Vertical Source Research Articles

Research on electromagnetic field characteristics of rotating-magnet based mechanical antenna through the earth

Conventional low-frequency electromagnetic wave (LFEM) transmitting antennas are enormous in size, which limits the application of LFEM in underground space. Rotating-magnet Based Mechanical Antennas can realize the miniaturization of low-frequency antennas, which is expected to bring new possibilities for underground electromagnetic detection or ground penetration communication. Firstly, this paper establishes a synthetic field method for solving the electromagnetic field of a rotating permanent magnet in the air-earth cross-domain case. The method equates the magnet as an orthogonal superposition of vertical and horizontal dipole sources, and the phase difference between vertical and horizontal dipole sources is 𝜋/2. Based on the half-space theory of multilayer planar media, the quasi-analytical solution of the electromagnetic field of the magnetic dipole in the case of air-earth trans dimensionality can be found by superposition. Secondly, based on the finite element numerical model, the trans-earth propagation characteristics of the electromagnetic field excited by the rotating permanent magnet across the air-earth dual domain are studied. At the same time, the radiation characteristics in the rotating plane of the permanent magnet are also studied. Again, this paper systematically investigates the influence of parameters such as earth conductivity, emission frequency, and propagation distance on the electromagnetic field propagation. Finally, the principle prototype is developed and experiments are carried out. The results show that the finite element numerical model established in this paper is correct, the experimental results are consistent with the theoretical values, and a field strength signal of 0.9 nT can be received at 20 m. The research work in this paper lays the foundation for the future use of mechanical antennas for electromagnetic detection and ground penetration communication.

Observations of HONO and its precursors between urban and its surrounding agricultural fields: The vertical transports, sources and contribution to OH

The insufficient study on vertical observations of main atmospheric reactive nitrogen oxides (NO2 and HONO) posed a great challenge to evaluate their intertransport between urban and agricultural areas, and to further learn the atmospheric nitrogen chemistry and the atmospheric oxidation capacity at high altitudes. A stereoscopic measurement campaign (satellite remote sensing, hyperspectral unmanned aerial vehicle (UAV) remote sensing and MAX-DOAS observation) was performed in a typical inland city Hefei and its surrounding agricultural fields from June to October 2022. Average aerosol vertical profiles exhibited a Gaussian shape above 100 m with maximum values of 0.67 km−1 and 0.55 km−1 at 300–400 m layer at Anhui University (AHU) and Changfeng (CF), respectively. The distinct layered structure was mainly attributed to regional transport. Average H2O and NO2 vertical profiles all showed a Gaussian shape and an exponential shape at AHU and CF, respectively. Moreover, the diurnal evolution of H2O profiles performed one peak and bi-peak patterns at AHU and CF, respectively, whereas the diurnal evolution of NO2 at two stations all exhibited bi-peak patterns attributed to vehicle emissions. Average HONO vertical profiles showed an exponential shape and a Gaussian shape at AHU and CF, respectively. Higher HONO (> 0.05 ppb) above 1.0 km at 14:00–16:00 was observed at CF. The transport flux analysis showed that the northern transport flux always larger than southern transport flux for aerosol and H2O. The maximum northern transport fluxes appeared at 300 m and surface for aerosol and H2O, respectively. It indicated that surrounding agricultural fields was an important source of atmospheric H2O of city. The southern transport flux was larger than northern transport flux for NO2, with a maximum net transport flux of 9.20 ppb m s−1 at 100 m. It demonstrated that NO2 transported from urban areas was an important source of NO2 in agricultural fields. For HONO, the southern transport flux was larger than northern transport flux under 100 m, whereas it was opposite above 100 m. It indicated that the HONO distributed at high altitudes at agricultural fields had potential to enhance the atmospheric oxidation capacity of urban area. The net horizontal transport fluxes of HONO of our defined cropland were 5.25 μg m−2 s−1 and -3.65 μg m−2 s−1 during non-fertilization and fertilization periods, respectively. It indicated that the cropland could obviously export HONO to surrounding atmosphere during the fertilization period. Deducing the contribution of direct emission, heterogeneous process was a major source of HONO at urban and agricultural areas. The average surface conversion rate of NO2-to-HONO (CHONO) was 0.01467 h−1, and this value decreased with the increase of height at urban station. While average surface CHONO was 0.0322 h−1 at agricultural fields, which was ~1.2–2.8 times higher than that at urban area. The CHONO at agricultural fields significantly increased with the increase of height. The average CHONO at 1.0 km was ~2.0–3.6 times higher than that at surface. That suggested that the heterogeneous process was the main HONO source at high altitudes at CF, and this process obviously correlated with aerosol and H2O. The higher OH production from HONO (P(OH)HONO) occurred at 0–200 m and 100–400 m with averaged values of 0.31 ppb h−1 and 0.39 ppb h−1 at AHU and CF, respectively. The high P(OH)HONO above 1.0 km at CF from September to October was strongly correlated with high O3 (> 80 ppb). This study emphasized the importance of the stereoscopic of HONO on the analysis of its distribution, evolution, source and atmospheric oxidizing contribution.

See no isotropy, hear no isotropy: Perceived distance anisotropy in auditory space

The aim of the present study was to investigate whether the tendency to perceive vertical distances as larger than horizontal ones, called the anisotropy of perceived distance, exists in the auditory modality, too. We performed two experiments in which participants (16+20) had a task to match distances of two sound sources, positioned on horizontal and vertical axes, on three egocentric distances. Besides that, in the second experiment, we varied the head moving towards a sound source (with and without) and sound dispersion around the head (with or without a box-like frame around the head). Results showed that participants managed to differentiate sound source distances, but the effects of head moving (proprioceptive information) and sound dispersion around the head were not obtained. Finally, results showed differences in matched distances between two directions. Distances of the vertical sound source were systematically perceived as larger than physically equal horizontal ones, which coincide with findings from previous studies, related to visual or proprioceptive distance estimates.

Vertical and Horizontal Dipole Source Powered Broadband Wide Beamwidth Antenna

Vertical and Horizontal Dipole Source Powered Broadband Wide Beamwidth Antenna

Comparison study of RF/analog and linearity performance of dual material gate graphene source vertical TFET (DMG-GR-VTFET) and single material gate GR-VTFET

This paper investigates the comparative feature of Graphene Source Single Material Gate Vertical Tunnel FET (SMG-GR-VTFET) and Graphene Source Double Material Gate VTFET (DMG-GR-VTFET) on DC, analog/RF and linearity applications using Sentaurus TCAD simulator. The results show that both devices outperforms in DC characteristics, including ambipolar current, subthreshold swing (SS), ION/IOFF ratio etc The study focuses on important figures of merit (FOMs) such as transconductance (gm), output conductance (gd), cut-off frequency (ft), second-order transconductance (gm2), third-order transconductance (gm3), VIP2, and VIP3, which are all improved due to high mobility of graphene leads to improved band-to-band tunneling. The observed ION is 5.2 × 10−4 (1.1 × 10−3 A/μm), IOFF is 1.439 × 10−13 (2.28 × 10−16A/μm) and ION/IOFF ratio of 3.613 × 109 (4.824 × 1012) for SMG-GR-VTFET (DMG-GR-VTFET), respectively. It is seen that maximum gm is 2.96 × 10−3 (2.59 × 10−3 S μm−1) and cut-off frequency (ft) values of 1.1 × 1011 (1.85 × 1011 Hz) for SMG-GR-VTFET (DMG-GR-VTFET), respectively. Regarding the Linearity parameter VIP2 value is 2.71 V (0.99 V), respectively, for SMG-GR-VTFET (DMG-GR-VTFET). These results suggest that Graphene Source Vertical Tunnel FET is an excellent choice for analog and high-frequency applications.

The Tools and Parameters to Consider in the Design of Power Transformer Cooling Systems

Transformers are the most important elements of electric power systems. Many conditions must be met for power transformers to work properly. One of them is a low operating temperature. This condition will be met if the transformer cooling system is properly designed. One of the components of a cooling system is insulating liquid. The heat transfer coefficient α of liquid determines its ability to cool the transformer. The higher its value, the more effectively the liquid transfers heat to the environment. This article describes the influence of the position of the heat source, which is usually in the windings of the transformer, on the coefficient α value of the insulating liquid. The vertical and horizontal positions of the heat source were analyzed. The coefficient α was analyzed at different points of the heat source. The tests were carried out for mineral oil and various esters. Heat transfer coefficient measurements were carried out for various surface heat loads of the heat source. It has been proven that, in the case of a horizontal heat source, the coefficient α has a value several dozen percent higher than in the case of a vertical source. It has been proven that the coefficient α has different values in different places of the heat source. Regardless of the location, the highest value of the coefficient α occurred in the lower part of the heat source.

Vertical greening systems serve as effective means to promote pollinators: Experimental comparison of vertical and horizontal plantings

To counteract the ongoing decline of pollinators, we need innovative and effective promotion strategies. Urban areas often function as pollinator refugia, but lack of open spaces can limit promotion measures. This scarcity in open surfaces requires rethinking the conventional flower bed. Can green walls, planted with pollinator-friendly plants, provide an alternative and attractive food source for wild and managed pollinators?We compared pollinator-friendly vertical greening systems covering approximately 6 m2 with identically planted, adjacent horizontal beds consisting of wild perennials and cultivated plant varieties at two different test sites in Baden-Württemberg, Germany. With a total of 92 planting observations and more than 2,800 single plant genera observations, we documented 12,963 pollinators and their individual plant preferences over a two-year period.While our results show no differences in the total attractiveness across all pollinators between vertical systems and horizontal plantings, honey bees had a highly significant preference for the horizontal plantings, while wild bees preferred the vertical systems. Pollinator visits increased with the height of the vertical systems, indicating that pollinators will find such vertical sources and that there are advantages to higher plantings above foot traffic. These results suggest that vertical systems are highly attractive spaces for flower visitors, especially for bumble bees and other wild bees, when planted with appropriate blooming plants and thus an innovative means to promote pollinators where horizontal open spaces are limited.

Study on design and calculation method of borehole heat exchangers based on seasonal patterns of groundwater

The vertical closed-loop ground source heat pumps (GSHPs) utilize the ground as a heat sink. In areas where the groundwater is abundant with strong seasonal fluctuation, the flow rate and water table control the heat transfer rate of borehole heat exchangers (BHEs) and the thermal balance of the energy storage rock mass (ESRM). Current design focuses on the balance between rates of heat dissipation to and extraction from subsurface during operation seasons, but the energy carried by groundwater in other seasons is not utilized. This study proposes that thermal imbalance should be allowed during GSHP operation, which can be balanced off by appropriately utilizing the heat replenishment by groundwater in other seasons, achieving thermal balance year-round. A new approach to calculate BHE heat transfer rate, energy replenishment by groundwater, and annual energy budget of ESRM based on seasonal groundwater fluctuation was derived. The annual energy default and temperature deviation charts of ESRM were applied to predict whether and when the thermal balance would be restored. A case study of single heating condition showed that the thermal balance may be restored very soon after the heating period or in the flooding season 3–4 months later, depending on the groundwater pattern.

Analysis and Experiment on the Limitations of Static and Dynamic Transaural Reproduction with Two Frontal Loudspeakers

By duplicating the binaural pressures of an actual source, transaural reproduction with two frontal loudspeakers is expected to recreate a virtual source in arbitrary direction. However, experiments indicated that in static transaural reproduction, the perceived virtual source is usually limited to the frontalhorizontal plane. The reasons for this limitation, as guessed, are that, in static reproduction, the dynamic cues for front-back and vertical localisation are incorrect, and the high-frequency spectral cues are unstable with head movement. To validate this hypothesis, the variations of ITD (interaural time difference) caused by head turning in both static and dynamic transaural reproductions are analysed. The results indicate that dynamic reproduction is able to create appropriate low-frequency ITD variations, and the static transaural reproduction is unable to do so. Psychoacoustic experiments are conducted to compare virtual source localisation in static and dynamic reproductions. The results indicate that dynamic reproduction is able to recreate the front, back, and vertical virtual source for low-pass stimuli below 3 kHz, while for full audible bandwidth stimulus, appropriate low-frequency dynamic cue and unstable high-frequency spectral cues in dynamic reproduction result in two splitting virtual sources.

Assessment of vertical characterization and potential sources of aerosols in different altitude layers: Combined application of MAX-DOAS observation and the 3D-CWT model

Vertical distribution is essential for understanding the regional transport sources of pollutants accumulated at different altitudes. We investigate aerosol extinction coefficient (AEC) profiles based on ground-based multi-Axis differential optical absorption spectroscopy measurements from August 2020 to June 2021 in Ningbo, East China. AEC vertical structures can be classified into three groups: decreasing with height (51.2%), well-mixed (2.4%), and inverse structures (46.4%), which can be explained by long-range transport, the planetary boundary layer heigh, and temperature inversion. Except in the winter, the vertical profile of the AEC typically extends to higher altitudes, which suggests the accumulation, secondary formation, or long-range transport of aerosols at higher altitudes. The three-dimensional concentration weighted trajectory (3D-CWT) model is utilized to elucidate not only altitudinal atmospheric layers in which aerosol transport occurs, but also the potential source areas of aerosols at multiple air mass arrival altitudes. The 3D-CWT model results indicate the long-range transport of aerosols, mainly through backward air mass trajectories within layers 1 (0–500 m) and 2 (500–1000 m). The potential source areas of aerosols at lower altitudes are mainly distributed in the North China Plain. At air mass arrival altitudes exceeding 600 m, the sources likely to affect aerosols in Ningbo are both land-sourced and marine-sourced (including the East China Sea, Yellow Sea, and the marginal sea between Korea and Japan) air flows. At different air mass arrival altitudes, the estimated contributions of long-range transport to aerosols are approximately 6% (200 m), 11% (600 m), and 18% (1000 m). Our findings provide a scientific basis for revealing different aerosol vertical structures and assessing long-range transport contributions in coastal urban areas.

Report on the comment on the paper “The effects of vertical and horizontal sources on heat transfer and entropy generation in an inclined triangular enclosure filled with non-Newtonian fluid and subjected to magnetic field, Powder Technolgy 364(2020) 924-942”

Report on the comment on the paper “The effects of vertical and horizontal sources on heat transfer and entropy generation in an inclined triangular enclosure filled with non-Newtonian fluid and subjected to magnetic field, Powder Technolgy 364(2020) 924-942”

Distribution, sources, and health risk assessment of VOCs/SVOCs in soils obtained from petrochemical-contaminated sites in Guangzhou, a subtropical coastal megacity in southern China

Investigation and analysis of the soil contamination characteristics of legacy petrochemical sites is the basis for safe land reuse. Volatile/semivolatile organic compounds (VOCs/SVOCs) are a group of mutagenic, carcinogenic, and teratogenic substances that can induce leukemia, brain tumors, asthma, and a variety of other cancers through oral ingestion, dermal exposure, and/or inhalation. This study was designed to explore the horizontal and vertical distribution characteristics, sources, and health risks of VOCs/SVOCs in different operational areas of an abandoned petrochemical enterprise site in Guangzhou City. The survey assessed the presence and amounts of 12 VOCs/SVOCs across 522 soil samples. Measurements were conducted using a combination of purge and trap-gas chromatography and mass spectrometry (P&T-GC-MS). The investigation revealed that the total content of the 12 compounds was 69798.7 μg kg−1, with an average value of 5816.6 μg kg−1. The highest benzene content was 10900 μg kg−1, with an average value of 462.5 μg kg−1, and the maximum value exceeded this average by 2.7-fold. According to the horizontal distribution, VOCs/SVOCs were mainly concentrated in the oil delivery console, storage tank area, oil refining area, and fire pumping stations. Depending on the vertical distribution, pollutants were generally distributed in the plain fill layer, with a downward trend in the muddy silt and silt layers. The source apportionment of VOCs/SVOCs was analyzed and discussed with correlation analysis and a positive matrix factorization (PMF) model in this study. The source analysis results showed that a mixture of petroleum, solvent, and coal sources, solvent sources, and traffic sources were the main sources of VOCs/SVOCs, and their contribution rates to VOCs/SVOCs were 17.7%, 70.0% and 12.3%, respectively. The health risk assessment showed that 8 carcinogenic VOCs/SVOCs carry potential carcinogenic risks for children and adults. This study can provide data support and a judgment basis for the redevelopment of contaminated sites, determination of pollution responsibility and effective management of soil pollution.

Effectiveness of vertical error budget model for portable multi-beam echo-sounder in shallow water bathymetric survey

With the increasing availability of portable survey equipment and platforms, hydrographic data acquisition now offers a diverse range of device options and installation methods. Tailoring the mounting and installation of hydrographic survey devices to fit the boat or platform dimensions has become common practice. The use of portable equipment is essential, given the wide selection of combined options available in the market. Consequently, sensor offsets and device performance differ for each survey conducted, necessitating the constant verification of accuracy performance.This paper examines the capabilities of portable multibeam echosounder (MBES) deployments on various types of survey boats. The investigation focuses on error budget modeling and field tests. A model is developed to estimate the propagated uncertainty resulting from different sources of measurement uncertainties. The model primarily considers vertical sources of error in MBES surveys, as they have the most significant impact on hydrographic data quality. To validate the model, field tests are conducted at two different locations using different boat and device configurations. The results demonstrate that the modeled uncertainties align with the measured standard deviations, particularly in the Pramuka area, where the standard deviation of data acquired at the widest beam angle of ±60° is 0.25m, close to the predicted value of 0.28m. However, in the Patimban area, the model overestimates the uncertainty, predicting 0.27m compared to the measured standard deviation of 0.17m.

A 3D frequency-domain electromagnetic solver employing a high order compact finite-difference scheme

Three-dimensional (3D) electromagnetic (EM) modeling is an important tool for geophysical applications. In EM induction methods the modified Helmholtz equation is often used to describe scattered or residual electric fields in three dimensions. Throughout this paper, a high order compact finite difference scheme for the solution of that equation for vertical magnetic dipole source (VMD) is presented. The approximation of the residual electric field intensity using a fourth order compact finite difference (FD) discretizer is achieved with the solution of a block linear system, the coefficient matrices are large and sparse with a particular structure, implying the application of a matrix-free Krylov subspace method for an efficient numerical solution. The proposed solver is being examined using a number of test problems in uniform and non-uniform grid spacing where numerical and analytical solutions for the homogeneous half-space cases are being compared.

A highly sensitive vertical plug-in source drain high Schottky barrier bilateral gate controlled bidirectional tunnel field effect transistor.

In this article, we propose a highly sensitive vertically plug-in source drain contacts high Schottky barrier based bilateral gate and assistant gate controlled bidirectional tunnel field Effect transistor (VPISDC-HSB-BTFET). It can achieve much more sensitive forward current driving ability than the previously proposed High Schottky barrier source/drain contacts based bilateral gate and assistant Gate controlled bidirectional tunnel field Effect transistor (HSB-BTFET). Silicon body of the proposed VPISDC-HSB-BTFET is etched into a U-shaped structure. By etching both sides of the silicon body to form vertically plug-in source drain contacts, the source and drain electrodes are plugged into a certain height of the vertical parts of both sides of the U-shaped silicon body. Thereafter, the efficient area of the band-to-band tunneling generation region near the source drain contacts is significantly increased, so as to achieve sensitive ON-state current driving ability. Comparing to the mainstream FinFET technology, lower subthreshold swing, lower static power consumption and Higher Ion-Ioff ratio can be achieved.

Knowledge flows and innovation: a pseudo-panel approach

ABSTRACT This study investigates whether the effect of vertical and horizontal knowledge sources affect technological innovation for a sample of firms in 10 European countries. The empirical analysis is based on a unique dataset extracted from the Community Innovation Survey for the period 2002 to 2012. Results, using a pseudo-panel approach at country-industry level, reveal that vertical knowledge from suppliers strongly affects both product and process innovation, while knowledge flows from clients influence in particular product innovation. Finally, horizontal knowledge flows from competitors appear to have an effect on process innovation. These findings are validated with an instrumental variable approach using Lewbel’s technique to internally generate reliable instruments, when external ones are not suitable. Overall, results seem to suggest the need for ad-hoc policies to foster knowledge flows among firms in different phases of the production process to boost their innovative capacity both for products and processes.

Inhomogeneous antibiotic distribution in sediment profiles in anthropogenically impacted lakes: Source apportionment, fate drivers, and risk assessment

Antibiotic residues in lake ecosystems have been widely reported; however, the vertical distribution of antibiotics in lake sediment profiles have rarely been examined. This study systematically revealed the vertical distribution pattern, sources, and risks of antibiotics in sediments of four typical agricultural lakes in central China. Nine of 33 target antibiotics were detected with a total concentration range of 39.3–18,250.6 ng/g (dry weight), and the order of average concentration was erythromycin (1447.4 ng/g) > sulfamethoxazole (443.7 ng/g) > oxytetracycline (62.6 ng/g) > enrofloxacin (40.7 ng/g) > others (0.1–2.1 ng/g). The middle-layer sediments (9–27 cm) had significantly higher antibiotic detected number and concentration than those in the top layer (0–9 cm) and bottom layer (27–45 cm) (p < 0.05). Correlation analysis showed that significant relationships existed between antibiotic concentrations and the octanol–water partition coefficients (Kow) of antibiotics (p < 0.05). Redundancy analysis indicated that Pb, Co, Ni, water content, and organic matter (p < 0.05) jointly affected the distribution of antibiotics in sediment profiles. Risk assessment showed that the highest potential ecological and resistance selection risks of antibiotics occurred in the middle-layer sediments, and oxytetracycline, tetracycline, and enrofloxacin had the most extensive potential risks in the sediment profiles. Additionally, the positive matrix factorization model revealed that human medical wastewater (54.5%) contributed more antibiotic pollution than animal excreta (45.5%) in sediment. This work highlights the inhomogeneous distribution of antibiotics in sediment profiles and provides valuable information for the prevention and control of antibiotic contamination in lakes.

Vertical array signal recovery method based on normalized virtual time reversal mirror

Focusing on the vertical array source signal recovery method, aiming at the estimation deviation caused by environment mismatch in the engineering application of virtual time reversal mirror technology, this paper proposes the normalized virtual time reversal technology through theoretical derivation and analyzes the performance of the virtual time reversal technology under the change of environment and signal-to-noise ratio through simulation. Finally, the practicability of the normalized virtual time reversal method and the effectiveness of model correction are verified through experimental data. The data processing results show that the source level estimation error of vertical array based on normalized virtual time reversal algorithm is less than 5.2dB. In the experimental environment of this paper, the correlation of signal spectral structure recovered by this method is about 5% higher than that by the traditional method.

Trends of patents on wind power electric generator

This article discusses the patents related to wind energy to identify technologies, their degree of development as well as their applications and trends. The research was carried out with Google Patents, which delivered more than 700 results from worldwide intellectual property offices. The terms Wind &amp; Power &amp; Electric &amp; Generator were reviewed, analyzed, and classified. Patents were identified with a significant focus on Machines, Structure, Applications in Vehicles, Methods, and Control, that apply the concept of a horizontal axis wind turbine – HAWT (93.8%), followed by a vertical axis wind turbine - VAWT (5.6%) and incipient development in non-rotational systems (static) - WS (0.6%). Finally, a summary of the functional components of a wind energy system is included as a conceptual model for the development of a vertical axis wind source (VAWS).

Study on vertical line source Green's function for hydrodynamic calculations of ocean structures in water with ice cover

The numerical calculation of panel integrals associated with the Green's function satisfying water surface condition with ice cover is the basis for the boundary element method (BEM) to solve hydrodynamic problems of ocean structures in ice regions. In order to simplify the calculation process and reduce the time consuming, the vertical line source representing the analytical integral of ice-covered Green's function over vertical line segment is firstly derived in this paper. Then a semi-analytical quadrature, which accumulates a series of vertical line sources distributing along the horizontal direction, can be derived for the panel integral. In the numerical implementation, the asymptotic analysis method is employed to eliminate the singularity at zero point of the denominator, variable substitution is performed to treat the integral at infinite and approximate polynomials are introduced to evaluate the Bessel functions. Through the calculations of vertical line and panel integrals of Green's function and its derivatives, the analytical expression of vertical line source is proved to be accurate and more efficient than the normal numerical quadrature. Based on this, a BEM program is developed and applied in the hydrodynamic calculations of submerged structures with ice cover. The computed results are found to be in excellent agreement those of the validated BEM based on point source, which further verifies the reliability and practicability of utilization of vertical line source.