Антипсихотические лекарственные средства. Риск развития экстрапирамидных нарушений и/или абстинентного синдрома у новорожденных, матери которых принимали вышеуказанные лекарственные средства в течение третьего триместра беременности

ЛЕКАРСТВАТРАНКВИЛИЗАТОРЫ БОЛЬШИ

Considering the benefits of asphalt modification using a new technical life cycle assessment framework

Asphalt mixtures properties can be enhanced by modifying it with additives. Even though the immediate benefits of using polymers and waxes to modify the binder properties are rather well documented, the effects of such modification over the lifetime of a road are seldom considered. To investigate this, a newly developed open technical life cycle assessment (LCA) framework was used to determine production energy and emission limits for the asphalt additives. The LCA framework is coupled to a calibrated mechanics based computational framework that predicts the in-time pavement performance. Limits for production energy of wax and polymers were determined for the hypothetical case studies to show how LCA tools can assist the additives manufacturers to modify their production procedures and help road authorities in setting ‘green’ limits to get a real benefit from the additives over the lifetime of a road. From the detailed case-studies, it was concluded that better understanding of materials will lead to enhanced pavement design and could help in the overall reduction of energy usage and emissions. First published online: 02 Sep 201

Laboratory investigation of bitumen based on round robin DSC and AFM tests

In the past years a wide discussion has been held among asphalt researchers regarding the existence and interpretation of observed microstructures on bitumen surfaces. To investigate this, the RILEM technical committee on nano bituminous materials 231-NBM has conducted a round robin study combining differential scanning calorimetry (DSC) and Atomic Force Microscopy (AFM). From this, methods for performing DSC and AFM tests on bitumen samples and determination of the influence of wax on the observed phases, taking into account thermal history, sample preparation and annealing procedure, are presented and critically discussed. DSC is used to measure various properties and phenomena that indicate physical changes such as glass transition temperature (T g) and phase transition such as melting and crystallization. In the case of existence of wax, either natural or synthetic, it can further indicate the melting point of wax, that could be used to determine wax content. The results from seven laboratories show that T g temperatures obtained from the heating scans are more repeatable and easier to obtain in comparison to the cooling scans. No significant difference was noted for T g's obtained from the first and second heating scans. AFM is an imaging tool used to characterize the microstructures on a bituminous surface. Using AFM three phases in the materials with wax could be distinguished. The changes in the phases observed with AFM for increases in temperature were correlated with the DSC curve, and it could be established that the so called "Bee” structure disappeared around the melting peak in the DSC curve. Thus, this research has confirmed the relation between the microstructures on a bitumen surface and the wax content

Developing a System Dynamics Model from Perceptions : A Case Study of Perspectives on Road Procurement in Sweden

As a public organisation, road administrations have the responsibility to improve the road construction process. However, the changes in such process involve a number of the stakeholders, who have different perceptions about what is most important in the road construction process. Perspectives on the necessity and nature of change will differ too. In order to provide an environment in which the potential consequences of changes in procurement can be tested, it is important to develop a model that simulates the process, especially the social part of the system. To achieve this, the model requires perceptions of stakeholders. The paper presents a new framework that obtains worldviews of the stakeholders in the complex adaptive system and transforms them into a System Dynamics model. As a result, a computational model is developed to observe the behaviour of stakeholders in the system. The model can become a tool for testing policies in the complex adaptive system.QC 20170922PaveTheGam

Perspectives of Stakeholders on Road Procurements : In search of Procurement Aspects using Q Methodology

Nowadays much emphasis is given to innovative procurement in the road construction sector. However, typical discussions about it do not focus on all the stakeholders involved in the process and all aspects. However, one cannot forget that procurement is a complex system, and everyone’s perspective is important for success. This paper looks at the worldviews of stakeholders in the road construction industry. The Q methodology is used to analyse the subjectivity of the worldviews. As a result, it is possible to look deeper into the perspectives and to see what each stakeholder sees as most important, and also to compare different worldviews among stakeholders.QC 20170922</p

A Research Agenda for Green Procurement of Infrastructures

Construction and maintenance of road infrastructure is a major source of emissions and energy usage. Procuring green roads, however, is neither commonplace nor trivial to implement. New ways to enhance the green procurement of roads are therefore needed, and can potentially involve life cycle assessment and green labelling methods. Considering the complexity of the pavement industry sector with its many actors and structures, implementing such innovations in the procurement process is surrounded with a series of uncertainties. The current paper formulates a research agenda for green procurement of roads by looking into potential mechanisms for future procurement. Given the objective of green procurement, the paper is focusing on the question what are the short term and long term effects of potential combinations of life cycle assessment principles and procurement process structures on infrastructure costs, risks, environmental impact and the structure of the road sector. Six different approaches are presented and reviewed for relevant earlier work in the literature. Based upon the complexities found, the authors discuss the challenges in finding a matching single research method. A solution is proposed for a holistic approach using gaming simulation, since it allows evaluating the procurement of infrastructure as a complex adaptive system.QC 20150108</p

Polymer modification of bitumen : Advances and challenges

Advances and challenges in the field of bitumen polymer modification for road construction during the last 40 years are reviewed in this paper. The history of bitumen polymer modification is described chronologically. Some popular plastomers and thermoplastic elastomers in bitumen modification are discussed regarding their advantages and disadvantages, including polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate (EVA), ethylene-butyl acrylate (EBA), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS) and styrene-ethylene/butylene-styrene (SEBS). Although these polymers all improve bitumen properties to some extent, there are still some drawbacks limiting the future development of bitumen polymer modification, such as high cost, low ageing resistance and poor storage stability of polymer modified bitumen (PMB). Researchers attempted various ways to remove these drawbacks. Some technical developments for removing drawbacks are reviewed in this paper, including saturation, sulfur vulcanization, adding antioxidants, using hydrophobic clay minerals, functionalization and application of reactive polymers. The future development of polymers for bitumen modification is analyzed as well. Since it is currently challenging to perfectly achieve all expected PMB properties at the same time, some compromised recommendations are given in this paper, among which greatly enhancing the properties with an acceptably high cost, significantly reducing the cost with relatively poor properties and their combinations. Functionalization is emphasized as a promising way to enhance the properties of currently used polymers and develop new-type polymer modifiers with much greater success in the future. It is also recommended that future research on bitumen polymer modification focuses more on function development towards enhancing: adhesion with aggregates, long-term performance and recyclability.QC 20140612</p

Modelling and numerical simulation of phase separation in polymer modified bitumen by phase-field method

In this paper, a phase-field model with viscoelastic effects is developed for polymer modified bitumen (PMB) with the aim to describe and predict the PMB storage stability and phase separation behaviour. The viscoelastic effects due to dynamic asymmetry between bitumen and polymer are represented in the model by introducing a composition-dependent mobility coefficient. A double-well potential for PMB system is proposed on the basis of the Flory-Huggins free energy of mixing, with some simplifying assumptions made to take into account the complex chemical composition of bitumen. The model has been implemented in a finite element software package for pseudo-binary PMBs and calibrated with experimental observations of three different PMBs. Parametric studies have been conducted. Simulation results indicate that all the investigated model parameters, including the mobility and gradient energy coefficients, interaction and dilution parameters, have specific effects on the phase separation process of an unstable PMB. In addition to the unstable cases, the model can also describe and predict stable PMBs. Moreover, the phase inversion phenomenon with increasing polymer content in PMBs is also well reproduced by the model. This model can be the foundation of an applicable numerical tool for prediction of PMB storage stability and phase separation behaviour.QC 20160620</p