bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of heat treatments on friction stir processed aluminium surface composites
Authors: Girish G. , Anandakrishnan V. 
Published: February 2022

In this study, an age-hardenable Al–Zn–Mg–Cu alloy was reinforced with titanium carbide particles by a novel method and a surface composite synthesised by way of recursive friction stir processing (FSP). The effects of age hardening (T6) and retrogression and reaging (RRA) treatments on microstructural evolution, and mechanical properties were investigated. Compared to the base material, significant grain refinement and improved mechanical properties were noticed in the friction stir processed Al/TiC composite due to the homogenous distribution of reinforcement. During heat treatments, the presence of reinforcement inhibited the growth of grains during dynamic recrystallisation producing a microstructure with finer grains. The heat-treated composites exhibited better mechanical properties than as-fabricated composite due to combined effect of reinforcement and the precipitated phases. GRAPHICAL ABSTRACT
Generalized Oppenheimer–Snyder gravitational collapse into regular black holes
Authors: Shojai F , Sadeghi A , Hassannejad R 
Published: February 2022

Abstract
We shall study the formation of a particular class of regular black holes (BHs) from the gravitational collapse of a massive star. The inside geometry is described by spatially flat Friedmann–Robertson–Walker (FRW) metric and the stellar matter is distributed uniformly without any pre-assumption about its equation of state. Our model is a generalization of Oppenheimer–Snyder collapse for regular BHs. We have obtained the density and pressure of star by applying the condition of smooth joining of metrics at the freely falling surface of star. Specifying the regular BHs to Hayward and Bardeen cases, we see that the stellar matter is described by a polytropic equation of state and moreover, for the radius smaller than a certain value, the strong energy condition becomes invalid. Then for both BHs, the interior apparent and event horizons and also the stellar surface are obtained as functions of the proper time of star. At the end, we have constructed a new two parametric family of regular BHs jointed smoothly to the flat FRW interior metric of a polytropic star with an arbitrary index.
Development and evaluation of a generalized model of RAIM availability for single-, dual- and multi-satellite faults
Authors: Ma Xiaping , Yu Kegen , He Xiaoxing , Li Qinzheng , Zhao Lidu , Wang Haicheng 
Published: February 2022

Abstract
Receiver autonomous integrity monitoring (RAIM) fault monitoring and identification requires first to judge the geometric distribution of currently visible satellites based on performance indicators and to determine whether it is suitable for integrity monitoring, that is, to judge the availability of the RAIM algorithm. With the rapid development of the global navigation satellite system (GNSS), the possibility of dual-satellite faults and multiple-satellite faults in GNSS navigation and positioning has greatly increased. The existing literature mainly focuses on RAIM availability evaluation for single-satellite fault or dual-satellite faults, ignoring the occurrence possibility of multiple-satellite faults, and thus there is no unified RAIM availability evaluation model. To this end, we use the characters of the quadratic matrix to derive a generalized model of RAIM availability evaluation, and the model is suitable for situations of single-, dual- and multi-satellite faults. Based on the observation data of Beidou Navigation Satellite System (BDS) from 332 International GNSS Service (IGS) stations distributed globally on 24 March 2021 and the global ephemeris file, the global RAIM availability of BDS is evaluated. The results show that the generalized model of RAIM availability evaluation has a rigorous derivation process, strong applicability and easy implementation. When the cutoff elevation angle is greater than 5°, the average number of BDS visible satellites at 332 IGS stations worldwide is 12.289 and the average geometry dilution of precision value is 8.090. This can fully meet RAIM availability evaluation and integrity monitoring requirements at most IGS stations and regions. The RAIM availability of triple-satellite faults is lower than that of dual-satellite faults, and the RAIM availability of dual-satellite faults is lower than that of single-satellite fault. For the three different faults, the RAIM availability cannot fully satisfy the four stages in aviation all over the world. Among them, the RAIM availability is highest in the en-route (oceanic/continental low density) stage for all three types of faults, which is 93.146%, 74.848%, and 67.576%, respectively, while the non-precision approach stage has the lowest RAIM availability, which is 78.193%, 13.636%, 3.333% for the three types of faults, respectively.
Interpreting radial correlation Doppler reflectometry using gyrokinetic simulations
Authors: Ruiz Ruiz J , Parra F I , Hall-Chen V H , Christen N , Barnes M , Candy J , Garcia J , Giroud C , Guttenfelder W , Hillesheim J C , Holland C , Howard N T , Ren Y , White A E 
Published: February 2022

Abstract
A linear response, local model for the DBS amplitude applied to gyrokinetic simulations shows that radial correlation Doppler reflectometry measurements (RCDR, Schirmer et al 2007 Plasma Phys. Control. Fusion
49 1019) are not sensitive to the average turbulence radial correlation length, but to a correlation length that depends on the binormal wavenumber

k

⊥

selected by the Doppler backscattering (DBS) signal. Nonlinear gyrokinetic simulations show that the turbulence naturally exhibits a nonseparable power law spectrum in wavenumber space, leading to a power law dependence of the radial correlation length with binormal wavenumber

l
r

∼
C

k

⊥

−
α

(
α
≈
1
)

which agrees with the inverse proportionality relationship between the measured

l
r

and

k

⊥

observed in experiments (Fernández-Marina et al 2014 Nucl. Fusion
54 072001). This new insight indicates that RCDR characterizes the eddy aspect ratio in the perpendicular plane to the magnetic field. It also motivates future use of a nonseparable turbulent spectrum to quantitatively interpret RCDR and potentially other turbulence diagnostics. The radial correlation length is only measurable when the radial resolution at the cutoff location

W
n

satisfies

W
n

≪

l
r

, while the measurement becomes dominated by

W
n

for

W
n

≫

l
r

. This suggests that

l
r

is likely to be inaccessible for electron-scale DBS measurements (

k

⊥

ρ

s

>
1

). The effect of

W
n

on ion-scale radial correlation lengths could be nonnegligible.
Space evidence of enhanced photosynthetic carbon uptake under fragmented temperate forests
Authors: Li Jiawei , Ma Jun , Xu Jingxian , Tang Yanan , Wang Quanbo , Song Guohua , Qi Guanpu 
Published: February 2022

Abstract
Global changes arouse large-scale fragmentation of forests, which has a profound impact on the balance of the global carbon cycle. However, the effect and process of temperate forest fragmentation on photosynthetic carbon uptake are not clear. We used remote sensing datasets to describe the degree of forest fragmentation and clarify the relationship between fragmentation and photosynthetic carbon uptake in the temperate forests of northeastern China. The results show that forest fragmentation has high spatial heterogeneity and promotes photosynthetic carbon uptake by 14% in the cold temperate zone and 10% in the middle temperate zone. Hydrothermal conditions are the dominant influencing path, explaining 60% of the variation in the cold temperate zone and 49% of the variation in the middle temperate zone. In addition, temperature is the dominant driver of the cold temperate zone, and water is the dominant driver of the middle temperate zone. Our research calls for a deeper understanding of the carbon cycle of fragmented temperate forests, and it is necessary to consider appropriate human intervention in forest management.
Effects of molecular diffusion length on area-selective growth of organic patterns
Authors: Jiang Yue , Cai Yichen , Li Jianping , Chen Naibo , Hu Laigui , Wang Wenchong , Nie Qing-Miao , Yan Bo 
Published: February 2022

Abstract
Oganic devices have gained much progress in the past decades, as a promising candidate for flexible/wearable electronics. However, the realization of organic microelectronic systems for wide applications is still difficult, due to the incompatibility of organic semiconductors (OSCs) with the conventional top-down lithography techniques for inorganics. To solve this challenge, bottom-up lithography-compatible methods have been developed for organic device arrays, i.e., template-directed growth or area-selective growth (ASG). Unfortunately, the physics on the dynamic process of the ASG method for molecular semiconductors is still not well understood. In order to explore this issue, the growth of particles on prepatterned surfaces under different diffusion lengths (L

d
) was simulated in a microscopic point of view by using kinetic Monte Carlo method. Simulation results show that ASG of the particles is strongly related to the L

d
of the particles, periodicity and size of prepatterned surfaces. It is notable that such simulated results were found to fit well with those of our experiments, which can be favorable for improving the ASG method for patterning functional molecules.
Microstructure characterization and mechanical behaviour of laser additive manufactured ultrahigh-strength M54 steel
Authors: Zhao Zhong-Chao , Ning Jing , Su Jie , Jiang Qing-Wei , Liu Geng , Liu Ding-Hui , Gao Qi , Wang Ao 
Published: February 2022

Abstract
Ultra high-strength M54 steel blocks were fabricated by laser metal deposition. The microstructure and mechanical behavior of the material were investigated systematically. The microstructure of the as-deposited M54 steel is anisotropic; the cross-section (XOY plane) has a cellular structure, whereas the longitudinal section (XOZ and YOZ planes) shows a mixture of alternating cellular and columnar forms. Compositional segregation is present at the cell walls (interdendritic regions) in the as-deposited state, resulting in retained austenite at the cell walls. The cross-sectional XOY plane contains 10.08% austenite, whereas the XOZ and YOZ planes contain 24.59% and 22.4% austenite, respectively. The retained austenite at the cell wall (interdendritic region) has low thermal and mechanical stability and disappears after the cryogenic treatment or is transformed into martensite during a tensile test. The as-deposited samples show anisotropic mechanical properties. The transverse samples exhibit stronger transformation-induced plasticity (TRIP) and work hardenability with a lower yield strength of 662 MPa and higher ultimate strength of 1982 MPa, corresponding to a higher amount of retained austenite in this direction. The longitudinal ultimate strength and yield strength are 1832 MPa and 997 MPa, respectively. The ductility and toughness are also largely anisotropic, and their reduction in the transverse direction is only 1/3 of that in the longitudinal direction. The Vickers hardness of the microstructure increases slightly from the bottom to the middle and upper part of the sample due to less thermal cycling in the upper part.
Influence of tool pin profiles in the strength enhancement of friction stir welded AA5083 and AA5754 alloys
Authors: Kumar P Naveen , Jayakumar K 
Published: February 2022

Abstract
Friction stir welding (FSW) is a well-known technology for joining similar and dissimilar materials. The quality of the weld in FSW is affected by the various process parameters such as tool rotational speed (TRS), tool transverse speed (TTS) and tool pin profiles. This study aims to investigate the effect of three different tool pin profiles on the variation of microstructure and mechanical strength of friction stir welded AA5083 and AA5754 alloys joints. Both of these alloys combinations offer excellent corrosion resistance and formability. As a result, they’re commonly seen in tanks, pressure vessels, shipyards, and trucks. In this work, the FSW methodology focused on varying the TRS of 750, 1000, 1250 and 1500 rpm and TTS as 20, 30, 40 and 50 mm min−1. The surface microstructures of the weldments were analyzed using an optical microscope and scanning electron microscope. Tensile and Microhardness tests were carried out on the weldments to determine the weld strength. Three variety of tool pins, namely straight square, threaded cylinder, and straight cylinder were used for this study. The microstructural and the mechanical properties analysis of the welded samples proved that the straight square tool pin profile is suitable for joining AA5083 and AA5754 alloys. The weldments prepared using a straight square pin profile exhibited good material stream behaviour, uniform spreading of plastic deformation in the weld zone and aided in the reduction of formation of macroscopic defects on the welded zone. Among the process parameters, it was detected that the pin profile displays more impact on tensile strength followed by tool rotation speed and welding speed. According to the findings, the dissimilar weld joint formed at the optimum process parameters had the highest tensile strength of 212 MPa and hardness of 88 HV were: Square Tool Profile, 1250 rpm TRS, and 40 mm min−1 TTS.
Deep learning modeling strategy for material science: from natural materials to metamaterials
Authors: Li Wenwen , Chen Pu , Xiong Bo , Liu Guandong , Dou Shuliang , Zhan Yaohui , Zhu Zhiyuan , Chu Tao , Li Yao , Ma Wei 
Published: February 2022

Abstract
Computational modeling is a crucial approach in material-related research for discovering new materials with superior properties. However, the high design flexibility in materials, especially in the realm of metamaterials where the sub-wavelength structure provides an additional degree of freedom in design, poses a formidable computational cost in various real-world applications. With the advent of big data, deep learning (DL) brings revolutionary breakthroughs in many conventional machine learning and pattern recognition tasks such as image classification. The accompanied data-driven modeling paradigm also provides transformative methodology shift in materials science, from trial-and-error routine to intelligent material discovery and analysis. This review systematically summarize the application of DL in material science, based on a model selection perspective for both natural materials and metamaterials. The review aims to uncover the logic behind data-model relation with emphasis on suitable data structures for different scenarios in the material study and the corresponding problem-solving DL model architectures.
102 Quality of Life After Intestinal Stoma: A Cross Sectional Study Among a Sample of Sudanese Patients
Authors: Mohammed O.A.A. , Osman S.M.A. , Mohammed A.A.A. , Hussein S.A.A. , Alkhedir S.E.O. , Mirghni S.A.A. , Koko A.I.E.A. , Saad E. , Salman M.S.T. , Suleiman S.H. 
Published: February 2022

Abstract

Aim
The effects of stoma surgery are multiple, and patient’s quality of life is affected in many ways. Stoma is increasingly used as surgical technique in Sudan, however; studies assessing its effects are lacking.

Method
a descriptive cross-sectional study was conducted in 3 hospitals in Khartoum state. Patients were interviewed using structure questionnaire

Results
65.9% (27) of the patients were males, the mean age was 44.36 (±14.3) and 36.6% had primary school education. 43.9% were unemployed. Mean duration of stoma was 10.67(±10.5) months, and it was temporal in 61% (25). Colorectal cancer was the most indication for the stoma. 70.7% (29) were married, 34.3% (12) reported change in their work after surgery and 68% (17) said it was due to the stoma surgery. Of those who were sexually active, 45.2% (14) didn’t resume their sexual life after it, and most of those who returned report it not to be satisfactory. The entire social and most of the religious practices were found to be statistically different before and after surgery. The mean score for the psychological quality of life was 58.47 (±13.32) out of 80.

Conclusions
Although stoma patients generally have poor quality of life, they struggle in sexual, social, work, and religious aspects. Patients have good psychological quality of life. Efforts to improve the quality of life and incorporation into the community are needed
143 Intestinal Failure: Epidemiology, Catheter Related Sepsis and Challenges
Authors: Ballanamada Appaiah N.N. , Probert S. , Boyle K. , Rogers D. , Stewart J. , Baker M. 
Published: February 2022

Abstract

Background
The aforementioned service provides specialist intestinal failure care to patients in Leicestershire and surrounding counties.

Aim
To study the epidemiology of IF cases referred to the service & review outcomes particularly the indications and delivery of parenteral nutrition (PN). To review catheter-related sepsis (CRS) rates and identify areas for improvement.

Method
Service data from January 2016 to November 2017 was analysed retrospectively. Descriptive and inferential statistical analysis was carried out. Chi-square/ Fisher Exact tests were used to identify significance on categorical data and non-parametric settling was used for qualitative data analysis.

Results
365 patients were referred to the service from January 2016 to November 2017. 58% patients had grade I intestinal failure. 34% and 24% referrals were made by the colorectal and hepato-pancreato-biliary (HPB) units respectively. Gut rest (27%) and bowel obstruction (25%) were the most common indications for nutritional support. Duration of PN requirements varied greatly, but most patients (39%) patients required it for up to 7 days. Single lumen PICC line (64%) and cephalic vein (54%) were the most commonly used catheter and site of vascular access respectively. Chronicity of IF and number of vascular catheters required to provide PN were significantly associated with rates of CRS.

Conclusions
CRS was found to be statistically significantly associated with chronic IF and number of vascular access catheters required to provide PN. Cost implication and morbidity of CRS could be analysed further to identify other ways to provide safer and cost-efficient parental nutrition for patients with intestinal failure.
257 Comparing Practice Testing to Restudying in the Dissecting Room: An Experimental Study
Authors: Elhassan A.B.E. , Ibrahim A. , Saad M. , Awad K. , Salman M.S.T. , Mohammed O.A.A. , Ali M. , Bashir S.A.T. , Mohamed N.E.M. , Mohammed M.A.A. 
Published: February 2022

Abstract

Aim
Medical students employ many strategies for learning, most commonly restudying. However, evidence suggests that restudying is not as effective as other strategies, namely practice testing. Different studies have compared restudying to practice testing on a variety of subjects. Few studies have assessed the effect of practice testing in anatomy courses. To the best of the authors' knowledge, no studies have investigated practice testing in the dissecting room (DR). In this study, we aim to measure the effect of practice testing in a DR setting, as compared to restudying.

Method
Second-year medical students learning the cardiovascular system were included in the study. Two groups were randomly selected to participate in practice tests taken at the end of DR sessions. The other two groups were asked to restudy the material. At the end of the four-week course, all students took a 15 points multiple-choice exam on learned material. Authors of practice tests were blind to the final exam content and vice versa.

Results
One hundred eight students participated in the study. Fifty-three students were in the practice testing group, and 55 were in the restudying group. The practice testing group performed significantly better than the restudying group (p = .008), with a mean of 8.57 +/- 2.3 for the practice testing group and 7.27 +/- 2.6 for the restudying group.

Conclusions
Practice testing significantly improved retention of Anatomy. We recommend that practice testing is implemented regularly at the end of DR sessions to enhance the learning experience.
266 Improving Management of Women Presenting with Groin Hernias at Royal Devon and Exeter Hospital (RD&E)
Authors: Chillarge G. 
Published: February 2022

Abstract

Aim
Determine the percentage of women with groin hernia undergoing laparoscopic repair at RD&E hospital and if it was offered during clinic visit.

Background
The lifetime risk of groin hernia in women is 3–5.8%. The incidence of missed femoral hernia at re-operation after open repair in women is 41%. The HerniaSurge group has recommended laparoscopic repair of all groin hernias in women as it offers opportunity to identify all types of groin hernias and reduces post-operative pain and recurrence.

Method
All female patients undergoing groin hernia surgery at RD&E hospital from 1 Feb 2018–31 Jan 2020 were identified. Patients undergoing surgery after this period were not included as the surgical practice was changing due to COVID-19 pandemic. Electronic patient records including clinic letters, operative notes, radiology reports and follow up letters were reviewed.

Results
117 female patients undergoing groin hernia repair were identified. During clinic visit, rationale for laparoscopic surgery was documented only in 29/117 while discussion regarding material risks of surgery was documented in 51/117. Only 41/117 (35%) patients underwent laparoscopic hernia repair.

Conclusion and second cycle
The current practice at RD&E requires improvements in terms of documentation of material risks associated with groin hernia repair and offering laparoscopic repair for women with groin hernias. For the next cycle, we aim to present at the local audit meeting and then collect further data to evaluate improvements in practice. We also aim to create a standardised electronic clinic letter and operative note format to bring uniformity of care.
330 An End to Doctor’s Handwriting in the Digital Age: Evaluating the Legibility of Operation Notes in Otolaryngology
Authors: Bhojwani D. , Javed H. , Amala C. , Hashmi S. 
Published: February 2022

Abstract
According to GMC Good Medical Practice, clinicians must record their work ‘clearly, accurately and legibly’. Operation notes are no exception and have several key functions. They serve reminder of procedural events, communicate information to the wider team and may be used as evidence when there are complications or complaints.
The aim of this audit was to evaluate the legibility of operation notes within the Otolaryngology department at Peterborough City Hospital.
Handwritten operation notes were audited from 8 dates chosen at random over a 2-month period (n = 27). Multiple surgeons and a variety of operations were included. Parameters such as legibility of the surgeon’s name, patient identification, date, name of procedure, events, findings, closure and post-op instructions were recorded.
Only 11% of the operation notes were legible in all relevant parameters. The surgeon’s name was either absent or not identifiable from the handwriting in 48%. Documentation of the procedure itself and post-op instructions was illegible in 18% and 29% of notes respectively.
Illegibility of operation notes is ultimately a patient safety-issue. Not only does it contribute to confusion about what happened during the surgery but also leaves room for error in terms of post-operative care and follow up. The results of the audit were discussed as part of a departmental meeting to highlight the importance of readable operation notes and help foster a culture of good record keeping.
A switch to computerised operation notes could ensure legibility and thus improve standards of patient care in the hospital.