Line Production

Maintenance management has a direct influence on production performance. Existing works have not systematically taken the on-line production information into consideration in determining maintenance work-order priority, which is often assigned either through an ad hoc approach or using largely heuristic and static methods. In this paper, we first present a metric that can be used to quantitatively evaluate the effects of different maintenance priorities. Based on this index, one can employ a search algorithm to obtain maintenance work-order priorities that will lead to improved productivity within the optimization horizon. These concepts and methods are validated through simulation experiments and implementation in a real industrial facility. The results show that the effective utilization of on-line production data in dynamic maintenance scheduling can yield visible production benefit through maintenance priority optimization.

On-line hemodiafiltration (HDF) has been introduced into clinical practice in the last few years. The most important technical and regulatory challenges were the safety and microbiological quality of ultrafiltrated substitution/replacement fluid. The application of ultrafilters in a different technical arrangement in the fluid path based on polysulfone or polyamide membranes should prevent patient contact with endotoxins and other pyrogenic or bacteria-derived substances. After resolving these problems and providing clinically safe and technically robust product solutions, increasing numbers of patients have been treated, especially those with severe clinical conditions, e.g., diabetes, hypo- or hypertension. The benefit for patients was brought about by the increase of substitution rate in hemodiafiltration and enhancing convective mass transfer. The impact of highly convective therapy modes on the state of immunomodulation towards the syndrome of microinflammation has not been investigated in a systematic prospective manner. In this study, 8 patients undergoing bag-HDF treatment with lactate buffered solution were investigated before online HDF treatment with commercially available whole blood stimulation assays testing for TNF-alpha and IL-6 release. Both assays are based on phytohemagglutinine (for TNF) and lipo-polysaccharide stimulation (for IL-6). Thereafter the patients were switched to on-line production of substitution fluid. After a wash-out period of 2 sessions the whole blood stimulation assays were applied to the same patients. The Wilcoxon test (for paired analysis) was done, revealing a statistically significant lower release of proinflammtory cytokines from patients' blood upon stimulation with PHA or LPS. The reduction of IL-6 and TNF concentration and release capacity in whole blood may be attributed to the use of high quality ultrapure substitution fluid and dialysate in on-line treatment instead of lactate buffer bag solution. These results indicate that not only an increase of convective mass tranfer by higher volume exchange, but also a decrease in unspecific activation of immunocompetent cells may have advantages for HDF-treated patients.

Three pure cultures of Xylaria polymorpha were isolated from fruiting bodies at yearly intervals over two years and maintained on 2% malt agar plates at room temperature. Immediately after isolation of the third culture, the cultures were inoculated onto sugar maple (Acer saccharum), aspen (Populus tremuloides), birch (Betula alleghaniensis), and basswood (Tilia americana) 14 mm cubes and incubated for 10 weeks in jars containing vermiculite. More zone lines were produced on aspen and sugar maple than on yellow birch or basswood. Increasing culture age generally caused a decrease in zone line production; however the effect was only statistically significant in sugar maple. The results indicate that aspen is preferable for zone line production with X. polymorpha, as both external and internal zone lines occur on this wood species, and zone line production remains high despite the age of the culture.

This paper proposes a design procedure of multi-item mixed-line production system in which various jigs, tools, capable facilities as well as skilled workers are equipped to enhance the capability of product variety. Major traditional technologies for the design of such production systems are classified into two categories, i.e. Line Balancing (LB) procedures which focus on balanced allocation of production resources, and Job Sequencing (JS) procedures which focus on balanced utilization of resources. In this paper, a conventional algorithm minimizing the number of stations is considered for the LB procedure, and an effective sequencing logic based on the ordinary Target Chasing Method (TCM) is proposed as a JS procedure for stable production as well as line stop aversion. Both of these procedures are integrated in terms of a two-stage hierarchical design procedure and its performance is investigated by simulation experiments under various conditions to ascertain its relevance.

Chronic renal failure and the uremic state lead to accumulation of various endogenous inhibitors of nitric oxide synthase. Previous studies on end-stage uremic patients nitric oxide synthase activity in murine vascular endothelium and cytokine-induced macrophage cell lines was shown to be modulated during treatment (Nephrol Dial Transplant 1995; 10: 1386-96). Paired filtration dialysis, a modified hemodiafiltration technique, physically separates convection from diffusion. Plasmas, ultrafiltrates and dialysates from seven uremic patients undergoing paired filtration dialysis performed using ultrapure apyrogen substitution fluid in the absence (first 120 min) or presence (last 120 min) of extracellular fluid reduction were tested for their inhibitory/stimulatory effect on ecNOS, constitutively expressed on t. End 1 cell line, a murine vascular endothelium, or for their inducing effect on iNOS, inducible on J774 cells, a macrophage cell line. On ecNOS, Group 1 (stimulatory, 3/7 patients) markedly enhanced the ecNOS activity as compared to control plasma, whereas group 2 plasma (inhibitory, 4/7 patients) inhibited ecNOS plasma. Post-dialysis plasma samples from all Group 1 and 2 patients showed a marked decrease of the predialysis stimulatory and inhibitory activity, respectively. On iNOS: all patient plasmas stimulated iNOS activity. The UF and particularly the dialysate had a remarkable iNOS inducing effect (Group 1). The substitution fluid obtained at 120 min during treatment in Group 1 and 2 had no effect on NOS activity. No correlation was found between predialysis ecNOS or iNOS activity values with mean systolic or diastolic pressures. These studies suggest a complex balance of ecNOS inhibitors/stimulators and iNOS inducers in uremia. Dialysis may remove ecNOS inhibitors and stimulators by convection and, in the latter case, by diffusion. iNOS inducers are removed during dialysis, suggesting the biocompatibility of the dialysis system with the on-line production of ultrapure substitution fluid.

X-ray production at about 6.8 keV by the 2p to 1s transition in fast hydrogen- and helium-like iron ions is calculated, following both electron capture to excited levels and collisional excitation. A refinement of the Oppenheimer-Brinkman-Kramers (1930) approximation is used to obtain an improved charge-exchange cross-section. This, and the corresponding ionization cross section, were used to determine equilibrium charge fractions for iron ions as functions of their energy. The effective X-ray line production cross section was found to be sharply peaked in energy at about 8 to 12 MeV per amu. Since fast ions of similar energies can also excite nuclear levels, the ratio of selected strong gamma-rays line emissivities to the X-ray line emissivity is calculated. These calculations are employed to set limits on the intensity of gamma-rays line emission from the galactic center and the radio galaxy Cen A, and it is found that these limits are generally lower than those reported in the literature.

Abstract Numerous techniques and algorithms have been developed for the analysis of production flow line systems. However, due to the complex nature of such systems, it is often possible to analyze only a small segment of the production line system at one time. When solution designs result from this analysis and are then implemented within the overall system, inefficient results can and frequently do occur. As such, an overall methodology is needed to analyze complex production line systems in their entirety. Q-GERT network modeling and simulation offers unique possibilities for this purpose. Q-GERT, a derivative of GERT network modeling, includes such features as probabilistic branching, network looping, multiple node realizations, and queue nodes which make it applicable to complex network forms such as production flow lines. In this paper Q-GERT is demonstrated as an appropriate vehicle for analysis via a detailed case example of a multi-product, multi-line production system. The production system is f...

[1] Interactions of galactic cosmic rays and solar energetic particles with nuclei in the Earth's atmosphere produce secondary neutrons. Secondary neutrons with energies greater than a few MeV interact with atmospheric nuclei and produce gamma ray lines. The relative intensities of these lines depend on the shape of the neutron energy spectrum, and so their measurement with satellite detectors provides neutron spectral information complementary to direct observation. Reliable interpretation of such line measurements requires accurate knowledge of the production cross sections. Because the atmospheric neutron spectrum at these energies is very hard (falling by less than a factor of 10 from 10 to 100 MeV), higher-energy neutrons contribute significantly to line production. Knowledge of the cross sections at these higher energies is critical for accurate line yield predictions. In this paper we evaluate and present the most important cross sections for deexcitation line production by neutron interactions with the Earth's atmosphere, with emphasis on extending them to higher neutron energies, using both laboratory measurements and the nuclear reaction code TALYS to obtain the cross sections from a few to >200 MeV. Using these cross sections, we also demonstrate the sensitivity of gamma ray line ratios for providing information about the ∼1–200 MeV atmospheric neutron spectrum.

Absenteeism among manual workers is without doubt one of the most significant factors that affect the functioning of assembly lines. It is a widely held view that high levels of absenteeism have negative repercussions on the quality and costs of operations. According to the scientific theory of work, workers who temporarily stand in for their absent colleagues affect production quality levels because of a lack of work specialization and experience. However, new and sophisticated automation can eliminate the effect of absenteeism on assembly line production. This article gathered more than 960,000 products produced by different levels of absenteeism. The effects of absenteeism on the quality of products in assembly lines over the course of one year were analyzed. In contrast to established thinking, the empirical evidence presented here confirms that absenteeism does not always produce problems in the quality of products. This evidence can be explained by the need for specialization among manual workers has been reduced by the invention of more sophisticated and specialized machinery. © 2007 Wiley Periodicals, Inc.

In this contribution a machine vision inspection system is presented which is designed as a length measuring sensor. It is developed to be applied to a range of heat shrink tubes, varying in length, diameter and color. The challenges of this task were the precision and accuracy demands as well as the real-time applicability of the entire approach since it should be realized in regular industrial line production. In production, heat shrink tubes are cut to specific sizes from a continuous tube. A multi-measurement strategy has been developed, which measures each individual tube segment several times with sub pixel accuracy while being in the visual field of a standard video camera. The developed approach allows for a contact-free and fully automatic control of 100% of produced heat shrink tubes according to the given requirements with a measuring precision of 0.1mm. Depending on the color, length and diameter of the tubes considered, a true positive rate of 99.99% to 100% has been reached at a true negative rate of > 99.7.