A New Calibration Apparatus of Port Quick Leak Detector for Spacecraft

The leak rate of spacecraft port must meet certain standards during the opening and closing processes. The port quick leak detector can be used to on-line measure leak rates of spacecraft port. In this work, a new calibration apparatus is designed and investigated. It can work at different temperatures with different gases in a wide leak rate range. This apparatus consists of the standard leak rate system, calibration system, temperature control system, gas supply and pumping system, which is designed on the basis of direct comparison calibration method and pressure-rising method with a constant volume, and the leak rates are provided by the standard leak rate system. The calibration range of the calibration apparatus is from 2 × 10 ^–6 to 2 × 10 ^–2 Pa m³/s. Its combined standard uncertainty is about 4.7%, and its calibration temperature is from ? 50 to 20 °C. Within the above leak rate and temperature ranges, the correction factor of the port quick leak detector is about 0.88–1.09.     

Manual / automated capacitance box using micro-controller technique

A capacitance box contains more than one decade capacitance. These decades have different capacitance ranges to get a much wider range of the capacitance steps obtained by the whole box. In general, a decade capacitance is constructed by ten capacitors to give ten manual capacitance steps. In this paper, a new design of a capacitance box is presented using two-decade capacitances. Each one of them is constructed by four capacitors only. This capacitance box is automatically controlled by especially designed programs using the Lab VIEW to provide a combination of 100 sequential capacitance steps from the common output of the two decades. These capacitance values can be used for the automatic calibrations of the capacitance measurement devices. Also, its capacitance steps can be obtained by manual way according to the user requirements, through an assembly language program using push-button switches. Control of each decade in this box depends on a micro-controller technique and four electronic relays as clearly investigated in this paper. Practical design, fabrication, and calibration for one decade of the capacitance box have been demonstrated in details through this research. The second decade in this box is the same as the first one, but it has different value of the capacitance per step.     

Preparation of High-Density Polyethylene/Exfoliated Graphite Composite via a New Method of in Situ Synthesis–Thermal Expansion and Determination of Antistatic Performance

A new method of in situ synthesis and thermal expansion was developed for preparing high-density polyethylene/exfoliated graphite composite. In the processes, an expandable composite was manufactured by high-density polyethylene and expandable graphite via the in situ synthesis. And then the final composite was prepared by the product obtained previously via the thermal expansion. The experimental results showed that the resistance values of the composite reached 2.58×10⁷, 2.50×10⁷, 2.46×10⁷, 2.41×10⁷, 2.34×10⁷, 2.31×10⁷, 2.27×10⁷, 2.22×10⁷ and 2.18×10⁷ Ω and the expansion volumes of the composite were of 14.0, 15.0, 16.0, 16.3, 17.0, 18.1, 19.0, 20.0 and 22.0 ml?g^?1 when the mass ratios were 10:1.0, 10:1.5, 10:2.0, 10:2.5, 10:3.0, 10:3.5, 10:4, 10:4.5 and 10:5.0 and the expansion temperature was at 160°C. This shows that all of the resistance values are at 10⁷ Ω, so the composite has the antistatic performance.     

Dual-Polarization-Sensitive Kinetic Inductance Detectors for Balloon-borne Sub-millimeter Polarimetry

We are developing arrays of kinetic inductance detectors for sub-millimeter polarimetry that will be deployed on the BLAST balloon-borne instrument. The array is feedhorn-coupled, and each pixel contains two lumped-element kinetic inductance detectors (LEKIDs) made of TiN. The absorbing, inductive sections of the LEKID-pair are orthogonal, which allows simultaneous measurement of both horizontal and vertical polarizations within one spatial pixel. In this paper, we show efficient absorption in TiN films when coupled to waveguide at room temperature and present dark measurements of single polarization devices with varying capacitor geometries. We show that it will be difficult to achieve background-limited performance in BLAST with stoichiometric TiN films with T \(_{c}=4.5\)  K, and that non-stoichiometric films with lower T \(_{c}\) will be required.     

The INRIM Role of Inter-laboratory Comparison Provider for Electrical Power and Energy at Industrial Frequency: A Two-Year Activity Report

The technical surveillance of secondary calibration laboratories accredited according to the ISO/IEC 17025 standard for electrical power and energy at industrial frequency is very important, as these measurements are the basis of the commercial relations between an electricity supplier and a user. An effective technical surveillance requires the execution of inter-laboratory comparisons (ILCs). With them, it is possible to verify the competence of the laboratories and the correctness of the dissemination process from the national standards of power and energy, usually maintained at national metrology institutes, to these laboratories. The paper deals with the ILCs that the National Institute of Metrological Research (INRIM) provided and carried out as reference measurements provider for Italian accredited laboratories for power and energy (active and reactive) at industrial frequency. The ILCs were carried out involving various instrument types and at different uncertainty levels. The 2σ relative uncertainties of the INRIM calibrations ranged from 1.0?×?10^?4 to 1.5?×?10^?3. The ILCs had satisfactory results confirming the correctness of both the dissemination from INRIM and the accreditation process by the Italian accreditation body for calibration laboratories.     

Annealing State Dependence of the Calibration of Type R and Type S Thermocouples

Type R (Pt–13 %Rh versus Pt) and type S (Pt–10 %Rh versus Pt) thermocouples are widely used as reference and working standards for temperature measurements both in calibration laboratories and in industry for temperatures up to 1600 °C. Many laboratories claim that the best achievable uncertainty is 0.1 °C up to 1000 °C and 0.3 °C up to 1550 °C, and international comparisons confirm that this is achievable practically. However, due to (i) preferential Rh oxidation of the Pt–Rh alloy thermoelement and (ii) defect quenching effects, these thermocouples suffer from reversible hysteresis in their calibration. As a result, calibration laboratories usually perform some heat treatment of the wire prior to calibration to attain a specific ‘annealing state’, at which the calibration is performed. Internationally, there are two commonly used annealing states for these thermocouples: the ‘450 °C annealed state’ and the ‘1100 °C quenched state’. High-level comparisons between laboratories in the calibration of type R or type S thermocouples will rigorously specify the annealing state in the protocol, so any systematic differences due to the choice of annealing state will be masked. This article compares the calibration of several thermocouples using the two common annealing states, finding that the difference can be as large as 0.2 °C at 961 °C, larger than the best calibration uncertainties reported. The article examines the advantages and disadvantages to the user of calibrations performed in each state, and the implications for the uncertainty analysis for calibration and use of type R and type S thermocouples.     

Anisotropy of acousto–optic figure of merit in lithium tetraborate crystals

We analyse anisotropy of acousto–optic figure of merit (AOFM) for Li₂B₄O₇ crystals in order to estimate the prospects of these crystals in acousto–optics. We find that the maximal AOFM, 3.44 × 10^?15 s³/kg, is peculiar for the isotropic acousto–optic interaction of the incident ordinary optical wave with the quasi-longitudinal acoustic wave. For the case of anisotropic diffraction in Li₂B₄O₇, the maximum 1.87 × 10^?15 s³/kg can be reached using the interaction of the extraordinary optical wave with the quasi-longitudinal acoustic wave. The case of collinear diffraction is characterized by small AOFMs, with the largest value 0.26 × 10^?15 s³/kg.     

Application of different types of carbon nanotubes as PIGE surface modifier in Pd(II) electrochemical determination

Nowadays, carbon nanotubes with differences in specific surface area, dopants, or functional groups are used in a number of applications, electrolysis not excluding. Various types of carbon nanotubes could improve bare graphite electrode properties by different way and so result in obtaining the different records for the same analyte. The automobile catalysts represent mobile sources of palladium. Levels of palladium in environment are continuously increasing and they need to be monitored. Electrochemistry is a useful and inexpensive component of the field of environment monitoring. For Pd(II) electrochemical determination, six types of carbon nanotubes were used as paraffin impregnated graphite electrode (PIGE) surface modifiers. Voltammetric determination brought interesting results of LOD, LOQ, standard and relative precisions of the method. These parameters as well as prediction intervals were calculated according to the technical procedure DIN 32 645 for the six electrodes and three pH values. Modification of PIGE with nitrogen doped carbon nanotubes (LOD = 1.91 × 10^?5 mol L^?1 or 3.14 × 10^?5 mol L^?1 for pH 3 and pH 4.5, respectively) seems very promising. In laboratory, functionalized carbon nanotubes, with specific surface area 200 m² g^?1, provided LOD = 1.49 × 10^?5 mol L^?1 (pH = 3) and 1.42 × 10^?5 mol L^?1 (pH = 4.5)     

Characterization of Capacitance Standards at High Frequency at National Physical Laboratory,India

Four-terminal-pair air dielectric capacitance standards with nominal values of 1000 and 100 pF have been characterized up-to 10 MHz at NPLI. The procedure employed involves the determination of all capacitive and inductive parameters of the simple electrical-equivalent-circuit-model of these capacitance standards. The effective capacitance of each standard has also been computed as a function of frequency from 1 kHz to 10 MHz. The capacitive parameters have been measured at 1 kHz while inductive parameters have been estimated up to 10 MHz using linear regression analysis by employing least-squares-approximation method. The paper highlights the computation procedure of impedance terms which further requires the determination of various capacitive and inductive terms involved in the calculation of effective capacitance. The method employed for the estimation of inductive parameters as a function of frequency is also discussed in detail. The present work will help in the establishment of metrological traceability of capacitance standards at high-frequency at NPLI which will be further used to establish calibration facility for LCR meters and RF impedance analyzers for capacitance parameter up-to 10 MHz.     

Electrical conductivity properties of boron containing Langmuir–Blodgett thin films

Electrical characterisations of Mesitylene-2-boronic acid (MBA), Phenylboronic acid (PBA) and 1-Naphthylboronic acid (NBA) are investigated using C-f and I–V measurements. All materials are used to fabricate Langmuir–Blodgett (LB) thin film by vertical dipping method. Metal/LB film/Metal sandwich structure is prepared to investigate electrical properties of boron containing LB films. For evaluation of electrical measurements, the theoretical thickness is determined using ChemDraw software and experimental thickness value is calculated from surface plasmon resonance (SPR) curves. Dielectric measurements are used to determine the dielectric constant (ε) and to compare refractive index value which is determined from SPR results. The values of ε are determined as 2.79, 2.70, 2.82 for MBA, PBA and NBA respectively. The refractive indexes of three materials are calculated to be around 1.6. I–V results are used to study the conduction mechanism of these LB films. The low voltage region shows an ohmic characteristic for each LB film and conductivity values are calculated as 0.55 × 10^?11 S m^?1, 0.42 × 10^?11 S m^?1 and 3.62 × 10^?11 S m^?1 for MBA, PBA and NBA respectively. In the high voltage region of I–V curves that show Schottky type conduction mechanisms with the barrier heights estimated for each LB film as 0.77, 0.79 and 0.76 eV respectively.     

Study on properties of forsterite/cordierite ceramic composites

The forsterite/cordierite ceramic composites are prepared by standard ceramic method, which properties and microstructures are characterized by X-ray diffraction and Scanning electron microscopy. It is found that the values of volume resistivities rapidly decline from 1 × 10¹³ to 10³ Ω cm as the testing temperatures increase from 20 to 600 °C and the resistivity transition temperatures of forsterite, cordierite and their composites are at about 300, 200 and 250 °C, respectively. The values of ε _r and tan δ are somewhat independent of the temperatures between 20 and 200 °C, but increase rapidly between 200 and 600 °C. The thermal expansion coefficient of ceramic composites decline with the cordierite content increasing and could change from about 2.5 × 10^?6–10.5 × 10^?6 °C^?1, in which the major phases are Mg₂SiO₄ and Mg₂Al₄Si₅O₁₈.     

Effects of borosilicate glass additions on microstructures and magnetic properties of low temperature co-fired NiCuZn ferrites

The low temperature co-fired NiCuZn ferrites with different borosilicate glass additions are prepared by a conventional solid-state reaction method. It is found that borosilicate glass additions can enhance densification of specimens based on liquid phase sintering and grain growth promotion. Small amount of borosilicate glass additions do not have a significant effect on forming into the main phase. But too much glass additions will damage the magnetic properties. As the borosilicate glass additions increase from 0 to 0.1 wt%, the permeability measured at 100 kHz decreases from 664 to 555, while the permeability values decrease rapidly from 310 to 169 with the glass additions rising from 0.3 to 0.9 wt%. The 0.1 wt% borosilicate glass can enhance the resistivity from 4.07 × 10¹⁰ Ω cm to 9.81 × 10¹⁰ Ω cm, while 0.9 wt% borosilicate glass addition leads to inhomogeneous grains and intragranular pores, resulting in deterioration of the resistivity to only 1.4 × 10¹⁰ Ω cm.     

Surface morphology and thermal figure of merit of a new compound thin film

The third nonlinear optical properties of a new compound 4,4′-bis(3-methoxy benzylidene amino) biphenyl doped poly-methyl methacrylate (PMMA) have been studied using Z-scan technique. Experiments are performed using a continuous waveguide (cw) diode laser at 532 nm wavelength and 0.68 kW/cm² laser intensity. The optical power limiting behavior of sample doped PMMA was also investigated. It also shows a very good optical limiting behavior with a limiting threshold of 4.7 mW. We attribute the nonlinear absorption and optical limiting property of the sample film to two photon absorption effect at 532 nm. The experimental evidences of observing diffraction pattern in compound 4,4′-bis(3-methoxybenzylideneamino) biphenyl doped PMMA has been present. The refractive index change, Δn, and nonlinear refractive index, n ₂ determined from the number of observed ring. We obtained good values of Δn = 105.154 × 10^?4and n ₂ = 154.154 × 10^?7 cm²/W. Variation of refractive index with temperature, dn/dT, and figure of merit, H, are found to be 8.858 × 10^?6 1/°C and 5.316 × 10^?6, respectively. This large nonlinearity is attributed to a thermal effect resulting from linear absorption. Theoretical diffraction pattern that agree well with experimental one are generated using a wave theory.     

Determination and Comparison of Temperature Coefficient of Standard Inductors by Measuring Change in Inductance and Resistances

This paper determines and compares the temperature coefficient of the standard inductors, manufactured by General Radio, using three different methods. The temperature coefficients have been determined by observing the change in inductance at 1 kHz and change in resistance at 1 kHz and 20 Hz. The standard inductor has been measured using precision LCR meter in a controlled and stable environment. The temperature coefficient is substantial when measured as a function of change in inductance in comparison to change in resistance as suggested by manufacturer. This information may be useful in computing the measurement uncertainty and analyzing the results of International comparisons and proficiency testing programs.     

Conditions for the generation of nano-sized Au agglomerates in Si

The conditions for the generation of nano-sized Au agglomerates in Si, which were recently discovered by the author, have been investigated. The agglomerates can be generated under very limited conditions. The agglomerates are generated with a continuous annealing method but are not generated with a typical ordinary annealing method. They are generated at an annealing temperature of 900 °C but not at 930 °C. Agglomerates are not generated in regions less than 6 μm from the surface. They are generated in a sample that is initially supersaturated with Au atoms at 7.5 × 10¹⁶ cm^?3 but are only generated at the boundary of the out-diffusion in a sample that initially contains Au atoms at 2.5 × 10¹⁶ cm^?3. Generation of the agglomerates becomes difficult as the time to cool to the annealing temperature increases in the continuous annealing process. The generated agglomerates dissolve and disappear as the surrounding Au concentration decreases to the thermal equilibrium value, that is, as the sample recovers from the supersaturation of the surrounding Au.     

Synthesis of zirconium silicide in Zr thin film on Si and study of its surface morphology

Zirconium silicide was synthesized on Si (100)/zirconium interface by means of swiftly moving 150 MeV Au ion beam. Thin films of zirconium (~60 nm) were deposited on Si (100) substrates in ultra high vacuum conditions using the electron-beam evaporation technique. The system was exposed to different ion fluencies ranging from 3 × 10¹³ to 1 × 10¹⁴ ions/cm² at room temperature. Synthesized zirconium silicide thin film reasonably affects the resistivity of the irradiated system and for highest fluence of 1 × 10¹⁴ ions/cm² resistivity value reduces from 84.3 to 36 μΩ cm. A low resistivity silicide phase, C-49 ZrSi₂ was confirmed by X-ray analysis. Schottky barrier height was calculated from I–V measurements and the values drops down to 0.58 eV after irradiation at 1 × 10¹⁴ ions/cm². The surface and interface morphologies of zirconium silicide were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM shows a considerable change in the surface structure and SEM shows the ZrSi₂ agglomeration and formation of Si-rich silicide islands.     

The Detector System for the Stratospheric Kinetic Inductance Polarimeter (Skip)

The stratospheric kinetic inductance polarimeter is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1,133 deg \(^2\) of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2,317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (Lekids). The Lekids will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, 5-day flights beginning with the 150 GHz observations.     

Effect of very low to high Sb-doping on the structural,electrical, photo-conductive and thermoelectric properties of fluorine-doped SnO<Subscript>2</Subscript> (FTO) thin films prepared by spray pyrolysis technique

Transparent conducting fluorine and Sb-doped [SnO₂: (F, Sb)] thin films have been deposited onto preheated glass substrates using the spray pyrolysis technique by the various dopant quantity of spray solution. The effect of antimony impurities on the structural, morphological, electrical, Thermo-electrical, optical and photoconductive properties of films has been investigated. The [F/Sn] atomic concentration ratio (x) in the spray solution is kept at value of 0.7 and the [Sb/Sn] atomic ratio (y) varied at values of 0, 0.0005, 0.001, 0.002, 0.01, 0.03, 0.05, 0.07 and 0.10. It is found that the films are polycrystalline in nature with a tetragonal crystal structure corresponding to SnO₂ phase having orientation along the (110) and (200) planes. SEM images indicated that nanostructure of the films has a particle type growth. The average grain size increases with increasing spraying quantity of Sb-dopant. The compositional analysis of SnO₂: (F, Sb) thin films were studied using EDAX. SEM and AFM study reveals the surface of SnO₂: (F, Sb) to be made of nanocrystalline particles. The Hall Effect measurements have shown n-type conductivity in all deposited films. The lowest sheet resistance and highest the carrier concentration about 7.7 Ω/□ and 6.6 × 10²², respectively, were obtained for the film deposited with y = [Sb/Sn] = 0.001 and x = [F/Sn] = 0.7. The maximum of the Seebeck coefficient equal to 12.8 μV K^?1 was obtained at 400 K for the film deposited with y = [Sb/Sn] = 0.10. The average transmittance of films varied over the range 10–80 % with change of Sb-concentration. The band gap values of samples were obtained in the range of 3.19–3.8 eV. From the photoconductive studies, the Sb-doped films exhibited sensitivity to incident light especially in y = 0.001. The electrical resistivity and carrier concentration vary in range 5.44 × 10^?4 to 1.02 × 10^?2Ω cm and 2.6 × 10²²–6.6 × 10²² cm^?3, respectively.     

Crystallographic, thermoelectric, and mechanical properties of polycrystalline type-I Ba8Al16Si30-based clathrates

Crystallographic, thermoelectric, and mechanical properties of polycrystalline Ba₈Al₁₆Si₃₀-based samples with type-I clathrate structure prepared by combining arc melting and spark plasma sintering methods were investigated. The major phase of the samples was a type-I clathrate with an actual Al/Si ratio of ~15/31, strongly suggesting that framework deficiency was absent or was present in very low concentration in the samples. The Hall carrier concentration n of the samples was approximately 1 × 10²¹ cm^?3, which is lower than the values reported so far for the Ba₈Al₁₆Si₃₀ system. Other important material parameters of the samples were as follows: the density-of-states effective mass m* = 2.3m ₀, Hall mobility μ = 7.4 cm² V^?1 s^?1, and the lattice thermal conductivity κ _L = 1.2 W m^?1 K^?1. The thermoelectric figure of merit ZT reached approximately 0.4 (900 K) for a sample with n = 9.7 × 10²⁰ cm^?3. Simulation using the experimentally determined values of material parameters showed that ZT reached values >0.5 if the carrier concentration is optimized at about 3 × 10²⁰ cm^?3. Young’s, shear, and bulk moduli were estimated to be approximately 98, 39, and 117 GPa, respectively, and Poisson’s ratio was found to be 0.25 from the longitudinal and transverse velocities of sound, v _L = 6038 m/s and v _T = 3503 m/s, respectively, for a sample with ZT = 0.4. The coefficient of thermal expansion (CTE) ranged from approximately 8 × 10^?6 K^?1 to 10 × 10^?6 K^?1 (330–690 K), which is smaller than the values reported for Ba₈Ga₁₆Ge₃₀ and Sr₈Ga₁₆Ge₃₀ clathrates.     

Effect of film thickness on properties of aluminum doped zinc oxide thin films deposition on polymer substrate

A series of aluminum doped zinc oxide thin films with different thickness (25–150 nm) were deposited on indium tin oxide coated polyethylene terephthalate substrates by radio frequency magnetron sputtering method at room temperature. The structural, optical and electrical properties of the films were investigated by X-ray Diffractometer, UV–Vis spectrometer and Hall Effect Measurement System. All the obtained films were polycrystalline with a hexagonal structure and a preferred orientation along [002] direction with the c-axis perpendicular to the substrate surface. The optical energy band gap (E_g) values of the films were found to be in the range from 3.36 to 3.26 eV, and their average optical transmissions were about 75 % in the visible region. The films had excellent electrical properties with the resistivities in the range from 2.78 × 10^?5 to 2.03 × 10^?4 Ω cm, carrier densities more than 3.35 × 10²¹ cm^?3 and Hall mobilities between 5.77 and 11.13 cm²/V s.