An experimental investigation of the convective heat transfer augmentation in U-bend double pipe heat exchanger using water-MgO-Cmc fluid.

One of the major problems of using nanofluids in heat exchange applications is the forming and deposition of nanoparticles on the inner surface of the heat exchanger. In this paper, Water-Cmc fluid is used as a surfactant for nanoparticles to prevent deposition and congregation. The pressure drops and heat transfer in U-bend double pipe heat exchanger based on water-MgO-Cmc fluid, are examined. Nanoparticles of Magnesium Oxide (MgO) and Carboxymethyl Cellulose (Cmc) are used with pure water as a base fluid. The experimental rig and procedures are designed to facilitate various operational conditions such as flow rate, volume concentration of MgO particles and weight concentration of Cmc particles. Furthermore, convective heat transfer coefficient, heat exchanger effectiveness, pressure drop, friction factor, under different conditions, are measured. The results demonstrate convective heat transfer coefficient of U-bend double pipe heat exchangers is enhanced by 35% for 1 MgO vol.% and 0.2 Cmc wt.% compared to base fluid (Water-Cmc). It is concluded that pressure drops are directly proportion to the increase of MgO nanoparticles at same Cmc concentration by 23% at 0.2 wt.%. Whilst, friction factor of the system is inversely proportion to the increase of volumetric flow rate of water-MgO-Cmc fluid. An increase in MgO nanoparticle concentration increases the friction factor, hence maximum friction factor enhancement by 38% for MgO concentration of 1 vol.%. The effectiveness of heat exchanger is slightly increased by 8% with increase of MgO concentration and flow rate. Finally, thermo-physical characteristics of water-MgO-Cmc fluid at various temperatures, are measured.

Nanoencapsulated phase change material in a trapezoidal prism wall under the magnetic field effect for energy storage purposes.

Recently, Nano-encapsulated phase change materials (NEPCM) have attracted the attention of researchers due to their promising application in thermal management. This research investigates magnetohydrodynamic mixed convection of NEPCM contained within a lid-driven trapezoidal prism enclosure containing a hot-centered elliptical obstacle. The upper cavity wall is moving at a constant velocity; both inclined walls are cold, while the rest of the walls are insulated. The Galerkin Finite Element Method was used to solve the system's governing equations. The influence of Reynolds number (Re 1-500), Hartmann number (Ha = 0-100), NEPCM volumetric fraction φ (0-8%), and elliptical obstacle orientation α (0-3π/4) on thermal fields and flow patterns are introduced and analyzed. The results indicated that the maximum heat transfer rate is observed when the hot elliptic obstacle is oriented at 90°; an increment of 6% in the Nu number is obtained in this orientation compared to other orientations. Reducing Ha from 100 to 0 increased Nu by 14%. The Maximum value of the Bejan number was observed for the case of Ha = 0, α = 90° and φ = 0.08.

The efficacy of adding topical 5-fluorouracil to micro-needling in the treatment of vitiligo: A randomized controlled trial.

BACKGROUND AND AIM: Vitiligo is an autoimmune skin disorder characterized by circumscribed depigmented macules and patches caused by the loss of functional melanocytes. Although there is no definitive treatment for vitiligo, several treatment options have been associated with relative satisfactory outcomes. The purpose of this study was to compare the efficacy of micro-needling in conjunction with topical 5-fluorouracil (5-FU) versus topical tacrolimus ointment in treating vitiligo patches. PATIENTS AND METHODS: This study included nineteen participants, each of whom received both treatments on two randomly selected vitiligo patches of approximately the same size and location. On one patch, a combination of weekly micro-needling and topical application of 5-FU solution was used every other day, while on the other, 0.1% tacrolimus topical ointment was applied twice daily. The G-score was used to compare treatment outcomes after 3 months. RESULTS: The median duration of the disease in our population was 7 years. Six patients (32%) in the micro-needling plus topical 5-FU treated group showed a moderate to excellent response, indicating a significant improvement between both treatments (p-value = 0.019). In contrast, all other patches treated with topical tacrolimus showed poor improvement. Lower extremity and trunk responded more to treatment with micro-needling plus topical 5-FU than upper extremity and acral areas. Moreover, none of those who have had the disease for more than ten years have responded to treatment. Mild erythema, pinpoint bleeding, and irritation were detected only in the micro-needling treated group. CONCLUSION: The current study showed that using micro-needling in conjunction with 5-FU could treat vitiligo patients more efficiently than tacrolimus monotherapy. Despite showing moderate to excellent improvement in patches treated with micro-needling and 5-FU, this well-tolerated office-based modality still requires additional research.

The impacts of shape factor and heat transfer on two-phase flow of nano and hybrid nanofluid in a saturated porous medium.

The focus of this article is to obtain the effect of shape factor of the hybrid nanoparticles on the convective heat and mass transference of two immiscible fluids in an inclined duct by employing the perturbation technique. The hybrid nanoparticle of Carbon Nanotube & Sodium alginate is being used with Silicon oil as the base fluid to study the heat and mass phenomena due to the soret effect, viscous dissipation, Darcy and Thermal diffusion. The physical flow problem is then modelled into a set of differential equations. The system of equations is solved analytically to obtain various graphical and numerical results for analyzing the impact of various material parameters on velocity and thermal field. The heat transfer rate and skin friction analysis for the flow dynamics are also investigated. It is observed that the shape factor enhances the fluid flow and temperature distribution. In specific lamina shape particles have better performance comparatively, significance of the soret number can also be observed.

Comparing the Effects of Pregabalin and Clonidine on Postoperative Pain in Tonsillectomy: A Randomized, Double-Blind, Prospective Clinical Trial.

BACKGROUND: Tonsillectomy is one of the most common surgical procedures. This study compared the effect of Pregabalin and Clonidine on postoperative pain in adult patients undergoing elective tonsillectomy. METHODS: This randomized, double-blind, prospective clinical trial was conducted among 92 patients aged 20 to 50. The clonidine group (C) was given 150 µg of clonidine tablet 90 minutes before surgery, and the pregabalin group (P) was given 300 mg of pregabalin tablet 90 minutes before surgery. The results were analyzed by SPSS 25, and statistical analysis consisted of chisquare, T-test, and χ2 tests, and a p-value less than 0.05 was considered significant. RESULTS: The mean pain score and analgesic consumption scores in the pregabalin group were lower than in the clonidine group. According to the t-test, there was a significant difference between the two groups regarding pain score and analgesic consumption (p <0.05). Hemodynamic variation in both groups had no significant differences (p >0.05). CONCLUSION: The present study showed that pregabalin reduced postoperative pain and analgesic consumption more effectively than clonidine.

Effectiveness of Mindfulness-Based Stress Reduction Therapy on the Quality of Life of Patients with Lung Cancer.

Background: Lung cancer is one of the most common and life-threatening cancers in men around the world. Therefore, it is important to pay particular attention to the psychological status of patients with lung cancer due to their greater vulnerability during treatment. This study aimed to evaluate the effectiveness of mindfulness-based stress reduction therapy on the quality of life of patients with lung cancer. Materials and Methods: This quasi-experimental study, with a pretest-posttest design and a three-month follow-up, was conducted in the summer of 2019. Thirty patients with lung cancer, who were referred to Masih Daneshvari Hospital in Tehran, Iran, were selected through purposive sampling and randomly assigned to experimental (n=15) and control (n=15) groups. In the pretest stage, the Short-Form Health Survey (SF-36) was completed by both groups. The experimental group received mindfulness-based stress reduction therapy for eight sessions, while the control group did not receive any intervention. In the posttest stage, both groups were examined again, and data were analyzed using SPSS version 21 by repeated measures multivariate analysis of variance (MANOVA). Results: The findings showed a significant difference between the experimental and control groups after mindfulness-based stress reduction therapy. In other words, the mean score of quality of life increased in the experimental group as compared to the control group (P<0.001). Conclusion: Based on the results of this study, the effectiveness of mindfulness-based stress reduction therapy in increasing the quality of life of patients with lung cancer was confirmed. Therefore, psychological screening is suggested to improve the quality of life of patients by taking advantage of clinical trials and appropriate intervention models during medical treatment.

Investigation of operation parameters on the removal efficiency of methyl orange pollutant by cellulose/zinc oxide hybrid aerogel.

In this study, Cellulose/Zinc Oxide-x (CA/ZnO-x) hybrid aerogel with various concentrations of Zn2+ ion is synthesized through the hydrothermal method and used for organic pollutant removal. The CA/ZnO-x hybrid aerogel was characterized by XRD, UV-Visible, DRS, FTIR, FESEM, EDS, BET, LC-MS-MS analyses. In the present study, CA/ZnO-x hybrid aerogel as photocatalyst was used to investigate the influence of the photocatalytic degradation of methyl orange (MO) from an aqueous solution under UV irradiation. The morphology of CA/ZnO-x hybrid aerogels exhibited that the ZnO rice grain-like shape were successfully synthesized on the cellulose aerogel matrix. Also, the influence of various factors such as photocatalyst dosage, pH, initial concentration of MO, and irradiation intensity was investigated on the photocatalytic degradation rate of MO. The results revealed that the highest degradation efficiency and mineralization rate of MO were about 99.02% and 51.68%, respectively, after 90 min under UV irradiation using CA/ZnO-0.4 photocatalyst when pH = 3, C0 = 10 ppm, photocatalyst dose = 9 g L-1 under the 300 W UV light irradiation. Furthermore, the synthesized photocatalyst exhibited a considerable firmness and easily separated from an aqueous solution for reuse.

Optimization of fins arrangements for the square light emitting diode (LED) cooling through nanofluid-filled microchannel.

In current paper, a finned micro-channel is designed for the cooling application in Light Emitting Diode (LED), numerically using Galerkin weighted residual Finite Element Method (GFEM). Selected materials for LED-chip is GaN, Die from Si, Die-attach is made by Au-20Sn, substrate is copper and heat sink material is considered to be Al. To make a convection heat transfer for cooling process, Al2O3-water nanofluid is used as the cooling fluid flow through the micro-channel and tried to maximize the heat transfer efficiency by optimized geometry. For this aim, there geometry variables from the microchannel were selected and minimum possible geometry cases (11 cases) were proposed by Central composite design (CCD) and variables were optimized by the Response Surface Method (RSM). As a main result, parameter B, i.e. fin length had the most effect on the Nusselt number and Al2O3 nanoparticles with φ = 0.05 stated greatest heat transfer value. Also, different designs of fins arrangements, caused up to 6.5% increase in the nanofluid temperature which enhanced the LED cooling process.

Application of three dimensional porous aerogels as adsorbent for removal of heavy metal ions from water/wastewater: A review study.

Nowadays, by rapid development of economies and industries, water contamination through the heavy metal ions (toxic, non-toxic and radioactive) is a great concern and an important environmental problem. Currently, numerous techniques such as chemical precipitation, coagulation, ion-exchange, filtration, reverse osmosis, biological treatment and physical adsorption are presented by researchers for removing and recycling heavy metal ions from wastewater. Among these methods, adsorption approach is one of the most efficient techniques for the elimination of heavy metal ions from aqueous solutions. There are a number of low cost absorbent such as agricultural and industrial solid waste such as lingo-cellulosic materials, wheat bran, peanut shell, moss peat, fly ash, bagasse, tree fern, gram husk, nanostructures (such as TiO2, SiO2, SnO2, ZnO, etc.), 3D porous structures (aerogels), etc. which have been developed and tested to efficient removal of heavy metal ions from wastewater. In this study, a critical review of the applications of aerogels in water and sewage purifications is performed. For this reason, different kinds of aerogel namely organic, inorganic and organic-inorganic hybrid aerogels are investigated. It is concluded that the most applicable aerogels used in these studies are graphene-based aerogels due to more porous structure as well as simplification of their modification. Also, in this review paper, for the first time we summarized and highlighted the recent literature information about heavy metal ions and theirs removal methods from aqueous pollutants and wastewater/water, adsorption kinetics, isotherms and thermodynamics models by different type of three dimensional (3D) porous structure. In additional, in this review article, the influence of various parameters such as pH solution, temperature, initial concentration of heavy metal ions, composition, contact time, coexisting ions and adsorbent dosage on the adsorption process of heavy metal ions were investigated.

Can breast ultrasound reduce patient's level of anxiety and pain?

BACKGROUND: Breast pain is one of the most common complaints of women attending a gynecology clinic and general practitioners. This pain can cause anxiety and, consequently, reduce the woman's quality of life. The objective of this study was to assess the severity of pain and anxiety in patients with breast pain and normal examination, before and after breast sonography. MATERIALS AND METHODS: Among the patients with breast pain and normal examination who came for breast sonography in three centers in Shiraz during 2011-2012, 51 patients agreed to cooperate in this project. These patients filled out the questionnaire for evaluation of pain and anxiety before and after breast sonography. RESULTS: Sonography findings indicated that 88% of patients have normal sonography without any finding. The average amounts of pain severity before and after sonography were 3.3 and 2.4, respectively (p < 0.005). The average amounts of anxiety severity in patients before and after sonography were 51.9 and 37.9, respectively (p < 0.005). CONCLUSION: This study shows the severity of pain and anxiety after ultrasonography decreased significantly. It can be concluded that ultrasound findings, which reassure the patients that they do not have specific pathology, can reduce the pain and anxiety by its impact on psychological status of the patient.

Clinicopathological study of lacrimal sac specimens obtained during DCR.

PURPOSE: To determine the histopathologic characteristics of lacrimal sac specimens in adult patients undergoing external dacryocystorhinostomy (DCR) for acquired nasolacrimal duct obstruction. METHODS: A total of 471 lacrimal sac biopsies were obtained from 449 patients undergoing external DCR for symptoms or signs of acquired nasolacrimal duct obstruction and examined histopathologically. RESULTS: A total of 449 subjects including 283 (63%) female and 166 (37%) male subjects with mean age of 50.02 years underwent DCR and histopathologic examination of specimens. Presenting symptoms were epiphora in 411 patients (91%), history of acute dacryocystitis in 17 patients (4%) and obstruction revealed during ophthalmic examinations in 21 patients (5%). Histopathologic findings included: chronic inflammation in 450 patients (95.5%), fibrosis in 18 patients (3.8%), lymphoma in two patients (0.4%) and reactive lymphoid hyperplasia in one patient (0.2%). Lacrimal sac appearance during surgery was grossly abnormal in two cases: one case of lymphoma and one instance of reactive lymphoid hyperplasia. CONCLUSIONS: Chronic inflammation and fibrosis are the most common histopathologic findings in lacrimal sac specimens obtained during DCR. Only two cases of lymphoma (0.4%) were encountered in the series, one of which had a suspicious lacrimal sac appearance during surgery while the other case (0.2% of all specimens) was unsuspected. The rate of malignant etiology for NLD obstruction is low enough to justify lacrimal sac biopsy only in suspicious cases.