A divide-and-conquer approach for analysing overlaid data structures

We present a static program analysis for overlaid data structures such that a node in the structure includes links for multiple data structures and these links are intended to be used at the same time. These overlaid data structures are frequently used in systems code, in order to impose multiple types of indexing structures over the same set of nodes. Our analysis implements two main ideas. The first is to run multiple sub-analyses that track information about non-overlaid data structures, such as lists. The second idea is to control the communication among the sub-analyses using ghost states and ghost instructions. The purpose of this control is to achieve a high level of efficiency by allowing only necessary information to be transferred among sub-analyses and at as few program points as possible. Our analysis has been successfully applied to prove the memory safety of the Linux deadline IO scheduler and AFS server.     

Robust performance analysis for uncertain negative‐imaginary systems

Negative‐imaginary systems are important in engineering practice as this class of systems appears quite often in practical problems, for example, lightly damped flexible structures with collocated position sensors and force actuators. In this paper, an analytical framework for robust performance of uncertain negative‐imaginary systems is proposed. The results are obtained by transforming negative‐imaginary systems into a bounded‐real framework via the positive‐real property. This paper deals with all the significant technical difficulties that appear due to the transformation and the punctured j ω‐axis frequency condition of negative‐imaginary systems. The problem is equivalently cast into a structured singular value condition that gives a quantitative performance test for this class of systems. This result also gives an analytical framework for robust stability when the perturbations are mixture of bounded‐real and negative‐imaginary uncertainties. A numerical example is presented to show the usefulness of the proposed methods. Copyright © 2011 John Wiley & Sons, Ltd.     

Capacity management under uncertainty with inter-process, intra-process and demand interdependencies in high-flexibility environments

In this paper, we develop models for capacity planning within the framework of stochastic processing times and stochastic demand for different process outcomes in high-flexibility environments. We particularly address stochastic interdependencies between processing times for different processes (inter-process correlation), interdependencies between the capacity consumption (task times) of different executions of the same task in a given production stage (intra-process correlation) as well as interdependencies between the demand for different process outcomes. After presenting the base model, we conduct extensive sensitivity analyses and analyze the main relationships between different model variables. We use process and demand data from the financial industry to demonstrate the applicability and relevance of our findings.     

Engineering model for intumescent coating behavior in a pilot‐scale gas‐fired furnace

In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literature for several decades. However, various challenges still exist. The most important one concerns mathematical model validation under realistic exposure conditions and/or time scales. Another is the simplification of advanced models to overcome the often‐seen lack of a complete set of input and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m³ gas‐fired furnace, heating up according to so‐called cellulosic fire conditions, were conducted and a very good repeatability was evident. The experiments were run for almost 3 h, reaching a final gas temperature of about 1100°C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3947–3962, 2016     

Formation of cavities in GaAs and InGaAs

The ion implantation of He is examined as a means to form thermally stable cavities in GaAs. Room-temperature implantation of 2–10 × 10¹⁶ He/cm² at 40 or 50 keV forms bubbles, but subsequent annealing at 250°C or above leads to exfoliation of the implanted surface layer. The exfoliation appears related to the agglomeration of bubbles on dislocations at the back of the layer; evidence suggests these may be misfit dislocations formed to relieve compressive stress in the implanted layer. Implantation of He at 150°C produces similar results, whereas the He diffuses out of GaAs without forming cavities during implantation at 300°C. However, implantations of immobile Ar followed by He at 400°C produce extended defects with bubbles in the implanted layer; the He can be degassed by subsequent annealing at 400°C to produce 1.5–3.5 nm cavities that are stable at this temperature. The same treatment applied to an In_0.10Ga_0.90As/GaAs heterostructure produces larger cavities preferentially located on dislocations at the interface, with only slight reduction in strain of the epitaxial layer. The microstructures of both GaAs and the heterostructure clearly demonstrate an attractive interaction between bubbles or cavities and dislocations.     

污泥作为污水厂内碳源的水解特性及工艺选择

随着各地污水厂出水水质对氮、磷要求的日益提高,强化脱氮除磷成为必然要求,但是我国多数污水厂由于多种原因导致进水碳源不足,尤其是进水SCOD、VFAs的匮乏,直接影响了生物脱氮除磷的效率,甚至不得已采用人工投加外碳源脱氮或者化学除磷方式以满足严格的出水氮、磷要求,但这无疑大大提高了污水厂的产泥率及运行成本.充分挖掘污水厂的“内碳源”,利用污泥水解产生VFAs,不仅能有效提高除磷脱氮效率,而且可以降低污水厂的污泥产量,是可持续的资源化技术.比较了初沉污泥和活性污泥的水解特性差异,介绍了污泥水解工艺的常用构型及参数选择,以及国内外一些成功的实施案例.     

Migration of formaldehyde and melamine monomers from kitchen- and tableware made of melamine plastic

Migration of one or both formaldehyde and/or melamine monomers was found in seven of ten tested melamine samples bought on the Danish market. The samples were a bowl, a jug, a mug, a ladle, and different cups and plates. No violation of the European Union-specific migration limits for melamine (30 mg kg^-1) and formaldehyde (15 mg kg^-1) was found after three successive exposures to the food stimulant 3% acetic acid after 2 h at 70°C. To investigate the effects of long-term use, migration tests were performed with two types of cups from a day nursery. Furthermore, medium-term use was studied by ten successive exposures of a plate to 3% acetic acid for 30 min at 95°C. The results indicate that continuous migration of formaldehyde and melamine takes place during the lifetime of these articles. The molar ratio of released formaldehyde to melamine was seen to decrease from 12 to about 5. This indicates that, first, the migration of residual monomers is most important, but in the long-term, breakdown of the polymer dominates. Two CEN methods were used to determine the concentration of monomers: a spectrophotometric method for formaldehyde and a UV-HPLC method for melamine.     

Peanut varieties with reduced Ara h 1 content indicating no reduced allergenicity

Peanut allergy is a major cause of food‐induced severe anaphylactic reactions. To date, no medical care is available to prevent and treat peanut allergy and therefore hypoallergenic peanut varieties are of considerable health political and economic interest. Major allergens that induce IgE‐responses in peanut‐sensitive patients are Ara h 1, Ara h 2 and Ara h 3/4. In order to identify hypoallergenic peanuts, commercially locally available peanut varieties were screened for their allergen content. Ara h 1‐deficient peanuts from Southeast Asia were identified by SDS‐PAGE, immunoblotting, inhibition assays and ELISA. 2‐D PAGE analyses demonstrated the different compositions of the tested extracts and revealed a number of variations of the allergen patterns of peanuts from different varieties. Mediator release experiments of these peanut extracts demonstrated similar allergenicities as compared with standard peanut extract. These results indicate that the allergenicity of peanuts with reduced Ara h 1 content might be compensated by the other allergens, and thus do not necessarily cause a reduction of allergenicity.