Untersuchungen zum Ermüdungsverhalten von Konstruktionsteilen für Mobilkrane

Fatigue behaviour of component sections of mobile cranes out of high strength steel plates. High‐strength structural steels with 960 and/or 1100 MPa minimum yield strength allow a decrease of the investment and operating costs of mobile cranes through lightweight design. However, there still exists an uncertainity for stress resistance under cyclic loads and bearable stresses concerning fatigue behaviour of important crane components. This paper deals for the first time with the fatigue behaviour of crane components examined under realistic load‐time‐cycles derived from realistic crane operating conditions. The results supply important information on the service life. The service life depends in this case strongly from the tension level considerably. The influence of the here applied load‐time‐cycles appears on the other hand small. Additionally, this paper provides a new tool with which the fatigue behaviour of crane components under most different aspects and involved variable combinations can be estimated, consistent with measured values, through a fracture mechanically based model. There can be made important procedure recommendations and hints can be given for a more intense use of high‐strength structural steels for practical application in mobile crane engineering. Inspection intervals and contents can be newly determined. The usage of steels with more than 1100 MPa minimum yield strength in the mobile crane building is evaluated crucially.     

Testing the credit view with pooled data: dynamic links among state bank health, investment-oriented bank loans, and economic performance

This paper focuses on the “credit view” theory at the state level, which suggests that state-level banking sector health influences state-level real economic performance. Specifically, we extend typical analysis of the credit view theory, applying relevant state-level economic variables to consider whether the health of a state’s banking system affects capital investment loans and, in turn, whether growth of these loans affects a state’s economic performance. We develop a two-equation state-level model, use more refined measures of capital investment loans, and apply advanced dynamic pooled estimators to our panel of state data for the 1984–1993 period. Regression results support dynamic links among state bank health, state investment-oriented bank loans, and state economic performance, thus supporting existence of a state-level credit channel effect.

Herstellung,Verarbeitung und Eigenschaften höherfester Stähle für den Einsatz in Windenergieanlagen

Production, processing and properties of higher‐strength steel plates for application in wind energy plants. The mechanical and technological demands on steels for offshore wind energy plants are high. Advanced technologies in steel production make normalized or thermomechanically rolled plates with minimum yield strengths up to 460 MPa as well as quenched and tempered steels with minimum yield strengths from 520 up to 1100 MPa available for construction. Plates with up to 460 MPa are well established for building wind energy plants. Material properties and processing of these steel grades are well known. High‐strength steels offer further possibilities for construction. These steels are characterised by high yield strength and at the same time high toughness and excellent processing behaviour. By modern fracture mechanical safety concepts, it could be shown, that even under critical service conditions there can be guaranteed a high level of safety against brittle failure.     

Self-service reservation in the fieldforce

On-line service reservation is becoming increasingly popular in the service industry. As services become more complex, requiring co-ordination among individual actions, the planning for making service appointments is normally conducted manually by the operators, often resulting in slow responses to customers. To tackle this problem, we have developed a real-time service reservation portal that takes an order from a user and works out appointment options, based on the availability of enterprise resources, for the user to book on-line. The portal is capable of dealing with complex workflow appointing, supporting interactive fine-tuning in individual appointments, respecting customer preferences and work policies, monitoring progress of workflow, informing the customer of status changes in job scheduling, dispatching and execution, as well as handling exceptions automatically. We have integrated the portal, code-named FieldReserve, with other components in the BT fieldforce optimisation suite (FOS) that covers functions of resource planning, scheduling and execution for the fieldforce to demonstrate the feasibility and potential benefits of this technology. Benefits demonstrated are to provide customers with instant response of service reservation, to provide volume control on reservation, to break away from one-size-fits-all lead times for service fulfilment, to provide customers with equal access to service provision, and to bring transparency of service progress to customers. Currently, we are actively engaging with businesses and have obtained strong support to downstream the key values of this technology in commercial contexts.     

Manufacturing of electrical discharge machinable ZTA-TiC - hot pressing vs. spark plasma sintering

Hot pressing and spark plasma sintering were applied to manufacture electrical discharge machinable ZTA-TiC ceramics containing 17?vol.% zirconia (1.5Y) and 24?vol.% titanium carbide in an alumina matrix. Sintering was carried out at 1450–1600?°C and 40?MPa pressure with 2?h dwell for HP and 10?min for SPS. The influence of sintering conditions on mechanical properties, microstructure, phase composition and electrical conductivity was investigated. Both sintering technologies lead to fully densified samples with similar strength and toughness. Hardness was generally lower for SPS. SPS samples develop a finer microstructure. HP samples the TiC grains tend to merge at high sintering so that HP materials reach significantly higher conductivities. Productivity and energy consumption per piece can be significantly decreased by shifting to SPS. Both types of material were ED-machinable. Hot pressed ceramics showed better cutting performance and improved surface quality in trimming operations.     

Intestinal cytomegalovirus disease in immunocompromised patients may be ruled out by search for cytomegalovirus DNA in stool samples

Cytomegalovirus (CMV) PCR from stool specimens was adopted as a diagnostic tool for patients with suspected CMV colitis. After being established, the method was evaluated in 17 AIDS patients and 19 other immunocompromised patients by comparison of PCR results with clinical, histological, and microbiological or virological data. CMV PCR was positive in 4 symptomatic patients with proven CMV colitis and negative in 15 of 16 patients without characteristic histopathology. Neither CMV immunoglobulin G seropositivity nor intestinal symptoms alone were significantly associated with positive PCR results, but severe active systemic CMV infection may lead to a positive PCR. Absence of CMV DNA in stool samples may prove useful in ruling out CMV related colitis.     

Cloud effects on distributed photovoltaic generation: slowtransients at the Gardner, Massachusetts photovoltaic experiment

The Photovoltaic Generation Effects project was undertaken to verify that no serious consequences arise from the interconnection of distributed photovoltaic generation on electric power distribution systems. Here, slow transient responses at frequencies corresponding to fluctuations of photovoltaic generation resulting from the passage of clouds over the experiment site in Gardner, Massachusetts, are described. A statistical basis is developed extending the measured results to the entire area served by the distribution circuit in Gardner, as it might be both loaded and equipped with photovoltaic generation in the twenty-first century. Observations and analyses of the solar irradiance and photovoltaic system performance at a single point indicate that there are insufficient step changes in load levels to cause voltage flicker problems. Numerical techniques developed for interpolation of irradiance conditions over the experiment site are adequate for estimating the irradiance at intermediate points and times. The technique appears to be adaptable to extrapolation over larger areas     

Evidence for effects of insulin on sensory processing in humans

Lessons learned from environmental and occupational hazard risk management practices over the past 30 years have led the Department of Defense to explore alternative risk management approaches. Policies for cleanup of environmentally hazardous waste sites are undergoing examination and are being reframed. A Demonstration Risk Communication Program is described which incorporates principles that integrate risk-based scientific information as well as community values, perceptions, and needs in a democratic process that includes the public as an active participant from the earliest stages. A strong scientific foundation for assessment and characterization of risk is viewed as necessary but not sufficient; the public's values must be actively integrated into the negotiated criteria. The Demonstration Program uses a model to prepare the participants and to guide them through the process. A five-step process is presented: (1) create risk communications process action team including at least one member of the specific site audience; (2) professionally train participants on team dynamics including interpersonal communication skills; (3) train risk communicators to deliver a cogent presentation of the message to secure a decision acceptable to both the government and the public; (4) identify existing biases, perceptions, and values held by all participants; and (5) develop risk message incorporating science and values. The process action team approach assumes the participants enter into the effort with the goal of improved environment and safeguarded public health. The team approach avoids confrontational or adversarial interactions and focuses on a dialogue from which a negotiated team response develops. Central to the program is the recognition that communication is only effective when the dialogue is two-way.     

Dielectric analysis of epoxy/amine resins using microwave cavity technique

Dielectric properties (permittivity and dielectric loss factor) of stoichiometric mixtures of DGEBA (diglycidylether of bisphenol A) epoxy (DER 332) and amine (diaminodiphenyl sulfone; DDS) as a function of temperature and extent of cure have been measured at a microwave frequency of 2.45 GHz. Permittivity and dielectric loss factor of this resin increase with increasing temperature and decrease with increasing extent of cure. Dielectric loss factor is more dependent on temperature in the early stages of cure but becomes less dependent on temperature as the cure proceeds. Dielectric loss data can be related to extent of cure in order to monitor the cure process. Online measurements of temperature- and cure-dependent dielectric loss factor show three material structure stages and significant changes in dielectric loss factor during the microwave cure process. Dielectric Joss factor is also found to be the same for both thermal and microwave cured samples.