Design and evaluation of an active electromechanical wheel suspension system

This paper presents an electromechanical wheel suspension, where the upper arm of the suspension has been provided with an electric levelling and a damper actuator, both are allowed to work in a fully active mode. A control structure for the proposed suspension is described. The complex design task involving the control of the electric damper and its machine parameters is tackled by genetic optimisation. During this process, these parameters are optimised to keep the power dissipation of the electric damper as low as possible, while maintaining acceptable comfort and road-holding capabilities. The results of the evaluations carried out demonstrate that the proposed suspension can easily adopt its control parameters to obtain a better compromise of performance than that offered by passive suspensions. If the vehicle is to maintain acceptable performance during severe driving conditions, the damper has to be unrealistically large. However, if the electric damper is combined with a hydraulic damper, the size of the electric damper is significantly reduced. In addition, the design of the electric damper with the suggested control structure, including how it regenerates energy, is discussed.     

Reproducing ten years of road ageing — Accelerated carbonation and leaching of EAF steel slag

Reuse of industrial aggregates is still hindered by concern for their long-term properties. This paper proposes a laboratory method for accelerated ageing of steel slag, to predict environmental and technical properties, starting from fresh slag. Ageing processes in a 10-year old asphalt road with steel slag of electric arc furnace (EAF) type in the subbase were identified by scanning electron microscopy (SEM) and leaching tests. Samples from the road centre and the pavement edge were compared with each other and with samples of fresh slag. It was found that slag from the pavement edge showed traces of carbonation and leaching processes, whereas the road centre material was nearly identical to fresh slag, in spite of an accessible particle structure. Batches of moisturized road centre material exposed to oxygen, nitrogen or carbon dioxide (CO₂) were used for accelerated ageing. Time (7-14 days), temperature (20-40 °C) and initial slag moisture content (8-20%) were varied to achieve the carbonation (decrease in pH) and leaching that was observed in the pavement edge material. After ageing, water was added to assess leaching of metals and macroelements. 12% moisture, CO₂ and seven days at 40 °C gave the lowest pH value. This also reproduced the observed ageing effect for Ca, Cu, Ba, Fe, Mn, Pb, Ca (decreased leaching) and for V, Si, and Al (increased leaching). However, ageing effects on SO₄, DOC and Cr were not reproduced.     

Hardware variability in the three-dimensional measurement of autobody steel panel surfaces

Automotive panel manufacture is an important industrial activity. Research in this area has recently been assisted by an European Community funded research programme on three-dimensional characterisation of steel sheet. This paper describes the results of the first part of the programme in which the emphasis is on a Round Robin Test of the partners measuring equipment. Software was identified as being one of the major causes of variability. It is concluded that standard and stable algorithms are a necessity to ensure reliable interchange of data.     

Residual animal fat and fish for biodiesel production. Potentials in Norway

The potential for biodiesel production based on utilization of residual animal fat and fish in Norway is estimated. This is based on a study of the amounts of residual fat that is possible to recover from grease traps in Bergen. Additional data from Trondheim and Oslo facilitated up-scaling to estimating national potential for utilizing this residue stream for biodiesel production. This is supplemented with data on residues from slaughterhouses and poultry, as well as the fishing industry. The results indicate that Norway has the potential for producing large amounts of biodiesel from these residue sources.     

Accurate large-signal GaAs MESFET and HEMT modeling for power MMIC amplifier design

This article describes, from an industrial user's point of view, how large-signal GaAs MESFET and HEMT modeling can be done accurately and efficiently for power MMIC amplifier design. The method is based on commercially available CAD tools enhanced by in-house software (e.g., small-signal parameter extraction, generation of load-pull contours). The Materka model is shown to predict accurately the large-signal characteristics of GaAs MESFETs, but not of pseudomorphic HEMTs. For these devices, a modified Angelov model is found to be adequate. A method for determining the numerous large-signal model parameters is presented. Model verification is achieved by comparing simulated and on-wafer measured data like static I(V)-characteristics, multiple bias S-parameters, gain compression characteristics, and load-pull contours. Results of device scaling and calculations of optimum load impedances are discussed. The close fit to the measured data proves that an excellent basis for large-signal power MMIC design has been established.     

Preclinical Evaluation of 99mTc-ZHER2:41071, a Second-Generation Affibody-Based HER2-Visualizing Imaging Probe with a Low Renal Uptake

Radionuclide imaging of HER2 expression in tumours may enable stratification of patients with breast, ovarian, and gastroesophageal cancers for HER2-targeting therapies. A first-generation HER2-binding affibody molecule [^99mTc]Tc-ZHER2:V2 demonstrated favorable imaging properties in preclinical studies. Thereafter, the affibody scaffold has been extensively modified, which increased its melting point, improved storage stability, and increased hydrophilicity of the surface. In this study, a second-generation affibody molecule (designated ZHER2:41071) with a new improved scaffold has been prepared and characterized. HER2-binding, biodistribution, and tumour-targeting properties of [^99mTc]Tc-labelled ZHER2:41071 were investigated. These properties were compared with properties of the first-generation affibody molecules, [^99mTc]Tc-ZHER2:V2 and [^99mTc]Tc-ZHER2:2395. [^99mTc]Tc-ZHER2:41071 bound specifically to HER2 expressing cells with an affinity of 58 ± 2 pM. The renal uptake for [^99mTc]Tc-ZHER2:41071 and [^99mTc]Tc-ZHER2:V2 was 25–30 fold lower when compared with [^99mTc]Tc-ZHER2:2395. The uptake in tumour and kidney for [^99mTc]Tc-ZHER2:41071 and [^99mTc]Tc-ZHER2:V2 in SKOV-3 xenografts was similar. In conclusion, an extensive re-engineering of the scaffold did not compromise imaging properties of the affibody molecule labelled with ^99mTc using a GGGC chelator. The new probe, [^99mTc]Tc-ZHER2:41071 provided the best tumour-to-blood ratio compared to HER2-imaging probes for single photon emission computed tomography (SPECT) described in the literature so far. [^99mTc]Tc-ZHER2:41071 is a promising candidate for further clinical translation studies.     

Topology optimization of periodic 3D heat transfer problems with 2D design

Structural and Multidisciplinary Optimization - We consider a model for density-based topology optimization (TO) of stationary heat transfer problems with design-dependent internal convection in 3D...     

Influence of spacer groups on grafting ability,curing ability,and film properties of water-based radiation curable latexes

Film-forming polystyrene/poly(n-butyl acrylate-co-glycidyl methacrylate) [PS/P(BA-co-GMA)] core–shell latex particles were prepared via a two-stage emulsion polymerization procedure using a PS latex seed. A delayed addition of GMA was used to locate the functional epoxy groups near the surface of the particles. The surface-bound epoxy groups were used as grafting sites for unsaturated carboxyl functional monomers having the unsaturated groups and the carboxylic group separated by 1, 5, or 10 oxyethylene units. Grafting and curing characteristics and film properties after irradiation were investigated as a function of the number of oxyethylene units. A BA-GMA [P(BA-co-GMA)] copolymer was used as a model system for the core–shell latex particles for quantification of the grafting reactions. The grafting was demonstrated by FTIR and ¹H-NMR spectroscopy. The effects of crosslinking was studied by thermal mechanical analysis and dynamical mechanical analysis. Differential photocalorimetry was also used for evaluation of the curing ability. It was demonstrated that the reagent having five oxyethylene units in the spacer group was grafted onto the polymer backbones to a larger extent than the other two reagents, and a more thoroughly cured film was obtained upon irradiation. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 897–906, 1998     

Comparable Characterization of Nanocellulose Extracted from Bleached Softwood and Hardwood Pulps

In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared analysis (FT-IR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The experimental results showed that the nanocellulose products derived from spruce pulp exhibited a relatively larger particle size, higher crystallinity, and higher thermal stability, compared with the corresponding products obtained from aspen pulp under the same conditions. Furthermore, the study helped establish that the properties of the nanocellulose products were highly dependent on the nature of the starting materials under identical processing conditions.     

Estimation of the risk for early thermal cracking for SCC containing fly ash

Cracking of concrete must be avoided during the hardening phase in order to minimize the risk of durability problems in the future, such as corrosion of the reinforcement, water tightness and damages due to frost. Estimation of the risk of early age cracking requires knowledge of the combined effects from temperature development and mechanical behaviour during the hydration. In the present paper, the influence of fly ash on the young concrete behaviour has been investigated. The concrete is based on a Swedish cement aimed for civil engineering structures, and the fly ash is of class F. A comparison of crack risks between concrete containing fly ash in different amounts with concrete without fly ash is presented. Also a previously tested concrete containing limestone filler is considered. The fly ash was added to replace a part of the aggregate, which gives a higher heat evolution. However, a numerical stress analysis showed that the risk for early age through cracking for a typical civil engineering structure is significantly decreased in the mixes containing fly ash. The denotation typical civil engineering structure is used here for concrete structures such as tunnels, bridges, and ramps of common cross-section dimensions. In the case of fly ash added to concrete by a partial replacement of cement, the crack risk will probably be further decreased. For a self-balancing structure of young concrete there is no restraint from adjacent structures, and the temperature and moisture gradients within the young concrete cause self-stresses governed by equilibrium with zero external forces for any cut. The estimated risk for surface cracking on a self-balancing wall or slab was not improved by an addition of fly ash. It is probably an effect of the increased heat development, which most likely counteracts the positive effect of the increased early age creep for concrete containing fly ash. If the heat evolution decreases when cement is partly replaced with fly ash, the use of fly ash might reduce the risk of surface cracks.