Soil water use by apple trees : a thesis presented in partial fulfillment of the requirements for the Master of Agricultural Science in Soil Science at Massey University, New Zealand

The study investigated the soil water use of an unirrigated tree and an irrigated apple tree in Hawke's Bay, New Zealand in the middle of the summer of 1988/1989. A rainout shelter was used to eliminate any water inputs from both irrigation and rain to the unirrigated tree. The irrigated tree received water inputs from both irrigation and rain. The soil water content was measured by neutron probing and time domain reflectometry. The heat pulse technique was used to measure the sap-flow in the apple trunks. Both leaf water pressure potential and stomatal resistance were measured by the pressure chamber and porometer respectively. A measuring cylinder was used to monitor the apple growth during the study. The results of the water use measurements were that - the neutron probing and time domain reflectometry showed the soil water use was about 77 litres (4.3 mm) per day taken from 0 - 1900 mm depth around the irrigated tree. However soil water extraction around the unirrigated tree was only 19 litres (1 mm) per day at the beginning of the study, and no water extraction was measured from the top 1900 mm later in the study. - the heat pulse technique showed that the unirrigated tree extracted slightly more soil water than the irrigated tree. The average sap-flow measured was 66 litres per day. Probably the unirrigated tree extracted much of its water from below 1900 mm depth, or from beyond the covered area. - the amount of water use by the apple trees was similar to regional evaporation estimates obtained using the Priestley - Taylor formula, when 0.66 fractional canopy cover was assumed. The water stress monitoring showed that a pressure chamber technique was a more sensitive way to monitor ress than was porometry. e leaf water pressure potential values showed a significant difference between the irrigated and the unirrigated apple tree ring the latter part of the study. The readily available soil water storage capacity from 0 to 400 depth (the most active part of the root zone) , from 0 - 1000 mm h, and from 0 to 1900 mm, was about 36 mm, 89 mm and 170 mm actively. When there was a lack of available soil water on the oil, the root system was forced to extract soil water from deep in soil profile. The comparison of apple fruit growth showed that during the last days of the study, the apples on the unirrigated tree grew more ly than those on the irrigated tree

UV Exposed Optical Fibers with Frequency Domain Reflectometry for Device Tracking in Intra-Arterial Procedures

Shape tracking of medical devices using strain sensing properties in optical fibers has seen increased attention in recent years. In this paper, we propose a novel guidance system for intra-arterial procedures using a distributed strain sensing device based on optical frequency domain reflectometry (OFDR) to track the shape of a catheter. Tracking enhancement is provided by exposing a fiber triplet to a focused ultraviolet beam, producing high scattering properties. Contrary to typical quasi-distributed strain sensors, we propose a truly distributed strain sensing approach, which allows to reconstruct a fiber triplet in real-time. A 3D roadmap of the hepatic anatomy integrated with a 4D MR imaging sequence allows to navigate the catheter within the pre-interventional anatomy, and map the blood flow velocities in the arterial tree. We employed Riemannian anisotropic heat kernels to map the sensed data to the pre-interventional model. Experiments in synthetic phantoms and an in vivo model are presented. Results show that the tracking accuracy is suitable for interventional tracking applications, with a mean 3D shape reconstruction errors of 1.6 +/- 0.3 mm. This study demonstrates the promising potential of MR-compatible UV-exposed OFDR optical fibers for non-ionizing device guidance in intra-arterial procedures

Neutron methods for the direct determination of the magnetic induction in thick films

We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed

Artificial intelligence in studying and evaluation of otitis media by acoustic reflectometry

Abstract. Objective: Acute otitis media (AOM) is usually associated with upper respiratory tract infections and common colds, but many times it can last longer than the initial symptoms. An acoustic reflectometry device can be used to objectify the diagnostic process. The purpose of the study was to train the neural network to identify ears with symptoms of AOM using the acoustic response of the device. Methods: An acoustic reflectometry sample of 53 ears from 39 patients was collected during laryngoscopy operation from patients with recurrent ear infections. In addition to the acoustic samples, the doctor determined whether ear had visual signs of otitis media (OM) and whether there was effusion in it. These three parameters were used in the construction of feedforward neural network. Two neural network layouts were selected, one with samples of effusion-only sick ears and the other with sick ears based on other visual indications of OM, independent of effusion. Results: The sensitivity and specificity of the trained networks were about 90%. Two different groupings of samples clearly showed that diseased ears without effusion could be identified as sick with sensitivity of 80–90%, when similar ears were included in the category of sick ears. Network with sick ears with effusion as training material had a sensitivity of 20–30% identifying sick ears without effusion. The inclusion of both types of sick ears in single network caused slight drop in sensitivity and specificity compared to just one type. Conclusion: Acoustic reflectometry can detect more than just standard cases of acute otitis media, in which effusion typically occurs. An accurate neural network for identifying sick ears without effusion can be achieved with a relatively small sample size. This indicates a possibility of conducting an in-depth analysis of other diseases within the OM group or the transition between these diseases.Tekoäly otitis median tutkimisessa ja arvioimisessa akustisella reflektometrialla. Tiivistelmä. Työtarkoitus: Akuutti otitis media (AOM) yhdistetään yleensä ylempien hengitysteiden tulehduksiin ja nuhaan, mutta monesti otitis media (OM) oireet voivat kestää tulehdustilaa tai nuhaa pidempään. Akustista reflektometriaa käyttävän laitteen avulla diagnosointi prosessia voidaan tarkastella objektiivisesti. Työn tarkoitus oli opettaa neuroverkko, mikä tunnistaa AOM-oireisen korvan akustisen reflektometrin akustisesta mittauksesta. Menetelmät: Laryngoskopiaoperaation aikana kerättiin akustisella reflektometrialla otos 53 korvasta. Operaatio suoritettiin 39 potilaalle, joilla oli uusiutuvia korvatulehduksia. Akustisten näytteiden lisäksi operaation aikana lääkäri määritti visuaaliset OM-merkit ja eritteen määrän. Näitä kolmea tietoa käytettiin eteenpäin kytkeytyvän neuroverkon rakentamiseen. Kaksi neuroverkkoa rakennettiin, joissa ensimmäisessä oli pelkästään eritettä sisältävät korvat, ja toisessa kaikki visuaalisesti OM-merkit täyttävät korvat, mukaan lukien eritettä sisältävät korvat. Tulokset: Opetettujen neuroverkkojen sensitiivisyys ja spesifisyys olivat 90 % luokkaa. Kahteen ryhmään jaettu aineisto osoitti, että sairaat eritteettömät korvat voidaan tunnistaa sairaiksi 80–90 % sensitiivisyydellä, kun neuroverkolle opetetaan sekä eritteiset että eritteettömät sairaat korvat. Pelkästään eritteisiä korvia sisältävä neuroverkko tunnisti eritteettömät sairaat korvat 20–30 % sensitiivisyydellä. Eritteisten ja eritteettömien korvien käyttö samassa neuroverkossa laski sensitiivisyyttä ja spesifisyyttä verrattuna pelkkien eritteisten käyttöön. Johtopäätökset: Akustinen reflektometria voi tunnistaa muitakin tiloja kuin tyypillisen eritteisen akuutin otitis median. Pienellä näytemäärällä voidaan saavuttaa tarkka neuroverkko, mikä tunnistaa otitis median ilman eritteen läsnäoloa. Tämä viittaa mahdollisuuteen, että syvällisellä analyysillä voidaan saada lisää tietoa taudin etenemisestä tai taudin muista tiloista

Experimental demonstration of a Brillouin optical frequency-domain reflectometry (BOFDR) sensor

To measure the strain and/or temperature along an optical fiber with one-end access, a Brillouin optical frequency-domain reflectometry (BOFDR) technique is presented in this paper. It is based on detecting the spontaneous Brillouin scattering from a sinusoidally modulated pump light. Compared to the Brillouin optical frequency-domain analysis (BOFDA), this new BOFDR sensor approach presents the advantage that the measurements are free from the distorting components related to acoustic wave modulation, thus simplifying the associated data processing.This work has been supported by the projects MIUR-PON03PE_00155_1-OPTOFER and MIUR-PON03PE_00171_1-GEOGRID of the Italian government, and by the project TEC2013-47264-C2-1-R and TEC2016-76021-C2-2-R of the Spanish government

Time-Domain Reflectometry (TDR) monitoring at a lab scale of aerobic biological processes in a soil contaminated by diesel oil

This study aims to monitor the biological processes ongoing in a hydrocarbon polluted soil. The experiments were carried out at a laboratory scale by measuring the evolution of its geophysical electromagnetic parameters. Time-domain reflectometry (TDR) probes were used to measure dielectric permittivity and electrical conductivity in columns of sandy soil artificially contaminated with diesel oil (Voil/Vtot = 0.19). To provide aerobic conditions suitable for the growth of microorganisms, they were hydrated with Mineral Salt Medium for Bacteria. One mesocosm was aerated by injecting air from the bottom of the column, while the other had only natural aeration due to diffusion of air through the soil itself. The monitoring lasted 105 days. Geophysical measurements were supported by microbiological, gas chromatographic analyses, and scanning electron microscope (SEM) images. Air injection heavily influenced the TDR monitoring, probably due to the generation of air bubbles around the probe that interfered with the probe–soil coupling. Therefore, the measurement accuracy of geophysical properties was dramatically reduced in the aerated system, although biological analyses showed that aeration strongly supports microbial activity. In the non-aerated system, a slight (2%) linear decrease of dielectric permittivity was observed over time. Meanwhile, the electrical conductivity initially decreased, then increased from day 20 to day 45, then decreased again by about 30%. We compared these results with other researches in recent literature to explain the complex biological phenomena that can induce variations in electrical parameters in a contaminated soil matrix, from salt depletion to pore clogging

Inferring Power Grid Information with Power Line Communications: Review and Insights

High-frequency signals were widely studied in the last decade to identify grid and channel conditions in PLNs. PLMs operating on the grid's physical layer are capable of transmitting such signals to infer information about the grid. Hence, PLC is a suitable communication technology for SG applications, especially suited for grid monitoring and surveillance. In this paper, we provide several contributions: 1) a classification of PLC-based applications; 2) a taxonomy of the related methodologies; 3) a review of the literature in the area of PLC Grid Information Inference (GII); and, insights that can be leveraged to further advance the field. We found research contributions addressing PLMs for three main PLC-GII applications: topology inference, anomaly detection, and physical layer key generation. In addition, various PLC-GII measurement, processing, and analysis approaches were found to provide distinctive features in measurement resolution, computation complexity, and analysis accuracy. We utilize the outcome of our review to shed light on the current limitations of the research contributions and suggest future research directions in this field.Comment: IEEE Communication Surveys and Tutorials Journa