473 research outputs found
Pension plans and the retirement replacement rates in the Netherlands
This study compares the expected retirement replacement rates of several cohorts of Dutch employees at the time of their planned retirement with the 'actual' replacement rates based on available pension records. We find that using reasonable indexation rates, the expected replacement rates�are higher than the one we compute. Larger discrepancies are found for younger cohorts. We decompose the difference between the expected and 'actual' replacement rates and find that the mismatch is related to poor institutional knowledge for the whole sample. We also show the role of assumptions on institutions and on wage profiles in determining our results.
The Mobile Spatial coordinate Measuring System II (MScMS-II):system description and preliminary assessmentof the measurement uncertainty
According to the increasing interest in metrological systems for the dimensional measurements
of large-size objects in a wide range of industrial sectors, several solutions based on different technologies,
working principles, architectures, and functionalities have recently been developed. Among all, the most
flexible and easily transportable solutions are those that have aroused most interest and have found greater
success. In order to address the needs of Large-Scale Metrology (LSM) applications, a distributed flexible
system based on a network of low-cost InfraRed (IR) sensors – the Mobile Spatial coordinate Measuring
System II (MScMS-II) – has been developed at the Industrial Quality and Metrology Laboratory of
Politecnico di Torino. This paper presents a preliminary uncertainty assessment of the system referring
to the measured point coordinates in the 3D space, focusing on the sources of measurement uncertainty
and the related propagation laws. A preliminary metrological characterization of MScMS-II architecture,
experimentally evaluated through a system prototype, is also presented and discussed
Flexible aggregation operators to support hierarchization of Engineering Characteristics in QFD
Quality Function Deployment (QFD) is a management tool for organizing and conducting design activities of new products and/or services together with their relevant production and/or supply processes, starting from the requirements directly expressed by the end-users. It is organized in a series of operative steps which drive from the collection of the customer needs to the definition of the technical characteristics of the production/supply processes. The first step entails the construction of the House of Quality (HoQ), a planning matrix translating the Customer Requirements (CRs) into measurable product/service technical characteristics (Engineering Characteristics – ECs). One of the main goals of this step is to transform CR importances into an EC prioritization. A robust evaluation method should consider the relationships between CRs and ECs while determining the importance levels of ECs in the HoQ. In traditional approaches, such as for example Independent Scoring Method, ordinal information is arbitrarily converted in cardinal information introducing a series of controversial assumptions. Actually, the current scientific literature presents a number of possible solutions to this problem, but the question of attributing scalar properties to information collected on ordinal scales is far from being settled. This paper proposes a method based on ME-MCDM techniques (Multi Expert / Multiple Criteria Decision Making), which is able to compute EC prioritization without operating an artificial numerical codification of the information contained in the HoQ. After a general description of the theoretical principles of the method, a series of application examples are presented and discussed
Electrospun silk fibroin fibers for storage and controlled release of human platelet lysate
Human platelet lysate (hPL) is a pool of growth factors and cytokines able to induce regeneration of different tissues. Despite its good potentiality as therapeutic tool for regenerative medicine applications, hPL has been only moderately exploited in this field. A more widespread adoption has been limited because of its rapid degradation at room temperature that decreases its functionality. Another limiting factor for its extensive use is the difficulty of handling the hPL gels. In this work, silk fibroin-based patches were developed to address several points: improving the handling of hPL, enabling their delivery in a controlled manner and facilitating their storage by creating a device ready to use with expanded shelf life. Patches of fibroin loaded with hPL were synthesized by electrospinning to take advantage of the fibrous morphology. The release kinetics of the material was characterized and tuned through the control of fibroin crystallinity. Cell viability assays, performed with primary human dermal fibroblasts, demonstrated that fibroin is able to preserve the hPL biological activity and prolong its shelf-life. The strategy of storing and preserving small active molecules within a naturally-derived, protein-based fibrous scaffold was successfully implemented, leading to the design of a biocompatible device, which can potentially simplify the storage and the application of the hPL on a human patient, undergoing medical procedures such as surgery and wound care. Statement of Significance: Human platelets lysate (hPL) is a mixture of growth factors and cytokines able to induce the regeneration of damaged tissues. This study aims at enclosing hPL in a silk fibroin electrospun matrix to expand its utilization. Silk fibroin showed the ability to preserve the hPL activity at temperature up to 60 \ub0C and the manipulation of fibroin's crystallinity provided a tool to modulate the hPL release kinetic. This entails the possibility to fabricate the hPL silk fibroin patches in advance and store them, resulting in an easy and fast accessibility and an expanded use of hPL for wound healing
New developments in high performance cylinder heads: application of LHIP and SPLIT cylinder head concept
Since specific power output of new engines is increasing, many engine components are facing new challenges. Among these, cylinder heads have to withstand tougher operating conditions in terms of temperatures and loads, which are approaching the limits of present aluminum alloys and of the manufacturing processes currently applied. The paper discusses two approaches to possibly extend the application of Aluminum alloy heads beyond their present limits: the first is the application of the Liquid Hot Isostatic Pressing (LHIP®) process aimed to improve the quality of the castings; the second is a novel design concept, split cylinder head, based on the application of different materials in different parts of the head, in order to achieve locally the required material properties
MScMS-II: an innovative IR-based indoor coordinate measuring system for large-scale metrology applications
According to the current great interest concerning large-scale metrology applications in many different fields of manufacturing industry, technologies and techniques for dimensional measurement have recently shown a substantial improvement. Ease-of-use, logistic and economic issues, as well as metrological performance are assuming a more and more important role among system requirements. This paper describes the architecture and the working principles of a novel infrared (IR) optical-based system, designed to perform low-cost and easy indoor coordinate measurements of large-size objects. The system consists of a distributed network-based layout, whose modularity allows fitting differently sized and shaped working volumes by adequately increasing the number of sensing units. Differently from existing spatially distributed metrological instruments, the remote sensor devices are intended to provide embedded data elaboration capabilities, in order to share the overall computational load. The overall system functionalities, including distributed layout configuration, network self-calibration, 3D point localization, and measurement data elaboration, are discussed. A preliminary metrological characterization of system performance, based on experimental testing, is also presente
A Modified Rabbit Ulna Defect Model for Evaluating Periosteal Substitutes in Bone Engineering: A Pilot Study
The present work defines a modified critical size rabbit ulna defect model for bone regeneration in which a non-resorbable barrier membrane was used to separate the radius from
the ulna to create a valid model for evaluation of tissue-engineered periosteal substitutes.
Eight rabbits divided into two groups were used. Critical defects (15 mm) were made
in the ulna completely eliminating periosteum. For group I, defects were filled with a
nanohydroxyapatite poly(ester urethane) scaffold soaked in PBS and left as such (group
Ia) or wrapped with a tissue-engineered periosteal substitute (group Ib). For group II, an
expanded-polytetrafluoroethylene (e-PTFE) (GORE-TEX\uae) membrane was inserted around
the radius then the defects received either scaffold alone (group IIa) or scaffold wrapped
with periosteal substitute (group IIb). Animals were euthanized after 12\u201316 weeks, and
bone regeneration was evaluated by radiography, computed microtomography (\ub5CT), and
histology. In the first group, we observed formation of radio-ulnar synostosis irrespective
of the treatment. This was completely eliminated upon placement of the e-PTFE (GORETEX\uae) membrane in the second group of animals. In conclusion, modification of the model
using a non-resorbable e-PTFE membrane to isolate the ulna from the radius was a valuable
addition allowing for objective evaluation of the tissue-engineered periosteal substitut
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Naming names: Perceptions of name-based HIV reporting, partner notification, and criminalization of non-disclosure among persons living with HIV
Policies of name-based HIV reporting, partner notification (PN), and criminalization of non-disclosure of HIV positive status to sexual partners remain controversial. The views of people living with HIV (PLH) are critical to the success of these three initiatives, but have been understudied. Thus, we interviewed 76 PLH about these policies. Themes arose of potential public health benefits (e.g., epidemiological surveillance and notification of possible exposure) and costs (e.g., deterrence of testing); threats to privacy, civil rights and relationships; government mistrust; and beliefs that prevention is an individual, not governmental responsibility. Misperceptions about the intent, content and scope of these policies, and past experiences of discrimination, shaped these attitudes. To enhance development and implementation of HIV prevention strategies, the views of PLH must be taken into account, and education campaigns need to address misperceptions and mistrust. These data shed light on difficulties in developing and implementing policies that may affect sexual behavior, and have critical implications for future research
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