Search Results (4)

Fires in buildings result in the undesirable loss of life and property. Despite fire safety designs, the frequent occurrence of fires indicates a need for improvements in fire safety management. Conventional fire safety management is based on regulations managed separately by different parties at various stages of a building’s lifecycle. This study aims to present a conceptual framework for building information modeling (BIM)-based fire safety and risk management using the fire dynamics simulator (FDS) for a three-story building. A BIM model was developed for the building with fire safety compliance checks, and a simulation was conducted using FDS to integrate the results into the BIM model and test the model’s feasibility. The framework process consists of modeling, analysis, data integration, and user education. The BIM model was developed using Revit during the modeling stage and evaluated for fire safety compliance using Dynamo scripts. Concurrently, FDS simulations were performed for fire risk assessment in various scenarios, and evacuation route planning was established, considering the available evacuation time obtained from FDS results. Fire safety information, such as available evacuation time and optimal evacuation paths, was then integrated back into the BIM model for data integration using Dynamo scripts. In the model, fire safety compliance and simulation results were successfully integrated into the BIM model, serving as a platform for effective fire safety and risk management and providing fire safety information for building residents. Full article

Soil desiccation cracks in natural clayey soil pose significant risks to the stability of civil and geotechnical structures. Traditional methods for detecting these cracks are often inefficient and prone to inaccuracies. Therefore, we applied a deep learning approach of semantic segmentation based on DeepLabv3+ to detect desiccation cracks. To enhance computational efficiency, a pretrained lightweight network, MobileNetV2, was employed as the backbone for the DeepLabv3+ model. The model was trained and tested on a dataset of natural clayey soil crack images obtained through laboratory tests. Evaluation metrics including precision, recall, F1 score, and intersection over union (IoU) were used to assess the segmentation performance. The model took 17.13 min to train and achieved an inference speed of 0.43 s per image. DeepLabv3+ achieved better performance than the traditional segmentation method, with a precision of 95.76%, a recall of 84.12%, an F1 score of 89.56%, and an IoU of 81.10%. The model also demonstrated the capability to handle images with shading conditions and the presence of spots. DeepLabv3+ with MobileNetV2 as a backbone network was proven to be effective and efficient as a backbone in soil desiccation crack detection and segmentation. Full article

Unforeseen ground conditions are some of the main contributors to construction cost over-runs and late completion. Recent research trends have witnessed the scopes of building information modeling (BIM) technology being extended to subsoil and substructure constructions, or simply known as geotechnical BIM. This paper aimed to explore the procedures of developing 3D subsoil models through two case studies in Malaysia. The geotechnical BIM processes were performed by commercial software, AutoCAD Civil 3D 2017, with the extension of the Geotechnical Module. The modeling procedures can be divided into three main stages, namely data collection, data interpretation, and data visualization. The subsoil models were successfully developed at different levels of detailing to serve for different applications. The results showed that the 3D subsoil modeling required huge modeling and computational efforts, particularly when dealing with tropical residual soil profiles in Malaysia that are highly intricate. Thus, an adequate soil strata generalization was required to simplify the generated subsoil model. Data collection and management was identified as one of the main challenges of promoting geotechnical BIM in Malaysia at a macro-scale. Despite the challenges, successful implementation of the geotechnical building information in the present case studies were proved to be capable of promoting interoperability of soil data, which is an essential element in sustainable construction. Full article

Chronic hypoxia induces pulmonary hypertension and vascular remodeling, which are clinically relevant to patients with chronic obstructive pulmonary disease (COPD) associated with a decreased level of nitric oxide (NO). Oxidative stress and inflammation play important roles in the pathophysiological processes in COPD. We examined the hypothesis that daily administration of melatonin (10 mg/kg) mitigates the pulmonary hypertension and vascular remodeling in chronically hypoxic rats. The right ventricular systolic pressure (RVSP) and the thickness of pulmonary arteriolar wall were measured from normoxic control, vehicle- and melatonin-treated hypoxic rats exposed to 10% O₂ for 14 days. Levels of markers for oxidative stress (malondialdhyde) and inflammation (tumor necrosis factor-α (TNFα), inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2)) and the expressions of total endothelial NO synthase (eNOS) and phosphorylated eNOS at serine1177 (ser1177) were determined in the lung tissue. We found that the RVSP and the thickness of the arteriolar wall were significantly increased in the vehicle-treated hypoxic animals with elevated levels of malondialdhyde and mRNA expressions of the inflammatory mediators, when compared with the normoxic control. In addition, the phosphorylated eNOS (ser1177) level was significantly decreased, despite an increased eNOS expression in the vehicle-treated hypoxic group. Melatonin treatment significantly attenuated the levels of RVSP, thickness of the arteriolar wall, oxidative and inflammatory markers in the hypoxic animals with a marked increase in the eNOS phosphorylation in the lung. These results suggest that melatonin attenuates pulmonary hypertension by antagonizing the oxidative injury and restoration of NO production. Full article