Liquid-Liquid Equilibrium of Sesame Fatty Acid (Ethyl and Methyl) Ester + Glycerol + Ethanol/Methanol Mixtures at Different Temperatures.

This study aimed to investigate the liquid-liquid equilibrium (LLE) behavior of sesame fatty acid ethyl ester (FAEE) and methyl ester (FAME) in combination with glycerol and the co-solvents ethanol and methanol. FAEE and FAME were produced through the transesterification of mechanically extracted and purified sesame oil, using potassium hydroxide (KOH) as a homogeneous base catalyst. The reactions were conducted in ethanol and methanol to produce FAEE and FAME, respectively. Post-reaction, the products were separated and purified, followed by an analysis of the LLE behavior at 313.15 K and 323.15 K under atmospheric pressure (101.3 kPa). The experimental process for the miscibility analysis utilized a jacketed glass cell adapted for this study. Miscibility limits or binodal curves were determined using the turbidity-point method. Tie lines were constructed by preparing mixtures of known concentrations within the two-phase region, which allowed the phases to separate after agitation. Samples from both phases were analyzed to determine their composition. This study revealed that higher temperatures promoted greater phase separation and enhanced the biodiesel purification process. The NRTL model effectively correlated the activity coefficients with the experimental data, showing good agreement, with a root-mean-square deviation of 3.5%. Additionally, the data quality was validated using Marcilla's method, which yielded an R2 value close to 1. Attraction factors and distribution coefficients were also calculated to evaluate the efficiency of the co-solvents as extraction agents. The findings indicated higher selectivity for methanol than for ethanol, with varying degrees of distribution among the co-solvents. These results offer significant insights into enhancing biodiesel production processes by considering the effects of co-solvents on the LLE properties of mixtures, ultimately contributing to more efficient and cost-effective biodiesel production.

Effect of Storage Time on the Physical, Chemical, and Rheological Properties of Blueberry Jam: Experimental Measurements and Artificial Neural Network Simulation.

Reversible data hiding (RDH) is crucial in modern data security, ensuring confidentiality and tamper-proofness in various industries like copyright protection, medical imaging, and digital forensics. As technology advances, RDH techniques become essential, but the trade-off between embedding capacity and visual quality must be heeded. In this paper, the relative correlation between the pixel's local complexity and its directional prediction error is employed to enhance an efficient RDH without using a location map. An embedding process based on multiple cumulative peak region localization (MCPRL) is proposed to hide information in the 3D-directional prediction error histogram with a lower local complexity value and avoid the underflow/overflow problems. The carrier image is divided into three color channels, and then each channel is split into two non-overlapping sets: blank and shadow. Two half-directional prediction errors (the blank set and the shadow set) are constructed to generate a full-directional prediction error for each color channel belonging to the host image. The local complexity value and directional prediction error are critical metrics in the proposed embedding process to improve security and robustness. By utilizing these metrics to construct a 3D stego-Blank Set, the 3D stego-shadow Set will be subsequently constructed using the 3D blank set. The proposed technique outperforms other state-of-the-art techniques in terms of embedding capacity, image quality, and robustness against attacks without an extra location map. The experimental results illustrate the effectiveness of the proposed method for various 3D RDH techniques.

Cherenkov light emission in molecular radiation therapy of the thyroid and its application to dosimetry.

Numerical experiments based on Monte Carlo simulations and clinical CT data are performed to investigate the spatial and spectral characteristics of Cherenkov light emission and the relationship between Cherenkov light intensity and deposited dose in molecular radiotherapy of hyperthyroidism and papillary thyroid carcinoma. It is found that Cherenkov light is emitted mostly in the treatment volume, the spatial distribution of Cherenkov light at the surface of the patient presents high-value regions at locations that depend on the symmetry and location of the treatment volume, and the surface light in the near-infrared spectral region originates from the treatment site. The effect of inter-patient variability in the tissue optical parameters and radioisotope uptake on the linear relationship between the dose absorbed by the treatment volume and Cherenkov light intensity at the surface of the patient is investigated, and measurements of surface light intensity for which this effect is minimal are identified. The use of Cherenkov light measurements at the patient surface for molecular radiation therapy dosimetry is also addressed.

A prevalence study in Guadalajara, Mexico, comparing tuberculin skin test and QuantiFERON-TB Gold In-Tube.

BACKGROUND: Tuberculosis (TB) is a prevalent disease throughout the world. The extent of TB illness in childhood is not clear; recent data shows that 10-20% of the cases are found in children under 15 years old. In 2017, 1 million children developed the disease, of which 9% were co-infected with HIV. METHODS: A cross-sectional study that analyzed 48 children diagnosed with HIV-infection in Guadalajara, Mexico. The tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube test (QFT) were performed and compared to diagnose latent TB infection (LTBI). RESULTS: The average age was 9 years old (± 4), with an age range of 1-16 years; the 6-12-year-old group predominated with 50% of cases. 27 patients (56%) were male; 83% had received the BCG vaccination and 23% had a history of being contacts of TB cases. In the study, 40 patients (83%) were without immunosuppression; seven (15%) with moderate immunosuppression, and only one patient had severe immunodeficiency. Overall, 3 of the 48 children (6.2%) had a positive TST, while 8 out of 48 (16.6%) had a positive QFT. The concordance between the two tests was 89.6% (43/48) with Kappa = 0.5 (95% CI, 0.14-0.85). CONCLUSIONS: The QFT test represents an opportunity in the diagnosis of LTBI, particularly in pediatric HIV- patients. This is the first study that compares the two tests (TST and QFT) in children with HIV-infection in Guadalajara, Mexico.

GAMOS/GEANT4 simulation and comparison study of X-ray narrow-spectrum series at the national Secondary Standard Dosimetry Laboratory of Morocco.

This study aimed to simulate the X-ray Irradiator narrow-spectrum series and compare the results with experimental and recommended values in ISO standards. X-Ray beam qualities of N-40 to N-300 were established experimentally at the national Secondary Standard Dosimetry Laboratory (SSDL) of Morocco in purpose of calibrating radiation protection- level. The variations between the first half-value layer (1st HVL) and the second (2nd HVL) for experimental were within 5%. Also, homogeneity coefficients h were mostly between 0.75 and 1 according to ISO. GAMOS Monte Carlo code was used to simulate the radiation quality of narrow-spectrum series between N-40 to N-150. All 1st HVL, 2nd HVL, and h simulation values were compare with experimental and ISO values. In MC codes and GAMOS, there is no direct way to generate the X-ray spectrum if we do not have details of the X-ray tube geometry, dimensions and materials. Therefore, Institute of Physics and Engineering in Medicine report number 78 was used to generate the X-ray spectrums in purpose to test this method accuracy. The simulation results for the 1st HVL and 2nd HVL showed a good agreement with experimental data and with ISO 4037-1:1996 given values. Also, the comparison results showed that most of the homogeneity coefficients are within the ISO standard range.

Evaluation of the Simultaneous Analysis of Organic and Inorganic Gunshot Residues Within a Large Population Data Set Using Electrochemical Sensors*, †.

The increasing demand for rapid methods to identify both inorganic and organic gunshot residues (IGSR and OGSR) makes electrochemical methods, an attractive screening tool to modernize current practice. Our research group has previously demonstrated that electrochemical screening of GSR samples delivers a simple, inexpensive, and sensitive analytical solution that is capable of detecting IGSR and OGSR in less than 10 min per sample. In this study, we expand our previous work by increasing the number of GSR markers and applying machine learning classifiers to the interpretation of a larger population data set. Utilizing bare screen-printed carbon electrodes, the detection and resolution of seven markers (IGSR; lead, antimony, and copper, and OGSR; nitroglycerin, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite) was achieved with limits of detection (LODs) below 1 µg/mL. A large population data set was obtained from 395 authentic shooter samples and 350 background samples. Various statistical methods and machine learning algorithms, including critical thresholds (CT), naïve Bayes (NB), logistic regression (LR), and neural networks (NN), were utilized to calculate the performance and error rates. Neural networks proved to be the best predictor when assessing the dichotomous question of detection of GSR on the hands of shooter versus nonshooter groups. Accuracies for the studied population were 81.8 % (CT), 88.1% (NB), 94.7% (LR), and 95.4% (NN), respectively. The ability to detect both IGSR and OGSR simultaneously provides a selective testing platform for gunshot residues that can provide a powerful field-testing technique and assist with decisions in case management.

Internal dosimetry for TARE therapies by means of GAMOS Monte Carlo simulations.

Three-dimensional internal dosimetry is increasingly used in planning Trans-Arterial Radio-Embolization (TARE) of HepatoCellular Carcinoma (HCC). Among the existing calculation approaches, Monte Carlo (MC) simulation is the gold standard. Aim of this work was to carry out a retrospective study of clinical cases of TARE to compare the performances of different computation approaches. We developed a procedure exploiting GAMOS (GEANT4-based Architecture for Medicine-Oriented Simulations) MC. Three dimensional absorbed dose maps, dose profiles and Dose Volume Histograms (DVHs) were produced for liver through MC simulations and convolution method implemented in STRATOS software. We compared the average absorbed doses with results of Medical International Radiation Dose (MIRD) approach. For most patients, a reasonable agreement was found, with relative differences in mean doses within (-20.2%,+15.6%) for MIRD vs. MC and (-12.1%, +7.6%) for STRATOS vs. MC. Discrepancies can mainly be related to the gamma-rays contribution, more precisely taken into account in MC. For one patient we evaluated through MC simulation a lung dose of about 2 Gy coming from pulmonary shunt (96%) and from irradiation from liver (4%), with values up to 4.5 Gy near liver-lung interface. 3D dosimetry for TARE treatments can be satisfactorily carried out with convolution methods as long as VOIs of regular shape are considered. MC simulations are more appropriate for VOIs where the contribution from gamma-rays has to be carefully taken into account. The absorbed dose distribution in presence of relevant tissue inhomogeneities can be assessed accurately by means of MC simulations only.

CPU time optimization and precise adjustment of the Geant4 physics parameters for a VARIAN 2100 C/D gamma radiotherapy linear accelerator simulation using GAMOS.

We have verified the GAMOS/Geant4 simulation model of a 6 MV VARIAN Clinac 2100 C/D linear accelerator by the procedure of adjusting the initial beam parameters to fit the percentage depth dose and cross-profile dose experimental data at different depths in a water phantom. Thanks to the use of a wide range of field sizes, from 2 × 2 cm2 to 40 × 40 cm2, a small phantom voxel size and high statistics, fine precision in the determination of the beam parameters has been achieved. This precision has allowed us to make a thorough study of the different physics models and parameters that Geant4 offers. The three Geant4 electromagnetic physics sets of models, i.e. Standard, Livermore and Penelope, have been compared to the experiment, testing the four different models of angular bremsstrahlung distributions as well as the three available multiple-scattering models, and optimizing the most relevant Geant4 electromagnetic physics parameters. Before the fitting, a comprehensive CPU time optimization has been done, using several of the Geant4 efficiency improvement techniques plus a few more developed in GAMOS.

Calculation by GAMOS/Geant4 simulation of cellular energy distributions from alpha and lithium-7 particles created by BNCT.

Monte Carlo (MC) has demonstrated to be a suitable technique to evaluate the microdosimetric parameters at the cellular level for Boron Neutron Capture Therapy (BNCT). The objectives of the current study are first to validate GAMOS MC codes with different Geant4 physics models for the range calculations of alpha particles. Once the proper physics is selected, the second objective is to determine the distributions of deposited energy in cellular medium originated by alpha and lithium-7 particles induced by 10B(n,α)7Li.

A new and simpler approach for the solution of the electrostatic potential differential equation. Enhanced solution for planar, cylindrical and annular geometries.

The motivation of the study performed in this project is focused on deriving a more effective, accurate, and mathematically friendly solution for the prediction of the electrostatic potential, commonly used on electrokinetic research and its related applications. In this contribution, based on the Debye-Hückel approximation, a new solution strategy for the differential equations of the electrostatic potential is proposed. In fact, a simple predictor-corrector calculation is developed to achieve more accurate predictions of electrostatic potential profiles. Furthermore, in this study the authors introduce the correction function f(AO) to the inverse Debye length, lambda. The f(AO) function improves the Debye-Hückel approximation and it is a recursive function of the electrical potential. Once the inverse Debye length, lambda, has been corrected by the f(AO) function and introduced in the simplified solution of the Poisson-Boltzmann equation (i.e., the linear approximation, due to Debye and Hückel), the electrostatic potential outcome little differs from the numerical solution of the complete (nonlinear) differential equation. This new approach embraces different geometries of interest, such as planar, cylindrical, and annular, with excellent results in all the cases and for a wide range of electrostatic potential values. This new predicting semi-analytical technique can be a useful tool on electrical field applications such as the separation of a mixture of macromolecules and the removal of contaminants in soil cleaning processes. Illustrative results are presented for the geometries identified above.

PRINCE-1: safety and efficacy of atazanavir powder and ritonavir liquid in HIV-1-infected antiretroviral-naïve and -experienced infants and children aged ≥3 months to <6 years.

INTRODUCTION: PRINCE-1 is an ongoing prospective, international, multicentre, nonrandomized, two-stage clinical trial assessing safety and efficacy of once-daily atazanavir (ATV) powder boosted with ritonavir (RTV) liquid plus optimized dual nucleoside reverse-transcriptase inhibitor (NRTI) background therapy in antiretroviral (ARV)-naïve and -experienced children with HIV-1 infection aged ≥3 months to <6 years. METHODS: Children with HIV-1 infection without prior ATV exposure and with a screening HIV-1 RNA ≥1000 copies/mL were enrolled. The dosing of ATV powder, boosted with 80 mg RTV liquid, was based on three baseline weight bands (5 to <10 kg=150 mg, 10 to <15 kg=200 mg and 15 to <25 kg=250 mg). RESULTS: Of the 56 treated patients, 46 completed 48 weeks of therapy, 67.9% were from Africa and 60.7% were ART-naïve. Median ages at baseline were 6, 35 and 55 months, and proportions with HIV-1 RNA >100,000 were 85.7, 52.6 and 25% in the three baseline weight bands, respectively. No unexpected safety events occurred and no deaths were reported. Over 48 weeks, upper respiratory tract infections, diarrhoea, vomiting and Grade 3 to 4 hyperbilirubinaemia occurred in 35.7, 35.7, 28.6, and 9.4% of patients, respectively; five patients (8.9%) discontinued due to adverse events (AEs); and 11 patients (19.6%) experienced serious adverse events. At Week 48, using a modified intent-to-treat analysis (two patients were excluded because they switched to ATV capsules before Week 48), 61.1 and 74.1% of patients overall had an HIV-1 RNA level <50 copies/mL and <400 copies/mL, respectively. Virologic suppression rates increased across the lowest to highest baseline weight bands (47.6, 68.4 and 71.4% had HIV-1 RNA <50 copies/mL, and 66.7, 73.7 and 85.7% had HIV-RNA <400 copies/mL, respectively) but did not differ meaningfully between ARV-naïve and -experienced patients. Overall, the median change from baseline in CD4 cell count was +363 cells/mm(3), and the median change from baseline in CD4 percent was +7.5%. CONCLUSIONS: ATV powder boosted with RTV liquid once daily plus optimized dual NRTI background therapy was effective and well tolerated in this ART-naïve or -experienced paediatric population aged ≥3 months to <6 years. No unexpected safety findings compared with those from previous ATV paediatric and adult studies were identified.

Cumplimiento del Protocolo de Lavado de Manos por profesionales de enfermería en un servicio de salud de la ciudad de Encarnación, marzo-julio del 2019 / Compliance with the handwashing protocol by nursing professionals in a health service of the city of Encarnacion, March-July 2019

El cumplimiento del protocolo de lavado de manos evita las infecciones nosocomiales, mientras que el incumplimiento ocasiona consecuencias como el aumento de la morbimortalidad, la estancia hospitalaria, así como gastos adicionales al sistema sanitario y al usuario. Esto se puede prevenir con el lavado de manos que surgió como teoría desde la antigüedad. El trabajo de investigación fue de tipo observacional descriptivo con enfoque cuantitativo y fue realizado en 24 enfermeros de un servicio de salud de la ciudad de Encarnación con el objetivo de evaluar el cumplimiento del protocolo del lavado de manos establecido en el Manual de Prevención y Control de Infecciones asociado a la Atención de la Salud del año 2017 del Ministerio de Salud Pública y Bienestar Social. Los resultados evidenciaron un 54% de incumplimiento en la técnica de lavado de manos, un 44% de incumplimiento parcial y solamente un 2% de cumplimiento. En cuanto a los cinco momentos del lavado de manos, el 85% no cumplió con todos los momentos y un 70% no ha recibido capacitación referente al lavado de manos en los últimos 2 años. Se evidenció un alto porcentaje de incumplimiento del protocolo de lavado de manos, lo que representa un riesgo para la salud que podría subsanarse con la realización de cursos de capacitaciones o retroalimentación a los profesionales de enfermería

Compliance of handwashing protocol avoid nosocomial infections, while non-compliance causes consequences such as increased morbidity and mortality, hospital stay, additional cost to the health system and the patient. This can be prevented with handwashing which emerged as a theory in ancient times. This study was descriptive observational with quantitative approach and was carried out in 24 nurses at a health service in the city of Encarnacion in order to evaluate the compliance of handwashing protocol, established in the Infection Prevention and Control Manual associated to Health Care of 2017 of the Ministry of Health Care and Social Welfare. The results showed 54% of non-compliance in the handwashing technique, 44% of partial non-compliance and just 2% of compliance. In relation to the five moments of handwashing technique, 85% did not follow all the steps and 70% did not receive training regarding to the hand washing technique in the last 2 years. A high percentage of non-compliance with the hand washing technique protocol was evidenced, which represents a health risk, which can be corrected with training or feedback workshops for nursing professionals

Simulation of the expected performance of a seamless scanner for brain PET based on highly pixelated CdTe detectors.

The aim of this work is the evaluation of the design for a nonconventional PET scanner, the voxel imaging PET (VIP), based on pixelated room-temperature CdTe detectors yielding a true 3-D impact point with a density of 450 channels/cm(3), for a total 6 336 000 channels in a seamless ring shaped volume. The system is simulated and evaluated following the prescriptions of the NEMA NU 2-2001 and the NEMA NU 4-2008 standards. Results show that the excellent energy resolution of the CdTe detectors (1.6% for 511 keV photons), together with the small voxel pitch (1 × 1 × 2 mm(3)), and the crack-free ring geometry, give the design the potential to overcome the current limitations of PET scanners and to approach the intrinsic image resolution limits set by physics. The VIP is expected to reach a competitive sensitivity and a superior signal purity with respect to values commonly quoted for state-of-the-art scintillating crystal PETs. The system can provide 14 cps/kBq with a scatter fraction of 3.95% and 21 cps/kBq with a scatter fraction of 0.73% according to NEMA NU 2-2001 and NEMA NU 4-2008, respectively. The calculated NEC curve has a peak value of 122 kcps at 5.3 kBq/mL for NEMA NU 2-2001 and 908 kcps at 1.6 MBq/mL for NEMA NU 4-2008. The proposed scanner can achieve an image resolution of ~ 1 mm full-width at half-maximum in all directions. The virtually noise-free data sample leads to direct positive impact on the quality of the reconstructed images. As a consequence, high-quality high-resolution images can be obtained with significantly lower number of events compared to conventional scanners. Overall, simulation results suggest the VIP scanner can be operated either at normal dose for fast scanning and high patient throughput, or at low dose to decrease the patient radioactivity exposure. The design evaluation presented in this work is driving the development and the optimization of a fully operative prototype to prove the feasibility of the VIP concept.

Production of [11C]CO2 with gas target at low proton energies.

Nowadays the demand and the installation of self-shielded low-energy cyclotrons is growing, allowing the use of (11)C in many more centers. The aim of this study was the design of a new target and the evaluation of the production of (11)C as [(11)C]CO2 at low proton energies. The target was coupled to an IBA Cyclone-18/9 and the energy was decreased to 4-16 MeV. The newly designed target allowed the production of [(11)C]CO2 at different proton energies, and the results suggest that the cyclotron energy of Cyclone-18/9 is slightly higher than the nominal 18 MeV.

A GAMOS plug-in for GEANT4 based Monte Carlo simulation of radiation-induced light transport in biological media.

We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Cerenkov effect (light emission from charged particle's traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequent optical photon transport, a dynamic coupled process that is not well-described by any current MC framework. The results of validation simulations show excellent agreement with currently employed biomedical optics MC codes, [i.e., Monte Carlo for Multi-Layered media (MCML), Mesh-based Monte Carlo (MMC), and diffusion theory], and examples relevant to recent studies into detection of Cerenkov light from an external radiation beam or radionuclide are presented. While the work presented within this paper focuses on radiation-induced light transport, the core features and robust flexibility of the plug-in modified package make it also extensible to more conventional biomedical optics simulations. The plug-in, user guide, example files, as well as the necessary files to reproduce the validation simulations described within this paper are available online at http://www.dartmouth.edu/optmed/research-projects/monte-carlo-software.

Effect of capillary geometry on predicting electroosmotic volumetric flowrates in porous or fibrous media.

Electrokinetic-based methods are used in a variety of applications including drug delivery and separation of biomolecules, among others. Many of these applications feature a fibrous or a porous medium that can be modeled by using capillary bundle models to predict the behavior of the electroosmotic flow within the particular system. The role of geometry in predicting volumetric flowrates in porous media is investigated by modeling the electroosmotic flow in idealized capillaries of rectangular, cylindrical, and annular geometries. This is achieved by the coupling of electrostatics and continuum hydrodynamics to obtain analytical expressions that govern the electrokinetically - driven volumetric flow within these idealized capillary geometries. A previous study developed a model to compare the cylindrical and annular capillary geometries by utilizing two methods that compare the areas of the two geometries. The methods used in this previous work will also be used in the present contribution to compare the volumetric flowrates in the cylindrical and annular capillaries with a rectangular capillary. Illustrative results will be presented to aid in the understanding of the influence of the various geometrical and electrostatic parameters that arise from the analysis of these volumetric flowrates. It was found that the electroosmotic volumetric flowrates are significantly affected by the capillary geometry.

[Septic arthritis: practical diagnosis and new treatments]. / Artritis séptica. Rentabilidad diagnóstica y nuevos tratamientos.

Septic arthritis remains a major challenge to physicians because the increasing frequency of certain microorganisms to become in antibiotic-resistant and persistent difficulties regarding both early diagnostics and proper treatment of subjects with joint infections. This paper will review current diagnostics test and their contribution to the rapid evaluation of joint infection. Importantly, updated therapeutic suggestions will be presented which, when appropriately applied, should diminish the risks of sequelae following infectious arthritis.

Optimal separation times for electrical field flow fractionation with Couette flows.

The prediction of optimal times of separation as a function of the applied electrical field and cation valence have been studied for the case of field flow fractionation [Martin M., Giddings J. C., J. Phys. Chem. 1981, 85, 727] with charged solutes. These predictions can be very useful to a priori design or identify optimal operating conditions for a Couette-based device for field flow fractionation when the orthogonal field is an electrical field. Mathematically friendly relationships are obtained by applying the method of spatial averaging to the solute species continuity equation; this is accomplished after the role of the capillary geometrical dimensions on the applied electrical field equations has been assessed [Oyanader M. A., Arce P., Electrophoresis 2005; 26, 2857]. Moreover, explicit analytical expressions are derived for the effective parameters, i.e. diffusivity and convective velocity as functions of the applied (orthogonal) electrical field. These effective transport parameters are used to study the effect of the cation valence of the solutes and of the magnitude of the applied orthogonal electrical field on the values of the optimal time of separation. These parameters play a significant role in controlling the optimal separation time, leading to a family of minimum values, for particular magnitudes of the applied orthogonal electrical field.

Role of geometrical dimensions in electrophoresis applications with orthogonal fields.

The role of geometrical dimensions in electrophoresis applications with axial and orthogonal (secondary) electric fields is investigated using a rectangular capillary channel. In particular, the role of the applied orthogonal electrical field in controlling key parameters involved in the effective diffusivity and effective (axial) velocity of the solute is identified. Such mathematically friendly relationships are obtained by applying the method of spatial averaging to the solute species continuity equation; this is accomplished after the role of the capillary geometrical dimensions on the applied electrical field equations has been studied. Moreover, explicit analytical expressions are derived for the effective parameters, i.e., diffusivity and convective velocity as functions of the applied (orthogonal) electric field. Previous attempts (see Sauer et al., 1995) have only led to equations for these parameters that require numerical solution and, therefore, limited the use of such results to practical applications. These may include, for example, the design of separation processes as well as environmental applications such as soil reclamation and wastewater treatment. An illustration of how a secondary electrical field can aid in reducing the optimal separation time is included.

Design criteria for soil cleaning operations in electrokinetic remediation: hydrodynamic aspects in a cylindrical geometry.

The applications of electrokinetics embrace a large family of important industrial, pharmaceutical, biomedical, and environmental applications. Processes such as separation, drug delivery, soil remediation, and others constitute alist of applications where electrical fields are used to induce the movement of solute species. Different transport driving forces participate in the motion of the solute. In the particular case of soil remediation, the electromechanisms may compete with buoyancy and advection, promoting distinct flow regimes. As a rule of thumb, some of the earlier applications of electrokinetic phenomena, mainly in the area of electrophoresis, neglected this competition, and therefore the hydrodynamics of the systems was considered simpler. The nature of the process in soil, a porous media, calls for a different approach and is in need of further analysis of the complete map of collaborating driving forces. The identification and analysis of the characteristic flow regimes may lead to important guidelines for improving the separation, avoiding the mixing, and more efficient cleaning in a given application. In this contribution, using a cylindrical capillary model, the basic aspects of the behavior of the system are captured. A differential model is formulated using simplifying assumptions, maintaining the mathematical aspects to a minimum level, and a solution is presented for the different fields, i.e., the temperature and the velocity. Based on the selection of values of the parameter space, several limiting cases and flow regimes are presented and discussed. Implications for the design of devices and cleaning strategies are also included. Needs for further research are identified. The main idea behind the study is to obtain a qualitative and semiquantitative description of the different flow regimes inside the channel. This information is useful to identify further aspects of the investigation and delineate a systematic approach for a more rigorous description. More specifically, the authors believe that the results obtained in this study are useful to promote a deeper understanding of the behavior of the system and to have a better idea about the experimental effort needed for validation of the different trends.