Modern cosmologies from empty Kaluza-Klein solutions in 5D

We show that the empty five-dimensional solutions of Davidson-Sonnenschtein-Vozmediano, {\em Phys. Rev.} {\bf D32} (1985)1330, in the "old" Kaluza-Klein gravity, under appropriate interpretation can generate an ample variety of cosmological models in 4D, which include the higher-dimensional modifications to general relativity predicted by "modern" versions of noncompactified 5D gravity as, e.g., induced-matter and braneworld theories. This is the first time that these solutions are investigated in a systematic way as embeddings for cosmological models in 4D. They provide a different formulation, which is complementary to the approaches used in current versions of 5D relativity.Comment: Accepted for publication in JHE

Cost Analysis and Water Conservation Potential of Irrigation Technologies in the Texas Panhandle Water Planning Area

Six irrigation systems are analyzed considering cost and potential water savings. The investment cost of furrow and drip is $115,800 and$260,120, respectively. The cost of quarter mile pivot ranges from $59,000 to$64,000. Per ac-in variable pumping cost ranges $9.96 to$14.86 assuming natural gas price $7.00 per MCF.Irrigation Technology, Ground Water Planning, Texas Panhandle, Water Conservation, Ogallala, Agribusiness, Environmental Economics and Policy, Farm Management, Production Economics, Resource /Energy Economics and Policy,

Development of an Oxy-Fuel Combustion System in a Compression-Ignition Engine for Ultra-Low Emissions Powerplants Using CFD and Evolutionary Algorithms

[EN] This study uses an optimization approach for developing a combustion system in a compression-ignition engine that is able to operate under oxy-fuel conditions, and produces mainly CO2 and H2O as exhaust gases. This is achieved because the combustion concept uses pure oxygen as an oxidizer, instead of air, avoiding the presence of nitrogen. The O-2 for the combustion system can be obtained by using a mixed ionic-electronic conducting membrane (MIEC), which separates the oxygen from the air onboard. The optimization method employed maximizes the energy conversion of the system, reducing pollutant emissions (CxHy, particulate matter, and carbon monoxides) to levels near zero. The methodology follows a novel approach that couples computational fluid dynamics (CFD) and particle swarm optimization (PSO) algorithms to optimize the complete combustion system in terms of engine performance and pollutant generation. The study involves the evaluation of several inputs that govern the combustion system design in order to fulfill the thermo-mechanical constraints. The parameters analyzed are the piston bowl geometry, fuel injector characteristics, air motion, and engine settings variables. Results evince the relevance of the optimization procedure, achieving very low levels of gaseous pollutants (CxHy and CO) in the optimum configuration. The emissions of CO were reduced by more than 10% while maintaining the maximum in-cylinder pressure within the limit imposed for the engine. However, indicated efficiency levels are compromised if they are compared with an equivalent condition operating under conventional diesel combustion.This research work has been supported by Grant PDC2021-120821-I00 funded by MCIN/AEI/10.13039/501100011033 and by EuropeanUnion NextGenerationEU/PRTR. This research was partially supported by Agencia Valenciana de la Innovacio (AVI) through the project "Demostrador de un motor de oxicombustion con captura de CO2" (INNVA1/2021/38).Serrano, J.; Bracho Leon, G.; Gómez-Soriano, J.; Spohr-Fernandes, C. (2022). Development of an Oxy-Fuel Combustion System in a Compression-Ignition Engine for Ultra-Low Emissions Powerplants Using CFD and Evolutionary Algorithms. Applied Sciences. 12(14):1-27. https://doi.org/10.3390/app12147104127121

Photosynthesis, yield and raw material quality of sugarcane injured by multiple pests

Understanding sugarcane (Saccharum spp.) response to multiple pest injury, sugarcane borer (Diatraea saccharalis) and spittlebug (Mahanarva fimbriolata), is essential to make better management decisions. Moreover, the consequences of both pests on the sugarcane raw material quality have not yet been studied. A field experiment was performed in São Paulo State, Brazil, where sugarcane plants were exposed to pests individually or in combination. Plots consisted of a 2-m long row of caged sugarcane plants. Photosynthesis was measured once every 3 months (seasonal measurement). Yield and sugar production were assessed. The measured photosynthesis rate was negatively affected by both borer and spittlebug infestations. Photosynthesis reduction was similar on plants infested by both pests as well as by spittlebug individual infestation. Plants under spittlebug infestation resulted in yield losses and represented 17.6% (individual infestation) and 15.5% (multiple infestations). The sucrose content and the sucrose yield per area were reduced when plants were infested by multiple pests or spittlebug

Effective spacetime from multi-dimensional gravity

We study the effective spacetimes in lower dimensions that can be extracted from a multidimensional generalization of the Schwarzschild-Tangherlini spacetimes derived by Fadeev, Ivashchuk and Melnikov ({\it Phys. Lett,} {\bf A 161} (1991) 98). The higher-dimensional spacetime has $D = (4 + n + m)$ dimensions, where $n$ and $m$ are the number of "internal" and "external" extra dimensions, respectively. We analyze the effective $(4 + n)$ spacetime obtained after dimensional reduction of the $m$ external dimensions. We find that when the $m$ extra dimensions are compact (i) the physics in lower dimensions is independent of $m$ and the character of the singularities in higher dimensions, and (ii) the total gravitational mass $M$ of the effective matter distribution is less than the Schwarzshild mass. In contrast, when the $m$ extra dimensions are large this is not so; the physics in $(4 + n)$ does explicitly depend on $m$, as well as on the nature of the singularities in high dimensions, and the mass of the effective matter distribution (with the exception of wormhole-like distributions) is bigger than the Schwarzshild mass. These results may be relevant to observations for an experimental/observational test of the theory.Comment: A typo in Eq. (24) is fixe

Constraining Galileon inflation

In this short paper, we present constraints on the Galileon inflationary model from the CMB bispectrum. We employ a principal-component analysis of the independent degrees of freedom constrained by data and apply this to the WMAP 9-year data to constrain the free parameters of the model. A simple Bayesian comparison establishes that support for the Galileon model from bispectrum data is at best weak

Fluctuations and Intrinsic Pinning in Layered Superconductors

A flux liquid can condense into a smectic crystal in a pure layered superconductors with the magnetic field oriented nearly parallel to the layers. If the smectic order is commensurate with the layering, this crystal is {\sl stable} to point disorder. By tilting and adjusting the magnitude of the applied field, both incommensurate and tilted smectic and crystalline phases are found. We discuss transport near the second order smectic freezing transition, and show that permeation modes lead to a small non--zero resistivity and large but finite tilt modulus in the smectic crystal.Comment: 4 pages + 1 style file + 1 figure (as uufile) appended, REVTEX 3.

Photosynthesis, yield and raw material quality of sugarcane injured by multiple pests

Understanding sugarcane (Saccharum spp.) response to multiple pest injury, sugarcane borer (Diatraea saccharalis) and spittlebug (Mahanarva fimbriolata), is essential to make better management decisions. Moreover, the consequences of both pests on the sugarcane raw material quality have not yet been studied. A field experiment was performed in São Paulo State, Brazil, where sugarcane plants were exposed to pests individually or in combination. Plots consisted of a 2-m long row of caged sugarcane plants. Photosynthesis was measured once every 3 months (seasonal measurement). Yield and sugar production were assessed. The measured photosynthesis rate was negatively affected by both borer and spittlebug infestations. Photosynthesis reduction was similar on plants infested by both pests as well as by spittlebug individual infestation. Plants under spittlebug infestation resulted in yield losses and represented 17.6% (individual infestation) and 15.5% (multiple infestations). The sucrose content and the sucrose yield per area were reduced when plants were infested by multiple pests or spittlebug

Engineering Privacy in Public: Confounding Face Recognition

The objective of DARPA’s Human ID at a Distance (HID) program is to develop automated biometric identification technologies to detect, recognize and identify humans at great distances. While nominally intended for security applications, if deployed widely, such technologies could become an enormous privacy threat, making practical the automatic surveillance of individuals on a grand scale. Face recognition, as the HID technology most rapidly approaching maturity, deserves immediate research attention in order to understand its strengths and limitations, with an objective of reliably foiling it when it is used inappropriately. This paper is a status report for a research program designed to achieve this objective within a larger goal of similarly defeating all HID technologies

Characterising the discharge cycle of CaCl 2 and LiNO 3 hydrated salts within a vermiculite composite scaffold for thermochemical storage

Transpired solar collectors (TSC) are an efficient means of building heating but due to the demand/use mismatch their capabilities are maximised when paired with a suitable storage technology. The Hydration and/dehydration of inorganic salts provides an appropriate energy storage medium which is compatible with the air temperature provided by a conventional TSC (<70 °C). The study reports on technical appraisal of materials which are compatible with building scale energy storage installations. Two salts (CaCl2, and LiNO3) were impregnated into porous vermiculite to form a salt in matrix (SIM). Their performance during the discharge portion of the cycle at high packing density was examined using a laboratory scale reactor. Reactor and exit temperature increases were considerably lower than those predicted from first principles. Peak reactor temperature rises of only 14 °C were observed with a reduction in temperature output from this initial peak over 60 hours. Poor salt utilization resulting from deliquescence near the reactor inlet was identified as being the source of the reduced performance. Changes in reactor size, orientation and cycling between input periods of moist and dry air did not improve reactor performance. The investigation has identified that moist air transit through the packed SIM reactor column is limited to approximately 100 mm from the air inlet. This has implications for reactor design and the operation of any practical building scale installation. Predictions of building scale energy storage capabilities based on simple scaling of laboratory test considerably under estimate the volume and complexity of equipment required