bluuebunny/crossref_metadata_2025_split huggingface dataset:
La e-experiencia de marca a través de los medios sociales y su influencia en la e-calidad de la relación y la e-fidelización. Análisis empírico en los sitios web de viajes
Authors: Sarmiento Guede José Ramón , Ferrão Filipe António José 
Published: January 2020

El objetivo principal de este artículo es verificar la relación de la experiencia web de marca a través de los sitios web organizacionales o de los medios sociales de viajes y constatar su influencia en la calidad de la relación electrónica y en la fidelización electrónica de los usuarios. Para confirmar las hipótesis, se utilizan técnicas cuantitativas de una muestra de 769 usuarios. Del modelo propuesto, podemos concluir que la experiencia de marca a través de los medios sociales de viajes es el predictor directo más importante de la calidad de la relación y de la fidelización de marca.
The main objective of this article is to verify the relationship of the brand web experience through the organizational websites or the social travel media and to verify its influence on the quality of the electronic relationship and the electronic loyalty of the users. To confirm the hypotheses, quantitative techniques were used in a sample of 769 users. From the proposed model, we can conclude that the brand experience through social travel media is the most important direct predictor of the quality of the relationship and brand loyalty.
Estudiar las posibilidades del autorretrato personal en la enseñanza secundaria.
Authors: Arcoba Alpuente María Dolores 
Published: January 2020

En este artículo se presenta una experiencia artística realizada en diez centros de enseñanza secundaria de L’Horta Nord y Camp de Morvedre (València) sobre los procesos de construcción identitaria mediante actitudes artísticas contemporáneas, en este caso, a través del videoarte. Utilizando la Investigación educativa basada en las artes (Arts Based Educational Research) se ha llevado a término la realización y posterior análisis interpretativo de todas las producciones videográficas fundamentadas en el autorretrato tradicional, por tanto, han conformado unos resultados muy interesantes que inducen a reflexionar sobre la utilización y desarrollo de estos nuevos géneros contemporáneos dentro del área de educación artística de los centros educativos. Dentro de esta investigación la creación de las nuevas narrativas audiovisuales como lenguaje artístico en el ámbito escolar abarca gran relevancia. Consideramos la utilización del vídeo como vehículo para la creación de imágenes que al mismo tiempo funciona como herramienta de trabajo imprescindible para la reflexión, indagación y análisis. Además se constituye como un procedimiento para cuestionar y criticar la imagen sistemática.
Plant Regeneration from Mature Inflorescence of Date Palm by Using Moringa Extract
Authors: Zayed Eman M. M. , Rasmia S. S. Darwesh , Hamed Khaled Abd-El 
Published: January 2020

Plant tissue culture is becoming an important technique for the massive propagation of date palm and the available source lead to the success of this process. The mature female inflorescence is a novel and available source for in vitro propagation of date palm, nowadays become needed at the large scale to usage of organic nature materials in agriculture practice which are rich in plant growth regulators as well as micro elements. This study describes in vitro plant regeneration from mature female inflorescence explants of evaluating date palm (Phoenix dactylifera L.) by using the methanol extract of Moringa oleifera leaves which has great potential to be used as a natural source of nutraceutical in micropropagation. Mature inflorescences explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations of an extract of Moringa leaves with or without add TDZ at 0.2 and 0.6 BA mg/l. Indoles, phenols, proteins, amino acids, and carbohydrates were determined. The addition of different concentrations of an extract of Moringa oleifera leaves with TDZ at 0.2 and 0.6 BA mg/l gave the highest significant average percentage of callus formation, friable callus, germination of embryos and numbers of embryos comparing with other treatments. Also, given the highest significant values of free amino acids and carbohydrates were noted in callus and embryo germination stage.
Impact of Irrigation with Saline Water on the Production of Tomato (Solanum lycopersicum) under Soilless and Traditional Techniques
Authors: Ibrahim Alaa , Elfaki Jamal 
Published: January 2020

A greenhouse experiment was carried out to evaluate the response of tomato (Solanum lycopersicum) to saline water irrigation under soilless and traditional techniques. A special fertigation technique with two different salinity levels (1 dS m-1 and 4 dS m-1) of water was used under different soilless media, namely, perlite, gravel, and pozzolana as inert media, in addition to traditional techniques. Results showed that among the three soilless substrates, perlite medium produced the highest total yields with larger fruit sizes. Furthermore, the perlite medium enabled significant savings in water, compared to gravel (-15%) and pozzolana (-20%). Moreover, the results corroborated the existing knowledge on the tolerance of tomato to brackish water irrigation, since there was no significant difference in yield of plants grown in the soil irrigated with water with salinity levels of 1.1 dSm-1 and 4-5 dS m-1. Plant biometric data revealed a better and quicker development of plants grown in the soilless media compared to those grown in the soil, even in the case of freshwater irrigation.
Biodegradation Potentials of Aspergillus sydowii and Fusarium lichenicola on Total Petroleum Hydrocarbon in an Oilfield Wastewater in Rivers State
Authors: Janet Olufunmilayo Williams, , Owhonka Aleruchi 
Published: January 2020

This study investigated the potential of Aspergillus sydowii and Fusarium lichenicola as mixed cultures in the biodegradation of Total Petroleum Hydrocarbons TPHs in oilfield wastewater. Oilfield wastewater was collected from an onshore oil producing platform and biodegradation of total petroleum hydrocarbons was investigated using standard methods. Fungi were isolated from oilfield wastewater contaminated soils obtained from the vicinity of the oil producing platform. Experimental control set-up and treatment with mixed culture of fungal isolates were periodically analyzed on days 7 and 21 intervals for total petroleum hydrocarbon degradation using Gas Chromatography (GC). The total amount of TPHs on day 1 recorded 381. 871 mg/l. The amount of TPHs on days 7 and 21 in the mixed culture of fungi was 108.975 mg/l and 21.105 mg/l respectively while TPHs in control was 342.891 mg/l and 240.749 mg/l respectively. There was a significant difference between the mixed culture and the control on days 7 and 21 at p≤0.05. The results therefore revealed actual and significant reduction of TPHs in the mixed culture. In addition, there was clearance of n-alkanes by the mixed culture. This suggests that fungi have great potentials in biodegradation of TPHs and in remediation of TPH contaminated environments.
Patterns in California Ambulance Patient Offload Times by Local Emergency Medical Services Agency
Authors: Feldmeier Madeline , Reyes Karen Patricia , Chen Crystal , Sporer Karl A. , Konik Zita , Garzón Hernando , Hsia Renee Y. 
Published: December 2024

ImportanceAmbulance offload delays are a timely and crucial issue with implications for patients, emergency medical services (EMS) agencies, hospitals, and communities. Published data on recent patterns in ambulance patient offload times (APOTs) are sparse.ObjectiveTo examine patterns in APOT by California local EMS agency and variation between and within local agencies.Design, Setting, and ParticipantsThis cohort study used APOT reports from the California EMS Authority and local EMS agencies between January 1, 2021, and June 30, 2023, to examine patterns in ambulance offload times. County-level population data were collected from the US Census Bureau to calculate mean annual offloads per 1000 population.ExposureAmbulance transport to emergency departments.Main Outcomes and MeasuresAmbulance offload volumes, mean annual offloads per 1000 population, APOT-1 (a reporting metric that includes the 90th percentile ambulance offload time and number of offloads to a specific hospital) weighted means (SDs), and APOT-1 medians (IQRs).ResultsA total of 5 913 399 offloads across 34 California local EMS agencies were analyzed. The APOT-1 weighted mean (SD) across the state was 42.8 (27.3) minutes, and the median (IQR) monthly hospital-level APOT-1 was 28.9 (14.9-46.3) minutes. Nearly one-half of local EMS agencies (16 of 34 [47.1%], accounting for 79.2% of all offloads) experienced an APOT-1 weighted mean greater than the 30-minute standard set by the state. Moreover, 20 of 33 local EMS agencies (60.6%) reported an annual APOT-1 weighted mean that was worse in 2023 than 2021.Conclusions and RelevanceIn this cohort study, approximately half of all agencies consistently reported ambulance offload times greater than the 30-minute state standard, and there was significant variation between and within agencies. These findings may spur collaborative efforts between stakeholders to determine the most effective strategies for addressing systemic issues resulting in long APOT across California.
Corrugated Horn Antennas
Authors: Gentili Gian Guido , Nesti Renzo , Pelosi Giuseppe , Selleri Stefano 
Published: December 2024

Abstract
In this work, the basic theory of circular corrugated horn antennas is presented, using easy concepts with simple mathematics. The aim is to give the reader an understanding of the fundamental electromagnetic properties of these devices and to provide a set of quantitative design tools for the electromagnetic engineer.
The wave propagation problem in corrugated waveguides is approached by approximating the field boundary conditions on the corrugation limit surface and by making further assumptions, suggested by practical considerations, with a consequent mathematical simplification of the theory. This approach has the major advantage of providing an analytical solution for the electromagnetic field, which is accurate as far as the approximate boundary conditions are valid, highlighting the most relevant features of corrugated waveguides.
The problem of radiation from corrugated horns is addressed in a similar way by choosing an approximated model sufficiently accurate for almost all practical needs. This model, the “Gaussian beam model,” has a simple analytical formulation and is rigorously treated. The final result of this approach is a set of analytical formulas relating electromagnetic properties to geometric parameters that are very useful in the design.
Then, further design aspects concerning the throat region, the phase center, and cross‐polarization are introduced and numerical methods for highly accurate analysis of corrugated horns are described, ending with some design examples.
Electromagnetic Wave Propagation
Authors: Teixeira Fernando L. , Moreira Fernando J. S. , Pereira‐Filho Odilon M. C. 
Published: December 2024

Abstract
This chapter discusses the nature of electromagnetic wave propagation. After a brief historical overview and a description of the electromagnetic frequency spectrum, plane waves are introduced as fundamental solutions to Maxwell's equations. Basic concepts such as wavelength, Poynting vector (power flux density), and phase velocity are explained in view of such waves. The transverse nature of electromagnetic waves in free space and its relation to polarization are also discussed. The chapter continues with an examination of the relation between electromagnetic waves and sources, followed by a description of spherical and cylindrical waves. Next, the nature of electromagnetic wave propagation in lossy media is considered, where concepts such as frequency dispersion and group velocity are introduced. The interaction of electromagnetic waves with obstacles is treated next by considering scattering and diffraction phenomena, and, in more detail, the reflection and transmission (refraction) of electromagnetic waves across material boundaries. This is followed by a description of guided wave propagation, and a description of surface and leaky waves. Finally, the chapter briefly explains the distinction between coherent and noncoherent waves and discusses research challenges related to the wave propagation in manmade media such as metamaterials and in natural media such as the troposphere and the ionosphere.
Radar Cross Section
Authors: Jenn David C. 
Published: December 2024

Abstract
Radar cross section (RCS) is a measure of the magnitude of the scattered electromagnetic (EM) wave from a body relative to the magnitude of the wave incident on the body. It is an indicator of the strength of an object's signal returned to a radar sensor. To many people, RCS is synonymous with stealth. Stealth technology has become an integral part of all military systems since it was first employed in the 1970s. However, RCS is just one aspect of stealth, the design philosophy that seeks to make a platform (such as an aircraft, ship, or ground vehicle) undetectable to a wide range of sensors. Recently, there has been a rapid expansion of radar sensors for commercial applications like autonomous vehicles and robotics. These applications necessitate the characterization of the RCS of a wide range of objects commonly found in the urban environment, such as cars, bicycles, and even pedestrians.
Reconfigurable Antennas
Authors: Bernhard Jennifer T. 
Published: December 2024

Abstract
High‐speed wireless systems continue to require more functionalities from antennas than can be provided by classic designs. One approach to this challenge is to develop and implement reconfigurable antennas. The goal of a reconfigurable antenna—one that can adjust its operating frequency, bandwidth, and/or radiation pattern to accommodate changing system requirements—poses significant challenges to both antenna and systems designers. This chapter first defines antenna reconfigurability, provides insight into early related historical developments, and then highlights some of the more recent advances in the area of antenna reconfiguration. Additionally, some of the barriers that still need to be overcome to arrive at realizable, fieldable technologies are discussed. These barriers include the development of reliable, cost‐effective, and mass‐manufacturable switching and tuning elements, the design of bias networks that will not interfere with antenna operation, and the continued expansion of signal processing and feedback algorithms to fully exploit this new antenna functionality.
Reflectarray Antennas
Authors: Encinar Jose A. , Martinez‐de‐Rioja Daniel , Martinez‐de‐Rioja Eduardo 
Published: December 2024

Abstract
This chapter gives an overview of reflectarray antennas, covering from their historical development to the latest applications. A reflectarray antenna consists of an array of phase‐shifter cells, which are preadjusted to generate a collimated or shaped beam, when illuminated by an external source. The chapter describes different types of reflectarray cells, analysis and design techniques, as well as some realizations for bandwidth improvement, multifrequency operation, and beam scanning. Various selected applications of reflectarray antennas in radar, imaging, and communications are described. Some of them are already commercialized as automotive radars and imaging scanners for security. Finally, some challenging examples of satellite antennas are shown, such as spaceborne interferometer radars, contoured‐beam antennas for broadcasting, large inflatable reflectarrays, multibeam antennas for satellite communications, and high‐gain antenna for data transmission in CubeSats.
Multimode Equivalent Network Representations: Recent Advances
Authors: Guglielmi Marco , Boria Vicente 
Published: December 2024

Abstract
The objective of this chapter is to describe recent advances in the multimode equivalent network (MEN) theory for the full‐wave modeling and electromagnetic simulation of waveguide junctions. This paper is the second entry in this Encyclopedia in the context of the MEN theory. Although some of the theoretical development described in this second entry can be applied also to the theory described in the first entry, it is important to note that the two contributions are complementary and that they are both valid on their own merit.
Transient Analysis
Authors: Feely Orla , Mulkeen Brian , King Justin 
Published: December 2024

Abstract
This chapter reviews the basic principles of transient circuit analysis, which is a long‐established branch of circuit theory with a wide range of applications. It examines transient behavior in linear circuits and explains the type of behavior that can occur in these circuits. It shows how this behavior can be analyzed by solving appropriate differential equations or by applying the Laplace transform. A brief discussion of transient simulation for nonlinear radio frequency (RF) circuits is also provided, showing how arbitrary frequency‐defined models may be handled via a rational model and time‐domain convolution.
Radio Reception
Authors: Zvonar Zoran 
Published: December 2024

Abstract
Multiple factors influence the radio system performance, including radio propagation, radio link design, radio receiver design, and radio network design. The focus of this section is on the key elements of the radio reception that are starting point for the radio system design.
Radio propagation addresses fundamentals of path loss prediction models, outdoor and indoor prediction models, and effects of environment and small‐scale variations resulting in multipath fading. The emphasis is on channel characterization and statistical propagation models. Radio link design part covers link budget and frequency planning. Section on man‐made noise and interference completes the list of external factors that influence radio performance. The aspects of radio receiver design include introduction to radio front‐end parameters, diversity techniques, modulation and coding, and interference suppression techniques.
Hybrid CAD Techniques
Authors: Arndt Fritz 
Published: December 2024

Abstract

Microwave components, antennas, and systems that meet the tight requirements of today's advanced wireless terrestrial and satellite‐based communication systems—in particular concerning increased specifications and performance—demand
fast
EM‐based computer‐aided design (CAD) tools yielding accurate, highly optimized components within adequately short design times. This goal makes flexible and efficient hybrid solutions desirable, which typically go beyond the design capabilities of the involved single methods. The chapter presents an overview of the state of the art of hybrid CAD mode‐matching (MM)/finite‐element (FE)/method‐of‐moments (MoM) techniques applied for the rigorous, fast CAD and optimization of waveguide components, antennas and arrays and describes recent advances. The hybrid techniques presented combine advantageously the efficiency of the MM method with the flexibility of the FE method and the efficiency and flexibility of MoM for radiating structures. Typical application examples illustrate the versatility and high efficiency of these hybrid techniques.
Integral Equations
Authors: Rao S. M. 
Published: December 2024

Abstract
In this chapter, we present simple and efficient numerical solution methods for solving several types of integral equations encountered in electromagnetic engineering problems. All these methods can be categorized into a single method popularly known as the method of moments (MOM). Initially, we present the method for simple one‐ and two‐dimensional problems and later extend the method to more complex three‐dimensional problems. Although the MOM solution technique is the most popular method for calculating radar cross section (RCS) of complex objects, it is limited by prohibitively large computational and memory requirements if attempted to use in the millimeter wave region (30–300 GHz). Lastly, in this work, a new procedure is described to estimate RCS of truly complex and practical problems and to overcome the limitation imposed by conventional MOM scheme.
Monte Carlo Simulation in Reliability
Authors: Leemis Lawrence M. 
Published: December 2024

Abstract

Simulation is a generic term used loosely in engineering, with application areas ranging from flight simulators used in cockpit design to simulated annealing used in optimization. Simulation is presented here as a mathematical and computational technique used to analyze probabilistic models. Simulation can be divided into
Monte Carlo simulation
, in which
static
models are analyzed, and
discrete‐event simulation
, in which
dynamic
models involving the passage of time are analyzed. This chapter surveys algorithms for generating random variates for simulation in the setting of a reliability application.
Piezoelectricity
Authors: Uchino Kenji 
Published: December 2024

Abstract
Certain materials produce electrical charges on their surfaces as a consequence of applied mechanical stress. The induced charges are proportional to the mechanical stress. This is called the direct piezoelectric effect and was discovered by Jacques and Pierre Curie in 1880. Materials showing this phenomenon also conversely have a geometric strain proportional to an applied electric field. This is the converse piezoelectric effect. The root of the word “piezo” means “pressure”; hence, the original meaning of the piezoelectricity implied “pressure electricity.”
Piezoelectric materials provide coupling between electrical and mechanical parameters. The material used earliest for its piezoelectric properties was single‐crystal quartz. Quartz crystal resonators for frequency control appear today at the heart of clocks and are also used in computers and mobile phones. Ferroelectric polycrystalline ceramics such as barium titanate and lead zirconate titanate exhibit piezoelectricity when electrically poled. Since these ceramics possess significant and stable piezoelectric effects, that is, high electromechanical coupling, they are capable of producing large strains/forces and hence are extensively used as transducers. Piezoelectric polymers, notably polyvinylidene difluoride and its copolymers with trifluoroethylene and piezoelectric composites combining a piezoelectric ceramic with a passive polymer, have been developed that offer a high potential. Thin films of piezoelectric materials have received attention recently because of their potential utilization in microsensors and ‐actuators.
Piezoelectricity is being extensively utilized in the fabrication of various devices such as transducers, actuators, surface acoustic wave devices, and frequency control. In this article, we discuss the piezoelectric effect, a brief history of piezoelectricity followed by present‐day piezoelectric materials that are used, and finally various potential applications of piezoelectric materials.
Intermodulation Measurement
Authors: Abuelma'atti Muhammad T. 
Published: December 2024

Abstract
Whenever a number of signals of differing frequencies pass through a nonlinear device, energy is transferred to frequencies that are sums and differences of the original frequencies, that is, intermodulation products. This article presents a simple intermodulation theory and discusses its limitations and extensions. Methods of characterizing and measuring the intermodulation performance of nonlinear devices are presented, and their merits and demerits are discussed.