Suspension system performance optimization with discrete design variables

Suspension systems on commercial vehicles have become an important feature meeting the requirements from costumers and legislation. The performance of the suspension system is often limited by available catalogue components. Additionally the suspension performance is restricted by the travel speed which highly influences the ride comfort. In this article a suspension system for an articulated dump truck is optimized in sense of reducing elapsed time for two specified duty cycles without violating a certain comfort threshold level. The comfort threshold level is here defined as a whole-body vibration level calculated by ISO 2631-1. A three-dimensional multibody dynamics simulation model is applied to evaluate the suspension performance. A non-gradient optimization routine is used to find the best possible combination of continuous and discrete design variables including the optimum operational speed without violating a set of side constraints. The result shows that the comfort level converges to the comfort threshold level. Thus it is shown that the operational speed and hence the operator input influences the ride comfort level. Three catalogue components are identified by the optimization routine together with a set of continuous design variables and two operational speeds one for each load case. Thus the work demonstrates handling of human factors in optimization of a mechanical system with discrete and continuous design variables.     

Transmission properties for individual electrochromic layers in solid state devices based on polyaniline, Prussian Blue and tungsten oxide

In order to investigate the transmission properties in the whole solar spectrum for individual electrochromic layers in solid state devices incorporating polyaniline (PANI), Prussian Blue (PB) and tungsten oxide (WO3), the devices were fabricated with and without holes in the electrochromic coatings in several combinations. Both PANI and WO3 were deposited electrochemically on indium–tin oxide (ITO) glass substrates, while PB was deposited on top of the PANI coatings or directly on the ITO glass plates. Solid state devices were made by gluing the glass plates together with the solid polymer electrolyte poly(2-acrylamido-2-methyl-propane-sulphonic acid) (PAMPS), and thus, with and without holes in the three electrochromic coatings in different combinations, enabling us to study the optical properties of PANI, PB and WO3 separately, that is, the hole method. This method gives good qualitative, and to a certain degree quantitative, information, which may be of valuable help in designing electrochromic devices with specific tailor-made optical properties.     

Estimation of forming limit diagrams by the use of the finite element method and Monte Carlo simulation

A stochastic finite element-based approach for forming limit calculations of sheets is proposed and evaluated. Material inhomogeneities are represented by spatial thickness variations of the sheet which are modelled by the use of random fields. The effects of changing the smoothness, wavelengths, amplitude and anisotropy of the field realisations on the forming limit diagram are investigated. Further, the effects of the patch size and plastic anisotropy on the forming limit diagram are studied. The assumed thickness variations result in a quite wide scatter band, and changes of the characteristics of the thickness field result in changes of the shape and variance of the forming limit diagram.     

Synthesis and structural studies of “branched” 2-linked trisaccharides related to h-type 2 blood group determinants

A series of fucosylated trisaccharides l-Fuc-(1→2)-ß-d-Gal-(1→4)-ß-X-OMe (1-6, X = d-GlcNAc, d-Qui (6-deoxy-Glc), d-Xyl) related to H type 2 blood group determinant have been synthesized both as their α- and ß- L-Fuc anomers together with the component disaccharide starting compounds (7-11). The conformational properties of the trisaccharides together with their parent disaccharides have been investigated by NMR spectroscopy (proton and carbon chemical shifts and proton NOEs) in combination with computer modeling using the Monte Carlo approach and the HSEA force field using the GEGOP program with the main focus on the α-linked fucose series. The series of compounds allow for the investigation of interaction between the sugar units in the—in principle—linear structures, which in practice behave as branched trisaccharides. The interaction between the terminal fucose unit and the unit at the reducing end has been probed by substitution of the bulky CH₂OH group with CH₃ and H substituents, respectively. Compounds with severe steric interactions can be identified by the non-additivity of their carbon chemical shifts and subsequently confirmed by the detailed conformational assessment by NOEs and computer modeling. The most severe contacts arise in the GlcNAc and Qui trisaccharide series, whereas the Xyl-containing trisaccharide derivatives only exhibit weak steric interaction as probed by the NMR parameters.     

Identification of Novel Fragments Binding to the PDZ1-2 Domain of PSD-95

Inhibition of PSD-95 has emerged as a promising strategy for the treatment of ischemic stroke, as shown with peptide-based compounds that target the PDZ domains of PSD-95. In contrast, developing potent and drug-like small molecules against the PSD-95 PDZ domains has so far been unsuccessful. Here, we explore the druggability of the PSD-95 PDZ1-2 domain and use fragment screening to investigate if this protein is prone to binding small molecules. We screened 2500 fragments by fluorescence polarization (FP) and validated the hits by surface plasmon resonance (SPR), including an inhibition counter-test, and found four promising fragments. Three ligand efficient fragments were shown by ¹H,¹⁵N HSQC NMR to bind in the small hydrophobic P⁰ pockets of PDZ1-2, and one of them underwent structure-activity relationship (SAR) studies. Overall, we demonstrate that fragment screening can successfully be applied to PDZ1-2 of PSD-95 and disclose novel fragments that can serve as starting points for optimization towards small-molecule PDZ domain inhibitors.     

Effects of particle characteristics on bulk properties of norwegiata fish meals

Three categories of Norwegian fish meats with different particle size, shape and particle surface stickiness characteristics were exposed to angle of repose and bulk density tests. The results presented indicate that the angle of repose increases with decreasing particle size, increasing amounts of fibrous particles in the powder and increasing particle surface stickiness. The bulk density, on the other hand, did not correlate with the particle size in the range considered, but increased with decreasing amounts of fibrous materials and decreasing surface stickiness.     

Experimental determination of mushy zone permeability in aluminum-copper alloys with equiaxed microstructures

An experimental apparatus for measuring the mushy zone permeability of aluminum-copper alloys with equiaxed microstructures has been constructed. Permeabilities have been measured for high solid fractions (0.68 to 0.91) and different dendrite morphologies. Microstructure characterizations on both the interdendritic and extradendritic length scales have been performed on the samples. The results are in fairly good agreement with the predictions of the Kozeny-Carman relation and with more recent theory that takes flow partitioning between interdendritic and extradendritic regions into account.     

Optimisation of the broiler production supply chain

In this paper, we propose a mixed integer programming (MIP) model for the Chicken Flock Sizing, Allocation and Scheduling Problem (CFSASP), which is an important planning problem in the broiler production supply chain. To solve the CFSASP efficiently, two variants of rolling horizon heuristics (RHHs) have been developed and applied on the case of a Norwegian broiler production company. Computational results show that the RHHs successfully obtain high-quality solutions within a reasonable time. The value of optimisation is verified through comparison with the case company's plans, where the solutions from optimisation outperforms the current solutions. Sensitivity analyses are also conducted to provide managerial insights regarding certain strategic decisions, such as how many and which days to use for hatching of chickens. Due to the promising results, the case company is now implementing an optimisation-based decision support system based on the MIP model and solution methods shown in this paper.     

Effect of humidity and chloride content on the corrosion of steel embedded in LWA concrete

Measurements have been made with mortar specimens with light aggregates (LWA) and the cements Norcem HS65 and MP30, corresponding to CEM I and CEM II. The w/b ratio was 0.30 and 0.40 and in one mix prewetted LWA was used. The silica fume addition was 8%. The specimens have two sets of electrodes consisting of a 10 mm reinforcing steel and a 10 mm rod of stainless steel. In the start of the experiment the chloride penetration was accelerated by applying a voltage between a negatively charged steel plate within the salt solution and a positively charged net of stainless steel embedded in the concrete above the reinforcing steels. This caused some problems and the set-up was changed to using a Plexiglas brim and a solution of calcium hydroxide and sodium chloride was applied. In the solution, a titanium net was placed and a positive voltage of 12 V was applied between the embedded steels and the net with the titanium net as the positive pole. Measuring galvanic currents, electrochemical potential and polarisation resistances have presented a good picture of the corrosion activity of the embedded steels. There is a distinct effect of the humidity upon the corrosion activity registered by the electrochemical measurements. There is a good relation between the electrochemical measurements and the observed corrosion attacks at the end of the experiments. The LWA concrete with water saturated aggregates showed more corrosion than the corresponding LWA concrete with dry aggregates. The rates of corrosion measured both as a galvanic current and as a function of the polarisation resistance showed that the concrete with watered aggregate concrete had a corrosion rate about twice as high as the corresponding LWA concrete with dry aggregates. There are marked differences in the chloride penetration for the different cements. Effects have been observed on the chloride content of the different concretes. Lower w/b ratio, MP30 cement compared to HS65 and no prewatering of the LWA gave less chloride penetration.