Can A Low Cost Sensing System Be Exploited For High Precision Machining

Abstract The aim of the present study is the assessment of the integration of a low cost optical measurement device into a high-precision machine tool for micro manufacturing applications. The measurement system can be effectively integrated into the working volume of different types of machines allowing both tool and workpiece measurements and avoiding its disassembly from the machine stage for off-line measurements and, consequently, reference losses. The fast measurements of tool and workpiece during the machining contribute to increase the accuracy and reduce the overall machining-measurement iterations. The assessment is achieved by a test case where a low cost USB microscope is applied to a micro-EDM machine. The low cost device has been applied for tool electrode measurements and tool wear evaluation after an accuracy enhanced calibration procedure and high performance image processing algorithms, which effectively reduce the lack of the hardware performance. The measurement performance gives a feedback on the deviations of the machined features from nominal geometry and allows their compensations by an adequate machining strategy

Towards the Automated Coverlay Assembly in FPCB Manufacturing: Concept and Preliminary Tests

AbstractIn modern electronics, flexible and rigid-flex PCBs are largely used due to their intrinsic versatility and performance, allowing to increase the available volume, or enabling connection between unconstrained components. Rigid-flex PCBs consists of rigid board portions with flexible interconnections and are commonly used in a wide variety of industrial applications. However, the assembly process of these devices still has some bottlenecks. Specifically, they require the application of cover layers (namely, coverlays), to provide insulation and protection of the flexible circuits. Due to the variability in planar shape and dimensions, the coverlay application is still performed manually, requiring troublesome manipulation steps and resulting in undetermined time-cycle and precision.This paper aims at the improvement of the industrial process currently performed, by proposing an approach for the automation of Kapton coverlay manipulation and application. Since these products are commercially provided as a film with a protective layer to be removed, the peeling issue is addressed, representing a challenging step of the automated process; the results of a systematic series of tests, performed in order to validate the peeling strategy, are reported in the paper. The overall assembly strategy relies on the development of a customized multi-hole vacuum gripper, whose concept is presented and contextualized in the proposed assembly process by outlining a suitable workcell architecture

Bio-Inspired Dielectric Resonator Antenna for Wideband Sub-6 GHz Range

Through the years, inspiration from nature has taken the lead for technological development and improvement. This concept firmly applies to the design of the antennas, whose performances receive a relevant boost due to the implementation of bio-inspired geometries. In particular, this idea holds in the present scenario, where antennas working in the higher frequency range (5G and mm-wave), require wide bandwidth and high gain; nonetheless, ease of fabrication and rapid production still have their importance. To this aim, polymer-based 3D antennas, such as Dielectric Resonator Antennas (DRAs) have been considered as suitable for fulfilling antenna performance and fabrication requirements. Differently from numerous works related to planar-metal-based antenna development, bio-inspired DRAs for 5G and mm-wave applications are at their beginning. In this scenario, the present paper proposes the analysis and optimization of a bio-inspired Spiral shell DRA (SsDRA) implemented by means of Gielis' superformula, with the goal of boosting the antenna bandwidth. The optimized SsDRA geometrical parameters were also determined and discussed based on its fabrication feasibility exploiting Additive Manufacturing technologies. The results proved that the SsDRA provides relevant bandwidth, about 2 GHz wide, and satisfactory gain (3.7 dBi and 5 dBi, respectively) at two different frequencies, 3.5 GHz and 5.5 GHz

3D Printed Micro-Cells for Phase Control in 5G mmWave Applications

In this work, the design, fabrication and characterization of micro-air-channel-based unit cells aimed at phase control exploitable in 5G-mmwave applications are reported. The basic unit cell consisted of rectangular dielectric blocks (RDB) placed onto a thin substrate, realized by means of a resin polymer. The RDB effective relative permittivity was changed by tuning specific design parameters and infill density percentage (ID%), that was engineered through the introduction of a number of uniformly distributed micro-air channels. The reflected phase variation was numerically quantified in terms of frequency range and ID%, thus proving that a controlled phase variation can be accomplished depending on air-channel number. The prototypes were fabricated by means of the micro-inverted Stereolithography (SLA). In order to assess the accuracy of the SLA technology on the dimensions imposed by the high aspect ratio of the structures, larger unit cells operating in the X band were first fabricated. The acquired technological know-how has been subsequently exploited to fabricate smaller unit cells operating at mmwave. Geometrical characterizations of the prototypes, performed via a visual system setup, put in evidence the technological challenges, especially faced to realize open micro-air channels. In particular, as smaller micro-channel were actually obtained for some samples, a consequent increase of the actual ID% and effective relative permittivity values was experienced by the related unit cells. Nonetheless, the experimental results performed on the fabricated prototypes in the X band and mmwave range were in good agreement with the numerical ones, confirming the phase variation vs. ID% trends of the simulated unit cell arrays

Design and Manufacturing of Super-Shaped Dielectric Resonator Antennas for 5G Applications Using Stereolithography

In this work, the inverted micro-Stereolithography (SLA) is used to show the potential of such additive manufacturing (AM) technology at prototyping super-shaped dielectric resonator antennas (S-DRAs) rapidly and accurately. The S-DRAs, which exhibit 3D complex geometries, were designed to operate at 3.5 GHz, suitable for the assessment of 5G communications in the mid band. Initially, a cross-starred-shaped S-DRA was designed and manufactured via the inverted micro-SLA by means of a photopolymer resin as material. As no information about the used material was available from literature and supplier, the dielectric properties of the photopolymer resin were characterized. Moreover, in the view of challenging further the SLA capability, several prototypes, based on the cross star shaped geometry but exhibiting a twist of variable angles along the longitudinal axis, were fabricated and tested. In order to compare the antennas performance in relation to the material volume and sizes, rectangular and cylindrical DRAs were also realized using same material and technology. Scattering parameter S11, gain, bandwidth (BW), efficiency and co- and cross-polarization of all antennas were measured. The experimental results showed that twisted S-DRAs exhibit same performance of the basic cross-starred-shaped antenna, due to the invariance to symmetry of the basic Gielis geometry. The measured gain is about 2.5 dB over a range of 1 GHz in the frequency range of interest; the BW measured for all S-DRAs is about 10%, whereas the efficiency is about 80% at 3.5 GHz. Finally, better performance in terms of bandwidth is shown by the S-DRAs, considering their dramatic volume reduction (~85%) compared to classic rectangular and cylindrical DRAs and other DRA examples already reported in the state of the art

Safety, Immunogenicity and Dose Ranging of a New Vi-CRM197 Conjugate Vaccine against Typhoid Fever: Randomized Clinical Testing in Healthy Adults

Typhoid fever causes more than 21 million cases of disease and 200,000 deaths yearly worldwide, with more than 90% of the disease burden being reported from Asia. Epidemiological data show high disease incidence in young children and suggest that immunization programs should target children below two years of age: this is not possible with available vaccines. The Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM₁₉₇) for infant vaccination concomitantly with EPI vaccines, either starting at 6 weeks with DTP or at 9 months with measles vaccine. We report the results from a Phase 1 and a Phase 2 dose ranging trial with Vi-CRM₁₉₇ in European adults.Following randomized blinded comparison of single vaccination with either Vi-CRM₁₉₇ or licensed polysaccharide vaccines (both containing 25·0 µg of Vi antigen), a randomised observer blinded dose ranging trial was performed in the same center to compare three concentrations of Vi-CRM₁₉₇ (1·25 µg, 5·0 µg and 12·5 µg of Vi antigen) with the polysaccharide vaccine.All vaccines were well tolerated. Compared to the polysaccharide vaccine, Vi-CRM₁₉₇ induced a higher incidence of mild to moderate short lasting local pain. All Vi-CRM₁₉₇ formulations induced higher Vi antibody levels compared to licensed control, with clear dose response relationship.Vi-CRM₁₉₇ did not elicit safety concerns, was highly immunogenic and is therefore suitable for further clinical testing in endemic populations of South Asia.ClinicalTrials.gov NCT01123941 NCT01193907

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe