The shadow moiré method is used in conjuction with a liquid crystal display (LCD) projection panel onto which is written a computer-generated grating to display contours of the topography of objects. The ability to change rapidly the parameters of the grating such as the pitch and width of lines using software makes this a versatile tool for shadow moiré applications. This versatility of the LCD grating is made use of in this paper for rapid digital enhancement of the shadow moiré patterns.
Magneto-acoustic emission is generally found to be dependent on microstructural and compositional parameters. It is also sensitive to stress. In order to explore the potential of the MAE technique in nondestructive evaluation of ferromagnetic materials, experiments were conducted using a C-core electromagnet to magnetize samples of pipeline steel. The observed MAE, which depends on the macroscopic magnetic properties, was also found to depend on the sample size. The observed MAE waveforms for different sizes were analysed in terms of the field dependence of their rms voltage, pulse-height distribution and power spectral density. It was found that the true MAE response of the samples is distorted by interference from other acoustic interactions in the samples. The various parameters used to quantigy the MAE response are also discussed.
Composite materials are more and more used in high technology industries owing to their unique mechanical properties. For such heterogeneous and quasi-periodic materials, classical non-destructive evaluation (NDE) methods prove very unsatisfactory, and even often inapplicable. Our aim here is to investigate the particular case of ultrasonic NDE of fibre-reinforced composite materials.When using the classical A-scan echography method, it is difficult to interpret time diagrams. This is mainly due to the heterogeneous nature of the materials, the complexity of the diagrams being especially increased by the occurrence of distributed defects (like porosities).Using spectral analysis techniques (ultrasonic spectroscopy), information may be extracted from these intricate time diagrams. In particular, the occurrence of a selective absorption frequency in both the transmitted and reflected energy spectra is evident. This absorption phenomenon is clearly related to the material structure and periodicity and advantage may then be taken of its characteristics (centre frequency, bandwidth and relative depth of the absorption dip in the spectrum) to characterize the material and identify the presence of defects or porosities.
The ultrasonic dry-couplant technique has been used to evaluate adhesive bonds in honeycomb and aluminium-fibre reinforced plastic-aluminium sandwich materials. The technique does not require conventional liquid couplant. Both pitch-catch and through transmission methods were adopted. Disbonds have been successfully detected and evaluated using the technique.
One of the crack-like defects implemented at the inside surface of the ZB2 thick-walled pressure vessel simulating a nuclear reactor pressure vessel was locally monitored by acoustic emission. The measurement system was broadband (0.5-5 MHz) and allowed a three-dimensional location of the source. The vessel was submitted to different tests. Signals were recorded at the second series of hydrotests and at the fatigue test at 50-degrees-C. The signals were classed according to their current or non-recurrent character. The measurements are discussed by describing the signals by measurement, signal and source parameters to identify the source mechanism and to assess of the growth of the defect.All the sources active during the hydrotests were situated in the artificial defect; the identification of the mechanisms at loading remains open. During the fatigue test, the sources were also situated in the artificial defect except one located in the base material ahead of the artificial defect; this source, which was attributed to a primary mechanism, could be used to determine the growth of the defect during the fatigue test on the basis of linear elastic fracture mechanics. A secondary mechanism is suggested for recurrent sources active at loading. All the sources active at unloading are attributed to a secondary mechanism.
In the iron smelting process, slag, which is production waste, usually forms the majority of remains found at ancient metallurgical sites. In Ban Kruat, Buriram Province, Northeast Thailand, at least 50 slag-bearing sites have so far been documented, which can be divided into nine clusters. One of the clusters, Ban Sai Tho 7 group, demonstrates a quite unique spatial organisation of slag mounds. Here, 10–11 mounds of circular or ellipsoid shape were found surrounding a flat area of 350 × 400 m. Two different stages of iron production were identified between these two areas: iron smelting at the circular mounds and iron smithing on the central plain. Compared with the nearby neighboring heap, this is a comparatively large concentration of slag, and possibly illustrates the long dynamic history of iron-smelting production. Although in 2009 and 2010, this site was estimated to have existed in the Iron age by accelerator mass spectrometric (AMS) dating of in-slag charcoal, the result only reveals the early production of iron-smelting regarding the law of superposition. Therefore, in order to assess the duration of production, optically stimulated luminescence (OSL) dating was employed to date technical ceramics (i.e., furnaces and tuyères) from the topmost layers of the surface slag heap in order to indicate the late or terminal iron-smelting production. The dates of the technical ceramics that came from the different sides of the slag heap show two different periods: the early 10th to the early 11th centuries (around 1000–1100 years ago) and the early 17th century (around 370 years ago). More significantly, the old samples were at the edge of the southern part, while the young samples came from the topmost of the northeastern slag heap. Therefore, these two furnaces were possibly used in different periods and distributed in different areas of the slag heap. The result also illustrates the terminal period (the early 17th century) of metallurgy in the ancient Angkor highlands, particularly at the Ban Sai Tho 7 site. An iron-smelting activity at Ban Sai Tho 7 seems to exist in the same location for several centuries. Moreover, OSL dating is an alternative method to directly date the late period of iron-smelting production.
In this paper, the performance and economic analysis of a heat pump water heater assisted regenerative solar still using latent heat storage was experimentally studied. The heat released during condensation of water vapour inside the solar still was regenerated using a heat pump to pre-heat the saline water before entering the basin and producing hot water for domestic use. The experimental observations have been made under the influence of solar irradiation, ambient temperature and ambient wind speed. The results showed that the heat pump water heater assisted regenerative solar still has attained cumulative productivity between 14.0 and 16.0 kg/day during 12 h of operation. Moreover, the system delivers more than 100 L of hot water at 46.8–52.8 °C for domestic use. The monthly average coefficient of performance of the heat pump was estimated in the range between 2.21 and 2.55. The cost per litre of distillate obtained from the system is estimated as 0.05471 USD. The payback period was estimated as 21.46 months for 275 days of operation in a year at 12% interest and distillate selling price of 0.08 USD/litre. The water samples obtained from the experiments are suitable for drinking and met the Bureau of Indian Standard requirements.
The electrification of heating, cooling, and transportation to reach decarbonization targets calls for a rapid expansion of renewable technologies. Due to their decentral and intermittent nature, these technologies require robust planning that considers non-technical constraints and flexibility options to be integrated effectively. Energy system models (ESMs) are frequently used to support decision-makers in this planning process. In this study, 116 case studies of local, integrated ESMs are systematically reviewed to identify best-practice approaches to model flexibility and address non-technical constraints. Within the sample, storage systems and sector coupling are the most common types of flexibility. Sector coupling with the transportation sector is rarely considered, specifically with electric vehicles even though they could be used for smart charging or vehicle-to-grid operation. Social aspects are generally either completely neglected or modeled exogenously. Lacking actor heterogeneity, which can lead to unstable results in optimization models, can be addressed through building-level information. A strong emphasis on cost is found and while emissions are also frequently reported, additional metrics such as imports or the share of renewable generation are nearly entirely absent. To guide future modeling, the paper concludes with a roadmap highlighting flexibility and robustness options that either represent low-hanging fruit or have a large impact on results.
The Journal encourages and welcomes submissions of general interest to emergency nurses for the Update section. Please refer to the Instructions for Authors section for specific advice on manuscript preparation. All materials should be sent to the Managing Editor, Journal of Emergency Nursing, PO Box 489, Downers Grove, IL 60515; E-mail: [email protected].
This guide describes 11 designs of IIW-type ultrasonic calibration blocks. The designation 'IIW-type block' specifically recognizes that these designs are different from the authentic International Institute of Welding 'IIW Calibration Block 1'. In order to avoid introducing new nomenclature, the designs are given as numbered examples. The designs cited are generally made of steel.
