Similarities and differences of pumping conventional and self-compacting concrete

In Practice, Self-Compacting Concrete (SCC) is Considered as a Simple Extension of Conventional Vibrated Concrete (CVC) When Pumping is Concerned. the Same Equipment, Materials, Pumping Procedures and Guidelines Used for CVC Are Applied When Pumping SCC. on the Other Hand, It Has Been Clearly Shown that the Rheological Properties and the Mix Design of SCC Are Different Than CVC. Can the Same Pumping Principles Employed for CVC Be Applied for SCC? This Paper Compares the Some Published Results of Pumping of CVC with Those for SCC. a First Striking Difference between Pumping of CVC and SCC is the Flow Behaviour in the Pipes. the Flow of CVC is a Plug, Surrounded by a Lubricating Layer, While during the Flow of SCC, Part of the Concrete Volume itself is Sheared Inside the Pipe. as a Result, the Importance of Viscosity Increases in Case of SCC. Due to the Low Yield Stress of SCC, the Behaviour in Bends is Different, But Quite Complex to Study. Due to the Lower Content of Aggregate and Better Stability of SCC, as It is Less Prone to Internal Water Migration, Blocking is Estimated to Occur at Lower Frequency in Case of SCC. © RILEM 2010

Monitoring riverine fish communities through eDNA metabarcoding:Determining optimal sampling strategies along an altitudinal and biodiversity gradient

Monitoring aquatic biodiversity through DNA extracted from environmental samples (eDNA) combined with high-throughput sequencing, commonly referred to as eDNA metabarcoding, is increasing in popularity within the scientific community. However, sampling strategies, laboratory protocols and analytical pipelines can influence the results of eDNA metabarcoding surveys. While the impact of laboratory protocols and analytical pipelines have been extensively studied, the importance of sampling strategies on eDNA metabarcoding surveys has not received the same attention. To avoid underestimating local biodiversity, adequate sampling strategies (i.e. sampling intensity and spatial sampling replication) need to be implemented. This study evaluated the impact of sampling strategies along an altitudinal and biodiversity gradient in the upper section of the Murrumbidgee River (Murray-Darling Basin, Australia). An eDNA metabarcoding survey was used to determine the local fish biodiversity and evaluate the influence of sampling intensity and spatial sampling replication on the biodiversity estimates. The results show that optimal eDNA sampling strategies varied between sites and indicate that river morphology, species richness and species abundance affect the optimal sampling intensity and spatial sampling replication needed to accurately assess the fish biodiversity. While the generality of the patterns will need to be confirmed through future studies, these findings provide a basis to guide future eDNA metabarcoding surveys in river systems

Development and Applications of the Intrinsic Model for Formwork Pressure of Self-Consolidating Concrete

Self-consolidating concrete (SCC) is a recently developed innovative construction material. SCC fills in a formwork without any vibrating consolidation, which allows us to eventually achieve robust casting. However, high formwork lateral pressure exerted by SCC is a critical issue regarding its application as cast-in-place concrete. In order to control the risk caused by high formwork pressure, a comprehensive prediction model for the pressure was previously proposed, investigated, and validated with various SCC mixtures. The model was originally designed to simulate the intrinsic pressure response of SCC mixtures while excluding other extrinsic influencing factors such as friction and flexibility of the formwork. The model was then extended to consider extrinsic factors such as friction between SCC mixtures and formwork. In addition, other interesting topics for peak formwork pressure and mineral admixture effects were summarized in the paper.open5

An Exploratory Analysis of Relationships between Physical Activity, General Health and Fitness, and Job-Specific Fitness in Law Enforcement Officers

The physical fitness of law enforcement officers (LEO) generally declines over their career. Sedentary behaviors contribute to these declines, which could impact job performance. Wellness programs often encourage physical activity (PA) participation in officers with the belief that this will benefit general and job-specific fitness. Greater evidence for this assertion could support wellness program implementation. PURPOSE: To derive relationships between PA with general and job-specific fitness in LEO. METHODS: Data from 60 LEO (48 males, 12 females) from one agency were analyzed. Officers completed a questionnaire assessing PA (weekly strenuous, moderate, and mild exercise sessions; activity score), with 3 added items for resistance training (RT) (likelihood of RT; average RT sessions per week over past 3 months; number of RT sessions in past 7 days). General health and fitness tests included resting heart rate (RHR), blood pressure, waist-to-hip ratio (WHR), sit-and-reach, grip strength, 60-s push-ups, 60-s sit-ups, and YMCA step test. Job-specific fitness was measured by a 99-yard obstacle course, 165-lb body drag, 6-foot chain link fence climb, 6-foot solid wall climb, and 500-yard run. Partial correlations controlling for sex calculated relationships between PA with general and job-specific fitness (p<0.05). The sample was also split into quartiles based on PA activity score. Univariate analyses, with sex as a covariate and Bonferroni post hoc analyses, derived between-quartile fitness differences. RESULTS: Weekly strenuous PA sessions related to RHR (r=-0.36), WHR (r=-0.29), push-ups (r=0.31), and sit-ups (r=0.33). Activity score related to RHR (r=-0.27) and sit-ups (r=0.35). RT likelihood related to RHR (r=-0.40), WHR (r=-0.33), push-ups (r=0.39), and sit-ups (r=0.40); 3-month RT frequency related to RHR (r=-0.41), push-ups (r=0.43), and sit-ups (r=0.31); weekly RT frequency related to push-ups (r=0.39) and sit-ups (r=0.35). There were no significant relationships for PA and job-specific fitness. The top quartile had a lower RHR than the bottom quartile (p=0.03) and completed more sit-ups than the bottom two quartiles (p≤0.03). While there were no significant between-quartile differences in job-specific fitness, there was a tendency for higher quartiles to be faster (Figure 1). CONCLUSIONS: Officers who completed more weekly strenuous PA had a lower RHR and WHR, and better muscular endurance (push-ups/sit-ups). Greater RT frequency related to lower RHR and better muscular endurance. While there were no significant relationships or between-group differences when officers were split into PA quartiles, officers in higher quartiles tended to be faster in the job tasks. However, general PA alone may not be enough to maintain job-specific fitness. PRACTICAL APPLICATIONS: Greater PA and RT frequency may benefit RHR, WHR, and muscular endurance. Some positive impacts to job performance may occur, but LEO may require job-specific fitness training