bluuebunny/crossref_metadata_2025 huggingface dataset:
Hijacking of the nucleolar protein fibrillarin by TGB1 is required for cell‐to‐cell movement of Barley stripe mosaic virus
Authors: Li Zhenggang , Zhang Yongliang , Jiang Zhihao , Jin Xuejiao , Zhang Kun , Wang Xianbing , Han Chenggui , Yu Jialin , Li Dawei
Published: September 2017

Barley stripe mosaic virus (BSMV) Triple Gene Block1 (TGB1) is a multifunctional movement protein with RNA‐binding, ATPase and helicase activities which mainly localizes to the plasmodesmata (PD) in infected cells. Here, we show that TGB1 localizes to the nucleus and the nucleolus, as well as the cytoplasm, and that TGB1 nuclear‐cytoplasmic trafficking is required for BSMV cell‐to‐cell movement. Prediction analyses and laser scanning confocal microscopy (LSCM) experiments verified that TGB1 possesses a nucleolar localization signal (NoLS) (amino acids 95–104) and a nuclear localization signal (NLS) (amino acids 227–238). NoLS mutations reduced BSMV cell‐to‐cell movement significantly, whereas NLS mutations almost completely abolished movement. Furthermore, neither the NoLS nor NLS mutant viruses could infect Nicotiana benthamiana systemically, although the NoLS mutant virus was able to establish systemic infections of barley. Protein interaction experiments demonstrated that TGB1 interacts directly with the glycine–arginine‐rich (GAR) domain of the nucleolar protein fibrillarin (Fib2). Moreover, in BSMV‐infected cells, Fib2 accumulation increased by about 60%–70% and co‐localized with TGB1 in the plasmodesmata. In addition, BSMV cell‐to‐cell movement in fib2 knockdown transgenic plants was reduced to less than one‐third of that of non‐transgenic plants. Fib2 also co‐localized with both TGB1 and BSMV RNA, which are the main components of the ribonucleoprotein (RNP) movement complex. Collectively, these results show that TGB1–Fib2 interactions play a direct role in cell‐to‐cell movement, and we propose that Fib2 is hijacked by BSMV TGB1 to form a BSMV RNP which functions in cell‐to‐cell movement.
Microbial epidemiology of candidaemia in neonatal and paediatric intensive care units at the Children's Medical Center, Tehran
Authors: Charsizadeh Arezu , Mirhendi Hossein , Nikmanesh Bahram , Eshaghi Hamid , Makimura Koichi
Published: September 2017

Invasive candidiasis is a major cause of morbidity and mortality in children. However, limited data are available on the epidemiology of this infection in paediatric settings in Iran. The aim of this study was to determine the prevalence, microbial epidemiology, risk factors and clinical outcomes associated with candidaemia in intensive care units at the Children's Medical Center, Tehran, Iran. All blood and other normally sterile specimen cultures positive for Candida species were included. Isolates were identified by morphological and molecular methods. Unidentified/doubtful yeast isolates were subjected to ITS sequencing. A total of 156 episodes of invasive candidiasis, with an overall incidence of 15.2 per 1000 ICU admissions, was recorded. Risk factors included presence of central venous lines (89.1%), mechanical ventilation (55.8%) and parenteral nutrition (51.3%). Candida albicans (57.1%) and Candida parapsilosis (24.4%) were the most commonly isolated species. Candida orthopsilosis, Candida glabrata, Candida dubliniensis, Candida lusitaniae, Candida kefyr and Candida intermedia accounted for about 11% of the cases. The overall mortality rate was 42.5%. Non‐albicans Candida species accounted for nearly half of the cases of paediatric candidaemia. This is the first prospective study of candidaemia in paediatric settings in Iran and serves to inform necessary interventions for the prevention of candidaemia.
In vitro efficacy of disinfectants utilised for skin decolonisation and environmental decontamination during a hospital outbreak with Candida auris
Authors: Abdolrasouli Alireza , Armstrong‐James Darius , Ryan Lisa , Schelenz Silke
Published: September 2017

Candida auris has caused nosocomial infections and transmissions within hospital settings. As little is known about the efficacy of skin and environmental decontamination products to kill C. auris, this study investigated the in vitro activity of chlorine, chlorhexidine, iodine povidone and vaporised hydrogen peroxide products against C. auris. H2O2 vapour showed 96.6%‐100% effective killing of C. auris. All isolates were inhibited by chlorhexidine gluconate concentrations at 0.125%‐1.5% and for iodinated povidone at 0.07%‐1.25%. Other species of Candida were also killed at 1000 ppm chlorine except C. parapsilosis which failed to be killed at 3 minutes contact time. We conclude that chlorhexidine gluconate, iodinated povidone, chlorine and H2O2 vapour demonstrate effective killing activity against C. auris at concentrations used in clinical practice.
Early post‐natal development of the mandibular permanent first molar in infants with unilateral complete cleft lip and palate
Authors: Hermann N. V. , Darvann T. A. , Kreiborg S.
Published: September 2017

Structured Abstract

Objectives

Studies have shown that the mandibular permanent first molar (M1inf) in young children with isolated cleft palate is characterized by delay in maturation and has reduced crown width. Consequently, it is of interest to investigate the early maturation and width of the follicle and crown of M1inf in children with combined cleft lip and palate.

Design

Retrospective, longitudinal study. Cephalometric X‐rays of 47 consecutive Danish children with UCCLP (37 males; 10 females) and 44 with unilateral incomplete cleft lip (UICL) (29 males; 15 females) examined at 2 and 22 months of age. UICL served as control group. Maturation (according to Haavikko), width of follicle (FW) and crown (CW) of M1inf were assessed.

Results

The maturation of the first mandibular molar was delayed in both genders at 2 and 22 months of age. FW and CW were smaller in children with UCCLP at both 2 and 22 months of age. There was a positive correlation between maturation and FW.

Conclusions

Maturation of the first mandibular molar is delayed in both genders, and FW and CW were reduced in UCCLP compared to controls. Maturation was correlated with FW.
Implications of the population effect in the selection of soybean progeny
Authors: de Cássia Pereira Francielly , Bruzi Adriano Teodoro , de Matos José Wilacildo , Rezende Breno Alvarenga , Prado Luis Claudio , Nunes José Airton Rodrigues
Published: September 2017

The goal of this study was to verify the influence of the population effect in the estimates of genetic and phenotypic components and to identify the best soybean progeny or lines in a commercial soybean breeding programme. We evaluated 292 populations for grain yield and absolute maturity during three agricultural years. To quantify the efficiency of the inclusion of the population's effect in the model, we estimated genetic gain with the selection, the Spearman's correlation, the coincidence index, the realized gain and correlated response of selected genotypes with and without the effect of the population. It was found that the variance components, heritability and coefficient of experimental variation were better estimated when the effect of the population was included, providing greater gain with selection for grain yield and absolute maturity. Coincidence and ranking among the selected progeny with and without the effect of the population are of greater magnitude in more advanced inbreeding generations and at higher percentage of selected progeny. The use of the population effect has greater importance in earlier generations of inbreeding.
Short‐cut diagnostic tool in cystinosis: Bone marrow aspiration
Authors: Sürmeli Döven Serra , Delibaş Ali , Kayacan Uğur Raşit , Ünal Selma
Published: September 2017

Background

Cystinosis is a rare metabolic genetic disorder caused by a mutation in cystinosin lysosomal cystine transporter (CTNS). The diagnosis of nephropathic cystinosis (NC) is made by observing corneal cystine crystals and/or measuring the cystine content of leukocytes. CTNS mutation analysis confirms the diagnosis of cystinosis, but leukocyte cystine measurement and CTNS analysis have not been widely available, and cystine crystals in the cornea may not be apparent in the first months of life. Cystine crystal deposition can be seen in the bone marrow earlier than corneal deposition, in patients with NC.

Methods

Ten patients with cystinosis diagnosis were enrolled in the study. Medical records were reviewed retrospectively to collect demographic and clinical data such as age at diagnosis, disease presentation, parental consanguinity, family history, corneal cystine deposition, leukocyte cystine level, bone marrow cystine deposition, presence of renal failure, follow‐up time and prognosis.

Results

Cystine crystals were seen in all of the patients’ fresh bone marrow aspiration samples. Eight patients had corneal cystine deposition. Leukocyte cystine measurement could have been performed in four patients who had come from another center. Complications such as pulmonary hypertension and idiopathic intracranial hypertension (IIH) were observed in two patients.

Conclusions

Bone marrow aspiration might be an easy and short‐cut diagnostic tool for NC especially when it is not possible to measure fibroblast cystine content. Additionally some rare complications such as pulmonary hypertension and IIH can be encountered during the course of NC.
Spot blotch disease of wheat: the current status of research on genetics and breeding
Authors: Gupta P. K. , Chand R. , Vasistha N. K. , Pandey S. P. , Kumar U. , Mishra V. K. , Joshi A. K.
Published: September 2017

The spot blotch disease of wheat is caused by Bipolaris sorokiniana, which is an anamorph (teleomorph Cochliobolus sativus). The disease mainly occurs in warm, humid wheat‐growing regions, and the Eastern Gangetic Plains (EGP) of South Asia is a hotspot. Significant progress has been made in recent years in characterizing the host–pathogen interaction. The study of the pathogen's life cycle and diversity have been an active area of research. A number of resistance sources have also been identified, characterized and used for breeding. Although immunity has not been observed in any genotype, cultivars displaying a relatively high level of resistance have been developed and made available to farmers. Further progress will require regular use of marker‐assisted breeding, genomic selection, gene editing and transgenic interventions. This review summarizes the current state of knowledge about genetic and breeding efforts on the wheat–B. sorokiniana pathosystem and discusses ways in which emerging tools can be used for future research to understand the mechanism involved in infection and for developing cultivars exhibiting a high level of resistance.
A new allele, HLA‐DQA1*02:01:02
Authors: Galluccio T. , Guagnano A. , Stanglino G. , Vicenza T. , Andreani M.
Published: September 2017

The new allele, HLA‐DQA1*02:01:02 differs from DQA1*02:01:01:01 by C to T substitution in exon 2.
Efficient ASK‐assisted system for expression and purification of plant F‐box proteins
Authors: Li Haiou , Yao Ruifeng , Ma Sui , Hu Shuai , Li Suhua , Wang Yupei , Yan Chun , Xie Daoxin , Yan Jianbin
Published: September 2017

Ubiquitin‐mediated protein degradation plays an essential role in plant growth and development as well as responses to environmental and endogenous signals. F‐box protein is one of the key components of the SCF (SKP1‐CUL1‐F‐box protein) E3 ubiquitin ligase complex, which recruit specific substrate proteins for subsequent ubiquitination and 26S proteasome‐mediated degradation to regulate developmental processes and signaling networks. However, it is not easy to obtain purified F‐box proteins with high activity due to their unstable protein structures. Here, we found that Arabidopsis SKP‐like proteins (ASKs) can significantly improve soluble expression of F‐box proteins and maintain their bioactivity. We established an efficient ASK‐assisted method to express and purify plant F‐box proteins. The method meets a broad range of criteria required for the biochemical analysis or protein crystallization of plant F‐box proteins.
Effectiveness of predonation health and travel screening in reducing the risk of transfusion‐transmitted infections
Authors: Berg R. K. , Erikstrup C.
Published: September 2017

Early in the history of transfusion it became evident that blood can transmit infectious diseases from the donor to the recipient. Predonation screening is performed by a Donor Health Questionnaire (DHQ). The DHQ complements the blood screening programme, when it fails to detect transfusion‐transmitted infections (TTIs), or when TTIs are not covered by the blood screening programme. The DHQ is dependent on the donor understanding the items presented in the DHQ and discloses accurate information. DHQ has relatively high rates of non‐compliance. It has been suggested that donors do their own risk assessment when filling in the questionnaire. Reducing the deferral periods to some items in the DHQ has increased compliance without resulting in increased risk of TTIs. The advantage of the DHQ is the fact that it is adaptable, and can be easily expanded quickly with new emerging TTIs, however unfortunately, the questions in the DHQ are often introduced based on expert opinions rather than evidence‐based risk assessment. This may lead to unfeasible criteria with high rates of deferrals with consequently high costs for the blood centers or it might even pose a threat to maintain a sufficient blood supply. With the advances in the blood screening programme reducing the window period for serious TTIs, we here suggest that time is up to take a critical look at the DHQ, to evaluate the efficiency if the individual items, and to develop a DHQ that fits the current pressure of infections.
Weeds for weed control: Asteraceae essential oils as natural herbicides
Authors: Benvenuti S , Cioni P L , Flamini G , Pardossi A
Published: September 2017

The aim of this study was to test the botanical family of Asteraceae as a source of natural herbicides. Twenty Asteraceae species were collected during flowering time and evaluated in terms of the yield and quality of essential oils (germination inhibition and growth of weeds). Half the species showed a sufficient yield of essential oil (from about 0.1% to 1.43%) when testing these phytochemicals in vitro as germination inhibitors of two typical weeds, Amaranthus retroflexus and Setaria viridis. Despite the higher tolerance of S. viridis, the concentration of 100 μg L−1 of essential oils of the two Artemisia species and Xanthium strumarium could totally inhibit germination. In addition, at 10 μg L −1, the same essential oils showed full inhibition of A. retroflexus seeds. A comparison of their effectiveness at suboptimal doses led to a further selection of the most promising sources of essential oils. After their chemical characterisation, the essential oils were tested as post‐emergence herbicides on seedlings of the above‐cited weeds. After spraying the weeds at different concentrations (10, 100 and 1000 mg L−1) during two different phenological stages of weed seedlings (cotyledons and the third true leaf), the essential oils of Artemisia annua and X. strumarium showed the best performance. The essential oils of X. strumarium were then tested again on both weeds to monitor the dynamics of plant injury. A reduction in plant fresh weight (about 20%–30% after 10 days) and chlorophyll content (destroyed, after the same amount of time) was found, thus confirming the total and rapid effectiveness of these essential oils. In summary, A. annua and X. strumarium have elicited considerable agronomic interest and appear to be suitable as a source of essential oils to act as natural herbicides.
Orbit Response Recognition During Touchdowns by Instantaneous Frequency in Active Magnetic Bearings
Authors: Lyu Mindong , Liu Tao , Wang Zixi , Yan Shaoze , Jia Xiaohong , Wang Yuming
Published: September 2017

During touchdowns of active magnetic bearings (AMB), the violent collision between rotors and touchdown bearings (TDB) can cause damages to both parts. Orbit response recognition provides a way for the AMB controller to automatically switch the control algorithm to actively suppress the rotor–TDB vibration and promptly relevitate the rotor during touchdowns. A novel method based on Hilbert transform (HT) is proposed to recognize the orbit responses (pendulum vibration, combined rub and bouncing, and full rub) in touchdowns. In this method, the rotor suspension status is monitored by the AMB controller in real-time. When touchdown is detected, the rotor displacement signal during the sampling period is intercepted, and the instantaneous frequency (IF) is calculated by HT. Then, the local variance of IF during the sampling period is calculated, and it is compared with the threshold value. Combined rub and bouncing can be identified for it has the largest local variance. Finally, the mean value of IF during the sampling period is calculated and is compared with the other threshold value. Pendulum vibration can be identified for it has a lower and fixed mean value, while full rub has a larger value. The principle of the recognition method is demonstrated by the simulated results of a thermo-dynamic model. The results reveal that the method is feasible in recognizing the orbit responses and can be implemented in the AMB controller to help switch the control algorithms automatically in case of touchdowns.
A High Efficiency Coal-Fired Power Technology With Elevated and Conventional Turbine Layout
Authors: Feng Weizhong
Published: September 2017

The bottlenecks which in developing high-efficiency Ultra Super Critical (USC) coal power technology is analyzed under the background of great pressure of reducing CO2 emission on coal power industry. The development of 700°C Advanced Ultra Super Critical (A-USC) technology has been much slower than expected mainly due to the material limitations. Double reheat systems increase the efficiency at the cost of significant increases in expense and complexity. A cross compound unit with an elevated and conventional turbine layout greatly shorten the expensive high-temperature piping, significantly cutting the piping costs as well as reduce pressure drops and heat losses which increase the efficiency and the performance-price ratio of the power unit. Engineering study demonstrates the feasibility and advantages of this design. Existing 600 °C materials and equipment manufacturing capabilities were applied to the double reheat unit with the elevated and conventional turbine-generator layout, and adding other mature energy-saving technologies which had succeed in Shanghai Waigaoqiao No.3 Power plant to achieve a net efficiency of 49.8% (6849Btu/kWh, Lower Heating Value (LHV)). Combined with a series of innovative technologies that can improve the operating efficiency and keep the efficiency from decreasing, the annual net efficiency can achieve 48.8% (LHV). This efficiency level is high enough to meet the strict CO2 emission standard (636g/kWh) issued by Environmental Protection Agency (EPA) of the USA, showing significant demonstration of reducing CO2 emission.
Investigation of the Performance of a Diesel Engine Fueled by Biodiesel-Diesel Fuel Mixture With Addition of Nanoparticles
Authors: EL-Seesy Ahmed I. , Abdel-Rahman Ali K. , Hassan Hamdy , Ookawara Shinichi , Hawi Meshack
Published: September 2017

The current work presents the results of an experimental study that is conducted to investigate the effect of nanoparticles added to biodiesel-diesel fuel mixture. Nano-biodiesel-diesel mixture fuels were prepared by adding of multi-walled carbon nanotubes (MWCNTs). These nanoparticles were blended with biodiesel-diesel fuel in varying mass fractions using an ultrasonic stabilization. A diesel engine test rig was used to examine the effect of nanoparticles on engine performance and emission characteristics with a constant speed of 2500 rpm and different engine loads. The engine test results indicated that the biodiesel-diesel fuel blend slightly decreased the engine performance and increased its emission characteristics at all tested engine operating conditions. The use of nanoparticles was found to improve all engine performance parameters. Specifically, the maximum emission reduction was obtained at a dose level of 20 mg/l, where considerable emission reduction was observed; NOx by 14 %, CO by 30 %, and UHC by 34 %. Also, the best of both engine combustion characteristics and performance were reached at a dose level of 40–50 mg/l. Where the reduction in the brake specific fuel consumption was by 16 %, the increase in both the cylinder peak pressure Pmax, and maximum gross heat release rate dQg/dθmax. were 4 % and 1%, respectively. Finally, the recommended dose level to achieve a significant enhancement in all engine performance is 40 mg/l.
A Modified Master Cycle Off-Design Performance and Heat Rate Improvement Optimization
Authors: Fan Chenghao , Pei Dongsheng , He Xiang , Zhou Wentai , Wei Zengtao
Published: September 2017

Coal-fired power generation will continue to be the cornerstone of China’s energy sources in the coming decades and advanced ultra-supercritical technology is the future of coal-fired power generation. This paper selects double reheat cycle design for study and incorporates back pressure extraction steam turbine (BEST) into current cycle design, which used to drive boiler feed water pump and feed regenerative heaters. This design prevailed in US in 1960s and gradually was replaced by condensing turbine due to less efficiency benefits at subcritical steam condition. Reinvention of BEST design in current double reheat cycle is an evitable choice, because the efficiency advantage is improved at USC steam condition.

BEST configuration incorporated into current double reheat cycle and advanced cycle is developed to compare with other two conventional systems in this study. Thermodynamic simulation at design and off-design condition shows that BEST configuration has an obvious efficiency advantage at design load, but the advantage decreases at partial load. BEST expansion line and reheat pressure is integrated in cycle heat rate optimization. Genetic algorithm is chosen to implement the optimization and exergy analysis method is utilized to evaluate BEST expansion line optimization results. Finally, BEST design limitation and future work is practically concluded.
The Effects of the Air-Fuel Velocity Ratio on Turbulent Non-Premixed Bluff-Body Flames
Authors: Yang Tao , Zhang Jian
Published: September 2017

We reported the large-eddy simulations of a series of bluff-body flames varying air-fuel velocity ratio. The air-fuel ratio γ is defined by the ratio of external air velocity to central jet velocity, ranging from 0.05 to 0.50. The case of γ = 0.32 is exactly same the Sydney bluff-body HM1e flame. Firstly, the mathematical model and numerical method were validated in details as the simulation results are all in good agreement with measurements in HM1e flame. Then the interaction between turbulence and thermo-chemistry is revealed. As γ increases, external coflow trends to dominant the flame behavior. The stoichiometric mixture fraction shifts from the area between recirculation zone and central jet to the area between external flow and recirculation zone. Corresponding, the flame changes from jet-like, columnar to hat-like flames. The different level of local extinction and reignition is also observed. Local extinction and reignition occurs in jet-like and columnar flames. As γ increases, local extinction becomes easier and reignition becomes harder.
The Regeneration Effect of H2SO4 on V-W-TiO2 SCR Catalyst Deactivated by Alkali Metal
Authors: Du Yongbo , Wang Chang’an , Wei Xiaoyang , Lv Qiang , Zhao Yonggang , Cao Peiqing , Deng Lei , Che Defu
Published: September 2017

The sodium content in Zhundong coal is extremely high, which can accelerate the deactivation of the V-W-TiO2 selective catalytic reduction (SCR) catalysts. Sulfuric acid solution (H2SO4) washing has been verified as a famous method to regenerate the de-NOx performance for catalyst which has been poisoned by alkali metals. However, the performance of the regenerated catalyst in practice still needs to be investigated. In the present study, the resistance to sulfur dioxide (SO2) and the mechanical strength of the regenerated catalyst were experimentally studied as well as the continuous operation performances under several conditions. The results indicate that the de-NOx activity of H2SO4 regenerated catalyst is chemically stable below 300 °C and thermally stable below 450 °C. However, the catalytic activity of the regenerated catalyst could suffer a decline during operating under the SCR atmosphere at 450 °C, which is different from the fresh catalyst. Besides, the regenerated catalyst shows good SO2 resistance, whereas the mechanical strength is likely to be affected by the H2SO4 washing treatment.
Research on the Vibration Characteristic of Composite Rotor for Halfspeed Nuclear Power Turbine-Generator
Authors: Wang Xiu-jin
Published: September 2017

Shafting is one of the key units of large steam turbine generator set, its dynamic characteristics directly affect the technical level and operation effect of the new type large capacity Turbine-generator unit. The forces acting on the disc and the shaft are complex in operation. A composite rotor has various dynamic characters for a large capacity nuclear power Turbine-generator comparing with general rotor for its different structure. Numerical simulation was carried out to a composite rotor for a large capacity nuclear power T-G set, so as to analyze the influence of different length to diameter ratio on the vibration characteristics of the low pressure rotor and to study the effect of Interference Amount Between disc and shaft by using the three-dimensional finite element analysis in order to meet the requirements of the good vibration characteristics of the rotor. Firstly, the geometric model of the rotor is set up, and then the element model of the shafting is built, finally natural frequency of the rotor is calculated by using the mechanical module. Vibration characters such as the natural frequency and corresponding mode were obtained by analysis of vibration for the disc and shaft. The effect of the interference fit on critical speeds of the rotors are analyzed preliminarily. The results show that critical speeds of T-G rotor vary sensitively with magnitude of interference. (CSPE).
Modular Solar Systems for 24/7 Scalable, Flexible, Affordable Electricity
Authors: Anderson Bruce N.
Published: September 2017

A successful transition to a low carbon future requires that power be generated all of the time, 24/7, not just when the sun is shining. But few clean emissions power technologies can operate 24/7. Concentrated solar power (CSP) can because it can store thermal energy at 10–20% of the cost of batteries1 and can then burn fuel when its solar resource is exhausted. However, many see first generation CSP as too costly, complex, risky, and economical only at utility scale.

Alternatively, by mimicking the all-factory, standardized, modular approach of wind and PV, next generation CSP with low-cost dry thermal storage (e.g., firebrick, not molten salts), and using no water/steam (just hot air) may give CSP the potential to fulfill on its promise of baseload affordability.

This technical paper summarizes an Engineering and Cost Feasibility Study2 funded by the US Department of Energy as well as presents a new breakthrough power generation product based on the Brayton power tower system called 247Solar Plants™. Design, construction, and operation are all simplified with greatly reduced costs and increased deployment speeds.

Such modular CSP systems can be installed as single units or 100s of modules at utility scale. The microturbines used by the system stabilize grids by responding nearly instantly, similar to battery response time, to changing power demands and voltage fluctuations, while offering dispatchable, reliable electricity. The redundancy of multiple modules in a single project increases capacity factor, operational flexibility, and project reliability.

The DOE Study shows that such a system may be able to achieve the two key DOE targets included: 1) a capacity factor of at least 75%, of which >85% would be solar with <15% from fuels; and LCOE3s <9ȼ/kWh. Indeed, LCOEs under 6ȼ/kWh may be possible with further development and widespread deployment.
Numerical Simulation of High Temperature Solar Receiver and Thermal Receiver for Solar Micro Gas Turbine
Authors: Matsubara Koji , Isojima Sho , Nakakura Mitsuho , Yamada Yuji , Kawagoe Shota
Published: September 2017

Numerical simulation was made for high-temperature solar and thermal receivers of pressurized air for solar micro gas turbine system. The solar / biomass hybrid gas turbine was considered to generate 30kW to 100kW power. The gas turbine system was provided with the concentrated solar light from the dish reflector at the solar receiver and the combustion heat from the biomass synthesis gas at the thermal receiver. Numerical model was developed to the solar receiver and the thermal receiver to reveal their thermal potential.

The solar receiver was a close loop concentric annuli to receive highly condensed solar light of 1,000kW/m2. The inner cylinder was made of high-temperature resistance ceramic irradiated by the condensed light on the inner side. The liner was inserted between the inner cylinder and the outer shell. The pressurized air passes the many holes of the liner to impinge the outer surface of the irradiation wall. These impinging jets caused high heat transfer coefficient on the irradiation wall and alleviates the thermal distribution in the receiver aisle. The liner and the outer shell were made by the high temperature resistance INCONEL alloy.

The thermal receiver was also a close loop annuli. This uses the same part as the solar receiver and the biomass gas combustor combined to it. The combustor comprises of the liner and the center tube, installed to the inside of the ceramic cylinder. The biomass gas was provided to the gap between liner and the center tube, and the oxidant air to the outer side of the liner. The biomass gas was spouted from the many holes of the liner and mixed with the oxidant air. The resulted hot combustion gas impinged directly to the inner side of the ceramic cylinder. The impingement of the hot combustion gas thinned the thermal boundary layer and enhanced the heat transfer on the ceramic wall. The thermal receiver was designed to attain the preferable heat transfer performance by the inner impinging jet of the hot combustion gas as well as the outer impinging jet of the pressurized air.

Three dimensional numerical model was developed to the solar receiver and the thermal receiver considered in the present study using ANSYS FLUENT. Parameter study showed that the exit air from the solar receiver was heated above 1200K or higher presently, and was continued to search better condition and better configuration of the system to obtain higher temperature. The numerical simulation revealed that the distance from the jet nozzle (linear holes) and the heat transfer surface is critical to the thermal distribution. The concept of the new solar and thermal receivers was confirmed on their usefulness; the multiple impinging jet effectively enhanced the heat transfer on the ceramic wall of the solar receiver and the thermal receiver to reduce the thermal inhomogeneity near the heat transfer surface with pressure loss of order 800Pa.
Experimental Investigation of Performance Effect of Working Parameters on Bi-Evaporator Compression/Ejection Refrigeration System
Authors: Liu Huadong , Wei Xinli , Wang Zhenzhen , Geng Lihong , Li Chunhe
Published: September 2017

In this paper, a bi-evaporator compression/ejection refrigeration is experimental investigated to recycle the throttling loss in traditional vapor compression refrigeration cycle by using an ejector. The effects of working parameters on the system performance are mainly analyzed. The results are as follows: the ejector entrainment ratio decreases as the condenser and the high-temperature inlet water temperature increases, but rises with the increasing of low-temperature evaporator inlet water temperature; the system COP rises with the decreasing of inlet water temperature of condenser, and increases with the rise of inlet water temperature of high-temperature evaporator; the inlet water temperature of the condenser and the high-temperature has greater influences on the performance of BCERC system. The system COP increases about 0.25 when the condenser inlet water temperature decreases per 5°C; while the system COP rise about 0.114 as the high-temperature evaporator inlet water temperature increases per 5°C. The low-temperature evaporator inlet water temperature has little effects on the performance of the BCERC system. The results can be references for the design and operation of the BCERC system.
Analysis on High Temperature Corrosion Behaviors of Boiler Steels Under High-Chlorine Coal Ash
Authors: Liu Yacheng , Fan Weidong , Zhang Xiang , Wu Naixing
Published: September 2017

Chlorine is a harmful constituent in coal, contributing to severe high temperature corrosion on the super-heater and re-heater tubes in utility boiler firing high-chlorine coal (more than 0.3 wt.%). Characteristics of the corrosion contain not only the formed products on the metal surface, but also intergranular attack inner the alloy, resulting in great potential safety hazard and economic loss. The prevailing Cl-related mechanisms of high temperature corrosion involve active oxidation and fluxing, which mean both corrosive elements in the flue gas and deposits on the boiler metal surface can accelerate the corrosion. Cl2 as a catalyst in active oxidation can be released by sulfuration of alkali metal chlorides or reactivity by alkali metal chlorides with chromium/chromium oxide and iron/iron oxide or oxidation of HCl. However, the formation of low-melting eutectics (such as NaCl-Na2CrO4) in mechanism of fluxing can be an induction of severe corrosion because the rate of molten corrosion is much higher than chemical corrosion. Lab-scale experiments simulating the flue gas species, temperature gradient from hot flue gas (950 °C) to cold metal (610 °C), and deposit (four various Cl-containing coal ash) on the specimens were conducted in a tube furnace to investigate the corrosion of three common boiler steels (12Cr1MoVG, T91, TP347H). Furthermore, with the aid of the scanning electronic microscope associated with energy dispersive spectrometer (SEM-EDX) and X-ray diffraction instrument (XRD), the appearance and microstructure, the element contents, and composition of corrosion products on the specimens after corrosion have been analyzed. For high-chlorine coal, there existed white crystal on the surface of specimens (T91, TP347H) after corrosion test, and the XRD result showed NaCl, which can be explained by evaporation-condensation mechanism. However, no white crystal was detected for 12Cr1MoVG and it can be inferred that thick corrosion product layer with high thermal resistance was formed and 12Cr1MoVG suffered severe degradation. Through comparisons of alloy elements corroded in various oxidizers (Cl2, O2, and S), it can be seen that as the metal temperature increases, the negative value of Gibbs free energy for alloy elements corroded in Cl2 becomes higher, but the value is less corroded in O2 or S. Thus, alloy elements tend to be easier combined with Cl2, and Cl-induced corrosion is aggravated with the temperature increases. Similar results can be obtained by increased equilibrium vapor pressures of metal chlorides, evaporating easily and diffusing towards further to be oxidation. In comparison with high-chlorine coal, the corrosivity of low-chlorine coals on specimens were weak, especially for TP347H characterized with higher contents of Cr and Ni. Furthermore, the higher the ratio of Cl/2S or Cl/Na in the coal ash is, the more severe corrosion the specimens suffer.
Experimental Study of Mercury Removal and Electrolytic Regeneration by Ca(ClO)2 Solutions
Authors: Luo Qinlan , Jia Ruiya , Feng Bin , Zhou Qulan , Li Na
Published: September 2017

The trace element mercury (Hg0) released from fossil fuel combustion in thermal power plants is difficult to be collected by pollution control equipment as its high volatility, high volatility and low solubility. The removal of Hg0 is the most critical part of mercury removal technology. The existing technologies of mercury removal include activated carbon adsorption, fly ash adsorption, calcium-based adsorbent adsorption, and wet scrubbing method. While these existing technologies have some disadvantages, like high absorbent consumption, high absorption cost and existence of secondary pollution. Much attention has been devoted to the development of new mercury removal technology in recent years.

In this study, the Ca(ClO)2 solution was proposed for the absorption of elemental mercury as its strong oxidizing property and low expenditure. The chemical reaction mechanism, reaction kinetics and reaction thermodynamic in both absorption and regeneration processes were explored, which verified the feasibility of mercury removal and absorbent regeneration. Effects of solution concentration, absorption temperature and solution pH value on absorption performance of Ca(ClO)2 solution were investigated in micro bubbling reactor. The experimental results revealed that acid environment (pH = 1–5) and high solution concentration were beneficial to mercury removal. A high removal efficiency (over 90%) and a low outlet mercury concentration (below 0.01mg·m3) was obtained under optimal experimental parameters (with the pH value of 3, the solution concentration of 15 mmol·L−1 and the temperature of 25 °C). The performance of electrolytic regeneration in Ca(ClO)2 rich solutions were carried out, and the effect of electrolysis time on current efficiency and energy consumption in electrolytic regeneration processes were specifically studied. The regeneration results showed that the oxidation reaction of Cl− with a series of other oxidation reactions will occur at the anode, and the reduction reaction of Hg2+ will occur at the cathode. The results verified the feasibility of the electrolytic regeneration of Ca(ClO)2 rich solution using an ion-exchange membrane insulating the catholyte and the anolyte. The Ca(ClO)2 solution is a promising absorbent for elemental mercury which can accomplish the cyclic utilization of solution and the reuse of mercury.
Effect of Flow Direction of Heating Medium on Heat Transfer Performance of Single-Path Plate-Fin Evaporator
Authors: Shikichi Kazuaki , Ueno Takayuki , Asano Hitoshi
Published: September 2017

Effect of flow direction of heating medium on the heat transfer performance of upward evaporating refrigerant flows in a plate-fin heat exchanger was examined using HFC-134a as the refrigerant. The heat exchanger had a single refrigerant channel sandwiched by two water channels. Hot water flew upward or downward to form a parallel or counter flow heat exchange, respectively. To understand the heat flux distribution, temperature distributions on the outside wall of the water channel were visualized by an IR camera. As the results, it was shown that the difference in heat transfer rate between the parallel and counter flow was a little due to the large temperature difference in the heat exchange. The pressure loss of the refrigerant flow was larger for the parallel flow than the counter flow. It could be estimated from the wall temperature distribution that the increase in pressure loss might be caused by inhomogeneous phase distribution of the refrigerant flow.
Numerical Investigation on Two-Phase Flow Characteristic in the Separated Structure Shell-and-Tube Waste Heat Boiler
Authors: Shao Huaishuang , Wang Yungang , Ma Haidong , Zhao Qinxin
Published: September 2017

The shell-and-tube waste heat boiler is a common facility to recover and utilize the energy of flue gas in industries. To improve the ability and efficiency of the boiler, a steam dome is configured above the drum so as to arrange more heat exchange tubes. Simulation and analysis of vapor-liquid two-phase flow across tube bundles arranged in the drum are of vital importance to design and safety operation. Numerical simulation of boiling two-phase flow across tube bundles in the drum was carried out to analyze the shell side thermal-hydraulics. Commercial software ANSYS FLUENT 14.5 was adopted for modeling and computational calculations. The applied modeling approach was validated against experimental results with a good agreement. In order to analyze the vapor-liquid two-phase flow performance under various working conditions, the inlet velocity of downcomer tubes of 3m·s−1, 4m·s−1 as well 5m·s−1 for saturated water were simulated, respectively. The pressure field, flow characteristic, void fraction distribution and heat transfer characteristic were analyzed to have a good knowledge of the boiler operation. The following conclusions have been drawn through analyzing simulation results. (1)The total pressure drop on shell side increased with increasing the inlet velocity of downcomer tubes of saturated water. (2)The velocity of saturated water decreased after flowing into the drum less than z = 0.1m as the flow area increasing, and then increased rapidly as the volume of the mixture two-phase flow increasing. (3)The integral average void fraction of the drum decreased as the mass flow rate of inlet saturated water increasing. (4)The HTC (heat transfer coefficient) of the heat exchange tubes varied with the flow direction, which is related to the vapor-water void fraction. The conclusions obtained above can be used as a reference for the design of the separated structure shell-and-tube waste heat recovery boiler.
A Spot Check Information Management System of Wind Farm
Authors: Guo Sheng , Liu Yifan , He Jiahao , Yang Tao , He Guoqiang , Guo Shuxiang , Zhao Jian , Yang Haisheng
Published: September 2017

As most of wind farms are located at remote places with the large areas, it is difficult to manage wind farms and carry on the monitoring and diagnosis of wind turbines. Spot check is an effective way for the management of wind farm. The existing spot check information management systems are lack of effective management of data and further analysis functions, which makes the spot check data have not been fully used in judging the state of equipment. And the traditional spot check equipment has only simple functions including temperature and vibration detection. In order to solve the above problems, this paper develops a wind turbine spot check information management system. The spot check information management system manages the spot check routes, maintenance shifts, spot check staffs and other information. The spot check data can be uploaded to information management system via the wireless LAN. It can receive and deal with different kinds of signals such as vibration, temperature, noise and image signal. At the same time, it has the functions of vibration data analysis, trend analysis and prediction, fault diagnosis and so on, to judge the state of wind turbine. It can also export different kinds of spot check data report conveniently. According to field test, this spot check information management system can reasonably assign spot check tasks. And it can help to find the problem in time and reduce the maintenance cost.
The Technology Development of High Efficiency Steam Turbine
Authors: Yu Gang , Zhai Xuan , Hou Mingjun
Published: September 2017

Based on the rapid development of ultra-supercritical coal-fired units in China, by using material upshift and innovative structural design, such as double barrel cylinder, to improve the steam turbine high pressure and high temperature capability, by using the thermodynamic system optimization and high efficient flow technology to further improve the economy of steam turbine, DongFang has successfully developed a new generation of steam turbine, the parameters reach 35MPa / 615°C/ 630°C/630°C, heat consumption is lower than 6800 kJ/kWh, the generating efficiency of power plant exceeds 50%. This paper also introduces some technical development of future high-efficiency steam turbines at 650°C and 700°C.
Experimental Study of Spray Flame Characteristics in Hot-Diluted Oxidant Through Advanced Image Processing Technique
Authors: Li Yuan , Zhou Hao , Li Ning , Cen Kefa
Published: September 2017

This paper presents a study of ethanol jet spray flame characteristics in a hot-diluted oxidant with different co-flow oxygen concentrations and fuel/air mass flow rate ratios (MF/MA ratios) through advance image processing technique. An air-blast atomizer was located in a McKenna burner which was utilized to provide stable combustion surroundings and variable combustion atmosphere for ethanol jet spray. The co-flow oxygen concentrations were set to 5%, 10%, 15% and 21% (by volume) by adjusting the mass flow rates of CH4, O2 and N2. The MF/MA ratios were set to 0.245, 0.490, 0.735, and 0.980 by adjusting the fuel mass flow rate and the carrier air mass flow rate. A high-speed RGB CCD camera was employed to capture spray flame images continuously. Spray flame edge is detected using an auto-adaptive edge-detection algorithm which could detect the spray flame edge continuously and clearly. A flame zone is defined as the region surrounded by the detected flame edge to obtain flame parameters. Spray flame characteristics are described using the measured flame parameters, involving flame area, length, brightness, nonuniformity and temperature which are derived from the spray flame images. Spray flame area, length, brightness and nonuniformity are extracted through image processing technique directly. Moreover, two-dimensional (2D) temperature profiling of spray flame is obtained by coupling image processing technique with two-color pyrometry based on Planck’s radiation law. The effects of co-flow oxygen concentration and MF/MA ratio on spray flame characteristics are investigated in this work. The spray flame parameters are observed to be sensitive to both co-flow oxygen concentration and MF/MA ratio. The results show that the fuel mass flow rate (MF) has opposite effects on spray flame characteristics compared with the carrier air mass flow rate (MA) in hot-diluted oxidant. Spray flame area and length are shown to decrease for higher co-flow oxygen concentrations, while spray flame brightness, uniformity and temperature are observed to increase for higher co-flow oxygen concentrations, owing to the enhancement of the combustion rate. A higher MF/MA ratio leads to higher spray flame area, length, brightness, uniformity and temperature, due to the increase of the droplet residence time or droplet concentration in hot-diluted oxidant. In the same MF/MA ratio, spray flame area and length are found to be smaller at a higher fuel flow rate (or carrier air flow rate). However, spray flame brightness, uniformity and temperature are demonstrated to be enhanced at a higher fuel flow rate (or carrier air flow rate). (CSPE)