Comparison of nine common coffee extraction methods: instrumental and sensory analysis

The preparation of a cup of coffee may vary between countries, cultures and individuals. Here, an analysis of nine different extraction methods is presented regarding analytical and sensory aspects for four espressi and five lunghi. This comprised espresso and lungo from a semi-automatic coffee machine, espresso and lungo from a fully automatic coffee machine, espresso from a single-serve capsule system, mocha made with a percolator, lungo prepared with French Press extraction, filter coffee and lungo extracted with a Bayreuth coffee machine. Analytical measurements included headspace analysis with HS SPME GC/MS, acidity (pH), titratable acidity, content of fatty acids, total solids, refractive indices (expressed in °Brix), caffeine and chlorogenic acids content with HPLC. Sensory analysis included visual, aroma, flavor and textural attributes as well as aftersensation. The technical differences in the extraction methods led to a higher concentration of the respective quantities in the espressi than in the lunghi. Regarding the contents per cup of coffee, the lunghi generally had a higher content than the espressi. The extraction efficiency of the respective compounds was mainly driven by their solubility in water. A higher amount of water, as in the extraction of a lungo, generally led to higher extraction efficiency. Comparing analytical data with sensory profiles, the following positive correlations were found total solids ? texture/body, headspace intensity ? aroma intensity, concentrations of caffeine/chlorogenic acids ? bitterness and astringency.     

Testing of Newly Developed Functional Surfaces Under Pure Sliding Conditions

The employment of surface texturing for improved tribological contacts has spread over the years. The possibilities of designing and manufacturing textured surfaces with predetermined geometries have multiplied as well as the need of performing experimental laboratory tests before applying the surfaces in an industrial context. In this paper, a number of experimental tests were performed using a novel test rig, called axial sliding test, simulating the contact of surfaces under pure sliding conditions. The aim of the experiments is to evaluate the frictional behavior of a new typology of textured surfaces, the so-called multifunctional surfaces, characterized by a plateau area able to bear loads and a deterministic pattern of lubricant pockets. Six surface typologies, namely three multifunctional and three machined using classical processes, were chosen to slide against a mirror-polished counterpart. A number of experiments were carried out at different normal pressures employing for all specimens the same reciprocating movement and the same lubrication. The measured friction forces were plotted against the incremental normal pressure, and the friction coefficients were calculated. The results comparison showed clearly how employing multifunctional surfaces can reduce friction forces up to 50 % at high normal loads compared to regularly ground or turned surfaces. Friction coefficients approximately equal to 0.12 were found for classically machined surfaces, whereas the values were 0.06 for multifunctional ones. All the specimens were characterized before and after testing. Wear occurrence was not detected on the tested surfaces except for the mirror-polished one which underwent all the experiments.     

Potential for acrylamide formation in potatoes: data from the 2003 harvest

Reducing sugars, free amino acids, and the potential for acrylamide formation were determined in more than 50 potato samples from the 2003 harvest in Switzerland. The reducing sugar content strongly correlated with acrylamide, whereas no correlation was found between acrylamide and free asparagine or the pool of free amino acids. The reducing sugar contents and the acrylamide potentials were higher in most of the cultivars tested than in the samples from 2002. This was probably due to the hot and dry summer of 2003. Monitoring sugars and amino acids during heating at 120 °C and 180 °C showed that glucose and fructose reacted much faster than sucrose and the amino acids. Glutamine was consumed to a larger extent than any of the other amino acids. During prolonged storage, the reducing sugars decreased considerably while only moderate changes in the free amino acids were observed. Altogether, glucose and fructose remain the critical factors for acrylamide formation in potatoes and represent the most feasible way of reducing the formation of acrylamide in potato products.     

Impact and control of network QoS on smart grid controlled electrical vehicle charging

Novel, networked information-rich control systems are emerging to provide a stable and cost-efficient operation of future electricity distribution grids. However, the dependence on fault-prone, low-cost, and heterogeneous network technologies and architectures challenges the grid control quality. In this work, we study the impact of varying network QoS for M2M connectivity on the low voltage grid operation in an electrical vehicle charging scenario. The analyzed charging control system relies on: (a) grid power sensing using smart meters via high latency power line communication and, (b) charging point actuation commands disseminated via unreliable wireless links (IEEE 802.11). Based on emulation results, we quantify the maximum acceptable meter reading delay from network transmission that sufficiently minimizes load prediction error. Further, based on the introduction of a timed reliable communication protocol, it is shown how changing the trade-off in QoS parameters of delay, loss and information inconsistency can be applied to overcome degradation of controller performance.     

Informing General CSCW Product Development through Cooperative Design in Specific Work Domains

Cooperative analysis and design is often considered only to beapplicable in settings where a system is being developed solely for theuser participants in the process. This paper, however, argues that thereare quite good prospects in applying cooperative analysis and designtechniques in specific use settings to inform development of general CSCWproducts. We describe and discuss the application of cooperative –i.e., participatory – analysis and design techniques in a projectdeveloping a general cooperative hypermedia framework as well as specifichypermedia applications to support sharing of materials in the engineeringdomain. In our project, a single engineering company (Great Belt Link Ltd.)was chosen as the user organization. The paper summarizes the process fromobservational studies, over a future workshop and cooperative prototypingactivities, to a pilot installation. We describe how these activitiesinformed the general hypermedia framework and application design. Usescenarios and prototypes with example data from the users' daily work wereused as sources both to trigger design ideas and new insights regarding workpractice. Common participants in specific activities and general developmentactivities supported transfer of work domain knowledge into general featuresof the product being developed. Mutual challenging characterized theinteraction between specific cooperative analysis and design activities andgeneral development activities. Prototypes, scenarios, materials from thework practice, and concise bullet list summaries were used as mediatingartifacts in this interaction rather than comprehensive requirement anddesign specifications.     

Physical hypermedia: Augmenting physical material with hypermedia structures

This paper introduces the notion of physical hypermedia, addressing the problem of organizing material in mixed digital and physical environments. Based on empirical studies, we propose concepts for collectional actions and meta-data actions, and present prototypes combining principles from augmented reality and hypermedia to support organization of mixtures of digital and physical materials. Our prototype of a physical hypermedia system is running on an augmented architect's desk and digital walls utilizing Radio Frequency Identifier (RFID) tags as well as visual tags tracked by cameras. It allows users to tag physical materials, and have these tracked by readers (antennas) that may become pervasive in our work environments. In the physical hypermedia system, we work with three categories of RFID tags: simple object tags, collectional tags, and tooltags invoking operations such as grouping and linking of physical material. In addition, we utilize visual ARToolKit tags for linking and navigating 3D models on a physical desk. Our primary application domain is architecture and design, and so we discuss the use of augmented collectional artifacts primarily for this domain.     

Acrylamide in almond products

Acrylamide was determined in 86 different almond products, such as roasted almonds, almond-containing bakery products, raw almonds, and marzipan. The highest acrylamide concentrations were found in dark roasted almonds, while only moderate acrylamide contents were determined in bakery products. Roasting experiments under different process conditions showed that acrylamide increases with time and that temperature has a much stronger effect on acrylamide formation than time. During roasting reducing sugars are consumed faster and to a larger extent than free asparagine, suggesting that the content of reducing sugars may be a critical factor for acrylamide formation in roasted almonds. Acrylamide was found to decrease in roasted almonds during storage at room temperature.     

A New Rig for Testing Textured Surfaces in Pure Sliding Conditions

Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, as demonstrated by the development and spread of plateau-honed surface for cylinder liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper, a new test rig simulating pure sliding conditions is presented, dubbed axial sliding test. It presents four major components: a rod, a sleeve, a housing and a stripwound container. The rod and the sleeve are the two surfaces in relative sliding motion; the stripwound container maintains a constant, but adjustable normal pressure, and the housing serves as interface between the sleeve and the container. For carrying out the test, two machineries are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Preliminary tests are carried out involving a multifunctional and a fine-turned rod against a mirror-polished sleeve. Qualitatively, the multifunctional surfaces improve the friction conditions, but a more structured test campaign is required. It is furthermore assessed the repeatability of the test device, in order to rely on the results obtained. Ten repetitions made at the same pressure using the fine-turned rod displayed good repeatability of the force results both in terms of average values and trends.