Abstract
Outgassing of PTH PCBs at different stages of PCB production was studied with a modified IEC outgassing test, Draft June 1985, now included in IEC 326–2 Amendment No. 2, January 1988. Outgassing rate from single PTHs was quantitatively measured with a U‐tube manometer as a pressure of expanded steam escaped. Some technological parameters were taken into account and different comparisons were made: PCB production stage (drilling, copper and solder plating, reflowing) vs. outgassing rate, laminate thickness vs. outgassing rate. The contributions to outgassing of PTHs through PCB production, especially from copper and tin‐lead plating, are seen. On PCBs, drilled with different drills and soldered unpopulated on wave and drag soldering machines, outgassing faults were assessed. By multiple regression the relation between outgassing faults, hole wall roughness and plated copper thickness was calculated.
The Second Brazilian Printed Circuit Association Seminar will take place in Rio de Janeiro from 21–23 September 1988. Papers will be presented on the following topics:
The purpose of this study is to provide the estimates of returns to schooling using consistent methodology and comparable set of data for a long time horizon for a country…
Abstract
Purpose
The purpose of this study is to provide the estimates of returns to schooling using consistent methodology and comparable set of data for a long time horizon for a country undergoing economic transition. Second, the paper aims to verify if returns to schooling in Poland were pro-cyclical or counter-cyclical.
Design/methodology/approach
The paper is based on the human capital theory in estimating the wage returns to years of schooling controlling additionally for unemployment rates at a regional level. Data come from a collection of Polish individual LFS waves for the period 1995–2017.
Findings
Returns to schooling in Poland were increasing until 2006 and declining afterwards unveiling the supply side effects domination. The estimates suggested counter-cyclicality of returns in Poland.
Research limitations/implications
Using LFS data made it impossible to control for ability bias therefore it is possible that the estimates are somewhat biased (the literature however suggests that the extent of the bias is likely to be small). It might still be argued that using consistent methodology for the whole period of analysis still offers valuable insight into returns evolution.
Originality/value
This paper finds a reversal of returns trend after 2006 suggesting the period after accession to EU exhibited a supply side effect domination. The findings on counter-cyclicality of returns to education in Poland have not yet been documented in the literature.