Academic literature on the topic 'FA. Co-operation'

A series of chloro-functionalized ionic liquids (CFILs) with chlorine groups (–Cl) on cations and chloride anions (Cl-) were synthesized and used as the promotion reagents for the selective conversion of cellulose into levulinic acid (LA) with the co-product of formic acid (FA). The co-operation between cations and anions of CFILs was investigated intensively through the variation of the structure of cations and the addition of salts with different anions. 3-(3-chloropropyl)-1-methyl-imidazolium chloride (IL-3) was the most appropriate additive, achieving up to 4.2%, 52.6%, and 58.7% of glucose, LA, and FA yields at 83.5% of cellulose conversion, respectively.

s-ACE (the somatic form of angiotensin-converting enzyme) consists of two homologous domains (N- and C-domains), each bearing a catalytic site. Negative co-operativity between the two domains has been demonstrated for cow and pig ACEs. However, for the human enzyme there are conflicting reports in the literature: some suggest possible negative co-operativity between the domains, whereas others indicate independent functions of the domains within s-ACE. We demonstrate here that a 1:1 stoichiometry for the binding of the common ACE inhibitors, captopril and lisinopril, to human s-ACE is enough to abolish enzymatic activity towards FA {N-[3-(2-furyl)acryloyl]}-Phe-GlyGly, Cbz (benzyloxycarbonyl)-Phe-His-Leu or Hip (N-benzoylglycyl)-His-Leu. The kinetic parameters for the hydrolysis of seven tripeptide substrates by human s-ACE appeared to represent average values for parameters obtained for the individual N- and C-domains. Kinetic analysis of the simultaneous hydrolysis of two substrates, Hip-His-Leu (S1) and Cbz-Phe-His-Leu (S2), with a common product (His-Leu) by s-ACE at different values for the ratio of the initial concentrations of these substrates (i.e. σ=[S2]0/[S1]0) demonstrated competition of these substrates for binding to the s-ACE molecule, i.e. binding of a substrate at one active site makes the other site unavailable for either the same or a different substrate. Thus the two domains within human s-ACE exhibit strong negative co-operativity upon binding of common inhibitors and in the hydrolysis reactions of tripeptide substrates.

Tumor hypoxia is considered as an important factor for tumor metastasis and disease recurrence. Evofosfamide (TH-302) is a hypoxic prodrug, which can selectively target the hypoxic area of solid tumors, and has the potential to improve the efficacy of the commercial anticancer drug afatinib (AFT). However, free hydrophobic AFT and hydrophilic TH-302 still have several unequivocal deficiencies, such as unsatisfactory tumor inhibition rate, serious side effects and being easy to induce multidrug resistance. Moreover, the operation process of co-administration is too complicated. Therefore, this paper discussed the synergistic effects of AFT/TH-302 and developed a kind of co-loaded targeted mesoporous silica nanoparticles (MSNs) for the treatment of nasopharyngeal carcinoma (NPC). The calculated proportion of AFT and TH-302 were encapsulated by folic acid (FA) modified MSNs (FA-MSNs). In vitro experiments showed that free AFT and TH-302 had synergistic effect, while MSNs nanocarrier could significantly reduce the half maximal inhibitory concentrations (IC50) of AFT and TH-302. AFT and TH-302 show significant synergistic on NPC cells, the application of MSN carrier platform including fixed proportion of AFT and TH-302 improves the synergistic effect and provides a new idea for the treatment of NPC.

Introduction. The wide-scale use of catalytic converters and particulate filters in automobile engines has aggravated the problem of their ignition and updated the research and methodological framework for the examination of causes of fire emergency modes (FEMs) of operation of fuel catalytic units (FCUs). The relationship between the FEMs of the FCU operation and failures of the fuel equipment, wear of the cylinder-piston group of engines and deviations in fuel compositions was confirmed. The goal was to develop a diagnostic method for fire hazardous modes of operation of FCUs of vehicles.Methodology. A model of oxidative catalysis underway in the FCU has been proven rational. The model is used to calculate the thermo-catalytic efficiency and heat generation in the active layer of the γ-Al2O3 platinum catalyst depending on the temperature of exhaust gases (EG), concentrations of CO, CH and soot. It has been found out that catalysis can theoretically develop in four limit domains: internal kinetic domain, internal diffusion domain, external diffusion domain, and external kinetic domain.Results and discussion. Experimental and computational studies have shown the probability of emergence of breakdown vehicles with a multiple excess of soot emissions and thermal stresses. A 10‑fold increase in CO, CH and soot in EG rises the thermal performance of the catalytic reaction from 17,282 to 491,907 kJ/h, creating a fire hazard in a KamAZ engine. To identify a FEM, the diagnostic method based on the «free acceleration» (FA) mode according to GOST 33997–2016 is proposed. The procedure is supplemented with maximum revolutions and restrictions (0.5 s) of the FA mode time. The latter is necessary for the guaranteed operation of the engine in the «full load mode». The method was applied in the course of the fire engineering studies on a Ford Mondeo car having a TDCi (Common Rail System) diesel engine and a catalytic particulate filter. Laboratory examination and analytical studies have found that the main reason for the operation of FCU in emergency (due to environmental and fire hazards) modes is the corrosion of precision parts of the fuel equipment accumulated during its long-term operation. Progressive corrosion is caused by excessive sulfur and moisture content in fuel and oil.Conclusions. It’s been proven that the emergency heating of a catalytic converter causes a sharp rise in the car combustion risk. The authors have proposed an original method for the diagnostics of fire-hazardous modes of operation of catalytic converters based on procedures set in GOST 33997–2016 (ТР ТС 018/2011).

Patient with malignant Gestational Trophoblastic Neoplasm (GTN) was treated by mean of MTX-FA, MAC, EMA-CO and EMA-EP. Changes in serum human chorionic gonadotropine (beta hCG) levels and changes in ultrasonographic findings were checked weekly. Finally transabdominal hysterectomy with ovaries conservation was done and polychemotherapy administrated after the operation until three consecutive serum chorionic gonadotropine values were negative. This is a case report of Invasive mole in 32 years old patient without possibility to preserve reproductive health. GTN developed two months after spontaneous abortion in 13th week gestation. No changes in uterine structure were found during the first ultrasonographic examination. Three months after abortion and one month after GTN confirmed, massive destruction of lateral uterine wall was detected during transvaginal Doppler ultrasound examination. Resistance index of 0,366 was significantly lower than normal, with hypervascularisation in affected tissue. Serum beta hCG confirmed poor effect of polychemotherapy treatment and decision for operative treatment was made. Hystological findings after the operation confirmed malignant GTN- invasive mole. Specific changes in ultrasonographic picture could have an impact in therapy making decision and could not be refereed without the most relevant parameter such is serum human chorionic gonadotropine.

In order to break through the dual impacts of lower birth rates and COVID-19, a majority of higher education institutions have commenced in providing a series of diversified Massive Open Online Courses (MOOCs) to effectively reduce these huge dual impacts. This research employed the Social Learning Theory (SLT) of educational doctrine for theoretical uses and the Factor Analysis (FA) approach of quantitative analysis and Trigonometrical Entropy Method (TEM) method of qualitative analysis for statistically purposes. These concepts were employed to explore the most critical social-media connection of global literacy abilities in MOOC. After a succession of assessed measurements, there are two most valuable findings. First, higher education institutions have to simultaneously and efficiently institute the Course Complete Rate of Course Assessment (CCR-CA), User Completely Unrestricted Operation of Course Operation (UCUO-CO) and Course Professionalization Technology Function of Course Function (CPTF-CF) into the course’s design. Specifically, higher education institutions need to establish MOOCs features in Course Evaluation Technology Function (CETF), Course Professionalization Technology Function (CPTF) and Aggregation Technology Function (ATF) of MOOCs features into the current MOOCs. This is done in order to effectively promote the Individual Social Feature (ISF) of “social-media connection of global literacy abilities” for overcoming these serious dual impacts. In addition, higher education institutions have to also construct the social-media connection of global literacy abilities evaluation model for appraising Individual Social Feature (ISF) of each MOOCs participant. Second finding, higher education institutions should develop Convenience of Course Operation (C-CP), Feedback Technology Function of Basic Function (FTF-BF) and Connectionization of Course Operation (C-CO) of higher education strategies of developed sustainability into the course’s structure. Further, they should also build Connectionization (CZ) of MOOCs features into the current MOOCs in order to efficiently foster Application Programming Interface (API) of social-media connection of global literacy abilities for conquering these serious dual impacts as well.

2,5-furandicarboxylic acid (2,5-FDCA) is a biomass derivate of high importance that is used as a building block in the synthesis of green polymers such as poly(ethylene furandicarboxylate) (PEF). PEF is presumed to be an ideal substitute for the predominant polymer in industry, the poly(ethylene terephthalate) (PET). Current routes for 2,5-FDCA synthesis require 5-hydroxymethylfurfural (HMF) as a reactant, which generates undesirable co-products due to the complicated oxidation step. Therefore, direct CO2 carboxylation of furoic acid salts (FA, produced from furfural, derivate of inedible lignocellulosic biomass) to 2,5-FDCA is potentially a good alternative. Herein, we present the primary results obtained on the carboxylation reaction of potassium 2-furoate (K2F) to synthesize 2,5-FDCA, using heterogeneous catalysts. An experimental setup was firstly validated, and then several operation conditions were optimized, using heterogeneous catalysts instead of the semi-heterogeneous counterparts (molten salts). Ag/SiO2 catalyst showed interesting results regarding the K2F conversion and space–time yield of 2,5-FDCA.

Environmental contextDenitrifying anaerobic methane oxidation (DAMO) is a new process in wastewater treatment with the potential to provide cheap and sustainable development. To better apply this technology to the large scale, we studied the response mechanism of DAMO microorganisms to ammonia, the main form of nitrogen in the nitrogenous wastewater. The results can provide a theoretical basis for the stable and efficient operation of DAMO processes. AbstractThe dominant microorganisms in the denitrifying anaerobic methane oxidation (DAMO) process are primarily DAMO bacteria and DAMO archaea, which can simultaneously realise methane oxidation and denitrification. Ammonia is the primary form of nitrogen found in wastewater. This study focuses on a coexistence system that contains both DAMO bacteria and DAMO archaea (DAMO co-system). The short- and long-term effects of NH4+-N on the DAMO co-system were investigated at both the macro level (such as denitrification performance) and the micro level (such as microbial structure and community). Short-term experimental studies demonstrated that the safe concentration of ammonia for this system was 250mgNL−1. When the ammonia concentration was 500mgNL−1, the nitrogen removal efficiency was significantly inhibited. With an increase in concentration and an extension of time, the inhibitory effect of ammonia was enhanced. Long-term experimental studies showed that the nitrogen removal performance of DAMO was completely inhibited when the ammonia concentration reached 1000mgNL−1 and that ammonia had a toxic accumulation effect on the DAMO co-system. The results of the pH experimental study demonstrated that free ammonia (FA) was the limiting factor in the alkaline condition, while ionised NH4+ was the limiting factor in neutral and acidic conditions. Scanning electron microscopy (SEM) demonstrated that the microbes in the DAMO co-system shrank after short-term exposure and that the microorganisms shrank in the shape of polygons. High-throughput sequencing analysis demonstrated that the community structure of the DAMO co-system changed substantially, and the species diversity and abundance decreased distinctly after long-term inhibition. A genus analysis indicated that the reduction in Nitrospirae may be an internal reason for the decrease in the denitrification performance of the DAMO co-system.

Electrocatalytic carbon dioxide reduction reaction (CO2RR) technology can simultaneously minimize the CO2 concentration in the atmosphere and generate useful chemicals and fuels. Liquid formic acid (FA) produced from CO2RR is a chemical feedstock for industrial purposes as well as a potential hydrogen storage medium. The downstream separation of liquid FA from the CO2RR effluent increases the total costs in addition to the electrolysis and can also affect the environment adversely. Therefore, efficient, low-cost, and environmentally benign technologies for FA separation from the CO2RR are important for life cycle analysis and techno-economic analysis for this technology. Ion exchange has been proven as an advanced process for FA separation from aqueous solution. This method has attractive due to its high selectivity, low cost, ease of operation and recovery, availability to integrate with other systems, and environmentally benign nature. In this work, three anion exchange resins: Ambersep 900 hydroxide, Amberlite IRA-96 free base, and Amberlite IRA-910 chloride forms have been tested to separate FA from the aqueous solution under varying resin loading (10-60 mg/mL) and initial FA concentration (0.05-0.50 M). The effect of potassium bicarbonate, a commonly used catholyte in electrochemical CO2RR on equilibrium FA adsorption capacity has been investigated with resin loading of 10 and 60 mg/mL under similar initial FA concentrations. Kinetics and equilibrium studies data for the FA adsorption on three resins are interpreted using several kinetics and isotherm models. The kinetics data fits better with pseudo first order at high initial FA concentration and pseudo second order at low initial FA concentration. The results show that the Ambersep 900 hydroxide form with adsorption capacity of 430.8 mg of FA per g of resin is more efficient than the Amberlite IRA-96 free base form (369.9 mg/g) and Amberlite IRA-910 chloride form (291.2 mg/g) in the absence of potassium bicarbonate in the range of parameters studied. However, Amberlite IRA-96 (153.4 mg/g) and Amberlite IRA-910 (143.4 mg/g) can separate FA more efficiently from the potassium bicarbonate aqueous solution than the Ambersep 900 (94.1 mg/g). The experimental data for all resins can be well explained with the Freundlich isotherm model. In the presence of potassium bicarbonate, competitive adsorption of bicarbonate and formic acid reduces the FA adsorption capacity of resins. Experimental and modeling results will be discussed.

The development of an electrochemical catalyst system that converts carbon dioxide (CO2) to high-value chemicals, such as formic acid (FA) will simultaneously curb CO2 emissions to atmosphere and provide sustainable pathways to create a range of fuels at lower cost. Electrochemical conversion of CO2 to FA is a two-electron reduction process and can be carried out at ambient conditions, and the reduced product has been found wide-ranging applications in chemical industries for production of household products, and a safe liquid-phase chemical for hydrogen storage. Synergistic bimetallic electrocatalysts can improve the activity and selectivity over their monometallic counterparts by tuning the structure, morphology, and composition. At the University of Kentucky’s Institute for Decarbonization and Energy Advancement (UK IDEA), our enhanced bimetallic oxide carbon utilization (EBOCU) process uses an engineered catalyst that facilitates operating at relatively low applied potentials, and high product selectivity to produce FA. Using bimetallic tin-copper oxide containing 95 mol% of Sn and 5 mol% of Cu immobilized on mesoporous carbon xerogel and alkaline electrolyte, we observed that hydrogen evolution reaction is suppressed and the selectivity towards formate is enhanced for the cell potential from 3.6 V through 4.0 V. Notably, our electrochemical reactor is successful in converting CO2 to formate at the rate of 2 mM/h in 3 mL/min flow system. Maximum faradaic efficiency of 94% is achieved towards formate at 3.8 V, which remained above 80% even after 200 h of continuous operation.

The proposed VUT Art Campus is situated around the area of the streets Úvoz, Údolní, Tvrdého, Všetičkova and Jiříkovského. It lies in between two of the Brno’s most attractive recreational spots, Špilberk and Kraví hora. The project offers a creative solution of connecting two VUT’s faculties, the Faculty of Architecture and the Faculty of Fine Arts. An important part of the proposal is the gallery of the students’ works which also serves as a connecting element between the faculties. One of the main objectives is the creation of the Green Line originating at Špilberk and finishing at Kraví hora. As such, the campus works as a cultural point of interest on the way around the city. The whole concept aims to highlight the uniqueness of the faculties while stretching the importance of their interconnection and the need of a co-operation.

The 60 Hz, Frame 7F engine has been in commercial operation for more than two decades now with approximately 800 Frame 7 (F, FA, FA+ and FA+e models) machines existing in North America and a total of over 1100 F-class machines throughout the world. Of importance to operators/users and owners of this gas turbine engine is the ability to not only recondition the turbine “hot-end section” components, in order to support maintenance requirements, but also to reduce the life cycle costs of these components. Stage 1 nozzles are a cast doublet, manufactured from FSX-414 Co-based superalloy. There are 24 nozzles in an engine set. As a result of the extreme turbine inlet temperatures at the 1st stage nozzle, these components experience severe thermal fatigue cracking. On one particular OEM engine set inspected, over 600 cracks were identified on each nozzle after engine operation. As a consequence, the stage 1 nozzles when compared to the other components in the engine exhibits the worst degradation and is therefore a focus point of reconditioning for those in the industry. The technical objective is to describe the development of a repair scheme for the stage 1 nozzle that can successfully address and repair this level of severe cracking and oxidation, with 0% scrap/fallout for a heavy repair, after a normal duty cycle. Special processes have been established for these components repairs, including but not limited to removal of the damaged and oxidized trailing edges by machining, high frequency Gas Tungsten Arc Welding (GTAW) of new trailing edge coupons. This technical paper describes the repair process development and implementation of the different stages of the repair schemes and shows metallurgical and mechanical characteristics of the repaired regions of the component. As a result of successfully executing these special processes, although a heavy repair workscope was implemented; all the nozzles were successfully repaired without any scrap.

Worldwide pressures for reduction of power generation costs force the manufacturers of gas turbines to develop highly efficient units. Recent advances in the developments of high temperature materials coupled with advanced cooling techniques allow the developments of the new generation of advanced gas turbines with firing temperatures at 2300*F, which are being presently deployed in the marketplace. In order to establish a reference point regarding the durability of these machines, EPRI (Electric Power Research Institute) has launched a program to assess the durability of this new generation of advanced gas turbines. The first gas turbine to be observed is the General Electric MS 7001 F, located at the Potomac Electric Power Co. (PEPCO) Station H in Dickerson, Md. The Durability Surveillance Program shall be performed for 3 years during peaking operation (mostly summer and winter) beginning in May 1992 and continuing till 1995. Close observation of the gas turbine operation and maintenance, extensive monitoring of turbine operational parameters, detailed recording of performance and operational parameters and expanded inspection of the hot gas path hardware are the main activities in this Durability Surveillance program. Similar test programs are planned for the Westinghouse 501 F gas turbine and the GE MS 7001 FA gas turbine. The results of these tests shall be available to EPRI member utilities and other advanced gas turbine users.

Driven by global warming, a relentless march towards increased fuel efficiency has resulted in increased firing temperature for HA-class engines without an increase in baseload emissions. Moreover, emissions compliance for CO, NOx, and unburned hydrocarbons are desired over increased range in gas turbine load. In addition, exceptional gas turbine operational flexibility is desired to address potential intermittency due to the penetration of renewables in the electrical grid. Staged/sequential combustion is a state of the technology to provide operational flexibility and reduced emissions in power generation gas turbines. GE Power’s 7HA-class gas turbine combustion system combines GE’s proven DLN-2.6+ combustion technology, that has run reliably for over 1.3 million fired hours across more than eighty 9FA.03, 9F.05 & 7FA gas turbine engines, with an axially fuel staged system (AFS). Axially staging combustion to two zones allows for increased firing temperature at baseload (while maintaining the same NOx level) by operating the later/second stage hotter than the first/primary stage. During low load operation as the gas turbine firing temperature is reduced, percentage fuel split in the staged fuel system can either be reduced significantly or turned off and thereby keeping the overall combustion system into emissions compliance over a wider range of firing temperatures. This paper presents both the development testing of the staged combustion in the FA and HA class gas turbine combustion system rigs at GE Power’s Gas Turbine Technology Laboratory and the validation testing of staged combustion system for the 7HA.01 engine completed during Spring 2016 at GE Power’s engine test facility in Greenville, SC. The paper also discusses the significant simplification of operational principle and flexibility of startup, loading and baseload operation of the 7HA combustion system. Discussion of engine test results will show how axial fuel staging was utilized to demonstrate emissions compliance ( NOx (15% O2) < 25 ppm; CO < 9 ppm), operation from 14% load to 100% load with low combustion dynamics and also to enable wide wobbe capability, which is a normalized measure of fuel flexibility.

An approach to improving the thermal cycle efficiency of combustion turbine (CT) based power plants is to develop thermal cycles with interceding, reheat, recuperation and humidification. Until recently, this was viewed by combustion turbine manufacturers as cost prohibitive and involving new operating and maintenance challenges. Also, early attempts by some manufacturers to develop sophisticated thermal cycles resulted in the realization that significant funds, personnel, and time are required. This investment could not be justified, particularly considering the availability of efficient and economical combined cycle (CC) plants. Therefore, increased efficiency for both simple and CC power plants has been achieved by raising the firing temperature and pressure of the basic Brayton cycle. However, every increase in the CT firing temperature required progressively higher development cost and increased NOx control challenges, which has re-awakened interest in advanced cycles. The Department of Energy’s Federal Energy Technology Center (FETC), in cooperation with combustion turbine manufacturers, is working on an Advanced Turbine Systems Program. The program goal is to develop technologies to provide a significant increase in natural gas-fired CC power generation plant efficiency with thermal efficiency target values in excess of 60%. Materials published in the program show that participating large CT original equipment manufacturers (OEM), are relying heavily on an increase in the CT’s firing temperature to approximately 2600 F (1700 K), with associated advancement in materials and cooling techniques, to achieve the target efficiency. Also employed are some improvements in component efficiency and various methods of utilization of heat in the bottoming cycle. The development of the necessary sophisticated materials and cooling techniques requires very significant development costs and is based on long duration and expensive experimental investigations and field demonstrations. Increasing the bottoming cycle efficiency primarily depends on the practicality of engineering solutions and capital vs operating cost trade-offs, and not on technology advancements. The current Cascaded Humidified Advanced Turbine (CHAT) technology, which utilizes existing, commercially proven combustion turbine and industrial hardware integrated in sophisticated thermal cycles, offers an achievable, practical and cost-effective alternative to a current CC plant. Current CHAT plants require relatively minimal engineering developments associated primarily with a) modification of the power shaft CT’s compressor discharge and turbine inlet plenums — for interfacing the HP shaft and other thermal cycle components — a very important engineering task, but not comparable in complexity to the development associated with further increase of the CT inlet temperature; and b) engineering of an HP expander with an inlet temperature of 1600 F (1145 K), essentially integrating steam turbine and industrial expander technologies. As it was shown collectively in the previously published references, in addition to an efficiency equal to that for CC plants (based on the same CTs), CHAT plants have significantly lower (10–20%) specific capital costs and have important operating advantages (higher than CC efficiency at part-load operation, with excellent load following and dynamic benefits, including rapid start capability). Those features reduce both the CHAT plant cost of electricity and offer a method to improve improve the economics of power generation systems due to the operational flexibility added by a CHAT plant. One of the most effective ways to increase the CHAT plant efficiency is to increase the HP expander inlet temperature from the current level of 1600 F (1145 K), which represents the level of the combustion turbine technology of the late 1960’s – early 1970’s. EPRI and ESPC have identified that a CHAT plant, based on the current combustion turbine technology (with turbine inlet temperature (TIT) of 2550 F (1670 K)), could achieve the ATS Program target efficiency of 60% with an HP expander inlet temperature of approximately 2000 F (1365 K). HP expanders with this relatively low turbine inlet temperature, as shown later, will require cooling of only the first stage nozzles and stage blades, if the newest single crystal alloys are used. However, the increase of the HP expander inlet temperature will be complicated by the relatively-high inlet pressure. This presents a significant engineering challenge, particularly if one would like to preserve the excellent start-up characteristics and other dynamic benefits of the CHAT plant. EPRI and ESPC are co-sponsoring the development of a high pressure expander with a target inlet temperature of 2000 F (1365 K). It will be shown that this HP expander, when integrated with a power shaft based on W 501 FA modified for the CHAT application, results in a power plant that will achieve the ATS Program target efficiency of 60%. This paper presents a) current CHAT plant’s performance and cost characteristics, b) findings of the project for the development of the HP expander with target temperature of 2000 F (1365 K), and c) a comparison of the advanced CHAT concept’s performance and development costs to those of the ATS program. This paper also shows how, in the future, the new ATS technology can be incorporated into even more efficient, cost-effective and reliable CHAT power plants.