bluuebunny/crossref_metadata_2025 huggingface dataset:
Variáveis biomecânicas dos membros inferiores são indicadores do padrão de apresentação da tendinopatia patelar em atletas de elite africanos de basquetebol e voleibol
Authors: Aiyegbusi Ayoola , Tella Bidemi , Okeke Chukwuebuka
Published: September 2019

Objetivo Este estudo determinou o padrão de apresentação e gravidade da tendinopatia patelar (TP) e sua relação com variáveis biomecânicas selecionadas em atletas de elite.

Métodos O estudo envolveu 98 jogadores de elite nigerianos de basquetebol e voleibol com idades entre 18 e 35 anos. Testes clínicos e ultrassonografia foram usados para separar os participantes em grupos sintomáticos e assintomáticos. Procedimentos padrão foram utilizados para avaliar o ângulo do quadríceps (ângulo Q), a torção da tíbia, a dorsiflexão do tornozelo, a flexibilidade dos isquiotibiais, e a postura do pé. Usou-se o questionário Victorian Institute of Sport Assessment Questionnaire, Patellar Tendon (VISA-P) para avaliar a gravidade dos sintomas nos grupos sintomáticos. A análise estatística foi realizada por meio de análise de variância (ANOVA, na sigla em inglês), análise post hoc, e correlação de Pearson, com nível de significância estabelecido em p < 0,05.

Resultados Pontuações significativamente menores de sentar e alcançar (p = 0,01), aumento da pontuação do índice de postura do pé (p = 0,01), e redução da amplitude de dorsiflexão do tornozelo (p = 0,03) foram encontrados em participantes de ambos os sexos com TP sintomática. Ângulos Q (p = 0,02) maiores nos homens e ângulos de torção tibial maiores (p = 0,001) nas mulheres também foram encontrados nos grupos de TP sintomática. A gravidade dos sintomas foi significativamente maior no grupo que tinha apenas sintomas clínicos (p = 0,042), e estava significativamente correlacionada com a flexibilidade dos isquiotibiais tanto nos homens (r = -0,618) quanto nas mulheres (r = -0,664).

Conclusão A redução da flexibilidade dos isquiotibiais, o aumento da pronação do pé, e a redução da amplitude de dorsiflexão do tornozelo foram significativos em participantes com TP sintomática.
Effect of Dentin Pretreatment with Arginine on Microshear Bond Strength of Etch-and-Rinse or Self-Etch Adhesive Systems
Authors: Borgo Gabriela Oliveira , Vieira-Junior Waldemir Francisco , Theobaldo Jéssica Dias , Aguiar Flávio Henrique Baggio , Lima Débora Alves Nunes Leite
Published: September 2019

Objective The main purpose of this study was to evaluate the effect of dentin pretreatment with 8% arginine on the immediate and 6-month bond strength (BS) of adhesive systems and surface morphology of dentin.

Materials and Methods Dentin bovine specimens (5 × 5 mm) were allocated into following pretreatments: without pretreatment (conventional technique, C) or exposure to arginine solution (A) for 5 minutes prior to tooth restoration. The adhesive procedure was performed using (n = 12): 3-step etch-and-rinse adhesive (Scotchbond Multipurpose—SBMP [C+SBMP and A+SBMP]); 2-step etch-and-rinse adhesive (Single Bond 2 - SB [C+SB and A+SB]); or 2-step self-etch adhesive (Clearfil SE Bond - CSEB [C+CSEB and A+CSEB]). After 24 hours, the composite resin restorations were evaluated immediately and after 6 months of water storage using a microshear test and fracture pattern. The dentin surface exposed to A was assessed by scanning electron microscopy (SEM). The immediate BS data were submitted to a two-way analysis of variance and Tukey's test, and the long-term BS results were analyzed using Kruskal–Wallis and Dunn tests (α = 0.05).

Results There was a significant decrease in immediate and 6-month BS for the A+SB and A+CSEB groups, which differed statistically from the C group. The fracture pattern was predominantly adhesive for SB and CSEB adhesive for C and A. The SEM images presented a different conditioning pattern of the dentin exposed to A.

Conclusion The dentin pretreatment with arginine interfered negatively in the immediate and long-term BS of the simplified adhesive system. However, the SBMP adhesive was not affected by arginine pretreatment presenting the most satisfactory results.
The Versatility of the Superficial Circumflex Iliac Artery Perforator Flap: A Single Surgeon's 16-Year Experience for Limb Reconstruction and a Systematic Review
Authors: Berner Juan Enrique , Nikkhah Dariush , Zhao Jade , Prousskaia Elena , Teo Tiew Chong
Published: September 2019

Background The superficial circumflex iliac artery perforator (SCIP) flap is a versatile option of free tissue transfer for small to large defects. In this study, we examine the advantages of the SCIP flap, its cadaveric anatomy, and clinical subtypes.

Methods Ten cadavers were dissected and the corresponding pedicles of the SCIP and groin flaps were identified. A retrospective review of 20 clinical cases of free SCIP flap reconstruction was undertaken. The indication for reconstruction, flap dimensions, and survival were analyzed. A systematic literature review was conducted including articles that have previously reported the use of the SCIP flap.

Results The SCIP pedicle was present in all our cadaveric dissections. The starting point of its pedicle ranged from 1.5 to 4.5 cm along the superficial circumflex iliac artery. The median diameter of the perforator and its concomitant vein was 1mm (range 0.8–2 mm). A cutaneous vein (1.3–2.3 mm) could be included in the flap if the concomitant vein was too small. Twenty consecutive patients had free SCIP flaps between 2002 and 2018. The indications were for finger defects (n = 8), thumb reconstruction (n = 1), lower limb compound fractures (n = 3), iatrogenic wounds (n = 2), upper limb large defects (n = 2), and scar contractures (n = 4). Flap dimensions ranged from 2 × 4 cm to 14 × 25cm, and the longest pedicle was 8cm. All flaps survived. The systematic literature review identified 34 previous reports using the SCIP flaps, most of these published by Asian units.

Conclusion The SCIP flap is useful for reconstruction throughout the body due to its ease of dissection, thinness, adjustable pedicle length, and flap dimension ranging from tiny to large, as well as the feasibility of raising a compound flap incorporating an adipofascial or vascularized bone component if necessary.

This is a level of evidence therapeutic IV study.
Health Care Utilization and Payer Cost Analysis of Robotic Arm Assisted Total Knee Arthroplasty at 30, 60, and 90 Days
Authors: Mont Michael A. , Cool Christina , Gregory David , Coppolecchia Andrea , Sodhi Nipun , Jacofsky David J.
Published: September 2019

This study performed a health care utilization analysis between robotic arm assisted total knee arthroplasty (rTKA) and manual total knee arthroplasty (mTKA) techniques. Specifically, we compared (1) index costs and (2) discharge dispositions, as well as (3) 30-day (4) 60-day, and (5) 90-day (a) episode-of-care costs, (b) postoperative health care utilization, and (c) readmissions. The 100% Medicare Standard Analytical Files were used for rTKAs and mTKAs performed between January 1, 2016, and March 31, 2017. Based on strict inclusion–exclusion criteria and 1:5 propensity score matching, 519 rTKA and 2,595 mTKA patients were analyzed. Total episode payments, health care utilization, and readmissions, at 30-, 60-, and 90-day time points were compared using generalized linear model, binomial regression, log link, Mann–Whitney, and Pearson's chi-square tests. The rTKA versus mTKA cohort average total episode payment was US$17,768 versus US$19,899 (p < 0.0001) at 30 days, US$18,174 versus US$20,492 (p < 0.0001) at 60 days, and US$18,568 versus US$20,960 (p < 0.0001) at 90 days. At 30 days, 47% fewer rTKA patients utilized skilled nursing facility (SNF) services (13.5 vs. 25.4%; p < 0.0001) and had lower SNF costs at 30 days (US$6,416 vs. US$7,732; p = 0.0040), 60 days (US$6,678 vs. US$7,901, p = 0.0072), and 90 days (US$7,201 vs. US$7,947, p = 0.0230). rTKA patients also utilized fewer home health visits and costs at each time point (p < 0.05). Additionally, 31.3% fewer rTKA patients utilized emergency room services at 30 days postoperatively and had 90-day readmissions (5.20 vs. 7.75%; p = 0.0423). rTKA is associated with lower 30-, 60-, and 90-day postoperative costs and health care utilization. These results are of marked importance given the emphasis to contain and reduce health care costs and provide initial economic insights into rTKA with promising results.
Sobolev-orthogonal systems of functions and some of their applications
Authors: Sharapudinov I. I.
Published: September 2019

Systems of functions are considered which are associated with a given orthogonal system and are orthogonal with respect to an inner product of Sobolev type involving terms with masses concentrated at a point. Special attention is paid to such systems generated by classical orthogonal systems such as the cosine system, the Haar system, and the systems of Legendre, Jacobi, and Laguerre polynomials. The approximation properties of Fourier series in Sobolev-orthogonal systems are investigated in several cases. For (generally speaking, non-linear) systems of differential equations deep connections between Sobolev-orthogonal systems and the Cauchy problem are considered.

Bibliography: 54 titles.
Metabarcoding demonstrates dietary niche partitioning in two coexisting blackfish species
Authors: Rees Gavin N. , Shackleton Michael E. , Watson Garth O. , Dwyer Georgia K. , Stoffels Rick J.
Published: September 2019

A problem for fisheries ecologists who carry out dietary analysis on their specimens is dealing with contents that are difficult to identify, particularly when the contents comprise digested prey. We used a DNA metabarcoding approach to determine the diets of two co-occurring black fish species (Gadopsis bispinosus and Gadopsis marmoratus) to circumvent any issues with trying to apply microscopic methods to identify diets. We examined the frequency of occurrence of taxa across all specimens and the proportion that taxa contributed to total diet. In this way we hoped to demonstrate that a DNA-based method could resolve dietary differences of coexisting taxa. We showed that 10 macroinvertebrate taxa dominated the diets of both species and, of these, 7 occurred in all specimens of both taxa, indicating they were an important component of the diet of both species. Twelve taxa were present only in the G. bispinosus diet and four of those were terrestrial invertebrates; six taxa were found only in G. marmoratus. Our DNA-based approach to examine the taxa in the guts of two co-existing Gadopsis species provided sufficient resolution to show a significant degree of dietary partitioning.
Exploring nurse navigators' contribution to integrated care: a qualitative study
Authors: Hannan-Jones Clare , Young Charlotte , Mitchell Geoffrey , Mutch Allyson
Published: September 2019

This paper examines nurse navigation as a model of integrated care operating across primary and secondary healthcare settings. A two-phase qualitative study involving a focus group with seven nurse navigators (NNs) to explore their understandings and perceptions of the role, followed by in-depth interviews with three NNs to examine current practice, was undertaken in Queensland, Australia. NNs’ role spanned a continuum of patient and population care, and involved engagement in clinical integration, coordinating patient care and providing education and points-of-contact for healthcare professionals. NNs also engaged in professional integration, fostering interdisciplinary collaboration, education and connections between healthcare professionals, while promoting integrated care across care settings. NNs were enabled through the establishment of relationships, trust and shared communication between stakeholders. NNs’ work transcended traditional clinical boundaries, operating horizontally across silos and specialties, which allowed them to avoid (some) system shortfalls. By contributing to a culture of integration, NNs can potentially support more sustainable integrated care practices that extend relationships between healthcare professionals and beyond individual patients. Increasing our understanding of nurse navigation as a model of integrated care, this study illustrates the complexity, diversity and breadth of the role and its ability to contribute to broader, system-wide integration.
La grammaire italienne de Lodewijk Meijer (1672)
Authors: Szoc Sara , Swiggers Pierre
Published: September 2019

En 1672 parut à Amsterdam, chez Abraham Wolfgang (1634–1694), une grammaire de l’italien rédigée en néerlandais. L’auteur de cette grammaire, publiée anonymement, peut être identifié comme Lodewijk Meijer (1629–1681). L’ouvrage, intituléItaliaansche Spraakkonst, se caractérise par une organisation méthodique très explicite, qui se reflète dans la structuration rigide et systématique de la matière, dans l’emploi conséquent d’une terminologie bilingue (latin–néerlandais), dans la description, fort parallèle, des classes de mots, et dans l’application rigoureuse du principe de conformité structurelle (analogiaen latin;gelijkvormigheidten néerlandais). Construite sur une théorie de grammaire générale, l’Italiaansche Spraakkonstest une grammaire particulière de l’italien qui, tout en étant basée sur des sources livresques, fournit une description très complète et didactiquement adéquate. Le noyau de la grammaire est constitué par la description des classes de mots: celles-ci sont définies et décrites selon leur nature, leur sous-classification (formelle et sémantique) et leurs possibilités de combinaison. La théorie des parties du discours dans l’Italiaansche Spraakkonstest organisée autour du nom et du verbe, les deux classes de mots par rapport auxquelles les autres classes sont définies. La présente étude s’ouvre par une mise en contexte historiographique de la grammaire italienne de L. Meijer. Ensuite, la démarche méthodologique et la terminologie déployées dans l’ouvrage sont au centre de l’analyse. L’examen de l’organisation de la matière grammaticale procède de l’articulation globale des classes de mots à l’étude de deux classes, à savoir l’article et l’adnomen(néerlandais:bynaam), ce dernier terme désignant chez Meijer l’ensemble des éléments adjectivaux. Le fait d’avoir érigé lesadnominaen une classe de mots autonome constitue un des apports les plus remarquables de ce grammairien, philosophe et ami de Spinoza (1632–1677), qui s’inscrit dans le courant du rationalisme post-cartésien.
Spotlights on the notion of lexical motivation across languages in the Western linguistic tradition, from the 16th century to the present
Authors: Urban Matthias
Published: September 2019

This article shows that an interest in differences and similarities in patterns of lexical motivation across languages has a long, if discontinuous, history in Western linguistic thought. The aim of the article is to trace this history by presenting examples that highlight the enduring fascination of authors from very different traditions with recurrent patterns of lexico-semantic associations. It also discusses the significance attributed to these patterns, which ranges from their practical value in etymological research to proving the psychic unity of mankind.
The transformation of African–Russian economic relations in the multipolar world-system
Authors: Gerőcs Tamás
Published: September 2019

Despite the historical legacy of the Soviet Union, the Russian Federation’s economic presence in Africa today is minuscule in comparison to that of the West or China. The aim of this Briefing is to provide a framework for the trajectory of African–Russian economic ties in the changing international environment. Although the economic, trade and investment affairs could develop more complementarity, it is still an open question whether African countries benefit from the deepening economic ties or whether these inhibit local socio-economic development.
Key comparison BIPM.RI(I)-K1 of the air-kerma standards of the NPL, United Kingdom and the BIPM in 60Co gamma radiation
Authors: Kessler C , Burns D , Kelly M , Maughan D J , Bass G A , Homer M J
Published: September 2019

A key comparison of the standards for air kerma of the National Physical Laboratory (NPL), United Kingdom and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 60Co radiation beam of the BIPM in November 2017. The comparison result, based on the calibration coefficients for two transfer chambers and expressed as a ratio of the NPL and the BIPM standards for air kerma, is 0.9996 with a combined standard uncertainty of 3.0×10-3. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database.

KEY WORDS FOR SEARCH

Radiation dosimetry, air kerma, key comparison, Co-60 gamma radiation

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
CCQM-K147 Comparison of value-assigned CRMs for niacin (vitamin B3) in milk powder and infant formula matrices
Authors: Arzate C M Salazar , Burdette C Q , Aragón H Gasca , Lippa K A , Osuna M Arce , Contreras L Regalado , Lee J , Lee S , Baek S -Y , Kim B , Huang T , Guo Z , Li H M , Zhang Q H , Phillips M M , Toman B , Duewer D L
Published: September 2019

The 2017 CCQM-K147 "Comparison of value-assigned CRMs for niacin (vitamin B3) in milk powder and infant formula matrices" is the first Key Comparison directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs) through certified reference materials (CRMs). CRMs certified for vitamin B3 (as niacin or niacinamide) content in milk powder and infant formula matrices were compared using measurements made on these materials under repeatability conditions. Five NMIs/DIs submitted seven CRMs certified for niacinamide and two CRMs certified for niacin. These materials represent most of the higher-order reference materials available in 2017 for this important nutrimental measurand.

Generalized Gauss Markov Regression (GGMR) and Bayesian methods were used to establish the Key Comparison Reference Function (KCRF) relating the CRM certified values to the repeatability measurements. The niacinamide and niacin results for all nine CRMs were deemed equivalent at the 95 % level of confidence and were used to define the KCRF for vitamin B3 (as niacinamide).

Monte Carlo methods and Bayesian methods were used to estimate 95 % level-of-confidence coverage intervals for the relative degrees of equivalence of materials, %d ± U95 (%d), and of the participating NMIs/DIs, %D ± U95 (%D). The Bayesian method estimates were selected as the final DoE values. For the niacinamide and niacin materials, all of the %D ± U95(%D) intervals, were within (-10 to 10) % of the consensus results and all of these are statistically equivalent. These results demonstrate that the participating institutions can value-assign CRMs for niacinamide and/or niacin in milk powder and infant formula matrices.

KEY WORDS FOR SEARCH

Niacin, Niacinamide, milk, infant formula, CRMs

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Photoluminescence properties of blue and green multiple InGaN/GaN quantum wells*
Authors: Li Chang-Fu , Shi Kai-Ju , Xu Ming-Sheng , Xu Xian-Gang , Ji Zi-Wu
Published: September 2019

The photoluminescence (PL) properties of blue multiple InGaN/GaN quantum well (BMQW) and green multiple InGaN/GaN quantum well (GMQW) formed on a single sapphire substrate are investigated. The results indicate that the peak energy of GMQW-related emission (P
G) exhibits more significant “S-shaped” dependence on temperature than that of BMQW-related emission (P
B), and the excitation power-dependent carrier-scattering effect is observed only in the P
G emission; the excitation power-dependent total blue-shift (narrowing) of peak position (line-width) for the P
G emission is more significant than that for the P
B emission; the GMQW shows a lower internal quantum efficiency than the BMQW. All of these results can be attributed to the fact that the GMQW has higher indium content than the BMQW due to its lower growth temperature and late growth, and the higher indium content in the GMQW induces a more significant compositional fluctuation, a stronger quantum confined Stark effect, and more non-radiative centers.
Low channel count montages using sensor tying for VEP-based BCI
Authors: Ahmadi S , Borhanazad M , Tump D , Farquhar J , Desain P
Published: September 2019

Objective. Brain computer interfaces (BCIs) are slowly making their appearance on the consumer market, accompanied by a higher popularity among the general public. This new group of users requires easy-to-use headsets with robustness to non-precise placement. In this paper, an optimized fixed montage EEG headset for VEP BCIs is proposed. Approach. The proposed layout covers only the most relevant area with large sensors to account for slight misplacement. To obtain large sensors, without having them physically available, we tie multiple sensors together and simulate the effect by averaging the signal of multiple sensors. Main results. In simulations based on recorded 256-channel EEG data, it is shown that a circular center-surround configuration with sensor tying, leading to only eight channels covering a large part of the occipital lobe, can provide high performance and good robustness to misplacement. Automatically optimized layouts were unable to achieve better performance, demonstrating the utility of this manual design. Finally, the performance and benefits of sensor tying in the manual design are then validated in a physical experiment. Significance. The resulting proposed layout fulfills most requirements of an easy to use consumer EEG headset.
Application of solar energy technology in the field of new energy vehicles in China
Authors: Song Yingye , Zhang Shaoguo
Published: September 2019

This paper analyzes the development status of solar cars and the main application of solar energy in the field of new energy vehicles. Solar energy application in the field of new energy vehicles there are two main ways: first, as a driving force of the car; Second, as an auxiliary energy for cars.
Container built-in loading and unloading device design
Authors: Xie Ruibo , Li Jin , Ye Lei , Huang Caowei
Published: September 2019

Aiming at the problem of low efficiency of logistics loading and unloading tools at the present stage, in this paper, a container loading and unloading device with minimal container volume ratio is designed. The mechanical model of each part of the device is established, the local parameters of the device are designed by MATLAB software, and the device is simulated and verified by ANSYS software. The results show that the design of the device is reasonable. Under the working condition of ultimate load 577.98 kg, the telescopic arm is allowed to extend 1 m outward to the container, the range of transverse movement in the container is 1.55 m, and the range of longitudinal movement is 4.36 m, which meets the design requirements of rigidity and strength, and accounts for only 7.34% of the volume of the container, it can meet the requirement of on board.
Analysis on electric corrosion government of generator stator bar in the near Wake Island Hydropower Station
Authors: Tan Picheng , Chen Mingzhao , Zheng Yuan
Published: September 2019

In view of generator stator bar corrosion problems in the near Wake Island Hydropower Station, performed causal analysis and technical innovation. The effect of cleaning and repairing measures were analyzed and verified. In view of the security hidden danger still exist after processing, put forward the stator bar transformation ideas and carried it on. The reconstruction effect was test verification as well. The results of the study can provide reference for power plant generator to handle similar stator bar corrosion problems.
Electromagnetic ultrasonic measurement for welding residual stress detection - comparison between experiment with numerical simulation
Authors: Wang Hong , Feng Jiajun , Shi Shike , Ouyang Linting , Xu Feng , Chen Zhiping , He Yan , Li Guoli
Published: September 2019

In order to study the feasibility of electromagnetic ultrasonic method on the welding residual stress detection in Q345R plate, experiments and numerical simulations were carried out. The welding residual stress in the plate was firstly measured by electromagnetic acoustic transducer (EMAT). Then, finite element model of welding process was established to predict the residual stress in plate, who’s rationality was verified by blind hole experiment. At last, the average of numerical simulation results at five points along the plate’s thickness direction was compared with the electromagnetic ultrasonic measurement results. The results show that the residual stress measured by EMAT is consistent with those from numerical simulation in direction of the weld. However, in the vertical direction of the weld, the deviation between EMAT results and numerical simulation is relatively large near the weld fusion line. This phenomenon is also found in the junction between the heat affected zone and the base metal.
Simulation of Pull-in mechanism of plate actuator considering damping
Authors: Liu Xin , Fang Yuming , Zhang Wenxu , Man Wenwen , Ji Lili
Published: September 2019

Based on electrostatic micro-actuator, energy method is used to analyses its static and dynamic Pull-in mechanism. In addition, the model of electrostatic micro-actuator perforated-plate is used for example analysis to derive its dynamic Pull-in parameter without and with considering squeeze damping effect. By comparing the parameter values from MATLAB calculation and ANSYS simulation under the two circumstances mentioned above, the effects of damping ratio on Pull-in parameter can be obtained. The results show that, the dynamic Pull-in displacement is more than the static Pull-in displacement. And with the existence of squeeze damping effect, Pull-in voltage will increase. When the damping ratio reaches a certain extent, the dynamic Pull-in voltage value will be as large as the static Pull-in voltage value.
The design of dis-assembly and assembly vehicle for outdoor high voltage pillar insulator of substation
Authors: Tang Xiaolong , Meng Lijun
Published: September 2019

The overhaul of outdoor pillar insulators in substations plays an important role in the safe operation of the whole substation, ensuring the safety of power consumption and reducing economic losses. Because of its unique layout and special environment, the existing disassembly and assembly work is usually carried out by pure manual work. For this reason, this paper puts forward a design of disassembly and assembly vehicle specially for insulator disassembly and assembly, which can automatically realize disassembly, assembly and transportation and greatly improve the efficiency of operation. This paper mainly focuses on the design of its hydraulic system.
Modeling and simulation of two port proportional slip-in cartridge valve based on AMESim
Authors: Wang Wenzhu , Wu Rendong , Yuan Chaolong , Chang Baohua , Du Dong
Published: September 2019

Two port proportional slip-in cartridge valves are critical components of the heavy duty press hydraulic system. Their performance, especially the static flow rate under different valve opening size and the valve response time, is important to the press velocity control precision. So, it is necessary to build an accurate model of the valve to analyse different parameters’ influences on the valve performance. Based on the analysis of the valve structure and working principle, the valve model is established by the AMESim. The valve flow rate under different valve opening size ratio is calculated using the simulation model. The rated flow rate calculated by the simulation model is 0.33% less than the sample value, and the variation trend of the calculated flow rate curve is consistent with the manual curve. This demonstrates the considerable effectiveness of the valve simulation model. Then, the influences of the spring stiffness, the pilot oil pressure and the pilot valve gain on the valve poppet response time are analysed using the simulation model, respectively. This research may offer the basis for the whole hydraulic system building and control strategy designing.
Design and adsorption force optimization analysis of TOFD-based weld inspection robot
Authors: Zhang Yihui , Dai Zhiyong , Xu Yingqiu , Qian Ruiming
Published: September 2019

To meet the requirements of large metal tank weld inspection, a robot design scheme was proposed to walk on the outer surface of the tank and carry TOFD probe. The wall-climbing module, connecting frame module and TOFD weld inspection module are specifically designed. In this paper, the permanent magnetic adsorption principle and four-wheeled mechanism are both adopted in the wall-climbing module, meanwhile, the magnetic wheel’s adsorption force is analyzed under multiple parameters. The main parameters affecting the adsorption force are obtained. To ensure the minimum size and the lightest quality of magnetic wheel, the adsorption force is also optimized based on the main parameters which are related to the permanent magnet itself. The above work provides a reference value for the research and development of intelligent weld inspection products of large metal tanks.
Numerical simulation of NO emission characteristics of a high-speed and high-temperature heat-airflow test system
Authors: Cai Chaozhi , Guo Lubin , Liu Jiachen , Wei Zhenyu
Published: September 2019

In this paper, the distributed parameter calculation model of the combustor of the high-speed and high-temperature heat-airflow test system is presented. The three-dimensional geometric model of combustor is established by using commercial software ANSYS 15.0, and the grids are divided. In order to understand the NO emission characteristics of the combustor of the high-speed and high-temperature heat-airflow test system, the combustion of fuel in the combustor is simulated by using the computational fluid dynamics simulation module of ANSYS 15.0. The simulation results show that the combustor produces the most thermodynamic NO near the theoretical oil-gas ratio, but less thermodynamic NO when the air is insufficient or excessive. Therefore, in order to effectively control the production of thermodynamic NO, it should be considered from lean or rich oil combustion.
Damage identification of wind turbine blade based on dynamic characteristics
Authors: Gu Yongqiang , Feng Jinfei , Jia Baohua
Published: September 2019

The wind turbine blade is an elongated structure composed of composite materials. Due to the harsh working environment and the vibration and deformation during operation, the blade is easily damaged, which seriously affects the smooth operation of the wind turbine, and has great potential safety hazards. The finite element software ANSYS is used to study the vibration characteristics under the condition of blade rotation, and different damage modal analysis can be carried out for different positions. The BP neural network is established by MATLAB to quantify the damage degree of the blade. The analysis results show that the damage and damage degree can be recognized by the change of natural frequency before and after the damage of the blade. The damage location can be identified by change rate of strain mode before and after the damage of the blade. The damage degree of the blade can be quantified and judged. The relative error rate is between -4.36% to 2.73%, and the recognition effect is more accurate.
Research and design of live maintenance robot for substation equipment
Authors: Li Jinbin , Zhang Yaodong , Wang Tao , Chen Jun
Published: September 2019

This paper focuses on the reform of the live working mode in substation and the urgent need for the development of safe live working equipments. A multi-agent live maintenance automatic robot has been designed. On the basis of satisfying insulation safety protection requirements, it has flexible operation characteristics, and can independently implement typical live maintenance and detection projects for substation equipments. The robot is appropriate for narrow space and complex working conditions with high precision. Through design, manufacturing, simulation test, field application and other methods, the research and prototype development of this live maintenance robot for substation are carried out from the aspects of operational requirements, structural design and key component design.
Study on initial combustion characteristics of kerosene based on inductive charging ignition system
Authors: Wu Hao , Zhang Fujun , Wang Zhengkai , Gao Hongli
Published: September 2019

Spark ignition is an important method to achieve combustion of in-cylinder mixture. The inductive charging ignition is considered to be a simple and effective ignition method. This study presents a circuit simulation model of this ignition system in MATLAB/Simulink and the effects of charging voltage, charging time and multi-pulse charging interval on ignition energy were calculated and the ignition energy value was obtained. The experimental study of the ignition system in a constant volume vessel was carried out to explore the influence of ignition energy on the initial combustion of kerosene. The results show that the simulation results match well with the experimental results. With the increase of ignition energy, the initial flame propagation of kerosene shows speed fluctuations and the higher ignition energy makes the propagation speed of flame fluctuate more obviously.
Experimental research on the precast concrete slab with additional reinforcement at slab end
Authors: Geng Jiao , Liu Kang , Qi Hu , Wang Dongyan
Published: September 2019

In order to study the performance of the precast concrete slab with additional reinforcement at slab end, the vertical monotonic loading test was carried out on four double-span continuous slab specimens. By observing the failures and making a comparison between additional reinforcement end and extended reinforcement end in terms of stiffness and bearing capacity under vertical unidirectional loading, it can be concluded that the bearing capacity of the composite floor slab end with neither protruding rebars nor additional reinforcement is obviously lower, but the additional reinforcement at slab end could evidently enhance the bearing capacity and stiffness, even higher than that of slabs extending rebars into supports.
Application of high-order differential energy operator in bearing fault diagnosis
Authors: Xu Yuanbo , Cai Zongyan , Ding Kai
Published: September 2019

An alternative energy operator demodulation method named high-order differential energy operator is proposed in this paper. The high-order differential energy operator, unlike previous demodulation techniques, can detect the weak fault bearing signature from a heavily contaminated signal because it can increase the signal-to-noise ratio. Furthermore, this energy operator is also able to suppress vibration interferences. Thus, the operator is more robust than the classical Teager energy operator (TEO) and its improved versions (DESA-1 and DESA-2 for short). Besides, it is also a non-parameter and non-filtering method, so it is easy and straightforward to apply. Finally, the built-in amplitude demodulation (AD) capability eliminates the enveloping step required by most AD methods like TEO and Hilbert transform (HT). The results of simulation tests and bearing fault experiments demonstrate that this method can effectively extract fault features, certifying its superiority in comparison with previous demodulation methods. Therefore, it is more likely to be useful and practical in the field of bearing fault diagnosis, especially in the presence of intense noise and interferences.
Noise controlling by means of intensity of acoustic radiation measurements
Authors: Vodola Vincenzo
Published: September 2019

Noise control in working places often involves the design of acoustic treatment of enclosures and the design of proper devices able to reduce vibration of surfaces in machinery and structural borne propagation. However, in order to optimize the efficiency of the treatment, it would be very useful to properly relate the vibration with total sound emission. From a general point of view, it is quite important to determine the relation between vibration surfaces and total sound (or noise) emission. The same problem could be also studied for several other sources, such as loudspeakers or musical instruments. We employ the Intensity of Acoustic Radiation (IAR), a novel, corresponding parameter introduced recently, that relates modal analysis with sound production. This parameter is defined as the space-averaged amplitude of cross-spectrum between sound pressure caused by the movement of the vibrating surface and the velocity of the vibration of the surface itself. To measure IAR, an omnidirectional microphone is placed in a fixed position at a short distance over the surface, while an accelerometer is mounted at the same points utilized during modal analysis. IAR showing a very high correlation between Frequency Response Function (FRF) and sound production of the surfaces is, therefore, able to describe the relationship between vibration and noise emission.
Dynamic characteristics analysis of nonlinear suspension system of automobile with seven degree of freedom
Authors: Jia Hongyu , Yun Chao , Wang Ying
Published: September 2019

The application of MATLAB/SIMULINK to establish the mechanical simulation model of seven-degree-of-freedom vehicle linear and non-linear suspension system. Realization of system response under simulated road excitation, the dynamic characteristics of the non-linear suspension are studied, the non-linear spring and damping are simulated, and the parameter ε is introduced to change the degree of nonlinearity. The root mean square values of acceleration and displacement of linear suspension, non-linear stiffness suspension and non-linear damping suspension are analyzed and compared under different pavement conditions. The results show that: The mean square root of the acceleration of the body mass center and the pitch angle of the non-linear suspension are reduced by 14.3% and 17.0% respectively compared with the linear acceleration of the body mass center and the pitch angle; The root mean square value of pitch acceleration of non-linear suspension damping is 31.2% less than that of linear acceleration, which improves ride comfort and safety to a certain extent.
Heat transfer characteristics in channel with square rib at different Mach numbers
Authors: Li Heng , Wang Duo , Yu Ting , Xu Hongyi
Published: September 2019

The detailed flow structures and closely-related heat transfer characteristics were investigated along the wall of a cooling channel with rib tabulator by computation. The two-dimensional Navier-Stokes equations were solved using the density-based algorithm and strongly-coupled with the heat-transfer equation. Three typical Reynolds numbers defined by rib height and Mach numbers were set at 500, 750, 1000 and at 0.2, 0.3, 0.4, respectively. Results show that, As the Mach numbers changing from 0.2 to 0.4, the local Nusselt numbers increase and the average heat transfer effects are enhanced. Based on the instantaneous field of vortices evolvement, the vortexes are first generated near the top surface of the rib by the strong shear effects. Then the vortexes are shed and intensified gradually downstream. Particularly, an important phenomenon is, for the first time, discovered that the high Nusselt number has a consistent correlation with the positive and negative sign alteration of the shear layer on the wall, which satisfactorily explains the mechanisms of heat transfer enhancement due to the flow.
Obstacle contour extraction method based on improved Grabcut algorithm
Authors: Mao Jiateng , Hu Yueli
Published: September 2019

Obstacle distance measurement has an important role in the design of mobile robots, which allows the robot to timely complete the movement steering to avoid damage caused by crushing. The accurate segmentation and edge detection of the target obstacle in the image is the premise of completing the measurement. In this paper, based on the classification and location of specific obstacles, a method of obstacle segmentation based on improved Grabcut algorithm is proposed, and the edge contour is extracted by Canny operator. The method classifies the image’s background pixels using a Laplacian Mixture Model and modifies the covariance matrix to change the probability density function of that model, thereby reducing the misclassification probability of the pixels. In addition, the method crops the input image in advance to reduce the running time of the algorithm. This paper also introduces a way to initialize the image’s Trimap, considering the visual angle of the sweeper. The above four improvements enable the method to accurately segment obstacle targets and extract contour curves. The accuracy of the method and the good real-time performance on the embedded platform are verified by comparison experiments.
Design of the desktop vapor polisher with acetone vapor absorption mechanism
Authors: Xu Kaiwen , Xi Tao , Liu Chunrong
Published: September 2019

Acrylonitrile butadiene styrene (ABS) parts fabricated by fused deposition modeling (FDM) usually have high surface roughness due to the stair-step effect. The vapor smoothing method gives ABS parts a smooth and shiny appearance. However, the organic solvents used for vapor smoothing such as acetone could be toxic to operators. This paper proposed the design of a desktop vapor polisher with acetone vapor absorption mechanism. It prevents acetone vapor from leaking into the outside environment during the smoothing process in a technically feasible and economical way by using water. The polisher also includes other innovations such as the modular design and induction heating method. The benefits of the design include environmental friendly, economy saving, energy saving and user friendly. Finally, a full-scale model has been made to illustrate the layout of the design, and verification experiments have been done with a miniature prototype.
Design of an application which computes the Bistatic coverage zone for The Republic of Cabo Verde
Authors: Lopes Dias Ricardo Yannick Cabral , Liu Tao
Published: September 2019

The purpose of this paper is to design an application which can compute the bistatic system coverage zone for the archipelago of Cabo Verde, where a specific study of bistatic geometry was made. From its triangular configuration, known as bistatic triangle (transmitter, target, receiver), we obtained the parameters, and subsequently, the equations necessary to obtain the Oval of Cassini that delimits the coverage zone that it guarantees. The direct synchronization method was chosen, and the line of sight between transmitting and receiving antennas was required, permitting us to measure the distances from the transmitter to the target and from the target to the receiver. After obtaining all the theoretical validities, a tool was created, for the user to choose the positions of the antennas. Then, the software will paint the coverage zone with the qualities index required in accordance with the chosen data and technical parameters.
Propagation characters of PD UHF signal in a prefabricated joint of XLPE cable
Authors: Wang Luliang , Yang Xu , Cheng Lin , Fu Fangda , Jiang Yi , Pan Zijun
Published: September 2019

Investigating the propagation characters of UHF partial discharge (PD) signals in cable joint is helpful to the application of UHF method in XLPE PD monitoring. In this paper, a propagation model about UHF signal in a prefabricated joint is constructed. Based on it, it effects of some factors, i.e. longitudinal distance of detection location, lateral location of detection, detecting angle, pulse width, pulse amplitude, the size of metal shield and the thickness of semiconductive layer, on the PD signal propagation are studied. It is found that the signal amplitude decays faster in the joint than that in the body, and the signal intensity is much stronger inside the metal shield than that outside. The maximum amplitude of electromagnetic wave radiated by the PD source appears in the radial direction along the radius of the cross-section. The short duration of discharge pulse contributes to the appearance of high-order modes, while the response signal is proportional to the PD source. The metal shield and semiconductive layer increase the signal attenuation. These results provide insight into some design parameters of UHF antenna and its installation location.
Effect of absorbing materials on shielding effectiveness of incomplete cavity
Authors: Chen Xin , Huang Xuegong
Published: September 2019

With the deterioration of electromagnetic environment, the electronic devices are seriously affected by the electromagnetic interference in high frequency, which makes it especially important to find protective methods. In this paper, a wireless transmission equipment was taken as an example to analyze the effect of absorbing materials on shielding effectiveness of cavity by numerical simulation. The results show that the absorbing performance is little affected by the position of absorber, but greatly affected by the direction. Furthermore, absorbing materials can effectively reduce the electromagnetic coupling of penetrating wire and increase the shielding effectiveness at resonant frequencies, but have little effect on interference transmitted by conduction, which indicates that the absorbing materials is an effective but deficient solution for electromagnetic protection of electronic equipment with complete circuit.
Research on IPMSM position decoupling control without filter
Authors: Li Wu , Chen Jing
Published: September 2019

In this paper, a new method of decoupling sensorless and filterless IPMSM (Interior permanent magnet synchronous motor) high frequency square wave is proposed, which is a new method of decoupling the rotor position of the motor and forming a stable control system by injecting high frequency square wave into the static shafts and computing the signal delay. Due to the high frequency square wave injection method, the influence of rotor resistance is reduced and the estimation accuracy is improved. At the same time, the decoupling method without filter is adopted to avoid filter interference and improve system bandwidth. In this paper, a better observer than PI observer is adopted, so that the system estimation accuracy is higher and the anti-interference performance is stronger. Finally, the simulation is realized by matlab.
Quantifying the harmonic impact for multi-harmonic sources
Authors: Tan Meng , Li Yaqiong , Geng Xiaohong , Wen Jun
Published: September 2019

Accurately dividing the harmonic impact of each harmonic source on the PCC bus is an important prerequisite for implementing the ‘reward and punishment scheme’. At first, the equivalent circuit model of multi-linear load harmonic source in PCC bus is obtained by using circuit theory, and the method of quantifying the harmonic impact for multi-harmonic sources is derived. Secondly, the M-estimated robust regression method is introduced into quantifying the harmonic impact for multi-harmonic sources. The method uses the iteratively weighted least squares iterative method to solve the regression coefficients, and calculates the harmonic impact of each harmonic source in the multi-harmonic source system according to the regression coefficient. In order to verify the effectiveness of the method, the simulation analysis is carried out in the power system analysis software ETAP. The results show that the method can effectively evaluate quantifying the harmonic impact for multi-harmonic sources.