Sensory Measurements: Coordination and Standardization

Do sensory measurements deserve the label of “measurement”? We argue that they do. They fit with an epistemological view of measurement held in current philosophy of science, and they face the same kinds of epistemological challenges as physical measurements do: the problem of coordination and the problem of standardization. These problems are addressed through the process of “epistemic iteration,” for all measurements. We also argue for distinguishing the problem of standardization from the problem of coordination. To exemplify our claims, we draw on olfactory performance tests, especially studies linking olfactory decline to neurodegenerative disorders

High capacity silicon anodes enabled by MXene viscous aqueous ink

The ever-increasing demands for advanced lithium-ion batteries have greatly stimulated the quest for robust electrodes with a high areal capacity. Producing thick electrodes from a high-performance active material would maximize this parameter. However, above a critical thickness, solution-processed films typically encounter electrical/mechanical problems, limiting the achievable areal capacity and rate performance as a result. Herein, we show that two-dimensional titanium carbide or carbonitride nanosheets, known as MXenes, can be used as a conductive binder for silicon electrodes produced by a simple and scalable slurry-casting technique without the need of any other additives. The nanosheets form a continuous metallic network, enable fast charge transport and provide good mechanical reinforcement for the thick electrode (up to 450 µm). Consequently, very high areal capacity anodes (up to 23.3 mAh cm−2) have been demonstrated

Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids

To progress from the laboratory to commercial applications, it will be necessary to develop industrially scalable methods to produce large quantities of defect-free graphene. Here we show that high-shear mixing of graphite in suitable stabilizing liquids results in large-scale exfoliation to give dispersions of graphene nanosheets. X-ray photoelectron spectroscopy and Raman spectroscopy show the exfoliated flakes to be unoxidized and free of basal-plane defects. We have developed a simple model that shows exfoliation to occur once the local shear rate exceeds 10(4) s(-1). By fully characterizing the scaling behaviour of the graphene production rate, we show that exfoliation can be achieved in liquid volumes from hundreds of millilitres up to hundreds of litres and beyond. The graphene produced by this method performs well in applications from composites to conductive coatings. This method can be applied to exfoliate BN, MoS2 and a range of other layered crystals

Experimental aspects of dissipation force microscopy

Experimental aspects of measuring dissipation on atomic scale using large-amplitude dynamic force microscopy are discussed. Dissipation versus distance curves reveal that long- and short-range forces contribute to the dissipation. The decay length of short-range contributions is found to be close to that of the tunneling current. The dependence of dissipation on the bias voltage and on the oscillation amplitude is presented. Atomic-scale lateral variations of dissipation are discussed; and the role of the atomic constitution of the tip for quantitative results is pointed out

Contrast inversion in nc-AFM on Si(111)7 x 7 due to short-range electrostatic interactions

Contrast inversion in nc-AFM on Si(111)7 x 7 is observed at positive sample bias. Corner holes appear as protrusions and adatoms as holes. The application of negative bias voltages causes drastic changes in the atomic constrast. Frequency shift vs distance curves show evidence of short-range, voltage-dependent forces. These observations indicate that short-range electrostatic forces are important for atomic-scale contrast in nc-AFM

Dissipation mechanisms studied by dynamic force microscopies

Tile dissipation mechanisms of contact force microscopy on solid surfaces are related to the fast motion during the slip process. Different degrees of freedom can be excited, such as phonons or electronic excitations. The dissipation mechanisms of dynamic force microscopy (DFM) were recently investigated due to the improvement in large amplitude DFM, also called dissipation force microscopy. Experimental methods to determine damping with DFM will be discussed. When an electrical field is applied between probing tip and sample, damping is observed, which depends on voltage. This type of damping is related to mirror charges, which move in tile sample and/or tip because of the motion of the cantilever. When the contact potential is compensated, this long-range part is minimized. Under these conditions, only short-range damping can be measured, which appears at distances of about 1nm and increases exponentially with closer separation. Recent models of this type of damping show, that there might be a relationship to the local phonon density