Compositional heterogeneity may limit the usefulness of some commercial naphthenic acids for toxicity assays

Naphthenic acids are considered variously as monocarboxylic acids fitting the formula C_nH_2n + zO₂ (where z is a zero or negative even integer), as only alicyclic (i.e. non-aromatic) monocarboxylic acids fitting this formula (z ≤ 0), or simply as those carboxylic acids occurring in petroleum products or crude oils that have been formed through biodegradation of hydrocarbons. Such acids are known constituents of the process-affected water associated with some expanding oil sands industries, of some immature and biodegraded crude oils, of produced water discharges from oil production platforms and are used as biocides and as components in the manufacture of steel radial tyres.As a result of these potential vectors of the acids into the environment, various naphthenic acid mixtures which are available commercially have been used for a range of toxicity studies. However, as some manufacturers make clear, but which is not often emphasised in the toxicity studies, a range of different quality naphthenic acids is produced commercially. It has been suggested previously, and we showed recently and elucidate further herein, that such commercial mixtures therefore sometimes contain toxic components other than carboxylic acids. For example, we identify herein by two-dimensional comprehensive gas chromatography-mass spectrometry, a range of C_0-6 alkylphenols in a batch of commercial naphthenic acids. Since these compounds are known toxicants, the contribution of such non-carboxylic acids, if any, to the toxicity attributed previously to the acids, should also be considered. This will be reflected in the concentrations and effective toxicities of such components. In order to establish the toxicity of the acids per se, assays of pure synthetic carboxylic acids of the type now known to be present in naphthenic acids from petroleum or oil sands may be more appropriate than tests of the toxicity of largely unknown, heterogeneous, mixtures.     

A balanced design procedure for special concentrically braced frame connections

Concentrically braced frames (CBFs) are stiff, strong structures that are suitable for resisting large lateral loads. Special CBFs (SCBF) are used for seismic design and are designed and detailed to sustain relatively large inelastic deformations without significant deterioration in resistance. Current AISC Seismic Design Provisions aim to ensure the brace sustains the required inelastic action, but recent research showed that current SCBF design requirements lead to variable seismic performance, unintended failure modes, and limited deformation capacity. To improve the seismic response of SCBFs, a balanced design procedure was proposed. The premise of the design methodology is to balance the primary yield mechanism, brace buckling and yielding, with other, complementary ductile yielding mechanisms, such as gusset plate yielding. This balance process maximizes ductile yielding in the frame thereby maximizing the drift capacity of the frame. Further, the undesirable failure modes are balanced with the yield mechanisms and the preferred failure mode, brace fracture, to ensure that the frame fails in the desired manner. To achieve the objectives of the design methodology namely maximum drift capacity, and adherence to a desired yield and failure hierarchy, rational resistance checks and appropriate balance factors (β factors) are used to balance each yield mechanism and failure mode. These factors were developed, validated, and refined using the measured results from an extensive test program. An SCBF connection design example to illustrate the application of the balanced design method and to demonstrate differences from the current AISC design method is presented in an appendix.     

In Situ Study of Nanostructure and Electrical Resistance of Nanocluster Films Irradiated with Ion Beams

An in situ study is reported on the structural evolution in nanocluster films under He⁺ ion irradiation using an advanced helium ion microscope. The films consist of loosely interconnected nanoclusters of magnetite or iron‐magnetite (Fe‐Fe₃O₄) core‐shells. The nanostructure is observed to undergo dramatic changes under ion‐beam irradiation, featuring grain growth, phase transition, particle aggregation, and formation of nanowire‐like network and nanopores. Studies based on ion irradiation, thermal annealing and electron irradiation have indicated that the major structural evolution is activated by elastic nuclear collisions, while both electronic and thermal processes can play a significant role once the evolution starts. The electrical resistance of the Fe‐Fe₃O₄ films measured in situ exhibits a super‐exponential decay with dose. The behavior suggests that the nanocluster films possess an intrinsic merit for development of an advanced online monitor for fast neutron radiation with both high detection sensitivity and long‐term applicability, which can enhance safety measures in many nuclear operations.     

Chemical recovery of surface waters across the northeastern united states from reduced inputs of acidic deposition: 1984-2001

Changes in lake water chemistry between 1984 and 2001 at 130 stratified random sites across the northeastern United States were studied to evaluate the population-level effects of decreases in acidic deposition. Surface-water S04(2-) concentrations decreased across the region at a median rate of -1.53 microequiv L(-1) year(-1). Calcium concentrations also decreased, with a median rate of -1.73 microequiv L(-1) year(-1). This decrease in Ca2+ retarded the recovery of surface water acid neutralizing capacity (Gran ANC), which increased at a median rate of 0.66 microequiv L(-1) year(-1). There were small increases in pH in all subregions except central New England and Maine, where the changes were not statistically significant. Median NO3- trends were not significant except in the Adirondacks, where NO3- concentrations increased at a rate of 0.53 microequiv L(-1) year(-1). A regionwide decrease in the concentration of total Al, especially in ponds with low ANC values (ANC < 25 microequiv L(-1)), was observed in the Adirondack subregion. These changes in Al were consistent with the general pattern of increasing pH and ANC. Despite the general pattern of chemical recovery, many ponds remain chronically acidic or are susceptible to episodic acidification. The continued chemical and biological recovery at sites in the northeastern United States will depend on further controls on S and N emissions.     

Removal of heavy metals from aqueous systems with thiol functionalized superparamagnetic nanoparticles

We have shown that superparamagnetic iron oxide (Fe3O4) nanoparticles with a surface functionalization of dimercaptosuccinic acid (DMSA) are an effective sorbent material for toxic soft metals such as Hg, Ag, Pb, Cd, and Tl, which effectively bind to the DMSA ligands and for As, which binds to the iron oxide lattices. The nanoparticles are highly dispersible and stable in solutions, have a large surface area (114 m2/g), and have a high functional group content (1.8 mmol thiols/g). They are attracted to a magnetic field and can be separated from solution within a minute with a 1.2 T magnet. The chemical affinity, capacity, kinetics, and stability of the magnetic nanoparticles were compared to those of conventional resin based sorbents (GT-73), activated carbon, and nanoporous silica (SAMMS) of similar surface chemistries in river water, groundwater, seawater, and human blood and plasma. DMSA-Fe3O4 had a capacity of 227 mg of Hg/g, a 30-fold larger value than GT-73. The nanoparticles removed 99 wt% of 1 mg/L Pb within a minute, while it took over 10 and 120 min for Chelex-100 and GT-73 to remove 96% of Pb.     

Coordinated Control Architecture for Motion Management in ADAS Systems

Advanced driver assistance systems (ADAS) seek to provide drivers and passengers of automotive vehicles increased safety and comfort. Original equipment manufacturers are integrating and developing systems for distance keeping, lane keeping and changing and other functionalities. The modern automobile is a complex system of systems. How the functionalities of advanced driver assistance are implemented and coordinated across the systems of the vehicle is generally not made available to the wider research community by the developers and manufactures. This paper seeks to begin filling this gap by assembling open source physics models of the vehicle dynamics and ADAS command models. Additionally, in order to facilitate ADAS development and testing without having access to the details of ADAS, a coordinated control architecture for motion management is also proposed for distributing ADAS motion control commands over vehicle systems. The architecture is demonstrated in a case study where motion is coordinated between the steering and the braking systems, which are typically used only for a single functionality. The integrated vehicle and system dynamics using the coordinated control architecture are simulated for various driving tasks. It is seen that improved trajectory following can be achieved by the proposed coordinated control architecture. The models, simulations and control architecture are made available for open access.      

Rolling Mill Reel Drives

During the past few years there has been significant progress in the technology and hardware available to the electrical engineer. Accordingly, drive capabilities and limitations have changed, justifying a restating of application criteria pertaining to reel drives. As an aid in specifying and utilizing reel drives, this paper discusses application techniques and guides based on today's technology.     

The effect of fat on the gastric responses to foods

Summary 1. In eight series of triplicate tests on persons in good health and with normal secretory responses who were fed test meals of foods cooked with fat, the day to day variations in gastric evacuation times ranged from 0 to 30 minutes with an average deviation from the mean of ±17 minutes. 2. Experiments with meals of foods in which moderate quantities of fats were incorporated intimately by either baking or frying according to good culinary procedure revealed no relationship between the fat contents of the foods and the times required for complete evacuation of the foods from the subjects’ stomachs. 3. The experiments indicated a parallelism between the protein contents of the test meals and the gastric evacuation times. 4. No significant differences were observed between the influences of a hydrogenated vegetable fat and of butter upon the rates of evacuation from the subjects’ stomachs of meals of potatoes in which these fats had been incorporated intimately by good culinary technic. Within the limits of error of the experimental procedure, French fried and Lyonnaise potatoes containing moderate amounts of fat were evacuated from the stomachs as rapidly as boiled potatoes. 5. Gastric emptying times for meals of doughnuts did not differ significantly from gastric evacuation times for meals of bread and butter supplying equivalent amounts of fat. 6. The addition to a test meal of glucose in water of either hydrogenated vegetable fat or butter fat in amounts equivalent to two-thirds the weight of the glucose retarded the evacuation of the glucose meal from the stomach. 7. Excess fat, added to potatoes by pan-frying in hydrogenated vegetable fat or butter to the extent of making the potatoes “greasy,” such as may occur in poor culinary practice, prolonged the emptying time of the stomach beyond the period for boiled potatoes. 8. An explanation has been suggested for this retardation of the emptying of the stomach effected both by digestible fats added to glucose solutions and by foods containing fats in excess of that which is incorporated intimately in these foods by good culinary methods. This paper was presented before the meeting of the American Oil Chemists’ Society, Chicago, Illinois, October 27, 1944. This work was supported by a grant from Lever Brothers Company, Cambridge, Massachusetts.     

Some observations on the determination of soap in refined oil

Recovery experiments which were made by two quite different procedures indicate that the most satisfactory approach to a solution of the problem of determining the soap content of a refined oil probably rests upon the assumption that the chloride which is formed upon the addition of hydrochloric acid is an index of the quantity present. At soap concentrations of 100 pts/M² and less, the Durst method, as modified by Stillman, was found to be quantitative for all practical purposes.