Sigmoidal NMFD: Convolutional NMF with Saturating Activations for Drum Mixture Decomposition

In many types of music, percussion plays an essential role to establish the rhythm and the groove of the music. Algorithms that can decompose the percussive signal into its constituent components would therefore be very useful, as they would enable many analytical and creative applications. This paper describes a method for the unsupervised decomposition of percussive recordings, building on the non-negative matrix factor deconvolution (NMFD) algorithm. Given a percussive music recording, NMFD discovers a dictionary of time-varying spectral templates and corresponding activation functions, representing its constituent sounds and their positions in the mix. We observe, however, that the activation functions discovered using NMFD do not show the expected impulse-like behavior for percussive instruments. We therefore enforce this behavior by specifying that the activations should take on binary values: either an instrument is hit, or it is not. To this end, we rewrite the activations as the output of a sigmoidal function, multiplied with a per-component amplitude factor. We furthermore define a regularization term that biases the decomposition to solutions with saturated activations, leading to the desired binary behavior. We evaluate several optimization strategies and techniques that are designed to avoid poor local minima. We show that incentivizing the activations to be binary indeed leads to the desired impulse-like behavior, and that the resulting components are better separated, leading to more interpretable decompositions.

PROSPECTS FOR THE APPLICATION OF COPPER MELTING SLAG IN ROAD CONSTRUCTION

The article discusses the option of strengthening the soils of the roadbed of highways with complex binders based on granular slag of copper smelting production and air lime. The characteristics of the investigated slag, photomicrographs of its surface, as well as the chemical and phase compositions are presented. A detailed description of the X-ray diffractogram of the studied slag with the processing of the obtained reflections using the ICDD PDF-2 database is presented. Calculations of hydrolytic equilibria were carried out using the main phases found from the data of X-ray phase analysis. It was found by the calculation method that at pH = 11-12 in the lime-slag mixture decomposition of iron silicates and aluminosilicates occurs with the formation of gels of iron and aluminum hydroxides, as well as amorphous silica. On the basis of the obtained complex binder, standard samples of strengthened soil based on loam were made and tested to determine the physical and mechanical properties. The results of the experiments carried out create an opportunity for obtaining hardened soils based on a complex mineral binder with a compressive strength of up to 2.2 MPa.

Управление детонационным горением посредством предварительной подготовки газовой смеси

Using a detailed kinetic model of chemical interaction, numerical investigation of influence of a preliminary preparation of a stoichiometrical hydrogen-air mixture (decomposition of some volumes of molecular hydrogen and molecular oxygen gases into atomic gases) on characteristics of a propagating detonation wave has been carried out. It has been obtained that the preliminary partial dissociation of the gas mixture results in an essential decrease of the detonation cell size and a small increase of the self-sustained detonation wave propagation velocity. Due to the established detonation combustion features, preliminary preparation of the mixture can be used to prevent destruction of a detonation wave in channels with both a single transverse barrier and a barrier domain.

KINETICS OF A BINARY MIXTURE DECOMPOSITION IN RELATIONTO THE EFFECTS ON OIL RESERVOIR

The kinetic constants of the decomposition reaction of an aqueous solution of a binary mixture used for thermal-pressure induced impact on the bottomhole zone during stimulation of oil inflow are determined. The obtained constants allow predicting the effects of pressure and temperature growth in the reaction zone. A mathematical model is proposed that makes it possible to describe the kinetics of the reaction taking into account the escape of gas.

Investigation on Thermal and Kinetic Characteristics During Pyrolysis and Co-Pyrolysis of Recovered Fuels Obtained From Municipal Solid Waste in China

Alternative fuels, such as municipal solid waste (MSW) tend to play an increasingly important role in Chinese energy supply. Gasifying fuels derived from MSW have the potential of covering a significant part of the future demand on gasification capacities. However, their pyrolysis behaviour was not clear due to that the reactions during co-pyrolysis of the MSW serval fractions have not yet been fully investigated. In this paper, thermal behavior of pork, polypropylene and their blends were investigated by thermogravimetry under pyrolysis conditions via the non-isothermal thermogravimetric analysis. The pyrolysis and co-pyrolysis kinetics characteristics of the waste samples was investigated at a temperature range of 50 to 1000 °C with the heating rate of rate of 10, 20, 40 °C·min−1 and for particle sizes less than 74 μm. The results indicated that pyrolysis rate of pork was hindered by polypropylene. Negative synergistic effects on mixture decomposition was observed. Weight loss of mixture were lower than that calculated from individual samples for pork and polypropylene. The apparent activation energy were obtained through Kissinger and Ozawa methods for the samples. The results indicated that more energy for blends to be decomposed during co-pyrolysis.