This review summarizes recent advances in the area of tribology based on the outcome of a Lorentz Center workshop surveying various physical, chemical and mechanical phenomena across scales. Among ...the main themes discussed were those of rough surface representations, the breakdown of continuum theories at the nano- and microscales, as well as multiscale and multiphysics aspects for analytical and computational models relevant to applications spanning a variety of sectors, from automotive to biotribology and nanotechnology. Significant effort is still required to account for complementary nonlinear effects of plasticity, adhesion, friction, wear, lubrication and surface chemistry in tribological models. For each topic, we propose some research directions.
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•Expressions are found for moments of breakthrough curves for river tracer tests with exchange with the hyporheic zone governed by a memory function.•The coefficient of skewness for memory ...function-based models decreases with distance.•River transport transient storage model has a quasi-analytical closed-form solution.
Practical simulation of solute transport in river corridors often relies on one-dimensional transport models with solute flux between river and hyporheic zone governed by a mass exchange term, perhaps most generally expressed using the ‘memory function’ formalism. While expressions for temporal moments of solute breakthrough curves (BTCs) are available for a number of such models, those for memory function forms are not, to our knowledge. Here we report closed-form BTC temporal moment expressions for memory function forms, found by exploiting the connection to phase exposure-dependent exchange (PhEDEx) formulations. We use these results to investigate the general capability of the memory function form to accommodate specific scaling of river tracer temporal moments reported in the literature, and we apply the method to identification of parameters in application to two recent tracer tests. The applications involve a simple numerical solution to the memory function river corridor transport model calibrated using measured temporal moments of the tracer test BTCs. The numerical model is validated only for the classical case of the transient storage model without lateral inflow, the analytical solution for which we adapt from the Lassey solution for mobile-immobile exchange in porous media. It should be noted that the temporal moments results obtained here in the context of river corridor transport also apply to one-dimensional transport in two-domain (mobile-immobile) porous media, when governed by a two-domain memory function model.
Pre-asymptotic dispersion revisited Gurung, Deviyani; Aghababaei, Mohammad; Ginn, Timothy R.
Advances in water resources,
01/2024, Volume:
183
Journal Article
Since the outbreak of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the control of virus spread has remained challenging given the pitfalls of the current diagnostic tests. ...Nevertheless, RNA amplification techniques have been the gold standard among other diagnostic methods for monitoring clinical samples for the presence of the virus. In the current paper, we review the shortcomings and strengths of RT-PCR (real-time polymerase chain reaction) techniques for diagnosis of coronavirus disease (COVID)-19. We address the repercussions of false-negative and false-positive rates encountered in the test, summarize approaches to improve the overall sensitivity of this method. We discuss the barriers to the widespread use of the RT-PCR test, and some technical advances, such as RT-LAMP (reverse-transcriptase-loop mediated isothermal amplification). We also address how other molecular techniques, such as immunodiagnostic tests can be used to avoid incorrect interpretation of RT-PCR tests.
Effects of nano-clay on weight loss of wood-plastic composites (WPC) by five fungi were studied. Nanoclay particles of 20 to 50 nm size were applied at 2, 4, and 6% WPC of 0,90 g/cm³ density. The ...white-rot fungi Physisporinus vitreus, Pleurotus ostreatus and Trametes versicolor as well as the brown-rot species Antrodia vaillantii and Coniophora puteana were used. Mass loss tests were conducted according to the European standard. The highest (3,2%) and lowest (0,2%) mass losses were produced by T. versicolor and P. vitreus in the control and 6%-nanoclay treatments, respectively. Obviously the weight loss of WPC depends on the fungus species. Although weight losses were extremely low, nano-clay considerably inhibited the growth of wood-deteriorating fungi. Mass loss correlated with water absorption.
Many cases of aseptic meningitis or meningoencephalitis, unresponsive to antimicrobial treatments, have been reported recently in patients with established/new-onset central nervous system (CNS) ...inflammatory demyelinating diseases (CNSIDDs). Given the higher probability of infectious etiologies, CNSIDDs are rarely considered among the differentials in meningitis or meningoencephalitis cases. We gathered and tabulated cases of non-infectious, steroid-responsive meningitis or meningoencephalitis associated with neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein-associated disease (MOGAD). This conceptual review highlights the need to bolster routine infectious workups with immunological workups in cases of meningoencephalitis or meningitis where potential autoimmune etiologies can be suspected. Although differentiating CNSIDDs with meningeal involvement from infectious meningitis may not substantially affect acute treatment strategies, long-term management and follow-up of the two are entirely different. We also discuss future research directions and hypotheses on how CNSIDDs may be associated with meningitis-like presentations, e.g. overlapping glial fibrillary acidic protein astrocytopathy or autoimmune encephalitis, alterations in regulatory T-helper cells function, and undetected viral agents.
The fracture surface characterization, such as the fracture roughness, is essential to flow and heat transport through the fracture in the geothermal, oil, and gas reservoirs stimulation by hydraulic ...fracturing. This research presents an experimental approach to assess the correlation between the fracture roughness and mode I fracture toughness (KIc) of the granitic rock with different grain sizes, which is crucial in geothermal reservoirs. Three types of granite with the same mineralogical compositions but fine, medium, and coarse-grained structures were selected and prepared. Fracture toughness values were measured using a novel specimen called ENDB (Edge Notched Disc Bend), in which a cracked disc shape specimen was loaded in three-point bending. The photogrammetric method was used to estimate the value and distribution of surface roughness after ENDB testing and investigate the relationship between fracture morphology and fracture toughness. Based on the experiments, a clear correlation between the roughness and fracture toughness was observed in the three investigated granite types with different grain sizes. The FPZ around the crack tip, tortuosity, intergranular, and transgranular cracks were examined to study the effect of grain size on fracture toughness and roughness precisely. The results show that by increasing the grain size, KIc and surface roughness increased. The results also showed that the roughness parameter for the three types of rocks in the direction of the crack growth path is greater than the direction perpendicular to the crack growth path.
●The effect of grain size on the fracture toughness and roughness was considered.●Three types of granite with identical mineralogical compositions but varying grain sizes were selected.●The ENBD sample was utilized to conduct fracture toughness testing under mode I loading.●The photogrammetric method was employed to measure the roughness of the crack surface, and MATLAB code was developed to calculate surface roughness parameters.●FPZ was estimated based on thin section analysis to adequately describe the effect of grain size.
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