Micromachined Electric Field Mill Employing a Vertical Moving Shutter

AbstractThis paper presents a new type of micromachined electric field mill (MEFM) for measuring dc electric fields. This MEFM employs thermal actuators for vertical movement of an electrically grounded shutter, to mill the amplitude of a dc electric field incident on underlying sense electrodes. It addresses the main drawbacks of existing MEFMs, which are shutter displacement in large electric field, and drive signal interference from the shutter actuator. Simulation results show that for a 1kV/m dc field the output of the sensor is about 1pA

Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy

In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC) bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application

Thermoelectric Generator Scheme For IOT

In the recent year Thermoelectric Modules (TEM) are widely used for cooling of different electronic devices. Thermoelectric module allows obtaining the additional and dropping of device temperature. The different way for manufacturing array of thermoelectric model by using integrated circuit technology are presented, So the fundamental dependent parameter of the thermoelectric model are thermal conductance, electrical resistance and seebeck coefficient, among the other factors. Paper introduces a method for calculating parameter from observable variables, which can be obtained from temperature, voltage, and electric current measurements made on a working TE device. The parameters are plotted against the temperature between the hot and cold side of the module

Thermodynamic properties of Pt nanoparticles: Size, shape, support, and adsorbate effects

This study presents a systematic investigation of the thermodynamic properties of free and gamma-Al2O3-supported size-controlled Pt nanoparticles (NPs) and their evolution with decreasing NP size. A combination of in situ extended x-ray absorption fine-structure spectroscopy (EXAFS), ex situ transmission electron microscopy (TEM) measurements, and NP shape modeling revealed (i) a cross over from positive to negative thermal expansion with decreasing particle size, (ii) size- and shape-dependent changes in the mean square bond-projected bond-length fluctuations, and (iii) enhanced Debye temperatures (D-circle minus, relative to bulk Pt) with a bimodal size- dependence for NPs in the size range of similar to 0.8-5.4 nm. For large NP sizes (diameter d \u3e 1.5 nm) D-circle minus was found to decrease toward D-circle minus of bulk Pt with increasing NP size. For NPs \u3c = 1 nm, a monotonic decrease of D-circle minus was observed with decreasing NP size and increasing number of low-coordinated surface atoms. Our density functional theory calculations confirm the size- and shape-dependence of the vibrational properties of our smallest NPs and show how their behavior may be tuned by H desorption from the NPs. The experimental results can be partly attributed to thermally induced changes in the coverage of the adsorbate (H-2) used during the EXAFS measurements, bearing in mind that the interaction of the Pt NPs with the stiff, high-melting temperature gamma-Al2O3 support may also play a role. The calculations also provide good qualitative agreement with the trends in the mean square bond-projected bond-length fluctuations measured via EXAFS. Furthermore, they revealed that part of the D-circle minus enhancement observed experimentally for the smallest NPs (d \u3c = 1 nm) might be assigned to the specific sensitivity of EXAFS, which is intrinsically limited to bond-projected bond-length fluctuations

Epigenetic associations of type 2 diabetes and BMI in an Arab population

Background The prevalence of type 2 diabetes (T2D) and obesity has dramatically increased within a few generations, reaching epidemic levels. In addition to genetic risk factors, epigenetic mechanisms triggered by changing environment are investigated for their role in the pathogenesis of these complex diseases. Epigenome-wide association studies (EWASs) have revealed significant associations of T2D, obesity, and BMI with DNA methylation. However, populations from the Middle East, where T2D and obesity rates are highest worldwide, have not been investigated so far. Methods We performed the first EWAS in an Arab population with T2D and BMI and attempted to replicate 47 EWAS associations previously reported in Caucasians. We used the Illumina Infinium HumanMethylation450 BeadChip to quantify DNA methylation in whole blood DNA from 123 subjects of 15 multigenerational families from Qatar. To investigate the effect of differing genetic background and environment on the epigenetic associations, we further assessed the effect of replicated loci in 810 twins from UK. Results Our EWAS suggested a novel association between T2D and cg06721411 (DQX1; p value = 1.18 × 10−9). We replicated in the Qatari population seven CpG associations with BMI (SOCS3, p value = 3.99 × 10−6; SREBF1, p value = 4.33 × 10−5; SBNO2, p value = 5.87 × 10−5; CPT1A, p value = 7.99 × 10−5; PRR5L, p value = 1.85 × 10−4; cg03078551, intergenic region on chromosome 17; p value = 1.00 × 10−3; LY6G6E, p value = 1.10 × 10−3) and one with T2D (TXNIP, p value = 2.46 × 10−5). All the associations were further confirmed in the UK cohort for both BMI and T2D. Meta-analysis increased the significance of the observed associations and revealed strong heterogeneity of the effect sizes (apart from CPT1A), although associations at these loci showed concordant direction in the two populations. Conclusions Our study replicated eight known CpG associations with T2D or BMI in an Arab population. Heterogeneity of the effects at all loci except CPT1A between the Qatari and UK studies suggests that the underlying mechanisms might depend on genetic background and environmental pressure. Our EWAS results provide a basis for comparison with other ethnicities

Phase shifter using defected ground structures with MEMS actuated cavity backing

A MEMS-based control structure consisting of a flexible membrane to actuate ground plane defects is presented. Initial tests were performed with a manually constructed cavity structure placed behind the slot. The cavity depth is increased in discrete intervals and the phase difference determined. Promising results from this experiment led to the application of the membrane itself beneath the ground plane defect. The membrane-backed design allows a continuous generation of phase shift through the variation of the cavity depth. An electrode below the membrane causes a deflection due to an applied electrostatic force, allowing a cavity to form between the membrane and the defect in the ground plane. These cavity-backed designs add negligible loss to the system

Development of carbon dioxide (CO2) sensor for grain quality monitoring

A carbon dioxide sensor was developed using polyaniline boronic acid conducting polymer as the electrically conductive region of the sensor and was demonstrated for use in detecting incipient or ongoing spoilage in stored grain. The developed sensor measured gaseous CO2 levels in the range of 380-2400ppm of CO2 concentration levels. The sensor was evaluated for the influence of temperature (at-25°C to simulate storage and for the operating temperature range of +10°C to +55°C) as well as relative humidity (from 20 to 70%). The variation in the resistance with humidity was curvilinear and repeatable, and had a less pronounced effect on the sensor's performance compared to temperature. The sensor was able to respond to changes in CO2 concentration at various humidity and temperature levels. The response of the PABA film to CO2 concentration was not affected by the presence of alcohols and ketones at 1% of vapour pressure, proving that the developed sensor is not cross-sensitive to these compounds which may be present in spoiling grain. The sensor packaging components were selected and built in such a way as to avoid contamination of the sensing material and the substrate by undesirable components including grain dust and chaff. The developed conducting polymer carbon dioxide sensor exhibited effective response, recovery time, sensitivity, selectivity, stability and response slope when exposed to various carbon dioxide levels inside simulated grain bulk conditions