Parametric virtual concept design of heavy machinery: a case study application

Virtual prototyping enables the validation and optimization of machinery equivalent to physical testing, saving time and costs in the product development, especially in case of heavy machines with complex motions. However, virtual prototyping is usually deployed only at the end of the design process, when product architecture is already developed. The present paper discusses the introduction of virtual prototypes since conceptual design stage as Virtual Concepts in which coarse models of machinery design variants are simulated obtaining useful information, sometimes fundamental to support best design choices. Virtual Concept modeling and preliminary validation and its later integration to a Virtual Prototype are expressly investigated using Multi Body Dynamics software. A verification case study on a large vibrating screen demonstrates that dynamic Virtual Concepts enable easier and effective evaluations on the design variants and increase the design process predictability

The Systematic Design of Industrial Products through Design Archetypes: An Application on Mechanical Transmissions

Engineering design is a knowledge intensive activity for both new and mature technical systems, such as mechanical transmissions. However, design knowledge is often transferred with conservative and unstructured approaches, although knowledge management would be of the utmost importance for modern industries. In this work, we introduce a design tool, called design archetype, for collecting and managing knowledge in systematic design processes. The design archetype addresses input design requirements for different design concepts, therefore, improving awareness of the design process by interactively modifying the design solution due to different input requirements. Finally, the design archetype updates the parameters of a first embodiment computer-aided design model of the concept. A method for the development of design archetypes is presented and applied to two case studies of mechanical transmission subassemblies. The results demonstrate the effectiveness of a systematic design method based on design archetypes stored in the company database

Drone-Borne Ground-Penetrating Radar for Snow Cover Mapping

Ground-penetrating radar (GPR) is one of the most commonly used instruments to map the Snow Water Equivalent (SWE) in mountainous regions. However, some areas may be difficult or dangerous to access; besides, some surveys can be quite time-consuming. We test a new system to fulfill the need to speed up the acquisition process for the analysis of the SWE and to access remote or dangerous areas. A GPR antenna (900 MHz) is mounted on a drone prototype designed to carry heavy instruments, fly safely at high altitudes, and avoid interference of the GPR signal. A survey of two test sites of the Alpine region during winter 2020-2021 is presented, to check the prototype performance for mapping the snow thickness at the catchment scale. We process the data according to a standard flow-chart of radar processing and we pick both the travel times of the air-snow interface and the snow-ground interface to compute the travel time difference and to estimate the snow depth. The calibration of the radar snow depth is performed by comparing the radar travel times with snow depth measurements at preselected stations. The main results show fairly good reliability and performance in terms of data quality, accuracy, and spatial resolution in snow depth monitoring. We tested the device in the condition of low snow density (<200 kg/m(3)) and this limits the detectability of the air-snow interface. This is mainly caused by low values of the electrical permittivity of the dry soft snow, providing a weak reflectivity of the snow surface. To overcome this critical aspect, we use the data of the rangefinder to properly detect the travel time of the snow-air interface. This sensor is already installed in our prototype and in most commercial drones for flight purposes. Based on our experience with the prototype, various improvement strategies and limitations of drone-borne GPR acquisition are discussed. In conclusion, the drone technology is found to be ready to support GPR-based snow depth mapping applications at high altitudes, provided that the operators acquire adequate knowledge of the devices, in order to effectively build, tune, use and maintain a reliable acquisition system

Geophysical–geotechnical methodology for assessing the spatial distribution of glacio‐lacustrine sediments: The case history of Lake Seracchi

Proglacial lakes are distinctive features of deglaciated landscapes and often act as sediment sinks, collecting solid material from subglacial erosion or washout of degla- ciated areas. The solid transport flow, strongly linked to the glaciers and periglacial landforms, may rise due to the rapid changes driven by climate warming, causing deep transformations in the basin hydrology, and even the appearance or disappear- ance of lakes at a decadal timescale. The goal of this study was to present a geophysical–geotechnical approach that inte- grates several techniques, to quantify the sediment distribution in a proglacial lake. A geophysical survey is performed with ground-penetrating radar (GPR) installed on a boat, whereas a time-domain reflectometer (TDR) measures the electrical conductiv- ity and permittivity of the lakebed sediments. Unperturbed samples are collected and analyzed to measure the main geotechnical properties of the sediment: grain-size dis- tribution, plastic limit, and liquid limit. Such properties support the interpretation of the GPR data and the detection of spatial variations of the sediment facies. To validate the proposed methodology, field tests were carried out at Lake Seracchi, the largest lake of the Rutor glacier, Italian Alps. It formed around 1880 because of the recent glacier shrinkage, as chronicled by valuable historical documents. Its greyish waters carry a significant amount of suspended sediment recognized as gla- cial flour, which gradually accumulates on the bottom of the lake. The obtained bathymetry and sediment thickness maps of Lake Seracchi show the strength of the approach: from only a few manual samples, it is possible to extrapo- late the geotechnical properties of interest, such as friction angle or hydraulic con- ductivity, to wider areas, surveyed by the geophysical techniques. This is achieved by investigating the spatial distribution of key geophysical properties linked to the geo- technical properties of interest

A Minimal Touch Approach for Optimizing Energy Efficiency inPick-and-Place Manipulators

The interest in novel engineering methods andtools for optimizing the energy consumption in robotic systemsis currently increasing. In particular, from an industry pointof view, it is desirable to develop energy saving strategiesapplicable also to established manufacturing systems, beingliable of small possibilities for adjustments.Within this scenario,an engineering method is reported for reducing the totalenergy consumption of pick-and-place manipulators for givenend-effector trajectory. Firstly, an electromechanical model ofparallel/serial manipulators is derived. Then, an energy-optimaltrajectory is calculated, by means of time scaling, starting froma pre-scheduled trajectory performed at maximum speed (i.e.compatible with actuators limitations). A simulation case studyfinally shows the effectiveness of the proposed procedure

Integrated use of chemical and geophysical monitoring to study the diesel oil biodegradation in microcosms with different operative conditions

This study aimed to monitor the aerobic bioremediation of diesel oil-contaminated soil by measuring: a) the CO2 production; 2) the fluorescein production; 3) the residual diesel oil concentration.Moreover, the complex dielectric permittivity was monitored through an open-ended coaxial cable. Several microcosms were prepared, changing the water content (u%= 8–15% by weight), the carbon to nitrogen ratio (C/N = 20–450), and the soil amount (200 and 800 g of dry soil). The cumulative CO2 and fluorescein production showed similar trends, but different values since these two parameters reflect different features of the biological process occurring within each microcosm. The diesel oil removal efficiency depended on the microcosm characteristics. After 84 days, in the microcosms with 200 g of dry soil, the highest removal efficiency was achieved with a water content of 8% by weight and C/N = 120, while in themicrocosms with 800 g of dry soil the best result was achieved with the water content equal to 12%by weight and C/N = 100. In the tested soil, the bioremediation process is efficient if the water content is in the range 8–12% by weight, and C/N is in the range 100–180; under these operative conditions, the diesel oil removal efficiency was about 65–70¯ter 84 days. The dielectric permittivity wasmonitored in microcosms with 200 g of dry soil. The open-ended coaxial cable detected significant variations of both the real and the imaginary component of the dielectric permittivity during the bioremediation process, due to the physical and chemical changes that occurred within the microcosms

Selective Removal of Diesel Oil Hydrocarbons in Aerobic Bioremediation

In soil bioremediation, the main target is the removal of pollutants to the maximum extent. Careful monitoring of pollution concentration provides information about the process efficacy and removal efficiency. Moreover, a detailed analysis of residual pollution composition provides a detailed picture of single compound removal or presence, especially of interest when pollution is constituted by a mixture of chemical species. This paper shows the first results of a study on the speciation of diesel oil compound removal from soils by aerobic remediation. The experimental study was carried out in a microcosm using indigenous microorganisms and adopting the biostimulation strategy with a mineral salt medium for bacteria. The microcosm contained 200 g of dry soil and 14 g of diesel oil with a carbon to nitrogen ratio (C/N) equal to 180 and water content (u%) equal to 12% by mass. The residual pollution concentration in soil was monitored for 138 days to evaluate both the overall removal efficiency and that for the main groups of hydrocarbons. The results showed that the pollution composition changed during the test because of the different rate of metabolization for the single compounds: the overall removal efficiency was about 65%, and that of different hydrocarbon clusters was between 53% and 88%. The monitoring data also allowed the kinetic study of the degradation process, which was better modeled by a second-order kinetic model than by a first-order one. These findings were confirmed by analyzing other microcosms with different operative conditions (C/N = 120, 180 and u% = 8%, 12%, 15% by mass). The proposed methodology may be useful for the evaluation of compliance to concentration limits imposed by law

Increasing the Energy Efficiency of Multi-robot Production Lines in the Automotive Industry

This paper quantitatively reports bout potential energy savings on robotic assembly lines for the automotive industry. The key aspect of the proposed approach is that both cell production rate and robot hardware limitations are consideredasstrictconstraints,sothatnoplantrevisionis needed. The methodology relies on: a)calculationofenergy- optimal trajectories, by means of time scaling, concerning the robots’ motion from the last process point to the home positions; b)reduction o f the energy consumption vi aearlier release of the actuator brake whentherobotsarekeptstationary. Simulation results arepresented,whicharebasedontheproductiontiming characteristicsmeasuredonarealplant

Time-Domain Reflectometry (TDR) monitoring at a lab scale of aerobic biological processes in a soil contaminated by diesel oil

This study aims to monitor the biological processes ongoing in a hydrocarbon polluted soil. The experiments were carried out at a laboratory scale by measuring the evolution of its geophysical electromagnetic parameters. Time-domain reflectometry (TDR) probes were used to measure dielectric permittivity and electrical conductivity in columns of sandy soil artificially contaminated with diesel oil (Voil/Vtot = 0.19). To provide aerobic conditions suitable for the growth of microorganisms, they were hydrated with Mineral Salt Medium for Bacteria. One mesocosm was aerated by injecting air from the bottom of the column, while the other had only natural aeration due to diffusion of air through the soil itself. The monitoring lasted 105 days. Geophysical measurements were supported by microbiological, gas chromatographic analyses, and scanning electron microscope (SEM) images. Air injection heavily influenced the TDR monitoring, probably due to the generation of air bubbles around the probe that interfered with the probe–soil coupling. Therefore, the measurement accuracy of geophysical properties was dramatically reduced in the aerated system, although biological analyses showed that aeration strongly supports microbial activity. In the non-aerated system, a slight (2%) linear decrease of dielectric permittivity was observed over time. Meanwhile, the electrical conductivity initially decreased, then increased from day 20 to day 45, then decreased again by about 30%. We compared these results with other researches in recent literature to explain the complex biological phenomena that can induce variations in electrical parameters in a contaminated soil matrix, from salt depletion to pore clogging