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1.
J Environ Manage ; 366: 121863, 2024 Jul 20.
Article in English | MEDLINE | ID: mdl-39033618

ABSTRACT

This study focuses on developing a cost-effective Fe2O3 catalyst from oilfield iron waste to create a floating heterogeneous photo-Fenton system with anatase/rutile(A/R) TiO2 heterophase photocatalyst (cork-Fe2O3@A1-xRx-TiO2) for treating textile pollution in sunlight. Through controlling sol-gel (SG) microwave heating technique, the A/R ratio of A1-xRx-TiO2 crystal is tuned (A/R ratio = 1.13 and Eg = 3.02 eV) to improve adsorption-photocatalytic removal of anionic/cationic dyes with an apparent kinetic rate (kapp) of 0.0074 min-1 under UV-visible irradiation. The developed cork-Fe2O3@A53.1R46.8-TiO2 floated system also outperforms the classical photo-Fenton with Fe/H2O2 benchmark, showing a 2-fold enhancement in textile dye degradation (kapp = 0.216 min-1 and space-time yield (SY) of 1.7*10-4 mol/E.g at pH 5.65) with high stability over four reuse cycles. The formation of Fe2O3@A53.1R46.8-TiO2 Type-II heterojunction is confirmed by optical and electrochemical analyses, allowing the acceleration of direct electron transfer mechanism and oxidative degradation of dyes during photo-Fenton reaction. As a case study, the cork-Fe2O3@A53.1R46.8-TiO2 system demonstrates a high capability for efficient mineralization of textile pollution in a real effluent, achieving 82 ± 2% reduction in the total organic contents at an operational cost of 2.61 $/kg.m3 in sunlight. Thus, this research addresses challenges in conventional Fenton chemistry, iron waste recycling, and catalyst retention, offering new insights for sustainable treatment of textile effluents and environmental protection.

2.
Phys Rev Lett ; 132(16): 164001, 2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38701479

ABSTRACT

We study fluctuations of the local energy cascade rate Φ_{ℓ} in turbulent flows at scales (ℓ) in the inertial range. According to the Kolmogorov refined similarity hypothesis (KRSH), relevant statistical properties of Φ_{ℓ} should depend on ε_{ℓ}, the viscous dissipation rate locally averaged over a sphere of size ℓ, rather than on the global average dissipation. However, the validity of KRSH applied to Φ_{ℓ} has not yet been tested from data. Conditional averages such as ⟨Φ_{ℓ}|ε_{ℓ}⟩ as well as of higher-order moments are measured from direct numerical simulations data, and results clearly adhere to the predictions from KRSH. Remarkably, the same is true when considering forward (Φ_{ℓ}>0) and inverse (Φ_{ℓ}<0) cascade events separately. Measured ratios of forward and inverse cascade probability densities conditioned on ε_{ℓ} also confirm the applicability of the KRSH to analysis of the fluctuation relation from nonequilibrium thermodynamics.

3.
Metab Syndr Relat Disord ; 22(4): 281-286, 2024 May.
Article in English | MEDLINE | ID: mdl-38502809

ABSTRACT

Background: The risk and metabolic effects of obesity are determined by the distribution of fat throughout the body. It has been proposed that the distribution of abdominal fat is more closely related to the metabolic risks of obesity. High prevalence of overweight and obesity has thereby contributed to an increased uptake of surgical subcutaneous fat removal (SSFR) procedures. The goal of this study was to determine whether bioelectrical impedance analysis (Tanita system) can be used to detect the removal of excess abdominal subcutaneous fat tissue during SSFR when studying the metabolic effects of such procedures. Methods: Study population comprised patients who received body contouring procedures at the Hamad General Hospital's plastic surgery department between November 2020 and December 2022. To evaluate the factors of interest, subjects were prospectively followed up at two time points: within 1 week before the surgery and within 1-2 weeks thereafter. The following factors were measured: body weight, body fat percentage, body fat mass, body mass index (BMI), fat-free mass, estimated muscle mass, total body water, visceral fat score, and basal metabolic rate. Results: In total, 22 patients were included in the study. The two visits' medians for height, weight, BMI, fat percent (fat%), fat mass, visceral fat rating, and Doi's weighted average glucose (dwAG) were compared. Only in the case of Tanita fat% and fat mass, were the preoperative and postoperative medians significantly different. Furthermore, there was no association between these Tanita measures and dwAG or homeostatic model assessment (HOMA; insulin resistance [IR]) changes (before and after surgery). Tanita measures overestimated fat loss, as seen by the mountain plot and Bland-Altman plot agreement methods. Conclusions: Our findings indicated that the only two Tanita measures exhibited meaningful early associations with the amount of tissue excised which were fat mass and fat% differences. Although dwAG and HOMA-IR are not impacted immediately postsurgery, a trend was seen that suggested improvements in those parameters, even though the changes are not clinically significant.


Subject(s)
Electric Impedance , Subcutaneous Fat , Humans , Female , Male , Middle Aged , Adult , Body Contouring/adverse effects , Prospective Studies , Body Mass Index , Body Composition , Obesity/surgery , Obesity/diagnosis
4.
Open Med (Wars) ; 18(1): 20230817, 2023.
Article in English | MEDLINE | ID: mdl-37808165

ABSTRACT

Global brachial plexus injury (GBPI) mainly affects adults and causes severe life-changing consequences that lead to the deterioration of patients' quality of life. Several surgical approaches have been described and reported in the literature to improve patients' functional ability. A literature review is done on PubMed/MEDLINE and Embase using specific keywords to retrieve relevant articles assessing different surgical approaches for GBPI management. Inclusion and exclusion criteria were applied, and eligible articles were included in the review. The literature survey revealed that various surgical options had been used to manage GBPI patients. In this concise review, we discuss and compare the different surgical approaches related to GBPI and its outcome in terms of restoring elbow flexion and extension, shoulder abduction, and wrist and hand function. The primary surgical intervention relies mainly on transferring single or multiple nerves with/without nerve grafts to restore the function of the targeted muscle. Different techniques using a variety of nerve donors and recipients are compared to assess the functional outcomes of each option. Moreover, further options are addressed for delayed GBPI injuries or failed nerve transfer procedures, as in free functional muscle transfer techniques. In addition, information about brachial plexus injury cases faced in our center is presented along with our center's approach to diagnosing and managing partial and GBPI cases.

5.
Plast Reconstr Surg Glob Open ; 10(4): e4240, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35506022

ABSTRACT

Upper limb muscle anomalies and their clinical implications have been described frequently in the literature reviews. In this article, we are presenting a case of aberrant forearm muscle that had not been described before, and could be considered as a palmaris longus muscle variation. A 24-year-old man presented to the emergency department, Hamad General Hospital, Doha, Qatar, with right forearm laceration with multiple cut structures for which he was admitted for exploration and repair. Intraoperatively, flexor digitorum superficialis of the third, fourth, and fifth digits, flexor carpi radialis, and palmaris longus were injured' and all of them were repaired. We noticed an aberrant muscle-which was also injured-that originated from the distal third of the radius on its medial aspect to insert into the palmar fascia; pulling this muscle's tendon resulted in tightening of palmar fascia' same as the palmaris longus. Along with the importance of deep knowledge of typical human anatomy, hand surgeons must be aware that an aberration from normal anatomy might be anticipated, to provide the best care to our patients.

6.
Plast Reconstr Surg Glob Open ; 9(2): e3434, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33680678

ABSTRACT

Distal thumb injuries are common in high construction load regions, and it is a challenging task for the plastic surgeon to find the optimum choice that preserves thumb length and provides a sensory substitute to the lost tissue. Introducing first dorsal metacarpal artery flap has solved the dilemma. One drawback is that the flap is susceptible to distal necrosis, which can happen because of tight tunneling or insufficient venous drainage. We combined Foucher and Holevich characteristics to design a flap that promises to solve the problem. METHODS: This is a case series that includes 9 patients where we describe a technique that has the potential to enhance the survival of the first dorsal metacarpal artery (FDMA) flap and decreases the rate of distal necrosis via addition of a 5-mm skin bridge to the pedicle and by avoiding tunneling. Distal necrosis of the patients in this study patients was compared with that in a control of 10 patients in whom we did the conventional FDMA flap. Patients were followed for 6 weeks to trace early postoperative complications (infection, dehiscence, and necrosis) and the establishment of protective sensation (pain and temperature). RESULTS: None of our patients had distal necrosis, infection, or dehiscence, and all had protective sensation in the flap. In comparison, 4 patients in the control group developed distal necrosis. CONCLUSION: FDMA is one of the best choices when it comes to distal thumb reconstruction, but it has the disadvantage of distal necrosis, which might be avoided when using the technique mentioned in this study.

7.
J Hazard Mater ; 360: 250-256, 2018 10 15.
Article in English | MEDLINE | ID: mdl-30121355

ABSTRACT

Ternary nanocomposite Ag2CO3@Fe2O3/TiO2-NT (AFT), compared with binary Fe2O3/TiO2-NT (FTNT) and TiO2 nanotube (TNT), showed remarkably enhanced performance for catalytic photodegradation of phenol compounds in the presence of solar irradiation. AFT nanocomposite performed high degradation efficiency (96.5%) and high degree of sustainability. The unique catalytic properties of the nanocomposite such as synergetic light absorption, efficient charge separation-transfer and resistance toward photocorrosion suggested three possible alternative mechanisms for transferring photogenerated electrons. Ag2CO3@Fe2O3/TiO2-NT nanocomposite may have a potential application for the industrial treatment of wastewater containing toxic organic contamination.

8.
J Chem Phys ; 142(7): 074110, 2015 Feb 21.
Article in English | MEDLINE | ID: mdl-25702005

ABSTRACT

A method which controls momentum evolution in a sub-region within a molecular dynamics simulation is derived from Gauss's principle of least constraint. The technique for localization is founded on the equations by Irving and Kirkwood [J. Chem. Phys. 18, 817 (1950)] expressed in a weak form according to the control volume (CV) procedure derived by Smith et al. [Phys. Rev. E. 85, 056705 (2012)]. A term for the advection of molecules appears in the derived constraint and is shown to be essential in order to exactly control the time evolution of momentum in the subvolume. The numerical procedure converges the total momentum in the CV to the target value to within machine precision in an iterative manner. The localized momentum constraint can prescribe essentially arbitrary flow fields in non-equilibrium molecular dynamics simulations. The methodology also forms a rigorous mathematical framework for introducing coupling constraints at the boundary between continuum and discrete systems. This functionality is demonstrated with a boundary-driven flow test case.

9.
J Chem Phys ; 140(5): 054506, 2014 Feb 07.
Article in English | MEDLINE | ID: mdl-24511951

ABSTRACT

Various formulas for the local pressure tensor based on a spherical subvolume of radius, R, are considered. An extension of the Method of Planes (MOP) formula of Todd et al. [Phys. Rev. E 52, 1627 (1995)] for a spherical geometry is derived using the recently proposed Control Volume formulation [E. R. Smith, D. M. Heyes, D. Dini, and T. A. Zaki, Phys. Rev. E 85, 056705 (2012)]. The MOP formula for the purely radial component of the pressure tensor is shown to be mathematically identical to the Radial Irving-Kirkwood formula. Novel offdiagonal elements which are important for momentum conservation emerge naturally from this treatment. The local pressure tensor formulas for a plane are shown to be the large radius limits of those for spherical surfaces. The radial-dependence of the pressure tensor computed by Molecular Dynamics simulation is reported for virtual spheres in a model bulk liquid where the sphere is positioned randomly or whose center is also that of a molecule in the liquid. The probability distributions of angles relating to pairs of atoms which cross the surface of the sphere, and the center of the sphere, are presented as a function of R. The variance in the shear stress calculated from the spherical Volume Averaging method is shown to converge slowly to the limiting values with increasing radius, and to be a strong function of the number of molecules in the simulation cell.

10.
Phys Rev E Stat Nonlin Soft Matter Phys ; 85(5 Pt 2): 056705, 2012 May.
Article in English | MEDLINE | ID: mdl-23004901

ABSTRACT

A molecular dynamics (MD) parallel to the control volume (CV) formulation of fluid mechanics is developed by integrating the formulas of Irving and Kirkwood [J. Chem. Phys. 18, 817 (1950)] over a finite cubic volume of molecular dimensions. The Lagrangian molecular system is expressed in terms of an Eulerian CV, which yields an equivalent to Reynolds' transport theorem for the discrete system. This approach casts the dynamics of the molecular system into a form that can be readily compared to the continuum equations. The MD equations of motion are reinterpreted in terms of a Lagrangian-to-control-volume (LCV) conversion function ϑ(i) for each molecule i. The LCV function and its spatial derivatives are used to express fluxes and relevant forces across the control surfaces. The relationship between the local pressures computed using the volume average [Lutsko, J. Appl. Phys. 64, 1152 (1988)] techniques and the method of planes [Todd et al., Phys. Rev. E 52, 1627 (1995)] emerges naturally from the treatment. Numerical experiments using the MD CV method are reported for equilibrium and nonequilibrium (start-up Couette flow) model liquids, which demonstrate the advantages of the formulation. The CV formulation of the MD is shown to be exactly conservative and is, therefore, ideally suited to obtain macroscopic properties from a discrete system.

11.
J Chem Phys ; 136(13): 134705, 2012 Apr 07.
Article in English | MEDLINE | ID: mdl-22482578

ABSTRACT

Non-equilibrium molecular dynamics simulations of boundary-driven sheared Lennard-Jones liquids at variable pressure up to 5 GPa (for argon) reveal a rich out-of-equilibrium phase behavior with a strong degree of shear localization. At the lowest apparent shear rate considered (wall speed ~1 m s(-1)) the confined region is an homogeneously sheared solid (S) with no slip at the walls. This transforms at higher shear rates to a non-flowing plug with slip at the walls, referred to as the plug slip (PS) state. At higher shear rate a central localized (CL) state formed in which the shear gradient was localized in the center of the film, with the rest of the confined sample in a crystalline state commensurate with the wall lattice. The central zone liquidlike region increased in width with shear rate. A continuous rounded temperature profile across the whole system reflects strong dynamical coupling between the wall and confined region. The temperature rise in the confined film is consistent with the Brinkman number. The transition from the PS to CL states typically occurred at a wall speed near where the shear stress approached a critical value of ~3% of the shear modulus, and also near the peak in the traction coefficient, µ. The peak traction coefficient values computed, ~0.12-0.14 at 1000 MPa agree with those found for traction fluids and occur when the confined liquid is in the PS and CL states. At low wall speeds slip can occur at one wall and stick at the other. Poorly wetting liquids manifest long-lived asymmetries in the confined liquid properties across the system, and a shift in solid-liquid phase co-existence to higher shear rates. A non-equilibrium phase diagram based on these results is proposed. The good agreement of the tribological response of the Lennard-Jones fluid with that of more complicated molecular systems suggests that a corresponding states scaling of the tribological behavior could apply.

12.
J Chem Phys ; 135(2): 024512, 2011 Jul 14.
Article in English | MEDLINE | ID: mdl-21766962

ABSTRACT

It is shown analytically that the method of planes (MOP) [Todd, Evans, and Daivis, Phys. Rev. E 52, 1627 (1995)] and volume averaging (VA) [Cormier, Rickman, and Delph, J. Appl. Phys. 89, 99 (2001)] formulas for the local pressure tensor, P(α, y)(y), where α ≡ x, y, or z, are mathematically identical. In the case of VA, the sampling volume is taken to be an infinitely thin parallelepiped, with an infinite lateral extent. This limit is shown to yield the MOP expression. The treatment is extended to include the condition of mechanical equilibrium resulting from an imposed force field. This analytical development is followed by numerical simulations. The equivalence of these two methods is demonstrated in the context of non-equilibrium molecular dynamics (NEMD) simulations of boundary-driven shear flow. A wall of tethered atoms is constrained to impose a normal load and a velocity profile on the entrained central layer. The VA formula can be used to compute all components of P(αß)(y), which offers an advantage in calculating, for example, P(xx)(y) for nano-scale pressure-driven flows in the x-direction, where deviations from the classical Poiseuille flow solution can occur.

13.
J Colloid Interface Sci ; 284(2): 606-13, 2005 Apr 15.
Article in English | MEDLINE | ID: mdl-15780300

ABSTRACT

The aim of this work is to study catalytic ethanol dehydration using different prepared catalysts, which include Fe(2)O(3), Mn(2)O(3), and calcined physical mixtures of both ferric and manganese oxides with alumina and/or silica gel. The physicochemical properties of these catalysts were investigated via X-ray powder diffraction (XRD), acidity measurement, and nitrogen adsorption-desorption at -196 degrees C. The catalytic activities of such catalysts were tested through conversion of ethanol at 200-500 degrees C using a catalytic flow system operated under atmospheric pressure. The results obtained indicated that the dehydration reaction on the catalyst relies on surface acidity, whereas the ethylene production selectivity depends on the catalyst chemical constituents.

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