150 research outputs found

    Analyse texturale pour la discrimination des classes urbaines sur des images IKONOS

    Get PDF
    High spatial resolution imagery can be a very significant source of detailed land cover and land use data necessary for better urban planning and management, which is becoming increasingly important due to the growing human population. However, traditional methods, based on spectral data, used to extract this information from remote sensing imagery have proven to be unsuitable for high-resolution images. Spatial data, or texture, has been widely investigated as a supplement to spectral data for the analysis of complex urban scenes. However, the application of these techniques on high spatial resolution imagery, such as those obtained by the IKONOS satellites, has yet to be studied. This research, therefore, focuses on the extraction of texture features through the use of the Grey Level Co-occurrence Matrix texture analysis technique, which are then combined with the spectral data in the Maximum Likelihood Classification approach, as a method for obtaining more accurate urban land cover and land use information from high spatial resolution IKONOS imagery. In this study, classifications were done using three datasets: a spatial dataset consisting of three texture channels (Mean, Homogeneity and Dissimilarity), a spectral dataset consisting of four spectral channels (Red, Green, Blue and N-IR), and a combination dataset (spatial and spectral). The results show that the spatial dataset produced an overall classification accuracy of 73.5%. The spectral dataset produced a slightly higher overall classification accuracy of 78.9%, an increase over the spatial dataset of 5.4%. The combination dataset produced the highest overall classification accuracy of 86.1%, which is an increase of 7.2% over the spectral dataset. These results demonstrate great potential for the contribution of texture and high-resolution images in deriving more accurate and detailed urban information

    Transform- and statistical-based image analysis for assessment of deterioration in concrete infrastructure

    Get PDF
    The evaluation of the condition of infrastructure requires the development and optimization of alternative inspection methods for assessing surface deterioration in order to obtain accurate and quantitative information to supplement visual inspections. To this end, non-destructive methods that produce image data show great potential and are increasingly being used in concrete applications. These methods, based on IR thermography and greyscale and colour imaging, are generally cost and time effective and are relatively easy to employ. There is, however, a need for efficient image analysis techniques to extract relevant damage information from the imagery. In this context, this research proposes the use of grey level co-occurrence matrix statistical texture analysis in combination with Haar's wavelet analysis for improved defect detection. Two classifiers are proposed, the supervised multi-layer perceptron artificial neural network and the unsupervised K -means clustering approach, for evaluation of their effectiveness in characterizing the deterioration from the imagery. These techniques are applied to thermographic, colour and greyscale imagery of laboratory specimens and field samples exhibiting different levels of concrete deterioration. Further experiments are conducted on borehole acoustic imagery involving the additional techniques of spatial filters and edge-detectors in an effort to determine their efficiency in detecting concrete damage.The results demonstrate that the hybrid texture approach is quite effective for defect discrimination. They also indicate that the lowpass and median spatial filters performed better than the gradient-based and Laplacian edge-detectors; however, the texture approaches outperformed all of the other techniques.The artificial neural network was found to provide better classification accuracies compared with the K -means algorithm. Concerning the imagery, the thermography produced more accurate results than the colour and greyscale imagery.The information derived from the imagery consists of total surface damage; for map-crack imagery, the total length of cracks and range of crack width openings were also computed.The damage quantities obtained for the laboratory specimens show good correlation with test measurements recorded for the specimens, such as expansion and impact-echo velocities

    Thermal Imaging for Enhancing Inspection Reliability: Detection and Characterization

    Get PDF
    Reliable performance of an equipment or structure depends on pre-service quality and in- service degradation of the equipment or structure under operating conditions. The role of non-destructive testing (NDT) is to ensure integrity, and in turn, reliability of equipment or structure. Besides, NDT can also monitor in-service degradation and to avoid premature failure of the equipments/structures and prevent accidents as well as save human life. Up to now, NDT has been used in various fields of applications such as the inspection o

    Augmenting the Pressure-Based Pasteurization of Listeria monocytogenes by Synergism with Nisin and Mild Heat

    Get PDF
    The current study investigated Listeria monocytogenes inactivation using mild heat with elevated hydrostatic pressure and nisin under buffered condition. A four-strain pathogen mixture was exposed to 0 (control) and up to 9 min of (1) 4 °C elevated pressure; (2) 4 °C elevated pressure and nisin; (3) 4 °C nisin; (4) heat at 40 °C; (5) 40 °C elevated pressure; (6) 40 °C elevated pressure and nisin; and (7) 40 °C nisin. Elevated hydrostatic pressure at 400 MPa (Hub880 Explorer, Pressure BioScience Inc., Easton, MA, USA) and nisin concentration of 5000 IU/mL were used in the trials. Analyses of variance were conducted, followed by Dunnett’s- and Tukey-adjusted means separations. Under conditions of these experiments, nisin augmented (p \u3c 0.05) decontamination efficacy of 40 °C heat and elevated hydrostatic pressure treatments, particularly at treatment interval of 3 min. This synergism with nisin faded away (p ≥ 0.05) as the treatment time for thermal, high-pressure, and thermal-assisted pressure processing increased. The results of our study, thus, exhibit that practitioners and stakeholders of pressure-based technologies could benefit from synergism of mild heat and nisin for short-term, high-pressure pasteurization treatments to achieve microbial safety and economic feasibility comparable to traditional heat-treated products

    Fate and Biofilm Formation of Wild-Type and Pressure-Stressed Pathogens of Public Health Concern in Surface Water and on Abiotic Surfaces

    Get PDF
    Since the historic outbreak near Broad Street in London, which serves as cornerstone of modern epidemiology, infectious diseases spread in surface and sub-surface water has been a persisting public health challenge. The current study investigated persistence of wild-type and pressure-stressed Listeria monocytogenes, Escherichia coli O157:H7, and non-typhoidal Salmonella enterica serovars in surface water stored aerobically for up to 28 days at 5, 25, and 37 °C. Additionally, biofilm formation of wild-type and pressure-stressed non-typhoidal Salmonella serovars were monitored on surface of stainless steel and rubber coupons for 28 days at 25 and 37 °C. While L. monocytogenes exhibited a lower (p \u3c 0.05) survival rate at 5 °C, relative to the two Gram-negative pathogens, at higher temperatures of 25 and 37 °C, all three pathogens exhibited similar (p ≥ 0.05) trends for survival in surface water. Both wild-type and pressure-stressed Salmonella serovars in the vast majority of tested times, temperatures, and surfaces exhibited comparable (p ≥ 0.05) persistence and biofilm formation capability. Our study thus indicates the occurrence of contamination could lead to prolonged survival of these microorganisms in low-nutrient environments and highlights the need for preventive measures such as those articulated under Produce Safety Rule of the U.S. Food Safety Modernization Act

    Synergistic Effects of Nisin, Lysozyme, Lactic Acid, and CitricidalTM for Enhancing Pressure-Based Inactivation of Bacillus amyloliquefaciens, Geobacillus stearothermophilus, and Bacillus atrophaeus Endospores

    Get PDF
    The inactivation of bacterial endospores continues to be the main curtailment for further adoption of high-pressure processing in intrastate, interstate, and global food commerce. The current study investigated the effects of elevated hydrostatic pressure for the inactivation of endospore suspension of three indicator spore-forming bacteria of concern to the food industry. Additionally, the effects of four bacteriocin/bactericidal compounds were studied for augmenting the decontamination efficacy of the treatment. Elevated hydrostatic pressure at 650 MPa and at 50 °C was applied for 0 min (untreated control) and for 3, 7, and 11 min with and without 50K IU of nisin, 224 mg/L lysozyme, 1% lactic acid, and 1% CitricidalTM. The results were statistically analyzed using Tukey- and Dunnett’s-adjusted ANOVA. Under the condition of our experiments, we observed that a well-designed pressure treatment synergized with mild heat and bacteriocin/bactericidal compounds could reduce up to \u3e4 logs CFU/mL (i.e., \u3e99.99%) of bacterial endospores. Additions of nisin and lysozyme were able, to a great extent, to augment (p \u3c 0.05) the decontamination efficacy of pressure-based treatments against Bacillus amyloliquefaciens and Bacillus atrophaeus, while exhibiting no added benefit (p ≥ 0.05) for reducing endospores of Geobacillus stearothermophilus. The addition of lactic acid, however, was efficacious for augmenting the pressure-based reduction of bacterial endospores of the three microorganisms

    Sensitivity of Planktonic Cells of Staphylococcus aureus to Elevated Hydrostatic Pressure as Affected by Mild Heat, Carvacrol, Nisin, and Caprylic Acid

    Get PDF
    Current study investigated effects of elevated hydrostatic pressure exposure in the presence of mild heat and natural antimicrobials against Staphylococcus aureus. Hydrostatic pressure of 350 to 550 MPa with nisin (5000 IU/mL), carvacrol, or caprylic acid (0.5% v/v) were applied for the reduction in four-strain mixture of S. aureus in HEPES buffer at 4 and 40 °C for up to 7 min. Results were statistically analyzed by ANOVA and D-values were additionally calculated using best-fitted linear model. Prior to exposure to treatments at 4 °C, counts of the pathogen were 7.95 ± 0.4 log CFU/mL and were reduced (p \u3c 0.05) to 6.44 ± 0.3 log CFU/mL after 7 min of treatment at 450 MPa. D-value associated with this treatment was 5.34 min (R2 = 0.72). At 40 °C, counts were 8.21 ± 0.7 and 5.77 ± 0.3 log CFU/mL before and after the 7-min treatments, respectively. D-value associated with 40 °C treatment was 3.30 min (R2 = 0.62). Application of the antimicrobials provided additional pathogen reduction augmentation for treatments \u3c 5 min. The results of the current study could be incorporated for meeting regulatory requirements such as Food Code, HACCP, and Preventive Control for Human Food of Food Safety Modernization Act for assuring microbiological safety of products against this prevalent pathogen of public health concern

    Hepatoprotective role of fruit extract of Terminalia arjuna in acetaminophen intoxicated mice

    Get PDF
    Background: Liver injury and dysfunction is one of the major health concerns throughout the world. Several herbal formulations are reported to exert beneficial effects on the biochemistry of the liver.Methods: Therefore, the current project is conducted to evaluate the hepatocurative and hepatoprotective potential of Terminalia arjuna by using albino mice.Results: The fruit extract (400 mg/Kg) of the plant showed hepatoprotective effects upon pre-treatment for 5, 10 and 15 days and later challenged with acetaminophen (400 mg/Kg) for 3 days. The results showed substantial protective properties as there was comparatively less damage to the liver. Furthermore, the fruit extract of T. arjuna also exhibited hepatocurative effects when animals were given acetaminophen (400 mg/Kg) for 3 days to damage the liver followed by the treatment with the plant extract (400 mg/Kg) for 5, 10 and 15 days. The results also indicated hepatocurative activities, as the elevated serum levels of hepatic enzymes were inclining to normal ranges in a time-dependent manner.Conclusion: In conclusion, the fruit extract of T. arjuna possesses hepatoprotective plus hepatocurative activities.Keywords: Acetaminophen; Hepatocurative; Hepatoprotective; Serum Enzymes; Terminalia arjun

    Acoustic Emission (Ae) Techniques For The Damage Assessment Of Structures.

    Get PDF
    Reinforced concrete (RC) has been facing several types of damage mechanism during their lifetime. The types of common defects in concrete structures are crack formation, corrosion, scalling and etc. Therefore a non destructive evaluation method such as Acoustic Emission (AE) is required for assessing the condition of the RC structures. AE testing in RC structures shows great potential in monitoring and assessing the health conditions of structures. AE is used as a tool to detect, identify, locate and quantify a variety of damage mechanism
    corecore