106 research outputs found
Spot Landing: Determining the Light and Solar Properties of Fritted and Coated Glass
The use of ceramic fritted architectural glazing is becoming increasingly popular. âFritted glassâ, which is also known as âenamelled glassâ, is defined as glass with a surface covering made of glass frit[1] that is applied by a printing method and fused to the glass substrate at elevated temperatures. The enamel coating may be continuous or consist of a discontinuous pattern such as spots or stripes. Functional thin-film coatings on glass have been used in standard glazing units for many years to improve thermal insulation or for solar control. Specification of light and solar properties for these standard glazing types is well-defined and can be calculated on the basis of the algorithms specified in EN 410:2011 or ISO 9050:2003. This is not the case for glazing that incorporates fritted glass, alone or in combination with functional thin-film coatings. The paper initially describes the different printing options for fritted glass and the fundamental principles of functional thin-film coatings. When glass surfaces are coated with glass frit, it is essential to note that the light-scattering coatings transmit and reflect incident radiation not only directly but also diffusely. The same applies when functional thin-film coatings are combined with frit coatings. Suitable measurement methods to collect the scattered radiation, measured transmittance and reflectance spectra, and the calculation of light and solar properties on the basis of the EN 410:2011 standard are presented. At the same time, the limits of this standard and the need for its extension are demonstrated.
[1] Frit: a durable mixture of glass and ceramic particles, which may act as pigments
Thermally Curved Glass - Research and Standardisation of the Four-Point Bending Test
Research has shown that the general approach to determine the bending strength of thermally curved glass with the aid of the four-point bending test for flat glass according to EN 1288-3 is applicable. At the moment, however, there is no statutory method available for directly extrapolating the breaking strain from the breaking load without the use of expensive strain gauges. Such a method is developed by means of an experimental and numerical study in a research project between the Bundesverband Flachglas e.V. (Federal Flat Glass Association) and the Fachverband Konstruktiver Glasbau e.V. (Professional Association Structural Glass Constructions), the Institute of Building Construction at the Technische UniversitĂ€t Dresden and four glass bending specialists. Moreover, it will provide the basis for testing cylindrically curved glass of any bending radius. The project partners have already submitted a proposal for a new standard to the Deutsches Institut fĂŒr Normung e.V. (German Institute for Standardisation). The paper gives the theoretical background for determining the strength of flat glass according to EN 1288â3 and quantifies the additional effects for the testing of thermally curved glass. Furthermore, the testing method of the executed experimental study on thermally curved glass is described. The range of parameters for the tested specimens included the glass thickness from 3 mm to 12 mm and the bending radii from 400 mm to 2000 mm. We recorded the strain at selected points at the tensioned side and the input force for each specimen. The measured relation between strain and load validates a numerical model, which is able to depict the actual two-dimensional stress distribution for thermally curved glass and includes non-linear aspects. The model allows for the determination of correction factors. With those, the bending strength of thermally curved glass can be calculated by measuring merely the input force during the four-point bending tests. The correction factors are summarised in charts depending on the radius and the thickness of the glass sample
Thermal Glass Stress Analysis â Design Considerations
The use of glass in windows and curtain walls, in residential as well as in high-rise buildings, is something that requires great care in design and execution. Apart from complying with typical structural engineering practices and ensuring, for example, that the glass thickness is sufficient to withstand wind loads, impact loads etc. it is necessary always also to consider the thermal-stress resistance of the glass employed as well as the temperature distribution across glass and façade components. This topic is not new as it began to be analysed with the emergence of the first body tinted basic glass types. All the analysis done today is based on a linear approach and a more or less simplified algorithm. But modern constructions make it necessary to recognize special details and to acquire a more detailed view of the construction and use of such windows and curtain walls. Glass manufacturers can assist in this by helping to analyse the thermal stress characteristics but also the temperature distribution in different constructions. It is necessary here also to evaluate the different boundary conditions, which vary from location to location. The paper will begin by describing the basic methods for analysing the thermal-stress resistance of glazing units. But it will then go on to show the influence of the boundary conditions on the final result. The paper will also show the effect of a detailed 2D FE analysis in specifically analysing critical locations in curtain walls, such as shadow boxes or spandrel areas
final results of the observational EXPLAIN-FXS study
Background As data on the phenotype, characteristics and management of
patients with Fragile X Syndrome (FXS) are limited, we aimed to collect such
data in Germany in experienced centres involved in the treatment of such
patients. Methods EXPLAIN-FXS is a prospective observational (non-
interventional) study (registry) performed between April 2013 and January 2016
at 18 sites in Germany. Requirements for patient participation included
confirmed diagnosis of FXS by genetic testing (>200 CGG repeats) and written
informed consent. Patients were followed for up to 2 years. Results Seventy-
five patients (84.0 % males, mean age 16.7â±â14.5 years, ranging from 2 - 82
years) were analysed. The mean 6-item score, determined according to Giangreco
(J Pediatr 129:611-614, 1996), was 6.9â±â2.5 points. At least one neurological
finding each was noted in 53 patients (69.7 %). Specifically, ataxia was noted
in 5 patients (6.6 %), lack of fine motor skills in 40 patients, (52.6 %),
muscle tonus disorder in 4 patients (5.3 %), and other neurological disorders
in 39 patients (51.3 %). Spasticity was not noted in any patient. Seizures
were reported in 6 patients (8.1 %), anxiety disorders in 22 patients (30.1
%), depression in 7 patients (9.6 %), ADHD/ADD in 36 patients (49.3 %),
impairment of social behavior in 39 patients (53.4 %), and other comorbidities
in 23 patients (31.5 %). The mean Aberrant Behaviour Checklist Community
Edition (ABC-C) score on behavioral symptoms, obtained in 71 patients at first
documentation, was 48.4â±â27.8 (median 45.0, range 5-115). The mean visual
analogue scale (VAS) score, obtained in 59 patients at first documentation,
was 84.9â±â14.6 points (median 90; range 50 â 100). Conclusions This report
describes the largest cohort of patients with FXS in Europe. The reported
observations indicate a substantial burden of disease for patients and their
caregivers. Based on these observations, an early expert psychiatric diagnosis
is recommended for suspected FXS patients. Further recommendations include
multimodal and multi-professional management that is tailored to the
individual patientâs needs. Trial registration The ClinTrials.gov identifier
is NCT01711606. Registered on 18 October 2012
Diâ and TetracyanoâSubstituted PyreneâFused Pyrazaacenes: Aggregation in the Solid State
Means to stream: Five di- and tetracyano-substituted pyrene-fused pyrazaacenes were synthesized and studied as potential electron acceptors in the solid state. Single crystals of all compounds were grown, and the crystal packing was studied by XRD and DFT calculations of transfer integrals and reorganization energies with a view to their possible use as n-type semiconductors.
Five di- and tetracyano-substituted pyrene-fused pyrazaacenes were synthesized and studied as potential electron acceptors in the solid state. Single crystals of all compounds were grown and the crystal packing studied by DFT calculations (transfer integrals and reorganization energies) to get insight into possible use for semiconducting charge transport
HostâGuest Chemistry of Truncated Tetrahedral Imine Cages with Ammonium Ions
Three shape-persistent [4+4] imine cages with truncated tetrahedral geometry with different window sizes were studied as hosts for the encapsulation of tetra-n-alkylammonium salts of various bulkiness. In various solvents the cages behave differently. For instance, in dichloromethane the cage with smallest window size takes up NEtt but not NMet, which is in contrast to the two cages with larger windows hosting both ions. To find out the reason for this, kinetic experiments were carried out to determine the velocity of uptake but also to deduce the activation barriers for these processes. To support the experimental results, calculations for the guest uptakes have been performed by molecular mechanicsâ simulations. Finally, the complexation of pharmaceutical interested compounds, such as acetylcholine, muscarine or denatonium have been determined by NMR experiments
Quinoxalinophenanthrophenazine Based Cruciforms
Quinoxalinophenanthrophenazines (QPPs) and related structures are an emerging class of stable fused N-heteropolycyclic aromatics. By vertical attachment of aromatic substituents at the pyrene core, cruciform QPPs are accessible, which open new opportunities to adjust HOMO and LUMO levels of the QPPs nearly independent from each other.
A series of cruciform aryl-substituted quinoxalinophenanthrophenazine derivatives (QPPs) was synthesized through Suzuki-Miyaura cross-coupling of a 2,7-diborylated pyrene tetraketal building block. The QPPs were analyzed for their optoelectronic properties by absorption and emission spectroscopy, cyclic voltammetry and quantum-chemical calculations. The solid-state packing was investigated as well and evaluated for its charge transport properties by calculated charge transfer integrals
Testing Galactic Magnetic Field Models using Near-Infrared Polarimetry
This work combines new observations of NIR starlight linear polarimetry with
previously simulated observations in order to constrain dynamo models of the
Galactic magnetic field. Polarimetric observations were obtained with the Mimir
instrument on the Perkins Telescope in Flagstaff, AZ, along a line of constant
Galactic longitude (\ell = 150\circ) with 17 pointings of the 10' \times 10'
field of view between -75\circ < b < 10\circ, with more frequent pointings
towards the Galactic midplane. A total of 10,962 stars were photometrically
measured and 1,116 had usable polarizations. The observed distribution of
polarization position angles with Galactic latitude and the cumulative
distribution function of the measured polarizations are compared to predicted
values. While the predictions lack the effects of turbulence and are therefore
idealized, this comparison allows significant rejection of A0-type magnetic
field models. S0 and disk-even halo-odd magnetic field geometries are also
rejected by the observations, but at lower significance. New predictions of
spiral-type, axisymmetric magnetic fields, when combined with these new NIR
observations, constrain the Galactic magnetic field spiral pitch angle to
-6\circ \pm 2\circ.Comment: 11 pages, 10 figures, Accepted for publication in Ap
Triptycene EndâCapped Benzothienobenzothiophene and Naphthothienobenzothiophene
Previously it was demonstrated that triptycene endâcapping can be used as a crystal engineering strategy to direct the packing of quinoxalinophenanthrophenazines (QPPs) towards cofacially stacked Ï dimers with large molecular overlap resulting in high charge transfer integrals. Remarkably, this packing motif was formed under different crystallization conditions and with a variety of derivatives bearing additional functional groups or aromatic substituents. Benzothienobenzothiophene (BTBT) and its derivatives are known as some of the best performing compounds for organic fieldâeffect transistors. Here, the triptycene endâcapping concept is introduced to this class of compounds and polymorphic crystal structures are investigated to evaluate the potential of triptycene endâcaps as synthons for crystal engineering
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