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This paper presents a tracking method to improve the performance of switched reluctance generators in areas with low wind speeds. The main contribution of this work is the proposal of an advanced control system that employs dynamic tracking techniques to optimize the energy efficiency and response of the switched reluctance generators under various operating conditions. The methodology encompasses the construction of the generator, the development of a wind turbine model, and the coupling of the turbine with the switched reluctance generators. Simulations are conducted using real wind speed data to evaluate the use of switched reluctance generators in wind energy generation. The performance of the switched reluctance generators is improved by applying a tracking technique that operates on the converter's turn‐off angle, which controls the generator's switching. The tracking and optimization techniques implemented in this work maximize the performance of switched reluctance generators in wind energy generation, both in standalone and self‐excited operations. The results demonstrate that satisfactory wind energy generation can be achieved using the SRG, with wind speeds of 5.40 m/s producing approximately 1.5 kW without optimization and around 1.65 kW with optimization, reaching about 70% efficiency with a custom‐built generator. This makes the technology viable for regions characterized by low wind speeds. [ABSTRACT FROM AUTHOR]

Probabilistic evaluation of the internal pressure capacity before excessive leakage is essential for ensuring preemptive response in case of a severe accident in a prestressed concrete containment vessel (PCCV) subjected to internal pressure in a nuclear power plant. Therefore, in this study, we conducted a fragility analysis to evaluate the probabilistic internal pressure capacity for damage states before excessive leakage. Three damage states were classified, and a finite element (FE) model was developed based on the experimental test results of a 1 : 4 scale PCCV under the overpressurization condition at Sandia National Laboratory. The three damage states were determined as the onset of inelastic behavior (DS1), onset of leakage (DS2), and excessive leakage (DS3). Fragility analysis was performed using a validated FE model to consider uncertainties in material properties and prestressing force. The Latin hypercube sampling method was used to perform uncertainty quantification, and normality tests verified that the samples exhibited normal distributions. The internal pressure capacity variability in DS1 and DS2 was higher than that in DS3. DS1 is the point at which the compressive deformation caused by the prestressing force was converted into tensile deformation because of the increase in the internal pressure, which resulted in tensile concrete cracking. Furthermore, DS2 is the state in which localized damage of the liner occurred and cracks in the concrete spread. Thus, the internal pressure capacity for DS1 and DS2 exhibited high variability because of the uncertainty of the prestressing force and material properties. Moreover, the median capabilities of DS1, DS2, and DS3 were ~1.85, 2.61, and 3.45 times the design pressure, respectively. Therefore, material and structural uncertainties in nuclear power plants should be appropriately considered, and a conservative assessment of the damage state before excessive leakage should be performed for preemptive response in the case of severe accidents. [ABSTRACT FROM AUTHOR]

In recent years, the implementation of Tier 5 emission regulations for tractors has compelled manufacturers to conduct new research. Additionally, the process of hybridization has impacted the agricultural vehicle industry. This study focuses on the design and implementation of an energy management strategy (EMS) for a diesel–electric hybrid electric agricultural vehicle, based on real‐time optimization. Tractor drive systems, including both conventional and hybrid options, were introduced. Simulations were performed to compare fuel consumption and CO2 emissions between the two types of tractors. The data shows that hybrid vehicles produce 8.93% less CO2 than conventional vehicles. Furthermore, the fuel consumption of the tractor decreased from 1,880.2 to 1,712.5 g/km under hybrid operating conditions. [ABSTRACT FROM AUTHOR]

This research looks into the domination of flow boiling on the efficiency and sustainability of refrigeration and air conditioning systems. Specifically, it focuses on the characteristics related with heat transfer of refrigerant R134a within both smooth and microfin tubes, each having 9.52 mm outer diameter. The features of microfin tube have distinct configuration with a 46° apex angle and a 22° helix angle, resulting in a surface area 1.62 times greater in comparison to smooth tube. Through a comprehensive experimental analysis, the study examines the influence of key parameters (mass flux; saturation temperature; heat flux; and average vapor quality) on heat transfer coefficients (HTCs). Notably, the HTC exhibits significant enhancements at mass flux of G = 125 kg m⁻2·s⁻1, encountering challenges related to dry‐out at elevated vapor quality levels. The results reveal that microfin tubes consistently outperform smooth tubes, exhibiting heat transfer coefficients up to 270% higher across various operational conditions. Furthermore, the experimental data are rigorously validated through computation analysis with authentic flow boiling heat transfer models, demonstrating strong agreement. [ABSTRACT FROM AUTHOR]

The uncertainty and unreliability in the probabilistic seismic demand models (PSDMs) can be addressed in the framework of performance‐based earthquake engineering (PBEE). Some characteristics have been introduced and extensively investigated in the earthquake engineering literature for appropriateness (i.e., optimality) of various intensity measures, such as efficiency, effectiveness, sufficiency, practicality, and hazard computability. The reliability of the intensity measures can also be considered as another important criterion for intensity measure (IM) selection, which has not been investigated extensively. In this paper, a framework has been developed and implemented to investigate the reliability of various intensity measures alongside the number of adopted earthquake records. In this regard, the inverse of the mean coefficient of variation (IMCV), which is detected to be in a direct and linear relationship with the number of earthquake records, is adopted as the main criterion to compare the reliability of ground motion intensity measures. A simple relation has been proposed and calibrated for the studied IMs that provide the required number of earthquake records to satisfy an intended level of reliability. As a case study, a significant number of recorded ground motions at Zagros and non‐Zagros zones (two major seismic regions in Iran) with rock and soil conditions are selected, and the most reliable ground motion intensity measure is introduced at various seismic regions and soil types by exploiting the developed framework and the proposed relationship. [ABSTRACT FROM AUTHOR]

Velocity pulse with strong energy input is the significant feature of near-fault ground motions. Bridges close to or passing across seismic faults may suffer from higher failure risk, which is inseparable from the influence of velocity pulse. This study aims to evaluate the nonlinear response characteristics of bridge structures under various near-fault ground motion conditions. A typical isolated continuous girder bridge is adopted, and two corresponding finite element models, i.e., considering and ignoring the heating effect of lead core bearings (LRBs), are established based on the OpenSees platform. Then, a total of 40 near-fault ground motion records are selected, and the pulses are extracted. Both the energy-based and deformation-based seismic responses are captured and compared to reveal the differences for the isolated bridge subjected to the original waves and the extracted pulses. The results highlight that the accuracy of the seismic evaluation based on the extracted pulses strongly depends on the precondition that the pulse period is close to the fundamental period of the isolated bridge. Hence, inputting the extracted pulses for predicting the in-elastic seismic response of isolated bridges locating at near-fault region is not an adequate replacement for those original waves of near-fault ground motions. In addition, the heating effect of LRBs will be magnified for the seismic response of isolated bridges subjected to the extracted pulses, and it will mainly affect the seismic responses of bearings and piers, i.e., the former increases and the latter decreases. [ABSTRACT FROM AUTHOR]

As a critical component of the energy sector, the high‐temperature gas‐cooled reactor (HTR) system plays an important role on the road to carbon neutrality. As a flagship of the safety analysis codes, the HTR code package (HCP) has been developed to provide a comprehensive modeling and simulation platform of the HTR system under operational and accidental conditions, especially for pebble bed reactors. A variety of individual legacy HTR computer codes were integrated into a consistent code package using flexible and efficient programing techniques and standards, and the know‐how gained over decades in HTR safety studies was preserved. This paper gives a state‐of‐the‐art overview in HTR studies and presents the new flexible curtain‐based control rod system that has been recently implemented. This method involves flexible manipulation of isotope concentrations and utilizes C++ object‐oriented programing principles while incorporating the legacy codes. Comparative analyses with established codes such as Serpent and ATHLET underscore the precision and reliability of the HCP, thereby enhancing its applicability in HTR design and safety evaluations. Finally, the paper outlines prospective avenues for further advancing the HCP, underscoring its evolving role in shaping the future of HTR development and analysis. [ABSTRACT FROM AUTHOR]

The economic viability of sand in the construction industry depends on its size, shape, shell content, etc. It is imperative to understand the proportions of sand subclasses and shell content in sand sediment while planning exploration and mining. The existing sediment classifications (Particle Size Distribution Classifications) based on Sand‐Silt‐Clay (SSC) or Gravel‐Sand‐Mud (GSM) of different authors have not addressed these issues and it remains as a gap area till now. Hence, a new physicochemical classification ("Sand Types") of sand that falls in the "sand fields" of SSC plots pertaining to two famous authors is being proposed. The freeware program "Sand Types" developed for plotting types of sand in the ternary diagram helps to plot the data in a triangular diagram and identify their physicochemical properties. The program also offers conditional strings that are prepared based on the proposed classification and are coupled with that of SSC classifications. These conditional strings work in ArcGIS10.x platform for the preparation of sediment distribution maps with meaningful information. This would enable construction industry/end‐users to plan and execute detailed exploration and mining programs at great ease. [ABSTRACT FROM AUTHOR]

Pallet roller conveyors are designed to facilitate the movement of pallets along a conveyor system, which consists of a series of rollers mounted on a frame. In industries such as manufacturing, logistics, and distribution, pallet roller conveyors are widely used where the efficient movement of palletized loads is crucial for productivity and warehouse optimization. This study optimized pallet roller conveyors in the case of the number of critical conveyor parts. To verify the existing design, pallet conveyor parts were first modeled geometrically, and then, structural analysis was carried out. To reduce the overall weight and save a significant amount of materials, the existing pallet conveyor system is redesigned by designing the critical parts. A structural analysis was carried out, followed by a comparison of the existing pallet roller conveyor design and the optimized one. The calculated maximum deflection and safety factor remained within acceptable limits, ensuring the safety of the optimized design. This minimizes the overall weight and cost of the pallet conveyor system as well as saving a considerable amount of materials. [ABSTRACT FROM AUTHOR]

To address the shortcomings of traditional prestressed concrete girders, a new hybrid beam element, the Hybrid Deck Bulb Tee (HDBT) is proposed. The HDBT utilizes staged fabrication. First, the bottom flange is cast with Ultra-high Performance Concrete (UHPC) and prestressed prior to casting the web and top flange with High-Performance Concrete (HPC). The purpose of this study is to analytically evaluate the structural performance of HDBT beams for bridge structures. Multiple HDBT bridges were designed following the state-of-the-art criteria in regard to UHPC bridge design. The performance was evaluated using the following criteria: 1) the deflections under live load and dead load, 2) design checks for temporary stresses before losses, 3) stresses at serviceability limit states after losses, and 4) demand-to-capacity ratios under the American Association of State Highway and Transportation Officials (AASHTO) Strength I load combination. To obtain more refined results for the serviceability limit state, the bridges were modeled using a commercial finite element software. The model captured the time dependent material properties such as strength gain, creep, and shrinkage, as well as the stages of fabrication. The analysis demonstrates that the innovative design and fabrication processes of HDBTs are capable of resolving the current limitations of prestressed concrete elements. [ABSTRACT FROM AUTHOR]