Adsorption of surfactant by hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate)] hydrogels and effect of surfactant adsorption on the volume phase transition

Hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate) [P(DEAEMA‐co‐NVP/OA)] hydrogels were synthesized by free‐radical crosslinking copolymerization of 2‐(diethylamino)ethylmethacrylate (DEAEMA), N‐vinyl‐2‐pyrrolidone (NVP) with different amounts of hydrophobic comonomer octadecyl acrylate (OA) in tert‐butanol with ethylene glycole dimethacrylate (EGDMA) as a crosslinker. The swelling equilibrium of the hydrogels was investigated as a function of temperature and hydrophobic comonomer content in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). The results indicated that the swelling behavior and temperature sensitivity of the hydrogels were affected by the type and concentration of surfactant solutions. Additionally, the amount of the adsorbed SDS and DTAB molecules onto the hydrogels was determined by fluorescence measurements. An increase of OA content in the hydrogel caused an increase in the amount of adsorbed surfactant molecules in both media. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3771–3775, 2007     

Adsorption of IgG on spacer‐arm and L‐arginine ligand attached poly(GMA/MMA/EGDMA) beads

This work presents data on human immunoglobulin G (HIgG) adsorption onto L ‐arginine ligand attached poly(GMA/MMA/EGDMA)‐based affinity beads which were synthesized from methyl methacrylate (MMA) and glycidiyl methacrylate (GMA) in the presence of a crosslinker (i.e., ethylene glycol dimethacrylate; EGDMA) by suspension polymerization. The epoxy groups of the poly(GMA/MMA/EGDMA) beads were converted into amino groups after reaction with ammonia or 1,6‐diaminohexane (i.e., spacer‐arm). With L ‐arginine as a ligand, it was covalently immobilized on the aminated (poly(GMA/MMA/EGDMA)‐ AA) and/or the spacer‐arm attached (poly(GMA/MMA/EGDMA)‐SA) beads, using glutaric dialdehyde as a coupling agent. Both affinity poly(GMA/MMA/EGDMA)‐based beads were used in HIgG adsorption/desorption studies under defined pH, ionic strength, or temperature conditions in a batch reactor, using acid‐treated poly(GMA/MMA/EGDMA) beads as a control system. The poly(GMA/MMA/EGDMA)‐SA affinity beads resulted in an increase in the adsorption capacity to HIgG compared with the aminated counterpart (i.e., poly(GMA/MMA/EGDMA)‐AA). The maximum adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA affinity beads were found to be 112.36 and 142 mg g^?1, and the affinity constants (K_d), evaluated by the Langmuir model, were 2.48 × 10^?7 and 6.98 × 10^?7M, respectively. Adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA were decreased with HIgG by increasing the ionic strength adjusted with NaCl. Adsorption kinetic of HIgG onto both affinity adsorbents was analyzed with first‐ and second‐order kinetic equations. The first‐order equation fitted well with the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 672–679, 2007     

Artificial neural networks for the cost estimation of stamping dies

Although artificial neural networks (ANN) are more known in the field of image recognition and forecasting, cost estimation has become another emerging area in recent years. In this study, the establishment of an intelligent system was attempted for forecasting the total cost of sheet metal stamping dies. In this context, where the cost of stamping dies is estimated with a conventional approach which has been applied in the company up to now, the ANN and multiple regression analysis and the performance of the three cost-estimation models are examined. The examinations are based on the data of previous costs and use a number of critical criteria which are decided by experienced tool makers and engineers from every level of the organization of the seven companies which produce stamping dies. The comparative study reveals that the ANN system outperforms the traditional linear regression analysis model and conventional approach used for cost estimation. Thus, it is possible for firms which produce stamping dies to obtain a fairly accurate prediction with an ANN model and determined criteria.     

Kinetic of thermal degradation of poly(isobornyl methacrylate)

The kinetic of the thermal degradation of poly(isobornyl methacrylate) (PIBORNMA) was investigated by thermo gravimetric (TG) analysis at different heating rates. TG curves showed that the thermal decomposition of PIBORNMA occurred in one stage. The apparent activation energies of thermal decomposition of PIBORNMA was determined by Tang, Flynn-Wall-Ozawa (FWO), Kissenger–Akahira–Sunose (KAS) and Coats-Redfern methods and the values were 80.30, 84.69, 79.81 and 84.413 kJ/mol, respectively. The mechanism function and pre-exponential factor was determined by master plots method.     

Effects of cyclization and pendant vinyl group reactivity on the swelling behavior of polyacrylamide gels

A series of polyacrylamide (PAAm) gels were prepared by free-radical crosslinking copolymerization of acrylamide and N,N′-methylenebis(acrylamide) (BAAm) in water at various crosslinker (BAAm) and chain transfer agent (isopropyl alcohol, IPA) concentrations. It was shown that only 5% of the crosslinker used in the feed forms effective crosslinks in the final hydrogels. At BAAm contents as high as 3 mole%, the equilibrium swelling ratio of the gels in water is independent of the crosslinker content in the feed. This is due to the prevailing multiple crosslinking reactions during the gel formation process. At a fixed crosslinker content, the onset of gelation is shifted towards higher conversions and reaction times as the amount of IPA increases. Addition of IPA in the monomer mixture also increases the equilibrium swelling ratio of PAAm gels. It was shown that the gel crosslinking density increases on rising IPA concentration in the feed due to the increasing rate of intermolecular crosslinking reactions. Received: 30 May 1997/Accepted: 26 June 1997     

Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends

In this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007     

How Does Software Visualization Contribute to Software Comprehension? A Grounded Theory Approach

Despite their ability to synthesize vast amounts of information, software visualization tools are not widely adopted in the software engineering industry. In an effort to investigate the underlying reasons, we conducted a usability study to investigate the affordances of software visualization techniques for the maintenance of complex software systems. Expert programmers were asked to carry out programming tasks with or without using a software visualization tool while their screens and eye gaze patterns were recorded. Statistical analysis of task performance data showed that participants who used the software visualization tool outperformed the control group in terms of task completion time and accuracy. However, quantitative analysis of performance measures did not reveal in what ways software visualizations contributed to this improvement. In an effort to identify the cognitive strategies that underlie this quantitative performance difference, process models grounded in qualitative analysis of eye-tracking data were constructed. The process models indicated that software visualizations guided the subjects in the experiment group toward following specific software comprehension strategies, which account for the difference observed in task performance data.     

A new hyper-heuristic as a general problem solver: an implementation in HyFlex

This study provides a new hyper-heuristic design using a learning-based heuristic selection mechanism together with an adaptive move acceptance criterion. The selection process was supported by an online heuristic subset selection strategy. In addition, a pairwise heuristic hybridization method was designed. The motivation behind building an intelligent selection hyper-heuristic using these adaptive hyper-heuristic sub-mechanisms is to facilitate generality. Therefore, the designed hyper-heuristic was tested on a number of problem domains defined in a high-level framework, i.e., HyFlex. The framework provides a set of problems with a number of instances as well as a group of low-level heuristics. Thus, it can be considered a good environment to measure the generality level of selection hyper-heuristics. The computational results demonstrated the generic performance of the proposed strategy in comparison with other tested hyper-heuristics composed of the sub-mechanisms from the literature. Moreover, the performance and behavior analysis conducted for the hyper-heuristic clearly showed its adaptive characteristics under different search conditions. The principles comprising the here presented algorithm were at the heart of the algorithm that won the first international cross-domain heuristic search competition.     

Satisfying agent goals by executing different task semantics: HTN, OWL-S or plug one yourself

In this paper, we propose a plan execution architecture which supports different task semantics. This way, each goal that is identified during the deliberation cycle of an agent can be satisfied through tasks defined in different semantics. The capability of supporting different task semantics provides two main advantages. The first advantage is the reuse of legacy artifacts within agent plans. The second advantage is simplifying the adaptation of an agent architecture to different standards of a business organization. In order to integrate various task semantics within a plan execution architecture, we have used a smoothly revised version of a previously articulated workflow model into which different task semantics would be reduced before execution. We have integrated hierarchical task network and OWL-S semantics into our plan execution architecture to test the strength of it in terms of support for executing different task semantics in an agent architecture. We think that such a plan execution architecture will contribute to the industrialization of agent architectures.     

Participatory design in interactive media design education for the solution of unfamiliar design problems: a case study on a disabling environment and an emerging technology

This paper investigates the effectiveness of participatory design study in rendering the students' capability of producing innovative design solutions to problems with uncertainties with which the students have no prior experience. At the project, the students were given a case to work on augmented reality technology with which they had no previous experience and design a tactical interface for sailing boats, a field they had no competence in. While the students were asked to develop proposals for this design problem with which they were inexperienced, a two-stage study was conducted to enable them to produce ideas on the topic. This paper discusses the impacts of such a participatory method in terms of design education. At the end of our study, it was observed that the students were positively influenced by the process in which they worked collaboratively with an expert user group.