Purpose
In recent years, additive manufacturing (AM) technology has been acknowledged as an efficient method for producing geometrical complex objects with a wide range of applications. However, ...dimensional inaccuracies and presence of defects hinder the broad adaption of AM procedures. These factors arouse concerns regarding the quality of the products produced with AM and the utilization of quality control (QC) techniques constitutes a must to further support this emerging technology. This paper aims to assist researchers to obtain a clear sight of what are the trends and what has been inspected so far concerning non-destructive testing (NDT) QC methods in AM.
Design/methodology/approach
In this paper, a survey on research advances on non-destructive QC procedures used in AM technology has been conducted. The paper is organized as follows: Section 2 discusses the existing NDT methods applied for the examination of the feedstock material, i.e. incoming quality control (IQC). Section 3 outlines the inspection methods for in situ QC, while Section 4 presents the methods of NDT applied after the manufacturing process i.e. outgoing QC methods. In Section 5, statistical QC methods used in AM technologies are documented. Future trends and challenges are included in Section 6 and conclusions are drawn in Section 7.
Findings
The primary scope of the study is to present the available and reliable NDT methods applied in every AM technology and all stages of the process. Most of the developed techniques so far are concentrated mainly in the inspection of the manufactured part during and post the AM process, compared to prior to the procedure. Moreover, material extrusion, direct energy deposition and powder bed processes are the focal points of the research in NDT methods applied in AM.
Originality/value
This literature review paper is the first to collect the latest and the most compatible techniques to evaluate the quality of parts produced by the main AM processes prior, during and after the manufacturing procedure.
Use of gaming technology to bring bridge inspection to the office Omer, Muhammad; Margetts, Lee; Hadi Mosleh, Mojgan ...
Structure & infrastructure engineering/Structure and infrastructure engineering,
10/3/2019, 2019-10-03, Letnik:
15, Številka:
10
Journal Article
Recenzirano
Odprti dostop
This paper proposes a novel method for bridge inspection that essentially digitises bridges using Light Detection and Ranging (LIDAR) so that they can be later inspected in a virtual reality (VR) ...environment. The work uses conventional terrestrial LIDAR together with affordable VR hardware and freely available software development kits originally intended for authoring computer games. The resulting VR app is evaluated for a case study involving a typical masonry bridge, comparing the proposed technique with traditional inspection methods. The new approach promises to be highly effective in terms of interpretation of results, accessibility to critical areas and safety of inspectors. The work represents an important step towards the creation of digital twins of important assets in the built environment. Recent bridge collapse incidents have affected local economies, traffic congestion, and in some extreme cases led to a loss of life. The work is timely as law making agencies are paying greater attention to structural rehabilitation. This paper will be of particular interest to bridge engineers, construction professionals and law makers and could lead to future revisions of bridge inspection processes and standards.
Assessment of Feed Quality by Non-destructive Methods Adina-Mirela Ariton; Andra-Sabina Neculai-Văleanu; Cătălina Sănduleanu ...
Lucrări științifice zootehnie şi biotehnologii,
06/2023, Letnik:
56, Številka:
1
Journal Article
Odprti dostop
For the optimal optimization of feed ration, it is crucial to assess the quality of the forage feed to dairy cows. To have a good production of milk and meat on a cattle farm, the farmers must ...collaborate with the nutrition and feed control laboratories in order to formulate in a timely manner feed that is nutritionally sound Non-destructive procedures provide benefits such as high sensitivity and minimal sample preparation. The portable instruments of near infrared spectroscopy can be utilized in "on line" and" modes, removing the need for lengthy response times and allowing for fast intervention in the prevention and/or correction of disorders. When determining the feed ratio for dairy cows, one of the physical parameters that are considered is nitrogen, and implicitly the protein level, which can also be readily measured using the Dumas analysis method. The paper presents the analysis of the protein content of various vegetable substrates with that are fed to dairy cows, results obtained by applying both destructive and non-destructive techniques.
The article presents the results of experimental research and numerical analyses, and also shows the usefulness of the random forest algorithm and the support vector machine for the non-destructive ...identification of the moisture content of brick walls in historic buildings. To train and test the models, a representative dataset, including 290 sample sets and 7 predictor variables, was used. These variables are: Y - describing the year of construction of the building; XD, XM, Um - describing the wall's moisture; XC, XS, XA - describing the concentration of salts in the wall. The analyses showed that the random forest algorithm is the most predisposed model for the non-destructive assessment of the Umc mass moisture content of brick walls in historic buildings. This is proved by the highest value of the R2, amounting to 0.968, and the lowest values of RMSE, MAE and MAPE, amounting to 1.080%, 0.791 and 14.28%, respectively.
•The application of ML to assess Um of brick walls in historic buildings.•Training and testing of the algorithms carried out on a representative data set.•Experimental research with the use of non-destructive methods.•Numerical analyses with the use of RF and SVM.•A comparison of the results obtained with the use of RF, SVM and ANN.
Core Ideas
A mid‐infrared spectral library containing 20,000+ samples was reported.
Twelve soil physical and chemical properties were predicted with MIR spectra.
ANN models performed better than PLSR ...for most soil properties.
Horizon and taxonomic order as auxiliary variables improved prediction for PLSR.
MIR library has the potential as an alternative to laboratory‐based analysis for OC and IC.
Mid‐infrared (MIR) reflectance spectroscopy is commonly studied as a rapid and nondestructive method for predictive soil analysis under laboratory conditions. The first objective of this paper is to report an MIR spectral library based on 20,000+ soil samples collected from the United States. The second objective is to assess, using partial least squares regression (PLSR) and artificial neural networks (ANN), the performance of the library to predict 12 physical and chemical soil properties: organic carbon (OC), inorganic carbon (IC), total carbon (TC), total nitrogen (TN), clay, silt, sand, Mehlich‐3 extractable phosphorus (P), NH4OAc extractable potassium (K), cation exchange capacity (CEC), total sulfur (TS), and pH. The third objective is to investigate whether the use of auxiliary variables of master horizon (HZ), taxonomic order (TAXON), and land use land cover (LULC) would improve MIR model performance. The results showed that OC, IC, TC, TN and TS were predicted most satisfactorily with R2 > 0.95 and RPD (ratio of performance to deviation) > 5.5. Soil CEC, pH, clay, silt, and sand were also predicted satisfactorily with R2 > 0.75 and RPD > 2.0. P and K were predicted poorly, with R2 < 0.4 and RPD < 1.4. The ANN models generally outperformed PLSR models, except for clay, silt and sand. Using auxiliary variables (HZ, TAXON, and LULC) to develop stratified models generally improved model performance. The HZ‐specific models showed the greatest improvements. Using an MIR spectral library for routine soil analysis would positively impact many modern applications where high spatial resolution, quantitative soil data are demanded.
El uso del riego es esencial para aumentar la productividad de los cultivos, sin embargo, para el manejo eficiente del agua, es necesario estimar con mayor precisión la humedad del suelo. Por esta ...razón, el objetivo en este trabajo fue calibrar sensores de reflectometría de dominio de frecuencia FDR modelo 10HS (Decagon Devices) para ser utilizados en un suelo Geric Xanthic Ferralsol. Para la calibración fueron utilizadas muestras no disturbadas de suelo colectadas a dos profundidades (0-20 cm y 20-40 cm) en cilindros de PVC, con cuatro repeticiones cada una. Las muestras, dentro de cilindros de PVC, fueron colocadas en bandejas con agua destilada hasta alcanzar la saturación y los sensores fueron introducidos en las muestras para obtener la humedad en el punto de saturación. Posteriormente, las muestras fueron colocadas en estufa a 60 gradosC, hasta llegar aproximadamente a 10 % de humedad. Los resultados muestran que los datos de humedad volumétrica registrados antes de la calibración no coincidieron con la recta 1:1 y presentaron comportamiento divergente, evidenciando así la necesidad de calibración. Se concluye que las ecuaciones generadas antes de la calibración sobreestimaron la humedad volumétrica y las ecuaciones obtenidas después de la calibración miden satisfactoriamente la humedad del suelo Geric Xanthic Ferralsol Palabras clave adicionales: Capacitancia, constante dieléctrica, métodos no destructivos The use of irrigation is essential to increase crop productivity; however, for efficient water management, it is necessary to more accurately estimate soil moisture. For this reason, the objective in this work was to calibrate FDR model 10HS frequency domain reflectometry sensors (Decagon Devices) for use in a Geric Xanthic Ferralsol type soil. For the calibration, non disturbed soil samples were collected in PVC pipes at two depths (0-20 and 20-40 cm), with four repetitions each and they were placed in trays with distilled water until saturation. Subsequently the sensors were introduced in the sample to obtain the moisture at the saturation point. Then, the samples were placed in an oven at 60 degreesC, until they reached approximately 10 % humidity. The results showed that the gross volumetric moisture data recorded before calibration did not coincide with the 1:1 line, presenting divergent behavior, thus demonstrating the need for calibration. According to the results, it is concluded that the equations generated with the data before the calibration overestimated the volumetric soil moisture, and the equations obtained after the calibration satisfactorily measure the moisture of the Geric Xanthic Ferralsol type soil. Additional keywords: Capacitance, dielectric constant, non-destructive methods
The degradation of marine ecosystems is a growing concern worldwide, emphasizing the need for efficient tools to assess their ecological status. Herein, a novel ecosystem-based ecological evaluation ...index of shallow rocky reefs is introduced and tested in the Aegean and Ionian Seas (NE Mediterranean). The index focuses on a specific set of pre-selected species, including habitat-forming, key, commercially important, and non-indigenous species, across a wide range of trophic levels (1.00–4.53). Data acquisition is conducted through rapid non-destructive SCUBA diving surveys to assess all macroscopic food web components (macroalgae, invertebrates, and fish). Two versions of the index, ECOfast and ECOfast-NIS, were developed, each applying a different approach to account for the impact of non-indigenous species. In our case study, the correlations between the two versions of the index and sea surface temperature, protection status, occurrence of carnivorous fish, and non-indigenous herbivores were assessed through generalized additive models (GAMs). The assessment assigned 93% (ECOfast) or 96% (ECOfast-NIS) of the sites to a moderate to bad ecological status, indicating an alarming situation in the shallow rocky reefs of the NE Mediterranean. Sites evaluated as poor or bad were characterized by extensive coverage of ephemeral macroalgae, absence or minimal presence of large indigenous carnivorous fish, and complete absence of one to three out of five invertebrate functional trophic groups. The community composition of macroalgae, herbivorous species, and carnivorous fishes differed between the 5 m and 15 m depth zones. Surface temperature and carnivorous fish occurrence were the most important tested predictors of the ecological status of shallow rocky reefs. The best GAMs showed that the ECOfast score declined with sea surface temperature and increased with the occurrence of carnivorous fish; ECOfast-NIS declined with sea surface temperature and the occurrence of non-indigenous fish and increased with the occurrence of carnivorous fish. The non-destructive and integrative nature of this approach, its speed of data acquisition and analysis, and its capacity to account for highly mobile predatory fish and non-indigenous species render the ECOfast index a novel, robust, and valuable tool for assessing the ecological status of shallow rocky reefs.
Display omitted
•Development of ECOfast, an ecological evaluation index of shallow rocky reefs.•An ecosystem-based index, with sub-indices for macroalgae, invertebrates and fish.•Accounts for highly mobile fish and the negative impacts of non-indigenous species.•ECOfast tested in Greece – most reefs found at a moderate to bad ecological status.•Easily adjusted for the assessment of rocky reefs in other regions of the world.
Mycotoxins are the foremost naturally occurring contaminants of food products such as corn, peanuts, tree nuts, and wheat. As the secondary metabolites, mycotoxins are mainly synthesized by many ...species of the genera Aspergillus, Fusarium and Penicillium, and are considered highly toxic and carcinogenic to humans and animals. Most mycotoxins are detected and quantified by analytical chemistry-based methods. While mycotoxigenic fungi are usually identified and quantified by biological methods. However, these methods are time-consuming, laborious, costly, and inconsistent because of the variability of the grain-sampling process. It is desirable to develop rapid, non-destructive and efficient methods that objectively measure and evaluate mycotoxins and mycotoxigenic fungi in food. In recent years, some spectroscopy-based technologies such as hyperspectral imaging (HSI), Raman spectroscopy, and Fourier transform infrared spectroscopy have been extensively investigated for their potential use as tools for the detection, classification, and sorting of mycotoxins and toxigenic fungal contaminants in food. HSI integrates both spatial and spectral information for every pixel in an image, making it suitable for rapid detection of large quantities of samples and more heterogeneous samples and for in-line sorting in the food industry. In order to track the latest research developments in HSI, this paper gives a brief overview of the theories and fundamentals behind the technology and discusses its applications in the field of rapid detection and sorting of mycotoxins and toxigenic fungi in food products. Additionally, advantages and disadvantages of HSI are compared, and its potential use in commercial applications is reported.
•Two incorporation modes of hydrophobic agents in mortar are compared.•The emulsion affects the setting, mechanical properties and autogenous deformations.•The microencapsulation decreases these ...effects on the early age behaviour of mortars.
Over the last 15 years, bulk hydrophobic treatment of cementitious materials with silanes and siloxanes is in the scientific focus. They are beneficial in terms of reducing water uptake by capillarity, however, this is often followed by an impact on cement hydration leading to the decrease in structural properties of cement matrix. The aim of this paper is to study the influence of different incorporation modes of a silicone-based hydrophobic agent used for the bulk hydrophobic treatment of mortars, and to evaluate their effect on cement hydration and the early age properties. Two different incorporation modes are compared: an emulsion of silane and silicone resin and microencapsulation of silicone resin. Each of these is incorporated in mortars prepared with CEM I and CEM III/A. Based on the combined measurement of isothermal calorimetry, electrical resistivity, ultrasonic pulse velocity, compressive strength, thermal expansion coefficient and autogenous deformation at early age, it is shown that the emulsion, as a delivery method of hydrophobic agent, affects the early age mechanical behavior of cement-based systems, for both types of cements. The microencapsulation on the other hand, prevents these effects from occurring, and is therefore suitable for bulk hydrophobic treatment.
The freshness of anchovies (Engraulis Encrasicolus) was estimated by radio-frequency and optical techniques in order to propose non-destructive and objective methods for rapid screening. Measurements ...were conducted until 7 days at 0 °C, storing the fish under ice. Image analysis, dielectric spectroscopy and hyperspectral images were conducted on fish eyes whilst mechanical properties were measured on the fish body. Evaluation of images by RGB scale highlighted differences due to ageing. Maximum force decreased as a function of degradation process time. Cluster analysis on dielectric spectra and 3D-principal component analysis on hyperspectral images of fish eyes revealed a good ability to characterise ageing modification demonstrating suitable methods for the development of a non-destructive, and rapid system for evaluation of fish freshness.
Display omitted
•Anchovies freshness was measured by dielectric spectroscopy & hyperspectral imaging.•Dehydration of anchovy eyes was exploited for ageing estimation.•Multivariate approaches allowed to group the samples according to storage days.•Both techniques are rapid and contactless being promising for practical application.
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