Thermo Vacuum Research Articles

Analysis of S-Parameters for RF Coaxial Cables at Different Environmental Conditions

RF coaxial cables are essential components in radio frequency and microwave systems. RF coaxial cables are necessary for the test and measurement systems. In spacecraft (TTC & Payload subsystem) testing, RF coaxial cables are used to uplink the signal from signal sources to spacecraft and receive the signal from spacecraft to measuring equipment. The performance of the RF coaxial cable can affect the test results of the spacecraft. The primary performance parameter for coaxial cable is the loss or attenuation. The losses are attributed to several factors and are present in all the RF Coaxial Cables. Environmental conditions affect coaxial cables, including temperature, pressure, moisture, dampness, etc. In this paper, an analysis of S-Parameters for RF coaxial cables at different environmental conditions is given. For this purpose, in the thermo vacuum chamber (TVAC), an experiment was conducted on N-type Polytetrafluoroethylene (PTFE) or Teflon coaxial cables during TVAC IST. A vector network analyzer and a computer with a LabVIEW-based application were used as a data acquisition system. All the processing of acquired data is done using the matrix laboratory (MATLAB) tool.

Substantiation into Parameters of Carbon Fuel Production Technology from Brown Coal

Technological solutions for brown coal processing, thermal influence on it at temperature change, thermo vacuum drying are analysed and qualitative and quantitative characteristics of semi – coking products are studied. The parameters of crushing and thermo vacuum drying of brown coal, heat treatment and cascade separation (electrostatic and magnetic) are substantiated. Studies on the manufacture of a pilot batch of carbon fuel with high quality characteristics are performed. Cascade treatment of heat-treated brown coal on electric and magnetic separators allowed to obtain a concentrate with ash content from 17.72 to 22.8%, volatile yield ≤ 35%, higher heat of combustion from 7256.1 to 7523.6 kcal/kg. It is determined that favourable modes of preliminary heat treatment of brown coal samples are in the temperature range of 200-400°С. The established characteristics of the obtained solid fuel correspond to the gas group of thermal coal. The obtained technological solutions for the processing of brown coal can be the basis for the manufacture of an industrial line, taking into account the thermo vacuum installation for further implementation in enterprises using carbon fuel.

Вивчення кінетики просочення базальтових, вуглецевих, оксидних волокон розплавами алюмінію та його сплавами

Wetting studies were performed by the sessile drop method using the capillary purification method of melt during the experiment in a vacuum of 2·10-3 Pa in the temperature range of 600–700 oC. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. Vanadium, copper and nickel metals were chosen for the coatings, which were sprayed on the materials by electron beam evaporation of metals in vacuum, and titanium, nickel powders for the coatings were used. The nature of the wetting angle dependence on the film thickness is a linear decrease in the angle with increasing film thickness. Studies have shown the possibility of using double films vanadium–copper, vanadium–nickel for the manufacture of composite materials from basalt fibers. The process of impregnation of basalt, carbon and oxide fibers with aluminum melts and its alloy with silicon in the temperature range 650–700 oC has been studied. The metal titanium, nickel powder coatings and films vanadium–copper, vanadium–nickel for the method of spontaneous free impregnation were used. Speciments of the composite material were obtained and the limit of destruction of these samples was determined. The bend strength of composites (basalt fiber 200 μm) is 270 MPa. Keywords: spontaneous free impregnation, composites, aluminium melts, basalt, carbon, oxide fibers, wetting, metal coatings and coverings.

Вивчення змочування та кінетики просочення оксидних волокон розплавами свинцю та його сплавів

The effect of metal coverings on wetting of oxide fibers by lead, bismuth, tin-lead-bismuth-cadmium alloy in vacuum 2·10-3 Pa in the temperature range 400–600 oC was studied by the sessile drop method using the capillary purification method of melt. Oxide fibers plaits that have been placed on a silicon oxide substrate as wetting substrates used. Titanium and nickel powders were used as metal coatings. There is no wetting. The contact angles are close to or greater than 90 degrees and only in the case of the lead-titanium melt system at 600 oC the value of the angle is 15, respectively. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. The metal titanium, nickel powder coatings for the method of spon¬taneous free impregnation was used. The study of the kinetics of impregnation of plaits of oxide fibers with melts of lead and tin-lead-bismuth-cadmium alloy was performed at 600–700 oC. The metal melt impregnates metal powders well. The rate of impregnation is quite high 1,1–1,8 mm/s. The obtained results allow the use of titanium pastes for the manufacture of composites from oxide materials with lead matrices. Composites were made. Oxide fiberglass made of CRT waste was selected as the reinforcing material. Lead was chosen as the matrix metal. Despite the fact that lead is a harmful material, but its use as a matrix phase for composites from the action of ionizing radiation is indispensable. Keywords: spontaneous free impregnation, composites, lead melts, oxide fibers, wetting, metal coverings.

Properties of modified wood according to treatment technology and thermo-vacuum process for birch (Betula pendula Roth) veneers

Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study. After modification of veneers in the range of temperatures from 160 °C to 218 °C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined. Treatment regimes with the greatest mass loss were at 217 °C for 3.0 h in TV (7.8%) and 160 °C for 0.8 h in the WTT (6.7%). As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r = 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57% and 40%, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12% to 33%. Among the investigated samples, the regime 217/3.0/TV showed the best resistance against brown rot fungus and acceptable other properties.

Quantum Entanglement via Thermo Excitation on the Thermo Vacuum State

We construct a new state via thermo excitation on the thermo vacuum state. It is interestingly found that partial tracing over thermo-freedom will lead to a negative-binomial state characteristic of l in the a-mode space and annihilating one a-mode photon results in increasing one $\tilde {a}$-mode photon, which exhibits quantum entanglement between system and environment. We employ the summation method within ordered product of operators to proceed our discussion.

Quantum effect of cooling down the environment temperature of mesoscopic LC circuit

ABSTRACTWe examine the quantum effect of cooling down the environment temperature of mesoscopic LC circuit, and find that the ground state of the circuit is no longer in the thermo vacuum state, but in a negative binomial state. We calculate energy of the circuit in this new state, which increases with the cooling of the environment.

Environmental stability of transparent and conducting ITO thin films coated on flexible FEP and Kapton® substrates for spacecraft applications

Acquiring good adhesion of ITO thin films on polymer substrate is a major concern, especially for space related applications. Delamination of ITO coating on these polymers can seriously damage the spacecraft. This paper presents the development of highly transparent and conducting ITO thin films on as-received and surface treated fluorinated ethylene propylene (FEP) and Kapton® substrates by reactive direct current magnetron sputtering. Stability of the ITO coating on FEP and Kapton® substrates was studied in simulated space environments. Environmental tests such as: relative humidity, thermal cycling and thermo vacuum were performed. Thermo-optical properties and sheet resistance of ITO coated FEP and Kapton® substrates were studied before and after environmental tests. Optimized ITO coating with thickness of ~ 15nm on FEP and Kapton® substrates showed sheet resistance in the range of 2–4kΩ/sq. with high average transmittance and high IR emittance. Adhesion of ITO coating on FEP substrate was improved by Ar plasma etching. X-ray photoelectron spectroscopy and field emission scanning electron microscopic studies of etched FEP substrate showed defluorination and high roughness of the etched surface which helped for better adhesion of ITO coating. We demonstrated that ITO coated plasma etched FEP substrate showed no change in the sheet resistance and thermo-optical properties. Moreover, ITO coated etched FEP substrate showed good environmental stability than ITO coated untreated FEP substrates.

Thermo Vacuum State for Describing the Density Operator of Photon-subtracted Squeezed Chaotic Light

For the density operator describing s−photon-subtracted squeezed chaotic light (PSSCL) we search for its thermo vacuum state (a pure state) in the real-fictitious space. We find that it reduces to a thermo vacuum state of squeezed chaotic light when s = 0, and to a thermo vacuum state of the optical negative binomial field when no squeezing. The new thermo vacuum state simplifies calculating photon number average, quantum fluctuation and Mandel’s Q parameter of PSSCL. Using the method of integration within ordered product (IWOP) of operators we also derive the normalization coefficient and explicitly analytical expressions of Wigner function for PSSCL.

Thermo vacuum state for Gaussian-enhanced chaotic light

In nature, there exists superposition of Gaussian light and chaotic light, so we introduce the density operator for describing the Gaussian-enhanced chaotic light (GECL). By virtue of the method of integration within ordered product (IWOP) of operators, we derive its normalization constant. Then, by virtue of the partial trace method, we derive its thermo vacuum state and this may greatly simplify the calculation of photon number average and quantum fluctuation in GECL. It is demonstrated that the second-order degree of coherence of GECL is larger than 2.

Investigating Mesoscopic Non-linear Series Circuit with the Coherent Thermo State Representation

For the first time we considered the quantum effects of mesoscopic non-linear series circuit with the coherent thermo state representation \(\left | \tau \right \rangle \). After introducing the representation \(\left |\tau \right \rangle \), we derived the expression of the density matrix ρ and find that \(\left | \rho \right \rangle _{T} \) presents Gauss type with the representation \(\left | \tau \right \rangle \). In addition, we derived the Wigner function and calculated the quantum fluctuation in the thermo vacuum state |0(β)〉. It is shown that the circuit has the zero current fluctuation because the diode has the reverse saturation current, and the temperature affects the Wigner function of the circuit in thermo vacuum state deeply.

Evolution of l-photon excited thermo vacuum state in a single-mode damping channel

In this paper, we investigate how a kind of non-Gaussian states (l-photon excited thermo vacuum state [Formula: see text]) evolves in a single-mode damping channel. We find that it evolves into a Laguerre-polynomial-weighted real–fictitious squeezed thermo vacuum state, which exhibits strong decoherence and its original nonclassicality fades. In particular, when l = 0, in this damping process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic. In overcoming the difficulty of calculation, we employ the summation method within ordered product of operators, a new generating function formula about two-variable Hermite polynomials is derived.

Expectation Value Theorem for Thermo Vacuum States of Optical Chaotic Field and Negative-Binomial Field

For the density operator (mixed state) describing chaotic light and negative-binomial field there exist the corresponding thermal vacuum state (pure state) in the real-fictitious space. Using the method of integration within ordered product of operators we find the expectation value theorem in these two thermo vacuum states respectively. The thermal average theorem of translation operator is also deduced. Application of the new thermo vacuum state in calculating photon number disturibution and fluctuation and thermal average is presented.

Design and realization of pure LN2supply system for cooling of black body targets to qualify meteorology payloads

Radiometric calibration of meteorological payloads like IMAGER and SOUNDER of INSAT-3D is mandatory to evaluate the instrument for its onboard performance at different temperatures. For such calibration, black body targets (BBTs) are required to be maintained at different constant temperatures within the calibration temperature range. During operation of BBTs, supply of pure LN2 at a constant pressure controlled within 20–25 PSI is essential to control temperature stability and reduce cooling time for each BBTs. simultaneously other subsystems of thermo vacuum chamber needed supply of pure LN2 in the range of 60 – 80 PSI. To handle this situation, various options were studied and based on the merits of each option, it was concluded to incorporate a phase separator system with its own pressure control system which will serve these competing requirements and provide required immunity to the BBT system from other system fluctuations.

Autocatalytic silver-plating of aluminium radio frequency waveguides with autocatalytic nickel as the undercoat for space applications

Autocatalytic plating, a technique used for evenly coating contoured items with deep cavities, such as microwave components, irrespective of shape and size of the item to be plated, was used in this work to coat a radio frequency waveguide. In this work, a process sequence was developed for autocatalytic silver plating on aluminum base material with autocatalytic nickel as the undercoat. The thickness of the deposited silver depends on variables like temperature, concentration of silver ions in the electrolyte, and the pH of the solution. The influence of these variables was studied under different process conditions. Silver-coated rectangular plates were subjected to various tests, including a bend test, a heat resistance test, a thermal cycling test, a thermo vacuum test, a solderability test, and a humidity resistance test. Autocatalytic silver-coated RF waveguide WR28 was tested for insertion loss and return loss. Autocatalytic silver-plated rectangular plates and waveguides were found to withstand a simulated space environment.

Structure and Gas Sensitivity of the ZnO Sensor of Ethanol

In this paper we describe our studies of the influence of substrate nature and type of doping on the structure and sensor properties of thin films of ZnO, obtained on the surface of glass, quartz, pyroceramics, leuco-sapphire and oxidized silicon by thermo vacuum deposition. With X-ray investigation it is shown that the obtained films consist of nanocrystalline zinc oxide, regardless to the nature of the surface, and the best structural perfection characterized ZnO film on the surface of the quartz and glass. The sensitive properties of zinc oxide films to ethanol vapors can be greatly improved by introducing of doping impurities (Al or In), the highest sensitivity to ethanol was detected for the films of ZnO:Al on the quartz substrate. The proposed sensor can be used to monitor gas environments in the food industry and in the evaluation of alcohol in humans breathing.

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of "Open loop, auto reversing liquid nitrogen based thermal system". System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

FLUCTUATION OF MESOSCOPIC RLC CIRCUIT AT PHOTON-SUBTRACTED AND PHOTON-ADDED THERMO VACUUM STATES WITH FINITE TEMPERATURE

By using the Wigner function to evaluate expectation values of any symmetrically order of operator in a classical fashion, we study the quantum fluctuation and the uncertainty relation of mesoscopic RLC circuit at photon-subtracted and photon-added thermo vacuum states. It is found that the fluctuations and the uncertainty relation of both charge and current are linearly related to the photon-subtracted and photon-added number.

Evolution of a Thermo Vacuum State in a Single-Mode Amplitude Dissipative Channel

We investigate how an initial thermo vacuum state, in the context of thermo field dynamics, evolves in a single-mode amplitude dissipative channel, and find that in this process the thermo squeezing effect decreases while the fictitious-mode vacuum becomes chaotic.

Generalized Thermo Vacuum State Derived by the Partial Trace Method

By virtue of the technique of integration within an ordered product of operators, we present a new approach for deriving the generalized thermo vacuum state which is simpler in form than that obtained from the Takahashi—Umezawa method. using this new approach, the thermo field dynamics can be developed. Applications of the new state are discussed.