Detecting faulty sensors in an array using symmetrical structure and cultural algorithm hybridized with differential evolution

The detection of fully and partially defective sensors in a linear array composed of N sensors is addressed. First, the symmetrical structure of a linear array is proposed. Second, a hybrid technique based on the cultural algorithm with differential evolution is developed. The symmetrical structure has two advantages: (1) Instead of finding all damaged patterns, only (N–1)/2 patterns are needed; (2) We are required to scan the region from 0° to 90° instead of from 0° to 180°. Obviously, the computational complexity can be reduced. Monte Carlo simulations were carried out to validate the performance of the proposed scheme, compared with existing methods in terms of computational time and mean square error.     

Classification of Drinking Water Quality Index and Identification of Significant Factors

Water pipes are considered to be one of responsible sources for the water pollution. Among these sources of water supply, the water pipes are the only source of carrying out fresh or processed water into lakes, ponds and streams etc. In Pakistan, knowledge on the condition of water pipes is scarce as deterioration of water pipes are hardly inspected due to high cost. The aim of the current research was to examine the quality of water pipelines of eight districts of South-Punjab, namely, Mianwali, Khushab, Layyah, Bhakkar, Dera Ghazi Khan, Muzaffargarh, Rajanpur and Rahim Yar Khan. Selected sampling stations were analyzed for physio-chemical parameters such as pH, Total Dissolve Solids (TDS), Sulfate (SO₄), Chlorine (Cl), Calcium (Ca), Magnesium (Mg), Hardness, Nitrate (NO₃), Fluoride (F) and Iron (Fe). The data pertaining water monitoring contain different parameters and seem difficult work for the interpretation of water quality by managing different parameters separately. For this purpose, National Sanitation Foundation Water Quality Index (NSF-WQI) was determined to communicate the quality of water in a simple form. Besides this, groups comprising of similar sampling sites based on water quality characteristics were identified using unsupervised technique. Factor Analysis (FA) has been performed for extracting the latent pollution sources that may cause the more variance in large and complex data. The calculated values of WQI from 1600 sampling stations ranging from 20.73 to 223.74 are divided into five groups; Excellent to Unsuitable class of waters with the average value 62.09 described as good limit for drinking water. Further sampling stations are divided into five optimal clusters selected with suitable k value obtained from Silhouette coefficient. Results of k-means clustering are also verified with natural groups made by WQI. Analysis of multivariate techniques showed several factors to be responsible for the water quality deterioration. It is found out from the FA that three latent factors such as organic pollution, agriculture run-off and urban land use caused 83.30 % of the total variation. Hence, water quality management and control of these latent factors are strongly recommended.     

Carbohydrate–Lectin Interactions: An Unexpected Contribution to Affinity

Uropathogenic E. coli exploit PapG‐II adhesin for infecting host cells of the kidney; the expression of PapG‐II at the tip of bacterial pili correlates with the onset of pyelonephritis in humans, a potentially life‐threatening condition. It was envisaged that blocking PapG‐II (and thus bacterial adhesion) would provide a viable therapeutic alternative to conventional antibiotic treatment. In our search for potent PapG‐II antagonists, we observed an increase in affinity when tetrasaccharide 1 , the natural ligand of PapG‐II in human kidneys, was elongated to hexasaccharide 2 , even though the additional Siaα(2–3)Gal extension is not in direct contact with the lectin. ITC studies suggest that the increased affinity results from partial desolvation of nonbinding regions of the hexasaccharide; this is ultimately responsible for perturbation of the outer hydration layers. Our results are in agreement with previous observations and suggest a general mechanism for modulating carbohydrate–protein interactions based on nonbinding regions of the ligand.     

Optimal Agricultural Water Allocation for the Sustainable Development of Surface and Groundwater Resources

This paper presents a multiobjective linear program for the optimal allocation of water resources among various crops in a large canal command area of Pakistan. The available surface water in the canal cannot meet the net irrigation requirement (NIR) of various crops, which leads to the overexploitation of groundwater and causes salinity problems. Therefore, an optimal water allocation model was formulated using the simultaneous compromise constraint (SICCON) technique for the sustainable development of surface water and groundwater. Three (03) single objective functions (OFs) and a multiobjective function (MOF) were considered in this study. The MOF combines the single OFs by developing an arrangement among them to both maximize the satisfaction rate for surface water (SR_s) and net economic returns (NER) and minimize the salinity problems. The available surface water (AW) of 1531 Mm³ was allocated among various crops, i.e., wheat, cotton, sugarcane, rice, onion, and sunflower, using the SICCON technique, and the deficit was accounted for with groundwater reserves. The model results showed an average increase of 22% in SR_s and 7.2 million USD in NER_s from surface water allocation compared to the current water allocation practice. Moreover, the salinity levels of the allocated water exceed the threshold limits of onion, sugarcane, and rice crops in the current water allocation system and thereby negatively impact agricultural production. Hence, the model used in this study may support decision-makers in the optimal selection of different crops to be irrigated to maximize the SR_s and NER_s and minimize salinity problems.

     

HClO4–SiO2 as a novel and recyclable catalyst for the synthesis of 2,4,6-triarylpyridines under solvent-free conditions

A simple and efficient synthesis of 2,4,6-triarylpyridines using a variety of aromatic and heteroaromatic aldehydes in the presence of solid-supported perchloric acid (HClO₄–SiO₂) as a heterogeneous catalyst at 120 °C under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, shorter reaction times (4–6 h), milder conditions and the catalyst exhibited remarkable reusable activity.     

Engineering electrospun nanofibrillar surfaces for spinal cord repair: a discussion

BACKGROUND: The design of implants comprised of biodegradable electrospun nanofibers for the purpose of bridging injuries in damaged spinal cord is discussed. Electrospun nanofibers structurally mimic the extracellular matrix on which neurons and other cell types grow in vivo. This property has created great interest for their use in tissue engineering applications. However, their employment as biomimetic surfaces for such in vivo applications is still in its infancy. RESULTS: A nonwoven fabric comprised of electrospun polyamide nanofibers supported modest axonal regeneration in injured adult rat spinal cord. Covalent modification of the nanofibers with a bioactive peptide derived from the neuroregulatory extracellular matrix molecule tenascin‐C enhanced the ability of the nanofibers to facilitate axonal regrowth. However, the random orientation of the nanofibrillar fabric folds was an impediment to the forward movement of axons. CONCLUSIONS: Polyamide nanofibers covalently modified with neuroactive molecules provide a promising material for grafts to promote spinal cord regeneration. However, for the proper guidance of regrowing axons, attention must be paid to the engineering of ordered nanofibrillar structures. Copyright © 2007 Society of Chemical Industry     

Risk-free WHO grading of astrocytoma using convolutional neural networks from MRI images

Multimedia Tools and Applications - Astrocytoma is the most common and aggressive brain tumor, in its highest grade, the prognosis is ‘low survival rate’. Spinal tap and biopsy are the...     

Local probability distribution of natural signals in sparse domains

In this paper, we investigate the local PDF of natural signals in sparse domains. The statistical properties of natural signals are characterized more accurately in the sparse domains because the sparse domain coefficients have heavy‐tailed distribution and have reduced correlation with adjacent coefficients. Our experiments on 3D data in 3D discrete complex wavelet transform domain show that a conditionally (given locally estimated variance and shape) independent Bessel K‐form distribution (BKFD) locally fits the sparse domain's coefficients of natural signals, accurately. To justify this observation, we also investigate the PDF of the locally estimated variance and suggest a Gamma PDF for the locally estimated variance. Because commonly used sparse transformations are orthonormal, the PDF of the sparse domain coefficients must converge to Gaussian distribution by virtue of central limit theorem assuming that natural signals are locally wide sense stationary for small window sizes. Interestingly, we observe that the PDF of the normalized data (on the locally estimated variance) exhibit a Gaussian PDF, which confirms that the BKFD is an appropriate fit. Copyright © 2013 John Wiley & Sons, Ltd.     

A Comparison of the Growth Kinetics and Scale Morphology for Three Superalloys at 930°C in Air and Low PO2 Environments

This study assessed the oxidation behavior of three commercial alloys in airand low partial pressures of oxygen roman (P_{O 2}. The kinetics ofoxidation in air were compared with values obtained in an atmosphere of lowroman P_{O 2}. The low partial pressure of oxygen was of the order of10–16 atm at 930°C and was generated using an H₂/4% H₂Omixture. The nature of the corrosion products, structure, morphology, andcomposition were assessed and characterized using scanning electronmicroscopy (SEM), X-ray mapping, and scanning Auger microscopy (SAM). Theresults were compared with those obtained for 99.99% pure chromium. Parabolickinetics were exhibited by all of the alloys, with the overall k_p valuesbeing of the order constant for chromia-forming alloys. Large variations inthe morphologies of the oxide scales were observed as a result of oxidationin the high and low roman P_{O 2} environments.     

Novel Electrochemical Test Bench for Evaluating the Functional Fatigue Life of Biomedical Alloys

The aim of the present work was first to develop and validate a test bench that simulates the in vitro conditions to which the biomedical implants will be actually subjected in vivo. For the preliminary application assessments, the strain-controlled fatigue tests of biomedically pure Ti and Ti–Nb–Zr alloy in simulated body fluid were undertaken. The in situ open-circuit potential measurements from the test bench demonstrated a strong dependence on the dynamic cycling and kind of material under testing. The results showed that during fatigue cycling, the passive oxide film formed on the surface of Ti–Nb–Zr alloy was more resistant to fatigue degradation when compared with pure Ti. The Ti–Nb–Zr alloy exhibited prolonged fatigue life when compared with pure Ti. The fractographic features of both materials were also characterized using scanning electron microscopy. The electrochemical results and the fractographic evidence confirmed that the prolonged functional fatigue life of the Ti–Nb–Zr alloy is apparently ascribable to the reversible martensitic phase transformation.