Gas Discharge Lamps Are Volatile Memristors

Discharge lamps can be classified as high-pressure and low-pressure lamps, which operate under different scientific principles. They have exhibited the well-known fingerprints of memristors. This paper describes the mathematical models of both of high- and low-pressure discharge lamps based on their respective physical nature and behaviors, and then explains how these models can be unified into a generalized mathematical framework that confirms their memristor characteristics. Practical and theoretical results from high-pressure and low-pressure lamps are included to illustrate their 3 fingerprints of the memristor characteristics. The results indicate that gas discharge lamps are not ideal but volatile memristors.published_or_final_versio

On Local Activity and Edge of Chaos in a NaMLab Memristor

Local activity is the capability of a system to amplify infinitesimal fluctuations in energy. Complex phenomena, including the generation of action potentials in neuronal axon membranes, may never emerge in an open system unless some of its constitutive elements operate in a locally active regime. As a result, the recent discovery of solid-state volatile memory devices, which, biased through appropriate DC sources, may enter a local activity domain, and, most importantly, the associated stable yet excitable subdomain, referred to as edge of chaos, which is where the seed of complexity is actually planted, is of great appeal to the neuromorphic engineering community. This paper applies fundamentals from the theory of local activity to an accurate model of a niobium oxide volatile resistance switching memory to derive the conditions necessary to bias the device in the local activity regime. This allows to partition the entire design parameter space into three domains, where the threshold switch is locally passive (LP), locally active but unstable, and both locally active and stable, respectively. The final part of the article is devoted to point out the extent by which the response of the volatile memristor to quasistatic excitations may differ from its dynamics under DC stress. Reporting experimental measurements, which validate the theoretical predictions, this work clearly demonstrates how invaluable is non-linear system theory for the acquirement of a comprehensive picture of the dynamics of highly non-linear devices, which is an essential prerequisite for a conscious and systematic approach to the design of robust neuromorphic electronics. Given that, as recently proved, the potassium and sodium ion channels in biological axon membranes are locally active memristors, the physical realization of novel artificial neural networks, capable to reproduce the functionalities of the human brainmore closely than state-of-the-art purely CMOS hardware architectures, should not leave aside the adoption of resistance switching memories, which, under the appropriate provision of energy, are capable to amplify the small signal, such as the niobium dioxide micro-scale device fromNaMLab, chosen as object of theoretical and experimental study in this work

A ferroelectric memristor

Memristors are continuously tunable resistors that emulate synapses. Conceptualized in the 1970s, they traditionally operate by voltage-induced displacements of matter, but the mechanism remains controversial. Purely electronic memristors have recently emerged based on well-established physical phenomena with albeit modest resistance changes. Here we demonstrate that voltage-controlled domain configurations in ferroelectric tunnel barriers yield memristive behaviour with resistance variations exceeding two orders of magnitude and a 10 ns operation speed. Using models of ferroelectric-domain nucleation and growth we explain the quasi-continuous resistance variations and derive a simple analytical expression for the memristive effect. Our results suggest new opportunities for ferroelectrics as the hardware basis of future neuromorphic computational architectures

Power-efficient silicon nitride thermo-optic phase shifters for visible light

We demonstrate power-efficient, thermo-optic, silicon nitride waveguide phase shifters for blue, green, and yellow wavelengths. The phase shifters operated with low power consumption due to a suspended structure and multi-pass waveguide design. The devices were fabricated on 200-mm silicon wafers using deep ultraviolet lithography as part of an active visible-light integrated photonics platform. The measured power consumption to achieve a π phase shift (averaged over multiple devices) was 0.78, 0.93, 1.09, and 1.20 mW at wavelengths of 445, 488, 532, and 561 nm, respectively. The phase shifters were integrated into Mach-Zehnder interferometer switches, and 10 − 90% rise(fall) times of about 570(590) μs were measured

Influence of Maternal Infection and Pregnancy Complications on Cord Blood Telomere Length

BACKGROUND: Exposure to suboptimal intrauterine environment might induce structural and functional changes that can affect neonatal health. Telomere length as an important indicator of cellular health has been associated with increased risk for disease development. OBJECTIVES: This study was aimed to examine the independent and combined effects of maternal, obstetric, and foetal factors on cord blood telomere length (TL). METHODS: Pregnant women at the gestational age of 20th to 24th week who attended the antenatal clinic of a major local hospital in Hong Kong were recruited. Participants were asked to complete a questionnaire on demographics, health-related quality of life, and history of risk behaviors. Medical history including pregnancy complications and neonatal outcomes was obtained from electronic medical records of both mother and neonate. Umbilical cord blood was collected at delivery for TL determination. RESULTS: A total of 753 pregnant women (average age: 32:18 ± 4:51 years) were recruited. The prevalence of maternal infection, anaemia, and hypertension during pregnancy was 30.8%, 30.0%, and 6.0%, respectively. The adjusted regression model displayed that maternal infection was negatively associated with cord blood TL (β = −0:18, p = 0:026). This association became even stronger in the presence of antenatal anaemia, hypertension, delivery complications, or neonatal jaundice (β = −0:25 to −0.45). Conclusions. This study consolidates evidence on the impact of adverse intrauterine environment at the cellular level. Maternal infection was significantly associated with shorter cord blood TL in a unique manner such that its presence may critically determine the susceptibility of telomere to other factors

Computers from plants we never made. Speculations

We discuss possible designs and prototypes of computing systems that could be based on morphological development of roots, interaction of roots, and analog electrical computation with plants, and plant-derived electronic components. In morphological plant processors data are represented by initial configuration of roots and configurations of sources of attractants and repellents; results of computation are represented by topology of the roots' network. Computation is implemented by the roots following gradients of attractants and repellents, as well as interacting with each other. Problems solvable by plant roots, in principle, include shortest-path, minimum spanning tree, Voronoi diagram, $\alpha$-shapes, convex subdivision of concave polygons. Electrical properties of plants can be modified by loading the plants with functional nanoparticles or coating parts of plants of conductive polymers. Thus, we are in position to make living variable resistors, capacitors, operational amplifiers, multipliers, potentiometers and fixed-function generators. The electrically modified plants can implement summation, integration with respect to time, inversion, multiplication, exponentiation, logarithm, division. Mathematical and engineering problems to be solved can be represented in plant root networks of resistive or reaction elements. Developments in plant-based computing architectures will trigger emergence of a unique community of biologists, electronic engineering and computer scientists working together to produce living electronic devices which future green computers will be made of.Comment: The chapter will be published in "Inspired by Nature. Computing inspired by physics, chemistry and biology. Essays presented to Julian Miller on the occasion of his 60th birthday", Editors: Susan Stepney and Andrew Adamatzky (Springer, 2017

In-game action list segmentation and labeling in real-time strategy games

Data set available at http://ink.library.smu.edu.sg/data/1/</p

Potential use of coconut husk-based magnetic sorbent for defoaming application

Absorption process is the most common method that is being applied to sweeten sour gas in the oil and gas industry. However, this process does have several consequences which will trigger the foam formation of foam that will reduce the mass transfer efficiency and absorption capacity as well as amine solutions carryover to the downstream processes. The removal of undesired contaminants in activated methyldiethanolamine (MDEA) was conducted by utilizing magnetic activated carbon (MAC). In this work, MAC was synthesized from coconut husk through chemical activation and co-precipitation methods. The performance of this material as an adsorbent was evaluated based on the foaming behaviour of activated MDEA solvent after being contacted with MAC at different duration and varying amounts. Nitrogen gas was introduced into the solvent through a gas diffuser to create foam. Based on the results, the foam volume generated by activated MDEA solvent was identified to decrease with the increase in both MAC contact time and amount. The highest removal efficiency by MAC was identified to be at 1 h contact time between MAC and activated MDEA solvent where the foam breaking time was reduced to 10–30 min. Meanwhile, the addition of 50 % MAC into the solvent was able to further decrease the foam breaking time to 5–10 min. The characteristics of the prepared MAC were evaluated through various instrumental analyses. This study shows that the MAC synthesized from coconut husk has a good potential as an adsorbent in removing the contaminants in activated MDEA solvent to reduce foam formation

Potential use of coconut husk-based magnetic sorbent for defoaming application

Absorption process is the most common method that is being applied to sweeten sour gas in the oil and gas industry. However, this process does have several consequences which will trigger the foam formation of foam that will reduce the mass transfer efficiency and absorption capacity as well as amine solutions carryover to the downstream processes. The removal of undesired contaminants in activated methyldiethanolamine (MDEA) was conducted by utilizing magnetic activated carbon (MAC). In this work, MAC was synthesized from coconut husk through chemical activation and co-precipitation methods. The performance of this material as an adsorbent was evaluated based on the foaming behaviour of activated MDEA solvent after being contacted with MAC at different duration and varying amounts. Nitrogen gas was introduced into the solvent through a gas diffuser to create foam. Based on the results, the foam volume generated by activated MDEA solvent was identified to decrease with the increase in both MAC contact time and amount. The highest removal efficiency by MAC was identified to be at 1 h contact time between MAC and activated MDEA solvent where the foam breaking time was reduced to 10–30 min. Meanwhile, the addition of 50 % MAC into the solvent was able to further decrease the foam breaking time to 5–10 min. The characteristics of the prepared MAC were evaluated through various instrumental analyses. This study shows that the MAC synthesized from coconut husk has a good potential as an adsorbent in removing the contaminants in activated MDEA solvent to reduce foam formation