Deterioration Of Components Research Articles

I3oT (Industrializable Industrial Internet of Things) Tool for Continuous Improvement in Production Line Efficiency by Means of Sub-Bottleneck Detection Method

The present paper shows how to develop an I3oT (Industrializable Industrial Internet of Things) tool for continuous improvement in production line efficiency by means of the sub-bottleneck detection method. There is a large amount of scientific literature related to the detection of bottlenecks in production lines. However, there is no scientific literature that develops tools to improve production lines based on the bottlenecks that go beyond rebalancing tasks. This article explores the concept of a sub-bottleneck. In order to detect sub-bottlenecks in a massive way, the use of one of the I3oT (Industrializable Industrial Internet of Things) tools developed in our previous work, the mini-terms, is proposed. These mini-terms use the existing sensors for the normal operation of the production lines to measure the sub-cycle times and use them to predict the deterioration of the machine components found in the production lines. The sub-bottleneck algorithms proposed are used in two real twin lines at the Ford manufacturing plant in Almussafes (Valencia), the (3LH) and (3RH), to show how the lines can be continuously improved by means of sub-bottleneck detection.

Holistic maintenance management for higher learning institution buildings in Tanzania

PurposeThere have been claims of inadequate maintenance practice in Tanzania’s higher learning institutions (HLIs), primarily due to the traditional conventional approach where maintenance is only addressed during the usage stage. This study aimed to investigate whether universities and colleges are adopting a holistic approach to maintenance, where it is considered from the inception stage.Design/methodology/approachStructured questionnaires and semi-structured interviews were employed to gather quantitative and qualitative data, respectively. Through purposive sampling, 11 estate managers were selected, with eight of them responding to questionnaires. A comprehensive literature review was also conducted. Quantitative data were analyzed using the Statistical Package for Social Sciences (IBM SPSSTM) Version 20.0, while qualitative data were examined using Nvivo 12 Plus and in-depth analysis.FindingsThe study revealed that, maintenance in HLIs is only marginally considered in a holistic manner. In cases where it is “considered,” this is often by default rather than by design. This has led to maintenance challenges, such as the accelerated deterioration of components, the incompatibility of new maintenance materials with the old ones and difficulties in adapting spaces to meet emerging user requirements. The most frequently occurring words in the word cloud, “considered” and “maintenance”, underscore the necessity of adopting a holistic approach to maintenance management.Research limitations/implicationsThe study was confined to HLIs in the Dar es Salaam region.Practical implicationsThe findings from this study offer valuable insights for maintenance experts implementing holistic approaches in Tanzanian universities and colleges. Top management should focus on proper planning (including maintenance plans and budgets) and decision-making regarding maintenance management. Additionally, the Government of Tanzania may consider implementing policies requiring designing teams to adopt a holistic approach to maintenance before approving building permits.Originality/valueTo the best of the authors’ knowledge, this is the first study to examine whether universities and colleges consider maintenance from a holistic perspective.

Combination of LiDAR detection and green integral method for calculating irregular cross-section geometric properties of deteriorated components in timber historic buildings

Timber components in historic buildings are susceptible to deterioration due to the complex external environment. The loss of material in these components and changes in their cross-section geometry significantly impact the stability and load-bearing capacity of historic buildings. A portable LiDAR device is utilized to acquire the cross-section geometry of the deteriorated components. The irregular cross-section profiles are extracted using point cloud slicing and the Alpha-Shape algorithm. Geometric characteristics such as cross-section area, moment of inertia, and moment of resistance are calculated using Green's integral method. The performance of this method is evaluated by measuring eight groups of deteriorated components with different cross-section characteristics and comparing it with five traditional methods. The results demonstrate that the proposed method improves the calculation accuracy by 1%–21% relative to traditional methods, thereby enhancing reliability by 9%–54%. Additionally, it reduces manual calculation workload and human error, while promoting calculation efficiency. The method exhibits excellent applicability and high efficiency, with an error below 3% when compared to the true value. This method proves valuable in evaluating the extent of deterioration in historic timber components and provides essential data for preventive conservation and restoration of historic timber buildings.

Wind Rose Analysis of Temperature Variation with Sensor Implantation Technique for Wind Turbine

This study focuses on analysing the impact of seasonal variations in heat on different parts of a "wind energy system," serving as a representative mechanical system. The proposed methodology utilizes wind rose analysis, offering a straightforward means to assess heat transfer effects, applicable to any mechanical system comprising numerous small heat-dissipating components. Furthermore, this work elucidates the correlation between mechanical component performance and heat dissipation impact, providing breakdown alerts for various wind turbine components. Additionally, it analyses the influence of mechanical part temperatures on energy generation, highlighting how high temperatures can indicate component deterioration, such as bearing damage. Notably, the study focuses on wind speeds ranging from 10 to 15 m/s, a typical operational range for wind turbines. By employing wind rose charts and real-time readings, the graded heat dissipating potential of mechanical parts under various wind velocities and weather conditions is determined. Moreover, the study emphasizes the significance of heat transfer analysis in optimizing wind turbine performance, demonstrating how temperature differentials between mechanical components and the environment, along with increased surface area, affect heat transfer. The proposed analysis underscores the importance of considering heat's impact on each mechanical component in tandem with seasonal environmental temperature fluctuations. The wind rose methodology, integrated with sensor implantation, emerges as a cost-effective tool for studying -level heat variances in mechanical systems, enabling the development of heat profiles for future turbine designs and computational fluid dynamics (CFD) analyses. As heat transfer coefficient increases the wind turbine performance decrease. The heat transfer coefficient decreases 14.28% from rainy to winter season and 42.85% from winter to summer season. The wind rose analysis provides valuable insights into wind patterns and characteristics at a specific location, which can inform decision-making in various fields such as energy, construction, environmental management, and safety planning. As the turbine temperature increases the wind velocity decreases. Here it decreases 28 % from rainy to winter season.

Frozen dough steamed products: Deterioration mechanism, processing technology, and improvement strategies.

Fresh dough products lead to instability in product quality, high production costs, and more production time, which seriously affects the industrial production of the food industry. The frozen dough technology mitigates the problems of short shelf-life and easy deterioration of quality during storage and transportation. It has shown a series of advantages in large-scale industrialization, high-quality standardization, and chain operation. However, the further development of frozen dough is restricted by the deterioration of the main components (gluten, starch, and yeast) caused by freezing. This review summarizes the main production process of frozen steamed bread and buns, and the deterioration reasons for the main component of frozen dough. The improvement mechanisms of raw ingredients, processing technology, processing equipment, and additives on frozen dough quality were analyzed from the perspective of improving gluten network integrity and yeast freeze tolerance. From prefermented frozen raw to steamed products without thawing has become the preferred production process to improve production efficiency. Wheat flour mixed with other flour can maintain the gluten network continuity of frozen dough. The freeze tolerance of yeast was improved by treatment with yeast suspension, yeast cell encapsulation, screening hybridization, and genetic engineering. Process optimization and new technology-assisted fermentation and freezing effectively reduce freezing damage. Various additives improve the freeze resistance of the gluten-starch matrix by promoting protein cross-linking and inhibiting water migration. In addition, ice structural proteins and ice nucleating agents have been proven to change the growth morphology and formation temperature of ice crystals. More new technologies and additive synergies need to be further explored.

A novel dual-split layout for transcritical CO2 power cycle adapted to variable heat sources

Transcritical CO2 power cycle is widely used as the bottom cycle of natural gas engine to recover waste heat. However, owing to the large variation in waste heat sources caused by changes in engine operating conditions, the adaptability of the CO2 power cycle is poor, reflected in severe performance deterioration in thermal match, components and system power output. Hence, to improve the adaptability of the CO2 power cycle to wide-range fluctuation in heat sources, a novel dual-split configuration is proposed in this paper. The freedom of regulation is effectively enhanced by the supplementary split branches, and the mass flow rate through different heat exchangers can be actively adjusted with high flexibility. Furthermore, off-design performance models and a calculation procedure are built to present the off-design performance of the different cycles under the engine operational profile. The results indicate that the proposed configuration can improves the adaptability of the CO2 cycle to fluctuating heat sources effectively. Specifically, for all engine operational conditions, the invalidated operating region was contracted from eight to four points, with the engine coolant and exhaust gas utilisation rates exceeding 90 % and 97.4 % respectively. In addition, under low engine operating conditions, the cycle pressure ratio and mass flow rate were maintained at relatively high values, contributing to enhanced pump and turbine efficiencies. The maximum net power output increased by 8.3 kW, and the minimum brake-specific fuel consumption decreased by 16.9 %.

Effect of advancing age on event-related potentials (P300) measures

BackgroundAging has been defined as a persistent deterioration in the age-specific fitness components of an organism, attributed to internal physiological degeneration. Cognitive abilities, encompassing attention, memory, executive cognitive functions, language, and visuospatial capacities, are distinctive domains affected by aging. Numerous studies have documented measurable effects on these cognitive domains, indicating a discernible decline in their functionality with advancing age. Cognitive impairment often unfolds insidiously, remaining clinically silent for extended periods. Age, as a critical factor, exerts a notable influence on P300 measures.ResultSpearman rank correlation was calculated between age and P300 measures. In group 1A (age range of 10–20 years), we found a strong positive correlation between age and amplitude of P300 (r = 0.96, p < 0.001), while a weak correlation was found between latency and age. In group IB (age range: 21–40 years), a moderate negative correlation (r = − 0.43, p < 0.05) was found between age and amplitude of P300, while a strong positive correlation (r = 0.87, p < 0.001) was obtained between age and latency. In group 2A (age: 41–60 years), it was found that amplitude has a strong negative correlation (r = − 0.97, p < 0.001) with age, while latency has a strong positive correlation (r = 0.89, p < 0.001). In group 2B (age: 61–80 years), it was found that amplitude has a strong negative correlation (r = − 0.93, p < 0.001) with age, while latency has a strong positive correlation (r = 0.95, p < 0.001).ConclusionIn this study, it is concluded that amplitude of P300 decreases and latency increases with increasing age.

Investigation of the time-dependent bearing capacities of concrete structures in different environments considering climate change

The escalating trend of emissions of greenhouse gases, including CO2, prompts significant modifications in climate variables, such as temperature and relative humidity (RH). For concrete civil infrastructures, the carbonation and chlorination corrosion processes are sensitive to changes in climate variables. The focus of this study is to evaluate the time-sensitive deterioration of concrete components in different corrosion environments with consideration of large uncertainties of climate change. Future projections for atmospheric CO2, temperature, and RH until the end of the twenty first century are examined. By implementing an aging corrosion model that incorporates climate change, the study observes that under the SSP5-8.5 emission scenario, the average carbonation depth for the RC structures in the general atmospheric environment increases by 58.7%. Furthermore, the chlorination corrosion rate in marine environments nearly doubles that under aging conditions alone. By 2100, corrosion-affected RC beams in the SSP5-8.5 scenario will lose 9.5 and 29.2% of their flexural capacity, respectively. Moreover, under carbonation and chlorination environments, the beams will face an additional loss of 20.7 and 27.6% in shear capacity, respectively. In performing the above calculations, we have considered the uncertainty prediction of climate change and the uncertainty analysis of the influence of model parameters and material variability.

The deterioration of microstructure and biochemical components in cancellous bone characterizing by the photoacoustic microscopy imaging

Abstract Background/Objective: Osteoporosis is mainly characterized by a deterioration of microstructure and a loss of biochemical components in bone tissues. Developing an imaging technique for measuring bone tissue microstructure and the biochemical components is of great significance for the early diagnosis of osteoporosis. Photoacoustic microscopy (PAM) has the advantage of high optical resolution and the potential to diagnose osteoporosis. In this study, we investigated the feasibility of the photoacoustic microscopy (PAM) technique for bone tissue imaging, and the deterioration of microstructure and biochemical components in cancellous bone was characterized by the PAM. Statement of Contribution/Methods: We performed the optical-resolution photoacoustic microscopy (OR-PAM) for bone tissue imaging and the trabecular microstructure and hydroxyapatite (HAP) were degraded by immersion in JYBL-I solution. The PAM imaging method was developed for the measurement of the surface and subsurface of cancellous bone with a high resolution. Specifically, a 532 nm pulse laser was used to excite the PA signal from the bone. The PA signal sampling frequency was 80 MHz. A motor rotated a 15 MHz central frequency transducer to receive 1000 × 1000 × 250 points data. The envelope of the signal was obtained using the Hilbert transform for reconstruction. Then, the JYBL-I solution was used to reduce the HAP component in the bone. The PAM imaging was performed after different immersion times, (i.e., at 0, 5, and 10 mins). In the PAM measurement of the cancellous bone, the imaging area was a cylinder with an 8 mm diameter and an 8 μm/pixel resolution. Results/Discussion: The results showed that the trabecular microstructure could be imaged with a relatively high quality using the PAM technique. With the different extent of HAP degradation by immersion in JYBL-I solution, some trabecular bone disappeared corresponding with PA signals decreased significantly in amplitude. Conclusion: These results indicate that the PA technique has potential application in the characterization of bone microstructure and biochemical components with a high resolution.

Effect of barley yellow dwarf virus (BYDV) on barley: A precise assessment of reductions in yield components under variable disease severities.

Understanding the effects of barley yellow dwarf virus (BYDV) on crop agronomic traits and yield performance helps breeders balance their selection criteria and farmers decide if pesticides should be applied to control aphids that distribute the virus. To precisely assess the deterioration of different agronomic traits and yield components caused by different levels of BYDV infection, seeds of a BYDV-sensitive barley variety cv. RGT Planet were space sown in a field plot with 10 cm between seeds and 20 cm between rows under two consecutive years. When BYDV symptoms were shown, plants with different levels (0 - 5) of BYDV infection were tagged. For accurate comparisons, the neighbouring non/less-infected plants were also tagged. At maturity, different agronomic traits and yield components were measured on those tagged plants. Results showed a strong linear correlation between BYDV severity and the performance of agronomic traits and yield components. The yield reductions ranged from 30% for the least affected (score of 1) to 90% for the severely affected (score of 5). Our research confirmed previous findings that BYDV seriously affects crop yield and the prediction of yield loss due to BYDV infection should use the percentage of plants with different BYDV symptoms.

Improving seismic performance for inclined historical building by using external protection structure: Case study of Yingxian wooden pagoda, China

Historical wooden buildings constitute a significant segment of the architectural heritage worldwide. However, these structures are susceptible to component deterioration and structural inclination, potential collapse due to material degradation and the impact of external loads. The fundamental objective in conserving these historical wooden buildings is to safeguard them from such catastrophic failures, thereby preserving their intrinsic value and extending their longevity. To address this issue, a scientific control method based on the principle of minimum intervention has been proposed, termed the “zero-interference method”. This approach is designed to mitigate the progression of structural inclination and enhance the seismic resilience of ancient wooden structures without imposing any disruptive influences. The ancient wooden building is surrounded by an external protection structure (EPS) that is connected to the inclined part. This study uses the FE model of the Yingxian wooden pagoda in China to analyze the structural responses in both pre- and post-reinforcement, validating the effectiveness of the method. Additionally, the parameters of the EPS are discussed. The results reveal that the zero-interference method can effectively mitigate the progression of structural inclination and reduce the seismic responses of the wooden pagoda. The maximum reduction of story drift can reach over 50 %. The wooden pagoda is connected to an EPSwith concentrically braced support by using BRBs, improving the seismic performance. Notably, this study offers a valuable contribution to the field, presenting a methodological framework for augmenting the structural rigidity and curtailing displacement in historical wooden buildings.

Gluing of thermally modified silver fir wood planed by horizontal milling machine

This study was conducted to provide information regarding the quality of gluing of Silver fir wood (Abies alba Mill.) planed at different feed speeds after thermal modification. Four groups of sixteen air-dried fir samples were prepared. Three groups were thermally modified at different temperatures (160°C, 190°C, and 220°C) for 3 hours. The processes that followed included planning with two feed speeds (half of the samples at 3m/min and the other half at 10 m/min), the gluing, and finally, conducting mechanical tests to assess shear strength and wood failure. The gluing shear strength underwent a progressive decrease with increasing modification temperature for both feed speeds, with reductions ranging from 1.37% to 14.63% compared to natural wood. Wood failure did not show a linear relationship, with a decrease at 160°C but an increase at higher temperatures compared to natural wood. The feed speed had a significant effect on gluing shear strength, with higher feed speed resulting in decreased strength for natural wood but increased strength for thermally modified wood. Thermal modification of fir wood at temperatures of 220°C had a detrimental effect on the gluing shear strength and wood failure. This was caused by the deterioration of wood components and alterations in mechanical properties. The results of this study offer significant knowledge for improving the gluing process and establishing appropriate parameters for thermally modified fir wood. This type of wood has potential uses in the wood sector, specifically in the manufacturing of engineered wood products

Aircraft engine dust ingestion at global airports

Abstract. Atmospheric mineral dust aerosol constitutes a threat to aircraft engines from deterioration of internal components. Here we fulfil an overdue need to quantify engine dust ingestion at airports worldwide. The vertical distribution of dust is of key importance since ascent/descent rates and engine power both vary with altitude and affect dust ingestion. We use representative jet engine power profile information combined with vertically and seasonally varying dust concentrations to calculate the “dust dose” ingested by an engine over a single ascent or descent. Using the Copernicus Atmosphere Monitoring Service (CAMS) model reanalysis, we calculate climatological and seasonal dust dose at 10 airports for 2003–2019. Dust doses are mostly largest in Northern Hemisphere summer for descent, with the largest at Delhi in June–August (JJA; 6.6 g) followed by Niamey in March–May (MAM; 4.7 g) and Dubai in JJA (4.3 g). Holding patterns at altitudes coincident with peak dust concentrations can lead to substantial quantities of dust ingestion, resulting in a larger dose than the take-off, climb, and taxi phases. We compare dust dose calculated from CAMS to spaceborne lidar observations from two dust datasets derived from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP). In general, seasonal and spatial patterns are similar between CAMS and CALIOP, though large variations in dose magnitude are found, with CAMS producing lower doses by a factor of 1.9 to 2.8, particularly when peak dust concentration is very close to the surface. We show that mitigating action to reduce engine dust damage could be achieved, firstly by moving arrivals and departures to after sunset and secondly by altering the altitude of the holding pattern away from that of the local dust peak altitude, reducing dust dose by up to 44 % and 41 % respectively. We suggest that a likely low bias of dust concentration in the CAMS reanalysis should be considered by aviation stakeholders when estimating dust-induced engine wear.

RTV/GO-SiO2 anti-corrosion nanocomposite coating

Corrosion stands out as a leading factor contributing to the deterioration of industrial components, particularly in equipment utilized for oil and gas transmission and processing. Room temperature vulcanized silicone rubber (RTV) emerges as a promising solution for corrosion prevention due to its notable features including high hydrophobicity, adhesion, and thermal stability. This study focuses on enhancing anti-corrosion properties by applying coatings of RTV polymer with graphene oxide (GO) sheets (RTV-GO) or GO decorated with silicon oxide (RTV/GO-SiO2) onto X60 steel substrates. The investigation delves into the microstructure of the coating, surface hydrophobicity, adhesion to the substrate, and its efficacy in corrosion protection. Various techniques such as X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) were employed to analyze the nanocomposites. Furthermore, corrosion resistance was evaluated through open circuit potential analysis, potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray testing. Results indicate that incorporating GO and hybrid GO-SiO2 into the RTV polymer matrix not only enhances the interface strength between the coating and steel substrate but also boosts corrosion resistance by up to 10-fold compared to uncoated substrates.

Early-Detection of EVA Encapsulant Degradation in PV Modules Based on Vibration Frequency Analysis

In engineering applications, the frequency analysis represents a first and practical step to collect relevant parameters for structural and mechanical diagnostics. Any possible material / component degradation and deterioration can be prematurely detected by frequency modifications that exceed a certain alert value. In this paper, the attention is given to the dynamic mechanical analysis of commercial photovoltaic (PV) modules, in which the solar cells are typically encapsulated in thin viscoelastic interlayers made of Ethylene-Vinyl Acetate (EVA), which are primarily responsible for the load-bearing capacity of the sandwich PV system. As a major effect of ageing, ambient conditions, non-uniform / cyclic thermal gradients, humidity and even extreme mechanical / thermal loads, the rigidity of these films can largely modify and decrease, thus possibly affecting the mechanical capacity of the PV module, and even exposing the solar cells to fault. Knowledge of the effective bonding level is an important step for diagnostic purposes. In this regard, the present study is based on a preliminary but extensive parametric Finite Element (FE) numerical investigation of full-scale commercial PV modules of typical use in buildings. The attention is given – for PV module arrangements of technical interest – to the effect of EVA stiffness in terms of vibration modes and especially frequency sensitivity. As shown, when compared to newly installed PV modules, any kind of stiffness decrease is associated to major frequency modifications for the composite system, and in the worst configuration, such a frequency scatter can decrease down to -40% the original condition. Such a marked stiffness decrease would be implicitly associated to a weak mechanical performance of the sandwich section, with major stress peaks and deflections in the PV system, even under ordinary loads. The presented results, in this sense, suggest that major consequences can be prevented and minimized by monitoring the vibration frequency of PV modules.

Non-destructive vibration-based monitoring analysis of PV modules with encapsulant degradation by frequency change

In engineering applications, the frequency analysis represents a first and practical step to collect relevant parameters for structural and mechanical diagnostics. Any possible material / component degradation and deterioration can be prematurely detected by frequency modifications that exceed a certain alert value. In this paper, the attention is given to the dynamic mechanical analysis of commercial photovoltaic (PV) modules, in which the solar cells are typically encapsulated in thin viscoelastic interlayers made of Ethylene-Vinyl Acetate (EVA), which are primarily responsible for the load-bearing capacity of the sandwich PV system. As a major effect of ageing, ambient conditions, non-uniform / cyclic thermal gradients, humidity and even extreme mechanical / thermal loads, the rigidity of these films can largely modify and decrease, thus possibly affecting the mechanical capacity of the PV module, and even exposing the solar cells to fault. Knowledge of the effective bonding level is an important step for diagnostic purposes. In this regard, the present study is based on a preliminary non-destructive experimental analysis, and on an extensive parametric Finite Element (FE) numerical investigation of full-scale commercial PV modules of typical use in buildings. The attention is given – for PV module arrangements of technical interest – to the effect of EVA stiffness in terms of vibration modes and frequency sensitivity. As shown, especially compared to newly installed PV modules, any kind of stiffness decrease is associated to major frequency modifications for the composite system, and in the worst configuration, such a frequency scatter can decrease down to −40% the original condition. Such a marked stiffness decrease would be implicitly associated to a weak mechanical performance of the sandwich section, with major stress peaks and deflections in the PV system, even under ordinary loads. The presented results, in this sense, suggest that major consequences can be prevented and minimized by monitoring the vibration frequency of PV modules.

Experimental study of the effects on performance of Francis turbine due to sediments in flow

Abstract The sediments in the flow cause deterioration of components of the hydraulic machinery and influence fundamental properties such as density and viscosity of the flowing fluid. Earlier researchers have demonstrated the influence of sediment-laden flow on the performance of pumps, but such investigations have not been performed for the Francis turbine. This research focused on the effects of sediment-laden flow on the performance of a Francis turbine. Hydropower Research Centre for Himalayan Region (HRCHR) had a laboratory facility especially designed to conduct tests on Francis Turbines with sediments in the flow. The test rig was a closed-loop type and had provisions for mixing sediments with water and maintaining a uniform sediment concentration throughout the circuit. The performance of a 2 kW Francis turbine was tested at three different GV (Guide Vane) angles for different load conditions with and without sediment in the flow. The results showed that there was no change in maximum efficiency in the case of a smaller GV opening, whereas the maximum efficiency in the case of sediment water was reduced for a larger GV opening. Meanwhile, Sediment particles did not affect the head under the same discharge, whereas output power decreased slightly for sediment-laden conditions.

A critical review on the effect of various sustainable reinforcements on armor grade aluminum alloys

To deflect projectiles with kinetic energy by blunting them upon impact, armor with an exceptionally hard surface is required.In order to absorb and disperse the projectile's kinetic energy, the next material needs to be exceedingly tough and have a high work of fracture; hence, it needs to be metallic. To maximize the strength to weight ratio, it must also be composed of a versatile material, such as ceramic. Thus, the application requires a range of qualities, ranging from ceramic to metallic. Aluminum alloys (AAs) are sought-after materials for a variety of engineering and defense uses owing to their excellent low-temperature characteristics, good specific strength, and acceptable corrosion resistance. The main issues with AAs are poor heat tolerance and wear resistance, which makes them unsuitable for military applications owing to their heavy weight, which can exacerbate the deterioration of mechanical components and impair vehicle maneuverability and speed. This paper offers the possibility of modifying the properties of monolithic aluminum materials by adding reinforcement and replacing conventional particulates with low-cost wastes derived from agriculture and industry, which are rich in oxides and other debris, such as fly ash (FA) and rice husk ash (RHA). The result is the development of hybrid aluminum metal matrix composites, or HAMMCs, which combine the best features of both metals with a variety of sustainable inorganic and organic reinforcements that can enhance the mechanical and tribological performances by 40–62 % in comparison to the basic matrix. So, they can be tailored to meet the needs that make their performance superior compared to unreinforced AAs. Through a review of existing literature, this paper will provide an outline of the effect of various kinds of reinforcements on armor-grade aluminum alloys.

Charge pattern detection through electrostatic array sensing

As reported in previous work, electrostatic charge induced by contact potential difference (CPD) arising from oxidational wear can be detected by electrostatic button sensors. However, to detect signs of localised wear and to investigate the mechanisms involved, the charge distribution on worn regions needs to be measured. Therefore, this paper investigates the evolution of surface charge during wear processes, its interplay with friction, and the correlation between charge distribution and surface chemistry. An electrostatic bar sensor and an array sensor were initially calibrated using CPD patterns generated by dissimilar metal inserts in steel plates. After appropriate signal processing, the sensor outputs exhibited excellent agreement with the electric field strength modelled using COMSOL Multiphysics. Subsequently, the bar sensor was integrated into a reciprocating tribometer for in-situ detection of oxidational wear of steel-on-steel rubbing contacts, followed by ex-situ array sensing of worn regions. Positive picocoulomb-level surface charge during the evolution of oxidational wear were successfully detected by the bar sensor and were found to correlate to changes in friction coefficient. The array sensor effectively mapped the distribution of surface charge. EDS mapping suggested patchy formation of Fe3O4 layers over the worn areas, and these patches correlated to the surface charge map. Increased electrostatic charge levels were associated with higher concentrations of oxidational wear. Therefore, this paper evaluates the potential of electrostatic array sensors to spatially resolve surface charge patterns induced by surface chemistry transformations, which enables the monitoring of localised and smaller-scaled machinery component deterioration and provides additional information for machinery diagnosis.

Research on the dynamic characterization and detection of refrigerant leakage in multi-connected air-conditioning system

Microleakage, frequently arising from aging or inadequate installation, significantly affects the performance and longevity of refrigeration systems. The presence of microleakages, while not precipitating an immediate system failure, results in the gradual deterioration of components and escalates the energy consumption within buildings. Nonetheless, identifying these microleakages through conventional methodologies poses significant challenges. This study introduced a dynamic model specifically designed for detecting microleakages in multi-connected air conditioning systems, particularly in variable refrigerant volume (VRV) systems. Experiments performed under standard operating conditions were integral to enhancing the model's accuracy and furthering its validation. The model integrates the structural and thermophysical attributes of various components, thereby addressing the issues related to data acquisition in standard VRV during instances of microleakage. The analysis of dynamic parameter shifts during system microleakage led to the generation of a comprehensive dataset, which proves invaluable for machine learning and fault detection tasks. A detection and alerting protocol is written in Python presented, chiefly anchored on pressure deviations, augmented by temperature shifts and refrigeration and heating capacities, all represented as virtual volumetric alterations. The findings indicate a delayed transmission of the leakage signal from the leakage point to the system's detection points, with the maximal delay occurring at the compressor inlet under refrigeration conditions, amounting to 239 s. Evaluation under prescribed conditions indicated variances in pressure, temperature, and refrigeration and heating capacities by up to 13.2 %, thereby validating the model's precision and reliability. The program, tested with the generated dataset, accurately identifies leakage states within an average time of 20 min. This model and detection strategy provide a new perspective on microleakage in refrigeration systems, suggesting a robust strategy for their sustained and secure operation.