Optimization of Costs and Service Level by Choosing the Best Customer Order Decoupling Point

The customer order decoupling point (CODP) as the link in the supply chain between processes based on uncertain information, such as sales forecasts, and certain information in the form of customer orders is crucial for production efficiency, storage costs, and the quality of logistics. This paper focuses on developing an approach for identifying a CODP that provides the highest potential for achieving business objectives. Within the context of the above-mentioned topics, this paper focuses on the interrelations and the tradeoffs that have to be made when positioning the COPD. The goal of the paper is to present an effective and chronological sequence of tasks, analyses and methods, criteria, and indicators that can help a production planner determine the CODP. In the first part of the paper, the factors affecting the positioning of the CODP (internal and external to the company) and their characteristics are identified. Based on extensive literature research, these factors are then mapped to manufacturing concepts, such as make-to-stock, assemble-to-order, and make-to-order. The factors that lead to moving the CODP are also identified and used as the foundation for the development of an iterative procedural method with four stages. In stage 1, the as-is state and current goals are captured and suitable CODPs are identified for the above-mentioned logistic factors. In stage 2, the products are combined into groups to reduce the complexity of the analysis and a procedure for accomplishing this is proposed. The number of suitable CODPs is reduced in stage 3 and the factors that influence the positioning of CODPs are taken into consideration. In stage 4, a financial and qualitative evaluation is performed on the various CODPs

Development of a Heuristics for a Criteria Based Planning of Pallet Storage Systems

Reproducible and quantitative reasoning as the foundation for high-quality planning processes evolves to be key to achieve high quality of speed for logistical processes. This article strives to fulfill this demand by developing a coherent heuristics for the planning of pallet storage systems. The heuristics uses quantitative approaches provided by the available literature. In case of nonexistent sources, the missing components are developed and integrated. To be applicable in an industrial environment, the comparison and assessment of the created implementation alternatives is mainly monetary based. The heuristics follows a modular structure to achieve adaptability and extensibility. It explicitly does not intend to replace a human designer but to support him during the creation and assessment of high-quality design alternatives. A concluding case study evaluates the practical applicability of the heuristics and its created solutions. The review of the heuristics turns out to be positive. As a consequence, extension and improvement tasks are proposed

Axially-homogeneous Rayleigh-Benard convection in a cylindrical cell

Previous numerical studies have shown that the "ultimate regime of thermal convection" can be attained in a Rayleigh-Benard cell when the kinetic and thermal boundary layers are eliminated by replacing the walls with periodic boundary conditions (homogeneous Rayleigh-Benard convection). Then, the heat transfer scales like Nu ~ Ra^{1/2} and turbulence intensity as Re ~ Ra^{1/2}, where the Rayleigh number Ra indicates the strength of the driving force. However, experiments never operate in unbounded domains and it is important to understand how confinement might alter the approach to this ultimate regime. Here we consider homogeneous Rayleigh-Benard convection in a laterally confined geometry - a small aspect-ratio vertical cylindrical cell - and show evidence of the ultimate regime as Ra is increased: In spite of the confinement and the resulting kinetic boundary layers, we still find Nu ~ Re ~ Ra^{1/2}. The system supports exact solutions composed of modes of exponentially growing vertical velocity and temperature fields, with Ra as the critical parameter determining the properties of these modes. Counterintuitively, in the low Ra regime, or for very narrow cylinders, the numerical simulations are susceptible to these solutions which can dominate the dynamics and lead to very high and unsteady heat transfer. As Ra is increased, interaction between modes stabilizes the system, evidenced by the increasing homogeneity and reduced fluctuations in the r.m.s. velocity and temperature fields. We also test that physical results become independent of the periodicity length of the cylinder, a purely numerical parameter, as the aspect ratio is increased

Continuous Wave Terahertz Systems Based on 1.5 μm Telecom Technologies

Terahertz systems can profit from technologies developed originally for telecom applications. Recent developments on telecom-based key devices are summarized and ways towards CW systems with highest flexibility and excellent performance at reasonable costs are sketched

Effectivity of a mHealth intervention for individuals with obesity: a study protocol for a controlled intervention study

Background Obesity is considered an epidemic problem with an increasing number of individuals affected. The physical and psychological complaints associated with obesity point to the importance of implementing effective interventions. Innovative mHealth applications appear to be promising in helping provide a continuous and flexible support during the intervention. Since research on mHealth interventions is still relatively sparse, the main goal of the current study is to assess the effectiveness of an mHealth obesity intervention in terms of weight reduction, health behaviours as well as health-related quality of life. In addition, the study aims to investigate various psychological explicit and implicit processes associated with physical activity behaviour. Methods The study includes quantitative and qualitative methods. Regarding the quantitative methods, the goal is to recruit up to 450 individuals at baseline in different obesity centres across Germany with some of these centres offering an mHealth intervention. All individuals who agree to take part in the mHealth intervention will be assigned to the intervention group, while all other individuals will be assigned to the control group. The mHealth obesity intervention consists of three stays at an obesity centre, with approximately six months between stays during which patients are supported by the digital platform CASPAR. The study includes three measurements with a baseline measurement and two follow-up measurements, one after six months and one after twelve months. To assess the effectiveness of the intervention, body weight, physical activity behaviour, eating behaviour as well as health related quality of life will be assessed. In addition, motivation, intentions, self-efficacy, enjoyment, and habit will be used to assess the psychological processes related with physical activity behaviour. A multivariate analysis of variance with repeated measurement and latent growth curve models will be used to compare the development of the variables within the two groups. In relation to the qualitative methods, interviews with individuals of the intervention group will be conducted to shed light on the applicability, acceptance, and usability of the mHealth intervention. Discussion This study may provide a valuable insight into the potential of mHealth obesity interventions and the psychological processes related to physical activity behaviour

Ultrafiltration conducting membranes and coatings from redispersable, nanoscaled, crystalline SnO2:Sb particles

Inorganic membranes prepared by the sol-gel method are promising candidates for use as filters in separation processes. Conducting supported membranes and coatings have been produced from redispersable nanoscaled crystalline Sb-doped SnO2 powders with Sb contents up to 10 mol%. The crystalline particles (ca. 4 nm) are fully redispersable in aqueous solution at ph ≥ 8 with a solid content up to 37 vol.% and are monosized. After thermal treatment at different temperatures and times, the pore size diameter of such a powder can be adjusted from 4-20 nm with a very narrow pore size distribution (ca. ±1 nm) and a total porosity of 63%, practically independent of the sintering parameters. Uniaxial compacted substrates (unsupported membranes) present similar characteristics but with a larger pore size distribution (± 5 nm) and 80% total porosity. Their electrical resistance decreases with sintering temperature and time to 4 Ω (800 °C, 8 h). Crack free transparent conducting coatings on glasses and ceramics have been obtained by spin-coating using fully dispersed aqueous solutions of the powder with volume content up to 7.8%. After thermal treatment (1 h at 550 °C) single layers 200 nm thick are still porous and exhibit specific electrical resistivity as low as p = 2.5 x 10-2 Ω cm with 90% transmission in the visible range

Element Partitioning between Immiscible Carbonatite and Silicate Melts for Dry and H2O-bearing Systems at 1-3 GPa

Carbonatite and silicate rocks occurring within a single magmatic complex may originate through liquid immiscibility. We thus experimentally determined carbonatite/silicate melt partition coefficients (Dcarbonate melt/silicate melt, hereafter D) for 45 elements to understand their systematics as a function of melt composition and to provide a tool for identifying the possible conjugate nature of silicate and carbonatite magmas. Static and, when necessary, centrifuging piston cylinder experiments were performed at 1-3 GPa, 1150-1260°C such that two well-separated melts resulted. Bulk compositions had Na K, Na ∼ K, and Na K; for the latter we also varied bulk H2O (0-4 wt %) and SiO2 contents. Oxygen fugacities were between iron-wüstite and slightly below hematite-magnetite and were not found to exert significant control on partitioning. Under dry conditions alkali and alkaline earth elements partition into the carbonatite melt, as did Mo and P (DMo >8, DP= 1·6-3·3). High field strength elements (HFSE) prefer the silicate melt, most strongly Hf (DHf = 0·04). The REE have partition coefficients around unity with DLa/Lu = 1·6-2·3. Transition metals have D < 1 except for Cu and V (DCu ∼ 1·3, DV = 0·95-2). The small variability of the partition coefficients in all dry experiments can be explained by a comparable width of the miscibility gap, which appears to be flat-topped in our dry bulk compositions. For all carbonatite and silicate melts, Nb/Ta and Zr/Hf fractionate by factors of 1·3-3·0, in most cases much more strongly than in silicate-oxide systems. With the exception of the alkalis, partition coefficients for the H2O-bearing systems are similar to those for the anhydrous ones, but are shifted in favour of the carbonatite melt by up to an order of magnitude. An increase of bulk silica and thus SiO2 in the silicate melt (from 35 to 69 wt %) has a similar effect. Two types of trace element partitioning with changing melt composition can be observed. The magnitude of the partition coefficients increases for the alkalis and alkaline earths with the width of the miscibility gap, whereas partition coefficients for the REE shift by almost two orders of magnitude from partitioning into the silicate melt (DLa = 0·47) to strongly partitioning into the carbonatite melt (DLa = 38), whereas DLa/DLu varies by only a factor of three. The partitioning behavior can be rationalized as a function of ionic potential (Z/r). Alkali and alkaline earth elements follow a trend, the slope of which depends on the K/Na ratio and H2O content. Contrasting the sodic and potassic systems, alkalis have a positive correlation in D vs Z/r space in the potassic case and Cs to K partition into the silicate melt in the presence of H2O. For the divalent third row transition metals on the one hand and for the tri- and tetravalent REE and HFSE on the other, two trends of negative correlation of D vs Z/r can be defined. Nevertheless, the highest ionic strength network-modifying cations (V, Nb, Ta, Ti and Mo) do not follow any trend; understanding their behavior would require knowledge of their bonding environment in the carbonatite melt. Strong partitioning of REE into the carbonatite melt (DREE = 5·8-38·0) occurs only in H2O-rich compositions for which carbonatites unmix from evolved alkaline melts with the conjugate silicate melt being siliceous. We thus speculate that upon hydrous carbonatite crystallization, the consequent saturation in fluids may lead to hydrothermal systems concentrating REE in secondary deposit

Modeling Hydrogen Networks for Future Energy Systems: A Comparison of Linear and Nonlinear Approaches

Common energy system models that integrate hydrogen transport in pipelines typically simplify fluid flow models and reduce the network size in order to achieve solutions quickly. This contribution analyzes two different types of pipeline network topologies (namely, star and tree networks) and two different fluid flow models (linear and nonlinear) for a given hydrogen capacity scenario of electrical reconversion in Germany to analyze the impact of these simplifications. For each network topology, robust demand and supply scenarios are generated. The results show that a simplified topology, as well as the consideration of detailed fluid flow, could heavily influence the total pipeline investment costs. For the given capacity scenario, an overall cost reduction of the pipeline costs of 37% is observed for the star network with linear cost compared to the tree network with nonlinear fluid flow. The impact of these improvements regarding the total electricity reconversion costs has led to a cost reduction of 1.4%, which is fairly small. Therefore, the integration of nonlinearities into energy system optimization models is not recommended due to their high computational burden. However, the applied method for generating robust demand and supply scenarios improved the credibility and robustness of the network topology, while the simplified fluid flow consideration can lead to infeasibilities. Thus, we suggest the utilization of the nonlinear model for post-processing to prove the feasibility of the results and strengthen their credibility, while retaining the computational performance of linear modeling