149 research outputs found

    Investigation on the Removal of Carbon Dioxide Exhausted from Industrial Units in a Lab-Scale Fluidized Bed Reactor

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    In this study, CO2 removal efficiency from flue gas was investigated in a fluidized bed reactor under semi-dry conditions. A lab-scale fluidized bed reactor, filled with inert glass beads, was used to investigate the effect of operating parameters on the CO2 removal efficiency using calcium hydroxide slurry as the absorbent. The Taguchi design method was used to design the experiments. The maximum inlet concentration of CO2 was 3 vol%. The most important factors were the reaction surface area, inlet gas velocity, inlet CO2 concentration, absorbent solution flow rate, inlet gas temperature and calcium hydroxide slurry concentration. The experimental results indicated that the CO2 removal efficiency increased when increasing the effective surface area of the reaction. Moreover, the removal efficiency increased by decreasing the input gas flow rate and inlet CO2 concentration. By performing experiments under optimum conditions, the maximum obtained CO2 removal efficiency was 79%. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

    Effect of Operating Conditions of the Extraction Process on the Physical Properties of Lubricating Oil

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    Lubricating base oil is commonly extracted from lube-oil cut, a petroleum cut, with the use of an aromatic solvent. Aromatic content of the final product is an important criterion specifying the product quality. The aromatic removal process to produce the lubricating oil should be carried out in a Liquid-Liquid extraction column. In a typical solvent extraction process, solvent to feed ratio, solvent and feed temperatures, agitation rate, and settling time could directly affect the yield of extraction. In the current study, the effect of agitation rate and settling time on the yield of extraction was studied. It was found that a settling time of 2hrs and an agitation rate of 430 RPM to be the optimum parameters of the extraction process

    Revisiting the Figure of Merit of Concentrated Solar Power Receivers

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    The figure of merit (FOM) is a widely used metric to characterize the performance of concentrated solar power (CSP) receivers by comparing the amount of solar thermal energy retained by the receiver to the incident concentrated solar radiation. However, the FOM is a strong function of the concentration factor and receiver temperature, thus direct comparison of FOM values measured under disparate operating conditions is inappropriate. To remedy this problem, the present study proposes a new metric called the receiver effectiveness calculated by normalizing the actual FOM with its theoretical maximum. The receiver effectiveness can be employed for comparing receiver performances regardless of their operating conditions, and can be treated as more-like the second law efficiency of thermodynamics. In addition, a theoretical limit of the CSP plant efficiency is also examined by combining the maximum FOM and the Carnot efficiency for different concentration factors and receiver temperatures. The calculated maximum CSP plant efficiency clearly indicate that optimizing FOM does not always lead to a better CSP plant performance. Along with the FOM, the proposed receiver effectiveness and maximum CSP system efficiency should be considered as complementary metrics to evaluate the performance of the CSP system

    Novel nanomicelle formulation to enhance bioavailability and stability of curcuminoids

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    Objective(s): Curcuminoids, comprising curcumin, demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), are bioactive phytochemicals with numerous pharmacological effects. Oral biological availability of curcuminoids is low due to the low aqueous solubility and rapid metabolism. This study aimed at fabricating a nanomicellar curcuminoid formula with enhanced pharmacokinetic properties. Materials and Methods: Curcuminoids nanomicelles were prepared and characterized regarding particle properties, stability, release profile and pharmacokinetic parameters.Results: Encapsulation efficiency of curcuminoids in nanomicelles were 100%. Particle size analysis demonstrated a mean size of around 10 nm that remained stable for 24 months. Dissolution test showed the complete dissolution of encapsulated curcuminoids from nanomicelles within 20 min while the free curcuminoids were poorly dissolved (approximately 7% after 60 min). The results of long-term (24 months) and accelerated (6 months) stability studies showed no changes in the size and content of nanomicelles. The release studies in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) showed no release of curcuminoids for at least 4 hours. In vivo study in BALB/c mice showed improved pharmacokinetic parameters including maximum plasma concentration (Cmax) and time to reach the maximum concentration (Tmax) with nanomicelles as compared to free curcuminoids and two other commercial products. Tmax for all the three curcuminoid components was observed 30 min following oral administration. AUC of nanomicellar curcuminoids was 59.2 times more than free  curcuminoids. Conclusion: These data indicated that nanomicelles could improve solubility, oral bioavailability and also the stability of curcuminoids. Thus, they merit further investigation for enhancing pharmacological effects of curcuminoids

    Liposome Circulation Time is Prolonged by CD47 Coating.

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    INTRODUCTION: Bio-degradable nano-particles have many applications as drug delivery vehicles because of their good bio-availability, controlled release, low toxicity and potential for encapsulation. However, the most important obstacle to nanoparticulate drug delivery is elimination by macrophages which reduces the residence time of nanoparticles in the blood. To overcome this problem, the surface of the nanoparticle can be passivated by coating with Polyethylene glycol (PEG). However, the use of PEG has its own disadvantages. CD47 receptor acts as a self marker on the surface of many cells and inhibits phagocytosis. This study used a CD47 mimicry peptide as a substitute for PEG to fabricate "stealth" nanoliposome with reduced macrophage clearance. METHODS: Doxorubibin was used as a model drug because of its inherent fluorescence. Doxorubicin-containing liposomes were coated with different percentages of CD47 mimicry peptide (0.5% and 1%). PEGfunctionalized doxorubicin-containing liposomes, were used as a comparator. The liposomal formulations were intravenously injected into mice. Serum was collected at pre-defined time points and tissue samples were taken at 24 hours. Fluorescence was used to determine the concentration doxorubicin in serum, heart, spleen, kidney, liver and lung tissues. RESULTS: Tissue biodistribution and serum kinetic studies indicated that compared with PEG, the use of CD47 mimicry peptide increased the circulation time of doxorubicin in the circulation. Moreover, unwanted accumulation of doxorubicin in the reticuloendothelial tissues (liver and spleen), kidney and heart was significantly decreased by the CD47 mimicry peptide. CONCLUSION: The use of a CD47 mimicry peptide on the surface of nanoliposomes improved the residence time of liposomal doxorubicin in the circulation. The accumulation of drug in non-target tissues was reduced, thereby potentially reducing toxicity

    Application of Glycyrrhiza glabra

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    The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR) as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R) isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants

    Spiritual aspects of living with infertility: synthesis of qualitative studies.

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    AIM: To identify the spiritual aspects of patients experiencing infertility and seek a deeper and broader meaning of the involuntary childlessness experience. BACKGROUND: Infertility can be the cause for a spiritual crisis among some couples. Those who endure this involuntary childlessness condition frequently experience contradictory feelings and needs. In this context, core aspects of spirituality such as meaning and purpose in life are often questioned. DESIGN: A review and synthesis of qualitative empirical research was undertaken in order to seek a deeper understanding of the spiritual aspects of patients' experiences of infertility. METHODS: An aggregative synthesis was conducted according to Saini & Shlonsky (2012), using thematic analysis. RESULTS: A total of 26 studies included female, male and couples. Settings revealed interviewees in different infertility phases such as diagnosis, Assisted Reproductive Technologies (ARTs) and following fertility treatments. Two main themes emerged: spiritual needs and spirituality as a coping resource for infertility. CONCLUSION: Infertility affects the holistic existence of the couples. This adversity awakens spiritual needs along with unmet needs of parenthood. Coping strategies incorporating spirituality can enhance the ability of couples to overcome childlessness and suffering. RELEVANCE TO CLINICAL PRACTICE: Infertile couples' experiences of infertility may offer an opportunity for spiritual care particularly related to the assessment of spiritual needs and the promotion of spiritual coping strategies. Effective holistic care should support couples in overcoming and finding meaning in this life and health condition
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