Numerical characterization of silicon DC electro-osmotic pumps: the role of the micro channel geometry

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.A numerical analysis of silicon DC open channel EOPs is presented to show which parameters should be taken into account in the design of these devices. Particular attention is paid to the influence of the channel cross-section geometry on pump behavior, especially in relation to the electrical properties of the fluid. Rectangular and trapezoidal, micro and nano channels chemically etched on silicon wafers are considered and a broad range of operative conditions are analyzed. In order to make all the results available, two user-friendly correlations that predict the characteristic curves of the pumps are given as functions of the relevant parameters. The EOP model used to obtain the results is explained extensively, as well as the method used to solve it. A brief discussion on the domain in which it applies is also presented

Electro-osmotic flows inside triangular microchannels

This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section

Myofascial trigger points alter the modular control during the execution of a reaching task: a pilot study

Myofascial trigger points (TP) constitute a conundrum in research and clinical practice as their etiopathogenesis is debated. Several studies investigating one or few muscles have shown that both active and latent TP causes an increased muscle activity, however the influence of TP on modular motor control during a reaching task is still unclear. Electromyographic signals, recorded from the muscles of the shoulder girdle and upper arm during a reaching task, were decomposed with Non-Negative Matrix Factorization algorithm. The extracted matrices of motor modules and activation signals were used to label the muscles condition as dominant or non-dominant. The presence of latent and active TP was detected in each muscle with manual examination. Despite a similar muscle activity was observed, we found that muscles with active TP had increased weighting coefficients when labeled in the dominant condition. No influences were found when muscles were in the non-dominant condition. These findings suggest that TP altered the motor control without co-contraction patterns. As a preliminary evidence, the present results suggest that the increased weighting coefficients in presence of TPs are associated with an alteration of the modular motor control without affecting the dimensionality of motor modules for each individual and reciprocal inhibition

Lightning performance evaluation of Italian 150 kV sub-transmission lines

A significant majority of overhead transmission lines' (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150kVItalian OHL, namely, its backflashover rate (BFOR), carried out by means of anATP-EMTP-based Monte Carlo procedure. Among other features, the procedure makes use of a simplified pi-circuit for line towers' grounding system, allowing a very accurate reproduction of transient behaviours at a very low computational cost. Tower grounding design modifications, aimed at improving the OHL lightning performance, are also proposed and discussed

Effectiveness of Trigger Point Manual Treatment on the Frequency, Intensity, and Duration of Attacks in Primary Headaches: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: A variety of interventions has been proposed for symptomatology relief in primary headaches. Among these, manual trigger points (TrPs) treatment gains popularity, but its effects have not been investigated yet. Objective: The aim was to establish the effectiveness of manual TrP compared to minimal active or no active interventions in terms of frequency, intensity, and duration of attacks in adult people with primary headaches. Methods: We searched MEDLINE, COCHRANE, Web Of Science, and PEDro databases up to November 2017 for randomized controlled trials (RCTs). Two independent reviewers appraised the risk-of-bias (RoB) and the grading of recommendations, assessment, development, and evaluation (GRADE) to evaluate the overall quality of evidence. Results: Seven RCTs that compared manual treatment vs minimal active intervention were included: 5 focused on tension-type headache (TTH) and 2 on Migraine (MH); 3 out of 7 RCTs had high RoB. Combined TTH and MH results show statistically significant reduction for all outcomes after treatment compared to controls, but the level of evidence was very low. Subgroup analysis showed a statistically significant reduction in attack frequency (no. of attacks per month) after treatment in TTH (MD -3.50; 95% CI from -4.91 to -2.09; 4 RCTs) and in MH (MD -1.92; 95% CI from -3.03 to -0.80; 2 RCTs). Pain intensity (0-100 scale) was reduced in TTH (MD -12.83; 95% CI from -19.49 to -6.17; 4 RCTs) and in MH (MD -13.60; 95% CI from -19.54 to -7.66; 2RCTs). Duration of attacks (hours) was reduced in TTH (MD -0.51; 95% CI from -0.97 to -0.04; 2 RCTs) and in MH (MD -10.68; 95% CI from -14.41 to -6.95; 1 RCT). Conclusion: Manual TrPs treatment of head and neck muscles may reduce frequency, intensity, and duration of attacks in TTH and MH, but the quality of evidence according to GRADE approach was very low for the presence of few studies, high RoB, and imprecision of results

Borazineâ CF3â Adducts for Rapid, Room Temperature, and Broad Scope Trifluoromethylation

A fluoroformâ derived borazine CF3â transfer reagent is used to effect rapid nucleophilic reactions in the absence of additives, within minutes at 25â °C. Inorganic electrophiles spanning seven groups of the periodic table can be trifluoromethylated in high yield, including transition metals used for catalytic trifluoromethylation. Organic electrophiles included (hetero)arenes, enabling Câ H and Câ X trifluoromethylation reactions. Mechanistic analysis supports a dissociative mechanism for CF3â transfer, and cation modification afforded a reagent with enhanced stability.A trifluoromethylating matter: A stable fluoroformâ derived reagent facilitates the nucleophilic trifluoromethylation of a broad array of inorganic and organic electrophiles (E) at room temperature. The reaction scope includes 18 inorganic elements, nucleophilic aromatic substitution, and CF3â addition to carbonyl and imine compounds. Kinetic analysis supports a dissociative mechanism.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/1/anie201711316_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/2/anie201711316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141342/3/anie201711316-sup-0001-misc_information.pd

Borazineâ CF3â Adducts for Rapid, Room Temperature, and Broad Scope Trifluoromethylation

A fluoroformâ derived borazine CF3â transfer reagent is used to effect rapid nucleophilic reactions in the absence of additives, within minutes at 25â °C. Inorganic electrophiles spanning seven groups of the periodic table can be trifluoromethylated in high yield, including transition metals used for catalytic trifluoromethylation. Organic electrophiles included (hetero)arenes, enabling Câ H and Câ X trifluoromethylation reactions. Mechanistic analysis supports a dissociative mechanism for CF3â transfer, and cation modification afforded a reagent with enhanced stability.Von Fluoroform abgeleitet wurde ein stabiles Reagenz für nukleophile Trifluormethylierungen anorganischer und organischer Elektrophile (E) bei Raumtemperatur. Das Reaktionsspektrum umfasst 18 anorganische Elemente, nucleophile aromatische Substitutionen sowie CF3â â Additionen an Carbonylverbindungen und Imine. Kinetische Studien sprechen für einen dissoziativen Mechanismus.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/1/ange201711316-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/2/ange201711316.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141871/3/ange201711316_am.pd

Thermal delay of drop coalescence

We present the results of a combined experimental and theoretical study of drop coalescence in the presence of an initial temperature difference T[subscript 0] between a drop and a bath of the same liquid. We characterize experimentally the dependence of the residence time before coalescence on T[subscript 0] for silicone oils with different viscosities. Delayed coalescence arises above a critical temperature difference T[subscript c] that depends on the fluid viscosity: for T[subscript 0] > T[subscript c], the delay time increases T[subscript 0] [superscript 2/3] as for all liquids examined. This observed dependence is rationalized theoretically through consideration of the thermocapillary flows generated within the drop, the bath and the intervening air layer.National Science Foundation (U.S.) (Grant CMMI-1727565)National Science Foundation (U.S.) (Grant DMS-1614043