2,087 research outputs found
Taking historical chemistry to the bench: A new perspective for modern chemists through the re-creation and analysis of 19th-century Scottish Turkey red dyed textiles
Authenticating Turkey Red Textiles through Material Investigations by FTIR and UHPLC
Nineteenth-century Turkey red, a cotton textile
dyed by a peculiar and unique process, is found
in many collections around the world. It was
known for its bright colour and remarkable fastness
to light exposure and washing. Light fading
is a significant concern in the display of historical
textiles, and understanding more about the
properties of these objects may increase the
accessibility of collections. This research explored
the identification of historical Turkey red
through non-invasive Fourier transform infrared
(FTIR) spectroscopy to detect the presence of
oil â a necessary step in the process â on the
fibres. Around 1869, Turkey red dyers began to
transition from using madder and garancine
to synthetic alizarin, which was investigated
through ultra-high-performance liquid chromatography
(UHPLC). The chemical profiles of
19th-century samples and references of known
dye source were used to predict whether Turkey
red of unknown date was dyed with natural or
synthetic dye
A review of vibration problems in power station boiler feed pumps
Boiler feed pump reliability and availability is recognized as important to the overall efficiency of power generation. Vibration monitoring is often used as a part of planned maintenance. This paper reviews a number of different types of boiler feed pump vibration problems describing some methods of solution in the process. It is hoped that this review may assist both designers and users faced with similar problems
Fundamental reassessment of the taxonomy of five Normapolles pollen genera
National audienceDiagnoses of the Normapolles pollen genera Hungaropollis,Krutzschipollis, Longanulipollis, Oculopollis and Trudopollis and56 of their species are emended and many specimens illustrated inorder to provide a basis for more successful and consistent identificationthan has been possible hitherto. These taxa were recoveredfrom palynological preparations of selected samples from Late Cretaceousdeposits in Europe, southern Sweden and eastern USA.As indicated on an accompanying range chart the majority are encounteredin Santonian and/or Campanian deposits. Eleven of thespecies described have been transferred from other genera and aretherefore in new combinations, namely: Hungaropollis granulatus(Kedves et Herngreen), Longanulipollis coronatiformis (GĂłczĂĄnet Siegl-Farkas), L. orbicularis (GĂłczĂĄn), L. ornatus (Kedves etDiniz), L. parvoculus (GĂłczĂĄn), L. skarbyae (Kedves et Diniz),Oculopollis artifex (Weyland et Krieger), O. rector (Pflug), O.triceps (Skarby), Trudopollis cuneolis (GĂłczĂĄn et Siegl-Farkas),and T. spinulosus (Skarby). Six are new: Hungaropollis pinguis,Krutzschipollis cucullus, K. immanis, Longanulipollis amabilis, L.lobus and Oculopollis viriosus. Thirteen genera are regarded assynonyms of Hungaropollis (Aveiropollenites and Romeinipollenites),Longanulipollis (Coronatipollis, Intercalaripollis, Portaepollenitesand Verruoculopollis), Oculopollis (Druggipollenites, Pseudoculopollisand Semioculopollis) and Trudopollis (Cuneipollis,Felderipollenites, Hofkeripollenites and Kriegeripollenites) respectively.As a result of some of these nomenclatural changes 14 otherspecies are in new generic combinations but are not otherwise considered.Seven morphotypes are identified in open nomenclatureand four placed in comparison
Evaluation of chicory seeds maturity by chlorophyll fluorescence imaging
Chicory (Cichorium intybus L.) seed production includes sorting to remove foreign materials
and non-viable seeds. A machine vision system was developed to monitor the fluorescence
in order to detect the immature chicory seeds. It comprised a monochromatic light source,
a highpass filter and a monochromatic CCD camera sensitive to red and infrared. With this
device, blue light reflected by the seeds was blocked whilst red fluorescence was measured
by the camera. A segmentation algorithm was designed to estimate separately the fluorescence
intensities of the pappus, a crown of scales, and the main body of the pericarp.
Experiments were carried out on five clones of cross-pollinated chicory plants used for
seed production. Two hundred flower heads were labelled at flowering and harvested at
different times during the maturation process expressed in âdays after floweringâ (DAF).
Germination tests were performed according to the recommendations of the International
Seed Testing Association to measure the germination percentage (GP) and the germination
rate (GR), an indicator of seed vigour. Seed chlorophyll content diminished during maturation
following a different logistic trend for the pappus and the pericarp. The GP increased
from 18 DAF to reach its maximum value at 21 DAF, but the GR remained low until 30 DAF
and increased afterwards. The potential of chlorophyll fluorescence to be used as an
indicator of chicory seed vigour was the greatest between 21 and 36 DAF
Synthesis of 3,3-disubstituted heterocycles by Pd-catalyzed arylallylation of unactivated alkenes
Finding new methods of carbonâcarbon bond formation is a key goal in expanding current
methodology for heterocycle formation. Because of their inherently non-planar shape, new methods of
forming sp3-rich scaffolds are of particular importance. While there are methods for combining
heterocyclisation and formation of new sp3âsp3 carbonâcarbon bonds, these form the carbonâ
heteroatom bond rather than a carbonâcarbon bond of the heterocycle. Here we show a new alkene
arylallylation reaction that generates a heterocycle with concomitant formation of two new carbonâ
carbon bonds. Furthermore, we demonstrate that this process occurs through an isohypsic (redox
neutral) mechanism. Overall, this carboallylation reaction gives a new route to the synthesis of 3,3-
disubstituted heterocycles
Phonon-like hydrogen-bond modes in protic ionic liquids
Gigahertz- to terahertz-frequency infrared and Raman spectra contain a wealth of information concerning the structure, intermolecular forces, and dynamics of ionic liquids. However, these spectra generally have a large number of contributions ranging from slow diffusional modes to underdamped librations and intramolecular vibrational modes. This makes it difficult to isolate effects such as the role of Coulombic and hydrogen-bonding interactions. We have applied far-infrared and ultrafast optical Kerr effect spectroscopies on carefully selected ions with a greater or lesser degree of symmetry in order to isolate spectral signals of interest. This has allowed us to demonstrate the presence of longitudinal and transverse optical phonon modes and a great similarity of alkylammonium-based protic ionic liquids to liquid water. The data show that such phonon modes will be present in all ionic liquids, requiring a reinterpretation of their spectra
Re-examination of the palynological content of the Lower Cretaceous deposits of Angeac, Charente, south-west France::Age, palaeoenvironment and taxonomic determinations
International audienceFurther to the work published by NĂ©raudeau et al. six years ago, palynological matter recovered from the lignitic bone bed of Angeac in Charente (south-west France) has been re-examined in order to provide more evidence of its age, the previous HauterivianâBarremian interpretation being regarded as controversial. The samples come from four sedimentological units, An2âAn5, which together yielded an assemblage of 34 species, taxonomically dominated by palaeoecologically significant lygodiaceous verrucate spores, including eight species attributable to the genus Concavissimisporites and three species of Trilobosporites. A few bisaccate pollen grains, including Vitreisporites pallidus, have been recovered, but the gymnospermous pollen spectrum is clearly dominated by the cheirolepidiaceous genus Classopollis, its abundance diminishing progressively upwards from units An4 to An2. The great abundance and diversity of verrucate forms, along with the presence of other spores typical of Lower Cretaceous deposits, such as Aequitriradites verrucosus, and the scarcity of specimens referable to Cicatricosisporites, render this assemblage most similar to those of the Hastings Group of southern England, and the BĂŒckeberg Formation in north-western Germany. The time of deposition is, therefore, more likely to have been BerriasianâValanginian rather than HauterivianâBarremian, as previously stated. The associated small assemblage of megaspores is consistent with this determination. Except for Trilobosporites and Concavissimisporites, the use of several other genera commonly applied to Mesozoic verrucate spores, such as Converrucosisporites and Impardecispora, is considered unnecessary. To support this assertion, a Principal Components Analysis has been carried out on 120 verrucate spores from sedimentological units An2â4, taking into account ten morphological variables. The results show that specimens attributable to Trilobosporites are well be separated from the main cluster, which corresponds to Concavissimisporites, underlining the futility of using more than two genera for the species concerned
Jumping into the 20th century before it is too late: is laboratory robotics still in its infancy?
Successful management of laboratory robotic automation programmes
in the environment of research and drug discovery within
the pharmaceutical industry may perhaps be best compared to a chef
preparing the perfect hollandaise sauce. All the ingredients must be
available at the same time and be of highest quality for the right
price. However, if components are not added in the right quantities
and in the proper order, no amount of whipping together by the
product champion will create the best product. In the past,
managerial scepticism surrounding useful implementation of cost-effective,
high-throughput robotic systems often placed these
âmodern toysâ at low priorities for research development laboratories.
Management now recognizes the unique contributions of
robotics in the research environment. Although the scientific director
must still play the role of product champion, new questions are
being proposed and new commitments are being made to bring the
potential of robotic automation to every laboratory where repetitive
functions can benefit from new applications. Research laboratory
directors have become both the key ingredient, as well as the rate-limiting
determinant in the development of new applications.
Having fulfilled the promise of robotic automation to release
talented personnel, the challenge now is for the âend usersâ, the bench
scientists, to be provided with opportunities to invest the time and
effort required for future applications and new career functions
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