The Unsolved Problem of Ball Lightning

Nature ◽  
1963 ◽  
Vol 198 (4882) ◽  
pp. 745-747 ◽  
Author(s):  
STANLEY SINGER
Keyword(s):  
Unsolved Problem ◽  
Ball Lightning

scholarly journals A brief history of ball lightning observations by scientists and trained professionals

2021 ◽  
Vol 12 (1) ◽  
pp. 43-56
Author(s):  
Alexander G. Keul
Keyword(s):  
Unsolved Problem ◽  
Ball Lightning ◽  
Case Histories ◽  
Abstract Form ◽  
Transient Phenomenon ◽  
Atmospheric Physics ◽  
Eyewitness Reports ◽  
History Of ◽  
Trained Observers ◽  
Instrumental Records

Abstract. With thousands of eyewitness reports, but few instrumental records and no consensus about a theory, ball lightning remains an unsolved problem in atmospheric physics. As chances to monitor this transient phenomenon are low, it seems promising to evaluate observation reports by scientists and trained professionals. The following work compiles 20 published case histories and adds 15 from the author's work and 6 from a Russian database. Forty-one cases from eight countries, 1868–2020, are presented in abstract form with a synthesis. The collection of cases does not claim to be complete. Six influential or notable ball lightning cases are added. It is concluded that well-documented cases from trained observers can promote fieldwork and stimulate and evaluate ball lightning theories. Scientists who have not reported their experience are invited to share it with the author.

BALL LIGHTNING: THE UNSOLVED PROBLEM

Weather ◽  
1982 ◽  
Vol 37 (3) ◽  
pp. 66-75 ◽  
Author(s):  
W. N. Charman
Keyword(s):  
Unsolved Problem ◽  
Ball Lightning

Current problems in ball lightning science

1990 ◽  
Vol 160 (4) ◽  
pp. 95 ◽  
Author(s):  
Boris M. Smirnov
Keyword(s):  
Ball Lightning

scholarly journals Towards a Methodology for Component Design of Metallic AM Parts Subjected to Cyclic Loading

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 709
Author(s):  
Uwe Zerbst ◽  
Mauro Madia ◽  
Giovanni Bruno ◽  
Kai Hilgenberg
Keyword(s):  
Unsolved Problem ◽  
Fatigue Cracks ◽  
Special Focus ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Lack Of Fusion ◽  
Fatigue Design ◽  
Component Design ◽  
Similar Temperature ◽  
Potential Improvement

The safe fatigue design of metallic components fabricated by additive manufacturing (AM) is still a largely unsolved problem. This is primarily due to (a) a significant inhomogeneity of the material properties across the component; (b) defects such as porosity and lack of fusion as well as pronounced surface roughness of the as-built components; and (c) residual stresses, which are very often present in the as-built parts and need to be removed by post-fabrication treatments. Such morphological and microstructural features are very different than in conventionally manufactured parts and play a much bigger role in determining the fatigue life. The above problems require specific solutions with respect to the identification of the critical (failure) sites in AM fabricated components. Moreover, the generation of representative test specimens characterized by similar temperature cycles needs to be guaranteed if one wants to reproducibly identify the critical sites and establish fatigue assessment methods taking into account the effect of defects on crack initiation and early propagation. The latter requires fracture mechanics-based approaches which, unlike common methodologies, cover the specific characteristics of so-called short fatigue cracks. This paper provides a discussion of all these aspects with special focus on components manufactured by laser powder bed fusion (L-PBF). It shows how to adapt existing solutions, identifies fields where there are still gaps, and discusses proposals for potential improvement of the damage tolerance design of L-PBF components.

scholarly journals Morikawa’s Unsolved Problem

2021 ◽  
Vol 128 (3) ◽  
pp. 214-237
Author(s):  
Jan E. Holly ◽  
David Krumm
Keyword(s):  
Unsolved Problem

scholarly journals General synthetic strategy for regioselective ultrafast formation of disulfide bonds in peptides and proteins

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shay Laps ◽  
Fatima Atamleh ◽  
Guy Kamnesky ◽  
Hao Sun ◽  
Ashraf Brik
Keyword(s):  
Drug Discovery ◽  
Disulfide Bonds ◽  
Unsolved Problem ◽  
De Novo ◽  
Therapeutic Potential ◽  
Selective Activation ◽  
One Pot ◽  
Synthetic Strategy ◽  
The One ◽  
Game Changer

AbstractDespite six decades of efforts to synthesize peptides and proteins bearing multiple disulfide bonds, this synthetic challenge remains an unsolved problem in most targets (e.g., knotted mini proteins). Here we show a de novo general synthetic strategy for the ultrafast, high-yielding formation of two and three disulfide bonds in peptides and proteins. We develop an approach based on the combination of a small molecule, ultraviolet-light, and palladium for chemo- and regio-selective activation of cysteine, which enables the one-pot formation of multiple disulfide bonds in various peptides and proteins. We prepare bioactive targets of high therapeutic potential, including conotoxin, RANTES, EETI-II, and plectasin peptides and the linaclotide drug. We anticipate that this strategy will be a game-changer in preparing millions of inaccessible targets for drug discovery.

scholarly journals Effects of state-wide implementation of the Los Angeles Motor Scale for triage of stroke patients in clinical practice

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Stefanie Behnke ◽  
Thomas Schlechtriemen ◽  
Andreas Binder ◽  
Monika Bachhuber ◽  
Mark Becker ◽  
...  
Keyword(s):  
Los Angeles ◽  
Acute Stroke ◽  
Unsolved Problem ◽  
Standard Operating Procedure ◽  
Stroke Management ◽  
Stroke Patients ◽  
Vessel Occlusion ◽  
Standard Operating ◽  
Los Angeles Motor Scale ◽  
Triage Decisions

Abstract Background The prehospital identification of stroke patients with large-vessel occlusion (LVO), that should be immediately transported to a thrombectomy capable centre is an unsolved problem. Our aim was to determine whether implementation of a state-wide standard operating procedure (SOP) using the Los Angeles Motor Scale (LAMS) is feasible and enables correct triage of stroke patients to hospitals offering (comprehensive stroke centres, CSCs) or not offering (primary stroke centres, PSCs) thrombectomy. Methods Prospective study involving all patients with suspected acute stroke treated in a 4-month period in a state-wide network of all stroke-treating hospitals (eight PSCs and two CSCs). Primary endpoint was accuracy of the triage SOP in correctly transferring patients to CSCs or PSCs. Additional endpoints included the number of secondary transfers, the accuracy of the LAMS for detection of LVO, apart from stroke management metrics. Results In 1123 patients, use of a triage SOP based on the LAMS allowed triage decisions according to LVO status with a sensitivity of 69.2% (95% confidence interval (95%-CI): 59.0–79.5%) and a specificity of 84.9% (95%-CI: 82.6–87.3%). This was more favourable than the conventional approach of transferring every patient to the nearest stroke-treating hospital, as determined by geocoding for each patient (sensitivity, 17.9% (95%-CI: 9.4–26.5%); specificity, 100% (95%-CI: 100–100%)). Secondary transfers were required for 14 of the 78 (17.9%) LVO patients. Regarding the score itself, LAMS detected LVO with a sensitivity of 67.5% (95%-CI: 57.1–78.0%) and a specificity of 83.5% (95%-CI: 81.0–86.0%). Conclusions State-wide implementation of a triage SOP requesting use of the LAMS tool is feasible and improves triage decision-making in acute stroke regarding the most appropriate target hospital.

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