Pyrimidine-Based Push–Pull Systems with a New Anchoring Amide Group for Dye-Sensitized Solar Cells

New donor–π–acceptor pyrimidine-based dyes comprising an amide moiety as an anchoring group have been designed. The dyes were synthesized by sequential procedures based on the microwave-assisted Suzuki cross-coupling and bromination reactions. The influence of the dye structure and length of π-linker on the photophysical and electrochemical properties and on the photovoltaic effectiveness of dye-sensitized solar cells was investigated. An increase in efficiency with a decrease in the length of π-linker was revealed. The D1 dye with only one 2,5-thienylene-linker provided the highest power conversion efficiency among the fabricated dye sensitized solar cells.

Effectiveness of Push–Pull Systems to Fall Armyworm (Spodoptera frugiperda) Management in Maize Crops in Morelos, Mexico

Chemical control is the main method used to combat fall armyworm in maize crops. However, its indiscriminate use usually leads to a more complex scenario characterized by loss of its effectiveness due to the development of resistance of the insect pest, emergence of secondary pests, and reduction of the populations of natural enemies. For this reason, efforts to develop strategies for agroecological pest management such as Push–Pull are increasingly growing. In this context, the present study was carried out to evaluate field effectiveness of Push–Pull systems for S. frugiperda management in maize crops in Morelos, Mexico. In a randomized block experiment, the incidence and severity of S. frugiperda, the development and yield of maize were evaluated in nine Push–Pull systems and a maize monoculture. The Push–Pull systems presented incidence/severity values lower than those of the monoculture. Morphological development and maize yield in the latter were lower than those of most Push–Pull systems. Mombasa—D. ambrosioides, Mulato II—T. erecta, Mulato II—C. juncea, Tanzania—T. erecta and Tanzania—D. ambrosioides systems presented higher yields than those of monocultures.

Synthesis of tetrasubstituted thiophenes starting from amino mercaptoacrylates and a-brominated acetamides

: Some thiophenic derivatives show important biological activity or are used as intermediates in organic synthesis. For this reason, it is very important to develop new synthesis procedures with good yields and using few synthesis steps. The present work offers an over-view of the method for obtaining substituted thiophenes reported in the literature, and the synthetic procedures used from push-pull systems. In this work, we present the synthesis of 14 new tetrasubstituted thiophenes starting from amino mercaptoacrylates and a-brominated acetamides, derived from furoyl and benzoylacetonitrile, respectively. Best yields (66 to 85%) were obtained through ultrasonic irradiation. Combined use of spectroscopic methods and elementary analysis was used for characterization of all the compounds.

Influence of (de)protonation on the photophysical properties of phenol-substituted diazine chromophores: experimental and theoretical studies

In this contribution, a series of seven new push-pull systems has been designed by combining a protonable diazine heterocycle (pyrimidine/pyrazine) with a deprotonable phenol unit through various -conjugated linkers (phenylene,...

Pull Production Systems

This chapter aims to organize knowledge about pull production systems by presenting the underlying concepts of lean manufacturing as for its origin, principles, and relations with PPC. Pull production is one the fundamental principles of lean manufacturing, and its implementation can bring positive impacts. For such a purpose, sequential and mixed supermarket pull systems stand out in which the integration between pull production systems and PPC and its various levels is a main subject of discussion. The JIT model or Kanban method and hybrid systems, such as conwip and lung-drum-string theory, are mechanisms for managing pull production systems. Finally, a pull production system implementation is presented for illustration purposes. At the end of this chapter, it is expected that skills are developed by readers, which are going to assist them in using the tools presented to model production systems and aid decision-making processes.