Helsinki University of Technology

About: Helsinki University of Technology is a based out in . It is known for research contribution in the topics: Artificial neural network & Finite element method. The organization has 8962 authors who have published 20136 publications receiving 723787 citations. The organization is also known as: TKK & Teknillinen korkeakoulu.

Self-assembled polymeric solid films with temperature-induced large and reversible photonic-bandgap switching.

Abstract: In aqueous solutions the response of polymers and biological matter to external conditions, such as temperature and pH, is typically based on the hydrophobic/hydrophilic balance and its effects on the polymer conformation. In the solid state, related concepts using competing interactions could allow novel functions. In this work we demonstrate that polymeric self-assembly, reversibility of hydrogen bonding, and polymer-additive phase behaviour allow temperature response in the solid state with large and reversible switching of an optical bandgap. A complex of polystyrene-block-poly(4-vinylpyridinium methanesulphonate) and 3-n-pentadecylphenol leads to the supramolecular comb-shaped architecture with a particularly long lamellar period. The sample is green at room temperature, as an incomplete photonic bandgap due to a dielectric reflector is formed. On heating, hydrogen bonds are broken and 3-n-pentadecylphenol additionally becomes soluble in polystyrene, leading to a sharp and reversible transition at approximately 125 degrees C to uncoloured material due to collapse of the long period. This encourages further developments, for example, for functional coatings or sensors in the solid state.

Solving the last mile issue: reception box or delivery box?

Abstract: One of the biggest challenges in B2C e‐commerce is the so‐called “last mile”, the home delivery service for the customer. Particularly in electronic grocery shopping it is difficult to combine profitability and high service level. The authors’ simulations suggest that the unattended reception of goods reduce home delivery costs considerably, by up to 60 percent. Unattended delivery has not been widely used because it requires investments and commitment from the customer. The two main approaches to unattended delivery are the reception box concept and the delivery box concept. The reception box is a refrigerated, customer‐specific reception box installed at the customer’s garage or home yard. The delivery box is an insulated secured box equipped with a docking mechanism. The reception box concept results in more effective home delivery transportation and the delivery box concept in smaller investment to achieve unattended receipt. This article assesses these two different concepts. The cost savings in transportation are analysed using simulation. The operational cost savings are compared to the respective investments required to calculate the payback period. Both concepts proved to be feasible but which one works better is not only a question of financial justification. The possible additional value to customers and overall suitability to the market must also be considered.