Energy dataset of Frontier supercomputer for waste heat recovery.

The Hewlett Packard Enterprise-Cray EX Frontier is the world's first and fastest exascale supercomputer, hosted at the Oak Ridge Leadership Computing Facility in Tennessee, United States. Frontier is a significant electricity consumer, drawing 8-30 MW; this massive energy demand produces significant waste heat, requiring extensive cooling measures. Although harnessing this waste heat for campus heating is a sustainability goal at Oak Ridge National Laboratory (ORNL), the 30 °C-38 °C waste heat temperature poses compatibility issues with standard HVAC systems. Heat pump systems, prevalent in residential settings and some industries, can efficiently upgrade low-quality heat to usable energy for buildings. Thus, heat pump technology powered by renewable electricity offers an efficient, cost-effective solution for substantial waste heat recovery. However, a major challenge is the absence of benchmark data on high-performance computing (HPC) heat generation and waste heat profiles. This paper reports power demand and waste heat measurements from an ORNL HPC data centre, aiming to guide future research on optimizing waste heat recovery in large-scale data centres, especially those of HPC calibre.

Reappraisal of lymphatic mapping for midgut neuroendocrine patients undergoing cytoreductive surgery.

BACKGROUND: We previously reported that midgut neuroendocrine tumors (NETs) often develop alternative lymphatic drainage owing to lymphatic obstructions from extensive mesenteric lymphadenopathy, making intraoperative lymphatic mapping mandatory. We hypothesize that this innovative approach needs a longer term validation. METHODS: We updated our results by reviewing 303 patients who underwent cytoreduction from November 2006 to October 2011. Of these patients, 112 had lymphatic mappings and 98 were for midgut NET primaries. Among them, 77 mappings were for the initial cytoreduction and 35 were for reexploration and further cytoreduction. The operative findings, pathology reports, and long-term surgical outcomes were reviewed. RESULTS: Lymphatic mapping changed traditional resection margins in 92% of patients. Of the 35 patients who underwent reexploration without initial mapping, 19 (54%) showed a recurrence at or near the anastomotic sites. In contrast, none of the 112 mapped patients had shown signs of recurrence in a 1- to 5-year follow-up. Additionally, 20 of 45 ileocecal valves (44.4%) were spared in patients whose tumors were at the terminal ileum that, traditionally, would call for a right hemicolectomy. CONCLUSION: With a longer follow-up, lymphatic mapping has proven to be a safe and effective way to prevent local recurrences and preserve the ileocecal valve for selected patients.

Full-field imaging-based instantaneous hyperspectral absolute refractive index measurement.

Multispectral refractometers typically measure refractive index (RI) at discrete monochromatic wavelengths via a serial process. We report on the demonstration of a white light full-field imaging-based refractometer capable of instantaneous multispectral measurement of absolute RI of clear liquid-gel samples across the entire visible light spectrum. The broad optical bandwidth refractometer is capable of hyperspectral measurement of RI in the range 1.30-1.70 between 400 and 700 nm with a maximum error of 0.0036 units (0.24% of actual) at 414 nm for an η=1.50 sample. We present system design and calibration method details as well as results from a system validation sample.

Wavelength, temperature, and voltage dependent calibration of a nematic liquid crystal multispectral polarization generating device.

Rapid calibration of liquid crystal variable retarder (LCVR) devices is critical for successful clinical implementation of a LC-based Mueller matrix imaging system being developed for noninvasisve skin cancer detection. For multispectral implementation of such a system, the effect of wavelength (lambda), temperature (T), and voltage (V) on the retardance (delta) required to generate each desired polarization state needs to be clearly understood. Calibration involves quantifying this interdependence such that for a given set of system input variables (lambda,T), the appropriate voltage is applied across a LC cell to generate a particular retardance. This paper presents findings that elucidate the dependence of voltage, for a set retardance, on the aforementioned variables for a nematic LC cell: approximately 253 mV/100 nm lambda-dependence and approximately 10 mV/ degrees CT-dependence. Additionally, an empirically derived model is presented that enables initial voltage calibration of retardance for any desired input wavelength within the calibration range of 460-905 nm.