Aerodynamic Characteristics Analysis of Ultra-High-Speed Elevator with Different Hoistway Structures

The high-speed airflow generated by ultra-high-speed elevators causes significant aerodynamic force, which seriously reduces the comfort and safety of passengers. First, a multi-parameter general model of ultra-high-speed elevator was established, and the three-dimensional numerical simulation of incompressible flow in the ultra-high-speed elevator was simulated. The correctness of the model and method was verified by experiments and grid-independence analyses. On this basis, the variation in the aerodynamic forces and the pressure in the hoistway was analyzed. Finally, the influence of different hoistway structures and parameters of ventilation holes on the aerodynamic forces and hoistway pressure were analyzed. The results showed that the opening of ventilation holes significantly reduced the aerodynamic forces and hoistway pressure for most of the period of the car’s operation period, but both the aerodynamic forces and hoistway pressure showed a sudden increase–decrease process. The aerodynamic forces and hoistway pressure were highly sensitive to changes in the hoistway blockage ratio, the cross-sectional area of the ventilation hole, and the position of the ventilation hole. When a pair of ventilation holes were opened, those in the middle of the hoistway reduced aerodynamic problems in the hoistway to the greatest extent. The increase in the connection angle between the ventilation hole and the hoistway eliminated the low-speed recirculation zone at the ventilation hole and increased the total volume of exhaust air at the ventilation hole.

Influence of the Variable Cross-Section Stator Ventilation Structure on the Temperature of an Induction Motor

The performance of an induction motor, a core component of the high-speed train, is of critical importance to the safety of the train. As a result of limited space in the train and the motor’s high-power density, motor heating poses a grave threat to its service life and operational safety. In this study, a 600-kW high-speed train induction motor model was established and its temperature field calculated by the finite volume method. To optimize the heat dissipation and further reduce the motor temperature rise, a variable cross-section stator ventilation hole was proposed and its influence on the wind velocity and temperature rise comprehensively studied. After comparing the cooling effect of the linear and nonlinear variable cross-section of the ventilation hole, the influence of the cross-sectional diameter and the radial position of the ventilation hole on the temperature rise was explored. Finally, the most favorable scheme for motor heat dissipation was determined.

Reducción de tiempos muertos en operación de corte de agujeros de ventilación, en estampado de rines de acero

A company’s productivity improvement is multi-causal, one of the causes being the reduction of time. That is why this article presents the methodology that a transnational automotive company performs to reduce downtime in the ventilation hole cutting operation, since it is a critical process that directly affects the productivity of the company. This project was carried out with the DMAIC methodology, in which the diagnosis is made through Ishikawa and Pareto, continuing the analysis of time. As part of the analysis of downtimes, the most frequent failures are included, as well as preventive maintenance and specifically tooling. Information is presented regarding the areas of opportunity, implementation of improvement strategies delimited by the design of an awl. Finally, it shows the reduction of time in the change of tooling, through the implementation of the improvements.

HUBUNGAN VENTILASI DENGAN KEJADIAN PENYAKIT ISPA PADA SANTRI DI PONDOK PESANTREN AMANATUL UMMAH SURABAYA

The incidence of Acute Respiratory Infections (ISPA) at the Amanatul Ummah Surabaya Islamic Boarding School is the biggest disease experienced by santri. This study aims to analyze the relationship between ventilation with the incidence of ISPA in students at the Amanatul Ummah Surabaya Islamic Boarding School. Cross sectional and Stratified Random Sampling consist of of 91 male and 116 female students were used in this study.data was obtained through extensive ventilation field observations. Secondary data was obtained from the medical record books of the students to obtain information on the history of the incidence of ISPA experienced by respondents over the past 1 year. The data analysis by chi-square test (α=0.05). The results showed that most (73.9%) respondents had ventilation conditions that did not meet the requirements and most (54.1%) sufferred from ISPA. The results showed a significant correlation between the ventilation condition and the incidence of ISPA (p=0.001). The more ventilation does not meet the requirements, the more likely the respondents were to suffer from ISPA. It was recommended that the islamic boarding schools evaluate the construction of the islamic boarding schools, especially related to the ventilation hole area of the students rooms to fit the applicable health requirements.

RapidNAM: generative manufacturing approach of nasoalveolar molding devices for presurgical cleft lip and palate treatment

Nasoalveolar molding (NAM) is an accepted treatment strategy in presurgical cleft therapy. The major drawbacks of the treatment listed in the literature relate to the time of the treatment and the coordination of the required interdisciplinary team of therapists, parents, and patients. To overcome these limitations, we present the automated RapidNAM concept that facilitates the design and manufacturing process of NAM devices, and that allows the virtual modification and subsequent manufacture of the devices in advance, with a growth prediction factor adapted to the patient’s natural growth. The RapidNAM concept involves (i) the prediction of three trajectories that envelope the fragmented alveolar segments with the goal to mimic a harmonic arch, (ii) the extrusion from the larger toward the smaller alveolar segment along the envelope curves toward the harmonic upper alveolar arch, and (iii) the generation of the NAM device with a ventilation hole, fixation pin, and fixation points for the nasal stents. A feasibility study for a vector-based approach was successfully conducted for unilateral and bilateral cleft lip and palate (CLP) patients. A comparison of the modified target models with the reference target models showed similar results. For further improvement, the number of landmarks used to modify the models was increased by a curve-based approach.