Visual Examination and Photography in Failure Analysis

Failure analysis is an investigative process in which the visual observations of features present on a failed component and the surrounding environment are essential in determining the root cause of a failure. This article reviews the basic photographic principles and techniques that are applied to failure analysis, both in the field and in the laboratory. It discusses the processes involved in visual examination, field photographic documentation, and laboratory photographic documentation of failed components. The article describes the operating principles of each part of a professional digital camera. It covers basic photographic principles and manipulation of settings that assist in producing high-quality images. The need for accurate photographic documentation in failure analysis is also presented.

Analysis of damages and defects of the repair and operational unit of the compressor station

The need to maintain the technical condition of buildings with a significant service life determines the regularity of their inspection. The paper presents the analysis of the results of the inspection of the building of the repair and operational block of the compressor station. The analysis of the design documentation and the results of the measurement work showed that the construction is a one-story basementless building with dimensions of 54.62x18.74x5.9 m. The performed visual examination showed the presence of damages and defects of the third and fourth categories, which requires certain actions to eliminate them. Visual examination showed the need for instrumental examination. In particular, the need to determine the strength of brickwork and the strength of concrete in structures. The analysis of the results of the instrumental examination showed: the results of testing the wall masonry by the shock pulse method using the ONIKS 2.5 device showed that the compressive strength grade of silicate and ceramic bricks of the walls of the repair and maintenance block corresponds to M100, and the grade of masonry mortar is M50; The results of concrete testing by the non-destructive method of strength control in accordance with GOST 22690-88 with the DigiShmidt 2000 device showed that the class of concrete in terms of compressive strength in reinforced concrete slabs of the covering of the repair and operational block corresponds to B20, and the class of concrete in reinforced concrete beams of the covering corresponds to B25. The verification calculation showed that the strength of the reinforced concrete pavement of the repair and maintenance unit under the full design load acting at the time of the survey was ensured. The analysis showed that the technical condition of the maintenance and operation unit is of limited serviceability. The work provides recommendations for eliminating defects and damages.

Design and Experimental Evaluation of an Aerial Solution for Visual Inspection of Tunnel-like Infrastructures

Current railway tunnel inspections rely on expert operators performing a visual examination of the entire infrastructure and manually annotating encountered defects. Automatizing the inspection and maintenance task of such critical and aging infrastructures has the potential to decrease the associated costs and risks. Contributing to this aim, the present work describes an aerial robotic solution designed to perform autonomous inspections of tunnel-like infrastructures. The proposed robotic system is equipped with visual and thermal sensors and uses an inspection-driven path planning algorithm to generate a path that maximizes the quality of the gathered data in terms of photogrammetry goals while optimizing the surface coverage and the total trajectory length. The performance of the planning algorithm is demonstrated in simulation against state-of-the-art methods and a wall-following inspection trajectory. Results of a real inspection test conducted in a railway tunnel are also presented, validating the whole system operation.

Unilateral Laryngeal Paralysis Secondary to Otitis Media/Interna in Two Cats

ABSTRACT Two adult cats were presented for coughing, gagging, dysphonia, exaggerated swallowing attempts, unilateral vestibular dysfunction, and/or Horner syndrome. In both cats, unilateral laryngeal paralysis was identified on the side ipsilateral to other neurological deficits. Cross-sectional imaging was consistent with otitis media/interna. In both cats, there also was extensive cellulitis surrounding the tympanic bulla and dissecting through tissue planes to involve the opening of the tympano-occipital fissure on the side ipsilateral to the laryngeal paralysis. Laryngeal paralysis was presumed secondary to involvement of the vagus nerve as it emerged from the tympano-occipital fissure. Antibiotic therapy resulted in resolution of clinical signs in both cats and restored laryngeal function as evidenced by visual examination of the larynx in one cat.

The quest for palaeolithic art in the Neris river valley, Central-Eastern Lithuania

Only a few artifacts discovered in Lithuania can be considered as examples of portable art from the Final Palaeolithic period. Three of them were found in the Neris river valley in central-eastern Lithuania: an engraved slate pebble from the Eiguliai 1А site, a notched blade from the Skaruliai 1 site, and a flint “figurine” from the Vilnius 1 site. Discovered by Rimutė Rimantienė and her father Konstantinas Jablonskis, these three finds were the first and for many years the only artifacts underpinning the discussion of art from the Lithuanian Final Palaeolithic. The debate on the tentative function of these items, initiated by Rimantienė, is reviewed in this study before presenting the results of the latest research on the subject between 2012 and 2017, carried out using a range of methods: visual examination, comparative analysis with other archaeological finds and reconstructed prehistoric tools, surface analysis under a microscope. The functional interpretation proposed as a result of these investigations in two cases disproves the identification of these artifacts as portable art.

Surveillance for Patients with Oral Squamous Cell Carcinoma after Complete Surgical Resection as Primary Treatment: A Single-Center Retrospective Cohort Study

Background: The surveillance methods oral squamous cell carcinoma (OSCC) patients may be chosen by considering the risk for recurrence, and it is important to establish appropriate methods during the period in which latent/dormant cancer cells become more apparent. To investigate the appropriate surveillance of patients with OSCC based on the individual risk for recurrence and/or metastasis, we performed a retrospective cohort study after the complete surgical resection of OSCC as the primary treatment. Methods: The study was performed in 324 patients with OSCC who had been primarily treated with surgery from 2007 to 2020 at our hospital. We investigated the period, timing, and methods (visual examination, palpation and imaging using FDG-PET/CT or CECT) for surveillance in each case that comprised postsurgical treatment. Results: Regarding the time to occurrence of postsurgical events, we found that half of cases of local recurrence, cervical lymph node metastasis, and distant metastasis occurred within 200 days, and 75% of all of these events occurred within 400 days. However, the mean time for second primary cancer was 1589 days. The postsurgical events were detected earlier by imaging examinations than they were by visual examination and palpation. Conclusions: For the surveillance of patients with OSCC after primary surgery, it is desirable to perform FDG-PET/CT within 3–6 months and at 1 year after surgery and to consider CECT as an option in between FDG-PET/CT, while continuing history and physical examinations for about 5 years based on individual risk assessment.

Seam welds quality control improvement using method of pseudo-color coding images

The method of seam welds quality control using X-ray is considered. The X-ray methods of control are based on the capability of gamma radiation to penetrate through a metal including welded areas. Regions having defects - pores, faulty welds, cracks, scale inclusions - look darker on images. Appearance, linear dimensions and depths of the defects usually are determined by a visual examination comparing the X-ray image with standard defects images. It is known that a human eye can distinguish not more than 12-15 shades on a black and white image but more than a hundred on a colored image. The paper considers possibilities of the developed method by the author and based on the optical mixing of two or three complementary colors - red, blue and green. The method can use only one pair of the colors at a time, i.e. it is possible to have three various pairs for a pseudo-color image. The obtained pseudo-color image has the same informational capacity as the original black and white image. But the greater fraction of the saved information becomes available for visual examination of the X-ray image. In the end the efficiency of the seam weld quality control increases.

Automated caries detection in vivo using a 3D intraoral scanner

The use of 3D intraoral scanners (IOS) and software that can support automated detection and objective monitoring of oral diseases such as caries, tooth wear or periodontal diseases, is increasingly receiving attention from researchers and industry. This study clinically validates an automated caries scoring system for occlusal caries detection and classification, previously defined for an IOS system featuring fluorescence (TRIOS 4, 3Shape TRIOS A/S, Denmark). Four algorithms (ALG1, ALG2, ALG3, ALG4) are assessed for the IOS; the first three are based only on fluorescence information, while ALG4 also takes into account the tooth color information. The diagnostic performance of these automated algorithms is compared with the diagnostic performance of the clinical visual examination, while histological assessment is used as reference. Additionally, possible differences between in vitro and in vivo diagnostic performance of the IOS system are investigated. The algorithms show comparable in vivo diagnostic performance to the visual examination with no significant difference in the area under the ROC curves ($$p>0.05$$ p > 0.05 ). Only minor differences between their in vitro and in vivo diagnostic performance are noted but no significant differences in the area under the ROC curves, ($$p>0.05$$ p > 0.05 ). This novel IOS system exhibits encouraging performance for clinical application on occlusal caries detection and classification. Different approaches can be investigated for possible optimization of the system.

The Characterization of the Materials Used by Gino Severini in His 20th C Wall Paintings at Semsales in Switzerland

The modern decoration of the Saint Nicolas de Myre Church at Semsales (1924–1926), is the first by renowned Italian artist Gino Severini in Switzerland. Following archival research and visual examination, the materials and the techniques used by Severini for the wall paintings of this church were examined through a multi-technique analytical approach that included both non-invasive and invasive investigations. Archival research revealed lists of some of the materials purchased for the church and notes of the artists. In situ investigations included imaging methods and point analyses (X-ray fluorescence and reflection FT-IR spectroscopy). Based on non-invasive results, a limited number of representative samples were collected for laboratory invasive analyses (SEM-EDS, FTIR-FPA imaging, μ-Raman and GC-MS) to characterize the stratigraphy and the composition of the paintings. Results were coherent with artist’s notes and revealed protein-based binders, i.e. animal glue and casein, exclusively on the Trinity mural (in the apse) confirming the use of a secco technique. All the other wall paintings analyzed at Semsales are painted without the use of organic binders. These findings, integrated with archival researches and the visual examination by conservators, provided significant insights into the materials and techniques used by Gino Severini in his first Swiss murals.