Geysering Generated by Large Air Pockets Released through Water-Filled Ventilation Shafts

One potential problem affecting below-grade storm-water storage tunnels is the occurrence of geysering, which is defined as the return of conveyed water to grade. Most investigations to date have linked this occurrence with inertial oscillation of the water within vertical shafts. Another mechanism that can lead to geysering is the release of air and water through ventilation towers. This study presents a systematic investigation on geysering caused by the release of large air pockets through partially water-filled ventilation towers. Parameters considered in the study included the water level in the ventilation tower, air-phase pressure head, and ventilation tower diameter. An important parameter in geysering was the diameter of the ventilation tower. A simplified numerical model was developed to simulate the experiments; it was able to reproduce the essential features of the experiments.     

新技术驱动雷击测试标准的发展

飞机新技术的发展,使人们必须重新审视飞机的雷击测试方法,以确保其耐受性。2007年12月,航空无线电技术委员会（RTCA）的飞机电磁兼容测试标准DO 160最新版F版发表,而欧洲民航设备组织（EUROCAE）也发布了与其等效的文件ED14。     

A feature binding model in computer vision for object detection

Multimedia Tools and Applications - In this paper, the authors propose the “Feature Binding (FB)” strategy in computer vision, a method combined with the biological visual perception...     

Phase Transition across Anisotropic NbS3 and Direct Gap Semiconductor TiS3 at Nominal Titanium Alloying Limit

Alloying selected layered transitional metal trichalcogenides (TMTCs) with unique chain-like structures offers the opportunities for structural, optical, and electrical engineering thus expands the regime of this class of pseudo-one-dimensional materials. Here, the novel phase transition in anisotropic Nb_(1−x)Ti_xS₃ alloys is demonstrated for the first time. Results show that Nb_(1−x)Ti_xS₃ can be fully alloyed across the entire composition range from triclinic-phase NbS₃ to monoclinic-phase TiS₃. Surprisingly, incorporation of a small concentration of Ti (x ≈ 0.05–0.18) into NbS₃ host matrix is sufficient to induce triclinic to monoclinic transition. Theoretical studies suggest that Ti atoms effectively introduce hole doping, thus rapidly decreases the total energy of monoclinic phase and induces the phase transition. When alloyed, crystalline and optical anisotropy are largely preserved as evidenced by high resolution transmission electron microscopy and angle-resolved Raman spectroscopy. Further Raman measurements identify Raman modes to determine crystalline anisotropy direction and offer insights into the degree of anisotropy. Overall results introduce Nb_(1−x)Ti_xS₃ as a new and easy phase change material and mark the first phase engineering in anisotropic van der Waals (vdW) trichalcogenide systems for their potential applications in two-dimensional superconductivity, electronics, photonics, and information technologies.     

Multi-objective optimization of cellular fenestration by an evolutionary algorithm

This paper describes the multi-objective optimized design of fenestration that is based on the façade of the building being divided into a number of small regularly spaced cells. The minimization of energy use and capital cost by a multi-objective genetic algorithm was investigated for: two alternative problem encodings (bit-string and integer); the application of constraint functions to control the aspect ratio of the windows; and the seeding of the search with feasible design solutions. It is concluded that the optimization approach is able to find near locally Pareto optimal solutions that have innovative architectural forms. Confidence in the optimality of the solutions was gained through repeated trail optimizations and a local search and sensitivity analysis. It was also concluded that seeding the optimization with feasible solutions was important in obtaining the optimum solutions when the window aspect ratio was constrained.     

Developing design guidelines for inclusive housing: a multi-stakeholder approach using a Delphi method

Increasing interest and investment in inclusive housing for people with complex disabilities has resulted in a greater focus on research evidence and industry replication. In the absence of practice standards and regulatory structures, building design principles and guidelines for purpose-built supported housing have an important role within the sector. The current project was a first attempt at developing a set of principles and design features that have the potential to inform future inclusive housing guidelines. The researchers applied a multi-stakeholder Delphi process to generate nine design principles to guide future supported housing, and a parsimonious set of design features (n = 247) across ten design spaces. The framework such as developed in this study can be further tested to develop a more robust understanding of what works in supported housing design, and therefore what can be replicated over time.     

In situ synchrotron study on the interplay between martensite formation, texture evolution and load partitioning in low-alloyed TRIP steels

We have studied the micromechanical behaviour of two low-alloyed multiphase TRIP steels with different aluminium contents by performing in situ high-energy X-ray diffraction experiments at a synchrotron source under increasing tensile stress levels. A detailed analysis of the two-dimensional diffraction data has allowed us to unravel the interplay between the martensite formation, the texture evolution and the load partitioning, and to correlate the observed behaviour to the macroscopic response of the material. The high aluminium content TRIP steel grade presents a higher volume fraction of retained austenite at room temperature that transforms more gradually into martensite under deformation, providing a larger uniform elongation. The comparison between the observed transformation behaviour and the texture evolution indicates that the 〈1 0 0〉 component along the loading direction corresponds to a low critical stress for the transformation. The evolution of the elastic strains revealed the occurrence of a significant load partitioning before reaching the macroscopic yield strength, which becomes more pronounced in the plastic regime due to the progressive yielding of the different grains in the polycrystalline material. This opens the door to tailor the austenite stability by altering the distribution in grain size, local carbon content, and grain orientation in order to produce the optimal load partitioning and work hardening for improved combinations of strength and formability in low-alloyed TRIP steels.     

Biosynthesis of the Fluorinated Natural Product Nucleocidin in Streptomyces calvus Is Dependent on the bldA‐Specified Leu‐tRNAUUA Molecule

Nucleocidin is one of the very few natural products known to contain fluorine. Mysteriously, the nucleocidin producer Streptomyces calvus ATCC 13382 has not been observed to synthesize the compound since its discovery in 1956. Here, we report that complementation of S. calvus ATCC 13382 with a functional bldA‐encoded Leu‐tRNA^UUA molecule restores the production of nucleocidin. Nucleocidin was detected in culture extracts by ¹⁹F NMR spectroscopy, HPLC‐ESI‐MS, and HPLC‐continuum source molecular absorption spectroscopy for fluorine‐specific detection. The molecule was purified from a large‐scale culture and definitively characterized by NMR spectroscopy and high‐resolution MS. The nucleocidin biosynthetic gene cluster was identified by the presence of genes encoding the 5′‐O‐sulfamate moiety and confirmed by gene disruption. Two of the genes within the nucleocidin biosynthetic gene cluster contain TTA codons, thus explaining the dependence on bldA and resolving a 60‐year‐old mystery.     

The relationship between some chemical parameters and sensory evaluations for plain black tea (Camellia sinensis) produced in Kenya and comparison with similar teas from Malawi and South Africa

Reliable and accurately measurable chemical parameters that can be used to estimate black tea quality are desirable in trade, research and breeding programmes. Using plain Kenyan black tea from 11 cultivars, which gave some significant differences in their plain black tea quality parameters, the individual theaflavins composition, total theaflavins, thearubigins, theaflavin digallate equivalent, total colour and brightness were determined. The parameters were regressed against sensory evaluation scores of two tasters A and B. The theaflavin digallate equivalent (TDE) showed the strongest relationship (r = 0.71 (P ? 0.01) and r = 0.80 (P ? 0.001)) for A and B′, respectively. The simple (non gallated) theaflavin and thearubigins did not show significant relationships with sensory evaluation. Of the liquor characteristics, there were significant relationships between liquor brightness and sensory evaluation by A and B (r = 0.58 (P ? 0.06) and r = 0.59 (P ? 0.05)), respectively. In consequence, TDE and brightness can be used in tea breeding programmes as quality indicators or to estimate plain black tea quality potential in the tea trade. Optimising their levels can also help to produce good quality Kenyan black teas during processing. Comparison of these results with work published earlier indicates that, of the individual theaflavins, theaflavin-3,3′-digallate correlates best with tea taster scores for the 11 Kenyan cultivars, whereas the simple theaflavin correlates best with tea tasters’ scores for 40 Malawian cultivars. However, the derived parameter, TDE correlates very well with tea tasters’ scores for all of the above cultivars.