bluuebunny/crossref_metadata_2025 huggingface dataset:
Influences of Load Command Signals on the Operation Characteristics of Coal-Fired Power Plants During Loading up Processes
Authors: Wang Chaoyang , Liu Yiwen , Liu Ming , Chong Daotong , Yan Junjie
Published: September 2017

In recent years an increasing number of coal-fired power plants are forced to take part in load cycling to balance the electricity demands and supplies in China. Therefore, the investigation of energy consumption characteristics of power plants during transient processes is necessary and valuable. In this paper, the loading up processes of a power plant with several formats of load commands, such as linear, parabolic, sine and exponential functions were simulated, and the energy consumption characteristics of the power plant were presented. Furthermore, the operation characteristics including flexibility, safety and generation cost were compared. Results show that: when the unit increases load with the same average cycling loading rate, the max difference of standard coal consumption rates is 1.03 g/(kW h), which decreases with the increase of average cycling rate. The excellent signal formats have the following features: the instantaneous cycling rates are small in the ending of a transient process while they have high values in the beginning and mid-stage of the process. (CSPE)
Characterization of Crack Tip Damage Zone Formation on Alloy 625 During Fatigue Crack Growth at 750°C by Transmission EBSD Method
Authors: Ozawa Yuji , Ishikawa Tatsuya , Takeda Yoichi
Published: September 2017

In order to clarify the mechanism of fatigue crack growth in alloy 625, which is a candidate material for use in advanced ultra supercritical power plants, the crack tip damage zone formation after a crack growth test conducted in high temperature steam was investigated. It was observed that the oxide thickness at the crack tip tended to increase with decreasing cyclic loading frequency. The crack path was a mix of transgranular and intergranular fractures. According to the grain reference orientation deviation (GROD) maps, it was revealed that the density of geometrically necessary dislocations (GNDs) in the matrix along the crack path and ahead of crack tip increased with an increase in the fatigue crack growth rate (FCGR) due to environmental effects. It was observed that (1) mobile dislocations at the crack surface were blocked due to the thick oxide layer, resulting in an increase in the density of GNDs, and (2) an increase in the density of GNDs might induce stress concentration at the crack tip, deformation twinning, and the acceleration of FCGRs.
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.
Experiment and Mechanism Study on the Effect of Coal Ash on the Capture of Alkali Metals in Zhundong Coal
Authors: Xinglei Hu
Published: September 2017

A large number of Xinjiang Zhundong coal was found in China. Its high content of alkali metals can cause serious fouling/slagging problems which may lead to economic losses. It is significant to control the release of alkali metals from Zhundong coal during the combustion. Si-Al additives are used to capture Na released from the Zhundong coal. In this work, a combination of experimental research and quantum chemical calculation was used to study the effect of coal ash on the capture of alkali metal in Zhundong high alkali Coal and the related mineral evolution mechanism during melting processes. The experiments were done with Zhundong coal/coal ash mixtures at 900–1200°C. The behavior mechanism of coal ash capturing alkali metals was analyzed from the perspective of mineral microstructure features by using XRD, ICP and quantum chemical calculation methods. The results show that during the process of combustions, complex chemical reactions occur among minerals after sodium is released from the coal and captured by the coal ash. The coal ash’s ability to capture sodium in Zhundong high alkali coal rises firstly, and then gradually decreases with the rise of temperature. It shows the best capture performance for sodium at 1000∼1100°C. The maximum efficiency of sodium absorption can reach to 50.6%. The coal ash shows a rather high efficiency compared with other additives. Furthermore, metals in Zhundong coal have opposite directions of migration. The Na, K, Al, Ca, and Mg migrated to the coal ash far away from the reaction interface, and the Fe and Mn were moved to the coal from the reaction interface. The original minerals of Zhundong coal mainly include calcium sulfate hydrate, quartz and kaolinite. Investigating the capture mechanism, it indicates that O (26) and O (22) in kaolinite have electrophilic reaction with Na+ and K+ easily, which would promote the rupture of aluminum-oxygen bonds. The O2- of alkali metal or alkaline earth metal oxide would easily have nucleophilic reaction with Si (6) and Si (8) and prompt the rupture of bridging oxygen bonds (Si-O-Si). Kaolinite would be transformed into some other minerals that contains Na+ or K+ which have trend to form eutectics or evaporate into the flue gas easily, the degree of fouling and slagging on heating surface can be reduced based on these two most easily reaction paths.
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.
Comparative Assessment of Different Types of Ocean Compressed Air Energy Storage Systems Based on Exergy Analysis
Authors: Patil Vikram C. , Ro Paul I.
Published: September 2017

Ocean compressed air energy storage (OCAES) is a promising large-scale energy storage concept. Different types of OCAES viz. - Diabatic, adiabatic and isothermal are possible based on the handling of heat in the system. In diabatic OCAES, compressed air is cooled in a cooler and heated using external heat source before transport to the expander. In Adiabatic OCAES, heat from the compressed air is stored in a thermal energy storage (TES) and reused to reheat compressed air before sending it to the expander. In Isothermal OCAES, air is compressed and expanded isothermally which results in the least compression work and highest expansion work. These OCAES configurations are assessed using exergy analysis in this paper. The exergy efficiency of individual components, exergy flow and overall efficiencies of diabatic, adiabatic and isothermal OCAES are presented. Results show that adiabatic OCAES shows improved efficiency over diabatic OCAES by storing thermal exergy of compressed air in TES and isothermal OCAES shows significantly higher efficiency over adiabatic and diabatic OCAES.
Modeling of a Low Cost Thermal Energy Storage System to Enhance Generation From Small Hydropower Systems
Authors: Ip Peggy P. , Houssainy Sammy , Kavehpour H. Pirouz
Published: September 2017

Undeveloped small hydropower generation sites are abundant throughout the water conveyance infrastructure and natural rivers in the United States. Due to its small scale, micro-hydro development requires substantial upfront capital costs, maintenance and operation costs for customized engineering and construction. The significant investments required for developing small hydropower are inhibiting for utilities, residential and commercial users to adopt. An inexpensive energy storage system and a well-designed power controls system can be integrated with small hydropower sites to increase its cost-effectiveness and reliability. This paper introduces the concept of storing low-power generated from small hydro turbines during long off-peak periods and dispatching at high-power as grid-quality electricity during peak periods. The use of an ultra-low cost thermal energy storage (ULCTES) system is examined. Boosting the power output for small hydro generation allows commercial users to avoid significant demand charges during operation, making small hydro an attractive cost saving strategy and therefore breaking down the cost barrier. The ULCTES operates much like a bulk power production unit and a peaker plant, in which it is capable of dispatching constant power over a long period during peak periods when conventional sources are unavailable. Improvements in system reliability and economic value are evaluated using microgrid optimization software HOMER Energy. In particular, two cases are studied with variations in types of end users and energy management goals. Energy costs savings, demand charges savings and renewable energy penetration are determined. Distributed energy storage systems are shown to reduce energy costs and increase the renewable energy penetration for commercial users. With ULCTES, microgrids have the flexibility to manage fluctuating renewable energy generation as well as respond to rapidly changing loads on a daily basis. A larger hydroelectricity system is shown to be more feasible with distributed energy storage systems for isolated users without any connection to the grid.
Blade Faults Diagnosis in Power Generation Gas Turbines
Authors: Lim Meng Hee , Leong Salman , Hui Kar Hoou
Published: September 2017

This paper presents a case study in managing the dilemma of whether to resume or stop the operation of a power generation gas turbine with suspected blade faults. Vibration analysis is undertaken on the vibration signal of the gas turbine, to obtain an insight into the health condition of the blades before any decision is made on the operation of the machine. Statistical analysis is applied to study the characteristics of the highly unstable blade pass frequency (BPF) of the gas turbine and to establish the baseline data used for blade fault assessment and diagnosis. Based on the excessive increase observed on specific BPF amplitudes in comparison to the statistical baseline data, rubbing at the compressor blade is suspected. An immediate overhaul is therefore warranted, and the results from the inspection of the machine confirm the occurrence of severe rubbing at the compressor blades and labyrinth glands of the gas turbine. In conclusion, statistical analysis of BPF amplitude is found to be a viable tool for blade fault diagnosis in industrial gas turbines.
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.
Pressure reciprocity calibration of a MEMS microphone
Authors: Wagner Randall P. , Fick Steven E.
Published: September 2017

This article reports the first use of the pressure reciprocity technique to calibrate a micro-electromechanical system (MEMS) microphone. This standardized primary calibration method is conventionally used to calibrate laboratory standard microphones. Results for the pressure reciprocity calibration of a MEMS microphone and two laboratory standard microphones are presented for the frequency range 100–10 000 Hz. Because the amplifier in the MEMS microphone package prevents reciprocal operation, this microphone was used only as a receiver of sound. A description of the procedure is presented along with checks of the measurement results and data regarding the uncertainties of these results.
Multi Criteria Decision-Making: Ticket Sales Outsourcing in an NCAA Division I Athletic Department
Authors: Lee Seungbum , Juravich Matthew
Published: September 2017

Outsourcing in sport is not a new phenomenon. Specifically, outsourcing in intercollegiate sport has become common among athletic departments across the NCAA. While outsourcing can be employed to generate increased revenues via enhanced sales, marketing, or fundraising functions, many midmajor institutions are utilizing outsourcing partners exclusively to manage ticket sales. As such, this case presents a scenario in which an athletic director and her management team are faced with assessing three options related to ticket sales outsourcing at a midmajor NCAA Division 1 institution. Utilizing the lens of multi criteria decision-making, financial, nonfinancial, and circumstantial data are provided for readers to address an outsourcing decision in the context of intercollegiate athletics. By examining three options including maintaining the status quo, considering another outsourcing partner, or bringing ticket sales operations in-house, this case provides an opportunity for students to investigate the role of ticket sales outsourcing as it relates to revenue generation, a pertinent issue for athletic departments across the NCAA.
Single Nucleotide Polymorphisms in Carnosinase Genes (CNDP1 and CNDP2) are Associated With Power Athletic Status
Authors: Guilherme João Paulo Limongi França , Lancha Antonio Herbert
Published: September 2017

Carnosine (β-alanyl-L-histidine), abundantly found in skeletal muscle, plays an important role during exercise, especially for high-intensity contractions. Variability in muscle carnosine content between individuals exists and may also be explained by different genetic bases, although no study has addressed the association of polymorphisms in genes related to carnosine metabolism in athletes. This study aimed to investigate the frequency of single nucleotide polymorphisms (SNPs) in the carnosinase genes (CNDP1 and CNDP2) in a large Brazilian cohort of athletes and nonathletes. Eight SNPs were compared between a representative cohort of elite athletes from Brazil (n = 908) and a paired group of nonathletes (n = 967). The athletes were stratified into three groups: endurance (n = 328), power (n = 415), and combat (n = 165). The CNDP2 rs6566810 (A/A genotype) is overrepresented in endurance athletes, but only in international-level endurance athletes. Three SNPs (CNDP2 rs3764509, CNDP2-CNDP1 rs2346061, and CNDP1 rs2887) were overrepresented in power athletes compared with nonathletes. Carriers of the minor allele had an increased odds ratio of being a power athlete. For the rs2346061, no significant difference was observed in genotype frequencies between power and combat sports athletes, but for rs2887 the power and combat groups showed an inverse genotype distribution. In conclusion, we found that minor alleles carriers for CNDP2 rs3764509 (G-allele), CNDP2-CNDP1 rs2346061 (C-allele), and CNDP1 rs2887 (A-allele) are more likely to be a power athlete. These polymorphisms may be novel genetic markers for power athletes. Furthermore, these results are suggestive of a distinct CNDP genotype for sporting development.
Sweat Sodium Concentration: Inter-Unit Variability of a Low Cost, Portable, and Battery Operated Sodium Analyzer
Authors: Goulet Eric D.B. , Baker Lindsay B.
Published: September 2017

The B-722 Laqua Twin is a low cost, portable, and battery operated sodium analyzer, which can be used for the assessment of sweat sodium concentration. The Laqua Twin is reliable and provides a degree of accuracy similar to more expensive analyzers; however, its interunit measurement error remains unknown. The purpose of this study was to compare the sodium concentration values of 70 sweat samples measured using three different Laqua Twin units. Mean absolute errors, random errors and constant errors among the different Laqua Twins ranged respectively between 1.7 mmol/L to 3.5 mmol/L, 2.5 mmol/L to 3.7 mmol/L and –0.6 mmol/L to 3.9 mmol/L. Proportional errors among Laqua Twins were all < 2%. Based on a within-subject biological variability in sweat sodium concentration of ± 12%, the maximal allowable imprecision among instruments was considered to be £ 6%. In that respect, the within (2.9%), between (4.5%), and total (5.4%) measurement error coefficient of variations were all < 6%. For a given sweat sodium concentration value, the largest observed difference in mean and lower and upper bound error of measurements among instruments were, respectively, 4.7 mmol/L, 2.3 mmol/L, and 7.0 mmol/L. In conclusion, our findings show that the interunit measurement error of the B-722 Laqua Twin is low and methodologically acceptable.
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.
Optimizing Heat Acclimation for Endurance Athletes: High- Versus Low-Intensity Training
Authors: Schmit Cyril , Duffield Rob , Hausswirth Christophe , Brisswalter Jeanick , Le Meur Yann
Published: September 2017

Purpose: To determine the effect of high- versus low-intensity training in the heat and ensuing taper period in the heat on endurance performance. Methods: In total, 19 well-trained triathletes undertook 5 days of normal training and a 1-wk taper including either low- (heat acclimation [HA-L], n = 10) or high-intensity (HA-H, n = 9) training sessions in the heat (30°C, 50% relative humidity). A control group (n = 10) reproduced their usual training in thermoneutral conditions. Indoor 20-km cycling time trials (35°C, 50% relative humidity) were performed before (Pre) and after the main heat exposure (Mid) and after the taper (Post). Results: Power output remained stable in the control group from Pre to Mid (effect size: −0.10 [0.26]) and increased from Mid to Post (0.18 [0.22]). The HA-L group demonstrated a progressive increase in performance from Pre to Mid (0.62 [0.33]) and from Mid to Post (0.53 [0.30]), alongside typical physiological signs of HA (reduced core temperature and heart rate and increased body-mass loss). While the HA-H group presented similar adaptations, increased perceived fatigue and decreased performance at Mid (−0.35 [0.26]) were evidenced and reversed at Post (0.50 [0.20]). No difference in power output was reported at Post between the HA-H and control groups. Conclusion: HA-H can quickly induce functional overreaching in nonacclimatized endurance athletes. As it was associated with a weak subsequent performance supercompensation, coaches and athletes should pay particular attention to training monitoring during a final preparation in the heat and reduce training intensity when early signs of functional overreaching are identified.
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.
Transformational Coaching Workshop: Applying a Person-Centred Approach to Coach Development Programs
Authors: Turnnidge Jennifer , Côté Jean
Published: September 2017

It is well established that coach learning and athlete outcomes can be enhanced through participation in Coach Development Programs (CDPs). Researchers advocate that the quality of CDPs can be improved by: (a) placing a greater emphasis on facilitating coaches’ interpersonal behaviours (Lefebvre, Evans, et al., 2016), (b) using appropriate and systematic evaluation frameworks to guide the evaluation of interpersonally-focused CDPs (Evans et al., 2015), and (c) incorporating behaviour change theories into the design and implementation of these CDPs (Allan et al., 2017). In doing so, the relevance of CDP content and the uptake of this content among coaching practitioners may be enhanced. Transformational leadership theory provides a valuable guiding framework for designing CDPs that aim to promote positive development in youth sport. Thus, the goal of the present paper is to outline the development of a novel, evidence-informed CDP: The Transformational Coaching Workshop and to provide practical strategies for the implementation of this workshop.
What Is the Most Effective Training Approach for Preventing Noncontact ACL Injuries in High School–Aged Female Athletes?
Authors: Willadsen Erica M. , Zahn Andrea B. , Durall Chris J.
Published: September 2017

Clinical Scenario: A variety of training approaches have been adopted in anterior cruciate ligament (ACL) prevention programs, including neuromuscular control training, core stability training, balance training, and plyometric exercise. This review was conducted to determine if current evidence supports one of these training approaches over the others for reducing noncontact ACL injuries in adolescent female athletes. Focused Clinical Question: What is the most effective training approach for preventing noncontact ACL injuries in adolescent and/or high school–aged female athletes? Summary of Key Findings: A literature search generated 2 level 1b randomized control trials and 1 level 2b cohort study. Plyometric training resulted in decreased knee valgus during landing in 3 studies and increased knee flexion at landing in 2 studies. Balance training or neuromuscular training led to decreased knee valgus and increased knee-flexion angles with landing in 2 studies. Core stability training had conflicting effects on knee valgus and knee-flexion angles at landing, with 1 study reporting no effect and another reporting an undesirable decrease in knee joint flexion angle at landing. Clinical Bottom Line: Based on this review, plyometric training, balance training, and neuromuscular training approaches appear sensible to include in ACL prevention programs for female athletes to help decrease knee valgus and knee flexion during landing. Core stability training may be somewhat beneficial for decreasing knee valgus angles at landing, although may have nominal or even deleterious effects on knee-flexion angle at landing, and thus should be implemented with caution. Strength of Recommendation: Our recommendations were derived from the results of 2 level 1b randomized control trials and 1 level 2b cohort study.
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.
Impact of Scoliosis Severity on Functional Capacity in Patients With Adolescent Idiopathic Scoliosis
Authors: Saraiva Bruna M.A. , Araujo Geferson S. , Sperandio Evandro F. , Gotfryd Alberto O. , Dourado Victor Z. , Vidotto Milena C.
Published: September 2017

Purpose: The aim of this study is to evaluate the walked distance and physiological responses during incremental shuttle walk test in patients with different degrees of adolescent idiopathic scoliosis (AIS). Methods: We evaluated 20 healthy teenagers and 46 patients with AIS; they were divided into 2 groups: AIS > 45° and AIS < 45°. The volunteers performed an incremental shuttle walk test, and the following physiological responses were quantified: oxygen consumption, tidal volume, ventilation, and the incremental shuttle walked distance. Respiratory muscle strength was quantified, pulmonary function test was performed, and the forced vital capacity and expiratory volume in the first second were obtained. Results: Patients with AIS > 45° presented significant reduced incremental shuttle walked distance compared with the AIS < 45° and control group [447 (85), 487 (95), and 603 (85), respectively]. Patients with AIS also showed reduced forced vital capacity (P = .001) and expiratory volume in the first second (P = .005) compared with control group. Moderate correlations between forced vital capacity (r = −.506) and tidal volume (r = −.476) with scoliosis angles were found. Conclusions: The incremental shuttle walk test was capable of identifying reduced functional capacity in patients with different degrees of AIS. Moreover, the severity of spinal curvature may exert influence on ventilatory and metabolic variables.
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.
Bacterial
d
-amino acids suppress sinonasal innate immunity through sweet taste receptors in solitary chemosensory cells
Authors: Lee Robert J. , Hariri Benjamin M. , McMahon Derek B. , Chen Bei , Doghramji Laurel , Adappa Nithin D. , Palmer James N. , Kennedy David W. , Jiang Peihua , Margolskee Robert F. , Cohen Noam A.
Published: September 2017

Staphylococcus
-derived
d
-amino acids reduce innate immune responses in the nasal epithelium by stimulating the sweet taste receptor.
Performance of a postnatal metabolic gestational age algorithm: a retrospective validation study among ethnic subgroups in Canada
Authors: Hawken Steven , Ducharme Robin , Murphy Malia S Q , Atkinson Katherine M , Potter Beth K , Chakraborty Pranesh , Wilson Kumanan
Published: September 2017

Objectives

Biological modelling of routinely collected newborn screening data has emerged as a novel method for deriving postnatal gestational age estimates. Validation of published models has previously been limited to cohorts largely consisting of infants of white Caucasian ethnicity. In this study, we sought to determine the validity of a published gestational age estimation algorithm among recent immigrants to Canada, where maternal landed immigrant status was used as a surrogate measure of infant ethnicity.

Design

We conducted a retrospective validation study in infants born in Ontario between April 2009 and September 2011.

Setting

Provincial data from Ontario, Canada were obtained from the Institute for Clinical Evaluative Sciences.

Participants

The dataset included 230 034 infants born to non-landed immigrants and 70 098 infants born to immigrant mothers. The five most common countries of maternal origin were India (n=10 038), China (n=7468), Pakistan (n=5824), The Philippines (n=5441) and Vietnam (n=1408). Maternal country of origin was obtained from Citizenship and Immigration Canada’s Landed Immigrant Database.

Primary and secondary outcome measures

Performance of a postnatal gestational age algorithm was evaluated across non-immigrant and immigrant populations.

Results

Root mean squared error (RMSE) of 1.05 weeks was observed for infants born to non-immigrant mothers, whereas RMSE ranged from 0.98 to 1.15 weeks among infants born to immigrant mothers. Area under the receiver operating characteristic curve for distinguishing term versus preterm infants (≥37 vs <37 weeks gestational age or >34 vs ≤34 weeks gestational age) was 0.958 and 0.986, respectively, in the non-immigrant subgroup and ranged from 0.927 to 0.964 and 0.966 to 0.99 in the immigrant subgroups.

Conclusions

Algorithms for postnatal determination of gestational age may be further refined by development and validation of region or ethnicity-specific models. However, our results provide reassurance that an algorithm developed from Ontario-born infant cohorts performs well across a range of ethnicities and maternal countries of origin without modification.
Biopsychosocial factors associated with non-recovery after a minor transport-related injury: protocol for a systematic review
Authors: Samoborec Stella , Ruseckaite Rasa , Romero Lorena , Evans Sue M
Published: September 2017

Introduction

Globally, road transport accidents contribute substantially to the number of deaths and also to the burden of disability. Up to 50 million people suffer a transport-related non-fatal injury each year, which often leads to long-term disability. It has been shown that substantial number of people with minor injuries struggle to recover and the reasons are still not well explored.

Despite the high prevalence, little is known about the factors hindering recovery following minor traffic-related injuries. The aim of this paper is to present a protocol for the systematic review aiming to understand biopsychosocial factors related to non-recovery and identify current gaps in the literature.

Methods and analysis

The review will be conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol guidelines. A search of the electronic databases, MEDLINE, EMBASE, Cochrane Central Register of Controlled trials, will be undertaken, in addition to Google Scholar and grey literature to identify studies in period from 2006 to 2016. Quantitative and qualitative research articles describing and identifying biopsychosocial factors associated with non-recovery and health outcomes such as pain, disability, functional recovery, health-related quality of life, post-traumatic stress disorder, depression, anxiety and return to work will be included. A conceptual framework developed to identify biopsychosocial factors will be applied to assure defined criterion.

At present, there is little anticipation for meta-analyses due to the heterogeneity of factors and outcomes assessed. Therefore, a narrative synthesis based on study findings will be conducted.

Ethics and dissemination

Ethical approval is not required as primary data will not be collected. Review results will be published as a part of thesis, peer-reviewed journal and conferences.

Trialregistration number

PROSPEROregistration number: CRD42016052276.