Transformation Ratio Research Articles

Combined partial denitrification-anammox with urea hydrolysis (U-PD-Anammox) process: A novel economical low-carbon method for nitrate-containing wastewater treatment

For the sake of exploring a new economical and low-carbon alternative for real nitrate-containing wastewater treatment, a new combined partial denitrification-anammox with urea hydrolysis (U-PD-Anammox) process was developed. The nitrogen removal performance of this process was investigated through long-term operation in a sequencing batch reactor (SBR) and two submerged anaerobic biological filters (SABF). Results showed that the average NO3−-N to NO2–N transformation ratio improved to 82.6% with organic carbon source to NO3–N ratio of 1.8, and urea hydrolysis provided sufficient NH4+-N and inorganic carbon to anammox process for nitrogen removal. The influent NH4+-N/NO2−-N ratio for subsequent anammox reactor could be adjacent to the optimal ratio of 1.32 during the whole operation. The combined process showed efficient nitrogen removal performance with 85% NO3−-N removal, 93.8% total nitrogen removal and total nitrogen loading rate as 1.1 ± 0.5 kg N/(m3·d). High-throughput sequencing analysis results revealed that Genera Thauera, Hyphomicrobium and Candidatus Brocadia were the dominant species responsible for partial denitrification, urea hydrolysis and anammox, respectively. The proposed process was more economically and environmental-friendly than the traditional denitrification process with 51.7% operational cost reduction, 99.7% N2O and 60% CO2 emission decrement, facilitating the sustainable development of the nitrate-containing wastewater treatment industry in the future.

Evaluation, design, and test of single switch high step‐up boost converter with autotransformer

SummaryIn this article, different autotransformer structures are discussed, demonstrating their connection and voltage gain characteristics. In this sense, an autotransformer structure was chosen that presents a high voltage gain with a low transformation ratio (N), thus seeking to reduce the leakage inductance and volume. From there, this structure is integrated into the isolated boost converter, thus generating a new high step‐up DC‐DC topology. The proposed converter presents as main characteristics: high voltage gain, low voltage stress on the components, continuous input current, low number of components, simplicity of operation and control, and high efficiency. To validate the theoretical evaluations, a 200 W, 30 V/400 V prototype was built in the laboratory, achieving a maximum efficiency of 96.25%.

Geochemical, mineralogical and petrographical characteristics of the domanik formation from north samara region in the volga-ural basin, Russia: Implication for unconventional tight oil reservoir potential

This paper comprehensively analyzes the geochemical, mineralogical and petrographical properties combined with bulk kinetics modeling of the Domanik organic-rich carbonate from various depth intervals in Kuzminovsky oilfield (well № 26 R), Volga-Ural Basin, Russia. The results show that, the Domanik carbonate-rich samples are characterized by high content of the total organic matter (TOC) up to 13.31 wt %, and contain mainly Type II kerogen with a slight II/III kerogen type, reaching very good to excellent oil generation potential. Moreover, the studied samples contain hydrogen-rich kerogen, which expected to generate paraffin, naphthene and aromatic (P–N-A) oil with low wax content as demonstrated by the Py-GC Pyrolysis combined with the abundance of fluorescent alginite, amorphous organic matter, and bituminite as established from investigations via microscope. The maturity indicators demonstrated that, most of the examined Domanik carbonate-rich samples, with a burial depth between 1726.5 m and 1784.9 m, have generally reached low thermal maturity stages; thus, defining an immature to moderate-mature of oil generation window. The results of the kinetic models suggested that, Domanik carbonate-rich rocks with vitrinite reflectance (VRo) values in the range of 0.60–0.71%, have reached relatively low kerogen transformation ratio in the range of 10–20%, indicating low probability oil generation. These finding are confirmed by the presence of low oil saturation index of less than 100 mg HC/g rock (19.64–69.97). In addition, the results of thin section, scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) showed that the studied samples are characterized by low porosity (up to 3.29%) with a wide pores size range, including interparticle, cavities, cracks and organic matter pores. The development of these pore types and their quality in the studied samples is mainly controlled by high mineralogical brittleness (i.e., carbonate and quartz) together with the high organic matter inputs. Therefore, according to the obtained results, characteristics and observations, the Domanik Formation has a high potential for commercial oil production, which typically requires hydraulic fracturing followed by an in-situ retort, mainly by thermal methods such as steam injection and in situ combustion process.

Hydraulic fracturing as unconventional production potential for the organic-rich carbonate reservoir rocks in the Abu El Gharadig Field, north western Desert (Egypt): Evidence from combined organic geochemical, petrophysical and bulk kinetics modeling results

This paper systematically analyzes the organic geochemical, petrophysical, and petrographical properties combined with bulk kinetics modeling of the Abu Roash (F) organic-rich carbonate rocks in the Abu El Gharadig Field. The Abu Roash (F) carbonate-rich samples exhibit high organic content with total organic matter (TOC) values up to 3.04 wt%, and mainly Type II kerogen, with a slight gradient to Type II/III and III kerogens, reaching good to very good oil generation potential. This finding of hydrogen-rich kerogen and oil generation potential was also demonstrated by the abundance of fluorescent alginite, amorphous organic matter (AOM), and bituminite organic matter (OM) as established via ultra violet (UV) light microscopy. The maturity indicators demonstrate that most of the examined Abu Roash (F) carbonate-rich samples from the studied wells, with a deep burial depth of more than 3000 m, are thermally mature, thus defining an early mature to moderate-mature stage. The kinetic models suggest that the Abu Roash (F) carbonate-rich rocks in the deepest burial depth, with calculated vitrinite reflectance (%VRo) values in the range of 0.72–0.83 %, have reached kerogen transformation ratio (TR) in the range of 10–55 %, indicating a high probability of oil production. This finding is confirmed by the presence of the oil crossover in these rocks with an oil saturation index (OSI) of more than 100 mg HC/ g rock. The Abu Roash (F) organic-rich carbonates are intractable rocks as implied by low porosities (up to 2.33 %) and poor permeability in the range of 0.0017–0.0039 mD. The pores in these rocks have a wide range in size, including interparticle, fracture, and organic matter (OM) pores, as recognized in the thin section and scanning electron microscopy (SEM). The development of these pore types and their quality is mainly controlled by high mineralogical brittleness (i.e., carbonates) together with the high OM inputs. Based on the above characteristics, the Abu Roash (F) carbonate-rich rocks in the Abu El Gharadig Field are a candidate for unconventional tight oil reservoir potential, which typically require a form of hydraulic fracturing for possible oil production at deeper burial depths.

Zexie Decoction regulates Akt/TFEB signaling pathway to promote lipophagy in hepatocytes

Taking lipophagy as the breakthrough point, we explored the mechanism of Zexie Decoction(ZXD) in improving lipid metabolism in the hepatocyte model induced by palmitic acid(PA) and in the animal model induced by high-fat diet(HFD) on the basis of protein kinase B(Akt)/transcription factor EB(TFEB) signaling pathway. Co-localization was carried out for the microtubule-associated protein light chain 3(LC3) plasmid labeled with green fluorescent protein(GFP) and lipid droplets(LDs), and immunofluorescence co-localization for liver LC3 of HFD mice and perilipin 2(PLIN2). The results showed that ZXD up-regulated the expression of LC3, reduced lipid accumulation in hepatocytes, and increased the co-localization of LC3 and LDs, thereby activating lipo-phagy. Western blot results confirmed that ZXD increased autophagy-related protein LC3Ⅱ/LC3Ⅰ transformation ratio and lysosome-associated membrane protein 2(LAMP2) in vivo and in vitro and promoted the degradation of sequestosome-1(SQSTM1/p62)(P<0.05). The results above jointly explained that ZXD regulated lipophagy. Furthermore, ZXD activated TFEB expression(P<0.05) and reversed the PA-and HFD-induced decrease of TFEB nuclear localization in hepatocytes(P<0.05). Meanwhile, ZXD activated liver TFEB to up-regulate the expression of the targets Lamp2, Lc3 B, Bcl2, and Atg5(P<0.05). Additionally, ZXD down-regulated the protein level of p-Akt upstream of TFEB in vivo and in vitro. In conclusion, ZXD may promote lipophagy by regulating the Akt/TFEB pathway.

Variable Saturation Inductor-Based Full Bridge Converter With Wide ZVS Range and Reduced Duty Cycle Loss

A phase-shifted full-bridge (PSFB) converter is widely used in various applications due to its soft-switching characteristics. However, one of the recognized shortcomings of the PSFB converter is that it cannot simultaneously have a wide soft switching range and a small secondary-side duty cycle loss. The shortcoming hinders the high frequency and high efficiency of the converter. In this article, the change of the energy demand of the converter on the external series inductor with input voltage and load is analyzed. On this basis, a variable saturation inductor with controllable energy is proposed to meet the energy demand and solve the problem of core heating. The controllable change characteristics of the inductor energy are studied directly instead of the controllable change of the inductance value. By adjusting the inductor energy, the PSFB can not only achieve soft switching under light loads, but also reduce duty cycle loss under heavy loads. Theoretical analysis and experimental verification are carried out on the soft switching and duty cycle loss of the converter. Since the transformer ratio can be increased due to thesmaller duty cycle loss. The efficiency of the converter can be further improved.

Transformation of 2, 4, 6-trinitrotoluene by Stenotrophomonas strain SG1 under aerobic and anaerobic conditions

TNT, or 2,4,6-trinitrotoluene, is a common explosive that can contaminate soil and groundwater in production sites, military training areas, and disposal locations. The compound is highly toxic; therefore, there is an urgent need to rehabilitate the impacted environments. Harnessing the microbial ability to biodegrade TNT into environmentally harmless compound(s) is one approach to remediating contaminated sites. In our study, we report on the genomic and metabolic ability of Stenotrophomonas strain SG1 to degrade TNT under aerobic and anaerobic conditions. The bacterial strain SG1 was first isolated as a contaminant from a culture of Diaphorobacter sp. strain DS2 over minimal media supplemented with TNT. The draft genome assembly of strain SG1 is ∼4.7 Mb and is distributed among 358 contigs. The homology search against the custom database of enzymes responsible for TNT biodegradation revealed the presence of three N-ethylmaleimide reductases (NemA) with a defined KEGG ortholog and KEGG pathway of TNT degradation. The presence of respiratory nitrate reductases has also been mapped, which supports denitrification under anaerobic conditions. Experimentally, the TNT transformation rate accelerated when carbon sources, such as sodium acetate, sodium citrate, sodium succinate, sucrose, and glucose (final concentration of 5 mM), were added. Citrate promoted the highest growth and TNT transformation ratio (88.35%) in 120 h. With the addition of 5 mM ammonium chloride, TNT completely disappeared in the citrate and sucrose-containing treatments in 120 h. However, higher biomass was obtained in the sucrose and glucose-containing treatments in 120 h. During incubation, the formation of amino dinitrotoluene isomers, dinitrotoluene isomers, trinitrobenzene, azoxy isomers, diaryl hydroxylamines, and corresponding secondary amines was confirmed by GC/MS and UPLC/MS. 2-Amino-4-nitrotoluene, 4-amino-2-nitrotoluene, and 2-amino-6-nitrotoluene were also identified in the culture supernatant by GC/MS. Under anaerobic conditions, TNT completely disappeared in the citrate and citrate plus nitrate treatments. Since the strain shows the ability to remove TNT, this research should be useful in basic research and practical applications for removing TNT from wastewater.

Determining the static characteristic of a measuring current transformer at a reduced load of the metering unit

The object of the research is a measuring current transformer of the electromagnetic type, which is used as part of the electricity metering unit. The current transformers functioning in the mode of reduced primary current is accompanied by significant errors. The existence of such a regime for a long time due to downtime of production equipment leads to a significant underestimation of electricity. This leads to unjustified financial losses for energy supply companies as electricity in many countries has become more expensive. The static characteristic of the measuring current transformer at a reduced load of the metering unit is described by a linear statistical model. The parameters of the model are estimated on the basis of empirical data using methods of covariance analysis. The adequacy of the model is confirmed by analysis of regression residuals. The obtained statistical model of the static characteristic, unlike the known ones, is characterized by universality, as it describes current transformers with an arbitrary transformation ratio within the studied accuracy class of 0.5S. The uncertainty of the current error is estimated using the prediction intervals for the transformers secondary currents as a function of the primary currents, calculated on the basis of the obtained model. The prediction intervals for sample values of the current error were obtained through the application of the proposed approach for uncertainty estimation of such an error at a reduced load of the metering unit. It was found that the current error can reach −20 %. Taking into account the indicated intervals for measuring current transformers at a reduced load of the metering unit during billing will allow energy supply companies to increase the accuracy of commercial electricity metering.

High transformer ratio electron acceleration for CEPC plasma injector

The CEPC Plasma Injector is designed as the beam energy multiplier for avoiding the dipole magnet issue of the Circular Electron Positron Collider (CEPC) booster. Besides the final energy, other requirements including the energy stability, bunch charge and energy spread all make the injector design very challenging. With respect to the electron acceleration, a high transformer ratio plasma wakefield acceleration stage is necessary if we constrain the beam energy at the end of the linac and the plasma injector are 10[Formula: see text]GeV and 45.5[Formula: see text]GeV, respectively. In this work, we use the particle-in-cell code QuickPIC to design the electron acceleration stage. Based on the current conceptual design, a comprehensive analysis of single-parameter tolerance is performed. Through the tolerance studies, we obtain some useful guidance for the further optimization of the injector.

Metagenomics-based interpretation of selective bioaugmentation promoting partial-denitrification coupling with anammox process reactivation in suspended sludge system

The partial-denitrification coupled to anammox process (PD/A) has been emerging as a potential alternative for cost-efficient nitrogen removal from wastewater. Although there has been intensive study on startup and optimization, efficient reactivation and controlling strategy after disturbance of this process still lack essential information. Here, a selective bioaugmentation strategy with low dosage for stepwise recovery of PD and anammox activity were proposed and demonstrated for the first time, and the mechanism of coupling process reactivation was revealed based on metagenomic analysis. A significant increase in nitrite (NO2-N) production was obtained after introducing PD inoculum by weight ratio of 7.7 %, with nitrate (NO3−-N)-to-NO2−-N transformation ratio (NTR) increasing from 15.7 % to 45.0 %, while anammox activity stayed at a relatively low level. The ammonia (NH4+-N) removal rate significantly increased by 4.0 times after supplying PD/A biomass by only 1.2 % due to sufficient substrate NO2−-N for anammox. Consequently, nitrogen removal efficiency was remarkably improved to 99.2 % and kept stable with low-strength wastewater. Metagenomics analysis revealed that the abundances of genes nar and nap encoding NO3−-N reductase were kept at much higher level than nir for NO2−-N reductase. Significantly, higher diversity and abundance of genes responsible for carbon metabolism could accelerate the electron generation and transfer to PD, thus stimulating anammox activity, which was the key reason for the rapid reactivation of PD/A process. Furthermore, the substate ratio, nitrogen loading rates and morphological characteristics of sludge have crucial influence on the recovery of biomass activity. The dominant genus Thauera responsible for PD and Candidatus Brocadia for anammox coexisted stably after bioaugmentation. These results provide a comprehensive understanding of reactivating and regulating a novel PD/A process towards application and microbial interaction.

Bidirectional field–circuit coupling analysis of converter transformer inter‐tap short‐circuit faults in on‐load tap changers

Converter transformer inter-tap short-circuit faults in on-load tap changers have occurred successively in recent years, resulting in severe accidents and enormous losses. Due to the lack of an effective model and credible arc-in-oil conductance parameters, related fault analysis has remained a challenge. This paper develops a bidirectional field–circuit coupling method for modelling inter-tap faults, in which the electromagnetic field and electric circuit are directly coupled and simultaneously solved. After verification based on on-site arcing tests, the Schavemaker model is applied to calculate the non-linear arc conductance. Taking a ±800 kV UHVDC system as a study case, inter-tap faults in a 415 MVA/500 kV converter transformer are simulated and analysed. Under an inter-tap fault, the flux distribution is significantly distorted, with large radial leakage fluxes near the shorted turns, and the circulating current can reach tens or even hundreds of kiloamperes. Further calculation results for faults between various taps indicate that leakage flux distortion and the change in the transformation ratio are the main factors influencing the short-circuit current. These representative findings effectively reveal the variation characteristics of the leakage flux and the short-circuit current as well as the non-linear relationship between fault severity and tap position under inter-tap faults.

(Digital Presentation) Sub-THz Front Ends for Future Communication and Sensing Technologies in 130nm Sige Bicmos Technology

Introduction: Beyond the-5G technologies are targeting the available bandwidth (BW) in the D-band and J-band. This promises for very high speed communication and sensing accuracy. Although the advantages of operating beyond 100 GHz from the application point of view, it requires a lot of research and development to design a reliable and power efficient chipsets. In this presentation we will go through the design of wideband 240 GHz transmitter (Tx) and receiver (Rx). Firstly an overview about the link budget analysis will be given, then the design of the local carrier signal generator will be discussed. The wideband Txs and Rxs are to be presented with frequency channelizing concept. At the end the results of the wireless links will be demonstrated. Link Budget Analysis: Operating at sub-THz frequencies approaching the transistor fT put a lot of constraints on the system link budget. The elevated noise figure together with the limited maximum Pout of the transistors lead to solutions which might be limited in BW or power efficiency. Hence the design architecture need to be optimized taking into account the elevated power consumption and heat dissipation. Carrier Generation: Several approaches could be followed to generate the sub-THz carrier frequency. For a power efficient solution the fundamental oscillators promise for a power efficient solution but with limited phase noise performance and tuning range. Such a solution is more common for imaging systems operating at a single frequency. In order to achieve wider tuning ranges for multi-channel scenario or FMCW radar systems, the frequency multiplication chains are common, whereas the multiplication factor depends on the system parameters. Sub-THz Rx: Different approaches were followed to realize a wideband sub-THz Rx. For some technologies the transistors ft does not promise the realization of low noise amplifiers (LNA) with reasonable noise figure, gain and BW. Hence the mixer first approach were followed trying to optimize the noise figure of the down conversion mixer as much as possible. This also enhances the input compression point (IP1dB) of the Rx which is better for monostatic radar applications. On the other hand, if the technology in use allows the development of well performing LNA’s, the LNA first approach was followed to enhance the all over NF of the receiver and ease the implementation of IQ Rxs. In our work an LNA was implemented followed by IQ downconversion mixers and baseband chain as presented in [3]. Sub-THz Tx: The Tx main challenging performance parameter in the sub-THz frequency range is to achieve high output compression point across the required BW with as high efficiency as possible. Increasing the power handling capabilities of the power amplifiers (PA) by increasing the transistors sizes of the output stages, leads to low output impedance and hence higher impedance transformation ratios for the matching structures and eventually narrow band designs. Hence the power combining architectures were proposed as an alternative to increase the output power either by combining on-chip or combining in air. In this work a fully integrated IQ Tx is to be presented with on-chip LO chain and 4-way power combined power amplifier. Baseband Signal Generation and Processing The baseband topology depend on the application. For mobile communication or localization use cases a wideband channels are not available directly from the digital processors, a kind of channel bonding is required either in the digital domain or in the analog domain. As a proof of concept we present here 3-IQ frequency interleaving combiner. Wireless Link Demonstrator Two demonstrators are to be presented. The first demonstrator is transmitting a broadband IQ signal generated from an arbitrary wave generator wirelessly utilizing an IQ 240GHz Tx and Rx. Data rates up to 100 Gbps were demonstrated across a 1m of wireless link. The second demonstrator includes the implementation of 3-channel IQ channelizer to create the complex modulated signal at several intermediate frequencies (IFs) and then upconverted to the 240GHz carrier signal. On the Rx side the de-channelizer convert the down modulated signal to three IQ channels. Data rates up to 8Gbps were demonstrated wirelessly with the channelization with potential of further enhancements for more channels integration. Outlook The future of the sub-THz wireless links for high speed communication and localizations goes towards implementing phased array and MIMO systems. This requires the research community to develop novel architectures to develop large scale arrays with acceptable power consumptions and suitable packaging solution. On the baseband side also the channel bonding solutions are still in an early stage, requiring more work to bond modularly larger number of channels.

Development of measures to reduce grid energy losses in the Namangan Region of Uzbekistan

The paper is aimed at developing technical and organizational measures to reduce the losses of electrical energy during its transmission via main and distribution electrical grids, in power transformers and electric power trans-mission lines. The focus of the study was on electrical grid modes in the Namangan Region of Uzbekistan (voltages of 220/110/35/10/6 kV), which were analyzed via technological calculation-based research methods using an equivalent circuit representing the linear circuit currently employed in the regional electric energy system. In addition, electrical grids were simulated using the software package “Program for calculating electrical grid modes” followed by the processing of calculation results by means of the Microsoft Excel package. The paper calculates electrical modes for the equivalent circuit of the regional electric energy system, as well as offering technical measures (installation of reactive power compensation devices; adjustment of transformation ratios in power transformers) aimed at adjusting voltage to improve electric power quality in terms of voltage deviations and lower power losses. Voltage deviations in most grid nodes were found to be inconsistent with GOST 32144-2013. Thus, in 35 kV, 10 kV, and 6 kV nodes, the largest underdeviation amounted to 12.45 kV, 3.26 kV, and 2.09 kV, respectively. For the placement of reactive power compensating devices having a total power of 67.82 MV∙Ar, 35 kV nodes were used; in addition, the values of transformer ratios at transformer substations (35–110 kV) were determined. Calculations indicate that the conducted activities can normalize voltage in the 35 kV, 10 kV, and 6 kV nodes while reducing power losses in the electrical grid by 9.35 MW. It is estimated that the proposed measures will be paid back in approximately three years. By means of compensating reactive power and adjusting transformer ratios, these measures can reduce electrical energy losses during transmission in the considered objects and maintain a given voltage level.

Organic geochemical characteristics and hydrocarbon generation mechanism of marine-continental transitional organic-rich shale: A case study from the Shanxi formation in the eastern margin of the Ordos Basin

Previous research and exploration has shown that China has abundant marine-continental transitional shale gas resources. Favourable areas are widely distributed, and are mainly in the Carboniferous-Permian strata. However, the organic geochemical characteristics and hydrocarbon generation mechanism of organic-rich shale remain unclear. This study used organic geochemistry, gold-tube pyrolysis experiments, and basin simulations to evaluate the potential, characteristics, and process of generating hydrocarbon in organic-rich shale from the Shanxi Formation. The results showed that the total organic carbon (“TOC”) content of the downhole and outcrop samples (shale, carbonaceous shale and coal) is high. In addition, the organic matter (“OM”) type is mainly type III kerogen. Further, the Ro distribution of downhole samples ranged from 2.28% to 3.12% (2.62% on average), indicating that OM is in an overmature stage (generating a dry gas stage). Based on the analysis of the characteristics of gold-tube pyrolysis products, the hydrocarbon generation process can be divided into four stages. At a heating rate of 2 °C/h, the highest yields of C6+, C2-5 and C1 were 75.34 mg/g TOC, 16.20 mg/g TOC, and 138.74 mg/g TOC. These results indicate that the Shanxi Formation shale has good gas generation potential and belongs to a typical gas source rock. Under the actual geological conditions, the Shanxi Formation organic-rich shale of wells D5 and D3 almost stopped producing natural gas at approximately 104 MPa. The OM transformation ratio (“TR”) of the Shanxi Formation shale of wells D5 and D3 reached 85.58% and 83.97%, respectively. The gaseous hydrocarbon yields were 66.83 mg HC/g TOC and 32.35 mg HC/g TOC, respectively. This study's results revealed that marine-continental transitional organic-rich shale has a strong gas-generating capacity. This capacity can provide an important gas source for shale gas enrichment, showing a high shale gas resource potential.

Insights into size-fractionated anammox granules presented with refractory organics from municipal wastewater-driven partial denitrification to improve the synergy of anammox and denitrification

The recently developed Partial Denitrification/Anammox (PD/A) is an emerging process for simultaneous ammonium and nitrate removal, while the remaining organics from PD may pose an adverse effect on the subsequent anammox process. In this study, a granule-based anammox UASB reactor was developed with receiving municipal wastewater driven PD effluent that contained a certain amount of refractory organic matter, the characterization of different size-fractionated granules on nitrogen removal and microbiological mechanisms were investigated. Anammox activity increased with granule size, while an oversize exceeding 2.5 mm would lead to activity reduction. Significant denitrification activity was detected, it exhibited a contrary relationship with anammox activity. Delightedly, the denitrification was observed to proceed with high nitrite accumulation, especially in smaller granules with nitrate-to-nitrite transformation ratio (NTR) above 84.4%. These results were confirmed by microbial analysis, anammox genus including Candidatus Kuenenia, Brocadia, and Jettenia were identified in all granules, their abundances increased with granule size, and the dominated Kuenenia preferred to grow in larger granule. Various kinds of denitrification bacteria were detected with the relative abundances increased with the decrease in granules size. Particularly, the Thauera that responsible for PD with high nitrite accumulation was revealed to grow in such system, its relative abundance in small-size granules (12.9%, <0.5 mm) was much higher than the large ones (<2.3%). Overall, this study improved our understanding of the synergy of anammox and denitrification bacteria between size-fractionated granules, it provides a guide for system optimization towards great stability by biomass segregation strategy, and sheds new light to develop an efficient anammox coupling with PD process in continuous-flow UASB reactor.

Trigger Properties of an Ejected-Plasma-Triggered SF Gas Gap for 10-kV Smart Distribution Network

Aimed at developing a rapid control and protection switch for a 10-kV smart distribution network, a gas switch triggered by ejected plasma was designed and tested. The switch met the requirements of fast and reliable triggering at an extremely low operating coefficient. The gas switch employed sulfur hexafluoride (SF6) as its insulating medium for miniaturization requirements and was triggered by capillary discharge excited by a pulse transformer for high potential isolation considerations. The influence of a capillary cavity structure and pulse transformer parameters on the switch trigger characteristics was investigated. The results showed that the plasma ejection was enhanced by increasing trigger energy, but was also saturated with a limited cross section of the magnetic core of the pulse transformer, which determined the maximum transferred trigger energy. Employing a long capillary, shrinking nozzle, and small transformer ratio promoted plasma ejection, resulting in an increase in the triggering reliability and lowering the trigger threshold voltage. A 4-mm capillary cavity with a shrinking nozzle driven by a 37/2 pulse transformer was used to trigger an 80-kV SF6 gas switch at a 4.7% operating coefficient, and 1200 times successive and successful triggering was performed, with the trigger delay ranging from 62.5 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$73~\mu \text{s}$ </tex-math></inline-formula> , which met the technical requirements of rapid control and protection for a 10-kV smart distribution network.

SWITCH-FILTER ON A RECTANGULAR WAVEGUIDE PARTIALLY FILLED BY DIELECTRIC

At article investigates a broadband switch for microwave technology, antenna-feeder paths of which are implemented on a rectangular waveguide partially filled by dielectric. Modern means of communication of the microwave range can operate for transmission through two independent antenna channels, each of which includes its own microwave transmitter. It is also provided the operation of one microwave transmitter for two antennas. The transmission of high-power signals requires the implementation devices based on rectangular waveguide partially filled by dielectric for such antenna-feeder paths. The active element is an open nonlinear structure included in a dielectric plate which located in a rectangular waveguide. The electrodynamic problem is solved by the method of eigenfunctions. In this article, the transfer coefficient T11 and plotted the graphs of the dependence of the electrical length of the waveguide segment with the open nonlinear structure on the value of the reactive conductivity of the inductive loop at fixed reactive conductivity of the open nonlinear structure is determine. The results of this article can be used in the development of broadband switches for mobile digital combined troposcatter-radio relay stations with space-diversity transmission, antenna-feeder paths of which are implemented on the rectangular waveguide partially filled by dielectric. The article developed a filter on waveguide tees partially filled by dielectric. A design based on an H-tee on a rectangular waveguide partially filled by dielectric is proposed. The equivalent circuit of the H-tee is based on the equivalent circuit in the longitudinal slot in the narrow wall of the waveguide. Such a gap interrupts the lines of the transverse surface current of the main quasi-H10 wave of a rectangular waveguide partially filled by dielectric. Numerical results are obtained for transformation ratios.

What is the speed limit of martensitic transformations?

ABSTRACT Structural martensitic transformations enable various applications, which range from high stroke actuation and sensing to energy efficient magnetocaloric refrigeration and thermomagnetic energy harvesting. All these emerging applications benefit from a fast transformation, but up to now their speed limit has not been explored. Here, we demonstrate that a thermoelastic martensite to austenite transformation can be completed within 10 ns. We heat epitaxial Ni-Mn-Ga films with a nanosecond laser pulse and use synchrotron diffraction to probe the influence of initial temperature and overheating on transformation rate and ratio. We demonstrate that an increase in thermal energy drives this transformation faster. Though the observed speed limit of 2.5 × 1027 (Js)1 per unit cell leaves plenty of room for further acceleration of applications, our analysis reveals that the practical limit will be the energy required for switching. Thus, martensitic transformations obey similar speed limits as in microelectronics, as expressed by the Margolus – Levitin theorem.

Rapid enrichment of anammox bacteria and transformation to partial denitrification/anammox with nitrification/denitrification sludge

The stable nitrite (NO2−-N) generation and rapid startup of anammox-based process are the main bottlenecks hindering its application in mainstream municipal wastewater treatment. In this study, a Partial-Denitrification (PD) system reducing nitrate (NO3−-N) to NO2−-N was rapidly developed within 40 days, using the nitrification/denitrification sludge from wastewater treatment plant. The NO3−-N to NO2−-N transformation ratios achieved 80.6 %. Significantly, a fast self-enrichment of anammox bacteria in this system was subsequently obtained, resulting in the successful transformation to an efficient PD/Anammox (PD/A) process after 79-day operation. The total nitrogen removal efficiency increased from 12.4 % to 90.0 % with influent ammonia and nitrate of 45.9 mg N/L and 62.2 mg N/L, corresponding to the anammox activity significantly increasing to 6.0 mgNH4+-N/g VSS/h without seeding anammox sludge. Abundance of anammox increased from 6.7 × 108 to 2.0 × 1011 copies/g dry sludge. High-throughput sequencing results showed that Candidatus Brocadia was the only known anammox genus and accounted for 1.08 % during the PD/A stage. Functional bacteria for PD, assumed to be the Thauera, was enriched from 1.99 % to 60.06 % but decreased to 32.49 % during the improvement of anammox activity. It demonstrated that the PD system with stable NO2−-N accumulation enabled a rapid self-enrichment of anammox bacteria and sufficient nitrogen removal with ordinary nitrification/denitrification sludge. This provides new insights into the scaling application of anammox by integrating PD with shortened startup periods and improved TN removal efficiency.

The effect of Pliocene volcanic intrusive rocks and thermogenic gas generation from the Miocene Salif Formation in the offshore Tihamah Basin, Yemeni Red Sea

Organic geochemical and basin modeling methods were used to investigate the potential of thermogenic gas generation from the source rock of the Miocene Salif Formation. The analyzed Salif shales were collected close to the intrusive volcanic rocks intersected by the Kathib-01 well in the offshore Tihamah Basin, Yemeni Red Sea. Generally, the analyzed Salif shale samples have total organic matter (TOC) values up to 3.4 wt %, overall, indicating organic matter richness capable of generating hydrocarbons. The analyzed Salif shale samples have low hydrogen index (HI) values of <200 mg HC/g TOC, indicating mainly Types IV and III kerogen. These results are in contrast with the presence of dominated hydrogen-rich Type-II kerogen in the Salif shales from the close location of the exploration wells e.g., Al-Auch-01, Al-Meethag −01 and Al-Meethag −02. Therefore, the drastic alteration of the original organic matter of Type II and decreasing HI values, as a result of conversion of kerogen to HCs in the studied well, is due to the high thermal maturation as indicated from thermal maturity indicators. The Salif shale samples in the studied well have reached the main stage of the gas generation window, implying that the Salif Formation has substantial thermogenic gas generation. The increase in thermal maturity in the studied well was caused by the presence of the intrusive volcanic rocks that extruded during the Pliocene age as a result of the regional uplift of rift shoulders.Based on the burial/thermal/generation model of the Kathib-01well, the conversion of kerogen to oil and the subsequent cracking of the retained oil into thermogenic gas has been simulated. During the early to late Pliocene age (5–2 Ma), 10 to about 60% of kerogen was converted to oil, matching the peak mature to late mature of oil window (0.75–1.35 %Ro). Moreover, oil was cracked into thermogenic gas during end of the late Pliocene until the present day (2-0 Ma), indicating the beginning of the gas generation window (>1.35% Ro) with a transformation ratio (TR) above 99%. The prediction of a significant charge of thermogenic gas generation from the Salif Formation in the studied Kathib-01 well is due to the presence of the volcanic intrusive rocks extruded during the late Pliocene to present day time.