Human reliability analysis of an offshore emergency blowdown system

An offshore platform depressurisation (blowdown) system was designed such that control in emergencies necessitated operator actions over a short space of time. The system design for these operations was analysed using a simple and pragmatic human reliability approach, embedded within a comprehensive risk assessment. The human reliability analysis identified several ways in which human actions could lead to system failure (flare overload), and in the total risk analysis these errors were found to dominate the risk picture. The causes of the human error related primarily to the design of the interface and co-ordination/communication problems previously unaddressed by the design process. Recommendations were made to reduce error potential based on the causes and mechanisms of error identified in the analysis, and several of these recommendations were included in the final design of the system.     

An integrated research tool for X-ray imaging simulation

This paper presents a software simulation package of the entire X-ray projection radiography process including beam generation, absorber structure and composition, irradiation set up, radiation transport through the absorbing medium, image formation and dose calculation. Phantoms are created as composite objects from geometrical or voxelized primitives and can be subjected to simulated irradiation process. The acquired projection images represent the two-dimensional spatial distribution of the energy absorbed in the detector and are formed at any geometry, taking into account energy spectrum, beam geometry and detector response. This software tool is the evolution of a previously presented system, with new functionalities, user interface and an expanded range of applications. This has been achieved mainly by the use of combinatorial geometry for phantom design and the implementation of a Monte Carlo code for the simulation of the radiation interaction at the absorber and the detector.     

Modulational Instability of Optical Vortices in Engineered Saturable MediaOA

Propagation of light beams in turbid media such as underwater environments,fog,clouds,or biological tissues finds increasingly important applications in science and technology,including bio-imaging,underwater communication,and free-space communication technologies.While many of these applications traditionally relied on conventional,linearly polarized Gaussian beams,light possesses many degrees of freedom that are still largely unexplored,such as spin angular momentum(SAM) and orbital angular mo...     

痛挽往昔 瞻望来者——巴米扬窟龛考

本文整理出巴米扬山谷遗址群的年代学证据，旨在重现大佛的历史与图像地位。首先介绍了巴米扬山谷遗址群的研究方法和年代阶段，接着讨论玄奘所见所录的大佛的原始配置，最后将三尊佛像放入其原始的图像志语境中去考查，认为涅檗像原应位于38米大佛和55米大佛之间。后者为宝装焰肩佛，其神格应为燃灯佛；38米大佛为释迦佛。而巡礼者所遵循的应是燃灯佛-释迦佛-涅粲佛-弥勒佛的绕拜顺序。     

细粒土吸附结合水含量的测定及工程应用

本文测定了细粒土中吸附水的含量及其密度,并根据测试结果改进了固相压实度和土的空隙率计算方法.选取了我国不同地区的4种细粒土,用热重法和容量瓶法测定了4种细粒土的吸附水含量和密度;利用扫描电镜和X射线衍射分析了各土样吸水能力的差异.为了研究吸附水的压缩特性,采用固结法对4种饱和土样进行了试验.结果表明,吸附水的解吸温度范...     

Remote plasma enhanced chemical deposition of non-crystalline GeO2 on Ge and Si substrates

Non-crystalline GeO2 films remote were plasma deposited at 300 degrees C onto Ge substrates after a final rinse in NH4OH. The reactant precursors gas were: (i) down-stream injected 2% GeH4 in He as the Ge precursor, and (ii) up-stream, plasma excited O2-He mixtures as the O precursor. Films annealed at 400 degrees C displayed no evidence for loss of O resulting in Ge sub-oxide formation, and for a 5-6 eV mid-gap absorption associated with formation of GeOx suboxide bonding, x < 2. These films were stable in normal laboratory ambients with no evidence for reaction with atmospheric water. Films deposited on Ge and annealed at 600 degrees C and 700 degrees C display spectra indicative of loss of O-atoms, accompanied with a 5.5 eV absorption. X-ray absorption spectroscopy and many-electron theory are combined to describe symmetries and degeneracies for O-vacancy bonding defects. These include comparisons with remote plasma-deposited non-crystalline SiO2 on Si substrates with SiON interfacial layers. Three different properties of remote plasma GeO2 films are addressed comparisons between (i) conduction band and band edge states of GeO2 and SiO2, and (ii) electronic structure of O-atom vacancy defects in GeO2 and SiO2, and differences between (iii) annealing of GeO2 films on Ge substrates, and Si substrates passivated with SiON interfacial transition regions important for device applications.     

Probing the electromagnetic field distribution within a metallic nanodisk

A Co nanolayer is used as a local probe to evaluate the vertical inhomogeneous distribution of the electromagnetic (EM) field within a resonant metallic nanodisk. Taking advantage of the direct relation between the magneto-optical activity and the electromagnetic field intensity in the Co layer, it is shown that the nonuniform EM distribution within the nanodisk under plasmon resonant conditions has maximum values close to the upper and lower flat faces, and a minimum value in the middle.     

Multifunctional picoliter droplet manipulation platform and its application in single cell analysis

We developed an automated and multifunctional microfluidic platform based on DropLab to perform flexible generation and complex manipulations of picoliter-scale droplets. Multiple manipulations including precise droplet generation, sequential reagent merging, and multistep solid-phase extraction for picoliter-scale droplets could be achieved in the present platform. The system precision in generating picoliter-scale droplets was significantly improved by minimizing the thermo-induced fluctuation of flow rate. A novel droplet fusion technique based on the difference of droplet interfacial tensions was developed without the need of special microchannel networks or external devices. It enabled sequential addition of reagents to droplets on demand for multistep reactions. We also developed an effective picoliter-scale droplet splitting technique with magnetic actuation. The difficulty in phase separation of magnetic beads from picoliter-scale droplets due to the high interfacial tension was overcome using ferromagnetic particles to carry the magnetic beads to pass through the phase interface. With this technique, multistep solid-phase extraction was achieved among picoliter-scale droplets. The present platform had the ability to perform complex multistep manipulations to picoliter-scale droplets, which is particularly required for single cell analysis. Its utility and potentials in single cell analysis were preliminarily demonstrated in achieving high-efficiency single-cell encapsulation, enzyme activity assay at the single cell level, and especially, single cell DNA purification based on solid-phase extraction.     

Rheological characterization of xanthan suspensions of nanoscale iron for injection in porous media

Nanoscale zerovalent iron (NZVI) represents one of the most interesting reagents for the remediation of contaminated aquifers, but its application is hindered by a lack of colloidal stability. Prior studies have shown that nanoscale iron slurries can be successfully stabilized against aggregation and sedimentation through dispersion in xanthan solutions; thus, further research was carried out by focusing on the flow behavior of xanthan-modified NVZI suspensions. This work aims at understanding the rheological properties of NZVI-xanthan suspensions, which have been extensively tested under two different flow conditions: simple shear flow and flow through a porous medium. According to both experimental approaches, the suspensions show a shear thinning behavior that is dependent on iron concentration. These rheological properties are explained by referring to the microstructure of the colloidal system. Flow equations have been formulated and solved in radial coordinates in order to demonstrate the feasibility of such suspensions in field scale applications.     

Pixel selection for near-infrared chemical imaging (NIR-CI) discrimination between fish and terrestrial animal species in animal protein by-product meals

This paper proposes a method based on near-infrared hyperspectral imaging for discriminating between terrestrial and fish species in animal protein by-products used in livestock feed. Four algorithms (Mahalanobis distance, Kennard-Stone, spatial interpolation, and binning) were compared in order to select an appropriate subset of pixels for further partial least squares discriminant analysis (PLS-DA). The method was applied to a set of 50 terrestrial and 40 fish meals analyzed in the 1000-1700 nm range. Models were then tested using an external validation set comprising 45 samples (25 fish and 20 terrestrial). The PLS-DA models obtained using the four subset-selection algorithms yielded a classification accuracy of 99.80%, 99.79%, 99.85%, and 99.61%, respectively. The results represent a first step for the analysis of mixtures of species and suggest that NIR-CI, providing valuable information on the origin of animal components in processed animal proteins, is a promising method that could be used as part of the EU feed control program aimed at eradicating and preventing bovine spongiform encephalopathy (BSE) and related diseases.