Comparison of spectra using a Bayesian approach. An argument using oil spills as an example

The problem of assigning a probability of matching a number of spectra is addressed. The context is in environmental spills when an EPA needs to show that the material from a polluting spill (e.g., oil) is likely to have originated at a particular site (factory, refinery) or from a vehicle (road tanker or ship). Samples are taken from the spill, and candidate sources and are analyzed by spectroscopy (IR, fluorescence) or chromatography (GC or GC/MS). A matching algorithm is applied to pairs of spectra giving a single statistic (R). This can be a point-to-point match giving a correlation coefficient or a Euclidean distance or a derivative of these parameters. The distributions of R for same and different samples are established from existing data. For matching statistics with values in the range {0,1} corresponding to no match (0) to a perfect match (1) a beta distribution can be fitted to most data. The values of R from the match of the spectrum of a spilled oil and of each of a number of suspects are calculated and Bayes' theorem is applied to give a probability of matches between spill sample and each candidate and the probability of no match at all. The method is most effective when simple inspection of the matching parameters does not lead to an obvious conclusion; i.e., there is overlap of the distributions giving rise to dubiety of an assignment. The probability of finding a matching statistic if there were a match to the probability of finding it if there were no match, expressed as a ratio (called the likelihood ratio), is a sensitive and useful parameter to guide the analyst. It is proposed that this approach may be acceptable to a court of law and avoid challenges of apparently subjective opinion of an analyst. Examples of matching the fluorescence and infrared spectra of diesel oils are given.     

In situ fastening graphene sheets into a polyurethane sponge for the highly efficient continuous cleanup of oil spills

Oil sorbents are an attractive option for oil-spill cleanup as they may be used for collection and complete removal of oil without adversely affecting the environment.However,traditional oil sorbents exhibit low oil/water separation efficiency and/or low oil-sorpfion capacity.In this study,an ultra-high performance graphene/polyurethane (PU) sponge has been successfully obtained by in situ polymerization in the presence of graphene dispersed in N-methylpyrrolidone (NMP).During polymerization,the NMP/graphene dispersion not only serves as a weak amine catalyst for the formation of the sponge,but promotes fixation of the graphene sheets in the framework of the PU sponge owing to the strong dipole interaction between NMP and graphene.The as-prepared graphene/PU sponge was used as an absorbing material for the continuous removal of oil from oil-spill water.The graphene/PU sponge can continuously and rapidly remove oils from immiscible oil/water mixtures in corrosive solutions,including strong acids and bases,hot water,and ice water,with an excellent separation efficiency of above 99.99％.In addition,the as-prepared graphene/PU sponge was effective in separating surfactant-stabilized emulsions with a high separation efficiency of ＞99.91％.     

注取油循环荷载作用下地下水封油库运营性能评价

以我国首个大型地下水封油库工程为背景,采用理论分析和数值模拟等方法评价了注取油循环荷载作用下该油库运营期的稳定性与水封性。针对岩石疲劳力学特性,在常规运动硬化疲劳力学模型基础上,提出可考虑平均主应力影响的岩石疲劳力学模型;编写用户子程序,将所提模型嵌入有限元分析软件,实现了循环荷载作用下地下水封油库运营性能评价。评价过程中选取了同步注取和异步注取两种工况,从围岩稳定性和水封性两方面对洞库运营性能进行了分析评价。分析结果显示：同步注取石油对库区围岩拱顶沉降影响较大,异步注取石油对库区围岩水平收敛影响较大;异步注取条件下水位下降和涌水量均比同步注取条件大,但差异不大。两种工况下洞库运营期间总体稳定性和水封性均能保持良好。     

Preparation of H-oleoyl-carboxymethyl-chitosan and the function as a coagulation agent for residual oil in aqueous system

In this study, H-form oleoyl-carboxymethyl-chitosan (H-O-CMCS) was prepared as a coagulation agent to clean up the residual oil from the waste-water of oil extraction (WWOE). The Fourier transform infrared (FTIR) spectra confirmed the formation of an amide linkage between amino groups of carboxymethyl chitosan (CMCS) and carboxyl groups of oleic acid. The adsorption capacities of four absorbents (H-O-CMCS, chitosan, activated carbon and polyaluminium chloride (PAC)) for the residual oil were investigated. Compared with chitosan, activated carbon and PAC, H-O-CMCS was more effective in removing the residual oil from WWOE, which could successfully wash up almost 99% of residual oil from WWOE at the dosage of 0.2 g/L, the mixing time of 3 min, 500 rpm, and a broader range of pH (the system temperature ⩽ 45°C). In similar conditions, comparatively, chitosan, activated carbon and PAC could wash 90%, 82% and 92% of residual oil from WWOE, respectively.     

Preparation of H-oleoyl-carboxymethyl-chitosan and the function as a coagulation agent for residual oil in aqueous system

In this study, H-form oleoyl-carboxymethyl-chitosan (H-O-CMCS) was prepared as a coagulation agent to clean up the residual oil from the waste-water of oil extraction (WWOE). The Fourier transform infrared (FTIR) spectra confirmed the formation of an amide linkage between amino groups of carboxymethyl chitosan (CMCS) and carboxyl groups of oleic acid. The adsorption capacities of four absorbents (H-O-CMCS, chitosan, activated carbon and polyaluminium chloride (PAC)) for the residual oil were investigated. Compared with chitosan, activated carbon and PAC, H-O-CMCS was more effective in removing the residual oil from WWOE, which could successfully wash up almost 99% of residual oil from WWOE at the dosage of 0.2 g/L, the mixing time of 3 min, 500 rpm, and a broader range of pH (the system temperature ≤45°C). In similar conditions, comparatively, chitosan, activated carbon and PAC could wash 90%, 82% and 92% of residual oil from WWOE, respectively.     

Integrated light scattering as a function of wavelength in donor lenses.

The purpose of this work is to investigate the light-scattering properties of excised eye lenses with intact lens capsules--more specifically, to compare light scattering with light transmission at different wavelengths in aging and cataractous lenses. A lens is positioned at its focal-length distance from an optical fiber end and collimates the light from one of five laser lines (458-633 nm). By use of an integrating sphere with an extra circular port, the collimated directly transmitted light can be separated from the scattered light. For lenses with low light-scattering levels, integrated scattering showed a dependence on wavelength, but when light scattering increased the wavelength difference tended to level out. Despite the higher percentage of lens light scattering at lower wavelengths, when calculated as an "effective light scattering" (compensated for light transmission), more scattered light actually falls toward the retina at longer wavelengths.     

Zonation and assessment of frozen-ground conditions for engineering geology along the China-Russia crude oil pipeline route from Mo'he to Daqing, Northeastern China

The China-Russia Crude Oil Pipeline (CRCOP), 813 mm in diameter, is designed to transport 603,000 barrels of Siberian crude oil per day across 1030 km of frozen-ground. About 500 boreholes, with depths of 5 to 20 m, were drilled and cored for analyses, and the frozen-ground conditions were evaluated. After detailed surveys and analyses of the permafrost conditions along the pipeline route, a conventional burial construction mode at a nominal depth of 1.5 m was adopted. This paper discusses the principles and criteria for the zonation and assessment of the frozen-ground environments and conditions of engineering geology for the design, construction, and operation of the pipeline system based on an extensive and in-depth summary and analysis of the survey and exploration data. The characteristics of pipelining crude oil at ambient temperatures in the permafrost regions and the interactive processes between the pipeline and foundation soils were taken into account. Two zones of frozen-ground environment and conditions of engineering geology, i.e., seasonally-frozen-ground and permafrost, were defined on the basis of the regional distribution and differentiations in frozen-ground environments and conditions. Then, four subzones of the permafrost zone were classified according to the areal extent, taking into consideration the temperatures and thicknesses of permafrost, as well as changes in vegetation coverage. In the four subzones, 151 sections of engineering geology were categorized according to the ice/moisture contents of the permafrost, as well as the classes of frost-heaving and thaw-settlement potentials. These 151 sections are comprehensively summarized into four types for engineering construction and operation: good, fair, poor, and very poor, for overall conditions of engineering geology. The zonation, assessment principles and criteria have been applied in the design of the pipeline. They have also been used as the scientific bases for the construction, environmental management, operation and maintenance/contingency plans.     

Thermodynamic analysis of a diabatic two-phase flow for a pure refrigerant and a refrigerant/oil mixture under equilibrium conditions

Two different definitions of the vapor quality during a diabatic two-phase flow with and without the presence of oil are presented in this paper: the well-known vapor flow quality and the thermodynamic vapor quality. The vapor flow quality is based on the mass flow rates whereas the thermodynamic vapor quality is based on the mass. Two-phase thermodynamic diagrams for pure R-134a and R-134a/oil mixture are plotted for different slip ratios. It is shown that the iso-flow quality lines are moved to lower enthalpies for larger slip ratios. In addition, the maximum vapor flow quality of a fluid/oil mixture is shown to increase when increasing the slip ratio whereas the maximum thermodynamic vapor quality remains constant. In addition, the correct expression of the elementary derivative of the vapor quality is also proposed, highlighting the role of the heat capacity at constant vapor quality.     

Ion velocity distribution function in intrinsic gas plasma under conditions of resonance recharging as a main process. Experiment

For the first time, the ion distribution function over energies and directions of the motion for He+ in He and Ar+ in Ar is measured at the arbitrary value of the electric field by the method of the plane onesided probe. The experiment is carried out under conditions when the ion velocity acquired at the mean free path is on the order of and larger than the average thermal velocity of atoms and resonance recharging is the dominating process in plasma. The obtained results make it possible to conclude that, in independent gas discharge plasma, even at moderate fields where E/P = 10–20 V (cm Torr), the ion distribution function can have noticeable anisotropy and can strongly differ from the Maxwellian distribution.     

Ion velocity distribution function in intrinsic gas plasma under conditions of resonance recharging as a main process. Theory

An analytical solution is found for the kinetic Boltzmann equation for ions in natural gas at the arbitrary electric field strength in plasma under conditions where the dominating process is resonance recharging. The ion distribution function in the strong field coincides with the function obtained by authors earlier, and in the weak field it is close to the Maxwell’s function with the temperature of atoms. For the ambipolar field of arbitrary value, the dependence of the cross-section of resonance recharging on the relative velocity is taken into account. It is shown that the ion velocity distribution function essentially differs from the Maxwell’s and is determined by two parameters. Good agreement between the results of calculations of the drift velocity of He⁺ ions in He, Ar⁺ in Ar and the reduced mobility of N₂ ⁺ in N₂ and known experimental data is obtained in a wide range of reduced electric field values. The analytical calculations of the average energy of ions at different values of the reduced electric field are compared with the results of the numerical simulation using the Monte Carlo method performed by other authors.     

High-speed, whole-column fluorescence imaging detection for isoelectric focusing on a microchip using an organic light emitting diode as light source

An integrated and simplified microfluidic device using a 250 microm x 1-4 cm of organic light emitting diode (OLED) array as a two-dimensional light source for single-channel and multichannel whole-column imaging detection was developed. This fluorescence detection system was used for isoelectric focusing (IEF) of R-phycoerythrin in a microchip. The IEF conditions were optimized, and the total analysis time was extremely reduced to 30 s for 2-cm-long microchannels at 700 V/cm of electric field strength without the presence of electroosmotic flow. The compression of pH gradient caused by electrolytes drawing into the microchannels was efficiently restrained when 1% hydroxylpropylmethyl cellulose in 2% ampholyte was used as the carrier for IEF. Under optimized IEF conditions, the detection limit of this system was approximately 0.6 microg/mL or 45 pg at 75 nL/column injection of R-phycoerythrin. This OLED-induced fluorescence detection system for WCID provides a high-speed IEF technique with quantitative ability and the potential for high integration and throughput microchip systems.     

PROTEUS, a technical and management model for aquatic risk assessment of industrial spills

The assessment of risks to the aquatic environment related to industrial installations is a priority in environmental pollution control in the Netherlands. Major accidents to the surface water such as the Sandoz incident, but also the high number of smaller accidents that occur every year has invoked the need for an effective method to assess these risks. Two different models have been used in this field in the Netherlands over several years. These two software applications, VERIS and RISAM were developed from two different perspectives: VERIS from the perspective of supplying major accidents related information in the safety report, RISAM form the perspective of controlling risks for both smaller and larger facilities that may pollute surface waters through accidents. Both systems comprised particular strong points: VERIS considers safety management aspects in the assessment, RISAM considers differences in surface water vulnerability and involves quantitative probabilities in the assessment. It was decided to integrate both methods and maintain these strong points in the resulting method. This paper describes the new integrated risk assessment method that now has been developed in a concerted effort between the Ministry of Transport, Public Works and Water Management, the Ministry of Housing, Spatial Planning and Environment, and the National Institute for Public Health and Environment. It also describes the essential elements of the computer program PROTEUS that is based on the new method and that makes the assessment of aquatic risks for industrial activities an easy task, partly due to the automatic generation of the assessment report.     

Characterization of a vapor injection scroll compressor as a function of low,intermediate and high pressures and temperature conditions

The interest in two stage cycles has increased in the last years and some compressor manufacturers have commercialized compressors adapted to work in these conditions. Nevertheless, the information supplied by them usually is limited to certain design conditions defined by the application and extrapolation to other conditions is not straightforward. In this article a test campaign of an injection scroll compressor is presented. This test campaign was divided in two parts, on the first one a wide range of evaporating and condensing pressures for the intermediate conditions recommended by the manufacturer were measured, and the compressor behavior was systematically compared with single stage compressor of the same volume. On the second part an experimental study of the influence of the intermediate conditions on the performance have been done. The study has included the evaluation of the separate influence of intermediate gas superheat, intermediate pressure and wet injection.     

粗氩塔工况周期性恶化分析及处理

简述 6 0 0 0m3 /h空分设备粗氩塔运转 1～ 3个月后就出现工况周期性恶化的故障 ;经过分析检查 ,原因为管道变形、珠光砂进入所致 ;经 4项整改措施 ,粗氩塔工况恢复正常。     

Color changes in objects in natural scenes as a function of observation distance and weather conditions

We have analyzed the changes in the color of objects in natural scenes due to atmospheric scattering according to changes in the distance of observation. Hook-shaped curves were found in the chromaticity diagram when the object moved from zero distance to long distances, where the object chromaticity coordinates approached the color coordinates of the horizon. This trend is the result of the combined effect of attenuation in the direct light arriving to the observer from the object and the airlight added during its trajectory. Atmospheric scattering leads to a fall in the object's visibility, which is measurable as a difference in color between the object and the background (taken here to be the horizon). Focusing on color difference instead of luminance difference could produce different visibility values depending on the color tolerance used. We assessed the cone-excitation ratio constancy for several objects at different distances. Affine relationships were obtained when an object's cone excitations were represented both at zero distance and increasing distances. These results could help to explain color constancy in natural scenes for objects at different distances, a phenomenon that has been pointed out by different authors.