Search

In this paper, the recently proposed structural optimization strategy, the Galilei-Optimization (GO), is adapted for improving the toughness response of a holed two-dimensional lattice system made of a network of micro-beams whose geometrical arrangement was prescribed. By taking advantage of the possibility of minimizing stress gradients and stress peaks around the hole via GO, we redesigned the cross sections of the lattice beam elements, equalizing the stresses over the entire domain. Consequently, the resulting optimized microstructure highlighted a significant enhancement of the overall toughness due to a drastic decrease of the stress concentration factor in the hole proximity, preserving the initial stiffness and lowering the total overall weight. To validate the robustness of the procedure and the numerical Finite Element outcomes, two non-optimized and optimized structures were actually built up through 3D printing and tested in the laboratory under the same boundary conditions used for the simulations. This evidence confirmed the effectiveness of the proposed method in obtaining optimized beam-like plates with high toughness, which could pave the way for designing new light materials with extreme mechanical performance well beyond the sole stiffness and strength.

Nowadays, engine experimental research represents a very expensive field within the automotive industry, but it remains fundamental for engine and vehicle development. The present work aims to investigate a novel approach for engine control system calibration, by adopting machine learning techniques to model physical parameters of the engine starting from experimental data measured at the test bench. The main goal is to create a methodology which accelerates the calibration process without losing accuracy. A model that estimates air mass flow is created by adopting either a tree ensemble model or an artificial neural network trained on a small dataset, which was previously acquired at the test bench using a random calibration of the volumetric efficiency map. The model’s performance is first validated on a larger, random dataset. Then, the volumetric efficiency calculated from the air mass flow model estimation is used to calibrate the transfer function of the Engine Control Unit. Finally, the sensitivity of the model error correlated with the number of data points acquired is used in order to determine the best practice for a Design Of Experiment, which minimizes data acquisition. The methodology proposed can lead to reduced time and costs of the whole calibration process of the engine, without losing accuracy. The analysis was conducted on the entire vehicle, which is crucial for drivability, especially in motorcycles since they are highly sensitive to air-to-fuel ratio adjustments. This work demonstrates that machine learning models can be adopted for the fine-tuning of the calibration process, which is normally performed manually.

ABSTRACTThis study presents an original mapping of hydrological karst features of the Matese massif (southern Italy), whose relevance is given by large basal springs supplying millions of people and the hydroelectric exploitation of the major endorheic areas. We mapped dolines and endorheic areas from 1- and 5-meter Digital Elevation Models (DEM) using Geographic Information System (GIS) tools and techniques. Instead, ponors, caves, and karst springs were mapped mainly based on cartographic and literature analyses. We identified 321 endorheic areas occupying 31% of the massif area and 489 dolines, distinguished in (i) solution (N = 433) and collapse dolines (N = 56), the latter located in the discharge zones of the massif and connected to ascendant flows of CO2- and H2S-rich groundwater. The map shows the hydrological features of a karst massif from a more detailed and new perspective, and it can be helpful in water management, groundwater resource protection, environmental safeguarding, and ecological development.

Abstract The rechallenge strategy is based on the concept that a subset of patients with RAS wild‐type (WT) metastatic colorectal cancer (mCRC) could still benefit of epidermal growth factor receptor (EGFR) inhibition, after progression to an anti‐EGFR based‐therapy. We performed a pooled analysis of two‐phase II prospective trials to determine the role of rechallenge in third‐line mCRC patients with RAS/BRAF WT baseline circulating tumor DNA (ctDNA). Individual data of 33 and 13 patients from CAVE and CRICKET trials that received as third‐line therapy cetuximab rechallenge were collected. Overall survival (OS), Progression‐free survival (PFS), Overall response rate (ORR), Stable disease (SD) >6 months were calculated. Adverse events were reported. For the whole 46 patient population, median PFS (mPFS) was 3.9 months (95% Confidence Interval, CI 3.0–4.9) with median OS (mOS) of 16.9 months (95% CI 11.7–22.1). For CRICKET patients, mPFS was 3.9 months (95% CI 1.7–6.2); mOS was 13.1 months (95% CI 7.3–18.9) with OS rates at 12, 18, and 24 months of 62%, 23%, and 0%, respectively. For CAVE patients, mPFS was 4.1 months (95% CI 3.0–5.2); mOS was 18.6 months (95% CI 11.7–25.4) with OS rates at 12, 18, 24 months of 61%, 52%, 21%, respectively. Skin rash was more frequently reported in CAVE trial (87.9% vs. 30.8%; p = 0.001), whereas a increased incidence of hematological toxicities was observed in CRICKET trial (53.8%% vs. 12.1%; p = 0.003). Third‐line cetuximab rechallenge in combination with either irinotecan or avelumab in RAS/BRAF WT ctDNA mCRC patients represents a promising therapy.

The LHC heavy-ion program with ^{208}Pb^{82+} beams will benefit from a significant increase of the beam intensity when entering its high-luminosity era in Run 3 (2023). The stored energy is expected to surpass 20 MJ per beam. The LHC is equipped with a betatron collimation system, which intercepts the transverse beam halo and protects sensitive equipment such as superconducting magnets against beam losses. However, nuclear fragmentation and electromagnetic dissociation of ^{208}Pb^{82+} ions in collimators generates a flux of secondary fragments, which are lost in downstream dispersion suppressor and arc cells. These secondary ions may pose a performance limitation in upcoming runs since they can induce magnet quenches. In order to mitigate this risk, an alternative collimation technique, relying on bent crystals as primary collimators, will be used in forthcoming heavy-ion runs. In this paper, we study the power deposition in superconducting magnets by means of tracking and fluka shower simulations, comparing the standard collimation system against the crystal-based one. In order to quantify the predictive ability of the simulation model, we present absolute benchmarks against beam loss monitor measurements from the 2018 ^{208}Pb^{82+} run at 6.37 ZTeV. The benchmarks cover several hundred meters of beamline, from the primary collimators to the first arc cells. Based on these studies, we provide a detailed analysis of ion fragmentation and leakage to the cold magnets and quantify the expected quench margin in future ^{208}Pb^{82+} runs.

The aim of the present study was to investigate the culturable microflora of pool frogs (Pelophylax lessonae) and their belonging aquatic environment. A total of 60 samples (56 frog cutaneous swabs, 4 water samples) were inoculated onto different selective and differential agar plates to isolate Gram-positive and Gram-negative bacteria or yeasts. Microbial investigation of the water hosting frogs was also performed. Isolates were identified by API system and their antibiotic resistance profiles were evaluated by disk diffusion method on Mueller Hinton agar plates. Aeromonas hydrophila and En-terococcus durans were detected in almost all collected samples. Many of the bacterial isolates showed multidrug-resistant profiles. Importantly, this study highlights that skin frog microbiota is correlated to the belonging environment, and, moreover, some isolated bacterial strains resulted to be of interest in animal and public health, since the park was frequented by visitors of all ages.

Reconstruction after excision of infiltrating basal cell carcinomas (BCCs) of the upper pole of the ear can be achieved with different techniques. The concept of spare-part surgery, which allows the surgeon to perform primary reconstruction of a defect without harvesting tissue from the adjacent areas, has been applied to the ear anatomy. We describe our experience with the use of a fillet flap from the residual external ear in two patients out of a series of six, undergoing reconstruction of ear defects after infiltrating BCC resection between January 2011 and December 2014. Reconstruction with the fillet of pinna flap was proven to be an easy surgical technique with good functional and cosmetic outcomes. Our technique, not previously reported, enhances the versatility of ear reconstruction.

Total Hip Arthroplasty has been one of the most successful surgical procedure in terms of patient outcomes and satisfaction. However, due to increase in life expectancy and the related incidence of age-dependent bone diseases, a growing number of cases of intra-operative fractures lead to revision surgery with high rates of morbidity and mortality. Surgeons choose the type of the implant, either cemented or cementless prosthesis, on the basis of the age, the quality of the bone and the general medical conditions of the patients. Generally, no quantitative measures are available to assess the intra-operative fracture risk. Consequently, the decision-making process is mainly based on surgical operators’ expertise and qualitative information obtained from imaging. Motivated by this scenario, we here propose a mechanical-supported strategy to assist surgeons in their decisions, by giving intelligible maps of the risk fracture which take into account the interplay between the actual mechanical strength distribution inside the bone tissue and its response to the forces exerted by the implant. In the presented study, we produce charts and patient-specific synthetic “traffic-light” indicators of fracture risk, by making use of ad hoc analytical solutions to predict the stress levels in the bone by means of Computed Tomography-based mechanical and geometrical parameters of the patient. We felt that if implemented in a friendly software or proposed as an app, the strategy could constitute a practical tool to help the medical decision-making process, in particular with respect to the choice of adopting cemented or cementless implant.

The data produced at the particle physics experiments at the Large Hadron Collider (LHC) contain not only the signals from the collisions, but also a background component from proton losses around the accelerator. Understanding, identifying and possibly mitigating this machine-induced background is essential for an efficient data taking, especially for some new physics searches. Among the sources of background are hadronic and electromagnetic showers from proton losses on nearby collimators due to beam-halo cleaning. In this article, the first dedicated LHC measurements of this type of background are presented. Controlled losses of a low-intensity beam on collimators were induced, while monitoring the backgrounds in the ATLAS detector. The results show a clear correlation between the experimental backgrounds and the setting of the tertiary collimators (TCTs). Furthermore, the results are used to show that during normal LHC physics operation the beam halo contributes to the total beam-induced background at the level of a percent or less. A second measurement, where the collimator positions are tightened during physics operation, confirms this finding by setting a limit of about 10% to the contribution from all losses on the TCTs, i.e. the sum of beam halo and elastic beam-gas scattering around the ring. Dedicated simulations of the halo-related background are presented and good agreement with data is demonstrated. These simulations provide information about features that are not experimentally accessible, like correlations between backgrounds and the distributions of proton impacts on the collimators. The results provide vital information about the dependence between background and collimator settings, which is of central importance when optimizing the LHC optics for maximum peak luminosity.

In vitro embryo production (IVEP) is largely applied world wide to animal breeding. One of the principal steps of the IVEP is represented by embryo culture (Khurana and Niemann., 2000). In the past, embryos were grown in co-culture systems with other cells such as oviductal epithelial cells, cumulus cells, Buffalo rat liver (BRL) and VERO cells (Duszewska et al., 2000). These cells are able to supply the nutrients for embryo development by their replication and metabolism. Nevertheless, the metabolic activity of these cells is also responsible of an early lowering of pH in the culture medium: that needs to be changed every two days. Furthermore, with this culture system it is impossible to standardize all the procedure: in fact the result is dependent from several variables, as the quality of the cells and their concentration in co-culture. The use of defined culture media is necessary to acquire a better comprehension of metabolism and biochemical requirements for IVEP........

Solid biomass is often mixed with coal for cofiring in power plants to reduce greenhouse gases emissions. The resulting powder mixtures can give rise to handling and feeding problems due to the occurrence of intermittent flow or blockage. In this paper the flow properties of mixtures of a coal-petcoke powder and two types of biomass materials, dried olive husk (OH) and grape seed meal (GSM), were studied. The most significant effects on the cohesive properties of some powder mixtures were found for low biomass content mixtures due to their higher fraction of fine particles.

Although diffusional flow creep is often considered out of practical engineering applications, the need for a model capable to account for the resulting action of both diffusional and dislocation type creep is justified by the increasing demands of reliable creep design for very long lives (exceeding lOO.OOOh), high stress-low temperatures and high temperature-low stress regimes. In this paper, a creep model formulation, in which the change of the creep mechanism has been accounted for through an explicit dependence of the creep exponent n on stress and temperature, has been proposed. An application example of the proposed approach to high purity aluminum is given.