A numerical modelling for the extraction of decay regions from color images of monuments

An innovative application focused on the segmentation of decay zones from images of stone materials is presented. The adopted numerical approach to extract decay regions from the color images of monuments provides a tool that helps experts analyze degraded regions by contouring them. In this way even if the results of the proposed procedure depend on the evaluation of experts, the approach can be a contribution to improving the efficiency of the boundary detection process. The segmentation is a process that allows an image to be divided into disjoint zones so that partitioned zones contain homogeneous characteristics. The numerical method, used to segment color images, is based on the theory of interface evolution, which is described by the eikonal equation. We adopted the fast marching technique to solve the upwind finite difference approximation of the eikonal equation. The fast marching starts from a seed point in the region of interest and generates a front which evolves according to a specific speed function until the boundary of the region is identified. We describe the segmentation results obtained with two speed functions, attained by the image gradient computation and color information about the object of interest. Moreover, we present the extension of the working modality of the method by introducing the possibility to extract the regions not only in a local way but also in a global way on the entire image. In this case, in order to improve the segmentation efficiency the application of the fast marching technique starts with more seed points defined as seed regions. The study case concerns the impressive remains of the Roman Theatre in the city of Aosta (Italy). In the image segmentation process the color space L^∗a^∗b^∗$L^{\ast }{a}^{\ast }{b}^{\ast }$ is utilized.     

A student design project to improve power quality for a commercialfacility

A recent paper (see ibid., vol.7, no.4, p.1550-8, 1992) reported on the success of industry-sponsored student projects to promote power quality education. One such project, sponsored by BCM Engineers in Plymouth Meeting, PA, was entitled “Power Quality Survey of a Commercial System.” The results of the survey confirmed the suspicion that power line disturbances (i.e., normal-mode and common-mode impulses and “noise”) were responsible for the outages, premature failures and data communication errors of critical microprocessor-based equipment (e.g., terminals, workstations, network file servers, teleconferencing video equipment, etc.). As a follow-up to this project, this paper reports on the results of a student design project to develop a cost-effective implementation plan to mitigate the causes of the BCM power quality problems (i.e., grounding, wiring methods, load configurations, surge protection, and employee practices). Since BCM only leases several floors of the commercial building, it was important that the design be cost-effective and unobtrusive to the other tenants in the building. The design presented is simple and effective, and it conforms to the NEC and accepted industry practice. The students have benefited from this experience by being exposed to real-world constraints on power quality design which cannot be taught in the classroom     

A comparison of dynamic security indices based on direct methods

This paper presents a comparison of direct methods for transient stability assessment. The emphasis is on stability criteria based on Lyapunov's direct method. The comparison is made by studying the similarities and differences in the regions of attraction which the direct methods define. The region of attraction is characterized in terms of a performance index (PI) and a threshold value (TH). This paper reformulates the various Lyapunov energy functions and stability criteria for the direct methods proposed in the literature in a unified mathematical notation. Specifically, each energy function is reformulated in terms of a general form of the PI and each type of stability criterion is restated in terms of a threshold value, TH. Comparison tables are presented to identify the similarities and differences in the PI parameters, threshold values and dynamic models. These tables are used to show the correctness of several relationships among the direct methods mentioned in the literature and to derive new relationships for the similarities and differences between the direct methods.     

Characterization of different strains of broiler chicken by carcass measurements, chemical and physical parameters and NIRS on breast muscle

The aims of the work were: to investigate the effect of chicken strain on chemical composition and colour parameters of fresh breast muscle; to evaluate the results obtained using different illuminants (A, C and F); to verify the possibility of predicting some meat features by near infrared reflectance spectroscopy (NIRS) of freeze-dried breast muscle. The trial was carried out on 39 chicken broilers from three strains, differing in body size, slaughtered at 30 days of age. Fresh breast samples were different only in ash content (P<0.01). Illuminant effect was highly significant for all colour variables, depending on the major wavelength characteristics of each illuminant. Significant differences among strains were detected in redness values. The NIRS technique was very accurate to predict fat content of muscle (R(2)c=0.98, SEC=0.20). These findings may have practical importance to improve instrumental procedures for on-line evaluation of poultry meat quality.     

Intercomparison of gas flow-rate measurements at IMGC, Italy, and UASG, Germany, in the range from 10 to 10 Pa m/s

Primary standard gas flow meters are developed for various applications such as calibration of leak artefacts, generation of calibration pressures by dynamic gas expansion and calibration of secondary standard gas flow meters. The Istituto di Metrologia “G. Colonnetti” (IMGC), Italy, and the University of Applied Sciences Giessen-Friedberg (UASG), Germany, maintain primary flow meters based on different principles in order to measure small gas flows delivered either to vacuum (i.e. practically zero pressure) or to atmosphere (ambient pressure). The principle, design and properties of these flow meters are described. Comparison of the primary standard flow meters maintained at these laboratories was performed over a range from 3×10⁻⁸ to 7×10⁻⁴ Pa m³/s with nitrogen, using a crimped capillary leak as a transfer standard. IMGC was the pilot laboratory. During the intercomparison, the transfer standard changed by ca. −2% for flow to vacuum and by ca. −4% for flow to atmosphere without obvious reason. The results of the intercomparison show that the laboratories agree within their expanded uncertainties over the measured range of gas flows.     

INRIM continuous expansion system as high vacuum primary standard for gas pressure measurements below 9 × 10 Pa

The continuous expansion system can be considered the state of the art for pressure measurement in the ultra high vacuum range. In the last years, at INRIM, a new continuous expansion system was designed, assembled and characterized. The system is the high vacuum primary standard in the pressure range from 1 × 10⁻⁶ Pa to 9 × 10⁻² Pa with relative standard uncertainty ranging from 2.1% at 1 × 10⁻⁶ Pa down to 0.4% at 9 × 10⁻² Pa. The system is based on the passing of a measured gas flow through a fixed and known conductance. The gas flow is generated and measured by a primary gas flowmeter based on the constant-pressure-variable-volume method.In the first part of the paper both a correction for the effect of transitional flow through the orifice and a new analytical evaluation of orifice conductance are presented. In the second part the accuracy of the system and the pressure uncertainty evaluation are described.     

INRIM primary standard for microgas-flow measurements with reference to atmospheric pressure

Primary standard flowmeters are developed for the calibration of leak devices used in many applications in which is necessary to detect and quantify gas leakage from a material, a component or a system. At INRIM, a primary standard was designed and realized for the measurement of molar gas flow from 4 × 10⁻¹⁰ mol/s to 2 × 10⁻⁷ mol/s with reference to atmospheric pressure. It is based on the constant-pressure–variable-volume method and is able to work with any tracer gas.     

An investigation of quartz type pressure transducer behavior under continuous pressure conditions and metrological characterization

In this work the behavior of high accurate quartz based pressure transducer under the continuous pressure conditions was investigated and metrologically characterized. Paroscientific digiquartz pressure transducer which belongs to the pressure laboratory of INRIM was chosen as a device. First measurements were realized in INRIM and UME in 2005. Two different measurement procedures were applied. The pressure was applied at each pressure points approximately during 25 min to observe the behavior of transducer under applied continuous pressure conditions. The results of standard calibration procedure were compared with the results of applied continuous conditions procedure. The same measurements were repeated in INRIM and UME in 2010 to compare the results taken from 2005 to 2010 and the long term stability was evaluated.     

Leak rate metrology for the society and industry

Leak detection is a non-destructive test performed to verify materials and components in agreement with the prescribed specifications, by using techniques, which do not damage their characteristics or performances. The leak check of fluids dates back in time; it started to be applied at the end of the 19th century when the electron was discovered and early in 20th century when the first mass spectrometer was realized. Today, for environmental and personal safety more effective leak detection and location capabilities on various artifacts are necessary. Leak detection techniques are widely applied in many branches of industry. In the paper leak test requirements in general and the differences between the test methods are shortly reviewed. The choice of proper leak detection technique is related to the sensitivity and leak thresholds. Whatever method is chosen, a traceability chain must be guaranteed starting from the NMIs that have developed primary standards.     

A Role for Human DNA Polymerase λ in Alternative Lengthening of Telomeres

Telomerase negative cancer cell types use the Alternative Lengthening of Telomeres (ALT) pathway to elongate telomeres ends. Here, we show that silencing human DNA polymerase (Pol λ) in ALT cells represses ALT activity and induces telomeric stress. In addition, replication stress in the absence of Pol λ, strongly affects the survival of ALT cells. In vitro, Pol λ can promote annealing of even a single G-rich telomeric repeat to its complementary strand and use it to prime DNA synthesis. The noncoding telomeric repeat containing RNA TERRA and replication protein A negatively regulate this activity, while the Protection of Telomeres protein 1 (POT1)/TPP1 heterodimer stimulates Pol λ. Pol λ associates with telomeres and colocalizes with TPP1 in cells. In summary, our data suggest a role of Pol λ in the maintenance of telomeres by the ALT mechanism.