Electronic Box Research Articles

Thermodynamics and efficiency of an autonomous on-chip Maxwell's demon.

In his famous letter in 1870, Maxwell describes how Joule’s law can be violated “only by the intelligent action of a mere guiding agent”, later coined as Maxwell’s demon by Lord Kelvin. In this letter we study thermodynamics of information using an experimentally feasible Maxwell’s demon setup based a single electron transistor capacitively coupled to a single electron box, where both the system and the Demon can be clearly identified. Such an engineered on-chip Demon measures and performes feedback on the system, which can be observed as cooling whose efficiency can be adjusted. We present a detailed analysis of the system and the Demon, including the second law of thermodynamics for bare and coarse grained entropy production and the flow of information as well as efficiency of information production and utilization. Our results demonstrate how information thermodynamics can be used to improve functionality of modern nanoscale devices.

Cloud-based harvest management information system for hand-harvested specialty crops

The harvest process for specialty crops is generally one of intensive activity because many people are required for harvest and packing, and the harvest window is brief due to the high perishability of the produce. Herein we present a cloud-based Harvest Management Information System (HMIS) that combines a novel real-time Portable Labor Monitoring System (PLMS) with a cloud-based harvest management software. The PLMS comprised of three key elements (1) a self-leveling scale, (2) electronic control box, and (3) a frame that supports all hardware. The electronic control box includes: (i) a RFID reader, (ii) a LCD display, (iii) a thermal printer, (iv) a GPS module, and (v) a communication system. RFID tags, containing unique ID numbers, embedded within rubber wrist bands, are worn by pickers. This system can read a picker’s ID (RFID bracelet), measure the weight of fruit, and record the time and location (optional) of every fruit ‘transaction’ (i.e., every time a picker brings a bucket of fruit to the collection bin). The collected data can be transmitted wirelessly to the server in real-time. The cloud-based software receives and processes the PLMS data on labor activities, visualizes the collected data, and can extract the data necessary for management information and automated filling of documents (e.g. payroll, yield maps). The HMIS is unique in its ability to: (1) accurately credit pickers for the fruit they have harvested in the field without impeding or altering the harvest process, (2) streamline data entry to payroll, (3) provide real-time tracking of harvest, yield mapping, and traceability, and, (4) generate precise and reliable harvest efficiency data. This integrated system was evaluated in sweet cherry, blueberry and apple orchards in Washington, USA. The weight of harvested fruit, time and location of every fruit drop were calculated accurately; all the data were transmitted wirelessly to the server and no errors were recorded.

Aviation Cyber Security: A Constructive Look at the Work of ICAO

The Economist of 4 November 2014 speaks of ‘cyberjacking’ – a phenomenon that refers to the equivalent of hijacking an aircraft with the use of cyber technology. This could happen from outside the aircraft or from the inside. The catalyst in this instance is the increasing popularity with passengers of internet connectivity on board for work, games, movies et al. The article also mentions that internet signals are routed through existing communications architecture, such as the Aircraft Communications Addressing and Reporting System (ACARS), or the Automatic Dependent Surveillance-Broadcast (ADS-B), which is an anti-collision system, which, both being information communications systems can, in theory be targets of cyber-attacks. In its later edition of 21 May 2015 the same journal highlighted that a hacker had identified a weakness with the in-flight entertainment (IFE) systems on Boeing 737-800, 737-900, 757-200 and Airbus A320 aircraft. He had demonstrated this fact by accessing the systems by plugging a laptop into one of the electronic boxes usually found under the seats either side of the aisle. Once connected, the hacker claims to have accessed other systems on the aircraft. None of these claims have been validated by the scientific community nor have they been put into practice by terrorists or criminals against civil air transport. Nonetheless, this may be a sign of things to come, particularly when one considers that the National Aeronautics and Space Administration’s computers have been hacked in the past and that all computer systems of SONY were hacked in the recent past, allegedly by a foreign State sponsored hacking exercise. As this article discusses, there has been at least one confirmed cyber-attack on a computer system of a commercial airline. The International Civil Aviation Organization(ICAO) has been active in the field of prevention of cyber terrorism, which this article will elaborate on, with some constructive suggestions.

Feasibility and usability of a wearable orthotic for stroke survivors with hand impairment

Purpose: The concept of a vibrating wristband, to improve dextrous hand function of stroke survivors, was recently proposed with clinical results and is referred to as ‘TheraBracelet’ in this paper. The purpose of this study was to demonstrate feasibility of a portable, wearable TheraBracelet, and to apply usability evaluation techniques to assess potential demands of TheraBracelet and to identify critical improvement needs of the prototype. Method: A prototype was developed with a vibrating element housed in an elastic wristband and connected to a wearable electronics box via a cable. Expectation for TheraBracelet and evaluation of the prototype were obtained from 10 chronic stroke survivors using surveys before and after using the prototype and House of Quality analysis. Results: The survey for expectation showed stroke survivors’ willingness to try out TheraBracelet at a low cost. The survey evaluating the prototype showed that the current prototype was overall satisfactory with a mean rating of 3.7 out of 5. The House of Quality analysis revealed that the priority improvement needs for the prototype are to improve clinical knowledge on long-term effectiveness, reduce cost, ease donning/doffing and waterproof.Conclusions: This study presents a potential for a low-cost wearable hand orthotic likable by stroke survivors.Implications for RehabilitationFeasibility for a portable wearable wristband-type hand orthotic was demonstrated.The survey showed stroke survivors are willing to try such an orthotic at low cost.The current prototype was rated overall satisfactory by stroke survivors.This study provides a potential for a low-cost wearable hand orthotic likable by stroke survivors.

The ionosphere measurement technology of Langmuir probe on China seismo-electromagnetic satellite

China seismo-electromagnetic satellite (CSES) is launched to detect the electromagnetic environment in space for the study of seismic early warning. Langmuir probe is one of the payloads of the CSES satellite, and it is the first time that the Langmuir probe technique has been used in the Chinese satellite. The use of the Langmuir probe is to measure the space plasma parameters, such as electron density (Ne), electron temperature (Te), and to identify the instantaneous change of the space plasma. The Langmuir probe payload is composed of three parts, i.e., two sensors, two rods, and one electronics box. The sensor is installed at the top of the rod to extend out of the satellite surface, and is parallel to the direction of the satellite orbit. The electronics box is installed inside the satellite which includes the sweep voltage circuit, sensor signal circuit, DPU control and processing circuit, the satellite interface circuit, power supply circuit, etc. The sensor is spherical. Its upper hemisphere is a collecting electrode, and its lower hemisphere is a protective electrode. The same sweep voltage is applied to the upper hemisphere and the lower one which can eliminate the terminal effect of the connecting point between the traditional spherical structure and the rod. The diameters of the two sensors are respectively 50 and 10 mm, and the surface areas of the two sensors are respectively 1/2000 and 1/13000 times the satellite surface area. The stability of the satellite ground potential is not affected by the sweep voltages on the sensors. In addition, TiN material is coated on the sensor surface to ensure a uniform surface work function, and to prevent the space atomic oxygen erosion. The decontamination function is designed for the Langmuir probe to eliminate the possible pollution on the orbit. A positive 100 V voltage is applied to the sensor to accelerate electrons to bombard the sensor surface, thereby removing the contamination from the sensor surface. The advantage of the electron bombardment effect is that the TiN film is not damaged, meanwhile the positive 100 V voltage has high reliability and safety on orbit. The decontamination function has been proved to be effective by the test in Italy National Institute for Astrophysics-Institute for Space Astrophysics and Planetology (INAF-IAPS). The plasma environment calibration test of the Langmuir probe is carried out in INAF-IAPS. We measure the electron density and temperature at three different distances from the plasma source, and compare the results with the measured results of the INAF-IAPS reference Langmuir probe. Results show that the test data of our Langmuir probe are consistent with the INAF-IAPS reference data. Our Langmuir probe design is proved to be feasible to achieve the missions of the satellite.

Dose Measured On-Board INTEGRAL After More Than 12 Years in Space

—The INTEGRAL satellite was launched on October 17, 2002 and all on-board instruments are still operating successfully after more than 12 years, which represents more than a full solar cycle. This paper deals with the dose measured by 8 RadFETs mounted in 2 electronic boxes, which control the detector plane of the IBIS/ISGRI camera. These measurements are compared to what could be predicted before the launch, by using the dose profile , as determined by common space environment software, and also a detailed sectorial analysis of shielding materials around the RadFETs by means of a Monte-Carlo based model of the whole spacecraft. In this study, the sectorial analysis relies on the accurate knowledge of the geometry, as determined from the qualification model of the electronic box still in the lab. In order to take into account the orbit evolution with time, the dose profile is determined with yearly-averaged orbital parameters for each of the 12 years of measurements. The aim of this analysis is to estimate the possibility of releasing some margins for future projects.

Abstract 19495: Compensatory Strategies Improve Medication Adherence in Heart Failure Patients With Mild Global Cognitive Impairment

Introduction: Mild cognitive impairment is common in patients with HF and is linked to poor medication adherence. Poor medication adherence is associated with higher mortality and hospitalizations. Medication adherence strategies to compensate for cognitive impairment are not well understood. The purpose of this secondary analysis is to identify the type and frequency of compensatory strategies used by patients with HF and mild cognitive impairment and to determine if compensatory strategy use is associated with medication adherence. Methods and Results: The parent study was a longitudinal descriptive study (N=379) to determine the relationships among cognitive impairment and self-management. The Modified Mental Status (3MS), a global measure of cognition and an electronic pill box (Medsignals) were used. A subsample of 156 patients with mild to moderate global cognitive impairment was selected based on a 3MS of less than 90. The frequencies of four compensatory strategies use were: pillbox (n=85, 57%), family reminders (n=17, 11%), reminders including calendars and alarms (n=17, 11%), and combining administration with other tasks (n=51, 33%). An independent samples t-test was performed to test the difference in medication adherence between persons that did and did not use each compensatory strategy. Pillbox use was associated with medication adherence (p<.05). The group that used a pillbox (n=80) had a mean medication adherence of 82.5%, while no pillbox use (n=90) had a mean of 74.8% No other compensatory strategies were related to better medication adherence. Conclusion: In clinical practice, global cognition screening and education on pillbox use to improve medication adherence is recommended. Although other compensatory strategies did not have a significant impact on medication adherence, more research is need to understand compensatory strategies to help patients with mild cognitive impairment improve medication adherence.

Combined convective heat and airborne pollutant removals in a slot vented enclosure under different flow schemes: Parametric investigations and non unique flow solutions

This paper reports a numerical study of mixed convection on a heated and polluted strip within a slot ventilated enclosure in which the displacement and mixing flow schemes are considered. Contours of streamfunction, heatfunction, and massfunction are presented to clearly scrutinize the mechanism of heat and airborne pollutant transports. For the displacement flow scheme, thermal Nusselt and pollutant Sherwood numbers under different Reynolds numbers remain almost constant as the value of Gr/Re2 decreases down to the regime of forced convection dominated. However, as Ar increases up to the regime of natural convection dominated, both Nu and Sh increase sharply with Ar (Gr/Re2). Similar trends could be observed for the situation of mixing ventilated flow scheme. In the mixing scheme, non unique steady flow solutions could be observed for the range of transitional flow regime. Upward solutions, downward solutions and rest solutions have been exemplified with varying Gr/Re2. Dual solution branches could be sustained at the range of 39.0 ≤ Gr/Re2 ≤ 6.0 × 103, while the rest solutions obtained from rest states were completely coinciding with former continuous solutions. The present work could be significant for the natural optimization and passive control of heat and pollutant removals from the electronic boxes or building enclosures.

Moving Beyond Directly Observed Therapy for Tuberculosis.

Moving Beyond Directly Observed Therapy for Tuberculosis.

Entropy production in a non-Markovian environment.

Stochastic thermodynamics and the associated fluctuation relations provide the means to extend the fundamental laws of thermodynamics to small scales and systems out of equilibrium. The fluctuating thermodynamic variables are usually treated in the context of either isolated Hamiltonian evolution, or Markovian dynamics in open systems. However, there is no reason a priori why the Markovian approximation should be valid in driven systems under nonequilibrium conditions. In this work, we introduce an explicitly non-Markovian model of dynamics of an open system, where the correlations between the system and the environment drive a subset of the environment out of equilibrium. Such an environment gives rise to a new type of non-Markovian entropy production term. Such non-Markovian components must be taken into account in order to recover the fluctuation relations for entropy. As a concrete example, we explicitly derive such modified fluctuation relations for the case of an overheated single electron box.

Energy and temperature fluctuations in the single electron box

In mesoscopic and nanoscale systems at low temperatures, charge carriers are typically not in thermal equilibrium with the surrounding lattice. The resulting, non-equilibrium dynamics of electrons has only begun to be explored. Experimentally the time-dependence of the electron temperature (deviating from the lattice temperature) has been investigated in small metallic islands. Motivated by these experiments, we investigate theoretically the electronic energy and temperature fluctuations in a metallic island in the Coulomb blockade regime, tunnel coupled to an electronic reservoir, i.e. a single electron box. We show that electronic quantum tunnelling between the island and the reservoir, in the absence of any net charge or energy transport, induces fluctuations of the island electron temperature. The full distribution of the energy transfer as well as the island temperature is derived within the framework of full counting statistics. In particular, the low-frequency temperature fluctuations are analysed, fully accounting for charging effects and non-zero reservoir temperature. The experimental requirements for measuring the predicted temperature fluctuations are discussed.

Megacam: A Wide-Field CCD Imager for the MMT and Magellan

Megacam is a large-format optical camera that can be operated at the f/5 Cassegrain foci of the MMT on Mount Hopkins, Arizona, and the Magellan Clay telescope at Las Campanas Observatory, Chile. Megacam’s focal plane is composed of 36 closely packed e2v CCD42-90 CCDs, each with 2048 × 4608 pixels, assembled in an 18,432 × 18,432 array. Two additional CCD42-90s are provided for autoguiding and focus control. The CCDs have 13.5 μm square pixels that subtend at the f/5 foci, yielding a 25′ × 25′ field-of-view. The camera system includes a focal plane shutter, two filter wheels, two liquid nitrogen reservoirs, a central chamber that holds the CCD mosaic array, and two electronics boxes. Megacam is equipped with a variety of broadband and narrowband filters. Software features include automatic calculation of twilight flat exposure times.

Global Catastrophes: A Very Short Introduction (2nd edition) by Bill McGuire. Oxford University Press, Oxford, 2014. No. of pages: xxv + 123. Price: UK£7.99. ISBN 978‐0‐19‐871593‐1 (paperback)

Book reviewing makes my commuting more pleasurable and productive, but I must have been an eccentric sight with this book in my hand. The average Dutch commuter is reading the Amsterdam Metro, staring into space or pressing buttons on an electronic box of tricks. And in contrast, the big guy with the floppy hat has his nose glued to a book called Global Catastrophes. Did Ajax loose again? Glued is the right word. Bill McGuire's style of writing drew this reader in and kept me enthralled. All of McGuire's catastrophes are of interest to the Earth scientist sensu lato, being either climatic (global warming, Ice Ages), tectonic (super-eruptions, tsunamis and major earthquakes) or extra-terrestrial in origin (bolide impacts). These are subjects that all of us know something about, but perhaps not enough. McGuire does a first class job of providing solid data, and drawing on many and diverse sources of information, such as the evidence from human DNA of the effect of the Toba super-eruption 74 000 years ago on our species (p. 69). Discussion in all areas is educating, entertaining and, perhaps, will cause the reader to look over their shoulder. As always in this series of books, the production complements the excellence of the writing. Illustrations are of good quality and adequate in number. Errors are few, but I was tickled to read of a storm travelling at ‘300 km per second’ (p. 12) – the proof reader was definitely nodding. And any author who quotes Oliver Postgate will get my attention. The list of further reading and index are both adequate. I'm surprised to have missed the first edition of Global Catastrophes, particularly as I like to lurk near the carousel of books in the ‘Very Short Introduction’ series when visiting bookshops, but am delighted to have made the acquaintance of this new incarnation. That it provides food for thought is an understatement. Few Earth scientists would not benefit reading this book and will enjoy it at the same time. It would be an ideal volume for an advanced seminar course, being affordable, readable and thought-provoking.

A Passive, Adaptive and Autonomous Gas Gap heat Switch

We report on the development of a heat switch for autonomous temperature control of electronic components in a satellite. A heat switch can modulate when needed between roles of a good thermal conductor and a good thermal insulator. Electronic boxes on a satellite should be maintained within a typical optimum temperature range of 260 to 310K. The heat sinking is usually by means of a radiator. When the operating temperature of the electronic box increases beyond 310K, a good contact to the radiator is desired for maximum cooling. On the other hand, when the satellite is in a cold dormant state, the electronics box should be heated by the onboard batteries. In this state a weak thermal contact is desired between the electronic box and the heat sink. In the present study, we are developing a gas gap heat switch in which the sorber material is thermally anchored to the electronic box. A temperature change of the electronic box triggers the (de-)sorption of gas from the sorber material and subsequently the gas pressure in the gas gap. This paper describes the physical principles and the current status of this technology. This approach can be extended to cryogenic temperature range.

Effect of Process Parameters on Roughness and Hardness of Surface and Dimensional Accuracy of Lost Wax Process Casting

We know different casting processes like sand casting, gravity die casting, low pressure die casting, pressure die casting, counter pressure die casting, and centrifugal casting, spin casting, lost wax and lost foam casting. But lost wax or lost foam casting process are going to be most acceptable way of castings to get the intricate and complex shaped castings. Lost wax process is generally known as “Investment casting process”. About 5000 years ago the Egyptians used this process in the time of Pharaohs to make gold jewellery, which was the way of their investment hence the names comes. Ancient “lost wax process” domination for producing beautiful sculptures turns into a present day near net shape manufacturing of intricate engineering components. The journey begins with the development of Investment casting process by Dr. William H. Taggart of Chicago who wrote a detailed study on Investment casting process in 1907. Today’s Investment casting is a versatile process. It is used to manufacture parts ranging from turbocharger wheels to golf stick heads, from electronic boxes to hip replacement implants, General engineering to aerospace, automobiles to pump industries particularly impellers. In this paper we are discussing about the key parameters of the investment casting process which will give a more dimensional accuracy and best surface smoothness and hardness for the mold. The pre-conditions for the mold are discussed and possible defects can occur in the mold and the rectification also analysed experimentally.

A method for sampling microbial aerosols using high altitude balloons

Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~2.7kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035m3 per km of altitude sampled. Based on quality control measurements, the collection of ~100cells rod−1 provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere.

The Search-Coil Magnetometer for MMS

Abstract The tri-axial search-coil magnetometer (SCM) belongs to the FIELDS instrumentation suite on the Magnetospheric Multiscale (MMS) mission (Torbert et al. in Space Sci. Rev. (2014), this issue). It provides the three magnetic components of the waves from 1 Hz to 6 kHz in particular in the key regions of the Earth’s magnetosphere namely the subsolar region and the magnetotail. Magnetospheric plasmas being collisionless, such a measurement is crucial as the electromagnetic waves are thought to provide a way to ensure the conversion from magnetic to thermal and kinetic energies allowing local or global reconfigurations of the Earth’s magnetic field. The analog waveforms provided by the SCM are digitized and processed inside the digital signal processor (DSP), within the Central Electronics Box (CEB), together with the electric field data provided by the spin-plane double probe (SDP) and the axial double probe (ADP). On-board calibration signal provided by DSP allows the verification of the SCM transfer function once per orbit. Magnetic waveforms and on-board spectra computed by DSP are available at different time resolution depending on the selected mode. The SCM design is described in details as well as the different steps of the ground and in-flight calibrations.

Experimental realization of a Szilard engine with a single electron.

The most succinct manifestation of the second law of thermodynamics is the limitation imposed by the Landauer principle on the amount of heat a Maxwell demon (MD) can convert into free energy per single bit of information obtained in a measurement. We propose and realize an electronic MD based on a single-electron box operated as a Szilard engine, where kBT ln 2 of heat is extracted from the reservoir at temperature T per one bit of created information. The information is encoded in the position of an extra electron in the box.

Debris area distribution of spacecraft under hypervelocity impact

Cross-sectional area is an important parameter for spacecraft breakup debris as it is the directly measured data in space observation. It is significant for observing and analysing the spacecraft breakup event to accurately modelling the area distribution of the breakup debris. In this paper, experimental study has been performed on debris area distribution characteristics of spacecraft under hypervelocity impact. The tests are carried out at the ballistic ranges of CARDC. Aluminium projectiles are launched to normally impact the simulated spacecrafts at about 3.0km/s. The simulated spacecrafts are made up of aluminium plates, filled with some simulated electronics boxes, each of which was installed with a circuit board. “Soft-catch” devices are used to recover the breakup fragments. The test results show that: 1) the relationship between the cross-sectional area and the characteristic length of debris, which can be obtained in the logarithmic coordinates by linear fitting, represents the debris shape characteristic in a certain extent; 2) the area-to-mass ratios of fragments show normal distributions in the logarithmic coordinates; 3) debris made of different materials can be distinguished by different peaks on the distribution curves; 4) the area-to-mass ratio distributions can be expressed by a linear superimposition of several normal functions which represent the main materials of the spacecraft.

Experimental observation of the role of mutual information in the nonequilibrium dynamics of a Maxwell demon.

We validate experimentally a fluctuation relation known as generalized Jarzynski equality governing the work distribution in a feedback-controlled system. The feedback control is performed on a single electron box analogously to the original Szilard engine. In the generalized Jarzynski equality, mutual information is treated on an equal footing with the thermodynamic work. Our measurements provide the first evidence of the role of mutual information in the fluctuation theorem and thermodynamics of irreversible processes.