Was it Uruguay or Coffee? The causes of the beef jerky industry’s decline in southern Brazil (1850 – 1889)

What caused the decline of the beef jerky’s production in Brazil? The main sustenance for slaves, beef jerky was the most important industry in southern Brazil. Nevertheless, by 1850, producers were already worried that they could not compete with Uruguayan industry. Traditional interpretations impute the decline to labor markets differences in productivity, since Brazil used slaves while Uruguay had abolished slavery in 1842. Recent research also raises the possibility of a Brazilian “Dutch Disease”, resulting from the coffee exports boom. We test both hypothesis and argue that Brazilian production’s decline was associated with structural changes in demand for low quality meat. Trade protection policies created disincentives for Brazilian producers to increase productivity and diversify its cattle industry

IMPLEMENTATION OF TWO-CAVITY METHOD FOR MEASURING THE FLOW RESISTIVITY OF ACOUSTIC MATERIAL

Acoustic materials are characterized according to their macroscopic and microscopic properties. The sound absorption co-efficient and the air-flow resistivity are of paramount importance among those used to describe the acoustic behaviour of materials. There are several methods developed for measuring the air-flow resistivity of acoustic material. The aim of this paper is to study the existing static flow resistivity measurement methods and then accordingly implement a suitable indirect method based on standard impedance tube. The flow resistivity measurements are carried out for additive manufactured ABS (Acrylonitrile butadiene styrene) sample, foam and glass fibre using the two-cavity method. There are certain similarities observed in their results. Further analysis of the raw impedance data is carried out and conclusions are drawn pertaining to the performance and feasibility of the implemented method

A Performance Study on Indirect Static Flow Resistivity Measurement Methods for Acoustic Materials

Various empirical models have emphasized the dependence of sound absorption coefficient on static airflow resistivity, and thus its measurement becomes essential. In this paper, the two-cavity and two-thickness indirect acoustic methods are implemented based on a standard impedance tube for evaluating the static flow resistivity of foam. A comparison is made between the resistivity results obtained by the two-cavity and two-thickness method , and later validated with results of an alternating air-flow test setup which is developed as per the ISO 9053 guidelines. Further, the empirical relations are utilized to estimate the absorption coefficientfrom measured values ​​of flow resistivity and are compared with measured absorption coefficient in an impedance tube . The results discussed in this study presents the feasibility and suitability of the indirect acoustic methods for evaluating the flow resistivity

Implementation of Two-cavity Method for Measuring the Flow Resistivity of Acoustic Material

Acoustic materials are characterized according to their macroscopic and microscopic properties. The sound absorption co-efficient and the air-flow resistivity are of paramount importance among those used to describe the acoustic behaviour of materials. There are several methods developed for measuring the air-flow resistivity of acoustic material. The aim of this paper is to study the existing static flow resistivity measurement methods and then accordingly implement a suitable indirect method based on standard impedance tube. The flow resistivity measurements are carried out for additive manufactured ABS (Acrylonitrile butadiene styrene) sample, foam and glass fibre using the two-cavity method. There are certain similarities observed in their results. Further analysis of the raw impedance data is carried out and conclusions are drawn pertaining to the performance and feasibility of the implemented method

A Performance Study on Indirect Static Flow Resistivity Measurement Methods for Acoustic Materials

Abstract: Various empirical models have emphasized the dependence of sound absorption coefficient on static airflow resistivity, and thus its measurement becomes essential. In this paper, the two-cavity and two-thickness indirect acoustic methods are implemented based on a standard impedance tube for evaluating the static flow resistivity of foam. A comparison is made between the resistivity results obtained by the two-cavity and two-thickness method, and later validated with results of an alternating air-flow test setup which is developed as per the ISO 9053 guidelines. Further, the empirical relations are utilized to estimate the absorption coefficient from measured values of flow resistivity and are compared with measured absorption coefficient in an impedance tube. The results discussed in this study presents the feasibility and suitability of the indirect acoustic methods for evaluating the flow resistivity