Acoustic field restoration and control in closed technical areas by applying the synergy of numerical and analytical models

The noise in the industrial companies is caused by operation of the mechanisms and equipment and during various technological operations. The effect of these excitation sources on the acoustic field is very different and the control of these processes with a purpose to reduce the noise is usually very complicated and sometimes impossible. The main objective of this work was to analyze how the FE and analytical models synergy uses such type of tasks. Using the described methodology, which is based on consistent application of numerical and analytical models, and the limited experimental research data can significantly reduce the costs of investigation for the study and evaluation of acoustic fields generated by a variety of sources in closed technical space

Low frequency traffic noise prediction and modelling of noise barriers using FEM

The paper is a part of investigation near one of the busiest Lithuanian roads with big percentage of heavy traffic where the spectrum of traffic noise and efficiency of existing noise screens also enhancement of them have been studied. The paper presents use of finite element method (FEM) for traffic noise prediction at low (16-200 Hz) frequencies also for modelling of noise barriers and enhancement of them by adding tops (heads). Acoustic field transformation simulation model is prepared within COMSOL software. Model is verified according investigation in situ (measurements) and deals with divergence loss, diffraction from obstacles, absorption and reflection from surfaces of cylindrical sound waves solving Helmholtz equation. Numerical prediction showed that investigated additional tops can improve effectiveness of noise barrier either at low frequencies (Leq(16-200 Hz)) up to ~2 dB and up to ~7 dB at discrete frequencies

Investigation of three-layered rectangular corrugated cardboard package resistance to dynamic loads

This paper presents the values of dynamics loads determined during experimental investigations as multi-layered corrugated cardboard packages were subjected to loading mass m and underwent shock loads. Existence of such loadings cause undesirable mechanical and exploitation damage to packages

The crack analysis in monitoring procedures of Seaport pier concrete constructions

The geodetic and geotechnical techniques were accepted for monitoring and measurement of unique hydro-technical structures, i.e. of pier stability. The designed monitoring system for pier damage prevention has been realized at the experimental object of Klaipeda State Seaport. Cracks of pier concrete constructions were identified, measured and continuously observed by the application of crack-gauges for experimental measurement. The analysis of the results shows that cracks of chosen locations depend upon meteorological conditions, such as, for example, temperature. It influences the width of cracks in the pier concrete. The relations were obtained according to the created monitoring system of hydro-technical structure which estimates the influence of cracks of pier concrete to the structural damages

Kukurūzų grūdų tamprio nustatymas impulsinės apkrovos metodu

Nuimant drėgnus (apie 35% drėgnio) kukurūzų grūdus, iki 40% jų gali būti sužalojama. Grūdų sužalojimas labiausiai priklauso nuo jų tamprio. Buvo nustatyta, kad grūdų drėgnis kinta išilgai šerdies, kartu kinta ir jų tampris. Tyrimais pagrįsta, kad grūdų tampris priklauso nuo jų drėgnio ir kinta nuo 35 MPa iki 85 MPa. Straipsnyje pateiktas metodas grūdų tampriui nustatyti impulsine apkrova. Naudojant šį metodą galima įvertinti realias kukurūzų burbuolių kūlimo sąlygas ir parinkti optimalius technologinius parametrus naujų kūlimo metodų kūrimuiBy harvesting of wet maize (moisture content of grains about 35%) up to 40% grains can be damaged. Grain damage mostly depends on their Young’s modulus. It was established, that moisture content of grains varies by length of the cobs the grain Young’s modulus varies as well. It was estimated, that Young’s modulus of grains changed with moisture content of the grains and varied from 35 MPa to 85 MPa. The introduced in the article method of estimating grain Young’s modulus on basis of impact load enables to regard real condition of threshing, to choose optimal technological parameters for generating new methods of threshingKauno technologijos universitetas, [email protected] Didžiojo universitetasŽemės ūkio akademij

State v. Torres Appellant\u27s Brief Dckt. 40198

https://digitalcommons.law.uidaho.edu/not_reported/2040/thumbnail.jp

Benzino transportavimo rizikos analizė

Straipsnyje nagrinėjamos benzino transportavimo rizikos problemos. Plačiau nagrinėtas benzino transportavimas benzinvežiais. Pagrindinis šio darbo tikslas – benzinvežių keliamos rizikos įvertinimas ir valdymas Lietuvos keliuose. Šiam tikslui buvo sudarytas benzino transportavimo rizikos matematinis modelis ir apskaičiuota benzinvežių keliama rizika visuose magistraliniuose ir krašto keliuose. Išnagrinėti įvairūs benzinvežių maršrutų parinkimo scenarijai ir su tuo susijęs galutinės rizikos kitimas Lietuvos keliuose. Aptartos informacinių technologijų, mažinančių riziką, taikymo perspektyvosThe paper analyses risk problems related with petrol transportation. Petrol transportation by tank trucks is analyzed more detaily. Tank trucks caused risk estimation and control on Lithuania roads are the main goal of the work. For this purpose mathematical model of petrol transportation risk was developed and risk of arterial and domestic roads caused by tank trucks was evaluated. Various scenarios of tank trucks route selection and therewith related final risk variation on Lithuanian roads was analyzed. Perspectives of application of information technologies reducing risk are discussedKauno technikos kolegija, [email protected] technologijos universitetas, [email protected] technologijos universitetas, [email protected] Didžiojo universiteta

Investigation of packages resistance under dynamics loads

Experimental tests were carried out, which led to determination of resistance of packages to free fall drop as well as resistance of plastic packages to deformation during compression under the influence of vibrations. Packages of different size and shape were used during testing. Graphic dependences of compression loads and deformations of the packages were obtained and the maximum values of compression loads and deformations after free fall drop tests were established. The obtained results and conclusions of investigations are applied for the determination of characteristics and qualities of packaging materials and packaging designKauno technologijos universitetasVytauto Didžiojo universiteta