Towards understanding the critical heat flux for industrial applications

Understanding CHF is of an upmost importance in many industries, especially in the design and operation of boilers, nuclear power plants, cryogenic systems, etc. Due to safety issues related to the nuclear power plants, and the adaptation of CHF as the limiting criterion of power generation, it is important to understand the mechanisms of CHF relevant to nuclear systems operation. Moreover, CHF is expected to occur during transients than steady-state conditions. Therefore, knowledge of transient CHF is of great importance for the safety evaluation of nuclear reactors under transient condition. In this paper, the existing CHF experimental and modeling studies are discussed in order to understand the phenomena leading to CHF. Also, the effect of transient conditions on CHF for nuclear fuels has been evaluated.     

Thermodynamic perturbation theory for fused sphere hard chain fluids using nonadditive interactions

A model is developed for the equation of state of fused chains based on Wertheim thermodynamic perturbation theory and nonadditive size interactions. The model also assumes that the structure (represented by the radial distribution function) of the fused chain fluid is the same as that of the touching hard sphere chain fluid. The model is completely based on spherical additive and nonadditive size interactions. The model has the advantage of offering good agreement with simulation data while at the same time being independent of fitted parameters. The model is most accurate for short chains, small values of Delta (slightly fused spheres) and at intermediate (liquidlike) densities.     

Influence of branch content on the microstructure of blends of linear and octene-branched polyethylene: a MD simulation study

Microstructure of linear low-density polyethylene (LLDPE) with linear high-density polyethylene (HDPE) is investigated by molecular dynamics (MD) simulation. The branch content of LLDPE was varied from 10 to 60 branches/1000 C. An equimolar mixture of each of the two polymers is simulated in the NVT ensemble at 500 K and at average experimental densities of the two polymer melts. Initially, chains of LLDPE and HDPE were completely mixed and evolution of conformations with time was monitored. The blends were found to microphase separate when the branch content of LLDPE exceeded 30 branches/1000 C. At 40 branches/1000 C, the two polymers displayed partial microphase separation and complete microphase separation was observed at 60 branches/1000 C. Substantial short-range order and mismatch of molecular conformations is observed in the microphase-separated systems.     

Modelling the CPI using a lognormal diffusion process and implications on forecasting inflation

The Maximum Likelihood estimator is used within a lognormaldiffusion process and closed form analytical solutions are obtained.The monthly CPI forecasts are estimated for the period between1970 and 2002. The quarterly estimates of inflation rates areobtained from monthly forecasts rather than from quarterly data.This has significantly improved the estimates of inflation rates.The model also produced a superior fit as compared to randomwalk and GARCH(p,q)-M models. The adopted approach is foundto be simple, economical and generally suitable for modellingstochastic processes that reflect aggregation over time stemmingfrom many factors, and in which the transition path betweenconsecutive states is relatively smooth.     

A study of hand vibration on chipping and grinding operators,part I: Vibration acceleration levels measured on pneumatic tools used in chipping and grinding operations

This paper describes the acceleration measurements and data analysis aspect of a comprehensive multidisciplined field study of several hundred chipper and grinder workers using pneumatic hand-held tools. Engineering testing of a sampling of these tools indicated that for a frequency range of 6·3 Hz to 1000 Hz, overall acceleration levels between 2000 m/s² and 24 000 m/s² were measured on the chisels and levels between 37 m/s² and 350 m/s² were measured on the handles of chipping hammers. Hand grinder acceleration levels ranged from 6 m/s² to 21 m/s².     

Thymoquinone Loaded Topical Nanoemulgel for Wound Healing: Formulation Design and In-Vivo Evaluation

Thymoquinone is a natural bioactive with significant therapeutic activity against multiple ailments including wound healing. The poor aqueous solubility and low skin permeability limit its therapeutic efficacy. The present investigation aimed to improve the biopharmaceutical attributes of thymoquinone to enhance its topical efficacy in wound healing. A nanoemulsion-based hydrogel system was designed and characterized as a nanotechnology-mediated drug delivery approach to improve the therapeutic efficacy of thymoquinone, utilizing a high-energy emulsification technique. The black seed oil, as a natural home of thymoquinone, was utilized to improve the drug loading capacity of the developed nanoemulsion system and reduced the oil droplet size to <100 nm through ultrasonication. The influence of formulation composition, and the ultrasonication process conditions, were investigated on the mean globule size and polydispersity index of the generated nanoemulsion. Irrespective of surfactant/co-surfactant ratio and % concentration of surfactant/co-surfactant mixture, the ultrasonication time had a significant (p < 0.05) influence on the mean droplet size and polydispersity index of the generated nanoemulsion. The developed nanoemulgel system of thymoquinone demonstrated the pseudoplastic behavior with thixotropic properties, and this behavior is desirable for topical application. The nanoemulgel system of thymoquinone exhibited significant enhancement (p < 0.05) in skin penetrability and deposition characteristics after topical administration compared to the conventional hydrogel system. The developed nanoemulgel system of thymoquinone exhibited quicker and early healing in wounded Wistar rats compared to the conventional hydrogel of thymoquinone, while showing comparable healing efficacy with respect to marketed silver sulfadiazine (1%) cream. Furthermore, histopathology analysis of animals treated with a developed formulation system demonstrated the formation of the thick epidermal layer, papillary dermis along with the presence of extensive and organized collagen fibers in newly healed tissues. The outcome of this investigation signifies that topical delivery of thymoquinone through nanoemulgel system is a promising candidate which accelerates the process of wound healing in preclinical study.     

The Healing Capability of Clove Flower Extract (CFE) in Streptozotocin-Induced (STZ-Induced) Diabetic Rat Wounds Infected with Multidrug Resistant Bacteria

Treatment of diabetic foot ulcer (DFU) is of great challenge as it is shown to be infected by multidrug resistant bacteria (MDR bacteria). Sixty four bacterial isolates were isolated from DFU cases; antibiotic susceptibility tests were carried out for all of them. One bacterial isolate (number 11) was shown to resist the action of 8 out of 12 antibiotics used and was identified by both a Vitek-2 system and 16S rRNA fingerprints as belonging to Proteus mirabilis, and was designated Proteus mirabilis {"type":"entrez-nucleotide","attrs":{"text":"LC587231","term_id":"1917123988"}}LC587231 (P. mirabilis). Clove flower extract (CFE) inhibited distinctively the P. mirabilis bacterium obtained. GC-MS spectroscopy showed that this CFE contained nine bioactive compounds. The effect of CFE on wound healing of Type 1 diabetic albino rats (Rattus norvegicus) was studied. The results indicated that topical application of CFE hydrogel improved wound size, wound index, mRNA expression of the wound healing markers (Coli1, MMP9, Fibronectin, PCNA, and TGFβ), growth factor signaling pathways (PPAR-α, PGC1-α, GLP-1, GLPr-1, EGF-β, EGF-βr, VEGF-β, and FGF-β), inflammatory cytokine expression (IL8, TNFα, NFKβ, IL1β, and MCP1), as well as anti-inflammatory cytokines (IL4 & IL10), pro-apoptotic markers (FAS, FAS-L, BAX, BAX/BCL-2, Caspase-3, P53, P38), as well as an antiapoptotic one (BCL2). Furthermore, it improved the wound oxidative state and reduced the wound microbial load, as the cefepime therapy improved the wound healing parameters. Based on the previous notions, it could be concluded that CFE represents a valid antibiotics alternative for DFU therapy since it improves diabetic wound healing and exerts antibacterial activity either in vitro or in vivo.     

Preparation and Characterization of Disulfiram and Beta Cyclodextrin Inclusion Complexes for Potential Application in the Treatment of SARS-CoV-2 via Nebulization

Disulfiram (DS), known as an anti-alcoholism drug, has shown a potent antiviral activity. Still, the potential clinical application of DS is limited by its low water solubility and rapid metabolism. Cyclodextrins (CDs) have been widely used to improve the solubility of drugs in water. In this study, five concentrations of hydroxypropyl β-cyclodextrin (HP) and sulfobutyl ether β-cyclodextrin (SBE) were used to form inclusion complexes of DS for enhanced solubility. Solutions were freeze-dried, and the interaction between DS and CD was characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). In addition, the nebulization properties of the DS–CD solutions were studied. The aqueous solubility of DS increased significantly when loaded to either of both CDs. The phase solubility of both complexes was a linear function of the CD concentration (A_L type). Furthermore, physicochemical characterization studies showed a potent inclusion of the drug in the CD–DS complexes. Aerosolization studies demonstrated that these formulations are suitable for inhalation. Overall, the CD inclusion complexes have great potential for the enhancement of DS solubility. However, further studies are needed to assess the efficacy of DS–CD inclusion complexes against SARS-CoV-2 via nebulization.     

A General Strategy to Enhance Donor-Acceptor Molecules Using Solvent-Excluding Substituents

While organic donor-acceptor (D-A) molecules are widely employed in multiple areas, the application of more D-A molecules could be limited because of an inherent polarity sensitivity that inhibits photochemical processes. Presented here is a facile chemical modification to attenuate solvent-dependent mechanisms of excited-state quenching through addition of a β-carbonyl-based polar substituent. The results reveal a mechanism wherein the β-carbonyl substituent creates a structural buffer between the donor and the surrounding solvent. Through computational and experimental analyses, it is demonstrated that the β-carbonyl simultaneously attenuates two distinct solvent-dependent quenching mechanisms. Using the β-carbonyl substituent, improvements in the photophysical properties of commonly used D-A fluorophores and their enhanced performance in biological imaging are shown.