scholarly journals Recent Developments and State of the Art in Flexible and Conformal Reconfigurable Antennas

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1375
Author(s):  
Bahare Mohamadzade ◽  
Roy B. V. B. Simorangkir ◽  
Sasa Maric ◽  
Ali Lalbakhsh ◽  
Karu P. Esselle ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
State Of The Art ◽  
Reconfigurable Antennas ◽  
Future Research ◽  
Electronic Systems ◽  
Frequency Pattern ◽  
Conformal Antennas ◽  
Recent Developments ◽  
Space Requirements

Reconfigurable antennas have gained tremendous interest owing to their multifunctional capabilities while adhering to minimalistic space requirements in ever-shrinking electronics platforms and devices. A stark increase in demand for flexible and conformal antennas in modern and emerging unobtrusive and space-limited electronic systems has led to the development of the flexible and conformal reconfigurable antennas era. Flexible and conformal antennas rely on non-conventional materials and realization approaches, and thus, despite the mature knowledge available for rigid reconfigurable antennas, conventional reconfigurable techniques are not translated to a flexible domain in a straight forward manner. There are notable challenges associated with integration of reconfiguration elements such as switches, mechanical stability of the overall reconfigurable antenna, and the electronic robustness of the resulting devices when exposed to folding of sustained bending operations. This paper reviews various approaches demonstrated thus far, to realize flexible reconfigurable antennas, categorizing them on the basis of reconfiguration attributes, i.e., frequency, pattern, polarization, or a combination of these characteristics. The challenges associated with development and characterization of flexible and conformal reconfigurable antennas, the strengths and limitations of available methods are reviewed considering the progress in recent years, and open challenges for the future research are identified.

Status of Centrifugal Impeller Internal Aerodynamics—Part II: Experiments and Influence of Viscosity

1980 ◽  
Vol 102 (3) ◽  
pp. 738-746 ◽  
Author(s):  
D. Adler
Keyword(s):  
Viscous Flow ◽  
Experimental Work ◽  
State Of The Art ◽  
Centrifugal Impeller ◽  
Future Research ◽  
Research Topics ◽  
Flow Problems ◽  
Recent Developments ◽  
Internal Aerodynamics ◽  
The Subject

Recent developments in internal viscous aerodynamics of centrifugal impellers and related flows are critically reviewed. The overall picture which emerges provides the reader with a state-of-the-art perspective on the subject. Gaps in understanding are identified to stimulate future research. Topics included in this review are: experimental work carried out in the last decade, the structure of turbulence in curved rotating passages and solution of viscous flow problems in impellers.

scholarly journals EEG-Based Emotion Recognition: A State-of-the-Art Review of Current Trends and Opportunities

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Nazmi Sofian Suhaimi ◽  
James Mountstephens ◽  
Jason Teo
Keyword(s):  
Emotion Recognition ◽  
State Of The Art ◽  
Research Community ◽  
Human Interaction ◽  
Human Cognition ◽  
Future Research ◽  
Emotional States ◽  
Human Beings ◽  
Eeg Signals ◽  
Recent Developments

Emotions are fundamental for human beings and play an important role in human cognition. Emotion is commonly associated with logical decision making, perception, human interaction, and to a certain extent, human intelligence itself. With the growing interest of the research community towards establishing some meaningful “emotional” interactions between humans and computers, the need for reliable and deployable solutions for the identification of human emotional states is required. Recent developments in using electroencephalography (EEG) for emotion recognition have garnered strong interest from the research community as the latest developments in consumer-grade wearable EEG solutions can provide a cheap, portable, and simple solution for identifying emotions. Since the last comprehensive review was conducted back from the years 2009 to 2016, this paper will update on the current progress of emotion recognition using EEG signals from 2016 to 2019. The focus on this state-of-the-art review focuses on the elements of emotion stimuli type and presentation approach, study size, EEG hardware, machine learning classifiers, and classification approach. From this state-of-the-art review, we suggest several future research opportunities including proposing a different approach in presenting the stimuli in the form of virtual reality (VR). To this end, an additional section devoted specifically to reviewing only VR studies within this research domain is presented as the motivation for this proposed new approach using VR as the stimuli presentation device. This review paper is intended to be useful for the research community working on emotion recognition using EEG signals as well as for those who are venturing into this field of research.

scholarly journals MXD6 in film manufacturing: State of the art and recent advances in the synthesis and characterization of new copolyamides

2019 ◽  
Vol 36 (1) ◽  
pp. 16-37
Author(s):  
Micaela Vannini ◽  
Paola Marchese ◽  
Annamaria Celli ◽  
Cesare Lorenzetti
Keyword(s):  
Chemical Resistance ◽  
State Of The Art ◽  
Large Family ◽  
Isophthalic Acid ◽  
Future Perspectives ◽  
Gas Barrier ◽  
Structures And Properties ◽  
Recent Developments ◽  
Order Of Magnitude

Semiaromatic polyamides belong to a large family of polymers commonly utilized in demanding engineering applications due to a unique set of outstanding mechanical properties as well as in terms of thermal and chemical resistance. Somewhat less understood is the use of certain members of this family in packaging applications such as the manufacturing of films and sheets or thin-walled containers, as well as the motivations and limitations in designing film structures containing them. This article reviews how m-xylylene diamine (MXD)-based polyamides are used in packaging applications. Attention is also given to film manufacturing and criticalities in its processing. Recent developments in MXD-based polyamides for gas barrier applications are also reported, while examining future perspectives in speciality film manufacturing. The new described copolymers based on MXD6 were synthesized by introducing different co-units, like isophthalic acid, 2,6-naphthalenedicarboxylic acid, glutaric acid, oxalic acid or 1,6-hexamethylene diamine. The performed characterization analyses (DMTA, DSC, density and OTR) allowed the polymer structures and properties to be correlated. Introducing 2,6-naphthalenedicarboxylic acid along the MXD6 chain led to the highest Tg (101°C) and density (1.233 g/cm3) and the lowest OTR (0.0035 cm3·cm/m2·day·atm, up to one order of magnitude lower).

scholarly journals State of the Art in Alcohol Sensing with 2D Materials

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ramin Boroujerdi ◽  
Amor Abdelkader ◽  
Richard Paul
Keyword(s):  
State Of The Art ◽  
2D Materials ◽  
Chemical Species ◽  
Weight Ratio ◽  
Layered Compounds ◽  
Single Atom ◽  
Future Research ◽  
Essential Factor ◽  
New Materials ◽  
Recent Developments

AbstractSince the discovery of graphene, the star among new materials, there has been a surge of attention focused on the monatomic and monomolecular sheets which can be obtained by exfoliation of layered compounds. Such materials are known as two-dimensional (2D) materials and offer enormous versatility and potential. The ultimate single atom, or molecule, thickness of the 2D materials sheets provides the highest surface to weight ratio of all the nanomaterials, which opens the door to the design of more sensitive and reliable chemical sensors. The variety of properties and the possibility of tuning the chemical and surface properties of the 2D materials increase their potential as selective sensors, targeting chemical species that were previously difficult to detect. The planar structure and the mechanical flexibility of the sheets allow new sensor designs and put 2D materials at the forefront of all the candidates for wearable applications. When developing sensors for alcohol, the response time is an essential factor for many industrial and forensic applications, particularly when it comes to hand-held devices. Here, we review recent developments in the applications of 2D materials in sensing alcohols along with a study on parameters that affect the sensing capabilities. The review also discusses the strategies used to develop the sensor along with their mechanisms of sensing and provides a critique of the current limitations of 2D materials-based alcohol sensors and an outlook for the future research required to overcome the challenges.

Toward a Characterization of Adaptive Systems

2012 ◽  
Vol 54 (6) ◽  
pp. 1008-1024 ◽  
Author(s):  
Karen M. Feigh ◽  
Michael C. Dorneich ◽  
Caroline C. Hayes
Keyword(s):  
Adaptive Systems ◽  
Future Research ◽  
Cognitive State ◽  
Research Issues ◽  
Systems Research ◽  
Recent Developments ◽  
Current Context ◽  
Physiological Sensors ◽  
Trigger Mechanisms

Objective: This article presents a systematic framework characterizing adaptive systems. Background: Adaptive systems are those that can appropriately modify their behavior to fit the current context. This concept is appealing because it offers the possibility of creating computer assistants that behave like good human assistants who can provide what is needed without being asked. However, the majority of adaptive systems have been experimental rather than practical because of the technical challenges in accurately perceiving and interpreting users’ current cognitive state; integrating cognitive state, environment, and task information; and using it to predict users’ current needs. The authors anticipate that recent developments in neurological and physiological sensors to identify users’ cognitive state will increase interest in adaptive systems research and practice over the next few years. Method: To inform future efforts in adaptive sys-tems, this work provides an organizing framework for characterizing adaptive systems, identifying consider-ations and implications, and suggesting future research issues. Results: A two-part framework is presented that (a) categorizes ways in which adaptive systems can modify their behavior and (b) characterizes trigger mechanisms through which adaptive systems can sense the current situation and decide how to adapt. Conclusion: The framework provided in this article provides a tool for organizing and informing past, present, and future research and development efforts in adaptive systems.

scholarly journals Liquid-Based Reconfigurable Antenna Technology: Recent Developments, Challenges and Future

2020 ◽  
Author(s):  
Habshah Abu Bakar ◽  
Rosemizi Abd Rahim ◽  
Ping Jack Soh ◽  
Prayoot Akkaraekthalin
Keyword(s):  
High Frequency ◽  
Communication Systems ◽  
Room Temperature ◽  
State Of The Art ◽  
Reconfigurable Antennas ◽  
Wireless Communication Systems ◽  
Dielectric Resonators ◽  
Different Types ◽  
Recent Developments ◽  
Basic Approaches

Advances in reconfigurable liquid-based reconfigurable antennas are enabling new possibilities to fulfil the requirements of more advanced wireless communication systems. In this review, a comparative analysis of various state-of-the-art concepts and techniques for designing reconfigurable antennas using liquid is presented. First, the electrical properties of different liquids at room temperature commonly used in reconfigurable antennas are identified. This is followed by a discussion of various liquid actuation techniques in enabling high frequency reconfigurability. Next, liquid-based reconfigurable antennas in literature used to achieve the different types of reconfiguration will be critically reviewed. These include frequency-, polarization-, radiation pattern- and compound reconfigurability. The current concepts of liquid-based reconfigurable antennas can be classified broadly into three basic approaches: altering the physical (and electrical) dimensions of antennas using liquid, applying liquid-based sections as reactive loads; and implementation of liquids as dielectric resonators. Each concept and their design approaches will be examined, outlining their benefits, limitations, and possible future improvements.

scholarly journals Liquid-Based Reconfigurable Antenna Technology: Recent Developments, Challenges and Future

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 827
Author(s):  
Habshah Abu Bakar ◽  
Rosemizi Abd Rahim ◽  
Ping Jack Soh ◽  
Prayoot Akkaraekthalin
Keyword(s):  
High Frequency ◽  
Communication Systems ◽  
Room Temperature ◽  
State Of The Art ◽  
Reconfigurable Antennas ◽  
Wireless Communication Systems ◽  
Dielectric Resonators ◽  
Different Types ◽  
Recent Developments ◽  
Basic Approaches

Advances in reconfigurable liquid-based reconfigurable antennas are enabling new possibilities to fulfil the requirements of more advanced wireless communication systems. In this review, a comparative analysis of various state-of-the-art concepts and techniques for designing reconfigurable antennas using liquid is presented. First, the electrical properties of different liquids at room temperature commonly used in reconfigurable antennas are identified. This is followed by a discussion of various liquid actuation techniques in enabling high frequency reconfigurability. Next, the liquid-based reconfigurable antennas in literature used to achieve the different types of reconfiguration will be critically reviewed. These include frequency-, polarization-, radiation pattern-, and compound reconfigurability. The current concepts of liquid-based reconfigurable antennas can be classified broadly into three basic approaches: altering the physical (and electrical) dimensions of antennas using liquid; applying liquid-based sections as reactive loads; implementation of liquids as dielectric resonators. Each concept and their design approaches will be examined, outlining their benefits, limitations, and possible future improvements.

Education

2020 ◽  
pp. 534-549
Author(s):  
Theofanis Exadaktylos
Keyword(s):  
Higher Education ◽  
Financial Crisis ◽  
Policy Implementation ◽  
State Of The Art ◽  
Future Research ◽  
Policy Area ◽  
Political Debates ◽  
Recent Developments ◽  
New Curricula

The purpose of this chapter is to provide a ‘state of the art’ contribution about education in Greece, reviewing recent developments and reforms. As a policy area, education remains highly controversial in Greece from developing new curricula to the politicization of higher education. The chapter reflects on the pedagogical and political debates of the recent decades focusing on issues of policy implementation. It highlights the most recent round of reforms since 2011 including those resulting from the advent of Syriza to power, and looks at the period of the financial crisis to discuss issues of funding, the bailout agreements, and neoliberal ideas behind higher education. The chapter concludes by offering some suggestions for future research and sets out some of the respective challenges.

scholarly journals Perspectives on the future of multi-dimensional platforms

2019 ◽  
Vol 218 ◽  
pp. 72-100 ◽  
Author(s):  
Gino Groeneveld ◽  
Bob W. J. Pirok ◽  
Peter J. Schoenmakers
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
State Of The Art ◽  
Two Dimensional ◽  
Current State ◽  
Recent Developments ◽  
Resolution Mass

A practical example, the characterization of polysorbates by high-resolution comprehensive two-dimensional liquid chromatography in combination with high-resolution mass spectrometry, is described as a culmination of recent developments in 2D-LC and as an illustration of the current state of the art.

Trace element speciation in food: State of the art of analytical techniques and methods

2012 ◽  
Vol 84 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Rola Bou Khouzam ◽  
Joanna Szpunar ◽  
Michel Holeman ◽  
Ryszard Lobinski
Keyword(s):  
High Resolution Mass Spectrometry ◽  
State Of The Art ◽  
Analytical Techniques ◽  
Metal Species ◽  
Recent Developments ◽  
Food And Feed ◽  
Element Speciation ◽  
Analytical Approaches

Some elements in food are notoriously toxic, whereas others are considered essential for human health. Information on the exact chemical form in which an element is present in food is of paramount importance to determine the safety and nutritional quality of food. This critical review discusses the state of the art of analytical approaches to speciation of trace elements in food products. The topics addressed include (i) responding to regulations concerning some toxic elements (As, Hg, Sn); (ii) quality control of food and feed supplements; and (iii) characterization, in terms of element speciation, of nutritional plants (natural and genetically modified) and food supplements produced by biotechnology. The maturity of analytical techniques allowing the determination of individual well-defined metal species is highlighted. On the other hand, the recent developments of multidimensional hyphenated techniques and the democratization of electrospray high-resolution mass spectrometry (Orbitrap) start permitting fine characterization of element speciation in natural products.

Sign in / Sign up

Export Citation Format

Share Document