315 research outputs found
Low-coherence interferometric measurement of the spectral dependence of the light field backscattered by optical interfaces
In this paper, we show how the combined use of low coherence interferometry,
balanced detection and data processing comparable to that used in Fourier
transform spectrometry allows us to characterize with ultimate resolutions
(sub-ppm in level, 0.2 nm in wavelength and 5 mdeg in angle) the
retro-reflection and retro-scattering response of both sides of a 2 mm thick
silica wafer
Open architecture control system for a modular reconfigurable machine tool.
M.Sc.Eng. University of KwaZulu-Natal, Durban 2013.The present day manufacturing environment has forced manufacturing systems to be flexible and
adaptable to be able to match the product demands and frequent introduction of new products and
technologies. This research forms part of a greater research initiative that looks at the development of
the reconfigurable manufacturing paradigm. Previous research has shown that the lack of
development of a Modular Reconfigurable Manufacturing Tools (MRMT) and Open Architecture
Control System (OACS) is currently a key limiting factor to the establishment of Reconfigurable
Manufacturing Systems (RMS), which has been the primary motivation for this research.
Open Architecture (OA) systems aim to bring the ideas of RMS to control systems for machining
systems. An OA system incorporates vendor neutrality, portability, extendibility, scalability and
modularity. The research has proposed, designed and developed a novel solution that incorporates
these core principles allowing the system to be flexible in mechanical and control architectures. In
doing so, the system can be reconfigured at any time to match the specific manufacturing functionality
required at that time thereby prolonging the lifecycle of the machine via multiple reconfigurations
over time, in addition to decreasing the cost of system modifications due to a well-defined modular
system. The reconfiguration and machining variance is achieved by the introduction of mechanical and
control modules that extend the Degrees of Freedom (DOF’s) available to the system.
The OACS has been developed as a modular solution that links closely to the existing mechanical
modularity on the RMT to maximize the reconfigurability of the system. The aim was to create a one to
one link between mechanical and electronic hardware and the software system. This has been
achieved by the addition of microcontroller based distributed modules which acts as the interface
between the electro-mechanical machine axes via hardwired signals and the host PC via the CAN bus
communication interface.
The distributed modules have been developed on different microcontrollers, which have successfully
demonstrated the openness and customizability of the system. On the host PC, the user is presented
with a GUI that allows the user to configure the control system based on the MRMT physical
configuration. The underlying software algorithms such as, text Interpretation, linear interpolation, PID
or PI controllers and determination of kinematic viability are part of the OACS and are used at run time
for machine operation.
The machining and control performance of the system is evaluated on the previously developed
MRMT. The performance evaluation also covers the analysis of the reconfigurability and scalability of
the system. The research is concluded with a presentation based on conclusions drawn from the
research covering the challenges, limitations and problems that OA and RMS can face before MRMT
become readily available for industry
Audio-visual synchrony and spatial attention enhance processing of dynamic visual stimulation independently and in parallel: A frequency-tagging study
The neural processing of a visual stimulus can be facilitated by attending to its position or by a co-occurring auditory tone. Using frequency-tagging, we investigated whether facilitation by spatial attention and audio-visual synchrony rely on similar neural processes. Participants attended to one of two flickering Gabor patches (14.17 and 17 Hz) located in opposite lower visual fields. Gabor patches further “pulsed” (i.e. showed smooth spatial frequency variations) at distinct rates (3.14 and 3.63 Hz). Frequency-modulating an auditory stimulus at the pulse-rate of one of the visual stimuli established audio-visual synchrony. Flicker and pulsed stimulation elicited stimulus-locked rhythmic electrophysiological brain responses that allowed tracking the neural processing of simultaneously presented Gabor patches. These steady-state responses (SSRs) were quantified in the spectral domain to examine visual stimulus processing under conditions of synchronous vs. asynchronous tone presentation and when respective stimulus positions were attended vs. unattended. Strikingly, unique patterns of effects on pulse- and flicker driven SSRs indicated that spatial attention and audiovisual synchrony facilitated early visual processing in parallel and via different cortical processes. We found attention effects to resemble the classical top-down gain effect facilitating both, flicker and pulse-driven SSRs. Audio-visual synchrony, in turn, only amplified synchrony-producing stimulus aspects (i.e. pulse-driven SSRs) possibly highlighting the role of temporally co-occurring sights and sounds in bottom-up multisensory integration
Thermal invisibility based on scattering cancellation and mantle cloaking
Article accompagné d'un corrigendum : 10.1038/srep19321International audienceWe theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal invisibility may open new vistas in hiding hot spots in infrared thermography, military furtivity, and electronics heating reduction
Antibodies against phosphorylcholine in hospitalized versus non‑hospitalized obese subjects
Obesity associates with reduced life expectancy, type 2 diabetes, hypertension and cardiovascular disease, and is characterized by chronic inflammation. Phosphorylcholine (PC) is an epitope on oxidized low-density lipoprotein, dead cells and some microorganisms. Antibodies against PC (anti-PC) have anti-inflammatory properties. Here, we explored the role of anti-PC in hospitalized versus non-hospitalized obese. One-hundred-and-twenty-eight obese (BMI ≥ 30 kg/m2) individuals (59.8 (± 5.5) years, 53.9% women) from the Malmö Diet and Cancer Cardiovascular Cohort were examined and IgM, IgG1 and IgG2 anti-PC were analyzed by ELISA. Individuals with at least one recorded history of hospitalization prior to study baseline were considered hospitalized obese (HO). Associations between IgM, IgG1 and IgG2 anti-PC and HO (n = 32)/non-hospitalized obese (NHO) (n = 96), but also with metabolic syndrome and diabetes were analysed using logistic regressions. Both IgM and IgG1 anti-PC were inversely associated with HO, also after controlling for age and sex. When further adjusted for waist circumference, systolic blood pressure, glucose levels and smoking status, only IgG1 anti-PC remained significantly associated with HO. In multivariate models, each 1 standard deviation of increment in anti-PC IgG1 levels was inversely associated with prevalence of HO (odds ratio 0.57; CI 95% 0.33–0.98; p = 0.044). IgG2 anti-PC did not show any associations with HO. Low levels of IgM and IgG1 anti-PC are associated with higher risk of being a HO individual independent of sex and age, IgG1 anti-PC also independently of diabetes and metabolic syndrome. The anti-inflammatory properties of these antibodies may be related to inflammation in obesity and its complications
SINTESIS ASAP CAIR DARI TEMPURUNG BIJI PALA DAN KARAKTERISTIK KANDUNGAN KIMIA
Limbah produk tanaman perkebunan seperti tempurung, ranting dan kayu belum tersentuh teknologi sehingga memberikan peluang untuk pengembangan teknologinya. Salah satu alternatif pengolahan adalah pirolisis sehingga menghasilkan asap cair yang dapat berfungsi sebagai pengawet dan memberikan nilai tambahan bagi petani. Tujuan penelitian yaitu mensintesis asap cair dari tempurung biji pala dan mengetahui karakteristik kimianya sebagai bahan pengawet makanan alami. Metode pelaksanaannya adalah proses pembakaran tempurung biji pala dalam wadah pirolisa selanjutnya dilakukan proses kondensasi kemudian tampung asap cair dan tar yang dihasilkan, selanjutnya dilakukan destilasi dengan menggunakan arang aktif dan diuji kandungan kimia asap cair. Hasil proses pembakaran 10 kg tempurung biji pala adalah 180cc asap cair dan tergolong sangat kecil jika dibandingkan asap cair dari tempurung kelapa. Hal ini diduga karena peralatan yang masih perlu diperbaiki. Berdasarkan hasil uji kandungan kimia, diperoleh kandungan fenol pada asap cair tempurung biji pala sebanyak 0,69% dan kandungan asam 0,15%. senyawa fenol yang bersifat antioksidan dapat menghambat kerusakan pangan. Berdasarkan hasil uji kandungan benzopiren, tidak ditemukan dalam asap cair yang telah dilakukan destilasi, sehingga asap cair ini aman digunakan sebagai pengawet alami bahan pangan. </p
2,4-Dinitro-1-naphthol
In the title compound, C10H6N2O5, the two fused rings are almost co-planar, with an r.m.s. deviation of 0.0163 Å. The nitro groups are oriented at dihedral angles of 2.62 (11) and 44.69 (11)° with respect to the plane of the parent fused rings. Intramolecular O—H⋯O and C—H⋯O hydrogen bonds complete S(6) ring motifs. In the crystal, molecules are linked into chains along [101] by intermolecular O—H⋯O hydrogen bonds. π–π interactions [centroid–centroid distances = 3.6296 (15), 3.8104 (15) and 3.6513 (14) Å] might play a role in stabilizing the structure
SNX19 restricts endolysosome motility through contacts with the endoplasmic reticulum.
The ability of endolysosomal organelles to move within the cytoplasm is essential for the performance of their functions. Long-range movement involves coupling of the endolysosomes to motor proteins that carry them along microtubule tracks. This movement is influenced by interactions with other organelles, but the mechanisms involved are incompletely understood. Herein we show that the sorting nexin SNX19 tethers endolysosomes to the endoplasmic reticulum (ER), decreasing their motility and contributing to their concentration in the perinuclear area of the cell. Tethering depends on two N-terminal transmembrane domains that anchor SNX19 to the ER, and a PX domain that binds to phosphatidylinositol 3-phosphate on the endolysosomal membrane. Two other domains named PXA and PXC negatively regulate the interaction of SNX19 with endolysosomes. These studies thus identify a mechanism for controlling the motility and positioning of endolysosomes that involves tethering to the ER by a sorting nexin
Human coronaviruses and other respiratory infections in young adults on a university campus: Prevalence, symptoms, and shedding
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145532/1/irv12563.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145532/2/irv12563_am.pd
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