The utilization of palm kernel shells (PKS) as an alternative to conventional materials for construction is desirable to promote sustainable development. The purpose of this study is to investigate the properties of l...The utilization of palm kernel shells (PKS) as an alternative to conventional materials for construction is desirable to promote sustainable development. The purpose of this study is to investigate the properties of lightweight concrete produced with different sizes of PKS of 6, 8, 10, 12 mm and mix (consisting of 25% each of the four sizes). RPK sizes were used to replace coarse aggregate in the concrete and cured for 7, 14, 21 and 28 days. The tests performed on the concrete are dry density, compressive strength, flexural strength, EDS and SEM. It was revealed that the densities of the concrete specimens were all less than 2000 kg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, which implies that the PKS concrete satisfied the requirement of lightweight concrete for structural application. The compressive strength of the 12 mm PKS concrete specimens at 28-day of curing was 10.2 MPa which was 4% to 15.9% better than the other PKS sizes concrete. The flexural strength of the 12 mm PKS concrete specimens at 28-day of curing was 2.85 MPa which was also 3.2% to 57.07% better than the other PKS sizes concrete. It was also revealed by the SEM analysis that there was a good bond between the palm kernel shells and the mortar. A high calcium-silicate content was found in the concrete which resulted in a Ca/Si ratio of 1.26 and Al/Si ratio of 0.11. The study therefore concludes that size variations of PKS as replacement of coarse aggregate have an influence on the properties of the lightweight concrete and recommends 12 mm PKS for use by construction practitioners for lightweight concrete structural application</span></span></span><span style="font-family:Verdana;">.展开更多
在人体姿态检测任务中,现有的深度学习网络存在检测精度不足、网络参数复杂和计算成本高等问题,严重限制了它们的应用。为了解决这些问题,提出一种轻量且高精度的姿态检测改进网络HG-YOLO(High-precision and Ghost YOLO)。针对检测精...在人体姿态检测任务中,现有的深度学习网络存在检测精度不足、网络参数复杂和计算成本高等问题,严重限制了它们的应用。为了解决这些问题,提出一种轻量且高精度的姿态检测改进网络HG-YOLO(High-precision and Ghost YOLO)。针对检测精度不足的问题,在HG-YOLO的主干网络,融合基于Transformer的检测网络RT-DETR(Real-Time DEtection TRansformer),并将大型可分离核注意力(LSKA)模块嵌入主干网络中,以在不增加内存占用和计算复杂性的基础上,提高网络应对复杂场景的特征提取能力,从而提高人体姿态的检测精度。针对网络参数复杂和计算成本高的问题,引入轻量化的Ghost卷积模块替换部分标准卷积,此外,在HG-YOLO的检测头部分,设计一种共享卷积检测头,以通过参数和权重共享机制减少卷积计算,从而降低网络的参数量和计算复杂度。在COCO(Common Objects in COntext)2017-Keypoints数据集和CrowdPose数据集上的实验结果表明,与基准的YOLOv8-Pose网络相比,HG-YOLO的参数量减少了32%,浮点运算量减少了18%;在规模为小型(s)时,在COCO 2017-Keypoints数据集上,AP50(Average Precision at OKS(Object Keypoint Similarity)of 0.50)提升了0.8个百分点,在CrowdPose数据集上,AP提升了2.9个百分点。可见,HG-YOLO不仅轻量,而且检测精度高,是人体姿态检测领域的优秀网络模型。展开更多
文摘The utilization of palm kernel shells (PKS) as an alternative to conventional materials for construction is desirable to promote sustainable development. The purpose of this study is to investigate the properties of lightweight concrete produced with different sizes of PKS of 6, 8, 10, 12 mm and mix (consisting of 25% each of the four sizes). RPK sizes were used to replace coarse aggregate in the concrete and cured for 7, 14, 21 and 28 days. The tests performed on the concrete are dry density, compressive strength, flexural strength, EDS and SEM. It was revealed that the densities of the concrete specimens were all less than 2000 kg/m</span><sup><span style="font-family:Verdana;">3</span></sup><span style="font-family:Verdana;">, which implies that the PKS concrete satisfied the requirement of lightweight concrete for structural application. The compressive strength of the 12 mm PKS concrete specimens at 28-day of curing was 10.2 MPa which was 4% to 15.9% better than the other PKS sizes concrete. The flexural strength of the 12 mm PKS concrete specimens at 28-day of curing was 2.85 MPa which was also 3.2% to 57.07% better than the other PKS sizes concrete. It was also revealed by the SEM analysis that there was a good bond between the palm kernel shells and the mortar. A high calcium-silicate content was found in the concrete which resulted in a Ca/Si ratio of 1.26 and Al/Si ratio of 0.11. The study therefore concludes that size variations of PKS as replacement of coarse aggregate have an influence on the properties of the lightweight concrete and recommends 12 mm PKS for use by construction practitioners for lightweight concrete structural application</span></span></span><span style="font-family:Verdana;">.
