bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Power domination of graphs
Authors: Prabha R , Thenmozhi B
Published: April 2021

Monitoring an electric power system with a minimum number of PMUs is related to the domination problem in graph theory. In this paper, we introduce a new graph invariant called global power domination number. A power dominating set S of a graph G = (V, E) is a global power dominating set if S is also a power dominating set of

G
¯

. The global power domination number γgp
(G) is the minimum cardinality of a global power dominating set. In this paper, we initiate the study of global power domination problem and prove its NP-completeness. We also characterize the global power domination number for trees and compute the exact value of γgp
(G) for certain families of graph.
An Algorithmic Approach for Encryption using Graph Labeling
Authors: Amudha P. , Jayapriya J. , Gowri J.
Published: April 2021

In the recent computerized world, cryptography plays an important role so as to transfer information safely between at least two substances. Cryptography consists of two parts, one is encryption of the message so that the cypher text will not reveal the original message to anyone. The other par is decryption at the receiver’s side which invers the encryption process and restore the original message. There are numerous encryption calculations exist we are in the position to find out some new non-usual encryption algorithms to secure the information. The suggested algorithmic approach speaks a new encryption technique to encode and decode the message very securely using graph labeling.
A study on distance k-domination in digraphs
Authors: Joeshi Annie Vetha V. , A. Anto Kinsley
Published: April 2021

Let D = (V, A) be a finite and simple directed graph (digraph) with vertex set V and arc set A. For an integer k ≥ 1, the out k-neighborhood of a vertex ν is defined as

N
k
+

(
ν
)

=

{

u
∈

V
(
D
)
/

d
→

(
ν
,
u
)

≤

k

}

. A set S ⊆ V is said to be a distance k-dominating set in D if N+
k
(S) ∪ S = V. The minimum distance k-dominating set in D is the distance k-domination number,

γ

k
→

(
D
)

. For two integers s ≥ 2 and k, the (s, k) - kernal set and the (s, k) - kernal number,

ξ

k
→

(
D
)

are studied. This parameter

ξ

k
→

(
D
)

is also computed for different types of digraphs. Strong digraphs (SDs) are studied and

γ

k
→

(
D
)

of SDs are determined in terms of the radius and diameter of SDs. Also (2, k) - kernals of directed wounded spider are classified with

ξ

k
→

(
D
)

. Some upper and lower bounds on

γ

k
→

(
D
)

are determined and characterized some digraphs achieving these bounds.
Arc and twin arc domination in Cayley digraphs
Authors: Rajeswari R. , Anbunathan R.
Published: April 2021

Let G be a finite group and let S be a generating subset of G. The Cayley digraph Cay (G, S) is the digraph with node set as the elements of G and there is an arc from u to us whenever u ϵ G and s ϵ S. An arc e1 in a digraph D out arc dominates itself as well as all arcs ei. Such that {e1, ei} is a directed path of length 2 in D. While e1 in arc dominates both itself and all arcs ej such that {ei, e1} is a directed path of length 2 in D. The arc domination number is the minimum cardinality of an out arc dominating set of D denoted by γ′(D). A set of edges of D is twin arc dominating set if every edge of D is out arc dominated by some edge of S and in arc dominated by some edge of S. The minimum Cardinality of a twin arc dominating set is the twin arc domination number denoted by γ* (D) of D. This paper discusses the arc domination and twin arc domination of Cayley digraphs and attempts to find bounds for the arc domination number of the same class of graphs.
SSP-Structure of Closed Helm and Flower Snark Graph Families
Authors: Mary Jeya Jothi R , Revathi R , Angel D
Published: April 2021

A graph is SSP (Super Strongly Perfect) if all of its (induced) subgraph H in G obsesses a (minimal dominating set) MDS that link up all of its cliques (maximal) in H. In this paper, SSP Structure along with its parameters (counting of maximal cliques, cardinality of dominating set (Minimal) and colourability of closed Helm graph is analysed and also Flower snark graph families are investigated.
SSP-Structure of k-Sun Flower, Friendship and Jahangir Graphs
Authors: Mary Jeya Jothi R , Revathi R , Angel D
Published: April 2021

A graph is SSP (Super Strongly Perfect) if all of its (induced) subgraph H in G obsesses a (minimal dominating set) MDS that link up all of its cliques (maximal) in H. It is offered the cyclic structure of k-sun flower graph, friendship and Jahangir graphs and later explored their SSP parameters like counting of colourability, MDS (minimal dominating set) and cliques (maximal) of these graphs.
Modelling and Reliability Analysis of Power Cables Used as a Two Unit Hot Standby System with Preference of Repair over Replacement in the Metro Railways
Authors: Pandey R , Parashar B , Khemchandani V , Pandey P , Bhardwaj N
Published: April 2021

In this study we aim to do an analysis of the profitability and reliability of a system used primarily in Metro Train Networks consisting of a power cable rated for 33KV. The wires for the feed to each substation are laid in loops. As a starting point, two cables of the same voltage are laid with one being operational and another being a hot standby for backup. The moment the primary operational cable fails the backup cable immediately becomes operational. In the situation of a cable failure, it is considered if repairing the damaged cable can be done as opposed to repairing it. The moment both the operational as well as the back-up cables fail, the system is brought to a complete halt. Cable failures are categorized in two groups viz. irreparable failures & repairable failures. Regenerative Point Technique & Semi-Markov Processes are the methodologies used to derive the data that depicts real-failure situations or any other parameters of system effectiveness. This analysis is being done to enable multiple cases to detect and realize essential profit-analysis results for the system in question.
A Hybrid Model Approach for the Prediction of Rainfall
Authors: Mallika M. , Nirmala M.
Published: April 2021

For maintaining the atmospheric balance, precipitation is very much helpful. Rainfall is one of the forms of precipitation Though excess rainfall causes several damages to the earth in various ways, it is considered very precious as it is one of the essentials for the existence of human beings. As a result, a prediction of rainfall also forms a major part in planning things. This paper proposes a new hybrid model Moving average-kNN for doing the prediction. Error measures Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), and Mean Absolute Error (MAE) have been used for the validity of the model.
Leaf Classification Based on Convolutional Neural Network
Authors: Wu Peng , Qian Zhou
Published: April 2021

Convolutional Neural Network (CNN), a very important neural network structure in deep learning, is a network model often used in image classification, target recognition and other fields. In botany, leaf classification and recognition is very important for identifying new or scarce tree species. In nature, plants are widely distributed, and the survival and development of all living things on the earth depend on plants. Identification of species by leaves and related research are of great help to the study the evolution law of plants, the protection of plant species and the development of agriculture. This paper uses convolutional neural network in artificial intelligence to identify the leaves of several kinds of trees collected by Kunming Institute of Botany, Yunnan Province, which can realize the automatic extraction of leaf image features, reduce tedious labor costs, and realize the use of artificial intelligence to classify leaves, thus providing an auxiliary means of artificial intelligence for botany research.
High Value Bit Model Reconstruction and Damage Identification Based on Binocular Robot
Authors: Yan Jingsen , Hao Weidong , Yang Daoguo , Wang Ruiqing
Published: April 2021

In order to achieve high value bit repair, bit model reconstruction and damage identification must be carried out. In this paper, the binocular camera and the industrial robot were combined to realize the point cloud acquisition, model reconstruction and damage identification of the bit. The bit damage data obtained by this method was applied to the repair experiment of the bit and the repaired bit met the requirements of re-use.
Research on Database Programming Technology in Computer Software Engineering
Authors: Quan Zhi , Pu Caiyun
Published: April 2021

With the continuous progress of economy and society and the development of science and technology, the application of computer has entered all aspects of people’s life, integrated into various industries, and then promoted the development of the industry. The core technology in computer technology is mainly computer software engineering, while the core technology in computer software engineering is database programming technology.Therefore, a large number of software staff are needed to study this, so as to promote the continuous progress and sustainable development of database programming technology.
Research on high security of IP tunnel in virtual private network
Authors: Gan Weimin , Yin Xiaogui
Published: April 2021

IPSec encrypts and authenticates the packets of IP protocol. Both sides of IP network layer communication use encryption authentication, data source authentication and integrity verification to ensure the integrity, confidentiality and anti replay of IP protocol packet transmission. In enterprise network management, we can usually use IPSec VPN technology to establish a secure channel to realize the secure communication between headquarters and branches.[1]
Research on Key Technologies of Intelligent Operation and Maintenance of Communication Network
Authors: Wang Lu , Zhao Yu , Chen Zhikun
Published: April 2021

Based on the analysis of the challenges faced by the operation and maintenance of communication network, this paper studies the intelligent operation and maintenance architecture of communication network. Using the accumulated massive communication network operation and maintenance data, the research explores the high-speed calculation of intelligent algorithm, rapid splicing of demand components, multi-dimensional visual interaction and other technical methods to effectively deal with the problems such as the surge of business volume, the difficulty of event handling, and the lack of personnel training. Research on key Technologies can ensure the safe and stable operation of information and communication network.
Improve Visual Question Answering Based On Text Feature Extraction
Authors: Wang Jing , Dong Yang
Published: April 2021

VQA requires the machine to be able to answer questions related to the image based on the image. VQA is mainly divided into four modules: text extraction module, image extraction module, text-image feature fusion module and answer prediction module. In this paper, the most mainstream VQA2.0[1] data set is selected for experiment, and the text extraction module is improved on the basis of a baseline model. The Glove vector is used to preprocess the problem text data, and the GRU network replaces the traditional LSTM network encoding and processing text vector. Experimental results show that the improvement of the text extraction module improves by 2.42% on the basis of the original model, and the GRU network can also accelerate the training speed.
Research on network information security penetration test based on IP port service technology
Authors: Wang Xiaoyu , Li Dandan
Published: April 2021

Network information security penetration test is an important means to intercept network information attacks after obtaining user authorization. At present, various network information security penetration testing technology system research work is also constantly improving and updating. However, due to the increasingly complex verification of hacker behavior, the research of network information security penetration test is still difficult to meet the requirements of the current information development. In this environment, this paper proposes a network information security penetration test method based on IP port service technology, and describes a set of penetration test ideas, steps and results, for network managers to reference, to achieve the network information security penetration test Finally, it was confirmed by experiments, The efficiency and ability of penetration test are improved, and the process of penetration test is optimized.
Distributed authentication scheme for Industry Internet Platform application based on consortium blockchain
Authors: Yan Min , Huang Haibo , Yang Shuaifeng
Published: April 2021

With the rapid development of industrial internet services, the integration of IT/OT has enabled the continuous expansion of network security boundaries and put forward higher requirements for platform application cross-domain identity authentication. Aiming at the insufficient security of existing user-centric identity authentication schemes, this paper proposes a distributed authentication scheme based on the consortium blockchain in industrial Internet platform. The solution analyzes its applicability to the Industry Internet Platform from three perspectives: network architecture, industrial Internet platform user identity control, and user privacy. It defines the identity composed of consortium ID and consortium digital identity credentials, and builds distributed authentication architecture. The consortium blockchain is used to record the digital identity information of the industrial Internet platform users, and the consortium ID and the consortium digital identity credential are designed to realize the industrial Internet platform business securely access.
Research on Structure Data Link Detection Method Based on Internet of Things System
Authors: Yu Wenwu , Zhai Yue , Guo Yang , Ji Meijiao
Published: April 2021

In order to improve the fault diagnosis and analysis capabilities of the cyber-physical system in the Internet of Things, it is necessary to detect and identify the vicious data chain of the cyber-physical system in the Internet of Things. Moreover, to realize the detection and identification of the vicious data link in the cyber-physical system in the Internet of Things, a fast extraction algorithm for the vicious data link of the cyber-physical system in the Internet of Things is proposed in the paper to collect vicious data from the cyber-physical system in the Internet of Things. In addition, the malignant data generated during the factor adjustment of the Internet of Things can be divided into periodic structure and non-periodic structure in structure, and the malignant data sensor network model of the cyber-physical system in the Internet of Things is constructed. Therefore, through simulation experiment analysis, the method proposed in the paper has superior performance in the detection and identification of vicious data links in the cyber-physical system of the Internet of Things.
Application and Practice of VR Technology in Basic Computer Teaching in Art Colleges
Authors: Liu Juan
Published: April 2021

In the process of basic computer teaching in art colleges, the use of virtual reality technology can improve the efficiency of basic computer teaching and ensure the quality of teaching. At present, virtual reality technology is also constantly maturing and improving. The full application of virtual reality technology in the basic computer teaching of art colleges is conducive to saving teaching costs. This can not only give full play to the application value of virtual reality equipment, but also reduce the loss caused by teachers’ continuous operation in the teaching process, and improve the teaching effect. However, it should be noted that in the process of basic computer teaching in art colleges, there are also some problems in virtual reality technology. We need to conduct in-depth research and analysis on these problems. This article discusses the practical strategies of virtual reality technology in the basic computer teaching of art colleges, hoping that these strategies can really improve the basic computer teaching level of art colleges.
Research on spectrum scheduling based on discrete artificial bee colony algorithm
Authors: Xiao Ying , Chen Dianjun , Zhang Lu Yong
Published: April 2021

With the increasing shortage of spectrum resources on the earth, how to ensure the high-quality transmission of satellite wireless signals to the ground has become one of the most important problems in the current satellite ground communication system. In order to schedule spectrum resources more reasonably and efficiently, we propose a spectrum resource scheduling model based on adaptive chaotic distributed differential artificial bee colony algorithm. The algorithm uses chaotic distribution to generate initial solution. In the search phase, differential evolution strategy and artificial bee colony algorithm are used to work in parallel to find the local optimal solution. The selection operator is used to calculate the probability of selecting new bee sources, which improves the reliability and convergence speed of the algorithm. Finally, the results show that in single-channel and multi-channel scenes, the algorithm can help to improve the fairness and throughput.
Bridge defect detection technology based on machine vision and embedded
Authors: Xie Yufei , Ming Sheng
Published: April 2021

In order to improve the degree of intelligence of bridge body maintenance, reduce the consumption of manpower and material resources, and improve inspection efficiency, the technology of machine vision inspection is proposed, and a method of detecting bridge body surface defects and embedded design image transmission and positioning is studied. This paper introduced the existing detection methods and technologies of bridge cracks, and analyzed the detection methods of bridge cracks based on image processing and convolutional neural networks. On the basis of this research, the project collected information and processed and analyzed the cracks on the actual bridge deck, and obtained the image preprocessing results of grayscale, removed background noise, thresholded segmentation, and retained edge information and high-frequency signals. And further, the project used drones to capture image data and used deep learning algorithms to achieve automatic detection of aerial crack images. This scheme can effectively reduce the impact of road background and noise on the detection of bridge surface defects.
Research on Sentiment Analysis Model Due to COVID-19 Using Social Media
Authors: Li Zhijie , Wang Xiaodan
Published: April 2021

Since the outbreak of the disease in early 2020, it has received worldwide attention and become a hot topic of discussion on social media. This paper crawled more than eight billion tweets from the first inflection point of the global outbreak of the epidemic, extracted several prominent hot topics related to the epidemic through two objective and intuitive means, namely LDA model and generated words, and then compared and analyzed the degree of subjectivity and positivity of their tweets for ‘lockdown’, ‘mental health’ and other topics. The experimental results showed that the number and active degree of global Twitter users’ tweets on the above epidemic hot topics were most correlated with the number of newly diagnosed patients after 12 days. Comments are generally more positive to lockdown than to mental health. For all tweets about the epidemic in India and Wuhan, the positive degree of tweets judged as objective was relatively stable, while the positive degree of subjective tweets fluctuated greatly, which verified the rationality and effectiveness of the model for subjective and objective classification. Among the tweets judged as subjective by the model, the positive component of sentiment analysis was more. Most tweets about the epidemic in India and Wuhan were positive, and the fluctuation degree of subjective and objective curves verified the rationality and effectiveness of the model for subjective and objective classification.
Biocompatibility and degradation of the open-pored magnesium scaffolds LAE442 and La2
Authors: Kleer-Reiter N , Julmi S , Feichtner F , Waselau A-C , Klose C , Wriggers P , Maier H J , Meyer-Lindenberg A
Published: April 2021

Porous magnesium implants are of particular interest for application as resorbable bone substitutes, due to their mechanical strength and a Young’s modulus similar to bone. The objective of the present study was to compare the biocompatibility, bone and tissue ingrowth, and the degradation behaviour of scaffolds made from the magnesium alloys LAE442 (n= 40) and Mg-La2 (n = 40) in vivo. For this purpose, cylindrical magnesium scaffolds (diameter 4 mm, length 5 mm) with defined, interconnecting pores were produced by investment casting and coated with MgF2. The scaffolds were inserted into the cancellous part of the greater trochanter ossis femoris of rabbits. After implantation periods of 6, 12, 24 and 36 weeks, the bone-scaffold compounds were evaluated using ex vivo µCT80 images, histological examinations and energy dispersive x-ray spectroscopy analysis. The La2 scaffolds showed inhomogeneous and rapid degradation, with inferior osseointegration as compared to LAE442. For the early observation times, no bone and tissue could be observed in the pores of La2. Furthermore, the excessive amount of foreign body cells and fibrous capsule formation indicates insufficient biocompatibility of the La2 scaffolds. In contrast, the LAE442 scaffolds showed slow degradation and better osseointegration. Good vascularization, a moderate cellular response, bone and osteoid-like bone matrix at all implantation periods were observed in the pores of LAE442. In summary, porous LAE442 showed promise as a degradable scaffold for bone defect repair, based on its degradation behaviour and biocompatibility. However, further studies are needed to show it would have the necessary mechanical properties required over time for weight-bearing bone defects.
Machine Learning Based Model to Predict Stock Prices: A Survey
Authors: Harikrishnan R , Gupta Aksh , Tadanki Namrata , Berry Ninad , Bardae Ramya
Published: April 2021

In this survey paper, we provide the findings obtained from extensive reading of 35 research papers that span the financial domain (specifically the Stock Market) as well as explore various Machine Learning algorithms and offer a comparative analysis of the same. Through this, we observed that there is a general preference towards Technical Indicators and how a new trend of using Hybridized Indicators is emerging. We also show that Support Vector Machines have been constantly preferred due to their ability to handle complexity but new alternatives like Auto Regressive Integrated Moving Average and Long-Short Term Memory models are on the rise.
Evaluation of trapping parameters of europium doped tristrontium dialuminium oxide phosphor by different thermoluminescent analysis methods
Authors: Jha Piyush , Khare Ayush
Published: April 2021

In the present work, we have synthesized Europium (Eu) doped Tristrontium Dialuminium Oxide (Sr3Al2O6:Eu) phosphor by solid state reaction method in air atmosphere. The thermoluminescence (TL) properties of the synthesized phosphor are investigated and presented. Theoretical analysis of glow curves of Sr3Al2O6:Eu was done by computerized glow curve deconvolution (GCD) method, and the trapping parameters of the synthesized phosphor, such as activation energy, frequency factor, order of kinetics, etc. are discussed and explained. These trapping parameters are determined by different methods, such as Chen’s peak shape method, initial rise method, and Ilich method. The synthesized phosphor is found to be a good candidate for dosimetric applications.
Adsorption isotherms and kinetics study for U(VI) removal by excellent sorbent materials graphene oxide and functionalised graphene oxide
Authors: Patel Khilawan , Sutar Alekha Kumar , Maharana Tungabidya
Published: April 2021

In this paper, the graphene oxide (GO) and carboxylic functionalized graphene oxide (COOH-GO) were synthesized for the removal of U(VI) ion in samples of water. The structures of prepared GO and COOH-GO were confirmed by X-ray diffraction (XRD), Scanning electron microscope (SEM), Fourier transformed infrared (FTIR) spectroscopy, Raman spectra, and high-resolution transmission electron spectroscopy (HR-TEM). An adsorption study was carried out for these and it has been found that COOH-GO has more excellent adsorption property at 4.5 pH. The batch adsorption was studied successfully by the effect of initial uranium concentration, pH of the medium, sorbent dose, temperature, and contact time efficiency. The adsorption isotherms were studied successfully for Langmuir and Freundlich. The kinetics were studied successfully and fitted for the pseudo-first-order and pseudo-second-order model. The maximum adsorption capacities at pH 4.5 were calculated for COOH-GO, GO, and graphite. The thermodynamic studies revealed that adsorption is endothermic and spontaneous.
Effect of cadmium sources on the structural, morphological, and optical properties of CdS films for solar cell applications
Authors: Sinha Tarkeshwar , Verma Lekha , Khare Ayush
Published: April 2021

The variations in the structural, morphological, and optical properties of three CdS films deposited with different cadmium ion sources namely cadmium acetate, cadmium chloride, and cadmium sulfate are reported in this article. All three CdS films possess cubic crystalline structure with the most prominent cubic phase (111). The CdS film deposited with cadmium acetate showed the best crystallinity among them. The presence of both Cd and S with a difference in the percentage of its existence depending upon the type of cadmium source chosen is obtained in the elemental analysis of the CdS films. CdS film deposited from acetate based chemical solution exhibited broad transmittance behaviour in the visible wavelength region due to its superior surface morphology. The energy band-gap values for CBD-CdS films deposited with cadmium acetate, cadmium chloride, and cadmium sulfate are found as 2.30eV, 2.23eV, and 2.32eV, respectively. The film deposited with cadmium acetate showed better IR response and more intense PL emission peaks as compared to the other two films. The efficiency of the CdTe/CdS cell fabricated with CdS window layer deposited with cadmium acetate is found to be 10.02%.
Effect of pH on structural, optical, and morphological properties of ED-CdTe film
Authors: Verma Lekha , Khare Ayush
Published: April 2021

Cadmium telluride (CdTe) thin films have been deposited by electrodeposition (ED) technique on fluorine doped tin oxide (FTO) coated glass substrates using an aqueous electrolyte bath solution. The pH-value of the electrolyte solution is one of the most important deposition parameter that should be optimized to achieve high quality photoconductive material. The films have been deposited at different pH values ranging from 1.5 to 3. The structural, optical, and morphological properties of the samples were characterized using X-ray diffraction (XRD), UV– Visible (UV-Vis) spectroscopy, spectroflurophotometer, scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX) techniques respectively. The XRD analysis shows that the ED-CdTe films possess the cubic crystalline structure and the diffraction peak intensity increased significantly after changing the pH values. The direct energy band-gap (Eg=1.44eV) is obtained in optical absorption spectra. The SEM analysis shows very good morphological growth by changing the pH values and the film deposited with lower pH showed more intense PL emission peaks as compared to the other two films. CdTe film deposited at pH 1.5 will be better choice as an absorber layer of a CdTe/CdS solar cell.
Fuzzy modeling of surface roughness during wet turning of AISI D3 tool steel
Authors: Kumar Pawan , Karsh P K
Published: April 2021

In this study, an attempt has been made to develop a Mamdani fuzzy inference system-based predictive model for predicting surface roughness during wet turning of AISI D3 tool steel. The influence of machining parameters on surface roughness is also investigated. The experimental runs were performed on a lathe using Taguchi’s L9 orthogonal array to know the effect of cutting parameters on machining surface roughness. The performance of the fuzzy model was also compared with the regression model. The fuzzy model’s prediction efficiency (92.10%) was found better than the regression model (70.33%). Therefore, the resultant model so developed is found adequate for surface roughness prediction purposes within the parametric range.
Comparative study of mineral and soya bean oil at faulty temperature for transformer application
Authors: Roy Rishabh , Prasad Srikant
Published: April 2021

Mineral oil is one of the most important insulating materials used for electro insulating & cooling of transformers. For monitoring & diagnosing the incipient fault in power transformers, dissolved gas analysis (DGA) technique is used. DGA have some drawbacks such as it requires regular instrument calibration, standard carrier gas and so on. To overcome these drawbacks, Fourier transform infrared spectroscopy (FTIR) & UV- Visible spectroscopy are used to determine dissolved gas present & ageing of oil. Once the gases are quantified from the FTIR result they can be interpreted using various diagnostic methods mentioned in IEEE Std.C57.104-2008. Also, absorption spectroscopy is considered for condition assessment tool to inspect the oil. By adopting Ultraviolet absorption technique, transformer health assessment is developed: UV-Visible spectroscopy is used. As in search of solution to the harmful & ecological problems, due to non-biodegradability & toxicity by mineral oil, the soya bean seed oil was carried out for the production of transformer insulating oil. In this proposed work, we carried out results from both FTIR & UV-Vis spectroscopy for both mineral oil & soya bean oil & compared both oil by preparing samples heated at 150 °C for 24hrs & 48hrs.
Polarization electric field effect on cross-plane thermal conductivity of GaN/InxGa1-xN/GaN superlattice (x ≤ 0.3)
Authors: Pansari Anju , Sahoo Bijay Kumar
Published: April 2021

GaN/InxGa1-xN/GaN superlattice (SL) has electric field at interfaces termed as interfacial polarization electric (IPE) field. In this work, effect of this electric field on cross-plane thermal conductivity (kcp) of the SL is investigated for Indium content x ≤ 0.3. IPE field revises phonon velocity which enhances interfacial scattering and thermal boundary resistance (TBR). This is due to unequal changes in specific heat and phonon velocity which leads to decrease in phonon transmission and more mismatches of acoustic properties of material. This reduces kcp. Room temperature kcp in presence (absence) of IPE field for GaN (10nm)/InxGa1-xN (5nm) SL are 4.652 (5.720) and 4.282 (5.221) Wm−1K−1 respectively, for x=0.1 and 0.3. This work demonstrates that electric field of nitride SL can be utilized to reduce k for optimum thermoelectric power production.
Moving organ toxicity management in radiation therapy with simple fuzzy logic
Authors: Patnaikuni Santosh Kumar , Saini Sapan Mohan
Published: April 2021

The aim of present work is to estimate and manage real time toxicity of moving organ bladder in deciding level of damage using a simple fuzzy logic method. The target and bladder inter-treatment motions are considered in radiation therapy of prostate cancer in the present study. Materials and methods: The prostate target and nearby critical structures like bladder varies due to physiological behaviour during the course of radiation therapy treatment. The total displacement errors of prostate target shift ranging from 0-5 mm s.d. was considered in this study while maintain tumor dose conformity. The Mamdani-type Fuzzy Inference System (FIS) was applied for determine biological acceptable margin using TCP and NTCP parameters. The bladder volume variations with weekly analysis of cone beam CT (CBCT) were considered. Using irradiated volume-risk relationship in planning, the overlapped risk volumes were estimated. Fuzzy rules and membership function were used basis on setup errors, asymmetrical nature of organ motion and limitations of normal tissue toxicity in margin formulations. Results and discussion: The prostate target motion management was in a good consistent with conventional margin formulations at 5 mm s.d. displacement error range to maintain conformity index (CI) of target. With application of conventional margins of target volume, the sub-volumes of critical organs such as bladder and corresponding its NTCP values were fuzzified using inter treatment volume variations of critical organs. The risk factor (RF) of critical organs were qualitatively assessed with for each fractional volume of irradiated to total volume and relevant NTCP values. Conclusion: A simple fuzzy logic may be suitable to estimate critical moving organs toxicity like bladder biologically. Using proposed simple and fast method, there is interplay between volume-risk relationship and NTCP of OARs to management of normal-tissue risk level of radiation therapy.
A new type of low density cement slurry suitable for sandstone formation
Authors: Zeng Jia , You Fuchang
Published: April 2021

Unconsolidated sandstone reservoir is an important unconventional oil and gas resource with the characteristics of porosity, low permeability, strong heterogeneity and many interlayer. The main challenge of unconsolidated sandstone formation is sand production of oil wells, and the more serious situation is high-pressure oil and gas escaping, blowout accidents, environmental pollution and the safety of operators. In order to solve the sensitivity problem of loose sandstone, a low density admixture was developed: 10.5% artificial floating bead + 4.5% power plant floating bead + 35% micro silicon + 30% fly ash + 20% slag. The particle size distribution of single lightweight material is narrow, and the effect of reducing density is not significant. The developed low-density mixing material has wide and uniform particle size distribution, and can reduce the density of cement slurry to the maximum within the minimum dosage. The new low density admixture cement slurry with adjustable density in the range of 1.4 ∼ 1.7 g / cm3 has good rheological property, short thickening time, water loss less than 50 ml, 24 h compressive strength more than 12 MPa, which can meet the needs of site construction. The temperature and pressure test results show that the system has a wide range of temperature and pressure applications and stable performance. Compared with the similar low density cement slurry, it is about 40% lower than the market price and suitable for commercial application.
Analysis on the hot deformation flow stress curves of novel 6082 aluminium alloys with Mn addition
Authors: Li Yong , Qian Xiaoming , Zhang Yu , Wang Zhaodong , Li Jiadong
Published: April 2021

Two types of 6082 alloy, base alloy free of Mn and novel 0.75Mn alloy with an addition of 0.75% Mn, were prepared. A heat treatment of 450 °C for 6 h was performed, during which large numbers of α-Al (Fe, Mn) Si dispersoids precipitated in 0.75Mn alloy. Uniaxial compression tests were carried out and a series of flow stress curves were obtained at temperature range of 400-550 °C and at strain rate range of 0.001s-1-1s-1. The results revealed an impressive difference between the flow stress curves of base and 0.75Mn alloy that after the yield plateau, the flow stresses of base alloy remained fairly steady at certain levels while the flow stress in 0.75Mn alloy decreased along with strain until the end of deformation. The reason for the decrease of flow stress in 0.75Mn alloy was neither the dissolution of dispersoids nor the dynamic recrystallization. The decrease of flow stress was attributed to the loss of Mn solid solution strengthening effect based on the Mn diffusion rate-controlling mechanism and “pipe diffusion”.
Chemistry at graphene edges in the electron microscope
Authors: Leuthner Gregor T , Susi Toma , Mangler Clemens , Meyer Jannik C , Kotakoski Jani
Published: April 2021

Transmission electron microscopy (TEM) and scanning TEM (STEM) are indispensable tools for materials characterization. However, during a typical (S)TEM experiment, the sample is subject to a number of effects that can change its atomic structure. Of these, perhaps the least discussed are chemical modifications due to the non-ideal vacuum around the sample. With single-layer graphene, we show that even at relatively low pressures typical for many instruments, these processes can have a significant impact on the sample structure. For example, pore growth becomes up to two orders of magnitude faster at a pressure of ca. 10−6 mbar as compared to ultra-high vacuum (UHV; 10−10 mbar). Even more remarkably, the presence of oxygen at the sample also changes the observed atomic structure: When imaged in UHV, nearly 90% of the identifiable graphene edge configurations have the armchair structure, whereas armchair and zigzag structures are nearly equally likely to occur when the oxygen partial pressure in the column is higher. Our results both bring attention to the role of the often neglected vacuum composition of the microscope column, and show that control over it can allow atomic-scale tailoring of the specimen structure.
Pathways Through Which Health Literacy Is Linked to Parental Oral Health Behavior in an American Indian Tribe
Authors: Brega Angela G , Johnson Rachel L , Schmiege Sarah J , Wilson Anne R , Jiang Luohua , Albino Judith
Published: April 2021

Background

Health literacy (HL) is the “ability to find, understand, evaluate and put information to use to improve decision making and, ultimately, improve health and quality of life.” Parents with limited HL are less likely to follow recommended parental oral health behaviors.

Purpose

We tested a theoretical framework designed to clarify mechanisms through which HL may influence parental oral health behavior. The framework proposed that HL: (a) has a direct effect on parental oral health knowledge, beliefs (i.e. self-efficacy; perceived susceptibility, severity, benefits, barriers), and behavior; (b) influences beliefs indirectly through knowledge; and (c) influences behavior indirectly through knowledge and beliefs.

Methods

We analyzed cross-sectional data from a randomized controlled trial designed to reduce dental decay in American Indian children (N = 521). Parents completed survey questions assessing sociodemographic characteristics, HL, and parental oral health knowledge, beliefs, and behavior. Path analysis was used to test the framework.

Results

HL exerted significant direct effects on knowledge and beliefs but not behavior. HL had significant indirect effects on all beliefs through knowledge. Significant indirect effects of HL on behavior occurred through self-efficacy (estimate: 0.99, 95% CI: 0.42, 1.83, p = .005), perceived barriers (estimate: 0.73, 95% CI: 0.29, 1.43, p = .010), knowledge to self-efficacy (estimate: 0.57, 95% CI: .31, 0.98, p = .001), and knowledge to perceived barriers (estimate: 0.24, 95% CI: 0.09, 0.47, p = .012).

Conclusions

HL exerted an indirect effect on parental oral health behavior, with knowledge, self-efficacy, and perceived barriers being the primary constructs linking HL to behavior.
Adherence to Social Distancing Guidelines Throughout the COVID-19 Pandemic: The Roles of Pseudoscientific Beliefs, Trust, Political Party Affiliation, and Risk Perceptions
Authors: Gratz Kim L , Richmond Julia R , Woods Sherry E , Dixon-Gordon Katherine L , Scamaldo Kayla M , Rose Jason P , Tull Matthew T
Published: April 2021

Background

Adherence to COVID-19 social distancing guidelines varies across individuals.

Purpose

This study examined the relations of pseudoscientific and just world beliefs, generalized and institutional trust, and political party affiliation to adherence to COVID-19 social distancing guidelines over three months, as well as the explanatory role of COVID-19 risk perceptions in these relations.

Methods

A U.S. nationwide sample of 430 adults (49.8% women; mean age = 40.72) completed a prospective online study, including an initial assessment (between March 27 and April 5, 2020), a 1 month follow-up (between April 27 and May 21, 2020), and a 3 month follow-up (between June 26 and July 15, 2020). We hypothesized that greater pseudoscientific and just world beliefs, lower governmental, institutional, and dispositional trust, and Republican Party affiliation would be associated with lower initial adherence to social distancing and greater reductions in social distancing over time and that COVID-19 risk perceptions would account for significant variance in these relations.

Results

Results revealed unique associations of lower governmental trust, greater COVID-19 pseudoscientific beliefs, and greater trust in the Centers for Disease Control and Prevention (CDC) to lower initial adherence to social distancing. Whereas greater COVID-19 risk perceptions and CDC trust were associated with less steep declines in social distancing over time, both Republican (vs. Democratic) Party affiliation and greater COVID-19 pseudoscientific beliefs were associated with steeper declines in social distancing over time (relations accounted for by lower COVID-19 risk perceptions).

Conclusions

Results highlight the utility of public health interventions aimed at improving scientific literacy and emphasizing bipartisan support for social distancing guidelines.
Discussion of ‘Event history and topological data analysis’
Authors: Bubenik Peter
Published: April 2021

Garside et al. (2021) use event history methods to analyse topological data. We provide additional background on persistent homology to contrast the hazard estimators used in Garside et al. (2021) with standard approaches in topological data analysis. In particular, Garside et al.’s approach is a local method, which has advantages and disadvantages, whereas homology is global. We also provide more details on persistence landscapes and show how a more complete use of this statistic improves its performance.
P3 A closed loop audit on pre-operative anaemia in major elective orthopaedic surgery
Authors: Koh Chan Hee , Gruner-Hegge Nicolai , Ignatov Dancho , Shakir Aneesul
Published: April 2021

Introduction

The international consensus statement on perioperative management of anaemia advises that patients with haemoglobin (Hb) <130 be treated before undergoing elective operations. The advantages include reduced risk of acute kidney injuries, infections and transfusions, and quicker recovery.

Methods

Data was collected prospectively from 127 consecutive patients undergoing elective arthroplasties at Hinchingbrooke hospital. Baseline compliance with the consensus statement was first assessed in May 2018, and the results presented at a clinical governance meeting. Departmental action plans included early identification of anaemia and treatment to Hb 130, delaying operations where necessary. We then reassessed compliance in May 2019.

Results

There was a statistically significant change in practice (p = 0.036). The proportion of patients undergoing arthroplasties despite Hb < 130 reduced from 38% to 21%. Those operated with Hb < 120 decreased from 14% to 0%. The proportion of preoperative anaemias that were appropriately investigated during preoperative assessment increased from 11% to 80% (p < 0.001). The increase in attempted treatment of preoperative anaemia prior to surgery however was not significant (7% vs 20%; p = 0.279).

Discussion

Implementation of departmental action plans resulted in substantial improvements to clinical practice. For those that underwent arthroplasties despite mild preoperative anaemia, it may have been felt that delays in improvement to quality of life for treatment may be unacceptable, or the causes (e.g. chronic disease) difficult to treat. Further action plans should involve even earlier identification of anaemia, involving primary care at the point of referral.
P6 A proforma to improve the acute management of traumatic anterior shoulder dislocations to meet published national standards for treatment
Authors: Donovan Richard L , Abdelmalek Amir , Crowther Mark A A , Packham Iain
Published: April 2021

Background

BESS/BOA Patient Care Pathways provide national guidelines for the acute management of traumatic anterior shoulder dislocations with respect to emergency reduction and follow-up assessment. COVID-19 posed increased challenges in terms of analgesia choice and altered follow-up arrangements. This study aimed to assess adherence to the care pathway and improve patient care.

Methodology

We retrospectively analysed all acute traumatic anterior shoulder dislocations at the MTC in Bristol. We collected data during 01/04/2019-31/05/2019 and 01/04/2020-31/05/2020 to analyse the quality of their management. Data parameters collated included examinations and imaging performance, choice of analgesia, follow-up rates, and physiotherapy referrals.

Results

We identified 32 patients in 2019, and 24 in 2020. Full neurovascular examinations pre- and post-reduction were poorly documented. Peri-reduction imaging utilization was near 100%. Referral to follow-up was 88% in 2019 but 38% in 2020. Of those assessed in clinic during COVID-19, fewer were mobilised early or referred to outpatient physiotherapy.

Conclusions

We have created a proforma/prompt to improve the quality of the management of these injuries, and successfully liaised with the Emergency Department for this to be included in their documentation. This proforma improves documentation quality, access to follow up and physiotherapy. During a ‘second wave’ we encourage patient access to BESS online resources.
P7 A review of the understanding and use of the Regional Liver Trauma Guidelines
Authors: Thakkar Rohan , Ammar Khaled , Meredith Ellen , Jones Michael ,   Northern Surgical Trainees Research Association
Published: April 2021

Introduction

The liver is the most commonly injured intra-abdominal organ and occurs in 30% of patients undergoing laparotomy for penetrating injuries and in 15–20% of laparotomies for blunt injuries. CT scan is the investigation of choice for accurate diagnosis and categorization of hepatic injury. Management of isolated liver trauma can be by operative or non-operative management, guided mainly by haemodynamic stability of the patient irrespective to category of injury. Close observation of patients undergoing non-operative management is important; they may develop early complications that require operative intervention, including bleeding, bile leak and peritonitis.

Methods

A questionnaire will be sent to the General Surgery consultants and registrars within the North East of England, a region with eleven hospitals taking General Surgical admissions, two of which are regional trauma centres. This is to assess the understanding of liver trauma classification and management and their familiarity with and adherence to the regional liver trauma guidelines. Following this, the guidelines will be distributed throughout the region with accompanying teaching sessions. A follow up questionnaire will determine the improvement of regional knowledge and use of the guidelines. In parallel, the outcome of liver trauma patients within the region will be sought to look for correlation between the education and the patient’s outcome.

Results

Regional distribution of the results will demonstrate the change in the education of liver trauma management and the subsequent change in patient’s outcome. Results will be recorded using Excel and analysed using SPSS statistical software.