scholarly journals Taming the Electromagnetic Boundaries via Metasurfaces: From Theory and Fabrication to Functional Devices

2015 ◽  
Vol 2015 ◽  
pp. 1-80 ◽  
Author(s):  
Xiangang Luo ◽  
Mingbo Pu ◽  
Xiaoliang Ma ◽  
Xiong Li
Keyword(s):  
Electromagnetic Waves ◽  
Low Cost ◽  
Polarization State ◽  
Three Dimensional ◽  
Current Status ◽  
Future Trends ◽  
State Control ◽  
The World ◽  
Response Phase ◽  
High Degree

As two-dimensional metamaterials, metasurfaces have received rapidly increasing attention from researchers all over the world. Unlike three-dimensional metamaterials, metasurfaces can be utilized to control the electromagnetic waves within one infinitely thin layer, permitting substantial advantages, such as easy fabrication, low cost, and high degree of integration. This paper reviews the history and recent development of metasurfaces, with particular emphasis on the theory and applications relating to the frequency response, phase shift, and polarization state control. Based on the current status of various applications, the challenges and future trends of metasurfaces are discussed.

The sustainability of fresh groundwater resources in major deltas around the world

2021 ◽  
Author(s):  
Joeri van Engelen ◽  
Gualbert Oude Essink ◽  
Marc Bierkens
Keyword(s):  
Sea Water ◽  
Salt Water ◽  
Groundwater Resources ◽  
Three Dimensional ◽  
Variable Density ◽  
Current Status ◽  
Irrigated Agriculture ◽  
Fresh Groundwater ◽  
Precise Knowledge ◽  
The World

<p>Increasing population, growth of cities and intensifying irrigated agriculture in the world’s deltas promote the demand for fresh water resources, accelerating groundwater extraction. This, in turn, leads to sea water intrusion and salt water upconing, which threaten near-future water and food security. Proper water management in deltas requires precise knowledge about the current status of the deltas’ fresh groundwater resources, in the form of a groundwater salinity distribution. However, this knowledge is scarcely present, especially at larger depths. In this research, we applied three-dimensional variable-density groundwater model simulations over the last 125 ka to estimate present-day fresh groundwater volumes for several major deltas around the world. We also compared these to current extraction rates and estimated the time until in-situ fresh groundwater resources are completely exhausted (ignoring local-scale problems), partly leading to groundwater level decline and mostly replacement with river water or saline groundwater. In this presentation we will share our findings, for example which deltas’ groundwater reserves presumably are under stress.</p>

scholarly journals Graded metascreens to enable a new degree of nanoscale light management

2015 ◽  
Vol 373 (2049) ◽  
pp. 20140351 ◽  
Author(s):  
Nasim Mohammadi Estakhri ◽  
Christos Argyropoulos ◽  
Andrea Alù
Keyword(s):  
Electromagnetic Waves ◽  
Polarization State ◽  
Three Dimensional ◽  
Single Layer ◽  
Absorption Enhancement ◽  
Management Technique ◽  
Optical Waves ◽  
Novel Approach ◽  
Local Wave ◽  
Light Management

Optical metasurfaces, typically referred to as two-dimensional metamaterials, are arrays of engineered subwavelength inclusions suitably designed to tailor the light properties, including amplitude, phase and polarization state, over deeply subwavelength scales. By exploiting anomalous localized interactions of surface elements with optical waves, metasurfaces can go beyond the functionalities offered by conventional diffractive optical gratings. The innate simplicity of implementation and the distinct underlying physics of their wave–matter interaction distinguish metasurfaces from three-dimensional metamaterials and provide a valuable means of moulding optical waves in the desired manner. Here, we introduce a general approach based on the electromagnetic equivalence principle to develop and synthesize graded, non-periodic metasurfaces to generate arbitrarily prescribed distributions of electromagnetic waves. Graded metasurfaces are realized with a single layer of spatially modulated, electrically polarizable nanoparticles, tailoring the scattering response of the surface with nanoscale resolutions. We discuss promising applications based on the proposed local wave management technique, including the design of ultrathin optical carpet cloaks, alignment-free polarization beam splitters and a novel approach to enable broadband light absorption enhancement in thin-film solar cells. This concept opens up a practical route towards efficient planarized optical structures with potential impact on the integrated nanophotonic technology.

scholarly journals The Costs of Producing Biodiesel from Microalgae in the Asia-Pacific Region

2013 ◽  
Vol 2 (3) ◽  
pp. 105-113 ◽  
Author(s):  
G.J. Griffin ◽  
D.F. Batten ◽  
T. Beer ◽  
P.K. Campbell
Keyword(s):  
Low Cost ◽  
Operating Cost ◽  
Asia Pacific ◽  
Pacific Region ◽  
Asia Pacific Region ◽  
Cost Estimates ◽  
The World ◽  
Resource Availability Cost ◽  
The Cost ◽  
High Degree

Capital and operating cost estimates for converting microalgae to oil or biodiesel are compared. These cost comparisons are based on Australian locations, which are expected to fall at the lower end of the cost spectrum in the Asia-Pacific Region and other parts of the world.  It is assumed that microalgae are grown in a concentrated saltwater medium in raceway ponds, then are harvested, dewatered and the oil is extracted and converted to biodiesel by transesterification. The size of the desired pond system affects the number of potential locations due to constraints in resource availability. Cost estimates vary significantly due to differences in the assumed oil productivity, the harvesting equipment and the method of converting residual biomass to electric power. A comparison is made with recent cost estimates from other parts of the world, in which the expected costs of microalgae oil production from a number of publicly available sources lay between 0.34–31.0 USD/L.  The resulting cost estimates of between 1.37—2.66 USD/L are at the lower end of this scale, thereby confirming that Australia has the potential to be a low-cost producer of algal oil and biodiesel in the Asia-Pacific Region.  It was significant that, despite similar assumptions for the microalgae-to-oil process, cost estimates for the final biodiesel or oil price differed by a factor of 2.  This highlights the high degree of uncertainty in such economic predictions. Keywords: Asia-Pacific region; biodiesel; economics; microalgaeThis article is cited as :Griffin, G., Batten, D., Beer, T., & Campbell, P. (2013). The Costs of Producing Biodiesel from Microalgae in the Asia-Pacific Region. International Journal Of Renewable Energy Development (IJRED), 2(3), 105-113. doi:10.14710/ijred.2.3.105-113Permalinkhttp://dx.doi.org/10.14710/ijred.2.3.105-113

The Cave-let: A low-cost projective immersive display

2000 ◽  
Vol 6 (2_suppl) ◽  
pp. 24-26 ◽  
Author(s):  
Mark Green ◽  
Lloyd White
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Collaborative Systems ◽  
Design And Implementation ◽  
Wide Range ◽  
The World ◽  
Order Of Magnitude

This paper describes the design and implementation of a low-cost projective immersive display (PID), called the Cave-let. A PID immerses the user in a computer-generated three-dimensional environment that responds to the user's movements. Current devices of this nature are very expensive, so that fewer than 100 units have been installed around the world. A low-cost PID will enable a wide range of applications in areas such as telehealth, visualization, education and collaborative systems. To produce a low-cost PID, we identified the components of the design that represented the major costs. These were then redesigned with the aim of reducing cost as much as possible while preserving most of the functionality. The resulting device is suitable for a wide range of applications and is an order of magnitude less expensive than similar devices.

scholarly journals A Short Review of Benefits of Using Chest CT Characteristics for Early diagnoses to Corona Virus Disease 2019 (COVID-19)

2020 ◽  
pp. 1-6
Author(s):  
R. Vennila ◽  
R. Vennila ◽  
P. Venkatraman
Keyword(s):  
Computed Tomography ◽  
Virus Disease ◽  
Imaging Modality ◽  
Low Cost ◽  
Three Dimensional ◽  
Short Review ◽  
Developed Countries ◽  
Rt Pcr ◽  
Corona Virus ◽  
The World

In 21st century, the year 2020 was expected with much development in India as well many other countries. But unfortunately, the world is facing many natural calamities. World is taking steps towards rescue mission of the disasters. Among of those calamities, deadly Corona Virus remains still all over the world as pandemic disease. Even the developed countries are struggling to come back to its normal routine. India is a country with developing technologies. Vaccines are yet to be developed for treatment of this Novel Corona Virus. As a diagnostic tool, Nasopharyngeal and Oropharyngeal swabs are taken from the person and tested using RT-PCR. This test is not 100 percent accurate. Confirmed COVID patients after few days are undergoing the medical imaging. This diagnostic imaging technique helps in showing the progression of this virus spread in Upper and Lower respiratory system. Chest Radiography is low cost modality but its sensitivity towards observation is 69%. Lung Ultrasound is used in Intensive Care patients and not used for routine diagnosing purpose. Computed Tomography plays a crucial role in three-dimensional chest imaging of COVID-19 patients. The sensitivity of CT is 98%. The aim of this paper is to consider CT as a tool for diagnosing COVID-19 patient than using the standard tool RT-PCR. A brief knowledge about imaging modality like X-ray, Ultrasound and Computed Tomography when used against COVID patient is explained. This paper gives reason for the ideal use of CT diagnosis for COVID 19.

Study on Current Status and Future Developments in Nuclear-Power Industry of the World

2018 ◽  
Author(s):  
R. Pioro ◽  
A. Zvorykin ◽  
R. Machrafi ◽  
I. Pioro
Keyword(s):  
Nuclear Power ◽  
Power Industry ◽  
Nuclear Power Industry ◽  
Current Paper ◽  
Severe Accident ◽  
Current Status ◽  
Future Trends ◽  
Nuclear Power Reactor ◽  
Future Developments ◽  
The World

Currently, nuclear power plays a quite visible role in the world electricity generation (∼11%). However, before the Fukushima Nuclear Power Plant (NPP) severe accident in March of 2011, NPPs generated about 14% of the world’s electricity. Accounting that after, mainly, Chernobyl NPP severe accident a number of power reactors built and put into operation in the world decreased from 120 within 1985–1990 to about 22 per 5 years (within 1995–2015), we might face a significant shortage of operating power reactors within 2030–2040. Therefore, it is important to evaluate current status of nuclear-power industry and to make projections on near (5–10 years) and far away (10–25 years and beyond) future trends in nuclear-power industry. In the current paper statistics on all current nuclear-power reactors were analyzed and based on that future trends were estimated in terms of types of reactors to be left after 10 years, new types of reactors to be put into operation, projections of how many reactors and of which types will be build. To make any projections an average operating term of power reactors should be estimated. In the current paper a nuclear-power-reactor operating term of 45 years was considered. Also, rates of building and putting into operation power reactors worldwide were estimated, and several scenarios of future developments in nuclear-power industry in the world and in selected countries were considered.

scholarly journals Generation of Beam Tilt through Three-Dimensional Printed Surface

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3174
Author(s):  
Sujan Shrestha ◽  
Hijab Zahra ◽  
Syed Muzahir Abbas ◽  
Arslan Kiyani ◽  
Bahare Mohamadzade ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Low Cost ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Operating Frequency Range ◽  
Input Source ◽  
3D Printed ◽  
Ku Band

In this paper, 3D printed surfaces are presented to study this technology’s application in generating beam tilt for the electromagnetic waves in the Ku-band. Additionally, the input source is maintained by a feed horn that is additively manufactured and is coated with copper spray paint to add conductivity, which is fed by a WR-75 waveguide. The proposed beam tilt generating surface is also referred to as a Beam Deviating Surface (BDS). There is no relative gap between the BDS and the aperture of the horn, which eventually decreased the overall antenna height. The BDS layer is able to deviate the beam for a fixed elevation angle of 22.5∘ and could be consequently rotated along with the rotation of the BDS prototype. The voltage standing wave ratio value is less than two over the operating frequency range, which depicts the wideband behavior. The measured and simulated radiation patterns show that we can tilt the electromagnetic waves in ranges of up to +/−22.5∘ with a minimum side lobe level of −5 dB at frequencies from 10 to 15 GHz. This signifies the wideband characteristic of the proposed prototype, which is achieved by Vero material from Multijet Printing that is a low-cost and rapid manufacturing 3D printing technology.

IOT Technology, Applications, and Challenges

2020 ◽  
pp. 65-113
Author(s):  
Asha Gowda Karegowda ◽  
Devika G. ◽  
Ramya Shree T. P.
Keyword(s):  
Operating Systems ◽  
Low Cost ◽  
Research Work ◽  
Vital Role ◽  
Future Trends ◽  
Systems Architecture ◽  
The World ◽  
Technology Applications ◽  
Almost All ◽  
Exchange Data

The world we in is virtually becoming smaller since living and nonliving things are connected to the internet. Internet of things, or IoT, is a system of interconnected things, each with unique identifiers (UIDs) and the ability to exchange data without the need of human intervention. The rapid growth of IoT is considered the next wave for enhancing services in almost all sectors of life, at low cost and time. This chapter presents IoT in a broader context, in terms of its growth, IoT operating systems, architecture, and future trends of IoT. The major contribution is detailed information of umpteen IoT applications. The various benefits of IoT, matter of concerns with respect to IoT, scope of research work are also discussed. The integration of various technologies is the main enabling factor of IoT, yielding more benefits to society as a whole. Also, supports in understanding implementation technologies and the major applications of their domain where IoT plays a vital role and future problems for next 20 years are also explicated.

Numerical Analysis on the Radiant Characteristics of Three-Dimensional Random Rough Surfaces

2009 ◽  
Author(s):  
Yanhui Feng ◽  
Wei Liu ◽  
Xinxin Zhang
Keyword(s):  
Electromagnetic Waves ◽  
Rough Surfaces ◽  
Polarization State ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Simulation Method ◽  
Scattering Angle ◽  
Scattering Intensity ◽  
Random Rough Surfaces ◽  
Shadowing Effect

In the area of micro- and nano-scale radiation heat transfer, the radiant characteristics of rough surfaces have drawn increasing attention. In this paper, three-dimensional Gaussian random rough surfaces were created by the Monte Carlo simulation method. Ray tracing method combined with the Kirchhoff approximation was employed to analyze the shadowing effect of random surfaces with different roughness. The relative scattering intensity from rough surfaces was further investigated by the Fresnel law. The results indicated that the peak of the relative scattering intensity occurred at the anti-scattering angle and the scattering distributions were continuous. With increasing surface roughness, the height of the peak became lower, the width of distribution became wider, and the distribution range of the scattering angle and the azimuth of the reflection electromagnetic waves increased. Furthermore, the relative scattering intensity concentrated in the vicinity of the anti-scattering angle and the largest scattering intensity occurred in the specular direction. Taking into account of the effects of polarization state and wavelength of incidence waves, it was shown that the relative scattering intensity of s polarized incident wave was slightly larger than that of p polarization, while the relative scattering intensity became stronger as the wavelength increased.

Sign in / Sign up

Export Citation Format

Share Document