Reflections on the evolution of implicit Navier–Stokes algorithms

This article gives a historical perspective on the evolution of implicit algorithms for the Navier–Stokes equations that utilize time or Newton linearizations and various forms of approximate factorization including alternating-direction, lower/upper, and symmetric relaxation schemes. A theme of the paper is how progress in implicit Navier–Stokes algorithms has been influenced and enabled by the introduction of characteristic-based upwind approximations, unstructured-grid discretizations, parallelization, and by advances in computer performance and architecture. Historical examples of runtime, problem size, and estimated cost are given for actual and hypothetical Navier–Stokes flow cases from the past 40 years.     

Classification of abnormal plant operation using multiple process variable trends

This paper illustrates two strategies for the detection and classification of abnormal process operating conditions in which multiple process variable trends are available. The first strategy uses a hidden Markov model (HMM) for overall process classification while the second method uses a back-propagation neural network (BPNN) to determine the overall process classification. The methods are compared in terms of their ability to detect and correctly diagnose a variety of abnormal operating conditions for a non-isothermal CSTR simulation. For the case study problem, the BPNN method resulted in better classification accuracy with a moderate increase in training time compared with the HMM approach.     

Adaptation of thermafil components to canal walls

In summer 1991 an outbreak of a Salmonella enteritidis epidemic involving about 600 cases of gastroenteritis occurred at one of the leading pharmaceutical companies in southwestern Germany. The main source was a cold fruit soup, in addition Salmonella were isolated from meat strips and a curd cheese which were used for a salad dressing. A total of 2300 contaminated food portions were served resulting in an attack rate of about 25%. The possible origin could have been an asymptomatic Salmonella-positive member of the kitchen personnel who was the only one who was involved with the preparation of all the incriminated foods. A further spread of the epidemic and especially the possible contamination of pharmaceuticals was avoided by the timely and adequate reaction of the company's occupational medical service. This case exemplifies how classical crisis management, "increased initiative on one's own for prevention of infections in all areas of food processing" (Steuer) and finally the cooperation of the company with different institutions of the public health authorities contribute to the control of such a catastrophic scenario.     

A technique for developing and photographing ridge impressions on decomposed water-soaked fingers

One of the most challenging tasks confronting a crime laboratory technician is the fingerprinting and subsequent identification of an unknown homicide or drowning victim whose fingers have been subjected to a long period of exposure to water and the effects of decomposition. If the fingers of the individual have not been exposed to the erosive effects of water and decomposition for a long period of time, they may be allowed to dry, and suitable impressions are often obtainable. In other cases the fingers may have to be removed, with the permission of the Medical Examiners Office, and processed by the Crime Laboratory in an attempt to develop suitable ridge structure for inked impressions or an exact photographic copy of the individual's fingers. In extreme cases the effects of water and decomposition make the fragile ridge structure appear to be nonexistent to the naked eye. The procedure used in this case report, combines the use of cyanoacrylate vapor, commonly called "super glue fuming," and the ninhydrin process in conjunction to develop fragile ridge structure into discernable ridges that are easily seen and photographed for the purpose of making an identification of the individual.     

Habituation of the orienting response: a gating mechanism subserving selective attention

Possibilities of involution of changes in lesser circulation after closure of experimental aortopulmonary anastomosis were studied. 37 observations at various intervals after closure of anastomosis (several minutes to 13.5 months) in 25 dogs were analyzed. Before closure the anastomosis had functioned for 1-7 months. The results of histological examinations of lungs, pressure measurements in lesser circulation, heart weight, electrocardiographic and spirographic examinations were analyzed. It was found that complete involution of changes in lesser circulation was possible only in first month of existence of anastomosis, in this case with changes of both "early" and "late" types. "Late"-type changes after four months function of anastomosis had both reversible and irreversible character, whereas "early"-type changes became irreversible already after three-month duration of anastomosis. With the "late"-type changes, the operation itself (closure of anastomosis) was accompanied by symptoms of pulmonary vasomotor paresis and heart failure, whereas in the presence of "early"-type changes the operation elicited no morphological or functional changes.     

Immunogestosis: a new etiologic concept of "essential" EPH gestosis, with special consideration of the primigravid patient; preliminary report of a clinical study

Evidence for immunologic processes taking part in the pathogenesis of what until now has been called the "essential" form of EPH gestosis is cited. The name of immunogestosis (IG) is introduced. The data of this preliminary study suggest that regular "inoculation" of the female genital tract with allogeneic spermatozoal histocompatibility antigens reduces the incidence of IG. Information about preconceptional sexual habits and contraceptive measures was obtained from 83 selected primigravid patients. Twenty-eight women had mild to moderate IG (Group B);55 did not (Group A). Women in Group B had had less contact with spermatozoa of partners than did women in Group A. Oral contraceptive consumption was less in Group B than in Group A. Women in Group B were younger than women in Group A. All these differences were statistically significant. A new immunoetiologic hypothesis referring to IG, as well as the theoretic and clinical implications arising from it, are discussed. This hypothesis is based on the assumption that spermatozoal histocompatibility antigens can either induce immunologic tolerance or be responsible for the phenomenon of immunologic enhancement in the maternal immunosystem. As the fetus inherits paternal histocompatibility antigens, it is concluded that pre-existing tolerance (or enhancement) exerts an IG-preventive function in a subsequent pregnancy.     

DIIS: A cross-platform program for the reduction of X-ray diffraction data from a cylindrical area detector

A new program capable of rapidly and accurately reducing a two-dimensional X-ray diffraction pattern obtained from a Debye-Scherrer or Gandolfi camera to a quantitative digital diffractogram is described. By implementing geometric optimization routines based on the symmetry and sharpness of diffraction lines, the optimal configuration of the camera, X-ray path, and sample can be determined, thus providing the best possible set of integration parameters. Results for NIST standard reference materials 640c (Si) and 676 (Al₂O₃) are included to illustrate program functionality.