Introduction

Corona gas discharge produces a typical glow on devices with a 5 to 30 kV voltage and frequencies from 10 to 150 kHz ¹. In 1949, ² received a patent for a “Method for obtaining photographic pictures of different types of objects”.

The method of selective electric discharge allows for a dielectric medium to record information on another that is in contact with it. It is based on electric discharge at normal atmospheric pressure in a three-layer condenser: dielectric-air gap-dielectric ^3,4. A constant and controllable by-force electric field is created in it. In certain places where the electric field surprises the breakdown value of the field in the air gap, a perforation in the last one occurs. Pashen’s law ⁵ describes this phenomenon as:

(1)

V_B depends on p and d.

Due to perforation, electric discharge is selectively remitted on the recording electric medium.

In 1965, ⁶ has published an electrophotography book with corresponding technology for directly capturing corona discharges from biological objects, especially around larger contact surfaces. Electrophotography is by far the most significant of all the reprographics technologies for photocopying and laser/LED printing.

In 1975, ⁷ have described the gas discharge effect with copying on the photographic photo film as electrophotography.

Since 1960, ^8,9 have developed electrophotographic methods for images registration.

In 1968, ⁴ has developed a method for gas discharge photography. ^10-18 have also made researches in this area. During the process, in the ionization zone, sliding discharge develops on a dielectric surface powered by a non-uniform electric field near an electrode with a small curvature radius. The small gap thickness between the experimental object and the electrode ranges from 10 to 100 µm.

Experimentally, the gas discharge effect gives information on the electric field distribution in the air gap between the object and the registering medium during the discharge ^{1), (19-21}. Ions of N, O, CO₂ and free electrons form the discharge itself. The free electrons are separated from N₂, O₂ and CO₂ molecules, which generate gas discharge between the studied object and the electrode ^22-24.

Research has focused on analyzing an insight conclusion about digital analysis on the corona gas discharge spectrum, by introducing a pre-processing procedure to extract the texture effects as the radiation energy signature based on its most significant glow (digitally imaged isolines), which is used for medical biometric and disease interpretations ²⁵.

During corona gas discharge in the atmosphere, there is a process of CO₃ ^- formation ²⁶. When CaCO₃, H₂O and CO₂ are combined, the following reaction is observed ²⁷.

(2)

²⁸ have developed a gas discharge photography method that that described the reaction as:

(3)

Falk has shown that HOH bending is fundamental for solids and liquids ²⁹.

CaCO₃ has the most extensive local extremums at 873 ³⁰ and 1457 cm^{-1 (31}.

Studies employing NES and DNES ^33-35 methods with 873 cm^-1 were made for cave water ³², the environment process ³⁶ and plants with Ca^{2+ (36,37}.

The present investigation aimed to prove that, in coronal gas discharge conditions, there is an activation of the separated photons processes for CaCO₃ ions and H₂O reactions.

Materials and methods

Device for color coronal spectral analysis

Gas discharge emission for color coronal spectral analysis ^{1), (21), (23), (37), (38} was investigated in a dark room. It was registered with a photosensitive paper or color film placed on transparent Hostaphan electrode with an 87 mm diameter. It was filled with a conductive liquid composed of a 1% NaCl solution in deionized H₂O. Herein, the 1% solution was made from CaCO₃. Investigated objects (H₂O drops and human thumbs) were placed on the corresponding photosensitive material. Pulses with 12 kV voltage and a carrier frequency of 15 kHz were applied between the objects and the electrode Cu coating.

The functional scheme of gas corona discharge device is shown in Fig. 1.

Figure 1: Functional scheme of gas corona discharge device. 

Corona gas discharge was generated in the gap between the investigated objects and the transparent electrode, producing a characteristic glow around the contact area. Its electromagnetic emission, which ranged from 380 to 495 nm and 570 to 750±5 nm, illuminated the corresponding photosensitive material, according to the objects specific properties (Fig. 2) ³⁹.

Figure 2: Transparent electrode with 87 mm diameter made of Hostaphan and filled with conductive liquid (1% CaCO₃ in a distilled H₂O solution). 

Color images produced by visible, UV and IR radiation were processed and analyzed with a dedicated software package. Measured spectral characteristics were calculated in eV.

FTIR

IR-spectra of CaCO₃ were registered on a Brucker Vertex (“Brucker”, Germany) FTIR (spectral range: average IR- 370 ÷ 7800 cm^-1; visible- 2500 ÷ 8000 cm^-1; permission- 0.5 cm^-1; accuracy of ṽ - 0.1 cm^-1 on 2000 cm^-1) and Thermo Nicolet Avatar 360 FTIR spectrometers.

NES and DNES methods

θ was measured with a specially designed instrument, which has been described in detail by ^40-43. H₂O drops evaporation was performed in a sealed chamber with a stable temperature of 22 ºC and humidity from 65 to 70% ^{(40, 43)} (Fig. 3). The drops were placed on a 350 µm thick BoPET sheet.

Figure 3: Operating principle of the method for measuring the liquid drops θ on a hard surface: 1- drop, 2- thin Maylar sheet, 3- glass plate and 4- refraction ring width. 

θ is a function of a and d₁.

The device had the following technical features: monochromatic filter with λ of 580±7 nm; H2O evaporation angle ranging from 72.3 to 0 deg; measured range of hydrogen bonds energy among H2O molecules was λ = 8.9 ÷13.8 µm or E = -0.08 ÷ -0.1387 eV.

Luck has considered that, in H₂O, hydrogen bonds exist between H atom of one H₂O molecule and O of another ⁴⁴. Most of them are bound by the connection energy (-E) and the remaining are free (E = 0). It is accepted that E has a negative value. This is known as Luck’s two-state model ^45-48. The number of hydrogen bonds between H atom of one H₂O molecule and O of another in a volume of H₂O is twice as high as the number of molecules it contains.

Part of the hydrogen bonds is restructured in the proximity of the drop surface spherical part and which produces dependence between δ and hydrogen bond energy ^49-51.

(4)

where k is Boltzmann constant, E is hydrogen bond energy, α is the ratio of the phase space two sub-volumes related to hydrogen bonds (α = 28±8) structuring and restructuring, and I (5.03.10¹⁸ m^-2) is H₂O molecules density in the hydrophobic surface layer. E and α values were determined by comparison with the experiment. Expression (4) explains fraction C as δ = Cγ ⁵⁰. According to ^43,50, non-hydrogen bond interaction contribution amounts to 20% of γ and C real value (= 4/5). Considering Helmholtz free surface energy:

(5)

where Σ is the drop surface spherical part ⁴³.

At the instant of mechanical equilibrium, F should be minimal, i.e., dF = 0 = d(γΣ) ⁴³.

(6)

H₂O drops forced evaporation process occurs at a constant temperature of 20 ºC in a hermetic camera ⁴⁰.

Expressions for Σ₀ and Σ are as follows ⁴³:

(7)

(8)

(9)

During the process, θ changes in discrete steps and characterizes hydrogen bonds average E as follows:

(10)

(11)

where b is a temperature-dependent parameter ^52,53. The employed methods were NES and DNES ^53-55. They are used for research on natural waters ^37,53,55, plants ³⁵ and blood serum ⁵⁶. Molecular dynamics simulation was applied to investigate H₂O droplets wetting behavior on the sandstone surface under different salinities. The system equilibrium configuration was used for studying the interaction of its components. The number of hydrogen bonds was calculated ^57,58. E of hydrogen bonds among H₂O molecules in H₂O samples is measured in eV. A non-equilibrium evaporation process of H₂O droplets characterizes f(E) of H₂O. NES is measured in еV^-1. DNES is defined as the difference ^53-55:

(12)

DNES is measured in еV^-1, where f (*) denotes evaluated E ^50-54.

Results

Parameters of 1% CaCO ₃ in a distilled H ₂ O solution obtained by color coronal spectral analysis

Electric discharge per unit area of the recording medium can be expressed as follows ²⁰:

(13)

where δ = d₁/ε₁ + d₃/ε₃; T is electric pulse duration; U_p is VB of the air gap between experimental object and recording medium; d₁, d₂ and d₃ are the thickness of the object, air gap, and photosensitive material, respectively; ε₀ (1.00057 F/m^-1), ε₁ and ε₃ are dielectric permittivity of air, experimental object and photosensitive material, respectively.

VB of the air gap is:

(14)

Consequently, a quadratic equation describing the width of the air gap is obtained:

(15)

It has the following solutions:

(16)

Coronal gas discharge method has applications for researching H₂O drops electrical parameters in gas discharge conditions ⁵.

The dielectric constant as a parameter of coronal gas discharge was described by ^3,10. It is a reliable dielectric permittivity in a homogenous medium.

The object conductivity is not practically reflected in the formation of the electric image. The image gives information on the dielectric and geometrical object characteristics, dielectric permittivity distribution and surface unevenness ^5,9.

Dielectric permittivity is determined by the ability of a material to polarize due to an applied electric field, thereby partially neutralizing it in the material. Polarization refers to the displacement or orientation of associated electrical charges under the action of a field.

Investigation with the method of color coronal spectral analysis ^{1,21), (22), (37,38} was performed on the electric glow of the control sample (distilled H₂O) and 1% CaCO₃ in a distilled H₂O solution (Fig. 4).

The electrode from Fig. 2 was positively charged. The negative electrode was approached until a corona breakdown voltage occurred.

Figure 4: Color coronal images of the control sample (distilled H₂O) and of the specimen with 1% CaCO₃ in a distilled H₂O solution. 

Fig. 4 illustrates that the photon emission for the control sample was E = 2.05 eV or λ = 605 nm, and the average outcome was in the Em orange range. The result for the 1% CaCO₃ sample was E = 2.98 eV or λ = 416 nm, i.e., the average outcome was in the Em violet range. The difference was E = 0.92 eV. H₂O drop radius was 0.41 cm or S = πr². S = 3.14 x 0.41² = 0.528 cm².

For the control sample, the result was 2.11 eV/0.528 cm² = 4.00 eV/cm^-2. The result of the 1% CaCO₃ sample was 2.98 eV/0.528 cm² = 5.64 eV/cm^-2.

The outcome of a discharge at the liquid drops point of contact with the photo film is valuable. For distilled H₂O, V_B had 31% discharge with photons in the red Em, where E = 1.68 eV or λ = 738 nm. With 1% CaCO₃, there was 73% discharge with photons in the violet Em, where E = 3.02 eV or λ = 410.5 nm.

The method for brightness estimation from coronal discharge emission research was developed ^{19), (59}.

The formula calculates P_eff of the device for color corona discharge:

(17)

where U = 12 kV. Corona discharge for H₂O drop was R = 10⁹ Ω. P_eff = U²/R = 12²10⁶/10⁹= 0.144 W.

Results with pH and electric conductivity

Table 1 shows the change of parameters for 1% (w/v) CaCO₃ after 30 sec corona gas discharge, where U = 12 kV and ν =15 kHz.

There was an increase in the studied electric conductivity and pH values. The number of OH- hydroxyl groups also increased with higher pH values.

There was a statistically significant difference between the 1% CaCO₃ solution in distilled H₂O before and after the coronal effect, according to the Student’s t-test at p < 0.01 level.

Results of reactions with CaCO ₃

The research on CaCO₃ was performed with FTIR, which showed that the peaks at ṽ = 713, 873, 1457, 1627, 1793, 2512 and 3447 cm^{-1 (60), (61} (Fig. 5).

DNES of H₂O was studied from Temnata dupka (Dark hole) cave with Ca²⁺ and HCO₃ ^- contents of 66 and 223 mg/L^-1, respectively. A peak was observed at E = -0.1087 eV, λ = 11.41 μm and ṽ = 877 cm^-1. FTIR analysis of CaCO₃ had the following results: E = -0.1082 eV; λ = 11.46 μm; and ṽ = 873 cm^-1. H₂O vapor spectral range ranged from 0 to 877 cm^{-1 (62}. Adsorption peaks for CaCO₃ were at 713 and 875 cm^-1. The results indicate that an analysis of peaks at 713 and within the interval of 873 ÷ 879 cm^-1 can be used to evaluate NES processes with CaCO₃ in H₂O and air. Since exposure to H₂O with different physicochemical parameters, air moisture, and thermal effects can be assessed, the quality of CaCO₃ solutions and protection against CO₂ emissions is stronger.

Figure 5: FTIR results for CaCO₃. 

The present study illustrates an increase in f(E) peak at 877 cm^-1, from 32.6 to 39.9 eV^-1, during the process of coronal discharge on 1% CaCO₃ in a distilled H₂O solution (Table 2).

There was a statistically significant difference between 1% CaCO₃ in the distilled H₂O solution after and before coronal discharge effect, according to Student’s t-test at p < 0.05 level, with r of 0.964.

Conclusions

Color corona spectral analysis method has been applied for studying CaCO₃.

The following conclusions were drawn: a difference in the discharge parameters of H₂O drops was observed for 1% CaCO₃ in distilled H₂O before and after coronal discharge effect; there was an increase in electric conductivity and pH studied parameters; the number of OH- hydroxyl groups also increased with higher pH values.

During the coronal discharge process with 1% CaCO₃ in a distilled H₂O solution, this study illustrated the increase in the peak of energies distribution function for hydrogen bonds among H₂O molecules f(E) at 877 cm^-1, from 32.6 to 44.9 eV^-1. These findings have applications for chemical processes with color corona discharge on CaCO₃.

There were corona gas discharge effects from the primordial atmosphere to H₂O. In 1952, Miller-Urey experiments were performed with gas discharge effects in laboratory conditions. Twenty organic molecules have been structured from the following inorganic compounds: H₂O, CH₄, NH₃, H₂ and electric discharge ⁶³. Different scientists have repeated the Miller-Urey experiment.

In 1968, ⁶⁴ have synthesized porphyrin using a device with U = 12 kV. In 2014, ¹ investigated corona discharge and protocells synthesis with the same value ⁶⁴. In 2021, ³⁹ published chemical reactions of polar molecules in H₂O with gas discharge conditions. In 2021, ⁶⁵ have studied Miller-Urey experiment processes in a silica medium with U = 30 kV.

Authors’ contributions

Ignat Ignatov: conceived the research paper original idea; collected data; performed experimental work; inserted data or analysis tools; wrote the paper. Christos Drossinakis: collected data; performed experimental work; and analyzed data obtained by xperiments. Alexander I. Ignatov: collected data; performed experimental work; and wrote the references.