Emerging Workplaces in Post-Functionalist Cities

ABSTRACT

This paper explores new types of workplaces that are emerging due to the growing flexibility in work arrangements and the use of information and communication technologies. In addition to home and office, third places, such as libraries and coffee shops, are increasingly used as temporary workplaces. Moreover, there is a proliferation of co-working spaces that are designed as temporary working locations. Thus, the boundaries between traditional urban functions have become blurred; different functions co-exist in the same spaces, and new functionalities emerge as people take spaces into new uses. We may call our cities “post-functionalist,” ones that are no longer based only on predetermined and designed functions. However, there has been little research on the spatial characteristics of these new workplaces as well as on the social features within these places. These phenomena have been empirically studied through observational studies, interviews, and spatial analyses of three such sites: Café Köket, Meetingpoint, and Helsinki Think Company in the city center of Helsinki. The results reveal new forms of appropriation of public and semi-public spaces for working purposes that have not yet been analyzed in the context of existing urban policies and practices. The findings provide input for future visions and the planning of new workplaces.     

Electrical sintering of nanoparticle structures

A method for sintering nanoparticles by applying voltage is presented. This electrical sintering method is demonstrated using silver nanoparticle structures ink-jet-printed onto temperature-sensitive photopaper. The conductivity of the printed nanoparticle layer increases by more than five orders of magnitude during the sintering process, with the final conductivity reaching 3.7 × 10(7)?S?m(-1) at best. Due to a strong positive feedback induced by the voltage boundary condition, the process is very rapid-the major transition occurs within 2?μs. The best obtained conductivity is two orders of magnitude better than for the equivalent structures oven-sintered at the maximum tolerable temperature of the substrate. Additional key advantages of the method include the feasibility for patterning, systematic control of the final conductivity and in situ process monitoring. The method offers a generic tool for electrical functionalization of nanoparticle structures.     

Equilibrium sampling of persistent and bioaccumulative compounds in soil and sediment: comparison of two approaches to determine equilibrium partitioning concentrations in lipids

The equilibrium sampling in silicone is increasingly applied to measure freely dissolved concentrations and chemical activities within bioaccumulation research of hydrophobic organic chemicals. Two equilibrium methods were applied to PCB-contaminated soil and sediment, and directly calibrated with respect to equilibrium partitioning concentrations in lipids (C(lipid,partitioning)): (i) Solid phase microextraction in the headspace above the sample (HS-SPME) required optimization for its application to PCBs, and it was calibrated above external partitioning standards in olive oil. (ii) Equilibrium sampling with internally coated glass jars with varying thicknesses of silicone (PDMS) resulted in proportionality between coating and analyte mass, which confirmed several validity criteria. C(lipid,partitioning) was here determined as product of PDMS concentration and PDMS to lipid partition ratio. The results of the two methods were in good agreement and thus validated each other. Finally, the coated glass jar method was applied to field sediment containing invertebrates, which lead to C(lipid,partitioning) that were about two times higher than measured lipid-normalized concentrations in the organisms. Temperature differences and animal lipid structure were discussed as possible reasons for this discrepancy. Both methods combine high analytical performance, reduced equilibration times and new calibration possibilities, which makes them suited for bioaccumulation research and environmental monitoring.     

Effects of wood flour modification on the fire retardancy of wood–plastic composites

Wood–plastic composites (WPC) are materials that combine the properties of wood and plastics. Both are flammable organic materials. Fire safety is considered to be an important issue especially in construction applications. In this research, the fire safety of WPC material is improved by using modification chemicals for wood flour treatment. The effectiveness of the modification is studied with a cone calorimeter device. Mechanical properties and water absorption are also examined. Scanning electron microscopy is used for analyzing the interfacial adhesion of the fiber and matrix. The results show that the fire performance of WPC material can be enhanced through wood modification, which can also improve the moisture uptake performance and the interfacial adhesion of the material. However the mechanical properties decrease as a result of modification with the used fire retardants.     

Rapid electrochemiluminoimmunoassay of human C-reactive protein at planar disposable oxide-coated silicon electrodes

Electrochemiluminescence (ECL) of aromatic Tb(III) chelates at thin insulating film-coated electrodes provides a means for extremely sensitive detection of Tb(III) chelates and also of biologically interesting compounds if these chelates are used as labels in bioaffinity assays. The suitability of silicon electrodes coated with thermally grown silicon dioxide film as disposable working electrodes in sensitive time-resolved ECL measurements is demonstrated, and a rapid electrochemiluminoimmunoassay (ECLIA) of human C-reactive protein (hCRP) is described. Tb(III) chelate labels can be detected almost down to picomolar level, and the calibration curve of these labels covers more than 6 orders of magnitude of chelate concentration. The calibration curve of the present immunometric hCRP assay was found to be linear over a wide range, approximately 4 orders of magnitude of hCRP concentration, the detection limit of the protein being 0.3 ng mL(-1) (mean background + 2SD) on CV values of about 10-30%, depending on the immunoassay incubation time. In the ECLIA measurements, different incubation times were tested from 15 min (giving above-mentioned performance) to as short as only 2 min, which still gave successful results with approximately 20,000 times better detection limit levels than traditional commercial assay methods. During the ECLIA process, also the Si electrode surface morphology was also investigated by atomic force microscope monitoring.     

Data generative machine learning model for the assessment of outdoor thermal and wind comfort in a northern urban environment

Predicting comfort levels in cities is challenging due to the many metric assessment. To overcome these challenges, much research is being done in the computing community to develop methods capable of generating outdoor comfort data. Machine Learning (ML) provides many opportunities to discover patterns in large datasets such as urban data. This paper proposes a data-driven approach to build a predictive and data-generative model to assess outdoor thermal comfort. The model benefits from the results of a study, which analyses Computational Fluid Dynamics (CFD) urban simulation to determine the thermal and wind comfort in Tallinn, Estonia. The ML model was built based on classification, and it uses an opaque ML model. The results were evaluated by applying different metrics and show us that the approach allows the implementation of a data-generative ML model to generate reliable data on outdoor comfort that can be used by urban stakeholders, planners, and researchers.