Automatic Palletizing of Concrete Pavement Blocks: An Algorithm for Near-Optimal Assembly

Palletizing concrete pavement blocks is a labor-intensive task that requires high levels of workmanship, skill, and concentration. This article proposes an automatic system in which palettes with required design patterns are assembled automatically off-site and then shipped to the construction site. The efficiency of the assembly process can be improved by incorporating automatic equipment consisting of assembly heads and feeders. An algorithm was developed to determine the optimal layout of the feeders (of different blocks) around the palette and the exact assembly sequence of each layer of blocks. Experimental results show that the algorithm is near optimal and that the solutions provided by it reduce palletizing cycle time for various patterns and sizes of concrete block by 20 to 30 percent.     

Solar energy transmittance of translucent samples: A comparison between large and small integrating sphere measurements

Optical transmittance and reflectance of a translucent plastic PTFE film have been measured over the solar wavelength range using different integrating spheres. The same sample has been measured with small and large spheres and the total solar transmittance has been obtained from both broad band measurements and from integration of spectral data. The fact that the sum of reflectance and transmittance often exceeds 100% shows that all types of spheres tend to overestimate the transmittance of this highly scattering sample. This error can be attributed to the sphere geometry in combination with the light scattering properties of the sample, and unless proper correction of recorded data is carried out the error may be as large as 5–10%. Some specific errors are presented and an approximate correction procedure is suggested.These results show that there is a need for a transmittance standard which can be used to calibrate integrating spheres. Such a standard with negligible thickness would be especially useful for measurements with large, broadband integrating spheres, but would also be helpful for the correct handling of data from small spectral instruments.     

Independent block identification in multivariate time series

In this‐30 work we propose a model selection criterion to estimate the points of independence of a random vector, producing a decomposition of the vector distribution function into independent blocks. The method, based on a general estimator of the distribution function, can be applied for discrete or continuous random vectors, and for i.i.d. data or dependent time series. We prove the consistency of the approach under general conditions on the estimator of the distribution function and we show that the consistency holds for i.i.d. data and discrete time series with mixing conditions. We also propose an efficient algorithm to approximate the estimator and show the performance of the method on simulated data. We apply the method in a real dataset to estimate the distribution of the flow over several locations on a river, observed at different time points.     

Supporting users in finding successful matches in reciprocal recommender systems

User Modeling and User-Adapted Interaction - Online platforms which assist users in finding a suitable match, such as online-dating and job recruiting environments, have become increasingly popular...     

Review and analysis of performance metrics of droplet microfluidics systems

Droplet microfluidics has enabled many recent applications in high-throughput screening and diagnostics. Little work has been done, however, to analyze the performance of droplet-based assays. This review aims to apply what is known in the literature to the analysis of the performance metrics of droplet-based assays, with specific relevance to diagnostic and biomedical applications based on two processes: enzymatic reactions and cell culture in droplets. By considering the physical scaling of individual processes—droplet generation, reaction kinetics, cell growth, and droplet interrogation—it is possible to extract a practical relationship between input parameters (e.g., droplet size and droplet polydispersity) and the output characteristics (e.g., throughput, dynamic range, and accuracy) of the assay. This review can serve as a guide to the design of droplet-based assays for achieving desired performance. While the focus is on assays based on enzymatic reactions and cell cultures, a similar analysis can be applied to other assays based on polymerase chain reaction and the detection of nucleic acids.     

Effektive Stofftrennung in Gas‐ und Flüssigphase durch selektive Adsorption

Adsorption is a versatile tool for the separation of low abundant molecules from complex mixtures. The affinity and selectivity of the adsorbents are crucial parameters for the efficiency of the separation process. This work provides an overview of the basic adsorption mechanisms and illustrates their relevance for technical applications based on own experimental data in bioprocess, environmental and safety engineering. Distinctive features between the adsorption from the gas and fluid phase, respectively, the differences between small molecules and interacting biomacromolecules are presented.     

Estimation of exposure to sunlight of the liner under a tiled roof

One construction for a pitched roof is to use tiles on battens, with a liner attached below the battens. The shape of some types of tiles is such that, at each corner where four tiles overlap, a small gap is formed. At certain positions of the sun solar radiation can penetrate through these gaps and strike the liner, accelerating its degradation. The purpose of this study is to estimate the extent and duration of the exposure. A typical gap is modelled in a ray-tracing program and the size and position of the illuminated area on the liner is calculated for given directions of the light beam relative to the roof. Analytic expressions for the size of the illuminated area are obtained using a thick slit model. The accuracy of the model was assessed by some experimental measurements. The exposure over one year of the roof liner was calculated using the Design Reference Year for Copenhagen, Denmark. Simulations were carried out for a roof tilted at 25°, 35° or 45°, facing SE, S, SW or W. For the particular roof construction and gap studied, the maximum annual exposure of a 25 mm² piece of the liner placed 150 mm below the gap (corresponding to about 100 mm below the base of the tiles) is about 140 kJ m⁻² to UV-B and 4.2 MJ m⁻² to UV-A radiation. Variations in tile size and misalignment of tiles could lead to other gap shapes and sizes, possibly leading to greater exposure. Constructions with the liner placed closer to the tiles would also lead to greater exposures. However the method developed in this study could form the basis of a standard method of assessment.     

Cylindrical Silicon-on-Insulator Microdosimeter: Design, Fabrication and TCAD Modeling

A novel silicon-on-insulator (SOI) microdosimeter has been designed and fabricated using planar processing techniques to realise a device with a micron-scale well-defined sensitive volume. Cylindrical structures were employed to allow for an improved definition of the average chord length of the sensitive volume over that of previous elongated parallelepiped solid-state detector designs. The structures were manufactured on individual silicon mesas situated on top of a buried oxide insulating layer. The mesa design eliminated lateral charge diffusion. Two kinds of test structures were designed with sensitive region widths of 2 mum and 10 mum. In addition, an array of 900 cylindrical diodes was fabricated to increase the charge collection statistics. TCAD (Technology Computer Aided Design) modeling of the electrostatic potential and electric field profile of the cylindrical microdosimeter was carried out to obtain 3D potential and electric field profiles. The modeling revealed a radial electric field within the cylindrical-shaped sensitive volume with a 1/r dependence. While the electric field at the core of the cylindrical microdosimeter was not sufficiently high to induce avalanche signal multiplication, the higher electric field at the core should still assist in the measurement of low linear-energy transfer (LET) events.