This work was partially supported by the European H2020 5GRANGE project (grant agreement 777137), and by the 5GCIty project (TEC2016-76795-C6-3-R) funded by the Spanish Ministry of Economy and Competitiveness. The work of Luis F. Gonzalez was partially supported by the European H2020 5GinFIRE project (grant agreement 732497).

<ol>
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(ETSI). , (2018).</li><li>Quick start installation and use guide. Open Source MANO Release FOUR Available from: <a target="_blank" href="https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR">https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR</a> (2019)</li><li>Open Source Software for Creating Private and Public Clouds. OpenStack Available from: <a target="_blank" href="https://docs.openstack.org/ocata">https://docs.openstack.org/ocata</a> (2019)</li><li>OpenStack Installation Tutorial for Ubuntu. OpenStack Available from: <a target="_blank" href="https://docs.openstack.org/ocata/install-guide-ubuntu/">https://docs.openstack.org/ocata/install-guide-ubuntu/</a> (2019)</li><li>Linphone. An Open Source VoIP SIP Softphone for voice/video calls and instant messaging. Linphone Available from: <a target="_blank" href="https://www.linphone.org">https://www.linphone.org</a> (2019)</li><li>An Open Source Project to easily build and deploy secure video-conferencing solutions. 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The authors have nothing to disclose.

One of the most important aspects of this experiment is the use of virtualization technologies and NFV standards with UAV platforms. NFV presents a new paradigm aiming to decouple the hardware dependency of the network functionalities, thus enabling the provision of these functionalities through softwarization. Accordingly, the experiment does not depend on the use of the hardware equipment specified in the protocol. Alternatively, different models of single board computers can be selected, as long as they are in line with the dimensions and the transport capacity of the UAVs and they support Linux containers.
Notwithstanding this flexibility in terms of hardware selection, all the content provided for the reproducibility of the experiment is oriented towards the use of open source technologies. In this context, the configuration aspects and the software tools are conditioned to the use of Linux as the operating system.
On the other hand, the experiment considers the interoperation of two different computational platforms (i.e., the UAV cloud platform and the core cloud platform) to provide a moderately complex network service. However, this is not strictly needed, and the protocol could be followed to support scenarios in which only the UAV cloud platform is involved.
In addition, the solution presented could potentially be used in other environments, where resource-constrained hardware platforms might be available with the needed capacity to execute virtualization containers (e.g., the Internet of Things, or IoT, environments). In any case, the applicability of this solution to different environments and its potential adaptations will require a careful study in a case-by-case basis.
Finally, it should be noted that the results presented have been obtained in a laboratory environment and with the UAV devices grounded or following a limited and well-defined flight plan. Other scenarios involving outdoor deployments may introduce conditions affecting the stability of the flight of the UAVs, and hence the performance of the IP telephony service.

One of the most coveted goals within the new era of the mobile communications (most commonly known as the 5th mobile generation or 5G) is to be able to provide robust information technology services in situations where the primary telecommunications infrastructure may not be available (e.g., due to an emergency). In this context, the UAVs are receiving increasing attention from the research community due to their inherent versatility. There are numerous works that use these devices as a cornerstone for the provision of a large variety of services. For instance, the literature has analyzed the capacity of these devices to build an aerial communication infrastructure to accommodate multimedia services1,2,3. Furthermore, prior research has shown how the cooperation among several UAVs can extend the functionality of different communication services such as surveillance4, collaborative search and rescue5,6,7,8, or agribusiness9.
On the other hand, the NFV technology has acquired great significance within the telecom operators as one of the 5G key enablers. NFV represents a paradigmatic change regarding the telecommunications infrastructure by alleviating the current dependency of network appliances on specialized hardware through the softwarization of the network functionalities. This enables a flexible and agile deployment of new types of communication services. To this purpose, the European Telecommunications Standards Institute (ETSI) formed a specification group to define the NFV architectural framework10. Additionally, the ETSI currently hosts the Open Source Mano (OSM) group11, which is in charge of developing an NFV Management and Orchestration (MANO) software stack aligned with the definition of the ETSI NFV architectural framework.
Given all the aforementioned considerations, the synergic convergence between UAVs and NFV technologies is currently being studied in the development of novel network applications and services. This is illustrated by several research works in the literature that point out the advantages of these types of systems14,15,16, identify the challenges of this convergence and its missing aspects, highlight future research lines on this topic17, and present pioneer solutions based on open source technologies.
In particular, the integration of NFV technologies into the UAV arena enables the rapid and flexible deployment of network services and applications over delimited geographic areas (e.g., an IP telephony service). Following this approach, a number of UAVs can be deployed over a specific location, transporting compute platforms as payload (e.g., small-size single board computers). These compute platforms would provide a programmable network infrastructure (i.e., an NFV infrastructure) over the deployment area, supporting the instantiation of network services and applications under the control of a MANO platform.
Notwithstanding the benefits, the realization of this view presents a set of fundamental challenges that needs to be carefully addressed, such as the appropriate integration of these compute platforms as an NFV infrastructure, using an existing NFV software stack, so that an NFV orchestration service can deploy virtual functions on the UAVs; the constraints in terms of the computational resources provided by the compute platforms, as the UAVs transporting them may typically present limitations in terms of size, weight, and computing capacity of payload equipment; the proper placement of the virtual functions onto UAVs (i.e., selecting the best UAV candidate to deploy a particular virtual function); the maintenance of the control communications with the UAVs in order to manage the lifecycle of the VNFs in spite of the potentially intermittent availability of network communications with them (e.g., caused by mobility and battery constraints); the limited operation time of the UAVs due to their battery consumption; and the migration of the virtual functions when a UAV needs to be replaced due to its battery exhaustion. These benefits and challenges are detailed in previous work18,19 that includes the design of an NFV system capable of supporting the automated deployment of network functions and services on UAV platforms, as well as the validation of the practical feasibility of this design.
In this context, this paper focuses on describing a protocol to enable the automated deployment of moderately complex network services over a network of UAVs using the NFV standards and open source technologies. To illustrate the different steps of the protocol, a re-elaboration of an experiment presented in Nogales et al.19 is presented, consisting of the deployment of an IP telephony service. To aid the reproducibility of this work, real flight is considered as optional in the presented procedure, and performance results are obtained with the UAV devices on the ground. Interested readers should be able to replicate and validate the execution of the protocol, even in a controlled laboratory environment.
Figure 1 illustrates the network service designed for this procedure. This network service is built as a composition of specific softwarization units (categorized within the NFV paradigm as Virtual Network Functions, or VNFs) and provides the functionality of an IP telephony service to users in the vicinity of the UAVs. The VNF composing the service are defined as follows:
<ul>
	<li>Access Point VNF (AP-VNF): This VNF provides a Wi-Fi access point to end-user equipment (i.e., IP phones in this experiment).</li>
	<li>IP telephony server VNF (IP-telephony-server-VNF): It is responsible for managing the call signaling messages that are exchanged between IP phones to establish and terminate a voice call.</li>
	<li>Domain Name System VNF (DNS-VNF): This VNF provides a name resolution service, which is typically needed in IP telephony services.</li>
	<li>Access router VNF (AR-VNF): provides network routing functionalities, supporting the exchange of traffic (i.e., call signaling in this experiment) between the IP phones and the telecommunication operator domain.</li>
	<li>Core router VNF (CR-VNF): provides network routing functionalities in the telecommunication operator domain, offering access to operator-specific services (i.e., the IP telephony server) and external data networks.</li>
</ul>
Moreover, Figure 1 presents the physical devices used for the experiment, how they are interconnected, and the specific allocation of VNFs to devices.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>AR. Drone 2.0 - Elite edition</td>
			<td>Parrot</td>
			<td></td>
			<td>UAV used in the experiment to transport the RPis and thus, provide mobility to the compute units of the UAV cloud platform.</td>
		</tr>
		<tr>
			<td>Bebop 2</td>
			<td>Parrot</td>
			<td></td>
			<td>UAV used in the experiment to transport the RPis and thus, provide mobility to the compute units of the UAV cloud platform.</td>
		</tr>
		<tr>
			<td>Commercial Intel Core Mini-ITX Computer</td>
			<td>Logic Suppy</td>
			<td></td>
			<td>Computer server which hosts the OpenStack controller node (being executed as a VM) of the experiment&#39;s UAV cloud platform. In addition, another unit of this equipment (along with the RPis) conforms the computational resources of the UAV cloud platform.</td>
		</tr>
		<tr>
			<td>Linux Containers (LXC)</td>
			<td>Canonical Ltd.</td>
			<td></td>
			<td>(Software) Virtualization technology that enables the supply of the Virtual Network Functions detailed in the experiment. Source-code available online: https://linuxcontainers.org</td>
		</tr>
		<tr>
			<td>Lithium Battery Pack Expansion Board. Model KY68C-UK</td>
			<td>Kuman</td>
			<td></td>
			<td>Battery-power supply HAT (Hardware Attached on Top) for the computation units of the UAV cloud platform (i.e., the Raspberry Pis). In addition, this equipment encompasses the case used to attach the compute units (i.e., the Raspberry PIs or RPis) to the UAVs.</td>
		</tr>
		<tr>
			<td>MacBook Pro</td>
			<td>Apple</td>
			<td></td>
			<td>Commodity laptop utilized during the experiment to obtain and gather the results as described in the manuscript.</td>
		</tr>
		<tr>
			<td>ns-3 Network Simulator</td>
			<td>nsnam</td>
			<td></td>
			<td>(Software) A discrete-event simulator network simulator which provides the underlying communication substrate to the emulation station explained in the &#34;Protocol&#34; section (more specifically in the step &#34;2. Validate the functionality of the softwarization units via Emulation&#34;). Source-code available online: https://www.nsnam.org</td>
		</tr>
		<tr>
			<td>Open Source MANO (OSM) - Release FOUR</td>
			<td>ETSI OSM - Open source community</td>
			<td></td>
			<td>(Software) Management and Orchestration (MANO) software stack of the NFV system configured in the experiment. Source-code available online: https://osm.etsi.org/wikipub/index.php/OSM_Release_FOUR</td>
		</tr>
		<tr>
			<td>OpenStack - Release Ocata</td>
			<td>OpenStack - Open source community</td>
			<td></td>
			<td>(Software) Open source software used for setting up both the UAV cloud platform and the core cloud within the experiment. Source-code available online: https://docs.openstack.org/ocata/install-guide-ubuntu</td>
		</tr>
		<tr>
			<td>Ping</td>
			<td>Open source tool</td>
			<td></td>
			<td>(Software) An open source test tool, which verifies the connectivity between two devices connected through a communications network. In addition, this tool allows to assess the network performance since it calculates the Round Trip Time (i.e., the time taken to send and received a data packet from the network). Source-code available online: https://packages.debian.org/es/sid/iputils-ping</td>
		</tr>
		<tr>
			<td>Power Edge R430</td>
			<td>Dell</td>
			<td></td>
			<td>High-profile computer server which provides the computational capacity within the core cloud platform presented in the experiment.</td>
		</tr>
		<tr>
			<td>Power Edge R630</td>
			<td>Dell</td>
			<td></td>
			<td>Equipment used for hosting the virtual machine (VM) on charge of executing the MANO stack. In addition, the OpenStack controller node is also executed as a VM in this device. Note that the use of this device is not strictly needed. The operations carried out by this device could be done by a lower performance equipment due to the non-high resource specifications of the before mentioned VMs.</td>
		</tr>
		<tr>
			<td>Prestige 2000W</td>
			<td>ZyXEL</td>
			<td></td>
			<td>Voice over IP Wi-FI phone, compatible with the IEEE 802.11b wireless communications standard. This device is utilized to carry out the VoIP call through the network service hosted by platform described for the execution of the experiment.</td>
		</tr>
		<tr>
			<td>Raspberry PI. Model 3b</td>
			<td>Raspberry Pi Foundation</td>
			<td></td>
			<td>Selected model of Single Board Computer (SBC) used for providing the computational capacity to the experiment&#39;s UAV cloud platform.</td>
		</tr>
		<tr>
			<td>SIPp</td>
			<td>Open source tool</td>
			<td></td>
			<td>(Software) An open source test tool, which generates SIP protocol traffic. This tool allows to verify the proper support of the signalling traffic required in an IP telephony service such as the one deployed in the experiment. Source-code available online: http://sipp.sourceforge.net</td>
		</tr>
		<tr>
			<td>Tcpdump</td>
			<td>Open source tool</td>
			<td></td>
			<td>(Software) An open source tool that enables the capture and analysis of the network traffic. Source-code available online: https://www.tcpdump.org</td>
		</tr>
		<tr>
			<td>Trafic</td>
			<td>Open source tool</td>
			<td></td>
			<td>(Software) An open souce flow scheduler that is used for validating the capacity of the network service deployed to process data traffic generated during an IP telephony call. Source-code available online at: https://github.com/5GinFIRE/trafic</td>
		</tr>
	</tbody>
</table>

automated deployment of an internet protocol telephony service on unmanned aerial vehicles using network functions virtualization

The Network Function Virtualization (NFV) paradigm is one of the key enabling technologies in the development of the 5th generation of mobile networks. This technology aims to lessen the dependence on hardware in the provision of network functions and services by using virtualization techniques that allow the softwarization of those functionalities over an abstraction layer. In this context, there is increasing interest in exploring the potential of unmanned aerial vehicles (UAVs) to offer a flexible platform capable of enabling cost-effective NFV operations over delimited geographic areas.
To demonstrate the practical feasibility of utilizing NFV technologies in UAV platforms, a protocol is presented to set up a functional NFV environment based on open source technologies, in which a set of small UAVs supply the computational resources that support the deployment of moderately complex network services. Then, the protocol details the different steps needed to support the automated deployment of an internet protocol (IP) telephony service over a network of interconnected UAVs, leveraging the capacities of the configured NFV environment. Experimentation results demonstrate the proper operation of the service after its deployment. Although the protocol focuses on a specific type of network service (i.e., IP telephony), the described steps may serve as a general guide to deploy other type of network services. On the other hand, the protocol description considers concrete equipment and software to set up the NFV environment (e.g., specific single board computers and open source software). The utilization of other hardware and software platforms may be feasible, although the specific configuration aspect of the NFV environment and the service deployment may present variations with respect to those described in the protocol.

Based on the data obtained during the execution of the experiment, in which a real VoIP call is executed and following the steps indicated by the protocol to gather this information, Figure 2 depicts the cumulative distribution function of the end-to-end delay measured between two end-user equipment items (i.e., a commodity laptop and an IP telephone). This user equipment represents two devices that are interconnected through the AP VNFs of the deployed network service. More than 80% of the end-to-end delay measurements were below 60 ms, and none of them were higher than 150 ms, which guarantees appropriate delay metrics for the execution of a voice call.
Figure 3 illustrates the exchange of DNS and SIP signaling messages. These messages correspond to the registration of one of the users in the IP telephony server (i.e., the user whose IP phone is connected to the AP VNF where the &#34;tcpdump&#34; tool is running) and to the establishment of the voice call.
Finally, Figure 4 and Figure 5 show the data traffic captured during the call. In particular, the first one represents the constant stream of voice packets transmitted and received by one of the wireless phones during the call, whereas the latter illustrates the jitter in the forward direction with an average value lower than 1 ms.
The results that were obtained in the experiment for the delay figures (end-to-end delay and jitter) satisfy the recommendations specified by the International Telecommunication Union - Telecommunication Standardization Sector (ITU-T)35. Accordingly, the voice call progressed with no glitches and good sound quality. This experiment validated the practical feasibility of using NFV technologies and UAVs to deploy a functional IP telephony service.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60425/60425fig01.jpg" /> 
Figure 1: Overview of the network service, depicting the VNFs, the entities in which they are executed, and the virtual networks needed for the provision of the IP telephony service. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/60425/60425fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/60425/60425fig02.jpg" /> 
Figure 2: End-to-end delay. Representation of the end-to-end delay offered to the end-user equipment connected to the AP VNFs. For this purpose, the cumulative distribution function of the end-to-end delay has been computed from the measured RTT samples obtained with the &#34;ping&#34; command line tool. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/60425/60425fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/60425/60425fig03.jpg" /> 
Figure 3: User registration and call signaling messages. Illustration of the signaling traffic (DNS and SIP) exchanged to register a user in the IP telephony server and to create and terminate the multimedia session that supports the execution of the voice call. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/60425/60425fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/60425/60425fig04.jpg" /> 
Figure 4: Stream of voice packets. Representation of the voice traffic exchanged during the call, measured at one of the AP VNFs. (Abbreviations: RX = receive, RX = transmit, RTP = real-time transport protocol). <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/60425/60425fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/60425/60425fig05.jpg" /> 
Figure 5: Evolution of the network jitter during the call. Representation of the jitter experienced by the transmitted voice packets in the forward direction from one phone to the other. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/60425/60425fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization at JoVE.com

Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization

The objective of the described protocol is twofold: to configure a network functions virtualization environment using unmanned aerial vehicles as computational entities providing the underlying structure to execute virtualized network functions and to use this environment to support the automated deployment of a functional internet protocol telephony service over the aerial vehicles.

The Network Function Virtualization (NFV) paradigm is one of the key enabling technologies in the development of the 5th generation of mobile networks. ...

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Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

7.9K Views.  Universidad Carlos III de Madrid. The objective of the described protocol is twofold: to configure a network functions virtualization environment using unmanned aerial vehicles as computational entities providing the underlying structure to execute virtualized network functions and to use this environment to support the automated deployment of a functional internet protocol telephony service over the aerial vehicles.

Video: Automated Deployment of an Internet Protocol Telephony Service on Unmanned Aerial Vehicles Using Network Functions Virtualization

Setting Limits on Supersymmetry Using Simplified Models

Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to generalize because of the complexity of single points. Therefore, more phenomenological, simplified models are becoming popular for setting experimental limits, as they have clearer physical interpretations. The use of these simplified model limits to set a real limit on a concrete theory has not, however, been demonstrated. This paper recasts simplified model limits into limits on a specific and complete supersymmetry model, minimal supergravity. Limits obtained under various physical assumptions are comparable to those produced by directed searches. A prescription is provided for calculating conservative and aggressive limits on additional theories. Using acceptance and efficiency tables along with the expected and observed numbers of events in various signal regions, LHC experimental results can be recast in this manner into almost any theoretical framework, including nonsupersymmetric theories with supersymmetry-like signatures.

This paper demonstrates a protocol for recasting experimental simplified model limits into conservative and aggressive limits on an arbitrary new physics model. Publicly available LHC experimental results can be recast in this manner into limits on almost any new physics model with a supersymmetry-like signature.

Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

Data Acquisition Protocol for Determining Embedded Sensitivity Functions

The effectiveness of many structural health monitoring techniques depends on the placement of sensors and the location of input forces. Algorithms for determining optimal sensor and forcing locations typically require data, either simulated or measured, from the damaged structure. Embedded sensitivity functions provide an approach for determining the best available sensor location to detect damage with only data from the healthy structure. In this video and manuscript, the data acquisition procedure and best practices for determining the embedded sensitivity functions of a structure is presented. The frequency response functions used in the calculation of the embedded sensitivity functions are acquired using modal impact testing. Data is acquired and representative results are shown for a residential scale wind turbine blade. Strategies for evaluating the quality of the data being acquired are provided during the demonstration of the data acquisition process.

The data acquisition procedure for determining embedded sensitivity functions is described. Data is acquired and representative results are shown for a residential scale wind turbine blade.

The effectiveness of many structural health monitoring techniques depends on the placement of sensors and the location of input forces. Algorithms for ...

Protocol of Electrochemical Test and Characterization of Aprotic Li-O2 Battery

We demonstrate a method for electrochemical testing of an aprotic Li-O2 battery. An aprotic Li-O2 battery is made of a Li-metal anode, an aprotic electrolyte, and an O2-breathing cathode. The aprotic electrolyte is a solution of lithium salt with aprotic solvent; and porous carbon is commonly used as the cathode substrate. To improve the performance, an electrocatalyst is deposited onto the porous carbon substrate by certain deposition methods, such as atomic layer deposition (ALD) and wet-chemistry reaction. The as-prepared cathode materials are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray absorption near edge structure (XANES). A Swagelok-type cell, sealed in a glass chamber filled with pure O2, is used for the electrochemical test on a battery test system. The cells are tested under either capacity-controlled mode or voltage controlled mode. The reaction products are investigated by electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and Raman spectroscopy to study the possible pathway of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). This protocol demonstrates a systematic and efficient arrangement of routine tests of the aprotic Li-O2 battery, including the electrochemical test and characterization of battery materials.

Protocol of Electrochemical Test and Characterization of Aprotic Li-O2 Battery

A protocol for the electrochemical testing of an aprotic Li-O2 battery with the preparation of electrodes and electrolytes and an introduction of the frequently used methods of characterization is presented here.

We demonstrate a method for electrochemical testing of an aprotic Li-O2 battery. An aprotic Li-O2 battery is made of a Li-metal anode, an aprotic ...

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

We present protocols to be used in the measurement of spray droplet size from agricultural nozzles used in both aerial and ground based agrochemical applications. These methods presented were developed to provide consistent and repeatable droplet size data both inter- and intra-laboratory, when using laser diffraction systems.

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to ...

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm. A key aspect of such a nanofabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. Moreover, the single-shot fabrication makes it immune to mechanical instabilities and other fabrication imperfections. Such periodic nano-craters on nanofiber, act as a 1-D PhC and enable strong and broadband reflection while maintaining the high transmission out of the stopband. We also present a method to control the profile of the nano-crater array to fabricate apodized and defect-induced PhC cavities on the nanofiber. The strong confinement of the field, both transverse and longitudinal, in the nanofiber-based PhC cavities and the efficient integration to the fiber networks, may open new possibilities for nanophotonic applications and quantum information science.

We present a protocol for fabricating 1-D photonic crystal cavities on subwavelength diameter silica fibers (optical nanofibers) using femtosecond laser-induced ablation.

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using ...

Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is &#62;1.5 carbon weight % (standard deviation &#177; 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

Here, we present the protocol for in situ measurement of soil carbon using the neutron-gamma technique for single point measurements (static mode) or field averages (scanning mode). We also describe system construction and elaborate data treatment procedures.

The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of ...

The Modular Design and Production of an Intelligent Robot Based on a Closed-Loop Control Strategy

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach their targets. In recent years, reliance upon robots in both daily life and industry has increased. The protocol proposed in this paper describes the design and production of a handling robot with an intelligent search algorithm and an autonomous identification function.
First, the various working modules are mechanically assembled to complete the construction of the work platform and the installation of the robotic manipulator. Then, we design a closed-loop control system and a four-quadrant motor control strategy, with the aid of debugging software, as well as set steering gear identity (ID), baud rate and other working parameters to ensure that the robot achieves the desired dynamic performance and low energy consumption. Next, we debug the sensor to achieve multi-sensor fusion to accurately acquire environmental information. Finally, we implement the relevant algorithm, which can recognize the success of the robot&#39;s function for a given application.
The advantage of this approach is its reliability and flexibility, as the users can develop a variety of hardware construction programs and utilize the comprehensive debugger to implement an intelligent control strategy. This allows users to set personalized requirements based on their needs with high efficiency and robustness.

We present a protocol on modular design and production of intelligent robots to help scientific and technical workers design intelligent robots with special production tasks based on personal needs and individualized design.

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach ...

An Available Technique for Preparation of New Cast MnCuNiFeZnAl Alloy with Superior Damping Capacity and High Service Temperature

Manganese (Mn)-copper (Cu)-based alloys have been found to have&#160;damping capacity and can be used to reduce harmful vibrations and noise effectively. M2052 (Mn-20Cu-5Ni-2Fe, at%) is an important branch of Mn-Cu-based alloys, which possesses both excellent damping capacity and processability. In recent decades, lots of studies have been carried out on the performance optimization of M2052, improving the damping capacity, mechanical properties, corrosion resistance, and service temperature, etc. The major methods of performance optimization are alloying, heat treatment, pretreatment, and different ways of molding etc., among which alloying, as well as adopting a reasonable heat treatment, is the simplest and most effective method to obtain perfect and comprehensive performance. To obtain the M2052 alloy with excellent performance for casting molding, we propose to add Zn and Al to the MnCuNiFe alloy matrix and use a variety of heat treatment methods for a comparison in the microstructure, damping capacity, and service temperature. Thus, a new type of cast-aged Mn-22.68Cu-1.89Ni-1.99Fe-1.70Zn-6.16Al (at.%) alloy with&#160;superior damping capacity and high service temperature is obtained by an optimized heat treatment method. Compared with the forging technique, cast molding is simpler and more efficient, and the damping capacity of this as-cast alloy is excellent. Therefore, there is a suitable reason to think that it is a good choice for engineering applications.

Here we present a protocol to obtain a novel Mn-Cu-based alloy with excellent comprehensive performances by a high-quality smelting technology and reasonable heat treatment methods.

Manganese (Mn)-copper (Cu)-based alloys have been found to have&#160;damping capacity and can be used to reduce harmful vibrations and noise effectively. ...

Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers

Soft pneumatic network actuators have become one of the most promising actuation devices in soft robotics which benefits from their large bending deformation and low input. However, their monotonous bending motion form in two-dimensional (2-D) space keeps them away from wide applications. This paper presents a detailed fabrication method of soft pneumatic network actuators with oblique chambers, to explore their motions in three-dimensional (3-D) space. The design of oblique chambers enables actuators with tunable coupled bending and twisting capabilities, which gives them the possibility to move dexterously in flexible manipulators, to become biologically inspired robots and medical devices. The fabrication process is based on the molding method, including the silicone elastomer preparation, chamber and base parts fabrication, actuator assembly, tubing connections, checks for leaks, and actuator repair. The fabrication method guarantees the rapid manufacturing of a series of actuators with only a few modifications in the molds. The test results show the high quality of the actuators and their prominent bending and twisting capabilities. Experiments of the gripper demonstrate the advantages of the development in adapting to objects with different diameters and providing sufficient friction.

Here we present a fabrication method of soft pneumatic network actuators with oblique chambers. The actuators are capable of generating coupled bending and twisting motions, which broadens their application in soft robotics.