Multidiszciplináris Tudományok

A faktoriális kísérlettervezés és különböző regressziós modellek vizsgálata optimális tapasztalati képletek generálásához

2025-09-21T12:27:46+02:00

A jelenkor iparának egyik legfontosabb kihívása, hogy a különböző gyártási, feldolgozási folyamatokat minél pontosabban, megbízhatóbban, költséghatékonyabban optimalizálni tudja. A vevők által támasztott piaci igények folyamatosan változnak: egy-egy termék gyártási ciklusa, fejlesztési üteme lerövidül, variációik széles spektrumon húzódnak, melyekre, ha a gyártó nem képes időben reagálni, könnyen elmaradhat a konkurensekhez képest a piaci versenyben. A fenntarthatósági elvárások szintén komoly elvárásokat támasztanak. Ezen kihívások teljesítéséhez elengedhetetlen a gyártási folyamatok, paramétereik folyamatos monitorozása, elemzése. Ehhez célszerű olyan matematikai modelleket használni, melyek segítségével előre is jelezni tudjuk, hogy egy adott paraméterkombináció milyen hatással lesz a kívánt eredményre, például a gépgyártás-technológiában a felületi érdességre. Ebben a tanulmányban egy korábban elvégzett kísérletsorozat eredményeinek felhasználásával mutatjuk be a faktoriális kísérlettervezés és különböző regressziós modellek módszerét, majd összehasonlító elemzést végzek, hogy meghatározzam, melyik modell közelíti leginkább a mért eredményeket.

PCBA to PCBA, a depopulation comparison

2025-10-14T14:34:55+02:00

In order to increase metal recovery from discarded printed circuit board assemblies, an additional preprocessing step where its electronic components are presorted before comminution and metallurgy is suggested. The first step in this process is depopulation where the electronic components are removed from the board. However, currently no practical apples to apples comparison has been performed. Therefore, six depopulation methods (both mechanical and thermal) were directly compared on both qualitative and quantitative indicators and evaluated using a multi-criteria analysis. The mechanical methods were faster less energy intensive than the thermal methods but produced lower quality products and had issues with scaling. Overall the best found method was using a pneumatic hammer due to its simplicity and effectiveness.

An investigation into the evolution of the deformation state in single point incremental forming

2025-10-04T20:54:10+02:00

Single point incremental sheet metal forming (SPIF) is a novel and flexible forming technology that has been emerged and spread its application for the production of various customized sheet metal parts. This alternative of incremental sheet metal forming (ISF) has gained a good reputation compared to the traditional forming methods in case of low production volume. However, the deformation state is still unclear in the different part regions. Therefore, in the current investigation, a finite element analysis has been devoted to study the evolution of the stress triaxiality during the SPIF process of pure aluminium alloy Al 1050. The triaxial state has strong dependence on the located cone-forming regions indicating a dominate stress state.

Investigation of one-column and pressure-swing distillation of ethanol-water mixture

2025-09-21T12:12:20+02:00

In this study, the separation of ethanol-water mixture was investigated using the Unisim Design® simulation software with the NRTL activity coefficient model. Two different constructions were investigated: a single high-pressure distillation column (traditional process) and a pressure-swing distillation (PSD) system. It is a relatively difficult separation procedure, because the components make a non-ideal, azeotropic mixture. With the one-column, traditional system the maximum reachable ethanol concentration in the product is equal with the azeotropic value. With the pressure-swing distillation (PSD) system higher ethanol concentration could be achievable in the product, however it has disadvantages (for example the higher costs). During this study the reachable bottom product ethanol concentration is 93 mole%. Some sensitivity analysis was made: the increasing pressure in the second column improves the ethanol mass flow and reduces energy demand in heat exchangers. These results show that pressure-swing distillation is a more efficient alternative technique for ethanol purification over the azeotropic composition in the viewpoint of energy demand in the condensers and reboilers and in the viewpoint of ethanol mass flow in the product.

The history of lending and factors that can affect lending but are difficult to measure

2025-09-07T15:36:24+02:00

I set two goals when preparing this study. First, I wanted to examine the historical processes characteristic of lending, how people in different historical periods viewed borrowing, and what was characteristic of this area. I conducted a historical review from Hammurabi to the present day, focusing on events that I considered important. I then examined the factors that can be linked to lending and loan defaults, but which are difficult to measure and for which there is no generally accepted method. Within this area, I focused on financial culture, inclusion, and resilience, drawing on OECD research in this field. Overall, I concluded that these factors play an important role and that it may be advisable to take some of them into account in lending and credit assessment.