Optimization-Based Network Identification for Thermal Transient Measurements

Network identification by deconvolution is a proven method for determining the thermal structure function of a given device. The method allows to derive the thermal capacitances as well as the resistances of a one-dimensional thermal path from the thermal step response of the device. However, the results of this method are significantly affected by noise in the measured data, which is unavoidable to a certain extent. In this paper, a post-processing procedure for network identification from thermal transient measurements is presented. This so-called optimization-based network identification provides a much more accurate and robust result compared to approaches using Fourier or Bayesian deconvolution in combination with Foster-to-Cauer transformation. The thermal structure function obtained from network identification by deconvolution is improved by repeatedly solving the inverse problem in a multi-dimensional optimization process. The result is a non-diverging thermal structure function, which agrees well with the measured thermal impedance. In addition, the associated time constant spectrum can be calculated very accurately. This work shows the potential of inverse optimization approaches for network identification.

Modelling and Analysis of a Solid Waste Composter for Urban Houses

Disposal of waste is an important issue faced by sanitation agencies, especially in India, where the volume of waste generated has been increasing rapidly over the last few years. According to the Ministry of Housing and Urban Affairs, as of January 2020, 147,613 metric tonnes (MT) of solid waste is generated per day in the country. Part of the waste that is expunged on a daily basis from homes, is food and other kitchen waste, which are biodegradable or compostable. In rural areas, such waste is disposed of in landfills, such that they get decomposed to form compost that is used as manure for crops. But this is not feasible in large cities where empty land, as well as the time required for waste to get converted into compost, is in short supply. Composting is a proven method to reduce the volume of waste, to almost 15-20% of its original amount. Therefore, this work is focused on designing an electric composter that could decompose waste artificially, and is compact, efficient, odourless, and easy to operate. This product can thus manage biodegradable waste at the source of its generation, and effectively supplant the wastebasket in a kitchen by occupying no greater space than the latter. The yield of compost would also provide nutritive natural fertilizer to homes wherein kitchen gardens or terrace farms have been set up, as well as promote the creation of the same wherever space is available. In this paper, the important parameters involved in the design of composter, including geometry parameters and the ones of operational significance such as speed and number of blades of agitator and bin temperature, have been discussed thoroughly, along with providing an understanding of the processes and considerations necessitated.

Eco-Friendly Protective Coating to Extend the Life of Art-Works and Structures Made in Porous Stone Materials

The application of hydrophobic treatments to stone surfaces is the most common proven method to prevent, or at least limit, the degradation of stone-made constructions and artworks brought about by the ingress and action of water, in particular in the case of very porous stone materials. To avoid the use of protective products containing harmful solvents, new green products have been proposed. In this paper, an eco-friendly hydrophobic coating, based on a fluorine polymer dispersed in water, was deeply analyzed to evaluate its protective properties, especially for very porous stone substrates. To this aim, a wide characterization of treated and untreated Lecce stone elements, i.e., a stone typical of the Apulia region, was carried out to assess the optimum required amount, the effectiveness and the protective capability, even against graffiti staining, of the green hydrophobic treatment, still allowing the stone to retain adequate vapor permeability. The efficacy of the eco-friendly product was analyzed also after a short time (four weeks) of outdoor exposure. Suitable performance and short-term durability of the green hydrophobic coating were found, comparable or even greater than those reported in the current literature for other widespread commercial products, confirming the capability of the product to preserve porous stone surfaces even in absence of solvents in its formulation. The study also allowed to experiment with the “contact sponge” test as an appropriate method for evaluating the water absorption properties of the stone.

Releasing incompatible males drives strong suppression across populations of wild and Wolbachia-carrying Aedes aegypti in Australia

Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the “Debug” Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

The Effects of Low Temperature Carbon Diffusion on Stainless Steel

Stainless steels along with Nickel based alloys are often selected for many applications in corrosive environments. While resistance to corrosion makes them a favorable choice, poor tribological behavior may prevent a broader use of these materials. The Kolsterising® process is a proven method for the surface hardening of these materials by the diffusion of carbon. This paper intends to highlight the improvements typically seen in key mechanical properties including resistance to galling, wear resistance, and fatigue life. Untypically, due to the nature of the process, these properties are generally improved without the usual associated reduction in corrosion resistance. Property improvements will be demonstrated using both new and existing data from Europe and North America.

Comparison of Two Conjunctival Incision Techniques in Strabismus Operations: Analysis of the Patient Population in 2008, 2010 – 2014

Background Until 2010, the Halle university hospital used the limbal approach in strabismus operations to open the conjunctiva, as first described by Harms in 1949. In 2010, this was changed the to a modified radial incision technique, as inspired by the fornix incision of Harms and the “minimally invasive strabismus surgery” (MISS) technique of D. S. Mojon. The indication is the reduction in complications and protection of the conjunctiva. Methods A retrospective analysis was performed of cases between 2008 and March 2014 was performed, including a total of 258 patients. 109 patients were treated with the limbal approach and 149 patients with the radial cut. The following aspects were included for comparison: the medium-term control of the squint angle after three months, intra- and postoperative number of complications, duration of the operations. A survey collected the reasons for not taking part in follow-up checks and the alignment of these patients. To compare binary variables, the chi-square-test was used and to compare average terms the unpaired t test, with a level of significance of 0.05%. Results The results of the postoperative square angles were comparable to both each other as to the literature. The number of complications was kept low in both techniques. The duration of the operations under the radial incision technique was clearly higher. However, throughout the observed years the duration of operations turned out to have decreased. The reasons for not taking part in controls were diverse and the alignment of these patients was high, regardless of the incision technique. Conclusions The limbal approach was a well-proven method to open the conjunctiva. After changing to the radial incision technique, there was never a negative influence on the results of the surgeries or the rate of complications. The duration of the operations was extended. Superiority of the new technique was not shown. It could however be an alternative, as it spares the conjunctiva and permits glaucoma operations.

Setting Thresholds to Define Indifferences and Preferences in PROMETHEE for Life Cycle Sustainability Assessment of European Hydrogen Production

The Life Cycle Sustainability Assessment (LCSA) is a proven method for sustainability assessment. However, the interpretation phase of an LCSA is challenging because many different single results are obtained. Additionally, performing a Multi-Criteria Decision Analysis (MCDA) is one way—not only for LCSA—to gain clarity about how to interpret the results. One common form of MCDAs are outranking methods. For these type of methods it becomes of utmost importance to clarify when results become preferable. Thus, thresholds are commonly used to prevent decisions based on results that are actually indifferent between the analyzed options. In this paper, a new approach is presented to identify and quantify such thresholds for Preference Ranking Organization METHod for Enrichment Evaluation (PROMETHEE) based on uncertainty of Life Cycle Impact Assessment (LCIA) methods. Common thresholds and this new approach are discussed using a case study on finding a preferred location for sustainable industrial hydrogen production, comparing three locations in European countries. The single LCSA results indicated different preferences for the environmental, economic and social assessment. The application of PROMETHEE helped to find a clear solution. The comparison of the newly-specified thresholds based on LCIA uncertainty with default thresholds provided important insights of how to interpret the LCSA results regarding industrial hydrogen production.

A study of grain refinement of AZ91E and Mg-9 wt.% AI alloys using zinc oxide

Grain refinement is a proven method to improve mechanical properties of Mg alloys. In this research, the influence of ZnO on the microstructure of selected magnesium alloys was investigated. For graphite mold casting with an addition of 0.75 wt. % ZnO, the grain size of the AZ91E alloy decreased from 217 μm to 108 μm. For the binary alloy (Mg-9 wt.% Al), the grain size reduced from 288 μm to 93 μm with an addition of 3 wt.% ZnO. No significant fading of ZnO grain refiner was observed for both the alloys. In permanent mold casting process, with an addition of 0.5 wt.% ZnO, the grain size of the AZ91E alloy decreased from 133μm to 79 μm with significant improvements in mechanical properties. Cleavage type fracture was dominant in the base alloy while alloys refined with 0.5 wt.% ZnO showed more quasi-cleavage type fracture.

A study of grain refinement of AZ91E and Mg-9 wt.% AI alloys using zinc oxide

Grain refinement is a proven method to improve mechanical properties of Mg alloys. In this research, the influence of ZnO on the microstructure of selected magnesium alloys was investigated. For graphite mold casting with an addition of 0.75 wt. % ZnO, the grain size of the AZ91E alloy decreased from 217 μm to 108 μm. For the binary alloy (Mg-9 wt.% Al), the grain size reduced from 288 μm to 93 μm with an addition of 3 wt.% ZnO. No significant fading of ZnO grain refiner was observed for both the alloys. In permanent mold casting process, with an addition of 0.5 wt.% ZnO, the grain size of the AZ91E alloy decreased from 133μm to 79 μm with significant improvements in mechanical properties. Cleavage type fracture was dominant in the base alloy while alloys refined with 0.5 wt.% ZnO showed more quasi-cleavage type fracture.

Optimization Algorithm to Sequence the Management Processes in Information Technology Departments

The most important standard in technology services management is the Information Technology Infrastructure Library (ITIL). The literature review developed shows that one of the most important questions to answer is finding the sequence of processes to be implemented, mainly in small companies with few resources. The purpose of this paper is to show a methodology that defines an optimal specific sequence of processes for each small company depending on internal and external parameters. The main contribution of this paper is a proven methodology to obtain a particular sequence of ITIL processes specifically adapted to each company, based on a mathematical and statistical model that uses data from a web survey. Its application generates an optimal sequence of ITIL processes. The methodology has been applied with successful results in a real case, and it shows specific benefits over the previous approaches. The main learning objective of this research is a proven method to obtain an optimal sequence of processes for the implementation of ITIL in small companies. Finally, some future works are presented.