natural one in both micro and macro-mechanical perspectives. The method is verified for both micro and macro scale. In terms of micro-scale analysis, using Scanning Electron Microscopy (SEM), pore spaces and inter-particle bonds were investigated and compared between natural and artificial materials. X-Ray Diffraction, XRD, analyses are also performed to control the chemical composition. At the macro scale, several uniaxial compressive strength tests, as well as triaxial tests, were performed to verify the similar mechanical response of the materials. A high level of agreement is observed between micro and macro results of natural and artificially bonded geomaterials. The proposed methods can play an important role to cut down the costs of experimental programs for material characterization and also to promote the accuracy of the numerical modellings based on the experimental results.

Keywords: Artificial geomaterial, core drilling, macro-mechanical behavior, micro-scale, sample preparation, SEM photography, weakly bonded geomaterials

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Authors: Harris Maduku, Irrshad Kaseeram

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The objective of this paper is to understand the factors behind the formalisation willingness of South African black owned SMMEs. Cross-sectional data were collected using a questionnaire from 390 informal businesses in Johannesburg and Pretoria using stratified random sampling and clustered sampling. This study employed a multinomial logistic regression to quantitatively understand what encourages informal SMMEs to be willing to mainstreaming their operations. We find government support, corruption, employment compensation, family labour, success perception, education status, age and financing as key drivers on willingness of SMMEs to formalize their operations. The findings of our study points to government departments to invest more on both financial and non-financial strategies like capacity building and business education on informal SMMEs to cultivate their willingness to mainstream.

Keywords: mainstreaming, transition, informal, willingness, multinomial logit

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Authors: K. A. Mistry, I. B. Patel, A. H. Prajapati

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In the present work, the alloy of Bismuth-lead is prepared on the basis of percentage of molecular weight 9:1, 5:5 and 1:9 ratios and grown by Zone- Refining Technique under a vacuum atmosphere. The EDAX of these samples are done and the results are reported. Micro hardness test has been used as an alternative test for measuring material’s tensile properties. The effect of temperature and load on the hardness of the grown alloy has been studied. Further the comparative studies of work hardening coefficients are reported. In the present work, the alloy of Bismuth-lead is prepared on the basis of percentage of molecular weight 9:1, 5:5 and 1:9 ratios and grown by Zone- Refining Technique under a vacuum atmosphere. The EDAX of these samples are done and the results are reported. Micro hardness test has been used as an alternative test for measuring material’s tensile properties. The effect of temperature and load on the hardness of the grown alloy has been studied. Further the comparative studies of work hardening coefficients are reported.

Keywords: EDAX, hardening coefficient, micro hardness, Bi-Pb alloy

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Authors: Yu Chen, Seong-Jin Kim, Jaehoon Chung

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High throughput cells counting and sizing are often required for biomedical applications. Here we report design, fabrication and validating of a micro-machined Coulter counter device with multiple-channel to realize such application for low cost. Multiple vertical through-holes were fabricated on a silicon chip, combined with the PDMS micro-fluidics channel that serves as the sensing channel. In order to avoid the crosstalk introduced by the electrical connection, instead of measuring the current passing through, the potential of each channel is monitored, thus the high throughput is possible. A peak of the output potential can be captured when the cell/particle is passing through the microhole. The device was validated by counting and sizing the polystyrene beads with diameter of 6 μm, 10 μm and 15 μm. With the sampling frequency to be set at 100 kHz, up to 5000 counts/sec for each channel can be realized. The counting and enumeration of MCF7 cancer cells are also demonstrated.

Keywords: Coulter counter, cell enumeration, high through-put, cell sizing

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Authors: Athul T.

Abstract:

Kerala cities in India are grappling with an alarming rise in temperatures fueled by the Urban Heat Island (UHI) effect. This phenomenon, exacerbated by rapid urbanization and climate change, poses a significant threat to public health and environmental well-being. In response to this growing concern, this study investigates the potential of urban vegetation as a powerful mitigation strategy against UHI. The study delves into the intricate relationship between micro-climate changes, UHI intensity, and the strategic placement of greenery in alleviating these effects. Utilizing advanced simulation software, the most effective vegetation types and configurations for maximizing UHI reduction will be identified. By analyzing the current state of Kozhikode's urban vegetation and its influence on microclimates, this study aims to tailor actionable strategies for Kerala cities, potentially paving the way for a more sustainable and thermally comfortable urban future.

Keywords: urban heat island, climate change, micro climate, urban vegetation

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Authors: E. Gandomkar, S. Sabbaghi

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In this paper, the effects of variation synthesized methods on morphology and size of silica nanostructure via modifying sol-gel and precipitation method have been investigated. Meanwhile, resulting products have been characterized by particle size analyzer, scanning electron microscopy (SEM), X-ray Diffraction (XRD) and Fourier transform infrared (FT-IR) spectra. As result, the shape of SiO2 with sol-gel and precipitation methods was spherical but with modifying sol-gel method we have been had nanolayer structure.

Keywords: modified sol-gel, precipitation, nanolayer, Na2SiO3, nanoparticle

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Authors: Mutwakil Nafi, Abed Elaziz El Amein, Muna El Dawi, Khalafala Salih, Osma Elbahi, Abed Elhalim Abou

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Recently a large deposit of oolitic iron ore of Late Carboniferous-Permotriassic-Lower Jurassic age was discovered in Wadi Halfa and Argein areas, North Sudan. It seems that the iron ore mineralization exists in the west and east bank of the River Nile of the study area that are found on the Egyptian-Sudanese border. The Carboniferous-Lower Jurassic age strata were covered by 67 sections and each section has been examined and carefully described. The iron-ore in Wadi Halfa occurs as oolitic ironstone and contained two horizons: (A) horizon and (B) horizon. Only horizon (A) was observed in southern Argein area. The texture of the ore is variable depending on the volume of the component. In thin sections the average of the ooids were ranged between 90% - 80%. The matrix varies between 10%-20% by volume and detritus quartz in other component my reach up to 30% by volume in sandy massive ore. Ooids size ranges from 0.2mm-1.00 mm on average in very coarse ooids may attend up to 1 mm in size. The matrix around the ooids is dominated by iron hydroxide, carbonate, fine and amorphous silica. The probable ore reserve estimate of 1.234 billion at a head grade of 41.29% Fe for the Wadi Halfa Oolitic Ironstone Formation. The iron ore shows higher content of phosphorus ranges from 6.15% to 0.16%, with mean 1.45%. The new technology Hatch–Ironstone Chloride Segregation (HICS) can be used to produce commercial-quality of iron and reduce phosphorus and silica to acceptable levels for steel industry. The development of infra structures and presence huge quantity of iron ore would make exploitation of the iron ore economic.

Keywords: HICS, Late Carboniferous age, oolitic iron ore, phosphorus

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Authors: Mohamed M. A. Rahoma

Abstract:

A better understanding of the factors that control the resistivity values of Sandstone reservoirs is very important for petroleum exploration and production. This study is an attempt to find out the factors that could be the reason for the decrease in resistivity values of the Lower Akakus Sandstones, which are the main reservoir in the area in an onshore field located in the northern part of Ghadames Basin - Northwest of Libya in the contracted area 47, block 2 The study achieved is based on: 30 core chip samples taken from two wells (A3-47/02 and J1-47/02) and Routine Core Analysis (RCA). The results of petrography analysis (thin section, X-ray diffraction and SEM) demonstrated that the depth sits (intervals) which illustrated low resistivity values have a relatively high content of diagenetic clay and cement minerals, hence we can conclude that diagenetic events have a more significant impact on the resistivity values of studied interval for possibly two following reasons: The first essential reason, the extensive micro pores that mostly exist within clay minerals (Chlorite and Kaolinite where, about 30-50 % of their composition considered micro pores), resistivity log read low as noticed through the study. The highest value of micro pores recorded in core1 of J1-47/02 well due to most likely the kaolinite amount which was a slightly higher than the chlorite amount in this well (the bond water porosity for chlorite clay considered relatively the lowest porosity compared to other clay minerals). The second reason, the presence of diagenetic cement minerals (Siderite and Hematite, which contain an iron element as one of their components) within the studied interval as remarked from my study may cause decreasing in resistivity of the formation of the reservoir.

Keywords: diagenetic cement, diagenetic clay, resistivity, petrography analysis

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Authors: Asamaporn Puetpaiboon, Sunisa Chatmongkolchart, Nalinee Kovitwanawong, Osaree Akaraborworn

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Traumatic patients with massive bleeding require intensive resuscitation. The actual cost of anesthesia per case has never been clarified, so our study aimed to quantify the direct cost, and cost-to-charge ratio of anesthetic care in traumatic patients with intraoperative massive bleeding. This study was a prospective, observational, cost analysis study, conducted in Prince of Songkla University hospital, Thailand, with traumatic patients, of any mechanisms being recruited. Massive bleeding was defined as estimated blood loss of at least one blood volume in 24 hours, or a half of blood volume in 3 hours. The cost components were identified by the micro-costing method, and valued by the bottom-up approach. The direct cost was divided into 4 categories: the labor cost, the capital cost, the material cost and the cost of drugs. From September 2017 to August 2018, 10 patients with multiple injuries were included. Seven patients had motorcycle accidents, two patients fell from a height and another one was in a minibus accident. Two patients died on the operating table, and another two died within 48 hours. The median Sequential Organ Failure Assessment (SOFA) score was 8. The median intraoperative blood loss was 3,500 ml. The median direct cost, per case, was 250 United States Dollars (2017 exchange rate), and the cost-to-charge ratio was 0.53. In summary, the direct cost was nearly half of the hospital charge, for these traumatic patients with massive bleeding. However, our study did not analyze the indirect cost.

Keywords: cost, cost-to-charge ratio, micro-costing, trauma

Procedia PDF Downloads 146

Authors: Milton Manyangadze, Joseph Govha, T. Bala Narsaiah, Ch. Shilpa Chakra

Abstract:

The availability and access to fresh water is today a serious global challenge. This has been a direct result of factors such as the current rapid industrialization and industrial growth, persistent droughts in some parts of the world, especially in the sub-Saharan Africa as well as population growth. Growth of the chemical processing industry has also seen an increase in the levels of pollutants in our water bodies which include heavy metals among others. Heavy metals are known to be dangerous to both human and aquatic life. As such, they have been linked to several diseases. This is mainly because they are highly toxic. They are also known to be bio accumulative and non-biodegradable. Lead for example, has been linked to a number of health problems which include damage of vital internal body systems like the nervous and reproductive system as well as the kidneys. From this background therefore, the removal of the toxic heavy metal, Pb2+ from waste water was investigated using nano silica hollow spheres (NSHS) as the adsorbent. Synthesis of NSHS was done using a three-stage process in which CaCO3 nanoparticles were initially prepared as a template. This was followed by treatment of the formed oxide particles with NaSiO3 to give a nanocomposite. Finally, the template was destroyed using 2.0M HCl to give NSHS. Characterization of the nanoparticles was done using analytical techniques like XRD, SEM, and TGA. For the adsorption process, both thermodynamic and equilibrium studies were carried out. Thermodynamic studies were carried out and the Gibbs free energy, Enthalpy and Entropy of the adsorption process were determined. The results revealed that the adsorption process was both endothermic and spontaneous. Equilibrium studies were also carried out in which the Langmuir and Freundlich isotherms were tested. The results showed that the Langmuir model best described the adsorption equilibrium.

Keywords: characterization, endothermic, equilibrium studies, Freundlich, Langmuir, nanoparticles, thermodynamic studies

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Authors: Mahdi Asghari

Abstract:

The cavitation phenomenon is the formation and production of micro-bubbles and eventually the bursting of the micro-bubbles inside the liquid fluid, which results in localized high pressure and temperature, causing physical and chemical fluid changes. This pressure and temperature are predicted to be 2000 atmospheres and 5000 °C, respectively. As a result of small bubbles bursting from this process, temperature and pressure increase momentarily and locally, so that the intensity and magnitude of these temperatures and pressures provide the energy needed to break the molecular bonds of heavy compounds such as fuel oil. In this paper, we study the theory of cavitation and the methods of cavitation production by acoustic and hydrodynamic methods and the necessary mechanical equipment and reactors for industrial application of the hydrodynamic cavitation method to break down the molecular bonds of the fuel oil and convert it into useful and economical products.

Keywords: Cavitation, Hydrodynamic Cavitation, Cavitation Reactor, Fuel Oil

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