Designing as reflective conversation with the materials of a design situation

What are the prospects for applying the methods of Artificial Intelligence to architectural designers' knowing-in-action? David Marr (Marr, 1982) has advanced the idea of a computational theory of vision, which requires defining the information processing tasks carried out in vision. I ask, by analogy: what are the information processing tasks carried out in design? In order to answer this question, I propose, one ought to study design phenomenology. I illustrate several such studies, based on observations of a design studio, the performance of a design exercise, and the playing of a design game. In order to simulate the transactions with a design situation illustrated in these studies, the computer would have to carry out processes that begin prior to the presentation of what are normally defined as “design inputs.” Such processes involve the construction of “design worlds,” and they include: the simplest unit of design experimentation, the designer's seeing-moving-seeing; constructing figures from marks on a page; appreciating design qualities; setting design intentions and problems; recognizing the unintended consequences of move experiments; storing and deploying prototypes; and communicating across divergent design worlds. I conclude that the practitioners of Artificial Intelligence in design would do better to aim at producing design assistants rather than knowledge systems phenomenologically equivalent to those of designers.     

Bio‐Derived Polymers for Sustainable Lithium‐Ion Batteries

Biologically derived organic molecules are a cost‐effective and environmentally benign alternative to the widely used metal‐based electrodes employed in current energy storage technologies. Here, the first bio‐derived pendant polymer cathode for lithium‐ion batteries is reported. The redox moiety is flavin and is derived from riboflavin (vitamin B₂). A semi‐synthetic methodology is used to prepare the pendant polymer, which is composed of a poly(norbornene) backbone and pendant flavin units. This semi‐synthetic approach reduces the number of chemical transformations required to form this new functional material. Lithium‐ion batteries incorporating this polymer have a 125 mAh g^?1 capacity and an ≈2.5 V operating potential. It is found that charge transport is greatly improved by forming hierarchical structures of the polymer with carbon black, and new insight into electrode degradation mechanisms is provided which should be applicable to polymer electrodes in general. This work provides a foundation for the use of bio‐derived pendant polymers in sustainable, high‐performance lithium‐ion batteries.     

International comparison of HV impulse measuring systems

The authors studied the agreement between laboratory measurements of full and front-chopped lightning impulses at four national laboratories. First, some general information on how standards are maintained and disseminated is presented together with a brief review of the requirements for HV impulse measurements. Then, the comparative measurements made in the four national laboratories are presented and the relative differences are reported. Comparative measurements can be made for full standard lightning impulses to within 1% for crest voltages and to within 5% for front times. These uncertainties may be adequate to allow the calibration of industrial measuring systems to within 3% for crest values and 10% for front times, as is required by the relevant standards, provided the systematic errors of the reference system are sufficiently small     

Myoclonic epilepsy with ragged-red fibers (MERRF): an immunohistochemical study of the brain

Myoclonic epilepsy with ragged-red fibers (MERRF) is a maternally inherited disorder of oxidative phosphorylation due to specific point mutations within the mitochondrial tRNA(Lys) gene. Mitochondrial dysfunction in the central nervous system (CNS) of patients with MERRF accounts for the neurological manifestations of the disease. Antibodies against subunits of complex I, III, IV and V of the respiratory chain were used to study the expression of these proteins in the frontal cortex, cerebellum and medulla from an autoptic case of MERRF. We found a selective decreased expression of subunit II of cytochrome c oxidase (COX-II) in these regions. Immunohistochemical abnormalities were more widespread than the lesions described by traditional histopathological techniques and made possible an attempt of explanation for the neurological symptoms of the patient.     

Apparent mtDNA heteroplasmy in Alzheimer's disease patients and in normals due to PCR amplification of nucleus-embedded mtDNA pseudogenes

In an unprecedented finding, Davis et al. [Davis, R. E., Miller, S., Herrnstadt, C., Ghosh, S. S., Fahy, E., Shinobu, L. A., Galasko, D., Thal, L. J., Beal, M. F., Howell, N. & Parker, W. D., Jr. (1997) Proc. Natl. Acad. Sci. USA 94, 4526-4531] used an unusual DNA isolation method to show that healthy adults harbor a specific population of mutated mitochondrial cytochrome c oxidase (COX) genes that coexist with normal mtDNAs. They reported that this heteroplasmic population was present at a level of 10-15% in the blood of normal individuals and at a significantly higher level (20-30%) in patients with sporadic Alzheimer's disease. We provide compelling evidence that the DNA isolation method employed resulted in the coamplification of authentic mtDNA-encoded COX genes together with highly similar COX-like sequences embedded in nuclear DNA ("mtDNA pseudogenes"). We conclude that the observed heteroplasmy is an artifact.     

Soft Wearable Systems for Colorimetric and Electrochemical Analysis of Biofluids

Wearable monitoring systems provide valuable insights about the state of wellness, performance, and progression of diseases. Although conventional wearable systems have been effective in measuring a few key biophysical markers, they offer limited insights into biochemical activity and are otherwise cumbersome in ambulatory modes of use, relying on wired connections, mechanical straps, and bulky electronics. Recent advances in skin‐interfaced microfluidics, stretchable/flexible electronics, and mechanics have created new wearable systems with capabilities in real‐time, noninvasive analysis of sweat biochemistry in combination with biophysical metrics. Here, the latest technologies in multifunctional sweat sensing systems are presented with a focus on novel microfluidic designs, fully‐integrated wireless electrochemical sensors, and hybrid biochemical/biophysical sensing capabilities, creating real‐time physiological insights.     

Salt effect of lithium bromide on the solution polymerization of acrylonitrile

Abstract

In this paper, the salt effect of lithium bromide (LiBr) on the dimethyl formamid (DMF) solution polymerization of acrylonitrile was studied. From the experimental data, we proposed a possible mechanism and derived its rate expression to determine the kinetic parameters for this system. The results show that the values of k_v/k_tr (1.984～79.365) and k_t/k² _tr (3.311×l0²～3.156×l0⁵ sec·mole/1) of the DMF‐LiBr solution polymerization of acrylonitrile are larger than those of the DMF‐LiCl solution polymerization of acrylonitrile shown by Bamford and others. These results can be explained by the basicity of salt and the dissociation of polyacrylonitrile in the DMF‐LiBr solution.     

Chemically Addressable Perovskite Nanocrystals for Light‐Emitting Applications

Whereas organic–inorganic hybrid perovskite nanocrystals (PNCs) have remarkable potential in the development of optoelectronic materials, their relatively poor chemical and colloidal stability undermines their performance in optoelectronic devices. Herein, this issue is addressed by passivating PNCs with a class of chemically addressable ligands. The robust ligands effectively protect the PNC surfaces, enhance PNC solution processability, and can be chemically addressed by thermally induced crosslinking or radical‐induced polymerization. This thin polymer shield further enhances the photoluminescence quantum yields by removing surface trap states. Crosslinked methylammonium lead bromide (MAPbBr₃) PNCs are applied as active materials to build light‐emitting diodes that have low turn‐on voltages and achieve a record luminance of over 7000 cd m^?2, around threefold better than previous reported MA‐based PNC devices. These results indicate the great potential of this ligand passivation approach for long lifespan, highly efficient PNC light emitters.     

Risk assessment based on weak information using belief functions: a case study in water treatment

Whereas probability theory has been very successful as a conceptual framework for risk analysis in many areas where a lot of experimental data and expert knowledge are available, it presents certain limitations in applications where only weak information can be obtained. One such application investigated in this paper is water treatment, a domain in which key information such as input water characteristics and failure rates of various chemical processes is often lacking. An approach to handle such problems is proposed, based on the Dempster-Shafer theory of belief functions. Belief functions are used to describe expert knowledge of treatment process efficiency, failure rates, and latency times, as well as statistical data regarding input water quality. Evidential reasoning provides mechanisms to combine this information and assess the plausibility of various noncompliance scenarios. This methodology is shown to boil down to the probabilistic one where data of sufficient quality are available. This case study shows that belief function theory may be considered as a valuable framework for risk analysis studies in ill-structured or poorly informed application domains.