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2021 ◽  
Vol 242 (1) ◽  
Author(s):  
K. Szymański ◽  
W. Olszewski ◽  
P. Butkiewicz ◽  
M. Biernacka ◽  
D. Satuła ◽  
...  

AbstractMössbauer measurements on single crystal absorbers at room and at low temperatures were performed. The results are fully consistent with previously published reports by other groups. Spectra of single crystals were simultaneously analyzed including magnetic dipole and electric quadrupole interactions. The analysis shows that there is a small component of magnetic moments perpendicular to the magnetic easy axis. Mössbauer data seem not agree with commonly accepted ferrimagnetic structure of GaFeO3.


2021 ◽  
pp. 1-10
Author(s):  
Thibaud Denneulin ◽  
Jan Caron ◽  
Knut Müller-Caspary ◽  
Olivier Boulle ◽  
András Kovács ◽  
...  

Multilayers that comprise thin films of heavy metals and ferromagnets have been shown to host Néel-type magnetic skyrmions at room temperature. Fresnel defocus imaging in Lorentz transmission electron microscopy is a widely used technique for recording magnetic information about skyrmions. However, the visibility of Néel-type skyrmions in Fresnel defocus images is typically low, both because only a small component of their magnetic field contributes to the signal and because of the presence of diffraction contrast from the polycrystalline multilayer structure. Here, we take advantage of the out-of-plane hysteresis in such samples to record background-subtracted Fresnel defocus images. We demonstrate an improvement in magnetic signal-to-noise ratio and spatial resolution by a factor of 3 for a (Pt/Co/NiFe)×5 multilayer. We also use simulated Fresnel defocus images of Néel-type magnetic skyrmions to understand the influence of defocus on apparent skyrmion size.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5908
Author(s):  
Alexandra Adiaconitei ◽  
Ionut Sebastian Vintila ◽  
Radu Mihalache ◽  
Alexandru Paraschiv ◽  
Tiberius Florian Frigioescu ◽  
...  

In the space industry, the market demand for high-pressure mechanically pumped fluid loop (MPFL) systems has increased the interest for integrating advanced technologies in the manufacturing process of critical components with complex geometries. The conventional manufacturing process of a closed impeller encounters different technical challenges, but using additive manufacturing (AM) technology, the small component is printed, fulfilling the quality requirements. This paper presents the Laser Powder Bed Fusion (LPBF) process of a closed impeller designed for a centrifugal pump integrated in an MPFL system with the objective of defining a complete manufacturing process. A set of three closed impellers was manufactured, and each closed impeller was subjected to dimensional accuracy analysis, before and after applying an iterative finishing process for the internal surface area. One of the impellers was validated through non-destructive testing (NDT) activities, and finally, a preliminary balancing was performed for the G2.5 class. The process setup (building orientation and support structure) defined in the current study for a pre-existing geometry of the closed impeller takes full advantages of LPBF technology and represents an important step in the development of complex structural components, increasing the technological readiness level of the AM process for space applications.


Author(s):  
Maksymilian Gajda ◽  
Małgorzata Kowalska ◽  
Jan Eugeniusz Zejda

The proper recruitment of subjects for population-based epidemiological studies is critical to the external validity of the studies and, above all, to the sound and correct interpretation of the findings. Since 2020, the novel coronavirus SARS-CoV-2 pandemic has been a new factor that has been, additionally, hindering studies. Therefore, the aim of our study is to compare demographic, socio-economic, health-related characteristics and the frequency of SARS-CoV-2 infection occurrence among the randomly selected group and the group composed of volunteers. We compare two groups of participants from the cross-sectional study assessing the seroprevalence of SARS-CoV-2 coronavirus, which was conducted in autumn 2020, in three cities of the Silesian Voivodeship in Poland. The first group consisted of a randomly selected, nationally representative, age-stratified sample of subjects (1167 participants, “RG” group) and was recruited using personal invitation letters and postal addresses obtained from a national registry. The second group (4321 volunteers, “VG” group) included those who expressed their willingness to participate in response to an advertisement published in the media. Compared with RG subjects, volunteers were more often females, younger and professionally active, more often had a history of contact with a COVID-19 patient, post-contact nasopharyngeal swab, fewer comorbidities, as well as declared the occurrence of symptoms that might suggest infection with SARS-CoV-2. Additionally, in the VG group the percentage of positive IgG results and tuberculosis vaccination were higher. The findings of the study confirm that surveys limited to volunteers are biased. The presence of the bias may seriously affect and distort inference and make the generalizability of the results more than questionable. Although effective control over selection bias in surveys, including volunteers, is virtually impossible, its impact on the survey results is impossible to predict. However, whenever possible, such surveys could include a small component of a random sample to assess the presence and potential effects of selection bias.


Indian culture is based on Dharma which is known as Sanatan Dharma or Universal Religion. As per the principles of Sanatan Dharma, the individual soul itself is the Supreme soul. One small component of the Parmatma or the Supreme soul is present in all beings in the form of the Jivatma. Out of the 84 lakh species that are believed to exist in this world, the human species is considered to be of paramount importance as the ultimate self can be realised only through the means of the human body by the performance of YógSadhana. Indian sages have shown the path of Yógin order to attain this aim of realising the Paramatma. Four typesof Yóg have been mentioned in the scriptures and Mantra Yóg is considered to be the gateway to Yóg.


Author(s):  
I. L. Rogovskii ◽  

Based on the analysis of most domestic combines, it is established that they have a traditional scheme of threshing and separating device, which includes one or two sequentially arranged threshing threshers and keyboard straw shaker. The design of drumming from rods with cross plates provides, first of all, intensification of process of threshed grain. Cereals are threshed easily, so there is no need to intensify threshing. For example, when harvesting grain harvester KZS-9M "Slavutich" with a gap at the outlet between the threshing drum and the drum 18 mm and the speed of the threshing drum 450 min-1, the loss of threshing was absent in all experiments. In this case, the transverse plates of the drum are an obstacle to the movement of the threshed mass in the threshing-separating device, forming a dead space behind each bar, where a small component of plant mass accumulates. The quality of the threshing and separating device of the combine harvester was determined by the coefficients of undersmilling, separation, crushing and clogging of the grain received for cleaning. Damage to the grain during threshing in the thresher is mainly due to the influence of the circumferential linear velocity of the threshing drum and the gap between the threshing drum and the drum. Therefore, the gap in the threshing space is variable and changes in the direction of decrease from the entrance of the plant mass into the threshing device to its exit. To summarize, we used the gap in the threshing space at the outlet of the thresher. In this regard, the beginning of the tests was at a drum speed of 450 min-1. During the tests it was found that the greatest influence on the damage to the grain has a circular linear speed of the threshing drum. Thus, when increasing the speed of the drum per 100 min-1 from 450 to 550 min-1, the damage increased from 1.5% to 5.5%, ie almost 4 times.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
George Sgouros ◽  
Bin He ◽  
Nitya Ray ◽  
Dale L. Ludwig ◽  
Eric C. Frey

Abstract Background Actinium-225 is an alpha-particle emitter under investigation for use in radiopharmaceutical therapy. To address limited supply, accelerator-produced 225Ac has been recently made available. Accelerator-produced 225Ac via 232Th irradiation (denoted 225/7Ac) contains a low percentage (0.1–0.3%) of 227Ac (21.77-year half-life) activity at end of bombardment. Using pharmacokinetic modeling, we have examined the dosimetric impact of 227Ac on the use of accelerator-produced 225Ac for radiopharmaceutical therapy. We examine the contribution of 227Ac and its daughters to tissue absorbed doses. The dosimetric analysis was performed for antibody-conjugated 225/7Ac administered intravenously to treat patients with hematological cancers. Published pharmacokinetic models are used to obtain the distribution of 225/7Ac-labeled antibody and also the distribution of either free or antibody-conjugated 227Th. Results Based on our modeling, the tissue specific absorbed dose from 227Ac would be negligible in the context of therapy, less than 0.02 mGy/MBq for the top 6 highest absorbed tissues and less than 0.007 mGy/MBq for all other tissues. Compared to that from 225Ac, the absorbed dose from 227Ac makes up a very small component (less than 0.04%) of the total absorbed dose delivered to the 6 highest dose tissues: red marrow, spleen, endosteal cells, liver, lungs and kidneys when accelerator produced 225/7Ac-conjugated anti-CD33 antibody is used to treat leukemia patients. For all tissues, the dominant contributor to the absorbed dose arising from the 227Ac is 227Th, the first daughter of 227Ac which has the potential to deliver absorbed dose both while it is antibody-bound and while it is free. CONCLUSIONS: These results suggest that the absorbed dose arising from 227Ac to normal organs would be negligible for an 225/7Ac-labeled antibody that targets hematological cancer.


Water SA ◽  
2021 ◽  
Vol 47 (3 July) ◽  
Author(s):  
Michael van der Laan ◽  
Sandra Eckert ◽  
Maya da Silva ◽  
John Annandale

Due to population growth and agricultural intensification, water scarcity is increasing in the Upper Ewaso Ng’iro Basin. Quantitative information is needed to improve the management of this resource, but is a challenge due to lack of hydrometeorological data. Using water footprint thinking, a pragmatic approach applying available information and simple assumptions was used to estimate blue and green water availability and consumption for different land uses and activities. Despite the attention it receives, flower production makes up a small component of the basin’s water footprint (1.4% of blue water consumed, roses used 0.73%), although the drastic impact of horticulture on low flows during dry periods is recognized. Surface water evaporation from irrigation dams containing captured floodwaters or pumped groundwater has a water footprint comparable to greenhouse horticultural production itself. Small-scale irrigation was estimated to use 71.4% of the blue water consumed, while total commercial horticultural production was estimated to use 8.2%. Direct human consumption was estimated at 3% and livestock and wildlife consumption at 4.2% of consumed blue water. Labour opportunities were almost 10 times higher for roses than for maize per hectare and per m3 of water consumed. Water productivity in terms of selling price was 128 times higher for 1 tonne of roses than for 1 tonne of maize. This approach can be used in data-poor regions to advance understanding between multiple stakeholders (such as between farmers, pastoralists and conservationists) for participatory management, and to better understand the basin’s water balance to estimate exploitable water resources.


2021 ◽  
Vol 103-B (7 Supple B) ◽  
pp. 25-32 ◽  
Author(s):  
Harlan C. Amstutz ◽  
Michel Jean Le Duff

Aims Adverse local tissue reactions associated with abnormal wear considerably slowed down the general use of metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), now limited to a few specialized centres. In this study, we provide the clinical results of 400 consecutive MoM HRAs implanted more than 20 years ago in one such centre. Methods A total of 355 patients (400 hips) were treated with Conserve Plus HRA between November 1996 and November 2000. There were 96 female (27%) and 259 male patients (73%). Their mean age was 48.2 years (SD 10.9). The University of California, Los Angeles (UCLA) hip scores and 12-item Short Form Survey (SF-12) quality of life scores were reported. Survivorship was assessed using Kaplan-Meier analyses. Results The mean follow-up was 16.5 years (0.1 to 24.0), including 34 patients (37 hips) who died. The mean UCLA hip scores were 9.3 (2 to 10), 9.1 (3 to 10), 9.0 (3 to 10), and 6.9 (2 to 10) for pain, walking, function, and activity, respectively. The mean SF-12 scores were 48.4 (16.0 to 62.1) for the physical component and 48.5 (10.5 to 66.5) for the mental component, and did not differ from those of the general population of the USA. A total of 60 hips in 55 patients were revised. Using revision for any indication as the endpoint, the Kaplan-Meier survivorship was 83.5% at 20 years. A diagnosis of developmental dysplasia (hazard ratio (HR) 2.199 (95% confidence interval (CI) 1.140 to 4.239); p = 0.019) and a low BMI (HR 0.931 (95% CI 0.873 to 0.994); p = 0.032) were risk factors for revision. Female sex was a risk factor only because of hip dysplasia and small component size. There were no cases of metal sensitivity associated with revision surgery. Radiological analysis showed persistent fixation in all but one hip. Conclusion The 83.5% 20-year survivorship of this initial series surpasses that of total hip arthroplasties in use 20 years ago in these young patients, suggesting satisfactory lifelong durability of the device for almost all of the remaining patients. Cite this article: Bone Joint J 2021;103-B(7 Supple B):25–32.


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