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Inventions (ISSN 2411-5134) is an international scientific peer-reviewed open access journal published quarterly online by MDPI.
- Open Access - free for readers, free publication for well-prepared manuscripts submitted in 2017.
- Rapid publication: manuscripts are peer-reviewed and a first decision provided to authors approximately 21 days after submission; acceptance to publication is undertaken in 4.7 days (median values for papers published in the first six months of 2018).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Latest Articles
A Robust Information Life Cycle Management Framework for Securing and Governing Critical Infrastructure Systems
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Inventions 2018, 3(4), 71; https://doi.org/10.3390/inventions3040071 (registering DOI) - 17 October 2018
Abstract
In modern societies, the rampant growth of the Internet, both on the technological and social level, has created fertile ground for the emergence of new types of risk. On top of that, it enhances pre-existing threats by offering new means for accessing and
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In modern societies, the rampant growth of the Internet, both on the technological and social level, has created fertile ground for the emergence of new types of risk. On top of that, it enhances pre-existing threats by offering new means for accessing and exploiting Critical Infrastructures. As the kinds of potential threats evolve, the security, safety and resilience of these infrastructures must be updated accordingly, both at a prevention, as well as a real-time confrontation level. Our research approaches the security of these infrastructures with a focus on the data and utilization of every possible piece of information that derives from this ecosystem. Such a task is quite daunting, since the quantity of data that requires processing resides in the Big Dataspace. To address this, we introduce a new well-defined Information Life Cycle in order to properly model and optimise the way information flows through a modern security system. This life cycle covers all the possible stages, starting from the collection phase up until the exploitation of information intelligence. That ensures the efficiency of data processing and filtering while increasing both the veracity and validity of the final outcome. In addition, an agile Framework is introduced that is optimised to take full advantage of the Information Life Cycle. As a result, it exploits the generated knowledge taking the correct sequence of actions that will successfully address possible threats. This Framework leverages every possible data source that could provide vital information to Critical Infrastructures by performing analysis and data fusion being able to cope with data variety and variability. At the same time, it orchestrates the pre-existing processes and resources of these infrastructures. Through rigorous testing, it was found that response time against hazards was dramatically decreased. As a result, this Framework is an ideal candidate for strengthening and shielding the infrastructures’ resilience while improving management of the resources used.
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A Novel Single-Stage Tandem Soft-Switching Converter with Low Input Current Distortion
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Inventions 2018, 3(4), 70; https://doi.org/10.3390/inventions3040070 (registering DOI) - 17 October 2018
Abstract
In order to improve the power factor and reduce the input current harmonics, power factor correction (PFC) converters are utilized. This paper introduces a single-stage continuous conduction mode (CCM) soft-switched power factor correction (PFC) converter with a tandem topology. The proposed topology has
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In order to improve the power factor and reduce the input current harmonics, power factor correction (PFC) converters are utilized. This paper introduces a single-stage continuous conduction mode (CCM) soft-switched power factor correction (PFC) converter with a tandem topology. The proposed topology has two operating modes, namely resonant operation mode and boost operation mode. Such a design and control realizes the zero-voltage switching (ZVS) and zero current switching (ZCS) of the power switches. The proposed topology has been introduced to reduce the total harmonic distortion (THD) of the input current further in the boost PFC converter under lower power and higher output voltage conditions. The simulation and experimental results are presented to verify the effectiveness of the performance of the proposed design and its control.
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Deep Learning Based Surveillance System for Open Critical Areas
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Inventions 2018, 3(4), 69; https://doi.org/10.3390/inventions3040069 - 11 October 2018
Abstract
How to automatically monitor wide critical open areas is a challenge to be addressed. Recent computer vision algorithms can be exploited to avoid the deployment of a large amount of expensive sensors. In this work, we propose our object tracking system which, combined
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How to automatically monitor wide critical open areas is a challenge to be addressed. Recent computer vision algorithms can be exploited to avoid the deployment of a large amount of expensive sensors. In this work, we propose our object tracking system which, combined with our recently developed anomaly detection system. can provide intelligence and protection for critical areas. In this work. we report two case studies: an international pier and a city parking lot. We acquire sequences to evaluate the effectiveness of the approach in challenging conditions. We report quantitative results for object counting, detection, parking analysis, and anomaly detection. Moreover, we report state-of-the-art results for statistical anomaly detection on a public dataset.
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Chemical-Free Extraction of Functional Mitochondria Using a Microfluidic Device
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Inventions 2018, 3(4), 68; https://doi.org/10.3390/inventions3040068 - 27 September 2018
Abstract
This paper proposes the use of a chip-based microfluidic device to extract functional and chemical free mitochondria. A simple microfluidic device was designed and fabricated. An osteosarcoma cybrid cell line was employed to demonstrate the efficiency of the proposed microfluidic device. The membrane
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This paper proposes the use of a chip-based microfluidic device to extract functional and chemical free mitochondria. A simple microfluidic device was designed and fabricated. An osteosarcoma cybrid cell line was employed to demonstrate the efficiency of the proposed microfluidic device. The membrane proteins (mitochondrial complex I-V and Tom20) and morphology of the extracted mitochondria were examined by Western blot and transmission electron microscopy (TEM), respectively. The purity and mitochondrial membrane potential of the extracted mitochondria were individually measured by 10-N-alkyl acridine orange and tetramethylrhodamine ethyl ester staining via flow cytometry. Experimental results revealed that expressed pattern of complex I–V in device-extracted mitochondria was close to that of mitochondria in total cell lysis and device extraction significantly prevented chemical modification of complex IV protein via a conventional kit, although device extract similar amounts of mitochondria to the conventional kit revealed by Tom20 expression. Furthermore, purity of device-extracted mitochondria was above 93.7% and mitochondria still retained normal activity after device extraction proven by expression of mitochondrial membrane potential as well as the entire mitochondrial morphology. These results confirmed that the proposed microfluidic device could obtain functional mitochondria without structural damage.
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Distributed Strain Sensing from Different Optical Fiber Configurations
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Inventions 2018, 3(4), 67; https://doi.org/10.3390/inventions3040067 - 25 September 2018
Abstract
Strain distributions were obtained from optical fibers arranged in three different configurations on transversely-loaded cantilevered beams. Traditional strain measurement sensors, such as strain gauges, are limited to measuring strain at discrete points on a structural member. However, distributed optical fibers can measure high
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Strain distributions were obtained from optical fibers arranged in three different configurations on transversely-loaded cantilevered beams. Traditional strain measurement sensors, such as strain gauges, are limited to measuring strain at discrete points on a structural member. However, distributed optical fibers can measure high spatial (<1 mm spacing) strain or temperature distributions. In this study, optical fibers in spiral, grid, and rosette configurations were bonded to aluminum cantilevered beams subjected to tip loads. Strain distributions from optical fiber sensors were measured using a swept wavelength coherent interferometric technique. The optical fiber strain measurements show good agreement with strain gauge measurements. The attributes of each sensor configuration are discussed.
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Cyber Physical Energy Systems Modules for Power Sharing Controllers in Inverter Based Microgrids
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Inventions 2018, 3(3), 66; https://doi.org/10.3390/inventions3030066 - 11 September 2018
Abstract
The Microgrids (MGs) are an effective way to deal with the smart grid challenges, including service continuity in the event of a grid interruption, and renewable energy integration. The MGs are compounded by multiple distributed generators (DGs), and the main control goals are
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The Microgrids (MGs) are an effective way to deal with the smart grid challenges, including service continuity in the event of a grid interruption, and renewable energy integration. The MGs are compounded by multiple distributed generators (DGs), and the main control goals are load demand sharing and voltage and frequency stability. Important research has been reported to cope with the implementation challenges of the MGs including the power sharing control problem, where the use of cybernetic components such as virtual components, and communication systems is a common characteristic. The use of these cybernetic components to control complex physical systems generates new modeling challenges in order to achieve an adequate balance between complexity and accuracy in the MG model. The standardization problem of the cyber-physical MG models is addressed in this work, using a cyber-physical energy systems (CPES) modeling methodology to build integrated modules, and define the communication architectures that each power sharing control strategy requires in an AC-MG. Based on these modules, the control designer can identify the signals and components that eventually require a time delay analysis, communication requirements evaluation, and cyber-attacks’ prevention strategies. Similarly, the modules of each strategy allow for analyzing the potential advantages and drawbacks of each power sharing control technique from a cyber physical perspective.
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PDMS-Based Microfluidic Devices for Cell Culture
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Inventions 2018, 3(3), 65; https://doi.org/10.3390/inventions3030065 - 6 September 2018
Abstract
Microfluidic technology has affirmed itself as a powerful tool in medical and biological research by offering the possibility of managing biological samples in tiny channels and chambers. Among the different applications, the use of microfluidics for cell cultures has attracted much interest from
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Microfluidic technology has affirmed itself as a powerful tool in medical and biological research by offering the possibility of managing biological samples in tiny channels and chambers. Among the different applications, the use of microfluidics for cell cultures has attracted much interest from scientists worldwide. Traditional cell culture methods need high quantities of samples and reagents that are strongly reduced in miniaturized systems. In addition, the microenvironment is better controlled by scaling down. In this paper, we provide an overview of the aspects related to the design of a novel microfluidic culture chamber, the fabrication approach based on polydimethylsiloxane (PDMS) soft-lithography, and the most critical issues in shrinking the size of the system.
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Belt-Driven Open Source Circuit Mill Using Low-Cost 3-D Printer Components
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Inventions 2018, 3(3), 64; https://doi.org/10.3390/inventions3030064 - 5 September 2018
Abstract
Barriers to inventing electronic devices involve challenges of iterating electronic designs due to long lead times for professional circuit board milling or high costs of commercial milling machines. To overcome these barriers, this study provides open source (OS) designs for a low-cost circuit
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Barriers to inventing electronic devices involve challenges of iterating electronic designs due to long lead times for professional circuit board milling or high costs of commercial milling machines. To overcome these barriers, this study provides open source (OS) designs for a low-cost circuit milling machine. First, design modifications for mechanical and electrical subsystems of the OS Distributed 3-D (D3D) Robotics prototyping system are provided. Next, Copper Carve, an OS custom graphical user interface, is developed to enable circuit board milling by implementing backlash and substrate distortion compensation. The performance of the OS D3D circuit mill is then quantified and validated for: positional accuracy, cut quality, feature accuracy, and distortion compensation. Finally, the return on investment is calculated for inventors using it. The results show by properly compensating for motion inaccuracies with Copper Carve, the machine achieves a motion resolution of 10 microns, which is more than adequate for most circuit designs. The mill is at least five times less expensive than all commercial alternatives and the material costs of the D3D mill are repaid from fabricating 20–43 boards. The results show that the OS circuit mill is of high-enough quality to enable rapid invention and distributed manufacturing of complex products containing custom electronics.
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A Soft-Switched DC/DC Converter Using Integrated Dual Half-Bridge with High Voltage Gain and Low Voltage Stress for DC Microgrid Applications
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Inventions 2018, 3(3), 63; https://doi.org/10.3390/inventions3030063 - 3 September 2018
Abstract
In this paper, a soft-switched boost converter including an integrated dual half-bridge circuit with high voltage gain and continuous input current is introduced that can be suitable for the applications requiring a wide voltage gain range, such as for the front-end of the
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In this paper, a soft-switched boost converter including an integrated dual half-bridge circuit with high voltage gain and continuous input current is introduced that can be suitable for the applications requiring a wide voltage gain range, such as for the front-end of the inverter in a DC microgrid to integrate renewable energy sources (RES). In the proposed converter, two half-bridge converters are connected in series at the output stage to enhance the voltage gain. Additionally, the balanced voltage multiplier stage is employed at the output to increase the voltage conversion ratio, as well as distribute the voltage stress across semiconductors; hence, switches with smaller on-resistance RDS(on) can be adopted resulting in an improvement in the efficiency. The converter takes advantage of the clamp circuit not only to confine the voltage stress of switches, but also to achieve the soft-switching, which leads to a reduction in the switching loss as well as the cost. The mentioned features make the proposed converter a proper choice for interfacing RES to the DC-link bus of the inverter. The operation modes, steady-state analysis, and design consideration of the proposed topology have been demonstrated in the paper. A 1-kW laboratory prototype was built using gallium nitride (GaN) transistors and silicon carbide (SiC) diodes to confirm the effectiveness of the proposed topology.
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Protection of Service-Oriented Environments Serving Critical Infrastructures
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Inventions 2018, 3(3), 62; https://doi.org/10.3390/inventions3030062 - 30 August 2018
Abstract
The emergence of service-oriented architectures has driven the shift towards a service-oriented paradigm, which has been adopted in several application domains. The advent of cloud computing facilities and recently of edge computing environments has increased the aforementioned paradigm shift towards service provisioning. In
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The emergence of service-oriented architectures has driven the shift towards a service-oriented paradigm, which has been adopted in several application domains. The advent of cloud computing facilities and recently of edge computing environments has increased the aforementioned paradigm shift towards service provisioning. In this context, various “traditional” critical infrastructure components have turned to services, being deployed and managed on top of cloud and edge computing infrastructures. However, the latter poses a specific challenge: the services of the critical infrastructures within and across application verticals/domains (e.g., transportation, health, industrial venues, etc.) need to be continuously available with near-zero downtime. In this context, this paper presents an approach for high-performance monitoring and failure detection of critical infrastructure services that are deployed in virtualized environments. The failure detection framework consists of distributed agents (i.e., monitoring services) to ensure timely collection of monitoring data, while it is enhanced with a voting algorithm to minimize the case of false positives. The goal of the proposed approach is to detect failures in datacenters that support critical infrastructures by targeting both the acquisition of monitoring data in a performant way and the minimization of false positives in terms of potential failure detection. The specific approach is the baseline towards decision making and triggering of actions in runtime to ensure service high availability, given that it provides the required data for decision making on time with high accuracy.
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A New Three-Level Flying-Capacitor Boost Converter with an Integrated LC2D Output Network for Fuel-Cell Vehicles: Analysis and Design
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Inventions 2018, 3(3), 61; https://doi.org/10.3390/inventions3030061 - 28 August 2018
Abstract
In this paper, a new three-level boost converter with continuous input current, common ground, reduced voltage stress on the power switches, and wide voltage gain range is proposed. The proposed converter is composed of a three-level flying-capacitor switching cell and an integrated LC
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In this paper, a new three-level boost converter with continuous input current, common ground, reduced voltage stress on the power switches, and wide voltage gain range is proposed. The proposed converter is composed of a three-level flying-capacitor switching cell and an integrated LC2D output network. The LC2D output network enhances the voltage gain of the converter and reduces the voltage stress on the power switches. The proposed converter is a good candidate to interface fuel cells to the dc-link bus of the three-phase inverter of an electric vehicle (EV). A full steady-state analysis of the proposed converter in the continuous conduction mode (CCM) is given in this paper. A 1.2 kW scaled-down laboratory setup was built using gallium nitride (GaN) transistors and silicon carbide (SiC) diodes to verify the feasibility of the proposed converter.
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A Review of Current Methods in Microfluidic Device Fabrication and Future Commercialization Prospects
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Inventions 2018, 3(3), 60; https://doi.org/10.3390/inventions3030060 - 28 August 2018
Abstract
Microfluidic devices currently play an important role in many biological, chemical, and engineering applications, and there are many ways to fabricate the necessary channel and feature dimensions. In this review, we provide an overview of microfabrication techniques that are relevant to both research
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Microfluidic devices currently play an important role in many biological, chemical, and engineering applications, and there are many ways to fabricate the necessary channel and feature dimensions. In this review, we provide an overview of microfabrication techniques that are relevant to both research and commercial use. A special emphasis on both the most practical and the recently developed methods for microfluidic device fabrication is applied, and it leads us to specifically address laminate, molding, 3D printing, and high resolution nanofabrication techniques. The methods are compared for their relative costs and benefits, with special attention paid to the commercialization prospects of the various technologies.
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Experimental Investigation of Impact Localization in Composite Plate Using Newly Developed Imaging Method
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Inventions 2018, 3(3), 59; https://doi.org/10.3390/inventions3030059 - 27 August 2018
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This paper focuses on impact localization of composite structures, which possess more complexity in the guided wave propagation due to the anisotropic behavior of composite materials. In this work, a composite plate was manufactured by using a compression molding process with proper pressure
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This paper focuses on impact localization of composite structures, which possess more complexity in the guided wave propagation due to the anisotropic behavior of composite materials. In this work, a composite plate was manufactured by using a compression molding process with proper pressure and temperature cycle. Eight layers of woven composite prepreg were used to manufacture the composite plate. A structural health monitoring (SHM) technique was implemented with piezoelectric wafer active sensors (PWAS) to detect and localize the impact on the plate. There were two types of impact event that were considered in this paper (a) low energy impact event (b) high energy impact event. Two clusters of sensors recorded the guided acoustic waves generated from the impact. The acoustic signals were then analyzed using a wavelet transform based time-frequency analysis. The proposed SHM technique successfully detected and localized the impact event on the plate. The experimentally measured impact locations were compared with the actual impact locations. An immersion ultrasonic scanning method was used to visualize the composite plate before and after the impact event. A high frequency 10 MHz 1-inch focused transducer was used to scan the plate in the immersion tank. Scanning results showed that there was no visible manufacturing damage in the composite plate. However, clear impact damage was observed after the high-energy impact event.
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Gorilla: An Open Interface for Smart Agents and Real-Time Power Microgrid System Simulations
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Inventions 2018, 3(3), 58; https://doi.org/10.3390/inventions3030058 - 27 August 2018
Abstract
A recurring issue when studying agent-based algorithms and strategies for Power Microgrid Systems is having to construct an interface between the agent domain and the electrical model domain being simulated. Many different tools exist for such simulations, each with its own special external
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A recurring issue when studying agent-based algorithms and strategies for Power Microgrid Systems is having to construct an interface between the agent domain and the electrical model domain being simulated. Many different tools exist for such simulations, each with its own special external interface. Although many interfacing efforts have been published before, many of them support only special cases, while others are too complex and require a long learning curve to be used for even simple scenarios. This work presents a simple programming application interface (API) that aims to provide programming access to the electrical system model for any real-time simulation tool, from any agent-based platform, or programming language. The simplicity of the interface stems from the assumption that the simulation happens in real-time and the agent domain is not being simulated. We propose four basic operations for the API: read, write, call, and subscribe/call-back. We tested these by supporting two examples. In one of the examples, we present a creative way to have the model access libraries that are not available in the simulated environment.
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Gene Delivery System Using Droplet Injector and Temperature-Controlled Planarian Holder
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Inventions 2018, 3(3), 57; https://doi.org/10.3390/inventions3030057 - 21 August 2018
Abstract
A microinjection system for gene delivery to a planarian was presented with materials widely used by manufacturers. The system consists of a nanoliter droplet generator/injector and a planarian holder. Glass capillary needles were used to consistently generate droplets and to inject droplets into
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A microinjection system for gene delivery to a planarian was presented with materials widely used by manufacturers. The system consists of a nanoliter droplet generator/injector and a planarian holder. Glass capillary needles were used to consistently generate droplets and to inject droplets into a planarian. The holder provides a low-temperature environment that immobilizes the planarian for injection. Our system was tested and showed successful injections of microbeads and droplets with double-stranded RNA into the planarian. The results demonstrated the capability of our system as an alternative for gene delivery for studying gene functions in planarians or other living objects for regenerative medicine studies.
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Low-Level Control of 3D Printers from the Cloud: A Step toward 3D Printer Control as a Service
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Inventions 2018, 3(3), 56; https://doi.org/10.3390/inventions3030056 - 19 August 2018
Abstract
Control as a Service (CaaS) is an emerging paradigm where low-level control of a device is moved from a local controller to the Cloud, and provided to the device as an on-demand service. Among its many benefits, CaaS gives the device access to
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Control as a Service (CaaS) is an emerging paradigm where low-level control of a device is moved from a local controller to the Cloud, and provided to the device as an on-demand service. Among its many benefits, CaaS gives the device access to advanced control algorithms which may not be executable on a local controller due to computational limitations. As a step toward 3D printer CaaS, this paper demonstrates the control of a 3D printer by streaming low-level stepper motor commands (as opposed to high-level G-codes) directly from the Cloud to the printer. The printer is located at the University of Michigan, Ann Arbor, while its stepper motor commands are calculated using an advanced motion control algorithm running on Google Cloud computers in South Carolina and Australia. The stepper motor commands are sent over the internet using the user datagram protocol (UDP) and buffered to mitigate transmission delays; checks are included to ensure accuracy and completeness of the transmitted data. All but one part printed using the cloud-based controller in both locations were hitch free (i.e., no pauses due to excessive transmission delays). Moreover, using the cloud-based controller, the parts printed up to 54% faster than using a standard local controller, without loss of accuracy.
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Design of a Hybrid AC/DC Microgrid Using HOMER Pro: Case Study on an Islanded Residential Application
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Inventions 2018, 3(3), 55; https://doi.org/10.3390/inventions3030055 - 14 August 2018
Abstract
This paper is concerned with the design of an autonomous hybrid alternating current/direct current (AC/DC) microgrid for a community system, located on an island without the possibility of grid connection. It is comprised of photovoltaic (PV) arrays and a diesel generator, AC loads,
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This paper is concerned with the design of an autonomous hybrid alternating current/direct current (AC/DC) microgrid for a community system, located on an island without the possibility of grid connection. It is comprised of photovoltaic (PV) arrays and a diesel generator, AC loads, and battery energy storage devices for ensuring uninterruptible power supply during prolonged periods of low sunshine. A multi-objective, non-derivative optimisation is considered in this residential application; the primary objective is the system cost minimisation, while it is also required that no load shedding is allowed. Additionally, the CO2 emissions are calculated to demonstrate the environmental benefit the proposed system offers. The commercial software, HOMER Pro, is utilised to identify the least-cost design among hundreds of options and simultaneously satisfy the secondary objective. A sensitivity analysis is also performed to evaluate design robustness against the uncertainty pertaining to fuel prices and PV generation. Finally, an assessment of the capabilities of the utilised optimisation platform is conducted, and a theoretical discussion sheds some light on the proposal for an enhanced design tool addressing the identified issues.
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Examining the Effect of Flow Rate Ratio on Droplet Generation and Regime Transition in a Microfluidic T-Junction at Constant Capillary Numbers
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Inventions 2018, 3(3), 54; https://doi.org/10.3390/inventions3030054 - 10 August 2018
Abstract
The focus of this work is to examine the effect of flow rate ratio (quotient of the dispersed phase flow rate over the continuous phase flow rate) on a regime transition from squeezing to dripping at constant capillary numbers. The effect of the
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The focus of this work is to examine the effect of flow rate ratio (quotient of the dispersed phase flow rate over the continuous phase flow rate) on a regime transition from squeezing to dripping at constant capillary numbers. The effect of the flow rate ratio on the volume of droplets generated in a microfluidic T-junction is discussed, and a new scaling law to estimate their volume is proposed. Existing work on a regime transition reported by several researchers focuses on the effect of the capillary number on regime transition, and the results that are presented in this paper advance the current understanding by indicating that the flow rate ratio is another parameter that dictates regime transition. In this paper, the transition between squeezing and dripping regimes is reported at constant capillary numbers, with a transition region identified between squeezing and dripping regimes. Dripping is observed at lower flow rate ratios and squeezing at higher flow rate ratios, with a transition region between the two regimes at flow rate ratios between 1 and 2. This is presented in a flow regime map that is constructed based on the observed mechanism. A scaling model is proposed to characterise droplet volume in terms of flow rate ratio and capillary number. The effect of flow rate ratio on the non-dimensional droplet volume is presented, and lastly, the droplet volume is expressed in terms of a range of parameters, such as the viscosity ratio between the dispersed and the continuous phase, capillary number, and the geometrical characteristics of the channels.
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Nonlinear Vibrations of Innovative One-Way Clutch in Vehicle Alternator
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Inventions 2018, 3(3), 53; https://doi.org/10.3390/inventions3030053 - 30 July 2018
Abstract
One-way clutches have been proposed for vehicle alternators. The clutch can play an important role in reducing vibrations of the vehicle engine accessory system, but the severe vibrations of the clutch subsystem limit its stability and durability. This paper investigates the nonlinear vibrations
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One-way clutches have been proposed for vehicle alternators. The clutch can play an important role in reducing vibrations of the vehicle engine accessory system, but the severe vibrations of the clutch subsystem limit its stability and durability. This paper investigates the nonlinear vibrations of a one-way clutch between the accessory pulley and the alternator shaft. The one-way clutch is modelled as a discontinuous stiffness system, and the simplified model is analyzed using discontinuous transform to determine the periodic, primary resonance and the sub and super harmonic resonance solutions. The typical system model is numerically solved and the spectrum and phase plots are characterized. The results give a big picture of and insights into the nonlinear vibration features of one-way clutch system. A relevant US patent is pending.
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Biocompatibility of 3D-Printed Methacrylate for Hearing Devices
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Inventions 2018, 3(3), 52; https://doi.org/10.3390/inventions3030052 - 27 July 2018
Abstract
The capacity of 3D printing (3DP) technologies to initiate speedy polymerization of solvent-free resins accounts for their utility in the manufacturing of medical devices. Nonetheless, independent biological evaluation of 3D-printed materials is recommended due to the unique parameters of the manufacturing process, which
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The capacity of 3D printing (3DP) technologies to initiate speedy polymerization of solvent-free resins accounts for their utility in the manufacturing of medical devices. Nonetheless, independent biological evaluation of 3D-printed materials is recommended due to the unique parameters of the manufacturing process, which can influence their physical, chemical and biological properties. In this study, E-Shell 450 clear methacrylate indicated for 3DP of hearing devices was examined for biological safety using zebrafish bioassays adapted to Organization for Economic Cooperation and Development (OECD) fish embryo test. In addition, the proprietary material was characterized for composition using headspace gas chromatography–mass spectrometry (GC–MS). To initiate the biological test, newly fertilized zebrafish eggs were cultured on non-treated and ethanol-treated methacrylates in glass petri dishes with ultrapure water, incubated at 28.5 °C and assessed for developmental endpoints of toxicity at 24 h intervals until 96 h. Toxicological data indicate that non-treated methacrylate is extremely toxic in zebrafish bioassays, whereas ethanol-treated counterpart showed a relative lower toxicity possibly due to ethanoic–aqueous interactions as observed by GC–MS. With the current influx of 3D printing materials, users are urged to exercise caution. Operators must also take cognizance of the potential toxicity of the chemicals used in 3DP and implement safety measures to limit their exposure.
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Inventions
Innovation in Machine Intelligence for Critical Infrastructures
Guest Editors: Anastasios Doulamis, Tania Stathaki, Athanasios VoulodimosDeadline: 31 October 2018
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Emerging Technologies Enabling Smart Grid
Guest Editors: Stefano Rinaldi, Emilio GhianiDeadline: 30 November 2018
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Electric Drives for Transportation Electrification and Industrial Systems
Guest Editors: Osama A. Mohammed, Ahmed Mohamed, Tarek YoussefDeadline: 31 December 2018
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Automatic Control and System Theory
Guest Editors: Luigi Fortuna, Maide BucoloDeadline: 31 January 2019