The relationship of molecular structure to mesomorphism in some aromatic esters of diphenols

Matter exists principally in three distinct states -crystalline solid, isotropic liquid, and gas. Individual units in both the liquid and gaseous state are more or less mobile, while in the crystalline solid state these units are held in the rigid, three dimensional configuration of a crystalline lattice. Consequently, the crystalline solid is regarded as the most highly ordered of the three states of matter. Heating a crystalline solid increases the thermal vibrations and the ordered arrangement begins to break down. The solid passes from the highly organized crystalline state to the disorganized isotropic liquid. In 1888, Friedrich Reinitzer discovered that, on melting cholesteryl benzoate, the solid collapsed to form a turbid liquid which, on further heating, gave the normal, transparent, isotropic liquid.1 This turbid liquid exhibited properties of both liquid and crystalline forms of matter; the substance was both birefringent (a property of crystals) and fluid. Although Reinitzer is credited with discovering the liquid crystalline phenomenon, Lehmann2 was first to suggest the name "liquid crystals", and to describe their properties. Later, Friedel3,4 proposed the term "mesomorphs" or "mesophases" for substances that were neither isotropic liquids nor crystalline solids. Since both terminologies are generally accepted, the terms liquid crystal and mesomorph, or liquid crystallinity and mesomorphism, will be used interchangeably throughout this thesis

Laboratory testing for wear performance of selected wood floor finishes

Eight wood floor finishes were applied to quarter-sawn, red oak flooring blocks and, along with a factory finished block, were tested under laboratory conditions to determine the degree of wear of each of the finishes. A loss in film thickness of the finish was considered wear. Test blocks included four replicates each of polyurethane, vinyl, epoxy, amino resin, lacquer, shellac, varnish, penetrating seal, and a prefinished specimen. Blocks were tested on the Simulated Human Wear Producing Machine consisting of a treadmill and cam-operated legs and feet developed by Dr. Henry Bowen and his engineering students of the Biological and Agricultural Engineering Department at North Carolina State University in Raleigh. A Zeiss Light-Section Microscope was used to measure the film thickness of finishes. Four measurements were recorded from predetermined locations and the mean computed for each test specimen of each finish before testing and during testing at one, two, four, five, six, and eight hour intervals. Blocks were rotated on the machine after each measurement period

Academic research into marketing: many publications, but little impact?

This article reviews some issues associated with the way in which academic research into marketing is evaluated by UK education authorities using their Research Excellence Framework (REF), in particular the impact component of the assessment. It discusses the extent to which research by marketing academics published in leading academic journals is relevant to the concerns of marketing management and how this relevance or lack of it may be reflected in the relative paucity of impact submissions in marketing. It considers the model of impact assessment used in the REF and how this differs from how marketing academics work in practice, giving three examples of significant impact that would not be acceptable under current rules. It concludes by suggesting that alternative models for impact should be investigated and suggests that using more practical models might result in better engagement of marketing academics with business, leading to greater relevance in teaching and employability of marketing graduates

Measurement of ϒ production in pp collisions at √s = 2.76 TeV

The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→μ+μ− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→μ+μ− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→μ+μ− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Study of the doubly charmed tetraquark T+cc

Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed