Propagation Medium Research Articles

The effect of different IBA doses on rooting in soft-wood cuttings of rootstock candidate sweet cherry, sour cherry and mahaleb genotypes

This study was carried out to investigate the effect of different IBA (Indole Butyric Acid) concentrations on rooting in soft-wood cuttings of rootstock candidate sweet cherry, sour cherry, and mahaleb genotypes in a plastic greenhouse with underfloor heating and mist propagation of Black Sea Agricultural Research Institute. 500, 1000, and 2000 ppm IBA doses were applied to the soft-wood cuttings taken in june. Perlite was used as propagation medium and rooting medium was disinfected with methyl bromide before planting. The study was planned according to a randomized plot design with three replications and 20 cuttings in each replication. The rooting rate (%), number of roots (piece), number of branching roots (piece), and root length (mm) were investigated. The highest rooting ratio of 59 % (08 K 056) was obtained from the 1000 ppm IBA application, while the lowest rooting ratio of 22.50% (55 K 104) was obtained from the 1000 ppm IBA application.

Numerical analysis of a one-dimensional nonlinear wave scattering at a contact interface with damageable adhesion and unilateral contact

The nonlinear scattering of a longitudinal harmonic plane wave, induced by a contact interface, is investigated numerically, using a model that combines damageable adhesion and unilateral contact. This novel approach captures the smooth transition between a perfectly bonded interface and a disbonded clapping interface, also referred to as a kissing bond. This is achieved through an RCCM (Raous, Cangémi, Cocu and Monerie) contact law, where exceedance of the elastic limit in tension triggers the generation of damage and a progressive reduction of the tensile interface stiffness until zero, i.e. equivalent to unilateral contact. This RCCM law is implemented in a 1D finite difference model where the contact interface is defined between a semi-infinite domain and a rigid wall. Since the nonlinear scattering is only dependent on the interface law, damping in the propagation medium is not considered. The reflected wave is post-processed to obtain the nonlinear signature of the interface through the evolution of the normalized DC, fundamental and second harmonic components, as a function of the normalized frequency and the interface load. This analysis provides useful insights for understanding the interface response and shows that the nonlinear signature contains information on the different parameters of the RCCM law, as well as on the damage state of the interface. These encouraging results provide insight and guidance for the non-destructive evaluation of contact interfaces and adhesive joints using non-linear acoustics.

Seismoacoustic Analysis of the Large Surface Explosion Coupling Experiment Using a Large-N Seismic Array

ABSTRACT Seismoacoustic signals at local distance (<∼10 km) are widely used as important constraints on source parameters for near-surface events, yet the seismoacoustic wave generation and energy partitioning are not fully understood. Spatially dense sensors could provide observations in high resolution to capture the full wavefield for better understanding wave propagation and improving source estimation. Recently, spatially dense observations of the local seismoacoustic wavefield produced by a pair of 1-ton surface explosions have been recorded using a large-N seismic array. This large-N array consists of 446 geophones and covers an area of approximately 2×2.5 km2. The two surface explosions occur at the same location but at different times with different atmospheric conditions. Both seismic and air–ground coupled acoustic waves from the two surface explosions are well observed. Analyses of signals recorded by the large-N seismic array show different acoustic wave speed and amplitude for the two explosions. A strong spatial variability in acoustic wave speed and amplitude for each explosion is also observed. The observations suggest the important role of local atmosphere state on wave propagation and source estimation and demonstrate how the use of a large-N capability can improve characterization of the propagation medium and source.

An ultrasonic coda wave method for stress loss prediction in pre-stressed strongly heterogeneous multi-layer structures

A coda wave method is proposed to predict the stress loss of pre-stressed strongly heterogeneous multi-layer structures using ultrasonic testing. The method is centered on the basis that ultrasound can be multiply scattered and form the decaying coda waves in the strongly heterogeneous multi-layer structure. As the stress loss of the pre-stressed structure can alter the inter-layer contacting state and the mechanical strain of the propagation media, the signal features subject to the stress loss can be amplified in the process of multiply scattering and encoded in the coda wave. A theoretical model is developed to evaluate the stress of the muti-layer structure using the relative change in velocity of the ultrasonic coda wave. Experimental testing is performed on a five-layer pre-stressed mockup structure made of three different materials with vastly different mechanical and physical properties. Model parameters are obtained using testing data. An independent set of testing data is used to validate the developed model. The accuracy of the model is compared with an existing reference model. Results show that the proposed method can predict the stress accurately and outperform the reference model.

Spatiotemporal Behavior of an Extremely Small Seismic Swarm in Pyrenean Foreland, France

ABSTRACT During the large-N MAUPASACQ passive seismic experiment in the foreland of the western Pyrenees (southwest France), an unusual swarm-type seismic sequence was serendipitously recorded in a normally quiet area. Thanks to the density of the deployment and the proximity of all events, it was possible to relocate the hypocenters with a very good relative accuracy through template matching, cross-correlation phase picks, and double-difference algorithm. The four-month seismic activity consists of more than 600 events with local magnitudes ranging between −1.4 and 2.1, clustered in an extremely small volume, and rooted at 4 km depth. The sequence can be divided in two phases of similar durations and event occurrence rates, but of different magnitude–frequency distributions. The presence of an asperity is suggested by the relative abundance of stronger events during the second phase. Fine mapping suggests a small but clear geographic offset of a few tens of meters between the events of the two phases and a very slow migration suggesting a process involving fluids. Changes in the correlation matrices and waveforms of late arrivals at a specific station are also observed, arguing either (and again) for migration of the hypocenters or for changes in the propagation medium between the two phases. The geographical coincidence with the repeated observation of hydrogen leaks on the surface, almost above the swarm, suggests a connection through channels that could carry fluids.

PENENTUAN JENIS MEDIA TERHADAP EFEKTIVITAS PERTUMBUHAN JAMUR TRICHODERMA HARZIANUM

This study aims to determine a suitable medium for the growth Trichoderma harzianum. The treatments tested were rice media (M1), bran media (M2), corn media (M3), potato media (M4), and rice husk mixed media (M5). The parameters observed in this study were the quality test of conidia density using a microscope and haemacytometer, macroscopic observation of the media for 7 days and microscopic observation of the media to evaluate the media that had the best effectiveness as a medium for propagation of Trichoderma harzianum. The initial isolate of Trichoderma harzianum used had a conidia density of 2,9x109conidia/ml. The results showed that the propagation of Trichoderma harzianum in various media affected the macroscopic, microscopic and conidia density changes of Trichoderma harzianum. Trichoderma harzianum can grow on all treatment media. The bran media is the medium with the highest conidia density compared to other media.

Ultra-broadband direct dielectric spectroscopy of liquids using a calibrated Microwave-Fluidic vertical Two-Wire sensor with Bi-Material 3D printed chamber

A novel ultra-broadband dielectric spectroscopy technique for liquids is introduced. A two-wire transmission line sensor is employed in which the liquid-under-test comprises fully the propagation medium ensuring high sensitivity and direct permittivity measurement. A vertical wire arrangement is exploited fed by a double-sided parallel stripline with a microstrip interface and no bandwidth-limiting impedance transformation. A seal-integrated flex-rigid 3D-printed liquid container is developed for robust assembly. A raw measured propagation constant correction is proposed through setup calibration using only one reference liquid, which can be air. Sensor operation and design aspects are discussed in detail and an exemplary sensing setup is developed for experimental validation. A set of liquids is characterized within a three-decade bandwidth up to 42 GHz and fitted into a relaxation model along with a comparison against industry-standard broadband open-coax sensor captured data. The conducted study and error analysis certified the performance of the proposed setup.

Tissue culture of gerunggang (Cratoxylum arborescens (Vahl) Blume): multipurpose native species of Indonesian peatland

Gerunggang (Cratoxylum arborescens (Vahl) Blume) is a tree native to Indonesian peatlands that has great potential as an alternative fiber-producing species for the pulp and paper industry because it is adaptable and does not have the potential to disrupt local ecosystems. The species also contains important anti-cancer compounds for the pharmaceutical industry. These industries require large quantities of raw materials to meet their needs, which cannot be met by the supply of conventional plant seedlings. Tissue culture is one of the propagation biotechnologies that can be used as an alternative to provide more efficient germplasm. In this study, we developed a protocol for gerunggang propagation using tissue culture technique. The results showed that the combination of 1 mg/l 6-benzylamino purine (BAP) and 0.5 mg/l naphthalene acetic acid (NAA) in Murashige & Skoog media provided the fastest bud break time (2 weeks before the first subculture), with the highest shoot initiation (3.0 ± 0.2 cm), and after 4 weeks of incubation, the highest auxiliary shoot elongation (7.4 ± 0.1 cm). The significant effect of this hormone concentration also increases the nodule multiplication coefficient (NMC), which is 7.5. In vitro root response on the same propagation medium showed good growth with an average root length of 4.8 ± 0.2 cm. Acclimatization of plantlets was successful under ex vitro conditions and resulted in good growth after 2 and 3 months in the greenhouse. The advantage of applying the tissue culture method to gerunggang is that it can produce about seven times more seedlings from one explant in about 4 weeks. These results will be very useful for further research in the field and require a more intensive and comprehensive study.

Estimation of Probabilistic Characteristics of Reception of Frequency-Effective Signals during Propagation along a Radio Line with Fog

A model of a radio line with fog, which is used to represent distortions of complex envelopes of digital signals because of the absorbing and dispersive properties of the propagation medium, has been considered. It is shown that with an increase in the frequency band of digital signals and with an increase in their order of manipulation (when using frequency-efficient signals), the influence of these distortions leads to energy losses in relation to propagation in free space. The quantitative estimation of energy losses for the digital signals used in applications with multi-position phase, quadrature-amplitude, and amplitude-phase manipulations and for a radio line with fog with a variation of its parameters has been carried out. It has been shown that for signals with multiposition phase and amplitude-phase manipulations (the frequency efficiency coefficient of the signals is 4 bits/s/Hz), the energy losses reach 3.5 and 1.0 dB, respectively.

Recovery of spatially varying acoustical properties via automated partial differential equation identification.

Observable dynamics, such as waves propagating on a surface, are generally governed by partial differential equations (PDEs), which are determined by the physical properties of the propagation media. The spatial variations of these properties lead to spatially dependent PDEs. It is useful in many fields to recover the variations from the observations of dynamical behaviors on the material. A method is proposed to form a map of the physical properties' spatial variations for a material via data-driven spatially dependent PDE identification and applied to recover acoustical properties (viscosity, attenuation, and phase speeds) for propagating waves. The proposed data-driven PDE identification scheme is based on ℓ1-norm minimization. It does not require any PDE term that is assumed active from the prior knowledge and is the first approach that is capable of identifying spatially dependent PDEs from measurements of phenomena. In addition, the method is efficient as a result of its non-iterative nature and can be robust against noise if used with an integration transformation technique. It is demonstrated in multiple experimental settings, including real laser measurements of a vibrating aluminum plate. Codes and data are available online at https://tinyurl.com/4wza8vxs.

Determination of the best culture medium for establishment, propagation and conservation in vitro of citrus rootstocks

In micropropagation and in vitro conservation various nutrient media have been used for regeneration of citrus rootstocks. In this respect, the present study was conducted to define, among three culture media, one of common use (MS) and two developed for arboreal species (RMAN and WPM), the best formulation for the establishment, propagation and conservation in vitro. Plantlets from 10 citrus rootstocks grown in the three media were micropropagated and conserved in vitro for 18 months, during which they were submitted to three subcultures at six-month intervals. The RMAN and WPM formulations provided the highest seed germination percentages, but the analysis of the morphogenetic response during the subcultures revealed that the composition of RMAN resulted in loss of the regenerative capacity of the explants in the second subculture. As occurred for RMAN, there was reduced development of the plants cultivated in MS with each new subculture. The plants grown in WPM, maintained or increased their regenerative capacity during the subcultures. Among the media studied, WPM was the most efficient for micropropagation and in vitro conservation, while the RMAN limited the in vitro germination of the rootstocks.

Acoustic Wave Reflection in Water Affects Underwater Wireless Sensor Networks.

The phenomenon of acoustic wave reflection off fluid-solid surfaces is the focus of this research. This research aims to measure the effect of material physical qualities on oblique incidence acoustic attenuation across a large frequency range. To construct the extensive comparison shown in the supporting documentation, reflection coefficient curves were generated by carefully adjusting the porousness and permeability of the poroelastic solid. The next stage in determining its acoustic response is to determine the pseudo-Brewster angle shift and the reflection coefficient minimum dip for the previously indicated attenuation permutations. This circumstance is made possible by modeling and studying the reflection and absorption of acoustic plane waves encountering half-space and two-layer surfaces. For this purpose, both viscous and thermal losses are taken into account. According to the research findings, the propagation medium has a significant impact on the form of the curve that represents the reflection coefficient, whereas the effects of permeability, porosity, and driving frequency are relatively less significant to the pseudo-Brewster angle and curve minima, respectively. This research additionally found that as permeability and porosity increase, the pseudo-Brewster angle shifts to the left (proportionally to porosity increase) until it reaches a limiting value of 73.4 degrees, and that the reflection coefficient curves for each level of porosity exhibit a greater angular dependence, with an overall decrease in magnitude at all incident angles. These findings are given within the framework of the investigation (in proportion to the increase in porosity). The study concluded that when permeability declined, the angular dependence of frequency-dependent attenuation reduced, resulting in iso-porous curves. The study also discovered that the matrix porosity largely affected the angular dependency of the viscous losses in the range of 1.4 × 10-14 m2 permeability.

Acoustic characterization of the seabed with a single-element time-reversal mirror

Motivated by the 2012 Florida Straits Noise Interferometry Experiment, this paper investigates a time-reversal-based approach to acoustic remote sensing of the ocean. The signal processing mimics operation of a physical time-reversal mirror. The input data for the simulated time-reversal mirror can be obtained using either a compact, broadband sound source or cross-correlation of the diffuse noise recorded by spatially separated receivers. Low-frequency sound propagation is considered over ranges that are large compared to the water depth. The approach exploits the notion that the “best” focusing of the backpropagated time-reversed signal occurs at the “right point,” when the backpropagation takes place in the same propagation medium as the one, where the data have been acquired. Various metrics of the focusing quality are considered. A combination of spatial and temporal characteristics of the focus is proposed that leads to a robust and unique solution of the geoacoustic inverse problems considered for a single-element passive time-reversal mirror. Inputs with rather low signal-to-noise ratio prove acceptable, which is particularly important in the passive remote sensing context.

Tissue culture and rapid propagation technology for Gentiana rhodantha.

Gentiana rhodantha is a perennial herb of the genus Gentiana (Tourn.) L. This study was novel in establishing a regeneration system of G. rhodantha using young leaves as explants on the Murashige and Skoog (MS) medium supplemented with different plant growth regulators (PGRs). The roots, stems, and leaves of G. rhodantha were used as explants. The effects of the optimal explant disinfection method, type of explant used, concentrations of PGRs added to the culture media on tissue culture, and rapid propagation of G. rhodantha were studied. The results showed that the optimal disinfection method for stems and roots consisted of disinfection using 75% ethanol for 50 s, followed by 4% sodium hypochlorite (NaClO) for 10 min. The optimal disinfection technique for leaves consisted of disinfection using 75% ethanol for 50 s, followed by 4% NaClO for 8 min. Root explant was the most suitable for inducing the callus of G. rhodantha on the MS medium supplemented with different PGRs. The optimal conditions for callus induction included 1.0 mg/L 6-benzylaminopurine (6-BA) and 0.5 mg/L α-naphthalene acetic acid (NAA). The callus induction rate using the root explant reached 94.28%. MS supplemented with 2.0 mg/L 6-BA and 0.1 mg/L NAA was the optimal medium for inducing adventitious shoots from the callus of G. rhodantha. The best medium for propagation and plantlets strengthening was MS supplemented with 0.8 mg/L 6-BA and 0.3 mg/L NAA, and the propagation index was 8.62. MS supplemented with 0.3 mg/L 3-indolebutyric acid was the best culture medium for inducing the rooting of adventitious buds, with the maximum rooting rate reaching up to 100%.

Minimum Variance Distortionless Response—Hanbury Brown and Twiss Sound Source Localization

Sound source target localization is an extremely useful technique that is currently utilized in many fields. The Hanbury Brown and Twiss (HBT) interference target localization method based on sound fields is not accurate enough for localization at low signal-to-noise ratios (below 0 dB). To address this problem, this paper introduces Minimum Variance Distortionless Response (MVDR) beamforming and proposes a new MVDR-HBT algorithm. Specifically, for narrowband signals, the inverse of the correlation matrix of the sound signal is calculated, and a guiding vector is constructed to compute the MVDR direction weights. These direction weights are then used to weight the correlation function of the HBT algorithm. Subsequently, the MVDR-HBT algorithm is extended from narrowband signals to broadband signals. As a result, the directivity of the HBT algorithm is optimized for wide- and narrowband signals, resulting in improved localization accuracy. Finally, the target localization accuracy of the MVDR-HBT algorithm is analyzed through simulation and localization experiments. The results show that the MVDR-HBT algorithm can accurately determine the direction of a sound source, with localization errors at different positions that are smaller than those produced by HBT. The localization performance of MVDR-HBT is considerably better than that of HBT, further verifying the simulation results. This study provides a new idea for target localization within an acoustic propagation medium (air).

Statistical Characteristics of the Temporal Spectrum of Scattered Radiation in the Equatorial Ionosphere

On the basis of the solution of the space-time characteristic system by the method of geometric optics using symbolic calculations, analytical and numerical simulation of the propagation of the ordinary and extraordinary radio waves in the conducting equatorial ionospheric plasma was made considering the anisotropy of plasma irregularities and non-stationary nature of propagation medium. Broadening of the spectrum and the displacement of its maximum contain velocity of a turbulent plasma flow and parameters characterizing anisotropic plasmonic structures. Statistical moments of both radio waves do not depend on the absorption sign and are valid for both active and absorptive random media. Temporal pulsations and conductivity of a turbulent ionospheric plasma have an influence on the evaluation of the spectrum-varying propagation distances travelling by these waves. The new double-humped effect in the temporal spectrum has been revealed for the ordinary wave varying anisotropy coefficient and dip angle of stretched plasmonic structures. From a theoretical point of view, the algorithms developed in this work allow effective modelling of the propagation of both radio signals in the equatorial conductive ionospheric plasma, considering the external magnetic field, inhomogeneities of electron density in-homogeneities, as well as non-stationary.

Toponymic restoration and media text as a marker of urban identity crisis

The modern media text is considered as one of the markers of the urban identity crisis. Since the 1960s there has been an active social movement for the preservation of cultural monuments in Irkutsk. The importance of historical toponyms for the city identity is generally recognized in the professional and cultural sphere. This provided an opportunity to manifest the theme of toponymic restoration. The wave of partial toponymic restoration in historical Russian cities in the 1990s was completely ignored by the Irkutsk authorities, and there were just a few cases of opportunistic renaming of godonyms beyond it. In the contemporary crisis processes, media acts through media texts as identifiers, crisis markers, informants, conflict producers, the space of crisis manifestations and the medium of conflict propagation.

Evaluation of Effectiveness on Some Vibration Isolation Methods for Existing Buildings and Structures from Vibrodynamic Effects, Propagating in Soil Environment

The paper presents calculations of various design schemes for vibration isolation of a building with a reinforced concrete frame from a source of vibrodynamic exposure located outside it. It is noted that in most studies, the maximum value of the velocity of vertical vibrations of the foundation or soil in front of it is used as a criterion for the risk of damage to load-bearing building structures. The main factors that determine the risk of damage to structures are identified. These include the engineering and geological conditions of the soil at the base of the affected foundations, the degree of damage to the building, the type and design of the building or structure, the vibration frequency, the duration of the vibration, the distance to the vibration source, the type of vibration source, the material of the structure and the type of foundation. Based on the analysis of factors that determine the risk of damage to structures, the parameters of a building or structure that are least sensitive to vibrodynamic effects and have greater operational reliability are identified. It should be with a frame made of reinforced concrete or steel, not damaged, located on foundations of pile-racks in strong, low-moisture coarse sands or hard clays. The proposed design schemes for vibration isolation are mainly based on one of the vibration damping mechanisms in the soil medium – scattering on inhomogeneities. The finite element method has been used as the main tool for theoretical research. The ground medium has been considered as an elastic inertial array bounded by non-reflecting boundaries. The reliability of its application for calculating the development of dynamic processes in the system “oscillation source – propagation medium – oscillation receiver” has been confirmed by verification based on data from small-scale laboratory experiments. The use of the finite element method (FEM) makes it possible to take into account the spatial variability of soil conditions, the properties of materials, the design features of buildings and structures, the magnitude, direction and point of application of the dynamic load, as well as to model and optimize various vibration protection schemes. Seven variants of vibration isolation have been considered: the device of an inertial slab on the surface of the soil medium between the vibration source and the building, the installation of a vertical screen from gas-filled cylinders under pressure, a combination of these methods, the installation of a pile field in the soil medium, the reinforcement of the columnar slab foundations of the building with micropiles, the installation of a ribbed slab on the surface soil environment between the source and receiver of oscillations, the device of a reinforced concrete cage around the foundation-source of oscillations. The effectiveness of each method of vibration isolation has been evaluated by the damping coefficient K, a parameter showing how many times the speed of vertical oscillations of the building foundation decreases. Among the above methods of vibration isolation, two most effective options have been identified: in the form of a horizontal inertial slab of reinforced concrete on the surface of a soil mass (4.5-fold reduction in the rate of vertical vibrations), and a vertical barrier made of pressurized gas-filled cylinders (reduction in the rate of vertical vibrations by 3.32 times).

Effect of enzymatic hydrolysis and nitrogen on Saccharomyces cerevisiae β-glucan production from Manihot utilissima and Maranta arunadinacea waste

This experiment utilised cassava (Manihot utillissima) and arrowroot (Maranta arunadinacea) wastes as the medium of propagation of Saccharomyces cerevisiae to produce β-glucan. The amyloglucosidase hydrolysed the waste, followed by fermentation in the nitrogenous medium by S. cerevisiae. The β-glucan pellet was extracted using 2% NaOH alkaline solution at 90°C for 5 hours, followed by a series of centrifugation processes. The highest glucose concentration from hydrolysis resulted from adding 57.5 mg amyloglucosidase enzyme for arrowroot waste with 95.93% conversion and 50 mg enzyme for cassava waste with 64.70% conversion. The highest amount was obtained for producing S. cerevisiae by adding 4.75 g peptone to all samples. The optimum number of cells was obtained at 1.61 x 108 colonies at t = 48 hours for arrowroot waste and 8.55 x 107 colonies at t = 48 hours for cassava waste. For β-glucan production, the highest number was obtained by using 3.99 g of peptone for cassava waste with a yield of 1.20% and by using 4.75 g of peptone for arrowroot waste with a yield of 1.23%. For β-glucan pellet, the highest number was 1.77 g L-1 (0.18 % b/v) from cassava waste medium and 1.91 g L-1 (0.19% b/v) from arrowroot waste. Mutant cells in the Yeast Extract–Peptone–Glycerol (YPG) medium produced 6.56 g L-1 (0.66% b/v) β-glucan pellet, while wild-type cells in the similar medium produced 1.84 g L-1 (0.18% b/v).

Channel Characteristics for Diffusive Molecular Communications in a Spherical Shell

Diffusive molecular communication (DMC) is a bio-mimicking communications paradigm that exploits the Brownian motion of dedicated information carrying molecules for signal transmission. The characteristics of the communication channel in a DMC system heavily depends on the transmitter and receiver mechanisms, on the medium of propagation and its boundaries, and on the way they interact with the molecules. In this work, we investigate the DMC channel in a spherical shell, with inner and outer surfaces which may be partially or perfectly absorptive, or reflective, where either of the boundary surfaces can be considered as the DMC receiver. These geometry and boundary conditions can be used to model a variety of practically relevant scenarios, which are investigated in detail. We derive the general parametric solution of the partial differential equation for this case and provide, for the first time in the literature, expressions for the resulting channel response. We verify the results of our analysis numerically via particle based simulations.