2,095 research outputs found
State-homomorphisms on -algebras
No full textsummary:Riečan [12] and Chovanec [1] investigated states in -algebras. Earlier, Riečan [11] had dealt with analogous ideas in -posets. In the monograph of Riečan and Neubrunn [13] (Chapter 9) the notion of state is applied in the theory of probability on -algebras. We remark that a different definition of a state in an -algebra has been applied by Mundici [9], [10] (namely, the condition (iii) from Definition 1.1 above was not included in his definition of a state; in other words, only finite additivity was assumed). Below we work with the definition from [13]; but, in order to avoid terminological problems we use the term “state-homomorphism” (instead of “state”). The author is indebted to the referee for his suggestion concerning terminology. Let be an -algebra which is defined on a set with . In the present paper we show that there exists a one-to-one correspondence between the system of all state-homomorphisms on and the system of all -closed maximal ideals of . For -algebras we apply the notation and the definitions as in Gluschankof [3]. The relations between -algebras and abelian lattice ordered groups (cf. Mundici [8]) are substantially used in the present paper
A 60 mV Input Voltage, Process Tolerant Start-Up System for Thermoelectric Energy Harvesting
No full textThis paper presents a 60 mV input voltage start-up system for thermoelectric energy harvesting. A new process tolerant inverter cell is proposed, which is functional at supply voltages as low as 60 mV. Using the proposed unit cell, a ring oscillator has been implemented. The ring oscillator is followed by 40 charge-pump stages, an ultra-low-power level detector, and a boost converter. The energy harvesting system can generate an output voltage of 1 V and delivers a maximum power of 4.5 μW from a 60 mV supply. This system has been implemented in a standard 0.18 μm CMOS technology, uses neither zerothreshold voltage (normally-on) negative-channel metal-oxide semiconductor nor microelectromechanical systems switches and occupies 3.3 mm2.Accepted author manuscriptBio-Electronic
On some properties of quasi-MV algebras and √′ quasi-MV algebras. Part II
No full textThe present paper is a sequel to Paoli F, Ledda A, Giuntini R, Freytes H (On some properties of QMV algebras and √′ QMV algebras, submitted). We provide two representation results for quasi-MV algebras in terms of MV algebras enriched with additional structure; we investigate the lattices of subvarieties and subquasivarieties of quasi-MV algebras; we show that quasi-MV algebras, as well as cartesian and flat √′ quasi-MV algebras, have the amalgamation property. © Springer-Verlag 2007.We gratefully acknowledge the precious information and insights we gathered from conversations or e-mail exchanges with Roberto Giuntini and Danica Jakubikova-Studenovska. We are especially indebted to Matthew Spinks for his extensive and detailed comments on a preliminary draft of the paper. The first author is partially supported by Grants MTM2004-03101 and TIN2004-07933-C03-02 from the Spanish Ministerio de Educación y Ciencia and Grant 2001SGR-00017 from the Generalitat de CatalunyaPeer Reviewe
Measles virus causes immunogenic cell death in human melanoma
No full textNoOncolytic viruses (OV) are promising treatments for cancer, with several currently undergoing testing in randomised clinical trials. Measles virus (MV) has not yet been tested in models of human melanoma. This study demonstrates the efficacy of MV against human melanoma. It is increasingly recognised that an essential component of therapy with OV is the recruitment of host antitumour immune responses, both innate and adaptive. MV-mediated melanoma cell death is an inflammatory process, causing the release of inflammatory cytokines including type-1 interferons and the potent danger signal HMGB1. Here, using human in vitro models, we demonstrate that MV enhances innate antitumour activity, and that MV-mediated melanoma cell death is capable of stimulating a melanoma-specific adaptive immune response
A 10-mV-Startup-Voltage Thermoelectric Energy Harvesting System With a Piezoelectric Starter
No full textAn ultra-low-startup-voltage thermoelectric energy harvesting system assisted by a piezoelectric generator (PEG) is presented in this paper. When the energy harvesting system is implemented in a place where there is mechanical vibration, the associated PEG can generate a stable clock signal and drive the boost converter to start from the cold state even at extremely low thermoelectric generator (TEG) voltage. The proposed system is designed and simulated in a 180-nm BCD process. The simulations show that the proposed system can start the TEG system from the cold state from as low as 10 mV of TEG voltage while keeping a 63.9% efficiency. The peak power conversion efficiency is achieved at 74.9% when the TEG voltage is 50 mV.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Instrumentatio
A PV-assisted 10-mV Startup Boost Converter for Thermoelectric Energy Harvesting
No full textThis paper presents a boost converter for thermo-electric energy harvesting with photovoltaic (PV)-assisted startup. The converter employs a new two-phase startup architecture and the PV cell is used in the first phase to provide an initial high voltage for startup. This high voltage drives the boost converter to charge a startup capacitor, which powers the main control block to continue self-startup in phase 2. The proposed system is designed and simulated in a BCD process. The simulations show successful cold-start from 10 mV thermoelectric voltage. In addition, maximum power point tracking and zero current switching techniques are adopted in the system to achieve 91% peak efficiency. The proposed system can finish the cold-start within 250 ms.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Instrumentatio
Voltage control in MV distribution networks with a large share of distributed renewable generation
No full textTraditionally, voltage control in MV distribution networks has been focused on dealing with voltage drop along radially operated feeders. The actual implemented controllers use local voltage measurements and have been designed and calibrated for a passive and radial use of the MV system. The presence of distributed renewable generation (DRG) makes these assumptions no longer valid. The power generated by DRG units will increase the voltage at adjacent nodes and even cause it to be higher than the voltage at the primary substation. Consequently, the presence of DRG will affect voltage control in distribution systems and it needs to be reconsidered whether methods like local voltage control and reactive power injection can still enable the network operator to cope with the newly introduced voltage rise issues. The aim of this study is to create a new voltage control strategy, which will not only successfully limit voltage variations, but also allow for an increased penetration of DRG. The proposed coordinated voltage control strategy deploys control of HV/MV transformers On-Load Tap Changers in combination with active power control provided by Intelligent Nodes, that allows network reconfiguration. The Cigré MV distribution network benchmark is used as a basis for the test system, while appropriate models for the PV Power Plants, the Wind Power Plants and the Intelligent Nodes were developed. In order to draw realistic simulation results, a summer / winter seasonal variation is featured. The proposed voltage control algorithm is incrementally developed, allowing for the identification of factors hindering the controller performance and the development of a control algorithm which is more targeted towards dealing with specific issues. The commercial power system simulation software DIgSILENT PowerFactory 15.0 is used for carrying out these simulations. The analysis of simulation results shows that the proposed voltage control strategy is capable of facilitating the transition towards active MV distribution networks, by offering considerably higher DRG penetration levels and strictly bound network voltages. The modelled controller is particularly applicable to MV distribution networks across North Europe. Among others, the limiting factors for an increased DRG penetration are identified, along with the effects that the reactive power control and the choice of voltage limits have. Finally, recommendations for future research are provided.Sustainable Energy TechnologyChemical EngineeringApplied Science
Design and prototyping of an ECG simulator for medical device testing in low-resource settings
No full textEnsuring reliable and safe performance of medical devices in healthcare institutions is crucial for the wellbeing of patients. For this, physiological simulators may be used, which provide reference signals to compare against. The usage of physiological simulators, such as ECG simulators, as medical device testers is widely extended in high-income countries. However, their high cost and need for frequent calibration by the manufacturer make their availability and usage in low-resource settings (LRs) unfeasible. Remote healthcare facilities, low- and middle-income countries (LMICs), and hospitals in general would highly benefit from new designs of simulators that can be produced, repaired and maintained locally. Therefore, we present the design of an affordable, portable Arduino UNO-based prototype ECG simulator with the novel feature of visual indicators for self-calibration checks. The ECG simulator was built with affordable and broadly available components and tools, retrieved from an educational electronics workshop. The current prototype can be used to test 3-lead ECG meters. It reproduces a lead II waveform extracted from MIT-BIH database, with 1.3 mV peak-to-peak and 0.1 mV negative offset. Heart rage simulation ranges from 35 to 130 bpm, in steps of 5 bpm. Signal data points defining a desired waveform and heart rate can be uploaded into the simulator via the user-friendly and open-source Arduino software. The simulator could also be modified to generate 10- or 12-leads by upscaling the electronics and adding more storage space. Analog signal generation is based on a pulse-width modulation signal, which is smoothened by a low-pass filter and decreased in amplitude with operational amplifiers, which also add a negative voltage offset. Visual indicators enable simulated frequency and amplitude checks without the need of external tools, while amplitude can be calibrated manually. Additionally, rechargeable batteries facilitate on-site testing of medical equipment. Evaluation of the prototype included performance and functionality tests. HR and amplitude accuracy of the simulated signal were quantified and compared to those from a commercial simulator. Lastly, the performance of the simulator in a real scenario was tested at the Green Pastures Hospital of Pokhara, Nepal. Functionality tests proved the correct detection of the simulated signal by 6 patient monitors of different models, manufacturers and purchase year.Biomedical Engineerin
Chitosan/Albumin Coating Factorial Optimization of Alginate/Dextran Sulfate Cores for Oral Delivery of Insulin
No full textThe design of nanoparticle formulations composed of biopolymers, that govern the physicochemical properties of orally delivered insulin, relies on improving insulin stability and absorption through the intestinal mucosa while protecting it from harsh conditions in the gastrointestinal (GI) tract. Chitosan/polyethylene glycol (PEG) and albumin coating of alginate/dextran sulfate hydrogel cores are presented as a multilayer complex protecting insulin within the nanoparticle. This study aims to optimize a nanoparticle formulation by assessing the relationship between design parameters and experimental data using response surface methodology through a 3-factor 3-level optimization Box–Behnken design. While the selected independent variables were the concentrations of PEG, chitosan and albumin, the dependent variables were particle size, polydispersity index (PDI), zeta potential, and insulin release. Experimental results showed a nanoparticle size ranging from 313 to 585 nm, with PDI from 0.17 to 0.39 and zeta potential ranging from −29 to −44 mV. Insulin bioactivity was maintained in simulated GI media with over 45% cumulative release after 180 min in a simulated intestinal medium. Based on the experimental responses and according to the criteria of desirability on the experimental region’s constraints, solutions of 0.03% PEG, 0.047% chitosan and 1.20% albumin provide an optimum nanoparticle formulation for insulin oral delivery
MV-algebras, semirings and their applications
No full text2019 - 2020The thesis is divided in two parts: the first part regards MV-semirings,
involutive semirings and semimodules over them with particular attention
to injective and projective semimodules; the second part of the thesis is focused
on the tropical semiring and has the purpose to characterize the sets
which arise as images of retractions that are nonexpansive with respect to a
hemi-norm which plays a key role in tropical geometry.
Semirings and semimodules, and their applications, arise in various branches
of Mathematics, Computer Science, Physics, as well as in many other
areas of modern science (see, for instance, [3]). MV-algebras arose in the
literature as the algebraic semantics of ukasiewicz propositional logic, one
of the longest-known many-valued logic. A connection between MV-algebras
and a special category of additively idempotent semirings (called MV-semirings
or ukasiewicz semirings) was rst observed in [1]. On the one hand, every
MV-algebra has two semiring reducts isomorphic to each other by the
involutive unary operation of MV-algebras (see, e.g., [2, Proposition 4.8]);
on the other hand, the category of MV-semirings de ned in [2] is isomorphic
to the one of MV-algebras. The term equivalence between MV-algebras
and MV-semirings allows us to import results and techniques of semiring
and semimodule theory in the study of MV-algebras as well to use properties
and theorems regarding MV-algebras in the study of semimodules over
MV-semirings.
Indeed, as the theory of modules is an essential chapter of ring theory, so
the theory of semimodules is a crucial aspect in semiring theory and two of
the most important objects in semimodule theory are projective and injective
semimodules.
Although, in general, describing the structure of projective and injective
semimodules seems to be a quite di cult task, we shall give a criterion
for injectivity of semimodules over additively idempotent semirings which
we shall use to describe the structure of injective semimodules over MVsemirings
with an atomic Boolean center, i. e. the boolean elements of the
MV-semiring form an atomic lattice... [edited by Author]XXXIII cicl
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