Triggers for chemical product design: A systematic literature review

The product design project is a complex problem because objectives and constraints must be considered simultaneously, the sustainability context is highly relevant and specific, decision-making involves not only customer needs but also of other stakeholders, especially the organization in which the design project takes place. This work presents a systematic literature review of design methodologies for chemical products to identify how that problem has been addressed and which are the future challenges to be met. The review involved the analysis of 262 research papers and 336 patents, classified according to the chemical product type, the design phase studied, and whether they consider association with a business context. The study highlights the need for holistic product design methodologies applicable from the early design stages, covering the assessment of customer needs and the requirements of other stakeholders, as well as the business context where the design process is carried out.     

Influence of pulse current during Spark Plasma Sintering evidenced on reactive alumina-hematite powders

Spark Plasma Sintering (SPS) is increasingly used. The temperature and current are not independent parameters, making it difficult to separate the current intrinsic role from Joule heating. There is a debate on whether there are any specific SPS mechanisms. The influence of a key parameter, the (on:off) pulse pattern, is studied on the SPS of reactive α-Al_2−2xFe_2xO₃ (x = 0.02; 0.05; 0.07; 0.10) powders. Changing it modifies the current crest intensity and has a great influence on the materials microstructure. Comparisons with runs where the current is blocked and hot-pressing reveal three competing phenomena: formation of FeAl₂O₄, dominant in the core and not peculiar to SPS, formation of Fe, producing Fe-Al₂O₃ composite surface layers, and most notably electrical-field induced diffusion of Fe³⁺ ions towards the cathode, which could have far-ranging implications for the consolidation of ionic materials and the in situ reactive shaping of composites and multimaterials.     

Invited review: Disentangling residual feed intake—Insights and approaches to make it more fit for purpose in the modern context

Residual feed intake (RFI) is an increasingly used trait to analyze feed efficiency in livestock, and in some sectors such as dairy cattle, it is one of the most frequently used traits. Although the principle for calculating RFI is always the same (i.e., using the residual of a regression of intake on performance predictors), a wide range of models are found in the literature, with different predictors, different ways of considering intake, and more recently, different statistical approaches. Consequently, the results are not easily comparable from one study to another as they reflect different biological variabilities, and the relationship between the residual (i.e., RFI) and the underlying true efficiency also differs. In this review, the components of the RFI equation are explored with respect to the underlying biological processes. The aim of this decomposition is to provide a better understanding of which of the processes in this complex trait contribute significantly to the individual variability in efficiency. The intricacies associated with the residual term, as well as the energy sinks and the intake term, are broken down and discussed. Based on this exploration as well as on some recent literature, new forms of the RFI equation are proposed to better separate the efficiency terms from errors and inaccuracies. The review also considers the time period of measurement of RFI. This is a key consideration for the accuracy of the RFI estimation itself, and also for understanding the relationships between short-term efficiency, animal resilience, and long-term efficiency. As livestock production moves toward sustainable efficiency, these considerations are increasingly important to bring to bear in RFI estimations.     

Reconceptualizing chemical elements through the construction of the periodic system

Mendeleev was one of a dozen or more chemists who aimed to create a classification of elements in the mid‐19th century. Mendeleev distinguished himself among the discoverers of the periodic system in their priority disputes because he was the only one who bothered to provide a clear definition of the entities to be ordered. This paper will first outline the role of Mendeleev's conceptual distinction between “element” and “simple substance” in the process of constructing the periodic table. Symmetrically, it will emphasize how the periodic system reconfigured the notion of the element as a relational entity, defined by its relations with other elements, a notion stabilized by the invention of the concept of isotopes in the early 20th century.     

Development and validation of chemistry agnostic flow battery cost performance model and application to nonaqueous electrolyte systems

A chemistry agnostic cost performance model is described for a nonaqueous flow battery. The model predicts flow battery performance by estimating the active reaction zone thickness at each electrode as a function of current density, state of charge, and flow rate using measured data for electrode kinetics, electrolyte conductivity, and electrode‐specific surface area. Validation of the model is conducted using a 4 kW stack data at various current densities and flow rates. This model is used to estimate the performance of a nonaqueous flow battery with electrode and electrolyte properties used from the literature. The optimized cost for this system is estimated for various power and energy levels using component costs provided by vendors. The model allows optimization of design parameters such as electrode thickness, area, flow path design, and operating parameters such as power density, flow rate, and operating SOC range for various application duty cycles. A parametric analysis is done to identify components and electrode/electrolyte properties with the highest impact on system cost for various application durations. A pathway to 100$ kW h^?1 for the storage system is identified. Copyright © 2016 John Wiley & Sons, Ltd.     

N-Heterocyclic Carbene Iron Silyl Hydride Complexes

Reaction of N-heterocyclic carbene iron(0) tetracarbonyl complexes with hydrosilanes (triphenylsilane, methyldiphenylsilane and diphenylsilane) under UV irradiation (350 nm) afforded the octahedral N-heterocyclic carbene iron(II) silyl hydride complexes in yields up to 95 %, resulting from the oxidative addition of the hydrosilane. Eight iron silyl hydrides were obtained and characterized by NMR and X-ray diffraction analysis. Noticeably, the geometry of the iron-hydride complexes and the bent structures of the carbonyl ligands were rationalized by DFT calculations.     

An investigation of the object relations theory of depression.

The current study investigated a particular aspect shared by a number of theories of depression under the common heading of object relations theory (ORT), namely that depression is associated with a continuing pattern of poor attachment that is laid out in childhood and continues into adulthood. The study examined the relationship between attachment (both parental and peer) and depressive symptoms in young adults (N = 85) of Northern Ireland. Results provided support for the continuity of perceptions of attachment styles across the life span and revealed that perceptions of early attachment experiences, as well as continuing peer attachment styles, appeared to be predictive of current depressive symptoms. More specifically, the analyses revealed a statistically significant positive correlation between perceived quality of current peer attachment and symptoms of depression, as well as a statistically significant negative correlation between self-reported childhood maternal care and symptoms of depression. However, other self-reported measures of childhood attachment were not found to be significant predictors of depressive symptoms (i.e., paternal care, maternal overprotection, paternal overprotection). Taken together, the findings lend some support for this important element of a number of object relations theories, as they pertain to depression. Further empirical research is indicated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)