Design issues of BAW employment in 3D integrated sensor nodes

In the field of wireless sensor node design a wide range of new potentials are opened by means of emerging 3D integration technologies. These technologies enable the design of highly integrated sensor nodes, but the designers face novel challenges, which specialized communications engineers are not familiar with. This work presents an advanced direct tire pressure monitoring system (TPMS) with an overall size below 1 cm³ applying through silicon vias (TSV) and points out two selected design issues arising due to this high level of integration. At first design issues caused by temperature gradients within the 3D integrated chip stack are presented. Multi physics simulations show that a systematical temperature measurement error is introduced by self heating, which would affect the communication performance if unconsidered. Furthermore the radio frequency (RF) characteristics of TSVs, focusing on their electrical efficiency, are investigated. In particular the behavior of TSVs for connecting a bulk acoustic wave resonator with an impedance of 2 kΩ at 2.1 GHz is evaluated in detail.     

The construction of research questions in project management

This article examines how opportunities for contributions are created in project research. In the article the arguments that underlie research question constructions are analyzed and their role in theory construction is reflected upon. The analysis is based upon a review of 61 papers published between 2007 and 2011 in the four major project management outlets. The results show that questions identify gaps and extend literature rather than challenge the theoretical assumptions. It is argued that the dominance of “gap spotting” hampers the development of the project field by producing theories that do not challenge long-held, sometimes possibly false, assumptions. Researchers are therefore urged to become bolder in their claims, some suggestions on how to achieve this are offered.     

Spatio-Temporal Data Types: An Approach to Modeling and Querying Moving Objects in Databases

Spatio-temporal databases deal with geometries changing over time. In general, geometries cannot only change in discrete steps, but continuously, and we are talking about moving objects. If only the position in space of an object is relevant, then moving point is a basic abstraction; if also the extent is of interest, then the moving region abstraction captures moving as well as growing or shrinking regions. We propose a new line of research where moving points and moving regions are viewed as 3-D (2-D space+time) or higher-dimensional entities whose structure and behavior is captured by modeling them as abstract data types. Such types can be integrated as base (attribute) data types into relational, object-oriented, or other DBMS data models; they can be implemented as data blades, cartridges, etc. for extensible DBMSs. We expect these spatio-temporal data types to play a similarly fundamental role for spatio-temporal databases as spatial data types have played for spatial databases. The paper explains the approach and discusses several fundamental issues and questions related to it that need to be clarified before delving into specific designs of spatio- temporal algebras.     

Co‐operative Formation of Monolithic Tungsten Oxide–Polybenzylene Hybrids via Polymerization of Benzyl Alcohol and Study of the Catalytic Activity of the Tungsten Oxide Nanoparticles

Hard and brittle monolithic tungsten oxide‐polybenzylene nanohybrids can be obtained in one step by reacting tungsten iso‐propoxide with benzyl alcohol. In a first step, crystalline tungsten oxide W₁₈O₄₉ nanowires with a diameter of about 1.5 nm form via ether elimination reaction. Subsequently, the large residue of the benzyl alcohol is transformed to dibenzyl ether, which then polymerizes to polybenzylene, incorporating the nanoparticles into the forming polymer. The catalytic effect of the tungsten oxide nanowires on the quantitative formation of polybenzylene is proven by reacting them in different concentrations and at varying temperatures either with benzyl alcohol or with dibenzyl ether. Complete polymerization of benzyl alcohol is achieved within just 30 min by using a particle‐to‐monomer molar ratio of 1:115 at 160 °C. Lower reaction temperatures (100–130 °C) or higher ratios (1:340 and 1:680) prolong the reaction time to several hours. Further studies show that the tungsten oxide nanoparticles are able to completely polymerize various other alcohols with an aryl methanol group.     

Dynamic modelling of E-waste recycling system performance based on product design

E-waste covers a wide range of products as well as dismantled and/or sorted components originating from these. Being able to predict the flow of materials and recycling performance for different E-waste types requires a fundamental and flexible basis in which E-waste design properties are linked to liberation and separation performance of recycling. This paper discusses the authors’ design-determined liberation and dynamic models to predict and monitor E-waste recycling technologically, economically and environmentally.The uniqueness of this work lies in the modelling of product design characteristics in terms of design tables that define the mass and material connections derived from the design in real-time. The shredding process is modelled by defining shredder connection, and shredder liberation tables, based on heuristic derived from extensive data collection on design and shredder experiments. This allows for the design-driven modelling of material liberation in the shredding process. The heuristic modelling of liberation behaviour and the prediction of particle composition and degree of liberation after shredding based on design-driven shredder modelling are a novel approach to link design to recyclate quality and recycling performance. Key to this work is that the multi- and mono-material composition of particles after liberation are not pre-defined as in earlier work, but are predicted as a function of design choices and can vary accordingly. The evolution of these models is underpinned by extensive industrial data collection on product design of various WEEE categories, which was used to define and calibrate the models.The time dependent characteristic of design and recycling technology requires the adoption of dynamic modelling to predict recycling performance over time. The discussed dynamic and predictive framework provides a first principles basis for the calculation of the dispersion of harmful/valuable elements and environmental impact. This optimizes the spending of money on large scale trials and monitoring test to establish these results. At the same time legislation and policy on recyclability of products can be tested if it stands the test of time or if new designs comply with environmental legislation in the future.Prediction of recycling performance, recyclate quality and toxicity as a function of product design, shredding and (future) recycling system configurations will be demonstrated in various industrial examples, which includes an evaluation if shredding is advisable or not for precious and platinum group elements recovery during recycling. Also the so important balance between energy recovery and feedstock recycling is shown.     

Migrating Autonomous Objects in a WAN Environment

Along with the fast progress the interconnection of computer systems makes the need for enterprise-wide distributed solutions grows. These systems have to support hundreds or even thousands of sites located all over the world. The distances between the sites will impose high communication costs on distributed activities thus significantly increasing their response times. This problem can be alleviated through migrating objects to the sites where they are needed. However, migration in such systems cannot be managed globally. Therefore, we present a migration protocol for (autonomous) objects which enables them autonomously to decide whether or not and which site to migrate to, thus making the system self-tuning. We also present two migration strategies objects can use to derive their migration decisions. The first one finds the optimal placement for an object while the second strategy in some cases returns a sub-optimal location but induces lower computation costs. The two strategies are evaluated through benchmarks in a distributed system of autonomous objects. The experiments show a significant decrease in communication costs when migration is employed.     

Influence of radiation cross‐linking of polyamide 66 on the characteristics of the vibration welding process

The conventional vibration welding process of polyamide 66 only has a continuous and steady melt flow during the quasi‐steady phase. The process and resulting welds have been thoroughly investigated. Radiation cross‐linking of polyamide 66 with electron beams alters the material's characteristics. Consequently, the resulting energy balance during vibration welding changes and the squeeze flow is impeded. Additionally, this causes the cross‐linking to attain a residual stiffness above the crystallite melting temperature, thereby influencing the characteristics of the vibration welding process. Further, higher weld temperatures and a change in meltdown behavior can be observed. This leads to a varied relationship amongst the process, structure, and properties for vibration welding cross‐linked polyamide. Hence, weld strengths up to the value of the base material strength are possible. The scope of this article is to investigate the influence of radiation cross‐linking on the material characteristics and, by extension, the resulting processing and welding characteristics. Calorimetric, chemical, rheological, mechanical, and optical investigations serve to highlight the influence of radiation cross‐linking on the vibration welding process of polyamide 66. POLYM. ENG. SCI., 55:2493–2499, 2015. © 2015 Society of Plastics Engineers