ABSTRACT
Advances in imaging have made it possible to view nanometer and sub-nanometer structures that are either synthesized or that occur naturally. It is believed that fluid dynamic and thermodynamic behavior differ significantly at these scales from the bulk. From a materials perspective, it is important to be able to create complex structures at the nanometer scale, reproducibly, so that the fluid behavior may be studied. New advances in nanoscale-resolution 3D-printing offer opportunities to achieve this goal. In particular, additive manufacturing with two-photon polymerization allows creation of intricate structures. Using this technology, a creation of the first nano-3D-printed digital (shale) rock is reported. In this paper, focused ion beam-scanning electron microscopy (FIB-SEM) nano-tomography image dataset was used to reconstruct a high-resolution digital rock 3D model of a Marcellus Shale rock sample. Porosity of this 3D model has been characterized and its connected/effective pore system has been extracted and nano-3D-printed. The workflow of creating this novel nano-3D-printed digital rock 3D model is described in this paper.
ABSTRACT
OBJECTIVE: To examine the results of a quality-improvement study that implemented an enhanced recovery after surgery (ERAS) program for cesarean delivery. METHODS: A pre-post design was used to assess changes in opioid use, length of stay, and costs among all patients undergoing cesarean delivery before and after implementation of an evidence-based ERAS pathway for the preoperative, intraoperative, and postoperative management of patients beginning December 2018. RESULTS: A total of 3,679 cesarean deliveries (scheduled and emergent) were included from January 1, 2018, through August 31, 2019, of which 2,171 occurred before implementation on December 17, 2018, and 1,508 occurred postimplementation. Eighty-four percent of patients received opioids as inpatients after cesarean delivery during the preimplementation period, as compared with 24% in the postimplementation period (odds ratio [OR] 16.8, 95% CI 14.3-19.9). Among patients who required any opioids, the total morphine milligram equivalents also significantly decreased (median 56.5 vs 15.0, mean relative change 0.32, 95% CI 0.28-0.35). Compared with the preimplementation period, those in the postimplementation period had a shorter postcesarean length of stay (3.2 vs 2.7 days, mean relative change 0.82, 95% CI 0.80-0.83, median 3 days in both periods), lower median direct costs by $349 (mean relative change 0.93, 95% CI 0.91-0.95), and no change in the 30-day readmission rate (1.4% vs 1.7%, OR 0.83, 95% CI 0.49-1.41). CONCLUSION: An ERAS approach for the cesarean delivery population is associated with improved outcomes including decreases in opioid use, length of stay, and costs.
Subject(s)
Analgesics, Opioid/therapeutic use , Cesarean Section , Enhanced Recovery After Surgery , Pain, Postoperative/therapy , Postoperative Care , Adult , Analgesics/therapeutic use , Cesarean Section/adverse effects , Cesarean Section/methods , Costs and Cost Analysis , Female , Humans , Length of Stay/statistics & numerical data , Outcome Assessment, Health Care , Patient Readmission/statistics & numerical data , Postoperative Care/economics , Postoperative Care/methods , Postoperative Care/standards , Pregnancy , Quality ImprovementABSTRACT
Porosity and permeability are the key factors in assessing the hydrocarbon productivity of unconventional (shale) reservoirs, which are complex in nature due to their heterogeneous mineralogy and poorly connected nano- and micro-pore systems. Experimental efforts to measure these petrophysical properties posse many limitations, because they often take weeks to complete and are difficult to reproduce. Alternatively, numerical simulations can be conducted in digital rock 3D models reconstructed from image datasets acquired via e.g., nanoscale-resolution focused ion beam-scanning electron microscopy (FIB-SEM) nano-tomography. In this study, impact of reservoir confinement (stress) on porosity and permeability of shales was investigated using two digital rock 3D models, which represented nanoporous organic/mineral microstructure of the Marcellus Shale. Five stress scenarios were simulated for different depths (2,000-6,000 feet) within the production interval of a typical oil/gas reservoir within the Marcellus Shale play. Porosity and permeability of the pre- and post-compression digital rock 3D models were calculated and compared. A minimal effect of stress on porosity and permeability was observed in both 3D models. These results have direct implications in determining the oil-/gas-in-place and assessing the production potential of a shale reservoir under various stress conditions.
