Two-step Technology Research Articles

Sequential use of a continuous-flow electrocoagulation reactor and a (photo)electro-Fenton recirculation system for the treatment of Acid Brown 14 diazo dye

The decolorization and TOC removal of solutions of Acid Brown 14 (AB14) diazo dye containing 50 mg L−1 of total organic carbon (TOC) have been first studied in a continuous-flow electrocoagulation (EC) reactor of 3 L capacity with Fe electrodes of ∼110 cm2 area each. Total loss of color with poor TOC removal was found in chloride, sulfate, and/or hydrogen carbonate matrices after 18 min of this treatment. The best performance was found using 5 anodes and 4 cathodes of Fe at 13.70 A and low liquid flow rate of 10 L h−1, in aerated 39.6 mM NaCl medium within a pH range of 4.0–10.0. The effluent obtained from EC was further treated by electro-Fenton (EF) using a 2.5 L pre-pilot flow plant, which was equipped with a filter-press cell comprising a Pt anode and an air-diffusion cathode for H2O2 electrogeneration. Operating with 0.10–1.0 mM Fe2+ as catalyst at pH 3.0 and 50 mA cm−2, a similar TOC removal of 68 % was found as maximal in chloride and sulfate media using the sequential EC-EF process. The EC-treated solutions were also treated by photoelectro-Fenton (PEF) employing a photoreactor with a 125 W UVA lamp. The sequential EC-PEF process yielded a much higher TOC reduction, close to 90 % and 97 % in chloride and sulfate media, respectively, due to the rapid photolysis of the final Fe(III)-carboxylate complexes. The formation of recalcitrant chloroderivatives from generated active chlorine limited the mineralization in the chloride matrix. For practical applications of this two-step technology, the high energy consumption of the UVA lamp in PEF could be reduced by using free sunlight.

Advanced technology for photocatalytic degradation of thiophanate-methyl: Degradation pathways, DFT calculations and embryotoxic potential

This study focuses on establishing an efficient two-step technology, which includes: (1) consecutive adsorption-desorption, using cellulose-based membranes, bCells, and (2) photocatalytic degradation of the fungicide thiophanate-methyl (TPM), using synthesized Ag-P25 and Ce-P25 catalysts. The catalysts, obtained by controlled deposition of Ag2O/Ag and CeO2 onto P25 TiO2 carrier (Degussa), were characterized using ATR-FTIR, XRPD, BET, FESEM, HRTEM, HAADF-EDS and UV–DRS techniques. In order to establish a feasible purification technology, preconcentration of TPM was performed by adsorption, achieving 75.5 and 92.9 mg/g of TPM removal using bCell-EpL and bCell–EpL–TA membranes, respectively, followed by efficient desorption (> 95%) that provided acceptable TPM concentration for photodegradation experiments. Under optimal conditions (0.07 g/L of both catalysts), complete degradation of TPM (5 mg/L) occurred within 2 h, compared to 4 h for the base TiO2 P25. Measurements of quantum yield and the results of HPLC-MS analysis, alongside DFT calculation, assisted in understanding the TPM degradation pathways. New degradation products were detected and proposed from HPLC–MS analysis. Embryotoxic assays, performed on zebrafish (Danio rerio), applied to estimate the toxicity evolution of time-dependent generated TPM degradation products, showed low embryotoxic potential. Chemical oxygen demand (26 mg O2/L) confirmed low ecotoxicological pressure of effluent water.

Novel thiol-grafted composite of chitosan and rice straw biochar (TH@CT-BC): A two-step fabrication for highly selective adsorption of cadmium from contaminated water

This study followed the one-step and two-step technologies to produce rice straw biochar (BC), chitosan-modified rice straw biochar (CT-BC), and thiol grafted chitosan-modified biochar (TH@CT-BC) for cadmium (Cd) removal from contaminated water. Here, chitosan and thiol were introduced by two-step combination to enhance the adsorption ability of biochar. Our results revealed the maximum Cd adsorption at pH 5.5 with TH@CT-BC (261.47 mg g−1) followed by CT-BC (103.14 mg g−1) and BC (29.64 mg g−1). Obtained data was best fitted by the Langmuir and pseudo-second-order kinetic models (with R2 values of 0.997 for TH@CT-BC) as compared to Freundlich and Temkin models (0.949 and 0.925, respectively). TH@CT-BC retained its efficiency in spiked river water system, removing up to 89% of Cd in river water spiked with 30 mg−1 L Cd. The experimental investigations and data calculations demonstrated the surface complexation and electrostatic interaction as dominant underlying mechanisms for Cd removal by TH@CT-BC. Moreover, it is essential to utilize the large amount of produced rice straw to develop new materials which would help in converting the waste to useable product for environmental remediation. Thus, this study demonstrates the production of TH@CT-BC from rice straw as an effective adsorbent of Cd from aqueous systems which can be studied as a potential candidate for practical wastewater treatment applications.

Perovskite-Based Solar Cells: Some Problems and Ways of their Solution

The fundamental aspects of the perovskite absorber formation of solar irradiation for two generally accepted one- and two-step technologies are considered. For the on-step variant, two stages of perovskite formation, called “through solution” and “intermediate colloid compounds of precursors”, were identified. The successive deposition of precursors is described in terms of thermodynamics and the Ostwald ripening model. The optimal conditions for the concentration and temperature for the spinning solution of methylammonium iodide to obtain various sizes of perovskite crystallites are presented. Examples are given for some other approaches that are used in the formation of high-quality perovskite films with high optoelectronic characteristics for a conversion rate of perovskite based solar cells on them.

Nanodroplet-Mediated Low-Energy Mechanical Ultrasound Surgery.

Mechanical ultrasound surgery methods use short, high-intensity pulses to fractionate tissues. This study reports the development of a two-step technology for low-energy mechanical ultrasound surgery of tissues using nanodroplets to reduce the pressure threshold. Step 1 consists of vaporizing the nanodroplets into gaseous microbubbles via megahertz ultrasound excitation. Then, low-frequency ultrasound is applied to the microbubbles, which turns them into therapeutic warheads that trigger potent mechanical effects in the surrounding tissue. The use of nanoscale nanodroplets coupled with low-frequency ultrasound reduces the pressure threshold required for mechanical ultrasound surgery by an order of magnitude. In addition, their average diameter of 300 nm can overcome challenges associated with the size of microbubbles. Optimization experiments were performed to determine the ultrasound parameters for nanodroplet vaporization and the subsequent microbubble implosion processes. Optimal vaporization was obtained when transmitting a 2-cycle excitation pulse at a center frequency of 5 MHz and a peak negative pressure of 4.1 MPa (mechanical index=1.8). Low-frequency insonation of the generated microbubbles at a center frequency of 850, 250 or 80 kHz caused enhanced contrast reduction at a center frequency of 80 kHz, compared with the other frequencies, while operating at the same mechanical index of 0.9. Nanodroplet-mediated insonation of ex vivo chicken liver samples generated mechanical damage. Low-frequency treatment at a mechanical index of 0.9 and a center frequency of 80 kHz induced the largest lesion area (average of 0.59 mm2) compared with 250- and 850-kHz treatments with the same mechanical index (average lesions areas of 0.29 and 0.19 mm2, respectively, p < 0.001). The two-step approach makes it possible to conduct both the vaporization and implosion stages at mechanical indices below 1.9, thus avoiding undesired mechanical damage. The findings indicate that coupled with low-frequency ultrasound, nanodroplets can be used for low-energy mechanical ultrasound surgery.

An Azimuth Signal-Reconstruction Method Based on Two-Step Projection Technology for Spaceborne Azimuth Multi-Channel High-Resolution and Wide-Swath SAR

Azimuth non-uniform signal-reconstruction is a critical step for azimuth multi-channel high-resolution wide-swath (HRWS) synthetic aperture radar (SAR) data processing. However, the received non-uniform signal has noise in the actual azimuth multi-channel SAR (MCSAR) operation, which leads to the serious reduction in the signal-to-noise ratio (SNR) of the results processed by a traditional reconstruction algorithm. Aiming to address the problem of reducing the SNR of the traditional reconstruction algorithm in the reconstruction of non-uniform signal with noise, a novel signal-reconstruction algorithm based on two-step projection technology (TSPT) for the MCSAR system is proposed in this paper. The key part of the TSPT algorithm consists of a two-step projection. The first projection is to project the given signal into the selected intermediate subspace, spanned by the integer conversion of the compact support kernel function. This process generates a set of sparse equations, which can be solved efficiently by using the sparse equation solver. The second key projection is to project the first projection result into the subspace of the known sampled signal. The secondary projection can be achieved with a digital linear translation invariant (LSI) filter and generate a uniformly spaced signal. As a result, compared with the traditional azimuth MCSAR signal-reconstruction algorithm, the proposed algorithm can improve SNR and reduce the azimuth ambiguity-signal-ratio (AASR). The processing results of simulated data and real raw data verify the effectiveness of the proposed algorithm.

Structure, electric and thermoelectric properties of binary ZnO-based ceramics doped with Fe and Co

We have studied the interconnection between structure (grain sizes, chemical and phase composition, porosity) and some electric properties (resistivity, Hall and Seebeck coefficients, as well as power factor, concentration and mobilities of carriers) in composite ceramics (ZnO)z[(TM)xOy]1-z (TM = Fe and Co – transition metals, 0 ≤ x ≤ 3; 1 ≤ y ≤ 4, 0.5 ≤ z ≤ 10 wt%), prepared by one-step and/or two-step annealing on air of powder mixtures of ZnO and TM oxides. The structure of ceramic samples was studied by X-ray diffraction (XRD), Mossbauer (MS) and Raman (RS) spectroscopies, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis and magnetometry. It was proved that phase composition of (ZnO)z[(TM)xOy]1-z ceramics depends on the type of doping agents. Addition of CoO to ZnO results in the formation of solid solutions with wurtzite structure after two-step annealing independently on Co concentration z ≤ 10 wt%. Addition of FexOy to ZnO results in the formation of the samples with three phase components after synthesis: submicron grains of wurtzute-like structure with large grains of ZnFe2O4 ferrite with spinel structure and residual oxides FexOy used as dopant in powder mixture. SEM measurements evidence that size of the wurtzite phase grains decreases from several tens of micrometers when using the one-step synthesis to a submicron level for the case of the two-step technology. Temperature dependences of electrical resistivity ρ(Т), as well as Hall and Seebeck coefficients in the undoped ZnO in th range of 6–500 K have shown a competition of the Mott and Shklovsky-Efros variable range hopping conductance (due to disordering), percolative one (due to formation of large-scaled potential relief) and a standard electron transport by Cband. It was found that Cband contribution to the carrier transport in ceramic samples (ZnO)z[(TM)xOy]1-z above 100 K was provided by both low and deep donor centers which have been formed in the wurtzite phase Zn1-δ(TM)δO. For example, in the TM doped samples we observed intrinsic shallow levels with ionization energies of about ΔE1 = (0.04–0.05) eV as well as extrinsic deep levels with ΔE2 = (0.24–0.37) eV. The iron doping of ZnO-based ceramic samples increased the room temperature Seebeck coefficient S(300 K) in average. In so doing, the S(300 K) dependence on electron concentration n of the studied samples (ZnO)z(FexOy)1-z approached maximal values (up to 1000 µV/K) at n = 1021 m−3. At the same time ZnO doping with Co resulted in more weak increase (up to 1.3–1.5 times) of S(300 K) values. Practically threefold growth of S(300 K) doe to Fe doping was attributed by us to the influence of particles of ferrite) formed in wurtzite matrix. The power factor P = (S2/ρ), estimated for the studied samples, evidenced that for both dopants it’s the highest values ( = 10−5 W/K·m) were approached in the (ZnO)z[(TM)xOy]1-z ceramics with the lowest resistivity values.

Abstract 2259: Single-cell multi-omics analysis of SNV, CNV, and protein expression

Abstract Recent advancements in precision medicine, while highly promising, presents a major technical challenge to researchers due to disease heterogeneity. The emergence of single-cell technologies has greatly refined the resolution in which sample diversity can be investigated, enhancing the efficiency of selecting appropriate molecular targets. Additionally, applying multi-omics analysis on single cells would further improve the understanding of cell-to-cell heterogeneity by providing unique insights on cellular and genetic composition. Using a two-step droplet microfluidic technology, the Mission Bio Tapestri Platform enables multiplex-PCR based high-throughput targeted DNA sequencing in single cells to obtain single-nucleotide variation (SNV) and copy number variation (CNV) information. By leveraging this technology, a new workflow is developed to detect protein expression in addition to DNA genotype in the same single cells. In this approach, cells are labeled with a pool of oligonucleotide-conjugated antibodies prior to loading the cells into the Tapestri Instrument. Sequencing libraries are then prepared from both antibody oligonucleotides and the amplified DNA sequences, followed by identification of single-cell DNA genotypes and protein signatures from the sequencing readout. The number of protein targets can be in the range from 6 to over 40, which is beyond the limit for a single flow cytometry run. This method has been successfully performed on cell lines, fresh and frozen PBMCs, as well as clinical samples. In an acute myeloid leukemia (AML) sample, combined single-cell SNV, CNV, and protein expression data illustrated the heterogeneity within the sample. The data clearly identified CD3+ T cells and CD19+ B cells without pathogenic SNVs and CNVs. CD34hiCD11blo and CD34loCD11bhi subpopulations were also identified within the cells carrying the same pathogenic SNVs and CNVs. We believe that this novel multi-omics technology will facilitate new discoveries in the complex relationship between genotype and phenotype, enable a better understanding of disease biology, and subsequently improve the design of diagnostics and therapies. Citation Format: Aik Ooi, Dalia Dhingra, Adam Sciambi, Kate Thompson, Jacqueline Marin, Saurabh Parikh, Mani Manivannan, David Ruff. Single-cell multi-omics analysis of SNV, CNV, and protein expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2259.

Extending FABRIK with Obstacle Avoidance for Solving the Inverse Kinematics Problem

Inverse kinematics (IK) has been extensively applied in the areas of robotics, computer animation, ergonomics, and gaming. Typically, IK determines the joint configurations of a robot model and achieves a desired end-effector position in robotics. Since forward and backward teaching inverse kinematics (FABRIK) is a forward and backward iterative method that finds updated joint positions by locating a point on a line instead of using angle rotations or matrices, it has the advantages of fast convergence, low computational cost, and visualizing realistic poses. However, the manipulators usually work in a complex environment. So, the kinematic chains are easy to produce the interference with their surrounding scenarios. To resolve the above mentioned problem, a two-step obstacle avoidance technology is proposed to extend the basic FABRIK in this study. The first step is a heuristic method that locates the updated linkage bar, the root joint, and the target position in a line, so that the interference can be eliminated in most cases. In the second step, multiple random rotation strategies are adopted to eliminate the interference that has not been eliminated in the first step. Experimental results have shown that the extending FABRIK has the obstacle avoidance ability.

Nutrient recovery from deammonification effluent in a pilot study using two-step reject water treatment technology

The aim of this study was to assess the possibility of phosphorus and nitrogen recovery from the liquid fraction of digestates (reject water) pilot study using a two-step technology, where the precipitation of biogenic compounds in the form of magnesium ammonium phosphate (struvite) will be preceded by a deammonification process.The tests confirmed the possibility of nutrient recovery from deammonification effluent. A removal efficiency from 85.0 to 92.0% of PO43− ions and from 13.0 to 21.0% of NH4+ ions in the form of magnesium salt was achieved, at a pH in the range of 8.7–9.0. However, when the pH value was from 9.1 to 9.3, phosphate ions were precipitated not only as magnesium salts, but also as calcium salts. The maximum struvite crystal sizes ranged from 0.72 to 1.65 mm, and was determined by the concentration of the suspended solids in the reject water, whose presence was a factor limiting the crystallization of struvite.

Structural and optical properties of Ag2S/SiO2 core/shell quantum dots

This paper presents an original two-step technology for water synthesis of Ag2S/SiO2 core/shell quantum dots (QDs) based on Ag2S QDs, passivated with thioglycolic acid with luminescence in the near IR region (800–1400 nm). The formation of Ag2S QDs with an average size of 2.5 nm, SiO2 coated with thickness of 1.3–4 nm has been established using transmission electron microscopy and energy dispersive X-ray analysis. The possibility to control the formation of Ag2S/SiO2 core/shell QDs using FTIR spectroscopy data is shown. The results show a change in the luminescence properties of Ag2S QDs with an increase in the thickness of SiO2 shell. They are i) an increase in the intensity and quantum yield of QD luminescence by 7 times during ligand exchange and up to 35 times as a result of a further increase in the thickness of SiO2 shell; ii) an increase in the average luminescence lifetime from 3.5 ns to 17.7 ns during the formation of SiO2 shell. These studies demonstrate a way to control the quantum yield of NIR recombination luminescence of colloidal Ag2S QDs and expand the ways of their application.

Assessment of a possibility to use 232U in radioisotope thermoelectric generators

The paper analyzes advantages and drawbacks of the radioisotope thermoelectric generators (RTG) based on application of 238Pu and 232U. Currently, the RTG on 238Pu are widely used for long-term autonomous power supply of spaceships due to the following positive properties of 238Pu: high specific heat generation rate, long half-life, weak emission of neutrons and γ-rays. Isotope 238Pu may be produced by neutron irradiation of 237Np (main component of transuranium radioactive wastes) in nuclear reactors. The paper considers application of 232U for the same purpose because of the following positive properties of 232U: power elevation during initial 10 years of the RTG operation (effect of α and β-emitters in 232U decay chain), long half-life (comparable with 238Pu half-life). Unfortunately, 232U decay chain includes also intense emitters of high-energy γ-rays. As a compromise, a possibility is considered to create the RTG based on mixture of 238Pu with small (below 5%) additive of 232U. Such RTG will be able to keep long-term stable operation at high power level. The following two-step technology is proposed to produce 232U: generation of 231Pa in thorium blanket of hybrid thermonuclear reactors and subsequent neutron irradiation of 231Pa in nuclear reactors till accumulation of significant 232U quantities.

Rapid densification of additive manufactured magnesium alloys via microwave sintering

Abstract Binder jetting provides a highly versatile two-step technology for additive manufacturing of difficult-to-process materials, including magnesium (Mg) alloys. Sintering in conventional (CT) furnaces has been extensively performed as the post-printing process to densify 3D printed parts, and exploring alternative sintering approaches is considerably lacking. The current study aimed to present a detailed comparative analysis of the consolidation of as-printed parts in CT and microwave (MW) furnaces. Accordingly, binderless 3D printed parts made of Mg-5.06Zn-0.15Zr powder were subjected to CT and MW sintering for various isothermal holding times and their physical, mechanical, and chemical properties, as well as sintering kinetics models, were thoroughly evaluated and compared. It was revealed that MW results in a three-fold reduction in sintering time compared to CT sintering counterparts. Supported by the analysis of sintering mechanisms, the MW sintering process is not merely governed by the thermal effect in a similar way to CT sintering, but the non-thermal phenomenon originating from the conversion of electromagnetic energy contributes substantially to the densification of 3D printed Mg parts by triggering the viscous flow mechanism. Furthermore, results indicated that the Mg sample sintered in MW for 15 h has an interconnected porous structure with comparable density, pores features, elastic modulus, and compressive strength to those found in human cortical bone types. Overall, this work enlightens the great potential of MW sintering as an attractive alternative to reduce the energy consumption and shorten the lead time of the binder jetting technology.

Abstract 5910: Single-cell multiomic analysis of SNV, CNV, and protein expression

Abstract Recent advancements in precision medicine, while highly promising, presents a major technical challenge to researchers due to disease heterogeneity. The emergence of single-cell technologies has greatly refined the resolution in which sample diversity can be investigated, enhancing the efficiency of selecting appropriate molecular targets. Additionally, applying multiomic analysis on single cells would further improve the understanding of cell-to-cell heterogeneity by providing unique insights on cellular and genetic composition. Using a two-step droplet microfluidic technology, the Mission Bio Tapestri Platform enables multiplex-PCR based high-throughput targeted DNA sequencing in single cells to obtain single-nucleotide variation (SNV) and copy number variation (CNV) information. By leveraging this technology, a new workflow is developed to detect protein expression in addition to DNA genotype in the same single cells. In this approach, cells are labeled with a pool of oligonucleotide-conjugated antibodies prior to loading the cells into the Tapestri Instrument for targeted DNA analysis. Sequencing libraries are then prepared from both antibody oligonucleotides and the amplified DNA sequences, followed by identification of single-cell DNA genotypes and protein signatures from the sequencing readout. In a mixed population of four cell lines, single-cell SNV and CNV information from 127 targeted amplicons and the protein data from 10 antibodies independently classified the cells into appropriate clusters. This method has been successfully performed on clinical samples with myeloid malignancies. In an acute myeloid leukemia (AML) sample, combined single-cell SNV, CNV, and protein expression data illustrated the heterogeneity within the sample. The data clearly identified CD3+ T cells and CD19+ B cells without pathogenic SNVs and CNVs. CD34hiCD11blo and CD34loCD11bhi subpopulations were also identified within the cells carrying the same pathogenic SNVs and CNVs. We believe that this novel multiomic technology will enable new discoveries in the complex relationship between genotype and phenotype, leading to a better understanding of disease biology, and subsequently better design of diagnostics and therapies. Citation Format: Aik Ooi, Pedro Mendez, Dalia Dhingra, Nigel Beard, David Ruff. Single-cell multiomic analysis of SNV, CNV, and protein expression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5910.

Preparation of a Ceramic Matrix Composite Made of Hydroxyapatite Nanoparticles and Polylactic Acid by Consolidation of Composite Granules.

Composites made of a biodegradable polymer, e.g., polylactic acid (PLA) and hydroxyapatite nanoparticles (HAP NPs) are promising orthopedic materials. There is a particular need for biodegradable hybrid nanocomposites with strong mechanical properties. However, obtaining such composites is challenging, since nanoparticles tend to agglomerate, and it is difficult to achieve good bonding between the hydrophilic ceramic and the hydrophobic polymer. This paper describes a two-step technology for obtaining a ceramic matrix composite. The first step is the preparation of composite granules. The granules are obtained by infiltration of porous granules of HAP NPs with PLA through high-pressure infiltration. The homogeneous ceramic-polymer granules are 80 μm in diameter, and the composite granules are 80 wt% HAP NPs. The second step is consolidation of the granules using high pressure. This is performed in three variants: Uniaxial pressing with the pressure of up to 1000 MPa at room temperature, warm isostatic compaction (75 MPa at 155 °C), and a combination of the two methods. The combined methods result in the highest densification (99%) and strongest mechanical properties; the compressive strength is 374 MPa. The structure of the ceramic matrix composite is homogeneous. Good adhesion between the inorganic and the organic component is observable using scanning electron microscopy.

Rapidly Separating Earthworm from Vermicompost Using Two-Step Technology

The vermicomposting has become a widely accepted approach to dispose organic solid waste such as livestock manure, plant straw and municipal sludge. With the enlargement of vermicomposting scale, it is necessary to separate earthworm from vermicompost as soon as possible before marketing. However, nowadays, separating earthworm is a bottle-neck in vermicomposting industry because it is often done manually, which is inefficient and expensive. The objective of this study is to develop a rapid and highly efficient two-step technology of separating earthworm from large-scale vermicompost. During the separation process, small granule vermicompost (diameter size < 6 mm) were separated with rolling screen and the earthworm were thoroughly separated from vermicompost through a special cone structure equipment called conical separator. Three experiments were conducted to evaluate the separation efficiency and obtain the optimal parameters for Earthworm-Vermicompost Rolling Separator (EVRS). The results showed that the optimal parameters for the EVRS were as follows: screen mesh size was 6 mm, rolling speed was 33.05 r min−1, inclined angle of rolling screen was 6.40°, screening length of rolling screen was 1290 mm and the generatrix angle of conical separator was 28°. The optimal separation effect could be achieved for EVRS at 45–55% vermicompost moisture content. Ten kg earthworm and vermicompost mixture was treated within 41.55 s, consuming electric power in 0.0025 kWh. EVRS can separate 84.38 ± 3.20% of mature earthworm and earthworm can be separated with survival rate of 96.25 ± 2.50%. In this study, the developed two-step technology and separator is a rapid, less energy consumption, highly efficient and applicable, which is expected to lighten the labor burden and shorten the recycling time of vermicomposting product.

Continuous production of multicomponent powder mixtures

Mixing of powders is an important process in various industries, from chemical, pharmaceutical to food and construction. The main characteristic of the mixture is its homogeneity, which is usually estimated by the coefficient variation and the lower this ratio, the better the mixture. Typically, particles of the components of the mixture differ in size and / or density. These differences cause segregation, i.e. the formation of zones in which there is a high concentration of one of the components and this affects the quality of the mixture. However, through the use of special technological methods, the negative result of segregation can be transformed into a positive one and not only reduce the mixing time, but also improve the quality of the mixture. This article discusses one of the options for the production of a multicomponent mixture with a specific schedule for loading components. It is shown that by organizing the correct sequence of loading components, you can control the mixing process. Two-step technology is used to feed components into the mixer.

A New Reservoir Protection Technology for Offshore Condensate Gas Wells during Shut-in

Wells in tight sandstone condensate gas reservoirs of East China Sea often suffer from dramatic production declines after being closed for several days. The closure can be caused by typhoon. For example, the gas production of target well B1, studied in this paper plummeted from 50,000 to 0 m3/d after the typhoon. This study aims to propose a reservoir protection technology preventing the offshore condensate gas wells from production decline caused by emergent shut-in operations. Firstly, based on comprehensive analysis of the production parameters, experimental data, and process mechanism, it was shown that the sudden drop in gas production of well B1, is attributed to wellbore liquid loading and reservoir liquid locking damage and is not caused by the insufficient recoverable reserves and solid plugging damage. Secondly, a liquid locking removal technology combining wettability alteration treatment with coiled tubing gas technique was proposed and applied on the well B1. The result showed that the gas production increased dramatically from 0 to 40,000 m3/d. However, even though the liquid locking removal technology proved to be efficient, it is also time-consuming and costly. Therefore, in order to optimize the construction time and costs for the conditions of the actual offshore production, an improved innovative two-step reservoir protection technology was suggested, combining foam drainage gas recovery and wettability alteration treatment.

Fabrication, mechanical properties and thermal shock resistance of a dense SiC NWs/α-Si3N4 composite coating for protecting porous Si3N4 ceramics

To prevent porous Si3N4 ceramics from absorbing moisture in practical application, a dense SiC NWs/α-Si3N4 composite coating was fabricated using the two-step technology involving slurry and liquid infiltration method. The results revealed that the SiC NWs not only can promote densification sintering of the coating but also can reduce thickness of the coating effectively due to the block effect of the SiC NWs. Furthermore, the SiC NWs in the coating had a good interfacial bonding with α-Si3N4 matrix, meanwhile the toughening effects of the SiC NWs involving crack deflection, crack branching, SiC NWs bridging and pullout, also presented during mechanical damage. The strengthening and toughening mechanisms of the SiC NWs not only enhanced mechanical properties of the coating but also raised significantly critical crack size (L), thereby which made the coating have a good ability for thermal shock resistance. After thermal shock at ΔT = 1000 °C for 15 times, water absorption of the coated porous Si3N4 ceramics increased only to 7.21% from 4.54%, and its residual strength ratio was up to 83.4%. More importantly, the coating exhibited an ability for crack healing during thermal shock testing. All those above results indicated that as-prepared SiC NWs/α-Si3N4 composite coating can meet the applied requirements in long-term extreme conditions.

Improved performance of Al/n&lt;sup&gt;+&lt;/sup&gt;Ge Ohmic contact andGe n&lt;sup&gt;+&lt;/sup&gt;/p diode by two-step annealing method

Silicon based germanium devices are crucial parts of optoelectronic integration as CMOS feature size continuously decreases. Germanium has attracted increasing attention due to its higher electron and hole mobility, larger optical absorption coefficient as well as lower processing temperature than those of silicon. However, the high diffusion coefficient and low solid solubility about n-type dopant and relatively high thermal budget required for high n-type doping in Ge make it difficult to achieve high activation n-type doping and excellent n&lt;sup&gt;+&lt;/sup&gt;/p shallow junction for source/drain in the nano-scaled n-MOSFET (here MOSFET stands for). The high activation concentration and shallow junction n-type doping in Ge are greatly beneficial to the scaled Ge n-MOSFET technology. In this work, the ohmic contact of Al/n&lt;sup&gt;+&lt;/sup&gt;Ge and Ge n&lt;sup&gt;+&lt;/sup&gt;/p junction fabricated by a combination of low temperature pre-annealing process and excimer laser annealing for phosphorus-implanted germanium are demonstrated. Prior to excimer laser annealing, the samplesare annealed at a relatively low temperature, which can heal the implantation damages preliminarily. Through the optimization of pre-annealing temperature and time, the low temperature pre-annealing step can play a critical role in annihilating the implantation damages and significantly suppressing phosphorus diffusion in the laser annealing process, resulting in a very small dopant diffusion length at a high activation level of phosphorus. Through the combination of ion implantation and two-step annealing technology, the specific contact resistivity (&lt;i&gt;ρ&lt;/i&gt;&lt;sub&gt;C&lt;/sub&gt;) of Al/n&lt;sup&gt;+&lt;/sup&gt;Ge Ohmic contact is measured by CTLM structure. The optimized annealing condition is 400 &lt;sup&gt;o&lt;/sup&gt;C-10 min of low temperature annealing and 150 mJ/cm&lt;sup&gt;2&lt;/sup&gt; of ELA. Under that annealing condition, the ρ&lt;sub&gt;C&lt;/sub&gt; of the sample by two-step annealing is reduced to 2.61 × 10&lt;sup&gt;–6&lt;/sup&gt; Ω·cm&lt;sup&gt;2&lt;/sup&gt;, which is one order of magnitude lower than that by ELA alone (about 3.44 × 10&lt;sup&gt;–4&lt;/sup&gt; Ω·cm&lt;sup&gt;2&lt;/sup&gt;). The lower value of &lt;i&gt;ρ&lt;/i&gt;&lt;sub&gt;C&lt;/sub&gt; for the sample with LTPA can contribute to the higher carrier concentration and better crystalline quality thanthat without LTPA, which is confirmed by SRP and TEM. Moreover, the rectification ratio of Ge n&lt;sup&gt;+&lt;/sup&gt;/p junction diode is improved to 8.35 × 10&lt;sup&gt;6&lt;/sup&gt; at ± 1 V, which is two orders of magnitudes higher than that by ELA alone. And a lower ideality factor of about 1.07 is also obtained than that by ELA alone, which indicates that the implantation damages can be repaired perfectly by two-step annealing method.