3,420 research outputs found
Design and test of a prototype scale ejector wing
A two dimensional momentum integral analysis was used to examine the effect of changing inlet area ratio, diffuser area ratio, and the ratio of ejector length to width. A relatively wide range of these parameters was considered. It was found that for constant inlet area ratio the augmentation increases with the ejector length, and for constant length: width ratio the augmentation increases with inlet area ratio. Scale model tests were used to verify these trends and to examine th effect of aspect ratio. On the basis of these results, an ejector configuration was selected for fabrication and testing at a scale representative of an ejector wing aircraft. The test ejector was powered by a Pratt-Whitney F401 engine developing approximately 12,000 pounds of thrust. The results of preliminary tests indicate that the ejector develops a thrust augmentation ratio better than 1.65
Multi-stage Strategic Approach in Spatial Innovation: How Innovation District Matter?
In the 21st century globalised economy, innovation is a crucial factor within strategies targeted at growing and sustaining competitiveness of regions and cities. Accordingly, the creation of knowledge process, along with sharing and commercialisation, became an effective response to the pressures generated by globalisation in order to increase the competitive advantage. The emerging trend of innovation-led urban planning initiatives provides strong evidence of how cities are implementing strategies to promote innovation mainstreaming. Hence, these innovation-oriented policies, which are targeted at reshaping cities, are currently translated in the creation of innovation districts. This paper aims at identifying the actors who foster the innovation process at urban level, and analysing their influence throughout the innovation district life cycle. Firstly, the authors assess the role played by public and private sector in the different stages of innovation district development, by adapting the Urban Land Institute conceptual framework in the Innovation Life Cycle District Assessment. Secondly, empirical research works are defined in order to test the ILCDA. The Boston Innovation District and the IDEA District are the two case studies under investigation, by pointing out the policies and planning initiatives undertaken in the Seaport area of Boston and in Downtown San Diego, respectively. Findings from this research highlight the level of public private partnership effectiveness in supporting the development of innovation districts. Useful lessons can be drawn in encouraging planners and policy-makers towards undertaking combined actions at the different stages of the development process
A room-temperature alternating current susceptometer - Data analysis, calibration, and test
An AC susceptometer operating in the range of 10 Hz to 100 kHz and at room
temperature is designed, built, calibrated and used to characterize the
magnetic behaviour of coated magnetic nanoparticles. Other weakly magnetic
materials (in amounts of some millilitres) can be analyzed as well. The setup
makes use of a DAQ-based acquisition system in order to determine the amplitude
and the phase of the sample magnetization as a function of the frequency of the
driving magnetic field, which is powered by a digital waveform generator. A
specific acquisition strategy makes the response directly proportional to the
sample susceptibility, taking advantage of the differential nature of the coil
assembly. A calibration method based on conductive samples is developed.Comment: 8 pages, 7 figures, 19 ref
Acoustic Characterization and Quality Assessment of Cremona’s Ponchielli Theater
The Ponchielli theater of Cremona was built in 1808 after a fire destroyed the old wooden structure. The interior, the architecture and the shape of the plan layout are reminiscent of the Teatro alla Scala, Milan, a masterpiece by the architect Piermarini, albeit on a smaller scale. The four orders of balconies crowned by the top gallery are typical features of a 19th Century Italian Opera theater. Acoustic measurements have been undertaken across the stalls and in some selected boxes according to ISO 3382. The main acoustic parameters resulting from the measurements have been used for the acoustic calibration of a 3D model representing the Ponchielli theater. The calibration has been used to compare different scenarios involving the acoustic response of the main hall at 50% and 100% occupancy. The outcomes indicate that no significant change can be detected when the seats are provided with robust upholstery, which can be considered a positive result, especially for the actors who are not forced to change their effort between rehearsal and live performance. In order to contextualize the measured values in relation to the optimal ones, a comparison with other Italian Opera theaters provided with similar architectural characteristics has been carried out. Overall, the findings indicate that the acoustics of the Ponchielli theater are suitable for both music and speech in line with the other selected theaters, as these places were mainly created for multifunctional purposes in the 19th Century
The Only Architectural Testimony of an 18th Century Italian Gordonia-Style Miniature Theatre: An Acoustic Survey of the Monte Castello di Vibio Theatre
The acoustic characteristics and spatial features of the world’s only surviving Italianate Gordonia-style miniature theatre, one of the smallest theatres in the world, have inspired the author to analyse the acoustic behaviour of the Monte Castello di Vibio theatre, also called “Teatro della Concordia”. In this paper, the geometric and architectural features of this historical and unique performing art space were first reproduced, considering that these features are essential factors affecting acoustic characteristics. Subsequently, the acoustic measurements were taken throughout the stall and inside some selected boxes, and their main parameters were acoustically characterised according to ISO 3382-1. Lastly, the main acoustic parameters of the Monte Castello di Vibio theatre were compared to those of the 1763 theatre in Bologna, which is also a miniature theatre of similar size. The aim is to explore the main influences on the acoustic parameters of miniature theatres, and the results show that the plan layout of the theatre and interior decoration are the main factors influencing the acoustic characteristics rather than volume. Preserving the acoustic features of this unique heritage building is also seen as one of the goals of this paper
Bioelectronic technologies and artificial intelligence for medical diagnosis and healthcare
The application of electronic findings to biology and medicine has significantly impacted health and wellbeing. Recent technology advances have allowed the development of new systems that can provide diagnostic information on portable point-of-devices or smartphones. The decreasing size of electronics technologies down to the atomic scale and the advances in system, cell, and molecular biology have the potential to increase the quality and reduce the costs of healthcare.
Clinicians have pervasive access to new data from complex sensors; imaging tools; and a multitude of other sources, including personal health e-records and smart environments. Humans are from being able to process this unprecedented volume of available data without advanced tools. Artificial intelligence (AI) can help clinicians to identify patterns from this huge amount of data to inform better choices for patients.
In this Special Issue, some original research papers focusing on recent advances have been collected, covering novel theories, innovative methods, and meaningful applications that could potentially lead to significant advances in the field
A QR based approach for the nonlinear eigenvalue problem
We describe a fast and numerically robust approach based on the structured QR eigenvalue algorithm for computing approximations of the eigenvalues of a holomorphic matrix-valued function inside the unit circle. Numerical experiments confirm the effectiveness of the proposed method
Postoperative pain and surgical time comparison using piezoelectric or conventional implant site preparation systems
Since its introduction, piezoelectric bone surgery has established an important role in oral surgery and dental implantology. Piezoelectric surgery is efficient at preparing implant site osteotomies due to its selective cut, micro-streaming and cavitational effects, which preserve and maintain the soft tissue. Several advantages have been outlined in patient\u2019s symptoms, both in terms of improved intraoperative comfort and postoperative course. The aim of this study was to compare implant insertion procedures using piezoelectric surgery or conventional drilling. Intra- and postoperative pain, implant site preparation time and learning curve were evaluated. Methods: A total of 13 (7 women/6 men, aged between 45 and 75 years) partially edentulous patients were rehabilitated with 40 titanium implants (n=20). Implant therapy consisted in the inclusion of at least two conical implants between 3.8 and 4.5 mm diameter with a maximum torque of 35 Ncm in randomised bilateral edentulous areas. First sites were prepared with piezodevice (test sites) and the contralateral ones with conventional drilling (control sites). Surgery was always performed by the same operator. Implant site preparation timing was measured from flap elevation until implant inclusion. Patients recorded their subjective intraoperative and postoperative pain daily for 7 days and at 15th day after surgery using a Visual Analog Scale (VAS). Results: Patients treated with piezoelectric technique presented a lower VAS, minor swelling and less recovery time compared to the conventional technique. No operative complications were reported and the implant survival rate at 1 year was 100% for both the techniques. VAS significant differences were found for the test sites as intraoperative symptoms (p = 0.009), after 1 day (p = 0.010), 2 days (p = 0.016), 3 days (p = 0.017), 5 days (p = 0.015), 6 days (p = 0.018) and 7 days (p = 0.039). The average surgical times of implant sites preparation were: 10 (\ub1 1.4) minutes for the test sites, and 7.00 (\ub1 1.7) minutes for the control sites. In 69.2% of cases (9 of 13 patients) the operator has found advantages in terms of better access to the posterior sites, enhanced intraoperative visibility and insertion axis maintenance using the piezoelectric technique. The learning curve with piezodevice has seen a decrease in timing (rho = -0827, p = 0.001) from the first to the last intervention; whereas no significant difference was evaluated with the traditional method. Conclusion: Compared to traditional methods, piezoelectric technique enables optimal healing because it reduces the postsurgery swelling and discomfort. The average time necessary for the piezoelectric implant site osteotomy was approximately 3 minutes more than conventional technique
Characterization of carbon felt electrodes for vanadium redox flow batteries – A pore network modeling approach
Larmor frequency dressing by an anharmonic transverse magnetic field
We present a theoretical and experimental study of spin precession in the
presence of both a static and an orthogonal oscillating magnetic field, which
is nonresonant, not harmonically related to the Larmor precession, and of
arbitrary strength. Due to the intrinsic nonlinearity of the system, previous
models that account only for the simple sinusoidal case cannot be applied. We
suggest an alternative approach and develop a model that closely agrees with
experimental data produced by an optical-pumping atomic magnetometer. We
demonstrate that an appropriately designed nonharmonic field makes it possible
to extract a linear response to a weak dc transverse field, despite the scalar
nature of the magnetometer, which normally causes a much weaker, second-order
response.Comment: Published version has some minor changes; 22 pages and 8 picture
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