Theoretical investigation of the thermal performance of a novel solar loop-heat-pipe façade-based heat pump water heating system

The aim of the paper was to present a dedicated theoretical investigation into the thermal performance of a novel solar loop-heat-pipe façade based heat pump water heating system. This involved thermo-fluid analyses, computer numerical model development, the model running up, modelling result analyses and conclusion. An energy balance network was established on each part and the whole range of the system to address the associated energy conversion and transfer processes. On basis of this, a computer numerical model was developed and run up to predict the thermal performance of such a system at different system configurations, layouts and operational conditions. It was suggested that the loop heat pipes could be filled with either water, R134a, R22 or R600a; of which R600a is the favourite working fluid owing to its relatively larger heat transfer capacity and positive pressure in operation. Variations in the system configuration, i.e., glazing covers, heat exchangers, would lead to identifiable differences in the thermal performance of the system, represented by the thermal efficiency and COP. Furthermore, impact of the external operational parameters, i.e., solar radiation and ambient air temperature, to the system's thermal performance was also investigated. The research was based on an innovative loop-heat-pipe façade and came up with useful results reflecting the thermal performance of the combined system between the façade and heat pump. This would help promote development and market penetration of such an innovative solar heating technology, and thus contribute to achieving the global targets in energy saving and carbon emission reduction

Ultrafast Euclidean Shortest Path Computation Using Hub Labeling

Finding shortest paths in a Euclidean plane containing polygonal obstacles is a well-studied problem motivated by a variety of real-world applications. The state-of-the-art algorithms require finding obstacle corners visible to the source and target, and need to consider potentially a large number of candidate paths. This adversely affects their query processing cost. We address these limitations by proposing a novel adaptation of hub labeling which is the state-of-the-art approach for shortest distance computation in road networks. Our experimental study conducted on the widely used benchmark maps shows that our approach is typically 1-2 orders of magnitude faster than two state-of-the-art algorithms

Mechanism of tunneling-induced cave-in of a busy road in Fukuoka city, Japan

A road cave-in accident caused by tunneling is described, and the possible mechanism of failure is analyzed. The cave-in measured about 30 m × 27 m in plane, and about 15 m in depth. At about 19 m below the ground surface at the site, a tunnel construction was underway. Immediately above the tunnel, there was a weathered shale layer approximately t 2.66 m thick; above this layer, there were sand and gravel layers. The groundwater level was estimated to be about 5 m below the ground surface. By arch analysis, it is shown that the most likely cause of the accident was the low strength of the weathered shale layer and the high water pressure above the tunnel, which resulted in tensile failure of the weathered shale layer. The All Ground Fasten (AGF) pre-support measure was adopted, but it might make very limited contribution to the increase in the tensile strength of the shale layer in the cross-sectional direction of the tunnel. Keywords: Tunneling, Road cave-in, Arch analysis, Tensile failur

Clinical effectiveness of calcitriol and calcium gluconate in treating older male patients with osteoporosis

Clinical studies on calcitriol in osteoporosis (OP) have been mostly conducted in postmenopausal women, with limited research reported in elderly male patients. In this study, we investigated the effects of combining calcitriol with calcium gluconate for treating OP in elderly men and compared it with calcium gluconate monotherapy to provide insights into the clinical treatment options for OP. A total of 86 elderly male OP patients were included in this study and randomly assigned to control or observation groups in a 1:1 ratio. The control group was given oral calcium gluconate (1.0 g, three times daily), while the observation group was given oral calcitriol capsule (0.25 μg twice daily) and oral calcium gluconate (1.0 g three times daily). The results indicated that treatment with single calcium gluconate for 6 months had minimal impact on the bone mineral density (BMD) of the lumbar spine, total hip and femoral neck, and balance function. In contrast, the combination of calcium gluconate and calcitriol significantly increased BMD and improved patients’ balance function. Both single calcium gluconate treatment and the combination of calcium gluconate and calcitriol affected various bone metabolism and turnover markers to varying degrees, including a decrease in the level of tartrate-resistant acid phosphatase-5b (TRAP-5b) and an increase in the levels of osteocalcin and calcium. Both calcium gluconate and calcitriol affect patients’ bone metabolism and turnover markers to varying degrees. Importantly, the combination of calcium gluconate and calcitriol had a significant effect on these markers compared to calcium gluconate monotherapy, and no significant difference in the incidence of adverse reactions was observed between the two groups during treatment. Calcium gluconate in combination with calcitriol in elderly male patients with OP may increase bone mineral density, improve bone metabolism, enhance bone turnover and maintain a high safety profile

Consolidation analysis of clayey deposits under vacuum pressure with horizontal drains

A method has been developed for the consolidation analysis of dredged mud or clayey soil deposits containing strip-type, prefabricated horizontal drains (PHDs), based on either the axisymmetric or plane strain unit cell theory. An approximate consolidation theory has also been proposed for a surface soil layer subjected to vacuum pressure applied through the PHDs at a shallow depth from the surface. The proposed method and the consolidation theory have then been applied to the analysis of a field project in Japan involving dredged mud consolidated by vacuum pressure with PHDs. By comparing the field-measured and analyzed results in terms of water content distributions with depth and the thickness variation of the deposit, the usefulness of the proposed method has been demonstrated

AN IMPROVED ALGORITHM FOR TIME DOMAIN AVERAGING BASED ON FRACTIONAL DELAY FILTERING

For reducing the influence of truncation error on the accuracy of time domain averaging（ TDA） induced by noninteger-period sampling,an improved algorithm of TDA based on fractional delay filtering（ FDF） is presented.On the basis of analyzing the disadvantages of current methods of TDA and the characteristics of FDF,a presently improved method of signal truncation was used in the method to avoid the accumulation of truncation error and obtain a delay factor on each of the truncated signals,the reconstruction and resample for the truncated signals were implemented with FDF,and finally the arithmetic mean were computed after all of the truncated signals were added.The theoretical analysis and experimental results demonstrate that the method which fully makes using of the advantages of FDF on the change of delay factor,apparently reduces the truncation error of signals with non-integer-period sampling,and could obviously improve the accuracy of TDA without key-phase signal

Numerical investigation of the failure of a building in Shanghai, China

The overturning failure of a 13 storey residential building in Shanghai, China, has been investigated by plane strain finite element analysis (FEA). The results of the FEA indicate that ultimate failure of the building was probably initiated by the formation of tensile cracking in the reinforced concrete piles located under the side of the building adjacent to an excavation. This eventually led to complete structural failure of the piles located along the excavation side, which probably caused further settlement of the building, leading eventually to a toppling failure resulting in overturning of the entire building. Excessive tensile stress in the piles was probably caused by the combination of excavation of soil at one side of the building and the temporary dumping of the excavated soil on the opposite side of the building. It is likely that the effect of temporary dumping of the excavated soil adjacent to the building was either not considered or not properly taken into account in the foundation design nor the construction operations. A simple but important lesson to be draw from this failure is the need for engineers who design foundations in soft soil regions to consider not only the final loading conditions, but also any temporary and transient loading conditions during the construction process