Modelling of a rope-free passenger transportation system for active cabin vibration damping

Conventional vertical passenger transportation is performed by lifts. Conventional traction-drive electrical lifts use ropes to transfer the rotational motion of an electrical motor into a vertical motion of the cabin. The vertical passenger transportation system discussed in this paper does not use any ropes, the motor directly provides a driving force, which moves the cabin. This new propulsion is realized through an electrical linear motor. The use of the linear motor requires a new design of the passenger transportation system (PTS), which includes reducing the weight of the car through lightweight construction. The reduced stiffness of the lightweight design renders the construction more vulnerable to vibrations. In order to improve ride quality of the transportation system it is necessary to develop new concepts to damp the vibrations. One way to increase stiffness characteristics of the system is to introduce active damping components to be used alongside passive damping components. It is essential to derive a dynamic model of the system in order to design and also later control these damping components in the best possible way. This paper describes the fundamental steps undertaken to derive a dynamic model for designing and controlling active damping components for the new type of vertical PTS. The model is derived as a Multi-Body System (MBS), where the connections between the bodies are modelled as spring damper elements. The derivation of the MBS is demonstrated on a transportation system, consisting of three main components: a sledge, holding the rotor of the linear motor; a mounting frame, which is used to provide support for the cabin; and the actual cabin. The modelling of the propulsion system, thus the electrical part of the PTS, will not be the focus of this work

Key Dynamic Parameters that Influence Ride Quality of Passenger Transportation Systems

Ride quality is a measure of the comfort level experienced by passengers and is intimately associated with their subjective perception and sensitivity to motion and to sound. This measure is affected by noise and vibration of a running system. On the other hand, ride quality is the measure of the product quality of a Passenger Transportation System (PTS) manufacturer. Ride quality of passenger transportation systems is critical for a PTS manufacturer to determine the subjective and objective quality of PTS. This is especially important in high rise (high end) systems. The paper investigates the dynamic interaction of PTS system components and their influence on ride quality

IFN-γ-Based ELISpot as a New Tool to Detect Human Infections with Borna Disease Virus 1 (BoDV-1): A Pilot Study

More than 40 human infections with the zoonotic Borna disease virus 1 (BoDV-1) have been reported to German health authorities from endemic regions in southern and eastern Germany. Diagnosis of a confirmed case is based on the detection of BoDV-1 RNA or BoDV-1 antigen. In parallel, serological assays such as ELISA, immunoblots, and indirect immunofluorescence are in use to detect the seroconversion of Borna virus-reactive IgG in serum or cerebrospinal fluid (CSF). As immunopathogenesis in BoDV-1 encephalitis appears to be driven by T cells, we addressed the question of whether an IFN-γ-based ELISpot may further corroborate the diagnosis. For three of seven BoDV-1-infected patients, peripheral blood mononuclear cells (PBMC) with sufficient quantity and viability were retrieved. For all three patients, counts in the range from 12 to 20 spot forming units (SFU) per 250,000 cells were detected upon the stimulation of PBMC with a peptide pool covering the nucleocapsid protein of BoDV-1. Additionally, individual patients had elevated SFU upon stimulation with a peptide pool covering X or phosphoprotein. Healthy blood donors (n = 30) and transplant recipients (n = 27) were used as a control and validation cohort, respectively. In this pilot study, the BoDV-1 ELISpot detected cellular immune responses in human patients with BoDV-1 infection. Its role as a helpful diagnostic tool needs further investigation in patients with BoDV-1 encephalitis

Human Infections with Borna Disease Virus 1 (BoDV-1) Primarily Lead to Severe Encephalitis: Further Evidence from the Seroepidemiological BoSOT Study in an Endemic Region in Southern Germany

More than 40 human cases of severe encephalitis caused by Borna disease virus 1 (BoDV-1) have been reported to German health authorities. In an endemic region in southern Germany, we conducted the seroepidemiological BoSOT study (“BoDV-1 after solid-organ transplantation”) to assess whether there are undetected oligo- or asymptomatic courses of infection. A total of 216 healthy blood donors and 280 outpatients after solid organ transplantation were screened by a recombinant BoDV-1 ELISA followed by an indirect immunofluorescence assay (iIFA) as confirmatory test. For comparison, 288 serum and 258 cerebrospinal fluid (CSF) samples with a request for tick-borne encephalitis (TBE) diagnostics were analyzed for BoDV-1 infections. ELISA screening reactivity rates ranged from 3.5% to 18.6% depending on the cohort and the used ELISA antigen, but only one sample of a patient from the cohort with requested TBE diagnostics was confirmed to be positive for anti-BoDV-1-IgG by iIFA. In addition, the corresponding CSF sample of this patient with a three-week history of severe neurological disease tested positive for BoDV-1 RNA. Due to the iIFA results, all other results were interpreted as false-reactive in the ELISA screening. By linear serological epitope mapping, cross-reactions with human and bacterial proteins were identified as possible underlying mechanism for the false-reactive ELISA screening results. In conclusion, no oligo- or asymptomatic infections were detected in the studied cohorts. Serological tests based on a single recombinant BoDV-1 antigen should be interpreted with caution, and an iIFA should always be performed in addition

The Empirics of Agglomeration Economies

We propose an integrated framework to discuss the empirical literature on the local determinants of agglomeration effects. We start by presenting the theoretical mechanisms that ground individual and aggregate empirical specifications. We gradually introduce static effects, dynamic effects, and workers' endogenous location choices. We emphasise the impact of local density on productivity but we also consider many other local determinants supported by theory. Empirical issues are then addressed. Most important concerns are about endogeneity at the local and individual levels, the choice of a productivity measure between wage and TFP, and the roles of spatial scale, firms' characteristics, and functional forms. Estimated impacts of local determinants of productivity, employment, and firms' locations choices are surveyed for both developed and developing economies. We finally provide a discussion of attempts to identify and quantify specific agglomeration mechanisms

Key dynamic parameters that influence ride quality of passenger transportation systems

Ride quality is a measure of the comfort level experienced by passengers and is intimately associated with their subjective perception and sensitivity to motion and to sound. This measure is affected by noise and vibration of a running system. On the other hand, ride quality is the measure of the product quality of a Passenger Transportation System (PTS) manufacturer. Ride quality of passenger transportation systems is critical for a PTS manufacturer to determine the subjective and objective quality of PTS. This is especially important in high rise (high end) systems. The paper investigates the dynamic interaction of PTS system components and their influence on ride quality

An analysis of airflow effects in lift systems

The current trends towards the design of lighter cars for high-speed lift systems and multiple car lift systems have encouraged the design of more aerodynamic efficient car geometries. Lighter lift cars are susceptible to aerodynamic drags and piston effects. The issue of piston phenomena affecting smoke control in traditional lift shaft configurations have been studied extensively. Considering the complexity of multiple car, multidirectional shafts and the susceptibility of lighter cars to aerodynamic drag and piston effects, it is important that relevant analysis is developed to determine the aerodynamic effects arising in those systems. With advances in the field of Computational Fluid Dynamics (CFD), it is now possible to compute 3D compressible large eddy simulation for a multi-car lift systems. A better understanding of piston effect in the context of lighter and faster multi-car systems is necessary to further calculate the impact of these forces on lighter structures. In this paper a coupled Fluid-Structure Interaction (FSI) model is developed based on stiffness and damping of the system and boundary values from transient CFD study. This study will help understand the impact of excitations due to aerodynamic forces and understand the effect of aerodynamic drags and piston forces in the multi-car shaft systems