Calculation of Acoustic Efficiency of Exhaust Silencers for Automotive Internal Combustion Engines

Insertion losses as the main characteristic that mathematically describes the acoustic efficiency of a noise silencer has been considered. This characteristic shows the reduction of noise generated by its source, in particular by the internal combustion engine’s exhaust system, at the control point as a silencer use result. Has been presented a mathematical description of the insertion losses, and have been considered parameters necessary for calculating this characteristic. Has been demonstrated the analytical dependence of impedance for the sound emission by the exhaust system’s end hole from the coefficient of acoustic waves reflection by this hole. The performed analysis of the widely used formulas for calculating the coefficient of sound reflection by the end hole has showed their insufficient accuracy for project designs performing. Have been proposed calculation dependences providing high accuracy for calculations of the reflection coefficient modulus, and the attached length of the channel end hole without a flange in the entire range of the existence of plane waves in it. It has been shown that the end correction of this hole at ka = 0 is 0.6127, and not 0.6133, as it was mistakenly believed until now in world acoustics. Has been proposed a method for calculation the exhaust noise source internal impedance. This method more accurately, in comparison with the already known ones, describes the acoustic processes in the internal combustion engine’s exhaust manifold, thanks to increases the accuracy of calculation the silencer acoustic efficiency, that allows develop the silencer at the early stages of the design of an automotive internal combustion engine.

Model for the Suspensions Separation Process in Hydrodynamic Filters with a Rotating Filter Element

The possibility of applying the probabilistic-statistical method for theoretical calculation of characteristics related to suspensions separation in self-cleaning hydrodynamic filters with a rotating filter element has been demonstrated. It has been shown that the change in characteristics of the suspensions separation in hydrodynamic filters with a rotating filter element can be satisfactorily described based on equations of diffusion type, in particular, using the Fokker–Planck–Kolmogorov equation. The main parameters of the separation process in hydrodynamic filters with a rotating filter element have been determined.

Development of an Express Method for Studying the Toxicity of Modern Cable Compounds’ Combustion Products

In case of fire, combustible materials and products made on their basis have a decisive role in the development of combustion, formation and spread of foreground risks. Normative legal documents restrict the use of fire hazardous materials, but it is impossible to exclude their use completely. In case of fire, in addition to flame and high temperatures are formed smoke and toxic gaseous products of combustion. The basis of the most common products is polyvinyl chloride - one of the most common fire hazardous materials, whose production volumes have only increased in recent years. In the course of this work, an express method has been developed and tested for the qualitative and quantitative determination of toxic substances contained in combustion products of plastic compounds based on polyvinyl chloride.

Element Imbalance among Workers during Solar CellProduction

The solar cell production requires additional methods for workers protection, as well as certain conditions and requirements for the premises to meet them. Solar cell factories are equipped with clean rooms, which meet high environmental and worker protection requirements. Research laboratories often do not meet such protection conditions. Therefore, most often the working conditions in such laboratories are insufficient. In two research laboratories was conducted a study for the elemental composition of hair of workers engaged in the solar cell production and the production methods improvement. As a result of the study it was found an increased content of rare and rare earth metals in some workers’ body and hair. This study allows assess the level of production processes impact on the worker in the studied activity area.

Human Environment Acoustics in Bauman Moscow State Technical University: Yesterday, Today, Tomorrow

The history of "Environmental Acoustics" research area development in the activities of the Bauman Moscow State Technical University’s "Ecology and Industrial Safety" chair in general from the end of the nineteenth century to the present time has been described. Much attention is paid to the activities of E.Ya. Yudin (as the creator of the technical acoustics scientific school at the chair) and his students as well. Have been presented the main areas of carried out at the chair research works (both theoretical and practical), related to problems of noise and vibration reduction. Have been considered the issues of technical acoustics teaching in the framework of the recently created "Environmental Acoustics" master's program, as well as the prospects for this area development at the chair in the near future.

Model for the Dynamics of the Gas Medium Temperature Growth in the Initial Stage of a Fire in Buildings

Within the framework of the integral mathematical model for the building fire’s initial stage, the increments of the gas medium temperature in the initial stage of a fire development in buildings have been determined, and estimates for these increments have been presented. The dependence between the gas medium temperature’s relative increment and the burn-up rate’s average value has been established, and an estimated formula for the relative temperature difference over a given time period has been obtained.

Analysis of Transport Accidents’ Causes at the Fuel and Energy Complex’s Facilities

Have been presented the results of the analysis of industrial accidents related to traffic emergencies at the Fuel and Energy Complex’s facilities. Using the risk analysis methods have been identified root causes of an incident, and their level has been established. The frequently used phrase "the driver has lost operating the vehicle" does not contain information to identify the root causes of the accident and requires explanations for further development of measures to eliminate and prevent these causes.

Strategy for the Management of Pulp and Paper Industry’sWaste Containing Lignosulfonates

The pulp and paper industry’s multi-tonnage liquid waste is spent cooking liquor containing lignosulfonates, which disposal and processing remains one of the most complex environmental and technological problems, which should be solved. Lignosulfonates have unique colloidal-chemical properties, which determines their high resource potential. However, lignosulfonates’ composition instability often does not provide the properties and indicators set by the consumer. Changing market conditions require constant waste monitoring and modification, that prevents the widespread lignosulfonates use in industrial practice. In this paper, the causes for the formation of lignin-containing waste and its impact on the environment are considered. A strategy for lignosulfonates utilization has been developed, as well as promising methods for these wastes processing and disposal, which will expand the use of lignosulfonates and reduce the pulp and paper industry negative impact on the environment.

Recommendations on Occupational Risk Assessment Matrix Development

The matrix method is often used for occupational risk assessment. In this paper have been considered the matrix method’s use features, as well as have been highlighted its advantages and disadvantages. Have been presented recommendations on the risk matrix development, and criteria for categorization of occupational risk’s attributes – the effect consequences severity of hazard and its feasibility. The proposed approach to consequences severity categorization is accorded with rules and regulations regarding the severity of harm to human health, which in return facilitates mitigation the degree of uncertainty and subjectivity of the assessment results. The grading of categories for hazard feasibility is based on well-known scientific and practical approaches. Has been performed the generalization of scientific data on the hazard feasibility categorization, and have been proposed universal criteria descriptors, which allow assess the considered hazard objectively and all round, and determine the necessary category for this hazard feasibility. It has been pointed to subjective perception of categories names in final estimating of occupational risk levels, and has been proposed to use the concepts of occupational risk levels, which based on the priority relating to risk respond measures. The proposed approaches facilitate increase of quality and effectiveness of matrix method use in estimating of occupational risk levels.

Consideration of Trigger Mechanisms of Natural and Man-made Disasters in the Earth’s Geospheres

Have been presented the trigger mechanisms of accidents emergence in different Earth's Geospheres. Has been given the definition for the trigger mechanism of initiation of changes in geosystems. The threshold value for the starting (initiating) trigger signal has been detailed. The graphic representation of work of a trigger system has been presented, and its functioning has been explained. Various ways for switching of a trigger system have been revealed. The principles of the trigger impact on the troposphere, the lower part of the Earth's atmosphere, initiation of cyclones and earthquakes, and descent of avalanches and glacial mudflows have been detailed.