Search results for: mean free path

Authors: Wei-Shan Wang, Klaus Vogel, Felix Gabler, Maik Wiemer, Thomas Gessner

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Metallic glasses, which are free of grain boundaries, have superior properties including large elastic limits, high strength, and excellent wear and corrosion resistance. Therefore, bulk metallic glasses (BMG) and thin film metallic glasses (TFMG) have been widely developed and investigated. Among various kinds of metallic glasses, Pd-Cu-Si TFMG, which has lower elastic modulus and better resistance of oxidation and corrosions compared to Zr- and Fe-based TFMGs, can be a promising candidate for MEMS applications. However, the study of Pd-TFMG membrane is still limited. This paper presents free-standing Pd-based metallic glass membranes with large area fabricated on wafer level for the first time. Properties of Pd-Cu-Si thin film metallic glass (TFMG) with various deposition parameters are investigated first. When deposited at 25°C, compressive stress occurs in the Pd76Cu6Si18 thin film regardless of Ar pressure. When substrate temperature is increased to 275°C, the stress state changes from compressive to tensile. Thin film stresses are slightly decreased when Ar pressure is higher. To show the influence of temperature on Pd-TFMGs, thin films without and with post annealing below (275°C) and within (370°C) supercooled liquid region are investigated. Results of XRD and TEM analysis indicate that Pd-TFMGs remain amorphous structure with well-controlled parameters. After verification of amorphous structure of the Pd-TFMGs, free-standing Pd-Cu-Si membranes were fabricated by depositing Pd-Cu-Si thin films directly on 200nm-thick silicon nitride membranes, followed by post annealing and dry etching of silicon nitride layer. Post annealing before SiNx removal is used to further release internal stress of Pd-TFMGs. The edge length of the square membrane ranges from 5 to 8mm. The effect of post annealing on Pd-Cu-Si membranes are discussed as well. With annealing at 370°C for 5 min, Pd-MG membranes are fully distortion-free after removal of SiNx layer. Results show that, by introducing annealing process, the stress-relief, distortion-free Pd-TFMG membranes with large area can be a promising candidate for sensing applications such as pressure and gas sensors.

Keywords: amorphous alloy, annealing, metallic glasses, TFMG membrane

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Authors: Rabson Banda

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This abstract delves into the transformative journey of Rabson Banda, a visionary leader in Zambia who has harnessed the power of photovoice, mental fitness, and entrepreneurship to combat substance use disorders in the face of limited job opportunities in Africa. Rabson's personal battle with alcohol-induced disorder serves as the foundation for his pioneering work in establishing Elevated Initiatives, a grassroots organization dedicated to empowering individuals struggling with addiction through innovative approaches. Through the lens of photovoice, Rabson Banda amplifies the voices of those affected by substance abuse, providing a platform for self-expression and healing. By intertwining mental fitness techniques and entrepreneurial skills, he equips individuals with the tools needed to break free from the cycle of addiction and chart a new path toward holistic wellness and economic independence. Rabson Banda's story embodies resilience, hope, and the unwavering belief in the transformative power of community-driven initiatives. His work not only addresses the immediate challenges of substance use disorders but also addresses the root causes of addiction by advocating for increased job opportunities and economic empowerment in Zambia and across Africa for decent job creation and Entrepreneurship: A Lived Experience of Alcohol-Induced Disorder and Recovery in Zambia.

Keywords: mental fitness, entrepreneurship, photovoice, descent jobs

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Authors: Eneken Titov, Ly Hobe

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The collaboration between the universities and companies has been a challenging topic for many years, and although we have many good experiences, those seem to be single examples between one university and company. In Ülemiste Smart City in Estonia, the new initiative was started in 2020 fall, when five Estonian universities cooperated, led by the Ülemiste City developing company Mainor, intending to provide charge-free university courses for the Ülemiste City companies and their employees to encourage university-company wider collaboration. Every Ülemiste City company gets a certain number of free educational credit hours per year to participate in university courses. A functional and simple web platform was developed to mediate university courses for the companies. From January 2021, the education credit platform is open for all Ülemiste City companies and their employees to join, and universities offer more than 9000 hours of courses (appr 150 ECTS). Just two months later, more than 20% of Ülemiste City companies (82 out of 400) have joined the project, and their employees have registered for more than in total 3000 hours courses. The first results already show that the project supports the university marketing and the continuous education mindset in general, whether 1/4 of the courses are paid courses (e.g., when the company is out of free credit).

Keywords: education, educational credit, smart city, university-industry collaboration

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Authors: Radhapiyari Laishram, Chongtham Jiten, K. Chandramani Singh

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During the last decade, there has been a significant growth in developing lead-free piezoelectric ceramics which have the potential to replace the currently dominant but highly superior lead-based piezoelectric materials such as PZT. Among the lead-free piezoelectrics, (K0.5Na0.5)NbO3 - based piezoceramics are promising candidates due to their superior piezoelectric properties and high Curie temperatures. In this work, (K0.5Na0.5)(Nb1-xVx)O3 powders with x varying the range 0 to 0.05 were synthesized from the raw materials K2CO3, Na2CO3, Nb2O5, and V2O5. These powders were ball milled with high-energy Retsch PM 100 ball mill using isopropanol as the medium at the speed of 200rpm for a duration of 8h. The milled powders were sintered at 1080oC for 1h. The crystalline phase of all the calcined powders and corresponding ceramics prepared was found to be perovskite with orthorhombic symmetry. The ceramic with V5+ content of x=0.03 exhibits the maximum values in density of 4.292 g/cc, room temperature dielectric constant (εr) of 432, and piezoelectric charge constant (d33) of 93pC/N. For this sample, the dielectric tan δ loss remains relatively low over a wide temperature range. The temperature dependence of P-E hysteresis loops has been investigated for the ceramic composition with x = 0.03.

Keywords: dielectric properties, ferroelectric properties, perovskie, piezoelectric properties

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Authors: Ashagrie Getnet Flattie

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Line-of-sight (LOS) information, data rates, good quality, and flexible network service are limited by the fact that, for the duration of any given connection, they experience severe variation in signal strength due to fading and path loss. Wireless system faces major challenges in achieving wide coverage and capacity without affecting the system performance and to access data everywhere, all the time. In this paper, the cell coverage and edge rate of different Multiple-input multiple-output (MIMO) schemes in 20 MHz Long Term Evolution (LTE) system under Unmanned Air Vehicles (UAV) platform are investigated. After some background on the enormous potential of UAV, MIMO, and LTE in wireless links, the paper highlights the presented system model which attempts to realize the various benefits of MIMO being incorporated into UAV platform. The performances of the three MIMO LTE schemes are compared with the performance of 4x4 MIMO LTE in UAV scheme carried out to evaluate the improvement in cell radius, BER, and data throughput of the system in different morphology. The results show that significant performance gains such as bit error rate (BER), data rate, and coverage can be achieved by using the presented scenario.

Keywords: LTE, MIMO, path loss, UAV

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Authors: E. O. Echeweozo

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This study evaluated radiation shielding and interaction characteristics of polyvinyl alcohol (PVA) polymer separately doped with 10% and 20% nanoscale Bi₂O₃, respectively, for medical apron design and shielding special electronic installations. Prepared samples were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The EDS results showed that Carbon (C), Oxygen (O), and bismuth (Bi) elements were the predominant elements present in the prepared samples. The SEM result displaced surface irregularities due to a special bonding matrix between PVA and Bi₂O₃. Mass attenuation coefficient (MAC), effective atomic number (Zeff), Half value layer (HVL), Mean free path (MFP), Fast neutron removal cross-section (R), Total Mass Stopping Power (TSP), and photon Range (R) of the prepared polymer composites (PV-1Bi and PV-2Bi) were evaluated with XCOM and PHITS computer programs. Results showed that the MAC of the prepared polymer samples was significantly higher than some recently developed composites at 0.662MeV and 1.25MeV gamma energy. Therefore, polyvinyl alcohol (PVA) polymer doped with Bi₂O₃ should be deployed in medical apron design and shielding special electronic installations where flexibility and high adhesion ability are crucial.

Keywords: polyvinyl alcohol (PVA);, polymer composite, gamma-rays, charged particles

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Authors: M. Abdullah Al Faruque, Rechana Remadevi, Abu Naser M. Ahsanul Haque, Joselito Razal, Xungai Wang, Maryam Naebe

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Generally, the colouration of textile fibres is performed by using synthetic colourants in dope dyeing or conventional dyeing methods. However, the toxic effect of some synthetic colorants due to long-term exposure can cause several health threats including cancer, asthma and skin diseases. Moreover, in colouration process, these colourants not only consume a massive amount of water but also generates huge proportion of wastewater to the environment. Despite having the environmentally friendly characteristics, current natural colourants have downsides in their yield and need chemical extraction processes which are water consuming as well. In view of this, the present work focuses to develop a chemical-free biocompatible and natural pigment based colouration technique to colour regenerated fibres. Waste alpaca fibre was used as a colourant and the colour properties, as well as the mechanical properties, of the regenerated fibres were investigated. The colourant from waste alpaca was fabricated through mechanical milling process and it was directly applied to the polyacrylonitrile (PAN) dope solution in different ratios of alpaca: PAN (10:90, 20:80, 30:70). The results obtained from the chemical structure characterization suggested that all the coloured regenerated fibres exhibited chemical functional groups of both PAN and alpaca. Furthermore, the color strength was increased gradually with the increment of alpaca content and showed excellent washing fastness properties. These results reveal a potential new pathway for chemical-free dyeing technique for fibres with improved properties.

Keywords: alpaca, chemical-free coloration, natural colorant, polyacrylonitrile, water consumption, wet spinning

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Authors: John Hardy

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A range of future-oriented intelligence techniques is commonly used by states to assess their national security and develop strategies to detect and manage threats, to develop and sustain capabilities, and to recover from attacks and disasters. Although homeland security organizations use future's intelligence tools to generate scenarios and simulations which inform their planning, there have been relatively few studies of the methods available or their applications for homeland security purposes. This study presents an assessment of one category of strategic intelligence techniques, termed Multi-Path Futures Analyses (MPFA), and how it can be applied to three distinct tasks for the purpose of analyzing homeland security issues. Within this study, MPFA are categorized as a suite of analytic techniques which can include effects-based operations principles, general morphological analysis, multi-path mapping, and multi-criteria decision analysis techniques. These techniques generate multiple pathways to potential futures and thereby generate insight into the relative influence of individual drivers of change, the desirability of particular combinations of pathways, and the kinds of capabilities which may be required to influence or mitigate certain outcomes. The study assessed eighteen uses of MPFA for homeland security purposes and found that there are five key applications of MPFA which add significant value to analysis. The first application is generating measures of success and associated progress indicators for strategic planning. The second application is identifying homeland security vulnerabilities and relationships between individual drivers of vulnerability which may amplify or dampen their effects. The third application is selecting appropriate resources and methods of action to influence individual drivers. The fourth application is prioritizing and optimizing path selection preferences and decisions. The fifth application is informing capability development and procurement decisions to build and sustain homeland security organizations. Each of these applications provides a unique perspective of a homeland security issue by comparing a range of potential future outcomes at a set number of intervals and by contrasting the relative resource requirements, opportunity costs, and effectiveness measures of alternative courses of action. These findings indicate that MPFA enhances analysts’ ability to generate tangible measures of success, identify vulnerabilities, select effective courses of action, prioritize future pathway preferences, and contribute to ongoing capability development in homeland security assessments.

Keywords: homeland security, intelligence, national security, operational design, strategic intelligence, strategic planning

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Authors: Debananda Mohapatra, Subramanya Badrayyana, Smrutiranjan Parida

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Recognizing the upcoming era of carbon nanostructures and their revolutionary applications, we investigated the formation and supercapacitor application of highly pure and hydrophilic carbon nano-onions (CNOs) by economical one-step flame-synthesis procedure. The facile and scalable method uses easily available organic carbon source such as clarified butter, restricting the use of any catalyst, sophisticated instrumentation, high vacuum and post processing purification procedure. The active material was conformally coated onto a locally available cotton wipe by “sonicating and drying” process to obtain novel, lightweight, inexpensive, flexible, binder-free electrodes with strong adhesion between nanoparticles and porous wipe. This interesting electrode with CNO as the active material delivers a specific capacitance of 102.16 F/g, the energy density of 14.18 Wh/kg and power density of 2448 W/kg which are the highest values reported so far in symmetrical two electrode cell configuration with 1M Na2SO4 as an electrolyte. Incorporation of CuO nanoparticles to these functionalized CNOs by one-step hydrothermal method add up to a significant specific capacitance of 420 F/g with deliverable energy and power density at 58.33 Wh/kg and 4228 W/kg, respectively. The free standing CNOs, as well as CNO-CuO composite electrode, showed an excellent cyclic performance and stability retaining 95 and 90% initial capacitance even after 5000 charge-discharge cycles at a current density of 5 A/g. This work presents a new platform for high performance supercapacitors for next generation wearable electronic devices.

Keywords: binder-free, flame synthesis, flexible, carbon nano-onion

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Authors: Hung-Yi Chen, Shih-Jye Wu

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The existing literature provides little discussion on why a public monopolist gives up its market dominant position and allows private firms entering the market. We argue that the privatization of a public monopolist under a vertically related market may induce the entry of private firms. We develop a model of a mixed oligopoly with vertically related markets to explain the change in the market from a public monopolist to a mixed oligopoly and examine issues on privatizing the downstream public enterprise both in the short run and long run in the vertically related markets. We first show that the welfare-maximizing public monopoly firm is suboptimal in the vertically related markets. This is due to the fact that the privatization will reduce the input price charged by the upstream foreign monopolist. Further, the privatization will induce the entry of private firms since input price will decrease after privatization. Third, we demonstrate that the complete privatizing the public firm becomes a possible solution if the entry cost of private firm is low. Finally, we indicate that the public firm should partially privatize if the free-entry of private firms is allowed. JEL classification: F12, F14, L32, L33

Keywords: free entry, mixed oligopoly, public monopoly, the initiation of privatization, vertically related markets, mixed oligopoly

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Authors: Amanbek Jainakov, Abdikerim Kurbanaliev

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The work presents the results of mathematical modeling of large-scale flows in areas with a complex topographic relief. The Reynolds-averaged Navier—Stokes equations constitute the basis of the three-dimensional unsteady modeling. The well-known Volume of Fluid method implemented in the solver interFoam of the open package OpenFOAM 2.3 is used to track the free-boundary location. The mathematical model adequacy is checked by comparing with experimental data. The efficiency of the applied technology is illustrated by the example of modeling the breakthrough of the dams of the Andijan (Uzbekistan) and Papan (near the Osh town, Kyrgyzstan) reservoir.

Keywords: three-dimensional modeling, free boundary, the volume-of-fluid method, dam break, flood, OpenFOAM

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Authors: Michael McCann

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Managerial theories propose that, in joint stock companies, executives may be tempted to waste excess free cash on unprofitable projects to keep control of resources. In order to conceal their projects' poor performance, they may seek to engage in earnings management. On the one hand, managers may manipulate earnings upwards in order to post ‘good’ performances and safeguard their position. On the other, since managers pursuit of unrewarding investments are likely to lead to low long-term profitability, managers will use negative accruals to reduce current year’s earnings, smoothing earnings over time in order to conceal the negative effects. Agency models argue that boards of directors are delegated by shareholders to ensure that companies are governed properly. Part of that responsibility is ensuring the reliability of financial information. Analyses of the impact of board characteristics, particularly board independence on the misuse of free cash flow and earnings management finds conflicting evidence. However, existing characterizations of board independence do not account for such directors gaining firm-specific knowledge over time, influencing their monitoring ability. Further, there is little analysis of the influence of the relative experience of independent directors and executives on decisions surrounding the use of free cash. This paper contributes to this literature regarding the heterogeneous characteristics of boards by investigating the influence of independent director tenure on earnings management and the relative tenures of independent directors and Chief Executives. A balanced panel dataset comprising 51 companies across 11 annual periods from 2005 to 2015 is used for the analysis. In each annual period, firms were classified as conducting earnings management if they had discretionary accruals in the bottom quartile (downwards) and top quartile (upwards) of the distributed values for the sample. Logistical regressions were conducted to determine the marginal impact of independent board tenure and a number of control variables on the probability of conducting earnings management. The findings indicate that both absolute and relative measures of board independence and experience do not have a significant impact on the likelihood of earnings management. It is the level of free cash flow which is the major influence on the probability of earnings management. Higher free cash flow increases the probability of earnings management significantly. The research also investigates whether board monitoring of earnings management is contingent on the level of free cash flow. However, the results suggest that board monitoring is not amplified when free cash flow is higher. This suggests that the extent of earnings management in companies is determined by a range of company, industry and situation-specific factors.

Keywords: corporate governance, boards of directors, agency theory, earnings management

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Authors: Aliya Sekenova, Vyacheslav Ogay

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The derivation of human induced pluripotent stem cells (iPSCs) from somatic cells by direct reprogramming opens wide perspectives in the regenerative medicine. It means the possibility to develop the personal and, consequently, any immunologically compatible cells for applications in cell-based therapy. The purpose of our study was to develop the technology for the production of NK cells from T cell-derived induced pluripotent stem cells (TiPSCs) for subsequent application in adoptive cancer immunotherapy. Methods: In this study iPSCs were derived from peripheral blood T cells using Sendai virus vectors expressing Oct4, Sox2, Klf4 and c-Myc. Pluripotent characteristics of TiPSCs were examined and confirmed with alkaline phosphatase staining, immunocytochemistry and RT-PCR analysis. For NK cell differentiation, embryoid bodies (EB) formed from (TiPSCs) were cultured in xenogeneic serum-free medium containing human serum, IL-3, IL-7, IL-15, SCF, FLT3L without using M210-B4 and AFT-024 stromal feeder cells. After differentiation, NK cells were characterized with immunofluorescence analysis, flow cytometry and cytotoxicity assay. Results: Here, we for the first time demonstrate that TiPSCs can effectively differentiate into functionally active NK cells without M210-B4 and AFT-024 xenogeneic stroma cells. Immunofluorescence and flow cytometry analysis showed that EB-derived cells can differentiate into a homogeneous population of NK cell expressing high levels of CD56, CD45 and CD16 specific markers. Moreover, these cells significantly express killing activation receptors such as NKp44 and NKp46. In the comparative analysis, we observed that NK cells derived using feeder-free culture system have more high killing activity against K-562 tumor cells, than NK cells derived by feeder-dependent method. Thus, we think that our obtained data will be useful for the development of large-scale production of NK cells for translation into cancer immunotherapy.

Keywords: induced pluripotent stem cells, NK cells, T cells, cell diffentiation, feeder cell-free culture system

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Authors: Saleh Kasiri Bidhendi, Shiva Tashakori

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With the increasing application of six-wheel robots in various industries, including agriculture and environmental monitoring, there is a growing demand for efficient and reliable control systems that can improve manoeuvrability and at the same time reduce energy consumption. Moving on uneven terrains, various factors such as obstacles or soil heterogeneity can cause the robot to slip. There is limited research addressing this issue. Although the robot is supposed to track a predetermined path, sudden lateral deviation necessitates path planning. To further address this issue, explicit steering is added by activating actuators on steerable wheels, while the SMC controller still commands differential traction forces on all wheels. This integration improves energy efficiency and obstacle traversability while maintaining the merits of skid-steering, such as tight turning manoeuvrability. However, achieving the desired steer angles presents certain challenges. Inverse kinematics was initially employed to achieve the needed steering angles from the desired position, but this approach led to excessive steering without yawing the body. Switching to desired velocity values instead of position limited over-steering but caused zero lateral velocity on horizontal paths, which was problematic for unforeseen skidding. To overcome this, a proportional controller has been employed, using lateral error as its input and providing a proportional yaw angle as output, the P-controller contributes to modifying the steering angles. The controller's robustness has been verified through sensitivity analyses under critical speeds and turning radius conditions. Our findings offer valuable insights into designing more efficient steering controls for rocker-bogie mechanisms in challenging situations, emphasizing the importance of reducing energy¬ consumption.

Keywords: six-wheel robots, inverse kinematics, integrated steering, path following, manoeuvrability, energy efficiency, uneven terrains

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Authors: Emmanuel O Ajani, Sabiu S, Mariam Zakari, Fisayo A Bamisaye

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Hydrocotyl bonariensis is a plant which anticataractogenic potentials have been reported. In the present study an attempt was made to evaluate the in vitro antioxidant activity of the fractionates of the leaves extract and also characterize some of its chemical constituents. DPPH, H₂O₂, OH and NO free radical scavenging, metal chelating and reducing power activity was used to evaluate the antioxidant activity of the crude extract fractionates. Fresh leaves of Hydrocotyl bonariensis leaves were extracted in 70% methanol. The extract was partitioned with different solvent system of increasing polarity (n-hexane, chloroform, ethyl acetate methanol and water). Compounds were isolated from the aqueous practitionate using accelerated gradient chromatography, vacuum liquid chromatography, preparative TLC and conventional column chromatography. The presence of the chemical groups was established with HPLC and Fourier Transform Infra Red. The structures of isolated compounds were elucidated by spectroscopic study and chemical shifts. Data from the study indicates that all the fractionates contain compounds with free radical scavenging activity. This activity was more pronounced in the aqueous fractionate (DPPH IC₅₀, 0025 ± 0.011 mg/ml, metal chelating capacity 27.5%, OH- scavenging IC₅₀, 0.846 ± 0.037 mg/ml, H₂O₂ scavenging IC₅₀ 0.521 ± 0.015 mg/ml, reducing power IC₅₀ 0.248 ± 0.025 mg/ml and NO scavenging IC₅₀ 0.537 ± 0.038 mg/ml). Two compounds were isolated and when compared with data from the literature; the structures were suggestive of polyphenolic flavonoid, quercetin and 3-O-β-D-glucopyranosyl-sitosterol. The result indicates that H. bonariensis leaves contain bioactive compounds with antioxidant activity.

Keywords: antioxidant, cataract, free radical, flavonoids, hydrocotyl bonariensis

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Authors: Eric Beyegue, Boris Azantza, Judith Laure Ngondi, Julius E. Oben

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Background: It is clearly that phytochemical constituents of plants in relation exhibit free radical scavenging, antioxidant and glycosylation properties. This study investigated the in vitro antioxidant and free radical scavenging, inhibited activities against α-amylase and invertase enzymes of stem bark extracts C. edulis (Olacaceae). Methods: Four extracts (hexane, dichloromethane, ethanol and aqueous) from the barks of C. edulis were used in this study. Colorimetric in vitro methods were using for evaluate free radical scavenging activity DPPH, ABTS, NO, OH, antioxidant capacity, glycosylation activity, inhibition of α-amylase and invertase activities, phenolic, flavonoid and alkaloid contents. Results: C. edulis extracts (CEE) had a higher scavenging potential on the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO), 2, 2-azinobis (3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and glucose scavenging with the IC50 varied between 41.95 and 36694.43 µg/ml depending on the solvent of extraction. The ethanol extract of C. edulis stem bark (CE EtOH) showed the highest polyphenolic (289.10 + 30.32), flavonoid (1.12 + 0.09) and alkaloids (18.47 + 0.16) content. All the tested extracts demonstrated a relative high inhibition potential against α-amylase and invertase digestive enzymes activities. Conclusion: This study suggests that CEE exhibited higher antioxidant potential and significant inhibition potential against digestive enzymes.

Keywords: Coula edulis, antioxidant, scavenging activity, amylase, invertase

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Authors: Salmin Alshalmani, Ghazall M Benhusein, Ebtisam Alhadi Absomaha, Marwa I. Meshri, Hamdoon A. Mohammed, Jamal Mezogi

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Eight wild medicinal plants used by Libyan and growing in Al-Jebel Al-Akhdar, Libya were suspected to estimate the antioxidant activity using 2,2-Diphenyl-1-Picrylhydrazyl stable free radical (DPPH). Incidences of purple colour reduction of the DPPH by testing extracts in addition to quercetin and vitamin C as positive controls reflect its ability to scavenge free radicals. All testing plants extract showed noticeable strength as antioxidant regarding its abilities to scavenge DPPH with an especial regards to Sarcopoterium spinosum.

Keywords: antioxidant, scavenging activity, folk medicine, methanol extracts

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Authors: Zaia Derrar Kaddour

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The study of a beam throughout an optical path is generally achieved by means of diffraction integral. Unfortunately, in some problems, this tool turns out to be not very friendly and hard to implement. Instead, the beam expansion method for computing field profiles appears to be an interesting alternative. The beam expansion method consists of expanding the field pattern as a series expansion in a set of orthogonal functions. Propagating each individual component through a circuit and adding up the derived elements leads easily to the result. The problem is then reduced to finding how the expansion coefficients change in a circuit. The beam expansion method requires a systematic study of each type of optical element that can be met in the considered optical path. In this work, we analyze the following fundamental elements: first order optical systems, hard apertures and waveguides. We show that the former element type is completely defined thanks to the Gouy phase shift expression we provide and the latters require a suitable mode conversion. For endorsing the usefulness and relevance of the beam expansion approach, we show here some of its applications such as the treatment of the thermal lens effect and the study of unstable resonators.

Keywords: gouy phase shift, modes, optical resonators, unstable resonators

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Authors: Salman Ali Nisar, Suzuki Koji

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In this paper we developed a new algorithm to convert the project scheduling time into calendar date in order to handle non-interruptible activities not to be split by non-working days (such as weekend and holidays). In a construction project some activities might require not to be interrupted even on non-working days, or to be finished on the end day of business days. For example, concrete placing work might be required to be completed by the end day of weekdays i.e. Friday, and curing in the weekend. This research provides an algorithm that imposes time constraint for start and finish times of non-interruptible activities. The algorithm converts working days, which is obtained by Critical Path Method (CPM), to calendar date with consideration of the start date of a project. After determining the interruption by non-working days, the start time of a certain activity should be postponed, if there is enough total float value. Otherwise, the duration is shortened by hiring additional resources capacity or/and using overtime work execution. Then, time constraints are imposed to start time and finish time of the activity. The algorithm is developed in Excel Spreadsheet for microcomputer and therefore we can easily get a feasible, calendared construction schedule for such a construction project with some non-interruptible activities.

Keywords: project management, scheduling, critical path method, time constraint, non-interruptible tasks

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Authors: Tai Yuan Yu, Pei-Jen Wang

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Oil-free turbomachinery is considered one of the critical technologies for future green power generation systems as rotor machinery systems. Oil-free technology allows clean, compact, and maintenance-free working, and gas foil bearings, abbreviated as GFBs, are important for the technology. Since the first applications in the auxiliary power units and air cycle machines in the 1970s, obvious improvement has been created to the computational models for dynamic rotor behavior. However, many technical issues are still poorly understood or remain unsolved, and some of those are thermal management and the pattern of how pressure will be distributed in bearing clearance. This paper presents a three-dimensional, abbreviated as 3D, fluid-structure interaction model of single pad foil bearings and three pad foil bearings to predict bearing working behavior that researchers could compare characteristics of those. The coupling analysis model involves dynamic working characteristics applied to all the gas film and mechanical structures. Therefore, the elastic deformation of foil structure and the hydrodynamic pressure of gas film can both be calculated by a finite element method program. As a result, the temperature distribution pattern could also be iteratively solved by coupling analysis. In conclusion, the working fluid state in a gas film of various pad forms of bearings working characteristic at constant rotational speed for both can be solved for comparisons with the experimental results.

Keywords: fluid-structure interaction, multi-physics simulations, gas foil bearing, oil-free, transient thermo-hydrodynamic

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Authors: Zhikai Chena, Renzhong Fu, Wen Chaib, Rongxin Yuanb

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Two eco-benign and highly efficient routes for the synthesis of amides have been developed by treating amines with corresponding carboxylic acids or carboxamides in the presence of heteropolyanion-based ionic liquids (HPAILs) as catalysts. These practical reactions can tolerate a wide range of substrates. Thus, various amides were obtained in good to excellent yields under solvent-free conditions at heating. Moreover, recycling studies revealed that HPAILs are easily reusable for this two procedures. These methods provide green and much improved protocols over the existing methods.

Keywords: synthesis, amide, ıonic liquid, catalyst

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Authors: Indu Elizabeth

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Antimony/Multi Walled Carbon nano tube nanocomposite (Sb/MWCNT) is synthesized using ethylene glycol mediated reduction process. Binder free, self-supporting and flexible Sb/MWCNT nanocomposite paper has been prepared by employing the vacuum filtration technique. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy (RS), and thermal gravimetric analysis (TGA) to evaluate the structure of anode and tested for its performance in a Lithium rechargeable cell. Electrochemical measurements demonstrate that the Sb/MWCNT composite paper anode delivers a specific discharge capacity of ~400 mAh g-1 up to a current density of 100 mA g-1.

Keywords: antimony, lithium ion battery, multiwalled carbon nanotube, specific capacity

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Authors: Gautam Sharda

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The concept of right speech is the third stage of the noble eightfold path as prescribed by the Buddha and followed by millions of practicing Buddhists. The Buddha lays a lot of importance on the notion of right speech (Samma Vacca). In the Angutara Nikaya, the Buddha mentioned what constitutes right speech, which is basically four kinds of abstentions; namely abstaining from false speech, abstaining from slanderous speech, abstaining from harsh or hateful speech and abstaining from idle chatter. The Buddha gives reasons in support of his view as to why abstaining from these four kinds of speeches is favourable not only for maintaining the peace and equanimity within an individual but also within a society. It is a known fact that when we say something harsh or slanderous to others, it eventually affects our individual peace of mind too. We also know about the many examples of hate speeches which have led to senseless cases of violence and which are well documented within our country and the world. Also, indulging in false speech is not a healthy sign for individuals within a group as this kind of a social group which is based on falsities and lies cannot really survive for long and will eventually lead to chaos. Buddha also told us to refrain from idle chatter or gossip as generally we have seen that idle chatter or gossip does more harm than any good to the individual and the society. Hence, if most of us actually inculcate this third stage (namely, right speech) of the noble eightfold path of the Buddha in our daily life, it would be highly beneficial both for the individual and for the harmony of the society.

Keywords: Buddhism, speech, individual, society

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Authors: Y. M. Aiyesimi, S. O. Abah, G. T. Okedayo

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A general analysis has been developed to study the chemical reaction effects on unsteady MHD double-diffusive free convective flow over a vertical stretching plate. The governing nonlinear partial differential equations have been reduced to the coupled nonlinear ordinary differential equations by the similarity transformations. The resulting equations are solved numerically by using Runge-Kutta shooting technique. The effects of the chemical parameters are examined on the velocity, temperature and concentration profiles.

Keywords: chemical reaction, MHD, double-diffusive, stretching plate

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Authors: Gaoyuan Wang, Tian Chen, Junnan Liu

Abstract:

Facing a period of major change that’s rarely seen in a century, China formulates the 14th Five-Year Plan and places emphasis on promoting high-quality development. In this context, the overall urban design has become a crucial and systematic tool for high-quality urban development. However, there are bottlenecks in the nature definition, content scope and transmission mechanisms of the current overall urban design in China. The paper interprets the emerging demands of the 14th Five-Year Plan on urban design in terms of new value-quality priority, new dynamic-space performance, new target-region coordination and new path-refined governance. Based on the new trend and appeal, the multi-dimensional thinking integrated with the major tasks of urban design are proposed accordingly, which is the biomass thinking in ecological, production and living element, the strategic thinking in spatial structure, the systematic thinking in the cityscape, the low-carbon thinking in urban form, the governance thinking in public space, the user thinking in design implementation. The paper explores the possibility of transforming the value thinking and technical system of urban design in China and provides a breakthrough path for the urban planning and design industry to better respond to the propositions of the country’s 14th Five-Year Plan.

Keywords: China’s 14th five-year plan, overall urban design, urban design thinking, transformation of urban design

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Authors: Rex Hsieh, Kosei Yamamura, Satoshi Cho, Hisashi Sato

Abstract:

This project took place in the fall semester of 2019 from September 2019 to February 2020. It improves upon the design of a previous vTuber based eLearning video system by correcting criticisms from students and enhancing the positive aspects of the previous system. The transformed audio which has proven to be ineffective in previous experiments was not used in this experiment. The result is videos featuring 3 avatars covering different Ray Tracing subject matters being released weekly. Students are free to pick which videos they want to watch and can also re-watch any videos they want. The students' subjective impressions of each video is recorded and analysed to help further improve the system.

Keywords: vTuber, eLearning, Ray Tracing, Avatar

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Authors: N. Rajendra Prasad

Abstract:

Resveratrol (RSV), a grape phytochemical, has drawn greater attention because of its beneficial ef-fects against cancer. However, RSV has some draw-backs such as unstabilization, poor water solubility and short biological half time, which limit the utili-zation of RSV in medicine, food and pharmaceutical industries. In this study, we have encapsulated RSV in gelatin nanoparticles (GNPs) and studied its anti-cancer efficacy in NCI-H460 lung cancer cells. SEM and DLS studies have revealed that the prepared RSV-GNPs possess spherical shape with a mean diameter of 294 nm. The successful encapsulation of RSV in GNPs has been achieved by the cross-linker glutaraldehyde probably through Schiff base reaction and hydrogen bond interaction. Spectrophotometric analysis revealed that the max-imum of 93.6% of RSV has been entrapped in GNPs. In vitro drug release kinetics indicated that there was an initial burst release followed by a slow and sustained release of RSV from GNPs. The prepared RSV-GNPs exhibited very rapid and more efficient cellular uptake than free RSV. Further, RSV-GNPs treatment showed greater antiproliferative efficacy than free RSV treatment in NCI-H460 cells. It has been found that greater ROS generation, DNA damage and apoptotic incidence in RSV-GNPs treated cells than free RSV treatment. Erythrocyte aggregation assay showed that the prepared RSV-GNPs formulation elicit no toxic response. HPLC analysis revealed that RSV-GNPs was more bioavailable and had a longer half-life than free RSV. Hence, GNPs carrier system might be a promising mode for controlled delivery and for improved therapeutic index of poorly water soluble RSV.

Keywords: resveratrol, coacervation, anticancer gelatin nanoparticles, lung cancer, controlled release

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Authors: M. Sikoń, E. Bidzińska

Abstract:

An attempt to apply EPR (Electron Paramagnetic Resonance) spectroscopy to experimental analysis of the mechanical state of the loaded material is considered in this work. Theory concerns the participation of electrons in transfer of mechanical action. The model of measurement is shown by applying classical mechanics and quantum mechanics. Theoretical analysis is verified using EPR spectroscopy twice, once for the free spacemen and once for the mechanical loaded spacemen. Positive results in the form of different spectra for free and loaded materials are used to describe the mechanical state in continuum based on statistical mechanics. Perturbation of the optical electrons in the field of the mechanical interactions inspires us to propose new optical properties of the materials with mechanical stresses.

Keywords: Cosserat medium, EPR spectroscopy, optical active electrons, optical activity

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Authors: Caner Koc, Dilara Gerdan Koc, Emrah Saka, H. Ibrahim Karagol

Abstract:

The use of pesticides in agricultural activities is the most harmful to the environment and farmers' health, and it also has the greatest input prices, along with fertilizers. In this study, an electric, electrostatically charged, autonomous agricultural robot was developed, modeled, and prototyped and manufactured. It allows for sensitive pesticide applications with variable levels, has controllable spray nozzles, and uses camera distance sensors to detect and spray into tree canopies. The created prototype was produced with flexibility in mind. Two stages of prototype manufacture were completed. The initial stage involved designing and producing the flexible primary body of the autonomous vehicle. Detachable hanger assemblies are employed so that the main body robot can perform a variety of agricultural tasks. The design of the spraying devices and their fitting to the autonomous vehicle was completed as the second stage of the prototype. The built prototype spraying robot's itinerary was planned using the free, open-source program Mission Planner. PX4, telemetry, and RTK GPS are used to maneuver the autonomous car along the designated path. To avoid potential obstructions, the robot uses ultrasonic and lidar sensors. The developed autonomous vehicle's energy needs are intended to be met entirely by electric batteries. In the event that the batteries run out of power, the sockets are set up to be recharged both by using the generator and the main power source through the specifically constructed panel.

Keywords: autonomous agricultural robot, pesticide, smart farming, spraying, variable rate application

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Authors: Mike Wei, Mario Cedillo, Jiahui Lin, Carol Lorraine Storey-Johnson, Carla Boutin-Foster

Abstract:

Purpose: The extent to which health insurance enrollment succeeds under the Affordable Care Act (ACA) rests heavily on the ability to reach the uninsured and motivate them to enroll. We sought to identify perceptions about the ACA among uninsured patients at a free clinic in New York City. Background: The ACA holds tremendous promise for reducing the number of uninsured Americans. As of April 2014, nearly 8 million people had signed up for health insurance through the Health Insurance Marketplace. Despite this early success, future and continued enrollment rests heavily on the degree of public awareness. Reaching eligible individuals and increasing their awareness and understanding remains a fundamental challenge to realizing the full potential of the ACA. Reaching out to uninsured patients who are seeking care through safety net facilities such as free clinics may provide important avenues for reaching potential enrollees. This project focuses on the experience at the free clinic at Weill Cornell Medical College, the Weill Cornell Community Clinic (WCCC), and seeks to understand perceptions about the ACA among its patient population. Methods: This was a cross-sectional study of all patients who visited the free clinic at Weill Cornell Medical College, the Weill Cornell Community Clinic, from July 2013 to May 2014. Patients who provided informed consent at their visit and completed a semi-structured questionnaire were included (N=62). The questionnaire comprised of questions about demographic characteristics and open-ended questions about their knowledge and perception of the impact of the ACA. Descriptive statistics were used to characterize the population demographics. Qualitative coding techniques were used for open-ended items. Results: Approximately one third of patients surveyed never had health insurance. Of the remaining 65%, 20% lost their insurance within the past year. Only 55% had heard about the ACA, and only 10% knew about the Health Benefits Exchange. Of those who had heard about the ACA, sentiments were tinged with optimistic misperceptions, such as “it will be free health care for all.” While optimistic, most of the responses focused on the economic implications of the ACA. Conclusions: These findings reveal the immense amount of misconception and lack of understanding with regards to the ACA. As such, the study highlights the need to educate and address the concerns of those who remain skeptical or uncertain about the implications of the ACA.

Keywords: Affordable Care Act, demographics, free clinics, underserved.

Procedia PDF Downloads 390