Due to the increasing severity of global warming and climate change, more attention is being paid to environmental problems caused by human activities. Although energy saving and carbon reduction have become a global ambition, the implementation of energy-saving mechanisms remains limited. To address this, an adaptive smart energy-saving campus system is developed in this study to improve students’ electricity usage habits. In this system, the Internet of Things (IoT) with control interfaces is integrated to enhance convenience. Using expert system rules, the system regulates the operation of the IoT for the efficient energy-saving control of a classroom. Additionally, by incorporating a random forest classifier, the system learns users’ electricity usage habits to create a tailored energy-saving environment. Gamification is also introduced to create a reward system that stimulates users’ desire to achieve goals, thus promoting autonomous energy saving. An experiment was conducted on 62 students. In total, 59 out of 62 participants responded with a sampling error of ±2.8% at a 95% confidence level. The average system usability scale (SUS) score reached 84, surpassing the cross-industry average standard, indicating that the system is user-friendly. The average self-efficacy score for energy saving reached 4.28 (σ = 3). The system significantly impacted the participant’s motivation to enhance energy saving. The net promoter score (NPS) was 29. This indicated that, although users are generally satisfied with the system, there is still room for improvement.
Water mist enhances the sense of mystery with visual and sensory effects, depending on its atmospheric creation and varying mist heights. Key factors influencing this mystery are the combination of mist with plants, increased air humidity, and sound effects. We identified important elements in the landscape at different times of day: in the morning, plant combinations and terrain; during the day, humidity and obscuring effects; in the evening, imaginative space; and at night, mist with plants. It is necessary to enhance visual effects and terrain variation in mist design to offer guidelines for future exploration.
Rama Seshu K. V. Ganga, Ramu Inala, Chandra Sekhar Jowdula
et al.
Fused deposition modelling (FDM) is a widely used 3D printing technique known for its versatility across industries. However, achieving optimal strength, crucial for applications like the automotive and aerospace industries, remains a challenge. This study demonstrates the efficacy of metal-infused filaments in enhancing FDM’s strength and quality. By incorporating metal particles into polymer matrices, their mechanical properties are notably improved. PLA and metal-infill PLA (copper, silver) are tested, with silver PLA showing notably higher tensile strength and hardness. Considerations such as infill density and pattern are discussed for optimizing object strength. This work underscores the potential of metal-infused FDM printing for advancing manufacturing capabilities, especially for intricate, high-strength metal components.
Patients are generally sent to hospitals during emergencies and life-threatening conditions using ambulances. The health problems of patients become more serious when the treatment is delayed. If the vital signs of patients inside an ambulance or a treatment area sent to a hospital in real time, the odds of saving lives will improve considerably. The patient’s medical needs can be arranged by paramedics with the doctors’ instructions until their arrival at the hospital. Information from past vital signs can also be archived their medical history. The Internet of Things (IoT) is a paradigm that visualizes practically everything connected to the Internet. This opens access to a lot of tiny medical needs and emergency relief tools. As a proof of concept, a test model prototype was implemented using an IoT-enabled ambulatory vital sign sensor board and a remote hospital framework. The objective of the implementation of such a prototype blends IoT technology with healthcare services to provide a more efficient and patient-centred approach to monitoring and controlling health issues, particularly in instances when continuous remote monitoring is advantageous. The working of the proposed device was validated and the results were monitored for the health-related data collected during the testing period. This strategy promotes health monitoring in emergencies with eHealth Signals for medical assistance.
Julia Wilfling, George Havenith, Margherita Raccuglia
et al.
The appreciation of textile products highly depends on a satisfactory ‘feel’ in fabric-skin contact. The question arising is whether the haptic interpretation of a garment (by hand) is comparable to a feeling produced when it is donned or used in its intended application. Sports T-shirts made from three different fiber types (CO, PES I, PES II) were studied in a pre- and post-purchase scenario by exposing 20 female participants to a hand, a donning (pre-purchase) and running evaluation (post-purchase) in 22 °C and 50% relative humidity (RH). Objective measurements such as skin temperatures, heart rate, body sweat loss, and sweat absorption of the garments were recorded. Subjective data was collected during the fabric hand and the donning evaluation as well as within the running protocol after 5 min, 20 min, and 5 min of cool down. Perceptual responses to 12 hand-/skin-feel descriptors (e.g., rough, smooth) were rated on a scale from 0 (not at all) to 10 (completely) and a feeling of discomfort was given. No significant differences between a hand and a donning evaluation were found in the rating of the sensations. The hand evaluation provided sufficient information for a comfort response to garment wear. The pre- and post-purchase comparison found a significantly lower perception of the feeling of roughness whilst running with the CO shirt and smoothness during running in PES II. The stickiness and comfort perception increased significantly in the post-purchase wear trial. Hence, moisture on the skin provoked through running influences comfort characteristics as well as the perception on haptic cues in t-shirts. Especially surface related haptic characteristics e.g., roughness and smoothness, are reduced.
Textile bleaching, dyeing, printing, etc., Engineering machinery, tools, and implements
Iryna Krishchenko, Sergii Kravchenko, Eduard Manoilov
et al.
Plasmonic nanostructures with a high density of confined areas with high local electromagnetic fields (hot spots) are sine qua nonto increase the efficiency of surface-enhanced Raman spectroscopy (SERS). These nanostructures can be used both to identify biological molecules and to monitor photochemical reactions occurring on the metal surface. In this work, using the method of pulsed laser deposition, three-dimensional (3D) porous wedge-shaped arrays of gold nanoparticles (Au NPs) were obtained with structural parameters varying along the substrate, such as film thickness, porosity, nanoparticles size, and the distance between them. The resulting arrays were structures with a regularly changing density of hot spots along the substrate, in which the enhancement of the electromagnetic field strength is due to the geometric parameters of the nanostructure.By analyzing the evolution of fluorescence and Raman scattering of fluorescein molecules adsorbed on the surface of porous gold under illumination at 532 nm, the processes in the region of extreme values of the electromagnetic field of surface nanostructures was studied. A correlation has been established between the amplification of optical signals and the structural features of the surface. A correlation between SERS and fluorescence signals indicates the predominant contribution of hot spots to the electromagnetic amplification of optical signals. The observed time evolution of the fluorescence and SERS intensity of fluorescein can be explained by the combination of molecular photodegradation, the reconstruction of the hot spot architecture due to local heating, and potent relocation of analyte molecules outside the area of measurement owing to the effects of thermal gradients.
Numerical simulation was conducted in this study to calculate the agitating torque of the high viscosity Newtonian fluid by the explicit-MPS method using virtual boundary particles for the agitating container and the agitating flapper. At first, a calculation of the resting hydraulic pressure was carried out to confirm the pressure of fluid particles in the vicinity of the flapper. As a result, it was confirmed that the average of the pressure distribution of the fluid particles corresponded with a theoretical value of the resting hydraulic pressure. Considering this result, trial calculation of flapper agitating torque was calculated from the pressure of the fluid particles in the vicinity of the rotated flapper. The flapper agitating torque was calculated from the torque caused by the differential pressure between front and back faces of the flapper and the torque caused by the shear stress of the fluid particle near the flapper edges. From this calculation, stable agitating torques were obtained for each time step at each flapper speed, and consistent with the high viscous Newtonian fluid agitating test results which showed the linear relationship between the number of flapper speed and agitation torque. Furthermore, it was confirmed that the agitation torques were dominated by the torque caused by the pressure between the front and back faces of the flapper.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
So Takahashi, Masashi Ishikawa, Hideo Nishino
et al.
A non-destructive inspection technique using infrared thermography and ultrasound excitation (ultrasound-excited thermography method) was focused on in this study. Although this method is effective in the detection of closed defects, the standing waves are generated in the inspection object, and this causes periodic heat distribution in the non-defective area. Such standing wave heat distribution can lead to the misdetection of defects and result in a reduction in inspection capability. In this study, in order to suppress the influence of standing wave heat distribution, we examined a method to average thermal images obtained under different ultrasonic excitation conditions. The experimental results showed that averaging the thermal images obtained when exciting ultrasound at several different points was effective in suppressing the unwanted standing wave heat distributions.
Wakeel Shah, Sadia Muniza Faraz, Sana Arshad
et al.
The aim of this study is to boost the power conversion efficiency of a dye-sensitized solar cell (DSSC) by using the co-sensitization strategy with appropriate natural dyes extracted from pomegranate, beetroot and cranberry. The fabricated DSSCs were evaluated using current–voltage characteristics and UV-Vis spectroscopy. The co-sensitized DSSC with beetroot and cranberry showed higher short-circuit current density and power conversion efficiency than their individual dye-based DSSCs. This improvement in the performance is due to the lower aggregation of the dyes, broader absorption in the visible region and lower value of impedance. However, co-sensitized DSSCs of pomegranate with beetroot and cranberry did not show any improvement in performance.
The time-dependent elastoplastic deformation behavior, i.e. viscoplastic deformation behavior, is observed in solids and structures subjected to high temperature under monotonic and cyclic loadings. Then, the deformation analysis is required by incorporating the rigorous viscoplastic constitutive equations capable of describing cyclic loading behavior at high temperature. There are two types of viscoplastic models, i.e. the overstress model and the creep model. The former is pertinent as the mechanical deformation behavior is reduced to that of the ordinary elastoplastic constitutive equation in the quasi-static deformation process, but the latter is impertinent as it is irrelevant to the ordinary one. Unfortunately, however, the existing overstress model is incapable of describing the cyclic loading behavior because the interior of the yield surface is assumed to be a purely-elastic domain. On the other hand, the subloading-overstress model possesses the basic structure capable of describing the viscoplastic deformation behavior under cyclic loadings, but the applicability to the prediction of real material behavior has not been verified hitherto. The mechanical tests of the spheroidal graphite cast iron under monotonic and cyclic loadings at high temperature and various strain rates are performed. The simulations of the test results are performed by the subloading-overstress model and the existing overstress model. Consequently, it is verified that the subloading-overstress model is capable of simulating the test results accurately.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
Mohammed R. Gharkan, Ahmed H. Ali, Hossam E. Salman
et al.
Although low mechanical properties of Acrylic resin, it is the most popular used substance as based denture materials. This drawback could be treated through adding reinforcing phase. In this work washing and non-washing banana peels as kind of natural fibers with different weight fractions, (5, 10, 15 and 20) % wt. and standared Acrylic, for compartion purpose, are used to prepare composite specimens by modeling method on order to study possibility of reinforcing cold-curing acrylic resin by banana peels. Peels had been dried, crashed, and washed by distillation water before using in the work. Unwashed peels also used for comparing purpose. Hardness, impact, and tendsile tests were performed to evaluate the development in mechanical properties of the prepared composite. Generally the results show that washed banana peels have more effective than that of un-washed peels, adding banana peels could improve hardness of composite and hardness increase with increasing weight fraction of peels till specific value, (10) % wt. where highest hardness recorded, using high weight fraction of reinforcing phase could negatively effect into mechanical properties of composite, Also the results show that using banana fibers as reinforce phase, didin’t improve impact strength, fracture toughness, and modules of elasticity properties of acrylic.
Engineering machinery, tools, and implements, Mechanics of engineering. Applied mechanics
A new method of driving and controlling multiple piezoelectric actuators individually with a single power supply unit using variable resistors was developed, and its effectiveness was investigated. This method provides effective high-accuracy shape control under weight limitation as each actuator can have a desired voltage applied individually from the single power supply unit using variable resistors. It was observed that the proposed method can drive piezoelectric actuators without degrading their operational performance when compared to representative actuator driving methods. Moreover, a shape control utilizing the proposed method was demonstrated to be more accurate than the conventional grouping method of multiple piezoelectric actuators, by numerical analysis and experiments on cantilever beams.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
It is necessary for pantographs of Japanese high-speed trains to satisfy both low noise characteristics and insensitive lift force characteristics toward the variation in wind direction and in the shape of pantograph head due to wear. Taking particular note of the profile of the pantograph head, streamline-wise profile generally leads to low noise but sensitive lift force characteristics, and rectangular profile leads to less sensitive lift force characteristics but generates larger noise. It is therefore difficult to achieve the two characteristics at the same time in a passive way. The authors propose a solution for this trade-off by applying the pantograph equipped with smoothed profile pantograph head, which gives better performance in terms of aerodynamic noise, and actuator to actively control the lift force. One of the most difficult problem to employ active control techniques on a pantograph is the measurement of its lift force. This paper proposes a method for lift coefficient estimation with realistic measurement points. The basic idea of this method is measurement of the surface pressure on the pantograph head with the use of static holes. By applying LASSO regression which is known as one of the sparse modelling technique, only 5 static holes enables to estimate the lift force with sufficient accuracy just as the lift force estimated by using 34 static holes data. This means that the proposed method allows us to materialize a simpler measurement system.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
Rzeppa constant velocity joints are mainly used in the drive shafts of front wheel drive vehicles. This type of joint transmits driving torque through balls provided in the joint. The ball force that transmits the torque fluctuates periodically when a joint angle exists between the two transmitting axes. Although this ball force fluctuation influences joint performance aspects such as strength and durability, the reason why the ball force fluctuates is not clarified yet. To reduce ball force fluctuation, it is necessary to clarify the essential mechanisms behind the periodic fluctuation. First, this paper assumes that the ball forces are balanced with the secondary moment related to the driving torque and joint angle. A basic waveform of the ball force was constructed based on this assumption. In addition, a detailed analysis model of a Rzeppa joint was constructed, including the contact and friction forces acting on multiple parts of the joint, based on a multibody dynamics approach. This detailed joint model was validated by ball forces measured in an experiment, and converted into an ideal joint model disengaged from design and production restrictions. The basic waveform of the ball force was validated using analysis results computed using this ideal joint model. The theory that the ball forces are balanced with the secondary moment was validated. Moreover, the contribution of the design parameters of the detailed joint model to the ball force waveform was identified by conversion to the ideal model.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
Effect of fuel-air mixture diluted by inert gas on knock intensity was investigated by using a rapid compression and expansion machine. Dilution of fuel-air mixture decreased knock intensity. As the dilution ratio became high, increase in input heating value did not affect knock intensity too much although it shortened auto-ignition delay. Knock intensity is assumed to correlate with the pressure rising rate when the auto-ignition occurs. Knock intensity was shown as a function of the maximum pressure and the maximum temperature which affect the high temperature oxidation reaction rate.
Mechanical engineering and machinery, Engineering machinery, tools, and implements
Shuichi SAKAMOTO, Seiya TATSUZA, Munehiro ISHIDA
et al.
This study focuses on acoustic silencers on indoor-use doors positioned in an array. In this paper, we discuss our studies of side branch silencers which are built in the ventilation door. By designing and fabricating a special attachment, we were able to attach silencers to the measurement tube that had larger cross sections than the impedance measurement tube. Using this attachment, we measured acoustic transmission losses for each of six different prototype silencers. By adding orifice silencer effects, we obtained transmission losses across a wide frequency range. However, attenuation decreased in frequency ranges below the attenuation peak of the side branch tubes. A wedge-shaped longitudinal cross section for the side branch tubes can double the length of the silencer and develop lower-frequency attenuation effects, while maintaining the same volume. This wedge-shaped side branch tube is suitable for a long silencer placed side by side in an array formation. We performed theoretical analyses of acoustic transmission losses of silencers using the transfer matrix method based on a one-dimensional wave equation. We performed element decomposition on the transfer matrix for silencers with side branch tubes with a wedge-shaped longitudinal cross section. We obtained calculated results that were sufficiently valid compared to our experimental measurements.
Engineering machinery, tools, and implements, Mechanical engineering and machinery