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Journal articles on the topic 'Radio via fibre optique'

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1

Treps, Nicolas. "De l’imagerie quantique aux télécommunications : une histoire de modes." Photoniques, no. 92 (July 2018): 25–28. http://dx.doi.org/10.1051/photon/20189225.

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Du fait de ses potentielles applications, la mise en forme spatiale de la lumière est une des problématiques d’optique les plus actives. Ses succès sont déjà multiples, que ce soit en astronomie ou imagerie biologique, via l’optique adaptative, ou encore pour la focalisation à travers des milieux diffusants. L’optique quantique aussi y a puisé de l’inspiration, pour permettre en particulier d’ordonner spatialement les fluctuations quantiques et réaliser des expériences de métrologie quantique. De manière remarquable, les procédés développés pour ces études fondamentales ont des applications en télécommunications par fibre optique et ont permis de fonder la société CAILabs.
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2

Vergniault, Christophe, Edouard Buchoud, Joséphine Boisson-Gaboriau, and Amélie Hallier. "Application des méthodes géophysiques pour le diagnostic de l’aléa cavités sur des ouvrages de grands linéaires, en contexte ferroviaire et hydraulique." Revue Française de Géotechnique, no. 172 (2022): 3. http://dx.doi.org/10.1051/geotech/2022006.

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Cet article traduit la volonté de deux maîtres d’ouvrages (ayant une compétence interne d’ingénierie conseils en géophysique), que sont SNCF Réseau et EDF, de mettre en commun leurs retours d’expériences pour améliorer la gestion des risques liés à l’aléa cavités souterraines sur des ouvrages de grands linéaires, en contexte ferroviaire ou hydraulique. Cette coopération a permis de valider plusieurs méthodes de diagnostic, par reconnaissance et auscultation, afin de détecter des cavités souterraines et de suivre leur évolution : dans deux contextes géologiques distincts (craie et marnes à gypse), les méthodes sismiques actives et passives basées sur les ondes de surface ont confirmé leurs performances théoriques, aussi bien pour des reconnaissances que de la surveillance en continu : (1) dans un contexte de cavités anthropiques dans la craie et hors nappe, les exemples présentés valident l’intérêt de certaines méthodes industrielles de reconnaissance (DCOS®, ParSeis®) et laissent espérer une industrialisation prochaine de plusieurs autres (SI active et passive), (2) dans le contexte de dissolution de gypse, ces mêmes méthodes utilisant le signal généré par les circulations ferroviaires se sont avérées très pertinentes pour assurer une surveillance en continu, via un monitoring 4D, du sol support de la plateforme ferroviaire. Le résultat de ce développement permettra de s’inscrire dans une démarche de maintenance prédictive vis-à-vis du risque fontis ; dans le contexte de dissolution de gypse, la mesure de déformation par fibre optique en place dans un remblai a démontré sa pertinence pour capter l’amorce de remontée d’un fontis, avant même l’apparition d’indice en surface. Enfin, il faut noter que les méthodes de reconnaissance et d’auscultation, présentées dans les deux premiers cas d’étude, pourraient favorablement être réalisées en utilisant une fibre optique comme celle exploitée dans le troisième cas d’étude, mais il faudrait un interrogateur optique différent de type DAS. Ceci est une perspective à laquelle s’intéressent les deux maîtres d’ouvrages.
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3

Sirgant, Aline, Stéphane Mottin, Raymond Cespuglio, Claude Pedri, and Pierre Laporte. "Mesure du NADH par microchip YAG triplé." J. Phys. IV Pr5-9 (May 1, 1999): 119–20. https://doi.org/10.5281/zenodo.439016.

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Nous présentons une instrumentation compacte, transportable, développé à l origine pour mesurer la fluorescence induite par laser du NADH cérébral chez l animal libre de ces mouvements. La source laser microchip Nd3+ : YAG est triplée en fréquence. Une fibre optique amène la lumière laser jusqu à la zone cible du cerveau et cette même fibre récupère la fluorescence de cette microzone (noyau du raphé dorsal). L acquisition de données se fait via un monochromateur suivi soit d un photomultiplicateur et d un Box-car soit d une caméra à balayage de fente. Les premières expériences réalisées sur un rat non anesthésié ou in vitro avec les deux systèmes d acquisition nous ont permis de vérifier que le niveau de fluorescence était suffisant pour être détecté. Les applications de ce capteur, développées actuellement, sont la détection des effets de certains médicaments au niveau du système nerveux central, l analyse des variations du NADH lors de l alternance des états de vigilance, ainsi qu une étude de l épilepsie.
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4

Watkins, S. "Development of a micro air vehicle." Aeronautical Journal 107, no. 1068 (2003): 117–23. http://dx.doi.org/10.1017/s0001924000018406.

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AbstractThe aerodynamic characteristics of five planar flying wing plan-forms suitable for micro air vehicles (MAVs) are investigated via a series of wind-tunnel tests. The external boundary of the five plan-forms result from slender carbon fibre (CF) struts under various degrees of buckling. The maximum lift/drag ratios were similar for all the (quite different) shapes but the stall characteristics were found to be markedly different. Results are presented of cross-plane traverses detailing the wake vector field and turbulence characteristics for two of the planforms at conditions close to stall. A MAV, based on mylar-covered buckled CF struts, is described. The MAV utilises elevon control based on modified commercially available micro radio control systems.
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5

Nugroho, Endang Retno, and Rianto Nugroho. "Perancangan Sistem Komunikasi Kabel Laut (SKKL) Fiber Optik Link Surabaya-Bawean." Jurnal Ilmiah Giga 25, no. 1 (2022): 28. http://dx.doi.org/10.47313/jig.v25i1.1663.

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<p><strong>Abstract</strong>. Internet network is an important requirement in the digital era. Indonesia is listed as the country with the highest data traffic growth in the world in 2016. To meet the needs of this data traffic, network access is needed. Indonesia has a geography that mostly covers the ocean. The islands lined up from Sabang to Merauke up to tens of thousands. This large number of islands is a problem in building communication infrastructure. Bawean Island is one of the islands in Indonesia with an area of 197 km2 with a population of more than 100,000 people in 2021. The pre-existing communication access is communication with VSAT using Satellite and Radio Wave Communication. Both types of communication have limitations in bandwidth capacity. In this research, it is proposed to design a Marine Cable Communication System (SKKL) for data access on Bawean Island. Data traffic is sent via optical fibre from the city of Surabaya to the island of Bawean which is 235 km away. In this design, we use a single-mode G.655 cable type and 5 optical amplifiers of the EDFA type. The results of the design show that the power link budget is -9.525 dBm, SNR 25.35 dB, Q-factor 9.26, and BER 1.009×10^-20.</p><p> </p><p><strong>Abstrak</strong>. Jaringan internet merupakan suatu kebutuhan penting di era digital. Indonesia tercatat sebagai negara dengan pertumbuhan trafik data tertinggi di dunia pada 2016. Untuk pemenuhan kebutuhan trafik data ini dibutuhkan akses jaringan. Indonesia memiliki geografis yang sebagian besar meliputi lautan. Pulau-pulau berjajar dari Sabang sampai Merauke jumlahnya hingga puluhan ribu. Jumlah pulau yang banyak inilah yang menjadi permasalahan dalam membangun infrastruktur komunikasi. Pulau Bawean adalah salah satu pulau di Indonesia dengan luas 197 km2 dengan penduduk lebih dari 100.000 jiwa pada tahun 2021. Akses komunikasi yang sudah ada sebelumnya adalah komunikasi dengan VSAT yang memanfaatkan Satelit dan Komunikasi Gelombang Radio. Kedua jenis komunikasi ini memiliki keterbatasan dalam kapasitas bandwidth. Dalam penelitian ini diusulkan perancangan Sistem Komunikasi Kabel Laut (SKKL) untuk akses data pulau Bawean. Trafik data dikirimkan melalui serat optik dari kota Surabaya menuju pulau Bawean yang berjarak 235 km. Dalam perancangan ini menggunakan tipe kabel singlemode G.655 dan 5 buah optikal amplifier jenis EDFA. Hasil perancangan menunjukan besarnya power link budget -9.525 dBm, SNR 25.35 dB, Q-factor 9.26, dan BER 1,009×10^-20.</p>
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6

Fiorini Granieri, Simone, Gerardo Maria Pagano, Marco Cecchetti, et al. "Turbostratic Carbon Nano Onion Electrode for High Power Density Vanadium Redox Flow Battery." ECS Meeting Abstracts MA2023-02, no. 59 (2023): 2874. http://dx.doi.org/10.1149/ma2023-02592874mtgabs.

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The redox flow battery (RFB) is one of the most promising technologies for stationary energy storage. It consists of a voltaic cell whose electrolytes are stored in tanks outside the system. Whilst the chemistries of the anodic and cathodic electrolytes define the energy density of a RFB system, its power density is determined primarily by its electrodes. These are typically porous carbon media on the surface of which the redox reactions occur. They are a critical component since they require a detailed engineering of electrocatalytically active surface area and mass transport. Still today, they remain the main cause of RFB low power density. In this work, we are showing a novel deposition method to improve the performance of commercially available carbon paper already used in RFB. The gain is thanks to the deposition of turbostratic carbon nano-onion (TCNO) nanoparticles on the carbon fibers of the paper. This process is performed with a proprietary technology called NanoJeD: a CVD in supersonic flow, which promises easy industrial scalability and a fine tunability of the nanoparticle properties. Moreover, with this system is possible to deposit over any substrate. NanoJeD consists in two chambers separated by a high aspect ratio slit. A precursor gas is injected through a porous plug from the top and a vacuum system is connected from the bottom. The slit allows the establishment of a high-pressure ratio between the two chambers and hence the formation of a supersonic jet. The precursor gas, a mixture of Argon (98.4%) and Acetylene (1.6%) flows between two electrodes where a radio frequency (RF) signal is fed (13.56 MHz). The RF ignites a non-thermal plasma in which the precursor molecules are ionized and dissociated into radicals, which polymerize forming hydrogenated carbon clusters and nanoparticles (NPs) of different sizes. Once formed, NPs are dragged through the slit by the gas stream and finally impact on the substrate. Therefore, it is possible to achieve a high throughput (500 mg h-1) and to deposit on a large area of 100 cm2 while precisely controlling the properties of the film. The resulting film has hundreds of squared meters per gram of surface area. For TCNO formation, the NP film is further annealed in vacuum at 1000°C for 2 hours. Using in situ transmission electron microscopy (TEM) and energy electron loss spectroscopy (EELS), we were able to visualize the progression of graphitization and changes in structural properties during annealing. The graphitization process starts in the outer layer and proceeds into the interior of the particle. The geometrical constrains of the NP (average diameter of 20nm) and shrinkage of the NP, allow the formation of curved, turbostratic, defective graphitic sheets. UV photoelectron spectroscopy (UPS) and Raman spectroscopy performed ex-situ allow the analysis of valence bands and structural defects. The high presence of defects and general disorder structure are accompanied with a remarkable increase in catalytic activity. Moreover, the annealing process leads to the sintering of the nanoparticles and the formation of an interface between the carbon fibre and the nanoparticles, as demonstrated by the increased thermal stability tested by. Both phenomena improve the adhesion between nanoparticles and with the surface, making the electrode suitable to be adopted in fluxed systems. The TCNO deposited on a carbon paper was tested as electrode in a Vanadium RFB. The kinetic activity and electrochemical properties were tested via in-situ Raman and in a three-electrode cell set-up. The results reveal an increased kinetic activity with respect to the untreated paper. Using in situ Raman we were able to show differences in redox mechanism between TCNO and bare carbon paper. A chronoamperometry test was used to obtain the transfer coefficient from a Tafel plot. These studies allow the correlation of the catalytic activity with the defectiveness of the TCNO nanoparticle. Vanadium RFB full cell measurements of the TCNO electrode show a drastic increase in performance, reaching an energy efficiency of 70.8% and 86.2% at current densities of 600 mA cm-2 and 200 mA cm-2, respectively. The electrolyte utilisation for these current densities is 59% for the former and 80% for the latter. To investigate the chemical and mechanical stability a stability test was performed. Results showed a low degradation rate of 0.004% EE per cycle. Moreover, TCNO can be used for other electrochemical applications only by adjusting the deposition and annealing parameters.
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7

Kumar, Ajay, Deepak Kedia, and Shelly Singla. "MZM–SOA based RoF system for 30-tuple millimeter-wave generation." Journal of Optical Communications, June 5, 2024. http://dx.doi.org/10.1515/joc-2024-0082.

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Abstract In this paper, we have reported radio over fiber system with 30-tuple millimeter-wave generation using dual parallel Mach–Zehnder modulator and semiconductor optical amplifier. The optimum choice of Mach–Zehnder modulator parameters has resulted into generation of signal lightwave and pump signal with frequency separation of 10f RF. Four wave mixing effect in semiconductor optical amplifier results into 30-tuple millimeter-wave signal. The proposed scheme is applicable to radio over fiber system with multiple base stations. The multiple number of frequencies such as 50 GHZ, 100 GHz, and 150 GHz have been generated using 5 GHz radio frequency only. NRZ data at 2.5 Gbps was modulated and successfully transmitted via optical fiber. The impact of injection current on the sideband ratio and BER is investigated. The proposed scheme confirms quality reception of demodulated signal at a transmission distance of 20 km.
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8

Ngo, Trang Thi Thu, Thu Anh Pham, Nhan Duc Nguyen, and Ngoc The Dang. "Hybrid OFDM RoF-Based WDM-PON/MMW Backhaul Architecture For Heterogeneous Wireless Networks." REV Journal on Electronics and Communications, March 6, 2018. http://dx.doi.org/10.21553/rev-jec.150.

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In this paper, a hybrid backhaul architecture, which is based on wavelength-division multiplexing passive optical networks (WDM-PON) and millimeter-wave (MMW) communications, is proposed to deliver orthogonal frequency-division multiplexing (OFDM) signals in heterogeneous wireless networks. MMW radio-over-fiber (RoF) technique, which combines the advantages of the both optical fiber and wireless communications, is used to simplify the base stations and provide flexibility long reach and high capacity connections. The feasibility of the proposed hybrid backhaul architecture is investigated via the bit-error rate (BER) performance of a downlink under the impacts of fiber nonlinear, wireless fading and noise components including clipping noise, amplifier noise and photodetector noise. The numerical results obtained from this study help to determine the optimum system parameters such as the optical launched power, modulation index, and amplifier gain so as to minimize the link’s BER.
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9

Chitnavis, Jai. "Silent burn: the hidden danger and effects of bright light from fibre-optic cables in arthroscopic knee surgery." Journal of Surgical Case Reports 2020, no. 4 (2020). http://dx.doi.org/10.1093/jscr/rjaa068.

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Abstract Following an uneventful arthroscopic menisectomy of the right knee, a white circular skin lesion, 1 cm in diameter, was noted on the anterior left thigh of a 23-year-old patient. The overlying paper surgical drape had not ignited nor produced smoke. Close inspection revealed a minute perforation in the drape with slight discolouration. No electro-cautery, radio-ablation or irritant skin preparation had been used during surgery. Tests failed to identify fault with the light source, fibre-optic cable or arthroscope. The lesion was diagnosed as a full-thickness thermal burn resulting from heat transmitted from a 300-W Xenon lamp via a detached fibre-optic cable. The effects of contact between an illuminated fibre-optic light cable and living human skin are described, with changes in appearances followed over 2 years. Patients may be burnt and permanently scarred without the knowledge of staff in operating theatres if detached light cables rest against surgical drapes.
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10

Jin, Wenhui, Ping Wang, Xiaopeng An, Congcong Zhu, Yongfei Li, and Yan Wang. "Anion Doping Synergistic Strategy Achieving Multi‐Interfaces and Modulated Dielectric Coupling for Efficient Electromagnetic Response." Small Methods, April 9, 2025. https://doi.org/10.1002/smtd.202500290.

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AbstractEfficient microwave absorbers are needed to address the electromagnetic pollution caused by the proliferation of new radio technologies and equipment. Excellent microwave absorption performance can be achieved by controlling the dielectric constant. Heteroatom‐doped bimetallic materials are promising electromagnetic wave absorption (EMA) materials due to their tunable structures and low cost. In particular, the presence of anionic sites significantly affects their dielectric constant and electrical conductivity. Herein, a 1D carbon nanofiber material is prepared by encapsulating FeCo nanoparticles in a fiber cavity by electrostatic spinning. Subsequently, tellurization, vulcanization, and selenization processes are carried out. FeTe2/ CoTe2@C exhibits stronger conductivity and dielectric loss due to the lower electronegativity of Te. The clever configuration of FeTe2, CoTe2, and C heterostructures obtained by Te doping generates multi‐heterogeneous interfaces that facilitate charge migration and enhance interfacial polarization, obtaining excellent EMA performance. FeTe2/CoTe2@C exhibits an optimum minimum reflection loss (RLmin) of −51.1 dB with a matching thickness of 2.0 mm, and the effective absorption bandwidth (EAB) reaches 4.2 GHz. Radar cross‐section (RCS) calculations show the great potential of FeTe2/CoTe2@C for practical military stealth technology. This study offers novel guidance for improving the EMA properties of transition metal matrix composites via anionic coordination modulation.
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11

Wayth, Randall, Marcin Sokolowski, Tom Booler, et al. "The Engineering Development Array: A Low Frequency Radio Telescope Utilising SKA Precursor Technology." Publications of the Astronomical Society of Australia 34 (2017). http://dx.doi.org/10.1017/pasa.2017.27.

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AbstractWe describe the design and performance of the Engineering Development Array, which is a low-frequency radio telescope comprising 256 dual-polarisation dipole antennas working as a phased array. The Engineering Development Array was conceived of, developed, and deployed in just 18 months via re-use of Square Kilometre Array precursor technology and expertise, specifically from the Murchison Widefield Array radio telescope. Using drift scans and a model for the sky brightness temperature at low frequencies, we have derived the Engineering Development Array’s receiver temperature as a function of frequency. The Engineering Development Array is shown to be sky-noise limited over most of the frequency range measured between 60 and 240 MHz. By using the Engineering Development Array in interferometric mode with the Murchison Widefield Array, we used calibrated visibilities to measure the absolute sensitivity of the array. The measured array sensitivity matches very well with a model based on the array layout and measured receiver temperature. The results demonstrate the practicality and feasibility of using Murchison Widefield Array-style precursor technology for Square Kilometre Array-scale stations. The modular architecture of the Engineering Development Array allows upgrades to the array to be rolled out in a staged approach. Future improvements to the Engineering Development Array include replacing the second stage beamformer with a fully digital system, and to transition to using RF-over-fibre for the signal output from first stage beamformers.
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12

Furniss, C., A. Carstens, and I. Cilliers. "Eustachian tube diverticulum chondroids and neck abscessation in a case of Streptococcus equi subsp. equi : clinical communication." Journal of the South African Veterinary Association 78, no. 3 (2007). http://dx.doi.org/10.4102/jsava.v78i3.311.

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A 12-year-old, grey, crossbred pony mare was presented with a swelling in the neck over the area of the 2nd cervical vertebra (C2), which was found to be painful on palpation. The neck was held stiffly. Radiography of the cervical region showed a focal area of increased radio-opacity over the dorsal, caudal and lateral aspect of the dorsal spinous process of C2. Ultrasound confirmed the presence of a hypoechoic area approximately 15 cm in diameter superimposed over the dorsal spinous process of C2. An aspirate was taken of the mass, which revealed purulent exudate confirming the diagnosis of an abscess. The abscess was lanced with a scalpel blade and samples of the purulent material revealed a pure culture of Streptococcus equi subsp. equi. The guttural pouches (Eustachian tube diverticulae (ETD)) were then evaluated endoscopically and multiple chondroids were seen filling most of the right ETD. Surgery was subsequently performed and 189 chondroids were removed via a right-sided hyovertebrotomy. The ETDs were flushed and penicillin installed into both ETDs on 3 different occasions via a catheter introduced using a fibre optic scope. This procedure was repeated until a negative culture status was achieved in order to eliminate the carrier status.
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13

Belkacem, Anes, and Ahmed Riad Borsali. "Simultaneous distribution of wired and two 2 × 2 MIMO wireless OFDM signals over an integrated RoF-PON system." Journal of Optical Communications, July 29, 2021. http://dx.doi.org/10.1515/joc-2021-0029.

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Abstract In this paper, the integration of the radio over fiber technology into a passive optical network (RoF-PON) is proposed to simultaneously distribute wired and two wireless standards each one transports 2 × 2 multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) signals. This simultaneous transmission is operated based on a single centralized optical wavelength and enabled by a polarization division multiplexing technique. The proposed RoF-PON system offers high spectral efficiency and is designed for unlicensed industrial, scientific, and medical bands at 2.4 and 5.8 GHz. The system performance is assessed by measuring the bit error rates (BERs) according to different access distances up to 30 km. After determining the optimum extinction ratio (ER) to modulate the baseband wired signal that allows jointly optical modulation of wireless signals using the same optical wavelength; all the 2 × 2 quadrature amplitude modulation (QAM) MIMO-OFDM wireless signals with a wired signal are successfully delivered without using forward error correction limit. Additionally, the system reliability has been confirmed by adopting other modulations schemes such as 8 and 16 phase-shift keying (PSK) that maintained good constellation diagrams performances. Whereas, the wired signal is analyzed according to its BER and quality Q-factor including high-quality eye diagram patterns. Also, the results revealed that the MIMO-OFDM signals mapped by 16 QAM scheme are given a better performance than PSK schemes when they are accompanied with high data rate baseband wired signal via a PON distance of 30 km.
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14

Ebrahim, Khalil Jasim, and Alauddin Al-Omary. "Effects of Sandstorms on Vehicular-to-Road Visible-Light Communication." Journal of Optical Communications, September 29, 2018. http://dx.doi.org/10.1515/joc-2018-0035.

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AbstractVisible light communication (VLC), popularly known as light fidelity (Li-Fi), is a promising alternative to overcome the limitations of radio-wave communication. VLC is a green technology which uses light-emitting diode (LED) illumination to transmit data without needing fibre cables. VLC is applicable for both indoor and outdoor communication. In this study, we investigate the effect of sandstorms on VLC via simulating a vehicular-to-road VLC (V2LC) outdoor application. Sandstorms are a weather phenomenon which frequently occurs in the Arab peninsula and other parts of the world; in this context, researchers have not thus far addressed the effect of sand particles, which absorb and scatter light, on VLC. Our simulation is conducted using MATLAB software (Natick, Massachusetts, U.S.A.), and the results show that the effect of sandstorms on VLC is similar to that of fog and rain as investigated by other researchers. However, sandstorms are also different in terms of the nature of sandstorm particles, with different sizes and refraction indices when compared with rain and fog particles. We also find that high-density-clay sandstorms, among other types of storms, most severely affect VLC communication and limit the transmission range. Other low- and medium-density storms less severely affect VLC while exhibiting a relatively larger communication range.
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Bessiere, P. S., C. Ramos Almeida, L. R. Holden, C. N. Tadhunter, and G. Canalizo. "QSOFEED : Relationship between star formation and active galactic nuclei feedback." Astronomy & Astrophysics, June 19, 2024. http://dx.doi.org/10.1051/0004-6361/202348795.

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Large-scale cosmological simulations suggest that feedback from active galactic nuclei black (AGN) plays a crucial role in galaxy evolution. black More specifically outflows are one of the mechanisms by which the accretion energy of the AGN is transferred to the interstellar medium (ISM), heating and driving out gas and impacting star formation (SF). The purpose of this study is to directly test this hypothesis utilising SDSS spectra of a well-defined sample of 48 low-redshift (z<0.14) type 2 quasars (QSO2s). By exploiting these data, we were able to characterise the kinematics of the warm ionised gas by performing a non-parametric analysis of the OIII 5007$ emission line. We also constrained the properties of the young stellar populations (YSP; Myr $) of their host galaxies via spectral synthesis modelling. These analyses revealed that 85<!PCT!> of the QSO2s display velocity dispersions in the warm ionised gas phase greater than that of the stellar component of their host galaxies, indicating the presence of AGN-driven outflows. We compared the gas kinematics with the intrinsic properties of the AGN and found that there is a positive correlation between gas velocity dispersion and 1.4 GHz radio luminosity -- but not with the AGN bolometric luminosity or Eddington ratio. This either suggests that the radio luminosity is the key factor driving outflows or that the outflows themselves are shocking the ISM and producing synchrotron emission. We found that 98<!PCT!> of the sample host YSPs to varying degrees, with star formation rates (SFRs) of $0 SFR averaged over 100 Myr. We compared the gas kinematics and outflow properties to the SFRs to establish possible correlations that could suggest that the presence of the outflowing gas could be impacting SF black but we found that no such correlation exists. This leads us to the conclusion that on the scales probed by the SDSS fibre (between 2 and 7 kpc diameters), AGN-driven outflows do not impact SF on the timescales probed in this study. However, we black find a positive correlation between the light-weighted stellar ages of the QSO2s and the black hole mass black which might indicate that successive AGN episodes lead to the suppression of SF over the course of galaxy evolution.
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16

Barker, Timothy Scott. "Information and Atmospheres: Exploring the Relationship between the Natural Environment and Information Aesthetics." M/C Journal 15, no. 3 (2012). http://dx.doi.org/10.5204/mcj.482.

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Our culture abhors the world.Yet Quicksand is swallowing the duellists; the river is threatening the fighter: earth, waters and climate, the mute world, the voiceless things once placed as a decor surrounding the usual spectacles, all those things that never interested anyone, from now on thrust themselves brutally and without warning into our schemes and manoeuvres (Michel Serres, The Natural Contract, p 3). When Michel Serres describes culture's abhorrence of the world in the opening pages of The Natural Contract he draws our attention to the sidelining of nature in histories and theories that have sought to describe Western culture. As Serres argues, cultural histories are quite often built on the debates and struggles of humanity, which are largely held apart from their natural surroundings, as if on a stage, "purified of things" (3). But, as he is at pains to point out, human activity and conflict always take place within a natural milieu, a space of quicksand, swelling rivers, shifting earth, and atmospheric turbulence. Recently, via the potential for vast environmental change, what was once thought of as a staid “nature” has reasserted itself within culture. In this paper I explore how Serres’s positioning of nature can be understood amid new communication systems, which, via the apparent dematerialization of messages, seems to have further removed culture from nature. From here, I focus on a set of artworks that work against this division, reformulating the connection between information, a topic usually considered in relation to media and anthropic communication (and something about which Serres too has a great deal to say), and nature, an entity commonly considered beyond human contrivance. In particular, I explore how information visualisation and sonification has been used to give a new sense of materiality to the atmosphere, repotentialising the air as a natural and informational entity. The Natural Contract argues for the legal legitimacy of nature, a natural contract similar in standing to Rousseau’s social contract. Serres’ss book explores the history and notion of a “legal person”, arguing for a linking of the scientific view of the world and the legal visions of social life, where inert objects and living beings are considered within the same legal framework. As such The Natural Contract does not deal with ecology per-se, but instead focuses on an argument for the inclusion of nature within law (Serres, “A Return” 131). In a drastic reconfiguring of the subject/object relationship, Serres explains how the space that once existed as a backdrop for human endeavour now seems to thrust itself directly into history. "They (natural events) burst in on our culture, which had never formed anything but a local, vague, and cosmetic idea of them: nature" (Serres, The Natural Contract 3). In this movement, nature does not simply take on the role of a new object to be included within a world still dominated by human subjects. Instead, human beings are understood as intertwined with a global system of turbulence that is both manipulated by them and manipulates them. Taking my lead from Serres’s book, in this paper I begin to explore the disconnections and reconnections that have been established between information and the natural environment. While I acknowledge that there is nothing natural about the term “nature” (Harman 251), I use the term to designate an environment constituted by the systematic processes of the collection of entities that are neither human beings nor human crafted artefacts. As the formation of cultural systems becomes demarcated from these natural objects, the scene is set for the development of culturally mediated concepts such as “nature” and “wilderness,” as entities untouched and unspoilt by cultural process (Morton). On one side of the divide the complex of communication systems is situated, on the other is situated “nature”. The restructuring of information flows due to developments in electronic communication has ostensibly removed messages from the medium of nature. Media is now considered within its own ecology (see Fuller; Strate) quite separate from nature, except when it is developed as media content (see Cubitt; Murray; Heumann). A separation between the structures of media ecologies and the structures of natural ecologies has emerged over the history of electronic communication. For instance, since the synoptic media theory of McLuhan it has been generally acknowledged that the shift from script to print, from stone to parchment, and from the printing press to more recent developments such as the radio, telephone, television, and Web2.0, have fundamentally altered the structure and effects of human relationships. However, these developments – “the extensions of man” (McLuhan)— also changed the relationship between society and nature. Changes in communications technology have allowed people to remain dispersed, as ideas, in the form of electric currents or pulses of light travel vast distances and in diverse directions, with communication no longer requiring human movement across geographic space. Technologies such as the telegraph and the radio, with their ability to seemingly dematerialize the media of messages, reformulated the concept of communication into a “quasi-physical connection” across the obstacles of time and space (Clarke, “Communication” 132). Prior to this, the natural world itself was the medium through which information was passed. Rather than messages transmitted via wires, communication was associated with the transport of messages through the world via human movement, with the materiality of the medium measured in the time it took to cover geographic space. The flow of messages followed trade flows (Briggs and Burke 20). Messages moved along trails, on rail, over bridges, down canals, and along shipping channels, arriving at their destination as information. More recently however, information, due to its instantaneous distribution and multiplication across space, seems to have no need for nature as a medium. Nature has become merely a topic for information, as media content, rather than as something that takes part within the information system itself. The above example illustrates a separation between information exchange and the natural environment brought about by a set of technological developments. As Serres points out, the word “media” is etymologically related to the word “milieu”. Hence, a theory of media should be always related to an understanding of the environment (Crocker). But humans no longer need to physically move through the natural world to communicate, ideas can move freely from region to region, from air-conditioned room to air-conditioned room, relatively unimpeded by natural forces or geographic distance. For a long time now, information exchange has not necessitated human movement through the natural environment and this has consequences for how the formation of culture and its location in (or dislocation from) the natural world is viewed. A number of artists have begun questioning the separation between media and nature, particularly concerning the materiality of air, and using information to provide new points of contact between media and the atmosphere (for a discussion of the history of ecoart see Wallen). In Eclipse (2009) (fig. 1) for instance, an internet based work undertaken by the collective EcoArtTech, environmental sensing technology and online media is used experimentally to visualize air pollution. EcoArtTech is made up of the artist duo Cary Peppermint and Leila Nadir and since 2005 they have been inquiring into the relationship between digital technology and the natural environment, particularly regarding concepts such as “wilderness”. In Eclipse, EcoArtTech garner photographs of American national parks from social media and photo sharing sites. Air quality data gathered from the nearest capital city is then inputted into an algorithm that visibly distorts the image based on the levels of particle pollution detected in the atmosphere. The photographs that circulate on photo sharing sites such as Flickr—photographs that are usually rather banal in their adherence to a history of wilderness photography—are augmented by the environmental pollution circulating in nearby capital cities. Figure 1: EcoArtTech, Eclipse (detail of screenshot), 2009 (Internet-based work available at:http://turbulence.org/Works/eclipse/) The digital is often associated with the clean transmission of information, as packets of data move from a server, over fibre optic cables, to be unpacked and re-presented on a computer's screen. Likewise, the photographs displayed in Eclipse are quite often of an unspoilt nature, containing no errors in their exposure or focus (most probably because these wilderness photographs were taken with digital cameras). As the photographs are overlaid with information garnered from air quality levels, the “unspoilt” photograph is directly related to pollution in the natural environment. In Eclipse the background noise of “wilderness,” the pollution in the air, is reframed as foreground. “We breathe background noise…Background noise is the ground of our perception, absolutely uninterrupted, it is our perennial sustenance, the element of the software of all our logic” (Serres, Genesis 7). Noise is activated in Eclipse in a similar way to Serres’s description, as an indication of the wider milieu in which communication takes place (Crocker). Noise links the photograph and its transmission not only to the medium of the internet and the glitches that arise as information is circulated, but also to the air in the originally photographed location. In addition to noise, there are parallels between the original photographs of nature gleaned from photo sharing sites and Serres’s concept of a history that somehow stands itself apart from the effects of ongoing environmental processes. By compartmentalising the natural and cultural worlds, both the historiography that Serres argues against and the wilderness photograph produces a concept of nature that is somehow outside, behind, or above human activities and the associated matter of noise. Eclipse, by altering photographs using real-time data, puts the still image into contact with the processes and informational outputs of nature. Air quality sensors detect pollution in the atmosphere and code these atmospheric processes into computer readable information. The photograph is no longer static but is now open to continual recreation and degeneration, dependent on the coded value of the atmosphere in a given location. A similar materiality is given to air in a public work undertaken by Preemptive Media, titled Areas Immediate Reading (AIR) (fig. 2). In this project, Preemptive Media, made up of Beatriz da Costa, Jamie Schulte and Brooke Singer, equip participants with instruments for measuring air quality as they walked around New York City. The devices monitor the carbon monoxide (CO), nitrogen oxides (NOx) or ground level ozone (O3) levels that are being breathed in by the carrier. As Michael Dieter has pointed out in his reading of the work, the application of sensing technology by Preemptive Media is in distinct contrast to the conventional application of air quality monitoring, which usually takes the form of extremely high resolution located devices spread over great distances. These larger air monitoring networks tend to present the value garnered from a large expanse of the atmosphere that covers individual cities or states. The AIR project, in contrast, by using small mobile sensors, attempts to put people in informational contact with the air that they are breathing in their local and immediate time and place, and allows them to monitor the small parcels of atmosphere that surround other users in other locations (Dieter). It thus presents many small and mobile spheres of atmosphere, inhabited by individuals as they move through the city. In AIR we see the experimental application of an already developed technology in order to put people on the street in contact with the atmospheres that they are moving through. It gives a new informational form to the “vast but invisible ocean of air that surrounds us and permeates us” (Ihde 3), which in this case is given voice by a technological apparatus that converts the air into information. The atmosphere as information becomes less of a vague background and more of a measurable entity that ingresses into the lives and movements of human users. The air is conditioned by information; the turbulent and noisy atmosphere has been converted via technology into readable information (Connor 186-88). Figure 2: Preemptive Media, Areas Immediate Reading (AIR) (close up of device), 2011 Throughout his career Serres has developed a philosophy of information and communication that may help us to reframe the relationship between the natural and cultural worlds (see Brown). Conventionally, the natural world is understood as made up of energy and matter, with exchanges of energy and the flows of biomass through food webs binding ecosystems together (DeLanda 120-1). However, the tendencies and structures of natural systems, like cultural systems, are also dependent on the communication of information. It is here that Serres provides us with a way to view natural and cultural systems as connected by a flow of energy and information. He points out that in the wake of Claude Shannon’s famous Mathematical Theory of Communication it has been possible to consider the relationship between information and thermodynamics, at least in Shannon’s explanation of noise as entropy (Serres, Hermes74). For Serres, an ecosystem can be conceptualised as an informational and energetic system: “it receives, stores, exchanges, and gives off both energy and information in all forms, from the light of the sun to the flow of matter which passes through it (food, oxygen, heat, signals)” (Serres, Hermes 74). Just as we are related to the natural world based on flows of energy— as sunlight is converted into energy by plants, which we in turn convert into food— we are also bound together by flows of information. The task is to find new ways to sense this information, to actualise the information, and imagine nature as more than a welter of data and the air as more than background. If we think of information in broad ranging terms as “coded values of the output of a process” (Losee 254), then we see that information and the environment—as a setting that is produced by continual and energetic processes—are in constant contact. After all, humans sense information from the environment all the time; we constantly decode the coded values of environmental processes transmitted via the atmosphere. I smell a flower, I hear bird songs, and I see the red glow of a sunset. The process of the singing bird is coded as vibrations of air particles that knock against my ear drum. The flower is coded as molecules in the atmosphere enter my nose and bind to cilia. The red glow is coded as wavelengths from the sun are dispersed in the Earth’s atmosphere and arrive at my eye. Information, of course, does not actually exist as information until some observing system constructs it (Clarke, “Information” 157-159). This observing system as we see the sunset, hear the birds, or smell the flower involves the atmosphere as a medium, along with our sense organs and cognitive and non-cognitive processes. The molecules in the atmosphere exist independently of our sense of them, but they do not actualise as information until they are operationalised by the observational system. Prior to this, information can be thought of as noise circulating within the atmosphere. Heinz Von Foester, one of the key figures of cybernetics, states “The environment contains no information. The environment is as it is” (Von Foester in Clarke, “Information” 157). Information, in this model, actualises only when something in the world causes a change to the observational system, as a difference that makes a difference (Bateson 448-466). Air expelled from a bird’s lungs and out its beak causes air molecules to vibrate, introducing difference into the atmosphere, which is then picked up by my ear and registered as sound, informing me that a bird is nearby. One bird song is picked up as information amid the swirling noise of nature and a difference in the air makes a difference to the observational system. It may be useful to think of the purpose of information as to control action and that this is necessary “whenever the people concerned, controllers as well as controlled, belong to an organised social group whose collective purpose is to survive and prosper” (Scarrott 262). Information in this sense operates the organisation of groups. Using this definition rooted in cybernetics, we see that information allows groups, which are dependent on certain control structures based on the sending and receiving of messages through media, to thrive and defines the boundaries of these groups. We see this in a flock of birds, for instance, which forms based on the information that one bird garners from the movements of the other birds in proximity. Extrapolating from this, if we are to live included in an ecological system capable of survival, the transmission of information is vital. But the form of the information is also important. To communicate, for example, one entity first needs to recognise that the other is speaking and differentiate this information from the noise in the air. Following Clarke and Von Foester, an observing system needs to be operational. An art project that gives aesthetic form to environmental processes in this vein—and one that is particularly concerned with the co-agentive relation between humans and nature—is Reiko Goto and Tim Collin’s Plein Air (2010) (fig. 3), an element in their ongoing Eden 3 project. In this work a technological apparatus is wired to a tree. This apparatus, which references the box easels most famously used by the Impressionists to paint ‘en plein air’, uses sensing technology to detect the tree’s responses to the varying CO2 levels in the atmosphere. An algorithm then translates this into real time piano compositions. The tree’s biological processes are coded into the voice of a piano and sensed by listeners as aesthetic information. What is at stake in this work is a new understanding of atmospheres as a site for the exchange of information, and an attempt to resituate the interdependence of human and non-human entities within an experimental aesthetic system. As we breathe out carbon dioxide—both through our physiological process of breathing and our cultural processes of polluting—trees breath it in. By translating these biological processes into a musical form, Collins and Gotto’s work signals a movement from a process of atmospheric exchange to a digital process of sensing and coding, the output of which is then transmitted through the atmosphere as sound. It must be mentioned that within this movement from atmospheric gas to atmospheric music we are not listening to the tree alone. We are listening to a much more complex polyphony involving the components of the digital sensing technology, the tree, the gases in the atmosphere, and the biological (breathing) and cultural processes (cars, factories and coal fired power stations) that produce these gases. Figure 3: Reiko Goto and Tim Collins, Plein Air, 2010 As both Don Ihde and Steven Connor have pointed out, the air that we breathe is not neutral. It is, on the contrary, given its significance in technology, sound, and voice. Taking this further, we might understand sensing technology as conditioning the air with information. This type of air conditioning—as information alters the condition of air—occurs as technology picks up, detects, and makes sensible phenomena in the atmosphere. While communication media such as the telegraph and other electronic information distribution systems may have distanced information from nature, the sensing technology experimentally applied by EcoArtTech, Preeemptive Media, and Goto and Collins, may remind us of the materiality of air. These technologies allow us to connect to the atmosphere; they reformulate it, converting it to information, giving new form to the coded processes in nature.AcknowledgmentAll images reproduced with the kind permission of the artists. References Bateson, Gregory. Steps to an Ecology of Mind. Chicago: University of Chicago Press, 1972. Briggs, Asa, and Peter Burke. A Social History of the Media: From Gutenberg to the Internet. Maden: Polity Press, 2009. Brown, Steve. “Michel Serres: Science, Translation and the Logic of the Parasite.” Theory, Culture and Society 19.1 (2002): 1-27. Clarke, Bruce. “Communication.” Critical Terms for Media Studies. Eds. Mark B. N. Hansen and W. J. T. Mitchell. Chicago: University of Chicago Press, 2010. 131-45 -----. “Information.” Critical Terms for Media Studies. Eds. Mark B. N. Hansen and W. J. T. Mitchell. Chicago: University of Chicago Press, 2010. 157-71 Crocker, Stephen. “Noise and Exceptions: Pure Mediality in Serres and Agamben.” CTheory: 1000 Days of Theory. (2007). 7 June 2012 ‹http://www.ctheory.net/articles.aspx?id=574› Connor, Stephen. The Matter of Air: Science and the Art of the Etheral. London: Reaktion, 2010. Cubitt, Sean. EcoMedia. Amsterdam and New York: Rodopi, 2005 Deiter, Michael. “Processes, Issues, AIR: Toward Reticular Politics.” Australian Humanities Review 46 (2009). 9 June 2012 ‹http://www.australianhumanitiesreview.org/archive/Issue-May-2009/dieter.htm› DeLanda, Manuel. 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Albany: State University of New York, 2009 Scarrott, G.C. “The Nature of Information.” The Computer Journal 32.3 (1989): 261-66 Serres, Michel. Hermes: Literature, Science Philosophy. Baltimore: The John Hopkins Press, 1982. -----. The Natural Contract. Trans. Elizabeth MacArthur and William Paulson. Ann Arbor: The University of Michigan Press, 1992/1995. -----. Genesis. Trans. Genevieve James and James Nielson. Ann Arbor: The University of Michigan Press, 1982/1995. -----. “A Return to the Natural Contract.” Making Peace with the Earth. Ed. Jerome Binde. Oxford: UNESCO and Berghahn Books, 2007. Strate, Lance. Echoes and Reflections: On Media Ecology as a Field of Study. New York: Hampton Press, 2006 Wallen, Ruth. “Ecological Art: A Call for Intervention in a Time of Crisis.” Leonardo 45.3 (2012): 234-42.
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