15 research outputs found
Hole burning in a nanomechanical resonator coupled to a Cooper pair box
We propose a scheme to create holes in the statistical distribution of
excitations of a nanomechanical resonator. It employs a controllable coupling
between this system and a Cooper pair box. The success probability and the
fidelity are calculated and compared with those obtained in the atom-field
system via distinct schemes. As an application we show how to use the
hole-burning scheme to prepare (low excited) Fock states.Comment: 7 pages, 10 figure
The hypertension cascade of care in the midst of conflict: the case of the Gaza Strip
Although hypertension constitutes a substantial burden in conflict-affected areas, little is known about its prevalence, control, and management in Gaza. This study aims to estimate the prevalence and correlates of hypertension, its diagnosis and control among adults in Gaza. We conducted a representative, cross-sectional, anonymous, household survey of 4576 persons older than 40 years in Gaza in mid-2020. Data were collected through face-to-face interviews, anthropometric, and blood pressure measurements. Hypertension was defined in anyone with an average systolic blood pressure â„140âmmHg or average diastolic blood pressure â„90âmmHg from two consecutive readings or a hypertension diagnosis. The mean age of participants was 56.9â±â10.5 years, 54.0% were female and 68.5% were Palestinian refugees. The prevalence of hypertension was 56.5%, of whom 71.5% had been diagnosed. Hypertension was significantly higher among older participants, refugees, ex-smokers, those who were overweight or obese, and had other co-morbidities including mental illnesses. Two-thirds (68.3%) of those with hypertension were on treatment with one in three (35.6%) having their hypertension controlled. Having controlled hypertension was significantly higher in females, those receiving all medications for high blood pressure and those who never or rarely added salt to food. Investing in comprehensive but cost-effective initiatives that strengthen the prevention, early detection and timely treatment of hypertension in conflict settings is critical. It is essential to better understand the underlying barriers behind the lack of control and develop multi-sectoral programs to address these barriers
Refinery Energy Conservation Experience with Enhanced Surface Reboilers
Examples of refinery services where existing reboilers were retubed or replaced with enhanced High Flux tubing to better utilize or conserve energy are reported.
(1) Retubing an existing toluene column reboiler permitted the use of low cost 115 psig s team rather than 400 psig. An annual steam cost saving of 719, 000 with less than one month payback.
(3) A large existing propane-propylene splitter underwent a major conversion to reduce energy consumption. By replacing the existing reboilers with High Flux and converting the system to a vapor recompression cycle over $2,000, 000 in annual steam cost savings were realized
High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns
Vapor recompression of distillation columns overheads, followed by subsequent condensation in the reboiler results in substantial operating cost savings compared to conventional steam driven reboiler systems. The use of high performance heat exchangers and distillation trays permits additional energy savings by lower reboiler temperature differences, and reduced reflux requirements for a fixed column height, due to closer tray spacings.
This paper surveys the heat pump systems currently in operation using high performance UCC MD trays and High Flux tubing. Design considerations for high or low pressure level towers, with single or dual stage compression equipment are discussed, along with the various control methods. Factors affecting startup, part load, and off design operation of the equipment are also reviewed