This review explores the oxidation behavior of titanium carbide (TiC) and titanium nitride (TiN) coatings deposited by chemical vapor deposition, with a focus on their industrial applications as wear-resistant coatings for cutting tools. It examines effect of process parameters -such as temperature, pressure, precursor composition, and substrate preparation-on formation and performance of TiC/TiN coatings. The review evaluates the microstructural characteristics of these coatings, including crystal structure, using X-ray diffraction analysis. Also, the review covers the mechanical properties, such as hardness, wear resistance, and adhesion strength. Additionally, the review covers the thermal stability of TiC/TiN coatings, emphasizing their ability to maintain structural integrity at high temperatures, which is essential for the performance of cutting tools and other industrial components. A major focus is the oxidation behavior of TiC/TiN coatings, including the impact of coating composition, deposition methods, and environmental conditions. The review details oxidation kinetics and mechanisms, revealing various stages of oxidation at different temperatures. It also examines oxide scale morphology and its effect on coating properties. Finally, this review reveals the importance of alloying elements, like silicon, in improving oxidation resistance. Composite coatings such as TiSiN and TiSiCN are shown to offer better high-temperature stability compared to traditional TiN coatings. The effects of coating thickness and the benefits of multilayer coatings for enhanced oxidation resistance are also discussed.

The angle at which a photovoltaic (PV) panel is tilted has a significant impact on its performance, as it affects the amount of solar energy the panel can capture. This paper explores a new mathematical model, as well as simulation and experimental results, to determine the optimal tilt angle for PV panels. The optimal angle is determined by searching for the values that yielded the highest total solar radiation on the PV panel surface for a specific period, and this study introduces a new method to find the yearly optimal tilt angle for a fixed PV panel. The proposed model uses experimental data to simulate the performance of a fixed PV panel at different tilt angles and determine the angle that harvests the highest energy production. The results of the simulation model can be used to guide the installation and positioning of PV panels, allowing for more efficient energy production. Overall, the simulation model provides a valuable tool for optimizing the performance of fixed PV panels and increasing the use of renewable energy sources. The experimental site is located at Famagusta, Cyprus, and the ideal tilt angle for maximum solar radiation was found to be 27°, with a total solar radiation of approximately 2016.99 kWh/m². The simulation results were then compared to those of four different methods, and it was discovered that solar panels could be installed in that region at angles ranging from 21° to 32° in order to capture the maximum energy from solar radiation for a PV panel.

This study looks at the potential of waste calcium carbide (WCC) and wood ash (WA) as soil stabilizers to improve the engineering characteristics of subgrade soil. The investigation begins by characterizing the properties of the untreated soil, indicating a liquid limit of 24.6%, linear shrinkage of 7.6%, and a non-plastic nature due to the lack of a plastic limit. In addition, the soil composition comprises a mere 2% of small particles measuring less than 63 μm, while a substantial 74% of the particles fall within the range of 63 μm to 2 mm. The particle density of untreated soil is found to be 2.86, beyond the typical soil limitations. Subsequently, an investigation was conducted to examine the impact of WCC and WA on Atterberg limits, compaction characteristics, and California bearing ratio (CBR) values. The findings indicate that the incorporation of WCC and WA leads to a reduction in the liquid limit by a maximum of 18.70% and linear shrinkage by a maximum of 55.26%. Compaction properties show an increase in optimal water content and a minor decrease in maximum dry density. Importantly, CBR values significantly improved, with the soil treated with 6% WCC and WA demonstrating a CBR value of 26.9%, exceeding the subgrade acceptability requirement in road construction. This study highlights the potential of WCC and WA as cost-effective and sustainable soil stabilizers, particularly in areas where traditional stabilizing materials are limited. More research into optimization and long-term performance can help to realize the full potential of this novel method for soil stabilization.

Internet of Things (IoT) is to connect billions of devices and machines via Internet and to have a smart system. Sensors and devices in IoT environment are connected and communicated together. Connecting such a huge number of devices requires high level of security and privacy. A crucial characteristic of ubiquitous IoT devices is their limited resources. In recent times, a scheme for privacy-preserving machine authenticated key agreement scheme (PPMAKA) has been introduced for the IoT environment. It was argued that PPMAKA provides security and privacy at the same time including forward secrecy. Nevertheless, this paper will demonstrate that PPMAKA lacks forward secrecy, a crucial security, and privacy feature in the IoT environment. We use Cannetti and Krawzyck threat model for the detailed analysis of PPMAKA. Furthermore, we provide remarks for the future research as it is recommendable to design any security and privacy schemes over IoT environments with lightweight operation and communication property, authenticated key agreement with forward secrecy, anonymity, and unlinkability.

Premature failure of a subsystem can be critical for an industrial cyber-physical system (CPS). A digital twin (DT)-assisted predictive maintenance procedure can reduce the risk of costly unplanned maintenance. This study presents a generalized DT development framework for an electrical submersible pump (ESP) that can assist in predictive maintenance. The framework is applied on a single-phase ESP as a proof of concept. The maximum winding temperature of the selected ESP is simulated using a multiphysics simulation tool with transient electromagnetic and transient heat transfer solvers. The simulation parameters were refined using data captured through an ESP free-run experiment. Simulating the total energy loss in the ESP stator and rotor and the transfer of heat from the outer fluid domain facilitates a relationship between the measurable external temperature and the maximum temperature in the stator winding. Following a design of experiment approach, a series of simulations were run to establish a statistical model for the winding temperature in terms of the fluid temperature, the time duration a particular temperature was persistent, and the initial maximum stator winding temperature. As the instantaneous maximum stator winding temperature is related to the remaining useful lifetime, it was shown using a case study that the proposed framework can prognosticate the ESP failure, assisting effective decision-making for predictive maintenance of a CPS.

The paper focuses on the potential use of industrial wastes, which are fly ash (FA) and cement kiln dust (CKD), to stabilize expansive soils like black cotton (BC) soil for construction purposes. Although many soil stabilization methods exist, the placement of columns consisting of industrial wastes has yet to be tested. Knowing the pozzolanic action and mechanism between the waste product and the soil, this method of placing the industrial waste as a remedy should be trialled. Therefore, this paper proposes and investigates the placement of FA-CKD columns into the soil via a series of laboratory experiments using myriad mixtures and combinations of placement of such columns. The effect of molding water content and curing time on the BC soil’s consolidation and strength behavior was also assessed here. Through the experiments, it is found that the optimum mixture of FA-CKD for the columns is at 90–10%, respectively. This column mixture has been evidenced to improve the unconfined compressive strength of the soil significantly, where its performance improves with curing time. The highest strength improvement can be found at optimum moisture content, followed by wet of optimum and dry of optimum, respectively. By placing the columns in the soil with 4.5D spacing, better consolidation behavior with a reduced swelling potential of BC soil can be found. Based on the above findings, using FA-CKD columns can improve the BC soil’s engineering behavior, contributing to waste-to-wealth and sustainable soil stabilization approaches.

Despite the reduction in cost and schedule, and the improvement of quality and safety, the design-build (DB) method in China’s civil aviation infrastructure projects (CAIPs) has not been widely used and not reached the full value. To know what the development expectation gap is, it is necessary to determine the disparity in developmental prospects of the DB method in China’s CAIPs. To this end, this paper first conducted a survey to know what the development expectation is through 69 subjects working in CAIPs. After that, 25 cases data were collected to get the actual development of the DB in CAIPs. The key findings from the comparison between the expectation and actual development show that the design institutes play a leading role in the popular form of consortium in the DB mode, and the DB method is mainly used in CAIPs with small investment. In addition, this paper also analyzes how some causes contributed to the development gap and presents three strategic actions. This study not only shows the development status of the DB method in CAIPs but also presents the reasons contributing the development expectation gap, along with the potential strategic actions, which can be as a reference for scholars and practitioners.

The operating energy costs of buildings account for approximately 70–80% of the total costs throughout the entire life cycle of a building. From the moment putting the building into operation, it begins to consume energy, mechanical, electrical, and natural resources. In buildings, all construction and technical systems naturally degrade over time, both in terms of performance and in terms of efficiency, i.e., operating and maintenance building costs are rising, energy consumption is increasing, and microclimate quality is declining. As a solution to this issue, it is possible to consider building energy passport (BEP), as a tool to control the optimal building operation according to the indicators of the building passport and as an encouragement way of cities’ sustainability. The building passport by its energy efficiency (BEP) and rational use of material resources is a special document – a certificate that contains information about the geometric and technical parameters of the building, its functional purpose, design solutions, thermal characteristics, and energy performance. This paper discusses the current state of the building passportization process in Azerbaijan and analyzes the existing shortcomings. Categories and component parts of BEP, types and levels of building information and data, scheme of inputs and extractions data during the building life cycle, key tasks of BEP, and strategic actions for the successful development of BEP are given. Building energy efficiency rating classes is calculated, and the main procedures to enhance the energy efficiency class are given. The requirements for experts who carry out the buildings’ passportization are systematized.