Exploring graphitic carbon nitrides for (opto)electronic applications

Graphitische Karbonitride sind organische, kovalent gebundene, geschichtete und kristalline Halbleiter mit einer hohen thermischen und chemischen Stabilität. Diese Eigenschaften machen 2D Schichten der graphitischen Kristalle potentiell nützlich für das Ziel, Limitationen von organischen 0D Molekularen und 1D polymerischen Halbleitern zu überwinden. Trotz dieser interessanten Eigenschaften haben nur wenige Publikationen erfolgreich graphitische Karbonitride in optoelektronischen Bauteilen eingesetzt. Um die Vorteile dieser Materialien nutzbar zu machen, wurden bessere Synthesebedingungen gesucht. Die Verwendung von einem Iod-Eutektikum zeigt, dass Anionen mit einem größeren Radius als Bromid nicht für die Stabilisation von graphitischen Karbonitriden geeignet sind. Das Optimieren der Synthesebedingungen von Poly(triazin-imid)-LiBr resultiert in der Reduzierung von einem kohlenstoffreichen Zersetzungsprodukt bei vollständiger Kondensation. Das Untersuchen der elektronischen Struktur mit ab initio Berechnungen ergibt, dass der elektronische VB-CB-Übergang verboten ist. Dies resultiert daraus, dass die Zustände des obersten Valenzbandes nichtbindender Natur sind. Ein Band aus nichtbindenden Elektronen als oberstes Valenzband ist vor allem aus „lone-pair semiconductors“ aus der sechsten Hauptgruppe bekannt. In der Welt organischer Halbleiter wurde dieses Phänomen bisher nicht beobachtet. Die geringe makroskopische elektrische Leitfähigkeit der PTI-Filme wurde mit der Leitfähigkeit auf Nanoebene verglichen, woraus gefolgert werden kann, dass der Ladungsträgertransport durch den nanokristallinen Charakter an den Kristall-Kristall Übergängen gestört wird. Die elektronische Leitfähigkeit, Mobilität der Ladungsträger sowie die Ladungsträgerdichte wurden untersucht. Die Energie Niveaus legen nahe das Elektronentransport in der Präsenz von Sauerstoff möglich ist. Die erste Applikation eines kovalenten organischen Netzwerks in einer organischen lichtemittierenden Diode ist gezeigt worden.Graphitic carbon nitrides are organic covalently-bonded, layered, and crystalline semiconductors with high thermal and oxidative stability. These properties make 2D layers of graphitic carbon nitrides potentially useful in overcoming the limitations of 0D molecular and 1D polymer semiconductors. Only few reports have shown them being employed in optoelectronic applications. With the goal to find better reaction conditions that enable higher product quality from the ionothermal synthesis the size effect of anions is studied by using an iodide eutectic instead of bromide or chloride eutectic. The highest crystalline condensation product obtained is melem, revealing that the large iodide anion is not capable of stabilizing a graphitic structure. Studying the synthesis conditions of poly(triazine imide) (PTI), the best characterized graphitic carbon nitride in literature, it is revealed that the brown discoloration of the product is due to a carbon rich side product. Reduction of reaction temperature and increase of reaction time allows omittance of carbonisation. Analyzing the electronic structure with ab initio calculations one finds that the lowest energy electronic transition in PTI is forbidden due to a non-bonding uppermost valence band. A uppermost non-bonding valence band is most reminiscent of lone-pair semiconductors and unknown in the world of organic semiconductors making PTI the first organic lone-pair semiconductor. The low electrical conductivity of PTI derivatives is compared to nanoscale conductivity values. The results indicate that macroscopic conductivity is hampered by the nano-crystalline character due to charge carrier trapping at crystal interfaces. The effective mobility is in the range of amorphous organic semiconductors with an unexpectedly high carrier density. The energy levels in PTI-LiBr potentially enable environmentally stable n-transport. The first successful Application of a covalent organic framework in a organic light emitting diode is presented

A New Design Approach and Framework for Elderly Care Robots

A relatively new area within information systems is the design of robotic healthcare. This narrative review considers the question, how does one ethically design an elderly care robot? To answer this question, robot ethicists consider the ethical impact of robots, how designers ought to design robots ethically, and how a robot design ought to be, so its behaviour is ethical. The latter consideration defines another field of study, machine ethics. Machine ethicists ask, how does one design a robot information system to behave ethically? Thus, robot ethics is concerned with the ethics of design practice, whereas machine ethics is concerned with the ethics of the product designed. The findings from this narrative review point the way forward to how one can answer both questions with a new design approach that is grounded in care and professional ethics, value sensitive design, and the integration of two machine ethics schools of thought

Plagiocephaly Perception and Prevention: A Need to Intervene Early to Educate Parents

Background: Plagiocephaly is a condition where the cranium has been malformed because of external forces or premature cranial suture fusion. This study’s objective was to gather and examine data regarding parent and caregiver awareness of plagiocephaly and its potential impact on development as well as to determine their rate of concern for positional flattening. Method: A cross-sectional survey study was conducted. Categorical variables were described by frequency and proportions. The study was conducted across eight outpatient pediatric sites. Approximately 1,100 parents and caregivers were targeted. Inclusion criteria required participants to be willing to answer the questionnaire, to be 18 years of age or older, and to have an infant 12 months of age or younger. Results: There were 404 participants, most of whom were female (89.8%) and 30–39 years of age (61.1%). Nineteen children (4.7%) were reported to have plagiocephaly, torticollis, and/or muscle weakness (PTM). A greater percentage of the participants with a child with PTM knew of positional flattening or plagiocephaly (73.3%) compared to those without (53.8%). The respondents with a child with PTM had a greater concern about plagiocephaly than those without (p = .03). Many of the respondents (65.3%) would use a device designed to prevent plagiocephaly. Conclusion: Many parents and caregivers were unaware of plagiocephaly and its potential impact on facial symmetry. A greater percentage of the participants with a child with PTM knew of positional flattening and also had a greater concern about plagiocephaly than those without

Burn wound classification model using spatial frequency-domain imaging and machine learning.

Accurate assessment of burn severity is critical for wound care and the course of treatment. Delays in classification translate to delays in burn management, increasing the risk of scarring and infection. To this end, numerous imaging techniques have been used to examine tissue properties to infer burn severity. Spatial frequency-domain imaging (SFDI) has also been used to characterize burns based on the relationships between histologic observations and changes in tissue properties. Recently, machine learning has been used to classify burns by combining optical features from multispectral or hyperspectral imaging. Rather than employ models of light propagation to deduce tissue optical properties, we investigated the feasibility of using SFDI reflectance data at multiple spatial frequencies, with a support vector machine (SVM) classifier, to predict severity in a porcine model of graded burns. Calibrated reflectance images were collected using SFDI at eight wavelengths (471 to 851 nm) and five spatial frequencies (0 to 0.2  mm  -  1). Three models were built from subsets of this initial dataset. The first subset included data taken at all wavelengths with the planar (0  mm  -  1) spatial frequency, the second comprised data at all wavelengths and spatial frequencies, and the third used all collected data at values relative to unburned tissue. These data subsets were used to train and test cubic SVM models, and compared against burn status 28 days after injury. Model accuracy was established through leave-one-out cross-validation testing. The model based on images obtained at all wavelengths and spatial frequencies predicted burn severity at 24 h with 92.5% accuracy. The model composed of all values relative to unburned skin was 94.4% accurate. By comparison, the model that employed only planar illumination was 88.8% accurate. This investigation suggests that the combination of SFDI with machine learning has potential for accurately predicting burn severity

Evaluation of Telehealth Equipment

The aim of the project was to evaluate the use of Telehealth equipment in the homes of older community-dwelling people, and to review its social and economic impact. A mixed methods approach was adopted, involving interviews, observation and Depression Anxiety Stress Scales. The overall impression gained from participants was an enhancement to the self-perceived quality of daily functioning. Less benefit was observed by those who had been self-monitoring previously. The greatest benefit was apparent in those participants where changes in behaviours to prevent an exacerbation of their condition was possible, through either better compliance with medication, or better understanding the impact of medication on their vital signs and what that meant to their daily activities. The economic benefits appear to be linked to that social improvement. A greater focus on specific conditions and the ability to achieve stability in self-management could strengthen the evidence for targeted economic benefits

Glansbilledets skyggeside

The 19th century saw a remarkable innovation of the subject-matter of Danish altarpaintings. Frequently depicting the ministry of Christ and his Glory, these paintings have often been criticized for being skillfully executed but lacking drama, being overly sweet or even sentimental. This article argues that, in spite of the glossy façade, these paintings often engage in far more sinister topics of life and of faith. The article argues that Søren Kierkegaard’s theology offers a superb lens for gaining insights into this side of the religious painting of the so-called ‘Golden Age’ of Danish art and explores the ‘shadows of the glossy images’ through close readings of Danish altar pieces ranging from Bertel Thorvaldsen’s seminal Christ and C. W. Eckersberg’s ground-breaking Incredulity of Thomas to late 19th Century works of art by Constantin Hansen and Anton Dorph. The main argument of the article is that a negative understanding of this world and not least the constant struggle between being separated from, but needing to get (spiritually) closer to the Saviour remain very strong themes in the religious paintings throughout the 1800s, albeit mainly offered as a personal experience and not as a part of the ideal Christ figure

Glansbilledets skyggeside: Negativitetens plads i 1800-tallets religiøse kunst

The 19th century saw a remarkable innovation of the subject-matter of Danish altarpaintings. Frequently depicting the ministry of Christ and his Glory, these paintings have often been criticized for being skillfully executed but lacking drama, being overly sweet or even sentimental. This article argues that, in spite of the glossy façade, these paintings often engage in far more sinister topics of life and of faith. The article argues that Søren Kierkegaard’s theology offers a superb lens for gaining insights into this side of the religious painting of the so-called ‘Golden Age’ of Danish art and explores the ‘shadows of the glossy images’ through close readings of Danish altar pieces ranging from Bertel Thorvaldsen’s seminal Christ and C. W. Eckersberg’s ground-breaking Incredulity of Thomas to late 19th Century works of art by Constantin Hansen and Anton Dorph. The main argument of the article is that a negative understanding of this world and not least the constant struggle between being separated from, but needing to get (spiritually) closer to the Saviour remain very strong themes in the religious paintings throughout the 1800s, albeit mainly offered as a personal experience and not as a part of the ideal Christ figure

Archäologie als Empowerment: Für wen und wie? Kommentare zu wissenschaftlichem Aktivismus

On the occasion of the 10th anniversary of Forum Kritische Archäologie, the editorial collective reflected on what has been achieved and what we originally imagined for this journal. While we think that the number of contributions with a critical edge that have been published in our journal over the last 10 years is encouraging, and in many ways innovative, there is still a lot to do in one respect: to advance critical discussions in German archaeology itself. German scholarship continues to construct its discourses largely along the line of cultural-historical knowledge, and university teaching is only slowly integrating theoretical or critical perspectives. So we pondered the question of how the development of more critical approaches in German-speaking archaeology could be supported. We decided to ask authors – international and German – to write about political issues, specifically an activist archaeology. The following set of papers is conceptually similar to those in the first volume of our journal, Forum Kritische Archäologie Special Issue: What is a Critical Archaeology? This time, too, we sent authors a set of questions that we asked them to reflect upon in short essays.Anlässlich des 10-jährigen Bestehens des Forum Kritische Archäologie im Jahr 2022 haben wir im Herausgeber* innenkollektiv darüber nachgedacht, was mit dem Forum bisher erreicht wurde und was wir uns ursprünglich für diese Zeitschrift vorgestellt hatten. Während wir die Anzahl der kritischen Beiträge, die in den letzten 10 Jahren in unserer Zeitschrift veröffentlicht wurden, für ermutigend und in vielerlei Hinsicht innovativ halten, haben wir das Gefühl, dass es in einer Hinsicht noch viel zu tun gibt: die kritische Diskussion in der deutschen Archäologie selbst voranzutreiben. Die deutsche Wissenschaft entwickelt ihre Diskurse nach wie vor weitgehend im Rahmen kulturhistorischer Denkansätze, und die universitäre Lehre integriert nur langsam theoretisch fundierte oder kritischere Perspektiven. Wir haben uns daher gefragt, wie die Entwicklung solcher Ansätze in der deutschsprachigen Archäologie unterstützt werden kann, und uns entschieden, Kolleg*innen – internationale wie deutsche – zu bitten, über politische Formen der Archäologie zu schreiben, insbesondere über solche die als aktivistisch verstanden werden können. Die folgenden Beiträge ähneln konzeptionell denen im ersten Band unserer Zeitschrift (Forum Kritische Archäologie 1/Themenheft: Was ist eine kritische Archäologie?). Auch dieses Mal haben wir den Autor*innen eine Reihe von Fragen gestellt und sie gebeten, diese in kurzen Essays zu reflektieren

Empowerment durch wen und für wen?

In our concluding commentary on this theme issue, we would like to take a step back and address some questions about activism in general and the values we attach to it.In unserem abschließenden Kommentar zu diesem FKA-Themenheft möchten wir einen Schritt zurücktreten und einige Fragen zum Aktivismus im Allgemeinen und zu den Werten, die wir ihm beimessen, ansprechen