Abstract
Cost efficiency and defect passivation are the two major challenges that thin-film solar cells have to overcome for economic competitiveness. For Cu(In,Ga)Se
2
solar cells, the first is ...addressed by an increase of the Ga/In ratio, which widens the bandgap favorably for tandem applications and reduces the requirement of costly, rare In. The second is addressed by heavy alkali post-deposition treatments. However, the maximum device efficiency is typically achieved with a comparably low Ga/In ratio, which is in contrast to the economic interest of a higher Ga/In ratio and makes it paramount to identify, understand and mitigate the sources of local underperformance in Ga-rich cells. In this work, we investigate a series of Cu(In,Ga)Se
2
cells with varying Ga/In concentration in the absorber, using multi-modal scanning x-ray microscopy. In particular, we analyze differences in chemical composition and electrical performance on the nanoscale, with a focus on the effect of Rb. We find that In-rich cells show, along with a greater overall performance, a more homogeneous distribution of the nanoscale performance compared to the Ga-rich cells. Our analysis on Rb suggests that this effect is due to a more effective passivation of structural defects in the absorbers, i.e. voids and grain boundaries. These results shine light on the causes of the superiority of Ga-poor/In-rich absorbers and substantiate the trend to higher defect density for Ga-rich absorbers.
This paper reports results of exposure experiments with martensitic steel T91 for 1200, 2998 and 5016
h in the CORRIDA loop. Owing to initial problems with the enrichment of oxygen in the circulating ...LBE, the conditions with respect to the oxygen activity (expressed as the activity of lead oxide,
a
PbO) varied significantly. At 550
°C, oxidation is the only mode of material degradation for T91 in flowing LBE (2
m/s) when the oxygen activity corresponds to 10
−4
⩽
a
PbO
⩽
10
−2. The mean oxidation rate in the course of the first 1200
h approximates 0.13
mm/year. Lower oxygen activity in the LBE (10
−6
⩽
a
PbO
⩽
10
−4) may be beneficial with respect to the oxidation rate, but undershooting a certain value around the threshold for Fe
3O
4 stability (
a
PbO
=
10
−5.2) poses the risk of liquid–metal attack accompanied by high local material consumption. The composition and structure of the oxide scales on the surface of T91 are analysed and a mechanism for scale growth initiating from oxide nuclei of various compositions is proposed.
Center for Medicare and Medicaid Services reimbursement is the same for hip arthroplasty performed electively for arthritis and urgently for femoral neck fracture.
An analytic report of hip ...arthroplasty for a 5-hospital network identified 2362 cases performed from January 2014 to May 2016. Resource utilization was determined using 90-day charges.
The fracture population (623 hips) was older (P < .01), had more medical comorbidities (28.3% vs 3.8%, P < .01), and was more likely to be anemic and malnourished (P < .01), and had longer hospital stay (5.7 vs 3.0 days, P < .0001), more frequent intensive care unit admission (4.5% vs 0.5%, P < .01), less frequent discharge to home (16.2% vs 83.6%, P < .01), more emergency department visits (26.5% vs 10.7%, P < .01), and more readmissions after hospital discharge (25.2% vs 12.2%, P < .01). Utilization of services ($50,875 vs $38,705, P < .0001) and the standard deviation of these services ($22,509 vs $9,847, P < .0001), from 90-day charges, were significantly greater in the fracture population.
This study supports exclusion of fracture care from the Comprehensive Care for Joint Replacement bundled payment program.
Mini-Subvastus Approach for Total Knee Arthroplasty Schroer, William C., MD; Diesfeld, Paul J., PA-C; Reedy, Mary E., RN ...
The Journal of arthroplasty,
2008, January 2008, 2008-Jan, 2008-01-00, 20080101, Letnik:
23, Številka:
1
Journal Article
Recenzirano
Abstract The mini-subvastus surgical technique avoids both quadriceps arthrotomy and patella eversion. Since March 2003, this quad-sparing minimally invasive surgical (MIS) technique has been applied ...to more than 98% of our primary total knee arthroplasty (TKA) patients. This study compares our first 150 MIS TKA patients to our previous 150 traditional TKA patients. Quadriceps recovery was rapid in the MIS group with 83% able to do a straight leg raise the day after surgery. Hospital length of stay was decreased in the MIS group, 3.4 days, vs the traditional group, 4.1 days ( P = .00013). Fewer MIS patients required skilled nursing or rehabilitation center admission. Increased knee flexion was seen for the MIS patients throughout the first 2 years of follow-up. Mean knee flexion at 1 year was 127° for the MIS patients vs 114° in the traditional TKA patients ( P < .0001). Comparison between the MIS and traditional techniques demonstrated no increase in the number or severity of complications and no difference in operating room time.
The generation of electricity is one of the great challenges of our time, and its success shall be measured by the sustainability from ecological, economical, and social points of view. The advent of ...photovoltaics has led to a dramatic decrease of the levelized cost of energy (LCOE) such that it has not only reached grid parity in many countries but is often the most competitive energy source.
Multilayer laue lenses are diffractive optics with a high potential for producing X-ray foci in the order of 10 nm or even below. Particularly for hard X-rays (E > 6 keV) these optics promise better ...resolution and higher efficiencies than currently available Fresnel zone plates. Magnetron sputter deposition has been used for the fabrication of multilayer laue lenses using the layer materials MoSi2 and Si. The lens design has been defined to get focal length in the order of 10 mm. One of the lenses with an aperture of about 20 μm has been used as focusing optics in the nanoprobe beamline P06 at PETRA III. Ptychography has been applied to characterize the caustic of the focused beam and to determine the size of the X-ray focus. A spot size of about 39 nm could be obtained with a photon energy of 21 keV and a focal length of 9.9 mm.
The opioid crisis has illuminated the risks of opioid use for pain management, with renewed interest in reducing opioid consumption after common orthopedic procedures. Anti-inflammatory medication is ...an important component of multimodal pain management for patients undergoing orthopedic surgery. The purpose of this study was to evaluate the effect of celecoxib on pain control and opioid use after shoulder surgery.
Patients scheduled for either total shoulder replacement (group 1) or rotator cuff repair (group 2) were candidates for the study. The exclusion criteria included allergy to celecoxib, coagulopathy, use of anticoagulants, baseline use of long-acting opioids, and a history of medical conditions such as myocardial infarction or stroke. Consenting patients were randomized by type of procedure using block randomization to receive either placebo or celecoxib 1 hour prior to the procedure and for 3 weeks postoperatively. The primary outcome measure assessed was opioid utilization as measured by morphine-equivalent dose (MED). Secondary outcome measures included pain scores at 3 and 6 weeks postoperatively. Data were analyzed using multiple linear regression.
Of 1081 patients scheduled for either total shoulder replacement or rotator cuff repair from February 2014 to February 2018, 78 were enrolled for arthroplasty (group 1, with 39 receiving celecoxib and 39 receiving placebo) and 79 were enrolled for rotator cuff repair (group 2, with 40 receiving celecoxib and 39 receiving placebo). Compared with the placebo arm, patients prescribed celecoxib took fewer MEDs by –168 (95% confidence interval CI, –272 to –64; P < .01) at 3 weeks in the total population and by –197.7 (95% CI, –358 to –38; P = .02) in the arthroplasty group. Similarly, at 6 weeks, total MEDs used was –199 (95% CI, –356 to –42; P < .01) in the total population and –270 (95% CI, –524 to –16; P = .04) in the arthroplasty group. No statistically significant differences in opioid consumption were found between study arms in the cuff repair group, at either 3 or 6 weeks. Of note, preoperative opioid use was statistically associated with higher levels of opioid use in the total population and group 1 at 3 and 6 weeks (P < .01 for all) but not in group 2 (P > .05 for both).
Use of morphine equivalents was statistically significantly less at 3 and 6 weeks in patients who took celecoxib in the total population and in the arthroplasty group. Patients prescribed celecoxib for 3 weeks after shoulder surgery took less opioid medication for pain at 3 and 6 weeks. Multimodal pain control using celecoxib is an effective way to reduce postoperative opioid use in shoulder arthroplasty patients. Preoperative opioid use is associated with higher levels of opioid use after shoulder arthroplasty.
Abstract
Liquid metals have been used in various applications in nuclear systems. Lead-bismuth eutectic (LBE) is foreseen as a coolant and target for neutron generation in accelerator-driven systems ...(ADS), whereas pure lead will be used as coolant in Gen IV-type lead-cooled fast reactors (LFR). The advantage of heavy liquid metal alloys is their high thermal conductivity and their relative safety in case of an accident. A major problem in non-isothermal systems is the corrosion of their structural components, consisting mainly of ferritic/martensitic and austenitic stainless steels, since the solubility of dissolved elements depends strongly on temperature. The formation of oxide scales on structural components is considered a viable approach to limiting the corrosion rates. To maintain a specific oxygen content in lead or LBE, an oxygen control system (OCS) is crucial. This requires continuous measurement of the oxygen activity in the liquid metal by means of electrochemical sensors. It must be assured that no oxides of the liquid metal itself are formed; otherwise, the system can be blocked. Therefore, this paper addresses the development of oxygen sensors for corrosion control of martensitic and austenitic steels in a lead-bismuth eutectic system at Forschungszentrum Karlsruhe (FZK, Eggenstein-Leopoldshafen, Germany).
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