Deconvolution Procedure Research Articles

Fast co-pyrolysis of corncob with plastics: Evaluation of thermal behavior using deconvolution procedure, kinetic analysis and product characterization

In this study, the co-pyrolysis of corncob (CC) with polyethylene terephthalate (PET) and polyvinyl chloride (PVC) was first carried out at different blending ratios in a concentrating photothermal TGA (CP-TGA) to gain insights into their thermal behavior, pyrolysis characteristics and kinetic analysis under high heating rate conditions (≥500°C/min). The change in comprehensive pyrolysis index (CPI) for CC/PET and CC/PVC blends was 514 % and 125 %, respectively, when their blending ratio was increased from 25 wt% to 75 wt%. The decomposition rate (Rp %/min) for CC/PET and CC/PVC blends with an increased heating rate showed a favorable co-pyrolysis process. Rapid heating leads to complexity and simultaneous overlapping of the co-pyrolysis components; therefore, the devolatilization phase (active pyrolysis zone) was divided into pseudo-reactions using the Fraser-Suzuki deconvolution function. The deconvolution results of the blend samples fitted well with experimental results (R2 ≥ 0.997). The three pseudo components of CC in the CC25PET75% blend relatively reduced the needed activation energy (E) for PET degradation to about 130 %. With the blending ratio increase, the synergistic activity of pseudo hemicellulose presented trends of an increasing E in CC/PET blends, whereas CC/PVC blends showed decreasing trends. The relative ΔEa deviation revealed that most blend samples would promote an active synergistic reaction. The resultant co-pyrolysis oil from photothermal fixed bed pyrolyzer contained promising bio-renewable platform chemicals such as levoglucosenone, furfural, D-allose, etc. The synergistic interactions between pseudo-lignin and PET contributed to a significant reduction in activation energy and higher selectivity of acetic acid due to the degradation of the ester bonds in PET and the carboxyl groups in lignin. The results of this work could serve as a guide for selecting appropriate reaction parameters for optimal co-pyrolysis synergism.

Single-shot intensity diffraction tomography via polarization-multiplexed LED illumination.

We present a single-shot intensity diffraction tomography method via polarization-multiplexed LED illumination. Three LED elements covered with 0°, 45°, and 135° linear polarizers, respectively, are lit up simultaneously to illuminate the sample with illumination angles matching the numerical aperture of the objective. The scattering field of the sample is recorded on a single intensity image with a polarization sensor, and three intensity images corresponding to the three LED elements are decoupled from the intensity image by using a pre-calibrated intensity transform matrix. After a slice-wise deconvolution procedure, the 3D complex refractive index distribution of the sample can be recovered. To demonstrate the performance of our method, we perform experiments on a USAF absorption resolution target, rat hippocampal cell lines, and spongy spicule. These imaging results show that our method can achieve 3D tomography for various biomedical samples with a near incoherent diffraction-limited lateral resolution of 690 nm and an axial resolution of 4.68 μm.

Exploring temperature effects on raw polysaccharide in semi-diluted solution using complex conductivity: Correlation analysis of activation energies

The evolution of the complex conductivity of raw polysaccharides extracted from Cystoseira myriophyloides algae exhibited significant temperature dependence in an aqueous solution. An analysis of the complex conductivity versus frequency was conducted using an appropriate electrical circuit based on our theoretical approach. This facilitated the generation of analytical functions representing the relaxation processes occurring at different temperatures. Subsequently, extrapolation and deconvolution procedures were employed to further investigate and identify all relaxation processes and their origins. These approaches revealed the presence of three relaxation processes. The first relaxation, observed at low frequency, is attributed to interfacial polarization between the electrode and the solution. The second and third relaxations, observed at medium and high frequencies, are attributed to bulk relaxation processes. Then, subtracting the low-frequency process clarified the bulk relaxation processes. Both relaxations are described by the Cole-Cole relaxation, which effectively models the well-known Maxwell-Wagner-Sillars (MWS) phenomenon typically observed in polyelectrolyte solutions. This relaxation is typically caused by interfacial polarization between molecular chains and counterions in the sample. Both relaxations were found to be thermally activated. The temperature dependence of useful parameters extracted from each relaxation, such as relaxation time (τσ) and conductivity (σdc) and (σ∞), followed Arrhenius law behavior. Furthermore, activation energy values for each relaxation process were determined, establishing a linear correlation between activation energy values related to relaxation time (τσ) and both conductivities (σdc) and (σ∞). These results confirm the origin of bulk relaxations and demonstrate a strong link between relaxation and conduction mechanisms.

Microscopic Interaction of Oleated Cellulose and Silica in Dual-Filled Elastomers

The quantification of interactions between fillers and filler with elastomers in nanocomposites relies on the combination of different microscopy techniques. Small Angle X-ray scattering is a key method for the identification of the filler network morphology at the nanoscale. Hybrid nanocomposites containing fillers with diverse morphology and reinforcing ability represent considerable complexity thereby justifying ongoing research in this area, as a consequence of the multiple interactions between fillers and also the filler with the elastomer. Therefore, a microscopic structural investigation of a dual-filled elastomer for tire applications is presented. Chemically modified micro-fibrillated cellulose in combination with traditional silica filler dispersed by melt processing in a styrene-butadiene (SBR) random copolymer were investigated. Small-Angle-X-ray Scattering and Scanning-transmission-electron-microscopy (STEM) revealed non-mixing of the two fillers on the silica scale and the predominant formation of individual filler clusters. Through a novel data deconvolution procedure, partial structure functions corresponding to the contribution of each filler to the scattering function were extracted. This approach offers a suitable methodology to identify the compatibility between morphologically different fillers and their mutual effect on the dispersion.

Impact of TiO2/B2O3 ratio on the structure and optical properties of Na2O–CoCl2–TiO2–B2O3 glass

In this study, borate glass doped with constant cobalt chloride (CoCl2) content and different ratios of TiO2/B2O3 were prepared using the melt-quenching technique. The influence of the TiO2/B2O3 ratio on structure, optical, magnetic, electronic transitions, and linear and nonlinear optical features was studied. Structurally, XRD confirmed the amorphous structure, while EDX confirmed the incorporation of titanium cation. Meanwhile, the density increases, and the molar volume reduces with further ratios of TiO2/B2O3 to the glass matrix. Also, FTIR spectra confirmed the decreased presence of non-bridging oxygens (NBO), and different structural units such as BO3 and BO4. Optical studies showed the formation of absorption bands at about 301–327 nm, 375 nm, and 434 nm with TiO2/B2O3 ratios. Deconvolution procedures are necessary to detach the three electronic transitions and the glass absorption edge. The three electronic transitions can be explained in terms of titanium cations (Ti) oxidation states where Ti3+ cations display absorption bands in the wavelength range 440–480 nm. In contrast, Ti4+ cations display no absorption bands in the visible range but only show ultraviolet absorption bands. According to the electronic transition associated with Co cations are; the band at ∼497–500 nm is associated with 4T1g (F) → 2T1g (H) octahedral electronic transitions of Co2+ cations, while the band positioned at 577–578 nm is associated with 4A2 (4F)→4T1(4P) tetrahedral electronic transitions of Co2+ cations. The band is positioned at 648–650 nm and is associated with 5T2g→ 5Eg octahedral electronic transitions of Co3+ cations. On the other hand, with increasing TiO2/B2O3 ratio, optical band gaps decrease from 3.51 eV to 3.15 eV, and the samples color transformed from light blue to dark blue. Furthermore, the addition of TiO2/B2O3 ratio increases the linear and nonlinear refractive indices. ESR data indicate that Co2+ ions exist in both octahedral sites, with g ⁓ 4.10, and tetrahedral sites, with g ⁓ 2.40. Finally, we concluded the significant influence of the TiO2/B2O3 ratio on the structure, optical and magnetic properties, and linear and nonlinear optical parameters of cobalt borate glass. These results recommend the present glass samples for future applications in various photonic devices within the visible range.

Pyrolysis kinetics and thermodynamic behavior of pseudo components of raw and torrefied maple wood

ABSTRACT In this work, pyrolysis kinetics and thermodynamic behavior of pseudo components (PCs) of raw and torrefied maple wood (MW) were studied. The MW torrefaction experiments were conducted at 240°C and the pyrolysis process was performed under three distinct heating rates. Through the deconvolution procedure, three PCs, i.e. pseudo-hemicellulose (PC-HC), pseudo-cellulose (PC-CL), and pseudo-lignin (PC-LG), were identified. The activation energy (E α ) of PCs were evaluated using the Starink method, and the pyrolysis reaction mechanisms were analyzed using the Criado’s master plot method. Furthermore, three thermodynamic parameters were also calculated and discussed. Results showed that after torrefaction, the PC-HC content dropped from 47.30% to 7.90%, while the PC-CL and PC-LG contents increased from 33.67% to 55.72% and from 19.03% to 36.38%, respectively. The average E α of raw MW PC-HC, PC-CL and PC-LG were 114.56, 117.12 and 116.02 kJ/mol, respectively, whereas they were 92.86, 103.82 and 159.26 kJ/mol for torrefied PCs, respectively. The master plot results suggested that the pyrolysis of MW PCs involved different order-based models. In addition, the thermodynamic analysis revealed that the torrefied PC-HC required slightly less heat energy during pyrolysis. All these observations can be conducive to better understand the pyrolysis mechanisms of raw and torrefied MW PCs.

Insight into the pyrolysis of bamboo flour, polylactic acid and their composite: Pyrolysis behavior, kinetic triplets, and thermodynamic parameters based on Fraser-Suzuki deconvolution procedure

Kinetic triplets and thermodynamics are important in the design of pyrolysis processing. In this study, the non-isothermal kinetics and thermodynamics of pseudo components of bamboo flour (BF), Polylactic acid (PLA), and the resulting BF/PLA composite were investigated using Fraser-Suzuki deconvolution. Fourier-transform infrared spectra (FTIR) was used to characterize the gaseous products. Results showed the Fraser-Suzuki deconvolution curves fitted well to the experimental data. For pseudo hemicellulose and pseudo components in PLA, common kinetic models were applied. The pyrolysis of pseudo cellulose met the random scission model and pseudo lignin need to be described with empirical model. The Kinetic models were verified and shown to be in good agreement with the experimental results FTIR results indicated that more radical reactions occur in PLA during co-pyrolysis with BF.Thermodynamic results indicated the pyrolysis of pseudo components were non-spontaneous reactions except lignin. These results will contribute to reactor design and scale-up in future.

Investigating the influence of absorber layer thickness on the performance of perovskite solar cells: A combined simulation and impedance spectroscopy study

Absorber thickness is one among keys parameters that can have significant effects on the performance of the solar cell. An appropriate absorber thickness should be chosen to optimize the performance of the cell.The main objective of this work is to offer a perovskite solar cell with high efficiency using a suitable thickness of the active layer. Therefore, this study focuses on the optimization of the solar cell thickness, which can also be achieved by using simulation with SCAPS-1D, to predict the performance of the cell at different thicknesses. In this case, the four main parameters; the short circuit current density, the open-circuit voltage, fill factor and power of conversion efficiency, were extracted and analyzed from I–V characteristics at different thicknesses. In addition, the complex impedance data were also generated by using simulation with SCAPS-1D. To the best of our knowledge, this approach was not used before for many works carried out by SCAPS-1D simulation; where these studies were limited to I-V characteristics. This novel approach to investigating the electrical response of this solar cell concerning thickness involves the integration of complex impedance and modulus functions. This integration enables us to discern the respective contributions of ionic diffusion and recombination processes, through our deconvolution procedure, the results obtained indicate the absorber layer thickness increases, the diffusion and recombination processes are affected differently, subsequently influencing the overall performance of the solar cell. Both methodologies employed in this study consistently identified the maximum efficiency at an optimal thickness of 700 nm.

Time-domain deconvolution procedure for elastoplastic materials: Application to the Treasure Island site during the 1989 Loma Prieta earthquake

When dynamic soil-structure interaction (DSSI) analyses are performed, e.g. using the finite element (FE) method, the input signal is required at the base of the model. Nevertheless, acceleration records are usually available at the surface and, therefore, the desired motion must be deconvolved to the base. The latter is usually performed through the solution of one-dimensional propagation of shear waves in an elastic medium, in the frequency domain. Herein, nonlinear behavior is generally incorporated through the equivalent-linear method, by iteratively reducing the stiffness and increasing the critical damping ratio as a function of the maximum strains attained in each iteration. However, if complex material models are adopted to characterize the soil, the input motion derived with the equivalent linear method will not be compatible due to the simplified approach used to represent the nonlinear behavior. In this article, the use of a procedure to perform a time-domain deconvolution in non-linear elastoplastic materials is demonstrated. The goal is to generate input accelerograms at the base of a FE model to perform DSSI analyses. The procedure is based on the iterative modification of the motion at the base according to the relative differences between the propagated and target surface spectra. To illustrate the use of the methodology, it was applied to a FE model of the Treasure Island site (San Francisco, US), to derive the required motion at the base from a record of the Loma Prieta earthquake.•This article provides a useful guideline to optimize the use of the deconvolution procedure to derive input motions for dynamic FE analyses considering nonlinear elastoplastic materials.

Spectrum-optimized direct image reconstruction of super-resolution structured illumination microscopy

Super-resolution structured illumination microscopy (SR-SIM) has become a widely used nanoscopy technique for rapid, long-term, and multi-color imaging of live cells. Precise but troublesome determination of the illumination pattern parameters is a prerequisite for Wiener-deconvolution-based SR-SIM image reconstruction. Here, we present a direct reconstruction SIM algorithm (direct-SIM) with an initial spatial-domain reconstruction followed by frequency-domain spectrum optimization. Without any prior knowledge of illumination patterns and bypassing the artifact-sensitive Wiener deconvolution procedures, resolution-doubled SR images could be reconstructed by direct-SIM free of common artifacts, even for the raw images with large pattern variance in the field of view (FOV). Direct-SIM can be applied to previously difficult scenarios such as very sparse samples, periodic samples, very small FOV imaging, and stitched large FOV imaging.

Time domain deconvolution in nonlinear elastoplastic soil deposits

The paper presents an iterative procedure for the time domain deconvolution in nonlinear elastoplastic materials. The approach is intended for the generation of input motions for dynamic soil–structure interaction (DSSI) numerical analyses when the desired earthquake is specified at the surface of a nonlinear soil deposit. The main advantage is that the same constitutive model (or models) to be used in the DSSI simulation to characterise the soil deposit is also employed in the deconvolution procedure. Therefore, the desired surface motion is recovered from the free-field propagation of the resulting input motion at the base of the numerical model, accounting for the assumed constitutive behaviour of the ground. An application example is also presented, where the potential of the proposed approach is shown.

Combining Experimental and Theoretical Tools to Probe Radio-Oxidation Products in Polyethylene

Polyethylene is one of the most used polymers in a variety of sectors. A typical technique used to assess aging is infrared spectroscopy. Under oxidation, the region of the spectrum that is most studied is the one containing the carbonyl signature. However, various carbonyl groups contribute to the carbonyl peak: ketones, aldehydes, esters, lactones, carboxylic acids, and more. A usual procedure to quantify each of them is the deconvolution of experimental peaks based on experimental assignments of infrared bands. In this paper, we complement this procedure, applied to two polyethylene types, with extended density functional theory (DFT) calculations of infrared spectra, using a polyethylene model mimicking the main features of a semicrystalline polymer. We compare theoretical frequencies and infrared intensities with parameters extracted from the literature that are used to, eventually, estimate concentrations. We provide an alternative estimation entirely based on theoretical data, showing that DFT can be a valuable tool to analyze, or at least complement, experimental data to assess polymer aging. The comparison of different deconvolution procedures raises the question of the contribution of conjugated ketones in the global carbonyl buildup, as well as that of ketones/alcohols pairs, or the relative concentration of esters and aldehydes.

Investigating kinetic behavior and reaction mechanism on autothermal pyrolysis of polyethylene plastic

To reduce the energy supply for pyrolysis, autothermal pyrolysis is one of the most promising approaches to upcycle plastic waste. In this work, both single-step and multi-step methods were applied to perform kinetic studies of low-density polyethylene (LDPE) pyrolysis under oxidative atmospheres (0, 5, and 10% O2 balanced by N2) by changing the heating rate from 5 to 20 K min−1. Miura integral method was then used to estimate the apparent activation energy. The major findings showed that the multi-step method using asymmetric double sigmoidal (Asym2Sig) deconvolution procedure was more appropriate to study kinetic behaviors of LDPE autothermal pyrolysis. The activation energy needed for LDPE pyrolysis under N2 was 271 kJ·mol−1, while the activation energies of the three pseudo-reactions under 5% O2 were 71, 153 and 189 kJ·mol−1, and under 10% O2 were 74, 224 and 169 kJ·mol−1, indicating that LDPE autothermal pyrolysis was more energy-saving than conventional LDPE pyrolysis. Additionally, the reaction mechanism was proposed to provide an accurate and critical guideline for commercializing this novel technical route, which is beneficial to achieving sustainable plastic waste management and mitigating plastic pollution, simultaneously.

Peak deconvolution with significant noise suppression and stability using a facile numerical approach in Fourier space

The deconvolution problem for resolution and feature enhancement of analytical signals is known to be a noise-enhancing procedure to the extent that some authors have called it “violently unstable.” The sharpened result is frequently buried in high-amplitude noise in direct deconvolution using the Fourier division method. With a Gaussian deconvolving function, one can get a “Not-a-Number (NaN) error” due to division by near zero (complex) numbers in Fourier space. Herein, a simple numerical method that stabilizes the calculation of direct Fourier deconvolution and ensures that the noise is controlled is proposed. In this calculation, a small positive constant or symmetric positive peak function is added to the denominator during division in Fourier space, resulting in stability and high-frequency noise suppression. The key advantages of this non-iterative method are speed, numerical stability during division, noise suppression, peak area and location invariance, and minimization of the edge effects after deconvolution. Also, ringing effects in the baseline and negative overshoots are significantly mitigated using the modified denominator method. The numerical approach can be applied to enhance the analytical signals consisting of peaks, e.g., in NMR, IR, Raman spectroscopy, or separation sciences. Both symmetric and one-sided (asymmetric) broadening functions can be used for deconvolution in this method. Applications are also demonstrated for various test functions (square pulse, Voigt, or highly overlapped Gaussian peaks) with clear advantages with respect to the standard Fourier division method. The new denominator addition method is compared with two constrained deconvolution procedures in matrix formalism and Fourier domain.

Study of arsenic resonance spectral lines in far UV region from a HFEDL for usage in Zeeman absorption spectroscopy

This work is focused on obtaining and analyzing the main spectral characteristics of a high-frequency electrodeless light source filled with arsenic for use in high-precision atomic absorption analyzers. We analyzed the relative intensities of the three arsenic resonance spectral lines 189.0 nm, 193.7 nm, and 197.3 nm in the far UV spectral region, the dependence of the intensity on the applied voltage, the impact of the instrumental function on the emission spectra, the influence of self-absorption and the stability of the radiation. Among others, a deconvolution procedure was implemented to obtain the real shapes of the emitted profiles.

SiC/graphene-based test structures for the Kelvin probe microscopy instrumental function determination

The paper proposes a method for determining the instrumental function for measuring the surface potential in the Kelvin probe microscopy mode. The method is based on the use of SiC samples with regions of single-layer and double-layer graphene as a test structure. The measurement of potential profiles along different directions on such a surface makes it possible to determine the instrumental function for measurements of the potential. Using the instrumental function, one can perform a deconvolution procedure and restore the exact surface potential. Keywords: Scanning probe microscopy, Kelvin probe microscopy, deconvolution, graphene, silicon carbide.

Sooting tendencies of ethylene diffusion flame doped by C[formula omitted]-C[formula omitted] alcohols

The sooting propensity of steady laminar coflow ethylene/air flames is modified doping the fuel stream with vapors of alcohol and evaluated as a function of both the position of the alcohol function and the ramification level (linear/branched) of the molecule. To identify general trends, a range of 3 alcohol sizes (C3, C4, and C5) are compared: the 2 propanol isomers (primary and secondary), the 4 butanol isomers (2 primaries with 1 branched, 1 secondary, 1 tertiary), and 7 pentanol isomers (3 primaries with 2 branched, 3 secondary with 1 branched and 1 tertiary). Every alcohol has been injected as a doping vapor in the central tube of a Santoro’s burner. To evaluate the sooting tendencies, a Line-of-Sight Attenuation (LOSA) setup allows the extinction of a collimated laser beam operating at 645 nm to be measured yielding the field of local soot volume fraction fv. Two indicators are used and contrasted, i.e. one using integrated data (raw data from the camera capturing the laser extinction) and one using the local field (deconvoluted data). From these results, several conclusions can be drawn. The two indicators being in good agreement, it seems unnecessary to obtain local data to compare sooting tendencies at different conditions (for a given experimental setup). The noise from the deconvolution procedure can be drastically reduced by a classical image processing described precisely in the paper, i.e. an average filter. These results reveal a good correlation between alkene produced in rich premixed C2H4 flame. The sooting tendencies are consistent with the literature: linear molecule < branched molecule and primary alcohol < secondary alcohol < tertiary alcohol. Moreover, the number of carbon NC, here varied from 3 to 5, leads to a modification of the sooting tendency that is significantly narrower than that associated with the structure of the alcohol at a given NC.

Detection of the Biexciton of Monolayer WS2 in Ellipsometric Data: A Maximum‐Entropy Success

For nearly 50 years, the Burg/Andersen (BA) maximum‐entropy (ME) deconvolution procedure has been used to sharpen, and therefore accentuate, weak features in spectra, optical and otherwise. It is shown that the BA procedure can be further enhanced to yield even sharper features. Using this approach, the authors establish the existence of the biexciton in ellipsometric data of monolayer WS2 at 50 K, whereas differentiation and standard BA analysis cannot.

Co-pyrolysis of corn stover and waste tire: Pyrolysis behavior and kinetic study based on Fraser-Suzuki deconvolution procedure

Co-pyrolysis of biomass with waste tire, a hydrogen-rich material, can both improve the quality of bio-oil and mitigate the environmental issue caused by the disposal of waste tires. In this study, co-pyrolysis of corn stover and waste tire was firstly performed in a micro pyrolyzer, and positive synergistic effects were observed, promoting the production of hydrocarbon compounds. Additionally, the kinetics of co-pyrolysis of corn stover and waste tire were investigated. Due to the complexities of the co-pyrolysis process, the global process was divided into reactions of seven pseudo-components using the Fraser-Suzuki deconvolution function. The deconvolution results presented a good fit with experimental results. The activation energy of each pseudo-component was calculated using Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), and Friedman methods. Activation energy of each pseudo-component calculated from above mentioned methods did not greatly varied. Pseudo-component additives in waste tire with low thermal stability had the lowest activation energy (118.21–127.10 kJ/mol), and lignin in corn stover and synthetic rubbers (SR) in waste tire showed high activation energies since they are more thermally stable. The reaction mechanism was then determined using the master plot method. The results of the study are expected to provide more accurate basic information for further scale-up of the co-pyrolysis process.

Brewer's spent grain pyrolysis kinetics and evolved gas analysis for the sustainable phenolic compounds and fatty acids recovery potential

Within the presented paper, a thermochemical conversion via pyrolysis of spent grain from the local brewery (Alternatywa, Ruda Śląska, Poland) for phenolic compounds and fatty acids recovery is presented. Thermogravimetric pyrolysis was carried out at non-isothermal conditions (1, 2, and 4 K/min), under an inert N2 atmosphere. Deconvolution procedure for the kinetic modeling was implemented using own algorithm based on Gaussian function, using 3-stage kinetic mechanism, ascribed to the independent decomposition of the pseudo-components i.e., hemicellulose, cellulose, and bulk lignin-extractives. Released volatiles during pyrolysis was evaluated and recognized using gas chromatography-mass spectrometry and Fourier-transform infrared spectroscopy analysis, which confirmed the high content of fatty acids, phenolic compounds, and nitrogen compounds, with shares of 23.95%, 13.94%, and 25.10% respectively. Linkage of the desired product formations to the modeled kinetic stages of the BSG pyrolysis is a complex subject, and it is encouraged for future studies.