Hasil untuk "Electrical engineering. Electronics. Nuclear engineering"

Changhua Bao, Vincent Eggers, Manuel Meierhofer et al.

Abstract Dispersionless electronic bands lead to an extremely high density of states and suppressed kinetic energy, thereby increasing electronic correlations and instabilities that can shape emergent ordered states, such as excitonic, ferromagnetic, and superconducting phases. A flat band that extends over the entire momentum space and is well isolated from other dispersive bands is, therefore, particularly interesting. Here, the band structure of the van der Waals crystal NbOCl2 is revealed by utilizing photoelectron momentum microscopy. We directly map out an electronic band that is flat throughout the entire Brillouin zone and features a width of only  ~ 100 meV. This band is well isolated from both the conduction and remote valence bands. Moreover, the quasiparticle band gap shows a high tunability upon the deposition of cesium atoms on the surface. By combining the single-particle band structure with the optical transmission spectrum, the optical gap is identified. The fully isolated flat band in a van der Waals crystal provides a qualitatively new testbed for exploring flat-band physics.

Anthony Pennes, K. Mendez, N. Hanumara et al.

Best practices in Biomedical Engineering education seek to connect classroom knowledge to practical applications. MIT’s Medical Device Design course is comprised of in-class didactics, individual laboratory assignments, and a semester-long, team- based design and prototyping challenge, based in real unmet biomedical need. Students in the course represent a broad set of undergraduate and graduate students, from diverse educational backgrounds, with different levels of training and expertise. This year, as a precursor to the semester-long project, we designed, piloted, and evaluated a new experiential learning lab based around a syringe pump, selected because of its prevalence in the clinical setting, exemplification of core, multidisciplinary biomedical engineering concepts, and suitability for a team-based learning exercise. Students individually calculated patient dosing requirements and translated desired volume and flow rate into stepper motor commands. Then, during a single in-class session, teams worked from a custom-designed and fabricated kit to assemble a syringe pump, breadboard electronics, implement software controls, and finally close the design loop by evaluating their pumps' dispensing performance. A post-lab survey of the student cohort indicated that this pilot lab provided a sound biomedical learning and teamwork opportunity that improved technical literacy. The survey also identified key opportunities for improvement – students wanted more time and instructor-guided learning to increase their understanding of the mechanical engineering, electrical engineering, and software subtopics. Consequently, next year we will expand the lab into a multi-class exercise, with enhanced lectures and supplementary materials. Overall, we share this problem-based learning exercise, designed to exemplify key concepts, improve teamwork, and foster hands-on tinkering skills, with other biomedical engineering instructors.

Sedigheh Aghayari

Mohamed R. Abdelhamid, Unsoo Ha, Utsav Banerjee et al.

The past few years have witnessed a growing interest in wireless and batteryless implants, due to their potential in long-term biomedical monitoring of in-body conditions, such as internal organ movements, bladder pressure, and gastrointestinal health. Early proposals for batteryless implants relied on inductive near-field coupling and ultrasound harvesting, which require direct contact between the external power source and the human body. To overcome this near-field challenge, recent research has investigated the use of RF backscatter in wireless micro-implants because of its ability to communicate with wireless receivers that are placed at a distance outside the body <inline-formula> <tex-math notation="LaTeX">$(\sim 0.5$ </tex-math></inline-formula> m), allowing a more seamless user experience. Unfortunately, existing far-field backscatter designs remain limited in their functionality: they cannot perform biometric sensing or secure data transmission; they also suffer from degraded harvesting efficiency and backscatter range due to the impact of variations in the surrounding tissues. In this article, we present the design of a batteryless, wireless and secure system-on-chip (SoC) implant for in-body strain sensing. The SoC relies on four features: 1) employing a reconfigurable in-body rectenna which can operate across tissues adapting its backscatter bandwidth and center frequency; 2) designing an energy efficient 1.37 mmHg strain sensing front-end with an efficiency of 5.9 mmHg<inline-formula> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula>nJ/conversion; 3) incorporating an AES-GCM security engine to ensure the authenticity and confidentiality of sensed data while sharing the ADC with the sensor interface for an area-efficient random number generation; 4) implementing an over-the-air closed-loop wireless programming scheme to reprogram the RF front-end to adapt for surrounding tissues and the sensor front-end to achieve faster settling times below 2 s.

Cheng Yu, Long Li, Shiwen Wang et al.

Nanomaterials (NMs) have increasingly been used for the diagnosis and treatment of head and neck cancers (HNCs) over the past decade. HNCs can easily infiltrate surrounding tissues and form distant metastases, meaning that most patients with HNC are diagnosed at an advanced stage and often have a poor prognosis. Since NMs can be used to deliver various agents, including imaging agents, drugs, genes, vaccines, radiosensitisers, and photosensitisers, they play a crucial role in the development of novel technologies for the diagnosis and treatment of HNCs. Indeed, NMs have been reported to enhance delivery efficiency and improve the prognosis of patients with HNC by allowing targeted delivery, controlled release, responses to stimuli, and the delivery of multiple agents. In this review, we consider recent advances in NMs that could be used to improve the diagnosis, treatment, and prognosis of patients with HNC and the potential for future research.

Hong-Hsu Yen, Cheng-Han Lin, Hung-Wei Tsao

Because of toxic gases and fast propagation speed, smoke causes the major injuries and deaths than burns in the fire. Deploying IoT enabled smoke sensors not only help to sense, collect, and transmit the smoke data to the control station, but also enable a dynamic and real-time evacuation approach to increase the evacuation success probability. In this paper, two smoke-aware evacuation approaches are proposed. The individual evacuation mathematical model and the associated SIEP algorithm are first devised to identify a fastest smoke toxic safe evacuation path for an evacuee. Next, the group evacuation mathematical model and the associated SGEP algorithm are devised to evacuate as many evacuees as possible in considering the smoke toxicity and flow congestion along the evacuation routes. SGEP circumvents the congestion problem by scheduling the evacuation sequence according to evacuee&#x2019;s accumulated smoke toxicity value, where higher accumulated smoke toxicity value has higher evacuation priority to prevent incapacitation at evacuation. The FDS simulations based on the real layout of Taipei 101 mall are performed to compare the evacuation success probability between SIEP and SGEP at methane fire and PVC fire. The simulation results show that smoke from PVC fire is more toxic than that of methane fire. In addition, enabling sprinklers can reduce the percentage of toxic nodes up to 41&#x0025; at methane fire and up to 10&#x0025; at PCV fire, as compared to not enabling them. These results indicate that it is more challenging to evacuate at PVC fire than at methane fire. The simulation results in SGEP and SIEP justify the above conclusions where the success evacuation probability differences between methane fire and PVC fire are up to 39&#x0025; (i.e., 100&#x0025; and 61&#x0025;) and 52.5&#x0025; (i.e., 82.5&#x0025; and 30&#x0025;) for SGEP and SIEP, respectively. The simulation results also show that SGEP outperforms SIEP in terms of evacuation success probability at all simulation settings, especially when large number of evacuees are to be evacuated. At methane fire, the largest evacuation success probability difference between SGEP and SIEP is 68.1&#x0025; at 1000 evacuees, 0.3 FED threshold and without sprinklers. At PVC fire, the largest difference is 50&#x0025; at 1000 evacuees, 0.5 FED threshold and with sprinklers. These significant differences in evacuation success probability come from the evacuation congestion in SIEP. The evacuation scheduling approach based on accumulated smoke toxicity policy enables SGEP to circumvent the evacuation congestion, and to get better evacuation success probability. Besides identifying safe evacuation route and evacuation scheduling policy during congestion to evacuate more evacuees, another contribution of this paper is to identify the critical percentage of toxic nodes for safe fire evacuation and rescue operations.

LV Xue-fei, LV Ying, LU Hong-jie, GAN Shu-kun, SHI Long

In order to improve the corrosion resistance of the copper alloy surface, the synergistic effect of La2O3&#x00A0;nanoparticles and silane was studied. The formula of the basic silane treatment solution containing silane (PropS-SH) was obtained by orthogonal experiment, and the surface morphology and structure of the copper alloy after treatment were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Moreover, the effects of La2O3&#x00A0;nanoparticles and silane on the surface properties of copper alloys were analyzed by electrochemical testing methods such as AC impedance. Results showed that the addition of La2O3&#x00A0;nanoparticles and silane enabled the formation of a dense and uniform La/silane composite film on the surface of the copper alloy specimens, which improved the corrosion resistance of the copper alloy. That is to say, La2O3&#x00A0;nanoparticles and silane possessed a synergistic effect on the corrosion resistance of the copper alloy, and the effect was better than traditional BTA passivation effect.

M. Mahgoub, S. Hanna, H. Mostafa

Tow-phase flow is incorporated in all thermal equipments which involve flow boiling. Tow-phase single component flow is an extremely important system in the fields of thermal and nuclear engineering. To carry out the experimental study in this work a test rig has been constructed and built. The test section is a vertical 3 tube-bundle connected electrically in parallel. They are arranged in triangular shape. Each tube is 10/12 mm diameters and 200 cm in length. From the obtained experimental results, it is concluded that the total pressure drop in two-phase flow is found to increase with increasing void fraction (quality). In addition, it was found that the deviation between both experimental and theoretical pressure drop lies in the range from -2 to + 20%.

T. Vaimann, M. Stępień, A. Rassõlkin et al.

The rapid restrictions related to the COVID-19 pandemic, also known as the coronavirus pandemic, has changed the face-to-face education principles that were developed during the centuries and became the main way to transfer knowledge in higher education institutes. The distance learning is challenging for the students and makes it hard for educators to track and evaluate the student's progress. Distance learning is more challenging for the technical education, where the practical courses plays significant role in educational process. In this paper, the modifications taken place in Department of Electrical Power Engineering and Mechatronics at Tallinn University of Technology (Tallinn, Estonia) and Department of Power Electronics, Electrical Drives and Robotics at Silesian University of Technology (Gliwice, Poland) are analyzed. The experience in preparation of additional electronical materials for the students and elements of hybrid education taken in recent years was the key factor for a fast and successful transfer of technical education into distant learning.

Ella Schoolaert, Luisa Cossu, Jana Becelaere et al.

This work shows the design of highly porous membranes with tunable wettability based on poly(2-n-propyl-2-oxazoline) (PnPrOx) nanofibers. Wicking and advanced contact angle experiments demonstrate the high potential for applications requiring specific interactions with aqueous media. PnPrOx is a popular member among the biocompatible poly(2-oxazoline)s due to its thermoresponsiveness in aqueous solutions, enabling the production of ‘smart materials’. On material level, however, many interesting properties of this polymer remain undiscovered. Electrospinning is an ideal technique to transfer the properties observed in solutions to end-material properties, as the polymer is processed into highly porous, nanofibrous membranes. PnPrOx' electrospinnability is here investigated in environmentally friendly ethanol/water solvent systems, ensuring industrial scalability. The nanofibrous membranes show increased hydrophobicity exhibiting the rose-petal effect. Upon functionalization with tannic acid, the hydrophobic membranes are transformed into hydrophilic nanofibers showing water-stability in both fresh and salty water, even below the polymer cloud point temperature. By varying the tannic acid amount, the hydrophilicity can be fine-tuned as the contact area between water droplets and surface, the rate and manner of water uptake and the extent of the rose-petal effect can be manipulated easily. Hence an interesting material is designed for applications in which water caption and transport are important.

Jeongsu Park, Dong Hoon Lee

Cloud services with powerful resources are popularly used to manage exponentially increasing data and to carry out data mining to analyze the data. However, a data mining involving query can cause privacy problems by disclosing both the data and the query. One task in data mining, classification, is used in a wide range of applications, and we focus on k-nearest neighbor (kNN) in this study to realize classification. Although several studies have already attempted to address the privacy problems associated with kNN computation in a cloud environment, the results of these studies are still inefficient. In this paper, we propose a very efficient and privacy-preserving kNN classification (PkNC) over encrypted data. While the amount of computation (encryptions/decryptions and exponentiations) and communication of the most efficient kNN classification proposed in prior studies is bounded by O(kln), that of the proposed PkNC is bounded by O(ln), where l is the domain size of data and n is the number of data. When conducting experiments with the same dataset, the prior kNN classification took 12.02 to 55.5 minutes but PkNC took 4.16 minutes. Furthermore, since PkNC allows to be carried out in parallel for each data, its performance can be improved extremely if it is carried out on machine to allow more numerous threads. PkNC protects the privacy of dataset, input query including the kNN result, and does not disclose any data access patterns. We propose several protocols to serve as building blocks to construct PkNC and formally prove their security. In particular, we propose efficient protocols that privately find k largest or smallest elements in array.

Hanif Ullah, Mamun Abu-Tair, Sally McClean et al.

Abstract Cooperative aerial wireless networks composed of small unmanned aerial vehicles(UAVs) are easy and fast to deploy and provide on the fly communication facilities in situations where part of the communication infrastructure is destroyed and the survivors need to be rescued on emergency basis. In this article, we worked on such a cooperative aerial UAV-based wireless network to connect the two participating stations. The proposed method provides on the fly communication facilities to connect the two ground stations through a wireless access point (AP) mounted on a UAV using the IEEE 802.11a/b/g/n. We conducted our experiments both indoor and outdoor to investigate the performance of IEEE 802.11 protocol stack including a/b/g/n. We envisioned two different cases: line of sight (LoS) and non-line of sight (NLoS). In LoS, we consider three different scenarios with respect to UAV altitude and performed the experiments at different altitudes to measure the performance and applicability of the proposed system in catastrophic situations and healthcare applications. Similarly, for NLoS, we performed a single set of experiments in an indoor environment. Based on our observations from the experiments, 802.11n at 2.4 GHz outperforms the other IEEE protocols in terms of data rate followed by 802.11n at 5 GHz band. We also concluded that 802.11n is the more suitable protocol that can be practiced in disastrous situations such as rescue operations and healthcare applications.

Motselisi Chere, T. Ngqondi, Mncedisi J. Bembe

With the rapidly growth of wireless technologies connecting to the Internet of Things (IoT) there is a challenge of selecting correct wireless low power area networks for IoT applications. IPv6 over Low power Wireless Personal Area Networks. (6LoWPAN) is an open standard developed by the Internet Engineering Task Force (IETF) Working Group (WG) through the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 to minimise header overhead. This led to the development of multiple stack headers for 6LoWPAN, which is similar to one of the IPv6 designs. Therefore, this survey investigates the wireless low power area networks in IoT for 6LoWPAN connectivity with IEEE 802.15.4 standard. The analysis of the opportunities offered in this new technology, the 6LoWPAN, will contribute towards literature and provide guidance with a broader perception on the architecture of 6LoWPAN and routing requirements for deployment.

B. Subramanian, N. Srivastava, S. Bagchi et al.

Solid State Lighting is a rapidly growing new technology in the field of lighting. By utilizing the concepts of solid-state physics and electronics, it generates light. Light emitting diodes and organic light emitting diodes pose several advantages over the current lighting technology but they still require development and research for using them to their full potential. In this paper the characteristics, sources of uncertainty, and market status of light emitting diode are reviewed to provide more suitable research directions for advancement in the field of solid-state lighting. Challenges faced by Light emitting diodes for maintaining color and visual comfort are also illustrated. Failure modes and environmental impact of light emitting diodes are also analysed. Quantum dot based solid state lightening is also presented to study the chromatic characteristics.  Some critical factors of concern for broader application of light emitting diodes and additional enhancements in electrical, optical, temperature characteristic, high power output and color furnishing capabilities are also demonstrated in paper. Light emitting diodes wattage output and efficiency are also discussed for practical viability of solid state devices in emerging fields. The extension lead of current LED technology in evolving applications are considered as accumulation of numerous technologies such as wireless, communication, sensors and control engineering. Undoubtedly, LED engineering is contemporary and the price maybe unreasonable. Nevertheless, it will find its usage in very nearly all applications and the initiation of new techniques that might lessen the cost.

A. Grozdanov, P. Paunović, Violeta Vasilevska-Nikodinovska et al.

Emerging nanotechnologies in which nuclear applications and radiations play key roles are: nano-electronics in environmental monitoring and remediation, electrode materials in hydrogen economy, polymer based nanocomposites in biotechnology, diagnostics and therapy. Radiation based technology using x-rays, e-beams and ion-beams is the key to avariety of different approaches. Due to the various ionizing irradiations, physical, chemical and biological properties of the materials can be significantly modified. Compared with conventional chemical reduction, the irradiation techniques are environmentally friendly, easily controlled, highly pure and less destructive. The most common defects induced by irradiation are vacancies and interstitials. Carbon based nanostructures with sp2-like hybridization, are exclusive due to the fact that its valence permitted researchers to engineer a large collection of molecular architectures. What makes all these structures truly phenomenal is that they are indeed built from the same component and they still can differ in shape and dimensionality. The most prolific irradiation-induced defects in graphenic carbon nanostructures are vacancies (single or multi vacancies). These carbon sp2nanostrucutres develop an extended reconstruction of the atomic network near the vacancy by saturating two dangling bonds and forming a pentagon. In graphene, single vacancies reconstruct, but in CNT the reconstruction is much stronger owing to the curvature and inherent nanoscale size of the system. It was found that for a CNTs to contract locally to “heal” the hole and thus saturate energetically unfavorable danging bonds. Thus, curved graphitic structures such as CNTs can be referred to as self-healing materials under irradiation. Some of the last experimental studies on the irradiation of MWCNTs reported a broad range of interesting phenomena such as surface reconstructions, modified mechanical properties, ion-irradiation induced changes in electrical coupling between nanotubes.1-3 Kis et al., have shown a strong stiffening of bundles of CNTs after electron irradiation.4 Last years, irradiation with γ-rays was studied as one of the clean and easy method for modification of carbon nanostructures. Namely, the effects of γ-irradiation strongly depend on the irradiation conditions, the materials type and the irradiation medium. Guo et al. observed a dramatic increase in the ID/IG of the Raman spectrum of γ-ray irradiated multi-walled CNTs (MWCNTs), which was attributed to the large presence of sp3-hybridized carbon atoms.5 This is opposite to the trend reported by Xu et al.,6 who noted an 8% decrease in ID/ IG for MWCNTs irradiated to 20Mrad in air, signaling improved graphitic order.6 Also, it was found that γ-irradiation decreased the diameter of MWCNTs, increased their specific surface area and modified their oxygen functional groups.7 The graphitization of MWCNTs was improved with doses of 100kGy, while a higher dose of 150kGy induced structural damage.7 Regarding the graphene, γ-irradiation was used for the reduction of graphene oxide in different liquid media.8 Bardi et al.,9 studied x-ray irradiation induced structural changes on single wall carbon nanotubes.9 Based on the Raman and XPS measurements, they confirmed the modifications in the structure of the nanotube surfaces, and found that the degree of disorder in the CNTs structure correlates with the x-ray irradiation dose.9 Although a huge amount of theoretical works were done to understand the origin of various kinds of irradiated induced structural changes and defects in carbon nanostructures, very little is known experimentally. Thus, the present work is aimed to focus on the influence of X-ray irradiation on the structural identification of changes and defects formed in carbon based nanostructures (G, MWCNTs, hybrid G/MWCNTs).

T. Tanitteerapan, Sunisa Lakham

To make understanding for young electrical technologist who has to solve the harmonic current problems and design solution in the future, the power harmonic solution contents should be set to power electronics course for undergraduate electrical engineering study. This paper, design of experimental learning module on passive harmonic filter for variable speed drive was proposed. The proposed learning module was consisted of experimental module and laboratory sheets and they were designed for using as experimental learning module on harmonic current filtering method by passive filter that designed for installing at the front end of variable speed drive (VSD). T connected Inductor – Capacitor –Inductor (LCL) Filter was selected and designed to set as experimental module based on experimental topic, and objective analysis. With and without filter for VSD conditions were set up in the proposed learning module. Two laboratory sheets were designed following learning objectives. Circuit experimentation of 1 kW of VSD typed passive filter were applied to verify the proposed module. As results, input current behaviors of filter installed system were clearly following theory, implying the proposed module can make understanding for undergraduate students.

P. G. Lasy, I. Meleshko

The paper deals with a mixed problem for the telegraph equation well-known in electrical engineering and electronics, provided that the line is free from distortion. This problem is reduced to the analogous one for the one-dimensional inhomogeneous wave equation. Its solution can be found as the sum of the solution for a mixed homogeneous boundary value problem for the corresponding homogeneous wave equation and for the solution of a non-homogeneous wave equation with homogeneous boundary data and zero initial conditions. Solutions to both problems can be found by separating the variables in the form of a series of trigonometric functions of the line point with time-dependent coefficients. Such solutions are inconvenient for real application because they require calculation of a large number of integrals, and it is difficult to estimate the miscalculation. An alternative method for solving this problem is proposed, based on the use of special functions, viz. polylogarithms, which are complex power-series with power coefficients converging in a unit circle. The exact solution of the problem is expressed in the integral form via the imaginary part of the first-order polylogarithm on the unit circle, and the approximate one is expressed in the form of a finite sum via the real part of the dilogarithm and the imaginary part of the third-order polylogarithm. All these parts of the polylogarithms are periodic functions that have polynomial expressions of the corresponding powers on the segment of the length equal to the period. This makes it possible to effectively find an approximate solution to the problem. Also, a simple and convenient error estimate of the approximate solution of the problem is found. It is linear with respect to the step of splitting the line and the step of splitting the time range in which the problem is considered. The score is uniform along the length of the line at each fixed point of time. A concrete example of solving the problem according to the proposed mode is presented; graphs of exact and approximate solutions are constructed.

Zhenxue He, Limin Xiao, Zhisheng Huo et al.

Logic minimization has recently attracted significant attention because in many applications it is important to have a compact representation as possible. In this paper, we propose a fast minimization algorithm (FMA) of fixed polarity Reed-Muller expressions (FPRMs). The main idea behind the FMA is to search the minimum FPRM with the fewest products by using the proposed binary differential evolution algorithm (BDE). The BDE can efficiently maintain population diversity and achieve a better tradeoff between the exploration and exploitation capabilities by use of proposed binary random mutation operator and improved selection operator. The experimental results on 24 MCNC benchmark circuits demonstrate that the FMA outperforms the genetic algorithm-based and simulated annealing genetic algorithm-based FPRMs minimization algorithms in terms of accuracy of solutions and solving efficiency. To the best of our knowledge, we are the first to use differential evolution algorithm to minimize FPRMs. The FMA can be extended to derive a minimum mixed polarity Reed-Muller expression.

Efrén Wilfrido Ortiz, Geovanna Madero, Paulina Lima

Esta investigación presenta una alternativa para la fabricación de tuberías de alcantarillado en base a material reciclado de la ciudad de Quito. Se sustenta la calidad de las tuberías fabricadas con polietileno de alta densidad (PEAD) reciclado mediante los ensayos para tuberías de alcantarillado: densidad, rigidez anular, aplastamiento entre placas, resistencia al impacto, transferencia de sustancias contaminantes desde el tubo hacia el agua que circula por la tubería y agrietamiento por estrés ambiental, los cuales fueron hechos para diferentes proporciones entre material reciclado y material virgen.

M. Lupberger, Freddy Fuentes Robayo, Y. Huang et al.

Michael Lupberger*† CERN, Geneva, Switzerland E-mail: michael.lupberger@cern.ch Freddy Fuentes Robayo Universidad Antonio Narino, Bogota, Columbia Yan Huang Central China Normal University, Wuhan, China Sorin Martoiu Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Bucharest, Romania Hans Müller CERN, Geneva, Switzerland Dorothea Pfeiffer CERN, Geneva, Switzerland and European Spallation Source ERIC, Lund, Sweden Alexandru Rusu Horia Hulubei National Institute of Physics and Nuclear Engineering, Magurele, Bucharest, Romania The Scalable Readout System (SRS) of the RD51 collaboration with the APV25 ASIC is driving R&D for gaseous detectors. Discontinuation of APV25 and demands on flexibility concerning e.g. detector capacitance and readout rate induced a replacement of the ASIC, for which the collaboration has chosen the VMM chip of the ATLAS New Small Wheel upgrade. A prototype SRS VMM system was operated with small GEM detectors at test beams and hardware components are finalised. More than twelve groups signed as primary system users. We present the readout chain and current status of the implementation of the VMM in SRS, applications and further developments. Topical Workshop on Electronics for Particle Physics (TWEPP2018) 17-21 September 2018 Antwerp, Belgium