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Open Access March 30, 2023

Pulsatile Blood Flow Simulation for Subject-Specific Geometry of a Human Aortic Arch

Abstract Pulsatile blood flow in a subject-specific human aortic arch and its major branches is studied computationally for a peak Reynolds number of 1553 and a Womersley number of 22.74. The aortic geometry is constructed from the CT-scan images of a subject. The aorta has out-of-plane curvature and significant area variation along the flow direction. A physiologically representative pulsatile velocity [...] Read more.
Pulsatile blood flow in a subject-specific human aortic arch and its major branches is studied computationally for a peak Reynolds number of 1553 and a Womersley number of 22.74. The aortic geometry is constructed from the CT-scan images of a subject. The aorta has out-of-plane curvature and significant area variation along the flow direction. A physiologically representative pulsatile velocity waveform is applied as boundary condition at the inlet of the aorta. The primary velocity profiles are skewed towards the inner wall of the ascending aorta during the entire cardiac cycle. In the decelerating phase, reverse flow is noted along the inner wall and the magnitude of maximum velocity is about 50 % of the peak flow condition. Flow separation is observed in the inner wall of the ascending aorta during the decelerating and reverse flow phases of the cardiac cycle. In the accelerating phase, however, flow separation does not occur. The major observation of the present work is the existence of complex and asymmetrical vortical flow structures which are not observed either in simple curved pipes or in idealized aortic arch computational studies. The relative strength of the secondary flow with respect to the primary flow is quantified by means of Relative Secondary Kinetic Energy whose highest value is evaluated to be 1.202 occurring near the entrance of the right carotid artery during the maximum reverse flow condition. High values of wall shear stress is observed at distal of the left and right subclavian arteries, the bifurcation of brachiocephalic artery between right subclavian artery and right carotid artery, and proximal inner wall of descending aorta during the cardiac cycle. The wall shear stress at the bifurcations of the branches are low and oscillatory and generally correlates with the preferential sites for atherosclerosis. The flow structures on the aorta wall are explicitly highlighted by the limiting streamlines. The application of limiting streamlines to clearly elucidate the complex on-wall flow structures is one of the key contributions of the present study. During the decelerating and reverse flow phases several critical points are observed on the aortic wall. These complex flow structures vanish during the accelerating phase. The observations made in the present study will be helpful in creating accurate and clinically useful computational models.
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Open Access December 22, 2023

Cloud Based Payment Processing and Merchant Services: A Scalable and Secure Framework for Digital Transactions in a Globalized Economy

Abstract In today’s world of a globalized economy and ubiquitous digital transactions, businesses are hungry for ways to increase transaction efficiency and security. In the real economy, solutions that scale to fit transaction volume or velocity are equally valuable. This is true for clearing and settlement and for the day-to-day needs of buyers and sellers alike. Clever observers of both cash and digital [...] Read more.
In today’s world of a globalized economy and ubiquitous digital transactions, businesses are hungry for ways to increase transaction efficiency and security. In the real economy, solutions that scale to fit transaction volume or velocity are equally valuable. This is true for clearing and settlement and for the day-to-day needs of buyers and sellers alike. Clever observers of both cash and digital transactions can spot cases where technology that supports transaction security or safety can strengthen consumer-borrower ties, mitigate default risks, and reduce recidivism. In general, a cloud solution for payment processing and merchant services solves two major barriers to optimum business technology: lack of scalability and lack of security [1]. The extension of current practice has its advantages, but new solutions unlock significant opportunities for both consumers and financial institutions [2]. The focus of this work is on the provisioning of cloud-based payment processing and merchant services to financial institutions and established global organizations, although the options available with these services mean they are potentially applicable to a wide range of group entities, including non-trading organizations, pension administrators, and group treasurers. With the increased attention to cybersecurity, a mass of data is available to assist the IT departments of the major payment processors, merchants, and acquirers to get cybersecurity on the radar of C-level executives [3]. The case is put forward for the increased targeting of and reporting to the Board’s Audit, Risk, and Liability Committees of publicly held payment processors and merchants to reduce fraud losses and mitigate the reputation and class action lawsuit risk due to data breaches. The progress of technology in the payment sector requires all stakeholders to have a collective approach in order to mitigate fraud and cybersecurity-related risks in new products and services to enhance consumer confidence and the proportion of retail cashless transactions [4].
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Open Access October 18, 2022

Assessment of the Effects of Sensors Misalignment of a Multi-Beam Hydrographic Survey

Abstract A hydrographic survey vessel shows three -dimensional movements (Roll, Pitch and Heave) misalignment with respect to the vessel reference unit (VRU) due to environmental effects, such as wind, current, other vessel wakes, etc. These motions if ignored, cause errors in measured depth and in the positioning of the sounding. Hence the need of a motion sensor and gyroscope. However, the alignment of [...] Read more.
A hydrographic survey vessel shows three -dimensional movements (Roll, Pitch and Heave) misalignment with respect to the vessel reference unit (VRU) due to environmental effects, such as wind, current, other vessel wakes, etc. These motions if ignored, cause errors in measured depth and in the positioning of the sounding. Hence the need of a motion sensor and gyroscope. However, the alignment of the multi-beam sonar head to the motion sensor and gyro (Octant) is critical to the accuracy of the determined depths. It is not possible to install the sonar head in perfect alignment with the motion sensor and gyroscope to the accuracy required. The synchronization of the GPS time with the Motion sensor and gyro, the latency of the position, as reported by the GPS as well as the velocity of sound in water are important parameters to account for the misalignment of the motion senor and the multi beam sonar head; this is called the Patch Test. In view of this, a patch test was done to ascertain the mounting angles of EMB 2058 Multi-beam sonar with Octan V installed onboard a survey vessel (Bitam). The result of the Patch test gives a row, pitch and heading value of -1.242Ëš, -4.92Ëš, and -0.48Ëšrespectively. The speed of sound in water as measured ranges from; 1531.47m/s to 1531.60m/s within a minimum cast depth of 0.49m and maximum cast depth of 16.00m. The statistical analysis gives and average error of 2.642cm/m2 which was within acceptable standard as define by the International Hydrographic Organization (IHO).
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Open Access June 27, 2022

Development of Cellulose Nanofibre (CNF) Coating on (1) Metal Surface for Free Standing CNF Film and (2) Paper Substrates for CNF Barrier Laminates

Abstract Paper is widely used in packaging applications and is biodegradable and therefore perfectly safe as green packaging wrap for the environment. The hydrophilic nature of cellulose fibrils limits the water vapour and oxygen barrier properties of paper. To mitigate these limitations, paper is often associated with other materials, such as plastics, wax and aluminum, for achieving their good barrier [...] Read more.
Paper is widely used in packaging applications and is biodegradable and therefore perfectly safe as green packaging wrap for the environment. The hydrophilic nature of cellulose fibrils limits the water vapour and oxygen barrier properties of paper. To mitigate these limitations, paper is often associated with other materials, such as plastics, wax and aluminum, for achieving their good barrier properties. However, these materials suffer from serious environmental issues, as difficult and inefficient to recycle. Recently, cellulose nanofibre (CNF) based materials has been considered as an alternative to produce eco-friendly barrier materials. Existing techniques to prepare cellulose nanofibre films/sheets/composites/ laminates on the paper substrates are commercially not feasible and expensive. Therefore, other cost effective and readily implementable methodologies are required to achieve cellulose nanofibre barrier layers. In the present report, a novel approach is developed using spray coating technique to produce CNF materials with excellent barrier properties. Among many coating techniques, the spray coating has many advantages such as the production of even coating surface on the base sheet and contactless coating with the substrate. A laboratory scale spray coating of cellulose nanofibre suspension on a paper substrate was developed. When the cellulose nanofibre suspension concentration was varied from 0.5 to 1.5 wt. %, coat weight is increased from 2.9±0.7 to 29.3±6.9 g/m2. As a result, the air permeability of composite was decreased 0.78±0.17 to <0.0030 µm/Pa.s. Scanning electron microscopy studies of spray coated CNF laminates on the paper confirms that the surface pores in the paper substrates are filled with sprayed cellulose nanofibre and forms a continuous film on the surface of the substrate. These are the probable reasons for the reduction of air permeability of composites. A rapid preparation technique to prepare free standing cellulose nanofibre films/sheets was also developed using a bench scale spray coating system. Cellulose nanofibre suspension with concentration ranging from 1 to 2 wt% was sprayed onto a stainless steel plate, which is moving on a conveyor at a velocity of 0.32 cm/sec and then air dried. The basis weight of produced cellulose nanofibre films is varied from 52.8±7.4 to 193.1±3.4 g/m2. Processing time taken to prepare films was approximately 1.0 min, which is much less than processing times reported in the previous literature. Thus, the significant reduction in preparation time for producing the cellulose nanofibre sheet recommends that this spray coating technique can be utilized for the development of a scalable process for the fabrication of various cellulose based nanocomposite. Therefore, the laboratory scale spray coating confirms that the spraying could provide a platform for development of films/sheets/nanocomposite and also a CNF barrier layer on the base sheet. The future work is the development of a continuous spray coating of cellulose nanofibre on the base sheet and evaluation of mechanical and barrier properties spray coated barrier layers on the base sheet.
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Open Access June 09, 2022

Characterization of Electromagnetic Wave Propagation on Coaxial Cables

Abstract This research work is about the propagation of electromagnetic waves on coaxial cables such that its resistive losses are minimized, and signal quality is improved. The resistive loss of a coaxial cable is caused by several things; impedance of the conductor, and the type of dielectric material used and the skin effect and causes the signal to be attenuated. In this research, various comparison [...] Read more.
This research work is about the propagation of electromagnetic waves on coaxial cables such that its resistive losses are minimized, and signal quality is improved. The resistive loss of a coaxial cable is caused by several things; impedance of the conductor, and the type of dielectric material used and the skin effect and causes the signal to be attenuated. In this research, various comparison was made on different coaxial cables in other to test their resistivity per length of the conductor and measure the losses per meter of the coaxial cables. The various properties of the conductor, the impedance, capacitance, and the velocity of propagations was taken into consideration. Measurements were carried out to derive our data, and MATLAB was used in analyzing the results and the behaviour of the LMR series, RG8, RG6A, Davis RF, and CQ110 coaxial cables. Based on the findings, it is concluded that for a better and improved signal quality and to reduce resistive losses in coaxial cables, the characteristic impedance of the cable should be 80 ohms as this will reduce the coaxial cable resistive losses.
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Open Access July 22, 2021

Acoustic Properties of Musanga Cecrepoides Wood Samples Obtained from Different Stem Positions in Niger Delta Region of Nigeria

Abstract Musanga cecrepoides is an interesting wood species due to its diverse utility ranging from medicine, shade, ornaments etc. Research has been conducted on other properties of this wood species with little information about its acoustic properties. Thus, the evaluation of its acoustic properties is pertinent so as to increase the information bank of its properties. This study assessed the acoustic properties of Musanga cecrepoides wood obtained from selected states and locations in the Niger Delta region of Nigerian viz a vis, Rivers, Bayelsa and Delta States. Test samples were collected from different stem positions axially (top, middle, base) and radially (inner and outer) and analyzed using the statistical software package IBM SPSS Statistics, Version 23 (IBM Corporation, New York, USA). Analysis of variance (ANOVA) was performed at 5% level of significance to determine whether the assessed acoustic properties were significantly different among different stem positions. Results showed that sound frequency (f) at top wood (3061.71 Hz) and outer wood (3096.06 Hz) had significantly higher resonance frequency compared with the bottom wood (2768.01 Hz) and inner wood (2349.54 Hz) respectively. The mean sound velocity (v) at both the axial (2069.59 m/s) and radial (1905.96 m/s) stem positions fell short of the estimated mean v of other wood species when compared. However, such result is suitable for other acoustic purposes with moderate sound velocity. The sound radiation coefficient (R) values were highest at the bottom (4.18) axially and outer (4.13) radially when compared to other stem orientations of the wood. Whereas axially at the top (1561815.86 Kg/(m2s)) and radially at the outer position (1558292.53 Kg/(m2s) Sound Impedance (z) was highest when compared with other stem positions of the Musanga cecrepoides [...] Read more.
Musanga cecrepoides is an interesting wood species due to its diverse utility ranging from medicine, shade, ornaments etc. Research has been conducted on other properties of this wood species with little information about its acoustic properties. Thus, the evaluation of its acoustic properties is pertinent so as to increase the information bank of its properties. This study assessed the acoustic properties of Musanga cecrepoides wood obtained from selected states and locations in the Niger Delta region of Nigerian viz a vis, Rivers, Bayelsa and Delta States. Test samples were collected from different stem positions axially (top, middle, base) and radially (inner and outer) and analyzed using the statistical software package IBM SPSS Statistics, Version 23 (IBM Corporation, New York, USA). Analysis of variance (ANOVA) was performed at 5% level of significance to determine whether the assessed acoustic properties were significantly different among different stem positions. Results showed that sound frequency (f) at top wood (3061.71 Hz) and outer wood (3096.06 Hz) had significantly higher resonance frequency compared with the bottom wood (2768.01 Hz) and inner wood (2349.54 Hz) respectively. The mean sound velocity (v) at both the axial (2069.59 m/s) and radial (1905.96 m/s) stem positions fell short of the estimated mean v of other wood species when compared. However, such result is suitable for other acoustic purposes with moderate sound velocity. The sound radiation coefficient (R) values were highest at the bottom (4.18) axially and outer (4.13) radially when compared to other stem orientations of the wood. Whereas axially at the top (1561815.86 Kg/(m2s)) and radially at the outer position (1558292.53 Kg/(m2s) Sound Impedance (z) was highest when compared with other stem positions of the Musanga cecrepoides wood.
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Open Access October 15, 2022

Big Data and AI/ML in Threat Detection: A New Era of Cybersecurity

Abstract The unrelenting proliferation of data, entwined with the prevalence of mobile devices, has given birth to an unprecedented growth of information obscured by noise. With the Internet of Things and myriad endpoint devices generating vast volumes of sensitive and critical data, organizations are tasked with extracting actionable intelligence from this deluge. Governments and enterprises alike, even [...] Read more.
The unrelenting proliferation of data, entwined with the prevalence of mobile devices, has given birth to an unprecedented growth of information obscured by noise. With the Internet of Things and myriad endpoint devices generating vast volumes of sensitive and critical data, organizations are tasked with extracting actionable intelligence from this deluge. Governments and enterprises alike, even under pressure from regulatory boards, have strived to harness the power of data and leverage it to enhance safety and security, maximize performance, and mitigate risks. However, the adversaries themselves have capitalized on the unequal battle of big data and artificial intelligence to inflict widespread chaos. Therefore, the demand for big data analytics and AI/ML for high-fidelity intelligence, surveillance, and reconnaissance is at its highest. Today, in the cybersecurity realm, the detection of adverse incidents poses substantial challenges due to the sheer variety, volume, and velocity of deep packet inspection data. State-of-the-art detection techniques have fallen short of detecting the latest attacks after a big data breach incident. On the other hand, computational intelligence techniques such as machine learning have reignited the search for solutions for diverse monitoring problems. Recent advancements in AI/ML frameworks have the potential to analyze IoT/edge-generated big data in near real-time and assist risk assessment and mitigation through automated threat detection and modeling in the big data and AI/ML domain. Industry best practices and case studies are examined that endeavor to showcase how big data coupled with AI/ML unlocks new dimensions and capabilities in improved vigilance and monitoring, prediction of adverse incidents, intelligent modeling, and future uncertainty quantification by data resampling correction. All of these avenues lead to enhanced robustness, security, safety, and performance of industrial processes, computing, and infrastructures. A view of the future and how the potential threats due to the misuse of new technologies from bandwidth to IoT/edge, blockchain, AI, quantum, and autonomous fields is discussed. Cybersecurity is again playing out at a pace set by adversaries with low entry barriers and debilitating tools. The need for innovative solutions for defense from the emerging threat landscape, harnessing the power of new technologies and collaboration, is emphasized.
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Open Access December 27, 2019

Revolutionizing Patient Care and Digital Infrastructure: Integrating Cloud Computing and Advanced Data Engineering for Industry Innovation

Abstract This work details how the integration of cloud computing and advanced data engineering can innovate and reshape patient care and digital infrastructure. In the healthcare sector, cloud services offer the necessary support to generate digitally-oriented services and service kits. These services can contain high levels of availability, low levels of latency, and on-demand scaling capabilities, while [...] Read more.
This work details how the integration of cloud computing and advanced data engineering can innovate and reshape patient care and digital infrastructure. In the healthcare sector, cloud services offer the necessary support to generate digitally-oriented services and service kits. These services can contain high levels of availability, low levels of latency, and on-demand scaling capabilities, while following the strictest data protection laws and regulations. On the other hand, these services can be combined with data engineering techniques to construct an ecosystem that enhances and adds an optimized data layer on any cloud environment. This ecosystem includes technologies to acquire, process, and manage healthcare data while respecting all regulatory obligations and institutions and can be part of a comprehensive digitalization strategy. The objective is to augment the healthcare services that the industry offers by leveraging healthcare data and AI technologies. Designed services, processes, and technologies can be described either as industry-agnostic services or healthcare-specific services that process and manage electronic healthcare records (EHR). Industry-agnostic services offer a set of tools and methodologies to conduct optimized data experiments. The goal is to exploit any variety, velocity, volume, and veracity of medical data. Healthcare-specific services offer a set of tools and methodologies to connect to any common EHR vendor in a privacy-preserving manner. Participating companies are thus able to hold, share, and make use of healthcare data in real-time. The proposed architecture can be transformative for the healthcare industry, opening up and facilitating experimentation on new and scalable service models. The transition to a more digital health approach would help overcome the limits encountered in traditional settings. Limitations in the availability of healthcare facilities and healthcare professionals have underpinned the increasing share of telemedicine in the care process. However, the record-keeping of the patients that undergo care outside of traditional healthcare facilities is often missing and can severely influence the continuity of treatment. Identifying new methods to implement disease prevention and early intervention processes is crucial to avoid more extensive treatment and to support those on multiple line therapies. For chronic patients, having a service available that monitors the state of health and intervenes when parameters go off the wanted range is crucial. However, the same patients are the most under the influence of the decision of care providers; a second opinion might be given remotely which the patient can access at any time on-demand. To address these different kinds of services, an ecosystem composed of a dictionary's worth data layer is outlined, able to live and operate seamlessly in any cloud environment. This future work's envisioned outcome is the rapid evolution and re-definition of the European healthcare landscape.
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