Temperature and acid droplet size effects in acid neutralization of marine cylinder lubricants

Temperature and acid droplet size effects on the rate of acid neutralization by Marine Cylinder Lubricants were investigated by using a heating-capillary video microscopy. The neutralization experiments were performed inside a ∼200-μm capillary micro-reactor and the progress of reaction was recorded in real time. Increasing temperature dramatically impacted on the neutralization rate. While the effect of acid droplet size was negligible initially, it might affect the rate as well when a droplet got smaller than a certain level.     

Ostwald ripening: a decisive cause of cylinder corrosive wear

Acids formed from fuel combustion and lubricating oil breakdown can promote corrosive engine wear. Using capillary video-microcopy to investigate the neutralization of sulfuric acid droplets by overbased additives in lubricating oil, we have found that the Ostwald ripening of acid droplets may be a decisive factor of corrosive wear because it prolongs the lifetime of larger acid droplets. This finding provides a new understanding of how acids corrode engine parts, and in particular, why the most corrosive engine wear often occurs at piston top dead center, and may lead to new strategies for engine designs and lubricating oil additives.     

长江葛洲坝下游鱼类资源量的关键水文指标识别

采用遗传规划法和相关系数法识别影响鱼类资源量的关键水文指标,结果显示坝下经济鱼类天然捕捞产量与年最大流量、高流量脉冲历时、10月和12月的月均流量正相关;四大家鱼鱼苗丰度与涨水率、7日最大流量、5月和6月的月均流量正相关;中华鲟繁殖群体数量与基流指数和涨水率呈正相关,与年最小流量、日均流量逆转次数负相关。这些水文指标分别反映了流量的量值、变化率和历时等特征对鱼类的影响。建立了关键水文指标与鱼类资源量之间的非线性函数关系式,通过对比计算值与实测值发现遗传规划法的拟合效果明显优于相关系数法,表明遗传规划法更适用于识别影响鱼类资源量的关键水文指标。     

A Heuristic Evaluation for Deaf Web User Experience (HE4DWUX)

Websites that are usable and accessible can have a positive impact on the overall user experience. Usability Inspection Methods (UIMs) can be applied to evaluate and measure the usability. The current research in the fields of Web Accessibility and Human –Computer Interaction (HCI) is in need of additional UIMs that can be applied to also measure the accessibility, in addition to the usability alone. In this article, a novel UIM in the form of a heuristic evaluation is presented. The heuristic evaluation aims to support HCI experts and Web developers in designing and evaluating websites that provide positive user experiences to users who are deaf. This article discusses the development of the Heuristic Evaluation for Deaf Web User Experience (HE4DWUX). Following an iteration cycle, version 2 of the HE4DWUX is presented in Appendix A. An existing three-phase process to develop heuristics for specific application domains was applied to construct the HE4DWUX. The outcome of this research is 12 heuristics, with each containing its own set of checklist items to operationalize its applicability in measuring the Web user experience for users who are deaf. The heuristics and their checklist items can identify important aspects of design that will impact the Web user experience for this particular user group.     

Collaborative work during interventional radiological procedures based on a multicast satellite-terrestrial network.

Collaboration is a key requirement in several contemporary interventional radiology procedures (IRPs). This work proposes a multicast hybrid satellite system capable of supporting advanced IRP collaboration, and evaluates its feasibility and applicability. Following a detailed IRP requirements study, we have developed a system which supports IRP collaboration through the employment of a hybrid satellite-terrestrial network, a prototype multicast version of wavelet based interactive communication system (WinVicos) application, and a partition aggregation and conditional coding (PACC) wavelet codec. A semistructured questionnaire was also used to receive evaluative feedback from collaborating participants. The departments of interventional radiology of University Hospital of Patras, Greece and of Charite Hospital of Berlin, Germany have been connected on the system. Eight interventional radiologists and a vascular surgeon participated periodically in three satellite-terrestrial "fully collaborative" IRPs (average time 90 min) of high complexity and in four terrestrial educational sessions with great success, evidenced by considerable improving the IRP outcomes (clinical and educational). In case of high complexity, where the simultaneous presence of remote interventional expert and/or surgeon is required, advanced collaboration among staff of geographically dispersed international centers is feasible via integration of existing networking and other technologies.     

Suitable thermal insulation solutions for Mediterranean climatic conditions: a case study for four Greek cities

The selection of thermal insulation solutions has to satisfy many criteria: energy performance is the obvious one, structural and safety performance is a prerequisite, and environmental and economic aspects are those that can make the difference. However, especially when buildings operate under the Mediterranean climates, where outdoor conditions have to be mitigated by the building fabric throughout the year, the contribution of an insulation solution to indoor thermal comfort is also an important issue. In this approach, an integrated decision support system was applied to assess thermal insulation practices used commonly in residential buildings in the Mediterranean area. The system assesses the buildings’ elements over their life cycle, with thermal comfort being evaluated by means of the PMV/PPD index. Twenty-three thermal insulation configurations were considered, with different locations (internal, middle, external), materials (expanded polystyrene, extruded polystyrene, stone wool), and thicknesses. As the results showed, the position and the thickness of the insulation materials have a large impact on the energy consumption, the overall environmental impact, and the life cycle cost of the building, while thermal comfort was affected to a lesser degree.     

On the kinematics of multiple manipulator space free-flyers and their computation

In this article, two basic approaches for kinematics modelling of multiple manipulator space free-flying robots (SFFRs) are developed. In the barycentric vector approach, the center of mass of the whole system is taken as a representative point for the translational motion of the system, and a set of body-fixed vectors which reflect both geometric configuration and mass distribution of the system are used. On the other hand, the direct path method relies on taking a point on the base body (preferably its center of mass) as the representative point for the translational motion of the system. The consequences of using each of the two approaches in deriving dynamics equations and in control design of SFFRs are discussed. It is revealed that the direct path method is a more appropriate approach for modelling multiple arm systems, in the presence of external forces/torques (i.e., free-flying mode). A 14 degree-of-freedom space free-flying system is considered as a benchmark system and a quantitative comparison between the two approaches is presented. The results show that the direct path method requires significantly less computations for position and velocity analyses. © 1998 John Wiley & Sons, Inc.     

Optimization of electrically conductive films: Poly(3-methylthiophene) or polypyrrole in Kapton

A method to generate conductive films composed of small amounts of conductive polymer absorbed into the surface of polyimide films has been optimized. Both pyrrole (PY) and 3-methylthiophene (3MT) were evaluated as precursors for the conductive phase. Predictive models were empirically derived for each precursor to describe the effects of polymerization variables on the conductivity of the films. The variables studied were found to be highly synergistic. An optimum set of conditions was found for each conductive polymer that produces the highest conductivity. Using p-3MT as the conductive phase, films with conductivity as high as 5.7 Ω⁻¹ cm⁻¹ can be produced, an improvement of four orders of magnitude over previously reported results with Kapton as a base polymer. The highest conductivity achieved using p-PY as the conductive phase was 0.041 Ω⁻¹ cm⁻¹, still a two order of magnitude improvement over previously reported results. Mean mechanical properties of the 3MT-treated films were not significantly lower than that for untreated Kapton. The conductivities of p-3MT/Kapton films tested over time under ambient temperature in air persist fairly well for 300 days. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 821–834, 1997     

Arsonoliposomes: novel nanosized arsenic-containing vesicles for drug delivery

Natural and synthetic arsenolipids, have been discovered, synthesized, and evaluated for their biological activity. Arsonolipids, are analogs of phosphonolipids, in which P has been replaced by As. The synthesis of arsonolipids has been explored and a simple one-pot method with high yield is currently available for their preparation. However, although arsonolipids posses interesting biophysical and biochemical properties their anticancer or antiparasitic activity is not considered adequate for therapeutic applications. But when arsonolipids are incorporated in liposomes, the vesicles formulated have interesting possibilities, as seen in a number of studies. In cell culture studies, nanosized arsonolipid-containing liposomes or else arsonoliposomes, showed increased toxicity against cancer cells (compared to that of arsenic trioxide) but at the same time were less toxic than arsenic trioxide for normal cells. Furthermore, arsonoliposomes also demonstrate antiparasitic activity in vitro. Nevertheless, As is rapidly cleared from blood after in vivo administration of arsonoliposomes, and this will highly limit possible therapeutic applications. In addition, the fact that arsonoliposomes were observed to aggregate and subsequently fuse into larger particles in presence of cations, may also be considered as a problem. Thereby, methods to modulate the stability of arsonoliposomes and, perhaps, their in vivo distribution (as surface property modification) are currently being investigated. In very recent experiments it has been shown that arsonoliposome pegylation results in the formation of liposomes with very high membrane integrity. In addition, pegylation results in increased physical stability of arsonoliposomes and abolishment of cation-induced aggregation and fusion. Nevertheless, further in vivo studies are required in order to prove if pegylation alters arsonoliposome in vivo kinetics in a positive way, without affecting their activity. From studies performed thus far it is concluded that arsonoliposomes are nanosized-vesicles with interesting properties that justify further exploitation towards the development of therapeutic systems for cancer or parasitic diseases.     

Modeling Unsteady Flow Characteristics of Hydropeaking Operations and Their Implications on Fish Habitat

Reservoir releases associated with energy production and flood mitigation need to be reconciled with efforts to maintain healthy ecosystems in regulated rivers. Unsteady flow phenomena caused by hydropeaking operations typically affect riverbed erosion and fish displacement. A three-dimensional hydrodynamic model is used to simulate the flow characteristics during the passage of the rising limb of an observed hydropeaking event in a gravel-bed reach of Smith River, Virginia. The calculated time-dependent water surface elevations, velocities, and shear stresses are compared with field measurements. Further, comparison based on numerical simulations of this historical and a hypothetical “staggering” hydropeaking event reveals that the latter has the capability of reducing the area subject to erosion and prolonging refugia availability for juvenile brown trout. Issues related to the adoption of either a truly dynamic modeling approach or a quasi-steady methodology for simulating unsteady flows are examined through a proposed unsteadiness flow parameter. The insights obtained from this study can assist in properly accounting for the impact of hydropeaking operations on fish habitat and instream flow management.