An analytical approach to converting vibration signal to combustion characteristics of homogeneous charge compression ignition engines

Homogeneous charge compression ignition (HCCI) is a promising low-temperature combustion technique for low-emission internal combustion engines. Unlike conventional engines, HCCI lacks a direct ignition control mechanism, necessitating closed-loop combustion control. This study proposes a phenomenological-based, cost-effective, and non-intrusive approach using vibration data analysis to determine essential combustion parameters. Experiments were conducted on a single-cylinder research engine with an accelerometer attached to the engine head. The engine operation envelope covered the whole engine’s operating area in naturally aspirated HCCI mode. Wavelet analysis revealed that combustion-related frequencies centered around 500 Hz, independent of operating conditions. The correlation-seeking analysis included peak acceleration amplitude and its crank angle with peak heat release rate (HRR) data. The peak HRR location was accurately identified within one degree when vibration amplitude exceeded the 100 m/s2 threshold. This encompassed 98.5% of the analyzed combustion cycles. The peak HRR prediction accuracy had a maximum error below 21% and was suitable to monitor reaction rates, especially in incomplete combustion and high ringing cycles.© 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

THE SPECIFICITY OF MODERNISED HISTORICAL OBJECTS UPON THE EXAMPLE OF MERCAT DEL BORN IN BARCELONA AND THE HALA TARGOWA (MARKET HALL) IN GDAŃSK

In both the above mentioned market halls the intervention of new function into the antique tissue was in similar scope as well as was chosen the same rule to open the exposition of findings. However, the different functions – one commercial and the other cultural – as well as different kinds of ownership determined the area of exposition. The cultural function and municipal owner of Mercat del Born will allow most probably for full scope findings exposition, but the maintained retail trade in Market Hall and the private owner of oriented mentality restricts the exhibition and actually, try to close it down. To design the modernization of historic buildings is probably the most difficult and not for professional reasons only but for very specific, marked with conflict of interests atmosphere of designing and then construction. In the creation of such undertaking essential is professionalism and independence of conservator’s service. That enables to achieve the equilibrium between the conservation program and expectations of traders. This problem is very delicate, as well as the role of architect being the mediator between conservator and the traders. The evidence of architect’s effectiveness is to convince traders that archeological exhibition created at retail square expense is a guarantee of their trade success

A modular design approach to polymer-coated ZnO nanocrystals

Summary: Hybrid materials based on inorganic nanocrystals with organic polymers feature peculiar and fascinating properties and various applications. However, there is still a need for simple synthesis procedures that provide precise control over the polymer/nanocrystal microstructure of these materials. Herein, a novel organometallic approach to polymer-coated ZnO nanocrystals was developed. The presented method merges the initial ring-opening polymerization of ϵ-caprolactone mediated by an organozinc alkoxide initiator and an air-promoted transformation of the resulting macromolecular organozinc species. This one-pot procedure results in quantum-sized ZnO crystals with a core diameter of ca 3 nm coated by poly(ϵ-caprolactone) covalently bonded to the surface. Overall, the ability to create well-defined hybrid composites should provide a unique ability to access various nanosystems