Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

Of Theory and Practice

Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz*,‡ †Division of Biology, Department of Chemistry and Materials Science, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States ‡Center for Bio/Molecular Science and Engineering Code 6900 and Division of Optical Sciences Code 5611, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States College of Science, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, California 95817, United States Sotera Defense Solutions, Crofton, Maryland 21114, United States

Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology.

The discovery of graphene and other two-dimensional (2D) materials together with recent advances in exfoliation techniques have set the foundations for the manufacturing of single layered sheets from any layered 3D material. The family of 2D materials encompasses a wide selection of compositions including almost all the elements of the periodic table. This derives into a rich variety of electronic properties including metals, semimetals, insulators and semiconductors with direct and indirect band gaps ranging from ultraviolet to infrared throughout the visible range. Thus, they have the potential to play a fundamental role in the future of nanoelectronics, optoelectronics and the assembly of novel ultrathin and flexible devices. We categorize the 2D materials according to their structure, composition and electronic properties. In this review we distinguish atomically thin materials (graphene, silicene, germanene, and their saturated forms; hexagonal boron nitride; silicon carbide), rare earth, semimetals, transition metal chalcogenides and halides, and finally synthetic organic 2D materials, exemplified by 2D covalent organic frameworks. Our exhaustive data collection presented in this Atlas demonstrates the large diversity of electronic properties, including band gaps and electron mobilities. The key points of modern computational approaches applied to 2D materials are presented with special emphasis to cover their range of application, peculiarities and pitfalls.

https://www.rsc.org/suppdata/cs/c4/c4cs00102h/c4cs00102h1.pdf

An atlas of two-dimensional materials

Fundamentals, present and future perspectives of electrocoagulation.

Acid Red 14 (AR14), commonly used as a textile dye, could be photocatalytically degraded using TiO 2 suspensions irradiated by a UV-C lamp (30 W). The experiments showed that TiO 2 and UV light had a negligible effect when they were used on their own. The semi-log plot of dye concentration versus time was linear, suggesting first order reaction ( K =1.41×10 −2  min −1 ). The effects of some parameters such as pH, the amount of TiO 2 and initial dye concentration were also examined. The photodegradation of AR14 was enhanced by the addition of proper amount of hydrogen peroxide, but it was inhibited by ethanol. From the inhibitive effect of ethanol it was deducted that hydroxyl radicals played a significant role in the photodegradation of dye, but a direct oxidation by positive holes was probably not negligible. Accordingly, it could be stated that the complete removal of color, after selecting optimal operational parameters could be achieved in a relatively short time, about 3.5 h.

Photocatalytic degradation of azo dye acid red 14 in water: investigation of the effect of operational parameters

https://www.jpcomplex.ir/Content/media/image/2013/08/773_orig.pdf

Electrocoagulation (EC)--science and applications.

A Fourier transform infrared spectroscopic investigation of the early hydration of Portland cement and the influence of sodium lignosulfonate

This paper presents a focused review of cement–superplasticizer interactions. It has been concluded from the survey of the literature that cement–superplasticizer interactions are generally preceded by the adsorption of superplasticizers on the hydrating cement particles. However, the mechanisms of such adsorptive interactions have not been adequately addressed experimentally or discussed in the literature. The reason for this appears to be the lack of a conceptual model that can delineate the results to date and project needed experiments. A charge-controlled-reaction mechanism model involving Ca2+ ions from initial hydration is proposed to explain the adsorption characteristics of superplasticizers and other organic additives and their effects. The calcium ions released by hydration form a bilayer immediately upon contact of water with the cement, which is followed by adsorption of superplasticizer anions on the Ca2+ ion side of the bilayer. The interfacial structures and their influence on electrical c...

A review of cement–superplasticizer interactions and their models

The growth and geometric structure of ultrathin zinc oxide films on Pd(111) has been studied by scanning tunneling microscopy, low-energy electron diffraction, and density functional theory calculations. For sub-monolayer coverages, depending on the oxygen pressure, two well-ordered zinc oxide phases with (4 × 4) and (6 × 6) coincidence structures form, which are attributed to H-terminated Zn6O5 and graphite-like Zn6O6 layers, respectively. The (6 × 6) phase exhibits a pronounced oxygen pressure dependence: at low p(O2) a well-ordered (6 × 6) two-dimensional array of O vacancies develops, yielding a layer with a formal Zn25O24 stoichiometry, while at high p(O2) the Zn6O6 monolayer transforms into bilayer islands. For oxide coverages up to 4 monolayers the graphite-like Zn6O6 structure is thermodynamically the most stable phase over a large range of oxygen chemical potentials, before it converges to the bulk-type wurtzite structure. Under oxygen-poor conditions a compressed overlayer of Zn adatoms can be s...

Growth and Surface Structure of Zinc Oxide Layers on a Pd(111) Surface

Ultraviolet and x-ray photoelectron spectroscopies were used to study electronic properties of interfaces between Au substrates and a number of organic semiconductors (small molecules and polymers). Au surface work function (ϕ) values before organic deposition were ∼4.7eV (exposed to air), ∼5.2eV (atomically clean), and ∼5.5eV (UV∕ozone treated). The high ϕ obtained for UV∕O3 treated Au was due to Au oxide formation and surface-adsorbed carbon and oxygen species. Au surface morphology remained essentially unchanged by UV∕ozone exposure, as observed by atomic force microscopy. Hole injection barriers (HIBs) at interfaces between UV∕ozone treated Au and the organic semiconductors were systematically lower than those for untreated Au (both atomically clean and air exposed). Reductions in HIB of up to 1.4eV (for p-sexiphenyl) were achieved. In addition, good long-term stability of reduced HIBs of such interfaces was observed for air storage of up to several days.

Robert Schennach

Papers

Electrocoagulation (EC)--science and applications.

A Fourier transform infrared spectroscopic investigation of the early hydration of Portland cement and the influence of sodium lignosulfonate

A review of cement–superplasticizer interactions and their models

Growth and Surface Structure of Zinc Oxide Layers on a Pd(111) Surface

UV∕ozone treated Au for air-stable, low hole injection barrier electrodes in organic electronics