989 research outputs found
Material and processes selection in conceptual design
No full textMaterials and manufacturing processes are an integral part of the design of a product. The need to combine materials and manufacturing processes selection during the early stages of the design has previously been realized. The work that generally attracts the most attention is by M.F. Ashby. This methodology, like others, concentrates on materials and manufacturing processes selection after the conceptual design is completed and before moving into embodiment design.
The disadvantage of waiting until the conceptual design is completed to address materials and manufacturing processes is that the designer cannot search for conceptual solutions when dealing with issues relating to the materials and manufacturing processes domains. By not considering these issues early on in the design process, the scope for innovation is reduced and this results in the designer being fixated on the configuration at hand. It is well recognized that this is not the best way to address a design challenge and an even worse approach to innovation.
The basic framework for which enhancements and improvements are suggested is the design methodology practiced and taught by the members of the Institute for Innovation and Design in Engineering (IIDE) at Texas A&M University. Conceptual design is very much a part of the IIDE design process; but the current format concentrates on functional parameters and how to search for conceptual solutions for these, and does not highlight materials and manufacturing issues in the preliminary design stages where it could be most helpful.
The work documented in this thesis is an attempt to ensure that there is no disconnect between function oriented design and the materials and manufacturing processes that are applicable to that design. The core of the thesis is to incorporate a thought process which will help the designer during conceptual design phase to:
1. Consciously question if there materials and manufacturing issues; 2. Identify critical parameters in both of these domains; and 3. Search for conceptual solutions to these identified critical parameters
Supplemental Material - Cyfra 21.1: A Useful Tumour Marker in Pancreatic Ductal Adenocarcinoma: Cross-Sectional Study
No full textSupplemental Material for Cyfra 21.1: A Useful Tumour Marker in Pancreatic Ductal Adenocarcinoma: Cross-Sectional Study by Krishnakumar G. Kuttanchettiyar, Viswanathan Kollengode V, and Meer M. Chisthi in Cancer Control</p
Region-specific role of water in collagen unwinding and assembly
No full textConformational stability of the collagen triple helix affects its turnover and
determines tissue homeostasis. Although it is known that the presence of imino
acids (prolines or hydroxyprolines) confer stability to the molecule, little is known
regarding the stability of the imino-poor region lacking imino acids, which plays a
key role in collagen cleavage. In particular, there have been continuing debates about
the role of water in collagen stability. We addressed these issues using molecular
dynamics simulations on 30-residue long collagen triple helices, including a structure
that has a biologically relevant 9-residue imino-poor region from type III collagen
(Protein Data Bank ID: 1BKV). We characterized the conformational motion of the
molecule that differs between imino-rich and imino-poor regions using a torsional map
approach. At temperatures of 300 K and above, unwinding initiates at a common
cleavage site, the glycine-isoleucine bond in the imino-poor region. This provides
a linkage between previous observations that unwinding of the imino-poor region
is a requirement for collagenase cleavage, and that isolated collagen molecules are
unstable at body temperature. Unwinding of the imino-poor region is controlled by
dynamic water bridges between backbone atoms with average lifetimes on the order
of a few picoseconds, as the degree of unwinding strongly correlated with the loss
of water bridges, and unwinding could be either prevented or enhanced, respectively
by enforcing or forbidding water bridge formation. While individual water bridges
were short-lived in the imino-poor region, the hydration shell surrounding the entire
molecule was stable even at 330 K. The diameter of the hydrated collagen including the first hydration shell was about 14 ��, in good agreement with the experimentally
measured inter-collagen distances. These results elucidate the general role of water in
collagen turnover: water not only affects collagen cleavage by controlling its torsional
motion, but it also forms a larger-scale lubrication layer mediating collagen self-assembly
Molecular Identification of Delphinids and Finless Porpoise (Cetacea) from the Arabian Sea and Bay of Bengal
No full textJayasankar, P., Anoop, B., Rajagopalan, M., Yousuf, K.M.M., Reynold, P., Krishnakumar, P.K., Kumaran, Pl., Afsal, V.V., Krishnan, Anoop A. (2008): Molecular Identification of Delphinids and Finless Porpoise (Cetacea) from the Arabian Sea and Bay of Bengal. Zootaxa 1853 (1): 57-67, DOI: 10.11646/zootaxa.1853.1.5, URL: https://biotaxa.org/Zootaxa/article/view/zootaxa.1853.1.
ATMOSPHERIC PHASE DELAY IN SENTINEL SAR INTERFEROMETRY
No full textThe repeat-pass Synthetic Aperture Radio Detection and Ranging (RADAR) Interferometry (InSAR) has been a widely used geodetic technique for observing the Earth’s surface, especially for mapping the Earth’s topography and deformations. However, InSAR measurements are prone to atmospheric errors. RADAR waves traverse the Earth’s atmosphere twice and experience a delay due to atmospheric refraction. The two major layers of the atmosphere (troposphere and ionosphere) are mainly responsible for this delay in the propagating RADAR wave. Previous studies have shown that water vapour and clouds present in the troposphere and the Total Electron Content (TEC) of the ionosphere are responsible for the additional path delay in the RADAR wave. The tropospheric refractivity is mainly dependent on pressure, temperature and partial pressure of water vapour. The tropospheric refractivity leads to an increase in the observed range. These induced propagation delays affect the quality of phase measurement and introduce errors in the topography and deformation fields. The effect of this delay was studied on a differential interferogram (DInSAR). To calculate the amount of tropospheric delay occurred, the meteorological data collected from the Spanish Agencia Estatal de Meteorología (AEMET) and MODIS were used. The interferograms generated from Sentinel-1 carrying C-band Synthetic Aperture RADAR Single Look Complex (SLC) images acquired on the study area are used. The study area consists of different types of scatterers exhibiting different coherence. The existing Saastamoinen model was used to perform a quantitative evaluation of the phase changes caused by pressure, temperature and humidity of the troposphere during the study. Unless the phase values due to atmospheric disturbances are not corrected, it is difficult to obtain accurate measurements. Thus, the atmospheric error correction is essential for all practical applications of DInSAR to avoid inaccurate height and deformation measurements
A persistent scatterer interferometry procedure to monitor urban subsidence
No full textThis paper describes a Persistent Scatterer Interferometry procedure for deformation monitoring. Its more original part concerns an approach to estimate the atmospheric phase component. The procedure can be used to monitor deformation areas that are relatively small and are surrounded by stable areas. The proposed procedure is described step by step. The procedure can be applied using SAR data coming from different sensors. However, in this work we discuss results obtained using Sentinel-1 data. A case study is described, where the deformation is caused by water pumping associated with construction works. In this case study, a stack of 78 Sentinel-1 images were analysed. The main part of the paper concerns the analysis of the atmospheric component. A comprehensive characterization of this component is first described, considering the original non-filtered phases. This is followed by the characterization of the residual filtered phases. This analysis highlights the goodness of the proposed procedure. This is further confirmed by the analysis of two deformation time series. The procedure can work with any type of deformation phenomena, provided that its spatial extension is sufficiently small
Expression of high mobility group A2 protein inretinoblastoma and its association with clinicopathologic features.
No full textCdO-based nanostructures as novel CO2 gas sensors
No full textCrystalline Cd(OH)2/CdCO3 nanowires, having lengths in the range from 0.3 up to several
microns and 5–30 nm in diameter, were synthesized by a microwave-assisted wet chemical
route and used as a precursor to obtain CdO nanostructures after a suitable thermal treatment in
air. The morphology and microstructure of the as-synthesized and annealed materials have been
investigated by scanning electron microscopy, transmission electron microscopy, x-ray
diffraction and thermogravimetry–differential scanning calorimetry. The change in morphology
and electrical properties with temperature has revealed a wire-to-rod transformation along with
a decreases of electrical resistance.
Annealed samples were printed on a ceramic substrate with interdigitated contacts to
fabricate resistive solid state sensors. Gas sensing properties were explored by monitoring
CO2 in synthetic air in the concentration range 0.2–5 v/v% (2000–50 000 ppm). The effect of
annealing temperature, working temperature and CO2 concentration on sensing properties
(sensitivity, response/recovery time and stability) were investigated. The results obtained
demonstrate that CdO-based thick films have good potential as novel CO2 sensors for practical
applications
Neural Ordinary Differential Equations for Frequency Security Assessment
No full textTo keep pace with increasing renewable energy penetration and consequent increase in inverter-based resources in the power grid, it is pertinent for present-day research to address the resulting drop in system inertia levels and its impact on frequency stability. With decreasing levels of inherent rotational inertia present in the system, any sudden disturbance causing an energy imbalance in the grid could lead to more drastic excursions of system frequency than those experienced hitherto. To ensure the resilience of the grid in such scenarios, advanced and competent frequency stability assessment and control methods are required. This thesis presents Neural Ordinary Differential Equations (NODE), a recently introduced family of neural networks, as an effective tool to achieve fast, real time estimates of the expected frequency response trajectory during an energy imbalance event. Since high-impact frequency instability events are sparse in reality, both real-world grid data and synthetically generated data corresponding to different inertial conditions are used to train predictive NODE models. Firstly, NODE is adapted to frequency prediction applications through relevant data processing steps, and modification of network parameters and algorithmic aspects pertaining to the predictive model definition. Secondly, patterns corresponding to specific sections of the frequency response curve are used to selectively train NODE models. Pattern-specific training methods exhibit better prediction performance when the NODE model encounters frequency behaviour similar to the one it initially trained on. Thirdly, a pre-training approach to cut short on the real-time training time required by NODE models to achieve desired levels of prediction performance is presented. Fast estimates of critical frequency stability parameters like nadir could act as potential triggers for early stability control actions to achieve a more controlled frequency response.Application of predictive NODE models for different frequency scenarios are presented using three test-cases: normal operating scenario, restoration post-system split scenario and synthetically generated high-impact frequency disturbance scenarios. Model tuning and training methods specific to each test-case are described, and prediction results are evaluated with relevant performance metrics. Finally, a comparison is made between the implementation of NODE among different test-cases and real-world implications of the frequency prediction outcomes from the test-cases are further discussed.Electrical Engineerin
FIGURE 2 in Molecular Identification of Delphinids and Finless Porpoise (Cetacea) from the Arabian Sea and Bay of Bengal
No full textFIGURE 2. Illustrations of the cetaceans sampled in this study. a—Stenella longirostris: specimens CH02 & CH10 (haplotype code: IndSl2); b—Stenella longirostris: specimen Dol04 (haplotype code: IndSl5); C—Stenella longirostris: specimens Dol05 & Dol06 (haplotype code: IndSl9); d—Tursiops aduncus: specimen CH08 (haplotype code: IndTa2); e—Delphinus capensis (?): specimen Dol03 (haplotype code: IndDc2); f—Sousa chinensis: specimen MNG4 (haplotype code: IndSc1); g— Neophocaena phocaenoides: specimen MNG5 (haplotype code: IndNp1).Published as part of Jayasankar, P., Anoop, B., Rajagopalan, M., Yousuf, K.M.M., Reynold, P., Krishnakumar, P.K., Kumaran, Pl., Afsal, V.V. & Krishnan, Anoop A., 2008, Molecular Identification of Delphinids and Finless Porpoise (Cetacea) from the Arabian Sea and Bay of Bengal, pp. 57-67 in Zootaxa 1853 (1) on page 61, DOI: 10.11646/zootaxa.1853.1.5, http://zenodo.org/record/513475
- …
