Revisiting the Assignment of Innocent and Non-Innocent Counter ions in Lanthanide(III) Solution Chemistry

Lanthanides are found in critical applications from display technology to renewable energy. Often these rare earth elements are used as alloys or functional materials, yet the access to them are trough solution processes. In aqueous solution the rare earths are found predominantly as trivalent ions and charge balance dictates that counter ions are present. The fast ligand exchange and lack of directional bonding in lanthanides complexes has led to questions regarding the speciation of Ln3+ solvates in the presence of various counter ions, and to the distinction between innocent = non-coordinating, and non-innocent = coordinating counter ions. There is limited agreement as to which counter ions that belong to each group, which lead to this report. By using Eu3+ luminescence, it was possible to clearly distinguish between coordinating and non-coordinating ions. To interpret the results it was required to bridge the descriptions of ion pairing and coordination. The da-ta—in form of Eu3+ luminescence spectra and luminescence lifetimes from solutions with varying concentrations of acetate, chloride, nitrate, fluoride, sulfate, perchlorate and triflate—were contrasted to those obtained with ethylenediaminetet-raaceticacid (EDTA), which allowed for the distinction between three Ln3+-anion interaction types. It was possible to con-clude which counter ions are truly innocent (e.g. ClO4- and OTf-), and which clearly coordinate (e.g. NO3- and AcO-). Finally, the considerate amount of data from systems studied under similar conditions allowed the minimum perturbation arising from inner sphere or outer sphere coordination in Eu3+ complexes to be identified.

Highlighting the processing versatility of a silicon phthalocyanine derivative for organic thin-film transistors

Silicon phthalocyanine (SiPc) derivatives have recently emerged as promising materials for n-type organic thin-film transistors (OTFTs) with the ability to be fabricated either by solid state or solution processes through...

MENINGKATKAN KEMAMPUAN PENALARAN MATEMATIS SISWA MELALUI PEMBELAJARAN BERBASIS MASALAH MATERI PELUANG KELAS XI TKRO-A SMKN 4 JAKARTA

This study aims to improve students' mathematical reasoning skills through the application of problem-based learning in class XI TKRO-A SMK Negeri 4 Jakarta which involves 6 students. This research is classroom action research which is carried out in three cycles and each cycle consists of four stages, namely planning, implementation, observation, and reflection. Students are given a test at the end of each cycle to measure their mathematical reasoning ability. The results showed that learning mathematics through the application of problem-based learning can improve mathematical reasoning abilities from pre-study of 39.34 in the first cycle of 67.65 in the second cycle of 72.24 to 74.08 in the third cycle. The conclusion of this study is that the application of problem-based learning can improve students' mathematical reasoning abilities. Improved mathematical reasoning abilities include aspects: the ability to predict answers and solution processes, use patterns and relationships to analyze mathematical situations, draw logical conclusions from statements, and provide explanations using models, facts and relationships in solving problems. The number of students whose mathematical reasoning scores reached or exceeded 75 also increased. In the preliminary study, there were no students whose mathematical reasoning test scores reached or exceeded 75, while in the first cycle as many as 41.18% students, in the second cycle increased to 61.77% students, and in the third cycle increased to 82.35% students. ABSTRAKPenelitian ini bertujuan untuk meningkatkan kemampuan penalaran matematis siswa melalui penerapan pembelajaran berbasis masalah di kelas XI TKRO-A SMK Negeri 4 Jakarta yang melibatkan 6 siswa. Penelitian ini adalah penelitian tindakan kelas (classroom action research) yang dilaksanakan dalam tiga siklus dan tiap siklus terdiri dari empat tahapan, yaitu perencanaan, pelaksanaan, observasi, dan refleksi. Siswa diberikan tes pada setiap akhir siklus untuk mengukur kemampuan penalaran matematis. Hasil penelitian menunjukkan bahwa pembelajaran matematika melalui penerapan pembelajaran berbasis masalah dapat meningkatkan kemampuan penalaran matematis dari pra penelitian sebesar 39,34 siklus I sebesar 67,65 siklus II sebesar 72,24 menjadi 74,08 pada siklus III. Kesimpulan penelitian ini adalah bahwa penerapan pembelajaran berbasis masalah dapat meningkatan kemampuan penalaran matematis siswa. Peningkatan kemampuan penalaran matematis meliputi aspek: kemampuan memperkirakan jawaban dan proses solusi, menggunakan pola dan hubungan untuk menganalisis situasi matematika, menarik kesimpulan logis dari pernyataan, dan memberikan penjelasan dengan menggunakan model, fakta dan hubungan dalam menyelesaikan soal. Jumlah siswa yang nilai penalaran matematisnya mencapai atau melebihi 75 juga mengalami peningkatan. Pada penelitian pendahuluan belum terdapat siswa yang nilai tes penalaran matematisnya mencapai atau melebihi 75, sedangkan pada siklus I sebanyak 41,18% siswa, pada siklus II meningkat menjadi 61,77% siswa, dan pada siklus III meningkat menjadi 82,35% siswa.

Comparing interactive evolutionary multiobjective optimization methods with an artificial decision maker

Solving multiobjective optimization problems with interactive methods enables a decision maker with domain expertise to direct the search for the most preferred trade-offs with preference information and learn about the problem. There are different interactive methods, and it is important to compare them and find the best-suited one for solving the problem in question. Comparisons with real decision makers are expensive, and artificial decision makers (ADMs) have been proposed to simulate humans in basic testing before involving real decision makers. Existing ADMs only consider one type of preference information. In this paper, we propose ADM-II, which is tailored to assess several interactive evolutionary methods and is able to handle different types of preference information. We consider two phases of interactive solution processes, i.e., learning and decision phases separately, so that the proposed ADM-II generates preference information in different ways in each of them to reflect the nature of the phases. We demonstrate how ADM-II can be applied with different methods and problems. We also propose an indicator to assess and compare the performance of interactive evolutionary methods.

Mass action model of solution activity via speciation by solvation and ion pairing equilibria

Solutes and their concentrations influence many natural and anthropogenic solution processes. Electrolyte and solution models are used to quantify and predict such behavior. Here we present a mechanistic solution model based on mass action equilibria. Solvation and ion pairing are used to model speciated solute and solvent concentrations such that they correlate to a solution’s vapor pressure (solvent activity) according to Raoult’s law from dilute conditions to saturation. This model introduces a hydration equilibrium constant (Kha) that is used with either an ion dissociation constant (Kid) or a hydration modifier (m) with an experimentally determined ion dissociation constant, as adjustable parameters to fit vapor–liquid equilibrium data. The modeled solvation equilibria are accompanied by molecular dynamics (MD) studies that support a decline in the observed degree of solvation with increased concentration. MD calculations indicate this finding is a combination of a solvent that solvates multiple solutes, and changes in a solute’s solvation sphere, with the dominant factor changing with concentration. This speciation-based solution model is lateral to established electrostatics-based electrolyte theories. With its basis in mass action, the model can directly relate experimental data to the modeled solute and solvent speciated concentrations and structures.

Micromolding Fabrication of Biocompatible Dry Micro-Pyramid Array Electrodes for Wearable Biopotential Monitoring

Thin dry electrodes are promising components in wearable healthcare devices. Assessing the condition of the human body by monitoring biopotentials facilitates the early diagnosis of diseases as well as their prevention, treatment, and therapy. Existing clinical-use electrodes have limited wearable-device usage because they use gels, require preparation steps, and are uncomfortable to wear. While dry electrodes can improve these issues and have demonstrated performance on par with gel-based electrodes, providing advantages in mobile and wearable applications; the materials and fabrication methods used are not yet at the level of disposable gel electrodes for low-cost mass manufacturing and wide adoption. Here, a low-cost manufacturing process for thin dry electrodes with a conductive micro-pyramidal array is presented for large-scale on-skin wearable applications. The electrode is fabricated using micromolding techniques in conjunction with solution processes in order to guarantee ease of fabrication, high device yield, and the possibility of mass production compatible with current semiconductor production processes. Fabricated using a conductive paste and an epoxy resin that are both biocompatible, the developed micro-pyramidal array electrode operates in a conformal, non-invasive manner, with low skin irritation, which ensures improved comfort for brief or extended use. The operation of the developed electrode was examined by analyzing electrode-skin-electrode impedance, electroencephalography, electrocardiography, and electromyography signals and comparing them with those measured simultaneously using gel electrodes.

Baltic Social Justice School Leaders

Social justice school leadership as a concept, while familiar in the United Kingdom, Australia, New Zealand, Canada, and the United States school leadership literature, is not widely recognized in other parts of the world. Social justice school leadership appropriately differs from one culture to another and is always context-specific to a particular school setting, great organization structure or country. However, social justice is a necessary and fundamental assumption for all educators committed to combating ignorance and the promotion of student global citizenship as a central theme of school practices. The purpose of this study was to provide understandings of ways that selected social justice school leaders from three countries; Lithuania, Latvia, and Estonia conceive of and practice social justice in leading their schools. The manuscript describes how six Baltic directors, identified by local educators on the basis of research conducted by the International School Leaders Development Network (ISLDN) as social justice school leaders, responded to interview questions related to their practice. Four directors were Latvian and one each from Lithuania and Estonia. Limitations to the study include basing conclusions upon a single (or in one case, several) interview(s) per subject and limitations on generalizability of qualitative exploratory case study. By definition, every case study is unique, limiting generalizability. Interviews were thematically analyzed using the following definition: A social justice school leader is one who sees injustice in ways that others do not, and has the moral purpose, skills, and necessary relationships to combat injustice for the benefit of all students. Findings reveal strong application of values to identify problems based on well-being of all students and their families and to work collaboratively with other educators to find solution processes to complex issues related to social justice inequities. As social justice pioneers in their countries, these principals personify social justice school leadership in countries where the term social justice is not part of scholarly discourse.

Research progress of full electroluminescent white light-emitting diodes based on a single emissive layer

Carbon neutrality, energy savings, and lighting costs and quality have always led to urgent demand for lighting technology innovation. White light-emitting diodes (WLEDs) based on a single emissive layer (SEL) fabricated by the solution method have been continuously researched in recent years; they are advantageous because they have a low cost and are ultrathin and flexible. Here, we reviewed the history and development of SEL–WLEDs over recent years to provide inspiration and promote their progress in lighting applications. We first introduced the emitters and analysed the advantages of these emitters in creating SEL–WLEDs and then reviewed some cases that involve the above emitters, which were formed via vacuum thermal evaporation or solution processes. Some notable developments that deserve attention are highlighted in this review due to their potential use in SEL–WLEDs, such as perovskite materials. Finally, we looked at future development trends of SEL–WLEDs and proposed potential research directions.

Hillslope Form and Process: History 1960− 2000+

The study of hillslopes has been dominated by the expansion of studies into process rates and mechanisms. Perhaps the greatest volume of work has been on the ‘wash’ processes of soil erosion, but there has also been significant work on the diffusive mass movements of linear and non-linear ‘creep’ that shape the convexity of hilltops, on more rapid mass movements and on solution processes. There has also been fresh work on distinctive processes in coastal, arid and cold-climate environments.Accompanying and integrated with process understanding, and made possible by ubiquitous computational power, modelling has developed from soluble mathematical simplifications to complex simulations that incorporate much of our understanding of process and climate.Particular topics that have seen significant advance include a more complete understanding of drainage density and texture, and a broadening of interest to encompass the ‘critical zone’ that constructively unifies the land surface with the lower atmosphere, the biosphere and the regolith. There has also been a change of focus towards steeplands, dominated by mass movements, supply limited removal and tectonic activity.Most recently, and now incorporated into the concept of the ‘Anthropocene’, human impact is now receiving increasing attention as we acknowledge its accelerating role in changing landscapes and their relationships.