Conventional Indirect Methods Research Articles

Indirect bridge modal identification enhanced by iterative vehicle response demodulation

This paper introduces a novel indirect bridge modal identification framework for extracting higher-mode bridge modal parameters. The method involves processing the vehicle response using a newly proposed iterative vehicle response demodulation technique, which separates multi-component vehicle responses while preserving the physical meaning of variables. This property is crucial for ensuring accurate and robust modal identification from vehicle responses. The feasibility of this approach is initially tested through the analysis of vehicle responses generated by numerical simulations. This analysis includes a detailed parametric study and discussions on various bridge conditions and types. Subsequently, the same methodology is applied to an experimental bridge, where structural modal parameters are extracted from the measured responses of a passing instrumented vehicle. The key contributions of this study include the development of the iterative vehicle response demodulation formulation and the ability of this method to identify modal parameters using fewer processing steps compared to conventional indirect identification methods. Results from both numerical simulations and experimental tests demonstrate that the iterative demodulation method can effectively extract higher-mode bridge modal parameters, validating the proposed framework’s effectiveness.

A novel method for ring-planet gear mesh force identification via SVD-based Kalman filter

Dynamic mesh forces are the primary vibration excitations of the planetary gear transmission systems. However, they are difficult to measure directly, and conventional indirect measurement methods are typically only applicable to specific planetary gear sets with special measuring equipment. This study proposes a more widely applicable method for identifying the mesh forces of ring-planet gear pairs by utilizing vibration signals. To this end, a ring gear dynamic model is established based on the elastic theory of the thick ring in the form of a space state system. The state vector of the model is constructed from parameters of ring gear vibration responses, while the input state vector is derived from parameters of dynamic mesh forces. A singular value decomposition (SVD)-based Kalman filter is employed to provide a stable solution for the estimation of state vector and input vector simultaneously. A mesh force indirect measurement method based on tooth fillet strain signals collected by strain gauges is adopted to evaluate the accuracy of identification results. Results of dynamic experiments conducted in a planetary gear set test rig demonstrate that compared with measured results, the proposed method can obtain acceptable estimated mesh forces of ring-planet gear pairs by using vibration signals.

Optimization of calcium carbide residue utilization for producing high‐quality calcium carbonate

AbstractIn light of the current situation where the utilization of calcium carbide slag yields low profits but holds significant potential for reducing carbon emissions, ammonium acetate was employed to leach calcium carbide slag. It also played a crucial role in regulating the products of indirect carbon dioxide carbonation when mixed with glycine and lye. Ammonium acetate's significance underscores its dual role in both the leaching and carbonation processes. This process yielded calcium carbonate with particle sizes smaller than 100 nm, with a purity of 98% and a single vaterite phase. The calcium carbide residue demonstrated an impressive CO2 uptake rate of 23.5%. Ammonium acetate exhibited an efficiency of 79.2% as a leaching agent. The ammonium acetate method demonstrated enhanced environmental friendliness and facilitated a more efficient carbon uptake rate of 23.5% compared to conventional indirect methods. Furthermore, the addition of lye, glycine, and ammonium acetate effectively extended the nucleation time of the calcium carbonate crystals and induced the formation of more vaterite intermediates with smaller particle sizes. The influence mechanism of compound additives on the carbonation reaction was revealed through kinetic analysis and molecular dynamics. This innovative approach offers a promising avenue for simultaneously treating solid waste and reducing CO2 emission. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.

Cyclic Learning-Based Lightweight Network for Inverse Tone Mapping

Recent studies on inverse tone mapping (iTM) have moved toward indirect mapping, which generates a stack of low dynamic range (LDR) images with multiple exposure values (multi-EV stack) and then merges them. In order to generate multi-EV stack(s), several large-scale networks with more than 20 M parameters have been proposed, but their high dynamic range (HDR) reconstruction and multi-EV stack generation performance were not acceptable. Also, some previous methods using cycle consistency should even have trained additional networks that are not used for multi-EV stack generation, which results in large memory for training. Thus, this paper proposes novel cyclic learning based on cycle consistency to reduce the memory burden in training. In detail, we eliminated networks used only for training, so the proposed method enables efficient learning in terms of training-purpose memory. In addition, this paper presents a lightweight iTM network that dramatically reduces the network sizes of the existing networks. Actually, the proposed lightweight network requires only a small parameter size of 1/100 compared to the state-of-the-art (SOTA) method. The lightweight network contributes to the practical use of iTM. Therefore, the proposed method based on a lightweight network reliably generates a multi-EV stack. Experimental results show that the proposed method achieves quantitatively SOTA performance and is qualitatively comparable to conventional indirect iTM methods.

Examining the Influence of Aggregate Shape Properties Measured Using Imaging Technique on the Flexural Strength of Concrete

It is known that aggregate shape properties influence the quality and performance of pavement materials. Yet, there is little information available on the effect of aggregate shape properties on the flexural strength of concrete, which is the main topic of the present study. Aggregate Image Measurement System (AIMS) was used to analyze three sizes of coarse aggregate and three sizes of fine aggregate obtained from three different sources. Portland cement concrete beams were prepared and tested for flexural strength using Universal Testing Machine (UTM) according to ASTM standards. A positive relationship with a high correlation was found between some aggregate shape properties (angularity and texture) and the flexural strength of the concrete. At the same time, an inverse relation with weak correlation was noticed between flexural strength and sphericity of coarse aggregates. Meanwhile, the 2-D form of fine aggregate showed a positive relationship with a weak correlation with flexural strength. Despite showing a similar trend of effects that shape properties have on flexural strength, the shape indices showed a better correlation with flexural strength than uncompacted void content, which is used as a measure of combined shape properties in the conventional indirect test methods. Results also suggested that the shape indices measured using the imaging technique can be a good alternative for the conventional methods.

A novel test device for the direct measurement of tensile strength of rock using ring shape sample

A novel test method is proposed in this research for determining the tensile strength of rocks and geo-materials. Using a seesaw device, two diametral tensile forces are applied to the inner surface of a ring shape specimen and consequently the ring specimen is splitted along a plane normal to the direction of applied tensile loading. A suitable formulation was derived for determining the tensile strength value using the direct ring tension specimen tested with the seesaw device. The required shape factor for the suggested tensile strength relation was obtained from the finite element analyses of ring specimen with different inner and outer diameters. The practical ability of suggested direct tensile strength measurement method was examined by performing some tensile strength experiments on tuffite rock and it was found that the results obtained from this test method is in very good agreement with two other conventional indirect tensile strength testing methods namely the Brazilian disc and compressed ring tests. Suitable geometry (i.e. inner/outer diameter ratio) was also proposed for testing the ring specimen. In addition, the fracture patterns of direct and indirect ring specimens tested with different di/do ratios were simulated and predicted using the XFEM method.

Tractography-based targeting of the ventral intermediate nucleus: accuracy and clinical utility in MRgFUS thalamotomy.

Tractography-based targeting of the thalamic ventral intermediate nucleus (T-VIM) is a novel method conferring patient-specific selection of VIM coordinates for tremor surgery; however, its accuracy and clinical utility in magnetic resonance imaging-guided focused ultrasound (MRgFUS) thalamotomy compared to conventional indirect targeting has not been specifically addressed. This retrospective study sought to compare the treatment locations and potential adverse effect profiles of T-VIM with indirect targeting in a large cohort of MRgFUS thalamotomy patients. T-VIM was performed using diffusion tractography outlining the pyramidal and medial lemniscus tracts in 43 MRgFUS thalamotomy patients. T-VIM coordinates were compared with the indirect treatment coordinates used in the procedure. Thalamotomy lesions were delineated on postoperative T1-weighted images and displaced ("translated") by the anteroposterior and mediolateral difference between T-VIM and treatment coordinates. Both translated and actual lesions were normalized to standard space and subsequently overlaid with areas previously reported to be associated with an increased risk of motor and sensory adverse effects when lesioned during MRgFUS thalamotomy. T-VIM coordinates were 2.18 mm anterior and 1.82 mm medial to the "final" indirect treatment coordinates. Translated lesions lay more squarely within the boundaries of the VIM compared to nontranslated lesions and showed significantly less overlap with areas associated with sensory adverse effects. Translated lesions overlapped less with areas associated with motor adverse effects; however, this difference was not significant. T-VIM leads to the selection of more anterior and medial coordinates than the conventional indirect methods. Lesions moved toward these anteromedial coordinates avoid areas associated with an increased risk of motor and sensory adverse effects, suggesting that T-VIM may improve clinical outcomes.

Comparison Study of Funduscopic Exam of Pediatric Patients Using the D-EYE Method and Conventional Indirect Ophthalmoscopic Methods

Purpose: The D-EYE device, a new fundoscopic smartphone lens, has demonstrated its utility in a clinical setting to detect and document ocular pathology, but has not been tested in the pediatric population. A prospective study was performed to explore the application of D-EYE in pediatric fundus examinations. Methods: Patients ages 3 - 18 years old underwent dilated fundus examinations by masked examiners using the video function of the D-EYE, while indirect ophthalmoscopy was performed by apediatric ophthalmologist. The examiners independently analyzed the D-EYE videos for the presence or absence of abnormalities, cup-to-disc (c/d) ratios and optic nerve size and color. The D-EYE video findings were compared to indirect ophthalmoscopy findings. Results: The study included 172 eyes from 87 patients. In comparing D-EYE to indirect ophthalmoscopy for detecting fundus abnormalities, the sensitivity was 0.72, specificity was 0.97, positive predictive value (PPV) was 0.77, negative predictive value (NPV) was 0.97, positive likelihood ratio (LR) was 27.8, and negative LR was 0.29. The agreement rate between the D-EYE video graders for the c/d ratio within a value of 0.1 was 97.0%. Multiple, distinct abnormalities were discovered using the D-EYE device, including nystagmus, optic nerve hypoplasia, optic disc edema, peripapillary atrophy, disc pallor, and optic disc drusen. Conclusion: Fundoscopic imaging using the D-EYE smartphone lens reliably detects the presence of fundus abnormalities and has good reliability in assessing c/d ratios. The video capability is useful in patients with nystagmus or those who are poorly compliant with the examination and allowed for effective teaching by the pediatric ophthalmologist.

One-pot titration methodology for the characterization of surface acidic groups on functionalized carbon nanotubes

Functionalization is one of the key procedures for real applications of carbon nanotubes (CNTs) as it involves the generation of the acidic functional groups on their surfaces. In these procedures, precise elucidation of these surface acidic groups is significant for the proper utilization of the functionalized CNTs. For easy characterization of the practical acidic groups on CNTs, one-pot titration methodology is developed, breaking the boundary between the conventional indirect and direct titration methods. The practical acidic functional groups including carboxylic, lactonic, and phenolic groups were successfully computed from the acid ionization constant (pKa) distribution from the direct titration of nitric acid-oxidized multi-walled CNTs by means of a one-pot titration methodology. These results were fairly identical to the results of the popular indirect titration method, showing that the developed methodology is essentially applicable for the surface characterization of acidic groups on CNTs and potentially extended to the other carbon nanomaterials.

Migration of ohmic heating electrode components into a food

Ohmic heating has an advantage over conventional indirect heating methods because heater (electrode) surfaces temperatures are comparatively lower as heat is generated within bulk fluid. Conventional ohmic heating under typical low frequency alternating current (50 or 60 Hz) could cause hydrogen and oxygen evolution due to electrolysis of water. This process could develop the electrodes decay or corrosion. Any decay or corrosion of electrodes shorten the life time and contaminate the food.in this study Concentrations of Fe, Cr, Ni, Mn, and Mo from the stainless steel electrode migrated into ohmically and conventionally treated soup were measured. migration of the major key metal ions from stainless steel measured by Atomic Absorbtion shows that Overall ohmic treatment yielded reduced migration residues of all metal ions, compared to the conventional retorting with similar electrodes. Concentrations of all metal ions migrated into food samples after ohmic treatment were far lower than dietary exposure levels so that this technique can ensure the safety and quality of food supplies.

Bayesian Framework Based Direct Reconstruction of Fluorescence Parametric Images.

Fluorescence imaging has been successfully used in the study of pharmacokinetic analysis, while dynamic fluorescence molecular tomography (FMT) is an attractive imaging technique for three-dimensionally resolving the metabolic process of fluorescent biomarkers in small animals in vivo. Parametric images obtained by combining dynamic FMT with compartmental modeling can provide quantitative physiological information for biological studies and drug development. However, images obtained with conventional indirect methods suffer from poor image quality because of failure in utilizing the temporal correlations of boundary measurements. Besides, FMT suffers from low spatial resolution due to its ill-posed nature, which further reduces the image quality. In this paper, we propose a novel method to directly reconstruct parametric images from boundary measurements based on maximum a posteriori (MAP) estimation with structural priors in a Bayesian framework. The proposed method can utilize structural priors obtained from an X-ray computed tomography system to mitigate the ill-posedness of dynamic FMT inverse problem, and use direct reconstruction strategy to make full use of temporal correlations of boundary measurements. The results of numerical simulations and in vivo mouse experiments demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images as compared with the conventional indirect method and a previously developed direct method.

A Direct Method With Structural Priors for Imaging Pharmacokinetic Parameters in Dynamic Fluorescence Molecular Tomography

Images of pharmacokinetic parameters in dynamic fluorescence molecular tomography (FMT) have the potential to provide quantitative physiological information for biological studies and drug development. However, images obtained with conventional indirect methods suffer from low signal-to-noise ratio because of failure in efficiently modeling the measurement noise. Besides, FMT suffers from low spatial resolution due to its ill-posed nature, which further reduces the image quality. In this letter, we present a direct method with structural priors for imaging pharmacokinetic parameters, which uses a nonlinear objective function to efficiently model the measurement noise and utilizes the structural priors to mitigate the ill-posedness of FMT. The results of numerical simulations and in vivo mouse experiments demonstrate that the proposed method leads to significant improvements in the image quality.

Production of lacZ inducible T cell hybridoma specific for human and mouse gp10025-33 peptides

Event Abstract Back to Event Production of lacZ inducible T cell hybridoma specific for human and mouse gp10025-33 peptides Gal Cafri1, Adi Sharbi-Yunger1, Esther Tzehoval1, Zoya Alteber1, Meir Azulay1, Yosi M. Gozlan1 and Lea Eisenbach1* 1 Weizmann Institute of Science, Israel The key event in T cell activation is the recognition of a peptide bound to major histocompatibility complex (MHC) molecules on the surface of antigen presenting cells (APCs). The enormous pool of peptides displayed on MHC makes it almost impossible to detect a given peptide-MHC complex on the surface of APCs by using conventional indirect methods. On the other hand, direct recognition of a selected peptide by the TCR results in generation of intracellular signals leading to initiation of the primary stages of T cell activation. To facilitate measurement of T cell activation and to enable identification of individual clones, β-galactosidase (lacZ) inducible CD4+ and CD8+ T cell hybrids were developed. Previous studies showed that heterologous Escherichia coli β-galactosidase (lacZ) gene, under control of the IL-2 entire enhancer region or the nuclear factor in activated T cells (NFAT) element alone, is specifically induced in transfected and activated T cells. Thus, activation of transfected T cells, results in synthesis of both IL-2 and lacZ gene products. Moreover, since the lacZ remains sequestered within the activated cells, chromogenic or fluorogenic substrate enables measurement of an activating event in a single T cell. Generation of the hybrids is relatively easy and allows maintenance in culture and the lacZ assay provides a rapid, sensitive and non-radioactive method for measuring T cell activation. In this study we isolated T cells from Pmel-1 mice and generated a lacZ inducible CD8+ T cell hybridoma. Keywords: hybridoma, tcr, gp100 Melanoma Antigen, Antigen Presentation, activation Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune receptors and signaling Citation: Cafri G, Sharbi-Yunger A, Tzehoval E, Alteber Z, Azulay M, Gozlan YM and Eisenbach L (2013). Production of lacZ inducible T cell hybridoma specific for human and mouse gp10025-33 peptides. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00586 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Jun 2013; Published Online: 22 Aug 2013. * Correspondence: Prof. Lea Eisenbach, Weizmann Institute of Science, Rehovot, Israel, lea.eisenbach@weizmann.ac.il Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gal Cafri Adi Sharbi-Yunger Esther Tzehoval Zoya Alteber Meir Azulay Yosi M Gozlan Lea Eisenbach Google Gal Cafri Adi Sharbi-Yunger Esther Tzehoval Zoya Alteber Meir Azulay Yosi M Gozlan Lea Eisenbach Google Scholar Gal Cafri Adi Sharbi-Yunger Esther Tzehoval Zoya Alteber Meir Azulay Yosi M Gozlan Lea Eisenbach PubMed Gal Cafri Adi Sharbi-Yunger Esther Tzehoval Zoya Alteber Meir Azulay Yosi M Gozlan Lea Eisenbach Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Direct Estimation of Kinetic Parametric Images for Dynamic PET

Dynamic positron emission tomography (PET) can monitor spatiotemporal distribution of radiotracer in vivo. The spatiotemporal information can be used to estimate parametric images of radiotracer kinetics that are of physiological and biochemical interests. Direct estimation of parametric images from raw projection data allows accurate noise modeling and has been shown to offer better image quality than conventional indirect methods, which reconstruct a sequence of PET images first and then perform tracer kinetic modeling pixel-by-pixel. Direct reconstruction of parametric images has gained increasing interests with the advances in computing hardware. Many direct reconstruction algorithms have been developed for different kinetic models. In this paper we review the recent progress in the development of direct reconstruction algorithms for parametric image estimation. Algorithms for linear and nonlinear kinetic models are described and their properties are discussed.

Use of Raman spectroscopy to determine the site occupancy of dopants in BaTiO3

Chemical doping is one of the major methods by which the properties of BaTiO3 are modified to induce various device characteristics. Doping strategies are generally separated into iso- and alio-valent (donors and acceptors) and into A- and B-site species within the perovskite structure. The A1g octahedral breathing mode at ∼800 cm−1 in BaTiO3 is Raman inactive for compositions with single B-site species. However, this mode becomes Raman active if more than one B-site species is present, including titanium vacancies, VT′′′′. Moreover, the relative intensity of the A1g breathing mode is qualitatively related to the concentration of the species replacing Ti in the B-site. This article illustrates some clear cases where the A1g octahedral breathing mode can be utilized to verify the site occupancy of dopants in BaTiO3 when used in conjunction with more conventional indirect methods such as x-ray diffraction (Vegard’s Law) and dielectric measurements as a function of temperature.

A determination method of pristine multiwall carbon nanotubes in rat lungs after intratracheal instillation exposure by combustive oxidation–nondispersive infrared analysis

This paper describes a method for determination of multiwall carbon nanotubes (MWCNTs) in rat lungs after intratracheal instillation exposure. The MWCNTs were quantitatively decomposed to CO 2 by combustive oxidation and were then determined by non-dispersive infrared analysis. Samples were pretreated by acid digestion, muffle ashing and in situ preheating to remove interferences due to coexisting biological carbon from the lung tissue sample, while preserving the MWCNTs as in its their original form. The preservation was confirmed by transmission electron microscopic observation of the pretreated samples of exposed lung tissues and by the fact that the recoveries of MWCNTs spiked to the lung tissues were close to 100%. The detection limit for MWCNTs obtained by the proposed method was 0.30 μg and the repeatability as expressed by the relative standard deviation was 5.6% ( n = 4). The method was sufficiently sensitive and precise to apply to real samples of rat lung to investigate the in vivo persistence of intratracheally instilled MWCNTs. To our knowledge, this is the first report of this type of sample pretreatment and direct determination of pristine MWCNTs without modification or tagging. Conventional indirect methods use tagging with other compounds or metal impurities in the CNTs for detection, and the detachment of these tags can increase uncertainties in the determination of the CNTs. The tags can also change how the CNTs persist in vivo, which can lead to an incorrect understanding of the persistence of pristine CNTs in vivo.

Milk fouling at direct ohmic heating

Direct ohmic heating (Joule’s heating) is a technology to warm up the food using an electric energy where electric current is passed through a material which gets heated by virtue of its electrical resistance. Advantages over conventional indirect heating methods are speed and uniformity of heating. On the other side, the direct ohmic heating of liquid foods has some problems, for example corrosion and deposits creation on electrodes (fouling). The present research on fouling concentrates upon the effects of material and surface properties of electrodes, and upon the effect of power frequency. This work evaluates influence of material (stainless steel, TiN and graphite electrodes), flow rate, electric current density (at constant frequency 50 Hz) and temperature (in a limited temperature range 65–75 °C), upon the fouling of skimmed milk. Results prove that the stainless steel electrodes are the worst while the graphite electrodes, where no fouling was observed, are the best, thus confirming the significant role of corrosion and electrochemical phenomena. The paper analyzes also another phenomenon typical for direct ohmic heating and it is an inner overheating of the formed fouling layer, representing a risk of overburning. Theoretical results show that the most intensive overheating occurs at relatively very thin deposit layers, depending upon the specific electrical conductivity of deposits.

Direct Localization of Subthalamic Nucleus Supplemented by Single-Track Electrophysiological Guidance in Deep Brain Stimulation Lead Implantation: Techniques and Clinical Results

Background/Aims: In subthalamic nucleus (STN) deep brain stimulation (DBS) lead implantation, it is still controversial whether it is more appropriate to employ indirect or direct methods in magnetic resonance imaging (MRI)-based tentative targeting and to select single- or multiple-track recording in electrophysiological definitive targeting. The efficacy of single-track electrophysiological recording through direct targeting was compared with the conventional indirect targeting methods in light of the identified STN thickness and clinical results. Methods: The identified mean STN thickness, pre- and 6-month postoperative Unified Parkinson’s Disease Rating Scale (UPDRS), dose change of L-dopa and dopaminergic agonists were compared in indirect (midcommissural point-based, 44 procedures) and direct (image-based, 44 procedures) targeting methods. Results: The identified mean STN thickness was significantly greater in the group employing direct methods. For evaluation of the UPDRS, a significant scale improvement was noted in part 2 OFF for both groups. Significant scale improvements occurred in parts 3 and 4 in the group employing the direct method. Both groups revealed significant L-dopa dose reduction with the tendency towards a greater reduction in the group employing the direct method. Conclusion: MRI-based direct targeting supplemented by single-track recording could be justified as a standard for DBS lead implantation to achieve better clinical results.

Applying Radial Acoustic Amplitude Signals To Predict Intervals of Sand-Stuck Tubing

Summary The reuse of existing well bores is a cost-saving technique used by oil and gas producers in mature fields. This process usually requires the removal of tubing and packers to allow the well to be deepened or sidetracked. The tubing removal process is often made difficult when the tubing is stuck inside the casing because of mechanical binding or binding caused by dehydrated mud or sand in the annulus between the tubing and casing. Conventional direct and indirect methods of finding the stuck point(s) along an interval of tubing, such as free-point indicator tools or acoustic attenuation measurements, have proved themselves useful in finding the point(s) where the tubing is stuck. However, when the sticking is caused by uncompacted sand that has entered the annular space between the tubing and casing, these conventional stuck-pipe indication methods are often inconclusive or misleading. Technological advancements in the design and development of slim, 11116-in. outside diameter (OD), radial cement bond tools allow the application of a new measurement to find sand-stuck tubing intervals. These tools provide up to six independent, closely spaced acoustic attenuation measurements distributed radially around the tool body. When the recording operation is performed inside the tubing, the increased sensitivity of these tools to sound attenuation, as compared with conventional omnidirectional amplitude signals, allows sand intervals along the outside of the tubing to be distinguished from intervals where little or no sand is present. This information is used to select the best depth to sever or back-off the free tubing in order to reduce the interval length and expense associated with the washover process required to remove the remaining tubing from the wellbore. An overview of conventional stuck-pipe recovery techniques is provided here, along with a brief explanation of applicable acoustic technology. A case study of a South Louisiana well is presented to demonstrate the application and illustrate the cost savings which can be gained by use of this very new technology.

Effect of Temperature and Power Frequency on Milk Fouling in an Ohmic Heater

Ohmic heating has an advantage over conventional indirect heating methods because heater (electrode) surfaces temperatures are comparatively lower as heat is generated within bulk fluid. However, it is difficult to sustain this advantage over time. As soon as fouling takes place, electrode temperature starts rising and eventually it becomes higher than bulk fluid temperature. In this study, we have analysed the changing temperature profile and its impact on the fouling process during thermal processing of milk in a cylindrical ohmic heater. Furthermore, the impact of power supply frequency on the corrosion of electrode surfaces and in turn on fouling has also been investigated. The use of a 10 kHz power supply is observed to reduce corrosion and result in less fouling compared with a 50 Hz mains power supply.