Acute Caffeine Ingestion Increases Velocity and Power in Upper and Lower Body Free-Weight Resistance Exercises

International Journal of Exercise Science 12(2): 1280-1289, 2019. The purpose of this study was to examine the acute effects of caffeine supplementation on velocity and power output during bench press and back squat exercises. Resistance trained males (n = 12) consuming less than 300 mg of caffeine daily, were recruited for this study. In a blinded crossover study design, participants supplemented with 6 mg· kg-1 caffeine or placebo (placebo, gluten-free cornstarch) 60 min prior to exercise. Participants completed 3 × 1 repetition with maximum explosive intent at 80% of their 1-RM for bench and squat exercises with two minute rest periods between each repetition. A linear position transducer was used to measure power and velocity of barbell movement. Each trial was separated by a 72 h washout period. Results indicated that mean velocity (p = 0.027; ES = 1.04) and mean power (p = 0.008; ES = 0.24) were higher during bench press exercise with caffeine versus placebo. Furthermore, mean velocity (p = 0.005; ES=1.06) and mean power (p = 0.020; ES = 0.71) values were higher for back squat exercise with caffeine versus placebo. This study suggests that caffeine ingestion imposes ergogenic benefits by increasing velocity and power in both upper and lower body resistance exercises. However, caffeine had a larger effect on lower body power output versus upper body exercise. Results may hold important implications for using caffeine during training

Microchannel cooling for the LHCb VELO Upgrade I

The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase \cotwo for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale application of this technology to date. Production of the microchannel coolers was completed in July 2019 and the assembly into cooling structures was completed in September 2021. This paper describes the R\&D path supporting the microchannel production and assembly and the motivation for the design choices. The microchannel coolers have excellent thermal peformance, low and uniform mass, no thermal expansion mismatch with the ASICs and are radiation hard. The fluidic and thermal performance is presented.Comment: 31 pages, 27 figure

Microchannel cooling for the LHCb VELO upgrade I

The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale application of this technology to date. Production of the microchannel coolers was completed in July 2019 and the assembly into cooling structures was completed in September 2021. This article describes the R&D path supporting the microchannel production and assembly and the motivation for the design choices, together with the achieved fluidic and thermal performance. The Thermal Figure of Merit of the microchannel coolers is measured on the final modules to be between 1.5 and 3.5 K cm W, depending on glue thickness. The microchannel coolers constitute 18% of the total radiation length of the VELO and less than 2% of the material seen before the second measured point on the tracks. Microchannel cooling is well suited to the VELO implementation due to the uniform mass distribution, close thermal expansion match with the module components and resistance to radiation