bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of Calcium Carbonate Build-Up in Condenser Tubes Restores Efficiency
Authors: Iervoline Larry (Irv) 
Published: September 2017

Water is essential to the power generation process, and for many power generation plants that rely on cooling water systems to condense steam, total hardness in source water is a problem. The high mineral content in many sources of cooling water results in hardened, calcified scale deposits forming on the walls of condenser tubes. These deposits form an insulation barrier inhibiting heat transfer. The scale also reduces the inner diameter of the tubes, restricting the flow of cooling water and further reducing heat transfer. As the heat transfer rate falls, performance of the condenser degrades, which can lead to decreasing megawatt output of the plant.
A power station in the United States sources hard lakewater for cooling. Like many plants utilizing hard water, the station relies on a water treatment program to control the formation of hard scale deposits. However, when the plant opened a closed cooling water exchanger (CCW) in its Unit 1, a layer of calcium carbonate was found on the tube walls throughout the bundle.
The CCW exchanger was shot with a variety of mechanical cleaners to thoroughly remove the scale and other deposits and debris from the tubes. Plant management suspected that the same problem might be occurring in the main condenser, and they understood that if scale was forming inside the condenser, the resulting loss in heat transfer rate would be a contributing factor in the decreased efficiency of the unit.
Since the plant was planning an eddy current test on 100% of the more than 12,000 stainless steel tubes in the main condenser, the tubes were required to be thoroughly cleaned. Upon opening the main condenser, technicians verified the presence of calcium carbonate fouling, confirming their suspicions. While not knowing the condition of the tubes underneath the deposit, plant engineers were concerned about the underlying tube condition. They were also looking for alternative cleaning methods to provide relief from environmental concerns often associated with chemical cleaning. To preserve tube integrity and assure thorough removal of deposits, the plant decided to clean the condenser tubes utilizing the same mechanical cleaning method as the CCW unit. The condenser tubes would be shot with a series of specialized mechanical tube cleaners, one designed to fracture the calcium carbonate and a second designed to remove the fractured scale and other deposits from the tubes.
This paper highlights the role of hard water in condenser tube fouling, the need to remove scale from condenser tubes and the mechanical cleaning process that was used to restore condenser performance at a prototypical coal fired power station in the United States.
Performance Monitoring of Regenerative System Based on Dominant Factor Method
Authors: Chen Cheng , Zhong Xiaobo , Xiao Jun , Zhu Yong , Jiang Jiao 
Published: September 2017

Safe and efficient operation of a power plant is the system designers’ target. Regenerative system improves the Rankine Cycle efficiency of a power station. However, it is quite difficult to monitor the regenerative system’s performance in an accurate, economical and real-time way at any operation load. There are two main problems about this. One is that most model based on numerical and statistics approaches cannot be explained by the actual operation mechanism of the actual process. The other is that most mechanism models in the past could not be used to monitor the system performance accurately at real-time.
This paper focuses on solving these two problems and finds a better way to monitor the regenerative system’s performance accurately in a real-time by the analysis of the mechanism models and numerical methods. It is called the dominant factor method. Two important parameters (characteristic parameter and dominant factor) and characteristic functions are introduced in this paper. Also, this paper described the analysis process and the model building process.
In the paper, the mathematics model building process is based on a 1000MW unit’s regenerative system. Characteristic functions are built based on the specific operating data of the power unit. Combing the general mechanism model and the characteristic function together, this paper builds up a regenerative system off-design mathematical model. First, this paper proved the model accuracy by computer simulation. Then, the models were used to predict the pressure of the piping outlet, the temperature of the outlet feedwater and drain water of heaters in a real-time by computers. The results show that the deviation rate between the theoretical predictions and the actual operation data is less than 0.25% during the whole operation load range. At last, in order to test the fault identification ability of this model, some real tests were done in this 1000MW power plant during the actual operation period. The performance changes are identified via the difference between the predict value and the real time value. The result of the tests shows that the performance’s gradient change and sudden change could be found by the model result easily.
In order to verify the adaptability of the model, it was used for another 300MW unit, and done some operation test. The results show that this method can also be used for the 300MW unit’s regenerative system. And it can help the operator to recognize the fault heater.
The results of this paper proved that the dominant factor method is feasible for performance monitoring of the regenerative system. It can be used to monitor and find the fault of the regenerative system at any operation load by an accurate and fast way in real-time.
Manual vs. Automatic Boiler Controls: A Historical Perspective From Relevant Codes and Standards
Authors: Bobbitt Brock , Garner Stephen , Cox Brenton , Martens John , Fecke Mark 
Published: September 2017

Advances in computer hardware over the past several decades have helped to expand the capabilities of boiler control systems in power generating applications. These greater capabilities have supported a proliferation of computer controlled boiler functions and, in many cases, replaced human operator functions with automated functions. Nevertheless, the human operator remains a central piece in many modern boiler control systems. One reason the operator is still present in the control room is that computer controls and human operators each have distinct advantages. Consequently, a boiler control system design should balance the best integration of automatic and operator control functions while balancing various requirements and design goals. The following question should then be answered: what roles or functions should be given to the operator vs. to the computer controls?
We will address this question by considering the guidance of relevant codes and standards, which have historically influenced control system design for large boilers in power generating applications. An analysis is performed on current and historically relevant standards and codes, including NFPA 85 and its predecessors, to consider how the guidance has changed along with control system technology. The analysis examines provisions directed toward manual and automatic controls to better understand the types of operations that are best-suited for manual functions versus automatic functions. Over time, NFPA 85 and its predecessors responded to the growing automation capabilities by requiring more automatic controls. While the emphasis placed on automatic controls for safety functions has grown, these standards suggest a balance or combination of automatic and manual controls for safety functions. These concepts are considered relative to those of Inherently Safe Design commonly applied in the chemical process industry.
Knowledge Management in Managing/Optimizing Performance of Power Generating Assets
Authors: Sunder Raj Komandur 
Published: September 2017

In the course of the past decade, there has been increased attention and focus on the challenges facing power plant owners in managing/optimizing performance of their power generating assets. The challenges include aging power plants, changing mix of assets in fleets used for power production, aging workforce, attrition, capturing and retaining knowledge, recruiting new talent, technological changes, obsolescence, economics, environmental regulations, and others. These challenges have resulted in a paradigm shift, creating a need for power plant owners to do more with less, while simultaneously maximizing their operating revenues and return on investment.
This paper provides an overview of the challenges facing the power industry as it grapples with these challenges, and knowledge management strategies to effectively harness the power of human resources, power plant processes and technological advances/tools in managing/optimizing the performance of power generating assets.
Integrated Forward Osmosis/Membrane Distillation Process Technology for Industrial Water Treatment and Reuse
Authors: Kim Gyu Dong , Toy Lora , Hendren Zachary , Choi Young Chul , Lesemann Markus , Buisson Herve 
Published: September 2017

Energy and water are mutually dependent, limited resources that are critical to the development and economic stability of the United States. Energy production requires large volumes of water, and water treatment and distribution requires large amounts of energy. In 2010, water and wastewater treatment accounted for roughly 1.8% of total electricity use in the United States, which corresponded to 69 TWh per year or, in terms of power-generating capacity, over 7.8 GW. Population growth and climate change will result in increased demand on these limited resources, making them not sustainable at present use levels.
In recent years, both forward osmosis (FO) and membrane distillation (MD) have garnered significant attention as next-generation water desalination and reuse technologies with the potential to significantly reduce the energy cost associated with wastewater treatment. Critical technical hurdles and lack of operational understanding, however, have limited development of these individual technologies beyond the laboratory scale. In FO, a draw solution that produces high osmotic pressure but is still easily separable is a major challenge limiting the applicability of this process. The use of MD has been limited by membrane flooding due to oily and surfactant like compounds in industrial wastewaters and the transfer of volatile compounds across the membrane. Combining these technologies in a hybrid process overcomes their individual limitations, while exploiting the benefits of each. Effectively the FO unit pretreats the resulting diluted FO draw solution that is sent to the MD for regeneration via low-grade heat and product water recovery. The regenerated (re-concentrated) draw solution is then recycled to the FO unit. A key advantage of MD is that it is not limited by feed-solution osmotic backpressure, making it ideal for regenerating high-osmotic-pressure FO draw solutions. This, in turn, leads to strong potential for the integrated FO/MD process to treat high-salinity wastewaters that are difficult to treat economically by conventional technologies. The product water leaving the MD unit will be extremely high quality and directly suitable for reuse.
With funding from the U.S. Department of Energy, RTI, in collaboration with industrial partner Veolia, has developed an integrated FO/MD process from lab to small pilot scale. In this presentation, pilot-scale testing efforts of this process technology with real industrial wastewater will be presented. Process performance data obtained on full-size FO and MD membrane modules as well as lessons learned from piloting scale-up and best application areas for the technology will be discussed.
Adding Fish Oil to Whey Protein, Leucine, and Carbohydrate Over a Six-Week Supplementation Period Attenuates Muscle Soreness Following Eccentric Exercise in Competitive Soccer Players
Authors: Philpott Jordan D. , Donnelly Chris , Walshe Ian H. , MacKinley Elizabeth E. , Dick James , Galloway Stuart D.R. , Tipton Kevin D. , Witard Oliver C. 
Published: September 2017

Soccer players often experience eccentric exercise-induced muscle damage given the physical demands of soccer match-play. Since long chain n-3 polyunsaturated fatty acids (n-3PUFA) enhance muscle sensitivity to protein supplementation, dietary supplementation with a combination of fish oil–derived n-3PUFA, protein, and carbohydrate may promote exercise recovery. This study examined the influence of adding n-3PUFA to a whey protein, leucine, and carbohydrate containing beverage over a six-week supplementation period on physiological markers of recovery measured over three days following eccentric exercise. Competitive soccer players were assigned to one of three conditions (2 × 200 mL): a fish oil supplement beverage (FO; n = 10) that contained n-3PUFA (1100 mg DHA/EPA—approximately 550 mg DHA, 550 mg EPA), whey protein (15 g), leucine (1.8 g), and carbohydrate (20 g); a protein supplement beverage (PRO; n = 10) that contained whey protein (15 g), leucine (1.8 g), and carbohydrate (20 g); and a carbohydrate supplement beverage (CHO; n = 10) that contained carbohydrate (24 g). Eccentric exercise consisted of unilateral knee extension/flexion contractions on both legs separately. Maximal force production was impaired by 22% during the 72-hour recovery period following eccentric exercise (p < 0.05). Muscle soreness, expressed as area under the curve (AUC) during 72-hour recovery, was less in FO (1948 ± 1091 mm × 72 h) than PRO (4640 ± 2654 mm × 72 h, p < 0.05) and CHO (4495 ± 1853 mm × 72 h, p = 0.10). Blood concentrations of creatine kinase, expressed as AUC, were ~60% lower in FO compared to CHO (p < 0.05) and tended to be lower (~39%, p = 0.07) than PRO. No differences in muscle function, soccer performance, or blood c-reactive protein concentrations were observed between groups. In conclusion, the addition of n-3PUFA to a beverage containing whey protein, leucine, and carbohydrate ameliorates the increase in muscle soreness and blood concentrations of creatine kinase following eccentric exercise in competitive soccer players.
Cryotherapy Reinvented: Application of Phase Change Material for Recovery in Elite Soccer
Authors: Clifford Tom , Abbott Will , Kwiecien Susan Y. , Howatson Glyn , McHugh Malachy P. 
Published: September 2017

Purpose: To examine whether donning lower-body garments fitted with cooled phase change material (PCM) would enhance recovery after a soccer match. Methods: In a randomized, crossover design, 11 elite soccer players from the reserve squad of a team in the second-highest league in England wore PCM cooled to 15°C (PCMcold) or left at ambient temperature (PCMamb; sham control) for 3 h after a soccer match. To assess recovery, countermovement jump height, maximal isometric voluntary contraction (MIVC), muscle soreness, and the adapted Brief Assessment of Mood Questionnaire (BAM+) were measured before 12, 36, and 60 h after each match. A belief questionnaire was completed preintervention and postintervention to determine the perceived effectiveness of each garment. Results: Results are comparisons between the 2 conditions at each time point postmatch. MIVC at 36 h postmatch was greater with PCMcold versus PCMwarm (P = .01; ES = 1.59; 95% CI, 3.9–17.1%). MIVC also tended to be higher at 60 h postmatch (P = .05; ES = 0.85; 95% CI, −0.4% to 11.1%). Muscle soreness was 26.5% lower in PCMcold versus PCMwarm at 36 h (P = .02; ES = 1.7; 95% CI, −50.4 to −16.1 mm) and 24.3% lower at 60 h (P = .04; ES = 1.1; 95% CI, −26.9 to −0.874 mm). There were no between-conditions differences in postmatch countermovement jump height or BAM+ (P > .05). The belief questionnaire revealed that players felt the PCMcold was more effective than the PCMamb after the intervention (P = .004). Conclusions: PCM cooling garments provide a practical means of delivering prolonged postexercise cooling and thereby accelerate recovery in elite soccer players.
New Records in Human Power
Authors: Haugen Thomas , Paulsen Gøran , Seiler Stephen , Sandbakk Øyvind 
Published: September 2017

Maximal aerobic and anaerobic power are crucial performance determinants in most sport disciplines. Numerous studies have published power data from elite athletes over the years, particularly in runners, cyclists, rowers, and cross-country (XC) skiers. This invited review defines the current “world records” in human upper limits of aerobic and anaerobic power. Currently, max values of ∼7.5 and 7.0 L·min−1 in male XC skiers and rowers, respectively, and/or ∼90 mL·kg−1·min−1 in XC skiers, cyclists, and runners can be described as upper human limits for aerobic power. Corresponding values for women are slightly below 5.0 L·min−1 in rowers and XC skiers and ∼80 mL·kg−1·min−1 in XC skiers and runners. Extremely powerful male athletes may reach ∼85 W·kg−1 in countermovement jump (peak vertical power) and ∼36 W·kg−1 in sprint running (peak horizontal power), cycling (instantaneous power during force–velocity testing from a standing position), and rowing (instantaneous power). Similarly, their female counterparts may reach ∼70 W·kg−1 in countermovement jump and ∼30 W·kg−1 in sprint running, cycling, and rowing. The presented values can serve as reference values for practitioners and scientists working with elite athletes. However, several methodological considerations should be taken into account when interpreting the results. For example, calibrated apparatus and strict procedures are required to ensure high measurement validity and reliability, and the sampling rate for anaerobic power assessments must be strictly predetermined and carefully measured. Doping is also a potential confounding factor when interpreting the human upper limits of aerobic and anaerobic power.
Whole-Body Vibration on Performance of Quadriceps After ACL Reconstruction: A Blinded Randomized Controlled Trial
Authors: da Costa Karinna Sonálya Aires , Borges Daniel Tezoni , de Brito Macedo Liane , de Almeida Lins Caio Alano , Brasileiro Jamilson Simões 
Published: September 2017

Context: Whole-body vibration (WBV) has been widely used in clinical and sport practice. These devices produce constant vibrations, originating symmetrical waves that move along the vertical axis. It is suggested that mechanical stimuli produced by high vibration can be an alternative to improve neuromuscular performance and balance in different populations. However, there is still a lack of consensus in the literature regarding neurophysiological responses in the skeletal muscle immediately after the use of WBV, specifically in individuals subjected to anterior cruciate ligament reconstruction. Objective: To investigate the immediate effects of WBV on neuromuscular performance of the quadriceps femoris and postural oscillation of individuals subjected to anterior cruciate ligament reconstruction. Design: This is a blinded randomized controlled trial. Setting: University laboratory. Participants: Forty-four men. Intervention: Participants were randomized into 2 groups: control group (n = 22, exercise protocol on the vibrating platform turned off) and WBV group (n = 22, exercises on the vibrating platform turned on, at a frequency of 50 Hz and amplitude of 4 mm). Main Outcome Measures: The volunteers underwent a dynamometric evaluation of the quadriceps femoris and electromyographic activity of vastus lateralis and vastus medialis muscles, in addition to oscillation of the center of pressure at 2 different moments: before and immediately after the intervention protocol. Results: The intragroup comparison evidenced differences between preassessments and postassessments for the variables of laterolateral amplitude, peak torque, and total work. However, no significant difference was observed in the intergroup comparison after WBV protocol. Conclusion: The use of WBV did not immediately alter the performance of the quadriceps femoris and the electromyographic activity of vastus lateralis and vastus medialis muscles. In addition, it also did not interfere with pressure center oscillation of individuals subjected to anterior cruciate ligament reconstruction.
How Does the Relationship Between Motor Skill Performance and Body Mass Index Impact Physical Activity in Preschool Children?
Authors: Guo Haixia , Schenkelberg Michaela A. , O’Neill Jennifer R. , Dowda Marsha , Pate Russell R. 
Published: September 2017

Purpose: To determine if weight status modifies the relationship between motor skill (MS) performance and physical activity (PA) in preschoolers. Methods: Preschoolers (N = 227, age 3–5 y) were recruited from 22 preschools. Preschoolers’ MS (locomotor, object control, and total MS) were assessed with the Children’s Activity and Movement in Preschool Study MS protocol. PA was measured by accelerometry. Mixed linear models were used to examine the relationship of MS performance and body mass index (BMI) z score to PA. Models were adjusted for age, race, sex, and parent education, with preschool as a random effect. Results: There was a significant correlation between MS performance and PA (r = .14–.17, P < .05). A significant interaction was observed between BMI z score and object control, and between BMI z score and total MS score on PA (P = .03). Preschoolers with higher BMI z scores and high object control scores engaged in significantly (P = .03) more PA than preschoolers with lower BMI z scores and high object control scores (PA = 15.04 min/h and 13.54 min/h, respectively). Similarly, preschoolers with higher BMI z scores and high total MS scores spent significantly (P = .01) more time in PA compared with those with lower BMI z scores and high total MS scores (PA = 15.65 min/h and 13.91 min/h, respectively). Conclusion: Preschool children’s MS performance is positively correlated with PA, and BMI z score modified the relationship between MS performance and PA.
Bone Turnover Markers and Lean Mass in Pubescent Boys: Comparison Between Elite Soccer Players and Controls
Authors: Nebigh Ammar , Abed Mohamed Elfethi , Borji Rihab , Sahli Sonia , Sellami Slaheddine , Tabka Zouhair , Rebai Haithem 
Published: September 2017

The aim of this study was to examine the relationship between bone mass and bone turnover markers with lean mass (LM) in pubescent soccer players. Two groups participated in this study, which included 65 elite young soccer players who trained for 6–8 hours per week and 60 controls. Bone mineral density; bone mineral content in the whole body, lower limbs, lumbar spine, and femoral neck; biochemical markers of osteocalcin; bone-specific alkaline phosphatase; C-telopeptide type I collagen; and total LM were assessed. Young soccer players showed higher bone mineral density and bone mineral content in the whole body and weight-bearing sites (P < .001). Indeed, the total LM correlated with whole-body bone mineral density and bone mineral content (P < .001). There were significant differences within the bone formation markers and osteocalcin (formation)/C-telopeptide type I collagen (resorption) ratio between young soccer players compared with the control group, but no significant difference in C-telopeptide type I collagen was observed between the 2 groups. This study showed a significant positive correlation among bone-specific alkaline phosphatase, osteocalcin, and total LM (r = .29; r = .31; P < .05) only for the young soccer players. Findings of this study highlight the importance of soccer practice for bone mineral parameters and bone turnover markers during the puberty stage.