Functional approximation using artificial neural networks in structural mechanics

The artificial neural networks (ANN) methodology is an outgrowth of research in artificial intelligence. In this study, the feed-forward network model that was proposed by Rumelhart, Hinton, and Williams was applied to the mapping of functions that are encountered in structural mechanics problems. Several different network configurations were chosen to train the available data for problems in materials characterization and structural analysis of plates and shells. By using the recall process, the accuracy of these trained networks was assessed

X-ray Absorption Near Edge Structure of FePt nanoclusters

X-ray Absorption Near Edge Structure [XANES] of FePt nanoclusters has been studied using a full multiple scattering, self-consistent field [SCF], real-space Green`s function approach realized via the powerful ab initio FEFF8 code. One purpose of our study is to determine the sensitivity of Pt L3 edge with respect to the size and shape of the FePt nanoclusters. We also give the results of the calculations with respect to the Fe L3 edge. Calculations are made with and without core-hole for two main reasons, to check and cross-check the FEFF code and also since in some cases it is known such as Pt clusters that better results are obtained without the core-hole. This is mainly because the screening electron will occupy empty d or f states and correspondingly reduce the white line intensity.Comment: TeX version 3.14159, LaTex2e, 6 pages with 6 figure

Quality of dried carrot pomace powder as affected by pretreatments and methods of drying

In order to develop dried carrot pomace of high quality, experiments were conducted in completely randomized design (CRD).  The carrot pomace was subjected to various blanching pretreatments i.e. water blanching (WB), steam blanching (SB), citric acid blanching (CB) and potassium metabisulphate (KMS) dipping after blanching (WBS).  A control sample (untreated, UT) was kept for comparison.  The samples were further dried by various drying methods i.e. convective drying (55°C and 65°C), sun drying and solar drying.  The 65°C convective dried samples witnessed minimum drying time with higher fiber, total carotenoids, β-carotene content and minimum change in color parameters.  Among the blanching pretreatments, the CB pretreatment showed better efficacy in retaining the quality attributes.  Overall, the CB pretreatment followed by convective drying at 65°C was found to be the best drying combination for retaining the quality attributes of carrot pomace.   Keywords: Carrot pomace, pretreatments, blanching, drying, physicochemical propertie

Lumbar morphometry: A study of lumbar vertebrae from a Pakistani population using computed tomography scans

Study design: A cross-sectional study.Purpose: To describe the characteristics of lumbar vertebrae of Pakistani patients reporting at a tertiary care hospital and compare with studies from other populations.Overview of literature: Several studies have been conducted to determine morphometry of lumbar vertebrae. Most of the studies involve Caucasian populations, still data on other populations still sparse. This is the first study describing lumbar morphometry of a Pakistani population.Methods: An observational study was conducted based on a review of thin-cut (3 mm) computed topographic images of lumbar vertebrae. Two-hundred and twenty vertebrae from forty-nine patients were studied, and various dimensions were analyzed.Results: Generally, the size of the vertebrae, vertebral canals and recesses were found to be greater in male patients. The difference was statistically significant for transverse and anteroposterior diameters of the vertebral bodies and sagittal diameter of pedicles on the left side (p\u3c0.05). Comparison of populations revealed statistically significant differences in pedicle dimensions between Pakistani population and others.Conclusions: This study provides anatomical knowledge of the lumbar region in a sample population of Pakistan. There were significant differences in various dimensions of lumbar vertebrae between female and male patients. This would prove to be critical for performing a safe operation

Material Data Representation of Hysteresis Loops for Hastelloy X Using Artificial Neural Networks

The artificial neural network (ANN) model proposed by Rumelhart, Hinton, and Williams is applied to develop a functional approximation of material data in the form of hysteresis loops from a nickel-base superalloy, Hastelloy X. Several different ANN configurations are used to model hysteresis loops at different cycles for this alloy. The ANN models were successful in reproducing the hysteresis loops used for its training. However, because of sharp bends at the two ends of hysteresis loops, a drift occurs at the corners of the loops where loading changes to unloading and vice versa (the sharp bends occurred when the stress-strain curves were reproduced by adding stress increments to the preceding values of the stresses). Therefore, it is possible only to reproduce half of the loading path. The generalization capability of the network was tested by using additional data for two other hysteresis loops at different cycles. The results were in good agreement. Also, the use of ANN led to a data compression ratio of approximately 22:1

Clear Experimental Signature of Charge-Orbital density wave in Nd1−x_{1-x}Ca1+x_{1+x}MnO4_{4}

Single Crystals of Nd$_{1-x}$Ca$_{1+x}$MnO$_{4}$ have been prepared by the travelling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-orbital ordering in this material using heat capacity measurements. Our heat capacity measurements indicate a clear transition consistent with prior observation. We find two main transitions, one at temperature $T_{_H}=310-314$ K, and other at $T_{_A}=143$ K. In addition, we may also conclude that there is a strong electron-phonon coupling in this material.Comment: 7 pages, 8 figure

spectrum of acquired demyelinating disorders of the central nervous system in adults in a tertiary care hospital

Acquired demyelinating disorders of the central nervous system are diverse group of conditions characterized by destruction or disturbance of myelin sheath in the central nervous system i.e. brain and spinal cord. These vary in their causes, clinical presentations, and prognosis

The Evaluation of Geotechnical Properties of Precambrian Hazara Slates, Hazara-Kashmir Syntaxis, Azad Kashmir, Pakistan

The fold and thrust belt of the eastern Hazara division characterised the sedimentary rocks of Precambrian toPaleocene age. The sequence and formation of Precambrian signify the oldest rock unit as Hazara Slate. Geologicalmap of the study area was prepared at the scale of 1:75,000 for about 140 square kilometre area located inMuzaffarabad (Azad Kashmir) district and Lohargali of Abbottabad (Khyber Pakhtunkhwa) district. The lab analysisshows that it is not rational to use Hazara slates as aggregate material due to its mineral accumulation and composition.Los Angele’s Abrasion Value, Impact Value, Crushing Value, Specific Gravity, Water Absorption, Flakiness Index,Elongation Index, Porosity Value, California Bearing Ratio test and Grain Size Analysis were done and co-related withB.S standards and the parameters were deduced. It was observed that the mineral composition of Hazara Slates rangesfor illite, kaolinite, quartz and carbonate. Kaolinite and illite are clay minerals which haveswelling potential to causeconstruction material damage the material. The presence of Carbonate and Quartz gives strength to the material, but itspercentage is low. Reserves calculation of different localities was also done for the quarry development