In this paper we present a thermal conductivity gas sensor with improved sensitivity by adding holes in the thin-film membrane. A numerical model is created and validated against the reference CMOS ...MEMS thermal conductivity sensor. The numerical model is used to investigate the advantages of having isolating holes through the membrane, located on either side of the heating resistor. These holes increase robustness and minimise catastrophic failure caused by pressure difference whilst simultaneously increasing sensitivity by enhancing convective interaction. The electro-thermal efficiency is shown to increase by 16% whilst the sensitivity to measuring percentage CO 2 increases by 39.2%. It is also shown that increasing the width of the holes does not have significant effect on these sensitivities; thus, small holes can be incorporated, leaving room for multiple resistors across the membrane for different measuring techniques. This paper serves as proof that membrane holes can be used to optimise thermal conductivity sensors and will serve as a reference when these designs are fabricated and tested, leading to a new low-power, high-sensitivity gas sensor.
Recently, the interest in electrocardiogram (ECG) signal analysis has grown, as it has been seen as a saddle point in diagnosing cardiovascular disease. The ECG is a standard noninvasive method for ...diagnostic and routine monitoring of the heart. Neural networks were used for automatic disease identification. In this context, the main subject of this article is the classification of ECG signals for the identification of heart functioning problems. Secondarily, we analyze how different acquisition frequencies of the ECG signals lead to variation in neural networks performance. To this end, two data sets containing ECG signals were used: PTB and PTB-XL. Four neural networks architectures were compared in terms of performance: the first and the second are based on convolutional neural networks and the third and fourth are derived from the first two, by adding a new branch containing nonlinear features extracted from the ECG signals. On the PTB database, the best results were obtained with a convolutional neural network with feature injection, with an accuracy of 89.012% for 100 Hz acquired signals. The best results for PTB- XL were obtained with the same network with an accuracy of 85.111% and 100 Hz.
There has been an increasing interest in on-orbit autonomous servicing and repair of satellites as well as controlled active debris removal (ADR) in the space industry recently. One of the most ...challenging tasks for servicing/repair as well as for ADR is the rendezvous and docking with a non-cooperative tumbling resident space object (RSO). This paper presents a propellant optimal maneuver profile for a servicing spacecraft to perform proximity operations and eventually dock with a non-cooperative target. The strategy is to find an optimal trajectory which will guide the servicing spacecraft to approach the tumbling satellite such that the two vehicles will eventually have no relative motion. Therefore, a subsequent docking or capture operation can be safely performed. The research described here elaborates on the previous work that studied the minimum-control-effort for a 3-D docking to a tumbling object considering a full six-degree-of-freedom model of both chaser and target. The current work expands the scope by adding new set of linearized equations of motion that capture the effect of the J 2 geopotential disturbance force. Typically, Hill's linearized equation of relative motion have been used for this analysis, but they fail to capture the effect of J 2 disturbance force on the chaser satellite. Firstly, the effects of the J 2 disturbance force is added to the linearized equations of motion by the addition of the J 2 terms. Secondly, minimum-control-effort optimality condition is examined and propellant optimal trajectories for a relative motion problem are then numerically solved, by using a direct collocation method based on the Gauss pseudospectral approach. The simulation results shows the effect of errors caused by the oblateness of the earth (as described by the J 2 potential) on the described relative motion problem. Furthermore, effect of J 2 disturbance on the optimal trajectory is discussed for the minimum propellant-consumption optimality condition.
Novel phthalimide derivatives, namely N-(1,3-dioxoisoindolin-2-yl)-2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetamide (1a) and N-(1,3-dioxoisoindolin-2-yl)thiophene-2-carboxamide (1b), and ...hexahydrophthalimide derivative N-(1,3-dioxohexahydro-1H-isoindol-2(3H)-yl)-2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetamide (2), have been synthesized. The phthalimide derivatives were synthesized from phthalic anhydride and 2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetohydrazide or thiophene-2-carbohydrazide, and the hexahydrophthalimide derivative has been synthesized from hexahydrophthalic anhydride and 2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetohydrazide. The chemical structures of the compounds are elucidated by Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectra. The new in vitro antioxidant activities of the obtained substances were evaluated using the DPPH method. All tested compounds showed antioxidative activity, the most active compound being 1b. Bioinformatics tools were used for the prediction of pharmacokinetics and pharmacodynamics profiles. Our results showedthat all compounds have a suitable intestinal absorption rate, good BBB and CNS permeabilities and have as molecular targets MAO B, COX-2 and NF-KB, important for antioxidant activities.
The process of nanoparticles production by nanosecond pulsed laser ablation of aluminum targets situated in deionized water was studied from the point of view of laser–target interaction and incident ...laser fluence domain selection as a preliminary stage in the process of nanoparticles production. We have analyzed the irradiated surface morphology and crater profiles as a function of irradiation conditions (incident fluence and irradiation pulses number) by optical microscopy and white light interferometry in order to determine the most efficient coupling between the irradiation conditions and the irradiated surface immersed in liquid. The obtained nanoparticles were studied “in situ”, as obtained in suspension in water and “ex situ”, using TEM. TEM analyses have demonstrated that we have obtained nanoparticles with the lowest dimensions of 3–5nm organized in clouds with dimensions between 40 and 80nm. Typically the obtained nanoparticles presented two clear distributions, one corresponding to low diameters in the 6–10 or 20–40nm regions, and another with a distribution around a maximum situated at hundreds of nanometers (250–290nm). The obtained nanoparticles distribution was correlated with the irradiation conditions.
•NP Al production by LAL at 355nm, 6ns pulses, in the (10–35)J/cm2 fluencies domain.•The irradiation conditions were selected after the irradiation print was analyzed.•TEM and DNS were used to measure the Al NP dimensions situated in the 3–400nm.
The widespread use of insulating oils (transformer oils) having mineral origin, because of their toxic organic substances and xenobiotic, poses a serious risk to the environment. Synthetic ester ...oils, although limited risk to the environment, its use is limited due to their relatively high price. This paper presents the preliminary results of the studies of the possible use of the natural ester oils of vegetable origin in the electrical equipment.
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Background: An overall survival (OS) benefit in WT KRAS exon 2 mCRC was not seen with pmab monotherapy in study 20020408 possibly due to crossover of patients (pts) in the BSC arm. ...Retrospective analyses have indicated that other KRAS and NRAS mutations beyond KRAS exon 2 are predictive of anti-EGFR tx effects. Study 20100007 assesses the OS benefit of pmab in chemorefractory WT KRAS exon 2 mCRC and is the first phase 3 trial to prospectively evaluate pmab tx effects in WT RAS (exons 2, 3, and 4 of KRAS and NRAS) mCRC. Methods: Anti-EGFR naive pts were randomized 1:1 to receive pmab (6 mg/kg Q2W) + BSC or BSC. KRAS exon 2 and RAS mutation status of tumors were determined centrally. The primary endpoint was OS in WT KRAS exon 2 mCRC. Secondary endpoints were OS in WT RAS mCRC and progression-free survival (PFS), objective response rate (ORR), and safety in both WT KRAS exon 2 and WT RAS groups. Crossover was not permitted. Results: 377 pts with WT KRAS exon 2 mCRC were enrolled. RAS ascertainment rate was 86%. OS was significantly improved with pmab + BSC vs BSC in both WT KRAS exon 2 (HR=0.73, 95% CI=0.57-0.93, P=0.0096) and WT RAS (HR=0.70, 95% CI=0.53-0.93, P=0.0135) mCRC (results in table). Pts with mutant RAS mCRC did not benefit from pmab tx (OS HR=0.99, 95% CI=0.49-2.00). No new safety signals were seen. Conclusions: Pmabsignificantly improved OS in chemorefractory WT KRAS exon 2 mCRC. The tx effects in OS and PFS were more pronounced in those with WT RAS mCRC, further substantiating the importance of RAS testing at diagnosis to best inform the use of pmab to treat mCRC. Clinical trial information: NCT01412957. Table: see text
This article proposes a silicon-on-insulator complementary metal-oxide semiconductor (CMOS) micro-electromechanical system (MEMS) thin-film pressure sensor in which the sensing elements are based on ...stress-sensitive MOSFETs, and the carrier mobility and channel resistance vary with applied pressure. Four MOSFETs are embedded within a silicon dioxide membrane to form a Wheatstone bridge. The sensors are fabricated in a commercial foundry with p-channel and n-channel designs both investigated. The fabricated pMOSFET design gave a pressure sensitivity of 5.21 mV/kPa, whereas the nMOSFET gave about half the sensitivity at 2.40 mV/kPa. This shows a highly sensitive pressure sensor, with improved sensitivity on traditional piezoresistors, as well as significantly higher sensitivity than current MOSFET based pressure sensors. Moreover, the maximum dc power consumption was only 190 and 390 μ W for the pMOSFET and nMOSFET, respectively. This low-cost, low-power, high-sensitivity CMOS MEMS technology with on-chip electronics could be used toward the implementation of MOSFET-based pressure transduction in a multitude of industrial and other applications.
The \(G^{+}\) method is a new method, a powerful one, for the study of (homogeneous and nonhomogeneous) products of nonnegative matrices -- for problems on the products of nonnegative matrices. To ...study such products, new classes of matrices are introduced: that of the sum-positive matrices, that of the \(\left \Delta \right \)-positive matrices on partitions (of the column index sets), that of the \(g_{k}^{+}\)-matrices... On the other hand, the \(g_{k}^{+}\)-matrices lead to necessary and sufficient conditions for the \(k\)-connected graphs. Using the \(G^{+}\) method, we prove old and new results (Wielandt Theorem and a generalization of it, etc.) on the products of nonnegative matrices -- mainly, sum-positive, \(\left \Delta \right \)-positive on partitions, irreducible, primitive, reducible, fully indecomposable, scrambling, or Sarymsakov matrices, in some cases the matrices being, moreover, \(g_{k}^{+}\)-matrices (not only irreducible).
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