Towards altering sound frequency at will by a linear meta-layer with time-varying and quantized properties

Wave frequency is a critical parameter for applications ranging from human hearing, acoustic non-reciprocity, medical imaging to quantum of energy in matter. Frequency alteration holds the promise of breaking limits imposed by the physics laws such as Rayleigh’s criterion and Planck–Einstein relation. We introduce a linear mechanism to convert the wave frequency to any value at will by creating a digitally pre-defined, time-varying material property. The device is based on an electromagnetic diaphragm with a MOSFET-controlled shunt circuit. The measured ratio of acoustic impedance modulation is up to 45, much higher than nonlinearity-based techniques. A significant portion of the incoming source frequency is scattered to sidebands. We demonstrate the conversion of audible sounds to infrasound and ultrasound, respectively, and a monochromatic tone to white noise by a randomized MOSFET time sequence, raising the prospect of applications such as super-resolution imaging, deep sub-wavelength energy flow control, and encrypted underwater communication.

Charge of clustered microparticles measured in spatial plasma afterglows follows the smallest enclosing sphere model

The plasma-induced charge of non-spherical microparticles is a crucial parameter in complex plasma physics, aerosol science and astrophysics. Yet, the literature describes this charge by two competing models, neither of which has been experimentally verified or refuted. Here we offer experimental proof that the charge on a two-particle cluster (doublet) in the spatial afterglow of a low-pressure plasma equals the charge that would be obtained by the smallest enclosing sphere and that it should therefore not be based on its geometrical capacitance but rather on the capacitance of its smallest enclosing sphere. To support this conclusion, the size, mass and charge of single particles (singlets) and doublets are measured with high precision. The measured ratio between the plasma-afterglow-induced charges on doublets and singlets is compared to both models and shows perfect agreement with the predicted ratio using the capacitance of the smallest enclosing sphere, while being significantly dissimilar to the predicted ratio based on the particle’s geometrical capacitance.

A Microvalve Module with High Chemical Inertness and Embedded Flow Heating for Microscale Gas Chromatography

This paper reports a multi-valve module with high chemical inertness and embedded flow heating for microscale gas chromatography (µGC) systems. The multi-valve module incorporates a monolithically microfabricated die stack, polyimide valve membranes, and solenoid actuators. The design incorporates three valves within a single module of volume 30.2 cm3, which is suitable for the small form factor of µGC systems. The die stack uses fused silica wafers and polyimide valve membranes that enhance chemical inertness. The monolithic die stack requires only three lithographic masks to pattern fluidic microchannels, valve seats, and thin-film metal heaters and thermistors. The performance of fabricated multi-valve modules is compared to a commercial valve in tests using multiple volatile organic compounds, including alkanes, alcohols, ketones, aromatic hydrocarbons, and phosphonates. The valves show almost no distortion of chromatographic peaks. The experimentally measured ratio of flow conductance is 3.46 × 103, with 4.15 sccm/kPa in the open state and 0.0012 sccm/kPa in the closed state. The response time is <120 ms.

Permeability of membranes in the liquid ordered and liquid disordered phases

The functional significance of ordered nanodomains (or rafts) in cholesterol rich eukaryotic cell membranes has only begun to be explored. This study exploits the correspondence of cellular rafts and liquid ordered (Lo) phases of three-component lipid bilayers to examine permeability. Molecular dynamics simulations of Lo phase dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and cholesterol show that oxygen and water transit a leaflet through the DOPC and cholesterol rich boundaries of hexagonally packed DPPC microdomains, freely diffuse along the bilayer midplane, and escape the membrane along the boundary regions. Electron paramagnetic resonance experiments provide critical validation: the measured ratio of oxygen concentrations near the midplanes of liquid disordered (Ld) and Lo bilayers of DPPC/DOPC/cholesterol is 1.75 ± 0.35, in very good agreement with 1.3 ± 0.3 obtained from simulation. The results show how cellular rafts can be structurally rigid signaling platforms while remaining nearly as permeable to small molecules as the Ld phase.

An Evaluation of Eggshell Waste/Waste Paper Mechanical Properties as Composite Paper

Paper as a material, is useful. For this reason, the paper industry has contributed widely to the economy. This is also true for advancement in the technology for recycled papers. Paper fibre or paper pulp however is depleting due to extensive deforestation and loggings which in turn leads to problems such as global warming. Further, eggshell waste is a material found to be useful to produce papers. As such, this study intends to find out the possibilities of using eggshell waste and waste papers to produce papers. To carry out the research, the optimum ratio of fibre in the paper pulp was determined by the maximum strength of recycled paper produced. Eggshell waste was collected from a food court. The eggshells were then separated from their membrane, dried in the sun and grinded. It was then mixed with paper pulp according to the measured ratio. The study found that paper from a combination of eggshell fibre waste against waste paper was able to be produced and the optimum ratio was 2:8 because it had the highest tensile strength. The eggshell waste can be used as a material that enhanced the mechanical properties of recycled paper.

Basic principles of modeling microalgae's photobiosynthesis

The paper lists the classic and modern views on the microalgae's culture growth, which constitute a new paradigm of modeling photobiosynthesis. Microalgae are considered as lower obligate photoautotrophs capable of oxygenic photosynthesis, characterized by the separation of photochemical and enzymatic processes. A model scheme of the light and dark reactions conjugation in microalgae is proposed. The process of biosynthesis of cell biochemical structures from minerals is carried out due to the energy of high-potential forms of high-energy compounds (NADP·H, ATP). It is shown that the microalgae's growth can be considered as a set of energyexchange reactions. The concept of the absence of limiting microalgae's growth by environmental factors is proposed. The rate of biomass synthesis is determined by the reduced flow density of the energy or plastic substrate to the key enzyme. Also, for convenience in practical terms, productivity can be expressed through the biochemical measured ratio of structural and reserve forms of biomass. In any case, the dependence of the rate of biomass synthesis on the value of the reduced flux density is described by linear splines, which allows you to clearly set the switching point of the limiting factor and obtain simple mathematical solutions.

Nucleon and Δ electromagnetic form factors

The unitary and analytic model for nucleons works very well. The model for spin [Formula: see text] baryons can predict static parameters for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. We prepared the scheme how to construct the model also for [Formula: see text] nucleon resonance. It was used to describe transition form factor [Formula: see text] and the experimentally measured ratio [Formula: see text] with the help of relations for magnetic dipole transition and charge quadrupole form factors.

PROBING THE ANOMALOUS COUPLINGS OF THE TOP QUARK WITH GLUON AT THE LHC AND TEVATRON

In this paper, we study the sensitivity of the fraction of [Formula: see text] events arising from gluon–gluon fusion to the chromoelectric and chromomagnetic dipole moments (CEDM and CMDM) as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron. The sensitivity of measured charged asymmetry at the LHC to CEDM and CMDM is also studied. We find that at the Tevatron and the LHC, nonzero values of CMDM could suppress the [Formula: see text] production rate. It is shown that the ratio of [Formula: see text] at the Tevatron is more sensitive to CEDM and CMDM than the LHC case. The presence of CEDM always increases the contribution of gluon–gluon fusion process in top pair rate at the Tevatron and LHC. Except for a small range of CMDM, the presence of CEDM and CMDM can increase the fraction of gluon–gluon fusion at the Tevatron and LHC. The measured ratio of [Formula: see text] at the Tevatron is used to derive bounds on the chromoelectric and chromomagnetic dipole moments as well as the total and differential [Formula: see text] cross-sections at the LHC and Tevatron, and the measured charged asymmetry at the LHC. The combination of [Formula: see text] and σ LHC provides stringent limits on CMDM and CEDM.