Strength and deformation modification factors of wood based composites for engineering design

This paper summarizes some of the findings from a comprehensive study concerning the performance of wood based composites in building construction. The presentation only focuses on the strength and deformation modification factors for engineering design of wood based composites, that is, i) to determine whether the strength and deformation modification factors (kmod and kdef ) in Eurocode 5 for formaldehyde based boards are applicable to boards manufactured using new alternative binders such as isocyanate and cement, ii) to evaluate the effect of long-term concentrated loading by a full scale component test and small-scale indicative test, and iii) to examine the effect of long-term shear loading (panel and planar shears) on the performance of wood based composites for structural uses in comparison with long term bending loading in Eurocodes 1 and 5. Numerous results and important findings showed that i) the kc and kd values of isocyanate bonded particleboard (PB) under bending loads were lower than those of formaldehyde based PB, the former being 70-80% the latter; ii) the kc of cement bonded particleboard (CBPB) were similar to that of formaldehyde based particleboards, but with the deflection of the former being about 1/5 the latter, the CBPB test pieces lasted much longer than MUFPB under duration of load tests; iii) stress modes had a significant effect on long term performance: The extrapolated kc values under concentrated load were generally higher than those under bending load and in EC5, depending on the type of materials and joint profiles, the extrapolated kd were very similar between concentrated and bending loads and in EC5, the extrapolated kd values under shear load were higher than those in EC5, however, the kc values varied considerably with the type of oriented strand boards (OSB) and medium density boards (MDF) under shear loading tests. The results clearly showed that there is a need for developing strength and deformation modification factors for new materials and materials under various stress modes for engineering designs

Corporate branding in the retail sector: a practitioner’s perspective

It can be argued that corporate branding is essentially a strategic task spanning across functional boundaries and internal and external sphere of the organisation. What is the opinion of practitioners on the concept? This paper presents the findings from a study in the UK retail sector. The purpose of the study is to assess whether the practitioners share the view that the corporate brand is an integrative device and the process of corporate branding is holistic in nature

First-principles materials design of high-performing bulk photovoltaics with the LiNbO3_3 structure

The bulk photovoltaic effect is a long-known but poorly understood phenomenon. Recently, however, the multiferroic bismuth ferrite has been observed to produce strong photovoltaic response to visible light, suggesting that the effect has been underexploited as well. Here we present three polar oxides in the LiNbO$_3$ structure that we predict to have band gaps in the 1-2 eV range and very high bulk photovoltaic response: PbNiO$_3$, Mg$_{1/2}$Zn$_{1/2}$PbO$_3$, and LiBiO$_3$. All three have band gaps determined by cations with $d^{10}s^0$ electronic configurations, leading to conduction bands composed of cation $s$-orbitals and O $p$-orbitals. This both dramatically lowers the band gap and increases the bulk photovoltaic response by as much as an order of magnitude over previous materials, demonstrating the potential for high-performing bulk photovoltaics

Nonlinear analysis of phased-locked loops with rapidly varying phase

The performance of command and telemetry systems, useful in deep-space communications, is frequently affected by the radio-frequency phase error which is introduced at the point of reception by means of the carrier tracking loop. In low data rate communications, this phase error may vary rapidly over the duration of the signaling interval. In this paper such phase variation is characterized by a sinusoidal input phase, K sin (omega sub o t+, pi/6), which models a typical phase variation in communication over turbulent media. Conditions for synchronization stability and the acquisition behavior are examined by detailed computer study of the phase-plane trajectories for the second and third-order loops with perfect integrator. It is demonstrated that for the phase variation considered the third-order loop has no real advantage over the second-order loop. Finally, it is shown that nonzero initial conditions may result in large steady-state phase error

Towards Fully Additively-Manufactured Permanent Magnet Synchronous Machines: Opportunities and Challenges

With the growing interest in electrification and as hybrid and pure electric powertrains are adopted in more applications, electrical machine design is facing challenges in terms of meeting very demanding performance metrics for example high specific power, harsh environments, etc. This provides clear motivation to explore the impact of advanced materials and manufacturing on the performance of electrical machines. This paper provides an overview of additive manufacturing (AM) approaches that can be used for constructing permanent magnet (PM) machines, with a specific focus on additively-manufactured iron core, winding, insulation, PM as well as cooling systems. Since there has only been a few attempts so far to explore AM in electrical machines (especially when it comes to fully additively-manufactured machines), the benefits and challenges of AM have not been comprehensively understood. In this regard, this paper offers a detailed comparison of multiple multi-material AM methods, showing not only the possibility of fully additively-manufactured PM machines but also the potential significant improvements in their mechanical, electromagnetic and thermal properties. The paper will provide a comprehensive discussion of opportunities and challenges of AM in the context of electrical machines

A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey

We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The comparison between the N-rich quasars and other quasars shows that the two quasar subsets share many common properties. We also confirm previous results that N-rich quasars have much stronger Lya and NV lambda 1240 emission lines. Strong nitrogen emission in all ionization states indicates high overall nitrogen abundances in these objects. We find evidence that the nitrogen abundance is closely related to quasar radio properties. The radio-loud fraction in the NIII]-rich quasars is 26% and in the NIV]-rich quasars is 69%, significantly higher than ~8% measured in other quasars with similar redshift and luminosity. Therefore, the high nitrogen abundance in N-rich quasars could be an indicator of a special quasar evolution stage, in which the radio activity is also strong.Comment: 8 pages, 4 figures; accepted by ApJ (ApJ June 10, 2008, v680 n1 issue

Development of a super ductile diecast Al-Mg-Si alloy

This is the post-print version of the final paper published in Materials Science and Engineering A. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.The super ductile diecast aluminium alloys have been developed particularly for application in automotive body structure. On the basis of the reviewing aluminium alloys currently available, the requirement of diecast aluminium alloys is summarized and the Al-Mg-Si system is focused in the development. The effect of various alloying elements on the microstructure and the mechanical properties, such as yield strength, ultimate tensile strength and elongation is assessed. The optimized composition of the super ductile Al-Mg-Si alloy has been found to be at 5.0-5.5wt% Mg, 1.5-2.0wt% Si, 0.5-0.7wt% Mn, 0.15-0.2wt% Ti with Fe <0.25wt% for the best combination of strength and ductility, which shows 150MPa of yield strength, 300MPa of ultimate tensile strength, and 15% of elongation under as-cast condition. The paint baking hardenability of the optimized alloy is found to be insignificant. Less than a 10% increase in the yield strength was achieved, with a slight decrease in the elongation after aging at 180°C for 30min, which is a simulated process of paint baking. Cu is found to slightly increase the yield strength under the as-cast condition and after the heat treatment, but with a significant reduction in the ductility. Therefore, Cu should be limited in the super ductile aluminium alloy. The microstructure of diecast aluminium alloys at the optimized composition consists of the primary α-Al phase, the α-AlFeMnSi intermetallics and the Al-Mg Si eutectics. There are two types of primary α-Al phase: dendritic or fragmented dendritic α-Al phase solidified in the shot sleeve and globular α-Al particles solidified in the die cavity. The α-AlFeMnSi intermetallics is in the form of compact morphology and with a size of less than 3μm. The eutectic cells are at size of 10μm with a typical lamellar morphology of α-Al phase and Mg Si phase.EPSRC and JLRUK