Light Tower Research Articles

Research on the annual average thermal power of heliostat field in tower solar energy

The concentrating mirror field is a concentrating and heat collecting subsystem in the tower solar thermal power station, and its optical performance directly affects the solar energy utilization efficiency of the power station. In this paper, the coordinate system of heliostat field and single heliostat is established, and the grid division technology is introduced to describe its reflection effect on sunlight and its occlusion. In this paper, the shadow occlusion loss that affects the optical efficiency is divided into three parts, including incident light occlusion loss, reflected light occlusion loss and absorption tower shadow occlusion loss. For any time, the output power of the heliostat near the solar direction is small, while the output power of the heliostat far away from the solar direction is large. Compared with other influencing factors, the cosine loss has the greatest influence on the heliostat field, and the center of the absorption tower installed in the circular heliostat field is obtained. The size of the heliostat is a square with a side length of 6m, the installation height is 4m, and the annual average optical efficiency is 0.6216 when the position of the heliostat is determined. The annual average output thermal power is 36.3958 MW, and the annual average output thermal power per unit mirror area is 0.5794 .

Increased tower eigenfrequencies on floating foundations and their implications for large two- and three-bladed turbines

If the tower of a bottom-fixed turbine is put on a floating foundation, such as a spar, semi-submersible, or barge, its eigenfrequency increases. In the investigated case, the tower eigenfrequency rose to about twice its previous value. For bottom-fixed applications, the comparatively high blade-passing frequency of a three-blade turbine (3P) leaves a great bandwidth to design a light and soft tower with a low-enough eigenfrequency. On one of those floaters, however, the eigenfrequency of the same tower might neither be high nor low enough to avoid eigenfrequency excitation by 3P around rated speed. Due to the lower blade passing frequency of a two-bladed wind turbine (2P), the same tower eigenfrequency is high enough by default, enabling considerable material savings or at least eliminating the severe eigenfrequency excitation issue of its bottom-fixed version. Additionally, cost benefits in the whole life-cycle of two-bladed turbines remain. 20MW two- and three-bladed turbines were analyzed numerically on an upscaled version of the UMaine VolturnUS-S semi-submersible, confirming the reasoning.

The Scale of Supersymmetry Breaking and the Dark Dimension

We argue for a relation between the supersymmetry breaking scale and the measured value of the dark energy density Λ. We derive it by combining two quantum gravity consistency swampland constraints, which tie the dark energy density Λ and the gravitino mass M3/2, respectively, to the mass scale of a light Kaluza-Klein tower and, therefore, to the UV cut-off of the effective theory. Whereas the constraint on Λ has recently led to the Dark Dimension scenario, with a prediction of a single mesoscopic extra dimension of the micron size, we use the constraint on M3/2 to infer the implications of such a scenario for the scale of supersymmetry breaking. We find that a natural scale for supersymmetry signatures isM=OΛ18=OTeV.\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ M=\\mathcal{O}\\left({\\Lambda}^{\\frac{1}{8}}\\right)=\\mathcal{O}\\left(\ extrm{TeV}\\right). $$\\end{document}This mass scale is within reach of LHC and of the next generation of hadron colliders. Finally, we discuss possible string theory and effective supergravity realizations of the Dark Dimension scenario with broken supersymmetry.

The dark dimension and the Swampland

Motivated by principles from the Swampland program, which characterize requirements for a consistent UV completion of quantum gravity, combined with observational data, we are led to a unique corner of the quantum gravity landscape. In particular, using the Distance/Duality conjecture and the smallness of dark energy, we predict the existence of a light tower of states and a unique extra mesoscopic dimension of length lsim {Lambda}^{-frac{1}{4}}sim {10}^{-6}m , with extra massless fermions propagating on it. This automatically leads to a candidate for a tower of sterile neutrinos, and an associated active neutrino mass scale {m}_{nu}sim {leftlangle Hrightrangle}^2{Lambda}^{-frac{1}{12}}{M}_{textrm{pl}}^{-frac{2}{3}} . Moreover, assuming the mechanism for stabilization of this dark dimension leads to similar masses for active and sterile neutrinos we are led to the prediction of a Higgs vev leftlangle Hrightrangle sim {Lambda}^{frac{1}{6}}{M}_{textrm{pl}}^{frac{1}{3}} . Another prediction of the scenario is a species scale hat{M}sim {Lambda}^{frac{1}{12}}{M}_{textrm{pl}}^{frac{2}{3}}sim {10}^9hbox{--} {10}^{10} GeV, corresponding to the higher-dimensional Planck scale. This energy scale may be related to the resolution of the instability of the Higgs effective potential present at a scale of ~1011 GeV. We also speculate about the interplay between this energy scale and the GZK limit on ultra-high energy cosmic rays.

Closing the Open System

This essay looks at the algorithm written by Franco-Hungarian spatial artist Nicolas Schöffer for the Tour Lumière Cybernétique, a cybernetic light tower created for Paris’s La Défense district in the 1960s and ’70s. By revisiting the tower’s computer programme, this essay aims to understand how it was thought to operate as an open system by receiving data from its surrounding environment. The review of the programme questions how the probability distributions Schöffer included in the algorithm to ensure a random treatment of predictable city data was imagined to avoid stagnation, repetition and programmatic saturation, all elements essential to maintaining the tower’s open framework. The goal of the essay is to provide a coherent interpretation of the computer programme as well as a comprehensive description of its mathematical elements, so that future readers of La Tour Lumière Cybernétique can gain an insight into the behaviour of the tower.

Optimization Design of Feed Tower for High-frequency Band Multi-beam Antenna on Satellite

Aiming at the layout of a certain feed array for multi-beam antenna on satellite, a feed tower design method based on 3D printing technology is proposed. This design method uses aluminum alloy 3D printing to form the main support structure under the premise of avoiding the installation holes and layout positions, and adopts the combination of the main structure of the honeycomb lattice and the local solid structure to reduce the structural quality. The mechanical analysis and optimization of the design model are carried out by combining the actual test data of the mechanical test plate and ANSYS, in which the actual product is tested and verified. The light feed tower can fully meet the requirements of high-frequency multi-beam antenna feed array for high precision and lightweight, which has a certain reference value for the miniaturized design of the antenna.

Large and small non-extremal black holes, thermodynamic dualities, and the Swampland

In this paper we discuss black hole solutions parametrized by their entropy mathcal{S} and temperature mathcal{T} in gravitational effective theories. We are especially interested in the analysis of the boundary regions in the mathcal{T} − mathcal{S} diagram, i.e. large/small values of entropy and temperature, and their relation to Swampland constraints. To explore this correlation, we couple the gravitational theories to scalar fields and connect limits of thermodynamic quantities of black holes to scalar field excursions in the corresponding solutions. Whenever the scalar fields traverse an infinite field distance, the Swampland Distance Conjecture allows for a reformulation in terms of entropy- or temperature-distance. The effective theories with scalars we investigate are Einstein-Maxwell-dilaton theory as well as mathcal{N} = 2 supergravity in four dimensions. The relation of the latter to type II string theory compactified on Calabi-Yau 3-folds often allows for a direct identification of the corresponding light tower of states. These setups also point towards various dualities between asymptotic regions of the black hole solution. In the context of mathcal{N} = 2 supergravity black holes, these thermodynamic dualities have an interpretation in terms of T- and S-dualities along the internal directions and their natural action on Kaluza-Klein and winding states.

Design and Implementation of a Reliable and Secure Controller for Smart Home Applications Based on PLC

Programmable logic controllers (PLCs) are increasingly being used to realize modern safety-critical instrumentation and control (IC) applications. Examples of these applications are industrial automation and control systems, plant process safety protection systems, smart home systems and digital IC systems embedded in nuclear power plants (NPPs) that require high levels of performance, reliability, and flexibility. The PLC is a flexible, programmable, and robust digital device that can execute all logical and mathematical runtime functions of the IC application and operate in harsh-critical environments. This paper proposes a PLC-based home security controller based on the ladder logic programming model. The design, analysis, and hardware implementation of this controller are presented in this paper. The designed system consists of three basic modules which are a sensing module used for reading the data of the input field devices for the smart home application, a computation-based decisional module used for executing the programming model, and an actuating module used for sending the control commands to the output field devices. The proposed home security system utilized different types of sensors such as a laser photoelectric sensor, a motion or proximity sensor, and a limit switch. In addition, a siren speaker, a light tower including three lights red, yellow, and green, two push-pull switches and emergency push-pull buttons were used as control inputs and output indicators in the implementation of this work This designed system is implemented on the Allen-Bradley CompactLogix PLC controller and Human Machine Interface (HMI) panel programmed as the graphical user interface. The experimental simulation results of the real hardware connection demonstrate that the proposed system is reliable, safe, and feasible for smart home security applications.

Wind Load Analysis on Different Configuration on Stadium Light Pole

Abstract: In this work, a comprehensive study is made in a dynamic manner to understand the effect of this corrosive induced structural failure of a monopile flood light tower. Various climatic conditions subjected to rural and urban environments are considered to understand the source of failure and these results are effectively utilized to optimize the design of these structures to increase their fatigue life in turn reduces the possibility of catastrophic failures. Computational fluid dynamics (CFD) and Finite element analysis (FEA) play a vital role in conceptual design and design for development in industries and research where pure mathematical and experimental approaches are next to impossible. Thanks to these technologies many insights are revealed during the design evolution of a product that helps in optimum design of a product. This work utilizes the surface chemical reaction capability that is available in Ansys Fluent to conduct a detailed aerodynamic study for various wind conditions and to locate the place of maximum corrosion and these inferences are in turn will be utilized in further FEA analysis to predict the structural failures.Finally these interpretations are applied in reaching an optimum monopile structure with design retro-fittings and design alterations that enhance the applicability of these structures. Keywords: Monopile light tower, CFD ( Computational Fluid Dynamics), FEA (Finite Element Analysis), fatigue life

Monitoring and Modeling Tree Bat (Genera: Lasiurus, Lasionycteris) Occurrence Using Acoustics on Structures off the Mid-Atlantic Coast-Implications for Offshore Wind Development.

Simple Summary“Tree bats” are North American bats that day-roost in trees year-round and undertake seasonal migration in lieu of hibernation. These bats have been shown to be highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. Therefore, as offshore wind energy expands off the eastern U.S. coast, there is some concern about potential impacts. We monitored bats in coastal Virginia, USA, using acoustic monitors—devices that collect the unique echolocation call signatures of bat species. We found that nightly tree bat visitation offshore or on barrier islands was associated with wind speed, temperature, visibility, and seasonality. Using statistical modeling, we developed a predictive tool to assess occurrence probabilities at varying levels of wind speed, temperature, and seasonality. Probability of occurrence and therefore assumed risk to collision is highest on high temperature and visibility nights, low wind speed nights, and during the spring and fall seasons. We suggest a similar modeling regime could be used to predict the occurrence of bats at offshore wind sites to inform potential mitigation efforts.In eastern North America, “tree bats” (Genera: Lasiurus and Lasionycteris) are highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. This raises concern about ongoing expansion of offshore wind-energy development off the Atlantic Coast. Season, atmospheric conditions, and site-level characteristics such as local habitat (e.g., forest coverage) have been shown to influence wind turbine collision rates by bats onshore, and therefore may be related to risk offshore. Therefore, to assess the factors affecting coastal presence of bats, we continuously gathered tree bat occurrence data using stationary acoustic recorders on five structures (four lighthouses on barrier islands and one light tower offshore) off the coast of Virginia, USA, across all seasons, 2012–2019. We used generalized additive models to describe tree bat occurrence on a nightly basis. We found that sites either indicated maternity or migratory seasonal occurrence patterns associated with local roosting resources, i.e., presence of trees. Across all sites, nightly occurrence was negatively related to wind speed and positively related to temperature and visibility. Using predictive performance metrics, we concluded that our model was highly predictive for the Virginia coast. Our findings were consistent with other studies—tree bat occurrence probability and presumed mortality risk to offshore wind-energy collisions is highest on low wind speed nights, high temperature and visibility nights, and during spring and fall. The high predictive model performance we observed provides a basis for which managers, using a similar monitoring and modeling regime, could develop an effective curtailment-based mitigation strategy.

FINITE ELEMENT MODELING OF CFRP COMPOSITE POLE STRUCTURES

— In recent years, FRP composites, which are made of reinforcing fibers and a thermosetting resin, have been widely used as advanced construction materials. The tapered FRP poles are currently considered attractive in the application of the light poles and electrical transmission tower element. A finite element (FE) program was used to perform a nonlinear numerical analysis to model the static flexural behavior of CFRP poles. A parametric study was carried out to study the effect of replacing glass fiber (GFRP) by carbon fiber (CFRP) on the FRP pole behaviors. The ultimate capacity, top deflection and stiffness increase are presented. The study demonstrates that replacing carbon fiber by glass fiber of the FRP poles a good improvement achieved. The total load capacity of the FRP poles and the stiffness increased with increasing the percentage of carbon fiber.

H0 tension, swampland conjectures, and the epoch of fading dark matter

Motivated by the swampland dS conjecture, we consider a rolling scalar field as the source of dark energy. Furthermore, the swampland distance conjecture suggests that the rolling field will lead at late times to an exponentially light tower of states. Identifying this tower as residing in the dark sector suggests a natural coupling of the scalar field to the dark matter, leading to a continually reducing dark matter mass as the scalar field rolls in the recent cosmological epoch. The exponent in the distance conjecture, $\tilde{c}$, is expected to be an $\mathcal{O}(1)$ number. Interestingly, when we include the local measurement of $H_0$, our model prefers a non-zero value of the coupling $\tilde{c}$ with a significance of $2.8\sigma$ and a best-fit at $\tilde{c} \sim 0.3$. Modifying the recent evolution of the universe in this way improves the fit to data at the $2\sigma$ level compared to $\Lambda$CDM. This string-inspired model automatically reduces cosmological tensions in the $H_0$ measurement as well as $\sigma_8$.

The Black Hole Entropy Distance Conjecture and Black Hole Evaporation

AbstractWe extend the recently proposed Black Hole Entropy Distance Conjecture to the case of charged black holes in de Sitter space. By systematically studying distances in the space of black hole geometries with multiple horizons, we find that the distance is generically related to the logarithm of the entropy. From the infinite distance conjecture this predicts the appearance of a massless tower of modes in the limit of infinite entropy. Further, we study the evaporation of these black holes and relate it to the geometric distance. We find that the corresponding distance to the final stage of evaporation is finite. We conclude that evaporation does not lead to the appearance of a light tower of black hole microstates.

Response Analysis of A Heat-absorbing Tower under Near-field Earthquake

In order to better study the impact of near-field vibration pulse effects on high-rise structures, a random point source method and an equivalent velocity pulse superposition method were used to generate 26 multi-environmental near-field vibration samples with pulse effects for 7-degree fortification. Through the finite element modeling and analysis, the vibration type of the light and heat tower structure is obtained, and the seismic response of the heat absorption tower is analyzed by the generated random ground motion, and the mean value and variance of the structure dynamic amplification factor, base shear force and displacement angle are obtained. Coefficient of variation. The results show that the random seismic response of the structure shows an obvious discrete type, the dispersion of the acceleration amplification factor increases with the height of the tower, the displacement response increases with the height of the tower, and the steel structure on the top of the tower has a significant whiplash effect.

Infinite black hole entropies at infinite distances and tower of states

The aim of this paper is to elucidate a close connection between the black hole area law and the infinite distance conjecture in the context of the swampland. We consider families of black hole geometries, parametrized by their event horizon areas or by the values of their entropies, and show that the infinite entropy limit is always at infinite distance in the space of black hole geometries. It then follows from the infinite distance conjecture that there must be a tower of states in the infinite entropy limit, and that ignoring these towers on the horizon of the black hole would invalidate the effective theory when the entropy becomes large. We call this the black hole entropy distance conjecture. We then study two candidates for the tower of states. The first are the Kaluza-Klein modes of the internal geometry of extremal N=2 black holes in string theory, whose masses on the horizon are fixed by the N=2 attractor formalism, and given in terms of the black hole charges similarly to the entropy. However, we observe that it is possible to decouple their masses from the entropy, so that they cannot generically play the role of the tower. We thus consider a second kind of states: inspired by N-portrait quantum models of non-extremal black holes, we argue that the Goldstone-like modes that interpolate among the black hole microstates behave like the expected light tower of states.

AdS and the Swampland

We study aspects of anti-de Sitter space in the context of the Swampland. In particular, we conjecture that the near-flat limit of pure AdS belongs to the Swampland, as it is necessarily accompanied by an infinite tower of light states. The mass of the tower is power-law in the cosmological constant, with a power of 12 for the supersymmetric case. We discuss relations between this behaviour and other Swampland conjectures such as the censorship of an unbounded number of massless fields, and the refined de Sitter conjecture. Moreover, we propose that changes to the AdS radius have an interpretation in terms of a generalised distance conjecture which associates a distance to variations of all fields. In this framework, we argue that the distance to the Λ→0 limit of AdS is infinite, leading to the light tower of states. We also discuss implications of the conjecture for de Sitter space.

Effects of Mounting Height, Offset Distance, and Number of Light Towers on Drivers’ Visual Performance and Discomfort Glare in Work Zones

Portable light towers are a significant source of glare to motorists entering a work zone. Although existing research has evaluated the effect of light tower orientation on visibility and glare, the effects of factors like mounting height, offset distance from the roadway, and number of light towers in the work zone, on visual performance and discomfort glare is not known. Understanding these relationships can help in developing illuminating guidelines for work zones that can reduce glare for drivers. The goal of this paper is to understand the effect of mounting height, offset distance to the roadway, and number of light towers in the work zone on drivers’ visual performance and discomfort glare. Participants drove through a realistic work zone and evaluated portable light towers in varying mounting heights, offset distances, and number of light towers in the work zone. Results showed that the mounting height and offset distances play a critical role in affecting the driver’s visual performance and discomfort glare rating. Portable light towers, irrespective of wattage and lumen output, at lower than a mounting height of 20 ft and closer to the roadway result in decreasing driver visual performance and increasing their discomfort glare. Portable light towers should be mounted at a height of at least 20 ft and balloon light towers with higher wattage (4,000 W and greater) and lumen output (400,000 lumens and greater) should be located at an offset distance of at least 10 ft from the roadway.

Del purismo al espacio puro de Le Corbusier a través del color

This article studies the influence of cubism and purism on Le Corbusier’s architectural work, not only in the 1920s, but throughout his career. He applied the colour theories that were being used in these movements to architecture, initially in order to deform space, by means of the ideas of colour held by artists such as Leger. He was finally able to achieve space through colour, without the need to define space through materialisation in order to delimit it, as was typically the case. This new idea of space brought about a change in the traditional concept of space, which we call pure space, as a clear reference to purism, an expression used by Rainer Maria Rilke in the Duino Elegies , published in 1922, when Le Corbusier was involved in purism. This concept will be studied through the east light tower of the chapel of Notre Dame du Haut, Ronchamp , partially painted in vermilion, and in its west-facing twin, painted in white. Keywords: Notre Dame du Haut Ronchamp , purism, light tower.

UTILIZATION OF UNMANNED AIRCRAFT SYSTEMS FOR DEPARTMENT OF TRANSPORTATION OPERATIONS

The Federal Aviation Administration (FAA) has not yet standardized usage regulations for unmanned aircraft systems (UASs) and those regulations are still evolving. Consequently, this lack of standardization creates tedious obstacles for UAS users. The goal of this research was to provide a justified recommendation to the Department of Transportation regarding the benefits of UAS implementation into routine operations, as well as advice on specific UAS equipment that benefits KDOT. This paper includes a literature review that lists commercial companies currently using UASs after gaining a Certificate of Authorization exemption and describes research of using UASs for the purposes of assisting or replacing tasks at a state’s DOT. Potential applications and concerns regarding UAS usage are also included in the literature review. An online survey was created and sent to all USDOT offices with questions pertaining to demographics, current operations, and if that DOT office is currently using the new technology, or is only considering it. An economic analysis was completed using data from several departments. Out of the nine areas considered for implementing UAS, seven could realize benefits in safety, efficiency, and a possible cost savings. The recommended UAS applications are in bridge inspection, radio tower inspection, surveying, road mapping, high-mast light tower inspection, stockpile measurement, and aerial photography.

Effect of Work Zone Lighting on Drivers’ Visual Performance and Perceptions of Glare

Nighttime crashes at work zones are major concerns for construction workers and motorists. Although in a majority of the U.S. states, department of transportation specifications for work zone lighting mention that contractors should reduce glare for workers and drivers, only two states advocate detailed specifications like light positions, orientation, and light levels. Although some studies have examined the impact of glare from work zone lights on workers and others have calculated veiling luminance levels for drivers in the work zone, the effect of work zone lighting on drivers’ visual performance and glare perception has never been studied in a realistic setting. The goal of this study was to understand the impact of commercially available portable light towers (metal halide, LED, and balloon) and their orientation on drivers’ visual performance and their perceptions of glare. Participants drove through a realistic work zone simulated on the Virginia Smart Road. Visual performance was assessed by a detection task and perception of visibility and glare were assessed by questionnaires. Results indicated that the type of light tower and its orientation affect visual performance and perceptions of visibility and glare. Light towers aimed toward the driver resulted in lowering drivers’ visual performance, both objectively and subjectively. When the light towers were aimed away from or perpendicular to the driver, the visual performance was higher and the differences in visual performance between the types of light towers were minimal. These findings indicate that these orientations should be preferred for work zone light towers.